Sumitomo Chemical Company, Limited

Sumitomo Rubber Industries Limited

Yabuta, Takuzoh

Saito, Yuichi

Takao, Hiroyoshi

Tsuji, Mitsuji

Imai, Akio

Hiroyoshi Takao

Akio Imai

Nobuyuki Yoshida

Mitsuji Tsuji

Yuichi Saito

Masahiro Fukuyama

Kiyosi Ikeda

Keisaku Yamamoto

Hiroyuki Harada

Hideaki Yamada

Hiroshi Furukawa

Yoshio Tanimoto

Tomoaki Seki

Masaaki Hirooka

Kiyoyuki Sugimori

Junichi Koshiba

Yoshio Inoue

Kohei Nakaguchi

Hiroshi Yabuuchi

Shohachi Kawasumi

Hirotami Yamazaki

Takuzoh Yabuta

Akio Okumura

Tomoski Seki

Nabuyuki Yoshida

Herein is disclosed a vulcanizable rubber composition comprising a copolymer rubber constituted of ethylene, propylene and nonconjugated polyene, wherein ethylene/propylene molar ratio is 78/22 to 97/3 and the total content of propylene and nonconjugated polyene is 6 to 30% by mole in said copolymer rubber. By the use of the rubber composition of the present invention, a vulcanized product excellent in tensile strength, heat resistance, oil resistance, compression set resistance and flex behavior can be obtained. The vulcanized product can be used as automobile parts and other innumerable articles such as socket cover, heat resistant hose, electric wire, condenser cap, heat resistant belt, vibration-proof rubber, hoses, weather strip, seal sponge, black side wall of tire, etc.

Rubber composition

Herein is disclosed a vulcanizable rubber composition comprising a copolymer rubber constituted of ethylene, propylene and nonconjugated polyene, wherein ethylene/propylene molar ratio is 78/22 to 97/3 and the total content of propylene and nonconjugated polyene is 6 to 30% by mole in said copolymer rubber. By the use of the rubber composition of the present invention, a vulcanized product excellent in tensile strength, heat resistance, oil resistance, compression set resistance and flex behavior can be obtained. The vulcanized product can be used as automobile parts and other innumerable articles such as socket cover, heat resistant hose, electric wire, condenser cap, heat resistant belt, vibration-proof rubber, hoses weather strip, seal sponge, black side wall of tire, etc.

A modified copolymer rubber obtained by kneading at 200.degree.-280.degree. C.

Modified ethylene-.alpha.-olefin copolymer rubber and a process for

A process for preparing modified diene polymer rubbers having an increased impact resilience and a reduced hardness at low temperatures and useful as rubber materials for automobile tires and other industries which comprises producing an alkali metal-containing conjugated diene polymer, and reacting the alkali metal-containing polymer with a modifier selected from the group consisting of a nitro compound, a phosphoryl chloride compound of the formula: ##STR1## wherein R.sup.1 to R.sup.4 are independently an alkyl group, and an aminosilane compound of the formula: ##STR2## wherein R.sup.5 to R.sup.7 are independently an alkyl group or an alkoxyl group, R.sup.8 and R.sup.9 are independently an alkyl group, and n is an integer,

Process for preparing modified diene polymer rubbers

The present invention provides an ethylene-acrylic acid ester copolymer giving low deformation during vulcanization and having a high dimensional accuracy and excellent properties, as well as a process for producing said copolymer.

Ethylene-acrylic acid ester copolymer and process for producing the same

A process for preparing modified diene polymer rubbers having an increased impact resilience and a reduced hardness at low temperatures and useful as rubber materials for automobile tires and other industries which comprises producing an alkali metal-containing conjugated diene polymer, and reacting the alkali metal-containing polymer with a modifier selected from the group consisting of a nitro compound, a phosphoryl chloride compound of the formula: ##STR1## wherein R.sup.1 to R.sup.4 are independently an alkyl group, and an aminosilane compound of the formula: ##STR2## wherein R.sup.5 to R.sup.7 are independently an alkyl group or an alkoxyl group, R.sup.8 and R.sup.9 are independently an alkyl group, and n is an integer, said alkali metal-containing diene polymer being prepared by a living anionic polymerization using an alkali metal-based catalyst or by an addition reaction of a diene polymer having conjugated diene units and an alkali metal-based catalyst in a hydrocarbon solvent. The modified diene polymers can be incorporated with usual rubber additives to provide rubber compositions for various purposes, and the cured products shown an increased impact resilience and a reduced hardness at low temperatures.

Process for preparing diene polymer rubbers

In order to recover a polymer, such as styrene butadiene copolymer rubber, from a solution obtained by a solution polymerization of the corresponding comonomers, without degradation or deterioration of the polymer, the solution, ordinarily in 3 to 30% by weight concentration, is separated into the solvent and a more concentrated polymer solution of not less than 50% by weight, by heating the solution under a pressure at such a temperature (A) that the polymer does not decompose, heating a solvent, which is preferably the same as that for the solution, at a higher temperature than (A) above under a pressure, and joining the heated solution and the heated solvent in a mixer to convey to a flash evaporator.

