FORMING THERMOPLASTIC WEB MATERIALS

摘要

A web of thermoplastic material extruded directly into a set of tempering rolls is cooled on its upper and lower surfaces while the interior of the web is kept molten. The partially cooled web is fed onto a conveyor on which it is fed to a thermoformer. The web remains on the conveyor until its surface layer in contact with the conveyor is reheated to a thermoformable temperature below that at which the web will stick to the conveyor. Apparatus for feeding a web of thermoplastic material from an extrusion to a thermoformer includes tempering rolls and conveyor means which can be adjusted in their relative positions and to control the length of conveyor means contacted by the web.