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 .
DETAILED ACTION
Claims 1-32 of R. Chowdhury, US 18/636,681 (Apr. 16, 2024) are pending. Claims 21-32 drawn to non-elected Group (II) are withdrawn from consideration pursuant to 37 CFR 1.142(b). Claims 1-20 are under examination on the merits and are rejected.
Election/Restrictions
Pursuant to the restriction requirement, Applicant elected Claims 1-20, with traverse, drawn to method of making a hydrophobic silica aerogel, in the response filed on December 15, 2025. Claims 21-32 drawn to non-elected Group (II) are withdrawn from consideration pursuant to 37 CFR 1.142(b). The restriction requirement is made FINAL
Claim Rejections - 35 USC § 112(d)
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
§ 112(d) Rejections
Claims 11-15 are rejected under 35 U.S.C. 112(d) as being of improper dependent form for failing to further limit the subject matter of claim 1 upon which they depend, or for failing to include all the limitations of claim 1 upon which they depend, for the following reasons.
Base claim 1 recites
Claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
However, its dependent claim 11 recites:
11. The method of claim 1 wherein the density of the hydrophobic silica aerogel is between 120 mg/cc and 150 mg/cc and
the total weight percent of the tetramethyl orthosilicate is greater than or equal to 16.9% and less than or equal to 24.7% and
the total weight percent of the methyltrimethoxysilane is greater than or equal to 2.9% and less than or equal to 3.9%.
The claim 11 range respecting methyltrimethoxysilane (as underlined above) does not fall within the claim 1 range. As such, claim 11 is directed to compositions that fall outside the scope of claim 1. Claim 11 therefore fails to further limit the subject matter of the claim upon which it depends, or for fails to include all the limitations of the claim upon which it depends.
Dependent claims 12-15 (dependent upon claim 11) also recite methyltrimethoxysilane ranges that do not fall within the claim 1 range. Claims 12-15 are thus also improper under § 112(d) for the same reasons.
Claim Rejections - 35 USC § 103
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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under AIA 35 U.S.C. 103(a) 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.
Claims 1-20 are rejected under AIA 35 U.S.C. 103 as being unpatentable over F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”) in view of A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”) and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”).
F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”)
Schwertfeger teaches that organo-substituted alkogels can be obtained by base catalyzed hydrolysis and condensation, for example of mixtures of tetramethoxysilane, Si(OMe)4, and organo(trimethoxy)silanes, RSi(OMe)3, and the corresponding SiO2, aerogels can be obtained therefrom by subsequent super critical drying, for example with methanol, according to the following equation:
PNG
media_image1.png
200
400
media_image1.png
Greyscale
Schwertfeger at col. 2, lines 37-49. Schwertfeger teaches that any ratio of x to y is possible, but the ratio is preferably from 0:1 to 2:3 (i.e. 0 to 0.66) for achieving the desired combination of properties. Schwertfeger at col. 2, lines 54-56.
Schwertfeger teaches that the reagent amounts (i.e. above variables x, y, and z) are result effective variables with respect to the density of the SiO2 aerogel as follows:
PNG
media_image2.png
200
400
media_image2.png
Greyscale
Schwertfeger at col. 2, lines 56-67.
In working Examples 1-9 Schwertfeger teaches that 100 ml of organically modified SiO2, aerogels were prepared according to the above equation by adding a calculated amount of aqueous 0.01 N ammonia solution to a mixture of RSi(OMe)3 + Si(OMe)4 + methanol, where after mixing, the batch was allowed to stand in a closed vessel at room temperature until gelling occurred. Schwertfeger at col. 5, lines 50-64. Then, after the gel point had been reached, the gels were aged by storage in a closed vessel for 7 days at 30° C. Schwertfeger at col. 5, lines 65-66. After the ageing, the gels were subjected to supercritical drying with methanol as described in DE1811353A (corresponding to US 3,672,833 (1972)). Schwertfeger at col. 6, lines 1-2.
