Sumitomo Rubber Industries Limited

Ube Industries, Inc.

Nippon Paper Industries Co., Ltd.

Takahiro Mabuchi

Kazuyuki Nishioka

Toshifumi Haba

Kiyoshige Muraoka

Katsumi Terakawa

Kensuke Washizu

Kenya Watanabe

Yuko Hinohara

Mikako Yoshioka

Haruko Sawaki

Takeshi Nakayama

Takeshi Fujii

Hiroyuki Kishimoto

Kenichi Uesaka

Yuka Yokoyama

Tetsuo Mizoguchi

Tatsuhiro Tanaka

Masato Naito

Daisuke Sato

Sumiko Miyazaki

Takafumi Kawasaki

Masaki Oshimo

Koji Fujisawa

Takeshi Shoda

Kazuya Torita

Yasuchika Ito

Daiko Fujimori

Shoko Nakahata

Yuuto Kanou

Mitsuharu Ambe

Satoko Kitamura

Gen Higa

Shoko Mori

The present invention provides rubber compositions and tires which provide improved overall performance in terms of wet grip performance and dry grip performance. Included is a rubber composition having a hardness that reversibly changes with water, satisfying the relationships (1) and (2) below, and having a stress at break of 8.0 MPa or more,Hardness when dry−Hardness when water-wet≥1  (1)wherein each hardness represents the JIS-A hardness at 25° C. of the rubber composition,0.90≤Volume when water-wet/Volume when dry≤1.01  (2)wherein each volume represents the volume at 25° C. of the rubber composition.

Rubber composition and tire

The present invention provides a rubber composition for treads, containing: a rubber component including an isoprene-based rubber and polybutadiene rubber; silica; carbon black; a terpene-based resin; and a water-soluble fine particle and/or a foaming agent, the terpene-based resin having a softening point of 70-150&#xb0; C., an &#x3b1;-pinene unit content of 65-100% by mass, and a &#x3b2;-pinene unit content of 0-35% by mass, the rubber component including, based on 100% by mass thereof, 20-80% by mass of the isoprene-based rubber and 20-80% by mass of the polybutadiene rubber, with a combined amount of the isoprene-based rubber and the polybutadiene rubber of 90% by mass or more, the rubber composition containing, per 100 parts by mass of the rubber component, 20-200 parts by mass of the silica, 0.1-50 parts by mass of the carbon black, and 0.1-50 parts by mass of the terpene-based resin.

Rubber composition for tires and pneumatic tire

Provided are a rubber composition for tires that provides a balanced improvement of snow and ice performance and abrasion resistance, and a tire including the rubber composition. The rubber composition for tires contains: a rubber component including an isoprene-based rubber and BR; silica; and a terpene-based resin having a softening point of 60-150&#xb0; C., an &#x3b1;-pinene unit content of 65-100% by mass, a &#x3b2;-pinene unit content of 0-35% by mass, and a limonene unit content of 10% by mass or lower, the rubber component including, based on 100% by mass thereof, 5-80% by mass of the isoprene-based rubber and 5-80% by mass of the BR, with a combined amount of the isoprene-based rubber and the BR of 60% by mass or more, the rubber composition containing, per 100 parts by mass of the rubber component, 1-500 parts by mass of the silica and 0.1-100 parts by mass of the terpene-based resin.

A pneumatic tire having a tire component prepared by use of a rubber composition according to the present invention which comprises: a polybitadiene (i) which satisfies conditions of (A) a Mooney viscosity (ML) of 43 to 70, (B) a ratio (Tcp/ML) of 5% by mass toluene solution viscosity (Tcp) to Mooney viscosity (ML) of 0.9 to 1.7, (C) a stress relaxation time (T80), being a time until a torque is attenuated by 80% assuming that the torque at the end of MLmeasurement is 100%, of 10.0 to 40.0 seconds, (D) a molecular weight distribution (Mw/Mn) of 2.50 to 4.00, and (F) a proportion of cis-structure in microstructural analysis of not more than 98 mol %; another rubber (ii); and a rubber reinforcing material (iii), is excellent in processability and properties of tire.

Pneumatic tire

The present invention provides, inter alia, a method for producing a masterbatch in which the dispersibility of microfibrillated plant fibers is further increased to obtain excellent processability and improved rubber properties such as fuel economy, tensile strength, and elongation at break. The present invention relates to a method for producing a masterbatch, the method including step (I) of mixing a rubber latex with microfibrillated plant fibers oxidized with an N-oxyl compound to obtain a mixture, and coagulating the mixture by adjusting its pH to 2 to 6.

Method for producing master batch, master batch obtained by said production method, rubber composition for tire, and pneumatic tire

The present invention provides a rubber composition for a tire having improved workability and abrasion resistance. A rubber composition for a tire according to the present invention comprises: a polybutadiene which has: (A) a Mooney viscosity (ML) being 43 or more; (B) a ratio (Tcp/ML) of 5 wt % toluene solution viscosity (Tcp) to Mooney viscosity (ML) being 0.9 to 2.3; (C) a stress relaxation time (T80) being 10.0 to 40.0 seconds, which is a time until a torque is attenuated by 80% when the torque at the end of MLmeasurement is 100%; and (D) a molecular weight distribution (Mw/Mn) being 2.50 to 4.00; another rubber (ii); and a rubber reinforcing material (iii).

Rubber composition for tire

Provided are a rubber composition that shows a balanced improvement in fuel economy, abrasion resistance, and wet grip performance while having good processability, and a pneumatic tire including a tread formed from the rubber composition. The present invention relates to a rubber composition containing: a copolymer synthesized by copolymerization of a conjugated diene monomer and a compound represented by the formula (1) below; and carbon black and/or silica, wherein Rand Rare the same as or different from each other and each represent a hydrogen atom or a C1-C30 hydrocarbon group.

