The Yokohama Rubber Co., Ltd.

Kazuhiro Yamada

Toshio Kobayashi

Makoto Misawa

Asahiro Ahagon

Yasuhiro Ishikawa

Yuichi Sugiyama

Masashi Kida

Shigeru Shinoda

Yoshio Tajima

Jun Shimada

Tsuneo Koyama

Teruhide Furuhama

Masaaki Obara

Hiroshi Kakiuchi

Seiichi Doi

Rubber compositions of a selected base rubber and a specified paraffin was containing 50% or more of a normal paraffin and having a carbon area ratio of less than 4.0 as determined by gas chromatography within a carbon number range of from 23 to 42. The ratio is derived by counting a first paraffin content which is defined by the paraffin of maximum content in the wax and a second paraffin content which is defined by the paraffin of minimum content in the wax and thereafter dividing the first paraffin content by the second paraffin content. The composition is highly stable in initial tack with less dependence on temperature before curing.

Rubber composition

A pnuematic tire having a cap tread and a base tread is defined in way of material as follows: (1) said cap tread is made of a rubber material in which 100 pts. wt. of rubber component comprising at least 50 pts. wt. of natural rubber and/or polyisoprene rubber, at most 50 pts. wt. of polybutadiene rubber containing at most 20% of 1,2-bonding units and at most 50 pts. wt. of styrene-butadiene copolymer rubber containing at most 30 wt % of bonded styrene is incorporated with 50 to 100 pts. wt. of carbon black and with a softener in an amount satisfying the inequality;

Pneumatic tire base-cap tread

A rubber composition comprising, in specific mixing ratios, rubber material consisting mainly of natural rubber and/or synthetic polyisoprene rubber, a cobalt salt of rosin, carbon black having specific iodine adsorbability and dibutyl phthalate absorbability, and sulphur.

Rubber compositions comprising (1) polyisoprene (2) cobalt salt of rosin

Rubber compositions containing relatively large amounts of benzoic acid or monohydroxy benzoic acid providing vulcanized rubber products having improved adhesion to metallic or fibrous materials and an improved chipping and cutting resistance. This is a continuation of application Ser. No. 588,047, filed June 18, 1975, now abandoned.

Rubber compositions with benzoic acid compounds

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Chigasaki, Japan

Kazuhiro Yamada