DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first
inventor to file provisions of the AIA .
Response to Amendment
The amendment filed on 07/16/2026 has been entered. Claims 1, 3-6, 8-16, 18, and 21-25 are pending in the application.
Applicant’s amendments to the claims have not introduced new matter and are supported in the specification in at least Pg. 2, lines 30-34 of the instant specification.
Response to Arguments
Applicant's arguments filed 07/16/2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 12-13 that Gan discloses colloidal silica while the claims required aqueous sodium silicate. Applicant argues a skilled artisan would have no apparent reason to switch from colloidal silica to aqueous sodium silicate.
However, the claims require “the aqueous silica precursor is selected from sodium silicate solutions, colloidal silica solutions, silica solutions extracted from a silica-rich source, waste from silica-based insulation material, glass, and mixtures thereof,” to which Gan teaches colloidal silica (Pg. 3, par. 1-3; Pg. 3-4, Examples 1-3).
In claim 24, where Applicant has amended the claim to focus solely on sodium silicate, a new grounds of rejection has been applied over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Evans et al. (US20160096949A1).
Applicant argues on Pg. 12 the reaction kinetics of Gan are extensive. Applicant argues the instant invention provides a quick and straightforward gelling over 10 min.
However, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., gelling time) are not recited in the rejected claims. Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
Applicant argues on Pg. 14 the solution would not gel properly because a skilled artisan would find no reason to change the pH range of 0-5 to the range of 4-6 taught by Gan.
However, Gan teaches the reaction is performed in a sealable container and describes the mixing of methyltrialkoxysilane, lower alcohol, water and silica sol in a closed container, adjusting the pH value to between 4-6 (Abstract; Pg. 3-4, Example 1). A pH of 4-6 overlaps the claimed range of 0-5. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Gan (pH 4-6) overlaps with the claimed range (pH between 0 and 5). Therefore, the range in Gan renders obvious the claimed range.
Applicant argues on Pg. 14-15 that the order of addition is a distinct feature of the claims and that an inversion of the steps is completely different chemistry. Applicant argues the claimed steps provide unexpected reaction kinetic improvements. Applicant cites examples 1 of the instant invention which describes a reaction occurring in 1 hour and compares this to Examples 1 to 3 of Gan that describe reactions occurring in 2 hours, 6 hours, and 1 hour + 20 hours.
However, this is not persuasive for at least the following reasons. First, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., gelling time) are not recited in the rejected claims. Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). The claims do not discuss the gelling time, aging time, drying time, or any other duration and accordingly the Examination of this property was not read into the instant claims.
Secondly, Example 1 of the instant invention does not disclose ripening, washing, or drying times and instead states “Following ripening and washing, the silica hydrogel is dried.” Accordingly, comparing the compounded time of Gan with only the stirring and gelling time of the instant invention is not a rigorous comparison. Furthermore, the instant application does not appear to supply any results that show unexpected or improved results from following the inventive example, as only a single inventive example is provided. The instant application does not appear to present any control experiments or other comparisons that support the claimed unexpected results.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C.
102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the
statutory basis for the rejection will not be considered a new ground of rejection if the prior art
relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness
rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the
claimed invention is not identically disclosed as set forth in section 102, if the
differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C.
103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or
nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 4, 8, 14-15, 21, 23, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026).
Regarding claim 1, Gan teaches a method of preparing a hydrophobic silica aerogel by first mixing a methyltrialkoxysilane, a lower alcohol, water and a silica sol in a closed container and adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution for gelation to provide an alcohol-wet gel that is then dried after washing to obtain the hydrophobic silica aerogel (Abstract; Claim 1; [0023]-[0028]). Gan teaches the silica sol is colloidal silica prepared with neutral or alkaline water solution (Pg. 3, par. 1-3; Pg. 3-4, Examples 1-3). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Gan (pH 4-6) overlaps with the claimed range (pH between 0 and 5). Therefore, the range in Gan renders obvious the claimed range.
