| 摘要 |
Prodn of metallic pigments comprises: (A) coating metal platelets with opt. hydrated silica or alumina by hydrolysis of organic Si and/or Al cpds. (where the organic gps. are bonded to the Si and/or Al via O atoms) in soln. in an organic solvent, opt. followed by drying; (B) coating the resulting particles with (i) metal by vapour-phase decomposition. of volatile metal cpds. in an inert atmos., (ii) metal by electroless chemical deposition and opt. drying or (iii) non-selectively absorbing metal oxide by vapour-phase decomposition. of volatile metal cpds. in the presence of O2 and/or steam; and opt. (C) coating the resulting particles with colourless or selectively absorbing metal oxide by (i) vapour-phase decomposition. of volatile metal cpds. in the presence of O2 and/or steam or (ii) hydrolysis of organo metallic cpds. (where the organic gps. are bonded to the metals via O atoms) in soln. in an organic solvent, followed by drying. Also claimed are: (1) metallic pigments obtainable by the above process; (2) metallic pigments comprising Al platelets coated with a 50-600 nm layer of opt. hydrated silica, a 1-25 nm layer of Mo, Cr, W and/or Fe and opt. a 5-520 nm layer of opt. hydrated silica and/or alumina; (3) pigment mixts. comprising the metallic pigments of (1) or (2) and silicate platelets coated with a first layer of colourless or selectively absorbing metal oxide, a second layer of metal and/or non-selectively absorbing metal oxide and opt. a third layer of colourless or selectively absorbing metal oxide; (4) a process for producing the pigment mixts. of (3); and (5) a process for producing silica-coated metal platelets comprising hydrolysing organic Si cpds. (where the organic gps. are bonded to Si via O atoms) in soln. in an organic solvent under acidic or alkaline conditions and drying the prod.
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