JP7750872B2 - All-solid-state battery binder using conjugated diene polymer, positive electrode layer, negative electrode layer, and electrolyte layer using the binder, and all-solid-state battery including these - Google Patents

Description

The present invention relates to an all-solid-state battery binder using a conjugated diene polymer, a positive electrode layer, a negative electrode layer, an electrolyte layer using the binder, and an all-solid-state battery including these.

Lithium-ion secondary batteries are characterized by their light weight, high energy, and long life, and are widely used as power sources for portable electronic devices such as notebook computers, mobile phones, digital cameras, and video cameras. Furthermore, with the transition to a society with a low environmental impact, lithium-ion secondary batteries are attracting attention as power sources for hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), as well as in the power storage field, such as residential energy storage systems.

However, conventionally, the electrolyte used in lithium-ion secondary batteries has been an organic electrolyte solution in which lithium salt is dissolved in an organic solvent, which has raised safety concerns regarding leakage.

All-solid-state batteries, which use a solid electrolyte instead of a liquid electrolyte and have solid cathode, electrolyte, and anode materials, are proposed as a technology that eliminates the need for flammable electrolyte and dramatically improves safety.

As solid electrolytes for use in all-solid-state batteries, for example, technology has been disclosed that uses sulfide-based materials due to their high lithium ion conductivity.

However, sulfide-based materials have poor chemical stability, and when exposed to air, they react with moisture to generate hydrogen sulfide, impairing electrolyte performance. Therefore, when using such electrolytes, it is desirable to eliminate moisture as much as possible from the battery manufacturing process. Conventional lithium-ion batteries use polyvinylidene fluoride (PVDF) as a binder, which is dissolved in the polar solvent N-methylpyrrolidone (NMP), mixed with electrode constituent materials such as electrode active materials and conductive additives, and then applied to a current collector to produce electrodes. However, due to its hydrophilic nature, NMP is not suitable for use in the manufacture of all-solid-state batteries using sulfide-based solid electrolytes. Therefore, an electrode manufacturing process using a nonpolar solvent with low hydrophilicity is desirable. However, because PVDF does not dissolve in nonpolar solvents, the development of a new binder that dissolves in nonpolar solvents is needed. Patent Document 1 proposes a binder that is soluble in nonpolar solvents.

Since conjugated diene polymers dissolve in non-polar solvents, Patent Document 2 proposes an all-solid-state battery that uses a butadiene-based rubber binder as the all-solid-state battery binder.

JP 2018-125260 A Special table 2019-525427 publication

The conjugated diene polymers described in prior literature are excellent in terms of removing moisture from the manufacturing process because they allow the use of non-polar solvents, but they still lack sufficient binder performance, such as the ability to bind the components of the electrode active material layer together and the solid electrolyte, and the ability to adhere the electrode active material layer to the current collector.

The present invention has been made in consideration of the above problems, and aims to provide an all-solid-state battery binder that has excellent solubility in non-polar solvents and also excellent binder performance, as well as a positive electrode layer, solid electrolyte layer, negative electrode layer, and all-solid-state battery that use the same.

As a result of extensive research into resolving the above-mentioned problems of the prior art, the inventors discovered that the above problems could be solved by using a conjugated diene-based polymer having a modifying group and a specific polymer structure, leading to the completion of the present invention.

That is, the present invention is as follows.
[1]
The polymer contains a conjugated diene polymer having a polymer block mainly composed of vinyl aromatic monomer units and a weight average molecular weight of 40,000 to 2,000,000.
Solid-state battery binder.
[2]
the conjugated diene-based polymer has a modifying group, and the modifying group is at least one selected from the group consisting of an acid anhydride group, a hydroxyl group, a carbonyl group, a carboxyl group, an amino group, an epoxy group, an alkoxysilane group, an amide group, a urethane group, a urea group, an isocyanate group, and an ionic group;
The all-solid-state battery binder according to [1].
[3]
The weight average molecular weight of the conjugated diene polymer is 200,000 to 800,000.
The all-solid-state battery binder according to [1] or [2].
[4]
the content of the polymer block is 40% by weight or less based on the total amount of the conjugated diene-based polymer;
[1] The all-solid-state battery binder according to any one of [1] to [3].
[5]
the amount of vinyl bonds in the conjugated diene monomer units before hydrogenation is 20 mol % to 60 mol % relative to 100 mol % in total of the conjugated diene monomer units;

[1] The all-solid-state battery binder according to any one of [1] to [4].
[6]
the conjugated diene polymer has a toluene-insoluble content of 10 wt % or less;
[1] to [5] The all-solid-state battery binder according to any one of [1] to [5].
[7]
the modifying group is present in an amount of 0.10 mmol or more and 0.50 mmol or less in 100 g of the conjugated diene polymer;
[2] to [6]. The all-solid-state battery binder according to any one of [2] to [6].
[8]
the modifying group is a primary amino group or a secondary amino group;
[2] The all-solid-state battery binder according to any one of [7] to [9].
[9]
an end or a coupling portion of the conjugated diene polymer has the modifying group;
[2] to [8]. The all-solid-state battery binder according to any one of [2] to [8].
[10]
having a polymer block mainly composed of the conjugated diene monomer unit,
[1] The all-solid-state battery binder according to any one of [1] to [9].
[11]
The conjugated diene polymer is hydrogenated.
[1] The all-solid-state battery binder according to any one of [1] to [10].
[12]
the butylene amount and/or propylene amount of the conjugated diene monomer units is 20 mol % to 60 mol % relative to 100 mol % in total of the conjugated diene monomer units;
the conjugated diene polymer has a polymer block mainly composed of a conjugated diene monomer unit;
[12] The all-solid-state battery binder according to any one of [1] to [11].
[13]
The conjugated diene polymer has a loose bulk density of 0.15 g/ ^cm3 or more, a degree of compression of less than 30, and is in the form of powder or crumb.
[1] The all-solid-state battery binder according to any one of [1] to [12].
[14]
the total content of the transition metal element and Al, Li, Fe, Zn, and Mg in the conjugated diene polymer is 200 ppm or less in terms of atoms relative to the conjugated diene polymer;
[14] The all-solid-state battery binder according to any one of [1] to [13].
[15]
The composition contains the conjugated diene polymer and a phosphorus compound, and the phosphorus atom content is 10 ppm or more relative to the conjugated diene polymer.
[14] The all-solid-state battery binder according to any one of [1] to [14].
[16]
The polymer is selected from the group consisting of silica, higher fatty acid metal salts, polyolefins, and fatty acid amides.
[16] The all-solid-state battery binder according to any one of [1] to [15].
[17]
The conjugated diene polymer has isoprene as a conjugated diene polymer unit.
[17] The all-solid-state battery binder according to any one of [1] to [16].
[18]
The moisture content is 200 ppm or less.
[18] The all-solid-state battery binder according to any one of [1] to [17].
[19]
[19] A slurry containing the all-solid-state battery binder according to any one of [1] to [18], wherein the water content is 200 ppm or less.
[20]
[18] The all-solid-state battery binder according to any one of [1] to [18],
a positive electrode active material,
A positive electrode layer having a moisture content of 200 ppm or less.
[21]
[18] The all-solid-state battery binder according to any one of [1] to [18],
an ion-conducting solid electrolyte;
A solid electrolyte layer having a moisture content of 200 ppm or less.
[22]
[18] The all-solid-state battery binder according to any one of [1] to [18],
a negative electrode active material,
A negative electrode layer having a moisture content of 200 ppm or less.
[23]
[20] The cathode layer according to [21], the solid electrolyte layer according to [21], and the anode layer according to [22] are included.
All-solid-state battery.
[24]
The moisture content is 200 ppm or less.
[23] The all-solid-state battery according to [23].
[25]
a step of preparing a slurry containing a conjugated diene polymer having a conjugated diene monomer unit, a polymer block mainly composed of a vinyl aromatic monomer unit, and a modifying group, the conjugated diene polymer having a water content of 1 wt % or less, and a solvent;
and applying the slurry to a substrate and drying the slurry.
A method for manufacturing at least one layer selected from a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, the method comprising the steps of: forming a binder for an all-solid-state battery having a moisture content of 200 ppm or less;

The present invention provides an all-solid-state battery binder that has excellent solubility in non-polar solvents and excellent binder performance, as well as a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and an all-solid-state battery that use the binder.

FIG. 1 is a schematic cross-sectional view showing an example of an all-solid-state battery according to an embodiment of the present invention.

The following provides a detailed description of the form for implementing the present invention (hereinafter referred to as the "present embodiment"). The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be implemented with appropriate modifications within the scope of its essence.

In this specification, the term "polymer" includes both polymers consisting of a single type of monomer unit and copolymers having multiple types of monomer units.

[All-solid-state battery binder]
(Conjugated diene polymer)
The all-solid-state battery binder of this embodiment has a polymer block mainly composed of vinyl aromatic monomer units and contains a conjugated diene polymer having a weight-average molecular weight of 40,000 to 2,000,000.

In this embodiment, the conjugated diene polymer preferably has a modifying group. The term "modifying group" refers to a group capable of binding to the components of the electrode active material layer or the solid electrolyte and/or an adhesive group to the current collector, and refers to a functional group containing an element other than carbon and hydrogen. The structure of the "modifying group" can be confirmed by analyzing the conjugated diene polymer and, if necessary, a potential modifier using various analytical chemistry techniques, such as NMR, spectroscopic analysis, electroanalysis, separation analysis, mass spectrometry, and titration. Methods for identifying the modifying group generally include a combination of NMR, IR, and GC-MS. For example, acid anhydrides such as maleic anhydride and succinic anhydride have an absorption peak near 1750 cm ⁻¹ in IR, and can be identified by analyzing the conjugated diene polymer. Furthermore, analyzing the conjugated diene polymer by chromatography using a column that is adsorbent to the modifying group can identify modifying groups, such as amine-modified groups. For other functional groups, analyzing the conjugated diene polymer by NMR can also identify the chemical shift-specific modifying groups of the functional group. Alternatively, candidates for modifying groups or modifying agents can be selected from various analyses and literature, and the modifying group or modifying agent can be identified based on the agreement between their chemical shifts and the chemical shifts attributable to the modifying group of the conjugated diene polymer.

(Conjugated diene monomer unit)
The conjugated diene monomer constituting the conjugated diene polymer is a diolefin having a pair of conjugated double bonds. Examples of such diolefins include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-cyclopentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-cyclohexadiene, and farnesene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoints of availability and productivity, and 1,3-butadiene is more preferred from the viewpoint of thermal stability. The conjugated diene polymer may be composed of one type of conjugated diene monomer unit, or may be composed of two or more types of conjugated diene monomer units.

The conjugated diene polymer may contain a polymer block primarily composed of conjugated diene monomer units. When the conjugated diene polymer contains a polymer block primarily composed of conjugated diene monomer units, the content of the conjugated diene monomer units contained in this polymer block is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, from the viewpoint of increasing entanglement of polymer chains in the block, thereby improving the binding between components of the all-solid-state battery binder, such as the electrode active material, conductive additive, and solid electrolyte of the electrode active material layer and electrolyte layer, and the adhesion (also known as adhesion) to the current collector. Here, "a polymer block primarily composed of conjugated diene monomer units" refers to a polymer block in which the content of the conjugated diene monomer units exceeds 70% by mass of the entire polymer block.

The upper limit of the content of conjugated diene monomer units contained in the polymer block is not particularly limited, and may be 100% by mass or less, or 99% by mass or less, relative to the total amount of conjugated diene monomer units contained in the conjugated diene-based polymer.

In this embodiment, the binder performance refers to the binding ability of the all-solid-state battery binder to connect the constituent components of the electrode active material layer and electrolyte layer, such as the electrode active material, conductive additive, and solid electrolyte, as well as its adhesion to the current collector.

The conjugated diene polymer may be hydrogenated. In the conjugated diene polymer of this embodiment, from the viewpoints of the solubility of the conjugated diene polymer in solvents with low hydrophilicity, such as non-polar solvents, and the binding and adhesive properties of an all-solid-state battery binder containing the conjugated diene polymer, the vinyl bond content of the conjugated diene monomer units before hydrogenation is preferably 20 mol% or more, more preferably 25 mol% or more, even more preferably 30 mol% or more, and even more preferably 35 mol% or more, relative to 100 mol% of the total conjugated diene monomer units. In particular, when hydrogenated, if the vinyl bond content is too low, the conjugated diene polymer may crystallize, resulting in a significant decrease in solubility in non-polar solvents.

The upper limit of the vinyl bond content of the conjugated diene monomer units before hydrogenation may be 100 mol% or less, or 99 mol% or less, preferably 80 mol% or less, and more preferably 70 mol% or less, relative to a total of 100 mol% of the conjugated diene monomer units. From the viewpoint of rubber elasticity, 60 mol% or less, 50 mol% or less, or 40 mol% or less are preferred.

Furthermore, even when the conjugated diene polymer contains a polymer block mainly composed of conjugated diene monomer units, the preferred range of the vinyl bond content before hydrogenation is the same as above.

The term "vinyl bond content before hydrogenation" refers to the amount (molar ratio) of 1,2-bonds relative to the total amount of 1,4-bonds (cis and trans) and 1,2-bonds resulting from conjugated diene monomer units in a conjugated diene polymer before hydrogenation. However, if the conjugated diene monomer units are incorporated into the polymer via 3,4-bonds, the term refers to the total amount (molar ratio) of 1,2-bonds and 3,4-bonds relative to the total amount of 1,4-bonds, 1,2-bonds, and 3,4-bonds. In other words, although the term "before hydrogenation" is used for this definition, this is because hydrogenation results in a state that can no longer be called a "vinyl bond." Even after hydrogenation, it is possible to distinguish between 1,4-bonds, 1,2-bonds, and 3,4-bonds, so this is an indicator that can be similarly quantified for polymers after hydrogenation.

The butylene and/or propylene content of the conjugated diene polymer is preferably 20 mol% or more, more preferably 25 mol% or more, even more preferably 30 mol% or more, and even more preferably 35 mol% or more. The upper limit of the butylene and/or propylene content of the conjugated diene polymer may be 100 mol% or less, or may be 99 mol% or less, preferably 80 mol% or less, and even more preferably 70 mol% or less. From the viewpoint of rubber elasticity, it is preferably 60 mol% or less, 50 mol% or less, or 40 mol% or less. Having the butylene and/or propylene content within the above ranges tends to further improve solubility in nonpolar solvents and binder performance.

Here, "amount of butylene and/or propylene" refers to the amount (molar ratio) of 1,2-bonds relative to the total amount of 1,4-bonds (cis and trans) and 1,2-bonds resulting from conjugated diene monomer units in the conjugated diene polymer after hydrogenation. However, when the conjugated diene monomer units are incorporated into the polymer via 3,4-bonds, the term refers to the total amount (molar ratio) of 1,2-bonds and 3,4-bonds relative to the total amount of 1,4-bonds, 1,2-bonds, and 3,4-bonds. The amount of butylene and/or propylene can be controlled by the amount of vinyl bonds before hydrogenation and the hydrogenation rate.

The vinyl bond content and butylene and/or propylene content of a conjugated diene polymer before hydrogenation can be measured using a nuclear magnetic resonance (NMR) spectrometer or the like, specifically by the method described in the examples below.

The vinyl bond amount before hydrogenation can also be measured by proton nuclear magnetic resonance ( ¹ H-NMR) using a hydrogenated conjugated diene polymer as a sample. This method will be specifically described using as an example a conjugated diene polymer in which the vinyl aromatic monomer unit is styrene and the conjugated diene monomer unit is 1,3-butadiene.

Measurement is performed under the following conditions using ECS400 (product name manufactured by JEOL) as the measuring instrument, deuterated chloroform as the solvent, and a sample concentration of 50 mg/mL.
(Measurement conditions)
Observation frequency: 400MHz
Chemical shift reference: chloroform (7.26 ppm)
Pulse delay: 3 seconds Number of scans: 256 times Pulse width: 45°
Measurement temperature: 26℃

The amount of vinyl bonds before hydrogenation can be determined using the area value of signals in the chemical shift range of 10.0 ppm to 0.0 ppm in the obtained NMR spectrum. More specifically, it can be determined by the following formulas (1) to (6).
(area value per proton of styrene monomer unit)
=(X ₂ -X ₁ )/5 (1)
(Area value per proton of unhydrogenated 1,2-bond butadiene monomer unit)
= X ₃ / 2 (2)
(Area value per proton of unhydrogenated 1,4-bonded butadiene monomer unit)
=(X ₄ -(X ₃ /2))/2 (3)
(Area value per proton of hydrogenated 1,2-bond butadiene monomer unit)
= X ₅ / 3 (4)
(Area value per proton of hydrogenated 1,4-bonded butadiene monomer unit)
= (X ₆ - (1) x 3 - (2) x 3 - (3) x 4 - (4) x 8 - X ₇ )/8 (5)
(Amount of vinyl bond (mol %) before hydrogenation)
= ((2) + (4)) / ((2) + (3) + (4) + (5)) × 100 (6)

In the above formulas (1) to (5), the symbols X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are defined as follows:
X ₁ : Area value of the range surrounded by the NMR spectrum and a line connecting the positions of the smallest signal intensity in each of the sections of 7.26 ppm to 7.25 ppm and 7.27 ppm to 7.26 ppm, with 7.26 ppm as the center. X ₂ : Area value of the range surrounded by the NMR spectrum and a line connecting the signal positions of 8.0 ppm and 6.0 ppm. X ₃ : Area value of the range from the chemical shift of the position of the smallest signal intensity between 5.2 ppm and 4.9 ppm to 4.0 ppm, among the area values surrounded by the NMR spectrum and a line connecting the signal positions of 6.0 ppm and 4.0 ppm. X ₄ : Area value _X5 in the range from the chemical shift at the position with the smallest signal intensity between 5.2 ppm and 4.9 ppm to 6.0 ppm among the area values surrounded by the line connecting the signal positions at 6.0 ppm and 4.0 ppm and the NMR spectrum : The area enclosed by the NMR spectrum and a line connecting the signal positions at 4.0 ppm and 0.3 ppm, the area ranging from the chemical shift at the position with the smallest signal intensity among the valleys in the NMR spectrum between 1.05 ppm and 0.85 ppm to 0.3 ppm (however, if no valley exists between 1.05 ppm and 0.85 ppm, the area is the area ranging from the chemical shift at the position with the smallest signal intensity between 1.05 ppm and 0.85 ppm to 0.3 ppm among the area enclosed by the NMR spectrum and a line connecting the signal positions at 4.0 ppm and 0.3 ppm).
_X6 : Area value of the range surrounded by the NMR spectrum and a line connecting the signal positions at 4.0 ppm and 0.3 ppm. _X7 : Area value of the range surrounded by the NMR spectrum and a line connecting the positions of the smallest signal intensity in each of the 1.49 ppm to 1.50 ppm section and the 1.50 ppm to 1.51 ppm section, with 1.50 ppm as the center (however, if the line connecting the positions of the smallest signal intensity is above the NMR spectrum, it is set to 0).

