Polyimide, resin composition, polyimide film and method thereof

Abstract

The present invention provides a resin composition comprising: a polyamide-amide copolymer containing a structural unit L represented by the following general formula (1) and having a structure represented by the following general formula (A-1) as X 2 in general formula (1); an organic solvent; and an amide catalyst selected from at least one of the group consisting of pyridine, triethylamine, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole and N-tert-butoxycarbonylimidazole (N-Boc-imidazole); {wherein, X 1 to X 4, n, m, l, R 1 to R 2, a to b and *as defined in the specification}.

Description

Technical Field

[0001] The present invention relates to a polyamide-imide, for example, for manufacturing a substrate for a flexible device, and a resin composition containing the same, a polyimide resin film, a resin film, and a manufacturing method thereof. Prior Art

[0002] Polyimide resin films are usually used as resin films in applications requiring high heat resistance. Common polyimide resins are made by solution polymerization of aromatic carboxylic acid dianhydrides and aromatic diamines to produce polyimide precursors, which are then thermally imidized at high temperatures or chemically imidized using a catalyst to produce high heat-resistant resins.

[0003] Polyimide resin is an insoluble, infusible, super heat-resistant resin with excellent properties such as thermal oxidation resistance, heat resistance, radiation resistance, low temperature resistance, and chemical resistance. Therefore, polyimide resin can be used in a wide range of fields including electronic materials. Examples of the application of polyimide resin in the field of electronic materials include: insulating coating materials, insulating films, semiconductors, and electrode protective films for thin-film transistor liquid crystal displays (TFT-LCDs). Recently, research is being conducted on the use of polyimide resin as a flexible substrate that takes advantage of its light weight and softness to replace the glass substrate that has been used in the field of display materials.

[0004] When polyimide resin is used as a flexible substrate, the following steps are widely used: for example, a varnish containing polyimide resin or its precursor and other components is applied to a suitable support such as a glass substrate, dried to form a film, and then the film is peeled off from the glass substrate after forming components, circuits, etc. on the film. However, when manufacturing a laminate having polyimide resin, a heat treatment at a high temperature of 250°C or more is required in order to dry and imidize the polyimide precursor. The heat treatment causes residual stress in the laminate, resulting in serious problems such as warping and peeling. The reason for this is that the linear expansion coefficient of polyimide is larger than that of the material constituting the support.

[0005] In order to reduce the residual stress of the above-mentioned laminate, the use of polyimide resins with a thermal expansion coefficient as small as that of glass is being studied. As a polyimide material with a relatively small thermal expansion coefficient, the most well-known one is a polyimide containing 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter also referred to as BPDA) and p-phenylenediamine. Although the thermal expansion coefficient of the polyimide material depends on the film thickness and production conditions, it is reported that the polyimide shows a very low linear thermal expansion coefficient (Non-Patent Document 1).

[0006] However, ordinary polyimide resins including the polyimide described in the above document are colored brown or yellow due to their high electron density, so the transmittance in the visible light region is low, and it is difficult to achieve a sufficiently low yellowness (YI value) for use in fields requiring transparency. In addition, it is known that polyimide with a low linear expansion coefficient generally has a high molecular orientation, so the laminate is prone to turbidity and stains, resulting in poor transmittance (Patent Document 2).

[0007] Generally, regarding yellowness (YI value), it is known that, for example, a solvent-soluble polyimide using a diamine having a trifluoromethyl group or a polyimide using an alicyclic tetracarboxylic dianhydride or diamine exhibits extremely low yellowness (YI value) and residual stress (Patent Documents 3 and 4). [Prior Technical Literature] [Patent Document]

[0008] [Patent Document 1] International Publication No. 2005 / 113647 [Patent Document 2] Japanese Patent No. 6443579 [Patent Document 3] International Publication No. 2019 / 211972 [Patent Document 4] International Publication No. 2020 / 138360 [Patent Document 5] Japanese Patent No. 4303623 [Patent Document 6] Japanese Patent No. 5595381 [Patent Document 7] Japanese Patent No. 6073528 [Patent Document 8] Japanese Patent Publication No. 63-101424 [Patent Document 9] Japanese Patent Publication No. 63-110219 [Non-patent literature]

[0009] [Non-patent document 1] "Latest Polyimide - Fundamentals and Applications -", edited by the Japan Polyimide Research Association Summary of the invention

[0010] [Problems that the invention aims to solve] As described above, in order to use polyimide resin as a colorless, transparent, flexible substrate, it is required to simultaneously achieve two contradictory properties: excellent thermal properties and transparency. In particular, as the device type of TFT has recently changed to LTPS (low temperature polycrystalline silicon), it is expected that a polyimide resin with excellent transparency even in a thermal history higher than the previous level will be developed.

[0011] The polyimide resin described in Patent Document 1, which is a common polyimide, has a relatively low linear thermal expansion coefficient, but has insufficient transparency when used in an LTPS step at 400°C or higher. In addition, although it is reported that the polyimide described in Patent Document 2 has excellent linear expansion coefficient (hereinafter also referred to as "CTE") and transparency by using specific tetracarboxylic dianhydride and diamine, the laminated body will become cloudy and stained during heating at 400°C or higher, and the haze (hereinafter also referred to as "HAZE value") is insufficient when used as a transparent substrate.

[0012] Furthermore, as a known technical concept, in order to achieve transparency, as described in Patent Document 3, it is known that intramolecular charge transfer (CT) migration is suppressed by using alicyclic acid dianhydrides or diamines without aromatic rings or using diamines having functional groups that cause bulky intramolecular twisting (e.g., 2,2'-bis(trifluoromethyl)benzidine, hereinafter also referred to as TFMB). However, these polyimides with excellent transparency have insufficient heat resistance and thermal properties in the state of polyamide acid. In order to obtain higher transparency, it is necessary to prepare a solvent-soluble polyimide resin that has been imidized during solution polymerization. However, these polyimides have a large linear expansion coefficient when made into a film, lack thermal stability in a high temperature range of 430°C or above, and are not sufficiently soluble in solvents.

[0013] In order to simultaneously achieve these opposite properties, namely thermal properties and transparency, the mixing or copolymerization of polyimide and polyamide is being studied, but it is known that even if these resins are simply mixed, phase separation will occur during the molding process, and they are not suitable as transparent substrates (Patent Document 5). The reason is that heat-resistant polyimide has a highly planar and rigid skeleton, so it is not easy to dissolve with soluble polyimide with a curved group during film formation, resulting in phase separation.

[0014] Patent document 4 discloses that by allowing an imide structure and an amide structure to coexist locally in a molecule, storage stability and molding processability can be improved. However, the present inventors and others have confirmed that the polyamide-imide resin composition described in Patent document 4 lacks heat resistance, and the yellowness (YI value) and haze (HAZE) are significantly deteriorated in the heat history of 430°C or above in the LTPS step. The main reason is that the monomer skeletons of polyimide and polyamide are common. The higher the ratio of the common monomer skeletons in polyimide and polyamide, the more it can suppress the generation of haze caused by phase separation, but on the other hand, it is more difficult to achieve the opposite characteristics of thermal properties and transparency at the same time.

[0015] In addition, Patent Document 6 discloses that by allowing the coexistence of an imide structure and an amido acid structure in the molecule and using an alicyclic diamine, the bending resistance and transparency can be improved. However, the inventors and others have confirmed that the yellowness (YI value) and haze (HAZE) of the block polyimide described in Patent Document 6 are significantly deteriorated in the heat history of 430°C or above in the LTPS step. The main reason is that an alicyclic diamine is used as the diamine, and the alicyclic diamine has excellent bending resistance, but on the other hand, the alicyclic decomposition will occur in the heat history of 430°C or above, making it difficult to achieve both heat resistance and bending resistance.

[0016] Furthermore, the conventional polyimide resins containing polyimide described in the above-mentioned Patent Documents 7 to 9 are colored brown or yellow due to their high electron density, and thus have low light transmittance in the visible light region, and are therefore difficult to use in fields requiring transparency. Furthermore, it was found that when a polyimide resin film was formed using a conventional resin composition, the fluidity of the resin composition was insufficient during the curing step (heating to about 400° C.), and the in-plane uniformity of the film thickness of the obtained polyimide resin film was insufficient. Thus, conventional polyimide resin films are insufficient in properties required for use as colorless transparent substrates for displays, such as in-plane uniformity of film thickness and yellowness (YI value).

[0017] The present invention has been made in view of the above situation and in order to solve the above-mentioned problems. The object of the present invention is to provide a polyamide-imide copolymer resin composition which realizes both transparency and heat resistance by copolymerizing a polyamide having excellent thermal characteristics and having an aromatic ester diamine as a main component with a polyimide block having excellent transparency, or a polyamide-imide copolymer resin composition which realizes both transparency and heat resistance and further has bending resistance by copolymerizing a polyimide having excellent bending resistance and transparency with a polyamide block having excellent heat resistance, and a composition comprising the polyamide-imide copolymer resin composition having the aromatic ester diamine as a main component. A resin composition of polyimide or polyimide copolymer using the same, or a resin composition of polyamide or polyamide-imide copolymer using 4-aminobenzoic acid 4-amino-3-fluorophenyl ester (APAB) that can reduce defects of polyimide film during infrared (IR) curing, or a resin composition or polyimide resin film that can obtain a polyimide resin film with excellent in-plane uniformity of film thickness and low yellowness (YI value), as well as a method for manufacturing the same, a method for manufacturing a display, a method for manufacturing a laminate, and a method for manufacturing a flexible device. [Technical means to solve the problem]

[0018] The inventors have conducted intensive research and repeated experiments to solve the above problems. As a result, they found that the polyimide film obtained by curing a resin composition containing a polyamide-imide copolymer having a specific structure has excellent transparency, haze, heat resistance, and linear expansion coefficient, has low residual stress and bending resistance, or the defects of the polyimide film during infrared (IR) curing are reduced, and / or by including a non-protonic polar substance with a boiling point of 250°C to 350°C in the resin composition, the resin becomes soft and has fluidity, and when the polyimide resin film is prepared, the in-plane uniformity of the film thickness is improved, and the YI can also be reduced. Based on these findings, the present invention was completed. That is, the invention is as follows.

[0019] <1> A resin composition characterized by comprising a polyamide-imide copolymer, (d) an organic solvent, and (e) an imidization catalyst, wherein the (e) imidization catalyst is at least one selected from the group consisting of an imidazole compound, a pyridine compound, and a tertiary amine compound. The polyamide-imide copolymer comprises a structural unit represented by the following general formula (1): [Chemistry 1] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n, m, and l are positive integers, and Contains the following general formula (A-1): [Chemistry 2] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented is used as X2} in the above general formula (1). <2> The resin composition of item 1, wherein the imidazole compound is at least one selected from the group consisting of 1-methylimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), 2-methylimidazole, 2-phenylimidazole, benzimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 4-methyl-2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1H-imidazole, and 1,2-dimethylimidazole, The pyridine compound is at least one selected from the group consisting of 4-dimethylaminopyridine, 2,2'-bipyridine, nicotinic acid, isoquinoline, pyridine, and 2-methylpyridine, and / or The tertiary amine compound is at least one selected from the group consisting of 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and triethylamine. <3> The resin composition of item 1 or 2, wherein the above-mentioned (e) imidization catalyst is the above-mentioned imidazole compound. <4> The resin composition of any one of items 1 to 3, wherein the content of the above-mentioned (e) imidization catalyst is 5 parts by mass or more relative to 100 parts by mass of the above-mentioned polyamide-imide copolymer. <5> A resin composition comprising a polyamide-imide copolymer and (d) an organic solvent. The polyamide-imide copolymer comprises a structural unit represented by the following general formula (1): [Chemistry 3] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n, m, and l are positive integers, and Contains the following general formula (A-1): [Chemistry 4] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented by is X2} in the above general formula (1), and The weight average molecular weight of the polyamide-imide copolymer is greater than 170,000. <6> The resin composition of any one of items 1 to 4, wherein the weight average molecular weight of the polyamide-imide copolymer is greater than 170,000. <7> A resin composition comprising polyamide, (d) an organic solvent, and (e) an imidization catalyst. The polyamine comprises a structural unit represented by the following general formula (3): [Chemistry 5] {wherein, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer, and Contains the following general formula (A-1): [Chemistry 6] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented by is X2} in the above general formula (3), The (e) imidization catalyst is at least one selected from the group consisting of 1-methylimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), 2-methylimidazole, 2-phenylimidazole, benzimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 4-methyl-2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1H-imidazole, 4-dimethylaminopyridine, 2,2'-bipyridine, nicotinic acid, isoquinoline, pyridine, 2-methylpyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and triethylamine. <8> A resin composition comprising polyamide, (d) an organic solvent, and (e) an imidization catalyst. The polyamine comprises a structural unit represented by the following general formula (3): [Chemistry 7] {wherein, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer, and Contains the following general formula (A-1): [Chemistry 8] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented by is X2} in the above general formula (3), The (e) imidization catalyst is an imidazole compound, and the content of the (e) imidization catalyst is 5 parts by mass or more relative to 100 parts by mass of the polyamine. <9> A resin composition comprising polyamide, (d) an organic solvent, and (e) an imidization catalyst. The polyamine comprises a structural unit represented by the following general formula (3): [Chemistry 9] {wherein, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer, and Contains the following general formula (A-1): [Chemistry 10] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented by is X2} in the above general formula (3), The above-mentioned (e) imidization catalyst is an imidazole compound, and The weight average molecular weight of the polyamine is greater than 170,000. <10> The resin composition of item 7 or 8, wherein the weight average molecular weight of the polyamine is greater than 170,000. <11> The resin composition of any one of items 1 to 10, wherein the content of the imidization catalyst (e) is 10 parts by mass or more relative to 100 parts by mass of the polyamide-imide copolymer or 100 parts by mass of the polyamide. <12> The resin composition of any one of items 1 to 11, wherein the above-mentioned (e) imidization catalyst is an imidazole compound comprising N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and / or 1-methylimidazole. <13> A resin composition as in any one of items 1 to 12, wherein the weight average molecular weight of the polyamide-imide copolymer or the polyamide is greater than 220,000. <14> The resin composition of any one of items 1 to 13 further comprises a non-protonic polar substance with a boiling point of 250° C. to 350° C. <15> The resin composition of item 14, wherein the aprotic polar substance is cyclobutane sulfonate. <16> The resin composition of any one of items 1 to 15, wherein X4 in the above general formula (1) or X2 in (3) is selected from the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6): [Chemistry 11] {wherein, R 8 to R 11 each independently represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, and h to k each independently represent an integer of 0 to 4, Z 2 represents a bonding group, and * represents a bonding portion} [Chemistry 12] {wherein, R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, l and m each independently represent an integer of 0 to 4, and * represents a bonding portion} [Chemistry 13] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion} At least one of the groups of structures represented. <17> The resin composition of any one of items 1 to 6 and 11 to 16, wherein X3 in the above general formula (1) is selected from the following general formula (A-3): [Chemistry 14] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the structures represented by the present invention, a structure derived from 4,4'-oxydiphthalic anhydride (ODPA), a structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), a structure derived from biphenyltetracarboxylic anhydride (BPDA), and a structure derived from 4,4'-biphenylbis(trimellitic acid monoester anhydride) (TAHQ). <18> The resin composition of any one of items 1 to 6 and 11 to 17, wherein the content of the above-mentioned (e) imidization catalyst is in the range of 0.02-0.15 mol% relative to 1 mol of the repeating unit of the above-mentioned polyamide-imide copolymer. <19> A polyamide-imide copolymer, characterized in that it comprises a structural unit L represented by the following general formula (1): [Chemistry 15] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n, m, and l are positive integers, the structural unit containing X1 and X2 is referred to as structural unit N, and the structural unit containing X3 and X4 is referred to as structural unit M, When X2 is derived from 4-aminobenzoic acid 4-amino-3-fluorophenyl ester, the following structures 1 and 2 are excluded: 1. When X3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), X2 is a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine; and 2. X3 is a radical derived from norfloxacin-2-spiro-α-cyclopentanone-α'-spiro-2''-norfloxacin-5,5'',6,6''-tetracarboxylic dianhydride;}, and Has the following general formula (A-1): [Chemistry 16] {wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion} Or the following general formula (A-2): [Chemistry 17] {wherein, R 3 represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, and c is an integer of 0 to 4. * represents a bonding portion} The structure represented is used as the above-mentioned X2. <20> The polyamide-imide copolymer of item 19, wherein X3 in the above general formula (1) is selected from the following general formula (A-3): [Chemistry 18] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the group consisting of the structure represented by, the structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). <21> The polyamide-imide copolymer of item 19 or 20, wherein X4 in the above general formula (1) is selected from the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6): [Chemistry 19] {wherein, R 8 to R 11 each independently represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, and h to k each independently represent an integer of 0 to 4, Z 2 represents a bonding group, and * represents a bonding portion} [Chemistry 20] {wherein, R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, l and m each independently represent an integer of 0 to 4, and * represents a bonding portion, except when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), the general formula (A-5) is a group derived from 4,4'-diaminodiphenylsulfonium} [Chemistry 21] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion} At least one of the groups of structures represented. <22> A polyamide-imide copolymer, characterized in that it comprises a structural unit L represented by the following general formula (1): [Chemistry 22] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n, m, and l are positive integers, the structural unit containing X1 and X2 is referred to as structural unit N, and the structural unit containing X3 and X4 is referred to as structural unit M, and X4 is excluding a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine}, and Has a general formula (A-3) selected from the following: [Chemistry 23] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the structures represented by, a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and a structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) is used as X3. <23> The polyamide-imide copolymer of item 22, wherein X4 in the above general formula (1) is selected from the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6): [Chemistry 24] {wherein, R 8 to R 11 each independently represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, and h to k each independently represent an integer of 0 to 4, Z 2 represents a bonding group, and * represents a bonding portion} [Chemistry 25] {wherein, R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, i and j each independently represent an integer of 0 to 4, and * represents a bonding portion, except when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), the general formula (A-5) is a group derived from 4,4'-diaminodiphenylsulfonium} [Chemistry 26] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion} At least one of the groups of structures represented. <24> The polyamide-imide copolymer according to any one of items 19 to 23, wherein the diamine component constituting X2 in the general formula (1) is different from the diamine component constituting X4 in terms of diamine composition or diamine type. <25> The polyamide-imide copolymer of any one of items 19 to 24, wherein X1 in the general formula (1) is at least one selected from the group consisting of a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and a structure derived from 4,4'-biphenyl bis(trimellitic acid monoester anhydride) (TAHQ). <26> The polyamide-imide copolymer according to any one of items 19 to 25, wherein the molar ratio of X1 to X2 (X2 / X1) contained in the general formula (1) is 0.84-1.00, and the molar ratio of X3 to X4 (X4 / X3) contained in the general formula (1) is 1.01-2.00. <27> The polyamide-imide copolymer of any one of items 19 to 26, wherein the molar ratio of the structural unit N of the polyamide comprising X1 and X2 in the general formula (1) to the structural unit M of the polyimide comprising X3 and X4 (the molar number of the structural unit N: the molar number of the structural unit M) is in the range of 60:40 to 95:5. <28> A resin composition comprising the polyamide-imide copolymer as described in any one of items 19 to 27, and (d) an organic solvent. <29> The resin composition of item 28, wherein the ratio of the structural unit N of the polyamide containing X1 and X2 in all the polymers contained in the above-mentioned resin composition is 60-95 mol%. <30> The resin composition of item 28 or 29 further comprises (e) an imidization catalyst. <31> A polyimide copolymer, characterized by comprising a structural unit represented by the following general formula (2): [Chemistry 27] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, and n and m are positive integers, the structural unit containing X1 and X2 is referred to as structural unit N, and the structural unit containing X3 and X4 is referred to as structural unit M, and When X2 is derived from 4-aminobenzoic acid 4-amino-3-fluorophenyl ester, the following structures 1 and 2 are excluded: 1. When X3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), X2 is a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine; and 2. X3 is a radical derived from norfloxacin-2-spiro-α-cyclopentanone, α-α'-spiro-2''-norfloxacin-5,5'',6,6''-tetracarboxylic dianhydride}, and Has the following general formula (A-1): [Chemistry 28] {wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion} Or the following general formula (A-2): [Chemistry 29] {wherein, R 3 represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, c is an integer of 0 to 4, and * represents a bonding portion} The structure represented is used as the above-mentioned X2. <32> The polyimide copolymer of item 31, wherein X3 in the above general formula (2) is selected from the following general formula (A-3): [Chemistry 30] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the group consisting of the structure represented by, the structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). <33> A polyimide copolymer characterized by having a structural unit represented by the following general formula (2): [Chemistry 31] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n and m are positive integers, the structural unit containing X1 and X2 is referred to as structural unit N, and the structural unit containing X3 and X4 is referred to as structural unit M, and X4 is excluding a group derived from 4,4'-diaminodiphenylsulfone or 2,2'-bis(trifluoromethyl)benzidine}, and It comprises a compound selected from the following general formula (A-3): {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the structures represented by, a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and a structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) is used as X3. <34> The polyimide copolymer of item 33, wherein X4 in the above general formula (2) is selected from the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6): [Chemistry 32] {wherein, R 8 to R 11 each independently represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, and h to k each independently represent an integer of 0 to 4, Z 2 represents a bonding group, and * represents a bonding portion} [Chemistry 33] {wherein, R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, l and m each independently represent an integer of 0 to 4, and * represents a bonding portion, except when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), and when the general formula (A-5) is a group derived from 4,4'-diaminodiphenylsulfonium} [Chemistry 34] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion} At least one of the groups of structures represented. <35> A polyimide copolymer as described in any one of items 31 to 34, wherein X1 in the general formula (2) is at least one selected from the group consisting of a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and a structure derived from 4,4'-biphenyl bis(trimellitic acid monoester anhydride) (TAHQ). <36> The polyimide copolymer according to any one of items 31 to 35, wherein the molar ratio of X1 to X2 (X2 / X1) contained in the general formula (2) is 0.84-1.00, and the molar ratio of X3 to X4 (X4 / X3) contained in the general formula (2) is 1.01-2.00. <37> The polyimide copolymer of any one of items 31 to 36, wherein the molar ratio of the structural unit N of the polyimide comprising X1 and X2 in the general formula (2) to the structural unit M of the polyimide comprising X3 and X4 (the molar number of the structural unit N: the molar number of the structural unit M) is in the range of 60:40 to 95:5. <38> A resin composition, characterized in that: it has a polyimide precursor represented by the following general formula (I), or a polyimide precursor skeleton represented by the following general formula (I) and a polyimide skeleton represented by the following general formula (II), and Contains non-protonic polar substances with boiling points of 250℃~350℃, [Chemistry 35] {wherein, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer} [Chemistry 36] {wherein, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer}. <39> A resin composition comprising a polyimide represented by the following general formula (II), a solvent, and a non-protonic polar substance with a boiling point of 250° C. to 350° C.: [Chemistry 37] {wherein, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer}. [Effects of the Invention]

[0020] According to the present invention, a polyamide-imide copolymer that achieves both transparency and heat resistance, and a resin composition containing the same can be provided, and further a polyimide film having excellent transparency, haze, heat resistance and linear expansion coefficient, and a method for producing the same can be provided, and / or a polyimide having excellent bending resistance and transparency and an aromatic acid dianhydride having a fluorene skeleton as a main component and a polyamide block having excellent heat resistance can be provided, and further a polyamide-imide copolymer resin composition that achieves both transparency and heat resistance and further low residual stress and bending resistance, a polyimide, or a polyimide film, and a method for producing the same can be provided. Furthermore, a resin composition containing polyamide or polyamide-imide copolymer using 4-aminobenzoic acid 4-amino-3-fluorophenyl ester (APAB) which can reduce defects of polyimide film during infrared (IR) curing can be provided, and a polyimide film with reduced defects and a method for producing the same can also be provided. Furthermore, according to the present invention, a resin composition which can obtain a polyimide resin film having excellent in-plane uniformity of film thickness and low yellowness (YI value), a method for producing a polyimide resin film, a method for producing a display, a method for producing a laminate, and a method for producing a flexible device can be provided. Simple diagram description

[0021] FIG. 1 is a schematic diagram showing a structure of a top-emission type flexible organic EL (Electroluminescence) display as an example of a display according to an embodiment of the present invention, which is located above a polyimide substrate. Implementation

[0022] Hereinafter, the exemplary embodiments of the present invention (hereinafter, referred to as "embodiments") are described in detail. Furthermore, the present invention is not limited to the following embodiments, and can be implemented after various changes within the scope of its purpose. In addition, the characteristic values described in the present invention, unless otherwise specified, mean the values measured by the method described in the [Examples] or the method that the industry understands to be equivalent thereto.

[0023] <Resin composition> The resin composition provided in one aspect of the present invention comprises (a) polyamine and / or (b) polyimide, (c) polyamine-imide copolymer, polyimide or polyamine, and (d) organic solvent, and may also contain other components such as (e) imidization catalyst as needed.

[0024] Below, each component is described in order.

[0025] <First Embodiment> (A) Polyamide-imide copolymer The first embodiment of the present invention provides a polyamide-imide copolymer, characterized in that it comprises a structural unit L represented by the following general formula (1): [Chemistry 38] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, n, m, and l are positive integers, the structural unit containing X1 and X2 is referred to as structural unit N, and the structural unit containing X3 and X4 is referred to as structural unit M} And has the following general formula (A-1): [Chemistry 39] {wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion} Or the following general formula (A-2): [Chemistry 40] {wherein, R 3 represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, c is an integer of 0 to 4, and * represents a bonding portion} The structure represented is taken as X2.

[0026] Furthermore, as a specific example of the structure represented by the general formula (A-2), the following general formula (A-2a) can be cited: [Chemistry 41] {wherein, R 3, c and * are as defined in the general formula (A-2)}.

[0027] The polyamide-imide copolymer of the first embodiment can be used as a polyimide precursor. When the polyimide film is formed using the polyamide-imide copolymer, the linear expansion coefficient is low, the residual stress is low, and the haze (Haze value) and yellowness (YI value) are small. In addition, when the polyamide-imide copolymer of the first embodiment is used to form a polyimide film, the yellowness (YI value) in the high temperature region is small, and the haze (Haze value) is small. From this point of view, it is preferred that the weight average molecular weight of the polyamide-imide copolymer of the first embodiment is 170,000 or more, and / or it is preferred that when X2 is derived from a group of 4-aminobenzoic acid 4-amino-3-fluorophenyl ester, the following structures 1 and 2 are excluded: Configuration 1. When X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), X 2 is a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine; and The constituent 2.X 3 is a group derived from norfloxacin-2-spiro-α-cyclopentanone-α'-spiro-2''-norfloxacin-5,5'',6,6''-tetracarboxylic dianhydride.

[0028] <Second Embodiment> The second embodiment of the present invention provides a polyamide-imide copolymer, characterized in that it comprises a structural unit L represented by the above general formula (1) and comprises a compound selected from the following general formula (A-3): [Chemistry 42] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} At least one of the group consisting of the structure represented by, the structure derived from 4,4'-oxydiphthalic anhydride (ODPA), the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), the structure derived from biphenyltetracarboxylic anhydride (BPDA), and the structure derived from 4,4'-biphenylbis(trimellitic acid monoester anhydride) (TAHQ) is used as X1 and / or X3.

[0029] When the polyamide-imide precursor of the second embodiment is made into a polyimide film, the linear expansion coefficient is low, the residual stress is low, the bending resistance is excellent, and the haze (Haze value) and yellowness (YI value) are small. In addition, when the polyamide-imide copolymer of the second embodiment is made into a polyimide film, the yellowness (YI value) in the high temperature region is small and the haze (Haze value) is small. In the second embodiment, from this viewpoint, it is preferred that at least one selected from the group consisting of a structure represented by the general formula (A-3), a structure derived from ODPA, and a structure derived from 6FDA is included as X3, and / or when X3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorinated anhydride (BPAF), X4 is preferably excluding a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine.

[0030] <Third Embodiment> In a third embodiment of the present invention, the resin composition is characterized in that it has a polyimide precursor represented by the following general formula (I), or a polyimide precursor skeleton represented by the following general formula (I) and a polyimide skeleton represented by the following general formula (II), and contains a non-protonic polar substance with a boiling point of 250°C to 350°C, or the resin composition is characterized in that it contains a polyimide represented by the following general formula (II), a solvent, and a non-protonic polar substance with a boiling point of 250°C to 350°C. (Polyimide Precursor) [Chemistry 43] {wherein, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer}. (Polyimide resin) [Chemistry 44] {wherein, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer}.

[0031] The polyimide of the third embodiment is obtained by thermal imidization of a polyimide precursor, or chemical imidization. From the perspective of the transparency of the obtained polyimide film, thermal imidization is preferred. In addition, the resin composition may contain an imidization accelerator.

