| 摘要 |
PROBLEM TO BE SOLVED: To provide a plastic cap which is easily opened, is excellent in grip performance of a tool, and can reliably perform fitting to a mouth of a container by screw engagement.SOLUTION: According to the present invention, in a plastic cap which is provided with a top plate part and a skirt falling from a peripheral end edge of the top plate part, in which on an outer surface of the skirt, a knurl formed by repetition of mountains extending in an axial direction is provided all around, the knurl is composed of an upper region where a ridge line of the mountain and a valley line on a boundary of the adjacent mountain extend in parallel with each other and a lower region where an inclination angle of the ridge line and an inclination angle of the valley line with respect to an axial direction line differ. The lower region includes a valley line smaller in inclination angle than an inclination angle of the ridge line, and in all areas including the upper region and the lower region, the inclination angles of the ridge lines are fixed.SELECTED DRAWING: Figure 3 |
