JPS6243439A - Random styrene-butadiene copolymer composition - Google Patents

Abstract

PURPOSE:A random styrene-butadiene copolymer composition, consisting of a straight-chain component modified with a specific amide compound and a branched component modified with a specific polyfunctional coupling agent and having a specific styrene chain distribution. CONSTITUTION:A composition, consisting of (A) 20-80wt% straight-chain component obtained by reacting a lithium-terminated copolymer prepared by copolymerizing styrene with butadiene in the presence of an organolithium compound as a polymerization initiator in a hydrocarbon solvent with an amide compound expressed by the formula (R1 is 1-6C alkyl, cycloalkyl or alkoxyalkyl; Y is oxygen or sulfur; n is an integer 3 or 4) (the polymethylene chain may be substituted by 1-6C alkyl group) and (B) 8-20wt% branched component obtained by reacting the lithium-terminated polymer (A) with a coupling agent having >=3 reactive sites and having 5-45wt% combined styrene and >=40wt% thereof being styrene chain, containing <=5wt% long chain having >=8 styrene units and having 30-150 Mooney viscosity.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a linear component modified with a specific amide compound and a branched chain component modified with a polyfunctional coupling agent having at least three reactive sites. The present invention relates to a random styrene-butadiene copolymer composition comprising styrene units in the copolymer chain having a specific styrene chain distribution.

[Prior Art] Random styrene-butadiene copolymers have traditionally been widely used as rubber for tires, but in recent years, with the demand for lower fuel consumption and improved driving safety for automobiles, they have become less effective in terms of tire properties. There is a growing demand for tires with excellent fuel efficiency and handling stability, and tire rubbers are required to have high rebound resilience to improve fuel efficiency and high wet skid resistance to improve handling stability. There is. Furthermore, workability such as roll workability and extrusion workability, which are important in tire manufacturing, is required.

However, the relationship between impact resilience and wet skid resistance is contradictory, and various methods have been proposed to balance these contradictory properties and improve processability. Method of setting rubber (JP-A No. 57-1213807), method of blending a high molecular layer rubber having a specific glass transition temperature and a low molecular weight rubber (JP-A No. 57-180846), tin and a cup excluding tin A method of introducing a specific amount of branched components bonded by a ring agent (Japanese Unexamined Patent Publication No. 59-45338), a method of highly uniformizing the styrene center in a copolymer chain with bimortal molecular weight distribution (Special Gansho 59-1
No. 59123) There is a hat. In addition, as a method to improve only the processability, a method in which a branched polymer is immersed (Japanese Patent Publication No. 44-
No. 4998, Special Publication No. 1983-36957, Special Publication No. 1983-
No. 52684).

- - A method of introducing a specific functional group into a diene polymer as a method of improving impact resilience without impairing wet skid resistance (JP-A-58-182804, JP-A-80-137813) No.) has been proposed.

[Problems to be Solved by the Invention] However, although these methods have shown improvement effects to some extent, they have not yet been able to satisfy these contradictory characteristics to a high degree and to improve processability.

The present invention was made in view of the above points, and an object of the present invention is to provide a random styrene-butadiene copolymer composition that has a significantly improved balance between impact resilience and wet skid resistance, and has improved processability. .

[Means and effects for solving the problems] The present invention has been made based on intensive studies on the chain distribution of styrene units in a styrene-butadiene copolymer chain in which a functional group is bonded. Consisting of a linear component modified with an amide compound and a branched component modified with a polyfunctional coupling agent having at least three reactive sites, the styrene units in the copolymer chain are linked to specific styrene chains. This was based on the discovery that a random styrene-butadiene copolymer composition having a distribution has an extremely excellent balance between impact resilience and wet skid resistance, and has excellent processability.

