JPS6160737A - Rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition which can give a vulcanizate excellent in resiliency and tensile strength, prepared by using a conjugated diene polymer coupled with a specified tin compound as part of a rubber component. CONSTITUTION:A tin cargboxylate compound of the formula [wherein R is a (cyclo)alkyl or aryl, R' is a (cyclo)alkyl or alkenyl and x is 1-3], e.g., methyltin tristearate, is added to a reaction system in the polymerization of a conjugated diene compound (optionally, together with a vinylaromatic compound) in the presence of an organolithium compound as an initiator in a hydrocarbon solvent, and reacted to form a conjugated diene polymer rubber (of a Mooney viscosity of 20-150, a tin atom content >=100ppm, a vinylaromatic compound content <=40wt% and a glass transition temperature of -110-20 deg.C). At least 30wt.% said copolymer rubber is blended with other rubber components (e.g., natural rubber or styrene/butadiene copolymer rubber) to obtain a rubber composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rubber composition having excellent rebound resilience and tensile strength of a vulcanizate.

[Conventional technology]

With the demand for low fuel consumption for automobiles, conjugated diene-based polymers with excellent rebound resilience have been required as rubber materials for tires, especially tire tread and tire undertread rubber materials.

Conventionally, these conjugated diene polymers were disclosed in Japanese Patent Publication No. 44-499.
Publication No. 6, USP 3956232, JP-A-57-20
As described in Japanese Patent No. 5414, after polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound and a vinyl aromatic hydrocarbon compound using an organolithium initiator in a hydrocarbon solvent, a tin halide compound, It is obtained by reacting with an alkenyltin compound. However, since the obtained polymer F′i polymer terminals are composed of carbon-tin bonds, it is difficult to combine with astringent substances such as inorganic acids, organic carboxylic acids, and Lewis acids, organic phosphorus compounds, and organic sulfur compounds. The carbon-tin bond at the end of the polymer is easily cleaved by reaction, hydrolysis reaction under strong acid or strong alkali, etc.
The molecular weight changes greatly and is unstable.

When such molecular cleavage occurs, the impact resilience and tensile strength of the vulcanizate are significantly reduced. There are restrictions on the type of polymerization terminator and anti-aging agent used during the production of these polymers, the conditions during desolvation, the type of extender oil to be added, and the type of other polymers to be blended.

[Purpose of the invention]

To provide a rubber composition containing a t-conjugated diene polymer as a rubber component, in which a vulcanizate has excellent rebound resilience and tensile strength, and is subjected to a coupling reaction with a tin compound in which the molecular weight of the polymer does not change.

[Structure of the Invention] The present invention involves polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound and a vinyl aromatic compound using an organolithium compound as an initiator in a hydrocarbon solvent to form a compound of the general formula ( Here, X is an integer of 1 to 3, R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, or an aryl group, and R' is selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, or an alkenyl group. The compound obtained by reacting a tin calgexylate compound represented by the substitution fund (ML, +4.10 c) °C) is 20 ~
150, (ii) The content of tin atoms is 100 ppm or more, O
i) Vinyl aromatic compound content is 40ii, 96' or less, (ψ glass transition temperature is -1100 to -20°C
It is an object of the present invention to provide a rubber composition characterized by containing conjugated diene polymer rubber having the following characteristics in an amount of 930% or more by weight of the raw material rubber.

[Embodiments of the invention]

The conjugated diene polymer of the present invention is produced by a batch or continuous polymerization method as described below.

After polymerizing or copolymerizing a conjugated diene compound or a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent using an organolithium compound as an initiator at a temperature of 0 to 100°C, the general formula (in the formula, R, R' and (X has the above definition)
It is obtained by reacting at 100°C.

In the above polymerization or copolymerization, tetrahydrofuran, dimethΦsibenzene, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether; N, N
, N', Nl-tetramethylethylenenoamine, triethylenediamine; potassium salt of isoamyl alcohol,
Ethers, tertiary amines and potassium salts can be added, such as the potassium salt of butyl alcohol, the potassium salt of dodecylbenzenesulfonic acid.

Hydrocarbon solvents used in the polymerization of the present invention include hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, and mixtures thereof. The amount used is in the range of 1 part by weight of the monomer and 91 to 20 parts by weight.

As an organic lithium compound, n-butyllithium, 5e
c-butyllithium, tert-butyllithium, phenyllithium, 1,4-norithiobutane, etc. are used. The amount of organolithium compound is based on 100x parts of monomer,
It is used in a range of 90.02 to 0.3 parts by weight.

