Abstract: The present invention relates to a dispersion at least comprising particles comprising at least one magnetic iron oxide as component A and a solvent mixture as component B comprising (B1) 5% to 95% by weight of at least one water-miscible organic solvent LM as component B1 and (B2) 5% to 95% by weight of water as component B2, the sum of components B1 and B2 making 100% by weight, and to a method for producing a dispersion of this kind, comprising at least the steps (I) mixing particles comprising at least one magnetic iron oxide with at least one water-miscible organic solvent LM and water, (II) homogenizing the mixture from step (I), where a shearing energy of at least 2 kW/m3 is introduced into the mixture in step (II).

Abstract: Aqueous polyurethane dispersions contain, at a pH of the dispersing medium of .gtoreq.6, an anionically stabilized polyurethane present in disperse form as well as an added polymer having acidic functions and intended for reducing the flow resistance.

Abstract: A process for reducing the pH of anionic polyurethane dispersions which are stabilized by carboxylate or sulfonate groups, which comprises adding a compound which has from one to four ester groups but no acid group or acid halide or anhydride group to the dispersions.

Abstract: Aqueous dispersions containing a polyurethane and from 5 to 60% by weight, based on the polyurethane, of an adhesion-improving polymer, the polyurethane consisting essentially of(a) organic diisocyanates,(b) dihydroxy compounds which have a molecular weight of from more than 500 to 5,000 g/mol and contain no ionic groups or groups convertible into ionic groups,(c) compounds having one or two functional groups reactive toward isocyanate and at least one ionic group or group convertible into an ionic group and(d) compounds having at last 3 isocyante groups or at least 3 functional groups reactive toward isocyanate,(e) optionally compounds which differ from (c) and have two functional groups reactive toward isocyanate and a molecular weight of from 60 to 500 g/mol, the compounds (d) being used in amounts such that the functionality F of all components is from 2.01 to 2.5, and the polyurethane or a prepolymer thereof is prepared in a water-miscible solvent boiling below 100.degree. C.

Abstract: Aqueous dispersions containA) from 96.95 to 45% by weight of a polyurethane,B) from 3.0 to 50% by weight of a phenol/formaldehyde condensation resin or of an epoxy resin andC) from 0.05 to 5.0% by weight of an inorganic salt having a solubility of less than 1 g/l in water at 20.degree. C.,the percentages by weight being based on the sum of the components A), B) and C).