Polymer compositions, varnishes, and polyimide films

Abstract

A polymer composition containing: a polymer (X) that includes at least one repeating unit selected from the group consisting of repeating units represented by general formula (1) and repeating units represented by general formula (2); and a compound (Y) that is represented by general formula (3) (In formula (1), X1 is a tetravalent group having an alicyclic structure or an aromatic ring. In formula (2), X2 is a tetravalent group having an alicyclic structure or an aromatic ring, and R1 and R2 each independently represents hydrogen, a C1-6 alkyl group, or a C3-9 alkyl silyl group. In formula (3), R3 is at least one moiety selected from the group consisting of C1-30 alkyl groups, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxy ethyl groups and methacryloyloxy ethyl groups, and n is 0-2.).

Description

[Technical Field]

[0001] This invention relates to polymer compositions, varnishes, and polyimide films. [Background technology]

[0002] Due to its excellent mechanical properties and heat resistance, polyimide resins are being explored for various applications in fields such as electrical and electronic components. For example, there is a desire to replace glass substrates used in image display devices such as liquid crystal displays and OLED displays with polyimide film substrates, and development is underway to create polyimide resins that meet the performance requirements of optical materials. However, in recent years, with the increasing sophistication of electronic devices, electronic components have become required to simultaneously meet various performance requirements. Therefore, attempts are being made to add new properties to or enhance the inherent properties of polyimide resins used in displays by incorporating various additives.

[0003] For example, Patent Document 1 discloses a polyimide precursor composition comprising a specific polyamic acid and a specific phosphorus compound, which, in addition to heat resistance and mechanical properties, aims to prevent crystallization and shorten the layer formation time, and which allows for the production of a polyimide film having a large water vapor permeability coefficient by heat treatment of the polyamic acid under conditions where the maximum heating temperature is 300 to 500°C. Furthermore, Patent Document 2 discloses a polyimide precursor composition comprising a polyimide precursor having specific repeating units and a phosphorus compound containing phosphorus atoms, having a boiling point at 1 atmosphere lower than the decomposition temperature and 350°C or lower, for the purpose of obtaining a polyimide having transparency, heat resistance, and a low coefficient of linear thermal expansion. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2016 / 121817 [Patent Document 2] International Publication No. 2015 / 080139 [Overview of the project] [Problems that the invention aims to solve]

[0005] As mentioned above, polyimide films are required to replace glass substrates, and therefore require not only mechanical properties and heat resistance, but also high colorless transparency. However, achieving both of these properties simultaneously is difficult, and even if heat resistance is improved by adding additives, preventing yellowing and other issues remains challenging. Furthermore, in order for polyimide itself to exhibit colorless transparency, aliphatic diamines or fluorine-containing diamines are generally used to suppress the formation of intermolecular or intramolecular charge transfer complexes. However, under harsh conditions such as those exceeding 350°C in the TFT manufacturing process for display manufacturing, aliphatic diamines lack the rigidity of aromatic diamines and therefore do not exhibit heat resistance well, and fluorine-containing diamines also lose their colorless transparency at high temperatures. For this reason, there has been a demand for polyimide films with particularly excellent heat resistance and low yellowness. The present invention has been made in view of these circumstances, and the object of the present invention is to provide a polymer composition that can produce a polyimide film with excellent heat resistance and low yellowness, a varnish containing the composition, and a polyimide film with excellent heat resistance and low yellowness. [Means for solving the problem]

[0006] The inventors have discovered that a polymer composition comprising a specific fluorine-containing diamine, a polymer containing repeating units derived from a tetracarboxylic acid having an alicyclic or aromatic ring structure, and a specific phosphorus compound can solve the above problems, and have completed the invention.

[0007] In other words, the present invention relates to the following [1] to [7]. [1]A polymer composition comprising a polymer (X) containing at least one selected from the group consisting of repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2), and a compound (Y) represented by the following general formula (3). [Chemical formula] (In formula (1), X 1 is a tetravalent group having an alicyclic structure or an aromatic ring.) In formula (2), X 2 is a tetravalent group having an alicyclic structure or an aromatic ring, and R 1 and R 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.) In formula (3), R 3 is at least one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, a phenyl group, an alkoxy group, an acryloyl group, a methacryloyl group, an acryloyloxyethyl group, and a methacryloyloxyethyl group, and n is 0 to 2.) [2]The polymer composition according to [1] above, wherein the repeating unit represented by the formula (1) is 10 mol% or more based on all the repeating units of the polymer (X). [3]The polymer composition according to [1] or [2] above, wherein the repeating unit represented by the formula (2) is 10 mol% or more based on all the repeating units of the polymer (X). [4]The polymer composition according to any one of [1] to [3] above, wherein the content of the compound (Y) is 10 ppm or more and 10,000 ppm or less based on the polymer (X). [5]A varnish obtained by dissolving the polymer composition according to any one of [1] to [4] above in an organic solvent. [6]A polyimide film obtained by applying the varnish according to [5] above onto a support and heating. [7]A method for producing a polyimide film, which comprises applying the varnish according to [5] above onto a support and heating. [Advantages of the Invention]

[0008] According to the present invention, a polymer composition capable of obtaining a polyimide film excellent in heat resistance and low in yellowness, a varnish containing the composition, and a polyimide film excellent in heat resistance and low in yellowness can be provided.

