Production of readily dispersible titanium dioxide pigments

US4235768A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Helmut Ritter · Wuppertal, DE
• Heinz-Peter Hemmerich
• Hans J. Rosenkranz · Krefeld, DE

Key dates

• Filing date: Aug 28, 1979
• Grant date: Nov 25, 1980
• Expiry date: Aug 28, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2004/84
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

In the homogeneous coating of a titanium dioxide pigment with an organic polymer in which an aqueous solution of a polymer containing carboxyl groups is added to a dispersion of titanium dioxide in water, the polymer is applied to the pigment, the coated pigment is separated off from the aqueous medium, washed, dried and, optionally ground, the improvement which comprises employing as the polymer a polymer of the formula ##STR1## in which R.sub.1 each independently is hydrogen or methyl, PA1 R.sub.2 is hydrogen, or alkyl or cycloalkyl containing from 1 to 8 carbon atoms, PA1 M is sodium or potassium, PA1 R.sub.3 is hydrogen, alkyl or cycloalkyl containing from 1 to 12 carbon atoms, or hydroxyalkyl containing from 2 to 6 carbon atoms, PA1 m=0.2 to 1.5, and PA1 n=0 to 0.5, the polymer being added to the titanium dioxide dispersion in the form of a weakly alkaline aqueous solution in about 0.05 to 2.5% by weight based on the titanium dioxide.