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US 5,708,124 AGranted
Process for the solid state polycondensation of polyester resins
AssigneeSinco Engineering S.p.A.
InventorsHussain Ali Kashif Al Ghatta, Dario Giordano
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Abstract
Process for the solid state polycondensation of polyester resins, where an inert gas is circulating in a moving bed of polymer at a temperature between 180.degree. and 230.degree. C., characterized by the fact that the ratio by weight between the gas rate of flow per hour and that one of the discharged polymer is lower than 0.6.
Claims19
Continuous process for solid state polycondensation of aromatic polyester resins, comprising the steps of:
- feeding the resin through the top of a moving bed reactor and discharging the resin from the bottom;
- and circulating an inert gas counter or equicurrent with the resin, wherein the reactor has a temperature between 180.degree. C. and 220.degree. C., with resin average residence times long enough to obtain an increase of polymer intrinsic viscosity of at least 0.1 dl/g, and wherein a ratio R by weight between the gas rate of flow per hour and the rate of flow per hour of the polymer discharged from the reactor is lower than 0.6.
Dependencies are inferred from the claim text.