Multi-piece golf ball comprising low hardness gradient core
View Patent ↗A golf ball includes a single core formed from a substantially homogenous rubber composition, an inner cover disposed about the core, and an outer cover. The inner cover includes an ionomeric material and has a hardness of about 60 Shore D or greater. The outer cover layer is disposed about the inner cover layer, is formed from a castable polyurea or polyurethane, and has a material hardness of about 60 Shore D or less. The outer surface of the core has a trans content of about 12% or less and a hardness of about 71 to 88 Shore C, the geometric center of the core has a trans content of about 10% or less and a hardness of about 70 to 80 Shore C, and 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.
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 an ionomeric material and having a material hardness of about 60 Shore D or greater; and
an outer cover layer disposed about the inner cover layer, the outer cover comprising a polyurea or a polyurethane and having a material hardness of about 60 Shore D or less;
wherein the outer surface has a trans content of about 12% or less and a hardness of about 68 to 88 Shore C, the geometric center has a trans content of about 10% or less and a hardness of about 70 to 80 Shore C, and 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.
2. The golf ball of claim 1 , wherein the positive hardness gradient is about 2 to 8 Shore C.
3. The golf ball of claim 2 , wherein the positive hardness gradient is about 2.5 to 7 Shore C.
4. The golf ball of claim 1 , wherein the core has an outer diameter of about 1.45 to about 1.62 inches.
5. The golf ball of claim 4 , wherein the core has an outer diameter of about 1.50 to about 1.58 inches.
6. The golf ball of claim 1 , wherein the hardness of the core geometric center is about 72 to 78 Shore C.
7. The golf ball of claim 1 , wherein the hardness of the core surface is about 71 to 80 Shore C.
8. The golf ball of claim 7 , wherein core surface hardness is about 73 to 78 Shore C.
9. The golf ball of claim 1 , wherein the outer surface has a trans content of about 10% or less and the geometric center has a trans content of about 8% or less.
10. The golf ball of claim 1 , further comprising an intermediate layer disposed between the inner cover layer and the outer cover layer, the intermediate layer comprising a thermoplastic ionomers having a hardness of about 85 Shore C or greater.
11. The golf ball of claim 10 , wherein a sphere comprising the core, inner cover layer, and the intermediate layer has an outer diameter of about 1.25 to 1.62 inches.
12. The golf ball of claim 1 , further comprising an intermediate layer disposed between the inner cover layer and the outer cover layer, the intermediate layer comprising a thermoplastic ionomers having a hardness of about 85 Shore C or less.
13. The golf ball of claim 12 , wherein a sphere comprising the core, inner cover layer, and the intermediate layer has an outer diameter of about 1.25 to 1.62 inches.
14. A golf ball comprising:
a single core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition; and
an outer cover layer disposed about the single core, the outer cover comprising a polyurea or a polyurethane and having a material hardness of about 60 Shore D or less;
wherein the outer surface has a trans content of about 12% or less and a hardness of about 68 to 88 Shore C, the geometric center has a trans content of about 10% or less and a hardness of about 70 to 80 Shore C, and 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.
15. A golf ball comprising:
a single core having an outer surface and a geometric center and being formed from a substantially homogenous rubber composition; and
an outer cover layer disposed about the single core, the outer cover comprising an ionomeric material and having a material hardness of about 60 Shore D or greater;
wherein the outer surface has a trans content of about 12% or less and a hardness of about 68 to 88 Shore C, the geometric center has a trans content of about 10% or less and a hardness of about 70 to 80 Shore C, and 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.