Лако-красочные материалы — производство

5.3.2.1 Definition Metal effect pigments are flake-shaped metallic particles supplied in the form ofpow — ders, pastes, pellets, suspensions or color concentrates [5.166-5.168]. Typical metal effect pigments include aluminum (“silver bronze”) and copper — and copper/zinc — alloys (“gold bronze”). Besides the metal effect pigments there are also metallic pigments and powders for functional coatings […]

Optical coatings that shift color with viewing angle have been adapted into optically variable films, pigments, and inks during recent years [5.125, 5.130, 5.159]. These coatings are based frequently on metal-dielectric multilayer thin structures having large color shifts with angle, high chroma, a large color gamut, and light fastness. Different colors are produced by precisely […]

Metal effect pigments consisting of flakes or lamellae of aluminum (aluminum bronzes), copper and copper-zinc alloys (“gold bronzes”), zinc, and other metals have been well known for a long time [5.157]. Some of these metal flakes, especially aluminum platelets, can be coated with iron oxide in a CVD process [5.126, 5.133, 5.140]. These are commercially […]

Special effect pigments with neutral body color, high luster and improved sparkling properties can be achieved from borosilicate flake substrates (glass flakes) [5.153, 5.154]. These pigments consist mostly of calcium-aluminum borosilicate platelets coated with metal oxide layers such as SiO2, ТЮ2 or Fe2O3. The synthetically man­ufactured flakes can be absolutely planar and show a smooth […]

Thin hexagonal monocrystalline Al2O3 flakes can be produced by hydrothermal pro­cesses [5.150-5.152]. The thickness of the resulting flakes is not uniform. Therefore, the resulting coated pigments merely assume a dull pearlescence. Al2O3 flakes of a higher quality are produced by the following steps (Figure 5.26). An aqueous solution of an aluminum salt is mixed with […]

Instead of mica, SiO2 flakes can be used as a substrate for special effect pigments. The SiO2 flakes are produced by a web-coating process. Synthetic SiO2 flakes offer three advantages over the use of natural mica: 1. The thickness of the SiO2 substrate can be controlled in the preparation so that a pigment with a […]

Simple blending of transparent absorption pigments with pearl luster pigments is only one way to attain new coloristic effects. It is possible to produce pearl lus­ter pigments coated with a layer of transparent absorption colorant to realize more pronounced brilliant colors with a sharper color flop. An additional advantage of such pigments is the elimination […]

The dominant class of pearl luster pigments is based on platelets of natural mica coated with thin films of transparent metal oxides [5.122-5.125, 5.127-5.130, 5.137]. The mica substrate acts as a template for the synthesis and as a mechanical support for the deposited thin optical layers of the pearl luster pigments. Mica minerals are sheet […]

Titanium dioxide flakes can be produced by breaking down a continuous film of TiO2 [5.130, 5.134]. The most efficient process is a web-coating process involving thermal hydrolysis of TiOCl2 on the web. Alternative procedures are the application of titanium alkoxide onto a smooth flat surface and cracking the resulting film into flakes by steam treatment […]

Micaceous iron oxide consists of pure or doped hematite (a-Fe2O3). Its density is 4.6-4.8 g cm-3. Micaceous iron oxide can also be obtained by hydrothermal synthesis in alkaline media. However, the dull dark color is as unappealing as that of the natural product. If substantial amounts of dopants are incorporated, the aspect ratio can be […]