JPH0228605B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a styrene-butadiene copolymer with improved rolling friction resistance and fracture properties. Conventionally, random styrene-butadiene copolymers have been obtained by polymerizing 1,3-butadiene and styrene using an organolithium compound in the presence of an ether compound or a tertiary amine compound in a hydrocarbon solvent. It is well known that A method of coupling a styrene-butadiene copolymer with a tin halide compound is also known (Japanese Patent Publication No. 4996/1983). However, although styrene-butadiene copolymers coupled by this method have improved fracture properties compared to copolymers that have not been coupled, they are not necessarily sufficient in improving rolling friction resistance properties. In order to improve these drawbacks, the inventors of the present invention made extensive studies and surprisingly found that these drawbacks were solved by adding a conjugated diene compound immediately before coupling to suppress the formation of bonded chains between styrene units and tin. discovered that it is possible to improve
This led to the present invention. In the present invention, 1,3-butadiene and styrene are polymerized using an organolithium compound in a hydrocarbon solvent in the presence of an ether compound or a tertiary amine compound, and then the general formula R _x So _{Z y} or R _a Z _{b So} (CH ₂ ) _{o So}
R _a Z _b [supported, in the formula R is an alkyl group, an alkenyl group,
cycloalkyl group or aromatic hydrocarbon group, Z is a halogen atom, x is an integer of 0 to 2, a is an integer of 0 to 2, n is an integer of 1 to 10, y is an integer of 2 to 4, b is 1 is an integer of ~3] When performing coupling with a tin compound represented by 3, a conjugated diene compound is added and polymerized immediately before coupling. A method for producing a polymer is provided. According to the present invention, it is possible to produce a random styrene-butadiene copolymer containing conjugated diene-tin bond chains that has improved rolling friction resistance properties and fracture properties. A polymer containing a conjugated diene monomer unit and a tin bond chain can also be obtained by adding a halogenated tin compound before the styrene-butadiene copolymerization reaction is completed, but with this method, unreacted monomer remains. This is not only economically disadvantageous, but also makes it difficult to obtain a polymer of stable quality because the styrene content in the styrene-butadiene copolymer changes depending on the timing of addition of the tin halide compound. It is clear from the following that the conventional coupled styrene-butadiene copolymer is a copolymer containing a styrene unit and a bonded chain of tin. In other words, even though the styrene-butadiene copolymer produced using an organolithium catalyst is essentially a random styrene-butadiene copolymer, a detailed look at such a copolymerization reaction shows that the copolymer produced is Although the styrene content in the polymer is lower than the styrene content in the monomer charge,
As the polymerization reaction progresses, the styrene content in the copolymer approaches the charged styrene content, and just before the end of polymerization, styrene is rapidly incorporated into the copolymer.
At the end of polymerization, the copolymerized styrene content and the charged styrene content match [TA Antokowiak et al., J.
Polymer & ci., part A-1Vol10, 1319
(1972)]. The behavior of such a copolymerization reaction can also be easily determined by observing the hue of the polymerization system. In other words, the hue of the polymerized system is yellow when the living polymer end is polybutadiene lithium until just before the end of polymerization, but when the polymerization is over, the color of the living polymer end changes from red to yellowish red of polystyryllithium. Can be done. The present invention will be explained in detail below. Examples of the organic lithium compounds used in the present invention include methyllithium, ethyllithium, propyllithium, butyllithium, pentyllithium, octyllithium, 1,4-dilithiobutane, 1,5-dilithiopentane, and 1,10-dilithiodecane. It will be done. The amount of these organolithium compounds used is 0.2 to 100 grams of monomer.
In the range of 20 mmol. Examples of ether compounds that can be used include diethyl ether, dibutyl ether, tetrahydrofuran, 2-methoxytetrahydrofuran, 2-methoxymethyltetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether,
Examples include diethylene glycol diethyl ether, diethylene glycol dibutyl ether, and triethylene glycol dimethyl ether.
