What Is the Recommended Laboratory Test?

We recommend a 4-point dosage screening test: fabric = customer production polyester fabric; liquor ratio 1:10–1:20; temperature 70–80°C; time 15–20 min; Thiourea Dioxide 0.5 / 1.0 / 1.5 / 2.0 g/L; NaOH 1–2 g/L as a starting range.

Then compare against the customer's existing hydrosulfite recipe.

Measure ΔE + K/S + whiteness + fastness + tensile strength.

A published polyester reduction-clearing protocol, for example, uses 2 g/L sodium hydrosulfite and 2 g/L NaOH at 70–80°C for 15–20 minutes.