Inventors:
Frank William Roberts - Midvale UT
Richard Allen Roberts - Salt Lake City UT
Waldo Calvin Roberts - Salt Lake City UT
Robert Howard Blanpied - Centerville UT
International Classification:
B32B 326
Abstract:
A composite panel-board is made up of a rigid, gypsum board, base panel having a rigid, organic plastic, foam layer formed in-situ on, self-adherent to, and essentially covering one of the broad, flat surfaces of the gypsum board base panel. A water-vapor-resistant, flame-retardant layer is adherent to and covers the otherwise exposed, broad surface of the rigid foam layer. The composite panel-board is fabricated by attaching upwardly extending edge sheets on or adjacent to the mutually opposite, side edges of the gypsum board panel so that the mutually opposite edge sheets, together with the gypsum board panel, form a trough. The upper surface of the gypsum board panel is heated to a temperature of at least about 95. degree. F in the presence of a water unsaturated atmosphere, and then a uniform layer of a foamable, liquid, organic plastic material is applied to the upper surface of the gypsum board panel. A sheet of water-vapor-resistant, flame-retardant material is applied to the exposed surface of the layer of liquid, organic plastic material immediately following the formation of such layer on the gypsum board panel, and the foamable, liquid organic plastic material then reacts and expands to form a layer of rigid foam which is self adherent to the gypsum board panel, the sheet of water-vapor-resistant, flame-retardant material, and the edge sheets.