ApplicationNo. 771494 filed on 12/23/1996
US Classes:528/194, Two or more polycarboxylic acids or derivatives as reactants528/176, With polycarboxylic acid or derivative as reactant528/190, Reactant contains a fused- or bridged-ring other than solely as a polycarboxylic acid anhydride group528/193Two or more phenolic reactants
ExaminersPrimary: Mosley, Terressa
Foreign Patent References
International ClassC08G 064/00
AbstractAn improved process and apparatus for the production of a polyester or other condensation polymer is disclosed. In particular, polymerization is conducted in a reaction vessel equipped with a specially designed agitator that exposes the polymer melt partially filling the reaction vessel to inert gas flowing through the vessel. The agitator comprises a plurality of elements that lift a portion of a polymer melt in the reaction vessel and generate films of the polymer melt which films extends in planes that are parallel to the axis of the agitator and the flow of gas through the reaction vessel. In a preferred process, a melt of bis(2-hydroxyethyl) terephthalate, or its low molecular oligomers, obtained by esterifying terephthalic acid or transesterifying dimethyl terephthalate with ethylene glycol, is contacted with an inert gas at about atmospheric pressure in order to remove the reaction by-products and facilitate polymerization.