Thiourea Dioxide is a replacement for Sodium Hydrosulphite / Thiosulphite used in vat dyeing, discharge printing and general colour stripping on cellulose and protein fibres.
It is an active reducing agent which removes the oxygen from indigo when combined with Soda Ash. Thiourea Dioxide is five times stronger than Sodium Hydrosulphite the alternative reducing agent.
Use 1 part Soda Ash to 4 parts Thiourea Dioxide to make a discharge paste for removing some synthetic dyes, especially Procion MX, from cellulose fibres.
Thiourea Dioxide is combined with Selectasine Indigo Discharge Medium at 8% of volume of discharge medium to activate it. Stir until all crystals have dissolved. Once activated, the discharge medium is effective for up to 18 hours.
The chemical has a shelf life of about two years, if stored in an air tight container. If the material shows a yellowish cast, then it may have lost some of its strength and you may need to use more. Please do a test sample first.
Take care with chemicals: can cause irritation to skin, eyes and respiratory system.
Thiourea Dioxide was previously referred to as Spectralite on this website 02/06/2021
