INVESTIGATION OF THE INFLUENCE OF LIGHT STABILIZERS ON THE LIGHTFASTNESS OF COTTON KNIT FABRIC DYED WITH REACTIVE DYES

Abstract

The goal of the work is to study the effect of light stabilizers on the lightfastness of colours of cotton knit fabric dyed with reactive dyes. The study was carried out using a cotton 1+1 rib knit fabric with a surface weight of 150 g/cm², prepared by the combined technology of boiling and bleaching. Dyeing of the fibrous material was carried out using Bezaktiv reactive dyes in a batch method at a concentration of 0.3% by weight of the material. UV absorbers 2,5-dihydroxyacetophenone, 2,4-dihydroxybenzophenone, phenyl salicylate and antioxidants – diatomic phenols – hydroquinone, pyrocatechol and resorcinol were chosen as light stabilizers. In the work, the light stabilization of cotton knit fabric was carried out after dyeing with reactive dyes and washing the dyed knit material. The technological mode of application of the studied light stabilizers was to impregnate a knit fabric, drying and curing the material. The individual effect of light stabilizers on the colour change of dyed knit fabric samples and the photodestruction kinetics of dyes were investigated. The insolation of the samples was carried out on a device with a mercury-tungsten lamp RF 1201 BS ("REFOND"). After treatment and insolation, the total colour difference dE of knit samples were determined compared to untreated material using a TCR-200 colorimeter ("PCE Instruments"). The results obtained indicate that the change in the initial colours after treatment with light stabilizers depends on the colour of the dye and on the type of light stabilizer. The greatest colour changes are observed with phenyl salicylate, pyrocatechol and resorcinol. It has been established that UV absorbers exhibit a light-shielding effect to a greater extent than antioxidants. The obtained experimental results also indicate the need for the simultaneous use of UV absorbers and antioxidants in order to efficiently stabilize dyed cotton knit fabric. The individual effect of light stabilizers – UV absorbers and antioxidants – on the lightfastness of colours of cotton knit fabric dyed with Bezaktiv reactive dyes is investigated. It was established that for effective light protection of colours of cotton knit fabric dyed with reactive dyes, the simultaneous use of UV absorbers and antioxidants is necessary