Can Thiourea Dioxide Be Used for Dyeing-Machine Cleaning?

Direct Answer

Direct Answer Yes, and our technical data sheet lists machine cleaning as a separate application.

What the cleaning is for

Removing dye scale, oligomer and auxiliary deposits from the machine wall, pipework and filters so that changing shades does not cause cross-contamination, specks or shading. Polyester oligomer is the main source of that scale, and a reductive clean targets it directly.

Recommended recipe

Advantages over hydrosulfite cleaning

• No sharp odour, and no residual sulphur smell in the machine afterwards, so the next batch is less likely to pick up an odour
• Less aggressive towards stainless steel vessels and pipework
• Spent cleaning liquor can go through conventional physico-chemical plus biological treatment

Operating notes

• Drain residual liquor first so the clean does not run in the same bath as oxidising auxiliaries
• Add the caustic soda shortly before use rather than preparing the bath in advance
• On high-temperature pressurised machines follow the specified heat-up and cool-down sequence; do not skip depressurisation to save time
• Rinse with hot water before loading the next batch

Bottom line

1. 0 to 3.0 g/L of thiourea dioxide with 5.0 ml/L of caustic soda (38 Be) and 0.5 to 1.5 ml/L of detergent, circulating at the boil for 10 to 60 minutes.

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. 我司应用工艺资料（染缸清洗与还原清洗处方）