JPH0629339B2 - Improved rubber composition for tires - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber composition for tires having improved vulcanized physical properties and processability, and more specifically, a conjugated diene modified with a specific urea derivative compound. TECHNICAL FIELD The present invention relates to a rubber composition for a tire using a raw material rubber of a polymer rubber, a polyisoprene polymer rubber, or a butadiene polymer rubber.

[Prior Art] Conventionally, a vulcanized rubber composition containing a rubber compounding agent such as carbon black has been used for each part of a tire such as a tread, a carcass, a side wall, and a bead circumference of an automobile tire. The rubber composition used for each part of these tires is required to have different performance according to the role of each part. For example, the tread portion requires physical properties such as wear resistance, brake performance, and heat resistance, and work and processing such as roll processability, extrusion processability, adhesiveness, and adhesiveness when manufacturing tires. Since easiness is also important from an industrial viewpoint, performance in both physical properties and workability is required. In order to satisfy these requirements, the rubber raw material used in the rubber composition for each tire, carbon black, a vulcanizing agent and a vulcanization accelerator,
Other chemicals for rubber are used in various types and in various amounts according to their respective applications. Regarding the raw material rubber, natural rubber and styrene-butadiene rubber, polybutadiene rubber, butyl rubber, polychloroprene rubber, etc. are used as synthetic rubbers, but in many cases, in order to satisfy the required performance, It is used by blending two or more kinds. In particular, in recent years, automobile tires have been required to reduce rolling resistance from the viewpoint of energy saving in terms of performance, and to improve steering stability and braking performance on wet roads from the viewpoint of safety, while in terms of tire manufacturing. It has been desired to improve productivity by improving workability.

To meet these demands for improvement, for example, as a method for improving the balance between rolling resistance and wet skid resistance (braking performance on wet road surface) of a polymer for tire tread,
JP-A-54-62248 discloses a method of using a styrene-butadiene copolymer having a styrene content of 20 to 40% and a relatively large vinyl bond content and a glass transition temperature (Tg) of -50 ° C or higher. No. 57-73030 proposes a method of using a styrene-butadiene conjugated polymer having a styrene content of 3 to 30%, a vinyl bond content of a butadiene portion of 60 to 95% and branched with a specific metal compound. Has been done. However, in these cases, since the polymer has a relatively high molecular weight or a narrow molecular weight distribution, the flow characteristics of the polymer are poor,
Processability deteriorates, and to improve it, if many process oils are added or other polymers such as natural rubber are blended, the physical properties are greatly deteriorated and the target performance of these polymers is not maintained. There was a point.

Further, as a method for improving workability while improving the balance between rolling resistance performance and wet skid performance of a polymer for tire tread, for example, JP-A-58-162.
No. 605 has a wide molecular weight distribution, a method of using a branched styrene-butadiene copolymer bonded by tin, JP-A-59-45338, in combination with a coupling agent other than tin and tin. A method of using the branched styrene-butadiene copolymer thus obtained is disclosed.

[Problems to be Solved by the Invention] However, when the polymers of these techniques are used,
Although it is possible to improve the processability to some extent, when blended with other polymers, there is a problem that the characteristic physical properties are greatly reduced, and it is tried to blend with other polymers to improve various performances. In that case, it was the actual situation that the performance could not be fully exhibited.

The present invention has been made in view of the above points, and has impact resilience,
To provide a rubber composition for a tire, which is improved in various processability when manufacturing a tire while maintaining physical properties such as abrasion resistance, heat resistance, wet skid resistance, and mechanical strength. With the goal.

[Means and Actions for Solving Problems] The present invention has been made through intensive studies on a conjugated diene polymer having a functional group bonded to a polymer chain and a composition thereof, and as a result, an active polymer having a lithium terminal has been obtained. And a conjugated diene polymer obtained by the reaction of a specific urea derivative having a cyclic structure with three types of rubber-like polymers of polyisoprene rubber, styrene-butadiene rubber or polybutadiene rubber as raw rubber Compared to conventional vulcanized rubber compositions that use only raw material rubber, the rubber composition has superior impact resilience and heat resistance, and it has excellent wear resistance and wet resistance.
It was made by finding that the balance with the physical properties of skid is good and the processability of the unvulcanized compound is excellent.

