process for the manufacture of textile flächengebilden with high air and water vapor permeability and large moisture holding capacity

摘要

1365734 Foam coated permeable sheets FELDMUHLE ANLAGEN-UND PRODUKTIONSGESELLSCHAFT mbH 8 Sept 1971 [8 Sept 1970 24 Aug 1971] 41919/71 Heading B2E [Also in Division B5] A process for making a sheet material having a high permeability to water vapour and air and a high water absorbance comprising a pair of non-woven fibrous sheets 21 and 22 joined by a foamed plastics layer 23 is characterised in that a coagulating agent for the foamed plastics is applied in a discontinuous form to the inward facing surface of each sheet and that the foamed plastics is subsequently applied between the fibrous sheets in a form in which it is capable of penetrating the fibrous sheet material, and that the resultant product is coated on each surface, firstly with a foamed synthetic plastics dispersion and secondly with a coagulating agent which is preferably applied discontinuously and the coatings dried. The fibrous sheets may be formed from natural cellulosic fibres, cellulose ester or cellulose ether fibres, polyamide fibres or polyester fibres and preferably contain binding fibres e.g. cellulose coated plastics fibres. The foam of the substrate product may be an acrylic resin, a polyurethane or a natural or synthetic rubber e.g. a butadiene-styrene copolymer or a butadiene-acrylonitrile copolymer. The coagulating agent which may comprise alum or sodium sulphate may be applied by dusting or as liquid spots. In one embodiment, the coagulating agent is a material e.g. ammonium carbonate which also functions as a foaming agent. In another embodiment, the coagulating agent is used together with a foaming agent. When a liquid coagulating agent is used, it may be dried prior to application of the foam. The products of the invention which may be slit through the foam layer, may be roughened and may be used as substitutes for leather. The outer coating may be applied by doctor blade as a dispersion of a composition based on acrylic resin with foam binding agents and thickening agents, and then pulverent Na 2 SO 4 may be applied as coagulent with subsequent drying.