WATER-SOLUBLE CROSS-LINKABLE PROTECTIVE COLLOIDS, METHOD OF PREPARING AQUEOUS DISPERSIONS OF POLYMERS STABILIZED BY PROTECTIVE COLLOIDS, AQUEOUS POLYMER DISPERSIONS, AND POLYMER POWDER COMPOSITIONS SUITABLE FOR REDISPERSING IN WATER

摘要

FIELD: polymer materials. SUBSTANCE: water-soluble cross-linkable protective colloids have molecular weight at least 500000 and contain: (i) at least 20% of monomer units containing sulfate or sulfonate groups; (ii) 4-80 % of monomer units containing N-methylol or N- alkoxymethylol groups; (iii) 0.1-20% of hydrophobic monomer units selected from water-insoluble ethylenically unsaturated compounds and hydrophobic terminal groups of initiators or regulatory molecules, all percentages being based on the total copolymer weight. A part of sulfate/sulfonate monomer units in amounts up to 50%, if necessary, can be substituted by carboxy- or amide-containing monomer units. Polymer dispersions are prepared by radical polymerization of ethylenically unsaturated monomers utilizing suspension or emulsion polymerization technique in presence of at least one cross-linkable protective colloid. Aqueous polymer dispersions as well as polymer powder compositions suitable for redispersing in water are useful as binding agents for coatings, plasterwork, and varnish-and-paint materials, as sizing and binding substances in papermaking and textile production, as concrete additives, etc. EFFECT: improved consumer's quality and optimized preparation procedure. 11 cl, 1 tbl, 8 ex