Patent ID: 7019271

Claim:
An insulating microwave packaging material comprising: a first substantially vapor impermeable substrate; a layer of microwave interactive material supported by the first substantially vapor impermeable substrate; a dimensionally stable substrate bonded to the layer of microwave interactive material; and a second substantially vapor impermeable substrate bonded to the dimensionally stable substrate, wherein the second substantially vapor impermeable substrate and the dimensionally stable substrate are bonded along bond lines formed in a pattern; the bond lines are substantially vapor impermeable; and the pattern defines a plurality of closed cells bounded by the second substantially vapor impermeable substrate, the dimensionally stable substrate, and the bond lines; wherein, upon impingement of the insulating microwave packaging material by microwave energy in a microwave oven, each of the plurality of closed cells expands to form an insulating pocket comprising; a bulging side; and an opposing side; wherein the bulging side comprises a portion of each of the first substantially vapor impermeable substrate, the microwave interactive material layer, and the dimensionally stable substrate; the opposing side comprises a portion of the second substantially vapor impermeable substrate; and the bulging side lofts away from the opposing side.