Bridgestone Tire Company Limited

Toshiyuki Osaki

Kazuo Naito

Sakae Inoue

Suminobu Kurahashi

Kinji Masuda

Tsuneharu Akiyama

Motokazu Kikuchi

Hideo Nakauchi

Sakae Inouye

Norio Wada

Polyurethane products having improved flex crack resistance can be obtained by curing a mixture of (a) a polyurethane prepolymer having terminal isocyanate group and (b) at least one curative selected from polyamine and polyol to prepare a polyurethane product, and heat treating the polyurethane product at a temperature of 60.degree.-180.degree. C for 1-30,000 minutes under an atmosphere having an absolute humidity of at least 2%.

Method of producing polyurethane products having an improved flex crack

This invention relates to an improvement of the adhesion of a metallic material such as copper, copper alloys and other metals coated therewith with a vulcanizable rubber composition. It is realized by previously adding orthoboric acid or a metal borate to the rubber composition in order to proceed with metal-rubber bonding reaction and vulcanization reaction in good balance, and vulcanizing an assembly of the metallic material and the boric compound containing rubber composition closely contacted therewith.

Method for improving adhesion of metallic material with vulcanizable

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Higashimurayama, Japan

Toshiyuki Osaki