JPS6181445A - Rubber composition - Google Patents

Abstract

PURPOSE:To provide a rubber composition containing a conjugated diene polymer having tertiary amino group derived from a specific amine compound at the terminal, as an essential component, giving a vulcanized product having excellent impact resilience and tensile strength, and suitable for tire tread, etc. CONSTITUTION:100pts.wt. of a stock rubber is compounded with a conjugated diene polymer (preferably a styrene-butadiene copolymer having a vinyl content in the butadiene segment of 20-70% and styrene content of 5-40%) prepared by carrying out the solution polymerization of a conjugated diene compound (e.g. 1,3-butadiene) or said compound and an aromatic vinyl compound (e.g. styrene) in a hydrocarbon solvent in the presence of a lithium-based polymerization initiator (e.g. n-butyllithium), and then reacting with the amine compound of formula I (R and R' are H, 1-20C alkyl, etc.; n is 0-2; X is - COOR, etc.) or by carrying out the polymerization of the above monomers using the amine compound of formula II as the polymerization initiator. The amount of the conjugated diene polymer in the stock rubber is >=30wt%.

Description

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

Background of the Invention In recent years, with the demand for lower fuel consumption for self-guided vehicles, conjugated diene polymers with excellent anti-total elasticity have been required as rubber materials for tires, especially tire treads and tire undertreads. Became.

Conventionally, these conjugated diene polymers were
Conjugated diene compounds are prepared using an organolithium initiator in a hydrocarbon solvent, as described in US Pat. No. 996, U.S. Pat. or by copolymerizing a conjugated diene compound and a vinyl aromatic compound, and then reacting it with a tin halide compound or an alkenyl tin compound.

Problems to be Solved by the Invention However, since the polymer terminals are composed of carbon-tin bonds, these obtained polymers are susceptible to acidic substances such as inorganic acids, organic carboxylic acids, and Lewis acids, organic phosphorus compounds, and even organic phosphorus compounds. Due to chemical reactions with organic sulfur compounds, hydrolysis reactions under strong acids, strong alkalis, etc., the carbon-tin bond at the end of the polymer is easily broken, resulting in deterioration of physical properties, so there are restrictions on the use of additives for rubber. ing.

In order to solve the problems of the prior art, the present inventors introduced a tertiary amino group at the end of a conjugated diene polymer,
Furthermore, it was proposed to obtain a branched conjugated diene polymer with excellent processability, tensile strength, and impact resilience by combining a force/knobling agent such as a tin compound (Japanese Unexamined Patent Publication No.
No. 9-38.209), the amine compound used here is insufficient in improving the impact resilience of the vulcanizate.

The present invention focused on the physical properties and processability improvement effects unique to amino groups, and as a result of intensive studies aimed at further improving the impact resilience and tensile strength of vulcanizates, we developed a conjugated diene having a specific aromatic amino group. The present invention was achieved by discovering that a rubber composition containing a (co)polymer can further improve tensile strength and anti-fa elasticity.

A means for solving the problems, that is, the present invention, is a conjugated diene polymer having an aromatic tertiary amino group derived from an amine compound represented by the following general formula (1) and/or [II] at the terminal portion. This is a rubber composition characterized in that it contains 30% by weight or more of coalescence in 100 parts by weight of raw rubber.

(In the general formula (1) or [■], R1R' is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkenyl group, n is an integer of 0 to 2, and X is , -COORSCR"(R" is an alkyl group having 1 to 20 carbon atoms), -CN, -CHOl-COCI, COB
r, (CHz), 1lC1, (CHz), 1l
Br, (CHz)m [, m is an integer from 0 to 20. ) The conjugated diene polymer of the present invention is obtained by solution polymerizing a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon solvent using (i)'J thium-based initiator; It can be obtained by reacting an amine compound represented by the general formula (1) or by carrying out solution polymerization using an amine compound (lithium-based initiator) represented by (11) the general formula CI+).

Here, as the conjugated diene compound, 1,3-butadiene, isoprene, etc. are used, and among these, 1,3-butadiene is preferable.

