Zeon Corporation

Other

Tokuyama Corporation

Takeshi Karato

Masao Nakamura

Takahiko Fukahori

Tetsuji Kawazura

Yasushi Kikuchi

Masayuki Kawazoe

Toru Nakamura

Takeshi Sugimura

Osamu Yatabe

Tatsuo Sasajima

Yoshihiro Chino

Koichi Endo

Masaaki Komatsu

Kiyonori Umetsu

Kazutaka Watanabe

Shinji Tokunaga

Kouji Shouya

Manabu Tomisawa

Masaaki Komatu

Kazuhiro Takase

Tsunetoshi Sugimura

Kazutake Watanabe

Kazuya c/o Zeon Corporation Ito

For a tire excellent in strength, low-heat buildup property, wet grip property, and driveability, and a rubber composition and a conjugated diene rubber for the tire, a conjugated diene rubber of the present invention includes 5 wt % or more of a structure that 3 or more conjugated diene polymer chains are bound via a denaturing agent, obtained by reaction of each chain and the agent, each chain being that at least one of terminals is an isoprene block having 70 wt % or more of an isoprene monomer unit, and the other is an active terminal, the agent having, per molecule, at least one of an epoxy group(s) and a hydrocarbyloxysilyl group(s), and being that a total number of the epoxy group(s) and hydrocarbyloxy groups in the hydrocarbyloxysilyl group(s) per molecule is 3 or more.

Conjugated diene rubber, rubber composition, crosslinked rubber, tire, and process for production of conjugated diene rubber

A conjugated diene rubber of the present invention is prepared from conjugated diene polymer chains, wherein the conjugated diene polymer chains each has an active end at one end and an isoprene block at least at the other end, the isoprene block contains 70 wt % or more isoprene monomer units, and the active ends of at least part of the conjugated diene polymer chains are modified with a compound having a &#x3e;C&#x2550;O group as a functional group. This provides (i) a tire that has an excellent strength, excellent low-heat buildup property, and excellent wet grip property and (ii) a rubber composition and a conjugated diene rubber that are suitably used to produce the tire.

Conjugated diene rubber, rubber composition, cross-linked rubber, and tire

A conjugated diene rubber composition comprising (A) 5-95 wt. % of a conjugated diene rubber having a structure such that at least three conjugated diene polymer chains are bonded together through a specific polyorganosiloxane having groups containing alkylene glycol repeating units and (B) 95-5 wt. % of a conjugated diene rubber having reacted with a compound having in the molecule a functional group selected from &#x3e;C&#x2550;O, &#x3e;C&#x2550;S, amino, imino, epoxy, pyridyl, alkoxyl and halogeno. This rubber composition gives, when silica is incorporated therein, a vulcanizable rubber composition having good processability and giving a rubber vulcanizate exhibiting sufficiently reduced heat build up, and having good wet-grip property and good abrasion resistance.

Conjugated diene rubber compostion, process for producing the same and rubber vulcanizate

Disclosed are silica-filled rubber granules comprised of a cocoagulation product of rubber and silica, which are extremely less powdery and excellent in handling and kneading, as well as an industrially advantageous process for producing same. The silica-filled rubber granules of the present invention are dried granules of a cocoagulation product of rubber and silica particles, which are characterized in that an average particle diameter (D50) in terms of the sieve analysis is 300&#x2dc;3000 &#x3bc;m and the weight ratio of the granules within the range of D50&#xb1;(D50&#xd7;0.5) is at least 50% by weight. The silica-filled rubber granules are produced by supplying a cake of a cocoagulation product of silica and rubber having a water content of 40&#x2dc;80% by weight to a drier provided with an indirect-heating type container having stirring wing blades, and then drying the cake while stirring it with the stirring wing blade.

Silica-loaded granular rubber and process for producing the same

The present invention is to provide a diene rubber composition and a cross-linked diene rubber thereof excellent in tensile strength, wear resistance and processability, keeping compatibility of both good fuel efficiency and high gripping property, and a production method thereof. What is characterized in the composition is that the composition is comprised of 100 parts by weight of a diene rubber having a molecular weight distribution expressed in terms of the ratio of the weight-average molecular weight to the number-average molecular weight of 1.1 to 30, 20 to 200 parts by weight of silica and a cationic polymer, and that a toluene-insoluble rubber content per gram of the silica within the range from 0.2 to 1 g, and diene cross-linked rubber thereof. What is characterized in the production method is that the method comprises steps of allowing rubber latex stabilized by an anionic emulsifying agent to react with an aqueous suspension of silica containing a cationic polymer and effecting co-coagulation of rubber in the rubber latex with the silica in the aqueous suspension within a specific pH range.