That is, the present invention is a rubber composition for tires containing a raw material rubber, carbon black, an extender oil for rubber, a vulcanizing agent and other compounding chemicals for rubber, wherein the content of the raw material rubber is 30 to 90% by weight. (A) A polymer having an active lithium terminal obtained by polymerizing at least one conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound using an organic lithium compound as a polymerization initiator in a hydrocarbon solvent. And the general formula (In the formula, R ₁ and R ₂ are each independently a C _{1 to} C ₄ alkyl group or an alkoxyalkyl group, Y is an oxygen atom or a sulfur atom, and n is an integer of 2 to 4) (B) Mooney viscosity (ML _{1 + 4} , 100 ℃) of 30 to 150 (c) Glass transition temperature (Tg) of -100 to -20 ℃ [II] 5 to 65% by weight of the raw rubber is one or more selected from natural rubber or polyisoprene rubber having 90% or more of cis-1.4 bonds, and [III] 5 to 65% of the raw rubber. The weight% is one or more selected from polybutadiene rubber or a styrene-butadiene copolymer having a styrene content of 3 to 50% by weight, and the total of the raw material rubbers of [IV] [I] to [III] Is 100 parts by weight, the weight average glass transition temperature of the raw material rubbers [I] to [III] is -100 to -40 ° C, and [V] The carbon black raw rubber per 100 parts by weight of 30
〜120 parts by weight, [VI] extender oil for rubber is 5-80 per 100 parts by weight of raw rubber
The present invention relates to a rubber composition for a tire, which is contained in an amount of part by weight.

The rubber composition for a tire of the present invention has impact resilience, heat resistance,
A rubber composition for a tire, which is made of three or more rubber-like polymers as raw material rubbers, while maintaining the physical properties required for a rubber composition for a tire, such as wet skid resistance, abrasion resistance and mechanical strength. The rubber composition is suitable for each part of the tire such as the tread of the tire, the undertread, the carcass, the sidewall, and the beat part.

The present invention will be described in detail below.

The modified conjugated diene-based polymer having a specific functional group used as a part of the raw material rubber of the present invention is a conjugated diene-based polymer having an active lithium terminal at the end and a general formula (Wherein R ₁ and R ₂ are each independently a C _{1 to} C ₄ alkyl group or an alkoxyalkyl group, Y is an oxygen atom or a sulfur atom, and n is an integer of 2 to 4) It is important that the composition comprises a reaction of a urea derivative having ## STR3 ## and an effect of improving the physical properties of the composition is not seen with a composition comprising a reaction with a urea derivative having another acyclic structure. The conjugated diene-based polymer having an active lithium terminal to be reacted with such a specific urea derivative is one selected from butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, etc., using a lithium compound as a polymerization initiator, or More conjugated diene compounds,
Alternatively, it was obtained by copolymerizing a conjugated diene compound and a vinyl aromatic compound selected from styrene, α-methylstyrene, p-methyl-styrene and the like in a hydrocarbon solvent, and the polymerization reaction was substantially completed. Then, it is subjected to a reaction with the specific urea derivative.

The Mooney viscosity of the modified conjugated diene polymer (M
L _{1 + 4} , 100 ° C) is in the range of 30 to 150, and the Mooney viscosity is
If it is less than 30, the final composition, impact resilience, heat resistance and other vulcanized physical properties are inferior, and if the Mooney viscosity exceeds 1 to 50, the viscosity becomes extremely high and the dispersion of compounding agents such as carbon black It deteriorates, and the target physical properties cannot be obtained.

The glass transition temperature (Tg) of the modified conjugated diene polymer is -1.
It is in the range of 00 to -20 ° C. The glass transition temperature of the modified conjugated diene polymer is measured by DSC (Differential Thermal Scanning Meter) and can be changed depending on the type of conjugated diene compound, vinyl aromatic compound, and bonding mode of the conjugated diene compound. .

