Method of co-extrusion with foam core

摘要

This invention relates to a method for the manufacture of plastic sandwich element in which a first extruder is charged with essential ingredients for productions of foamed cellular plastic at a predetermined temperature. A second extruder is charged with essential ingredients for production of solid plastic at a temperature of at least 25 degrees farenheit from the predetermined temperature. The resulting sandwich is extruded through an extrusion die forming an integral plastic sandwich with the solid plastic layer controlling to a desired extent further foaming of the cellular plastic.