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1. (WO2001002461) METHOD FOR PRODUCING POLYETHYLENE TEREPHTHAHLATE MODIFIED WITH O-PHTHALIC ACID UNITS

Pub. No.:    WO/2001/002461    International Application No.:    PCT/DE2000/001926
Publication Date: Fri Jan 12 00:59:59 CET 2001 International Filing Date: Sun Jun 11 01:59:59 CEST 2000
IPC: C08G 63/183
C08G 63/78
Applicants: BUNA SOW LEUNA OLEFINVERBUND GMBH
WIEGNER, Jens-Peter
VOERCKEL, Volkmar
MUNJAL, Sarat
Inventors: WIEGNER, Jens-Peter
VOERCKEL, Volkmar
MUNJAL, Sarat
Title: METHOD FOR PRODUCING POLYETHYLENE TEREPHTHAHLATE MODIFIED WITH O-PHTHALIC ACID UNITS
Abstract:
The invention relates to a method for producing polyethylene terephthalate modified with phthalic acid units in such a way as to avoid high losses of phthalic acid during the esterification and the polycondensation and in such a way as to keep the advantageous application technology properties provided by the phthalic acid. According to the invention, a precondensate consisting of phthalic acid anhydride and ethylene glycol, produced without a catalyst, is added in the esterification and/or polycondensation stage. The ethylene glycol is used with a molar excess of 2 to 3.5 in relation to the phthalic acid anhydride.