The range of the glass transition temperature is obtained rubber composition for tires, impact resilience, heat resistance, abrasion resistance strength, is a range necessary for maintaining low-temperature characteristics, any of other than the above range There is a problem with performance.

When the modified conjugated diene polymer of the present invention is a copolymer of a conjugated diene compound and a vinyl aromatic compound, the composition of the vinyl aromatic compound is within the above glass transition temperature range. As the modified conjugated diene polymer, polybutadiene, polyisoprene, butadiene-isoprene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isoprene-butadiene copolymer is preferable, and polybutadiene and styrene are particularly preferable. −
Butadiene copolymers are preferred. In this case, the vinyl bond content of the butadiene portion is preferably in the range of 10 to 85%, and the styrene content is preferably in the range of 0 to 50% by weight. The basic properties of the rubber-like polymerization vary greatly depending on the amount of vinyl bonds in the butadiene portion, the content of styrene, and the chain state of the molecules.
Various values can be set depending on the use and the type and amount of other copolymer to be blended.

Particularly in the case of a styrene-butadiene copolymer, the chain distribution of styrene (analyzed by gel permeation chromatography (GPC) of a decomposition product obtained by ozone cleavage of all double bonds of the butadiene unit) Volume 9 Issue 2055
)) Is a styrene single chain of 40% by weight or more of the styrene content and a styrene long chain of 8 or more styrene chains of 5% or less of the styrene content in order to improve impact resilience and heat resistance. Is preferred. The distribution of styrene composition in the copolymer may be uniform or non-uniform in the molecular chain.

The modified conjugated diene-based polymer of the present invention has a ratio (Mw / M) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by GPC.
The molecular weight distribution represented by n) is preferably in the range of 1.2 to 3.5 in order to have a relatively good balance between physical properties and processability.

Regarding the shape of the molecular weight distribution, it may be monomodal or may have bimodal or more bimodal GPC chromatographic peaks.

The polymer having an active lithium terminal can be obtained by the method described below.

That is, n-butyllithium, se in an inert hydrocarbon solvent such as n-hexane, cyclohexane, benzene, etc.
As a lithium-based initiator such as c-butyllithium, a conjugated diene compound is polymerized or a conjugated diene compound and a vinyl aromatic compound are copolymerized, and the microstructure of the conjugated diene portion of the obtained polymer, vinyl aromatic compound Various methods can be adopted to make the structure of the polymer such as content, chain distribution, and molecular weight distribution of the copolymer predetermined. For example, the conjugated diene moiety in the polymer is added to the polymerization system by adding a polar compound such as ethers such as diethyl ether, tetrahydrofuran, ethylene glycol diethyl ether and amines such as triethylamine and tetramethylethylenediamine. It is possible to control the microstructure and the chain distribution of the vinyl aromatic compound in the copolymer. Further, in the synthesis of the copolymer, the chain distribution can be controlled by devising the method of adding the monomer component having poor copolymerizability into the polymerization system.

The above-mentioned polymerization and copolymerization reactions are usually carried out at a reaction temperature of 0 to 150 ° C., but the conditions under which the active terminals are deactivated and the conditions under which a gel is formed by crosslinking are not preferred. The polymerization and copolymerization reactions can be carried out by any engineering method such as batch polymerization method or continuous polymerization method and a combination thereof.

The urea derivative as a modified polymer having a functional group obtained by reacting a polymer having an active lithium terminal in the present invention is a compound represented by the above general formula, and examples of these compounds include 1,3-diethyl. -2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, 1,3-dipropyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro
-2 (1H) -pyrimidinone and the like include 1,3-dimethyl
-2-Imidazolidinone is preferred.

When the urea derivative used in the present invention comes into contact with the lithium-terminated polymer, it reacts quantitatively almost instantly. Therefore, reaction with the lithium-terminated polymer is possible by adding approximately the same amount of urea derivative of active lithium.

