Golf ball manufacturing method and golf ball

Abstract

The invention provides a method of manufacturing golf balls having covers of very high transparency, which method includes, prior to formation of the cover, a preformed body fabricating step wherein a material that develops a specific color when exposed to ultraviolet radiation is included in or coated onto the preformed body. In this way, a preformed body that matches the cover to be formed can be easily and reliably identified from among a plurality of types of preformed bodies stored at a temporary storage place. The invention also provides golf balls having a construction suitable for carrying out such a manufacturing method. The invention enables golf balls of excellent visibility and stylishness to be efficiently produced.

1 . A method of manufacturing a golf ball having a core, a cover and, optionally, one or more intermediate layer between the core and the cover, the method comprising the steps of:
 fabricating a preformed body which is a core or a sphere comprising a core over which one or more intermediate layer has been formed;   transferring the preformed body to a temporary storage place;   selecting, from among a plurality of preformed bodies stored at the temporary storage place, a preformed body that matches a cover to be formed;   transferring the selected preformed body to a cover-forming step;   forming a cover over the preformed body transferred from the temporary storage place;   in the preformed body fabricating step, including in or coating onto the preformed body a material that develops a color when exposed to ultraviolet radiation (UV chromogenic material); and   in the preformed body selecting step, exposing the preformed bodies stored at the temporary storage place to ultraviolet radiation so as to have the UV chromogenic material develop a color, and identifying by the color a preformed body that matches the cover to be formed.   
     
     
         2 . The golf ball manufacturing method of  claim 1 , wherein the preformed body is selected from the group consisting of:
 cores formed of a composition containing a UV chromogenic material;   spheres obtained by forming one or more intermediate layer over a core, wherein an outermost intermediate layer is formed of a composition containing a UV chromogenic material;   cores coated on all or part of a surface thereof with a composition containing a UV chromogenic material; and   spheres obtained by forming one or more intermediate layer over a core, wherein an outermost intermediate layer has been coated on all or part of a surface thereof with a composition containing a UV chromogenic material.   
     
     
         3 . The golf ball manufacturing method of  claim 1 , wherein the UV chromogenic material is one or more selected from among inorganic phosphors containing an element selected from the group consisting of alkaline earth metals, zinc family elements, transition metals and lanthanide metals; organic phosphors selected from the group consisting of compounds having a fluorene skeleton; and photochromic substances selected from the group consisting of diarylethenes, spiroperimidine, spiropyran and azobenzene. 
     
     
         4 . The golf ball manufacturing method of  claim 3 , wherein photochromic microcapsules are used as the photochromic substance. 
     
     
         5 . A golf ball comprising a core, a cover and, optionally, one or more intermediate layer between the core and the cover, wherein a layer adjacent to an inner side of the cover (layer adjacent to the cover) is formed of a composition containing a material that develops a color when exposed to ultraviolet radiation (UV chromogenic material). 
     
     
         6 . The golf ball of  claim 5 , wherein the layer adjacent to the cover is a core formed of a rubber composition, which rubber composition contains the UV chromogenic material in an amount of from 0.01 to 5 parts by weight per 100 parts by weight of a base rubber. 
     
     
         7 . The golf ball of  claim 5 , wherein the layer adjacent to the cover is an intermediate layer formed of a resin composition, which resin composition contains the UV chromogenic material in an amount of from 0.01 to 5 parts by weight per 100 parts by weight of a base resin. 
     
     
         8 . The golf ball of  claim 5 , wherein the UV chromogenic material is one or more selected from among inorganic phosphors containing an element selected from the group consisting of alkaline earth metals, zinc family elements, transition metals and lanthanide metals; organic phosphors selected from the group consisting of compounds having a fluorene skeleton; and photochromic substances selected from the group consisting of diarylethenes, spiroperimidine, spiropyran and azobenzene. 
     
     
         9 . The golf ball of  claim 8 , wherein the photochromic substance is photochromic microcapsules. 
     
     
         10 . A golf ball comprising a core, a cover and, optionally, one or more intermediate layer between the core and the cover, wherein all or part of a surface of a layer adjacent to an inner side of the cover (layer adjacent to the cover) is coated with a paint containing a UV chromogenic material. 
     
     
         11 . The golf ball of  claim 10 , wherein the paint is a urethane paint. 
     
     
         12 . The golf ball of  claim 10 , wherein the UV chromogenic material is one or more selected from among inorganic phosphors containing an element selected from the group consisting of alkaline earth metals, zinc family elements, transition metals and lanthanide metals; organic phosphors selected from the group consisting of compounds having a fluorene skeleton; and photochromic substances selected from the group consisting of diarylethenes, spiroperimidine, spiropyran and azobenzene. 
     
     
         13 . The golf ball of  claim 12 , wherein the photochromic substance is photochromic microcapsules.