Discoloration of Light Dyed Woven Fabrics at Industrial Washing

Abstract

Changes of shade of light dyed samples under the influence of an optical brightener in the detergent at industrial washing in the rotary washing machine are similar to those when clean samples are washed in the laboratory machine. It was washed together with dirty table linen. The soilings from the washing bath have no decesive influence if it is washed with an intensive pre-washing process. On white and blue samples the saturation of shade is increased, whereas the saturation on yellow and red samples is decreased. Changes of shade at washing can be reduced to acceptable limits if the material is pretreated with optimal amounts of optical brightener. The other possibility to wash the material before laying it on the table is less acceptable, especially in the household use. In addition, changes of shade after such treatment in subsequent washing processes are a little higher than when using optimal concentrations of optical brighteners at the plant.