Prosecution Insights
Last updated: April 19, 2026
Application No. 17/997,164

THREE-DIMENSIONAL PRINTING OF HYDROGELS

Non-Final OA §103
Filed
Oct 26, 2022
Examiner
WANG, ALEXANDER A
Art Unit
1741
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Hewlett-Packard Development Company, L.P.
OA Round
3 (Non-Final)
65%
Grant Probability
Favorable
3-4
OA Rounds
3y 2m
To Grant
87%
With Interview

Examiner Intelligence

Grants 65% — above average
65%
Career Allow Rate
166 granted / 254 resolved
At TC average
Strong +22% interview lift
Without
With
+21.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
51 currently pending
Career history
305
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
54.7%
+14.7% vs TC avg
§102
16.4%
-23.6% vs TC avg
§112
23.7%
-16.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 254 resolved cases

Office Action

§103
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 . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/22/2025 has been entered. Response to Amendment Applicant amendment filed 12/22/2025 has been entered and is currently under consideration. Claims 1-2, 4-7, 9-12, and 16-22 remain pending in the application. 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. Claim(s) 1-2, 4-6, and 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bredt et al. (US2001/0050031) hereinafter Bredt in view of Knopf et al. (US202/0062877 of record) hereinafter Knopf. Regarding claim 1, Bredt teaches: A three-dimensional printing kit, comprising: a particulate build material consisting of a polyhydroxylated polymer having hydroxyl groups and selected from the group consisting of polyvinyl alcohol, poly(2-hydroxyethyl acrylate), poly(2- hydroxyethyl methacrylate), poly(acrylic acid), poly(methacrylic acid), and a combination thereof ([0015, 0068]); a crosslinking agent for crosslinking the polyhydroxylated polymer by a reaction with the hydroxyl groups of the polyhydroxylated polymer to form a hydrogel ([0025, 0079]; applicant specification discloses sodium tetraborate as a suitable crosslinking agent); Bredt does not teach a structural modifier separate from the particulate build material, the structural modifier having a plurality of functional groups that react to form a network within the hydrogel, wherein the structural modifier has a reactivity that is chemically orthogonal to the reaction of the hydroxyl groups of the polyhydroxylated polymer and the crosslinking agent for crosslinking the polyhydroxylated polymer to form the hydrogel. In the same field of endeavor regarding additive manufacturing, Knopf teaches a jettable composition comprising a structural modifier having a plurality of functional groups that react to form a network within the hydrogel, wherein the structural modifier has a reactivity that is chemically orthogonal to the reaction of the hydroxyl groups of the polyhydroxylated polymer and the crosslinking agent for crosslinking the polyhydroxylated polymer to form the hydrogel for the motivation of providing high toughness and excellent optical clarity ([0011, 0024, 0108-0113]). Bredt further teaches a binder material that is separate from the particulate build material and is dispensed into a powder bed with the particulate build material ([0007]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the binder as taught by Bredt to include a structural modifier as taught by Knopf in order to provide high toughness and excellent optical clarity. Regarding claim 2, Bredt in view of Knopf teaches the kit of claim 1. Bredt further teaches further teaches wherein the crosslinking agent is reactive to form (a) hydrogen bonds, (b) ester groups, or (c) a metal ion coordination complex with the hydroxyl groups of polyhydroxylated polymers ([0025, 0079]; applicant specification discloses sodium tetraborate as a suitable crosslinking agent). Knopf further teaches wherein the structural modifier is reactive to form the network by a thiol-ene reaction, Michael addition, a thiol-yne reaction, a 1,3-dipolar cycloaddition or a Diels-Alder reaction ([0108-0113]). Regarding claim 4, Bredt in view of Knopf teaches the kit of claim 1. Knopf further teaches a reaction promoter to initiate a reaction between the plurality of functional groups of the structural modifier ([0166]). Regarding claim 5, Bredt in view of Knopf teaches the kit of claim 1. Knopf further teaches wherein the structural modifier is a first structural modifier and the plurality of functional groups is a plurality of first functional groups, the three-dimensional printing kit further comprises a second structural modifier having a plurality of second functional groups, wherein the plurality of first functional groups of the first structural modifier react with the plurality of second functional groups of the second structural modifier to form the network within the hydrogel ([0103-0114]). Regarding claim 6, Bredt in view of Knopf teaches the kit of claim 5. Knopf further teaches wherein the plurality of first functional groups of the first structural modifier is a plurality of thiol groups ([0113]), and wherein the plurality of second functional groups of the second structural modifier is a plurality of alkene groups ([0108]). Regarding claim 16, Bredt in view of Knopf teaches the kit of claim 5. Knopf further teaches wherein the plurality of functional groups of the first structural modifier is two or more alkene groups ([0108]), and wherein the plurality of functional groups of the second structural modifier is three or more thiol groups ([0113]). Regarding claim 17, Bredt in view of Knopf teaches the kit of claim 5. Knopf further teaches wherein the first structural modifier is poly(ethylene glycol) diacrylate ([0108]) and the second structural modifier is pentaerythritol tetrakis(3-mercaptopropionate) ([0113]). Regarding claim 18, Bredt in view of Knopf teaches the kit