Prosecution Insights
Last updated: April 19, 2026
Application No. 17/295,516

Use of CO2 as Water Demand Reducer in Gypsum Stucco Rehydration Mortars

Final Rejection §103§112
Filed
May 20, 2021
Examiner
ZHANG, KELING NMN
Art Unit
1732
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Knauf Gips Kg
OA Round
4 (Final)
67%
Grant Probability
Favorable
5-6
OA Rounds
3y 5m
To Grant
86%
With Interview

Examiner Intelligence

Grants 67% — above average
67%
Career Allow Rate
130 granted / 195 resolved
+1.7% vs TC avg
Strong +20% interview lift
Without
With
+19.8%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
43 currently pending
Career history
238
Total Applications
across all art units

Statute-Specific Performance

§103
49.3%
+9.3% vs TC avg
§102
14.8%
-25.2% vs TC avg
§112
26.2%
-13.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 195 resolved cases

Office Action

§103 §112
DETAILED ACTION Claim(s) 1-8 and 16-19 was/were rejected in Office Action mailed on 09/17/2025. Applicant filed a response, amended claim(s) 1-2, 4 and 17, canceled claim 16, and added claim(s) 21- 22 on 12/17/2025. Claim(s) 1-15 and 17-22 are pending, and claim(s) 9-15 and 20 are withdrawn. Claim(s) 1-8, 17-19 and 21-22 are rejected. 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 . Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim 21 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 21, line 1 and line 2 is amended to recite a phrase “continuously”. However, it is unclear that the phrases refer to, i.e., continuous for any given period of time, or continuous operation instead of a batch operation. The examiner interprets that the phrase refers to continuous for any given period time, given that the specification only provides support for forming of the gypsum article into the desired shape in a continuous operation, such as a moving conveyor (specification, page 8, bottom paragraph), and the specification does not provide support for the entire process of producing the gypsum article, including introducing carbon dioxide with stucco in a continuous operation, instead of batch operation. Interpretation is speculative. Clarification is requested. 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 (i.e., changing from AIA to pre-AIA ) 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. Claim(s) 1-4, 6-7 and 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Parkhurst, US 1620915 (Parkhurst) (provided in IDS received on 06/14/2021), in view of Loechl et al., US 2,965,528 (Loechl), and taken in view of evidence by Peng et al., The pH of CO2-saturated water at temperatures between 308 K and 423 K at pressures up to 15 MPa, The Journal of Supercritical Fluids, 2013 (Peng). Regarding claims 1-2, 4, and 17, Parkhurst teaches blocks or cakes formed from a mixture of calcined gypsum and water (Parkhurst, left column, 1st paragraph); the process comprising mixing carbon dioxide with calcined gypsum (i.e., stucco) and water (Parkhurst, page 2, left column, 3rd paragraph; claims 1-2); the supply of gas (i.e., carbon dioxide) is maintained during the mixing period of about three minutes (Parkhurst, page 2, right column, 1st paragraph). While Parkhurst teaches mixing carbon dioxide with calcined gypsum and water, however, it is noted that switching the order of performing process steps would be obvious absent any clear and convincing evidence and/or arguments to the contrary (see MPEP 2144.04 IVC). Therefore, it would have been obvious to one of ordinary skill in the art to perform the process steps in any order, including introducing a measured quantity of carbon dioxide into a process water, and subsequently, mixing stucco with the process water having the carbon dioxide introduced therein to form a slurry, given that it is clear that the same product would result, absent evidence to the contrary. 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.). Further regarding claim 1, in light of the above, Parkhurst teaches an identical or substantially identical method in Parkhurst, with an identical or substantially identical materials, (i.e., mix carbon dioxide with water, and mix calcined gypsum (i.e., stucco) with the water mixed with the carbon dioxide) as those of the presently claimed (specification, Example 1, claim 1), or alternatively, it would have been obvious to one of ordinary skill in the art to use an identical or substantially identical method in Parkhurst, with an identical or substantially identical materials, (i.e., mix carbon dioxide with water, and mix calcined gypsum (i.e., stucco) with the water mixed with the carbon dioxide) as those of the presently claimed (specification, Example 1, claim 1), therefore it is clear that the method of Parkhurst would necessarily and inherently meet the claimed limitation of wherein the addition of carbon dioxide to the process water results in a reduction of an amount of process water necessary to achieve a given fluidity of the slurry. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01 (I). Further regarding claims 1 and 4, Parkhurst does not explicitly disclose wherein the stucco is mixed with the process water having the carbon dioxide introduced therein to provide a water/stucco weight ratio in a range of about 0.5 to 0.8, or about 0.6 to 0.8. With respect to the difference, Loechl teaches manufacture of gypsum wallboard (Loechl, column 1, 1st paragraph). Loechl specifically teaches generally the amount of water to be added will be in the approximate amount of the weight of stucco, but depending upon the particular source of the gypsum rock and its processing, the water to be added may vary within the range of, say, from about 65 to about 120% of the weight of gypsum stucco; those skilled in the art, and particularly, those engaged in the manufacture of gypsum wallboard, will know, according to the quality of the gypsum stucco being used, approximately the amount of water necessary to be added, and will understand from the way in which the mixed slurry acts when discharged on the bottom sheet whether the content of water should be somewhat increased or decreased in order to have a properly handleable slurry (Loechl, column 5, lines 34-47). Loechl is analogous art as Loechl is drawn to manufacture of gypsum wallboard (Loechl, column 1, 1st paragraph). In light of the disclosure of Loechl, of the need to adjust water to stucco weight ratio, depending upon the particular source of the gypsum rock and its processing, and/or the need to produce a properly handleable slurry, it therefore would have been obvious to a person of ordinary skill in the art, to adjust water to stucco weight ratio, e.g., with water from about 65 to about 120% of the weight of gypsum stucco (i.e., a water/stucco weight ratio of 0.65 to 1.2), in order to produce a properly handleable slurry depending on particular source of the gypsum rock and its processing, and thereby arrive at a range that overlaps that of the presently claimed. As set forth in MPEP 2144.05, in the case where the claimed range “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists, In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). Further regarding claims 1-2 and 17, as applied to claim 1, Parkhurst in view of Loechl further teaches by mixing carbon dioxide with calcined gypsum (i.e., stucco) and water, the setting time of which is somewhat delayed; which will have adequate strength to permit handling and use immediately following removal from, the molds; which does not require any period of seasoning; which is of very much greater strength than prior gypsum products, and which is not so dependent upon accuracy of proportion of water and calcined gypsum (i.e., the introducing of carbon dioxide to the slurry is a result effective variable to various product performances of the gypsum product) (Parkhurst, page 2, left column, 3rd paragraph); injecting the carbon dioxide into the mixture for a period of not less than about three minutes (wherein the injecting time affects the amount of dissolved or dispersed carbon dioxide introduced into the mixture) (Parkhurst, Claim 5). Although there are no disclosures on the amounts of measured quantity of the carbon dioxide introduced into the process water and a concentration of dissolved or dispersed carbon dioxide in the process water, as presently claimed, it has long been an axiom of United States patent law that it is not inventive to discover the optimum or workable ranges of result-effective variables by routine experimentation. In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003) ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Boesch, 617 F.2d 272, 276 (CCPA 1980) ("[D]iscovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art."); In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."). "Only if the 'results of optimizing a variable' are 'unexpectedly good' can a patent be obtained for the claimed critical range." In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (quoting In re Antonie, 559 F.2d 618, 620 (CCPA 1977)). At the time of the invention, it would have been obvious to one of ordinary skill in the art to vary the amounts of injecting time of the carbon dioxide into the mixture, which would necessarily vary the concentration of dispersed carbon dioxide in the mixture, including over the amounts presently claimed, in order to achieve desirable performance of the gypsum product, e.g., setting time, and/or strength, and thereby arrive at the claimed invention. Regarding claim 3, as applied to claim 1, Parkhurst in view of Loechl teaches injecting carbon dioxide into water, as set forth above. According to Peng, CO2 (i.e., carbon dioxide) acidifies water (Peng, page 131, left column, section 2.2, 1st paragraph), therefore water injected with carbon dioxide would be acidified and have a pH value that is acidic (i.e., <7). Regarding claim 6, as applied