Polyimide precursor resin composition

Abstract

To provide a polyimide precursor which is excellent in coating characteristics and productivity of slit coating and is also excellent in optical characteristics required for application of a flexible substrate, and a resin composition of the same.SOLUTION: A polyimide precursor contains a structural unit derived from a fluorene skeleton and a silicon-containing structural unit, and has a weight average molecular weight of 90,000-250,000.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polyimide precursor and a resin composition thereof, and further discloses a polyimide film and a method for producing the same, a laminate and a method for producing the same, and a display substrate and a method for producing the same. [Background technology]

[0002] Polyimide resins are insoluble, infusible, and extremely heat-resistant resins that have excellent properties such as thermal oxidation resistance, heat resistance, radiation resistance, low temperature resistance, and chemical resistance, and are therefore used in a wide range of fields, including electronic materials. Examples of applications of polyimide resin in the electronic materials field include insulating coating materials, insulating films, semiconductors, electrode protection films for TFT-LCDs, etc. Recently, in the field of display materials, polyimide resin is being considered for use as a flexible substrate, taking advantage of its lightness and flexibility, in place of the glass substrates that have traditionally been used.

[0003] For example, Patent Document 1 discloses a resin precursor (weight average molecular weight: 30,000 to 90,000) polymerized from bis(diaminodiphenyl)sulfone and having a siloxane unit, and also discloses that a polyimide obtained by curing the resin precursor has low residual stress between the support such as glass, excellent chemical resistance, and small effect of oxygen concentration during the curing process on the YI value and total light transmittance. Patent Document 2 describes that a polyimide obtained by curing a polyimide precursor obtained by using a monomer having a fluorene skeleton and having a siloxane unit has excellent YI, haze, and heat resistance. Patent Documents 3 and 4 describe that a polyimide obtained by curing a polyamic acid obtained by using a monomer having a fluorene skeleton has excellent transparency, thermal properties, and mechanical properties (after moisture absorption), and is suitable for use in flexible displays. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 148441 [Patent Document 2] Korean Patent No. 10-1787941 [Patent Document 3] International Publication No. 2014 / 007112 [Patent Document 4] International Publication No. 2016 / 088641 Summary of the Invention [Problem to be solved by the invention]

[0005] When a transparent polyimide resin is to be applied to a flexible substrate, a resin composition containing a polyimide precursor is applied onto a substrate such as a glass substrate as a support to form a coating film, which is then heated and dried, and the polyimide precursor is further imidized to form a polyimide film, and a device is formed on the film as necessary, and then the film is peeled off from the glass substrate or the like to obtain the desired product.

[0006] In recent years, with the increase in size of displays and other applications for flexible substrates, a slit coater may be used to coat a resin composition containing a polyimide precursor on a substrate such as a glass substrate. In the case of coating with a slit coater, a parameter that affects the film to be coated is the coater gap (i.e., a set value that specifies the distance between the glass substrate and the slit nozzle). As the coater gap becomes smaller, the possibility of the nozzle coming into contact with the substrate and damaging the slit nozzle increases if the flatness of the glass substrate is poor. In particular, with the increase in size of displays and other applications in recent years, it has become necessary to make this coater gap sufficiently large.

[0007] The present inventors carried out a coating evaluation of a slit coater using a polyimide precursor having a molecular weight and skeleton similar to those described in Patent Documents 2 to 4, and found that the coating properties were insufficient.

[0008] Therefore, an object of the present invention is to provide a polyimide precursor and a resin composition thereof which have good coating properties for slit coating, excellent productivity, and excellent optical properties required for flexible substrate applications. [Means for solving the problem]

[0009] As a result of intensive research, the present inventors have found that by specifying the molecular weight of a polyimide precursor having a fluorene skeleton and a siloxane unit and / or specifying the content of a silicon-containing compound in a resin composition, not only is the coating property of the slit coat good and the productivity excellent, but also the optical properties required for flexible substrate applications are excellent, and have completed the present invention. An example of an embodiment of the present invention is as follows. [1] The following formula (1): [ka] {in formula, P 1 represents a divalent organic group, and P 1 When there are multiple, they may be the same or different, and P 2 is expressed by the following formula (2): [ka] (In the formula, Q 1 and Q 2 are each independently at least one selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a halogenated alkyl group, X is each independently at least one selected from the group consisting of -O-, -C(=O)-, -C(=O)O-, and -C(=O)NH-, m and n are each independently an integer of 0 to 2, and l is an integer of 0 or 1. represents a tetravalent group represented by P 2 When there are a plurality of, they may be the same or different, and p is a positive integer. The polyimide precursor is represented by the following formula (3): [ka] {in formula, P 3 and P 4 each independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms; P 3 When there are multiple, they may be the same or different, and P 4 When there are a plurality of , they may be the same or different, and q is a positive integer. and the weight average molecular weight of the polyimide precursor is 90,000 to 250,000. [2] 2. The polyimide precursor according to item 1, wherein the weight average molecular weight of the polyimide precursor is greater than 96,000. [3] The tetravalent group represented by the formula (2) is 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, or 9,9-Bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride 3. The polyimide precursor according to item 1 or 2, which is a residue of [4] 4. The polyimide precursor according to any one of items 1 to 3, wherein the polyimide precursor is a copolymer of a tetracarboxylic dianhydride and a diamine, and the tetracarboxylic dianhydride includes at least one of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride. [5] The diamine is 2,2'-diaminobis(trifluoromethyl)biphenyl, 4,4' and / or 3,3'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, and 1,4-Diaminocyclohexane 5. The polyimide precursor according to any one of items 1 to 4, comprising at least one selected from the group consisting of: [6] 6. The polyimide precursor according to any one of items 1 to 5, wherein the polyimide precursor has a weight average molecular weight of 200,000 or less. [7] 7. The polyimide precursor according to any one of items 1 to 6, wherein the polyimide precursor has a weight average molecular weight of 110,000 to 200,000. [8] 8. The polyimide precursor according to any one of items 1 to 7, wherein the polyimide precursor has a weight average molecular weight of 180,000 or less. [9] 9. The polyimide precursor according to any one of items 1 to 8, wherein the polyimide precursor has a weight average molecular weight of 139,000 or more.

[10] The polyimide precursor according to any one of items 1 to 9; With a solvent; A resin composition comprising:

[11] A resin composition comprising a polyimide precursor and a solvent, The polyimide precursor is represented by the following formula (1): [ka] {in formula, P 1 represents a divalent organic group, and P 1 When there are multiple, they may be the same or different, and P 2 is expressed by the following formula (2): [ka] (In the formula, Q 1 and Q 2 are each independently at least one selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a halogenated alkyl group, X is each independently at least one selected from the group consisting of -O-, -C(=O)-, -C(=O)O-, and -C(=O)NH-, m and n are each independently an integer of 0 to 2, and l is an integer of 0 or 1. represents a tetravalent group represented by P 2When there are a plurality of, they may be the same or different, and p is a positive integer. and the polyimide precursor is represented by the following formula (3): [ka] {in formula, P 3 and P 4 each independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms; P 3 When there are multiple, they may be the same or different, and P 4 When there are a plurality of , they may be the same or different, and q is a positive integer. The structural unit represented by The resin composition is represented by the following general formula (4): [ka] {in formula, P 5 and P 6 are each independently a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms or an aromatic group having 6 to 10 carbon atoms, and r is an integer of 3 or greater.} A resin composition comprising a compound represented by the formula: in an amount of more than 0 ppm and not more than 300 ppm based on the mass of the resin composition, and / or in an amount of more than 0 ppm and not more than 1500 ppm based on the mass of the solid content in the resin composition.

[12] A resin composition comprising a polyimide precursor and a solvent, The polyimide precursor is represented by the following formula (1): [ka] {in formula, P 1 represents a divalent organic group, and P 1 When there are multiple, they may be the same or different, and P 2 is expressed by the following formula (2): [ka] (In the formula, Q 1 and Q 2are each independently at least one selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a halogenated alkyl group, X is each independently at least one selected from the group consisting of -O-, -C(=O)-, -C(=O)O-, and -C(=O)NH-, m and n are each independently an integer of 0 to 2, and l is an integer of 0 or 1. represents a tetravalent group represented by P 2 When there are a plurality of, they may be the same or different, and p is a positive integer. and the polyimide precursor is represented by the following formula (3): [ka] {in formula, P 3 and P 4 each independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms; P 3 When there are multiple, they may be the same or different, and P 4 When there are a plurality of , they may be the same or different, and q is a positive integer. The structural unit represented by The resin composition is represented by the following general formula (4): [ka] {in formula, P 5 and P 6 are each independently a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms or an aromatic group having 6 to 10 carbon atoms, and r is an integer of 3 or greater.} The compound represented by the formula: The polyimide precursor is represented by the following general formula (5): [ka] {where, R 1 are each independently a single bond or a divalent organic group having 1 to 10 carbon atoms; R 2 and R 3 are each independently a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, R 4and R 5 are each independently 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; R 6 and R 7 At least one of L is an organic group having an unsaturated aliphatic hydrocarbon group. 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 hydroxyl group, an epoxy group, or a mercapto group, i is an integer of 1 to 200, and j and k are each independently an integer of 0 to 200.} A copolymer containing a silicon-containing compound represented by the formula (I), a tetracarboxylic dianhydride, and a diamine as monomer units, A resin composition, wherein the content of the compound represented by the general formula (4) in the resin composition is more than 0 ppm and 450 ppm or less, when the total amount of the silicon-containing compounds represented by the general formulas (4) and (5) is 100 parts by mass.

[13] Item 13. The resin composition according to item 11 or 12, wherein the polyimide precursor has a weight average molecular weight of 90,000 to 250,000.

[14] 14. The resin composition according to any one of items 11 to 13, wherein the weight average molecular weight of the polyimide precursor exceeds 96,000.

[15] Item 15. The resin composition according to any one of items 11 to 14, wherein the polyimide precursor has a weight average molecular weight of 139,000 or more and / or 180,000 or less.

[16] In the general formula (4), P 5 and P 6 and each independently represent a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms, and r is 3 to 8.

[17] In the general formula (4), P 5 and P 6and each independently represent an aromatic group having 6 to 10 carbon atoms, and r is 3 to 8.

[18] Item 18. The resin composition according to any one of items 10 to 17, wherein the solid content of the resin composition is 9 to 25 mass%, 9 to 20 mass%, 9 to 15 mass%, or 9 to 13 mass%.

[19] Item 19. The resin composition according to any one of items 10 to 18, wherein a polyimide resin film which is a cured product of the polyimide precursor is used for a flexible substrate.

[20] 20. The resin composition according to any one of items 10 to 19, wherein a polyimide resin film which is a cured product of the polyimide precursor is used for a flexible display. [twenty one] A coating step of coating a surface of a support with the resin composition according to any one of items 10 to 20; a film-forming step of heating the resin composition to form a polyimide resin film; a peeling step of peeling the polyimide resin film from the support; A method for producing a polyimide film comprising the steps of: [twenty two] Item 22. The method for producing a polyimide film according to item 21, further comprising, prior to the peeling step, irradiating the resin composition with a laser from the support side. [twenty three] A coating step of coating a surface of a support with the resin composition according to any one of items 10 to 20; a film-forming step of heating the resin composition to form a polyimide resin film; an element forming step of forming an element on the polyimide resin film; a peeling step of peeling the polyimide resin film on which the elements are formed from the support; A method for manufacturing a display comprising: [twenty four] A coating step of coating a surface of a support with the resin composition according to any one of items 10 to 20; a film-forming step of heating the resin composition to form a polyimide resin film; an element forming step of forming an element on the polyimide resin film; A method for producing a laminate, comprising: [twenty five] Item 25. The method for producing a laminate according to item 24, further comprising the step of peeling off the polyimide resin film on which the element is formed from the support.

[26] Item 26. A method for producing a flexible device, comprising producing a laminate by the laminate production method according to item 24 or 25.

