MODIFIED POLYESTER AND CONTINUOUS METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain an inexpensive modified polyester excellent in spinnability and productivity while having sufficient dyeability by a cationic dye. SOLUTION: This polyester has ethylene terephthalate as a main recurring unit and contains 1.0-2.5 mol% metal sulfonate group-containing isophthalic acid component in the acid component. The polyester is characterized in that mol% of DEG contained in a glycol component is 4.5-5.5 mol% and a ratio of maximum value [η]max of intrinsic viscosity to minimum value [η]min thereof satisfies the formula 1.0<=[η]max/[η]min<=1.02.