abstract |
A heating unit comprises a substrate having a first surface and a second surface. A chemical reactant material capable of undergoing an exothermic reaction is disposed on at least a portion of the first surface of the substrate. An igniter is in proximity with the chemical reactant material. A layer of adhesive material overlays at least a portion of at least one of the chemical reactant material and the first surface of the substrate. Other embodiments of the heating unit include a first and a second substrate, each having first and second surfaces positioned with the first surfaces opposing each other in a sandwich construction. A chemical reactant material is disposed on at least a portion of the first surface of at least one of the substrates. The first and the second substrates are sealed together to define a cavity containing the chemical reactant material and an igniter is provided in proximity with the chemical reactant material. |