Process for the sizing of coextruded, multiple-layer extruded profiles from thermoplastic synthetic resins

摘要

A process for sizing an extruded thermoplastic structure or member formed by coextrusion of a core profile of one thermoplastic material and a cover layer of another thermoplastic material provided over a portion of the periphery of the core profile which includes the steps of sizing the extruded plastic structure in the external cross sectional dimensions, cooling during the sizing step the structure and effecting a different temperature control of the cooling of the cross section of the profile depending upon the thermoplastic material being cooled. The thermoplastic material having the higher Vicat softening temperature being more gradually cooled than the one having a lower Vicat softening temperature.