Polyimide precursor and polyimide resin composition

Abstract

To provide a composition which can achieve excellent results of each of above evaluations compared to a case in which an unpurified siloxane compound is used, and partially has a polyimide precursor (PAI) having an imide group, and a polyimide film obtained by heating the composition.SOLUTION: A resin composition includes a polyimide precursor that includes a structural unit represented by a specific general formula and is partially imidized, and a compound represented by the following general formula (3). The total amount of the compounds having n of 4 in the following general formula (3) is more than 0 ppm and 120 ppm or less based on the mass of the resin composition, or the total amount of the compounds having n of 5 in the following general formula (3) is 0 ppm or more and 50 ppm or less based on the mass of the resin composition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polyimide precursor resin composition, a polyimide resin composition, and methods for producing them. The present invention also relates to methods for producing a polyimide film, a display, a laminate, and a flexible device using the polyimide precursor resin composition and the polyimide resin composition. [Background technology]

[0002] Polyimide resins are insoluble, infusible, and extremely heat-resistant resins with excellent properties, including thermal oxidation resistance, heat resistance, radiation resistance, low temperature resistance, and chemical resistance. For this reason, polyimide resins are used in a wide range of fields, including electronic materials. Examples of applications of polyimide resins in the electronic materials field include insulating coatings, insulating films, semiconductors, and electrode protection films for thin-film transistor liquid crystal displays (TFT-LCDs). Recently, taking advantage of the lightness and flexibility of polyimide films, their use as flexible substrates has been considered in the display materials field, replacing the glass substrates traditionally used.

[0003] For example, Patent Document 1 describes a resin precursor (weight average molecular weight 30,000 to 90,000) polymerized from bis(diaminodiphenyl)sulfone (hereinafter also referred to as DAS) and containing siloxane units. Patent Document 1 also describes that a polyimide obtained by curing the precursor has low residual stress generated between the precursor and a support such as glass, excellent chemical resistance, and little effect of oxygen concentration during the curing process on yellowness index (YI value) and total light transmittance. Patent Document 2 describes a resin precursor polymerized from 2,2'-bis(trifluoromethyl)benzidine (hereinafter also referred to as TFMB) and containing siloxane units. Patent Document 2 also describes that a polyimide film obtained by curing the precursor has a specific glass transition temperature, low residual stress generated between the precursor and an inorganic film, and excellent mechanical properties and thermal stability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 148441 [Patent Document 2] International Publication No. 2014 / 098235 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-029126 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-028533 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-012666 [Patent Document 6] International Publication No. 2019 / 208587 [Patent Document 7] Japanese Patent Application Publication No. 2019-203117 [Patent Document 8] Japanese Patent Application Publication No. 9-263636 [Patent Document 9] International Publication No. 2020 / 138360 [Non-patent literature]

[0005] [Non-Patent Document 1] Shin-Etsu Chemical Co., Ltd. website, "Q&A", "About Silicone Grease and Oil Compounds", [online], [Retrieved November 26, 2020], Internet<URL:https: / / www.silicone.jp / contact / qa / qa103.shtml> Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Documents 1 and 2 use a siloxane-containing compound as a monomer for a polyimide precursor, but such a siloxane-containing compound contains a low-molecular-weight cyclic siloxane (hereinafter also referred to as a low-molecular-weight cyclic siloxane). Because this low-molecular-weight cyclic siloxane is volatile, it is known to generate outgassing, which may cause contact failures in the manufacturing equipment used in the process. For example, see Non-Patent Document 1.

[0007] Prior art documents relating to polyimide precursors in which the low molecular weight cyclic siloxane content has been reduced by purification include Patent Documents 3 to 5. Patent Document 3 describes adding a siloxane-containing compound to acetone, followed by centrifugation and decantation to remove the low molecular weight cyclic siloxane, and describes that the resulting polyimide has transparency and little outgassing. Patent Documents 4 and 5 describe purifying the siloxane-containing compound by stripping it under specific conditions or by dissolving it in 2-butanone and reprecipitating it with methanol, and describe that the resulting polyimide has improved adhesion.

[0008] The present inventors synthesized polyimide precursors and polyimides using siloxane-containing compounds purified by the same purification methods as those described in Patent Documents 3 to 5, and then produced polyimide films using them. As a result, they found that the storage stability of the resin composition, the repelling of coating films, and the in-plane uniformity of the retardation (Rth) of the polyimide resin film were all insufficient when the resin composition was repeatedly frozen and left at room temperature. Therefore, the present invention aims to provide a composition containing a polyimide precursor (PAI) partially containing imide groups, which can achieve excellent results in each of the above evaluations compared to when an unpurified siloxane compound is used, and a polyimide film obtained by heating the composition. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the purification methods described in the above-mentioned prior art documents do not sufficiently reduce some of the compounds of general formula (3). They have then found that the above-mentioned problems can be solved by further purifying the silicon-containing compound, reducing some of the compounds of general formula (3) to a specific amount, and using this as a raw material to produce a PAI of a specific structure. Examples of embodiments of the present invention are listed below in [1] to

[35] . [1] a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: The total amount of compounds in which n is 4 in the following general formula (3) is more than 0 ppm and 120 ppm or less based on the mass of the resin composition, or A resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 5 is more than 0 ppm and not more than 50 ppm based on the mass of the resin composition: [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r represents an integer of 1 to 200.} [ka] {wherein n is an integer of 2 or more.} [2] The total amount of the compounds of the general formula (3) in which n is 4 is more than 0 ppm and 70 ppm or less based on the mass of the resin composition, or Item 2. The resin composition according to item 1, wherein the total amount of the compound of general formula (3) where n is 5 is more than 0 ppm and 30 ppm or less, based on the mass of the resin composition. [3] The total amount of the compounds of the general formula (3) in which n is 4 is more than 0 ppm and 30 ppm or less based on the mass of the resin composition, or Item 3. The resin composition according to item 2, wherein the total amount of the compound of general formula (3) where n is 5 is more than 0 ppm and 15 ppm or less, based on the mass of the resin composition. [4] a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: The resin composition comprises the following: the polyimide precursor is produced by a method comprising: subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then further subjecting the polyimide precursor to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to provide a partially imidized polyimide precursor; or subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then further subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to provide a partially imidized polyimide precursor; The total amount of compounds of the following general formula (3) in which n is 4 contained in the raw material composition is more than 0 ppm and 1300 ppm or less based on the total mass of the silicon-containing compounds represented by the following general formulas (3) and (4), or A resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 5 contained in the raw material composition is more than 0 ppm and 500 ppm or less, based on the total mass of the silicon-containing compounds of the general formulas (3) and (4): [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r represents an integer of 1 to 200.} [ka] {wherein n is an integer of 2 or more.} [ka] {In the formula, each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms; each R2 and R3 is 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; each R4 and R5 is independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; each R6 and R7 is independently a monovalent organic group having 1 to 10 carbon atoms; each L1 and L2 is independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; each j and k is independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.} [5] The total amount of the compound of general formula (3) in which n is 4 contained in the raw material composition is more than 0 ppm and 800 ppm or less based on the total mass of the silicon-containing compounds represented by general formulas (3) and (4), or 5. The resin composition according to item 4, wherein the total amount of the compound of general formula (3) where n is 5 contained in the raw material composition is more than 0 ppm and 300 ppm or less, based on the total mass of the silicon-containing compounds of general formulas (3) and (4). [6] The total amount of the compound of general formula (3) in which n is 4 contained in the raw material composition is more than 0 ppm and 30 ppm or less based on the total mass of the silicon-containing compounds represented by general formulas (3) and (4), or 5. The resin composition according to item 4, wherein the total amount of the compound of general formula (3) where n is 5 contained in the raw material composition is more than 0 ppm and 15 ppm or less, based on the total mass of the silicon-containing compounds of general formulas (3) and (4). [7] a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: A resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 3 or more and 8 or less is more than 0 ppm and 150 ppm or less based on the mass of the resin composition: [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r represents an integer of 1 to 200.} [ka] {wherein n is an integer of 2 or more.} [8] a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: A resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 3 or more and 8 or less is more than 0 ppm and 900 ppm or less, based on the mass of the non-solvent components of the resin composition: [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r represents an integer of 1 to 200.} [ka] {wherein n is an integer of 2 or more.} [9] a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: The resin composition comprises the following: The polyimide precursor is produced by a method comprising: subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then subjecting the raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then subjecting the raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to provide a partially imidized polyimide precursor; A resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 3 or more and 8 or less contained in the raw material composition is more than 0 ppm and 4500 ppm or less based on the total mass of silicon-containing compounds represented by the following general formulas (3) and (4): [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r represents an integer of 1 to 200.} [ka] {wherein n is an integer of 2 or more.} [ka] {In the formula, each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms; each R2 and R3 is 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; each R4 and R5 is independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; each R6 and R7 is independently a monovalent organic group having 1 to 10 carbon atoms; each L1 and L2 is independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; each j and k is independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.}

[10] 10. The resin composition according to any one of items 1 to 9, wherein p and q satisfy 20≦q / (p+q)×100≦80.

[11] The resin composition according to any one of items 4 to 6 and 9, wherein L1 and L2 in the silicon-containing compound represented by the general formula (4) are each independently selected from the group consisting of an amino group, an acid anhydride group, an epoxy group, a hydroxy group, and a mercapto group.

[12] 10. The resin composition according to any one of items 4 to 6 and 9, wherein L1 and L2 in the silicon-containing compound represented by general formula (4) are amino groups.

[13] 10. The resin composition according to any one of items 4 to 6 and 9, wherein the functional group equivalent of the silicon-containing compound represented by general formula (4) is 800 or more.

[14] The resin composition according to any one of items 4 to 6, 9, and 11 to 13, wherein the tetracarboxylic dianhydride is at least one selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 4,4'-oxydiphthalic anhydride (ODPA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), and p-phenylenebis(trimellitate anhydride) (TAHQ).

[15] The resin composition according to any one of items 4 to 6, 9, and 11 to 14, wherein the diamine is at least one selected from the group consisting of 4,4'-diaminodiphenyl sulfone (4,4'-DAS), 3,3'-bis(diaminodiphenyl)sulfone (3,3'-DAS), 9,9-bis(4-aminophenyl)fluorene (BAFL), diaminobis(trifluoromethyl)biphenyl (TFMB), 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and 1,3-bis(aminomethyl)cyclohexane (BAC).

[16] 16. The resin composition according to any one of items 1 to 15, wherein a polyimide resin film obtained by curing the resin composition is used for a flexible substrate.

[17] 16. The resin composition according to any one of items 1 to 15, wherein a polyimide resin film obtained by curing the resin composition is used for a flexible display.

[18] A method for producing a resin composition, comprising: subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the composition and obtain a polyimide; and then further subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the composition and obtain a polyimide; and then further subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to obtain a polyimide and then further subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the composition and obtain a polyimide; The resin composition may contain a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3), and the total amount of the compounds represented by the following general formula (3) in which n is 4 contained in the raw material composition is more than 0 ppm and not more than 1300 ppm based on the total mass of the silicon-containing compounds represented by the following general formulas (3) and (4), or A method for producing a resin composition, wherein the total amount of compounds of the following general formula (3) in which n is 5 contained in the raw material composition is more than 0 ppm and 500 ppm or less based on the total mass of the silicon-containing compounds of the general formulas (3) and (4): [ka] {wherein n is an integer of 2 or more.} [ka] wherein each R1 independently represents a single bond or a divalent organic group having 1 to 10 carbon atoms; R2 and R3 are 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; R4 and R5 are each independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; R6 and R7 are each independently a monovalent organic group having 1 to 10 carbon atoms; L1 and L2 are each independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; j and k are each independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.}

[19] The total amount of the compound of general formula (3) in which n is 4 contained in the raw material composition is more than 0 ppm and 800 ppm or less based on the total mass of the silicon-containing compounds represented by general formulas (3) and (4), or Item 19. The method for producing a resin composition according to Item 18, wherein the total amount of the compound of general formula (3) in which n is 6 contained in the raw material composition is more than 0 ppm and 300 ppm or less, based on the total mass of the silicon-containing compounds of general formulas (3) and (4).

