Abstract: Blow molding and thermoforming processes in which a mold system having low thermal inertia mold-halves provided with heating and cooling systems is utilized for producing plastic articles coated with surface-upgrading films of high melting polymers or polymers exhibiting a high scratch resistance to improve mechanical characteristics of the molded article. The films may be positioned, before the mold is closed, close to the low thermal inertia mold-halves. Rapid heating and rapid cooling of the mold-halves in contact with the surface-upgraded films permit strength adhesion of the upgrading material to the surface of the molded article.

Abstract: A self-supporting roof plate for motor vehicles and the like is disclosed, characterized in that said roof plate consists essentially of a composite structure comprising a plate of rigid thermoplastic material bonded to a layer of foamed plastic material having a thermo-acoustical insulating function, and a layer of an aesthetically pleasing plastic material, said multi-layer structure being so shaped as to include on opposite sides two hook-like or S-shaped arcuate strips forming elastically yielding strips, adapted for the assemblage of the structure against the roof body of the car, by snap-fitting said arcuate strips into grooves prearranged between the roof ceiling and the body sides of the vehicle. The rigid plate may be a box-type or similar structure. The arcuate strips may be obtained by the thermo-forming of the composite structure.