GB1258299A - - Google Patents

Abstract

1,258,299. Fire-fighting foam compositions. MINNESOTA MINING & MFG. CO. 24 Jan., 1969 [26 Jan., 1968], No. 4190/69. Heading A5A. A foaming composition for fighting fuel fires comprises water, a water-soluble foam-forming fluoroaliphatic compound, and a water-soluble film-forming fluoroaliphatic salt present in an amount of at least 2.5% by wt. of the foamforming compound, the film-forming salt being constituted by an acid component soluble to at least 0.2% by wt. in aqueous solution at 25‹C and having an ionisation constant greater than 1 x 10<SP>-5</SP>, and a base component soluble to at least 0.2% by wt. in aqueous solution of pH 5 at 25‹C, containing a trivalent nitrogen atom, and having a basic ionisation constant greater than 1 x 10<SP>-5</SP>. The composition forms a surface film on a hydrocarbon fuel surface, inhibiting vapour release therefrom. The foamforming compound is preferably a quaternary ammonium compound of formula and the film-forming compound a carboxylic or sulphonic acid fluoroaliphatic salt, particularly one of formula The composition may be formulated as a socalled 6% concentrate containing 0.5-10% by wt. foam-former, film-former in an amount 4-10% by wt. of the foam-former, and 15-95% by wt. water. A foam improver, e.g. polyoxyethylene glycol, a polyglycol or a vinyl or carboxyvinyl polymer may be added in an amount 5-15% by wt. of the concentrate, and a foam stabiliser, e.g. ethylene or diethylene glycol, glycerol or sorbitol in an amount 15-50%. The concentrate is diluted 16x with water for use.