Acid red 33

Acid Red 33 (CAS 3567-66-6) is a synthetic azo dye supplied as a sodium salt, commercially identified under the names Red 10B, AKA227, and RED 33. It carries no assigned E-code for food use in the EU and belongs to the broader class of sulfonated azo colorants used across regulated and industrial applications.

In cosmetic formulations, Acid Red 33 imparts red to pink hues in rinse-off and leave-on products by adsorbing onto keratin and other protein-based substrates through ionic interaction. In textile and leather processing, it bonds to nylon, wool, and treated leather under acidic conditions, delivering consistent depth of shade with controlled exhaustion rates.

The dye is available in solid form and must comply with REACH registration requirements for supply within the EU. Procurement should confirm purity specifications and batch documentation, as accepted quality standards vary by end-use sector. Packaging formats are available on request.