Dyes on Other Fibers

Disperse dyes can be used to produce light to medium deep shades on acrylic and modacrylic fibers [96, p. 639], The dyeing mechanism and process correspond to those used on PES and CA fibers (see Section 4.12). However, dyeing can be performed below 100°C. Addition of carriers is not required. The good migration properties of disperse dyes result in problem-free level dyeing. 

Poly (vinyl chloride) fibers (PVC) [96, pp. 642-645], are characterized by their flame retardance. They are dyed preferably with disperse dyes [50, p. 404], [6, pp. 611], As with modacrylic fibers, high temperatures must not be used because of shrinkage of the PVC fiber. Hence, some fibers are dyed at 60-65 °C with dyeing accelerants. Other PVC fibers can be dyed at 100°C without a carrier and a few even at 110°C. Dyes must be selected with regard to the lightfastness desired. 

Elastomeric polyurethane fibers [96, pp. 609-615], are contained in stretch articles and in knitted fashion materials. Light shades can be dyed tone-on-tone on polyamide-polyurethane mixtures with disperse dyes at 95-98°C and pH 6-7. However, the wetfastness of these dyeings on polyurethanes is lower than on polyamide. Because of the temperature sensitivity of polyurethane fibers, mixtures of elastomeric and polyester fibers must be dyed with small-molecular, rapidly diffusing disperse dyes in 30 min at 120 °C according to the HT process [148], Modified PES fibers that are dyeable at 100°C without a carrier are often used in mixtures with elastomeric fibers. In all dyeing processes for elastomeric fibers, dyeing equipment that permits low-strain guidance of the material and the lowest possible thermal stress are important. 

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