A golf ball with reduced driver spin rate is provided. The golf ball comprises a core, an intermediate layer, and a cover. The intermediate layer is formed from a composition having a flexural modulus of at least about 70,000 psi and a melt flow rate of at least about 4 g/10-min. The composition comprises at least one high-acid ionomer. The intermediate layer further has a thickness of less than about 0.025 inches.
1. A golf ball, comprising:
a core;
a cover; and
an intermediate layer having a thickness of less than about 0.025 inches, disposed between the core and the cover, formed from a composition comprising a high-acid ionomer comprising at least about 16% by weight of a carboxylic acid;
wherein the composition has a flexural modulus of at least 80,000 psi and a melt flow rate of about 10 g/10-min to about 100 g/10-min.
2. The golf ball of claim 1 , wherein the high-acid ionomer has a melt flow rate of at least about 4 g/10-min, and wherein the carboxylic acid is neutralized by at least about 10% with a metal cation.
3. The golf ball of claim 1 , wherein the composition has a material hardness of at least about 65 Shore D.
4. The golf ball of claim 3 , wherein the material hardness is at least about 70 Shore D.
5. The golf ball of claim 1 , wherein the intermediate layer has an on-ball hardness of less than about 70 Shore D.
6. The golf ball of claim 5 , wherein the on-ball hardness is less than about 65 Shore D.
7. The golf ball of claim 1 , wherein the thickness of the intermediate layer is from about 0.015 inches.
8. The golf ball of claim 1 , wherein the composition further comprises a modulus-enhancing filler such that the flexural modulus of the composition with the filler is substantially greater than without the filler.
9. The golf ball of claim 8 , wherein the modulus-enhancing filler comprises fibers, filaments, flakes, whiskers, wires, tubes, or particulates of nano-scale or micro-scale.
10. The golf ball of claim 1 , wherein the core has a diameter of at least about 1.55 inches.
11. A golf ball, comprising:
a core;
a cover; and
an intermediate layer having a thickness of from about 0.005 inches to about 0.02 inches, disposed between the core and the cover, formed from a composition comprising a blend of a first and a second high-acid ionomers each having a carboxylic acid content of at least about 16% by weight and a melt flow rate of at least about 4 g/10-min;
wherein the composition has a flexural modulus of at least about 85,000 psi and a melt flow rate of about 10 g/10-min to about 100 g/10-min.
12. The golf ball of claim 11 , wherein the first and second high-acid ionomers are neutralized by about 30% to about 100% and have a weight ratio of from about 5:95 to about 95:5.
13. The golf ball of claim 11 , wherein the composition has a material hardness of at least about 65 Shore D, and wherein the intermediate layer has an on-ball hardness of no greater than about 70 Shore D.
14. The golf ball of claim 13 , wherein the material hardness is at least about 70 Shore D, and the on-ball hardness is no greater than about 65 Shore D.
15. The golf ball of claim 11 , wherein the composition further comprises a modulus-enhancing filler such that the flexural modulus of the composition with the filler is substantially greater than without the filler.
16. A golf ball, comprising:
a core;
a cover; and an intermediate layer having a thickness of from about 0.005 inches to about 0.02 inches disposed between the core and the cover, formed from a composition comprising at least one high-acid ionomer comprising at least about 16% by weight of a carboxylic acid, wherein the composition has a flexural modulus of at least 80,000 psi and a melt flow rate of about 10 g/10-min to about 100 g/10-min.
17. The golf ball of claim 16 , wherein the composition further comprises at least a second high-acid ionomer comprising at least about 16% by weight of a carboxylic acid and having a melt flow rate of at least about 4 g/10-min.
18. The golf ball of claim 16 , wherein the composition further comprises at least one material chosen from ionomers having a melt flow rate of less than about 4 g/10-min and non-ionomeric materials.
19. The golf ball of claim 18 , wherein the non-ionomeric material comprises at least one material chosen from thermoplastic elastomers, non-ionomeric olefin/acid copolymers or terpolymers, polyamides, polyolefins, polyurethanes, polyureas, epoxies, polyesters, polyetheresters, polyetheramides, polyamides, metallocene-catalyzed polymers, functionalized styrene-butadiene elastomers, -styrenic block copolymers, acrylonitrile-butadiene-styrene copolymers, and silicone.
20. The golf ball of claim 18 , wherein the non-ionomeric material has a carboxylic acid content of about 5% to about 30% by weight.