Sumitomo Rubber Industries Limited

Sri Sports Limited

Hidenori Hiraoka

Yoshimasa Koizumi

Akihiko Hamada

Keiji Moriyama

Masatoshi Yokota

Kuniyasu Horiuchi

Satoshi Iwami

Yoshikazu Yabuki

Keiji Ohama

Kiyoto Maruoka

Akira Kato

Mikio Yamada

Kazushige Sugimoto

Koichi Fujisawa

Takeshi Asakura

Kazunari Yoshida

Yoshinobu Nakamura

Takumi Nishino

Katsutoshi Kitaoh

Hiroshi Ohtsuru

A method for manufacturing a golf ball by forming half shell covers using a rubber composition and forming golf ball covers using the half shell covers. The adhesion strength between the bonding surfaces of half shells (durability of golf balls) is improved by keeping the shape of half shells and the thickness of the resulting covers uniform. The adhesion strength between the bonding surfaces of half shells is further increased by using a composition containing a crystalline rubber as the rubber composition for cover; molding the rubber composition at a particular temperature while preserving the shape of the half shells without crosslinking or with only partially crosslinking the rubber component; and forming the half shells into a cover while crosslinking the rubber components.

Method for manufacturing golf ball

The present invention provides a multi-piece solid golf ball comprising a core consisting of an inner core and an outer core, and one or more layers of cover, wherein the inner core has a diameter of 30 to 39.5 mm and a center hardness in JIS-C hardness of 55 to 70, and is formed from press molded rubber composition comprising polybutadiene, a co-crosslinking agent, an organic peroxide and a filler, and the JIS-C hardness at a distance of 15 mm from the center point of the inner core is higher than the center hardness by 5 to 20; the outer core has a thickness of 0.3 to 2.0 mm and a surface hardness in JIS-C hardness of 75 to 90, and is formed from press molded rubber composition, and the surface hardness of the outer core is higher than the center hardness of the outer core is higher than the center hardness of the inner core by 10 to 35; and the cover contains thermoplastic resin as a base resin, and the outmost cover layer has a thickness of 1.5 to 2.5 mm and a surface hardness in Shore D hardness of 64 to 72.

Multi-piece solid golf ball and method of making the same

The present invention provides a three-piece solid golf ball having both excellent hit feeling and large flying distance. The three-piece solid golf ball comprises a core and a cover covering the core and the core has a two-layer structure comprising a center a and an outer shell b. The center a contains an &agr;,&bgr;-unsaturated carboxylic acid metallic salt in an amount of 13 to 28 parts by weight based on 100 parts by weight of a base rubber and the outer shell b contains an &agr;,&bgr;-unsaturated carboxylic acid metallic salt in an amount of 28 to 35 parts by weight based on 100 parts by weight of an base rubber. A surface hardness (measured by JIS-C type hardness tester) of the core is 75 to 88 and a compression deformation amount of the core is 2.7 to 5.0 mm.

Three-piece solid golf ball

A golf ball exhibits a high spin and easily comes to a halt even when shot from the rough or when shot in a raining condition. The cover material of the golf ball is based on ionomer resin. The cover material has 5-50 parts by weight of a tackifier such as terpene resins, rosin ester resins or the like blended with respect to 100 parts by weight of the base material.

Golf ball

A golf ball which produces high spin rate and accordingly readily stops even when being shot from a rough or in the rain is provided. Such a golf ball is constituted of a core and a cover and the cover has a loss tangent of 0.15 to 0.70 at &minus;10&deg; C. in a temperature distribution curve for dynamic viscoelasticity measured in a tensile mode under conditions of temperature increasing rate of 4&deg; C./min, frequency of 10 Hz and initial strain of 1.0 mm.

The present invention provides a colored golf ball having soft and good shot feel at the time of hitting, and having excellent discriminability when used in bad weather or the winter season because of its vivid and deep color tone. The present invention relates to a colored golf ball comprising a core having at least one layer and a cover having at least one layer formed on the core, wherein the outermost layer of the cover contains 3.0 to 7.0 parts by weight of fluorescent pigment and 0.05 to 0.5 parts by weight of titanium dioxide, the cover being coated with one or more layers of clear coating, and the surface of the golf ball having an L*-value of 50 to 80, measured using a color difference meter.

Colored golf ball

A rubber composition suitable for use in grips of articles such as golf clubs, tennis rackets, bicycles and tools, comprising (1) a rubber component containing an ethylene-propylene-diene rubber (EPDM), and (2) 5 to 100 parts by weight of a polyisobutylene having a viscosity average molecular weight of 6,000 to 50,000, which provides grips having good feeling of touch, good non-slipping properties in both fine and rainy weather, and giving a small feeling of impact to mis-shot of golf balls as compared with conventional grips.

Rubber composition for grips of articles containing EPDM and grip made

A multi piece solid golf ball comprising:

Multi-piece solid golf ball

Disclosed is a golf ball comprising a core 1 composed of a center 1a and an outer shell 1b, and a cover 2 covering said core 1, wherein a specific gravity of said center 1a is 0.2 to 1. The golf ball has excellent flying distance and satisfies other performances of golf balls.

A three-piece solid golf ball which attains a long flight distance with excellent controllability which comprises a core having a two-layer structure of a center and a shell covering the center, and a cover covering the core, wherein

A solid golf ball comprising a core and a cover, wherein the core has a trans structure content in polybutadiene of 10 to 30%. The core is produced by vulcanizing a rubber composition containing a butadiene rubber having cis structure content of not less than 90% before vulcanization, as a base rubber, wherein an amount of trans structure after vulcanization is 10 to 30% and a difference in hardness measured by a JIS-C type hardness tester between the center of the core and each point located from the center to the surface at an interval of 5 mm is not more than 10%. The rubber composition for forming the core comprises a vulcanizing agent, a filler, an organic peroxide and an organophosphorus compound, in addition to the butadiene rubber having cis structure content of not less than 90% before vulcanization.

Solid golf ball and process for producing the same

Two-piece golf ball

The present invention provides a three-piece solid golf ball having both excellent hit feeling and large flying distance. The three-piece solid golf ball comprises a core 1 and a cover 2 covering the core 1, and the core 1 has a two-layer structure comprising a center 1a and an outer shell 1b. The center 1a contains an .alpha.,.beta.-unsaturated carboxylic acid metallic salt in an amount of 13 to 28 parts by weight based on 100 parts by weight of a base rubber and the outer shell 1b contains an .alpha.,.beta.-unsaturated carboxylic acid metallic salt in an amount of 28 to 35 parts by weight based on 100 parts by weight of an base rubber. A surface hardness (measured by JIS-C type hardness tester) of the core 1 is 75 to 88 and a compression deformation amount of the core 1 is 2.7 to 5.0 mm.

The present invention provides a one-piece solid golf ball or a two or more piece solid golf ball which comprises an inner core and a cover covering the inner core. The one-piece solid golf ball is formed from a rubber composition which comprises:

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Kobe, Japan

Hidenori Hiraoka