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. An article comprising:
at least two surfaces, and
an insulating material between at least two surfaces consisting essentially of
greater than or equal to about 40% wt aerogel particles and less than or equal to about 60% wt polytetrafluoroethylene (PTFE), at least a portion of which is fibrillated to form PTFE fibrils having a diameter of about 0.02 μm to about 0.1 μm,
the insulating material having 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 insulating structure of claim 1 wherein the insulating material is a putty.
3. The insulated article of claim 1 wherein at least one surface is rigid.
4. The insulated article of claim 1 wherein at least one surface is flexible.
5. The insulating article of claim 1 wherein the surfaces are non-porous.
6. The insulated articles of claim 1 wherein the surfaces are two walls of a double-walled pipe.
7. The insulated article of claim 1 wherein the surfaces are two walls of a double-walled container.
8. The article of claim 1 , wherein the article is under vacuum pressure between 0.001 Pa and 100 000 Pa.
9. The article of claim 1 wherein the material further comprise an opacifier.
10. The article of claim 1 wherein the material further comprises a dye.
11. The article of claim 1 wherein the material further comprises carbon black.
12. The article of claim 1 wherein the material further comprises titanium dioxide.
13. The article of claim 1 wherein the material further comprises silicon carbide.