Basf Aktiengesellschaft

Michael Ernst Rohmann

Heinrich Hartmann

Walter Denzinger

Kurt Wendel

Guenter Hirsch

Alfred Muenster

Hans-Werner Becker

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.

Preparation of polymers of acrylic acid or metharcylic acid

An improved process for the production of polymers of acrylic acid or methacrylic acid by polymerizing acrylic acid or methacrylic acid in isopropanol or in a water-isopropanol mixture containing at least 40% by weight of isopropanol in the presence of polymerization initiators at a temperature of from 120.degree. to 200.degree. C. under pressure. The polymers obtained are used as dispersing agents for inorganic pigments.

Manufacture of polymers of acrylic acid or methacrylic acid

Paper coating compositions with finely divided pigment, optical brightener and a binder containing a copolymer of from 5 to 30% by weight of mono-olefinically unsaturated carboxylic acids, from 5 to 30% by weight of mono-olefinically unsaturated monomers containing basic nitrogen atoms and from 50 to 80% by weight of other olefinically unsaturated monomers which, when polymerized alone, give water-insoluble homopolymers and cause virtually no reduction in the effect of conventional optical brighteners even in the absence of casein or carboxymethyl cellulose.

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Bad Duerkheim, Germany

Michael Ernst Rohmann