Multi-layer golf ball
View Patent ↗Golf balls consisting of a dual core and a dual cover are disclosed. The surface hardness of the outer core layer is greater than the material hardness of the inner cover layer, and is preferably 75 Shore C or greater.
1. A golf ball consisting of:
a center formed from a first rubber composition and having a diameter of from 1.20 inches to 1.30 inches, a center hardness of 50 Shore C or greater, and a compression of from 20 to 40;
an outer core layer formed from a second rubber composition and having a surface hardness of 90 Shore C or greater;
an inner cover layer formed from a thermoplastic composition comprising a blend of ionomer resin and a maleic anhydride-grafted polymer and having a material hardness of less than 95 Shore C; and
an outer cover layer formed from a thermosetting polyurethane or polyurea composition;
wherein the center has a surface hardness substantially equal to the center hardness;
wherein the surface hardness of the outer core layer is at least 20 Shore C units greater than the center hardness; and
wherein the surface hardness of the outer core layer is greater than the material hardness of the inner cover layer.
2. The golf ball of claim 1 , wherein the surface hardness of the outer core layer is greater than the material hardness of the outer cover layer.
3. The golf ball of claim 1 , wherein the material hardness of the inner cover layer is from 80 Shore C to 90 Shore C.
4. The golf ball of claim 1 , wherein the material hardness of the inner cover layer is from 84 Shore C to 90 Shore C.