Prosecution Insights
Last updated: April 19, 2026
Application No. 17/138,073

CORROSION CONTROL OF STAINLESS STEELS IN WATER SYSTEMS USING TIN CORROSION INHIBITOR WITH A HYDROXYCARBOXYLIC ACID

Non-Final OA §103
Filed
Dec 30, 2020
Examiner
GOLOBOY, JAMES C
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Chemtreat Inc.
OA Round
5 (Non-Final)
63%
Grant Probability
Moderate
5-6
OA Rounds
3y 2m
To Grant
72%
With Interview

Examiner Intelligence

Grants 63% of resolved cases
63%
Career Allow Rate
846 granted / 1335 resolved
-1.6% vs TC avg
Moderate +8% lift
Without
With
+8.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
72 currently pending
Career history
1407
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
53.5%
+13.5% vs TC avg
§102
15.7%
-24.3% vs TC avg
§112
20.0%
-20.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1335 resolved cases

Office Action

§103
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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114 was filed in this application after a decision by the Patent Trial and Appeal Board, but before the filing of a Notice of Appeal to the Court of Appeals for the Federal Circuit or the commencement of a civil action. Since this application is eligible for continued examination under 37 CFR 1.114 and the fee set forth in 37 CFR 1.17(e) has been timely paid, the appeal has been withdrawn pursuant to 37 CFR 1.114 and prosecution in this application has been reopened pursuant to 37 CFR 1.114. Applicant’s submission filed on 11/4/25 has been entered. Claim Rejections - 35 USC § 103 Claims 1, 3-14, 16-17, 19, and 21-23 are rejected under 35 U.S.C. 103 as being unpatentable over Kalakodimi (U.S. Pat. No. 10,174,429, “Kalakodimi ‘429”) in view of Lipinski (U.S. Pat. No. 4,913,823) and Ito (JP 2012-041606 A) In column 2 lines 7-33 Kalakodimi ‘429 discloses a method of suppressing corrosion of a corrodible metal surface that contacts a water stream in a water system, comprising introducing into the water stream a treatment composition including a tin(II) corrosion inhibitor and a hydroxycarboxylic acid promoter, as recited in claim 1. In column 5 lines 17-30 Kalakodimi ‘429 discloses that the tin(II) corrosion inhibitor is present in the water stream in an amount of 0.01 to 3 ppm and the hydroxycarboxylic acid promotor is present in an amount of 0.1 to 40 ppm, leading to a total concentration of 0.11 to 43 ppm, within the range recited in claim 1. From column 1 line 65 through column 2 line 6, column 4 lines 7-16, and in the reference’s claim 8, Kalakodimi ‘429 discloses that the treatment composition is provided in sufficient amount and for sufficient time to form a stable protective tin film on at least a portion of the corrodible steel surface, as recited in claim 1. In column 8 lines 30-33 Kalakodimi ‘429 discloses that the treatment composition can be applied to the water stream while the water system is on-line, indicating that a step of contacting the corrodible metal surface can be performed prior to introducing the treatment composition into the water stream, as recited in claim 1. As discussed above, Kalakodimi ‘429 discloses that the treatment composition is present in an amount of 0.11 to 43 ppm, encompassing the range recited in amended claim 1 as well as claims 3-4. Kalakodimi ‘429 discloses in column 2 lines 13-14 that the concentration of tin in the water stream can range from 0.01 to 3 ppm, as recited in claim 5, and encompassing the ranges recited in claims 6-7. As discussed above, Kalakodimi ‘429 discloses a promoted concentration of 0.1 to 40 ppm, as recited in claim 8 and encompassing the ranges recited in claims 9-10. In column 5 lines 24-26 Kalakodimi ‘429 further discloses narrower concentration ranges for the promoter meeting the limitations of claims 9-10. In column 5 lines 1-10 Kalakodimi ‘429 discloses that the promoter can be various acids recited in claim 11, and meeting the limitations of claim 21. In column 4 lines 56-61 Kalakodimi ‘429 discloses that the tin can be provided by various compounds recited in claim 12. In column 7 lines 29-38 Kalakodimi ‘429 discloses that the treatment composition can comprise a reducing agent, as recited in claim 13. In column 2 lines 44-50 Kalakodimi ‘429 discloses that that the water systems can be the types recited in claim 14. Introducing the treatment composition into the water stream while the water system is on-line, as discussed above, meets the limitations of claim 16. In column 5 lines 11-17 Kalakodimi ‘429 discloses that the ratio of corrosion inhibitor to promoter matches or falls within the range recited in claim 17. The differences between Kalakodimi ‘429 and the currently presented claims are: i) Kalakodimi ‘429 discloses in column 4 lines 31-34 and the reference’s claim 7 that the corrodible metal surface can be a steel, but does not specifically disclose stainless steel, and does not disclose the skin temperature of the stainless steel. Kalakodimi ‘429 does disclose that the water system can be a cooling tower. ii) Kalakodimi ‘429 discloses in the examples that the treatment composition provides protection against corrosion from chloride-containing water (see the table in column 8), but does not disclose water containing chloride in the specific amounts recited in claims 1 and 19. Kalakodimi ‘429 also does not specifically disclose the use of the treatment composition in water containing sulfates, as in newly added claim 23. iii) Some of the ranges of Kalakodimi ‘429 and Ito overlap or encompass the claimed ranges rather than falling within them. With respect to i), Lipinski discloses in column 7 lines 1-12 “simulated cooling tower units” containing