Examples of the aromatic vinyl compound include styrene, vinyltoluene, p-methylstyrene, and α-methylstyrene, with styrene being preferred. The amount of such aromatic vinyl compound used is 0 to 0 based on the total amount of monomers.
40% by weight, preferably 10-35% by weight, and 40% by weight.
If it exceeds % by weight, the anti-ta elasticity and tensile strength will deteriorate, which is not preferable.

Furthermore, hydrocarbon solvents include pentane, hexane, heptane, octane, methylcyclopentane, cyclohexane, benzene, xylene, etc. Lithium-based initiators used in (i) include n-butyllithium, 5ec-butyl Lithium, alkyl lithium such as 1,4-dilithiobutane, alkyl dilithium, and 0 lithium atoms per 100 g of monomer.
．． An equivalent amount of 1 to 100 mg is used. The same applies to the case where the amine compound represented by the general formula (If) in (11) is used as a lithium-based initiator.

Examples of the amine compound represented by the general formula CI] include methyl-〇-dimethylaminobenzoate, α-dimethylaminophenylacetonitrile, p-dimethylaminoacetophenone, m-dimethylaminohenzaldehyde, etc. The amine compound is not limited to, and any amine compound that satisfies the above general formula [I] may be used.

In (1), after solution polymerization, the lithium atom at the end of the resulting conjugated diene polymer is reacted with the functional group X of the amine compound of general formula CI), and the tertiary Amino groups are bonded.

Here, the amount of the amine compound represented by the general formula (1) used is 0.1 to 3 equivalents per equivalent of the terminal lithium atom of the polymer, and the reaction temperature is 0 to 150°C. .

On the other hand, examples of the amine compound represented by the general formula (fI) include, but are not limited to, lithium benzylethylamide, lithium octylphenylamide, lithium butylphenylamide, and lithium benzylmethylamide. Any amine compound represented by the above general formula (n) may be used.

In (ii), since the amine compound represented by the general formula (I The derived tertiary amino group will be bound.

In addition, in the case of solution polymerization using the amine compound represented by the general formula [II] as a lithium-based initiator (i.e., the above (ii))
In the polymerization method shown in ), Rfi・MX' after the completion of polymerization
, , -(R is general formula CI], same as (n), n' is 1
An integer of ~3, M is tin, silicon, germanium, lead, X
′ represents a halogen atom);
Specifically, tin halide compounds such as tin tetrachloride and methyl tin trichloride, vinyl tin compounds such as tetravinyltin and butyltrivinyltin, allyltin compounds such as tetraallyltin, diethyldiallyltin, and tetra(2-octenyl)tin. compounds, tin compounds such as tetraphenyltin and tetrahensyltin, silicon tetrachloride, silicon tetrabromide,
Metal-conjugated diene bonding is achieved using coupling agents such as halogenated silicon compounds such as methyl silicon trichloride and butyl silicon trichloride, alkoxy silicon compounds such as tetraphenoxy silicon and tetraethoxy silicon, and germanium halides such as germanium tetrachloride. By forming a branched conjugated diene polymer consisting of the following, it is possible to improve the cold flow of raw rubber.

In this case, it is most preferable to use a branched conjugated diene polymer in which the branched moiety is bonded to a tin-conjugated diene bond. It can be obtained by adding 1 to 20 moles of a conjugated diene compound per 1 atomic equivalent of lithium of the amine compound (lithium-based initiator) represented by the formula, and then adding the coupling agent.

The polymerization reactions (i) and (ii) and the coupling reaction (ii) are carried out in the range of 0-120'C, and may be carried out under isothermal conditions or under elevated temperature conditions. The polymerization method may be either a batch polymerization method or a continuous polymerization method.

The microstructure of the conjugated diene part of the conjugated diene polymer is
Tetrahydrofuran, diethyl ether, dimethoxyenzene, dimethoxyethane, ethylene glycol dibutyl ether, triethylamine, pyridine, N, N, N
', N'-Tetramethylethylenediamine, dimethoxyethane and other ethers and tertiary amine compounds (1
) or (ii), the vinyl content can be freely changed within the range of 10 to 95%.

The conjugated diene polymer as described above is included in the composition of the present invention,
It is necessary to contain 30% by weight or more in 100 parts by weight of raw rubber, and if it is less than 30% by weight, it is impossible to obtain a rubber composition with high impact resilience and excellent tensile strength.