[20] A method for producing a resin composition, comprising: subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then further subjecting the raw material composition to a polycondensation reaction with the tetracarboxylic dianhydride and a diamine to provide a polyimide precursor which is partially imidized and has imide groups in some portions; or subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with the tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then further subjecting the raw material composition to a polycondensation reaction with the tetracarboxylic dianhydride and a diamine to provide a polyimide precursor which is partially imidized and has imide groups in some portions; The resin composition may contain a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3), and the total amount of the compounds represented by the following general formula (3) where n is 3 or more and 8 or less contained in the raw material composition is more than 0 ppm and 4500 ppm or less based on the total mass of the silicon-containing compounds represented by the following general formulas (3) and (4). [ka] {wherein n is an integer of 2 or more.} [ka] {In the formula, each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms; each R2 and R3 is 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; each R4 and R5 is independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; each R6 and R7 is independently a monovalent organic group having 1 to 10 carbon atoms; each L1 and L2 is independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; each j and k is independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.} [twenty one] 21. The method for producing a resin composition according to any one of items 18 to 20, wherein the functional group equivalent of the silicon-containing compound represented by general formula (4) is 800 or more. [twenty two] A method for producing a resin composition, comprising: subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the composition and obtain a polyimide, and then further subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to obtain a partially imidized polyimide precursor; or subjecting a raw material composition containing a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3) to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to imidize the polyimide, and then further subjecting the raw material composition to a polycondensation reaction with a tetracarboxylic dianhydride and a diamine to partially imidize the polyimide precursor and obtain a partially imidized polyimide precursor, The resin composition may contain a silicon-containing compound represented by the following general formula (4) and a compound represented by the following general formula (3), and the method includes a step of reducing the total amount of compounds in which n is 5, or the total amount of compounds in which n is 6, or the total amount of compounds in which n is 7, based on the total mass of the silicon-containing compounds of the following general formulas (4) and (3), The method, wherein the reducing step comprises treating the composition at 150 to 300°C and 300 Pa or less for 2 to 12 hours. [ka] {wherein n is an integer of 2 or more.} [ka] {In the formula, each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms; each R2 and R3 is 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; each R4 and R5 is independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; each R6 and R7 is independently a monovalent organic group having 1 to 10 carbon atoms; each L1 and L2 is independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; each j and k is independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.} [twenty three] 23. The method according to any one of items 18 to 22, wherein L1 and L2 in the silicon-containing compound represented by general formula (4) are each independently selected from the group consisting of an amino group, an acid anhydride group, an epoxy group, a hydroxy group, and a mercapto group. [twenty four] 23. The method according to any one of items 18 to 22, wherein L1 and L2 in the silicon-containing compound represented by general formula (4) are amino groups. [twenty five] 25. The method according to any one of Items 18 to 24, wherein the tetracarboxylic dianhydride is at least one selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 4,4'-oxydiphthalic anhydride (ODPA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA).

[26] 26. The method according to any one of items 18 to 25, wherein the diamine is at least one selected from the group consisting of 4,4'-diaminodiphenyl sulfone (4,4'-DAS), 3,3'-bis(diaminodiphenyl) sulfone (3,3'-DAS), 9,9-bis(4-aminophenyl)fluorene (BAFL), 2,2'-dimethylbenzidine (mTB), p-phenylenediamine (PDA), diaminobis(trifluoromethyl)biphenyl (TFMB), 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 4,4'-diaminodiphenyl ether (ODA), and 1,4-cyclohexanediamine (CHDA).

[27] A coating step of coating the resin composition according to any one of items 1 to 17 onto 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:

[28] Item 28. The method for producing a polyimide film according to Item 27, further comprising, prior to the peeling step, irradiating the resin composition with a laser from the support side.

[29] A coating step of coating the resin composition according to any one of items 1 to 17 onto 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 element is formed from the support; A method for manufacturing a display, comprising:

[30] A coating step of coating the resin composition according to any one of items 1 to 17 onto 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:

[31] Item 31. The method for producing a laminate according to Item 30, further comprising the step of peeling off the polyimide resin film on which the element is formed from the support.

[32] Item 32. A method for producing a flexible device, comprising producing a laminate by the method according to Item 30 or 31.

[33] 18. A polyimide film that is a cured product of the resin composition according to any one of items 1 to 17.

[34] A resin composition comprising a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2): [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} A resin composition, wherein P9 is a group derived from 9,9-bis(3,4-dicarboxyphenyl)fluorene diacid anhydride (BPAF) or p-phenylene bis(trimellitate anhydride) (TAHQ).

[35] A resin composition comprising a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2): [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} A resin composition, wherein P8 is a group derived from one or more compounds selected from 4,4'-diaminodiphenyl sulfone (4,4'-DAS), 3,3'-bis(diaminodiphenyl) sulfone (3,3'-DAS), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and p-phenylene bis(trimellitate anhydride) (TAHQ). [Effects of the Invention]

[0010] According to the present invention, a silicon-containing compound of a specific structure is used, purified under specific conditions, and then the silicon-containing compound is used to form a polyimide precursor (PAI) structure having imide groups in part. This makes it possible to provide a resin composition and a polyimide film that can simultaneously evaluate the storage stability of the resin composition, the repellency of coating films, and the in-plane uniformity of the retardation (Rth) of the polyimide resin film. The above description should not be construed as disclosing all embodiments and advantages of the present invention. Further embodiments and advantages of the present invention will become apparent from the following description. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the structure of a top-emission flexible organic EL display above a polyimide substrate, as an example of the display of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0013] 《Resin composition》 <Polyimide precursor and polyimide> Structural units of general formulae (1-1) and (1-2) The resin composition of the present embodiment can contain a partially imidized polyimide precursor (hereinafter also referred to as PAI) that includes a structural unit represented by the following general formula (1-1) and a structural unit represented by the following general formula (1-2).

[0014] [ka] {In the formula, P1 represents a divalent organic group, P2 represents a tetravalent organic group, and p represents a positive integer.} [ka] {In the formula, P8 represents a divalent organic group, P9 represents a tetravalent organic group, and q represents a positive integer.} Thus, by having both a polyimide precursor structure and a polyimide structure, it is possible to achieve both of their respective advantages. Specifically, the polyimide precursor is preferred because it has excellent solvent solubility, coating film repellency, etc., while the polyimide is preferred because it has excellent viscosity stability of the composition and storage stability when the composition is stored at low temperature or room temperature.

[0015] Here, P2 and P9 groups are acid anhydride residues and may be the same or different, and P1 and P8 groups are diamine residues and may be the same or different.

[0016] The proportion of the polyimide structure, i.e., the value of q / (p+q)×100, is preferably greater than 0 and equal to or less than 80, more preferably equal to or greater than 20 and equal to or less than 80. When the proportion of the polyimide structure is within this range, it is possible to simultaneously evaluate the storage stability of the resin composition, the coating repellency, and the in-plane uniformity of Rth of the polyimide film.

[0017] The larger the proportion of the polyimide structure (the smaller the proportion of the polyimide precursor structure), the better the storage stability of the composition described below, which is preferable. Although the reason for this is unclear, it is thought that the polyimide precursor structure is more likely to decompose into monomers (acid dianhydride, diamine) than the polyimide structure, especially when the resin composition is stored at room temperature.

[0018] On the other hand, the larger the proportion of the polyimide precursor structure (the smaller the proportion of the polyimide structure), the better the coating film repellency evaluation described below, which is preferable. The reason for this is unclear, but it is thought that the resin composition is applied to a glass substrate, and hydroxyl groups are present on the surface of the glass substrate. In the case of the polyimide precursor structure, the amide group and carboxyl group have a high affinity with the hydroxyl group, which is thought to be why the repellency evaluation was good.

[0019] acid dianhydride In the general formulas (1-1) and (1-2), examples of the acid dianhydride containing a P2 group or a P9 group include pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2 dicarboxylic anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenone 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 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 hydrate, 4,4'-oxydiphthalic dianhydride, p-phenylenebis(trimellitate anhydride), thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride Propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), bicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride (CpODA), 4,4'-oxydiphthalic anhydride (ODPA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), etc.

[0020] The acid dianhydride is preferably at least one selected from the group consisting of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), 4,4'-oxydiphthalic anhydride (ODPA), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), p-phenylenebis(trimellitate anhydride) (TAHQ), and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA).

[0021] The acid dianhydrides may be used alone or in combination of two or more. Among these, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), pyromellitic dianhydride (PMDA), p-phenylenebis(trimellitate anhydride) (TAHQ), and biphenyltetracarboxylic dianhydride (BPDA) are preferred in terms of the mechanical properties of the polyimide film, optical properties such as low thickness retardation (Rth) and low YI value, and high glass transition temperature. The polyimide precursor having a structure represented by general formula (1-1) and the polyimide having a structure represented by general formula (1-2) are copolymers of tetracarboxylic dianhydride and diamine, and the tetracarboxylic dianhydride preferably includes 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF).

[0022] The content of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) in the total acid dianhydrides is preferably 60 mol % or more, more preferably 80 mol % or more, and even more preferably 100 mol % from the viewpoints of low Rth and YI values ​​and a high glass transition temperature of the polyimide film.

[0023] Diamine In the general formulas (1-1) and (1-2), examples of diamines containing a P1 group or a P8 group include diaminodiphenyl sulfone (e.g., 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone), p-phenylenediamine (PDA), m-phenylenediamine, 2,2'-dimethylbenzidine (mTB), 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, and 4,4'-diaminobiphenyl. , 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy) )phenyl)]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl) Examples of suitable fluorocarbons include hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, and 1,4-bis(3-aminopropyldimethylsilyl)benzene, 9,9-bis(4-aminophenyl)fluorene (BAFL), 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), and p-phenylenebis(trimellitate anhydride) (TAHQ).

[0024] The diamine is preferably at least one selected from the group consisting of 4,4'-diaminodiphenyl sulfone (4,4'-DAS), 3,3'-bisdiaminodiphenyl sulfone (3,3'-DAS), 9,9-bis(4-aminophenyl)fluorene (BAFL), and 1,4-cyclohexanediamine (CHDA).

[0025] The diamine preferably includes diaminodiphenyl sulfone, for example, 4,4'-diaminodiphenyl sulfone (4,4'-DAS) and / or 3,3'-diaminodiphenyl sulfone (3,3'-DAS).

[0026] From the viewpoint of the in-plane uniformity of the Rth in the thickness direction of the obtained polyimide resin film, it is more preferable that the diamine is at least one selected from the group consisting of 4,4'-diaminodiphenylsulfone (4,4'-DAS), 3,3'-diaminodiphenylsulfone (3,3'-DAS), and 9,9-bis(4-aminophenyl)fluorene (BAFL).

[0027] The content of diaminodiphenyl sulfone in all diamines may be 50 mol% or more, 70 mol% or more, 90 mol% or more, or 95 mol% or more. A larger amount of diaminodiphenyl sulfone is preferable because it reduces the YI value of the polyimide film and enables a higher glass transition temperature to be obtained. As the diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone is particularly preferable from the viewpoint of reducing the YI value.

[0028] The diamine may be used alone or in combination of two or more. It is preferable to copolymerize diaminodiphenyl sulfone with other diamines. From the viewpoints of high heat resistance and a low YI value of the polyimide film, the other diamine to be copolymerized with diaminodiphenyl sulfone is preferably a diamido biphenyl, more preferably diaminobis(trifluoromethyl)biphenyl (TFMB). The content of diaminobis(trifluoromethyl)biphenyl (TFMB) in all diamines is preferably 20 mol% or more, more preferably 30 mol% or more, from the viewpoint of a low YI value of the polyimide film. From the viewpoint of designing the diamine so that it can contain other advantageous diamines such as diaminodiphenyl sulfone, the content of TFMB in all diamines is preferably 80 mol% or less, more preferably 70 mol% or less.

[0029] Structural unit of general formula (2) The polyimide precursor and polyimide in the resin composition of this embodiment further contain a structural unit represented by the following general formula (2).

[0030] [ka] {In the formula, P3 and P4 each independently represent a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms, and r is an integer from 1 to 200. P3 and P4 each independently represent preferably a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms, more preferably a monovalent aliphatic hydrocarbon having 1 to 3 carbon atoms, and even more preferably a methyl group.}

[0031] Based on the mass of the polyimide precursor or polyimide, the lower limit of the ratio of the structural moiety represented by general formula (2) 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 residual stress in the polyimide film generated between the polyimide precursor or polyimide and the support. Based on the mass of the polyimide precursor or polyimide, the upper limit of the ratio of the structural moiety represented by general 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 transparency and heat resistance of the polyimide film. In the above general formula (2), r is an integer of 1 to 200, and from the viewpoint of heat resistance of the resulting polyimide, an integer of 3 to 200 is preferred.

