Patent ES-296121-A1 (ES)
Title: Bonded non-woven fibrous materials
IPC: B05B15/68
Filed: 1964-02-05
Abstract: Non-woven fibrous hat bodies comprising at least 5% of composite fibres capable of being crimped and of adhering to adjacent fibres are subjected to at least one treatment to develop the crimp and activate the potentially adhesive characteristic. The body may be formed by winding a strip of such fibrous material around a rotatable hat former in overlapping relation, Fig. 4 not shown, and heating the assembly to cause the layers to shrink by crimping and to adhere to each other. The lines defining the overlapping areas may substantially disappear during heating otherwise surface finishing of the hat body is necessary. Alternatively the body is formed by depositing fibres on a former, optionally with the application of suction, and then heating them.ALSO:A porous non-woven fibrous assembly comprises at least 5% of crimped composite fibres. (The term "fibres" includes filaments.) These fibres comprise at least two fibre-forming synthetic polymeric components arranged in distinct zones across the cross-section of each fibre, each component is continuous along the length of each fibre, and at least one, but not all, of the components is potentially adhesive and is located so as to form at least a portion of the peripheral surface of each fibre. By "potentially adhesive" is meant capable of being rendered adhesive without affecting any other component. The crimp is derived from different physical properties of the components. The assembly is strengthened and stabilised by entanglement of the fibres due to crimp, and by bonding between the potentially adhesive component and contiguous fibres. This product may be made by forming a fibrous assembly containing at least 5% of the composite fibres, and subjecting it to at least one treatment to develop the latent crimp of the fibres and to activate the potentially adhesive component. The components may lie side by side or the potentially adhesive component may eccentrically enclose the other. The potential crimp of the filaments may be due to an asymmetry of physical properties over the cross section of an artificial fibre forming one component of the filament or to a difference in the physical properties, e.g. different residual shrinkages of the two components. The fibre-forming polymers may be polyamides, polyesters, polyesteramides, polyureas, polyurethanes, proteinaceous polymers, cellulosics, acrylonitrile polymers, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polymers of methyl or ethyl acrylates, methacrylates, polystyrene, polysulphonamides, polyolefines, or combinations of these polymers. Preferably both components are chemically similar. Plasticisers, pigments, dyes, moth-or fire-proofing agents, fillers, abrasives, and/or light stabilisers may be included in the filament composition and plasticisers or soft resins may be included to lower the softening point of the adhesive component. The web may be formed by carding, or garnetting and/or cross lapping, by air-laying, by direct deposition of the filaments on stationary or moving surfaces or by wet-laying methods, as e.g. by the use of a Fourdrinier or other paper-making machine. A light woven scrim may be incorporated between two webs and the fibres needled thereto to provide a finished article of greater strength. The webs may also contain non-activatable fibres such as cotton, silk, wool, flax, casein, kapok, asbestos, rock wool, glass fibres, regenerated cellulose and synthetic polymeric fibres, such as polyamides and polyethylene terephthalate. Crimping may be effected by application of heat or suitable chemical treatment, e.g. by treatment with dilute acids or alkalis or swelling agents. The activation of the potentially adhesive component may be effected in the same or in a subsequent treatment. Chemical treatments given as examples include immersion of the web in nitric acid or in a formaldehyde/glycerol solution or treatment with anhydrous liquid ammonia. The porous fabric produced may be embossed, napped, sheared or moulded to provide shaped articles, e.g. thermal insulation for pipes, or items of wearing apparel. Alternatively the fibres may be laid on a suitably shaped form or mould and crimped and activated to provide shaped articles e.g. hat bodies.ALSO:A porous non-woven fibrous assembly comprises at least 5% of crimped composite fibres. (The term "fibres" includes filaments.) These fibres comprise at least two fibre-forming synthetic polymeric components arranged in distinct zones across the cross-section of each fibre, each component is continuous along the length of each fibre, and at least one, but not all, of the components is potentially adhesive and is located so as to form at least a portion of the peripheral surface of each fibre. By "potentially adhesive" is meant capable of being rendered adhesive without affecting any other component. The crimp is derived from different physical properties of the components. The assembly is strengthened and stabilised by entanglement of the fibres due to crimp, and by bonding between the potentially adhesive component and contiguous fibres. This product may be made by forming a fibrous assembly containing at least 5% of the composite fibres, and subjecting it to at least one treatment to develop the latent crimp of the fibres and to activate the potentially adhesive component. The components may lie side by side or the potentially adhesive component may eccentrically enclose the other. The potential crimp of the filaments may be due to an asymmetry of physical properties over the cross section of an artificial fibre forming one component of the filament or to a difference in the physical properties, e.g. different residual shrinkages of the two components. The fibre-forming polymers may be polyamides, polyesters, polyesteramides, polyureas, polyurethanes, proteinaceous polymers, cellulosics, acrylonitrile polymers, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polymers of methyl or ethyl acrylates, methacrylates, polystyrene, polysulphonamides, polyolefines, or combinations of these polymers. Preferably both components are chemically similar. Plasticisers, pigments, dyes, moth-or fire-proofing agents, fillers, abrasives, and/or light stabilisers may be included in the filament composition and plasticisers or soft resins may be included to lower the softening point of the adhesive component. The web may be formed by carding, or garnetting and/or cross lapping, by air-laying, by direct deposition of the filaments on stationary or moving surfaces or by wet-laying methods, as e.g. by the use of a Fourdrinier or other paper-making machine. A light woven scrim may be incorporated between two webs and the fibres needled thereto to provide a finished article of greater strength. The webs may also contain non-activatable fibres such as cotton, silk, wool, flax, casein, kapok, asbestos, rock wool, glass fibres, regenerated cellulose and synthetic polymeric fibres, such as polyamides and polyethylene terephthalate. Crimping may be effected by application of heat or suitable chemical treatment, e.g. by treatment with dilute acids or alkalis or swelling agents. The activation of the potentially adhesive component may be effected in the same or in a subsequent treatment. Chemical treatments given as examples include immersion of the web in nitric acid or in a formaldehyde/glycerol solution or treatment with anhydrous liquid ammonia. A coating of plasticized polyvinyl chloride or of polyurethane may be applied to the web.