[27] 21. A polyimide film which is a cured product of the resin composition according to any one of items 10 to 20. Effect of the Invention

[0010] According to the present invention, it is possible to provide a polyimide precursor film or polyimide film that has excellent coating properties when slit-coated with a resin composition containing a polyimide precursor, for example, by suppressing leakage from a slit nozzle and dripping of a coating film, and by ensuring an appropriate coater gap, and that is excellent in mass productivity. In addition, the polyimide film according to the present invention has excellent optical properties when used as a flexible substrate. [Brief description of the drawings]

[0011] [Figure 1] 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 the display of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An exemplary embodiment of the present invention (hereinafter, abbreviated as "the present embodiment") will be described in detail below. The present invention is not limited to the present embodiment, and can be practiced with various modifications within the scope of the gist of the present invention. In addition, in the present specification, the upper and lower limits of each numerical range can be arbitrarily combined.

[0013] [Polyimide precursor] The polyimide precursor according to the present embodiment is represented by the following general formula (1): The following formula (1): [ka] {in formula, P 1 represents a divalent organic group, and P 1 When there are multiple, they may be the same or different, and P 2 is expressed by the following formula (2): [ka] (In the formula, Q 1 and Q 2 are each independently at least one selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a halogenated alkyl group, X is each independently at least one selected from the group consisting of -O-, -C(=O)-, -C(=O)O-, and -C(=O)NH-, m and n are each independently an integer of 0 to 2, and l is an integer of 0 or 1. represents a tetravalent group represented by P 2 When there are a plurality of, they may be the same or different, and p is a positive integer. and the following formula (3): [ka] {in formula, P 3 and P 4 each independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms; P 3 When there are multiple, they may be the same or different, and P 4 When there are a plurality of , they may be the same or different, and q is a positive integer. It has a structural unit represented by the following formula:

[0014] Although not wishing to be bound by theory, it is believed that the polyimide precursor has a fluorene skeleton that is more flexible than a skeleton derived from pyromellitic acid or biphenyltetracarboxylic acid, and thus can reduce the retardation (Rth) in the thickness direction of the polyimide film. From the viewpoint of reducing the retardation (Rth), it is preferable that l is 0 in formula (2).

[0015] The weight average molecular weight (Mw) of the polyimide precursor according to the present embodiment is 70,000 or more and 250,000 or less. The Mw of the polyimide precursor is 70,000 or more from the viewpoint of being within the range of molecular weights that can be slit coated and / or having a region of applicable solid content, thereby providing excellent coating evaluation, and from the viewpoint of coating evaluation and the elongation and YI (yellowness index) of a polyimide film obtained by curing a composition containing the polyimide precursor, it is preferably 90,000 or more, more than 96,000 or 110,000 or more, more preferably 120,000 or more, and even more preferably 130,000 or more or 139,000 or more. Moreover, from the viewpoint of synthesis of the polyimide precursor, the Mw of the polyimide precursor is 250,000 or less, and preferably less than 250,000, and from the viewpoint of synthesis and the haze of the polyimide film, it is more preferably 220,000 or less, further preferably 200,000 or less, and may be 180,000 or less.

[0016] In formula (1), p is a positive integer, and is preferably an integer within a range of 140 to 500, and more preferably an integer within a range of 180 to 440, from the viewpoint of the weight-average molecular weight of the polyimide precursor.

[0017] The polyimide precursor represented by formula (1) is a polyimide precursor represented by formula (2) 2 and an acid dianhydride having a P 1 It is preferable that the copolymer is a copolymer with a diamine having a group, and the copolymer has the following general formula (5): [ka] {where, R1 are each independently a single bond or a divalent organic group having 1 to 10 carbon atoms; R 2 and R 3 are each independently a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, R 4 and R 5 are each independently 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; R 6 and R 7 At least one of L is an organic group having an unsaturated aliphatic hydrocarbon group. 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 hydroxyl group, an epoxy group, or a mercapto group, i is an integer of 1 to 200, and j and k are each independently an integer of 0 to 200.} It is more preferable that the copolymer is a copolymer containing a silicon-containing compound represented by the following formula (I) and a tetracarboxylic dianhydride and a diamine as monomer units, and the copolymer may have any terminal group derived from these monomer units.

[0018] acid dianhydride P represented by formula (2) 2The group can be, for example, a tetravalent group derived from a fluorene skeleton (a residue of an acid anhydride having a fluorene skeleton). Examples of acid anhydrides having a fluorene skeleton include 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene acid dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene acid dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-phenylphenyl]fluorene dianhydride, and 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-phenylphenyl]fluorene dianhydride. Fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-phenylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-phenylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-methylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-methylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-methylphenyl]fluorene dianhydride 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-methylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-ethylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-ethylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-ethylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-ethylphenyl]fluorene dianhydride 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-propylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-propylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-propylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-propylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-butylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-butylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-butylphenyl]fluorene dianhydride, 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-butylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-butylphenyl]fluorene dianhydride Examples of the fluorene dianhydride include 9,9-bis[4-(2,3-dicarboxyphenoxy)-3-t-butylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-t-butylphenyl]fluorene dianhydride, and 9,9-bis[4-(2,3-dicarboxyphenoxy)-2-t-butylphenyl]fluorene dianhydride. Among these aromatic bis(ether acid anhydride) compounds, 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-phenylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-phenylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-3-methylphenyl]fluorene dianhydride, 9,9-bis[4-(3,4-dicarboxyphenoxy)-2-methylphenyl]fluorene dianhydride, 4,4'-((9H-fluorenyl)bis(4,1-phenyleneoxycarbonyl))diphthalic dianhydride, and compounds represented by the following general formula: [ka] Examples of the acid anhydride include an acid anhydride having a fluorene skeleton represented by the following formula:

[0019] Among these, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride or 9,9-bis[4-(3,1-, 3,2-, 3,3-, or 3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride is preferred, and from the viewpoint of cost, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) or 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride (BPAF-PA) is more preferred.

[0020] The polyimide precursor represented by formula (1) is preferably a polyimide having a P represented by formula (2) from the viewpoint of reducing the haze of the film and the thread-like foreign matter adhering to the coating film. 2 In addition to the structural unit having the group, it is preferable that the structural unit has a residue of an acid dianhydride other than fluorene dianhydride. Examples of acid dianhydrides other than fluorene dianhydride include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2 dicarboxylic anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'- Benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA), methylene-4,4'-diphthalic 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 acid dianhydride (ODPA), p-phenylene bis(trimellitate anhydride) (TAHQ), 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 1,3-bis(3,4-dicarboxyphenoxy)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-tetramethyldisiloxane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,3,6,7-tetramethyldisilox ...7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride (e.g., 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, etc.), cyclohexanetetracarboxylic dianhydride (e.g., 1,2,4,5-cyclohexanetetracarboxylic dianhydride, etc.), norbornane-2-spiro-α-cyclopentanone-α'-spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic dianhydride (CpODA), and 1,2,7,8-phenanthrenetetracarboxylic dianhydride, etc. Among these, from the viewpoint of reducing haze and thread-like foreign matter, at least one selected from the group consisting of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, cyclohexanetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), norbornane-2-spiro-α-cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic dianhydride (CpODA), p-phenylene bis(trimellitate anhydride) (TAHQ), and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) is preferred, and at least one of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride is more preferred.

[0021] The content of the acid dianhydride derived from a fluorene skeleton in all the acid dianhydrides used as raw materials for the polyimide precursor is preferably 20 mol % or more, more preferably 50 mol % or more, and even more preferably 80 mol % or more, from the viewpoints of a low Rth of the polyimide film and adhesion between the support and the polyimide film.

[0022] Diamine P in Equation (1) 1Examples of diamines containing a group include diaminodiphenyl sulfone (e.g., 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone), p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)benzidine (also known as 4,4'-diamino-2,2'-bis (trifluoromethyl)biphenyl), m-tolidine (synonym: 4,4'-diamino-2,2'-dimethylbiphenyl), 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)furan] 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-amino Examples of suitable amines include 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis(4-aminophenyl)fluorene, cyclohexanediamines (e.g., 1,4-diaminocyclohexane, 1,2-diaminocyclohexane, and their cis isomers, trans isomers, or cis·trans mixtures), 4,4'-diaminodicyclohexylmethane (e.g., New Japan Chemical Co., Ltd., product name "Wondamin"), and 1,4-bis(3-aminopropyldimethylsilyl)benzene.The diamine may be used alone or in combination of two or more. It is preferable to copolymerize diaminodiphenylsulfone with another diamine.

[0023] Among these, from the viewpoint of reducing the transparency, Rth, YI value and haze of the film, at least one selected from the group consisting of 2,2'-diaminobis(trifluoromethyl)biphenyl, 4,4' and / or 3,3'-diaminodiphenylsulfone, 9,9-bis(4-aminophenyl)fluorene and 1,4-diaminocyclohexane is preferred. 1 Preferably, the diamine containing group comprises diaminodiphenylsulfone (DAS), for example 4,4'-diaminodiphenylsulfone, and / or 3,3'-diaminodiphenylsulfone.

[0024] The content of each of the above-mentioned 2,2'-diaminobis(trifluoromethyl)biphenyl, 4,4' and / or 3,3'-diaminodiphenylsulfone, 9,9-bis(4-aminophenyl)fluorene, and 1,4-diaminocyclohexane diamines in the total diamines may be 50 mol% or more, or 70 mol% or more, or 90 mol% or more, or 95 mol% or more. The greater the amount of diaminodiphenylsulfone and / or each of the above diamines, the lower the transparency, Rth, YI value, etc. of the polyimide film, so this is preferred. As the diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone is particularly preferred from the viewpoint of reducing the YI value.

[0025] Structural unit represented by formula (3) The polyimide precursor according to the present embodiment has a structural unit represented by the above formula (3). Based on the mass of the polyimide precursor, the lower limit of the ratio of the structural portion represented by formula (3) is preferably 5 mass% or more, more preferably 6 mass% or more, and even more preferably 7 mass% or more, from the viewpoint of reducing the residual stress of the polyimide film generated between the support and the polyimide precursor. Based on the mass of the polyimide precursor, the upper limit of the ratio of the structural portion represented by formula (2) is preferably 40 mass% or less, more preferably 30 mass% or less, and even more preferably 25 mass% or less, from the viewpoint of the transparency and heat resistance of the polyimide film. In the above general formula (3), q is a positive integer, and is preferably 1 to 200, and more preferably 3 to 200, from the viewpoint of the heat resistance of the resulting polyimide.

[0026] The polyimide precursor may have the structural unit represented by formula (3) at any position in the molecule, but from the viewpoints of the type of siloxane monomer, cost, and the molecular weight of the resulting polyimide precursor, it is preferable that the structural unit represented by formula (3) is derived from a silicon-containing compound, such as a silicon-containing diamine. Examples of silicon-containing diamines include those represented by the following formula (6): [ka] {in formula, P 5 each independently represents a divalent hydrocarbon group and may be the same or different; P 3 and P 4 is the same as defined in formula (2), and l represents an integer of 1 to 200.} Preferred is a diamino(poly)siloxane represented by the following formula:

[0027] P in the above general formula (6) 5 Preferred structures of P include a methylene group, an ethylene group, a propylene group, a butylene group, and a phenylene group. 3 and P 4Preferred structures include a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group, etc. In the above general formula (6), l is an integer of 1 to 200, and is preferably an integer of 3 to 200 from the viewpoint of the heat resistance of a polyimide obtained by using the compound represented by general formula (6).

[0028] The number average molecular weight (=functional group equivalent*2) of the compound represented by formula (6) is preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more, from the viewpoint of reducing residual stress generated between the obtained polyimide film and the support. From the viewpoint of transparency (particularly low haze) of the obtained polyimide film, the number average molecular weight is preferably 12,000 or less, more preferably 10,000 or less, and even more preferably 8,000 or less.

