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

Patent metadata

Field	Value
Publication number	US-11155690-B2
Application number	US-201916717553-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Apr 11, 2014
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

The invention relates to a process for preparing a gelled, dried composition forming a monolithic aerogel with a heat conductivity of less than or equal to 40 mW·m−1·K−1 and derived from a resin of polyhydroxybenzene(s) and formaldehyde(s), to this aerogel composition and to the use thereof. This process comprises:a) polymerization in an aqueous solvent of said polyhydroxybenzene(s) and formaldehyde(s) in the presence of an acidic or basic catalyst, to obtain a solution based on the resin,b) gelation of the solution obtained in a) to obtain a gel of the resin, andc) drying of the gel to obtain a dried gel.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 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 gelled, dried and non-pyrolyzed composition being based on a resin derived at least partly from polyhydroxybenzene(s) R and formaldehyde(s) F and being obtained by a process comprising:
a) polymerization in an aqueous solvent W of said polyhydroxybenzene(s) R and formaldehyde(s) F in the presence of an acidic or basic catalyst and of at least one water-soluble cationic polyelectrolyte P dissolved in the solvent, to obtain a solution based on said resin,
b) gelation of the solution obtained in a) to obtain a gel of said resin,
c) drying of the gel obtained in b) to obtain a dried gel, and
d) heat treatment under inert gas of the dried gel at temperatures of between 150° C. and 500° C. to obtain the gelled, dried and non-pyrolyzed composition forming the aerogel
wherein the gelled, dried and non-pyrolyzed composition;
comprises the at least one water-soluble cationic polyelectrolyte P which is used in the solution of step a) in a mass fraction of between 0.2% and 2%, and
has said heat conductivity which increases by less than 10% and less than 20%, respectively, after 1 hour and 2 hours of exposure to a humid atmosphere regulated at 20° C. and 65% relative humidity, said heat conductivity being measured with a Neotim conductimeter via the hot wire technique according to standard ASTM D5930-97.

2. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said heat conductivity is measured according to the RILEM recommendation AAC 11-3.

3. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said heat conductivity is less than or equal to 30 mW·m −1 ·K −1 , after the said 2 hours of exposure to said humid atmosphere.

4. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said heat conductivity is less than or equal to
26 mW·m −1 ·K −1 , after the said 2 hours of exposure to said humid atmosphere.

5. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein the gelled, dried and non-pyrolyzed composition has a mass proportion of water uptake of less than 3% and 5%, respectively, after 1 hour and 2 hours of exposure to said humid atmosphere.

6. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said aerogel has a core and a surface layer both comprising oxygenated groups.

7. The gelled, dried and non-pyrolyzed composition as claimed in claim 6 , wherein said aerogel has a polymeric structure essentially based on a repeating unit comprising an aromatic nucleus to which are bonded at least one alkyl group and several said oxygenated groups comprising at least one hydroxyl group and/or at least one formaldehyde group.

8. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein the gelled, dried and non-pyrolyzed composition comprises at least one filler that is capable of absorbing infrared radiation.

9. The gelled, dried and non-pyrolyzed composition as claimed in claim 8 , wherein said at least one filler is a carbon black.

10. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said aerogel emits a total concentration of volatile organic compounds (VOC), measured in an emission test chamber according to standard NF ISO 16006-6 of 2005 with specimens prepared according to standard NF EN ISO 16000-11 and conditioned according to standard NF EN ISO 16000-9, which:
after 3 days of exposure in said test chamber, is less than 100 μg·m −3 , and/or which
after 28 days of exposure in said test chamber, is less than 40 μg·m −3 .

11. The gelled, dried and non-pyrolyzed composition as claimed in claim 10 , wherein said aerogel emits a total concentration of volatile organic compounds (VOC), measured in an emission test chamber according to standard NF ISO 16006-6 of 2005 with specimens prepared according to standard NF EN ISO 16000-11 and conditioned according to standard NF EN ISO 16000-9, which:
after 3 days of exposure in said test chamber, is less than 40 μg·m −3 , and/or which
after 28 days of exposure in said test chamber, is less than 10 μg·m −3 .

12. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said aerogel emits a concentration of formaldehyde, measured in an emission test chamber according to standard NF ISO 16006-3 of 2002 with specimens prepared according to NF EN ISO 16000-11 and conditioned according to standard NF EN ISO 16000-9, which:
after 3 days of exposure in said test chamber, is less than 20 μg·m −3 , and/or which
after 28 days of exposure in said test chamber, is less than 20 μg·m −3 .

13. The gelled, dried and non-pyrolyzed composition as claimed in claim 12 , wherein said aerogel emits a concentration of formaldehyde, measured in an emission test chamber according to standard NF ISO 16006-3 of 2002 with specimens prepared according to NF EN ISO 16000-11 and conditioned according to standard NF EN ISO 16000-9, which:
after 3 days of exposure in said test chamber, is less than 5 μg·m −3 , and/or which
after 28 days of exposure in said test chamber, is less than 5 μg·m −3 .

14. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein the gelled, dried and non-pyrolyzed composition has a specific surface area of between 400 m 2 /g and 1200 m 2 /g and a specific gravity of between 0.04 and 0.2.

15. The gelled, dried and non-pyrolyzed composition as claimed in claim 1 , wherein said at least one cationic polyelectrolyte P is an organic polymer chosen from the group consisting of polymeric quaternary ammonium salts, poly(vinylpyridinium chloride), a cationic poly(ethyleneimine), a cationic poly(vinylpyridine), poly(allylamine hydrochloride), poly(trimethylammonium chloride ethylmethacrylate), poly(acrylamide-co-dimethylammonium chloride) and mixtures thereof.

16. The gelled, dried and non-pyrolyzed composition as claimed in claim 15 , wherein said at least one cationic polyelectrolyte P a polymeric salt comprising units derived from a quaternary ammonium chosen from poly(diallyldimethylammonium halides).

Assignees

• Hutchinson

Inventors

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

Classifications

• F16L59/028

  Compositions for or methods of fixing a thermally insulating material · CPC title

• C08J9/0061

  characterized by the use of several polymeric components · CPC title

• B01J13/0091

  Preparation of aerogels, e.g. xerogels · CPC title

• C08J3/075

  Macromolecular gels · CPC title

• C08J2201/0504

  the liquid phase being aqueous · CPC title