Patent GB-1083037-A (GB)
Title: Improvements relating to the production of flexible sheet materials
Inventor: MERRIMAN PETER
IPC: D04H1/498
Filed: 1963-07-31
Abstract: A method of producing flexible sheet material in which the binder is distributed non-uniformly over the thickness of the material comprises preparing a layer of fibrous material, applying to the layer a liquid consisting of a binder and a vaporisable vehicle, and heating one surface of the layer differentially with respect to the other.  The heating step may be followed by a further heating step which serves to evaporate the vehicle and cure the binder.  The fibrous material is preferably confined and compressed during the heating step between metal or other plates or belts, one of which is heated while the other is either left unheated, cooled or heated to a lesser extent.  The fibrous layer preferably consists of fine fibres overlaid on coarser fibres and examples are given in which a layer or layers of fine staple fibres of nylon (which may be crimped) and/or polypropylene staple fibres are overlaid on a layer consisting of crimped continuous nylon monofilaments laid substantially parallel under slight tension and subsequently released.  The layers of fibres may be needled before and after uniting to form the composite fibrous layer.  The binder liquid may comprise a solution, e.g. a solution of a polyurethane rubber or chemicals reacting to form such a rubber in acetone or other organic solvent, or a dispersion, e.g. a rubber latex or aqueous emulsion of a solution of an elastomer in an organic solvent.  A supplementary binder, e.g. a compounded rubber latex, may be applied before or after the non-uniform distribution of binder has been achieved.  The material is particularly serviceable as a substitute for leather.ALSO:A method of producing flexible sheet material in which the binder is distributed non-uniformly over the thickness of the material comprises preparing a layer of fibrous material, applying to the layer a liquid consisting of a binder and a vaporizable vehicle, and heating one surface of the layer differentially with respect to the other.  The heating step may be followed by a further heating step which serves to evaporate the vehicle and cure the binder.  The fibrous material is preferably confined and compressed during the heating step between metal or other plates or belts, one of which is heated while the other is either left unheated, cooled or heated to a lesser extent.  The fibrous layer preferably consists of fine fibres overlaid on coarser fibres and examples are given in which a layer or layers of fine staple fibres of nylon (which may be crimped) and/or polypropylene staple fibres are overlaid on a layer consisting of crimped continuous nylon monofilaments laid substantially parallel under slight tension and subsequently released.  The layers of fibres may be needled before and after uniting to form the composite fibrous layer.  The binder liquid may comprise a solution, e.g. a solution of a polyurethane rubber or chemicals reacting to form such a rubber in acetone or other organic solvent, or a dispersion, e.g. a rubber latex or aqueous emulsion of a solution of an elastomer in an organic solvent.  A supplementary binder, e.g. a compounded rubber latex, may be applied before or after the non-uniform distribution of binder has been achieved and surface finishing coatings, e.g. of a polyurethane lacquer, may also be applied.  The material is particularly serviceable as a substitute for leather.