Abstract: A pneumatic tire having an air permeation prevention layer composed of a thin film of a resin composition including at least 20% by weight of a thermoplastic polyester elastomer comprised of a block copolymer of polybutylene terephthalate and polyoxyalkylene diimide diacid at a weight ratio of polybutylene terephthalate/polyoxyalkylene diimide diacid of 85/15 or less.

Abstract: A rubber composition containing a cross-linkable rubber component and a carbon black having silica adhered to the surface thereof and a silica surface-treated carbon black suitable for use in tire tread where the surface-treated carbon black has a nitrogen specific surface area (N.sub.2 SA) of 20 to 300 m.sup.2 /g, a ratio IA.sub.o /IA.sub.f of the adsorption amount of iodine (IA.sub.o) and the adsorption amount of iodine after treatment by hydrogen fluoride (IA.sub.f) of at least 0.30 but less than 1.0, and a ratio IA.sub.e /IA.sub.ef of the adsorption amount of iodine after extraction from a rubber compound (IA.sub.e) and the value of the same after treatment by hydrogen fluoride (IA.sub.ef) of at least 0.30 but less than 1.0.

Abstract: A rubber composition for the manufacture of automotive vehicle tires suitably as a bead filler therefor. The composition comprises specified proportions of carbonblack, a modified novolak phenolic resin, hexamethylenetetramine and a polymeric cardanol based on a starting rubber component such that the resulting rubber composition has a relatively low rigidity prior to vulcanization and a relatively high dynamic modulus after vulcanization.

Abstract: A rubber composition for coating steel cords, comprising a raw material rubber and, compounded therein, a methylolmelamine derivative and a product of a reaction of a cobalt salt of an organic acid with a metaboric acid ester, and a rubber product reinforced with rubber-coated steel cords comprising steel cords coated with the rubber composition.

Abstract: A radial tire for passenger cars constructed with a sidewall portion formed from a rubber composition having of a volume resistivity of not more than 10.sup.4 .OMEGA.cm. The composition is comprised essentially of a selected rubber and a selected carbon black of an electrically conductive type. The tire is highly resistant to staining with mud and dust while in running and also with dirt pickup during storage.

Abstract: A promoter for bonding between a rubber and a steel cord, which is represented by the following general formula (I): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or different from one another and each represents a monocarboxylic radical bonded to the adjacent Co atom through the oxygen atom which is adjacent to the carbonyl group in said monocarboxylic radical; a rubber composition containing the bonding promoter, and rubber products made from the rubber composition.