| 摘要 |
A planar composite sheet material having enhanced mechanical properties as a backing material for a carpet underlay comprises a crepe sheet material and a plain sheet material, preferably crepe paper and plain paper, a surface of the plain sheet material being maintained in contact with the surface of the crepe sheet material by side-by-side rows of stitches formed through both the crepe sheet material and the plain sheet material. The side-by-side rows of stitches are transverse to the crimps in the crepe sheet material and are effective to give dimensional stability to the crepe sheet material. In one embodiment both sheet materials are deformed so that rows of rounded projections, which are raised in both sheet materials, lie between at least some of the side-by-side rows of stitches, both sheet materials being deformed without being punctured. Advantageously there is at least one row of rounded projections raised in both sheet materials between each pair of side-by-side rows of stitches. |
