Basf Aktiengesellschaft

Walter Machtle

Klemens Mathauer

Graham E McKee

Joachim Pakusch

Bernhard Schuler

Roland Baumstark

Burkhardt Dames

Hubertus Kroner

Emulsion polymerization process with combination macroemulsion and

A process for preparing aqueous polymer dispersions by emulsion polymerization of free-radically polymerizable compounds (monomers) comprises adding, during the polymerization of the monomers, a miniemulsion which is an aqueous, surfactant-stabilized emulsion of monomers whose emulsified droplets have a size of from 10 to 500 nm and which comprises a compound (stabilizer) which is dissolved in the monomers of the droplets and whose solubility in the monomers is at least twice its solubility in water.

Preparation of aqueous polymer dispersions with a bimodal particle-size

Polymers composed of at least &gt;80% by weight of monomers of the formula ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are each C.sub.1 -C.sub.3 -alkyl, R.sup.4 is C.sub.1 -C.sub.5 -alkyl and X is 0 or NH, are used as assistants in the drying of aqueous polymer dispersions and, in the case of a weight average relative molecular weight of from 5000 to 35,000, additionally as protective colloid for the preparation of aqueous polymer dispersions by the free radical aqueous emulsion polymerization method.

Use of polymers as assistants in the drying of aqueous polymer

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Ludwigshafen, Germany

Walter Machtle