Embodiments for Carrying Out the Invention

[0009] [Polymer Composition] The polymer composition of the present invention includes a polymer (X) containing at least one selected from the group consisting of a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2), and a compound (Y) represented by the following general formula (3).

Chemical formula

[0010] The reason why the polymer composition of the present invention is excellent as a raw material for a polyimide film and the obtained polyimide film has excellent properties such as excellent heat resistance and low yellowness is not clear, but it is considered as follows. The polymer composition of the present invention contains a specific phosphorus compound. It is believed that the phosphorus compound coordinates to the ends of the polyimide obtained by imidizing the polymer, or that the ends of the polyimide react with the phosphorus compound, thereby suppressing terminal side reactions or decomposition degradation, especially at high temperatures. Furthermore, it is believed that the detachment of fluorine derived from fluorine-containing diamines can be suppressed, thereby achieving both heat resistance and low yellowness.

[0011] <Polymer (X)> The polymer (X) contained in the polymer composition of the present invention includes at least one selected from the group consisting of repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2). [ka] (In formula (1), X 1 It is a tetravalent group having an alicyclic or aromatic ring structure. In formula (2), X 2 R is a tetravalent group having an alicyclic or aromatic ring structure, 1 and R 2 Each of these is independently a hydrogen atom, a C1-C6 alkyl group, or a C3-C9 alkylsilyl group.

[0012] The repeating unit represented by the general formula (1) contained in the polymer (X) is preferably the repeating unit represented by the following general formula (1-1). [ka] (In formula (1-1), X 1 (It is a tetravalent group having an alicyclic or aromatic ring structure.)

[0013] The repeating unit represented by the general formula (2) contained in polymer (X) is preferably the repeating unit represented by the following general formula (2-1). [ka] (In formula (2-1), X 2 R is a tetravalent group having an alicyclic or aromatic ring structure, 1 and R 2 Each of these is independently a hydrogen atom, a C1-C6 alkyl group, or a C3-C9 alkylsilyl group.

[0014] The polymer (X) contains at least one selected from the group consisting of repeating units represented by general formula (1) and repeating units represented by general formula (2), but may contain only one of the repeating units represented by general formula (1) or the repeating unit represented by general formula (2), or may contain both. In other words, the polymer composition of the present invention may be a polyimide composition comprising a polyimide containing repeating units represented by the following general formula (1) and a compound (Y) represented by the following general formula (3). [ka] (In formula (1), X 1 R is a tetravalent group having an alicyclic or aromatic ring structure. In formula (3), R 3 n is at least one selected from the group consisting of alkyl groups having 1 to 30 carbon atoms, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxyethyl groups, and methacryloyloxyethyl groups, and n is 0 to 2. A polyamic acid composition may also include a polyamic acid containing repeating units represented by the following general formula (2) and a compound (Y) represented by the following general formula (3). [ka] (In formula (2), X 2 R is a tetravalent group having an alicyclic or aromatic ring structure, 1 and R 2 Each of these is independently a hydrogen atom, a C1-C6 alkyl group, or a C3-C9 alkylsilyl group. In formula (3), R 3n is at least one selected from the group consisting of alkyl groups having 1 to 30 carbon atoms, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxyethyl groups, and methacryloyloxyethyl groups, and n is 0 to 2.

[0015] The polymer (X) preferably contains repeating units represented by the general formula (1), and more preferably contains both repeating units represented by the general formula (1) and repeating units represented by the general formula (2).

[0016] In the above equation (1), X 1 X is a tetravalent group having an alicyclic or aromatic ring structure. 1 Preferably, this is obtained by removing two dicarboxylic acid anhydride portions (four carboxyl group portions) from the tetracarboxylic acid dianhydride that serves as the raw material for constituent unit A, which will be described later. In equation (2) above, X 2 X is a tetravalent group having an alicyclic or aromatic ring structure. 2 Preferably, this is obtained by removing two dicarboxylic acid anhydride portions (four carboxyl group portions) from the tetracarboxylic acid dianhydride that serves as the raw material for constituent unit A, which will be described later. In equation (2) above, R 1 and R 2 Each of these is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, preferably hydrogen.