Schwertfeger Working Examples 2, 3 and 8 (which use the same reagents as instantly claimed) are summarized by the Examiner as follows:
Schematic Summary of Schwertfeger Working Examples 2, 3, and 8
PNG
media_image3.png
200
400
media_image3.png
Greyscale
Schwertfeger at col. 5, line 50 – col. 6, line 2.
Per Table 1, Schwertfeger teaches that the reagent amounts in Examples 2, 3, and 8 are as follows:
Reagent Amounts Schwertfeger Example 2
Component
weight
Total Wt.%
Claim 11
MTMS(x)
8.99 g
9.7%
3.2% -4.6%
TMOS (y)
40.19 g
43.2%
13.8% - 31%
MeOH
21.20 g
NH4OH/water
22.57 g
Total
92.95 g
*Molar Ratio of MTMS(x) (66 mmol) to TMOS (y) (264 mmol) = 0.25
Reagent Amounts Schwertfeger Example 3
Component
weight
Total Wt.%
Claim 1
MTMS(x)
18.12 g
19.6%
3.2% -4.6%
TMOS (y)
30.44 g
32.9%
13.8% - 31%
MeOH
22.44 g
NH4OH/water
21.58 g
Total
92.58
*Molar Ratio of MTMS(x) (133 mmol) to TMOS (y) (200 mmol) = 0.67
Reagent Amounts Schwertfeger Example 8
Component
weight
Total Wt.%
Claim 1
MTMS(x)
20.44 g
7.4%
3.2% -4.6%
TMOS (y)
91.34 g
33.5 %
13.8% - 31%
MeOH
109.50 g
NH4OH/water
51.30 g
Total
272.58
*Molar Ratio of MTMS(x) (150 mmol) to TMOS (y) (600 mmol) = 0.25
Schwertfeger at col. 7, Table 1
Differences between Schwertfeger and Claim 1
A first difference between Schwertfeger and claim 1 is reagent order addition. That is, claim 1 requires forming a first solution of tetramethyl orthosilicate (TMOS) and methanol, adding aqueous ammonium hydroxide (the claimed second solution) to this first TMOS solution, then adding a methyltrimethoxysilane (MTMS) /methanol solution (the claimed third solution) to the TMOS/ammonium hydroxide solution.
This claim 1 reagent-order addition is summarized as follows:
Examiner Summary of Claim 1
PNG
media_image4.png
200
400
media_image4.png
Greyscale
On the other hand, Schwertfeger prepares a first solution of TMOS/MTMS/MeOH and then adds the ammonium hydroxide (second solution) directly thereto.
Schwertfeger further differs from claim 1 in that Schwertfeger does not teach the specific claim 1 MTMS and TMOS reagent amounts:
Claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”)
Rao teaches that aerogels can be made as both transparent (>90%) and translucent to the visible light, depending on the sol–gel processing conditions, but they exhibit Rayleigh scattering in the blue region. Rao at page 268, col. 1. Rao teaches that these properties of aerogels can be utilized for thermal superinsulations in windows and heat-storage systems, acoustic devices, luminescent solar systems, gas filters, catalysts or catalyst supports. Rao at page 268, col. 1.
Rao teaches a study regarding effects of adding methyltrimethoxysilane (MTMS) to the synthesis formulation on the hydrophobicity and physical properties of silica aerogels. Rao at Abstract. Rao teaches that the molar ratio of the methanol (MeOH) solvent, water (H2O), and the ammonia (NH4OH) catalyst to tetramethoxysilane (TMOS) precursor was fixed at 1 TMOS : 12 MeOH : 4 H2O : 3.6×10−3 NH4OH throughout the experiment and the MTMS/TMOS molar ratio M was varied from 0 to 1.55. Rao at Abstract.
Rao teaches that for M<0.26 the aerogels were less hydrophobic but more transparent (>90% in the visible range), whereas for M>1.03 the aerogels were more hydrophobic but semi-transparent to opaque. Rao at Abstract. Rao further teaches that aerogels with good hydrophobicity and transparency (~85% in the visible range) were obtained with an M about 0.70 and an increase in the MTMS content in the gels shifted the pore size distribution towards larger pore radii with a broad distribution. Rao at Abstract.
