| 摘要 |
PROBLEM TO BE SOLVED: To provide a cap which can effectively prevent damages of the cap caused by the environmental stress breakage without increasing the wall thickness of the cap. SOLUTION: This cap 10 bas an internal screw 14 on an inner circumferential surface thereof to be screwed in a neck part 13 of a container body 11 holding a predetermined liquid accommodated therein, and the internal screw 14 comprises two to four threads comprising two to four spiral projecting bars 14a and 14b to be screwed. The liquid accommodated in the container body is a surfactant and a chlorine-based bleaching agent for instance containing sodium hypochlorite. The screw angle θ of the projecting bars 14a and 14b to be screwed is 80-120 deg., and the screw height H is 1-15% of the thread bottom radius of the internal screw 14. |