That is, the present invention uses a lithium-terminated copolymer obtained by copolymerizing styrene and butadiene in a hydrocarbon solvent using an organolithium compound as a polymerization initiator, and a lithium-terminated copolymer obtained by the general formula group, cycloalkyl group, or alkoxyalkyl group, Y represents an oxygen atom or a sulfur atom, and n represents an integer of 3 to 4) or +C in the above general formula
A linear component obtained by reacting an amide compound in which one hydrogen atom of the polymethylene chain represented by khh is substituted with a C1 to C6 alkyl group, and a thiium-terminated copolymer described in A styrene-butadiene copolymer having a Mooney viscosity (ML+, 4.100°C) of 30 to 150, consisting of a branched component obtained by reacting a polyfunctional coupling agent having a reactive site, in which bound styrene is 5 to 45% by weight, 40% by weight or more of the combined styrene with a single styrene chain with one styrene unit, 5% by weight or less of the combined styrene with a long styrene chain with 8 or more styrene units, linear components 20-80 tons 1% of copolymer
and relates to a random styrene-butadiene copolymer composition characterized in that the remaining branched component is 80 to 20% by weight.

The random styrene-butadiene copolymer composition of the present invention exhibits excellent vulcanizate properties and processability, and is used for various rubber applications, and is useful for tire applications such as treads and sidewalls.

The present invention will be explained in detail below.

The amide compound used in the present invention has a specific hydrocarbon group bonded to the nitrogen atom, and the nitrogen atom and the carbon
A general formula bonded by polymethylene chains represented by fn (wherein, R1 is a C1 to C6 alkyl group, cycloalkyl group, or alkoxyalkyl group, Y is an oxygen atom or a sulfur atom, and n is an integer of 3 to 4) It is necessary to have a cyclic structure of a 5n ring or a 6-membered ring represented by the following. This has an extremely important meaning in achieving the present invention. Usually, in the stoichiometric reaction of an amide compound having an acyclic structure and a lithium-terminated polymer, it is described in Japanese Patent Publication No. 42-24174. As shown in the figure, the bond between the carbonyl group and the 7-mino group is broken, and the 7-mino group cannot be effectively introduced into the conjugated diene polymer. This reaction is not preferred in practical use because it results in a secondary amine that inactivates the compound.

The above reaction is shown below (in the formula, P represents a polymer chain).

- On the other hand, in the stoichiometric reaction of the amide compound having a dotted structure used in the present invention and the lithium-terminated polymer in a hydrocarbon solvent, the secondary amine is not liberated and functional groups such as amine groups are removed. group can be reliably introduced. In this way, the conjugated diene polymer composition having a linear component made by the reaction of an amide compound with a cyclic structure and a lithium-terminated polymer is kneaded, mixed, and vulcanized with compounding agents such as carbon black and process oil. The vulcanizate exhibits excellent impact resilience and abrasion resistance.

20 to 80% by weight of the conjugated diene polymer composition of the present invention is a linear component modified with a specific amide compound, and the remaining 80 to 20% by weight contains at least three reactive sites. It is a branched component that is branched by a polyfunctional coupling agent having a polyfunctional coupling agent. The linear component is less than 20% by weight, or the branched component is 801J! If the content exceeds 80% by weight, or if the content of the branched component exceeds 20% by weight, the processability decreases, which is not preferable.

The bound styrene content of the copolymers of the present invention is from 5 to 45% by weight, preferably from 10 to 40% by weight. If the bound styrene content is less than 5% by weight, the wet skid resistance will decrease, which is undesirable. On the other hand, if the bound styrene content exceeds 45% by weight, the impact resilience and abrasion resistance will decrease, which is undesirable.

The copolymer of the present invention has a styrene medium velocity jO (hereinafter referred to as S1) having one styrene unit of 40% by weight or more of the bound styrene, preferably 55ff! Q% or more, and a long styrene chain consisting of 8 styrene units (hereinafter referred to as S8~) is the bonded styrene 5. Ol 3% or less, preferably 2.
It must be less than 5% by weight. Even if S+ is less than 40% by weight of the bonded styrene, even if 58~ exceeds 5% by weight of Tfi, it is undesirable because impact resilience, abrasion resistance, and wet skid resistance deteriorate. .

