Sumitomo Rubber Industries Limited

Kouhei Takemura

Masaya Tsunoda

Akihiro Nakahara

Jun Ochi

Masahide Onuki

Yoshinori Sano

Masahiko Ueda

Akihiko Hamada

Hiroaki Tanaka

Tetsuo Yamaguchi

Seigou Sakagami

A golf ball ( ) comprises a core ( ) and a cover ( ). The core ( ) has a six-layer structure having first to sixth layers ( ) to ( ). A value of (T /T ) is greater than 2.10 and is equal to or smaller than 2.50, wherein time series data on force in a z direction which is applied to a load cell provided on a back face of a collision plate inclined by 22 degrees with respect to a horizontal direction when the golf ball ( ) impacts the collision plate at a speed of 35 m/s in a vertically upward direction are represented by Fn(t), time series data on force in an x direction are represented by Ft(t), a time taken after a start of the impact before the Fn(t) is first changed from a positive number to zero is represented by T and a time taken after the start of the impact before the Ft(t) is first changed from a positive number to a negative number is represented by T . The golf ball ( ) has a higher back spin rate during hitting on the same conditions than that of a conventional golf ball.

Golf ball

A multi-piece solid golf ball has rebound characteristics equal to conventional two-piece solid golf ball when hitting at high head speed, and better rebound characteristics when hitting at low head speed. This multi-piece solid golf ball has a core with an inner layer outer layer on the inner layer, and at least one layer of cover on the core, the inner layer core having an elastic modulus of 50 to 200 MPa, the outer layer core having at least one layer of low elastic modulus with elastic modulus lower than the inner layer core by 15 to 100 MPa; at least one layer of the lowest elastic modulus layer in the core has a total thickness of 0.2 to 5.0 mm and is placed from 6.5 to 20.5 mm away from the core center point with diameter 37 to 41 mm.

Multi-piece solid golf ball

Disclosed is a thermoplastic elastomer composition having characteristics of both thermoplastic resin and rubber, and a golf ball using the thermoplastic elastomer composition as the cover. The thermoplastic elastomer composition of the present invention comprises a thermoplastic resin and crosslinked diene rubber particles having an average diameter of not more than 10 .mu.m dispersed in the thermoplastic resin, which is prepared by dynamic crosslinking diene rubber dispersed in the thermoplastic resin with crosslinking agent.

Thermoplastic elastomer composition, process for producing the same and

The present invention provides a golf ball having good shot feel and controllability and showing excellent rebound characteristics to give long flight distance. The golf ball of the present invention includes a core and a cover present on the core, an intermediate layer optionally being present between the core and the cover, wherein at least one layer of the cover or the intermediate layer has a thickness of 1 to 3 mm and is formed from a composition having an elasticity modulus (E*) at -30.degree. to +20.degree. C. of 1,000 to 9,000 Kgf/cm.sup.2 and a loss tangent at -30.degree. to +20.degree. C. of 0.02 to 0.1., and the core, whether solid core or thread wound core, has a spring constant at compression deformation of 15 to 60 Kgf/mm. The present invention also provides in another embodiment a three piece solid golf ball which includes a solid core, an intermediate layer formed on the solid core and a cover covering the intermediate layer, wherein the cover is formed from a mixture of an ionomer resin and a diene rubber, has a thickness of 1 to 3 mm, and is formed from a cover composition having an elasticity modulus (E*) at -30.degree. to +20.degree. C. of 1,000 to 9,000 Kgf/cm.sup.2 and a loss tangent at -30.degree. to +20.degree. C. of 0.02 to 0.1; the intermediate layer has a thickness of 1 to 3 mm and is formed from a resin composition having an elasticity modulus (E*) at -30.degree. to +20.degree. C. of 5,000 to 20,000 kgf/cm.sup.2 and a loss tangent at -30.degree. to +20.degree. C. of 0.15 or less, the minimum value of the elasticity modulus of the intermediate layer being larger than that of the cover; and the solid core has a diameter of 30.7 to 38.7 mm and a spring constant at compression deformation of 20 to 55 Kgf/mm.

The present invention provides a solid golf ball which is superior in shot feel and attains long flight distance. The solid golf ball comprises a core and a cover covering the core, wherein the core is prepared by vulcanizing a rubber composition comprising a base rubber obtained by mixing silicone rubber and a diene rubber under conditions wherein crosslinking of the diene rubber does not occur but crosslinking of the silicone rubber does occur, and wherein the mixing ratio of silicone rubber to the diene rubber is within the range of 5:95 to 45:55 by weight.

Solid golf ball

The present invention provides a golf ball having small impact force when hitting, good shot feel and excellent flight performances. The solid golf ball of the present invention comprises a core and a cover covering the core, wherein the core is obtained from a rubber composition comprising 100 parts by weight of cis-1,4-polybutadiene and 10 to 25 parts by weight of a metal salt of an unsaturated carboxylic acid, the core has a deformation of 3.5 to 6.5 mm when a weight load from an initial loading of 10 kg to a final loading 130 kg is applied to the core, and the cover has a stiffness modulus of 4,500 to 6,000 kg/cm.sup.2 at 23.degree. C. and a thickness of 3.2 to 5 mm.

Growing community of inventors

Nara, Japan

Kouhei Takemura