DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. 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
2. A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 01 July 2026 has been entered.
Response to Amendments
3. Applicant’s election response dated 01 July 2026 has been entered into the record and is considered fully responsive. The applicant amended Claim 1 and Claim 5 and no new matter was added by the amendments. Claims 1, 2, 3, 4, 5, 6, 7, and 8 are currently pending and under examination. Claims 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18 were previously withdrawn due to an election.
Claim Rejections - 35 USC § 103
3. 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.
4. 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.
5. Claims 1, 2, 3 4, 5, 6, 7, and 8 are rejected under 35 U.S.C. 103 as being obvious over Wada et al. further in view of Kazufumi et al. and Riley et al.
Wada et al. (US Pub. No. 2008/0090719 A – previously presented) is directed toward a spongy sintered article of titanium (title). Kazufumi et al. (JP2017050185A – previously presented) is directed toward a gas diffusion layer for membrane electrode assemblies (title). Riley et al. (US3321413A) is directed toward activated azodicarbonamide blowing agent compositions (title).
Regarding Claim 1, Wada et al. discloses a composition for a porous transport layer (analogous to spongy sintered article useful in fuel cells on water electrolyzers in ¶2), the composition comprising:
(i) a titanium group element (powdered titanium in Ex. 4-6 in Table 1);
(ii) a solvent (water in Ex. 4-6 in Table 1);
(iii) a foaming agent (e.g.: neopentane in Ex. 4-6 in Table 1).
Pertaining to the new limitations of amended to Claim 1, Wada et al. does not contemplate the treatment of the foaming agent with a hydrophilic resin nor that the foaming agent is a solid material (since the surface treated).
Kazufumi et al. teaches the composition for forming a conductive porous layer (11) in ¶78 comprising a conductive carbon material, high molecular weight polymer (i.e.: a binder), a dispersant, a dispersion medium (i.e.: solvent) and a foaming agent. Since both Wada et al. and Kazufumi et al. are directed toward conductive porous layers useful for electrochemical process and are formed using a foaming agent, they are deemed analogous art. The conductive carbon material is analogous to the titanium element in the present application as both materials make the porous layer conductive. In ¶83, Kazufumi et al. discloses two preferred organic foaming agents (analogous to pyrolytic foaming agents of the instant application), which are azodicarbonamide (ADCA) and 4,4'-oxybisbenzenesulfonylhydrazide (OBSH). The foaming agents in Kazufumi et al. are defined to have an average particle size of 1 micron to 50 microns in ¶82. The advantage of having a well-defined particle size for the foaming agent ensure more predictable results as the particle size of the foaming agent will dictate the void size in the sintered conductive foam. It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the metallic foam forming composition of Wada et al. by using the organic foaming agents taught in Kazufumi et al. with the reasonable expectation of controlling the void size of the pores in the prepared titanium foam.
The combination of Wada et al. and Kazufumi et al. do not disclose the use of a hydrophilic resin to treat the surface of the solid foaming agent as required by amended Claim 1. Riley et al. is directed toward activated azodicarbonamide blowing agent compositions make it analogous art to Wada et al. and Kazufumi et al. since all three references are designed at making porous materials through the emission and release of gas during a heating. Like Kazufumi et al., Riley et al. discloses the use of azodicarbonamide (ADCA) as a foaming agent (abstract). Riley et al. further discloses the need to change or lower the decomposition temperature of ADCA (Col. 1 lines 69-72 to Col. 2 lines 1-6). Riley et al. indicates that the decomposition temperature of ADCA can be altered by the use of aliphatic hydroxylamine compounds (and metal salts) as per Col. 2 lines 49-59. In Col. 3 lines 1-20, Riley et al. indicates that the hydroxy amine compound can be poly(glycol) amines that are derived from an amine with chain extension occurring using ethylene oxide, propylene oxide, and/or epichlorohydrin. The resultant species can be rendered more hydrophilic by using a higher concentration of ethylene oxide over propylene oxide. The poly(glycol) amine is analogous to the hydrophilic resin of amended Claim 1 and the poly(glycol) amine would be attracted to the surface of a foaming agent (i.e.: ADCA) through hydrogen bonding interactions therefore treating the surface of the pore forming agent with a hydrophilic resin. It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the composition of Wada et al. and Kazufumi et al. with a poly(glycol) amine (i.e.: hydrophilic resin) as taught by Riley et al. with the reasonable expectation of being able to control the decomposition temperature of the green body that is heated to form the porous conductive material as the poly(glycol) amine facilitates control of the decomposition temperature of the foaming agent.
