| abstract |
Process for producing a shaped article from a mixture of used polyester and fresh polyester, comprising the following steps: a. Melting of the washed waste polyester in a melting device, b. Adding diol to the melt of the waste polyester in or after the melting device, c. Filtration of the melt through melt filter, d. Mixing the melt of the waste polyester with a melt of fresh polyester from a melt reactor, e. Polycondensation of the melt mixture in a high-viscosity melt reactor under reduced pressure, f. Granulation of the polyester melt in an underwater granulator at a water temperature between 90 and 99 ° C, G. Separating the water from the granules with the least possible cooling of the granules, the granules having a temperature of at least 130 ° C, H. Transferring the thus obtained low-water granules after the water separation only by a passive conduit means directly or by means of a metering, in a Dealdehydisierungsbehälter, i. Treating the granules in Dealdehydisierungsbehälter means of a purge air flow, wherein the inlet temperature of the purge air flow between 180 ° C and 200 ° C and the residence time is 3 to 20 hours wherein the diol addition amount is controlled by the intrinsic viscosity (IV) in the main stream |