Process for the preparation of aqueous dispersion polymers

A process for flocculating and settling suspended matter from an aqueous solution comprising:

• a) adding to an aqueous solution containing suspended matter an aqueous polymeric dispersion comprising:
• 1) a brine dispersible copolymer comprising from about 10 to about 50 mole percent of a monomer having the formula (II) ##STR9## wherein R.sub.4 is H or CH.sub.3 ;
• R.sub.5 and R.sub.6 are alkyl groups having 1 to 3 carbon atoms;
• R.sub.7 is H or an alkyl group having 1 to 3 carbon atoms;
• A.sub.2 is an oxygen atom or NH;
• B.sub.2 is an alkylene group having 2 to 4 carbon atoms or a hydroxypropylene group, and X.sub.2.sup.- is an anionic counterion;
• from about 1 to about 50 mole percent N-alkylacrylamide, N,N-dialkylacrylamide or mixtures thereof having the formula (III):
• ##STR10## where R.sub.8 is H or CH.sub.3 ;
• and R.sub.9 and R.sub.10 are H or an alkyl group having 1 to 5 carbon atoms, with the proviso that R.sub.9 and R.sub.10 are not both H;
• from about 1 to about 70 mole percent (meth)acrylamide;
• and
• optionally up to about 4 mole percent of a monomer having a formula (I) ##STR11## where R.sub.1 is H or CH.sub.3 ;
• R.sub.2 and R.sub.3 are each an alkyl group having 1 to 3 carbon atoms;
• A.sub.1 is an oxygen atom or NH;
• B.sub.1 is an alkylene group having 2 to 4 carbon atoms or a hydroxypropylene group;
• and X.sub.1.sup.- is an anionic counterion;
• 2) water;
• 3) a multivalent salt;
• 4) a water soluble cationic polymer insoluble in an aqueous solution of said multivalent salt;
• and
• 5) a water soluble cationic polymer soluble in an aqueous solution of said multivalent salt.
• b) allowing said brine dispersible copolymer to coagulate and agglomerate said matter to form a floc.