Process for trimerising cycloaliphatic diisocyanates

Patent metadata

Field	Value
Publication number	US-9376403-B2
Application number	US-201313971018-A
Country	US
Kind code	B2
Filing date	Aug 20, 2013
Priority date	Aug 23, 2012
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

The invention relates to a process for preparing polyisocyanates containing isocyanurate groups by trimerising cycloaliphatic diisocyanates using a catalyst solution comprising at least one quaternary ammonium hydroxide, characterized in that the catalyst solution is metered in such that the reaction temperature is >90° C. and ≦140° C.

First claim

The invention claimed is:

1. A process for preparing a cycloaliphatic polyisocyanate containing isocyanurate groups comprising trimerizing a cycloaliphatic diisocyanate in the presence of a catalyst solution comprising at least one quaternary ammonium hydroxide in a reaction solution, wherein the catalyst solution is metered in to said reaction solution such that a reaction temperature greater than 90° C. and less than or equal to 140° C. is maintained.

2. The process of claim 1 , wherein the catalyst solution is metered in to said reaction solution such that a reaction temperature greater than 90° C. and less than or equal to 135° C. is maintained.

3. The process of claim 1 , wherein the catalyst solution is metered in to said reaction solution such that a reaction temperature greater than 90° C. and less than or equal to 120° C. is maintained.

4. The process of claim 1 , wherein the process is carried out continuously in one or more stirred tanks.

5. The process of claim 1 , wherein an isocyanate content is achieved corresponding to a degree of trimerisation of from 8 to 30%.

6. The process of claim 1 , wherein an isocyanate content is achieved corresponding to a degree of trimerisation of from 12 to 24%.

7. A continuous process for preparing a cycloaliphatic polyisocyanate containing isocyanurate groups comprising trimerizing a cycloaliphatic diisocyanate in the presence of a catalyst solution comprising at least one quaternary ammonium hydroxide in a stirred tank cascade with n stirred tanks, wherein, in at least n/2 or (n/2−0.5) tanks, the metered addition is such that the reaction temperature in at least n/2 or (n/2+0.5) tanks is greater than 90° C. and less than or equal to 140° C., where n/2 applies to an even number of tanks and (n/2−0.5) or (n/2+0.5) applies to an odd number of tanks and n is a whole number from 2 to 6.

8. The process of claim 7 , wherein an isocyanate content is achieved in the nth tank corresponding to a degree of trimerisation of from 8 to 30%.

9. The process of claim 7 , wherein an isocyanate content is achieved in the nth tank corresponding to a degree of trimerisation of from 12 to 24%.

10. The process of claim 1 , wherein the catalyst comprises from 0.001 to 2% by weight of quaternary ammonium hydroxide, based on the amount of diisocyanate.

11. The process of claim 1 , wherein the catalyst comprises from 0.005 to 1% by weight of quaternary ammonium hydroxide, based on the amount of diisocyanate.

12. The process of claim 1 , wherein the catalyst solution has a catalyst concentration of from 0.1 to 10% by weight, based on the catalyst solution.

13. The process of claim 1 , wherein the catalyst solution has a catalyst concentration of from 0.2 to 8% by weight, based on the catalyst solution.

14. The process of claim 1 , wherein the catalyst solution comprises at least one quaternary tetraalkylammonium hydroxide and/or a mixed quaternary tetraalkyl/aralkylammonium hydroxide and/or a quaternary tetraaralkylammonium hydroxide.

15. The process of claim 1 , wherein the catalyst solution comprises at least one quaternary trialkylaralkylammonium hydroxide.

16. The process of claim 14 , wherein the catalyst solution comprises at least one quaternary tetraalkylammonium hydroxide and/or one quaternary mixed tetraalkyl/aralkylammonium hydroxide, wherein the alkyl groups of said at least one quaternary tetraalkylammonium hydroxide and/or one quaternary mixed tetraalkyl/aralkylammonium hydroxide are not substituted with any hydroxyl groups.

17. The process of claim 14 , wherein the catalyst solution comprises a quaternary benzyltrialkylammonium hydroxide.

18. The process of claim 14 , wherein the catalyst solution comprises benzyltrimethylammonium hydroxide.

19. The process of claim 1 , wherein the cycloaliphatic diisocyanate comprises isophorone diisocyanate.

20. The process of claim 1 , wherein the trimerization is stopped chemically or thermally.

21. The process of claim 20 , wherein the trimerization is stopped chemically by adding an acidic compound, an acid, and/or an alkylating agent to the reaction solution.

22. The process of claim 1 , further comprising, in a downstream step, removing residual monomeric cycloaliphatic diisocyanate from the polyisocyanate by distillation.

23. The process of claim 1 , wherein the trimerization is stopped thermally.

Assignees

• Bayer Materialscience Ag
• Covestro Deutschland Ag

Inventors

• Halpaap Reinhard
• Schneider Mario
• Wilmes Oswald
• Werner Uwe

Classifications

• C08G18/1875

  containing ammonium salts or mixtures of secondary of tertiary amines and acids · CPC title

• C08G18/022

  the polymeric products containing isocyanurate groups · CPC title

• C08G18/755

  and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate · CPC title

• C08G18/092

  oligomerisation to isocyanurate groups · CPC title

• C07D251/34 Primary

  Cyanuric or isocyanuric esters · CPC title