MULTI-LAYER GOLF BALL
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 and a center hardness of 50 Shore C or greater;
an outer core layer formed from a second rubber composition and having a surface hardness of 75 Shore C or greater;
an inner cover layer formed from a thermoplastic composition and having a material hardness less than the surface hardness of the outer core layer; and
an outer cover layer formed from a polyurethane or polyurea composition.
2 . The golf ball of claim 1 , wherein the surface hardness of the outer core layer is at least 20 Shore C units greater than the center hardness.
3 . The golf ball of claim 1 , wherein the outer cover layer has a material hardness less than the surface hardness of the outer core layer.
4 . The golf ball of claim 1 , wherein the center hardness is from 55 Shore C to 70 Shore C.
5 . The golf ball of claim 1 , wherein the center has a surface hardness of 65 Shore C or greater.
6 . The golf ball of claim 1 , wherein the center has a surface hardness of 70 Shore C or greater.
7 . The golf ball of claim 1 , wherein the surface hardness of the outer core layer is at least 30 Shore C units greater than the center hardness.
8 . The golf ball of claim 1 , wherein the inner cover layer has a material hardness of from 80 Shore C to 95 Shore C.
9 . The golf ball of claim 1 , wherein the inner cover layer has a material hardness of from 84 Shore C to 92 Shore C.
10 . The golf ball of claim 1 , wherein the center has a center hardness of from 50 Shore C to 80 Shore C, the center has a surface hardness of 70 Shore C or greater, the outer core layer has a surface hardness of greater than 80 Shore C, and the surface hardness of the outer core layer is at least 30 Shore C units greater than the center hardness.
11 . The golf ball of claim 10 , wherein the surface hardness of the outer core layer is 85 Shore C or greater, and the inner cover layer has a material hardness of 90 Shore C or less.
12 . The golf ball of claim 10 , wherein the surface hardness of the outer core layer is 87 Shore C or greater, and the inner cover layer has a material hardness of 90 Shore C or less.
13 . The golf ball of claim 12 , wherein the inner cover layer has a material hardness of from 85 Shore C to 90 Shore C.
14 . The golf ball of claim 10 , wherein the surface hardness of the outer core layer is 90 Shore C or greater, and the inner cover layer has a material hardness of 90 Shore C or less.
15 . The golf ball of claim 1 , wherein the center has a compression of 40 or less.
16 . The golf ball of claim 15 , wherein the core has an overall dual core compression of from 75 to 90.
17 . The golf ball of claim 1 , wherein the core has an overall dual core diameter of from 1.52 inches to 1.59 inches.
18 . 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 from 50 Shore C to 70 Shore C, and a surface hardness of from 60 Shore C to 85 Shore C;
an outer core layer formed from a second rubber composition and having a surface hardness of from 80 Shore C to 95 Shore C;
an inner cover layer formed from a thermoplastic composition 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 surface hardness of the center is at least 10 Shore C units greater than 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.
19 . The golf ball of claim 18 , wherein the surface hardness of the outer core layer is greater than the material hardness of the outer cover layer.
20 . The golf ball of claim 18 , wherein the material hardness of the inner cover layer is from 80 Shore C to 95 Shore C.
21 . The golf ball of claim 18 , wherein the material hardness of the inner cover layer is from 84 Shore C to 92 Shore C.