Patent ID: 7625301
Filing Date: 2009-12-01
Classification: A63B

Abstract:
1. A golf ball comprising a core, an intermediate layer which encases the core, and a cover which encases the intermediate layer, wherein the core has a diameter of between 36 and 40 mm and a deflection of between 3.5 and 4.2 mm, the intermediate layer has a Shore D hardness of between 45 and 55 and a thickness of between 0.6 and 1.6 mm, the cover has a Shore D hardness of between 63 and 66 and a thickness of between 0.6 and 1.6, the ball as a whole has a deflection of between 2.6 and 3.5 mm, the intermediate layer and cover have a combined thickness of between 1.8 and 2.8 mm, the ball has a hardness design such that the Shore D hardnesses of the ball components satisfy the relationship the cover is made of a material composed primarily of a thermoplastic resin or a thermoplastic elastomer, and the intermediate layer is made of a material that is a resin composition containing a heated mixture which has a melt flow rate according to JIS K-7210 of 0.5 to 1.0 g/l 0 mm and which is selected from among (I) to (III) below: (a) 100 parts by weight of an olefin-unsaturated carboxylic acid random copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer, (b) from 5 to 80 parts by weight of a fatty acid or fatty acid derivative having a molecular weight of at least 280, and (c) from 0.1 to 20 parts by weight of a basic inorganic metal compound capable of neutralizing the acid groups in components (a) and (b); (d) 100 parts by weight of 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, (b) from 5 to 80 parts by weight of a fatty acid or fatty acid derivative having a molecular weight of at least 280, and (c) from 0.1 to 20 parts by weight of a basic inorganic metal compound capable of neutralizing the acid groups in components (d) and (b); 100 parts by weight of, in admixture, (a) an olefin-unsaturated carboxylic acid random copolymer and/or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random copolymer and (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, (b) from 5 to 80 parts by weight of a fatty acid and/or fatty acid derivative having a molecular weight of at least 280, and (c) from 0.1 to 20 parts by weight of a basic inorganic metal compound capable of neutralizing the acid groups in components (a), (d) and (b); at least 90% of the acid groups in the resin composition being neutralized, wherein the cover material and the intermediate layer material have a melt flow rate difference therebetween of at least 1.0 g/l 0 mm.