Furthermore, (1) to (5) in equations (5) and (6) are values obtained from the above equations (1) to (5), respectively.

The vinyl bond amount, butylene amount, and/or propylene amount can be controlled within the above numerical ranges during the production of the conjugated diene polymer by adding a Lewis base, such as an ether or an amine compound, as a vinyl bond amount adjuster (hereinafter referred to as a vinylating agent) or by controlling the temperature during production. Generally, the vinyl bond amount tends to increase by increasing the amount of vinyl bond amount adjuster or lowering the temperature during production.

(vinyl aromatic monomer unit)
In the conjugated diene polymer of this embodiment, from the viewpoints of the solubility of the conjugated diene polymer in hydrocarbon solvents and the binding and adhesive properties of an all-solid-state battery binder containing the conjugated diene polymer, the content of the vinyl aromatic monomer unit is preferably 80% by mass or less, relative to the total amount of the conjugated diene polymer. From the same viewpoint, and from the viewpoint of further improving flexibility, the content is more preferably 5% by mass or more and 60% by mass or less. From the viewpoint of further improving the low-temperature cracking resistance of each binder-containing layer, the content is even more preferably 10% by mass or more, more preferably 12% by mass or more. From the viewpoint of suppressing deterioration of battery performance due to gaps caused by shrinkage of the solid electrolyte or electrode active material caused by repeated charge and discharge, the content is preferably 15% by mass or more, and more preferably 20% by mass or more. The upper limit is more preferably 40% by mass or less, even more preferably 35% by mass or less, and particularly preferably 30% by mass or less.

The content of vinyl aromatic monomer units in the conjugated diene polymer can be measured by ultraviolet spectrophotometry or proton nuclear magnetic resonance ( ¹ H-NMR) spectroscopy. Specifically, it can be measured by the method described in the examples.

In the conjugated diene polymer of this embodiment, from the viewpoints of the solubility of the conjugated diene polymer in nonpolar solvents and the binding properties, adhesiveness, and heat resistance of the all-solid-state battery binder containing the conjugated diene polymer, the content of the polymer block primarily composed of vinyl aromatic monomer units is preferably 40% by mass or less, relative to the total amount of the conjugated diene polymer. From the same viewpoint, and from the viewpoint of further improving flexibility, the content is more preferably 5% by mass or more and 35% by mass or less. From the viewpoint of further improving the low-temperature cracking resistance of each layer containing the binder, the content is even more preferably 10% by mass or more and 33% by mass or less. From the viewpoint of preventing deterioration of battery performance due to the shrinkage of the solid electrolyte or electrode active material caused by repeated charge and discharge, the content is preferably 15% by mass or more, and more preferably 20% by mass or more.

In addition, from the standpoint of heat resistance and strength, it is preferable that the polymer block mainly composed of vinyl aromatic monomer units be present in the main chain of the conjugated diene polymer, and it is preferable that it be present in the first or second block counting from the end of the polymer chain.

The content of polymer blocks primarily composed of vinyl aromatic monomer units in a conjugated diene polymer can be calculated using the mass of the polymer blocks primarily composed of vinyl aromatic monomer units (excluding vinyl aromatic monomer units with an average degree of polymerization of approximately 30 or less) determined by a method in which a copolymer before hydrogenation is oxidatively decomposed with t-butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in I.M. KOLTHOFF, et al., Polym. Sci. 1, 429 (1946)) (hereinafter also referred to as the "osmium tetroxide decomposition method").

Furthermore, the content of polymer blocks mainly composed of vinyl aromatic monomer units in the hydrogenated conjugated diene polymer can be measured by nuclear magnetic resonance (NMR) using the hydrogenated conjugated diene polymer (hydrogenated copolymer (b)) according to the method described in Y. Tanaka, et al., RUBBER CHEMISTRY and TECHNOLOGY 54, 685 (1981) (hereinafter also referred to as the "NMR method").

The NMR method will be specifically explained by taking as an example the case where the vinyl aromatic monomer unit is styrene and the conjugated diene monomer unit is 1,3-butadiene.
30 mg of the hydrogenated conjugated diene polymer is dissolved in 1 g of deuterated chloroform, and the content (Ns value) of a polymer block (in this case, a polystyrene block) mainly composed of a vinyl aromatic monomer unit is measured by H-NMR using the sample. The Ns value is determined from the ratio of the integrated value of the chemical shift from 6.9 ppm to 6.3 ppm to the total integrated value.
Block styrene strength (b-St strength)
= (integrated value from 6.9 ppm to 6.3 ppm)/2
Random styrene strength (r-St strength)
= (integrated value from 7.5 ppm to 6.9 ppm) - 3 × (b - St)
Ethylene-butylene strength (EB strength)
= total integrated value - 3 x {(b - St intensity) + (r - St intensity)} / 8
Polystyrene block content (Ns value) obtained by NMR method
=104×(b-St intensity)
/[104×{(b-St intensity)+(r-St intensity)}+56×(EB intensity)]

Here, there is a correlation represented by the following formula between the content of polymer blocks mainly composed of vinyl aromatic monomer units in a conjugated diene polymer before hydrogenation, measured by the osmium tetroxide decomposition method (referred to as the "Os value"), and the content of polymer blocks mainly composed of vinyl aromatic monomer units in a conjugated diene polymer after hydrogenation, measured by the NMR method (referred to as the "Ns value"). Specifically, it can be measured by the method described in the examples.
Os value = -0.012 (Ns value)² + 1.8 (Ns value) - 13.0

A "polymer block primarily composed of vinyl aromatic monomer units" refers to a polymer block in which the content of the vinyl aromatic monomer units exceeds 70% by mass relative to the entire polymer block. From the viewpoint of the binding and adhesive properties of an all-solid-state battery binder containing a conjugated diene polymer, the content of vinyl aromatic monomer units in the polymer block primarily composed of vinyl aromatic monomer units is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. Within the above range, the polymer block primarily composed of vinyl aromatic monomer units has high cohesive strength and serves as a physical crosslinking point. The upper limit of the content of vinyl aromatic monomer units in the polymer block primarily composed of vinyl aromatic monomer units is not particularly limited, but may be 100% by mass or less, or 99% by mass or less.

The vinyl aromatic monomer is not particularly limited, but examples include vinyl aromatic compounds such as styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. Of these, from the standpoints of availability and productivity, styrene, α-methylstyrene, and p-methylstyrene are preferred, and styrene is more preferred. The polymer block primarily composed of a vinyl aromatic compound may be composed of one type of vinyl aromatic monomer, or two or more types.

(Modifying group)
When the conjugated diene polymer has a modifying group, it is preferably a group capable of binding to the components of the electrode active material layer or the solid electrolyte and/or a group capable of adhering to the current collector. Examples of such modifying groups include, but are not limited to, acid anhydride groups, hydroxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, carboxyl groups, thiocarboxylic acid groups, aldehyde groups, thioaldehyde groups, carboxylic acid ester groups, amide groups, imide groups, sulfonic acid ester groups, phosphate ester groups, amino groups, imino groups, cyano groups, urethane groups, urea groups, pyridyl groups, quinoline groups, epoxy groups, thioepoxy groups, sulfide groups, isocyanate groups, isothiocyanate groups, silicon halide groups, silanol groups, alkoxysilane groups, tin halide groups, alkoxytin groups, phenyltin groups, and ionic groups. The conjugated diene polymer may have one of the above modifying groups alone or in combination of two or more. Examples of the ionic group include a sulfonic acid group, a sulfonimide group, a sulfate group, a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, and an ammonium group or a salt thereof.

In particular, in the case of batteries using a sulfide-based solid electrolyte or an oxide-based solid electrolyte, from the viewpoint of further improving the binding strength between the components of the electrode active material layer or the solid electrolyte, or the adhesion to the current collector, it is preferable that the modifying group possessed by the conjugated diene polymer be one or more selected from the group consisting of an acid anhydride group, a hydroxyl group, a carbonyl group, a carboxyl group, an amino group, an epoxy group, an alkoxysilane group, an amide group, a urethane group, a urea group, an isocyanate group, and an ionic group.

Among these, from the viewpoints of availability and suppression of hydrogen sulfide generation due to reaction with sulfide-based solid electrolytes, acid anhydride groups, carboxyl groups, amino groups, epoxy groups, alkoxysilane groups, and hydroxyl groups are more preferred as modifying groups. Furthermore, from the viewpoint of suppressing alcohol generation, acid anhydride groups, carboxyl groups, amino groups, epoxy groups, and hydroxyl groups are even more preferred as modifying groups. Furthermore, from the viewpoints of productivity (ease of adjusting the modification rate and safety), amino groups, hydroxyl groups, carboxyl groups, and acid anhydride groups are more preferred as modifying groups. Furthermore, from the viewpoints of bond formation through chemical reactions with functional groups on the surface of current collectors and battery components, and hydrogen bonding properties that act as donors and acceptors, amino groups, hydroxyl groups, and carboxyl groups are preferred as modifying groups. In particular, from the viewpoints of hydrogen bonding and bond formation with materials that have carboxyl groups as surface functional groups, such as conductive additives, amino groups are preferred as modifying groups. Among amino groups, primary amino groups and secondary amino groups are preferred from the viewpoint of bond formation by chemical reaction and hydrogen bonding properties acting as donors and acceptors with respect to functional groups on the surface of the current collector or the surface of the battery components.

When a conjugated diene polymer has a functional group that does not correspond to a binding group for the constituent components of the electrode active material layer or the solid electrolyte or an adhesive group for the current collector, the adhesion of the conjugated diene polymer to the constituent components of the electrode active material layer, the solid electrolyte, or the current collector can be further improved by reacting the functional group of the conjugated diene polymer with another compound that can interact with the functional group, the constituent components of the electrode active material layer, the solid electrolyte, or the current collector. In other words, the functional group of the conjugated diene polymer interacts with the other compound through intermolecular forces or chemical bonds, and the other compound interacting with the functional group interacts with the constituent components of the electrode active material layer, the solid electrolyte, or the current collector through intermolecular forces or chemical bonds, thereby further improving the binding and adhesive properties of the conjugated diene polymer.

Such other compounds are not particularly limited, but include, for example, carbodiimide compounds, amide condensation agents such as diphenylphosphoric acid azide, alkoxysilane compounds, amino compounds, hydroxy compounds, isocyanate compounds, and epoxy compounds. These other compounds may be used alone or in combination of two or more.

Carbodiimide compounds are not particularly limited, but examples include N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

Alkoxysilane compounds are not particularly limited, but examples include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

Amine compounds are not particularly limited, but examples include diaminobutane, diaminopentane, diaminohexane, diaminoheptane, and diaminooctane.

Hydroxy compounds are not particularly limited, but examples include dihydroxybutane, dihydroxypentane, dihydroxyhexane, dihydroxyheptane, and dihydroxyoctane.

Isocyanate compounds are not particularly limited, but examples include hexanemethylene diisocyanate, 1,4-phenylene diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate.

Epoxy compounds are not particularly limited, but examples include ethylene glycol diglycidyl ether and 1,4-butanediol diglycidyl ether.

These compounds can also be used as components of the electrode active material layer or as conjugated diene-based polymers having binding groups for the solid electrolyte or adhesive groups for the current collector.

The content of the modifying groups in the conjugated diene polymer described above is not particularly limited, but from the viewpoint of further improving binding strength and adhesiveness, it is preferably 0.5 groups/chain or more. From the same viewpoint, it is more preferably 0.7 groups/chain or more, even more preferably 1.0 groups/chain or more, and even more preferably 2.0 groups/chain or more. By having a content of 0.5 groups/chain or more, the modifying groups can more fully interact with the components of the electrode active material layer, the solid electrolyte, or the current collector, further improving adhesiveness. On the other hand, from the viewpoint of dispersibility of the conductive additive when formed into a slurry, it is 50 groups/chain or less, more preferably 20 groups/chain or less, even more preferably 10 groups or less, more preferably 2.0 groups/chain or less, and even more preferably 1.0 groups or less.

The content of modifying groups is preferably 300 or less per chain, from the viewpoint of further preventing problems such as gelation of all-solid-state battery binders containing conjugated diene polymers. Here, "chain" refers to a single polymer molecule, such as a conjugated diene polymer, and in polymer structures where the polymer structure is branched by chemical bonds, each branched chain is counted as one molecular chain.

In addition to the modifying groups described above, the conjugated diene polymer may also have functional groups or polymer chains that improve ionic conductivity. Examples of such functional groups and polymer chains include, but are not limited to, ether groups, crown ethers, polyethylene glycols, boronic acid groups, boronic acid ester groups, ionic groups containing lithium ion electrolytes used in lithium ion batteries, and ionic groups containing ionic liquids.

(Hydrogenation)
The conjugated diene polymer is preferably hydrogenated. The hydrogenation rate relative to 100 mol% of the total of conjugated diene monomer units is preferably 30 mol% or more from the viewpoint of electrochemical stability of the conjugated diene polymer, more preferably 50 mol% or more from the viewpoint of thermal stability, even more preferably 70 mol% or more from the viewpoint of further improving adhesiveness, and particularly preferably 90 mol% or more from the viewpoint of improving the strength of the electrode film by entanglement of polymer chains.

The hydrogenation rate of conjugated diene polymers can be measured using a nuclear magnetic resonance (NMR) spectrometer, etc., and specifically, can be measured by the method described in the examples.

In addition, the hydrogenation rate can be controlled within the above numerical range, for example, by adjusting the amount of hydrogen or catalyst during hydrogenation.

(Toluene insolubles)
The toluene insoluble content of the conjugated diene polymer is preferably 10 wt % or less, more preferably 5 wt % or less, even more preferably 3 wt % or less, and particularly preferably 1 wt % or less. The lower limit of the toluene insoluble content is not particularly limited, but is 0 wt %. By keeping the toluene insoluble content at 10 wt % or less, the smoothness of the coating film tends to be further improved. The toluene insoluble content can be measured by the method described in the examples.

(Random copolymer block)
The conjugated diene polymer used in the all-solid-state battery binder of this embodiment may further have a random copolymer block of conjugated diene monomer units and vinyl aromatic monomer units. By forming the random structure, the affinity between the conjugated diene polymer and the components of the electrode active material layer or the solid electrolyte can be improved, thereby improving the binding property, and the viscoelasticity can be controlled to impart vibration damping properties in the operating temperature range of the battery, thereby improving the durability of the battery.

Examples of vinyl aromatic monomers and conjugated diene monomers that may be contained in the random copolymer block of a conjugated diene compound and a vinyl aromatic compound include those exemplified above as those that may be contained in the block primarily composed of a vinyl aromatic polymer and the block primarily composed of a conjugated diene polymer.

There are no particular limitations on the distribution of vinyl aromatic monomer units in the random copolymer block, and the vinyl aromatic monomer units may be distributed uniformly or in a tapered pattern. Furthermore, there may be multiple regions where the vinyl aromatic monomer units are distributed uniformly and/or multiple regions where the vinyl aromatic monomer units are distributed in a tapered pattern, and there may be multiple segments with different vinyl aromatic monomer unit contents.

In the conjugated diene polymer of this embodiment, in addition to the conjugated diene monomer and vinyl aromatic monomer, other monomers copolymerizable with the conjugated diene monomer and vinyl aromatic monomer can also be used.

(Structure of conjugated diene polymer)
The structure of the conjugated diene polymer of the present embodiment is not particularly limited, but examples thereof include those having a structure represented by the following formula in part or those having a structure represented by the following formula: In the following formula, the description of the modifying group may be omitted in some cases.

(a-b) _n , b-(a-b) _n , a-(ba) _n , (a-b) _m -X, (ba-a) _m -X, [(a-b) _n ] _m -X, [(ba-a) _n ] _m -X, [b-(a-b) _n ] _m -X, [a-(ba) _n ] _m -X, [(a-b) _n -a] _m -X, [(b-a) _n -b] _m -X, (ac) _n , c-(ac) _n , a-(ca) _n , (ac) _m -X, (ca) _m -X, [(ac) _n ] _m -X, [(c-a) _n ] _m -X, [c-(a-c) _n ] _m -X, [a-(ca) _n ] _m -X, [(ac) _n -a] _m -X, [(ca) _n -c] _m -X, c-(ba) _n , c-(ab) _n , c-(a-ba) _n , c-(ba-b) _n , a-c-(ba) _n , a-c-(ab) _n , a-c-(ba) _n -b, [(a-b-c) _n ] _m -X, [a-(b-c) _n ] _m -X, [(a-b) _n -c] _m -X, [(a-b-a) _n -c] _m -X, [(b-a-b) _n -c] _m -X, [(c-ba) _n ] _m -X, [c-(b-a)n] _m -X, [c-(ab-a) _n ] _m -X, [c-(b-a-b) _n ] _m -X, a-(b-c) _n , a-(c-b) _n , a-(c-b-c) _n , a-(b-c-b) _n , c-a-(b-c) _n , c-a-(c-b) _n , c-a-(b-c) _n -b, [(c-b-a) _n ] _m -X, [c-(b-a) _n ] _m -X, [(c-b) _n -a] _m -X, [(c-b-c) _n -a] _m -X, [(b-c-b) _n -a] _m -X, [(a-b-c) _n ] _m -X, [a-(b-c) _n ] _m -X, [a-(c-b-c) _n ] _m -X, [a-(b-c-b) _n ] _m -X, b-(ac) _n , b-(ca) _n , b-(c-ac) _n , b-(a-c-a) _n , c-b-(ac) _n , c-b-(ca) _n , c-b-(ac) _n -a, [(c-a-b) _n ] _m -X, [c-(ab) _n ] _m -X, [(c-a) _n -b] _m -X, [(c-a-c) _n -b] _m -X, [(b-a-c) _n ] _m -X, [b-(a-c) _n ] _m -X, [b-(c-ac) _n ] _m -X, [b-(ac-a) _n ] _m -X, (b ₁ -b ₂ ) _n -a, (b ₁ -b ₂ -b) _n -a, (b ₁ -b ₂ -a) _n , (b ₁ -b ₂ -a) _n -b, (b ₁ -b ₂ -ab) _n , (b ₁ -b ₂ -a) _m -X, (b ₁ -b ₂ -ab) _m -X.

