Abstract: In heat-expandable microspheres as a starting material for hollow fine particles, which have excellent performances required for giving not only a durability in steady running region but also a durability in high-speed running region to a tire-rim assembly, and each consisting of an outer shell made of a thermoplastic resin obtained by polymerizing a monomer component in the presence of a polymerization initiator, and a foaming agent encapsulated in the outer shell and having a boiling point not higher than a softening point of the thermoplastic resin, the polymerization initiator comprises a peroxydicarbonate as an essential component, and the foaming agent comprises a fluorine-containing compound having an ether structure and a carbon number of 2-10 and containing no chlorine atom and bromine atom.

Abstract: In heat-expandable microspheres as a starting material for hollow fine particles, which have excellent performances required for giving not only a durability in steady running region but also a durability in high-speed running region to a tire-rim assembly, and each consisting of an outer shell made of a thermoplastic resin obtained by polymerizing a monomer component in the presence of a polymerization initiator, and a foaming agent encapsulated in the outer shell and having a boiling point not higher than a softening point of the thermoplastic resin, the polymerization initiator comprises a peroxydicarbonate as an essential component, and the foaming agent comprises a fluorine-containing compound having an ether structure and a carbon number of 2-10 and containing no chlorine atom and bromine atom.

Abstract: There is provided, in a tire/rim assembly, in which hollow particles are filled in a tire chamber, in order to reform the surface of the hollow particles and to prevent the hollow particles from adhering with each other, in applying coating to the surface of the hollow particles, a method for even distribution of the coating on the surface of the hollow particles and the robust fixing to the surface. In a tire/rim assembly constructed by assembling the tire onto the rim, arranging a number of thermally expandable hollow particles consisting of a continuous phase of a resin and a closed cell(s) in the assembly and filling high-pressure gas exceeding an atmosphere pressure in the tire chamber, at least a part of a surface of the hollow particles has a coating fixed by heating the surface.

Abstract: Hollow particle can be charged into a tire when a second stem is disconnected from a first stem in a tire valve of the present invention. When the second stem is fitted in the first stem, the hollow particle is sealed in the tire by a filter provided on the second stem and a gas can be charged into the tire through a valve core provided on the second stem.

Abstract: A pneumatic tire which comprises a pair of right and left bead portions, a carcass layer disposed extending between the bead portions, a tread portion arranged at an outside of the carcass layer in a radial direction of the tire, a pair of side wall portions arranged at right and left sides of the tread portion and at least one pair of rubber members selected from a pair of rubber members constituted with a rigid rubber and arranged in the bead portions and a pair of rubber members disposed in the side wall portions, wherein at least one pair of rubber members selected from a pair of rubber members arranged in the bead portions and a pair of rubber members disposed in the side wall portions are constituted with rubber composition having a minimum value of a dynamic storage modulus within a temperature range of 200 to 250° C. which is 75% of a dynamic storage modulus at 50° C. or more.

Abstract: Hollow particle can be charged into a tire when a second stem is disconnected from a first stem in a tire valve of the present invention. When the second stem is fitted in the first stem, the hollow particle is sealed in the tire by a filter provided on the second stem and a gas can be charged into the tire through a valve core provided on the second stem.

Abstract: There is provided a tire-rim assembly capable of stably running over a distance required even in the dropping of the tire internal pressure after the injuring of the tire without sacrificing rolling resistance and ride comfort in the usual running before the injuring of the tire, wherein a great number of substantially sphere-shaped particles each consisting of a continuous phase of a resin and a closed cell(s) and having a mean bulk specific gravity of not more than 0.1 are disposed in an interior defined by assembling a hollow doughnut-shaped tire onto an approved rim, and a pressure at 25° C. in the interior of the tire is not less than 150 kPa as an absolute pressure.

Abstract: A tire capable of stably running even if the tire is subjected to external injury without sacrificing rolling resistance and ride comfort in the usual running before being subjected to external injury, is provided. A composite body consists of a continuous phase of a resin and closed cells arranged in an inside of a hollow doughnut-shaped tire and the composite body has a cell content of 80.00 vol % to 98.75 vol %, and an internal pressure at 25° C. in the closed cell included therein is not less than 150 kPa as an absolute pressure.

Abstract: The present invention provides a rubber composition improved in the heat resistance, which is suitable for a reinforcing rubber for tire sidewall portions and a bead filler rubber. Also, provided is a pneumatic tire produced using the rubber composition.

