Single-pleated microwave popcorn package

Claim 1

A backage formed from a length of microwave energy transparent sheet material, said sheet material forming said package having longitudinally extending opposed marginal edges, said package comprising two substantially planar opposed faces of said sheet material defining a product-containing chamber and a heat-expandable food product therein; two opposed longitudinally extending fold lines in said sheet material joining the longitudinal periphery of said opposed faces; a longitudinally-extending seam intermediate said fold lines, integral with and projecting away from said one of said face, outside the plans of said one face, said seam comprising a seal between said opposed marginal edges such that said edges are sealed to each other in face to face congruent fashion; and a longitudinally-extending pleat intermediate said fold lines, integral with and projecting away from said face opposite said one of said faces, outside the plane of said opposite face, said pleat comprising an additional fold line in said sheet material and additional opposed faces and foldable to lie against said opposite face, said package further comprising two opposed transverse seals extending substantially along only the transverse edges of said package to seal the product contained therein, said transverse seals sealing said opposed faces to each other along said transverse edge and sealing said additional opposed faces to each other that constitute said pleat, said sheet material being otherwise unsealed between said opposed faces and said additional opposed faces and the orientation and configuration of said pleat and said transverse seals being such that when said package is placed in a microwave oven with said pleat folded against said opposite face adjacent the oven floor and microwave energy applied to the package, the expandable product will cause the expansion of said pleat creating a three-surface, generally tubular structure with sealed transverse edges each surface having one common edge with each of the other surfaces and each surface convexly curved around between the sealed transverse edges and between its common edges such that only one of said surfaces of the package contacts said oven floor and makes minimal contact between the package and the microwave oven floor thereby reducing heat transfer from said package to said floor, at least one of said sealed transverse edges being peelable after microwave heating so that said package is openable by grasping said pleat and said seam and pulling in opposite directions so that the package opens along said peelable transverse seal.