Sumitomo Rubber Industries Limited

Akira Minakoshi

Isamu Tsumori

Naohiko Kikuchi

Kiyoshige Muraoka

Hiroyuki Kishimoto

Takuya Horiguchi

Norio Taniguchi

Takuzo Iwata

Yoshikazu Tanaka

A rubber composition used for a tire, in which friction on ice is improved, which includes 0.5 to 30 parts by weight of a filler having at least two protuberances and a non-metal fiber based on 100 parts by weight of a diene rubber.

Process for preparing studless tire with tread having zinc oxide whiskers, glass fibers and porous natural glass

The present invention provides a rubber composition which can sufficiently improve performance on ice and snow and wet gripping properties, and a pneumatic tire using the same. The rubber composition comprises, based on 100 parts by weight of diene rubber (A), 2 to 20 parts by weight of short fiber (B) having an average fiber diameter of 10 to 100 &#x3bc;m and average fiber length of 0.01 to 4 mm, 1 to 10 parts by weight of particles (C) having a Moh's hardness of at least 5 and average particle size of at most 500 &#x3bc;m, and 1 to 15 parts by weight of starch/plasticizer composite material (D), and the pneumatic tire has a tread made of the rubber composition.

Rubber composition and pneumatic tire using the same

The present invention provides a studless tire excellent in performance on ice and snow in which digging friction is improved without losing adhesion friction. The studless tire has a tread comprising specific short fiber or plate-like material dispersed in diene rubber so as to be oriented in the tread thickness direction, wherein when measured at 25&#xb0; C. the tread has a complex elastic modulus E1 in the tread thickness direction, and the sheet has a complex elastic modulus E&#x3b1; in the extrusion direction and a complex elastic modulus E&#x3b2; in a 90&#xb0; direction from the extrusion direction, when the rubber composition is made into 2 mm sheets with a roller and these moduli fulfill the following equation,60&#x2266;(1&#x2212;&#x3b2;)/()&#xd7;100&#x2266;100and the tread has a specific tread rubber hardness. The tire is obtained using a tread prepared by extruding a rubber composition containing diene rubber and specific short fiber or plate-type material in a tube shape, thereby orienting the short fiber in the circumferential direction of the tube shaped rubber, then cutting the obtained rubber sheet parallel to the extrusion direction, rotating each piece 90&#xb0; and laminating.

Process for preparing rubber sheet and tread and studless tire using same

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Kobe, Japan

Akira Minakoshi