Abstract: A vacuum thermoforming process for producing a transparent molding free from optical defects, whereby the prior temperature of the mold and preform is controlled, the preform is premolded, the mold is shaped under sub-atmospheric pressure, the mold shape is cooled, and the transparent molding is removed. The transparent plastic molding is produced from polymethyl methacrylate (PMMA) or polycarbonate (PC) with particularly good optical quality and with relatively low cycle times. Upon removal, these moldings are dimensionally stable, free from distortion, and exhibit no surface defects such as pimples.

Abstract: Flat composites of plastic are manufactured by thermal adhesive bonding of at least two plastic parts which are heated at their surfaces and which comprise a base material coated with a plastic layer, wherein the Vicat softening point of the plastic of layer is 5 to 40° C. lower than that of the base material, wherein the base material has a thickness of 1 to 200 mm and the plastic layer has a thickness of 5 to 400 ?m, and each of the parts is heated on the surfaces coated with the plastic layer and then welded under pressure.

Abstract: Flat composites of plastic are manufactured by thermal adhesive bonding of at least two plastic parts which are heated at their surfaces and which comprise a base material coated with a plastic layer, wherein the Vicat softening point of the plastic of layer is 5 to 40° C. lower than that of the base material, wherein the base material has a thickness of 1 to 200 mm and the plastic layer has a thickness of 5 to 400 &mgr;m, and each of the parts is heated on the surfaces coated with the plastic layer and then welded under pressure.

Abstract: Flat composites of plastic are manufactured by thermal adhesive bonding of at least two plastic parts which are heated at their surfaces and which comprise a base material coated with a plastic layer, wherein the Vicat softening point of the plastic of layer is 5 to 40° C. lower than that of the base material, wherein the base material has a thickness of 1 to 200 mm and the plastic layer has a thickness of 5 to 400 &mgr;m, and each of the parts is heated on the surfaces coated with the plastic layer and then welded under pressure.

Abstract: The invention relates to a method for the production of flat laminates (5) from polymethacrylate plastic, by thermal adhesion of at least two parts (1) of polymethacrylate plastic heated at their surface, with the characterizing features that the parts (1) of polymethacrylate plastic, which have been preheated to surface temperatures of 130.degree. to 200.degree. C. on the adhesion side (1a), and which maintain their original shape during the preheating phase, are pressed together between a pair of rollers (2, 3), of which at least one roller (2), by means of which the pressure force (4) is exerted, is mounted in movable manner, at a feed velocity being between 5 and 200 mm/s and a pressure force acting on the roller (3) between 10 and 500 N.