to claim 1, Parkhurst does not explicitly disclose wherein a foam is mixed with the slurry, and wherein the addition of the carbon dioxide to the process water results in a reduction of the amount of foaming agent necessary to achieve a given density of the slurry. With respect to the difference, Loechl teaches manufacture of gypsum wallboard (Loechl, column 1, 1st paragraph). Loechl specifically teaches in some instances, through the addition of a surface tension reducing agent (reading upon a foaming agent) whereby, in the mixing, bubbles are incorporated in the mixture (reading upon a foam is mixed in the slurry) which is formed as the core of the board (Loechl, left column, 3rd paragraph). As Loechl expressly teaches, originally, gypsum wallboard was heavy, and due to its weight it was difficult to handle and, relatively expensive to ship; this originally heavy gypsum wall board has evolved into an appreciably lighter weight product; such product is now what might be termed the “standard product” of the gypsum wallboard industry, since, so far as it is known, all gypsum wallboard in the market is made by such general manufacturing procedures (e.g., through the addition of a surface tension reducing agent whereby, in the mixing, bubbles are incorporated in the mixture which is formed as the core of the board) (Loechl, left column, 3rd paragraph). Loechl is analogous art as Loechl is drawn to manufacture of gypsum wallboard (Loechl, column 1, 1st paragraph). In light of the motivation of incorporating bubbles in the mixture (reading upon a foam is mixed in the slurry), as taught by Loechl, it therefore would have been obvious to a person of ordinary skill in the art to through the addition of a surface tension reducing agent (reading upon a foaming agent) to the mixture of Parkhurst, whereby, in the mixing, bubbles are incorporated in the mixture of carbon dioxide, calcined gypsum and water (reading upon a foam is mixed in the slurry), in order to produce an appreciably lighter weight product, that is also cheaper to ship, as expected in “standard product” of the gypsum wallboard industry. Further regarding claim 6, given that Parkhurst in view of Loechl teaches an identical or substantially identical method, with an identical or substantially identical materials, (i.e., bubbles are incorporated in the mixture of carbon dioxide, calcium gypsum and water) as those of the presently claimed (specification, page 6, 3rd paragraph; claim 6), therefore it is clear that the method of Parkhurst would necessarily and inherently meet the claimed limitation of wherein the addition of the carbon dioxide to the process water results in a reduction of an amount of a foaming agent necessary to achieve a given density of the slurry. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01 (I). Regarding claim 7, as applied to claim 1, Parkhurst in view of Loechl further teaches the mixture, is drained off into molds in which it sets very promptly (reading upon formed to an article) (Parkhurst, page 2, right column, 1st paragraph). Regarding claims 18-19, as applied to claim 1, Loechl further teaches gypsum wall boards comprised merely a set gypsum mass between paper facings (Loechl, column 1, 2nd paragraph). In light of the disclosure of Loechl, it therefore would have been obvious to a person of ordinary skill in the art to manufacture the set mixture of calcined gypsum and water into gypsum wall boards, and yield expected results, and thereby arrive at the claimed inventions. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Parkhurst in view of Loechl as applied to claim 1 above, and further in view of Liu, WO 2006138001 A2 (Liu) (provided in IDS received on 06/14/2021). Regarding claim 5, as applied to claim 1, Parkhurst in view of Loechl does not explicitly disclose wherein prior to the mixing of the stucco with the process water having carbon dioxide introduced, paper pulp or additives are fed into the process water having carbon dioxide introduced. With respect to the difference, Liu teaches a method of making a gypsum slurry (Liu, Abstract). Liu specifically teaches a predissolved solution of a dispersant and modifier is prepared in water to form a solution prior to the addition of the stucco; after mixing the solution, the stucco is added to form the slurry (Liu, Abstract). As Liu expressly teaches, dispersants are known for use with gypsum that helps fluidize the mixture of water and calcium sulfate hemihydrate (i.e., calcined gypsum or stucco) so that less water is needed to make a flowable slurry (Liu, page 3, 2nd paragraph); modifiers can be added to a gypsum slurry to increase the efficacy of the dispersant (Liu, page 3, 3rd paragraph); the modifier has been shown to be less effective when added after the dispersant and stucco have been contacted in an aqueous slurry (Liu, Abstract); use of such a method (i.e., a predissolved solution of a dispersant and modifier is