Patent GB-960360-A (GB)
Title: Improvements in or relating to the manufacture of artificial leather
Inventor: AOKI TOMOO
IPC: D06N3/00
Filed: 1963-03-22
Abstract: An artificial leather comprises a resinous surface layer up to 0,03 mm. thick and having a tensile recovery of up to 92% for a 20% elongation and a Young's coefficient of from 3 to 30 Kg./mm.2; a resinous intermediate layer from 0,05 to 10 mm. thick, inflated with pores to a volume which is from 1,2 to 4,0 times as large as the volume of the non-inflated layer and having a compression load deflection of from 100 to 800 g./cm.2 for a 25% reduction in the thickness thereof, the intermediate layer comprising at least one member selected from synthetic resins and artificial and natural rubbers; and a supporting layer having an elongation capable of imparting the required compression distortions to the intermediate and surface layers when crumpled; one face of the intermediate layer being securely joined to a face of the supporting layer and the other face to the surface layer, the artificial leather being crumpled during manufacture in a manner such that the physical distortions generated in the intermediate layer during the crumpling are permanently ingrained in the surface layer.  The three layers may be prepared separately and laminated, or the intermediate layer containing a blowing agent and surface layer may be coated on to the supporting layer, the intermediate layer being inflated in situ.  The supporting layer may be woven or unwoven fabric or a knitted material of, for example, a polyamide, polyacrylonitrile or a copolymer thereof, polypropylene, polyethylene, polyvinyl acetal, polyvinyl chloride, polyvinylidene chloride, polyester, viscose rayon, cellulose acetate, cotton, silk, wool, or paper. The intermediate layer may be prepared from one or more synthetic resins, e.g. a polyamide, natural or artificial rubber such as butadiene-acrylonitrile, butadiene-styrene, neoprene or urethane-rubbers, polypropylene, polyethylene, polyvinyl chloride or a polyurethane.  The intermediate layer may comprise 100 parts by weight polyvinyl chloride having a polymerization of the order of from 800 to 2000, from 0 to 40 parts by weight of butadiene rubber and from 30 to 100 parts by weight plasticizer; or may be formed from a polyurethane prepared by reacting a polyester or a polyether, having a hydroxyl value from 40 to 60 and a molecular weight of from 1800 to 4000, with an aromatic diisocyanate in an NCO/OH molar ratio of from 0,9 to 1,15 : 1.  The surface layer may be prepared from solvent-soluble copolyamides, N-alkoxymethyl polyamides in which there is from 18 to 40% alkoxy methylation, linear polyurethanes, polyesters, polyvinyl chloride, chlorosulphonated polyethylene, or polyethylene prepared under reduced pressure.  The surface layer may comprise a copolymer of from 30 to 70 mols of 6-nylon and from 70 to 30 mols of 6,6-nylon; from 20 to 40 mols each of 6-nylon, 6,6-nylon and 6,10-nylon; or an N-alkoxymethyl polyamide having from 14 to 35 mol per cent alkoxymethylation in which the alkoxy groups have from 1 to 5 carbon atoms; a polyurethane prepared by reacting a polyester or a polyether having a hydroxyl value of from 50 to 80 and a molecular weight of from 1400 to 3400 with an aromatic diisocyanate in an NCO/OH molar ratio of from 0,9 to 1,15 : 1; resins such as polyacrylonitrile can be employed with a polyurethane.  A nonporous protective coating up to 0,1 mm. thick and having a Young's coefficient of from 1 to 13 kg./mm.2 may be interposed between the surface and intermediate layers, the layer p  being formed from a synthetic resin, or a natural or synthetic rubber.  Depending on the components of the surface layer, the crumpling may be carried out at room temperature, in a hot bath or in a liquid vapour having no tendency to melt or dissolve the resin components of the surface layer.