Bridgestone Sports Co., Ltd.

Yasushi Ichikawa

Rinya Takesue

Hisashi Yamagishi

Hiroshi Higuchi

Shunichi Kashiwagi

Junji Hayashi

Yasumasa Shimizu

Hideo Watanabe

Junji Umezawa

Hirotaka Shimosaka

Yoshinori Egashira

Eiji Takehana

Akira Kawata

Kunitoshi Ishihara

Nobuhiko Matsumura

Shinichi Kakiuchi

Atsushi Nakamura

Atsuki Kasashima

Hiroyuki Nagasawa

Yutaka Masutani

Takashi Maruko

Yoko Furuta

Keisuke Ihara

Jun Shindo

Michio Inoue

Atuki Kasasima

Hiroto Sasaki

Toshimi Yamanaka

Nobuhiko Sato

Shinich Kakiuchi

A multi-piece solid golf ball comprises a core having a 5 structure consisting of at least two layers and a cover on the core consisting of outer and inner cover layers. The outer cover layer has a Shore D hardness of 40-60 degrees. The inner cover layer has a Shore D hardness of up to 53 degrees and lower than that of the outer cover layer. The ball's carry is comparable to conventional solid golf balls and spin receptivity is approximate to wound golf balls while the ball is durable and offers pleasant feel.

Multi-piece solid golf ball

A multi-piece solid golf ball comprises a core having a structure consisting of at least two layers and a cover on the core consisting of outer and inner cover layers. The core has a diameter in the range of 35 to 41 mm. The inner sphere of the core is formed of a rubber material based on polybutadiene and an outer layer is formed of a thermoplastic or rubber based material. The outer cover layer has a Shore D hardness of up to 53 degrees and lower than that of the outer cover layer. The ball's carry is comparable to conventional solid golf balls and spin receptivity is approximate to wound golf balls while the ball is durable and offers pleasant feel.

In a multi-piece solid golf ball comprising a solid core, a mantle and a cover, the solid core is made of a rubber composition that includes a base rubber containing a polybutadiene synthesized using a rare-earth catalyst, a small amount of organic peroxide, an unsaturated carboxylic acid and/or a metal salt thereof, an organic sulfur compound and an inorganic filler. The mantle is made of a thermoplastic resin composition. The cover is made primarily of a thermoplastic polyurethane material. This construction provides the golf ball with a combination of outstanding flight performance and soft feel with cover's scuff resistance and coating's abrasion resistance, that is unprecedented.

A golf ball material comprises a heated mixture having a melt index of at least 1.0 dg/min, which mixture is composed of (A) a thermoplastic resin, (B) a fatty acid or fatty acid derivative having a molecular weight of at least 280, and (C) a basic inorganic metal compound capable of neutralizing acidic groups in components A and B. The material including a highly neutralized ionomer resin has good thermal stability, flow characteristics and moldability. The invention is also directed at high-rebound golf balls which can be easily and efficiently manufactured using the same material.

Golf ball materials and golf ball

A multi-piece golf ball includes a core 30&#x2013;40 mm in diameter, an intermediate layer including an outermost layer 0.5&#x2013;2.0 mm thick, and a cover 0.5&#x2013;2.0 mm thick. The core is a rubber composition mainly containing polybutadiene. The outermost layer is a resin material containing an ionomer resin in an amount of 30% by weight or more. The cover material is obtained by dispersedly blending a silicone powder in a main resin containing an ionomer resin in an amount of 50% by weight or more. The hardness of the outermost layer is harder than the hardness of the core's a center portion. The hardness of the cover is harder than the hardness of the outermost layer. A difference in hardness between the cover and the center portion of the core satisfies a relation of 10&#x2266;(Durometer D hardness of cover&#x2212;Durometer D hardness of center portion of core&#x2266;40.

Multi-piece golf ball

A golf ball material comprising a heated mixture of (a) a random copolymer containing at least 5% by weight of a metal ion-neutralized unsaturated carboxylic acid having an acid content of at least 16% by weight, (b) a thermoplastic elastomer, (c) a fatty acid and/or derivative thereof having a molecular weight of 280&#x2013;1,500, and (d) a basic metal compound capable of neutralizing unneutralized acid groups in components (a) and (c) has good thermal stability, flow and moldability, and can be molded into a part exhibiting excellent rebound, ensuring the manufacture of golf balls with high performance.

