JPS6129604B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polybutadiene using a novel catalyst. The copolymer obtained by adding polybutadiene to styrene monomer and performing a radical polymerization reaction has not only the excellent properties of polystyrene but also improved impact resistance, so it is widely sold as an impact-resistant polystyrene resin. . The polybutadiene used to produce this impact-resistant polystyrene resin is generally obtained by polymerizing 1,3-butadiene using an alkyl lithium as a catalyst, and has a cis-1,4 structure content of 30 to 35%. Trans 1,4-structure content is 50~
Polybutadiene (low cis polyphtadiene) with a 1,2 structure content of 10 to 20% and a cis-1,4 structure content obtained by polymerizing 1,3-butadiene with a cobalt or nickel catalyst. but
96-98%, trans-1,4-structure content from 1 to
2%, and polybutadiene (high cis polybutadiene) with a 1,2-structure content of 1 to 2%. Since the above-mentioned low-cis polybutadiene has a high glass transition point (usually -70°C), the impact-resistant polystyrene resin obtained using this low-cis form is not fully satisfactory in terms of impact resistance. On the other hand, the above-mentioned high cis polybutadiene is 1,2
Since the structural content is as low as 1 to 2%, the reactivity with styrene monomers (graft reactivity) is low, and impact-resistant polystyrene resins obtained using high-cis polybutadiene are also fully satisfactory in terms of impact resistance. It has the disadvantage that it is not a real thing. In addition, as the properties of polybutadiene, the above 1 and 2
In addition to the -structure or cis-1,4 structure content, it is important that the molecular weight is high. Impact-resistant polystyrene resins obtained using low-molecular-weight polybutadiene are not fully satisfactory in terms of impact resistance because the rubber properties of polybutadiene are difficult to develop. When an organic phosphorus compound or an organic sulfur compound is added as a fourth component to a catalyst system of a cobalt compound, a halogen-containing organoaluminum compound, and water for the production of high-cis polybutadiene, the content of 1,2 structures is generally relatively high. High polybutadiene is obtained. However, as the content of the 1,2 structure increases, the molecular weight decreases, resulting in a nearly liquid form that cannot be practically used as a rubber (for example, JP-A No. 50-91689). The catalyst system of the present invention has a cobalt compound, a halogen-containing organoaluminium compound, water, and further a thiuram compound as a fourth component. When 1,3-butadiene is polymerized using this catalyst system, it has a relatively high content of both cis-1,4 structure content and 1,2 structure content,
Moreover, high molecular weight polybutadiene can be obtained. This polybutadiene is suitably used as the polybutadiene for producing the above-mentioned impact-resistant polystyrene resin. If the method of the present invention is used, the content of each structure in polybutadiene will vary depending on the polymerization conditions, such as a 1,2 structure content of 4 to 50% and a cis-1,4 structure content of 48 to 50%.
96%, and the trans-1,4 structure content can be varied within a range of 2% or less. In addition, polybutadiene has an intrinsic viscosity [η] (toluene, 30℃) of 1 to
10, preferably in the range of 1.5 to 7. Cobalt compounds as catalyst components used in the polymerization reaction of the present invention include cobalt β-diketone complexes such as cobalt acetylacetonate and cobalt acetylacetonate, cobalt β-keto acid esters such as cobalt acetoacetic acid ethyl ester, and cobalt β-keto acid esters such as cobalt acetoacetic acid ethyl ester. Examples include cobalt salts of organic carboxylic acids having 6 or more carbon atoms such as octoate, cobalt naphthenate, and cobalt benzeate, and cobalt halide complexes such as cobalt chloride pyridine complexes and cobalt chloride ethyl alcohol complexes. The halogen-containing organoaluminum compound is represented by the general formula AlRnX ₃ - _o (where R is an alkyl group, phenyl group, or cycloalkyl group having 1 to 6 carbon atoms, and n is a number from 1.5 to 2). It is a compound. Examples of halogen-containing organoaluminum compounds include diethylaluminum monochloride, diethylaluminum monobromide,
Examples include dialkyl aluminum halides such as diisobutylaluminum monochloride and alkyl aluminum sesquihalides such as ethylaluminum sesquichloride. Thiuram compounds are (R is an alkyl group having 1 to 6 carbon atoms, a phenyl group, a cycloalkyl group, or a pentamethylene group, and n is a number of 1 to 4). Examples of the thiuram compound include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide, and the like. When 1,3-butadiene is polymerized using a catalyst obtained from a cobalt compound, a halogen-containing organoaluminum compound, water, and a thiuram compound, 1,3-butadiene alone may be used as the monomer, or 1,3-butadiene alone may be used as the monomer. ,3-butadiene
Up to 50% by weight (preferably up to 20% by weight) of isoprene, 1,3-pentadiene, 2,3-
Dimethyl-1,3-butadiene or the like may be used instead. The amount of catalyst used for 1,3-butadiene polymerization is:
The cobalt compound is preferably at least 0.001 mmol, particularly preferably at least 0.005 mmol, per mole of 1,3-butadiene. The molar ratio (Co/Al) of cobalt compound to halogen-containing organoaluminium is preferably from 1:5 to 1:1000, particularly from 1:15 to 1:500. The molar ratio of cobalt compound to thiuram compound is preferably from 1:0.01 to 1:10, particularly from 1:0.1 to 1:2. The molar ratio of water to halogen-containing organoaluminum is
A ratio of 0.01:1 to 1:1, especially 0.1:1 to 0.5:1 is preferred. When polymerizing 1,3-butadiene, aromatic hydrocarbons such as benzene, toluene, and xylene, butane, butene, n-heptane,
The polymerization may be carried out in a polymerization solvent such as an aliphatic hydrocarbon such as n-hexane or n-octane, or an aliphatic hydrocarbon such as cyclohexane. The polymerization temperature of 1,3-butadiene is 5 to 100℃,
In particular, the temperature is preferably 20 to 80°C, and the polymerization pressure may be normal pressure or higher. When polymerizing 1,3-butadiene, known molecular weight modifiers, such as non-conjugated dienes such as cyclooctadiene and allene, or α-olefins such as ethylene, propylene, styrene, and butene-1, can be used. . After the polymerization reaction is completed, polybutadiene can be removed by adding an antiaging agent and treating with alcohol, hot water or water in a known manner. The polybutadiene of the present invention can be produced by, for example, a mixture of 2 to 25 parts by weight, preferably 2 to 20 parts by weight, of polybutadiene and 75 to 98 parts by weight, preferably 80 to 98 parts by weight of styrene. An impact-resistant polystyrene resin can be obtained by radical polymerization, preferably by bulk suspension method. Alternatively, the polybutadiene of the present invention exhibits excellent properties when blended as is with styrene-butadiene rubber (SBR) and used for tire tread. Example 1 Add 62 g of 1,3-butadiene to 200 ml of benzene, then add 0.44 mmol of water and stir at 30°C for 30 minutes to dissolve the water. Then, diethylaluminum monochloride
1.56 mmol, tetramethylthiuram disulfide 0.01 mmol, and cobalt octenoate 0.02
After sequentially adding millimoles, the mixture was stirred at 30° C. for 30 minutes to polymerize 1,3-butadiene. After the polymerization reaction was completed, a large amount of methanol containing 0.1% of 2,6-di-tert-butyl-4-methylphenol was added to the polymerization solution, and the precipitate was dried under reduced pressure at room temperature for 24 hours to obtain 13.02 g of polybutadiene. . This polybutadiene has a 1,2 structure content of 7.1% and a cis-1,4 structure content of 7.1%.
The structural content is 92.0%, the trans-1,4 structural content is 0.9%, and the intrinsic viscosity [η] (toluene, 30
℃, hereinafter the same) was 6.25. Examples 2 and 3, Comparative Example 1 A polymerization reaction was carried out in the same manner as in Example 1 except that the amount of tetramethylthiuram disulfide was changed. The results obtained are shown in Table 1.