In the present invention, it is necessary that 25% by weight or more, preferably 40% by weight or more of all polymer molecules are modified with a specific urea derivative.

In addition, the conjugated diene polymer modified with a functional group used in the present invention may partially have a branched structure. Such a branched structure is introduced for improving the low temperature flow of the polymer and improving the processability. In order to obtain a branched structure, a method of copolymerizing a small amount of a difunctional or higher functional monomer, for example, vinylbenzene, or a part of the active terminal having trifunctional or higher functional activity such as silicon tetrachloride or tin tetrachloride. A method of reacting with a halogen compound, a polyepoxy compound, polyester or the like is adopted. It is desirable that these branched structures are introduced within a range in which the characteristics of the modified conjugated diene polymer are not lost.

The modified conjugated diene-based polymer obtained in the solution by the above-mentioned production method is 2,6-di-tert-butyl after completion of a predetermined reaction.
After the addition of an antioxidant such as -p-cresol, the produced polymer is separated, and post-treatments such as washing and drying are performed to obtain the desired polymer. Also. It can also be used as a masterbatch to which a rubber extending oil such as a paraffin type, a naphthene type or an aromatic type is added.

In the rubber composition for a tire of the present invention, the modified conjugated diene polymer having the specific functional group is 30 of the raw rubber component.
~ 90% by weight, preferably 35-85% by weight is used.

When the amount used exceeds 90% by weight, there is no difference from the case of using the modified conjugated diene polymer alone. On the other hand, when the amount is less than 30% by weight, the case of using the modified conjugated diene polymer and the non-modified polymer are used. The difference from the case where it was done is practically almost nonexistent.

Next, in the rubber composition for a tire of the present invention, the rubber-like polymer which constitutes the raw material rubber together with the modified conjugated diene-based polymer of [I] is [II] natural rubber or cis-1,4
1 selected from polyisoprene rubber with a binding amount of 90% or more
One or more selected from [III] polybutadiene rubber and styrene-butadiene copolymer rubber having a styrene content of 3 to 50% by weight.

The raw rubber component of [II] is 5 to 65% by weight, preferably 10 to 60% by weight of the raw rubber, and the raw rubber component of [III] is 5 to 65% by weight, preferably 10 to 60% by weight of the raw rubber. %, And the total amount of [II] and [III] is 10 to 70% by weight of the raw rubber.

The natural rubber or the polyisoprene rubber having 90% or more of cis-1,4 bonds as the raw material rubber component of [II] is added to the rubber composition for a tire of the present invention such as heat resistance, tensile strength, and flex resistance. It is used as a component for making desirable processing characteristics such as vulcanizate properties, roll processability, extrusion processability, green strength, and tack. Particularly, of the respective uses of the rubber composition for tires, this component is necessary for tread use of large tires, sidewall use of tires in general, and carcass use.

The raw rubber component [III] is a polybutadiene rubber or a styrene-butadiene copolymer rubber having a styrene content of 3 to 50% by weight. As polybutadiene rubber, high cis polybutadiene rubber having a cis 1,4 bond content of 90% or more and low cis polybutadiene rubber using a lithium-based catalyst,
Furthermore, polybutadiene rubber having a 1,2-vinyl bond content of 30 to 85% of medium vinyl or high vinyl content is used.
Styrene-butadiene copolymer rubbers include those produced by emulsion polymerization and those having a vinyl bond content in the butadiene portion of 10-80% due to a lithium-based catalyst, and the styrene content is in the range of 3-50% by weight. , Styrene content is 50
If it exceeds 5% by weight, abrasion resistance, low temperature characteristics and heat resistance are deteriorated, which is not preferable. These polybutadiene rubbers or styrene-butadiene copolymer rubbers preferably have a Mooney viscosity (ML _{1 + 4} , 100 ° C) in the range of 30 to 150 and a glass transition temperature in the range of -110 ° C to -20 ° C.

As the above polybutadiene rubber and styrene-butadiene rubber, those having different molecular weights, molecular weight distributions, and degrees of branching are used according to the purpose of the rubber composition for a tire of the present invention.

