Bridgestone Tire Company Limited

Shiro Anzai

Ryota Fujio

Yoji Watabe

Nobuyuki Kataoka

Hiroshi Kaneda

Michio Ishii

Yasuyuki Ura

Yoshihide Fukabori

Motozumi Kitayama

Yoshihide Fukahori

Junji Furukawa

Yutaka Iseda

Takuya Takahashi

Fujio Ohkawa

Fumio Odaka

Yoshihiko Fujii

Takashi Nyomura

Akio Souma

Fumitaka Ino

Takeshi Kimura

Masao Kuwano

Nobuyuki Katacka

A method of preparing a nitrile rubber composition having modulus and excellent physical properties and abrasion resistance is disclosed. This composition is prepared by kneading at 120.degree.-160.degree. C. (a) a nitrile rubber, (b) an .alpha.,.beta.-ethylenically unsaturated carboxylic acid, (c) a divalent metal compound, (d) a secondary aryl amine, cooling the kneaded mass below 100.degree. C., adding to the kneaded mass (e) an organic peroxide, and heating and curing the resulting mixture at 110.degree.-180.degree. C. The addition of the secondary aryl amine considerably improves the physical properties of the composition. These compositions have not a tendency of scorching and are superior in the workability as compared with conventional carboxylated nitrile rubber compositions produced by emulsion polymerization.

Nitrile rubber composition having high modulus

Tire filling material having high resilience produced by curing a mixture of

Polyurethane tire filling material with plasticizer incorporated therein

Scrap vulcanized rubber is reclaimed by mixing with a reclaiming agent selected from (a) 1,8-diazabicyclo-[5,4,0]-undecene-7, (DBU) (b) phenol salts of DBU, (c) carboxylic acid salts of DBU, (d) thiuramsulfide compounds, (e) aromatic disulfides, and (f) benzene sulfinic acid compounds or benzene sulfonyl hydrazides, provided that (e) aromatic disulfides are not used alone. Aliphatic or alicyclic amines may be used together with a compound selected from compounds (a)-(f) to enhance the reclaiming effect.

Process for reclaiming scrap vulcanized rubber

Novel abrasion resistant rubber compositions are disclosed. The compositions are prepared by curing the mixtures comprising a diene elastomer, an .alpha.,.beta.-ethylenically unsaturated carboxylic acid, a divalent metal compound, and an organic peroxide. When an unpolymerizable carboxylic acid is added to the mixture, the mechanical properties of the composition are improved. The addition of a carbon black to the mixtures brings about the improvement of weather-proofing property of the composition. The compositions are useful for the rubber stock of solid tires, snow removing plates and the like.

Abrasion resistant rubber compositions

Two-piece solid golf balls having an improved initial velocity are disclosed. The core is obtained by curing a composition comprising (a) 100 parts by weight of polybutadiene, (b) 9-20 parts by weight of a polyfunctional unsaturated ester, (c) 5-10 parts by weight of methacrylic acid and/or acrylic acid, the total amount of the ingredients (b) and (c) being 15-30 parts by weight and the weight ratio of the ingredient (b)/the ingredient (c) being 55/45-80/20, (d) 20-80 parts by weight of a zinc compound and (e) 0.5-5 parts by weight of an alkyl peroxide. The cover comprises (f) 100 parts by weight of a metal salt of a copolymer of ethylene and unsaturated carboxylic acid, said metal salt having a loss tangent of lower than 0.08, and (g) 1-5 parts by weight of an inorganic filler.

Two-piece solid golf balls

A soft polyurethane elastomer containing isocyanurate ring prepared by reacting polyoxypropylene polyol having an OH equivalent molecular weight of about 500-3,000, and a functionality of about 2-5, and polyisocyanate compound in the presence of tertiary amine catalyst, and if desired further combined with organic tin catalyst. This process is advantageous in facilitation of material control during curing reaction, low exothermicity and high thermal stability of the resulting polymer. Further the properties of the polymer are improved by using ethyleneoxide addition polyoxypropylene polyol instead of the above polymer and a specific tertiary amine as a catalyst. The elastomer thus prepared is significantly suitable for tire filling material.

Soft polyurethane elastomer containing isocyanurate ring

Reinforced rubber composites having high Young's modulus and tear energy and a highly improved creep strength are produced by melt-blending 100 parts by weight of a natural or synthetic rubber, 5-150 parts by weight of N-methoxymethylated nylon (degree of N-methoxymethylation: 10-40 mol%) in the presence of or in the absence of a filler and an antioxidant in Banbury mixer, mixing thereto 5-20 parts by weight based on 100 parts of said nylon, of a higher saturated aliphatic monobasic organic acid which is a cross-linking agent for N-methoxymethylated nylon, 0.5-20 parts by weight based on 100 parts of the rubber, of a cross-linking agent for rubber and an appropriate amount of compounding agents and simultaneously cross-linking the rubber and the N-methoxymethylated nylon.

Rubber with organic acid and methoxy methyl nylon, sulfur vulcanized

One shot mouldable and curable homogeneous rubber composition consisting mainly of polyisoprene rubber and a monomer mixture composed of divinylbenzene and .alpha.-methylstyrene in specifically limited weight ratios of the rubber/the monomer mixture and of divinylbenzene/.alpha.-methylstyrene and containing small amounts of organic peroxide and at least one of amine compound and phenol compound. The cured product of the rubber composition has high Young's modulus, tear energy and tensile strength retention. More improved cured rubbers having these physical properties well balanced in a high level can be easily obtained by additionally adding a small amount of sulfur or p-quinonedioxime to the above rubber composition.

Rubber compositions of polyisoprene .alpha.-methylstyrene,

An ethylene-propylene copolymer rubber composition having a high Young's modulus, which comprises 100 parts by weight of a mixture of the following ingredients (a) and (b) in a weight ratio of ingredient (a)/ingredient (b) of 67/33-50/50, said ingredient (a) being an ethylene-propylene copolymer having a Mooney viscosity of at least 75, said ingredient (b) being divinylbenzene, (c) 0.3-2.5 parts by weight of an organic peroxide, and (d) 0.01-0.25 part by weight of sulfur, and the homogeneous rubber composition cured at 120.degree.-180.degree.C having a Young's modulus of 200-500 Kg/cm.sup.2, a tensile strength of at least 200 Kg/cm.sup.2, an elongation of at least 300%, a tear energy of at least 10 Kg/cm and retentions of Young's modulus and tensile strength at 70.degree.C of at least 50%.

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Murayama, Japan

Shiro Anzai