prepared in water to form a solution prior to the addition of the stucco) would keep the cost reasonable where expensive dispersants were used, and would minimize set retardation of the slurry (Liu, page 4, 1st paragraph). Liu is an analogous art, as Liu is drawn to a method of making a gypsum slurry (Liu, Abstract). In light of the motivation of incorporating dispersant and modifiers in making a gypsum slurry by preparing a predissolved solution of a dispersant and modifier in water to form a solution prior to the addition of the stucco, as taught by Liu, it therefore would have been obvious to a person of ordinary skill in the art to incorporate dispersant and modifiers in the mixture of carbon dioxide, calcined gypsum and water of Parkhurst in view of Loechl, by preparing a predissolved solution of a dispersant and modifier in water to form a solution prior to the addition of the stucco, in order to help fluidize the mixture of water and calcined gypsum and keep the cost reasonable where expensive dispersants were used, and/or minimize set retardation of the slurry, and thereby arrive at the claimed invention. Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Parkhurst in view of Loechl as applied to claim 7 above, and further in view of Liu. Regarding claim 8, as applied to claim 1, Parkhurst in view of Loechl does not explicitly disclose further comprising a step of drying the article or plasterboard. With respect to the difference, Liu specifically teaches the excess water is removed by evaporation (reading upon a step of drying) (Liu, page 2, 2nd paragraph). As Liu expressly teaches, when the product (i.e., a gypsum product formed from the gypsum slurry) is wet, it is very heavy to move and fragile (Liu, page 2, 2nd paragraph) In light of the motivation of removing excess water by evaporation from a gypsum product (reading upon drying), as taught by Liu, it therefore would have been obvious to a person of ordinary skill in the art to remove excess water from the gypsum product of Parkhurst (reading upon a step of drying), so the gypsum product is not very heavy to move or fragile, and thereby arrive at the claimed invention. Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Parkhurst. Regarding claim 21, Parkhurst teaches blocks or cakes formed (i.e., which would necessarily require forming these blocks and cakes for a period of time) from a mixture of calcined gypsum and water (Parkhurst, left column, 1st paragraph); the process comprising mixing carbon dioxide (i.e., which would necessary require introducing a measured quantity of carbon dioxide for a period of time) with calcined gypsum (i.e., stucco) and water (Parkhurst, page 2, left column, 3rd paragraph; claims 1-2); the supply of gas (i.e., carbon dioxide) is maintained during the mixing period of about three minutes (Parkhurst, page 2, right column, 1st paragraph). While Parkhurst teaches mixing carbon dioxide with calcined gypsum and water, however, it is noted that switching the order of performing process steps would be obvious absent any clear and convincing evidence and/or arguments to the contrary (see MPEP 2144.04 IVC). Therefore, it would have been obvious to one of ordinary skill in the art to perform the process steps in any order, including introducing a measured quantity of carbon dioxide into a process water, and subsequently, mixing stucco with the process water having the carbon dioxide introduced therein to form a slurry, given that it is clear that the same product would result, absent evidence to the contrary. 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.). In light of the above, Parkhurst teaches an identical or substantially identical method in Parkhurst, with an identical or substantially identical materials, (i.e., mix carbon dioxide with water, and mix calcined gypsum (i.e., stucco) with the water mixed with the carbon dioxide) as those of the presently claimed (specification, Example 1, claim 1), or alternatively, it would have been obvious to one of ordinary skill in the art to use an identical or substantially identical method in Parkhurst, with an identical or substantially identical materials, (i.e., mix carbon dioxide with water, and mix calcined gypsum (i.e., stucco) with the water mixed with the carbon dioxide) as those of the presently claimed (specification, Example 1, claim 1), therefore it is clear that the method of Parkhurst would necessarily and inherently meet the claimed limitation of wherein the addition of carbon dioxide to the process water results in a reduction of an amount of process water necessary to achieve a given fluidity of the slurry. