Golf balls having a cover layer formed from an ionomer and metallocene-catalyzed polyolefin blend and methods of making same
View Patent ↗The disclosed invention provides a golf ball including a core and a cover of at least two layers, wherein the at least one cover layer includes an inner cover layer of at least one ionomer resin and an outer cover formed from a polymer blend including at least one grafted metallocene-catalyzed polymer and at least one ionomer neutralized with a metal cation, and optionally, a non-grafted metallocene-catalyzed polymer.
1. A golf ball comprising:
a core comprising polybutadiene and substantially free of organic sulfide;
an inner cover having at least one layer comprising a material having a first Shore D hardness formed over the core and comprising at least two thermoplastic materials, each neutralized with a different metal cation, and wherein the inner cover is substantially free of metallocene-catalyzed polymer; and
an outer cover having at least one layer comprising a polymer blend having a second Shore D hardness less than the first Shore D hardness, disposed about the inner cover, wherein the polymer blend comprises at least one grafted metallocene-catalyzed polymer, a non-ionomeric material comprising an acid-containing ethylene copolymer, and at least two ionomer resins, each neutralized with a different metal cation.
2. The golf ball of claim 1 , wherein the polymer blend comprises about 30 percent by weight or greater of the at least one grafted metallocene-catalyzed polymer.
3. The golf ball of claim 1 , wherein the at least one grafted metallocene-catalyzed polymer has been functionalized by grafting an ethylenically-unsaturated monomer onto the at least one metallocene-catalyzed polymer using a post-polymerization reaction.
4. The golf ball of claim 1 , wherein the core is fluid-filled.
5. The golf ball of claim 1 , wherein the golf ball further comprises at least one intermediate layer between the core and the inner cover layer.
6. The golf ball of claim 5 , wherein the intermediate layer is a tensioned elastomeric layer.
7. The golf ball of claim 1 , wherein the acid-containing ethylene copolymer comprises a copolymer represented by the following structure:
where x=50 to 99 percent, y=1 to 50 percent, z=0 to 49 percent, R 1 is H or CH 3 , R 2 is an alkyl group, and n ranges from 0 to 12.
8. The golf ball of claim 7 , wherein the acid-containing ethylene copolymer comprises about 10 to about 15 percent methacrylic acid.
9. A golf ball comprising a core, a layer disposed about the core, and a cover, wherein at least one of the core, the layer, or the cover is formed of a blend comprising:
at least one ionomer;
at least one grafted metallocene-catalyzed polymer; and
at least one non-ionomeric material comprising an acid-containing ethylene copolymer.
10. The golf ball of claim 9 , wherein the blend is present in the cover.
11. The golf ball of claim 10 , wherein the layer comprises at least one ionomer.
12. The golf ball of claim 11 , wherein the layer is substantially free of metallocene-catalyzed polymer.
13. The golf ball of claim 9 , wherein the at least one ionomer is present in an amount of about 99 to about 25 parts per hundred of the blend, wherein the at least one grafted metallocene-catalyzed polymer blend is present in an amount of about 1 to about 75 parts per hundred of the blend, and wherein the at least one non-ionomeric material is present in an amount of about 1 to about 70 parts per hundred of the blend.
14. The golf ball of claim 13 , wherein the at least one ionomer is present in an amount of about 90 to about 70 parts per hundred of the blend, wherein the at least one grafted metallocene-catalyzed polymer blend is present in an amount of about 10 to about 30 parts per hundred of the blend, and wherein the at least one non-ionomeric material is present in an amount of about 1 to about 20 parts per hundred of the blend.
15. The golf ball of claim 9 , wherein the layer has a hardness from about 65 Shore D to 80 Shore D and the cover has a second hardness is about 45 Shore D to 60 Shore D.
16. The golf ball of claim 9 , wherein the acid-containing ethylene copolymer comprises a copolymer represented by the following structure:
where x=50 to 99 percent, y=1 to 50 percent, z=0 to 49 percent, R 1 is H or CH 3 , R 2 is an alkyl group, and n ranges from 0 to 12.
17. The golf ball of claim 16 , wherein the acid-containing ethylene copolymer comprises about 10 to about 15 percent methacrylic acid.