| 摘要 |
PROBLEM TO BE SOLVED: To provide a plastic cap with an outer seal ring wherein tightening torque at putting on a bottle is not large, opening torque at removing the cap is not large, and sealability is good. SOLUTION: The plastic cap comprises a thread part to be screwed with a thread part of a bottle neck on an inner peripheral surface of a peripheral wall, wherein the cap is to be crewed with the bottle neck to be mounted. The outer seal ring 130 in close contact with an outer peripheral surface above the thread part 211 of the bottle neck 210 is provided to protrude approximately horizontally toward the center on an upper part of the thread part 121 of the inner peripheral surface of the peripheral wall 120. |
