| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an easy-to-open synthetic resin-made cap which hardly causes slippage at fingers when being opened has excellent openability for easily opening the cap without any sense of incongruity or pain for the fingers, and manufactured at a low cost without changing the structure of a conventional synthetic resin-made screw cap. <P>SOLUTION: In the synthetic resin-made cap with a knurl formed at an outer peripheral part of a cylindrical wall hanging from a top wall, extremely fine irregularities 15 are formed on the entire surface or a part of the surface of the knurl 4. The extremely fine irregularities distributively exist so that the irregularities of ≥10 μm are present at a rate of 11-40 pieces/10 mm from a reference line of surface roughness. The extremely fine irregularities are formed on a die by the transfer of the extremely fine irregularities formed by etching on a cavity surface. <P>COPYRIGHT: (C)2009,JPO&INPIT |
