Discussion On Improving The Perspiration-Light Colorfastness Of The Reactive Dyeings Of Cotton

A series of testing and analysis were discussed to find an effective way to improve the perspiration-light colorfastness of the reactive dyeings of cotton, in order to improve the quality of dyed cotton texiles.Compared different perspiration-light colorfastness testing standards, ATTS/AATCC 125-2004 is a reasonable selection for it is easy to operate and determine the end point of ligh exposure.After testing the tricolors of reactive dyes commonly used in practical production, the results show that the tricolors have low compatibility, and the tricolor mixtures exhibit low perspiration-light colorfastness.The factors influencing the perspiration-light colorfastness were systematically studied, including dye strength, alkali dosage, soaping, light exposure time, and fiber nature, and the results are as follows:The higher the dye strength is, the more the perspiration-light colorfastness improved; the less as the time of light exposure prolonged; the more sufficient the alkali dosage is, the higher the perspiration-light colorfastness will be; the perspiration-light colorfastness of reactive dyes is higher on silk textiles than on cotton textiles under the same dyeing condition; the perspiration-light and light colorfastness of dyed silk are in the equal level, this observation is not found for dyed cotton. All factors which help to improve the apparent color depth also enhance the perspiration-light colorfastness.To improve the perspiration-light colorfastness, some experiments were made in the selection of reactive dyes, other dyes and soaping. The results are as follows:Some kinds of reactive dyes have higher perspiration-light colorfastness; the perspiration-light colorfastness changes less and the color of the fabric changes more after the treatment of ferrous and copper salts. The perspiration-light colorfastness of cotton dyeings is improved to a certain extent when different dosages of direct and sulphur dyes are applied. Vat dyes have the good perspiration-light colorfastness of level 4 (the highest level is 5), and can be good substitutes for lower perspiration-light colorfastness reactive dyes. Vat dyeing is the best way to improve the perspiration-light colorfastness of dyed cotton fabrics.