In the above formulas, a represents a vinyl aromatic polymer block mainly composed of vinyl aromatic monomer units, b represents a conjugated diene polymer block mainly composed of conjugated diene monomer units, _b1 and _b2 represent conjugated diene polymer blocks mainly composed of conjugated diene monomer units (provided that the vinyl bond amount in _b1 is smaller than the vinyl bond amount in _b2 ), and c represents a random copolymer block of a conjugated diene monomer and a vinyl aromatic monomer. When all of _b1 , _b2 , and b are present, the vinyl bond amount of b is not particularly limited. n represents an integer of 1 or more, preferably an integer of 1 to 5. m represents an integer of 2 or more, preferably an integer of 2 to 11. X represents a residue of a coupling agent or a residue of a polyfunctional initiator.

From the viewpoint of the binding and adhesive properties of an all-solid-state battery binder containing the conjugated diene polymer, the conjugated diene polymer of this embodiment preferably mainly contains a structure having a b, _b1 , or _b2 block. Furthermore, from the viewpoint of improving mechanical strength, it is more preferable that the polymer be a polymer represented by at least one structural formula selected from a-b, a-ba, _a - _ba -b, _b1 - _b2 -a, b1-b2-a-b, and _b1 - _b2 -ba, and coupling products thereof. From the viewpoint of the solubility of the conjugated diene polymer in nonpolar solvents and the binding and adhesive properties of an all-solid-state battery binder containing the conjugated diene polymer, a structure having two or more a blocks in the molecular chain is preferred.

It is also preferable that the terminal or coupling portion of the conjugated diene polymer has a modifying group. This tends to further improve the balance of adhesiveness, binding properties, and dispersibility of the conductive additive.

(Weight average molecular weight and molecular weight distribution)
From the viewpoints of the binding property and adhesiveness of the all-solid-state battery binder containing a conjugated diene polymer, and its solubility in nonpolar solvents, the weight-average molecular weight (Mw) (hereinafter also referred to as "Mw") of the conjugated diene polymer is preferably 40,000 to 2,000,000, more preferably 60,000 to 1,500,000, even more preferably 100,000 to 1,000,000, and even more preferably 200,000 to 800,000. The lower limit of Mw is more preferably 200,000 or more, more preferably 250,000 or more. The upper limit is more preferably 500,000 or less, even more preferably 450,000 or less. Adjusting the Mw within a preferred range is important from the viewpoints of storage stability and coatability, since the solvent used in preparing the slurry does not volatilize immediately during storage of the solution containing the conjugated diene polymer and the solvent used in preparing the slurry, or when applied to a current collector. From the viewpoint of vapor pressure reduction by the polymer solution, a higher molecular weight of the conjugated diene polymer increases the degree of vapor pressure reduction, making it possible to suppress solvent volatilization. Although increasing the molecular weight of the binder offers these benefits, conventional lithium-ion batteries use N-methyl-2-pyrrolidone (NMP) as the solvent, making it difficult to use high-molecular-weight polymers due to the low solubility of conjugated diene-based polymers. In all-solid-state batteries, non-polar solvents, such as hydrocarbon solvents, are preferred, and the excellent solubility of conjugated diene-based polymers in hydrocarbon solvents makes the use of high-molecular-weight polymers possible. Furthermore, when comparing NMP with non-polar solvents, such as hydrocarbon solvents, NMP has a lower vapor pressure, and the need for high-molecular-weight polymers has not been emphasized in terms of volatility. However, non-polar solvents have a higher vapor pressure than NMP, making the volatility issue more pronounced, and creating a need for higher molecular weight polymers. On the other hand, when using a battery manufacturing method that minimizes the use of solvents, conjugated diene-based polymers without modifying groups are preferred due to their excellent solubility in non-polar solvents.

A weight-average molecular weight (Mw) of 30,000 or more tends to improve the entanglement of polymer chains and the cohesive strength of vinyl aromatic polymer blocks, resulting in improved binding and adhesive strength. In particular, a weight-average molecular weight (Mw) of 2,000,000 or less tends to lower the viscosity when dissolved in a non-polar solvent, improving the film-forming properties of each layer during electrode production.

In addition, heat resistance is required for some applications of all-solid-state batteries, and there is a concern that binder flow at high temperatures could reduce battery performance. In such cases, a high weight-average molecular weight (Mw) of the conjugated diene polymer is preferable to suppress flow. The required heat resistance depends on the specifications of the device, so there are no particular restrictions on the applications requiring heat resistance. However, examples of applications requiring heat resistance include power supplies for automobiles and automobile motors installed in the engine compartment, power supplies for motors installed in large industrial machinery, power supplies for medical equipment that require sterilization heating, and small power supplies mounted directly on home appliances and automotive printed wiring boards. Heat resistance may also be required when undergoing a solder reflow process, such as when directly mounting on a printed wiring board.

The weight-average molecular weight (Mw) of a conjugated diene polymer is the weight-average molecular weight (Mw) determined by measuring the peak molecular weight of a chromatogram obtained by gel permeation chromatography (GPC) based on a calibration curve obtained by measuring commercially available standard polystyrene. The calibration curve can be prepared using the peak molecular weight of the standard polystyrene.

The molecular weight distribution of the conjugated diene polymer before modification can also be determined by GPC measurement, and the molecular weight distribution can be determined from the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn).

The single-peak molecular weight distribution of the conjugated diene polymer measured by GPC is preferably 5.0 or less, more preferably 4.0 or less, even more preferably 3.0 or less, and even more preferably 2.5 or less. The lower limit of the molecular weight distribution is not particularly limited, but may be 1.0 or more, or 1.1 or more.

(moisture content)
The all-solid-state battery binder preferably does not contain moisture, and the moisture content of the all-solid-state battery binder is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. The moisture contained in the all-solid-state battery binder may be removed by drying in a dryer at normal pressure or reduced pressure, or by storing in a dehumidified environment. In this case, the binder may be stored under heating, or under heating and pressure using a press or roll, etc.

In this case, the moisture content of the all-solid-state battery binder before drying or dehumidification may be 200 ppm or more. Furthermore, from the viewpoint of moisture removal efficiency, the moisture content of the conjugated diene polymer used in the all-solid-state battery binder is preferably 1 wt% or less, more preferably 0.5 wt% or less, even more preferably 0.1 wt% or less, even more preferably 0.05 wt% or less, and particularly preferably 0.02 wt% or less. The moisture contained in the conjugated diene polymer may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment. This may be done under heating, or under both heating and pressure using a press or roll, etc.

The conjugated diene polymer may be in the form of pellets. However, if the moisture content of the polymer is reduced before preparing the slurry, a form with a large specific surface area is preferred, preferably in the form of crumbs or powder, from the perspective of moisture removal efficiency. The conjugated diene polymer-containing slurry preferably has a water content of 1 wt% or less. However, since the slurry is diluted with solvents and other components in addition to the polymer, it is possible to prepare a slurry with a water content of 1 wt% or less even if the polymer's moisture content exceeds 1 wt%. In other words, since the moisture derived from the conjugated diene polymer is also diluted, the moisture content of the conjugated diene polymer may be 1 wt% or more. It is desirable to keep the moisture content of the binder at 200 ppm or less. Therefore, if the moisture content of the slurry is high, it is preferable to use a solvent that forms an azeotrope with water in the slurry to increase the efficiency of moisture removal by solvent removal.

When a conjugated diene polymer is fed through a feeder, if the polymer is compressed in the feeder and fed as a partial mass, the feed becomes unstable, resulting in variations in the blending amount and affecting battery performance. From the perspective of stable feeding, the degree of compression, measured using the method described in the examples, is preferably less than 30, more preferably 20 or less, even more preferably 15 or less, and even more preferably 10 or less.

From the viewpoint of filling a large amount of conjugated diene polymer into a feeder of a given volume, the loose bulk density is preferably 0.15 g/cm or ^more , more preferably 0.20 g/cm or ^more , and even more preferably 0.22 g/cm or ^more . The upper limit is preferably 0.30 g/cm or ^less , more preferably 0.25 g/cm or ^less .

The total content of transition metal elements and Al, Li, Zn, and Mg in the conjugated diene polymer is preferably 200 ppm or less in atomic terms relative to the conjugated diene polymer. Transition metals include V, Ti, Mn, Fe, Co, and Ni.

Generally, compounds containing such metal atoms contained in polymerization initiators used in the production of block copolymers by anionic living polymerization, in hydrogenation catalysts used in hydrogenation reactions, and/or in the desolvation process of polymerization react with moisture in the air to produce compounds containing such metals, as described below, which may remain in the conjugated diene polymer.

The compounds containing transition metal elements (e.g., Ti, Ni, Co) and/or Li in the conjugated diene polymer are not particularly limited, but examples include oxides of each atom such as titanium oxide, amorphous titanium oxide, orthotitanic acid, metatitanic acid, titanium hydroxide, nickel hydroxide, nickel monoxide, lithium oxide, lithium hydroxide, cobalt oxide, and cobalt hydroxide, as well as composite oxides of each atom with different metals such as lithium titanate, barium titanate, strontium titanate, nickel titanate, and nickel-iron oxide. In addition, metals such as Al, Li, Zn, Fe, and Mg remain in the conjugated diene polymer as metal residues.

Here, "atomic equivalent" generally refers to the mass per metal atom calculated from the residual weight and molecular weight of the compound containing the metal atom. However, if the compound containing the metal atom can be identified, the calculation may be performed using the above method. However, since such identification is often difficult, the total metal content relative to the total amount in the conjugated diene polymer is determined in atomic equivalent mass by measuring the total content of the metal atoms using the method described in the Examples.

By keeping the total content of transition metal elements and Al, Li, Zn, Fe, and Mg in the conjugated diene polymer to 200 ppm or less, calculated on an atomic basis, the thermal stability of the conjugated diene polymer is maintained and the deterioration of heat aging resistance of all-solid-state batteries using the conjugated diene polymer as a binder is suppressed. The detailed mechanism of this phenomenon is unknown and is not limited to the following. However, it is generally known that when a polymer is exposed to high temperatures, carbon radicals are generated, which react with oxygen in the air to generate hydroperoxides. In the presence of the metal compounds described above, decomposition into free radicals via a redox reaction is promoted. Furthermore, the hydrogenated block copolymer itself reacts with the metal compounds described above to generate free radicals. Alternatively, a charge transfer complex and/or active oxygen are generated between metal ions derived from the metal compounds and oxygen in the air, and these active species react with the hydrogenated block copolymer to generate carbon radicals. Although the reaction mechanism is not limited to these, according to the above-mentioned reaction mechanism, when the amount of the above-mentioned metal is large, there tends to be a large amount of free radicals derived from the metal compound, and as a result, active species such as carbon radicals and hydroperoxides are generated in the hydrogenated block copolymer. These active species cause bonding between radicals and the generation of further radicals, which leads to deterioration of the polymer and causes bonding between hydrogenated block copolymers, which raises concerns about cracking of the layer using the binder, reduced adhesion and binding properties, and reduced impact resistance due to hardening.

The total content is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 70 ppm or less, and particularly preferably 50 ppm or less. There is no particular lower limit for the total content, but it is 0 ppm.

Known methods can be used to reduce the total content to 200 ppm or less. For the sole purpose of deactivating and neutralizing the hydrogenation catalyst, methods such as adding water and carbon dioxide gas after the hydrogenation reaction of the block copolymer to neutralize the hydrogenation catalyst residue, and adding water, carbon dioxide gas, and an acid to neutralize the hydrogenation catalyst residue are commonly used. However, to reduce the total metal content, neutralization alone is insufficient, and therefore, it is preferable to further remove the metals using decantation or a centrifuge. More specifically, the method described in Patent Application No. 2014-557427 can be cited. When removing metal residues by contacting the post-hydrogenation polymer solution with water, adding acids such as sulfuric acid, hydrochloric acid, and nitric acid to the conjugated diene polymer solution makes it easier for the metal residues to be extracted into the aqueous phase when mixed with water. To further remove the metal residues, increasing the stirring intensity (P/V value) when contacting the polymer solution with water disrupts the interaction between the polymer and the metal residues, thereby further extracting the metal residues into the aqueous phase. Furthermore, by separating the decantation and centrifugation steps, more metal residues can be removed.

[Method for producing conjugated diene polymer]
The method for producing the conjugated diene polymer of the present embodiment is not particularly limited, and may include, for example, a polymerization step, a modification step, and a hydrogenation step as described below.

The polymerization process is not particularly limited, but for example, is a process in which a conjugated diene compound and a vinyl aromatic compound are polymerized in an organic solvent using an organic alkali metal compound as a polymerization initiator to obtain a random copolymer and/or a block copolymer as represented by the above structure.

The hydrogenation process is not particularly limited, but is, for example, a process in which the conjugated diene polymer obtained in the polymerization process is hydrogenated.

The modification process is not particularly limited, but is, for example, a process in which a conjugated diene polymer is reacted with a modifier to carry out a modification reaction and obtain a conjugated diene polymer.

The order of the hydrogenation step and the modification step is not particularly limited. That is, the order may be polymerization step, hydrogenation step, and modification step, or polymerization step, modification step, and hydrogenation step. From the viewpoint of more easily obtaining the above-mentioned conjugated diene-based polymer, the order is preferably polymerization step, hydrogenation step, and modification step. Furthermore, the modification step may be performed in parallel with the polymerization step, as described below.

(Polymerization process)
The polymerization step is, for example, a step of polymerizing a conjugated diene compound and a vinyl aromatic compound in an organic solvent using an organic alkali metal compound as a polymerization initiator to obtain a random copolymer and/or a block copolymer.

The polymerization method may be batch polymerization, continuous polymerization, or a combination of these. From the perspective of maintaining a consistent size of the dispersed phase in the all-solid-state battery binder containing the conjugated diene-based polymer, which affects impact resistance and toughness, it is preferable to use a batch polymerization method, which results in a narrow molecular weight distribution.

The reaction temperature in the polymerization step may be 0°C or higher and 180°C or lower. From the viewpoint of more easily obtaining the conjugated diene-based polymer of this embodiment, the reaction temperature is preferably 20°C or higher and 160°C or lower, and more preferably 30°C or higher and 150°C or lower.

The reaction time in the polymerization step varies depending on the target polymer, but may be within 48 hours. From the viewpoint of more easily obtaining the conjugated diene-based polymer of this embodiment, the reaction time is preferably 0.1 to 10 hours. From the viewpoint of obtaining a conjugated diene-based polymer having a narrow molecular weight distribution and high strength, the reaction time is more preferably 0.5 to 5 hours.

The atmosphere of the polymerization system during the polymerization step is not particularly limited, as long as it is within a pressure range sufficient to maintain the nitrogen and solvent in a liquid phase. It is preferable that the polymerization system be free of impurities that may inactivate the polymerization initiator and living polymer, such as water, oxygen, and carbon dioxide.

Furthermore, at the end of the polymerization step, a required amount of a bifunctional or higher coupling agent may be added to carry out a coupling reaction. Bifunctional coupling agents may be any known agent and are not particularly limited. Examples include alkoxysilane compounds such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, trichloromethoxysilane, and trichloroethoxysilane; dihalogen compounds such as dichloroethane, dibromoethane, dimethyldichlorosilane, and dimethyldibromosilane; and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalates.

Furthermore, the tri- or higher functional polyfunctional coupling agent can be any known one, and is not particularly limited. Examples include tri- or higher hydric polyalcohols, epoxidized soybean oil, diglycidyl bisphenol A, polyvalent epoxy compounds such as 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane, halogenated silicon compounds represented by the general formula R ₄ -nSiX _n (where R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride and bromides thereof, and halogenated tin compounds represented by the general formula R ₄ -nSnX _n (where R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

The organic solvent is not particularly limited, but examples include aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcyclopentane; and aromatic hydrocarbons such as benzene, xylene, toluene, and ethylbenzene.

The organic alkali metal compound used as the polymerization initiator is preferably an organic lithium compound. The organic lithium compound is not particularly limited, but examples include organic monolithium compounds, organic dilithium compounds, and organic polylithium compounds.

Organolithium compounds are not particularly limited, but examples include ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, hexamethylenedilithium, butadienyllithium, isopropenyldilithium, and lithium piperidide. When an organolithium compound containing a nitrogen atom, such as lithium piperidide, is used as a polymerization initiator, a conjugated diene polymer containing a nitrogen atom is obtained.

These polymerization initiators may be used alone or in combination of two or more. Among these, n-butyllithium, sec-butyllithium, and lithium piperidide are preferred polymerization initiators from the viewpoint of improving polymerization activity.

The amount of organic alkali metal compound used as a polymerization initiator depends on the molecular weight of the desired conjugated diene polymer, but is typically in the range of 0.01 phm to 1.5 phm (here, phm indicates parts by mass per 100 parts by mass of monomer; the same applies below), more preferably in the range of 0.02 phm to 0.3 phm, and even more preferably in the range of 0.03 phm to 0.2 phm.

The vinyl bond content of conjugated diene polymers can be controlled by adding Lewis bases, such as ethers and amines, as vinyl bond content regulators (hereinafter referred to as "vinylating agents"). The amount of vinylating agent used can also be adjusted depending on the desired vinyl bond content.