In the rubber composition for a tire of the present invention, the raw material rubber component of [III] has improved balance in vulcanized physical properties such as tensile strength, abrasion resistance, wet skid property, and flex resistance with the raw material rubber component of [I]. In addition, it is used to control processability such as roll processability and extrusion processability, and this component is used especially in treads, sidewalls, beads, etc. for passenger car tires.

In the present invention, the total amount of the raw material rubbers [I] to [III] is 1
00 parts by weight.

In the present invention, the weight average glass transition temperature of the raw rubbers [I] to [III] is in the range of -100 to -40 ° C.

In the present invention, the weight average glass transition temperature of the raw rubber is a value represented by the following formula.

Tgm = Σwi × Tgi / ΣWi Tgm: Weight-average glass transition temperature Tgi: Glass transition of i component (measured by DSC) Wi: Weight fraction of i component Average glass transition temperature of raw rubber is rubber for tires It is appropriately selected depending on the intended use of the composition. For example, the average glass transition temperature above is -1 for rubber raw materials for treads of snow tires and studless tires where low temperature performance is important.
The range of 00 to -70 ° C is preferable, while the average glass transition temperature is -65 to -40 ° C for raw rubber of treads for high performance tires and racing tires where wet grip performance and steering stability are important. Is preferable, and in other passenger car tires and treads of large tires,
It is preferably in the range of -90 to -50 ° C. In addition, the raw material rubber of the composition of the tire portion other than the tread is also selected from the range of -100 to -40 ° C according to the application. If the average glass transition temperature of the raw material rubber exceeds -40 ° C, the low temperature characteristics deteriorate.

In the tire rubber composition of the present invention, carbon black is contained in an amount of 30 to 120 parts by weight, preferably 35 to 100 parts by weight, per 100 parts by weight of the raw material rubber. As the carbon black, it is preferable to use furnace black having a high reinforcing property, and those having a particle size of SAF, ISAF, HAF, FEF, SRF grade and the like and having various structures are used. The structure of carbon black is represented by iodine adsorption, DEP oil absorption, nitrogen specific surface area, and the like. Although the properties of the vulcanized rubber are changed by these, in the present invention, the iodine adsorption amount of 30 to 20
0 mg / g, DBP oil absorption amount 60~160cm ² / 100g, nitrogen specific surface area of 3
It is preferable to use 0 to 150 m ² / g of carbon black depending on the performance required for the rubber composition for tires. If the amount of carbon black is less than 30 parts by weight per 100 parts by weight of the raw rubber, the reinforcing effect is small and the tensile strength and the like decrease.
If it exceeds 0 parts by weight, impact resilience and heat resistance are deteriorated, which is not preferable.

The rubber composition for tires of the present invention contains the extender oil for rubber in an amount of 5 to 80 parts by weight, preferably 5 to 60 parts by weight, per 100 parts by weight of the raw rubber. As the rubber extending oil, an aromatic, naphthene or paraffin extending oil is used depending on the intended use of the rubber composition for a tire of the present invention.
For tread applications such as studless tires and snow tires that require low-temperature characteristics, and carcass applications that require heat resistance, naphthene-based and paraffin-based extenders for rubber are preferably used, and wet grip performance is required. In some applications, the aromatic oil is used in a large amount.

If the amount of the rubber extending oil is less than 5 parts by weight, the effect of improving the dispersion of carbon black by the rubber extending oil is small, while if it exceeds 80 parts by weight, the tensile strength, abrasion resistance, heat resistance, etc. are deteriorated.

The vulcanizing agent used in the composition of the present invention is mainly composed of sulfur, and peroxides and sulfur donating substances can also be used. The vulcanizing agent is used in the range of 0.05 to 5 parts by weight per 100 parts by weight of the raw rubber, and when the vulcanizing agent is sulfur, the range of 1.5 to 3.0 parts by weight is preferable per 100 parts by weight of the rubber.

