| 摘要 |
To produce a nonwoven, in at least two layers, the two layers are formed separately with different drawn orientation characteristics, to be bonded together at a number of points into a semi-finished product. The semi-finished product is drawn on at least one orientation to give the two layers a different shrinkage potential. To form a multi-layer nonwoven, the different drawn orientation characteristics are achieved by using different fibers in the two layers, or the fibers in one layer have been spun to different parameters from those in the other layer. The fibers in one layer can be drawn to different parameters from the drawing of the second layer. The two layers are bonded together at points in a regular distribution mechanically by an adhesive and/or through a cohesive bonding at the points. The layers are bonded together at a calender. The drawing is on two directions at right angles. One layer has a lower stretch-to-shear value so that, when the layers are drawn, at least some of the fibers shear in one layer while the fibers in the other layer remain undamaged. In a nonwoven structure of three layers, the outer layers have the same drawn orientation characteristics which differ from those at the center layer, so that the inner layer has a higher shrinkage potential than the flanking outer layers. The outer layers have a lower stretch-to-shear value so that, during drawing, some of their fibers shear while the fibers in the center layer are unaffected. The layers with a lower stretch-to-shear value are composed of bicomponent fibers, in a side-by-side array. The nonwoven layers are composed of spun fibers and/or filaments and bicomponent fibers. The semi-finished product is thermally fixed before drawing.
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