Patent ID: 7255819

Claim:
A method of manufacturing a game ball, in which the game ball is molded in one shot by injection press foaming of a compounded material comprising EVA alone or blends thereof, the method comprising the steps of: providing a mold for use in injection press foaming, which has a size of 0.85-0.75 times the size of the game ball, compounding EVA alone or blends thereof as base polymer with an azodicarbonamide, sulfonyl hydrazide- or urea-based foaming agent, a peroxide-type crosslinking agent, a dispersant of stearic acid or wax, and an inorganic filler selected from the group consisting of CaCO 3 , MgCO 3 and mica, so as to be uniformly dispersed; mounting the mold on an injection press; transferring the compounded material into an injector cylinder of the injection press; performing injection molding of the compounded material on the injection press at an injector temperature of about 80-100° C., a press plate temperature of about 150-190° C. and a curing time of about 400-2000 seconds; and cooling the injection-molded material for about 10-30 minutes at about 40° C., thereby manufacturing a game ball.