DETAILED ACTION
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 § 103
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
In considering the obviousness rejections below, the applicant should note that the person having ordinary skill in the art at the time of the effective filing date of the claimed invention has the capability of understanding the scientific and engineering principles applicable to the claimed invention. The references of record in the application reasonably reflect this level of skill.
Claims 1-15 are rejected under AIA 35 U.S.C. 103 as being unpatentable over Tachi et al., US 2014/0371400 (2014) (see applicant’s 6/13/23 IDS) (“Tachi”) as illustrated by Dairoku et al., US 6,228,930 (2001) (“Dairoku”)1. Regarding claims 1 and 7, Tachi teaches a method comprising i) polymerizing an aq. solution that comprises partially neutralized2 acrylic acid (herein “AA”), NaOH, the crosslinking agent polyethylene glycol diacrylate (“PEGDA”), and an initiator (here, aq. sodium persulfate) (see Tachi at, e.g., par. 248-253), ii) drying the resulting polymer gel to obtain a dried polymer (see id. at, e.g., par. 256-57), iii) pulverizing the dried polymer to obtain polymer particles (see id.), iv) classifying/sieving the polymer particles, removing undersized particles (“UPs”) from desirably-sized particles (“DSPs”), and thermally surface-crosslinking the DSPs (see id. at, e.g., par. 256-57 and 262-64), v) mixing 200g of the UPs with 300g of water to form an agglomerated polymer gel (“APG”; see id. at, e.g., par. 258-59, citing Dairoku at, e.g., col. 24, ln. 61 to col. 25, ln. 16, col. 37, ln. 64 to col. 38, ln. 11, and Fig. 7), i.e. the APG is reasonably considered to have a moisture content of 60 wt% as claimed, and vi) recycling the APG into step ii), i.e. drying the APG. See Tachi at, e.g., par. 258-59, citing Dairoku at, e.g., col. 24, ln. 61 to col. 25, ln. 16, col. 37, ln. 64 to col. 38, ln. 19, and Fig. 7). Tachi’s drying step ii) employs static drying as claimed, i.e. Tachi’s hot-air-based drying is not said to involve fluidizing or otherwise agitating the polymer gel. While Tachi (as illustrated by Dairoku) does not specify that its step v) water comprises a crosslinker, it nevertheless would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to do so, given that (further) crosslinking the UPs will desirably increase their mechanical strength and thereby prevent or at least reduce the propensity of the APG formed in step v) to be broken into further UPs (“fUPs”) upon recycling the APG into step ii)’s drying and subsequently step iii)’s pulverizing of the resulting dried polymer; reducing the amount of fUPs formed will desirably reduce or eliminate the need for the further processing of the (f)UPs in subsequent iterations of steps v)-vi). MPEP 2143 I.(C)-(D) & (G). The so-employed crosslinker is reasonably considered to necessarily form covalent or ionic bonds with at least two carboxylate groups of the UPs, as this is the purpose of a crosslinker employed with carboxylate-comprising monomers and/or polymers thereof.
Regarding claim 2, the employing of a crosslinker-comprising aq. solution in step v) being prima facie obvious as detailed above, and given that selecting and/or altering the order of mixing prior art materials is a prima facie obvious design choice absent a showing of new or unexpected results or the criticality thereof, not found within the instant application (MPEP 2144.04 IV.C.), it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add crosslinker toward the end of the step v) water addition. In doing so, the portion of water added prior to the portion into which the crosslinker is added is considered to meet the claimed step of “first mix[ing] with water… and then mix[ing] with the aqueous solution” that comprises the crosslinker.
Regarding claims 3 and 5, Tachi’s step i) employs 2.75g of its 523g/mol-MW PEGDA (i.e. ~0.005 mol PEGDA) crosslinker with 421.7g of AA (i.e. ~5.85 mol AA), and 140.4g of 48.5 wt% aq. NaOH (i.e. ~68.09 g NaOH, i.e. ~1.70 mol NaOH), i.e. 2.75g crosslinker per 461.94g overall polymerization reagent mixture (492.54g total - [1.7molH2O x 18g/molH2O] = 461.94g).3 Thus, 2.75g / 461.94g = ~0.6 wt% crosslinker is present in Tachi’s step i). As such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to simply employ the same concentration of crosslinker when conducting step v) as well, given that employing such a crosslinker concentration was effective in Tachi’s step i). MPEP 2143 I.(C)-(D) & (G). In doing so, the PEGDA can/will form covalent bonds with ≥2 carboxylate groups of the UPs/APG polymer per claim 5.
