Abstract: An extrusion system includes a main extruder and a secondary injection extruder. Both extruders are connected via a three-way valve. The main extruder has a mixing section downstream of the junction point with the secondary injection extruder. An accelerated switch between molding masses with different colors can be made by switching the three way valve.

Abstract: A process for the extrusion of plastic plates with very finely structured surface using an extrusion system which is equipped with an extruder and a three roll polishing stack containing a roller with the structuring surface. The system is designed for coextrusion and the plastic plates are produced via two extruders as a coextrudate CX from a highly viscous basic molding compound BF and a low viscosity molding compound NF which is extruded on BF. The surface of said plates is structured via the three roll polishing stack. Fresnel lenses produced by the process may be used in solar collectors.

Abstract: A process for the extrusion of plastic plates with very finely structured surface using an extrusion system which is equipped with an extruder and a three roll polishing stack containing a roller with the structuring surface. The system is designed for coextrusion and the plastic plates are produced via two extruders as a coextrudate CX from a highly viscous basic molding compound BF and a low viscosity molding compound NF which is extruded on BF. The surface of said plates is structured via the three roll polishing stack. Fresnel lenses produced by the process may be used in solar collectors.

Abstract: The height of the bulge in the glazing roll gap of a supercalender in the extrusion of plates or films of a thermoplastic material smoothed on both sides may be controlled by measuring the location of the edges of the plastic sheet by means of measuring sensors and regulating the speed of the roll or the rate of extrusion of the polymer melt based on the width of the sheet so that the height of the bulge is always kept within tight tolerances.

Abstract: The invention provides a thermoplastic multilayer composite comprising at least one layer of polyamide and at least one layer of polyalkyl (meth)acrylate, bonded via at least one coupling agent interdisposed between the layers such that they adhere to one another. The composites obtained have excellent resistance to chemicals and solvents.

Abstract: A plastic film is formed by passing a web of extruded thermoplastic material through a slit formed between a pair of smoothing rolls. One of the rolls is biased toward the other roll by a yieldable biasing mechanism to accommodate variations in thickness of the web.

Abstract: The invention relates to transparent composite plate systems of a) at least two acrylic glass exterior plates S, S' with a thickness of at least 2 mm and parallel surfaces, and b) an intermediate layer Z containing a thermoplastically processable elastomer E, whereby the elastomer E contains from 60-100% by weight of a comb polymer KP, which itself contains from 50 to 5% by weight of at least one polymethyl methacrylate macromonomer of Formula I ##STR1## and from 95 to 50% by weight of alkyl acrylates of Formula II ##STR2## wherein R and R.sub.4 are defined in the claims.