Лако-красочные материалы — производство

Transparent titanium dioxide exists in both rutile and anatase forms. The average primary particle size (uncoated) ranges from 8 to 25 nm. The specific surface area has values between 80 and 200 m2 g-1.

Typical applications are:

— UV absorbers

— Catalysts (DENOX)

— Effect pigments in coatings

— Gas purification by absorption

— Heat stabilizers for silicone rubber

— Prevention of oxidative degradation of polymers by UV light

— Raw material for ceramic materials

Transparent titanium dioxide can be manufactured by various wet-chemical and gas-phase processes. The properties of the reaction products can vary greatly, depend­ing on the reaction conditions and starting materials. To reduce the high photochem­ical activity of untreated transparent titanium dioxides, the pigments are coated with a variety of inorganic oxide combinations (e. g. of silicon, aluminum and zirconium oxides) [5.195].

The following reactions are used to manufacture transparent titanium dioxides:

— Anatase: hydrolysis

TiOSO4 + H2O ^ TiO2 + H2SO4

— Rutile: hydrolysis

TiOCl2 + H2O ^ TiO2 + 2 HCl

— Rutile/anatase: combustion in an oxyhydrogen flame TiCl4 + 2 H2 + O2 ^ TiO2 + 4 HCl

— Amorphous: hydrolysis of organic titanates Ti(OC3H7)4 + 2 H2O ^ TiO2 + 4 C3H7OH

5.4.3.2