Gan teaches the reaction is performed in a sealable container and describes the mixing of methyltrialkoxysilane, lower alcohol, water and silica sol in a closed container, adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution initiates gelation that provides an alcohol-wet gel occurring within the same container (Abstract; Pg. 3-4, Example 1). Accordingly, Gan sufficiently describes the reaction as occurring in a single, sealable container which meets the limitation “wherein steps i), ii) and iii) occur in the same reactor.”
Gan further teaches the organosilane is selected from methyltrialkoxysilanes with the general formula CH3-Si(OR)3, where R is methyl or ethyl, while teaching examples using methyltrimethoxysilane (Pg. 3, par. 3; Pg. 3-4, Examples 1-3).
Gan differs from the instant claim in that Gan adds silica sol, ethanol, and deionized water to the methyltrialkoxysilanes prior to pH adjustment to a pH between 4-6 (See Pg. 3, Examples 1-3), while the instant invention requires adding the organosilane to the mixture of aqueous silica precursor and alcohol, where the mixture of aqueous silica precursor and alcohol has had its pH adjusted to between 0 to 5.
However, the selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. See MPEP 2144.04.IV.C. Applicant has not provided data dismissing the Examiner’s conclusion of a distinguishing technical effect regarding the criticality of the order of addition. Given that Gan teaches the technical solution of providing the organosilane with the silica precursor during gelation according to claim 1, rather than performing hydrophobization after gelation, the process of Gan is considered relevant to the instantly claimed method.
Further, Gan teaches the advantageous effect of the process includes “In the initial stage of the reaction, a silylating agent (methyltrialkoxysilane) is added to the reactants for preparing the wet gel, so that the silylation reaction on the surface of the gel is in the gel of the sol. It can be carried out during the silylation process, which ensures the complete silylation reaction on the surface of the gel, improves the work efficiency, reduces the process flow, and realizes the preparation method of one-step synthesis of hydrophobic SiO2 airgel” (Pg. 3, par. 4).
The instant invention asserts hydrophobization throughout the gel is a substantially distinguishing technical effect (See Pg. 12 of the Remarks filed 09/10/2025) and that condensation of the silica precursor and organosilane during gelling achieve the homogenous hydrophobized gel matrix of the instant invention (see Pg. 17 of the Remarks filed 02/17/2026). Accordingly, a skilled artisan seeking to achieve the technical effect of obtaining complete silylation of the gel surface with the advantageous effects of improving the work efficiency and reducing the process flow would be motivated by the process of Gan despite the noted difference is the order of performing process steps.
Regarding claim 4, Gan teaches the method of claim 1 and Gan further teaches the alcohols is a lower alcohol being a C1-C3 monohydric, including ethanol (Claim 1; [0012]; [0024]).
Regarding claim 8, Gan teaches the method of claim 1 and Gan further teaches the organosilane is selected from methyltrialkoxysilanes with the general formula CH3-Si(OR)3, where R is methyl or ethyl, while teaching examples using methyltrimethoxysilane (Pg. 3, par. 3; Pg. 3-4, Examples 1-3).
Regarding claim 14, Gan teaches the method of claim 1 and Gan further teaches the hydrophobic silica aerogel can be combined with fibrous materials to form composites ([0004]).
Regarding claim 15, Gan teaches the method of claim 1 and Gan further teaches the drying can be carried out under normal pressure without vacuum ([0012]; [0014]).
Regarding claim 21, Gan teaches the method of claim 1, please see the rejection of claim 1 for a detailed mapping of the steps i)-iv).
As noted above, Gan differs from the instant claim in that Gan adds silica sol, ethanol, and deionized water to the methyltrialkoxysilane organosilane prior to pH adjustment to a pH between 4-6 (See Pg. 3, Examples 1-3), while the instant invention requires adding the organosilane to the mixture of aqueous silica precursor and alcohol, where the mixture of aqueous silica precursor and alcohol has had its pH adjusted to between 0 to 5.
However, the selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. See MPEP 2144.04.IV.C. Applicant has not provided data dismissing the Examiner’s conclusion of a distinguishing technical effect regarding the criticality of the order of addition. Examiner has responded to arguments regarding Applicant’s remarks stating the distinguishing characteristic would inherently flow from the teaching of the specification as filed. Given that Gan teaches the technical solution of providing the organosilane with the silica precursor during gelation according to claim 1, rather than performing hydrophobization after gelation, the process of Gan is considered relevant to the instantly claimed method.
