JP6430854B2 - Process for producing conjugated diene polymer - Google Patents

Description

  The present invention relates to a method for producing a conjugated diene polymer.

  A conjugated diene polymer obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer using an organic alkali metal and / or organic alkaline earth metal as a polymerization initiator in a hydrocarbon solvent is, for example, a tire. It is used as a tread material and has recently attracted attention as a material suitable for improving the fuel economy of a tire. As the hydrocarbon solvent used in the production of the conjugated diene polymer, a hydrocarbon solvent having 6 carbon atoms (hereinafter also simply referred to as C6) is mainly used from the viewpoint of the solubility of the polymer and the solvent recoverability. .

  Patent Document 1 (Japanese Patent Laid-Open No. 63-186748) describes a method for producing a modified rubber composition using normal hexane as a hydrocarbon solvent. Patent Document 2 (Japanese Patent Laid-Open No. 63-66246) describes a method for producing a rubber composition using cyclohexane as a hydrocarbon solvent.

JP-A 63-186748 JP-A 63-66246

  However, the production methods described in the above documents have a problem that it is difficult to reduce both the amount of the gel component and the amount of the residual solvent contained in the resulting conjugated diene polymer. It became clear by analysis. That is, when only the acyclic aliphatic C6 component (component consisting of an aliphatic hydrocarbon having 6 carbon atoms having no ring structure) is used as a solvent, a polymer having a high molecular weight is deposited and adhered to the inner wall of the polymerization tank. There is a problem that the resulting conjugated diene polymer remains as a gel component. On the other hand, if only the cycloaliphatic C6 component (the component consisting of an aliphatic hydrocarbon having 6 ring carbons having at least one ring structure) is used as a solvent, the polymer having a high molecular weight is deposited on the inner wall of the polymerization tank. However, there is a problem that the devolatilization rate in the desolvation process is slow and it is likely to remain as a residual volatile component.

  Then, an object of this invention is to provide the manufacturing method of the conjugated diene polymer which can reduce both the quantity of the gel component contained in the conjugated diene polymer obtained, and the quantity of a residual solvent.

The present invention relates to the following matters.
1. Production of a conjugated diene polymer comprising a step of polymerizing a conjugated diene monomer or polymerizing a conjugated diene monomer and an aromatic vinyl monomer using an organic alkali metal and / or organic alkaline earth metal as a polymerization initiator in a hydrocarbon solvent A method,
The manufacturing method of the conjugated diene polymer in which the said hydrocarbon solvent contains 1-30 mass% of the cycloaliphatic C6 component which consists of a C6 cycloaliphatic hydrocarbon with respect to the mass of all the hydrocarbon solvents.

2. 2. The conjugate according to 1 above, wherein the hydrocarbon solvent contains 70 to 99% by mass of an acyclic aliphatic C6 component composed of an acyclic aliphatic hydrocarbon having 6 carbon atoms based on the mass of the total hydrocarbon solvent. A method for producing a diene polymer.

3. 3. The method for producing a conjugated diene polymer according to 1 or 2 above, wherein the cycloaliphatic C6 component contains cyclohexane and methylcyclopentane.

4). The manufacturing method of the conjugated diene polymer in any one of said 1-3 whose said cycloaliphatic C6 component contains 5-80 mass% methylcyclopentane with respect to the total mass of cycloaliphatic C6 component.

  According to the method for producing a conjugated diene polymer of the present invention, a conjugated diene polymer having a low content of gel components and residual solvent can be obtained.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

  One aspect of this embodiment is a step of polymerizing a conjugated diene monomer or polymerizing a conjugated diene monomer and an aromatic vinyl monomer using an organic alkali metal and / or organic alkaline earth metal as a polymerization initiator in a hydrocarbon solvent. (Hereinafter, also referred to as “polymerization step”), wherein the hydrocarbon solvent is a cycloaliphatic C6 component comprising a cycloaliphatic hydrocarbon having 6 carbon atoms. 1-30 mass% is included with respect to the mass of all the hydrocarbon solvents. In the present specification, the hydrocarbon solvent may be simply referred to as “solvent”.

