Patent ID: 7037216
Filing Date: 2006-05-02
Classification: A63B

Abstract:
1. A multi-piece golf ball composed of a core and an outermost cover layer, with one or more inner cover layers interposed between them, which is characterized in that said core is made mainly of a polybutadiene which is synthesized with using a catalyst of rare earth element such that the content of cis-1,4 bond is no less than 60%, said core has a diameter of 34.7 to 40.7 mm, said core undergoes deflection amounting to 3.0 to 5.0 mm under a load of 100 kg, said outermost cover layer is made mainly of a resin compound which is a mixture of component (a) which is selected from olefin-unsaturated carboxylic acid copolymer, olefin-unsaturated carboxylic acid-unsaturated carboxylic ester copolymer, and their salt neutralized with metal ions, and component (b) which is a binary copolymer composed of a polyolefin component (b-1) and a polyamide component (b-2), said outermost cover layer has a Shore D hardness of 55 to 70 and a thickness of 0.5 to 2.0 mm, and said inner cover layer has a Shore D hardness of 15 to 55 and a thickness of 0.5 to 2.0 mm.