JPH01135844A - Rubber composition for tire - Google Patents

Abstract

PURPOSE:To obtain a rubber composition having improved processability, abrasion resistance, resilience and heat build-up and suitable for tire tread, by compounding a specific raw rubber component with specific amounts of carbon black, process oil, aliphatic carboxylic acid and sulfur. CONSTITUTION:The objective rubber composition for tire can be produced by compounding (A) 100pts.wt. of a raw rubber composed of (a) 20-70pts.wt. of a polybutadiene composed of 10-70wt.% of a branched polymer bonded in branched state with a >=3-functional tin compound and 90-30wt.% of a non-branched polymer and having a trans-1,4 content of 70-90wt.%, a vinyl content of 2-10wt.% and a Mooney viscosity of 30-80, (b) 30-80pts.wt. of a natural rubber, a high-cis-1,4 polyisoprene rubber and a styrene-butadiene copolymer rubber having a glass transition temperature of <=-50 deg.C and (c) 0-30pts.wt. of a high-cis-1,4 polybutadiene and/or low-cis-1,4 polybutadiene with (B) 35-100pts.wt. of carbon black, (C) 0-50pts.wt. of a process oil, (D) 0.5-5pts.wt. of an aliphatic carboxylic acid and (E) 0.1-3pts.wt. of sulfur.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubber composition for tires that has improved processability, wear resistance, anti-1B properties, and heat generation properties.

[Conventional technology]

Conventionally, the polybutadiene used in rubber compositions for tires has a high cis content obtained using a Ziegler type catalyst.
1,4 polybutadiene and low cis-1,4 polybutadiene obtained using lithium-based catalysts have been mainly used; It was difficult to achieve both.

In addition to the polybutadiene, high trans-1,4
Polybutadiene obtained by emulsion polymerization and, more recently, polybutadiene obtained by alkaline earth metal catalysts are known as polybutadiene with a high content (Japanese Patent Application Laid-open No. 197749/1983), but these have excellent processability. However, there have been various problems such as the physical properties of the vulcanizate being unsatisfactory, and even if the processability and abrasion resistance of the vulcanizate are excellent, the repulsion properties and heat generation properties of the vulcanizate are poor.

[Problem that the invention seeks to solve]

The present invention was made against the background of the above-mentioned conventional technical problems, and has excellent workability, abrasion resistance of the obtained vulcanizate, and anti-In
It is an object of the present invention to provide a rubber composition for tires that satisfies both properties and heat generation properties.

[Means for solving problems]

That is, the present invention provides the following (A), (B) and (C)
35 to 100 parts by weight of carbon blank and 0 to 5 parts by weight of process oil to 100 parts by weight of the raw rubber component whose main component is
The present invention provides a rubber composition for a tire, characterized in that it contains 0 parts by weight, 0.5 to 5 parts by weight of an aliphatic carboxylic acid, and 0.1 to 3 parts by weight of sulfur.

(A) A polymer in which 10 to 70% by weight is bonded in a branched manner by a trifunctional or more functional tin compound (hereinafter referred to as "branched polymer") and a polymer in which 90 to 30% by weight is unbranched (hereinafter referred to as "branched polymer"). "unbranched polymer") with a trans-1,4 content of 70-90% and a vinyl content of 2-10%
20 to 70 parts by weight of polybutadiene (hereinafter referred to as "component (A)") having a Mooney viscosity (M L +-4,100°C; hereinafter referred to as "Mooney viscosity") of 30 to 80.

(B) Natural rubber, high cis-1,4 polyisoprene rubber,
and 30 to 80 parts by weight of at least one rubber selected from the group of styrene-butadiene copolymer rubbers having a glass transition temperature of 150°C or less (hereinafter referred to as "component (B)").

(C) High cis-1,4 polybutadiene and/or low cis-1,4 polybutadiene (hereinafter referred to as [(C) component]) 0 to 30 parts by weight (However, (1+ (B) + (C)
)=100 parts by weight).

First, the branched polymer in component (A) constituting the rubber composition of the present invention is polybutadiene bonded in a branched manner by a trifunctional or higher-functional tin compound, and the branched polymer in component (A) is If the ratio of coalescence is less than 10% by weight (that is, if the unbranched polymer exceeds 90% by weight), the vulcanized physical properties such as impact resilience and exothermic properties of the resulting composition will not be improved; % (i.e., when the unbranched polymer is less than 30% by weight), as described below,
When a living polymer is reacted with a tin compound, it is difficult to obtain such polybutadiene in terms of production.

