Process for the preparation of stable water-in-oil emulsions of hydrolyzed polymers of N-vinyl amides and the use thereof

摘要

PCT No. PCT/EP95/01818 Sec. 371 Date Nov. 21, 1996 Sec. 102(e) Date Nov. 21, 1996 PCT Filed May 13, 1995 PCT Pub. No. WO95/32227 PCT Pub. Date Nov. 30, 1995A process for the preparation of a stable water-in-oil emulsion of a hydrolyzed polymer of an N-vinyl amide of the formula (I) in which R and R1 denote H or C1-C6 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 (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 (a) from 5 to 95 wt % of a block or graft copolymer of the structure (A-B)m, (A)nB or (B)nA, in which in each case A is a hydrophobic homopolymer or copolymer having a degree of polymerization of at least 3, B is a hydrophilic homopolymer or copolymer having a degree of polymerization of at least 3, m is equal to or greater than 1, and n is equal to or greater than 2, and (b) from 5 to 95 wt % of another water-in-oil emulsifier having a molar mass below 1000 g/mol.