Improvements in non-woven fabrics comprising bonded fibres

摘要

880,702. Agglutinated fibrous fabrics. LIPACO S.A. July 2, 1958 [July 3, 1957 ; Oct. 17, 1957], No. 21161/58. Class 140. Non-woven textile fabric comprises regenerated cellulose fibres cross-linked to bring their water-imbibition to between 35 and 90%, a substantial portion of the fibres being bonded to one another by coalescence over short lengths of the fibres. Coalescence is effected by treatment with aqueous caustic soda solution. Fibres made by the viscose or cuprammonium processes may be used. Suitable reagents for effecting cross-linking are formaldehyde, glutaraldehyde, glyoxal, urea-formaldehyde, dicyandiamide-formaldehyde, melamine-formaldehyde, guanidine-formaldehyde and methylol-amino-epihalohydrin compounds; also resins formed by reaction of formaldehyde and acrolein or acetone and formaldehyde; polyepoxy resins such as condensation products of epichlorohydrin with ethylene glycols. The fibres may be treated with the cross-linking reagent while in the gel state following their production the cross-linking reagent may be applied in substantially precondensed monomeric or low polymer state, as an aqueous solution or dispersion and may contain a catalyst and finishing agent. The caustic soda solution may be applied to the cross-linked fibres by spraying the fibres on a porous moving belt, after which the fibres may be compressed between rolls, neutralized, washed and dried. As shown (Fig. 1), a layer of cross-linked regenerated cellulose fibres 1, is laid in porous moving belt 2 and passed between pairs of rollers 3, 31; 4, 41 and 5, 51. Aqueous caustic soda solution is run from tank 6 through pipe 7 and nozzles 8, 9 and 10 on to the layer of fibres. Excess caustic soda solution is collected in basin 11 and returned to tank 6 through pipe 12. The fibrous layer then passes between squeeze rolls 13,131, through bath 14 containing a solution of acetic acid for neutralization, bath 15 containing neutral wash water and drier 16. Fig. 2 shows a cross-section of non-woven fabric according to the invention, wherein the fibres retain their identity and there are areas (as at 17) of coalescence with adjacent fibres. Specifications 796,815 and 872,656 are referred to.