Aqueous polyurea dispersions and their use for preparing coatings with excellent hydrolytic and thermal stability

Abstract

The present invention relates to aqueous dispersions of polyureas containing hydantoin groups (calculated as C.sub.3 N.sub.2 O.sub.2, MW 96) in an amount of 1 to 40% by weight, based on resin solids. The present invention also relates to the use of these dispersions for preparing coatings having excellent hydrolytic and thermal stability.

Description

Claims

1. An aqueous dispersion of a polyurea containing hydantoin groups (calculated as C.sub.3 N.sub.2 O.sub.2, MW 96) in an amount of 1 to 40% by weight, based on resin solids.

2. The dispersion of claim 1 wherein said polyurea contains 10 to 120 milliequivalents per 100 grams of polyurea of chemically incorporated anionic groups and up to 10% by weight, based on the weight of said polyurea, of lateral and/or terminal hydrophilic chains containing ethylene oxide units.

3. The dispersion of claim 2 wherein at least about 80% of said anionic groups are carboxylate groups neutralized with tertiary amines.

4. An aqueous polyurea dispersion wherein the polyurea contains 1 to 40% by weight, based on the weight of the polyurea, of hydantoin groups (calculated as C.sub.3 N.sub.2 O.sub.2, MW 96) and wherein the polyurea is based on the reaction product of

a) an NCO prepolymer containing 1 to 40% by weight, based on the weight of said polyurea, of hydantoin groups (calculated as C.sub.3 N.sub.2 O.sub.2, MW 96) with

b) an isocyanate-reactive component containing amino groups.

5. The dispersion of claim 4 wherein said polyurea contains 10 to 120 milliequivalents per 100 grams of polyurea of chemically incorporated anionic groups and up to about 10% by weight, based on the weight of said polyurea, of lateral and/or terminal hydrophilic chains containing ethylene oxide units.

6. The dispersion of claim 5 wherein at least about 80% of said anionic groups are carboxylate groups neutralized with tertiary amines.