<Hydrocarbon solvent>
The hydrocarbon solvent used in the polymerization step for polymerizing the conjugated diene monomer or polymerizing the conjugated diene monomer and the aromatic vinyl monomer is a cycloaliphatic C6 component in an amount of 1 to 30 mass relative to the mass of the total hydrocarbon solvent. %contains. Here, in the present invention, the “cycloaliphatic C6 component” refers to a component composed of a compound having 6 carbon atoms and having at least one ring structure in the molecule. The compound contained in the cycloaliphatic C6 component may have an unsaturated bond in the molecule.

  As the compound contained in the cycloaliphatic C6 component, for example, at least one compound selected from the group consisting of cyclohexane, cyclohexene, methylcyclopentane, and methylcyclopentene can be used. The cycloaliphatic C6 component preferably contains cyclohexane and / or methylcyclopentane, more preferably cyclohexane and methylcyclopentane.

  The amount of the cycloaliphatic C6 component contained in the hydrocarbon solvent is 1 to 30% by mass with respect to the mass of the total hydrocarbon solvent. When the amount of the cycloaliphatic C6 component contained in the hydrocarbon solvent is 1% by mass or more, the content of the gel contained in the conjugated diene copolymer is suppressed, and when it is 30% by mass or less, the conjugated diene copolymer is contained. The solvent remaining in the polymer can be suppressed to a small amount. The lower limit of the content of the cycloaliphatic C6 component may be 1% by mass or more in all hydrocarbon solvents, 3% by mass, 6% by mass, 12% by mass, 14% by mass, The upper limit value may be 30% by mass or less in the total hydrocarbon solvent, and may be 27% by mass or less, 24% by mass or less, and 14% by mass or less. 12 mass% or less, 6 mass% or less, or 3 mass% or less. The content of the cycloaliphatic C6 component is preferably, for example, from 14 to 30% by mass, more preferably from 24 to 27% by mass, based on the mass of the total hydrocarbon solvent, particularly from the viewpoint of reducing the gel content. Especially from the viewpoint of reducing the amount of residual solvent, it is preferably 5 to 15% by weight, more preferably 6 to 14% by weight.

  In one Embodiment of this invention, it is preferable that cycloaliphatic C6 component contains 5-80 mass% methylcyclopentane with respect to the total mass of cycloaliphatic C6 component. The lower limit of the content of methylcyclopentane is not limited, but among the cycloaliphatic C6 component, preferably 5% by mass or more, 10% by mass or more, 30% by mass or more, 50% by mass or more, or 70% by mass. Although the upper limit value is not limited, among the cycloaliphatic C6 components, it is preferably 80% by mass or less, 75% by mass or less, 50% by mass or less, or 15% by mass or less. it can.

  Since the cycloaliphatic C6 component has a relatively high affinity with the conjugated diene polymer among the solvents, the solubility of the polymer is also high, and the precipitation and adhesion of the polymer having a high molecular weight on the inner wall of the polymerization tank is suppressed, It is thought that the formation of gel is prevented. However, since the cycloaliphatic C6 component has a high affinity with the conjugated diene polymer, the devolatilization rate in the desolvation step is slow and it tends to remain as a residual volatile component. By making the composition of the cycloaliphatic C6 component in the solvent into a specific range according to the present invention, the reduction in the amount of gel produced and the reduction in the amount of residual volatile components were achieved.

