JPS6244761B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polybutadiene with a high content of 1 and 2 structures. More specifically, the present invention deals with the 1.2 structure content and the cis-1.4 structure content.
The present invention relates to a method for producing polybutadiene having a high structural content, a low trans-1.4 structural content, and a high molecular weight. It is well known that improving fuel efficiency and safety are major research issues in the automobile industry, and various studies are being conducted from the perspective of improving automobile tires as a means of solving these research issues. . Generally, styrene-butadiene rubber (SBR) or butadiene rubber (BR) is mainly used as a rubber material for the tread of automobile tires. The former styrene-butadiene rubber has practically satisfactory impact resilience and glass transition temperature, as well as high wet skid resistance and
In other words, it has the property of being resistant to slipping on roads wet with water, etc., and has traditionally been used in large quantities as a rubber material for treads. On the other hand, the latter butadiene rubber has a lower glass transition temperature (Tg) compared to SBR.
is significantly lower, showing an even higher impact resilience value. That is, it has been studied and actually used as a rubber material that contributes to improving fuel efficiency because of its low rotational resistance. However, butadiene rubber has the disadvantage of poor wet skid resistance. Therefore, when butadiene rubber is used as a tread rubber material to improve fuel efficiency, the problem arises that the wet skid resistance of the tire decreases, leading to a decrease in vehicle safety.
On the other hand, although styrene-butadiene rubber has sufficiently high wet skid resistance properties, it has a problem in that it cannot contribute to improving fuel efficiency because of its limited impact resilience. A method has been considered in which the two are mixed in order to take advantage of their respective strengths and compensate for their weaknesses, but in the case of mixed use, characteristics are only obtained depending on the mixing ratio of the two. In addition, 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 has improved impact resistance, so it is widely sold as an impact-resistant polystyrene resin. has been done. The polybutadiene used to produce this impact-resistant polystyrene resin is generally butadiene (1.
3-butadiene) obtained by polymerizing cis-1.
4 structure content is 30 to 35%, trans-1 and 4 structure content is 50 to 60%, and 1 and 2 structure content is 10 to 20%.
(low cis polybutadiene), and cis-polybutadiene obtained by polymerizing butadiene in the presence of cobalt or nickel catalysts.
1.4 structure content is 96-98%, trans-1.4
Structural content is 1-2%, 1・2-structural content is 1
~2% polybutadiene (high cis polybutadiene) is known. The former low-cis polybutadiene has a high glass transition point (usually -70°C) and mainly has a trans-1,4 structure, so it cannot be said to have sufficient rubber properties. The polystyrene resin obtained using this method is not fully satisfactory in terms of impact resistance. On the other hand, the latter high-cis polybutadiene is 1.2
Due to its low structural content of 1 to 2%, its reactivity with styrene monomers (graft reactivity) is low, and polystyrene resins obtained using high-cis polybutadiene and styrene monomers are also fully satisfactory in terms of impact resistance. It has the disadvantage that it is not possible. In other words, polybutadiene used as a raw material for polystyrene resin with high impact resistance is 1.
It is necessary that both the 2 structure content and the cis-1.4 structure content are high. In addition to the above-mentioned 1.2 structure content and cis-1.4 structure content, it is also important that the polybutadiene used as a raw material for the impact-resistant polystyrene resin has a high molecular weight. 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. Therefore, an object of the present invention is to provide a method for producing polybutadiene that has both a high 1,2 structure content and a high cis-1,4 structure content, and also has excellent properties as a rubber. It is something. The present invention is characterized in that 1,3-butadiene is polymerized in the presence of a catalyst system consisting of a cobalt dithiocarbamate compound, a halogen-containing organic aluminum compound, and water. -1.4 structure content is 50% or more, trans-1.4 structure content is 2% or less, and intrinsic viscosity [η] (toluene, 30°C) is 1 or more. . That is, the present invention achieves both a high 1/2 structure content and a high cis-1/4 structure content by polymerizing butadiene using a specific catalyst system, and also has properties as a rubber. This made it possible to produce polybutadiene with excellent properties. The polybutadiene produced by the present invention has a high 1/2 structure content and a high cis-1/2 structure content as described above.
4 structural content and excellent rubber properties, so when used as a rubber material for tire treads, it has the advantage of having sufficiently high wet skid resistance properties and high impact resilience. Therefore, it is possible to obtain a tire that is preferable in terms of safety and improved fuel efficiency. Furthermore, it is suitable for manufacturing commercially available rubber products, and can be used not only as a rubber material for treads of automobile tires but also as other tire components. In addition, the styrene resin obtained from the polybutadiene and styrene monomer obtained by the present invention has excellent impact resistance such as excellent Izot impact strength and markedly improved Dupont impact strength, so it is particularly excellent as an impact resistant material. It becomes something. Next, the present invention will be explained in detail. The catalyst system utilized in the present invention includes a cobalt dithiocarbamate compound, a halogen-containing organoaluminium compound, and water. By polymerizing 1,3-butadiene using this catalyst system, mainly 1,2 structure and cis-
The polybutadiene is composed of a 1,4 structure, has an extremely low content of trans-1,4 structures, and has a high molecular weight. The cobalt dithiocarbamate compound used in the present invention has the general formula []: (However, R ¹ and R ² may be the same or different from each other, and each represents a chain or cyclic alkyl group having 1 to 20 carbon atoms, and R ¹ and R ² may be mutually connected. may form a ring containing a nitrogen atom, and can be represented by n=2 to 3). In the general formula [ ], R ¹ and R ² are each generally selected from an alkyl group having 1 to 12 carbon atoms, preferably a lower alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, Mention may be made of propyl, butyl, pentyl, hexyl and cyclohexyl. Also, R ¹ and R ₂
Examples of a group in which these groups are interconnected to form a ring containing a nitrogen atom include a piperidyl group and a pipecolyl group. Specific examples of the cobalt dithiocarbamate compound used in the present invention include the following compounds. Cobalt dizzyciocarbamate, cobalt dizzytiocarbamate, cobalt dizzthiocarbamate, cobalt dubarchycarbamate, cobalt dublt dizyclico -cheocarbamate, cobalt pipecorulinic acid cobalt pipecorulinic acid, cobalt penta -ryclediocarbamate. Cobalt Methyl Penta Range Cheerooca -Bamate) Cobalt exists as divalent, trivalent or a mixture of divalent and trivalent. However, in the present invention, it is preferable to use trivalent cobalt dithiocarbamate or a mixture containing trivalent cobalt dithiocarbamate as a main component. The cobalt dithiocarbamate compound used in the present invention is a known compound, and can be produced, for example, by reacting sodium dialkyldithiocarbamate with cobalt chloride.
The detailed method for producing the cobalt dithiocarbamate compound is described in the following literature. M.Delepine Bull.soc.chim.［4］, 3 , 643−
652 (CA 2 , 2691) L. Compin, Bull.soc.chim. 27 , 464−469
(1920) (CA 14 , 3025) In addition, especially regarding the production of trivalent cobalt dithiocarbamate, please refer to "New Experimental Chemistry Course 8" published by Maruzen.
