# US 12,759,277 B2 · Hydrophobic silica wet gel and aerogel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,277 B2 - Document ID: US12759277B2 - Status: Granted - Kind: B2 - Application number: 18/637,818 - Filed: 2024-04-17 - Published: 2025-10-23 - Granted: 2026-10-13 - Earliest claimed: 2024-04-17 - Assignees: Cardinal CG Company - Applicants: Cardinal CG Company - Inventors: Reaz Ahmed Chowdhury; Kari B. Myli - Web page: https://patentgrep.com/patent/US12759277B2 ## CPC - B32B 38/0032: {increasing porosity (B32B38/04 takes precedence)} - B32B 5/18: characterised by features of a layer {of} foamed material - B32B 17/066: {of foam} - B32B 38/164: {Drying} - B32B 2038/0084: {Foaming} - B32B 2250/02: 2 layers - B32B 2266/057: Silicon-containing material, e.g. glass - B32B 2266/126: Aerogel, i.e. a supercritically dried gel - B32B 2305/022: Foam - B32B 2307/412: Transparent - B32B 2307/72: Density - B32B 2307/73: Hydrophobic - B32B 2307/7376: Thickness - B32B 2309/04: Time - B32B 2315/08: Glass - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM ## 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. ## Claims ### Claim 1 A method of making a hydrophobic silica aerogel, comprising the steps of: preparing a first solution by mixing tetramethyl orthosilicate and a first solvent; preparing a second solution by mixing a second 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 ammonium hydroxide and a third solvent; preparing a fourth solution by mixing methyltrimethoxysilane and diluent; preparing a solvent exchange solution by mixing the third solution, the fourth solution and an additional solvent; subjecting the silica wet gel to the solvent exchange solution to form a hydrophobic silica wet gel; and drying the hydrophobic silica wet gel to form hydrophobic silica aerogel; wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 2.3% and less than or equal to 5.5% and the methyltrimethoxysilane has a total weight percent of greater than or equal to 0.5% and less than or equal to 0.8%, wherein total weight percent represents a total weight percent of a component in the first, second, third and fourth solutions. ### Claim 2 (depends on 1) The method of claim 1 wherein: the total weight percent of the tetramethyl orthosilicate is greater than or equal to 2.3% and less than or equal to 5.5%; the total weight percent of the methyltrimethoxysilane is greater than or equal to 0.5% and less than or equal to 0.8%; the first solvent, the second solvent, the third solvent and the diluent comprise methanol and the methanol has a total weight percent of greater than or equal to 91.8% and less than or equal to 95.2%; the water has a total weight percent of greater than or equal to 1.9% and less than or equal to 2%; and the ammonium hydroxide has a total weight percent of greater than or equal to 0.013% and less than or equal to 0.015%. ### Claim 3 (depends on 1) The method of claim 1 wherein the first solution comprises tetramethyl orthosilicate at a weight percent of greater than or equal to 23.5% and less than or equal to 52% and methanol at a weight percent of greater than or equal to 48% and less than or equal to 76.5%, the second solution comprises water at a weight percent of greater than or equal to 99.6% and less than or equal to 99.7% and ammonium hydroxide at a weight percent of greater than or equal to 0.3% and less than or equal to 0.4%, the third solution comprises ammonium hydroxide at a weight percent of greater than or equal to 3.7% and less than or equal to 3.8% and methanol at a weight percent of greater than or equal to 96.2% and less than or equal to 96.3%, and the fourth solution comprises methyltrimethoxysilane at a weight percent of greater than or equal to 19.5% and less than or equal to 26.8% and methanol at a weight percent of greater than or equal to 73.2% and less than or equal to 80.5%. ### Claim 4 (depends on 1) The method of claim 1 wherein the hydrophobic silica aerogel has a density of between 120 mg/cc and 200 mg/cc, the total weight percent of the tetramethyl orthosilicate is greater than or equal to 2.8% and less than or equal to 5.5%, and the total weight percent of the methyltrimethoxysilane is greater than or equal to 0.5% and less than or equal to 0.8%. ### Claim 5 (depends on 4) The method of claim 4 wherein: the total weight percent of the tetramethyl orthosilicate is greater than or equal to 2.8% and less than or equal to 5.5%; the total weight percent of the methyltrimethoxysilane is greater than or equal to 0.5% and less than or equal to 0.8%; the first solvent, the second solvent, the third solvent and the diluent comprise methanol and the methanol has a total weight percent of greater than or equal to 91.8% and less than or equal to 94.7%; the water has a total weight percent of greater than or equal to 1.9% and less than or equal to 2%; and the ammonium hydroxide has a total weight percent of greater than or equal to 0.013% and less than or equal to 0.015%. ### Claim 6 (depends on 4) The method of claim 4 wherein the first solution comprises tetramethyl orthosilicate at a weight percent of greater than or equal to 28.4% and less than