DETAILED ACTION
Continued Examination Under 37 CFR 1.114
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 05/11/2026 has been entered.
Status of Claims
Claims 1, 3, and 5-7 are pending and presented for examination on the merits.
Claim 1 is currently amended.
Information Disclosure Statement
One (1) information disclosure statement (IDS) was submitted on 06/22/2026. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS is being considered by the examiner.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3, and 5-7 are rejected under 35 U.S.C. 103 as being unpatentable over JP 2009-197317 (A) to Nosaka (“Nosaka”) (abstract and computer-generated translation are in file as of 08/29/2025) in view of US 2018/0015547 (A1) to Okada et al. (“Okada”) and Eluri et al., “Synthesis of nickel nanoparticles by hydrazine reduction: mechanistic study and continuous flow synthesis,” Journal of Nanoparticle Research, 2012, 14:800 (“Eluri”).
Regarding claim 1, Nosaka teaches a method of forming spherical NiP particles for use as conductive particles and having excellent monodispersibility (method for producing conductive metal particles). Abstract; para. [0001], [0010].
The method includes a step of mixing an aqueous solution of a nickel salt, a mixed solution of a pH adjuster and a pH buffer, and an aqueous solution of reducing agent containing phosphorus and a step of reducing and precipitating the mixture. Para. [0015].
In an example mixing sequence, an aqueous metal salt solution containing nickel is formed, followed by the formation of a pH-adjusted aqueous solution containing pH adjuster sodium hydroxide (NaOH). Para. [0041]. The aqueous metal salt solution and the pH-adjusted aqueous solution were then mixed (mixing a first aqueous solution containing Ni and NaOH). Para. [0041]. An aqueous reducing agent solution comprising sodium phosphinate is prepared (second aqueous solution containing P). Para. [0042]. Then, the metal salt-pH-adjusted solution mixture and the reducing agent solution are mixed (prepare third aqueous solution). Para. [0042].
The aqueous solution of nickel salt is adjusted so that the pH is alkaline and exceeds 7 when the mixture is mixed to initiate the reduction and precipitation and form Ni-based particles (third aqueous solution has a pH is greater than 7 and inducing a reductive deposition reaction in the third aqueous solution to produce Ni-based conductive metal materials). Para. [0015], [0039], [0043]-[0045].
The Ni-based particles have an average particle size d50 ranging from 0.1 to 70 µm (para. [0014], [0027], [0031]), which overlaps the claimed range. Where a smaller diameter is desired, the average particle size d50 ranges from 0.1 to 10 µm (para. [0014], [0028], [0030]), which falls within the claimed range.
Nosaka teaches adding sodium hydroxide to adjust the pH (para. [0041]), but is silent regarding how adjusting the concentration of NaOH affects the median diameter of the particles. Nosaka does not teach the NaOH as claimed.
Okada is directed to a method of making metal powder by a liquid-phase reduction method. Abstract; para. [0040]-[0042]. An example metal includes nickel. Para. [0043]. Example reducing agents are sodium hypophosphite (contains P) and hydrazine. Para. [0044].
Okada teaches that the particle size of the metal powder can be controlled by adjusting the mixing proportions of the metal compound, dispersing agent, and reducing agent and by adjusting the pH in the reduction step. Para. [0046]. The pH is preferably adjusted to 7 or more and 13 or less, and an example pH adjuster is sodium hydroxide (NaOH). Para. [0048]. By adjusting the proportions of metal compound, dispersing agent, and reducing agent, the proportions of other components in solution, e.g., pH adjuster, would also be adjusted. It therefore follows that the mean diameter of metal particles is implicitly regulated by adjusting the concentration of pH adjuster in aqueous solution.
The relationship between particle size and NaOH concentration is further discussed by Eluri. Eluri studies the effect of temperature and NaOH concentration on nickel particle size in a solution reduction environment. Abstract. Increasing the NaOH concentration corresponds to a decrease in the free energy of reaction, which in turn leads to a more spontaneous reaction, creating a higher number of nuclei and smaller particles (negative correlation where an increase in concentration of NaOH results in a decrease in median diameter of metal particles). Page 6 of 14 – right column; page 7 of 14. Lower concentrations of NaOH (0.1 M) produce fewer nickel particles (and therefore larger particles) compared to higher concentrations of NaOH (0.5 M). Abstract; page 8 of 14 – left column.
It is well held that discovering an optimum value of a result-effective variable involves only routine skill in the art. See MPEP § 2144.05(II). In the present instance, the pH adjuster (NaOH) concentration in Nosaka is a result-effective variable because it would directly affect the particle diameter, as disclosed by Okada and Eluri above. It would have been obvious to one of ordinary skill in the art to have varied the concentration of the sodium hydroxide pH adjuster of Nosaka, such as by adjusting the NaOH concentration to a value between 0.1 M and 0.5 M (0.100 mol/L to 0.500 mol/L), as taught by Okada and Eluri, because NaOH concentration has a direct impact on particle size and permits the user to customize for a specific particle size needed for a particular application.
Regarding claim 3, Nosaka teaches a particle size distribution (d90-d10)/d50 (dispersion) is 0.8 or less (para. [0014], [0032]), which falls within the claimed range.
Regarding claim 5, Nosaka teaches that the aqueous salt solution (first aqueous solution) may contain Cu. Para. [0012], [0015], [0025], [0041].
Regarding claim 6, Nosaka teaches that the aqueous salt solution (first aqueous solution) may contain Sn. Para. [0013], [0026], [0050].
Regarding claim 7, Nosaka teaches that the aqueous salt solution (first aqueous solution) may contain Cu. Para. [0012], [0015], [0025], [0041]. Broadly, Sn can be present in an amount of 0.05-10% by mass (para. [0013]), and Cu can be present in an amount of 0.01-18% by mass (para. [0012]). In an example, Sn and Cu can both be present in amounts of 0.67% by mass and 3.960% by mass, respectively. Para. [0051]; Table 1 – No. 5. The calculated molar ratio (Sn/Cu) is 0.0906, which falls within the claimed range.
Response to Arguments
Applicant's arguments filed 05/11/2026 have been fully considered.
Applicant argues that the claimed negative correlation between NaOH concentration and particle diameter for achieving a median diameter of 10 µm or less is not a well-known phenomenon.
In response, Eluri demonstrates that higher concentrations of NaOH enhance spontaneity in a reduction reaction that produces nickel particles. A more spontaneous reaction forms a higher number of nuclei, thereby leading to smaller particles. When lower concentrations of NaOH were tested, fewer nickel particles are produced (abstract; p. 6 of 14 – right column; p. 7 of 14; p. 8 of 14 – left column). It therefore follows that larger particles are produced at lower concentrations of NaOH. This aligns with the limitation claiming a negative correlation between particle size and NaOH concentration.
Applicant’s arguments with respect to Kijlstra (US 2009/0263496 (A1)) have been considered but are moot because the new ground of rejection does not rely on Kijlstra to address the claims.
Pertinent Prior Art
The following prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
KR 10-1324527 (B1) to Ahn et al. (computer-generated translation is attached) discloses an apparatus for making nickel powder by mixing nickel precursor with reducing agent and NaOH. Abstract. The average particle size of the synthesized nickel powders decreases as the concentration of NaOH increases. Para. [0069].
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to VANESSA T. LUK whose telephone number is (571)270-3587. The examiner can normally be reached Monday-Friday 9:30 AM - 4:30 PM ET.
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/VANESSA T. LUK/Primary Examiner, Art Unit 1733
September 30, 2026
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