Patent GB-975462-A (GB)
Title: Flame proofing of cellulosic materials
IPC: D06M15/431
Filed: 1961-11-20
Abstract: A polymerizable composition comprises an aqueous solution of a tetrakis (a -hydroxyorgano) phosphonium chloride having the formula <FORM:0975462/C3/1> in which R is hydrogen, lower alkyl having from 1 to 3 carbon atoms, chlorinated lower alkyl having from 1 to 3 carbon atoms, lower alkenyl having 2 or 3 carbon atoms or chlorinated lower alkenyl having 2 or 3 carbon atoms, a sulphite capable of combining with an aldehyde, a methylol-substituted triazine or triazone or dimethylol cyclic alkylene urea, and a strong acid salt of magnesium, zinc or a tertiary amine as a catalyst. An ammonium or primary amine strong acid salt may also be present as an additional catalyst. Sulphites capable of combining with aldehydes include inorganic sulphites and bisulphites and tertiary amine sulphites and bisulphites. A polymerization inhibiting effect can be obtained by contacting gaseous sulphur dioxide with an aqueous solution of the hydroxyorgano phosphonium chloride under alkaline conditions to convert SO2 to the sulphite ion. Preferably 0.9 to 2 moles of sulphite per mole of phosphonium chloride is used. Methylol melamine, dimethylol triazone, methylol melamine trimethyl ether are suitable triazines and dimethylol-ethylene and propylene ureas are specified urea derivatives. Strong acid salts specified are the sulphate, phosphate chloride, bromide and nitrate. The tertiary amine part of the salt may be triethylamine, triethanolamine, tri-isopropanolamine. Urea also may be added to the compositions. The compositions are used to impregnate cellulosic fibres to make them flame retardant curing of the resin on the fibre is effected by heating. In examples the aqueous compositions used comprise tetrakis (hydroxymethyl) phosphonium chloride, trimethylol melamine, urea, sodium sulphite, sodium bisulphite, catalyst (variously magnesium chloride, zinc chloride or nitrate, or triethanolamine sulphate) and, in some cases, ammonium sulphate. Specification 975,463 is referred to.ALSO:A process for preparing a flame-retardant cellulosic material comprises impregnating a cellulosic material with a polymerizable composition comprises an aqueous solution of a tetrakis (a -hydroxy organo) phosphonium chloride having the formula <FORM:0975462/D1-D2/1> in which R is hydrogen, lower alkyl having from 1 to 3 carbon atoms, chlorinated lower alkyl having from 1 to 2 carbon atoms, lower alkenyl having 2 or 3 carbon atoms or chlorinated lower alkenyl having 2 or 3 carbon atoms, a sulphite capable of combining with an aldehyde, a methylol substituted triazine or triazone or dimethylol cyclic alkylene urea, and a strong acid salt of magnesium, zinc or a tertiary amine as a catalyst drying the material and curing the resin in the material.  An ammonium or primary amine, strong acid salt may be present as an additional catalyst.  Sulphites capable of combining with aldehydes include inorganic sulphites and bisulphites and tertiary amine sulphites and bisulphites.  A polymerization inhibiting effect can be obtained by contacting gaseous sulphur dioxide with an aqueous solution of the hydroxyorgano phosphonium chloride under alkaline conditions to convert SO2 to the sulphite ion.  Preferably 0.9 to 2 moles of sulphite per mole of phosphonium chloride is used.  Methylol melamine, dimethylol triazone, methylol melamine trimethyl ether are suitable triazines and dimethylol-ethylene and propylene ureas are specified urea derivatives.  Strong acid salts specified are the sulphate, phosphate chloride, bromide and nitrate.  The tertiary amine part of the salt may be triethylamine, triethanolamine, tri-isopropanolamine.  Urea also may be added to the compositions.  In examples the aqueous compositions used comprise tetrakis (hydroxymethyl) phosphonium chloride, trimethylol melamine, urea, sodium sulphite, sodium bisulphite, catalyst (variously magnesium chloride, zinc chloride or nitrate, or triethanolamine sulphate) and, in some cases, ammonium sulphate.  Specification 975,463 is referred to.