DETAILED ACTION
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
The information disclosure statement (IDS) submitted on 02/19/2026 was filed after the mailing date of the non-final Office action on 08/29/2025. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS is being considered by the examiner.
Status of Previous Claim Rejections Under 35 USC § 112
The previous rejection of claims 1, 3, and 5-7 under 35 U.S.C. § 112(b) is withdrawn in view of the amendments to claim 1.
The previous rejection of claim 2 under 35 U.S.C. § 112(b) is moot in view of the canceled status of the claim.
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 US 2009/0263496 (A1) to Kijlstra et al. (“Kijlstra”).
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 exceeding 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, but is silent regarding the direct effect of the concentration of NaOH on the median diameter of the particles. However, such a phenomenon is well known in the art of particle manufacture.
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]. An example reducing agent is sodium hypophosphite (contains P). 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.
Nosaka does not teach the claimed concentration of NaOH. However, 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 (e.g., NaOH) concentration is a result-effective variable because it would directly affect the particle diameter, as disclosed by Okada above.
Kijlstra is directed to producing metal particle sols having a metal particle content. Abstract. The process involves the reaction of metal salt solution with hydroxide ions and a reducing agent. Para. [0016], [0041], [0046]. The pH may be as high as 12 and can be adjusted by base to establish a desired pH. Para. [0022], [0026]. The solution comprising hydroxide ions is obtainable from the reaction of bases, e.g., NaOH, and the concentration of hydroxides in the solution containing hydroxide ions may be within 0.001-2 mol/l, preferably 0.1-0.5 mol/L (para. [0044], [0045]), which overlaps the claimed range.
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, as taught by Okada and Kijlstra, because it 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 12/01/2025 have been fully considered, but they are not persuasive.
Applicant argues that Kijlstra is inapplicable to the present claims because Kijlstra obtains by a fundamentally different reaction compared to the present invention by precipitating and then reducing particles with a reducing agent.
In response, the argument is not persuasive because it does not take into account all references cited as a whole. With respect to Applicant's arguments against the Kijlstra individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See MPEP § 2145(IV), citing In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In the present instance, Nosaka discloses the presence and addition of NaOH (para. [0015], [0041]). Okada, directed to making metal powders (e.g., nickel) using reducing agent (e.g., sodium hypophosphite), expressly teaches that metal particle size can be controlled by adjusting pH, with NaOH being an example pH adjustor used in the fabrication of metal particles (para. [0040]-[0044], [0046]). Kijlstra is appropriately relevant and related art because it affirms the impact of hydroxide ions (e.g., originating from NaOH) on metal particle formation and provides a starting point for the skilled artisan to consider for the concentration of a pH adjusting component in a reducing environment.
Applicant argues that Kijlstra does not disclose that concentration of NaOH is used to influence particle diameter and that Kijlstra cannot be relied upon by the rejection to support a rejection based on routine optimization because Kijlstra does not recognize NaOH as influencing particle diameter.
In response, the argument does not take into account the teachings of Okada. Okada discloses that the particle size of metal powder can be controlled by adjusting pH as well as by adjusting the proportions of metal compound, dispersing agent, and reducing agent (para. [0046]). An example pH adjuster is sodium hydroxide (NaOH) (para. [0048]). Kijlstra discloses that particle size distribution, which is a parameter relevant to median diameter and particle size spread, is adjusted by controlling the precipitation step, which is in turn dependent on hydroxide ions (e.g., originating from NaOH) (para. [0015], [0021], [0044]). It is noted that Nosaka discloses a wide range of average particle size d50 ranging from as small as 0.1 µm to as large as 70 µm (para. [0014], [0027], [0028], [0030], [0031]). Given Okada’s and Kijlstra’s teachings regarding the impact of pH on particle size and distribution, a person of ordinary skill in the art would be motivated to tweak the concentration of the pH adjuster in Nosaka’s method to fine-tune the size and distribution of the metal particles produced.
Applicant argues that a skilled artisan could not have reasonably optimized Kijlstra to achieve the claimed subject matter when Kijlstra does not recognize a strong negative correlation between NaOH concentration and particle size.
In response, the argument is not commensurate in scope with the claimed invention. There is no claim requirement mandating a negative correlation between concentration of NaOH and median diameter of the metal particles. The claim recites an adjustment of NaOH concentration within the stated range to regulate the median diameter to any value of 10 µm or less. There is no particularity with respect to whether an increase or decrease of NaOH produces larger or smaller particles.
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.
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/VANESSA T. LUK/Primary Examiner, Art Unit 1733
March 07, 2026