[0029] Specific examples of the compound represented by the general formula (6) include methylphenyl silicone oil modified with amines at both ends (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-1660B-3 (number average molecular weight 4400), X22-9409 (number average molecular weight 1300)), dimethyl silicone modified with amino at both ends (manufactured by Shin-Etsu Chemical Co., Ltd.: X22-161A (number average molecular weight 1600), X22-161B (number average molecular weight 3000), KF-8012 (number average molecular weight 4400), 8008, 8012, Toray Dow Corning Co., Ltd.: BY16-835U (number average molecular weight 900), Chisso Corporation: Silaplane FM3311 (number average molecular weight 1000)), and the like. Among these, methylphenyl silicone oil modified with amines at both ends is preferred from the viewpoint of improving chemical resistance and Tg.

[0030] The copolymerization ratio of the silicon-containing diamine is preferably 0.5 to 30 mass%, more preferably 1.0 to 25 mass%, and even more preferably 1.5 to 20 mass%, based on the total mass of the polyimide precursor. When the silicon-containing diamine is 0.5 mass% or more, the residual stress generated between the support can be effectively reduced. When the silicon-containing diamine is 30 mass% or less, the transparency (especially low haze) of the obtained polyimide film is good, and it is preferable from the viewpoint of realizing a high total light transmittance and a high glass transition temperature.

[0031] Dicarboxylic acids As the acid component for forming the polyimide precursor in this embodiment, a dicarboxylic acid may be used in addition to an acid dianhydride (for example, the tetracarboxylic dianhydride exemplified above) within a range that does not impair its performance, that is, the polyimide precursor according to this embodiment may be a polyamideimide precursor. A film obtained from such a polyimide precursor may have good performance such as mechanical elongation, glass transition temperature Tg, and YI value. Examples of the dicarboxylic acid used include dicarboxylic acids having an aromatic ring and alicyclic dicarboxylic acids. In particular, 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 preferable. The number of carbon atoms referred to here includes the number of carbon atoms contained in the carboxyl group. Among these, dicarboxylic acids having an aromatic ring are preferable.

[0032] Specific examples of dicarboxylic acids having an aromatic ring include isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, 3,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic 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'-oxybiphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3,4 ...oxybisbenzoic acid, 3,3'-oxybiphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3,4'-oxybisbenzoic acid, 3,3'-oxybiphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,5- benzoic 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-carboxyphenyl) phenoxy)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,Examples of the dicarboxylic acids include 1-cyclobutanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, and the like; and 5-aminoisophthalic acid derivatives described in International Publication No. 2005 / 068535. When these dicarboxylic acids are actually copolymerized into a polymer, they may be used in the form of an acid chloride derived from thionyl chloride or an active ester.

[0033] Silicon-containing compound represented by general formula (5) As described above, the polyimide precursor represented by formula (1) is more preferably a copolymer containing the silicon-containing compound represented by general formula (5) above, a tetracarboxylic dianhydride, and a diamine as monomer units.

[0034] L of a silicon-containing compound represented by general formula (5) 1 and L 2 each independently represents an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxyl group, an epoxy group, or a mercapto group. From the viewpoint of the molecular weight of the resulting polyimide precursor, an amino group or an acid anhydride group is preferable, and from the viewpoint of the molecular weight of the polyimide precursor, an amino group is more preferable.

[0035] In general formula (5), R 1are each 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 the divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms include linear or branched alkylene groups such as methylene, ethylene, n-propylene, i-propylene, n-butylene, s-butylene, t-butylene, n-pentylene, neopentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, and n-decylene groups; and cycloalkylene groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, and cyclooctylene groups. The divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of ethylene, n-propylene, and i-propylene.

[0036] In general formula (5), R 2 and R 3are each independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. For example, the monovalent organic group having 1 to 10 carbon atoms may be a linear or branched alkyl group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, or n-decyl group; a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl group; or an aromatic group such as phenyl, tolyl, xylyl, α-naphthyl, or β-naphthyl group. The monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. For example, the monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms may be a linear or branched alkyl group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, or neopentyl group; or a cycloalkyl group such as cyclopropyl, cyclobutyl, or 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, ethyl, and n-propyl.

[0037] In general formula (5), R 4 and R 5are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one of them is a monovalent aromatic group having 6 to 10 carbon atoms. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. For example, the monovalent organic group having 1 to 10 carbon atoms may be a linear or branched alkyl group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, or n-decyl group; a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl group; or an aromatic group such as phenyl, tolyl, xylyl, α-naphthyl, or β-naphthyl group. Examples of the monovalent aromatic group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl groups, and phenyl, tolyl, or xylyl is preferable.

[0038] In general formula (5), R 6 and R 7are 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. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and examples thereof include linear or branched alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; and aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, 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, ethyl, and phenyl. The organic group having an unsaturated aliphatic hydrocarbon group may be an unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, and may be linear, cyclic, or branched. Examples of the unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms include vinyl, allyl, propenyl, 3-butenyl, 2-butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, octenyl, nonenyl, decenyl, ethynyl, propynyl, butynyl, pentynyl, and hexynyl groups. The unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms is preferably at least one selected from the group consisting of vinyl, allyl, and 3-butenyl.

[0039] In general formula (5), R 1 ~R 7 Some or all of the hydrogen atoms in may be substituted with a substituent such as a halogen atom, e.g., F, Cl, or Br, or may be unsubstituted.

[0040] i is an integer from 1 to 200, preferably an integer from 2 to 100, more preferably an integer from 4 to 80, and even more preferably an integer from 8 to 40. j and k are each independently an integer from 0 to 200, preferably an integer from 0 to 50, more preferably an integer from 0 to 20, and even more preferably an integer from 0 to 50.

[0041] In the copolymer, the tetracarboxylic dianhydride and diamine contained as monomer units together with the silicon-containing compound represented by general formula (5) may be the tetracarboxylic dianhydride and diamine listed for formula (1), respectively.

[0042] [Resin composition] The resin composition according to the present embodiment contains the polyimide precursor described above and a solvent. The solvent is not limited to the following solvents, for example: Amide solvents, such as N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), N,N-dimethylacetamide (DMAc), 1,3-dimethylimidazolidinone, tetramethylurea, N,N-dimethylpropionamide, N,N-diethylacetamide, β-alkoxypropionamide, N,N-dimethylformamide, N-methyl-ε-caprolactam, and the following general formula (10): [ka] {where, R 12 is an alkyl group, for example, R 12 = Equamide M100 (trade name: manufactured by Idemitsu Kosan Co., Ltd.), which is represented by a methyl group, and R 12 = Equamide B100 (product name: manufactured by Idemitsu Kosan Co., Ltd.), represented by an n-butyl group. Non-amide solvents, such as tetrahydrofuran (THF), acetonitrile, propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, cyclopentanone, amyl acetate, ethylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, and the like. The solvents described above can be used alone or in combination.

[0043] The solid content of the resin composition containing the polyimide precursor is preferably 9 to 25 mass %, more preferably 9 to 20 mass %, even more preferably 9 to 15 mass %, and still more preferably 9 to 13 mass %, from the viewpoint of the coating properties of slit coating, for example, from the viewpoint of suppressing leakage from the slit nozzle and dripping of the coating film, ensuring an appropriate coater gap, and providing a polyimide precursor film or polyimide film with excellent mass productivity. In this specification, the term "solid content" refers to all components in the resin composition other than the solvent, and liquid monomer components are also included in the mass of the solid content. When the resin composition contains only a solvent and a polyimide precursor, the polyimide precursor corresponds to the solid content, and therefore the mass of the solid content corresponds to the total mass of all monomers contained in the polyimide precursor. The mass of the solid content can also be determined by determining the mass of the solvent by analyzing the resin composition with gas chromatography (hereinafter also referred to as GC), and subtracting the mass of the solvent from the mass of the resin composition.

[0044] <Amount of cyclic siloxane> The resin composition preferably has the following general formula (4): [ka] {in formula, P 5 and P 6 are each independently a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms or an aromatic group having 6 to 10 carbon atoms, and r is an integer of 3 or more, preferably an integer of 3 to 8.} The composition contains a specific amount of a cyclic siloxane compound represented by the formula: In this specification, the amount of cyclic siloxane compounds represented by general formula (4) may specifically be the total amount of compounds in which r=3-8 in general formula (4).

[0045] The amount of the compound represented by formula (4) is preferably more than 0 ppm and not more than 300 ppm, more preferably more than 0 ppm and not more than 70 ppm, and even more preferably more than 0 ppm and not more than 45 ppm, based on the mass of the resin composition. The amount of the compound represented by formula (4) within the above range is preferable from the viewpoint of the YI of the obtained polyimide film and from the viewpoint of reducing the total number of foreign matters adhering to the polyimide resin film in the production process of the polyimide resin film.

[0046] The amount of the compound represented by formula (4) is preferably more than 0 ppm and not more than 1500 ppm, more preferably more than 0 ppm and not more than 500 ppm, and even more preferably more than 0 ppm and not more than 100 ppm, based on the mass of the solid content in the resin composition. When the amount of the compound represented by formula (4) is within the above range, it is preferable from the viewpoint of the YI of the obtained polyimide film and from the viewpoint of reducing the total number of foreign matters adhering to the polyimide resin film in the production process of the polyimide resin film.

[0047] The amount of the compound represented by the general formula (4) is preferably more than 0 ppm and not more than 450 ppm, more preferably more than 0 ppm and not more than 150 ppm, and even more preferably more than 0 ppm and not more than 10 ppm, when the total amount of the silicon-containing compounds represented by the general formulas (4) and (5) described above is taken as 100 parts by mass. When the amount of the compound represented by the general formula (4) is within the above range, it is preferable from the viewpoint of the YI of the obtained polyimide film and the viewpoint of reducing the total number of foreign matters attached to the polyimide resin film in the production process of the polyimide resin film.

[0048] <Additional ingredients> The resin composition according to this embodiment may further contain additional components such as a surfactant and an alkoxysilane compound in addition to the components described above.

[0049] [Method of producing resin composition] The method for producing the resin composition in this embodiment is not particularly limited, and can be, for example, the following method.

[0050] <Adjustment of silicon-containing compound content> The resin composition of this embodiment can be produced by polycondensation reaction of polycondensation components including an acid dianhydride, a diamine, and a silicon-containing compound. As a method for adjusting the total amount of the compound represented by general formula (4) contained in the resin composition of this embodiment, for example, the silicon-containing compound is purified before the polycondensation reaction to control the total amount of the compound represented by general formula (4). Alternatively, the resin composition may be purified after the polycondensation reaction to control the total amount of the compound represented by general formula (4). In any case, the total amount of the compound represented by general formula (4) in the polyimide precursor composition is adjusted to be more than 0 ppm.

[0051] As a method for purifying a silicon-containing compound, for example, stripping can be performed while blowing an inert gas, such as nitrogen gas, into a silicon-containing compound in an arbitrary container. The stripping temperature is preferably 150°C or more and 300°C or less, more preferably 1600°C or more and 300°C or less, and even more preferably 200°C or more and 300°C or less. The lower the stripping vapor pressure, the more preferable it is, and it is 1000 Pa or less, more preferably 300 Pa or less, even more preferably 200 Pa or less, and even more preferably 133.32 Pa (1 mmHg) or less. The stripping time is preferably 2 hours or more and 12 hours or less, more preferably 4 hours or more and 12 hours or less, and even more preferably 6 hours or more and 10 hours or less. By adjusting the above conditions, the total amount of the compound represented by general formula (4) can be controlled within a preferred range. Also, in the step of reducing the amount of the compound represented by general formula (4) contained in the silicon-containing compound represented by general formula (5), it is preferable to subject the resin composition to a stripping treatment under conditions of 150°C to 300°C and 1000 Pa or less for 2 to 12 hours.

[0052] Synthesis of polyimide precursor The polyimide precursor of the present embodiment can be synthesized by polycondensation reaction of polycondensation components including acid dianhydride, diamine, and silicon-containing compound. The silicon-containing compound is preferably purified as described above. In a preferred embodiment, the polycondensation components are composed of acid dianhydride, diamine, and silicon-containing compound. The polycondensation reaction is preferably carried out in a suitable solvent. Specifically, for example, a method can be mentioned in which a predetermined amount of diamine component and silicon-containing compound are dissolved in a solvent, and then a predetermined amount of acid dianhydride is added to the obtained diamine solution and stirred.

