Golf balls having layers made of silicone elastomers
Multi-layered golf balls having at least one layer made of a foamed silicone composition are provided. Multi-layered golf balls having at least one layer made of non-foamed silicone elastomer composition also are provided. For example, three-piece, four-piece, and five-piece golf balls containing different core and cover structures can be made. The foamed silicones have good thermal stability and durability without sacrificing resiliency. The non-foamed silicone elastomers have high elongation, tensile strength, chemical/fluid-resistance, and weatherability properties. These compositions can be used to form any layer, for example, core, intermediate, or cover, in the golf ball.
1. A golf ball, comprising:
i) a core having at least one layer, the layer comprising a blend of thermoset rubber and thermoplastic non-foamed silicon elastomer;
ii) an inner cover layer comprising a thermoplastic composition, the composition comprising a blend of thermoplastic non-foamed silicone elastomer and thermoplastic polyurethane, the inner cover layer being disposed about the core and having a midpoint hardness in the range of about 15 to about 60 Shore A; and
iii) an outer cover layer disposed about the inner cover layer and having an outer surface hardness in the range of about 55 to about 75 Shore D, wherein the outer surface hardness of the outer cover layer is greater than the midpoint hardness of the inner cover layer.
2. The golf ball of claim 1 , wherein the inner cover layer has a midpoint hardness in the range of about 15 to about 54 Shore A and the outer cover layer has an outer surface hardness in the range of about 58 to about 71 Shore D, wherein the outer surface hardness of the outer cover layer is greater than the midpoint hardness of the inner cover layer.
3. The golf ball of claim 1 , wherein the inner cover layer has a thickness in the range of about 0.010 to about 0.075 inches.
4. The golf ball of claim 1 , wherein the silicone elastomer composition is made from at least one heterobifunctional macromer, and the composition has an elongation greater than 2000%.
5. The golf ball of claim 1 , wherein the silicone elastomer composition is made from at least one heterobifunctional macromer, and the composition has an elongation greater than 3000%.
6. The golf ball of claim 1 , wherein the outer cover layer comprises a polymer selected from the group consisting of: ethylene add copolymer ionomers; polyesters; polyamides; polyurethanes, polyureas; fluoropolymers; polystyrenes; polypropylenes, polyethylenes; polyvinyl chlorides; polyvinyl acetates; polycarbonates; polyvinyl alcohols; polyethers; polyimides, polyetherketones, polyamideimides; and mixtures thereof.
7. The golf ball of claim 1 , wherein the outer cover comprises an ethylene acid copolymer containing acid groups such that less than 70% of the acid groups are neutralized.
8. The golf ball of claim 1 , wherein the outer cover comprises an ethylene acid copolymer containing acid groups such that greater than 70% of the acid groups are neutralized.
9. The golf ball of claim 1 , wherein the outer cover comprises a polymer selected from the group consisting of polyurethanes, polyueas, polyurethane-urea hybrids, and copolymers and blends thereof.