Rao thus teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application.
A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”)
Pierre discusses base catalyzed reaction of TMOS and MTMS to give hydrophobic aerogels. Pierre at page 4254. Pierre teaches that as the hydrolysis and condensation rates of MTMS are much lower than those of TMOS, a quasi two-step gelation process is achieved and that this was shown by Hüsing et al., to occur in two-steps: first, the TMOS reacts and then the MTMS is grafted through the silanol surface groups of the gel giving surface Si-O-Si-CH3 functions. Pierre at page 4254, col. 1 (citing N. Hüsing et al., 10 Chemistry of Materials, 3024-3032 (1998)).
Obviousness Rationale
Claim 1 is obvious for the following reasons. The claimed order of reagent addition does not distinguish claim 1 from Schwertfeger under § 103, rather it is merely a design choice having no material effect on the reaction. MPEP § 2144.04(IV)(C).2 in this regard, Schwertfeger teaches generally that:
Organo-substituted alkogels can be obtained by base catalyzed hydrolysis and condensation, for example of mixtures of tetramethoxysilane, Si(OMe)4, and organo(trimethoxy)silanes, RSi(OMe)3, and the corresponding SiO2, aerogels can be obtained therefrom by subsequent super critical drying, for example with methanol.
Schwertfeger at col. 2, lines 37-41.
One of ordinary skill would understand from reference Pierre that in Schwertfeger’s process the hydrolysis and condensation rates of MTMS are much lower than those of TMOS, and a quasi-two-step gelation process occurs in two-steps: first, the TMOS self-condenses and then the MTMS is grafted through the silanol surface groups of the gel giving surface Si-O-Si-CH3 functions. Pierre at page 4254, col. 1. As such, one of ordinary skill would understand that addition order of MTMS and TMOS is not particularly relevant, and that the claimed addition order would give the same result as the order taught by Schwertfeger. In sum, neither the specification nor the art to sets forth any reasons why the order of reagent addition results in a different function or solves any stated problem.3 Thus, for example, one of ordinary skill is motivated to modify Schwertfeger’s reagent addition order so as to arrive at the claim 1 addition order depending upon convenience in obtaining reagents as methanol solutions, shipping considerations, etc.
Respecting the reagent concentration differences between Schwertfeger and claim 1, absent a showing of criticality or unexpected results, the further concentration differences recited in claim 1 also do not distinguish over the cited art.4 As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application.5 MPEP § 2144.05. For instance, one of ordinary skill is motivated to modify/optimize Schwertfeger by decreasing the amount of MTMS in order to increase the transparency of the aerogel; for example, one of ordinary skill seeking hydrophobic aerogels in applications where higher transparency is desired, such as thermal superinsulations in windows, as taught by Rao. In this regard, Rao teaches that lowering the MTMS/TMOS molar ratio provides aerogels with increased transparency. Rao at Abstract. For instance, one of ordinary skill is motivated to modify Schwertfeger Example 3 by lowering the MTMS/TMOS molar ratio and also using about the same molar ratios of MeOH, water and NH4OH as taught by Rao (Rao at Abstract) as follows (where the strikeout/bolded text indicates the proposed modification), thereby arriving at each and every limitation of claim 1.
Proposed Modified Reagent Amounts Schwertfeger Example 3
Component
weight
Total Wt.%
MTMS(x)
5.5 g (0.04 mol)
4.3%
TMOS (y)
30.44 g (0.200 mol)
23.9%
MeOH
76.8 g (2.4 mol)
60.4%
NH4OH/water
(0.01 N ammonia sol.)
14.4 g (0.8 mol) water having
0.045 g (0.00136 mol) NH4OH
11% water
0.035% NH4OH
Total
127.79 g
*Molar Ratio of MTMS(x) to TMOS (y) = 0.22
Here, the proposed molar Ratio of MTMS(x) to TMOS (y) = 0.22 which falls within Schwertfeger’s range 0:1 to 2:3 (i.e. 0 to 0.66) for achieving the desired combination of properties. Schwertfeger at col. 2, lines 54-56. And 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).
