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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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.
Claims 1, 3, 4 and 8-12 are pending as amended on 12/18/2025. Claims 3 and 4 stand withdrawn from consideration.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.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 and 8-11 are rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (JP 2009286706 A; machine translation cited herein) in view of Poe et al (US 2012/0190802) and Schork (Control of Polymerization Reactors, 1993, Marcel Dekker, p 52).
As to claims 1 and 11, Hasegawa discloses a polyimide film [0141] comprising a polyimide:
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Wherein X is a tetravalent cyclohexane group and A is a divalent group [0026-28], formed by reaction of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (CHTCA) [0033] with diamine [0066]. Hasegawa names several examples of diamine monomers in [0069].
The diamines named in [0069] include ether-containing diamines which have structures according to the presently recited “first” structural unit formula 3 (i.e., named diamines include 4,4’-diaminodiphenyl ether, 3,4’-diaminodiphenyl ether [instant diamine B-1], 1,3-bis(3-aminophenoxy)benzene [instant diamine B-2], 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene) [instant diamine B-3]. The diamines named in [0069] also include ether-containing diamines which have structures according to the presently recited “second” structural unit formulas 8 and 9 (i.e., named diamines include bis(4-(3-aminophenoxy)phenyl)sulfone [instant diamine B-4] and bis(4-(4-aminophenoxy)phenyl)sulfone) [instant diamine B-5], respectively). Hasegawa also exemplifies polyimides formed from reacting:
CHTCA with 1,4-bis(4-aminophenoxy)benzene (“TPE-Q”), Example 4, [0144] (TPE-Q has a structure according to instant formula 3 and is the same as instant diamine B-3);
CHTCA with 1,3-bis(4-aminophenoxy)benzene (“TPE-R”), Example 5 [0145] (TPE-R has a structure according to instant formula 3);
CHTCA with bis(4-(4-aminophenoxy)phenyl)sulfone (“BAPS”) Example 8, [0148] (BAPS has a structure according to instant formula 9 and is the same as instant diamine B-5).
Hasegawa teaches that the diamines may be used alone or in combination of two or more thereof [0069] (emphasis added). In Table 1 [0142], Hasegawa compares the properties of various polyimides which have the same dianhydride structure (CHTCA) and different diamine unit structures. Hasegawa’s examples show that changing the diamine monomer constituent of the polyimide results in changes in various thermal, optical and mechanical properties of the polyimide. However, Hasegawa does not exemplify a polyimide formed from a combination of two or more diamine monomers.
Poe provides a discussion which shows the general level of knowledge in the art regarding structure/property relationships in polyimides. Poe teaches that polyimides are a type of polymer with many desirable properties [0017], usually formed from a diamine monomer and a “diacid monomer” (which is defined to include a dianhydride) [0018]. Poe teaches that it is possible to mix different varieties of each type of monomer, such that two or more dianhydride monomers and two or more diamine monomers can be included in the reaction vessel. The monomer constituents of each polymer chain can be varied to produce polyimides with different properties [0020-21]; the characteristics or properties of the final polymer are significantly impacted by the choice of monomers which are used to produce the polymer [0026].
Schork teaches that the ability to create a macromolecule containing two or more types of monomer units gives the polymer chemist a greatly increased ability to custom design a polymer to yield specific end-use properties (p 52, first paragraph). Schork teaches that as a general rule, a copolymer from monomers A and B will have properties intermediate between those of the two homopolymers of A and B, with the percent of A units in the polymer determining whether the copolymer more nearly resembles homopolymer A or B. See 2.3.1 on p 52.
Considering the disclosures of Poe and Schork, the person having ordinary skill in the art would have been motivated to form a polyimide from two or more types of a dianhydride and/or diamine monomer in order to vary the properties of the resulting polyimide. The person having ordinary skill in the art would have been motivated to select appropriate comonomer structures, and appropriate amounts of each comonomer, depending on the desired balance of final characteristics or properties (including thermal, mechanical and optical properties) in the final polymer. It would have been obvious to the person having ordinary skill in the art, therefore, to have prepared a polyimide by reaction of CHTCA dianhydride with two or more diamines, as disclosed by Hasegawa, by selecting any appropriate combination of two or more diamines named by Hasegawa in [0069], including, e.g., a combination of 1,3-bis(3-aminophenoxy)benzene (corresponding to instant diamine “B-2” and according to instant formula 3), 1,4-bis(4-aminophenoxy)benzene (corresponding to instant diamine “B-3” and according to instant formula 3), bis(4-(3-aminophenoxy)phenyl)sulfone (corresponding to instant diamine “B-4” and according to instant formula 8), and bis(4-(4-aminophenoxy)phenyl)sulfone (corresponding to instant diamine “B-5” and according to instant formula 9), in order to produce a polyimide and polyimide film having a balance of the properties associated with each of the diamines within the combination, and suitable for the various types of applications taught by Hasegawa [0001]. Considering Schork, it would have been further obvious to the person having ordinary skill in the art to have selected any appropriate amount of each diamine comonomer in order to achieve the desired resemblance of the overall copolymer to any one homopolymer formed from each of the respective diamine comonomers, including diamine comonomer amounts such that the bis(aminophenoxy)benzene monomers (according to instant formula 3) and BAPS monomers (according to instant formulas 8 and 9) are in a 1:1 ratio, and further including amounts such that the meta-linked BAPS (according to instant formula 8) and para-linked BAPS (according to instant formula 9) are in a ratio within the instant range of 8:2 and 6:4.
