Photochemical frangible closure

摘要

A frangible closure has a closure sheet having a central weakness formed substantially though a medial portion. The central weakness has a thickness and a central portion of greater thickness than the thickness of the central weakness so as to resist shearing of the central weakness. A lateral skirt surrounding the closure has at least a partial radial weakness therebetween for cooperating with the central weakness and enabling the central weakness to fracture.