The concentration limitations of claims 2 and 3 are met by the above proposed modification.
Claim 4 is obvious for the following reasons.
4. The method of claim 1 wherein
the first solution comprises
tetramethyl orthosilicate at a weight percent of greater than or equal to 38.1 % and less than or equal to 68.4% and
methanol at a weight percent of greater than or equal to 31.6% and less than or equal to 61.9%,
the second solution comprises
methanol at a weight percent of greater than or equal to 54.9% and less than or equal to 65.7%,
water at a weight percent of greater than or equal to 33.9% and less than or equal to 44.7%, and
ammonium hydroxide at a weight percent of greater than or equal to 0.10% and less than or equal to 0.42%, and
the third solution comprises
methanol at a weight percent of greater than or equal to 84.5% and less than or equal to 89.2% and
methyltrimethoxysilane at a weight percent of greater than or equal to 10.8% and less than or equal to 15.5%.
As discussed above, the order of reagent addition does not distinguish over the cited art. Here, claim 4 further limits claim 1 by dictating the amounts of methanol and component in each of the three solutions. Such, limitations cannot distinguish over the cited art because they are mere design choices that appear immaterial to the claimed reaction. See MPEP § 2144.04 (IV)(B) (citing In re Dailey, 357 F.2d 669, 149 USPQ 47 (CCPA 1966). Here neither the specification nor the art to sets forth any reasons why mixing specific amounts of methanol with specific amounts of the respective solution components results in a different function or solves any stated problem.6 The point is that one of ordinary skill understands from reference Pierre that that reagents may simply be combined in any fashion so that they may react to form an aerogel. As discussed above, Pierre teaches that in Schwertfeger’s process the hydrolysis and condensation rates of MTMS are much lower than those of TMOS, and a quasi-two-step gelation process occurs in two-steps: first, the TMOS self-condenses and then the MTMS is grafted through the silanol surface groups of the gel giving surface Si-O-Si-CH3 functions. Pierre at page 4254, col. 1. As such, one of ordinary skill would understand that reagent addition order and whether various reagents are first diluted with specific methanol amounts is not particularly relevant and the claimed addition protocol would give the same result as that taught by Schwertfeger.
Claim 5 is obvious for the same reasons as claim 4. Claim 5 similarly further limits claim 1 by dictating the amounts of methanol and component in each of the three solutions. Thus, (as with claim 4), these claim 5 limitations cannot distinguish over the cited art because they are mere design choices that appear immaterial to the claimed reaction. See MPEP § 2144.04. As stated for clam 4, neither the specification nor the art to sets forth any reasons why mixing specific amounts of methanol with specific amounts of the respective solution components results in a different function or solves any stated problem.
Claim 6 is obvious for the following reasons.
6. The method of claim 1 wherein the density of the hydrophobic silica aerogel is between 120 mg/cc and 200 mg/cc and
the total weight percent of the tetramethyl orthosilicate is greater than or equal to 16.9% and less than or equal to 31 %, and
the total weight percent of the methyltrimethoxysilane is greater than or equal to 2.6% and less than or equal to 4.6%.
The tetramethyl orthosilicate and methyltrimethoxysilane limitations of claim 6 are met by the above proposed modification of the cited art.
Respecting the claim 6 density limitation, as discussed above, Schwertfeger teaches that the reagent amounts (i.e. above variables x, y, and z) are result effective variables with respect to the density of the SiO2 aerogel as follows:
PNG
media_image1.png
200
400
media_image1.png
Greyscale
Schwertfeger at col. 2, lines 37-49.
PNG
media_image2.png
200
400
media_image2.png
Greyscale
Schwertfeger at col. 2, lines 56-67.
Because the proposed modification of Schwertfeger employs the same reagent amounts as claimed, the resulting aerogel will have the same claimed density. Once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). Each and every limitation of claim 6 is asserted to be met by the cited art. The point is that Schwertfeger teaches that reagent concentrations are optimizable, result-effective variables and one of ordinary skill is motivated to optimize to achieve the claimed densities in relevant applications of the aerogel. See footnote 5.
