| 摘要 |
1,264,681. Fire-protective films for hydrocarbon liquids. MINNESOTA MINING & MFG. CO. 18 April, 1969 [19 April, 1968], No. 20038/69. Heading ASA. An aqueous composition capable on dilution with water of forming a vapour-barrier film on the surface of hydrocarbon liquids to suppress vaporisation therefrom comprises a fluorocarbon surfactant which contains a water-soluble fluoroaliphatic group and a compatible fluorine free film-promoting surfactant which is water-soluble to at least 0.02% by wt. in water at 25‹C, the composition being free from volatile flammable materials. In this context "compatible" means that the two surfactants do not interact to an inactive product. Specified fluorinated surfactants include C 8 F 17 SO 2 N(C 2 H 5 )C 2 H 4 OPO(OH) 2 ; C 8 F 17 SO 2 N(C 2 H 5 )COOK; C 7 F 15 COOH(CH 3 ) 2 NC 3 H 6 NHC 2 H 4 COOH; and several of the type C 7 F 15 CONHC 3 H 6 N(or N<SP>+</SP>)A. Numerous fluorine-free surfactants are specified. A water-soluble electrolyte, e.g. NaCl or MgSO 4 may also be present, e.g. as in sea water. If required, some of the compositions may be foamed per se by admixture with air or vaporised propellant to form extinguishant compositions. Others form stable foams when mixed with an auxiliary foaming agent, e.g. a hydrolysed protein or a perfluoroaliphatic carbonamido betaine, and/or a foam stabiliser, e.g. a polyoxyethylene glycol or butoxy hydroxyethoxy ethane. Glycerol or ethylene glycol anti-freeze may be added. The foamed compositions are compatible with solid extingishants, e.g. KHCO 3 . Film-forming properties of the compositions of the invention are tested on cyclohexane. The compositions can be used on, e.g. toluene, xylene, gasoline, kerosene and fuel oil. |
