| 摘要 |
A nonwoven fabric is made by segmentally bonding a fibrous web containing at least five per cent. of individually retractable or elongatable fibres and subjected to a treatment to effect such retraction or elongation to impart bulk to the unbonded areas. The fibrous web may be formed by carding, garnetting, air-laying and paper-making techniques for staple fibres whereas continuous filaments may be deposited with the aid of high-velocity turbulent fluid jets in random loopy manner on a suitable receiving surface. The segmental bonding may be achieved by dielectric welding as in Specification 1,092,373, or by applying a natural or synthetic resin from an engraved printing roll, or if the web contains thermoplastic fibres, bonding by applying heat and pressure using a heated embossed roller. Retraction of the fibres may be effected by heating, e.g. by the application to the web of hot water, steam, air or other fluid at a temperature below the fusion temperature of the fibres, or by chemical action, e.g. of a mild acid or alkali, and may be accompanied by crimping of the fibres. Fibres or filaments having two fibre-forming components, of which one has a higher shrinkage than the other; are particularly suitable and may be formed from polyamides, polyesters, polyesteramides, polysulphonamides, polyolefines, polyurethanes or combinations thereof. The two components may lie side by side or in a sheath-and-core relationship in the filament. Other fibres which may be used include polyethylene terephthalate, which is retractable with accompanying crimping, various copolyamides, which shrink but do not crimp, and certain polyesters, polyurethanes and polyamides, which are elongatable. The web may also contain fibres whose length is not affected by the shrinking or elongating treatment. |
