JP7177726B2 - Method for producing polybutadiene mixture - Google Patents

Description

The present invention relates to a method for producing polybutadiene mixtures . More particularly, it relates to a method of making polybutadiene mixtures containing 1,2-polybutadiene and 1,4-polybutadiene.

A crystalline 1,2-polybutadiene resin is produced by syndiotactic-1,2 polymerization of 1,3-butadiene in an inert solvent such as a hydrocarbon in the presence of a catalyst. Such crystalline 1,2-polybutadiene resins are used in various applications such as shoe sole materials and medical moldings. Further, in resin materials containing 1,2-polybutadiene resin having crystallinity, attempts have been made to improve various properties required according to each application (see, for example, Patent Documents 1 and 2).

In Patent Document 1, by blending a 1,2-polybutadiene resin having crystallinity and a specific high-molecular silicone compound in a specific ratio, molding appearance is excellent and flexibility, abrasion resistance, and mechanical strength properties are obtained. It is disclosed to obtain a thermoplastic elastomer excellent in such as. Further, in Patent Document 2, by blending a 1,2-polybutadiene resin having crystallinity and a specific styrene-conjugated diene compound block copolymer in a specific ratio, adhesion to a polar resin is improved. is disclosed.

JP 2004-217845 A JP-A-2007-23062

In recent years, as consumer awareness of resource saving, energy saving, and safety has increased, resin materials with excellent tensile strength, elongation, and toughness (tensile product) have been developed in order to improve the durability and wear resistance of products. development is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a polybutadiene mixture capable of obtaining a polybutadiene resin excellent in tensile strength, elongation and toughness.

In order to solve the above problems, the present invention provides the following polybutadiene mixture, method for producing the same, and molded article.

[1] Including a step Y of polymerizing 1,3-butadiene in the presence of 1,2-polybutadiene and a lanthanoid catalyst, wherein the polymerization of 1,2-polybutadiene and 1,3-butadiene during the polymerization of step Y A method for producing a polybutadiene mixture, wherein the mass ratio is 1,2-polybutadiene/1,3-butadiene=95/5 to 50/50.
[2] A polybutadiene mixture containing 1,2-polybutadiene and 1,4-polybutadiene, obtained by polymerizing 1,3-butadiene in the presence of 1,2-polybutadiene and a lanthanide catalyst. and a polybutadiene mixture, wherein the mass ratio of 1,2-polybutadiene and 1,3-butadiene in the polymerization is 1,2-polybutadiene/1,3-butadiene=95/5 to 50/50.
[3] A molded article formed using the polybutadiene mixture obtained by the production method of [1] above or the polybutadiene mixture of [2] above.

According to the polybutadiene mixture and the method for producing the same of the present invention, a polybutadiene resin material excellent in tensile strength, elongation and toughness can be obtained.

Matters relating to aspects of the present disclosure are described in detail below. In this specification, the numerical range described using "-" means that the numerical values described before and after "-" are included as the lower limit and the upper limit.

The polybutadiene mixtures of the present disclosure contain 1,2-polybutadiene and 1,4-polybutadiene. The polybutadiene rubber mixture is produced by a method including a step of polymerizing 1,3-butadiene in the presence of 1,2-polybutadiene and a lanthanide catalyst (hereinafter referred to as "step Y"). The polybutadiene mixture of the present disclosure is preferably produced by a process comprising step Y and further step X of obtaining 1,2-polybutadiene. Each step will be described in detail below.

<Step X (1, 2 polymerization step)>
Step X is a step of producing 1,2-polybutadiene, which is a matrix component of a polybutadiene mixture, by polymerizing 1,3-butadiene in the presence of a cobalt-based catalyst. This step X includes a step of preparing a mixture of 1,3-butadiene and an organic solvent, a step of polymerizing 1,3-butadiene (more specifically, 1,2 polymerization) in the presence of a cobalt-based catalyst, and terminating the polymerization reaction. The 1,2-polybutadiene obtained by the polymerization reaction in step X is hereinafter also referred to as "1,2-polybutadiene (A)".

(Preparation process)
The organic solvent used in this step is a solvent containing a hydrocarbon or a halogenated hydrocarbon as a main component. Specific examples of hydrocarbons include saturated aliphatic hydrocarbons having 4 to 10 carbon atoms such as butane, pentane, hexane and heptane; saturated alicyclic hydrocarbons having 6 to 20 carbon atoms such as cyclopentane and cyclohexane; monoolefins such as butene and 2-butene; and aromatic hydrocarbons such as benzene, toluene and xylene. Specific examples of halogenated hydrocarbons include methylene chloride, chloroform, carbon tetrachloride, trichlorethylene, perchlorethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene and chlorotoluene. Among these, hydrocarbons can be preferably used as the organic solvent.

In the mixture of 1,3-butadiene and organic solvent, the amount of 1,3-butadiene with respect to the total amount of 1,3-butadiene and organic solvent is preferably 3 to 80 mass%, preferably 15 to 30 mass%. is more preferable. The temperature at which the mixture of 1,3-butadiene and organic solvent is prepared is preferably 10 to 50°C, more preferably 30 to 40°C.

(1,2 polymerization step)
In this step, a mixture of 1,3-butadiene and an organic solvent obtained in the above preparation step is used, and 1,3-butadiene is dissolved in an organic solvent mainly composed of a hydrocarbon or a halogenated hydrocarbon in the presence of a cobalt-based catalyst. 3-Butadiene is 1,2-polymerized. Thereby, 1,2-syndiotactic polybutadiene can be produced as 1,2-polybutadiene (A).

