| abstract |
The invention relates to a dyeability improver for polyester fiber materials. It comprises: a polyester copolymer which is obtained by condensation-polymerizing a dibasic acid ingredient including 15-65 mol% dibasic acid having a sulfonic acid base with a dihydric alcohol ingredient comprising a polyethylene glycol having a molecular weight of 900-3,500 and which has a molecular weight of 3,000-30,000 and has 10-40 mass% polyoxyethylene chain in the molecule; and at least one compound selected from the group consisting of styrenated phenol/alkylene oxide adducts and higher alcohol/alkylene oxide adducts. The improver can eliminate problems in the dyeing of polyester fiber materials, such as polyester oligomer adhesion, dye fouling, and foreign-matter fouling. |