| 摘要 |
PURPOSE:To ensure the sealability and appearance quality of a neck part top face by discontinuously providing peripheral grooves formed along a circumferential direction in a neck outer peripheral wall between the top face and a locking stage of a bottle neck part. CONSTITUTION:In order to form a locking stage 36 for engaging a ring-like locked part 16 of a cap 10, a large diameter part 32 on a side of an opening end must be considerably thicker than a small diameter part 34 at its lower end. However providing a peripheral groove 40 in the thick large diameter part 32 in its circumferential direction can realize thinning. The thinned region formed over a considerably large range in the peripheral direction can effectively prevent a sink mark from being occurring at a neck top face 30 where a resin material is finally placed. In addition since the peripheral groove 40 is discontinuous in the circumferential direction, a rib 42 can be formed at a desired position in the circumferential direction, the rib 42 can regulate a ring- like locked part 16 entering the peripheral groove 40 and a snap-on type cap 10 can be smoothly mounted. |