[0017] (Composition of polymer (X)) As described above, the polymer (X) contains at least one selected from the group consisting of repeating units represented by general formula (1) and repeating units represented by general formula (2). It may contain only one of the repeating units represented by general formula (1) or the repeating unit represented by general formula (2), or both. In particular, from the viewpoint of reducing yellowness and improving transparency, the repeating unit represented by formula (1) is preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, even more preferably 70 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less, relative to the total repeating units of the polymer (X). Furthermore, from the viewpoint of maintaining low yellowness while also improving heat resistance, the repeating units represented by formula (2) are preferably 10 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, even more preferably 70 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less, relative to the total repeating units of the polymer (X). Furthermore, when both the repeating unit represented by general formula (1) and the repeating unit represented by general formula (2) are included, the molar ratio [(1) / (2)] of the repeating unit represented by general formula (1) to the repeating unit represented by general formula (2) is preferably 10 / 90 to 70 / 30, more preferably 20 / 80 to 60 / 40, and even more preferably 25 / 75 to 55 / 45.

[0018] <Each constituent unit of polymer (X)> The polymer (X) includes at least one selected from the group consisting of repeating units represented by the general formula (1) and repeating units represented by the general formula (2), and the constituent units of the polymer are described below.

[0019] Polymer (X) has a constituent unit A derived from tetracarboxylic dianhydride and a constituent unit B derived from diamine. In the repeating unit represented by general formula (1), constituent units A and B form an imide structure, and in the repeating unit represented by general formula (2), constituent units A and B form an amide acid structure. In both cases, the constituent units derived from tetracarboxylic dianhydrides are collectively referred to as constituent unit A, and the constituent units derived from diamines are collectively referred to as constituent unit B.

[0020] (Constituent Unit A) Constituent unit A is a constituent unit derived from a tetracarboxylic dianhydride, and is at least one selected from the group consisting of constituent units derived from alicyclic tetracarboxylic dianhydrides and constituent units derived from aromatic tetracarboxylic dianhydrides. From the viewpoint of low yellowness and transparency, it is preferably a constituent unit derived from an alicyclic tetracarboxylic dianhydride, and from the viewpoint of heat resistance, it is preferably a constituent unit derived from an aromatic tetracarboxylic dianhydride.

[0021] Examples of alicyclic tetracarboxylic dianhydrides that provide structural units derived from alicyclic tetracarboxylic dianhydrides include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyltetracarboxylic dianhydride, 5,5'-(1,4-phenylene)-bis[hexahydro-4,7-Methanoisobenzofuran-1,3-dione], 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic acid-5,5',6,6'-dianhydride, or positional isomers thereof. Among these, from the viewpoint of low yellowness and transparency, the compound is preferably represented by the following formula (a1), and the constituent unit A preferably includes constituent unit (A1) derived from the compound represented by formula (a1). [ka] The compound represented by formula (a1) is norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride.

[0022] Examples of aromatic tetracarboxylic dianhydrides that provide constituent units derived from aromatic tetracarboxylic dianhydrides include biphenyltetracarboxylic dianhydride (BPDA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), pyromellitic dianhydride, 3,3',4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and 2,2',3,3'-benzophenonetetracarboxylic dianhydride. Among these, from the viewpoint of achieving both heat resistance and low yellowness, it is preferably at least one selected from the group consisting of compounds represented by the following formula (a2) and compounds represented by the following formula (a3), and more preferably the compound represented by the following formula (a2). In other words, constituent unit A preferably includes at least one selected from the group consisting of constituent unit (A2) derived from a compound represented by the following formula (a2) and constituent unit (A3) derived from a compound represented by the following formula (a3), and more preferably includes constituent unit (A2) derived from a compound represented by the following formula (a2). [ka]

[0023] The compound represented by formula (a2) is a biphenyltetracarboxylic dianhydride (BPDA), and specific examples include 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by formula (a2s) below, 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) represented by formula (a2a) below, and 2,2',3,3'-biphenyltetracarboxylic dianhydride (i-BPDA) represented by formula (a2i) below. Among these, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by formula (a2s) below is preferred. [ka]

[0024] The compound represented by formula (a3) ​​is 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF).

