Multi-layer cover golf ball having a high acid casing layer
View Patent ↗A golf ball includes a single core having an outer surface and a geometric center. The core is formed from a substantially homogenous rubber composition. An inner cover layer is disposed about the core, the inner cover including a high-acid ionomer and having a material hardness of about 66 to 75 Shore D. The high-acid ionomer has an acid content of about 16% or greater. An outer cover layer is disposed about the inner cover layer, the outer cover including a polyurethane and having a material hardness of about 38 Shore D to about 56 Shore D. The core surface hardness is from 0 Shore C to 15 Shore C lower than the geometric center hardness to define a hardness gradient.
1. A golf ball comprising:
a single core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition;
an inner cover layer disposed about the core, the inner cover comprising a high-acid ionomer and having a material hardness of about 66 to 75 Shore D, the high-acid ionomer having an acid content of about 16% or greater; and
an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurethane and having a material hardness of about 38 Shore D to about 56 Shore D;
wherein the core surface hardness is greater than the geometric center hardness by about 1 to 10 Shore C to define a shallow positive hardness gradient; and wherein the geometric center of the core has a trans content of about 1% to 10% and the outer surface of the core has a trans content of about 5% to 15%.
2. The golf ball of claim 1 , wherein the positive hardness gradient is about 1 to 5 shore C.
3. The golf ball of claim 1 , wherein the positive hardness gradient is about 2 to 8 Shore C.
4. The golf ball of claim 3 , wherein the positive hardness gradient is about 2.5 to 7 Shore C.
5. The golf ball of claim 1 , wherein the geometric center of the core has a trans content of about 2% to 9%.
6. The golf ball of claim 5 , wherein the geometric center of the core has a trans content of about 4% to 8%.
7. The golf ball of claim 1 , wherein the outer surface of the core has a trans content of about 7% to 12%.
8. The golf ball of claim 7 , wherein the outer surface of the core has a trans content of about 8% to 10%.
9. The golf ball of claim 1 , wherein a half-radius point located between the geometric center and the outer surface of the core has a trans content of about 5% to 16%.
10. The golf ball of claim 9 , wherein the half-radius point has a trans content of about 7% to 13%.