| 摘要 |
PURPOSE:To well part a golf ball from the metallic mold and to allow molding with high accuracy by forming a chromium oxide film on the surface of the cavity of the metallic mold body for molding the golf ball and coating the film surface with a fluororesin. CONSTITUTION:The chromium oxide film 2 is formed on the surface of the cavity of the metallic mold body 1 formed of iron, copper alloy, etc., by an electrocasting method, high precision method, etc. The film 2 can be formed by black chrome plating, electrochromating, etc. The film 2 surface is then coated with the fluororesin to form a mold parting film 4 consisting of the chromium oxide film 2 and the fluororesin coating layer 3. The fluororesin is adequately tetrafluoroethylene/hexafluoropropylene copolymer, polytetrafluoroethylene, etc. The film 2 surface is coated with the powder or dispersion of the fluororesin, by which the adhesion by baking is improved. The good mold parting property is imparted to the metallic mold in this way and the deterioration in accuracy, sphericity, etc., is obviated. |