Mooney viscosity (ML+, 4°100
C) is 30-150, preferably 50-120.

If the Mooney viscosity is less than 30, the effects of improving impact resilience and abrasion resistance will not be sufficient; if the Mooney viscosity exceeds 150, problems will remain in the calendering processability and extrusion processability of the compound.

The physical properties of the copolymer of the present invention change significantly by changing the microstructure of the butadiene moiety, and the physical properties also change greatly depending on the styrene composition distribution in the copolymer chain.

Regarding the relationship between the microstructure and physical properties of the butadiene moiety, the relationship between the 1.2 vinyl content and the physical properties is known. For example, as the l,2 vinyl content increases, the wet skid resistance of the polymer improves; Abrasion resistance decreases [rubber
Age (Rubber Age) VoR104,55 (
1972)).

Furthermore, as the 1,2-vinyl content increases, heat resistance and reversion are improved, H. Nordsiek.

r 1979 Report to the International Rubber Conference J (Pape
rPresented to the Int, Ru
bber Conf, +979).

The relationship between the 1.2 vinyl content and physical properties is already known, and in the present invention, the 1.2 vinyl content is not particularly limited, but from the viewpoint of impact resilience and abrasion resistance, the 1.2 vinyl content is On the other hand, from the viewpoint of wet skid resistance, the 1.2 vinyl content is preferably 30 to 90%. In any case, the 1.2 vinyl content should be determined depending on the purpose of use.

Furthermore, even if the distribution of 1 and 2 vinyl in the polymer chain is uniform in the polymer chain.

In addition, as shown in Japanese Patent Publication No. 48-875, it may change gradually along the polymer chain, or it may be distributed in blocks (asp~33018
40) In short, it is best to decide depending on the purpose of use.

Furthermore, regarding the styrene composition distribution in the styrene-butadiene copolymer chain, it may be uniformly distributed in the copolymer chain, or it may be non-uniformly distributed in the copolymer chain (Japanese Patent Application No. 80
-4108), and should be determined depending on the purpose of use.

The copolymer of the present invention has a well-known relationship between the molecular weight distribution and the processability, in which the processability changes significantly by changing the molecular weight distribution. The molecular l1 distribution (Mv /MN) expressed as the ratio to the molecule ffi (Ms) is not particularly limited, but considering the balance between physical properties and processability, it is 1
．． 2 to 3.5 is preferable, and the weight average molecular weight (M 11
) and number average molecular weight (FaN') (Mw'/Fa
x') is also not particularly limited, but 1.1
~2.5 is 1 minute.

The copolymer of the present invention is produced by the method described below. One method is to copolymerize styrene and 1,3-butadiene in a hydrocarbon solvent using an organolithium compound as an initiator, as described in British Patent No. 99472Ei and Japanese Patent Application Laid-open No. 59-14.
As described in No. 0211 and JP-A-56-143209, the styrene monomer content in the monomer composition ratio of styrene and 1,3-butadiene in the polymerization system is adjusted to be within a specific concentration range. butadiene or 1
．． A lithium-terminated copolymer obtained by carrying out copolymerization by continuously or intermittently supplying a mixture of 3-butadiene and styrene, and a lithium-terminated copolymer obtained by the general formula (wherein R1 is a C1 to C6 alkyl group, cycloalkyl group or alkoxyalkyl group, Y represents an oxygen atom or a sulfur atom, and n represents an integer of 3 to 4) or 1c in the above general formula
Adding an amide compound in which one or more of the hydrogen atoms of the polymethylene chain represented by Hz"rn is substituted with a C1 to C6 alkyl group and a polyfunctional coupling agent having at least three reactive sites in a predetermined ratio. It can be obtained by

