Patent ID: 7055713

Claim:
An easy-opening closure for hermetic sealing of an open end of a retortable container, the closure comprising: a metal end ring having a deformable outside peripheral area adapted to be joined to the open end of the retortable container, an intermediate area extending radially inward from said outside peripheral area and defining an opening to allow access therethrough to the interior of the container, and a folded area folded into the interior of the container and extending radially outward from said opening and substantially parallel to and in abutting contact with said intermediate area and so as to terminate in a metal end edge; a first membrane patch having an outside peripheral area overlapping and attached to an under side of said intermediate area of said metal end ring at a portion of the intermediate area which does not overlie the folded area by a bond having predetermined shear and tensile force strengths, and being also bonded to the folded area such as to seal the metal end edge, and having an inside peripheral area extending inwardly into said opening; and a second membrane patch of sufficient size to cover said opening and having an outer peripheral area overlapping and attached to an upper side of said first membrane patch by a bond having predetermined shear and tensile force strengths; wherein said predetermined shear and tensile force strengths of said bonds are sufficient to withstand shear and tensile forces created during retort processing of the container, while allowing easy-opening of the container by peeling said second membrane patch, and wherein said first membrane patch prevents contamination of contents of the container by said metal end edge.