Tetrakis(hydroxymethyl)phosphonium chloride

Tetrakis(hydroxymethyl)phosphonium chloride (CAS 124-64-1), commonly sourced as THPC, is a reactive phosphorus-based flame retardant.

Where is Tetrakis(hydroxymethyl)phosphonium chloride used?

• Textile finishing: reacted with nitrogen-containing compounds such as urea or melamine to produce wash-durable flame-retardant finishes on cotton and cellulosic fabrics
• Leather processing: applied during wet finishing to meet fire resistance standards required in automotive upholstery
• Pulp and paper: flame retardant and cross-linking agent, improving dimensional stability in treated specialty papers and industrial products
• Building and construction: flame-retardant treatment of nonwoven materials and insulation substrates
• It functions by chemically bonding into fibrous or polymer matrices during curing, delivering durable flame retardancy rather than surface-level protection.

Commercial specifications

• Aqueous solution, typically at 80% active content
• Drums and intermediate bulk containers