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 .
This office action is in response to the amendment filed 10/24/2025. Claim 1 is amended; and claims 10-19 are withdrawn from consideration as being drawn to non-elected invention. Accordingly, claims 1-19 are currently pending in the application.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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.
The factual inquiries 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.
Claims 1 and 4-9 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu et al (US 2014/0348887 A1) in view of Leikhim et al (US 4,284,532) and Pich et al (US 2016/0168955 A1).
Regarding claim 1, Hsu et al disclose a stable aqueous composition containing a crosslinked, non-ionic amphiphilic polymer capable of forming a yield stress fluid in the presence of a surfactant (abstract). See example 33 (paragraphs 0169, 0211, and Table 8), wherein the polymer (i.e., reads on the polymer in present claim 1) is formed from monomers BEM (i.e., ethoxylated behenyl methacrylate and reads on the hydrophobic monomer in present claim 1) and AMPS (i.e., 2-acrylamido-2-methylpropane sulfonic acid and reads on the hydrophilic monomer in present claim 1).
Hsu et al are silent with respect to glycol ether; polymer prepared by RAFT micellar polymerization in the presence of glycol ether; powder composition; and properties.
However, regarding glycol ether, Hsu et al teach that yield stress fluid comprises at least one crosslinked nonionic amphiphilic polymer and an optional nonionic surfactant (paragraph 0121). Examples of nonionic surfactants are described in US Patent 4,284,532 (Leikhim et al) and incorporated herein in its entirety (paragraph 0147). Nonionic surfactants, in Leikhim et al, have the formula R(C2H4O)nOH wherein R is aliphatic hydrocarbyl radical containing from about 8 to about 18 carbon atoms, and n = about 3 to about 12 (col. 1, lines 55-68). Therefore, in light of the teachings in Leikhim et al and general disclosure of Hsu et al, it would have been obvious to one skilled in art prior to the filing of present application to include any of the nonionic surfactants including that taught in Leikhim et al, in the composition, of Hsu et al, absent evidence to the contrary.
Regarding polymer prepared by RAFT micellar polymerization in the presence of glycol ether, claims are written in a product-by-process form. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” See In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985).
Regarding powder composition, Pich et al in the same field of endeavor teach powder polymer for use in hydraulic fracturing (abstract). For ease of handling, emulsions have been used for several years but have the following disadvantages such as cost practically doubled with respect to powder polymers (paragraphs 0007-0009). Therefore, in light of the teachings in Pich et al, it would have been obvious to one skilled in art prior to the filing of present application, to prepare the composition, of Hsu et al in view of Leikhim et al, in the form of a powder, for above mentioned advantages.
Regarding properties, Hsu et al teach that amphiphilic polymers can be activated by a surfactant to provide a suitable yield stress fluid with the ability to suspend particles and insoluble materials in an aqueous medium for indefinite periods of time (paragraph 0120) and include crosslinked nonionic amphiphilic polymer (paragraph 0121). The amount of amphiphilic polymer utilized in forming the yield stress fluid is about 0.5 to about 5% by weight based on weight of the total composition (paragraph 0127). Therefore, given that the polymer is crosslinked, can be present in low amounts of about 0.5 wt% in preparing the yield stress fluid, and the activation of the crosslinked amphiphilic polymer with surfactant provides a suitable fluid with the ability to suspend particles and insoluble materials in an aqueous medium for indefinite periods of time, one skilled in art prior to the filing of present application would have a reasonable basis to expect the polymer, of Hsu et al in view of Leikhim et al and Pich et al, to form a three-dimensional interconnected network of bodies after hydration at a low shear ranging from 1500 rpm to less than 3,000 rpm when polymer is used in small amounts based on the weight of total composition, absent evidence to the contrary. Since PTO cannot conduct experiments, the burden of proof is shifted to the applicants to establish an unobviousness difference, see In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977).
Regarding claim 4, example of nonionic surfactant, in Leikhim et al, include those having formula R(C2H4O)nOH wherein R is aliphatic hydrocarbyl radical containing from about 8 to about 18 carbon atoms, and n = about 3 to about 12 (col. 1, lines 55-68).
Regarding claims 5 and 6, example of nonionic surfactant, in Leikhim et al, include those having formula R(C2H4O)nOH wherein R is aliphatic hydrocarbyl radical containing from about 8 to about 18 carbon atoms, and n = about 3 to about 12 (col. 1, lines 55-68). When R is aliphatic hydrocarbyl radical containing about 8 carbon atoms and n = about 3, it reads on diethylene glycol octyl ether in present claim 5. Additionally, it is the Office’s position that when R is an aliphatic radical having about 8 carbon atoms, it is a homolog of diethylene glycol hexyl ether. Case law holds that structural similarities have been found to support a prima facie case of obviousness. See, In re Wilder, 563 F.2d 457, 460, 195 USPQ 426, 429 (CCPA 1977) (adjacent homologs and structural isomers).
Regarding claim 7, Hsu et al teach that surfactants are present in amounts of about 6 to about 20% by weight (paragraph 0152). Leikhim et al teach that ethoxylated nonionic surfactant are present in amounts of about 5 to about 25% (col. 1, lines 55-59).
Regarding claims 8 and 9, examples of suitable anionic surfactants, in Hsu et al, include sodium salts of laureth sulfate (paragraph 0131) which reads on a salt containing alkyl sulfate anion in present claim 8 and sodium lauryl sulfate in present claim 9
Claims 2-3 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu et al (US 2014/0348887 A1) in view of Leikhim et al (US 4,284,532), Pich et al (US 2016/0168955 A1) and Hanson et al (US 2018/0251583 A1).