Furthermore, examples of tertiary amine compounds include triethylamine, tripropylamine, pyridine,
NNN′N′-tetramethylethylenediamine,
NNN′N′-Tetraethylethylenediamine, N
- Examples include methylmorpholine. The amount of the ether compound and the tertiary amine compound used is in the range of 0.05 to 1000 mol per mol of the organolithium compound. The styrene content in the monomer mixture in the copolymerization reaction of 1,3-butadiene and styrene is 3
-40% by weight, preferably 5-30% by weight. Furthermore, by the method of the present invention, a polymer having a vinyl content of 20 to 95% in the polybutadiene portion can be obtained. Polymerization is carried out at a temperature range of -20°C to 150°C.
A particularly preferred embodiment of the polymerization is that the polymerization is initiated at a temperature of -20°C to 60°C and continued at an elevated temperature where the difference between the maximum temperature reached and the polymerization initiation temperature is 30°C to 120°C. The polymerization solvent may be one or more of aliphatic hydrocarbon solvents such as butane, pentane, hexane, heptane, and octane, alicyclic hydrocarbon solvents such as cyclohexane and methylcyclopentane, and aromatic hydrocarbon solvents such as benzene, xylene, and toluene. A mixture of two or more types is used. Furthermore, a _C4 fraction from which polymerization inhibitors have been removed is also used. The amount of solvent is 0.5 to 1 part by weight of monomer.
It is used in a range of 20 parts by weight. The conjugated diene compound added prior to coupling with a tin halide compound in the present invention is preferably added to the polymerization system after all of the styrene monomer is consumed in the copolymerization of 1,3-butadiene and styrene. Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 1
-phenylbutadiene and the like, preferably 1,3-butadiene, isoprene, 1,3-pentadiene and the like. The amount of conjugated diene compound is 1 organolithium compound
Range of 0.5 to 200 moles, preferably 1 to 200 moles
Used in a range of 50 moles. If the amount is less than 0.5 mol, the object of the present invention cannot be achieved, while if it exceeds 200 mol, the terminal of the polymer may be deactivated by impurities contained in the conjugated diene compound, which is not preferable. The temperature when adding the conjugated diene compound is 0~
A temperature in the range of 150° C. is preferably used at the end of the polymerization. In the present invention, the tin halide compound used for coupling has the general formula R _{x So} Z _y or R _a Z _{b So} (CH ₂ ) _{o So} R _a Z _b (wherein R: alkyl group, alkenyl group, cycloalkyl group, aromatic group, Z: halogen atom x: integer of 0 to 2, a: integer of 0 to 2, n: integer of 1 to 10, y: integer of 2 to 4, b: 1 to
The tin halide compounds represented by the integer 3) include, for example, methyltrichlorotin, dimethyldichlorotin, tetrachlorotin, dichlorotin, ethyltrichlorotin, diethyldichlorotin, tetrafluorotin, butyltrichlorotin, and dibutyldichlorotin. Tin, octyltrichlorotin, dioctyldichlorotin, methyltribromtin, dimethyldibromtin, octyltribromtin,
Tetrabromtin, tetraiodotin, cyclohexyltrichlorotin, phenyltrichlorotin, 1,2 bis(trichlorostannyl)ethane,
1,2 bis(methyldichlorostannyl)ethane,
1,4 bis(trichlorostannyl)butane, 1,
4bis(methyldichlorostannyl)butane and the like are used. The coupling reaction using the tin halide compound is carried out at 0 to 150°C for 0.5 minutes to 20 hours. The amount of the tin halide compound added is in the range of 0.1 to 3.0 equivalents, preferably 0.2 to 1.5 equivalents based on the halogen atom of the tin halide compound, per 1 atomic equivalent of lithium in the organolithium compound. The proportion of the polymer having conjugated diene-tin bonds can be controlled by the amount. less than 0.1 equivalent, or
If the amount exceeds 3.0 equivalents, the proportion of the polymer containing a conjugated diene-tin bond chain will be small, making it impossible to obtain a polymer with excellent rolling friction resistance properties and fracture properties, which are the objectives of the present invention. The polymerization and coupling reactions of the present invention are carried out under an inert gas atmosphere such as nitrogen or argon. The styrene-butadiene copolymer of the present invention can also be obtained by batch polymerization or continuous polymerization using a tank reactor, tower reactor, tube reactor, or the like. The molecular weight distribution of the polymer depends on the type of coupling agent,
Not only the amount but also the polymerization method can be freely controlled. According to the method of the present invention, the bound styrene content is 3 to 40
Weight%, vinyl content of polybutadiene part 20-95
A random styrene-butadiene copolymer containing at least 10% or more, preferably 20% or more of a polymer having a conjugated diene unit-tin bond chain and having a Mooney viscosity (ML100°C 1+4) of 10 to 150% can be easily obtained. In the present invention, the proportion of the polymer having a conjugated diene unit-tin bond chain is measured by gel permeation chromatography (GPC), and is determined from the bimodal or polymodal molecular weight distribution.