[0025] Constituent unit A may include constituent units other than aromatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides. Examples of tetracarboxylic dianhydrides that give such constituent units are not particularly limited, but include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride. The constituent units that are optionally included in constituent unit A may be one type or two or more types. In this specification, "aromatic tetracarboxylic dianhydride" means a tetracarboxylic dianhydride containing one or more aromatic rings, "alicyclic tetracarboxylic dianhydride" means a tetracarboxylic dianhydride containing one or more alicyclic rings but no aromatic rings, and "aliphatic tetracarboxylic dianhydride" means a tetracarboxylic dianhydride containing neither aromatic nor alicyclic rings.

[0026] (Constituent unit B) Constituent unit B is a constituent unit derived from a diamine and includes constituent unit (B1) derived from the compound represented by formula (b1). By including constituent unit (B1) within constituent unit B, it exhibits excellent heat resistance, and is particularly effective in reducing yellowness when combined with compound (Y). The ratio of constituent unit (B1) in constituent unit B is preferably 45 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of this ratio is not particularly limited, but is 100 mol% or less. [ka]

[0027] The constituent unit (B1) preferably includes a constituent unit (B11) derived from a compound represented by the following formula (b11), and more preferably the constituent unit (B1) is a constituent unit (B11) derived from a compound represented by the following formula (b11). [ka]

[0028] The compound represented by formula (b11) is 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA). By including constituent unit (B11) within constituent unit B, it exhibits excellent effects in reducing yellowness, especially when combined with compound (Y).

[0029] Constituent unit B may include constituent units other than constituent unit (B1). The diamines that give such constituent units are not particularly limited, but include 4-aminophenyl-4-aminobenzoate (4-BAAB), 3,5-diaminobenzoic acid (3,5-DABA), 9,9-bis(4-aminophenyl)fluorene, 1,4-phenylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, and 4,4'-diamine. Examples include aromatic diamines such as nobenzanilide, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 1,4-bis(4-aminophenoxy)benzene; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

[0030] Among these, the compound is preferably represented by the following formula (b2), and the constituent unit B preferably includes a constituent unit (B2) derived from the compound represented by formula (b2). [ka] The compound represented by formula (b2) is 4-aminophenyl-4-aminobenzoate (4-BAAB).

[0031] In this specification, aromatic diamine means a diamine containing one or more aromatic rings, alicyclic diamine means a diamine containing one or more alicyclic rings but not aromatic rings, and aliphatic diamine means a diamine that does not contain either aromatic or alicyclic rings. The constituent units that are optionally included in constituent unit B may be one type or two or more types.

[0032] (Method for manufacturing polymer (X)) The polymer (X) may be produced by any method, but the following method is preferred. As described above, polymer (X) contains either or both of the repeating units represented by general formula (1) (i.e., the imide moiety) and the repeating units represented by general formula (2) (i.e., the amidic acid moiety), but these can be adjusted by changing the manufacturing method. Specifically, in a manufacturing method (method for producing imido-amidic acid copolymer) that includes both repeating units represented by formula (1) and repeating units represented by formula (2), by using only the step of producing the portion mainly containing the repeating units represented by formula (1) (polyimide portion), a polymer (X) (polyimide) substantially consisting of repeating units represented by formula (1) can be obtained, and by using only the step of producing the portion mainly containing the repeating units represented by formula (2) (polyamidic acid portion), a polymer (X) (polyamidic acid) substantially consisting of repeating units represented by formula (2) can be obtained.

[0033] A polymer (X) (hereinafter also referred to as an imido-amidic acid copolymer) containing both the repeating unit represented by formula (1) and the repeating unit represented by formula (2) is preferably produced by a method having the following steps 1 and 2. Step 1: A step to obtain an imide oligomer by reacting the tetracarboxylic acid component constituting the imide moiety with the diamine component. Step 2: A step in which the imide oligomer obtained in Step 1 is reacted with the tetracarboxylic acid component and the diamine component that constitute the amidic acid portion to obtain an imide-amidic acid copolymer.

[0034] Furthermore, by reacting all the tetracarboxylic acid components with the diamine components in step 1, a polymer (X) (polyimide) consisting substantially of repeating units represented by formula (1) is obtained. Specifically, the method for producing a polymer (X) (polyimide) consisting substantially of repeating units represented by formula (1) is to read step 1 as "a step of reacting the tetracarboxylic acid components constituting the polyimide with the diamine components to obtain the polyimide." Alternatively, by omitting step 1 and reacting all the tetracarboxylic acid components with the diamine components in step 2, a polymer (X) (polyamic acid) consisting substantially of repeating units represented by formula (2) can be obtained. Specifically, the method for producing a polymer (X) (polyamic acid) consisting substantially of repeating units represented by formula (2) is to replace step 2 with "a step of reacting the tetracarboxylic acid components and diamine components constituting polyamic acid to obtain polyamic acid."

