Bridgestone Sports Co., Ltd.

Kae Yamazaki

Eiji Takehana

Jun Shindo

Yoshinori Egashira

Tsuyoshi Nakajima

Yuichiro Ozawa

The invention provides a golf ball having a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition containing (A) a base rubber, (B) an organic peroxide, and (C) water and/or a metal monocarboxylate, and has a hysteresis loss of 50% or less when compressed at a load cell speed of 500 mm/min and under a constant load of 5,000 N.

Golf ball

The present invention provides a golf ball material made of an ionomer blend composition of (a) at least one E/X copolymer and/or E/X/Y terpolymer and (b) at least one polyfunctional higher aliphatic acid with two or more functionalities that has a molecular weight of at least about 200 but less than about 1,500, in which components (a) and (b) are neutralized with (c) an oxygen-containing inorganic metal compound. The copolymer and terpolymer of component (a) is one or a mixture of two or more selected from the group consisting of copolymers and terpolymers which is partially neutralized with metal ions, copolymers and terpolymers which are completely neutralized with metal ions, and unneutralized copolymers and terpolymers. The golf ball material has a good thermal stability, flow properties and moldability, making it suitable for injection molding. The material is ideal for forming high-performance golf balls of excellent durability, scuff resistance and optimal hardness, without any loss in the rebound resilience of moldings obtained therefrom.

Golf ball material, golf ball, and method for preparing golf ball material

The present invention provides a golf ball having a core and a cover of one or more layer, wherein the core is made of a material obtained by molding under heat a rubber composition which includes (a) a base rubber containing polybutadiene having a stress relaxation time (T) of 3.5 or less, (b) an unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide, and wherein at least one layer of the cover is made of a material obtained by molding a mixture containing as the essential ingredients (A) a metal ion neutralized olefin-unsaturated carboxylic acid random copolymer having a Shore D hardness of at least 60, (B) an unsaturated fatty acid, and (C) a basic inorganic metal compound capable of neutralizing acid groups in components A and B. The golf ball has a good rebound, a good feel on impact, and excellent scuff resistance.

The present invention provides a golf ball material which is a thermoplastic ionomer blend composition of an acid-containing ethylene-based terpolymer having a weight-average molecular weight Mw of at least about 100,000, an acid-containing ethylene-based copolymer and/or terpolymer having a Mw of about 1,500 to about 95,000, and a low-molecular-weight acid-containing compound having a molecular weight of up to about 1,000, at least some portion of which composition is neutralized. The golf ball material is soft and resilient, and has a good durability and improved moldability.

Golf ball material and golf ball

The present invention provides a golf ball having a core and a cover of one or more layer, wherein the core is made of a material obtained by molding under heat a rubber composition which includes (a) a base rubber containing polybutadiene having a stress relaxation time (T) of 3.5 or less, (b) an unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide, and wherein at least one layer of the cover is made of a material obtained by molding a mixture composed of (A) 100 parts by weight of a base resin and (B) 1 to 40 parts by weight of a branched saturated fatty acid or a derivative thereof. The golf ball has an excellent rebound overall, a soft, pleasant feel on impact, and excellent scuff resistance. Moreover, it has an appearance with a high degree of whiteness.

The present invention provides a polymer composition which includes (A) an olefin-unsaturated carboxylic acid random copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer, (D) a metal ion neutralization product of an olefin-unsaturated carboxylic acid random copolymer and/or a metal ion neutralization product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer, or both components A and D, and also includes a specific amount of (B) a metal oxide which is capable of neutralizing acid groups in components A and/or D, and which is produced by plasma synthesis, laser synthesis or flame synthesis and has an average particle diameter of at most 200 nm. The invention also provides golf balls in which such a polymer composition serves as a component of the ball. The polymer composition is ionically bonded and has an excellent resilience. Golf balls made using the polymer composition have an outstanding rebound.

Polymer composition and golf ball made using the same

The present invention provides a golf ball having a core and a cover of one or more layer. The core is made of a material obtained by molding under heat a rubber composition containing (a) polybutadiene having a stress relaxation time (T) of 3.5 or less, (b) an unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide. A least one layer of the cover is made of a heated mixture which includes (A) an olefin-unsaturated carboxylic acid random copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer, (B) a fatty acid having a molecular weight of at least 280 or a derivative thereof, and (C) a basic inorganic metal compound capable of neutralizing acid groups in components A and B. The golf ball can be efficiently manufactured, and synergistic effects between the core material and the cover material enhance the rebound of the ball.

The present invention provides a golf ball having a core, an outermost cover layer and an intermediate layer therebetween. The core is made of a material obtained by molding under heat a rubber composition containing polybutadiene having a stress relaxation time (T) of 3.5 or less. The intermediate layer, which is of a specific thickness, is made primarily of a resin material of a specific hardness obtained by blending together (I) a sodium ion neutralization product of an olefin-unsaturated carboxylic acid random copolymer with (II) a magnesium ion neutralization product of an olefin-unsaturated carboxylic acid random copolymer. The outermost cover layer, which is of a specific thickness, is made primarily of a non-ionomeric resin material of a specific hardness. The golf ball has an excellent rebound, a good feel on impact, and an excellent scuff resistance.

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Chichibu, Japan

Kae Yamazaki