[0032] The polyimide precursor and polyimide may have the structure of general formula (2) at any position in the molecule. The structure of general formula (2) is preferably a structure derived from a silicon-containing compound represented by general formula (4) described below.

[0033] In the general formula (2), P3 and P4 are preferably aliphatic groups (specifically, methyl groups) rather than aromatic groups (specifically, phenyl groups), because this improves the storage stability of the resin composition described below. The reason for this is unclear, but it is presumed that when the composition is stored at room temperature, the polyimide precursor structure may decompose into its respective monomers, and the decomposed silicon-containing monomers tend to aggregate more easily if they contain phenyl groups than if they contain methyl groups, resulting in poor storage stability.

[0034] dicarboxylic acids In this embodiment, the acid component for forming the polyimide precursor and polyimide may be a dicarboxylic acid in addition to an acid dianhydride (e.g., the tetracarboxylic dianhydride exemplified above), provided that the performance is not impaired. That is, the polyimide precursor of the present disclosure may be a polyamideimide precursor, and the polyimide may be a polyamideimide. Polyimide films obtained from such polyimide precursors or polyimides may exhibit excellent performance characteristics, such as mechanical elongation, glass transition temperature (Tg), and YI value. Examples of dicarboxylic acids 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 preferred. The carbon number referred to here includes the number of carbon atoms contained in the carboxyl group. Among these, dicarboxylic acids having an aromatic ring are preferred.

[0035] 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, and 3,3'-oxybisbenzoic acid. 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 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 5-aminoisophthalic acid derivatives described in WO 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.

[0036] The polyimide precursor and polyimide in the resin composition of this embodiment can also be described as a copolymer containing a silicon-containing compound, a tetracarboxylic dianhydride, and a diamine as monomer units. In this case, the silicon-containing compound may contain compounds of the following general formula (4), general formula (3), and / or general formula (5). The silicon-containing compound may be synthesized using the common general technical knowledge at the time of filing, or a commercially available product may be used. The synthesized silicon-containing compound or a commercially available silicon-containing compound may be purified as described below and then used as a monomer unit of the polyimide precursor and polyimide.

[0037] [ka] {In the formula, each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms; each R2 and R3 is 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; each R4 and R5 is independently a monovalent organic group having 1 to 10 carbon atoms, at least one of which is a monovalent aromatic group having 6 to 10 carbon atoms; each R6 and R7 is independently a monovalent organic group having 1 to 10 carbon atoms; each L1 and L2 is independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group; i is an integer of 1 to 200; each j and k is independently an integer of 0 to 200, and 0≦j / (i+j+k)≦0.50.}

[0038] L1 and L2 of the silicon-containing compound represented by the general formula (4) are not limited, but are each preferably independently an amino group, an acid anhydride group, an isocyanate group, a carboxyl group, an acid ester group, an acid halide group, a hydroxy group, an epoxy group, or a mercapto group. From the viewpoint of the molecular weight of the resulting polyimide precursor and polyimide, L1 and L2 are preferably selected from the group consisting of an amino group, an acid anhydride group, an epoxy group, a hydroxy group, and a mercapto group, and more preferably an amino group.

[0039] The functional group equivalent of the silicon-containing compound represented by the general formula (4) is preferably 800 or more, more preferably 1500 or more, from the viewpoint of the heat resistance (glass transition temperature) and residual stress of the resulting polyimide film. Here, the functional group equivalent is the molecular weight of the silicon-containing compound per 1 mole of functional group (unit: g / mol). Examples of functional groups include amino groups, acid anhydride groups, isocyanate groups, carboxyl groups, acid ester groups, acid halide groups, hydroxy groups, epoxy groups, and mercapto groups. The functional group equivalent can be measured by the method described in the Examples. When the functional group equivalent of the silicon-containing compound is 800 or more, the silicone domains increase, resulting in stress relaxation, and therefore, it is believed that the residual stress of the polyimide film is reduced.

[0040] In general formula (4), each R1 is independently a single bond or a divalent organic group having 1 to 10 carbon atoms. The divalent organic group having 1 to 10 carbon atoms may be 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; and cycloalkylene groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, and cyclooctylene. The divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of ethylene, n-propylene, and i-propylene.

[0041] In general formula (4), R2 and R3 are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. Examples of the monovalent organic group having 1 to 10 carbon atoms 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; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl. The monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. Examples of the monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and neopentyl groups; and cycloalkyl groups such as cyclopropyl, cyclobutyl, and cyclopentyl groups. 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, and more preferably methyl.

[0042] In general formula (4), R4 and R5 are each independently a monovalent organic group having 1 to 10 carbon atoms, and at least one is a monovalent aromatic group having 6 to 10 carbon atoms. The monovalent organic group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and may be saturated or unsaturated. Examples of the monovalent organic group having 1 to 10 carbon atoms 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; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl. Examples of the monovalent aromatic group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl groups, and phenyl, tolyl, or xylyl is preferred.

[0043] In general formula (4), R6 and R7 are each independently a monovalent organic group having 1 to 10 carbon atoms, and may be an organic group partially containing 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; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and aromatic groups such as phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl. The monovalent organic group having 1 to 10 carbon atoms is preferably at least one selected from the group consisting of methyl, ethyl, and phenyl. The organic group having an unsaturated aliphatic hydrocarbon group may be an unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, and may be 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.

[0044] In general formula (4), some or all of the hydrogen atoms of R1 to R7 may be substituted with a substituent such as a halogen atom, eg, F, Cl, or Br, or may be unsubstituted.

[0045] i is an integer of 1 to 200, preferably an integer of 2 to 100, more preferably an integer of 4 to 80, and even more preferably an integer of 8 to 40. j and k are each independently an integer of 0 to 200, preferably an integer of 0 to 50, more preferably an integer of 0 to 20, and even more preferably an integer of 0 to 50.

[0046] From the viewpoints of the type of monomer, cost, and the molecular weight of the resulting polyimide precursor and polyimide, the silicon-containing compound of general formula (4) is preferably a silicon-containing diamine. As the silicon-containing diamine, for example, a diamino(poly)siloxane represented by the following formula (6) is preferred.

[0047] [ka] {In the formula, P5s each independently represent a divalent hydrocarbon group and may be the same or different, P3 and P4 are the same as defined in general formula (2), and 1 represents an integer of 1 to 200.}

[0048] Preferred structures of P3 and P4 in the general formula (2) include a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group. Among these, a methyl group is preferred. In the general formula (6), l is an integer of 1 to 200, and from the viewpoint of the heat resistance of the resulting polyimide, an integer of 3 to 200 is preferred.

[0049] The preferred range of the functional group equivalent weight of the compound represented by general formula (6) is 800 or more, and more preferably 1500 or more, similar to the silicon-containing compound represented by general formula (4) described above.

[0050] The copolymerization ratio of the silicon-containing diamine is preferably 0.5 to 30% by mass, more preferably 1.0 to 25% by mass, and even more preferably 1.5 to 20% by mass, based on the total mass of the polyimide precursor or polyimide. When the silicon-containing diamine is 0.5% by mass or more, residual stress generated between the support and the polyimide can be effectively reduced. When the silicon-containing diamine is 30% by mass or less, the resulting polyimide film has good transparency (particularly low haze), which is preferable from the viewpoints of realizing high total light transmittance and a high glass transition temperature.

[0051] As described above, the silicon-containing compound used as a monomer for the polyimide precursor and the polyimide may be synthesized using the common general technical knowledge at the time of filing, or a commercially available product may be used. Commercially available products include methylphenyl silicone oil modified at both ends with amines (Shin-Etsu Chemical Co., Ltd.: X22-1660B-3 (functional group equivalent weight 2200), X22-9409 (functional group equivalent weight 670)), methylphenyl silicone oil modified at both ends with acid anhydride (Shin-Etsu Chemical Co., Ltd.: X22-168-P5-B (functional group equivalent weight 2100)), methylphenyl silicone oil modified at both ends with epoxy (Shin-Etsu Chemical Co., Ltd.: X22-2000 (functional group equivalent weight 620)), dimethyl silicone oil modified at both ends with aminos (Shin-Etsu Chemical Co., Ltd.: PAM-E (functional group equivalent weight 130), X22-161A (functional group equivalent weight 800), X22-161B (functional group equivalent weight 1500), KF8012 (functional group equivalent weight 2200), and BY16-853U (functional group equivalent weight 450) manufactured by Toray Dow Corning Co., Ltd., and JNC Examples of suitable silicone oils include Silaplane FM3311 (number average molecular weight 1000), epoxy-modified dimethyl silicone at both ends (X-22-163A (functional group equivalent 1750) manufactured by Shin-Etsu Chemical Co., Ltd.), alicyclic epoxy-modified dimethyl silicone at both ends (X-22-169B (functional group equivalent 1700) manufactured by Shin-Etsu Chemical Co., Ltd.), hydroxyl-modified dimethyl silicone at both ends (KF-6000 manufactured by Shin-Etsu Chemical Co., Ltd.), mercapto-modified dimethyl silicone at both ends (X-22-167B (functional group equivalent 1700) manufactured by Shin-Etsu Chemical Co., Ltd.), and acid anhydride-modified dimethyl silicone at both ends (X-22-168A (functional group equivalent 1000) manufactured by Shin-Etsu Chemical Co., Ltd.). Among these, amine-modified dimethyl silicone oil at both ends is preferred from the viewpoints of price, improved chemical resistance, and improved Tg.

[0052] Weight average molecular weight In this embodiment, the weight-average molecular weights of the polyimide precursor and polyimide are preferably 50,000 or more, more preferably 60,000 or more, from the viewpoint of reducing the YI value of the polyimide film. From the viewpoint of reducing the haze of the polyimide film, the weight-average molecular weights of the polyimide precursor and polyimide are preferably 150,000 or less, more preferably 120,000 or less. The desirable weight-average molecular weights of the polyimide precursor and polyimide may vary depending on the desired application, the type of polyimide precursor and polyimide, the content of non-solvent components in the resin composition, the type of solvent that the resin composition may contain, and the like.

[0053] <Cyclic siloxane> The resin composition of the present embodiment may contain a cyclic siloxane represented by the following general formula (5), and the silicon-containing compound (monomer used in the polycondensation reaction of the polyimide precursor) used in the resin composition of the present embodiment may contain a silicon-containing compound represented by general formula (3) and a silicon-containing compound represented by general formula (4). [ka] {In the formula, P6 and P7 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or an aromatic group having 6 to 10 carbon atoms, and m is an integer of 2 or greater.}

[0054] The resin composition of the present embodiment contains a compound represented by cyclic siloxane represented by the following general formula (3) in a specific ratio, among the compounds represented by general formula (5). [ka] {wherein n is an integer of 2 or more.}

[0055] The total amount of compounds of general formula (3) where n is 4 is preferably more than 0 ppm and less than 120 ppm, more preferably more than 0 ppm and less than 70 ppm, even more preferably more than 0 ppm and less than 50 ppm, still more preferably more than 0 ppm and less than 40 ppm, and particularly preferably more than 0 ppm and less than 30 ppm, based on the mass of the resin composition. Alternatively, or in addition, the total amount of compounds of general formula (3) where n is 5 is preferably more than 0 ppm and less than 50 ppm, more preferably more than 0 ppm and less than 30 ppm, even more preferably more than 0 ppm and less than 20 ppm, and still more preferably more than 0 ppm and less than 15 ppm, based on the mass of the resin composition. The total amount of compounds of general formula (3) where n is 6 is preferably more than 0 ppm and less than 70 ppm, more preferably more than 0 ppm and less than 60 ppm, even more preferably more than 0 ppm and less than 50 ppm, and still more preferably more than 0 ppm and less than 40 ppm, based on the mass of the resin composition. The total amount of the compounds of general formula (3) in which n is 7 is, based on the mass of the resin composition, preferably more than 0 ppm and not more than 80 ppm, more preferably more than 0 ppm and not more than 70 ppm, even more preferably more than 0 ppm and not more than 60 ppm, and still more preferably more than 0 ppm and not more than 50 ppm. When the total amount of the compounds of general formula (3) is within the above range, the polyimide resin film obtained from the resin composition has fewer defects and the YI value is further reduced, which is preferable.

