JP2008163144A - Method for producing vinyl cis-polybutadiene rubber and vinyl cis-polybutadiene rubber - Google Patents

Abstract

The present invention provides a method for producing vinyl cis-polybutadiene rubber having further improved extrudability and tensile stress as compared with conventional vinyl cis-polybutadiene rubber.
A first step of preparing a mixture of dissolved 1,2-polybutadiene, 1,3-butadiene, and an inert organic solvent containing hydrocarbon as a main component was prepared in the first step. Second step of polymerizing 1,3-butadiene in cis-1,4 by adding a catalyst comprising water, an organoaluminum compound and a soluble cobalt compound, or a catalyst comprising a nickel compound, an organoaluminum compound and a fluorine compound to the mixture. And a third step of syndiotactic-1,2 polymerization of 1,3-butadiene in the polymerization reaction mixture obtained in the second step.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a vinyl cis-polybutadiene rubber excellent in extrudability and tensile stress.

  Conventionally, vinyl cis-polybutadiene rubber has been produced by converting 1,3-butadiene into cis-1 using a predetermined catalyst in an inert organic solvent mainly containing hydrocarbons such as benzene, toluene and xylene. , 4 polymerization, followed by syndiotactic-1,2 polymerization (hereinafter referred to as “1,2 polymerization”).

As the above manufacturing method, for example, Patent Document 1 and Patent Document 2 disclose the following methods. First, in the inert organic solvent, water, a soluble cobalt compound, and a general formula AlR _n X _3-n (where R is an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a cycloalkyl group, Is a halogen element, and n is a number from 1.5 to 2, and using a catalyst obtained from an organoaluminum chloride, 1,3-butadiene is cis-1,4 polymerized, and butadiene rubber is obtained. To manufacture. Next, 1,3-butadiene and the solvent are added to the polymerization system (however, either one of 1,3-butadiene and the solvent may be added, or none may be added) Furthermore, a catalyst obtained from a soluble cobalt compound, an organoaluminum compound represented by the general formula AlR ₃ (where R is an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a cycloalkyl group), and carbon disulfide. In the presence, 1,3-butadiene is polymerized 1,2 to produce vinyl cis-polybutadiene rubber.

Further, Patent Document 3, n-butane, cis-2-butene, in an inert organic solvent mainly composed of C ₄ fractions such trans-2-butene and butene-1, vinyl-cis - polybutadiene A method for producing rubber is disclosed. The 1,2-polybutadiene contained in the rubber composition produced by this method is a short fiber crystal, and the distribution of the major axis length of the short fiber crystal is such that 98% or more of the fiber length is less than 0.6 μm. 70% or more is less than 0.2 μm, and the obtained rubber composition improves the moldability, tensile stress, tensile strength, flex crack growth resistance and the like of cis-1,4-polybutadiene rubber. It is described that.

Japanese Patent Publication No.49-17666 Japanese Patent Publication No.49-17667 JP 2000-44633 A

  However, the vinyl cis-polybutadiene rubber produced by the methods of Patent Document 1 and Patent Document 2 is not sufficiently dispersed in the butadiene rubber as a matrix component of 1,2-polybutadiene short fiber crystals, There is a problem that sufficient effects cannot always be obtained in terms of formability, tensile stress, tensile strength, and resistance to flex crack growth.

  On the other hand, the vinyl cis-polybutadiene rubber produced by the method of Patent Document 3 is excellent in moldability, tensile stress, tensile strength, bending crack growth resistance, and the like. Improvement of various characteristics is desired.

  Accordingly, the present invention provides a method for producing a vinyl cis-polybutadiene rubber capable of producing a vinyl cis-polybutadiene rubber having further improved extrudability and tensile stress as compared with a conventional vinyl cis-polybutadiene rubber. The purpose is to provide.

  In order to achieve the above object, the present inventors have conducted extensive research, and as a result, when 1,3-butadiene is polymerized in cis-1,4, -By preparing a mixture of butadiene and an inert organic solvent mainly composed of hydrocarbons in advance, vinyl cis with improved extrudability and tensile stress compared to conventional vinyl cis-polybutadiene rubber. -It has been found that polybutadiene rubber can be produced. That is, the present invention adjusts the first step and the first step to prepare a mixture of dissolved 1,2-polybutadiene, 1,3-butadiene, and an inert organic solvent containing hydrocarbon as a main component. A catalyst comprising water, an organoaluminum compound and a soluble cobalt compound, or a catalyst comprising a nickel compound, an organoaluminum compound and a fluorine compound is added to the resulting mixture to polymerize 1,3-butadiene in a cis-1,4 polymerization. A vinyl cis-polybutadiene rubber comprising two steps and a third step of syndiotactic-1,2 polymerization of 1,3-butadiene in the polymerization reaction mixture obtained in the second step It is a manufacturing method.

