Study of the application of modified thiourea dioxide discharge agent in D5 non-aqueous medium

In view of the low solubility of thiourea dioxide in water and its inertia to most chemical reagents, a novel non-aqueous medium, decamethylcyclopentasiloxane, was introduced to replace water in the grinding process for better dispersibility and discharge stability. In this study, the effects of different grinding methods on the particle size distribution and surface appearance of thiourea dioxide were studied. The influences of aqueous and decamethylcyclopentasiloxane media on the discharge stability of thiourea dioxide in discharge paste were compared. The whiteness, handle, and the tensile strength of the discharge-printed fabric were evaluated. The results showed that the wet grinding process endowed thiourea dioxide with smaller particle sizes and narrower size distributions in the presence of dispersants. Decamethylcyclopentasiloxane as a non-aqueous medium was beneficial in maintaining good discharge stability of thiourea dioxide for a longer time. The fabrics discharged by the prepared thiourea dioxide printing paste had favourable whiteness, good handle, and acceptable tensile strength.