[0056] When based on the mass of the non-solvent components in the resin composition, the total amount of compounds of general formula (3) where n is 4 is preferably more than 0 ppm and not more than 500 ppm, more preferably more than 0 ppm and not more than 400 ppm, even more preferably more than 0 ppm and not more than 300 ppm, and still more preferably more than 0 ppm and not more than 10 ppm. When based on the mass of the non-solvent components in the resin composition, the total amount of compounds of general formula (3) where n is 5 is preferably more than 0 ppm and not more than 200 ppm, more preferably more than 0 ppm and not more than 100 ppm, even more preferably more than 0 ppm and not more than 50 ppm, and still more preferably more than 0 ppm and not more than 5 ppm. When based on the mass of the non-solvent components in the resin composition, the total amount of compounds of general formula (3) in which n is 6 is preferably more than 0 ppm and not more than 450 ppm, more preferably more than 0 ppm and not more than 300 ppm, even more preferably more than 0 ppm and not more than 250 ppm, and even more preferably more than 0 ppm and not more than 230 ppm. When based on the mass of the non-solvent components in the resin composition, the total amount of compounds of general formula (3) in which n is 7 is preferably more than 0 ppm and not more than 500 ppm, more preferably more than 0 ppm and not more than 400 ppm, even more preferably more than 0 ppm and not more than 300 ppm, and even more preferably more than 0 ppm and not more than 250 ppm. When the total amount of compounds represented by general formula (3) is within the above range, the polyimide resin film obtained from the resin composition has fewer defects, the in-plane uniformity of Rth is improved, and the YI value is further reduced, which is preferable.

[0057] When based on the total mass of the silicon-containing compounds represented by the general formulas (3) and (4), the total amount of the compounds in which n is 4 in the general formula (3) is preferably more than 0 ppm and not more than 1300 ppm, more preferably more than 0 ppm and not more than 800 ppm, even more preferably more than 0 ppm and not more than 500 ppm, and even more preferably more than 0 ppm and not more than 30 ppm.When based on the total mass of the silicon-containing compounds represented by the general formulas (3) and (4), the total amount of the compounds in which n is 5 in the general formula (3) is preferably more than 0 ppm and not more than 500 ppm, more preferably more than 0 ppm and not more than 300 ppm, even more preferably more than 0 ppm and not more than 100 ppm, and even more preferably more than 0 ppm and not more than 15 ppm. Based on the total mass of the silicon-containing compounds represented by the general formulas (3) and (4), the total amount of the compounds in which n is 6 in the general formula (3) is preferably more than 0 ppm and less than 2000 ppm, more preferably more than 0 ppm and less than 1000 ppm, even more preferably more than 0 ppm and less than 500 ppm, and even more preferably more than 0 ppm and less than 20 ppm. Based on the total mass of the silicon-containing compounds represented by the general formulas (3) and (4), the total amount of the compounds in which n is 7 in the general formula (3) is preferably more than 0 ppm and less than 2200 ppm, more preferably more than 0 ppm and less than 1100 ppm, even more preferably more than 0 ppm and less than 600 ppm, and even more preferably more than 0 ppm and less than 10 ppm. When the total amount of the compounds represented by the general formula (3) is within the above range, the polyimide resin film obtained from the resin composition has fewer defects, the in-plane uniformity of Rth is improved, and the YI value is further reduced, which is preferable.

[0058] When based on the mass of the resin composition, the total amount of compounds of general formula (3) in which n is 3 or more and 8 or less is preferably more than 0 ppm and 150 ppm or less, more preferably more than 0 ppm and 130 ppm or less, and even more preferably more than 0 ppm and 100 ppm or less. When based on the mass of the non-solvent components in the resin composition, the total amount of compounds of general formula (3) in which n is 3 or more and 8 or less is preferably more than 0 ppm and 900 ppm or less, more preferably more than 0 ppm and 800 ppm or less, and even more preferably more than 0 ppm and 700 ppm or less. When based on the total mass of the silicon-containing compounds represented by the general formulas (3) and (4), the total amount of compounds of general formula (3) in which n is 3 or more and 8 or less is preferably more than 0 ppm and 4500 ppm or less, more preferably more than 0 ppm and 4000 ppm or less, and even more preferably more than 0 ppm and 3000 ppm or less. When the total amount of the compounds represented by general formula (3) is within the above range, the polyimide resin film obtained from the resin composition has fewer defects, the in-plane uniformity of Rth is improved, and the YI value is further reduced, which is preferable.

[0059] In the past, efforts have been made to reduce the amount of cyclic siloxanes of general formula (3), particularly those in which n is 4 or less, in order to reduce outgassing from the resulting polyimide resin film (see, for example, Patent Documents 3 to 5). However, it was discovered that the prior art methods for reducing cyclic siloxanes in general formula (3) insufficiently reduced the amount of cyclic siloxanes in general formula (3) in which n is 7 or less. Furthermore, it was discovered that a specific amount of compounds of general formula (3) in which n is 5 to 7 can further improve the in-plane uniformity of Rth of the resulting polyimide resin film. While the detailed mechanism behind these effects is unclear, the inventors speculate that it may be as follows. A method for producing a polyimide resin film typically includes a step of applying a composition containing a polyimide precursor composition / polyimide resin to a support such as a glass substrate and heating the composition in an oven, for example, at 100°C under reduced pressure for 30 minutes to remove the solvent (solvent removal step), and a step of heating the composition at a higher temperature, for example, at 400°C for 1 hour to perform imidization (or solvent removal) to form a polyimide resin film. When n is 3 or more and 8 or less, the compound of general formula (3) (methyl side-chain cyclic siloxane) has a boiling point below 400°C at normal pressure, and is therefore volatilized and removed during the imidization process (e.g., heating at 400°C for 1 hour). On the other hand, the solvent removal process is performed at a lower temperature than the imidization process, and it is believed that when n is 3 or more and 8 or less, the compound of general formula (3) is volatilized and removed during this process. However, when the amount of the compound of general formula (3), particularly the compound of n 3 or more and 8 or less, is large, traces of volatilization remain, which is thought to lead to a deterioration in the Rth of the polyimide resin film. Furthermore, in the case of distillation at 250°C or more, the high temperature causes the silicon-containing compound that decomposes during cooling to re-cyclize, which is thought to increase the amount of compounds of general formula (3) with n = 4 and 5. This is thought to result in an increase in defects on the polyimide resin film. To address these problems, the inventors have discovered that the in-plane uniformity of Rth of a polyimide resin film can be improved by purifying compounds containing general formulas (3) and (4) under specific conditions (vacuum distillation), and in particular by adjusting the amount of compounds in which n in general formula (3) is 4 and 5 to a specific amount, or by adjusting the total amount of compounds in general formula (3) in which n is 3 or more and 8 or less to a specific amount.

[0060] In addition to the purification treatment (vacuum distillation) under the specific conditions described above, a method for adjusting the amount of the compound in which n is 4 or 5 in general formula (3) to a specific amount, or for adjusting the total amount of the compound in which n is 3 or more and 8 or less in general formula (3) to a specific amount, can also utilize a process for partially imidizing the polyimide precursor in the synthesis of the resin composition of the present disclosure. A specific example of a partial imidization process is a process for heating a solution containing the polyimide precursor to 160°C or higher (thermal imidization) in the synthesis of the resin of the present disclosure. This process can also be used to adjust the amount of the compound in which n is 4 or 5 in general formula (3) to a specific amount.

[0061] Among the compounds of general formula (3) where n is 3 to 8, it is also preferable to reduce the amount of compounds where n is 3 to 7 and the amount of compounds where n is 3 and 4. That is, based on the mass of the non-solvent components of the resin composition, when the total amount of compounds of general formula (3) where n is 3 is d3 (ppm), the total amount of compounds where n is 4 is d4 (ppm), the total amount of compounds where n is 5 is d5 (ppm), the total amount of compounds where n is 6 is d6 (ppm), and the total amount of compounds where n is 7 is d7 (ppm), d3 + d4 + d5 + d6 + d7 is preferably more than 0 ppm and less than 2000 ppm. Furthermore, it is preferable that d3 + d4 is more than 0 ppm and less than 10 ppm. It is preferable that the amount of compounds of general formula (3) where n is 3 to 7 is more than 0 ppm and less than 2000 ppm from the viewpoint of defect evaluation of the resulting polyimide film. Furthermore, when the amount of the compound of general formula (3) where n is 3 or 4 is more than 0 ppm and not more than 10 ppm, it is preferable from the viewpoint of the in-plane uniformity of Rth of the polyimide films obtained from the polyimide precursor using a purified silicon-containing compound and the polyimide precursor using an unpurified silicon-containing compound.

[0062] <solvent> The resin composition typically contains a solvent. The solvent preferably has good solubility for the polyimide precursor and polyimide and can appropriately control the solution viscosity of the resin composition. The reaction solvent for the polyimide precursor can be used as the solvent for the composition. Among these, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and the compound represented by the general formula (4) are preferred. Specific examples of the solvent composition include N-methyl-2-pyrrolidone (NMP) alone or a mixed solvent of N-methyl-2-pyrrolidone (NMP) and γ-butyrolactone (GBL). The mass ratio of NMP to GBL may be, for example, NMP:GBL (mass ratio) = 10:90 to 90:10.

[0063] Additional Ingredients The resin composition of the present embodiment may further contain additional components in addition to the polyimide precursor, polyimide, cyclic siloxane, and solvent. Examples of the additional components include a surfactant and an alkoxysilane compound.

[0064] surfactants By adding a surfactant to the resin composition of this embodiment, the coatability of the resin composition can be improved, specifically, the occurrence of streaks in the coated film can be prevented. Examples of such surfactants include silicone surfactants, fluorine surfactants, and other nonionic surfactants. Examples of silicone surfactants include organosiloxane polymers KF-640, 642, 643, KP341, X-70-092, and X-70-093 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.); SH-28PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57, and DC-190 (trade names, manufactured by Toray Dow Corning Silicones Co., Ltd.); and SILWET Examples include L-77, L-7001, FZ-2105, FZ-2120, FZ-2154, FZ-2164, FZ-2166, and L-7604 (trade names, manufactured by Nippon Unicar Co., Ltd.); DBE-814, DBE-224, DBE-621, CMS-626, CMS-222, KF-352A, KF-354L, KF-355A, KF-6020, DBE-821, DBE-712 (Gelest), BYK-307, BYK-310, BYK-378, and BYK-333 (trade names, manufactured by BYK Japan); and Granol (trade name, manufactured by Kyoeisha Chemical Co., Ltd.). Examples of fluorine-based surfactants include Megafac F171, F173, and R-08 (trade names, manufactured by Dainippon Ink and Chemicals, Inc.), and Fluorad FC4430 and FC4432 (trade names, manufactured by Sumitomo 3M Limited). Examples of nonionic surfactants other than these include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene octylphenol ether.

[0065] Among these surfactants, silicone surfactants and fluorine surfactants are preferred from the viewpoint of the coatability of the resin composition (suppression of coating streaks), and silicone surfactants are preferred from the viewpoint of reducing the influence of oxygen concentration during the curing step on the YI value and total light transmittance. When a surfactant is used, the amount thereof is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, per 100 parts by mass of the polyimide precursor in the resin composition.

[0066] Alkoxysilane Compounds When a polyimide film obtained from the resin composition of this embodiment is used for a flexible substrate or the like, the resin composition may contain 0.01 to 20 parts by mass of an alkoxysilane compound per 100 parts by mass of polyimide precursor to ensure good adhesion between the support and the polyimide film during the manufacturing process. By ensuring that the content of the alkoxysilane compound is 0.01 part by mass or more per 100 parts by mass of polyimide precursor, good adhesion between the support and the polyimide film can be achieved. Furthermore, from the viewpoint of the storage stability of the resin composition, it is preferable that the content of the alkoxysilane compound is 20 parts by mass or less. The content of the alkoxysilane compound is preferably 0.02 to 15 parts by mass, more preferably 0.05 to 10 parts by mass, and even more preferably 0.1 to 8 parts by mass per 100 parts by mass of polyimide precursor. In addition to improving the adhesion described above, the use of an alkoxysilane compound improves the coatability of the resin composition (suppressing streaks) and reduces the effect of oxygen concentration during curing on the YI value of the polyimide film.

[0067] Examples of alkoxysilane compounds include 3-ureidopropyltriethoxysilane, bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane, γ-aminoethyltriethoxysilane, γ-aminoethyltrippropoxysilane, γ-aminoethyltributoxysilane, γ-aminobutyltriethoxysilane, γ-aminobutyltrimethoxysilane, γ-aminobutyltrippropoxysilane, γ-aminobutyltributoxysilane, phenylsilanetriol, trimethoxyphenylsilane, trimethoxy(p-tolyl)silane, diphenylsilanediol, dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol, and alkoxysilane compounds represented by the following structures. The alkoxysilane compounds may be used alone or in combination of two or more.

