Patent GB-1071430-A (GB)
Title: Process for the emulsion polymerization of ethylenically unsaturated polymerizable compounds
IPC: C08F2/24
Filed: 1964-11-17
Abstract: In an emulsion polymerization process one or more ethylenically unsaturated monomers are polymerized in the presence of, as emulsifier, a water-soluble curable ether of a polymethylol-melamine or polymethylolurea, in which at least one methylol group is etherified with a monohydric alcohol containing at least 4 carbon atoms and at least one methylol group is etherified with a polyethylene glycol.  Suitable monomers include vinyl esters, ketones and halides; vinyl aryl, e.g. styrene, compounds; esters, nitriles and amides of acrylic, methacrylic, ethacrylic, crotonic, fumaric, maleic and itaconic acids; acrylic and methacrylic acids and salts thereof; olefines; dienes; vinyl heterocyclic compounds; hydrocarbons such as camphene; and vinyl and allyl ethers. The emulsifiers may be obtained by etherifying a polymethylol-melamine or -urea with an alcohol, such as n-butanol, n-amyl alcohol, pentanol-1, hexanol-1, 2-ethylbutanol-1, lauryl alcohol or benzyl alcohol, and reacting the resulting partially etherified product with polyethylene glycol at 80-100 DEG  C. under vacuum, preferably in the presence of a small amount of an acid such as acetic acid.  Suitable polyethylene glycols may have molecular weights from 600 to 20,000, preferably 1000 to 5000. For the polymerization, which is advantageously effected in deionized water, a catalyst is generally used, e.g. peracetic acid, hydrogen peroxide, organic peroxides, percarbonates, persulphates, e.g. potassium or ammonium persulphate, or perborates, if desired together with an activator such as sodium or ammonium bisulphite, sodium thiosulphate or an aliphatic tertiary amine such as triethanolamine or diethyl ethanolamine.  A molecular weight regulator such as a mercaptan or terpene may also be present. Polymerization is preferably effected at a pH of of 6 to 8.  The polymer emulsions so obtained are suitable for the production of films, foils, coatings and impregnates, particularly when a curing agent such as hydrochloric acid, formic acid, p-toluene sulphonic acid, or ammonium thiocyanate, chloride, nitrate or phosphate is added.  Substrates suitable for coating or impregnating include textile materials, leather, paper, wood and metal surfaces.  The polymer emulsions may also be used as binding agents for pigments, e.g. titanium white.  Examples illustrate the preparation of emulsions of (a) polyvinyl acetate, and copolymers of (b) n-butyl acrylate/acrylonitrile, (c) n-butyl acrylate/styrene, (d) ethyl acrylate / acrylonitrile, (e) n - butyl acrylate/acrylonitrile / calcium acrylate, (f) n - butyl acrylate / methylolacrylamide methyl ether/calcium acrylate, (g) n-butyl acrylate/methylolacrylamide/calcium acrylate, (h) vinyl acetate/diethylaminopropyl acrylamide quaternated with chloroacetamide, (i) vinyl acetate/calcium acrylate.ALSO:Aqueous polymer emulsions obtained by polymerising one or more ethylenically unsaturated monomers in the presence, as emulsifier, of a water-soluble curable ether of a polymethylol-melamine or polymethylol-urea, in which at least one methylol group is etherified with a monohydric alcohol containing at least 4 carbon atoms and at least one methylol group is etherified with a polyethylene glycol, are suitable for coating substrates such as textile materials, leather, paper, wood and metal surfaces.  A curing agent may be included in the emulsion, e.g. hydrochloric acid, formic acid, p-toluenesulphonic acid, or ammonium thiocyanate, chloride, nitrate or phosphate, curing being effected by heating, for example, at 120 DEG  to 150 DEG C.  In an Example, an emulsion of n-butyl acrylate/acrylonitrile/calcium acrylate copolymer containing, as emulsifier, polymethylol-urea etherified with n-butanol and polyethylene glycol (molecular weight 1540) and also containing formic acid, ammonium nitrate and titanium white, is applied by brushing or spraying to sheet iron and glass, dried, and stoved at 120 DEG C. to produce water-resistant coatings.