The description on page 1582 is helpful. The halogen-containing organoaluminum compound used in the present invention has the general formula []: AlRnX ₃ -n [] (wherein R is a lower alkyl group having 1 to 6 carbon atoms,
represents a phenyl group or a cycloalkyl group, n
is a number between 1.5 and 2). In the general formula [], examples of R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, and a phenyl group. Specific examples of the halogen-containing organoaluminum compound used in the present invention include dialkylaluminum halides such as diethylaluminum monochloride, diethylaluminum monobromide, and diisobutylaluminum monochloride, and alkylaluminum sesquihalides such as ethylaluminum sesquichloride. can be mentioned. When polymerizing butadiene using the catalyst system of the present invention, the cobalt dithiocarbamate compound is preferably used in an amount of 0.001 to 0.5 mmol per mol of butadiene. Further, the molar ratio of the cobalt dithiocarbamate compound to the halogen-containing organoaluminum compound is 1:5 to 1:
1000, particularly preferably in the range of 1:10 to 1:350. In the catalyst system of the present invention, the presence of water is an essential component for the polymerization reaction to proceed smoothly, and the molar ratio (H ₂ O/Al) of water and halogen-containing organoaluminum compound used is 0.01:1 to 0.7. :1, especially
It is preferably in the range of 0.1:1 to 0.6:1.
Note that it is also possible to increase the 1.2 structure content by increasing the molar ratio (H ₂ O/Al) between water and halogen-containing organic aluminum in the catalyst system of the present invention. Polymerization solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, butane, butene, n
- Polymerization solvents such as aliphatic hydrocarbons such as hexane, n-heptane, cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, etc. can be used, and also polymerization solvents such as cyclooctadiene, 1,2-butadiene, allene, etc. Known molecular weight regulators can also be used. The polymerization reaction temperature of butadiene is 5 to 80℃, especially 20℃.
The temperature is preferably ~70℃, and the polymerization reaction time is usually 10
Minutes to 10 hours. In preparing the catalyst system used in the present invention, it is desirable that the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound be brought into contact in the presence of butadiene. That is, in preparing the catalyst system, the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound are brought into contact in a system in which butadiene is not present;
Polybutadiene obtained by a polymerization reaction using a catalyst system prepared by mixing this with water is 1.2
The structural content tends to decrease. In particular, in a catalyst system prepared through an operation of aging a cobalt dithiocarbamate compound and a halogen-containing organoaluminum compound by contacting them at high temperature or even at low temperature for a long time in the absence of butadiene, This trend will become even more pronounced. Therefore, when preparing the catalyst system used in the present invention, it is desirable to carry out the contact operation between the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound in the presence of butadiene. Furthermore, when the contact operation between the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound is carried out in the absence of butadiene,
It is desirable to set conditions such that ripening between these two components does not proceed much, such as a temperature of 50° C. or lower and a contact time of 5 minutes or less in the absence of butadiene. The polymerization reaction of the present invention can be carried out in accordance with conventionally known polymerization reaction operations for butadiene (1,3-butadiene). However, when carrying out the present invention, for the above-mentioned reasons, there is a method in which water is dissolved in a mixture of butadiene and a solvent, and then a cobalt dithiocarbamate compound and a halogen-containing organoaluminum compound are simultaneously added to initiate polymerization, or Of the three components, water, a halogen-containing organoaluminum compound, and a cobalt dithiocarbamate compound, it is preferable to use a method in which either the halogen-containing organoaluminum compound or the cobalt dithiocarbamate compound is added last to initiate polymerization. The lower the polymerization temperature and the lower the molar ratio [Al/CO] of the halogen-containing organoaluminum compound and the cobalt dithiocarbamate compound, the higher the 1.2 structure content of the obtained polybutadiene becomes. Therefore, by adjusting the polymerization temperature and the above molar ratio, polybutadiene with a high content of 1/2 structures can be easily obtained. The 1.2 structure content of polybutadiene can also be increased by increasing the molar ratio of water to halogen-containing organic aluminum (H ₂ O/Al). After the polymerization reaction is completed, if desired, an antiaging agent may be added to the reaction solution, and then polybutadiene can be extracted using a known method, such as a method of treating the reaction solution with alcohol, hot water, or water. can. By the above method according to the present invention, 1.
2 structure content is 7 to 50% (especially 10 to 50%), cis-1,4 structure content is 50% or more (especially 50 to 88
%), trans-1/4 structure content is 2% or less,
Polybutadiene having an intrinsic viscosity [η] (toluene, 30°C) of 1 or more (particularly 1 to 10) can be easily produced. As mentioned above, the polybutadiene obtained by the present invention has excellent wet skid resistance properties and impact resilience properties, so it can be used in the same manner as ordinary polybutadiene rubber or blended with styrene-butadiene rubber, using appropriate compounding agents and additives. By vulcanizing the mixture after adding the agent, it is possible to obtain a rubber material particularly suitable as a rubber material for treads of automobile tires. Among the above polybutadienes, polybutadiene with a 1/2 structure content in the range of 10 to 25% is particularly suitable for 2 to 25 parts by weight (preferably 2 to 25 parts by weight).
20 parts by weight) and 75-98 parts by weight of styrene (preferably
An excellent impact-resistant polystyrene resin can be obtained by radical polymerizing a mixture consisting of 80 to 98 parts by weight) using a bulk method or a bulk/suspension method, preferably a bulk/suspension method. . In addition, the 1/2 structure content described in this specification,
Cis-1/4 structure content and trans-1/4
The structural content (collectively referred to as microstructure) is a value calculated from the IR spectrum and NMR spectrum, and the intrinsic viscosity [η] is a value measured in toluene at a temperature of 30°C. Next, Examples and Reference Examples of the present invention will be described. Examples 1 to 3 After replacing the air in an autoclave with a capacity of 1 with dry nitrogen gas, 200 g of dehydrated benzene was added to the autoclave.
ml and 62 g of 1,3-butadiene, added a specified amount of water (listed in Table 1), stirred at 30°C for 30 minutes,
The water was dissolved. Next, 0.78 mmol of diethylaluminum monochloride was added, and then 0.007 mmol of cobalt diethyldithiocarbamate was added at 60°C to initiate the polymerization reaction. This polymerization reaction was carried out by stirring the reaction solution at 60°C for 30 minutes. The above-mentioned cobalt diethyldithiocarbamate can be obtained by reacting sodium diethyldithiocarbamate and cobalt chloride in water, drying the resulting precipitate, and then using the benzene-soluble cobalt diethyldithiocarbamate as cobalt diethyldithiocarbamate. used. The elemental analysis values of this benzene-soluble portion were C: 36.99%, H: 6.00%, and N: 8.26%, indicating that cobalt in the compound was trivalent. After the polymerization reaction was completed, 5 ml of methanol containing a small amount of 2,6-di-t-butyl-p-cresol was added to the reaction solution to stop the polymerization reaction, and another 300 ml of methanol was added to remove the produced polymer. The polymer was precipitated and dried under reduced pressure at room temperature for 24 hours. The microstructure and intrinsic viscosity of the obtained polymer were measured. These results are shown in Table 1.