Vinylating agents are not particularly limited, but examples include ether compounds and tertiary amine compounds.

Ether compounds are not particularly limited, but examples include linear ether compounds and cyclic ether compounds.

Straight-chain ether compounds include, but are not limited to, dialkyl ether compounds of ethylene glycol such as dimethyl ether, diethyl ether, diphenyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether, as well as dialkyl ether compounds of diethylene glycol such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether.

Cyclic ether compounds are not particularly limited, but examples include alkyl ethers such as tetrahydrofuran, dioxane, 2,5-dimethyloxolane, 2,2,5,5-tetramethyloxolane, 2,2-bis(2-oxolanyl)propane, and furfuryl alcohol.

Tertiary amine compounds are not particularly limited, but examples include trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N",N"-pentamethylethylenetriamine, N,N'-dioctyl-p-phenylenediamine, pyridine, tetramethylpropanediamine, and bis[2-(N,N-dimethylamino)ethyl]ether.

The tertiary amine compound is preferably a compound having two amines. Among these, the tertiary amine compound is more preferably a compound having an intramolecularly symmetric structure, and more preferably N,N,N',N'-tetramethylethylenediamine, bis[2-(N,N-dimethylamino)ethyl]ether, or 1,2-dipiperidinoethane.
These vinylating agents may be used alone or in combination of two or more.

In the polymerization process, a conjugated diene monomer may be polymerized alone, or a conjugated diene monomer may be polymerized with a vinyl aromatic monomer in the presence of an alkali metal alkoxide in addition to the vinylating agent and organolithium compound described above.

Here, alkali metal alkoxides are compounds represented by the general formula MOR (where M represents an alkali metal and R represents an alkyl group). The presence of alkali metal alkoxides in the polymerization process tends to make it easier to control the amount of vinyl bonds, molecular weight distribution, polymerization rate, block ratio, and other properties.

The alkali metal in the alkali metal alkoxide is preferably sodium or potassium, as this allows for a high vinyl bond content, narrow molecular weight distribution, high polymerization reaction rate, and high block rate to be obtained.

The alkali metal alkoxide is not particularly limited, but examples include sodium alkoxides, lithium alkoxides, and potassium alkoxides having an alkyl group with 2 to 12 carbon atoms. Preferred alkali metal alkoxides are sodium alkoxides and potassium alkoxides having an alkyl group with 3 to 6 carbon atoms, and more preferred are sodium t-butoxide, sodium t-pentoxide, potassium t-butoxide, and potassium t-pentoxide. Of these, sodium t-butoxide and sodium t-pentoxide are even more preferred.

(Hydrogenation step)
The hydrogenation step is a step of hydrogenating a conjugated diene polymer or a conjugated diene polymer. The hydrogenation method in the hydrogenation step is not particularly limited, and examples thereof include a method in which hydrogen gas is supplied to the conjugated diene polymer obtained in the polymerization step in the presence of a hydrogenation catalyst to hydrogenate it. When the method for producing a conjugated diene polymer includes such a hydrogenation step, residual double bonds in the conjugated diene monomer units are hydrogenated, and a more thermally stable hydrogenated conjugated diene polymer can be obtained.

The hydrogenation rate can be controlled, for example, by the amount of catalyst used during hydrogenation and the supply of hydrogen gas (hereinafter also referred to as "feed"). The hydrogenation rate can also be controlled, for example, by the amount of catalyst used during hydrogenation, the amount of hydrogen gas supplied, the pressure, the temperature, etc. The hydrogenation step is preferably carried out after the conjugated diene polymer production reaction in the polymerization step has stopped.

After the hydrogenation reaction is complete, a stabilizer may be added. There are no particular limitations on the stabilizer, but examples include octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate.

If necessary, the solution of conjugated diene polymer obtained as described above can be subjected to removal of catalyst residues and the conjugated diene polymer can be separated from the solvent.

Methods for separating the solvent include, for example, adding a polar solvent such as acetone or alcohol, which is a poor solvent for the hydrogenated copolymer, to the reaction solution after hydrogenation to precipitate and recover the polymer; pouring the reaction solution into hot water with stirring and removing the solvent by steam stripping; or directly heating the polymer solution to distill off the solvent. When poured into hot water, moisture becomes mixed into the polymer, so moisture can also be removed by a heating extrusion process or other method. Various stabilizers, such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers, can be added to the hydrogenated copolymer.

(Modification step)
The modification step is not particularly limited as long as it is a step of obtaining a conjugated diene polymer having a modifying group, and is, for example, a step of obtaining a conjugated diene polymer by reacting a conjugated diene polymer and/or a hydrogenated conjugated diene polymer with a modifying agent, whereby the obtained conjugated diene polymer has a modifying group.

The modification step may be performed in parallel with the polymerization step described above. Such modification reaction methods are not particularly limited, but include, for example, a method using a polymerization initiator having a binding group for the components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector, in the polymerization reaction in the polymerization step; and a method using an unsaturated monomer having a binding group for the components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector, in the polymerization reaction in the polymerization step. Another modification reaction method may involve adding a modifier that forms or contains a binding group for the components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector, to the living end of the conjugated diene polymer obtained by the polymerization reaction in the polymerization step.

The position at which the modifying group is introduced into a conjugated diene polymer is not particularly limited. For example, it may be at the end of the conjugated diene polymer, or it may be arranged in a block, random, or tapered configuration along part of the main chain of the conjugated diene polymer. To introduce the modifying group quantitatively and with high regioselectivity, it is preferable to copolymerize a monomer having the modifying group or a monomer to which the modifying group can be introduced in a subsequent process, or to introduce the modifying group into the polymer end. The concentration of the modifying group can be controlled depending on the amount of monomer having the modifying group, the amount of monomer to which the modifying group can be introduced in a subsequent process, or the amount of modifying agent reacted with the polymer end. Furthermore, when reacting the polymer end with a modifying agent, the amount of the modifying group can be reduced by increasing the molecular weight of the polymer and reducing the number of polymer ends. Introduction into the polymer end is suitable for introducing a small amount of the modifying group. Furthermore, a coupling agent having a modifying group or a modifying group precursor can also be used to introduce the modifying group into the polymer end. In this case, the coupling moiety will contain the modifying group.

To keep the amount of modifying groups to 3 mmol or less per 100 g of conjugated diene polymer, reacting the polymer terminal with a modifying agent is suitable, particularly for polymers with a molecular weight of 35,000 or more. When the polymer terminal reacts with the modifying agent in a 1:1 ratio, the amount of modifying groups can be controlled depending on the molecular weight: 2.9 mmol or less for a molecular weight of 35,000, 1.0 mmol or less for a molecular weight of 100,000, 0.5 mmol or less for a molecular weight of 200,000, 0.33 mmol or less for a molecular weight of 300,000, 0.2 mmol or less for a molecular weight of 500,000, and 0.14 mmol or less for a molecular weight of 700,000.

There are no particular restrictions on the amount of modifying groups as long as they are practically acceptable. However, if adhesive properties due to the interaction of the modifying groups with different materials are desired, the amount of modifying groups is preferably 0.10 mmol or more, and more preferably 0.15 mmol or more, per 100 g of conjugated diene polymer. Furthermore, from the perspective of conductive additive dispersibility, the amount of modifying groups is preferably 20 mmol or less, more preferably 5 mmol or less, even more preferably 1.5 mmol or less, and even more preferably 0.10 mmol or more and 0.50 mmol or less, per 100 g of conjugated diene polymer. In particular, for polymers with a molecular weight of 200,000 or more, a modification amount of 3.0 mmol or less can improve the balance between conductive additive dispersibility and adhesive properties due to the molecular weight entanglement effect in addition to the interaction between the modifying groups and the conductive additive.

The "polymerization initiator having a binding group for the components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector" is not particularly limited, but examples thereof include 3-lithio-1-[N,N-bis(trimethylsilyl)]aminopropane, 2-lithio-1-[N,N-bis(trimethylsilyl)]aminoethane, 3-lithio-2,2-dimethyl-1-[N,N-bis(trimethylsilyl)]aminopropane, 2,2,5,5-tetramethyl-1-(3-lithiopropyl)-1-aza-2,5-disilacyclopentane, 2,2,5, 5-tetramethyl-1-(3-lithio-2,2-dimethyl-propyl)-1-aza-2,5-disilacyclopentane, 2,2,5,5-tetramethyl-1-(2-lithioethyl)-1-aza-2,5-disilacyclopentane, 3-lithio-1-[N-(tert-butyl-dimethylsilyl)-N-trimethylsilyl]aminopropane, 3-lithio-1-(N-methyl-N-trimethylsilyl)aminopropane, 3-lithio-1-(N-ethyl-N-trimethylsilyl)aminopropane, and lithium piperidide.

Examples of "unsaturated monomers having binding groups for the components of the electrode active material layer or the solid electrolyte, or adhesive groups for the current collector" include, but are not limited to, p-[N,N-bis(trimethylsilyl)amino]styrene, p-[N,N-bis(trimethylsilyl)aminomethyl]styrene, p-{2-[N,N-bis(trimethylsilyl)amino]ethyl}styrene, m-[N,N-bis(trimethylsilyl)amino]styrene, p-(N-methyl-N-trimethylsilylamino)styrene, and p-(N-methyl-N-trimethylsilylaminomethyl)styrene.

The "modifier that forms or contains binding groups for the components of the electrode active material layer or the solid electrolyte, or adhesive groups for the current collector" is not particularly limited, but examples include tetraglycidyl metaxylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, and N-methylpyrrolidone.

Another method for introducing a modifying group is to react (metallation reaction) a conjugated diene polymer with an organic alkali metal compound such as an organolithium compound to obtain a polymer with an organic alkali metal attached thereto, and then add the above-mentioned modifier to the polymer with the organic alkali metal attached thereto.

Another method for introducing a modifying group is, for example, grafting an atomic group having a binding group for the constituent components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector, onto a conjugated diene polymer.

Such a method may involve direct grafting onto a conjugated diene polymer, or it may involve reacting a conjugated diene polymer into which a primary modifying group has been introduced with an atomic group having a binding group for the constituent components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector (secondary modification).

The "atomic group having a binding group for the constituent components of the electrode active material layer or the solid electrolyte, or an adhesive group for the current collector" is not particularly limited, but examples thereof include molecular units containing α,β-unsaturated carboxylic acid or its derivatives. Examples of α,β-unsaturated carboxylic acids or derivatives thereof include maleic acid, halogenated maleic acid, itaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endo-cis-bicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid, and the like, and anhydrides of these dicarboxylic acids, acrylic acid, methacrylic acid, crotonic acid, and the like, and esters of these monocarboxylic acids (e.g., 2-hydroxyethyl acrylate, methyl methacrylate, glycidyl methacrylate, and 3-(trimethoxysilyl)propyl methacrylate), and alkoxysilane compounds (e.g., vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltributoxysilane, vinyldimethoxymethylsilane, vinyldiethoxyethylsilane, vinyldipropoxypropylsilane, and vinyldibutoxybutylsilane). Among these, acrylic acid, anhydride, glycidyl methacrylate, vinyltrimethoxysilane, and vinyltriethoxysilane are preferred, and from the viewpoint of further enhancing adhesiveness, maleic anhydride is more preferred.

The amount of molecular units containing an α,β-unsaturated carboxylic acid or a derivative thereof added is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the conjugated diene polymer. From the viewpoint of binding strength to the constituent components of the electrode active material layer, the solid electrolyte, etc., or adhesion to the current collector, the amount added is preferably 0.1 parts by mass or more. On the other hand, from the viewpoint of improving the fluidity of the all-solid-state battery binder containing the conjugated diene polymer, the amount added is preferably 20 parts by mass or less.

Grafting methods include, for example, reacting a radical initiator, a conjugated diene polymer, and a compound containing an α,β-unsaturated carboxylic acid or a derivative thereof in a solution containing these compounds; reacting a radical initiator, a conjugated diene polymer, and a compound containing an α,β-unsaturated carboxylic acid or a derivative thereof under heating and melting or while not melting; reacting a conjugated diene polymer and a compound containing an α,β-unsaturated carboxylic acid or a derivative thereof under heating and melting or while not melting; reacting a compound that reacts with both compounds containing an α,β-unsaturated carboxylic acid or a derivative thereof to form a bond with a conjugated diene polymer grafted with a compound containing an α,β-unsaturated carboxylic acid or a derivative thereof in a solution containing these compounds; and reacting a compound that reacts with both compounds containing an α,β-unsaturated carboxylic acid or a derivative thereof to form a bond with a conjugated diene polymer grafted with a compound containing an α,β-unsaturated carboxylic acid or a derivative thereof under heating and melting or while not melting. In either case, graft addition by ene addition without the use of a radical initiator may also be used.

Preferably, this is a method in which a radical initiator, a conjugated diene polymer, and a compound containing an α,β-unsaturated carboxylic acid group or a derivative thereof are reacted while heated and melted, while heated and unmelted, or in solution, and more preferably, while heated and melted. In any of the above preferred cases, graft addition by ene addition without using a radical initiator is also acceptable.

Methods for reacting a radical initiator, a conjugated diene polymer, and a compound containing an α,β-unsaturated carboxylic acid group or a derivative thereof under heating and melting include melt-kneading the components using a common mixer such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a co-kneader, or a multi-screw extruder. From the standpoints of cost and production stability, a method using a single-screw, twin-screw, or multi-screw extruder is preferred, and a method using a twin-screw extruder is more preferred.

The radical initiator, conjugated diene polymer, and compound containing an α,β-unsaturated carboxylic acid group or a derivative thereof may be dry-blended and added all at once, or each raw material may be added separately, or the same raw material may be added in multiple batches.

From the viewpoint of uniformly adding the compound containing an α,β-unsaturated carboxylic acid or a derivative thereof to the conjugated diene polymer, the screw rotation speed is preferably 50 rpm or more and 400 rpm or less, and more preferably 100 rpm or more and 350 rpm or less. Furthermore, from the viewpoint of suppressing resin deterioration due to shear and uniformly adding the compound containing an α,β-unsaturated carboxylic acid or a derivative thereof to the conjugated diene polymer, the screw rotation speed is preferably 150 rpm or more and 300 rpm or less.

The kneading temperature is not particularly limited as long as it is a temperature at which the conjugated diene polymer melts and at which radicals are generated from the radical initiator, but is preferably 100°C or higher and 350°C or lower. From the perspective of controlling the amount of compound containing an α,β-unsaturated carboxylic acid or a derivative thereof added and suppressing thermal degradation of the resin, the kneading temperature is more preferably 120°C or higher and 300°C or lower, and even more preferably 150°C or higher and 250°C or lower.

To prevent deactivation of radical active species by oxygen, the material may be melt-kneaded under an inert gas atmosphere such as nitrogen.

The amount of modifying groups in conjugated diene polymers is preferably low from the perspective of suppressing moisture absorption, as long as the adhesiveness, binding ability, volatility, and conductive additive dispersibility are sufficient. It is preferably 20 mmol or less per 100 g of polymer, more preferably 15 mmol or less, even more preferably 10 mmol or less, 4 mmmol or less, or 2 mmmol or less. In particular, for molecular weights of 200,000 or more, the amount is 15 mmol or less, even more preferably 10 mmol or less, 4 mmmol or less, or 2 mmmol or less. As the molecular weight increases, the degree of entanglement between polymers increases, and interactions between the modifying groups and the conductive additive can deteriorate the dispersibility of the conductive additive. Therefore, it is preferable to keep the amount of modification low while still maintaining adhesiveness, binding ability, and volatility. Among the above-mentioned modifying groups, a low amount of modifying groups is particularly preferred for functional groups with affinity for water molecules, such as acid anhydride groups, carboxyl groups, amino groups, epoxy groups, alkoxysilane groups, and hydroxyl groups. The conductive additive is mainly made of carbon, and since there are many functional groups such as COOH and OH on the surface, it is thought that there is an interaction with the conjugated diene polymer regardless of the type of conductive additive.

The radical initiator used in the graft addition is not particularly limited, but examples include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, and peroxydicarbonates. Among these, radical initiators whose one-minute half-life temperature is within the kneading temperature range are preferred. More preferably, it is a radical initiator having a one-minute half-life temperature of 150°C or higher and 250°C or lower. Examples of such radical initiators include 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylauric acid, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5- Examples of peroxyl groups include di(benzoylperoxy)hexane, t-butyl peroxyacetate, 2,2-di-(t-butylperoxy)butane, t-butyl peroxybenzoate, n-butyl-4,4-di-(t-butylperoxy)valerate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p-methane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.

From the viewpoint of improving compatibility with conjugated diene polymers, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 are preferred. Of these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 are more preferred.

The molar equivalent of the compound containing an α,β-unsaturated carboxylic acid or a derivative thereof relative to the radical initiator is preferably 300 molar equivalents or less, more preferably 200 molar equivalents or less, and even more preferably 100 molar equivalents or less. By having the molar equivalent within the above range, it is easier to add the compound containing an α,β-unsaturated carboxylic acid or a derivative thereof in an amount of more than 0 parts by mass up to approximately 10 parts by mass per 100 parts by mass of the conjugated diene polymer.

When a conjugated diene polymer having a primary modifying group is further modified with an atomic group that has adhesive properties to the constituent components of the electrode active material layer, the solid electrolyte, or the current collector, there are no particular restrictions on the reaction method, and known methods can be used. Examples include a method in which the primary conjugated diene polymer and the modifier are dry-blended, and then the components are melt-kneaded using a common mixer such as a Banbury mixer, single-screw extruder, twin-screw extruder, co-kneader, or multi-screw extruder; and a method in which the components are dissolved or dispersed in a solvent and then the solvent is removed by heating.

Of these, the melt-kneading method using an extruder is preferred from the standpoint of improving productivity and good kneading properties.

The shape of the conjugated diene polymer of this embodiment is not particularly limited, but examples include pellets, sheets, strands, chips, powder, and crumbs. After melt-kneading, the polymer may be directly molded into a product, or may be produced in chip, powder, or crumb form. From the perspective of the efficiency of removing moisture contained in the conjugated diene polymer, a shape with a large specific surface area is preferred, and crumbs and powder forms are preferred over pellets.

