Patent attributes
A pressure activated self opening frangible closure seal is bonded over the interior nozzle opening of a pressure operated cartridge container used for storing and dispensing flowable material when pressurized in an application gun. The seal provides a leak proof closure that is strong enough to remain intact during the filling operation of the cartridge, and at the same weak enough to break open and dispense the contents out through the nozzle when a consumer pressurizes the cartridge with the application gun. The seal is constructed from a first layer of leak proof frangible sheet material that is bonded to a second layer of strengthening sheet material. The strengthening layer contains a cut out void configuration that forms a breaking pattern which forces the seal to break open only in the weaker single frangible layered configuration of the cut out void forming the breaking pattern when the cartridge is pressurized.