WO2022211086A1

WO2022211086A1 - Polyimide, resin composition, polyimide film, and production method therefor

Info

Publication number: WO2022211086A1
Application number: PCT/JP2022/016837
Authority: WO
Inventors: 聡加藤; 雄太佐藤; 健柏田; 隆行金田; 友裕頼末
Original assignee: 旭化成株式会社
Priority date: 2021-04-02
Filing date: 2022-03-31
Publication date: 2022-10-06
Also published as: JP7174199B1; KR20230147181A; JPWO2022211086A1; JP2024036637A; JP7436606B2; TW202246391A; JP2022190112A

Abstract

Provided is a resin composition comprising: a poly(amic acid)/imide copolymer including a structural unit L represented by formula (1) and having a structure represented by general formula (A-1) as the X₂ in general formula (1); an organic solvent; and at least one imidization catalyst selected from the group consisting of pyridine, triethylamine, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, and N-tert-butoxycarbonylimidazole (N-Boc-imidazole). (In the formulae, X₁ to X₄, n, m, l, R₁, R₂, a, b, and * are as defined in the specification.)

Description

Polyimide, resin composition, polyimide film, and method for producing the same

The present invention relates to a polyamic acid-imide, a resin composition containing the same, a polyimide resin film, a resin film, and a method for producing the same, which are used, for example, in the production of substrates for flexible devices.

Generally, polyimide resin films are used as resin films for applications that require high heat resistance. A general polyimide resin is produced by solution polymerization of an aromatic carboxylic dianhydride and an aromatic diamine to produce a polyimide precursor, which is then thermally imidized at a high temperature, or chemically imidized using a catalyst. It is a highly heat-resistant resin manufactured by

Polyimide resin is an insoluble and infusible super heat-resistant resin, and has excellent properties such as thermal oxidation resistance, heat resistance, radiation resistance, low temperature resistance, and chemical resistance. Therefore, polyimide resins are used in a wide range of fields including electronic materials. Examples of applications of polyimide resins in the field of electronic materials include insulating coating materials, insulating films, semiconductors, electrode protection films for thin film transistor liquid crystal displays (TFT-LCDs), and the like. Recently, in the field of display materials, adoption of polyimide resin as a flexible substrate that utilizes its lightness and flexibility in place of the conventionally used glass substrate is being studied.

When a polyimide resin is used as a flexible substrate, a varnish containing a polyimide resin or a precursor thereof and other components is applied onto a suitable support such as a glass substrate, and dried to form a film, After forming elements, circuits, etc. on the film, a step of peeling the film from the glass substrate is widely used. However, when producing a laminate having a polyimide resin, a heat treatment at a high temperature of 250° C. or higher is required for drying and imidizing the polyimide precursor. Due to this heat treatment, residual stress is generated in the laminate, and serious problems such as warping and peeling occur. This is because the coefficient of linear expansion of polyimide is larger than that of the material forming the support.

In order to reduce the residual stress in the laminate, the use of a polyimide resin whose thermal expansion coefficient is as small as that of glass has been studied. Polyimides formed from '-biphenyltetracarboxylic dianhydride (hereinafter also referred to as BPDA) and paraphenylenediamine are the most well known. It has been reported that this polyimide exhibits a very low coefficient of linear thermal expansion, although it depends on the film thickness and production conditions (Non-Patent Document 1).

However, general polyimide resins, including the polyimides described in the above literature, are colored brown or yellow due to high electron density, and therefore have low light transmittance in the visible light region, and therefore fields where transparency is required. It has been difficult to achieve a low enough yellowness index (YI value) for use in In addition, polyimide, which has a low coefficient of linear expansion, is known to tend to cause turbidity and cloudiness in the laminate due to its generally high molecular orientation, which causes deterioration in transmittance (Patent Document 2 ).

In general, regarding the yellowness index (YI value), for example, a solvent-soluble polyimide using a diamine having a trifluoromethyl group, or a polyimide using an alicyclic tetracarboxylic dianhydride or diamine has an extremely low yellow color. degree (YI value) and residual stress (Patent Literature 3 and Patent Literature 4).

WO2005/113647 Japanese Patent No. 6443579 WO2019/211972 WO2020/138360 Japanese Patent No. 4303623 Japanese Patent No. 5595381 Japanese Patent No. 6073528 JP-A-63-101424 JP-A-63-110219

As mentioned above, in order to apply polyimide resin as a colorless and transparent flexible substrate, it is necessary to achieve both excellent thermal properties and transparency, which are contradictory properties. In particular, recently, with the shift to LTPS (low-temperature polysilicon) as the device type of TFTs, there is a demand for the development of polyimide resins that are excellent in transparency even under heat history exceeding the conventional level.

Although the polyimide resin described in Patent Document 1, which is a general polyimide, showed a low coefficient of linear thermal expansion, it does not have sufficient transparency for use in the LTPS process at 400°C or higher. In addition, it is reported that the polyimide described in Patent Document 2 has a coefficient of linear expansion (hereinafter also referred to as "CTE") and excellent transparency by using a specific tetracarboxylic dianhydride and diamine. However, when heated to 400° C. or higher, the laminate becomes turbid and cloudy, and the haze (hereinafter also referred to as “HAZE value”) is not sufficient for use as a transparent substrate.

Furthermore, as a known technical idea, in order to achieve transparency, as described in Patent Document 3, an alicyclic acid dianhydride or diamine having no aromatic ring is used, or Intramolecular charge transfer (CT) transition is suppressed by using a diamine (eg, 2,2'-bis(trifluoromethyl)benzidine, hereinafter also referred to as TFMB) that is bulky and has a functional group that induces intramolecular twisting. It is known how to However, these polyimides with excellent transparency have insufficient heat resistance and thermal properties in the state of polyamic acid, and in order to obtain high transparency, it is necessary to use a solvent-soluble polyimide resin that has completed imidation during solution polymerization. However, these polyimides have a large coefficient of linear expansion when made into a film, have poor thermal stability in a high temperature range of 430° C. or higher, and are not sufficiently soluble in solvents.

Mixing or copolymerization of polyimide and polyamic acid has been studied in order to achieve both thermal properties and transparency, which are contradictory properties. It is known to cause the occurrence of , and was not suitable as a transparent substrate (Patent Document 5). This is because the heat-resistant polyimide has a high planarity and a rigid skeleton, and thus is difficult to be compatible with the soluble polyimide having a bending group when formed into a film, resulting in phase separation.

Patent Document 4 discloses that storage stability and moldability can be improved by partially coexisting an imide structure and an amide structure in the molecule. However, as confirmed by the present inventors, the polyamic acid-imide resin composition described in Patent Document 4 has poor heat resistance, and in the heat history of 430 ° C. or higher in the LTPS process, the yellowness index (YI value) and haze It turned out that the degree (HAZE) deteriorates remarkably. The main reason for this is that polyimide and polyamic acid have a common monomer skeleton. It has been difficult to achieve a balance between the conflicting properties of properties and transparency.

In addition, Patent Document 6 discloses that the imide structure and the amic acid structure can be partially coexisted in the molecule, and the bending structure and transparency can be improved by using an alicyclic diamine. However, the present inventors have confirmed that the block polyimide described in Patent Document 6 significantly deteriorates in yellowness (YI value) and haze (HAZE) in the heat history of 430 ° C. or higher in the LTPS process. Do you get it. The main reason for this is that an alicyclic diamine is used as the diamine, and while the alicyclic diamine is excellent in bending resistance, the alicyclic is decomposed in a heat history of 430 ° C. or higher. Therefore, it was difficult to achieve both heat resistance and bending resistance.

Furthermore, general polyimide resins, including the polyimides described in Patent Documents 7 to 9 above, are colored brown or yellow due to high electron density, and therefore have low light transmittance in the visible light region, and therefore transparency. It was difficult to use it in the required fields.
In addition, when forming a polyimide resin film using a conventional resin composition, in the curing step (heated to about 400 ° C.), the fluidity of the resin composition is not sufficient, and the resulting polyimide resin film has a thickness of In-plane uniformity was found to be insufficient.
As described above, conventional polyimide resin films do not have sufficient properties required for use as colorless transparent substrates for displays, such as in-plane uniformity of film thickness and yellowness index (YI value).

In view of such circumstances, the present invention has been made to solve the above problems. By block copolymerizing the polyamic acid - imide copolymer resin composition that achieves both transparency and heat resistance, or block copolymerization of polyimide with excellent bending resistance and transparency and polyamic acid with excellent heat resistance A polyamic acid-imide copolymer resin composition that achieves both transparency, heat resistance, and bending resistance, and a polyimide or polyimide copolymer using the same, or a polyimide after infrared (IR) curing. A resin composition containing a polyamic acid or a polyamic acid-imide copolymer using 4-amino-3-fluorophenyl-4-aminobenzoate (APAB), which can reduce film defects, or a film thickness A resin composition or a polyimide resin film capable of obtaining a polyimide resin film having excellent in-plane uniformity and a low yellowness index (YI value), a method for producing the same, a method for producing a display, a method for producing a laminate, and a flexible product An object of the present invention is to provide a device manufacturing method.

The present inventors have made intensive research and repeated experiments in order to solve the above problems, and as a result, polyimide films obtained by curing a resin composition containing a polyamic acid-imide copolymer containing a specific structure are excellent. high transparency, haze, heat resistance, and coefficient of linear expansion, low residual stress and bending resistance, or reduced defects in polyimide films upon infrared (IR) curing, and/or By including an aprotic polar substance with a boiling point of 250 ° C. to 350 ° C. in the resin composition, the resin becomes soft and fluid, and when it is formed into a polyimide resin film, the in-plane uniformity of the film thickness is improved. improved and the YI could also be reduced, and based on these findings, the present invention was completed. That is, the invention is as follows.

<1>
The following general formula (1):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n, m, and l are positive integers, and As X ₂ in general formula (1), the following general formula (A-1):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid-imide copolymer containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, and the (e) imidization catalyst is an imidazole compound, a pyridine compound, and A resin composition comprising at least one selected from the group consisting of tertiary amine compounds.
<2>
The imidazole compound is 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 is at least one selected from the group consisting of
The pyridine compound is at least one selected from the group consisting of 4-dimethylaminopyridine, 2,2'-bipyridyl, nicotinic acid, isoquinoline, pyridine, and 2-methylpyridine, and/or the tertiary amine The 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 is one
Item 1. The resin composition according to item 1.
<3>
3. The resin composition according to item 1 or 2, wherein (e) the imidization catalyst is the imidazole compound.
<4>
4. The resin composition according to any one of items 1 to 3, wherein the content of (e) the imidization catalyst is 5 parts by mass or more with respect to 100 parts by mass of the polyamic acid-imide copolymer.
<5>
The following general formula (1):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
and (d) an organic solvent, wherein the polyamic acid-imide copolymer has a weight average molecular weight of 170,000 or more.
<6>
5. The resin composition according to any one of items 1 to 4, wherein the polyamic acid-imide copolymer has a weight average molecular weight of 170,000 or more.
<7>
The following general formula (3):

{Wherein, X ₁ represents a tetravalent organic group, X ₂ represents a divalent organic group, n is a positive integer, and X ₂ in the general formula (3) , the following general formula (A-1):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
(d) an organic solvent and (e) an imidization catalyst, wherein the (e) imidization catalyst is 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-un Decylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1H-imidazole, 4-dimethylaminopyridine, 2,2'-bipyridyl, nicotinic acid, isoquinoline, pyridine, 2-methylpyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and at least one selected from the group consisting of triethylamine , resin composition.
<8>
The following general formula (3):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, wherein the (e) imidization catalyst is an imidazole compound, and the (e) imidization catalyst content is 5 parts by mass or more with respect to 100 parts by mass of the polyamic acid.
<9>
The following general formula (3):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, wherein the (e) imidization catalyst is an imidazole compound, and the weight average molecular weight of the polyamic acid is 170,000 or more, the resin composition.
<10>
9. The resin composition according to item 7 or 8, wherein the polyamic acid has a weight average molecular weight of 170,000 or more.
<11>
The content of the (e) imidization catalyst is 10 parts by mass or more with respect to 100 parts by mass of the polyamic acid-imide copolymer or 100 parts by mass of the polyamic acid. The described resin composition.
<12>
The resin according to any one of items 1 to 11, wherein the (e) imidization catalyst is an imidazole compound containing N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and/or 1-methylimidazole. Composition.
<13>
13. The resin composition according to any one of items 1 to 12, wherein the polyamic acid-imide copolymer or the polyamic acid has a weight average molecular weight of 220,000 or more.
<14>
14. The resin composition according to any one of items 1 to 13, further comprising an aprotic polar substance having a boiling point of 250°C to 350°C.
<15>
15. The resin composition according to item 14, wherein the aprotic polar substance is sulfolane.
<16>
X ₄ in the general formula (1) or X ₂ in (3) is represented by the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R ₈ to R ₁₁ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen, and h to k each independently represent an integer of 0 to 4, Z ₂ indicates the linking group and * indicates the linking point}

{wherein R ₁₂ and R ₁₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a joint}

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and о each independently represent an integer of 0 to 4; * indicates a joint}
The resin composition according to any one of items 1 to 15, which is at least one selected from the group consisting of structures represented by
<17>
X ₃ in the general formula (1) is represented by the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
A structure derived from 4,4′-oxydiphthalic dianhydride (ODPA), a structure derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), biphenyltetracarboxylic acid di Items 1 to 6, which are at least one selected from the group consisting of a structure derived from anhydride (BPDA) and a structure derived from 4,4′-biphenylbis(trimellitic acid monoester acid anhydride) (TAHQ) , the resin composition according to any one of 11 to 16.
<18>
Items 1 to 6 and 11 to 17, wherein the content of the (e) imidization catalyst is in the range of 0.02 to 0.15 mol% relative to 1 mol of the repeating unit of the polyamic acid-imide copolymerization. The resin composition according to any one of the items.
<19>
The following general formula (1):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n, m, and l are positive integers, and X ₁ and X ₂ is called structural unit N, and the structural unit made up of X ₃ and X ₄ is called structural unit M,
When X ₂ is a group derived from 4-amino-3-fluorophenyl-4-aminobenzoate, the following structures 1 and 2:
1. When X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X ₂ is 4,4′-diaminodiphenyl sulfone and/or 2 , 2′-bis(trifluoromethyl)benzidine; X ₃ is a group derived from norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride ;
except for}
and the following general formula (A-1) as X ₂ :

{wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; * indicates a joint}
Or the following general formula (A-2):

{In the formula, 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. * indicates a joint}
Polyamic acid-imide copolymer characterized by having a structure represented by.
<20>
X ₃ in the general formula (1) is represented by the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of Polyamic acid-imide copolymer according to item 19, which is at least one kind of polyamic acid-imide copolymer.
<21>
X ₄ in the general formula (1) is the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R ₁₂ and R ₁₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a bond, provided that when X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A- 5) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and о each independently represent an integer of 0 to 4; * indicates a joint}
The polyamic acid-imide copolymer according to item 19 or 20, which is at least one selected from the group consisting of structures represented by.
<22>
The following general formula (1):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n, m, and l are positive integers, and X ₁ and X ₂ is called structural unit N, the structural unit made up of X ₃ and X ₄ is called structural unit M, and X ₄ is 4,4′-diaminodiphenyl sulfone and/or excluding groups derived from 2,2′-bis(trifluoromethyl)benzidine}
and as X ₃ , the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of A polyamic acid-imide copolymer characterized by comprising at least one of
<23>
X ₄ in the general formula (1) is represented by the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R ₁₂ and R ₁₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; i and j each independently represent an integer of 0 to 4; * indicates a bond, provided that when X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A- 5) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and о each independently represent an integer of 0 to 4; * indicates a joint}
23. Polyamic acid-imide copolymer according to item 22, which is at least one selected from the group consisting of structures represented by
<24>
The diamine component constituting X ₂ and the diamine component constituting X ₄ in the general formula (1) are different in either diamine composition or diamine species, according to any one of items 19 to 23. Polyamic acid-imide copolymer.
<25>
X ₁ in the general formula (1) is a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and 4,4'-biphenyl The polyamic acid-imide copolymer according to any one of items 19 to 24, which is at least one selected from the group consisting of structures derived from bis(trimellitic monoester acid anhydride) (TAHQ).
<26>
The molar ratio (X ₂ /X ₁ ) of X ₁ and X ₂ contained in the general formula (1) is 0.84 to 1.00, and X ₃ and X contained in the general formula (1) ₄ Polyamic acid-imide copolymer according to any one of items 19 to 25, wherein the molar ratio of (X ₄ /X ₃ ) is 1.01 to 2.00.
<27>
The molar ratio of the polyamic acid structural unit N composed of X ₁ and X ₂ and the polyimide structural unit M composed of X ₃ and X ₄ in the general formula (1) (number of moles of structural unit N: structure The polyamic acid-imide copolymer according to any one of items 19 to 26, wherein the number of moles of units M) is in the range of 60:40 to 95:5.
<28>
A resin composition containing the polyamic acid-imide copolymer according to any one of items 19 to 27 and (d) an organic solvent.
<29>
29. The resin composition according to item 28, wherein the proportion of the polyamic acid structural unit N composed of X ₁ and X ₂ is 60 to 95 mol % in the total polymer contained in the resin composition.
<30>
30. The resin composition according to item 28 or 29, further comprising (e) an imidization catalyst.
<31>
The following general formula (2):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n and m are positive integers, and X ₁ and X ₂ is called structural unit N, and the structural unit made up of X ₃ and X ₄ is called structural unit M, and X ₂ is 4-amino-3-fluorophenyl-4-aminobenzoate If it is a group derived from, the following structures 1 and 2:
1. When X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X ₂ is 4,4′-diaminodiphenyl sulfone and/or 2 , 2′-bis(trifluoromethyl)benzidine; and 2. X ₃ is a group derived from norbornane-2-spiro-α-cyclopentanone a-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride be;
except for}
and the following general formula (A-1) as X ₂ :

{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 bond}
Polyimide copolymer characterized by having a structure represented by.
<32>
X ₃ in the above general formula (2) is represented by the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of 32. The polyimide copolymer according to item 31, which is at least one kind of polyimide copolymer.
<33>
The following general formula (2):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n and m are positive integers, and X ₁ and X ₂ A structural unit composed of is called structural unit N, a structural unit composed of X ₃ and X ₄ is called structural unit M, and X ₄ is 4,4′-diaminodiphenylsulfone, 2,2′- excluding groups derived from bis(trifluoromethyl)benzidine}
and as X ₃ , the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of A polyimide copolymer comprising at least one of
<34>
X ₄ in the general formula (2) is the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R ₁₂ and R ₁₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a bond, and when X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A-5 ) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and о each independently represent an integer of 0 to 4; * indicates a joint}
34. The polyimide copolymer according to item 33, which is at least one selected from the group consisting of structures represented by:
<35>
X ₁ in the general formula (2) is a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and 4,4'-biphenyl The polyimide copolymer according to any one of items 31 to 34, which is at least one selected from the group consisting of structures derived from bis(trimellitic monoester acid anhydride) (TAHQ).
<36>
The molar ratio (X ₂ /X ₁ ) of X ₁ and X ₂ contained in the general formula (2) is 0.84 to 1.00, and X ₃ and X contained in the general formula (2) ₄ Polyimide copolymer according to any one of items 31 to 35, wherein the molar ratio of (X ₄ /X ₃ ) is 1.01 to 2.00.
<37>
The molar ratio of the polyimide structural unit N composed of X ₁ and X ₂ and the polyimide structural unit M composed of X ₃ and X ₄ in the general formula (2) (number of moles of structural unit N: number of structural units M number of moles) is in the range of 60:40 to 95:5, the polyimide copolymer according to any one of items 31 to 36.
<38>
Having 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),
A resin composition comprising an aprotic polar substance having a boiling point of 250° C. to 350° C.:

{wherein P ₁ represents a divalent organic group, P ₂ represents a tetravalent organic group, and p represents a positive integer}

{wherein P ₁ represents a divalent organic group, P ₂ represents a tetravalent organic group, and p represents a positive integer}.
<39>
A resin composition containing a polyimide represented by the following general formula (II), a solvent, and an aprotic polar substance having a boiling point of 250° C. to 350° C.:

{wherein P ₁ represents a divalent organic group, P ₂ represents a tetravalent organic group, and p represents a positive integer}.

According to the present invention, a polyamic acid-imide copolymer having both transparency and heat resistance, and a resin composition containing the same are provided, and have excellent transparency, haze, heat resistance and coefficient of linear expansion. A polyimide film and a method for producing the same can also be provided, and/or polyimide having excellent bending resistance and transparency and polyamide having excellent heat resistance using an aromatic dianhydride having a fluorene skeleton as a main component. A polyamic acid-imide copolymer resin composition, polyimide, or polyimide film that can provide block copolymerization with an acid, and thus has both transparency and heat resistance, further low residual stress and bending resistance, and Methods for their manufacture can also be provided. Then, polyamic acid or polyamic acid-imide copolymer using 4-amino-3-fluorophenyl-4-aminobenzoate (APAB), which makes it possible to reduce the defects of the polyimide film when cured with infrared rays (IR) A resin composition containing a polymer is provided, and thus a polyimide film with reduced defects and a method for producing the same can be provided. Further, according to the present invention, a resin composition, a method for producing a polyimide resin film, and a method for producing a display are capable of obtaining a polyimide resin film having excellent in-plane uniformity of film thickness and a low yellowness index (YI value). , a method for manufacturing a laminate and a method for manufacturing a flexible device.

FIG. 1 is a schematic diagram showing the structure above a polyimide substrate of a top emission type flexible organic EL display as an example of a display according to one embodiment of the present invention.

Exemplary embodiments of the present invention (hereinafter abbreviated as "embodiments") will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. In addition, unless otherwise specified, the characteristic values described in the present disclosure are values measured by the method described in the [Examples] section or a method understood to be equivalent thereto by a person skilled in the art. Intend.

<Resin composition>
The resin composition provided by one aspect of the present invention contains (a) polyamic acid and/or (b) polyimide, (c) polyamic acid-imide copolymer, polyimide or polyamic acid, and (d) organic solvent and may optionally contain other components such as (e) an imidization catalyst.

Below, each component will be explained in order.

<First embodiment>
(A) Polyamic acid-imide copolymer A first embodiment of the present disclosure is
The following general formula (1):

{Wherein, X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, n, m, and l are positive integers, and X ₁ and X2 is called a structural unit _N _, and a structural unit composed of X3 and _X4 is called a structural unit M}
and the following general formula (A-1) as X ₂ :

{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 * indicates a bond}
A polyamic acid-imide copolymer characterized by having a structure represented by is provided.

Further, specific examples of the structure represented by general formula (A-2) include the following general formula (A-2a):

{Wherein, R ₃ , c and * are as defined in general formula (A-2)}
can be mentioned.

The polyamic acid-imide copolymer according to the first embodiment can be used as a polyimide precursor, and when it is used to form a polyimide film, it has a low coefficient of linear expansion, a low residual stress, and a haze ( Haze value) and yellowness (YI value) are small. In addition, the polyamic acid-imide copolymer according to the first embodiment has a small yellowness (YI value) in a high temperature region and a low haze (Haze value) when a polyimide film is formed using it. small. From this point of view, the polyamic acid-imide copolymer according to the first embodiment preferably has a weight average molecular weight of 170,000 or more, and/or X ₂ is 4-amino-3-fluorophenyl- When the group is derived from 4-aminobenzoate, the following structures 1 and 2:
Configuration 1. When X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X ₂ is 4,4′-diaminodiphenyl sulfone and/or 2 , a group derived from 2′-bis(trifluoromethyl)benzidine; X ₃ is a group derived from norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride ;
is preferably excluded.

