Flame retardant finish - Fire Proof

Flame Retardant finish - part-4

Application on Textiles:

One of the most preferred processes of applying FR on cotton is the "Precondensate"/NH3 process. This is an application of one of several phosphoniums "precondensates," after which the fabric is cured with ammonia, then oxidized with hydrogen peroxide Precondensate is the designation for a Tetrakis-hydroxymethyl phosphonium salt pre-reacted with urea or another nitrogenous material. The amount of anhydrous sodium acetate is approximately 4% of the amount of precondensate used. Some precondensates are formulated along with the sodium acetate. Softeners are also added along with precondensates.

The pH of the pad bath should be approximately 5.0.The amount of flame retardant required depends primarily on fabric type, application conditions, and test criteria to be met. Screening experiments should be conducted to determine the minimum application level for a fabric. Application of FR to fabric can be accomplished with conventional padding, padding with multiple dips and nips, followed by 30 to 60 seconds dwell gives good results. A critical factor in the successful application of precondensate/NH3 flame retardant is control of fabric moisture before ammoniation. Generally, moisture levels between 10% and 20% give good results.

Author: C.N.Sivarama Krishnan
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