Abstract: A bag for popping popcorn in a microwave oven has substantially rectangular front and back walls and gusseted side walls joining the opposite side edges of the front and back walls. The gusseted side walls each has a medial gusset fold, defining a pair of gusset panels joined along longitudinal folds to the adjacent side edges of the respective front and back walls. When the bag is folded flat, the gusset panels and medial gusset folds lie between the front and back walls, with the medial gusset folds of the opposite gusseted side walls normally spaced from one another. Transverse bands of adhesive extend across the top and bottom ends of the bag interior surface to adhesively attach the gusset panels to the respective front and back walls, forming bag end closures.

Abstract: A multi-ply laminated wall structure, especially for a bag for popping popcorn in a microwave oven, has at least two plies of paper secured together with spaced patches of adhesive to form a unitary laminated structure that has greater flexibility and lower cost than a conventional bag wall. The adhesive covers from about 25% up to about 60% of the confronting area between the plies, and the unsecured areas between the patches of adhesive are in communication with one another. The outer ply is gas permeable so that gas is permitted to escape from between the plies, and any moisture between the plies escapes through the unsecured areas between the patches of adhesive at the ends of the laminated structure.