Here, the proportion of the branched polymer can be determined by separation using gel permeation chromatography (CGPC) or by comparing the GPC analysis results before and after the reaction.

In addition, component (A) as a whole (i.e., branched polymer + unbranched polymer) has a trans-1°4 content of 70 to
90%, preferably 75-85%, vinyl content 2-1
0%, preferably 5-8%, and Mooney viscosity of 30-30%
80 polybutadiene.

If the trans-1,4 content of component (A) is less than 70% or the vinyl content exceeds 10%, the amount of crystals due to trans-1,4 bond chains in raw rubber will decrease, and the melting point will also decrease from -20°C. The processability is poor, and the vulcanized physical properties such as abrasion resistance and tensile strength are not improved. Furthermore, if the trans-1,4 content of component (A) exceeds 90%, the vulcanized properties such as heat generation properties and repulsion properties will be poor. Furthermore, it is difficult to obtain polybutadiene with a vinyl content of less than 2%. In particular, component (A) has a trans 1°4 content of 75
~85% and vinyl content in the range of 5 to 8%, the melting point measured by differential scanning calorimetry (DSC) of raw rubber is -20%.
Since it has stretch crystallinity at ~+40°C, it is particularly excellent in workability, and the vulcanizate has high tensile strength and does not impair its anti-fJm elasticity and heat generation properties.

Furthermore, if the Mooney viscosity of component (A) is less than 30, the resulting composition will have poor vulcanized physical properties such as abrasion resistance, anti-18 elasticity, and exothermic properties, while if it exceeds 80, processability will deteriorate.

In addition, the ratio (Mw/
Mn) is preferably 1.4 to 2.5 from the viewpoint of vulcanization physical properties such as anti-t8 characteristics and exothermic properties of the resulting rubber composition.

The ratio of component (A) in the raw material rubber of the present invention is 1
00 parts by weight, 20 to 70 parts by weight, preferably 40 to 7 parts by weight
If it is less than 20 parts by weight, it is unfavorable in terms of the vulcanized physical properties of the rubber composition, such as abrasion resistance, rebound, and exothermic properties, while if it exceeds 70 parts by weight, it is unfavorable in terms of tensile strength.

The above component (A) is obtained by polymerizing 1,3-butadiene in a hydrocarbon solvent using, for example, a barium-based catalyst as a polymerization catalyst, and adding a trifunctional or higher-functional tin compound to the resulting living polymer having an active end. Obtained by reacting.

Here, examples of the barium-based catalyst include the following catalyst systems.

(2) A catalyst comprising a barium, strontium or calcium alcoholade, an organoaluminium compound, and an organomagnesium compound described in JP-A-56-118403.

■JP-A-54-88986 or JP-A-52
A catalyst comprising barium alcoholade and organolithium described in JP-A-9090.

■Unexamined Japanese Patent Publication No. 51-115590 or Unexamined Japanese Patent Publication No. 5
A catalyst comprising a composite complex of barium, strontium or calcium and organoaluminium, and a Lewis base, a lithium alcoholade or a lithium phenolate, as described in JP 6-157409.

■Organolithium described in JP-A No. 52-98077/
Catalyst consisting of lithium alcoholade or phenolate of barium/organoaluminum/diethylene glycol monoalkyl ether or lithium salt of 2-N-dialkylaminoethanol.

■JP-A-51-23589, JP-A-56-157
411, or JP-A-56-157410, a catalyst comprising organolithium/barium alcoholade or phenolate, or salt of carboxylic acid/organoaluminum or organozinc.

■Unexamined Japanese Patent Publication No. 11296/1983 or JP-A-60-
barium alcoholade or phenolate, organolithium, organomagnesium, as described in 26406;
and a catalyst consisting of organoaluminum.

■Special Publication No. 52-48910 or JP-A-50-
A catalyst comprising barium alcoholade and organomagnesium described in JP 123628.

■Catalyst consisting of a barium compound, an organoaluminum compound, and an alkali metal salt of dialkyl ether of ethylene glycol or monoallyl ether of ethylene glycol.

