Method for Producing an Elastic Web Material

A method for continuous production of a flexible, air-permeable web material with two outer material layers, at least one of which is made from a textile material, between which layers a prestressed, elastic intermediate layer is inserted, where the web material is shortened through the release of tension in the intermediate layer, and can again be extended elastically through exertion of tensile stress, where initially, the front end of the first outer layer of the textile material is applied onto the end section of a longitudinally extended rod-like or pipe-like mould core, and simultaneously with the initiation of a feed motion on the mould core, it is folded around the mould core in a tubular closed form, and then during the feed motion on the mould core, a pressure-sensitive adhesive is applied on the free top surface of the first outer layer;

• where upon the tubular first layer, in the course of the further feed motion on the mould core, is guided through a feed mechanism for a group of elastic threads or strands under selectable elastic prestressing, where the elastic threads or strands are guided in the feed mechanism on a ring-shaped support surrounding the longitudinally extended mould core in individual guides arranged offset from each other in the circumferential direction, and applied onto the first outer layer, and are bound with it by the pressure-sensitive adhesive, where the ring-shaped support of the individual guides during the feed motion of the tubular first layer on the mould core is driven rotationally about the longitudinal axis of the mould core, so that the threads or strands are applied on the tubular first layer, because of the overlaid feed motion of the first layer and the rotation of the supports running obliquely and oriented essentially parallel to each other and surrounding the tubular first layer in each case, in the form of a tubular reinforcement, and then the second material layer is applied onto the first tubular material layer, overlaid with the applied groups of elastic threads or strands, and during the further feed motion is folded tubularly around the mould core, and is bonded through adhesion to the first material layer and the applied elastic threads or strands, whereupon the so created tube-like web material is sliced open in the longitudinal direction and unfolded into an essentially plane-surface web material, characterised in that
• through a further feed mechanism, downstream in the feed direction, driven in the opposite direction of rotation, in each case a further group of elastic threads or strands oriented essentially parallel to each other, running diagonally in the opposite direction to the first group, are applied to the applied group of elastic threads or strands onto the tubular layer and adhesively bonded with it, and
• that the elastic threads or strands of both groups during the application onto and the adhesive bonding are bound with the tubular web material, where said threads or strands are lengthened, in contrast to their unstressed state, through a prestressing corresponding to the desired elastic elongation of the finished web material.