Pelletization methods include, for example, a method in which a conjugated diene polymer is extruded in the form of strands from a single- or twin-screw extruder and then cut underwater with a rotary blade installed in front of the die (e.g., underwater cutting); a method in which a conjugated diene polymer is extruded in the form of strands from a single- or twin-screw extruder, water- or air-cooled, and then cut with a strand cutter; and a method in which a conjugated diene polymer is melt-mixed in an open roll or Banbury mixer, molded into a sheet with a roll, cut into strips, and then cut into cubic pellets with a pelletizer. In the underwater cutting method, moisture is introduced onto the polymer surface, so moisture can be removed by subsequent processes such as centrifugal dehydration or pneumatic transport. Furthermore, in the strand cutter method, moisture can be removed by subsequent processes such as air blowing, suction-type draining, or pneumatic transport during the air-cooling process.

The size and shape of the pellets are not particularly limited, but from the perspective of preventing pellets from adhering to each other, pellets that are nearly spherical are preferable to cylindrical pellets obtained by cutting the strands perpendicular to their longitudinal axis, as this reduces the adhesive surface area between the pellets. Common methods for producing nearly spherical pellets include, for example, underwater cutting and center hot cutting.

Pellets of conjugated diene polymers may contain an anti-blocking agent to prevent pellet blocking.

The conjugated diene polymer may contain a phosphorus compound. The content of the phosphorus compound, calculated as phosphorus atoms, relative to the conjugated diene copolymer is preferably 10 ppm or more, more preferably 20 ppm or more, and even more preferably 50 ppm or more. The preferred upper limit is 250 ppm or less, more preferably 120 ppm or less.

The anti-blocking agent is not particularly limited, but examples include higher fatty acid metal salts, polyolefins, fatty acid amides, talc, and silica. Specific examples include calcium stearate, magnesium stearate, zinc stearate, polyethylene, polypropylene, ethylene bisstearylamide, talc, and amorphous silica. From the viewpoint of low bleeding, calcium stearate, magnesium stearate, zinc stearate, polyethylene, polypropylene, talc, and amorphous silica are preferred. From the viewpoint of slipperiness during hopper addition, calcium stearate, magnesium stearate, zinc stearate, polyethylene, polypropylene, and amorphous silica are more preferred. From the viewpoint of dustiness, polyethylene or amorphous silica is even more preferred, with amorphous silica being the most preferred.

From the viewpoint of the constituent components of the resulting electrode active material layer and adhesion to the solid electrolyte or current collector, calcium stearate, polyethylene, polypropylene, and ethylene bisstearylamide are preferred as anti-blocking agents.

The preferred amount of anti-blocking agent used is 500 ppm or more and 8000 ppm or less relative to the conjugated diene polymer. From the perspective of suppressing pellet blocking during long-term storage of conjugated diene polymer pellets and reducing the scattering of the anti-blocking agent when the conjugated diene polymer pellets are used, the amount of anti-blocking agent used is more preferably 1000 ppm or more and 7000 ppm or less relative to the conjugated diene polymer. The anti-blocking agent is preferably incorporated in a state where it adheres to the pellet surface, but may also be contained inside the pellet.

Conjugated diene polymers may also contain other additives, including, but not limited to, oils, fillers, heat stabilizers, UV absorbers, nucleating agents, antioxidants, weathering agents, light stabilizers, plasticizers, antistatic agents, flame retardants, slip agents, anti-fogging agents, lubricants, pigments, dyes, dispersants, copper inhibitors, neutralizing agents, bubble inhibitors, weld strength improvers, natural oils, synthetic oils, and waxes. Other elastomers and thermoplastic resins may also be used as additives in any proportion. These may be used alone or in combination of two or more.

[All-solid-state battery]
Next, an embodiment of an all-solid-state battery using the all-solid-state battery binder will be described. The all-solid-state battery of this embodiment includes at least one layer selected from the group consisting of a positive electrode layer containing the all-solid-state battery binder, a solid electrolyte layer containing the all-solid-state battery binder, and a negative electrode layer containing the all-solid-state battery binder.

Figure 1 is a schematic cross-sectional view showing an example of an all-solid-state battery according to this embodiment. This all-solid-state battery (all-solid-state battery) 100 includes a solid electrolyte layer 110, a positive electrode layer 140 and a negative electrode layer 150 sandwiching the solid electrolyte layer 110 from either side, a positive electrode current collector 160 (disposed on the outside of the positive electrode) and a negative electrode current collector 170 (disposed on the outside of the negative electrode) sandwiching the laminate, and a battery exterior 180 housing them.

In this embodiment, by using the above-mentioned all-solid-state battery binder, it is possible to produce all-solid-state batteries with reduced water content, thereby realizing all-solid-state batteries with high electrical capacity.

The amount of moisture contained in an all-solid-state battery is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Moisture may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment.

[Positive electrode]
The positive electrode has a positive electrode current collector and a positive electrode layer formed on the positive electrode current collector. The positive electrode layer contains a positive electrode active material and, as needed, may contain a conductive aid, an all-solid-state battery binder, an inorganic solid electrolyte for enhancing ionic conductivity, a polymer gel electrolyte, a polymer electrolyte, an additive, or the like.

The positive electrode active material can be any positive electrode active material used in general lithium-ion batteries, such as oxide active materials and sulfide active materials.

Specifically, layered rock salt type positive electrode materials include Li-Co composite oxides such as LiCoO ₂ and Li-Ni composite oxides such as LiNiO ₂ , nickel-based compounds derived from these, such as LiNi(Co,Al)O ₂ , ternary compounds such as LiNi _1/3 Mn _1/3 Co _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂ , nickel-manganese compounds such as LiNi _0.5 Mn _0.5 O ₂ , lithium-excess compounds such as Li ₂ MnO ₃ -LiMO ₂ (M = Co, Ni, Mn), spinel type positive electrode materials such as LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ , and olivine type positive electrode material such as LiFeO _2. , LiCoPO ₄ , LiNiPO ₄ , LiFePO _{4 ,} LiMnPO ₄ , Li ₂ MSiO ₄ (M is a transition metal), LiMPO ₄ F (M is a transition metal), and high-capacity positive electrode materials such as vanadium oxide and sulfur-based positive electrode materials can be used. The positive electrode active material may be used alone or in combination of two or more.

The positive electrode is not particularly limited as long as it functions as a positive electrode for a lithium-ion secondary battery, and can be obtained, for example, as follows.

First, the cathode active material is mixed with other components (e.g., conductive additives, binders, etc.) as needed to form a cathode mixture, which is dispersed in a solvent to prepare a cathode mixture-containing slurry. This cathode mixture-containing slurry is then applied to a cathode current collector (substrate) and dried to form a cathode layer, which is then further compressed as needed to adjust the thickness, thereby producing the cathode.

The solids concentration in the positive electrode mixture-containing slurry is not particularly limited, but is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.

The positive electrode current collector is made of a metal foil, such as aluminum, stainless steel, gold, platinum, titanium, tin, copper, or zinc. These materials may also be coated with carbon, or processed into a mesh.

If necessary, a method can be used in which the spaces between the particles are filled with a lithium-ion conductive material to maintain lithium-ion conductivity with the solid electrolyte. Examples of the lithium-ion conductive material include amorphous lithium-ion conductive materials, such as polymer electrolytes and amorphous inorganic compounds with lithium ion conductivity.

The amount of moisture contained in the positive electrode layer is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Moisture may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment.

[Negative electrode]
The negative electrode has a negative electrode current collector and a negative electrode layer formed on the negative electrode current collector. The negative electrode layer contains a negative electrode active material and, as needed, may contain a conductive aid, an all-solid-state battery binder, an inorganic solid electrolyte for enhancing ionic conductivity, a polymer gel electrolyte, a polymer electrolyte, an additive, or the like.

The negative electrode preferably contains, as the negative electrode active material, one or more materials selected from the group consisting of materials capable of absorbing and releasing lithium ions and metallic lithium. Examples of such materials include metallic lithium, materials containing elements capable of forming an alloy with lithium, and other metallic materials, as well as carbon materials such as amorphous carbon (hard carbon), artificial graphite, natural graphite, graphite, pyrolytic carbon, coke, glassy carbon, fired organic polymer compounds, mesocarbon microbeads, carbon fiber, activated carbon, graphite, carbon colloid, and carbon black.

Among these, examples of coke include pitch coke, needle coke, and petroleum coke. Calcined organic polymer compounds are made by calcining polymer materials such as phenolic resin and furan resin at an appropriate temperature to carbonize them.

In addition to carbon, the carbon material may also contain heterogeneous compounds containing O, B, P, N, S, SiC, BC, etc. The content of the heterogeneous compounds is preferably 0 to 10 mass% of the total negative electrode active material.

The metallic material capable of forming an alloy with lithium may be a simple substance, alloy, or compound of a metal or semimetal, or may have one or more of these phases at least in part. Alternatively, known materials such as _oxide active materials such as SiOx and _Li4Ti5O12 may be used. Furthermore, one or _more of the above-mentioned negative electrode active materials may be used in combination.

The number average particle diameter (primary particle diameter) of the negative electrode active material is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm.

A negative electrode can be obtained, for example, as follows. First, the negative electrode active material is mixed with other components (e.g., conductive additives, binders, etc.) as needed to form a negative electrode mixture, which is dispersed in a solvent to prepare a negative electrode mixture-containing slurry. Next, this negative electrode mixture-containing slurry is applied to a negative electrode current collector (substrate) and dried to form a negative electrode layer. Further, pressure is applied as needed to adjust the thickness, thereby producing the negative electrode.

Here, the solids concentration in the negative electrode mixture-containing slurry is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass. The negative electrode current collector is made of a metal foil such as copper, nickel, stainless steel, gold, platinum, titanium, tin, or zinc.

If necessary, to maintain lithium ion conductivity with the solid electrolyte, a method can be used in which the spaces between the particles are filled with a lithium ion conductive material. Examples of the lithium ion conductive material include amorphous lithium ion conductive materials, such as polymer electrolytes and amorphous inorganic compounds with lithium ion conductivity.

The amount of moisture contained in the negative electrode layer is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Moisture may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment.

〔slurry〕
The slurry of the present embodiment that can be used as the positive electrode mixture-containing slurry or the negative electrode mixture-containing slurry contains the all-solid-state battery binder, and may also contain a conductive additive, a solvent, the positive electrode active material or the negative electrode active material, etc., as necessary.

The slurry of this embodiment preferably does not contain water, and the water content of the slurry is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. The water contained in the all-solid-state battery binder may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment.

(Conductive additive)
The conductive additive of this embodiment is not particularly limited as long as it has electronic conductivity. Examples include graphite; carbon black, such as acetylene black and ketjen black; and carbon fibers, such as vapor-grown carbon fibers and carbon nanotubes. Among these, carbon black is preferred. The number-average particle size (primary particle size) of the conductive additive used in the positive electrode is preferably 10 nm to 10 μm, more preferably 20 nm to 1 μm. The number-average particle size (primary particle size) of the conductive additive used in the negative electrode is preferably 0.1 μm to 100 μm, more preferably 1 μm to 10 μm. These additives may be used alone or in combination of two or more. The use of a conductive additive can ensure an electronic conduction path in each electrode layer, reduce the internal resistance of the all-solid-state battery, and increase the current capacity, thereby improving the charge/discharge characteristics of the all-solid-state battery. By selecting the modifying group of the all-solid-state battery binder to match the functional group on the surface of the conductive additive, dispersibility can be controlled through interaction. Since carboxyl groups and hydroxyl groups exist on the surface of the carbon-based conductive additive, the mutual carboxyl groups, hydroxyl groups and amino groups are preferred due to the interaction caused by hydrogen bonding.

Examples of carbon black include oil furnace black and gas furnace black, which are produced by the furnace method (incomplete combustion method), and acetylene black and thermal black, which are produced by the thermal method (thermal decomposition method). Of these, oil furnace black and acetylene black are preferred from the perspective of electronic conductivity. Examples of oil furnace black include Ketjenblack (a product manufactured by Lion Specialty Chemicals Co., Ltd.), and examples of acetylene black include Denka Black (registered trademark) (a product manufactured by Denka Company Ltd.).

(binder)
The binder of this embodiment is a conjugated diene polymer. Although not particularly limited, polymer materials other than conjugated diene polymers can also be used in combination. Specific examples include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, styrene-butadiene rubber, and fluororubber. These may have functional groups due to modification. The binder may be used alone or in combination of two or more.

There are no particular restrictions on the content of the all-solid-state battery binder contained in the positive electrode, but from the standpoint of ionic and electronic conductivity, it is preferably 10 wt% or less, more preferably 5 wt% or less, even more preferably 3 wt% or less, and particularly preferably 1 wt% or less, of the total weight of the positive electrode (excluding the current collector) taken as 100 wt%.

In addition, there are no particular restrictions on the content of the all-solid-state battery binder contained in the negative electrode, but from the standpoint of ionic conductivity and electronic conductivity, it is preferably 10 wt% or less, more preferably 5 wt% or less, even more preferably 3 wt% or less, and particularly preferably 1 wt% or less, of the total weight of the negative electrode (excluding the current collector) taken as 100 wt%.

In addition, there are no particular restrictions on the content of the all-solid-state battery binder contained in the solid electrolyte layer, but from the standpoint of ionic conductivity and electronic conductivity, it is preferably 10 wt% or less, more preferably 5 wt% or less, even more preferably 3 wt% or less, and particularly preferably 1 wt% or less, when the total weight of the solid electrolyte layer is taken as 100 wt%.

The binder for all-solid-state batteries may be distributed uniformly or unevenly in each layer, or may be distributed with a gradient. It can also be used to bond the interfaces of each layer, if necessary.

In all-solid-state batteries, there are no particular restrictions on the concentration distribution of the conductive additive contained in the positive electrode layer. However, from the perspective of electronic conductivity, the concentration of the conductive additive near the positive electrode current collector is preferably higher than that near the solid electrolyte layer. During the charge/discharge process of an all-solid-state battery, the entire current in the positive electrode layer is concentrated near the positive electrode current collector. Therefore, by increasing the concentration of the conductive additive near the positive electrode current collector, it is possible to remove bottlenecks in the electronic conduction path in the positive electrode layer, improving the charge/discharge load characteristics and cycle life characteristics of the battery.

In the all-solid-state battery according to this embodiment, the concentration of the conductive additive contained in the positive electrode layer is higher near the positive electrode current collector than near the solid electrolyte layer, and preferably the concentration of the conductive additive near the positive electrode current collector is at least 10 times the concentration of the conductive additive near the solid electrolyte layer. During charging and discharging of the all-solid-state battery, electron conduction is greater than lithium ion conduction near the positive electrode current collector. Therefore, it is preferable to increase the concentration of the conductive additive near the positive electrode current collector. This improves the electronic conductivity of the positive electrode layer during charging and discharging, resulting in good charge and discharge characteristics.

In addition, in the all-solid-state battery according to this embodiment, the concentration distribution of the conductive additive contained in the negative electrode layer is not particularly limited, but from the viewpoint of electronic conductivity, the concentration of the conductive additive near the negative electrode current collector is preferably higher than that near the solid electrolyte layer. During the charge/discharge process of an all-solid-state battery, the entire current of the negative electrode layer is concentrated near the negative electrode current collector. Therefore, by increasing the concentration of the conductive additive near the negative electrode current collector, it is possible to remove the bottleneck in the electronic conduction path of the negative electrode layer, improving the charge/discharge load characteristics and cycle life characteristics of the battery.

Furthermore, similar to the positive electrode layer, during charging and discharging of an all-solid-state battery, electron conduction is greater than lithium ion conduction near the negative electrode current collector. Therefore, in the negative electrode layer of this embodiment, the concentration of conductive additive near the negative electrode current collector is preferably higher than that near the solid electrolyte layer, and preferably the concentration of conductive additive near the negative electrode current collector is at least eight times the concentration of conductive additive near the solid electrolyte layer. This improves the electronic conductivity of the negative electrode layer during charging and discharging, resulting in good charge and discharge characteristics.

(solvent)
The solvent of this embodiment is not particularly limited as long as it does not adversely affect the performance of the solid electrolyte. For example, a non-polar solvent having low hydrophilicity can be used. Examples of the non-polar solvent include hydrocarbon solvents such as heptane, xylene, toluene, and hexane, or a combination thereof. From the viewpoint of suppressing decomposition of the solid electrolyte, a hydrocarbon organic solvent that has been dehydrated to reduce its water content is preferably used. Furthermore, from the viewpoint of productivity, a non-polar solvent having a boiling point of 100°C or higher and a melting point of 0°C or lower at atmospheric pressure is preferred, and more preferably a non-polar solvent having a boiling point of 150°C or higher and a melting point of -20°C or lower at atmospheric pressure is preferred.

[Solid electrolyte layer]
The solid electrolyte layer of the present embodiment includes an ion-conductive solid electrolyte and, if necessary, an all-solid-state battery binder. The ion-conductive solid electrolyte is not particularly limited as long as it can be used in all-solid-state batteries, and examples thereof include sulfide-based solid electrolytes and oxide-based solid electrolytes.

Examples of sulfide-based solid electrolytes include sulfide-based amorphous solid electrolytes such as Li ₂ S—SiS ₂ , LiI—Li ₂ S—SiS ₂ , LiI—Li ₂ S—P ₂ S ₅ , LiI—Li ₂ SP ₂ O ₅ , LiI—Li ₃ PO ₄ —P ₂ S ₅ , and Li ₂ S—P ₂ S ₅ ; sulfide-based glass ceramic solid electrolytes such as those containing Li ₂ S and P ₂ S ₅ ; and Thio-LISICON-based solid electrolytes such as Li _3.25 Ge _0.25 P _0.75 S _{4 and} Li ₁₀ GeP ₂ S ₁₂ .