  In the method for producing vinyl cis-polybutadiene rubber according to the present invention, the 1,2-polybutadiene is preferably syndiotactic-1,2-polybutadiene, and the melting point of the 1,2-polybutadiene is 100 ° C. It is preferable that it is -200 degreeC.

In the third step, the polymerization reaction mixture obtained in the second step contains a soluble cobalt compound, a general formula AlR ₃ (wherein R is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a cycloalkyl group). It is preferable to perform syndiotactic-1,2 polymerization of 1,3-butadiene in the presence of a catalyst comprising an organoaluminum compound represented by (A) and carbon disulfide.

  According to the method for producing a vinyl cis-polybutadiene rubber according to the present invention, it is possible to produce a vinyl cis-polybutadiene rubber having further improved extrudability and tensile stress as compared with a conventional vinyl cis-polybutadiene rubber. it can. When the obtained vinyl cis-polybutadiene rubber is used for tires and the like, workability can be improved by its excellent workability in the production process.

  The method for producing vinyl cis-polybutadiene rubber according to the present invention comprises a predetermined catalyst in a mixture of dissolved 1,2-polybutadiene, 1,3-butadiene, and an inert organic solvent containing hydrocarbon as a main component. And cis-1,4 polymerization of 1,3-butadiene, followed by 1,2 polymerization to produce a vinyl cis-polybutadiene rubber.

First step 1,2-polybutadiene used in the method for producing vinyl cis-polybutadiene rubber according to the present invention is a cobalt compound, an organoaluminum compound represented by the general formula AlR ₃ , carbon disulfide, and, if necessary, alcohol. , Aldehyde, ketone, ester, nitrile, sulfoxide, amide and phosphoric acid ester, and a catalyst consisting of one or more compounds selected from the group consisting of phosphoric acid ester and polymerizing 1,3-butadiene. The 1,2-polybutadiene has a 1,2 structure content of preferably 40 to 99%, particularly preferably 50 to 90%. The 1,2-polybutadiene is preferably syndiotactic-1,2-polybutadiene. The melting point of the 1,2-polybutadiene is preferably 100 ° C. to 200 ° C., and more preferably 100 ° C. to 180 ° C. Moreover, 0.1-5 are preferable and, as for the reduced viscosity ((eta) sp / c) of the said 1, 2- polybutadiene, 0.3-3 are especially preferable.

  Examples of the inert organic solvent used in the method for producing vinyl cis-polybutadiene rubber according to the present invention include aromatic hydrocarbons such as toluene, benzene and xylene, and aliphatic hydrocarbons such as n-hexane, butane, heptane and pentane. , Alicyclic hydrocarbons such as cyclohexane and cyclopentane, the above olefin compounds and olefinic hydrocarbons such as cis-2-butene and trans-2-butene, hydrocarbon spirits such as mineral spirits, solvent naphtha and kerosene, And halogenated hydrocarbon solvents such as methylene chloride. Further, 1,3-butadiene monomer itself may be used as a polymerization solvent.

  Among the above inert organic solvents, toluene, cyclohexane, and a mixture of cis-2-butene and trans-2-butene are preferably used.

  In the method for producing vinyl cis-polybutadiene rubber according to the present invention, a mixture of dissolved 1,2-polybutadiene, 1,3-butadiene, and an inert organic solvent containing hydrocarbon as a main component is 1, It may be prepared by dissolving 1,2-polybutadiene in 3-butadiene and the inert organic solvent. When 1,2-polybutadiene is difficult to dissolve, it is heated to 30 ° C. to 180 ° C. to dissolve. Alternatively, a mixture may be prepared by synthesizing and dissolving 1,2-polybutadiene using the above catalyst system in a mixture of 1,3-butadiene and the inert organic solvent.

Second Step Next, the concentration of water in the mixture adjusted in the first step is adjusted. The water concentration is preferably in the range of 0.1 to 1.4 mol, particularly preferably 0.2 to 1.2 mol, per mol of the organoaluminum compound used in the cis-1,4 polymerization. Outside this range, the catalytic activity is lowered, the cis-1,4 structure content is lowered, and the molecular weight is abnormally low or high. Further, outside the above range, it is not preferable because the generation of gel during polymerization cannot be suppressed, so that the gel adheres to the polymerization tank and the continuous polymerization time cannot be extended. A known method can be applied as a method of adjusting the moisture concentration. A method of adding and dispersing through a porous filter medium (Japanese Patent Laid-Open No. 4-85304) is also effective.

