EP-A-0 333 209 makes known binding endless elastomer fibres and wood pulp fibres together hydrodynamically and in so doing strengthening the composite non-woven fabric. With this method of strengthening there is the danger that a large quantity of pulp fibres is washed out of the system, in other words fibres are lost. In addition, it has also been established in practice that the outer layer of such a composite non-woven fabric tends to pellet, as is described in WO 90/04066. For improvement, EP-A-0 540 041 proposes treating the endless fibre non-woven fabric hydrodynamically before the application of the pulp fibres. This is to give the non-woven fabric not only greater strength, but also to improve the absorption power of the pulp fibres and the fluid distribution properties. According to this document, the pulp fibres are then simply applied to the needled non-woven fabric and are then dried with the non-woven fabric for bonding or are pressed mechanically into the non-woven fabric.
It has been possible to establish that none of these types of producing non-woven fabric products fulfils the conditions in practice. More especially, complaints have been made about the composite non-woven fabrics tending to pellet, on the outer side of the endless fibre non-woven fabric.
USPTO Backgrounds
USPTO Backgrounds