PROCESS FOR PRODUCING POWDERY POLYMERS BASED ON N-VINYL CAPROLACTAMS

摘要

Powdery polymers based on n-vinyl caprolactams are produced by polymerising (A) 50 to 100 % by weight N-vinyl caprolactams with (B) 0 to 50 % by weight other N-vinyl lactams, vinyl heteroaromatics, vinyl esters, C1 to C10 alkyl acrylates or methacrylates or a mixture thereof and (C) 0 to 5 % by weight monoethylenically unsaturated monomers containing acid groups. For that purpose, (i) the monomers A, B and C are polymerised in a homogenous aqueous solution that contains 10 to 95 % by weight, in relation to the water, of a water-miscible organic solvent, or in a homogeneous mixture of 0 to 90 % by weight water and 100 to 10 % by weight methanol in the presence of a radical-forming initiator, and water is then substituted for the organic solvent; or (ii) the monomers A, B and C are polymerised in an aqueous emulsion in the presence of a radical-forming initiator and if required in the presence of an emulsifier. The thus obtained aqueous polymer solutions or dispersions are subjected to a usual drying process to produce powdery polymers.