Abstract: A product for heating a load at different rates using microwave radiation provided at a substantially constant power level. The product may include a polymer matrix alone or in combination with a metal substrate, with the polymer matrix located on the surface of the metal substrate that does not contact the load and is thus disposed to the incident microwave radiation. The matrix includes dielectric and magnetic components in amounts that enable at least initial absorption of the incident radiation and thus initial thermalization of the radiation within the matrix. The matrix is designed to change its rate of thermalization and the rate at which it conducts thermalized radiation to the substrate and load after a predetermined time of exposure to the radiation at a predetermined temperature of the matrix.

Abstract: Means and method for heating loads with microwave energy, with the loads being located on a metal substrate or in a metal container. A layer of organic material is located on the outside surface of the container or substrate, the layer having microwave absorbing substances contained in a minimum thickness of the layer. The absorbing substances include both dielectric and magnetic components that provide useful power absorption, the amount of the dielectric component being effective to compress the wavelength of the microwave energy while simultaneously preserving useful impedance to the magnetic component of the energy. Useful power absorption within a range of minimum layer of thicknesses is obtained. The amounts of the dielectric and magnetic components, in addition, transport the heat generated within the layer to the metal container or substrate at rates sufficient to maintain internal temperature of the layer near that of the load.

Abstract: An improved metal foil composite sheet and method of fabricating the same for heating and/or cooling food products. Metal foil is coated on one surface with a heat stable, thermoplastic, epoxy and on its second surface with a heat resistant, dielectric, thermosetting base coat and a top coat of a heat resistant, heat absorptive, thermosetting material. The top coat may be applied in zones of distinct thicknesses simultaneously. Such application provides for legible printing, while preserving the desired heat absorptive properties on the entire foil pouch stock including both the printed and unprinted regions. A completed foil pouch composed of the foil composite sheet permits uniform heating and/or cooling of foods over an extended range of temperatures and times while resisting undesired deterioration.