SYNTHETIC RESIN CAP, CLOSURE DEVICE, BEVERAGE-CONTAINING CLOSURE DEVICE AND PROCESS FOR PRODUCING SYNTHETIC RESIN CAP

摘要

Synthetic resin cap (1) having top plate part (2) and tubular part (3) suspending from the rim thereof, the tubular part (3) provided with cleaning water introduction aperture (17), the top plate part (2) provided on its superior surface with printing (15), characterized in that among tubular part external surface (3a) of an area including the peripheral portion around at least one cleaning water introduction aperture (17) and the superior surface (2b) of the top plate part, only the superior surface (2b) of the top plate part is surface treated so as to enhance the wettability thereof. As only the superior surface (2b) of the top plate part is surface treated so as to enhance the wettability thereof, there can be facilitated inflow of cleaning water fed to the external surface (3a) of the synthetic resin cap (1) through the cleaning water introduction aperture (17) into the interior of the synthetic resin cap (1).