Dyeing
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The processed fabrics were pre-wetted in 1% owf Triton X100 (t-octylphenoxypolyethoxyethanol) nonionic surfactant. The dye trichromy: C.I. Acid Red 1, C.I. Acid Yellow 17, and C.I. Acid Blue 45 was recommended and supplied by Organic Dyestuffs Corporation, RI. In addition, C.I. Acid Black 1 was included to extend the color palette. The dyes are mono- and disulfonated level acid dyes. They were applied at 3% owf, LR 30 :1, in an Ahiba Texomat G VIIIB, 12 position with TC-IOl control unit (Datacolor, NC). The dyebaths were composed of acetic acid buffer (2 M acetic acid and 2 M sodium acetate mixed in a ratio of 1:1) for pH 4.0-4.5. In addition, 0.1% owb sodium sulfate, and 1% owf Albegal B (Ciba, NC) were added as levelers. The dyeing procedure followed the conventional time/temperature profile for wool dyeing: 230C dwell for 10 minutes, ramp to 60°C at 1°/minute, 60°C dwell for 10 minutes, ramp to 90°C at 1°”/minute; 90°C dwell for 30 minutes, cool to 80°C. After dyeing, fresh baths were constituted with 1% owb Triton X-100 to remove surface and occluded dye. The fabrics were agitated at room temperature for 20 minutes before final rinsing in water. The amount of dye remaining in the dyebaths at 0 minutes (23°C), 10 minutes (23°C), 20 minutes (40° C), 30 minutes (60°C), 50 minutes (70°C), 60 minutes (80°C), and 120 minutes (90°C) was measured on the Cary 50 UV-VIS Spectrophotometer at the wavelengths of maximum absorption for the individual dyes. Dye uptake by the fabrics at various times of dyeing with reference to the standard curves of dye concentration versus absorbance for each individual dye, led to determinations of dyebath exhaustion (%E), exhaustion times (minutes), and rate of dye uptake (min^sup -1^). All baths exhibited 95% or greater exhaustion. The dyebath exhaustion, %E, was calculated according to the ratio [(C^sub 0^ - C^sub t^)/C^sub 0^] × 100 where C^sub 0^ and C^sub t^ are the original dyebath concentrations and dyebath concentrations at times, 0 and ^sub t^, respectively.
