Porous gels based on aromatic and cycloaliphatic amines

1. A porous gel, comprising:

a polyfunctional isocyanate,

a polyfunctional aromatic amine, and

a polyfunctional cycloaliphatic amine,

wherein the porous gel has a porosity of at least 70% by volume, and

the polyfunctional isocyanate, the polyfunctional aromatic amine, and the polyfunctional cycloaliphatic amine are present as polymeric or polymer-bound components.

2. The porous gel of claim 1 , wherein the porous gel is a xerogel.

3. The porous gel of claim 1 , comprising:

from 20 to 90% by weight of the polyfunctional isocyanate,

from 9.99 to 45% by weight of the polyfunctional aromatic amine, and

from 0.01 to 35% by weight of the polyfunctional cycloaliphatic amine,

wherein a sum of total percentages by weight of the polyfunctional isocyanate, the polyfunctional aromatic amine, and the polyfunctional cycloaliphatic amine is 100%.

4. The porous gel of claim 1 ,

wherein the polyfunctional cycloaliphatic amine comprises a compound comprising at least two amino groups of a structure comprising a ring,

the structure comprising a ring is of formula:

where R 1 to R 4 are each independently hydrogen or a linear or branched alkyl group having from 1 to 12 carbon atoms,

the ring is an optionally substituted cycloaliphatic ring, optionally joined to a further cycloaliphatic ring.

5. The porous gel of claim 1 ,

wherein the polyfunctional cycloaliphatic amine comprises a compound comprising at least two amino groups, each joined to an optionally substituted cyclohexyl ring, optionally joined directly or indirectly to a further, optionally substituted cyclohexyl ring.

6. The porous gel of claim 1 ,

wherein the polyfunctional cycloaliphatic amine comprises a compound of a structure:

and

R 1 to R 10 are each independently hydrogen or a linear or branched alkyl group having from 1 to 12 carbon atoms.

7. The porous gel of claim 1 ,

wherein the polyfunctional cycloaliphatic amine is 3,3′,5,5′-tetraalkyl-4,4′-diaminodicyclohexylmethane,

alkyl groups in the 3,3′,5 and 5′ positions each independently a linear or branched alkyl group having from 1 to 12 carbon atoms.

8. The porous gel of claim 1 , wherein the polyfunctional cycloaliphatic amine is 3,3′,5,5′-tetramethyl-4,4′-diaminodicyclohexylmethane.

9. The porous gel of claim 1 , wherein the polyfunctional aromatic amine consists of at least one polyfunctional aromatic amine selected from the group consisting of 4,4′-diaminodiphenylmethane, 2,4′-diaminodiphenylmethane, 2,2′-diaminodiphenylmethan, and oligomeric diaminodiphenylmethane.

10. The porous gel of claim 1 , wherein the polyfunctional aromatic amine comprises oligomeric diaminodiphenylmethane and has a functionality of at least 2.3.

11. The porous gel of claim 1 , wherein the polyfunctional isocyanate consists of at least one polyfunctional isocyanate selected from the group consisting of diphenylmethane 4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate, diphenylmethane 2,2′-diisocyanate, and oligomeric diphenylmethane diisocyanate.

12. The porous gel of claim 1 , wherein the polyfunctional isocyanate comprises oligomeric diphenylmethane diisocyanate and has a functionality of at least 2.5.

13. The porous gel of claim 1 ,

wherein the polyfunctional isocyanate comprises oligomeric diphenylmethane diisocyanate,

the polyfunctional aromatic amine comprises oligomeric diaminodiphenylmethane, and

a sum of a functionality of the polyfunctional isocyanate and of a functionality of the polyfunctional aromatic amine is at least 5.5.

14. The porous gel of claim 1 , wherein a volume-weighted mean pore diameter of the porous gel is at most 3 micrometers.

15. A process for preparing the porous gel of claim 1 , comprising:

providing the polyfunctional isocyanate and, separately therefrom, the polyfunctional aromatic amine and the polyfunctional cycloaliphatic amine, each in a solvent;

converting the polyfunctional isocyanate, the polyfunctional aromatic amine, and the polyfunctional cycloaliphatic amine in the presence of the solvent, to obtain a gel; and

drying the gel.

16. The process of claim 15 , wherein drying the porous gel comprises converting the solvent to a gas at a temperature and a pressure below a critical temperature and a critical pressure of the solvent.

17. A porous gel obtained by the process of claim 15 .

18. An insulating material, comprising the porous gel of claim 1 .

19. A vacuum insulation panel, comprising the porous gel of claim 1 .

20. The porous gel of claim 1 , wherein the porosity is at least 80% by volume.