<Second embodiment>
A second embodiment of the present disclosure is
Including the structural unit L represented by the above general formula (1), and as X ₁ and/or X ₃ , the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
, a structure derived from 4,4′-oxydiphthalic dianhydride (ODPA), a structure derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), biphenyltetracarboxylic acid di characterized by containing at least one selected from the group consisting of a structure derived from anhydride (BPDA) and a structure derived from 4,4′-biphenylbis(trimellitic acid monoester acid anhydride) (TAHQ) A polyamic acid-imide copolymer is provided.

The polyamic acid-imide precursor according to the second embodiment has a low linear expansion coefficient, low residual stress, excellent bending resistance, and high haze (Haze value) and yellowness (YI value) when made into a polyimide film. ) is small. In addition, the polyamic acid-imide copolymer according to the second embodiment has a low yellowness (YI value) and a low haze (Haze value) in a high temperature range when formed into a polyimide film. In the second embodiment, from such a viewpoint, X ₃ is at least one selected from the group consisting of a structure represented by general formula (A-3), a structure derived from ODPA, and a structure derived from 6FDA and/or X ₄ is 4,4 when X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) It is preferred to exclude groups derived from '-diaminodiphenyl sulfone and/or 2,2'-bis(trifluoromethyl)benzidine.

<Third Embodiment>
In the third embodiment of the present disclosure, the resin composition is a polyimide precursor represented by the following general formula (I), or a polyimide precursor skeleton represented by the following general formula (I) and the following general formula (II ) and contains an aprotic polar substance with a boiling point of 250 ° C. to 350 ° C., or the resin composition is a polyimide represented by the following general formula (II) , a solvent, and an aprotic polar substance having a boiling point of 250°C to 350°C.
(polyimide precursor)

{In the formula, P ₁ represents a divalent organic group, P ₂ represents a tetravalent organic group, and p represents a positive integer. }
(polyimide resin)

{In the formula, P ₁ represents a divalent organic group, P ₂ represents a tetravalent organic group, and p represents a positive integer. }

The polyimide according to the third embodiment is obtained by thermal imidization of a polyimide precursor, and can also be chemically imidized. Thermal imidization is preferred from the viewpoint of the transparency of the resulting polyimide film. Moreover, the resin composition can contain an imidization accelerator.

The resin composition according to the third embodiment contains an aprotic polar substance with a boiling point of 250° C. to 350° C., so that in the curing step (heating step), the aprotic polar substance is heated to, for example, 250° C. As described above, it plays a role as a plasticizer at high temperatures, and the resin becomes soft and fluid, and when it is made into a polyimide resin film (hereinafter also referred to as a polyimide film), the in-plane uniformity of the film thickness is improved. At the same time, YI can also be reduced.

The resin composition according to the third embodiment may further contain a solvent such as an aprotic solvent. This aprotic solvent should be distinguished from the aprotic polar substance with a boiling point of 250°C to 350°C.

Here, the P2 groups in general formulas (I) and ( _II ) are acid anhydride residues, which may be the same or different. Also, the P ₁ groups in general formulas (I) and (II) are diamine residues, which may be the same or different.

<Fourth embodiment>
(B) Polyamic acid In the fourth embodiment of the present disclosure, the following general formula (3):

(wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid containing a structural unit represented by or a polyamic acid-imide copolymer containing a structural unit derived from it, which is blended with a specific (e) imidization catalyst, or the weight average molecular weight of the polyamic acid is 170,000 or more, or a polyamic acid-imide copolymer containing structural units derived therefrom. The polyamic acid according to the fourth embodiment or the polyamic acid-imide copolymer containing structural units derived therefrom can reduce defects in polyimide films when cured with infrared rays (IR).

The features according to the first, second, third and fourth embodiments may be combined or interchanged. Common configurations, preferred configurations, etc. of the first, second, third and fourth embodiments will be described below.

(a) <Embodiment of polyamic acid moiety>
The polyamic acid portion constituting the polyamic acid-imide copolymer of the present invention is the portion represented by the structural unit N in the general formula (1).

In the general formula (1), X ₁ is a tetravalent organic group, and multiple X ₁ 's present in the polyimide precursor may be the same or different. X ₁ is exemplified by a tetravalent organic group derived from the following tetracarboxylic dianhydride.

The tetracarboxylic dianhydrides include aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms, aliphatic tetracarboxylic dianhydrides having 6 to 50 carbon atoms, and lipids having 6 to 36 carbon atoms. A cyclic tetracarboxylic dianhydride can be exemplified. Among these, aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms are preferred from the viewpoint of yellowness in a high temperature range. The number of carbon atoms as used herein also includes the number of carbon atoms contained in the carboxyl group.

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 Acid 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′-diphenylsulfonetetracarboxylic dianhydride (hereinafter also referred to as DSDA), 2,2′,3,3 '-biphenyltetracarboxylic dianhydride, methylene-4,4-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2-propylidene-4,4'-diphthalic acid acid 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), p-phenylene bis(trimellitate) anhydride) (hereinafter also referred to as TAHQ) thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2- (3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3- (3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-di Carboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bi Su (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-anthracene Examples include tetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, and the like.

Examples of aliphatic tetracarboxylic dianhydrides having 6 to 50 carbon atoms include ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, and the like;
Alicyclic tetracarboxylic dianhydrides having 6 to 36 carbon atoms, such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1,2, 3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclopentanonebisspironorbornanetetracarboxylic dianhydride (hereinafter also referred to as CPODA), 3, 3',4,4'-bicyclohexyltetracarboxylic 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-ethylidene-4,4'-bis(cyclohexane- 1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-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 anhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, REL-[1S,5R,6R]-3-oxabicyclo[3,2 ] Octane-2,4-dione-6-spiro-3′-(tetrahydrofuran-2′,5′dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4 -tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-3,4-dicarboxylic anhydride (phenyl) ether, and the like.

In one preferred embodiment, X ₁ is pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4′-biphenylbis(trimellitic monoester anhydride) (TAHQ) , 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4′ - derived from at least one selected from the group consisting of oxydiphthalic anhydride (ODPA) and cyclopentanonebisspironorbornanetetracarboxylic dianhydride (CPODA).

PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA are preferable from the viewpoint of the balance of linear expansion coefficient (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature range, and BPDA, TAHQ, and ODPA are more preferred.

The polyamic acid-imide copolymer, for example, as a polyimide precursor, may be obtained by using a dicarboxylic acid in addition to the above-mentioned tetracarboxylic dianhydride within a range that does not impair its performance. By using such a precursor, it is possible to adjust various performances such as improvement in mechanical elongation, improvement in glass transition temperature and reduction in yellowness in the resulting film. Such dicarboxylic acids include dicarboxylic acids having aromatic rings and alicyclic dicarboxylic acids. At least one compound selected from the group consisting of aromatic dicarboxylic acids having 8 to 36 carbon atoms and alicyclic dicarboxylic acids having 6 to 34 carbon atoms is particularly preferred. The number of carbon atoms as used herein also includes the number of carbon atoms contained in the carboxyl group. Among these, dicarboxylic acids having an aromatic ring are preferred.

Specific examples of dicarboxylic acids include isophthalic acid, terephthalic acid, 4,4′-biphenyldicarboxylic acid, 3,4′-biphenyldicarboxylic acid, 3,3′-biphenyldicarboxylic acid, and 1,4-naphthalenedicarboxylic acid. acid, 2,3-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3,4'-sulfonylbisbenzoic acid, 3,3' -sulfonylbisbenzoic acid, 4,4'-oxybisbenzoic acid, 3,4'-oxybisbenzoic acid, 3,3'-oxybisbenzoic acid, 2,2-bis(4-carboxyphenyl)propane, 2,2- bis(3-carboxyphenyl)propane, 2,2'-dimethyl-4,4'-biphenyldicarboxylic acid, 3,3'-dimethyl-4,4'-biphenyldicarboxylic acid, 2,2'-dimethyl-3, 3′-biphenyldicarboxylic 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, 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-sik Rohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4′-benzophenonedicarboxylic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, etc.; and described in WO 2005/068535 pamphlet and 5-aminoisophthalic acid derivatives of. When these dicarboxylic acids are actually copolymerized with polymers, they may be used in the form of acid chlorides or active esters derived from thionyl chloride or the like.

In the above general formula (1), X ₂ is a divalent organic group, preferably a structure represented by the following general formula (A-1) or 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), and a diamine-derived structure represented by the following general formula (B-1), or BAFL, Structures derived from BFAF, BAOFL, 44DAS, 33DAS, 44ODA, 34ODA, etc. are preferred. X ₂ is preferably a structure derived from 4-aminophenyl-4-aminobenzoate from the viewpoint of yellowness (YI value) in a high temperature region, and 4-amino-3- from the viewpoint of haze (HAZE value). At least one structure derived from fluorophenyl-4-aminobenzoate (APAB), paraphenylenediamine (pPD), BAFL, and BFAF is preferred.

In one aspect, the structure of X ₂ in general formula (1) is the following general formula (A-1):

{wherein R ₁ and R ₂ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; * indicates a joint}
is represented by

Here, R ₁ and R ₂ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when a and/or b=0), or halogen. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group, and a and/or b = 0, it may be hydrogen, or halogens include fluorine and the like. Among these, from the viewpoint of yellowness (YI value) in a high temperature region, hydrogen and / or phenyl groups are preferable, and from the viewpoint of haze (Haze value), hydrogen, methyl group, and the group consisting of fluorine at least one is preferred.

Here, a and b are not limited as long as they are integers from 0 to 4. Among these, an integer of 0 to 2 is preferable from the viewpoint of yellowness (YI value) and residual stress, and 0 is particularly preferable from the viewpoint of yellowness (YI value) in a high temperature region.

In one aspect, the structure of X ₂ in general formula (1) is the following general formula (A-6):

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and o each independently represent an integer of 0 to 4; * indicates a joint}
is represented by

Here, R ₁₄ and R ₁₅ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when n and o=0), or halogen. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group, and the like. In the case of 0, it may be hydrogen, and halogens include fluorine and the like. Among these, from the viewpoint of yellowness (YI value) in a high temperature region, hydrogen and / or phenyl groups are preferable, and from the viewpoint of haze (Haze value), hydrogen, methyl group, and the group consisting of fluorine at least one is preferred.

Here, n and о are not limited as long as they are integers from 0 to 4. Among these, an integer of 0 to 2 is preferable from the viewpoint of yellowness (YI value) and residual stress, and 0 is particularly preferable from the viewpoint of yellowness (YI value) in a high temperature region.

In one aspect, the structure of X ₂ in general formula (1) is the following general formula (A-2):

{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 * indicates a bond}
is represented by

Here, each R ₃ is not limited as long as it is independently 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 group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group, and when c=0 may be hydrogen, or halogens include fluorine and the like. Among these, hydrogen is preferable from the viewpoint of yellowness (YI value) in a high temperature range, and methyl group and/or fluorine is preferable from the viewpoint of haze (Haze value).

Here, c is not limited as long as it is an integer from 0 to 4. Among these, an integer of 0 to 2 is preferable from the viewpoint of yellowness (YI value) and residual stress, and 0 is particularly preferable from the viewpoint of yellowness (YI value) in a high temperature region.

In one aspect, the structural unit represented by general formula (A-1) has the following general formula (B-1):

{Wherein, R ₁ , R ₂ , a and b are defined in the same manner as in general formula (A-1)}
Derived from the diamine represented by

As the diamine represented by the general formula (B-1), more specifically, 4-aminophenyl-4-aminobenzoate (hereinafter also referred to as APAB) and 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 referred to as 2F -APAB), 3-fluoro-4-aminophenyl-4-aminobenzoate (hereinafter also referred to as 3F-APAB), 3-methyl-4-aminophenyl-3-methyl-4-aminobenzoate (hereinafter referred to as 3 , also referred to as 3Me-APAB), etc., and from the viewpoint of yellowness (YI value) in a high temperature region, APAB is preferable, and from the viewpoint of reducing haze (Haze value), APAB, 3Me- APAB and 3F-APAB are preferred.

In one aspect, the structural unit represented by general formula (A-2) has the following general formula (B-2):

{Wherein, R ₃ and c are defined in the same manner as in general formula (A-2)}
Derived from the diamine represented by

More specific examples of the diamine represented by the general formula (B-2) include p-phenylenediamine (pPD), m-phenylenediamine, 3,5-diaminobenzoic acid, and the like. pPD is preferable from the viewpoint of heat resistance at .

Polyamic acid, polyimide, polyamic acid-imide copolymer, and polyimide copolymer, respectively, within a range that does not impair yellowness, haze, residual stress, etc., the general formula (B-1) and the general formula ( Other diamines can be used in addition to the diamines represented by B-2) or in place of the diamines represented by general formulas (B-1) and (B-2).

Other diamines include, for example, 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., and one selected from these It is preferred to use the above. The content of the other diamines in the total diamine is preferably 20 mol % or less, particularly preferably 10 mol % or less. On the other hand, from the viewpoint of heat resistance at high temperatures, it is preferable that the diamine used does not contain a silicone diamine. Examples thereof include "X-22-9409" and "X-22-1660B-3" manufactured by Shin-Etsu Chemical Co., Ltd., which are commercially available as silicone-based diamines.

The molar ratio (X ₂ /X ₁ ) between X ₁ and X ₂ in the polyamic acid moiety contained in the general formula (1) is preferably 0.84 to 1.00 or 0.85 to 1.2, and 0 0.90 to 1.1 is more preferred, and 0.92 to 1,00 is even more preferred. When X ₁ /X ₂ is 0.84 or more or 0.85 or more, the residual stress is low and the YI is low. When X ₁ /X ₂ is 1.2 or less or 1.00 or less, the mechanical properties such as elongation and breaking strength are excellent.

The weight average molecular weight (Mw) of the polyamic acid and the polyamic acid part is preferably 1,000 or more, more preferably 1,000 to 300,000 or 2,639 to 300,000, 10,000 to 200,000 or 10 ,000 to 250,000 are more preferred, and 30,000 to 200,000 are particularly preferred. When the weight average molecular weight is 1,000 or more, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI is low. When the weight-average molecular weight is 300,000 or less, the weight-average molecular weight can be easily controlled during the synthesis of the polyamic acid, a resin composition having an appropriate viscosity can be obtained, and the coating properties of the resin composition are improved. Further, when the Mw of the polyamic acid and the polyamic acid portion is 170,000 or more, transparency, haze, heat resistance and coefficient of linear expansion tend to be excellent, and Mw of 220,000 or more is more preferable. This tendency is remarkable when X ₂ in general formula (1) has the structure represented by general formula (A-1) above. In the present disclosure, the weight average molecular weight is a value obtained as a standard polystyrene conversion value using gel permeation chromatography (hereinafter also referred to as GPC).

(b) <Embodiment of polyimide part>
The polyimide moiety constituting the polyamic acid-imide copolymer of the present invention is the moiety represented by the structural unit M in the general formula (1).

In the general formula (1), X ₃ is a tetravalent organic group, preferably the structure represented by the following general formula (A-3), or 4,4'-oxydiphthalic dianhydride (ODPA ), and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), which is a structure derived from at least one selected from tetracarboxylic acid described in <Embodiment of polyamic acid moiety> A tetravalent organic group derived from an acid dianhydride can be used. In addition, a plurality of X ₃ present in the polyamic acid-imide copolymer that can be used as a polyimide precursor may be the same or different, and may be the same or different from X ₁ . good too.

X ₃ is preferably a structure derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) from the viewpoint of yellowness (YI value) in a high temperature region, and residual stress From the point of view, structures derived from ODPA are preferred.

Tetracarboxylic dianhydrides that can be used in addition to or in place of the above BPAF, ODPA and 6FDA include aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms and 6 to 50 carbon atoms. and alicyclic tetracarboxylic dianhydrides having 6 to 36 carbon atoms. Among these, aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms are preferred from the viewpoint of yellowness in a high temperature range. The number of carbon atoms as used herein also includes the number of carbon atoms contained in the carboxyl group.

In a preferred embodiment, X ₁ or X ₃ is pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4′-biphenylbis(trimellitic monoester acid anhydride) (TAHQ), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4 ,4′-oxydiphthalic anhydride (ODPA) and cyclopentanonebisspironorbornanetetracarboxylic dianhydride (CPODA).

PMDA, BPDA, DSDA, TAHQ, and CPODA are preferable, and BPDA and TAHQ are more preferable, from the viewpoint of the balance of linear expansion coefficient (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature region. preferable.

In one aspect, the structure of X ₃ in general formula (1) or general formula (2) described later is represented by the following general formula (A-3):

{wherein R ₄ to R ₇ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; ₁ indicates a linking group and * indicates a linking point}
or derived from 4,4′-oxydiphthalic dianhydride (ODPA) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA).

Here, each of R ₆ to R ₉ is not limited as long as it is independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when d to g=0), or halogen. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group, and when d ~ g = 0 may be hydrogen, or halogens include fluorine and the like. Among these, hydrogen is preferable from the viewpoint of yellowness (YI value) in a high temperature range, and fluorine is preferable from the viewpoint of haze (Haze value).

Examples of Z1 include a _single bond, methylene group, ethylene group, ether, ketone, and the like. Among these, a single bond is more preferable from the viewpoint of YI in a high temperature region, and a single bond and an ether are preferable from the viewpoint of residual stress.

Here, d to g are not limited as long as they are integers from 0 to 4, respectively. Among these, an integer of 0 to 2 is preferable from the viewpoint of yellowness (YI value) and residual stress, and 0 is particularly preferable from the viewpoint of yellowness (YI value) in a high temperature region.

In one aspect, the structural unit represented by general formula (A-3) has the following general formula (B-3):

{Wherein, R ₄ to R ₇ , d to g, and Z ₁ are defined in the same manner as in general formula (A-3), and d and e are each independently an integer of 0 to 3. Preferably, f and g are each independently an integer of 0 to 4}
Derived from the acid dianhydride represented by.

As the acid dianhydride represented by the general formula (B-3), more specifically, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 9,9- Bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride (BPF-PA) can be exemplified. BPAF and BPF-PA are preferred from the viewpoint of residual stress.

In general formula (1) or general formula (2) described later, X ₄ is a divalent organic group, preferably at least one of the following general formulas (A-4) to (A-6) A divalent organic group derived from the diamine described in <Embodiment of polyamic acid moiety> can be used. In addition, a plurality of X ₄ present in the polyimide or in the polyimide part may be the same or different, but from the viewpoint of achieving both contradictory performances when made into polyimide, they are different from X ₂ More preferably, the diamine component that constitutes X2 and the diamine component that constitutes _X4 _differ in either diamine composition or diamine species.

In one aspect, the structure of X ₄ in general formula (1) or general formula (2) described later is represented by the following general formula (A-4):

{Wherein, R ₈ to R ₁₁ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; ₂ indicates the linking group and * indicates the linking point}
is represented by

Here, R ₈ to R ₁₁ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms, hydrogen (when h to k=0), or halogen. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group. may be hydrogen, or halogens include fluorine and the like. Among these, hydrogen is preferable from the viewpoint of yellowness (YI value) in a high temperature range, and fluorine is preferable from the viewpoint of haze (Haze value).

Here, h to k are not limited as long as they are integers from 0 to 4, respectively. Among these, an integer of 0 to 2 is preferable from the viewpoint of yellowness (YI value) and residual stress, and 0 is particularly preferable from the viewpoint of yellowness (YI value) in a high temperature region.

Examples of Z2 include _single bond, methylene group, ethylene group, ether, ketone and the like. Among these, a single bond is preferable from the viewpoint of YI in a high temperature region.

In one aspect, the structure of X ₄ in general formula (1) or general formula (2) described later is represented by the following general formula (A-5):

{wherein R ₁₂ and R ₁₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a bond, provided that X ₂ in the general formula (1) is a group derived from 4-amino-3-fluorophenyl-4-aminobenzoate, and X ₃ is 9,9-bis(3 ,4-dicarboxyphenyl)fluorene dianhydride (BPAF), general formula (A-5) excludes 4,4′-diaminodiphenylsulfone or a group derived therefrom}
is represented by

Here, R ₁₂ and R ₁₃ are not limited as long as they are each 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 group, ethyl group and propyl group; halogen-containing groups such as trifluoromethyl group; aryl groups such as phenyl group and naphthyl group; alkoxy groups such as methoxy group and ethoxy group; etc. Among these, a methyl group is preferable from the viewpoint of YI in a high temperature range.

Here, l and m are not limited as long as they are integers from 0 to 4. Among these, an integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.

In one aspect, the structure of X ₄ in general formula (1) or general formula (2) described later is represented by the following general formula (A-6):

{wherein R ₁₄ and R ₁₅ each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and o each independently represent an integer of 0 to 4; * indicates a joint}
is represented by Here, R ₁₄ and R ₁₅ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group; halogen-containing groups such as trifluoromethyl group; aryl groups such as phenyl group and naphthyl group; alkoxy groups such as methoxy group and ethoxy group; etc. Among these, a methyl group and a phenyl group are preferable from the viewpoint of YI in a high temperature range. Here, n and о are not limited as long as they are integers from 0 to 4. Among these, an integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.

In one aspect, the structural unit represented by general formula (A-4) has the following general formula (B-4):

{Wherein, R ₈ to R ₁₁ and h to k are defined in the same manner as in general formula (A-4)}
Derived from the diamine represented by

As the diamine represented by the general formula (B-4), more specifically, 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. can be exemplified, and from the viewpoint of yellowness at high temperature (YI value), BFAF is preferable, cloudy BAFL is preferable from the viewpoint of decreasing the degree (haze value).

Further, in one aspect, the structural unit represented by general formula (A-5) has the following general formula (B-5-1):

Alternatively, the following general formula (B-5-2):

{Wherein, R ₁₂ and R ₁₃ , l and m are defined in the same manner as in general formula (A-5)}
It is derived from a diamine represented by

As diamines represented by general formulas (B-5-1) and (B-5-2), more specifically, 4,4′-diaminodiphenylsulfone (44DAS) and 3,3′-diaminodiphenylsulfone (33 DAS) can be exemplified. More specific examples of other diamines include bis[4-(4-aminophenoxy)phenyl]sulfone and bis[4-(3-aminophenoxy)phenyl]sulfone. 44 DAS is preferable from the viewpoint of yellowness (YI value) at high temperature, and 33 DAS is preferable from the viewpoint of low residual stress.

In one aspect, the structural unit represented by general formula (A-6) has the following general formula (B-6):

{Wherein, R ₁₄ and R ₁₅ , n and о are defined in the same manner as in general formula (A-6)}
It is derived from a diamine represented by

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, and the like. can be exemplified. From the viewpoint of yellowness (YI value) at high temperatures, 44ODA is preferred, and from the viewpoint of low residual stress, 34ODA is preferred.

