Patent GB-1036468-A (GB)
Title: Synthetic polymer emulsions of controlled particle size
IPC: C08F2/22
Filed: 1963-05-29
Abstract: Stable aqueous dispersions of polymers of vinyl chloride, vinylidene chloride, vinyl acetate, methyl methacrylate, ethyl methacrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate or styrene are prepared by polymerizing the monomers, optionally in admixture with up to 30 weight per cent of comonomer, in an aqueous medium initially containing a water-insoluble soap as sole emulsifier and after at least 1% conversion of the monomer to polymer particles adding a water-soluble emulsifier in amount which is either just sufficient to stabilize the existing polymer particles as the polymerization progresses without nucleation or initiation of new particles, or is a controlled excess over such an amount in order to nucleate or initiate a family of new polymer particles, whereby a dispersion containing at least one family of polymer particles of substantially uniform particle size is produced.  The water-soluble emulsifier may be added continuously or incrementally and may be formed in situ. Many suitable comonomers are listed including vinyl and vinylidene halides, vinyl esters, acrylic esters, methacrylic esters and styrene, which may be copolymerized with other halogenated olefins, vinyl esters, acrylic esters, methacrylic esters, maleic esters, fumaric esters, unsaturated acids and the anhydrides, nitriles and amides thereof, olefins and cycloolefins, vinyl aromatic compounds, allyl and isopropenyl esters, and vinyl heterocyclic compounds. The water-insoluble soaps may be lithium and polyvalent metal salts, e.g. beryllium, barium, calcium, magnesium, strontium, cadmium, zinc, tin, lead, titanium and aluminium salts, of saturated, unsaturated and substituted fatty acids, rosin acids and organic sulphates, e.g. barium lauryl sulphate.  The water-soluble emulsifier may be cationic, anionic or non-ionic, e.g. quaternary ammonium salts, alkali metal and amine soaps, alkyl sulphates and hydrocarbon sulphonates, and polyoxyalkylene compounds many suitable examples being listed. Polymerization may be initiated by ultra-violet light, high energy radiation, hydrogen peroxide, persulphates, perphosphates and redox systems.  Examples describe processes using the following materials: (I) vinyl chloride, potassium persulphate, lithium stearate, calcium octanoate, potassium laurate, sodium lauryl sulphate and p-nonylphenol-ethylene oxide condensate; (II and III) vinyl chloride, potassium persulphate, calcium octanoate and potassium laurate; (IV) t.-butyl acrylate, potassium persulphate, calcium palmitate and potassium laurate; (V) vinyl chloride, potassium persulphate, sodium phosphate, lauric acid, calcium hydroxide, sodium laurate and ammonium laurate; (VI) vinyl chloride, hydrogen peroxide, the sodium-iron salt of ethylene diamine tetraacetic acid, sodium phosphate, sodium laurate and ammonium laurate; (VII) vinyl chloride, potassium persulphate, lithium stearate, sodium laurate and the sodium sulphonate of an alkaryl polyether; (VIII) vinyl chloride, potassium persulphate, lithium stearate, octanoic acid, calcium hydroxide and sodium laurate; (IX) vinyl chloride, potassium persulphate, lauric acid, octanoic acid, calcium hydroxide and sodium laurate; (XI) vinyl chloride, potassium persulphate, lithium stearate, calcium octanoate and potassium laurate; (XII) vinyl chloride, potassium persulphate; lithium stearate, calcium octanoate and sodium lauryl sulphate; (XIII) vinyl chloride, potassium persulphate, calcium octanoate and potassium laurate; and (XIV) styrene, potassium persulphate, barium laurate and potassium laurate.