Golf ball

摘要

The present invention provides a golf ball which includes (I) a first member composed of a material molded under heat from a rubber composition of (a) a base rubber composed primarily of a mixture of at least 60 wt % of a polybutadiene having a stress relaxation time (T80), as defined below, of less than 4 seconds and up to 40 wt % of a polybutadiene having a stress relaxation time (T80) of at least 4 seconds, (b) an unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide; and (II) a second member composed of a specific, highly-neutralized, resin composition. The golf ball of the invention, by being thus constituted, has an excellent resilience for the ball as a whole, a good, soft, feel on impact, and imparts an excellent spin performance, thereby enabling an increased distance to be achieved. In addition, it has a high manufacturability.

主权项

1. A golf ball comprising a plurality of members which include:
(I) a first member comprised of a material molded under heat from a rubber composition comprising (a) a base rubber composed primarily of a mixture of at least 60 wt % of a polybutadiene having a stress relaxation time (T80), defined as the length of time it takes from the moment rotor rotation is stopped immediately after measurement of the ML1+4 (100° C.) value (the Mooney viscosity measured at 100° C. in accordance with ASTM D-1646-96) for the ML1+4 value to decrease 80%, of less than 4 seconds and up to 40 wt % of a polybutadiene having a stress relaxation time (T80) of at least 4 seconds, (b) an unsaturated carboxylic acid and/or a metal salt thereof, and (c) an organic peroxide; and (II) a second member formed primarily of a resin composition obtained by mixing
100 parts by weight of a base resin composed primarily of (A-I) an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random terpolymer and/or a metal salt thereof, and/or (A-II) an olefin-unsaturated carboxylic acid random copolymer and/or a metal salt thereof,(B) from 100 to 170 parts by weight of a fatty acid or fatty acid ester having a molecular weight of from 280 to 1500, and(C) from 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acid groups in components A and B, wherein (i) the olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester random terpolymer and/or a metal salt thereof serving as component A-I has a weight-average molecular weight (Mw) of at least 100,000 but not more than 200,000, and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of at least 3 but not more than 7.0, and (ii) the olefin-unsaturated carboxylic acid random copolymer and/or a metal salt thereof serving as component A-II has a weight-average molecular weight (Mw) of at least 150,000 but not more than 200,000, and a weight-average molecular weight (Mw) to number-average molecular weight (Mn) ratio of at least 3 but not more than 7.0.