■Catalysts consisting of organolithium compounds, barium alkyl phenolates, alkoxy or phenoxy silicon compounds, and alkali metal salts of ethylene glycol monoallyl ether.

[Phase] A catalyst consisting of an organolithium compound, a barium alkylphenolate, an alkoxy or phenoxyaluminum compound, and an alkali metal salt of ethylene glycol monoallyl ether.

The catalyst system used in producing the polybutadiene used in the present invention particularly preferably contains (a) an organomagnesium compound and/or an organoalkali metal compound (
(hereinafter referred to as "component (a)"), (b) organic alkaline earth metal compound (excluding organomagnesium compounds, hereinafter referred to as "component (b)"), and (C1 organic aluminum compound (hereinafter referred to as "(C) The main component is

First, (organomagnesium compounds that are one of the compounds of the al component include dicycloalkylmagnesium compounds and diallylmagnesium compounds,
Specifically, dimethylmagnesium, dipropylmagnesium, dibutylmagnesium, ethylbutylmagnesium, ethylhexylmagnesium, didecylmagnesium, dioctylmagnesium, didecylmagnesium, didodecylmagnesium, dicyclohexylmagnesium, dicyclopentylmagnesium, diphenylmagnesium, Ditolylmagnesium, ethylmagnesium bromide, ethylmagnesium chloride, allylmagnesium bromide, propylmagnesium bromide, n-
These include butylmagnesium chloride, phenylmagnesium bromide, and phenylmagnesium iodide.

Further, as the organic alkali metal compound which is the other compound of component (a), ethyllithium, propyllithium, n-butyllithium, 5ec-butyllithium, t-
Butyllithium, hexyllithium, 1,4-dilithiobutane, alkyllithium such as the reaction product of butyllithium and divinylbenzene, alkylene dilithium, phenyllithium, stilbenzenedilithium, isopropenylbenzenedilithium, sodium naphthalene, potassium naphthalene, lithium Examples include naphthalene.

These organomagnesium compounds or organic alkali metal compounds which are (al components) can be used alone or in combination.

The amount of component (a) used varies depending on the molecular weight and Mooney viscosity of the polybutadiene, but is usually 0.05 to 10 mmol, preferably 0.1 to 8 mmol, per 100 g of monomer.

In addition, the organic alkaline earth metal compounds (excluding the magnesium compound) used as component (b) are as follows:
Organometallic compounds of barium, calcium, or strontium, specifically barium jetoxide, barium jetoxide, barium diisopropoxide, barium moro-butoxide, barium di-5ec-butoxide, barium diphenoxide, barium di(1,1 -dimethylpropoxide), barium di(l,2-dimethylpropoxide), barium di(1,1-dimethylbutoxide), barium di(1,1-dimethylbentoxide)
, barium di(2-ethylhexanoxide), barium di(1-methylhebutoxide), barium diphenoxide, barium di(p-methylphenoxyto), barium di(p-butylphenoxyto), barium di(0-methylphenoxyto) , barium di(p-octyl phenoxyto), barium di(p-nonyl phenoxyto), barium di(p-dodecyl phenoxide), barium di(p-dodecyl phenoxide)
α-naphthoxide), barium di(β-naphthoxide)
, barium compounds such as barium (0-methoxyphenoxide), barium di(m-methoxyphenoxide), barium di(p-methoxyphenoxide), barium (〇-ethoxyphenoxide), barium di(4-methoxy-1-naphthoxide), etc. (However, R1-R5 are a hydrogen atom or an alkyl group or an alkoxyl group having 1 to 20 carbon atoms) is preferable in terms of performance.

Furthermore, a partial hydrolyzate in which 0.1 to 0.5 equivalents of alkoxide groups or phenoxy groups are substituted with hydroxy groups per barium atom may also be used.

Further, as the component (b), a calcium compound or a strontium compound corresponding to the barium compound can be mentioned.

The amount of component (b) used is (!!0.01 to 20 equivalents per gram atom of the metal atom of the magnesium compound or organic alkali metal compound used as the second component,
Preferably it is 0.1 to 10 equivalents.

