Golf ball material and golf ball

Abstract

A mixture having good thermal stability, flow and moldability and suitable as a golf ball-forming material is obtained when a base resin comprising a (metal ion-neutralized) olefin-unsaturated carboxylic acid-unsaturated carboxylate ternary random copolymer and optionally a (metal ion-neutralized) olefin-unsaturated carboxylic acid binary random copolymer is blended with specific proportions of a fatty acid and / or fatty acid derivative and a basic inorganic metal compound capable of neutralizing acidic groups left unneutralized in the base resin and fatty acid. Using the same material, high-rebound golf balls can be effectively manufactured.

Description

[0001] The present invention relates to golf ball materials which have good thermal stability, flow characteristics and moldability, and which are capable of providing high-performance golf balls endowed with outstanding rebound energy. The invention relates also to golf balls made with such golf ball materials. BACKGROUND OF THE INVENTION [0002] Over the past few years, wide use has been made of ionomer resins in golf ball cover materials, also referred to hereinafter as “cover stock”. Ionomer resins are ionic copolymers composed of an olefin such as ethylene in combination with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid or maleic acid, wherein the acidic groups are partially neutralized with metal ions such as sodium, lithium, zinc or magnesium ions. They have excellent characteristics such as durability, resilience and scuff resistance. [0003] Ionomer resins account for most of the cover stock resin in current use. A variety of improvements have been ma...

AI Technical Summary

Benefits of technology

[0006] Therefore, one object of the invention is to provide golf ball materials which have good thermal stability, flow and moldability, and which are capable of producing golf balls with outstanding rebound. Another object of the invention is to provide golf balls made using such golf ball materials.

[0007] Quite unexpectedly, it has been found that a mixture having good thermal stability, flow and moldability is obtained when 100 parts by weight of a base resin having (a) an olefin-unsaturated carboxylic acid binary random copolymer and / or a metal ion-neutralized olefin-unsaturated carboxylic acid binary random copolymer blended with (b) an olefin-unsaturated carboxylic acid-unsaturated carboxylate ternary random copolymer and / or a metal ion-neutralized olefin-unsaturated carboxylic acid-unsaturated carboxylate ternary random copolymer in a weight ratio of 0:100 to 30:70 is blended with (c) 5 to 80 parts by weight of a fatty acid and / or fatty acid derivative having a molecular weight of 280 to 1,500 and (d) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing acidic groups left unneutralized in the base resin and component (c). The mixture is suitable for molding and a molded part thereof exhibits improved rebound characteristics.

[0008] The molded part of the above-described golf ball material can form any desired constituent component of a golf ball (which is selected from among a one-piece golf ball, solid core, solid center, cover and other components). The golf ball thus constructed has very good rebound and improved initial velocity performance. The invention is predicated on these findings.

Problems solved by technology

These cover stocks, however, fall far short of practical levels.

During injection molding, the metallic soap in the cover stock decomposes and vaporizes to generate a large amount of fatty acid gas, often causing molding defects.

In addition, gas constituents settle on the surface of the molded part to considerably lower the paintability thereof.

Indeed, depending on the type of metallic soap used, the moldability and rebound of cover stock may in fact be severely compromised.

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