Method and apparatus for producing microwave susceptor sheet material

Claim 1

A paperboard type microwave susceptor sheet material formed by a laminating process for use in a disposable food appliance package adapted to heat a surface of food associated with said food appliance package when said food appliance package is exposed to microwave energy, said susceptor sheet material comprising: (a) a microwave interactive layer of electrically conductive metal having a thickness which causes said microwave interactive layer to be heated when subjected to microwave energy, said microwave interactive layer heats said surface of said food in heat transfer relationship therewith; (b) protective means for said microwave interactive layer, said protective means including smooth surfaced thin plastic film with an extruded thickness of less than or equal to 1.0 mil so that at high temperature it will remain stable and not degrade when the susceptor sheet material is subjected to microwave energy to heat said surface of said food, said plastic film being PCTA copolyester with a melting point of over 500° F.; and, (c) support means for providing structural support for said interactive layer and said plastic film, said support means being formed of thin paper stock material having structural stability while heating said surface of said food to maintain its physical shape; wherein said susceptor sheet material is formed by said laminating process including the steps of vacuum depositing said microwave interactive layer onto smooth surfaced thin plastic film followed by bonding directly said thin plastic film upon which said microwave interactive layer has been vacuum deposited to one side of said paper stock material in a manner to cause said thin plastic film and said microwave interactive layer to be held in bonded relationship with said support means.