GOLF BALLS HAVING A FOAM CENTER
Large diameter golf balls having a foam core are provided.
1 . A golf ball having a diameter of 1.70 inches or greater and comprising:
an inner core layer having a diameter of 1.60 inches or greater and formed from a foamed polyurethane composition, the inner core layer having an outer surface hardness (H inner core surface ) and a center hardness (H inner core center ), the H inner core surface being the same or less than the H inner core center to provide a zero or negative hardness gradient; and
a cover layer formed from a composition comprising:
an acid copolymer of ethylene and an α,β-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;
an organic acid or salt thereof;
a cation source present in an amount sufficient to neutralize greater than 80% of all acid groups present in the composition; and
optionally a non-acid polymer selected from the group consisting of polyolefins, polyamides, polyesters, polyethers, polyurethanes, metallocene-catalyzed polymers, single-site catalyst polymerized polymers, ethylene propylene rubber, ethylene propylene diene rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers, and functionalized derivatives thereof.
2 . The golf ball of claim 1 , wherein the golf ball has a diameter of 1.80 inches or greater.
3 . The golf ball of claim 1 , wherein the golf ball has a diameter of 2.00 inches or greater.
4 . A golf ball having a diameter of greater than 1.70 inches and comprising:
an inner core layer having a diameter of 1.30 inches or greater and formed from a foamed polyurethane composition, the inner core layer having an outer surface hardness (H inner core surface ) and a center hardness (H inner core center ), the H inner core surface being greater than the H inner core center to provide a positive hardness gradient; and
an outer core layer having a thickness of 0.20 inches or greater and formed from a thermoset composition, the outer core layer having an outer surface hardness (H outer surface of OC ) and an inner surface hardness (H inner surface of OC ), the H outer surface of OC being the same or less than the H inner surface of OC to provide a zero or negative hardness gradient; and
a cover layer.
5 . The golf ball of claim 4 , wherein the golf ball has a diameter of 1.80 inches or greater.
6 . A golf ball having a diameter of greater than 1.70 inches and comprising:
an inner core layer having a diameter of 1.30 inches or greater and formed from a foamed polyurethane composition, the inner core layer having an outer surface hardness (H inner core surface ) and a center hardness (H inner core center ), the H inner core surface being the same or less than the H inner core center to provide a zero or negative hardness gradient; and
an outer core layer having a thickness of 0.20 inches or greater and formed from a thermoset composition, the outer core layer having an outer surface hardness (H outer surface of OC ) and an inner surface hardness (H inner surface of OC ), the H outer surface of OC being greater than the H inner surface of OC to provide a positive hardness gradient; and
a cover layer.
7 . The golf ball of claim 6 , wherein the golf ball has a diameter of 1.80 inches or greater.
8 . A golf ball having a diameter of greater than 1.70 inches and comprising:
an inner core layer having a diameter of 1.30 inches or greater and formed from a foamed polyurethane composition, the inner core layer having an outer surface hardness (H inner core surface ) and a center hardness (H inner core center ), the H inner core surface being the same or less than the H inner core center to provide a zero or negative hardness gradient; and
an outer core layer having a thickness of 0.20 inches or greater and formed from a thermoset composition, the outer core layer having an outer surface hardness (H outer surface of OC ) and an inner surface hardness (H inner surface of OC ), the H outer surface of OC being the same or less than the H inner surface of OC to provide a zero or negative hardness gradient; and
a cover layer.
9 . The golf ball of claim 8 , wherein the golf ball has a diameter of 1.80 inches or greater.