초록

A two-piece molded golf ball comprised of a resilient core (polybutadiene-basic zinc methacrylate covulcanizate) and an ionomer resin cover, the cover having a dimple design of icosahedral array. This ball has superior flight performance compared to conventional two-piece molded balls.

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A solid two-piece molded golf ball having a spherical core having a diameter of 1.505 inches, a PGA compression of 65, a rebound of at least 75% and a specific gravity of 1.20, the said core comprising a cross-linked composition containing 100 parts by weight of polybutadiene elastomer having a cis-

A solid two-piece molded golf ball having a spherical core having a diameter of 1.505 inches, a PGA compression of 65, a rebound of at least 75% and a specific gravity of 1.20, the said core comprising a cross-linked composition containing 100 parts by weight of polybutadiene elastomer having a cis-1,4-polybutadiene content of 50% by weight or more and from 10 to 60 parts by weight of preformed zinc oxide-methacrylic acid reaction product in which the zinc oxide and methacrylic acid are combined in the proportions required by basic zinc methacrylate, said preformed reaction product being finely ground to a fineness such that at least 99% passes a 325 mesh sieve, said core composition containing a free radical generating curing agent in amount sufficient to cure the composition, the said core being surrounded by a cover composition of sufficient thickness to provide a ball diameter of 1.680 inches, said cover composition comprising an ionomer resin which is a thermoplastic, resinous ionic copolymer of an olefin having from 2 to 8 carbon atoms and a metal salt of an unsaturated monocarboxylic acid containing from 2 to 8 carbon atoms, the outer surface of the said cover being painted and having a dimple pattern consisting of essentially 252 dimples circular in cross-section, the dimensions of the dimples expressed as mold dimensions being 0.160 inch in diameter by 0.0145 inch deep, said dimples being arranged in an icosohedral array uniformly distributed on the surface of the ball and covering approximately fifty percent of the area of the ball surface, the molded ball having been deflashed by centerless grinding, whereby the ball exhibits improved flight characteristics.