Further, Gan teaches the advantageous effect of the process includes “In the initial stage of the reaction, a silylating agent (methyltrialkoxysilane) is added to the reactants for preparing the wet gel, so that the silylation reaction on the surface of the gel is in the gel of the sol. It can be carried out during the silylation process, which ensures the complete silylation reaction on the surface of the gel, improves the work efficiency, reduces the process flow, and realizes the preparation method of one-step synthesis of hydrophobic SiO2 airgel” (Pg. 3, par. 4).
The instant invention asserts hydrophobization throughout the gel is a substantially distinguishing technical effect (See Pg. 12 of the Remarks filed 09/10/2025) and that condensation of the silica precursor and organosilane during gelling achieve the homogenous hydrophobized gel matrix of the instant invention (see Pg. 17 of the Remarks filed 02/17/2026). Accordingly, a skilled artisan seeking to achieve the technical effect of obtaining complete silylation of the gel surface with the advantageous effects of improving the work efficiency and reducing the process flow would be motivated by the process of Gan despite the noted difference is the order of performing process steps.
Regarding claim 23, Gan teaches the method of claim 1, please see the rejection of claim 1 for a detailed mapping of the steps i)-iv).
As noted above, Gan differs from the instant claim in that Gan adds silica sol, ethanol, and deionized water to the methyltrialkoxysilane organosilane prior to pH adjustment to a pH between 4-6 (See Pg. 3, Examples 1-3), while the instant invention requires adding the organosilane to the mixture of aqueous silica precursor and alcohol, where the mixture of aqueous silica precursor and alcohol has had its pH adjusted to between 0 to 5.
However, the selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. See MPEP 2144.04.IV.C. Applicant has not provided data dismissing the Examiner’s conclusion of a distinguishing technical effect regarding the criticality of the order of addition. Examiner has responded to arguments regarding Applicant’s remarks stating the distinguishing characteristic would inherently flow from the teaching of the specification as filed. Given that Gan teaches the technical solution of providing the organosilane with the silica precursor during gelation according to claim 1, rather than performing hydrophobization after gelation, the process of Gan is considered relevant to the instantly claimed method.
Further, Gan teaches the advantageous effect of the process includes “In the initial stage of the reaction, a silylating agent (methyltrialkoxysilane) is added to the reactants for preparing the wet gel, so that the silylation reaction on the surface of the gel is in the gel of the sol. It can be carried out during the silylation process, which ensures the complete silylation reaction on the surface of the gel, improves the work efficiency, reduces the process flow, and realizes the preparation method of one-step synthesis of hydrophobic SiO2 airgel” (Pg. 3, par. 4).
The instant invention asserts hydrophobization throughout the gel is a substantially distinguishing technical effect (See Pg. 12 of the Remarks filed 09/10/2025) and that condensation of the silica precursor and organosilane during gelling achieve the homogenous hydrophobized gel matrix of the instant invention (see Pg. 17 of the Remarks filed 02/17/2026). Accordingly, a skilled artisan seeking to achieve the technical effect of obtaining complete silylation of the gel surface with the advantageous effects of improving the work efficiency and reducing the process flow would be motivated by the process of Gan despite the noted difference is the order of performing process steps.
Regarding claim 25, Gan teaches a method of preparing a hydrophobic silica aerogel by first mixing a methyltrialkoxysilane, a lower alcohol, water and a silica sol in a closed container and adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution for gelation to provide an alcohol-wet gel that is then dried after washing to obtain the hydrophobic silica aerogel (Abstract; Claim 1; [0023]-[0028]). Gan teaches the silica sol is colloidal silica prepared with neutral or alkaline water solution (Pg. 3, par. 1-3; Pg. 3-4, Examples 1-3). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Gan (pH 4-6) overlaps with the claimed range (pH between 0 and 5). Therefore, the range in Gan renders obvious the claimed range.
