Patent GB-961043-A (GB)
Title: Aqueous dispersion polymer compositions
IPC: C08F36/20
Filed: 1961-04-05
Abstract: Aqueous dispersions of polymers comprise a continuous aqueous phase having dispersed therein a chain-extended polymer of one or more monovinylidene unsaturated monomers and a small proportion of a divinylidene monomer, the composition being free of microgel and being capable of forming a continuous film when applied to a surface. The dispersions are made by copolymerizing in aqueous emulsion one or more monovinylidene monomers in the presence of an amount of a monomer containing two vinylidene groups insufficient to cause formation of a microgel.  Monovinylidene monomers specified are C1-C18 alkyl acrylates and methacrylates, aralkyl acrylates and methacrylates, vinyl acetate, propionate, laurate, stearate and benzoate, acrylamide and methacrylamide, acrylonitrile, methacrylonitrile, styrene, alpha-methyl styrene, vinyl toluene, vinyl xylene, vinyl chloride, vinyl flouride, acrylic methacrylic, ethacrylic, phenylacrylic, chloroacrylic, crotonic, itaconic, vinylacetic, fumaric and maleic acids and salts thereof, and monoalkyl fumarates and maleates and salts thereof.  Preferably a mixture of monomers is used in which one monomer yields a soft polymer and the other a hard polymer. Di-vinylidene monomers specified are alkylene bis-acrylamides and bis-methacrylamides, di-acrylates and dimethacrylates of dihydric alcohols, vinyl methacrylate, allyl acrylate and methacrylate, divinyl and diallyl phthalates and adipates, divinyl benzene and toluene, divinyl glycol diacetate, and the acrylic and methacrylic esters of allylcarbinol. Polymerization may be initiated by means of organic peroxides, hydro-peroxides and peresters, hydrogen peroxide, inorganic per-salts, azo compounds, redox catalysts made from peroxidic compounds and salts of sulphurous acids which may be activated by ferrous ions, and sodium azide-ceric ammonium sulphate, titanium trichloride-acetone oxime, titanium chloride-hydroxylamine, divalent vanadium-hydroxylamine hydrochloride, and copper sulphate-benzendiazophenyl sulphone combinations.  The polymerization medium may contain a dispersant, e.g. a long chain sulphate or sulphonate, or a water-soluble adduct of ethylene oxide.  The process is preferably carried out by charging a proportion of the monomers initially, and adding the remainder of the monomers and an aqueous dispersant solution as the reaction proceeds.  The examples describe the copolymerization of: (1) butyl acrylate, acrylonitrile, methacrylic acid and methylene-bis-acrylamide (1.7 X 10-2% mol.) in an aqueous medium containing sodium lauryl sulphate and an ammonium persulphate-sodium metabisulphite catalyst, and the resulting copolymer dispersion is neutralized with ammonia; (3) butyl acrylate, acrylonitrile, methacrylic acid and ethylene diacrylate (1 X 10-3% mol.) in an aqueous medium containing sodium lauryl sulphate and an ammonium persulphate-sodium metabisulphite-ferrous ammonium sulphate catalyst, with neutralization of the resulting dispersion with ammonia; and (4) ethyl acrylate, styrene, methacrylic acid and ethylene diacrylate (1 X 10-2 % mol.) containing benzoyl peroxide catalyst, followed by a second stage in which monomer sodium lauryl sulphate ammonium persulphate-sodium metabisulphite and water are added to the reaction mixture with neutralization of the resulting dispersion with ammonia.  Example (2) describes a copolymerization similar to that of (1), followed by the addition of phenol-formaldehyde resin to the neutralized dispersion to produce a coating composition.  Specifications 761,928 and 832,111 are referred to.ALSO:Surfaces are coated with aqueous dispersions of one or more monovinylidene monomers and a small proportion of a divinylidene monomer, the dispersions being free of microgel and capable of forming continuous films when applied to surfaces.  The examples describe: (1) and (2) applying to glass fabric aqueous dispersions of copolymers of butyl acrylate, acrylonitrile, methacrylic acid and methylene bis-acrylamide, which may also contain a small quantity of phenol-formaldehyde resin; and (4) the use of an aqueous dispersion of a copolymer of ethyl acrylate, styrene, methacrylic acid and ethylene diacrylate as a primer for use under baking type appliance finishes and under acrylic resin automotive finishes.  The polymers modified with phenol-aldehyde resins may also be used for enamelling copper wire.  Specifications 761,928 and 832,111 are referred to.