US Patent 11247103 Tennis ball having a thermoplastic core

A method for forming a tennis ball including the steps of providing a non-foamed thermoplastic core and providing a non-smooth textured surface on the core. The thermoplastic core including a thermoplastic material having a specific gravity of 0.86 to 1.38, a flexural modulus of 2.0 to 50.0 MPa, and a Shore D hardness of 10 to 70. The thermoplastic material having a thickness between 3.0 and 8.0 mm. The thickness of the thermoplastic material being configured to maintain dimensional stability at internal pressures of between zero and 15 psi.