| 摘要 |
An oven-cleaning composition comprises, based on the water present, (i) ammonia or an ammonium compound in an amount 0.1-10% by weight, (ii) an alkali metal alkaline compound in an amount 0.5-15% by weight, (iii) an aliphatic halohydrocarbon solvent in an amount 25-100% by volume, (iv) water. The composition may consist solely of constituents (i)-(iv) or may also contain a surfactant (v). Starch may also be present. Ammonia may be present as ammonia water or as any of the following ammonium compounds:-acetate, bromide, carbonate, chloride, formate, iodide, oxalate, sulphate, or complex ammonium salts: (ammonium) aluminium chloride or sulphate, cadmium chloride, calcium phosphate, chromium sulphate, magnesium carbonate. The alkali metal alkaline compound (ii) is Li, Na or K hydroxide, oxide or lower (C1-C6) alkoxide; silicate in which the alkali metal oxide-silica ratio is 0.5-2:1, e.g. a di-, ortho-, sesqui-, or meta-silicate; phosphate or metapolyphosphate or phosphate "glass";mixed phosphate and silicate, or borate. Component (iii) is preferably a chloro- or bromo-hydrocarbon, e.g. dichloromethane, (methylene chloride), and 1,1,1-trichloroethane, chloroform, carbon tetrachloride, 1,2-dichloroethylene, 1:2-dibromoethane or mixtures thereof; equal volumes of water and halo-hydrocarbon are preferred. Surfactants (v) specified are the sodium salt of the sulphated reaction product of tridecyl alcohol and 3 molecules ethylene oxide, and the sodium salt of sulphonated dodecylated diphenyl oxide. Paraffin or a similar wax, e.g. one melting between 100 DEG and 150 DEG F. (38-65 DEG C.) may be added to inhibit evaporation of the organic solvent. The pH of the composition is usually above 9. The composition may be used in liquid, paste or aerosol form.
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