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP 2112.01 (I). Parkhurst further teaches by mixing carbon dioxide with calcined gypsum (i.e., stucco) and water, the setting time of which is somewhat delayed; which will have adequate strength to permit handling and use immediately following removal from, the molds; which does not require any period of seasoning; which is of very much greater strength than prior gypsum products, and which is not so dependent upon accuracy of proportion of water and calcined gypsum (i.e., the introducing of carbon dioxide to the slurry is a result effective variable to various product performances of the gypsum product) (Parkhurst, page 2, left column, 3rd paragraph); injecting the carbon dioxide into the mixture for a period of not less than about three minutes (wherein the injecting time affects the amount of dissolved or dispersed carbon dioxide introduced into the mixture) (Parkhurst, Claim 5). Although there are no disclosures on the amounts of measured quantity of the carbon dioxide introduced into the process water and a concentration of dissolved or dispersed carbon dioxide in the process water, as presently claimed, it has long been an axiom of United States patent law that it is not inventive to discover the optimum or workable ranges of result-effective variables by routine experimentation. In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003) ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Boesch, 617 F.2d 272, 276 (CCPA 1980) ("[D]iscovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art."); In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."). "Only if the 'results of optimizing a variable' are 'unexpectedly good' can a patent be obtained for the claimed critical range." In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (quoting In re Antonie, 559 F.2d 618, 620 (CCPA 1977)). At the time of the invention, it would have been obvious to one of ordinary skill in the art to vary the amounts of injecting time of the carbon dioxide into the mixture, which would necessarily vary the concentration of dispersed carbon dioxide in the mixture, including over the amounts presently claimed, in order to achieve desirable performance of the gypsum product, e.g., setting time, and/or strength, and thereby arrive at the claimed invention. Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Parkhurst as applied to claim 21 above, and further in view of Loechl and Alan et a., ES 2642093 T3 (Alan). The examiner provides a machine translation of Alan et a., ES 2642093 T3 (Alan). The cited reference below refers to the machine translation. Regarding claim 22, as applied to claim 21, Parkhust does not explicitly disclose further comprising: continuously forming the article from the slurry containing the stucco and the process water having the carbon dioxide introduced therein. With respect to the difference, Loechl teaches gypsum wall boards comprised merely a set gypsum mass between paper facings (Loechl, column 1, 2nd paragraph); Alan teaches the gypsum wall board is typically manufactured as a continuous product in a continuous conveyor using rolls of paper coating material (Alan, page 3, 1st paragraph). Both Loechl and Alan are analogous art as both are drawn to manufacture of gypsum wallboard. In light of the disclosure of Loechl and Alan, it therefore would have been obvious to a person of ordinary skill in the art to manufacture the set mixture of calcined gypsum and water of Parkhurst into gypsum wall boards as a continuous product in a continuous conveyor, and yield expected results, and thereby arrive at the claimed inventions. Response to Arguments The amended necessitates a new set of 35 U.S.C. 112(b) rejection(s) as set forth above. Applicant primarily argues: “The Office Action states that "the present claim 1 does not require CO2 is added into a process water prior to mixing with the stucco" and that independent claim 1 only requires "introducing a measured quantity of carbon dioxide into a process water and mixing stucco with the process water having the carbon dioxide introduced therein to form a slurry." See pages 15- 17 of the Office Action. Applicant respectfully disagrees as the limitation reciting "mixing stucco with the process water having the carbon dioxide introduced therein" makes clear that carbon dioxide is added into the process water prior to mixing with the stucco. Nonetheless, the foregoing amendment to independent claim 1 recites "(a) introducing a measured quantity of carbon dioxide into a process water ... and (b) subsequent to step (a), mixing stucco with the process water having the carbon dioxide introduced therein to form a slurry". Parkhurst does not teach the introduction of carbon dioxide into the process water prior to combination of the process water with stucco.” Remarks, p. 7 The Examiner respectfully traverses as follows: Firstly, while Parkhurst teaches mixing carbon dioxide with calcined gypsum and water, however, it is noted that switching the order of performing process steps would be obvious absent any clear and convincing evidence and/or arguments to the contrary (see MPEP 2144.04 IVC). Therefore, it would have been obvious to one of ordinary skill in the art to perform the process steps in any order, including introducing a measured quantity of carbon dioxide into a process water, and subsequently, mixing stucco with the process water having the carbon dioxide introduced therein to form a slurry, given that it is clear that the same product would result, as set forth on page 4 of Office Action mailed 09/17/2025, absent evidence to the contrary. 