Coated titanium dioxide pigment and a process for the production of the same
AssigneeKemira Oy
InventorPekka I. Makinen
Life of this patent
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Abstract
The dispersability of a titanium dioxide pigment is improved by coating it with an organic coating and also an inorganic coating in a total amount of, expressed as oxide, not more than 0.5% and no less than 0.3% of the weight of the pigment. Suitable inorganic coatings are oxides and hydroxides of aluminium, zinc, titanium, zirconium and magnesium.
Claims7
A titanium dioxide pigment, comprising a coating of an inorganic substance, the total amount of the inorganic coating, expressed as oxide, being at maximum about 0.5% of the weight of the pigment and further comprising a coating of an organic substance selected from the group comprising large-molecule fatty acids and their salts;
- organic silicon compounds, such as dimethyl polysiloxane;
- alcohols and polyalcohols.
A process for coating a titanium dioxide pigment to improve its dispersability comprising adding to an aqueous slurry of calcinated titanium dioxide pigment an inorganic water-soluble compound or an inorganic compound which can be brought to a water-soluble form in the slurry, the inorganic compound being added to the titanium dioxide pigment slurry in an amount which, expressed as an oxide, is about 0.05-0.5% of the weight of the titanium dioxide pigment;
- and by depositing it on the titanium dioxide pigment, and further comprising adding to said pigment slurry an organic substance selected from the group comprising large-molecule fatty acids and their salts;
- organic silicon compounds, such as dimethyl polysiloxane;
- alcohols and polyalcohols.
Dependencies are inferred from the claim text.