The cobalt-based catalysts used contain cobalt compounds. The cobalt compound is preferably a cobalt salt, and specifically, cobalt halide salts such as cobalt chloride, cobalt bromide, and cobalt iodide; organic acid cobalt salts such as cobalt octylate, cobalt versatate, and cobalt naphthenate. , and so on. Among these, it is preferable to use an organic acid cobalt salt as the cobalt compound because it does not contain a halogen atom.

The ratio of the cobalt compound used is such that the molar ratio of 1,3-butadiene (1,3-butadiene/Co) to the cobalt atoms of the cobalt compound is 15,000 to 150,000. is preferred, and an amount of 10,000 to 100,000 is more preferred. A 1,3-butadiene/Co (molar ratio) of 5,000 or more is preferable in that the molecular weight of 1,2-polybutadiene (A) can be prevented from becoming too low. In addition, it is preferable to set the 1,3-butadiene/Co (molar ratio) to 150,000 or less in that a decrease in polymerization activity can be suppressed.

The cobalt-based catalyst used in step X preferably further contains a phosphine compound and an organoaluminum compound together with the cobalt compound. The phosphine compound is a phosphine compound having one branched aliphatic hydrocarbon group having 3 or more carbon atoms or an alicyclic hydrocarbon group having 5 or more carbon atoms and two aromatic hydrocarbon groups. is preferred. The branched aliphatic hydrocarbon group having 3 or more carbon atoms is preferably a branched alkyl group having 3 to 10 carbon atoms. The alicyclic hydrocarbon group having 5 or more carbon atoms is preferably a substituted or unsubstituted cycloalkyl group having 5 to 10 carbon atoms. Aromatic hydrocarbon groups are preferably phenyl groups.

Preferred specific examples of the phosphine compound include diphenylcyclohexylphosphine, diphenylisopropylphosphine, diphenylisobutylphosphine, diphenylt-butylphosphine, diphenylcyclopentylphosphine, diphenyl(4-methylcyclohexyl)phosphine, diphenylcycloheptylphosphine, diphenylcyclooctylphosphine, and the like. is mentioned. In addition, as a phosphine compound, it can be used individually by 1 type or in combination of 2 or more types. The mixing ratio of the phosphine compound is preferably 1 to 5 mol, more preferably 1.5 to 4 mol, per 1 mol of the cobalt compound.

Examples of organoaluminum compounds include aluminoxanes (methylaluminoxane, etc.) and compounds obtained by contacting trialkylaluminum with water (hereinafter referred to as "aluminum hydride compounds"). The aluminoxane may be one synthesized in advance or one synthesized in the polymerization system. Regarding the aluminum hydride compound, the method of contacting the trialkylaluminum with water is to contact the inert organic solvent solution of the trialkylaluminum with water in any of the states of vapor, liquid, and solid (ice). good. Also, contact may be made in a dissolved state, dispersed state, or emulsified state in an inert organic solvent, or in a gaseous state or mist state existing in an inert gas.

In the cobalt-based catalyst, the proportion of the organoaluminum compound used is such that the molar ratio of 1,3-butadiene to the aluminum atoms of the organoaluminum compound (1,3-butadiene/Al) is 500 to 4,000. It is preferable to set the amount to 800 to 2,000. When the 1,3-butadiene/Al (molar ratio) is 500 or more, the reaction proceeds sufficiently.

The reaction temperature in the 1,2 polymerization is usually -20°C to 80°C, preferably 30°C to 70°C. The reaction time is preferably 5 minutes to 6 hours, more preferably 10 to 3 hours. The polymerization reaction may be of a batch system or a continuous system. The concentration of 1,3-butadiene in the reaction solution is usually 5-80% by mass, preferably 8-25% by mass. In addition, in order to prevent deactivation of the catalyst and the polymer, measures may be taken to suppress contamination of a deactivating compound such as oxygen, water, or carbon dioxide gas into the polymerization system.

(Suspension process)
In step X, after the syndiotactic-1,2 polymerization reaction reaches the desired reaction conversion, it is preferred to terminate the 1,2 polymerization reaction by adding an organoaluminum compound to the polymerization system.

Examples of organoaluminum compounds used for terminating the 1,2 polymerization reaction include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-t- alkylaluminum compounds such as butylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum;
diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, diisohexylaluminum hydride, dioctylaluminum hydride, diisooctyl hydride and aluminum hydride compounds such as aluminum. Among these, the organoaluminum compound used for terminating the 1,2 polymerization reaction is at least one selected from the group consisting of diisobutylaluminum hydride, triethylaluminum, triisobutylaluminum, and diethylaluminum hydride. is preferred. In addition, as an organoaluminum compound, it can be used individually or in combination of 2 or more types.

When terminating the 1,2 polymerization reaction, the ratio of the organoaluminum compound used is preferably 1 to 20 mol, more preferably 5 to 15 mol, per 1 mol of the cobalt compound used in the 1,2 polymerization reaction. . By setting the proportion of the organoaluminum compound used within the above range, the molecular weight of 1,2-polybutadiene (A) does not become too high, or the molecular weight of 1,4-polybutadiene obtained in step Y does not become too low, preferred. The temperature at which the polymerization termination reaction is carried out is usually -20°C to 80°C, preferably 30°C to 70°C.