Rubber composition and pneumatic tire having tread fabricated using rubber composition

The present invention provides a pneumatic tire having high productivity and achieving a balanced improvement in fuel economy, rubber strength, abrasion resistance, wet-grip performance, and handling stability. The present invention relates to a pneumatic tire including a tread formed from a rubber composition, the rubber composition containing a rubber component in which, based on 100% by mass of the rubber component, the amount of a styrene-butadiene rubber is 15-90% by mass, the amount of a high-cis polybutadiene having a cis content of 95% by mass or more is 5-60% by mass, and the amount of a polyisoprene-based rubber is 0-70% by mass, the rubber composition containing, relative to 100 parts by mass of the rubber component, 10-150 parts by mass of a silica having a nitrogen adsorption specific surface area of 40-400 m/g, and 1-50 parts by mass of a farnesene resin obtained by polymerizing farnesene.

The present invention provides a rubber composition that can enhance the fuel economy, wet-grip performance, abrasion resistance, and kneading processability in a balanced manner, and a pneumatic tire using this rubber composition. The present invention relates to a rubber composition that contains a rubber component and silica, wherein the rubber component contains, based on 100% by mass of the rubber component, 10 to 70% by mass of a high-cis polybutadiene having a cis content of 95% by mass or more and satisfying the following requirements (A) to (C): (A) a Mooney viscosity (ML) of 40 to 49; (B) a molecular weight distribution (weight-average molecular weight (Mw)/number-average molecular weight (Mn)) of 3.0 to 3.9; and (C) an index (n-value in Expression (1) below) of velocity dependence of Mooney viscosity of 2.3 to 3.0, and 30 to 90% by mass of a conjugated diene polymer containing a constituent unit based on a conjugated diene and a constituent unit represented by formula (I) below, and an amount of the silica is 5 to 150 parts by mass per 100 parts by mass of the rubber component,log()=log()+&#xd7;log()&#x2003;&#x2003;(Expression 1)wherein RS indicates the number of revolutions per minute of a rotor, K indicates an arbitrary number, and ML indicates a Mooney viscosity, 

Rubber composition and pneumatic tire

Provided is a studless winter tire which provides good performance on ice and snow and good abrasion resistance, and suffers little change in hardness and little discoloration on the tire surface. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of a farnesene resin obtained by polymerizing farnesene. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of at least one myrcene resin selected from the group consisting of myrcene polymers with a Mw of 1,000-500,000, myrcene-butadiene copolymers with a Mw of 1,000-500,000, and myrcene-styrene copolymers with a Mw of 1,000-150,000; and a predetermined amount of a silica with an NSA of 40-400 m/g, the rubber component containing a predetermined amount of a high-cis polybutadiene with a cis content of 95% by mass or more.

Studless winter tire

Provided are a rubber composition having a good balance of improved fuel efficiency, abrasion resistance, and wet grip performance while providing good processability, and a pneumatic tire having a tread manufactured from the rubber composition. A rubber composition comprising: a copolymer synthesized by copolymerization of a conjugated diene monomer and an unsaturated acyclic monoester represented by the formula (1) below; and carbon black and/or silica, wherein Rrepresents hydrogen or a C1-C30 hydrocarbon group, and Rrepresents hydrogen or a C1-C30 hydrocarbon group.

Rubber composition and pneumatic tire having tread manufactured from said rubber composition

The present invention provides truck or bus tires having an excellent balance of fuel economy, rubber strength, and abrasion resistance together with high productivity. The present invention relates to a truck or bus tire, including a cap tread formed from a rubber composition, the rubber composition containing a rubber component including at least one selected from the group consisting of polyisoprene rubbers and polybutadiene rubber, and, per 100 parts by mass of the rubber component, 10 to 60 parts by mass of a reinforcing filler and 1 to 20 parts by mass of a farnesene resin obtained by polymerizing farnesene.

Truck or bus tires

The present invention relates to a rubber composition for a tire that includes silica and a rubber component that contains not less than 5% by mass of a conjugated diene polymer, based on 100% by mass of the rubber component, the conjugated diene polymer containing a constituent unit derived from a conjugated diene and a constituent unit represented by the following formula (I): at least one terminal of the conjugated diene polymer being modified by a compound represented by the following formula (II): 

The present invention provides a rubber composition that achieves a well-balanced improvement in fuel economy, wet-grip performance, and abrasion resistance, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition, including a rubber component and silica, wherein the rubber component contains not less than 5% by mass of a conjugated diene polymer, based on 100% by mass of the rubber component, the conjugated diene polymer containing a constituent unit derived from a conjugated diene and a constituent unit represented by the following formula (I): at least one terminal of the conjugated diene polymer being modified by a compound containing a group represented by the following formula (II): and wherein the silica is contained in an amount of 5 to 150 parts by mass per 100 parts by mass of the rubber component.

The present invention provides a rubber composition for a sidewall or base tread, which offers good flex crack growth resistance, crack initiation resistance, durability, and fuel economy despite the use of a softener derived from non-petroleum resources; and also provides a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for a sidewall or base tread, containing a rubber component including at least two kinds of diene rubbers, and a myrcene polymer, wherein the rubber component includes at least one kind of diene rubber selected from the group consisting of natural rubber, epoxidized natural rubber, and butadiene rubber, and the myrcene polymer has a weight average molecular weight of 1000 to 500000.

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Kobe, Japan

Takahiro Mabuchi