What Is the Recommended Laboratory Test?

Direct Answer

Direct Answer Run it in three stages, reference plus gradient plus repeat, so that the whole process window is mapped in one campaign rather than committing to production on a single point test.

Stage 1: preparation

• Take fabric or yarn from the same batch and specification and cut equal test specimens
• Keep one set processed exactly on the current hydrosulfite recipe as the reference

Stage 2: gradient design

Fix alkali and temperature first and run the dose gradient, then adjust alkali and temperature in turn once the dose range is known.

Stage 3: measurements

• Performance: whiteness, stripping efficiency, colour difference delta E, rub and wash fastness
• Safety: retained tensile strength, weight loss, handle
• Economics: specific consumption in g/kg of fabric and chemical cost per tonne

Stage 4: repeat

Take the best-performing conditions, repeat three times to confirm reproducibility, then scale up to a works trial. Only a recipe that repeats three times is a reliable recipe.

Bottom line

Reference, gradient and three repeats, centred on the one third substitution ratio. A single point test passing does not mean the process is ready.

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）