Another method is to copolymerize styrene and 1,3-butadiene in a hydrocarbon solvent using an organolithium compound as an initiator, and styrene is copolymerized at a rate slower than the copolymerization rate, as described in Japanese Patent Publication No. 38-23i34. and 1,3-butadiene to carry out copolymerization, and the obtained lithium-terminated copolymer and the general formula
is an alkyl group, dichlorofurkyl group or alkoxyalkyl group, Y is an oxygen layer f or a sulfur atom, and n is 3 to 4
(representing an integer of ) or fC in the above general formula
l (adding an amide compound in which one or more of the hydrogen atoms of the polymethylene chain represented by 2jn is substituted with a Ct-C6 argyl group and a polyfunctional coupling agent having at least three reactive sites in a predetermined ratio) It can be obtained by

When the amide compound and polyfunctional camping agent used in the present invention come into contact with the lithium-terminated polymer, they react almost instantaneously and quantitatively. Therefore, in order to obtain the copolymer of the present invention, the amounts of the amide compound and the polyfunctional coupling agent to be added are 0.00000000000000000000000000000000000000000000000000000,000,0000,0000,0000,00000,0000,00000,00000,0000,000000,00000 which the equivalent ratio of the amide compound and the polyfunctional coupling agent to 1 mole of the organolithium compound. 20-0
．． 80.

0.80 to 0.20, and the total equivalent ratio of m to approximately 1, and after the completion of Jli polymerization, the amide compound and the polyfunctional coupling agent are added simultaneously or separately. It may be added to the polymerization system, or after the completion of polymerization, 1,3-butadiene may be added, and then the amide compound and the polyfunctional coupling agent may be added.

Alternatively, a polyfunctional coupling agent may be added during the copolymerization, and an amide compound may be added after the polymerization is completed.

In addition, the copolymer composition of the present invention comprises a linear component obtained by reacting a lithium-terminated copolymer with a special amide compound, a lithium-terminated copolymer, and a polymeric composition having at least three reactive sites. The branched components obtained by reacting the functional coupling agent are prepared separately, and these copolymers are mixed with a linear component of 20 to 80% by weight and a branched component of 80 to 20% by weight.
% by weight.

In the copolymer composition of the present invention, the balance between physical properties and processability is changed by changing the intrinsic viscosity ratio between the branched component and the linear component in the copolymer. The relationship between the intrinsic viscosity and processability of these branched components and linear components is already known (Japanese Patent Publication No. 59-528G4), and in the present invention, the above-mentioned intrinsic viscosity ratio is not particularly limited, but the relationship between processability and Physical properties 7~
Considering the lance, 1.5 to 5.5 is preferable.

In the present invention, in order to adjust the microstructure of the butadiene moiety in the copolymer chain or the randomness in the copolymer chain of styrene and butadiene, ethers, tertiary amines, and alkali totally bent alkoxides are used. For example, diethyl ether, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, etc. can be used.
Di-n-butyl ether, ethylene glycol n-butyl-tert-butyl ether, ethylene glycol di-tert-butyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetrahydrofuran, α-methoxymethyltetrahydrofuran, dioxane, 1.2- Dimethoxybenzene, triethylamine, N, N, N', N'-
Tetramethylethylenediamine, potassium-tert-
7-myl oxide, potassium-tert-butyl oxide, and the like. These compounds may be used alone or as a mixture of two or more.

The amount of the polar compound used in the present invention is 0 to 200 mol per mol of the organic lithium compound.

Thu) As the organic lithium compound used for A Ming, n
-Propyllithium, isopropyllithium, n-butyllithium, 5ec-butyllithium.

Monoorganolithium compounds such as tart-butyllithium, dilithiomethane,! , 4-dirithiobutane, 1.4-
These include polyfunctional organolithium compounds such as dilithio-2-ethylcyclohexane, 1,2-dilithio-1,2-diphenylmethane, and 1.3.5-)lilithiobenzene.

These may be used alone or in a mixture of two or more. Furthermore, as the polyfunctional organolithium compound used in the present invention, compounds that can be substantially converted into a polyfunctional organolithium compound by reacting the above-mentioned monoorganolithium compound with another compound may also be used. For example, the reaction product of a monoorganolithium compound and a polyvinyl aromatic compound (Japanese Patent Publication No. 55-6852), the reaction product of a monoorganolithium compound with a conjugated diene, and/or a monovinyl aromatic compound, A reaction product obtained by reacting a group compound, or a reaction product obtained by simultaneously reacting a monoorganolithium compound, a conjugated diene, and/or a monovinyl aromatic compound, and a polyvinyl compound (West German Patent No. 2003384, etc.).

