Sumitomo Rubber Industries Limited

Ritsuo Nakayasu

Shinichi Miyazaki

Kazuo Hochi

Takao Wada

Yoichi Mizuno

Masato Kawase

A rubber composition for tire and a pneumatic tire in which the rubber composition is used improve steering performance on snowy and icy roads as well as traction performance in the forward and backward directions while reducing the recycling and manufacturing cost. The rubber composition for tire contains from 0.5 to 12 parts by weight of paper relative to 100 parts by weight of a rubber component, and preferably further contains from 5 to 100 parts by weight of silica and from 2 to 15 parts by weight of short fiber relative to 100 parts by weight of the rubber component. The paper is newspaper waste. From 10 to 100 parts by weight of carbon black may further be contained relative to 100 parts by weight of the rubber component.

Rubber composition for tire and pneumatic tire

A pneumatic radial tire containing a non-metallic cord breaker belt disposed radially outside a carcass, and a jointless band belt disposed radially outside the breaker belt, said band belt being made of at least one hybrid cord wound spirally and continuously in the circumferential direction of the tire at an angle of 0 to 3 degrees with respect to the tire equator. The hybrid cord includes a low elastic modulus thread and a high elastic modulus thread which are finally-twisted together, said low modulus thread having at least one low modulus fiber, first-twisted and having an elastic modulus of not more than 2000 kgf/sq.mm and said high modulus thread having at least one high modulus fiber first-twisted and having an elastic modulus of not less than 3000 kgf/sq.mm. In the band belt ply, the count (E) of the hybrid cord per 5 cm width, the stress (F1) in kgf of the hybrid cord at 2% elongation, and the stress (F2) in kgf of the hybrid cord at 6% elongation satisfies the following relationships: FI.times.E&lt;60; and F2.times.E&gt;150.

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Kobe, Japan

Ritsuo Nakayasu