Organic dispersion polymers based on ethylenically unsaturated monomers which contain water-solube graft polymers containing vinyl alcohol units having a polyurethane grafting base, processes for their preparation and their use

摘要

Organic dispersion polymers based on ethylenically unsaturated, polymerizable or copolymerizable monomers which are prepared in the presence of protective colloids or of protective colloids and emulsifiers by emulsion, suspension or bead polymerization or copolymerization, initiated by free radicals, in an aqueous medium and are present in aqueous dispersion form or in finely dispersed dry powder form and which contain, as protective colloids, preferably 0.01 to 20% by weight, based on the dispersion polymer, of water-soluble graft polymers containing vinyl alcohol units on a polyurethane grafting base, the polyurethane grafting bases containing at least 2 urethane groups in the molecule and units of diisocyanates and if appropriate small amounts of monofunctional isocyanates, as well as units of diols and/or half-esterified or half- etherified diol radicals, and polymer radicals or polymeric chains comprising units of carboxylic acid vinyl esters having 3 to 20 carbon atoms and/or hydrolysis products thereof and if appropriate units of other ethylenically unsaturated, polymerizable and if appropriate hydrolyzable and if appropriate copolymerized monomers and/or hydrolysis products thereof being grafted onto the polyurethane grafting bases, the amount of vinyl alcohol units in the water-soluble graft polymers being at least 20% by weight, based on the water-soluble graft polymer, and the degree of hydrolysis of the monomer units originally grafted onto the polyurethane grafting base being at least 50 mol %.