JP7674112B2 - Complex - Google Patents

Description

The present invention relates to a composite having a composition layer containing a propylene-based polymer and a metal layer.

Traditionally, polypropylene has been widely used as a thermoplastic molding material with excellent rigidity, heat resistance, and transparency. Since polypropylene is a non-polar material, it has poor adhesion to metal materials such as aluminum. To improve adhesion, a technique for modifying polypropylene with unsaturated carboxylic acids or their derivatives is widely known.

In addition, polypropylene has poor flexibility, so when it is used as an adhesive resin, a soft rubber component is usually blended into the polypropylene. A polypropylene-based adhesive resin with improved adhesiveness has been proposed by blending a soft rubber component into the polypropylene (Patent Document 1).

On the other hand, metal cans have traditionally been used for secondary batteries, such as lithium-ion batteries. In recent years, in response to the demand for thinner and more diverse products, laminate packaging materials have come to be used, in which a composite of aluminum foil and a resin film laminated thereon is formed into a bag shape. Metal lead substrates made of aluminum, nickel, or the like are attached to the metal substrates of the positive and negative electrodes of lithium-ion batteries to extract electricity. In order to prevent short circuits between the lead substrate and the aluminum foil of the laminate packaging material and leakage of electrolyte, it has become common to sandwich and seal the sealing portion of the lead substrate with a film-shaped insulator (tab lead film) in order to improve the sealing strength between the lead substrate and the innermost resin layer (sealant) of the laminate packaging material (Patent Document 2 and Patent Document 3).

Also disclosed is a film for battery components that includes a fibrous or porous sheet containing a 4-methyl-1-pentene polymer and a layer made of modified polyolefin, and describes that it is possible to obtain a film for battery components such as a tab lead film that can be manufactured without a crosslinking process while maintaining heat resistance, flexibility, adhesive strength to electrodes, and interlayer adhesive strength equal to or greater than conventional products (Patent Document 4).

Japanese Patent Application Publication No. 04-300933 Japanese Unexamined Patent Publication No. 56-071278 JP 2001-102016 A JP 2016-026380 A

Tab lead films need to have high insulation properties, and also excellent peel strength against the lead substrate. For example, in recent years, there has been active research into turning lithium ion batteries into large, high-capacity batteries for use in automobiles, etc., and there is a demand for improved heat resistance and peel strength.

Although polymethylpentene resin has high heat resistance, it is necessary to use an adhesive to bond it to the lead substrate and polypropylene-based resin. Furthermore, when using polypropylene-based adhesive resin for bonding, there is a problem that polymethylpentene resin, which is non-polar and has low wettability, has low peel strength and is prone to peeling during co-extrusion molding, so it is necessary to make it into a fibrous or porous sheet before extrusion-coating the polypropylene-based adhesive resin.

The present invention was made in consideration of the above problems, and aims to provide a composite material obtained by co-extrusion molding that has excellent peel strength between a polymethylpentene resin and a polypropylene-based adhesive resin layer and a metal layer.

[1] A composition layer (I) formed from a composition (Ia);
A composite having a metal layer (II) in contact with the composition layer (I),
The composition (Ia) comprises
the content ratio of the propylene-based polymer (A) containing 75 to 100 mol % of structural units derived from propylene is 45 to 75 parts by mass,
The content of the ethylene polymer (B) is 0 to 20 parts by mass,
A composite comprising a copolymer having 60 mol % or more and 99 mol % or less of structural units derived from 4-methyl-1-pentene and 1 mol % or more and 40 mol % or less of structural units derived from an α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms, wherein the structural units derived from 4-methyl-1-pentene and the structural units derived from an α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms are 100 mol % in total, and the content of a thermoplastic resin (C) having a melting point Tm of 199° C. or less or substantially no melting point Tm measured by a differential scanning calorimeter (DSC) is 15 to 45 parts by mass (wherein the total of the components (A), (B) and (C) is taken as 100 parts by mass).
[2] The composite according to [1], wherein a part or all of the copolymers contained in the propylene-based polymer (A), the ethylene-based polymer (B), and the thermoplastic resin (C) are graft-modified with an unsaturated carboxylic acid and/or a derivative thereof.
[3] The composite according to [1] or [2], further comprising a polyolefin resin layer (III) formed on a surface of the composition layer (I) that is not in contact with the metal layer (II).
[4] The composite according to [3], further comprising the composition layer (I) formed on a surface of the polyolefin resin layer (III) that is not in contact with the metal layer (II).
[5] The composite according to any one of [1] to [4], wherein the polyolefin resin layer (III) contains a polymer in which the content ratio of structural units derived from 4-methyl-1-pentene to all structural units is 90 mol% or more and 100 mol% or less, and the content ratio of structural units derived from α-olefins other than 4-methyl-1-pentene to all structural units is 0 mol% or more and 10 mol% or less, and the melting point Tm measured by differential scanning calorimetry (DSC) is 200°C or more.
[6] The composition (Ia) further contains a carbodiimide-modified polyolefin (D), and in the composition (Ia), the content of component (A) is 45 to 65 parts by mass, the content of component (B) is 0 to 20 parts by mass, the content of component (C) is 15 to 45 parts by mass, and the content of component (D) is 5 to 30 parts by mass, per 100 parts by mass of the total of the components (A), (B), (C), and (D). The composite according to any one of [1] to [5].
[7] A tab lead for a lithium ion battery, comprising the composite according to any one of [1] to [6].
[8] A lithium ion battery having the tab lead according to [7].

According to the present invention, it is possible to provide a polyolefin resin composition layer having excellent adhesion between polymethylpentene resin and polyolefin resin such as polypropylene resin by coextrusion molding, and further, excellent peel strength with a metal layer, and a composite of these.

FIG. 1 is a diagram showing one embodiment of the composite of the present invention.

The following describes the embodiment of the present invention. In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

[Complex]
The complex of the present invention is
A composition layer (I) formed from a composition (Ia);
and a metal layer (II) in contact with the composition layer (I).

<Composition layer (I)>
The composition layer (I) is formed from a composition (Ia). The composition (Ia) contains a propylene-based copolymer (A) and a thermoplastic resin (C), and may further contain an ethylene-based polymer (B). The composition (Ia) may further contain a carbodiimide-modified polyolefin (D).

Hereinafter, the propylene-based copolymer (A), ethylene-based polymer (B), thermoplastic resin (C), and carbodiimide-modified polyolefin (D) will also be referred to as component (A), component (B), component (C), and component (D), respectively.

The composition layer (I) has high insulating properties and is excellent in peel strength with respect to the metal layer (II).
For this reason, the composition layer (I) is preferable as a tab lead film for metal lead substrates of positive and negative electrodes in a laminate packaging material for a lithium ion battery, for example.

Propylene-based polymer (A)
The propylene polymer (A) may be either isotactic polypropylene or syndiotactic polypropylene. The propylene polymer (A) may be either a homopolypropylene, or a random copolymer or a block copolymer of propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene). Specific examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, and 4-methyl-1-pentene, and may be a combination of two or more of these.

Particularly, from the viewpoint of heat resistance, ethylene and 1-butene are preferred.
The propylene polymer (A) contains 75 to 100 mol %, preferably 85 to 100 mol %, and more preferably 90 to 100 mol %, of structural units derived from propylene.

