Golf ball having dual core and thin polyurethane cover formed by RIM
View Patent ↗The present invention is directed to a golf ball comprising a dual core component, an inner cover layer and an outer cover layer. The dual core comprises an interior spherical center component formed from a thermoset material, a thermoplastic material, or combinations thereof. The dual core also comprises a core layer disposed about the center component, formed from a thermoset material, a thermoplastic material, or combinations thereof. The one or more polyurethane layers are preferably formed via a reaction injection molding (RIM) technique. The inner cover layer is relatively soft and preferably comprises an ionomer or ionomer blend. The outer cover layer is relatively hard and comprises a hard polyurethane. The resulting multi-layered golf ball of the present invention provides for enhanced distance without sacrificing playability or durability when compared to known multi-layer golf balls.
1. A method for forming a golf ball comprising:
providing a core center component;
forming a core layer about said core center component;
forming an inner cover layer on said core layer, such that said inner cover layer has a thickness ranging from about 0.0075 inches to about 0.0225 inches, wherein said inner cover layer has a Shore D hardness of less than 45; and
molding an outer cover layer comprising a polyurethane material about said inner cover layer by use of a reaction injection molding technique.
2. The method of claim 1 wherein said inner cover layer has a thickness of from about 0.0125 to 0.0175 inches.
3. The method of claim 1 wherein said outer cover layer has a thickness of from about 0.0075 to 0.0225 inches.
4. The method of claim 1 wherein said golf ball has a PGA compression of less than 115.
5. The method of claim 1 wherein said total thickness of said outer cover layer and said inner cover layer ranges from about 0.015 inches to about 0.045 inches.
6. The method of claim 1 wherein said outer cover layer has a Shore D hardness of at least 50.
7. A method of forming a golf ball having a dual core and a multi-layer cover assembly wherein at least one layer of the multi-layer cover assembly is a polyurethane with a polyurethane cover layer via a reaction injection molding process, the method comprising the steps of:
providing a first material suitable for forming a core center component;
forming a core center from the first material;
providing a second material different in composition than the first material, the second material being suitable for forming a core layer;
forming a core layer about the core center component from the second material, thereby producing a dual core;
providing a third material suitable for forming an inner cover layer;
forming an inner cover layer about the dual core from the third material;
providing a fourth material different in composition than the third material, the fourth material being suitable for forming an outer cover layer; and
forming an outer cover layer on the inner cover layer from the fourth material, thereby producing a multi-layer cover assembly;
wherein the fourth material comprises a polyurethane material, and wherein steps of forming the inner cover layer and forming the outer cover layer are performed such that the thickness of the multi-layer cover is from about 0.015 inches to about 0.045 inches,
wherein the the step of forming an outer cover layer is performed by: providing a molding device having a cavity adapted to retain a golf ball core;
providing an isocyanate component;
providing a polyol component;
positioning the inner covered dual core within the cavity of the molding device;
introducing the isocyanate component and the polyol component into the cavity of the molding device; whereby the isocyanate component and the polyol component react within the cavity to form the polyurethane; and
molding the outer cover layer about the inner covered dual core, and
wherein the Shore D hardness of the cover is less than 50, and the Shore D hardness of the outer cover layer is at least 50.
8. The method of claim 7 wherein said inner cover layer has a thickness of from about 0.0125 inches to about 0.0175 inches.
9. The method of claim 7 wherein said outer cover layer has a thickness ranging from about 0.0125 inches to about 0.0175 inches.
10. The method of claim 7 wherein said golf ball exhibits a PGA compression of less than 115.
11. The method of claim 7 wherein the core center component comprises a thermoplastic material.
12. The method of claim 7 wherein the core assembly exhibits a coefficient of restitution of at least 0.750.
13. The method of claim 7 wherein the core assembly exhibits a PGA compression of less than 100.
14. The method of claim 7 wherein the core assembly has a weight of 25 to 40 grams.
15. The method claim 7 wherein the thickness of the multi-layer cover assembly ranges from about 0.025 to about 0.035 inches.
16. The method claim 7 wherein the isocyanate is selected from the group consisting of diphenylmethane diisocyanate and toluene diisocyanate.