| 摘要 |
PURPOSE:To produce the titled polyester low in content of coarse particles, by adding an ethylene glycol slurry containing CaCO3 of a specified particle diameter in an arbitrary stage before the completion of its precondensation reaction. CONSTITUTION:An aromatic dicarboxylic acid (dimethyl ester) is reacted with a glycol in the presence of a catalyst, and in an arbitrary stage before the completion of the precondensation and before reaching an intrinsic viscosity of 0.2, 0.01-2.0wt%, based on the polyester to be formed, ethylene glycol slurry containing 2-9wt% CaCO3 of an average particle diameter of 0.01-0.8mum is added to the reaction system, and the polycondensation reaction is completed. EFFECT:A polyester low in dropout fault and useful as a magnetic tape base film can be obtained.
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