| 摘要 |
PROBLEM TO BE SOLVED: To provide container lids (2, 102) for positively sealing port necks (50, 150) of the container, being removed from the port necks without requiring any excessive torque and causing the port necks to be opened after the lids are rotated by not less than a requisite angle of rotation and further to provide such a container lid showing no problem of generating inconvenience in a printing step irrespective of the fact that a requisite time for the molding operation can be substantially reduced. SOLUTION: Outer cylindrical seal pieces (32, 132) and inner cylindrical seal pieces (34, 134) having predetermined shapes and set at their predetermined sizes and annular seal protrusions (36, 136) arranged between these seal pieces are installed at the inner surfaces of top surface walls (4, 104) of a container lid. The wall thickness of the central segment (42) of the top surface wall is reduced to a predetermined range and a plurality of ribs (48) of predetermined thickness are formed at the inner surface of the top surface wall. |
