Patent GB-801411-A (GB)
Title: Improvements in the properties of aqueous emulsions and dispersions
IPC: C09K23/00
Filed: 1956-06-27
Abstract: The properties of water-containing dispersions or emulsions of substances which are not polymerizable and not miscible with water are improved by adding thereto a polymerizable ethylenically unsaturated carboxylic acid amide which is then polymerized. Unsaturated amides specified are acrylamide, methacrylamide, N-ethyl- and N,N-diethyl-acrylamide, N-methylolacrylamide and methacrylamide, N-hydroxyethylacrylamide, alpha-chloracrylamide, allylacrylamide, acrylic ureas and fumaric diamide and mixtures thereof; also present during polymerization may be other ethylenically unsaturated compounds such as unsaturated mono- or di-carboxylic acids, e.g. acrylic acid, and their salts, esters and nitriles, unsaturated alcohols and their esters and vinyl ethers, halides and lactams.  The polymerization is carried out with the aid of catalysts such as hydrogen peroxide, potassium persulphate, acetyl peroxide, cyclohexanone hydroperoxide, azo-bis-isobutyronitrile, a potassium persulphate/sodium hydrosulphite redox system or ultra-violet light. The process may be applied to dispersions of waxes, pigments and synthetic resins, e.g. polyamides, urea/aldehyde condensation products, condensation products of polycarboxylic acids, polyalcohols and unsaturated oils and polymers of vinyl esters and ketones, vinyl and vinylidene halides, acrylic and methacrylic esters, N-vinyl compounds and C-vinyl compounds.  In examples: (1) vinyl propionate is polymerized in an aqueous medium containing a methacrylamide/vinyl pyrrolidone copolymer and the reaction product of ethylene oxide and octadecyl alcohol in the presence of potassium persulphate, at the end of polymerization acrylamide is added and heating continued for four hours, after cooling titanium dioxide may be added to the dispersion; (2) a mixture of vinyl propionate vinyl-chloride and butyl acrylate is polymerized in an aqueous medium containing a saponified acrylonitrile/methyl acrylate copolymer and the reaction product of ethylene oxide and octadecyl alcohol in the presence of potassium persulphate, at the end of polymerization methacrylamide and a further quantity of potassium persulphate are added and heating continued for six hours; (3) vinyl propionate is polymerized in an aqueous medium containing polyvinyl alcohol in the presence of potassium persulphate, at the end of polymerization a mixture of acrylamide, methacrylamide and N-methylolmethacrylamide is added, together with azo-bis-isobutyronitrile, and then polymerized; (4) vinyl propionate is polymerized in an aqueous medium containing a vinyl pyrrolidone/methacrylamide copolymer, to the resulting dispersion there is added a mixture of methacrylamide, N-ethylacrylamide and potassium persulphate and heating is continued for six hours; (5) as in (4) but using a mixture of methacrylamide and fumaric diamide and a potassium persulphate/sodium hydrosulphite catalyst mixture; (6) olive oil or montan wax is emulsified in water containing a methacrylamide/vinyl pyrrolidone copolymer and there is added thereto methacrylamide, potassium persulphate and an oleic acid/ethylene oxide reaction product, followed by heating for five hours; (7) as in (6) but in which there is emuslified a condensation product of phthalic acid, glycerine and linseed oil and in which there is added with the methacrylamide an octadecyl alcohol/ethylene oxide reaction product; (8) a mixture of methyl acrylate and vinyl propionate is polymerized in an aqueous medium containing a saponified acrylonitrile/methyl acrylate copolymer in the presence of potassium persulphate, after polymerization there is added a mixture of methacrylamide, acrylic acid and potassium persulphate and heating is continued for four hours.