Producing a copolyester from a lower dialkyl ester of terephthalic acid, a glycol and a dicarboxylic acid

摘要

A process for producing a copolyester by copolymerizing the monomers from the ester interchange of a lower dialkyl ester of terephthalic acid and glycol and the direct esterification of a dicarboxylic acid and glycol using a catalyst system comprising manganese, lithium, antimony and preferably cobalt. The process includes the step of employing an effective catalytic amount of manganese and lithium in an ester interchange reaction where the lower dialkyl ester and glycol produce a first monomer; to the monomer adding a slurry of dicarboxylic acid and glycol and performing in the presence of the same catalystsa direct esterification reaction where the dicarboxylic acid and glycol produce a second monomer. For the copolycondensation of the monomers antimony and preferably cobalt are used as catalysts. A use for these copolyesters in composite fibres and nonwoven fabrics and a poly(-ethylene terephthalate-co-isophthtalate) containing specified amounts of Li, Mn and Sb are also claimed.