Hoechst Aktiengesellschaft

Werner Stelzel

Helmut Braun

Helmut Rinno

Rolf Reinecke

Hans-Ullrich Huth

Karl J Rauterkus

Josef Mondt

Heinz Lehmann

Erhard Bister

Wolfgang Winstel

Hans Vitzthum

Use of finely divided aqueous cationic dispersions of synthetic resins obtainable by emulsion polymerization from suitable monomers and which contain cationic dispersion polymers, as impregnants and primers for consolidating and priming of porous absorbent substrates, preferably inorganic substrates such as, for example, masonry, concrete, plaster surfaces, gypsum surfaces, bricks or wood, by treating these substrates with the aqueous cationic dispersions whose polymer particles have mean particle diameters of 0.02 to 0.2 .mu.m. Aqueous cationic dispersions of synthetic resins exhibit a superior penetrating and permeating power, in particular on smooth plaster surfaces and smooth gypsum surfaces, compared with aqueous anionic or non-ionic dispersions of synthetic resins. Moreover they have no tendency to foam formation and can, in contrast to aqueous anionic or non-ionic dispersions of synthetic resins, exhibit a sealing action against staining, water-soluble substances, such as tarry products (tobacco smoke), resins, wood constituents (tanning) and dyes, which is of particular advantage for example in the building trade in the renovation of old buildings.

Use of aqueous cationic dispersions of synthetic resins for impregnating

Dispersion paints with high wet adhesion are obtained if, as the binder thereof, an aqueous plastics dispersion is used, the polymer content of which includes monomeric units of an acetoacetic acid ester of an unsaturated alcohol, especially vinyl or allyl alcohol or a diester of a dihydroxy compound in which one acyl radical is acetoacetyl and the other acyl radical is an acrylic or methacrylic radical. The preparation of paints with a low pigment content is especially facilitated by the use of such a dispersion.

Aqueous dispersion paints and process for making the same

Thixotropic mixture

The wet adhesion of plastics dispersions and of paints made therewith is widely improved, if in the manufacture of the dispersions a nucleophilically substitutable .alpha.-.beta.-unsaturated halogen compound in an amount of 0.5 to 10% by weight calculated on the total amount of monomers is copolymerized, and the dispersion so obtained is reacted with ammonia at a temperature of at least 50.degree. C.

Process for the manufacture of plastics dispersions

Absorptive substrates, such as asbestos cement, concrete plaster work, can be impregnated to lock the pores and to consolidate the substrate, especially old and weathered plaster work, with aqueous plastics dispersions, if dispersions are used which have an average particle size of about 0.02 to at most 0.1.mu.m, and preferably from 0.036 to 0.080.mu.m. As opposed to conventional dispersions with larger particle sizes, the penetration of dispersions according to the invention reaches the same values as that of the solvent-based impregnating and priming compositions hitherto used. Aqueous dispersions are easier to handle and permit relatively high solids contents at a moderate viscosity.

Impregnation and primer coating of absorptive substrates with plastics

The wet adhesion of plastics dispersions and of paints made therewith is widely improved, if in the manufacture of the dispersions a glycidyl ester of an olefinically unsaturated carboxylic acid in an amount of 0.5 to 10% by weight calculated on the total amount of monomers is copolymerized, and the dispersion so obtained is reacted with ammonia at a temperature of at least 50.degree. C.

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Bad Soden am Taunus, Germany

Werner Stelzel