  An organoaluminum compound is added to the mixture obtained by adjusting the water concentration as described above. Examples of the organoaluminum compound include trialkylaluminum, dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum sesquibromide, alkylaluminum sesquibromide, and alkylaluminum dichloride.

Of the above organoaluminum compounds, trialkylaluminum represented by the general formula AlR ₃ (where R is a hydrocarbon group having 1 to 10 carbon atoms) can be preferably used. Examples of trialkylaluminums include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctyl Mention may be made of aluminum, triphenylaluminum, tri-p-tolylaluminum and tribenzylaluminum. The alkyl groups in the trialkylaluminum may be the same as or different from each other.

  In addition to the above organoaluminum compounds, dialkylaluminum chlorides such as dimethylaluminum chloride and diethylaluminum chloride, organoaluminum halogen compounds such as sesquiethylaluminum chloride and ethylaluminum dichloride, diethylaluminum hydride, diisobutylaluminum hydride and sesquiethylaluminum hydride An organoaluminum hydride compound can also be used. Two or more kinds of these organoaluminum compounds can be used in combination.

The amount of the organoaluminum compound used is 0.1 mmol or more per mole of 1,3-butadiene, particularly 0 when cis-1,4 polymerization is carried out using a catalyst system comprising water, an organoaluminum compound and a soluble cobalt compound. It is preferably 5 to 50 mmol. In addition, when cis-1,4 polymerization is performed using a catalyst system composed of a nickel compound, an organoaluminum compound, and a fluorine compound, the amount is 1 × 10 ⁻⁵ to 1 × 10 ⁻¹ mol per mol of 1,3-butadiene. It is preferable.

  Next, a soluble cobalt compound is added to the mixture to which the organoaluminum compound has been added, and 1,3-butadiene is polymerized in a cis-1,4 manner. Soluble cobalt compounds are those that are soluble in an inert organic solvent or liquid 1,3-butadiene based on hydrocarbons or that can be uniformly dispersed, for example, cobalt (II) acetylacetonate and cobalt (III) Cobalt β-diketone complexes such as acetylacetonate, cobalt β-keto acid ester complexes such as cobalt acetoacetic acid ethyl ester complex, organic compounds having 6 or more carbon atoms such as cobalt octoate, cobalt naphthenate and cobalt benzoate Cobalt halides such as cobalt salts of carboxylic acids, cobalt chloride pyridine complexes and cobalt chloride ethyl alcohol complexes are used. The amount of the soluble cobalt compound used is preferably 0.001 mmol or more, more preferably 0.005 mmol or more, per mol of 1,3-butadiene. Further, the molar ratio (Al / Co) of the organoaluminum compound to the soluble cobalt compound is 10 or more, and particularly preferably 50 or more.

  Further, instead of the soluble cobalt compound, 1,3-butadiene may be polymerized cis-1,4 by adding a nickel compound and a fluorine compound to a mixture to which an organoaluminum compound is added. In this case, water may or may not be added as a component of the cis-1,4 polymerization catalyst.

As the nickel compound, a nickel salt or complex is preferably used. Particularly preferred are nickel halides such as nickel chloride and nickel bromide, nickel salts of inorganic acids such as nickel nitrate, nickel carboxylic acid having 1 to 18 carbon atoms such as nickel octylate, nickel acetate, nickel octoate, Nickel naphthenate, nickel malonate, nickel bisacetylacetonate and trisacetylacetonate, nickel complexes such as ethyl acetoacetate, nickel halide triarylphosphine complex, trialkylphosphine complex, pyridine complex and picoline complex Examples include organic base complexes and various complexes such as ethyl alcohol complexes. The amount of the nickel compound used is preferably 1 × 10 ⁻⁷ to 1 × 10 ⁻³ mol per mol of 1,3-butadiene.

As the fluorine compound, boron trifluoride ether, alcohol, or a mixture of these mixtures, or hydrogen fluoride ether, alcohol, or a mixture of these complexes is preferably used. Particularly preferred are boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, hydrogen fluoride diethyl etherate, and hydrogen fluoride dibutyl etherate. The amount of the fluorine compound used is preferably 1 × 10 ⁻⁴ to 1 mol per 1 mol of 1,3-butadiene.

