Tennis ball having a thermoplastic core

A finished tennis ball comprising:

• a non-foamed thermoplastic core defining an internal volume, the core having an outer meltable surface and comprising:
• 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, a thickness of the thermoplastic material of between 3.0 and 8.0 mm, the thickness of the thermoplastic material configured to maintain dimensional stability at internal pressures of between zero and 15 psi;
• and
• a felt cover at least partially covering the core,
• wherein the finished tennis ball conforms to ITF and USTA size, weight, deformation and rebound requirements,
• wherein the non-foamed thermoplastic core comprises one or more ethylene-alkene copolymers.