a stainless steel heating coil having a skin temperature of 145° F, within the range recited in 1 and 19 and meeting the limitations of the claimed stainless steel. It would have been obvious to one of ordinary skill in the art to perform the method of Kalakodimi ‘429 in a system where the metal surface is a stainless steel surface having the skin temperature taught by Lipinski, since Lipinski indicates that they are representative of components present and contacted by water in a cooling tower. With respect to ii), an English-language machine translation of Ito, which is attached, has been used in setting forth this rejection, and the paragraph numbers referred to herein are those of the machine translation. In paragraph 1 Ito discloses an aqueous liquid composition for preventing corrosion and scale, and in paragraphs 57-58, 76, and 80-81 discloses that the composition is used in a water system such as a cooling tower (paragraphs 76, 81, and Figure 1). In paragraph 56 Ito discloses that the water to be treated has a chloride content of 0 to 3000 mg/L, which equates to 0 to 3000 ppm (1L water = 1000000 mg), overlapping the ranges recited in amended claim 1 and newly added claim 22, and further teaches that the water can comprise up to 3000 mg/L of sulfates, meeting the limitations of newly added claim 23. It would have been obvious to one of ordinary skill in the art to perform the method of Kalakodimi ‘429 with water having the chloride content taught by Ito, since Ito teaches that it is a suitable chloride content for application of corrosion inhibiting agents in water systems such as cooling towers. It is noted that the corrosion inhibitors taught in paragraph 17 of Ito can also be included in the composition of Kalakodimi ‘429 (column 7 lines 36, 42, 52-53, 59-61), and that Kalakodimi ‘429 also discloses in column 3 lines 7-15 that the tin-based (stannous) inhibitors have advantages over the zinc-based inhibitors of Ito; one of ordinary skill in the art would therefore understand that the tin-based inhibitor system of Kalakodimi ‘429 would also be effective in water systems having the chloride content taught by Ito. With respect to iii), See MPEP 2144.05(I): “In the case where the claimed ranges “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 light of the above, claims 1, 3-14, 16-17, 19, and 21-23 are rendered obvious by Kalakodimi ‘429 in view of Lipinski and Ito. Claims 1, 3-14, 16-17, and 19-23 are rejected under 35 U.S.C. 103 as being unpatentable over Kalakodimi (U.S. Pat. No. 10,174,429, “Kalakodimi ‘429”) in view of Ono (JP 10-214727) and Ito. In column 2 lines 7-33 Kalakodimi ‘429 discloses a method of suppressing corrosion of a corrodible metal surface that contacts a water stream in a water system, comprising introducing into the water stream a treatment composition including a tin(II) corrosion inhibitor and a hydroxycarboxylic acid promoter, as recited in claim 1. In column 5 lines 17-30 Kalakodimi ‘429 discloses that the tin(II) corrosion inhibitor is present in the water stream in an amount of 0.01 to 3 ppm and the hydroxycarboxylic acid promotor is present in an amount of 0.1 to 40 ppm, leading to a total concentration of 0.11 to 43 ppm, encompassing the range recited in amended claim 1 as well as claims 3-4. From column 1 line 65 through column 2 line 6, column 4 lines 7-16, and in the reference’s claim 8, Kalakodimi ‘429 discloses that the treatment composition is provided in sufficient amount and for sufficient time to form a stable protective tin film on at least a portion of the corrodible steel surface, as recited in claim 1. In column 8 lines 30-33 Kalakodimi ‘429 discloses that the treatment composition can be applied to the water stream while the water system is on-line, indicating that a step of contacting the corrodible metal surface can be performed prior to introducing the treatment composition into the water stream, as recited in claim 1. As discussed above, Kalakodimi ‘429 discloses that the treatment composition is present in an amount of 0.11 to 43 ppm, overlapping the range recited in claim 2 and encompassing the range recited in claims 3-4. Kalakodimi ‘429 discloses in column 2 lines 13-14 that the concentration of tin in the water stream can range from 0.01 to 3 ppm, as recited in claim 5, and encompassing the ranges recited in claims 6-7. As discussed above, Kalakodimi ‘429 discloses a promoted concentration of 0.1 to 40 ppm, as recited in claim 8 and encompassing the ranges recited in claims 9-10. In column 5 lines 24-26 Kalakodimi ‘429 further discloses narrower concentration ranges for the promoter meeting the limitations of claims 9-10. In column 5 lines 1-10 Kalakodimi ‘429 discloses that the promoter can be various acids recited in claim 11, and meeting the limitations of claim 21. In column 4 lines 56-61 Kalakodimi ‘429 discloses that the tin can be provided by various compounds recited in claim 12. In column 7 lines 29-38 Kalakodimi ‘429 discloses that the treatment composition can comprise a reducing agent, as recited in claim 13. In column 2 lines 44-50 Kalakodimi ‘429 discloses that that the water systems can be the types recited in claim 14. Introducing the treatment composition into the water stream while the water system is on-line, as discussed above, meets the limitations of claim 16. In column 5 lines 11-17 Kalakodimi ‘429 discloses that the ratio of corrosion inhibitor to promoter matches or falls within the range recited in claim 17. The differences between Kalakodimi ‘429 and the currently presented claims are: i) Kalakodimi ‘429 discloses in column 4 lines 31-34 and the reference’s claim 7 that the corrodible metal surface can be