  The temperature for cis-1,4 polymerization of 1,3-butadiene is more than 0 ° C and not more than 100 ° C, preferably 10 to 100 ° C, more preferably 20 to 100 ° C. The polymerization time is preferably in the range of 10 minutes to 2 hours. The cis-1,4 polymerization is preferably performed so that the polymer concentration after the cis-1,4 polymerization is 5 to 26% by weight. The polymerization is carried out by stirring and mixing the solution in a polymerization tank (polymerizer). As a polymerization tank used for the polymerization, a polymerization tank equipped with a high-viscosity liquid stirring apparatus, for example, an apparatus described in JP-B-40-2645 can be used.

  At the time of cis-1,4 polymerization, known molecular weight regulators, for example, non-conjugated dienes such as cyclooctadiene, allene, methylallene (1,2-butadiene), or α-olefins such as ethylene, propylene, and butene-1 Can be used. Moreover, in order to further suppress the production | generation of the gel at the time of superposition | polymerization, a well-known gelation inhibitor can be used.

The cis-1,4 structure content of the polybutadiene obtained by cis-1,4 polymerization is preferably 90% or more, particularly preferably 95% or more. The Mooney viscosity (ML _{1 + 4} , 100 ° C., hereinafter referred to as “ML”) is preferably 10 to 130, particularly preferably 15 to 80. The 5% toluene solution viscosity (Tcp) is preferably 25 to 250.

  Moreover, the polybutadiene obtained by cis-1,4 polymerization contains substantially no gel content.

Third step Next, 1,3-butadiene in the polymerization reaction mixture obtained in the second step is subjected to syndiotactic-1,2. At that time, 1,3-butadiene may or may not be added to the obtained cis-1,4 polymer. Further, when the 1, 2 polymerization is performed, the organoaluminum compound represented by the general formula AlR ₃ and carbon disulfide, and, if necessary, the above-described soluble cobalt compound are added to add 1,3-butadiene to 1, It is preferable to perform two polymerizations, and water may be added to the polymerization system when performing the first and second polymerizations.

As the organoaluminum compound represented by the general formula AlR ₃ , trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triphenylaluminum, and the like are preferable. The organoaluminum compound is preferably 0.1 mmol or more, particularly 0.5 to 50 mmol, per mol of 1,3-butadiene. The concentration of carbon disulfide is 20 mmol / L or less, particularly preferably 0.01 to 10 mmol / L. As an alternative to carbon disulfide, a known phenyl isothiocyanate or xanthate compound may be used. Water is preferably added to the polymerization system after contacting with the organoaluminum compound. The amount of water added is preferably 0.1 to 1.5 mol per mol of the organoaluminum compound.

  The temperature for the 1,2 polymerization is preferably -5 to 100 ° C, particularly preferably -5 to 80 ° C. 1 to 50 parts by weight, preferably 1 to 20 parts by weight of 1,3-butadiene is added to 100 parts by weight of the cis polymerization solution to the polymerization system for 1,2 polymerization. Thereby, the yield of 1,2-polybutadiene at the time of 1,2 polymerization can be increased. The polymerization time is preferably in the range of 10 minutes to 2 hours. The 1,2 polymerization is preferably performed so that the polymer concentration after the 1,2 polymerization is 9 to 29% by weight. The polymerization is carried out by stirring and mixing the polymerization solution in a polymerization tank (polymerizer). As the polymerization tank used for 1,2 polymerization, the viscosity becomes higher during the 1,2 polymerization, and the polymer tends to adhere to the polymerization tank. For example, a polymerization tank equipped with a high-viscosity liquid stirring device, for example, disclosed in JP-B-40-2645. Can be used.

  After the polymerization reaction reaches a predetermined polymerization rate, a known anti-aging agent can be added according to a conventional method. Anti-aging agents include phenol-based 2,6-di-t-butyl-p-cresol (BHT), phosphorus-based trinonylphenyl phosphite (TNP), and sulfur-based 4.6-bis (octylthio). Methyl) -o-cresol and dilauryl-3,3′-thiodipropionate (TPL). These may be used singly or in combination of two or more, and the addition of the antioxidant is 0.001 to 5 parts by weight with respect to 100 parts by weight of vinyl cis-polybutadiene.

  For the polymerization reaction, a large amount of an alcohol such as methanol and ethanol, or a polar solvent such as water is added to the polymerization solution, an inorganic acid such as hydrochloric acid and sulfuric acid, an organic acid such as acetic acid and benzoic acid, or hydrogen chloride gas is polymerized The reaction is stopped using a method known per se, such as a method of introducing the solution. The resulting vinyl cis-polybutadiene is then separated, washed and subsequently dried according to conventional methods.

