Golf ball with a non-ionomeric inner cover, stiff TPU intermediate cover, and cast thermoset outer cover
View Patent ↗A golf ball including a core and a cover disposed about the core. The cover includes a thermoplastic inner cover layer having a hardness between 55 and 60 Shore D; an outer cover layer having a hardness between 55 and 60 Shore D; and a stiff intermediate cover layer disposed between the inner and outer cover layers and having a hardness greater than the inner cover layer and the outer cover layer. The inner cover layer is formed from a non-ionomeric composition including a non-ionomeric stiffening polymer and at least one E/Y copolymer or E/X/Y terpolymer, where E is an olefin, Y is a carboxylic acid, and X is a softening comonomer. The intermediate cover layer is formed from a stiff thermoplastic polyurethane or polyurea composition and the cover outer cover layer is formed from a thermoset polyurethane, a polyurea, or a urethane-urea blend.
1. A golf ball comprising:
a core; and
a cover disposed adjacent the core, the cover comprising:
a non-ionomeric inner cover layer comprising an E/Y copolymer where E is an olefin and Y is a carboxylic acid, the inner cover being disposed about the core and having a hardness of 45 Shore D to 68 Shore D;
a castable thermoset polyurethane outer cover layer having a hardness between 40 Shore D and 62 Shore D; and
a stiff thermoplastic polyurethane or polyurea intermediate cover layer disposed between the inner and outer cover layers, the non-ionomeric intermediate cover layer having a hardness greater than the inner cover layer; and
the outer cover layer, the hardness being from 70 Shore D to 90 Shore D;
wherein the inner cover layer has a first thickness, the outer cover layer has a second thickness, and the intermediate cover layer has a third thickness less than the first or second thickness by at least 20%.
2. The golf ball of claim 1 , wherein the intermediate layer hardness is greater than the inner cover layer hardness and greater than the outer cover layer hardness by at least 5 Shore D.
3. The golf ball of claim 2 , wherein the intermediate layer hardness is greater than the inner cover layer hardness and greater than the outer cover layer hardness by at least 10 Shore D.
4. The golf ball of claim 1 , wherein the outer cover layer hardness is about 52 Shore D to about 60 Shore D.
5. The golf ball of claim 1 , wherein the inner cover layer hardness is about 50 Shore D to about 62 Shore D.
6. The golf ball of claim 5 , wherein the inner cover layer hardness is about 52 Shore D to about 60 Shore D.
7. The golf ball of claim 1 , wherein the core comprises a center and at least one outer core layer.
8. The golf ball of claim 1 , wherein the non-ionomeric inner cover layer further comprises a polyester/polycarbonate blend, a polyester resin, an acetal resin, a polyamide resin, a polyetheramide resin, a polyester resin, a polyester elastomer, a liquid crystalline polyester, a polyester/polyamide blend, a poly(arylene ether)/polyester resin, or a polyimide.
9. The golf ball of claim 1 , wherein the olefin is ethylene and the carboxylic acid is acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, or a combination thereof.
10. The golf ball of claim 1 , wherein a combination of the inner cover, the intermediate cover, and the outer cover have a total thickness of 0.125 inches or less.