DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claims 1, 2 and 11 are pending as amended on 8/31/2026.
Claim 1 has been amended to narrow the range of phosphorus-based compound, and, to require a film which has a thickness of 75 micron or more and 0 bubbles per 1 m2. The rejections of record have been modified, as necessitated by Applicant’s amendment. Therefore, this action is properly made final.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn. 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 Objections
Claim 1 is objected to because of the following informalities:
The last three lines of claim 1 are grammatically confusing. As evidenced by Applicant’s arguments (filed 8/31/26, p 4) that claim 1 has been amended to define the polyimide film as having a thickness of 75 micron or more, Applicant clearly intended to delete the word “when” in the third to last line of claim 1. Applicant should delete “when” to resolve the grammatical issue. Appropriate correction is required.
Claim Rejections - 35 USC § 103
Claim(s) 1, 2 and 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Back et al (WO 2019132184; previously included machine translation cited herein) in view of Maki et al (US 5665802), and further in view of Fukukawa et al (US 2016/0053135).
As to claims 1, 2 and 11, Back discloses a polyimide film for manufacturing a flexible copper-clad laminate [0001]. Back discloses that polyimide film is used as a protective film for thin circuit boards [0004] (meeting instant claim 11). The film is obtained by imidizing a polyamic acid derived from a monomer mixture including at least three dianhydride monomers selected from a group consisting of BTDA, BPDA, PMDA and ODPA [0028], as well as diamine monomers including a diamine monomer having a carboxylic acid functional group, a diamine not including a carboxylic acid functional group, and PPD [0029]. Back exemplifies a polyimide film derived from PMDA (30 mol%), BPDA (50 mol%) and BTDA (20 mol%) as dianhydrides and from PPD (65 mol%), ODA (20 mol%) and DABA (15 mol%) as diamines (see example 1 in Table 1 on p 14 of the original document). The molar percentages of each of the monomers in Back’s example 1 fall within the corresponding ranges recited in instant claims 1 and 2.
Back fails to teach that a phosphorus-based compound is contained in an amount of 2.5-4.0 wt%.
Maki teaches that polyimide is often used in the manufacture of a flexible printed circuit board in a form laminated with a copper foil (col 1, lines 29-35). Maki discloses a polyimide formed from diamines and dianhydrides, wherein PPD and ODA are named as preferred diamines (col 3, lines 38-40) and PMDA and BPDA are named as preferred dianhydrides (col 4, lines 40-44) (and BTDA is further named as an example dianhydride; col 4, line 21). The polyimide is obtained by conversion of polyamic acid (“polyamide acid”) (col 4, lines 60-65).
Maki teaches adding an organic phosphorus compound to the solution of polyamic acid, prior to forming a film and converting to a film of polyimide containing an organic phosphorus compound (col 5, lines 27-42). The amount of the organic phosphorus compound is 0.5 to 5 wt % based on polyimide (col 5, lines 43-55). Given that the polyimide is entirely formed from dianhydride and diamine components, the weight percentage range based on polyimide taught by Maki is substantially equivalent to a weight percentage based on the solid content of dianhydride and diamine components used to form the polyimide. Maki teaches that if the content of phosphorus compound is less than 0.5 weight%, the effect to improve mechanical strength is scarcely noticeable, while if the phosphorus compound exceeds 5 wt%, it causes discoloration (col 5, lines 48-55). Maki names triphenyl phosphate as an example phosphorus compound (col 5, lines 57-58).
Considering Maki’s disclosure, the person having ordinary skill in the art would have been motivated to include triphenyl phosphate in a polyimide film formed from monomers including PMDA, BPDA, PPD and ODA in order to improve the mechanical strength and flexibility thereof. It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a polyimide film derived from PMDA (30 mol%), BPDA (50 mol%) and BTDA (20 mol%) as dianhydrides and from PPD (65 mol%), ODA (20 mol%) and DABA (15 mol%) as diamines, as disclosed by Back, by further including triphenyl phosphate, as disclosed by Maki, in order to improve the strength and flexibility of Back’s film. It would have been obvious to the person having ordinary skill in the art to have included the triphenyl phosphate in any amount within Maki’s disclosed range of 0.5-5 wt%, including an amount which falls within the presently claimed range of 2.5-4.0 wt%, in order to improve the mechanical properties of the film without causing undesired discoloration thereof.
