| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a cellulose acylate film easily with high productivity, which cellulose acylate film has optical properties useful for a retardation film, a polarizing plate or the like and exhibits low Rth in a minus direction. <P>SOLUTION: The method for producing the cellulose acylate film comprises the steps of: casting a cellulose acylate solution on a support and gelling the cast solution; stretching a web stripped off from the support to the direction perpendicular to the conveying direction of the web so that the ratio (W<SB>2</SB>/W<SB>1</SB>) of the width (W<SB>2</SB>) of the stretched web to the width (W<SB>1</SB>) of the unstretched web is 0.8-2; and heat-treating the stretched web at the temperature (T) satisfying Tc≤T<Tm<SB>0</SB>(wherein Tc and Tm<SB>0</SB>are the crystallization temperature and the melting point of the cellulose acylate film before heat-treated, respectively). <P>COPYRIGHT: (C)2009,JPO&INPIT |