[0032] The resin composition of the third embodiment contains a non-protonic polar substance with a boiling point of 250°C to 350°C. In the curing step (heating step), the non-protonic polar substance plays a role as a plasticizer at a high temperature of, for example, 250°C or above, so that the resin becomes soft and has fluidity. When a polyimide resin film (hereinafter also referred to as a polyimide film) is made, the in-plane uniformity of the film thickness can be improved and the YI can also be reduced.

[0033] Furthermore, the resin composition of the third embodiment may further contain a solvent, such as an aprotic solvent. The aprotic solvent should be distinguished from the aprotic polar substance having a boiling point of 250° C. to 350° C.

[0034] Here, the P2 groups in the general formula (I) and (II) are acid anhydride residues, which may be the same or different. In addition, the P1 groups in the general formula (I) and (II) are diamine residues, which may be the same or different.

[0035] <Fourth Embodiment> (B) Polyamine In a fourth embodiment of the present invention, a polyamide or a polyamide-amide copolymer comprising a structural unit derived therefrom is provided, wherein the polyamide is characterized in that it comprises a structural unit represented by the following general formula (3): [Chemistry 45] {wherein, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer, and Has the following general formula (A-1): [Chemistry 46] (wherein, R1 and R2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion) The structure represented by is X2} in the above general formula (3), and The polyamide is formulated with a specific (e) imidization catalyst or the weight average molecular weight of the polyamide is 170,000 or more. The polyamide or the polyamide-imide copolymer containing the structural unit derived therefrom of the fourth embodiment can reduce defects of the polyimide film during infrared (IR) curing.

[0036] The features of the first, second, third and fourth embodiments can be combined or interchanged. The first, second, third and fourth embodiments are common structures, and the preferred structures are described below.

[0037] (a) <Embodiment of the polyamine portion> The polyamide portion constituting the polyamide-imide copolymer of the present invention is the portion represented by the structural unit N in the above general formula (1).

[0038] In the above general formula (1), X1 is a tetravalent organic group, and the plurality of X1 present in the polyimide precursor may be the same or different from each other. Examples of X1 include tetravalent organic groups derived from the following tetracarboxylic dianhydride.

[0039] Examples of the tetracarboxylic dianhydride include aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms, aliphatic tetracarboxylic dianhydrides having 6 to 50 carbon atoms, and alicyclic tetracarboxylic dianhydrides having 6 to 36 carbon atoms. Among these, from the viewpoint of yellowness in a high temperature range, aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms are preferred. The carbon number mentioned here also includes the number of carbon atoms contained in the carboxyl group.

[0040] Examples of the aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms include 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter, also referred to as 6FDA), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride (hereinafter, also referred to as PMDA), 1,2,3,4-benzenetetracarboxylic anhydride, 3,3',4,4'-benzophenonetetracarboxylic anhydride, 2,2',3,3'-benzophenonetetracarboxylic anhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride (hereinafter, also referred to as BPDA), 3,3',4,4'-dicarboxylic anhydride, and 1,2,3,4-benzenetetracarboxylic anhydride. Phenylsulfonate tetracarboxylic dianhydride (hereinafter, also referred to as DSDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2-propylene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride (hereinafter, also referred to as ODPA ), terephthalic acid dianhydride (hereinafter, also referred to as TAHQ) thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid dianhydride, 1,3-bis(3,-dicarboxyphenyl)phthalic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic acid dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic acid dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic acid dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic acid dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenyl)-

[0063] Examples of the present invention include 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic dianhydride.

[0041] As the aliphatic tetracarboxylic dianhydride having 6 to 50 carbon atoms, for example, ethyl tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, etc. can be mentioned; Examples of the alicyclic tetracarboxylic dianhydride having 6 to 36 carbon atoms include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclopentanonebisspironorthanetetracarboxylic dianhydride (hereinafter also referred to as CPODA), 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-12-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, Propyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, REL-[1S,5R,6R]-3-oxabicyclo[3,2]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'dione), 4-(2,5-dioxatetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-3,4-dicarboxylic acid anhydride phenyl) ether, etc.

[0042] In a preferred embodiment, X1 is derived from at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4'-biphenyl bis(trimellitic acid monoester anhydride) (TAHQ), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 3,3',4,4'-diphenylsulfonate tetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic anhydride (ODPA), and cyclopentanone bis(spironorthane tetracarboxylic dianhydride) (CPODA).

[0043] From the viewpoint of balance among coefficient of linear expansion (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature region, PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA are preferred, and BPDA, TAHQ, and ODPA are more preferred.

[0044] For example, the polyamide-imide copolymer can be obtained by using a dicarboxylic acid in addition to the above-mentioned tetracarboxylic dianhydride as a polyimide precursor within a range that does not impair its performance. By using such a precursor, various properties such as the increase in mechanical elongation, the increase in glass transition temperature, and the decrease in yellowness can be adjusted in the obtained film. As such a dicarboxylic acid, a dicarboxylic acid having an aromatic ring and an alicyclic dicarboxylic acid can be exemplified. It is particularly preferred to be at least one compound selected from the group consisting of an aromatic dicarboxylic acid having a carbon number of 8 to 36 and an alicyclic dicarboxylic acid having a carbon number of 6 to 34. The carbon number mentioned here also includes the number of carbons contained in the carboxyl group. Among them, a dicarboxylic acid having an aromatic ring is preferred.

[0045] Specific examples of dicarboxylic acids include isophthalic acid, terephthalic acid, 4,4'-biphenyl dicarboxylic acid, 3,4'-biphenyl dicarboxylic acid, 3,3'-biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-sulfonyl dibenzoic acid, 3,4'-sulfonyl dibenzoic acid, 3,3'-sulfonyl dibenzoic acid, 4,4'-oxydibenzoic acid, 3,4'-oxydibenzoic acid, 3,3'-oxydibenzoic acid, 2,2-bis(4-carboxyphenyl)propane, 2,2-bis(4-carboxyphenyl)propane, (3-Carboxyphenyl) propane, 2,2'-dimethyl-4,4'-biphenyl dicarboxylic acid, 3,3'-dimethyl-4,4'-biphenyl dicarboxylic acid, 2,2'-dimethyl-3,3'-biphenyl dicarboxylic acid, 9,9-bis(4-(4-carboxyphenoxy)phenyl)fluorene, 9,9-bis(4-(3-carboxyphenoxy)phenyl)fluorene, 4,4'-bis(4-carboxyphenoxy)biphenyl, 4,4'-bis(3-carboxyphenoxy)biphenyl, 3,4'-bis(4-carboxyphenoxy)biphenyl, 3,4'-bis(3-carboxyphenoxy)biphenyl, 3,3'-bis( 4-carboxyphenoxy)biphenyl, 3,3'-bis(3-carboxyphenoxy)biphenyl, 4,4'-bis(4-carboxyphenoxy)-p-terphenyl, 4,4'-bis(4-carboxyphenoxy)-m-terphenyl, 3,4'-bis(4-carboxyphenoxy)-p-terphenyl, 3,3'-bis(4-carboxyphenoxy)-p-terphenyl, 3,4'-bis(4-carboxyphenoxy)-m-terphenyl, 3,3'-bis(4-carboxyphenoxy)-m-terphenyl, 4,4'-bis(3-carboxyphenoxy)-p-terphenyl, 4,4'-bis(3-carboxyphenoxy)-m-terphenyl Triphenyl, 3,4'-bis(3-carboxyphenoxy)-p-terphenyl, 3,3'-bis(3-carboxyphenoxy)-p-terphenyl, 3,4'-bis(3-carboxyphenoxy)-m-terphenyl, 3,3'-bis(3-carboxyphenoxy)-m-terphenyl, 1,1-cyclobutanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, and the like; and 5-aminoisophthalic acid derivatives described in the handbook of International Publication No. 2005 / 068535, etc. When the dicarboxylic acids are actually copolymerized with the polymer, they can also be used in the form of acyl chlorides derived from thionyl chloride or the like, active esters, and the like.

[0046] In the above general formula (1), X2 is a divalent organic group, preferably a structure represented by the following general formula (A-1), a structure represented by the following general formula (A-4), a structure represented by the following general formula (A-5), a structure represented by the following general formula (A-6), a structure derived from a diamine represented by the following general formula (B-1), or a structure derived from BAFL, BFAF, BAOFL, 44DAS, 33DAS, 44ODA, 34ODA, etc. As X2, from the viewpoint of yellowness (YI value) in a high temperature range, a structure derived from 4-aminophenyl-4-aminobenzoate is preferred, and from the viewpoint of haze (HAZE value), a structure derived from at least one of 4-aminobenzoic acid 4-amino-3-fluorophenyl ester (APAB), p-phenylenediamine (pPD), BAFL, and BFAF is preferred.

[0047] In one embodiment, the structure of X2 in the general formula (1) is represented by the following general formula (A-1): [Chemistry 47] {wherein, R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, a and b each independently represent an integer of 0 to 4, and * represents a bonding portion}.

[0048] Here, R1 and R2 are not limited, and they are independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when a and / or b=0), or a halogen. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy. When a and / or b=0, hydrogen may be used, or fluorine may be used as a halogen. Among them, hydrogen and / or phenyl are preferred from the perspective of yellowness (YI value) in a high temperature region, and at least one selected from the group consisting of hydrogen, methyl, and fluorine is preferred from the perspective of haze (Haze value).

[0049] Here, a and b are not limited and may be integers of 0 to 4. In terms of yellowness (YI value) and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the perspective of yellowness (YI value) in a high temperature region.

[0050] In one embodiment, the structure of X2 in the general formula (1) is represented by the following general formula (A-6): [Chemistry 48] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion}.

[0051] Here, R 14 and R 15 are not limited, and they are independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when n and o=0), or a halogen. Such an organic group may be, for example, an alkyl group such as methyl, ethyl, propyl, a halogen-containing group such as a trifluoromethyl group, an alkoxy group such as a methoxy group, an ethoxy group, etc.; when n and o=0, it may be hydrogen, or as a halogen, fluorine may be cited as an example. Among them, from the perspective of yellowness (YI value) in a high temperature region, hydrogen and / or phenyl are preferred, and from the perspective of haze (Haze value), at least one selected from the group consisting of hydrogen, methyl, and fluorine is preferred.

[0052] Here, n and o are not limited and may be integers of 0 to 4. In terms of yellowness (YI value) and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the perspective of yellowness (YI value) in a high temperature range.

[0053] In one embodiment, the structure of X2 in the general formula (1) is represented by the following general formula (A-2): [Chemistry 49] {wherein, R 3 represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, c is an integer of 0 to 4, and * represents a bonding portion}.

[0054] Here, R 3 is not limited, and each independently represents a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when c=0), or halogen. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy. When c=0, it may be hydrogen, or halogen may include fluorine. Among them, hydrogen is preferred from the perspective of yellowness (YI value) in the high temperature region, and methyl and / or fluorine are preferred from the perspective of haze (Haze value).

[0055] Here, c is not limited and may be an integer of 0 to 4. In terms of yellowness (YI value) and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the perspective of yellowness (YI value) in a high temperature region.

[0056] In one embodiment, the structural unit represented by the general formula (A-1) is derived from a diamine represented by the following general formula (B-1): [Chemistry 50] {wherein, R1, R2, a and b are defined in the same manner as in the general formula (A-1)}.

[0057] More specifically, examples of the diamine represented by the general formula (B-1) include 4-aminophenyl-4-aminobenzoate (hereinafter, also referred to as APAB), 2-methyl-4-aminophenyl-4-aminobenzoate (hereinafter, also referred to as 2Me-APAB), 3-methyl-4-aminophenyl-4-aminobenzoate (hereinafter, also referred to as 3Me-APAB), 2-fluoro-4-aminophenyl-4-aminobenzoate (hereinafter, also referred to as 2F-APAB), -APAB), 3-fluoro-4-aminophenyl-4-aminobenzoate (hereinafter, also recorded as 3F-APAB), 3-methyl-4-aminophenyl-3-methyl-4-aminobenzoate (hereinafter, also recorded as 3,3Me-APAB), etc.; from the viewpoint of yellowness (YI value) in the high temperature region, APAB is preferred, and from the viewpoint of reducing haze (Haze value), APAB, 3Me-APAB, and 3F-APAB are preferred.

[0058] In one embodiment, the structural unit represented by the general formula (A-2) is derived from a diamine represented by the following general formula (B-2): [Chemistry 51] {wherein, R 3 and c are defined in the same manner as in the general formula (A-2)}.

[0059] More specifically, examples of the diamine represented by the general formula (B-2) include p-phenylenediamine (pPD), m-phenylenediamine, and 3,5-diaminobenzoic acid. From the viewpoint of heat resistance at high temperatures, pPD is preferred.

[0060] The polyamine, polyimide, polyamine-imide copolymer, and polyimide copolymer may use other diamines in addition to or in place of the diamines represented by the general formula (B-1) and the general formula (B-2) as long as the yellowness, haze, residual stress, etc. are not impaired.

[0061] Examples of other diamines include 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4 -bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, etc.; preferably, one or more selected from the group consisting of the above are used. The content of the above other diamines in the total diamines is preferably 20 mol% or less, and more preferably 10 mol% or less. On the other hand, from the viewpoint of heat resistance at high temperatures, it is preferred that the diamine used does not contain polysiloxane diamines. For example, "X-22-9409" and "X-22-1660B-3" manufactured by Shin-Etsu Chemical Co., Ltd., which can be obtained as commercial products of polysiloxane diamines, can be cited.

[0062] The molar ratio (X2 / X1) of X1 to X2 in the polyamide moiety contained in the general formula (1) is preferably 0.84 to 1.00 or 0.85 to 1.2, more preferably 0.90 to 1.1, and further preferably 0.92 to 1.00. If X1 / X2 is 0.84 or more or 0.85 or more, the residual stress is reduced and the YI is reduced. If X1 / X2 is 1.2 or less or 1.00 or less, the mechanical properties such as elongation and breaking strength are excellent.

[0063] The weight average molecular weight (Mw) of the polyamide and the polyamide portion is preferably 1,000 or more, more preferably 1,000 to 300,000 or 2,639 to 300,000, further preferably 10,000 to 200,000 or 10,000 to 250,000, and particularly preferably 30,000 to 200,000. If the weight average molecular weight is 1,000 or more, mechanical properties such as elongation and breaking strength are excellent, residual stress is reduced, and YI is reduced. If the weight average molecular weight is 300,000 or less, it is easy to control the weight average molecular weight during the synthesis of the polyamide, and a resin composition with a moderate viscosity can be obtained, and the coating property of the resin composition becomes better. Furthermore, if the Mw of the polyamide and the polyamide portion is 170,000 or more, the transparency, haze, heat resistance and linear expansion coefficient tend to be excellent, so it is preferred, and the Mw of 220,000 or more is more preferred. This tendency is significant when the structure represented by the above general formula (A-1) is used as X2 in the general formula (1). In the present invention, the weight average molecular weight is a value obtained using gel permeation chromatography (hereinafter, also referred to as GPC) as a standard polystyrene conversion value.

[0064] (b) <Embodiment of Polyimide Section> The polyimide portion constituting the polyamide-imide copolymer of the present invention is represented by the structural unit M in the above general formula (1).

[0065] In the above general formula (1), X3 is a tetravalent organic group, preferably a structure selected from the structure represented by the following general formula (A-3), or a structure selected from at least one of 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and a tetravalent organic group derived from tetracarboxylic anhydride described in the above <Implementation Method of Polyamide Part> can be used. In addition, the plurality of X3 present in the polyamide-imide copolymer that can be used as a polyimide precursor can be the same or different, and can be the same or different from X1.

[0066] As X3, from the viewpoint of yellowness (YI value) in a high temperature region, a structure derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF) is preferred, and from the viewpoint of residual stress, a structure derived from ODPA is preferred.

[0067] As tetracarboxylic dianhydrides that can be used in addition to or in place of the above-mentioned BPAF, ODPA, and 6FDA, there can be exemplified aromatic tetracarboxylic dianhydrides having a carbon number of 8 to 36, aliphatic tetracarboxylic dianhydrides having a carbon number of 6 to 50, and alicyclic tetracarboxylic dianhydrides having a carbon number of 6 to 36. Among them, from the viewpoint of yellowness in a high temperature range, aromatic tetracarboxylic dianhydrides having a carbon number of 8 to 36 are preferred. The carbon number mentioned here also includes the number of carbons contained in the carboxyl group.

[0068] Examples of the aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms include 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter, also referred to as 6FDA), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride (hereinafter, also referred to as PMDA), 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter, also referred to as BPDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 1,2,3,4-benzenetetracarboxylic dianhydride. 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride (hereinafter, also referred to as ODPA), 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2-propylene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride (hereinafter, also referred to as ODPA) ), terephthalic acid dianhydride (hereinafter, also referred to as TAHQ) thio-4,4'-diphthalic acid dianhydride, sulfonyl-4,4'-diphthalic acid dianhydride, 1,3-bis(3,-dicarboxyphenyl)phthalic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic acid dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic acid dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic acid dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic acid dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenyl)-

[0063] Examples of the present invention include 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic dianhydride.

[0069] As the aliphatic tetracarboxylic dianhydride having a carbon number of 6 to 50, for example, ethylene tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, etc. can be mentioned; Examples of the alicyclic tetracarboxylic dianhydride having 6 to 36 carbon atoms include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclopentanonebisspironorthanetetracarboxylic dianhydride (hereinafter also referred to as CPODA), 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-12-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 2,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, Propyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, REL-[1S,5R,6R]-3-oxabicyclo[3,2]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'dione), 4-(2,5-dioxatetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, ethylene glycol-bis-3,4-dicarboxylic acid anhydride phenyl) ether, etc.

[0070] In a preferred embodiment, X1 or X3 is derived from at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4'-biphenyl bis(trimellitic acid monoester anhydride) (TAHQ), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 3,3',4,4'-diphenylsulfonate tetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic anhydride (ODPA), and cyclopentanone bis(spironorthane tetracarboxylic dianhydride) (CPODA).

[0071] From the viewpoint of balance among coefficient of linear expansion (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature region, PMDA, BPDA, DSDA, TAHQ, and CPODA are preferred, and BPDA and TAHQ are more preferred.

[0072] Regarding the polyamide-imide copolymer, for example, it can also be obtained by using a dicarboxylic acid as a polyimide precursor in addition to the above-mentioned tetracarboxylic dianhydride within a range that does not impair its performance. By using such a precursor, various properties such as the improvement of mechanical elongation, the improvement of glass transition temperature, and the reduction of yellowness can be adjusted in the obtained film. As such a dicarboxylic acid, a dicarboxylic acid having an aromatic ring and an alicyclic dicarboxylic acid can be exemplified. It is particularly preferred to be at least one compound selected from the group consisting of an aromatic dicarboxylic acid having a carbon number of 8 to 36 and an alicyclic dicarboxylic acid having a carbon number of 6 to 34. The carbon number here also includes the number of carbons contained in the carboxyl group. Among them, a dicarboxylic acid having an aromatic ring is preferred.

[0073] Specific examples of dicarboxylic acids include isophthalic acid, terephthalic acid, 4,4'-biphenyl dicarboxylic acid, 3,4'-biphenyl dicarboxylic acid, 3,3'-biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-sulfonyl dibenzoic acid, 3,4'-sulfonyl dibenzoic acid, 3,3'-sulfonyl dibenzoic acid, 4,4'-oxydibenzoic acid, 3,4'-oxydibenzoic acid, 3,3'-oxydibenzoic acid, 2,2-bis(4-carboxyphenyl)propane, 2,2-bis(4-carboxyphenyl)propane, (3-Carboxyphenyl) propane, 2,2'-dimethyl-4,4'-biphenyl dicarboxylic acid, 3,3'-dimethyl-4,4'-biphenyl dicarboxylic acid, 2,2'-dimethyl-3,3'-biphenyl dicarboxylic acid, 9,9-bis(4-(4-carboxyphenoxy)phenyl)fluorene, 9,9-bis(4-(3-carboxyphenoxy)phenyl)fluorene, 4,4'-bis(4-carboxyphenoxy)biphenyl, 4,4'-bis(3-carboxyphenoxy)biphenyl, 3,4'-bis(4-carboxyphenoxy)biphenyl, 3,4'-bis(3-carboxyphenoxy)biphenyl, 3,3'-bis( 4-carboxyphenoxy)biphenyl, 3,3'-bis(3-carboxyphenoxy)biphenyl, 4,4'-bis(4-carboxyphenoxy)-p-terphenyl, 4,4'-bis(4-carboxyphenoxy)-m-terphenyl, 3,4'-bis(4-carboxyphenoxy)-p-terphenyl, 3,3'-bis(4-carboxyphenoxy)-p-terphenyl, 3,4'-bis(4-carboxyphenoxy)-m-terphenyl, 3,3'-bis(4-carboxyphenoxy)-m-terphenyl, 4,4'-bis(3-carboxyphenoxy)-p-terphenyl, 4,4'-bis(3-carboxyphenoxy)-m-terphenyl Triphenyl, 3,4'-bis(3-carboxyphenoxy)-p-terphenyl, 3,3'-bis(3-carboxyphenoxy)-p-terphenyl, 3,4'-bis(3-carboxyphenoxy)-m-terphenyl, 3,3'-bis(3-carboxyphenoxy)-m-terphenyl, 1,1-cyclobutanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, and the like; and 5-aminoisophthalic acid derivatives described in the handbook of International Publication No. 2005 / 068535, etc. When the dicarboxylic acids are actually copolymerized with the polymer, they can also be used in the form of acyl chlorides derived from thionyl chloride or the like, active esters, and the like.

[0074] In one embodiment, the structure of X 3 in the general formula (1) or the following general formula (2) is represented by the following general formula (A-3): [Chemistry 52] {wherein, R4 to R7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or a halogen, d to g each independently represent an integer of 0 to 4, Z1 represents a bonding group, and * represents a bonding portion} The represented or derived from 4,4'-oxydiphthalic dianhydride (ODPA) and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA).

[0075] Here, R6~R9 are not limited, and they are independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when d~g=0), or a halogen. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy; when d~g=0, it may be hydrogen, or as a halogen, fluorine may be mentioned. Among them, hydrogen is preferred from the perspective of yellowness (YI value) in the high temperature region, and fluorine is preferred from the perspective of haze (Haze value).

[0076] Here, Z1 may be exemplified by a single bond, a methylene group, an ethylidene group, an ether, a ketone, etc. Among them, a single bond is more preferred from the viewpoint of YI in a high temperature region, and a single bond and an ether are more preferred from the viewpoint of residual stress.

[0077] Here, d to g are not limited, and each may be an integer of 0 to 4. In terms of yellowness (YI value) and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the perspective of yellowness (YI value) in a high temperature region.

[0078] In one embodiment, the structural unit represented by the general formula (A-3) is derived from an acid dianhydride represented by the following general formula (B-3): [Chemistry 53] {wherein, R 4 to R 7, d to g, and Z 1 are defined similarly to the general formula (A-3), d and e are preferably each independently an integer of 0 to 3, and f and g are preferably each independently an integer of 0 to 4}.

[0079] As the acid dianhydride represented by the general formula (B-3), more specifically, 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluoranhydride (BPF-PA), etc. can be exemplified. From the viewpoint of reducing the haze (Haze value) and the high temperature range, BPAF is preferred, and from the viewpoint of residual stress, BPAF and BPF-PA are preferred.

[0080] In the general formula (1) or the following general formula (2), X4 is a divalent organic group, preferably a structure represented by at least one of the following general formulas (A-4) to (A-6), and a divalent organic group derived from a diamine described in the above <Embodiment of the polyamide part> can be used. In addition, a plurality of X4 present in the polyimide or the polyimide part may be the same or different from each other, and from the viewpoint of achieving opposite properties at the same time when the polyimide is prepared, it is preferably different from X2, and more preferably, the diamine component constituting X2 is different from the diamine component constituting X4 in either the diamine composition or the diamine type.

[0081] In one embodiment, the structure of X4 in the general formula (1) or the following general formula (2) is represented by the following general formula (A-4): [Chemistry 54] {wherein, R 8 to R 11 each independently represents a monovalent organic group having 1 to 20 carbon atoms, or a halogen, h to k each independently represent an integer of 0 to 4, Z 2 represents a bonding group, and * represents a bonding portion}.

[0082] Here, R 8 to R 11 are not limited, and they are independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when h~k=0), or a halogen. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy; when h~k=0, it may be hydrogen, or as a halogen, fluorine may be mentioned. Among them, hydrogen is preferred from the perspective of yellowness (YI value) in the high temperature region, and fluorine is preferred from the perspective of haze (Haze value).

[0083] Here, h~k are not limited, and may be integers of 0~4. In terms of yellowness (YI value) and residual stress, an integer of 0~2 is preferred, and 0 is particularly preferred from the perspective of yellowness (YI value) in a high temperature range.

[0084] As Z2, there can be exemplified a single bond, methylene, vinyl, ether, ketone, etc. Among them, from the viewpoint of YI in a high temperature region, a single bond is preferred.

[0085] In one embodiment, the structure of X4 in the general formula (1) or the following general formula (2) is represented by the following general formula (A-5): [Chemistry 55] {wherein, R12 and R13 each independently represent a monovalent organic group having 1 to 20 carbon atoms or a halogen, l and m each independently represent an integer of 0 to 4, and * represents a bonding portion, wherein in the above general formula (1), when X2 is a group derived from 4-aminobenzoic acid 4-amino-3-fluorophenyl ester, and X3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), the general formula (A-5) excludes 4,4'-diaminodiphenylsulfone or a group derived therefrom}.

[0086] Here, R12 and R13 are not limited, and they can be independently a monovalent organic group having 1 to 20 carbon atoms or a halogen such as fluorine. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, aryl groups such as phenyl and naphthyl, and alkoxy groups such as methoxy and ethoxy. Among them, methyl is preferred from the viewpoint of YI in the high temperature region.

[0087] Here, l and m are not limited and may be integers of 0 to 4. In terms of YI and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the perspective of YI in a high temperature region.

[0088] In one embodiment, the structure of X4 in the general formula (1) or the following general formula (2) is represented by the following general formula (A-6): [Chemistry 56] {wherein, R 14 and R 15 each independently represent a monovalent organic group having 1 to 20 carbon atoms, or a halogen, n and o each independently represent an integer of 0 to 4, and * represents a bonding portion}. Here, R 14 and R 15 are not limited, and each independently represents a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl groups; halogen-containing groups such as trifluoromethyl groups; aryl groups such as phenyl and naphthyl groups; alkoxy groups such as methoxy and ethoxy groups; and the like. Among them, methyl and phenyl groups are preferred from the viewpoint of YI in the high temperature region. Here, n and o are not limited, and may be integers of 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferred, and 0 is particularly preferred from the viewpoint of YI in the high temperature region.

[0089] In one embodiment, the structural unit represented by the general formula (A-4) is derived from a diamine represented by the following general formula (B-4): [Chemistry 57] {wherein, R 8 to R 11 and h to k are defined in the same manner as in the general formula (A-4)}.

[0090] More specifically, the diamine represented by the general formula (B-4) includes 9,9-bis(4-aminophenyl)fluorene (BAFL), 9,9-bis(3-fluoro-4-aminophenyl)fluorene (BFAF), 9,9-bis(4-(aminophenoxy)phenyl)fluorene (BAOFL), etc. From the viewpoint of yellowness (YI value) at high temperature, BFAF is preferred, and from the viewpoint of reducing haze (Haze value), BAFL is preferred.

[0091] In one embodiment, the structural unit represented by the general formula (A-5) is derived from the following general formula (B-5-1): [Chemistry 58] Or the following general formula (B-5-2): [Chemistry 59] {wherein, R 12 and R 13, l and m are defined in the same manner as in the general formula (A-5)} The diamines represented by

[0092] As the diamine represented by the general formula (B-5-1) and (B-5-2), more specifically, 4,4'-diaminodiphenylsulfone (44DAS) and 3,3'-diaminodiphenylsulfone (33DAS) can be exemplified. As other diamines, more specifically, bis[4-(4-aminophenoxy)phenyl]sulfone and bis[4-(3-aminophenoxy)phenyl]sulfone can be exemplified. From the viewpoint of yellowness (YI value) at high temperature, 44DAS is preferred, and from the viewpoint of reducing residual stress, 33DAS is preferred.

[0093] In one embodiment, the structural unit represented by the general formula (A-6) is derived from a diamine represented by the following general formula (B-6): [Chemistry 60] {wherein, R 14 and R 15, n and o are defined in the same manner as in the general formula (A-6)}.