As the propylene-based polymer (A), the above polymers may be used alone or in combination.
The propylene polymer (A) has a density in the range of preferably 0.860 to 0.910 g/cm ³ , more preferably 0.875 to 0.910 g/cm ³ , and even more preferably 0.885 to 0.910 g/cm ^3. When the density is in the above range, the polymer has excellent heat resistance.

The propylene polymer (A) preferably has a melt flow rate (MFR) of 0.1 to 100 g/10 min, more preferably 0.2 to 50 g/10 min, and even more preferably 0.3 to 30 g/10 min, measured according to ASTM D 1238 at a temperature of 230°C under a load of 2.16 kg. When the MFR is in the above range, the polymer has excellent moldability and sealability.

Ethylene-based polymer (B)
The ethylene polymer (B) is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin. The α-olefin may be an α-olefin having 3 or more carbon atoms, preferably 3 to 10 carbon atoms, and specifically may be propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, or a combination of two or more of these. The copolymerization amount of the α-olefin is usually 25 mol% or less. When it is within the above range, it is excellent in terms of flexibility.

The ethylene polymer (B) has a density in the range of preferably 0.855 to 0.970 g/cm ³ , more preferably 0.860 to 0.940 g/cm ³ , and even more preferably 0.865 to 0.930 g/cm ^3. When the density is in the above range, the flexibility is excellent.

The ethylene polymer (B) preferably has a melt flow rate (MFR) of 0.1 to 20 g/10 min, more preferably 0.3 to 16 g/10 min, and even more preferably 0.5 to 10 g/10 min, measured according to ASTM D 1238 at a temperature of 190°C under a load of 2.16 kg. When the MFR is within the above range, the polymer has excellent moldability and sealability.

Thermoplastic resin (C)
The thermoplastic resin (C) contains a copolymer having structural units derived from 4-methyl-1-pentene and structural units derived from an α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms, in which the structural units derived from 4-methyl-1-pentene and the structural units derived from the α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms account for 100 mol % in total.

Examples of the α-olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene, and 1-octadecene. The α-olefins are preferably ethylene, propylene, 1-butene, 1-hexene, 1-octene, and 1-decene, more preferably ethylene, propylene, 1-butene, 1-hexene, and 1-octene, and even more preferably ethylene, propylene, 1-butene, and 1-hexene. The α-olefins may be used alone or in combination of two or more of these.

In the copolymer, the content of the structural units derived from 4-methyl-1-pentene is 60 mol% or more and 99 mol% or less, preferably 63 mol% or more and 98 mol% or less, more preferably 65 mol% or more and 95 mol% or less, even more preferably 65 mol% or more and 90 mol% or less, and particularly preferably 65 mol% or more and 87 mol% or less. The content of the structural units derived from α-olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene is 1 mol% or more and 40 mol% or less, preferably 2 mol% or more and 37 mol% or less, more preferably 5 mol% or more and 35 mol% or less, even more preferably 10 mol% or more and 35 mol% or less, and particularly preferably 13 mol% or more and 35 mol% or less. When the amount of the structural units is within the above range, the resulting composition has excellent heat resistance and adhesive strength.

The copolymer preferably has a melt flow rate (MFR) of 0.5 to 50/10 min, more preferably 0.5 to 30 g/10 min, at 230°C under a load of 2.16 kg according to ASTM D 1238. If it is in the above range, it has excellent moldability.

The thermoplastic resin (C) has a density in the range of preferably 0.825 to 0.870 g/cm ³ , more preferably 0.827 to 0.860 g/cm ³ , and even more preferably 0.830 to 0.850 g/cm ^3. When the density is in the above range, an excellent balance between flexibility and handling properties is achieved.
The thermoplastic resin (C) has a melting point Tm of 199° C. or lower, or substantially no melting point Tm as measured by a differential scanning calorimeter (DSC).

Carbodiimide modified polyolefin (D)
The carbodiimide-modified polyolefin (D) is a reaction product between a polyolefin (a) having a group reactive with a carbodiimide group and a carbodiimide group-containing compound (b).

By containing the carbodiimide-modified polyolefin (D) in the adhesive resin composition of the present invention, the adhesive resin composition of the present invention contains a carbodiimide group.
The number of carbodiimide groups in one molecule of the carbodiimide-modified polyolefin (D) is preferably 5 or more, more preferably 10 or more. The upper limit of the number of carbodiimide groups is not particularly limited as long as the effects of the present invention are exhibited, but is usually 30.

(Polyolefin (a))
The polyolefin (a) having a group reactive with a carbodiimide group can be obtained by introducing a compound (m) having a group reactive with a carbodiimide group into a polyolefin. The polyolefin (a) may be used alone or in combination of two or more kinds.

Examples of the compound (m) include compounds having a group with active hydrogen that is reactive with a carbodiimide group. Specific examples include compounds having a group derived from a carboxylic acid, an amine, an alcohol, a thiol, etc. Among these, compounds having a group derived from a carboxylic acid are preferably used, and unsaturated carboxylic acids and/or derivatives thereof are particularly preferred. In addition to compounds having a group with an active hydrogen, compounds having a group that is easily converted into a group with active hydrogen by water or the like can also be preferably used. Specific examples include compounds having an epoxy group and compounds having a glycidyl group. Compound (m) may be used alone or in combination of two or more types.

When an unsaturated carboxylic acid and/or a derivative thereof is used as compound (m), an unsaturated compound having one or more carboxylic acid groups and a derivative thereof, preferably an unsaturated compound having one or more carboxylic acid anhydride groups and a derivative thereof can be mentioned. Examples of the unsaturated group include a vinyl group, a vinylene group, and an unsaturated cyclic hydrocarbon group. Specific compounds include unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid, their acid anhydrides, and their derivatives (e.g., acid halides, amides, imides, esters, etc.). Specific acid anhydrides and derivatives include, for example, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic anhydride; malenyl chloride; malenylimide; dimethyl maleate, monomethyl maleate, diethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalate, dimethyl bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, aminoethyl (meth)acrylate, and aminopropyl (meth)acrylate.

When an unsaturated carboxylic acid and/or a derivative thereof is used as compound (m), one type may be used alone, or two or more types may be used. Among these, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic anhydride, (meth)acrylic acid, hydroxyethyl (meth)acrylate, glycidyl methacrylate, and aminopropyl methacrylate are preferred. Furthermore, dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic anhydride are particularly preferred.

As a method for introducing compound (m) into polyolefin, well-known methods can be adopted, for example, a method of graft copolymerizing compound (m) onto the polyolefin main chain, or a method of radical copolymerizing an olefin with compound (m). Below, a specific explanation is given separately for the case of graft copolymerization and the case of radical copolymerization.

<Graft copolymerization>
The polyolefin (a) having a group reactive with a carbodiimide group can be obtained by graft copolymerizing a compound (m) having a group reactive with a carbodiimide group in the polyolefin main chain, and, if necessary, other ethylenically unsaturated monomers, etc., in the presence of a radical initiator.

