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AssigneeWacker Chemie AG
InventorsTheo Mayer, Hans-Peter Weitzel, Reinhard Haerzschel, Thomas Bastelberger
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A method for producing protective-colloid-stabilized polymers in the form of their aqueous polymer dispersions or in the form of powders which can be re-dispersed in water, wherein one or several monomers from the group made up of vinyl aromatics, 1.3 dienes, acrylic acid esters and methacrylic acid esters of alcohols with 1 to 15 C-atoms are polymerized in the presence of a combination of protective colloids consisting of one or several protective colloids from the group of hydrophobically modified, partly saponified polyvinyl esters which produce a surface tension of ≦40 mN/m as a 2% aqueous solution, and one or several protective colloids which produce a surface tension of >40 mN/m as a 2% aqueous solution.
A process for preparing protective-colloid-stabilized polymers in the form of their aqueous polymer dispersions or of their water-redispersible powders by emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of protective colloid and, optionally, drying the resultant polymer dispersions, which comprises polymerizing one or more monomers selected from the group consisting of vinylaromatic compounds, 1,3-dienes and acrylates and methacrylates of alcohols having from 1 to 15 carbon atoms in the presence of a protective colloid combination made from one or more protective colloids selected from the group consisting of hydrophobically modified, partially hydrolyzed polyvinyl esters which as 2% strength aqueous solution produce a surface tension of ≦40 mN/m, and made from one or more protective colloids which as 2% strength aqueous solution produce a surface tension of >40 mN/m.
Dependencies are inferred from the claim text.