Note that the microstructure of the diene part of the conjugated diene polymer applied to the composition of the present invention is not particularly limited, but styrene-butadiene in which the vinyl content of the butadiene part is 20 to 70% and the styrene content is 5 to 40% by weight. Being a copolymer, the wet skid resistance of the resulting rubber composition,
It is preferable because the tensile strength is improved.

In addition, the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn, molecular weight distribution) determined from the gel permeation chromatogram of the conjugated diene polymer is not particularly limited, but it is considered from the balance of processability and physical properties. and 1.7-5.
It is preferably in the range of 0.

When the molecular weight distribution is within the above range, processability such as roll windability is improved, which is preferable.

Furthermore, the Mooney viscosity (M
L+ or 4.100'C) is preferably in the range of 20 to 150; if it is less than 20, the tensile properties and impact resilience will deteriorate, which is undesirable, while if it exceeds 150, it will be undesirable in terms of workability.

The rubber composition of the present invention has the conjugated diene polymer as an essential component, and contains natural rubber, high cis polyisoprene, emulsion polymerized styrene-butadiene copolymer, and no tertiary amino group at the polymer terminal. Solution-polymerized styrene-butadiene copolymer with 10-40% by weight of bound styrene and 10-80% vinyl content, low-cis polybutadiene obtained using nickel, cobalt, titanium, neodymium catalyst, ethylene-propylene-diene Blend with one or more rubbers selected from terpolymer, and add oil extenders such as aromatic process oil and naphthenic process oil, various other compounding agents, and vulcanizing agents as necessary. It can be obtained by

The rubber composition of the present invention can be used for tire applications such as tire treads, carcass and sidewalls, belts, anti-vibration rubber, window frames, hoses, industrial products and the like.

Effect: In the conjugated diene polymer used in the rubber composition of the present invention, in (i) above, the lithium atom at the end of the polymer is reacted with the functional group X in the amine compound represented by the general formula (1). In (ii), by using the amine compound represented by the general formula [■] as a lithium-based initiator, a specific tertiary amino group derived from the amine compound is added to the end of the resulting polymer. In this way, roll workability is excellent, and the tensile strength of the vulcanizate is improved.
A rubber composition with improved rebound resilience is obtained.

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples unless it goes beyond the gist of the present invention.

In addition, various measurements in the examples were based on the following.

Microstructure of butadiene moiety (vinyl content).

was determined by the infrared method (Morello method).

The styrene content was measured using a calibration curve using an infrared method based on the absorption of phenyl groups at 699 cr'.

The molecular weight distribution (Mw/Mn) is 20 manufactured by Waters.
Measured using type 0 GPC. The column is 5TYRAGEL
-106,10', 10'SlO' (4 feet x 4) was used. ? Tetrahydrofuran was used as a medium.

Mooney viscosity was measured at a temperature of 100°C, with 1 minute of preheating and 4 minutes of measurement.

Tensile strength was measured according to JIS K6301.

Wet skid resistance was measured at room temperature (25° C.) using a Stanley skid tester, and expressed as an index with Comparative Example 4 set as 100, and the larger the value, the better.

The anti↑Ω elasticity was measured at 50° C. to serve as an index of the rolling friction resistance of the tire, and a Dunlop trypsometer was used as the measuring device.

Processability was determined by the roll windability of the kneaded product on a 16-inch roll at 60°C (evaluation on a scale of 1 to 5, good) and the rollability of the kneaded product using a slit die rheometer (Japanese Patent Laid-Open No. 57-454).
It was determined from the average value of the extrusion workability (evaluation on a scale of 1 to 5, excellent), which is indicated by the sharpness of the shape and glossy corner of the compound when extruded using the method described in Japanese Patent No. 30.

Example 1-1l, Comparative Examples 1-4 After charging cyclohexane, a monomer, and tetrahydrofuran according to the recipe shown in Table 1 into a nitrogen-substituted reactor with an internal volume of 51, (i) n-butyllithium, Or (11) Lithium benzylmethylamide was added and a polymerization reaction was carried out at 30 to 90°C under heat insulation.

After the polymerization conversion rate reached 100%, in the case of (i), a certain amount of the amine compound represented by the general formula (1) was further added in an amount of 1 equivalent per 1 atomic equivalent of lithium.

