Patent ID: 7244223

Claim:
A method of making a plurality of flexible containers, comprising the steps of: manufacturing a plurality of bag structures, each bag structure having a panel with an opening therein; separately manufacturing a plurality of valves, each valve comprising a vent layer which is pervious with respect to expected gasses and a sealable area; aligning each of the valves with an opening in a bag structure so that the sealable area forms a sealed passageway between the vent layer and the bag structure; and securing the aligned valves to the bag structures; wherein the valve manufacturing step comprises the steps of: providing a vent material which is pervious with respect to expected gasses; positioning an adhesive on an inner surface of the vent material in a pattern corresponding to the sealable areas; cutting the vent material into shapes corresponding to the shape of the vent layer; providing a cover material which is impervious with respect to the expected gasses; positioning a vent-to-cover adhesive between the outer surface of the vent material and the inner surface of the cover material; and overlaying the vent material and the cover material so that the outer surface of the vent material is adjacent an inner surface of the cover material and secured thereto by the adhesive; wherein the cover material is also cut during said cutting step and the valves also each include a cover layer and an area between the vent layer and the cover layer defined by the vent-to-cover adhesive.