Method for producing polyesters with a reduced content of free acetaldehyde
AssigneeInventa-Fischer GmbH & Co. KG
InventorsEckehart Schaaf, Gerald Rafler, Rainer Hagen
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Abstract
The invention relates to a method for producing polyesters with a reduced content of free acetaldehyde from terephthalic acid and ethylene glycol via a catalyzed polycondensation in the melt and also the use of this method. The method is based thereby on the usage of highly active polycondensation catalysts, on the deactivation of these catalysts by the addition of phosphorous-containing inhibitors and the addition of acetaldehyde-bonding substances. The entire polycondensation is thereby implemented at temperatures beneath 280° C.
Claims34
Method for producing polyesters with a reduced content of free acetaldehyde from terephthalic acid and ethylene glycol via a catalysed polycondensation in the melt in which
- a) the catalyst is added before the polycondensation,
- b) after reaching an intrinsic viscosity (IV) of the melt between 0.63 and 1.00, which is achieved without solid-state postcondensation, an inhibitor is added for deactivation of the catalyst and
- c) next an excess of a substance which bonds the free acetaldehyde is added so that even subsequently released acetaldehyde is bonded,
- a temperature beneath 280° C. being maintained during the entire course of the polycondensation.
A method of producing packaging for food and beverages including the steps of:
- a) producing polyesters with a reduced content of free acetaldehyde from terephthalic acid and ethylene glycol via a catalyzed polycondensation in the melt in which;
- i) the catalyst is added before the polycondensation,
- ii) after reaching an intrinsic viscosity (IV) of the melt between 0.63 and 1.00, which is achieved without solid-state postcondensation, and inhibitor is added for deactivation of the catalyst, and
- iii) an excess of a substance which bonds the free acetaldehyde is added so that even subsequently released acetaldehyde is bonded, a temperature lower than 280° C. being maintained during the entire course of the polycondensation.
A method of producing beverage bottles including the steps of:
- a) producing polyesters with a reduced content of free acetaldehyde from terephthalic acid and ethylene glycol via a catalyzed polycondensation in the melt in which;
- i) the catalyst is added before the polycondensation,
- ii) after reaching an intrinsic viscosity (IV) of the melt between 0.63 and 1.00, which is achieved without solid-state postcondensation, an inhibitor is added for deactivation of the catalyst, and
- iii) an excess of a substance which bonds the free acetaldehyde is added so that even subsequently released acetaldehyde is bonded, a temperature lower than 280° C. being maintained during the entire course of the polycondensation.
A method of producing packaging films including the steps of:
- a) producing polyesters with a reduced content of free acetaldehyde from terephthalic acid and ethylene glycol via a catalyzed polycondensation in the melt in which;
- i) the catalyst is added before the polycondensation,
- ii) after reaching an intrinsic viscosity (IV) of the melt between 0.63 and 1.00, which is achieved without solid-state postcondensation, an inhibitor is added for deactivation of the catalyst, and
- iii) an excess of a substance which bonds the free acetaldehyde is added so that even subsequently released acetaldehyde is bonded, a temperature lower than 280° C. being maintained during the entire course of the polycondensation.
Dependencies are inferred from the claim text.