| abstract |
A process for the preparation of a stable water-in-oil emulsion of a hydrolyzed polymer of an N-vinyl amide of the formula ##STR1## in which R and R 1 denote H or C 1 -C 6 alkyl, by the polymerization of a compound of the formula I alone or in admixture with another ethylenically unsaturated monomer in the presence of a polymerization initiator and emulsifier in the form of a water-in-oil emulsion, to form a water-in-oil polymeric emulsion, followed by hydrolysis of the polymer in the form of the water-in-oil polymeric emulsion in the presence of an acid or base and from 1 to 30 wt %, based on the polymer, of an emulsifier, the emulsifier used being a mixture of n (a) from 5 to 95 wt % of a block or graft copolymer of the structure (A-B)m, (A)-B or (B)-A, in which in each case n (a) from 5 to 95 wt % of a block or graft copolymer of the structure (A-B) m , (A) n B or (B) n A, in which in each case n A is a hydrophobic homopolymer or copolymer having a degree of polymerization of at least 3, n B is a hydrophilic homopolymer or copolymer having a degree of polymerization of at least 3, n m is equal to or greater than 1, and n n is equal to or greater than 2, n and n (b) from 5 to 95 wt % of another water-in-oil emulsifier having a molar mass below 1000 g/mol. |