Bridgestone Sports Co., Ltd.

Dic Covestro Ppolymer Ltd

Katsunobu Mochizuki

Hiroyuki Nagasawa

Masahiro Yamabe

Akira Kimura

Toru Ogawana

Jun Shindo

Kanae Tajima

Atsushi Namba

Takashi Akutagawa

Naoki Shirakawa

In a golf ball having a core and a cover of one or more layer, the core is formed of a material molded under heat from a rubber composition containing This ball achieves both a lower spin rate and excellent durability while maintaining a high rebound.

Golf ball

A foam composition that includes a polymer material such as polyurethane or polyurea and a leachable water-soluble fine powder is provided. This composition can be used in a relatively simple process to obtain a foam body (porous body) that is uniform only at the surface or uniform throughout. The foam body can be suitably used as a golf ball member in golf balls required to have good controllability on approach shots. Also provided is a method for producing a foam member, which method includes the steps of molding the foam composition to obtain a solid molded body, and then leaching out and removing the water-soluble fine powder so as to obtain a foam-molded body.

Foam composition, foam member and method of manufacture

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a corea coverand an intermediate layertherebetween wherein the core is formed of a rubber composition that includes an alcohol having a value obtained by dividing the molecular weight of the alcohol by the number of hydroxyl groups thereon which is 70 or less. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

A resin composition for golf balls is made of (A) polyurethane or polyurea and (B) a styrene resin material, component (B) being included in an amount of 0.5 to 50 parts by weight per 100 parts by weight of component (A). In a golf ball having a core and a cover of one or more layer encasing the core, at least one cover layer is formed of this resin composition. The resin composition is especially useful as a golf ball cover material because the ball does not fly too far and is easier to control on approach shots, yet does not sacrifice distance on shots with a driver.

Resin composition for golf balls, and golf ball

A golf ball having a core and a cover that is formed of a resin composition which includes (A) a polyurethane or a polyurea and (B) a styrenic resin material, when dropped from a height of 3 m and made to collide with a metal plate, has velocities 200 ms before and 200 ms after contact that satisfy the condition: (incident velocity)&#x2212;(rebound velocity)&#x2265;0.80 m/s. The ball has a good controllability on approach shots without a loss in the distance achieved on shots with a driver, and thus is particularly useful to professional golfers and skilled amateurs.

A resin composition for golf balls includes specific amounts of (A) polyurethane or polyurea and (B) an oxazoline group-containing acrylic polymer or an oxazoline group-containing styrene polymer. A golf ball having a core encased by a cover of one or more layers, wherein at least one cover layer is formed of this resin composition, exhibits a good adhesion between adjoining layers, enabling the ball to achieve a high scuff resistance without lowering the initial velocity of the ball.

A resin composition for golf balls is made of (A) polyurethane or polyurea and (B) an acrylic resin or a methacrylic resin, component (B) being included in an amount of from 0.5 to 50 parts by weight per 100 parts by weight of component (A). In a golf ball having a core and a cover of one or more layer encasing the core, at least one cover layer is formed of this resin composition. The resin composition is especially useful as a golf ball cover material because it makes it possible to achieve a higher ball initial velocity on shots with a driver and a lower ball initial velocity on approach shots.

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core, a coverand an intermediate layertherebetween wherein the core is formed of a rubber composition that includes a lower alcohol having a molecular weight below 200. Also, letting Hc be the JIS-C hardness at the center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at the surface of the core, the core has a hardness profile in which these hardnesses satisfy fixed relationships defined by specific formulas.

The invention provides a golf ball having a core and a cover of one or more layer encasing the core, wherein, letting HU-A and HU-B be respectively the Martens hardnesses measured at positions 100 &#x3bc;m and 200 &#x3bc;m inward from a surface of an outermost layer of the cover and toward a center of the core, and letting HU-C be the Martens hardness measured at a position 100 &#x3bc;m from an inner side of the outermost cover layer and toward the surface, HU-A or HU-B is harder than HU-C.

In order to satisfy at a high level the golf ball flight and control performances relied on by professional golfers and skilled amateurs, this invention provides a multi-piece solid golf ball G having a core, a coverand an intermediate layertherebetween wherein, letting Hc be the JIS-C hardness at a center of the core, H12 be the JIS-C hardness at a position 12 mm from the core center and Ho be the JIS-C hardness at a surface of the core, the core has a hardness profile which satisfies the condition (Ho&#x2212;H12)&#x2212;(H12&#x2212;Hc)&#x2265;10; letting (Ho&#x2212;H12)&#x2212;(H12&#x2212;Hc) above be A, the spin index of the ball, defined as the dynamic coefficient of friction of the ball multiplied by A, is at least 3.0; and the hardness profile index, defined as the deflection (mm) of the core when compressed under a final load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf) multiplied by A, is at least 40.

In a golf ball having a core and a cover of one or more layer encasing the core, an outermost layer of the cover is molded of a thermoplastic material selected from the group consisting of polyurethane, polyurea and mixtures thereof, and the surface of the cover is treated with a polyisocyanate compound that is free of organic solvent. A method of manufacturing the golf ball is also described. Such golf balls are endowed with an excellent spin performance and scuff resistance, in addition to which productivity of the golf balls is high.

Golf ball and method of manufacture

The invention provides a method of manufacturing a golf ball having a core and a cover of one or more layer over the core, wherein an outermost layer of the cover is molded of a thermoplastic material selected from the group consisting of polyurethane, polyurea and mixtures thereof. The method includes at least the following steps (1) and (2):

Golf ball manufacturing method

A method of manufacturing golf balls having a core and a cover of at least one layer encasing the core includes, when molding the cover, blending a thermal antioxidant into the cover stock in a plurality of divided portions. This method is able to minimize deterioration and discoloration of the cover stock, enabling golf balls of stable quality to be obtained. In addition, it is able to facilitate the use of reclaimed material, enabling environmentally and economically efficient production to be carried out.

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Chichibushi, Japan

Katsunobu Mochizuki