Abstract: A pneumatic tire which comprises a pair of right and left bead portions, a carcass layer disposed extending between the bead portions, a tread portion arranged at an outside of the carcass layer in a radial direction of the tire, a pair of side wall portions arranged at right and left sides of the tread portion and at least one pair of rubber members selected from a pair of rubber members constituted with a rigid rubber and arranged in the bead portions and a pair of rubber members disposed in the side wall portions, wherein at least one pair of rubber members selected from a pair of rubber members arranged in the bead portions and a pair of rubber members disposed in the side wall portions are constituted with rubber composition having a minimum value of a dynamic storage modulus within a temperature range of 200 to 250° C. which is 75% of a dynamic storage modulus at 50° C. or more.

Abstract: A short fiber-reinforced rubber composition comprises a master batch (A) comprised of (a) a first diene-based elastomer, (b) a polyolefin having a melting point of 100-150° C. and (c) short fibers of a thermoplastic polymer having amide group in its main chain, and a second diene-based elastomer (B) kneaded with the master batch (A), in which an amount of the component (c) is 5-30 parts by weight based on 100 parts by weight in total of the first diene-based elastomer and the second diene-based elastomer. Further, a rubber sheet made of the short fiber-reinforced rubber composition is inserted in a given zone of the sidewall portion, whereby the stiffness of the sidewall portion is enhanced to simultaneously establish the steering stability and the ride comfort and reduce the rolling resistance.

Abstract: A pneumatic tire which is used for a vehicle and obtained after a rubber material is formed by vulcanization. A cap portion (12A), which is an upper layer of a tread and directly contacts the road surface, is a foam rubber which includes innumerable elongated closed cells (24). The outer portion of the elongated closed cell (24) is coated by a resinous protective layer (26). During the vulcanization process of the tire, a resin whose viscosity is lower than that of a rubber matrix and a blowing agent which generates gas are kneaded with a rubber material so as to obtain a rubber composition. The rubber composition is formed in the shape of a band and adhered to a crown portion of a raw tire casing. The resin is melted by the heat of vulcanization and the viscosity of the resin is lower than that of the rubber matrix. The gas generated in the rubber moves toward and concentrates at the inner side of the resin.

Abstract: There is a tire capable of stably running even if the tire is subjected to external injury without sacrificing rolling resistance and ride comfort in the usual running before being subjected to external injury, wherein a composite body consisting of a continuous phase of a resin and closed cells is arranged in an inside of a hollow doughnut-shaped tire and the composite body has a cell content of 80.00 vol % to 98.75 vol % and an internal pressure at 25° C. in the closed cell included therein is not less than 150 kPa as an absolute pressure.

Abstract: A foamed rubber composition for pneumatic tires comprises at least one diene polymer as a rubber ingredient and includes closed cells in a matrix rubber, each of these cells being covered with a coat layer made from a given amount of a resin or resin composite having a JIS-C hardness of not less than 75, a particle size of 10-200 .mu.m and a reacted conjugate diene unit content of not less than 10% by weight. In the production of the foamed rubber composition, the melting point or glass transition point of the resin or resin composite is restricted to at least 5.degree. C. lower than the vulcanizing temperature.

Abstract: A foamed rubber composition for tire comprises a particular amount of particles having specified hardness and average particle size and containing aluminum-bonded hydroxy group and/or silicon-bonded hydroxy group at its surface, and a particular amount of at least one specified silane coupling agent, and develops excellent performances on ice. Further, pneumatic tires contain the foamed rubber composition as a tread rubber.

Abstract: A foamed rubber composition for pneumatic tires comprises at least one diene polymer as a rubber ingredient and includes closed cells in a matrix rubber, each of these cells being covered with a coat layer made from a given amount of a resin or resin composite having a JIS-C hardness of not less than 75, a particle size of 10-200 .mu.m and a reacted conjugate diene unit content of not less than 10% by weight. In the production of the foamed rubber composition, the melting point or glass transition point of the resin or resin composite is restricted to at least 5.degree. C. lower than the vulcanizing temperature.

Abstract: A pneumatic tire for all seasons comprises a tread provided with a foamed rubber containing a given amount of a particular resin such as crystalline syndiotactic 1,2 -polybutadiene having specified hardness and average particle size, and having specified expansion ratio, average expanded cell size and storage modulus (E') at -20.degree. C. of a given range, and exhibits satisfactory braking and traction performances at not only dry-on-ice state but also wet-on-ice state while sufficiently holding the steering stability, durability and low fuel consumption in summer season.

Abstract: A rubber composition used for passenger car tire, particularly as bead filler thereof comprises particular amounts of carbon black and at least one resin obtained by adding amine as a curing agent for resin to a novolak type phenolic resin modified with at least one of animal oil, vegetable oil, unsaturated oil, aromatic hydrocarbon and nitrile rubber for the provision of self curability, based on 100 parts by weight of particular rubber component usually used in the tire.