Patent GB-572995-A (GB)
Title: Treatment of paper or textile fabrics
IPC: D06M14/08
Filed: 1943-02-15
Abstract: Paper or textile fabrics are impregnated with resinous polymerization products by applying thereto one or more monomeric readily polymerizable compounds in the form of a solution or aqueous dispersion and then causing the monomeric compound to polymerize thereon, polymerization being effected in the presence of a catalyst and under conditions in which the action of molecular oxygen (e.g. atmospheric oxygen) is diminished or entirely suppressed.  The monomeric compound may be a vinyl or vinylidene compound, e.g. acrylic acid, methacrylic acid, or an ester thereof, or acrylonitrile, methacrylamide, styrene, or a vinyl ester or ether. The textile fabrics may be woven or knitted and may comprise fibres of wool, cotton, jute, regenerated cellulose, cellulose acetate, or synthetic linear polyamide. Methyl, ethyl, 2-ethyl hexyl, octadecyl, b -ethoxyethyl methacrylate, and n-butyl methacrylates or acrylates may be used. The emulsions or solutions may contain plasticizers, thickeners, dispersing, or emulsifying agents.  Persulphuric acid or water-soluble persulphates may be used as polymerization catalysts. They may be applied to the paper or fabrics in the form of dilute aqueous solutions.  The polymerization may be carried out in the absence of air or oxygen or in the presence of oxygen-acceptors such as sulphurous acid, hydrosulphites, or pyrosulphites.  The polymerization may be carried out at temperatures as low as 30 DEG C.  When solutions of the polymerizable compound are used, all or part of the solvent should be water or another ionising liquid, e.g. dimethylformamide, or aqueous ethyl alcohol.  Deposition of small amounts of polymers on the paper or fabrics causes small changes in handle, whilst deposition of larger amounts gives fabrics resembling oiled-silk, or fabrics which may be used as interlayers in the fabrication of laminated structures.  In an example, an emulsion of b -ethoxyethyl methacrylate is made by stirring the monomer into an aqueous solution containing wheat starch and oleyl sodium sulphate. A cotton fabric is impregnated with the emulsion and then squeezed. It is then immersed in a warm aqueous solution of ammonium persulphate, sodium hydrosulphite and common salt.  A stiff finish is obtained.  The treatment may be repeated to increase the amount of polymer deposited.  In another example, woollen cloth is immersed in a solution of methyl methacrylate in aqueous ethyl alcohol.  To the solution there is added a mixture of ammonium persulphate and sodium hydrosulphite, and the solution is then heated.  In another example, woollen cloth is soaked in a solution of methacrylamide and ammonium persulphate.  It is squeezed and then exposed to a current of sulphur dioxide or carbon dioxide.  Absorbent paper is immersed in an aqueous emulsion of styrene containing sodium oleyl sulphate.  The paper is transferred to an aqueous solution containing a persulphate, hydrosulphite and common salt.  It is removed, washed and dried. The paper is weighted by deposition of the polymer.  A mixture of methyl methacrylate and dibutyl phthalate may be used instead of styrene. In another example, calcium sulphite is deposited in a cotton fabric by successive treatment with calcium acetate and sodium sulphite.  It is then treated with a warm solution of methyl acrylate and ammonium persulphate.