Wacker Chemie Ag

Wacker Polymer Systems Gmbh & Co. Kg

Stefan Killat

Hans-Peter Weitzel

Hermann Lutz

Peter Fritze

Michael Herbert

Jochen Ring

Bernd Gerstenberger

Marion Killat

Andrea Schorm

The invention provides a process for preparing dispersion powders by spray drying of aqueous polymer dispersions of polymers of one or more ethylenically unsaturated monomers selected from the group encompassing vinyl esters, methacrylic esters, acrylic esters, olefins, dienes, vinylaromatics, and vinyl halides with a drying gas in a nozzle atomization dryer, characterized in that the aqueous polymer dispersion (feed), before being atomized, is preheated under pressure to a temperature of 100&#xb0; C. to 200&#xb0; C. and is atomized at this temperature, the pressure being set such that the aqueous phase of the polymer dispersion does not boil at the temperature selected.

Process for preparing dispersion powders

A process for producing dispersible powders by spray-drying aqueous polymer dispersions and adding antiblocking agent, wherein antiblocking agents present in agglomerated form and having a particle size from 10 &#x3bc;m to 250 &#x3bc;m, or having a particle size from 5 mm to 5 cm in the case of agglomerates in the form of extrudates, are fed in whole or in part by a transport gas into the spray-drying device and are comminuted to a particle size from 0.01 &#x3bc;m to 5 &#x3bc;m, or, in the case of extrudates, to a particle size from 2 &#x3bc;m to 60 &#x3bc;m.

Process for producing dispersible powders

A process for producing dispersion powders by spray drying of aqueous polymer dispersions and addition of antiblocking agents in a rotary atomization dryer, wherein the antiblocking agent is conveyed by delivery air, wholly or partly, into an annular gap which is formed by a moulding arranged concentrically around the housing of the rotary atomizer, and which ends at a distance above the upper edge of the atomizer plate of the rotary atomizer.

Process for producing dispersion powders

Redispersible polymer powders which are cationically stabilized by spray drying a polymer dispersion with a cationic polymer can be used in higher concentrations in chemical building construction materials without introducing adverse properties.

Process for producing cationically stabilized and water-redispersible polymer powder compositions

Water-redispersible polymer powder compositions are obtained by means of free-radical-initiated polymerization in aqueous medium of one or more monomers of vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 15 carbon atoms, methacrylic esters and acrylic esters of alcohols having from 1 to 15 carbon atoms, vinylaromatics, olefins, dienes and vinyl halides and subsequent drying of the polymer dispersion, wherein one or more silanes of the general formula (RO)RSiRX (1) where X is an amino- or epoxy-containing radical are added before drying of the polymer dispersion. The powders are especially useful in tile adhesives for tiles having low water absorbtion capacity.

Silane-modified dispersion powders

Hydrophobicizing additives are water-redispersible powders or aqueous dispersions containing:

Hydrophobicizing additives

Water-redispersible polymer powder compositions based on homopolymers or copolymers of one or more monomers from the group consisting of vinyl esters of unbranched or branched alkylcarboxylic acids having from 1 to 15 carbon atoms, methacrylic esters and acrylic esters of alcohols having from 1 to 15 carbon atoms, vinylaromatics, olefins, dienes and vinyl halides, one or more protective colloids, if desired antiblocking agents, contain one or more compounds from the group of pozzolanas. The pozzolanic compounds preferably take the place of anti-blocking agents conventionally used.

Growing community of inventors

Burghausen, Germany

Stefan Killat