Monolithic, super heat-insulating, organic aerogel composition preparation method, said composition, and the use thereof

Patent metadata

Field	Value
Publication number	US-10550238-B2
Application number	US-201415302431-A
Country	US
Kind code	B2
Filing date	Apr 11, 2014
Priority date	Apr 11, 2014
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

According to the invention, step a) is performed in the presence of a cationic polyelectrolyte dissolved in this solvent, and the process also comprises a step d) of heat treatment under inert gas of the dried gel obtained in step c) at temperatures of between 150° C. and 500° C. to obtain the non-pyrolyzed aerogel whose heat conductivity is substantially unchanged, even after exposure to a humid atmosphere.

First claim

The invention claimed is:

1. A process for preparing a gelled, dried and non-pyrolyzed composition forming an organic monolithic aerogel with a heat conductivity of less than or equal to 40 mW·m−1·K−1, the composition being at least partly derived from a resin obtained by polycondensation of at least one polyhydroxybenzene R and at least one formaldehyde F, the process comprising:
a) polymerizing the at least one polyhydroxyhenzene R and the at least one formaldehyde in an aqueous solvent W in the presence of an acidic or basic catalyst, to obtain a solution based on the resin;
b) gelling the solution to obtain a gel of the resin; and
c) drying the gel to obtain a dried gel,
wherein:
the polymerizing a) is performed in the presence of at least one water-soluble cationic polyelectrolyte P dissolved in aqueous solvent W; and
the process further comprises a step d) of heat treating the dried gel under an inert gas at temperatures of between 150° C. and 500° C. to obtain the gelled, dried and non-pyrolyzed composition.

2. The process of claim 1 , wherein the dried gel has a core and a surface layer which both comprise oxygenated groups, which are only partially carbonized in the heat treating, such that the gelled, dried and non-pyrolyzed composition comprises several said oxygenated groups which are intact in the core and in the surface layer.

3. The process of claim 2 , wherein the gelled, dried and non-pyrolyzed composition comprises hydroxyl groups, formaldehyde groups, or both, as the oxygenated groups.

4. The process of claim 1 , wherein the heating treating d) comprises at least one temperature increase followed by at least one heat stabilization stage, and ends with gradual cooling to a temperature of between 15 and 30° C.

5. The process of claim 4 , wherein the heat treating d) comprises:
a first temperature increase at a rate of between 1 and 5° C./minute up to an intermediate temperature of between 100 and 200° C., followed by a first stabilization stage at the intermediate temperature lasting between 5 and 30 minutes;
a second temperature increase at a rate of between 2 and 10° C./minute up to a final temperature of between 240 and 460° C., followed by a second stabilization stage at the final temperature lasting between 1 hour and 3 hours; and then
said gradual cooling for a time of at least 45 minutes to a temperature of between 20 and 25° C.

6. The process of claim 1 , wherein the at least one water-soluble cationic polyelectrolyte P used during the polymerizing a) is present in the gelled, dried and non-pyrolyzed composition at a mass fraction of between 0.2% and 2% relative to a total mass of the composition.

7. The process of claim 1 , wherein the at least one water-soluble cationic polyelectrolyte P is an organic polymer selected from the group consisting of an organic quaternary ammonium salt, a poly(vinylpyridine chloride), a poly(ethyleneimine), a poly(vinylpyridine), a poly(allylamine hydrochloride), a poly(trimethylammonium chloride ethylmethacrylate), a poly(acrylamide-co-dimethylammonium chloride) and mixtures thereof.

8. The process of claim 1 , wherein the polymerizing a) occurs at a temperature of between 15 and 30° C., by dissolving the at least one polyhydroxybenzene R and the at least one cationic polyelectrolyte P in the aqueous solvent W, followed by adding to a solution obtained the at least one formaldehyde F and the acidic or basic catalyst.

9. The process of claim 1 , wherein, before the gelling b), at least one filler that is capable of absorbing infrared radiation is added to the solution.

10. The process of claim 1 , wherein the drying c) is performed by oven drying, the drying c) being performed without solvent exchange and without drying with a supercritical fluid.

Assignees

• Hutchinson

Inventors

• Dufour Bruno
• Swoboda Benjamin
• Huillet Cedric
• Fannechere Florian
• Poupa Nadine

Classifications

• C08J2205/028

  Xerogel, i.e. an air dried gel · CPC title

• C08J2205/02

  the finished foam itself being a gel or a gel being temporarily formed when processing the foamable composition · CPC title

• C08J2201/0504

  the liquid phase being aqueous · CPC title

• C08J2361/04

  Condensation polymers of aldehydes or ketones with phenols only · CPC title

• C08J2479/02

  Polyamines · CPC title