Prosecution Insights
Last updated: April 19, 2026
Application No. 18/018,162

METHOD FOR PREPARING SUPER ABSORBENT POLYMER

Final Rejection §103§112
Filed
Jan 26, 2023
Examiner
RIOJA, MELISSA A
Art Unit
1764
Tech Center
1700 — Chemical & Materials Engineering
Assignee
LG Chem, Ltd.
OA Round
2 (Final)
50%
Grant Probability
Moderate
3-4
OA Rounds
3y 4m
To Grant
99%
With Interview

Examiner Intelligence

Grants 50% of resolved cases
50%
Career Allow Rate
421 granted / 847 resolved
-15.3% vs TC avg
Strong +55% interview lift
Without
With
+54.8%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
74 currently pending
Career history
921
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
42.2%
+2.2% vs TC avg
§102
14.2%
-25.8% vs TC avg
§112
31.2%
-8.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 847 resolved cases

Office Action

§103 §112
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 § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1 and 3 – 12 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Use of parentheses in Claim 1, i.e. (n=4 to 13), renders the claims indefinite as it is unclear whether the limitations enclosed in parentheses are required or optional features of the claim. Claims 3 – 12 are further rejected under this statute as they ultimately depend on Claim 1 and therefore inherit the aforementioned issue. For the purposes of further examination, the limitations enclosed in parentheses in Claim 1 will be interpreted as being required. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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. Claims 1, 3, 4, and 6 – 12 are rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0001122 to Wattebled et al. (hereinafter Wattebled) in view of WO 2004/037903 to Reimann et al. (hereinafter Reimann) and US 2017/0014801 to Ikeuchi et al. (hereinafter Ikeuchi). For the purposes of examination, citations for Reimann are taken from an English-language equivalent of the document, US 2006/0057389. Regarding Claims 1, 3, and 4. Wattebled teaches a method of preparing a superabsorbent polymer [0008]. The method comprising free-radically polymerizing an aqueous solution of an ethylenically unsaturated monomer having an acid group in the presence of a crosslinking agent to form a gel polymer [0038] – [0039], i.e. crosslinking polymerization of a water-soluble ethylenically unsaturated monomer in the presence of an internal crosslinking agent to form a water-containing gel polymer including a crosslinked polymer. The acid groups of the monomer may be partly or fully neutralized [0046]. The crosslinking polymerization further occurs in the presence of hollow bodies in which a hydrocarbon blowing agent is surrounded by a thermoplastic polymer material [0082] – [0084], i.e. a capsule-type foaming agent including a core including a hydrocarbon and a thermoplastic polymer shell surrounding said core. The method of Wattebled further comprising drying and grinding the polymers [0041] – [0042], which would be reasonably expected to form a base polymer powder. A surface crosslinking step may subsequently be performed [0069] – [0070]. Wattebled further teaches the ethylenically saturated monomers (α1) and (α2) are provided in amounts of preferably 70 to 98.79 weight percent and 0.1 to 44.89 weight percent respectively. The crosslinker is provided in an amount of preferably 0.01 to 2.5 weight percent [0055] – [0056]. The hollow bodies/capsule-type foaming agent are provided in an amount of most preferably 0.1 to 3 weight percent [0111]. Using these values, the preferred amount of crosslinker in Wattebled can be calculated to be in the range of roughly 0.01 to 3.6 weight percent, while the preferred amount of capsule-type foaming agent can be calculated to be preferably in the range of roughly 0.1 to 7.2 weight percent relative to the 100 parts by weight of the ethylenically unsaturated monomer. Wattebled does not expressly teach the internal crosslinking agent is epoxy-based. However, Reimann teaches the use of ethylene glycol diglycidyl ether as a crosslinking agent for ethylenically unsaturated monomers used in the preparation of absorbent polymers [0064]. The instant specification describes ethylene glycol diglycidyl ether as having an epoxy equivalent weight of 114 g/eq (see Footnote A1 of Table 1). Wattebled and Reimann are analogous art as they are from the same field of endeavor, namely methods of making absorbent polymers. Before the effective filing date of the instantly claimed invention, it would have been obvious to a person of ordinary skill in the art to provide ethylene glycol diglycidyl ether as the internal crosslinking agent in Wattebled. The motivation would have been that it has been held that it is obvious to select a known material based on its suitability for its intended use. See Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945); In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960); and MPEP 2144.07. In the instant case, Wattebled does teach the crosslinking agents disclosed by Reimann are suitably used in the disclosed method [0050] and Reimann expressly sets forth ethylene glycol diglycidyl ether as a crosslinking agent [0064]. Wattebled also does not expressly teach the crosslinking polymer is conducted in the presence of a chelating agent. However, Ikeuchi teaches the concept of adding a chelating agent during preparation of a water absorbing polymer, in an amount of up to 3 parts by weight of the solids content thereof [0319] – [0320]. Ikeuchi sets forth amino carboxylic acids as suitable chelating agents [0321] and uses diethylenetriamine pentaacetic acid in the inventive examples [0397]. Wattebled and Ikeuchi are analogous art as they are from the same field of endeavor, namely methods of making absorbent polymers. Before the effective filing date of the instantly claimed invention, it would have been obvious to a person of ordinary skill in the art to provide a chelating agent, e.g. an amino acid such as diethylenetriamine pentaacetic acid, in the amount taught by Ikeuchi during the crosslinking polymerization