Play balls, pressureless tennis balls and rubber compounds for making them

摘要

A hollow rubber play ball is disclosed that uses a combination two or more fillers to produce desirable playing properties in a tennis ball as specified by the International Lawn Tennis Federation (ITF). The preferred play ball is a pressureless tennis ball. The specific fillers disclosed are mineral type particulate reinforcing fillers such as silicas and carbon black, polymeric fillers such as cellulose, a reaction product of grafting polyethylene with cellulose, and ethylene-vinyl acetate copolymers. These fillers can also have surface treatments to enhance the elastomer-filler interaction. Another reinforcing filler that can be introduced with the rubber components is the non-rubber constituents in skim rubber that serve to increase the modulus of a compounded rubber.