The amount of these organic lithium compounds used is usually 0.1 to 10 mmol per 100 g of conjugated diene thread yarn.

As hydrocarbon solvents used in the present invention, aliphatic, cycloaliphatic and aromatic hydrocarbons can be used9 For example, hydrocarbon solvents include propane, isobutane, n
-hexane, isooctane, cyclopentane, cyclohexane, benzene, toluene, etc., and particularly preferred solvents are n-hexane, cyclohexane, and benzene.

These may be used alone or as a mixture of two or more.

The amide compound used in the present invention has the general formula (wherein R1
represents a C1 to C6 alkyl group, cycloalkyl group or alkoxyalkyl group, Y represents an oxygen atom or a sulfur vt atom, and n represents an integer of 3 to 4) or fcH2sn in the above general formula One or more of the hydrogen atoms I of the polymethylene chain shown is C
Amide compounds substituted with 1 to C6 alkyl groups, specific examples include l-cyclohexyl-2-pyrrolidone, l-methyl-2-pyrrolidone, l-ethyl-2-pyrrolidone, l-propyl-2 -pyrrolidone, l-butyl-2-pyrrolidone, l-isopropyl-2-pyrrolidone, l,5-dimethyl-2-pyrrolidone, l-methoxymethyl-2-pyrrolidone, 1-methyl-2-piperidone,
1.4-dimethyl-2-piperidone, 1-ethyl-2-
piperidone, l-isopropyl-2-piperidone, l-
Examples include inpropyl-5,5-dimethyl-2-piperidone, and l-methyl-2-pyrrolidone and 1-methyl-2-piperidone are preferred, with l-methyl-2-pyrrolidone being particularly preferred.

The reaction temperature and reaction time between these amide compounds and the lithium-terminated copolymer can be adjusted over a wide range, but usually the reaction temperature is 25 to 125°C and the reaction time is within the range of 1 second to 3 hours.

The polyfunctional coupling agent used in the present invention includes:
Epoxidized soybean oil, epoxidized linseed oil, epoxidized liquid polybutadiene, dimethyl terephthalate, diethyl terephthalate, dimethyl phthalate, dimethyl isophthalate, diethyl adipate, terephthalic acid dichloride, phthalic acid dichloride, isophthalic acid dichloride, adipic acid dichloride , silicon tetrachloride, methyltrichlorosilane, hexachlorosilane, tetramethoxysilane,
Carbon tetrachloride, stannous chloride, methyltrichlorotin, stannous bromide, dodecyltrichlorotin, hexa-(2-
methyl-1-aziridinyl) triphosphatriazine,
Examples include pyromellitic dianhydride and polyaryl polyisocyanate. Among these, silicon tetrachloride, phthalic acid dichloride, +1! It is stannic oxide. When a copolymer with a branched component coupled with stannic chloride is kneaded with carbon black and process oil, the vulcanizate exhibits excellent impact resilience;
Copolymers with branched components coupled with silicon tetrachloride exhibit excellent processability, especially excellent extrusion properties.
Therefore, in order to obtain a copolymer with better processability, it is preferable to use silicon tetrachloride as a coupling agent.

The polymerization method in the present invention may be either a batch polymerization method or a continuous polymerization method. The centering temperature is in the range of 20 to 130 °C, and in batch polymerization, polymerization starts at 30 to 87 °C, and it is recommended to carry out the polymerization at an elevated temperature so that the maximum temperature reaches 90 to 125 °C. .

After the completion of the specified reaction, 2,6-di-tert-butyl-p-
After adding an antioxidant such as Fresol, the resulting polymer is subjected to conventional post-treatments such as separation, washing, and drying to obtain the desired copolymer.

