JPH0653769B2 - Method for producing tin-carbon bond-containing conjugated diene polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a conjugated diene polymer rubber which is excellent in impact resilience and breaking strength of a vulcanized product and is excellent in thermal stability.

[Conventional technology]

Conjugated diene-based polymers containing tin-carbon bonds have impact resilience,
It is known that it has excellent breaking strength and is useful as a polymer for tire treads.

These conjugated diene-based polymers are obtained by polymerizing a conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound with an organolithium compound as an initiator in a hydrocarbon solvent, and then performing a coupling reaction using a halogenated-tin compound. (JP-B-44-4996, JP-A-57-87407, JP-A-57-55912).

[Problems to be solved by the invention]

However, when the coupling reaction with the conjugated diene polymer lithium is performed using the tin halide compound, all the halogen atoms in the tin halide compound are not consumed even under the condition of an excess amount of lithium atom equivalent to the halogen atom. Therefore, a polymer obtained by coupling a conjugated diene polymer lithium with a bifunctional or higher functional tin halide compound is a polymer which is coupled in a form containing unreacted halogen atoms. Such a polymer causes an increase in Mooney viscosity due to a partial gelation reaction during heating and drying, which makes it difficult to control the Mooney viscosity in production, and also reduces the thermal stability of raw rubber, resulting in a tin-carbon bond coupled during storage. However, there was a problem that the Mooney was cut and the Mooney viscosity was lowered. Due to such a problem, excellent properties such as impact resilience and breaking strength due to the inclusion of a tin-carbon bond in the polymer have not always been sufficiently exhibited.

In view of the above problems, the present inventors improve the thermal stability and storage stability of a conjugated diene polymer obtained by coupling with a tin halide compound, and improve the impact resilience and breaking strength of a vulcanized product. As a result of earnest research on the above, the inventors have found that the problem can be solved by reacting a tin halide compound and then further reacting with an N, N-dialkylaminoacetophenone compound, and completed the present invention.

[Means for solving problems]

That is, in the present invention, a conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound are polymerized in a hydrocarbon solvent with an organolithium compound as an initiator, and then halogen atom equivalent is 0.2 to 1. A tin-carbon bond-containing conjugated diene characterized by reacting with 0 equivalent of a tin halide compound and further reacting 0.1 to 1.0 mol of an N, N-dialkylaminoacetophenone compound with respect to 1 gram atom equivalent of lithium. It is a method for producing a polymer.

Hereinafter, the present invention will be described in detail.

Examples of the conjugated diene compound of the present invention include 1,3-butadiene, isoprene, 1,3-pentadiene and 2,3-dimethylbutadiene. Preferably 1,3-
It is butadiene. Examples of the vinyl aromatic compound include styrene, p-methylstyrene, vinyltoluene and the like, but styrene is preferable. Polymerization is carried out by conjugating a conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent with an organic lithium compound as an initiator at 0 ° to
Polymerization is carried out batchwise or continuously at a temperature in the range of 100 ° C. The content of the vinyl aromatic compound in the copolymer of the conjugated diene compound and the vinyl aromatic compound is 40% by weight or less.

This copolymer is a random copolymer, a tapered block copolymer, or a block copolymer of random copolymers having different vinyl aromatic compound contents. As the hydrocarbon compound of the polymerization solvent, hydrocarbon compounds such as hexane, heptane, octane, methylcyclopentane, cyclohexane, 2-methylbutene-1, and 2-methylbutene-2 are used alone or in a mixture. The amount is used in the range of 2 to 10 parts by weight per 1 part by weight of the monomer. Organolithium compounds as polymerization initiators are n-butyllithium, sec-butyllithium, tert-butyllithium, amyllithium,
Hexyl lithium, 1,4-dilithiobutane, 1,3-
Bis (1-lithio-1,3-dimethylpentyl) benzene, 1,1,4,4-tetraphenyl-1,4-dilithiobutane, 1,3-bis (1-lithio-3-methylpentyl) benzene, etc. Used. The amount is monomer 1
It is used in the range of 0.1 to 10 mmol per 00 g.
In addition, 1. of the conjugated diene polymer. , 2 or 3,4 structure in a hydrocarbon solvent to control diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, N, N, N ', N'-tetramethyl Ethers such as ethylenediamine, 1,2-dipiperidinoethane or tertiary amines can be present.

The reaction between a conjugated diene compound or a conjugated diene polymer anion obtained by polymerizing a conjugated diene compound and a vinyl aromatic compound with an organolithium compound as an initiator and a tin halide compound is a tin halide compound per 1 gram atom equivalent of lithium. It is carried out at 20 to 100 ° C. for 1 minute to 1 hour at 0.2 to 1.0 equivalent per halogen atom equivalent.

When the halogen atom equivalent of the tin halide compound is less than 0.2 equivalent, the vulcanizate has poor impact resilience, tensile strength and processability. The halogen atom equivalent of the tin halide compound is 1.0
If it exceeds the equivalent, the thermal stability of the raw rubber will be poor.

