Can Thiourea Dioxide Be Used for Color Stripping?

Direct Answer

Direct Answer Yes, and it is one of the most established hydrosulfite replacement routes in stripping. Our technical data sheet sets out the substitution relationship and the recipe.

What it suits

• Cotton dyed with reactive dyes
• Polyester dyed with disperse dyes
• Reductive stripping of wool and silk
• First-time stripping, shading correction and rework

Recommended recipe

Substitution relationship

Our technical data sheet replaces the sodium dithionite charge with about one third of the thiourea dioxide weight. Because there are so many dye classes there is no universal formulation, so a preliminary trial is necessary, with reference to the dyestuff supplier recommendations where relevant.

Known weakness

Performance is insufficient on black and grey shades, where it is normally blended with hydrosulfite at roughly 1 : 10.

Bottom line

1. 0 to 3.0 g/L of thiourea dioxide with 8.0 to 15.0 ml/L of caustic soda (38 Be) at the boil for 20 to 60 minutes, at a substitution ratio of about one third of the hydrosulfite weight.

Sources

1. 我司产品技术数据表《THIOUREA DIOXIDE Technical Data Sheet》（TDO-TDS，签发日期 2024-05-08）
2. Performance Evaluation of Hydrose and Thiourea Dioxide as Stripping Agents for Reactive Dyes，AJER 7(2), 2018，https://www.ajer.org/papers/Vol-7-issue-2/ZF070201250258.pdf