[0035] [Process 1] Step 1 is a step in which the tetracarboxylic acid component constituting the imide portion is reacted with the diamine component to obtain an imide oligomer. The tetracarboxylic acid component used in step 1 preferably includes a compound that provides structural unit (A1), and it is preferable that the entire amount is used in step 1. It may also include tetracarboxylic acid components other than the compound that provides structural unit (A1). Among the tetracarboxylic acid components other than the compound that provides structural unit (A1), compounds that provide structural unit (A2) or compounds that provide structural unit (A3) are preferred. The diamine component used in step 1 preferably includes a compound that provides the structural unit (B1), and may also include diamine components other than the compound that provides the structural unit (B1), as long as it does not impair the effects of the present invention. Among the tetracarboxylic acid components other than the compound that provides the structural unit (B1), a compound that provides the structural unit (B2) is preferred. In step 1, the amount of the diamine component relative to the tetracarboxylic acid component is preferably 1.01 to 2 moles, more preferably 1.05 to 1.9 moles, and even more preferably 1.1 to 1.7 moles. Furthermore, when obtaining a polymer (X) (polyimide) consisting substantially of repeating units represented by formula (1), the amount of the diamine component relative to the tetracarboxylic acid component is preferably 0.9 to 1.1 moles.

[0036] There are no particular restrictions on the method for reacting the tetracarboxylic acid component with the diamine component to obtain the imide oligomer in step 1; known methods can be used. Specific reaction methods include: (1) charging the tetracarboxylic acid component, diamine component, and reaction solvent into a reactor, stirring at 10-110°C for 0.5-30 hours, and then raising the temperature to carry out the imidation reaction; (2) charging the diamine component and reaction solvent into a reactor and dissolving them, then charging the tetracarboxylic acid component, stirring at 10-110°C for 0.5-30 hours as needed, and then raising the temperature to carry out the imidation reaction; and (3) charging the tetracarboxylic acid component, diamine component, and reaction solvent into a reactor and immediately raising the temperature to carry out the imidation reaction.

[0037] In the imidation reaction, it is preferable to carry out the reaction while removing the water generated during production using a Dean-Stark apparatus or similar device. By performing such an operation, the degree of polymerization and the imidation rate can be further increased.

[0038] In the above imidation reaction, known imidation catalysts can be used. Examples of imidation catalysts include base catalysts and acid catalysts. Examples of base catalysts include organic base catalysts such as pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline, as well as inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. The above imidation catalysts may be used individually or in combination of two or more types. Of the above, from the viewpoint of ease of handling, a base catalyst is preferred, an organic base catalyst is more preferred, one or more selected from triethylamine and triethylenediamine are even more preferred, and triethylamine is even more preferred.

[0039] The temperature of the imidation reaction is preferably 120 to 250°C, more preferably 160 to 200°C, from the viewpoint of the reaction rate and suppression of gelation, etc. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the generated water.

[0040] The imide oligomer obtained in step 1 preferably has an imide repeating structural unit formed from a compound that gives structural unit (A1) and a compound that gives structural unit (B1). By the above method, a solution containing an imide oligomer dissolved in a solvent is obtained. The solution containing the imide oligomer obtained in step 1 may contain at least a portion of the components used as tetracarboxylic acid components and diamine components in step 1 as unreacted monomers, to the extent that the effects of the present invention are not impaired.

[0041] [Process 2] Step 2 in the manufacturing method of the present invention is a step of reacting the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and the diamine component that constitute the amidic acid portion to obtain an imide-amidic acid copolymer.

[0042] The tetracarboxylic acid component used in step 2 preferably includes a compound that provides structural unit (A1), and it is preferable that the entire amount is used in step 1. It may also include tetracarboxylic acid components other than the compound that provides structural unit (A1). Among the tetracarboxylic acid components other than the compound that provides structural unit (A1), compounds that provide structural unit (A2) or compounds that provide structural unit (A3) are preferred. The diamine component used in step 2 preferably includes a compound that provides the structural unit (B1), and may also include diamine components other than the compound that provides the structural unit (B1), as long as it does not impair the effects of the present invention. Among the tetracarboxylic acid components other than the compound that provides the structural unit (B1), a compound that provides the structural unit (B2) is preferred. Furthermore, when obtaining a polymer (X) (polyamic acid) consisting substantially of repeating units represented by formula (2) by performing only step 2, it is preferable that the amount of the diamine component relative to the tetracarboxylic acid component be 0.9 to 1.1 moles.

