Patent attributes
A cap 10 which has a female screw 14 in the inner peripheral surface and which is to be screwed on a port neck part 13 of a container main body 11 holding a predetermined liquid, wherein a plurality of ribs 18 radially extending astride from an inner surface of a top surface part 16 of the cap 10 to an inner surface of a peripheral wall part and integrally projecting inwards are formed on a peripheral edge part 17 of the inner surface of the top surface part 16. A female screw 14 is a screw in the form of two threads composed of spiral mated ridges 14a, 14b of two threads, for example. The liquid held in the container main body 11 is, for example, a chlorine-based bleach which contains a surface active agent and a sodium hypochlorite. The mated ridges 14a, 14b each are 80 to 120 degrees in thread angle θ and 1 to 15% of a valley radius of the female screw 14 in thread height H.
