METHOD FOR PRODUCING FILM WITH POLYMER SOLUTION TO DRY FILM BY PLURAL DRYING PORTIONS ARRANGED TOWARD ADVANCING DIRECTION OF FILM NEAR FILM

摘要

PURPOSE: A film production method from polymer solution is provided to effectively dry a cast dope without damaging an optical characteristic and a thickness of a film. CONSTITUTION: A dope(11) contains a cellulose acylate as a main component of a polymer. The dope is casted on a carrying belt(31). A first and a second drying portions are arranged in a moving direction of the belt near a gel typed film on the belt. A temperature difference between dried air and discharged air from the first drying portion is higher than the second drying portion. The discharged air of the first drying portion is heated by a heat exchanger to reduce the content of solution for using as dried air of the second drying portion. The produced film has the excellent thickness uniformity and is sufficient as an optical polymer film.