| 摘要 |
1281135 Coated metal surfaces FARBENFABRIEKEN BAYER AG 22 Dec 1970 [30 Dec 1969] 60791/70 Heading B2E [Also in Divisions B3 C1 and C7] A pretreated coated metal surface is protected by a removable layer of a water-soluble polyphosphate prior to shaping and receiving a permanent protective coating. In particular, steel sheets are degreased, pickled, and nickel plated; the water-soluble polyphosphate is applied by immersion or spray; the metal is shaped by rolling, pressing, or drawing, and is then enamelled, with or without prior removal of the polyphosphate layer. Suitable polyphosphates are Na, K, Na/K, Li, NH4, or substituted NH 4 salts of polyphosphonic acids of formula HO(HOPO 2 ) n H in which n is at least 10 and preferably more than 100. To the polyphosphate may be added organic substances having plasticising, film-forming, or emulsifying effects. |
