GB824399A - Method and apparatus for crimping fibres - Google Patents

Abstract

In a process for permanently crimping cellulosic fibres, e.g of regenerated cellulose, cotton, linen, hemp, ramie or jute, in the form of a rape or sliver of carded fibres or a tow or bundle of continuous filaments which may have been twisted into yarn, the fibres are fed continuously into a closed crimping zone against a mass of crimped fibres, advanced along the zone to a discharge point at a point in advance of which the fibres are impregnated with material having groups which react with cellulose under heat to fix the crimp in the fibres, and are then heated to produce such reaction. The crimped fibres may be advanced to the discharge point at a predetermined rate dependent upon the dwell of fibres in the zone during which the impregnant is, at least partially, cured. The impregnant may be (aqueous solutions of) urea formaldehyde precondensates such as sesquimethylol urea, formaldehyde precondensates of modified ureas such as dimethylol ethylene, propylene or butylene ureas, methylol melamines such as mixtures of dimethylol and trimethylol melamines or tetramethylol and pentamethylol melamines, methylated - methylol melamines such as dimethyl trimethylol melamines. Examples of added catalysts include solutions of <PICT:0824399/IV(c)/1> magnesium chloride hexahydrate or 2-methyl-2 - aminopropanol - 1 - hydrochloride, hydrogen chloride, which may be in gaseous state. Examples of added cationic softeners include stearamidoethyl urea monoacetate and dimethyl ammonium methyl sulphate of monostearyl-metaphenylene diamine. Polyvinyl alcohol may also be added to the impregnating liquid. As shown, filament tow or yarn is passed through feed rollers 11 into an impregnating solution 12 in a tank 13, removed through squeeze rolls 14, fed through a drier 15 and around guide rolls 16 to a guide 17 and is fed by adjustably spring-loaded driven rollers 29, 30 into a crimping chamber formed by sleeves 25, 26, 27, which may be heated by controlled electrical units 45, 46, 47, within blocks 20, 21, 22. The sleeves are joined by collars 50, 51 which have ports 52, 53, communicating with pipes 54, 55, through which fluid, regulated by valves 56, 57, may be fed to the chamber: fluid, regualted by valve 65, may be introduced to sleeve 25 through ports 60. Steam and vapour escape through ports 76, 77, 78 and passages 79, 80, 81. Crimped filaments &c. 69 are withdrawn through a hollow loading plug 68 by rollers 71, operated at a predetermined and adjustable speed relative to the filaments feed rate, and may be passed through an oven 73 for final curing of the impregnant before winding. Catalyst(s) may be introduced through pipe 64 or 54 and/or impregnant introduced through pipe(s) 64, 54 and/or 55, and the curing may be effected in or divided between sleeve 27 and oven 73; softening agent or lubricant may be introduced through pipe 54 or 55 or into the top of sleeve 27.