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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 December 11, 2025, 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.
Claims 1, 2 and 5-7 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2021/040127 Kim et al with evidence from Tri-p-cresyl phosphate.
Regarding claim 1, Kim teaches a polyimide film (paragraph 0001) comprising
a first plasticizer and a second plasticizer (paragraph 0063 teaching “at least one” which is interpreted as a range of one or more),
wherein each of the first plasticizer and the second plasticizer has a molecular weight of 326 g/mol and 368 g/mol, respectively (paragraph 0020 teaching triphenyl phosphate, (C6H5)3PO4 = 326 g/mol, and tricresyl phosphate, C21H21O4P = 368 g/mol. Please note that the molecular weight of each compound can be found by adding the components in the molecular formula).
Kim does not explicitly teach the content of the plasticizers with respect to the catalyst, a film elongation of 120% or more, a film strength of 210 MPa or more, a residual amount of 56% by weight or more when being thermally decomposed at a temperature of 1000°C, a weight ratio of the plasticizers or the true density of the polyimide film.
However, Kim does teach the total weight of the plasticizer as 0.1 to less than 3.0 wt% (paragraph 0019). Kim further teaches that the addition of plasticizer increases flexibility by providing free volume and contributes to the suppression of bubble formation (paragraph 0063), and that the ratio of the diamine and dianhydride may be adjusted (paragraph 0027) and contribute to the elasticity (paragraphs 0046 and 0047) and viscosity (paragraph 0028) of the film, which in turn contribute to the film elongation, film strength, true density and residual amount.
Since the instant specification is silent to unexpected results, the specific plasticizer content, film elongation, film strength, true density and residual amount are not considered to confer patentability to the claims. As the physical and optical characteristics are variables that can be modified, among others, by adjusting the parameters of the method, the precise plasticizer content, film elongation, film strength, true density and residual amount would have been considered a result effective variable by one having ordinary skill in the art before the effective filing date of the invention. As such, without showing unexpected results, the claimed plasticizer content, film elongation, film strength, and residual amount cannot be considered critical. Accordingly, one of ordinary skill in the art, before the effective filing date of the invention, would have optimized, by routine experimentation, the plasticizer content, film elongation, film strength, true density and residual amount (by adjusting amounts of the diamine and dianhydride) to obtain the desired physical characteristic (In re Boesch, 617 F.2d. 272, 205 USPQ 215 (CCPA 1980)), since it has been held that where the general conditions of the claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. (In re Aller, 105 USPQ 223). See MPEP 2144.05 Section II.
Regarding claim 2, Kim teaches that a difference in molecular weight between the first plasticizer and the second plasticizer is 42 g/mol (paragraph 0020 teaching triphenyl phosphate, (C6H5)3PO4 = 326 g/mol, and tricresyl phosphate, C21H21O4P = 368 g/mol. Please note that the molecular weight of each compound can be found by adding the components in the molecular formula).
Regarding claim 5, Kim teaches that each of the first plasticizer and the second plasticizer is a phosphorus-based plasticizer (paragraph 0052).
Regarding claim 6, Kim teaches that the first plasticizer or the second plasticizer is triphenyl phosphate and tricresyl phosphate (paragraph 0020).
Regarding claim 7, Kim teaches that the polyimide film is formed from:
a dianhydride monomer comprising pyromellitic dianhydride (paragraph 0015), and
a diamine monomer comprising 4,4'-oxydianiline or p-phenylenediamine (paragraph 0015).
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over WO 2021/040127 Kim et al as applied to claim 1 above, and further in view of Applicant’s Admitted Prior Art (AAPA).
Regarding claim 9, Kim does not teach manufacture of a graphite sheet. However, Kim does teach manufacture of the polyimide film. AAPA teaches manufacture of a polyimide film where the film is used to manufacture a graphite sheet (as-filed spec, paragraph 0004). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to include the graphite sheet use of AAPA for the product of Kim because this expands the variety of uses for the polyimide film.
Response to Arguments
Applicant's arguments filed December 11, 2025, have been fully considered but they are not persuasive.
Applicant argues that Kim does not consider the plasticizer ratio and its benefits. However, the prior art need not have the same reasons or recognize the same benefits as Applicant in order to read on the claim.
Applicant argues that the provided data shows a benefit of the specific true density claimed. However, the data provided is insufficient to establish criticality. The data does not provide values for true density, only conclusions. Furthermore, the data shows that higher values were undesirable (as-filed spec paragraph 136). The data also fails to provide examples around the end points and lower than the claimed range.
Applicant argues that the invention focuses on objectives that Kim does not acknowledge. However, the prior art need not have the same reason as Applicant for obtaining a particular product that reads on the claims.
Applicant argues that Kim uses a plasticizer content different than that of the claim. However, the disclosure supports an optimization rationale, where one of ordinary skill in the art may adjust the amounts to obtain the desired properties. Furthermore, Applicant has not shown that the plasticizer to catalyst ratio is critical.
Applicant argues that the film strength and elongation are not discussed by Kim. However, again, these features are affected by the composition of the film and therefore are optimizable as discussed above. Applicant further appears to argue that this feature is not optimizable as it would require undue experimentation. However, the prior art shows how these features are modified such that one of ordinary skill in the art would be able to determine an appropriate range in which to test. Applicant has not shown why the teaching of the prior art do not support routine experimentation.
Conclusion
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/MEGHA M GAITONDE/Primary Examiner, Art Unit 1781