Microfibrous fabric having a suede appearance, within the colour range of grey and black, with a high light fastness, and preparation method thereof

A process for the production of an artificial leather having a suede appearance, a color fastness to light, higher than or equal to 4, according to the method SAE J 1885 225.6 KJ/m2, and a color fastness to light not lower than 3, according to the method SAE J 1885 488.8 KJ/m2, said process comprising the following steps:

• a) spinning bi-component fibers of the “sea-island” type, in which the “island” component consists of a polyester and 0.05% to 2% by weight of carbon black and the “sea” component consists of a polymer immiscible with the island component;
• b) preparing a mono-layer felt by connecting the bi-component fibers through needle punching;
• c) impregnating the mono-layer felt with a polyurethane (PU) or a polyurethane dispersion (PUD) binder capable of withholding the “island” component during the subsequent elimination phase of the “sea” component;
• d) dissolving the “sea” component with an organic solvent to give a microfibrous intermediate product;
• e) impregnating the microfibrous intermediate product with an elastomeric matrix solution and/or dispersion comprising one or more polyurethanes and carbon black, the latter being present in a quantity of 0.02 to 6% by weight, with respect to the polyurethane, said polyurethane being made up of soft segments and hard segments, said soft segments consisting of at least one polyalkylene carbonate diol and at least one polyester diol;
• said hard segments consisting of urethane and/or ureic groups deriving from the reaction between free isocyanate groups and water;
• f) eliminating the organic solvent to give a raw semi-finished product;
• g) grinding the surface of the raw semi-finished product to yield ground raw semi-finished product having a suede appearance;
• and
• h) overdyeing the ground raw semi-finished product with dispersed dyes to obtain an artificial leather having a suede appearance, a color fastness to light higher than or equal to 4, according to the method SAE J 1885 225.6 KJ/m2, and a color fastness to light not lower than 3, according to the method SAE J 1885 488.8 KJ/m2.