[Table] Example 4 After dissolving water in a mixture of benzene and butadiene according to Example 2, cobalt diethyldithiocarbamate was added thereto, and diethylaluminum monochloride was then added at 60°C. A polymerization reaction was carried out in the same manner as in 2, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table. Example 5 After dissolving water in a mixture of benzene and butadiene according to Example 2, cobalt diethyldithiocarbamate and diethylaluminum monochloride were added simultaneously at 60°C, and then the same solution as in Example 2 was added. A polymerization reaction was carried out, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Examples 6 to 8 A butadiene polymerization reaction was carried out in accordance with Example 2, except that the amount of cobalt diethyldithiocarbamate was changed as shown in Table 3, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table. Further, for reference, the data of Example 2 described above is also shown.

[Table] Examples 9-10 The amount of dehydrated benzene is 250ml, the amount of butadiene is
30g, and the amount of cobalt diethyldithiocarbamate was changed as shown in Table 4.
A butadiene polymerization reaction was carried out according to Example 2, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Examples 11 to 14 A butadiene polymerization reaction was carried out in accordance with Example 2, except that the type of cobalt dithiocarbamate compound was changed as shown in Table 5, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Examples 15 to 17 The amount of water added was changed as shown in Table 6,
The amount of diethylaluminum monochloride is 1.56
mmol, and the addition temperature of cobalt diethyldithiocarbamate to 30°C to initiate the polymerization reaction.
The polymerization reaction of butadiene was carried out in the same manner as in Examples 1 to 3 except that it was carried out at 30°C, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Examples 18-19 A butadiene polymerization reaction was carried out in accordance with Example 16, except that the amount of diethylaluminium monochloride was changed as shown in Table 7, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Example 20 Example except that the amount of water was changed to 0.90 mmol
A polymerization reaction of butadiene was carried out according to No. 19, and the produced polymer was recovered. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in the table.