Diene rubber composition and process for producing the same

A conjugated diene rubber obtained by a process wherein active conjugated diene polymer chains each having an active metal at a polymer chain terminal, which have been obtained by polymerizing a conjugated diene monomer alone, or a conjugated diene monomer and an aromatic vinyl monomer with the aid of an organic active metal in an inert solvent, are allowed to react with a specific polyorganosiloxane capable of reacting with the active metal bonded to the polymer chain terminal. The conjugated diene rubber contains at least 5% by weight of a structure comprising at least three conjugated diene polymer chains bonded through a polyorganosiloxane. The conjugated diene rubber gives, when silica is incorporated therein, a rubber composition having good processability and giving a crosslinked rubber having reduced heat build-up, good wet grip performance and good abrasion resistance.

Conjugated diene rubber, process for producing the same, and rubber composition

An oil-extended rubber comprising a conjugated diene rubber having a specific amount of isoprene units, and an extender oil incorporated therein, characterized in that the rubber is obtained by polymerizing a monomer mixture comprising 1,3-butadiene and an aromatic vinyl monomer with the aid of an organic active metal as an initiator in a hydrocarbon medium; subsequently adding isoprene to continue polymerization, then; reacting the resulting polymer having an activated terminal with a coupling agent. A rubber composition comprising the oil-extended rubber is suitable for tread of tire having a low fuel consumption.

Oil extended rubber and rubber composition

A diene rubber (A) having a weight average molecular weight (Mw) of 100,000 to 3,000,000, an Mw/number average molecular weight (Mn) ratio of 1.30 to 2.50, and an Mw/peak top molecular weight (Mp) ratio 0.70 to 1.30. A rubber composition comprising the diene rubber (A) and a diene rubber (B) having an Mw of 2,000 to 90,0000 and/or an oil extender for rubber has good processability and can give a rubber vulcanizate having high tensile strength and good abrasion resistance. The diene rubber (A) is produced by conducting a living polymerization of diene monomer in a hydrocarbon solvent; adding a polymerization stopper to a polymerization mixture at a conversion of 5 to 98% to deactivate 10 to 90% by mole of active terminals present as of the initiation of polymerization; and finally adding a polymerization stopper to completely terminate the polymerization reaction.

Diene rubber, process for production thereof, rubber compositions, process for producing the same, and crosslinked rubbers

An oil-extended rubber comprising 100 weight parts of a rubber ingredient comprising a conjugated diene rubber wherein the ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is in the range of 1.2 to 2.2, and the conjugated diene monomer units have a vinyl bond unit content of at least 20%, and 5-100 weight parts of a process oil having a total acid value of not larger than 1.0 mgKOH/g, a pour point of not higher than 50&deg; C. and an aromatic carbon content of at least 20%. A rubber composition comprising 100 weight parts of the above-mentioned rubber ingredients, 5-100 weight parts of the process oil and 10-200 weight parts of a reinforcing agent. This rubber composition gives a crosslinked article having high tensile strength, high abrasion resistance and reduced heat build-up, and is useful, for example, as an automobile tire material.

Oil-extended rubber, process for producing the same, rubber composition, and crosslinked object

A tapered aromatic vinyl-conjugated diene copolymer rubber having a ratio W /W in the range of 0.65-0.9 or 1.1-1.3 wherein Mp is molecular weight of a copolymer molecule corresponding to the peak of a molecular weight distribution curve obtained by gel permeation chromatography, W is a weight fraction of aromatic vinyl monomer units in the copolymer molecule having a molecular weight Mp, and W is a weight fraction of aromatic vinyl monomer units in a copolymer molecule having a molecular weight of Mp&times;0.6. A coupled tapered rubber comprised of a plurality of tapered copolymer molecules which are bound together at molecule terminal. A rubber composition comprising this tapered rubber or coupled tapered rubber and natural rubber or a synthetic rubber. This rubber composition exhibits reduced heat build-up, and high wet skid resistance, tensile strength and abrasion resistance.

Tapered aromatic-vinyl/conjugated-diene copolymer rubber, process for producing the same and rubber composition

A block copolymer (1) containing a polymer block A of a conjugated diene and a random copolymer block B of a conjugated diene and aromatic vinyl compound, (2) having a weight ratio (A:B) of the polymer block A and the copolymer block B of 5:95 to 95:5, (3) having a bound aromatic vinyl compound content in the copolymer block B of 1 to 50% by weight, (4) having a weight average molecular weight (Mw) of 100,000 to 5,000,000, and (5) having at least two transition points measured by differential scanning calorimetry in the range of &minus;150&deg; C. to &plus;150&deg; C., a method of production of the same, and a rubber composition and pneumatic tire containing the same.

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Tokyo, Japan

Takeshi Karato