Basf Aktiengesellschaft

Mario Sandor

Joachim Pakusch

Hans-J&uuml;rgen Denu

Rolf Gulden

Bernd Reck

Cheng-Le Zhao

Claudia Wood

Uwe Dittrich

Heinrich Sack

Wolfgang H&uuml;mmer

Stefan Dreher

Harald R&ouml;ckel

Markus Koppers

An aqueous polymer dispersion having a minimum film-forming temperature of below &plus;65&deg; C. comprising at least one film-forming polymer in the form of dispersed polymer particles comprising a polymer phase P1 and a different polymer phase P2, the polymer dispersion being obtainable by free-radical aqueous emulsion polymerization comprising the following steps: i) polymerization of a first monomer charge M1 to give a polymer P1 having a theoretical glass transition temperature T (according to Fox) and ii) polymerization of a second monomer charge M2 to give a polymer P2 having a theoretical glass transition temperature T (according to Fox) which is different from T in the aqueous dispersion of the polymer P1, at least one chain transfer reagent being used either in the polymerization of the monomer charge M1 or in the polymerization of the monomer charge M2; a process for preparing the aqueous polymer dispersion; and a pigmented and/or filled coating composition comprising as a binder the aqueous polymer dispersion.

Aqueous polymer dispersions

An aqueous polymer dispersion, wherein the dispersion contains from 0.0001 to 1 mol of a hydrolyzable silicon group and from 0.0001 to 1 mol of a urea or thiourea group, based, in each case, on 100 g of the polymer present in the dispersion.

Silane-containing polymer dispersions for tile cements

Cement compositions comprising redispersible polymer powders

The present invention provides a process for preparing polymer powders by evaporating the volatile constituents from aqueous dispersions of film-forming polymers P in the presence of drying assistants T selected from the salts of oligomeric arylsulfonic acid-formaldehyde condensates wherein prior to the evaporation of the volatile constituents the aqueous polymer dispersion comprises at least 1.5% by weight, preferably at least 1.7% by weight, based on the polymer in the dispersion, of at least one anionic surface-active compound AO having at least one C -C alkyl group; the polymer powders obtainable by the process; and their use in binding mineral building materials.

Preparation of polymer powders

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Worms, Germany

Mario Sandor