[0094] More specifically, the diamine represented by the general formula (B-6) includes 4,4'-diaminodiphenyl ether (44ODA), 3,4'-diaminodiphenyl ether (34ODA), 2,3'-diaminodiphenyl ether, etc. From the viewpoint of yellowness (YI value) at high temperature, 44ODA is preferred, and from the viewpoint of reducing residual stress, 34ODA is preferred.

[0095] The weight average molecular weight (Mw) of the polyimide or polyimide portion is preferably 1,000 to 100,000, more preferably 2,000 to 80,000 or 2,639 to 80,000, and particularly preferably 5,000 to 60,000. If the weight average molecular weight is 1,000 or more, mechanical properties such as elongation and breaking strength are excellent, residual stress is reduced, and YI is reduced. If the weight average molecular weight is 100,000 or less, phase separation is suppressed when the polyamide-imide copolymer membrane is prepared, and the haze (HAZE value) is reduced. In the present invention, the weight average molecular weight is a value obtained using gel permeation chromatography (hereinafter, also referred to as GPC) as a standard polystyrene conversion value.

[0096] Regarding polyimide or its structural unit, the molar ratio (X4 / X3) of X3 and X4 contained in the above general formula (1) is preferably 0.85 to 2.0 or 1.01 to 2.00, more preferably 0.95 to 1.5, and further preferably 1.01 to 1.25. If the molar ratio is 0.85 or more or 1.01 or more, the heat resistance in the high temperature range is excellent and the YI value is reduced. If the molar ratio is 2.00 or less, the reactivity with the polyimide part is improved, and the strength when formed into a film is increased, so that the mechanical properties such as elongation and breaking strength are excellent.

[0097] The content of molecules with a molecular weight of less than 1,000 in the polyimide or polyimide portion is preferably less than 5% by mass, more preferably less than 1% by mass, and further preferably less than 0.1% by mass relative to the total amount of the polyimide precursor or the polyamide-imide copolymer. The residual stress of a polyimide film formed from a resin composition obtained by using such a polyimide or polyimide portion is reduced, and the haze value (Haze value) formed on the polyimide film is reduced. The content of molecules with a molecular weight of less than 1,000 relative to the total amount of the polyimide or polyimide portion can be calculated based on the peak area obtained by GPC measurement using a solution in which the polyimide is dissolved.

[0098] In the polyimide precursor in one aspect of the present invention, other diamines may be used in addition to or in place of the diamines represented by the general formulas (B-1) to (B-2) and (B-4) to (B-6) as long as the elongation, strength, stress, and yellowness are not impaired. Examples of other diamines include 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4 -bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, etc.; preferably, one or more selected from the group consisting of the above are used.

[0099] The content of the above other diamines in the total diamines is preferably 20 mol% or less, and more preferably 10 mol% or less. From the viewpoint of heat resistance at high temperatures, it is preferred that X4 and the diamines constituting it do not contain polysiloxane diamines, as in X2, and more preferably are of the type or composition of aromatic diamines.

[0100] (c) <Embodiment of polyamide-imide copolymer> The polyamide-imide copolymer of the present invention comprises a structural unit L represented by the above general formula (1) comprising a structural unit M as a polyamide portion and a structural unit N as a polyimide portion, and a specific embodiment thereof is shown below.

[0101] The diamine (X2) in the polyamide part and the diamine (X4) in the polyimide part may have the same composition or diamine type, or may have different compositions or diamine types. The "same composition" mentioned here means that when the diamine used in the polyamide part includes one or more diamines, the diamine in the polyimide part has exactly the same composition. On the other hand, the "different composition" mentioned here means that when the diamine used in the polyamide part includes one or more diamines, the diamine in the polyimide part does not have exactly the same composition, but includes different diamines, or even if the same diamine is used, the ratio is different.

[0102] The function of the polyamide portion in one aspect of the present invention is to have higher thermal stability in high temperature regions, excellent dimensional stability, preferably a skeleton with higher molecular planarity and higher heat resistance at high temperatures when made into polyimide.

[0103] The acid dianhydride (X1) of the polyamide portion is, as shown in (a) <embodiment of the polyamide portion>, derived from at least one selected from the group consisting of pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4'-biphenylbis(trimellitic acid monoester anhydride) (TAHQ), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 3,3',4,4'-diphenylsulfonate tetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic anhydride (ODPA), and cyclopentanone bis(spironorthane tetracarboxylic dianhydride) (CPODA).

[0104] From the viewpoint of the balance of the coefficient of linear expansion (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in the high temperature region, PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA are preferred, and BPDA, TAHQ, and ODPA are more preferred. As X1, in addition to the acid dianhydride represented above, it can also be obtained by using dicarboxylic acid in addition to the above-mentioned tetracarboxylic dianhydride within the range that does not impair its performance. In addition, other tetracarboxylic dianhydrides can also be added, but it is preferably a skeleton derived from aromatic tetracarboxylic dianhydride or aromatic dicarboxylic acid. In addition, the ratio of other acid dianhydrides and dicarboxylic acids in X1 is preferably 20 mol% or less, and more preferably 10 mol% or less.

[0105] As the diamine (X 2), preferably at least one selected from the group consisting of (4-aminophenyl-4-aminobenzoate (APAB), 2-methyl-4-aminophenyl-4-aminobenzoate, 3-methyl-4-aminophenyl-4-aminobenzoate, 2-fluoro-4-aminophenyl-4-aminobenzoate (2F-APAB), 3-fluoro-4-aminophenyl-4-aminobenzoate (3F-APAB), 3-methyl-4-aminophenyl-3-methyl-4-aminobenzoate, and (2-phenyl-4-aminophenyl)-4-aminobenzoate (ph-APAB). From the viewpoint of the balance among the coefficient of linear expansion (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature region, APAB, 2F-APAB, 3F-APAB, and Ph-APAB are preferred, and APAB is more preferred. As X 2. In addition to the acid dianhydride shown above, other diamines may be added within the range that does not impair its performance, but do not contain a cyclohexane ring or a cyclopentane ring, and are preferably aromatic diamines. The ratio of other diamines in X2 is preferably 20 mol% or less, and more preferably 10 mol% or less. That is, the diamine (X4) as the above-mentioned imide part preferably does not contain the structure shown above, but it is not necessarily limited to this, as long as the composition is not completely the same.

[0106] The function of the imide part in one aspect of the present invention is to have higher thermal stability in the high temperature region, excellent optical properties, and higher solubility in solvents. Preferably, it is a skeleton having excellent optical properties and higher solubility in solvents or a skeleton that can impart bending resistance when made into a film.

[0107] As the acid dianhydride (X3) of the above-mentioned polyimide part, as shown in (b) <Implementation Method of the Polyimide Part>, a tetravalent organic group derived from tetracarboxylic dianhydride can be used. In addition, the multiple X3 present in the polyimide precursor or the polyamide-imide copolymer may be the same as or different from each other, and may be the same as or different from X1. As X3, from the perspective of excellent yellowness (YI value) and haze (Haze value) in the high temperature region, it is preferred to include a structure derived from BPAF, and from the perspective of residual stress, it is preferred to include a structure derived from ODPA. In the case of using a skeleton derived from BPAF, in order to improve the thermal stability in the high temperature region, a skeleton selected from PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA can also be used simultaneously. Among them, it is more preferred to include a skeleton selected from BPDA, TAHQ, and ODPA. The ratio of BPAF in X3 is preferably 40 mol% or more, more preferably 50 mol% or more, further preferably 70 mol% or more, and may be 100 mol%. From the viewpoint of excellent bending resistance when the polyimide film is prepared, the higher the ratio of BPAF, the better.

[0108] As the diamine of the above-mentioned imide part, as shown in (b) <Implementation Method of the Polyimide Part>, a divalent organic group derived from a diamine can be used. In addition, the plurality of X4 present in the polyimide precursor or the polyamide-imide copolymer may be the same as or different from each other, and may be the same as or different from X2, but not completely the same. As X4, at least one selected from the group consisting of 44BAFL, 33BAFL, BFAF, BAOFL, BAHF, 33DAS, and 44DAS is preferred. From the viewpoint of the balance of linear expansion coefficient (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in the high temperature region, 44BAFL, 33BAFL, BFAF, BAOFL, 33DAS, 44DAS, 44ODA, and 34ODA are more preferred.

[0109] The polyamide-imide copolymer comprises a polyamide portion including X1 and X2 and a polyimide portion including X3 and X4. The upper limit of the molar ratio of the structural units of the polyamide to the structural units of the polyimide (the molar number of the structural unit N: the molar number of the structural unit M) can be 95:5, 90:10, 85:15, or 80:20. From the viewpoint of residual stress and haze (Haze value), it is preferably 95:5, and from the viewpoint of yellowness (YI value), it is more preferably 80:20. The lower limit of the molar ratio of the structural units of the above-mentioned polyamide and the structural units of the above-mentioned polyimide (the molar number of structural unit N: the molar number of structural unit M) can be 30:70, 40:60, 50:50, or 60:40. From the perspective of making both residual stress and yellowness (YI value) exist at the same time, it is preferably 40:60 or 60:40.

[0110] The weight average molecular weight (Mw) of the polyamide-imide copolymer (structural unit L) is preferably 2,639 or more, more preferably 2,639 to 300,000 or 10,000 to 300,000, further preferably 20,000 to 250,000, and particularly preferably 40,000 to 200,000. If the weight average molecular weight is 2,639 or more, mechanical properties such as elongation and breaking strength are excellent, residual stress is reduced, and YI is reduced. If the weight average molecular weight is 300,000 or less, the balance between viscosity and concentration of the polyamide-imide copolymer varnish is improved, the processability is improved, and the film unevenness during coating is reduced. In addition, if the Mw of the polyamide-imide copolymer is 170,000 or more, it tends to be excellent in transparency, haze, heat resistance and linear expansion coefficient, so it is preferred, and more preferably 220,000 or more. This tendency is significant when the structure represented by the above general formula (A-1) is used as X2 in the general formula (1). In addition, from the viewpoint of IR (infrared) curing defect evaluation and degassing evaluation, the weight average molecular weight (Mw) of the polyamide-imide copolymer is preferably 170,000 or more, and more preferably 220,000 or more. In the present invention, the weight average molecular weight is a value determined using gel permeation chromatography (hereinafter, also referred to as GPC) as a standard polystyrene conversion value.

[0111] <(B) Embodiment of polyamine> Regarding the polyamide of the fourth embodiment comprising a structural unit represented by the general formula (3) and having a structure represented by the general formula (A-1) as X2, in the general formula (3), X1 is a tetravalent organic group, and the plurality of X1 present in the polyimide precursor may be the same as or different from each other. As X1, a tetravalent organic group derived from tetracarboxylic dianhydride may be exemplified, and the tetracarboxylic dianhydride is the same as the tetracarboxylic dianhydride exemplified for the polyamide-imide copolymer (A) above.

[0112] In one embodiment of the polyamide, in the general formula (3), X2 is a divalent organic group, and the plurality of X2 present in the polyimide precursor may be the same as or different from each other. As X2, a divalent organic group derived from a diamine may be exemplified, and the diamine is the same as the diamine exemplified for the polyamide-imide copolymer (A) above.

[0113] Regarding the polyamide, the structural unit represented by the general formula (A-1) is the same as the general formula (A-1) exemplified in relation to the above-mentioned (A) polyamide-imide copolymer.

[0114] The weight average molecular weight (Mw) of the polyamide of the fourth embodiment is preferably 3,000 or more, more preferably 10,000 to 300,000, further preferably 20,000 to 250,000, and particularly preferably 40,000 to 200,000. If the weight average molecular weight is 3,000 or more, mechanical properties such as elongation and breaking strength are excellent, residual stress is reduced, and YI is reduced. If the weight average molecular weight is 300,000 or less, the balance between viscosity and concentration of the polyamide-imide copolymer varnish is improved, the processability is improved, and the film unevenness during coating is reduced.

[0115] In addition, from the viewpoint of IR (infrared) curing defect evaluation and degassing evaluation, the weight average molecular weight (Mw) of the polyamide in the fourth embodiment is preferably 170,000 or more, and more preferably 240,000 or more. In the present invention, the weight average molecular weight is a value obtained using gel permeation chromatography (hereinafter, also referred to as GPC) as a standard polystyrene conversion value.

[0116] (Diamine) Examples of the diamine containing a P1 group in the general formula (I) and (II) include: 4,4'-diaminodiphenyl sulfone (4,4'-DAS), 3,4'-diaminodiphenyl sulfone (3,4'-DAS), 3,3'-diaminodiphenyl sulfone (3,3'-DAS), p-phenylenediamine (PDA), m-phenylenediamine, 3,5-diaminobenzoic acid (DABA), 2,2'-dimethylbenzidine (mTB), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminobenzanilide (DABAN). , 9,9-bis(4-aminophenylfluorene) (BAFL), 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 4-aminobenzoic acid-4-aminophenyl ester (APAB), 2-(4-aminophenyl)-5-aminobenzoxazole, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene 、1,3-bis(4-aminophenoxy)benzene、1,3-bis(3-aminophenoxy)benzene、bis[4-(4-aminophenoxy)phenyl]sulfone、4,4-bis(4-aminophenoxy)biphenyl(BAPB)、4,4-bis(3-aminophenoxy)biphenyl、bis[4-(4-aminophenoxy)phenyl]ether、bis[4-(3-aminophenoxy)phenyl]ether、1,4-bis(4-aminophenyl)benzene、1,3-bis(4-aminophenyl)benzene、9,10-bis(4-aminophenyl)anthracene、2,2-bis(4-aminophenyl)propane、2,2-bis(4-aminophenyl)hexafluoropropane、2,2- Bis[4-(4-aminophenoxy)phenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene] (BiSAM), 1,4-cyclohexanediamine (CHDA), 2,2'-bis(trifluoromethyl)benzidine (TFMB), 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (TFOMB), 2,2''-bis(trifluoromethyl)[1,1':4',1''-terphenyl]-4,4''-diamine, etc. These diamines may be used alone or in combination of two or more.

[0117] In the above general formulae (I) and (II), P1 preferably comprises a structural unit derived from at least one diamine represented by the following general formulae (3) to (12). [Chemistry 61] Diaminodiphenylsulfone (DAS) [Chemistry 62] 4-Aminophenyl 4-aminobenzoate (APAB) [Chemistry 63] 2,2'-Bis(trifluoromethyl)benzidine(TFMB) [Chemistry 64] 9,9-Bis(4-aminophenylfluorene)(BAFL) [Chemistry 65] 4,4'-Diaminobenzanilide (DABAN) [Chemistry 66] 1,4-Cyclohexanediamine (CHDA) [Chemistry 67] Paraphenylenediamine (PDA) [Chemistry 68] 3,5-Diaminobenzoic acid (DABA) [Chemistry 69] 4,4-Bis(4-aminophenoxy)biphenyl(BAPB) [Chemistry 70] 2,2'-Bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (TFOMB)

[0118] The content of the structure derived from the above diamine compound in the total diamine (excluding the compound in which L1 and L2 are amino groups in the following general formula (13)) may be 20 mol% or more, 40 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, or 95 mol% or more.

[0119] (Acid dianhydride) Examples of the acid dianhydride containing a P2 group in the general formula (I) and (II) include pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonatetetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 1-Ethylene-4,4'-diphthalic anhydride, 2,2-propylene-4,4'-diphthalic anhydride, 1,2-ethylene-4,4'-diphthalic anhydride, 1,3-trimethylene-4,4'-diphthalic anhydride, 1,4-tetramethylene-4,4'-diphthalic anhydride, 1,5-pentamethylene-4,4'-diphthalic anhydride, 4,4'-oxydiphthalic anhydride (ODPA), terephthalic acid (trimellitic anhydride), thio-4,4'-diphthalic anhydride, sulfonyl-4,4'-diphthalic anhydride, 1,3-bis(3,4-dicarboxyphenyl)phthalic anhydride, 1,3-bis(3,4-dicarboxyphenyl)phthalic anhydride (3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic anhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic anhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis (3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride (CpODA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA). These acid dianhydrides may be used alone or in combination of two or more.

[0120] <Silicon-containing compounds> The polyamide, polyamide-imide copolymer, polyimide copolymer, polyimide precursor or polyimide resin described above may include a structure represented by the following general formula (14): [Chemistry 71] {wherein, when R1 and R2 are present in plural numbers, they each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and m represents an integer of 1 to 200}.

[0121] If the structure of general formula (14) is included, the Rth and residual stress of the obtained polyimide film become good, which is preferred.

[0122] In order to make the resin have the structure of the general formula (14), X1 to X4 in the general formulas (1) and (2), or P1 or P2 in the general formulas (I) and (II) may include a structural unit derived from a silicon-containing compound represented by the following general formula (13): [Chemistry 72] {wherein, R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms, R2 and R3 are independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, R4 and R5 are independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms, R6 and R7 are independently a monovalent organic group having 1 to 10 carbon atoms, L1 and L2 are independently an amine group, anhydride group, isocyanate group, carboxyl group, ester group, acyl halide group, hydroxyl group, epoxy group or mercapto group, i is an integer of 1 to 200, j and k are independently an integer of 0 to 200, 0≦j / (i+j+k)≦0.50, and the functional group equivalent is 800 or more}.

[0123] In the resin composition, the silicon-containing compound represented by the general formula (13): 20 mol% or less when the diamine is 100 mol%; or When the acid dianhydride is 100 mol %, it is 20 mol % or less. If the silicon-containing compound is within the above range, it is better from the perspective of the filterability of the obtained polyimide precursor or polyimide resin composition. From the perspective of further improving the filterability, it is more preferable that the silicon-containing compound is 20.0 mol% or less, 19.0 mol% or less, 18.0 mol% or less, 17.0 mol% or less, 16.0 mol% or less, 15.0 mol% or less, or 14.0 mol% or less when the total diamine or total acid dianhydride of the resin composition is 100 mol%. When the total diamine or total acid dianhydride of the resin composition is 100 mol%, the silicon-containing compound may exceed 0 mol%.

[0124] In formula (13), R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms. The divalent organic group having 1 to 10 carbon atoms may be any of a straight chain, a cyclic chain, and a branched chain, and may be saturated or unsaturated. Examples of the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms include straight chain or branched chain alkylene groups such as methylene, ethylene, n-propylene, isopropylene, n-butylene, tertiary butylene, n-pentylene, neopentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, and n-decylene; and cycloalkylene groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, and cyclooctylene. The divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of ethylene, n-propylene, and isopropylene.

[0125] In formula (13), R 2 and R 3 are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one of them is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms.

[0126] The monovalent organic group having 1 to 10 carbon atoms may be straight-chain, cyclic or branched, and may be saturated or unsaturated. For example, examples of the monovalent organic group having 1 to 10 carbon atoms include straight-chain or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl and β-naphthyl.

[0127] The monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms may be any of straight chain, cyclic, and branched, and may be saturated or unsaturated. For example, as the monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, there may be mentioned: straight chain or branched chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, and neopentyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, and cyclopentyl. As the monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, it is preferably at least one selected from the group consisting of methyl, ethyl, and n-propyl.

[0128] In formula (13), R4 and R5 are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one of them is a monovalent aromatic group having 6 to 10 carbon atoms. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. For example, examples of the monovalent organic group having 1 to 10 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl. Examples of the monovalent aromatic group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl, α-naphthyl, β-naphthyl and the like, and preferably phenyl, tolyl or xylyl.

[0129] It is preferred that R6 and R7 in formula (13) are independently monovalent organic groups having 1 to 10 carbon atoms, and at least one of them is an organic group having an unsaturated aliphatic hydrocarbon group. The monovalent organic group having 1 to 10 carbon atoms may be any of linear, cyclic, and branched. Examples of the monovalent organic group having 1 to 10 carbon atoms include: linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl. The monovalent organic group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of methyl, ethyl, and phenyl. The organic group having an unsaturated aliphatic hydrocarbon group may be an unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, and may be any of a linear, cyclic, or branched chain. Examples of unsaturated aliphatic hydrocarbon groups having 3 to 10 carbon atoms include vinyl, allyl, 1-propenyl, 3-butenyl, 2-butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, octenyl, nonenyl, decenyl, ethynyl, propynyl, butynyl, pentynyl, and hexynyl. Unsaturated aliphatic hydrocarbon groups having 3 to 10 carbon atoms are preferably at least one selected from the group consisting of vinyl, allyl, and 3-butenyl.

[0130] In formula (13), some or all of the hydrogen atoms of R1 to R7 may be substituted with halogen atoms such as F, Cl, Br, etc., or may be unsubstituted.

[0131] In formula (13), L1 and L2 are independently a monovalent organic group containing an acid anhydride structure (also referred to as an acid anhydride group), an amine group, an isocyanate group, a carboxyl group, an alkoxycarbonyl group, a halogenated carbonyl group, a hydroxyl group, an epoxy group or a mercapto group. As a monovalent organic group containing an acid anhydride structure, for example, the following formula can be cited: [Chemistry 73] 2,5-dioxatetrahydrofuran-3-yl represented by {in the above formula, "*" represents a bonding bond}.

[0132] Among them, an amine group and an acid anhydride group are preferred, and an amine group is more preferred from the viewpoint of viscosity stability of the resin composition.

[0133] The alkoxy group in the alkoxycarbonyl group may be an alkoxy group having 1 to 6 carbon atoms, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, t-butoxy, etc.

[0134] The halogen atom in the halogenated carbonyl group is preferably a halogen atom other than a fluorine atom, more preferably a chlorine atom or an iodine atom.

[0135] From the viewpoint of the filterability of the resin composition, the functional group equivalent of the silicon-containing compound represented by formula (13) is preferably 800 or more, more preferably 1000 or more, and further preferably 1500 or more. On the other hand, when the functional group equivalent is 500 or less, the filterability sometimes deteriorates. The functional group equivalent here refers to the molecular weight of the silicon-containing compound per 1 mol of functional group (unit: g / mol). The functional group equivalent can be measured according to existing standards and by known methods. In addition, when the functional group equivalent of the silicon-containing compound is 800 or more, the residual stress of the polyimide film under a nitrogen atmosphere is smaller, so it is better. It is believed that the reason is that when the functional group equivalent is above a specific value, the polysiloxane region increases and the stress is relaxed.

[0136] In formula (13), i is an integer of 1 to 200, preferably an integer of 2 to 100, more preferably an integer of 4 to 80, and further preferably an integer of 8 to 40. j and k are each independently an integer of 0 to 200, j may also be an integer of 1 to 200, j and k are preferably integers of 0 to 50, more preferably integers of 0 to 20, and further preferably integers of 0 to 50.

[0137] If the resin in the resin composition has a structure derived from formula (13), the residual stress of the polyimide film measured under a nitrogen atmosphere is good (smaller), which is preferred. The reason for measuring under a nitrogen atmosphere is that in the process of manufacturing a display, when an inorganic film such as SiO or SiN is formed on the polyimide film, it is sometimes exposed to a nitrogen atmosphere, and the residual stress under a nitrogen atmosphere is smaller.

[0138] From the viewpoint of the type of monomer, cost, and molecular weight of the obtained polyimide precursor, L1 and L2 in the general formula (13) are preferably independently amine groups. That is, the silicon-containing compound of the general formula (13) is preferably a silicon-containing diamine. As the silicon-containing diamine, for example, the following general formula (15) is preferred: [Chemistry 74] {wherein, P5 each independently represents a divalent hydrocarbon group, which may be the same or different, P3 and P4 are the same as R2 and R3 defined in the general formula (13), and l represents an integer of 1 to 200} The diamino (poly)siloxane represented.

[0139] Preferred structures of P3 and P4 in the general formula (15) include methyl, ethyl, propyl, butyl, and phenyl. Among them, methyl is preferred.

[0140] In the above general formula (15), l is an integer of 1 to 200, and is preferably an integer of 3 to 200 from the viewpoint of heat resistance of the polyimide obtained by using the silicon-containing diamine represented by formula (15).

[0141] The preferred range of the functional group equivalent of the compound represented by the general formula (15) is the same as that of the silicon-containing compound represented by the general formula (13).

[0142] When the total monomer mass (total mass of polyimide precursor / polyimide) is set to 100 mass %, the content (copolymerization ratio) of the silicon-containing compound represented by the general formula (13) is preferably not less than 0.5 mass % and not more than 20 mass %. When the silicon-containing compound is 0.5% by mass or more, the residual stress generated between the supports can be effectively reduced. When the silicon-containing compound is 20% by mass or less, the obtained polyimide film has good transparency (especially low haze value), which is better from the perspective of achieving higher total light transmittance and higher glass transition temperature.

[0143] As described above, the silicon-containing compound used as the monomer of the polyimide precursor / polyimide can be synthesized using the technical knowledge at the time of application, or commercial products can be used. Examples of commercial products include: two-terminal amine-modified methylphenyl polysilicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-1660B-3 (functional group equivalent 2200), X22-9409 (functional group equivalent 670)), two-terminal anhydride-modified methylphenyl polysilicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-168-P5-B (functional group equivalent 2100)), two-terminal epoxy-modified methylphenyl polysilicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.: X22- 2000 (functional group equivalent 620)), two-terminal amino-modified dimethyl polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.: PAM-E (functional group equivalent 130), X22-161A (functional group equivalent 800), X22-161B (functional group equivalent 1500), KF8012 (functional group equivalent 2200), manufactured by Toray Dow Corning: BY16-853U (functional group equivalent 450), manufactured by JNC: Silaplane FM3311 (number average molecular weight 1000)), two-terminal epoxy-modified dimethyl polysilicone (manufactured by Shin-Etsu Chemical Co., Ltd.: X-22-163A (functional group equivalent 1750), two-terminal alicyclic epoxy-modified dimethyl polysilicone (manufactured by Shin-Etsu Chemical Co., Ltd.: X-22-169B (functional group equivalent 1700)), two-terminal hydroxyl-modified dimethyl polysilicone (manufactured by Shin-Etsu Chemical Co., Ltd.: KF-6 000), two-terminal mercapto-modified dimethyl polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.: X-22-167B (functional group equivalent 1700)), two-terminal acid anhydride-modified dimethyl polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.: X-22-168A (functional group equivalent 1000)), etc. Among them, two-terminal amine-modified dimethyl polysiloxane oil is preferred from the viewpoints of price, improved chemical resistance, and improved Tg.

[0144] (d) Organic solvents The (d) organic solvent is not particularly limited, as long as it can dissolve the above-mentioned (a) polyamine, (b) polyimide, (c) polyamine-imide copolymer and other components used arbitrarily. Specific examples of such (d) organic solvents include aprotic solvents, phenolic solvents, ethers and glycol solvents.

[0145] From the perspective of improving the in-plane uniformity of film thickness and reducing the YI value, the aprotic solvent is preferably polar and / or preferably has a boiling point of 250°C to 350°C, for example, it can be the following aprotic polar substance with a boiling point of 250°C to 350°C.

[0146] Examples of aprotic solvents include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, and amide solvents of the following general formula: [Chemistry 75] {wherein, R12=3-methoxy-N,N-dimethylpropionamide represented by methyl group (manufactured by KJ Chemicals, trade name: Equamide M100), and R12=3-butoxy-N,N-dimethylpropionamide represented by n-butyl group (manufactured by KJ Chemicals, trade name: Equamide B100)}; lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphatiamide and hexamethylphosphotriamide; sulfur-containing solvents such as dimethyl sulfone, dimethylsulfoxide, cyclobutanesulfone, or compounds containing sulfone structure; ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; ester solvents such as (2-methoxy-1-methylethyl) acetate, etc.

[0147] Among them, the aprotic polar solvent preferably includes any one or more of N-methylpyrrolidone, N-ethylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 3-methoxy-N,N-dimethylpropionamide, γ-butyrolactone, γ-valerolactone, and cyclobutanesulfonate, and cyclobutanesulfonate is more preferred.

[0148] Examples of the phenolic solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, and the like; examples of the ether and glycol solvent include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, and 1,4-dioxane.

[0149] From the viewpoint of solubility of polyamine, polyimide, and polyamine-imide copolymer, (d) the organic solvent preferably comprises at least one selected from the group consisting of NMP, GBL, DMF, and DMAc.

[0150] [Other ingredients] The resin composition may further contain (e) an imidization catalyst, an aprotic polar substance, a surfactant, and an alkoxysilane compound in addition to the above-mentioned components (a), (b), (c), and (d).

[0151] ((e) Imidization catalyst) In the step of obtaining a polyimide resin film from a resin composition by imidization, an imidization catalyst may be added to the resin composition.