Furthermore, the organoaluminum compound which is component (C) is
General formula AlR6R'R'' (where R''%R7 and R11 are the same or different and are selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a phenoxy group) (indicates a substituent)
It is a compound represented by trimethylaluminum, triethylaluminum, triisopropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, tricyclohexylaluminum, diisobutylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, Ethyl aluminum cybide, propyl aluminum cybide,
Examples include isobutylaluminum sibide, diethylaluminum isopropoxide, ethylaluminum diisopropoxide, aluminum isopropoxide, aluminum tri-t-butoxide, aluminum trinonyl phenoxide, diethylaluminum nonyl phenoxide, and the like.

(The amount of C1 component used is 0.02 to 2.0 equivalents per gram atom of the metal atom of the magnesium compound or organic alkali metal compound used as component (a),
Preferably it is 0.5 to 1.0 equivalent.

In addition to the above-mentioned components (a), (b), and (C), a conjugated diene may be used as a catalyst component in a proportion of 0.05 to 20 moles per mole of component (a), if necessary.

Furthermore, in addition to the above-mentioned (al, (bl, An alkali metal salt of ethanol or the like may be used in a proportion of 0.05 to 20 moles per mole of component (a).

The conjugated dienes used for catalyst preparation are isoprene, 1.3-
Butadiene, 1,3-pentadiene, etc. are used.

Although a conjugated diene or an ether compound is not essential as a catalyst component, the catalytic activity of the catalyst component is further improved by using them together.

To prepare the catalyst, for example, the (al~(C1 component) dissolved in an inert organic solvent and, if necessary, a conjugated diene or ether compound are reacted. At that time, the order of addition of each component is as follows: Any of these components may be used.It is preferable to mix, react, and age each of these components in advance in order to improve polymerization activity and shorten the polymerization initiation induction period. may be added sequentially.

Examples of polymerization solvents include inert organic solvents, such as aromatic hydrocarbon solvents such as benzene, toluene, and xylene, aliphatic hydrocarbon solvents such as n-pentane, n-hexane, n-butane, and cyclohexane, and methyl cyclohexane. Alicyclic hydrocarbon solvents such as penkune, cyclohexane, and mixtures thereof can be used.

The polymerization temperature is usually -20°C to 150°C, preferably 30 to 120°C. The polymerization reaction may be carried out batchwise or continuously.

Note that the monomer concentration in the solvent is usually 5 to 50% by weight,
Preferably it is 10 to 35% by weight.

In addition, in order to prevent deactivation of the catalyst system and polymer of the present invention in order to produce a copolymer, it is necessary to minimize the incorporation of compounds with a deactivation effect such as oxygen, water, or carbon dioxide into the polymerization system. Consideration is required.

In the present invention, 1,3-butadiene is firstly polymerized using a catalyst system in an inert organic solvent to produce polybutadiene.

The rubber composition for tires of the present invention is modified by reacting the living polymer ends of the polybutadiene obtained in this manner with a trifunctional or higher functional tin compound, and is then made from a branched polymer and an unbranched polymer. It is made by blending component (A).

This modification provides the effect of improving rebound resilience, abrasion resistance, heat generation properties, and mechanical properties.

The trifunctional or higher functional tin compound used in the present invention includes a halogen-tin bond, an aryl-tin bond, an alkoxy-tin bond, a vinyl-tin bond, or an allyl-tin bond, preferably a halogen-tin bond. A tin compound, specifically methyltrichlorotin, butyltrichlorotin, phenyltrichlorotin, tetrachlorotin, tetrabromtin, tri-11 phenyltin chloride, tetraethoxytin, diphenyltin chloride, divinyldichlorotin, tetravinyltin. , tetraallyltin, bis(methyldichlorostannyl)ethane, bis(trichlorostannyl)ethane, tetraphenyltin, tetratolyltin, bis(trichlorostannyl)ethane, etc., and these tin compounds alone However, they can also be used together.

These tin compounds contain, per gram atomic equivalent of magnesium atom or alkali metal atom in component (a),
It can be added in an amount of 0.05 to 10 equivalents, preferably 0.1 to 5 equivalents based on the halogen atom.

The reaction temperature between the polybutadiene pasting polymer and the tin compound is usually room temperature to 120°C, preferably 50°C.
~100°C, and the reaction time is usually several seconds to several hours.

