PURPOSE: To obtain through direct polymerization high-quality polyester such as one with only a small amount of pressure increase during its spinning process, by depolymerizing esterified product from terephthalic acid and ethylene glycol followed by adding modifier to perform polycondensation.
CONSTITUTION: (A) Terephthalic acid and (B) ethylene glycol are subjected to direct esterification to prepare a product with an esterification rate ≥90% and molar ratio B/A of 1.07W1.3. This product is incroporated with (C) a polymerization catalyst and the component (B) to induce depolymerization to bring the molar ratio B/A of said product to 1.4W1.8 followed by adding, as a modifier, (D) 5-metal sulfoisophthalic bishydroxyethyl ester with an ester interchange rate ≥95% constituted by (i) sulfonate group-contg. isophthalic dialkyl ester and (ii) the component (B) to perform polycondensation, thus obtaining the objective polyester composed of ethylene terephthalate chief structural unit copolymerized with 0.5W5mol% of 5-metal sulfoisophthalic acid component.
KOBAYASHI YUKIO
YOSHIKAWA MASAHIRO
| JPS5893720A | 1983-06-03 | |||
| JPS5845452A | 1983-03-16 |