  In addition to the cycloaliphatic C6 component described above, the hydrocarbon solvent is derived from other components such as an aromatic component, an acyclic aliphatic component, and a cycloaliphatic component other than the cycloaliphatic C6 component. You may further contain at least 1 type chosen from the group which consists of. Here, the cycloaliphatic components other than the aromatic component, the acyclic aliphatic component, and the cycloaliphatic C6 component are the aromatic compound, the acyclic aliphatic compound, and the cycloaliphatic C6 component, respectively. It is a component which consists of cycloaliphatic compounds other than. Of these, the hydrocarbon solvent preferably contains an acyclic aliphatic component. The acyclic aliphatic component is preferably an acyclic aliphatic C6 component. Here, the “acyclic aliphatic C6 component” means an aliphatic hydrocarbon having 6 carbon atoms and having no ring structure in the molecule. The acyclic aliphatic C6 component may have an unsaturated bond in the molecule. As one aspect of the present embodiment, the amount of the acyclic aliphatic C6 component is preferably 70 to 99% by mass with respect to the total amount of the hydrocarbon solvent.

  Examples of the acyclic aliphatic C6 component include at least selected from the group consisting of n-hexane, hexene, 2,2-dimethylbutane, 2,3-dimethylbutane, 2-methylpentane, and 3-methylpentane. One compound can be used, and one kind may be used alone, or two or more kinds may be used in combination.

  As the aromatic component, for example, at least one compound selected from the group consisting of toluene, xylene, and ethylbenzene can be used, and one kind may be used alone, or two or more kinds may be used in combination.

<Conjugated diene monomer>
In the present invention, the conjugated diene monomer is not particularly limited as long as it is a polymerizable monomer. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3- Examples include methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of industrial availability. These may be used alone or in combination of two or more.

  In the present embodiment, the conjugated diene monomer and the aromatic vinyl monomer may be copolymerized to produce a conjugated diene polymer that is a copolymer thereof. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene monomer. For example, styrene, m or p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, And divinylbenzene. Among these, styrene is preferable from the viewpoint of industrial availability. These may be used individually by 1 type and may use 2 or more types together.

<Conjugated diene polymer>
The conjugated diene polymer produced in the present embodiment may be a polymer containing only a conjugated diene monomer, or may be a polymer (copolymer) of a conjugated diene monomer and an aromatic vinyl monomer. These polymers may be polymerized with other polymerizable monomers. In addition, each of the conjugated diene monomer and the aromatic vinyl monomer may be a single compound or two or more compounds.

  When the conjugated diene polymer is a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of the aromatic vinyl monomer bonded to the conjugated diene polymer (hereinafter referred to as “bound aromatic vinyl amount”). Is not particularly limited, but is preferably 5% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 50% by mass or less, with respect to 100% by mass of the total amount of the conjugated diene polymer. When the amount of bonded aromatic vinyl is in the above range, when the obtained conjugated diene polymer is used as a material for, for example, a tire tread, the balance between low hysteresis loss and wet skid resistance is further excellent, and wear resistance and fracture strength It becomes easy to obtain a vulcanized product of a conjugated diene polymer satisfying the above. Here, the amount of bonded aromatic vinyl can be measured by ultraviolet absorption of a phenyl group, and the amount of bonded conjugated diene can also be obtained from this. Specifically, the sample is dissolved in chloroform to obtain a measurement sample, and the amount of bound styrene (% by mass) can be measured by absorption at UV254 nm by the phenyl group of styrene (for example, a spectrophotometer “UV-2450 manufactured by Shimadzu Corporation”). ").

  The vinyl bond amount (1,2- or 3,4-bond) in the conjugated diene bond unit in the conjugated diene polymer is not particularly limited, but is preferably 10 mol% to 75 mol%, preferably 13 mol%. More preferably, it is 65 mol% or less. When the amount of vinyl bonds is in the above range, when the obtained conjugated diene polymer is used, for example, as a tire tread material, the balance between low hysteresis loss and wet skid resistance is further improved, and wear resistance and fracture strength are also improved. A satisfactory vulcanized product of a conjugated diene polymer can be obtained. Here, when the conjugated diene polymer is a copolymer of butadiene and styrene, the vinyl bond in the butadiene bond unit is obtained by the method of Hampton (RR Hampton, Analytical Chemistry, 21, 923 (1949)). The amount (1,2-bond amount) can be determined.