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 5,000 to 60,000. Especially preferred. When the weight average molecular weight is 1,000 or more, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI is low. When the weight-average molecular weight is 100,000 or less, phase separation is suppressed when a polyamic acid-imide copolymer film is formed, resulting in a low haze (HAZE value). In the present disclosure, the weight average molecular weight is a value obtained as a standard polystyrene conversion value using gel permeation chromatography (hereinafter also referred to as GPC).

Regarding the polyimide or its structural unit, the molar ratio (X ₄ /X ₃ ) between X ₃ and X ₄ contained in the general formula (1) is 0.85 to 2.0, or 1.01 to 2.00. It is preferably 0.95 to 1.5, even more preferably 1.01 to 1.25. When 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 low. When the molar ratio is 2.00 or less, the reactivity with the polyamic acid moiety is improved, and the strength when formed into a film is increased, resulting in excellent mechanical properties such as elongation and breaking strength.

The content of molecules having a molecular weight of less than 1,000 in the polyimide or polyimide portion is preferably less than 5% by mass, and less than 1% by mass, based on the total amount of the polyimide precursor or polyamic acid-imide copolymer. More preferably, less than 0.1% by mass. A polyimide film formed from such a polyimide or a resin composition obtained by using the polyimide part has a low residual stress and a low haze value (haze value) formed on the polyimide film. The content of molecules having a molecular weight of less than 1,000 with respect to the total amount of polyimide or polyimide portion can be calculated from the peak area obtained by GPC measurement using a solution in which the polyimide is dissolved.

The polyimide precursor in one aspect of the present disclosure includes the general formulas (B-1) to (B-2) and (B-4) described above within a range that does not impair elongation, strength, stress, yellowness, etc. In addition to the diamines represented by ~(B-6), or instead of the diamines represented by the general formulas (B-1) ~ (B-2) and (B-4) ~ (B-6), Other diamines can be used. Other diamines include, for example, 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., and one selected from these It is preferred to use the above.

The content of the other diamine in the total diamine is preferably 20 mol % or less, particularly preferably 10 mol % or less. From the viewpoint of heat resistance at high temperatures, it is preferable that _X4 and the diamine constituting it do not contain a silicone _- based diamine, as with X2, and it is more preferable that they are of the type or composition of an aromatic diamine.

(c) <Embodiment of polyamic acid-imide copolymer>
The polyamic acid-imide copolymer of the present invention contains a structural unit M that is a polyamic acid moiety and a structural unit L that includes a structural unit N that is a polyimide moiety, represented by the general formula (1). Embodiments are shown below.

The diamine (X ₂ ) of the polyamic acid portion and the diamine (X ₄ ) of the polyimide portion may have the same composition or diamine species, or may have different compositions or diamine species. The term "same composition" as used herein means that, when the diamine used in the polyamic acid portion is composed of one or more types, the diamines in the polyimide portion have exactly the same composition. On the other hand, the "different composition" here means that when the diamine used in the polyamic acid portion is composed of one or more types, the diamine in the polyimide portion does not have exactly the same composition, but is composed of different diamines or the same This means that the ratios would be different even if more diamines were used.

The role of the polyamic acid moiety in one aspect of the present invention is to have high thermal stability and excellent dimensional stability in a high temperature range, high molecular planarity, and high heat resistance at high temperatures when made into a polyimide. A high skeleton is preferred.

As the acid dianhydride (X ₁ ) of the polyamic acid moiety, pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride ( BPDA), 4,4′-biphenylbis(trimellitic monoester anhydride) (TAHQ), 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF), 3,3 consisting of ',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-oxydiphthalic anhydride (ODPA), and cyclopentanonebisspironorbornanetetracarboxylic dianhydride (CPODA) It is derived from at least one species selected from the group.

PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA are preferable from the viewpoint of the balance of linear expansion coefficient (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature range, and BPDA, TAHQ, and ODPA are more preferred. In addition to the acid dianhydrides shown above, X ₁ may be obtained by using a dicarboxylic acid in addition to the above-mentioned tetracarboxylic dianhydride within a range that does not impair its performance. Other tetracarboxylic dianhydrides may be added, but a skeleton derived from an aromatic tetracarboxylic dianhydride or an aromatic dicarboxylic acid is preferred. The _ratio of other acid dianhydrides and dicarboxylic acids in X1 is preferably 20 mol % or less, more preferably 10 mol % or less.

Examples of the diamine (X ₂ ) of the polyamic acid moiety include (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-amino It is preferably at least one selected from the group consisting of phenyl-3-methyl-4-aminobenzoate and (2-phenyl-4-aminophenyl)-4-aminobenzoate (ph-APAB), and the linear expansion coefficient APAB, 2F-APAB, 3F-APAB, and Ph-APAB are preferred, and APAB is more preferred, from the viewpoint of balance of (CTE), chemical resistance, glass transition temperature (Tg), and yellowness in a high temperature range. As X ₂ , in addition to the acid dianhydrides shown above, other diamines may be added to the extent that their performance is not impaired, but they are aromatic diamines that do not contain a cyclohexane ring or a cyclopentane ring. The ratio of other diamines in X ₂ is preferably 20 mol% or less, more preferably ₁₀ mol% or less. Although it is preferable not to contain the structure shown in , this is not the case unless the composition is exactly the same.

The role of the imide portion in one aspect of the present invention is to have high thermal stability in a high temperature range, excellent optical properties, and high solubility in solvents, and excellent optical properties and high solubility in solvents. or a skeleton capable of imparting bending resistance when formed into a film is preferred.

As the acid dianhydride (X ₃ ) of the polyimide portion, a tetravalent organic group derived from a tetracarboxylic dianhydride can be used as described in (b) <Embodiment of polyimide portion>. In addition, a plurality of X ₃ present in the polyimide precursor or the polyamic acid-imide copolymer may be the same or different from each other, and may be the same or different from X ₁ . . X ₃ preferably includes a structure derived from BPAF from the viewpoint of excellent yellowness (YI value) and haze (Haze value) in a high-temperature region, and a structure derived from ODPA from the viewpoint of residual stress. preferable. When using a skeleton derived from BPAF, a skeleton selected from PMDA, BPDA, DSDA, TAHQ, ODPA, and CPODA can be used at the same time for the purpose of improving thermal stability in a high temperature range. Among them, it is more preferable to contain a skeleton selected from BPDA, TAHQ, and ODPA. The proportion of _BPAF in X3 is preferably 40 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, and may be 100 mol%. From the viewpoint of excellent bending resistance when made into a polyimide film, the higher the proportion of BPAF, the better.

As the diamine of the imide portion, a divalent organic group derived from diamine can be used as described in (b) <Embodiment of polyimide portion>. In addition, a plurality of X ₄ present in the polyimide precursor or the polyamic acid-imide copolymer may be the same or different from each other, and may be the same or different from X ₂ . but must not be exactly the same. X ₄ is preferably at least one selected from the group selected from 44BAFL, 33BAFL, BFAF, BAOFL, BAHF, 33DAS, and 44DAS, and has a coefficient of linear expansion (CTE), chemical resistance, glass transition temperature 44BAFL, 33BAFL, BFAF, BAOFL, 33DAS, 44DAS, 44ODA, and 34ODA are more preferable from the viewpoint of balance of (Tg) and yellowness in a high temperature range.

The polyamic acid-imide copolymer contains a polyamic acid portion composed of X ₁ and X ₂ and a polyimide portion composed of X ₃ and X ₄ , and the molar ratio of the polyamic acid structural unit to the polyimide structural unit The upper limit of (number of moles of structural unit N: number of moles of structural unit M) may be 95:5, 90:10, 85:15, or 80:20. Haze value), the ratio is preferably 95:5, and yellowness index (YI value) is more preferably 80:20. The lower limit of the molar ratio of the constituent units of the polyamic acid and the constituent units of the polyimide (number of moles of structural unit N: number of moles of structural unit M) may be 30: 70, 40: 60, or 50: 50. It may be 60:40, but it is preferably 40:60 or 60:40 from the viewpoint of coexistence of residual stress and yellowness (YI value).

The weight average molecular weight (Mw) of the polyamic acid-imide copolymer (structural unit L) is preferably 2,639 or more, more preferably 2,639 to 300,000 or 10,000 to 300,000, and 20,000. ~250,000 is more preferred, and 40,000 to 200,000 is particularly preferred. When the weight average molecular weight is 2,639 or more, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI is low. When the weight average molecular weight is 300,000 or less, the viscosity and concentration of the polyamic acid-imide copolymer varnish are well-balanced, the workability is good, and film unevenness during coating is reduced. Further, when the Mw of the polyamic acid-imide copolymer is 170,000 or more, transparency, haze, heat resistance and coefficient of linear expansion tend to be excellent, and Mw of 220,000 or more is more preferable. This tendency is remarkable when X ₂ in general formula (1) has the structure represented by general formula (A-1) above. The weight average molecular weight (Mw) of the polyamic acid-imide copolymer is preferably 170,000 or more, more preferably 220,000 or more, from the viewpoint of IR (infrared) cure defect evaluation and degassing evaluation.
In the present disclosure, the weight average molecular weight is a value obtained as a standard polystyrene conversion value using gel permeation chromatography (hereinafter also referred to as GPC)

<(B) Embodiment of polyamic acid>
For the polyamic acid according to the fourth embodiment, which includes a structural unit represented by the general formula (3) and has a structure represented by the general formula (A-1) as X ₂ , the general formula (3 ), X ₁ is a tetravalent organic group, and a plurality of X ₁ present in the polyimide precursor may be the same or different. X ₁ is exemplified by a tetravalent organic group derived from a tetracarboxylic dianhydride, and the tetracarboxylic dianhydride is the tetracarboxylic dianhydride exemplified for the (A) polyamic acid-imide copolymer. Same as anhydride.

In one aspect of the polyamic acid, in the general formula (3), X ₂ is a divalent organic group, and multiple X ₂ present in the polyimide precursor may be the same or different. . Examples of X2 include _divalent organic groups derived from diamines, and the diamines are the same as the diamines exemplified for the (A) polyamic acid-imide copolymer.

The structural unit represented by the general formula (A-1) for the polyamic acid is the same as the general formula (A-1) exemplified for the above (A) polyamic acid-imide copolymer.

The weight average molecular weight (Mw) of the polyamic acid according to the fourth embodiment is preferably 3,000 or more, more preferably 10,000 to 300,000, still more preferably 20,000 to 250,000, and 40,000 ~200,000 is particularly preferred. When the weight average molecular weight is 3,000 or more, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI is low. When the weight-average molecular weight is 300,000 or less, the viscosity and concentration of the polyamic acid-imide copolymer varnish are well-balanced, workability is good, and film unevenness during coating is reduced.

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

(diamine)
Diamines containing a P ₁ group in general formulas (I) and (II) include 4,4'-diaminodiphenylsulfone (4,4'-DAS), 3,4'-diaminodiphenylsulfone (3,4' -DAS), 3,3′-diaminodiphenylsulfone (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 and 1,4-bis(3-aminopropyldimethylsilyl)benzene 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 and the like. These diamines may be used singly or in combination of two or more.

In general formulas (I) and (II) above, P ₁ preferably contains a structural unit derived from at least one diamine represented by general formulas (3) to (12) below.

The content of the structure derived from the diamine compound in all diamines (excluding compounds in which L1 and L2 are amino groups in general formula (13) described later) is 20 mol% or more, 40 mol% or more, and 50 mol. % or more, 70 mol % or more, 90 mol % or more, or 95 mol % or more.

(Acid dianhydride)
In general formulas (I) and (II), acid dianhydrides containing P ₂ groups include pyromellitic dianhydride (PMDA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride. (BPDA), 2,2′,3,3′-biphenyltetracarboxylic dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 5-(2,5-dioxo Tetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2dicarboxylic anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic acid acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, methylene-4,4'-diphthal acid dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2-propylidene-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 (ODPA), p-phenylene bis(trimellitate anhydride), thio-4,4'-diphthalic dianhydride, sulfonyl-4 ,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1, 4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, 1,4-bis [ 2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 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-dicarboxy phenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyl Disiloxane dianhydride, 2,3,6,7-naph Talentetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetra carboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-bis(3,4-di Carboxyphenyl)fluorene dianhydride (BPAF), bicyclohexyl-3,3′,4,4′-tetracarboxylic dianhydride (CpODA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), and the like. These acid dianhydrides may be used singly or in combination of two or more.

<Silicon-containing compound>
The polyamic acid, polyamic acid-imide copolymer, polyimide copolymer, polyimide precursor or polyimide resin described above has the following general formula (14):

{Wherein, each of R ₁ and R ₂ , if plural, is independently 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 from 1 to 200}
can contain a structure represented by

When the structure of general formula (14) is included, the Rth and residual stress of the obtained polyimide film are improved, which is preferable.

In order for the resin to have the structure of the general formula (14), X ₁ to X ₄ in the general formulas (1) and (2), or P ₁ or P ₂ in the general formulas (I) and (II) , the following general formula (13):

{wherein R ₁ is each independently a single bond or a divalent organic group having 1 to 10 carbon atoms, and R ₂ and R ₃ are each independently a monovalent organic group having 1 to 10 carbon atoms; at least one is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, R ₄ and R ₅ are each independently a monovalent organic group having 1 to 10 carbon atoms, At least one is a monovalent aromatic group having 6 to 10 carbon atoms, R ₆ and R ₇ are each independently a monovalent organic group having 1 to 10 carbon atoms, and L ₁ and L ₂ are , each independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group, i is an integer of 1 to 200, j and k are each independently an integer of 0 to 200, 0≦j/(i+j+k)≦0.50, and the functional group equivalent is 800 or more. }
It can contain structural units derived from the silicon-containing compound represented by.

In the resin composition, the silicon-containing compound represented by the general formula (13) is:
20 mol% or less when the diamine is 100 mol%; or
When the acid dianhydride is 100 mol %, it is 20 mol % or less. The silicon-containing compound within the above range is preferable from the viewpoint of filterability of the resulting polyimide precursor or polyimide resin composition. From the viewpoint of further improving filterability, 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. The silicon-containing compound can exceed 0 mol % when the total diamine or total acid dianhydride in the resin composition is taken as 100 mol %.

Each R ₁ in formula (13) 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 linear, cyclic or branched, and may be saturated or unsaturated. Examples of divalent aliphatic hydrocarbon groups having 1 to 10 carbon atoms include methylene group, ethylene group, n-propylene group, i-propylene group, n-butylene group, s-butylene group, t-butylene group, Linear or branched alkylene groups such as n-pentylene group, neopentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group; cyclopropylene group, cyclobutylene group, Cycloalkylene groups such as a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, and a cyclooctylene group can be mentioned. The divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of ethylene group, n-propylene group and i-propylene group.

R ₂ and R ₃ in formula (13) are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one is a monovalent aliphatic hydrocarbon group having 1 to 5 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, monovalent organic groups having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, t-butyl group and n-pentyl. linear or branched alkyl groups such as group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl cycloalkyl groups such as groups, cycloheptyl groups and cyclooctyl groups; and aromatic groups such as phenyl groups, tolyl groups, xylyl groups, α-naphthyl groups and β-naphthyl groups.

A monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms may be linear, cyclic or branched, and may be saturated or unsaturated. For example, monovalent aliphatic hydrocarbon groups having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, t-butyl group, linear or branched alkyl groups such as n-pentyl group and neopentyl group; and cycloalkyl groups such as cyclopropyl group, cyclobutyl group and cyclopentyl group. The monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms is preferably at least one selected from the group consisting of methyl group, ethyl group and n-propyl group.

R ₄ and R ₅ in formula (13) are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one 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, monovalent organic groups having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, t-butyl group and n-pentyl. linear or branched alkyl groups such as group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl cycloalkyl groups such as groups, cycloheptyl groups and cyclooctyl groups; and aromatic groups such as phenyl groups, tolyl groups, xylyl groups, α-naphthyl groups and β-naphthyl groups. Examples of monovalent aromatic groups having 6 to 10 carbon atoms include phenyl group, tolyl group, xylyl group, α-naphthyl group, β-naphthyl group and the like. Preferably.

R ₆ and R ₇ in formula (13) are each independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is an organic group having an unsaturated aliphatic hydrocarbon group. preferable. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic or branched. Examples of monovalent organic groups having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, s-butyl group, t-butyl group and n-pentyl. linear or branched alkyl groups such as group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl cycloalkyl groups such as groups, cycloheptyl groups and cyclooctyl groups; and aromatic groups such as phenyl groups, tolyl groups, xylyl groups, α-naphthyl groups and β-naphthyl groups. The monovalent organic group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of methyl group, ethyl group and phenyl group.
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 linear, cyclic or branched. Examples of unsaturated aliphatic hydrocarbon groups having 3 to 10 carbon atoms include vinyl group, allyl group, 1-propenyl group, 3-butenyl group, 2-butenyl group, pentenyl group, cyclopentenyl group, hexenyl group, cyclo hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group and the like. The unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms is preferably at least one selected from the group consisting of vinyl group, allyl group and 3-butenyl group.

Some or all of the hydrogen atoms of R ₁ to R ₇ in formula (13) may be substituted with substituents such as halogen atoms such as F, Cl and Br, or may be unsubstituted.

L ₁ and L ₂ in formula (13) each independently represent a monovalent organic group containing an acid anhydride structure (also referred to as an acid anhydride group), an amino group, an isocyanate group, a carboxyl group, an alkoxycarbonyl group, a carbonyl halide group, a hydroxy group, an epoxy group, or a mercapto group;
As the monovalent organic group containing an acid anhydride structure, for example, the following formula:

{In the above formula, "*" represents a bond. } and a 2,5-dioxotetrahydrofuran-3-yl group.

Among these, an amino group and an acid anhydride group are preferred, and an amino group is more preferred from the viewpoint of the viscosity stability of the resin composition.

The alkoxyl group in the alkoxycarbonyl group may be an alkoxyl group having 1 to 6 carbon atoms, such as methoxyl group, ethoxyl group, n-propoxyl group, i-propoxyl group, n-butoxyl group, i-butoxyl group. , t-butoxyl group and the like.

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.

The functional group equivalent of the silicon-containing compound represented by formula (13) is preferably 800 or more, more preferably 1000 or more, even more preferably 1500 or more, from the viewpoint of filterability of the resin composition. On the other hand, when the functional group equivalent is 500 or less, filterability may deteriorate. Here, the functional group equivalent is the molecular weight of the silicon-containing compound per 1 mol of functional group (unit: g/mol). The functional group equivalent can be measured by a known method according to existing standards and the like. Moreover, 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 small, which is preferable. The reason for this is thought to be that when the functional group equivalent is a specific value or more, the number of silicone domains increases and the stress is relaxed.

i in formula (13) is an integer of 1 to 200, preferably an integer of 2 to 100, more preferably an integer of 4 to 80, and still more preferably an integer of 8 to 40. j and k are each independently an integer of 0 to 200, j may 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 It is preferably an integer of 0-50.

It is preferable that the resin in the resin composition has a structure derived from formula (13), since the residual stress of the polyimide film measured in a nitrogen atmosphere is good (small). The reason for measuring in a nitrogen atmosphere is that in the display process, when forming an inorganic film such as SiO, SiN, etc. on a polyimide film, it may be exposed to a nitrogen atmosphere, and the residual stress under the nitrogen atmosphere is small. This is because it is required.

L ₁ and L ₂ in general formula (13) are each independently preferably an amino group from the viewpoint of the type of monomer, the cost, and the molecular weight of the resulting polyimide precursor. That is, the silicon-containing compound of formula (13) is preferably a silicon-containing diamine. Silicon-containing diamines include, for example, the following general formula (15):

_{ wherein P ₅ _each independently represents a _divalent _hydrocarbon group and may be the same or different; Similarly, l represents an integer of 1-200. }
Diamino(poly)siloxane represented by is preferred.

Preferable structures of _P3 and _P4 in the general formula (15) include a methyl group, an ethyl group, a propyl group, a butyl group and a phenyl group. Among these, a methyl group is preferred.

l in the general formula (15) is an integer of 1 to 200, and an integer of 3 to 200 from the viewpoint of the heat resistance of the polyimide obtained using the silicon-containing diamine represented by the formula (15). is preferred.

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

The content (copolymerization ratio) of the silicon-containing compound represented by the general formula (13) is 0.5% by mass or more and 20% by mass when the total monomer mass (polyimide precursor/total mass of polyimide) is 100% by mass. % or less is preferable.
When the content of the silicon-containing compound is 0.5% by mass or more, the residual stress generated between the substrate and the support 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), and is preferable from the viewpoint of realizing high total light transmittance and high glass transition temperature.

As described above, the silicon-containing compound used as a polyimide precursor/polyimide monomer may be synthesized using the common general knowledge at the time of filing, or may be a commercially available product. Commercially available products include amine-modified methylphenyl silicone oil at both ends (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-1660B-3 (functional group equivalent weight: 2200), X22-9409 (functional group equivalent weight: 670)), acid anhydride-modified methylphenyl at both ends. Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-168-P5-B (functional group equivalent weight 2100)), both ends epoxy-modified methylphenyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-2000 (functional group equivalent weight 620)), both ends Amino-modified dimethyl silicone (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), Toray Dow Corning: BY16-853U (functional group equivalent 450), JNC: Silaplane FM3311 (number average molecular weight 1000)), epoxy-modified dimethyl silicone at both ends (Shin-Etsu Chemical: X-22-163A (functional group equivalent 1750 ), both ends alicyclic epoxy-modified dimethyl silicone (manufactured by Shin-Etsu Chemical Co.: X-22-169B (functional group equivalent weight 1700)), both ends hydroxy group-modified dimethyl silicone (manufactured by Shin-Etsu Chemical Co.: KF-6000), both ends Mercapto-modified dimethyl silicone (manufactured by Shin-Etsu Chemical Co., Ltd.: X-22-167B (functional group equivalent: 1700)), acid anhydride-modified dimethyl silicone on both ends (manufactured by Shin-Etsu Chemical: X-22-168A (functional group equivalent: 1000)), etc. Among these, from the viewpoint of price, improvement in chemical resistance, and improvement in Tg, both terminal amine-modified dimethylsilicone oils are preferred.

(d) organic solvent (d) organic solvent is capable of dissolving the above-mentioned (a) polyamic acid, (b) polyimide, (c) polyamic acid-imide copolymer and optionally used other components. There is no particular limit if any. Specific examples of such (d) organic solvents include aprotic solvents, phenolic solvents, ether and glycol solvents, and the like.

The aprotic solvent preferably has polarity and/or preferably has a boiling point of 250° C. to 350° C., from the viewpoint of improving the in-plane uniformity of the film thickness and decreasing the YI value. An aprotic polar substance having a boiling point of 250° C. to 350° C., which will be described later, may be used.

Aprotic solvents include, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, and an amide solvent of the following general formula:

{Wherein, R ₁₂ = 3-methoxy-N,N-dimethylpropanamide (manufactured by KJ Chemicals, trade name: Equamid M100) represented by a methyl group, and R ₁₂ = represented by an n-butyl group 3-butoxy-N,N-dimethylpropanamide (manufactured by KJ Chemicals, trade name: Equamid B100)}; lactone solvents such as γ-butyrolactone and γ-valerolactone; hexamethylphosphoricamide, hexamethylphosphinetriamide Phosphorus-containing amide solvents such as; dimethylsulfone, dimethylsulfoxide, sulfur-containing solvents or sulfone structure-containing compounds such as sulfolane; ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; Ester solvents such as (2-methoxy-1-methylethyl) and the like are included.