step of Wattebled. The motivation would have been that Ikeuchi teaches the addition of a chelating agent in this amount functions to prevent discoloration and improve the urine resistance of the articles in which it is incorporated [0319] – [0320]. Regarding Claims 6 and 7. Wattebled teaches the method of Claim 1 wherein the ethylenically saturated monomers (α1) and (α2) are provided in amounts of preferably 70 to 98.79 weight percent and 0.1 to 44.89 weight percent respectively. The crosslinkers may be provided in an amount of preferably 0.01 to 2.5 weight percent [0055] – [0056]. The crosslinking component may include polyethylene glycol di(meth)acrylates [0050], which will provide a branched polymer of poly(meth)acrylic acid including polyalkylene glycol in side chains. Regarding Claim 8. Wattebled teaches the method of Claim 1 wherein drying may be conducted at a temperature of 150°C for 2 hours ([0125] and [0127]). Regarding Claims 9 – 12. Wattebled teaches the method of Claim 1 but is silent with respect to the claimed properties. Consequently, the Office recognizes that all of the claimed effects or physical properties are not positively stated by the reference(s). However, Wattebled, when modified in the manner proposed, teaches a process employing all of the claimed steps and processing conditions, as well as the claimed ingredients in the claimed amounts. Therefore, the claimed effects and physical properties - i.e. a superabsorbent polymer having a gel strength, absorption rate, centrifuge retention capacity, and absorbency under pressure in the instantly claimed ranges - would implicitly be achieved by a process employing all of the claimed steps and processing conditions, as well as the claimed ingredients in the claimed amounts. See In Re Spada, 911, F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990) and MPEP 2111.01 (I)(II). If it is applicant’s position that this would not be the case: (1) evidence would need to be provided to support the applicant’s position and (2) it would be the Office’s position that the application contains inadequate disclosure as to how to obtain the claimed properties using only the claimed process employing the claimed steps, processing conditions, and ingredients in the claimed amounts. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over US 2012/0001122 to Wattebled et al. (hereinafter Wattebled) in view of WO 2004/037903 to Reimann et al. (hereinafter Reimann) and US 2017/0014801 to Ikeuchi et al. (hereinafter Ikeuchi) – as applied to Claim 1 above – and further in view of US 2022/0380617 to Fishman et al. (hereinafter Fishman). Regarding Claim 5. Wattebled teaches the method of Claim 1 wherein the capsule-type foaming agent used may be EXPANCEL® 920 DU 40 [0086]. Fishman provides evidence that the hydrocarbon contained in the core of EXPANCEL® 920 DU 40 is iso-pentane and the shell is a polymer formed from methacrylonitrile (Table 1). Response to Arguments Applicant's arguments filed October 29, 2025 have been fully considered but they are not persuasive. Applicant argues that the claims are not rendered obvious over the cited references at least because of the unexpectedly superior properties demonstrated in the present. It is applicant’s position that the data shown in Tables 1 and 2 of the present specification demonstrate the effectiveness of the specifically claimed combination of epoxy-based internal crosslinking agent, chelating agent, and a capsule-type foaming agent. Applicant notes that the none of the applied references teaches the concept of combining all three of these additives. Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support." In other words, the showing of unexpected results must be reviewed to see if the results occur over the entire claimed range. In re Clemens, 622 F.2d 1029, 1036, 206 USPQ 289, 296 (CCPA 1980) The Office respectfully submits that the proffered data is not commensurate in scope with the instant claims. For instance, the instantly claims set forth a method in which any chelating agent and any capsule-type foaming agent including a hydrocarbon-containing core surrounded by a thermoplastic resin shell are each provided in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the water-soluble ethylenically unsaturated monomer. On the other hand, the examples provided only utilize two species of chelating agents (EDTA-4Na and DTPA) in amounts of 0.1 to 0.5 parts by weight and two species of capsule-type foaming agent (F-36D and DTPA) in amounts of 0.1 to 3 parts by weight. This limited showing does not provide sufficient evidence to conclude that the alleged unexpected results would be achieved when any chelating agent is provided in any amount in the claimed range of 0.01 to 10 parts by weight per 100 parts by weight of the water-soluble ethylenically unsaturated monomer, as well as any capsule-type foaming agent having the claimed features in any amount in the claimed range of 0.01 to 10 parts by weight, as is instantly claimed. The outstanding rejection under 35 U.S.C. 103 has consequently been maintained. Conclusion THIS ACTION IS MADE FINAL. 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. Correspondence Any inquiry concerning this communication or earlier communications from the examiner should be directed to MELISSA RIOJA whose telephone number is (571)270-3305. The examiner can normally be reached Monday - Friday 10:00 am - 6:30 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, Arrie Lanee Reuther can be reached at (571)270-7026. 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. /MELISSA A RIOJA/Primary Examiner, Art Unit 1764
Read full office action

Prosecution Timeline

Jan 26, 2023
Application Filed
Jul 25, 2025
Non-Final Rejection — §103, §112
Oct 29, 2025
Response Filed
Feb 02, 2026
Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
50%
Grant Probability
99%
With Interview (+54.8%)
3y 4m
Median Time to Grant
Moderate
PTA Risk
Based on 847 resolved cases by this examiner. Grant probability derived from career allow rate.

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