Golf balls having two or more core layers formed from HNP compositions
View Patent ↗The present invention is directed to golf balls having a layer formed from a relatively soft HNP composition and a layer formed from a relatively hard HNP composition. Golf balls of the present invention have at least three layers, including an inner core layer, an outer core layer, a cover, and optionally an intermediate core layer. The present invention is not limited by which golf ball layers are formed from an HNP composition, so long as at least one layer is formed from a relatively soft HNP composition and at least one layer is formed from a relatively hard HNP composition. Relatively soft HNP compositions of the present invention comprise a highly neutralized acid copolymer preferably having a modulus of from 1,000 psi to 50,000 psi. Relatively hard HNP compositions of the present invention comprise a highly neutralized acid copolymer preferably having a modulus of from 25,000 psi to 150,000 psi.
1. A golf ball comprising:
(a) an inner core layer formed from a diene rubber composition;
(b) an outer core layer formed from a first HNP composition, the first HNP composition having a Shore D hardness of 45 or greater and comprising a highly neutralized ethylene/(meth)acrylic acid copolymer;
(c) an intermediate core layer disposed between the inner core layer and the outer core layer and formed from a second HNP composition, the second HNP composition having a Shore D hardness of 55 or less and comprising a highly neutralized ethylene/(meth)acrylic acid/alkyl (meth)acrylate copolymer; and
(d) a cover;
wherein the Shore D hardness of the first HNP composition is greater than the Shore D hardness of the second HNP composition.
2. The golf ball of claim 1 , wherein the Shore D hardness of the first HNP composition is from 50 to 80.
3. The golf ball of claim 1 , wherein the Shore D hardness of the first HNP composition is from 55 to 75.
4. The golf ball of claim 1 , wherein the Shore D hardness of the second HNP composition is from 10 to 55.
5. The golf ball of claim 1 , wherein the Shore D hardness of the second HNP composition is from 20 to 50.
6. The golf ball of claim 1 , wherein the Shore D hardness of the second HNP composition is from 30 to 48.
7. The golf ball of claim 1 , wherein the Shore D hardness of the first HNP composition is at least 3 greater than the Shore D hardness of the second HNP composition.
8. The golf ball of claim 1 , wherein the first HNP composition has a modulus of from 25,000 psi to 150,000 psi.
9. The golf ball of claim 1 , wherein the second HNP composition has a modulus of from 1,000 psi to 50,000 psi.
10. The golf ball of claim 1 , wherein the first HNP composition has a modulus of from 25,000 psi to 150,000 psi, the second HNP composition has a modulus of from 1,000 psi to 50,000 psi, and the modulus of the second HNP composition is at least 10% less than the modulus of the first HNP composition.
11. The golf ball of claim 10 , wherein the modulus of the second HNP composition is at least 25% less than the modulus of the first HNP composition.