[Table] Example 21 After replacing the air in an autoclave with a capacity of 5 with dry nitrogen gas, 1300 g of dehydrated benzene was added to the autoclave.
ml and 420 g of 1,3-butadiene were added, 1.4 mmol of water was added, and the mixture was stirred at 30°C for 30 minutes to dissolve the water. Then diethyl aluminum monochloride
5.2 mmol and 1,5-cyclooctadiene 56.0
After adding 0.2 mmol of cobalt diethyldithiocarbamate at 50°C,
The polymerization reaction was started. This polymerization reaction
This was carried out by stirring at 50°C for 30 minutes. After the polymerization reaction, 2,6-di-t-butyl-p
- 30 ml of methanol containing a small amount of cresol was added to the reaction solution to stop the polymerization reaction, and 2 portions of methanol was further added to precipitate the formed polymer, and this polymer was dried under reduced pressure at room temperature for 24 hours. The microstructure and intrinsic viscosity of the obtained polymer were measured. The results are shown in Table 9.

[Table] Examples 22 to 23 Same as Example 21 except that the addition temperature and polymerization temperature of cobalt diethyldithiocarbamate were changed to 60°C, and the amount of cobalt diethyldithiocarbamate added was changed as shown in Table 10. A polymerization reaction of butadiene was carried out, and the produced polymer was taken out. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in Table 10.

[Table] Examples 24-25 Amount of diethylaluminum monochloride
6.0 mmol, the addition temperature and polymerization temperature of cobalt diethyldithiocarbamate were changed to 60°C, and the amount of cobalt diethyldithiocarbamate added was changed as shown in Table 11.
A butadiene polymerization reaction similar to that in 21 was carried out, and the resulting polymer was recovered. The microstructure and intrinsic viscosity of the obtained polymer were
Shown in Table 11.

