Bayer Aktiengesellschaft

Heribert Stutgens

Peter Woditsch

Eckhard Bayer

Peter Panek

Klaus Kohler

Klaus Nollen

Hans Sander

The production of titanium dioxide pigments with improved chalking resistance and gloss retention by coating with an oxide and/or phosphate of zirconium and of titanium, aluminum and/or silicon, the improvement which comprises coating with zirconium by adding to an aqueous alkaline suspension of the titanium dioxide pigment of alkali metal or ammonium zirconium carbonate complex and slowly precipitating the zirconium by adding a dissolved compound of at least one of titanium, aluminum, silicon and phosphorus.

Process for the production of titanium dioxide pigments with high

An inorganic pigment exhibiting improved gloss and distribution in lacquer binders, carrying a coating comprising a polyhydrogen siloxane and an alkanolamine. Advantageously the alkanolamine comprises at least one of triethanolamine, triisopropanolamine, diethanolamine, diisopropanolamine and 2-amino-2-methyl-propanol-1, the polyhydrogen siloxane is a polymethylhydrogen siloxane having more than 5 Si atoms, and the pigment comprises TiO.sub.2 or a titanate carrying an inorganic coating, the polyhydrogen siloxane plus alkanolamine ranging from about 0.3 to 1% by weight of the pigment and the ratio by weight of the polyhydrogen siloxane to alkanolamine ranging from about 1:2 to 1:5.

Inorganic pigments with improved gloss and distribution in lacquer

An inorganic pigment exhibiting improved gloss and distribution in lacquer binders, carrying a coating comprising a SiOH-containing organosilicon compound and an alkanolamine. Advantageously the alkanolamine comprises at least one of triethanolamine, triisopropanolamine, diethanolamine, diisopropanolamine and 2-amino-2-methyl-propanol-1, the organosilicon compound is of the formula ##STR1## wherein n&gt;3, R and R.sup.1 each independently is alkyl, cycloalkyl, aryl, alkenyl or a group of the formula ##STR2## wherein m&gt;1, the organosilicon compound having an OH:Si ratio within the range of about 1:1 to 1:20, and the pigment comprises TiO.sub.2 or a titanate carrying an inorganic coating, the organosilicon compound plus alkanolamine ranging from about 0.3 to 1% by weight of the organosilicon compound to alkanolamine ranging from about 1:2 to 1:5.

Inorganic pigments with improved gloss and good distribution in lacquer

A process for the production of a light-stable and weather-stable titanium dioxide pigment comprising precipitating onto the pigment in aqueous suspension a colorless vanadate of at least one of zinc, magnesium, calcium, strontium and barium at a pH-value above 7 in about 0.01 to 5% by weight, expressed as V.sub.2 O.sub.5, based on TiO.sub.2. Advantageously the pigment either before or after precipitation of the vanadate is coated with at least one oxide, oxide hydrate or phosphate of titanium, silicon, aluminum or zirconium.

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Krefeld, Germany

Heribert Stutgens