Thermoplastic multi-layer golf ball

Abstract

A thermoplastic multi-layer golf ball has a core center comprising a first thermoplastic material having a first flexural modulus; a core layer disposed radially outward from the core center, wherein the core layer comprises a second thermoplastic material having a second flexural modulus; and a cover disposed radially outward of the core layer, wherein the cover comprises a third thermoplastic material having a third flexural modulus. Either the second flexural modulus is greater than the first flexural modulus or both are up to about 15,000 psi. The first flexural modulus is greater than the third flexural modulus or the third flexural modulus is up to about 5,000 psi.

What is claimed is: 
     
         1 . A golf ball, comprising:
 a core center comprising a first thermoplastic material having a first flexural modulus;   a core layer disposed radially outward from the core center, wherein the core layer comprises a second thermoplastic material having a second flexural modulus; and   a cover disposed radially outward from the core layer, wherein the cover comprises a third thermoplastic material having a third flexural modulus;   
       wherein the second flexural modulus is greater than the first flexural modulus and the first flexural modulus is greater than the third flexural modulus. 
     
     
         2 . A golf ball according to  claim 1 , wherein the second thermoplastic material comprises a first elastomer and a second elastomer, and further wherein the third thermoplastic material is non-ionomeric. 
     
     
         3 . A golf ball according to  claim 1  or  claim 2 , wherein the golf ball is free from a thermoset rubber layer. 
     
     
         4 . A golf ball according to any one of  claims 1 - 3 , wherein at least one of the first thermoplastic material, the second thermoplastic material, and the third thermoplastic material comprises a member selected from the group consisting of ionomer resins, polyamide elastomers, polyurethane elastomers, thermoplastic polyester elastomers, and combinations thereof. 
     
     
         5 . A golf ball according to any one of  claims 1 - 4 , wherein the first flexural modulus is from about 1,000 psi to about 15,000 psi, the second flexural modulus is from about 6,000 psi to about 45,000 psi, or the third flexural modulus is from about 300 psi to about 10,000 psi. 
     
     
         6 . A golf ball according to any one of  claims 1 - 5 , wherein the second flexural modulus is at least three times the third flexural modulus. 
     
     
         7 . A golf ball according to any one of  claims 1 - 6 , wherein the second flexural modulus is at least 10 times the third flexural modulus. 
     
     
         8 . A golf ball according to any one of  claims 1 - 7 , further comprising a second core layer between the core layer and the cover, wherein the second core layer comprises a fourth thermoplastic material with a fourth flexural modulus greater than the second flexural modulus. 
     
     
         9 . A golf ball according to  claim 8 , wherein the fourth flexural modulus is from about 30,000 psi to about 120,000 psi. 
     
     
         10 . A golf ball according to  claim 8  or  claim 9 , wherein the fourth flexural modulus is at least three times the second flexural modulus and at least 30 times the third flexural modulus. 
     
     
         11 . A golf ball according to any one of  claims 1 - 10 , wherein the core layer has the lowest specific gravity among all layers. 
     
     
         12 . A golf ball according to any one of  claims 1 - 10 , wherein the core center has the lowest specific gravity among all layers. 
     
     
         13 . A golf ball according to any one of  claims 1 - 12 , wherein the core layer and the core center have a difference in specific gravity of at least about 0.1 g/cm 3 . 
     
     
         14 . A golf ball according to any one of  claims 1 - 12 , wherein the cover and the core center have a difference in specific gravity of at least about 0.1 g/cm 3 . 
     
     
         15 . A golf ball according to any one of  claims 1 - 14 , wherein the core center has a diameter of from 14 mm to 32 mm and a 10 kg to 130 kg compression deformation of at least about 3. 
     
     
         16 . A golf ball, comprising:
 a core center comprising a shell with a thickness of from about 1 mm to about 6 mm defining a interior space about 12 mm to about 24 mm in diameter, the interior space being filled with a fluid, wherein the shell comprises a first thermoplastic material having a first flexural modulus up to about 15,000 psi;   a core layer disposed radially outward from the core center, wherein the core layer has a thickness of at least about 4 mm and comprises a second thermoplastic material having a second flexural modulus up to about 15,000 psi and a specific gravity of at least about 1.1 g/cm 3 ; and   a cover disposed radially outward of the core layer, wherein the cover comprises a third thermoplastic material having a third flexural modulus up to about 5,000 psi;   
       wherein the second flexural modulus is greater than the first flexural modulus and the first flexural modulus is greater than the third flexural modulus. 
     
     
         17 . A golf ball according to  claim 16 , wherein the fluid is a liquid. 
     
     
         18 . A golf ball according to  claim 17 , wherein the liquid is selected from the group consisting of honey, mineral oil, and aqueous solutions of organic and inorganic materials. 
     
     
         19 . A golf ball according to  claim 16 , wherein the fluid is a gas. 
     
     
         20 . A golf ball according to  claim 19 , wherein the gas is pressurized. 
     
     
         21 . A golf ball, comprising:
 a core center having a diameter of from about 5 mm to about 18 mm, having a specific gravity of at least about 2 g/cm 3 , and comprising a first thermoplastic material having a first flexural modulus up to about 15,000 psi;   a core layer having a thickness of at least about 10 mm disposed radially outward from the core center, wherein the core layer comprises a second thermoplastic material having a second flexural modulus up to about 15,000 psi; and   a cover disposed radially outward of the core layer, wherein the cover comprises a third thermoplastic material having a third flexural modulus up to about 5,000 psi;   
       wherein the second flexural modulus is greater than the first flexural modulus, the first flexural modulus is greater than the third flexural modulus, and the specific gravity of the core center is higher than the sum of the specific gravities of the core layer and the cover.