| abstract |
PURPOSE: To produce the titled polyester low in content of coarse particles, by adding an ethylene glycol slurry containing CaCO 3 of a specified particle diameter in an arbitrary stage before the completion of its precondensation reaction. n 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, 0.01W2.0wt%, based on the polyester to be formed, ethylene glycol slurry containing 2W9wt% CaCO 3 of an average particle diameter of 0.01W0.8μm is added to the reaction system, and the polycondensation reaction is completed. n EFFECT: A polyester low in dropout fault and useful as a magnetic tape base film can be obtained. n COPYRIGHT: (C)1985,JPO&Japio |