<Polyolefin main chain>
The polyolefin used as the polyolefin main chain is a polymer mainly composed of an aliphatic α-olefin having 2 to 20 carbon atoms, a cyclic olefin, or a non-conjugated diene, preferably an aliphatic α-olefin having 2 to 10 carbon atoms, more preferably an aliphatic α-olefin having 2 to 8 carbon atoms. These olefins may be used alone or in combination of two or more. In the case of a copolymer, the content of the olefin serving as a comonomer is not particularly limited as long as the effects of the present invention are exhibited, but is usually 50 mol% or less, preferably 40 mol% or less, and more preferably 30 mol% or less. Among the polyolefins in this range, crystalline polyolefins such as polyethylene, polypropylene, polybutene-1, poly-4-methyl-1-pentene, and α-olefin copolymers of ethylene, propylene, butene-1, or 4-methyl-1-pentene with a comonomer are preferred, and polyethylene, polypropylene, or propylene-ethylene copolymers are more preferred. In addition, both isotactic and syndiotactic structures can be used, and there is no particular restriction on the stereoregularity.

The density of the polyolefin used for graft modification (measured according to JIS K7112) is not particularly limited as long as the effects of the present invention are achieved, but is usually 0.8 to 1.1 g/cm ³ , preferably 0.8 to 1.05 g/cm ³ , and more preferably 0.8 to 1.0 g/cm ³ . The melt flow rate (MFR) at 230°C under a load of 2.16 kg according to ASTM D1238 is not particularly limited as long as the effects of the present invention are achieved, but is usually 0.01 to 500 g/10 min, preferably 0.05 to 200 g/10 min, and more preferably 0.1 to 100 g/10 min. If the density and MFR are within these ranges, the density and MFR of the graft copolymer after modification will also be approximately the same, making it easy to handle.

The degree of crystallinity of the polyolefin used for graft modification is not particularly limited as long as it achieves the effects of the present invention, but is usually 2% or more, preferably 5% or more, and more preferably 10% or more. If the degree of crystallinity is within this range, the graft copolymer after modification will be easy to handle.

The number average molecular weight (Mn) of the polyolefin used for graft modification, measured by gel permeation chromatography (GPC), is preferably 5,000 to 500,000, and more preferably 10,000 to 100,000. A number average molecular weight (Mn) within this range provides excellent handling. For ethylene-based polyolefins, the number average molecular weight can be calculated in terms of polyethylene if the comonomer amount is 10 mol% or less, and in terms of ethylene-propylene (based on an ethylene content of 70 mol%) if the comonomer amount is 10 mol% or more.

The polyolefin used for graft modification can be produced by any conventional method. For example, olefins can be polymerized using a titanium catalyst, a vanadium catalyst, a metallocene catalyst, or the like. The polyolefin used for graft modification can be in the form of either a resin or an elastomer, and both isotactic and syndiotactic structures can be used, with no particular restrictions on stereoregularity. Commercially available resins can also be used as is.

Graft Polymerization Method
The method for grafting the compound (m) onto the polyolefin main chain is not particularly limited, and any of the conventionally known graft polymerization methods such as a solution method and a melt kneading method can be used.

The graft amount of the compound (m) is usually 0.05 to 20% by weight, preferably 0.05 to 10% by weight, more preferably 0.05 to 5% by weight, and even more preferably 0.05 to 3% by weight, based on 100% by weight of the polyolefin (a). The graft amount of the compound (m) is a net graft amount measured after removing the free compound (m) from the polyolefin (a). The graft amount can be measured by known means such as ¹³ C-NMR and ¹ H-NMR measurement. When a monomer having an acidic functional group, such as an unsaturated carboxylic acid and its acid anhydride, is used as the compound (m), it is also possible to use, for example, the acid value as a measure of the amount of the functional group introduced into the polyolefin (a). When maleic anhydride is used as the compound (m), the graft amount can also be determined based on the absorption spectrum of the carbonyl group of maleic anhydride, which is usually detected around 1780 to 1790 cm using an infrared spectrophotometer.

<Radical copolymerization>
The polyolefin (a) having a group reactive with a carbodiimide group can also be obtained by radical copolymerization of an olefin and a compound (m) having a group reactive with a carbodiimide group. The olefin can be the same as the olefin used to form the polyolefin main chain described above. The method of copolymerizing the olefin and the compound (m) is not particularly limited, and any conventionally known radical copolymerization method can be used.

(Constitution of polyolefin (a))
The amount of structural units (e.g., structural unit amount, graft amount) derived from the compound (m) having a group reactive with a carbodiimide group in the polyolefin (a) having a group reactive with a carbodiimide group is usually 0.05 to 20% by weight, preferably 0.05 to 5% by weight, and more preferably 0.05 to 3% by weight. If the amount of structural units derived from the compound (m) having a group reactive with a carbodiimide group is within the above range, it is preferable because the polyolefin (a) and the carbodiimide group-containing compound (b) are suitably crosslinked to produce an adhesive. If it is below the above range, the adhesive strength may be insufficient.

The density of the polyolefin (a) having a group reactive with a carbodiimide group (measured in accordance with JIS K7112) is usually 0.870 to 0.940 g/cm ³ , preferably 0.875 to 0.940 g/cm ³ , and more preferably 0.880 to 0.940 g/cm ³ .

(Carbodiimide Group-Containing Compound (b))
The carbodiimide group-containing compound (b) is, for example, a polycarbodiimide having a repeating unit represented by general formula (2). The carbodiimide group-containing compound (b) may be used alone or in combination of two or more kinds.

In formula (2), R ₁ represents a divalent organic group having 2 to 40 carbon atoms.

Polycarbodiimide can be produced by carrying out a decarboxylation condensation reaction of organic diisocyanates such as aliphatic diisocyanates, aromatic diisocyanates, and alicyclic diisocyanates in the presence of a condensation catalyst without a solvent or in an inert solvent. For example, diisocyanates such as hexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, xylylene diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and isophorone diisocyanate can be used alone or in combination. In the decarboxylation condensation reaction, the degree of polymerization of the polycarbodiimide can be adjusted by selecting the catalyst, reaction temperature, end-capping agent, etc. The degree of polymerization is usually 2 to 40, preferably 4 to 20. Examples of the terminal blocking agent that can be used include monoisocyanates such as phenyl isocyanate, tolyl isocyanate, and naphthyl isocyanate, and active hydrogen-containing compounds such as methanol, ethanol, diethylamine, cyclohexylamine, succinic acid, benzoic acid, and ethyl mercaptan. Examples of the condensation catalyst that can be used include alcoholates of titanium, hafnium, zirconium, sodium, calcium, and the like, and organic phosphorus compounds such as phosphorene oxide.

The number average molecular weight (Mn) of the carbodiimide group-containing compound (b) calculated in terms of polystyrene, determined by gel permeation chromatography (GPC), is not particularly limited as long as the effects of the present invention are achieved, but is usually 400 to 500,000, preferably 700 to 10,000, more preferably 1,000 to 8,000, and even more preferably 1,000 to 4,000. A number average molecular weight (Mn) in this range is preferable because it provides excellent adhesive strength to the adhesive.

The carbodiimide group-containing compound (b) may contain a monocarbodiimide in a polycarbodiimide, and it is also possible to use a single compound or a mixture of a plurality of compounds.
In the present invention, a commercially available carbodiimide group-containing compound can be used as it is. Examples of commercially available carbodiimide group-containing compounds include Carbodilite (registered trademark) HMV-8CA, HMV-15CA, and Carbodilite (registered trademark) LA1 manufactured by Nisshinbo Chemical Inc.

