METHOD OF PRODUCING POLYESTERS Russian patent published in 1998 - IPC

FIELD: polymer materials. SUBSTANCE: polyesters with controlled melting temperature applicable in textile, light, and furniture industries are prepared via glycolysis of isotropic and oriented polyethyleneterephthalate treated by ethylene glycol at 100-180 C for 30 to 180 min in presence of Zn, Mn, and Ca acetates' mixture as catalyst. Ethylene glycol is then stripped off and sulfur-containing acidic modifier is added in quantity 0.003 to 0.5% on the weight of polyethyleneterephthalate. Reaction mixture is allowed to stand and excess ethylene glycol is stripped off to yield polyester with specified melting temperature. During the synthesis, polycondensation may be continued after excess ethylene glycol is stripped off for further 30-60 min in presence of antimony trioxide. Polyester obtained is finally granulated. Melting temperature of product varies within the range from -20 to 258 C. EFFECT: facilitated polycondensation degree control. 2 cl, 2 tbl