[Table] Examples 4 and 5 A polymerization reaction was carried out in the same manner as in Example 2, except that the order of addition of the catalyst was changed. The results obtained are shown in Table 2.

【table】

[Table] Examples 6 and 7 A polymerization reaction was carried out in the same manner as in Example 4, except that the amount of tetramethylthiuram disulfide was changed. The results obtained are shown in Table 3.

[Table] Examples 8 and 9 A polymerization reaction was carried out in the same manner as in Example 5, except that the amount of tetramethylthiuram disulfide was changed. The results obtained are shown in Table 4.

[Table] Examples 10 and 11 A polymerization reaction was carried out in the same manner as in Example 2, except that the amount of cobalt octoate was changed. The results obtained are shown in Table 5.

[Table] Example 12 Example 2 except that 0.55 mmol of water and 1.95 mmol of diethylaluminum monochloride were used.
In the same manner as above, 13.00 g of polybutadiene was obtained. This polybutadiene has a cis-1,4 structure content.
92.3%, trans-1,4 structure content 0.8%,
The vinyl structure content was 6.9%, and the intrinsic viscosity [η] was 6.89. Example 13 19.62 g of polybutadiene was obtained in the same manner as in Example 2, except that the polymerization temperature was 40°C. This polybutadiene had a cis-1,4 structure content of 93.9%, a trans-1,4 structure content of 1.2%, a 1,2 structure content of 4.9%, and an intrinsic viscosity [η] of 5.14. Examples 14 and 15 A polymerization reaction was carried out in the same manner as in Example 2, except that cyclooctadiene was further added as a molecular weight regulator to the catalyst system of Example 2. The results are shown in Table 5.

[Table] Examples 16 and 17 The same procedure as in Example 2 was carried out, except that tetramethylthiuram monosulfide (abbreviated) or dipentamethylenethiuram tetrasulfide (abbreviated) was used as the thiuram compound. A polymerization reaction was carried out. The results are shown in Table 7.

[Table] Comparative Example 2 A polymerization reaction was carried out in the same manner as in Example 2 using another sulfur compound as the fourth component. The results are shown in Table 8.

【table】

Claims (1)

[Claims] 1. A method for producing polybutadiene by polymerizing 1,3-butadiene in the presence of a catalyst, using a catalyst obtained from a cobalt compound, a halogen-containing organoaluminium compound, water, and a thiuram compound as the catalyst. A method for producing polybutadiene, which comprises polymerizing butadiene.