GB1128642A - Process for the production of silicone emulsions - Google Patents

Abstract

1,128,642. Silicone emulsions. FARBENFABRIKEN BAYER A.G. 27 May, 1966 [28 May, 1965], No. 23809/66. Heading C3T. Aqueous silicone emulsions free of emulsifiers are made by reacting (a) polysiloxanes of the formula R n SiCO 4-n/2, wherein n has a value of from 1 to 3, at least 2 of the R radicals are carbofunctional radicals each carrying at least 1 reactive H atom, the remaining R radicals being hydrocarbon radicals with or without inert substituents, with (b) an organic diisocyanate, and with (c) a silicon-free compound carrying at least 1 H atom reactive with -NCO groups or at least 1-NCO group and at least 1 salt type group or group capable of salt formation and, if desired, with (d) a silicon-free chain extender of M.W. not more than 300 carrying reactive H atoms, and where compounds carrying groups capable of salt formation are used, the reaction product is subsequently converted at least partly into salt form, at least the reaction with components (c) and/or (d) either taking place in an organic solvent to which water is added when the reaction is complete and the organic solvent is removed, or in water, or in a watercontaining organic solvent which may be partially removed. The siloxane carbofunctional radicals are organic radicals containing hydroxy, mercapto, carboxy or amino groups. Among the numerous examples of (c) are mercapto-, hydroxy- and amino-carboxylic and -sulphonic acids and addition products thereof, organophosphorus compounds, and compounds carrying groups which can be neutralized, quarternized or ternized with acids, e.g. mono-, di- and tri-hydric alcohols and mono-, di- and triamines. Usually the siloxane (a) is reacted with the diisocyanate (b) to form a pre-polymer which is then reacted with compd. (c) and, if desired with (d), in the presence or absence of organic solvents and water. Several other methods are described. The modified siloxanes are converted into emulsions by spraying the dissolved or liquid solvent-free reaction product into water or by using ultrasonic means. Polyfunctional cross-linking agents, many examples of which are given, may be added with the water added to prepare the emulsion. Emulsifiers may be added, if desired. The emulsions may be blended with dispersions of P.V.C., polyethylene, polystyrene, polybutadiene or polyurethanes. Fillers, plasticizers, pigments, silica sols, Al, clay and asbestos dispersions, may also be added. The products are isolated simply by removing the solvents. Alternatively, by adding electrolytes thereto coagulates are obtained which, after removal of solvent, yield oils, fats, paraffin- or wax-like plastic compositions, pastes, brittle and hard or soft and elastic adhesive films and foils, and pulverizable, crystalline, thermoplastic products. In a typical Example (1) a hydroxymethyl terminated dimethylpolysiloxane was reacted with 1,6-hexanediisocyanate and the product was dissolved in acetone and added to an acetone solution of bis-(aminopropyl)- methylamine; dimethylsulphate was then added, followed by water, and finally the acetone was distilled off leaving a stable emulsion. Uses.-For coating, impregnating and hydrophobing textiles, leather, paper, glass, wood, laminates and foam plastics; for anti-static and crease-proof finishing; as binders for fleeces, cork powder, sawdust, glass fibres, asbestos and paper-like materials; as adhesives, adhesion promotors, laminating agents, and plasticizers; as auxiliaries in textile printing and finishing; as additives for polymer dispersions; as sizing agents and leather-treating agents; as sealants, lubricants, dispersants, emulsifiers, wetting agents and antifoam-agents; as stabilizers for polyurethane foams; as cosmetic skin protectives; as polishing agents, mould release agents and hydraulic liquids; as cleaning agents for various surfaces; as levelling agents for paints and varnishes; as tarnish-proof coatings on panes of glass; as corrosion inhibitors; and for making polyurethanes or other polymers opaque.