The conjugated diene-based polymer anion is preferably a butadienyl anion, and the conjugated diene-based polymer is bound by a tin-butadienyl bond by a reaction with a tin halide compound by making it a butadienyl anion.
A polymer having excellent tensile strength can be obtained.

Making the end of the conjugated diene polymer a butadienyl anion can be easily produced by adding a small amount of 1,3-butadiene after polymerization.

Examples of the tin halide compound are tetrachlorotin, tetrabromotin, trichlorobutyltin, trichloromethyltin, trichlorooctyltin, dibromodimethyltin, dichlorodimethyltin, dichlorodibutyltin, dichlorotin, 1,2bis (trichlorostannyl) ethane, 1,2-bis (methyldichlorostannylethane, 1,
4bis (trichlorostannyl) butane, 1,4bis (methyldichlorostannyl) butane, etc. are used.

After the reaction with the tin halide compound, the added N, N-dialkylaminoacetophenone compound reacts with the unreacted active lithium at the polymer terminal to introduce the N, N-dialkylaminoacetophenone compound at the polymer terminal. As a result, a polymer having excellent thermal stability and having excellent impact resilience and breaking strength of the vulcanized product can be obtained. The obtained tin-carbon bond-containing conjugated diene polymer also contains an N, N-dialkylaminoacetophenone compound-modified conjugated diene polymer.

The N, N-dialkylaminoacetophenone compound is added in the range of 0.1 to 1.0 mol per 1 gram atom equivalent of lithium, and the reaction is carried out at 20 to 100 ° C. for 5 minutes to 2 hours. If the amount of the N, N-dialkylaminoacetophenone compound is less than 0.1 mol per 1 gram atom equivalent of lithium, the thermal stability of the raw rubber and the impact resilience of the vulcanizate are poor, and if it exceeds 1.0 mol, the N, N-dialkyl compound. A large amount of unreacted aminoacetophenone compound remains in the polymer to reduce the impact resilience of the vulcanizate.

As the N, N-disubstituted aminoaromatic compound, p, p'-
-N, N-dialkylamino aromatic ketone compounds such as bis (dimethylamino) benzophenone, p, p'-bis (diethylamino) benzophenone, p-dimethylaminobenzophenone, p-dimethylaminoacetophenone, m-dimethylaminoacetophenone, p -N, N-dialkylamino aromatic aldehyde compounds such as -dimethylaminobenzaldehyde, p-diethylaminobenzaldehyde and 3,5-bis (dihexylamino) benzaldehyde. Here, of the above N, N-disubstituted aminoaromatic compounds, examples of the N, N-dialkylaminoacetophenone compounds used in the present invention are p-dimethylaminoacetophenone and m-dimethylaminoacetophenone.

Among them, especially p-dimethylaminoacetophenone, m-
Carbon black is an N, N-dialkylaminoacetophenone compound such as dimethylaminoacetophenone, p-dimethylaminobenzaldehyde, p-diethylaminobenzaldehyde, N, N-dialkylaminoaromatic aldehyde compound such as 3,5-bis (dihexylamino) benzaldehyde. When kneaded with, it functions as a dispersion improver for carbon black, and also has an effect as an antioxidant, which improves aging resistance and is preferable in terms of reactivity with a lithium-terminated polymer. Compounds such as N, N-dialkylbenzene have no functional groups such as aldehydes and ketones, and therefore do not react with the conjugated diene-based polymer anion and thus have no effect.

〔Example〕

The present invention will be further described below with reference to examples. The content of the conjugated diene compound such as vinyl aromatic compound, isoprene and butadiene in the conjugated diene polymer of the present invention is 100 MH.
It was determined from z ¹ H-NMR (manufactured by JEOL Ltd.).

The microstructure of the polybutadiene part is D. It was determined by the method of Morero et al. (Chem.e Ind., Vol 41 p758: 1959).

The microstructure of the polyisoprene part was determined by 100 MHz ¹ H-NMR. The tensile properties of the vulcanized product were measured according to JIS K6301. The impact resilience was measured with a Dunlop trypsometer at 70 ° C., as an index of rolling friction resistance of the tire tread. Regarding the heat stability of the raw rubber, 100 g of the polymer was put into a glass test tube and heat aged at 90 ° C. in the air for 5 days, and the Mooney viscosity was measured.

Reference Example 16 Cyclohexane 2500 was added to the stainless reactor of 6.
g, 100 g of styrene, 390 g of 1,3-butadiene, and 22.5 g of tetrahydrofuran, and the temperature of the mixture was adjusted to 20 ° C., and then n-butyllithium 0.3
2 g was added and polymerization was carried out for 35 minutes at an elevated temperature. When the polymerization conversion rate reached 95% and 85 ° C, 1,
10 g of 3-butadiene was added and polymerization was continued for 10 minutes. 1/8 per mol of n-butyllithium in the reactor
Molar tin tetrachloride was added and the reaction was carried out for 15 minutes. Then, p-dimethylaminobenzaldehyde was added to the reactor in an amount of 1/2 mol per mol of n-butyllithium.
Reaction was performed for a minute. 2g of the polymer was added to the polymer solution.
After adding 6-di-tert-butyl-p-cresol, the solvent was removed by steam stripping, and the product was dried on a hot roll at 100 ° C. to obtain the product. The obtained polymer was kneaded and blended with a Bravegadder plast mill and a roll according to the formulation shown in Table 1 and vulcanized at 145 ° C. for 20 minutes. The characteristic values of the polymer and the properties of the vulcanizate are shown in Table 2.