[Table] Reference Example 1 The polybutadiene produced in Examples 21 to 23 was vulcanized at 150°C for 30 minutes using the following composition.
Various physical properties of the vulcanizate were measured. In addition, commercially available high cis polybutadiene rubber (high cis polybutadiene rubber)
BR: Cis-1/4 structure content 97.0%, trans-1/4 structure content 1.0%, 1/2 structure content 2.0
%, [η] = 2.0), and commercially available styrene-butadiene rubber (SBR: styrene monomer unit content =
23.5%) was similarly vulcanized (however, the vulcanization time for SBR was 60 minutes) to obtain a vulcanized product, and various physical properties of the vulcanized product were measured. Compound composition for vulcanization ( parts by weight) Rubber 100 HAF carbon 50 High aromatic oil 10 Zinc oxide 5 Stearic acid 2 Anti-aging agent 1 Vulcanization accelerator 1 Sulfur 1.5 However, the anti-aging agent is Antigen manufactured by Sumitomo Chemical Co., Ltd.
In AS, the vulcanization accelerator is N-cyclohexyl-2-
Benzothiazole sulfenamide. The measurement results are shown in Table 12.

【table】

[Table] Reference Example 2 Impact-resistant polystyrene resins were produced using the polybutadiene produced in Examples 23 to 25 by the method shown below, and impact resistance tests were conducted on each of them. In addition, commercially available high cis polybutadiene rubber (high cis polybutadiene rubber)
BR: Cis-1/4 structure content 95.9%, trans-1/4 structure content 2.0%, 1/2 structure content 2.1
%, [η] = 1.8), and commercially available low-cis polybutadiene rubber (low-cis BR: cis-1,4 structure content
37.5%, trans-1/4 structure content 50.5%,
From the 1.2 structure content 12.0%, [η] = 1.9),
Impact resistant polystyrene resins were produced in a similar manner and impact resistance tests were conducted on each. Manufacturing method of impact-resistant polystyrene resin After replacing the air in the separable flask in step 1 with nitrogen gas, 570 g of styrene and polybutadiene
30g (5% by weight) was added and dissolved, and then n-
After adding 0.3 g of dodecyl mercaptan and 11.4 g of n-butyl stearate, polymerization was carried out at 120°C with stirring until the styrene polymerization rate reached 30%.
Next, 0.5% by weight polyvinyl alcohol aqueous solution
Add the reaction solution to 600 ml, pour this into an autoclave, add 0.93 g of benzoyl peroxide and 0.93 g of dicumyl peroxide, and incubate at 100°C for 2 hours, then at 125°C for 3 hours, and then at 140°C for 2 hours.
Polymerization was carried out under stirring for hours. Bead-shaped polymers are collected from this reaction mixture by filtration, washed with water, dried, and pelletized using an extruder to form polystyrene resin.
Got 500g. The measurement results are shown in Table 13.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the catalyst preparation process in the polybutadiene production method of the present invention.

Claims (1)

[Scope of Claims] 1. 1.3-Butadiene is polymerized in the presence of a catalyst system consisting of a cobalt dithiocarbamate compound, a halogen-containing organoaluminium compound, and water, and the content of 1.2 structures is 7 to 50.
%, a cis-1.4 structure content of 50% or more, a trans-1.4 structure content of 2% or less, and an intrinsic viscosity [η] (toluene, 30°C) of 1 or more. 2. The method for producing polybutadiene according to claim 1, characterized in that in preparing the catalyst system, the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound are brought into contact in the presence of 1,3-butadiene. 3 The cobalt dithiocarbamate compound has the general formula []: (However, R ¹ and R ² may be the same or different from each other, and each represents a chain or cyclic alkyl group having 1 to 20 carbon atoms, and R ¹ and R ² may be mutually connected. The method for producing polybutadiene according to claim 1 or 2, which may form a ring containing a nitrogen atom, and n = 2 to 3. . 4 0.001 cobalt dithiocarbamate compound constituting the catalyst system per mole of butadiene.
3. The method for producing polybutadiene according to claim 1 or 2, wherein the amount is used in a range of 0.5 mmol to 0.5 mmol. 5. The polybutadiene according to claim 1 or 2, wherein the molar ratio of the cobalt dithiocarbamate compound and the halogen-containing organoaluminum compound in the catalyst system is in the range of 1:5 to 1:1000. Production method. 6 Claim 1, characterized in that the molar ratio of water to halogen-containing organoaluminum compound in the catalyst system is in the range of 0.01:1 to 0.7:1.
The method for producing polybutadiene according to item 1 or 2.