Gan teaches the reaction is performed in a sealable container and describes the mixing of methyltrialkoxysilane, lower alcohol, water and silica sol in a closed container, adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution initiate gelation that provides an alcohol-wet gel occurring within the same container (Abstract; Pg. 3-4, Example 1). Accordingly, Gan sufficiently describes the reaction as occurring in a single, sealable container which meets the limitation “wherein steps i), ii) and iii) occur in the same reactor.”
Gan teaches the silica sol is colloidal silica prepared with neutral or alkaline water solution (Pg. 3, par. 1-3; Pg. 3-4, Examples 1-3).
Gan further teaches the organosilane is selected from methyltrialkoxysilanes with the general formula CH3-Si(OR)3, where R is methyl or ethyl, while teaching examples using methyltrimethoxysilane (Pg. 3, par. 3; Pg. 3-4, Examples 1-3).
Gan differs from the instant claim in that Gan adds silica sol, ethanol, and deionized water to methyltrialkoxysilanes organosilane prior to pH adjustment to a pH between 4-6 (See Pg. 3, Examples 1-3), while the instant invention requires adding the organosilane to the mixture of aqueous silica precursor and alcohol, where the mixture of aqueous silica precursor and alcohol has had its pH adjusted to between 0 to 5.
However, the selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. See MPEP 2144.04.IV.C. Applicant has not provided data dismissing the Examiner’s conclusion of a distinguishing technical effect regarding the criticality of the order of addition. Given that Gan teaches the technical solution of providing the organosilane with the silica precursor during gelation according to claim 1, rather than performing hydrophobization after gelation, the process of Gan is considered relevant to the instantly claimed method.
Further, Gan teaches the advantageous effect of the process includes “In the initial stage of the reaction, a silylating agent (methyltrialkoxysilane) is added to the reactants for preparing the wet gel, so that the silylation reaction on the surface of the gel is in the gel of the sol It can be carried out during the silylation process, which ensures the complete silylation reaction on the surface of the gel, improves the work efficiency, reduces the process flow, and realizes the preparation method of one-step synthesis of hydrophobic SiO2 airgel” (Pg. 3, par. 4).
The instant invention asserts hydrophobization throughout the gel is a substantially distinguishing technical effect (See Pg. 12 of the Remarks filed 09/10/2025) and that condensation of the silica precursor and organosilane during gelling achieve the homogenous hydrophobized gel matrix of the instant invention (see Pg. 17 of the Remarks filed 02/17/2026). Accordingly, a skilled artisan seeking to achieve the technical effect of obtaining complete silylation of the gel surface with the advantageous effects of improving the work efficiency and reducing the process flow would be motivated by the process of Gan despite the noted difference is the order of performing process steps.
Claim 3 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Yoo (WO2009038393A2).
Regarding claim 3, Gan teaches the method of claim 1.
The claim further requires “the aqueous precursor solution contains between 4 and 8 wt.% SiO2” to which Gan teaches a silica range from 20-40 wt.% ([0015]).
Yoo teaches a process where sodium silicate solutions are prepared as a precursor for aerogels, where the silica precursors have a concentration of silica by weight of 5-15% (Pg. 6, par. 5). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Yoo (silica by weight of 5-15%) overlaps with the claimed range (aqueous precursor solution contains between 4 and 8 wt.% SiO2). Therefore, the range in Yoo renders obvious the claimed range.
Advantageously, providing a silica concentration within the range taught by Yoo provides a pure silica solution that is concentrated enough to prepare aerogels while being dilute enough to easily perform ion exchange (Pg. 7, par. 1).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to provide an aqueous silica precursor with a silica concentration between 5-15% by weight in the process of Gan in order to provide a pure silica solution that is concentrated enough to prepare aerogels while being dilute enough to easily perform ion exchange, as taught by Yoo.
Regarding claim 18, Gan teaches the method of claim 1 and Gan in view of Yoo teach the method of claim 3.
Gan further teaches the alcohol is a lower alcohol being a C1-C3 monohydric, including ethanol (Claim 1; [0012]; [0024]).