The polymerization reaction is carried out using a mixture of a polymerization solvent and a monomer, and if necessary, a randomizing agent or a microstructure modifier is further added. After that, an organic lithium compound is added and the reaction is carried out batchwise or continuously at a temperature of 0 to 100°C. It is held in a ceremony. The monomer can also be divided and added D″f″ during the polymerization reaction.

Suzukaru d? xylate (adding the arsenic compound@reaction between the living polymer of the produced conjugated diene polymer and the tin compound)
It is carried out in the range of 00°C.

In addition, a high molecular weight polymer with a high cis tin content can be washed out by adding and reacting a monomer with more than two functionalities such as divinylbenzene during the initial stage of polymerization and during the polymerization, and then subjecting the tin carboxylate compound to a force and f-cling reaction. Can be done @ above general formula RxSn +O-C-R') 4-x
Examples of tin carboxylate compounds represented by include methyltin trisstearate, ethyltin trisstearate, butyltin trisoctanoate, butyltin trisstearate, octyltin trisstearate, butyltin trislaurate, and dibutyltin bisoctanoate. , dibutyltin bisstearate, dibutyltin bislaurate, trimethyltin bisstearate, diethyltin bislaurate, dioctyltin bisstearate, trimethyltin bislaurate, trimethyltin stearate, tributyltin octanoate,
Tributyltin stearate, tributyltin stearate 1
",)'!J Octyltin stearate, phenyltin trisstearate, phenyltin trisoctanoate, phenyltin trislaurate, diphenyltin bisstearate, diphenyltin bisoctanoate,
Diphenyltin bislaurate, triphenyltin stearate, triphenyltin octanoate, triphenyltin laurate, cyclohexyltin trisstearate, dicyclohexyltin bisstearate, tricyclohexyltin stearate, tributyltin acetate, digtyl Tin bisacetate, butyltin trisacetate, and the like are used in a ratio of 0.2 to 3.0 equivalents of the carboxylate group of the tin carboxylate compound per 1 atomic equivalent of polymer terminal lithium of the conjugated diene polymer.

Is the conjugated diene polymer of the present invention a living polymer of conjugated diene polymer or Suzukaru? Xylate: It is obtained by reacting with an arsenic metal, and the bond between the polymer and tin is 5n-
Because it becomes a 0-C-polymer, chemical reactions and hydrolysis reactions with acidic substances, organic phosphorus compounds, and organic sulfur compounds are difficult to achieve in conventional conjugated diene-based polymers in which the bond between the polymer and tin is Sn-polymer. It is more stable than merging.
The tin carboxylated metal preferably contains at least one alkyl group and carboxylate in the molecule. The presence of an alkyl group improves the impact resilience and tensile strength of the conjugated diene polymer. On the other hand, if there is no carboxylate group, the bond between the tin compound and the polymer will not form, or the tin-carbon bond will bond the tin compound to the polymer.
Therefore, a conjugated diene polymer with excellent stability, which is the object of the present invention, cannot be obtained, and the physical properties of the rubber composition cannot be improved.

The bound tin atom content in the conjugated diene polymer is 100 p
pm or more. If it is less than 100 ppm, a vulcanizate with excellent impact resilience and tensile strength cannot be obtained. The upper limit of the tin content is not particularly limited, but is preferably 110,000 pp or less. If the tin content exceeds 1,001,000 pp, a large amount of polymerization initiator must be used (first, it is difficult to control the molecular weight within the range of ML = 20 to 150), and this is not preferred from the viewpoint of industrial production.

Mouni viscosity Fl (ML, +a,
(100°C) is 20 to 150, and if it is less than 20, workability is good, but impact resilience and tensile strength are reduced. On the other hand, if it exceeds 150, workability is poor.

The glass transition temperature (Tg) of the conjugated diene polymer is measured by a scanning calorimeter (DSC) and needs to be -20°C or lower. If Tg exceeds 120° C., the rebound resilience and tensile strength will be poor, which is not preferable. Tg is 111
It is difficult to produce a polymer at a temperature of 0° C. or lower by polymerization using an organolithium as an all-initiator.

The conjugated diene polymer of the present invention is a polymer of a conjugated diene compound or a random copolymer of a conjugated diene compound and a vinyl aromatic compound. As a conjugated tzene compound, 1,3
- One or two at selected from butadiene, isogrene, and 1,3-penmediene.

