Patent ID: 7780777

Claim:
A process for the preparation of an aqueous dispersion, said process comprising: placing an aggregated titanium dioxide powder, corresponding to a desired amount in the dispersion, at least one amino alcohol and at least one carboxylic acid are placed in water, producing a pre-dispersion by introduction of energy in an amount of less than 1000 kJ/m 3 , dividing the pre-dispersion into at least two partial streams, placing said partial streams under a pressure of at least 500 bar in a high-energy mill, venting said partials streams via a nozzle, allowing said partial streams to come together in a gas-or liquid-filled reaction space, and optionally adding a preservative; wherein said aggregated titanium dioxide powder has a specific surface area of from 20 to 150 m 2 /g and is added in such an amount that the desired dispersion comprises at least 20 wt. % titanium dioxide, wherein said at least one amino alcohol has from 1 to 6 carbon atoms, wherein said at least one carboxylic acid is selected from the group consisting of a dibasic carboxylic acid having from 2 to 6 carbon atoms, a hydroxycarboxylic acid having from 2 to 6 carbon atoms, and mixtures thereof, wherein, in said dispersion, the aggregated titanium dioxide powder has a mean, volume-related aggregate diameter of less than 150 nm, wherein said dispersion comprises the amino alcohol in an amount of from 2.5 to 7.0 μmol/m 2 of specific surface area TiO 2 , and wherein said dispersion comprises the carboxylic acid in an amount of from 1.0 to 3.5 μmol/m 2 of specific surface area TiO 2 .