Claims 7-10 depend from claim 6 but otherwise are the same as claims 2-5. Claims 7-10 are obvious for the same reasons given above for claims 2-5; where the claim 6 density limitations met for the reasons given directly above.
Claim 11 is obvious for the following reasons.
11. The method of claim 1 wherein the density of the hydrophobic silica aerogel is between 120 mg/cc and 150 mg/cc and
the total weight percent of the tetramethyl orthosilicate is greater than or equal to 16.9% and less than or equal to 24.7% and
the total weight percent of the methyltrimethoxysilane is greater than or equal to 2.9% and less than or equal to 3.9%.
Respecting the reagent concentration differences between Schwertfeger and claim 11, absent a showing of criticality or unexpected results, the further concentration differences recited in claim 1 also do not distinguish over the cited art for the same reasons as claim 1. See footnote 5.
For instance, one of ordinary skill is motivated to modify Schwertfeger Example 3 by lowering the MTMS/TMOS molar ratio (to increase aerogel transparency) and also using about the same molar ratios of MeOH, water and NH4OH as taught by Rao (Rao at Abstract) as follows (where the strikeout/bolded text indicates the proposed modification), thereby arriving at each and every limitation of claim 1.
Proposed Modified Reagent Amounts Schwertfeger Example 3
Component
weight
Total Wt.%
MTMS(x)
4 g (0.029 mol)
3.2%
TMOS (y)
30.44 g (0.200 mol)
24.2%
MeOH
76.8 g (2.4 mol)
61.1%
NH4OH/water
(0.01 N ammonia sol.)
14.4 g (0.8 mol) water having
0.045 g (0.00136 mol) NH4OH
11.5% water
0.035% NH4OH
Total
125.64 g
*Molar Ratio of MTMS(x) to TMOS (y) = 0.15
Here, the proposed molar Ratio of MTMS(x) to TMOS (y) = 0.15 which falls within Schwertfeger’s range 0:1 to 2:3 (i.e. 0 to 0.66) for achieving the desired combination of properties. Schwertfeger at col. 2, lines 54-56.
Respecting the claim 11 density limitation, as discussed above with respect to claim 6, Schwertfeger teaches that the reagent amounts (i.e. above variables x, y, and z) are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. Because the proposed modification of Schwertfeger employs the same reagent amounts as claimed, the resulting aerogel will have the same claimed density. Once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). Each and every limitation of claim 11 is asserted to be met by the cited art.
The concentration limitations of claims 12 and 13 are met by the above proposed modification.
Claim 14 is obvious for the same reasons as claim 4. Claim 14 recites:
14. The method of claim 11 wherein
the first solution comprises
tetramethyl orthosilicate at a weight percent of greater than or equal to 44.2% and less than or equal to 58.4% and
methanol at a weight percent of greater than or equal to 41.6% and less than or equal to 55.8%,
the second solution comprises
methanol at a weight percent of greater than or equal to 61.1 % and less than or equal to 65%,
water at a weight percent of greater than or equal to 34.6% and less than or equal to 38.8%, and
ammonium hydroxide at a weight percent of greater than or equal to 0.10% and less than or equal to 0.38%, and
the third solution comprises
methanol at a weight percent of greater than or equal to 86.8% and less than or equal to 89.2% and
methyltrimethoxysilane at a weight percent of greater than or equal to 10.8% and less than or equal to 13.2%.
As discussed above, the order of reagent addition does not distinguish over the cited art. Here, claim 14 further limits claim 11 by dictating the amounts of methanol and component in each of the three solutions. Such, limitations cannot distinguish over the cited art because they are mere design choices that appear immaterial to the claimed reaction. See MPEP § 2144.04 (IV)(B) (citing In re Dailey, 357 F.2d 669, 149 USPQ 47 (CCPA 1966). Here neither the specification nor the art to sets forth any reasons why mixing specific amounts of methanol with specific amounts of the respective solution components results in a different function or solves any stated problem. See footnote 6. The point (as discussed above for claim 4) is that one of ordinary skill understands from reference Pierre that that reagents may simply be combined in any fashion so that they may react to form an aerogel.
