The Light Fastness of the Reactive Dyes on Cationized Cellulose

Conventional dyeing of cellulose with reactive dyes requires the use of huge quantities of electrolytes and alkalis and the temperature between 60–90°C. Using the above conditions a stable covalent bond is formed between the reactive group of the dye and the hydroxyl group of cellulose. Cationization of cellulose allows to carry out reactive dyeing without electrolytes and alkalis even at room temperature. The dye, depending on the cationic modifier used, can form only ionic bond between sulfonic group of the dye and quaternary group of the modifier or also covalent bond between reactive group of the dye and hydroxyl group of the modifier. In this work we investigate how light fastness is affected by the type of bond with which the dye bound to the cationized cellulose. So far, such research has not been published. We found that the light fastness of the reactive dyeings on cationized cellulose was lower compared to non-cationized cellulose and depends on the kind of modifier used: chlorocholine chloride, 3-chloro-2-hydroxy-propyltrimethylammonium chloride and copolymer [(chloro-methyl)oxirane +1 H-Imidazole]. Density electron changes of ionic bonds between quaternary group of modified cellulose and sulfonic group of reactive dyes were analyzed in relation to the fading process.