Process for separating a polymer from a solution containing the same

A rubber composition suitable for tire treads having well-balanced excellent steering stability in cornering, wet skid characteristic, ice skid characteristic and rolling characteristic, and an excellent processability, which comprises a rubber component containing a block copolymer consisting essentially of a block A and a block B, obtained by conducting polymerization of an aromatic vinyl compound and a conjugated diene compound in a hydrocarbon solvent in the presence of an organolithium initiator and modifying with a coupling agent, and satisfying the following conditions (A) to (E); (A) the block A having a content of an aromatic vinyl compound of 5 to 29% by weight and a content of 1,2-bonds in the conjugated diene component of 25 to 55% by weight, (B) the block B having a content of an aromatic vinyl compound of 35 to 60% by weight and a content of 1,2-bonds in the conjugated diene component of 20 to 70% by weight, (C) the content of the block A in the block copolymer being from 20 to 80% by weight, (D) the average content of the aromatic vinyl compound in the block copolymer being from 20 to 40% by weight and the average content of 1,2-bonds in the conjugated diene component of the block copolymer being from 20 to 60% by weight, and (E) at least 40% by weight of the polymer chains of the block copolymer being a branched polymer formed by modification with a trifunctional or tetrafunctional coupling agent.

Rubber composition of tire tread containing block copolymer coupled with

An ethylene-.alpha.-olefin vulcanized rubber composition with excellent weather resistance and high transparency which is formed by vulcanizing with an organic peroxide an unvulcanized rubber composition comprising an ethylene-.alpha.-olefin rubber containing no metal oxide nor metal carbonate.

Ethylene-.alpha.-olefin vulcanized rubber composition

A process for preparing modified diene polymer rubbers having an increased impact resilience and a reduced hardness at low temperatures and useful as rubber materials for automobile tires and other industries which comprises producing an alkali metal-containing conjugated diene polymer, and reacting the alkali metal-containing polymer with a modifier selected from the group consisting of a nitroalkyl acrylate of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently an alkyl group and n is an integer, and a nitroamino compound of the formula: ##STR2## wherein R.sup.3 to R.sup.6 are independently an alkyl group, and m is an integer, said alkali metal-containing diene polymer being prepared by a living anionic polymerization using an alkali metal-based catalyst or by an addition reaction of a diene polymer having conjugated diene units and an alkali metal-based catalyst in a hydrocarbon solvent. The modified diene polymers can be incorporated with usual rubber additives to provide rubber compositions for various purposes, and the cured products show an increased impact resilience and a reduced hardness at low temperatures.

Modified diene polymer rubbers

A vulcanizable elastomer composition comprising an .alpha.-olefin copolymer comprising ethylene and an .alpha.-olefin(s) and an ethylene copolymer comprising ethylene and at least one member selected from the group consisting of acrylic and methacrylic esters, which has an excellent roll-processability and gives by vulcanization an elastomeric material having well-balanced properties in respect of resistance to heat and oil, low-temperature property and the like.

Elastomer composition

A rubber composition suitable for tire treads having well-balanced excellent wet skid characteristic, ice skid characteristic and rolling characteristic, and an excellent processability, which comprises a rubber component containing at least 20% by weight of a block copolymer consisting essentially of a block A and a block B, obtained by conducting polymerization of an aromatic vinyl compound and a conjugated diene compound in a hydrocarbon solvent in the presence of an organolithium initiator and modifying with a coupling agent, and satisfying the following conditions (A) to (E);

Rubber composition for tire treads containing dicarboxylic acid diester

Disclosed is a diene elastomer composition especially suitable as tread rubber of tires which has low rolling resistance and high wet grip in combination. This elastomer composition contains a rubber material comprising an elastomeric polymer component of a butadiene polymer and/or a styrene-butadiene copolymer and a rubbery component. The elastomeric polymer is produced by using an organolithium compound as a polymerization initiator, and has a long chain end concentration (LCEC) of 1.5 or less as defined by the following formula: ##EQU1## wherein .alpha.: total number of terminal groups in long chain molecules per polymer,

Diene elastomer compositions

A diene rubber composition comprising 25 to 90 parts by weight of at least one high molecular weight diene rubber (A) having an intrinsic viscosity [.eta.] of at least 2.0 and a glass transition point of not lower than -50.degree. C. and 75 to 10 parts by weight of at least one low molecular weight diene rubber (B) having an intrinsic viscosity [.eta.] of 0.01 to 2.0, said composition having an average intrinsic viscosity of at least 1.8. Since this composition has an excellent wet grip and rolling resistance property and moreover has excellent processability, it is employed as tire tread rubber.

Diene rubber composition, method of preparing the same and tire

A conjugated diene block polymer composed of blocks having a different microstructure from each other such that one block contains 20 to 60% by mole of 1,2- and/or 3,4-bonding, the other block contains 50 to 90% by mole of 1,2- and/or 3,4-bonding, the difference in the 1,2- and/or 3,4-bonding content between the both blocks is from 20 to 50% mole and the average content of 1,2- and/or 3,4-bonding in the polymer is from 50 to 85% by mole. The block polymer has a high wet skid resistance and a low dynamic heat generating property, and is very useful as a material for automobile tires.

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Chiba, Japan

Hiroyoshi Takao