Patent GB-501041-A (GB)
Title: Improved manufacture of stiff bandages
IPC: A61L15/07
Filed: 1937-05-18
Abstract: 501,041. Stiffening bandages; coated fabrics; synthetic resin compositions. CHEMISCHE FORSCHUNGS-GES. May 18, 1937, Nos. 13827 and 13828. Convention dates, May 16, 1936 and Aug. 22, 1936. [Class 81 (ii)] [Also in Groups IV and VIII] Bandages, which stiffen after application and are employable in place of plaster-of-Paris bandages, are produced by coating or impregnating fabrics or paper with solutions of waterinsoluble, and only slightly water-swellable polymerized vinyl-alcohol derivatives, or polymerized vinyl derivatives of aromatic hydrocarbons, in admixture with magnesia as filling material, cellulose derivatives such as cellulose acetate or nitrate, polyacrylic acid derivatives, or softening agents, being also added if desired. The magnesia may be supplemented by a porous or superficially-active material, e.g kieselguhr, and medicinal substances may also be incorporated. The filling material may be suspended in the solution of the polyvinyl compound employed or may be applied by drawing the coated or impregnated bandage through the dry filler or through a suspension thereof in an organic liquid. An additional coating of a hydrophile or water-soluble polyvinyl compound may be applied to the bandage for use under tropical conditions. Examples ; (1) a bandage is impregnated with 1600 cc. of a 40 per cent solution of polyvinyl alcohol acetaldehyde acetal in 96 per cent alcohol, the solution containing 150 gms. of magnesia powder ; the dry bandage is softened before use in a solvent such as ether, acetone or methylene chloride, and after application becomes stiff on drying; (2) 100 gms. of magnesia powder are added to 1000 cc. of a 14 per cent solution of polyvinyl alcohol formaldehyde acetal in a mixture of alcohol and dichlorethylene; the paste so formed is spread upon bandage material; (3) 500 gms. of medium viscous polyvinyl acetate are dissolved in 500 gms. of 96 per cent spirit and 150 gms. of magnesia added to form a paste which is applied to one or both sides of a paper or other bandage ; alternatively, a mixture of 2 parts of polyvinyl acetate, in 50 per cent solution in acetone, and 1 part of nitrocellulose in 20 per cent solution in butyl acetate, may replace the polyvinyl acetate solution employed ; an additional coating of polyvinyl acetate or polyvinyl alcohol solution may be applied for protection in the tropics ; the bandage produced may be softened in hot water and stiffens on drying ; (4) a bandage of fabric, wire netting, gauze, paper or any of these in admixture, is drawn through a 20 per cent solution of polyvinyl acetate prepared as in Specification 271,090, [Class 121], and sub. sequently through a suspension containing 50 gms. of magnesia to 125 cc. methanol or methylene chloride, or through dry magnesia ; alternatively, a coating solution comprising a 15 per cent solution of polyvinyl acetate in methanol containing 3 to 5 per cent of kieselguhr, to increase the adhesion of the coating and facilitate drying, may be employed : a protective coating of acetate or polyvinyl alcohol may be applied ; the resulting bandage is softenable before use in cold water. Specifications 344,113, [Group XV], 363,676, 369,944, [both in Group VIII], 372,327, 373,947, and 416,412, [Group V], also are referred to. The Specification as open to inspection under Sect. 91 describes the use of plaster-of-Paris or asbestos as fillers and the preparation of the bandages without fillers. This subject-matter does not appear in the Specification as acceptecl.