[0053] From the viewpoints of increasing the molecular weight of the polyimide precursor resin and the slit coating properties of the resin composition, the molar ratio of the acid dianhydride to the diamine when synthesizing the polyimide precursor is preferably in the range of 100:90 to 100:110 (0.90 to 1.10 molar parts of diamine per 1 molar part of acid dianhydride), and more preferably in the range of 100:95 to 100:105 (0.95 to 1.05 molar parts of diamine per 1 molar part of acid dianhydride).

[0054] The molecular weight of the polyimide precursor can be controlled by adjusting the types of acid dianhydride, diamine and silicon-containing compound, the molar ratio of the acid dianhydride to the diamine, the addition of an end-capping agent, adjustment of reaction conditions, etc. The closer the molar ratio of the acid dianhydride component to the diamine component is to 1:1, and the smaller the amount of end-capping agent used, the higher the molecular weight of the polyimide precursor can be.

[0055] It is recommended to use high purity products as the acid dianhydride component and the diamine component. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more. The purity can also be increased by reducing the water content in the acid 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-mentioned purity, and it is more preferable that all types of acid dianhydride components and diamine components used have the above-mentioned purity.

[0056] In this embodiment, the reaction solvent used in the synthesis of the polyimide precursor can be used as it is as the solvent contained in the resin composition.

[0057] In another embodiment, a solvent can be used that can dissolve the acid dianhydride component, the diamine component, and the resulting polyimide precursor, and that can provide a high molecular weight polymer. Examples of such a solvent include aprotic solvents, phenolic solvents, ethers, and glycol solvents. Aprotic solvents include, for example, the following: Amide solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, and the amide compounds represented by the above general formula (5); Lactone solvents such as γ-butyrolactone and γ-valerolactone; Phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide; Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; Ketone solvents such as cyclohexanone and methylcyclohexanone; Tertiary amine solvents such as picoline and pyridine; Ester solvents such as 2-methoxy-1-methylethyl acetate; etc. Examples of the phenol-based solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol. Examples of ether and glycol solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, and 1,4-dioxane.

[0058] The resin composition of the present embodiment may contain other additional polyimide precursors in addition to the polyimide precursor of the present embodiment. However, the mass ratio of the additional polyimide precursor is preferably 30 mass% or less, more preferably 10 mass% or less, based on the total amount of the polyimide precursors in the resin composition, from the viewpoint of reducing the oxygen dependency of the YI value and the total light transmittance of the polyimide film.

[0059] The polyimide precursor in this embodiment may be partially imidized (partial imidization). By partially imidizing the polyimide precursor, the 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, and preferably 80% or less, more preferably 70% or less, and further preferably 50% or less, from the viewpoint of balancing the solubility of the polyimide precursor in the resin composition and the storage stability of the solution. This partial imidization is obtained by heating the polyimide precursor to dehydrate and ring-close it. This heating can be performed at a temperature of preferably 120 to 200°C, more preferably 150 to 180°C, for preferably 15 minutes to 20 hours, more preferably 30 minutes to 10 hours.

[0060] The polyamic acid obtained by the above reaction may be added with N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal and heated to esterify a part or all of the carboxylic acid, which may be used as the polyimide precursor of this embodiment. The viscosity stability during storage can be improved by the esterification. These ester-modified polyamic acids can also be obtained by reacting the above-mentioned acid dianhydride component with one equivalent of a monohydric alcohol relative to the acid anhydride group, and a dehydration condensing agent such as thionyl chloride or dicyclohexylcarbodiimide, in that order, and then condensing the resulting mixture with a diamine component.

[0061] <Preparation of Resin Composition> When the solvent used in synthesizing the polyimide precursor is different from the solvent contained in the resin composition, the polyimide precursor may be isolated by removing the solvent in the synthesized polyimide precursor solution by an appropriate method such as reprecipitation, solvent distillation, etc. Next, an amide solvent, a non-amide solvent having a boiling point of 160°C or higher or a silicon aggregation inhibitor, and an additional component as desired may be added to the isolated polyimide precursor at a temperature range of room temperature (25°C) to 80°C, and stirred and mixed to prepare the resin composition according to this embodiment.

[0062] After preparing the resin composition as described above, the resin composition may be heated, for example, at 130 to 200°C for 5 minutes to 2 hours to dehydrate and imidize a part of the polyimide precursor to an extent that does not cause precipitation of the polymer (partial imidization). The imidization rate can be controlled by controlling the heating temperature and heating time. By partially imidizing the polyimide precursor, the viscosity stability during storage of the resin composition can be improved.

[0063] The solution viscosity of the resin composition is preferably 500 to 100,000 mPa·s, more preferably 1,000 to 50,000 mPa·s, and even more preferably 3,000 to 20,000 mPa·s, from the viewpoint of slit coating performance. Specifically, in order to prevent leakage from the slit nozzle, the solution viscosity is preferably 500 mPa·s or more, more preferably 1,000 mPa·s or more, and even more preferably 3,000 mPa·s or more. In addition, in order to prevent clogging of the slit nozzle, the solution viscosity is preferably 100,000 mPa·s or less, more preferably 50,000 mPa·s or less, and even more preferably 20,000 mPa·s or less.

[0064] Furthermore, if the solution viscosity of the resin composition during synthesis of the polyimide precursor is higher than 200,000 mPa·s, a problem may occur in that stirring during synthesis becomes difficult. However, even if the solution becomes highly viscous during synthesis, it is possible to obtain a resin composition with a viscosity that is easy to handle by adding a solvent after the reaction is completed and stirring. The solution viscosity of the resin composition in this embodiment is a value measured at 23°C using an E-type viscometer (for example, VISCONICEHD, manufactured by Toki Sangyo).

[0065] From the viewpoint of viscosity stability during storage of the resin composition, the water content of the resin composition of this embodiment is preferably 3,000 ppm by mass or less, more preferably 2,500 ppm by mass or less, even more preferably 2,000 ppm by mass or less, still more preferably 1,500 ppm by mass or less, particularly preferably 1,000 ppm by mass or less, particularly preferably 500 ppm by mass or less, particularly preferably 300 ppm by mass or less, and particularly preferably 100 ppm by mass or less.

[0066] [Polyimide film and its manufacturing method] The resin composition of the present embodiment can be used to provide a polyimide film (hereinafter, also referred to as a polyimide resin film). The polyimide resin film can be a cured product of the polyimide precursor described above, and is preferably used for a flexible substrate, and more preferably used for a flexible display.

[0067] The method for producing a polyimide film according to the present embodiment includes the following steps: a coating step of coating the resin composition of the present embodiment on a surface of a support; a film-forming step of heating the resin composition to form a polyimide resin film; an irradiation step of irradiating the resin composition with a laser from the support side, if desired; A peeling step of peeling the polyimide resin film from the support; Includes.

[0068] <Coating process> In the coating step, the resin composition of the present embodiment 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 formation step (heating step) and has good releasability in the peeling step. Examples of the support include glass substrates, such as alkali-free glass substrates; silicon wafers; resin substrates such as PET (polyethylene terephthalate), OPP (oriented polypropylene), polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyethersulfone, polyphenylenesulfone, and polyphenylenesulfide; and metal substrates such as stainless steel, alumina, copper, and nickel.

[0069] When a thin-film polyimide molded product is to be formed, for example, a glass substrate or a silicon wafer is preferred, and when a thick-film or sheet-like polyimide molded product is to be formed, a support made of, for example, PET (polyethylene terephthalate), OPP (oriented polypropylene), etc. is preferred.

[0070] Examples of the coating method include generally coating methods using a doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, bar coater, spin coating, spray coating, dip coating, and printing techniques such as screen printing and gravure printing. For the resin composition of the present embodiment, coating by slit coating is preferred. The coating thickness should be appropriately adjusted depending on the desired resin film thickness and the content of the polyimide precursor in the resin composition, but 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 to 80° C. in order to reduce the viscosity and improve workability.

[0071] Optional drying process A drying step may be performed following the coating step, or the drying step may be omitted and the process may proceed directly to the next film formation step (heating step). The drying step can be performed by placing the resin composition under a vacuum condition of 100 Pa or less for the purpose of removing the organic solvent in the resin composition. When performing the drying step, for example, a suitable device such as a hot plate, a box-type dryer, or a conveyor-type dryer can be used. The temperature of the drying step is preferably 80 to 200°C, more preferably 100 to 150°C. The time for which the drying step is performed is preferably 1 minute to 10 hours, more preferably 3 minutes to 5 hours. As described above, a coating film containing a polyimide precursor is formed on a support.

[0072] <Film formation process> Subsequently, a film forming step (heating step) is performed. The heating step is a step for removing the organic solvent contained in the coating film and for advancing the imidization reaction of the polyimide precursor in the coating film to obtain a polyimide resin film. This heating step can be performed by placing the resin composition under a vacuum condition of 100 Pa or less using an apparatus such as an inert gas oven, a hot plate, a box-type dryer, or a conveyor-type dryer. This step can be performed simultaneously with the drying step, or both steps can be performed sequentially.

[0073] The heating step may be performed in an air atmosphere, but is preferably performed in an inert gas atmosphere from the viewpoints of safety, good transparency, low retardation in the thickness direction (Rth) and low YI value of the resulting polyimide film. Examples of inert gases include nitrogen and argon. The heating temperature may be appropriately set depending on 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 it is 250°C or higher, imidization proceeds well, and if it is 550°C or lower, inconveniences such as a decrease in transparency and deterioration of heat resistance of the resulting polyimide film can be avoided. The heating time is preferably about 0.1 to 10 hours.

[0074] In the present embodiment, the oxygen concentration of the surrounding atmosphere in the heating step is preferably 2,000 ppm by mass or less, more preferably 100 ppm by mass or less, and even more preferably 10 ppm by mass or less, from the viewpoints of the transparency and YI value of the resulting polyimide film. By performing 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 set to 30 or less.

[0075] <Peeling process> In the peeling step, the polyimide resin film on the support is peeled off after being cooled, for example, to room temperature (25° C.) to about 50° C. Specifically, the peeling step can be carried out by any one of the following methods (a) to (c). (A) A method in which a release layer is formed on a support before applying a resin composition to the support, and then a structure including a polyimide resin film / release layer / support is obtained, and the polyimide resin film is peeled off. Examples of the release layer include Parylene (registered trademark, manufactured by Japan Parylene LLC) and tungsten oxide; vegetable oil-based, silicone-based, fluorine-based, alkyd-based and other release agents may also be used (see JP 2010-067957 A, JP 2013-179306 A, etc.).

[0076] (a) A method in which an etchable metal substrate is used as a support, a structure including a polyimide resin film / support is obtained, and then the metal is etched with an etchant to obtain a polyimide resin film. Examples of metals that can be used include copper (specifically, electrolytic copper foil "DFF" manufactured by Mitsui Mining & Smelting Co., Ltd.), aluminum, etc. Examples of etchants that can be used include ferric chloride for copper, and dilute hydrochloric acid for aluminum. In the method (a), when copper is used as the support, the YI value of the obtained polyimide resin film tends to be large and the elongation tends to be small. This is considered to be due to the effect of copper ions.

[0077] (c) A method in which after obtaining a construct containing a polyimide resin film / support, an adhesive film is attached to the surface of the polyimide resin film, the adhesive film / polyimide resin film is separated from the support, and then the polyimide resin film is separated from the adhesive film.

[0078] <Irradiation process> In addition, from the viewpoint of the refractive index difference between the front and back of the obtained polyimide resin film, the YI value, and the elongation, it is preferable to carry out an irradiation step of irradiating the resin composition with a laser from the support side prior to this peeling step. Specifically, the irradiation step can be carried out as follows. A method of producing a structure including a polyimide resin film / support by the above method, and then irradiating a laser from the support side of the structure to ablate the interface between the support and the polyimide resin film, thereby peeling off the polyimide resin. Examples of the type of laser include solid (YAG) laser and gas (UV excimer) laser. It is preferable to use a spectrum with a wavelength of 308 nm or the like (see JP-T-2007-512568, JP-T-2012-511173, etc.). This irradiation step can be used in combination with the above-mentioned peeling step (A).