According to step X, 1,2-syndiotactic polybutadiene can be produced as 1,2-polybutadiene (A). The melting point of the obtained 1,2-polybutadiene (A) is preferably 60° C. or higher, more preferably 100° C. or higher, and even more preferably 120° C. or higher. Setting the melting point of the 1,2-polybutadiene (A) to 60° C. or higher is preferable in that the tensile strength of the elastic body (molded article) obtained using the polybutadiene mixture can be sufficiently increased.

The polystyrene equivalent weight average molecular weight (Mw) of 1,2-polybutadiene (A) by gel permeation chromatography (GPC) is preferably 50,000 or more, more preferably 70,000 or more, 100,000 or more is particularly preferred. Further, the weight average molecular weight (Mw) of 1,2-polybutadiene (A) is preferably 600,000 or less, more preferably 500,000 or less, and particularly preferably 450,000 or less. . When the weight average molecular weight of the 1,2-polybutadiene (A) is less than 50,000, the wear resistance of the molded article obtained using the polybutadiene mixture tends to decrease. tend to decline.

The content of 1,2-vinyl bonds in 1,2-polybutadiene (A) is preferably 90% or more, more preferably 95% or more. A 1,2-vinyl bond content of 90% or more is preferable because the abrasion resistance of the molded article obtained using the polybutadiene mixture can be improved.

<Step Y (cis-1,4 polymerization step)>
In step Y, 1,4-polybutadiene is produced by polymerizing 1,3-butadiene (cis-1,4 polymerization) in the presence of 1,2-polybutadiene and a lanthanoid catalyst. In this step, the 1,2-polybutadiene (A) produced in step X is preferably used as the 1,2-polybutadiene. At that time, it is preferable to add a lanthanoid catalyst to the reaction mixture obtained in the above step X to polymerize 1,3-butadiene, in order to simplify the production process. The 1,4-polybutadiene obtained by the polymerization reaction in step Y is hereinafter also referred to as "1,4-polybutadiene (B)".

In the cis-1,4 polymerization, the ratio (mass ratio) of 1,2-polybutadiene and 1,3-butadiene is 1,2-polybutadiene/1,3-butadiene=95/5 to 50/50. If the ratio of 1,2-polybutadiene to 1,3-butadiene is too high, the content of 1,4-polybutadiene in the polybutadiene mixture will be too low, and a sufficient effect of improving tensile strength cannot be obtained. On the other hand, if the ratio of 1,2-polybutadiene to 1,3-butadiene is too low, the content of 1,2-polybutadiene in the polybutadiene mixture is too low, and sufficient thermoplasticity cannot be obtained. The ratio of 1,2-polybutadiene and 1,3-butadiene is preferably 95/5 to 60/40, more preferably 90/10 to 60/40, still more preferably 90/10 to 65/ 35.

The lanthanoid-based catalyst used in step Y contains a lanthanide compound. A lanthanide compound is a compound having at least one element belonging to the lanthanoids. The lanthanoid compound may be a reaction product between a lanthanoid-containing compound and a Lewis base. The lanthanoid contained in the lanthanoid compound is preferably at least one selected from the group consisting of neodymium, praseodymium, cerium, lanthanum, gadolinium and samarium, and neodymium is particularly preferred. Specific examples of the lanthanoid compounds include lanthanoid carboxylates, alkoxides, β-diketone complexes, phosphates, and phosphites.

Specific examples of ^lanthanide carboxylates include compounds represented by the _{formula (} ¹ ); is a monovalent hydrocarbon group). In the above formula (1), R ¹ is preferably a saturated or unsaturated monovalent chain hydrocarbon group, preferably a linear, branched or cyclic alkyl group. The carbonyl group in the formula (1) is bonded to a primary, secondary or tertiary carbon atom of R ¹ . M is preferably neodymium, praseodymium, cerium, lanthanum, gadolinium or samarium, more preferably neodymium.
Specific examples of the compound represented by the above formula (1) include octanoic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, benzoic acid, naphthenic acid, trade name "Versatic acid" (manufactured by Shell Chemical Co., carboxyl carboxylic acids in which the group is attached to a tertiary carbon atom). Among these, the compound represented by the above formula (1) is preferably a salt of versatic acid, 2-ethylhexanoic acid or naphthenic acid.

Specific examples of lanthanide alkoxides include compounds represented by formula (2); (R ² O) ₃ M (where M is a lanthanoid and R ² is a monovalent hydrocarbon group ). In formula (2) above, R ² includes a monovalent chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and the like. R ² is preferably a monovalent aromatic hydrocarbon group. Specific examples of the group “R ² O—” in formula (2) above include a 2-ethyl-hexylalkoxy group, an oleylalkoxy group, a stearylalkoxy group, a phenoxy group and a benzylalkoxy group. Among these, the group “R ² O—” is preferably a 2-ethyl-hexylalkoxy group or a benzylalkoxy group. For the description and preferred examples of M, the description of formula (1) above applies.

Specific examples of β-diketone complexes of lanthanoids include acetylacetone complexes, benzoylacetone complexes, propionitrileacetone complexes, valerylacetone complexes, and ethylacetylacetone complexes. Of these, an acetylacetone complex or an ethylacetylacetone complex is preferred.