or equal to 52% and methanol at a weight percent of greater than or equal to 48% and less than or equal to 71.6%, the second solution comprises water at a weight percent of greater than or equal to 99.6% and less than or equal to 99.7% and ammonium hydroxide at a weight percent of greater than or equal to 0.3% and less than or equal to 0.4%, the third solution comprises ammonium hydroxide at a weight percent of greater than or equal to 3.7% and less than or equal to 3.8% and methanol at a weight percent of greater than or equal to 96.2% and less than or equal to 96.3%, and the fourth solution comprises methyltrimethoxysilane at a weight percent of greater than or equal to 19.5% and less than or equal to 26.8% and methanol at a weight percent of greater than or equal to 73.2% and less than or equal to 80.5%. ### Claim 7 (depends on 1) The method of claim 1 wherein the hydrophobic silica aerogel has a density of between 120 mg/cc and 150 mg/cc, the total weight percent of the tetramethyl orthosilicate is greater than or equal to 2.8% and less than or equal to 4.3%, and the total weight percent of the methyltrimethoxysilane is greater than or equal to 0.5% and less than or equal to 0.7%. ### Claim 8 (depends on 7) The method of claim 7 wherein: the total weight percent of the tetramethyl orthosilicate is greater than or equal to 2.8% and less than or equal to 4.3%; the total weight percent of the methyltrimethoxysilane is greater than or equal to 0.5% and less than or equal to 0.7%; the first solvent, the second solvent, the third solvent and the diluent comprise methanol and the methanol has a total weight percent of greater than or equal to 93.1% and less than or equal to 94.7%; the water has a total weight percent of greater than or equal to 1.9% and less than or equal to 2%; and the ammonium hydroxide has a total weight percent of greater than or equal to 0.013% and less than or equal to 0.015%. ### Claim 9 (depends on 7) The method of claim 7 wherein the first solution comprises tetramethyl orthosilicate at a weight percent of greater than or equal to 28.4% and less than or equal to 41.3% and methanol at a weight percent of greater than or equal to 58.7% and less than or equal to 71.6%, the second solution comprises water at a weight percent of greater than or equal to 99.6% and less than or equal to 99.7% and ammonium hydroxide at a weight percent of greater than or equal to 0.3% and less than or equal to 0.4%, the third solution comprises ammonium hydroxide at a weight percent of greater than or equal to 3.7% and less than or equal to 3.8% and methanol at a weight percent of greater than or equal to 96.2% and less than or equal to 96.3%, and the fourth solution comprises methyltrimethoxysilane at a weight percent of greater than or equal to 19.5% and less than or equal to 23.3% and methanol at a weight percent of greater than or equal to 76.7% and less than or equal to 80.5%. ### Claim 10 (depends on 1) The method of claim 1 further comprising a step of aging the hydrophobic silica wet gel for a time period of at least 7 days (168 hours). ### Claim 11 (depends on 1) The method of claim 1 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. ### Claim 12 (depends on 1) 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. ### Claim 13 (depends on 1) 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 visible transmission of at least 97.8% and a haze value of 3% or less. ### Claim 14 (depends on 1) The method of claim 1 wherein the method is devoid of using a surfactant. ### Claim 15 (depends on 10) The method of claim 10 wherein the time period for aging the hydrophobic silica wet gel is at least 10 days. ### Claim 16 (depends on 12) The method of claim 12 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a shrinkage value of 3% or less. ### Claim 17 (depends on 16) The method of claim 16 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a shrinkage value of 2% or less. ### Claim 18 (depends on 17) The method of claim 17 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a shrinkage value of 1.75% or less. ### Claim 19 (depends on 12) The method of claim 12 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a visible transmission of at least 98% and a haze value of 3% or less. ### Claim 20 (depends on 19) The method of claim 19 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a visible transmission of at least 98.6% and a haze value of 2.5% or less. ### Claim 21 (depends on 20) The method of claim 20 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a visible transmission of at least 99% and a haze value of 2% or less. ### Claim 22 (depends on 1) 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 water contact angle of at least 90°. ### Claim 23 (depends on 22) The method of claim 22 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a water contact angle of at least 100°. ### Claim 24 (depends on 23) The method of claim 23 wherein the hydrophobic silica aerogel formed by drying the hydrophobic silica wet gel has a water contact angle of at least 110°. ### Claim 25 (depends on 1) The method of claim 1 wherein the additional solvent comprises methanol.