METHOD FOR PREPARING COMPLEX POLYESTERS AND COPOLYESTERS Russian patent published in 2004 - IPC

FIELD: organic chemistry, polymers, chemical technology. SUBSTANCE: invention relates to preparing thermostable complex (co)polyesters used as structural and insulating polymeric materials. (Co)polyesters are prepared by interaction on the first stage of terephthalic or 2,6-naphthalene dicarboxylic acid dimethyl ester or their mixture with 1,4-butandiol, or ethylene glycol, or their mixture in the melt at 150-250 C in the presence of tetrabutoxytitanium and a thermostabilizing agent. As a thermostabilizing agent method involves using the synergetic mixture 0.1-0.5% of mass of (co)polyester of the hindered tetraphenol pentaerythryltetrakis-(3,5-di-tert. -butyl-4-hydroxyphenyl)-propionate, 0.1-0.5% of mass of (co)polyester of trinonylphenylphosphite or tri-(2,4-di-tert.- butylphenyl)phosphite and 0.01-0.5% of mass of (co)polyester of sodium or calcium salt of hypophosphorous acid. On the second stage the formed product is subjected for polycondensation at 220- 290 C under vacuum 0.1-0.3 mm of mercury column. Invention provides preparing (co)polyesters with high thermal stability of melt in processing and the initial content of terminal carboxyl groups in the amount less 40•10^-6 g-equiv./g. EFFECT: improved preparing method. 1 tbl, 1 dwg