After the reaction is complete, steam is blown into the polymer solution to remove the solvent, or a poor solvent such as methanol is added to solidify the polybutadiene, which is then dried on a hot roll or under reduced pressure to obtain the polybutadiene component (A). Obtainable.

Alternatively, polybutadiene can also be obtained by directly removing the solvent from the polymer solution under reduced pressure.

Next, component (B) constituting the raw material rubber of the present invention is selected from the group of natural rubber, high cis-1,4 polyisoprene rubber, and styrene-butadiene copolymer rubber having a glass transition temperature of 150°C or less. at least one type of rubber.

Among these, styrene with a glass transition temperature of 150℃ or less
Butadiene copolymer rubber usually has a bound styrene content of 35% by weight or less and a vinyl content of the polybutadiene portion of 35% by weight or less.
0% or less.

Component (B) is a rubber component necessary for maintaining breaking strength in the rubber composition of the present invention, and the proportion used thereof is 30 to 80 parts by weight, preferably 30 to 80 parts by weight per 100 parts by weight of raw rubber. is 40 to 70 parts by weight, and outside this range, the vulcanized physical properties such as abrasion resistance, repulsion properties, and heat generation properties cannot be balanced.

Furthermore, component (C) constituting the raw material rubber of the present invention is high cis-1,4 polybutadiene and/or low cis-1
, 4 polybutadiene.

Among these, high cis-1,4 polybutadiene is cis-1
,4 content is 90% or more, and low cis-1,
4 polybutadiene has a cis-1°4 content of 25-40%
, with a vinyl content of 10 to 30%.

The proportion of component (C) used is 30 parts by weight in 100 parts by weight of raw rubber.
The amount is less than 0 parts by weight, preferably 0 to 20 parts by weight, and if it exceeds 30 parts by weight, tensile strength will be poor and workability will be reduced.

A reinforcing carbon blank, process oil, aliphatic carboxylic acid, and sulfur are further blended into the rubber composition using the above components (A) to (C) as raw material rubber, and if necessary, a vulcanization accelerator. , anti-aging agents, processing aids and other rubber compounding agents.

Among these, the reinforcing carbon blacks include HAF,
Carbon black such as l5AF, SAF, etc., preferably has an iodine adsorption ff1 (IA) of 60 ttvr/g or more and a dibutyl tucrate oil absorption (DBP) of 80
ml! /100 g or more of carbon black is used. The amount of carbon blank to be used is 35 to 100 parts by weight, preferably 40 to 80 parts by weight, based on 100 parts by weight of raw rubber.If it is less than 35 parts by weight, the tensile strength and abrasion resistance of the vulcanizate are insufficient. On the other hand, if it exceeds 100 parts by weight, the anti-18 elasticity and heat generation properties will deteriorate.

Processing oils used for oil extension include, for example, paraffinic, naphthenic, and aromatic oils, but aromatic oils are preferred for applications where tensile strength and abrasion resistance are important. Naphthenic or paraffinic materials are used for applications where low-temperature properties are important, and the amount used is 0 to 50 parts by weight, preferably 10 to 40 parts by weight, and 50 parts by weight based on 100 parts by weight of raw rubber. If it exceeds this, the tensile strength and impact resilience of the vulcanized rubber will drop significantly.

Furthermore, aliphatic carboxylic acids are used as vulcanization aids and processing aids, and specifically include stearic acid, octanoic acid, lauric acid, and oleic acid. The proportion of this aliphatic carboxylic acid to be used is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the raw rubber. If it is less than 0.5 parts by weight, the dispersion of the vulcanizing agent is poor. Then,
On the other hand, if it exceeds 5 parts by weight, the vulcanization rate becomes slow.

Furthermore, sulfur is used as a vulcanizing agent, and the amount used is 0.000 parts by weight per 100 parts by weight of raw rubber. The amount is 1 to 3 parts by weight, preferably 0.5 to 2 parts by weight. If it is less than 0.1 part by weight, the tensile strength, abrasion resistance, and rebound resilience of the vulcanized rubber will decrease, while if it exceeds 3 parts by weight, it will become hard. The rubber elasticity is lost.

