| abstract |
A fiber made from a polyester containing 2-20 mole % of a comonomer component represented by general formula (1); yarns wherein the above fibers are used, i.e., blended yarns composed of filaments with different shrinkage percentages, yarns of core-sheath type, and blended staple yarns; and composite fibers containing the polyester as a component. The invention fiber has a low birefringence and excellent dyeability and bathochromic effect. Further it has, depending on the stretching conditions, not only a high shrinkage percentage but also a high shrinkage force and remarkably excellent lightfastness, thus being useful as a substitute for conventional high-shrinkage fibers. In formula (1) R₁ to R₁₀ represent each a group selected from an ester-forming functional group, hydrogen and alkyl, provided one or two of them is (are) ester-forming functional group(s); and x is 0 or 1 and y is an integer satisfying the condition of 1 ≦ x+y ≦ 3. |