Continuous polycondensation of bis:hydroxy-alkyl terephthalate - while blowing alkylene glycol vapour into reaction vessel to prevent sublimation on internal walls

摘要

While preparing a polyester by continuously introducing bis(hydroxyalkyl) terephthalate (I) or its oligomer into a polycondensation reaction vessel, alkylene glycol (II) vapour is continuously blown into the gas phase in the reaction vessel during the polycondensation. Polyester of high, uniform quality is continuously produced. The prod. is suitable for mfr. of fibres, films, and mouldings. The glycol pref. ethylene glycol or butylene glycol is blown into the reaction vessel through a nozzle such that it collides with and/or covers the internal walls of the vessel. The amt. of glycol is pref. 20-600 moles/hr. per 1000 kg of polyester intermediate (I).