[0043] There are no particular restrictions on the method of reacting the tetracarboxylic acid component and the diamine component with the imide oligomer obtained in step 1 in step 2; known methods can be used. Specific reaction methods include (1) charging the imide oligomer, tetracarboxylic acid component, diamine component, and solvent obtained in step 1 into a reactor and stirring at 0 to 120°C, preferably 5 to 80°C, for 1 to 72 hours, and (2) charging the imide oligomer and solvent obtained in step 1 into a reactor and dissolving them, then charging the tetracarboxylic acid component and diamine component, and stirring at 0 to 120°C, preferably 5 to 80°C, for 1 to 72 hours. When the reaction is carried out at a temperature of 80°C or lower, the molecular weight of the copolymer obtained in step 2 does not fluctuate depending on the temperature history during polymerization, and the progress of thermal imidization can also be suppressed, thus enabling the stable production of the copolymer.

[0044] By the above method, a copolymer solution containing an imide-amidic acid copolymer dissolved in a solvent is obtained. Furthermore, a polyimide solution containing polyimide can be obtained by performing only step 1, and a polyamidic acid solution containing polyamidic acid can be obtained by performing only step 2. The concentration of the copolymer in the resulting solution is typically 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 5 to 30% by mass. Furthermore, the concentration of polyimide in the resulting solution is typically 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 5 to 30% by mass. Furthermore, the concentration of polyamic acid in the resulting solution is typically 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 5 to 30% by mass.

[0045] The number-average molecular weight of the imido-amidic acid copolymer obtained by the above manufacturing method is preferably 5,000 to 500,000, from the viewpoint of the mechanical strength of the resulting polyimide film. Similarly, the weight-average molecular weight (Mw) is preferably 10,000 to 800,000, and more preferably 100,000 to 300,000. The number-average molecular weight and weight-average molecular weight of the copolymer can be determined, for example, from the standard polymethyl methacrylate (PMMA) equivalent value obtained by gel filtration chromatography. The number-average molecular weight of the polyimide obtained by the above manufacturing method is preferably 5,000 to 500,000, from the viewpoint of the mechanical strength of the resulting polyimide film. Similarly, the weight-average molecular weight (Mw) is preferably 10,000 to 800,000, and more preferably 100,000 to 300,000. The number-average molecular weight of the polyamic acid obtained by the above manufacturing method is preferably 5,000 to 500,000, from the viewpoint of the mechanical strength of the resulting polyimide film. Similarly, the weight-average molecular weight (Mw) is preferably 10,000 to 800,000, and more preferably 100,000 to 300,000. Next, we will explain the raw materials and other components used in this manufacturing method.

[0046] [Tetracarboxylic acid component] As a tetracarboxylic acid component used as a raw material in this manufacturing method, the compound that gives the constituent unit (A1) is the compound represented by formula (a1), but is not limited to that, and derivatives thereof may also be used as long as they give the same constituent unit. Examples of such derivatives include the tetracarboxylic acid corresponding to the compound represented by formula (a1) and the alkyl ester of said tetracarboxylic acid. The compound represented by formula (a1) is preferred as the compound that gives the constituent unit (A1). Similarly, examples of compounds that provide the structural unit (A2) include, but are not limited to, the compound represented by formula (a2), and derivatives thereof that provide the same structural unit may also be used. Examples of such derivatives include the tetracarboxylic acid corresponding to the compound represented by formula (a2) and the alkyl ester of the tetracarboxylic acid. The compound represented by formula (a2) is preferred as the compound that provides the structural unit (A2). Furthermore, while compounds that provide the structural unit (A3) include, but are not limited to, compounds represented by formula (a3), derivatives thereof may also be used as long as they provide the same structural unit. Examples of such derivatives include tetracarboxylic acids corresponding to the compound represented by formula (a3) ​​and alkyl esters of said tetracarboxylic acids. The compound represented by formula (a3) ​​is preferred as the compound that provides the structural unit (A3).

[0047] [Diamine components] In this manufacturing method, diamines are used as raw materials, and compounds that provide the structural unit (B1) include, but are not limited to, diamines, and derivatives thereof that provide the same structural unit may also be used. Examples of such derivatives include diisocyanates corresponding to diamines. Diamines are preferred as the compound that provides the structural unit (B1). Similarly, examples of compounds that provide the structural unit (B2) include diamines, but are not limited to them; derivatives thereof that provide the same structural unit may also be used. Examples of such derivatives include diisocyanates corresponding to diamines. Diamines are preferred as the compounds that provide the structural unit (B2).

[0048] In the present invention, the preferred ratio of the tetracarboxylic acid component to the diamine component used in all steps of the copolymer manufacturing process, including steps 1 and 2, is 0.9 to 1.1 moles of the diamine component per mole of the tetracarboxylic acid component.

