PROCESS FOR THE PREPARATION OF POLYESTER

摘要

The polyester is prepared by treating, in the initial polymerising process, with the organic compound having at the same time one or more hydrophillic functional gp. and hydrophobic functional gp. having one or more tetra-valent atoms eg. Ti, Si, Zr and each of the functional gps. having two or more carbon atom; and then by adding the insoluble inorganic compound. The obtd. polyester is useful for the base film of a magnetic tape, and has excellent surface smothness and running property.