The discussion with respect to Hsu et al, Leikhim et al, and Pich et al in paragraph 8 above is incorporated here by reference.
Hsu et al, Leikhim et al and Pich et al are silent with respect to zwitterionic monomer.
However, Hanson et al in the same field of endeavor teach film-forming compositions comprising zwitterionic-functional polymer and methods of treating subterranean formation (abstract). Exemplary ethylenically unsaturated monomers that may be used as the zwitterionic monomer include betaine-containing monomer such as sulfobetaines represented by formula:
PNG
media_image1.png
79
252
media_image1.png
Greyscale
wherein A = O or NH; R1 is hydrogen or methyl, R2 is ethylene or propylene, R3 and R4 are alkyl typically containing from 1 to 4 carbon atoms; B is N, n = 1 to 4, and X- = SO3- (paragraph 0020). After treatment with the film-forming composition, oil permeability increased which may allow for an enhanced oil recovery in a subterranean formation (paragraph 0076). Therefore, in light of the teachings in Hanson et al, it would have been obvious to one skilled in art prior to the filing of present application to include the zwitterionic monomer, of Hanson et al, in the polymer, of Hsu et al, for above mentioned advantages
Response to Arguments
The rejections under 35 U.S.C. 103 as set forth in office action mailed 6/25/2025 are withdrawn in view of amendments and/or applicant arguments and/or new grounds of rejection set forth in this office action, necessitated by amendment.
While the grounds of rejection are changed, it was still deemed appropriate to address some of the arguments which would be pertinent to new grounds of rejection in this office action (See paragraph 11 below).
Applicant's arguments and Declaration under 37 CFR 1.132, filed 10/24/2025, have been fully considered but they are not persuasive. Specifically, applicant argues that (A) claimed polymerization, both in terms of polymerization technique and in the presence of glycol ether is distinct from that in the cited prior art and therefore would produce a distinct polymer product that is distinct from the polymer prepared by conventional emulsion polymerization of Hsu. In emulsion (or invert emulsion) polymerization no amphiphilic (co)polymer can be produced. Instead, RAFT micellar polymerization is the method used to prepare amphiphilic polymers which later self-assemble to offer distinct properties for specific application. DGHE does not work as a surfactant in the RAFT polymerization system but rather works as a mutual solvent to keep the micellar phase as a single phase. Thus, in the absence of DGHE, the prepared polymer would lack the desired performance properties. SDS accounts for 8.7% of the reaction in example 1 of present application. This is in contrast to the amount of about 0.2 to 5 wt% in Hsu et al. Thus, SDS surfactant concentration is way out of range used in normal emulsion polymerization; and (B) Leikhim’s nonionic surfactants are different from the claimed glycol ether, namely R2-O-(CH2)p-O-(CH2)q-O-R1 wherein R1 is hydrogen or acetate, R2 is a C1-C8 alkyl or phenyl and p and q are same or different and independently an integer of 1 to 6. For e.g., Leikhim’s C8H17(C2H4O)3OH (R = octyl and n = 3) is different from the claimed diglycol ether when R1 = octyl and p=q=2, namely C18H17(C2H4O)2OH. An increase in the number of ethoxylated groups from n = 2 (application) to n = 3 (Leikhim) as well as a shortened alkyl chain would affect HLB properties. As the number of ethoxylated groups increases, the molecule would be more attracted to water, thus increasing its HLB value. This is particularly significant in the context of RAFT micellar polymerization. Experimental results provided by the Qu Declaration (filed June 2, 2024) and Jensen Declaration (filed 4/29/2025) clearly show that the proppant suspension obtained for a polymer loading ranging from 0.15 to 0.3 based upon total weight of the fracturing fluid under low shear rate is good. The provided evidence shows that there is an unexpected results in enhanced particle dispersion capabilities when the claimed polymeric systems for particle dispersions are used in lower amounts compared with conventional carrier systems.
With respect to (A), Claims are written in product-by-process form. Case law holds that patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” See In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). Additionally, there is no data showing that addition of glycol ether to the polymer after it is formed by conventional polymerization process, as in Hsu et al, would not exhibit the presently claimed properties and can only be obtained by RAFT micellar polymerization process including higher amounts of surfactant SDS compared to low amounts of surfactant used in Hsu et al’s conventional polymerization process. Furthermore, contrary to applicant’s argument, Hsu et al teach that a nonionic amphiphilic polymer capable of forming a yield stress fluid is obtained (abstract).
With respect to (B), surfactant of Leikhim et al has the formula: R(C2H4O)nOH wherein R is aliphatic hydrocarbyl radical containing from about 8 to about 18 carbon atoms, and n = about 3 to about 12 (col. 1, lines 55-68). The term about 3 encompasses n = 2, hence the glycol ether of Leikhim may be R(C2H4O)2OH as in present claims where p and q = 2. As stated earlier, there is no comparative data showing the addition of glycol ether to the polymer formed by conventional emulsion polymerization would not exhibit the results being exhibited by a polymer prepared by the different RAFT micellar polymerization process.
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.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KARUNA P REDDY whose telephone number is (571)272-6566. The examiner can normally be reached 8:30 AM to 5:00 PM M-F.
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.
/KARUNA P REDDY/Primary Examiner, Art Unit 1764