Example 1 The procedure of Reference Example 1 was repeated except that p-dimethylaminoacetophenone was used instead of p-dimethylaminobenzaldehyde in Reference Example 1. The results are shown in Table 2.

Reference Example 2 In Reference Example 1, dibutyldichlorotin was used instead of tin tetrachloride.
The same procedure as in Reference Example 1 was performed except that 1/4 mol was used. The results are shown in Table 2.

Reference Example 3 In Reference Example 1, p-dimethylaminobenzaldehyde was added to n.
The same procedure as in Reference Example 1 was carried out except that 1/8 mol of butyllithium was used. The results are shown in Table 2.

Reference Example 4 The procedure of Reference Example 1 was repeated except that the amount of tetrahydrofuran was 7.0 g and the polymerization initiation temperature was 35 ° C. The results are shown in Table 2.

Reference Example 5 In Reference Example 1, 40 g was used instead of 390 g of 1,3-butadiene.
Polymerization was carried out using 0 g and without using post-added 1,3-butadiene. Others were performed in the same manner as in Reference Example 1.
The results are shown in Table 2.

Comparative Example 1 In Example 1, p-dimethylaminoacetophenone was added to n-
Example 1 was repeated except that 0.08 mol was used per 1 mol of butyllithium. The results are shown in Table 2.

Comparative Example 2 In Example 1, p-dimethylaminoacetophenone was added to n-
Example 1 was repeated except that 1.5 mol was used per 1 mol of butyllithium. The results are shown in Table 2.

Comparative Example 3 The procedure of Example 1 was repeated, except that 0.28 g of n-butyllithium and 1/40 mol of tin tetrachloride were used per 1 mol of n-butyllithium. The results are shown in Table 2.

Comparative Example 4 Example 1 was repeated except that dimethylaminobenzene was used instead of p-dimethylaminoacetophenone in Example 1. The results are shown in Table 2.

Example 26 2500 g of cyclohexane in a stainless steel reactor of 6,
1,3-Butadiene 500g Tetrahydrofuran 7.0
After charging g, these mixtures were adjusted to 35 ° C., 0.33 g of n-butyllithium was added, and polymerization was carried out for 30 minutes at an elevated temperature. The polymerization conversion rate was 100%. 1/8 mol of tin tetrachloride was added to 1 mol of n-butyllithium in the reactor, and 10 minutes later, 1/3 mol of p-dimethylaminoacetophenone was added to 1 mol of n-butyllithium.
Reaction was performed for a minute. Thereafter, the same procedure as in Example 1 was performed.

Vulcanization was performed at 145 ° C. for 30 minutes with the compounding recipe shown in Table 3. The results are shown in Table 4.

Example 3 In Example 2 without using tetrahydrofuran, 1,3-
The same procedure as in Example 2 was repeated except that isoprene was used instead of butadiene and the polymerization time was 1 hour. The fourth result
Shown in the table.

Comparative Example 5 The procedure of Example 2 was repeated, except that p-dimethylaminoacetophenone was not used in Example 2. The results are shown in Table 4.

Comparative Example 6 The procedure of Example 3 was repeated except that p-dimethylaminoacetophenone was not used. The results are shown in Table 4.

[Effects of the Invention] As is apparent from the above, according to the present invention, in producing a conjugated diene polymer containing a tin-carbon bond, after coupling with a tin halide compound, N, N-dialkylaminoacetophenone is further added. By reacting a compound, it is possible to obtain an unprecedented excellent tin-carbon bond-containing conjugated diene polymer in which thermal stability and storage stability are improved, and the vulcanized product has improved impact resilience and fracture strength. It is possible to provide a manufacturing method capable of

Claims (3)

[Claims] 1. A halogenated compound having a halogen atom equivalent of 0.2 to 1.0 equivalent per 1 gram atom equivalent of lithium after polymerizing a conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound using an organic lithium compound as an initiator in a hydrocarbon solvent. Reaction with a tin oxide compound, and 0.1-1.0 mol of the N, N-dialkylaminoacetophenone compound with respect to 1 gram atom equivalent of lithium.
A method for producing a conjugated diene polymer containing a carbon bond. 2. The method for producing a tin-carbon bond-containing conjugated diene polymer according to claim 1, wherein the conjugated diene compound is 1,3-butadiene and the vinyl aromatic compound is styrene. 3. The method for producing a tin-carbon bond-containing conjugated diene polymer according to claim 1, wherein the tin halide compound is bonded to the conjugated diene polymer by a tin-butadienyl bond.