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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 August 14, 2026 has been entered.
Summary
The Applicant’s arguments and claim amendments received on July 29, 2026 are entered into the file. Currently, claims 1 and 8 are amended; claims 2-7, 9-14, and 19-25 are canceled; claims 15-18 are withdrawn; resulting in claims 1 and 8 pending for examination.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 04/29/2026 has been considered by the examiner.
Specification
The substitute specification filed July 29, 2026 complies with the requirements set forth in 37 CFR 1.125(b) and (c) and has been entered.
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.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (CN 109337070, machine translation previously provided) in view of Lee et al. (US 2005/0096429, previously cited).
Regarding claim 1, Yin et al. teaches a film (composite polyimide substrate) obtained using a resin composition (substrate matrix, polyester imide) [0010]. The resin composition is obtained by reacting an acid dianhydride and a diamine, where the acid dianhydride can be 4,4'-bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-ylcarbonyloxy) biphenyl (BP-TME), and the diamine can be 2,2'-bis(trifluoromethyl)diaminobiphenyl (TFMB) ([0009], [0036], [0041], see Example 10 in Table 2). As shown in Table 2, the (BP-TME)-TFMB film has a dielectric constant of 3.1 and a dielectric loss tangent (tan δ) of 0.0020. The ratio of diamine to dianhydride is preferably in the range of 0.95 to 1.05, or 1:1 (substantially equimolar ratio), where high heat resistance and high elastic modulus can be achieved while maintaining dielectric properties if the dianhydride and diamine react in approximately equal amounts [0042].
Although Yin et al. teaches that the resin composition has a low dielectric constant, low dielectric loss tangent, low water absorption, good mechanical strength, and exhibits minimal dimensional changes at high temperatures, such that the films are suitable for use in circuit boards ([0010]), the reference does not expressly teach that polytetrafluoroethylene (PTFE) particles are contained in the resin composition, or that a dielectric constant of the film is 3.0 or less.
However, in the analogous art of polyester imide films, Lee et al. teaches a thin film used in high-speed digital circuitry, made of a polymeric composite comprising a polyimide component and a fluoropolymer component (Abstract). The polymeric composite is created by incorporating microscopic fluoropolymer powders into a polyamic acid followed by an imidization process to form the polyimide, resulting in continuous and/or discontinuous domains of fluoropolymer integrated into the polyimide ([0007]-[0008]). Lee et al. teaches that the fluoropolymer micro powders can be dispersed in the polyimide component, where the fluoropolymer and polyimide are initially combined and subjected to sufficient shear and temperature to eliminate or otherwise minimize unwanted fluoropolymer micro powder agglomeration, thereby achieving superior phase interpenetration between the polyimide and fluoropolymer ([0019], [0025]). Lee et al. teaches that such films have high mechanical toughness as well as high dielectric strength, where the fluoropolymer provides low loss, low dielectric constant, low water absorption, and chemical resistance, while the polyimide provides high mechanical strength, high glass transition temperature, resistance to chemical and thermal degradation, and high dielectric strength ([0016], [0032]). Lee et al. teaches that fluoropolymers can include polytetrafluoroethylene (PTFE) ([0034], [0043]).
Lee et al. teaches that the fluoropolymer micro powder has an average particle size between 20 nm and 5.0 microns (Abstract), which overlaps the claimed ranges for the size and average particle diameter of the PTFE particles. In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art, a prima facie case of obviousness exists. See MPEP 2144.05(I). Lee et al. teaches that by using micro powder particles of this size, the final polyimide product will generally have superior phase inter-penetration between the polyimide and fluoropolymer than when larger particles of fluoropolymer are dispersed into the polyimide [0025].
Lee et al. further teaches that the fluoropolymer component is present in a weight ratio from 10 to 60 percent (Abstract, [0024]), which overlaps the claimed range of 40 to 80 wt%. In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art, a prima facie case of obviousness exists. See MPEP 2144.05(I). Lee et al. teaches that the weight percent loading of the fluoropolymer component in the polyimide component should generally be greater than about 30 weight percent, but that as weight percent loading of the fluoropolymer component increases, the mechanical properties of the composite film tend to decline [0063]. Lee et al. further demonstrates the effects of adjusting the content of fluoropolymer between 20% and 60% on the tensile properties, dielectric constant, dielectric loss, coefficient of thermal expansion (CTE), tensile stress, elongation, and water absorption of the polyimide film (Table 2). In particular, Examples E1-E5 in Table 2 of Lee et al. demonstrate that increasing the fluoropolymer content significantly improves the dielectric constant, dielectric loss, and water absorption properties but also consequently increases the coefficient of thermal expansion of the film and decreases the tensile stress and elongation of the film.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the film taught by Yin et al. by dispersing and distributing PTFE particles having the claimed particle size and average particle diameter in the polyester imide resin composition matrix at a weight percentage within the claimed range, as taught by Lee et al., in order to improve the dielectric properties, dissipation loss, and water absorption while maintaining a good balance of mechanical properties, including the coefficient of thermal expansion, tensile stress, and elongation of the film. It would, moreover, have been obvious to one of ordinary skill in the art to have determined an optimum value of a result-effective variable such as the dielectric constant of the composite polyimide film through routine experimentation, such as by adjusting the content of PTFE particles within the claimed range, especially given the teachings in Lee et al. showing that the dielectric properties can be improved by increasing the content of fluoropolymer at the expense of a reduction in mechanical properties. See MPEP 2144.05(II).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (CN 109337070, machine translation via EPO provided) in view of Lee et al. (US 2005/0096429, newly cited) as applied to claim 1 above, and further in view of Sato et al. (KR 2017-0134610, machine translation previously provided).