  When the conjugated diene polymer is a copolymer, it may be a random copolymer or a block copolymer.

  Examples of the random copolymer include a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer. The composition distribution of each monomer in the copolymer chain is not particularly limited, and examples thereof include a completely random copolymer close to a statistical random composition and a tapered (gradient) random copolymer having a gradient in composition distribution. . The bonding mode of the conjugated diene polymer, that is, the composition such as 1,4-bond or 1,2-bond may be uniform or different depending on the molecular chain.

  Examples of the block copolymer include a 2 type block copolymer composed of 2 blocks, a 3 type block copolymer composed of 3 blocks, and a 4 type block copolymer composed of 4 blocks. Here, a block composed of an aromatic vinyl monomer such as styrene is represented by S, and a block composed of a conjugated diene monomer such as butadiene and isoprene and / or a block composed of a copolymer of an aromatic vinyl monomer and a conjugated diene monomer is represented by B. When expressed, it is expressed by a formula such as an S-B2 type block copolymer, a S-B-S3 type block copolymer, and a S-B-S-B4 type block copolymer.

  In the above equation, the boundaries of each block need not be clearly distinguished. For example, when the block B is a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the aromatic vinyl monomer in the block B may be uniformly distributed or may be distributed in a tapered shape. Further, a plurality of portions in which the aromatic vinyl monomer is uniformly distributed and / or a portion in which the block is distributed in a tapered shape may coexist in the block B. A plurality of segments having different aromatic vinyl monomer contents may coexist in the block B. When a plurality of blocks S and blocks B are present in the copolymer, the structures such as molecular weight and composition thereof may be the same or different.

  The weight average molecular weight (Mw) of the conjugated diene polymer is preferably 100,000 or more and 2,000,000 or less, more preferably 200,000 or more and 1,000,000 or less, and further preferably 500,000 or more and 1,000,000 or less in consideration of processability and physical properties.

  The molecular weight distribution (Mw / Mn) of the conjugated diene polymer is preferably 1.02 or more and 6.0 or less, more preferably 1.05 or more and 5.0 or less, and further preferably 1.07 or more and 4. 0 or less. When the molecular weight distribution is 6.0 or less, low hysteresis loss tends to be good. Moreover, when the molecular weight distribution is 1.02 or more, the mixing property and workability of the silica compound are improved. The molecular weight distribution is a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). The weight average molecular weight and the number average molecular weight are determined from gel permeation chromatography (hereinafter referred to as “GPC”) as a calibration formula using a standard polystyrene sample, and are described in detail in the following examples. It can measure according to.

<Polymerization initiator>
In the present embodiment, the polymerization initiator for polymerizing the conjugated diene monomer or polymerizing the conjugated diene monomer and the aromatic vinyl monomer is an organic alkali metal and / or an organic alkaline earth from the viewpoint of stability and handleability. For example, organoaluminum, organomagnesium, organolithium, organosodium, and organopotassium are preferred, and organolithium is particularly preferred from the viewpoint of polymerization efficiency. Examples of the organic lithium used as a polymerization initiator include low molecular weight compounds and solubilized oligomeric organic lithium. From the viewpoint of the bonding mode between an organic group and lithium, a compound having a carbon-lithium bond, a nitrogen-lithium bond. And a compound having a tin-lithium bond.

  Examples of the organic lithium having a carbon-lithium bond include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.

  Examples of the organic lithium having a nitrogen-lithium bond include lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium di-n-hexylamide, lithium diisopropylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, and lithium. Examples include heptamethylene imide and lithium morpholide.

  As the organic lithium, polymerization can be performed using polyfunctional organic lithium instead of the above monoorganolithium, or using monoorganolithium and polyfunctional organic lithium in combination. Organolithium may be used alone or in combination of two or more.

