Isocyanates containing uretdione groups
View Patent ↗The invention relates to novel compounds containing uretdione groups, to a process for preparing them by dimerizing aliphatic and/or cycloaliphatic isocyanates containing exclusively secondary and/or tertiary isocyanate groups and also to the use of uretdione polyisocyanates obtainable by this process from diisocyanates containing exclusively secondary and/or tertiary isocyanate groups as a starting component for polyurethane polymers, in particular as an isocyanate component in the preparation of uretdione powder coating crosslinkers.
1. A process for dimerizing compounds containing exclusively secondary and/or tertiary isocyanate groups comprising dimerizing said compounds in the presence of a saltlike oligomerization catalyst containing one or both of 1,2,3-triazolate structures and 1,2,4-triazolate structures in the anion of the catalyst.
2. The process according to claim 1 , wherein the anion of the saltlike oligomerization catalyst contains one or both triazolate structures of the general formulas (I) and (II)
wherein
R 1 ,R 2 ,R 3 and R 4 are independently identical or different radicals selected from a hydrogen atom; a halogen atom selected from fluorine, chlorine and bromine; a nitro group; a saturated or unsaturated aliphatic or cycloaliphatic radical; an optionally substituted aromatic or araliphatic radical containing up to 20 carbon atoms and optionally up to 3 heteroatoms selected from oxygen, sulphur and nitrogen and optionally substituted by halogen atoms or nitro groups and where R 3 and R 4 in formula (II) together with the carbon atoms of the 1,2,3-triazolate five-membered ring also form optionally fused rings having 3 to 6 carbon atoms.
3. The process according to claim 2 , wherein the anion of the saltlike oligomerization catalyst compound contains the triazolate structures of general formula (I), wherein R 1 and R 2 are identical or different radicals selected from a hydrogen atom; a halogen atom selected from fluorine, chlorine and bromine; a nitro group; a saturated aliphatic or cycloaliphatic radical or an optionally substituted aromatic or araliphatic radical containing up to 12 carbon atoms and optionally up to 3 heteroatoms selected from oxygen, sulphur and nitrogen and can optionally be substituted by halogen atoms or nitro groups.
4. The process according to claim 2 , wherein the anion of the saltlike oligomerization catalyst compound contains the triazolate structure of general formula (II), wherein R 3 and R 4 are identical or different radicals selected from a hydrogen atom; a halogen atom selected from fluorine, chlorine and bromine; a nitro group; a saturated or unsaturated aliphatic or cycloaliphatic radical or an optionally substituted aromatic or araliphatic radical containing up to 12 carbon atoms and optionally up to 3 heteroatoms selected from oxygen, sulphur and nitrogen and can optionally be substituted by halogen atoms or nitro groups; and together with the carbon atoms of the 1,2,3-triazolate five-membered ring also form optionally fused rings having 3 to 6 carbon atoms.
5. The process according to claim 2 , wherein the anion of the saltlike oligomerization catalyst comprises one or more salts of compounds selected from 1,2,4-triazole, 1,2,3-triazole and 1,2,3-benzotriazole, and mixtures thereof.
6. The process according to claim 5 , wherein the oligomerization catalyst contain as cations one or more compounds selected from alkali metal ions, monovalent ammonium ions, and phosphonium cations of the general formula (III)
wherein
E is nitrogen or phosphorus, and
R 5 , R 6 , R 7 and R 8 are identical or different radicals selected from saturated aliphatic or cycloaliphatic radicals and optionally substituted aromatic or araliphatic radical having up to 18 carbon atoms.