Regarding claim 8, Yin et al. in view of Lee et al. teaches all of the limitations of claim 1 above. Although Lee et al. teaches that the fluoropolymer micro powder can be dispersed in the polyimide component via a dispersing surfactant ([0019], [0056]), the reference does not expressly teach that the surfactant is a fluorine-based surfactant.
However, in the analogous art of polyester imide films, Sato et al. teaches a polyimide film obtained by mixing a non-aqueous dispersion of a fluorine-based resin and a polyimide precursor solution, followed by imidizing the precursor solution and heat-treating the film to remove the solvent ([0066], [0155]-[0158]). The polyimide precursor solution is obtained by reacting a tetracarboxylic dianhydride with a diamine compound, and the non-aqueous dispersion of a fluorine-based resin may be a PTFE micropowder ([0083]-[0086], [0131]-[0132]). Sato et al. teaches that a fluorinated additive (fluorine-based surfactant) having a fluorinated group and a lipophilic group can be added to the non-aqueous dispersion in order to lower the surface tension of the dispersion medium, thereby improving the dispersibility of the micropowder of fluorinated resin (PTFE particles) [0094]. Sato et al. teaches that the non-aqueous dispersion has excellent redispersibility and that the micropowder of fluorine resin can be uniformly mixed when added to a polyimide precursor solution [0130].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the film taught by Yin et al. in view of Lee et al. be selecting a fluorine-based compound as the surfactant, as taught by Sato et al., in order to improve the dispersibility of the PTFE particles in the polyimide precursor solution.
Response to Arguments
Response-Specification
The previous objection to the specification is overcome by the amendments to paragraphs [18], [30], [56], [94], and [122] in the substitute specification filed July 29, 2026, in which each instance of the term “bi-phenol bis(trimellitate anhydride)” was amended to recite --biphenyl bis(trimellitate anhydride)--, consistent with the language used in claim 1.
Response-Claim Rejections - 35 USC § 112
The previous rejection of claims 1 and 4-8 under 35 U.S.C. 112(b) as being indefinite is withdrawn in light of the Applicant’s amendment to claim 1 in the response filed July 29, 2026, in which the limitation at issue was deleted from the claim.
Response-Claim Rejections - 35 USC § 103
Applicant's arguments, see pages 5-8 of the remarks filed July 29, 2026, with respect to amended claim 1 have been fully considered but they are not persuasive.
With respect to the previous rejections under 35 U.S.C. 103 based on Yin et al. in view of Lee et al., the Applicant argues that the teachings of Lee fail to provide sufficient motivation to one of ordinary skill in the art to modify the disclosure of Yin with Lee by adding PTFE particles at the claimed amount because doing so would sacrifice the key advantage espoused in Yin (dimensional stability or low CTE) for an incremental reduction in dielectric constant.
This argument is not persuasive. As to the Applicant's argument that the "key advantage" of Yin et al. is dimensional stability (low CTE), it is noted that Yin et al. teaches a variety of features that are important to the resin film, including low water absorption, low linear thermal expansion, high heat resistance, low dielectric constant, low dielectric loss tangent, and good environmental stability ([0010]-[0011]). As acknowledged by the Applicant, Lee et al. recognizes that the addition of PTFE particles to the film enables low dissipation loss and low water absorption to be achieved, but that as the weight percentage of PTFE increases, the mechanical properties of the film tend to decline ([0063], Table 2). One of ordinary skill in the art would therefore recognize based on the teachings of Yin et al. and Lee et al. that the PTFE particles can be added at an amount necessary to achieve the desired balance of properties for a particular application of the resin film – where a higher content of PTFE particles results in decreased water absorption and dielectric loss, while a lower content of PTFE particles exhibits improved dimensional stability, tensile stress, and elongation at the expense of higher water absorption and worse dielectric properties. Given that Yin et al. recognizes all of these properties as important, the modification of adding PTFE particles to the film based on the teachings of Lee et al. is consistent with the objectives of Yin et al. and does not destroy the stated advantage thereof.