a steel, but does not specifically disclose stainless steel, and does not disclose the skin temperature of the stainless steel. Kalakodimi ‘429 does disclose that the water system can be a cooling tower. ii) Kalakodimi ‘429 discloses in the examples that the treatment composition provides protection against corrosion from chloride-containing water (see the table in column 8), but does not disclose water containing chloride in the specific amounts recited in claims 1 and 22. Kalakodimi ‘429 also does not specifically disclose the use of the treatment composition in water containing sulfates, as in newly added claim 23. iii) Some of the ranges of Kalakodimi ‘429 and Ito overlap or encompass the claimed ranges rather than falling within them. With respect to i), a machine translation of Ono, which is attached, has been used in setting forth this rejection, and the paragraph numbers referred to herein are those of the translation. In paragraphs 9 and 11-13 Ono disclose a cooling tower outlet pipe made of type 304 stainless steel (SUS304), meeting the limitations of the stainless steel of claims 1 and 20, where the water temperature is 140° F (60° C) or less, which will lead to a skin temperature in the same range during operation, overlapping the ranges recited in claims 1 and 19. It would have been obvious to one of ordinary skill in the art to use a pipe made of type 304 stainless steel in the cooling tower of Kalakodimi ’429, where the stainless steel has a skin temperature of 140° F or less, since Ono teaches that it is a suitable combination of material and temperature for use in a cooling tower, and because Ono teaches that the use of water having temperature of 140° F or less (leading to the corresponding skin temperature) helps reduce corrosion of the type 304 stainless steel. With respect to ii), an English-language machine translation of Ito, which is attached, has been used in setting forth this rejection, and the paragraph numbers referred to herein are those of the machine translation. In paragraph 1 Ito discloses an aqueous liquid composition for preventing corrosion and scale, and in paragraphs 57-58, 76, and 80-81 discloses that the composition is used in a water system such as a cooling tower (paragraphs 76, 81, and Figure 1). In paragraph 56 Ito discloses that the water to be treated has a chloride content of 0 to 3000 mg/L, which equates to 0 to 3000 ppm (1L water = 1000000 mg), overlapping the ranges recited in amended claim 1 and newly added claim 22, and further teaches that the water can comprise up to 3000 mg/L of sulfates, meeting the limitations of newly added claim 23. It would have been obvious to one of ordinary skill in the art to perform the method of Kalakodimi ‘429 with water having the chloride content taught by Ito, since Ito teaches that it is a suitable chloride content for application of corrosion inhibiting agents in water systems such as cooling towers. It is noted that the corrosion inhibitors taught in paragraph 17 of Ito can also be included in the composition of Kalakodimi ‘429 (column 7 lines 36, 42, 52-53, 59-61), and that Kalakodimi ‘429 also discloses in column 3 lines 7-15 that the tin-based (stannous) inhibitors have advantages over the zinc-based inhibitors of Ito; one of ordinary skill in the art would therefore understand that the tin-based inhibitor system of Kalakodimi ‘429 would also be effective in water systems having the chloride content taught by Ito. With respect to iii), See MPEP 2144.05(I): “In the case where the claimed ranges “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 light of the above, claims 1, 3-14, 16-17, and 19-23 are rendered obvious by Kalakodimi ‘429 in view of Ono and Ito. Response to Arguments Applicant's arguments filed 11/4/25 have been fully considered but they are not persuasive. Applicant argues that the amended claims require the water stream to include chloride in a range outside the range disclosed by the Kalakodimi ‘005 reference cited in previous office actions. However, the newly cited Ito reference teaches chloride contents of up to 3000 ppm, overlapping the ranges recited in the amended claims. As discussed in the rejection, one of ordinary skill in the art would have motivation to perform the method of Kalakodimi ‘429 in water streams having the chloride content of up to 3000 ppm disclosed by Ito, because Ito teaches that water streams having such a chloride content can be treated with corrosion inhibitors in order to reduce corrosion and scale formation, and Kalakodimi ‘429 teaches both that the tin-based inhibitor compositions have advantages over zinc-based compositions, and that the corrosion inhibitor components of Ito can also be included in the inhibitor composition of Kalakodimi ‘429. One of ordinary skill in the art would therefore conclude that the tin-based inhibitor compositions of Kalakodimi ‘429 would also be effective in water systems having a chloride content of up to 3000 ppm. Applicant has not provided any evidence demonstrating the criticality of the claimed chloride content, and in fact the data provided by applicant in the current specification uses water having chloride contents of 750 and 1000 ppm, outside the currently claimed ranges. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAMES C GOLOBOY whose telephone number is (571)272-2476. The examiner can normally be reached M-F, usually about 10:00-6:30. 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, PREM SINGH can be reached at 571-272-6381. 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. /JAMES C GOLOBOY/Primary Examiner, Art Unit 1771
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Prosecution Timeline

