Three-Cover-Layer Golf Ball Comprising Intermediate Layer Including A Plasticized Polyester Composition
A golf ball includes a core and a three-layer cover disposed adjacent the core. The three-layer cover includes an inner cover, an intermediate cover, and an outer cover. The inner cover includes a non-ionomeric E/Y copolymer where E is an olefin and Y is a carboxylic acid. The inner cover has a hardness of about 45 to 68 Shore D. The outer cover includes a castable thermoset polyurethane and has a hardness of about 40 to 62 Shore D. The intermediate cover layer, disposed between the inner and outer cover layers, is formed from a polyester composition including about 40 wt % to about 99 wt % of a polyester thermoplastic elastomer and about 1 wt % to about 60 wt % of a plasticizer.
1 . A golf ball comprising:
a core; and
a cover disposed adjacent the core, the cover comprising:
a non-ionomeric inner cover layer comprising an E/Y copolymer where E is an olefin and Y is a carboxylic acid, the non-ionomeric inner cover being disposed about the core and having a hardness of about 45 to 68 Shore D;
a castable thermoset polyurethane outer cover layer having a hardness from about 40 to 62 Shore D; and
an intermediate cover layer disposed between the inner cover layer and outer cover layer, the intermediate cover layer comprising a polyester composition comprising about 40 to 99 weight % of a polyester thermoplastic elastomer and about 10 to 60 weight % of a plasticizer.
2 . The golf ball of claim 1 , wherein the polyester composition further comprises an acid copolymer of ethylene and an α,β-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates; and a cation source present in an amount sufficient to neutralize from about 0 to about 100% of all acid groups present in the composition.
3 . The golf ball of claim 2 , wherein the acid groups of the acid copolymer of ethylene are neutralized by about 80% or greater.
4 . The golf ball of claim 1 , wherein the plasticizer comprises a fatty acid ester.
5 . The golf ball of claim 4 , wherein the fatty acid ester comprises an alkyl oleate.
6 . The golf ball of claim 5 , wherein the alkyl oleate comprises methyl oleate, ethyl oleate, propyl oleate, butyl oleate, or octyl oleate.
7 . The golf ball of claim 1 , wherein the intermediate layer hardness is greater than the inner cover layer hardness.
8 . The golf ball of claim 7 , wherein the intermediate layer hardness is greater than the inner cover layer hardness by at least 5 Shore D.
9 . The golf ball of claim 1 , wherein the intermediate layer hardness is greater than the outer cover layer hardness.
10 . The golf ball of claim 9 , wherein the intermediate layer hardness is greater than the outer cover layer hardness by at least 5 Shore D.
11 . The golf ball of claim 1 , wherein the core comprises a center and at least one outer core layer.
12 . The golf ball of claim 1 , wherein the non-ionomeric inner cover layer further comprises a polyester/polycarbonate blend, a polyester resin, an acetal resin, a polyamide resin, a polyetheramide resin, a polyester resin, a polyester elastomer, a liquid crystalline polyester, a polyester/polyamide blend, a poly(arylene ether)/polyester resin, or a polyimide.
13 . The golf ball of claim 1 , wherein the olefin is ethylene and the carboxylic acid is acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, or a combination thereof.
14 . The golf ball of claim 1 , wherein the polyester composition has a Charpy notched impact-resistance of about 15 kJ/m 2 or greater when measured at 23° C.
15 . The golf ball of claim 1 , wherein the polyester composition has a ratio of Charpy notched impact-resistance measured at 23° C. and measured at −30° C. of at least about 2.0.