Aqueous polyurethane-urea dispersion
The present invention relates to an aqueous dispersion based on polyurethane-urea, a composition comprising the same, and a use of the same in a coating agent, a sealant and an adhesive. The aqueous polyurethane-urea dispersion comprises a polyurethane-urea dispersed therein having sulfonate and/or carboxylate groups and lateral carboxyl groups, wherein the amount of said sulfonate and or carboxylate groups is 1.5 to 15 mmol/100 g; said lateral carboxyl is introduced by an aminocarboxylic acid having an amino functionality of greater than 1; the amount of said lateral carboxyl is 1.5 to 9.5 mmol/100 g, based on the polyurethane-urea solid components. Compared with the prior art, the composition of the polyurethane-urea based aqueous dispersion and a carboxyl reactive cross-linking agent provided by the present invention has a good cross-linking property and an excellent heat-resistance, which is not prone to come unglued when being exposed to heat.
1. An aqueous polyurethane-urea dispersion, comprising a polyurethane-urea dispersed therein having sulfonate and/or carboxylate groups and lateral carboxyl groups, wherein an amount of said sulfonate and/or carboxylate groups is 3.2 to 10 mmol/100 g; said lateral carboxyl groups are introduced by an aminocarboxylic acid having an amino functionality of greater than 1; an amount of said lateral carboxyl groups is 1.5 to 5 mmol/100 g, based on the polyurethane-urea solid components, wherein said composition further comprises a cross-linking agent containing carboxyl reactive groups selected from carbodiimides compound, wherein the molar ratio between carbodiimide groups of said carbodiimides compound and the lateral carboxyl groups of the aqueous polyurethane-urea dispersion is 2 to 5, and wherein said aminocarboxylic acid has an amino functionality of 2.
2. The aqueous polyurethane-urea dispersion according to claim 1 , wherein said polyurethane-urea is prepared by comprising following components:
A) at least one polyol component having a number-average molecular weight of 400 to 5000 Daltons and a hydroxyl functionality of not less than 1.9;
B) optionally at least one polyol component having a number-average molecular weight of 62 to 399 Daltons;
C) at least one diisocyanate or polyisocyanate component;
D) at least one aminocarboxylic acid having an amino functionality of greater than 1; and
E) at least one amino compound having sulfonate and/or carboxylate radicals.
3. The aqueous polyurethane-urea dispersion according to claim 1 , wherein said aminocarboxylic acid is selected from lysine.
4. The aqueous polyurethane-urea dispersion according to claim 1 , wherein said aqueous dispersion has a pH value of 6 to 9.
5. A composition comprising the aqueous polyurethane-urea dispersion according to claim 1 .
6. The composition according to claim 5 , wherein said composition is a coating, an adhesive or a sealant.
7. An article, comprising a substrate and the composition according to claim 5 applied thereon.
8. The article according to claim 7 , wherein said substrate is selected from rubber, plastics, paper, cardboards, timbers, textiles, metals, alloys, fabrics, fibers, artificial leathers, leathers or inorganic materials.