Golf ball and method of making same
Golf ball comprising a core, an outer layer and at least one adhesion promoting coating disposed between each of the core and the outer layer; the core comprising a rubber composition comprising at least one zinc-containing and/or magnesium-containing component; the outer layer comprising at least one ionomer; and the adhesion promoting coating comprising a waterborne dispersion comprised of at least one ethylene acid copolymer having an acid content of at least 15% by weight wherein the copolymer is at least partially neutralized with one or more neutralizing agent; wherein at least one neutralizing agent is selected from ammonia compounds and/or amine compounds. In a specific embodiment, the at least one neutralizing agent comprises i) mono and/or divalent metal compounds and ii) ammonia compounds and/or amine compounds.
1. A golf ball comprising a core, an outer layer and at least one adhesion promoting coating disposed between the core and the outer layer, wherein:
the core comprises a rubber composition comprising at least one zinc-containing and/or magnesium-containing component;
the outer layer comprises at least one ionomer; and
the at least one adhesion promoting coating comprises a waterborne dispersion comprised of at least one ethylene acid copolymer having an acid content of at least 15% by weight;
wherein the copolymer is at least partially neutralized with one or more neutralizing agent;
wherein at least one neutralizing agent comprises an amine compound; and wherein the amine compound comprises dicyclohexylamine and/or aminomethylpropanol.
2. The golf ball of claim 1 , wherein at least one other neutralizing agent comprises a metal cation source comprising monovalent metal compounds and/or divalent metal compounds selected from zinc, calcium, magnesium, copper, manganese, nickel, cobalt, sodium, potassium, lithium, and combinations thereof.
3. The golf ball of claim 2 , wherein the metal cation source consists of divalent metal compounds.
4. The golf ball of claim 2 , wherein the adhesion promoting coating contains about 15 wt. % to about 30 wt. % solids.
5. The golf ball of claim 2 , wherein the total amount of neutralizing agent included in the adhesion promoting coating is from about 1.50 pbw to about 5.50 pbw.
6. The golf ball of claim 5 , wherein 10% to 40% of the acid groups of the acid copolymer are neutralized.
7. The golf ball of claim 5 , wherein the adhesion promoting coating has a drying temperature that is above ambient air temperature.
8. The golf ball of claim 7 , wherein the drying temperature is from 120° F. to less than 170° F.
9. The golf ball of claim 5 , wherein the adhesion promoting coating has a drying temperature of ambient air temperature.
10. The golf ball of claim 5 , wherein:
the core has: a diameter of 1.40 inches to 1.63 inches; a compression of from 10 DCM to 100 DCM; a center hardness of from 20 Shore C to 75 Shore C; a surface hardness of from 40 Shore C to 95 Shore C; wherein the center hardness is less than the surface hardness by at least 15 Shore C hardness points; and
the adhesion promoting coating is an ethylene acrylic acid dispersion having an acid content of at least 19% by weight; and
the outer layer is a casing layer comprised of a partially or fully-neutralized ionomer material that is neutralized by at least one metal compound selected from the group of Zn, Na, K, Mg, Li and Ca; and
the golf ball additionally comprises a polyurethane cover layer.
11. The golf ball of claim 5 , wherein:
the rubber composition of the core is a polybutadiene blend of one or more high cis polybutadiene rubbers having a Mooney viscosity of 35 to 70 and synthesized using cobalt, neodymium, or nickel catalyst; and
the core has: a diameter of 1.47 inches to 1.63 inches; a specific gravity of greater than 1.0; a compression of from 10 DCM to 120 DCM; a coefficient of restitution of at least 0.770; a center hardness of from 20 Shore C to 75 Shore C; and a surface hardness of from 40 Shore C to 95 Shore C; wherein the center hardness is less than the surface hardness by at least 15 Shore C hardness points; and
the adhesion promoting coating is an ethylene acrylic acid dispersion having an acid content of at least 22% by weight; and
the outer layer is an outer cover layer comprised of an ionomer material and having a surface hardness of 55 D or greater.
12. The golf ball of claim 5 , wherein the outer surface of the core is not surface-treated with any different adhesion promoter; and
wherein none of the adhesion promoting coating and the outer layer is surface-treated with any different adhesion promoter at an interface between the adhesion promoting coating and the outer layer.