Compositions containing transparent polyamides for use in making golf balls

Abstract

Multi-layered golf balls having at least one layer made of a polyamide composition containing a transparent polyamide polymer are provided. The transparent polyamide may be blended with other transparent or non-transparent polyamides. Thermoplastic polyamide elastomers such as polyether-amide block copolymers may be used. In one version, the composition comprises a blend of transparent polyamide, acid anhydride-modified polyolefin, and plasticizer. The golf ball includes a core having at least one layer and a cover having at least one layer. The polyamide composition may be used to form any core, cover, or other layer in the golf ball. In one version, the polyamide composition is used to form the inner cover layer.

We claim: 
     
         1 . A golf ball, comprising:
 a) dual core comprising an inner and outer core layer, the inner core having an outer surface and geometric center and the outer core layer having an outer surface and inner surface; the inner core comprising a polyamide composition, the polyamide composition comprising about 40 to about 100% by weight transparent polyamide polymer; and the outer core layer comprising a rubber composition,
 wherein the center of the inner core and surface of the outer core layer each has a hardness, and the surface hardness of the outer core layer is greater than the center hardness of the inner core; and 
   b) a cover having at least one layer disposed about the core.   
     
     
         2 . The golf ball of  claim 1 , wherein the polyamide composition further comprises about 1 to about 60% by weight of an acid anhydride-modified polyolefin. 
     
     
         3 . The golf ball of  claim 1 , wherein the polyamide composition further comprises a plasticizer. 
     
     
         4 . The golf ball of  claim 1 , wherein the center hardness of the inner core is about 15 Shore D or greater and the surface hardness of the outer core is about 40 Shore D or greater, the surface hardness of the outer core layer being greater than the center hardness of the inner core. 
     
     
         5 . The golf ball of  claim 1 , wherein the polyamide composition comprises a transparent polyether-amide block copolymer. 
     
     
         6 . The golf ball of  claim 1 , wherein the transparent polyamide has a glass transition temperature in the range of about 75° to about 160° C. 
     
     
         7 . The golf ball of  claim 1 , wherein the transparent polyamide has a Charpy notched impact-resistance of at least about 15 kJ/m 2  at 23° C. 
     
     
         8 . A golf ball, comprising:
 a) dual core comprising an inner and outer core layer, the inner core having an outer surface and geometric center and the outer core layer having an outer surface and inner surface; the inner core comprising a polyamide composition, the polyamide composition comprising about 40 to about 100% by weight transparent polyamide polymer; and the outer core layer comprising a rubber composition,
 wherein the center of the inner core and surface of the outer core layer each has a hardness, and the surface hardness of the outer core layer is greater than the center hardness of the inner core and the inner core has a Coefficient of Restitution of at least about 0.700; a Compression of at least about 90; and a Shore D surface hardness of about 60 to about 80; and 
   b) a cover having at least one layer disposed about the core.   
     
     
         9 . The golf ball of  claim 8 , wherein the polyamide composition further comprises about 1 to about 60% by weight of an acid anhydride-modified polyolefin. 
     
     
         10 . The golf ball of  claim 8 , wherein the polyamide composition further comprises a plasticizer. 
     
     
         11 . The golf ball of  claim 8 , wherein the center hardness of the inner core is about 15 Shore D or greater and the surface hardness of the outer core is about 40 Shore D or greater, the surface hardness of the outer core layer being greater than the center hardness of the inner core. 
     
     
         12 . The golf ball of  claim 8 , wherein the polyamide composition comprises a transparent polyether-amide block copolymer. 
     
     
         13 . The golf ball of  claim 8 , wherein the transparent polyamide has a glass transition temperature in the range of about 75° to about 160° C. 
     
     
         14 . The golf ball of  claim 8 , wherein the transparent polyamide has a Charpy notched impact-resistance of at least about 15 kJ/m 2  at 23° C. 
     
     
         15 . A golf ball, comprising:
 a) dual core comprising an inner and outer core layer, the inner core having an outer surface and geometric center and the outer core layer having an outer surface and inner surface; the inner core comprising a polyamide composition, the polyamide composition comprising a blend of transparent polyamide polymer and ethylene acid copolymer ionomer; and the outer core layer comprising a rubber composition,
 wherein the center of the inner core and surface of the outer core layer each has a hardness, and the surface hardness of the outer core layer is greater than the center hardness of the inner core; and 
   b) a cover having at least one layer disposed about the core.