Patent ID: 6939250
Filing Date: 2005-09-06
Classification: A63B,C08L

Abstract:
1. A multi-piece golf ball comprising: a core having a diameter of 30 to 40 mm, said core being made from a rubber composition mainly containing polybutadiene; at least one intermediate layer including an outermost layer having a thickness of 0.5 to 2.0 mm, said outermost layer being made from a non-ionomer based thermoplastic resin; and a cover having a thickness of 1.0 to 3.0 mm, said cover being made from material obtained by dispersedly blending at least one kind of silicone powder selected from a silicone rubber powder, a silicone resin powder, and a composite powder thereof, in a main resin component containing an ionomer resin in an amount of 50% by weight or more; wherein said core has a hardness corresponding to a deflection in a range of 3.5 to 6.5 mm under an applied load of 100 kg; said outermost layer of said at least one intermediate layer has a Durometer D hardness in a range of 20 to 55, and said cover is harder than said outermost layer of said at least one intermediate layer and has a Durometer D hardness in a range of 50 to 70; and dimples of the number of 300 to 550 pieces are formed in the surface of said golf ball in such a manner that a dimple total volume ratio VR, which is a ratio of the total of volumes of dimple spaces under the planes surrounded by edges of the dimples in the surface of said golf ball to the total volume of a virtual ball as a result of assumption that no dimple is formed in the surface of said golf ball, is in a range of 0.85% or less; wherein the composite powder comprises silicone rubber particles surface coated with a silicone resin.