Examples of oxide-based solid electrolytes include crystalline oxide-based solid electrolytes such as γ-LiPO4 _- type oxides, _inverse fluorite-type oxides, NASICON-type oxides such _{as Li1.3Al0.3Ti0.7} ( _PO4 ) ₃ , _perovskite -type _{Li0.5La0.5TiO3} , _{and garnet-type Li7La3Zr2O12. Examples of amorphous oxide-based solid electrolytes include LiPON, Li2O-B2O3-P2O5 , and Li2O - SiO2 . These may be used} alone or in combination of two or more.

In particular, from the perspective of balancing performance and manufacturing, it is preferable to use a sulfide-based solid electrolyte.

The shape of the solid electrolyte is not particularly limited and may be in the form of particles or thin film. In the case of particles, the average particle diameter is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 40 μm or less. As the particles become finer, the packing density improves and good ionic conductivity is obtained. Furthermore, from the viewpoint of the physical strength of the solid electrolyte layer and prevention of short circuits, the particle diameter is preferably 0.1 μm or more.

Since solid electrolytes easily react with moisture and decompose, the amount of moisture contained in the solid electrolyte layer is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, even more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Moisture may be removed by drying in a dryer at normal or reduced pressure, or by storing in a dehumidified environment.

The method for forming the solid electrolyte layer is not particularly limited. For example, it can be obtained by press-molding a mixture containing a solid electrolyte or, if necessary, other components such as an all-solid-state battery binder. Alternatively, a slurry containing a solid electrolyte or, if necessary, a mixture containing other components such as an all-solid-state battery binder is applied to a substrate, dried, and, if necessary, pressed to adjust the thickness, and then peeled off from the substrate to obtain a solid electrolyte layer.

[Battery Construction]
The all-solid-state battery of this embodiment is fabricated by a known method using the above-described positive electrode, negative electrode, and solid electrolyte layer. For example, the electrode stack may be fabricated as a laminate in which a positive electrode, a negative electrode, and a solid electrolyte layer are interposed, or as a multilayer laminate in which an electron conductor is interposed between multiple positive electrodes and negative electrodes that are alternately stacked. The electrode stack is then housed in a battery case (exterior) and sealed, thereby fabricating the all-solid-state battery of this embodiment.

During battery fabrication, a pressure of 0.1 to 4000 kgf/ ^cm2 is preferably applied to the opposing surfaces of the positive and negative electrodes, more preferably 0.1 to 100 kgf/ ^cm2 , and most preferably 0.5 to ¹⁵ kgf/cm2. A pressure of 0.1 kgf/ ^cm2 or higher improves the contact between the electrode active material and the solid electrolyte, improving battery performance. A pressure of 4000 kgf/cm2 or ^lower can prevent short circuits caused by internal battery damage. While the battery can be operated while maintaining the pressurized state during battery fabrication, it can also be operated without pressure if there are no problems with the charge/discharge characteristics.

The shape of the all-solid-state battery of this embodiment is not particularly limited, and suitable shapes include, for example, cylindrical, elliptical, rectangular, button, coin, flat, and laminate shapes. Furthermore, the solid electrolyte of this embodiment can be applied not only to the all-solid-state battery described above, but also to other batteries.

The above describes the embodiments for implementing the present invention, but the present invention is not limited to the above embodiments. The present invention can be modified in various ways without departing from the spirit of the invention.

Below, this embodiment will be explained in detail using specific examples and comparative examples, but this embodiment is not limited in any way by the following examples and comparative examples.

The structures of the conjugated diene polymers and the methods for measuring and evaluating the physical properties of the conjugated diene polymer binders in the examples and comparative examples are shown below.

[Measurement and Evaluation of the Structure of Conjugated Diene Polymer and the Physical Properties of Conjugated Diene Polymer Binder]
(1) Content of each polymer block in conjugated diene polymer Using the following formula, the content of each polymer block in the conjugated diene polymer before hydrogenation was calculated, and the content of each polymer block in the conjugated diene polymer was calculated.
Content of each block in the conjugated diene polymer before hydrogenation = [(total amount of monomers fed in each step)/(total amount of monomers)] x 100 (mass%)

However, it was confirmed that the polymerization rate of butadiene monomer and styrene monomer was 100% at each step of the polymerization process of the conjugated diene polymer as follows.

Approximately 20 mL of the polymer solution sampled at each step of the polymerization process was injected into a 100 mL bottle containing 0.50 mL of n-propylbenzene (used as an internal standard) and approximately 20 mL of toluene. Each sample was measured using a gas chromatograph (Shimadzu Corporation: GC-14B (product name)) equipped with a backed column loaded with Apiezon grease. The amount of residual monomer in the polymer solution was determined using the previously obtained calibration curves for butadiene monomer and styrene monomer, confirming the absence of residual monomer.

The temperature conditions for gas chromatography measurements were as follows: the polymerization rate of butadiene was kept constant at 90°C, and the polymerization rate of styrene was measured by heating from 90°C (10-minute hold) to 150°C (10°C/min).

(2) Amount of vinyl bonds in conjugated diene polymer before hydrogenation The amount of vinyl bonds in conjugated diene polymer before hydrogenation was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using a polymer solution sampled at each step of the polymerization process of the conjugated diene polymer.

Measurement was carried out under the following conditions using an ECS400 (manufactured by JEOL) as a measuring instrument, deuterated chloroform as a solvent, and a sample concentration of 50 mg/mL: The amount of vinyl bonds was calculated from the signal ratio between 1,4-bonds and 1,2-bonds after determining the integrated values of signals attributed to 1,4-bonds and 1,2-bonds in the conjugated diene monomer units.
(Measurement conditions)
Observation frequency: 400MHz
Chemical shift reference: tetramethylsilane Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45°
Measurement temperature: 26℃

(3) Hydrogenation rate of conjugated diene polymer The hydrogenation rate of unsaturated bonds based on conjugated diene monomer units of a conjugated diene polymer was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using the conjugated diene polymer before and after hydrogenation. The measurement conditions and the method of processing the measurement data were the same as those in (2) above.

The hydrogenation rate was calculated from the signal ratio obtained by integrating the signals derived from double bonds at 4.5 to 5.5 ppm and the signals derived from hydrogenated conjugated dienes.

(4) Sum of butylene and propylene contents of conjugated diene polymer The sum of the butylene and propylene contents relative to 100 mol% of the total of conjugated diene monomer units in the conjugated diene polymer was measured by proton nuclear magnetic resonance ( ¹ H-NMR) using the hydrogenated conjugated diene polymer. The measurement conditions and the method of processing the measurement data were the same as those in (2) and (3) above.

The amount of butylene was calculated from the signal ratio obtained by integrating the signals derived from all conjugated diene monomer units in the conjugated diene polymer after hydrogenation and the signals derived from the butylene portion (hydrogenated 1,2-bonds) in the spectrum from 0 to 2.0 ppm.

(5) Styrene Content of Conjugated Diene Polymer Using a copolymer before hydrogenation, the styrene content was calculated from the absorption intensity at 262 nm using an ultraviolet spectrophotometer (Shimadzu Corporation, UV-2450). Since the content of all vinyl aromatic compound monomer units does not change significantly before and after hydrogenation, the content of all vinyl aromatic compound monomer units (styrene monomer units) obtained for the copolymer before hydrogenation was taken as the content of all vinyl aromatic compound monomer units (total styrene content) of the hydrogenated copolymer.

(6) Content of polymer block mainly composed of styrene unit in conjugated diene polymer (Os value)
Using an unmodified conjugated diene polymer before hydrogenation, the content of polymer blocks mainly composed of styrene units in the conjugated diene polymer (hereinafter also referred to as "Os value") was measured by the osmium tetroxide decomposition method described in I. M. KOLTHOFF, et al., J. Polym. Soi. 1, 429 (1946).

A 0.1 g/125 mL tertiary butanol solution of osmic acid was used to decompose the unmodified conjugated diene polymer before hydrogenation.

(7) Weight-average molecular weight and molecular weight distribution of conjugated diene polymer and conjugated diene polymer The weight-average molecular weight and molecular weight distribution of the conjugated diene polymer and conjugated diene polymer were measured using GPC (GPC apparatus: HLC8220 (product name, manufactured by Tosoh Corporation), column: 4.6 mm x 30 cm TSKgelSUPER-HZM-N (product name, manufactured by Sigma-Aldrich)). Tetrahydrofuran was used as the solvent.

The weight-average molecular weight was determined from the peaks in the chromatogram based on a calibration curve obtained using commercially available standard polystyrene. When there are multiple peaks in the chromatogram, the weight-average molecular weight was calculated from the molecular weight of each peak and the composition ratio of each peak (calculated from the area ratio of each peak in the chromatogram). Conjugated diene polymers may adsorb to the column due to interactions between the modifying group and the column; in such cases, the molecular weight of the unadsorbed portion or the copolymer before modification is measured.

The molecular weight distribution was calculated from the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Conjugated diene polymers may adsorb to the column due to interactions between the modifying groups and the column; in such cases, the molecular weight of the non-adsorbed portion is measured.

(8) Acid Anhydride Addition Amount of Conjugated Diene Polymer The acid anhydride addition amount in the conjugated diene polymer was calculated by dissolving the conjugated diene polymer after modification with the acid anhydride in toluene and titrating it with a methanol solution of sodium methoxide having a factor of 1±0.05.

(9) Modification Ratio of Amine-Terminated Conjugated Diene Polymer Using the property of adsorption of modified components to a GPC column packed with silica gel, a sample solution containing a conjugated diene polymer and a low-molecular-weight internal standard polystyrene was compared between the ratio of the conjugated diene polymer to the standard polystyrene in the chromatogram measured in (6) above and the ratio of the conjugated diene polymer to the standard polystyrene in the chromatogram measured using a silica-based column GPC [apparatus: LC-10 (manufactured by Shimadzu Corporation), column: Zorbax (manufactured by DuPont)], and the amount of adsorption to the silica-based column was determined from the difference therebetween, and this ratio was taken as the modification ratio. It was calculated using the following formula.

a: Area (%) of the total polymer measured using a polystyrene gel (PLgel)
b: Area (%) of low molecular weight internal standard PS measured on polystyrene gel (PLgel)
c: Area (%) of total polymer measured on a silica column (Zorbax)
d: Area (%) of low molecular weight internal standard PS measured on a silica-based column (Zorbax)

(10) Toluene-insoluble Content 1 g of a conjugated diene polymer was placed in a test tube-shaped container made of a 200-mesh wire netting, and the container was immersed in 100 mL of toluene and shaken for 24 hours or more using a shaker. When the polymer was sufficiently dissolved, the container was removed, washed with toluene from the outside, and dried in a vacuum dryer for 12 hours at 60° C. Using the weight W1 of the resulting container, the weight W0 of the container before the test, and the weighed value P of the conjugated diene polymer, the toluene-insoluble content was calculated according to the following formula:
Insoluble fraction (%) = (W1-W0)/P×100

(11) Loose bulk density and compressibility: Evaluation was performed using a Powder Tester PT-X (manufactured by Hosokawa Micron Corporation). A conjugated diene polymer was added to a 100 ^cm3 bulk density measurement vessel so that it exceeded the top surface, and the excess was removed. The loose bulk density was calculated from the weight at that time and the volume of the vessel. Furthermore, the addition of the conjugated diene polymer to a vessel so that it exceeded the top surface and tapping were repeated 180 times to calculate the packed bulk density. The compressibility was evaluated using the following formula:
Compressibility = (tight bulk density - loose bulk density) / tight bulk density x 100

(12) Solvent Solubility When a Stirrer is Used 10 g of a conjugated diene polymer and toluene were placed in 100 mL of toluene in a glass screw vial having an internal volume of 200 mL, and the mixture was stirred with a magnetic stirrer for 5 minutes, after which the solubility was evaluated.
(Evaluation criteria)
○: No residual dissolution △: 0% to less than 20% residual dissolution ×: 20% or more residual dissolution

(13) Thermal Stability The polymer was dried at 100° C. for 48 hours, and the thermal stability was evaluated from the decrease in peak height in the differential molecular weight distribution of the GPC chart before and after heating.
(Evaluation criteria)
○: Less than 0.1% △: 0.1% to less than 0.3%
×: 0.3% or more

(14) Feed Stability Assuming material supply, the error range relative to the set value when discharging an all-solid-state battery binder using a single-axis screw feeder was evaluated. The all-solid-state battery binder was discharged from the feeder at a set value of 5 kg/h for 5 minutes, and the sum of the absolute values of the errors from the set value recorded every 3 seconds was averaged by the number of records, and the percentage of the error relative to the set value was evaluated.
(Evaluation criteria)
○: Less than 0.5% △: 0.5% or more but less than 1.0%
×: 1.0% or more

(15) Interfacial peel strength (adhesion) between conjugated diene polymer and aluminum sheet
The interfacial peel strength between a conjugated diene polymer and an aluminum sheet was measured by a 180-degree peel test using a multilayer body obtained by thermally welding a conjugated diene polymer to an aluminum sheet. Specifically, a 1 mm-thick aluminum sheet and a 2 mm-thick conjugated diene polymer sheet were stacked and fixed in a 2 mm-thick mold, preheated at 200°C for 5 minutes without applying pressure, then hot-pressed at 200°C for 2 minutes at 10 MPa, and then cold-pressed at 20°C for 3 minutes at 10 MPa to produce a multilayer body consisting of a 1 mm-thick aluminum sheet and a 1 mm-thick conjugated diene polymer. A 10 mm-wide slit was made in the surface of the resulting multilayer body facing the conjugated diene polymer, and the edge of the conjugated diene polymer layer was peeled off by several centimeters. The peeled portion of the conjugated diene polymer layer and the aluminum sheet were separately fixed to the chucks of a tensile tester [TGE-500N (product name), manufactured by MinebeaMitsumi Inc.]. The peeled portion of the layer made of conjugated diene polymer and the aluminum sheet were pulled in a direction of 180° at 300 mm/min to peel the two layers apart. The tensile force applied during peeling was taken as the interfacial peel strength (N/cm) of the multilayer body of the conjugated diene polymer and the aluminum sheet, and was evaluated according to the following criteria.
(Evaluation criteria)
○: 10 N/cm or more △: 3 N/cm or more and less than 10 N/cm ×: Less than 3 N/cm

(16) Adhesion strength per amount of modified group Calculated using the following formula.
Adhesion strength (N·cm ⁻¹ /g) per amount of modified group contained in 1 g of polymer=Interfacial peel strength (N·cm ⁻¹ )/(1 g×mass % of modified group/100)

(17) Binding property of conjugated diene polymer binder 0.15 g of a conjugated diene polymer, 0.35 g of acetylene black, and 4.5 g of toluene were stirred at 2000 rpm for 2 minutes with a stirrer, and an appropriate amount of toluene was added to adjust the viscosity to obtain a slurry. This slurry was applied to aluminum foil with an applicator, left to stand on a hot plate, dried at 50°C for 5 minutes, and further dried at 70°C for 10 hours to obtain an electrode in which the electrode layer and the current collector were integrated.

The electrode was wound around a SUS rod having a diameter of 10 mm, and the state of the curved electrode layer was visually observed to evaluate the binding property of the binder.
(Evaluation criteria)
○: No cracks in the electrode layer, showing strong adhesion. △: Cracks occurred in part of the electrode layer, showing moderate adhesion. ×: Cracks occurred throughout the electrode layer, showing weak adhesion.

(18) Smoothness of Coating Film The slurry for evaluating the binding property was applied to an aluminum foil, and the surface unevenness was visually confirmed and evaluated.
(Evaluation criteria)
○: No unevenness △: Unevenness in some areas ×: Unevenness throughout

(19) Volatility of Conjugated Diene Polymer Binder Solution 0.3 g of a conjugated diene polymer and 10 mL of toluene were placed in a 30 mL glass screw vial and shaken with a shaker to obtain a uniform solution. The vial containing the solution, with its lid removed, was left standing in a draft at an ambient temperature of 24°C, and the weight of the solvent that had evaporated after 10 hours was measured to evaluate the storage stability of the binder solution.
(Evaluation criteria)
◎: Less than 3 g, small change in composition when stored as a binder solution or slurry. ○: 3 g or more but less than 5 g, medium change in composition when stored as a binder solution or slurry. △: 5 g or more but less than 7 g, large change in composition when stored as a binder solution or slurry. ×: 7 g or more, large change in composition when stored as a binder solution or slurry.

(20) Dispersibility of Conductive Aid 0.2 g of a conjugated diene polymer, 0.4 g of acetylene black, and 19.4 g of toluene were placed in a 30 mL glass screw vial, and the vial was shaken for 1 hour using a shaker. Immediately after the shaker, the vial was visually observed in a stationary state to evaluate the dispersion state of the acetylene black.
(Evaluation criteria)
◯: Acetylene black is dispersed. △: Acetylene black is observed to have agglomerated, occupying less than 20% of the vial wall surface above the liquid surface. ×: Acetylene black is observed to have agglomerated, occupying 20% or more of the vial wall surface above the liquid surface.

(21) Storage Stability of Conjugated Diene Polymer Binder The conjugated diene polymer was stored in an environment of 23°C/50% humidity for 1 day, and the IR before and after storage was
(Evaluation criteria)
Present: There is a change in IR due to the functional group.
None: No change in IR due to functional groups.

(22) Electrochemical Stability of Electrode Layer Containing Conjugated Diene Polymer Binder 0.15 g of a conjugated diene polymer, 0.35 g of acetylene black, and 4.5 g of toluene were stirred with a stirrer at 2000 rpm for 2 minutes, and then an appropriate amount of toluene was added to adjust the viscosity, followed by stirring at 2000 rpm for 2 minutes to obtain a slurry. This slurry was applied to a platinum foil with an applicator, left to stand on a hot plate, dried at 50°C for 5 minutes, and then further dried at 70°C for 10 hours to obtain an electrode for evaluation on the oxidation side, in which the electrode layer and current collector were integrated.

0.5 g of conjugated diene polymer and 4.5 g of toluene were stirred at 2000 rpm for 2 minutes using a stirrer to obtain a slurry. This slurry was applied to platinum foil using an applicator, placed on a hot plate, and dried at 50°C for 5 minutes, and then further dried at 70°C for 10 hours to obtain a reduction-side evaluation electrode in which the electrode layer and current collector were integrated.

