Patent ID: 7993562

Claim:
A method for producing a thermoplastic film, comprising cooling and solidifying a filmy thermoplastic resin melt extruded out through a die, by holding it between a metallic presser and a metallic casting roll for cooling; wherein the temperature of the filmy thermoplastic resin just before being held between the metallic presser and the casting roll for cooling is from Tg+20° C. to Tg+90° C., in which Tg is a glass transition temperature of the thermoplastic resin, and a difference between a surface temperature (Tt) of the metallic presser and a surface temperature (T1) of the casting roll for cooling satisfies the following formula (1), and a contact length Q, which is a length contacting one surface of the filmy thermoplastic resin with the metallic presser and contacting the other surface of the filmy thermoplastic resin with the casting roll for cooling, satisfies the following formula (2): 0.5° C.≦ T 1 −Tt≦ 20° C. (1) 0.1 cm≦Q≦8 cm (2) wherein T1 indicates a surface temperature of the casting roll for cooling; Tt indicates a surface temperature of the metallic presser; Q indicates a contact length, which is a length contacting one surface of the filmy thermoplastic resin with the metallic presser and contacting the other surface of the filmy thermoplastic resin with the casting roll for cooling.