[0079] [Effect of cyclic siloxane purification on polyimide films] From the viewpoint of obtaining good optical properties, the YI value at a film thickness of 10 μm of the polyimide film obtained from the resin composition of this embodiment is preferably 20 or less, more preferably 18 or less, even more preferably 16 or less, particularly preferably 14 or less, particularly preferably 13 or less, particularly preferably 10 or less, and particularly preferably 7 or less. The YI value differs depending on the monomer skeleton of the polyimide precursor, but when the monomer skeleton is the same, the larger the weight average molecular weight of the polyimide precursor, the smaller the YI value tends to be. In addition, the YI value is influenced by, for example, the amine value of the silicon-containing compound used, and the higher the amine value, the higher the YI value, and the lower the amine value, the lower the YI value. However, a polyimide precursor using a purified silicon-containing compound, i.e., a polyimide precursor in which the total amount of the compound represented by general formula (4) is within the above range, tends to have a lower YI value of the resulting polyimide resin film than a polyimide precursor using an unpurified silicon-containing compound having the same amine value. Although not bound by the mechanism of action, the present inventors have presumed as follows. That is, in the conventional purification method, the non-cyclic low-molecular-weight diamine used in the production of the polyimide precursor remains, and decomposes during polyimide curing to generate radicals, which can cause the YI value to increase (worsen). By reducing the amount of the cyclic siloxane represented by general formula (4), not only the cyclic siloxane represented by general formula (4) is removed during purification, but it is also believed that the low-molecular-weight diamine, which is relatively easy to volatilize, is also removed among the diamine components that increase the amine value. Therefore, it is presumed that the polyimide precursor in which the total amount of the compound represented by the general formula (4) is reduced according to this embodiment will have a more improved YI value of the polyimide resin film. Since it is difficult to reduce the amount of non-cyclic low-molecular-weight diamines by the conventional purification method, even if purification is performed, the degree of improvement in the YI value of the polyimide resin film is thought to be smaller than that of this embodiment.

[0080] [Rth: Retardation] The Rth of a polyimide film is correlated with the monomer skeleton of the polyimide precursor, and the Rth tends to decrease when a monomer having a fluorene skeleton is used. Although not bound by the mechanism of action, this tendency is thought to be correlated with the molecular orientation and / or crystallinity of the polyimide film. When the polyimide film is used as a display material, Rth is preferably 200 nm or less, more preferably 100 nm or less, because if Rth is 200 or more, the color reproducibility of the image is poor, and in particular, it is difficult to capture the image correctly.

[0081] [Coating evaluation: slit nozzle evaluation] The slit nozzle evaluation of a resin composition containing a polyimide precursor correlates with the weight average molecular weight of the polyimide precursor and the solid content of the resin composition. In the case of a low molecular weight, when a varnish is produced with a low solid content, liquid leakage occurs, which is inappropriate, and in the case of a high molecular weight, when a varnish is produced with a high solid content, clogging occurs at the tip of the slit nozzle, which is inappropriate. It is necessary to apply an appropriate range of weight average molecular weight and solid content.

[0082] [Coating evaluation: Coat gap] The coat gap in slit coating is correlated with the solid content of the resin composition containing the polyimide precursor, and the smaller the solid content, the better. The larger the coat gap, the better, and if it is less than 50 μm, the slit nozzle and the glass substrate may collide when the flatness of the glass is poor, and especially when the substrate size is large, the possibility of collision increases, which is inappropriate from the viewpoint of damage to the slit nozzle.

[0083] [Coating evaluation: Edge evaluation] If the weight-average molecular weight of the polyimide precursor is relatively low, when a varnish is made with a low solid content, edge droop (the phenomenon in which the varnish drips from the coated area after coating and spreads to uncoated areas) occurs, which is inappropriate. If the weight-average molecular weight of the polyimide precursor is relatively high, when a varnish is made with a low solid content, edge bead (the phenomenon in which the thickness of the edge of the coated area increases) occurs, which is inappropriate. It is necessary to apply an appropriate range of weight-average molecular weight and solid content.

[0084] [Factors contributing to the increase in molecular weight of polyimide precursors] As described above, from the viewpoint of coating evaluation, it is preferable that the weight average molecular weight of the polyimide precursor is 70,000 or more. The following factors are considered to be correlated with increasing the Mv of the polyimide precursor to 70,000 or more (hereinafter, also referred to as increasing the molecular weight). (1) The water content of the monomer and the solvent is low. If the water content is high, the acid dianhydride decomposes into tetracarboxylic acid, and the reactivity with the diamine decreases. In the comparative example described below, the synthesis solvent was used after one day of opening, and the monomer was used without drying treatment. On the other hand, in the examples, the synthesis solvent was used immediately after opening, and the monomer was used after drying treatment. As a result, the examples obtained polyimide precursors with a higher weight average molecular weight. (2) The molar ratio of the diamine and the acid dianhydride used in the synthesis is as close to equimolar as possible (1:1). At this time, it is estimated that a part of the acid dianhydride is decomposed by moisture in the air, and therefore the number of moles of the acid dianhydride should also take into consideration the decomposition product. In the examples described later, a polyimide precursor with a large weight average molecular weight could be obtained when the molar ratio of the diamine and the acid dianhydride was closer to equimolar. (3) The reaction temperature is adjusted to the lowest possible temperature, preferably the lowest temperature while the monomer dissolves in the solvent, for example, to room temperature as the minimum set temperature and less than about 80°C as the maximum temperature. This is thought to be because, when the reaction system is at a high temperature, depolymerization is more likely to occur in the polymerization of the polyimide precursor, resulting in a decrease in the degree of polymerization. In the examples described later, the lower the synthesis temperature of the polyimide precursor, the higher the weight average molecular weight of the polyimide precursor that can be obtained.

[0085] [Polyimide film applications] The polyimide film obtained from the resin composition of this embodiment 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, and as a transparent substrate for display devices such as liquid crystal displays, organic electroluminescence displays, field emission displays, and electronic paper. In particular, the polyimide film obtained from the resin composition of this embodiment can be suitably used as a thin film transistor (TFT) substrate, a color filter substrate, a touch panel substrate, and a substrate for a transparent conductive film (ITO, Indium Thin Oxide) in the manufacture of flexible devices. Examples of flexible devices to which the polyimide film of this embodiment 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.

[0086] The process of forming a TFT on a flexible substrate using a polyimide film is typically carried out at a wide temperature range of 150 to 650° C. Specifically, when manufacturing a TFT device using amorphous silicon, a process temperature of 250 to 350° C. is generally required, and the polyimide film of this embodiment must be able to withstand that temperature, so specifically, it is necessary to appropriately select a polymer structure having a glass transition temperature and a thermal decomposition onset temperature equal to or higher than the process temperature.

[0087] When fabricating a TFT device using a metal oxide semiconductor (such as IGZO), a process temperature of 320°C to 400°C is generally required. The polyimide film of this embodiment must be able to withstand this temperature, and therefore it is necessary to appropriately select a polymer structure having a glass transition temperature and a thermal decomposition onset temperature that are equal to or higher than the maximum temperature of the TFT fabrication process.

[0088] When manufacturing a TFT device using low-temperature polysilicon (LTPS), a process temperature of 380°C to 520°C is generally required. The polyimide film of this embodiment must be able to withstand these temperatures, and therefore must have an appropriately selected glass transition temperature and thermal decomposition onset temperature that are equal to or higher than the maximum temperature of the TFT manufacturing process. On the other hand, due to the thermal history, the optical properties (particularly the light transmittance, retardation property and YI value) of the polyimide film tend to decrease as it is exposed to a high-temperature process. However, the polyimide obtained from the polyimide precursor of the present embodiment has good optical properties even after the thermal history.

[0089] As examples of applications of the polyimide film of this embodiment, a display and a method for producing a laminate will be described below.

[0090] [Display manufacturing method] The manufacturing method for the display of the present embodiment includes a coating step of coating the resin composition of the present embodiment onto a surface of a support; a film formation step of heating the resin composition to form a polyimide resin film; an element formation step of forming elements on the polyimide resin film; and a peeling step of peeling the polyimide resin film with the elements formed thereon from the support.

[0091] <Manufacturing example of flexible organic EL display> 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 the display of this embodiment. The organic EL structure 25 in FIG. 1 will be described. For example, an organic EL element 250a emitting red light, an organic EL element 250b emitting green light, and an organic EL element 250c emitting blue light are arranged in a matrix as one unit, and a partition (bank) 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. In addition, a TFT 256 (selected from low-temperature polysilicon (LTPS) and metal oxide semiconductor (IGZO, etc.)) for driving the organic EL element, an interlayer insulating film 258 having a contact hole 257, and a lower electrode 259 are provided on the lower layer 2a showing a CVD multi-layer film (multi-barrier layer) made of silicon nitride (SiN) or silicon oxide (SiO). The organic EL elements are sealed with a sealing substrate 2b, and a hollow portion 261 is formed between each organic EL element and the sealing substrate 2b.

[0092] The manufacturing process of a flexible organic EL display includes a step of preparing a polyimide film on a glass substrate support, and preparing the organic EL substrate shown in FIG. 1 on the top of the polyimide film, a step of preparing a sealing substrate, an assembly step of bonding the two substrates together, and a peeling step of peeling the organic EL display prepared on the polyimide film from the glass substrate support. The organic EL substrate manufacturing process, the sealing substrate manufacturing process, and the assembly process can be performed using known manufacturing processes. Examples are given below, but the present invention is not limited to these. The peeling process is the same as the peeling process of the polyimide film described above.

[0093] For example, referring to FIG. 1, first, a polyimide film is prepared on a glass substrate support by the above-mentioned method, and a multi-barrier layer (lower substrate 2a in FIG. 1) consisting of a multi-layer structure of silicon nitride (SiN) and silicon oxide (SiO) is prepared on the upper part by a CVD method or a sputtering method, and a metal wiring layer for driving a TFT is prepared on the upper part by using a photoresist or the like. An active buffer layer such as SiO is prepared on the upper part by a CVD method, and a TFT device (TFT 256 in FIG. 1) such as a metal oxide semiconductor (IGZO) or low temperature polysilicon (LTPS) is prepared on the upper part. After preparing a TFT substrate for a flexible display, an interlayer insulating film 258 having a contact hole 257 is formed by 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 be paired with the TFT.

[0094] Next, after forming a partition (bank) 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. In addition, an upper electrode (cathode) 255 is formed so as to cover the light-emitting layer 254 and the partition (bank) 251. Thereafter, using a fine metal mask or the like as a mask, an organic EL material emitting red light (corresponding to the organic EL element 250a emitting red light in FIG. 1), an organic EL material emitting green light (corresponding to the organic EL element 250b emitting green light in FIG. 1), and an organic EL material emitting blue light (corresponding to the organic EL element 250c emitting blue light in FIG. 1) are deposited by a known method to prepare an organic EL substrate. The organic EL substrate is sealed with a sealing film or the like (sealing substrate 2b in FIG. 1), and the device above the polyimide substrate is peeled off from the glass substrate support by a known peeling method such as laser peeling, thereby preparing a top-emission type flexible organic EL display. When the polyimide of this embodiment is used, a see-through type flexible organic EL display can be produced. Also, a bottom emission type flexible organic EL display may be produced by a known method.

[0095] <Example of manufacturing flexible liquid crystal displays> A flexible liquid crystal display can be produced using the polyimide film of this embodiment. As a specific production method, a polyimide film is produced on a glass substrate support by the above-mentioned method, and a TFT substrate made of, for example, amorphous silicon, metal oxide semiconductor (IGZO, etc.), and low-temperature polysilicon is produced by using the above-mentioned method. Separately, a polyimide film is produced on a glass substrate support according to the coating process and film formation process of this embodiment, and a color filter glass substrate (CF substrate) equipped with a polyimide film is produced using a color resist or the like according to a known method. A seal material made of a thermosetting epoxy resin or the like is applied by screen printing to one of the TFT substrate and the CF substrate in a frame-shaped pattern lacking a liquid crystal injection port, and spherical spacers made of plastic or silica having a diameter equivalent to the thickness of the liquid crystal layer are scattered on the other substrate.

