| 摘要 |
1,187,951. Dry powder fire extinguishing compositions. NU-SWIFT INTERNATIONAL Ltd. 21 April, 1967 [23 April, 1966], No. 17852/66. Heading A5A. Foam-compatible dry powder fire-extinguishing compositions containing free-flow additives are characterised in that the additives are coated with highly fluorinated and/or perfluorinated compounds, usually in an amount 1% coating based on the additives weight. "Highly" fluorinated is defined as at least 50% replacement of the carbon-bonded hydrogen atoms by fluorine. The fluorinated compounds may be surface-active long-chain carboxylic or sulphonic acids, e.g. betaines, or alkali metal ammonium or amine salts thereof. Exemplified compositions are as follows:- (1) 95.4% (by wt.) sodium bicarbonate coated with 0.6% of a ketone-aldehyde resin dissolved in methylene chloride, plus 4% chalk coated with a sodium salt of a perfluorosulphonic acid. (2) 94.3% potassium bicarbonate coated with 10.7% of a silicone resin in methylene chloride, plus 5% magnesium carbonate coated with a potassium salt of a highly fluorinated carboxylic acid. (3) 40% ammonium sulphate, 41% ammonium phosphate, 5% chalk and 5.3% barytes coated with 0.8% polyacrylic resin in methylene chloride, plus 7% barytes coated with a fluorinated betaine. |
