| 摘要 |
<p>Multilayer interference pigments with a blue body color comprise a flaky base material (BM) coated with: (1) colorless, transparent metal oxide with high refractive index (RI), (2) colorless, transparent metal oxide with a low RI, and (3) a layer of cobalt aluminate, cobalt glass or cobalt oxide, in the layer sequence (1,2,3,) (IP1) or vice versa (3,2,1) (IP2). Independent claims are also included for the following: (a) a process for the production of layer sequence IP1 by: (i) suspending BM in water and heating to 50-100 degrees C, adding a water-soluble metal compound at a pH suitable for hydrolysis so that a metal oxide hydrate with a high RI is precipitated on the particles of BM (keeping a constant pH by simultaneous addition of acid or base), (ii) adjusting to pH 4-10 with base and precipitating metal oxide hydrate with a low RI by adding a water-soluble metal compound (keeping a constant pH as above), (iii) washing the product, drying at 160-180 degrees C and calcinating at 500-1100 degrees C, (iv) suspending the product in water and coating it at a constant pH of 3-10 with cobalt and aluminum oxide hydrate by addition of suitable water-soluble compounds (plus acid or base) and (v) washing, drying and calcinating as in (iii). (b) A process for the production of IP2 which involves: (1) coating the BM suspension at pH of 3-10 with cobalt (Co) and aluminum oxide hydrate by addition of suitable water-soluble compounds (plus acid or base); (2) adjusting to pH 4-10 with base and precipitating metal oxide hydrate with a low RI by adding a water-soluble metal compound (keeping a constant pH as above), (3) suspending BM in water and heating to 50-100 degrees C, adding a water-soluble metal compound at a pH suitable for hydrolysis so that a metal oxide hydrate with a high RI is precipitated on the particles of BM (keeping a constant pH by simultaneous addition of acid or base), (4) washing, drying at 160 degrees C and calcinating at 500-2200 degrees C. (c) Paint, printing ink, plastics, cosmetics, ceramics and glass, pigmented with pigments (IP1, IP2), especially pigmented laser-markable plastics.</p> |