[0152] The resin composition may contain 0.01 to 0.5 mol% of an imidization catalyst relative to 1 mol of the repeating unit of the (c) polyamine-imide copolymer. By making the content of the imidization catalyst 0.01 mol% or more relative to 1 mol of the repeating unit of the polyamine-imide copolymer, the yellowness (YI value) of the film can be suppressed. In addition, from the perspective of the storage stability of the resin composition, it is preferred that the content of the imidization catalyst is 0.5 mol% or less. The content of the imidization catalyst is more preferably 0.015 to 0.5 mol%, further preferably 0.02 to 0.5 mol%, and particularly preferably 0.02 to 0.15 mol% relative to 1 mol of the repeating unit of the polyamine-imide copolymer.

[0153] (e) The content of the imidization catalyst is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the polyamide-imide copolymer or polyamide described above, from the viewpoint of the effect of the present invention.

[0154] The imidization catalyst is not particularly limited, and examples thereof include pyridine, triethylamine, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), and the like. In addition, as the imidization catalyst, from the viewpoint of the effect of the present invention, preferably used are imidazole compounds such as 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, or N-tert-butoxycarbonylimidazole (N-Boc-imidazole), more preferably 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, imidazole, etc., further preferably 1,2-dimethylimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), 1-methylimidazole, etc., further preferably an imidazole compound containing N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and / or 1-methylimidazole, from the viewpoint of storage stability, particularly preferably N-Boc-imidazole, and from the viewpoint of yellowness (YI value) at high temperature, particularly preferably 1-methylimidazole.

[0155] The imidization catalyst is not particularly limited, and may be a nitrogen-containing compound, specifically, an imidazole compound, a pyridine compound, a tertiary amine compound, or the like.

[0156] Examples of the imidazole compound include 1-methylimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), 2-methylimidazole, 2-phenylimidazole, benzimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 4-methyl-2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1H-imidazole, and 1,2-dimethylimidazole.

[0157] Examples of the pyridine compound include 4-dimethylaminopyridine, 2,2'-bipyridine, nicotinic acid, isoquinoline, pyridine, and 2-methylpyridine.

[0158] Examples of the tertiary amine compound include 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and triethylamine.

[0159] These compounds may be used in combination of two or more.

[0160] Among them, from the viewpoint of the following IR (infrared) curing defect evaluation and degassing evaluation, 1-methylimidazole, N-tert-butoxycarbonylimidazole (N-Boc-imidazole), 2-methylimidazole, 2-phenylimidazole, benzimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 4-methyl-2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole are preferred. As the pyridine compound, 4-dimethylaminopyridine, 2,2'-bipyridine, nicotinic acid, isoquinoline, 2-methylpyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, and N-methylmorpholine are preferred. 1-methylimidazole and N-tert-butoxycarbonylimidazole (N-Boc-imidazole) are more preferred.

[0161] From the viewpoint of IR (infrared) curing defect evaluation and degassing evaluation, the content of the imidization catalyst is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, based on 100 parts by mass of the polyamide-imide copolymer or polyamide.

[0162] The following IR (infrared) curing defect evaluation can be improved by adopting any one of the following a.~c.; a. Using imidization catalyst as additive b. Use a non-protonic polar substance with a boiling point of 250-350 as an additive c. To increase the molecular weight of the polyamide-imide copolymer / polyamide.

[0163] Although the mechanism of the good evaluation of IR (infrared) curing defects is uncertain, it is believed to be related to the promotion of imidization. In other words, it is believed that the cause of IR curing defects is related to the generation of oligomers and the decomposition of these oligomers by infrared rays. It is believed that the reason for the good evaluation of IR (infrared) curing defects is that the use of ab promotes imidization, thereby suppressing the generation of oligomers. In addition, regarding c., it is believed that as long as the molecular weight is increased, the generation of oligomers can be suppressed as a result.

[0164] Furthermore, the following degassing evaluation can be improved by adopting any one or more of the following a.~c.; a. Using imidization catalyst as additive b. Use a non-protonic polar substance with a boiling point of 250-350 as an additive c. To increase the molecular weight of the polyamide-imide copolymer / polyamide.

[0165] Although the mechanism of the good degassing evaluation is uncertain, it is believed to be related to the promotion of imidization. In other words, it is believed that the cause of degassing is related to the low molecular weight components and oligomers remaining in the polyimide film after curing, and the reason for the good degassing evaluation is that the imidization is promoted by using ab, thereby suppressing the generation of low molecular weight components and oligomers. In addition, regarding c., it is believed that as long as the molecular weight is increased, the remaining low molecular weight components and oligomers can be suppressed.

[0166] (f) Aprotic polar substances with a boiling point of 250-350°C The resin composition of one aspect of the present invention comprises a non-protonic polar substance with a boiling point of 250°C to 350°C. The non-protonic polar substance with a boiling point of 250°C to 350°C that can be preferably used is a compound that does not contain an OH group, an NH2 group, an NH group, or an SH group at a boiling point of 250°C to 350°C, and has a chemical structure (functional group) of at least one selected from ketones, esters, carbonates, amides, nitriles, sulfides, and sulfides.

[0167] If the preferred compounds are specifically listed, for example, compounds having a ketone structure with a boiling point of 250°C to 350°C, for example: benzophenone, methyl benzophenone, dimethyl benzophenone, dodecanedione, etc.; Examples of compounds having an ester structure with a boiling point of 250°C to 350°C include dibutyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, 2-phenoxyethyl acetate, butyl benzoate, isopentyl benzoate, dibutyl maleate, ethyl cinnamate, diethylene glycol diacetate, diethyl adipate, and the like; Examples of compounds having a carbonate structure with a boiling point of 250°C to 350°C include diphenyl carbonate, etc.; Examples of compounds having an amide structure with a boiling point of 250°C to 350°C include benzamide, N,N-dimethylbenzamide, and hexamethylenediamine; As the compound having a nitrile structure with a boiling point of 250°C to 350°C, there can be cited: adiponitrile, etc.; Examples of the compound having a sulfoxide structure with a boiling point of 250°C to 350°C include dibutylsulfoxide and diphenylsulfoxide; Examples of the compound having a sulfide structure with a boiling point of 250°C to 350°C include cyclobutane sulfide, 3-methylcyclobutane sulfide, dibutyl sulfide, benzenesulfonamide, and the like. Among these compounds, cyclobutanesulfonate and 3-methylcyclobutanesulfonate are more preferably used.

[0168] When a non-protonic polar substance with a boiling point of 250°C to 350°C is added to a polyamide-imide copolymer or a polyamide precursor alone or in combination with a solvent and then coated and cured (heated), the IR curing defect evaluation and degassing evaluation can be improved. The effect is particularly significant when 5 wt% or more is added when (mass of solvent + mass of non-protonic polar substance) is set to 100 wt%. The upper limit of the amount of non-protonic polar substance added is 100 wt% when (mass of solvent + mass of non-protonic polar substance) is set to 100 wt%, and the more preferred amount is 30 wt% or less.

[0169] (Aprotic polar substances with boiling point of 250℃~350℃) The resin composition preferably contains an aprotic polar substance having a boiling point of 250° C. to 350° C. The aprotic polar substance with a boiling point of 250°C to 350°C that can be preferably used is a compound that does not contain OH groups, NH2 groups, NH groups, and SH groups at a boiling point of 250°C to 350°C and has at least one chemical structure (functional group) selected from ketones, esters, carbonates, amides, nitriles, sulfides, and sulfones. The aprotic polar substance can be repeated with the aprotic solvent described above as long as its boiling point is 250°C to 350°C.

[0170] If the preferred compounds are specifically listed, for example, compounds having a ketone structure with a boiling point of 250°C to 350°C, for example: benzophenone, methyl benzophenone, dimethyl benzophenone, dodecanedione, etc.; Examples of compounds having an ester structure with a boiling point of 250°C to 350°C include dibutyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, 2-phenoxyethyl acetate, butyl benzoate, isopentyl benzoate, dibutyl maleate, ethyl cinnamate, diethylene glycol diacetate, diethyl adipate, etc.; Examples of compounds having a carbonate structure with a boiling point of 250°C to 350°C include diphenyl carbonate, etc.; Examples of compounds having an amide structure with a boiling point of 250°C to 350°C include benzamide, N,N-dimethylbenzamide, and hexamethylenediamine; As the compound having a nitrile structure with a boiling point of 250°C to 350°C, there can be cited: adiponitrile, etc.; Examples of the compound having a sulfoxide structure with a boiling point of 250°C to 350°C include dibutylsulfoxide and diphenylsulfoxide; Examples of the compound having a sulfide structure with a boiling point of 250°C to 350°C include cyclobutane sulfide, 3-methylcyclobutane sulfide, dibutyl sulfide, benzenesulfonamide, and the like. Among these compounds, cyclobutanesulfonate and 3-methylcyclobutanesulfonate are more preferably used.

[0171] When a non-protonic polar substance with a boiling point of 250℃~350℃ is added alone or in combination with a solvent to a polyamide precursor, a resin having a polyamide precursor and a polyimide structure, or a solvent-soluble polyimide and then coated and cured (heated), the uniformity of the film thickness in the surface of the cured film can be improved and the YI can be reduced compared to the case where no addition is performed. The effect is particularly significant when 5 wt% or more is added when (mass of solvent + mass of non-protonic polar substance) is set to 100 wt%.

[0172] In the curing step of polyimide (heating to about 400°C), aprotic polar substances with a boiling point of 250°C to 350°C will remain in the film even if the temperature reaches 250°C or above, and play a role as a plasticizer at high temperature. Therefore, it is believed that in the temperature range of 250°C or above in the curing step, the resin becomes soft and fluid, the in-plane uniformity of the film thickness is improved, and the YI is also reduced. On the other hand, if the amount of aprotic polar substances with a boiling point of 250°C to 350°C is large, it cannot be completely volatilized during curing, and a small amount remains in the cured film. In the manufacturing step of flexible displays, CVD (Chemical Vapor Deposition) is sometimes used to form an inorganic film such as silicon nitride on the cured film, and a layer of amorphous silicon or low-temperature polycrystalline silicon is formed thereon, and the same temperature as the curing temperature is applied again (re-annealing step). If a non-protonic polar substance with a boiling point of 250℃~350℃ remains in the cured film, it will volatilize during re-annealing, causing the inorganic film formed on the film to bulge. In order to prevent this, the remaining amount of the substance in the film must be suppressed to less than 1000 ppm.

[0173] Therefore, the upper limit of the amount of the non-protonic polar substance added is 100 wt % when (mass of the solvent + mass of the non-protonic polar substance) is set to 100 wt % in the case of a polyimide precursor or a resin having a polyimide precursor skeleton and a polyimide skeleton. In the case of a solvent-soluble polyimide containing a solvent in addition to a polyimide precursor or a resin having a polyimide precursor skeleton and a polyimide skeleton, when (mass of the solvent + mass of the aprotic polar substance) is taken as 100 wt %, it is 50 wt %. In the case of a polyimide precursor, or a resin having a polyimide precursor skeleton and a polyimide skeleton, or a solvent-soluble polyimide, the addition amount is preferably 30 wt% or less.

[0174] Among the aprotic polar substances, cyclobutane sulfonate and 3-methylcyclobutane sulfonate have excellent effects of improving the in-plane uniformity of the cured film and reducing the YI. Although other substances also show the same effect, the effect is more significant when cyclobutane sulfonate and 3-methylcyclobutane sulfonate are used. When the boiling point of the aprotic polar substance is less than 250°C, the effect of improving the in-plane uniformity of the cured film and reducing the YI is not shown. When the boiling point exceeds 350°C, the effect is shown, but more than 1000 ppm remains in the cured film, which is not good from the viewpoint of degassing.

[0175] (Surfactant) By adding a surfactant to a resin composition, the coating properties of the resin composition can be improved. Specifically, the generation of streaks in the coating film can be prevented.

[0176] Examples of such surfactants include silicone surfactants, fluorine surfactants, and nonionic surfactants other than these. Examples of silicone surfactants include: organosiloxane polymers KF-640, 642, 643, KP341, X-70-092, X-70-093 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.); SH-28PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57, DC-190 (trade names, manufactured by Toray Dow Corning Silicone Co., Ltd.); SILWET L-77, L-7001, FZ-2105, FZ-2120, FZ-2154, FZ-2164, FZ-2166, L-7604 (trade names, manufactured by Nippon Unicar Co., Ltd.); DBE-814, DBE-224, DBE-621, CMS-626, CMS-222, KF-352A, KF-354L, KF-355A, KF-6020, DBE-821, DBE-712 (Gelest), BYK-307, BYK-310, BYK-378, BYK-333 (trade name, BYK-Chemie Japan); Glanol (trade name, Kyoeisha Chemical Co., Ltd.). Examples of fluorine-based surfactants include MEGAFAC F171, F173, R-08 (trade name, Dainippon Ink & Chemicals Co., Ltd.); Fluorad FC4430, FC4432 (trade name, Sumitomo 3M Co., Ltd.). Examples of nonionic surfactants other than these include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether.

[0177] Among these surfactants, polysilicone-based surfactants and fluorine-based surfactants are preferred from the viewpoint of coating properties (striping suppression) of the resin composition, and polysilicone-based surfactants are preferred from the viewpoint of reducing the YI value based on oxygen concentration during the curing step and the influence on the total light transmittance. When a surfactant is used, its blending amount is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the polyimide precursor in the resin composition.

[0178] (Alkoxysilane compounds) When the polyimide film obtained from the resin composition is used for a flexible substrate or the like, the resin composition may contain 0.01 to 20 parts by mass of an alkoxysilane compound relative to 100 parts by mass of a polyimide precursor from the viewpoint of obtaining good adhesion between the support and the polyimide film in the manufacturing process. By making the content of the alkoxysilane compound 0.01 parts by mass or more relative to 100 parts by mass of the polyimide precursor, good adhesion between the support and the polyimide film can be obtained. In addition, from the viewpoint of the storage stability of the resin composition, it is preferred that the content of the alkoxysilane compound is 20 parts by mass or less. The content of the alkoxysilane compound is preferably 0.02 to 15 parts by mass, more preferably 0.05 to 10 parts by mass, and further preferably 0.1 to 8 parts by mass relative to 100 parts by mass of the polyimide precursor. By using an alkoxysilane compound, in addition to the improvement of the above-mentioned adhesion, the coating property of the resin composition can also be improved (suppression of streaks), and the influence of the oxygen concentration on the YI value of the polyimide film during curing can be reduced.

[0179] Examples of the alkoxysilane compound include 3-ureidopropyltriethoxysilane, bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane, γ-aminoethyltriethoxysilane, γ-aminoethyltripropoxysilane, γ-aminoethyl Tributoxysilane, γ-aminobutyltriethoxysilane, γ-aminobutyltrimethoxysilane, γ-aminobutyltripropoxysilane, γ-aminobutyltributoxysilane, phenylsilanetriol, trimethoxyphenylsilane, trimethoxy(p-tolyl)silane, diphenylsilanediol, dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol, and the following structure: [Chemistry 76] The alkoxysilane compounds represented by each of the above are used. The alkoxysilane compounds may be used alone or in combination of two or more.

[0180] [Production method of polyamide-imide copolymer] The polyamine, polyimide, and polyamine-imide copolymer of the present invention can be synthesized by a production method comprising the following steps. For example, the production method of the polyamine-imide copolymer has the following steps 1 to 3: Step 1: a step of reacting the tetracarboxylic dianhydride component (X3) and the diamine component (X4) constituting the polyimide portion of the general formula (1) to obtain a solvent-soluble polyimide solution; Step 2: dissolving the diamine (X2) of the polyamide portion of the general formula (1) in the polyimide obtained in step 1; and Step 3: A step of reacting the tetracarboxylic dianhydride component (X1) constituting the polyamide portion of the general formula (1) with the solution obtained in step 2 to obtain a polyamide-imide copolymer.

[0181] First, the specific implementation methods are described in order from step 1. Step 1 is a step of synthesizing the polyimide part in the general formula (1). It can be synthesized by subjecting the diamine (e.g., 44BAFL) of the polyimide part in the general formula (1) to polycondensation reaction with tetracarboxylic dianhydride (e.g., BPAF). The reaction is preferably carried out in a reaction vessel from which water generated during imidization is removed, and in a solvent that can dissolve the monomer and the polyimide to be purified. Specifically, for example, the following method can be cited: a specific amount of BAFL and NMP are added to a separable flask equipped with a reflux tube and a Dean-Stark tube, and after BAFL is completely dissolved, a specific amount of BPAF and toluene as an azeotropic solvent for water are added, and the mixture is heated to 180° C. and stirred. The water generated during heating at 180° C. and toluene as an azeotropic solvent are preferably appropriately discharged to the outside of the container.

[0182] From the viewpoint of controlling the thermal linear expansion coefficient, residual stress, elongation, and yellowness (hereinafter, also referred to as YI) of the obtained resin film within the desired range, the ratio (molar ratio) of the tetracarboxylic dianhydride component to the diamine component when synthesizing the above-mentioned polyimide precursor is preferably set to the range of tetracarboxylic dianhydride: diamine = 100:85 to 100:200 (0.85 to 2.00 moles of diamine per 1 mole of tetracarboxylic dianhydride), and more preferably set to the range of 100:101 to 100:125 (1.01 to 1.25 moles of diamine per 1 mole of acid dianhydride). By setting it to the above range, it is easy to react with polyamide acid, and the haze (Haze value) is reduced, which is preferred in this regard.

[0183] The reaction temperature is preferably 140° C. or higher, more preferably 160° C., from the viewpoint of achieving imidization and water removal at the same time. Furthermore, from the viewpoint of suppressing coloration due to decomposition of the solvent and reaction with the monomer, the reaction temperature is preferably 200° C. or lower, more preferably 190° C. or lower, and it is preferred that the temperature be quickly reduced to 100° C. or lower after the reaction is completed.

[0184] The reaction time is preferably 2 hours or more, more preferably 3 hours or more, from the viewpoint of increasing the molecular weight. On the other hand, from the viewpoint of suppressing coloration due to decomposition of the solvent and reaction with the monomer, the reaction time is preferably 12 hours or less, more preferably 6 hours or less.

[0185] Next, step 2 is described. Step 2 is a step of dissolving the diamine (X2) of the polyamide portion in the general formula (1) in the polyimide obtained in step 1. After the polyimide is synthesized in step 1, a specific amount of diamine (e.g., APAB) and NMP are added and stirred sufficiently to dissolve the diamine. From the viewpoint of controlling the thermal linear expansion coefficient, residual stress, elongation, and yellowness (hereinafter, also referred to as YI) of the finally obtained polyimide copolymer film within the desired range, it is preferred that the ratio of the component (X3) derived from the tetracarboxylic dianhydride of the polyimide portion: the components (X2 and X4) derived from the diamine components of the polyimide portion and the polyamide portion be 100:150 to 100:3000 (1.50 to 30 mol parts of diamine per 1 mol part of tetracarboxylic dianhydride), more preferably 100:225 to 100:2000 (2.25 to 20 mol parts of diamine per 1 mol part of tetracarboxylic dianhydride), and the molar ratio (diamine / tetracarboxylic dianhydride) is further preferably 2.25 to 20. By setting the above range, the reaction uniformity of the tetracarboxylic dianhydride reaction in step 3 is improved, the molecular weight distribution is close to 2.00, and a polyamide-imide copolymer having a low ratio of oligomers with a molecular weight of less than 1,000 is obtained, and the thermal stability in the high temperature region when the film is made is improved.

[0186] The temperature for dissolving the diamine is preferably 40° C. or higher, more preferably 60° C. or higher, from the viewpoint of improving the solubility of the diamine and improving the uniformity. On the other hand, from the viewpoint of suppressing coloration due to a side reaction with the solvent, it is preferably 120° C. or lower, more preferably 100° C. or lower.

[0187] Next, step 3 is described. In step 3, the tetracarboxylic dianhydride of the polyamide portion of the general formula (1) is added to the solution containing the polyimide and the diamine in step 2 to carry out a polycondensation reaction to synthesize the polyamide-imide copolymer.

[0188] As a method for producing a polyamide-imide copolymer including a step different from the above steps 1 to 3, a method described in the handbook of International Publication No. 2020 / 138360 is known. Specifically, in the imidization step of the above step 1, a step of simultaneously imidizing the diamine compounds corresponding to X2 and X4 may be included, and a diamine compound common to X2 and X4 may be used.

[0189] However, according to the results confirmed by the inventors, when the same production method as that of International Publication No. 2020 / 138360 is used, that is, when the diamine corresponding to the general formula (B-1) or (B-2) is used as a raw material in the synthesis of the imide in step 1, the molecular weight is not sufficiently increased, and a polyamide-imide copolymer that can be evaluated cannot be obtained. The reason is believed to be that the diamine represented by the general formula (B-1) and (B-2) has high reactivity and lacks thermal stability in high-temperature solvents. If the amine is heated at a high temperature (about 180°C) in a state of excess relative to the acid, the diamine will react with the solvent or oxygen, etc. and become inactivated, and the molecular weight will not be sufficiently increased when the polyamide-imide copolymer is synthesized in the subsequent step.

[0190] Specifically, a polyimide-polyamide copolymer NMP solution (hereinafter also referred to as varnish) was obtained by performing a reproduction test under the same conditions as the examples in the handbook of International Publication No. 2020 / 138360. As a result, it was confirmed that the weight average molecular weight (Mw) of the obtained polyamide-amide copolymer was 2,638 and the number average molecular weight (Mn) was 1,326. Therefore, from the perspective of the molecular weight of the copolymer, the production method including the above steps 1 to 3 is better than the production method described in the handbook of International Publication No. 2020 / 138360.

[0191] From the viewpoint of controlling the thermal linear expansion coefficient, residual stress, elongation, and YI of the obtained resin film within the desired range, the molar ratio (X2 / X1) of the tetracarboxylic dianhydride component (X1) and the diamine component (X2) of the polyamide part when synthesizing the above-mentioned polyamide-imide copolymer is preferably 0.85-1.2, more preferably 0.90-1.1, and further preferably 0.92-1.00. By setting it in the above range, it is easy to react with polyimide, and the haze (Haze value) is reduced, which is preferred in this regard.

[0192] In addition, from the viewpoint of controlling the thermal linear expansion coefficient, residual stress, elongation, and YI of the obtained resin film within the desired range, the molar ratio (X4 / X3) of the tetracarboxylic dianhydride component (X3) and the diamine component (X4) of the polyimide portion when synthesizing the above-mentioned polyamide-imide copolymer is preferably in the range of 0.85 to 2.0, more preferably in the range of 0.95 to 1.5, and further preferably in the range of 1.01 to 1.25. By setting it in the above range, the heat resistance at high temperature is improved, the decomposition reaction during heating is suppressed, and the yellowness (YI value) and haze (Haze value) are reduced, which is preferred in this respect.

[0193] In addition, from the viewpoint of controlling the thermal linear expansion coefficient, residual stress, elongation, and YI of the obtained resin film within the desired range, the molar ratio ((molar number of X2+molar number of X4) / (molar number of X1+molar number of X3)) of the tetracarboxylic dianhydride component (X1 and X3) and the diamine component (X2 and X4) of the polyamide and polyimide parts when synthesizing the above-mentioned polyamide-imide copolymer is preferably set to the range of 0.92 to 1.05, and more preferably to the range of 0.94 to 1.00. By setting it to the above range, the molecular weight of the polyamide-imide copolymer is easily increased, the processability as a resin composition is improved, the coating unevenness during film production can be suppressed, and the haze (Haze value) is reduced, which is preferred from this viewpoint. Furthermore, within the above range, the end-capping amine of the polyamide-imide copolymer is reduced, the decomposition reaction during heating is suppressed, the thermal stability in the high temperature region is improved, and the yellowness (YI value) is reduced.

[0194] When synthesizing polyamide-imide copolymers, the molecular weight can be controlled by adjusting the ratio of tetracarboxylic dianhydride components to diamine components and adding end-capping sealants. The closer the ratio of dianhydride components to diamine components is to 1:1 and the less end-capping sealant is used, the greater the molecular weight of the polyimide can be.

[0195] As the tetracarboxylic dianhydride component and the diamine component, it is recommended to use high-purity products. As for the purity, it is preferably set to 98 mass % or more, more preferably to 99 mass % or more, and further preferably to 99.5 mass % or more. When multiple acid dianhydride components or diamine components are used in combination, it is sufficient as long as the acid dianhydride component or diamine component as a whole has the above purity, but it is preferred that all types of acid dianhydride components and diamine components used have the above purity.

[0196] As the solvent for the reaction, the solvents listed in the above-mentioned (d) organic solvent can be used without limitation.

[0197] As other components, the compounds described in the above (e) imidization catalyst can be used without limitation.

[0198] The boiling point of the solvent used in the synthesis of polyimide at normal pressure is preferably 60°C to 300°C, more preferably 140°C to 280°C, and particularly preferably 170°C to 270°C. If the boiling point of the solvent is higher than 300°C, the drying step requires a long time. On the other hand, if the boiling point of the solvent is lower than 60°C, the surface of the resin film may become uneven during the drying step, bubbles may be mixed into the resin film, and a uniform film may not be obtained.

[0199] As described above, it is preferred that the boiling point of the solvent under normal pressure is 170°C to 270°C. From the viewpoint of solubility and edge shrinkage during coating, it is more preferred to use a solvent having a vapor pressure of 250 Pa or less at 20°C. More specifically, it is preferred to use one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF). The solvents described in the above item "(d) Organic solvent" can be used appropriately. The water content in the solvent is preferably 3000 mass ppm or less. These solvents can be used alone or in combination of two or more.

[0200] [Production method of polyamine] The polyamine of the fourth embodiment of the present invention is not limited, and can be produced, for example, by the method described in the handbook of International Publication No. 2017 / 051827.

[0201] <Polyimide copolymer> As another aspect of the present invention, a film comprising a polyimide copolymer obtained by imidizing the polyamide-imide copolymer (c) contained in the above resin composition is provided. More specifically, a polyimide copolymer can be provided, characterized in that it comprises the following general formula (2): [Chemistry 77] {wherein, X1 and X3 represent a tetravalent organic group, X2 and X4 represent a divalent organic group, and n and m are positive integers} The structural unit represented by the above general formula (A-1) or the above general formula (A-2) has a structure represented by X2.

[0202] The polyimide copolymer preferably satisfies any of the following conditions from the viewpoint that the polyimide film containing the polyimide copolymer has excellent transparency, haze, heat resistance and linear expansion coefficient: The diamine component constituting X2 in the general formula (2) is a compound in which two * in the structure represented by the above general formula (A-1) or the above general formula (A-2) are replaced by -NH2; · X 3 in the general formula (2) is selected from at least one of the structures represented by the general formula (A-3), structures derived from ODPA, and structures derived from 6FDA; · X 1 in the general formula (2) is selected from at least one of the group consisting of a structure derived from BPDA, a structure derived from ODPA, and a structure derived from TAHQ; The molar ratio (X2 / X1) of X1 to X2 contained in the general formula (2) is 0.84 to 1.00; The molar ratio of X3 to X4 (X4 / X3) in the general formula (2) is 1.01 to 2.00; and The molar ratio of the structural unit of the polyimide comprising X1 and X2 in the general formula (2) to the structural unit of the polyimide comprising X3 and X4 (the molar number of the structural unit N: the molar number of the structural unit M) is in the range of 60:40 to 95:5; X1 or X3 is at least one selected from the group consisting of the structure represented by the above general formula (A-3), the structure derived from 4,4'-oxydiphthalic anhydride (ODPA), and the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA); X4 is at least one selected from the group consisting of the structures represented by the above-mentioned general formula (A-4), general formula (A-5) and general formula (A-6).

[0203] From the viewpoint that the polyimide film comprising the polyimide copolymer has excellent transparency, haze, heat resistance and linear expansion coefficient, it is preferred that when X2 in the general formula (2) is a group derived from 4-aminobenzoic acid 4-amino-3-fluorophenyl ester, the following structures 1 and 2 are excluded: Configuration 1. When X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), X 4 is a group derived from 4,4'-diaminodiphenylsulfone and / or 2,2'-bis(trifluoromethyl)benzidine; and The components 2.X 3 are derived from norfloxacin-2-spiro-α-cyclopentanone or α-α'-spiro-2''-norfloxacin-5,5'',6,6''-tetracarboxylic dianhydride.

[0204] From the viewpoint of transparency, heat resistance, low residual stress and bending resistance, the polyimide copolymer is preferably a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluoranhydride (BPAF), except that X4 in the general formula (2) is a group derived from 4,4'-diaminodiphenylsulfone or 2,2'-bis(trifluoromethyl)benzidine.

[0205] <Resin composition containing polyamide> As another aspect of the present invention, a resin composition is provided, characterized in that it comprises polyamide, the above-described (d) organic solvent and (e) imidization catalyst, wherein the polyamide comprises a structural unit represented by the following general formula (3): [Chemistry 78] {wherein, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer} The (e) imidization catalyst is an imidazole compound comprising N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and / or 1-methylimidazole, or the (e) imidization catalyst is an imidazole compound, and the content of the (e) imidization catalyst is 5 parts by mass or more relative to 100 parts by mass of the polyamide.

