Golf balls having two or more core layers formed from HNP compositions
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 relatively hard HNP composition and an outer core layer formed from a relatively soft 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 comprising a core and a cover, wherein the core has an overall diameter of from 1.400 inches to 1.660 inches and comprises:
an inner core layer having a diameter of from 0.125 inches to 1.000 inches, an outer surface hardness of from 80 Shore C to 95 Shore C, and formed from a first HNP composition, the first HNP composition having a material hardness of 45 Shore D or greater and comprising a highly neutralized ethylene/(meth)acrylic acid copolymer;
an intermediate core layer formed from a rubber composition and having a thickness of from 0.050 inches to 0.400 inches; 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 second HNP composition, the second HNP composition having a material hardness of 55 Shore D or less and comprising a highly neutralized ethylene/(meth)acrylic acid/alkyl (meth)acrylate copolymer.
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 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.
6. 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.
7. 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.