  Examples of the polyfunctional organic lithium include 1,4-dilithiobutane, a reaction product of sec-butyllithium and diisopropenylbenzene, 1,3,5-trilithiobenzene, n-butyllithium, 1,3-butadiene, and divinylbenzene. And a reaction product of n-butyllithium and a polyacetylene compound. Organolithium disclosed in US Pat. No. 5,708,092, British Patent 2,241,239, US Pat. No. 5,527,753 and the like can also be used. As the organic lithium, n-butyllithium and sec-butyllithium are preferable from the viewpoints of industrial availability and ease of control of the polymerization reaction.

  When organolithium is used for polymerization, in order to improve the handleability and dispersibility in the polymerization solution, a solution previously diluted with the hydrocarbon solvent described above may be used.

  The concentration when the organic lithium is diluted in the hydrocarbon solvent is preferably in the range of 0.01% by mass or more and 1% by mass or less, more preferably from the viewpoint of polymerization initiation efficiency and uniform mixing with the monomer. It is 0.1 mass% or more and 0.8 mass% or less.

<Polar compound>
In the polymerization step of polymerizing the conjugated diene monomer or polymerizing the conjugated diene monomer and the aromatic vinyl monomer, a polar compound may be added to the reaction system. The polar compound can be used for randomly copolymerizing an aromatic vinyl monomer with a conjugated diene monomer, and can also be used as a vinylating agent for controlling the microstructure of the conjugated diene moiety. It is also effective in improving the polymerization rate.

  The polar compound is not particularly limited, and examples thereof include tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis (2-oxolanyl) propane. Ethers of: tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, and sodium Examples thereof include alkali metal alkoxide compounds such as amylate; phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

  The usage-amount of a polar compound is not specifically limited, It can select according to the objective etc. It is preferable that it is 0.01 mol or more and 100 mol or less with respect to 1 mol of polymerization initiators. Such a polar compound (vinylating agent) can be used in an appropriate amount according to the desired vinyl bond amount as a regulator of the microstructure of the polymer conjugated diene moiety.

  Many polar compounds simultaneously have an effective randomizing effect in the copolymerization of a conjugated diene monomer and an aromatic vinyl monomer, and can be used as an adjustment of the distribution of the aromatic vinyl monomer and an adjuster of the styrene block amount. As a method for randomizing the conjugated diene monomer and the aromatic vinyl monomer, for example, as described in JP-A No. 59-140221, a part of 1,3-butadiene is intermittently produced during the copolymerization. You may use the method of adding to.

<Reaction temperature>
Although the reaction temperature in a superposition | polymerization process will not be specifically limited if superposition | polymerization advances, It is preferable that it is 0 to 140 degreeC. A reaction temperature of 0 ° C. or higher is preferable from the viewpoint of productivity, and a reaction temperature of 140 ° C. or lower is preferable because gel formation can be suppressed. The lower limit of the reaction temperature in the polymerization step is more preferably 30 ° C. or higher because the polymerization amount can be increased efficiently, more preferably 50 ° C. or higher, and even more preferably 70 ° C. or higher. Moreover, since the deactivation during superposition | polymerization can be suppressed as the upper limit of reaction temperature is 120 degrees C or less, it is more preferable and it is further more preferable that it is 100 degrees C or less.

<Reaction time>
The reaction time in the polymerization step is preferably 5 to 120 minutes. By setting it to 5 minutes or more, a polymer having a high molecular weight can be synthesized, and by setting it to 120 minutes or less, gel formation can be suppressed. Here, the reaction time is the time from mixing the monomer and the polymerization initiator to stopping the polymerization reaction. When employing continuous polymerization, the reaction time is calculated from the following equation as the average reaction time.
Average reaction time (minutes) = reaction tank volume (L) / total raw material charge (L / minute)

  The polymerization process may be continuous polymerization or batch polymerization, but continuous polymerization is preferred from the viewpoint of production efficiency.

  After obtaining the conjugated diene polymer by the method as described above, the conjugated diene polymer may be modified by reacting a compound having an epoxy group and / or an alkoxysilyl group at the active terminal of the conjugated diene polymer. .