  The proportion of boiling n-hexane insoluble matter (HI) in the vinyl cis-polybutadiene thus obtained is preferably 3 to 60% by weight, particularly preferably 10 to 40% by weight. The boiling n-hexane soluble component is cis-1,4-polybutadiene having a microstructure of 80% or more.

  In the vinyl cis-polybutadiene rubber produced by the above method, the dispersibility of 1,2-polybutadiene having a melting point of 170 ° C. or higher in the cis-polybutadiene rubber as a matrix component is remarkably improved. As a result, the obtained vinyl cis-polybutadiene rubber is excellent in properties such as extrudability and tensile stress. Further, when compared with the method for producing a vinyl cis-polybutadiene rubber according to Patent Document 3, the inert organic solvent that can be used is not limited to a specific type, and further, a vinyl cis-polybutadiene having equivalent characteristics even at a higher polymerization temperature. The effect that a cis-polybutadiene rubber can be produced is obtained.

  EXAMPLES Hereinafter, although the manufacturing method of the vinyl cis-polybutadiene rubber based on this invention is demonstrated based on an Example, this invention is not limited to the following Example. The physical properties of the base rubber, compound and vulcanized product of vinyl cis-polybutadiene rubber produced by the method for producing vinyl cis-polybutadiene rubber according to the present invention were measured as follows.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) was measured by a Mooney viscometer (SMV-202, manufactured by Shimadzu Corporation) in accordance with JIS K6300, with a preheat 1 minute measurement at 100 ° C. for 4 minutes.

  The melting point, heat of fusion and crystallization temperature of boiling n-hexane insoluble matter (HI, syndiotactic-1,2-polybutadiene component) are the values when the sample is about 10 mg and the heating rate is 10 ° C./min. It measured with the differential scanning calorimeter (Shimadzu make, DSC-50).

  Boiling n-hexane insoluble matter (HI) is the amount of heat of fusion measured with a differential scanning calorimeter (manufactured by Shimadzu Corp., DSC-50) and the measured H.H. Obtained by the I measurement method. Obtained from I calibration curve. Measured H.V. In the I measurement method, 5 g of precisely weighed vinyl cis-polybutadiene was poured into 350 ml of n-hexane stirred with a stirrer and chopped into the size of a match, and dissolved. Next, this solution was filtered with a cylindrical filter paper (86R, 20 × 100 mm, manufactured by Advantech) that was precisely weighed in advance. The insoluble part remaining on the filter paper was subjected to Soxhlet extraction with n-hexane for 3 hours, vacuum-dried at 60 ° C. for 3 hours, and precisely weighed. The ratio (% by weight) of I was calculated.

  ηsp / c was measured as a reduced viscosity at 135 ° C. from a 0.20 g / dl tetralin solution as a measure of the molecular weight of the boiling n-hexane insoluble matter.

The die / swell ratio is a cross-sectional area of the compound during extrusion at a shear rate of 100 ° C. and 100 sec ⁻¹ using a processability measuring device (manufactured by Monsanto, MPT) as a measure of the extrusion processability of the compound. And the ratio of the die orifice cross-sectional area (where L / D = 1.5 mm / 1.5 mm). The index was calculated with Comparative Example 1 as 100. The smaller the value, the better the extrudability.

  For the tensile modulus, the tensile modulus M100 was measured according to JIS K6251. The index was calculated with Comparative Example 1 as 100. The larger the value, the higher the tensile stress.

