Closure vent arrangement and forming method therefor

Abstract

A venting closure for use with an associated container includes a closure cap having a circular top wall portion and a depending annular skirt portion. The closure is used with a pressurized container having a threaded neck portion defining a land surface at the top thereof. The closure includes a liner therein adjacent and in spaced relation to the top wall, which liner is positioned between the top wall portion and the land surface and defines a pressure release region with the top wall portion. The top wall portion includes an outwardly extending annular bead-like protecting element having a depending inner wall and a contiguous outer wall. The inner wall is oriented generally transverse to a top wall plane. A flexible portion having a piercing element extending inwardly therefrom toward the liner is positioned centrally of the annular protecting bead and is movable so that piercing element contacts and fractures the liner to release pressure from the container. The bead inner depending wall and the outer wall define a vent channel in flow communication with the pressure release region, and the inner wall includes at least one vent opening for providing flow communication to vent the gas from the container toward the center of the closure. A method of forming the venting closure includes providing a mold assembly having a female mold member and cooperating, engageable inner and outer male mold cores and a gate insert, assembling the mold to form a mold cavity, engaging the projections with the at least one landing surface, injecting a plastic material into the mold cavity, forming a plurality of vertically oriented vent openings defining horizontally oriented vent paths in the protective bead depending wall, and disassembling the mold and removing the closure.