| abstract |
PURPOSE: To obtain a polyester having improved easy slipperiness with little coarse particle content, by adjusting the coarse particle content of a slurry containing inert fine particles having a specific particle diameter till the completion of the initial condensation reaction, and adding a specific amount of the resultant slurry to the formed polyester. n CONSTITUTION: In obtaining a polyester consisting of 80mol% or more ethylene terephthalate in the repeating units, the coarse particle content of inert fine particles, e.g. kaolinite or barium sulfate, having 0.01W0.8μm particle diameter is adjusted to 0.5wt% or less particles having ≥5μ particle diameter based on the total particles (coarse particles ared removed by pulverizing, classifying or filtering, etc.), and 0.1W2.0wt% resultant slurry is added to the formed polyester to give the aimed polyester. n EFFECT: Dropout defects are slight in using as a base film for magnetic tapes. n COPYRIGHT: (C)1985,JPO&Japio |