Dec 30, 2020
Application Filed
Jul 20, 2022
Non-Final Rejection — §103
Oct 26, 2022
Response Filed
Nov 07, 2022
Final Rejection — §103
Feb 13, 2023
Response after Non-Final Action
Mar 01, 2023
Response after Non-Final Action
Mar 01, 2023
Applicant Interview (Telephonic)
Mar 14, 2023
Request for Continued Examination
Mar 16, 2023
Response after Non-Final Action
Mar 20, 2023
Non-Final Rejection — §103
Jun 14, 2023
Examiner Interview Summary
Jun 14, 2023
Applicant Interview (Telephonic)
Jun 26, 2023
Response Filed
Jul 17, 2023
Final Rejection — §103
Sep 26, 2023
Notice of Allowance
Nov 27, 2023
Response after Non-Final Action
Nov 27, 2023
Response after Non-Final Action
Dec 05, 2023
Response after Non-Final Action
Dec 11, 2023
Response after Non-Final Action
Dec 21, 2023
Response after Non-Final Action
Apr 16, 2024
Response after Non-Final Action
Jun 13, 2024
Response after Non-Final Action
Aug 20, 2024
Response after Non-Final Action
Aug 20, 2024
Response after Non-Final Action
Aug 21, 2024
Response after Non-Final Action
Aug 21, 2024
Response after Non-Final Action
Sep 04, 2025
Response after Non-Final Action
Nov 04, 2025
Request for Continued Examination
Nov 05, 2025
Response after Non-Final Action
Jan 05, 2026
Non-Final Rejection — §103
Apr 10, 2026
Examiner Interview Summary

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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
63%
Grant Probability
72%
With Interview (+8.5%)
3y 2m
Median Time to Grant
High
PTA Risk
Based on 1335 resolved cases by this examiner. Grant probability derived from career allow rate.

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