In the disclosure of the instant application in ¶29 (cited as US Pub No. 2024/0128470 A1), the following cascading ranges for the average diameter of the particle foaming agent are disclosed: 50 microns to 1 millimeter, 60 microns to 800 microns, and 80 microns to 250 microns. Moreover, the examples of the instant application only use AIBN having a single average particle size of 120 microns (¶59). Pertaining to the amendment to Claim 1, the applicant has restricted the particle size of the foaming agent to have an average diameter of 60 microns to 800 microns. The examiner finds that the above combination of references teaches a range (an average diameter in a range 1 micron to 50 microns) that approaches the lower end of the claimed range of Claim 1. Given that the examples in the instant application only use one particle sized material, the criticality of the lower limit of 60 microns for the claimed range has not sufficiently been established. It has been held that a prima facie case of obviousness exists when the claimed range does not overlap with the prior art but are merely close. See MPEP 2144.05(I).
The purpose of the granular particulate foaming agent is to direct the pore size of the pore within the porous transport layer. Particulate materials that foam upon decomposition influence pore size formation in two ways: as a space holder (Col. 3 Lines 68-75 and Col. 4 Lines 1-3 in Riley et al.) and by the generation of gas during decomposition (¶81-83 of Kazufumi et al.). Comparison of the space holder capability between the teachings of the prior art (e.g.: 50 micron particle size) vs. the claimed range (e.g.: 60 micron particle) results in a difference of ~20% assuming that the particle size of the foaming agent is roughly proportional with the resultant pore diameter in the sintered metallic sponge. Furthermore, the pore size is also directed by the rate of gas generation as indicated in ¶82 of Kazufumi et al. meaning the formation of nitrogen and carbon dioxide upon heating of an azodicarbonamide will lead to an increase in the size of the developing pore. The rate of gas generation will have a larger impact on the final size of the developing pore than the initial particle size of the granular foaming agent. Given the larger influence of the rate of gas generation, it would be obvious to one of ordinary skill in the art to expect the final pore size resulting from a 50 micron particulate foaming agent and 60 micro particulate foaming agents to be substantially similar.
Regarding Claim 2, Wada et al. in view of Kazufumi et al. and Riley et al. disclose the composition of Claim 1, where in the titanium group element is titanium (Ex. 4-6 in Table 1).
Regarding Claim 3, Wada et al. in view of Kazufumi et al. and Riley et al. disclose the composition of Claim 1, wherein the foaming agent is a pyrolytic chemical foaming agent as supported by the use of azodicarbonamide (ADCA) and 4,4'-oxybisbenzenesulfonylhydrazide (OBSH) (Kazufumi et al. in ¶82 and ¶83).
Regarding Claim 4, Wada et al. in view of Kazufumi et al. and Riley et al. disclose the composition of Claim 3, wherein the pyrolytic foaming agent comprises 4,4'-oxybisbenzene- sulfonylhydrazide (OBSH) as supported the preferred organic (pyrolytic) foaming agent (Kazufumi et al. in ¶83).
Regarding Claim 5, Wada et al. in view of Kazufumi et al. and Riley et al. disclose the composition of Claim 1, wherein the foaming agent is in a granular form.
Regarding Claim 6, Wada et al., discloses the composition of Claim 1 and the combination of reference further render the composition of Claim 6 obvious. The composition of Claim 6 requires the composition comprises 40 to 90 parts by weight of the titanium group element, 2 to 10 parts by weight of the solvent, and 5 to 40 parts by weight of the blowing agent (i.e.: foaming agent). In Ex. 4-6, Wada et al. explicitly discloses a concentration of 60 wt.% for the titanium powder. Wada et al., in particular, discloses the composition is applied to a substrate prior to foaming using a doctor blade (¶22) meaning that the viscosity of the slurry will dictate the thickness of the wet film and the thickness of the final film. Wada et al. evaluated different concentrations of blowing agent (i.e.: foaming agent) and water (solvent) with both of these species expected to modify the viscosity of the slurry. Moreover, Wada et al. teaches in the Table 1 (by Ex. 4-6) that the increased the concentration of the blowing agent will increase the porosity of the sintered titanium foam.
Given the effect of the concentrations of both the blowing agent and the solvent as taught by Wada et al. on the resultant sintered foam, it would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to optimize the levels of these two additives in the composition, including the levels of the claimed range, as part of routine experimentation. See MPEP 2144.05(II) – routine optimization
Regarding Claim 7, Wada et al., Kazufumi et al., and Riley et al. disclose the composition of Claim 1, further comprising a dispersant (surfactant such as alkylbenzene sulfonate in Ex. 4-6 in Table 1 in Wada et al.) and a binder (methylcellulose in Ex. 4-6 in Table 1 of Wada et al.).