Claims 5-6, 9, 11-12, 16, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Kim et al. (WO2017155311A1 English Translation).
Regarding claim 5, Gan teaches the method of claim 1.
The claim further requires “pH adjustment is carried out by adding an inorganic acid selected from hydrochloric acid, nitric acid, sulphurous acid, and oxalic acid, and mixtures thereof” to which Gan teaches the acid is glacial acetic acid (Claim 1).
Kim teaches a method to prepare hydrophobic silica airgel materials by a procedure where a silica sol is mixed with an aerogel powder capable of applying hydrophobic surface modification prior to initiating gelation that includes preparing an airgel precursor by mixing airgel powder with an acidic silica sol with a pH of 0.5 to 1 (Abstract; Pg. 6, par. 8-28). Kim further teaches the pH is adjusted with acidic catalysts that may include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and the like (Pg. 6), while teaching an example using hydrochloric acid (Pg. 11, Example One).
Advantageously, providing an acid taught by Kim produces an airgel material that displays high-temperature hydrophobicity and durability (Pg. 6, par. 16-18).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and the like in the process of Gan in order to provide an airgel material with high-temperature hydrophobicity and durability, as taught by Kim.
Regarding claim 6, Gan teaches the method of claim 1 and Gan in view of Kim teach the method of claim 5.
The claim further requires “the concentration of the inorganic acid is between 0.1 and 0.2 mol/L” to which Gan is silent.
Kim teaches a method to prepare hydrophobic silica airgel materials by a procedure where a silica sol is mixed with an aerogel powder capable of applying hydrophobic surface modification prior to initiating gelation that includes preparing an airgel precursor by mixing airgel powder with an acidic silica sol with a pH of 0.5 to 1 (Abstract; Pg. 6, par. 8-28). Kim further teaches the pH is adjusted with acidic catalysts that may include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and the like (Pg. 6), while teaching an example using hydrochloric acid (Pg. 11, Example One). Kim teaches an example where the hydrochloric acid catalyst is 0.15% (Pg. 11, Example One). A 0.15% HCl solution is equivalent to a 0.15 N HCl solution (normality), which, in the case of HCl, is equivalent to a 0.15 M solution of HCl. Normality and molarity are equivalent when the number of equivalents of reactive chemical functionalities are equal to 1. In the case of HCl, there is one active proton and therefore HCl normality is equal to molarity.
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Kim (0.15 M (mol/L)) overlaps with the claimed range (0.1 and 0.2 mol/L). Therefore, the range in Kim renders obvious the claimed range.
Advantageously, providing an acid taught by Kim produces an airgel material that displays high-temperature hydrophobicity and durability (Pg. 6, par. 16-18).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and the like at concentration of 0.15 mol/L in the process of Gan in order to provide an airgel material with high-temperature hydrophobicity and durability, as taught by Kim.
Regarding claim 9, Gan teaches the method of claim 1.
The claim further requires “the organosilane is included in the amount of 1 - 50 wt. % of the wet gel” to which Gan teaches a volume ratio ([0014]).
Kim teaches the airgel powder may be used in an amount of 25 parts by weight to 50 parts by weight based on 100 parts by weight of silica contained in the silica sol (Pg. 8). Kim further teaches an example where airgel powder was mixed with 140 ml of the prepared silica sol in an amount of 25 parts by weight based on 100 parts by weight of the silica in the silica sol to prepare an airgel precursor (Pg. 11, Example One). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Kim (25 parts by weight to 50 parts by weight based on 100 parts by weight of silica contained in the silica sol) overlaps with the claimed range (organosilane is included in the amount of 1 - 50 wt. % of the wet gel). Therefore, the range in Kim renders obvious the claimed range.
Advantageously, providing a hydrophobizing organosilane between 25 parts by weight to 50 parts by weight based on 100 parts by weight of silica contained in the silica sol provides whole or partial silylation of the surface groups that imparts permanent hydrophobicity to the airgel material (Pg. 8).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to provide an organosilane concentration of 25 parts by weight to 50 parts by weight based on 100 parts by weight of silica contained in the silica sol in the process of Gan in order to impart permanent hydrophobicity to the airgel material, as taught by Kim.