[0206] The resin composition containing the structural unit represented by the general formula (3) preferably contains N-tert-butyloxycarbonylimidazole (N-Boc-imidazole) and 1-methylimidazole as (e) imidization catalyst. In addition, the content of (e) imidization catalyst is preferably in the range of 0.02 to 0.15 relative to 1 mol of the repeating unit of the polyamide having the structural unit represented by the general formula (3).

[0207] X1, X2 and n in the general formula (3) may be defined as in the general formula (1) or (2) above. X1 is preferably at least one selected from the group consisting of the structure represented by the general formula (A-3) above, the structure derived from 4,4'-oxydiphthalic anhydride (ODPA), the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), the structure derived from biphenyltetracarboxylic anhydride (BPDA), and the structure derived from 4,4'-biphenylbis(trimellitic acid monoester anhydride) (TAHQ). X2 is preferably at least one selected from the group consisting of the structures represented by the general formula (A-1), the general formula (A-2), the general formula (A-4), the general formula (A-5), and the general formula (A-6), and more preferably the structure represented by the general formula (A-1).

[0208] The weight average molecular weight (Mw) of polyamide is preferably 2,639 or more, more preferably 2,639 to 300,000 or 10,000 to 300,000, further preferably 20,000 to 250,000, and particularly preferably 40,000 to 200,000. If the weight average molecular weight is 2,639 or more, mechanical properties such as elongation and breaking strength are excellent, residual stress is reduced, and YI is reduced. If the weight average molecular weight is 300,000 or less, the viscosity and concentration of the varnish containing polyamide are well balanced, the processability is good, and the film unevenness during coating is reduced. Furthermore, if the Mw of the polyamide is 170,000 or more, it tends to be excellent in transparency, haze, heat resistance and linear expansion coefficient, so it is preferred, and more preferably 220,000 or more. This tendency is significant when the structure represented by the above general formula (A-1) is used as X2 in the general formula (3). In the present invention, the weight average molecular weight is a value obtained using gel permeation chromatography (hereinafter, also referred to as GPC) as a standard polystyrene conversion value.

[0209] <Polyimide> As another aspect of the present invention, there is provided a compound comprising the following general formula (3): [Chemistry 79] {wherein, X 3 represents a tetravalent organic group, X 4 represents a divalent organic group, and m is a positive integer} The polyimide of the structural unit M represented by the formula (16) [Chemistry 80] {wherein, P1 and P2 are the same as P1 and P2 in general formula (I) or (II), and m is a positive integer} A polyimide of the structure represented.

[0210] The polyimide is characterized in that it contains at least one selected from the group consisting of the structure represented by the general formula (A-3) described above, the structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and the structure derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as X3 in the general formula (3).

[0211] X4 in the general formula (3) is as described for X4 in the general formula (1) or (2). From the same viewpoint as X4 in the general formula (1) or (2), the diamine component constituting X4 in the general formula (3) is preferably different in diamine composition or diamine type, and more preferably is an aromatic diamine composition or type, and further preferably X4 in the general formula (3) is at least one selected from the group consisting of the structures represented by the general formula (A-4), the general formula (A-5), and the general formula (A-6) described above.

[0212] Preferred P1 and P2 in the general formula (I) or (II) are also preferred in the polyimide of the general formula (16) for the same reason. The number m of repeating units in the general formula (16) is not particularly limited and can be an integer of 2 to 150.

[0213] Furthermore, it is preferred that the polyimide obtained from the resin composition substantially does not contain aprotic polar substances with a boiling point of 250° C. to 350° C. contained in the resin composition, but may contain the aprotic polar substances in an amount of less than 1000 ppm.

[0214] 《Method for producing resin composition》 The method for producing the resin composition described above is not particularly limited, and for example, the following method may be used.

[0215] <Purification of Silicon-Containing Compounds> The resin composition can be produced by subjecting a polycondensation component including an acid dianhydride, a diamine, and a silicon-containing compound to a polycondensation reaction. As a method for reducing the total amount of the cyclic silicon-containing compound contained in the resin composition, for example, the silicon-containing compound can be purified before the polycondensation reaction to reduce the total amount of the cyclic silicon-containing compound. Alternatively, the resin composition can be purified after the polycondensation reaction to reduce the total amount of the cyclic silicon-containing compound.

[0216] As a method for purifying the silicon-containing compound, for example, an inert gas, such as nitrogen, is blown toward the silicon-containing compound in any container while performing stripping. The stripping temperature is preferably 200°C or higher and 300°C or lower, more preferably 220°C or higher and 300°C or lower, and further preferably 240°C or higher and 300°C or lower. The steam pressure of the stripping is preferably as low as possible, and is 1000 Pa or lower, more preferably 300 Pa or lower, further preferably 200 Pa or lower, and further preferably 133.32 Pa (1 mmHg) Pa or lower. The stripping time is preferably 4 hours or higher and 12 hours or lower, and further preferably 6 hours or higher and 10 hours or lower. By adjusting to the above conditions, a cyclic silicon-containing compound can be efficiently removed, and the total amount of the cyclic silicon-containing compound can be controlled within a preferred range.

[0217] <Synthesis of Polyimide / Polyimide Precursor> The polyimide precursor can be synthesized by subjecting the polycondensation components including acid dianhydride, diamine, and silicon-containing compound to a polycondensation reaction. Regarding the synthesis of polyimide / polyimide precursor, for example, a method for manufacturing a resin composition comprising any of the following steps is provided: · A step of subjecting at least one compound selected from the above-mentioned diamine compounds, at least one compound selected from the above-mentioned dianhydride compounds, and other compounds to a polycondensation reaction to provide a polyimide precursor and / or a polyimide; A step of subjecting at least one compound selected from the above diamine compounds, at least one compound selected from the above dianhydride compounds, the silicon-containing compound represented by the general formula (13), and other compounds to a polycondensation reaction to provide a polyimide precursor and / or a polyimide. In addition, the silicon-containing compound is preferably purified as described above. In a preferred embodiment, the polycondensation component comprises an acid dianhydride, a diamine, and a silicon-containing compound. The polycondensation reaction is preferably carried out in an appropriate solvent. Specifically, for example, the following method can be cited: after dissolving a specific amount of a diamine component and a silicon-containing compound in a solvent, a specific amount of an acid dianhydride is added to the obtained diamine solution and stirred. The imidization during the synthesis of polyimide can be thermal imidization or chemical imidization using an imidization catalyst.

[0218] From the viewpoint of increasing the molecular weight of the polyimide precursor resin and the slit coating properties of the resin composition, the molar ratio of the acid dianhydride to the diamine when synthesizing the polyimide / polyimide precursor is preferably in the range of acid dianhydride:diamine = 100:90 to 100:110 (0.90 to 1.10 moles of diamine per 1 mole of acid dianhydride), and more preferably in the range of 100:95 to 100:105 (0.95 to 1.05 moles of diamine per 1 mole of acid dianhydride).

[0219] The molecular weight of polyimide / polyimide precursor can be controlled by the types of dianhydride, diamine and silicon-containing compound, the adjustment of the molar ratio of dianhydride to diamine, the addition of end-capping sealant, the adjustment of reaction conditions, etc. The closer the molar ratio of dianhydride component to diamine component is to 1:1, and the less the amount of end-capping sealant used, the higher the molecular weight of the polyimide precursor can be.

[0220] It is recommended to use high-purity products as the acid dianhydride component and the diamine component. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and further preferably 99.5% by mass or more. It can also be highly purified by reducing the water content in the acid dianhydride component and the diamine component. When using multiple acid dianhydride components and / or multiple diamine components, it is preferred that the acid dianhydride component as a whole and the diamine component as a whole have the above purity, and it is more preferred that all types of acid dianhydride components and diamine components used have the above purity.

[0221] The solvent for the reaction is not particularly limited, as long as it can dissolve the acid dianhydride component and the diamine component, and the generated polyimide / polyimide precursor to obtain a high molecular weight polymer. Examples of such solvents include aprotic solvents, phenolic solvents, ethers, and glycol solvents.

[0222] Examples of aprotic solvents include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, and amide solvents of the following general formula: [Chemistry 81] {wherein, Equamide M100 represented by R 12 = methyl (trade name: manufactured by KJ CHEMICALS Co., Ltd.), and Equamide B100 represented by R 12 = n-butyl (trade name: manufactured by KJ CHEMICALS Co., Ltd.)}; lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphatiamide and hexamethylphosphinetriamide; sulfur-containing solvents such as dimethyl sulfone, dimethylsulfoxide and cyclobutanesulfone; ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; ester solvents such as acetic acid (2-methoxy-1-methylethyl), etc.

[0223] Examples of the phenolic solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol and 3,5-xylenol.

[0224] Examples of the ether and glycol solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, and 1,4-dioxane.

[0225] These solvents may be used alone or in combination of two or more.

[0226] The boiling point of the solvent used in the synthesis of polyimide / polyimide precursor is preferably 60-300°C, more preferably 140-280°C, and further preferably 170-270°C at normal pressure. By making the boiling point of the solvent lower than 300°C, the drying step time is shorter. If the boiling point of the solvent is 60°C or higher, it is less likely to produce unevenness on the surface of the resin film, bubbles mixed into the resin film, etc. during the drying step, and a more uniform film can be obtained. From the viewpoint of reducing solubility and edge abnormalities during coating, it is particularly preferred to use a solvent with a boiling point of 170-270°C and / or a vapor pressure of 250 Pa or less at 20°C. More specifically, it is preferably one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and the compound represented by the above general formula.

[0227] In order to make the polycondensation reaction proceed well, the water content in the solvent is preferably 3,000 mass ppm or less. In the resin composition, the content of molecules with a molecular weight of less than 1,000 is preferably less than 5 mass%. It is believed that the presence of molecules with a molecular weight of less than 1,000 in the resin composition is related to the water content of the solvent or raw materials (acid dianhydride, diamine) used in the synthesis. That is, it is believed that the acid anhydride groups of a part of the acid dianhydride monomers are hydrolyzed by water to become carboxyl groups, and they are not high molecular weight but remain in a low molecular state. Therefore, the less water content of the solvent used in the above-mentioned polycondensation reaction, the better. The water content of the solvent is preferably set to 3,000 mass ppm or less, and more preferably to 1,000 mass ppm or less. Similarly, regarding the water content contained in the raw materials, it is preferably set to 3,000 mass ppm or less, and more preferably to 1,000 mass ppm or less.

[0228] The water content of the solvent is believed to be related to the grade of the solvent used (dehydrated grade, general grade, etc.), the solvent container (bottle, 18L can, barrel, etc.), the storage status of the solvent (whether or not a rare gas is sealed), the time from opening to use (use immediately after opening or use after a period of time after opening, etc.). It is also believed to be related to the rare gas replacement of the reactor before synthesis, the presence or absence of rare gas circulation during synthesis, etc. Therefore, when synthesizing polyimide precursors, it is recommended to use high-purity products as raw materials, use solvents with less water content, and adopt treatments that prevent moisture from the environment from mixing into the system before and during the reaction.

[0229] When each polycondensation component is dissolved in the solvent, heating may be performed as needed. From the perspective of obtaining a polyimide precursor with a high degree of polymerization, the reaction temperature during the synthesis of the polyimide precursor may preferably be 0°C to 120°C, 40°C to 100°C, or 60°C to 100°C, and the polymerization time may preferably be 1 to 100 hours or 2 to 10 hours. By setting the polymerization time to more than 1 hour, a polyimide precursor with a uniform degree of polymerization can be obtained, and by setting it to less than 100 hours, a polyimide precursor with a high degree of polymerization can be obtained.

[0230] The resin composition may contain other additional polyimide precursors in addition to the polyimide / polyimide precursor described above. However, from the viewpoint of reducing the oxygen dependence of the YI value and total light transmittance of the polyimide film, the mass ratio of the additional polyimide / polyimide precursor relative to the total amount of the polyimide / polyimide precursor in the resin composition is preferably 30% by mass or less, and further preferably 10% by mass or less.

[0231] The polyimide precursor may also be partially imidized (partially imidized). By partially imidizing the polyimide precursor, the viscosity stability of the resin composition during storage can be improved. From the perspective of obtaining a balance between the solubility of the polyimide precursor in the resin composition and the storage stability of the solution, the imidization rate in this case is preferably 5% or more, more preferably 8% or more, preferably 80% or less, more preferably 70% or less, and further preferably 50% or less. The partial imidization can be obtained by heating the polyimide precursor to dehydrate and close the ring. The heating can be performed at a temperature of preferably 120-200°C, more preferably 150-185°C, and further preferably 150-180°C, preferably for 15 minutes to 20 hours, and more preferably 30 minutes to 10 hours.

[0232] The polyimide / polyimide precursor obtained by the above reaction can be obtained by adding N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal and heating to esterify part or all of the carboxylic acid. The viscosity stability during storage can be improved by esterification. The ester-modified polyamide acid can also be obtained by reacting the above-mentioned acid dianhydride component with a monohydric alcohol in an equivalent amount relative to the acid anhydride group, and a dehydration condensation agent such as sulfinyl chloride and dicyclohexylcarbodiimide in sequence, and then condensing with a diamine component.

[0233] <Synthesis of Polyimide> As a more preferred aspect, the polyimide varnish can be prepared by dissolving the dianhydride component and the diamine component in a solvent, such as an organic solvent, adding an azeotropic solvent such as toluene, and removing the water generated during imidization to the outside of the system, thereby preparing a polyimide solution (also called a polyimide varnish) containing polyimide and a solvent. Here, the reaction conditions are not particularly limited, for example, the reaction temperature is 0°C to 180°C, and the reaction time is 3 to 72 hours. In order to fully react with the sulfonyl-containing diamines, it is preferred to heat the reaction at 180°C for about 12 hours. In addition, the reaction is preferably carried out in an inert atmosphere such as argon or nitrogen.

[0234] <Preparation of resin composition> When the solvent used in synthesizing the polyimide precursor is the same as the solvent contained in the resin composition, the synthesized polyimide / polyimide precursor solution can be directly used as the resin composition. It is also possible to further add one or more solvents and additional components to the polyimide precursor at a temperature range of room temperature (25°C) to 80°C, and stir and mix to prepare the resin composition. The stirring and mixing can be carried out using a suitable device such as a Sany motor (manufactured by Shinto Chemical Co., Ltd.) with stirring wings, a rotation and revolution mixer, etc. The resin composition can also be heated to 40°C to 100°C as needed.

[0235] On the other hand, when the solvent used in synthesizing the polyimide / polyimide precursor is different from the solvent contained in the resin composition, the solvent in the synthesized polyimide precursor solution can be removed by appropriate methods such as reprecipitation and solvent distillation to isolate the polyimide / polyimide precursor. Then, the required solvent and additional components can be added to the isolated polyimide precursor at a temperature range of room temperature (25° C.) to 80° C., and stirred and mixed to prepare the resin composition.

[0236] It is particularly preferred that in the preparation of the resin composition, after the synthesis of the polyimide / polyimide precursor, the non-protonic polar substance with a boiling point of 250°C to 350°C is finally added. This can improve the in-plane uniformity of the film thickness of the obtained polyimide resin film and also reduce the yellowness (YI value).

[0237] After the resin composition is prepared in the above manner, the resin composition is heated at 130-200° C. for 5 minutes to 2 hours, for example, to dehydrate and imidize a portion of the polyimide precursor to a degree that the polymer does not precipitate (partial imidization). The imidization rate can be controlled by controlling the heating temperature and the heating time. By partially imidizing the polyimide precursor, the viscosity stability of the resin composition during storage can be improved.

[0238] From the perspective of slit coating performance, the solution viscosity of the resin composition is preferably 500 to 100,000 mPa·s, more preferably 1,000 to 50,000 mPa·s, and further preferably 3,000 to 20,000 mPa·s. Specifically, from the perspective of preventing leakage from the slit nozzle, it is preferably 500 mPa·s or more, more preferably 1,000 mPa·s or more, and further preferably 3,000 mPa·s or more. From the perspective of preventing clogging of the slit nozzle, it is preferably 100,000 mPa·s or less, more preferably 50,000 mPa·s or less, and further preferably 20,000 mPa·s or less.

[0239] Regarding the solution viscosity of the resin composition during the synthesis of polyimide / polyimide precursor, if it is higher than 200,000 mPa·s, there is a risk that stirring during the synthesis may become difficult. However, even if the solution becomes highly viscous during the synthesis, a resin composition with good workability can be obtained by adding a solvent and stirring after the reaction is completed. The solution viscosity of the resin composition is a value measured at 23°C using an E-type viscometer (e.g., VISCONICE HD, manufactured by Toki Sangyo).

[0240] From the viewpoint of viscosity stability during storage of the resin composition, the water content of the resin composition is preferably 3,000 mass ppm or less, more preferably 2,500 mass ppm or less, further preferably 2,000 mass ppm or less, further preferably 1,500 mass ppm or less, particularly preferably 1,000 mass ppm or less, particularly preferably 500 mass ppm or less, particularly preferably 300 mass ppm or less, and particularly preferably 100 mass ppm or less.

[0241] 《Polyimide resin film and method for producing the same》 The resin composition described above can be used to provide a polyimide resin film (hereinafter, also referred to as a polyimide film). The method for producing the polyimide film described above includes: a coating step of coating the resin composition on the surface of a support; a film forming step of heating the resin composition to form a polyimide resin film; and a peeling step of peeling the polyimide resin film from the support.

[0242] <Coating Step> In the coating step, the resin composition is coated on the surface of the support. The support is not particularly limited as long as it is heat-resistant to the heating temperature in the subsequent film forming step (heating step) and has good peeling properties in the peeling step. Examples of the support include: glass substrates, such as alkali-free glass substrates; silicon wafers; resin substrates such as PET (polyethylene terephthalate), OPP (extended polypropylene), polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyamide imide, polyetherimide, polyetheretherketone, polyethersulfone, polyphenylenesulfone, polyphenylene sulfide; metal substrates such as stainless steel, alumina, copper, nickel, etc.

[0243] When a thin film polyimide molded body is formed, for example, a glass substrate, a silicon wafer, etc. are preferred. When a thick film or sheet polyimide molded body is formed, for example, a support body comprising PET (polyethylene terephthalate), OPP (oriented polypropylene), etc. is preferred.

[0244] As coating methods, generally, there can be cited: coating methods such as knife coaters, air knife coaters, roll coaters, spin coaters, flow coaters, die coaters, rod coaters, etc.; coating methods such as spin coating, spray coating, dip coating, etc.; printing technologies represented by screen printing and gravure printing, etc. For the resin composition, it is preferred to coat by slit coating. The coating thickness should be appropriately adjusted according to the desired thickness of the resin film and the content of the polyimide precursor in the resin composition, preferably about 1 to 1,000 μm. The temperature in the coating step can be room temperature. In order to reduce the viscosity and make the workability good, the resin composition can also be heated to, for example, 40°C to 80°C.

[0245] <Optional Drying Step> The drying step may be performed after the coating step, or the drying step may be omitted and the subsequent film forming step (heating step) may be directly performed. The drying step is performed to remove the organic solvent in the resin composition. When performing the drying step, for example, a suitable device such as a heating plate, a box-type dryer, a conveyor belt-type dryer, etc. may be used. The temperature of the drying step is preferably 80°C to 200°C, more preferably 100°C to 150°C. The implementation time of the drying step is preferably 1 minute to 10 hours, more preferably 3 minutes to 1 hour. As described above, a coating film containing a polyimide precursor is formed on a support.

[0246] <Film Formation Step> Then, a film forming step (heating step) is performed. The heating step is a step for removing the organic solvent contained in the above-mentioned coating film and promoting the imidization reaction of the polyimide precursor in the coating film to obtain a polyimide resin film. The heating step can be performed using an inert gas oven, a heating plate, a box-type dryer, a conveyor belt-type dryer, etc. This step can be performed simultaneously with the drying step, or the two steps can be performed one by one.

[0247] The heating step can be performed in an air atmosphere, but from the perspective of obtaining safety, good transparency of the obtained polyimide film, lower thickness direction retardation (Rth) and lower YI value, it is preferably performed in an inert gas atmosphere. As an inert gas, for example, nitrogen, argon, etc. can be cited. The heating temperature is appropriately set according to the type of polyimide precursor and the type of solvent in the resin composition, preferably 250°C to 550°C, and more preferably 300°C to 450°C. If it is above 250°C, the imidization proceeds well, and if it is below 550°C, the undesirable conditions such as reduced transparency and deterioration of heat resistance of the obtained polyimide film can be avoided. The heating time is preferably about 0.1 hours to 10 hours.

[0248] In particular, when the resin composition contains a non-protonic polar substance with a boiling point of 250°C to 350°C, it will remain in the film even at a temperature of 250°C or higher during the heating step of the polyimide and function as a plasticizer at high temperatures. As a result, the resin becomes soft and fluid, and as a result, the in-plane uniformity of the film thickness of the obtained polyimide resin film is improved, and the YI is also reduced.

[0249] From the viewpoint of transparency and YI value of the obtained polyimide film, the oxygen concentration of the surrounding atmosphere in the above-mentioned heating step is preferably 2,000 mass ppm or less, more preferably 100 mass ppm or less, and further preferably 10 mass ppm or less. By heating in an atmosphere with an oxygen concentration of 2,000 mass ppm or less, the YI value of the obtained polyimide film can be made 30 or less.

[0250] <Peeling Step> In the peeling step, the polyimide resin film on the support is cooled to, for example, room temperature (25° C.) to about 50° C. and then peeled off. The peeling step may be, for example, the following (1) to (4).

[0251] (1) After a structure including a polyimide resin film / support is prepared by the above method, a laser is irradiated from the support side of the structure to perform a stripping process on the interface between the support and the polyimide resin film, thereby peeling off the polyimide resin. Examples of the type of laser include solid (YAG) lasers and gas (UV excimer) lasers. Preferably, a spectrum with a wavelength of 308 nm is used (see Japanese Patent Publication No. 2007-512568, Japanese Patent Publication No. 2012-511173, etc.).

[0252] (2) A method of forming a release layer on the support before coating the resin composition on the support, and then obtaining a structure comprising a polyimide resin film / release layer / support, and then releasing the polyimide resin film. Examples of the release layer include Parylene (registered trademark, manufactured by Japan Parylene Association Co., Ltd.) and tungsten oxide; and release agents such as vegetable oil-based, silicone-based, fluorine-based, and alkyd-based release agents can also be used (see Japanese Patent Publication No. 2010-067957, Japanese Patent Publication No. 2013-179306, etc.). This method (2) can also be used in combination with the laser irradiation of method (1).

[0253] (3) A method of obtaining a polyimide resin film by using an etchable metal substrate as a support to obtain a structure including a polyimide resin film / support, and then etching the metal with an etchant to obtain a polyimide resin film. As the metal, for example, copper (as a specific example, electrolytic copper foil "DFF" manufactured by Mitsui Mining & Smelting Co., Ltd.), aluminum, etc. can be used. As the etchant, ferric chloride, etc. can be used for copper, and dilute hydrochloric acid, etc. can be used for aluminum.

[0254] (4) After obtaining a structure comprising a polyimide resin film / support by the above method, an adhesive film is attached to the surface of the polyimide resin film, the adhesive film / polyimide resin film is separated from the support, and then the polyimide resin film is separated from the adhesive film.

[0255] Among these stripping methods, method (1) or (2) is preferred from the viewpoint of the refractive index difference between the front and back surfaces of the obtained polyimide resin film, the YI value and the elongation. From the viewpoint of the refractive index difference between the front and back surfaces of the obtained polyimide resin film, it is more preferred to perform a laser irradiation step from the support side before the stripping step in method (1). Furthermore, in method (3), when copper is used as the support, there is a tendency that the YI value of the obtained polyimide resin film increases and the elongation decreases. This is believed to be due to the influence of copper ions.

[0256] The thickness of the obtained polyimide film is not limited, but is preferably 1-200 μm, more preferably 5-100 μm.

[0257] <Polyimide film> In another aspect of the present invention, a polyimide film is provided, characterized in that: when measured with a film thickness of 10 μm, the tensile elastic modulus at 25° C. is greater than 6 GPa, the tensile elastic modulus at 350° C. is greater than 0.5 GPa, and the yellowness (YI value) is less than 12.

[0258] The polyimide film is preferably prepared using the polyamide-imide copolymer and / or the polyimide copolymer described above as a raw material. From the viewpoint of achieving a balance between transparency, heat resistance and linear expansion coefficient, the haze (Haze value) of the polyimide film is preferably less than 0.5%, and / or from the viewpoint of achieving a balance between Haze value, heat resistance and linear expansion coefficient, the change rate of yellowness (YI value) of the polyimide film when kept at 430° C. for 1 hour is preferably 20% or less.

[0259] The resin film produced by using the polyamide-imide copolymer, polyamide, polyimide, and resin composition described above can be used as, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc., and can also be used as a substrate in the manufacture of a flexible device. Here, as flexible devices to which the resin film and laminate can be applied, for example, there can be cited: a flexible display, a flexible solar cell, a flexible touch panel electrode substrate, a flexible lighting, a flexible battery, etc.

[0260] 《Application of polyimide membrane》 The polyimide film obtained from the resin composition described above can be used as, for example, a semiconductor insulating film, a thin film transistor liquid crystal display (TFT-LCD) insulating film, an electrode protective film, and can also be used as a transparent substrate for display devices such as liquid crystal displays, organic electroluminescent displays, field emission displays, and electronic paper.

[0261] In particular, polyimide films can be preferably used as thin film transistor (TFT) substrates, color filter substrates, touch panel substrates, and flexible substrates of transparent conductive films (ITO, Indium Thin Oxide (Indium Tin Oxide)) in the manufacture of flexible devices. Examples of flexible devices to which polyimide films can be applied include: TFT devices for flexible displays, flexible solar cells, flexible touch panels, flexible lighting, flexible batteries, flexible printed substrates, flexible color filters, and surface covers for smartphones.

[0262] The process of forming a TFT on a flexible substrate using a polyimide film is typically performed at a wide temperature range of 150° C. to 650° C. Specifically, when manufacturing a TFT device using amorphous silicon, a process temperature of 250° C. to 350° C. is usually required, and the polyimide film must be able to withstand this temperature, so specifically, a polymer structure having a glass transition temperature and a thermal decomposition starting temperature above the process temperature must be appropriately selected.

[0263] When manufacturing TFT devices using metal oxide semiconductors (IGZO, etc.), a process temperature of 320°C to 400°C is usually required. The polyimide film must be able to withstand this temperature, so a polymer structure with a glass transition temperature and a thermal decomposition starting temperature above the highest temperature of the TFT manufacturing process must be appropriately selected.

[0264] When manufacturing TFT devices using low temperature polysilicon (LTPS), a process temperature of 380°C to 520°C is usually required. The polyimide film must be able to withstand this temperature, so the glass transition temperature and thermal decomposition starting temperature above the highest temperature of the TFT manufacturing process must be appropriately selected. On the other hand, due to these thermal histories, the optical properties of the polyimide film (especially light transmittance, retardation characteristics and YI value) tend to decrease the more it is exposed to high temperature processes. However, the polyimide obtained from the polyimide precursor has good optical properties even after a thermal history.

[0265] Hereinafter, as an example of the use of the polyimide film, a method for producing a display and a laminate will be described.

[0266] <Manufacturing method of display> In one aspect of the present invention, a method for manufacturing a display includes: a coating step of coating a resin composition on the surface of a support; a film forming step of heating the resin composition to form a polyimide film (polyimide resin film); an element forming step of forming an element on the polyimide film; and a peeling step of peeling the polyimide film formed with the element from the support.

[0267] Manufacturing example of flexible organic EL display FIG. 1 is a schematic diagram showing the structure of a top-emitting flexible organic EL display as an example of a display according to one aspect of the present invention, which is located above the polyimide substrate. The organic EL structure 25 of FIG. 1 is described. For example, an organic EL element 250a that emits red light, an organic EL element 250b that emits green light, and an organic EL element 250c that emits blue light are arranged in a matrix as one unit, and the light-emitting region of each organic EL element is defined by a partition wall (dam) 251. Each organic EL element includes a lower electrode (anode) 252, a hole transport layer 253, a light-emitting layer 254, and an upper electrode (cathode) 255. On the lower layer 2a showing a CVD multi-layer film (multi-barrier layer) including silicon nitride (SiN) or silicon oxide (SiO), a plurality of TFTs 256 (selected from low temperature polycrystalline silicon (LTPS) or metal oxide semiconductor (IGZO, etc.)) for driving organic EL elements, an interlayer insulating film 258 having a contact hole 257, and a lower electrode 259 are provided. The organic EL element is sealed by a sealing substrate 2b, and a hollow portion 261 is formed between each organic EL element and the sealing substrate 2b.