[0096] Next, the TFT substrate and the CF substrate are bonded together, and the sealing material is cured. Then, liquid crystal material is injected into the space surrounded by the TFT substrate, the CF substrate, and the sealing material by decompression, a thermosetting resin is applied to the liquid crystal injection port, and the liquid crystal material is sealed by heating to form a liquid crystal layer. Finally, the glass substrate on the CF side and the glass substrate on the TFT side are peeled off at the interface between the polyimide film and the glass substrate by a laser peeling method or the like, thereby producing a flexible liquid crystal display.

[0097] <Method of manufacturing laminate> The method for producing the laminate of the present embodiment includes a coating step of coating the resin composition of the present embodiment onto a surface of a support; a film formation step of heating the resin composition to form a polyimide resin film; and an element formation step of forming an element on the polyimide resin film.

[0098] The elements in the laminate include those exemplified in the manufacturing of the flexible device described above. For example, a glass substrate can be used as the support. The preferred specific procedures of the coating step and the film forming step are the same as those described in relation to the manufacturing method of the polyimide film described above. In the element forming step, the above element is formed on the polyimide resin film as a flexible substrate formed on the support. Thereafter, the polyimide resin film and the element may be peeled off from the support in a peeling step, if desired. EXAMPLES

[0099] The present invention will be described in more detail below with reference to examples, but these are described for the purpose of illustration only and the scope of the present invention is not limited to the following examples. Measurements, purification and evaluations in the examples and comparative examples were carried out as follows.

[0100] Measurement and evaluation methods <Weight average molecular weight> The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions. The solvent used was NMP (Wako Pure Chemical Industries, Ltd., for high performance liquid chromatography, dissolved by adding 24.8 mmol / L lithium bromide monohydrate (Wako Pure Chemical Industries, Ltd., purity 99.5%) and 63.2 mmol / L phosphoric acid (Wako Pure Chemical Industries, Ltd., for high performance liquid chromatography) just before measurement). A calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (Tosoh Corporation). Column: Shodex KD-806M (Showa Denko) Flow rate: 1.0mL / min Column temperature: 40℃ Pump: PU-2080Plus (JASCO) Detector: RI-2031Plus (RI: differential refractometer, manufactured by JASCO) and UV-2075Plus (UV-VIS: ultraviolet-visible spectrometer, manufactured by JASCO)

[0101] <Solid content> The total mass of the monomers used in the polyimide precursor can be used as the mass of the solid content contained in the resin composition. Alternatively, the mass of the solid content can be determined by subjecting the resin composition to gas chromatography (hereinafter also referred to as GC) analysis to determine the mass of the solvent, and subtracting the mass of the solvent from the mass of the resin composition. The conditions for GC include the following: Equipment: Gas chromatograph (Agilent, Gas Chromatograph 6890N) Inlet temperature: 280℃ Injection volume: 1μL Oven temperature: After holding at 50°C for 1 minute, increase the temperature to 350°C at a rate of 20°C / min and hold at 350°C for 5 minutes. Carrier gas: He, 1.0 ml / min Column: SGE, BPX5 (0.25 mm diameter x 30 m, film thickness 0.25 μm) Split ratio: 50:1 Detector: Hydrogen flame ionization detector Detector temperature: 355℃

[0102] <Coating evaluation> The polyimide precursor compositions synthesized in the Examples, Comparative Examples, and Reference Examples were subjected to coating evaluation using a slit coater (manufactured by Screen Finetech Solutions Co., Ltd.). The coating evaluation results are shown in Tables 2 to 12.

[0103] (Slit nozzle evaluation) The polyimide precursor compositions (varnishes) synthesized in the Examples, Comparative Examples, and Reference Examples were filled into a slit coater and evaluated according to the following criteria, and the results are shown in the table. After starting to dispense varnish from the nozzle and stopping the dispense, varnish drips from the slit nozzle: Liquid leakage Varnish is not discharged from the nozzle: Clogging No discharge → Changed the surface Can be coated without dripping or clogging: No problem

[0104] (Court Gap) The polyimide precursor compositions (varnishes) synthesized in the Examples, Reference Examples, and Comparative Examples were coated (coating speed 100 mm / sec) on a glass substrate so that the film thickness after imidization (heating at 100°C for 1 hour and then at 400°C for 30 minutes at an oxygen concentration of 10 mass ppm or less) was 10 μm. The coat gap setting values ​​of the slit coater at that time are shown in Tables 2 to 10.

[0105] (Edge Evaluation) Each of the polyimide precursor compositions synthesized in the Examples, Comparative Examples, and Reference Examples was coated onto a glass substrate, transferred to a drying furnace, and heated at 100°C for 1 hour. The edge of the coating was then observed at 10x magnification using a microscope and evaluated according to the following criteria. In addition, the edge bead (protrusion at the edge) of the coating film was measured using a stylus step gauge (P-15: manufactured by KLA Tencor) and evaluated according to the following criteria. If dripping of 0.5 mm or more is observed under microscope at the edge: Dripping When the thickness of the bead is 50% or more of the coating thickness at the edge part: Bead If there is no sagging or edge abnormality: No problem

[0106] (Slit coating possible) The (slit nozzle evaluation), (coat gap) and (edge ​​evaluation) were evaluated according to the following criteria and the results are shown in the table. In a composition using a polyimide precursor having a certain weight average molecular weight, if any solid content is used, and all of the following evaluation results are satisfied, the composition is considered acceptable. In a composition using a polyimide precursor with a certain weight average molecular weight, if none of the following evaluation results are met, even if the solid content is any of the following: Not acceptable Slit nozzle evaluation: No problem Coat gap: 50um or more Edge rating: No problem

[0107] Analysis of low molecular weight cyclic siloxane concentration The raw material silicon-containing compound (hereinafter also referred to as SiDA) and the concentration of the low molecular weight cyclic siloxane of general formula (4) contained in the resin composition of this embodiment were quantitatively analyzed by GC / MS measurement as shown below.

[0108] (1) Overview First, a calibration curve was prepared to quantify the amount of cyclic siloxane. The calibration curve was prepared using a standard sample (manufactured by Tokyo Chemical Industry Co., Ltd.) of cyclic siloxane with n=4 in general formula (4) (hereinafter also referred to as D4 form) according to the method described below. The amount of low molecular weight cyclic siloxanes contained in SiDA was measured by heating SiDA in a pyrolyzer at 100°C for 10 minutes and analyzing the resulting volatile components by GC / MS. The peak area of ​​each compound obtained was converted to the D4 concentration using a calibration curve prepared in advance. The amount of low molecular weight cyclic siloxane contained in the resin composition was measured by heating SiDA in a pyrolyzer at 100°C for 30 minutes and analyzing the resulting volatile components by GC / MS. Using a calibration curve prepared in advance, the peak area of ​​each compound obtained was converted into the D4 isomer concentration. GC / MS measurements were performed using the following equipment. Pyrolyzer: Py-3030iD (Frontier Labs) GC system: 7890B (Agilent Technologies) MSD:5977A (Agilent Technologies) Column: UA-1 (inner diameter 0.25 mm, length 15 m, liquid phase thickness 0.25 μm) (Frontier Lab) All GC / MS measurements were carried out under the following measurement conditions. Column temperature: 40°C for 5 minutes, heated at 20°C / min, held at 320°C for 11 minutes, total 30 minutes Inlet temperature: 320℃ Injection method: Split method (split ratio 1 / 20) Interface temperature: 320℃ Ion source temperature: 230℃ Ionization method: Electron Ionization (EI) Measurement method: SCAN method (m / z 10-800)

[0109] (2) Preparation of calibration curve A sample of the compound of general formula (4) where n=4 (hereinafter also referred to as D4 form) (manufactured by Tokyo Chemical Industry Co., Ltd.) was measured into a 10 mL measuring flask, and using chloroform as a solvent, a sample with a D4 form concentration of 0.1 mg / mL and a sample with a D4 form concentration of 0.01 mg / mL were prepared. A liquid sampler was attached to the pyrolyzer set at 400°C, and 1μL of the above sample with adjusted concentration was measured with a microsyringe and injected into the pyrolyzer. While the pyrolyzer was heated to 400°C, the column was immersed in liquid nitrogen to trap the volatile components inside the column. One minute after the end of heating, the column was removed from the liquid nitrogen and GC / MS measurement was performed. A calibration curve was created using the concentration of D4 and the obtained peak area. The retention times of cyclic siloxanes in GC / MS measurements using the same equipment and measurement conditions are shown in Table 1. The same applies to subsequent GC / MS measurements.

[0110] [Table 1] In Table 1, Di (i=3 to 8) is a cyclic siloxane corresponding to i in the following general formula (8). Also, dimethyl j diphenyl 1 (j=2 to 6) in Table 1 is a cyclic siloxane corresponding to j in the following general formula (7). [ka] [ka]

[0111] (3) Analysis of the concentration of low molecular weight cyclic siloxane of general formula (4) in silicon-containing compounds The concentration of the low molecular weight cyclic siloxane of general formula (4) contained in SiDA was analyzed by heating SiDA to 100°C and measuring the resulting volatile components by GC / MS. A sample cup containing about 20 mg of SiDA was placed in the heating furnace (He atmosphere) of a pyrolyzer set at 100°C and heated at 100°C for 10 minutes. While the sample was heated at 100°C, the column was immersed in liquid nitrogen to trap the volatile components within the column. After heating, the sample cup was removed from the heating furnace, and after 1 minute, the column was removed from the liquid nitrogen and measured by GC / MS. The peak area of ​​each compound obtained was converted to the D4 concentration using a calibration curve prepared in advance. Table 11 shows the concentration of low molecular weight cyclic siloxanes (the total amount of r=3 to r=8 in the general formula (4) above, based on the silicon-containing compound) before and after the purification treatment of the silicon-containing compound described below.

[0112] (4) Analysis of the concentration of low molecular weight cyclic siloxane of general formula (4) in the solid content The concentration of the low molecular weight cyclic siloxane of general formula (4) contained in the solid content was calculated from the concentration of the low molecular weight cyclic siloxane of general formula (4) in the resin composition described below. That is, the total mass of the monomers used in the polyimide precursor of each Example and Comparative Example was taken as the mass of the solid content contained in the resin composition, and the concentration of the cyclic siloxane of general formula (4) in the solid content was calculated from the concentration of the cyclic siloxane of general formula (4) in the resin composition and its total mass. Table 11 shows the concentration of low molecular weight cyclic siloxanes (total amount of r=3 to r=8 in the general formula (4) above, on a solids basis) before and after the purification treatment of the silicon-containing compound described below.

[0113] (5) Analysis of the concentration of the low molecular weight cyclic siloxane of general formula (4) in the resin composition The analysis of the concentration of the cyclic siloxane of general formula (4) contained in the resin composition was performed under conditions simulating a pre-bake process in which precipitation of cyclic siloxane is a concern in a transparent polyimide process. The resin compositions of the examples and comparative examples were heated to 100°C, and the resulting volatile components were measured by GC / MS. The concentration of each compound was calculated from the peak area of ​​the measurement result of the volatile components of the resin composition. If the peak of each compound did not overlap with other compounds, the peak area calculated from the total ion chromatogram (TIC) was used. If it overlapped with other compounds, the peak area calculated from the mass chromatogram (MS) of m / z = 281 was used. A sample cup containing about 20 mg of the resin composition was placed in the heating furnace (He atmosphere) of a pyrolyzer set at 100°C, and heated at 100°C for 30 minutes. The resulting volatile components were measured by analyzing them with GC / MS. Using a calibration curve created in advance, the peak area of ​​each compound obtained was converted to the D4 isomer concentration. Table 11 shows the concentration of low molecular weight cyclic siloxanes (total amount of r=3 to r=8 in the general formula (4) above, based on the resin composition) before and after the purification treatment of the silicon-containing compound described below.