[0068] [ka]

[0069] <<Method for 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.

[0070] <Purification of silicon-containing compounds> The polyimide precursor contained in the resin composition of this embodiment can be produced by polycondensation of polycondensation components including an acid dianhydride, a diamine, and a silicon-containing compound. For example, a method for reducing the total amount of the compound of general formula (3) contained in the resin composition of this embodiment can be achieved by purifying the silicon-containing compound before the polycondensation reaction to reduce the total amount of the compound of general formula (3). Alternatively, the resin composition can be purified after the polycondensation reaction to reduce the total amount of the compound of general formula (3).

[0071] An example of a method for purifying a silicon-containing compound is stripping the silicon-containing compound in a vessel while blowing an inert gas, such as nitrogen gas, into the compound. The stripping temperature is preferably 150°C to 300°C, more preferably 200°C to 300°C, and even more preferably 230°C to 300°C. The lower the stripping vapor pressure, the better, and it is preferably 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 4 hours to 12 hours, more preferably 6 hours to 10 hours. By adjusting the conditions as described above, the compound of general formula (3) can be efficiently removed, and the total amount of general formulas (3) and (4) can be controlled within a preferred range.

[0072] <Synthesis of Polyimide Precursor and Polyimide> A partially imidized polyimide precursor can be synthesized by polycondensing a raw material composition containing a silicon-containing compound represented by general formula (4) and a compound represented by general formula (3) with a tetracarboxylic dianhydride and a diamine to obtain a polyimide, followed by further polycondensation with the tetracarboxylic dianhydride and a diamine. Alternatively, a partially imidized polyimide can be synthesized by polycondensing a raw material composition containing a silicon-containing compound represented by general formula (4) and a compound represented by general formula (3) with a tetracarboxylic dianhydride and a diamine to obtain a polyimide precursor, followed by partial imidization of the polyimide precursor. It is preferable to use the silicon-containing compound purified as described above. In a preferred embodiment, the polycondensation component comprises an acid dianhydride, a diamine, and a silicon-containing compound. The polycondensation reaction is preferably carried out in a suitable solvent. Specifically, for example, a method can be used in which a predetermined amount of a diamine component and a silicon-containing compound are dissolved in a solvent, and then a predetermined amount of an acid dianhydride is added to the resulting diamine solution and stirred.

[0073] The molar ratio of acid dianhydride to 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), more preferably 100:95 to 100:105 (0.95 to 1.05 molar parts of diamine per 1 molar part of acid dianhydride), from the viewpoints of increasing the molecular weight of the resulting polyimide precursor and polyimide resin and of the slit coating properties of the resin composition.

[0074] The molecular weights of the polyimide precursor and polyimide 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, adjusting the 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 and polyimide can be.

[0075] It is recommended to use high-purity products as the acid dianhydride component and diamine component. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more, respectively. High purity can also be achieved by reducing the water content in the acid dianhydride component and diamine component. When multiple types of acid dianhydride components and / or multiple types of diamine components are used, it is preferable that the acid dianhydride component as a whole and the diamine component 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.

[0076] The reaction solvent is not particularly limited as long as it can dissolve the acid dianhydride component, the diamine component, and the resulting polyimide precursor and polyimide, and can produce a high-molecular-weight polymer. Examples of such solvents include aprotic solvents, phenolic solvents, ether and glycol solvents. Examples of aprotic solvents include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, N,N-dimethylisobutyramide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and amide solvents represented by the following general formula (7): [ka] {where, R 12 = Equamide M100 (trade name: manufactured by Idemitsu Kosan Co., Ltd.), which is represented by a methyl group, and R 12Examples of suitable solvents include Equamide B100 (trade name: Idemitsu Kosan Co., Ltd.), which is represented by an n-butyl group; 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; and ester solvents such as 2-methoxy-1-methylethyl acetate, 3-methoxy-3-methyl-1-butyl acetate, and diethylene glycol monobutyl ether acetate. Examples of suitable phenol solvents 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, 1,4-dioxane, dipropylene glycol methyl ether acetate, dipropylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc. These solvents may be used alone or in combination of two or more.

[0077] The boiling point at normal pressure of the solvent used in synthesizing the polyimide precursor and polyimide is preferably 60 to 300°C, more preferably 140 to 280°C, and even more preferably 170 to 270°C. A solvent with a boiling point below 300°C shortens the drying process. A solvent with a boiling point of 60°C or higher is less likely to cause roughness on the surface of the resin film or to introduce air bubbles into the resin film during the drying process, resulting in a more uniform film. In particular, from the viewpoints of solubility and reducing edge abnormalities during coating, it is preferable to use a solvent with a boiling point of 170 to 270°C and / or a vapor pressure at 20°C of 250 Pa or less. More specifically, one or more solvents selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and compounds represented by general formula (7) are preferred.

[0078] The water content in the solvent is preferably, for example, 3,000 ppm by mass or less to ensure smooth progress of the polycondensation reaction. In the resin composition of this embodiment, the content of molecules with a molecular weight of less than 1,000 is preferably less than 5% by mass. The presence of molecules with a molecular weight of less than 1,000 in the resin composition is thought to be due to the water content of the solvent and raw materials (acid dianhydride, diamine) used during synthesis. That is, it is thought that the acid anhydride groups of some acid dianhydride monomers are hydrolyzed by water to carboxyl groups, remaining in a low-molecular-weight state without becoming high-molecular-weight. Therefore, the lower the water content of the solvent used in the polycondensation reaction, the better. The water content of the solvent is preferably 3,000 ppm by mass or less, more preferably 1,000 ppm by mass or less. Similarly, the water content of the raw materials is preferably 3,000 ppm by mass or less, more preferably 1,000 ppm by mass or less.

[0079] The moisture content of the solvent is thought to be affected by factors such as the grade of solvent used (dehydrating grade, general-purpose grade, etc.), the solvent container (bottle, 18L can, canister, etc.), the solvent storage conditions (whether or not a noble gas is sealed inside), and the time between opening and use (whether it is used immediately after opening or after aging after opening, etc.). It is also thought to be affected by factors such as the replacement of the reactor with noble gas before synthesis and whether or not noble gas is circulated during synthesis. Therefore, when synthesizing polyimide precursors, it is recommended to use high-purity raw materials and solvents with low moisture content, as well as take measures to prevent moisture from the environment from entering the system before and during the reaction.

[0080] When dissolving each polycondensation component in the solvent, heating may be performed as necessary. From the viewpoint of obtaining a polyimide precursor with a high degree of polymerization, the reaction temperature during synthesis of the polyimide precursor may preferably be 0°C to 120°C, 40°C to 100°C, or 60°C to 100°C, and the polymerization time may preferably be 1 hour to 100 hours, or 2 hours to 10 hours. By setting the polymerization time to 1 hour or more, a polyimide precursor with a uniform degree of polymerization can be obtained, and by setting it to 100 hours or less, a polyimide precursor with a high degree of polymerization can be obtained.

[0081] The resin composition of this embodiment may contain other additional polyimide precursors in addition to the polyimide precursor of this embodiment. However, from the viewpoint of reducing the oxygen dependency of the YI value and total light transmittance of the polyimide film, the mass proportion of the additional polyimide precursor is preferably 30 mass% or less, more preferably 10 mass% or less, based on the total amount of polyimide precursors in the resin composition.

[0082] The polyimide precursor in this embodiment may be partially imidized (partial imidization). Partial imidization of the polyimide precursor can improve the viscosity stability of the resin composition during storage. 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 even more 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 achieved by heating the polyimide precursor to dehydration and ring closure. This heating can be carried out at a temperature of preferably 120°C to 200°C, more preferably 150°C to 180°C, for preferably 15 minutes to 20 hours, more preferably 30 minutes to 10 hours.

[0083] The polyamic acid obtained by the above reaction may be heated with N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal to esterify the carboxylic acid partially or completely, and the resulting product may be used as the polyimide precursor of this embodiment. Esterification can improve viscosity stability during storage. These ester-modified polyamic acids can also be obtained by sequentially reacting the above-mentioned acid dianhydride component with one equivalent of a monohydric alcohol relative to the acid anhydride groups, and a dehydration condensing agent such as thionyl chloride or dicyclohexylcarbodiimide, followed by a condensation reaction with a diamine component.

[0084] <Synthesis of Polyimide> In a more preferred embodiment, the polyimide varnish can be produced as a polyimide solution (also called polyimide varnish) containing polyimide and solvent by dissolving the acid dianhydride component and the diamine component in a solvent, such as an organic solvent, adding an azeotropic solvent such as toluene, and removing the water generated during imidization from the system. The reaction conditions are not particularly limited, but for example, the reaction temperature is 0°C to 180°C and the reaction time is 3 to 72 hours. To fully promote the reaction with the sulfonic acid group-containing diamine, the reaction is preferably heated at 180°C for about 12 hours. Furthermore, the reaction is preferably carried out in an inert atmosphere such as argon or nitrogen.

[0085] <Preparation of Resin Composition> When the solvent used in synthesizing the polyimide precursor or polyimide is the same as the solvent contained in the resin composition, the synthesized polyimide precursor solution or polyimide solution can be used as is as the resin composition of this embodiment. If necessary, the resin composition may be prepared by adding an additional solvent and one or more additional components to the polyimide precursor or polyimide solution at a temperature range of room temperature (25°C) to 80°C and stirring and mixing. This stirring and mixing can be performed using an appropriate device such as a Three-One Motor (manufactured by Shinto Chemical Co., Ltd.) equipped with stirring blades or a planetary centrifugal mixer. If necessary, the resin composition may be heated to 40°C to 100°C.

[0086] On the other hand, when the solvent used in synthesizing the polyimide precursor or polyimide is different from the solvent contained in the resin composition, the polyimide precursor or polyimide may be isolated by removing the solvent in the synthesized polyimide precursor solution or polyimide solution by an appropriate method such as reprecipitation, solvent distillation, etc. Next, a desired solvent and, if necessary, additional components may be added to the isolated polyimide precursor or polyimide at a temperature range of room temperature (25°C) to 80°C, and the mixture may be stirred and mixed to prepare a resin composition.

[0087] In the case of a resin composition containing a polyimide precursor, after preparing the resin composition as described above, the resin composition may be heated, for example, at 130°C to 200°C for 5 minutes to 2 hours to dehydrate and imidize a portion 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. Partial imidization of the polyimide precursor can improve the viscosity stability of the resin composition during storage.

[0088] From the viewpoint of slit coating performance, the solution viscosity of the resin composition is preferably 500 to 100,000 mPa·s, more preferably 1,000 to 50,000 mPa·s, and even more preferably 3,000 to 20,000 mPa·s. Specifically, from the viewpoint of preventing 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. From the viewpoint of preventing 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.

[0089] The solution viscosity of the resin composition during synthesis of the polyimide precursor or polyimide is preferably 200,000 mPa·s or less to facilitate stirring during synthesis. 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 and stirring after the reaction is complete. The solution viscosity of the resin composition in this embodiment is a value measured at 23°C using an E-type viscometer (e.g., VISCONICEHD, manufactured by Toki Sangyo Co., Ltd.).

[0090] From the viewpoint of viscosity stability during storage of the resin composition, the water content of the resin composition of the present 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.

[0091] <Polyimide film and its manufacturing method> The following describes a method for producing a polyimide film according to this embodiment. The first method includes a coating step of coating (casting) a solution of a polyimide precursor onto a support, and a film-forming step of heating the coated solution to dry and imidize it to form a polyimide resin film (referred to as "Production Method 1"). Production Method 1 may optionally include a peeling step of peeling the polyimide resin film from the support to obtain a polyimide film. The second method includes a coating step of coating (casting) a polyimide solution (polyimide varnish) onto a support, and a film-forming step of heating the coated solution to dry it to form a polyimide resin film (referred to as "Production Method 2-1"). Production Method 1 may optionally include a peeling step of peeling the polyimide resin film from the support to obtain a polyimide film. Furthermore, since the second method forms a film from a pre-imidized polyimide solution, it is also possible to produce a polyimide film by pre-drying, peeling it from the support, and further drying it (referred to as "Production Method 2-2").

[0092] <Coating process> In the coating step, the resin composition of the present embodiment is coated onto the surface of a support. The support is not particularly limited as long as it has heat resistance to the heating temperature in the subsequent film-forming step (heating step) and 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, polyphenylene sulfone, and polyphenylene sulfide; and metal substrates such as stainless steel, alumina, copper, and nickel.