Specific examples of lanthanide phosphates or phosphites include bis(2-ethylhexyl) bis(1-methylheptyl) phosphate, bis(p-nonylphenyl) phosphate, bis(polyethylene glycol) phosphate, -p-nonylphenyl), (1-methylheptyl) phosphate (2-ethylhexyl), (2-ethylhexyl) phosphate (p-nonylphenyl), mono-2-ethylhexyl 2-ethylhexylphosphonate, 2-ethylhexylphosphonate mono-p-nonylphenyl acid, bis(2-ethylhexyl)phosphinic acid, bis(1-methylheptyl)phosphinic acid, bis(p-nonylphenyl)phosphinic acid, (1-methylheptyl)(2-ethylhexyl)phosphinic acid , (2-ethylhexyl)(p-nonylphenyl)phosphinic acid and the like. Among these, phosphates or phosphites include bis(2-ethylhexyl) phosphate, bis(1-methylheptyl) phosphate, mono-2-ethylhexyl 2-ethylhexylphosphonate or bis(2-ethylhexyl) ) salts of phosphinic acids are preferred.

Among these, the lanthanoid compound used in step Y is preferably a carboxylate or a phosphate, and more preferably a carboxylate. Among these, neodymium phosphate or neodymium carboxylate is more preferable, and carboxylate such as neodymium versatate or neodymium 2-ethylhexanoate is particularly preferable.

In order to solubilize the lanthanoid compound in a solvent or store it stably for a long period of time, the lanthanoid compound and the Lewis base may be mixed, or the lanthanoid compound and the Lewis base may be reacted to form a reaction product. preferable. The amount of the Lewis base used is preferably 0 to 30 mol, more preferably 1 to 10 mol, per 1 mol of the lanthanoid contained in the lanthanide compound. Specific examples of Lewis bases include acetylacetone, tetrahydrofuran, pyridine, N,N-dimethylformamide, thiophene, diphenyl ether, triethylamine, organic phosphorus compounds, monohydric or dihydric alcohols, and the like. In addition, in the process Y, as a lanthanoid compound, 1 type can be used individually or in combination of 2 or more types.

The ratio of the lanthanoid compound used in step Y is preferably 0.00001 to 1.0 mmol, more preferably 0.0001 to 0.5 mmol, per 100 g of 1,3-butadiene used in step Y. is more preferred. A use ratio of the lanthanoid compound of 0.00001 millimoles or more is preferable in that the polymerization activity can be sufficiently increased. In addition, by setting the proportion of use to 1.0 millimoles or less, it is possible to prevent the catalyst concentration from becoming too high, which is preferable in that a deashing step is not required.

The lanthanoid-based catalyst used in step Y preferably further contains an organoaluminum compound and a halogen compound together with the lanthanoid compound.

As the organoaluminum compound, it is preferable to use at least one selected from the group consisting of aluminoxanes, alkylaluminum compounds and aluminum hydride compounds. Among these, it is particularly preferable to use at least one compound selected from the group consisting of alkylaluminum compounds and aluminum hydride compounds (hereinafter referred to as "aluminum compound (L)") in combination with aluminoxane.

（式（３）及び式（４）中、Ｒ^３及びＲ^４は、それぞれ独立に炭素数１～２０の１価の炭化水素基であり、ｋ及びｍは、それぞれ独立に２以上の整数である。式（３）中の複数のＲ^３は互いに同じでも異なっていてもよい。ｍが２以上の場合、式（４）中の複数のＲ^４は互いに同じでも異なっていてもよい。） Preferred specific examples of the aluminoxane used in this step include compounds represented by the following formula (3) and compounds represented by the following formula (4). Fine Chemicals, 23, (9) 5 (1994), J.Am.Chem.Soc., 115, 4971 (1993), and J.Am.Che.Soc., 117, 6465 (1995). Aluminoxane aggregates containing

(In formulas (3) and (4), R ³ and R ⁴ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and k and m are each independently an integer of 2 or more. A plurality of R ³ in formula (3) may be the same or different, and when m is 2 or more, a plurality of R ⁴ in formula (4) may be the same or different.)

Examples of R ³ in the above formula (3) and R ⁴ in the above formula (4) include methyl group, ethyl group, propyl group, butyl group, isobutyl group, t-butyl group, hexyl group, isohexyl group and octyl. groups, isooctyl groups, and the like. Among these, a methyl group, an ethyl group, an isobutyl group or a t-butyl group is preferred, and a methyl group is particularly preferred. k and m are preferably integers of 4-100.

Specific examples of aluminoxanes include methylaluminoxane (hereinafter also referred to as "MAO"), ethylaluminoxane, n-propylaluminoxane, n-butylaluminoxane, isobutylaluminoxane, t-butylaluminoxane, hexylaluminoxane, and isohexylaluminoxane. can be done. Among these, MAO is preferred. In addition, as an aluminoxane, 1 type can be used individually or in combination of 2 or more types.

The ratio of the aluminoxane used in the lanthanide-based catalyst is preferably such that the amount of aluminum (Al) in the aluminoxane is 1 to 500 mol per 1 mol of the lanthanoid compound used in the 1,4 polymerization reaction. The amount is more preferably 3 to 250 mol, more preferably 5 to 200 mol. By setting the proportion of the aluminoxane to be used within the above range, it is preferable in terms of suppressing a decrease in catalytic activity and eliminating the need for a step of removing catalyst residues.