In a glove box under an argon atmosphere with a dew point controlled to −60° C. or below, a measurement laminate cell was prepared by connecting a platinum lead to an oxidation-side evaluation electrode or a reduction-side evaluation electrode (each 14 mm × 20 mm square) formed by integrating an electrode layer containing a conjugated diene polymer binder with a current collector, to form a working electrode; a nickel lead to a lithium metal sheet connected to a counter electrode; a nickel lead to a lithium metal sheet connected to a reference electrode; and a laminated sheet of microporous membrane separator and glass nonwoven fabric as a separator between the electrodes. These were then housed in an aluminum laminate sheet exterior, and 1 M LiPF ₆ /(ethylene carbonate/methyl ethyl carbonate (=30 wt %/70 wt %)) was poured into the exterior as an electrolyte, and the exterior was then sealed to prepare a measurement laminate cell. Measurements were performed using this cell under the following conditions.
(conditions)
Measurement method: Linear sweep voltammetry Sweep rate: 2 mV/sec
Voltage range: (oxidation side) 3.0 V (initial voltage) -5.4 V (final voltage) vs. Li/Li ⁺ /V
(Reducing side) 3.0 V (initial voltage) -0.0 V (final voltage) vs. Li/Li ⁺ /V
Electrode area: 2.8cm ² (14mm x 20mm)
Temperature: 25℃

The electrochemical stability of an electrode layer containing a conjugated diene polymer binder is evaluated as pass (good) if, on the oxidation side, the voltage at which the current value is 0.0005 A/mg or more at 3.0 V (vs. Li/Li ⁺ /V) or more is 4.6 V (vs. Li/Li ⁺ /V) or more, and, on the reduction side, the voltage at which the current value is −0.00005 A/mg or less at less than 3.0 V (vs. Li/Li ⁺ /V) is less than 0.1 V (vs. Li/Li ⁺ /V).

(23) Water Content of Conjugated Diene Polymer Using a Karl Fischer moisture meter, the moisture content is measured under the conditions of a sample weight of 1.50 g, a vaporizer temperature of 200°C, and a carrier gas (nitrogen) of 250 mL/min. If the moisture content is 200 ppm or less, the polymer is evaluated as pass (◯).

(Preparation of hydrogenation catalyst)
The hydrogenation catalyst used in the hydrogenation reaction of the conjugated diene polymer was prepared by the following method.
1 L of dried and purified cyclohexane was placed in a nitrogen-purged reaction vessel, and 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. An n-hexane solution containing 200 mmol of trimethylaluminum was then added with sufficient stirring, and the mixture was allowed to react at room temperature for approximately 3 days to obtain a hydrogenation catalyst.

[Production of Conjugated Diene Block Copolymer]
[Production Example 1]
(Production of conjugated diene block copolymer (a-1))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto so that the amount was 0.13 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 68 parts by mass of butadiene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 32% by mass, a polystyrene block content of 32% by mass, and a vinyl bond content of 36 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-1) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight average molecular weight of 69,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 2]
(Production of conjugated diene block copolymer (a-2))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto so that the amount was 0.12 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 9.5 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 81 parts by mass of butadiene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 9.5 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 19% by mass, a polystyrene block content of 19% by mass, and a vinyl bond content of 36 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-2) had a styrene content of 19% by mass, a butylene content of 36 mol%, a weight average molecular weight of 85,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 3]
(Production of conjugated diene block copolymer (a-3))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.08 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.5 mol of TMEDA (tetramethylethylenediamine) was added relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 6.5 parts by mass of styrene (based on 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 87 parts by mass of butadiene was added and polymerized at 50°C for 80 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 6.5 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added to obtain a conjugated diene block copolymer.

The resulting conjugated diene block copolymer had a styrene content of 13% by mass, a polystyrene block content of 13% by mass, and a vinyl bond content of 45 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-3) had a styrene content of 13% by mass, a butylene content of 45 mol%, a weight average molecular weight of 80,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 4]
(Production of conjugated diene-based block copolymer (a-4))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.11 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 1.5 mol of TMEDA (tetramethylethylenediamine) relative to 1 mol of n-butyllithium and 0.05 mol of sodium t-pentoxide relative to 1 mol of n-butyllithium were added thereto.

Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 5 parts by mass of butadiene (based on 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 9 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 77 parts by mass of butadiene was added, and polymerization was carried out at 50°C for 80 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 9 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. After the reaction was completed, methanol was added to obtain a conjugated diene block copolymer.

The resulting conjugated diene block copolymer had a styrene content of 18% by mass, a polystyrene block content of 18% by mass, and a vinyl bond content of 73 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.
After completion of the hydrogenation reaction, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer relative to 100 parts by mass of the conjugated diene block copolymer to produce an unmodified, hydrogenated conjugated diene block copolymer (a-4).

The obtained hydrogenated conjugated diene block copolymer (a-4) had a styrene content of 18% by mass, a butylene content of 73 mol%, a weight average molecular weight of 107,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 5]
(Production of conjugated diene block copolymer (a-5))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.07 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 1.8 mol of TMEDA (tetramethylethylenediamine) relative to 1 mol of n-butyllithium and 0.05 mol of sodium t-pentoxide relative to 1 mol of n-butyllithium were added thereto.

Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 5 parts by mass of butadiene (based on 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 7 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 82 parts by mass of butadiene was added, and polymerization was carried out at 50°C for 80 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 6 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. After the reaction was completed, methanol was added to obtain a conjugated diene block copolymer.

The resulting conjugated diene block copolymer had a styrene content of 13% by mass, a polystyrene block content of 13% by mass, and a vinyl bond content of 78 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene-based block copolymer so that the concentration in terms of titanium based on the block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce hydrogenated conjugated diene block copolymer (a-5).

The obtained hydrogenated conjugated diene block copolymer (a-5) had a styrene content of 13% by mass, a butylene content of 78 mol%, a weight average molecular weight of 160,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 6]
(Production of conjugated diene block copolymer (a-6))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.07 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 1.8 mol of TMEDA (tetramethylethylenediamine) relative to 1 mol of n-butyllithium and 0.05 mol of sodium t-pentoxide relative to 1 mol of n-butyllithium were added thereto.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 6.5 parts by mass of styrene (based on 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added, and polymerization was carried out at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 87 parts by mass of butadiene was added, and polymerization was carried out at 50°C for 80 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 6.5 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene-based block copolymer was obtained.

The resulting conjugated diene block copolymer had a styrene content of 13% by mass, a polystyrene block content of 13% by mass, and a vinyl bond content of 78 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene-based block copolymer so that the concentration in terms of titanium based on the block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce hydrogenated conjugated diene block copolymer (a-6).

The obtained hydrogenated conjugated diene block copolymer (a-6) had a styrene content of 13% by mass, a butylene content of 78 mol%, a weight average molecular weight of 160,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 7]
(Production of conjugated diene block copolymer (a-7))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.05 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.05 mol of TMEDA (tetramethylethylenediamine) was added relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 10 parts by mass of butadiene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added, and polymerization was carried out at 65°C for 20 minutes. Next, 1.50 mol of TMEDA per 1 mol of n-butyllithium and 0.05 mol of sodium t-pentoxide per 1 mol of n-butyllithium were added, followed by the addition of a cyclohexane solution (butadiene concentration: 20% by mass) containing 85 parts by mass of butadiene, and polymerization was carried out at 60°C for 70 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 5 parts by mass of styrene was added, and polymerization was carried out at 65°C for 15 minutes. After the reaction was completed, methanol was added to obtain a conjugated diene block copolymer.

The resulting conjugated diene block copolymer had a styrene content of 5% by mass, a polystyrene block content of 5% by mass, and a vinyl bond content of 78 mol% in the polymer block primarily composed of conjugated diene monomer units (hereinafter also referred to as the "butadiene portion").

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene-based block copolymer so that the concentration in terms of titanium based on the block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce hydrogenated conjugated diene block copolymer (a-7).

The obtained hydrogenated conjugated diene block copolymer (a-7) had a styrene content of 5% by mass, a butylene content of 78 mol%, a weight average molecular weight of 249,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 8]
(Production of conjugated diene block copolymer (a-8))
<Step 1>
Batch polymerization was carried out using a jacketed tank reactor equipped with a stirrer and an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.10 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 1.8 mol of TMEDA (tetramethylethylenediamine) relative to 1 mol of n-butyllithium and 0.05 mol of sodium t-pentoxide relative to 1 mol of n-butyllithium were added thereto.

Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 5 parts by mass of butadiene (based on 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added, and polymerization was carried out at 70°C for 20 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 21.5 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 52 parts by mass of butadiene was added, and polymerization was carried out at 50°C for 80 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 21.5 parts by mass of styrene was added, and polymerization was carried out at 70°C for 45 minutes. After the reaction was completed, methanol was added to obtain a conjugated diene block copolymer.

The resulting conjugated diene block copolymer had a styrene content of 43% by mass, a polystyrene block content of 43% by mass, and a vinyl bond content of 78 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained block copolymer so that the concentration in terms of titanium based on the block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce hydrogenated conjugated diene block copolymer (a-8).

The obtained hydrogenated conjugated diene block copolymer (a-8) had a styrene content of 43% by mass, a butylene content of 78 mol%, a weight average molecular weight of 103,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 9]
(Production of conjugated diene block copolymers (a-9-1 to a-9-13))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.04 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 68 parts by mass of butadiene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 32% by mass, a polystyrene block content of 32% by mass, and a vinyl bond content of 36 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-9-1) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight average molecular weight of 285,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

Tris(2,4-di-tert-butylphenoxy)phosphine was added to (a-9-1) to give concentrations of 10 ppm, 50 ppm, and 100 ppm in terms of phosphorus atoms to obtain (a-9-2), (a-9-3), and (a-9-4), respectively.

The resulting hydrogenated block copolymer solution was deashed as follows to reduce the amount of metals originating from the initiator and hydrogenation catalyst. Specifically, after the completion of the decalcification, 30 parts by weight of a water/sulfuric acid mixed solution was added to 100 parts by weight of the hydrogenated block copolymer. The amount of sulfuric acid added was adjusted so that the pH of the water removed in a decanter in a subsequent process would be 7.0. Most of the water was removed from the solution in a decanter until the water content was reduced to 3 parts by weight, and 0.4 mol of carbon dioxide gas was added per 1 mol of metal initiator and mixed. Then, 0.3 parts by weight of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer. The solution was subjected to the steam stripping method described in JP-B 05-54845 (a method in which most of the solvent is removed in water at 90 to 98°C, and then the aqueous dispersion slurry having a crumb concentration of about 5% by weight is introduced into a twin-screw extruder to remove the solvent), thereby obtaining hydrogenated block copolymers (a-9-5) and (a-9-6).

The obtained hydrogenated conjugated diene block copolymer (a-9-1) was freeze-pulverized to obtain (a-9-7) to (a-9-11), each with a loose bulk density and dispersity shown in the table.

The obtained hydrogenated conjugated diene block copolymer (a-9-1) was freeze-pulverized to obtain (a-9-12) and (a-9-13), respectively, in which amorphous silica and calcium stearate were added to the conjugated diene block copolymer with the loose bulk density and dispersity values shown in the table.

[Production Example 10]
(Production of amine-conjugated diene polymer)
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto so that the amount was 0.13 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 68 parts by mass of butadiene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. Next, 1,3-dimethyl-2-imidazolidinone (hereinafter also abbreviated as "DMI") was added in an amount equal to 1 mole per mole of n-butyllithium, and the mixture was allowed to react at 70°C for 10 minutes. After the reaction was completed, methanol was added, and a modified conjugated diene-based block copolymer was obtained (Step 1). The resulting conjugated diene-based block copolymer had a styrene content of 32% by mass, a polystyrene block content of 32% by mass, and a vinyl bond content of 36 mol% in the butadiene moiety.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained modified conjugated diene block copolymer so that the concentration in terms of titanium relative to the modified conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the modified conjugated diene block copolymer to produce a hydrogenated modified conjugated diene block copolymer.

The resulting hydrogenated conjugated diene block copolymer (a-10) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 75,000, a molecular weight distribution of 1.2, a hydrogenation rate of 72 mol%, and a modification rate of 65% (the number of modifying groups per polymer chain was 0.65).

[Production of modified conjugated diene block copolymer]
A conjugated diene polymer was produced using the following materials.
Maleic anhydride (Fuso Chemical Co., Ltd.)
Radical initiator: Perhexa 25B (manufactured by NOF Corporation)

[Production Example 11]
(Production of Modified Conjugated Diene Block Copolymer (aa-1))
<Step 3>
100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-1), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B were dry blended and melt-kneaded in a twin-screw extruder TEX30 (manufactured by The Japan Steel Works, Ltd.) at a cylinder setting temperature of 210°C, a screw rotation speed of 253 rpm, and a discharge rate of 5 kg/hour to produce a maleic anhydride conjugated diene polymer (aa-1).

[Production Example 12]
(Production of modified conjugated diene-based block copolymer (aa-2a))
<Step 3>
A conjugated diene polymer (aa-2a) was produced in the same manner as in Production Example 11, except that 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-2), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B were dry blended.

[Production Example 13]
(Production of modified conjugated diene-based block copolymer (aa-2b))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-2b) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-2), 4.2 parts by mass of maleic anhydride, and 0.48 parts by mass of Perhexa 25B.

[Production Example 14]
(Production of modified conjugated diene-based block copolymer (aa-3))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-3) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-3), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B.

[Production Example 15]
(Production of modified conjugated diene-based block copolymer (aa-4))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-4) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-4), 1.4 parts by mass of maleic anhydride, and 0.08 parts by mass of Perhexa 25B.

[Production Example 16]
(Production of modified conjugated diene-based block copolymer (aa-5))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-5) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-5), 1.4 parts by mass of maleic anhydride, and 0.08 parts by mass of Perhexa 25B.

[Production Example 17]
(Production of modified conjugated diene-based block copolymer (aa-6))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-6) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-6), 1.4 parts by mass of maleic anhydride, and 0.08 parts by mass of Perhexa 25B.

[Production Example 18]
(Production of modified conjugated diene-based block copolymer (aa-7))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-7) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-7), 1.4 parts by mass of maleic anhydride, and 0.08 parts by mass of Perhexa 25B.

[Production Example 19]
(Production of modified conjugated diene-based block copolymer (aa-8))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-8) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-8), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B.

[Production Example 20]
(Production of modified conjugated diene-based block copolymer (aa-9))
<Step 3>
A maleic anhydride conjugated diene polymer (aa-9) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-9), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B, and the cylinder set temperature was changed to 240°C.

[Production Example 21]
(Production of conjugated diene block copolymer (a-11))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.04 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 68 parts by mass of butadiene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 16 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 32% by mass, a polystyrene block content of 32% by mass, and a vinyl bond content of 36 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-11) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight average molecular weight of 287,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 75 mol%.

[Production Examples 22 to 25]
(Production of conjugated diene block copolymers (a-12 to 15))
The production was carried out in the same manner as in Production Example 9, except for adjusting the amounts of n-butyllithium and TMEDA.

The resulting hydrogenated conjugated diene block copolymer (a-12) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 190,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%. (a-13-1) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 351,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%. (a-14) had a styrene content of 32% by mass, a butylene content of 58 mol%, a weight-average molecular weight of 351,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%. (a-15-1) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 451,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

Tris(2,4-di-tert-butylphenoxy)phosphine was added to (a-13-1) to give concentrations of 10 ppm, 50 ppm, and 100 ppm in terms of phosphorus atoms, to obtain (a-13-2), (a-13-3), and (a-13-4), respectively.

The resulting hydrogenated block copolymer solution was deashed as follows to reduce the amount of metals originating from the initiator and hydrogenation catalyst. Specifically, after the completion of the decalcification, 30 parts by weight of a water/sulfuric acid mixed solution was added to 100 parts by weight of the hydrogenated block copolymer. The amount of sulfuric acid added was adjusted so that the pH of the water removed in a decanter in a subsequent process would be 7.0. Most of the water was removed from the solution in a decanter until the water content was reduced to 3 parts by weight, and 0.4 mol of carbon dioxide gas was added per 1 mol of metal initiator and mixed. Then, 0.3 parts by weight of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer. The solution was subjected to the steam stripping method described in JP-B 05-54845 (a method in which most of the solvent is removed in water at 90 to 98°C, and then the aqueous dispersion slurry having a crumb concentration of about 5% by weight is introduced into a twin-screw extruder to remove the solvent), thereby obtaining hydrogenated block copolymers (a-13-5) and (a-13-6).

The obtained hydrogenated conjugated diene block copolymer (a-13-1) was freeze-pulverized to obtain (a-13-7) to (a-13-11), each with a loose bulk density and dispersity shown in the table.

The obtained hydrogenated conjugated diene block copolymer (a-13-1) was freeze-pulverized to obtain (a-13-12) and (a-13-13), respectively, in which amorphous silica and calcium stearate were added to the conjugated diene block copolymer with the loose bulk density and dispersity values shown in the table.

Tris(2,4-di-tert-butylphenoxy)phosphine was added to (a-15-1) to give concentrations of 10 ppm, 50 ppm, and 100 ppm in terms of phosphorus atoms to obtain (a-15-2), (a-15-3), and (a-15-4), respectively.

The resulting hydrogenated block copolymer solution was deashed as follows to reduce the amount of metals originating from the initiator and hydrogenation catalyst. Specifically, after the completion of the decalcification, 30 parts by weight of a water/sulfuric acid mixed solution was added to 100 parts by weight of the hydrogenated block copolymer. The amount of sulfuric acid added was adjusted so that the pH of the water removed in a decanter in a subsequent process would be 7.0. Most of the water was removed from the solution in a decanter until the water content was reduced to 3 parts by weight, and 0.4 mol of carbon dioxide gas was added per 1 mol of metal initiator and mixed. Then, 0.3 parts by weight of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer. The solution was subjected to the steam stripping method described in JP-B 05-54845 (a method in which most of the solvent is removed in water at 90 to 98°C, and then the aqueous dispersion slurry having a crumb concentration of about 5% by weight is introduced into a twin-screw extruder to remove the solvent), thereby obtaining hydrogenated block copolymers (a-15-5) and (a-15-6).

