| 摘要 |
Such a filter mat has a fibre layer (5) composed of unneedled, coarse man-made and/or non-rotting natural fibres or fibre wastes, and this layer (5) is joined on one side of the mat to a filter-active layer (4), preferably comprising a woven fabric, an unneedled spunbonded or unneedled nonwoven, by stitch-bonding (3). The stitch-bonding (3) comprises threads of a heat-shrinkable material, preferably metallic threads or synthetic monofilaments, which form a three-dimensional structure by interlooping through the mat and which form constrictions and depressions when the thread material shrinks, with zigzag-shaped (toothed) constrictions (1) being formed on the upper surface of the mat and straight-line ridges (2) which extend transversely to the longitudinal direction of the mat being formed on the lower surface of the mat. The stitch-bonding (3) produces on the one hand a reliable and permanent join between the two layers (4, 5) and on the other an improved anti-slip effect. <IMAGE>
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