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 12/18/2025.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/18/2025 has been entered.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.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 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).
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 1.5-4.0 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 considered to be 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), and exemplifies a polyimide film which has triphenyl phosphate in an amount of 2.0 wt% (example 2). The tensile strength and flexibility of the films are substantially improved relative to a comparative film with no phosphorus compound (see Table 1 in col 9).
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 the exemplified amount of 2.0 wt%, which falls within the presently claimed range of 1.5-4.0 wt%) in order to improve the mechanical properties of the film without causing undesired discoloration thereof.
As to the presently recited elastic modulus, surface roughness and bubble concentration “when the polyimide film has a thickness of 75 µm”:
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, and, which contains 2.0 wt % triphenyl phosphate.
Back and Maki are silent as to the recited properties.
Amended instant claim 1 limits the elastic modulus, surface roughness and bubble concentration of the polyimide film when the polyimide film has a thickness of 75 µm. The instant claims are not limited to a polyimide film having any particular thickness. That is, a polyimide film according to claim 1 is only required to satisfy the recited properties when the polyimide film has a thickness of 75 um. Therefore, a polyimide film comprising 1.5-4.0 wt% TPP which is obtained by imidizing a polyamic acid formed from the monomers recited in claim 1 (in mol percentages within the ranges recited in claim 1), and which does not meet the recited properties, falls within the scope of claim 1 as long as the film has a thickness other than 75 µm.
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, the 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 other than 75 µm.
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 1.5-4.0 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 considered to be 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), and exemplifies a polyimide film which has triphenyl phosphate in an amount of 2.0 wt% (example 2). The tensile strength and flexibility of the films are substantially improved relative to a comparative film with no phosphorus compound (see Table 1 in col 9).
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 (e.g., Maki’s exemplified 2.0 wt%) which falls within the presently claimed range of 1.5-4.0 wt%, in order to improve the mechanical properties of the film without causing undesired discoloration thereof.
As to the presently recited elastic modulus, surface roughness and bubble concentration “when the polyimide film has a thickness of 75 µm”:
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, and, which contains 1.5-4.0 wt % triphenyl phosphate.
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 1.5-4.0 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 1.5 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 1.5 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 range when a thickness thereof is 75 microns.
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 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 1.5-4.0 wt % triphenyl phosphate, by 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 12/18/2025 have been fully considered.
Applicant argues (pp 5-6) that Back and Maki do not disclose the recited physical properties associated with using TPP in a polyimide film, and therefore, it is not reasonable to assert that modified Back suggests a film which is substantially similar to the film of instant example 2. However, the finding that the cited prior art does not measure the same properties which Applicant has measured and recited in the instant claims is not sufficient to establish that the films of the cited prior art do not fall within the scope of the instant claims. Additionally, this argument is unpersuasive for at least the reason that the current rejections over Back in view of Maki do not assert that either Back or Maki individually disclose or suggest a film according to the present claims.
Applicant argues (p 6) that the instant examples show decreasing elastic modulus as TPP content increases. Applicant argues that this is in contrast to Maki’s teaching to improve tensile strength and bending life by adding TPP. However, Applicant has not explained how or why Maki’s teachings with regard to improving bending and tensile strength contrast with the instant data regarding elastic modulus. Therefore, Applicant’s argument is unpersuasive for at least the reason that Applicant has not established that there is contradiction or conflict between the data in Maki and the data in the instant specification. Moreover, Applicant may have recognized another advantage (decrease in bubble formation in a 75 micron thick film produced via a specific imidization method) which would flow naturally from following the suggestion of the prior art (see arguments on p 7). However, this cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
Conclusion
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/RACHEL KAHN/Primary Examiner, Art Unit 1766
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