Regarding claim 11, Gan teaches the method of claim 1. The claim further requires “the basic solution is an ammonia solution having a concentration between 0.1 and 2 mol/L” to which Gan does not state the ammonia solution concentration.
Kim teaches a general volume percentage of basic ammonia catalyst of 0.05 to 10% by volume (Pg. 9), while teaching an example using 0.5% by volume ammonia solution (Pg. 11, Example One). Conversion of the volume percentage to molarity gives a general range of 0.021 to 4.3 mol/L, and a working example of 0.17 mol/L. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Kim (0.021 to 4.3 mol/L ammonia solution) overlaps with the claimed range (between 0.1 and 2 mol/L). Therefore, the range in Kim renders obvious the claimed range.
Calculations:
Molarity = (Percentage concentration × Density ) / (Molar mass × 100)
Ammonia molar mass = 17.031 g/molDensity = 0.73 g/cm3molarity for 0.5 volume % in Example One:M = (0.5 x 0.73)/ (17.031 * 100) = 0.17 mol/L
Advantageously, providing the basic ammonia catalyst in the concentration of Kim enables adjustment of the pH of the mixture to promote gelation (Pg. 9, par. 6-8).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to provide a basic ammonia catalyst at a concentration from 0.021 to 4.3 mol/L in the process of Gan in order to enable gelation to occur by adjusting the pH, as taught by Kim.
Regarding claim 12, Gan teaches the method of claim 1.
Gan further teaches washing is carried out prior to drying (Abstract).
The claim further requires the washing is carried out “prior to contacting the wet gel with a supercritical fluid” to which Gan does not teach the drying is performed with supercritical fluid.
Kim teaches the hydrophobic airgel material can be dried with supercritical liquid CO2 (Pg. 9, par. 18-23; Pg. 11, Example One).
Advantageously, performing drying with supercritical CO2 allows for high drying efficiency and short drying time (Pg. 9, par. 18-23).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to perform supercritical drying with liquid CO2 in the process of Gan in order to achieve high drying efficiency in short drying time, as taught by Kim.
Regarding claim 16, Gan teaches the method of claim 1.
The claim further requires “wherein prior to mixing the aqueous silica precursor, the aqueous silica precursor is pretreated by passing an aqueous solution of the aqueous silica precursor containing between 4 and 31 wt. % SiO2 through an ion exchanger resin” to which Gan teaches filtration of a silica sol prior to mixing the aqueous silica precursor ([0024]) however Gan is silent regarding passing through an ion exchanger with the claimed concentration.
Kim teaches the preparation of a hydrophobic airgel powder where the silica precursor can be treated with an acid ion exchange resin to prepare silicic acid (Pg. 7), including an example where sodium water glass solution is passed through a sulfonic acid resin to provide a silica content of 6 % by weight (Pg. 12, Example 6). A water glass solution contains water and is equivalent to an aqueous solution. Further, it would have been obvious to substitute the hydrochloric acid catalyst in example one of Kim with the acidic ion exchange resin to prepare silicic acid as each method provides silicic acid with SiO2 concentration and pH values effect to prepare hydrophobic aerogels (e.g. Pg. 12, Example 4, SiO2 of 7 wt.%; pH at 2.7). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Kim (silica content of 6 % by weight) overlaps with the claimed range (between 4 and 31 wt. % SiO2). Therefore, the range in Kim renders obvious the claimed range.
Advantageously, passing the silica precursor through an ion exchange resin controls the pH so that the resulting silica precursor solution can undergo polycondensation to form a gel with a base (Pg. 7, par. 10-16).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to pass a silica precursor with about 6 wt.% silica through an ion exchange resin in the process of Gan in order to adjust the pH so that the silica precursor can undergo gelation, as taught by Kim.
Regarding claim 22, Gan teaches the method of claim 1.
The claim further requires “wherein prior to step i), the aqueous silica precursor is pretreated by passing an aqueous solution of the aqueous silica precursor containing between 4 and 31 wt. % SiO2 through an ion exchanger resin” to which Gan teaches filtration of a silica sol prior to mixing the aqueous silica precursor ([0024]) however Gan is silent regarding passing through an ion exchanger with the claimed concentration.