Specific examples of the aluminum compound (L) include the alkylaluminum compounds and aluminum hydride compounds exemplified in the explanation of the termination step above. As the aluminum compound (L), one kind may be used alone, or two or more kinds may be used in combination. Among these, the aluminum compound (L) is preferably at least one selected from the group consisting of diisobutylaluminum hydride, triethylaluminum, triisobutylaluminum, and diethylaluminum hydride. In the preparation of the lanthanide-based catalyst, the proportion of the aluminum compound (L) used is such that the total amount of the aluminum compound (L) used is 1 to 700 mol per 1 mol of the lanthanoid compound used in the 1,4 polymerization reaction. preferably 3 to 500 mol.

The halogen compound used as one component of the lanthanide catalyst is preferably a chlorine-containing compound, more preferably at least one selected from the group consisting of silicon chloride compounds and chlorinated hydrocarbon compounds. Silicon chloride compounds used include trimethylsilyl chloride, triethylsilyl chloride, dimethylsilyl dichloride, and the like. Among these, trimethylsilyl chloride can be preferably used as the silicon chloride compound. Specific examples of chlorinated hydrocarbon compounds include methyl chloride, butyl chloride, hexyl chloride, octyl chloride, chloroform, dichloromethane, and benzylidene chloride. Among these, it is preferable to use methyl chloride, chloroform or dichloromethane.

In the preparation of the lanthanide-based catalyst, the ratio of the halogen compound to be used is preferably 0.5 to 3 in terms of the molar ratio of the halogen atoms in the halogen compound (halogen atom/lanthanoid compound) per 1 mol of the lanthanoid compound. It is more preferably 1.0 to 2.5, even more preferably 1.2 to 1.8. A halogen atom/lanthanoid compound molar ratio of 0.5 or more is preferable because the polymerization catalyst activity can be sufficiently increased. In addition, it is preferable that the molar ratio is 3 or less so that the halogen compound can be prevented from becoming a catalyst poison.

The reaction temperature for the 1,4 polymerization in step Y is preferably -30°C to 200°C, more preferably 0°C to 150°C. The form of the polymerization reaction is not particularly limited, and may be carried out using a batch type reactor, or may be carried out continuously using a multi-stage continuous reactor or the like. When the 1,4 polymerization reaction is carried out using a polymerization solvent, the monomer concentration in the solvent is preferably 5 to 50% by mass, more preferably 7 to 35% by mass. From the viewpoint of producing 1,4-polybutadiene and from the viewpoint of preventing 1,4-polybutadiene having an active terminal from being deactivated, a deactivating agent such as oxygen, water or carbon dioxide gas is added to the polymerization system. It is preferable to take measures to prevent contamination by compounds.

The content of 1,4-polybutadiene (B) is preferably 1% by mass or more, more preferably 5% by mass or more, and 8% by mass with respect to the total amount of the polybutadiene mixture obtained by this production method. % or more is more preferable. In addition, the content of 1,4-polybutadiene (B) is preferably 30% by mass or less, more preferably 25% by mass or less, relative to the total amount of the polybutadiene mixture obtained by this production method. A content of 1,4-polybutadiene (B) of 1% by mass or more is preferable in that the tensile strength, elongation and tensile product of the molded article obtained using the polybutadiene mixture can be sufficiently increased. . Further, when the content of the 1,4-polybutadiene (B) is 30% by mass or less, the wear resistance of the molded article obtained using the polybutadiene mixture can be sufficiently increased, which is preferable.

A 1,4-polybutadiene having an active terminal can be obtained by the above 1,4 polymerization reaction. The polystyrene equivalent weight average molecular weight (Mw) of the obtained 1,4-polybutadiene (B) by GPC is preferably 50,000 or more, more preferably 100,000 or more, and 150,000 or more. It is particularly preferred to have Further, the weight average molecular weight (Mw) of 1,4-polybutadiene (B) is preferably 2,000,000 or less, more preferably 1,500,000 or less, and 1,000,000 or less. is particularly preferred. When the weight average molecular weight of 1,4-polybutadiene (B) is less than 50,000, wear resistance tends to decrease, and when it exceeds 2,000,000, workability tends to decrease. .

For 1,4-polybutadiene (B), the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 2.0 to 4.0, more preferably 2.1 to 3.5. more preferred. When the Mw/Mn of the 1,4-polybutadiene rubber is 4.0 or less, it is preferable in that the toughness (tensile product) of the resulting molded product can be improved.

The content of cis-1,4 structure in 1,4-polybutadiene (B) is preferably 89% or more, more preferably 93% or more. When the content of the cis-1,4 structure is 89% or more, the abrasion resistance of the molded article obtained using the polybutadiene mixture can be improved, which is preferable. According to step Y, a mixture of 1,2-syndiotactic polybutadiene as a matrix component and 1,4-polybutadiene (B) is obtained as a polybutadiene mixture.
The content of 1,2-polybutadiene (A) is preferably 70% by mass or more, more preferably 75% by mass or more, relative to the total amount of the polybutadiene mixture obtained by this production method. The content of 1,2-polybutadiene (A) is preferably 99% by mass or less, more preferably 95% by mass or less, and still more preferably 92% by mass or less, relative to the total amount of the polybutadiene mixture. be.

