Porous thermally insulating compositions containing hollow silica particles

Patent metadata

Field	Value
Publication number	US-10611902-B2
Application number	US-201815889543-A
Country	US
Kind code	B2
Filing date	Feb 6, 2018
Priority date	Feb 6, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A thermally insulating composition comprising hollow spherical silica particles and a coating of a material having a thermal conductivity of less than 0.3 W/m·K on surfaces of said silica particles. In particular embodiments, the low conductivity coating material may be a polymer, such as polystyrene or polyvinylpyrrolidone, or the low conductivity coating material may be a quaternary ammonium salt of the Formula (1), i.e., R1R2R3R4N+A−, with at least one of R1, R2, R3, and R4 being an alkyl group containing at least ten carbon atoms (and A− is a counter anion), or the low conductivity coating material may be phenyl-C61-butyric acid methyl ester covalently bound to the hollow spherical silica particles. Also described herein is a method of thermally insulating a surface by applying a coating of the thermally insulating composition, described above, onto the surface.

First claim

What is claimed is:

1. A thermally insulating composition comprising hollow spherical silica particles and a coating material having a thermal conductivity of no more than 0.3 W/m·K on surfaces of said hollow spherical silica particles, wherein said coating material is selected from at least one of the following:
(i) polymers selected from polystyrene or polyvinylpyrrolidinone;
(ii) quaternary ammonium salt having the following formula:

wherein R 1 , R 2 , R 3 , and R 4 are alkyl groups, with at least one of R 1 , R 2 , R 3 , and R 4 being an alkyl group having at least ten carbon atoms; and A − is a counter anion; and
(iii) phenyl-C61-butyric acid methyl ester that is covalently bound by an amide bond, in place of the ester group, via a linker to the surface of the hollow spherical silica particles.

2. The insulating composition of claim 1 , wherein said coating material is polystyrene.

3. The insulating composition of claim 1 , wherein said coating material is polyvinylpyrrolidone.

4. The insulating composition of claim 1 , wherein said coating material is said quaternary ammonium salt having the formula (1).

5. The insulating composition of claim 4 , wherein said quaternary ammonium salt contains a cetyltrimethylammonium portion.

6. The insulating composition of claim 1 , wherein said coating is material phenyl-C61-butyric acid methyl ester that is covalently bound by an amide bond, in place of the ester group, via a linker to the surface of the hollow spherical silica particles.

7. The insulating composition of claim 1 , wherein said hollow spherical silica particles have a mean particle size of up to 1000 nm.

8. The insulating composition of claim 1 , wherein said hollow spherical silica particles have a mean particle size of up to 500 nm.

9. The insulating composition of claim 1 , wherein said hollow spherical silica particles do not contain surface porosity.

10. The insulating composition of claim 1 , wherein said hollow spherical silica particles contain surface porosity.

11. The insulating composition of claim 10 , wherein said surface porosity is characterized by pores having a size of up to 50 nm.

12. The insulating composition of claim 10 , wherein said surface porosity is characterized by pores having a size of up to 10 nm.

13. The insulating composition of claim 10 , wherein said surface porosity is characterized by pores having a size of up to 5 nm.

14. The insulating composition of claim 10 , wherein said surface porosity is characterized by pores having a size of up to 1 nm.

15. A method of thermally insulating a surface, the method comprising applying a coating of a thermally insulating composition onto said surface, wherein said thermally insulating composition comprises hollow spherical silica particles and a coating material having a thermal conductivity of less than 0.3 W/m·K on surfaces of said hollow spherical silica particles, wherein said coating material is selected from at least one of the following:
(i) polymers selected from polystyrene or polyvinylpyrrolidinone;
(ii) quaternary ammonium salt having the following formula:

wherein R 1 , R 2 , R 3 , and R 4 are alkyl groups, with at least one of R 1 , R 2 , R 3 , and R 4 being an alkyl group having at least ten carbon atoms; and A − is a counter anion; and
(iii) phenyl-C61-butyric acid methyl ester that is covalently bound by an amide bond, in place of the ester group, via a linker to the surface of the hollow spherical silica particles.

16. The method of claim 15 , wherein said coating material is polystyrene.

17. The method of claim 15 , wherein said coating material is polyvinylpyrrolidone.

18. The method of claim 15 , wherein said coating material is said quaternary ammonium salt having the formula (1).

19. The method of claim 18 , wherein said quaternary ammonium salt contains a cetyltrimethylammonium portion.

20. The method of claim 15 , wherein said coating material is phenyl-C61-butyric acid methyl ester that is covalently bound by an amide bond, in place of the ester group, via a linker to the surface of the hollow spherical silica particles.

21. The method of claim 15 , wherein said hollow spherical silica particles have a mean particle size of up to 1000 nm.

22. The method of claim 15 , wherein said hollow spherical silica particles have a mean particle size of up to 500 nm.

23. The method of claim 15 , wherein said hollow spherical silica particles do not contain surface porosity.

24. The method of claim 15 , wherein said hollow spherical silica particles contain surface porosity.

25. The method of claim 24 , wherein said surface porosity is characterized by pores having a size of up to 50 nm.

26. The method of claim 24 , wherein said surface porosity is characterized by pores having a size of up to 10 nm.

27. The method of claim 24 , wherein said surface porosity is characterized by pores having a size of up to 5 nm.

28. The method of claim 24 , wherein said surface porosity is characterized by pores having a size of up to 1 nm.

Assignees

• Ut Battelle Llc

Inventors

• Sharma Jaswinder K

Classifications

• C08K2201/011

  Nanostructured additives · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C08K9/08

  Ingredients agglomerated by treatment with a binding agent · CPC title

• C08L83/04

  Polysiloxanes · CPC title

• C08L2207/53

  Core-shell polymer · CPC title