[0093] When forming a thin-film polyimide molded product, for example, a glass substrate or a silicon wafer is preferred, and when forming a thick-film or sheet-like polyimide molded product, for example, a support made of PET (polyethylene terephthalate), OPP (oriented polypropylene), etc. is preferred.

[0094] Examples of coating methods include those using a doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, or bar coater; spin coating, spray coating, or dip coating; and printing techniques such as screen printing and gravure printing. The resin composition of this embodiment is preferably coated by slit coating. The coating thickness should be adjusted appropriately depending on the desired resin film thickness and the content of the polyimide precursor in the resin composition, but is preferably about 1 μm to 1,000 μm. The temperature during the coating process may be room temperature, or the resin composition may be heated to, for example, 40°C to 80°C to reduce viscosity and improve workability.

[0095] <Optional drying process> A drying step may be carried out following the coating step, or the drying step may be omitted and the process may proceed directly to the next film-forming step (heating step). The drying step is carried out for the purpose of removing the organic solvent from the resin composition. When carrying out the drying step, an appropriate device such as a hot plate, a box-type dryer, or a conveyor-type dryer may be used. The temperature in the drying step is preferably 80°C to 200°C, more preferably 100°C to 150°C. The time required for the drying step is preferably 1 minute to 10 hours, more preferably 3 minutes to 1 hour. As described above, a coating film containing a polyimide precursor is formed on a support.

[0096] <Film formation process> Subsequently, a film formation step (heating step) is carried out. In the case of a polyimide precursor solution, the heating step is a step of removing the organic solvent contained in the coating film and promoting the imidization reaction of the polyimide precursor in the coating film to obtain a polyimide resin film. In the case of a polyimide solution, the heating step is a step of removing the organic solvent contained in the coating film to obtain a polyimide resin film. This heating step can be carried out 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 carried out simultaneously with the drying step, or both steps can be carried out sequentially.

[0097] The heating step may be performed in an air atmosphere, but is preferably performed in an inert gas atmosphere from the viewpoints of safety and obtaining good transparency, a low thickness direction Rth, and a low YI value for the resulting polyimide film. Examples of inert gases include nitrogen and argon. In the case of a polyimide precursor solution, 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. A temperature of 250°C or higher allows for good imidization, while a temperature of 550°C or lower can avoid problems such as a decrease in the transparency and deterioration of heat resistance of the resulting polyimide film. In the case of a polyimide solution, the heating temperature may be appropriately set depending on the type of polyimide and the type of solvent in the resin composition, but is preferably 50°C to 450°C. The heating time is preferably about 6 minutes to 10 hours.

[0098] In this embodiment, in the case of a polyimide precursor solution, the oxygen concentration of the ambient atmosphere during 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 reduced to 30 or less.

[0099] Peeling process In the peeling step, the polyimide resin film on the support may be peeled off after being cooled to, for example, room temperature (25° C.) to about 50° C. Examples of this peeling step include the following modes (1) to (4).

[0100] (1) A method in which a structure containing a polyimide resin film / support is prepared by the above method, and then a laser is irradiated 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 laser types include solid-state (YAG) lasers and gas (UV excimer) lasers. It is preferable to use a spectrum with a wavelength of 308 nm or the like (see, for example, JP-A Nos. 2007-512568 and 2012-511173). (2) 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, the release layer, and the 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, and alkyd-based release agents may also be used (see, for example, JP 2010-067957 A and JP 2013-179306 A). This method (2) and the laser irradiation method (1) may be used in combination.

[0101] (3) A method of obtaining a polyimide resin film by using an etchable metal substrate as a support, obtaining a structure including a polyimide resin film / support, and then etching the metal with an etchant. Examples of metals that can be used include copper (specifically, electrolytic copper foil "DFF" manufactured by Mitsui Mining & Smelting Co., Ltd.) and aluminum. Examples of etchants that can be used include ferric chloride for copper and dilute hydrochloric acid for aluminum. (4) A method in which, after obtaining a structure containing a polyimide resin film / support by the above method, an adhesive film is attached to the surface of the polyimide resin film, the adhesive film / polyimide resin film is separated from the support, and then the polyimide resin film is separated from the adhesive film.

[0102] Among these peeling methods, method (1) or (2) is preferred from the viewpoint of the refractive index difference between the front and back surfaces of the resulting polyimide resin film, the YI value, and the elongation. From the viewpoint of the refractive index difference between the front and back surfaces of the resulting polyimide resin film, method (1), i.e., performing an irradiation step of irradiating with a laser from the support side prior to the peeling step, is more preferred. In method (3), when copper is used as the support, the resulting polyimide resin film tends to have a large YI value and a small elongation. This is thought to be due to the influence of copper ions.

[0103] The thickness of the resulting polyimide film is not limited, but is preferably 1 to 200 μm, more preferably 5 to 100 μm.

[0104] <Yellowness index (YI value)> 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 varies depending on the monomer skeleton of the polyimide precursor, but when the monomer skeleton is the same, the YI value tends to decrease as the weight-average molecular weight of the polyimide precursor increases.

[0105] The YI value is affected by, for example, the amine value of the silicon-containing compound used; a higher amine value results in a higher YI value, while a lower amine value results in a lower YI value. However, polyimide precursors using purified silicon-containing compounds, i.e., polyimide precursors in which the total amount of compounds represented by general formula (3) is within the above-mentioned range, tend to produce polyimide resin films with lower YI values ​​than polyimide precursors using unpurified silicon-containing compounds with the same amine value. While the mechanism behind this is unclear, the inventors speculate as follows: In conventional purification methods, non-cyclic low-molecular-weight diamines used in the production of polyimide precursors remain, decomposing during polyimide curing to generate radicals, which can increase (deteriorate) the YI value. By reducing the amount of cyclic siloxanes represented by general formula (3), not only the cyclic siloxanes represented by general formula (3) are removed during purification, but also the relatively volatile low-molecular-weight diamines 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 general formula (3) is reduced according to this embodiment will produce a polyimide resin film with a further improved YI value. Since it is difficult to reduce the amount of non-cyclic low-molecular-weight diamines using conventional purification methods, 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.

[0106] <<Uses of Polyimide Film>> Polyimide films obtained by curing the resin composition of this embodiment can be used, for example, as semiconductor insulating films, thin film transistor liquid crystal display (TFT-LCD) insulating films, electrode protective films, and transparent substrates for display devices such as liquid crystal displays, organic electroluminescent displays, field emission displays, and electronic paper. In particular, polyimide films obtained by curing the resin composition of this embodiment can be suitably used in the manufacture of flexible devices, such as flexible substrates, flexible displays, thin film transistor (TFT) substrates, color filter substrates, touch panel substrates, and transparent conductive film (ITO, indium tin oxide) substrates. Flexible devices to which the polyimide film of this embodiment can be applied include, for example, 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.

[0107] 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° C. to 650° C. Specifically, when fabricating a TFT device using amorphous silicon, a process temperature of 250° C. to 350° C. is generally required, and the polyimide film of this embodiment must be able to withstand this temperature, so specifically, it is necessary to appropriately select a polymer structure having a glass transition temperature and thermal decomposition onset temperature equal to or higher than the process temperature.

[0108] 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, and the polyimide film of this embodiment must be able to withstand that temperature. Therefore, it is necessary to appropriately select a polymer structure that has 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.

[0109] When fabricating a TFT device using low-temperature polysilicon (LTPS), a process temperature of 380°C to 520°C is generally required, and the polyimide film of this embodiment must be able to withstand this temperature, so it is necessary to appropriately select a glass transition temperature and a thermal decomposition onset temperature that are equal to or higher than the maximum temperature in the TFT fabrication process. On the other hand, due to the thermal history, the optical properties (particularly the light transmittance, Rth, 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 being subjected to the thermal history.

[0110] Hereinafter, a display and a method for producing a laminate will be described as examples of applications of the polyimide film of this embodiment.

[0111] <Display manufacturing method> The method for producing a display of this embodiment includes a coating step of coating the resin composition of this embodiment on the 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 elements on the polyimide resin film, and a peeling step of peeling the polyimide resin film on which the elements have been formed from the support. The display may be a flexible display.

[0112] Flexible OLED display manufacturing example Fig. 1 is a schematic diagram showing the structure above a polyimide substrate of a top-emission flexible organic EL display as an example of a display of this embodiment. The organic EL structure 25 in Fig. 1 will be described. For example, an organic EL element 250a that emits red light, an organic EL element 250b that emits green light, and an organic EL element 250c that emits blue light are arranged in a matrix as one unit, and the light-emitting region of each organic EL element is defined by a partition wall (bank) 251. 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. On the lower layer 2a, which is a CVD multi-layer film (multi-barrier layer) made of silicon nitride (SiN) and silicon oxide (SiO), are provided a TFT 256 (selected from low-temperature polysilicon (LTPS) and metal oxide semiconductor (IGZO, etc.)) for driving the organic EL elements, an interlayer insulating film 258 with contact holes 257, and a plurality of lower electrodes 259. 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.

[0113] The manufacturing process for a flexible organic EL display includes the steps of preparing a polyimide film on a glass substrate support, preparing the organic EL substrate shown in FIG. 1 on top of the polyimide film, preparing a sealing substrate, assembling the two substrates together, and peeling the organic EL display prepared on the polyimide film from the glass substrate support. Well-known manufacturing processes can be applied to the organic EL substrate manufacturing process, sealing substrate manufacturing process, and assembly process. Examples are given below, but the present invention is not limited to these. The peeling process is the same as the polyimide film peeling process described above.

[0114] For example, referring to Figure 1, first, a polyimide film is prepared on a glass substrate support using the above-mentioned method. Then, a multi-barrier layer (lower substrate 2a in Figure 1) consisting of a multi-layer structure of silicon nitride (SiN) and silicon oxide (SiO) is prepared on top of that using CVD or sputtering. A metal wiring layer for driving the TFT is then prepared on top of that using photoresist or the like. An active buffer layer such as SiO is then prepared on top of that using CVD, and a TFT device (TFT 256 in Figure 1) made of metal oxide semiconductor (IGZO) or low-temperature polysilicon (LTPS) or the like is then prepared on top of that. After the flexible display TFT substrate is prepared, an interlayer insulating film 258 with contact holes 257 is formed using a photosensitive acrylic resin or the like. An ITO film is then formed by sputtering or the like, and a lower electrode 259 is formed to pair with the TFT.

[0115] Next, partition walls (banks) 251 are formed using a photosensitive polyimide or the like, and then hole transport layers 253 and light-emitting layers 254 are formed in each space partitioned by the partition walls. An upper electrode (cathode) 255 is formed to cover the light-emitting layers 254 and the partition walls (banks) 251. Then, using a fine metal mask or the like as a mask, a red-emitting organic EL material (corresponding to the red-emitting organic EL element 250a in FIG. 1), a green-emitting organic EL material (corresponding to the green-emitting organic EL element 250b in FIG. 1), and a blue-emitting organic EL material (corresponding to the blue-emitting organic EL element 250c in FIG. 1) are vapor-deposited by a known method to fabricate 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 from the glass substrate support by a known peeling method, such as laser peeling, to fabricate a top-emission flexible organic EL display. When the polyimide of this embodiment is used, a see-through flexible organic EL display can be produced. A bottom-emission flexible organic EL display may also be produced by a known method.

[0116] Flexible LCD display manufacturing example Flexible liquid crystal displays can be fabricated using the polyimide film of this embodiment. Specifically, a polyimide film is fabricated on a glass substrate support using the method described above, and a TFT substrate made of, for example, amorphous silicon, a metal oxide semiconductor (e.g., IGZO), and low-temperature polysilicon is fabricated using the method described above. Separately, a polyimide film is fabricated on the glass substrate support using the coating and film-forming steps of this embodiment, and a color filter glass substrate (CF substrate) equipped with the polyimide film is fabricated using a color resist or the like according to a known method. A sealing 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, excluding the liquid crystal injection port. Spherical spacers made of plastic or silica and having a diameter corresponding to the thickness of the liquid crystal layer are dispersed on the other substrate.

[0117] Next, the TFT substrate and the CF substrate are bonded together, and the sealing material is cured. Liquid crystal material is then injected into the space surrounded by the TFT substrate, the CF substrate, and the sealing material using a vacuum method. A thermosetting resin is applied to the liquid crystal injection port, and the liquid crystal material is sealed by heating, forming 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 using a laser peeling method or other method, thereby producing a flexible liquid crystal display.

[0118] <Method for 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 the 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.

