Golf balls having a low modulus HNP layer and a high modulus HNP layer
View Patent ↗The present invention is directed to golf balls comprising a dual-layer core and a cover. The core comprises a center formed from a high modulus HNP composition, and an outer core layer formed from a low modulus HNP composition. Low modulus HNP compositions of the present invention have a modulus of from 1,000 psi to 50,000 psi. High modulus HNP compositions of the present invention have a modulus of from 25,000 psi to 150,000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition. The cover comprises an inner cover layer formed from a thermoplastic composition and an outer cover layer formed from a polyurethane or polyurea composition.
1. A golf ball consisting essentially of:
(a) a center having a diameter of from 1.20 inches to 1.30 inches and formed from a high modulus HNP composition, the high modulus HNP composition comprising:
a highly neutralized ethylene/(meth)acrylic acid copolymer having a modulus of from 25,000 psi to 150,000 psi;
(b) an outer core layer formed from a low modulus HNP composition, the low modulus HNP composition comprising:
a highly neutralized ethylene/(meth)acrylic acid/alkyl(meth)acrylate copolymer having a modulus of from 1,000 psi to 50,000 psi;
(c) an inner cover layer formed from a thermoplastic composition; and
(d) an outer cover layer formed from a polyurethane or polyurea composition;
wherein the modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.
2. The golf ball of claim 1 , wherein the center has a center hardness of 55 Shore C or greater.
3. The golf ball of claim 1 , wherein the outer core layer has a surface hardness of 75 Shore C or greater.
4. The golf ball of claim 3 , wherein the center has a surface hardness of 70 Shore C or greater.
5. The golf ball of claim 1 , wherein the inner cover layer has a material hardness less than the surface hardness of the outer core layer.
6. The golf ball of claim 1 , wherein the core has an overall dual core compression of from 75 to 90.
7. The golf ball of claim 1 , wherein the core has an overall dual core diameter of from 1.52 inches to 1.59 inches.
8. A golf ball consisting essentially of:
(a) a center having a diameter of from 0.75 inches to 1.19 inches, and formed from a high modulus HNP composition, the high modulus HNP composition comprising:
a highly neutralized ethylene/(meth)acrylic acid copolymer having a modulus of from 25,000 psi to 150,000 psi;
(b) an outer core layer formed from a low modulus HNP composition, the low modulus HNP composition comprising:
a highly neutralized ethylene/(meth)acrylic acid/alkyl(meth)acrylate copolymer having a modulus of from 1,000 psi to 50,000 psi;
(c) an inner cover layer formed from a thermoplastic composition; and
(d) an outer cover layer formed from a polyurethane or polyurea composition;
wherein the modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.
9. The golf ball of claim 8 , wherein the center has a center hardness of 55 Shore C or greater.
10. The golf ball of claim 8 , wherein the outer core layer has a surface hardness of 75 Shore C or greater.
11. The golf ball of claim 10 , wherein the center has a surface hardness of 70 Shore C or greater.
12. The golf ball of claim 8 , wherein the inner cover layer has a material hardness less than the surface hardness of the outer core layer.
13. The golf ball of claim 8 , wherein the core has an overall dual core compression of from 75 to 90.
14. The golf ball of claim 8 , wherein the diameter of the center is from 0.850 inches to 1.150 inches.
15. The golf ball of claim 8 , wherein the diameter of the center is from 0.875 inches to 1.125 inches.
16. The golf ball of claim 8 , wherein the core has an overall dual core diameter of from 1.52 inches to 1.59 inches.