In the present invention, the more the number of carbodiimide groups in one molecule of the carbodiimide group-containing compound (b), the more reaction sites there are with polar resins and resins such as polyketones, and therefore the layer containing the polar resin and the layer containing the resin such as polyketones can be more firmly bonded to the layer made of the adhesive of the present invention. For this reason, it is preferable to use a carbodiimide group-containing compound (b) having 5 or more carbodiimide groups in one molecule, and it is more preferable to use a carbodiimide group-containing compound (b) having 10 or more carbodiimide groups in one molecule. The upper limit of the number of carbodiimide groups in one molecule is not particularly limited as long as the effects of the present invention are achieved, but if the number of carbodiimide groups in one molecule increases, a crosslinked structure via the carbodiimide group-containing compound (b) is more likely to be formed, which may deteriorate the moldability, so 30 is preferable.

The content of carbodiimide groups in the carbodiimide group-containing compound (b) can be measured by ¹³ C-NMR, IR, titration, etc., and can be understood as a carbodiimide group equivalent. A peak can be observed at 130 to 142 ppm in ¹³ C-NMR, and at 2130 to 2140 cm ⁻¹ in IR.

^13C -NMR measurement is carried out, for example, as follows. That is, 0.35 g of a sample is heated and dissolved in 2.0 ml of hexachlorobutadiene. After filtering this solution through a glass filter (G2), 0.5 ml of deuterated benzene is added and the solution is placed in an NMR tube with an inner diameter of 10 mm. Then, ^13C -NMR measurement is carried out at 120°C using a GX-500 NMR measurement device manufactured by JEOL Ltd. The number of accumulations is 10,000 or more.

(Method of preparing polyolefin)
The carbodiimide-modified polyolefin (D) is obtained by reacting a polyolefin (a) having a group reactive with a carbodiimide group with a carbodiimide group-containing compound (b) at a temperature of preferably 230° C. or higher. The adhesive containing the polyolefin can be obtained by melt kneading, such as melt modification, but is not limited to this method.

The following is an example of melt kneading. The reaction method is not particularly limited, but examples include a method in which polyolefin (a) and carbodiimide group-containing compound (b) are charged into, for example, a Henschel mixer, V-type blender, tumbler blender, ribbon blender, etc., and kneaded, and then melt kneaded with a single-screw extruder, multi-screw extruder, kneader, Banbury mixer, etc. Among these, it is preferable to use a device with excellent kneading performance such as a multi-screw extruder, kneader, or Banbury mixer, since it is possible to obtain an adhesive in which each component is more uniformly dispersed and reacted.

The polyolefin (a) and the carbodiimide group-containing compound (b) can be mixed in advance and then fed from a hopper, or some of the components can be fed from the hopper and the other components can be fed from a feed port installed anywhere between the vicinity of the hopper and the tip of the extruder.

The temperature at which the above components are melted and kneaded can be set to the highest melting point of each component being mixed, but is typically in the range of 180 to 320°C, preferably 230 to 300°C, and more preferably 235 to 280°C.

Composition (Ia)
In the composition (Ia), a part or all of the copolymers contained in the propylene-based polymer (A), the ethylene-based polymer (B) and the thermoplastic resin (C) may be graft-modified with an unsaturated carboxylic acid and/or a derivative thereof. That is, any one or two of the components (A), (B) and (C) may be graft-modified, or all three components may be graft-modified. Also, each of the components (A), (B) and (C) may be graft-modified only partially or entirely.

Graft modification can generally be carried out by grafting an unsaturated carboxylic acid and/or its derivative to a base polymer. Examples of unsaturated carboxylic acids include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid (a registered trademark of endo-cis-bicyclo "2,2,1" hept-5-ene-2,3-dicarboxylic acid), acrylic acid, and methacrylic acid. Examples of derivatives of unsaturated carboxylic acids include acid anhydrides, imides, amides, and esters of the unsaturated carboxylic acids, and specific examples include maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, and glycidyl maleate. Among these, unsaturated carboxylic acids or their acid anhydrides are preferred, and maleic acid, nadic acid, and their acid anhydrides are particularly preferred. When using unsaturated carboxylic acids and/or their derivatives, one type may be used alone, or two or more types may be used.

For the graft reaction, a conventionally known method can be used. For example, when a propylene-based polymer is used as the base polymer, the propylene-based polymer is dissolved in an organic solvent, and then an unsaturated carboxylic acid or its derivative and, if necessary, a radical initiator such as an organic peroxide are added to the resulting solution, and the mixture is reacted for 0.5 to 15 hours, preferably 1 to 10 hours, at a temperature of 60 to 350°C, preferably 80 to 190°C. Alternatively, a method can be used in which a propylene-based polymer, an unsaturated carboxylic acid or its derivative and, if necessary, a radical initiator such as an organic peroxide are added without a solvent using an extruder, and the mixture is reacted for 0.5 to 10 minutes, usually at a temperature above the melting point of the propylene-based polymer, preferably at 120 to 350°C.

As radical initiators, organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferred.

The amount of modification by the graft modification is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and even more preferably 1 to 5% by mass, in terms of the weight of the graft monomer. If the amount of graft modification is within the above range, the interlayer adhesion of the resulting laminate will be good.

In composition (Ia), the ratio of component (A) is 45 to 75 parts by mass, the ratio of component (B) is 0 to 20 parts by mass, and the ratio of component (C) is 15 to 45 parts by mass, preferably the ratio of component (A) is 47 to 72 parts by mass, the ratio of component (B) is 7 to 20 parts by mass, and the ratio of component (C) is 17 to 42 parts by mass, and more preferably the ratio of component (A) is 50 to 70 parts by mass, the ratio of component (B) is 10 to 20 parts by mass, and the ratio of component (C) is 20 to 40 parts by mass, out of a total of 100 parts by mass of components (A), (B), and (C).

In the case where the composition (Ia) contains the component (D), the ratio of the component (A) is 45 to 65 parts by mass, the ratio of the component (B) is 0 to 20 parts by mass, the ratio of the component (C) is 15 to 45 parts by mass, and the ratio of the component (D) is 5 to 30 parts by mass, preferably the ratio of the component (A) is 45 to 60 parts by mass, the ratio of the component (B) is 5 to 17 parts by mass, the ratio of the component (C) is 17 to 42 parts by mass, and the ratio of the component (D) is 10 to 30 parts by mass, and more preferably the ratio of the component (A) is 45 to 55 parts by mass, the ratio of the component (B) is 7 to 17 parts by mass, the ratio of the component (C) is 20 to 40 parts by mass, and the ratio of the component (D) is 10 to 25 parts by mass, out of a total of 100 parts by mass of the components (A), (B), (C), and (D).

The melt flow rate (MFR) of composition (Ia) at a temperature of 230°C and a load of 2.16 kg according to ASTM D 1238 is preferably in the range of 0.3 to 20 g/10 min, more preferably in the range of 0.5 to 15 g/10 min. When it is in the above range, it has excellent moldability and sealability.

The density of the composition (Ia) measured in accordance with JIS K7112 is preferably in the range of 0.860 to 0.900 g/cm ³ , more preferably 0.865 to 0.890 g/cm ³ . When it is in the above range, the composition is excellent in flexibility and adhesiveness.

