| 摘要 |
<p>PURPOSE:To contrive to be able to mold the protecting layer with uniform thickness by a method in which a string rubber wound core covered with a pair of semispherical cup make of thermoplastic film is heated and mold- clamped, and on the protecting layer molded in this manner an outer film resin is injection molded. CONSTITUTION:A pair of semispherical cups 2, 2 covering a string rubber wound core 1 are vacuum-molded with the film made of thermoplastic resin such as, e.g. ionomer resin, etc., and the softening temperature of the cup is 30-100 deg.C and then its thickness is 0.1-1.0mm. The core 1 covered with the cups is received in the mold hole of the pressure mold with a heating faculty, and the mold is clamped at specified temperature and pressure for specified time. Consequently, the resin of the cup is dissolved in the surface-unevenness of the core 1, thereby molding the protecting layer 3 connecting the core 1 to the cups. The core on which the protecting layer has been molded is set in the mold for injection molding, and thermoplastic resin is injected, whereby an outer film is molded. Thus, a golf ballis completed. Thse cup has preferably the softening point in the range of 50-80 deg.C from the consideration for the treatment of the cup and the thermal effect at heating.</p> |
