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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 07/29/2026 has been entered.
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.
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.
Claims 1, 3, 5-6 and 10-17 are rejected under 35 U.S.C. 103 as being unpatentable over Auman et al. US2020/0140615 A1 in view of Hwang et al. US KR101949316B1.
Auman teaches polyamic acid solution derived from tetracarboxylic acid and diamine components to generate polyimide films for use in electronic display applications (abstract and para [0532]).
Reference Hwang discloses polyamic acid compositions with improved storage stability and polyimide films for electronics applications (paras [0001] and [0084])
Regarding claim 1, Auman discloses (reference claims 1-4) that the polyamic acid comprises three or more tetracarboxylic acid components and one or more diamine components. The tetracarboxylic acid components are derived from dianhydrides where two of the dianhydride can be selected to be 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). Further the diamines can be selected to be p-phenylenediamine (PPD) and 2,2'-bis(trifluoromethyl) benzidine (TFMB). Auman adds that solvent N-methyl-2-pyrrolidone (NMP) can be selected as a high boiling solvent to generate the polyamic acid solution. The boiling point of NMP solvent is 202 oC, which meets the claimed requirement.
Auman highlights (para [0451]) that rod-like monomers such as BPDA and PPD form highly rod-like polyimide polymer chains orienting in the plane of the film giving low in-plane CTE property. While the fluorinated monomers like 6FDA and TFMB tend to give higher-transparency polyimides due to the electronic and steric effects of the fluorinated groups. Thus, guiding a skilled artisan towards the combination of the above monomers to generate the polyimide films with tailored properties of CTE and transparency.
Aumun notes that additional cosolvent can be utilized in the polyamic acid solution (para [0182]), but does not specifically list methanol or ethanol as cosolvents. Aumun however adds that specification is not restrictive and various modifications and changes can be made by one of ordinary skill in the art (para [0733]).
Analogous reference Hwang teaches inclusion of an alcohol cosolvent used as an additive for the creation of polyamic acid, which can be selected to be ethanol (Hwang para [0042]). Advantageously, Hwang provides the motivation to utilize ethanol in the polyamic acid solution since it enhances its storage stability at room temperature and induces faster imidization reaction (paras [0019] and [0020]).
It would have been obvious to one of ordinary skilled in the art before the effective filing date of the invention to have utilized in Aumun’s polyamic composition ethanol as a cosolvent as taught by Hwang for the same application of creating a polyamic acid with improved room temperature storage stability.
Auman and Hwang do not address the permittivity and the surface resistance properties of the polyimide films, however owing to the closeness of the materials disclosed, it would necessarily follow that the polyimides provided by the combination of Auman and Hwang would possess the permittivity and surface resistance as defined by the claim.
Regarding claims 3 and 5, as discussed when addressing claim 1, the dianhydride monomer component and ethanol meet the claimed requirements, thus the solubility requirement would be met. Since the polyamic acid has a lower solubility in the second cosolvent ethanol, it would be obvious to utilize small amounts of the second solvent complying with the claimed requirements in order to prevent the precipitation of the polyamic acid.
Regarding claim 6, Auman’s anhydride monomer BPDA, as discussed when addressing claim 1, would behave in a similar fashion (as instant specification example 1, page 22), where the majority of the S-BPDA monomer participates to create polymerization units (with the diamine monomer), while a small portion of it, reacts with ethanol to create a ring-opened structure which does not participate in the polymerization reaction.
Regarding claim 10, Auman teaches a solid content of 15-20 wt%, meeting the claimed requirement (para [0187]).
Regarding claim 11, Auman provides Example 1 with the viscosity of a polyamic acid solution of ~12000 cps which is measured at 25 oC (para [0714]). Obvious polyamic acid solution derived from monomers BPDA, 6FDA, PPD and TFMB in the solvent system of NMP and ethanol, as discussed when addressing claim 1, attaining similar molecular weight and solid content level as that of Auman’s Example 1, would be reasonably expected to satisfy the viscosity requirement as defined by the claim.
Regarding claim 12, Auman teaches the weight average molecular weight to be between 160,000 and 220,000 g/mol, meeting the claimed requirement (para [0200]).
Regarding claim 13, Aumun teaches incorporation of inorganic fillers in the polyamic acid solution, meeting the claimed requirement (para [0215]).
Regarding claim 14, Auman teaches the in-plane coefficient of thermal expansion (CTE) of the polyimide film to be less than 20 ppm/° C, meeting the claimed requirement (para [0028]).
Regarding claims 15 and 17, Auman teaches the Tg of the cured polyimide film to be greater than 350 oC, meeting the claimed requirement (paras [0024] and [0029]).
Regarding claim 16, Hwang teaches reaction temperature of 50 oC, for preparing polyamic acid composition, meeting the claimed requirement (para [0096]).
Response to Arguments
Applicant's arguments filed 07/29/2026 have been fully considered, please see the response below.
Applicant argues (Remarks pages 6-7) that Aumun fails to provide the second solvent which is methanol or ethanol. Applicant further discusses that in instant specification’s comparative examples 2 and 4 do not satisfy the required permittivity and surface resistance due to the absence of methanol or ethanol in the polyamic acid composition.
In response, it is acknowledged that Aumun does not specify methanol or ethanol as a cosolvent, and therefore the rejection under 35 U.S.C. § 103 over Aumun is withdrawn. However, upon further consideration, the amended claims are now rejected on a new ground(s) of rejection over Aumun in view of Hwang, where the secondary reference Hwang teaches incorporation of methanol or ethanol to improve storage stability of the polyamic acid. Since the polyimides of Aumun and Hwang are derived from the required monomers and solvent combination, they would be reasonably expected to possess the desired properties, as discussed in the rejection above.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Surbhi M Du whose telephone number is (571)272-9960. The examiner can normally be reached M-F 9:00 am to 5:00pm.
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/HEIDI R KELLEY/Supervisory Patent Examiner, Art Unit 1765
/S.M.D./
Examiner
Art Unit 1765
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