Methods for treating golf balls having a thermoplastic polyurethane cover

A coated golf ball formed by a method, the method comprising the steps of:

• providing a golf ball comprising at least one core layer and an outer cover layer, wherein the outer cover layer is formed from a thermoplastic polyurethane composition;
• applying a first mixture comprising a multi-functional isocyanate and solvent to the outer cover layer;
• applying a second mixture comprising:
• i) at least one compound selected from the group consisting of multi-functional amines and imines, and isocyanates;
• and ii) solvent, to the outer cover layer;
• applying a first polyurethane coating comprising unreacted isocyanate groups and having an isocyanate index of at least about 115 to the outer cover layer;
• treating the golf ball with heat;
• and
• applying a second polyurethane coating to the outer cover of the golf ball to form a coated golf ball.