| 摘要 |
The tensile strength of cellulosic fabrics rendered crease resistant by crosslinking is improved by a process comprising (1) stretching assemblages containing natural cellulosic fibres in a direction substantially parallel to the long axis of the fibres whereby an elongation of the cellulosic material is effected, (2) forming a fabric from the stretched assemblages of fibres and (3) crosslinking the fabric with a cellulose cross-linking agent. The assemblages are yarns or bundles of fibres and include slivers, rovings, threads, yarns and ply-yarns and may comprise cotton or linen alone or in admixture with other fibres. The assemblages may be stretched in one or more stages by up to 8% of their initial length, a stretching of up to 80% of their elongation at break being preferred. Loose assemblages of staple fibres in the form of slivers or rovings may be stretched by application of the stress-producing forces across distances smaller than the staple length but the stress-producing force to assemblages of staple fibres in the form of yarns or ply-yarns may be across distances exceeding the length of the staples. Stretching may be achieved by means of two delivery means operated at slightly different speeds, e.g. two pairs of rollers operated in series in which the second roller pair operates at a higher speed than the first roller pair, by means of two rollers which draw the assemblage past a friction-producing means, by means of two interlocking toothed rollers or one tooth roller pressed against a soft rubber roller or by means of devices in which the assemblages are pressed between two rubber draw tapes. The fibres may be swollen by means of hot or cold water which may contain a wetting agent, amine solutions or steam during stretching and after stretching may be dried, in the case of single yarns or rovings converted into yarns or ply yarns, woven or knitted into fabrics, mercerized, bleached, dyed and/or printed and then treated with the cross-linking agent which may be a resin precondensate of formaldehyde with urea, thiourea, cyclic derivatives of urea in the form of heterocyclic 5-or 6-membered ring compounds, a carbamate, acetylene diurea or melamine, an acetal, an epoxide, a polyepoxide or a halohydrin. The crosslinking agent may be applied to the fabric in the form of an aqueous solution which may also contain zinc chloride or nitrate by dipping, padding or spraying and the fabric then dried and cured.
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