[0049] [End-tidal encapsulant] Furthermore, in addition to the tetracarboxylic acid component and diamine component mentioned above, an end-capturing agent may also be used in the production of polymer (X). If both steps 1 and 2 are performed, the end-capturing agent is preferably used in step 2. Monoamines or dicarboxylic acids are preferred as end-cap encapsulants. The amount of end-cap encapsulant to be introduced is preferably 0.0001 to 0.1 moles per mole of tetracarboxylic acid component, and particularly preferably 0.001 to 0.06 moles. Recommended monoamine end-cap encapsulants include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, and 4-methylaniline. Of these, benzylamine and aniline can be suitably used. Dicarboxylic acids are preferred as end-cap encapsulants, and some of them may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid are recommended. Of these, phthalic acid and phthalic anhydride can be preferably used.

[0050] 〔solvent〕 The solvent used in the method for producing polymer (X) can be any solvent capable of dissolving the resulting imido-amidic acid copolymer. Examples include aprotic solvents, phenolic solvents, etheric solvents, and carbonate solvents.

[0051] Specific examples of aprotic solvents include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, and tetramethylurea; lactone solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide solvents such as hexamethylphosphoricamide and hexamethylphosphinetriamide; sulfur-containing solvents such as dimethylsulfone, dimethyl sulfoxide, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methylcyclohexanone; and ester solvents such as acetic acid (2-methoxy-1-methylethyl).

[0052] Specific examples of phenolic solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol. Specific examples of ether-based solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane. Specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate. Among the above reaction solvents, amide solvents or lactone solvents are preferred, amide solvents are more preferred, and N-methyl-2-pyrrolidone is even more preferred. The above reaction solvents may be used individually or in combination of two or more.

[0053] <Compound (Y)> The compound (Y) contained in the polymer composition of the present invention is represented by the following general formula (3). [ka] (In formula (3), R 3 n is at least one selected from the group consisting of alkyl groups having 1 to 30 carbon atoms, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxyethyl groups, and methacryloyloxyethyl groups, and n is 0 to 2. By including compound (Y), it is possible to obtain a film that is heat-resistant, has low yellowness, and further improves the transparency of the film.

[0054] In equation (3), R 3 The group is at least one selected from the group consisting of C1-C30 alkyl groups, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxyethyl groups, and methacryloyloxyethyl groups, and is preferably a C1-C30 alkyl group. Multiple R 3 They may be the same or different, but are preferably the same. n is between 0 and 2, preferably between 1 and 2.

[0055] Compound (Y) is a phosphorus compound, and specific examples of compound (Y) include at least one selected from the group consisting of acidic phosphate esters and phosphoric acid, with acidic phosphate esters being preferred. Examples of acidic phosphate esters include isotridecyl acid phosphate and dibutyl phosphate, with isotridecyl acid phosphate being preferred.

[0056] The content of compound (Y) is preferably 10 ppm to 10,000 ppm, more preferably 100 ppm to 5,000 ppm, and even more preferably 500 ppm to 2,000 ppm, relative to polymer (X). By having compound (Y) within this range, a film with low yellowness while possessing heat resistance can be obtained, and the transparency of the film can also be improved. In this specification, "ppm" represents parts per million by mass.

[0057] [varnish] The varnish of the present invention is obtained by dissolving the above-mentioned polymer composition in an organic solvent. That is, the varnish of the present invention is obtained by dissolving the polymer (X) and compound (Y) in an organic solvent, and the varnish of the present invention contains the polymer (X), compound (Y), and organic solvent, with the polymer (X) and compound (Y) being dissolved in the organic solvent. The organic solvent can be any solvent that dissolves the polymer (X) and compound (Y), and is not particularly limited. However, it is preferable to use the above-mentioned compounds individually or in a mixture of two or more as the solvent used in the production of the polymer (X). The varnish of the present invention may be obtained by mixing and dissolving compound (Y) in the polymer (X) solution described above, or by adding a diluent solvent.

[0058] If the polymer (X) contained in the varnish of the present invention contains a repeating unit (amidic acid portion) represented by formula (2), an imidation catalyst and a dehydration catalyst may be further included from the viewpoint of efficiently promoting the imidation of the amidic acid portion. The imidation catalyst can be any imidation catalyst having a boiling point of 40°C or higher and 180°C or lower, and amine compounds with a boiling point of 180°C or lower are preferred. If an imidation catalyst with a boiling point of 180°C or lower is used, there is no risk of the film becoming discolored and its appearance being impaired during high-temperature drying after film formation. Furthermore, if an imidation catalyst with a boiling point of 40°C or higher is used, the possibility of volatilization before sufficient imidation has progressed can be avoided. Suitable amine compounds to be used as imidation catalysts include pyridine and picoline. These imidation catalysts may be used individually or in combination of two or more. Examples of dehydration catalysts include acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride; and carbodiimide compounds such as dicyclohexylcarbodiimide. These may be used individually or in combination of two or more.

