Лако-красочные материалы — производство

The first commercially successful synthetic pearlescent pigments were hexagonal lead salt crystals, especially basic lead carbonate Pb(OH)2 x 2 PbCO3. Basic lead carbonate is precipitated from aqueous lead acetate with carbon dioxide under carefully controlled reaction conditions. The resulting platelets are less than 0.05 pm thick and show hexagonal dimensions of about 20 pm, yielding […]

7.2.2.1 Natural Pearl Essence Natural pearl essence is isolated as a silky lustrous suspension from fish scales. The pigment particles in the suspension are platelet shaped with a very high aspect ratio (0.05 pm x 1-10 pm x 20-50 pm), and consist of 75-97% guanine and 3-25% hypoxanthine [4, 6-8]. To date there is no […]

The physical background of optical interference effects has been the subject of many publications [3-8, 43, 44]. The optical principles of pearlescent (interfer­ence) pigments are shown in Figure 7.2 for a simplified case of nearly normal incidence without multiple reflection and absorption. At the interface P1 between Figure 7.2 Simplified diagram showing nearly normal incidence […]

The use of pearls and nacreous shells for decorative purposes goes back to ancient times (e. g., in Chinese wood intarsia). The history of pearl pigments dates back to 1656, when the French rosary maker Jaquin isolated a silky lustrous suspension from fish scales (pearl essence) and applied this to small beads to create artificial […]

Gerhard Pfaff 7.1 Introduction Special effect pigments with the most important types, pearl luster and interfer­ence pigments, are based on natural or synthetic materials. They show outstand­ing qualities of luster, brilliance, and iridescent color effects based upon optically thin layers. This visual impression develops by reflection and scattering of light on thin multiple layers. In […]

Modern microscopic and surface analysis techniques can be used to get a better understanding of the pigment particles. In the case of a host pigment lattice such as the DR pigments, there is the question about the uniformity of the dopants throughout the particles. Some preliminary studies on some DR pigments indi­cate that the homogeneity […]

It is extremely important to realize that weathering involves multiple degradation mechanisms. These can be free radical mechanisms (photolytically or thermally induced), or acid or base-catalyzed chemistry, as well as physically based mecha­nisms. This makes weathering a difficult property to study. Second, in general, inorganic pigments do not weather (degrade). It is the poly­mer systems […]

pH values are typically made using 10% pigment slurries in degassed distilled water (ASTM D1208 Procedure 6.1.1). Addition of a small, controlled amount of salt (e. g. reagent grade KCl) improves the electrode response. A blank should be run to verify proper degassing and technique. CO2 absorption decreases the pH. In the absence of better […]

A more recent development is that of non-dusting, free-flowing pigments. Because of their highly cohesive nature, DR pigments have not presented much of a dusting problem, and dust collection systems are typically present in major plants. However, free-flowing powders facilitate the handling of these powders and are finding increasing applications. Currently, some free-flowing DR powders […]

Specific gravities (SG) have historically been reported on pigment data sheets along with two derived values, solid weight and bulking value. Solid weight is sim­ply the SG measured in different units (lbs/gal). Bulking value is simply the recip­rocal of solid weight. These values are for completely densified materials and have no relation to the powder […]