[0268] The manufacturing steps of the flexible organic EL display include: a step of manufacturing a polyimide film on a glass substrate support, and manufacturing the organic EL substrate shown in FIG. 1 on the top thereof; a step of manufacturing a sealing substrate; an assembly step of bonding the two substrates; and a peeling step of peeling the organic EL display manufactured on the polyimide film from the glass substrate support. The organic EL substrate manufacturing step, the sealing substrate manufacturing step, and the assembly step can apply well-known manufacturing steps. The following is an example, but it is not limited to this. The peeling step is the same as the peeling step of the polyimide film.

[0269] For example, referring to FIG. 1 , first, a polyimide film is formed on a glass substrate support by the above method, and a multi-layer barrier layer (lower substrate 2a in FIG. 1 ) including a plurality of layers of silicon nitride (SiN) and silicon oxide (SiO) is formed on the upper portion thereof by CVD or sputtering, and a metal wiring layer for driving TFT is formed on the upper portion thereof using photoresist. An active buffer layer such as SiO is formed on the upper portion thereof by CVD, and a TFT device such as metal oxide semiconductor (IGZO) or low temperature polycrystalline silicon (LTPS) is formed on the upper portion thereof (TFT 256 in FIG. 1 ). After the TFT substrate for a flexible display is formed, an interlayer insulating film 258 having a contact hole 257 is formed by using a photosensitive acrylic resin or the like. An ITO film is formed by using a sputtering method or the like, and a lower electrode 259 is formed in a manner of forming a pair with the TFT.

[0270] Next, after forming a partition wall (bank) 251 using photosensitive polyimide or the like, a hole transport layer 253 and a light emitting layer 254 are formed in each space divided by the partition wall. An upper electrode (cathode) 255 is formed in such a manner as to cover the light emitting layer 254 and the partition wall (bank) 251. Thereafter, using a fine metal mask or the like as a mask, an organic EL material emitting red light (corresponding to the organic EL element 250a emitting red light in FIG. 1 ), an organic EL material emitting green light (corresponding to the organic EL element 250b emitting green light in FIG. 1 ), and an organic EL material emitting blue light (corresponding to the organic EL element 250c emitting blue light in FIG. 1 ) are evaporated by a known method, thereby manufacturing an organic EL substrate. The organic EL substrate is sealed with a sealing film or the like (sealing substrate 2b in FIG. 1 ), and the device above the polyimide substrate is peeled off from the glass substrate support by a known peeling method such as laser peeling, thereby making a top-emitting flexible organic EL display. When the polyimide of one aspect of the present invention is used, a transparent flexible organic EL display can be made. A bottom-emitting flexible organic EL display can also be made by a known method.

[0271] Manufacturing example of flexible liquid crystal display A polyimide film according to one aspect of the present invention can be used to make a flexible liquid crystal display. As a specific production method, a polyimide film is produced on a glass substrate support using the above method, and a TFT substrate including, for example, amorphous silicon, a metal oxide semiconductor (IGZO, etc.), and low-temperature polycrystalline silicon is produced using the above method. In addition, according to the coating step and film forming step of one aspect of the present invention, a polyimide film is produced on a glass substrate support, and a color filter glass substrate (CF substrate) having a polyimide film is produced according to a known method and using a color resist, etc. A sealing material including a thermosetting epoxy resin, etc. is applied to one of the TFT substrate and the CF substrate by screen printing into a frame-shaped pattern lacking a portion of a liquid crystal injection port, and spherical spacers having a diameter equivalent to the thickness of the liquid crystal layer and including plastic or silicon dioxide are dispersed on the other substrate.

[0272] Then, the TFT substrate and the CF substrate are bonded together to harden the sealing material. Next, the liquid crystal material is injected into the space surrounded by the TFT substrate, the CF substrate and the sealing material by decompression, a thermosetting resin is applied to the liquid crystal injection port, and the liquid crystal material is sealed by heating to form a liquid crystal layer. Finally, the glass substrate on the CF side and the glass substrate on the TFT side are peeled off at the interface between the polyimide film and the glass substrate by laser peeling, thereby making a flexible liquid crystal display.

[0273] <Method for manufacturing laminate> A method for manufacturing a laminate according to one aspect of the present invention comprises: a coating step of coating a resin composition on the surface of a support; a film forming step of heating the resin composition to form a polyimide film (polyimide resin film); and an element forming step of forming an element on the polyimide film.

[0274] As the elements in the laminate, those exemplified above regarding the production of flexible devices such as flexible displays can be cited. As the support, for example, a glass substrate can be used. The preferred specific order of the coating step and the film forming step is the same as that described in the above-mentioned method for producing the polyimide film. In the element forming step, the above-mentioned element is formed on the polyimide resin film as a flexible substrate formed on the support. Thereafter, the polyimide resin film on which the element is formed and the element can be peeled off from the support in an optional peeling step. Furthermore, a method for manufacturing a flexible device according to one aspect of the present invention includes manufacturing a laminate by the above-mentioned method for manufacturing a laminate.

[0275] Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be appropriately modified within the scope of the gist of the invention. [Example]

[0276] Hereinafter, the present invention will be described in further detail based on examples, but these are for illustrative purposes only and the scope of the present invention is not limited to the following examples.

[0277] Various evaluations in Examples and Comparative Examples were performed in the following manner.

[0278] <Determination of weight average molecular weight and number average molecular weight> The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions.

[0279] N,N-dimethylformamide (manufactured by Fuji Film Wako Pure Chemical Industries, for high performance liquid chromatography, prepared by adding and dissolving 24.8 mmol / L lithium bromide monohydrate (manufactured by Fuji Film Wako Pure Chemical Industries, purity 99.5%) and 63.2 mmol / L phosphoric acid (manufactured by Fuji Film Wako Pure Chemical Industries, for high performance liquid chromatography) was used as a solvent. The calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (Easical Type PS-1, manufactured by Agilent Technologies). Device: HLC-8220GPC (manufactured by Tosoh Corporation) Column: 2 pieces of Tsk gel Super HM-H (manufactured by Tosoh) Flow rate: 0.5 mL / min Column temperature: 40℃ Detector: UV-8220 (UV-VIS: ultraviolet visible absorptometer, manufactured by Tosoh Corporation)

[0280] <Evaluation of glass transition temperature (Tg)> The glass transition temperature (Tg) in the temperature range of 50-500°C was measured by thermomechanical analysis using a polyimide film cut into a size of 3 mm × 20 mm as a test piece. Using the (EXSTAR6000) manufactured by Seiko Instruments Inc. as a measuring device, the elongation of the test piece in the temperature range of 50-500°C was measured under the conditions of a tensile load of 49 mN, a heating rate of 10°C / min, and a nitrogen flow (flow rate of 100 mL / min). The glass transition temperature of the polyimide film (thickness 10 μm) was obtained from the inflection point of the obtained curve. If no inflection point appears in the range of 50-500°C, it is considered that the Tg is 500°C or above, and sometimes it is shown as "-" in the following table.

[0281] <Evaluation of residual stress> Each resin composition was applied by a spin coater on a 6-inch silicon wafer with a thickness of 625 μm ± 25 μm and a pre-measured "warpage amount", and pre-baked at 100°C for 7 minutes. After that, the oxygen concentration in the chamber was adjusted to be less than 10 mass ppm, and a heat curing treatment (curing treatment) was performed at 430°C for 1 hour to produce a silicon wafer with a polyimide resin film having a thickness of 10 μm after curing.

[0282] The amount of warpage of the wafer was measured using a residual stress measuring device (manufactured by Tencor Corporation, model name FLX-230), and the residual stress generated between the silicon wafer and the resin film was evaluated. S: Residual stress exceeds -5 MPa and is less than 15 MPa (residual stress evaluation is "excellent") A: Residual stress is more than 15 MPa and less than 25 MPa (residual stress evaluation is "good") B: Residual stress exceeds 25 MPa (residual stress evaluation is "poor")

[0283] <Evaluation of Yellowness (YI value) and Haze value> Each resin composition was applied to Eagle XG glass of 100 mm square (thickness 0.7 mm) by a spin coater and pre-baked at 80°C for 30 minutes. After that, the oxygen concentration in the chamber was adjusted to be 10 mass ppm or less, and a heat curing treatment (curing treatment) was performed at 430°C for 1 hour to prepare a glass substrate with a polyimide resin film having a thickness of 10 μm after curing. The yellowness (YI value) of the obtained glass substrate with polyimide was measured using a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd. and a D65 light source, and the haze (Haze value) was measured using a Spectrophotometer (CM-3600A) manufactured by Konica Minolta Co., Ltd. and a D65 light source. S: YI value is 8 or more and 12 or less (YI value evaluation "S") A: YI value is 12 or more and 15 or less (YI value evaluation "A") B: YI value is 15 or more (YI value evaluation "B") S: Haze value is less than 0.2% (Haze value evaluation "S") A: Haze value is more than 0.2% and less than 0.5% (Haze value rating "A") B: Haze value exceeds 0.5% (Haze value rating "B")

[0284] <Evaluation of bending resistance> Each resin composition was applied by a spin coater on a 6-inch silicon wafer with a thickness of 625 μm±25 μm and pre-baked at 100°C for 7 minutes. After that, the oxygen concentration in the chamber was adjusted to be 10 mass ppm or less, and a heat curing treatment (curing treatment) was performed at 430°C for 1 hour to prepare a silicon wafer with a polyimide resin film having a thickness of 10 μm after curing. The prepared sample was immersed in a 10 mass % hydrochloric acid aqueous solution for 1 day, and the polyimide resin film was peeled off from the silicon wafer. The peeled polyimide film was cut into a size of 15 mm×100 mm as a test piece.

[0285] Using a MIT-type repeated bending tester (MIT-DA, manufactured by Toyo Seiki), a 250 g load was applied to the prepared test piece, and a repeated bending test was performed 100,000 times back and forth under the conditions of a bending radius (R) of 2 mm, a bending angle of 135°, and a speed of 90 times / minute. After the test, the sample was removed from the device, and the one with no visual damage was evaluated as A, and the one with damage was evaluated as B.

[0286] <Evaluation of Storage Stability> The resin composition was stored at 23°C, and after one week, a glass substrate with a polyimide resin film was prepared using the same evaluation method as in <Evaluation of yellowness (YI value) and haze (Haze value)>. The glass substrate with a haze (Haze value) of 0.5% or less was evaluated as "A", and the glass substrate with a haze (Haze value) of 0.5% or more was evaluated as "B".

[0287] <Evaluation of elastic modulus> The elastic modulus was measured by thermomechanical analysis using a polyimide film cut into a size of 3 mm × 20 mm as a test piece. Using the measurement device (EXSTAR6000) manufactured by Seiko Instruments Inc., the set temperature was fixed at 25°C or 350°C, and the elongation was measured in a nitrogen atmosphere by applying a load from an initial tensile load of 20 mN and changing the load at a load change rate of 100 mN / min to a maximum of 1200 mN. The elastic modulus of the polyimide film (thickness 10 μm) was calculated from the slope of the obtained curve. Films that were fragile and broke during the measurement, or films that broke during the measurement due to a low Tg were evaluated as "B" in Table 4. The evaluation criteria are as follows. Elastic modulus at 25℃ S: Elastic modulus is 6 GPa or more (elastic modulus evaluation "S") B: YI value is less than 6 GPa (elastic modulus evaluation "B") Elastic modulus at 350℃ S: Elastic modulus is 0.5 GPa or more (elastic modulus evaluation "S") B: YI value is less than 0.5 GPa (elastic modulus evaluation "B")

[0288] <Sputtering reheating test> An aluminum (Al) film of about 100 nm was sputtered on the glass substrate with polyimide resin prepared in the same manner as in <Evaluation of yellowness (YI value) and haze value>. The Al film was formed on the polyimide film.

[0289] For the produced samples, adjust them so that the oxygen concentration in the storage reaches 10 mass ppm or less, and perform a heat treatment at 430 °C for 1 hour to obtain a glass substrate with a polyimide resin film having a film thickness of 10 μm. For the obtained glass substrate with polyimide film formed by Al sputtering, those without visible bulges or cracks are evaluated as "S", and those with cracks or bulges are evaluated as "B".

[0290] <Evaluation of Reheating Test at 430 °C> Evaluate the glass substrate with polyimide resin film and the device produced by the same method as <Evaluation of Yellowness Index (YI value) and Haze Value>.

[0291] After measuring the YI value (YI(A)) of the glass substrate with polyimide film obtained by heat curing at 430 °C using a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd. and using a D65 light source, adjust it so that the oxygen concentration in the storage reaches 10 mass ppm or less, and perform a heat treatment at 430 °C for 1 hour to obtain a glass substrate with a polyimide resin film having a film thickness of 10 μm.

[0292] For the obtained glass substrate with polyimide film, measure the YI value (YI(B)) again using a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd. and using a D65 light source, and evaluate the change rate relative to the YI value before heating. The YI value (change rate) is calculated using the following formula. Change rate of YI value: ((YI(B) - YI(A)) / YI(A) × 100 (%)) S: The change rate of the YI value is 0% or more and 10% or less (Evaluation of YI value (change rate) "S") A: The change rate of the YI value exceeds 10% and is 20% or less (Evaluation of YI value (change rate) "A") B: The change rate of the YI value exceeds 20% (Evaluation of YI value (change rate) "B")

[0293] <Evaluation of IR Curing Defects> In this evaluation, assuming mass production, evaluate the amount of defects on the surface of the polyimide film when continuously performing IR (infrared) heat curing (curing) treatment on the resin composition. The resin composition of the embodiment and the comparative example was applied to an alkali-free glass substrate (hereinafter, also referred to as "glass substrate" or simply "substrate") of 100 mm in length, 100 mm in width, and 0.5 mm in thickness, in an area 5 mm inside from the end of the glass substrate, so that the film thickness after curing would be 10 μm. The coating was performed using a slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions). The obtained glass substrate with a coating film was subjected to a vacuum dryer (manufactured by Tokyo Ohka Kogyo) to remove the solvent under the conditions of 80°C, 100 Pa, and 30 minutes to obtain a coating film sample.

[0294] After that, 10 samples of the same resin composition were heated at 120°C for 10 minutes in a nitrogen atmosphere using an IR curing furnace AMK-1707 (light source: ceramic heater, furnace volume 50 L, manufactured by AMK), and then heated at 430°C for 60 minutes at a rate of 10°C / min. This was regarded as one batch, and five batches of the same resin composition were used for heat treatment (10 pieces * 5 batches, a total of 50 pieces were treated). In addition, when treating other compositions, the IR curing furnace was fired at 500°C for more than 5 hours, and the pipes such as the conduit were cleaned before use. Next, the fifth polyimide resin film from the upper stage of the fifth batch was used, and the defects on the surface of the polyimide resin film were evaluated using a defect inspection device (LCF-5505XU, manufactured by Takano Co., Ltd.). The number of defects larger than 10 μm was inspected. The evaluation was performed based on the following criteria. The number of defects is less than 25: A (excellent) The number of defects is 25 or more and less than 50: B (excellent) The number of defects is 50 or more and less than 100: C (good) The number of defects is more than 100 and less than 200: D (Pass) The number of defects is more than 200: E (unqualified)

[0295] <Degassing Evaluation> When a polyimide resin film is used as a substrate for a TFT, an inorganic film (e.g., SiN) is formed on the obtained polyimide resin film, and an annealing treatment of the inorganic film is performed. If degassing occurs during the annealing treatment, it will become a defective sample, so the higher the degassing start temperature, the better. The degassing start temperature is evaluated by the following method.

[0296] The resin composition of the embodiment and the comparative example was applied to an alkali-free glass substrate (hereinafter, also referred to as "glass substrate" or simply "substrate") of 100 mm in length, 100 mm in width, and 0.5 mm in thickness, in an area 5 mm inside from the end of the glass substrate, so that the film thickness after curing would be 10 μm. The coating was performed using a slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions). The solvent was removed from the obtained glass substrate with a coating film using a reduced pressure dryer (manufactured by Tokyo Ohka Kogyo) at 80°C, 100 Pa, and 30 minutes to obtain a coating film sample. Thereafter, a set of five coated film samples of the resin composition was heated at 120° C. for 10 minutes in a nitrogen atmosphere using an IR curing furnace AMK-1707 (light source: ceramic heater, furnace volume 50 L, manufactured by AMK), and then heated at 430° C. for 60 minutes at a rate of 10° C. / min to obtain a polyimide resin film formed on a glass substrate.

[0297] A SiN film with a thickness of 100 nm was formed on the obtained polyimide resin film by plasma CVD. The obtained glass substrate on which the SiN / polyimide resin film laminate was formed was subjected to a heat treatment using an IR curing furnace AMK-1707 under the following conditions. a. In a nitrogen atmosphere, heat at 120°C for 10 minutes, then increase the temperature at 10°C / min, and heat at 480°C for 60 minutes b. In a nitrogen atmosphere, heat at 120°C for 10 minutes, then increase the temperature at 10°C / min, and heat at 470°C for 60 minutes c. In a nitrogen atmosphere, heat at 120°C for 10 minutes, then increase the temperature at 10°C / min, and heat at 460°C for 60 minutes d. In a nitrogen atmosphere, heat at 120°C for 10 minutes, then increase the temperature at 10°C / min, and heat at 450°C for 60 minutes e. In a nitrogen atmosphere, heat at 120°C for 10 minutes, then increase the temperature at 10°C / min, and heat at 440°C for 60 minutes In addition, the presence or absence of degassing was evaluated based on the following criteria: Under the above conditions a., SiN film bulges / does not bulge: A (excellent) Under the above condition b., SiN film bulges: B (excellent) Under the above condition c., SiN film bulges: C (good) Under the above condition d., the SiN film bulges: D (pass) Under the above condition e., the SiN film bulges: E (failed)

[0298] [Synthesis Examples 1 and 2] (Synthesis example 1-1-1) After nitrogen substitution in a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube, 20 g of N-methyl-2-pyrrolidone (NMP) and 22.22 mmol of 9,9-bis(4-aminophenyl)fluorene (44BAFL) were added and stirred to dissolve 44BAFL. Then, 20.00 mmol of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride (BPAF), 11.41 g of N-methyl-2-pyrrolidone (NMP) and 21.76 g of toluene were added at 40°C, and polymerization was carried out at 180°C for 4 hours under nitrogen flow. One hour after reaching 180°C, a mixture of water and toluene was extracted from the Dean-Stark tube. The weight average molecular weight (Mw) of the imide after 4 hours of reaction was 19,178, and the number average molecular weight (Mn) was 8,283.

[0299] After 4 hours of reaction, the mixture was cooled until the internal temperature reached 80°C, and 82.82 mmol of 4-aminophenyl-4'-aminobenzoate (APAB) and 100 g of NMP were added, and APAB was completely dissolved while stirring. After visually confirming that APAB was completely dissolved, 86.17 mmol of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added, and the mixture was stirred at 80°C for 1 hour under a nitrogen flow, and at 60°C for 2 hours, and then polymerization was carried out at room temperature overnight. Thereafter, the above-mentioned NMP was added and adjusted so that the solid content became 12% by mass to obtain an NMP solution of a polyimide-polyamide copolymer (hereinafter also referred to as a varnish). The weight average molecular weight (Mw) of the obtained polyamide-amide copolymer was 155,382, and the number average molecular weight (Mn) was 64,063.

[0300] (Synthesis example 1-1-2) (a) Polyimide Synthesis After nitrogen substitution in a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube, 20 g of N-methyl-2-pyrrolidone (NMP) and 22.22 mmol of 9,9-bis(4-aminophenyl)fluorene (44BAFL) were added and stirred to dissolve 44BAFL. Then, 20.00 mmol of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride (BPAF), 11.41 g of N-methyl-2-pyrrolidone (NMP) and 21.76 g of toluene were added at 40°C, and polymerization was carried out at 180°C for 4 hours under nitrogen flow. One hour after reaching 180°C, a mixture of water and toluene was extracted from the Dean-Stark tube. The weight average molecular weight (Mw) of the imide after 4 hours of reaction was 19,804, and the number average molecular weight (Mn) was 8,886. After the reaction was allowed to proceed for 4 hours, the mixture was cooled until the internal temperature reached 80° C., and NMP was added to obtain an NMP solution of polyimide having a concentration of 20% by mass (hereinafter also referred to as polyimide varnish).

[0301] (b) Polyamine Synthesis After nitrogen substitution in a 500 ml four-necked flask, 82.82 mmol of 4-aminophenyl 4'-aminobenzoate (APAB) and 100 g of NMP were added, and APAB was completely dissolved while stirring. After visually confirming that APAB was completely dissolved, 86.17 mmol of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added, and the mixture was stirred at 80°C for 5 hours under a nitrogen flow, and then polymerized overnight at room temperature. Thereafter, the above-mentioned NMP was added and adjusted to a solid content of 20% by mass to obtain an NMP solution of polyamide (hereinafter also referred to as polyamide varnish). The weight average molecular weight (Mw) of the obtained polyamide was 73,044, and the number average molecular weight (Mn) was 34,917.

[0302] (c) Synthesis of polyamide-imide copolymer The polyimide varnish obtained in (a) and the polyamide varnish obtained in (b) are mixed and stirred at room temperature for 24 hours to obtain an NMP solution of a polyamide-imide copolymer.

[0303] (Synthesis Example 1-12) After nitrogen substitution in a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube, 20 g of N-methyl-2-pyrrolidone (NMP) and 22.22 mmol of 9,9-bis(4-aminophenyl)fluorene (44BAFL) were added and stirred to dissolve 44BAFL. Then, 10.00 mmol of 9,9-bis(3,4-dicarboxyphenyl)fluorene anhydride (BPAF), 10.00 mmol of biphenyltetracarboxylic dianhydride, 11.41 g of N-methyl-2-pyrrolidone (NMP) and 21.76 g of toluene were added at 40°C, and polymerization was carried out at 180°C for 4 hours under a nitrogen flow. One hour after reaching 180°C, a mixture of water and toluene was extracted from the Dean-Stark tube. After 4 hours of reaction, the weight average molecular weight (Mw) of the imide was 19,342, and the number average molecular weight (Mn) was 9,242.

[0304] After 4 hours of reaction, the mixture was cooled until the internal temperature reached 80°C, and 82.82 mmol of 4-aminophenyl-4'-aminobenzoate (APAB) and 100 g of NMP were added, and APAB was completely dissolved while stirring. After visually confirming that APAB was completely dissolved, 86.17 mmol of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added, and polymerization reaction was carried out at 80°C for 1 hour under nitrogen flow. Thereafter, the above-mentioned NMP was added and adjusted so that the solid content became 12% by mass, thereby obtaining an NMP solution of a polyimide-polyamide copolymer (hereinafter also referred to as a varnish). The weight average molecular weight (Mw) of the obtained polyamide-amide copolymer was 40,578, and the number average molecular weight (Mn) was 19,128.

[0305] (Synthesis Examples 1-2 to 1-11, and 1-13 to 1-30) In the above-mentioned Synthesis Example 1-1-1, the types and addition amounts of the raw materials were changed as described in Table 1, and a polyamide-imide copolymer varnish was obtained in the same manner as Synthesis Example 1-1-1.

[0306] (Synthesis example 1-1-3) To the NMP solution synthesized in the above-mentioned Synthesis Example 1-1-1, 0.04 mol of 1-methylimidazole was added relative to 1 mol of the repeating unit of the polyimide-polyamide copolymer to obtain a polyamide-imide copolymer varnish.

[0307] (Synthesis example 1-1-4) To the NMP solution synthesized in the above-mentioned Synthesis Example 1-1-1, 0.13 mol of 1-methylimidazole was added relative to 1 mol of the repeating unit of the polyimide-polyamide copolymer to obtain a polyamide-imide copolymer varnish.

[0308] (Synthesis example 1-1-5) To the NMP solution synthesized in the above Synthesis Example 1-1-1, 0.13 mol of N-Boc-imidazole was added relative to 1 mol of the repeating unit of the polyimide-polyamide copolymer to obtain a polyamide-imide copolymer varnish.

[0309] (Synthesis example 1-1-6) To the NMP solution synthesized in the above-mentioned Synthesis Example 1-1-1, 0.04 mol of 1-methylimidazole and 0.04 mol of N-Boc-imidazole were added relative to 1 mol of the repeating unit of the polyimide-polyamide copolymer to obtain a polyamide-imide copolymer varnish.

[0310] (Synthesis example 2-1) After nitrogen substitution in a 500 ml four-necked flask, 49.50 mmol of 4-aminophenyl 4'-aminobenzoate (APAB) and 80 g of NMP were added, and APAB was completely dissolved while stirring. After visually confirming that APAB was completely dissolved, 50.00 mmol of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was added, and the mixture was stirred at 80°C for 5 hours under a nitrogen flow, and then polymerized overnight at room temperature. Thereafter, the above-mentioned NMP was added and adjusted to a solid content of 12% by mass, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as polyamide varnish). The weight average molecular weight (Mw) of the obtained polyamide was 63,353, and the number average molecular weight (Mn) was 29,472.

[0311] (Synthesis example 2-2) After nitrogen substitution in a 500 ml four-necked flask, 4-aminophenyl 4'-aminobenzoate (APAB) 31.68 mmol, 9,9-bis(aminophenyl)fluorene (BAFL) 7.92 mmol, and NMP 70 g were added, and APAB and BAFL were completely dissolved while stirring. After visually confirming that APAB and BAFL were completely dissolved, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) 32.00 mmol, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) 8.00 mmol, and NMP 22.29 g were added, and stirred at 80°C for 5 hours under a nitrogen flow, and then polymerization was carried out at room temperature overnight. Thereafter, the above-mentioned NMP was added and adjusted so that the solid content was 12% by mass, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as polyamide varnish). The weight average molecular weight (Mw) of the obtained polyamine was 72,118, and the number average molecular weight (Mn) was 33,741.

[0312] (Synthesis example 2-3) The polyamide-imide copolymer varnish was synthesized by the same method as Example 1 of International Publication No. 2020 / 138360.

[0313] (Synthesis example 2-4) The polyimide varnish was synthesized by the same method as Example 1 of International Publication No. 2019 / 188305.

[0314] The abbreviations of the components in the following table have the following meanings. BPDA:3,3',4,4'-Biphenyltetracarboxylic dianhydride ODPA:4,4'-Oxydiphthalic Dianhydride BPAF:9,9-bis(3,4-dicarboxyphenyl)fluoranhydride TAHQ: terephthalic anhydride BPF-PA: 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorenic anhydride 6FDA: 4,4'-(Hexafluoroisopropylidene)diphthalic anhydride APAB:4-aminophenyl-4'-aminobenzoate pPD: p-phenylenediamine 44BAFL:9,9-Bis(4-aminophenyl)fluorene 33BAFL:9,9-Bis(3-aminophenyl)fluorene BFAF:9,9-bis(3-fluoro-4-aminophenyl)fluorene 33DAS:3,3'-Diaminodiphenylsulfone 44DAS:4,4'-Diaminodiphenylsulfone 44ODA:4,4'-diaminodiphenyl ether 34ODA:3,4'-diaminodiphenyl ether BAOFL:9,9-Bis[4-(aminophenoxy)phenyl]fluorene BAHF:9,9-Bis[3-amino-4-hydroxyphenyl]fluorene NMP: N-methyl-2-pyrrolidone DMF: N,N-dimethylformamide

[0315] <Implementation Method I> The varnish obtained in each synthesis example was used as a resin composition as it is, and was evaluated according to the above method. The synthesis results are shown in Table 1, and the evaluation results are shown in Tables 2 to 4.

[0316] According to Tables 1 and 2, the polyimide film composed of only structural unit N (polyamide) (Comparative Example 1-1) has excellent residual stress, but has large YI value and Haze value. In addition, the polyimide film obtained from polyamide synthesized with the same composition as the polyamide-imide copolymer (the molar ratio of the monomers constituting X1 to X4 is the same) described in Comparative Example 1-2 has excellent YI value and Haze value, but has large residual stress and does not show performance sufficient for use as a substrate for an optical display.

[0317] Furthermore, the polyimide film (Comparative Example 1-3) obtained from the polyamide-imide copolymer obtained by the method described in Example 1 of the handbook of International Publication No. 2020 / 138360 without using the general formula (A-1) or (A-2) as X2 in the structural unit N was colored yellow in the 430°C heat treatment step, and the YI value and Haze value were large. In addition, the polyimide film (Comparative Example 1-4) composed only of the structural unit M (polyimide) and obtained from the polyimide obtained by the method described in Example 1 of the handbook of International Publication No. 2019 / 188305 was suppressed from yellowing in the 430°C heat treatment step, but on the other hand, the residual stress was high, and the performance was insufficient when used as a substrate for an optical display.

