| 摘要 |
<p>A polyester which has ethylene terephthalate units as main repeating units, is made up of monomer units wherein the acid units contain 2.0 to 3.0 mol% isophthalic acid units having a metal sulfonate group, and contains 9.0 to 13.0 wt.% polyalkylene glycol having an average molecular weight of 1,000 to 10,000 in the polymer, characterized in that the content of DEG units in all the glycol units is 4.7 to 5.7 mol% and that the ratio of the maximum of intrinsic viscosity, [θ]max, to the minimum thereof, [θ]min, is from 1.0 to 1.02. The modified polyester is reduced in viscosity decrease and coloration during melt spinning while retaining sufficient solubility in aqueous alkali solutions. It is excellent in spinnability and productivity.</p> |