The content of carbodiimide groups in composition (Ia) is preferably 0.1 to 50 mmol, more preferably 0.2 to 40 mmol, and even more preferably 0.5 to 30 mmol per 100 g of adhesive. When the content of carbodiimide groups in composition (Ia) is within this range, it is preferable because it has excellent adhesive properties and can suppress crosslinking of polyolefin (a) via carbodiimide group-containing compound (b).

The content of carbodiimide groups in the composition (Ia) can be calculated from the amount of the carbodiimide group-containing compound (b) charged, and can also be measured by ¹³ C-NMR, IR, titration, etc., and can be understood as the carbodiimide group equivalent. A peak can be observed at 130 to 142 ppm in ¹³ C-NMR, and at 2130 to 2140 cm-1 in IR. The ¹³ C-NMR measurement is carried out, for example, by the measurement method described in the above-mentioned method for measuring the carbodiimide group content in the carbodiimide group-containing compound (b).

Carbodiimide-modified polyolefin (D) is produced by reacting the carbodiimide group (NCN) of the carbodiimide group-containing compound (b) with a group in polyolefin (a) that reacts with the carbodiimide group, as described above, and a certain amount of carbodiimide groups are consumed during this reaction. The residue of the carbodiimide group that is connected to the polyolefin group as the same molecular chain contributes to adhesion to polyketones or polar resins, etc. If the content of carbodiimide groups in composition (Ia) exceeds the above range, there will be an excess of free carbodiimide groups in composition (Ia) relative to the carbodiimide-modified polyolefin (D), and the adhesive performance and moldability will decrease.

The reaction rate between the polyolefin (a) and the carbodiimide group-containing compound (b) can be evaluated by the following method.
For the polyolefin (a) (reference) having a group reactive with the carbodiimide group and the composition (Ia), each heat press sheet is prepared, and then infrared absorption is measured using an infrared absorption analyzer. From the obtained chart, the difference between the absorbance derived from the group reactive with the carbodiimide group in the polyolefin (a), the absorbance derived from the group reactive with the carbodiimide group in the polyolefin (a) and the absorbance derived from the group reactive with the carbodiimide group in the adhesive can be compared, and the reaction rate can be calculated using the following formula (α1). In addition, when a group derived from maleic anhydride is used as the group reactive with the carbodiimide group, the absorbance near 1790 cm ^-1 can be used.

Reaction rate (%) = {P / Q} × 100 ... formula (α1)
P: The difference between the absorbance derived from the group in the polyolefin (a) that reacts with the carbodiimide group and the absorbance derived from the group in the adhesive that reacts with the carbodiimide group. Q: The absorbance derived from the group in the polyolefin (a) that reacts with the carbodiimide group. The reaction rate of the adhesive determined by the above method is usually in the range of 40 to 100%, preferably 60 to 100%, and more preferably 80 to 100%.

The carbodiimide group is converted to a urea group by absorbing water, but the urea group also exhibits high reactivity with polyketones or polar resins. Therefore, the adhesive may contain polyolefins in which the carbodiimide group has been converted to a urea group by, for example, water in the air, which is one of the preferred embodiments of the present invention.

Composition (Ia) can be prepared by various known methods, such as a method of dry blending the above components using a Henschel mixer, tumbler blender, V-blender, or the like, a method of dry blending and then melt kneading using a single-screw extruder, multi-screw extruder, Banbury mixer, or the like, and a method of stirring and mixing in the presence of a solvent.

Composition (Ia) may contain, as necessary, additives such as commonly used antioxidants, weather stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, pigments, or other polymers, rubbers, etc., within the scope of the present invention.

<Metal Layer (II)>
The metal constituting the metal layer (II) is not particularly limited, and may be, for example, aluminum, titanium, copper, nickel, or an alloy containing at least one selected from these.For example, when the metal layer (II) is a lead base material of a tab lead connected to the positive electrode of a lithium ion battery, the metal layer (II) is preferably made of aluminum, titanium, or an alloy containing at least one selected from these.When the metal layer (II) is a lead base material of a tab lead connected to the negative electrode of a lithium ion battery, the metal layer (II) is preferably made of copper, nickel, or an alloy containing at least one selected from these.

The metal layer (II) is, for example, a metal sheet or a metal plate. One embodiment of the metal layer (II) is a lead substrate constituting a tab lead connected to an electrode selected from the positive electrode and the negative electrode of a lithium ion battery.

<Polyolefin resin layer (III)>
The composite of the present invention may further have a polyolefin resin layer (III). The polyolefin resin layer (III) is formed, for example, on the surface of the composition layer (I) that is not in contact with the metal layer (II). That is, the composite of the present invention may have a configuration of metal layer (II)/composition layer (I)/polyolefin resin layer (III).

The polyolefin resin in the polyolefin resin layer (III) may be, for example, a thermoplastic polyolefin resin such as polyethylene, polypropylene, or 4-methyl-1-pentene polymer. These may be used alone or in combination of two or more. The polyolefin resin may be crosslinked. From the viewpoint of heat resistance, the polyolefin resin in the polyolefin resin layer (III) is preferably a 4-methyl-1-pentene polymer.

The 4-methyl-1-pentene polymer preferably contains 90 mol% to 100 mol% of structural units derived from 4-methyl-1-pentene, more preferably 92 mol% to 100 mol%, and even more preferably 95 mol% to 100 mol% of all structural units. The 4-methyl-1-pentene polymer preferably contains 0 mol% to 10 mol% of structural units derived from α-olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene, more preferably 0 mol% to 8 mol%, and even more preferably 0 mol% to 5 mol% of all structural units. Examples of α-olefins having 2 to 20 carbon atoms other than 4-methyl-1-pentene include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene, and 1-octadecene.

The 4-methyl-1-pentene polymer preferably has a melting point Tm measured by a differential scanning calorimeter (DSC) of 200°C or higher, more preferably 210 to 240°C, and even more preferably 220 to 235°C.

<Other Layers (IV)>
The composite of the present invention may further have another layer (IV). The other layer (IV) is formed, for example, on the surface of the polyolefin resin layer (III) that is farther from the metal layer (II). That is, the composite of the present invention may have a configuration of metal layer (II)/composition layer (I)/polyolefin resin layer (III)/other layer (IV).

The other layer (IV) is preferably a layer formed from the above-mentioned composition (Ia). When the other layer (IV) is a layer formed from the composition (Ia), it is preferable that a polyolefin resin layer, particularly a polypropylene-based resin layer, is further formed on the surface thereof, since this provides excellent adhesive strength. The other layer (IV) may be a layer having the same composition as the composition layer (I), or may be a layer having a different composition.

In another embodiment, the other layer (IV) contains, for example, at least one resin selected from known acid-modified polyolefin resins and crosslinked products thereof. Examples of the acid-modified polyolefin resin include acid-modified thermoplastic polyolefin resins such as acid-modified polyethylene and acid-modified polypropylene. These may be used alone or in combination of two or more. The use of acid-modified polypropylene is preferable from the viewpoint of heat resistance.