The copolymer of the present invention is mixed with a process oil in a solution state,
After mixing, the solvent may be removed and used as an oil-extended rubber.

The copolymers of the present invention can be used alone or in blends with natural rubber or other synthetic rubbers such as polybutadiene, polyisoprene, emulsion polymerized styrene-butadiene copolymers, and the like. When used in a blend with natural rubber or other synthetic rubber, the copolymer of the present invention must account for at least 30% by weight of the raw rubber in order to exhibit the excellent properties of the present invention.

Further, the copolymer of the present invention is blended with known compounding agents such as carbon black, process oil, etc., and after mixing and vulcanization,
As a product, for example, tire applications such as tire tread, carcass, side wall shade, or extrusion products, automatic + l (
It can be used for applications such as window frames, industrial products, and anti-vibration rubber, but it has an excellent balance of impact resilience and weft skid resistance, as well as excellent processability, so it can be used particularly as a tread for fuel-efficient tires. .

[Examples] The present invention will be explained below with reference to Examples, but these Examples do not limit the present invention.

Note that measurements of various characteristics were carried out using the following methods.

The styrene chain distribution of random styrene-butadiene copolymers is analyzed with a method recently developed by Naka et al. Specifically, the styrene chain distribution is analyzed by gel permeation chromatogram (CPC) of the decomposed product obtained by ozone cleavage of all the double bonds of the butadiene unit (Proceedings of the Society of Polymer Science and Technology, Vol. 29, 9). No. 2055 page)
The proportion of branched components in the copolymer is calculated from the peak area on the high molecular weight side by GPC.

Further, the proportion of linear components in the copolymer is calculated from the difference between the total peak area of the copolymer and the peak area on the high molecular weight side by GPC. Mooney viscosity was measured in the usual manner using an L rotor at 100°C. The bound styrene was calculated from the absorption based on phenyl groups at 262 nm using ultraviolet absorption spectroscopy. The microstructure of the butadiene moiety was measured using an infrared spectrophotometer, and the zero impact resilience calculated by the Hampton method was measured using a Dunlop trypsometer at a test temperature of 70°C. Abrasion resistance was measured using a Pico abrasion tester. Wet skid resistance was measured using a device manufactured by the British Road Research Institute. Processability was judged based on the Mooney viscosity of the compound or the roll windability of the compound. The roll windability of the carbon blend was evaluated using a 6-inch roll based on the windability of the carbon blend, operability, etc.

Examples 1 to 3, Comparative Example 1.2 Under a nitrogen atmosphere, 8.2 kg of cyclohexane, 24 g of tetrahydrofuran, 0.30 kg of styrene, and 0.42 kg of 1,3-butadiene were placed in a stainless steel polymerization vessel with a capacity of about 10 cm and equipped with a stirrer. After adjusting the temperature of the mixture to about 70°C while stirring the mixture in the polymerization vessel vigorously, copolymerization was started by adding a predetermined amount of n-butyllithium as shown in Table 1. The temperature inside the 0m combiner is 1:
When the polymerization conversion rate of the copolymer finally obtained reaches approximately 25% by weight, the remaining 1,3-butadiene 0.
28 kg was added to the polymerization system at a constant rate for 10 minutes using a metering pump. ! Continuously supplied. The maximum temperature (approximately 88
℃) and the copolymerization is completed, a predetermined amount of stannic chloride is added as shown in Table 1, and then a predetermined amount of 1-
Methyl-2-pyrrolidone was added and reacted for about 10 minutes. 5 g of 2,6-tert-butyl-p-cresol was added to the copolymer solution thus obtained as a stabilizer.
was added and the solvent was removed by heating to obtain a copolymer. The thus obtained copolymer was mixed according to the formulation shown in Table 2.

The unvulcanized rubber composition obtained by cross-mixing in a Banbury mixer was vulcanized at 145° C., and the physical properties were evaluated. The measurement results are shown in Table-1.