Claim 15 is obvious for the same reasons as claim 14. Claim 15 similarly further limits claim 11 by dictating the amounts of methanol and component in each of the three solutions. Thus, (as with claim 14), these claim 15 limitations cannot distinguish over the cited art because they are mere design choices that appear immaterial to the claimed reaction. See MPEP § 2144.04. Here neither the specification nor the art to sets forth any reasons why mixing specific amounts of methanol with specific amounts of the respective solution components results in a different function or solves any stated problem.
Claim 16 is obvious because Schwertfeger teaches that after the gel point had been reached, the gels were aged by storage in a closed vessel for 7 days at 30° C. Schwertfeger at col. 5, lines 65-66. In this regard, teaches that after the gel point has been reached, the gels are generally aged by storage in a closed vessel for from 2 to 20 days at from 10° to 60° C., preferably for from 5 to 10 days at from 20° to 30° C. The suitable aging period can be determined by continuously determining the H2O/R'OH ratio in the gels, this ratio no longer changing after the end of the aging processes. Schwertfeger at col. 3, lines 7-12.
Respecting claim 17, Schwertfeger teaches that after aging, the gels are subjected to super-critical drying in a conventional manner (cf. for example U.S. Pat. No. 4,667,417). Schwertfeger at col. 3, lines 13-15. Schwertfeger teaches that a chemical reaction may occur between the solvents used for the supercritical drying (for example methanol) and the SiO2 (aero)gel, so that, for example in the case of methanol, O-methyl groups are formed. Schwertfeger at col. 3, lines 16-19. And in the working Examples, Schwertfeger teaches that after the ageing, the gels were subjected to supercritical drying with methanol as described in DE1811353A (corresponding to US 3,672,833 (1972)). Schwertfeger at col. 6, lines 1-2. Claim 17 is obvious because U.S. Pat. No. 4,667,417 teaches aerogel extraction with methanol for a time period of less than 24 hours. U.S. Pat. No. 4,667,417 at col. 2, lines 10-55.
Respecting claim 18, Schwertfeger teaches that, the Si2O, aerogels are kept, for example, at from 600° to 1300° C in the atmosphere of a chemically inert gas. Schwertfeger at col. 4, lines 1-3. Schwertfeger further teaches that during the pyrolysis, the volume of the SiO2, aerogels changes slightly due to shrinkage. Furthermore, as a result of removal of organic components, the mass of the samples decreases. This results in a small change in the density of the samples. Schwertfeger at col. 4, lines 41-45. The limitations of claim 18 are therefore met.
Claim 19 further limits claim 1 by reciting “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”. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application and that decreasing the amount of MTMS in increases the transparency of the aerogel. Rao at Abstract. Here the obviousness rationale proposes lowering the molar ratio M of MTMS/TMOS to arrive at hydrophobic aerogels in applications where higher transparency is desired, such as thermal superinsulations in windows, as taught by Rao. Because the proposed modification of Schwertfeger employs the same reagent amounts as claimed, the resulting aerogel will have the same claimed transmission and haze values as claimed. Once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). Each and every limitation of claim 19 is asserted to be met by the cited art. The point is that Rao teaches that molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable and one of ordinary skill is motivated to optimize this ratio to achieve the claimed transmission and haze values in relevant applications of the aerogel. See footnote 5.
Claim 20 is obvious because the proposed prior art modification involves no surfactant.
Non-Statutory Double Patenting Rejections
The non-statutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A non-statutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
Provisional Non-Statutory Double Patenting Rejection over R. Chowdhury et al., US 18/637,818 (2024), published as US 2025/0326219 (2025)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-14 of R. Chowdhury et al., US 18/637,818 (2024), published as US 2025/0326219 (2025) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented.
