Controlling Nylon Dyeing by Dye and Chemical Metering

Abstract

Closed-loop control of the dosing of dyes and chemicals is used to obtain an on-tone build-up of shade in dyeing polyamide fibers with a binary mixture of monosulfonated acid dyes. Computerized dosing pumps control the pH, the dyebath concentrations of the individual dyes, and the total sorption of each dye during the process. This real-time, closed-loop adaptive control yields good reproducibility and uniform shade build-up in a laboratory dyeing machine. It is possible to reuse a dyebath containing residual dyes and chemicals from a previous dyeing.