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.). Secondly, in order to establish the criticality of the order, applicant is suggested to provide proper side-by-side comparison data. Applicant further argues: “Amended independent claim 1 also recites "(a) introducing a measured quantity of carbon dioxide into a process water to provide a concentration of dissolved or dispersed carbon dioxide in the process water of at least 1 g/L and no more than 15 g/L". As Parkhurst does not teach the introduction of carbon dioxide into the process water prior to combination of the process water with stucco, there is no teaching or suggestion in Parkhurst that the carbon dioxide, injected during the mixing of the water and the calcined gypsum in Parkhurst, is dissolved or dispersed in the water at a concentration of "at least 1 g/L and no more than 15 g/L." Rather, Parkhurst indicates that its method provides a product "of greater bulk per unit of calcined gypsum than has heretofore been obtainable" (Parkhurst at lines 30-32), which is a result of the "thick cream" (Parkhurst at line 73) produced in the process of Parkhurst. The "thick cream" results from CO2, which is not dissolved in the water, becoming entrapped in the gypsum slurry after mixing of the water and gypsum has already begun. Incorporating the CO2 into the water before the water is contacted with gypsum would compromise the formation of such "thick cream", which according to Parkhurst provides greater bulk per unit of calcined gypsum. Therefore, one of skill in the art would not have modified the teaching of Parkhurst, in view of Loechel or any other prior art references, to introduce a measured quantity of carbon dioxide at a concentration of at least 1 g/L and no more than 15 g/L into a process water prior to mixing with gypsum to reach the elements of amended independent claim 1.” Remarks, p. 7 The Examiner respectfully traverses as follows: Firstly, it is noted that switching the order of performing process steps would be obvious absent any clear and convincing evidence and/or arguments to the contrary, as set forth above. Secondly, Parkhurst further teaches by mixing carbon dioxide with calcined gypsum (i.e., stucco) and water, the setting time of which is somewhat delayed; which will have adequate strength to permit handling and use immediately following removal from, the molds; which does not require any period of seasoning; which is of very much greater strength than prior gypsum products, and which is not so dependent upon accuracy of proportion of water and calcined gypsum (i.e., the introducing of carbon dioxide to the slurry is a result effective variable to various product performances of the gypsum product) (Parkhurst, page 2, left column, 3rd paragraph); injecting the carbon dioxide into the mixture for a period of not less than about three minutes (wherein the injecting time affects the amount of dissolved or dispersed carbon dioxide introduced into the mixture) (Parkhurst, Claim 5). Although there are no disclosures on the amounts of measured quantity of the carbon dioxide introduced into the process water and a concentration of dissolved or dispersed carbon dioxide in the process water, as presently claimed, it has long been an axiom of United States patent law that it is not inventive to discover the optimum or workable ranges of result-effective variables by routine experimentation. In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003) ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Boesch, 617 F.2d 272, 276 (CCPA 1980) ("[D]iscovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art."); In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."). "Only if the 'results of optimizing a variable' are 'unexpectedly good' can a patent be obtained for the claimed critical range." In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (quoting In re Antonie, 559 F.2d 618, 620 (CCPA 1977)). At the time of the invention, it would have been obvious to one of ordinary skill in the art to vary the amounts of injecting time of the carbon dioxide into the mixture, which would necessarily vary the concentration of dispersed carbon dioxide in the mixture, including over the amounts presently claimed, in order to achieve desirable performance of the gypsum product, e.g., setting time, and/or strength, and thereby arrive at the claimed invention. Applicant further argues: “Rather, Parkhurst indicates that its method provides a product "of greater bulk per unit of calcined gypsum than has heretofore been