of claim 1. Bredt further teaches wherein the crosslinking agent is selected from the group consisting of sodium tetraborate, potassium tetraborate, and lithium tetraborate ([0025, 0079]). Claim(s) 19-22, and 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bredt in view of Nielson et al. (US2004/0135276) and Knopf. Regarding claim 19, Bredt teaches: A three-dimensional printing kit, comprising: a particulate build material comprising a polyhydroxylated polymer having hydroxyl groups and selected from the group consisting of polyvinyl alcohol, poly(2- hydroxyethyl acrylate), poly(2-hydroxyethyl methacrylate), poly(acrylic acid), poly(methacrylic acid), and a combination thereof ([0015, 0068]); a crosslinking agent for crosslinking the polyhydroxylated polymer by a reaction with the hydroxyl groups of the polyhydroxylated polymer to form a hydrogel ([0025, 0079]; applicant specification discloses sodium tetraborate as a suitable crosslinking agent); a jettable agent including water ([0057-0058]). Bredt does not teach a first jettable agent including water and a first structural modifier; and a second jettable agent separate from the first jettable agent, the second jettable agent including water and a second structural modifier. In the same field of endeavor regarding additive manufacturing, Nielson teaches printing using separate jettable agents for the motivation of allowing printing of various colors ([0039]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the kit as taught by Bredt with the separate jettable agents as taught by Nielson in order to allow printing of various colors. Bredt does not teach wherein a first jettable agent including a first structural modifier; and a second jettable agent separate from the first jettable agent, the second jettable agent including a second structural modifier, and each of the first and second structural modifiers has a plurality of functional groups that react to form a network within the hydrogel and has a reactivity that is chemically orthogonal to the reaction of the hydroxyl groups of the polyhydroxylated polymer and the crosslinking agent for crosslinking the polyhydroxylated polymer to form the hydrogel. In the same field of endeavor regarding additive manufacturing, Knopf teaches a jettable composition comprising a structural modifier having a plurality of functional groups that react to form a network within the hydrogel, wherein the structural modifier has a reactivity that is chemically orthogonal to the reaction of the hydroxyl groups of the polyhydroxylated polymer and the crosslinking agent for crosslinking the polyhydroxylated polymer to form the hydrogel for the motivation of providing high toughness and excellent optical clarity ([0011, 0024, 0108-0113]). Bredt further teaches a binder material that is separate from the particulate build material and is dispensed into a powder bed with the particulate build material ([0007]). Nielson further teaches jetting separate binder material into a powder bed ([0021-0022, 0039]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the binders as taught by Bredt in view of Nielson to include a structural modifier as taught by Knopf in order to provide high toughness and excellent optical clarity. Regarding claim 20, Bredt in view of Nielson and Knopf teaches the kit of claim 19. Nielson further teaches the first and second jettable agents Bredt further teaches the jettable agent further includes a co-solvent ([0078]) and a surfactant ([0080]). Regarding claim 21, Bredt in view of Nielson and Knopf teaches the kit of claim 20. Knopf further teaches wherein at least one of the first and second jettable agents further includes a radical initiator ([086]). Regarding claim 22, Bredt in view of Nielson and Knopf teaches the kit of claim 19. Knopf further teaches wherein the first structural modifier has two or more alkene groups ([0108]) and the second structural modifier has two or more thiol groups ([0113]). Response to Arguments Applicant's arguments filed 12/22/2025 have been fully considered but they are not persuasive. Applicant arguments regarding Ookubo are moot in light of the new grounds of rejection. Applicant argues that Knopf does not appear to teach that the structural modifiers are separate from the monomer/oligomers. However, Bredt teaches that the polymer can be used in both the powder and binder material ([0024, 0068]). Knopf teaches that the curable formation can be used as a binder jetted into a powder bed. Therefore, the structural modifier of Knopf when used in the binder of Bredt would be separate from the polymer in the powder. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See 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). For at least the above reasons, the application is not in condition for allowance. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER A WANG whose telephone number is (571)272-5361. The examiner can normally be reached M-Th 8 am-4 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, Alison Hindenlang can be reached on 571-270-7001. 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. /ALEXANDER A WANG/Examiner, Art Unit 1741 /ALISON L HINDENLANG/Supervisory Patent Examiner, Art Unit 1741
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Prosecution Timeline

Oct 26, 2022
Application Filed
Mar 05, 2025
Non-Final Rejection — §103
Jun 12, 2025
Response Filed
Sep 16, 2025
Final Rejection — §103
Dec 22, 2025
Request for Continued Examination
Dec 27, 2025
Response after Non-Final Action
Jan 16, 2026
Non-Final Rejection — §103 (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
65%
Grant Probability
87%
With Interview (+21.5%)
3y 2m
Median Time to Grant
High
PTA Risk
Based on 254 resolved cases by this examiner. Grant probability derived from career allow rate.

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