Manufacturing process of mixed metal oxide pigments
Rutile and spinel pigments are produced in a solid-state reaction of fine-particle metal oxides, hydroxides or carbonates in the solid state at temperatures of 800 to 1200°C. The firing process takes place either continuously in rotary kilns or tunnel kilns or discontinuously in direct-fired bogie hearth furnaces or drum furnaces. After annealing, grinding takes place to guarantee the desired colouristic properties as well as easy processing at the end user.
Application paints
Rutile pigments
Compared with iron oxides, rutile pigments offer the advantage of broader colouristic possibilities due to somewhat purer shades. Rutile pigments are characterized by insolubility in water and organic solvents, highest chemical and thermal resistance and excellent light and weather fastness. They are particularly suitable for use in air-drying systems and stove enamels, as well as for coil coating and powder coatings. Another field of application is waterborne and solventborne facade paints.
In combination with high-quality organic yellow and red shades, these products can be used to realise a wide range of colour shades. Here, the rutile pigments provide the necessary hiding power, while the combination with organic pigments enables the required brilliance.
Spinel pigments
The fastness properties of the cobalt pigments to be assigned to the spinel type are excellent. Particularly noteworthy is the excellent chemical resistance as well as the excellent weather fastness, even in strong reductions by means of titanium dioxide. In light pastel shades, they are superior to the well-known organic blue and green pigments. Fields of application are e.g. coil coating, powder coatings, swimming pool coatings / films.
Application construction
Due to their high light, weather and alkali resistance, mixed metal oxide pigments are predestined for use in the construction sector. In the field of plasters, nickel titanates in particular have become established due to their brilliant shade, even with smaller application quantities. For the colouring of blue joint compounds, paving stones and plasters, only cobalt blue pigments are recommended without restrictions. Unfortunately, a comparatively high product price often prevents their use on a larger scale.