[0318] On the other hand, the polyimide film obtained from the polyamide-imide copolymer containing the structural unit represented by the general formula (1) and the structure represented by the general formula (A-1) or (A-2) as X2 described in Examples 1-1 to 1-30 has a low yellowness (YI value) of 15 or less, and a haze (Haze value) of 0.5% or less, and has sufficient performance to be used as a substrate for an optical display. In addition, the residual stress is also low at 25 MPa or less, and the mechanical properties are also sufficient. Based on the above, it is confirmed that the polyimide resin film obtained from the resin composition of the present invention is a resin film with low yellowness, low haze, and low residual stress.

[0319] Specifically, in the present invention, a resin film having a residual stress of 25 MPa or less, a yellowness of 15 or less, and a haze of 0.5% or less is obtained.

[0320] In addition, a polyamide-imide copolymer varnish can be obtained by separately synthesizing polyamide and polyimide as in Synthesis Example 1-1-2, and then mixing them to react. The polyimide film obtained from the varnish has the same performance as that of Example 1-1-1 as shown in Example 1-1-2. This means that by mixing (a) polyamide and (b) polyimide synthesized at a specific molar ratio to react, (c) polyamide-imide copolymer can be obtained.

[0321] In Table 2, in Example 1-8 in which the molar ratio of the structural unit N of the polyamide containing X1 and X2 to the structural unit M of the polyimide containing X3 and X4 (the molar number of the structural unit N: the molar number of the structural unit M) is 60:40, a transparent film with excellent yellowness and haze can be obtained, the residual stress is also low at less than 25 MPa, and the mechanical properties are also sufficient.

[0322] In addition, as shown in Table 2, when the ratio of X4 / X3 is 1.01 to 2 and the ratio of diamine to acid dianhydride is increased, the ratio of the terminal of polyimide to amine is increased, so when reacting with polyamic acid, the reactivity of polyamic acid and polyimide is increased, and when forming a film, polyimide is well dispersed, so a transparent film with excellent yellowness (YI value) and haze (Haze value) can be obtained. In addition, according to Examples 1-6, 1-14, and 1-15, the yellowness (YI value) of the composition with a ratio of X4 / X3 of 1.11 is low and particularly preferred.

[0323] In addition, as shown in Table 3 in Examples 2-2 to 2-5, the film obtained from the polyimide-polyamide copolymer containing 1-methylimidazole or N-Boc-imidazole as the imidization catalyst has a lower yellowness (YI value) and can be preferably used as a substrate for a display.

[0324] Furthermore, as shown in Comparative Example 2-1 (Synthesis Example 2-1) in Table 4, the polyimide film obtained from polyamide acid composed only of structural unit N has a high elastic modulus at 25°C and 350°C, and does not bulge or crack even when heated to 430°C after Al sputtering. However, the YI value is high, and its performance as a substrate for optical displays is insufficient.

[0325] In Table 4, as shown in Comparative Example 2-2 (Synthesis Example 2-2), when the elastic modulus is low at 350°C, bulging or cracking occurs when the Al is sputtered and then heated to 430°C. This is considered to be because the elastic modulus is low at high temperatures due to the high content of the polyimide part, so the difference in contraction force between Al and polyimide increases in the high temperature range of 350°C or more, resulting in cracking or bulging.

[0326] On the other hand, when the elastic modulus at 350°C is 0.5 GPa or more, even if the difference in shrinkage force increases in the high temperature region, the strength of the film is relatively high, so no cracks or bulges occur, and it can be preferably used as a substrate for a display. Furthermore, as shown in Examples 3-1 to 3-3 in Table 4, the film with a relatively high elastic modulus at 350°C and a haze value of 0.5% or less without phase separation has a relatively small change rate of the YI value in the 430°C reheating test, and can be preferably used as a substrate for a display.

[0327] Specifically, in the present invention, a resin film having an elastic modulus of 6 GPa or more at 25° C., an elastic modulus of 0.5 GPa or more at 350° C., and a haze of 0.5% or less can be obtained.

[0328] [Table 1] Table 1 serial number Polyamine Polyimide Department Imidyl content Morelby Tetracarboxylic dianhydride (A-1) [Molar %] Diamine (B-1) [Molar %] Tetracarboxylic dianhydride (A-2) [Molar %] Diamine (B-2) [Molar %] BPDA ODPA TAHQ APAB pD 44BAFL BPAF BPDA ODPA BPF-PA 6FDA APAB 44BAFL 33BAFL BFAF 33DAS 44DAS 44ODA 34ODA BAOFL BAHF mol% [B-2] / [A-2] [B-1] / [A-1] ([Bl]+[B-2]) / ([A-1A-2]) Synthesis example 1 1-1 100 100 100 100 20 1.11 0.96 0.988 1-2 100 100 100 100 20 1.11 0.96 0.988 1-3 100 100 100 100 20 1.11 0.96 0.988 1-4 100 100 100 100 20 1.11 0.96 0.988 1-5 100 100 100 100 20 1.11 0.96 0.988 2 100 100 100 100 20 1.11 0.96 0.99 3 100 100 100 100 20 1.11 0.96 0.988 4 100 100 100 100 20 1.11 0.969 0.996 5 100 100 100 100 30 1.11 0.95 0.996 6 100 100 100 100 5 1.01 0.99 0.996 7 100 100 100 100 40 1.11 0.92 0.992 8 100 100 100 100 20 1.11 0.969 0.996 9 100 100 100 100 20 1.11 0.969 0.996 10 100 100 100 100 20 1.11 0.969 0.996 11 100 100 100 100 20 1.11 0.96 0.988 12 100 100 50 50 100 20 1.11 0.96 0.988 13 100 100 50 50 100 20 1.11 0.96 0.988 14 100 100 50 50 100 20 1.25 0.94 0.991 15 100 100 50 50 100 20 2 0.84 0.99 16 100 100 100 50 50 20 1.11 0.969 0.996 17 100 100 100 50 50 20 1.11 0.96 0.988 18 100 100 100 50 50 30 1.11 0.96 0.988 19 100 100 50 50 100 20 1.11 0.96 0.988 20 100 100 100 50 50 20 1.11 0.969 0.996 21 100 100 50 50 100 20 1.11 0.96 0.988 22 100 100 50 50 100 20 1.11 0.96 0.988 23 100 100 75 25 100 20 1.11 0.969 0.996 24 80 20 100 100 100 20 1.11 0.96 0.988 25 100 100 100 100 20 1.11 0.96 0.988 26 100 80 20 100 100 20 1.11 0.96 0.988 27 100 80 20 100 100 20 1.11 0.96 0.988 28 50 50 100 100 100 20 1.11 0.96 0.988 29 100 100 100 100 20 1.11 0.969 0.996 30 100 100 100 65 35 20 1.11 0.969 0.996

[0329] [Table 2] Table 2 Synthesis example Yellowness (YI value) Haze (Haze value) Residual stress Example 1 1-1 1-1-1 A S A 1-2 1-1-2 A S A 1-3 1-1-3 S S A 1-4 1-1-4 S S A 1-5 1-1-5 S S A 1-6 1-1-6 S S A 2 1-2 A S A 3 1-3 A S A 4 1-4 S S S 5 1-5 S S A 6 1-6 A S S 7 1-7 S S A 8 1-8 A S A 9 1-9 A S S 10 1-10 A S S 11 1-11 A S A 12 1-12 S S A 13 1-13 S S A 14 1-14 A S A 15 1-15 A S A 16 1-16 A S A 17 1-17 S A A 18 1-18 S A A 19 1-19 A S A 20 1-20 A S A 21 1-21 S S A 22 1-22 A A S 23 1-23 A S A 24 1-24 A S A 25 1-25 A A A 26 1-26 A A S 27 1-27 A S A 28 1-28 A S A 29 1-29 A S A 30 1-30 A S A Comparative Example 1 1 2-1 B B A 2 2-2 A A B 3 2-3 B B A 4 2-4 A A B

[0330] [Table 3] Table 3 Synthesis example Storage stability Example 2 1 1-1 A 2 1-3 A 3 1-4 A 4 1-5 A 5 1-6 A

[0331] [Table 4] Table 4 Synthesis example YI value 25℃ Modulus of elasticity 350℃ Modulus of elasticity Sputtering Reheating test 430℃ reheating test Example 3 1 1-4 S S S S S 2 1-12 S S S S S 3 1-13 S S S S S Comparative Example 2 1 2-1 B S S S S 2 2-2 S B B B B

[0332] <Implementation Method IV>

[0333] (Synthesis Example 1-31) The same method as Synthesis Example 1-1-1 was followed except that the amount of APAB in Synthesis Example 1-1-1 was changed to 83.02 mmol. The weight average molecular weight (Mw) of the obtained polyamide-imide copolymer was 173,000.

[0334] (Synthesis example 1-32) The same method as in Synthesis Example 1-1-1 was used except that BAFL in Synthesis Example 1-1-1 was changed to 33DAS and the amount of APAB was changed to 83.02 mmol. The weight average molecular weight (Mw) of the obtained polyamide-imide copolymer was 171,000.

[0335] (Synthesis Example 1-33) The same method as Synthesis Example 1-1-1 was used except that the amount of APAB in Synthesis Example 1-1-1 was changed to 83.45 mmol. The weight average molecular weight (Mw) of the obtained polyamide-imide copolymer was 224,000.

[0336] (Synthesis example 1-34) The same method as Synthesis Example 1-1-1 was used except that BAFL in Synthesis Example 1-1-1 was changed to 33DAS and the amount of APAB was changed to 83.45 mmol. The weight average molecular weight (Mw) of the obtained polyamide-imide copolymer was 221,000.

[0337] (Synthesis example 3-1) In a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) from an 18 L can just after opening was added to a solid content of 25 wt%, and 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 180.77 g (800 mmol) was added, and APAB was dissolved by stirring. Then, biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) 235.38 g (792 mmol) was added, and a polymerization reaction was carried out at 70°C and stirred for 5 hours under a nitrogen flow. Then, the mixture was cooled to room temperature and left to stand for 8 days under a nitrogen flow. The NMP was added and adjusted to a solution viscosity of 10,000 mPa·s to obtain a polyamine NMP solution (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamine was 152,000.

[0338] (Synthesis example 3-2) In a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) from an 18 L can just after opening was added to a solid content of 25 wt%, and 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 181.69 g (800 mmol) was added, and APAB was dissolved by stirring. Then, biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) 235.38 g (792 mmol) was added, and a polymerization reaction was carried out at 70°C and stirred for 5 hours under a nitrogen flow. Then, the mixture was cooled to room temperature and left to stand for 8 days under a nitrogen flow. The NMP was added and adjusted to a solution viscosity of 10,000 mPa·s to obtain a polyamine NMP solution (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamine was 175,000.

[0339] (Synthesis example 3-3) Into a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) immediately after opening an 18 L can was added to a solid content of 25 wt%, 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 145.35 g (800 mmol) and 4,4'-diaminodiphenylsulfone (4,4'-DAS, purity 99.5%, manufactured by Seika Co., Ltd.) 39.53 g (159 mmol) were added, and APAB and 4,4'-DAS were dissolved by stirring. Subsequently, 235.38 g (800 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) was added, and a polymerization reaction was carried out at 70°C for 5 hours under a nitrogen flow and stirring. Then, the mixture was cooled to room temperature and allowed to stand for 8 days under a nitrogen stream. The above-mentioned NMP was added and adjusted so that the solution viscosity became 10,000 mPa·s, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamide was 173,000.

[0340] (Synthesis Example 3-4) In a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) from an 18 L can just after opening was added to a solid content of 25 wt%, and 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 181.69 g (800 mmol) was added, and APAB was dissolved by stirring. Then, 235.38 g (796 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) was added, and a polymerization reaction was carried out at 70°C and stirred for 5 hours under a nitrogen flow. Then, the mixture was cooled to room temperature and left to stand for 8 days under a nitrogen flow. The NMP was added and adjusted so that the solution viscosity became 10,000 mPa·s, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamide was 242,000.

[0341] (Synthesis Example 3-5) In a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) from an 18 L can just after opening was added to a solid content of 25 wt%, and 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 182.42 g (800 mmol) was added, and APAB was dissolved by stirring. Then, biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) 235.38 g (799 mmol) was added, and a polymerization reaction was carried out at 70°C and stirred for 5 hours under a nitrogen flow. Then, the mixture was cooled to room temperature and left to stand for 8 days under a nitrogen flow. The NMP was added and adjusted so that the solution viscosity became 10,000 mPa·s, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamide was 241,000.

[0342] (Synthesis Example 3-6) In a 5 L separable flask purged with nitrogen, an amount of N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) from an 18 L can just after opening was added to a solid content of 25 wt%, and 4-aminophenyl 4-aminobenzoate (APAB, purity 99.5%, manufactured by Japan Junryo Pharmaceutical Co., Ltd.) 80 mmol was added, and APAB was dissolved by stirring. Then, bis(1,3-dioxa-1,3-dihydroisobenzofuran-5-carboxylic acid) 2,2',3,3',5,5'-hexamethylbiphenyl-4,4'-diyl (manufactured by Honshu Chemical Industry Co., Ltd.) 79.6 mmol was added, and a polymerization reaction was carried out at 70°C and stirred for 5 hours under a nitrogen flow. Then, the mixture was cooled to room temperature and left to stand for 8 days under a nitrogen flow. The NMP was added and adjusted so that the solution viscosity became 10,000 mPa·s, thereby obtaining an NMP solution of polyamide (hereinafter also referred to as varnish). The weight average molecular weight (Mw) of the obtained polyamide was 172,000.

[0343] (Reference Example 4-1) The above-mentioned IR curing defect evaluation and degassing evaluation were performed using the NMP solution of the polyimide-polyamic acid copolymer (hereinafter also referred to as PAI) synthesized in Synthesis Example 1-1-1. The results are recorded in Table 6.

[0344] (Example 4-1) Using the NMP solution of the polyimide-polyamic acid copolymer synthesized in Synthesis Example 1-32, 1 part by mass of the imidization catalyst 1 (1-methylimidazole) described in Table 6 was added relative to 100 parts by mass of the polyimide-polyamic acid copolymer, and stirred at room temperature for 24 hours to obtain a polyamic acid-imide copolymer varnish. The varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are recorded in Table 6.

[0345] (Examples 4-2 to 30) The NMP solution of the polyimide-polyamic acid copolymer described in Table 6 was used, and the imidization catalyst described in Table 5 was added in the amount described in Table 6. The polyamic acid-imide copolymer varnish was obtained in the same manner as in Example 4-1. The obtained varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are recorded in Table 6.

[0346] (Example 4-31) Using the NMP solution of the polyimide-polyamic acid copolymer described in Table 6, the imidization catalyst described in Table 5 was added in the amount described in Table 6, and 20 parts by mass of cyclobutane sulfonate, which is an aprotic polar substance with a boiling point of 250-350°C, was added relative to 100 parts by mass of NMP. A polyamic acid-imide copolymer varnish was obtained in the same manner as in Example 4-1. The obtained varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are recorded in Table 6.

[0347] (Comparative Example 5-1) The above-mentioned IR curing defect evaluation and degassing evaluation were performed using the NMP solution of polyamine (hereinafter also referred to as PAA) synthesized in Synthesis Example 3-1. The results are recorded in Table 7.

[0348] (Example 5-1) The NMP solution of the polyamide synthesized in Synthesis Example 3-2 was used, and 1 part by mass of the imidization catalyst 1 (1-methylimidazole) described in Table 5 was added relative to 100 parts by mass of the polyamide copolymer, and stirred at room temperature for 24 hours to obtain a polyamide varnish. The varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are recorded in Table 7.

[0349] (Examples 5-2 to 29, Comparative Example 5-2) A polyamide varnish was obtained in the same manner as in Example 5-1 except that the NMP solution of polyamide described in Table 7 was used and the imidization catalyst described in Table 5 was added in the amount described in Table 7. The obtained varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are described in Table 7.

[0350] (Example 5-30) The polyamide varnish was obtained in the same manner as in Example 5-1 except that the NMP solution of polyamide described in Table 7 was used, the imidization catalyst described in Table 5 was added in the amount described in Table 7, and 20 parts by mass of cyclobutane sulfonate, which is an aprotic polar substance with a boiling point of 250-350°C, was added relative to 100 parts by mass of NMP. The obtained varnish was used to perform the above-mentioned IR curing defect evaluation and degassing evaluation. The results are described in Table 7.

[0351] [Table 5] Table 5 Imidization catalyst Compound Name 1 1-Methylimidazole 2 N-BOC Imidazole 3 2-Methylimidazole 4 2-Phenylimidazole 5 Benzimidazole 6 2-Ethyl-4-methylimidazole 7 4-Ethyl-2-methylimidazole 8 4-Methyl-2-phenylimidazole 9 2-Undecyl imidazole 10 1-Benzyl-2-methylimidazole 11 1-Benzyl-2-phenylimidazole 12 1H-Imidazole 13 1,2-Dimethylimidazole 14 4-Dimethylaminopyridine 15 2,2'-Bipyridine 16 Nicotinic acid-pyridine carboxylic acid 17 Isoquinoline 18 Pyridine 19 2-Methylpyridine 20 1,8-Diazabicyclo[5.4.0]-7-undecene twenty one 1,4-Diazabicyclo[2.2.2]octane twenty two N-Methylmorpholine twenty three Triethylamine

[0352] [Table 6] Table 6 Reference example / Example / Comparative example Resin Weight average molecular weight [Mw] Imidization catalyst bp250- 350 oC aprotic polar substances Evaluation Project Synthesis example Polymer structure type Addition amount (parts by mass) IR curing defect evaluation Degassing evaluation Reference Example 4 1 1-1-1 PAI 155,382 none - - E E Example 4 1 1-31 PAI 173,000 none - - D D Example 4 2 1-31 PAI 173,000 1 1 - B C Example 4 3 1-32 PAI 171,000 2 1 - B C Example 4 4 1-32 PAI 171,000 1 5 - B B Example 4 5 1-31 PAI 173,000 2 5 - B B Example 4 6 1-31 PAI 173,000 1 10 - B B Example 4 7 1-32 PAI 171,000 2 10 - B B Example 4 8 1-31 PAI 173,000 3 10 - C C Example 4 9 1-32 PAI 171,000 4 10 - C C Example 4 10 1-31 PAI 173,000 5 10 - C C Example 4 11 1-32 PAI 171,000 6 10 - C C Example 4 12 1-31 PAI 173,000 7 10 - C C Example 4 13 1-32 PAI 171,000 8 10 - C C Example 4 14 1-31 PAI 173,000 9 10 - C C Example 4 15 1-32 PAI 171,000 10 10 - C C Example 4 16 1-31 PAI 173,000 11 10 - C C Example 4 17 1-31 PAI 173,000 12 10 - D C Example 4 18 1-32 PAI 171,000 13 10 - D C Example 4 19 1-31 PAI 173,000 14 10 - C C Example 4 20 1-32 PAI 171,000 15 10 - C C Example 4 twenty one 1-31 PAI 173,000 16 10 - C C Example 4 twenty two 1-32 PAI 171,000 17 10 - C C Example 4 twenty three 1-31 PAI 173,000 18 10 - D C Example 4 twenty four 1-31 PAI 173,000 19 10 - C C Example 4 25 1-32 PAI 171,000 20 10 - C C Example 4 26 1-31 PAI 173,000 twenty one 10 - C C Example 4 27 1-32 PAI 171,000 twenty two 10 - C C Example 4 28 1-32 PAI 171,000 twenty three 10 - D C Example 4 29 1-33 PAI 224,000 1 10 - A B Example 4 30 1-34 PAI 221,000 2 10 - A B Example 4 31 1-33 PAI 224,000 2 10 Cyclobutane A A

[0353] [Table 7] Table 7 Examples / Comparative Examples Resin Weight average molecular weight [Mw] Imidization catalyst bp250-350℃ non-protonic polar substances Evaluation Project Synthesis example Polymer structure type Addition amount (parts by mass) IR curing defect evaluation Degassing evaluation Comparative Example 5 1 3-1 PAA 152,000 none - - E E Example 5 1 3-2 PAA 175,000 1 1 - C C Example 5 2 3-3 PAA 173,000 2 1 - C C Example 5 3 3-2 PAA 175,000 1 5 - C B Example 5 4 3-3 PAA 173,000 2 5 - C B Example 5 5 3-2 PAA 175,000 1 10 - B B Example 5 6 3-3 PAA 173,000 2 10 - B B Example 5 7 3-2 PAA 175,000 3 10 - D D Example 5 8 3-3 PAA 173,000 4 10 - D D Example 5 9 3-2 PAA 175,000 5 10 - D D Example 5 10 3-3 PAA 173,000 6 10 - D D Example 5 11 3-2 PAA 175,000 7 10 - D D Example 5 12 3-3 PAA 173,000 8 10 - D D Example 5 13 3-2 PAA 175,000 9 10 - D D Example 5 14 3-3 PAA 173,000 10 10 - D D Example 5 15 3-2 PAA 175,000 11 10 - D D Example 5 16 3-3 PAA 173,000 12 10 - D D Comparative Example 5 2 3-2 PAA 175,000 13 10 - E E Example 5 17 3-3 PAA 173,000 14 10 - D D Example 5 18 3-2 PAA 175,000 15 10 - D D Example 5 19 3-3 PAA 173,000 16 10 - D D Example 5 20 3-2 PAA 175,000 17 10 - D D Example 5 twenty one 3-3 PAA 173,000 18 10 - D D Example 5 twenty two 3-2 PAA 175,000 19 10 - D D Example 5 twenty three 3-3 PAA 173,000 20 10 - D D Example 5 twenty four 3-2 PAA 175,000 twenty one 10 - D D Example 5 25 3-3 PAA 173,000 twenty two 10 - D D Example 5 26 3-2 PAA 175,000 twenty three 10 - D D Example 5 27 3-6 PAA 172,000 1 10 - B B Example 5 28 3-5 PAA 241,000 2 10 - A B Example 5 29 3-4 PAA 242,000 1 10 - A B Example 5 30 3-5 PAA 241,000 2 10 Cyclobutane A A

[0354] <Implementation Method II> The varnish obtained in each synthesis example was used as a resin composition as it is, and was evaluated according to the above method. The synthesis results are shown in Table 8, and the evaluation results are shown in Tables 9 and 10.

[0355] According to Tables 8 and 9, the polyimide film composed only of structural unit N (polyamide) (Comparative Example II-1-1) has excellent residual stress, but has large YI value and Haze value. In addition, the polyimide film obtained from polyamide synthesized with the same composition as the polyamide-imide copolymer (the molar ratio of monomers constituting X1 to X4 is the same) described in Example II-1-1 has excellent YI value and Haze value, but has increased residual stress, and neither shows performance sufficient for use as a substrate for an optical display.

[0356] Furthermore, the polyimide film (Comparative Example II-1-3) obtained from the polyamide-imide copolymer obtained by the method described in Example 1 described in the handbook of International Publication No. 2020 / 138360 without using the general formula (A-1) or (A-2) as X2 in the structural unit N was colored yellow in the 430°C heat treatment step, and the YI value and Haze value were large. In addition, the polyimide film (Comparative Example II-1-4) composed only of the structural unit M (polyimide) and obtained from the polyimide obtained by the method described in Example 1 described in the handbook of International Publication No. 2019 / 188305 was suppressed from yellowing in the 430°C heat treatment step, but on the other hand, the residual stress was high, and the performance as a substrate for an optical display was insufficient.

[0357] On the other hand, as in Example II-1-1-1, the polyimide film obtained from the polyamide-imide copolymer containing at least one selected from the group consisting of the structure represented by the general formula (A-1), the structure derived from 4,4'-oxydiphthalic anhydride (ODPA), and the structure derived from 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) as X3 has a low yellowness (YI value) of 15 or less, and a haze (Haze value) of 0.5% or less, and has sufficient performance to be used as a substrate for an optical display. In addition, the residual stress is also low at 25 MPa or less, and the bending resistance is excellent, and the mechanical properties are sufficient. Based on the above, it is confirmed that the polyimide resin film obtained from the resin composition of the present invention is a resin film with low yellowness, low haze, and low residual stress.

[0358] Specifically, in the present invention, a resin film having a residual stress of 25 MPa or less, a yellowness of 15 or less, a haze of 0.5% or less, and excellent bending resistance can be obtained.

[0359] In addition, a polyamide-imide copolymer varnish can be obtained by separately synthesizing polyamide and polyimide as in Synthesis Example 1-1-2, and then mixing them to react. The polyimide film obtained from the varnish has the same performance as that of Example II-1-1-1, as shown in Example II-1-1-2. This means that by mixing (b) polyamide and (a) polyimide synthesized at a specific molar ratio to react, (c) polyamide-imide copolymer can be obtained.

[0360] On the other hand, as shown in Comparative Example II-1-1 in Table 9, the polyimide film obtained from the polyamide containing only the structural unit N has excellent residual stress, but on the other hand, the bending resistance is insufficient. It is considered that this is because the polyimide film composed of only the structural unit N is very rigid, so in-plane crystallization occurs during the bending test and damage occurs. Therefore, the polyimide copolymer film obtained from the polyamide-imide copolymer containing the structural unit N and the structural unit M has excellent yellowness and haze, low residual stress, and excellent bending resistance.

[0361] Furthermore, as shown in Examples II-1-6, II-1-12, and II-1-13, if the ratio of X4 / X3 is 1.01 to 2 and the ratio of diamine to acid dianhydride is increased, the ratio of the terminal of the polyimide to amine is increased, so when reacting with polyamic acid, the reactivity of polyamic acid and polyimide is increased, and when forming a film, the polyimide is well dispersed, so that a film with excellent yellowness (YI value) and haze (Haze value), excellent bending resistance and transparency is obtained. In addition, according to Examples II-1-6, II-1-12, and II-1-13, the composition with a ratio of X4 / X3 of 1.11 has a low yellowness (YI value) and is particularly preferred.

[0362] In addition, as shown in Examples II-2-1 to II-2-5 in Table 10, the film obtained from the polyimide-polyamide copolymer containing 1-methylimidazole or N-Boc-imidazole as the imidization catalyst has a lower yellowness (YI value) and can be preferably used as a substrate for a display.

