KINETICS OF DYEING OF FORMALIZED AND FORMALIZED, ACID-TREATED POLY(VINYL ALCOHOL) FIBERS WITH THREE DIRECT DYES

The kinetics of the dyeing of formalized poly (vinyl alcohol) (PVA) fiber (I) and its acid treated product (II) with three direct dyes have been studied at 70 and 80°C. Each dyeing was made in a finite bath (liquor ratio 1:2000) with 1×10-5 mol/1 of a direct dye and with 0.1 mol/1 of sodium chloride. The apparent diffusion coefficients (D) (Table 3) decreased with an increase in the degree of the formalization. The values decreased in the order, Rhoduline Red B_??_Orange S>Scarlet 4BS, but the equilibrium sorption of dye (C∞) (Table 2) increased in the reverse order. D and C∞ values for II were fairly larger than those for I. It is suggested that the kinetics of the dyeing of I and II with direct dyes are remarkably affected by the cross-linking formed in the formalization reaction of the polymer and by the chemical constitution and size of the dye molecules.