The obtained hydrogenated conjugated diene block copolymer (a-15-1) was freeze-pulverized to obtain (a-15-7) to (a-15-11), each with a loose bulk density and dispersity shown in the table.

The obtained hydrogenated conjugated diene block copolymer (a-15-1) was freeze-pulverized to obtain (a-15-12) and (a-15-13), respectively, in which amorphous silica and calcium stearate were added to the conjugated diene block copolymer with the loose bulk density and dispersity values shown in the table.

[Production Example 26]
(Production of conjugated diene block copolymer (a-16))
Production was carried out in the same manner as in Production Example 9, except that the amount of n-butyllithium was changed and styrene was introduced in amounts of 9.5 parts by mass each.

The obtained hydrogenated conjugated diene block copolymer (a-16) had a styrene content of 19% by mass, a butylene content of 36 mol%, a weight average molecular weight of 352,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 27]
(Production of conjugated diene block copolymer (a-17))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto in an amount of 0.04 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 0.3 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 15 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 70°C for 45 minutes. Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 35 parts by mass of butadiene and 35 parts by mass of isoprene was added and polymerized at 70°C for 1.5 hours. Finally, a cyclohexane solution (styrene concentration: 20% by mass) containing 15 parts by mass of styrene was added and polymerized at 70°C for 45 minutes. After the reaction was completed, methanol was added, and a conjugated diene block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 30% by mass, a polystyrene block content of 30% by mass, and a vinyl bond content of 36 mol% in the butadiene/isoprene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration relative to the conjugated diene block copolymer was 100 ppm, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-17) had a styrene content of 30% by mass, a butylene content of 36 mol%, a weight average molecular weight of 450,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

[Production Example 28]
(Production of conjugated diene block copolymer (a-18))
<Step 1>
Batch polymerization was carried out using a tank-type reactor equipped with a stirrer and a jacket and having an internal volume of 10 L. 1 L of cyclohexane was placed in the reactor, and n-butyllithium was added thereto so that the amount was 0.056 parts by mass relative to 100 parts by mass of the total monomers. Furthermore, 1.2 mol of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added thereto relative to 1 mol of n-butyllithium.

Next, a cyclohexane solution (styrene concentration: 20% by mass) containing 20 parts by mass of styrene (relative to 100 parts by mass of total monomers; the same applies hereinafter in this paragraph) was added to the reactor and polymerized at 45°C for 30 minutes. Next, a cyclohexane solution (butadiene concentration: 20% by mass) containing 80 parts by mass of butadiene was added and polymerized at 80°C for 1.0 hour. Finally, 0.27 mol of tetramethoxysilane was added per 1 mol of n-butyllithium to carry out a coupling reaction. After the reaction was completed, methanol was added, and a conjugated diene-based block copolymer was obtained as step 1.

The resulting conjugated diene block copolymer had a styrene content of 20% by mass, a polystyrene block content of 20% by mass, and a vinyl bond content of 63 mol% in the butadiene portion.

<Step 2>
The above-mentioned hydrogenation catalyst was added to the obtained conjugated diene block copolymer so that the titanium-equivalent concentration was 100 ppm per 100 parts by mass of the conjugated diene block copolymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.7 MPa and a temperature of 70°C.

After the hydrogenation reaction was completed, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer per 100 parts by mass of the conjugated diene block copolymer to produce a hydrogenated conjugated diene block copolymer.

The obtained hydrogenated conjugated diene block copolymer (a-18) had a styrene content of 20% by mass, a butylene content of 62 mol%, a weight average molecular weight of 434,000, a molecular weight distribution of 2.3, and a hydrogenation rate of 99 mol%.

[Production Examples 29 to 35]
(Production of amine-conjugated diene polymers (a-19 to 25))
The production was carried out in the same manner as in Production Example 10, except that the amounts of n-butyllithium, TMEDA, and DMI were changed.

The obtained hydrogenated conjugated diene block copolymer (a-19) had a styrene content of 32% by mass, a butylene content of 30 mol%, a weight-average molecular weight of 180,000, a molecular weight distribution of 1.1, a hydrogenation rate of 87 mol%, and a modification rate of 71% (the number of modifying groups per polymer chain was 0.71).

The resulting hydrogenated conjugated diene block copolymer (a-20) had a styrene content of 32% by mass, a butylene content of 21 mol%, a weight-average molecular weight of 203,000, a molecular weight distribution of 1.1, a hydrogenation rate of 87 mol%, and a modification rate of 71% (0.71 modified groups per polymer chain). The resulting hydrogenated conjugated diene block copolymer (a-21) had a styrene content of 32% by mass, a butylene content of 30 mol%, a weight-average molecular weight of 203,000, a molecular weight distribution of 1.1, a hydrogenation rate of 87 mol%, and a modification rate of 70% (0.70 modified groups per polymer chain). (a-22) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 252,000, a molecular weight distribution of 1.1, a hydrogenation rate of 84 mol%, and a modification rate of 71% (0.71 modified groups per polymer chain). (a-23) had a styrene content of 32 mass%, a butylene content of 36 mol%, a weight-average molecular weight of 251,000, a molecular weight distribution of 1.1, a hydrogenation rate of 84 mol%, and a modification rate of 25% (the number of modifying groups per polymer chain was 0.25). (a-24) had a styrene content of 32 mass%, a butylene content of 36 mol%, a weight-average molecular weight of 351,000, a molecular weight distribution of 1.1, a hydrogenation rate of 84 mol%, and a modification rate of 71% (the number of modifying groups per polymer chain was 0.71). (a-25) had a styrene content of 32 mass%, a butylene content of 36 mol%, a weight-average molecular weight of 450,000, a molecular weight distribution of 1.1, a hydrogenation rate of 84 mol%, and a modification rate of 71% (the number of modifying groups per polymer chain was 0.71).

[Production Example 36]
(Production of amine-conjugated diene polymer (a-26))
Production was carried out in the same manner as in Production Example 10, except that the amount of n-butyllithium was changed and styrene was introduced in an amount of 19.0 parts by mass each.

The obtained hydrogenated conjugated diene block copolymer (a-26) had a styrene content of 38% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 252,000, a molecular weight distribution of 1.1, a hydrogenation rate of 83 mol%, and a modification rate of 70% (the number of modifying groups per polymer chain was 0.70).

[Production Example 37]
(Production of amine-conjugated diene polymer (a-27))
Production was carried out in the same manner as in Production Example 10, except that the amount of n-butyllithium was changed and styrene was introduced in an amount of 21 parts by mass each.

The resulting hydrogenated conjugated diene block copolymer (a-27) had a styrene content of 42% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 252,000, a molecular weight distribution of 1.1, a hydrogenation rate of 84 mol%, and a modification rate of 75% (the number of modifying groups per polymer chain was 0.75).

[Production Example 38]
(Production of amine-conjugated diene polymer (a-28))
Production was carried out in the same manner as in Production Example 10, except that the amount of n-butyllithium was changed and styrene was introduced in amounts of 6.5 parts by mass each.

The resulting hydrogenated conjugated diene block copolymer (a-28) had a styrene content of 13% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 250,000, a molecular weight distribution of 1.1, a hydrogenation rate of 83 mol%, and a modification rate of 75% (the number of modifying groups per polymer chain was 0.75).

[Production Example 39]
(Production of amine-conjugated diene polymer (a-29))
The production was carried out in the same manner as in Production Example 10, except that the amounts of n-butyllithium and TMEDA were adjusted.

The resulting hydrogenated conjugated diene block copolymer (a-29) had a styrene content of 32% by mass, a butylene content of 59 mol%, a weight-average molecular weight of 250,000, a molecular weight distribution of 1.1, a hydrogenation rate of 83 mol%, and a modification rate of 75% (the number of modifying groups per polymer chain was 0.75).

[Manufacture Example 40]
(Production of amine-conjugated diene polymer (a-30))
A hydrogenated product was produced in the same manner as in (a-24), except that N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane was used instead of DMI, and then a modified conjugated diene-based block copolymer (a-30) was produced by removing the silyl protecting groups.

The obtained hydrogenated conjugated diene block copolymer (a-30) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 351,000, a molecular weight distribution of 1.1, a hydrogenation rate of 90 mol%, and a modification rate of 90% (the number of modifying groups per polymer chain was 0.9).

[Manufacture Example 41]
(Production of amine-conjugated diene polymer (a-31))
A hydrogenated product was produced in the same manner as in (a-24) except that 1-(4-dimethylaminophenyl)-1-phenylethylene was used instead of DMI, to produce a modified conjugated diene block copolymer (a-31).

The obtained hydrogenated conjugated diene block copolymer (a-31) had a styrene content of 32% by mass, a butylene content of 36 mol%, a weight average molecular weight of 351,000, a molecular weight distribution of 1.1, a hydrogenation rate of 90 mol%, and a modification rate of 90% (the number of modifying groups per polymer chain was 0.9).

[Manufacture Example 42]
(Production of amine-conjugated diene polymer (a-32))
The same procedures as in Production Example 10 were repeated except that the amount of n-butyllithium, the amount of TMEDA, and the amount of styrene were changed so that each was 6.5 parts by mass.

The resulting hydrogenated conjugated diene block copolymer (a-32) had a styrene content of 13% by mass, a butylene content of 36 mol%, a weight-average molecular weight of 151,000, a molecular weight distribution of 1.2, a hydrogenation rate of 87 mol%, and a modification rate of 80% (the number of modifying groups per polymer chain was 0.80).

[Manufacture Example 43]
(Production of amine-conjugated diene polymer (a-33))
This was produced in the same manner as in Production Example 10, except for changing the amount of n-butyllithium.

The resulting hydrogenated conjugated diene block copolymer (a-33) had a styrene content of 32% by mass, a butylene content of 38 mol%, a weight-average molecular weight of 60,000, a molecular weight distribution of 1.2, a hydrogenation rate of 87 mol%, and a modification rate of 72% (the number of modifying groups per polymer chain was 0.72).

[Manufacture Example 44]
(Production of amine-conjugated diene polymer (a-34))
Production was carried out in the same manner as in Production Example 10, except that the amount of n-butyllithium was changed, and the amount of TMEDA and styrene were changed so that 12.5 parts by mass were introduced.

The resulting hydrogenated conjugated diene block copolymer (a-34) had a styrene content of 25% by mass, a butylene content of 54 mol%, a weight-average molecular weight of 90,000, a molecular weight distribution of 1.2, a hydrogenation rate of 98 mol%, and a modification rate of 90% (the number of modifying groups per polymer chain was 0.9).

[Manufacture Example 45]
(Production of modified conjugated diene-based block copolymer (aa-10))
A maleic anhydride conjugated diene polymer (aa-10) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-13), 1.5 parts by mass of maleic anhydride, and 0.10 parts by mass of Perhexa 25B, and the cylinder set temperature was changed to 240°C.

[Manufacture Example 46]
(Production of modified conjugated diene block copolymer (aa-11))
A maleic anhydride conjugated diene polymer (aa-11) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-13), 2.1 parts by mass of maleic anhydride, and 0.14 parts by mass of Perhexa 25B, and the cylinder set temperature was changed to 240°C.

[Manufacture example 47]
(Production of modified conjugated diene-based block copolymer (aa-12))
A maleic anhydride conjugated diene polymer (aa-12) was produced in the same manner as in Production Example 11, except that the components used in dry blending were changed to 100 parts by mass of the pelletized hydrogenated conjugated diene polymer (a-13), 2.1 parts by mass of maleic anhydride, and 0.12 parts by mass of Perhexa 25B, and the cylinder set temperature was changed to 250°C.

[Manufacture example 48]
(Production of conjugated diene polymer (a-35))
Except for changing the amount of n-butyllithium, production was carried out in the same manner as in Production Example 1. The obtained hydrogenated conjugated diene block copolymer (a-35) had a styrene content of 32 mass%, a butylene content of 36 mol%, a weight average molecular weight of 39,000, a molecular weight distribution of 1.2, and a hydrogenation rate of 99 mol%.

(Polyvinylidene fluoride (a-36))
PVDF (polyvinylidene fluoride, manufactured by Kureha Corporation, KF-1100) was used as the binder (a-36).

For Examples 1 to 85 and Comparative Examples 1 and 2, electrodes were prepared and evaluated according to the above-mentioned formulation.

The results in Table 1 indicate that Examples 1 to 85 are conjugated diene polymers with excellent adhesion and electrochemical stability, as well as low moisture content, making them suitable as binders for all-solid-state batteries. Among these, high-molecular-weight binders with modified groups exhibited an excellent balance of adhesion, binding, and volatility. Even high-molecular-weight binders with low modified group equivalents, such as those in Examples 65 to 80, exhibited high binding properties. Furthermore, binders with fewer modified groups were found to have excellent dispersibility of conductive additives even when polymerized. Furthermore, Examples 21-23, 36-38, and 50-52 indicated that binders containing phosphorus compounds exhibited excellent thermal stability. Furthermore, Examples 24-25, 39-40, and 53-54 indicated that binders with low metal residues exhibited excellent thermal stability. Thermal stability is an indicator of thermal degradation during pre-drying before use and a decline in battery performance. Furthermore, Examples 26-30, 41-45, and 55-59 show that binders with low compressibility have excellent feed stability, and Examples 31-32, 46-47, and 60-61 show that binders to which an external lubricant is applied have excellent feed stability.

The modified conjugated diene block copolymer of the present invention has industrial applicability as a binder for batteries, including all-solid-state batteries.

100 All solid battery 110 Solid electrolyte layer 140 Positive electrode layer 150 Negative electrode layer 160 Positive electrode current collector 170 Negative electrode current collector 180 Exterior

Claims (23)

The polymer block has a polymer block mainly composed of a vinyl aromatic monomer unit, and has a weight average molecular weight of 40,000 to 2,000,000.
Contains a conjugated diene polymer,
the conjugated diene polymer has a modifying group, and the modifying group is at least one selected from the group consisting of an acid anhydride group, a hydroxyl group, a carbonyl group, a carboxyl group , an amino group, an epoxy group, an amide group, a urethane group, a urea group, an isocyanate group, and an ionic group;
the modifying group is present in an amount of 0.10 mmol or more and 0.50 mmol or less in 100 g of the conjugated diene polymer;
Solid-state battery binder. The all-solid-state battery binder according to claim 1, wherein the weight-average molecular weight of the conjugated diene polymer is 200,000 to 800,000. the content of the polymer block is 40% by weight or less based on the total amount of the conjugated diene-based polymer;
The all-solid-state battery binder according to claim 1 or 2. the amount of vinyl bonds in the conjugated diene monomer units contained in the conjugated diene polymer before hydrogenation is 20 mol % to 60 mol % relative to 100 mol % in total of the conjugated diene monomer units;
The all-solid-state battery binder according to any one of claims 1 to 3. the conjugated diene polymer has a toluene-insoluble content of 10 wt % or less;
The all-solid-state battery binder according to any one of claims 1 to 4. the modifying group is a primary amino group or a secondary amino group;
The all-solid-state battery binder according to any one of claims 1 to 5. an end or a coupling portion of the conjugated diene polymer has the modifying group;
The all-solid-state battery binder according to any one of claims 1 to 6. the conjugated diene polymer has a polymer block mainly composed of a conjugated diene monomer unit;
The all-solid-state battery binder according to any one of claims 1 to 7. The conjugated diene polymer is hydrogenated.
The all-solid-state battery binder according to any one of claims 1 to 8. the butylene amount and/or propylene amount of the conjugated diene monomer units contained in the conjugated diene polymer is 20 mol % to 60 mol % relative to 100 mol % in total of the conjugated diene monomer units;
the conjugated diene polymer has a polymer block mainly composed of a conjugated diene monomer unit;
The all-solid-state battery binder according to any one of claims 1 to 9. The conjugated diene polymer has a loose bulk density of 0.15 g/cm ^or more, a degree of compression of less than 30, and is in the form of powder or crumb.
The all-solid-state battery binder according to any one of claims 1 to 10. the total content of the transition metal element and Al, Li, Fe, Zn, and Mg in the conjugated diene polymer is 200 ppm or less in terms of atoms relative to the conjugated diene polymer;
The all-solid-state battery binder according to any one of claims 1 to 11. The composition contains the conjugated diene polymer and a phosphorus compound, and the phosphorus atom content is 10 ppm or more relative to the conjugated diene polymer.
The all-solid-state battery binder according to any one of claims 1 to 11. containing at least one selected from the group consisting of silica, higher fatty acid metal salts, polyolefins, and fatty acid amides;
The all-solid-state battery binder according to any one of claims 1 to 13. The conjugated diene polymer has isoprene as a conjugated diene polymer unit.
The all-solid-state battery binder according to any one of claims 1 to 14. The moisture content is 200 ppm or less.
The all-solid-state battery binder according to any one of claims 1 to 15. A slurry containing the all-solid-state battery binder described in any one of claims 1 to 16, having a water content of 200 ppm or less. The all-solid-state battery binder according to any one of claims 1 to 16,
a positive electrode active material,
A positive electrode layer having a moisture content of 200 ppm or less. The all-solid-state battery binder according to any one of claims 1 to 16,
an ion-conducting solid electrolyte;
A solid electrolyte layer having a moisture content of 200 ppm or less. The all-solid-state battery binder according to any one of claims 1 to 16,
a negative electrode active material,
A negative electrode layer having a moisture content of 200 ppm or less. The cathode layer according to claim 18, the solid electrolyte layer according to claim 19, and the anode layer according to claim 20 are included.
All-solid-state battery. The moisture content is 200 ppm or less.
The all-solid-state battery according to claim 21. a step of preparing a slurry containing a conjugated diene polymer having a conjugated diene monomer unit, a polymer block mainly composed of a vinyl aromatic monomer unit, and a modifying group, the conjugated diene polymer having a water content of 1 wt % or less, and a solvent;
and applying the slurry to a substrate and drying the slurry.
A method for producing at least one layer of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, the method comprising the all-solid-state battery binder according to claim 1, wherein the all -solid-state battery binder has a moisture content of 200 ppm or less.