Calculated using formula (1). Proportion (%) of polymer having conjugated diene unit-tin bonds = (1 - peak area of lowest molecular weight portion/overall peak area) x 100... (1) The amount of bound styrene is 699cm in the infrared absorption spectrum
It was determined from a calibration curve using ^-1 . The microstructure of the polybutadiene moiety was determined using the method of D.Moreo et al.
Obtained according to Ind Vol 41 758 (1959). Repulsion elasticity at 70°C was used as an index of rolling friction resistance characteristics. The higher the rebound resilience at 70°C, the lower the energy loss due to rolling friction and the better the rolling friction resistance characteristics. Example 1 Cyclohexane was added to a stainless steel reactor of 5.
2.25Kg, styrene 125g, 1,3-butadiene 370
After adjusting the temperature of the mixture to 50°C, 0.32g of n-butyllithium was added and polymerization was carried out isothermally at 50°C. The polymerization conversion rate reached 100% 35 minutes after the start of polymerization, but the color of the polymer solution was red to yellow-red due to styryl terminals. 1,3-butadiene in polymer solution
Immediately after adding 5.0 g, the color of the polymer solution changed to yellow. After 5 minutes, add 0.196g of tetrachlorotin,
The coupling reaction was carried out at 40°C for 30 minutes. The polymer was obtained by adding 3 g of 2,6-ditertiary-butyl-p-cresol to the polymer solution, removing the solvent by steam stripping, and drying with a hot roll at 100°C. The characteristic values of the polymer are shown in Table 1. According to the formulation shown in Table 3, knead and blend using a Brabender plasto mill and roll at 145℃35.
Vulcanization was carried out for a minute. The properties of the vulcanizate are shown in Table 1. Example 2 Except for using 0.375 g of methyltribrom tin in place of 0.196 g of tetrachlorotin in Example 1,
The same procedure as in Example 1 was carried out. The results are shown in Table 1. Example 3 In Example 1, 1,4 bis(trichlorostannyl)butane was used instead of 0.196 g of tetrachlorotin.
The same procedure as in Example 1 was carried out except that 0.254 g was used. The results are shown in Table 1. Example 4 Example 1 except that 5.0 g of isoprene was used instead of the 5.0 g of 1,3-butadiene added in Example 1.
