Ionic liquid catalysts in sulfur-containing polymer compositions

Patent metadata

Field	Value
Publication number	US-10035926-B2
Application number	US-201615135587-A
Country	US
Kind code	B2
Filing date	Apr 22, 2016
Priority date	Apr 22, 2016
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

Compositions comprising thiol-terminated sulfur-containing prepolymers, curing agents reactive with the thiol-terminated sulfur-containing prepolymers, and ionic liquid catalysts, useful in aerospace sealant applications are disclosed. The use of ionic liquid catalysts provides curable sealant compositions having an extended working time and a rapid cure rate.

First claim

What is claimed is:

1. A composition comprising:
a thiol-terminated sulfur-containing prepolymer;
a curing agent comprising two or more terminal groups reactive with thiol groups; and
an ionic liquid catalyst.

2. The composition of claim 1 , wherein the ionic liquid catalyst comprises an imidazolium ionic liquid catalyst.

3. The composition of claim 1 , wherein the ionic liquid catalyst comprises 1-butyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium ethyl sulfate, or a combination thereof.

4. The composition of claim 1 , wherein the ionic liquid catalyst comprises a controlled release ionic liquid catalyst.

5. The composition of claim 1 , wherein the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether, a thiol-terminated polysulfide, a thiol-terminated sulfur-containing polyformal, or a combination of any of the foregoing.

6. The composition of claim 1 , wherein the terminal groups reactive with thiol groups comprise thiol groups, epoxy groups, or Michael acceptor groups.

7. The composition of claim 1 , wherein the curing agent comprises a polythiol, a polyepoxide, or a polyfunctional Michael acceptor.

8. The composition of claim 1 , further comprising a primary catalyst.

9. The composition of claim 8 , wherein the composition comprises from 0.01 wt % to 1 wt % of the ionic liquid catalyst, wherein wt % is based on the total solids weight of the composition.

10. The composition of claim 8 , wherein the primary catalyst comprises an oxidizing agent.

11. The composition of claim 8 , wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polysulfide;
the curing agent comprises a thiol-terminated polysulfide; and
the primary catalyst comprises an oxidizing agent.

12. The composition of claim 8 , wherein the primary catalyst comprises an amine catalyst.

13. The composition of claim 8 , wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether;
the curing agent comprises a polyepoxide; and
the primary catalyst comprises an amine.

14. The composition of claim 8 , wherein the curing agent comprises a polyfunctional Michael acceptor.

15. The composition of claim 8 , wherein,
the thiol-terminated sulfur-containing prepolymer comprises a thiol-terminated polythioether;
the curing agent comprises a comprises a polyfunctional Michael acceptor; and
the primary catalyst comprises an amine.

16. The composition of claim 1 , formulated as a sealant.

17. A cured sealant prepared from the composition of claim 16 .

18. A part comprising the cured sealant of claim 17 .

19. A method of sealing a part, comprising:
applying the composition of claim 16 to at least a portion of a surface of a part; and
curing the applied composition to seal the part.

20. An aerospace vehicle comprising the cured sealant of claim 17 .

21. The composition of claim 1 , wherein the ionic liquid catalyst comprises a combination of a cation and an anion, wherein,
the cation comprises a mono-, di-, and tri-substituted imidazolium, a substituted pyridinium, a substituted pyrrolidinium, a tetraalkyl phosphonium, a tetraalkyl ammonium, a guanidinium, a isouronium; or a thiouronium; and
the anion comprises a chloride; a bromide; an iodide, a tetrafluoroborate, a hexafluorophosphate, a bis(trifluoromethylsulfonyl)imide, a tris(pentafluoroethyl)trifluorophosphate, a trifluoromethanesulfonate, a trifluoroacetate, a methylsulfate, a octylsulfate, a thiocyanate, organoborates, and a p-toluenesulfonate.

22. The composition of claim 1 , wherein the ionic liquid catalyst comprises a combination of a cation and an anion, wherein,
the cation comprises an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, a phosphonium cation, an ammonium cation, a sulfonium cation, or a combination of any of the foregoing; and
the anion comprises an alkylsulfate anion, a tosylate anion, a methane sulfonate anion, or a combination of any of the foregoing.

23. The composition of claim 1 , wherein the ionic liquid catalyst comprises an imidazolium-based ionic liquid catalyst, a pyridinium-based ionic liquid catalyst, a pyrrolidinium-based ionic liquid catalyst, an ammonium-based ionic liquid catalyst, or a phosphonium-based ionic liquid catalyst.

24. The composition of claim 1 , wherein the ionic liquid catalyst comprises 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium methane sulfonate, methyl-tri-n-butylammonium methyl sulfate, 1,2,4-trimethylpyrazolium methylsulfate, 1-ethyl-2,3-di-methylimidazolium ethylsulfate, 1,2,3-trimethyl-imidazolium methylsulfate, methylimidazolium chloride, methylimidazolium hydrogen sulfate, 1-ethyl-3-methylimidazolium hydrogensulfate, 1-ethyl-3-methylimidazolium tetrachloroaluminate, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-butyl-3-methylimidazolium tetrachloroaluminate, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-3-methylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium thiocyanate, or a combination of any of the foregoing.

25. The composition of claim 1 , wherein, the ionic liquid catalyst is the only catalyst in the composition.

26. The composition of claim 1 , wherein,
the ionic liquid catalyst is the only catalyst in the composition;
the composition comprises from 1 wt % to 15wt %; and
wt % is based on the total solids weight of the composition.

27. The composition of claim 1 , wherein,
the composition comprises a primary catalyst; and
the composition comprises from 0.05 wt % to 3 wt % of the ionic liquid catalyst; and
wt % is based on the total solids weight of the composition.

Assignees

• Prc Desoto Int Inc
• Prc—Desoto Int Inc

Inventors

• Toolis Amy Liane
• Anderson Lawrence G
• Sawders-Georgic Brianne N

Classifications

• C09D181/04 Primary

  Polysulfides · CPC title

• C09K2200/0682

  Containing sulfur · CPC title

• C07D233/56

  with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms · CPC title

• C09K3/1006 Primary

  characterised by the chemical nature of one of its constituents · CPC title

• C09J181/04

  Polysulfides · CPC title