method for the discontinuous production of concentrated acrylaatdispersies and application of these dispersions formed voortbregsel produced.

摘要

1,261,672. Acrylic polymers. ROHM G.m.b.H. 2 March, 1970 [1 March, 1969], No. 9917/70. Heading C3P. Aqueous dispersions of acrylic resins are produced by polymerizing or copolymerizing a monomer composition comprising (a) at least one ester of acrylic and/or methacrylic acid; optionally (b) styrene or a homologue thereof; and, optionally (c) one or more other copolymerizable monomers; the combined amount of component (a), and (when present) component (b) in the monomer composition being at least 50% by weight; the said monomer composition being in the form of an aqueous emulsion thereof containing an anionic emulsifying agent; the aqueous emulsion being produced by adding the monomer composition, preferably in the form of an aqueous emulsion additive with the anionic emulsifying agent and part of the water of the final aqueous emulsion, to an appropriate amount of water, if desired, containing an amount of the anionic emulsifying agent, to produce the desired emulsion; the said emulsifying agent being present in the water at the start of the polymerization or copolymerization reaction in a concentration within the range of from 0À3-3À0 times the critical micelle formation concentration (C.M.C.) based on the aqueous phase of the emulsion, the concentration of said emulsifying agent being such that the aqueous dispersion of the synthetic resin obtained has an average particle size and particle size distribution such that upon diluting the dispersion to 10% solids content and centrifuging the diluted dispersion at 10,000 g for 15 minutes at 20‹C. with a maximum free sedimentation path of 43 mm., a sediment amounting to 10 to 80% by weight of the synthetic resin is obtained; and the amount of monomer composition used being selected whereby the aqueous dispersion of the synthetic resin obtained contains at least 55% by weight of the synthetic resin. In the examples, using ammonium persulphate with sodium lauryl sulphate or ethoxylated, sulphated and neutralized alkyl phenol, there are polymerized (1) n-butyl acrylate / acrylonitrile / N-methylol methacrylamide; (2) n-butyl acrylate/methyl methacrylate / N-methylol methacrylamide / methacrylamide/glycol dimethacrylate; (3) n-butyl acrylate/methyl methacrylate; (4) styrene/n-butyl acrylate/methacrylic acid; (5) ethyl acrylate/ methyl methacrylate; (6) methyl methacrylate/ butyl acrylate/acrylic acid.