Low compression golf balls having layers made from plasticized thermoplastic materials
Low compression, multi-piece golf balls containing a solid core and two or three-layered cover assemblies are provided. Preferably, the ball has a compression of less than 60 and more preferably less than 50. At least one cover layer is made of a plasticized thermoplastic composition. For example, two-layered and three-layered covers may be made. Preferably, the plasticized thermoplastic composition comprises: a) ethylene acid copolymer, b) plasticizer, and c) cation source. A fatty acid ester such as ethyl oleate or butyl oleate is preferably used as the plasticizer. The cover assembly has good impact durability and helps provide the ball with relatively high resiliency at given compressions.
1. A golf ball, comprising:
i) a core having at least one layer;
ii) an inner cover layer having a Shore D midpoint hardness in the range of about 55 to about 90; and
iii) an outer cover layer comprising a thermoplastic material, the outer cover being disposed about the inner cover layer and having a Shore D surface hardness in the range of about 15 to about 60, the thermoplastic material comprising:
a) an acid copolymer of ethylene and α,β-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;
b) a plasticizer, wherein the plasticizer is an alkyl oleate selected from the group consisting of methyl oleate, ethyl oleate, propyl oleate, butyl oleate, and octyl oleate, and mixtures thereof; and
c) a cation source present in an amount sufficient to neutralize from about 0 to about 100% of all acid groups present in the material; wherein the hardness of the outer cover layer is less than the hardness of the inner cover layer, and wherein the ball has a compression of less than 60.
2. The golf ball of claim 1 , wherein the thickness of the inner cover layer is in the range of about 0.020 to about 0.080 inches, and the thickness of the outer cover layer is in the range of about 0.006 to about 0.040 inches.
3. The golf ball of claim 1 , wherein the ball has a compression in the range of about 25 to about 55.
4. The golf ball of claim 1 , wherein the thermoplastic material comprises about 3 to about 50% by weight plasticizer.