A METHOD FOR THE MANUFACTURE OF THERMOPLASTIC RESIN SHEETS

摘要

Thermoplastic resin sheets are manufactured by extruding molten thermoplastic resin at an extrusion velocity V through a slit provided in an extrusion mold so as to form thermoplastic resin sheets with embossed surfaces, the thermoplastic resin being extruded from the slit in said extrusion mold under conditions such that the ratio V/H of said extrusion velocity V to the width H of said slit exceeds a critical value (V/H)c, which is the ratio of the extrusion velocity to the width of the mold slit corresponding to the minimum value of the roughness of the embossment formed on the surface of said thermoplastic resin sheets, whereby defects such as the adhesion to and winding on to rollers, inferior appearance and sizing marks which are prone to occur when the sheets are embossed with embossing rollers may be eliminated.