Tetrakis(hydroxymethyl)phosphonium chloride-Urea

THPC-U is the common abbreviation for the Tetrakis (hydroxymethyl) phosphonium chloride-Urea complex. It is a key chemical used primarily as a flame retardant precursor.

1.Basic information:

Name: Tetrakis(hydroxymethyl)phosphonium chloride-Urea complex ,THPC-U

CAS:27104-30-9

Appearance: Typically a clear, colorless to pale yellow liquid.

Solubility: Miscible with water.

2 Application:

The primary and most important application of THPC-U is as a durable flame retardant finishing agent for textiles.

Textile Flame Retardancy: It is predominantly used for treating cellulose-based fabrics like cotton, rayon, and linen. The process works as follows:

-The fabric is impregnated with an aqueous solution of THPC-U.

-Upon curing (drying and baking at high temperatures), the THPC-U reacts with the urea and the cellulose fibers themselves.

-This reaction forms an insoluble, cross-linked polymeric network within the fabric.

-This network acts as a permanent barrier to flame, providing durable flame resistance that can withstand multiple launderings.

3. Advantages:

Durability: The insoluble polymer formed within the fibers ensures the flame retardancy survives over 50 industrial launderings, often lasting the entire service life of the garment.

Excellent FR Performance: Dramatically increases the Limiting Oxygen Index (LOI) of cotton from ~18% (highly flammable) to over 28% (non-flammable or self-extinguishing).

Preserved Fabric Hand: Unlike stiff barrier coatings, this process results in fabrics that remain relatively soft and breathable.

Ideal for Cellulosics: Exceptionally effective on cotton, rayon, and other natural cellulose fibers.

4. Health, Safety:

Toxicity of Precursors: The raw material, THPC, is corrosive and toxic, causing severe skin burns, eye damage, and respiratory irritation.