Patent GB-1105483-A (GB)
Title: Improvements relating to flexible sheet material
Inventor: HIGGS MAURICE WILLIAM
IPC: D04H3/009
Filed: 1964-03-12
Abstract: A leather-like sheet material usable for toecaps of footwear, is made by forming a mat of crimped continuous filaments, e.g. of nylon, polyethylene terephthalate, polyacrylonitrile, polythene, rayon or silk, consolidating the mat with a bonding agent, bonding a layer of woven (not knitted) fabric, e.g. of rayon, cotton or nylon, to one surface of the mat and applying a coating or preformed layer of resinous or elastomeric composition to the external surface of the fabric after or, preferably, before bonding it to the mat, the mat being formed by superposing layers of tensioned crimper yarns which, on relaxation and consequential re-crimping, intermingle in three dimensions.  The filaments of the mat may be multifilament yarns, which may be twisted, or twistless, and may be crimped by passing a heated and tensioned warp over a cooled knife edge, or may be chemically crimped.  The mat may be 10-50 mm. thick before and 0.5-2.5 mm. thick after consolidation.  The consolidating material may comprise, first a resinous material such as polythene or other polyolefin, which bonds the filaments at their crossing points, and second an elastomeric material which envelops the filaments. Suitable elastomeric materials, which may be applied in solution, comprise natural rubber, butyl rubber, butadiene/styrene or /acrylonitrile copolymers, polychloroprene or polyurethane rubber dissolved in methyl ethyl ketone.  Staple fibres, e.g. of poly-propylene, may be needled into one or both faces of the mat before consolidation. The resinous or elastomeric material applied to the fabric may comprise an acrylic polymer composition applied over a graft copolymer composition as in Specification 1,105,481.  In Examples (II) a web of crimped nylon yarns made as in the parent Specification was combined by needle-punching with a lightly needle-punched web of staple polypropylene fibres and the combined web was impregnated on a moving belt, with an aqueous dispersion comprising natural rubber, sulphur, lamp black, potassiumoleate solution, zinc oxide, ammonium chloride and curing ingredients, the impregnated web being pressed to remove surplus liquid and dried in an oven at 60 DEG C.  Batches of a copolymer latex, and a similar latex containing pigments, were prepared from t-butyl hydroperoxide and methyl methyacrylate, oleic acid, water, and rubber latex to which was added with stirring an aqueous solution of tetra ethylene pertamine, and were used, unpigmented, to secure to one face of a close woven rayon fabric a sheet of rubber made by coating with a rubber latex a moving belt coated with a saturated calcium chloride solution containing dodecyl pyridinium chloride, and removing the coagulated sheet.  The unpigmented copolymer latex was also used to secure the untreated face of the fabric to the dried fibrous web, and to spray-coat the rubber coating on the fabric, the latter then being lightly textured by pressing against a sand-blasted steel plate, or being embossed before combining with the fibrous web, and finally being treated, as with leather, by spraying with finishing compositions or "plating" IV.  A film of a compounded rubber latex containing a polyacrylate thickener, spread on a moving belt negatively embossed with a leather grain pattern, was adhered to a woven fabric after drying, the embossed rubber surface was spray-coated with an unpigmented rubber/methyl methacrylate copolymer latex and the product cured in an air oven at 120 DEG C and laminated to a rubber latex-impregnated fibrous web made by needle-punching carded polypropylene staple fibre layers to each side of a web of crimped nylon yarn and splitting into two layers after impregnation and drying, lamination being effected by a rubber/methyl methacrylate copolymer latex.  The embossed fabric surface was sprayed with acrylate and nitrocellulose finishes.