Furthermore, the vulcanization accelerator is not particularly limited, but preferably M (2-mercaptobenzothiazole),
DM (dibenzothiazyl disulfide), CZ (N-
Vulcanization accelerators include sulfenamide-based vulcanization accelerators such as cyclohexyl-2-benzothiazylsulfenamide), guanidine-based, and thiuram-based vulcanization accelerators, and the amount used is 0.000 parts by weight per 100 parts by weight of raw rubber. 05 to 2.5 parts by weight, preferably 0.5 to 1.8 parts by weight.

The tire rubber composition of the present invention may contain additives other than carbon blank, such as fillers such as silica, calcium carbonate, and titanium oxide, and zinc oxide, antioxidants, and antiozonants, as necessary. You can also do it.

The rubber composition for tires of the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer, and after molding, it is vulcanized and Tire Trend,
In addition to tire applications such as undertreads, carcass, sidewalls, and bead parts, it can also be used for hoses, belts, shoe soles, window frames, sealing materials, anti-vibration rubber, and other industrial products. It is suitably used as rubber for tire treads.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples; however, the present invention is not limited to the following examples as long as it does not exceed the gist thereof.

In the examples, parts and % mean parts by weight and % by weight unless otherwise specified.

In addition, various measurements in the examples were carried out by the following methods.

Mooney viscosity was measured at a temperature of 100° C. after 1 minute of preheating and 4 minutes of measurement (according to JIS K6300).

The microstructure of the polymer was determined by infrared absorption spectroscopy (Morello method).

The proportion of branched polymers can be determined by measuring the change in Mooney viscosity before and after the reaction between a living polymer immediately after polymerization using a catalyst system and a tin compound, or by performing a model reaction with a number average molecular weight of several thousand, and by CPC analysis and infrared analysis. I checked.

The physical properties of the vulcanizate were determined using raw rubber, kneaded and compounded using a 230 cc Brabender and a 6-inch roll according to the formulation shown below, and then vulcanized at 145°C for a predetermined period of time. Various measurements were performed.

Compounding prescription (part) Raw rubber
100 carbon black (SA
F) 50 stearic acid
2 Zinc white 3 Anti-aging agent (810NA) 1〃 (TP
) $2 0.8 vulcanization accelerator (MSA-G)
” 1.0 sulfur
1.5*1) N-phenyl-N'-isopropyl-p-phenylenediamine*2) N,N'-diallyl-p-phenylenediamine*3) N-oxydiethylene-2-benzothiazolesulfenamide roll processing The properties were evaluated using a 6-inch roll and observing the winding state of the rubber compound on the roll and the sheet texture, with 4 being good and 1 being poor.

For extrusion processability, the formulation was introduced into a slit die rheometer, and the extrusion amount, surface texture, and edge condition were observed, and evaluated on a four-point scale with 4 being the best and 1 being the worst.

Tensile properties (tensile strength) were measured according to JIS K6301.

Anti-tΩ elasticity is measured using a Danrosopt tripometer.
Rebound elasticity at 70°C was used.

Exothermicity (Gutudrich exothermicity) was measured using a Gutdrich flexmeter, load 48 pounds, displacement 0.225.
inch, starting temperature 50℃, rotation speed 1,800rpm
The test was conducted under the following conditions, and the temperature increase after 20 minutes is shown.

Wear resistance (Lampone wear index) is the wear amount (c
c/min) was determined and expressed as an index with the vulcanizate of Comparative Example 1 set as 100. The larger the index, the better the wear resistance.

Reference Example (Preparation of Polymer) Polymer A A dry reactor with an inner volume of 71 cm equipped with a stirrer and a jacket was purged with nitrogen, and 1.500 g of previously purified and dried cyclohexane and 500 g of 1,3-butadiene were charged. After maintaining the reactor at 70°C, 3.6 mmol of n-butyllithium and 1 mol of dinonylphenoxy barium were added.
．． A catalyst consisting of 2 mmol of triethylaluminum, 4.8 mmol of triethylaluminum, and 2.4 mmol of N-diethylaminoethoxylithium, aged at 80°C for 1 hour, was added to the reactor to initiate polymerization, and maintained at 70°C. The polymerization reaction was carried out for 2 hours, and the living polymer obtained had a concentration of 1.25
Add mmol of tetrachlorotin (SnC1a),
A branching reaction was performed.

Next, 2.5 g of 2.6-t-butyl p-cresol was added to the polymer solution, and the solvent was removed by steam stripping and dried with a roll at 110"C to obtain a polymer. Shown in Table 1.