Table 2 1) 74-Cyclohexyl-2-benzothiazylsulfenamide 71 N-isopropyl-N'-phenyl-p-phenylenediamine Examples 4-8. Comparative Examples 3 to 7 Table 1 was placed in a polymerization vessel similar to that used in Example 1 under a nitrogen atmosphere.
As shown in step 3, predetermined amounts of cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene (hereinafter referred to as primary butadiene) are charged, and the temperature of this mixture is adjusted to a predetermined temperature while vigorously stirring the mixture in the mixing vessel. After that, a predetermined amount of n-butyllithium was added as shown in Table 3 to start copolymerization. Next, as shown in Table 3, the remaining 1,3-butadiene (hereinafter referred to as secondary butadiene) was started to be continuously supplied to the polymerization system at a constant rate using a metering pump. After the supply of secondary butadiene is finished and the polymerization temperature reaches the maximum temperature to complete the copolymerization, a predetermined amount of stannic chloride is added as shown in Table 3, and then
3, a predetermined amount of the amide compound was added and reacted for about 10 minutes. However, in Comparative Example 5, the amide compound was changed to 1 g of methanol and copolymerization was carried out. To the thus obtained copolymer solution, 5 g of 2,6-sheet tert-p-cresol was added as a stabilizer, and the solvent was removed by heating to obtain a copolymer. The basic properties of the copolymer thus obtained are shown in Table 4. Table 2 shows these copolymers.
An unvulcanized rubber composition obtained by kneading and mixing in a Banbury mixer according to the formulation was vulcanized at 145° C., and physical properties were evaluated. The measurement results are shown in Table-4.

Comparative Examples 8 and 9 Under a nitrogen atmosphere, the same polymer as used in Example 1 was heated.
As shown in 3, predetermined amounts of cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were charged, and the temperature inside the centering vessel was adjusted to a predetermined temperature. After adding a predetermined amount of n-butyllithium to start copolymerization, a predetermined amount of stannic chloride was added as shown in Table 3, and then a predetermined amount of 1-methyl-2-pyrrolidone was added. The reaction was allowed to take place for about 10 minutes.

(11) In Comparative Example 9, 0.070 g of potassium-tert-butyl oxide ([8) was newly added to the polymerization system. 2.6- Add 5 g of sheet tert-p-clenol,
The solvent was removed by heating to obtain a copolymer. The basic properties of the copolymer thus obtained and the properties of the vulcanizate are shown in Table 4.

[Effects of the Invention] The random styrene-butadiene copolymer composition according to the present invention is modified with a button-like component modified with a specific amide compound and a polyfunctional coupling agent having at least three reactive sites. The copolymer composition is composed of branched components with a specific styrene chain distribution, and the styrene units in the carpenter chain have a specific styrene chain distribution. It can be used for tire applications such as tire treads, carcass, and sidewalls, as well as extruded products, automobile window frames, anti-vibration rubber, industrial supplies, etc., and has great industrial significance.

Claims (1)

[Claims] A lithium-terminated copolymer obtained by copolymerizing styrene and butadiene in a hydrocarbon solvent using an organolithium compound as a polymerization initiator, and a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ ( In the formula, R_1 represents an alkyl group, a cycloalkyl group, or an alkoxyalkyl group of C_1 to C_6, Y represents an oxygen atom or a sulfur atom, and n represents an integer of 3 to 4. −(
At least three reactions with the above lithium-terminated polymer and a linear component obtained by reacting an amide compound in which one or more hydrogen atoms of the polymethylene chain represented by CH_2)-_n are substituted with a C_1 to C_6 alkyl group. The Mooney viscosity (ML_1_+_4, 100°C) is 3.
0 to 150 styrene-butadiene copolymer, with 5 to 45% by weight of bound styrene and 1 styrene unit.
40% by weight or more of the combined styrene chains,
The long styrene chain consisting of 8 or more styrene units is not more than 5% by weight of the combined styrene, and the linear component is 2% by weight of the copolymer.
A random styrene-butadiene copolymer composition characterized in that the amount is 0 to 80% by weight, and the remaining 80 to 20% by weight is a branched component.