| 摘要 |
928,893. Fibrous sheets. NORMANLIN, S. a.r.L., R. MOREL, and C. DE JARNY. Oct. 8, 1959 [Oct. 9, 1958; March 17, 1959; July 16, 1959], No. 34199/59. Class 42 (2). A method of making sheets of non-woven organic vegetable or animal fibres, e.g. flax fibres, adapted to be used in forming resin-bonded laminates, or as reinforcement for plaster of Paris or cement building elements comprises forming a layer of unorientated interengaging fibres, so as to leave interstices through which a binder can readily pass, introducing therein a solution of an impregnating and adhesive coagulable organic colloid followed by a coagulant, to form a non-adhesive product inert to synthetic resins or their cross-linking agents, compressing the impregnated sheets by rolling, and drying and finishing them. The treatment of the invention protects the fibres against further impregnation by sealing them prior to their introduction into a compound structure; the . fibres thereby retain their natural properties and are enabled to exert the maximum reinforcing effect upon incorporation in a compound structure. Specified impregnants are solutions of casein (coagulable by formaldehyde), or of gelatine or an alginate (coagulable by aluminium acetate or alum). As shown, organic animal or vegetable fibres in bulk formation, 1, are disintegrated at 2 and dispersed inside a chamber 3 where they are collected by a roller 4 subjected to suction at 5 and formed into a sheet 6 which passes off the roller 4 on to a conveyer belt 7 formed of stainless metal gauze. The fibrous sheet is thereby conveyed into a chamber 8 where it is impregnated with an atomized solution of casein from an atomizer 9. Thence the sheet enters a chamber 10 where an aqueous solution of formaldehyde is projected upon it from an atomizer 11, whereby the adhesive is coagulated, after which the sheet passes between pressure rollers 12, 13 and thence by a conveyer belt 15 through an oven 16 where the sheet is dried and the coagulation completed. Thence the sheet passes through a vat 17 containing material for neutralizing any contained acidic or alkaline material, over driving rollers 19, through a vat 18 containing running water and through an oven 21 for final drying. The finished sheet 22 emerging from the oven is then calendered between heated rollers 23, 24 and is trimmed in width by disc shearers 25. The fibres of the product may be waterproofed by treatment with a diisocyanate, e.g. stilbene diisocyanate, which may react with OH groups in the fibres or with such a diisocyanate together with a polyhydroxy ester. Specification 642,890 is referred to. |
