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 .
Election/Restrictions
Applicant's election with traverse of claims 1-15 in the reply filed on 1/5/26 is acknowledged. The traversal is on the ground(s) that there is no burden. This is not found persuasive because, as shown in the restriction requirement, the claims belong to different classes, and for the fact that the art is very crowded, there is significant burden. Please note that long gone are the days where references in a subclass could be found in a shoe box.
The requirement is still deemed proper and is therefore made FINAL.
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.
Claim 15 is 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.
Claim 15 recites water permeability in Kg/m2/hr. This is indefinite because the permeability would depend on the applied pressure differential as well, without which the actual permeability cannot be compared.
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, 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) 1-15 are rejected under 35 U.S.C. 103 as being unpatentable over Leblanc et.al, “Influence of solvent and non-solvent on polyimide asymmetric membranes formation in relation to gas permeation,” Separation and Purification Technology 22-23 (2001) 277–285, in view of Chinn et al (US 2014/0100295).and Xu et al (US 2019/0275471.)
Claims are directed to a method of making a polyimide membrane from a dianhydride and a phenylenediamine. Claims include (1) synthesis of the polyimide, (2) casting the membrane to produce a self-supported membrane, and (3) the resultant membrane thickness of 30-100 microns.
Leblanc teaches the details of making 6FDA - m-phenylenediamine (MPDA) polyimide membrane by casting on glass plate. Leblanc teaches the details of the casting process, solvents and non-solvents (water, alcohols: see the tables.) The Leblanc paper is about casting and characterization of polyimide membranes. While Leblanc does not explicitly state that the membrane is removed from the glass plate, this step is implied or obvious. The membrane comes off from the glass plate when immersed in the coagulant solution like water or alcohol. Also, the glass is not porous and must be removed to make the membrane function. Regarding the membrane thickness, Leblanc is silent on the total thickness, but provides detailed study on the skin layer thickness. Total thickness of the membrane is observable in the SEM pictures. Since the membrane characteristic is based on the skin, and the spongy layer is only for mechanical support, the total thickness is not critical and would depend on how much strength the membrane needs, and can be optimized.
Leblanc does not teach the details of the synthesis of the polyimide, except saying that it is made by polycondensation. However, actual synthesis of polyimide is well-known, and can be seen in the Chinn reference. See Chinn, under “Polymerization and Imidization Reactions”. [0084] – [0105]. The monomers are 6FDA (as in claim 2) and phenylenediamines. It would have been obvious to one of ordinary skill to look up relevant references to obtain such details because Leblanc fails to provide the details.
Chinn teaches details of synthesizing the polyimide with 6FDA [0089] and various phenylenediamines [0090]. The proportion of monomers is about 50/50 [0092]. Regarding the first solvent, [0095] teaches that a solvent with a high boiling point is suitable, and suggests examples in Table 1. The cresols applicant recites are obvious alternates that meet the criteria, and is not patentable unless otherwise shown. Chinn also teaches that polycondensation takes place at 160-200C. [0097] as in claim 6. Polyimide is precipitated in methanol – examples. Chinn also teaches casting the membrane in to flat sheets using the well-known process – [0128].
Xu teaches polyimide membranes formed by 6FDA and phenylenediamines, made particularly from the p-phenylenediamines of claims 3 and 4 – see “2,3,5,6-tetra Methyl-1,4-phenylenediamine (durene).” [0031]. JP teaches flat sheet (as known in the art: [0003]). Xu also teaches thickness in the range claimed – see [0029] – 0.022 mm thick, and the SEMs. Xu teaches having diamines with no rotational freedom and suggests the recited diamines. Therefore, it would have been obvious to one of ordinary skill in the art to use the teaching of Xu in the teaching of Leblanc to have the advantages as taught by Xu.
Other dependent claims: claim 7: The casting solution is 25% polyimide, but this can also be optimized based on the cloud point diagram – fig. 2.
Claims 9-12: see the SEMs in Leblanc.
Claims 13-14: inherent material property.
Claim 15: since the same or similar membrane the flux would be inherently the same.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KRISHNAN S MENON whose telephone number is (571)272-1143. The examiner can normally be reached Flexible, but generally Monday-Friday: 8:00AM-4:30PM.
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, Prem C Singh can be reached at 571-272-6381. 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.
/KRISHNAN S MENON/Primary Examiner, Art Unit 1777