Golf ball material and golf ball

In a golf ball comprising a core and a cover of one or more layers, the cover or its layer is formed primarily of a mixture comprising a blend of (a) an ionomer resin in the form of an alkali metal-neutralized ethylene-acrylic acid copolymer and (b) an olefin-unsaturated carboxylic acid copolymer or an olefin-unsaturated carboxylic acid-unsaturated carboxylate copolymer, and (c) a thermoplastic elastomer. The golf ball exhibits good surface finish and has improved rebound, feel and durability.

Golf ball

A layer of a golf ball is formed of a golf ball-forming composition in which a silicone rubber powder, silicone resin powder or composite powder thereof is blended in an elastomer, resin or butadiene rubber base. The composition is easy to remove from a mold after molding, and the golf ball has advantages including high durability against consecutive strikes, and good feel and rebound even at low temperature.

A golf ball comprising a core and two or more outer layers covering said core, wherein the first outer layer is formed mainly from a mixture of a non-ionomer thermoplastic elastomer and an isocyanate compound and the second outer layer is formed mainly from a mixture composed of a resin component consisting of an ionomer resin and a non-ionomer thermoplastic elastomer, a fatty acid and/or a derivative thereof, a metal ion source capable of neutralizing unneutralized acid radicals in the above-mentioned components, and a compound having two or more reactive functional groups and a molecular weight no larger than 20,000, with the first outer layer being contiguous to the second outer layer, which exhibits superior in durability and rebound resilience.

A multi-piece golf ball includes a core having a diameter of 30 to 40 mm, at least one intermediate layer including the outermost layer having a thickness of 0.5 to 2.0 mm, and a cover having a thickness of 1.0 to 3.0 mm. The cover is made from a material obtained by dispersedly blending at least one kind of silicone powder selected from a silicone rubber powder, a silicon resin powder, and a composite powder thereof, in a main resin component containing an ionomer resin in an amount of 50% by weight or more. Dimples of the number of 300 to 550 pieces are formed in the surface of the golf ball in such a manner that a dimple total volume ratio VR is in a range of 0.85% or less. The multi-piece golf ball is excellent in resilience, flight distance characteristic, and feel of hitting.

In a golf ball comprising an elastic core, an intermediate layer of at least one layer, and a cover which is provided on its surface with a plurality of dimples, wherein the cover has a gage of 1.0&#x2013;1.5 mm, the intermediate layer has a gage of 1.0&#x2013;2.0 mm per layer, the golf ball in its entirety has a specific gravity of 1.128&#x2013;1.145 g/cm. On account of an optimum specific gravity in a relatively high range, the ball is improved in flight performance.

In a golf ball comprising a core and a cover of plural layers, a cover inner layer is formed primarily of an ionomer resin in admixture with a compound containing at least two reactive functional groups and having a molecular weight of up to 20,000 and a cover outer layer is formed primarily of a non-ionomer resin. The ball is fully durable to repeated impact, and maintains good spin performance, rebound characteristics and feel even after repeated impact.

A multi-piece solid golf ball has a solid core obtained by molding and vulcanizing a rubber composition which includes (A) a base rubber containing a polybutadiene synthesized using a rare-earth catalyst, (B) an unsaturated carboxylic acid and/or a metal salt thereof, (C) an organic sulfur compound, (D) an inorganic filler and (E) an organic peroxide. The core is enclosed within a mantle of one or more layer which is made primarily of a thermoplastic resin and has a Durometer D hardness of 30 to 70. The mantle is enclosed within a cover which is made primarily of a thermoplastic polyurethane and which has a Durometer D hardness of 40 to 60 that is lower than the Durometer D hardness of the outermost layer of the mantle. This construction provides the golf ball with an outstanding rebound.

Disclosed is a two-piece solid golf ball satisfying the following conditions (1) to (4):

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Chichibu, Japan

Yasushi Ichikawa