[0114] <Film evaluation YI (yellowness index)> In this evaluation, the difference in YI value between the polyimide resin films obtained by curing a polyimide precursor obtained using a purified silicon compound and a polyimide precursor obtained using an unpurified silicon compound was evaluated. The polyimide precursor composition of the example was applied to a 200 mm square alkali-free glass substrate (hereinafter also referred to as glass substrate) so that the film thickness after curing was 10 μm to form a coating film. The application was performed using a slit coater (TN25000, Tokyo Ohka Kogyo Co., Ltd.). One of the glass substrates having the obtained coating film of the polyimide precursor composition was dried in an oven (KLO-30NH, Koyo Thermo System) under a nitrogen atmosphere (oxygen concentration 300 ppm or less) at 100 ° C for 30 minutes to remove the solvent. Thereafter, it was heated under a nitrogen atmosphere (oxygen concentration 300 ppm or less) at 400 ° C for 1 hour to form a polyimide resin film on the glass substrate. Using the obtained polyimide resin film, the YI value was measured using a spectrophotometer (SE600) manufactured by Nippon Denshoku Industries Co., Ltd. A D65 light source was used as the light source. The difference in YI value was determined from the following formula. (Difference in YI value) = (YI value of the polyimide resin film obtained by curing the polyimide precursor using the unpurified silicon compound) - (YI value of the polyimide resin film obtained by curing the polyimide precursor using the purified silicon compound) In determining the difference in YI value, the curing of the polyimide precursor obtained using the unpurified silicon compound and the curing of the polyimide precursor obtained using the purified silicon compound were heat-treated in the same oven batch to eliminate equipment errors. The results are shown in Table 11.

[0115] <Rth (retardation, retardation in the thickness direction)> The polyimide precursor compositions of the examples and comparative examples were applied to a 200 mm square non-alkali glass substrate (hereinafter also referred to as a glass substrate) so that the film thickness after curing was 10 μm to form a coating film. The coating was performed using a slit coater (TN25000, Tokyo Ohka Kogyo Co., Ltd.). One of the glass substrates having the coating film of the obtained polyimide precursor composition was dried in an oven (KLO-30NH, Koyo Thermo System) at 100 °C for 30 minutes in a nitrogen atmosphere (oxygen concentration 300 ppm or less) to remove the solvent. Thereafter, it was heated at 400 °C for 1 hour in a nitrogen atmosphere (oxygen concentration 300 ppm or less) to form a polyimide resin film on the glass substrate. Regarding the polyimide film thus produced, Rth (converted to a film thickness of 10 μm) was measured using a phase difference birefringence measuring device (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.). The wavelength of the measurement light was 589 nm.

[0116] 《Purification method of silicon-containing compound》 The silicon-containing compounds described in the examples and comparative examples described below were treated by the following purification method to reduce the low molecular cyclic siloxanes contained therein. The concentration of the low molecular cyclic siloxanes after purification was analyzed by the above method. [Purification method] 10 kg of a silicon-containing compound was placed in a flask, and stripping was carried out at a temperature of 160° C. and a pressure of 270 Pa for 8 hours while blowing in nitrogen gas.

[0117] [Drying of monomer] Immediately after opening each monomer (acid dianhydride, diamine, silicon-containing compound), it was dried for more than 24 hours using a vacuum dryer (AVO-310NS, AS ONE) at 80°C and 2000-3000 Pa. After drying, it was used in the following synthesis within 1 hour.

[0118] [Examples and Comparative Examples (however, Example 1-1, Example 2-1, Example 3-1, Example 4-1, Example 5-1, Example 6-1, Example 7-1, Example 8-1, and Example 9-1 are reference examples.)] In each of the comparative examples described below, the monomers (acid dianhydride, diamine, silicon-containing compound) were used after being opened for at least one day, while in each of the examples, the monomers were used in synthesis immediately after being opened and subjected to the above-mentioned "monomer drying treatment." In each of the comparative examples described later, the solvents (NMP, GBL) used in the synthesis were left unsealed for at least one day, whereas in each of the examples described later, the solvents were used immediately after opening. In the tables described later, the silicon-containing compounds with the description "no treatment" in the purification treatment column were used as is without purification treatment, and those with the description "treated" were used after purification under the above purification conditions.

[0119] <Comparative Example 1-5> In a 3L separable flask with a stirring rod, NMP (201 g) was added while introducing nitrogen gas, TFMB (31.1 g) as a diamine, X-22-1660B-3 (13.20 g) as a silicon-containing compound were added while stirring, followed by BPAF (22.9 g) as an acid dianhydride and PMDA (10.9 g) (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80 ° C. using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used when evaluating. <Comparative Examples 1-1 to 1-4> The same procedure as in Comparative Example 1-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 2.

[0120] <Reference example 1-1> Comparative Example 1-5 was repeated, except that the amount of NMP was changed to 233 g, and the amounts of TFMB, X-22-1660B-3, BPAF, and PMDA were changed to those shown in Table 2 (molar ratio of dianhydride and diamine (100:99)). <Examples 1-2 and 1-3> Comparative Example 1-5 was repeated except that the amount of NMP was changed to 441 g, the amounts of TFMB, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 2 (molar ratio of dianhydride to diamine (100:99)), and the reaction conditions were changed to stirring at 40° C. for 12 hours.

[0121] <Example 1-4> The same procedure as in Example 1-2 was repeated, except that the synthesis solvent was changed to 220 g of NMP and 220 g of GBL. <Example 1-5> Comparative Example 1-5 was carried out in the same manner as Comparative Example 1-5, except that the amount of NMP was changed to 441 g, the amounts of TFMB, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 2 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at room temperature for 48 hours. <Examples 1-6> The same procedure as in Example 1-5 was carried out, except that X-22-1660B-3 in Example 1-5 was changed to that shown in Table 2. <Example 1-7> Comparative Example 1-5 was repeated, except that the amount of NMP was changed to 786 g, the amounts of TFMB, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 2 (molar ratio of dianhydride to diamine (100:99)), and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0122] <Comparative Example 2-5> In a 3L separable flask with a stirring rod, NMP (238 g) was added while introducing nitrogen gas, TFMB (30.9 g) as a diamine, X-22-1660B-3 (15.84 g) as a silicon-containing compound were added while stirring, and then BPAF (45.8 g) was added as an acid dianhydride (molar ratio of acid dianhydride to diamine (100:100)). Next, the temperature was raised to 80°C using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer, and was thawed and used when evaluating. <Comparative Examples 2-1 to 2-4> The same procedure as in Comparative Example 2-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 3.

[0123] <Reference example 2-1> Comparative Example 2-5 was repeated except that the amount of NMP was changed to 277 g, and the amounts of TFMB, X-22-1660B-3, and BPAF were changed to the amounts shown in Table 3 (molar ratio of dianhydride and diamine (100:99)). <Examples 2-2 and 2-3> Comparative Example 2-5 was carried out in the same manner as Comparative Example 2-5, except that the amount of NMP was changed to 522 g, the amount of X-22-1660B-3 was changed to that shown in Table 3, the amounts of TFMB, X-22-1660B-3, and BPAF were changed to those shown in Table 3 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40° C. for 12 hours. <Example 2-4> The same procedure as in Example 2-2 was repeated, except that the synthesis solvent was changed to 261 g of NMP and 261 g of GBL. <Example 2-5> The same procedure as in Reference Example 2-1 was repeated, except that the amount of NMP was changed to 933 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0124] <Comparative Example 3-5> In a 3L separable flask with a stirring rod, NMP (229 g) was added while introducing nitrogen gas, TFMB (30.9 g) as a diamine, X-22-1660B-3 (15.0 g) as a silicon-containing compound was added while stirring, and then BPAF-PA (32.1 g) and PMDA (10.9 g) were added as acid dianhydrides (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80 ° C. using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used when evaluating. <Comparative Examples 3-1 to 3-4> The same procedure as in Comparative Example 3-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 4.

[0125] <Reference example 3-1> Comparative Example 3-5 was repeated except that the amount of NMP was changed to 266 g, and the amounts of TFMB, X-22-1660B-3, BPAF-PA, and PMDA were changed to the amounts shown in Table 4 (molar ratio of dianhydride and diamine (100:99)). <Examples 3-2 and 3-3> Comparative Example 3-5 was carried out in the same manner as Comparative Example 3-5, except that the amount of NMP was changed to 502 g, the amount of X-22-1660B-3 was changed to that shown in Table 4, the amounts of TFMB, X-22-1660B-3, BPAF, and PMDA were changed to those shown in Table 4 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40°C for 12 hours. <Example 3-4> The same procedure as in Example 3-2 was repeated, except that the synthesis solvent was changed to 251 g of NMP and 251 g of GBL. <Example 3-5> The same procedure as in Reference Example 3-1 was repeated, except that the amount of NMP was changed to 896 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0126] <Comparative Example 4-5> In a 3L separable flask with a stirring rod, NMP (928g) was added while introducing nitrogen gas, 4,4'-DAS (24.2g) as a diamine, X-22-1660B-3 (11.88g) as a silicon-containing compound were added while stirring, followed by BPAF (22.9g) as an acid dianhydride and PMDA (10.9g) (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80°C using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used when evaluating. <Comparative Examples 4-1 to 4-4> The same procedure as in Comparative Example 4-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 5.

[0127] <Reference example 4-1> Comparative Example 4-5 was carried out in the same manner as Comparative Example 4-5, except that the amount of NMP was changed to 209 g, and the amounts of 4,4'-DAS, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 5 (molar ratio of dianhydride and diamine (100:99)). <Examples 4-2, 4-3, and 4-4> Comparative Example 4-5 was carried out in the same manner as Comparative Example 4-5, except that the amount of NMP was changed to 502 g, the amounts of 4,4'-DAS (or 3,3'-DAS), X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 5 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40°C for 12 hours. <Example 4-5> The same procedure as in Example 4-2 was repeated, except that the synthesis solvent was changed to 197 g of NMP and 197 g of GBL. <Examples 4-6> The same procedure as in Reference Example 4-1 was repeated, except that the amount of NMP was changed to 704 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0128] <Comparative Example 5-5> In a 3L separable flask with a stirring rod, NMP (209 g) was added while introducing nitrogen gas, FLDA (33.8 g) as a diamine, X-22-1660B-3 (13.64 g) as a silicon-containing compound were added while stirring, followed by BPAF (22.9 g) as an acid dianhydride and PMDA (10.9 g) (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80 ° C. using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used when evaluating. <Comparative Examples 5-1 to 5-4> The same procedure as in Comparative Example 5-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 6.

[0129] <Reference example 5-1> Comparative Example 5-5 was carried out in the same manner as Comparative Example 5-5, except that the amount of NMP was changed to 243 g, and the amounts of FLDA, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 6 (molar ratio of dianhydride and diamine (100:99)). <Examples 5-2 and 5-3> Comparative Example 5-5 was carried out in the same manner as in Comparative Example 5-5, except that the amount of NMP was changed to 458 g, the amounts of FLDA, X-22-1660B-3, BPAF, and PMDA were changed to the amounts shown in Table 6 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40° C. for 12 hours. <Example 5-4> The same procedure as in Example 5-2 was repeated, except that the synthesis solvent was changed to 229 g of NMP and 229 g of GBL. <Example 5-5> The same procedure as in Reference Example 5-1 was repeated, except that the amount of NMP was changed to 818 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0130] <Comparative Example 6-5> In a 3L separable flask with a stirring rod, NMP (152 g) was added while introducing nitrogen gas, CHDA (11.2 g) as a diamine, X-22-1660B-3 (10.12 g) as a silicon-containing compound was added while stirring, and then BPAF (22.9 g) and BPDA (14.7 g) were added as acid dianhydrides (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80 ° C. using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer, and was thawed and used when evaluating. <Comparative Examples 6-1 to 6-4> The same procedure as in Comparative Example 6-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 7.

