| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation sinks also in the outside of a screw thread part by forming a groove part along the helical shape of a screw in the center part of the screw thread part. SOLUTION: A female screw part 20 engaged with the male screw of a container main body is formed inside a cap 15. A thick screw thread part 21 and a thin valley part 22 provided between screw thread parts adjacent to each other are helically formed in the female screw part 20, and a groove part 23 is formed along the helical part of the female screw part 20 in the center part of the screw thread part 21. For the resin made cap 15, a material such as polypropylene, polyethylene, ABS or polyacetar is used. Thus, since the thin groove 23 is formed in the center part of the thick screw thread part 21, no sinks occur in the outside of the screw thread part 21. Therefore, a molded article having good appearance and no non-coated parts on a coated surface is provided. |
