| 摘要 |
A composite material composing a fibrous constituent and a flexible or rigid polyurethane foam constituent is made by introducing into an assembly of fibres first a liquid composition representing one part of a polyurethane-foam-forming mixture and subsequently a vapour representing the complementary part of the polyurethane-foam-forming mixture, the vapour comprising at least one ingredient necessary for the polyurethane foam reaction, and then allowing the liquid composition and the vapour to react and form a polyurethane foam within the assembly of fibres. The fibrous assembly may be a matted web of crimped continuous nylon 66 fibres, a knitted stretch fabric of bulked nylon 66 yarn or a woollen blanket material. The assembly may be needled before impregnation and may be compressed or moulded during or just after foaming. The vapour may comprise steam or an amine catalyst, e.g. triethylamine or N-methyl-morpholine. The fibrous assembly carrying the liquid composition may be suspended or supported in a vessel containing the vapour. Alternatively, the vapour may be formed in situ from the liquid phase of the substance in question. The liquid composition may comprise a liquid reaction product of an organic polyiso(thio)cyanate and an organic compound having two or more isocyanate-reactive groups, this reaction product still having -NCO (or -NCS) groups available for reaction. The liquid composition may take the form of a solution of the active ingredients in an indifferent solvent, e.g. methyl ethyl ketone, into which the fibrous assembly is dipped. Examples are given in which the following substances are mentioned as ingredients of the liquid composition: liquid urethane rubber, 2:4-tolylene diisocyanate, 2:6-tolylene diisocyanate, a mixture of trimethylolpropane and hexanetriol, a solution of triethylene diamine in dry acetate, water-soluble silicone, trimethylopropane predissolved in methyl ethyl ketone, stannous octoate, and a solution of triethylene diamine in polypropylene glycol diol. The liquid composition may be spread on to one surface of the fibrous assembly with subsequent application of a doctor blade. The liquid is evenly distributed throughout the assembly by mangling during which the assembly is held between two polyethylene or polypropylene films. To produce an artificial leather having surfaces corresponding to the "grain" and "flesh" surfaces of natural leather, the fibrous assembly may comprise two fibrous webs superimposed one upon the other and the structure obtained when the polyurethane-foam-forming reaction has taken place may then be separated into two layers corresponding to the individual two webs; the layers obtained may be treated again individually by the method of the invention. Alternatively, the assembly of fibres is moulded during formation between an impervious surface and a porous surface. |
