Sealing matting interlayer fibre bond strength enhancement - by needle bonding projecting thermoplastic fibres and tufts resin adhered at outer surfaces for swelling clay layer water and/or oil impermeability

摘要

Layers are needle bonded together to extend fibres and fibre tufts from actively needled nonwovens through the other active or passive needled layers. The projecting fibres and fibre tufts are adhesive bonded to the surfaces and/or melted in place if they are of a thermoplastic material. Pref. nonwoven is used for the carrier and covering layers, with the needling to give projecting fibres and/or tufts on both sides, to be adhesive bonded at surface(s). The initial needling is downwards, from above, and upwards needling from below. The material can also be needled at a single station fitted with needles with downwards and upwards barbs, or the needles can carry barbs of both types. The projecting fibres and/or tufts are bonded with an adhesive pref. a reaction resin and esp. polyurethane or epoxy resin system. The polyurethane system gives a foamed layer which, used at a cover layer, is open pored. Where the fibre/tuft bonding is by melting, this is in a semicontinuous process, in steps, through pressure by a hot plate. The melt bonding can also be in a continuous process, using a heated roller, flame application or IR radiation, or by moving close to electric heaters where pref. a thermoplastic film is laminated in place simultaneously. USE/ADVANTAGE - Using powder clay with a particle size where 90% is less than 0.06mm, and 70% is less than 0.002mm.