I did the same thing. The results are shown in Table 1. Example 5 Same as Example 1, 1,3-butadiene 450g, styrene 50g, tetrahydrofuran 20g, polymerization temperature 40
The same procedure as in Example 1 was carried out except that the temperature was 0.degree. The results are shown in Table 1. Example 6 The same procedure as in Example 1 was carried out except that 0.098 g of tetrachlorotin was used instead of 0.196 g. The results are shown in Table 1. Example 7 Cyclohexane 25 in a 50 stainless steel reactor
Kg, styrene 1.25Kg, 1,3-butadiene 3.75
After charging 70 g of tetrahydrofuran and adjusting the temperature of the mixture to 35° C., 3.25 g of n-butyllithium was added to initiate polymerization. The maximum polymerization temperature reached 96° C. 20 minutes after the start of polymerization, and the color of the polymer solution was red to yellow-red due to styryllithium terminals, but after another 10 minutes, it changed to yellow due to butadienyllithium terminals. The polymerization conversion rate was 100%. After 50 g of 1,3-butadiene was added to the polymer solution, 2.25 g of tetrachlorotin was added 1 minute later.
The coupling reaction was carried out at ℃ for 15 minutes. The polymer was obtained by adding 30 g of 2,6-ditertiary-butyl-p-cresol to the polymer solution, removing the solution, and drying. A vulcanizate was obtained by blending and kneading in the same manner as in Example 1. The results are shown in Table 1. Example 9 25 kg of cyclohexane and styrene in a 50 reactor
0.85Kg, 1,3-butadiene 4.15Kg, and tetrahydrofuran 30g were charged and the temperature of the mixture was 35℃.
After adjusting the temperature, 3.70 g of n-butyllithium was added to initiate polymerization. Polymerization temperature reached 26 minutes after the start of polymerization.
The temperature reached 92°C and the polymer conversion rate was 94%. After adding 250 g of 1,3-butadiene to the polymer solution, 2.25 g of tetrachlorotin was added 30 seconds later.
The coupling reaction was carried out at ℃ for 15 minutes. The polymer was obtained by adding 30 g of 2,6-ditertiary-butyl-p-cresol to the polymer solution, followed by drying to remove the solution. A vulcanizate was obtained by blending and kneading in the same manner as in Example 1. The results are shown in Table 2. Example 10 In place of 20g of tetrahydrofuran in Example 5
NNN′N′-Tetramethylethylenediamine 1.16g
Example 1 except that 0.61 g of dibutyldichlorotin was used instead of 0.196 g of tetrachlorotin.
I did the same thing. The results are shown in Table 2. Comparative Example 1 The same procedure as in Example 1 was carried out except that 5.0 g of 1,3-butadiene was not newly added after the completion of the polymerization in Example 1. The results are shown in Table 1. Comparative example 2 1,3-butadiene after completion of polymerization in Example 1
The same procedure as in Example 1 was carried out except that 0.08 g (butadiene/n-butyllithium molar ratio 0.3) was used instead of 5.0 g. The results are shown in Table 1. Comparative Example 3 In place of 0.32g of n-butylurium in Example 1
Polymerization was carried out using 0.27 g. The polymer was subjected to no coupling reaction, but the solvent was removed and dried to obtain a vulcanizate in the same manner as in Example 1. The results are shown in Table 1.

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[Table] * Percentage of polymers containing styrene units and tin bond chains

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【table】

【table】

[Table] Azylsulfenamide

Claims (1)

[Claims] 1. After polymerizing 1,3-butadiene and styrene using an organolithium compound in a hydrocarbon solvent in the presence of an ether compound or a tertiary amine compound, the general formula R _x SnZ _y or R _a Z _b Sn(CH ₂ ) _o SnR _a Z _b [wherein R is an alkyl group, an alkenyl group,
cycloalkyl group or aromatic hydrocarbon group, Z is a halogen atom, x is an integer of 0 to 2, a is an integer of 0 to 2, n is an integer of 1 to 10, y is an integer of 2 to 4, b is 1 is an integer of ~3] Styrene-butadiene containing a conjugated diene unit-tin bond chain, characterized in that when coupling with a tin compound represented by the following, a conjugated diene compound is added and polymerized immediately before coupling. Method for producing copolymer. 2. The styrene according to claim 1, wherein the conjugated diene compound is selected from 1,3-butadiene, isoprene and 1,3-pentadiene.
A method for producing a butadiene copolymer.