As to the presently recited thickness:
Back teaches a structure in which the polyimide film is laminated to copper foil via an adhesive layer [0112]. Back exemplifies a film with an average thickness of 15 µm [0118]. Maki teaches that when the thickness of a polyimide film to be laminated with copper foil and adhesive layer is increased, physical properties of the film (such as repeated flexural strength) can be deteriorated, which contrasts with a desire to improve the mechanical strength of a polyimide used for lamination with a copper foil (col 1, lines 29-29). Maki teaches that the thickness of polyimide film containing organic phosphorus compound may properly be set as necessary, and there is no particular limitation. Maki teaches that because the polyimide film containing a phosphorus compound is improved in mechanical strength, its film thickness is desired to be 12.5-150 µm, with a range of 75-130 µm disclosed as being preferred, for improvement in flexibility (col 7, lines 28-34).
Considering Maki’s disclosure, one having ordinary skill in the art would have recognized that the thickness of a polyimide film which contains a phosphorus compound can be appropriately selected in order to achieve a desired flexibility while also achieving a desired mechanical strength. It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a polyimide film, as suggested by modified Back, having any thickness within Maki’s disclosed range of 12-150 µm, in order to achieve a desired mechanical strength and flexibility, including a thickness of 75 µm or greater.
As to the presently recited elastic modulus, surface roughness and bubble concentration:
Modified Back suggests a film, as set forth above, which is derived from PMDA (30 mol%), BPDA (50 mol%) and BTDA (20 mol%) as dianhydrides and from PPD (65 mol%), ODA (20 mol%) and DABA (15 mol%) as diamines, which contains 2.5-4.0 wt % triphenyl phosphate, and which has a thickness of 75 µm or greater.
Modified Back is silent as to surface roughness, elastic modulus and bubble concentration. However, as established above, the cited prior art (Maki) recognizes the existence of a tradeoff associated with increasing triphenyl phosphate content: the tensile strength and flexibility increase (desirable) while appearance is “slightly changed” at the highest amount of 5.0 wt% (Maki, Table 1 and col 5, lines 48-55). Considering Maki’s disclosure, it would have been obvious to the person having ordinary skill in the art to have formed Back’s polyimide film having any amount of triphenyl phosphate within Maki’s disclosed range of 0.5 to 5 wt% in order to achieve the desired tradeoff between tensile strength, flexibility, and discoloration, including an amount within the presently claimed range of 2.5-4.0 wt% TPP.
The examples and comparative examples in the instant specification show that, when made via substantially the same method and formed from the same monomers in substantially the same amounts as disclosed in modified Back, a polyimide film having a TPP content within a range of 2.5 to 4.0 wt % has properties within the presently claimed ranges. There is reasonable basis to conclude, therefore, that a polyimide film having a TPP content within a range of 2.5 to 4.0 wt%, as suggested by modified Back, at least has mechanical properties (including elastic modulus) which are substantially the same as those of the instant examples, i.e., within the presently claimed ranges.
As to surface roughness and bubble concentration:
Fukukawa teaches that when a polyamic acid coating is heated drastically to imidize, the solvent inside the coating film may cause bubbles, or the coating film surface may have irregularities due to the release of solvent. Fukukawa teaches that accordingly, it is preferred to raise the temperature of the coating film gradually [0125-127].
Considering Fukukawa, the person having ordinary skill in the art would have recognized that bubbles and surface roughness of a polyimide film are defects which can be mitigated by appropriate film formation and imidization conditions, and, the person having ordinary skill in the art would have been motivated to adjust the rate of temperature increase when imidizing a polyamic acid coating in order to improve surface regularity and prevent bubble formation. It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a polyimide film having a thickness of 75 µm or greater derived from PMDA (30 mol%), BPDA (50 mol%) and BTDA (20 mol%) as dianhydrides and from PPD (65 mol%), ODA (20 mol%) and DABA (15 mol%) as diamines, and, which contains 2.5-4.0 wt % triphenyl phosphate, via coating and heating a polyamic acid solution, as suggested by modified Back, by controlling the raise in temperature during the polyamic acid imidization in order to decrease bubble formation and surface irregularities (as taught by Fukukawa), including to a bubble concentration and surface roughness within the presently claimed ranges.
Response to Arguments
Applicant's arguments filed 8/31/2026 have been fully considered.
Applicant argues (p 5) that there are no examples in Back and Maki which have TPP within the claimed range and properties as presently recited. Applicant similarly argues (p 6) that Fukukawa does not present any example of a film having TPP within the claimed range and properties as presently recited. This argument fails to establish nonobviousness for at least the reason that disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments (MPEP 2123). Additionally, the rejection over Back in view of Maki and Fukukawa does not assert that any one of Back or Maki or Fukukawa individually discloses or suggests a film according to the present claims. One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant argues (p 6) that Fukukawa relates to heating and imidization conditions, and therefore Fukukawa does not provide a basis for arriving at the presently recited TPP content range. However, this argument fails to establish nonobviousness because Fukukawa was not relied on to provide any basis for modifying TPP content.
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.
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/RACHEL KAHN/ Primary Examiner, Art Unit 1766
