Manufacturing method of biaxially stretched polyester film as base film for photographic film

摘要

The present invention comprises the steps of passing a molten aromatic polyester containing naphthalene-2,6-dicarboxylic acid as the main dicarboxylic acid component and ethylene glycol as the main glycol component through a single or multilayer metal fiber nonwoven fabric; Melt extruding the molten polymer in the form of a sheet; Quenching and solidifying the sheet to yield a non-stretched film; Biaxially stretching the non-stretched film; And thermally curing the biaxially stretched film to form a biaxially stretched polyester film as a base film for a photographic film, which hardly contains a large gel of 40 µm or more. It is about.