JPH0147487B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for efficiently polymerizing a conjugated diene compound and a vinyl aromatic compound using an organolithium catalyst to produce a conjugated diene polymer having a relatively large number of vinyl bonds. Generally, when a conjugated diene and a vinyl aromatic compound are copolymerized using an organolithium catalyst, a block copolymer is usually obtained, but a random copolymer is preferable as a general-purpose rubber such as for tires. It is well known to use ethers, thioethers, tertiary amines, and other polar compounds to
-15386). However, in order to obtain a product with a relatively large number of vinyl bonds, it is necessary to use a relatively large amount of a polar compound, and the polymerization rate generally tends to be difficult to increase. Also, recently, JP-A-55-
Although it is polybutadiene in Publication No. 40734,
The use of allene compounds as Mooney viscosity modifiers in obtaining rubbers with substantial vinyl bonding and improved cold flow properties has been demonstrated.
However, although Mooney viscosity may be controlled in this method, the polymerization rate is low and the polymerization is carried out at a low temperature, which results in poor productivity and inefficiency. Under such circumstances, the present inventors took advantage of the features of organolithium catalysts to substantially reduce the polymerization rate.
The present invention was achieved by intensive investigation into a method for obtaining an effective conjugated diene polymer that can be produced using a smaller amount of catalyst than conventional methods in order to obtain a polymer having 100% of the same Mooney viscosity. That is, the present invention provides a method for polymerizing one or more conjugated diene compounds or a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent using an organolithium catalyst. One or more compounds selected from the following and (B) an allene compound represented by the general formula H ₂ C=C=CHR (R in the formula represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms) are used as an organolithium catalyst. of
This is a method for producing a conjugated diene polymer, characterized in that polymerization is carried out in the presence of 0.1 to 0.9 times the mole amount. The features of the present invention are that when obtaining a conjugated diene polymer with a relatively high vinyl content, the polymerization rate is substantially 100%, which is extremely efficient; It is possible to produce polymers with a small amount of catalyst. Incidentally, molecular weight such as Mooney viscosity can be substantially sufficiently controlled by the amount of catalyst. The organolithium catalyst used in the present invention is a hydrocarbon bonded with at least one lithium atom, such as ethyllithium, propyllithium, n-butyllithium, sec-butyllithium,
tert-butyllithium, phenyllithium, propenyllithium, 1,4-dithylio-n-butane, 1,5-dithylio-n-pentane, 1,2-
These include dilithio-1,2-phenylethane, and conventionally known ones and polyalkyllithiums are used. Particularly preferred examples are n-butyllithium and sec-butyllithium. These organolithium catalysts may be used not only alone but also as a mixture of two or more. The amount of organolithium catalyst used depends on the molecular weight of the resulting polymer, but it is usually
0.1 to 2 mmol as lithium atoms per 100 g,
Preferably, about 0.3 to 1.5 mmol is used. The conjugated diene compound used in the present invention is, for example, 1,3-butadiene, 2-methyl-1,3-
Butadiene (isoprene), 2,3-dimethyl-
Examples include 1,3-butadiene and 1,3-pentadiene, with 1,3-butadiene and isoprene being particularly preferred. The vinyl aromatic compound used in the present invention is
Examples include styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, α-methylstyrene, o-ethylstyrene, p-tert-butylstyrene, vinylnaphthalene, vinylanthracene, etc., with styrene being particularly preferred. The ratio of the conjugated diene compound to the vinyl aromatic compound used in the present invention is usually preferably 50% or less of the total monomers in order to obtain a rubbery polymer. Moreover, the above-mentioned conjugated diene compound and vinyl aromatic compound may each be a mixture of two or more kinds. The hydrocarbon solvent used in the present invention is not particularly limited as long as it does not deactivate the organolithium catalyst, but examples include n-butane, n-pentane,
iso-pentane, n-hexane, n-heptane,
Examples include iso-octane, cyclohexane, and ethylcyclohexane, with hexane and cyclohexane being particularly preferred. Two or more of these hydrocarbon solvents can be used in combination. Further, the hydrocarbon solvent is usually used in a proportion of 1 to 20 times that of the monomer. Ethylene glycol dialkyl ethers and tertiary diamines used in the present invention, such as ethylene glycol dimethyl ether, ethylene glycol diether ether, ethylene glycol ethyl butyl ether, ethylene glycol dibutyl ether, ethylene glycol propyl butyl ether, ethylene glycol diamyl ether, N, N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N,N',N'-tetramethylpropanediamine, N,N,N',N'- Tetramethylbutanediamine and the like, with ethylene glycol dibutyl ether and N,N,N',N'-tetramethylethylenediamine being preferred. These compounds may be used alone or in combination of two or more. The amount added depends on the amount of vinyl bonds in the polymer to be obtained and the temperature, but the molar ratio is usually 0.3 to 20 times that of the organolithium catalyst. The allene compound used in the present invention has the general formula
It is represented by H ₂ C=C=CHR (R in the formula is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms). The arenes represented by this formula are, for example, propadiene,
1,2-butadiene, 1,2-pentadiene,
1,2-hexadiene, 1,2-heptadiene,
1,2-octadiene, etc., with propadiene and 1,2-butadiene being particularly preferred. The amount added is 0.1 to 0.9 times the mole of the organolithium catalyst. Preferably 0.1 to 0.8 mol, more preferably 0.2
to 0.7 mole. If the amount of arenes added is too large, the polymerization rate will be too low, and if it is too small, the catalyst support will be difficult to change from normal when obtaining a polymer with the same Mooney viscosity, and the effects of the present invention will not be brought about. In the method of the present invention, polymerization is usually carried out at 25°C to
Can be done in the range of 180℃. Preferably between 50℃ and 130℃
℃, more preferably 70°C to 120°C. If the polymerization temperature is low, the polymerization rate will be slow, and if it is too high, it will be difficult to produce a polymer with a substantially high vinyl content. The time required for polymerization is not particularly limited, but is generally 5 minutes to 5 hours. The pressure in the reaction system may be sufficient to maintain the reaction mixture in the liquid phase;
Usually the pressure is about 1 to 20 atmospheres, but under special conditions the reaction can be carried out at higher or lower pressures. The polymerization reaction can be carried out continuously or batchwise, but in the case of general-purpose rubbers, it is preferable to carry it out continuously in terms of productivity, quality controllability, etc. The polymerization reaction is preferably carried out under an inert gas atmosphere such as nitrogen gas or argon gas, and care must be taken to avoid contaminating the polymerization system with impurities that would deactivate the organolithium catalyst, such as water, oxygen, alcohol, etc. is preferred. After the polymerization is completed, a polymerization terminator such as water or alcohol and an antiaging agent are added, and the resulting polymer is separated, washed, and dried to obtain the desired polymer. The conjugated diene polymer obtained by the method of the present invention can be suitably used in fields where general-purpose synthetic rubbers are used. The present invention will be specifically described below with reference to some examples, but these are not intended to limit the invention. Examples 1 to 3 and Comparative Examples 1 and 2 Using a stainless steel stirrer with an internal volume of 5 and a reactor with a jacket, 1,
A continuous copolymerization reaction was carried out using 3-butadiene and styrene (75/25 weight ratio), hexane as a solvent, butyllithium as a catalyst, and ethylene glycol dibutyl ether and 1,2-butadiene as additives in the proportions shown in Table 1. I went. The temperature inside the polymerization vessel was controlled to be 95°C, and the monomer was supplied using a metering pump so that the average residence time was 50 minutes. The amount of catalyst is approximately 35 or less with Mooney viscosity.
Adjusted to fall within the 40 range. The polymerization rate in the table was determined by gas chromatography of the sample at the exit of the polymerization vessel, the Mooney viscosity was determined using a Mooney viscometer, the bonded styrene was determined using an ultraviolet spectrophotometer, and the microstructure of the butadiene portion was determined using an infrared spectrophotometer. Measured using

