Highly-neutralized acid polymers and their use in golf balls
View Patent ↗The present invention is directed to a golf ball having at least one layer which includes a polymer composition containing at least 50 wt % of an acid polymer and at least 0.5 wt % of a polylactic acid, wherein the weight percentages are based on the total polymeric weight of the polymer composition. At least 70% of the acid groups of the acid polymer are neutralized by a cation source or a metal salt thereof.
1. A golf ball having at least one layer formed from a polymer composition, the polymer composition comprising:
at least 50 wt %, based on the total polymeric weight of the polymer composition, of an acid polymer having acid groups, wherein at least 70% of the acid groups are neutralized; and
at least 0.5 wt %, based on the total polymeric weight of the polymer composition, of a polylactic acid.
2. The golf ball of claim 1 , wherein at least 90% of the acid groups of the acid polymer are neutralized.
3. The golf ball of claim 1 , wherein at least 95% of the acid groups of the acid polymer are neutralized.
4. The golf ball of claim 1 , wherein 100% of the acid groups of the acid polymer are neutralized.
5. The golf ball of claim 1 , wherein the polymer composition is substantially free of fatty acids and their salts.
6. The golf ball of claim 1 , wherein the polymer composition has a melt flow index of from 1.0 g/10 min to 5.0 g/10 min.
7. The golf ball of claim 1 , wherein the polymer composition consists essentially of:
at least 50 wt %, based on the total polymeric weight of the polymer composition, of the acid polymer;
at least 0.5 wt %, based on the total polymeric weight of the polymer composition, of the polylactic acid; and
from 0 wt % to 60 wt %, based on the total weight of the polymer composition, of an inorganic additive.
8. The golf ball of claim 1 , wherein the golf ball is a multi-layer golf ball, and wherein the polymer composition is present in an intermediate layer.
9. The golf ball of claim 8 , wherein the intermediate layer is an inner cover layer having a thickness of from 0.010 in to 0.060 in and a material hardness of from 30 Shore D to 80 Shore D.
10. The golf ball of claim 1 , wherein the golf ball comprises a center and a cover, and wherein the polymer composition is present in the center.
11. The golf ball of claim 1 , wherein the polymer composition has a flexural modulus of from 5,000 psi to 125,000 psi.
12. The golf ball of claim 1 , wherein the polymer composition has a notched izod impact strength of at least 2 ft·lb/in.
13. A golf ball having at least one layer formed from a polymer composition, the polymer composition consisting essentially of:
at least 50 wt %, based on the total polymeric weight of the polymer composition, of an acid polymer having acid groups, wherein at least 70% of the acid groups are neutralized;
at least 0.5 wt %, based on the total polymeric weight of the polymer composition, of a polylactic acid; and
from 0 wt % to 60 wt %, based on the total weight of the polymer composition, of an inorganic additive;
wherein the polymer composition has a melt flow index of from 1.0 g/10 min to 5.0 g/10 min.
14. The golf ball of claim 13 , wherein at least 90% of the acid groups of the acid polymer are neutralized.
15. The golf ball of claim 13 , wherein at least 95% of the acid groups of the acid polymer are neutralized.
16. The golf ball of claim 13 , wherein 100% of the acid groups of the acid polymer are neutralized.
17. The golf ball of claim 13 , wherein the polymer composition has a flexural modulus of from 5,000 psi to 125,000 psi and a notched izod impact strength of at least 2 ft·lb/in.