<Other processes>
The production method may further include steps other than the steps X and Y described above.
・ Process Z (denaturation process)
In the above step Y, after the cis-1,4 polymerization reaction reaches the desired reaction conversion rate, an anti-aging agent (for example, 2,4-di-tert-butyl-p-cresol, 4,6 -Bis(octylthiomethyl)-o-cresol, etc.) may be added to the polymerization system, but an alkoxysilane compound may be used to modify the polymerization end of 1,4-polybutadiene (B). By such a modification reaction, the active terminal of 1,4-polybutadiene (B) reacts with the alkoxysilane compound, and 1,4-polybutadiene having a silicon-containing group introduced at the polymerization terminal can be obtained. When the 1,4-polybutadiene contained in the polybutadiene mixture is terminally modified, the polybutadiene mixture is excellent in tensile strength, elongation and tensile product, and is a material for obtaining a vulcanized rubber excellent in fuel efficiency performance. It is suitable as

The alkoxysilane compound (hereinafter also referred to as "alkoxysilane compound (S)") used in the modification step has at least one alkoxysilyl group and can react with the active terminal of 1,4-polybutadiene. A compound is preferred. Among these, the alkoxysilane compound (S) is an alkoxysilane compound having at least one functional group selected from the group consisting of an epoxy group, an isocyanate group, a carbonyl group and a cyano group in that it is highly reactive with the active terminal. is preferably The alkoxysilane compound (S) may be a partial condensate, or a mixture of an alkoxysilane compound and a partial condensate.

The modification reaction is preferably carried out in a solution. As the solution, the solution containing the unreacted monomer obtained in the above step Y can be used as it is. In this case, it is preferable in that the manufacturing process can be simplified. In the modification reaction, the ratio of the alkoxysilane compound (S) used is preferably 0.01 to 200 mol, more preferably 0.1 to 150 mol, per 1 mol of the lanthanoid compound used in step Y above. is more preferable. The modification reaction temperature is preferably the same as the polymerization temperature of 1,4-polybutadiene. The reaction time in the modification reaction is preferably 5 minutes to 5 hours, more preferably 15 minutes to 1 hour. In the production method of the present disclosure, after the completion of the 1,4 polymerization in step Y when the modification reaction is not performed, or after the modification reaction when the modification reaction is performed, if desired, a known anti-aging agent or reaction terminator. can be added in the desolubilization step.

When terminal modification of 1,4-polybutadiene (B) is performed in step Z, in the desolubilization step after the modification reaction, condensation reaction with the residue of the alkoxysilane compound (S) introduced at the active terminal and consumption A compound (hereinafter also referred to as "condensation catalyst") may be further added. As a specific example of the condensation catalyst, a condensation catalyst containing at least one element among elements included in groups 4A, 2B, 3B, 4B and 5B of the periodic table is preferred. By adding a condensation catalyst, the condensation reaction of the residue of the alkoxysilane compound (S) can be promoted more effectively, and 1,4-polybutadiene having excellent workability, low-temperature properties, and abrasion resistance can be obtained. becomes possible.

The polybutadiene mixture of the present disclosure can be obtained by removing the solvent from the solution obtained above and isolating the polymer. Isolation of the polymer can be carried out by known desolvation methods such as steam stripping and drying operations such as heat treatment.

The polybutadiene mixture obtained by this production method has a melting point of 60 to 150° C. for 1,2-syndiotactic polybutadiene, and 1,4-polybutadiene is It is preferably contained in an amount of 5 to 30% by mass with respect to the total amount. The polybutadiene mixture of the present disclosure may be used alone, or optionally blended with other synthetic resins, synthetic rubbers or natural rubbers to form a raw resin or raw rubber, and, if desired, a process oil. After oil extension, commonly used vulcanized rubber compounding agents such as various fillers such as carbon black, vulcanizing agents and vulcanization accelerators are added and vulcanized as a rubber composition to obtain tensile strength. Applications that require strength, elongation and tensile product, specifically, tires, hoses, belts, sponges, footwear materials, sheets, films, tubes, packaging materials, resin modifiers, photosensitive materials, and other It can be used for various industrial products.

The vinyl content (1,2-vinyl bond content) of the polybutadiene mixture obtained by this production method is preferably 90% or more, more preferably 93% or more. A vinyl content of 90% or more is preferable in that the abrasion resistance of the molded article obtained using the polybutadiene mixture can be sufficiently ensured. As used herein, the “vinyl content” is a value measured by ¹ H-NMR.

The polystyrene equivalent weight average molecular weight (Mw) of the polybutadiene mixture measured by GPC is preferably 50,000 or more, more preferably 70,000 or more, and even more preferably 100,000 or more. Also, the weight average molecular weight (Mw) of the polybutadiene mixture is preferably 700,000 or less, more preferably 600,000 or less, and particularly preferably 500,000 or less. The ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in the resulting polybutadiene mixture is preferably 2.0 to 4.0, more preferably 2.1 to 3.5. When the Mw/Mn of the polybutadiene mixture is 4.0 or less, it is preferable in that the fracture properties of the molded article can be improved.

The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. "Parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified. Methods for measuring various physical property values of the polymer are shown below.