<Complex Structure>
The composition of the complex of the present invention is, for example,
metal layer (II)/composition layer (I),
Metal layer (II)/composition layer (I)/polyolefin resin layer (III),
Metal layer (II)/composition layer (I)/polyolefin resin layer (III)/other layer (IV),
composition layer (I)/metal layer (II)/composition layer (I),
Polyolefin resin layer (III) / composition layer (I) / metal layer (II) / composition layer (I) / polyolefin resin layer (III);
Other layer (IV) / polyolefin resin layer (III) / composition layer (I) / metal layer (II) / composition layer (I) / polyolefin resin layer (III) / other layer (IV)
Metal layer (II) / composition layer (I) (layer formed from composition (Ia)) / polyolefin resin layer (III) / composition layer (I) (layer formed from composition (Ia))
Examples include:

In the composite of the present invention, the composition layer (I) does not need to be formed on the entire surface of the metal layer (II), but only needs to be formed on a part of the metal layer (II). For example, in the case of a tab lead for a lithium ion battery described later, it is preferable that the composition layer (I) is formed so as to cover the metal layer (II) (corresponding to the lead substrate) in the area sealed by the exterior member.

<Thickness of each layer of the composite and method of manufacturing the composite>
The complex of the present invention can be produced, for example, by the following method.
When the composition layer (I) is used alone, a film or sheet is formed from the composition (Ia) using a molding machine such as a T-die extrusion molding machine or an inflation molding machine. The molding temperature is, for example, 180 to 250°C. Next, the film or sheet corresponding to the composition layer (I) and a metal member corresponding to the metal layer (II) are bonded together and heat-sealed, specifically, thermocompression-bonded. At this time, the thickness of the composition layer (I) is usually 5 to 300 μm, preferably 10 to 250 μm.

When the polyolefin resin layer (III) and, if necessary, other layers (IV) are provided, films corresponding to the above (I), the above (III), and, if necessary, the above (IV) are molded in advance, and then subjected to heat compression bonding or the like to produce a laminated film. Alternatively, the laminated film may be produced by molding the composition layer (I), the polyolefin resin layer (III), and, if necessary, the other layers (IV) by a known multilayer molding method. Known multilayer molding methods include, for example, coextrusion molding and extrusion lamination. In this case, the total thickness of the composition layer (I), the polyolefin resin layer (III), and, if necessary, the other layers (IV) is usually 10 to 300 μm, preferably 10 to 250 μm. Among these, the thickness of the composition layer (I) is usually 3 to 50 μm, preferably 5 to 40 μm, the thickness of the polyolefin resin layer (III) is, for example, 7 to 297 μm or 5 to 245 μm, and the thickness of the other layer (IV) is usually 3 to 50 μm, preferably 5 to 40 μm. Next, the laminated film and a metal member corresponding to the metal layer (II) are bonded together so that the composition layer (I) is in contact with the metal layer (II), and are heat-sealed, specifically, heat-pressed.

The thickness of the metal layer (II) is not particularly limited and may be appropriately selected depending on the desired application, but is preferably 2 μm to 100 mm, more preferably 5 μm to 50 mm.
The conditions for heat fusion, specifically the conditions for heat compression, are, for example, usually 130 to 200° C., preferably 140 to 180° C., and usually 0.1 to 1 MPa, preferably 0.2 to 0.8 MPa.

Among these, it is particularly preferable to use the composite of the present invention as a tab lead. A tab lead is a terminal in a battery that transfers electricity between an electrode and the outside. It is preferable to use the composite of the present invention as a tab lead for a lithium ion battery, particularly for a laminated lithium ion battery. A laminated lithium ion battery is lightweight for a lithium ion battery, has a high degree of freedom in shape, and is capable of high-speed charging.

The tab lead of the present invention has a metal layer (II) that is a lead substrate, and a tab lead film formed on at least one side of the lead substrate. The tab lead can have tab lead films on both sides of the lead substrate.

The tab lead film has a composition layer (I) in contact with the lead substrate, and in one embodiment, a polyolefin resin layer (III) and, if necessary, other layers (IV) can be further provided on the composition layer (I). The tab lead film is formed to cover a part of the lead substrate (lead conductor) and to adhere to the inner surface of the exterior member of the lithium ion battery described below. As an example, FIG. 1 shows a configuration in which the lead substrate and the exterior member are adhered by the tab lead film.

In one embodiment, the tab lead film is a laminated film having a heat-resistant layer and an adhesive layer. In a lithium ion battery, the adhesive layer is adhered to a lead substrate, and the heat-resistant layer is adhered to the inner surface of an exterior member. In one embodiment, the metal layer (II) in the composite of the present invention corresponds to the lead substrate, the composition layer (I) corresponds to the adhesive layer of the tab lead film, and the polyolefin resin layer (III) corresponds to the heat-resistant layer of the tab lead film.

Examples of materials constituting the lead substrate include aluminum, titanium, copper, nickel, and alloys containing at least one selected from these. For example, a lead conductor made of aluminum, titanium, and an alloy containing at least one selected from these is used as the lead substrate connected to the positive electrode of the lithium ion battery, and for example, a lead conductor made of copper, nickel, and an alloy containing at least one selected from these is used as the lead substrate connected to the negative electrode of the lithium ion battery.

[Lithium-ion battery]
The lithium ion battery of the present invention has the above-mentioned tab lead.
Specifically, the lithium ion battery of the present invention has a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, an electrolyte, and an exterior member that contains (i.e., encapsulates) these. The lithium ion battery has a positive electrode tab lead electrically connected to the positive electrode, and a negative electrode tab lead electrically connected to the negative electrode.

The positive electrode, negative electrode, and separator may have a conventionally known configuration. The positive electrode and negative electrode each have, for example, a metal substrate called a current collector, and an active material layer on the metal substrate. The metal substrate of the positive electrode may be, for example, an electrode conductor made of aluminum, titanium, or an alloy containing at least one selected from these. The metal substrate of the negative electrode may be, for example, an electrode conductor made of copper, nickel, or an alloy containing at least one selected from these. The separator may be, for example, a polyolefin-based porous film. The electrodes in a lithium-ion battery may be a stacked electrode group in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween.

The electrolytic solution may be a non-aqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent. Examples of the electrolyte include lithium compounds such as LiClO ₄ , LiBF ₄ , LiPF ₆ , and LiAsF _6. Examples of the organic solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, and tetrahydrofuran.

In order to extract current from the lithium-ion battery to the outside, i.e., to enable electrical connection to the outside, the positive electrode tab lead and the negative electrode tab lead extend from inside the exterior member to the outside. Specifically, the metal substrate of the positive electrode is electrically connected to one end of the positive electrode tab lead, and the other end of the positive electrode tab lead extends to the outside of the exterior member. In addition, the metal substrate of the negative electrode is electrically connected to one end of the negative electrode tab lead, and the other end of the negative electrode tab lead extends to the outside of the exterior member.

In the lithium ion battery of the present invention, the tab lead of the present invention is used for at least some of the tab leads. At the portion where the tab lead is taken out from the exterior member, a portion of the lead base material and the exterior member are joined by heat fusion of the tab lead film. The sealing property of the exterior member may decrease at the portion where the tab lead is taken out, but in the present invention, the heat fusion can prevent the sealing property of the exterior member from decreasing. Furthermore, in the present invention, the adhesive strength of the seal is high and excellent.

The exterior member is usually a bag-shaped member made of a laminate sheet having a metal layer, i.e., a laminate packaging material. The laminate sheet has a metal layer made of a metal such as aluminum, copper, or stainless steel, and a resin film formed on both sides of the metal layer. This configuration improves the sealing performance of the exterior member.