Further, in the composition of the present invention, various compounding chemicals for rubber are used if necessary. Compounding agents for these rubbers include vulcanization aids such as stearic acid and zinc white, vulcanization accelerators of various systems such as sulfenamide-based, thiuram-based, guanidine-based, amine-based and phenol-based antioxidants,
There are various compounding agents such as antiozonants, processing aids, tackifiers, etc., which are appropriately used according to each application of the tire composition of the present invention.

The composition of the present invention, the above components are compounded and kneaded by an internal mixer of a known rubber kneading machine, an open roll or the like, and after being molded through a process such as extrusion, a tire such as a tread, a sidewall or a carcass. Each part is assembled and finally vulcanized at a temperature of 130 to 200 ° C for 10 to 60 minutes.

The rubber composition for a tire of the present invention has excellent impact resilience and heat resistance, and has a good balance between abrasion resistance and wet skid characteristics as compared with a composition using a conventional raw material rubber, and at the same time, Since it has good processability, it has a high degree of freedom in compounding, and in some cases, by adjusting the type and amount of carbon black and extender oil for rubber, it is possible to obtain the same impact resilience or heat resistance as conventional raw rubber compositions. Hold
It is also possible to greatly improve wear resistance and wet skid characteristics.

The rubber composition for tires of the present invention is particularly suitable for tire reds such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires, and also for sidewalls, undertreads, carcass, bead parts and the like. It can be used by taking advantage of the excellent balance between vulcanized physical properties and processability.

[Examples] Examples and comparative examples will be described below. These are illustrative of the invention and are not limiting in scope.

In the examples, the measurement of polymer structure and the physical properties of vulcanized products were performed according to the methods described below.

The Mooney viscosity is 10 using the L rotor in the usual way.
It was measured at 0 ° C. The bound styrene was calculated from the absorption based on the phenyl group at 262 nm by the ultraviolet absorption spectrum method. The microstructure of the butadiene part was calculated by the Hampton method using an infrared spectrophotometer.

For the glass transition temperature, a DSC was used, and the change in specific heat according to ASTM D3417-75 was measured, and the extrapolated temperature (Tgf) was taken as the glass transition temperature.

The tensile strength of the vulcanized product was measured according to JIS-K-6301. JIS
The impact resilience was measured at 70 ° C. according to JIS-K-6301.

For heat resistance, use a Goodrich flexometer,
Start temperature 50 ° C, load 26 lbs, displacement 5.71 mm, rotation speed
It was measured under the condition of 1800 rpm.

Abrasion resistance was measured using a pico abrasion tester. The wet skid resistance was measured by a device manufactured by the British Road Research Institute. The processability was judged by the roll operability and extrusion processability of the compound. The roll operability was evaluated by using the 6-inch roll and wrapping property and operability of the compound.

The extrusion processability was judged by the shape of the extrudate and the surface texture using a Brabender plastograph equipped with a Garvey die extruder.

The evaluation criteria for roll processability are as follows: A is one that is easy to operate with good clinging and no stickiness, A is the one that is difficult to operate due to bagging and is difficult to handle, and B is the middle, and C is the middle. In order.

As for the extrusion processability, A has good surface texture and good edge cutting, worst D has rough surface texture, uneven extrusion and poor edge shape, and the middle is B and C. .

The polymers shown in Tables 1 to 4 were used in Examples and Comparative Examples.

BR-A to BR-C and SBR-D to SBR-K shown in Table 1 are all BR (polybutadiene rubber) and SBR (styrene-butadiene rubber) modified with a specific urea compound.
BR-a to BR-c and SBR-d to SBRk shown in B are unmodified B
R and SBR are samples for comparison.

These samples were prepared by the method shown below.