obtainable" (Parkhurst at lines 30-32), which is a result of the "thick cream" (Parkhurst at line 73) produced in the process of Parkhurst. The "thick cream" results from CO2, which is not dissolved in the water, becoming entrapped in the gypsum slurry after mixing of the water and gypsum has already begun. Incorporating the CO2 into the water before the water is contacted with gypsum would compromise the formation of such "thick cream", which according to Parkhurst provides greater bulk per unit of calcined gypsum. Therefore, one of skill in the art would not have modified the teaching of Parkhurst, in view of Loechel or any other prior art references, to introduce a measured quantity of carbon dioxide at a concentration of at least 1 g/L and no more than 15 g/L into a process water prior to mixing with gypsum to reach the elements of amended independent claim 1.” Remarks, p. 7 The Examiner respectfully traverses as follows: Firstly, there is no evidence, i.e., data to support the position that “Incorporating the CO2 into the water before the water is contacted with gypsum would compromise the formation of such "thick cream", which according to Parkhurst provides greater bulk per unit of calcined gypsum.”. Secondly, Parkhurst teaches the amount of CO2 introduced is a result effective variable, specifically, Parkhurst teaches by mixing carbon dioxide with calcined gypsum (i.e., stucco) and water, the setting time of which is somewhat delayed; which will have adequate strength to permit handling and use immediately following removal from, the molds; which does not require any period of seasoning; which is of very much greater strength than prior gypsum products, and which is not so dependent upon accuracy of proportion of water and calcined gypsum (i.e., the introducing of carbon dioxide to the slurry is a result effective variable to various product performances of the gypsum product) (Parkhurst, page 2, left column, 3rd paragraph); injecting the carbon dioxide into the mixture for a period of not less than about three minutes (wherein the injecting time affects the amount of dissolved or dispersed carbon dioxide introduced into the mixture) (Parkhurst, Claim 5). Although there are no disclosures on the amounts of measured quantity of the carbon dioxide introduced into the process water and a concentration of dissolved or dispersed carbon dioxide in the process water, as presently claimed, it has long been an axiom of United States patent law that it is not inventive to discover the optimum or workable ranges of result-effective variables by routine experimentation. In re Peterson, 315 F.3d 1325, 1330 (Fed. Cir. 2003) ("The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages."); In re Boesch, 617 F.2d 272, 276 (CCPA 1980) ("[D]iscovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art."); In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."). "Only if the 'results of optimizing a variable' are 'unexpectedly good' can a patent be obtained for the claimed critical range." In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (quoting In re Antonie, 559 F.2d 618, 620 (CCPA 1977)). At the time of the invention, it would have been obvious to one of ordinary skill in the art to vary the amounts of injecting time of the carbon dioxide into the mixture, which would necessarily vary the concentration of dispersed carbon dioxide in the mixture, including over the amounts presently claimed, in order to achieve desirable performance of the gypsum product, e.g., setting time, and/or strength, and thereby arrive at the claimed invention. Applicant further argues: “Finally, amended independent claim 1 also recites "the stucco is mixed with the process water having the carbon dioxide introduced therein to provide a water/stucco weight ratio in a range of about 0.5 to 0.8." In contrast, Parkhurst discloses and claims "a mixture comprising the reaction products of one part of calcined gypsum with not less than one part of water ...". Claim 9 of Parkhurst (emphasis added); see also claims 10 and 13 of Parkhurst. Furthermore, Parkhurst discloses that "[i]n carrying out my process, I have obtained very satisfactory results by taking one volume of calcined gypsum ... and two volumes of water" and "[t]hese are placed in the container 10, shaft 13 is rotated, and carbon dioxide injected into the mixture during the period of rotation of the shaft 13." Parkhurst at lines 54-61 (emphasis added). The teaching in Parkhurst of using "not less than one part of water" to "one part of calcined gypsum" in the mixture would dissuade one of skill in the art from using an amount of water of 0.5 to 0.8 part to one part of stucco, as recited by amended independent claim 1 of the present application. Thus, even if one of skill in the art relied on Loechel for the alleged teaching of an amount of water of about 65 to about 120% of the weight of the gypsum stucco, one of skill in the art would not adjust