Thermoplastic resin film and method for producing the same
AssigneeFUJIFILM Corporation
InventorShinichi Nakai
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Abstract
A method for treating an unstretched thermoplastic resin film. The method includes includes heat treating an unstretched thermoplastic resin film at a glass transition temperature of the thermoplastic resin Tg° C. or higher and Tg+50° C. or lower for 10 seconds or longer and 600 seconds or shorter while conveying the thermoplastic resin film at a tension of 2 N/cm2 or higher and 50 N/cm2 or lower. The method provides a thermoplastic resin film has an in-plane retardation (Re) and a retardation in the thickness direction (Rth) close to 0 nm, and as such the thermoplastic resin film after heat treatment has |Re| of 0 to 10 nm and |Rth| of 0 to 20 nm.
Claims13
A method for producing a thermoplastic resin film, comprising a step of:
- heat treating an unstretched thermoplastic resin film not having undergone stretching treatment in a stretching step, at a glass transition temperature of the thermoplastic resin Tg° C. or higher and (Tg+50)° C. or lower for 10 seconds or longer and 600 seconds or shorter while conveying the thermoplastic resin film at a low tension of 2 N/cm2 or higher and 50 N/cm2 or lower,
- whereby an occurrence of an in-plane retardation (Re) and a retardation in the thickness direction (Rth) in the thermoplastic resin film is prevented by this step, and the thermoplastic resin film after the heat treatment has |Re| of 0 to 10 nm and |Rth| of 0 to 20 nm.
Dependencies are inferred from the claim text.