FILTERING APPARATUS AND METHOD FOR POLYESTER, AND METHOD FOR MANUFACTURING POLYESTER FILM

摘要

PROBLEM TO BE SOLVED: To provide a filtering apparatus for a polyester suppressing the pyrolysis of the polyester at the time of filtering, and to provide a method for enhancing the productivity of a polyester stretched film. SOLUTION: A large number of leaf disk filters are housed in casing laminated with multi-layer. A molten polyester flows through the space between the inner surface of the casing and the leaf disk filters, and is filtered through the leaf disk filters. In this filtering apparatus, the flow resistance of the leaf disk filters to the molten polyester is 1.3 times or less the average of the flow resistance of the housed leaf disk filters.