Golf ball compositions
View Patent ↗Disclosed herein are polyurethane golf ball compositions. The compositions are prepared by adding a UV absorber to a polyol prior to reacting the polyol with an isocyanate to form a prepolymer, which is then reacted with a curing agent to form the polyurethane.
1. A golf ball comprising:
an inner core layer formed from a diene rubber composition and having a diameter of from 0.950 inches to 1.015 inches, an Atti compression of 30 or less, a center Shore C hardness of from 65 to 75, a surface Shore C hardness of from 50 to 65, and a zero hardness gradient or a negative hardness gradient wherein the difference between the Shore C hardness of the outer surface of the inner core layer and the Shore C hardness of the center of the inner core layer is from −15 to −5;
an outer core layer formed from a diene rubber composition and having a thickness of from 0.250 inches to 0.300 inches and an outer surface Shore C hardness of from 85 to 95;
an inner cover layer formed from an ionomer composition and having a thickness of from 0.030 inches to 0.040 inches and an outer surface Shore C hardness of 93 or greater;
an outer cover layer formed from a polyurethane composition and having a thickness of from 0.030 inches to 0.035 inches and an outer surface Shore C hardness of from 75 to 90;
a pigmented solvent-borne primer coat; and
a solvent-borne top coat;
wherein the polyurethane outer cover layer composition comprises a reaction product of a prepolymer and a curing agent, wherein the prepolymer is a reaction product of a polyol mixture and a diisocyanate, and wherein the polyol mixture comprises a UV absorber in an amount such that the final polyurethane comprises from 4 wt % to 6 wt % of the UV absorber; and
wherein a core assembly consisting of the inner core layer and the outer core layer has an Atti compression of from 80 to 95.
2. The golf ball of claim 1 , wherein the UV absorber is 2-(2H-benzotriazol-2-yl)-4,6-ditertpentylphenol.
3. The golf ball of claim 1 , wherein the outer cover layer of the golf ball comprises a plurality of dimples having an effective edge angle and an edge radius, wherein the effective edge angle is greater than and the edge radius is less than that of a corresponding golf ball identical in all respects except that the primer coat is a pigmented waterborne primer coat.