Golf balls having a low modulus HNP layer and a high modulus HNP layer
View Patent ↗The present invention is directed to golf balls consisting of a dual-layer core and a cover. The core consists of an inner core layer formed from a high modulus HNP composition and an outer core layer formed from a low modulus HNP composition. The outer core layer has an outer surface hardness less than the outer surface hardness of the inner core layer.
1. A golf ball consisting of a core and a cover, wherein the core has an overall diameter of from 1.400 inches to 1.660 inches and consists of:
an inner core layer having a diameter of from 0.125 inches to 0.750 inches, an outer surface hardness of 70 Shore C or greater, 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; and
an outer core layer having an outer surface hardness less than the outer surface hardness of the inner core layer and 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;
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 outer core layer has a specific gravity greater than or equal to the inner core layer specific gravity.
3. The golf ball of claim 1 , wherein the core has an overall diameter of from 1.510 inches to 1.600 inches.
4. The golf ball of claim 1 , wherein the inner core layer has a diameter of from 0.250 inches to 0.375 inches.
5. The golf ball of claim 1 , wherein the inner core layer has an outer surface hardness of 85 Shore C or greater.
6. The golf ball of claim 1 , wherein the outer core layer has an outer surface hardness of 80 Shore C or less.
7. The golf ball of claim 1 , wherein the cover consists of a single layer having an outer surface hardness of 60 Shore D or less and a thickness of from 0.015 inches to 0.100 inches.
8. The golf ball of claim 1 , wherein the cover consists of:
an inner cover layer having an outer surface hardness of 65 Shore D or greater and a thickness of from 0.020 inches to 0.080 inches; and
an outer cover layer having an outer surface hardness of 60 Shore D or less and a thickness of from 0.015 inches to 0.055 inches.
9. The golf ball of claim 1 , wherein the cover consists of:
an inner cover layer formed from a partially or fully neutralized polymer composition and having an outer surface hardness of 65 Shore D or greater and a thickness of from 0.015 inches to 0.035 inches; and
an outer cover layer formed from a polyurethane or polyurea composition and having a material hardness of 50 Shore D or less and a thickness of from 0.015 inches to 0.035 inches.
10. A golf ball consisting of:
a core having an overall diameter of from 1.400 inches to 1.620 inches and consisting of:
an inner core layer having a diameter of from 0.250 inches to 0.500 inches, an outer surface hardness of 81 Shore C or greater, 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; and
an outer core layer having an outer surface hardness of 90 Shore C or less and 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; and
a cover consisting of:
an inner cover layer having an outer surface hardness of 65 Shore D or greater and a thickness of from 0.020 inches to 0.080 inches; and
an outer cover layer having a surface hardness of 60 Shore D or less and a thickness of from 0.015 inches to 0.055 inches;
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.
11. The golf ball of claim 10 , wherein the outer core layer has a specific gravity greater than or equal to the inner core layer specific gravity.
12. The golf ball of claim 10 , wherein the core has an overall diameter of from 1.510 inches to 1.600 inches.
13. The golf ball of claim 10 , wherein the inner core layer has a diameter of from 0.250 inches to 0.375 inches.
14. The golf ball of claim 10 , wherein the inner core layer has an outer surface hardness of 85 Shore C or greater.
15. The golf ball of claim 14 , wherein the outer core layer has an outer surface hardness of 80 Shore C or less.
16. The golf ball of claim 10 , wherein the outer surface hardness of the outer core layer is less than the outer surface hardness of the inner core layer.