Aerogel/PTFE composite insulating material
View Patent ↗A material comprising aerogel particles and a polytetrafluoroethylene (PTFE) binder is formed having a thermal conductivity of less than or equal to 25 mW/m K at atmospheric conditions. The material is moldable or formable, having little or no shedding of filler particles, and may be formed into structures such as tapes or composites, for example, by bonding the material between two outer layers. Advantageously, composites may be flexed, stretched, or bent without significant dusting or loss of insulating properties.
1. A structure comprising:
two layers and
a material between the two layers comprising greater than or equal to about 40% wt aerogel particles and less than or equal to about 60% wt polytetrafluoroethylene (PTFE) particles having a particle size of from about 50 nm to about 600 μm, wherein the material is a powder or a putty and the material has a thermal conductivity of less than or equal to 25 mW/m K at atmospheric conditions (298.15 K and 101.3 kPa).
2. The structure of claim 1 wherein at least one of the layers is impermeable to liquids.
3. The structure of claim 1 wherein at least one of the layers is impermeable to gases.
4. The structure of claim 1 , wherein at least one of layers is selected from metal foils and metallized polymer films.
5. The structure of claim 1 , wherein at least one of the layers is aluminum or copper.
6. The structure of claim 1 , wherein the layers are comprised of expanded polytetrafluoroethylene (ePTFE).
7. The structure of claim 1 wherein at least one of the layers is permeable to gases.
8. The structure of claim 1 , wherein at least one of the layers is permeable to water vapor.
9. The structure of claim 7 , wherein at least one of the layers comprises expanded polytetrafluorethylene (ePTFE).
10. The structure of claim 1 , wherein at least one of the layers comprises continuous polymer film.
11. The structure of claim 7 , wherein at least one of the layers comprises polyurethane.
12. The structure of claim 1 , wherein at least one of the layers is elastomeric.
13. The structure of claim 12 , wherein at least one of the layers is a thermoplastic elastomer.
14. The structure of claim 13 , wherein at least one of the layers comprises polyurethane, polyesters, polyamides and copolymers thereof.
15. The structure of claim 1 wherein the insulating material has a thermal conductivity of less than or equal to about 20 mW/m K at atmospheric conditions (298.15 K and 101.3 kPa).
16. The structure of claim 1 wherein the material has a thermal conductivity of less than or equal to about 17 mW/m K at atmospheric conditions (298.15 K and 101.3 kPa).
17. The structure of claim 1 wherein the aerogel is formed from an inorganic oxide.
18. The structure of claim 1 wherein the aerogel is silica aerogel.
19. The structure of claim 1 wherein the material further comprises at least one additional component.
20. The structure of claim 1 wherein the material further comprises an opacifier.
21. The structure of claim 1 wherein the material is bonded between two layers with a non-adhesive bonding.
22. The structure of claim 1 wherein the material is bonded between two layers with an adhesive.
23. The structure of claim 1 wherein the structure is formed as a tape.
24. The structure of claim 1 wherein the structure may be flexed or wrapped without a substantial change in thermal conductivity.
25. The structure of claim 1 wherein the structure is wrapped around a pipe to form an insulated pipe.
26. The structure of claim 1 wherein the structure is an insert for use in apparel.
27. The structure of claim 1 wherein the structure is an insert for use in footwear.
28. The structure of claim 1 wherein the structure is an insert for use in gloves.
29. The structure of claim 1 , wherein the structure has a thickness of greater than or equal to about 0.5 mm.