  Examples of the compound having an epoxy group include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether and glycerin triglycidyl ether, and aromatics having two or more phenol groups such as 4,4′-diglycidyl-bisphenol A. Polyglycidyl ethers of group compounds; 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxy compounds such as polyepoxidized liquid polybutadiene; 4,4′-diglycidyl-diphenylmethylamine, and 4 , 4′-diglycidyl-dibenzylmethylamine-containing tertiary amines; diglycidyl aniline, diglycidyl orthotoluidine, tetraglycidyl meta-xylene diamine, tetraglycidyl aminodiphenylmethane, tetraglycyl Jill -p- phenylenediamine, diglycidyl aminomethyl cyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane, and diglycidylamino compounds such as tetraglycidyl-1,3-bis-aminomethyl cyclopentane, and the like. Of these, polyfunctional compounds having a diglycidylamino group are preferred. The number of epoxy groups in the molecule of the polyfunctional compound having a diglycidylamino group is 2 or more, preferably 3 or more, more preferably 4 or more.

<Others>
After the polymerization, a deactivator, a neutralizing agent, etc. may be added to the reaction solution as necessary. The quenching agent is not particularly limited, and examples thereof include water; alcohols such as methanol, ethanol, and isopropanol. The neutralizing agent is not particularly limited, and examples thereof include carboxylic acids such as stearic acid, oleic acid, and versatic acid, aqueous solutions of inorganic acids, and carbon dioxide gas.

  Furthermore, it is preferable to add a stabilizer for rubber to the obtained conjugated diene polymer from the viewpoint of preventing the formation of gel after polymerization and improving the stability during processing. The stabilizer for rubber is not particularly limited, and a known stabilizer can be used. For example, 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3- (4′- Antioxidants such as hydroxy-3 ′, 5′-di-tert-butylphenol) propinate and 2-methyl-4,6-bis [(octylthio) methyl] phenol are preferred.

  The devolatilization step for removing the solvent from the polymerization solution is not particularly limited, and examples thereof include a devolatilization method while transporting the polymer solution with a rotating screw such as a steam stripping method or a twin screw extruder or a kneader.

  Next, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples unless it exceeds the gist. Measurement methods and evaluation methods in Examples and Comparative Examples are as follows.

(1) Measurement of weight average molecular weight and molecular weight distribution The chromatogram of a sample and standard polystyrene was measured using GPC using three columns connected with polystyrene gel as a filler (guard column: Tosoh Corporation). (Trade name: TSKguardcumn HHR-H, column: TSKgel G6000HHR, TSKgel G5000HHR, TSKgel G4000HHR manufactured by Tosoh Corporation). A calibration curve was prepared from the measurement results of standard polystyrene, and thereby the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were calculated. Tetrahydrofuran (THF) was used as the eluent. A 10 mg sample of the conjugated diene polymer was dissolved in 20 mL of THF, and this was injected into a 200 μL column and measured. The measurement was performed using an HLC8020 (detector; RI) manufactured by Tosoh Corporation under conditions of an oven temperature of 40 ° C. and a THF flow rate of 1.0 mL / min.

(2) Measurement of amount of residual solvent in conjugated diene polymer 0.1 g of a conjugated diene polymer sample was sealed in a 20 mL headspace bottle, and 30 minutes at 150 ° C. with a headspace sampler (G1888, manufactured by Agilent Technology). After heating, 1 mL of the heated gas phase portion was injected into a gas chromatograph (6890N manufactured by Agilent Technology). The column was Ultra 1 (0.2 mmφ × 25 m, df = 0.33 μm, manufactured by Agilent Technology), the inlet temperature was 250 ° C., the column temperature was maintained at 40 ° C. for 3 minutes, 10 ° C./minute after sample injection. When the temperature reached 100 ° C., the rate of temperature increase was changed to 20 ° C./min, and when the temperature reached 300 ° C., the temperature was maintained for 10 minutes. Peaks corresponding to n-hexane, 2-methylpentane, 3-methylpentane, cyclohexane, and methylcyclopentane are selected from the peaks of the obtained chromatogram, and the peak area created using the above pure reagent in advance The amount of each component generated per 1 g of the sample was determined by quantifying the solvent component from a calibration curve representing the concentration relationship, and the total value was taken as the residual solvent amount.

