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 materiel comprising
greater than or equal to about 40% wt aerogel particles and
less than or equal to about 60% wt polytetrafluoroethylene (PTFE) particle having a particle size of from about 50 nm to about 600 μm as a binder,
wherein the material is a powder or a putty, and the material has a thermal conductivity of less than or equal to 25 milliwatts per meter Kelvin (mW/m K) at atmospheric conditions (298.15 K and 101.3 kPa).
2. The material of claim 1 wherein the 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).
3. The material 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).
4. The material of claim 1 wherein the aerogel has an average pore size less than or equal to about 100 nm.
5. The material of claim 1 wherein the aerogel is present in an amount of greater than or equal to about 60% wt.
6. The material of claim 1 wherein the aerogel is present in an amount of greater than or equal to about 80% wt.
7. The material of claim 1 wherein the aerogel is formed from an inorganic oxide.
8. The material of claim 1 where the aerogel is silica aerogel.
9. The material of claim 1 further comprising at least one additional component selected from opacifiers, dies, fibers and polymers.
10. The material of claim 9 wherein the opacifier is carbon black, titanium dioxide, iron oxides, silicon carbide, molybdenum silicide, manganese oxide or polydialkylsiloxanes, wherein the alkyl groups contain 1 to 4 carbon atoms.
11. The material of claim 1 wherein the material is formable or moldable.
12. The material of claim 1 wherein the material is between two walls of a double walled container.
13. The material of claim 1 wherein the material is formed as a tape.