[0119] The elements in the laminate may be those exemplified in the production of the flexible device described above. A glass substrate, for example, may be used as the support. The preferred specific procedures for the coating step and film formation step are the same as those described for the polyimide film production method described above. In the element formation step, the elements are formed on a polyimide resin film serving as a flexible substrate formed on a support. Thereafter, the polyimide resin film and the elements may be peeled off from the support in an optional peeling step to obtain a flexible substrate. [Example]

[0120] Hereinafter, the embodiments of the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

[0121] <<Measurement and Evaluation Methods>> <Non-solvent components> The total mass of the monomers used in the polyimide precursor can be used as the mass of the non-solvent components contained in the resin composition. Alternatively, the mass of the non-solvent components 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 then subtracting the mass of the solvent from the mass of the resin composition. The conditions for GC include the following: Apparatus: 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℃

[0122] <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, prepared 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) immediately 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)

[0123] <Functional group equivalent> The functional group equivalent weight was measured according to existing standards as follows. The functional group equivalent weight of the amino group was measured in accordance with JIS K 7237. The functional group equivalent weight of the epoxy group was measured in accordance with JIS K 7236. The functional group equivalent weight of the hydroxy group was measured in accordance with JIS K 0070. For other functional groups, the molecular weight of the silicon-containing compound per mole of the functional group was also determined by titration.

[0124] Analysis of Cyclic Siloxane Concentration The concentration of the cyclic siloxane of general formula (3) contained in the resin composition containing the polyimide precursor and the silicon-containing compound (general formula (3)) was quantitatively analyzed by GC (gas chromatography analysis) as shown below (see Analysis of Cyclic Siloxane Concentration (Based on Silicon-Containing Compound) below).

[0125] Analysis of Cyclic Siloxane Concentration (Composition Standard / Non-Solvent Component Standard) (1) Overview 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 of general formula (3) (hereinafter also referred to as D4 form) according to the method described below. The amount of cyclic siloxane contained in the resin composition was measured by heating the resin composition at 150°C for 30 minutes in a pyrolyzer and analyzing the resulting volatile components by GC / MS. Using the calibration curve prepared in advance, the peak area of ​​each compound obtained was converted into the concentration of D4 form. GC / MS measurements were carried out 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 Labs) All GC / MS measurements were carried out under the following conditions: Column temperature: 40°C for 5 minutes, increased 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)

[0126] (2) Preparation of a calibration curve A sample of the compound of general formula (3) where n = 4 (hereinafter referred to as the D4 isomer) (manufactured by Tokyo Chemical Industry Co., Ltd.) was weighed into a 10 mL volumetric flask and chloroform was used as a solvent to prepare samples with D4 isomer concentrations of 0.1 mg / mL and 0.01 mg / mL. A liquid sampler was attached to a pyrolyzer set at 400 °C, and 1 μL of the adjusted sample was measured using a microsyringe and injected into the pyrolyzer. While the pyrolyzer was heated to 400 °C, the column was immersed in liquid nitrogen to trap volatile components within the column. One minute after heating was completed, the column was removed from the liquid nitrogen and subjected to GC / MS analysis. The slope of the D4 isomer calibration curve was calculated from the D4 isomer concentration and the resulting peak area. The retention times of cyclic siloxanes in GC / MS analysis using the equipment and measurement conditions used are shown in Table 1 below. The same applies to subsequent GC / MS measurements.

[0127] [Table 1]

[0128] Dn (n=3 to 8) in Table 1 above is a cyclic siloxane corresponding to n=3 to 8 in the general formula (3) above.

[0129] (3) Analysis of the concentration of cyclic siloxane of general formula (3) in the resin composition The concentration of the compound of general formula (3) contained in the resin composition was measured by heating the resin composition to 150°C and measuring the resulting volatile components by GC / MS. The concentration of each compound was calculated from the peak area of ​​the measurement results for 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 the peak overlapped with other compounds, the peak area calculated from the mass chromatogram (MS) at m / z = 281 was used.

[0130] A sample cup containing approximately 1 mg of the resin composition was placed in a pyrolyzer furnace (He atmosphere) set at 150°C and heated at 150°C for 30 minutes. The resulting volatile components were measured by GC / MS analysis. Using a previously prepared calibration curve, the peak area of ​​each compound obtained was converted to the D4 concentration. Dn (μg / g) = {Dn (GC-Area)} / {slope of D4 calibration curve} / {mass of weighed resin composition (mg)} × 1000 In the formula, n corresponds to the number of carbon atoms n in general formula (3), and n is an integer of 3 or more.

[0131] Analysis of cyclic siloxane concentration in raw material composition (based on silicon-containing compounds) (overview) The cyclic siloxane concentration was measured by analyzing a solution of a silicon-containing compound (containing the silicon-containing compound of general formula (3)) dissolved in acetone (containing n-tetradecane as an internal standard) by GC. The concentration of each compound was determined from the peak area of ​​each compound obtained, using the peak area of ​​n-tetradecane as the standard, according to the method described below. GC measurements were carried out using the following equipment. GC system: 7890A (Agilent Technologies) Column: J&W Scientific Durabond DB-5MS (MEGABORE, inner diameter 0.53 mm, length 30 m, liquid phase thickness 1.0 μm) All GC measurements were carried out under the following conditions: Column temperature: 50°C, increased at 10°C / min, held at 280°C for 17 min, total 40 min Inlet temperature: 270℃ Carrier gas: He Injection method: Split method (split ratio 1 / 10) Detector: FID (300℃)

[0132] (Calculation of cyclic siloxane content) The amount of the cyclic siloxane of general formula (3) was calculated according to the following formula. Dn (μg / g) = {total amount (μg) of compounds of general formula (3)} / {total mass (g) of compounds of general formulas (3) and (4)} = {Dn (GC-Area)} / {n-tetradecane (GC-Area) × GC-Area Factor} × 20 × 100 In the formula, n corresponds to the number of carbon atoms n in general formula (3), and n is an integer of 3 or more. The GC-Area Factor in the formula was calculated according to the following formula. GC-Area Factor = molecular weight / number of carbon atoms

[0133] The retention times (minutes) of cyclic siloxanes in GC measurements using the equipment and the above measurement conditions are as shown in Table 2 below. The same applies to subsequent GC measurements.

[0134] [Table 2]

[0135] Dn (n=3 to 8) in Table 2 above is a cyclic siloxane corresponding to n in the general formula (3) above.

[0136] (Analysis of cyclic siloxane concentration) The concentration of cyclic siloxanes of general formula (3) contained in silicon-containing compounds was analyzed using the following procedure. 0.1 g of silicon-containing compound was dissolved in 10 mL of acetone (containing 20 μg / mL of n-tetradecane as an internal standard) and allowed to stand for 16 hours. 1 μL of the solution was measured using a microsyringe and introduced into a GC for measurement. In the resulting chromatogram, the peak areas of each cyclic siloxane and n-tetradecane were calculated using the software attached to the GC, and the cyclic siloxane concentration was determined using the formula shown above.

[0137] <Evaluation of storage stability of resin composition> The resin composition is usually stored in a freezer, but after being transported to the customer and before being actually used, it is repeatedly stored in a freezer and at room temperature. The storage stability of the resin composition when kept under such conditions was evaluated as follows. The obtained resin compositions of the Examples and Comparative Examples were stored in a refrigerator at -20°C for at least one day. The samples were then left in an atmosphere of 23°C and 50% humidity for 24 hours. They were then stored again in a refrigerator at -20°C for 24 hours. Subsequently, they were left again in an atmosphere of 23°C and 50% humidity for 24 hours. After that, the cycle of storing in a refrigerator at -20°C for 24 hours and leaving in an atmosphere of 23°C and 50% humidity for 24 hours was repeated three times, and the obtained samples were evaluated according to the following criteria. A: No abnormalities such as turbidity or increased viscosity were observed in the resin composition by visual inspection (good). B: Turbidity is confirmed by visual observation of the resin composition, but no increase in viscosity is observed (acceptable) C: The resin composition becomes cloudy when observed with the naked eye, and an increase in viscosity is observed (unacceptable).

[0138] <Evaluation of paint film repellency> The resin compositions of the Examples and Comparative Examples were applied to an alkali-free glass substrate (hereinafter referred to as "glass substrate" or simply "substrate") measuring 300 mm in length, 350 mm in width, and 0.5 mm in thickness, in an area 5 mm inward from the edge of the glass substrate, so that the cured film would be 10 μm thick. A slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions) was used for application. The solvent was removed from the resulting coated glass substrate using a vacuum dryer (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 80°C and 100 Pa for 30 minutes, yielding a glass substrate with a resin composition coating measuring 290 mm in length, 340 mm in width, and 10 μm in thickness. The edges of the coating (beginning of coating, sides, and end of coating) were observed with a laser microscope, and the length of the repellent area was measured. Five substrates were coated under the same conditions, and the average length of the repellent area was determined and evaluated according to the following criteria. A: The length of the paint film repelling part is less than 10 mm (good) B: The length of the paint film repelling part is 10 mm or more and less than 30 mm (acceptable) C: The length of the paint film's repelling part is 30 mm or more (not permitted)

[0139] <In-plane uniformity of retardation (Rth) of polyimide resin film> The resin compositions of the Examples and Comparative Examples were applied to an alkali-free glass substrate (hereinafter referred to as "glass substrate" or simply "substrate") measuring 300 mm in length, 350 mm in width, and 0.5 mm in thickness, in an area 5 mm inward from the edge of the glass substrate, so that the cured film would be 10 μm thick. A slit coater (LC-R300G, manufactured by SCREEN Finetech Solutions) was used for application. The resulting glass substrate with the coating was then dried in a vacuum dryer (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 80°C, 100 Pa, and for 30 minutes to remove the solvent, yielding a glass substrate with a resin composition coating measuring 290 mm in length, 340 mm in width, and 10 μm in thickness. Ten glass substrates of the same composition were treated in succession. When treating a different composition, the vacuum dryer was pre-baked at 600°C for at least 5 hours before use. The glass substrate with the resulting resin composition coating was heated in an oven (INH-9N1, manufactured by Koyo Thermo Systems Co., Ltd.) at 400°C for 1 hour under a nitrogen atmosphere (oxygen concentration 300 ppm or less) to form a polyimide resin film on the glass substrate. The in-plane uniformity of Rth was evaluated using the prepared polyimide resin film. The thickness direction Rth (10 μm equivalent) was measured at four measurement points (290 mm width) at 80 mm intervals from 25 mm inside the edge of the polyimide resin film, and four measurement points (340 mm width) at 80 mm intervals from 50 mm inside the edge of the polyimide resin film, for a total of 16 measurement points (4 × 4) using a retardation birefringence measurement device (KOBRA-WR, manufactured by Oji Scientific Instruments). From the results, a ±3 sigma range was calculated, and the in-plane Rth uniformity of the PI precursor coating film was evaluated according to the following criteria. A: In-plane uniformity (±3 sigma) is less than 10 (good) B: In-plane uniformity (±3 sigma) is 10 or more and less than 20 (acceptable) C: In-plane uniformity (±3 sigma) is 20 or more (unacceptable)

[0140] <Method for purifying silicon-containing compounds> The silicon-containing compounds described in the Examples and Comparative Examples below were purified by the following method to reduce the cyclic siloxane content. The concentration of cyclic siloxane after purification was analyzed by the above method. <Refined A> 10 kg of a silicon-containing compound was placed in a flask, and stripping was carried out at a temperature of 200° C. and a pressure of 200 Pa for 8 hours while blowing nitrogen gas into the flask. <Purification B> 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 nitrogen gas into the flask. Purified C: Based on the synthesis example of the amino-terminated silicone oil (purified product) described in JP 2016-029126 A Add 1000g of acetone to 100g of silicon-containing compound, and stir at room temperature for 30 minutes.Use centrifuge to separate acetone and silicone oil at 2500rpm for 15 minutes, then remove acetone by decantation.After repeating this operation three times, use evaporator to remove acetone, and obtain purified silicon-containing compound. Purification D: Purification Example 1 described in JP-A-2006-028533 500 g of a silicon-containing compound was placed in a flask, and stripping was carried out at a temperature of 250° C. and a pressure of 1330 Pa for 2 hours while blowing nitrogen gas into the flask. Purification E: Purification Example 2 described in JP-A-2006-028533 100 g of a silicon-containing compound was placed in 300 g of 2-butanone and dissolved uniformly. This solution was slowly poured into methanol with stirring to perform reprecipitation. The above reprecipitation was repeated three times, and then dried to obtain a purified silicon-containing compound. <Refined F> 10 kg of a silicon-containing compound was placed in a flask, and stripping was carried out at a temperature of 150° C. and a pressure of 300 Pa for 2 hours while blowing nitrogen gas into the flask.

