Golf ball comprising a very-low melt flow inner cover layer composition
A golf ball including a core; an inner cover layer formed from a thermoplastic composition and having a thickness of about 0.005 inches to 0.40 inches and a surface hardness of about 60 Shore D or greater; and an outer cover layer formed from a thermoset material and having a thickness of about 0.01 inches to 0.05 inches and a surface hardness of about 60 Shore D or less. The thermoplastic composition has a first melt flow index at 280° C. under a 10-kg load of less than about 35 g/10 min and a second melt flow index at 265° C. under a 5-kg load of less than about 10 g/10 min.
1. A golf ball comprising:
a core;
an inner cover layer comprising a first thermoplastic composition and having a thickness of about 0.005 inches to about 0.40 inches and a surface hardness of about 70 Shore D or less; and
an outer cover layer comprising a thermoplastic polyurethane and having a thickness of about 0.01 inches to about 0.075 inches and a surface hardness of about 20 Shore D to about 60 Shore D;
wherein the first thermoplastic composition comprises a first melt flow index at 280° C. under a 10-kg load of less than about 35 g/10 min and a second melt flow index at 265° C. under a 5-kg load of less than about 10 g/10 min.
2. The golf ball of claim 1 , wherein the first melt flow index is about 20 g/10 min or less.
3. The golf ball of claim 2 , wherein the first melt flow index is about 10 g/10 min or less.
4. The golf ball of claim 3 , wherein the second melt flow index is about 5 g/10 min or less.
5. The golf ball of claim 1 , wherein the first thermoplastic composition has a third melt flow index at 190° C. under a 2.16-kg load of less than about 2 g/10 min.
6. The golf ball of claim 5 , wherein the third melt flow index at is less than about 1 g/10 min.
7. The golf ball of claim 1 , wherein the first thermoplastic composition comprises an ionomer.
8. The golf ball of claim 7 , wherein the first thermoplastic composition comprises a higher-melting-temperature thermoplastic resin.
9. The golf ball of claim 7 , wherein the first thermoplastic composition comprises a reactive polymer.
10. The golf ball of claim 7 , wherein the ionomer is neutralized by a metal cation to 80 wt % or greater.
11. The golf ball of claim 10 , wherein the ionomer is neutralized by a metal cation to 90 wt % or greater.
12. The golf ball of claim 1 , wherein the first thermoplastic composition comprises an amine or a peroxide compound.
13. The golf ball of claim 1 , wherein the core comprises an inner core and an outer core layer.
14. A golf ball comprising:
a core;
an inner cover layer comprising a first thermoplastic composition and having a thickness of about 0.005 inches to about 0.40 inches and a surface hardness of about 70 Shore D or less; and
an outer cover layer comprising a second thermoplastic material and having a thickness of about 0.01 inches to about 0.075 inches and a surface hardness of about 20 Shore D to about 60 Shore D;
wherein the first thermoplastic composition comprises a first melt flow index at 280° C. under a 10-kg load of less than about 35 g/10 min and a second melt flow index at 265° C. under a 5-kg load of less than about 10 g/10 min.
15. The golf ball of claim 14 , wherein the second thermoplastic composition comprises a thermoplastic polyurethane.
16. The golf ball of claim 14 , wherein the core comprises an inner core and an outer core layer.