Patent GB-1136806-A (GB)
Title: Producing fibrous sheet products
IPC: D04H1/74
Filed: 1966-05-17
Abstract: 1,136,806. Non-woven fabrics. E. I. DU PONT DE NEMOURS & CO. 17 May, 1966 [17 May, 1965], No. 21744/66. Headings D1N and D1R. [Also in Division B2] A fibrous sheet of synthetic, natural, glass, metal or ceramic fibres or blends thereof having its fibres generally transverse of the plane of the sheet is formed by:- (a) forwarding an elongate sheet of fibres with the fibres generally transverse of the length of the sheet through a compression and slitter roll to cut the sheet into strips, (b) maintaining the strips compressed and while conveying them and turning them through 90‹ about their longitudinal axes, (c) releasing them in side by side position so as to form a batt. The initial sheet of fibres may be formed by cross laying, on a conveyor, a web of fibres from a carding engine (Fig. 1 not shown). The sheet may be cut by revolving cutters engaging grooves in an associated roller or similar cutters on an associated roller or by vertical blades or reciprocating blades. Leaving the cutter rollers (13, 14), Fig. 4 not shown, each strip is held compressed by a pair of belts (20, 21) of polyethylene terephthalic and the belts and strip are rotated through 90‹ and brought into engagement with a drum (27) provided with slots into which the on-edge belts can move leaving the strips in edge to edge relation. The resulting batt is conveyed away by belts (30, 31) which may be run at a slower speed to longitudinally compress the batt. The individual strips may alternatively be removed from between the belts (20, 21) by fixed deflecting member or by endless belts. The resulting batt may be wound up or sliced as shown in Fig. 2. In an alternative arrangement the rotated fibrous strips, are allowed to unite on an horizontal conveyor such as a Fourdrinier wire with upstanding wire projections. Bonding The batt may be bonded at one or more stages in its manufacture. The binder may comprise natural and synthetic rubbers, polyurethanes, polyamides, polyesters, acrylic polymers, copolymers and terpolymers, natural gums and resins, starches, cellulose derivatives such as carboxymethylcellulose. The binder may be a thermosetting composition such as neoprene, phenol-formaldehyde resins, ureaformaldehyde resins, melamineformaldehyde resins. Alternatively the binder may be thermoplastic. The binder may be applied by spraying, dipping, padding or vacuum means. Alternatively a solvent or partial solvent may be incorporated in the fibre mass and then activated to bond the fibres. Binder fibres with a lower melting point or greater solutibility than the structural fibres may be incorporated in the fibrous mass and then activated at a suitable point in the process. Powdered binder may be sifted onto one face of the batt so that after curing, the binder density varies through the sheet. Alternatively where the binder is uniform in the sheet the curing may be non-uniform, e.g. applied to one side to leave a soft surface on the other. The uncured binder may be left in place or removed by a solvent. Adhesive may be applied to a face of the batt or a wafer cut therefrom. The adhesive may be a polyester resin, a polyamide resin, a polyethylene resin, a natural or synthetic rubber composition. The adhesive may be applied by spraying, dipping, doctoring, laminating (i.e. by bringing an adhesive coated backing into contact with the sheet) or by application of a film followed by melting. The density of the fibres through the sheet may be varied by compressing the sheet while the binder therein is being cured and maintaining a temperature gradient across the sheet. The resulting sheet may be sliced. In a further form card webs may be rolled into slivers and laid crossways, two or three deep, to form an elongate batt, slivers of different colour may be used. The batt is 'then reformed as described above. The batt formed above may be used as pile fabric, apparel, industrial textile products, pillows, upholstery, carpets, blankets, apparel interlinings, outer wear, bed spreads, bath robes, insulation. An example is given of the formation of a particular batt.