[0131] <Reference example 6-1> Comparative Example 6-5 was repeated except that the amount of NMP was changed to 176 g, and the amounts of CHDA, X-22-1660B-3, BPAF, and BPDA were changed to the amounts shown in Table 7 (molar ratio of dianhydride and diamine (100:99)). <Examples 6-2 and 6-3> Comparative Example 6-5 was repeated except that the amount of NMP was changed to 332 g, the amounts of CHDA, X-22-1660B-3, BPAF, and BPDA were changed to the amounts shown in Table 7 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40° C. for 12 hours. <Example 6-4> The same procedure as in Example 6-2 was repeated, except that the synthesis solvent was changed to 166 g of NMP and 166 g of GBL. <Example 6-5> The same procedure as in Reference Example 6-1 was repeated, except that the amount of NMP was changed to 818 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0132] <Comparative Example 7-5> In a 3L separable flask with a stirring rod, NMP (201 g) was added while introducing nitrogen gas, BPAF (22.9 g) as a diamine, and KF-8012 (13.20 g) as a silicon-containing compound were added while stirring, followed by BPAF (22.9 g) and PMDA (10.9 g) as an acid dianhydride (molar ratio of acid dianhydride and diamine (100:100)). Next, the temperature was raised to 80 ° C. using an oil bath and stirred for 3 hours, after which the oil bath was removed and the temperature was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used for evaluation. <Comparative Examples 7-1 to 7-4> The same procedure as in Comparative Example 7-5 was repeated, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 8.

[0133] <Reference example 7-1> Comparative Example 7-5 was repeated, except that the amount of NMP was changed to 233 g, and the amounts of BPAF, KF-8012, BPAF, and PMDA were changed to those shown in Table 8 (molar ratio of dianhydride and diamine (100:99)). <Examples 7-2 and 7-3> Comparative Example 7-5 was repeated except that the amount of NMP was changed to 441 g, the amounts of BPAF, KF-8012, BPAF, and PMDA were changed to the amounts shown in Table 8 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40°C for 12 hours. <Example 7-4> The same procedure as in Example 7-2 was repeated, except that the synthesis solvent was changed to 220 g of NMP and 220 g of GBL. <Example 7-5> Comparative Example 7-5 was repeated except that the amount of NMP was changed to 441 g, and the amounts of TFMB, KF-8012, BPAF, and PMDA were changed to those shown in Table 8 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at room temperature for 48 hours. <Example 7-6> Comparative Example 7-5 was repeated except that the amount of NMP was changed to 786 g, and the amounts of TFMB, KF-8012, BPAF, and PMDA were changed to those shown in Table 8 (molar ratio of dianhydride to diamine (100:99)), and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0134] <Comparative Example 8-5> In a 3L separable flask with a stirring rod, NMP (201 g) was added while introducing nitrogen gas, and BPAF (22.2 g) was added as a diamine while stirring, followed by BPAF (22.2 g) as an acid dianhydride, PMDA (10.6 g), and X22-168-P5-B (13.44 g) as a silicon-containing compound (molar ratio of acid dianhydride and diamine (100:100)). Next, the mixture was heated to 80°C using an oil bath and stirred for 3 hours, after which the oil bath was removed and the mixture was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and was thawed and used for evaluation. <Comparative Examples 8-1 to 8-4> The same procedure as in Comparative Example 8-5 was repeated, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 9.

[0135] <Reference example 8-1> Comparative Example 8-5 was carried out in the same manner as Comparative Example 8-5, except that the amount of NMP was changed to 234 g, and the amounts of BPAF, X22-168-P5-B, BPAF, and PMDA were changed to the amounts shown in Table 9 (molar ratio of diamine to diamine (100:99)). <Examples 8-2 and 8-3> In Comparative Example 8-5, the amount of NMP was changed to 441 g, X22-168-P5-B was changed to that shown in Table 9, BPAF, X22-168-P5-B, BPAF, and PMDA were changed to the amounts shown in Table 9 (molar ratio of dianhydride and diamine (99:100)), and the reaction conditions were changed to stirring at 40 ° C. for 12 hours, except that Comparative Example 8-5 was repeated. <Example 8-4> The same procedure as in Example 8-2 was repeated, except that the synthesis solvent was changed to 222 g of NMP and 222 g of GBL. <Example 8-5> The same procedure as in Reference Example 8-1 was repeated, except that the amount of NMP was changed to 788 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0136] <Comparative Example 9-5> In a 3L separable flask with a stirring rod, NMP (200 g) was added while introducing nitrogen gas, and TFMB (32.0 g) was added as a diamine while stirring, followed by BPAF (22.0 g) as an acid dianhydride, PMDA (10.5 g), and X-22-168B (13.12 g) as a silicon-containing compound (molar ratio of acid dianhydride and diamine (100:100)). Next, the mixture was heated to 80°C using an oil bath and stirred for 3 hours, after which the oil bath was removed and the mixture was returned to room temperature to obtain a transparent NMP solution of polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer, and was thawed and used for evaluation. <Comparative Examples 9-1 to 9-4> The same procedure as in Comparative Example 9-5 was carried out, except that after stirring at 80° C. for 3 hours, NMP was added to adjust the solid content to that shown in Table 10.

[0137] <Reference example 9-1> Comparative Example 9-5 was repeated except that the amount of NMP was changed to 232 g, and the amounts of TFMB, X-22-168B, BPAF, and PMDA were changed to those shown in Table 10 (molar ratio of dianhydride and diamine (100:99)). <Examples 9-2 and 9-3> Comparative Example 9-5 was repeated except that the amount of NMP was changed to 438 g, the amounts of TFMB, X-22-168B, BPAF, and PMDA were changed to the amounts shown in Table 10 (molar ratio of dianhydride to diamine (99:100)), and the reaction conditions were changed to stirring at 40° C. for 12 hours. <Example 9-4> The same procedure as in Example 9-2 was repeated, except that the synthesis solvent was changed to 221 g of NMP and 221 g of GBL. <Example 9-5> The same procedure as in Reference Example 9-1 was repeated, except that the amount of NMP was changed to 781 g and the reaction conditions were changed to stirring at room temperature for 48 hours.

[0138] <Comparative Example 12-1> The same procedure as in Reference Example 1-1 was repeated, except that the amount of NMP was changed to 197 g and added, and the amounts of TFMB, X-22-1660B-3, and PMDA were changed to those shown in Table 12 (molar ratio of dianhydride and diamine (100:99)). <Comparative Example 12-2> The same procedure as in Example 1-7 was repeated, except that the amount of NMP was changed to 665 g and that the amounts of TFMB, X-22-1660B-3, and PMDA were changed to the amounts shown in Table 12 (molar ratio of dianhydride and diamine (100:99)).

[0139] [Table 2]

[0140] [Table 3]

[0141] [Table 4]

[0142] [Table 5]

[0143] [Table 6]

[0144] [Table 7]

[0145] [Table 8]

[0146] [Table 9]

[0147] [Table 10]

[0148] [Table 11]

[0149] [Table 12]

[0150] Explanation of abbreviations in the table <Acid dianhydride> BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride BPAF-PA: 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride PMDA: Pyromellitic dianhydride <Diamine> TFMB: 2,2'-diaminobis(trifluoromethyl)biphenyl 4,4'DAS: 4,4'-diaminodiphenyl sulfone; 3,3'DAS: 3,3'-diaminodiphenyl sulfone FLDA: 9,9-bis(4-aminophenyl)fluorene CHDA: 1,4-diaminocyclohexane <Silicon-containing compounds> X-22-1660B-3: Methylphenyl silicone oil modified with amino at both ends, functional group equivalent weight 2200, manufactured by Shin-Etsu Chemical Co., Ltd. KF-8012: Methyl silicone oil modified with amino at both ends, functional group equivalent 2200, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-168-P5-B: Methylphenyl silicone oil modified with carboxylic anhydrides at both ends, functional group equivalent 2100, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-168B: Methylphenyl silicone oil modified with carboxylic anhydrides at both ends, functional group equivalent 1600, manufactured by Shin-Etsu Chemical Co., Ltd. <Solvent> NMP: N-methyl-2-pyrrolidone GBL: gamma-butyrolactone [Explanation of symbols]

[0151] 2a Bottom Board 2b Sealing substrate 25 Organic EL structure 250a Red light emitting organic EL element 250b Green light-emitting organic electroluminescence element 250c Blue light emitting organic electroluminescence element 251 Partition (bank) 252 Lower electrode (anode) 253 Hole transport layer 254 Light-emitting layer 255 Upper electrode (cathode) 256 TFT 257 Contact Hole 258 Interlayer insulating film 259 Lower Electrode 261 Hollow part

Claims

1. The following formula (1): 【Chemistry 1】 {In the formula, P １ represents a divalent organic group, P １ When there are a plurality of groups, they may be the same or different; P ２ is expressed by the following formula (2): 【Chemistry 2】 (In the formula, Q １ and Q. ２ are each independently at least one selected from the group consisting of an alkyl group, an aryl group, an arylalkyl group, and a halogenated alkyl group; each X is independently at least one selected from the group consisting of -O-, -C(=O)-, -C(=O)O-, and -C(=O)NH-; each m and n is independently an integer of 0 to 2; and 1 is an integer of 0 or 1. P ２ When there are a plurality of, they may be the same or different, and p is a positive integer. The polyimide precursor is represented by the following formula (3): 【Chemistry 3】 {In the formula, P ３ and P ４ each independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms; P ３ When there are a plurality of groups, they may be the same or different; P ４ When there are a plurality of , they may be the same or different, and q is a positive integer. and the weight average molecular weight of the polyimide precursor is 90,000 to 250,000; The polyimide precursor is a copolymer of a tetracarboxylic dianhydride and a diamine, and the diamine is 4,4' and / or 3,3'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, and 1,4-Diaminocyclohexane A polyimide precursor comprising at least one selected from the group consisting of:

2. 2. The polyimide precursor of claim 1, wherein the weight average molecular weight of the polyimide precursor is greater than 96,000.

3. The tetravalent group represented by the formula (2) is 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, or 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride 3. The polyimide precursor according to claim 1, which is a residue of

4. The polyimide precursor according to any one of claims 1 to 3, wherein the tetracarboxylic dianhydride comprises at least one of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

5. The polyimide precursor according to any one of claims 1 to 4, wherein the polyimide precursor has a weight average molecular weight of 200,000 or less.

6. The polyimide precursor according to any one of claims 1 to 5, wherein the polyimide precursor has a weight average molecular weight of 110,000 to 200,000.

7. The polyimide precursor according to any one of claims 1 to 6, wherein the polyimide precursor has a weight average molecular weight of 180,000 or less.

8. The polyimide precursor according to any one of claims 1 to 7, wherein the polyimide precursor has a weight average molecular weight of 139,000 or more.

9. The polyimide precursor according to any one of claims 1 to 8; A solvent; A resin composition comprising:

10. The resin composition according to claim 9, wherein the solids content of the resin composition is 9 to 25% by weight, 9 to 20% by weight, 9 to 15% by weight, or 9 to 13% by weight.

11. The resin composition according to claim 9 or 10, wherein a polyimide resin film which is a cured product of the polyimide precursor is used for a flexible substrate.

12. The resin composition according to any one of claims 9 to 11, wherein a polyimide resin film which is a cured product of the polyimide precursor is used for a flexible display.

13. A coating step of coating the resin composition according to any one of claims 9 to 12 on a surface of a support; a film-forming step of heating the resin composition to form a polyimide resin film; a peeling step of peeling the polyimide resin film from the support; A method for producing a polyimide film comprising the steps of:

14. The method for producing a polyimide film according to claim 13, further comprising, prior to the peeling step, an irradiation step of irradiating the resin composition with a laser from the support side.

15. A coating step of coating the resin composition according to any one of claims 9 to 12 on a surface of a support; a film-forming step of heating the resin composition to form a polyimide resin film; an element forming step of forming an element on the polyimide resin film; a peeling step of peeling the polyimide resin film on which the elements are formed from the support; A method for manufacturing a display comprising:

16. A coating step of coating the resin composition according to any one of claims 9 to 12 on a surface of a support; a film-forming step of heating the resin composition to form a polyimide resin film; an element forming step of forming an element on the polyimide resin film; A method for producing a laminate, comprising:

17. The method for producing a laminate according to claim 16 , further comprising the step of peeling off the polyimide resin film on which the elements are formed from the support.

18. A method for producing a flexible device, comprising producing a laminate by the method for producing a laminate according to claim 16 or 17.

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