A novel resist technique based on secondary amines for the printing of cotton with reactive dyes

Abstract

In an earlier paper we have described sulphite‐based resist printing using ink‐jet procedures. This paper describes an alternative approach to sulphite inactivation of vinylsulphone dyes by using secondary amines to inactivate fluoro‐s‐triazine dyes while maintaining the reactivity of the vinylsulphone dyes. Monofluoro‐s‐triazine reactive dyes are padded onto cotton fabrics and then deactivated by ink‐jet printing with a suitable secondary amine formulation to produce a white image on a solid ground colour after appropriate fixation and soap‐off procedures have been undertaken. A coloured image can be achieved by overprinting the resist‐printed areas with a coloured ink formulation containing a β‐sulphatoethylsulphone‐type reactive dye; such dyes form a β‐bis‐alkylaminoethylsulphone dye via reaction with the secondary amine. This latter dye ‘unblocks’ during a mildly acidic steaming process to form the reactive vinylsulphone dye, and so, unlike the monofluoro‐s‐triazine dye, is not deactivated towards subsequent covalent reaction with the cotton substrate.