As to claims 8 and 9, modified Hasegawa suggests a polyimide according to claim 1, as set forth above. Hasegawa discloses that the CHTCA monomer has extremely high polymerizability, and that the intrinsic viscosity of the polyamic acid precursor is 0.5-3.8 dL/g [0036]. Hasegawa teaches that the higher the intrinsic viscosity the better, preferably 1.0 dL/g or more, otherwise the film forming property is deteriorated and cracking of the cast film may occur [0078]. A sufficient degree of polymerization is also taught to be associated with a high enough molecular weight to achieve sufficient film toughness [0004, 0031]. Considering Hasegawa’s disclosure, the person having ordinary skill in the art would have been motivated to select an appropriately high intrinsic viscosity in order to ensure high molecular weight, and desired film forming property and toughness. It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a polyamic acid precursor having any intrinsic viscosity within Hasegawa’s disclosed range of 0.5-3.8 dL/g, including an intrinsic viscosity which corresponds to a polyimide intrinsic viscosity and polyimide molecular weight within the presently claimed ranges.
As to claim 10, modified Hasegawa suggests a polyimide according to claim 1, as set forth above. Hasegawa teaches that the glass transition temperature of the polyimide is preferably 230 C or higher when used as a display substrate [0110], which overlaps the presently claimed range of 200 to 400 C. It would have been obvious to the person having ordinary skill in the art to have formed a polyimide, as suggested by modified Hasegawa, having any Tg within Hasegawa’s disclosed range in order to ensure suitability as a display substrate, including a Tg within the presently claimed range. Case law has established that a prima facie case of obviousness is established where the claimed ranges overlap the ranges disclosed by the prior art. See MPEP 2144.05.
Claim(s) 12 is rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (JP 2009286706 A; machine translation cited herein) in view of Poe et al (US 20120190802) and Schork (Control of Polymerization Reactors, 1993, Marcel Dekker, p 52), and further in view of Hong et al (US 2020/0353668).
The rejection of claims 1 and 11 over Hasegawa in view of Poe and Schork is incorporated here by reference.
Hasegawa teaches a substrate for a display which may contain the polyimide, and which is excellent in transparency and flexibility [0109]. Hasegawa teaches that the light transmission in the 400 nm region, which is an indicator of clarity, is preferably at least 70%, and even more preferably 80% [0110]. However, Hasegawa fails to teach the yellow index at 70 micron or the light transmittance at 550 nm.
Like Hasegawa, Hong teaches a polyimide film which is advantageous for use as a substrate for various applications of flexible display devices [0015-16, 0099]. Hong discloses that if the yellowness (YI) is excessively high, the polyimide is limited in use as a display material [0032]. Hong teaches a film thickness of 25-150 microns [0056], a yellowness which is preferably 4.0 or less, and a light transmittance which is preferably 88% or more at 550 nm [0058]. Considering Hong’s disclosure, when forming a polyimide film intended for use as a display substrate material, one having ordinary skill in the art would have been motivated to form a film having any desired thickness within Hong’s disclosed range of 25-150 microns, and to target a yellowness index of 4.0 or less and a 550 nm light transmittance of 88% or more, in order to provide the properties (thickness, transparency and colorlessness) required for use as a display substrate. 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 Hasegawa, having any appropriate thickness within Hong’s range of 25-150 microns (including 70 microns), and having a yellow index and 550 nm transmittance within Hong’s disclosed ranges, thereby arriving at the presently claimed subject matter.
Response to Arguments
Applicant's arguments and Declaration under 37 CFR 1.132 filed 12/18/2025 have been fully considered.
In the remarks and Declaration filed on 12/18/2025, Applicant argues (pp 6-7) that the polyimides of instant examples 19 and 20 [which are representative of the claimed subject matter in that they are polyimides formed from CHTCA as dianhydride and a combination of diamines according to “first” unit formula 3 (B-2 and B-3), a diamine according to “second” unit formula 8 (B-4) and a diamine according to “second” unit formula 9 (B-5)] exhibit a lower yellow index than the polyimides of examples 7-10, which include only “first” unit diamines (B-2 and B-3).