Among these, aprotic polar solvents are N-methylpyrrolidone, N-ethylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 3-methoxy-N,N-dimethylpropanamide, γ-butyrolactone , γ-valerolactone, and sulfolane, and more preferably sulfolane.

Phenolic solvents such as 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, etc.; ether and glycol solvents such as 1,2-dimethoxyethane , bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, etc. mentioned.

(d) The organic solvent preferably contains at least one selected from NMP, GBL, DMF, and DMAc from the viewpoint of solubility of polyamic acid, polyimide, and polyamic acid-imide copolymer.

[Other ingredients]
In addition to the above components (a), (b), (c) and (d), the resin composition contains (e) an imidization catalyst, an aprotic polar substance, a surfactant, an alkoxysilane compound, etc. Further, it may be contained.

((e) imidization catalyst)
In the step of obtaining a polyimide resin film from a resin composition by imidization, an imidization catalyst can be added to the resin composition.

The resin composition can contain 0.01 to 0.5 mol % of the imidization catalyst per 1 mol of the repeating unit of the (c) polyamic acid-imide copolymer. When the content of the imidization catalyst is 0.01 mol % or more per 1 mol of the repeating unit of the polyamic acid-imide copolymer, the yellowness (YI value) of the film can be suppressed. From the viewpoint of the storage stability of the resin composition, the content of the imidization catalyst is preferably 0.5 mol % or less. The content of the imidization catalyst is more preferably 0.015 to 0.5 mol%, more preferably 0.02 to 0.5 mol%, relative to 1 mol of the repeating unit of the polyamic acid-imide copolymer. is more preferred, and 0.02 to 0.15 mol % is particularly preferred.

(e) The content of the imidization catalyst is 5 parts by mass or more with respect to 100 parts by mass of the polyamic acid-imide copolymer or polyamic acid described above, from the viewpoint of the effects of the present invention. is preferred, and 10 parts by mass or more is more preferred.

Examples of imidization catalysts include, but are not limited to, pyridine, triethylamine, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, N-tert-butoxycarbonyl. imidazole (N-Boc-imidazole) and the like. Further, as the imidization catalyst, from the viewpoint of the effects of the present invention, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, benzimidazole, or N-tert-butoxy Imidazole compounds such as carbonylimidazole (N-Boc-imidazole) are preferred, 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, imidazole and the like are more preferred, 1,2-dimethylimidazole, N-tert- Butoxycarbonylimidazole (N-Boc-imidazole), 1-methylimidazole and the like are more preferred, and imidazole compounds containing N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and/or 1-methylimidazole are even more preferred, N-Boc-imidazole is particularly preferred from the viewpoint of storage stability, and 1-methylimidazole is particularly preferred from the viewpoint of yellowness (YI value) at high temperatures.

In addition, although the imidization catalyst is not particularly limited, nitrogen-containing compounds can be mentioned, and specific examples include imidazole compounds, pyridine compounds, tertiary amine compounds, and the like.

Examples of imidazole compounds 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 is mentioned.

Pyridine compounds include 4-dimethylaminopyridine, 2,2'-bipyridyl, nicotinic acid, isoquinoline, pyridine, and 2-methylpyridine.

Tertiary amine compounds include 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and triethylamine.

These compounds can also be used in combination of two or more.

Among these, from the viewpoint of IR (infrared) cure defect evaluation and outgassing evaluation described later, 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, pyridine compounds such as 4-dimethylaminopyridine, 2,2'-bipyridyl, 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, and 1-methylimidazole and N-tert-butoxycarbonylimidazole (N-Boc-imidazole) are more preferred.

The content of the imidization catalyst is preferably 1 part by mass or more, preferably 5 parts by mass or more, relative to 100 parts by mass of the polyamic acid-imide copolymer or polyamic acid, from the viewpoint of IR (infrared) cure defect evaluation and degassing evaluation. is more preferable, and 10 parts by mass or more is particularly preferable.

The IR (infrared) cure defect evaluation to be described later is based on the following a. can be improved by adopting any one or more of ~c;
Using an imidization catalyst as an additive b. Using an aprotic polar substance with a boiling point of 250-350 as an additive c. Increasing the molecular weight of polyamic acid-imide copolymer/polyamic acid thing.

Although the mechanism of the good effect is not clear, it is thought that there is a correlation with promotion of imidization. That is, it is thought that the cause of IR cure defects is correlated with the formation of oligomers and their decomposition by infrared rays. b. This is probably because the use of the promotes imidization and suppresses the formation of oligomers. Moreover, c. Also, it is considered that if the molecular weight is increased, the formation of oligomers is suppressed as a result.

Further, the degassing evaluation to be described later is based on the following a. can be improved by adopting any one or more of ~c;
Using an imidization catalyst as an additive b. Using an aprotic polar substance with a boiling point of 250-350 as an additive c. Increasing the molecular weight of polyamic acid-imide copolymer/polyamic acid thing.

Although the mechanism of the good effect is not clear, it is thought that there is a correlation with promotion of imidization. That is, the cause of degassing is thought to be correlated with the fact that low-molecular-weight components and oligomers remain in the polyimide film after curing. b. This is probably because the use of promotes imidization and suppresses the formation of low-molecular-weight components and oligomers. Moreover, c. Also, if the molecular weight is increased, residual low-molecular-weight components/oligomers are thought to be suppressed.

(f) Aprotic Polar Substance with a Boiling Point of 250 to 350°C The resin composition according to one aspect of the present disclosure contains an aprotic polar substance with a boiling point of 250 to 350°C. _Aprotic polar substances with boiling points of 250° C. to 350° C. that can be preferably used include ketones, esters, carbonates, It is a compound having at least one chemical structure (functional group) selected from amide, nitrile, sulfoxide, and sulfone.

Specific examples of compounds that are preferably used include, for example, compounds having a ketone structure with a boiling point of 250° C. to 350° C., such as benzophenone, methylbenzophenone, dimethylbenzophenone, and dodecanedione.
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, isoamyl benzoate, dibutyl maleate, cinnamon. Ethyl acid, diethylene glycol diacetate, diethyl adipate, etc.
As a compound having a carbonate structure with a boiling point of 250° C. to 350° C., diphenyl carbonate, etc.
As compounds having an amide structure with a boiling point of 250° C. to 350° C., benzamide, N,N-dimethylbenzamide, adipamide, etc.
As a compound having a nitrile structure with a boiling point of 250° C. to 350° C., adiponitrile etc.
As compounds having a sulfoxide structure with a boiling point of 250° C. to 350° C., dibutyl sulfoxide, diphenyl sulfoxide, etc.
Examples of compounds having a sulfone structure with a boiling point of 250° C. to 350° C. include sulfolane, 3-methylsulfolane, dibutylsulfone, and benzenesulfonamide.
Among these compounds, sulfolane and 3-methylsulfolane are more preferably used.

An aprotic polar substance with a boiling point of 250 ° C. to 350 ° C. is added to a polyamic acid-imide copolymer or a polyamide precursor alone or in combination with a solvent, and then coated and cured (heated) to cause IR cure defects. Evaluation and degassing evaluation can be improved. The effect is particularly remarkable when adding 5 wt % or more when (mass of solvent + mass of aprotic polar substance) is 100 wt %. The upper limit of the amount of the aprotic polar substance to be added is 100 wt% when (the mass of the solvent + the mass of the aprotic polar substance) is 100 wt%, and the more preferable addition amount is 30 wt% or less.

(Aprotic polar substance with a boiling point of 250°C to 350°C)
The resin composition preferably contains an aprotic polar substance with a boiling point of 250°C to 350°C.
_Aprotic polar substances with boiling points of 250° C. to 350° C. that can be preferably used include ketones, esters, carbonates, It is a compound having at least one chemical structure (functional group) selected from amide, nitrile, sulfoxide and sulfone. The aprotic polar substance may overlap with the aprotic solvent described above as long as its boiling point is between 250°C and 350°C.

An aprotic polar substance having a boiling point of 250 ° C. to 350 ° C. is added to a polyamide precursor, or a resin having a polyamide precursor and a polyimide structure, or a solvent-soluble polyimide, alone or in combination with a solvent to coat and cure ( heating), the in-plane film thickness uniformity of the cured film can be improved and the YI can be lowered as compared with the case where the cured film is not added. The effect is particularly remarkable when adding 5 wt % or more when (mass of solvent + mass of aprotic polar substance) is 100 wt %.

Aprotic polar substances with a boiling point of 250°C to 350°C remain in the film even at temperatures of 250°C or higher in the polyimide curing process (heating to about 400°C), and play a role as a plasticizer at high temperatures. play. For this reason, in the temperature range of 250° C. or higher in the curing process, the resin becomes soft and fluid, which is thought to improve the in-plane uniformity of the film thickness and decrease the YI. On the other hand, if the amount of the aprotic polar substance 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 film after curing. In the flexible display manufacturing process, an inorganic film such as silicon nitride is formed on the cured film by CVD, etc., and then a layer of amorphous silicon or low-temperature polysilicon is formed on it, and the same temperature as the curing temperature is applied again. (re-annealing step). If an aprotic polar substance with a boiling point of 250° C. to 350° C. remains in the film after curing, it will volatilize during re-annealing, causing blisters in the inorganic film formed on the film. In order to prevent this, it is necessary to suppress the residual amount of the substance in the film to 1000 ppm or less.

Therefore, the upper limit of the amount of the aprotic polar substance added is, in the case of a polyimide precursor or a resin having a polyimide precursor skeleton and a polyimide skeleton, (mass of solvent + mass of aprotic polar substance) to 100 wt%. is 100 wt%.
In the case of a solvent-soluble polyimide containing a solvent in addition to the polyimide precursor or the resin having the polyimide precursor skeleton and the polyimide skeleton, (the mass of the solvent + the mass of the aprotic polar substance) was set to 100 wt%. is 50 wt%.
In the case of a polyimide precursor, a polyimide precursor skeleton and a resin having a polyimide skeleton, and in the case of a solvent-soluble polyimide, the addition amount is more preferably 30 wt % or less.

Among the aprotic polar substances, sulfolane and 3-methylsulfolane are excellent in improving the in-plane uniformity of the cured film and reducing YI. Similar effects are exhibited with other substances, but the effects are remarkable when sulfolane and 3-methylsulfolane are used.
When the boiling point of the aprotic polar substance is less than 250° C., the effects of improving the in-plane uniformity of the cured film and reducing the YI are not exhibited. If the boiling point exceeds 350° C., the effect is exhibited, but more than 1000 ppm remains in the cured film, which is not preferable from the viewpoint of degassing.

(Surfactant)
By adding a surfactant to the resin composition, the coatability of the resin composition can be improved. Specifically, it is possible to prevent the occurrence of streaks in the coating film.

Examples of such surfactants include silicone-based surfactants, fluorine-based surfactants, nonionic surfactants other than these, and the like. 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 name, manufactured by Dow Corning Toray Silicone Co., Ltd.); SILWET L-77, L-7001, FZ-2105, FZ -2120, FZ-2154, FZ-2164, FZ-2166, L-7604 (trade name, manufactured by Nihon Unicar); 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, manufactured by BYK-Chemie Japan); Granol (trade name, manufactured by Kyoeisha Chemical Co., Ltd.) and the like. Examples of fluorine-based surfactants include Megafac F171, F173, R-08 (manufactured by Dainippon Ink and Chemicals, Inc., trade names); Florard FC4430, FC4432 (Sumitomo 3M Co., Ltd., trade names). . Nonionic surfactants other than these include, for example, polyoxyethylene uralyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether and the like.

Among these surfactants, silicone-based surfactants and fluorine-based surfactants are preferable from the viewpoint of coatability (streak suppression) of the resin composition. A silicone-based surfactant is preferable from the viewpoint of reducing the influence on the rate. 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 with respect to 100 parts by mass of the polyimide precursor in the resin composition.

(alkoxysilane compound)
When the polyimide film obtained from the resin composition is used for a flexible substrate or the like, from the viewpoint of obtaining good adhesion between the support and the polyimide film in the production process, the resin composition contains, with respect to 100 parts by mass of the polyimide precursor, An alkoxysilane compound can be contained in an amount of 0.01 to 20 parts by mass. When the content of the alkoxysilane compound is 0.01 parts by mass or more relative to 100 parts by mass of the polyimide precursor, good adhesion can be obtained between the support and the polyimide film. Moreover, it is preferable that the content of the alkoxysilane compound is 20 parts by mass or less from the viewpoint of the storage stability of the resin composition. 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 still more preferably 0.1 to 8 parts by mass with respect to 100 parts by mass of the polyimide precursor. be. By using an alkoxysilane compound, in addition to the above-mentioned improvement in adhesion, the coatability of the resin composition is improved (streak unevenness suppression), and the influence of the oxygen concentration during curing on the YI value of the polyimide film is reduced. You can also

Examples of alkoxysilane compounds include 3-ureidopropyltriethoxysilane, bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-Aminopropyltripropoxysilane, γ-Aminopropyltributoxysilane, γ-Aminoethyltriethoxysilane, γ-Aminoethyltripropoxysilane, γ-Aminoethyltributoxysilane, γ-Aminobutyltriethoxysilane, γ- Aminobutyltrimethoxysilane, γ-Aminobutyltripropoxysilane, γ-Aminobutyltributoxysilane, Phenylsilanetriol, Trimethoxyphenylsilane, Trimethoxy(p-tolyl)silane, Diphenylsilanediol, Dimethoxydiphenylsilane, Diethoxydiphenyl silane, dimethoxydi-p-tolylsilane, triphenylsilanol, and the following structure:

and alkoxysilane compounds represented by each of the above. An alkoxysilane compound may be used individually by 1 type, or may be used in combination of 2 or more types.

[Method for producing polyamic acid-imide copolymer]
The polyamic acid, polyimide, and polyamic acid-imide copolymer of the present invention can be synthesized by a production method including the following steps. For example, a method for producing a polyamic acid-imide copolymer has the following steps 1 to 3:
Step 1: A step of reacting the tetracarboxylic dianhydride component (X ₃ ) of the polyamic acid moiety constituting the general formula (1) with the diamine component (X ₄ ) to obtain a solvent-soluble polyimide solution;
Step 2: A step of dissolving the diamine (X ₂ ) of the polyamic acid moiety in the general formula (1) in the polyimide obtained in Step 1; and Step 3: For the solution obtained in Step 2, the A step of reacting the tetracarboxylic dianhydride component (X ₁ ) of the polyamic acid moiety constituting the general formula (1) to obtain a polyamic acid-imide copolymer.

First, specific embodiments will be described in order from step 1. Step 1 is a step of synthesizing the polyimide portion in the general formula (1). It can be synthesized by subjecting a diamine (eg, 44BAFL) of the polyimide moiety in the general formula (1) and a tetracarboxylic dianhydride (eg, BPAF) to a polycondensation reaction. This reaction is preferably carried out in a solvent capable of dissolving the monomer and the polyimide to be purified, using a reaction vessel from which water generated during imidization is removed. Specifically, for example, a predetermined 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 predetermined amount of BPAF and toluene as an azeotropic solvent of water are added. is added, heated to 180° C., and stirred. Water generated during heating at 180° C. and toluene as an azeotropic solvent are preferably discharged out of the container as appropriate.

When synthesizing the polyimide precursor, the ratio (molar ratio) of the tetracarboxylic dianhydride component and the diamine component is the thermal linear expansion coefficient, residual stress, elongation, and yellowness of the resulting resin film (hereinafter, YI from the viewpoint of controlling tetracarboxylic dianhydride: diamine = 100: 85 to 100: 200 (diamine 0.85 to 2.0 to 1 mol part of tetracarboxylic dianhydride). 00 mol parts), and more preferably 100:101 to 100:125 (1.01 to 1.25 mol parts of diamine to 1 mol part of acid dianhydride). By setting it as said range, reaction with a polyamic acid becomes easy and it is preferable at the point of a haze degree (Haze value) falling.

From the viewpoint of achieving both imidization and water removal, the reaction temperature is preferably 140°C or higher, more preferably 160°C. The reaction temperature is preferably 200° C. or lower, more preferably 190° C. or lower, from the viewpoint of suppressing coloration due to decomposition of the solvent and reaction with the monomer, and the temperature should be quickly reduced to 100° C. or lower after the completion of the reaction. is preferred.

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

Next, step 2 will be described. Step 2 is a step of dissolving the diamine (X ₂ ) of the polyamic acid moiety in the general formula (1) in the polyimide obtained in the step 1 above. After synthesizing polyimide in step 1, predetermined amounts of diamine (for example, APAB) and NMP are added and thoroughly stirred 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 a desired range, the tetracarboxylic dianhydride of the polyimide part component (X ₃ ) derived from the product: component (X ₂ and X ₄ ) derived from the diamine component of the polyimide part and the polyamic acid part = 100: 150 to 100: 3000 (per 1 mol part of tetracarboxylic dianhydride 1.50 to 30 mol parts of diamine), and the range of 100:225 to 100:2000 (2.25 to 20 mol parts of diamine per 1 mol part of tetracarboxylic dianhydride) and More preferably, the molar ratio (diamine/tetracarboxylic dianhydride) is 2.25-20. By setting the above range, the reaction uniformity when reacting the tetracarboxylic dianhydride in step 3 is improved, the molecular weight distribution is close to 2.00, and the proportion of oligomers having a molecular weight of 1,000 or less is low Polyamic acid - An imide copolymer is obtained, and the thermal stability in a high-temperature region when made into a film is improved.

The temperature for dissolving the diamine is preferably 40°C or higher, more preferably 60°C or higher, from the viewpoint of increasing 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, the temperature is preferably 120° C. or lower, more preferably 100° C. or lower.

Next, we will discuss process 3. In step 3, a tetracarboxylic dianhydride of the polyamic acid moiety in the general formula (1) is added to the solution in which the polyimide and diamine in step 2 are dissolved, and polycondensation reaction is performed to obtain polyamic acid-imide. Copolymers can be synthesized.

As a method for producing a polyamic acid-imide copolymer including steps different from the above steps 1 to 3, the production method described in International Publication No. 2020/138360 is known. Specifically, the imidization step of step ₁ includes a step of simultaneously _imidizing the diamine compounds corresponding to X2 and _X4 , and a common diamine compound is used for X2 and _X4 . I can.

However, according to the present inventors, when the same production method as in WO 2020/138360 is used, that is, during imide synthesis in step 1, general formula (B-1) or (B-2 ) was used as a raw material, the molecular weight was not sufficiently increased, and a polyamic acid-imide copolymer that could be evaluated could not be obtained. This is because the diamines represented by the general formulas (B-1) and (B-2) have high reactivity and poor thermal stability in high-temperature solvents, and the amine is in excess of the acid at high temperatures (about 180 ° C.), the diamine reacts with a solvent or oxygen and is deactivated, and the polyamic acid-imide copolymer cannot be sufficiently increased in the next step. it is conceivable that.

Specifically, a reproduction test was performed under the same conditions as in the examples of WO 2020/138360 pamphlet to obtain an NMP solution of polyimide-polyamic acid copolymer (hereinafter also referred to as varnish). It was confirmed that the resulting polyamic acid-imide copolymer had a weight average molecular weight (Mw) of 2,638 and a number average molecular weight (Mn) of 1,326. Therefore, the production method including steps 1 to 3 above is preferable to the production method described in WO 2020/138360 pamphlet from the viewpoint of the molecular weight of the copolymer.

When synthesizing the polyamic acid-imide copolymer, the molar ratio (X ₂ /X ₁ ) of the tetracarboxylic dianhydride component (X ₁ ) and the diamine component (X ₂ ) of the polyamic acid moiety can be obtained From the viewpoint of controlling the coefficient of linear thermal expansion, residual stress, elongation, and YI of the resin film within a desired range, it is preferably 0.85 to 1.2, more preferably 0.90 to 1.1, and 0.92. ~1.00 is more preferred. The above range is preferable in that the reaction with polyimide easily occurs and the degree of haze (Haze value) is lowered.

Further, when synthesizing the polyamic acid-imide copolymer, the molar ratio (X ₄ /X ₃ ) of the tetracarboxylic dianhydride component (X ₃ ) and the diamine component (X ₄ ) in the polyimide part is From the viewpoint of controlling the thermal expansion coefficient, residual stress, elongation, and YI of the resin film to be within the desired range, it is preferably in the range of 0.85 to 2.0, and 0.95 to 1.5. A range is more preferable, and a range of 1.01 to 1.25 is even more preferable. The above range is preferable in that the heat resistance at high temperatures is improved, the decomposition reaction during heating is suppressed, and the yellowness (YI value) and haze (Haze value) are lowered.

Further, when synthesizing the polyamic _acid _- imide copolymer _, the molar ratio ₍ (Number of moles of X ₂ + Number of moles of X ₄ ) / (Number of moles of X ₁ + Number of moles of X ₃ )) is the coefficient of thermal expansion, residual stress, elongation, and YI of the resulting resin film within the desired range From the viewpoint of control, it is preferably in the range of 0.92 to 1.05, more preferably in the range of 0.94 to 1.00. By setting the above range, the molecular weight of the polyamic acid-imide copolymer is easily improved, the processability as a resin composition is improved, coating unevenness when producing a film can be suppressed, and the haze (Haze value ) is preferable from the viewpoint of reduction. In the above range, the terminal amine of the polyamic acid-imide copolymer is reduced, the decomposition reaction during heating is suppressed, the thermal stability in the high temperature range is improved, and the yellowness index (YI value) is lowered. .

When synthesizing a polyamic acid-imide copolymer, the molecular weight can be controlled by adjusting the ratio of the tetracarboxylic dianhydride component and the diamine component, and by adding a terminal blocking agent. The closer the ratio of the acid dianhydride component to the diamine component is to 1:1 and the less the amount of the terminal blocker used, the higher the molecular weight of the polyimide.

It is recommended to use high-purity products as the tetracarboxylic dianhydride component and the diamine component. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more. When multiple types of acid dianhydride components or diamine components are used in combination, it is sufficient if the acid dianhydride component or diamine component as a whole has the above purity, but all types of acid dianhydrides used It is preferred that the component and the diamine component each have the purity specified above.

As the solvent for the reaction, the solvent shown in (d) organic solvent can be used, but it is not limited to this.

As other components, the compounds described in the above (e) imidization catalyst can be used, but are not limited thereto.

The boiling point at normal pressure of the solvent used for polyimide synthesis 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 process will take 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 rough during the drying process, air bubbles may be mixed into the resin film, and a uniform film may not be obtained.

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

[Method for producing polyamic acid]
The polyamic acid according to the fourth embodiment of the present invention is not limited, but can be produced, for example, by the method described in International Publication No. 2017/051827.

<Polyimide copolymer>
Another aspect of the present disclosure provides a film made of a polyimide copolymer obtained by imidizing the (c) polyamic acid-imide copolymer contained in the resin composition. More specifically, general formula (2) below:

{wherein X ₁ and X ₃ represent a tetravalent organic group, X ₂ and X ₄ represent a divalent organic group, and n and m are positive integers}
and a polyimide copolymer characterized by having a structure represented by the general formula (A-1) or the general formula (A-2) as X ₂ . can be done.

