| abstract |
PROBLEM TO BE SOLVED To provide a method for producing a film excellent in quality, productivity and optical isotropy, and an acrylic film using the same. A method for producing an acrylic film, comprising steps (1) to (4) and substantially obtained within 30 minutes after casting a film having a thickness of 20 to 80 μm. (1) An organic solvent solution of an acrylic polymer is cast on a substrate and dried until it exhibits self-supporting properties. (2) The acrylic polymer self-supporting film is peeled off from the substrate. (3) Using a method of gripping both ends of the self-supporting film with a tenter or a method of reinforcing by sticking a heat-resistant tape to both ends of the self-supporting film, the glass transition temperature of the acrylic polymer is Tg (° C), the heat treatment temperature Is T 1 (° C.) and the heat treatment time is θ 1 (seconds), and heat treatment is performed under the conditions satisfying the formulas (A) to (B). (4) When the stretching temperature is T 2 (° C.), the stretching time is θ 2 (seconds), and the stretching ratio is E 2 (times), stretching is performed under the conditions satisfying the formulas (D) to (H). [Selection figure] None |