PROCESS FOR PRODUCING POLYESTER FILMS

摘要

A process for producing a polyester film comprises polymerizing a dimethyl-esterified glycol of aromatic dicarboxylic acid with an inorganic particle A of 1-0.67 shape ratio and 0.15-0.45 μm ave. particle dia. and an inorganic particle B of 0.46-0.29 shape ratio and 0.1-0.4 μm ave. particle dia. at the end of an ester exchange reaction, and biaxially drawing the polymer. The polyester film has a good activity, flatness and durability, and is useful as a base film of magnetic recording media.