The innermost film of the exterior member (the resin film on the inside of the battery) comes into contact with the nonaqueous electrolyte, and is therefore made of, for example, polypropylene, which has excellent heat sealability, in order to prevent the nonaqueous electrolyte from leaking from the sealed portion. The outermost film of the exterior member (the resin film on the outside of the battery) is made of, for example, a polyester, such as polyethylene terephthalate, in order to protect the metal layer from external damage.

The exterior member can be formed by heat-sealing the peripheral seal portions of two of the laminate sheets cut into a rectangular shape. For example, three sides of the rectangular peripheral portions of the two laminate sheets are heat-sealed to the desired seal width. In this way, an exterior member with an opening is obtained, with three sides sealed and one side open.

Next, the components of the lithium ion battery and a part of the tab lead are placed inside an exterior member having an opening through the opening. Next, the part of the tab lead where the tab lead film is formed is sandwiched between the exterior members at the opening end and heat sealed. In this way, the lithium ion battery of the present invention can be obtained.

(Various measurement methods)
In the present examples, measurements were carried out according to the following method.

[Melt flow rate (MFR) of adhesive resin composition]
The melt flow rate of the adhesive resin composition was measured under the following conditions in accordance with ASTM D1238.
Polyethylene polymer: 190° C., under a load of 2.16 kg Polypropylene polymer: 230° C., under a load of 2.16 kg 4-methyl-1-pentene polymer: 260° C., under a load of 5 kg.

[density]
The density was measured in accordance with JIS K7112.

[Number average molecular weight of carbodiimide group-containing compound]
The number average molecular weight was measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent (mobile phase) at a column temperature of 40° C. (polystyrene equivalent, Mw: weight average molecular weight, Mn: number average molecular weight). For standard polystyrene with a molecular weight of 580≦Mw≦7×10 ⁶ , polystyrene PS-1 manufactured by Agilent Technologies Inc. (formerly Polymer Laboratories Limited) was used.

[Carbodiimide group content]
The carbodiimide group content in the examples and comparative examples was calculated from the charged amount of the carbodiimide group-containing compound.

[Grafting amount of maleic anhydride]
The graft amount of maleic anhydride was measured by FT-IR as follows: A sample was heat-pressed at 250° C. for 3 minutes to prepare a sheet, and then an infrared absorption spectrum was measured at about 1790 cm ⁻¹ by a transmission method using an infrared spectrophotometer (FT-IR410, manufactured by JASCO Corporation). The measurement conditions were a resolution of 2 cm ⁻¹ and an accumulation number of 32 times.

The polyolefins used in the examples and comparative examples are shown below. The propylene polymer (A), ethylene polymer (B) and thermoplastic resin (C) were all prepared by polymerization according to conventional methods.

Propylene-based polymer (A)
PP-1: Random polypropylene (melt flow rate (230° C., 2.16 kg load): 7.0 g/10 min, density: 0.900 g/cm ³ , propylene content: 95 mol %, ethylene content: 5 mol %)
PP-2: Maleic anhydride modified homopolypropylene (melt flow rate (230° C., 2.16 kg load): 100 g/10 min, density: 0.900 g/cm ³ , maleic anhydride graft amount: 3.0% by mass)
PP-3: Polypropylene (melt flow rate (230° C., 2.16 kg load): 5 g/10 min, density: 0.900 g/cm ³ , propylene content: 96 mol %, ethylene content: 4 mol %)

Ethylene polymer (B)
PE-1: Polyethylene polymer (melt flow rate (190° C., 2.16 kg load): 0.8 g/10 min, density: 0.870 g/cm ³ , propylene content: 19 mol %)

Thermoplastic resin (C)
PMP-1: propylene-4-methyl-1-pentene copolymer (MFR: 10 g/10 min (230° C., 2.16 kg load), density: 0.838 g/cm ³ , propylene content: 15 mol %, 4-methyl-1-pentene content: 85 mol %, melting point measured by DSC: 130° C.)
PMP-2: propylene-4-methyl-1-pentene copolymer (MFR: 10 g/10 min (230° C., 2.16 kg load), density: 0.840 g/cm ³ , propylene content: 28 mol %, 4-methyl-1-pentene content: 72 mol %, no melting point observed by DSC)

Carbodiimide-modified polyolefin (D)
CDI-PP1: Carbodiimide-modified polyolefin obtained by Production Example 1 below

[Production Example 1]
<Production of polyolefin (a) having a group reactive with a carbodiimide group>
100 parts of PP-1 was mixed with 1 part of maleic anhydride (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter abbreviated as MAH) and 0.25 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3 (manufactured by NOF Corporation, trade name Perhexyne (registered trademark) 25B), and extruded using a twin-screw kneader at a cylinder temperature of 220°C, a screw rotation speed of 200 rpm, and a discharge rate of 80 g/min to obtain maleic anhydride-modified polypropylene (hereinafter abbreviated as MAH-PP-1), which is polyolefin (a). The density of MAH-PP-1 was 0.905 g/cm ³ .

The obtained MAH-PP-1 was dissolved in xylene, and then the obtained xylene solution was poured into acetone to reprecipitate and purify MAH-PP-1. The amount of maleic anhydride grafted was measured by FT-IR and found to be 0.7% by weight.

<Production of Carbodiimide-Modified Polyolefin (D)>
100 parts of the MAH-PP-1 produced above and 8.8 parts of a carbodiimide group-containing compound (manufactured by Nisshinbo Chemical Inc., trade name Carbodilite (registered trademark) HMV-15CA, carbodiimide group equivalent: 262, number average molecular weight: 3050, number of carbodiimide groups per molecule: 12) were mixed and extruded using a twin-screw kneader at a cylinder temperature of 250° C., a screw rotation speed of 200 rpm, and a discharge rate of 80 g/min to produce pellets of carbodiimide-modified PP (hereinafter abbreviated as CDI-PP1), which is a carbodiimide-modified polyolefin (D).

The obtained CDI-PP1 had an MFR (230°C, 2.16 kg load) of 130 g/10 min, a density of 0.905 g/ ^cm3 , and a carbodiimide group content calculated from the amount of the carbodiimide group-containing compound charged of 31 mmol/100 g. According to FT-IR analysis, the peak of maleic anhydride (1790 cm ^-1 ) disappeared from CDI-PP1, and therefore the ratio of the difference (P) between the absorbance attributable to the group reactive with the carbodiimide group in polyolefin (a) and the absorbance attributable to the group reactive with the carbodiimide group in CDI-PP1 to the absorbance (Q) attributable to the group reactive with the carbodiimide group in polyolefin (a) was 1, and therefore the reaction rate was 100%.

Example 1
<Production of Resin Composition>
65 parts of the above PP-1, 5 parts of PP-2, and 30 parts of PMP-2 were mixed and melt-kneaded at 230° C. using a twin-screw kneader (TEX-30, manufactured by Japan Steel Works, Ltd.) to obtain composition Ia-
The resulting composition had a melt flow rate of 8.3 g/10 min and a density of 0.880 g/cm ³ .