[Melting point]: Measured using a differential scanning calorimeter (trade name: X-DSC7000, manufactured by SII Technology Co., Ltd.).
[Weight-average molecular weight and molecular weight distribution]: Using a gel permeation chromatograph (trade name; VISCOTEK GPCmax, manufactured by Malvern), using a differential refractometer as a detector, measured under the following conditions. Calculated.
Column; trade name "GMHHR-H" (manufactured by Tosoh Corporation) 2 pieces, column temperature; 38°C
Mobile phase; tetrahydrofuran, flow rate; 1.0 ml/min sample concentration; 10 mg/20 ml

[Cis-1,4 bond content and vinyl content]: Using an infrared spectrophotometer (trade name; FT/IR-4100 series, manufactured by Jasco), using a ZnSe prism, a wavenumber of 1000 to 600 cm ^-1 was measured. It was measured.
[1,2-polybutadiene content and 1,4-polybutadiene content]: According to the following formulas (1) to (5), the content α [%] of 1,2-syndiotactic polybutadiene in the polybutadiene mixture and 1,4-polybutadiene content β [%] was calculated. Abbreviations in formulas (1) to (5) have the following meanings.
Q1: Amount of 1,3-butadiene (for syndiotactic-1,2 polymerization) input Q2: Amount of 1,2-polybutadiene produced Q3: Amount of unreacted 1,3-butadiene in 1,2 polymerization Q4: 1,3- Input amount of butadiene (for cis-1,4 polymerization) Q5: Amount of 1,4-polybutadiene produced Q2 = Q1 x (reaction conversion rate of syndiotactic-1,2 polymerization) (1)
Q3=Q1-Q2 (2)
Q5 = (Q3 + Q4) x (reaction conversion rate of cis-1,4 polymerization) (3)
Content rate α=(Q2÷(Q2+Q5))×100 (4)
Content rate β = 100-α (5)

1. Production of polybutadiene mixture [Example 1]
1.5 kg of cyclohexane and 300 g of 1,3-butadiene were put into a 3-liter autoclave purged with nitrogen. Separately, a dichloride solution containing 0.12 millimoles of cobalt chloride, a dichloride solution containing 0.24 millimoles of diphenylcyclohexylphosphine, and a toluene solution containing 3.60 millimoles of methylaluminoxane (MAO) were mixed, Catalyst composition A was prepared by reacting at 30° C. for 60 minutes. This catalyst composition A was charged into the autoclave and reacted at 55° C. for 1 hour (syndiotactic-1,2 polymerization) to obtain a polymer solution. The reaction conversion rate of the charged 1,3-butadiene was about 80%. Thereafter, in order to stop the polymerization reaction, a toluene solution containing 1.2 mmol of diisobutylaluminum hydride was charged into the autoclave and stirred for 15 minutes.

In order to measure various physical property values of the polybutadiene resin obtained by the above reaction, 18 g of the polymer solution was withdrawn from the above polymer solution, and 2,6-di-t-butyl-p-cresol was added to the withdrawn polymer solution. was added to stop the polymerization reaction. After that, the solvent was removed by heating on a hot plate. Various physical properties of the obtained polybutadiene resin (1,2-syndiotactic polybutadiene) were measured, and the melting point was 121° C., and the weight average molecular weight (Mw) of 1,2-polybutadiene was 290,000.

followed by a cyclohexane solution containing 8.7 μmoles of neodymium versatate (Nd(ver) ₃ ), a toluene solution containing 0.28 mmoles of MAO, and a toluene solution containing 0.67 mmoles of diisobutylaluminum hydride. and a toluene solution containing 10.6 micromoles of trimethylsilyl chloride (Me ₃ SiCl) and 1.1 mmoles of 1,3-butadiene (equivalent to 1,2-polybutadiene/1,3-butadiene = 80/20). Catalyst composition B was prepared by reacting at 30° C. for 60 minutes. This catalyst composition B was charged into the autoclave and reacted at 70° C. for 1 hour (cis-1,4 polymerization) to obtain a polymer solution containing a polybutadiene mixture. The reaction conversion rate of unreacted 1,3-butadiene in the 1,4 polymerization was about 25%.

Next, in order to measure various physical property values of the polybutadiene mixture obtained by the above reaction, 200 g of the polymer solution was withdrawn from the above polymer solution, and 2,6-di-tert-butyl-p- A toluene solution containing 1.5 g of cresol was added to terminate the polymerization reaction. After that, the solvent was removed by heating on a hot plate to obtain a polybutadiene mixture P1. When various physical property values of the polybutadiene mixture P1 were measured, the 1,2-polybutadiene content was 93.6%, the 1,4-polybutadiene content was 6.4%, the molecular weight distribution (Mw/Mn) was 2.82, The cis-1,4 bond content was 5.0%, the 1,2-vinyl bond content was 95.0%, and the weight average molecular weight (Mw) was 300,000. The 1,2-polybutadiene contained in the polybutadiene mixture P1 had a melting point of 121° C. and a weight average molecular weight (Mw) of 290,000.

[Example 2]
The procedure of Example 1 was repeated except that the polymerization recipe for 1,2 polymerization was as shown in Table 1 below and the polymerization recipe for cis-1,4 polymerization was as shown in Table 2 below. , to obtain a polybutadiene mixture P2. Table 3 below shows the measurement results of the physical properties of the obtained polybutadiene mixture P2. In Table 3, Reference Example 1 shows the measurement results of a commercially available syndiotactic 1,2-polybutadiene resin (trade name “RB840” manufactured by JSR).

