Hydrophobic silica wet gel and aerogel

Patent metadata

Field	Value
Publication number	US-2024367983-A1
Application number	US-202418636411-A
Country	US
Kind code	A1
Filing date	Apr 16, 2024
Priority date	Apr 20, 2023
Publication date	Nov 7, 2024
Grant date	—

Abstract

The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.

First claim

What is claimed is:

1 . A method of making a hydrophobic silica aerogel having a density of between 100 mg/cc and 200 mg/cc, comprising the steps of:
preparing a first solution by mixing methyl silicate 51 and solvent; preparing a second solution by mixing solvent, ammonium hydroxide and water; mixing the first solution and the second solution together to form a mixed solution; allowing components in the mixed solution to react to form silica wet gel; preparing a third solution by mixing methyltrimethoxysilane and diluent, and wherein the third solution comprises the methyltrimethoxysilane in a controlled amount selected to provide a molar ratio of methyl silicate 51:methyltrimethoxysilane of greater than or equal to 0.95:1 and less than or equal to 2.55:1; adding the third solution to the silica wet gel; allowing the third solution to react with the silica wet gel to form hydrophobic silica wet gel; and drying the hydrophobic silica wet gel to form hydrophobic silica aerogel.

2 . The method of claim 1 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 0.98:1 and less than or equal to 1.43:1.

3 . The method of claim 1 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.3:1 and less than or equal to 1.7:1.

4 . The method of claim 1 wherein the density of the hydrophobic silica aerogel is between 120 mg/cc and 200 mg/cc and the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.2:1 and less than or equal to 2.55:1.

5 . The method of claim 4 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.25:1 and less than or equal to 1.43:1.

6 . The method of claim 4 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.60:1 and less than or equal to 1.71:1.

7 . The method of claim 1 wherein the density of the hydrophobic silica aerogel is between 120 mg/cc and 150 mg/cc and the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.2:1 and less than or equal to 2:1.

8 . The method of claim 7 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.25:1 and less than or equal to 1.29:1.

9 . The method of claim 7 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.60:1 and less than or equal to 1.66:1.

10 . The method of claim 1 wherein the solvent is methanol.

11 . The method of claim 1 wherein the diluent is methanol.

12 . The method of claim 1 further comprising a step of aging the silica wet gel or the hydrophobic silica wet gel for a time period of at least 7 days (168 hours) before the step of adding the third solution to the silica wet gel.

13 . The method of claim 1 further comprising a step of subjecting the hydrophobic silica wet gel to solvent extraction with methanol for an extraction time period of less than 24 hours.

14 . The method of claim 1 wherein the step of drying the hydrophobic silica wet gel to form hydrophobic silica aerogel comprises subjecting the hydrophobic silica wet gel to drying to form the hydrophobic silica aerogel with a shrinkage value of 4% or less.

15 . The method of claim 1 wherein the step of drying the hydrophobic silica wet gel to form hydrophobic silica aerogel comprises subjecting the hydrophobic silica wet gel to drying to form the hydrophobic silica aerogel to have a visible transmission of at least 97.8% and a haze value of 3% or less.

16 . The method of claim 1 wherein the method is devoid of using a surfactant.

17 . An article comprising a glass substrate and a hydrophobic silica aerogel sheet, the hydrophobic silica aerogel sheet being adhered to the glass substrate, the hydrophobic silica aerogel sheet having a density of between 100 mg/cc and 200 mg/cc and being synthesized from methyl silicate 51 and methyltrimethoxysilane in a controlled amount selected to provide a molar ratio of methyl silicate 51:methyltrimethoxysilane of greater than or equal to 0.95:1 and less than or equal to 2.55:1.

18 . The article of claim 17 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 0.98:1 and less than or equal to 1.43:1.

19 . The article of claim 17 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.3:1 and less than or equal to 1.71:1.

20 . The article of claim 17 wherein the density of the hydrophobic silica aerogel sheet is between 120 mg/cc and 200 mg/cc and the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.2:1 and less than or equal to 2.55:1.

21 . The article of claim 20 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.25:1 and less than or equal to 1.43:1.

22 . The article of claim 20 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.60:1 and less than or equal to 1.71:1.

23 . The article of claim 17 wherein the density of the hydrophobic silica aerogel sheet is between 120 mg/cc and 150 mg/cc and the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.2:1 and less than or equal to 2:1.

24 . The article of claim 23 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.25:1 and less than or equal to 1.29:1.

25 . The article of claim 23 wherein the molar ratio of methyl silicate 51:methyltrimethoxysilane is greater than or equal to 1.60:1 and less than or equal to 1.66:1.

26 . The article of claim 17 wherein the hydrophobic silica aerogel sheet has a thickness of between 2 mm and 5 mm.

27 . The article of claim 17 wherein the hydrophobic silica aerogel sheet has a visible transmission of at least 97.8% and a haze value of 3% or less.

28 . The article of claim 17 wherein the hydrophobic silica aerogel sheet has a haze value of 4% or less.

29 . The article of claim 17 wherein the hydrophobic silica aerogel sheet has a water contact angle of at least 90°.

Assignees

• Cardinal Cg Co

Inventors

• Chowdhury Reaz Ahmed
• Myli Kari B

Classifications

• B32B17/1055

  characterized by the resin layer, i.e. interlayer · CPC title

• B32B17/10036

  comprising two outer glass sheets · CPC title

• C01B33/1585 Primary

  Dehydration into aerogels · CPC title

• C01B33/155

  Preparation of hydroorganogels or organogels · CPC title

• B32B2307/414

  Translucent · CPC title