Coating materials containing PUR dispersions and solvents and their use for the preparation of water vapor permeable PUR coatings

A coating composition comprising

• a) about 40 to 70% of an aqueous polyurethane dispersion which has a solids content of about 20 to 60% and wherein the polyurethane is rendered hydrophilic by a substituent which comprises a member selected from the group consisting of carboxylate groups, sulphonate groups, pendant polyether chains having oxyethylene units, terminal polyether chains having oxyethylene units and mixtures thereof,
• b) about 0.1 to 5% by weight of a water-soluble, polymeric thickening agent for aqueous polyurethane dispersions which is not a polyurethane, is free from carboxyl groups and comprises a member selected from the group consisting of polyvinylpyrrolidone polymers, copolymers based on polyvinylpyrrolidone and polyethylene glycols and mixtures thereof,
• c) about 25 to 70% by weight of water-immiscible organic solvent which is not a solvent for the polyurethane dispersed in water, has a boiling point up to 220.degree. C. and comprises a member selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons and mixtures thereof,
• d) about 0.1 to 5% by weight of a cross-linking agent for the polyurethane dispersed in water which does not contain free isocyanate groups and comprises a member selected from the group consisting of blocked polyisocyanates, urea resins, melamine resins, urea/melamine resins, polyepoxides, polyaziridines, polycarbodiimides and mixtures thereof, and
• e) about 1 to 3% by weight of a hydrophilic polyisocyanate which promotes the adhesion of the coating composition to substrates, is a cross-linking agent for the polyurethane dispersed in water, has an NCO content of about 5 to 30% by weight and is prepared by reacting a polyisocyanate containing aliphatically- and/or cycloaliphatically-bound isocyanate groups with an ethylene oxide/propylene oxide polyether having an ethylene oxide content of at least 50% by weight,
• wherein the sum of the percentages a)+b)+c)+d)+e) is 100.

A water vapor permeable coated textile or leather substrate wherein the coating is based on a coating composition comprising

• a) about 20 to 90% of an aqueous polyurethane dispersion which has a solids content of about 20 to 60% and wherein the polyurethane is rendered hydrophilic by a substituent which comprises a member selected from the group consisting of carboxylate groups, sulphonate groups, pendant polyether chains having oxyethylene units, terminal polyether chains having oxyethylene units and mixtures thereof,
• b) about 0.1 to 5% by weight of a water-soluble, polymeric thickening agent for aqueous polyurethane dispersions which is not a polyurethane and which is free from carboxyl groups,
• c) about 3 to 80% by weight of water-immiscible organic solvent which is not a solvent for polyurethane dispersed in water and which has a boiling point up to 250.degree. C.,
• d) about 0.1 to 5% by weight of a cross-linking agent for the polyurethane dispersed in water which does not contain free isocyanate groups and
• e) about 0.1 to 5% of a hydrophilic polyisocyanate which promotes the adhesion of the coating composition to substrates and is a cross-linking agent for the polyurethane dispersed in water,
• wherein the sum of the percentages a)+b)+c)+d)+e) is 100.