Water-emulsifiable isocyanates with improved properties
A mixture of water-emulsifiable isocyanates is described. The mixture contains (A) at least one polyisocyanate (a), (B) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of less than 400 g/mol, (C) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of greater than 450 g/mol, and (D) optionally at least one emulsifier obtained by reacting a polyisocyanate with at least one compound (d) having at least one hydrophilic, non-isocyanate-reactive group and precisely one isocyanate-reactive group (group D2). The weight ratio of component (B) to component (C) in the mixture is from 30:70 to 70:30, preferably from 40:60 to 60:40.
1. A mixture, comprising
(A) at least one polyisocyanate (a),
(B) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a number average molecular weight of less than 400 g/mol,
(C) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a number average molecular weight of greater than 450 g/mol, and
(D) optionally at least one emulsifier obtained by reacting a polyisocyanate with at least one compound (d) having at least one hydrophilic, non-isocyanate-reactive group D1 and precisely one isocyanate-reactive group D2,
where a weight ratio of component (B) to component (C) is from 40:60 to 60:40.
2. The mixture according to claim 1 , wherein
the at least one polyisocyanate (a) comprises at least one polyisocyanate (a1) and at least one polyisocyanate (a2),
the at least one polyisocyanate (a1) is an isocyanurate and/or biuret of 1,6-diisocyanatohexane, and
the at least one polyisocyanate (a2) is an isocyanurate of 1 isophorone diisocyanate.
3. The mixture according to claim 1 , comprising in solvent-free form
70-95% by weight of component (A),
2.5-20% by weight of component (B),
2.5-20% by weight of component (C), and
0-15% by weight of component (D),
where a sum of (A), (B), (C) and (D) is 100% by weight.
4. The mixture according to claim 2 , comprising in solvent-free form
30-70% by weight of polyisocyanate (a1),
10-50% by weight of polyisocyanate (a2),
2.5-20% by weight of component (B),
2.5-20% by weight of component (C), and
0-15% by weight of component (D),
where a sum of (a1), (a2), (B), (C) and (D) is 100% by weight.
5. The mixture according to claim 1 , wherein the polyisocyanate in component (B) and/or component (C) comprises an isocyanurate and/or biuret of 1,6-hexamethylenediisocyanate and/or comprises an isocyanurate of isophorone diisocyanate.
6. The mixture according to claim 1 , wherein the polyether alcohol in component (B) and/or component (C) is obtained by reacting at least one saturated aliphatic alcohol having 1 to 4 carbon atoms in the alkyl radical with ethylene oxide, propylene oxide or a mixture thereof.
7. The mixture according to claim 1 , wherein the polyether alcohol in component (B) and/or component (C) is obtained by reacting methanol with ethylene oxide.
8. The mixture according to claim 1 , wherein the polyether alcohol in component (B) has a molecular weight ranging from 200 g/mol to 400 g/mol.
9. The mixture according to claim 1 , wherein the polyether alcohol in component (C) has a molecular weight ranging from 450 g/mol to 650 g/mol.
10. A polymer dispersion, comprising a mixture according to claim 1 .
11. A coating material, comprising the mixture according to claim 1 .
12. A process for coating a substrate, the processing comprising:
coating the substrate with a coating composition comprising the mixture according to claim 1 .
13. A coating material, comprising the polymer dispersion according to claim 10 .