(3) Measurement of gel content 3 g of the polymer from which the solvent was removed by devolatilization was completely dissolved in 100 g of toluene and filtered through 100 mesh filter paper. The initial weight of the filter paper was α1 [g], the weight when the filtered filter paper was dried was α2 [g], and the gel content (mass%) was determined from the following calculation formula.
Gel content (% by mass) = 100 × (α2−α1) / 3

(Example 1)
After mixing 1,3-butadiene at 22 g / min, styrene at 12 g / min and acyclic aliphatic C6 component (a) at 150 g / min, the mixture was continuously fed to the bottom of a 10 L polymerization tank. The composition of the acyclic aliphatic C6 component (a) was 70% by mass of n-hexane, 21% by mass of 2-methylpentane, and 9% by mass of 3-methylpentane. From the bottom of this polymerization tank, further, 0.038 g / min of 2,2-bis (2-oxolanyl) propane as a polar substance, 0.013 g / min of n-butyllithium as a polymerization initiator, cycloaliphatic C6 As components, cyclohexane was supplied at a rate of 12 g / min and methylcyclopentane was supplied at a rate of 12 g / min, and the continuous polymerization reaction was continued so that the internal temperature of the polymerization tank was 90 ° C. The average reaction time for continuous polymerization was 38 minutes. The solvent composition in the polymerization tank was 86% by mass of the acyclic aliphatic C6 component (a), 7% by mass of cyclohexane, and 7% by mass of methylcyclopentane. The polymerization tank was filled with the polymerization solution, and the polymerization solution extruded from the top of the polymerization tank was supplied through a pipe to the bottom of the 10 L modified reaction tank. The temperature of the denaturing reactor is maintained at 85 ° C., and tetraglycidyl-1,3-bisaminomethylcyclopentane is added as a denaturing agent at a rate of 0.42 mmol / min from the bottom of the denaturing reactor, and the inside of the denaturing reactor is stirred. The modification reaction was carried out with stirring and mixing. After adding 0.048 g / min (n-hexane solution) to an antioxidant (BHT) to the copolymer solution extruded from the top of the modification reaction vessel, the jacket temperature is 180 ° C. and the inside of the apparatus is 100 mmHg. The conjugated diene copolymer (P1) was obtained by supplying to a kneader having a biaxial rotating screw and performing solvent devolatilization. As a result of analyzing (P1), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was less than 0.1% by mass, and the residual solvent amount was 0.015% by mass.

(Example 2)
The solvent supplied to the polymerization tank was the same as that of Example 1 except that the acyclic aliphatic C6 component (a) was 164 g / min, cyclohexane was 5 g / min, and methylcyclopentane was 5 g / min. The solvent composition in the polymerization tank was 94% by mass of the acyclic aliphatic C6 component (a), 3% by mass of cyclohexane, and 3% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P2), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was 0.7% by mass, and the residual solvent amount was 0.005% by mass. there were.

Example 3
The solvent supplied to the polymerization tank was the same as in Example 1 except that the acyclic aliphatic C6 component (a) was 132 g / min, cyclohexane was 21 g / min, and methylcyclopentane was 21 g / min. The solvent composition in the polymerization tank was 77% by mass of the acyclic aliphatic C6 component (a), 12% by mass of cyclohexane, and 12% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P3), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was less than 0.1% by mass, and the residual solvent amount was 0.083% by mass. Met.

