| 摘要 |
PROBLEM TO BE SOLVED: To obtain, at a high speed, a thermoplastic resin sheet with both excellent productivity and quality by using a freely rotating roll as an electrified roll in a method for preparing the thermoplastic resin sheet wherein after a thermoplastic resin is melted, a molten sheet is extruded from a nozzle and it is cooled and solidified while it is placed between the electrified roll and a cooling medium. SOLUTION: A molten thermoplastic resin sheet is cast while it is placed between a freely rotating electrified roll and a cooling medium. It is possible thereby to provide a large electric charge density (an electric current) by a relatively low electric voltage to the molten resin sheet as the electric charge is directly provided to the sheet without placing air. Therefore, it is brought into strongly intimate contact with the cooling medium to improve high speed adhesive properties and uniformity of thickness. In this case, as the thermoplastic resin, especially polyester resins and polyamide resins are pref. In addition, electrostatic charging effectively acts in a case where resistivity during the resin is melted is large, at least 108Ωcm. In addition, thickness fluctuation is generated on the resin sheet when rotational torque of the electrified roll is 300 g or larger.
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