Molding based on a monolithic organic aerogel
A molding based on a monolithic organic aerogel has a density in the range from 60 to 300 kg/m 3 and a thermal conductivity in the range from 12 to 17.8 mW/m*K. The molding based on a monolithic organic aerogel has more than 30 vol.-% of pores with a diameter of less than 150 nm, and more than 20 vol.-% of pores with a diameter of less than 27 nm, based on the total pore volume. A process can be used to prepare the molding by compression.
1. A molding based on a monolithic organic aerogel, having a density in the range from 60 to 300 kg/m 3 , and a thermal conductivity in the range from 12 to 17.8 mW/m*K, measured according to DIN EN 12667:2001-05 at 10° C. and 101,325 Pa, and
wherein the molding comprises 40 to 80 vol.-% of pores with a diameter of less than 150 nm, 21 to 75 vol.-% of pores with a diameter of less than 27 nm, based on a total pore volume; wherein the fraction of pores with diameter of 150 nm and higher is 20-60 vol %;
wherein the molding is in the form of a sheet with a thickness in the range from 100 μm to 10 mm; and
wherein the monolithic organic aerogel is based on polyurethane, polyurea or polyisocyanurate or mixtures thereof.
2. The molding as defined in claim 1 , which has a compression strength in the range from 600-700 kPa, determined according to DIN EN ISO 844:2014-11.
3. The molding as defined in claim 1 , which has a flexural strength in the range from 1000-5000 KPa, determined according to DIN EN 12089:2013-06.
4. The molding as defined in claim 1 , wherein the monolithic organic aerogel is a monolithic aerogel based on the polyurethane (PU) and/or the polyurea (PUR) with less than 80% of the polyisocyanurate (PIR) structures.
5. The molding as defined in claim 1 , which has a density in the range from 140 to 240 kg/m 3 .
6. A process for preparing the molding as defined in claim 1 , the process comprising:
compressing a molding based on an organic aerogel with a density in the range from 50 to 140 kg/m 3 , and with a compression factor in the range from 5 to 70 vol.-%.
7. The process according to claim 6 , wherein the compression is performed in a hydraulic or pneumatic press.
8. The process as defined in claim 6 , wherein the molding based on an organic aerogel is compressed in the form of a sheet unidirectional in the direction of the thickness of the sheet.
9. The process as defined in claim 6 , wherein the compression is performed in a hydraulic or pneumatic press at a temperature of the molding between 10° and 80° C.
10. A process for preparing the molding as defined in claim 1 , the process comprising:
a) reacting a mixture (A) comprising at least one polyfunctional isocyanate (a1), at least one aromatic amine (a2), and at least a catalyst (a3), in the presence of a solvent (B), to form a gel,
b) drying the gel obtained in a) under supercritical conditions, to obtain a dried gel,
c) optionally, cutting the dried gel into sheets with a thickness in the range from 0.1 to 10 mm, and
d) compressing the dried gel to a density in the range from 100 to 300 kg/m 3 .
11. A thermal insulation material, comprising the molding according to claim 1 as an aerogel layer A), and at least one cover layer C) with a thickness in the range from 10 μm to 1 mm.
12. A process for preparing a thermal insulation material according to claim 11 , the process comprising:
a) reacting a mixture (A) comprising at least one polyfunctional isocyanate (a1), at least one aromatic amine (a2), and at least a catalyst (a3), in the presence of a solvent (B), to form a gel,
b) drying the gel obtained in a) under supercritical conditions, to form a monolithic aerogel,
c) optionally, cutting the monolithic aerogel into sheets with a thickness in the range from 0.1 to 10 mm,
compressing the monolithic aerogel from b) to a density in the range from 100 to 300 kg/m 3 , to obtain the aerogel layer A), and
e) applying at least one cover layer C), optionally, by an adhesive layer B), to the aerogel layer A) obtained in d).
13. The thermal insulation material as defined in claim 11 , wherein the thermal insulation material is a thermal insulation material in building and/or construction, in a refrigeration appliance, in an electronic device, in aerospace, and/or in a battery.