[0141] Example 1 NMP (307 g) as the solvent, toluene (31 g), 44DAS (7.1 g) as the diamine, and 9.94 g of the silicon-containing compound (1) (9.94 g) purified through purification process A (general formula (4) where L1 and L2 are amino groups (-NH2), R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are methyl groups, j and k are 0, and the functional group equivalent weight is 1500) were added to a separable flask equipped with a stirrer, a Dean-Stark tube, and a reflux condenser. The mixture was stirred under nitrogen gas. Subsequently, BPAF (22.9 g) was added as the acid dianhydride at room temperature. The internal temperature was then raised to 160 °C and refluxed at 160 °C for 1 hour to carry out imidization. After imidization was completed, the temperature was raised to 180 °C, and the reaction was continued while the toluene was removed. After 12 hours of reaction, the oil bath was removed and the mixture was allowed to cool to room temperature. Next, 44DAS (7.6 g) as a diamine and PMDA (10.9 g) as an acid dianhydride were added with stirring. The mixture was then stirred at room temperature for 48 hours to obtain a partially imidized polyimide precursor (PAI). The resulting varnish was stored in a freezer (set at -20°C, hereinafter the same) and thawed before use for evaluation.

[0142] Examples 2 to 15 The same procedure as in Example 1 was carried out, except that the solvent, acid dianhydride, diamine, type and amount of silicon-containing compound, and purification conditions for the silicon-containing compound were changed to those shown in Tables 3 and 4. The types of silicon-containing compounds in the table are as follows: Silicon-containing compound (2): A compound represented by general formula (4) in which L1 and L2 are acid anhydride groups, R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are methyl groups, j and k are 0, and the functional group equivalent is 800. Silicon-containing compound (3): A compound represented by general formula (4) in which L1 and L2 are amino groups (-NH2), R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are phenyl groups, j and k are 0, and the functional group equivalent is 2200. Silicon-containing compound (4): A compound represented by the general formula (4) in which L1 and L2 are amino groups (-NH2), R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are phenyl groups, j and k are 0, and the functional group equivalent is 670. Silicon-containing compound (5): (In general formula (4), L1 and L2 are amino groups (-NH2), R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are methyl groups, j and k are 0, and the compound has a functional group equivalent of 800.

[0143] Comparative Example 1 A separable flask equipped with a stirrer, a Dean-Stark tube, and a reflux condenser was charged with nitrogen gas. As shown in Tables 1 and 2, NMP (307 g) as the solvent, toluene (31 g), and 44DAS (7.6 g) as the diamine were added with stirring. PMDA (10.9 g) as the acid dianhydride was then added at room temperature. The internal temperature was then raised to 160°C and heated under reflux at 160°C for 1 hour to carry out imidization. After imidization was complete, the temperature was raised to 180°C, and the reaction was continued while the toluene was removed. After 12 hours of reaction, the oil bath was removed and the mixture was returned to room temperature. Next, 44DAS (7.1 g) as a diamine, untreated silicon-containing compound (1) (9.94 g) (general formula (4) in which L1 and L2 are amino groups (-NH2), R1 is a trimethylene group (-CH2CH2CH2-), R2 and R3 are methyl groups, j and k are 0, and the functional group equivalent is 1500) and BPAF (22.9 g) as an acid dianhydride were added with stirring. The mixture was then stirred at room temperature for 48 hours to obtain a partially imidized polyimide precursor (PAI). The resulting varnish was stored in a freezer (set at -20 °C, same below) and thawed before use for evaluation.

[0144] Comparative Example 2 A separable flask equipped with a thermometer and a stirrer was charged with nitrogen gas. As shown in Table 3, 158 g of NMP (as a solvent), 16 g of toluene, 7.1 g of 44DAS (as a diamine), and 9.94 g of purified silicon-containing compound (1) (purified D) were added with stirring. The mixture was stirred at room temperature for 12 hours to obtain a polyamic acid solution. 90 g of NMP and 13.45 g of pyridine (as an imidization catalyst) were added to the polyamic acid solution and completely dispersed. Then, 17.33 g of acetic anhydride was added and stirred at 80°C for 4 hours. After cooling the solution to room temperature, a mixture of 110 g of 2-propyl alcohol (hereinafter referred to as "IPA") and 20 g of NMP was added dropwise at a rate of 2-3 drops per second to precipitate the polyimide. 375 g of IPA was then added, and the mixture was stirred for approximately 30 minutes. The mixture was then subjected to suction filtration using a Kiriyama funnel. The obtained solid was washed with IPA, and after repeating the washing process five times, it was dried for 8 hours in a vacuum oven set at 120°C to dissolve the NMP, obtaining an NMP solution of polyimide (PI) with a solid content of 25%. The obtained varnish was stored in a freezer (set at -20°C, same below) and thawed before use for evaluation.

[0145] Comparative Example 3 The same procedure as in Comparative Example 2 was carried out, except that the solvent, acid dianhydride, diamine, type and amount of silicon-containing compound, and purification conditions for the silicon-containing compound were changed to those shown in Tables 3 and 4.

[0146] Comparative Example 4: Based on Japanese Patent Application Laid-Open No. 9-263636 The same procedure as in Comparative Example 2 was carried out, except that the solvent, acid dianhydride, diamine, type and amount of silicon-containing compound, and purification conditions for the silicon-containing compound were changed to those shown in Tables 3 and 4. (In accordance with JP-A-9-263636, the molar percentage of the silicon-containing compound in the total diamines was set to 1.9 mol%, which is 2 mol% or less.)

[0147] Comparative Example 5 NMP (313 g) as a solvent, 44DAS (11.6 g) as a diamine, and the purified silicon-containing compound (1) (10.56 g) from Treatment C were added to a 3 L separable flask equipped with a stirrer while introducing nitrogen gas, followed by the addition of BPAF (36.7 g) as an acid dianhydride. The mixture was stirred at room temperature for 48 hours to obtain an NMP solution of polyamic acid (PAA) (hereinafter also referred to as varnish). The resulting varnish was stored in a freezer (set at -20°C, hereinafter the same) and thawed before use for evaluation.

[0148] Comparative Example 6 Comparative Example 5 was carried out in the same manner as Comparative Example 5, except that the solvent, acid dianhydride, diamine, type and amount of silicon-containing compound, and purification conditions of the silicon-containing compound were changed to those shown in Tables 3 and 4.

[0149] Comparative Example 7 A thermometer and a stirring rod with a stirring blade were installed in a 300 mL four-neck flask. Next, 109 g of NMP was added under a dry nitrogen gas stream, and the temperature was raised to 60 °C. After the temperature was raised, 14.9 g of CHDA and 2.68 g of silicon-containing compound (4) that had been subjected to purification D treatment were added with stirring, and washed in with 20 g of NMP. After confirming that the CHDA had dissolved, 32.1 g of BPDA and 15.6 g of BSAA were added, and washed in with 20 g of NMP. After 4 hours, the mixture was cooled to obtain an NMP solution of polyimide precursor (PAA).

[0150] Comparative Example 8 20.2 g of 6FODA and 113 g of NMP were added to a 500 mL five-neck round-bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean-Sook equipped with a condenser, a thermometer, and a glass end cap. The solution was stirred at 70 ° C. under a nitrogen atmosphere at 200 rpm to obtain a solution. 19.2 g of CpODA and 20 g of NMP were added all at once to this solution, and then 0.302 g of TEA was added as an imidization catalyst. The mixture was heated with a mantle heater and the reaction temperature was raised to 190 ° C. over approximately 20 minutes. The distilled components were collected, and the reaction temperature was maintained at 190 ° C. and refluxed for 1 hour while adjusting the rotation speed according to the increase in viscosity. 50 g of NMP was then added, and the reaction temperature was cooled to 50 ° C. to obtain a solution containing an oligomer having imide repeating structural units. To the resulting solution, 40 g of s-BPDA and 8 g of NMP were added all at once, and the mixture was stirred at 50°C for 5 hours. Then, 107.143 g of NMP was added, and after homogenization, a mixture of 9.19 g of silicon-containing compound (3) dissolved in 10 g of NMP was added, and the mixture was further stirred for about 1 hour. NMP was then added so that the solids concentration was about 15% by mass, and the mixture was homogenized to obtain an NMP solution of a partially imidized polyimide precursor (PAI).

[0151] The abbreviations used in the examples and comparative examples are as follows. <Acid dianhydride> BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride PMDA: Pyromellitic dianhydride CpODA: norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid dianhydride BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride BSAA: 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride ODPA: 4,4'-oxydiphthalic anhydride <Diamine> 44DAS: 4,4'-bis(diaminodiphenyl) sulfone 33DAS: 3,3'-bis(diaminodiphenyl) sulfone CHDA: 1,4-cyclohexanediamine 6FODA: 2,2'bis(trifluoromethyl)-4,4'diaminodiphenyl ether HFBAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane BAC: 1,3-bis(aminomethyl)cyclohexane

[0152] [Table 3]

[0153] [Table 4] [Explanation of symbols]

[0154] 2a Lower board 2b Sealing substrate 25 Organic EL structure 250a Red light-emitting organic L element 250b Green light-emitting organic EL element 250c Blue light-emitting organic EL element 251 Partition (Bank) 252 Lower electrode (anode) 253 Hole transport layer 254 luminescent layer 255 Upper electrode (cathode) 256 TFT 257 Contact Hole 258 Interlayer insulating film 259 Lower Electrode 261 Hollow part

Claims

1. a partially imidized polyimide precursor containing structural units represented by the following general formulas (1-1) and (1-2) and a structural unit represented by the following general formula (2); A compound represented by the following general formula (3): A resin composition comprising: The total amount of compounds of the following general formula (3) in which n is 4 is more than 0 ppm and 120 ppm or less based on the mass of the resin composition, or the total amount of compounds represented by the following general formula (3) in which n is 4 is more than 0 ppm and 120 ppm or less, based on the mass of the resin composition, and the total amount of compounds represented by the following general formula (3) in which n is 5 is more than 0 ppm and 50 ppm or less, based on the mass of the resin composition; The resin composition, wherein the imidization rate of the polyimide precursor is 5% or more and 80% or less. 【Chemistry 1】 {In the formula, P １ represents a divalent organic group, and P ２ represents a tetravalent organic group, and p represents a positive integer. 【Chemistry 2】 {In the formula, P ８ represents a divalent organic group, and P ９ represents a tetravalent organic group, and q represents a positive integer. 【Transformation 3】 {In the formula, P ３ and P ４ are each independently a monovalent aliphatic hydrocarbon having 1 to 5 carbon atoms, and r is an integer from 1 to 200. 【Chemistry 4】 {wherein n is an integer of 2 or more.}

2. The total amount of the compound of general formula (3) in which n is 4 is more than 0 ppm and 70 ppm or less based on the mass of the resin composition, or The resin composition according to claim 1, wherein the total amount of the compounds of general formula (3) in which n is 5 is more than 0 ppm and 30 ppm or less, based on the mass of the resin composition.

3. The total amount of the compounds of the general formula (3) in which n is 4 is more than 0 ppm and 30 ppm or less based on the mass of the resin composition, or The resin composition according to claim 2, wherein the total amount of the compounds of general formula (3) in which n is 5 is more than 0 ppm and 15 ppm or less, based on the mass of the resin composition.

4. The resin composition according to any one of claims 1 to 3, wherein p and q satisfy 20≦q / (p+q)×100≦80.

5. The resin composition according to any one of claims 1 to 4, wherein a polyimide resin film obtained by curing the resin composition is used for a flexible substrate.

6. The resin composition according to any one of claims 1 to 5, wherein a polyimide resin film obtained by curing the resin composition is used for a flexible display.

7. a coating step of coating the resin composition according to any one of claims 1 to 6 onto 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:

8. The method for producing a polyimide film according to claim 7 , further comprising, prior to the peeling step, an irradiation step of irradiating the resin composition with a laser from the support side.

9. a coating step of coating the resin composition according to any one of claims 1 to 6 onto 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:

10. a coating step of coating the resin composition according to any one of claims 1 to 6 onto 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:

11. The method for producing a laminate according to claim 10 , further comprising the step of peeling off the polyimide resin film on which the element is formed from the support.

12. A method for producing a flexible device, comprising producing a laminate by the method according to claim 10 or 11.

13. A polyimide film which is a cured product of the resin composition according to any one of claims 1 to 6.

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