the water content to less than 100% in view of the entire disclosure of Parkhurst. Parkhurst explicitly discloses that "I can produce a product, the setting time of which is somewhat delayed; in which a greater proportion of water may be used; which will 'set' in the presence of even a large excess of water .. ." Parkhurst at lines 21-26. That is, Parkhurst is directed to using more water in the mixture of calcined gypsum and water. In contrast, one of the aims of the method for producing a gypsum article of amended independent claim 1 is to reduce the water demand of the method (i.e., less CO2-containing water is needed to achieve the same flowability in the gypsum slurry than if water is used that does not contain CO2). This effect is demonstrated in the examples of the application. As Parkhurst only discloses a minimum volume ratio of 1.0 and indicates that the advantage of its method is to use more water, the method for producing a gypsum article of amended independent claim 1, in which the water/stucco ratio is about 0.5 to 0.8, is not obvious.” Remarks, p. 8 The Examiner respectfully traverses as follows: First, disclosed examples and preferred embodiments do not constitute a teaching away. Specifically, there is no disclosure in Parkhurst to criticize, discredit, or otherwise discourage from the claimed a water/stucco weight ratio in a range of about 0.5 to 0.8. Secondly, Parkhurst teaches that one application of mixing carbon dioxide with calcined gypsum and water, is that greater proportion of water may be used (emphasis added), amongst others including of greater bulk, greater strength (Parkhurst, page 1, left column, lines 25-35). Therefore, Parkhurst does not require a greater proportion of water to be used. Thirdly, Loechl provides a proper motivation to combine, i.e., depending upon the particular source of the gypsum rock and its processing, the water to be added may vary within the range, say, from about 65 to about 120% of the weight of gypsum stucco (pages 5-6 of Office Action mailed 09/17/2025). Therefore, it is the examiner' s position that it would be obvious to one of ordinary skill in the art to combine Parkhurst with Loechl, in order to produce a properly handeable slurry depending on particular source of the gypsum rock and its processing, absent evidence to contrary. Applicant further argues: “That is, the gypsum products produced by the method of Parkhurst are produced in a discrete quantity and within a discrete period of time until the method of Parkhurst is restarted. Furthermore, the process and processing equipment of Parkhurst are not adapted/configured to processing a gypsum slurry in a continuous process. That is, a continuous process could not be realized by one of skill in the art on the basis of the teachings of Parkhurst. In contrast, new claims 21 and 22 specify that the method produces the gypsum articles continuously. The other cited prior art of record do not cure the deficiencies of Parkhurst. Therefore, new claims 21 and 22 are neither anticipated by nor rendered obvious by the cited prior art of record.” Remarks, p. 9 The Examiner respectfully traverses as follows: Firstly, the phrase “continuously” recited in claim 21 is interpreted as continuous for any given period time, given that the specification only provides support for forming of the gypsum article into the desired shape in a continuous operation, such as a moving conveyor (specification, page 8, bottom paragraph), and the specification does not provide support for the entire process of producing the gypsum article, including introducing carbon dioxide with stucco in a continuous operation, instead of batch operation, as set forth above in item 4. Secondly, Parkhurst meets the present claim, including the phrase “continuously”, as set forth above on pages 13-16. Therefore, the Examiner has fully considered Applicant’s arguments, but they are found unpersuasive. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KELING ZHANG whose telephone number is (571)272-8043. The examiner can normally be reached Monday - Friday: 9:00am-5:00pm EST. 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, Ching-Yiu Fung can be reached at 571-270-5713. 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. /KELING ZHANG/ Primary Examiner Art Unit 1732
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Prosecution Timeline

May 20, 2021
Application Filed
May 20, 2021
Response after Non-Final Action
Aug 23, 2024
Non-Final Rejection — §103, §112
Nov 27, 2024
Response Filed
Mar 28, 2025
Final Rejection — §103, §112
Jul 07, 2025
Request for Continued Examination
Jul 08, 2025
Response after Non-Final Action
Sep 13, 2025
Non-Final Rejection — §103, §112
Dec 17, 2025
Response Filed
Feb 13, 2026
Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
67%
Grant Probability
86%
With Interview (+19.8%)
3y 5m
Median Time to Grant
High
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