Water vapor permeable sheet material

A process for making a water vapour permeable soft flexible material suitable for use as the upper of a shoe in place of leather which comprises depositing a layer of coagulable elastomeric polymer fleshcoat composition on a porous support to form the fleshcoat layer, prior to coagulation depositing a layer of coagulable elastomeric polymer substrate composition on top of the layer of fleshcoat composition and a layer of coagulable elastomeric topcoat composition on top of the layer of substrate composition, and then coagulating the composite material to an integrally adhered microporous three-layer structure free from fibrous reinforcement, at least the substrate composition and at least one of the fleshcoat or topcoat compositions containing a removable particulate filler, the filler in the said fleshcoat or topcoat compositions having an average particle size smaller than that used in the substrate composition, said compositions being such and being deposited in such thickness as to produce a product which is 0.8 to 2.0 mm thick, free from fibrous reinforcement, and having an elongation at break in excess of 200%, comprising a strength imparting porous elastomeric polymer substrate layer disposed between a porous elastomeric polymer fleshcoat layer and a porous elastomeric polymer topcoat layer, the substrate layer having a higher density than the fleshcoat or topcoat layers and being thicker than either the fleshcoat or the topcoat layers the thickness of each of said fleshcoat and topcoat layers being 10 to 95% of the thickness of said substrate layer and the combined thickness of the fleshcoat and topcoat layers being in the range 30 to 175% of the thickness of the substrate layer.