Abbreviations in Tables 1 and 2 have the following meanings.
CoCL2: cobalt chloride ( _CoCl2 )
PCH: diphenylcyclohexylphosphine AlBuH: diisobutylaluminum hydride (AlBu ₂ H)
NdVer: neodymium versatate (Nd(ver) ₃ )
MeSiCl: trimethylsilyl chloride ( _Me3SiCl )

2. Evaluation of polybutadiene mixtures [Examples 3 and 4]
The polybutadiene mixtures P1 and P2 obtained in Examples 1 and 2 were evaluated for tensile strength at break (TB), elongation at break (EB) and tensile product. Evaluation was performed according to the following procedures.
First, a polybutadiene mixture was formed into a sheet, and according to JIS K6251:2010, it was punched out with a JIS-3 dumbbell cutter to obtain a test piece for evaluation (dumbbell-shaped test piece). Using a tensile tester (model name "AG-2000", manufactured by Shimadzu Corporation), the above sample piece was pulled at a load rate of 500 mm / min, and tensile strength at break (TB) and elongation at break (EB ) was measured. Also, the tensile product was determined by multiplying the measurement results of tensile strength at break (TB) and elongation at break (EB). The results are shown in Table 4 below. The results were expressed as an index with Comparative Example 1 set to 100.

[Comparative Example 1]
Tensile strength at break ( TB) and elongation at break (EB) were measured, and the tensile product was determined. The results are shown in Table 4 below.
[Comparative Example 2]
To 95 parts of the syndiotactic 1,2-polybutadiene resin used in Comparative Example 1, 5 parts of a commercially available high cis-polybutadiene rubber (trade name "BR740", manufactured by JSR) was blended, and a plastomill was used. A polybutadiene mixture Q1 was obtained by kneading. Using the obtained polybutadiene mixture Q1, the tensile strength at break (TB) and elongation at break (EB) were measured in the same manner as in Examples 1 and 2, and the tensile product was determined. The results are shown in Table 4 below.
[Comparative Example 3]
Kneading was carried out in the same manner as in Comparative Example 2, except that the formulation was changed to that shown in Table 4 below, to obtain a polybutadiene mixture Q2. Using the obtained polybutadiene mixture Q2, the tensile strength at break (TB) and elongation at break (EB) were measured in the same manner as in Examples 1 and 2, and the tensile product was determined. The results are shown in Table 4 below.

In Table 4, "mixing ratio" and "content ratio" indicate the ratio of each polymer to the total amount of polybutadiene used to prepare the sample piece. “1,2-PBD/1,3-BD ratio during 1,4 polymerization” is the mass ratio of 1,2-polybutadiene and 1,3-butadiene (1,2 -polybutadiene/1,3-butadiene). Abbreviations in Table 4 have the following meanings.
RB840: 1,2-polybutadiene (trade name “RB840”, manufactured by JSR Corporation)
BR740: High cis polybutadiene rubber (trade name “BR740”, manufactured by JSR Corporation)
1,2-PBD: 1,2-polybutadiene 1,4-PBD: 1,4-polybutadiene 1,3-BD: 1,3-butadiene

As shown in Table 4, the polybutadiene mixtures P1 and P2 of Examples 1 and 2 are superior to the polybutadiene of Comparative Example 1 and the polybutadiene mixtures of Comparative Examples 2 and 3 in terms of tensile strength, elongation and tensile product. Good evaluation results were obtained. In particular, the tensile product of the polybutadiene mixture P1 of Example 1 was about 1.7 times that of Comparative Example 1, 1.9 times that of Comparative Example 2, and about 2.2 times that of Comparative Example 3. Further, in the polybutadiene mixture P2 of Example 2, it was about 1.9 times that of Comparative Example 1, about 2.1 times that of Comparative Example 2, and about 2.4 times that of Comparative Example 3, which were greatly improved.

From the above, it was clarified that the polybutadiene mixture excellent in tensile strength, elongation and tensile product can be obtained according to the method for producing a polybutadiene mixture of the present invention.

Claims (8)

comprising a step Y of polymerizing 1,3-butadiene in the presence of 1,2-polybutadiene and a lanthanide catalyst;
Production of a polybutadiene mixture in which the mass ratio of 1,2-polybutadiene and 1,3-butadiene during the polymerization in step Y is 1,2-polybutadiene/1,3-butadiene=95/5 to 50/50 Method. further comprising step X of obtaining 1,2-polybutadiene by polymerizing 1,3-butadiene in the presence of a cobalt-based catalyst;
The method for producing a polybutadiene mixture according to claim 1, wherein the step Y is a step of polymerizing 1,3-butadiene in the presence of the 1,2-polybutadiene obtained in the step X and the lanthanide catalyst. . 3. The method for producing a polybutadiene mixture according to claim 2, wherein in the step X, the polymerization of 1,2-polybutadiene is terminated by adding an organoaluminum compound. 4. The method for producing a polybutadiene mixture according to claim 2, wherein step Y is a step of adding the lanthanoid catalyst to the reaction mixture obtained in step X to polymerize 1,3-butadiene. The method for producing a polybutadiene mixture according to any one of claims 2 to 4, wherein the cobalt-based catalyst contains a cobalt compound, a phosphine compound, and an organoaluminum compound. The method for producing a polybutadiene mixture according to any one of claims 1 to 5, wherein the 1,2-polybutadiene used in step Y is 1,2-syndiotactic polybutadiene. The method for producing a polybutadiene mixture according to any one of claims 1 to 6, wherein the lanthanide-based catalyst contains a lanthanide compound, an organoaluminum compound, and a halogen compound. The method for producing a polybutadiene mixture according to any one of claims 1 to 7, wherein the polybutadiene mixture contains 5 to 30% by mass of 1,4-polybutadiene.