The Applicant further argues on pages 7-8 of the remarks that the data shown in the present application rebuts the motivation to combine which is based on the position that the dielectric constant is a result-effective variable that would have been optimized through routine experimentation by adjusting PTFE content. In particular, the Applicant cites Examples 4-6 in Table 1, which include BP-TME and TFMB with PTFE particles at 40, 60, and 80 wt% respectively, as a comparison with Lee’s Table 2. The Applicant submits that the results regarding the coefficient of thermal expansion remaining unchanged at 19 ppm/K across the entire 40 to 80 wt% range is unexpected and could not have been predicted from the cited combination, and cannot support the argument of a result-effective variable that would have been optimized through routine experimentation.
These arguments are not persuasive to rebut the prima facie case of obviousness set forth above. As acknowledged by the Applicant, the position taken in the rejection above is that the dielectric constant is a result-effective variable that would have been obvious to optimize through routine experimentation by adjusting PTFE content. Lee et al. explains that the fluoropolymers provide advantageous properties such as low loss, low dielectric constant, and low water absorption, while the polyimide provides advantageous properties such as high mechanical strength [0016]. Table 2 in Lee et al. further demonstrates a clear relationship between the loading of fluoropolymer and the dielectric constant of the composite film, where the dielectric constant decreases as the fluoropolymer content increases between 20 wt% and 60 wt%. The claimed range of 3.0 or less for the dielectric constant can therefore be predictably achieved via routine experimentation by adjusting the content of fluoropolymer particles in the composite film to amounts within the claimed range. The data shown in Examples 4-6 and Comparative Example 3 in Tables 1-2 do not rebut this assertion, as the dielectric constant (Dk*) is shown to follow an identical trend of decreasing as the fluoropolymer content increases between 0%, 40 wt%, and 60 wt%.
With respect to Applicant’s assertion that the results regarding the coefficient of thermal expansion remaining unchanged at 19 ppm/K across the entire 40 to 80 wt% range are unexpected based on the prior art, it is noted that the data provided in the instant specification is insufficient to establish a showing of unexpected results.
First, the data shown in Tables 1-2 of the instant specification does not provide an adequate comparison to the prior art. Although Tables 1-2 demonstrate how the dielectric constant (Dk*), dielectric loss (Df*), and coefficient of thermal expansion (CTE) are affected by varying the content of PTFE particles in the composite polyimide film, the data provided by the Applicant does not show the results of varying the content of PTFE particles on film properties such as tensile stress, elongation, peel strength, or water absorption. In contrast, Table 2 of Lee et al. shows how each of the above film properties is affected by varying the fluoropolymer content. Jang et al. (KR 2015-0069318, machine translation provided) similarly teaches that the content of micro-sized fluoropolymer is preferably 10 to 90 weight%, preferably 20 to 60 weight%, where an amount less than the above range does not obtain a low dielectric constant, while an amount greater than the above range makes the film properties weaken, which may cause problems such as the film tearing easily or breaking [0121]. The prior art therefore recognizes disadvantages associated with high amounts of PTFE particles, such as the reduction in mechanical properties; however, the data provided by the Applicant does not show these properties, such that a direct comparison cannot be made. See MPEP 716.02(e).
As to the data in Examples 4-6 shown in Table 1 and the Applicant’s assertion regarding the coefficient of thermal expansion remaining unchanged at 19 ppm/K across the entire 40 to 80 wt% range being unexpected, it is noted that the data is only reported with two significant figures (to the ones digit), such that it is not clear whether the CTE property shown for Examples 4-6 is in fact “unchanged” across the entire claimed range. Rather, the reported value of 19 ppm could encompass values within the range of 18.5 ppm to 19.4 ppm based on standard rounding rules. Furthermore, it is noted that not only the CTE value, but also the dielectric constant and dielectric loss properties remain constant at 19 ppm, 2.3, and 0.0021, respectively, between 60 wt% and 80 wt% of PTFE particles. The difference between the content of PTFE particles being 60 wt% and 80 wt% does not appear to have statistical or practical significance, as the inclusion of 80 wt% of PTFE particles in Example 6 is not shown to have any improvement over Example 5 which includes 60 wt% of PTFE particles. See MPEP 716.02(b)(I).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to REBECCA L GRUSBY whose telephone number is (571) 272-1564. The examiner can normally be reached Monday-Friday, 8:30 AM-5:30 PM.
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/REBECCA L GRUSBY/Primary Examiner, Art Unit 1785
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