Polyisocyanates containing allophanate and silane groups

1. A process for preparing polyisocyanates containing allophanate groups comprising reacting

A) at least one hydroxyurethane and/or hydroxyamide containing silane groups obtained from the reaction of aminosilanes with cyclic carbonates and/or lactones;

with a molar excess amount, based on the NCO-reactive groups of A), of

B) at least one diisocyanate having aliphatically, cycloaliphatically, araliphatically, and/or aromatically attached isocyanate groups; and

optionally subsequently removing unreacted excess diisocyanate.

2. The process of claim 1 , wherein A) comprises a reaction product of aminosilanes of general formula (I)

wherein

R 1 , R 2 and R 3 are, identically or differently, a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic, or optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms optionally comprising up to 3 heteroatoms from the series oxygen, sulphur, and nitrogen;

X is a linear or branched organic radical having at least 2 carbon atoms optionally comprising up to 2 imino (—NH—) groups; and

R 4 is hydrogen, or a saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic, or optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms, or a radical of formula

wherein R 1 , R 2 , R 3 , and X are as defined above,

with cyclic carbonates and/or lactones.

3. The process of claim 1 , wherein A) comprises a reaction product of aminosilanes of general formula (I)

wherein

R 1 , R 2 and R 3 are, identically or differently, a saturated, linear or branched, aliphatic or cycloaliphatic radical having up to 6 carbon atoms optionally comprising up to 3 oxygen atoms;

X is a linear or branched alkylene radical having 2 to 10 carbon atoms optionally comprising up to 2 (—NH—) imino groups; and

R 4 is hydrogen, a saturated, linear or branched, aliphatic or cycloaliphatic radical having up to 6 carbon atoms, or a radical of formula

wherein R 1 , R 2 , R 3 , and X are as defined above,

with cyclic carbonates and/or lactones.

4. The process of claim 1 , wherein A) comprises a reaction product of aminosilanes of the general formula (I)

wherein

R 1 , R 2 and R 3 are each alkyl radicals having up to 6 carbon atoms and/or alkoxy radicals which contain up to 3 oxygen atoms, with the proviso that at least one of R 1 , R 2 and R 3 is an alkoxy radical;

X is a linear or branched alkylene radical having 3 or 4 carbon atoms; and

R 4 is hydrogen, a methyl radical, or a radical of the formula

wherein R 1 , R 2 , R 3 , and X are as defined above,

with cyclic carbonates and/or lactones.

5. The process of claim 1 , wherein A) comprises a reaction product of aminosilanes of the general formula (I)

wherein

R 1 , R 2 and R 3 are, identically or differently methyl, methoxy, or ethoxy radical, with the proviso that at least one of R 1 , R 2 and R 3 is a methoxy or ethoxy radical;

X is a propylene (—CH 2 —CH 2 —CH 2 —) radical; and

R 4 is hydrogen, a methyl radical, or a radical of formula

wherein R 1 , R 2 , R 3 , and X are as defined above,

with cyclic carbonates and/or lactones.

6. The process of claim 1 , wherein A) comprises reaction products of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, and/or 3-aminopropylmethyldiethoxysilane with cyclic carbonates and/or lactones.

7. The process of claim 1 , wherein A) comprises reaction products of aminosilanes with ethylene carbonate and/or propylene carbonate.

8. The process of claim 1 , wherein A) comprises reaction products of aminosilanes with β-propiolactone, γ-butyrolactone, γ-valerolactone, γ-caprolactone, and/or ε-caprolactone.

9. The process of claim 1 , wherein B) comprises diisocyanates having aliphatically and/or cycloaliphatically attached isocyanate groups.

10. The process of claim 1 , wherein B) comprises 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 2,4′- and/or 4,4′-diisocyanatodicyclohexylmethane, or mixtures thereof.

11. The process of claim 1 , wherein the reaction is carried out in the presence of a catalyst which accelerates the formation of allophanate groups.

12. The process of claim 11 , wherein said catalyst comprises zinc carboxylates and/or zirconium carboxylates.

13. The process of claim 11 , wherein said catalyst comprises zinc(II) n-octanoate, zinc(II) 2-ethyl-1-hexanoate, zinc(II) stearate, zirconium(IV) n-octanoate, zirconium(IV) 2-ethyl-1-hexanoate, and/or zirconium(IV) neodecanoate.

14. A polyisocyanate containing allophanate groups prepared by the process of claim 1 .

15. The polyisocyanate containing allophanate groups of claim 14 , wherein said polyisocyanate containing allophanate groups is blocked with blocking agents.

16. A coating composition comprising the polyisocyanate carrying allophanate groups of claim 14 .

17. A substrate coated with the coating composition of claim 16 .