Regarding Claim 8, Wada et al., Kazufumi et al., and Riley et al. render the composition of Claim 6 obvious as explained above; moreover, the composition of Claim 8 can also be derived from the combination of references. The limitations of Claim 8 require a composition of: 0.1 to 3.0 by weight of a dispersant; and 0.1 to 4 parts by weight of a binder with respect to 40 to 90 parts by weight of the titanium group element. In Ex. 4, 5, and 6 of Wada et al., there different composition are disclosed that comprise 60 wt.% titanium powder, 2.0-2.9 wt.% methylcellulose (i.e.: a binder), 0.4-3.0 wt.% blowing agent (i.e.: foaming agent), 4.0 wt.% alkylbenzene sulfonate (i.e.: surfactant), and other additives. Given the examples in the prior art (i.e.: Wada et al.), a prima facie case of obviousness exists as the concentrations of the titanium group (i.e.: titanium powder), the dispersant (i.e.: alkyl benzenesulfonate), and the binder (i.e.: methyl cellulose) overlap, approach, or are similar to the concentrations of the claimed range. See MPEP 2144.05(I).
Response to Arguments
6. Applicant’s arguments, see pg. 6-7, filed 01 July 2026 have been considered and are not persuasive. Regarding the amendment to Claim 1, the applicant has narrowed the range of the average diameter of the pore forming agent to 60 microns to 800 microns. The combination of Wada et al., Kazufumi et al., and Riley et al. disclose a range for the diameter of the pore forming agent from 1 micron to 50 microns. The upper limit of the prior art and the lower range of Claim 1 are substantially similar since they are about 10 microns different. When comparing two groups of particles with an average diameter of 50 microns to 60 microns, a large number of the particles between those two samples will have a similar particle size. Additionally, the generation of gas resulting from the decomposition of the foaming agent will further increase the size of the developing pores. This latter effect has a larger effect on the final size of the pore than the initial particle size of the granular foaming agent. Therefore, it seems unlikely to the examiner that the initial difference of 10 microns will have a significant impact on the resultant porosity of the annealed porous transport layer as further explained in greater detail above in the updated rejection of Claim 1.
In ¶29 of the instant application US Pub. No. 2024/0128470 A1, the following cascading ranges are disclosed for the average diameter of the particle that is the foaming agent: 50 microns to 1 mm, 60 microns to 800 microns, and 80 microns to 250 microns. Moreover, the applicant discloses the use of a pore forming agent having an average particle size of 120 microns in the examples. The applicant has further argued for the criticality of the average diameter of the particle being in the range of 60 microns to 800 microns. Given the aforementioned evidence, the applicant has not clearly rebutted the prima facie case against the range taught by Wada et al., Kazufumi et al., and Riley et al. In order to overcome the obviousness rejection, the applicant must provide clear evidence to support the criticality of the 60 microns to 800 microns average diameter for the foaming agent (i.e.: show data to support that the range in the prior art provides different or unexpected results than what is in the limitations of Claim 1). The applicant may consider amending the range for average diameter of the pore forming agent to be start at 120 microns as there are examples using this diameter and it is significantly different than the 1 micron to 50 microns taught by Wada et al., Kazufumi et al., and Riley et al.
7. The applicant has further argued on pg. 7 that the combination of references (i.e.: Wada et al., Kazufumi et al., and Riley et al.) fails to teach treating the pore forming agent with a hydrophilic resin. The examiner does not agree with this contention as the use of poly(glycol) amines (an example of a hydrophilic resin) would be attracted to the surface of a foaming agent (i.e.: ADCA) through hydrogen bonding interactions resulting in the apparent treatment of the surface of the pore forming agent with said hydrophilic resin.
8. In the examples of the instant application, the applicant has evaluated the effect of different compositions of the porous transport layer dispersion (i.e.: Table 1) on performance properties of the resultant PTL as illustrated in Table 2. It appears the applicant potentially has a stronger case for non-obviousness using different ratios of the components in the dispersion used to make the PTL. Even at very low levels of AIBN (i.e.: the foaming agent), the performance properties are significantly better than when no AIBN is present.
PNG
media_image1.png
411
793
media_image1.png
Greyscale
PNG
media_image2.png
366
771
media_image2.png
Greyscale
Conclusion
9. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN SYLVESTER whose telephone number is (703)756-5536. The examiner can normally be reached Mon - Fri 8:15 AM to 4:30 PM 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, James Lin can be reached at (571)272-8902. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
10. 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.
/KEVIN SYLVESTER/Examiner, Art Unit 1794
/JAMES LIN/Supervisory Patent Examiner, Art Unit 1794
Prosecution Insights