| 摘要 |
PROBLEM TO BE SOLVED: To provide a modified polytrimethylene terephthalate having improved tone of color, strengths, processability and resistance to alkali-lysis, and further having excellent dyeability by a cationic dye. SOLUTION: This method comprises the steps of charging polytrimethylene terephthalate and polytrimethylene terephthalate copolymerized with a sulfonate to a twin-screw extruder with vent to melt and knead so that the content of the sulfonate becomes 0.1 to 5 mol% based on total trimethylene terephthalate unit, and proceeding polymerization using the twin-screw extruder unitll the intrinsic viscosity of the obtained polyester exceeds the average by mol fraction between the polytrimethylene terphthalate and the copolymerized polytrimethylene terephthalate. |