Conflicting claim 1 differs from instant claim 1 only in the following reagent amounts:
Conflicting claim 1 . . . wherein the tetramethyl orthosilicate and methyltrimethoxysilane are provided in a controlled amount selected to provide a molar ratio of tetramethyl orthosilicate: methyltrimethoxysilane of greater than or equal to 3.7:1 and less than or equal to 9.2:1.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. 7 As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-14. Instant claims 2-20 are patentably indistinct from conflicting claims 1-14 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Provisional Non-Statutory Double Patenting Rejection over R. Chowdhury et al., US 18/636,421 (2024), published as US 2024/0351313 (2024)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-13 of R. Chowdhury et al., US 18/636,421 (2024), published as US 2024/0351313 (2024) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented. However, the instant and conflicting claims have the same patent term filing date.
Conflicting claim 1 differs from instant claim 1 only in the following reagent percentages:
Conflicting claim 1 . . . 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.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-13. Instant claims 2-20 are patentably indistinct from conflicting claims 1-13 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Provisional Non-Statutory Double Patenting Rejection over R. Chowdhury et al., US 18/636,715 (2024), published as US 2024/0351326 (2024)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-20 of R. Chowdhury et al., US 18/636,715 (2024), published as US 2024/0351326 (2024) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented. However, the instant and conflicting claims have the same patent term filing date.
Conflicting claim 1 differs from instant claim 1 only in the following reagent percentages:
Conflicting claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 2.3% and less than or equal to 5.7% 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 and third solutions.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-20. Instant claims 2-20 are patentably indistinct from conflicting claims 1-20 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Provisional Non-Statutory Double Patenting Rejection over Chowdhury et al., US 18/638,006 (2024), published as US 2025/0326221 (2025)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-11 of R. Chowdhury et al., US 18/638,006 (2024), published as US 2025/0326221 (2025) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented. However, the instant and conflicting claims have the same patent term filing date.
Conflicting claim 1 differs from instant claim 1 only in the preamble and the recited reagent amounts:
Conflicting claim 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:
. . .
wherein the tetramethoxysilane and methyltrimethoxysilane are provided in a controlled amount selected to provide a molar ratio of tetramethoxysilane:methyltrimethoxysilane of greater than or equal to 3.86:1 and less than or equal lo 6.11:1.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-11. Instant claims 2-20 are patentably indistinct from conflicting claims 1-11 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Provisional Non-Statutory Double Patenting Rejection over R. Chowdhury et al., US 18/637,885 (2024), published as US 2025/0326648 (2025)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-14 of R. Chowdhury et al., US 18/637,885 (2024), published as US 2025/0326648 (2025) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented.
Conflicting claim 1 differs from instant claim 1 only in the following reagent percentages:
Conflicting claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 2.2% and less than or equal to 5.4% and
the methyltriethoxysilane has a total weight percent of greater than or equal to 1.2% and less than or equal to 1.5%,
wherein total weight percent represents a total weight percent of a component in the first, second, third and fourth solutions.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-14. Instant claims 2-20 are patentably indistinct from conflicting claims 1-14 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Provisional Non-Statutory Double Patenting Rejection over R. Chowdhury et al., US 18/638,201 (2024), published as US 2025/0326650 (2025)
Claims 1-20 are provisionally rejected on the ground of non-statutory double patenting as being unpatentable over conflicting claims 1-11 of R. Chowdhury et al., US 18/638,201 (2024), published as US 2025/0326650 (2025) in further view of F. Schwertfeger et al., US 5,587,107 (1996) (“Schwertfeger”), A. Rao et al., 30 Microporous and Mesoporous Materials, 267-273 (1999) (“Rao”), and A. Pierre et al., 102 Chemical Reviews, 4243-4265 (2002) (“Pierre”). The rejection is provisional because the conflicting claims have not been patented.
Conflicting claim 1 differs from instant claim 1 only in the preamble and the recited reagent amounts:
Conflicting claim 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:
. . .
wherein the tetramethoxysilane and methyltriethoxysilane are provided in a controlled amount selected to provide a molar ratio of tetramethoxysilane:methyltriethoxysilane of greater than or equal to 2.16: 1 and less than or equal to 4.3: 1.