(Example 1)
A 1.9 L stainless steel autoclave equipped with helical blades and finished with a nitrogen replacement has a melting point of 127.2 ° C. (peak top temperature) and a heat of fusion of 26 measured with a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation). After introducing 0.5 g of syndiotactic-1,2-polybutadiene (SPB) powder having 0.0J / g and ηsp / c of 0.73, nitrogen substitution was performed 5 times at 5 kg / cm ² . Next, 1,050 ml of a mixed solution (FB) having a weight ratio of 1,3-butadiene, 2-butene and cyclohexane of 3: 3: 4 was introduced. The stirring speed was 600 rpm. 1.05 ml of a cyclohexane solution (0.25 M) of carbon disulfide (CS ₂ ) and 49.5 mg of water were added and held at 25 ° C. for 30 minutes. Next, 2.25 ml of a solution of diethylaluminum chloride (DEAC) in cyclohexane (2.0 M), 0.75 ml of a cyclohexane solution of dilauryl-3,3′-dithiopropionate (TPL) (0.02 M), and 1, 2.58 ml of a cyclohexane solution (5.0 M) of 5-cyclooctadiene (COD) was added and reacted at 25 ° C. for 5 minutes. Thereafter, the temperature of the solution was raised to 60 ° C., and 1.5 ml of a cyclohexane solution (5.0 mM) of cobalt octenoate (Co (Oct) ₂ ) was immediately added to carry out cis-1,4 polymerization at 60 ° C. for 20 minutes. went. Next, 3.375 ml of a cyclohexane solution (2.0 M) of triethylaluminum (TEA) was added, 46.8 mg of water after 2 minutes, and a cyclohexane solution of cobalt octenoate (Co (Oct) ₂ ) after another 5 minutes ( 0.05M) 1.8 ml was added, and 1,2 polymerization was carried out at 60 ° C. for 20 minutes. The polymerization was stopped by adding 5 ml of a 5% solution of “Irganox” (registered trademark) 1076 (Ciba Specialty Chemicals), which is a 1: 1 mixture of n-heptane and ethanol, and letting the autoclave cool with ice water. I went under pressure. After the pressure returned to normal pressure, the polymer was collected in a vat and vacuum dried at 100 ° C. for 5 hours. The cis-1,4 polymerization conditions are shown in Table 1, the 1,2 polymerization conditions are shown in Table 2, and the polymerization results are shown in Table 3.

(Example 2)
1.0g of addition amount of syndiotactic-1,2-polybutadiene (SPB) powder at the time of cis-1,4 polymerization, addition amount of cyclohexane solution (5.0M) of 1,5-cyclooctadiene (COD) Except that the addition amount of water at the time of 1,2 polymerization is 54.0 mg and the addition amount of cyclohexane solution (0.05M) of cobalt octenoate (Co (Oct) ₂ ) is 2.0 ml. A vinyl cis-polybutadiene rubber was produced in the same manner as in Example 1. The cis-1,4 polymerization conditions are shown in Table 1, the 1,2 polymerization conditions are shown in Table 2, and the polymerization results are shown in Table 3.

(Example 3)
Addition amount of syndiotactic-1,2-polybutadiene (SPB) powder at the time of cis-1,4 polymerization is 1.5 g, addition amount of cyclohexane solution (5.0 M) of 1,5-cyclooctadiene (COD) The vinyl cis-polybutadiene rubber was produced in the same manner as in Example 1 except that 2.80 ml of the polymerization time was changed to 30 minutes. The cis-1,4 polymerization conditions are shown in Table 1, the 1,2 polymerization conditions are shown in Table 2, and the polymerization results are shown in Table 3.

Example 4
A 1.9 L stainless steel autoclave equipped with helical blades and finished with a nitrogen replacement has a melting point of 127.2 ° C. (peak top temperature) and a heat of fusion of 26 measured with a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation). After introducing 5.6 g of syndiotactic-1,2-polybutadiene (SPB) powder having 0.0J / g and ηsp / c of 0.73, nitrogen substitution was performed 5 times at 5 kg / cm ² . Next, 1,200 ml of a mixed liquid (FB) having a weight ratio of 1,3-butadiene, 2-butene and cyclohexane of 3: 3: 4 was introduced. The stirring speed was 600 rpm. 1.4 ml of a cyclohexane solution (0.25 M) of carbon disulfide (CS ₂ ) and 65.9 mg of water were added, and the mixture was kept at 25 ° C. for 30 minutes. Next, 3.0 ml of a cyclohexane solution (2.0 M) of diethylaluminum chloride (DEAC), 1.0 ml of a cyclohexane solution (0.02 M) of dilauryl-3,3′-dithiopropionate (TPL), and 1, 4.68 ml of a cyclohexane solution (5.0 M) of 5-cyclooctadiene (COD) was added and reacted at 25 ° C. for 5 minutes. Thereafter, the temperature of the solution was raised to 60 ° C., and 2.0 ml of a cyclohexane solution (5.0 mM) of cobalt octenoate (Co (Oct) ₂ ) was immediately added to carry out cis-1,4 polymerization at 60 ° C. for 30 minutes. went. Next, 4.5 ml of a cyclohexane solution (2.0 M) of triethylaluminum (TEA) was added, and 2.0 ml of a cyclohexane solution (0.05 M) of cobalt octenoate (Co (Oct) ₂ ) was added after 2 minutes. The 1,2 polymerization was carried out at 60 ° C. for 18 minutes. The polymerization was stopped by adding 5 ml of a 5% solution of “Irganox” (registered trademark) 1076 (manufactured by Ciba Specialty Chemicals), which is a 1: 1 mixture of n-heptane and ethanol, and releasing the autoclave while cooling it with ice water. I went under pressure. After the pressure returned to normal pressure, the polymer was collected in a vat and vacuum dried at 100 ° C. for 5 hours. The cis-1,4 polymerization conditions are shown in Table 1, the 1,2 polymerization conditions are shown in Table 2, and the polymerization results are shown in Table 3.

