| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an aliphatic polyester-based biaxially oriented film capable of obtaining the biaxially oriented film in which processing suitability is excellent in the case of performing printing, laminating and bag making or the like, by raising uniformity of molecular orientation in the inside of the film and to provide a film obtained by this method. SOLUTION: A nonorientated film consists of aliphatic polyester in which a main repeating unit is a formula -O-CHR-CO- (R shows-H or 1-3C alkyl group), as a main component. In the method for producing a biaxially orientated film having a sequential biaxially orientating process in which the nonorientated film is orientated in the longitudinal direction and thereafter orientated in the lateral direction, orientation in the longitudinal direction is performed in a range of temperature not lower than glass transition temperature (Tg)+20 deg.C of aliphatic polyester and not higher than low temperature crystallization temperature (Tc)+20 deg.C and in separation of at least two stages so that the combined draw ratio in the longitudinal direction becomes 2.0-4.5 times. |
