Exhaust fixation of cationic anti-bacterial products before dyeing as a more ecological process

Abstract

Natural fibres have terminal groups in their polymer structure that make them appropriate for anchoring other groups with specific functional properties. The most used chemicals so far based on this possibility are reactive dyes for cellulosic fibres discovered as far back as 1956. Twenty to thirty years on and other products were attached to cellulosic fibres for increasing the yield of reactive dyes or even dyeing with reactive dyes without salt. These were cationic groups that attracted the anionic dyes used. The process didn’t progress much into industrial application, mainly because of colour non-uniformity problems. Based on the experience of these technologies, we can go much further and attach longer chain cationic groups that have anti-bacterial properties. This has also been claimed by at least one company to be happening with their products. However, the application of these and other anti-bacterial products is invariably after dyeing, mainly by padding methods, with the use of resins. In this work we apply novel reactive long chain cationic products to cellulosic fibres by exhaustion method before dyeing, and promote the chemical reaction with the hydroxyl groups on the fibre. The main objective was to prove that the process is viable when applied before dyeing, and that it has benefits since no salt is not used, or used in less quantities, and there is no subsequent fixation of the anti-bacterial product by resins, eventually containing formaldehyde is necessary, making it globally into a much more ecological process.