The vinyl aromatic compound is selected from 181 or 2 types from styrene, p-methylstyrene, vinyltoluene, and vinylnaphthalene. The amount used is within the range of 40x by weight in the copolymer. Specific examples include #Pi/liptatsuene, polyisoprene, poly 1,3-pentadiene, butadiene-isogrene copolymer, butadiene-1,3-pentadiene copolymer, styrene-butadiene copolymer, and styrene-isogrene co-X polymer. , p-methylstyrene-butadiene copolymer, vinyltoluene-butadiene copolymer, vinylna-7talene-butadiene copolymer, etc.
Preferred tL< is polybutadiene, styrene-butadiene copolymer.

The glass transition temperature (Tg
) is the microstructure of the conjugated diene polymer (1,2 structure or 3 structure)
, 4 structure) can be freely varied in the range from -110°C to -200°C by controlling t-control or by controlling the vinyl aromatic compound content in the copolymer.

The random copolymer of a conjugated diene compound and a vinyl aromatic compound of the present invention is a styrene-butadiene copolymer according to the oxidative decomposition method of M. Kolthoff et al. (J. Polym@r Sci, Vol. -1p4
29 (1946)), the content of the pro-cuporivinyl aromatic compound is not more than 10% by weight, preferably not more than 5% by weight of the total combined vinyl aromatic compounds. If the content of the block polyvinyl aromatic compound exceeds 10% by weight, it is not preferred because the impact resilience of the vulcanizate decreases.

The conjugated diene polymer of the present invention may be a single or natural pumice, a cis-1,4 polyisogrene emulsion-polymerized styrene-butadiene copolymer, a solution-polymerized styrene-butanoene copolymer, a high-cis
, 4 polybutadiene, low cis 1.4 polybutadiene, herogonized butyl rubber to 18! Maku is used by blending two or more types.

In the rubber composition of the present invention, it is necessary that the polymer of the present invention weighs at least 30 weight Xt, and if it is less than that, the target properties cannot be obtained and it is not preferable. can be used by extending it with highly aromatic process oil, naphthenic process oil, etc., if necessary.

The conjugated diene polymer of the present invention is vulcanized by adding ordinary compounding agents for vulcanized rubber, and is used in tires such as treads, undertreads, sidewalls, bead parts, vibration-proof rubber, hoses, belts, etc. It can be used for applications such as industrial supplies.

[Implementation row]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the scope of the present invention unless it departs from the gist of the present invention.

Implementation Pl-1 to 14. Comparison row-1 to 12: Polymers A to T were obtained using the polymerization recipe shown in Table sg1.

$2 The characteristic values are shown in the table and the ratio. Polymer A, B, S.

9. Conduct a heat aging test on TK at air F90°C. The results are shown in Table 3.

Polymer A-T, sample polymer U after heat aging test,
V, W,
Ratios listed in the table. The polymer of the present invention has superior tensile strength and rebound resilience compared to comparative lP1, and is suitable as a material for tires, tires, and other industrial products.

In addition, comparative lN-7 and 8 have physical properties equivalent to those of the composition of the present invention,
Despite K, which indicates processability, the physical properties of the polymer after the heat aging test are relatively deteriorated as shown in -9 and -10.

Remarks: *1 Is the alkyl tin cal based on 1 atomic equivalent of lithium a xylate compound or tin halide cal? Number of equivalents of xylate group or halodane *'l 5n-A
Butyltin trisstearate *3 5n-B Dibutyltin stearate book 4 5n-C)! J Butyltin stearate *5 8n-D Dimethyltin bisstearate *6 5n-E Dioctyltin bisstearate $7 5n-F Diptyltin bislaurate *8 5n-G Dibutyltin bisoctanoate *
9 5n-H dibutyltin bisacetate* 10 8
n-I Tin tetrachloride'kll 5n-J Diptyl dichlorotin Table 2 Notes: *11R method *2 1R method *3 Atomic absorption method Table 3 (Heat aging test results *1) *1 90°C in air It was carried out at

Weight part

Claims (1)

[Claims] (1) Polymerize a conjugated diene compound or copolymerize a conjugated diene compound and a vinyl aromatic compound using an organolithium compound as an initiator in a hydrocarbon solvent, and form the general formula▲Mathematical formula, chemical formula, table, etc.▼ (here where x is an integer of 1 to 3, R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, or an aryl group, and R' is a substituent selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, or an alkenyl group. (i) Mooney viscosity (ML_1_+_4, 100°C) obtained by reacting a tin carboxylate compound represented by
0 to 150, (ii) the content of tin atoms is 100 ppm or more, (iii)
) vinyl aromatic compound content is 40% by weight or less; (iv)
A rubber composition characterized by containing 30% by weight or more of a conjugated diene polymer rubber having a glass transition temperature of -110° to -20°C in a raw material rubber.