| abstract |
Macrocyclic polyester oligomers are converted to linear polyesters by contact at a temperature of about 160 DEG -300 DEG C. with a cyclic titanium catalyst such as di-(1-butyl)-2,2-dimethylpropane-1,3-dioxytitanate, bis(2,2-dimethyl-1,3-propylene) titanate or 1-(1-butoxy)-4-methyl-2,6,7-trioxa-1-titanabicyclo[2.2.2]octane. Such catalysts have high activity and produce linear or branched polyesters of very high molecular weight. |