METHOD OF SYNTHESIS OF POLYESTER THERMOPLASTICS Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: method involves reesterification of terephthalic acid dimethyl ester and 1,4-butanediol at 160-220 C in the presence of tetrabutoxytitanium. At the second stage polycondensation of synthesized di-(β-hydroxybutyl)-terephthalate is carried out at 220-250 C, under residual pressure 0.1-0.8 mm mercury column followed by distilling off 1,4-butandiol and oligobutylene terephthalate formation. At the third stage at distilling off degree of 1,4-butanediol 50-70% (this value corresponds polycondensation degree of di-(b-hydroxybutyl)-terephthalate 2-4 and molecular mass of oligobutylene terephthalate 530-970) polyhydroxytetramethylene glycol is added to the process, and process is continued for 2 hr (not less) under vacuum 0.1-0.8 mm mercury column up to preparing block-copolymer at the content of "elastic" blocks 30-70% and that of "rigid" blocks 30-70% Residual deformation of prepared thermoelastoplastics is 32-44% that is close to the value of dienostyrene thermoelastoplastics and vulcanized rubber. Material is used for making structural articles showing enhanced thermal stability. EFFECT: improved method of synthesis. 2 tbl