FIBER FLEECE CONTAINING A POLYMERIC REINFORCING MATERIAL

1362806 Non-woven fabrics KALLE AG 28 Oct 1971 [30 Oct 1970 (2)] 50201/71 Heading D1R The fibres of a needled non-woven fabric are coated with a wash-proof synthetic material and the coated fibres are in turn surrounded by an organic elastic polymeric matrix, there being no adhesion between the matrix and the synthetic material. The matrix comprises 10-80% by weight of the product, which has a density of 0.1 to 0.28 gn/cm3, a tensile strength of at least 0.01 kg/mm2, a tear propagation resistance of at least 7 kg/mm and a tensile stress of not more than 0.03 kg/mm2 at 10% elongation. The fibres, are staple length polyethylene terephthalate, polyamide, polypropylene polyacrylonitrile or mixtures thereof, which fibres shrink longitudinally on heating, optionally mixed with up to 50% of wool, hair, cotton, hemp, jute sisal or flax fibres, are in the form of a matted needled fleece. The synthetic coating material comprises 2 to 20% by weight of the product, and may be an ethylene urea, a fatty amine, paraffin wax, etherified fat modified synthetic resin, cross-linkable or non cross-linkable polymeric siloxane compounds such as dimethylpolysiloxane and hydrogen-methylpolysiloxane, or crosslinkable polymers having perfluorated aliphatic side chains of preferably 6 to 14 carbon atoms, or a melamine/formaldehyde or urea formaldehyde precondensate. The coating may be applied by immersing the fleece in an aqueous solution or dispersion and then heating to remove the liquid and fix the coating upon the fibres. Alternatively the coating may be applied in a halogenated hydrocarbon solution together with a phenol which swells the fibres. The fleece is then washed with solvent to remove the phenol and heated. The matrix is then applied either as an aqueous dispersion which is then coagulated to 38-45‹C or in a water-miscible non fibre swelling organic solvent, coagulation then being accomplished by addition of water. Heating at 100-180‹C drys the product and deswells the fibres if they have been swollen by a phenol. The matrix may be natural or synthetic rubber, polyacrylate, butadiene-acrylonitrile-methacrylic acid copolymer or polyurethane.