Sample BR-A used cyclohexane as the solvent and had a butadiene concentration of 16% and n-butyllithium of 0.06 per 100 g of butadiene.
5 g, tetrahydrofuran 0.05 per 100 g of butadiene
Continuously feed from the bottom to the first reactor at a rate of g, keep the internal temperature of the reactor at 90 to 100 ° C, and continuously take out the polymer solution in which the polymerization reaction is completed from the top of the reactor. And fed to the second reactor. The average residence time of the reaction solution in the first reactor was 60 minutes. The temperature of the second reactor was maintained at 90 ° C., and 100 g of the polymer as 1,3-dimethyl-2-imidazolidinone corresponding to 0.95 mol per mol of the active lithium terminal was continuously added as 0.085 g as the urea compound. It was supplied and reacted to introduce a functional group. 2,6-di-tert-butyl-p as a stabilizer in the polymer solution thus obtained
-Cresol was added at a rate of 0.5 g per 100 g of polymer and the solvent was removed by heating to obtain a polymer.

Sample BR-a was obtained by the same method as in the method of obtaining sample BR-A, except that methanol was used instead of the urea compound.

Samples BR-B, SBR-E, and SBR-J were prepared by the same continuous polymerization method used to obtain sample BR-A, and reacted with urea compounds. In the adjustment of each of these samples, the amount of vinyl compound in the butadiene part was controlled by increasing or decreasing the amount of tetrahydrofuran, which is a polar compound, the Mooney viscosity was controlled by the amount of n-butyllithium, and the styrene ratio was adjusted by the supply ratio of butadiene and styrene. The content was controlled. Sample BR-B
1,3-diethyl-2-imidazolidinone was used as the urea compound.

Samples SBR-b, SBR-e and SBR-j are samples BR-B and SBR, respectively.
Corresponding to -E and SBR-J, methanol was used instead of the urea compound.

Sample BR-C was obtained by the batch polymerization method shown below, using cyclohexane as a solvent and adding 1,3-butadiene to a 15% solution of 1,3-
Tetramethylethylenediami 0.2 g per 100 g of butadiene and 0.040 g of n-butyllithium per 100 g of 1,3-butadiene were added, and the temperature inside the reactor was maintained at 30 to 35 ° C.
Let react for minutes. After completion of the polymerization reaction, 0 per 100 g of the polymer.
071 g of 1,3-dimethyl-2-imidazolidinone was added and reacted for 10 minutes. In the polymerization solution thus obtained, as a stabilizer, 2,6-di-tert-butyl-p-cresol was used as a polymer 1
0.5 g was added per 00 g, and the solvent was removed by heating.

Sample BR-c used methanol in place of the urea compound in the same manner as BR-C was obtained.

Samples SBR-D, SBR-G, SBR-H, and SBR-K are the same batch polymerization method used to obtain sample BR-C. The Mooney viscosity is adjusted by the ratio of styrene, and as a urea compound, 1,
3-Dimethyl-2-imidazolidinone was reacted to obtain a modified polymer.

Samples SBR-d, SBR-g, SBR-h, SBR-k are 1,3-dimethyl-2-
It is a polymer containing no functional group in which methanol is used instead of imidazolidinone.

Further, SBR-F was obtained by the following method.

Sample BR-C was obtained by the same batch polymerization method to obtain a styrene-butadiene copolymer having an active lithium end, and then 1/2 equivalent (1/8 mol) of tin tetrachloride to 1 mol of the active lithium end. Is added as a coupling agent to couple a part of the polymer to form a branched structure, and 1,3-dimethyl-2-imidazolidinone as a urea compound is then added to the remaining active lithium terminal at 1.0 mol ( (0.5 mol with respect to the initial active lithium end) was reacted to obtain a modified polymer.

In the polymerization solution thus obtained, as a stabilizer, 2,6-
0.5 g of di-tert-butyl-p-cresol per 100 g of polymer
And the solvent was removed by heating.

As a result of GPC analysis, the proportion branched by tin tetrachloride was 47%.

Sample SBR-f was polymerized in the same way as sample SBR-F was obtained,
After coupling with tin tetrachloride, it was obtained by reacting with methanol without using a urea compound. It is an unmodified polymer.

Further, (II) and (III) of the raw material rubber of the present invention are shown in Table 2
And the commercially available rubbery polymers shown in Table 3 were used.

