Process for preparation of thermoplastic resin sheets.

摘要

A thermoplastic sheet is prepared by (i) extruding a molten thermoplastic resin in the form of a sheet (10) from a molding die (1); (ii) applying static charges to the extruded resin sheet from a first electrode (3) whereby the charged resin sheet is pinned to the surface of an electrical insulating layer (9) of a quenching roller to quench the resin sheet; (iii) peeling the quenched sheet from the surface of the quenching roller; and (v) applying electrostatic charges having a reverse polarity to that of the electrostatic charges from the first electrode to the exposed surface portion of the quenching roller from a second electrode (4,5). The quenching roller comprises an electrically earthed substrate (8) and the electrical insulating layer (9) formed on the surface of the substrate. The second electrode comprises a plurality of electrodes (4,5) arranged at intervals along the rotating direction of the quenching roller between the sheet-peeling position where the quenched sheet is peeled from the quenching roller and the sheet pinning-initiating position where the sheet to be quenched is pinned to the quenching roller, and the electrical insulating layer has a volume resistance and surface resistance of at least 10<7> OMEGA and a surface roughness not larger than 0.3 mu m expressed as the center line average roughness (Ra).