Multilayered golf ball having whiskers and manufacturing method thereof

Abstract

A multilayered golf ball having inside whiskers and a method for manufacturing the same are provided. The method includes the steps of forming a ball core, forming an inner cover layer to cover the ball core, and forming an outer cover layer to cover the inner cover layer. The outer cover layer has a flexural modulus between 20 MPa and 600 MPa and the inner cover layer has a flexural modulus between 20 MPa and 400 MPa. The inner cover layer has a three-dimensional network structure that is formed by the whiskers, and the whiskers are in an amount between 1 wt % and 5 wt % of the total weight of the inner cover layer.

What is claimed is: 
     
         1 . A multilayered golf ball having inside whiskers comprising a ball core, an outer cover layer covering the ball core, and at least one inner cover layer disposed between the ball core and the outer cover layer, wherein the outer cover layer has a flexural modulus between 20 MPa and 600 MPa and the inner cover layer has a flexural modulus between 20 MPa and 400 MPa, the inner cover layer has a three-dimensional network structure that is formed by the whiskers, and the whiskers are in an amount between 1 wt % and 5 wt % of the total weight of the inner cover layer. 
     
     
         2 . The multilayered golf ball according to  claim 1 , wherein the whiskers are in an amount between 2.5 wt % and 3 wt % of the total weight of the inner cover layer. 
     
     
         3 . The multilayered golf ball according to  claim 1 , wherein the whiskers are zinc oxide whiskers. 
     
     
         4 . The multilayered golf ball according to  claim 1 , wherein the inner cover layer is formed from a highly neutralized acid polymer resin or a metal cation based low acid ionomer resin. 
     
     
         5 . The multilayered golf ball according to  claim 1 , wherein the outer cover layer is formed from a metal cation based low acid ionomer resin. 
     
     
         6 . The multilayered golf ball according to  claim 1 , wherein the ball core has a coefficient of restitution between 0.65 and 0.85. 
     
     
         7 . A method for manufacturing a multilayered golf ball having inside whiskers, comprising:
 forming a ball core;   forming an inner cover layer to cover the ball core, wherein the inner cover layer has a flexural modulus between 20 MPa and 400 MPa, the inner cover layer has a three-dimensional network structure that is formed by the whiskers, and the whiskers are in an amount between 1 wt % and 5 wt % of the total weight of the inner cover layer; and   forming an outer cover layer to cover the inner cover layer, wherein the outer cover layer has a flexural modulus between 20 MPa and 600 MPa.   
     
     
         8 . The method according to  claim 7 , wherein the whiskers are in an amount between 2.5 wt % and 3 wt % of the total weight of the inner cover layer. 
     
     
         9 . The method according to  claim 7 , wherein the whiskers are zinc oxide whiskers. 
     
     
         10 . The method according to  claim 7 , wherein the step of forming the inner cover layer includes:
 mixing the whiskers and one molding resin in a weight ratio of 1:9 to form a first resin composition;   granulating the first resin composition to form masterbatches;   mixing the masterbatches and another molding resin in a weight ratio of 3:7 to form a second resin composition; and   using the second resin composition as a raw material for injection molding.   
     
     
         11 . The method according to  claim 10 , wherein each of the one molding resin and the another molding resin is a highly neutralized acid polymer resin or a metal cation based low acid ionomer resin. 
     
     
         12 . The method according to  claim 7 , wherein the outer cover layer is formed from a metal cation based low acid ionomer resin. 
     
     
         13 . The method according to  claim 7 , wherein the ball core has a coefficient of restitution between 0.65 and 0.85.