Golf ball
AssigneeBridgestone Sports Co., Ltd.
InventorsKae IIZUKA, Eiji TAKEHANA
Life of this patent
Estimating the term…
Abstract
The invention provides a golf ball in which an intermediate layer formed of a highly neutralized resin mixture obtained by using two nonionic resins of differing weight-average molecular weights and breadths of molecular weight distribution (weight-average molecular weight/number-average molecular weight) as the base resin and adding thereto an organic acid or a metal salt thereof and a basic inorganic metal compound capable of being neutralized is combined with a cover formed of an ionic resin having a weight-average molecular weight in a specific range and a breadth of molecular weight distribution (weight-average molecular weight/number-average molecular weight) in a specific range. The golf ball material of the invention has an excellent rebound and durability.
Claims4
A golf ball comprising a core, one or more intermediate layer and an outermost cover layer, wherein at least one intermediate layer is formed of a resin composition which is comprised of:
- (a) a nonionic olefin-unsaturated carboxylic acid copolymer and/or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 40,000 to 200,000, a weight-average molecular weight (Mw)/number-average molecular weight (Mn) ratio of from 2.0 to 10.0 and an unsaturated carboxylic acid content of at least 16 wt %,
- (b) a nonionic olefin-unsaturated carboxylic acid copolymer and/or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 40,000 to 200,000, a weight-average molecular weight (Mw)/number-average molecular weight (Mn) ratio of from 4.0 to 10.0 and an unsaturated carboxylic acid content of less than 16 wt %,
- (c) an organic acid or a metal salt thereof, and
- (d) a basic inorganic metal compound for neutralizing at least 70 mol % of acid groups in components (a) to (c), and which has a material hardness, expressed as the Shore D hardness, of from 40 to 60;
- and wherein the cover is formed of a resin composition which is comprised of:
- (A) an ionic olefin-unsaturated carboxylic acid copolymer and/or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 40,000 to 200,000, a weight-average molecular weight (Mw)/number-average molecular weight (Mn) ratio of from 4.0 to 10.0 and an unsaturated carboxylic acid content of at least 16 wt %, and/or
- (B) an ionic olefin-unsaturated carboxylic acid copolymer and/or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer having a weight-average molecular weight (Mw) of from 40,000 to 200,000, a weight-average molecular weight (Mw)/number-average molecular weight (Mn) of from 4.0 to 10.0 and an unsaturated carboxylic acid content of less than 16 wt %, and which has a material hardness, expressed as the Shore D hardness, of at least 55.
Dependencies are inferred from the claim text.