Regarding claim 4, Tachi teaches that the amount of crosslinker employed in its step i) can be adjusted as desired, “depending on desired physical properties of the [resulting target] water absorbent resin[.]” See Tachi at, e.g., par. 142. Given the foregoing, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to ascertain and employ a desired crosslinker concentration for the crosslinking aspect of its step i), and thus that of step v)’s as well, such as within the claimed range, via routine experimentation- it has been held that “where 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.” See MPEP 2144.05, citing In re Aller, 220 F.2d 454, 456 (CCPA 1955). Additionally and/or alternatively, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ a reduced crosslinker concentration in step v) compared to that employed in step i), given that the UPs being converted to an APG have already undergone at least some crosslinking during step i) (and thus less crosslinker would be necessitated in step v) compared to that employed in step i) to achieve the desired effect, i.e. of forming a mechanically strengthened APG. As such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to ascertain and employ a desired amount/concentration of crosslinker in step v) to achieve the desired effect of mechanically strengthening the resulting APG, such as within the claimed range, via routine experimentation. MPEP 2144.05, citing In re Aller.
Regarding claim 6, Tachi teaches the effectiveness and interchangeability of such crosslinkers as PEGDA and (poly)ethylene glycol diglycidyl ether (“PEGDE”, which has two epoxy groups), rendering it prima facie obvious to employ PEGDE instead of PEGDA as its step i) (and thus step v)) crosslinker. MPEP 2144.06 & 2144.07.
Regarding claims 8-9, Tachi teaches that the amount of UPs (defined as <150 µm) formed (and removed in its step iv)) is preferably 0-30 wt%, with 5-25 wt% being especially preferred; 100% of the UPs removed are reasonably understood to be of <150 µm size, as they pass through Tachi’s 150 µm mesh-size sieve. See Tachi at, e.g., par. 189 and 257. Note: said claims’ “90% by weight” is construed to mean “at least 90% by weight” so as to not conflict with claim 1 (and thus be rejectable under 35 U.S.C. 112(d)/4th par. for contradicting its base claim, see MPEP 608.01(n)III), given claim 1’s step iv)’s “classifying” step, which is understood to involve employing a certain sieve size. Given the foregoing, it would not be reasonable to presume that up to 10 wt% (or any, for that matter) of Tachi’s UPs could/would pass through Tachi’s chosen 150 µm sieve size. See Tachi at, e.g., par. 189 and 257 (sieve size employed to separate/remove UPs).
Regarding claims 10-11, Tachi teaches that 20 wt% of its step iii) product polymer particles are sieved away as UPs in its step iv); this is the amount eventually (in step vi)) recycled (as APG) into step ii). See id. at, e.g., par. 257.
Regarding claim 12, Tachi’s step v) (as illustrated by Dairoku) has a 3 minute, 10 second dwell time. See Tachi at, e.g., par. 258-59; Dairoku at, e.g., col. 37, ln. 64 to col. 38, ln. 17.
Regarding claims 13-14, Tachi’s drying step ii) is performed at 180oC for 40 minutes. See Tachi at, e.g., par. 256-57.
Regarding claim 15, Tachi’s surface-crosslinked DSPs are “allowed to pass through a JIS standard sieve with a mesh size of 850 µm” (see id. at, e.g., par. 262-64); as no particles are said to be retained on said sieve, the amount of undersized surface-crosslinked DSPs is considered to be 0 wt%.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL BERNS whose telephone number is (469)295-9161. The examiner can normally be reached M-F 8:30-5:00 (Central). 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, Anthony Zimmer can be reached at (571) 270-3591. 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.
/DANIEL BERNS/ January 9, 2026
Primary Examiner
Art Unit 1736
1 Dairoku is not meant to be combined with Tachi, but rather is cited to illustrate the steps Tachi refers to in Dairoku (Tachi at par. 259, cited herein, performs steps “according to the method of… [Dairoku].”).
2 Tachi’s step i) employs 421.7g of AA (i.e. ~5.85 mol AA) with 140.4g of 48.5 wt% aq. NaOH (i.e. ~68.09 g NaOH, i.e. ~1.70 mol NaOH), i.e. ~29.1 mol% of the AA’s -COOH groups are neutralized (as -COONa).
3 1.7mol of water, i.e. 30.6g water, is lost/released when the 1.7 mol of NaOH reacts with the AA’s -COOH groups to form -COONa and water.