Propylene-Based Fully-Neutralized Acid or Anhydride Polymers for Use in Golf Balls

1 . A golf ball comprising a core, a cover layer, and an outer core layer disposed between the core and the cover layer, the outer core layer having a thickness of 0.1 inches to 0.5 inches and comprising a polymer composition formed from an anhydride-grafted polypropylene having the structure:

where x=99-85; y=1-15; z=0-40; and R 1 is a C 1-12 linear or branched alkyl group, wherein the anhydride group is 100%-neutralized in the presence of sufficient cation source, a salt of the organic acid, and, optionally, an organic acid to form a reaction product having the structure:

where x=99-85; y=1-15; z=0-40; R 1 is a C 1-12 linear or branched alkyl group; and M + and M ++ are the cation source.

2 . The golf ball of claim 1 , wherein the anhydride comprises maleic anhydride, fumaric anhydride, itaconic anhydride, or derivatives thereof.

3 . The golf ball of claim 1 , wherein the cation source is selected from a group consisting of metal cations of lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, and zinc.

4 . The golf ball of claim 1 , wherein the salt of an organic acid comprises an organic acid selected from the group consisting of aliphatic organic acids, aromatic organic acids, saturated mono- or multi-functional organic acids, unsaturated mono- or multi-functional organic acids, and multi-unsaturated mono- or multi-functional organic acids.

5 . The golf ball of claim 1 , wherein the salt of an organic acid comprises stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid or dimerized derivatives thereof.

6 . The golf ball of claim 1 , wherein the salt of an organic acid comprises a cation selected from the group consisting of barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, and calcium.

7 . The golf ball of claim 1 , wherein the cover comprises polyurethane, polyurea, epoxy resins, polyamides, polyesters, polycarbonates, or a copolymer comprising urethane and urea segments.

8 . The golf ball of claim 1 , wherein the core comprises polybutadiene.

9 . The golf ball of claim 1 , wherein the core comprises a polymer comprising a copolymer or terpolymer of ethylene and an a,β-unsaturated carboxylic acid, the acid being fully-neutralized by a salt of an organic acid, a cation source, or a salt of the organic acid.

10 . The golf ball of claim 1 , wherein the polypropylene is a homopolymer or a copolymer.

11 . A golf ball comprising a core, an outer cover layer, and an inner cover layer disposed between the core and the outer cover layer, the inner cover layer having a thickness of 0.02 inches to 0.05 inches and comprising a polymer composition formed from an anhydride-grafted polypropylene having the structure:

where x=99-85; y=1-15; z=0-40; and R 1 is a C 1-12 linear or branched alkyl group, wherein the anhydride group is 100%-neutralized in the presence of sufficient cation source, a salt of the organic acid, and, optionally, an organic acid, to form a reaction product having the structure:

where x=99-85; y=1-15; z 0-40; R 1 is a M 1-12 linear or branched alkyl group; and M + and M ++ are the cation source.

12 . The golf ball of claim 11 , wherein the anhydride comprises maleic anhydride, fumaric anhydride, itaconic anhydride, or hydrogen, methyl, ethyl, or propyl derivatives thereof.

13 . The golf ball of claim 11 , wherein an acid moiety is grafted onto the polypropylene.

14 . The golf ball of claim 13 , wherein the acid moiety comprises acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, or derivates thereof.

15 . The golf ball of claim 11 , wherein the cation source is selected from a group consisting of metal cations of lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, and zinc.

16 . The golf ball of claim 11 , wherein the salt of an organic acid comprises an organic acid selected from the group consisting of aliphatic organic acids, aromatic organic acids, saturated mono- or multi-functional organic acids, unsaturated mono- or multi-functional organic acids, and multi-unsaturated mono- or multi-functional organic acids.

17 . The golf ball of claim 11 , wherein the salt of an organic acid comprises stearic acid, behenic acid, erucic acid, oleic acid, linoelic acid or dimerized derivatives thereof.

18 . The golf ball of claim 11 , wherein the salt of an organic acid comprises a cation selected from the group consisting of barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, and calcium.

19 . The golfball of claim 11 , wherein the core diameter is 1.0 inches to 1.58 inches.

20 . The golf ball of claim 11 , wherein the cover comprises polyurethane, polyurea, epoxy resins, polyamides, polyesters, polycarbonates, or a copolymer comprising urethane and urea segments.

21 . The golf ball of claim 11 , wherein the core comprises polybutadiene.

22 . The golf ball of claim 11 , wherein the core comprises a polymer comprising a copolymer or terpolymer of ethylene and an a,β-unsaturated carboxylic acid, the acid being fully-neutralized by a salt of an organic acid, a cation source, or a salt of the organic acid.

23 . A golf ball comprising a core, a cover layer, and an outer core layer disposed between the core and the cover layer, the outer core layer having a thickness of 0.1 inches to 0.5 inches and comprising a polymer composition formed from an α,β-unsaturated carboxylic acid-grafted polypropylene having the structure:

where x=99-85, y=1-15, z=0-40, and R 1 is a C 1-12 linear or branched alkyl group, wherein the carboxylic acid group is 100%-neutralized in the presence of sufficient cation source, a salt of the organic acid, and, optionally, an organic acid to form a reaction product having the structure:

where x=99-85; y=1-15; z 0-40; R 1 is a C 1-12 linear or branched alkyl group; and M + is the cation source.