Titanium dioxide pigment particles and process of producing same

Dry titanium dioxide pigment particles of improved dispersibility, having at least partly adsorbed on the particles from 0,01% to 3% by weight of a non-ionic water-soluble p polyhydric alcohol containing from 4 to 10 carbon atoms, may be prepared by depositing the alcohol on the particles from water or organic solution, for example by slurrying and drying the slurry. Alternatively the particles may be mixed with the alcohol and introduced as a jet into a stream of superheated steam moving at supersonic velocity, whereby the alcohol is uniformly distributed. Suitable polyhydric alcohols include the fully reduced sugar alcohols, which contain one hydroxyl group for each carbon atom in the molecule, although polyhydric alcohols wherein at least half of the carbon atoms carry one hydroxyl group each. Also suitable are those polyhydric alcohols wherein the non-quaternary carbon atoms carry one hydroxyl group each. Mannitol, sorbitol, fructose, dextrose, lerulose, pentaerythritol, anhydroenneaheptetol, invert sugar (a -D-glucopyranose+b -D-fructofuranose), and 2-methyl1,2,3-propanetriol, are specified. The titanium dioxide pigment may in addition contain small amounts of alkali metal and alkaline earth metal salts as conditioning agents, salts of other metals such as antimony, chromium, and zinc, as brighteners and nitile promoters, and the hydrous oxides of aluminium, titanium, zirconium, silicon, and similar elements as agents improving the colour and chalk resistant values of the pigment. Extenders, for example calcium sulphate, barrium sulphate, or lithopone, may also be present.