Golf ball composition

Abstract

The present invention relates to golf ball having a core and an outer cover layer made from a blend composition of about 1 to about 99 wt % of a block copolymer having no polar functionality; and from about 1 to about 99 wt % (based on the combined weight of Components A and B) of either one or more unimodal acidic polymers; or a bimodal polymer blend composition including a high molecular weight component having a weight average molecular weight, Mw, of about 80,000 to about 500,000 and including one or more ethylene / α,β-ethylenically unsaturated C3-8 carboxylic acid copolymers and / or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; and a low molecular weight component having a weight average molecular weight, Mw, of about from about 2,000 to about 30,000 and comprising one or more ethylene / α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and / or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers. Also included in the blend is one or more basic metal salts present in an amount to neutralize at greater than or equal to about 30 percent of the acid groups of the acid polymer. The blend composition has a melt index of greater than about 5 g / 10 min, a flexural modulus of from about 500 to about 100,000 psi, a material Shore D hardness of from about 25 to about 70; and the golf ball has a cover layer Shire D hardness as measured on the ball of from about 35 to about 70 and a shear cut resistance of less than about 4.

Description

[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 140,516 filed Dec. 23, 2008, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]The present invention relates to sports equipment in general, and more particularly to golf balls comprising a particular composition suitable for use in golf ball manufacture. In one embodiment, the present invention is used in the manufacture of a golf ball comprising a core, a cover layer and, optionally, one or more inner cover layers. In one preferred embodiment, a golf ball is disclosed in which the cover layer comprises the novel composition of the present invention. In another preferred embodiment, a golf ball is disclosed in which at least one intermediate layer comprises the novel composition of the present invention.DESCRIPTION OF RELATED ART[0003]The application of synthetic polymer chemistry to the field of sports equipment has revolutionized the performance of athletes in...

AI Technical Summary

Benefits of technology

[0014]In one aspect the present invention is a two piece golf ball having a core and an outer cover layer; made from a blend composition of about 1 to about 99 wt % of a block copolymer having no polar functionality; and from about 1 to about 99 wt % (based on the combined weight of Components A and B) of either one or more unimodal acidic polymers; or a bimodal polymer blend composition including a high molecular weight component having a weight average molecular weight, Mw, of about 80,000 to about 500,000 and including one or more ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and/or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; and a low molecular weight component having a weight average molecul

Problems solved by technology

One-piece balls are inexpensive and very durable, but do not provide great distance because of relatively high spin and low velocity.

However balata-covered balls, although exhibiting high spin and soft feel, were often deficient in terms of the velocity of the ball when it leaves the club face which in turn affects the distance the ball travels.

However, the incorporation of more acid in the ionomer and / or increasing its degree of neutralization results in a material with increased polarity, and hence one which is often less compatible with other potential blend materials.

Also increasing the acid content of the ionomer while increasing C.O.R. may render the ball too hard and brittle causing a loss of shot feel, control (i.e., the ability to spin the ball) and may render the cover too brittle and prone to premature failure.

Finally, the incorporation of more acid in the ionomer and / or increasing its degree of neutralization typically results in an increase in melt viscosity which in turn greatly decreases the processability of these resins.

Attempts to mediate these effects by adding softer terpolymeric ionomers to high acid ionomer compositions to adjust the hardness and improve the shot “feel” often result in concomitant loss of C.O.R. and hence distance.

However, it has been observed that covers incorporating these triblock copolymers can suffer from cracks after being hit during play.

This cracking leads to substantial deterioration in ball performance and long-term durability.

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