Thermoplastic core having a negative hardness gradient formed from a plasticizer-based gradient-initiating solution
AssigneeAcushnet Company
InventorsMichael J. Sullivan, David A. Bulpett, Brian Comeau
Life of this patent
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Abstract
A golf ball comprising a thermoplastic core, the core having an outer diameter of 1.51 inches to 1.59 inches and having an outer surface and a geometric center, each having a hardness; an outer cover layer; and an inner cover layer disposed between the core and the outer cover layer; wherein the thermoplastic core has been exposed to a gradient-initiating solution comprising sufficient amount of plasticizer such that the hardness of the outer surface is less than the hardness of the geometric center to define a “negative” hardness gradient of 5 Shore C or greater.
Claims19
A golf ball comprising:
- a core consisting essentially of a thermoplastic material, the core having an outer diameter of 1.51 inches to 1.59 inches and having an outer surface and a geometric center, each having a hardness;
- an outer cover layer;
- and
- an inner cover layer disposed between the core and the outer cover layer;
- wherein the thermoplastic core has been exposed to a gradient-initiating solution comprising sufficient amount of plasticizer such that the hardness of the outer surface is less than the hardness of the geometric center to define a negative hardness gradient of 5 Shore C or greater;
- and
- wherein the thermoplastic material comprises an ionomer, a highly-neutralized ionomer, a thermoplastic polyurethane, a thermoplastic polyurea, a styrene block copolymer, a polyester amide, polyester ether, a polyethylene acrylic acid copolymer or terpolymer, or a polyethylene methacrylic acid copolymer or terpolymer.
A method of forming a golf ball comprising the steps of:
- providing a thermoplastic material comprising an ionomer, a highly-neutralized ionomer, a thermoplastic polyurethane, a thermoplastic polyurea, a styrene block copolymer, a polyester amide, polyester ether, a polyethylene acrylic acid copolymer or terpolymer, or a polyethylene methacrylic acid copolymer or terpolymer;
- forming the thermoplastic material into a core having a surface, a geometric center, and an outer diameter of 1.51 inches to 1.59 inches;
- combining a plasticizer and a solvent to form a gradient-initiating solution;
- soaking the thermoplastic core in the solution for a time of 5 minutes to 60 minutes to create a negative hardness gradient of at least 5 Shore C between the surface and the geometric center;
- forming an inner cover layer about the thermoplastic core, the inner cover layer comprising an ionomer;
- and
- forming an outer cover layer about the inner cover layer, the outer cover layer comprising a polyurea or a polyurethane.
Dependencies are inferred from the claim text.