Basf Aktiengesellschaft

Hans-Werner Becker

Heinrich Hartmann

Walter Denzinger

Guenter Hirsch

Michael Ernst Rohmann

Polymers of acrylic acid or methacrylic acid are prepared by polymerizing acrylic acid and/or methacrylic acid at 50.degree.-180.degree. C. in a C.sub.2 -C.sub.6 -alcohol or mixtures thereof with water having a C.sub.2 -C.dwnarw.6.uparw.-alcohol content of not less than 40% by weight in the presence of free radical polymerization initiators and from 0.01 to 5% by weight, based on the monomers used, of inorganic acids of phosphorus in which the phosphorus has an oxidation number of from 1 to 4, or of water-soluble salts thereof, water-soluble --PO(OH).sub.2 -containing compounds and/or water-soluble salts thereof. The polymers thus prepared are effective milling aids and dispersants for pigments for producing aqueous pigment slurries for use in paper-coating compositions.

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Ludwigshafen, Germany

Hans-Werner Becker