Note that the polymer F was prepared in the first reactor using a reaction container with an internal volume of 101.
A solvent, a monomer, and an initiator were continuously charged so as to have the charging composition shown in the table, a polymerization reaction was carried out at a temperature of 60°C, and an amine compound was added at the outlet of the reaction vessel.

Further, the polymer was continuously charged in the same manner as the polymer F using a reactor having an internal volume of 10/cm so as to have the charging composition shown in Table 1. Note that lithium benzylmethylamide was used as the initiator.

Furthermore, polymer M is polymerized using the same recipe as polymer R.
After the polymerization was completed, methyl-O-dimethylaminobenzoate was added in the same amount as Polymer F.

Since the polymer used in this example has a large molecular weight, it is difficult to quantify the tertiary amino group (amine compound) introduced at the end of the polymer. Therefore, the amount of lithium initiator was increased using the same formulation as Polymer A, DSJ in Table 1, and the polymerization reaction was carried out in the same manner as above to obtain a (co)polymer (A) with a number average molecular weight of about i, soo. ', D', J'), and after redepositing it with methanol, the Kelpur method (Analytical Chemistry Handbook, September 20, 1980, Maruzen Publishing, No. 218)
When the nitrogen content was measured using A';1.
1%, D': 0.9%, J': 1.0%, and it was confirmed that one tertiary amino group (amine compound) was bonded to each polymer chain. Ta.

Table 2 shows the results of the microstructure (vinyl content), styrene content, molecular weight distribution, and Mooney viscosity of the butadiene moiety.

The properties of the vulcanizate were determined according to the formulation shown in Table 3.
After kneading and blending with a 0 cc brushender and a 6-inch roll, various measurements were performed using the vulcanized product, which was vulcanized at 145° C. for 30 minutes.

The results are shown in Table 4. Furthermore, SB used in Table 4
R uses SBR #1500 manufactured by Nippon Synthetic Rubber G Kiku. As is clear from Table 4, the present invention (Examples 1 to 11) is superior to Comparative Examples 1 to 4 in wet skid properties, rebound properties, workability, and tensile strength, and is excellent as a tire material. I understand that.

Table 3 Compounding recipe Polymer (rubber) 100 parts by weight HAF carbon 50 Stearic acid
2 〃Zinc white 3 〃Anti-aging agent 81ONA'' 1 〃Accelerator
CZ” 0.6〃Mth3 0.6
〃 D*4 0.4〃 *I N-phenyl-N-isopropyl-p-phenylenediamine 12 N-cyclohexyl-2-benzothiazolylsulfenamide *32-mercaptobenzothiazole *41,3-diphenylguanidine Effects of the Invention Since the rubber composition of the present invention contains as an essential component a conjugated diene polymer having a tertiary amino group derived from a specific amine compound bonded to the polymer end, the resulting vulcanization The material has high anti-jθ elasticity and high tensile strength, and is particularly useful as a tire material.

Patent applicant: Japan Synthetic Rubber Co., Ltd. Same Brideston Co., Ltd.

Claims (1)

[Claims] 1. The following general formula [I] and/or [II
] A conjugated diene polymer having an aromatic tertiary amino group derived from the amine compound represented by
A rubber composition characterized by containing 30% by weight or more in 0 parts by weight. ▲There are mathematical formulas, chemical formulas, tables, etc.▼…[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼…[II] (In the above general formula [I] or [II], R, R'
is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkenyl group, n is an integer of 0 to 2, X is -COOR, ▲ Numerical formula, chemical formula, table, etc. ▼ ( R'' is an alkyl group having 1 to 20 carbon atoms), -CN, -CHO, -COCl, -COBr, (CH_2)_mCl, (C
H_2)_mBr, (CH_2)_mI, m is 0 to 2
It is an integer of 0. 2. The rubber composition according to claim 1, wherein the conjugated diene polymer is a polymer obtained using an organolithium compound as an initiator. 3. Claim 1, wherein the conjugated diene polymer is a styrene-butadiene copolymer with a vinyl content in the butadiene portion of 20 to 70% and a styrene content of 5 to 40% by weight.
The rubber composition described in .