Leicht dispergierbare anorganische Pigmente

A dispersible inorganic pigment carries on the surface thereof a non-ionic cyclic acetal or ketal of a polyhydric alcohol. The pigment may be an oxide of iron or chromium, or TiO2 which may have Al(OH)3, SiO2 or TiO2 precipitated thereon. The pigment may contain 0.05-2% of the surface active agent. The polyhydric alcohol may contain 2-6 OH groups and 2-10 carbon atoms, and the acetal or ketal may be prepared by reacting it with an aliphatic, cycloaliphatic or aromatic aldehyde or ketone. At least 2 of the OH groups of the polyol should react with the carbonyl compound to form one or more rings which may have 5-8 ring members. Unreacted OH groups may be reacted with an aliphatic, unsaturated or aromatic carboxylic acid, or with an alkylene oxide, e.g. as in Specification 1,115,334. The surface active agent may be added in the undiluted form to the pigment, or it may be dissolved or suspended in H2O or an organic liquid and added to the pigment.