The polyimide copolymer preferably satisfies any of the following from the viewpoint of excellent transparency, haze, heat resistance and linear expansion coefficient of the polyimide film containing it:
The diamine component constituting X ₂ in general formula (2) replaces two * in the structure represented by general formula (A-1) or general formula (A-2) with —NH ₂ is a compound that
- X ₃ in the general formula (2) is at least one selected from the group consisting of the structure represented by the general formula (A-3), the structure derived from ODPA, and the structure derived from 6FDA;
- X ₁ in general formula (2) is at least one selected from the group consisting of a BPDA-derived structure, an ODPA-derived structure, and a TAHQ-derived structure;
- the molar ratio (X ₂ /X ₁ ) of X ₁ and X ₂ contained in the general formula (2) is 0.84 to 1.00;
- the molar ratio of X ₃ and X ₄ (X ₄ /X ₃ ) contained in general formula (2) is 1.01 to 2.00; and - X ₁ and X ₂ in general formula (2) The molar ratio of the polyimide structural unit composed of X ₃ and X ₄ to the polyimide structural unit composed of X 3 and X 4 (number of moles of structural unit N: number of moles of structural unit M) is 60: 40 to 95: 5 be;
A structure represented by the above general formula (A-3) as X ₁ or X ₃ , a structure derived from 4,4′-oxydiphthalic dianhydride (ODPA), and 4,4′-(hexafluoroisopropylidene) at least one selected from the group consisting of structures derived from diphthalic anhydride (6FDA);
· X ₄ is at least one selected from the group consisting of structures represented by general formula (A-4), general formula (A-5) and general formula (A-6).

Polyimide copolymer, polyimide film containing it from the viewpoint of excellent transparency, haze, heat resistance and linear expansion coefficient, X ₂ in the general formula (2) is 4-amino-3-fluorophenyl- When it is a group derived from 4-aminobenzoate, the following structures 1 and 2:
Configuration 1. When X ₃ is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X ₄ is 4,4′-diaminodiphenyl sulfone, and/or 2 , a group derived from 2′-bis(trifluoromethyl)benzidine; X ₃ is a group derived from norbornane-2-spiro-α-cyclopentanone a-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride be;
is preferably excluded.

Polyimide copolymer, from the viewpoint of transparency, heat resistance, low residual stress and bending resistance, X ₄ in the general formula (2), X ₃ is 9,9-bis (3,4-dicarboxyphenyl ) In the case of a group derived from fluorene diacid anhydride (BPAF), it is preferable to exclude groups derived from 4,4′-diaminodiphenylsulfone and 2,2′-bis(trifluoromethyl)benzidine.

<Resin composition containing polyamic acid>
Another aspect of the present disclosure is the following general formula (3):

{wherein X ₁ represents a tetravalent organic group, X ₂ represents a divalent organic group, and n is a positive integer}
and (d) the organic solvent and (e) the imidization catalyst described above, and (e) the imidization catalyst is N-tert-butoxycarbonylimidazole (N -Boc-imidazole) and / or an imidazole compound containing 1-methylimidazole, or (e) the imidization catalyst is an imidazole compound, and (e) the content of the imidization catalyst is polyamide Provided is a resin composition characterized by containing 5 parts by mass or more of the acid per 100 parts by mass of the acid.

The resin composition containing the structural unit represented by general formula (3) preferably contains N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and 1-methylimidazole as (e) imidization catalysts. In addition, (e) the content of the imidization catalyst is in the range of 0.02 to 0.15 per 1 mol of the polyamic acid repeating unit having the structural unit represented by the general formula (3). preferable.

X ₁ , X ₂ and n in general formula (3) may be as defined for general formula (1) or (2) above, and X ₁ is represented by general formula (A-3) above. structure, 4,4′-oxydiphthalic dianhydride (ODPA) derived structure, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) derived structure, biphenyltetracarboxylic dianhydride ( BPDA)-derived structure and 4,4′-biphenylbis(trimellitic acid monoester acid anhydride) (TAHQ)-derived structure is preferable, and X ₂ is preferably at least one selected from the group consisting of the structure derived from A group consisting of 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) At least one selected from is preferable, and the structure represented by the above general formula (A-1) is more preferable.

The weight average molecular weight (Mw) of the polyamic acid is preferably 2,639 or more, more preferably 2,639 to 300,000 or 10,000 to 300,000, still more preferably 20,000 to 250,000, 40, 000 to 200,000 are particularly preferred. When the weight average molecular weight is 2,639 or more, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI is low. When the weight-average molecular weight is 300,000 or less, the viscosity and concentration of the polyamic acid-containing varnish are well-balanced, workability is good, and film unevenness during coating is reduced. In addition, when the Mw of the polyamic acid is 170,000 or more, it tends to be excellent in transparency, haze, heat resistance and coefficient of linear expansion, which is preferable, and Mw of 220,000 or more is more preferable. This is remarkable when X ₂ in formula (3) has a structure represented by general formula (A-1) above. In the present disclosure, the weight average molecular weight is a value obtained as a standard polystyrene conversion value using gel permeation chromatography (hereinafter also referred to as GPC).

<Polyimide>
Another aspect of the present disclosure is the following general formula (3):

{wherein X ₃ represents a tetravalent organic group, X ₄ represents a divalent organic group, and m is a positive integer}
Polyimide containing a structural unit M represented by, or the following general formula (16)

{In the formula, P ₁ and P ₂ are the same as P ₁ and P ₂ in general formula (I) or (II), and m is a positive integer. }
A polyimide having a structure represented by is provided.

The polyimide has a structure represented by the general formula (A-3) described above as X ₃ in the general formula (3), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and It is characterized by containing at least one selected from the group consisting of structures derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA).

X ₄ in general formula (3) is as described for X ₄ in general formula (1) or (2) above. The diamine component constituting X ₄ in general formula (3) preferably differs in either diamine composition or diamine species from the same viewpoint as X ₄ in general formula (1) or (2) above. , is more preferably the composition or type of aromatic diamine, and X ₄ in general formula (3) is the above-described general formula (A-4), general formula (A-5), and general It is more preferably at least one selected from the group consisting of structures represented by formula (A-6).

Preferred P ₁ and P ₂ in general formula (I) or (II) are also preferred in polyimides of general formula (16) for the same reasons. The number m of repeating units in general formula (16) is not particularly limited, but may be an integer of 2-150.

The polyimide obtained from the resin composition preferably does not substantially contain an aprotic polar substance with a boiling point of 250 ° C. to 350 ° C., which was contained in the resin composition, but at 1000 ppm or less. may be included.

<<Method for producing resin composition>>
The method for producing the resin composition described above is not particularly limited, and for example, the following method can be used.

<Purification of silicon-containing compound>
The resin composition can be produced by subjecting a polycondensation component containing an acid dianhydride, a diamine, and a silicon-containing compound to a polycondensation reaction. As a method for reducing the total amount of cyclic silicon-containing compounds contained in the resin composition, for example, prior to the polycondensation reaction, the silicon-containing compounds are purified to reduce the total amount of cyclic silicon-containing compounds. are mentioned. Alternatively, after the polycondensation reaction, the resin composition may be purified to reduce the total amount of cyclic silicon-containing compounds.

A method for purifying the silicon-containing compound includes, for example, stripping while blowing an inert gas such as nitrogen gas into the silicon-containing compound in an arbitrary container. 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 still more preferably 240° C. or higher and 300° C. or lower. The vapor pressure for stripping is preferably as low as possible, and is 1000 Pa or less, more preferably 300 Pa or less, still more preferably 200 Pa or less, and still more preferably 133.32 Pa (1 mmHg) or less. The stripping time is preferably 4 hours or more and 12 hours or less, more preferably 6 hours or more and 10 hours or less. By adjusting the above conditions, the monocyclic silicon-containing compound can be efficiently removed, and the total amount of the cyclic silicon-containing compound can be controlled within a preferable range.

<Synthesis of polyimide/polyimide precursor>
A polyimide precursor can be synthesized by a polycondensation reaction of polycondensation components including an acid dianhydride, a diamine, and a silicon-containing compound. In connection with the synthesis of polyimides/polyimide precursors, for example any of the following steps:
- Polycondensation reaction of at least one compound selected from the diamine compounds, at least one compound selected from the acid dianhydride compounds, and other compounds to provide a polyimide precursor and/or polyimide process;
- At least one compound selected from the above diamine compounds, at least one compound selected from the above acid dianhydride compounds, a silicon-containing compound represented by the general formula (13), and other compounds are combined condensation reaction to provide a polyimide precursor and/or polyimide;
Provided is a method for producing a resin composition comprising:
Moreover, it is preferable to use the silicon-containing compound that has been purified as described above. In a preferred embodiment, the polycondensation components consist of dianhydrides, diamines and silicon-containing compounds. The polycondensation reaction is preferably carried out in a suitable solvent. Specifically, for example, after dissolving predetermined amounts of a diamine component and a silicon-containing compound in a solvent, a predetermined amount of acid dianhydride is added to the obtained diamine solution, followed by stirring. The imidization in synthesizing the polyimide may be thermal imidization or chemical imidization using an imidization catalyst.

The molar ratio of the acid dianhydride and the diamine when synthesizing the polyimide/polyimide precursor is acid dianhydride: diamine = 100 from the viewpoint of increasing the molecular weight of the polyimide precursor resin and the slit coating properties of the resin composition. : 90 to 100:110 (0.90 to 1.10 mol parts of diamine to 1 mol part of acid dianhydride) is preferable, 100: 95 to 100: 105 (to 1 mol part of acid dianhydride 0.95 to 1.05 mole parts of diamine) is more preferable.

The molecular weight of the polyimide/polyimide precursor is controlled by adjusting the type of acid dianhydride, diamine and silicon-containing compound, adjusting the molar ratio of acid dianhydride and diamine, adding a terminal blocking agent, adjusting reaction conditions, etc. It is possible. The closer the molar ratio of the acid dianhydride component to the diamine component is to 1:1, and the smaller the amount of the terminal blocking agent used, the higher the molecular weight of the polyimide precursor.

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

The solvent for the reaction is not particularly limited as long as it can dissolve the acid dianhydride component and the diamine component, as well as the resulting polyimide/polyimide precursor, and yield a high-molecular-weight polymer. Examples of such solvents include aprotic solvents, phenolic solvents, ether and glycol solvents, and the like.

Aprotic solvents include, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethyl imidazolidinone, tetramethylurea, and an amide solvent of the following general formula:

{In the formula, Equamid M100 represented by R ₁₂ =methyl group (trade name: manufactured by KJ Chemicals) and Equad B100 represented by R ₁₂ =n-butyl group (trade name: manufactured by KJ Chemicals)} Lactone solvents such as γ-butyrolactone and γ-valerolactone; Phosphorus-containing amide solvents such as hexamethylphosphoricamide and hexamethylphosphine triamide; Sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide and sulfolane; Cyclohexanone , methylcyclohexanone and the like; tertiary amine solvents such as picoline and pyridine; and ester solvents such as acetic acid (2-methoxy-1-methylethyl).

Examples of phenolic solvents 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.

Ether and glycol solvents include, for example, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl ] ether, tetrahydrofuran, 1,4-dioxane, and the like.

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

The boiling point at normal pressure of the solvent used for synthesizing the polyimide/polyimide precursor is preferably 60 to 300°C, more preferably 140 to 280°C, and even more preferably 170 to 270°C. Since the boiling point of the solvent is lower than 300°C, the drying process is shortened. When the boiling point of the solvent is 60° C. or higher, it is difficult for the surface of the resin film to become rough and for bubbles to enter the resin film during the drying process, and a more uniform film can be obtained. In particular, it is preferable to use a solvent having a boiling point of 170 to 270° C. and/or a vapor pressure of 250 Pa or less at 20° C. from the viewpoint of solubility and reduction of edge defects during coating. More specifically, one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and compounds represented by the general formula above are preferred.

The water content in the solvent is preferably, for example, 3,000 ppm by mass or less in order to facilitate the polycondensation reaction. The content of molecules with a molecular weight of less than 1,000 in the resin composition is preferably less than 5% by mass. The presence of molecules with a molecular weight of less than 1,000 in the resin composition is considered to be due to the water content of the solvent and raw materials (acid dianhydride, diamine) used during synthesis. That is, it is thought that the acid anhydride groups of some acid dianhydride monomers are hydrolyzed by water to form carboxyl groups, which remain in a low-molecular state without increasing the molecular weight. Therefore, it is preferable that the water content of the solvent used in the above polycondensation reaction is as small as possible. The water content of the solvent is preferably 3,000 mass ppm or less, more preferably 1,000 mass ppm or less. Similarly, the amount of water contained in the raw material is preferably 3,000 ppm by mass or less, more preferably 1,000 ppm by mass or less.

The water content of the solvent depends on the grade of the solvent used (dehydration grade, general-purpose grade, etc.), solvent container (bottle, 18L can, canister can, etc.), storage condition of the solvent (presence or absence of rare gas inclusion, etc.), and from opening to use. time (whether to use immediately after opening or after the passage of time after opening, etc.) is considered to be involved. Presumably, replacement of the reactor with rare gas before synthesis, presence or absence of circulation of rare gas during synthesis, etc. also play a role. Therefore, when synthesizing polyimide precursors, it is recommended to use high-purity materials as raw materials, use solvents with low water content, and take measures to prevent water from entering the system before and during the reaction. be done.

When dissolving each polycondensation component in the solvent, it may be heated as necessary. From the viewpoint of obtaining a polyimide precursor having a high degree of polymerization, the reaction temperature during synthesis of the polyimide precursor is preferably 0° C. to 120° C., 40° C. to 100° C., or 60° C. to 100° C., and the polymerization time is may preferably be from 1 to 100 hours, or from 2 to 10 hours. A polyimide precursor having a uniform degree of polymerization can be obtained by setting the polymerization time to 1 hour or more, and a polyimide precursor having a high degree of polymerization can be obtained by setting the polymerization time to 100 hours or less.

The resin composition may contain other additional polyimide precursors in addition to the polyimides/polyimide precursors 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 is, relative to the total amount of polyimide/polyimide precursor in the resin composition, It is preferably 30% by mass or less, more preferably 10% by mass or less.

The polyimide precursor may be partially imidized (partially imidized). By partially imidizing the polyimide precursor, viscosity stability during storage of the resin composition can be improved. In this case, the imidization rate is preferably 5% or more, more preferably 8% or more, from the viewpoint of balancing the solubility of the polyimide precursor in the resin composition and the storage stability of the solution. It is 80% or less, more preferably 70% or less, still more preferably 50% or less. This partial imidization is obtained by heating the polyimide precursor for dehydration and ring closure. This heating is preferably carried out at a temperature of 120 to 200° C., more preferably 150 to 185° C., still more preferably 150 to 180° C., for preferably 15 minutes to 20 hours, more preferably 30 minutes to 10 hours. .

Part or all of the carboxylic acid is esterified by adding N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal to the polyimide/polyimide precursor obtained by the above reaction and heating. may be used as a polyimide precursor. Esterification can improve viscosity stability during storage. These ester-modified polyamic acids are prepared by sequentially reacting the above acid dianhydride component with 1 equivalent of a monohydric alcohol relative to the acid anhydride group, and a dehydration condensation agent such as thionyl chloride or dicyclohexylcarbodiimide, It can also be obtained by a method of condensation reaction with a diamine component.

<Synthesis of polyimide>
As a more preferred embodiment, the polyimide varnish is obtained by dissolving the acid 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 imidation outside the system. By removing it, a polyimide solution containing polyimide and a solvent (also referred to as polyimide varnish) can be produced. Here, the reaction conditions are not particularly limited, but for example, the reaction temperature is 0° C. to 180° C. and the reaction time is 3 to 72 hours. In order to sufficiently advance the reaction with the sulfone group-containing diamines, it is preferable to carry out the reaction by heating at 180° C. for about 12 hours. Moreover, it is preferable that the atmosphere is an inert atmosphere such as argon or nitrogen during the reaction.

<Preparation of resin composition>
When the solvent used when synthesizing the polyimide precursor and the solvent to be contained in the resin composition are the same, the synthesized polyimide/polyimide precursor solution can be used as it is as the resin composition. If necessary, at a temperature range of room temperature (25° C.) to 80° C., a resin composition is prepared by adding a further solvent and one or more additional components to the polyimide precursor and stirring and mixing. may This stirring and mixing can be performed using an appropriate device such as a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) equipped with stirring blades, a rotation-revolution mixer, or the like. If necessary, the resin composition may be heated to 40°C to 100°C.

On the other hand, when the solvent used in synthesizing the polyimide/polyimide precursor is different from the solvent to be contained in the resin composition, the solvent in the synthesized polyimide precursor solution is removed by, for example, reprecipitation, solvent distillation, or the like. may be removed by any suitable method to isolate the polyimide/polyimide precursor. Next, a desired solvent and, if necessary, additional components are added to the isolated polyimide precursor at a temperature range of room temperature (25° C.) to 80° C., and mixed with stirring to prepare a resin composition. You may

In particular, in the preparation of the resin composition, it is particularly preferable to finally add an aprotic polar substance with a boiling point of 250°C to 350°C after synthesizing the polyimide/polyimide precursor. Thereby, the in-plane uniformity of the film thickness of the obtained polyimide resin film can be improved, and the yellowness index (YI value) can also be reduced.

After preparing the resin composition as described above, the resin composition is heated, for example, at 130 to 200° C. for, for example, 5 minutes to 2 hours, thereby partially reducing the polyimide precursor to such an extent that the polymer does not precipitate. Dehydration imidization may be performed (partial imidization). The imidization rate can be controlled by controlling the heating temperature and heating time. By partially imidizing the polyimide precursor, viscosity stability during storage of the resin composition can be improved.

From the viewpoint 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, still more preferably 3,000 to 20,000 mPa·s. is s. Specifically, the viscosity is preferably 500 mPa·s or more, more preferably 1,000 mPa·s or more, and still more preferably 3,000 mPa·s or more, in order to prevent leakage from the slit nozzle. It is preferably 100,000 mPa·s or less, more preferably 50,000 mPa·s or less, and still more preferably 20,000 mPa·s or less, in terms of preventing clogging of the slit nozzle.

If the solution viscosity of the resin composition during synthesis of the polyimide/polyimide precursor is higher than 200,000 mPa·s, there is a risk that stirring during synthesis will become difficult. However, even if the solution becomes highly viscous during synthesis, it is possible to obtain a resin composition having a viscosity that is easy to handle by adding a solvent and stirring after the completion of the reaction. The solution viscosity of the resin composition is a value measured at 23° C. using an E-type viscometer (eg, VISCONICEHD, manufactured by Toki Sangyo).

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, and still more preferably 2,000 mass ppm. Below, more 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, particularly preferably 100 mass ppm or less.

<<Polyimide resin film and its manufacturing method>>
A polyimide resin film (hereinafter also referred to as a polyimide film) can be provided using the resin composition described above. The method for producing a polyimide film described above includes a coating step of applying a 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 polyimide resin film. from the support.

<Coating process>
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 has heat resistance to the heating temperature in the subsequent film forming step (heating step) and has good peelability in the peeling step. Examples of the support include glass substrates such as alkali-free glass substrates; silicon wafers; PET (polyethylene terephthalate), OPP (oriented polypropylene), polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamideimide, and polyetherimide. , polyether ether ketone, polyether sulfone, polyphenylene sulfone, polyphenylene sulfide, etc.; metal substrates such as stainless steel, alumina, copper, nickel, etc.;

When forming a thin-film polyimide molded body, for example, a glass substrate, a silicon wafer, or the like is preferable. ), OPP (oriented polypropylene) or the like is preferable.

Coating methods generally include doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, bar coater, etc.; spin coating, spray coating, dip coating, etc.; screen printing. and printing techniques such as gravure printing. Application by slit coating is preferable for the resin composition. 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, and is preferably about 1 to 1,000 μm. The temperature in the coating step may be room temperature, or the resin composition may be heated to, for example, 40° C. to 80° C. in order to lower the viscosity and improve workability.

<Optional drying process>
The coating step may be followed by a drying step, or the drying step may be omitted and the next film-forming step (heating step) may proceed directly. The drying step is performed for the purpose of removing the organic solvent in the resin composition. When performing the drying step, for example, a hot plate, a box-type dryer, a conveyor-type dryer, or the like can be used. The temperature of the drying step is preferably 80°C to 200°C, more preferably 100°C to 150°C. The duration 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 the support.

<Film forming process>
Subsequently, a film forming process (heating process) is performed. The heating step is a step of removing the organic solvent contained in the coating film and advancing the imidization reaction of the polyimide precursor in the coating film to obtain a polyimide resin film. This heating step can be carried out using, for example, an inert gas oven, a hot plate, a box-type dryer, a conveyor-type dryer, or the like. This step may be performed simultaneously with the drying step, or both steps may be performed sequentially.

The heating step may be performed in an air atmosphere, but from the viewpoint of safety, good transparency of the resulting polyimide film, low thickness direction retardation (Rth) and low YI value, it is performed in an inert gas atmosphere. preferably. Examples of inert gases include nitrogen and argon. The heating temperature may be appropriately set according to the type of polyimide precursor and the type of solvent in the resin composition, but is preferably 250°C to 550°C, more preferably 300°C to 450°C. If the temperature is 250° C. or higher, the imidization proceeds favorably, and if it is 550° C. or lower, problems such as deterioration of the transparency and heat resistance of the resulting polyimide film can be avoided. The heating time is preferably about 0.1 hour to 10 hours.

In particular, when the resin composition contains an aprotic polar substance with a boiling point of 250° C. to 350° C., it remains in the film even at a temperature of 250° C. or higher in the polyimide heating process. Plays a role as a plasticizer. As a result, the resin becomes soft and fluid, and the resulting polyimide resin film has improved in-plane uniformity of film thickness and reduced YI.

The oxygen concentration in the ambient atmosphere in the above heating step is preferably 2,000 mass ppm or less, more preferably 100 mass ppm or less, and still more preferably 10 mass ppm or less, from the viewpoint of the transparency and YI value of the resulting polyimide film. is. By heating in an atmosphere with an oxygen concentration of 2,000 ppm by mass or less, the YI value of the resulting polyimide film can be made 30 or less.

<Peeling process>
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. Examples of the peeling process include the following aspects (1) to (4).

(1) After producing a structure containing a polyimide resin film/support by the above method, a laser is irradiated from the support side of the structure to ablate the interface between the support and the polyimide resin film. A method for peeling polyimide resin. Types of lasers include solid-state (YAG) lasers, gas (UV excimer) lasers, and the like. It is preferable to use a spectrum with a wavelength of 308 nm or the like (see Japanese Patent Publication No. 2007-512568, Japanese Patent Publication No. 2012-511173, etc.).

(2) A method of forming a release layer on a support before coating the resin composition on the support, then obtaining a structure comprising a polyimide resin film/release layer/support, and peeling off the polyimide resin film. . Examples of the release layer include parylene (registered trademark, manufactured by Japan Parylene LLC) and tungsten oxide; vegetable oil-based, silicone-based, fluorine-based, and alkyd-based release agents may be used (JP 2010-067957 A). No. 2013-179306, etc.).
This method (2) and the laser irradiation of method (1) may be used in combination.

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

(4) After obtaining a structure containing a polyimide resin film/support by the above method, an adhesive film is attached to the polyimide resin film surface to separate the adhesive film/polyimide resin film from the support, and then from the adhesive film. A method for separating a polyimide resin film.