(Example 4)
The solvent supplied to the polymerization tank was the same as that of Example 1, except that the acyclic aliphatic C6 component (a) was 127 g / min, cyclohexane was 12 g / min, and methylcyclopentane was 35 g / min. The solvent composition in the polymerization tank was 73% by mass of the acyclic aliphatic C6 component (a), 7% by mass of cyclohexane, and 20% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P4), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was less than 0.1% by mass, and the residual solvent amount was 0.032% by mass. Met.

(Example 5)
The solvent supplied to the polymerization tank was the same as that of Example 1 except that the acyclic aliphatic C6 component (a) was 127 g / min, cyclohexane was 42 g / min, and methylcyclopentane was 5 g / min. The solvent composition in the polymerization tank was 73% by mass of the acyclic aliphatic C6 component (a), 24% by mass of cyclohexane, and 3% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P5), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was less than 0.1% by mass, and the residual solvent amount was 0.042% by mass. Met.

(Example 6)
The solvent supplied to the polymerization tank was the same as in Example 1 except that the acyclic aliphatic C6 component (a) was 171 g / min, cyclohexane was 1.5 g / min, and methylcyclopentane was 1.5 g / min. went. The solvent composition in the polymerization tank was 98% by mass of the acyclic aliphatic C6 component (a), 1% by mass of cyclohexane, and 1% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P6), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was 0.3% by mass, and the residual solvent amount was 0.092% by mass. there were.

(Example 7)
The solvent supplied to the polymerization tank was the same as that of Example 1 except that the acyclic aliphatic C6 component (a) was 148 g / min, cyclohexane was 3 g / min, and methylcyclopentane was 23 g / min. The solvent composition in the polymerization tank was 85% by mass of the acyclic aliphatic C6 component (a), 2% by mass of cyclohexane, and 13% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P7), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was 0.5% by mass, and the residual solvent amount was 0.095% by mass. there were.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that the solvent supplied to the polymerization tank was 112 g / min for the acyclic aliphatic C6 component (a), 31 g / min for cyclohexane, and 31 g / min for methylcyclopentane. The solvent composition in the polymerization tank was 64% by mass of the acyclic aliphatic C6 component (a), 18% by mass of cyclohexane, and 18% by mass of methylcyclopentane. As a result of analyzing the obtained conjugated diene copolymer (P8), the weight average molecular weight was 980,000, the molecular weight distribution was 2.1, the gel content was less than 0.1% by mass, and the residual solvent amount was 0.22% by mass. Met.

(Comparative Example 2)
The same procedure as in Example 1 was carried out except that a solvent containing no cycloaliphatic C6 component (that is, a solvent composed only of the acyclic aliphatic C6 component (a)) was supplied to the polymerization tank at 174 g / min. It was. As a result of analyzing the obtained conjugated diene copolymer (P9), the weight average molecular weight was 920,000, the molecular weight distribution was 2.2, the gel content was 1.2% by mass, and the residual solvent amount was 0.02% by mass. there were.

  The conditions and results of the above examples and comparative examples are summarized in Table 1 below.

Claims (3)

Production of a conjugated diene polymer comprising a step of polymerizing a conjugated diene monomer or polymerizing a conjugated diene monomer and an aromatic vinyl monomer using an organic alkali metal and / or organic alkaline earth metal as a polymerization initiator in a hydrocarbon solvent A method,
It said hydrocarbon solvent is 1 to 30 wt% observed including the mass of the total hydrocarbon solvent cycloaliphatic C6 component comprising 6 carbon cyclic aliphatic hydrocarbon carbon,
The cycloaliphatic C6 component contains cyclohexane and methylcyclopentane;
A method for producing a conjugated diene polymer.   The said hydrocarbon solvent contains 70-99 mass% of the acyclic aliphatic C6 component which consists of a C6 acyclic aliphatic hydrocarbon with respect to the mass of all the hydrocarbon solvents. A method for producing a conjugated diene polymer. The manufacturing method of the conjugated diene polymer of Claim 1 or 2 in which the said cycloaliphatic C6 component contains 5-80 mass% methylcyclopentane with respect to the total mass of a cycloaliphatic C6 component.