| 摘要 |
A core, for a pressureless or low pressure tennis ball having an internal pressure of up to 7 psi above atmospheric pressure, was made of from a rubber composition wherein up to 60 % by weight of the total polymer content comprises either a copolymer of ethylene and propylene of a terpolymer of ethylene, propylene and up to 12 % by weight of a non-conjugated diene monomer. The most suitable elastomers are those contg. 70 mole % or more of ethylene. The non-conjugated diene may be 1,4-hexadiene, ethylidene norbornene or di-cyclo-pentadiene.. |
