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

摘要

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.