| 摘要 |
785,058. Impregnated stiffening materials. CELASTIC CORPORATION. March 25, 1955 [July 22, 1954], No. 8872/55. Class 140. [Also in Group VII] Sheet material capable of being stiffened is made by impregnating a fibrous sheet material with (a) an aqueous vinyl resin latex containing an anionic surface-active wetting agent; and (b) an aqueous solution of a polyvalent metal salt, separately but in either order, and drying the impregnated sheet material. Stiffening is effected by the action of a solvent for the resin. When the metal salt solution is applied first, the impregnated sheet may be wholly or partly dried before treatment with the resin latex. When the latex is applied first, it may be used in a partly coagulated state brought about by the addition of enough coagulant salt to give it a creamy consistency, the fibrous material treated with this creamed latex being stripped to remove excess, impregnated with a dilute coagulant solution, and dried. The resin contained in the latex may be polystyrene, polymethyl styrene, polyvinyl or vinylidene halides, polyacrylonitrile, polyacrylates or polyalkylacrylates. A plasticizer may be added, e.g. an organic ester, or a copolymer of styrene and butadiene in latex form. Fillers such as bentonite clay or infusorial earth, and thickeners such as methyl cellulose or carboxymethyl cellulose may also be added. The anionic surface-active agent may be an alkali metal organic sulphate, sulphonate, phosphate or phosphonate, or an ammonium soap. The polyvalent metal salt may be a chloride, nitrate, sulphate or acetate of aluminium, magnesium, calcium, strontium, iron, cobalt, tin, copper, chromium or cadmium, or one of the alums. The fibrous sheet may be cotton flannel, felt, paper or a matted fibrous sheet. The material may be used to produce a box toe or counter in a shoe, a laminate with other materials, artificial limbs or shaped moulds, to repair gutters, fenders and motor car bodies, or to cover decks and hulls of small boats. Specification 766,866 is referred to. |
