Albright & Wilson Limited

Robert Cole

Geoffrey Hand

James E Stephenson

A process for the flame-retardant treatment of a cellulosic fabric by impregnating a fabric with an aqueous solution of a tetrakis (hydroxyorgano) phosphonium (THP) and then at least partially drying it. The partially dried impregnated fabric is passed at a speed of 30 to 100 m/minute once through a chamber containing ammonia for a single cure. Both the moisture contained in the fabric and water produced as a by-product of curing are volatilized and condensed on an interior wall of the chamber and flow down the walls to a drain for removal of the condensed water from the apparatus. The process further includes measuring the rate of ammonia in the gas fed into the chamber, determining the ammonia content of the gas and measuring the temperature within the chamber, for maintaining the initial concentration of ammonia in the gas at 70% to 90% by volume and for maintaining the ratio of ammonia input to the THP composition in the range of at least 1.2 to 1, on the basis of ammonia to phosphorus; withdrawing the treated fabric from the chamber, removing at least some of the gas from the chamber; and recycling at least some of the gas back into the chamber.

Process for the flame-retardant treatment of textiles

Flame retardant cellulosic fabrics having reduced shrinkage are obtained by treatment involving reaction of fabric with a non self-condensing methylolamide under aqueous acid conditions, followed by treatment of fabric with tetrakis hydroxylmethyl phosphonium compound or condensate and then curing the ammonia.

Fabric treatment processes

Flame retardant cellulosic fabrics having reduced shrinkage are obtained by treatment of fabric with a tetrakis hydroxymethyl phosphonium compound or condensate and then curing with ammonia, followed by treatment involving reaction of the fabric with a non self-condensing methylolamide under aqueous acid conditions.

Flame retardant treatment of cellulose fabric with crease recovery:

The cure efficiency for the treatment of fabrics with tetra(hydroxymethyl) phosphonium compounds and their precondensates e.g. with urea especially from THP sulphate, is improved by passing gaseous ammonia through impregnated fabric then wetting the fabric and completing the cure with more ammonia, preferably again passed it through the fabric.

Flameproofing textiles

An improved process for manufacturing tetrakis (hydroxymethyl) phosphonium amide condensation product without the formation of a precipitate. Urea or thiourea is added to the tetrakis (hydroxymethyl) phosphonium salt having an anion formed from a dibasic or tribasic or polybasic acid. The said salt is in aqueous solution. The pH of the aqueous solution of said salt is adjusted to the range of 4-6.5 when the urea or thiourea is added to the salt. The proportion of said salt to said urea or thiourea is 1:0.05-0.5 (molar). The sulphuric acid salt is preferred. The process produces an improved aqueous product substantially free of insolubles.

Flameproofing agents

A process for flameproofing cellulosic fabrics which comprises impregnating the fabric with an aqueous solution of a THP salt with or without condensation with a nitrogen-containing compound, and treating the impregnated fabric with ammonia to produce a cured resin, wherein the treatment with ammonia is carried out by passing the impregnated fabric through seals into and out of a closed chamber and in contact with at least one duct located in the chamber and having one or more orifices through which gaseous ammonia is caused to issue and pass through the fabric over its width, the chamber being provided with means to prevent condensed water formed by evaporation and/or chemical action from dripping on to the fabric.

Flameproofing of textiles

A process for flameproofing cellulosic textile fibres which comprises impregnating the fabric with an aqueous solution containing a pre-condensate of urea and a THP salt together with any excess of the THP salt necessary to make up a ratio of urea to THP lying between 0.05:1 and 0.25:1 molar, the solution being neutralized by the addition of an alkali or base to a pH in the range 5 to 8, and treating the impregnated fibres with ammonia to form a cross-linked polymer.

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Dudley, United Kingdom

Robert Cole