Patent GB-992636-A (GB)
Title: Polymer dispersions
IPC: C08F2/08
Filed: 1962-02-12
Abstract: Polymer dispersions are made by polymerizing an addition polymerizable monomer charge in a substantially anhydrous liquid hydrocarbon medium in which the resulting polymer is insoluble, the polymerization being carried out in the presence of a hydrophobic polymeric dispersing agent which has in its molecule two distinct polymeric components, one of which has a preferential affinity for the liquid hydrocarbon medium and the other has a preferential affinity for the addition polymer, and adding to the hydrocarbon medium before, during or after polymerization at least one C1-C5 halogenated hydrocarbon containing at least one fluorine atom and 0-3 chlorine atoms, preferably one which is sufficiently volatile to act as a propellant in making an aerosol spray-pack from the polymer dispersions.  Preferred halogenated hydrocarbons are dichlorohexafluoropropane, dichlorotetrafluoroethane, perfluoropentane, dichloro-octafluorobutane, trichlorofluoromethane, dichlorodifluoromethane and monochloropentafluoroethane.  The polymeric dispersing agents are generally made by in situ grafting of the dispersion-forming monomers on to a preformed polymer which is soluble in the hydrocarbon polymerization medium, and which may be preactivated by treatment with an organic peroxide.  Preferred preformed polymers are crepe rubber, a vinyl toluene-butadiene copolymer, a styrene-butadiene copolymer, an isobutylene-isoprene copolymer, cyclized rubber and a vinylpyrrolidone-butyl acrylate-lauryl methacrylate-stearyl methacrylate copolymer. Additional methods of preparing the polymer dispersions are described in Specifications 934,038 and 992,635.  The examples describe the preparation of dispersions from monomer charges consisting of:  (1) methyl methacrylate, ethyl acrylate and maleic anhydride, (3) acrylonitrile, butyl acrylate and maleic anhydride, (4) acrylonitrile and butyl or 2-ethylhexyl acrylate, (5) vinyl acetate, (6) methyl acrylate, (7) methyl methacrylate, (8) methyl methacrylate and ethyl acrylate, and (9) ethyl methacrylate and methacrylic acid.  The resulting dispersions are used for coating various substrates. Specification 893,429 also is referred to.ALSO:Aerosol spray compositions comprise dispersions of addition polymers in liquid hydrocarbons stabilized by graft copolymer dispersing agents, and fluorinated hydrocarbons as propellants. Propellants specified are trichlorofluoromethane and dichlorodifluoromethane. Addition polymers specified are polyvinyl acetate and copolymers of acrylic esters and other acrylic derivatives.  Specifications 893,429 and 992,635 also are referred to.ALSO:Surfaces of metal, glass and leather are coated by applying thereto by casting or spraying polymer dispersions consisting of particles of an addition polymer suspended in a mixture of a liquid hydrocarbon and a halohydrocarbon which contains up to 5 carbon atoms, at least one fluorine atom and 0-3 chlorine atoms, the dispersions being stabilized by a dispersing agent formed by grafting monomer on to a preformed polymer dissolved in the dispersing medium (see Division C3).  When the halohydrocarbon is sufficiently volatile, the polymer dispersion may be applied to the substrate from an aerosol spray pack.  The examples describe coating: (1) metal and glass plates with a dispersion of a methyl methacrylate/ethyl acrylate/maleic anhydride copolymer in mineral spirits and dichlorohexafluoropropane, (2) as in (1), but using dichlorotetrafluoroethane as the halohydrocarbon, (3) metal plates with a dispersion of an acrylonitrile/butyl acrylate/maleic anhydride copolymer in octane and perfluoropentane, (7) metal plates with a dispersion of polymethyl methacrylate in octane and dichlorodifluoromethane, (8) leather with a dispersion of a methyl methacrylate/ethyl acrylate copolymer in toluene and trichlorofluoromethane, and (10) bare and phosphated steel panels with a dispersion of a methyl methacrylate/ethyl acrylate copolymer in mineral spirits and trichlorofluoromethane and/or dichlorodifluoromethane.  Specifications 893,429 and 992,635 also are referred to.ALSO:In an example (9) cellulose yarns are warp sized by passing them through a dispersion in toluene and monochloropentafluoroethane of an ethyl acrylate/methyl methacrylate copolymer stabilized by a graft copolymer of a butadiene-styrene rubber.  Specifications 893,429 and 992,635 also are referred to.