Among these peeling methods, method (1) or (2) is preferable from the viewpoint of the front and back refractive index difference, YI value, and elongation of the obtained polyimide resin film. From the viewpoint of the difference in refractive index between the front and back surfaces of the resulting polyimide resin film, it is more preferable to carry out method (1), that is, the irradiation step of irradiating a laser from the support side prior to the peeling step. In method (3), when copper is used as the support, the YI value of the resulting polyimide resin film tends to increase and the elongation tends to decrease. This is believed to be the effect of copper ions.

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

<Polyimide film>
In another aspect of the present disclosure, when measured at a film thickness of 10 μm, the tensile modulus at 25° C. is 6 GPa or more, the tensile modulus at 350° C. is 0.5 GPa or more, and the yellowness (YI value ) is 12 or less.

The polyimide film is preferably prepared using the above-described polyamic acid-imide copolymer and/or polyimide copolymer as raw materials. The haze value (Haze value) of the polyimide film is preferably less than 0.5% from the viewpoint of balancing transparency, heat resistance and linear expansion coefficient, and / or 1 at 430 ° C. of the polyimide film The rate of change in yellowness (YI value) when kept for a period of time is preferably 20% or less from the viewpoint of balancing the haze value, heat resistance, and coefficient of linear expansion.

Resin films produced using the polyamic acid-imide copolymer, polyamic acid, polyimide, and resin composition described above are applied, for example, as semiconductor insulating films, TFT-LCD insulating films, electrode protective films, and the like. In addition, it can be used particularly preferably as a substrate in the production of flexible devices. Flexible devices to which the resin film and laminate can be applied include, for example, flexible displays, flexible solar cells, flexible touch panel electrode substrates, flexible lighting, and flexible batteries.

《Applications of Polyimide Film》
The polyimide film obtained from the resin composition described above can be used, for example, as a semiconductor insulating film, a thin film transistor liquid crystal display (TFT-LCD) insulating film, an electrode protective film, a liquid crystal display, an organic electroluminescence display, a field emission display. , as a transparent substrate of a display device such as electronic paper.

In particular, polyimide films can be suitably used as flexible substrates for thin film transistor (TFT) substrates, color filter substrates, touch panel substrates, and transparent conductive films (ITO, Indium Thin Oxide) in the production 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 circuit boards, flexible color filters, and surface cover lenses for smartphones. can.

The process of forming TFTs on flexible substrates using polyimide films is typically carried out at a wide temperature range of 150°C to 650°C. Specifically, when fabricating a TFT device using amorphous silicon, a process temperature of 250° C. to 350° C. is generally required, and the polyimide film must be able to withstand that temperature. It is necessary to appropriately select a polymer structure having a glass transition temperature and thermal decomposition initiation temperature higher than the process temperature.

When manufacturing a TFT device using a metal oxide semiconductor (such as IGZO), a process temperature of 320° C. to 400° C. is generally required, and the polyimide film must be able to withstand that temperature. It is necessary to appropriately select a polymer structure having a glass transition temperature and thermal decomposition initiation temperature higher than the maximum temperature of the fabrication process.

When manufacturing a TFT device using low-temperature polysilicon (LTPS), a process temperature of 380° C. to 520° C. is generally required, and the polyimide film must be able to withstand that temperature. It is necessary to appropriately select a glass transition temperature higher than the maximum temperature and a thermal decomposition initiation temperature. On the other hand, due to these thermal histories, the optical properties of polyimide films (in particular, light transmittance, retardation properties and YI value) tend to decrease as they are exposed to high-temperature processes. However, the polyimide obtained from the polyimide precursor has good optical properties even after thermal history.

Below, a method for manufacturing a display and a laminate will be described as an application example of the polyimide film.

<Display manufacturing method>
In one aspect of the present disclosure, a display manufacturing method includes a coating step of coating a resin composition on the surface of a support, and 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, and a peeling step of peeling the polyimide film with the element formed thereon from the support.

1. Production Example of Flexible Organic EL Display FIG. 1 is a schematic diagram showing a structure above a polyimide substrate of a top-emission flexible organic EL display as an example of a display according to one embodiment of the present disclosure. The organic EL structure section 25 in FIG. 1 will be described. For example, the organic EL element 250a that emits red light, the organic EL element 250b that emits green light, and the organic EL element 250c that emits blue light are arranged as one unit in a matrix. ) 251 defines the light emitting region of each organic EL element. Each organic EL element is composed of a lower electrode (anode) 252 , a hole transport layer 253 , a light emitting layer 254 and an upper electrode (cathode) 255 . TFTs 256 (low-temperature polysilicon (LTPS) or metal oxide film) for driving organic EL elements are formed on the lower layer 2a showing a CVD multilayer film (multi-barrier layer) made of silicon nitride (SiN) or silicon oxide (SiO). , an interlayer insulating film 258 having a contact hole 257, and a plurality of lower electrodes 259 are provided. The organic EL elements are enclosed by the sealing substrate 2b, and a hollow portion 261 is formed between each organic EL element and the sealing substrate 2b.

The manufacturing process of a flexible organic EL display includes a process of producing a polyimide film on a glass substrate support, manufacturing an organic EL substrate shown in FIG. It includes an assembly step of bonding together and a peeling step of peeling the organic EL display produced on the polyimide film from the glass substrate support. Well-known manufacturing processes can be applied to the organic EL substrate manufacturing process, the sealing substrate manufacturing process, and the assembly process. An example will be given below, but it is not limited to this. The peeling process is the same as the polyimide film peeling process described above.

For example, referring to FIG. 1, first, a polyimide film is produced on a glass substrate support by the above method, and a multilayer of silicon nitride (SiN) and silicon oxide (SiO) is formed thereon by a CVD method or a sputtering method. A multi-barrier layer (lower substrate 2a in FIG. 1) having a structure is produced, and a metal wiring layer for driving TFTs is produced thereon using a photoresist or the like. An active buffer layer of SiO or the like is fabricated on top of this using the CVD method, and a TFT device (TFT 256 in FIG. 1) of metal oxide semiconductor (IGZO) or low temperature polysilicon (LTPS) is fabricated thereon. After manufacturing a TFT substrate for a flexible display, an interlayer insulating film 258 having a contact hole 257 is formed using a photosensitive acrylic resin or the like. An ITO film is formed by a sputtering method or the like, and a lower electrode 259 is formed so as to form a pair with the TFT.

Next, after forming partition walls (banks) 251 with photosensitive polyimide or the like, a hole transport layer 253 and a light emitting layer 254 are formed in each space partitioned by the partition walls. An upper electrode (cathode) 255 is formed 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) and an organic EL material emitting green light (corresponding to the organic EL element 250a emitting red light in FIG. 1) (corresponding to the organic EL element 250b that emits green light) and an organic EL material that emits blue light (corresponding to the organic EL element 250c that emits blue light in FIG. 1) by a known method. to fabricate an organic EL substrate. By sealing the organic EL substrate with a sealing film or the like (sealing substrate 2b in FIG. 1) and peeling the device above the polyimide substrate from the glass substrate support by a known peeling method such as laser peeling, the top An emission type flexible organic EL display can be produced. When using the polyimide according to one aspect of the present disclosure, a see-through flexible organic EL display can be produced. A bottom emission type flexible organic EL display may be produced by a known method.

Flexible Liquid Crystal Display Fabrication Examples Polyimide films according to one aspect of the present disclosure can be used to fabricate flexible liquid crystal displays. As a specific production method, a polyimide film is produced on a glass substrate support by the above method, and the film is made of amorphous silicon, metal oxide semiconductor (IGZO, etc.), and low-temperature polysilicon using the above method. A TFT substrate is produced. Separately, according to the coating step and the film forming step according to one aspect of the present disclosure, a polyimide film is produced on a glass substrate support, and a color resist or the like is used according to a known method to form a color filter glass substrate equipped with a polyimide film. (CF substrate) is produced. On one of the TFT substrate and the CF substrate, a sealing material made of thermosetting epoxy resin or the like is applied by screen printing in a frame-like pattern omitting the part of the liquid crystal injection port. Spherical spacers made of plastic or silica with a diameter of

Next, the TFT substrate and the CF substrate are attached together, and the sealing material is cured. Then, a liquid crystal material is injected into the space surrounded by the TFT substrate, the CF substrate, and the sealing material by a depressurization method, 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. do. 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 a laser peeling method or the like, whereby a flexible liquid crystal display can be produced.

<Method for manufacturing laminate>
A method for producing a laminate according to one aspect of the present disclosure includes a coating step of coating a resin composition on the surface of a support, and a film formation of heating the resin composition to form a polyimide film (polyimide resin film). and a device forming step of forming devices on the polyimide film.

Examples of the elements in the laminate include those exemplified for the production of flexible devices such as the flexible display described above.
A glass substrate, for example, can be used as the support. Preferred specific procedures for the coating step and the film forming step are the same as those described for the method for producing the polyimide film above. In the element forming step, the element is formed on the polyimide resin film as the flexible substrate formed on the support. Thereafter, optionally, in a peeling step, the polyimide resin film with the element formed thereon and the element may be peeled off from the support.
A method for manufacturing a flexible device according to an aspect of the present disclosure includes manufacturing a laminate by the method for manufacturing a laminate described above.

Although the embodiments of the present invention have been described above, the present invention is not limited to these, and can be modified as appropriate without departing from the scope of the invention.

Although the present invention will be described in more detail below based on examples, these are described for the sake of explanation, and the scope of the present invention is not limited to the following examples.

Various evaluations in Examples and Comparative Examples were performed as follows.

<Measurement of Weight Average Molecular Weight and Number Average Molecular Weight>
Weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions.

As a solvent, N,N-dimethylformamide (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd., for high-performance liquid chromatography, 24.8 mmol / L of lithium bromide monohydrate immediately before measurement (manufactured by FUJIFILM Wako Pure Chemical Industries, purity 99.5%) and 63.2 mmol/L phosphoric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., for high-performance liquid chromatograph) and dissolved therein) were used. A calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (Easical Type PS-1, manufactured by Agilent Technologies).
Apparatus: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: 2 Tsk gel Super HM-H (manufactured by Tosoh Corporation)
Flow rate: 0.5 mL/min Column temperature: 40°C
Detector: UV-8220 (UV-VIS: UV-visible spectrophotometer, manufactured by Tosoh Corporation)

<Evaluation of glass transition temperature (Tg)>
The glass transition temperature (Tg) in the temperature range of 50 to 500° C. was measured by thermomechanical analysis using a test piece cut from the polyimide film into a size of 3 mm×20 mm. Using Seiko Instruments Inc. (EXSTAR6000) as a measuring device, under the conditions of a tensile load of 49 mN, a temperature increase rate of 10 ° C./min and a nitrogen stream (flow rate of 100 mL/min), the temperature in the range of 50 ° C. to 500 ° C. Measurements of specimen elongation were made. The glass transition temperature of the polyimide film (10 μm thick) was obtained from the inflection point of the obtained curve. Those in which no inflection point was observed in the range of 50° C. to 500° C. are considered to have a Tg of 500° C. or higher, and are sometimes shown as “-” in the table below.

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

The amount of warpage of this wafer was measured using a residual stress measuring device (manufactured by Tencor, model name: FLX-230) to evaluate the residual stress generated between the silicon wafer and the resin film.
S: Residual stress is more than -5 MPa and 15 MPa or less (residual stress evaluation "excellent")
A: Residual stress is more than 15 MPa and 25 MPa or less (residual stress evaluation "good")
B: Residual stress is over 25 MPa (residual stress evaluation "bad")

<Evaluation of yellowness (YI value) and haze (Haze value)>
Each resin composition was applied on a 100 mm square (0.7 mm thick) Eagle XG glass with a spin coater and prebaked at 80° C. for 30 minutes. After that, the oxygen concentration in the chamber is adjusted to 10 ppm by mass or less, heat curing treatment (curing treatment) is performed at 430 ° C. for 1 hour, and the glass substrate with a polyimide resin film having a film thickness of 10 μm after curing is attached. was made. For the obtained polyimide-coated glass substrate, the yellowness (YI value) was measured using a D65 light source with a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd., and a spectrophotometer manufactured by Konica Minolta Co., Ltd. (CM −3600 A) using a D65 light source to measure the haze (haze value).
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 0.2% or less (Haze value evaluation “S”)
A: Haze value is more than 0.2% and 0.5% or less (Haze value evaluation “A”)
B: Haze value is over 0.5% (Haze value evaluation "B")

<Evaluation of bending resistance>
Each resin composition was applied by a spin coater onto a 6-inch silicon wafer having a thickness of 625 .mu.m.+-.25 .mu.m on which aluminum (Al) was previously sputtered to a thickness of about 100 nm, and prebaked at 100.degree. C. for 7 minutes. After that, the oxygen concentration in the chamber was adjusted to 10 ppm by mass or less, heat curing treatment (cure treatment) was performed at 430 ° C. for 1 hour, and Al sputtering with a polyimide resin film having a film thickness of 10 μm after curing was attached. A film-coated silicon wafer was produced. The prepared sample was immersed in a 10% by mass hydrochloric acid aqueous solution for one day, and the polyimide resin film was peeled off from the silicon wafer. A test piece was prepared by cutting the peeled polyimide film into a size of 15 mm×100 mm.

Using an MIT-type repeated bending tester (MIT-DA, manufactured by Toyo Seiki), a load of 250 g is applied to the prepared test piece, and the bending radius (R) is 2 mm, the bending angle is 135 °, and the speed is 90 times / minute. A 100,000 reciprocating bending test was conducted under the conditions of . After the test, the samples were removed from the apparatus, and visually evaluated as A when there was no damage, and as B when there was damage.

<Evaluation of storage stability>
The resin composition was stored at 23 ° C., and after 1 week, a glass substrate with a polyimide resin film was prepared in the same evaluation as <Evaluation of yellowness (YI value) and haze (Haze value)>. A haze value) of 0.5% or less was rated as "A", and 0.5% or more was rated as "B".

<Evaluation of elastic modulus>
The modulus of elasticity was measured by thermomechanical analysis using a test piece obtained by cutting a polyimide film into a size of 3 mm×20 mm. Using Seiko Instruments Inc. (EXSTAR6000) as a measuring device, the set temperature is constant at 25 ° C. or 350 ° C., under a nitrogen atmosphere, the load is changed at an initial tensile load of 20 mN and a load change rate of 100 mN / min, and the maximum is 1200 mN. Elongation was measured by applying a load to The elastic modulus of the polyimide film (10 μm thick) was obtained from the slope of the obtained curve. "B" in Table 4 also indicates that the film was brittle and broke during measurement, or that had a low Tg and broke during the measurement. Evaluation criteria are as follows.
Elastic modulus S at 25°C: Elastic modulus of 6 GPa or more (Evaluation of elastic modulus "S")
B: YI value is 6 GPa or less (evaluation of elastic modulus "B")
Elastic modulus S at 350°C: Elastic modulus of 0.5 GPa or more (Evaluation of elastic modulus "S")
B: YI value is 0.5 GPa or less (evaluation of elastic modulus "B")

<Sputter reheating test>
An aluminum (Al) film of about 100 nm was sputtered onto a glass substrate with a polyimide resin film prepared in the same manner as <Evaluation of yellowness index (YI value) and haze value (Haze value)>. The Al film was deposited on the polyimide film.

The prepared sample was adjusted so that the oxygen concentration in the chamber was 10 ppm by mass or less, and heat-treated at 430°C for 1 hour to obtain a glass substrate with a polyimide resin film having a thickness of 10 µm. The Al-sputtered polyimide-coated glass substrate thus obtained was evaluated as "S" when there was no visible swelling or breakage, and as "B" when there was a tear or swelling.

<Evaluation of 430 ° C. reheating test>
A glass substrate with a polyimide resin film prepared in the same manner as <Evaluation of yellowness index (YI value) and haze value (Haze value)> was evaluated using an apparatus.

After measuring the YI value (YI (A)) of the glass substrate with polyimide obtained by heat curing at 430 ° C. using a D65 light source with a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd., After adjusting the oxygen concentration to 10 ppm by mass or less, heat treatment was performed at 430° C. for 1 hour to obtain a glass substrate with a polyimide resin film having a thickness of 10 μm.

For the obtained polyimide-coated glass substrate, the YI value (YI (B)) was measured again using a D65 light source with a Spectotometer (SE6000) manufactured by Nippon Denshoku Industries Co., Ltd., and the rate of change with respect to the YI value before heating was calculated. evaluated. The YI value (change rate) was determined by the following formula.
YI value change rate: ((YI (B) - YI (A)) / YI (A) x 100 (%))
S: YI value change rate is 0% or more and 10% or less (YI value (change rate) evaluation "S")
A: YI value change rate is more than 10% and 20% or less (YI value (change rate) evaluation "A")
B: YI value change rate is over 20% (YI value (change rate) evaluation "B")

<IR cure defect evaluation>
In this evaluation, assuming mass production, the amount of defects on the surface of the polyimide film was evaluated when the resin composition was continuously subjected to IR (infrared) heat curing (cure) treatment.
On an alkali-free glass substrate (hereinafter also referred to as “glass substrate” or simply “substrate”) of 100 mm length × 100 mm width × 0.5 mm thickness, in an area 5 mm inside from the edge of the glass substrate, The resin composition was applied so that the film thickness after curing was 10 μm. A slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions) was used for coating. Using a vacuum dryer (manufactured by Tokyo Ohka Kogyo Co., Ltd.), the solvent was removed from the resulting coated glass substrate under the conditions of 80° C., 100 Pa, and 30 minutes to obtain a coated film sample.

After that, using an IR cure furnace AMK-1707 (light source: ceramic heater, furnace volume 50 L, manufactured by AMK), 10 coated film samples of the same resin composition were set and heated at 120 ° C. for 10 minutes in a nitrogen atmosphere. After that, the temperature was raised at 10°C/min and heated at 430°C for 60 minutes. This was regarded as one batch, and 5 batches were heat-treated using the same resin composition (10 wafers x 5 batches, 50 wafers in total were processed). When another composition was treated, the IR curing furnace was preheated at 500° C. for 5 hours or longer, and pipes such as ducts were cleaned before use. Then, using the fifth polyimide resin film from the top of the fifth batch, defects on the surface of the polyimide resin film were evaluated using a defect inspection apparatus (LCF-5505XU, manufactured by Takano Co., Ltd.). The number of defects of 10 µm or more was detected. Evaluation was made according to the following criteria.
Less than 25 defects: 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 100 or more and less than 200: D (acceptable)
The number of defects is 200 or more: E (impossible)

<Degassing evaluation>
When a polyimide resin film is used as a TFT substrate, an inorganic film (for example, SiN) is formed on the obtained polyimide resin film, and the inorganic film is annealed. If degassing occurs during this annealing process, the sample becomes defective, so the higher the degassing start temperature, the better. This degassing start temperature was evaluated by the following method.

On an alkali-free glass substrate (hereinafter also referred to as “glass substrate” or simply “substrate”) of 100 mm length × 100 mm width × 0.5 mm thickness, the glass substrate of the examples and comparative examples was applied in an area 5 mm inside from the edge of the glass substrate. The resin composition was applied so that the film thickness after curing was 10 μm. A slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions) was used for coating. Using a vacuum dryer (manufactured by Tokyo Ohka Kogyo Co., Ltd.), the solvent was removed from the resulting coated glass substrate under the conditions of 80° C., 100 Pa, and 30 minutes to obtain a coated film sample. After that, 5 coated film samples of the resin composition are set, and after heating at 120 ° C. for 10 minutes in a nitrogen atmosphere using an IR cure furnace AMK-1707 (light source: ceramic heater, furnace volume 50 L, manufactured by AMK). , and heated at 430° C. for 60 minutes to obtain a polyimide resin film formed on a glass substrate.

A SiN film having a thickness of 100 nm was formed on the obtained polyimide resin film by plasma CVD. The obtained glass substrate on which the laminate of SiN/polyimide resin film was formed was subjected to heat treatment in an IR curing furnace AMK-1707 under the following conditions.
a. After heating at 120° C. for 10 minutes in a nitrogen atmosphere, the temperature was raised at a rate of 10° C./min and heated at 480° C. for 60 minutes b. After heating at 120° C. for 10 minutes in a nitrogen atmosphere, the temperature was raised at a rate of 10° C./min and heated at 470° C. for 60 minutes c. After heating at 120° C. for 10 minutes in a nitrogen atmosphere, the temperature was raised at a rate of 10° C./min and heated at 460° C. for 60 minutes d. After heating at 120° C. for 10 minutes in a nitrogen atmosphere, the temperature was raised at a rate of 10° C./min and heated at 450° C. for 60 minutes e. After heating at 120° C. for 10 minutes in a nitrogen atmosphere, the temperature was raised at 10° C./min, heated at 440° C. for 60 minutes, and the presence or absence of degassing was evaluated according to the following criteria;
above a. SiN film blisters/does not occur under the conditions: A (Hide)
above b. SiN film blisters under the conditions: B (excellent)
above c. SiN film blisters under the conditions: C (good)
above d. Blistering occurs in the SiN film under the conditions of: D (Possible)
above e. SiN film blisters under the conditions: E (impossible)

[Synthesis Examples 1 and 2]
(Synthesis Example 1-1-1)
After purging a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube with nitrogen, 20 g of N-methyl-2-pyrrolidone (NMP) and 9,9-bis(4-aminophenyl)fluorene (44 BAFL) were added. was added and stirred to dissolve 44BAFL. Then, 20.00 mmol of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 11.41 g of N-methyl-2-pyrrolidone (NMP), and 21.76 g of toluene were added at 40°C. After the addition, a polymerization reaction 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. After 4 hours of reaction, the imide had a weight average molecular weight (Mw) of 19,178 and a number average molecular weight (Mn) of 8,283.

After 4 hours of reaction, the internal temperature was cooled to 80°C, 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 nitrogen flow. After stirring for 2 hours at 60° C., the polymerization reaction was carried out overnight at room temperature. Thereafter, the above NMP was added to adjust the solid content to 12% by mass, thereby obtaining an NMP solution of polyimide-polyamic acid copolymer (hereinafter also referred to as varnish). The resulting polyamic acid-imide copolymer had a weight average molecular weight (Mw) of 155,382 and a number average molecular weight (Mn) of 64,063.

(Synthesis Example 1-1-2)
(a) Polyimide Synthesis After purging a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube with nitrogen, 20 g of N-methyl-2-pyrrolidone (NMP), 9,9-bis(4-aminophenyl ) 22.22 mmol of fluorene (44BAFL) was added and stirred to dissolve 44BAFL. Then, 20.00 mmol of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 11.41 g of N-methyl-2-pyrrolidone (NMP), and 21.76 g of toluene were added at 40°C. After the addition, a polymerization reaction 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. After 4 hours of reaction, the imide had a weight average molecular weight (Mw) of 19,804 and a number average molecular weight (Mn) of 8,886. After 4 hours of reaction, the inside temperature was cooled to 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).

(b) Synthesis of polyamic acid After purging a 500 ml four-necked flask with nitrogen, 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 stirred at 80° C. for 5 hours under nitrogen flow. After that, the polymerization reaction was carried out overnight at room temperature. Thereafter, the above NMP was added to adjust the solid content to 20% by mass, thereby obtaining an NMP solution of polyamic acid (hereinafter also referred to as polyamic acid varnish). The polyamic acid obtained had a weight average molecular weight (Mw) of 73,044 and a number average molecular weight (Mn) of 34,917.