[Table] As is clear from the table, the combination of additives within the scope of the present invention has a polymerization rate of substantially 100%,
The amount of polymer obtained with 1 g of catalyst is also large. on the other hand,
In Comparative Example 1, which did not use 1,2-butadiene, the amount of polymer obtained with 1 g of catalyst was small, and in Comparative Example 2, which contained too much 1,2-butadiene, the polymerization rate was extremely poor, and the Mooney viscosity was low at 29, making it difficult to reduce the amount of catalyst. Even if I lowered it, it didn't change much, and the catalyst efficiency was low. Examples 4 to 6 and Comparative Example 3 By the method according to Examples 1 to 3, the polymerization temperature was set to 100
Polymerization was carried out using the types and amounts of additives shown in Table 2. As is clear from Table 2, experiments within the scope of the present invention are excellent in terms of polymerization rate and efficiency, but ethylene glycol methyl ether outside the scope of the present invention has a low polymerization rate and is not practical.

[Table] Example 7 Polybutadiene was obtained using a method similar to Example 1 at a polymerization temperature of 110° C. and using 1.5 times the mole of tetramethylethylenediamine as an additive relative to the catalyst. The polymerization rate is over 99%, and 1g of catalyst produces polymer.
Over 2000g was obtained. The Mooney viscosity was 50 and the vinyl bond was 37%. Example 8 Polybutadiene was obtained in the same manner as in Example 2 at a polymerization temperature of 70° C. and an average residence time of 70 minutes. The polymerization rate was 98.5%, and 2300 g of polymer was obtained with 1 g of catalyst. The Mooney viscosity is 75 and the vinyl bond is 56.
It was %.

Claims (1)

[Claims] 1. When polymerizing one or more conjugated diene compounds or a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent using an organolithium catalyst, (A) ethylene glycol dialkyl ethers or a third one or more compounds selected from class diamines and (B)
An allene compound represented by the general formula H ₂ C=C=CHR (R in the formula represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms) is used as an organolithium catalyst.
A method for producing a conjugated diene polymer, which comprises polymerizing the conjugated diene polymer in the presence of 0.1 to 0.9 moles.