<Production of Laminate>
Compositions Ia-1 and MP-1 (poly 4-methyl-1-pentene (MFR: 26 g/
The layers consisting of 100% 4-methyl-1-pentene (100% by weight, 260° C., 5 kg load, density: 0.833 g/cm ³ , 100 mol % 4-methyl-1-pentene content, melting point measured by DSC: 220° C.) were coextruded under the following conditions to form a three-layer laminate:

Composition I was co-extruded using a T-die cast sheet molding machine (manufactured by EDI Co., Ltd.).
A laminate of Ia-1/MP-1/composition Ia-1 was prepared. The extruder temperature of the composition Ia-1 layer was set to 230° C., the extruder temperature of the MP-1 layer was set to 275° C., the die temperature was set to 275° C., and the laminate was taken up at a speed of 4 m/min while being cooled by a chill roll. The thickness of each layer was composition Ia-1/MP-1/composition Ia-1=30/30/30 μm.

The interlayer adhesion of the laminate was evaluated by the following method. The results are shown in Table 1. Composition I
When the a-1 layer and the MP-1 layer were not peeled off, it was indicated as "not peeled off."

<Evaluation of Interlayer Adhesion Strength of Laminate>
The obtained laminate was cut into a width of 15 mm, and the interlayer adhesive strength at the interface between the composition Ia-1 layer and the MP-1 layer (MP-1 interlayer adhesive strength) was measured at room temperature of 23°C by the T-peel method using a tensile tester (IM-20ST type manufactured by Intesco Co., Ltd.).
The crosshead speed was 300 mm/min.
The unit of interlayer adhesive strength is N/15 mm.

<Production of the Complex>
The three-layer laminate obtained above was sandwiched between an aluminum sheet having a thickness of 350 μm and a width of 15 mm and a PP film having a thickness of 100 μm and a width of 15 mm, and heat-sealed for 4 seconds using a heat sealer under conditions of 140° C. and 0.2 MPa to produce a PP film/three-layer laminate/aluminum sheet composite.
The interlayer adhesion of the composite was evaluated by the following method, and the results are shown in Table 1.

<Evaluation of Interlayer Adhesion Strength of Composite>
The interlayer adhesive strength (aluminum interlayer adhesive strength) at the interface between the aluminum sheet and the three-layer laminate of the obtained composite was measured at room temperature of 23°C.
The crosshead speed was 200 mm/min.
The unit of interlayer adhesive strength is N/15 mm.

The interlayer adhesive strength (PP interlayer adhesive strength) at the interface between the PP film of the obtained composite and the three-layer laminate was measured at room temperature of 23°C.
The crosshead speed was 200 mm/min.
The unit of interlayer adhesive strength is N/15 mm.

[Examples 2 to 5, Comparative Examples 1 and 2]
Resin compositions, laminates and composites were produced in the same manner as in Example 1 according to the formulations shown in Table 1. The melt flow rates and densities of the resulting compositions, and the interlayer adhesive strengths of the laminates and composites were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 6
<Production of Composition>
20 parts of CDI-PP1, 45 parts of PP-3, 10 parts of PE-1, and 25 parts of PMP-2 were mixed and extruded using a twin-screw extruder at a cylinder temperature of 250° C., a screw rotation speed of 200 rpm, and a discharge rate of 80 g/min to obtain composition Ia-6. The melt flow rate and density of composition Ia-6 are shown in Table 1.

<Production of Laminate>
Layers of compositions Ia-6 and MP-1 were coextruded under the following conditions to form a three-layer laminate.

Composition I was co-extruded using a T-die cast sheet molding machine (manufactured by EDI Co., Ltd.).
A laminate of Ia-6/MP-1/composition Ia-6 was prepared. The extruder for the composition Ia-6 layer was set at 270° C., the extruder for the MP-1 layer was set at 275° C., the die temperature was set at 275° C., and the laminate was taken up at a speed of 4 m/min while being cooled by a chill roll. The thickness of each layer was composition Ia-6/MP-1/composition Ia-6=30/30/30 μm.

<Evaluation of Interlayer Adhesion Strength of Laminate>
The interlayer adhesive strength of MP-1 of the resulting laminate was measured in the same manner as in Example 1. The results are shown in Table 1.

<Production of the Complex>
The three-layer laminate obtained above was sandwiched between an aluminum sheet having a thickness of 350 μm and a width of 15 mm and a PP film having a thickness of 100 μm and a width of 15 mm, and heat sealed with a heat sealer at 250° C. and 0.2 MPa for 4 seconds.

<Evaluation of Interlayer Adhesion Strength of Composite>
The adhesive strength between the aluminum layers and the adhesive strength between the PP layers of the obtained composite were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 7
Compositions, laminates and composites were produced in the same manner as in Example 6 according to the formulations shown in Table 1. The melt flow rates and densities of the resulting compositions, and the interlayer adhesive strengths of the laminates and composites were measured in the same manner as in Example 1. The results are shown in Table 1.

10... Lead substrate (metal layer (II))
20... Tab lead film 21... Composition layer (I)
22...Polyolefin resin layer (III)
23...Other layers (IV)
30...Exterior member

Claims (7)

A composition layer (I) formed from a composition (Ia);
a metal layer (II) in contact with the composition layer (I);
a polyolefin resin layer (III) formed on a surface of the composition layer (I) that is not in contact with the metal layer (II);
is a complex having
The composition (Ia) comprises
the content ratio of the propylene-based polymer (A) containing 75 to 100 mol % of structural units derived from propylene is 45 to 75 parts by mass,
The content of the ethylene polymer (B) is 0 to 20 parts by mass,
A composite comprising a copolymer having 60 mol% or more and 99 mol% or less of structural units derived from 4-methyl-1-pentene and 1 mol% or more and 40 mol% or less of structural units derived from an α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms, wherein the structural units derived from 4-methyl-1-pentene and the structural units derived from an α-olefin other than 4-methyl-1-pentene and having from 2 to 20 carbon atoms are 100 mol% in total, and the content of a thermoplastic resin (C) having a melting point Tm of 199°C or less or substantially no melting point measured by a differential scanning calorimeter (DSC) is 15 to 45 parts by mass (wherein the total of ( A), (B) and (C) is taken as 100 parts by mass). 2. The composite according to claim 1, wherein a part or all of the polymers contained in the propylene-based polymer (A), the ethylene-based polymer (B) and the thermoplastic resin (C) are graft-modified with an unsaturated carboxylic acid and/or a derivative thereof. 3. The composite according to claim 1 or 2, further comprising the composition layer (I) formed on a surface of the polyolefin resin layer (III) that is not in contact with the composition layer (I). The composite according to any one of claims 1 to 3, wherein the polyolefin resin layer (III) contains a polymer in which the content ratio of structural units derived from 4-methyl-1-pentene to all structural units is 90 mol% or more and 100 mol% or less, and the content ratio of structural units derived from α-olefins other than 4-methyl-1-pentene to all structural units is 0 mol% or more and 10 mol% or less, and contains a thermoplastic resin having a melting point Tm of 200°C or more as measured by a differential scanning calorimeter (DSC). The composition (Ia) further contains a carbodiimide-modified polyolefin (D), and in the composition (Ia), the content of ( A) is 45 to 65 parts by mass , the content of (B) is 0 to 20 parts by mass, the content of ( C) is 15 to 45 parts by mass , and the content of (D) is 5 to 30 parts by mass, per 100 parts by mass of the total of (A ), (B), (C) , and ( D). The composite according to any one of claims 1 to 4. A tab lead for a lithium ion battery comprising the composite according to any one of claims 1 to 5. A lithium ion battery having the tab lead according to claim 6.