Copolyester prepared from an acyloxybenzoic acid and polyethylene terephthalate modified with p-hydroxyethoxybenzoic acid

摘要

Disclosed is a copolyester comprised of the following divalent radicals: <IMAGE> (A) OCH2CH2O (B) <IMAGE> (C) <IMAGE> (D) wherein the range of radical (C) is from about 50 to about 80 mole percent, based on the total moles of (A) and (C) combined and the range of radical (D) is from about 20 to about 70 mole percent, based on the total moles of (A) and (D) combined. The copolyesters of this invention are prepared by a process comprised of two steps. The first step comprises forming a fragmented polyester by acidolysis of a starting polyester with an acyloxybenzoic acid. The second step comprises increasing the inherent viscosity of the fragmented polyester to form the copolyester of the invention. Radical (A) of the copolyester is contributed from the dicarboxylic acid portion of the starting polyester. Radical (B) of the copolyester is contributed from the ethylene glycol portion of the starting polyester. Radical (C) of the copolyester is contributed from the acyloxybenzoic acid, and will be recognized as the radical remaining after removal of the acyl and hydroxy groups from the acyloxybenzoic acid. Radical (D) of the copolyester is contributed from a combination of the ethylene glycol and the ester of p-hydroxybenzoic acid used in preparing the starting polyester. The copolyesters of this invention exhibit unobvious mechanical properties.