(Comparative Example 1)
As inert organic solvents, benzene -C ₄ fraction mixed solvent (benzene 30 wt% and cis-2-butene C ₄ fraction 39 wt% of the mixed solvent mainly composed of) a vinyl-cis produced using the - It is a polybutadiene rubber (UBEPOL-VCR412, manufactured by Ube Industries). When the physical properties of this vinyl cis-polybutadiene rubber were measured, ML _{1 + 4} = 43, boiling n-hexane insoluble matter (HI) = 11.1%, H.I. Melting point of I = 201.4 ° C., H.I. Ηsp / c of I = 1.87, ML _{1 + 4} = 32 soluble in boiling n-hexane soluble, cis-1,4 structure soluble in boiling n-hexane = 97.5%.

  The vinyl cis-polybutadiene rubbers obtained in Examples 1 to 4 and Comparative Example 1 were kneaded by adding carbon black, process oil, zinc white, stearic acid and anti-aging agent with a plast mill according to the formulation table of Table 4. The primary blending was carried out, and then the secondary blending in which the vulcanization accelerator and sulfur were added by a roll was carried out to prepare a blend. Using this formulation, the die swell ratio was measured. Further, this blend was molded according to the desired physical properties, press vulcanized at 150 ° C. to obtain a vulcanized product, and then the tensile elastic modulus M100 was measured. Table 5 shows the index of Comparative Example 1 as 100 for the physical properties measurement results of the blend and vulcanizate. From the result of Table 5, when the vinyl cis-polybutadiene rubber obtained in Examples 1 to 4 is used, the extrudability and tensile stress of the compound and the vulcanizate are improved as compared with Comparative Example 1. I understand that.

(Example 5)
A 1.9 L stainless steel autoclave with helical blades and a nitrogen replacement, a melting point of 124 ° C. (peak top temperature) measured by a differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50), and a heat of fusion of 33.5 J After introducing 0.5 g of syndiotactic-1,2-polybutadiene (SPB) powder having a / g and ηsp / c of 0.62, nitrogen substitution was performed 5 times at 5 kg / cm ² . Next, 700 ml of a mixed liquid (FB) in which the weight ratio of 1,3-butadiene, 2-butene and cyclohexane was 3: 3: 4 was introduced. The stirring speed was 600 rpm. Carbon disulfide (CS ₂ ) in cyclohexane (0.25 M) (0.7 ml) and water (30.7 mg) were added and held at 25 ° C. for 30 minutes. Next, 1.5 ml of a cyclohexane solution (2.0 M) of diethylaluminum chloride (DEAC), 0.5 ml of a cyclohexane solution (0.02 M) of dilauryl-3,3′-dithiopropionate (TPL) and 1,5 -1.7 ml of cyclooctadiene (COD) in cyclohexane (5.0 M) was added and reacted at 25 ° C for 5 minutes. Thereafter, the temperature of the solution was raised to 60 ° C., and 1.0 ml of a cyclohexane solution (5.0 mM) of cobalt octenoate (Co (Oct) ₂ ) was immediately added to carry out cis-1,4 polymerization at 60 ° C. for 20 minutes. went. Next, 2.25 ml of a cyclohexane solution (2.0 M) of triethylaluminum (TEA) was added, 54.0 mg of water after 2 minutes, and a cyclohexane solution of cobalt octenoate (Co (Oct) ₂ ) after another 5 minutes ( 0.05M) 1.2 ml was added, and 1,2 polymerization was carried out at 60 ° C. for 20 minutes. The polymerization was stopped by adding 5 ml of a 5% solution of “Irganox” (registered trademark) 1076 (manufactured by Ciba Specialty Chemicals), which is a 1: 1 mixture of n-heptane and ethanol, and releasing the autoclave while cooling it with ice water. I went under pressure. After the pressure returned to normal pressure, the polymer was collected in a vat and vacuum dried at 100 ° C. for 5 hours. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