Instant claim 1 . . . wherein the tetramethyl orthosilicate has a total weight percent of greater than or equal to 13.8% and less than or equal to 31 % and
the methyltrimethoxysilane has a total weight percent of greater than or equal to 3.2% and less than or equal to 4.6%,
wherein total weight percent represents a total weight percent of a component in the first, second and third solutions.
Respecting the reagent concentration differences between the instant and conflicting claims, absent a showing of criticality or unexpected results, the concentration differences do not distinguish over the conflicting claims in view of the cited art. As discussed above, Rao teaches that the molar ratio M of MTMS/TMOS is clearly an optimizable, result-effective variable depending on the physical properties desired in the respective application. MPEP § 2144.05. And Schwertfeger teaches that these reagent amounts are result effective variables with respect to the density of the SiO2 aerogel. Schwertfeger at col. 2, lines 37-67. One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Instant dependent claims 2-20 generally track conflicting claims 2-11. Instant claims 2-20 are patentably indistinct from conflicting claims 1-11 in view the above cited secondary art for the same reasons given in the above § 103 rejection.
Terminal Disclaimer
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER R PAGANO whose telephone number is (571)270-3764. The examiner can normally be reached 8:00 AM through 5:00 PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Scarlett Goon can be reached at 571-270-5241. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format.
For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
ALEXANDER R. PAGANO
Examiner
Art Unit 1692
/ALEXANDER R PAGANO/Primary Examiner, Art Unit 1692
1 The specification clarifies the meaning of the required claim 1 tetramethyl orthosilicate (TMOS) and methyltrimethoxysilane (MTMS) percentages as follows:
As used herein, "weight percent" refers to weight percent of a component in a single solution used to form hydrophobic wet gel (e.g., in the first solution, the second solution, the third solution).
Further, as used herein, "total weight percent" refers to total weight percent of a component used to form hydrophobic silica wet gel.
For example, if three solutions are used to form the hydrophobic silica wet gel, the total weight percent of a component is the total weight percent of that component in the combination of the first solution, the second solution and the third solution.
Specification at page 11, [0031].
2 MPEP § 2144.04 (IV)(C) (citing Ex parte Rubin, 128 USPQ 440 (Bd. App. 1959) (Prior art reference disclosing a process of making a laminated sheet wherein a base sheet is first coated with a metallic film and thereafter impregnated with a thermosetting material was held to render prima facie obvious claims directed to a process of making a laminated sheet by reversing the order of the prior art process steps.). See also In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946) (selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results); In re Gibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930) (selection of any order of mixing ingredients is prima facie obvious.).
3 See also, In re Rice, 341 F.2d 309, 314 (CCPA 1965) ("Appellants have failed to show that the [differences in the claimed invention], as compared to [ the reference], result in a difference in function or give unexpected results"); In re Kuhle, 526 F.2d 553, 555 (CCPA 1975) ("Use of such a means of electrical connection in lieu of those used in the references solves no stated problem and would be an obvious matter of design choice within the skill of the art."); In re Chu, 66 F.3d 292, 298-99 (Fed. Cir. 1995).
4 Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. MPEP § 2144.05(II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%.)).
5 One of ordinary skill is generally motivated to develop workable or optimum ranges for result-effective parameters, where Applicant can rebut a prima facie case of obviousness by showing the criticality (unexpected result) of the range. MPEP § 2144.05; see also, In re Boesch, 617 F.2d 272,276 (CCPA 1980); In re Aller, 220 F.2d 454, 456 (CCPA 1955).
6 See also, In re Rice, 341 F.2d 309, 314 (CCPA 1965) ("Appellants have failed to show that the [differences in the claimed invention], as compared to [ the reference], result in a difference in function or give unexpected results"); In re Kuhle, 526 F.2d 553, 555 (CCPA 1975) ("Use of such a means of electrical connection in lieu of those used in the references solves no stated problem and would be an obvious matter of design choice within the skill of the art."); In re Chu, 66 F.3d 292, 298-99 (Fed. Cir. 1995).
7 Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. MPEP § 2144.05(II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%.)).