Kim teaches the preparation of a hydrophobic airgel powder where the silica precursor can be treated with an acid ion exchange resin to prepare silicic acid (Pg. 7), including an example where sodium water glass solution is passed through a sulfonic acid resin to provide a silica content of 6 % by weight (Pg. 12, Example 6). A water glass solution contains water and is equivalent to an aqueous solution. Further, it would have been obvious to substitute the hydrochloric acid catalyst in example one of Kim with the acidic ion exchange resin to prepare silicic acid as each method provides silicic acid with SiO2 concentration and pH values effect to prepare hydrophobic aerogels (e.g. Pg. 12, Example 4, SiO2 of 7 wt.%; pH at 2.7). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Kim (silica content of 6 % by weight) overlaps with the claimed range (between 4 and 31 wt. % SiO2). Therefore, the range in Kim renders obvious the claimed range.
Advantageously, passing the silica precursor through an ion exchange resin controls the pH so that the resulting silica precursor solution can undergo polycondensation to form a gel with a base (Pg. 7, par. 10-16).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to pass a silica precursor with about 6 wt.% silica through an ion exchange resin in the process of Gan in order to adjust the pH so that the silica precursor can undergo gelation, as taught by Kim.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Amiri et al. (Colloids and Surfaces A, Physicochem. Eng. Aspects 2011, 378, 14-21).
Regarding claim 10, Gan teaches the method of claim 1.
The claim further requires “the synthesis and gelling are carried out at a controlled temperature and pressure between 15 and 30 °C and 1 and 200 bar, respectively,” to which Gan is silent.
Amiri teaches the effect of temperature and pressure on the stability and gelation properties of silica suspensions, where temperatures between 18 to 35 °C and pressures from 1 to 150 bars were tested (Title; Abstract; Fig. 1, Table 1, Fig. 7). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Amiri (temperatures between 18 to 35 °C and pressures from 1 to 150 bars) overlaps with the claimed range (temperature and pressure between 15 and 30 °C and 1 and 200 bar, respectively.). Therefore, the range in Amiri renders obvious the claimed range.
Advantageously, increasing temperatures over the range resulted in reduced gelation time while increasing pressures over the range resulted in enhanced shear thickening behavior (Abstract; Conclusions).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to perform the synthesis and gelation at temperatures between 18 to 35 °C and pressures from 1 to 150 bars in the process of Gan in order to reduce gelation time and enhance shear thickening as taught by Amiri.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Kim et al. (WO2017155311A1 English Translation) and further in view of Evans et al. (US20160096949A1).
Regarding claim 13, Gan teaches the method for preparing a hydrophobic silica aerogel of claim 1 and Gan in view of Kim teach the method of claim 12.
The claim further requires “the washing is carried out with ethanol at a temperature and pressure between 20 and 50 °C and 1 and 200 bar, respectively,” to which Gan and Kim are silent.
Evans teaches methods to prepare hydrophobic silica aerogel materials (Title; Abstract) where the hydrophobic silica aerogel material is washed with ethanol at 45 °C under ambient pressure ([0070]; [0131]). Evans does not teach the washing step is pressurized or manipulated outside of standard pressure conditions (i.e. 1 atmosphere, 1.01 bar), which meets the instant case pressure between 1 and 200 bar. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Evans (45 °C at 1.01 bar) overlaps with the claimed range (temperature and pressure between 20 and 50 °C and 1 and 200 bar, respectively.). Therefore, the range in Evans renders obvious the claimed range.
Advantageously, washing removes unreacted compounds and reaction by-products ([0047]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to wash the hydrophobic aerogel with ethanol at 45 °C at 1.01 bar in the process of Gan in order to remove unreacted compounds and reaction by-products as taught by Evans.
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Gan et al. (CN1636871A English; cited in IDS dated 02/17/2026) in view of Evans et al. (US20160096949A1).
