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1. (WO2019042968) A COMPOSITE AEROGEL AND PREPARATION METHOD AND APPLICATION THEREOF
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Claims

1. A preparation method of a composite aerogel, comprising the following steps:

a) reacting an amino silane coupling agent, a silicon compound selected from the group consisting of sodium silicate, tetraalkyl orthosilicate, monomeric alkylalkoxysilane, bis-trialkoxyalkyl silane, bis-trialkoxyaryl silane, and polyhedral silsesquioxane with water to form a compound containing silicon skeletons;

b) reacting the compound containing silicon skeletons, an isocyanate having a functionality of 2 to 4 selected from the group consisting of aliphatic iso- cyanates, cycloaliphatic isocyanates and aromatic isocyanates and mixtures thereof, a compound containing an isocyanate reactive group selected from the group consisting of polyester polyols, polyacrylate polyols, polyurethane polyols, polycarbonate polyols, polyether polyols, polyester polyacrylate polyols, polyurethane polyacrylate polyols, polyurethane polyester polyols, polyurethane polyether polyols, polycarbonate polyether polyols, polyurethane polycarbonate polyols, polyester polycarbonate polyols, mono-, di-, trifunctional amines, mono-, di-, trifunctional hydroxylamines, aliphatic and alicyclic primary and/or secondary monoamines, amino alcohols, diamines, triamines, piperazines, adipic dihydrazide, hydrazine and hydrazine hydrate and mixtures thereof and an organic solvent selected from the group consisting of acetone, methanol, ethanol, isopropanol and tetrahydrofuran and mixtures thereof to form a wet gel; and

c) drying the wet gel to obtain the composite aerogel

wherein the reaction temperatures of step a and step b are no more than 0°C, preferably -30°C-0°C, independently of each other and

wherein the mass ratio of the silicon compound and the amino silane coupling agent is 2: 1-5: 1.

2. The preparation method according to claim 1, characterized in that, the drying in step c) is C02 supercritical drying.

3. The preparation method according to claim 1, characterized in that, the ratio of the mass of the amino silane coupling agent and the silicon compound to the mass of water is 3:1-6: 1.

4. The preparation method according to claim 1, characterized in that, the molar ratio of the isocyanate groups of the isocyanate and the isocyanate reactive groups of the compound containing an isocyanate reactive group is 120-600: 1, preferably 120: 1.

5. The preparation method according to claim 1, characterized in that, the composite aerogel has a thermal conductivity of 0.008 W/m»K -0.040 W/m»K, preferably of 0.015 W/m«K -0.025 W/m«K, most preferably of 0.019W/m«K-0.023W/m«K, measured under one atmospheric pressure and at ambient temperature.

6. The preparation method according to claim 1, characterized in that, the silicon compound is tetraalkyl orthosilicate, preferably tetraethyl orthosilicate and/or tetramethyl orthosilicate.

7. The preparation method according to claim 1, characterized in that, the amino silane coupling agent is 3-aminopropyltriethoxysilane.

8. The preparation method according to claim 1, characterized in that, the mass ratio of the silicon compound and the amino silane coupling agent is 2: 1-3: 1.

9. The preparation method according to claim 1, characterized in that, the content of silicon groups present in the composite aerogel is no more than 30 wt , based on that the weight of the composite aerogel is 100 wt

10. Use of the composite aerogel prepared according to any one of claims 1-9 for preparing a thermal insulation material.

11. A thermal insulation material comprising the composite aerogel prepared according to any one of claims 1-9.