Abstract: The present invention describe a process and an installation for the production of stiff recyclable sandwich-type polymeric panels, preferably polypropylene-based panels, and the panel obtained, comprising three lines, in one of which a polymeric polypropylene-based foamed core is produced by extrusion (line A); the structural skins are produced in a second line (line B), which skins are formed by a polypropylene-based lamina reinforced with wood fiber, on which lamina there is applied an also polypropylene-based surface coating layer reinforced with glass fibers; in the third line the structural skins produced in line B are adhered by heat and pressure to the foamed core produced in line A. The sandwich panel produced has a thickness between 7 and 40 mm, an overall density of 400-700 kg/m3 and an elastic modulus of 5-10 GPa.

Abstract: The present invention describe a process and an installation for the production of stiff recyclable sandwich-type polymeric panels, preferably polypropylene-based panels, and the panel obtained, comprising three lines, in one of which a polymeric polypropylene-based foamed core is produced by extrusion (line A); the structural skins are produced in a second line (line B), which skins are formed by a polypropylene-based lamina reinforced with wood fiber, on which lamina there is applied an also polypropylene-based surface coating layer reinforced with glass fibers; in the third line the structural skins produced in line B are adhered by heat and pressure to the foamed core produced in line A. The sandwich panel produced has a thickness between 7 and 40 mm, an overall density of 400-700 kg/m3 and an elastic modulus of 5-10 GPa.

Abstract: The present invention describes a process and respective installation for continuous production of foamed polymeric sheets by extrusion, another object of the invention being the development and use of polypropylene-based formulations comprising linear polypropylenes and branched polypropylenes. The installation includes four stages: a first stage of extrusion foaming, in which a foaming agent, either of a chemical or physical nature, in the latter case introduced in supercritical conditions, is mixed with the polymeric mass melted previously in the first stages of the extruder, the material expanding exactly at the outlet of the lips of the planar extrusion head; a second stage of calibration and cooling of the foamed sheet, in which the expanded plastic material is cooled by contact in a system of vacuum calibrators and by contact with water in a cooling bath; a stage of collection of the foamed panel; and a final stage of cutting of the foamed sheet, defining the final dimensions thereof.