Лако-красочные материалы — производство

Synthetic iron oxide pigments have become increasingly important due to their pure hue, consistent properties, and tinting strength. Single-component forms are mainly produced with red, yellow, orange, and black colors. Their composition corresponds to that of the minerals hematite, geothite, lepidocrocite, and magnetite. Brown pig­ments usually consist of mixtures of red and/or yellow and/or black; […]

Naturally occurring iron oxides and iron oxide hydroxides were used as pigments in prehistoric times (Altamira cave paintings) [3.3]. The Egyptians, Greeks, and ancient Romans also used them as coloring materials. Hematite (a-Fe2O3) has attained economic importance as a red pigment, geothite (a-FeOOH) as yellow, and the umbers and siennas as brown pigments. Deposits with […]

The continually increasing importance of iron oxide pigments is based on their non­toxicity, chemical stability, wide variety of colors ranging from yellow, orange, red, brown, to black, and good performance/price ratio. Natural and synthetic iron oxide pigments consist of well-defined compounds with known crystal structures (Table 3.1) [3.1, 3.2]. Nevertheless the inconsistency of the CAS-Numbers […]

Transition metals are responsible for color in many inorganic pigments. Metal oxides and oxide hydroxides are particularly important as colored pigments because oftheir optical properties, low price, and ready availability. Colored pigments based on oxides and oxide hydroxides are either composed of a single component or mixed phases. 3.1.1

Colored pigments differ from black and white pigments in that their absorption and scattering coefficients are wavelength dependent with widely varying absolute values. The dependence of these coefficients on wavelength, particle size, particle shape, and their distributions determine the color, and hiding power of the pigments (see Section 1.3.1). 3.1

The EC50 value for ZnO (Selenastrum capricornicum 72 h) was determined to be 170 pg L-1. In consequence zinc oxide is classified as dangerous for the environment (EU Classification 67/548/EEC, 29ATP 2004) with the Risk Phrases R50/53 (Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.

Zinc is not considered to be toxic or dangerous. It is an essential element for humans, animals and plants [2.85]. The human body contains ca. 2 g of zinc and a daily intake of 15 mg for humans is recommended. The oral LD50 value for rats is >15,000 mg ZnO kg-1 (OECD 401). Exposure to […]

A yearly market demand of 260,000 t of zinc oxide can be assumed for the EU. The annual world consumption is in the region of 750,000 t, representing ca. 8% of the world zinc metal production. The rubber industry consumes ca. 45% of the total and the remainder is divided among a large number of […]

Zinc oxide has many uses. By far the most important is in the rubber industry. Almost half the world’s ZnO is used as an activator for vulcanization accelerators in natural and synthetic rubber. The reactivity of the ZnO is a function of its specific surface area, but is also influenced by the presence of impurities […]

Many standard specifications have been laid down for the more important uses of ZnO (rubber, paints, and the pharmaceutical industry). For standards, see Table 1.1 (“Zinc oxide pigments; Methods of analysis” and “Specification”). Various methods of classification are used, often based on the production process and the chemical composition. The most well known are pharmacopeias […]