Golf balls including a crosslinked thermoplastic polyurethane cover layer having improved scuff resistance

摘要

This disclosure relates to golf balls having a cover layer made from a crosslinked thermoplastic polyurethane elastomer. The crosslinked thermoplastic polyurethane elastomer includes crosslinks located in the hard segments, where the crosslinks being the reaction product of unsaturated bonds located in the hard segments catalyzed by a free radical initiator. The crosslinks may be formed from an unsaturated diol as a chain extender. The unsaturated diol may be trimethylolpropane monoallylether (TMPME). The cover layer may have certain properties, such as a desirable flexural modulus value and a desirable Shore D hardness value, that further contribute to the golf ball having a high degree of scuff resistance.

主权项

1. A method of making a golf ball comprising:
(a) preparing a thermoplastic polyurethane elastomer having crosslinks in hard segments by reacting (i) an unsaturated diol in which R1 is a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkyl-aryl group, substituted or unsubstituted ether group, substituted or unsubstituted ester group, a combination of these, or H, and optionally includes an unsaturated bond in any main chain or side chain of any group; R2 comprises an allyl group optionally attached by a substituted or unsubstituted alkylene group, substituted or unsubstituted arylene group, substituted or unsubstituted alkylarylene group, substituted or unsubstituted ether group, or substituted or unsubstituted ester group; and x and y are integers independently having a value from 1 to 10, (ii) a diisocyanate, (iii) a polyol having a molecular weight between about 500 and about 4000, and optionally (iv) a chain extender selected from diols, diamines, and amino alcohols having a molecular weight less than about 450; wherein a free radical initiator induces crosslinking of the allyl group and, if present, the optional unsaturated bond of R1 and wherein the NCO index of the reactants is from about 0.9 to about 1.3 to form a crosslinked, thermoplastic polyurethane elastomer; (b) forming the thermoplastic polyurethane into pellets or chips; (c) molding the pellets or chips to form a cover layer around a ball comprising an inner core layer, an outer core layer substantially surrounding the inner core layer, and an inner cover layer substantially surrounding the outer core layer to form a golf ball, wherein the inner core layer comprises a highly neutralized acid polymer composition that is neutralized to 70% or higher, the outer core layer comprises a polybutadiene rubber; and the inner cover layer comprises a thermoplastic polyurethane.