However, comparing the claimed polyimides of instant examples 19 and 20 (formed from CHTCA and diamines B-2, B-3, B-4 and B-5) to:
Comparative copolyimides of instant examples 8 and 9 (formed from CHTCA and diamines B-2 and B-3),
Comparative copolyimides of instant examples 12 and 13 (formed from CHTCA and diamines B-4 and B-5), and
Comparative homopolyimides of instant examples 2-5 (formed from CHTCA and each of diamines B-2 through B-5 individually)
demonstrates that polyimides formed from a combination of “first unit” and “second unit” diamines have a yellow index property which is intermediate between copolyimides and homopolyimides formed from only “first unit” diamines and polyimides formed from only “second unit” diamines. Applicant has not explained why it would have been unexpected to one having ordinary skill in the art to find that the yellow index of a polyimide formed from copolymerizing CHTCA and a combination of four diamine monomers (i.e., a polyimide of instant examples 19 and 20) falls intermediate between the yellow index properties of copolyimides formed from polymerizing CHTCA with subsets of diamine monomers (such as between the yellow indices of polyimides of examples 8 and 9 and polyimides of examples 12 and 13) or single diamine monomers (see yellow indices of homopolyimides of examples 2-5) within the diamine combination. Because Applicant has not shown that the optical properties of a polyimide formed from the claimed diamine combination differ from the properties which would have been expected (based on the properties of polyimides formed from individual or subsets of diamines within the claimed combination), Applicant’s showing that examples 19 and 20 have a lower yellow index than examples 7-10 fails to overcome the rejections of record.
Applicant similarly argues (pp 7-8) that examples 19-20 exhibit improved mechanical properties compared to examples 11 to 14, which include only the second structural unit. However, as with the discussion of optical properties above, a comparison of instant examples 19-20 to instant examples 11-14 to instant examples 7-10 demonstrates that polyimides formed from a combination of “first unit” and “second unit” diamines (Ex 19-20) have mechanical properties which are intermediate between copolyimides and homopolyimides formed from only “first unit” diamines (the mechanical properties of Ex 7-10 are superior to Ex 19-20) and polyimides formed from only “second unit” diamines (the mechanical properties formed from Ex 11-14 are inferior to Ex 19-20). Because Applicant has not shown that the mechanical properties of a polyimide formed from the claimed diamine combination differ from the properties which would have been expected (based on the properties of polyimides formed from individual or subsets of diamines within the claimed combination), Applicant’s showing that examples 19 and 20 have a improved mechanical properties compared to examples 11-14 fails to overcome the rejections of record.
Applicant argues (pp 8-9 and pp 12-13) that the cited prior art references do not disclose a PI containing the presently recited first and second structural units, they merely disclose that two or more diamines may be used. However, Applicant’s argument fails to overcome the rejections of record, because the rejections do not assert that any one reference anticipates the claimed PI, and motivation to utilize a combination of diamines named in the prior art (see teachings in Poe, Schork regarding utilizing combinations of monomers to form copolymers in order to achieve a desired balance in properties) is established in the rejection of record.
Applicant argues (pp 9-11) that additional experiments (see also Declaration filed 12/18/2025) show that polyimides having a molar ratio of formula 8 to formula 9 units within a range of 8:2 to 6:4 exhibit a lower yellow index than comparative examples with molar ratios outside the claimed range. However, the additional examples appear to show that copolyimides having higher contents of formula 8 units (i.e., B-4 diamine units) have lower yellow indices than copolyimides having higher contents of formula 9 units (i.e., B-5 diamine units). Given that a homopolyimide formed from B-4 diamine has a YI of 2.21 (see instant example 4) while a homopolyimide formed from B-5 diamine has a YI of 3.91 (see instant example 5), it is not unsurprising to find that yellowness index generally decreases as the ratio of B-4 diamine relative to B-5 diamine within a copolyimide increases. This trend can also be observed in instant examples 11-14: as B-4 content increases relative to B-5 content, YI decreases. Given that the yellowness index of the additional comparative examples shown in Table B follows an expected trend corresponding to B-4 content relative to B-5 content, the additional examples fail to establish that there is criticality associated with the presently claimed B-4:B-5 molar ratio range.
Applicant similarly argues (pp 11-12) that additional experiments (see also Declaration p 4, bottom) show that polyimides having a molar ratio of formula 8 to formula 9 units within a range of 8:2 to 6:4 exhibit improved thermal stability relative to comparative examples with molar ratios outside the claimed range. However, the additional examples appear to follow a general trend: as the content of formula 8 units (i.e., B-4 diamine units) within the copolyimides increases relative to the content of formula 9 (B-5 diamine) units, the thermal decomposition temperature increases, the wtr600 percentage increases, and CTE value decreases. Applicant has not explained how the properties of polyimides having a ratio of B-4 to B-5 units within the claimed range differ from the expected trend in properties resulting from combining two different monomers in varying amounts, and therefore, Applicant has not established that the thermal properties of the additional examples demonstrate criticality associated with the presently claimed B-4:B-5 molar ratio range.
Conclusion
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/RACHEL KAHN/ Primary Examiner, Art Unit 1766