Polymers B and C Polymers B and C were obtained by polymerizing in the same manner as Polymer A, except that the amount of catalyst was adjusted to 1.2 times and 0.8 times.

The results are shown in Table 1.

As Satooka Todan catalyst, 163 mmol of di-t-butoxybarium;
Polymerization was carried out in the same manner as Polymer A, except that 6.6 mmol of diptylmagnesium and 1.4 mmol of triethylaluminum aged at 80° C. for 15 minutes were used to obtain a polymer. The results are shown in Table 1.

Polymer E Except for changing the amount of tetrachlorotin to 0.1 mmol,
Polymer E was obtained by polymerization and reaction in the same manner as Polymer A. The results are shown in Table 1.

Polymers F and G Except for adjusting the catalyst amount to 1.5 times and 0.65 times,
Polymerization and reaction were carried out in the same manner as for polymer A, and polymers F and G were obtained.
I got it. The results are shown in Table 1.

Polymer H Butyltrichlorotin (B
Polymer H was obtained by polymerization and reaction in the same manner as for Polymer A, except that 1.25 mmol of uSnCj'l ) was used. The results are shown in Table 1.

As a biocatalyst, n-butyllithium 4.0 mmol, di-t
Polymerization was carried out in the same manner as Polymer A except that 2.0 mmol of -butoxybarium was used without aging. Results first
Shown in the table.

Polymer J Produced in the same manner as Polymer A except that 3.3 mmol of di-t-butoxybarium, 6.6 mmol of dibutylmagnesium and 1.4 mmol of triethylaluminum aged at 80°C for 15 minutes was used as a catalyst. Polymerization was performed to obtain Polymer J.

The results are shown in Table 1.

(Margin below) Table 1 Examples 1 to 9 and Comparative Examples 1 to 5 Polymers A-J obtained in Reference Examples and natural rubber (R351
), high cis-1,4 polyisoprene rubber (manufactured by Japan Synthetic Rubber, JSRrR2200), emulsion polymerization SBR (manufactured by Japan Synthetic Rubber 01, JSR3BR1500), or high cis-1,4 polybutadiene (manufactured by Japan Synthetic Rubber, J.S.
Various measurements were carried out using the vulcanized product, which was kneaded and compounded using a 1.71 Banbury and 6-inch roll according to the above-mentioned formulation using RBRol), and then vulcanized at 145 ° C. for a predetermined period of time. Ta. The results are shown in Table 2.

(The following is a blank space) [Effects of the Invention] The rubber composition for tires of the present invention has good processability of the compound, such as roll processability and extrusion processability, and
It has excellent vulcanized physical properties such as abrasion resistance, heat generation properties, anti-T8 elasticity, and tensile strength, and is particularly suitable for treads of various tires including passenger car tires and trunk bus tires.

Patent applicant: Japan Synthetic Rubber Co., Ltd. Same Brideston Co., Ltd. Agent: Patent Attorney Takashi Shirai

Claims (2)

[Claims] (1) 35 to 100 parts by weight of carbon black, 0 to 50 parts by weight of process oil, and aliphatic carboxylic acid to 100 parts by weight of the raw rubber component containing the following (A), (B), and (C) as main components. 0.5-5 parts by weight, and 0.1-5 parts by weight of sulfur.
A rubber composition for tires, characterized in that it contains 3 parts by weight. (A) A polymer with a trans-1,4 content of 70 to 70% by weight consisting of a polymer branched by a trifunctional or higher-functional tin compound and 90 to 30% by weight an unbranched polymer. 20-70 parts by weight of polybutadiene with a vinyl content of 2-10% and a Mooney viscosity (ML_1_+_4, 100°C) of 30-80. (B) Natural rubber, high cis-1,4 polyisoprene rubber,
and 30 to 80 parts by weight of at least one rubber selected from the group of styrene-butadiene copolymer rubbers having a glass transition temperature of -50°C or lower. (C) 0 to 30 parts by weight of high cis-1,4 polybutadiene and/or low cis-1,4 polybutadiene (however,
(A)+(B)+(C)=100 parts by weight). (2) The rubber composition for tires according to claim 1, wherein the polybutadiene as component (A) has a trans-1,4 content of 75 to 85% and a vinyl content of 5 to 8%.