Abstract: An extruded hollow thermoplastic board, which includes a pair of flat and parallel sheets spaced apart and interconnected by extending ribs, generally has a plurality of depression bands in the areas where the flat sheets and extending ribs are joined. The bands, which negatively affect the surface flatness, are especially apparent for crystalline thermoplastic materials. A hollow thermoplastic board, which effectively reduces the depth of the depression bands by inclusion of locationally fixed gas pockets in the rib area during production, is disclosed in the present invention. The hollow thermoplastic board of the present invention substantially enhances the surface smoothness and is highly beneficial to applications such as printing, lamination and graphic art. The present invention also provides a method for production of the hollow thermoplastic boards of smooth surfaces.

Abstract: Methods are provided in this invention to produce wood-like boards of polyvinylchloride, which are suitable for applications, such as graphic art, construction, furniture, etc. In one of the two embodiments disclosed in this invention, the wood-like polyvinyl chloride boards have smooth surface quality, a density below 0.95 g/cm3, good dimensional stability and strong abrasive resistance. These are produced by hot mixing, cold mixing, extrusion, calibration for quenching and subsequent cutting, to produce solid skin, foamed core products. In the other embodiment, the wood-like polyvinyl chloride boards have embossed surface quality, a density below 1.0 g/cm3, good dimensional stability and surface hardness. These are produced by hot mixing, cold mixing, extrusion and subsequent slow cooling with a roller system to produce embossed products.

Abstract: A device and method for selectively removing one or more components from a multicomponent gas/vapor mixture by membrane fractionation. The membrane fractionation gas removal system preferably comprises: a feed chamber which contains the gas/vapor mixture; at least one porous membrane having a first side which contacts the gas/vapor mixture in the feed chamber, and a second side; at least one nonporous membrane having a first side which contacts the second side of the at least one porous membrane, and a second side, the nonporous membrane having a permeability selective to one or more components; an exit chamber connected to the second side of the at least one nonporous membrane such that the component exiting the nonporous gas enters the exit chamber; and an evacuation member connected to the exit chamber for evacuating one or more components from within the exit chamber.

Abstract: An extruded hollow plastic board is described which has a pair of flat and parallel sheets spaced apart and interconnected by longitudinally extending ribs. The ribs and sheets are connected with rounded joint areas, which significantly improve the mechanical properties and solve undercut and die line problems existing with prior art hollow plastic boards. This invention also provides a method for the manufacture of the hollow board of thermoplastic resin thereof.