(c) polyamic acid-imide copolymer synthesis The polyimide varnish obtained in (a) and the polyamic acid varnish obtained in (b) are mixed and stirred at room temperature for 24 hours to produce a polyamic acid-imide copolymer. of NMP solution was obtained.

(Synthesis Example 1-12)
After purging a 500 ml four-necked flask equipped with a reflux tube and a Dean-Stark tube with nitrogen, 20 g of N-methyl-2-pyrrolidone (NMP) and 9,9-bis(4-aminophenyl)fluorene (44 BAFL) were added. was added and stirred to dissolve 44BAFL. Then, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) 10.00 mmol, biphenyltetracarboxylic dianhydride 10.00 mmol, N-methyl-2-pyrrolidone (NMP) 11 After adding .41 g and 21.76 g of toluene at 40° C., a polymerization reaction 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. After 4 hours of reaction, the imide had a weight average molecular weight (Mw) of 19,342 and a number average molecular weight (Mn) of 9,242.

After 4 hours of reaction, the internal temperature was cooled to 80°C, 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 polymerized at 80° C. for 1 hour under nitrogen flow. reacted. Thereafter, the above NMP was added to adjust the solid content to 12% by mass, thereby obtaining an NMP solution of polyimide-polyamic acid copolymer (hereinafter also referred to as varnish). The resulting polyamic acid-imide copolymer had a weight average molecular weight (Mw) of 40,578 and a number average molecular weight (Mn) of 19,128.

(Synthesis Examples 1-2 to 1-11, and 1-13 to 1-30)
In the above Synthesis Example 1-1-1, polyamic acid-imide copolymerization was carried out in the same manner as in Synthesis Example 1-1-1, except that the types and amounts of raw materials were changed as shown in Table 1. Got varnish.

(Synthesis Example 1-1-3)
To the NMP solution synthesized in Synthesis Example 1-1-1 above, 0.04 mol of 1-methylimidazole was added per 1 mol of the repeating unit of the polyimide-polyamic acid copolymer to obtain a polyamic acid-imide copolymer varnish. rice field.

(Synthesis Example 1-1-4)
To the NMP solution synthesized in Synthesis Example 1-1-1 above, 0.13 mol of 1-methylimidazole was added per 1 mol of the repeating unit of the polyimide-polyamic acid copolymer to obtain a polyamic acid-imide copolymer varnish. rice field.

(Synthesis Example 1-1-5)
To the NMP solution synthesized in Synthesis Example 1-1-1 above, 0.13 mol of N-Boc-imidazole was added per 1 mol of the repeating unit of the polyimide-polyamic acid copolymer to prepare a polyamic acid-imide copolymer varnish. Obtained.

(Synthesis Example 1-1-6)
To the NMP solution synthesized in Synthesis Example 1-1-1 above, 0.04 mol of 1-methylimidazole and 0.04 mol of N-Boc-imidazole are added per 1 mol of the repeating unit of the polyimide-polyamic acid copolymer. , to obtain a polyamic acid-imide copolymer varnish.

(Synthesis Example 2-1)
After purging a 500 ml four-necked flask with nitrogen, 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 nitrogen flow. After that, the polymerization reaction was carried out overnight at room temperature. Thereafter, the NMP was added to adjust the solid content to 12% by mass, thereby obtaining an NMP solution of polyamic acid (hereinafter also referred to as polyamic acid varnish). The polyamic acid thus obtained had a weight average molecular weight (Mw) of 63,353 and a number average molecular weight (Mn) of 29,472.

(Synthesis Example 2-2)
After purging a 500 ml four-necked flask with nitrogen, 31.68 mmol of 4-aminophenyl-4′-aminobenzoate (APAB), 7.92 mmol of 9,9-bis(aminophenyl)fluorene (BAFL) and 70 g of NMP were added. , the APAB and BAFL were completely dissolved with stirring. After visually confirming that APAB and BAFL were completely dissolved, 32.00 mmol of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4 -Dicarboxyphenyl)fluorene dianhydride (BPAF) (8.00 mmol) and NMP (22.29 g) were added, stirred at 80°C for 5 hours under nitrogen flow, and then polymerized overnight at room temperature. Thereafter, the NMP was added to adjust the solid content to 12% by mass, thereby obtaining an NMP solution of polyamic acid (hereinafter also referred to as polyamic acid varnish). The polyamic acid thus obtained had a weight average molecular weight (Mw) of 72,118 and a number average molecular weight (Mn) of 33,741.

(Synthesis Example 2-3)
A polyamic acid-imide copolymer varnish was synthesized in the same manner as in Example 1 of WO 2020/138360 pamphlet.

(Synthesis Example 2-4)
A polyimide varnish was synthesized in the same manner as in Example 1 of WO2019/188305.

The abbreviations of each component in the table below have the following meanings.
BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride ODPA: 4,4'-oxydiphthalic dianhydride BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorenedioic acid Anhydride TAHQ: p-phenylene bis(trimellitate anhydride)
BPF-PA: 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]
Fluorene dianhydride 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'-diaminodiphenyl sulfone 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

<Embodiment I>
The varnish obtained in each synthesis example was used as it was as a resin composition, and was evaluated according to the method described above. The synthesis results are shown in Table 1, and the evaluation results are shown in Tables 2-4.

As is clear from Tables 1 and 2, the polyimide film (Comparative Example 1-1) composed only of the structural unit N (polyamic acid) was excellent in residual stress, but had large YI and Haze values. Further, a polyimide film obtained from a polyamic acid synthesized with the same composition as the polyamic acid-imide copolymer described in Comparative Example 1-2 (the same molar ratio of the monomers constituting X ₁ to X ₄ ) was obtained by YI value and haze value are excellent, but the residual stress is increased and the performance is not sufficient for use as an optical display substrate.

Furthermore, the polyamide obtained by the method described in Example 1 of WO 2020/138360 pamphlet, which does not use general formula (A-1) or (A-2) as X ₂ in structural unit N The polyimide film (Comparative Example 1-3) obtained from the acid-imide copolymer was colored yellow in the 430° C. heat treatment step, and had large YI and Haze values. Further, a polyimide film (Comparative Example 1-4) obtained from the polyimide obtained by the method described in Example 1 of WO 2019/188305 pamphlet, which is composed of the structural unit M only (polyimide), is 430 Although the yellowing in the °C heat treatment process was suppressed, the residual stress was high and the performance was not sufficient for use as a substrate for optical displays.

On the other hand, it contains a structural unit represented by general formula (1) described in Examples 1-1 to 1-30 and a structure represented by general formula (A-1) or (A- ₂ ) as X2. , The polyimide film obtained from the polyamic acid-imide copolymer has a low yellowness (YI value) of 15 or less and a haze value (Haze value) of 0.5% or less, which is sufficient for use as a substrate for optical displays. had good performance. Moreover, the residual stress was as low as 25 MPa or less, and the mechanical properties were sufficient. From the above, it was confirmed that the polyimide resin film obtained from the resin composition according to the present invention is a resin film with low yellowness, low haze, and low residual stress.

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.

Also, as in Synthesis Example 1-1-2, a polyamic acid-imide copolymer varnish can be obtained by synthesizing polyamic acid and polyimide separately and then mixing and reacting them. The polyimide film obtained from this varnish had performance equivalent to that of Example 1-1-1, as shown in Example 1-1-2. This indicates that (c) polyamic acid-imide copolymer can be obtained by mixing and reacting (a) polyamic acid and (b) polyimide synthesized at a predetermined molar ratio.

In addition, in Table 2, the molar ratio of the structural unit N of the polyamic acid consisting of X ₁ and X ₂ and the structural unit M of the polyimide consisting of X ₃ and X ₄ (number of moles of structural unit N: number of moles of structural unit M) was 60:40, a transparent film with excellent yellowness and haze was obtained, the residual stress was as low as 25 MPa or less, and the mechanical properties were sufficient.

Also, in Table 2, as shown in Examples 1-6, 1-14, and 1-15, the ratio of X ₄ /X ₃ is 1.01 to 2 and the ratio of diamine to acid dianhydride. When is increased, the proportion of amines at the ends of polyimide increases, so that the reactivity of polyamic acid and polyimide improves when reacting with polyamic acid, and the polyimides are well dispersed when forming a film. , a transparent film excellent in yellowness (YI value) and haze (Haze value) is obtained. Moreover, as can be seen from Examples 1-6, 1-14, and 1-15, the yellowness index (YI value) of the composition having a ratio of X ₄ /X ₃ of 1.11 is low, and is particularly preferable.

Further, as shown in Examples 2-2 to 2-5 in Table 3, films obtained from polyimide-polyamic acid copolymers containing 1-methylimidazole or N-Boc-imidazole as an imidization catalyst has a low yellowness index (YI value) and can be suitably used as a substrate for displays.

Further, in Table 4, as shown in Comparative Example 2-1 (Synthesis Example 2-1), the polyimide film obtained from polyamic acid consisting only of the structural unit N has a high elastic modulus at 25 ° C. and 350 ° C. Even after reheating to 430° C. after Al sputtering, no swelling or breakage occurred, but the YI value was high and the performance as a substrate for optical displays was insufficient.

In Table 4, as shown in Comparative Example 2-2 (Synthesis Example 2-2), when the elastic modulus at 350°C is low, when reheating to 430°C after Al sputtering, swelling or tearing occurs. has occurred. This is thought to be because the content of the polyimide portion is large and the modulus of elasticity at high temperatures is low, so the difference in shrinkage force between Al and polyimide increases in the high temperature range of 350° C. or higher, resulting in tearing or swelling. be done.

On the other hand, when the elastic modulus at 350° C. is 0.5 GPa or more, even if there is a large difference in shrinkage force in the high temperature region, the strength of the film is high, so tearing or blistering does not occur, and it is suitable as a substrate for displays. can be used. Furthermore, as shown in Examples 3-1 to 3-3 in Table 4, the film has a high elastic modulus at 350 ° C. and a haze value (Haze value) of 0.5% or less and does not undergo phase separation. has a small rate of change in YI value in a 430° C. reheating test, and can be suitably used as a substrate for displays.

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.

(Synthesis Example 1-31)
Synthesis Example 1-1-1 was repeated 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 polyamic acid-imide copolymer was 173,000.

(Synthesis Example 1-32)
Synthesis Example 1-1-1 was repeated 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 resulting polyamic acid-imide copolymer was 171,000.

(Synthesis Example 1-33)
Synthesis Example 1-1-1 was repeated except that the amount of APAB in Synthesis Example 1-1-1 was changed to 83.45 mmol. The polyamic acid-imide copolymer thus obtained had a weight average molecular weight (Mw) of 224,000.

(Synthesis Example 1-34)
The procedure was carried out in the same manner as in Synthesis Example 1-1-1 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 polyamic acid-imide copolymer was 221,000.

(Synthesis Example 3-1)
N-methyl-2-pyrrolidone (NMP) (water content: 250 ppm by mass) immediately after opening the 18L can was added to a nitrogen-substituted 5L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. 180.77 g (800 mmol) of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) was added and stirred to dissolve APAB. After that, 235.38 g (792 mmol) of biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) was added, and the mixture was heated at 70° C. under nitrogen flow. A polymerization reaction was carried out with stirring for 5 hours. Then, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 152,000.

(Synthesis Example 3-2)
N-Methyl-2-pyrrolidone (NMP) (water content: 250 mass ppm) immediately after opening the 18L can was added to a nitrogen-substituted 5L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. 181.69 g (800 mmol) of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) was added and stirred to dissolve APAB. After that, 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 the mixture was heated at 70° C. under nitrogen flow. A polymerization reaction was carried out with stirring for 5 hours. After that, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 175,000.

(Synthesis Example 3-3)
N-methyl-2-pyrrolidone (NMP) (water content: 250 ppm by mass) immediately after opening the 18L can was added to a nitrogen-substituted 5L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) 145.35 g (637 mmol) and 4,4'-diaminodiphenyl sulfone (4,4'-DAS, purity 99.5%) , Seika Co., Ltd.) was added and stirred to dissolve APAB and 4,4′-DAS. After that, 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 the mixture was heated at 70° C. under nitrogen flow. A polymerization reaction was carried out with stirring for 5 hours. After that, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 173,000.

(Synthesis Example 3-4)
N-Methyl-2-pyrrolidone (NMP) (water content: 250 mass ppm) immediately after opening the 18L can was added to a nitrogen-substituted 5L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. 181.69 g (800 mmol) of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) was added and stirred to dissolve APAB. After that, 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 the mixture was heated at 70° C. under nitrogen flow. A polymerization reaction was carried out with stirring for 5 hours. After that, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 242,000.

(Synthesis Example 3-5)
N-Methyl-2-pyrrolidone (NMP) (water content: 250 mass ppm) immediately after opening the 18L can was added to a nitrogen-substituted 5L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. 182.42 g (800 mmol) of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) was added and stirred to dissolve APAB. After that, 235.38 g (799 mmol) of biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manac Co., Ltd.) was added, and the mixture was heated at 70° C. under nitrogen flow. A polymerization reaction was carried out with stirring for 5 hours. After that, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 241,000.

(Synthesis Example 3-6)
N-methyl-2-pyrrolidone (NMP) (water content: 250 mass ppm) immediately after opening the 18L can was placed in a nitrogen-substituted 1L separable flask, and an amount corresponding to a solid content of 25wt% was added, and 4-aminophenyl was added. 80 mmol of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Yakuhin Co., Ltd.) was added and stirred to dissolve APAB. Then, bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid) 2,2′,3,3′,5,5′-hexamethylbiphenyl-4,4′-diyl (Honshu (manufactured by Kagaku Kogyo Co., Ltd.) was added, and a polymerization reaction was carried out with stirring at 70° C. for 5 hours under nitrogen flow. After that, it was cooled to room temperature and allowed to stand under nitrogen flow for 8 days. By adding the NMP and adjusting the solution viscosity to 10,000 mPa·s, an NMP solution of polyamic acid (hereinafter also referred to as varnish) was obtained. The weight average molecular weight (Mw) of the obtained polyamic acid was 172,000.

(Reference example 4-1)
Using the NMP solution of the polyimide-polyamic acid copolymer (hereinafter also referred to as PAI) synthesized in Synthesis Example 1-1-1, the IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 6.

(Example 4-1)
Using the NMP solution of the polyimide-polyamic acid copolymer synthesized in Synthesis Example 1-32, imidization catalyst 1 (1-methylimidazole ) was added and stirred at room temperature for 24 hours to obtain a polyamic acid-imide copolymer varnish. Using this varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 6.

(Examples 4-2 to 30)
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 otherwise Example 4-1 Polyamic acid-imide copolymer varnish was obtained in the same manner as above. Using the obtained varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 6.

(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 the aproton having a boiling point of 250 to 350 ° C. was added. A polyamic acid-imide copolymer varnish was obtained in the same manner as in Example 4-1 except that 20 parts by mass of sulfolane as a polar substance was added to 100 parts by mass of NMP. Using the obtained varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 6.

(Comparative Example 5-1)
Using the NMP solution of the polyamic acid (hereinafter also referred to as PAA) synthesized in Synthesis Example 3-1, the IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 7.

(Example 5-1)
Using the NMP solution of polyamic acid synthesized in Synthesis Example 3-2, 1 part by weight of imidization catalyst 1 (1-methylimidazole) described in Table 5 is added to 100 parts by weight of polyamic acid copolymer, Stirring was performed at room temperature for 24 hours to obtain a polyamic acid varnish. Using this varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 7.

(Examples 5-2 to 29, Comparative Example 5-2)
Using the NMP solution of the polyamic acid described in Table 7, the imidization catalyst described in Table 5 was added in the amount described in Table 7, and otherwise the polyamide was prepared in the same manner as in Example 5-1. An acid varnish was obtained. Using the obtained varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 7.

(Example 5-30)
Using the polyamic acid NMP solution described in Table 7, the imidization catalyst described in Table 5 was added in the amount described in Table 7, and sulfolane was added as an aprotic polar substance having a boiling point of 250 to 350 ° C. was added in an amount of 20 parts by mass based on 100 parts by mass of NMP, and a polyamic acid varnish was obtained in the same manner as in Example 5-1. Using the obtained varnish, the above IR cure defect evaluation and degassing evaluation were performed. The results are listed in Table 7.

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

As is clear from Tables 8 and 9, the polyimide film (Comparative Example II-1-1) composed only of the structural unit N (polyamic acid) has excellent residual stress, but the YI value and Haze value are large. . Further, a polyimide film obtained from a polyamic acid synthesized with the same composition as the polyamic acid-imide copolymer described in Example II-1-1 (the same molar ratio of the monomers constituting X ₁ to X ₄ ) is , YI value, and Haze value are excellent, but the residual stress becomes large, and both of them do not exhibit sufficient performance for use as substrates for optical displays.

Furthermore, as X ₂ in structural unit N, general formula (A-1) or (A-2) is not used, obtained by the method described in Example 1 described in WO 2020/138360 pamphlet The polyimide film obtained from the polyamic acid-imide copolymer (Comparative Example II-1-3) was colored yellow in the 430° C. heat treatment step, and had large YI and Haze values. Further, a polyimide film obtained from the polyimide obtained by the method described in Example 1 described in WO 2019/188305, which is composed of the structural unit M only (polyimide) (Comparative Example II-1-4 ) suppressed yellowing in the 430° C. heat treatment process, but had high residual stress and did not have sufficient performance to be used as a substrate for optical displays.

On the other hand, as in Example II-1-1-1, as X ₃ , the structure represented by the general formula (A-1) and the structure derived from 4,4'-oxydiphthalic dianhydride (ODPA) , and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) containing at least one selected from the group consisting of structures derived from polyamic acid - polyimide film obtained from an imide copolymer, The yellowness index (YI value) was as low as 15 or less, and the haze value (Haze value) was 0.5% or less, and had sufficient performance to be used as a substrate for optical displays. Moreover, the residual stress was as low as 25 MPa or less, the bending resistance was excellent, and the mechanical properties were sufficient. From the above, it was confirmed that the polyimide resin film obtained from the resin composition according to the present invention is a resin film with low yellowness, low haze, and low residual stress.

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.

Also, as in Synthesis Example 1-1-2, a polyamic acid-imide copolymer varnish can be obtained by synthesizing polyamic acid and polyimide separately and then mixing and reacting them. A polyimide film obtained from this varnish had performance equivalent to that of Example II-1-1-1, as shown in Example II-1-1-2. This indicates that (c) polyamic acid-imide copolymer can be obtained by mixing and reacting (b) polyamic acid and (a) polyimide synthesized at a predetermined molar ratio.

On the other hand, as shown in Comparative Example II-1-1 in Table 9, the polyimide film obtained from the polyamic acid having only the structural unit N had excellent residual stress but insufficient bending resistance. This is probably because the polyimide film composed only of the structural unit N is very rigid, so that in-plane crystallization progressed during the bending test, resulting in scratches. Therefore, the polyimide copolymer film obtained from the polyamic acid-imide copolymer composed of the structural units N and M has excellent yellowness and haze, low residual stress, and excellent bending resistance.

Also, as shown in Examples II-1-6, II-1-12, and II-1-13, the X ₄ /X ₃ ratio is 1.01 to 2 and the diamine relative to the dianhydride When the ratio of is increased, the proportion of amines at the ends of the polyimide increases, which improves the reactivity of polyamic acid and polyimide when reacting with polyamic acid, and the polyimides are well dispersed when forming a film. Therefore, a transparent film having excellent yellowness (YI value) and haze (Haze value) and excellent folding resistance can be obtained. In addition, as can be seen from Examples II-1-6, II-1-12, and II-1-13, the yellowness (YI value) of the composition where the ratio of X ₄ /X ₃ is 1.11 is low. , is particularly preferred.

Further, in Table 10, as shown in Examples II-2-1 to II-2-5, polyimide-polyamic acid copolymer containing 1-methylimidazole or N-Boc-imidazole as an imidization catalyst The film obtained from has a low yellowness index (YI value) and can be suitably used as a substrate for displays.

<Embodiment III>
[Example III-1]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 15 wt%. 15.69 g (49.0 mmol) of 2′-bis(trifluoromethyl)benzidine (TFMB) was added and stirred to dissolve TFMB. After that, 9.27 g (42.5 mmol) of pyromellitic dianhydride (PMDA) and 3.33 g (7.5 mmol) of 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) In addition, the solution was stirred under nitrogen flow at 80°C for 4 hours, cooled to room temperature, and then sulfolane (mass of solvent + mass of sulfolane) was adjusted to 3% by weight as 100% by weight as an aprotic polar substance with a boiling point of 250°C to 350°C. and further stirred for 1 hour to obtain a polyamic acid solution (hereinafter also referred to as varnish).

This varnish is 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, placed in a furnace and heated at 380° C. for 1 hour under nitrogen flow. After curing, a polyimide resin film was obtained. For the polyimide resin film formed on the silicon wafer, measure the film thickness at 39 points in the plane using Lambda Ace, and average [(film thickness that deviates most from the average value) - (average film thickness)] The value divided by the film thickness (hereinafter also referred to as in-plane film thickness uniformity) was 6.0%.

When the YI of the polyimide resin film formed on the eagle glass was measured using a haze meter, it was 7.9 in terms of film thickness of 10 μm.
Further, when the polyimide resin film formed on the eagle glass was reheated to 400° C. and the gas components generated were analyzed by GCMS, sulfolane was not detected.