[0363] [Table 8] Table 8 serial number Polyamine Polyimide Department Imidyl content Morelby Tetracarboxylic dianhydride (A-1) [Molar %] Diamine (B-1) [Molar %] Tetracarboxylic dianhydride (A-2) [mol %] Diamine (B-2) [Molar %] Synthesis example 1 BPDA ODPA TAHQ APAB pD 44BAFL BPAF BPDA ODPA BPF-PA 6FDA APAB 44BAFL 33BAFL BFAF 33DAS 44DAS 44ODA 34ODA BAOFL BAHF mol% [B-2] / [A-2] [B-1] / [A-1] ([B-l]+[B-2]) / ([A-l]+[A-2]) 1-1 100 100 100 100 20 1.11 0.96 0.988 1-2 100 100 100 100 20 1.11 0.96 0.988 1-3 100 100 100 100 20 1.11 0.96 0.988 1-4 100 100 100 100 20 1.11 0.96 0.988 1-5 100 100 100 100 20 1.11 0.96 0.988 2 100 100 100 100 20 1.11 0.96 0.99 3 100 100 100 100 20 1.11 0.96 0.988 4 100 100 100 100 20 1.11 0.969 0.996 5 100 100 100 100 30 1.11 0.95 0.996 6 100 100 100 100 5 1.01 0.99 0.996 7 100 100 100 100 40 1.11 0.92 0.992 8 100 100 100 100 20 1.11 0.969 0.996 9 100 100 100 100 20 1.11 0.969 0.996 10 100 100 100 100 20 1.11 0.969 0.996 11 100 100 100 100 20 1.11 0.96 0.988 12 100 100 50 50 100 20 1.11 0.96 0.988 13 100 100 50 50 100 20 1.11 0.96 0.988 14 100 100 50 50 100 20 1.25 0.94 0.991 15 100 100 50 50 100 20 2 0.84 0.99 16 100 100 100 50 50 20 1.11 0.969 0.996 17 100 100 100 50 50 20 1.11 0.96 0.988 18 100 100 100 50 50 30 1.11 0.96 0.988 19 100 100 50 50 100 20 1.11 0.96 0.988 20 100 100 100 50 50 20 1.11 0.969 0.996 21 100 100 50 50 100 20 1.11 0.96 0.988 22 100 100 50 50 100 20 1.11 0.96 0.988 23 100 100 75 25 100 20 1.11 0.969 0.996 24 80 20 100 100 100 20 1.11 0.96 0.988 25 100 100 100 100 20 1.11 0.96 0.988 26 100 80 20 100 100 20 1.11 0.96 0.988 27 100 80 20 100 100 20 1.11 0.96 0.988 28 50 50 100 100 100 20 1.11 0.96 0.988 29 100 100 100 100 20 1.11 0.969 0.996 30 100 100 100 65 35 20 1.11 0.969 0.996

[0364] [Table 9] Table 9 Synthesis example Yellowness (YI value) Haze (Haze value) Residual stress Bending resistance Example II-1 1-1 1-1-1 A S A A 1-2 1-1-2 A S A A 1-3 1-1-3 S S A A 1-4 1-1-4 S S A A 1-5 1-1-5 S S A A 1-6 1-1-6 S S A A 2 1-2 A S A A 3 1-3 A S A A 4 1-4 S S S A 5 1-5 S S A A 6 1-6 A S S A 7 1-7 S S A A 8 1-8 A S A A 9 1-9 A S A A 10 1-10 A S S A 11 1-11 A S A A 12 1-12 S S A A 13 1-13 S S A A 14 1-14 A S A A 15 1-15 A S A A 16 1-16 A S A A 17 1-17 S A A A 18 1-18 S A A A 19 1-19 A S A A 20 1-20 A S A A 21 1-21 S S A A 22 1-22 A A S A 23 1-23 A S A A 24 1 - 24 A S A A 25 1 - 25 A A A A 26 1 - 26 A A S A 27 1 - 27 A S A A 28 1 - 28 A S A A 29 1 - 29 A S A A 30 1 - 30 A S A A Comparative Example II - 1 1 2 - 1 B B A B 2 2 - 2 A A B A 3 2 - 3 B B A B 4 2-4 A A B B

[0365] [Table 10] Table 10 Synthesis example Storage stability Example II-2 1 1-1-1 A 2 1-1-3 A 3 1-1-4 A 4 1-1-5 A 5 1-1-6 A

[0366] <Implementation Method III> [Example III-1] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) in an amount corresponding to 15 wt% of the solid content of a freshly opened 18 L can was added as a solvent to the separable flask. 15.69 g (49.0 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was added, and the mixture was stirred to dissolve TFMB. Then, 9.27 g (42.5 mmol) of pyromellitic dianhydride (PMDA) and 3.33 g (7.5 mmol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) were added, and the mixture was stirred at 80°C for 4 hours under a nitrogen flow. After cooling to room temperature, cyclobutane sulfonate, which is a non-protonic polar substance with a boiling point of 250°C to 350°C, was added in a manner such that (mass of the solvent + mass of cyclobutane sulfonate) was 100 wt% to become 3 wt%, and the mixture was further stirred for 1 hour to obtain a polyamide solution (hereinafter also referred to as varnish).

[0367] The varnish was spin-coated on a 6-inch silicon wafer and a 10 cm square EAGLE glass using a MIKASA coater, pre-baked on a hot plate at 100°C for 6 minutes, and then placed in a furnace and heated and cured at 380°C for 1 hour under a nitrogen flow to obtain a polyimide resin film. The film thickness of 39 locations in the plane of the polyimide resin film formed on the silicon wafer was measured using Lambda ACE, and the value obtained by dividing [(the film thickness most deviating from the average value) - (the average film thickness)] by the average film thickness (hereinafter also referred to as the in-plane film thickness uniformity) was 6.0%.

[0368] The YI of the polyimide resin film formed on the EAGLE glass was measured using a fog meter and the result was 7.9 based on a film thickness of 10 μm. Furthermore, the polyimide resin film formed on the EAGLE glass was heated to 400°C and the generated gas components were analyzed by GCMS. As a result, no cyclobutane was detected.

[0369] [Example III-2] In Example III-1, the amount of cyclobutane sulfonate added was changed from 3 wt% to 20 wt%, and a polyamide solution was obtained in the same manner as in Example III-1. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.0%, 7.3, and 0 ppm, respectively.

[0370] [Example III-3] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) was added as a solvent in an amount corresponding to 15 wt% of the solid content of the 18 L can just opened. 15.69 g (49.0 mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was added and stirred to dissolve TFMB. Then, 9.27 g (42.5 mmol) of pyromellitic dianhydride (PMDA) and 3.33 g (7.5 mmol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) were added, and stirred at 80°C for 4 hours under a nitrogen flow. The mixture was cooled to room temperature, and the solution was added dropwise to 6 times the amount of water while stirring to precipitate a polymer. The polymer was separated by filtration and then vacuum dried at 40°C for 24 hours using a vacuum dryer. Then, the polymer was dissolved in cyclobutane sulfonate in a concentration of 15 wt% to obtain a polyamide solution. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.0%, 7.3, and 600 ppm, respectively.

[0371] [Comparative Example III-1] In Example III-1, cyclobutane sulfonate was not added, and a polyamide solution was obtained in the same manner as in Example III-1. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.0%, 8.1, and 0 ppm, respectively.

[0372] [Example III-4] In Example III-2, except that cyclobutane sulfonate was replaced with 3-methylcyclobutane sulfonate, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.0%, 7.6, and 0 ppm, respectively.

[0373] [Example III-5] In Example III-2, except that cyclobutane was replaced with benzophenone, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 4.2%, 7.4, and 0 ppm, respectively.

[0374] [Example III-6] In Example III-2, except that cyclobutane sulfonate was replaced with 2-phenoxyethyl acetate, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 3.3%, 7.6, and 0 ppm, respectively.

[0375] [Example III-7] In Example III-2, except that cyclobutane sulfonate was replaced with diphenyl carbonate, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 3.0%, 7.5, and 0 ppm, respectively.

[0376] [Example III-8] In Example III-2, except that cyclobutane sulfonate was replaced with hexamethylenediamine, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 4.1%, 7.6, and 0 ppm, respectively.

[0377] [Example III-9] In Example III-2, except that cyclobutane sulfonate was replaced with adiponitrile, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 4.0%, 7.5, and 0 ppm, respectively.

[0378] [Example III-10] In Example III-2, except that cyclobutane sulfone was replaced with dibutyl sulfone, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 3.0%, 7.6, and 0 ppm, respectively.

[0379] [Comparative Example III-2] In Example III-2, except that cyclobutane sulfonate was replaced with dimethyl sulfonate, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured to be 12.0%, 8.1, and 0 ppm, respectively.

[0380] [Comparative Example III-3] In Example III-2, except that cyclobutane sulfonate was replaced with diphenyl sulfonate, a polyamide solution was obtained in the same manner as in Example III-2. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 4.0%, 7.5, and 1500 ppm, respectively.

[0381] [Example III-11] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) in an amount corresponding to 20 wt% of the solid content of a freshly opened 18 L can was added as a solvent to the separable flask. 4-aminophenyl 4-aminobenzoate (APAB) 8.95 g (39.2 mmol) and 4,4'-diaminophenyl sulfone (4,4'-DAS) 2.43 g (9.8 mmol) were added and stirred to dissolve the two. Thereafter, 14.71 g (50 mmol) of 4,4'-diphthalic dianhydride (BPDA) was added, and the mixture was stirred at 80°C for 4 hours under a nitrogen stream. The mixture was cooled to room temperature, and cyclobutanesulfonate was added so that (mass of the solvent + mass of cyclobutanesulfonate) was 100 wt% to give 20 wt%, and the mixture was further stirred for 1 hour to obtain a polyamide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.2%, 12.6, and 0 ppm, respectively.

[0382] [Comparative Example III-4] In Example 11, cyclobutane sulfonate was not added, and a polyamide solution was obtained in the same manner as in Example III-11. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 11.0%, 13.5, and 0 ppm, respectively.

[0383] [Example III-12] A 500 ml separable flask was purged with nitrogen, and 22.2 g of N-methylpyrrolidone (NMP: water content 250 ppm) which was just opened from an 18 L can was added to the separable flask as a solvent. 2.61 g (10.53 mmol) of 3,3'-diaminophenylsulfone (3,3'-DAS) was added and stirred to dissolve, and then 2.94 g (9.47 mmol) of 4,4'-oxydiphthalic dianhydride (ODPA) and 20 g of toluene were added. A reflux tube and a Dean-Stark tube were installed in the flask, and the generated water was extracted from the Dean-Stark tube at 180°C under a nitrogen flow. The reaction was carried out for 2 hours under a nitrogen flow, and then the mixture was heated at 180°C for 1 hour, and all the added toluene was extracted from the Dean-Stark tube. Thereafter, the reaction solution was cooled to room temperature, and 81.96 g of N-methylpyrrolidone (NMP: water content 250 ppm) in an 18 L can just after opening, 11.77 g (40 mmol) of 4,4'-diphthalic anhydride (BPDA), and 8.72 g (38.2 mmol) of 4-aminophenyl 4-aminobenzoate (APAB) were added as solvents, and stirred to dissolve. Thereafter, the reaction was carried out at 80°C for 4 hours under a nitrogen flow, and after cooling to room temperature, cyclobutane sulfonate was added to 20 wt% relative to (mass of solvent + mass of cyclobutane sulfonate) 100 wt%, and stirred for 1 hour to obtain a polyamide-soluble polyimide solution (hereinafter, also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.3%, 12.9, and 0 ppm, respectively.

[0384] [Comparative Example III-5] A polyamide-soluble polyimide solution was obtained in the same manner as in Example III-12 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.0%, 13.6, and 0 ppm, respectively.

[0385] [Example III-13] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) was added as a solvent in an amount corresponding to 20 wt% of the solid content of the 18 L can just opened. 17.07 g (49 mmol) of 9,9-bis(4-aminophenyl)fluorene (BAFL) was added and stirred to dissolve BAFL. Then, 22.92 g (50 mmol) of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) was added, and stirred at 80°C for 4 hours under a nitrogen flow. After cooling to room temperature, cyclobutanesulfonate was added to 20 wt% relative to (mass of solvent + mass of cyclobutanesulfonate) 100 wt%, and stirred for another hour to obtain a polyamide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.1%, 12.8, and 0 ppm, respectively.

[0386] [Comparative Example III-6] A polyamide imide solution was obtained in the same manner as in Example III-13 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.0%, 13.5, and 0 ppm, respectively.

[0387] [Example III-14] A 300 ml separable flask was purged with nitrogen, and dimethylacetamide (DMAc) as a solvent was added to the separable flask in an amount corresponding to 26 wt% of the solid content. 2.27 g (10 mmol) of 4,4'-diaminobenzanilide (DABAN) was added and stirred to dissolve DABAN. Then, 3.84 g (10 mmol) of norbutane-2-spiro-α-cyclopentanone-α'-spiro-2'-norbutane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) was added, and stirred at room temperature for 12 hours under a nitrogen flow. Then, 3-methylcyclobutanesulfonate was added to 20 wt% relative to (mass of solvent + mass of 3-methylcyclobutanesulfonate) 100 wt%, and stirred for another hour to obtain a polyamide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.4%, 1.5, and 0 ppm, respectively.

[0388] [Comparative Example III-7] A polyamide solution was obtained in the same manner as in Example III-14 except that 3-methylcyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 11.0%, 2.3, and 0 ppm, respectively.

[0389] [Example III-15] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) was added as a solvent in an amount corresponding to 15 wt% of the solid content of the 18 L can just opened. 5.6 g (49 mmol) of 1,4-cyclohexanediamine (1,4-CHDA) was added and stirred to dissolve. Then, 13.8 g (47.5 mmol) of 4,4'-diphthalic dianhydride (BPDA) and 0.7 g (1.5 mmol) of terephthalic acid dianhydride (TMHQ) were added, and stirred at 80°C for 1 hour under a nitrogen flow. After stirring at room temperature for 5 hours, cyclobutanesulfonate was added to 20 wt% relative to (mass of solvent + mass of cyclobutanesulfonate) 100 wt%, and stirred for another 1 hour to obtain a polyamide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.2%, 1.6, and 0 ppm, respectively.

[0390] [Example III-16] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) was added as a solvent in an amount corresponding to 15 wt% of the solid content of the 18 L can just opened. 5.6 g (49 mmol) of 1,4-cyclohexanediamine (1,4-CHDA) was added and stirred to dissolve. Then, 13.8 g (47.5 mmol) of 4,4'-diphthalic anhydride (BPDA) and 0.7 g (1.5 mmol) of trimellitic anhydride (TMHQ) were added, and stirred at 80°C for 1 hour under a nitrogen flow. After stirring at room temperature for 5 hours, the solution was added dropwise to water 6 times the amount of the solution while stirring to precipitate a polymer. The polymer was separated by filtration and then vacuum dried at 40°C for 24 hours using a vacuum dryer. Thereafter, the polymer was dissolved in cyclobutane sulfonate in a manner of 15 wt% to obtain a polyamide solution. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.2%, 1.6, and 600 ppm, respectively.

[0391] [Comparative Example III-8] A polyamide solution was obtained in the same manner as in Example III-15 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured to be 12.0%, 2.3, and 0 ppm, respectively.

[0392] [Example III-17] 168 g of γ-butyrolactone (GBL) and 15.2 g (100 mmol) of 3,5-diaminobenzoic acid (DABA) were added to a 500 ml separable flask and stirred to dissolve. Then, 38.4 g (100 mmol) of nordioxane-2-spiro-α-cyclopentanone-α'-spiro-2'-nordioxane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were installed in the flask, and water generated at 180°C was extracted from the Dean-Stark tube under a nitrogen flow while reacting for 2 hours under a nitrogen flow. The mixture was further heated at 180°C for 1 hour, and all the added toluene was extracted from the Dean-Stark tube. Cyclobutanesulfonate was added to reach 20 wt % relative to (mass of solvent + mass of cyclobutanesulfonate) 100 wt %, and the mixture was stirred for 1 hour to obtain a solution of soluble polyimide (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.5%, 1.4, and 0 ppm, respectively.

[0393] [Example III-18] A polyamide solution was obtained in the same manner as in Example III-17 except that the amount of cyclobutane sulfonate added was changed from 20 wt% to 50 wt%. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.5%, 1.4, and 600 ppm, respectively.

[0394] [Comparative Example III-9] In a 500 ml separable flask, 168 g of γ-butyrolactone (GBL) and 15.2 g (100 mmol) of 3,5-diaminobenzoic acid (DABA) were added and stirred to dissolve, and then 38.4 g (100 mmol) of nordioxane-2-spiro-α-cyclopentanone-α'-spiro-2'-nordioxane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were installed in the flask, and water generated at 180°C under a nitrogen flow was extracted from the Dean-Stark tube while reacting for 2 hours under a nitrogen flow. The mixture was further heated at 180°C for 1 hour, and all the added toluene was extracted from the Dean-Stark tube. The solution was then added dropwise to 6 times the amount of water as the solution while stirring to precipitate a polymer. After filtering and separating the polymer, the polymer was vacuum dried at 40°C for 24 hours using a vacuum dryer. Thereafter, the polymer was dissolved in cyclobutane sulfonate to a concentration of 15 wt% to obtain a soluble polyimide solution. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 2.5%, 1.4, and 1500 ppm, respectively.

[0395] [Comparative Example III-10] A polyamide solution was obtained in the same manner as in Example III-17 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.6%, 2.2, and 0 ppm, respectively.

[0396] [Example III-19] In a 500 ml separable flask, 130 g of N-methylpyrrolidone (NMP: water content 250 ppm) was added, 32.858 g (97.7 mmol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA) was added and stirred to dissolve, and then 22.936 g (60 mmol) of nordioxane-2-spiro-α-cyclopentanone-α'-spiro-2'-nordioxane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were installed in the flask, and the reaction was carried out for 2 hours under a nitrogen flow while the water generated at 180°C was extracted from the Dean-Stark tube. The mixture was then heated at 180°C for 1 hour, and all the added toluene was extracted from the Dean-Stark tube. After the solution was cooled to 50°C, 25 g of NMP was added, 11.704 g (40 mmol) of 4,4'-diphthalic anhydride (BPDA) was added, and the mixture was stirred at 50°C for 4 hours, cooled to room temperature, and 7.723 g (2 mmol) of polysiloxane diamine X-22-1660-B-3 manufactured by Shin-Etsu Chemical was added and stirred for 1 hour. Thereafter, cyclobutane sulfonate was added to 20 wt% relative to (mass of solvent + mass of cyclobutane sulfonate) 100 wt%, and the mixture was stirred for 1 hour to obtain a polyamide-soluble polyimide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.2%, 1.3, and 0 ppm, respectively.

[0397] [Example III-20] In a 500 ml separable flask, 130 g of N-methylpyrrolidone (NMP: water content 250 ppm) was added, 32.858 g (97.7 mmol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA) was added and stirred to dissolve, and then 22.936 g (60 mmol) of nordioxane-2-spiro-α-cyclopentanone-α'-spiro-2'-nordioxane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were installed in the flask, and the reaction was carried out for 2 hours under a nitrogen flow while the water generated at 180°C was extracted from the Dean-Stark tube. The mixture was then heated at 180°C for 1 hour, and all the added toluene was extracted from the Dean-Stark tube. After the solution was cooled to 50°C, 25 g of NMP was added, 11.704 g (40 mmol) of 4,4'-diphthalic anhydride (BPDA) was added, and the mixture was stirred at 50°C for 4 hours. The mixture was cooled to room temperature, and 7.723 g (2 mmol) of polysiloxane diamine X-22-1660-B-3 manufactured by Shin-Etsu Chemical was added and stirred for 1 hour. Thereafter, the solution was added dropwise to 6 times the amount of water as the solution while stirring, so that the polymer was precipitated. The polymer was separated by filtration, and then vacuum dried at 40°C for 24 hours using a vacuum dryer. Thereafter, the polymer was dissolved in cyclobutane sulfonate to a concentration of 15 wt%, and a solution of polyamide-soluble polyimide was obtained. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.2%, 1.3, and 500 ppm, respectively.

[0398] [Comparative Example III-11] A polyamide-soluble polyimide solution was obtained in the same manner as in Example III-19 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.0%, 2.2, and 0 ppm, respectively.

[0399] [Example III-21] A 500 ml separable flask was purged with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) in an amount corresponding to 15 wt% of the solid content of a freshly opened 18 L can was added as a solvent to the separable flask. 3.4576 g (30.3 mmol) of 1,4-cyclohexanediamine (1,4-CHDA) and 26.0326 g (70.7 mmol) of 4,4'-bis(aminophenoxy)biphenyl (BAPB) were added and stirred to dissolve. Thereafter, 30.5098 g (100.9 mmol) of decahydro-1,4:5,8-dimethylnaphthalene-2,3,6,7-tetracarboxylic dianhydride (DNDA) was added, and the mixture was stirred overnight at room temperature under a nitrogen flow. Then, cyclobutanesulfonate was added to a concentration of 20 wt % relative to (mass of solvent + mass of cyclobutanesulfonate) of 100 wt %, and the mixture was stirred for 1 hour to obtain a polyamide solution (hereinafter also referred to as varnish). The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured. The results were 2.1%, 1.8, and 0 ppm, respectively.

[0400] [Comparative Example III-12] A polyamide-soluble polyimide solution was obtained in the same manner as in Example III-21 except that cyclobutane sulfonate was not added. The varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity, YI, and degassing amount during reheating of the polyimide resin film were measured, and the results were 12.2%, 2.9, and 0 ppm, respectively. The results of the above-mentioned embodiments and comparative examples are summarized in Tables 11 to 13.

[0401] [Table 11] Example III Example 1 Example 2 Example 3 Comparative Example 1 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Comparative Example 2 Comparative Example 3 Anhydride (wt%) PMDA(85) ← ← ← ← ← ← ← ← ← ← ← ← 6FDA(15) ← ← ← ← ← ← ← ← ← ← ← ← Diamine (wt%) TFMB ← ← ← ← ← ← ← ← ← ← ← ← Solvent NMP ← ← ← ← ← ← ← ← ← ← ← ← Polymer structure PAA ← ← ← ← ← ← ← ← ← ← ← ← Aprotic polar substances with boiling point of 250℃~350℃ type Cyclobutane ← ← ← 3-Methylcyclobutane Benzophenone 2-Phenoxyethyl acetate Diphenyl carbonate Hexamethylenediamine Adiponitrile Dibutyl Sulfate Dimethyl Sulfide Diphenylsulfone Boiling point℃ 285 ← ← ← 276 305 260 302 263 295 250 238 379 Add to [quantity] 3 wt% 20 wt% 100 wt% 0 wt% 20 wt% 20 wt% 20 wt% 20 wt% 20 wt% 20 wt% 20 wt% 20 wt% 20 wt% In-plane film thickness uniformity 6.0% 2.0% 2.0% 12.0% 2.0% 4.2% 3.3% 3.0% 4.1% 4.0% 3.0% 12.0% 4.0% YI 7.9 7.3 7.3 8.1 7.6 7.4 7.6 7.5 7.6 7.5 7.6 8.1 7.5 Remaining aprotic polar substances in the cured film (ppm) 0 0 600 0 0 0 0 0 0 0 0 0 1500

[0402] [Table 12] Example III Embodiment 11 Comparative Example 4 Example 12 Comparative Example 5 Example 13 Comparative Example 6 Embodiment 14 Comparative Example 7 Embodiment 15 Example 16 Comparative Example 8 Acid Anhydride BPDA ← BPDA(80) ← BPAF ← CpODA ← BPDA(97) ← ← ODPA(20) ← TMHQ(3) ← ← Diamine APAB(80) ← APAB(80) ← BAFL ← DABAN ← CHDA ← ← 44DAS(20) ← 33DAS(20) ← Solvents NMP ← ← ← ← ← DMAc ← NMP ← ← Polymer structure PAA ← PI-PAA ← PAA ← PAA ← PAA ← ← Aprotic polar substances with boiling point of 250℃~350℃ type Cyclobutane ← Cyclobutane ← Cyclobutane ← 3-Methylcyclobutane ← Cyclobutane ← ← Boiling point℃ 285 ← 285 ← 285 ← 276 ← 285 ← ← Addition amount 20 wt% 0 wt% 20 wt% 0 wt% 20 wt% 0 wt% 20 wt% 0 wt% 20 wt% 100 wt% 0 wt% In-plane film thickness uniformity 2.2% 11.0% 2.3% 12.0% 2.1% 12.0% 2.4% 11.0% 2.2% 2.2% 12.0% YI 12.6 13.5 12.9 13.6 12.8 13.5 1.5 2.3 1.6 1.6 2.3 Remaining aprotic polar substances in the cured film (ppm) 0 0 0 0 0 0 0 0 0 600 0

[0403] [Table 13] Example III Embodiment 17 Embodiment 18 Comparative Example 9 Comparative Example 10 Embodiment 19 Embodiment 20 Comparative Example 11 Embodiment 21 Comparative Example 12 Acid Anhydride CpODA ← ← ← CpODA ← ← DNDA ← Diamine DABA ← ← ← 6FODA ← ← BAPB ← SiD ← ← Solvents GBL ← ← ← NMP ← ← ← ← Polymer structure PI ← ← ← PI-PAA ← ← PAA ← Aprotic polar substances with boiling point of 250C~350C type Cyclobutane ← ← ← Cyclobutane ← ← Cyclobutane ← Boiling point℃ 285 ← ← ← 285 ← ← 285 ← Addition amount 20 wt% 50 wt% 100 wt% 0 wt% 20 wt% 100 wt% 0 wt% 20 wt% 0 wt% In-plane film thickness uniformity 2.5% 2.5% 2.5% 12.6% 2.2% 2.2% 12.0% 2.1% 12.2% YI 1.4 1.4 1.4 2.2 1.3 1.3 2.2 1.8 2.9 Remaining aprotic polar substances in the cured film (ppm) 0 600 1500 0 0 500 0 0 0

[0404] As described above, the resin composition of the embodiment is softer and more fluid than the comparative example. When it is made into a polyimide resin film, the in-plane uniformity of the film thickness is improved and the YI is also reduced, and it is excellent in the properties required for display applications.

[0405] 2a: Lower base plate 2b: Sealing substrate 25: Organic EL structure 250a: Organic EL element emitting red light 250b: Organic EL element emitting green light 250c: Organic EL element emitting blue light 251: next wall (dam) 252: Lower electrode (anode) 253: Hole transport layer 254: Luminous layer 255: Upper electrode (cathode) 256:TFT 257: Contact hole 258: Interlayer insulation film 259: Lower electrode 261: Hollow

Claims

1. A resin composition comprising a polyamide-amide copolymer or polyamide, and (e) an amide catalyst, wherein the (e) amide catalyst is an imidazole compound, and the imidazole compound is N-tert-butoxycarbonylimidazolium (N-Boc-imidazole), wherein the polyamide-amide copolymer comprises a structural unit represented by the following general formula (1): [Chemical 1] {wherein, X1 and X3 represent tetravalent organic groups, X2 and X4 represent divalent organic groups, and n, m, and l are positive integers}, wherein the polyamide comprises a structural unit represented by the following general formula (3): [Chemical 7] {In the formula, X1 represents a tetravalent organic group, X2 represents a divalent organic group, and n is a positive integer}, and X4 in the above general formula (1) or X2 in (3) is selected from the following general formulas (A-4), (A-5), and (A-6): {In the formula, R8 to R11 independently represent a monovalent organic group or halogen with 1 to 20 carbon atoms, and h to k are independently integers from 0 to 4, Z2 represents a bonding group, and * represents a bonding part} {In the formula, R12 and R13 independently represent a monovalent organic group or halogen with 1 to 20 carbon atoms, l and m are independently integers from 0 to 4, and * represents a bonding part} {In the formula, R14 and R15 independently represent a monovalent organic group or halogen with 1 to 20 carbon atoms, n and 0 are independently integers from 0 to 4, and * represents a bonding part} At least one of the groups formed by the structures represented.

2. The resin composition of claim 1, wherein the content of the acetilimide catalyst (e) is 5 parts by mass or more relative to 100 parts by mass of the polyamide-acetilimide copolymer or polyamide.

3. The resin composition of claim 1 or 2, wherein the weight average molecular weight of the polyamide-imide copolymer or polyamide is 170,000 or more.

4. The resin composition of claim 1 or 2, wherein the content of the acetilimide catalyst (e) is 10 parts by mass or more relative to 100 parts by mass of the polyacetic acid-acetilimide copolymer or 100 parts by mass of the polyacetic acid.

5. The resin composition of claim 1 or 2, wherein the polyamide-imide copolymer or the polyamide has a weight average molecular weight of 220,000 or more.

6. The resin composition of claim 1 or 2 further comprises an aprotic polar substance with a boiling point of 250°C to 350°C.

7. The resin composition of claim 6, wherein the aforementioned aprotic polar substance is cyclobutane.

8. The resin composition of claim 1 or 2, wherein X3 in the above general formula (1) is selected from the following general formula (A-3): [Chemical 14] {wherein, R4 to R7 independently represent a monovalent organic group or halogen having 1 to 20 carbon atoms, d to g are independently integers from 0 to 4, Z1 represents a bonding group, and * represents a bonding part} the structure represented by the structure, the structure derived from 4,4'-oxyphthalic anhydride (ODPA), the structure derived from 4,4'-(hexafluoroisopropylidene)phthalic anhydride (6FDA), the structure derived from biphenyl tetracarboxylic acid dianhydride (BPDA), and the structure derived from 4,4'-biphenyl bis(trimethoxybenzoic acid monoester anhydride) (TAHQ) at least one of the group consisting of the following:

9. The resin composition of claim 1 or 2, wherein the content of the acetilimide catalyst (e) is in the range of 0.02 to 0.15 mol% relative to the polyamide-acetilimide copolymer or the repeating unit 1 of polyamide.

10. The resin composition of claim 1 or 2, wherein the diamine component constituting X2 in the above general formula (1) is different from the diamine composition or diamine type constituting X4.

11. The resin composition of claim 1 or 2, wherein the molar ratio (X2 / X1) of X1 and X2 contained in the above general formula (1) is 0.84 to 1.00, and the molar ratio of X3 and X4 (X4 / X3) contained in the above general formula (1) is 1.01 to 2.

00.

12. The resin composition of claim 1 or 2, wherein the molar ratio (number of moles of structural unit N: number of moles of structural unit M) of polyamide comprising X1 and X2 in the above general formula (1) is in the range of 60:40 to 95:

5.

13. The resin composition of claim 1 or 2, wherein the ratio of the polyamide structural unit N comprising X1 and X2 in all polymers contained in the resin composition is 60 to 95 moles.

14. The resin composition of claim 1 or 2, wherein the polyamide-imide copolymer is a block copolymer.

15. The resin composition of claim 1 or 2, wherein X1 and X3 in the above general formula (1) are derived from the tetravalent organic groups of aromatic tetracarboxylic acid dianhydrides having carbon numbers of 8 to 36.

16. A polyimide film formed by curing a resin composition as claimed in any one of claims 1 to 15.

17. A flexible device comprising a polyimide film as claimed in claim 16.

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