Foam rigidizing process and products produced therewith

A composite, rigid, structural, foam panel (11) comprising: (i) a flexible, non-structural, open cell reticulated or semi-reticulated, foam sheet (10); and (ii), an essentially closed cell resinous foam formed from a flowable, foamable material (12); and, wherein the open cell non-structural foam sheet (10) and the essentially closed cell foam are each coextensive with the volume of spaced defined by the panel (11). In a preferred embodiment of the invention, the flexible, non-structural, open cell reticulated or semi-reticulated foam sheet (10) comprises an electromagnetic wave absorber and, consequently, the essentially closed cell rigid structural panel (11) produced comprises a rigid, structural electromagnetic wave absorber. The rigid panels and/or absorbers (11) of the present invention are preferably formed of urethane-like materials and in a process embodying the invention wherein: a flowable, foamable, resinous material (12) composed of Components "A" and "B" and a suitable cream are proportioned to form a panel (11) of the desired shape; the Components are thoroughly stirred, and introduced into the bottom of a preheated, vented mold (15) having suitable vents (19); the open cell flexible foam sheet (10), precut to the desired size, is inserted into the mold (15) on top of the flowable, foamable, resinous material (12); the lid (18) of the mold (15) is closed and clamped in place; and, the reactive Components "A" and "B" are allowed to foam and expand in an exothermic reaction, whereby the expanding material (12) is forced into, entirely through, and entirely throughout the open cell foam sheet (10) with excess material (12) escaping from the mold (15) through the vents (19). After curing at room temperature for at least two hours, the panel (11) is demolded and trimmed as required.