Water soluble or dispersible polyurethanes, a process for their preparation and their use for coating substrates

Claim 2

A water-soluble or dispersible polyurethane containing about 0.5 to 30% by weight, based on the weight of the polyurethane, of chemically incorporated, hydrophilic ethylene oxide units arranged in lateral and/or terminal polyether chains to said polyurethane. and about 0.1 to 120 milliequivalents, per 100 g of solids content, of chemically incorporated carboxylate groups corresponding to the formula ##STR8## wherein R denotes an alkyl group with 1 to 4 carbon atoms and said hydrophilic ethylene oxide units and said carboxylate groups are present in an amount sufficient to ensure the solubility or dispersibility of said polyurethane in water.

Claim 3

The polyurethane of claim 1 wherein said alkyl group is a methyl group.

Claim 4

A process for the preparation of a water-soluble or dispersible polyurethane which comprises (a) an organic polyisocyanate with (b) an organic compound having a molecular weight of 300 to about 5000 and at least two isocyanate reactive groups, (c) a chain lengthening agent or cross-linking agent comprising a compound having a molecular weight of 32 to 299 and at least two isocyanate reactive groups, (d) a component containing ethylene oxide units within polyether chains comprising a member selected from the group consisting of (1) diisocyanates having lateral polyether chains containing ethylene oxide units and compounds containing isocyanate reactive groups which are difunctional in isocyanate polyaddition reactions and having lateral polyether chains containing ethylene oxide units, (2) monoisocyanates having polyether chains containing ethylene oxide units and compounds containing one isocyanate reactive group which are monofunctional in isocyanate polyaddition reactions and having polyether chains containing ethylene oxide units, and (3) mixtures of (1) and (2), (e) a dihydroxymonocarboxylic acid corresponding to the formula ##STR9## wherein R is an alkyl group having 1 to 4 carbon atoms, (f) optionally an organic compound which contains one isocyanate reactive group, is monofunctional in isocyanate polyaddition reactions and is free from ethylene oxide units, in at least one stage at an equivalent ratio of isocyanate groups to isocyanate reactive groups of about 0.8:1 to 2:1, conducting at least a portion of the last stage of said reaction in the presence of an isocyanate inert, water-miscible solvent to produce a polyurethane having an isocyanate group content of 0 to about 10% by weight and subsequently converting at least a portion of the carboxyl groups present to carboxylate groups with ammonia, said starting materials being selected such that said polyurethane contains about 0.5 to 30% by weight, based on the solids content, of chemically incorporated hydrophilic ethylene oxide units arranged in lateral and/or terminal polyether chains and about about 0.1 to 120 milliequivalents of carboxylate groups per 100 g of solids content, wherein said hydrophilic ethylene units and said said carboxylate groups are present in an amount sufficient to ensure the dispersibility or solubility of said polyurethane.

Claim 5

A process for the preparation of a water-soluble or dispersible polyurethane which comprises (a) an organic polyisocyanate with (b) an organic compound having a molecular weight of 300 to about 5000 and at least two isocyanate reactive groups, (c) a chain lengthening agent or cross-linking agent comprising a compound having a molecular weight of 32 to 299 and at least two isocyanate reactive groups, (d) a component containing ethylene oxide units within polyether chains comprising a member selected from the group consisting of (1) diisocyanates having lateral polyether chains containing ethylene oxide units and compounds containing isocyanate reactive groups which are difunctional in isocyanate polyaddition reactions and having lateral polyether chains containing ethylene oxide units, (2) monoisocyanates having polyether chains containing ethylene oxide units and compounds containing one isocyanate reactive group which are monofunctional in isocyanate polyaddition reactions and having polyether chains containing ethylene oxide units, and (3) mixtures of (1) and (2), (e) a dihydroxymonocarboxylic acid corresponding to the formula ##STR9## wherein R is an alkyl group having 1 to 4 carbon atoms, (f) optionally an organic compound which contains one isocyanate reactive group, is monofunctional in isocyanate polyaddition reactions and is free from ethylene oxide units, in at least one stage at an equivalent ratio of isocyanate groups to isocyanate reactive groups of about 0.8:1 to 2:1, conducting at least a portion of the last stage of said reaction in the presence of an isocyanate inert, water-miscible solvent to produce a polyurethane having an isocyanate group content of 0 to about 10% by weight and subsequently converting at least a portion of the carboxyl groups present to carboxylate groups with ammonia, said starting materials being selected such that said polyurethane contains about 0.5 to 30% by weight, based on the solids content, of chemically incorporated hydrophilic ethylene oxide units arranged in lateral and/or terminal polyether chains and about about 0.1 to 120 milliequivalents of carboxylate groups per 100 g of solids content, wherein said hydrophilic ethylene units and said said carboxylate groups are present in an amount sufficient to ensure the dispersibility or solubility of said polyurethane.

Claim 6

The process of claim 3, wherein said ammonia is in the form of an aqueous solution.

Claim 7

The process of claim 3, wherein R is a methyl group.

Claim 8

The process of claim 4, wherein R is a methyl group.

Claim 9

The process of claim 3, which comprises adding water to said solution before, during or after the addition of ammonia and optionally subsequently removing at least a portion of said solvent by distillation.

Claim 10

The process of claim 6, which comprises adding water to said solution before, during or after the addition of ammonia and optionally subsequently removing at least a portion of said solvent by distillation.

Claim 11

A coated substrate prepared from the water-soluble or dispersible polyurethane of claim 1.