Bridgestone Corporation

Kazuya Hatakeyama

Yasushi Hirata

Daisuke Nohara

Masahiro Hojo

Kazuaki Someno

Franco Cataldo

Ichiro Nakajima

A family of tire sizes are classified into plural groups every tact time and only sizes belonging to the same group are selected from the family of tire sizes and allocated in a plurality of vulcanization stations vulcanizing tires, whereby tires of plural sizes can be vulcanized at a mixed state for a given tact time without requiring middle stock for green tires.

Vulcanized tire size allocating method, tire manufacturing method, and vulcanizing process setting method

A rubber composition for use in a tread of a pneumatic tire comprises particular amounts of particular nitrogen-containing compound and particular proton acid or derivative thereof based on 100 parts by weight of rubber ingredient, and develops an excellent gripping performance.

Rubber compositions for tire tread developing excellent gripping performance

A silica-blended rubber composition comprising 100 parts by weight of sulfur-vulcanizable rubber blended with 10 to 100 parts by weight of silica, 3 to 20% by weight of a silane coupling agent based on the silica and 1 to 20% by weight of sodium borate based on the silica. An alkoxy group-containing silane coupling agent is preferred as the silane coupling agent, and sodium tetraborate is preferred as the sodium borate.

Silica-blended rubber composition and production process for the same

Rubber composition improved in charging property and pneumatic tire

Rubber composition

A low heat generation type rubber composition is disclosed, which comprises at least one rubber selected from the group consisting essentially of natural rubber and a synthetic diene rubber, a reinforcing filler, and a thiadiazole compound expressed by the following general formula: ##STR1## in which R.sub.1 and R.sub.2, which may be the same as or differ from each other, denote a mercapto group, an amino group and a trifluoromethyl group. The reinforcing filler and the thiadiazole compound are contained in amounts of 20 to 150 parts by weight and 0.1 to 10 parts by weight, respectively.

Low heat generation rubber compositions containing thiadiazole compound

A rubber composition containing a specifically limited imidazole compound or imidazoline compound, or benzimidazole or its specifically limited derivative has a large tan .delta. at high temperature range, and a tire having a tread using such rubber composition is prevented from being lowered in the value of tan .delta. due to the temperature rising during the running and has an improved grip performance during the high speed running. The use of Bronsted acid in combination with the imidazole, imidazoline or benzimidazole can obviate the drawback of poor scorch resistance of a rubber composition containing the imidazole, imidazoline or benzimidazole alone, and the resulting rubber composition has a very large tan .delta. at high temperature range, and a tire having a tread using the rubber composition has a remarkably improved grip performance during the high speed running.

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Kodaira, Japan

Kazuya Hatakeyama