(Example 6)
Example except that the amount of syndiotactic-1,2-polybutadiene (SPB) powder added during cis-1,4 polymerization was 1.0 g and the amount of water added during 1,2 polymerization was 27.0 mg. The vinyl cis-polybutadiene rubber was produced in the same manner as in No. 5. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

(Example 7)
Except that the amount of syndiotactic-1,2-polybutadiene (SPB) powder added during cis-1,4 polymerization was 2.0 g, and the amount of water added during 1,2 polymerization was 9.0 mg. The vinyl cis-polybutadiene rubber was produced in the same manner as in No. 5. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

(Example 8)
Example except that the amount of syndiotactic-1,2-polybutadiene (SPB) powder added at the time of cis-1,4 polymerization was 3.12 g and the amount of water added at the time of 1,2 polymerization was 18.0 mg. The vinyl cis-polybutadiene rubber was produced in the same manner as in No. 5. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

Example 9
A vinyl cis-polybutadiene rubber was produced in the same manner as in Example 5 except that the amount of syndiotactic-1,2-polybutadiene (SPB) powder added during cis-1,4 polymerization was 3.12 g. went. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

(Comparative Example 2)
A vinyl cis-polybutadiene rubber was produced in the same manner as in Example 5 except that no syndiotactic-1,2-polybutadiene (SPB) powder was added during the cis-1,4 polymerization. Table 6 shows the cis-1,4 polymerization conditions, Table 7 shows the 1,2 polymerization conditions, and Table 8 shows the polymerization results.

  Electron micrographs of the vinyl cis-polybutadiene rubber obtained in Examples 5 to 9 and Comparative Example 2 are shown in FIGS. The electron micrograph was observed as follows. The vinyl cis-polybutadiene rubber is cut into a 2 mm square sample and immersed in a solution of sulfur monochloride: carbon disulfide = 1: 1 for 72 hours to select the double bond of the cis portion of the vinyl cis-polybutadiene rubber. Vulcanized. The vulcanizate, which had been thoroughly washed with acetone and then air-dried for 3 days, was cut into ultrathin sections with a microtome, and the double bond of the vinyl part of the VCR was stained with osmium tetrachloride vapor. A transmission electron microscope (Hitachi, H -7100). As is clear from the photograph, the vinyl cis-polybutadiene rubbers of Examples 5 to 9 as compared with Comparative Example 2 are cis-polybutadiene rubbers that are matrix components of 1,2-polybutadiene having a melting point of 170 ° C. or higher. Dispersibility into the inside is remarkably improved.

6 is an electron micrograph according to Example 5. 6 is an electron micrograph according to Example 6. 10 is an electron micrograph according to Example 7. 10 is an electron micrograph according to Example 8. 10 is an electron micrograph according to Example 9. 4 is an electron micrograph according to Comparative Example 2.

Claims (5)

A first step of preparing a mixture of dissolved 1,2-polybutadiene, 1,3-butadiene, and an inert organic solvent based on hydrocarbon;
A catalyst comprising water, an organoaluminum compound and a soluble cobalt compound, or a catalyst comprising a nickel compound, an organoaluminum compound and a fluorine compound is added to the mixture prepared in the first step, and 1,3-butadiene is converted to cis-1. , 4-polymerization second step,
A third step of syndiotactic-1,2 polymerization of 1,3-butadiene in the polymerization reaction mixture obtained in the second step;
A method for producing a vinyl cis-polybutadiene rubber, comprising:   2. The method for producing vinyl cis-polybutadiene rubber according to claim 1, wherein the 1,2-polybutadiene is syndiotactic-1,2-polybutadiene.   The method for producing a vinyl-cis-polybutadiene rubber according to claim 1 or 2, wherein the melting point of the 1,2-polybutadiene is 100 ° C to 200 ° C. In the third step, the polymerization reaction mixture obtained in the second step contains a soluble cobalt compound, a general formula AlR ₃ (where R is an alkyl group having 1 to 6 carbon atoms, a phenyl group or a cycloalkyl group). 4. The vinyl according to claim 1, wherein 1,3-butadiene is polymerized in syndiotactic-1,2 in the presence of a catalyst comprising an organoaluminum compound represented by the formula (I) and carbon disulfide. A method for producing cis-polybutadiene rubber.   A vinyl cis-polybutadiene rubber produced by the method for producing a vinyl cis-polybutadiene rubber according to any one of claims 1 to 4.