[Example III-2]
A polyamic acid solution was obtained in the same manner as in Example III-1, except that the amount of sulfolane added was changed from 3 wt % to 20 wt %. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-3]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 15 wt%. 15.69 g (49.0 mmol) of 2′-bis(trifluoromethyl)benzidine (TFMB) was added and stirred to dissolve TFMB. After that, 9.27 g (42.5 mmol) of pyromellitic dianhydride (PMDA) and 3.33 g (7.5 mmol) of 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) The mixture was stirred at 80° C. for 4 hours under nitrogen flow, cooled to room temperature, and added dropwise to 6 times the volume of water with stirring to precipitate a polymer. After the polymer was separated by filtration, it was vacuum-dried at 40° C. for 24 hours using a vacuum dryer. The polymer was then dissolved in sulfolane to 15 wt % to obtain a polyamic acid solution. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-1]
A polyamic acid solution was obtained in the same manner as in Example III-1, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-4]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that sulfolane was changed to 3-methylsulfolane. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-5]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that benzophenone was used instead of sulfolane. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-6]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that sulfolane was changed to 2-phenoxyethyl acetate. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-7]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that diphenyl carbonate was used instead of sulfolane. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-8]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that sulfolane was changed to adipoamide. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-9]
A polyamic acid solution was obtained in the same manner as in Example III-2 except that sulfolane was changed to adiponitrile. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-10]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that dibutyl sulfoxide was used instead of sulfolane. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-2]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that dimethylsulfone was used instead of sulfolane. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-3]
A polyamic acid solution was obtained in the same manner as in Example III-2, except that sulfolane was changed to diphenylsulfone. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-11]
A 500 ml separable flask is replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can as a solvent is added to the separable flask in an amount equivalent to a solid content of 20 wt%. 8.95 g (39.2 mmol) of 4-aminophenyl aminobenzoate (APAB) and 2.43 g (9.8 mmol) of 4,4′-diaminophenyl sulfone (4,4′-DAS) were added and stirred. Both were dissolved. Then, 14.71 g (50 mmol) of 4,4′-biphthalic dianhydride (BPDA) was added, stirred under nitrogen flow at 80° C. for 4 hours, cooled to room temperature, and then sulfolane was removed (mass of solvent + mass of sulfolane ) was added to 100 wt.
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-4]
A polyamic acid solution was obtained in the same manner as in Example III-11 except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-12]
A 500 ml separable flask was purged with nitrogen, and 22.2 g of N-methylpyrrolidone (NMP: moisture content: 250 ppm) was added as a solvent to the separable flask immediately after opening the 18 L can. 3′-DAS) was added and dissolved with stirring, 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 attached to the flask, and under nitrogen flow, the reaction was carried out at 180° C. for 2 hours while removing generated water from the Dean-Stark tube, and then heated at 180° C. for 1 hour. The Stark tube was drained of all added toluene. After that, the reaction solution was cooled to room temperature, and 81.96 g of N-methylpyrrolidone (NMP: water content: 250 ppm) and 11.77 g (BPDA) of 4,4'-biphthalic dianhydride (BPDA) immediately after opening the 18 L can were used as solvents. 40 mmol) and 8.72 g (38.2 mmol) of 4-aminophenyl 4-aminobenzoate (APAB) were added and dissolved by stirring. Then, under nitrogen flow, react at 80° C. for 4 hours, cool to room temperature, add sulfolane (mass of solvent + mass of sulfolane) to 20 wt %, and stir for an additional hour. A polyamic acid-soluble polyimide solution (hereinafter also referred to as varnish) was obtained.
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-5]
A polyamic acid-soluble polyimide solution was obtained in the same manner as in Example III-12, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-13]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 20 wt%, 9, 17.07 g (49 mmol) of 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)fluoric acid dianhydride (BPAF) was added, stirred under nitrogen flow at 80° C. for 4 hours, cooled to room temperature, and then sulfolane was added. (mass of solvent + mass of sulfolane) was added so as to be 20 wt% with 100 wt%, and further stirred for 1 hour to obtain a polyamic acid solution (hereinafter also referred to as varnish).
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-6]
A polyamideimide solution was obtained in the same manner as in Example III-13, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-14]
A 300 ml separable flask was purged with nitrogen, dimethylacetamide (DMAc) as a solvent was put into the separable flask in an amount corresponding to a solid content of 26 wt %, and 4,4'-diaminobenzanilide (DABAN) was added to the flask. 27 g (10 mmol) was added and stirred to dissolve DABAN. Then, 3.84 g (10 mmol) of norbornane-2-spiro-α-cyclopentanone-α'-spiro-2'-norbornane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) In addition, after stirring at room temperature for 12 hours under nitrogen flow, 3-methylsulfolane (mass of solvent + mass of 3-methylsulfolane) was added to 100 wt% to make 20 wt%, and further stirred for 1 hour to obtain a polyamic acid. (hereinafter also referred to as varnish) was obtained.
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-7]
A polyamic acid solution was obtained in the same manner as in Example III-14, except that 3-methylsulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-15]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 15 wt%. 5.6 g (49 mmol) of 4-cyclohexanediamine (1,4-CHDA) was added and dissolved by stirring. After that, 13.8 g (47.5 mmol) of 4,4′-biphthalic dianhydride (BPDA) and 0.7 g (1.5 mmol) of p-phenylenebistrimellitic dianhydride (TMHQ) were added, followed by nitrogen flow. After stirring at 80° C. for 1 hour and at room temperature for 5 hours, sulfolane (mass of solvent + mass of sulfolane) was added to 100 wt % to make 20 wt %. , also called varnish).
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-16]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 15 wt%. 5.6 g (49 mmol) of 4-cyclohexanediamine (1,4-CHDA) was added and dissolved by stirring. After that, 13.8 g (47.5 mmol) of 4,4′-biphthalic dianhydride (BPDA) and 0.7 g (1.5 mmol) of p-phenylenebistrimellitic dianhydride (TMHQ) were added, followed by nitrogen flow. After stirring at 80° C. for 1 hour and at room temperature for 5 hours, this solution was added dropwise to 6 times the volume of water with stirring to precipitate a polymer. After the polymer was separated by filtration, it was vacuum-dried at 40° C. for 24 hours using a vacuum dryer. The polymer was then dissolved in sulfolane to 15 wt % to obtain a polyamic acid solution. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-8]
A polyamic acid solution was obtained in the same manner as in Example III-15, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-17]
168 g of γ-butyrolactone (GBL) was placed in a 500 ml separable flask, 15.2 g (100 mmol) of 3,5-diaminobenzoic acid (DABA) was added and dissolved with stirring, and then norbornane-2-spiro-α-cyclopenta. 38.4 g (100 mmol) of non-α'-spiro-2'-norbornane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were attached to the flask, and under nitrogen flow, the reaction was carried out at 180° C. for 2 hours while removing generated water from the Dean-Stark tube, and then heated at 180° C. for 1 hour. The Stark tube was drained of all added toluene. Sulfolane was added so as to be 20 wt % when (mass of solvent + mass of sulfolane) was 100 wt %, and the mixture was further stirred for 1 hour to obtain a soluble polyimide solution (hereinafter also referred to as varnish).
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-18]
A polyamic acid solution was obtained in the same manner as in Example III-17, except that the amount of sulfolane added was changed from 20 wt % to 50 wt %. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-9]
168 g of γ-butyrolactone (GBL) was placed in a 500 ml separable flask, 15.2 g (100 mmol) of 3,5-diaminobenzoic acid (DABA) was added and dissolved with stirring, and then norbornane-2-spiro-α-cyclopenta. 38.4 g (100 mmol) of non-α'-spiro-2'-norbornane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were attached to the flask, and under nitrogen flow, the reaction was carried out at 180° C. for 2 hours while removing generated water from the Dean-Stark tube, and then heated at 180° C. for 1 hour. The Stark tube was drained of all added toluene. Thereafter, this solution was added dropwise to 6 times the volume of water while stirring to precipitate a polymer. After the polymer was separated by filtration, it was vacuum-dried at 40° C. for 24 hours using a vacuum dryer. The polymer was then dissolved in sulfolane to 15 wt% to obtain a soluble polyimide solution. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-10]
A polyamic acid solution was obtained in the same manner as in Example III-17, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-19]
130 g of N-methylpyrrolidone (NMP: water content 250 ppm) was put into a 500 ml separable flask, and 32.858 g (97.7 mmol) of 2,2′-bis(trifluoromethyl)-4,4′-diaminodiphenyl ether (6FODA) was added. ) was added and dissolved with stirring, and then norbornane-2-spiro-α-cyclopentanone-α'-spiro-2'-norbornane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) 22.936 g (60 mmol) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were attached to the flask, and under nitrogen flow, the reaction was carried out at 180° C. for 2 hours while removing generated water from the Dean-Stark tube, and then heated at 180° C. for 1 hour. The Stark tube was drained of all added toluene. After cooling this solution to 50 ° C., add 25 g of NMP, add 11.704 g (40 mmol) of 4,4'-biphthalic dianhydride (BPDA), stir at 50 ° C. for 4 hours, cool to room temperature, further Shin-Etsu 7.723 g (2 mmol) of Silicone Diamine X-22-1660-B-3 manufactured by Kagaku was added and stirred for 1 hour. Then, sulfolane was added so as to make 20 wt% (mass of solvent + mass of sulfolane) 100 wt%, and further stirred for 1 hour to obtain a polyamic acid-soluble polyimide solution (hereinafter also referred to as varnish).
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-20]
130 g of N-methylpyrrolidone (NMP: water content 250 ppm) was put into a 500 ml separable flask, and 32.858 g (97.7 mmol) of 2,2′-bis(trifluoromethyl)-4,4′-diaminodiphenyl ether (6FODA) was added. ) was added and dissolved with stirring, and then norbornane-2-spiro-α-cyclopentanone-α'-spiro-2'-norbornane-5,5',6,6'-tetracarboxylic dianhydride (CpODA) 22.936 g (60 mmol) and 30 g of toluene were added. A reflux tube and a Dean-Stark tube were attached to the flask, and under nitrogen flow, the reaction was carried out at 180° C. for 2 hours while removing generated water from the Dean-Stark tube, and then heated at 180° C. for 1 hour. The Stark tube was drained of all added toluene. After cooling this solution to 50 ° C., add 25 g of NMP, add 11.704 g (40 mmol) of 4,4'-biphthalic dianhydride (BPDA), stir at 50 ° C. for 4 hours, cool to room temperature, further Shin-Etsu 7.723 g (2 mmol) of Silicone Diamine X-22-1660-B-3 manufactured by Kagaku was added and stirred for 1 hour. Thereafter, this solution was added dropwise to 6 times the volume of water while stirring to precipitate a polymer. After the polymer was separated by filtration, it was vacuum-dried at 40° C. for 24 hours using a vacuum dryer. The polymer was then dissolved in sulfolane to 15 wt % to obtain a polyamic acid-soluble polyimide solution. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-11]
A polyamic acid-soluble polyimide solution was obtained in the same manner as in Example III-19, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Example III-21]
A 500 ml separable flask was replaced with nitrogen, and N-methylpyrrolidone (NMP: water content 250 ppm) immediately after opening the 18 L can was added as a solvent to the separable flask in an amount corresponding to a solid content of 15 wt%. 3.4576 g (30.3 mmol) of 4-cyclohexanediamine (1,4-CHDA) and 26.0326 g (70.7 mmol) of 4,4'-bis(aminophenoxy)biphenyl (BAPB) were added and dissolved by stirring. let me After that, 30.5098 g (100.9 mmol) of decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride (DNDA) was added, and the mixture was stirred at room temperature under nitrogen flow. After stirring overnight, sulfolane (mass of solvent + mass of sulfolane) was added to 20 wt% with 100 wt%, and further stirred for 1 hour to obtain a polyamic acid solution (hereinafter also referred to as varnish).
This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.

[Comparative Example III-12]
A polyamic acid-soluble polyimide solution was obtained in the same manner as in Example III-21, except that sulfolane was not added. This varnish was cured in the same manner as in Example III-1, and the in-plane film thickness uniformity of the polyimide resin film, YI, and the amount of degassing during reheating were measured. Met.
Tables 11 to 13 collectively show the results of the above Examples and Comparative Examples.

As described above, the resin compositions of the examples are softer and more fluid than the comparative examples, and when formed into a polyimide resin film, the in-plane uniformity of the film thickness is improved. , and YI were also reduced, and the properties required for display applications were excellent.

2a lower substrate 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 partition wall (bank)
252 lower electrode (anode)
253 hole transport layer 254 light emitting layer 255 upper electrode (cathode)
256 TFTs
257 contact hole 258 interlayer insulating film 259 lower electrode 261 hollow portion

Claims

The following general formula (1):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n, m, and l are positive integers, and As X 2 in general formula (1), the following general formula (A-1):

(wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid-imide copolymer containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, and the (e) imidization catalyst is an imidazole compound, a pyridine compound, and A resin composition comprising at least one selected from the group consisting of tertiary amine compounds.
The imidazole compound is 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 is at least one selected from the group consisting of
The pyridine compound is at least one selected from the group consisting of 4-dimethylaminopyridine, 2,2'-bipyridyl, nicotinic acid, isoquinoline, pyridine, and 2-methylpyridine, and/or the tertiary amine The 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 is one
The resin composition according to claim 1.
The resin composition according to claim 1 or 2, wherein the (e) imidization catalyst is the imidazole compound.
The resin composition according to any one of claims 1 to 3, wherein the content of (e) the imidization catalyst is 5 parts by mass or more with respect to 100 parts by mass of the polyamic acid-imide copolymer.
The following general formula (1):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n, m, and l are positive integers, and As X 2 in general formula (1), the following general formula (A-1):

(wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
and (d) an organic solvent, wherein the polyamic acid-imide copolymer has a weight average molecular weight of 170,000 or more.
The resin composition according to any one of claims 1 to 4, wherein the polyamic acid-imide copolymer has a weight average molecular weight of 170,000 or more.
The following general formula (3):

{Wherein, X 1 represents a tetravalent organic group, X 2 represents a divalent organic group, n is a positive integer, and X 2 in the general formula (3) , the following general formula (A-1):

(wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
(d) an organic solvent and (e) an imidization catalyst, wherein the (e) imidization catalyst is 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-un Decylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1H-imidazole, 4-dimethylaminopyridine, 2,2'-bipyridyl, nicotinic acid, isoquinoline, pyridine, 2-methylpyridine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1,4-diazabicyclo[2.2.2]octane, N-methylmorpholine, and at least one selected from the group consisting of triethylamine , resin composition.
The following general formula (3):

{Wherein, X 1 represents a tetravalent organic group, X 2 represents a divalent organic group, n is a positive integer, and X 2 in the general formula (3) , the following general formula (A-1):

(wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, wherein the (e) imidization catalyst is an imidazole compound, and the (e) imidization catalyst content is 5 parts by mass or more with respect to 100 parts by mass of the polyamic acid.
The following general formula (3):

{Wherein, X 1 represents a tetravalent organic group, X 2 represents a divalent organic group, n is a positive integer, and X 2 in the general formula (3) , the following general formula (A-1):

(wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; and * indicates a joint)
including the structure indicated by}
A polyamic acid containing a structural unit represented by, (d) an organic solvent, and (e) an imidization catalyst, wherein the (e) imidization catalyst is an imidazole compound, and the weight average molecular weight of the polyamic acid is 170,000 or more, the resin composition.
The resin composition according to claim 7 or 8, wherein the polyamic acid has a weight average molecular weight of 170,000 or more.
The content of the (e) imidization catalyst is 10 parts by mass or more with respect to 100 parts by mass of the polyamic acid-imide copolymer or 100 parts by mass of the polyamic acid, any one of claims 1 to 10. The resin composition according to .
The imidization catalyst (e) is an imidazole compound containing N-tert-butoxycarbonylimidazole (N-Boc-imidazole) and/or 1-methylimidazole, according to any one of claims 1 to 11. Resin composition.
The resin composition according to any one of claims 1 to 12, wherein the polyamic acid-imide copolymer or the polyamic acid has a weight average molecular weight of 220,000 or more.
The resin composition according to any one of claims 1 to 13, further comprising an aprotic polar substance having a boiling point of 250°C to 350°C.
The resin composition according to claim 14, wherein the aprotic polar substance is sulfolane.
X 4 in the general formula (1) or X 2 in (3) is represented by the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R 8 to R 11 each independently represent 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 indicates the linking group and * indicates the linking point}

{wherein R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a joint}

{wherein R 14 and R 15 each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and o each independently represent an integer of 0 to 4; * indicates a joint}
The resin composition according to any one of claims 1 to 15, which is at least one selected from the group consisting of structures represented by
X 3 in the general formula (1) is represented by the following general formula (A-3):

{wherein R 4 to R 7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; 1 indicates a linking group and * indicates a linking point}
A structure derived from 4,4′-oxydiphthalic dianhydride (ODPA), a structure derived from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), biphenyltetracarboxylic acid di It is at least one selected from the group consisting of a structure derived from anhydride (BPDA) and a structure derived from 4,4′-biphenylbis(trimellitic acid monoester acid anhydride) (TAHQ), claims 1- 6, The resin composition according to any one of 11 to 16.
Claims 1 to 6 and 11 to 17, wherein the content of the imidization catalyst (e) is in the range of 0.02 to 0.15 mol% relative to 1 mol of the repeating unit of the polyamic acid-imide copolymerization. The resin composition according to any one of.
The following general formula (1):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n, m, and l are positive integers, and X 1 and X 2 is called structural unit N, and the structural unit made up of X 3 and X 4 is called structural unit M,
When X 2 is a group derived from 4-amino-3-fluorophenyl-4-aminobenzoate, the following structures 1 and 2:
1. When X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X 2 is 4,4′-diaminodiphenyl sulfone and/or 2 , 2′-bis(trifluoromethyl)benzidine; X 3 is a group derived from norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride ;
except for}
and the following general formula (A-1) as X 2 :

{wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; * indicates a joint}
Or the following general formula (A-2):

{In the formula, 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. * indicates a joint}
Polyamic acid-imide copolymer characterized by having a structure represented by.
X 3 in the general formula (1) is represented by the following general formula (A-3):

{wherein R 4 to R 7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; 1 indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of Polyamic acid-imide copolymer according to claim 19, which is at least one of
X 4 in the general formula (1) is the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R 8 to R 11 each independently represent 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 indicates the linking group and * indicates the linking point}

{wherein R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a bond, provided that when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A- 5) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R 14 and R 15 each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and o each independently represent an integer of 0 to 4; * indicates a joint}
Polyamic acid-imide copolymer according to claim 19 or 20, which is at least one selected from the group consisting of structures represented by
The following general formula (1):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n, m, and l are positive integers, and X 1 and X 2 is called structural unit N, the structural unit made up of X 3 and X 4 is called structural unit M, and X 4 is 4,4′-diaminodiphenyl sulfone and/or excluding groups derived from 2,2′-bis(trifluoromethyl)benzidine}
and as X 3 , the following general formula (A-3):

{wherein R 4 to R 7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; 1 indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of Polyamic acid-imide copolymer characterized by comprising at least one of
X 4 in the general formula (1) is represented by the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R 8 to R 11 each independently represent 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 indicates the linking group and * indicates the linking point}

{wherein R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; i and j each independently represent an integer of 0 to 4; * indicates a bond, provided that when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A- 5) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R 14 and R 15 each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and o each independently represent an integer of 0 to 4; * indicates a joint}
Polyamic acid-imide copolymer according to claim 22, which is at least one selected from the group consisting of structures represented by
The diamine component constituting X 2 and the diamine component constituting X 4 in the general formula (1) are different in either diamine composition or diamine species, according to any one of claims 19 to 23. polyamic acid-imide copolymer.
X 1 in the general formula (1) is a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and 4,4'-biphenyl At least one selected from the group consisting of structures derived from bis (trimellitic acid monoester acid anhydride) (TAHQ), the polyamic acid-imide copolymer according to any one of claims 19 to 24 .
The molar ratio (X 2 /X 1 ) of X 1 and X 2 contained in the general formula (1) is 0.84 to 1.00, and X 3 and X contained in the general formula (1) Polyamic acid-imide copolymer according to any one of claims 19 to 25, wherein the molar ratio of 4 (X 4 /X 3 ) is from 1.01 to 2.00.
The molar ratio of the polyamic acid structural unit N composed of X 1 and X 2 and the polyimide structural unit M composed of X 3 and X 4 in the general formula (1) (number of moles of structural unit N: structure The polyamic acid-imide copolymer according to any one of claims 19 to 26, wherein the number of moles of units M) is in the range of 60:40 to 95:5.
A resin composition containing the polyamic acid-imide copolymer according to any one of claims 19 to 27 and (d) an organic solvent.
29. The resin composition according to claim 28, wherein the ratio of the polyamic acid structural unit N composed of X 1 and X 2 is 60 to 95 mol % in the total polymer contained in the resin composition.
The resin composition according to claim 28 or 29, further comprising (e) an imidization catalyst.
The following general formula (2):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n and m are positive integers, and X 1 and X 2 is called structural unit N, and the structural unit made up of X 3 and X 4 is called structural unit M, and X 2 is 4-amino-3-fluorophenyl-4-aminobenzoate If it is a group derived from, the following structures 1 and 2:
1. When X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), X 2 is 4,4′-diaminodiphenyl sulfone and/or 2 , 2′-bis(trifluoromethyl)benzidine; and 2. X 3 is a group derived from norbornane-2-spiro-α-cyclopentanone a-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride be;
except for}
and the following general formula (A-1) as X 2 :

{wherein R 1 and R 2 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; a and b each independently represent an integer of 0 to 4; * indicates a joint}
Or the following general formula (A-2):

{Wherein, R 3 represents a monovalent organic group having 1 to 20 carbon atoms or halogen, c is an integer of 0 to 4, and * indicates a bond}
Polyimide copolymer characterized by having a structure represented by.
X 3 in the above general formula (2) is represented by the following general formula (A-3):

{wherein R 4 to R 7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; 1 indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of 32. The polyimide copolymer of claim 31, which is at least one of
The following general formula (2):

{Wherein, X 1 and X 3 represent a tetravalent organic group, X 2 and X 4 represent a divalent organic group, n and m are positive integers, and X 1 and X 2 A structural unit composed of is called structural unit N, a structural unit composed of X 3 and X 4 is called structural unit M, and X 4 is 4,4′-diaminodiphenylsulfone, 2,2′- excluding groups derived from bis(trifluoromethyl)benzidine}
and as X 3 , the following general formula (A-3):

{wherein R 4 to R 7 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; d to g each independently represent an integer of 0 to 4; 1 indicates a linking group and * indicates a linking point}
structure represented by, 4,4'-oxydiphthalic dianhydride (ODPA)-derived structure, and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-derived structure selected from the group consisting of A polyimide copolymer comprising at least one of
X 4 in the general formula (2) is the following general formula (A-4), the following general formula (A-5) and the following general formula (A-6):

{wherein R 8 to R 11 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen, and h to k each independently represent an integer of 0 to 4, Z 2 indicates the linking group and * indicates the linking point}

{wherein R 12 and R 13 each independently represent a monovalent organic group having 1 to 20 carbon atoms or halogen; l and m each independently represent an integer of 0 to 4; * indicates a bond, and when X 3 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), the general formula (A-5 ) is a group derived from 4,4′-diaminodiphenylsulfone}

{wherein R 14 and R 15 each independently represents a monovalent organic group having 1 to 20 carbon atoms or halogen; n and о each independently represent an integer of 0 to 4; * indicates a joint}
The polyimide copolymer according to claim 33, which is at least one selected from the group consisting of structures represented by:
X 1 in the general formula (2) is a structure derived from biphenyltetracarboxylic dianhydride (BPDA), a structure derived from 4,4'-oxydiphthalic dianhydride (ODPA), and 4,4'-biphenyl At least one selected from the group consisting of structures derived from bis (trimellitic monoester acid anhydride) (TAHQ), the polyimide copolymer according to any one of claims 31 to 34.
The molar ratio (X 2 /X 1 ) of X 1 and X 2 contained in the general formula (2) is 0.84 to 1.00, and X 3 and X contained in the general formula (2) The polyimide copolymer according to any one of claims 31 to 35, wherein the molar ratio of 4 (X 4 /X 3 ) is from 1.01 to 2.00.
The molar ratio of the polyimide structural unit N composed of X 1 and X 2 and the polyimide structural unit M composed of X 3 and X 4 in the general formula (2) (number of moles of structural unit N: number of structural units M number of moles) is in the range of 60:40 to 95:5.
Having 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),
A resin composition comprising an aprotic polar substance having a boiling point of 250° C. to 350° C.:

{wherein P 1 represents a divalent organic group, P 2 represents a tetravalent organic group, and p represents a positive integer}

{wherein P 1 represents a divalent organic group, P 2 represents a tetravalent organic group, and p represents a positive integer}.
A resin composition containing a polyimide represented by the following general formula (II), a solvent, and an aprotic polar substance having a boiling point of 250° C. to 350° C.:

{wherein P 1 represents a divalent organic group, P 2 represents a tetravalent organic group, and p represents a positive integer}.