The Yokohama Rubber Co., Ltd.

Kinya Kawakami

Takao Muraki

Shingo Midorikawa

Yasushi Kikuchi

Makoto Misawa

Asahiro Ahagon

Masayoshi Daio

Shigeru Shinoda

Kazuyoshi Kayama

Motoji Fujita

Atsushi Kanazawa

Eri Miura

Tetsuya Mizoguchi

A pneumatic tire in which the cap tread portion is composed of a rubber composition comprising (i) 100 parts by weight of a diene rubber having a glass transition temperature (Tg) of not more than -45.degree. C. and (ii) not more than 65 parts by weight of carbon black having a nitrogen specific surface area (N.sub.2 SA) of not less than 140 m.sup.2 /g, a DBP oil absorption of not less than 120 ml/100 g, a .DELTA.DBP of not less than 30 ml/100 g, and a half value (.DELTA.Dst) of distribution of aggregates, measured by a centrifugal precipitation method, of not more than 50 m.mu., or a pneumatic tire in which a cap tread portion is composed of a rubber composition comprising (A) 100 parts by weight of a rubber component mainly comprising natural rubber and polybutadiene rubber and having a hardness at 0.degree. C. of not more than 60 and (B) (i) carbon black having a nitrogen specific surface area (N.sub.2 SA) of not less than 120 m.sup.2 /g and a 24M4DBP of not less than 90 ml/100 g and (ii) a silica in an amount of 5 to 40 parts by weight, with the total weight of the carbon black and silica being not more than 60 parts by weight.

Pneumatic tire including cap tread portion

The cap tread portion composed of a rubber composition having a tan.delta. (0.degree. C.) of at least 0.45 and a tan.delta. (60.degree. C.) of at least 0.25 comprising (i) a p-phenylenediamine type antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline etc, and carbon black having a nitrogen specific surface area of at least 70 m.sup.2 /g and a 24M4DBP of at least 80 ml/100 g or (ii) a p-phenylenediamine based antioxidant, a 2,2,4-trimethyl-1,2-dihydroquinoline or other polymer mixture of a specific polymer content, and carbon black having a nitrogen specific surface area of at least 70 m.sup.2 /g and a 24M4DBP of at least 80 ml/100 g, blended with a rubber.

Pneumatic tire having improved abrasion resistance

Rubber compositions for use in pneumatic tire treads. Specified amounts of NR and/or IR and SBR are combined with a selected class of rubber components of the formula ##STR1## SBR contains in its molecular chains one or more atomic groups of the formula ##STR2## Rebound resilience, skid resistance and fuel saving are greatly improved.

Tread rubber compositions and method of making same

Rubber compositions are disclosed for automobile tire treads. One or more SBR rubbers of higher than -40.degree. C. in Tg are combined with carbon black of specified N.sub.2 SA, DBP, .DELTA.DBP and .DELTA.Dst qualities. The resulting composition has enhanced tan .delta. at 0.degree. C. and 60.degree. C., breaking strength, breaking energy and abrasion resistance characteristics.

Rubber compositions for tire treads of driving stability

Rubber compositions for use in tire treads are disclosed. One or more selected styrene-butadiene rubbers of specified glass transition temperatures are blended with a selected type of carbon black of specified physical characteristics. The composition is highly stable in runnability on dry, wet and snowy roads.

Rubber composition for automobile tires

Rubber compositions are disclosed for use in the tread portions of automotive tires. A selected class of starting rubbers are combined with specified amounts of a selected type of carbon black having well balanced N.sub.2 SA, 24M4DBP and .DELTA.Dst properties. The use of this carbon black is conductive to enhanced driving stability and other important physical characteristics of the tire.

Rubber compositions for tire tread

Rubber compositions particularly for use in automobile tire treads comprise a selected class of starting rubbers and specified amounts of a selected types of carbon black, this filler having specified values of IA, N.sub.2 SA/IA and .DELTA.D.sub.50 (Dst). The resulting tire excels in abrasion resistance, rebound resilience, antiskidding on wet, snowy and icy roads and fuel economy thus contributing to efficient and safe driving in all seasons.

Rubber compositions

A rubber composition for tire tread, comprising natural rubber and/or polyisoprene rubber and polybutadiene rubber, which polybutadiene rubber having a 1,2-bond unit content in the range of 40 to 90 mol % and having a specific functional group contained in the molecular chain thereof.

Rubber composition for tire treads

A rubber composition for tire treads having improved wear resistance and wet grip property without impairing rolling resistance, comprising two different specific styrene-butadiene copolymer rubbers and a specific polybutadiene rubber as the rubber ingredients in specific mixing ratios.

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Kanagawa, Japan

Kinya Kawakami