Example 1 and Comparative Example 1 According to the compounding recipe shown in Table 5, the rubber composition having the blending ratio shown in Table 6 was kneaded and mixed by a pressure kneader, and roll processability and extrusion of the obtained unvulcanized product. The workability was evaluated. In addition, vulcanization was performed at 145 ° C. for an appropriate time, and the vulcanized physical properties were evaluated.

The results are shown in Table 6.

As is clear from Table 6, in the blend composition limited by the present invention, the composition using the polybutadiene modified with a functional group shows excellent processability, and has excellent vulcanization physical properties such as reaction elasticity and exothermicity. . On the other hand, a composition using unmodified polybutadiene is inferior in impact resilience and heat resistance.

Example 2 and Comparative Example 2 According to the formulation of Table 5, a rubber composition having the composition shown in Table 7 was prepared in the same manner as in Example 1, and the workability and vulcanized physical properties were evaluated. The results are shown in Table 7.

As shown in Table 7, the composition of the present invention exhibits excellent impact resilience and heat resistance as compared with the composition for comparison.

Example 3, Comparative Example 3 According to the compounding recipe shown in Table 8, the rubber composition having the composition shown in Table 9 was compounded and kneaded in the same manner as in Example 1, and the workability and the vulcanized physical properties were evaluated.

The results are shown in Table 9.

As is clear from Table 9, the composition using the styrene-butadiene rubber modified with a specific functional group of the present invention as a raw material rubber has excellent impact resilience and heat resistance, and also has good wet skid resistance and abrasion resistance. In addition, the workability of unvulcanized compound is excellent.

EFFECTS OF THE INVENTION The vulcanized rubber composition of the present invention comprises a modified conjugated diene-based polymer obtained by the reaction of a specific urea compound and a conjugated diene-based polymer having an active lithium terminal, and a polyisoprene-based polymer. A rubber composition for tires in which three kinds of raw materials, a coalesced polymer and a polybutadiene polymer, are used as a raw material rubber, and an extender oil for rubber, a reinforcing carbon black, a vulcanizing agent, and other compounding chemicals for rubber are blended, and an unvulcanized material is good. With excellent processability, excellent impact resilience and heat resistance, the balance between these and abrasion resistance and wet skid resistance is improved as compared with conventional compositions, and tire tread, undertread,
It is suitable for use in various parts of the tire such as carcass, sidewalls and beads, and can also be used for other vulcanized rubber applications by making full use of its performance, and its industrial significance is great.

Claims (1)

[Claims] 1. A rubber composition for a tire containing a raw material rubber, carbon black, an extender oil for rubber, a vulcanizing agent, and other compounding chemicals for rubber, wherein 30 to 90% by weight of the raw material rubber is [I]. (a) An active lithium-terminated polymer obtained by polymerizing at least one conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound using an organic lithium compound as a polymerization initiator in a hydrocarbon solvent. , General formula (In the formula, R ₁ and R ₂ are each independently a C _{1 to} C ₄ alkyl group or an alkoxyalkyl group, Y is an oxygen atom or a sulfur atom, and n is an integer of 2 to 4) (B) Mooney viscosity (ML _{1 + 4} , 100 ℃) of 30 to 150 (c) Glass transition temperature (Tg) of -100 to -20 ℃ [II] 5 to 65% by weight of the raw rubber is one or more selected from natural rubber or polyisoprene rubber having 90% or more of cis-1.4 bonds, and [III] 5 to 65% of the raw rubber. The weight% is one or more selected from polybutadiene rubber or a styrene-butadiene copolymer having a styrene content of 3 to 50% by weight, and the total of the raw material rubbers of [IV] [I] to [III] Is 100 parts by weight, the weight average glass transition temperature of the raw material rubbers [I] to [III] is -100 to -40 ° C, and [V] The carbon black raw rubber per 100 parts by weight of 30
〜120 parts by weight, [VI] extender oil for rubber is 5-80 per 100 parts by weight of raw rubber
A rubber composition for a tire, which comprises parts by weight.