Chemically-initiated inverse emulsion polymerization with Na, Li/Cl, Br salt
AssigneeHercules Incorporated
InventorDavid C. Zecher
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Abstract
A chemically initiated water-in-oil emulsion polymerization process is disclosed for making water-soluble anionic copolymers from water-soluble, ethylenically unsaturated, addition polymerizable monomers. Improved products are obtained by adding a water-soluble salt to the aqueous phase of the water-in-oil emulsion prior to polymerization.
Claims10
In a chemically initiated water-in-oil emulsion polymerization process for making water-soluble anionic copolymers from at least two water-soluble, ethylenically unsaturated, addition polymerizable monomers, at least one of which is anionic, the improvement comprising:
- adding a salt selected from the group consisting of NaCl, NaBr, LiCl and LiBr to the aqueous phase of the water-in-oil emulsion prior to polymerization, and dispersing the aqueous phase and oil phase whereby the droplet size of the aqueous phase in the resulting emulsion is about 5 microns or less.
In a chemically initiated water-in-oil emulsion polymerization process for making water-soluble anionic copolymers from at least two water-soluble, ethylenically unsaturated, addition polymerizable monomers, at least one of which is an anionic monomer selected from the group consisting of
- (a) monomers conforming to the formula ##STR7## wherein R represents hydrogen or methyl, Y represents --NH.sub.2, --OM, or ##STR8## and wherein M is hydrogen, H.sub.4 N.sup.+, alkali metal, or a cation yielding a water-soluble polymerizable compound, (b) vinyl sulfonic acid, (c) alkali metal salts of vinyl sulfonic acid, (d) diacetone acrylamide, and (e) mixtures thereof, the improvement comprising adding to the emulsion prior to polymerization a water-soluble salt selected from the group consisting of NaCl, NaBr, LiCl, and LiBr, said salt comprising from about 2% by weight, based on the weight of the total emulsion, up to the saturation level of the salt in the aqueous phase of the emulsion at the temperature of polymerization, and the droplet size of the aqueous phase in the emulsion being about 5 microns or less.
Dependencies are inferred from the claim text.