The Yokohama Rubber Co., Ltd.

Zeon Corporation

Takashi Shirokawa

Makoto Ashiura

Yoshihiro Kameda

Ayumi Naka

Masaki Satou

Keisuke Maejima

Masao Nakamura

Koichi Endo

Yasushi Kikuchi

Naoya Amino

Misao Hiza

Hideyuki Oishi

Takeshi Hotaka

Makio Mori

Jun Shimada

Hajime Fujii

Tetsuo Ochiai

A rubber composition comprises a diene rubber including not less than 30% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 1 to 25 parts by weight of a tackifying resin, and from 25 to 80 parts by weight of a filler comprising not less than 50% by weight of silica. The modified conjugated diene polymer rubber has a terminal modified group comprising a functional group that interacts with silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, weight-average molecular weight is from 600,000 to 1,000,000, and glass transition temperature is from &#x2212;22 to &#x2212;32&#xb0; C. A glass transition temperature of the tackifying resin is from 50 to 110&#xb0; C. higher than the glass transition temperature of the modified conjugated diene polymer rubber.

Rubber composition for use in tire treads

A rubber composition for use in tire treads comprises a diene rubber including not less than 40% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 66 to 110 parts by weight of a filler. The filler comprises not less than 50% by weight of silica. The modified conjugated diene polymer rubber is obtained by copolymerizing a conjugated diene monomer unit and an aromatic vinyl monomer unit in a hydrocarbon solvent using an organic active metal compound as an initiator. A resulting active conjugated diene polymer chain thereof has a terminal modified group, obtained by reacting at least one type of compound having a functional group that is reactable with the active terminal of the polymer chain. Moreover, the terminal modified group has a functional group that interacts with the silica.

A rubber composition comprises a diene rubber including not less than 25% by weight of a modified conjugated diene polymer rubber and, per 100 parts by weight of the diene rubber, from 25 to 65 parts by weight of a filler, the filler comprising not less than 50% by weight of silica. The silica has a DBP absorption number of 190 to 250 ml/100 g, an NSA of 194 to 225 m/g, and a CTAB of 185 to 215 m/g. A ratio of the NSA to the CTAB is from 0.9 to 1.4. The modified conjugated diene polymer rubber has a terminal modified group including a functional group that interacts with the silica. In the modified conjugated diene polymer rubber, aromatic vinyl unit content is from 38% to 48% by weight, vinyl unit content is from 20% to 35%, and weight-average molecular weight is from 600,000 to 1,000,000.

Rubber composition for tire tread

A rubber composition containing (i) a conjugated diene-based rubber gel having a toluene swelling index of 16 to 70, (ii) a diene-based rubber such as natural rubber, polyisoprene rubber, aromatic vinyl-conjugated diene copolymer rubber and/or polybutadiene rubber, and (iii) an optional carbon black and/or silica and (a) a pneumatic tire using this composition as a high hardness reinforcing layer extending from a bead along a tire sidewalls, in which the fluidity and dimensional stability at the time of extrusion are improved, while maintaining a sufficient hardness of a high hardness reinforced rubber, (b) a pneumatic tire using this composition as two ends of a tire tread extrudate, maintaining a flex fatigue of the two ends of the tread, in which the extrudability and extrusion dimensional stability are improved and (c) a pneumatic tire using the composition as a 1.5 mm to 6 mm thick undertread, in which a high elasticity and relatively thick gauge undertread, and excellent processability and steering stability are provided.

Rubber composition and pneumatic tire using the same

A rubber composition comprising 100 parts by weight of a diene rubber and 0.5 to 20 parts by weight of a foaming agent-containing resin containing 5 to 65% by weight of a chemical foaming agent, wherein the resin is mainly a polyolefin resin which is not co-crosslinkable with the diene rubber and wherein the rubber composition is structured having microcapsule-shaped bubbles coated with a resin layer after vulcanization of the rubber.

Rubber composition for tire and process of production thereof

This invention relates to a rubber composition for seismic isolation laminate which exhibits excellent damping capacity as well as sufficient hardening properties. Such rubber composition for a seismic isolation laminate comprises at least a diene rubber; and 40 to 160 parts by weight of carbon black having a CTAB specific surface area of 120 to 370 (m,/g) and a CTAB specific surface area (m,/g)/iodine adsorption (mg/g) of up to 1.0 per 100 parts by weight of the diene rubber.

Rubber composition for seismic isolation laminates

A rubber composition for a tire tread comprising (i) 100 parts by weight of a diene based rubber containing at least one styrene-butadiene copolymer rubber having a glass transition temperature of -60.degree. C. to -20.degree. C. and (ii) 20 to 75 parts by weight of carbon black having CTAB of 85 to 110 m.sup.2 /g, C-DBP of more than 105 ml/100 g, N.sub.2 SA/IA of more than 1.10, Tint of more than 105, .DELTA.Dst of 60 to 80 nm, and CTAB of less than 230-5.8 (dn) wherein dn is the average particle size (nm), measured by an electron microscope.

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Hiratsuka, Japan

Takashi Shirokawa