Verfahren zur Herstellung von Polyestern mit reduziertem Gehalt an Acetaldehyd

EP 1188783 A UPAB: 20020815 NOVELTY - The production of polyester with a reduced content of free acetaldehyde involves melt-polycondensation of terephthalic acid and ethylene glycol at below 280 deg. C with (a) addition of catalyst before polycondensation, (b) deactivation of catalyst when the intrinsic viscosity of the melt reaches 0.63-1.00 and (c) addition of acetaldehyde-binder in excess. DETAILED DESCRIPTION - A method for the production of polyester with a reduced content of free acetaldehyde by melt-polycondensation of terephthalic acid and ethylene glycol involves (a) adding the catalyst before polycondensation, (b) adding an inhibitor to deactivate the catalyst when the intrinsic viscosity (I.V.) of the melt reaches 0.63-1.00 (without solid-phase post-condensation) and (c) then adding excess acetaldehyde-binding substance, the entire polycondensation being carried out at below 280 deg. C. USE - For the production of packaging for food and drinks, beverage bottles and packaging film (claimed). ADVANTAGE - Enables the production of high-mol. wt. polyester granules with a low acetaldehyde content for the manufacture of food and drink containers without solid-phase post-condensation and without expensive degassing apparatus. This reduces the risk of unacceptable odors and flavors in, e.g., packaged food