Regarding claim 24, Gan teaches a method of preparing a hydrophobic silica aerogel by first mixing a methyltrialkoxysilane, a lower alcohol, water and a silica sol in a closed container and adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution for gelation to provide an alcohol-wet gel that is then dried after washing to obtain the hydrophobic silica aerogel (Abstract; Claim 1; [0023]-[0028]). Gan teaches the silica sol is colloidal silica prepared with neutral or alkaline water solution (Pg. 3, par. 1-3; Pg. 3-4, Examples 1-3). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Gan (pH 4-6) overlaps with the claimed range (pH between 0 and 5). Therefore, the range in Gan renders obvious the claimed range.
Gan teaches the reaction is performed in a sealable container and describes the mixing of methyltrialkoxysilane, lower alcohol, water and silica sol in a closed container, adjusting the pH value to between 4-6 followed by adjusting the pH to between 7 to 10 with an ammonia water solution initiates gelation that provides an alcohol-wet gel occurring within the same container (Abstract; Pg. 3-4, Example 1). Accordingly, Gan sufficiently describes the reaction as occurring in a single, sealable container which meets the limitation “wherein steps i), ii) and iii) occur in the same reactor.”
Gan further teaches the organosilane is selected from methyltrialkoxysilanes with the general formula CH3-Si(OR)3, where R is methyl or ethyl, while teaching examples using methyltrimethoxysilane (Pg. 3, par. 3; Pg. 3-4, Examples 1-3).
Gan differs from the instant claim in that Gan adds silica sol, ethanol, and deionized water to the methyltrialkoxysilanes prior to pH adjustment to a pH between 4-6 (See Pg. 3, Examples 1-3), while the instant invention requires adding the organosilane to the mixture of aqueous silica precursor and alcohol, where the mixture of aqueous silica precursor and alcohol has had its pH adjusted to between 0 to 5.
However, the selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results. See MPEP 2144.04.IV.C. Applicant has not provided data dismissing the Examiner’s conclusion of a distinguishing technical effect regarding the criticality of the order of addition. Given that Gan teaches the technical solution of providing the organosilane with the silica precursor during gelation according to claim 1, rather than performing hydrophobization after gelation, the process of Gan is considered relevant to the instantly claimed method.
Further, Gan teaches the advantageous effect of the process includes “In the initial stage of the reaction, a silylating agent (methyltrialkoxysilane) is added to the reactants for preparing the wet gel, so that the silylation reaction on the surface of the gel is in the gel of the sol. It can be carried out during the silylation process, which ensures the complete silylation reaction on the surface of the gel, improves the work efficiency, reduces the process flow, and realizes the preparation method of one-step synthesis of hydrophobic SiO2 airgel” (Pg. 3, par. 4).
The instant invention asserts hydrophobization throughout the gel is a substantially distinguishing technical effect (See Pg. 12 of the Remarks filed 09/10/2025) and that condensation of the silica precursor and organosilane during gelling achieve the homogenous hydrophobized gel matrix of the instant invention (see Pg. 17 of the Remarks filed 02/17/2026). Accordingly, a skilled artisan seeking to achieve the technical effect of obtaining complete silylation of the gel surface with the advantageous effects of improving the work efficiency and reducing the process flow would be motivated by the process of Gan despite the noted difference is the order of performing process steps.
The claim further requires “the aqueous silica precursor is a sodium silicate solution,” to which Gan teaches the silica soli is colloidal silica.
Evans teaches a method to prepare hydrophobic silica aerogel materials that includes mixing aqueous sodium silicate with a hydrophobizing agent and adjusting pH with acid prior to performing gelation ([0041]; [0093]-[0096]; [0121]-[0124]; [0126]-[0128]).
Advantageously, using sodium silicate as a precursor provides an alternative method of forming an aerogel while providing a flexible, resilient, and self-supporting material with favorable performance in aqueous environments ([0002]-[0003]; [0041]; [0047]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use aqueous sodium silicate in the process of Gan in order to provide an alternative method of preparing aerogels that still provides flexible, resilient, and self-supporting material with favorable performance in aqueous environments as taught by Evans.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/JORDAN W TAYLOR/Examiner, Art Unit 1738
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