US Patent 11180288 Synthetic resin container lid

A container lid (2) can be removed from a mouth-neck section (106) of a container without the need for a tool. Following the breakage of a breakable thin-walled line (70) in a transition region (52), the breakage of a breakable thin-walled connection wall (68) in a side wall separation region (54) can be started sufficiently smoothly in the container lid (2). For this purpose, the breakable thin-walled line (70) formed in a side wall (10) in the transition region (52) is brought into a form in which at least a part thereof extends obliquely downwardly in a counterclockwise direction.