[0059] Since the polymer (X) contained in the varnish of the present invention is solvent-soluble, a high-concentration varnish can be produced. The varnish of the present invention preferably contains 3 to 40% by mass of polymer (X), more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass. The viscosity of the varnish is preferably 0.1 to 100 Pa·s, and more preferably 0.1 to 20 Pa·s. The viscosity of the varnish is the value measured at 25°C using an E-type viscometer. Furthermore, the varnish of the present invention may contain various additives such as inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, surfactants, leveling agents, defoamers, fluorescent whitening agents, crosslinking agents, polymerization initiators, and photosensitive agents, to the extent that they do not impair the required properties of the polyimide film. The method for producing the varnish of the present invention is not particularly limited, and known methods can be applied.

[0060] [Polyimide film and method for manufacturing polyimide film] The polyimide film of the present invention includes a polyimide resin obtained by imidizing the amide acid portion of polymer (X) when the polymer (X) contains repeating units (amide acid portion) represented by formula (2), and compound (Y). Furthermore, when polymer (X) is polyimide, the film includes the polyimide, or a polyimide resin obtained by further adjusting the molecular weight by heating, and compound (Y). Therefore, the polyimide film of the present invention has excellent heat resistance and low yellowness. The polyimide film of the present invention can be manufactured using the aforementioned varnish.

[0061] There are no particular limitations on the method for producing a polyimide film using the varnish of the present invention, but the following method is preferred. In other words, a method of applying the above-mentioned varnish onto a support and heating it is preferred, and more specifically, a method of applying a varnish in which the polymer (X) and compound (Y) are dissolved in an organic solvent onto a support and heating it is preferred. Furthermore, the polyimide film of the present invention is preferably a polyimide film obtained by coating the above-mentioned varnish onto a support and heating it. Specifically, a polyimide film obtained by coating a support with a varnish in which a polymer (X) and a compound (Y) are dissolved in an organic solvent and heating it is preferred.

[0062] Examples of support materials include smooth glass plates, metal plates, and plastics. A polyimide film can be produced by applying a varnish to a support or forming it into a film, then removing organic solvents such as reaction solvents and diluent solvents contained in the varnish by heating to obtain a polymer film, and if the polymer contained in the polymer film contains an amide acid portion, imidizing it (dehydration and ring closure) by heating, and then peeling it off the support. The weight-average molecular weight (Mw) of the polyimide resin contained in the polyimide film of the present invention is preferably 10,000 to 800,000, more preferably 30,000 to 500,000, even more preferably 50,000 to 400,000, and even more preferably 100,000 to 300,000, from the viewpoint of the mechanical strength of the film. The weight-average molecular weight of the copolymer can be determined, for example, from the value converted to standard polymethyl methacrylate (PMMA) by gel filtration chromatography.

[0063] The heating temperature for drying the varnish of the present invention to obtain a polymer film is preferably 50 to 150°C. The heating temperature for imidizing the polymer by heating is preferably 200 to 500°C, more preferably 250 to 450°C, and even more preferably 300 to 400°C. The heating time is usually 1 minute to 6 hours, preferably 5 minutes to 2 hours, and more preferably 15 minutes to 1 hour. Examples of heating atmospheres include air, nitrogen gas, oxygen gas, hydrogen gas, and nitrogen / hydrogen mixed gas. However, in order to suppress discoloration of the resulting polyimide resin, nitrogen gas with an oxygen concentration of 100 ppm or less and nitrogen / hydrogen mixed gas with a hydrogen concentration of 0.5% or less are preferred. Furthermore, the imidation method is not limited to thermal imidation; chemical imidation can also be applied.

[0064] The thickness of the polyimide film of the present invention can be appropriately selected depending on the application, but is preferably 1 to 250 μm, more preferably 5 to 100 μm, and even more preferably 5 to 50 μm. A thickness of 1 to 250 μm enables practical use as a self-supporting film. The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and viscosity of the varnish.

[0065] By using the polymer composition of the present invention, a polyimide film with excellent heat resistance and low yellowness can be obtained. The resulting polyimide film of the present invention has excellent heat resistance and low yellowness. The preferred physical properties of the film are as follows. The total light transmittance is preferably 85% or more, more preferably 87% or more, and even more preferably 89% or more, when the film has a thickness of 10 μm. The yellow index (YI), when applied to a 10 μm thick film, is preferably 12 or less, more preferably 11 or less, and from the viewpoint of excellent colorlessness, preferably 9 or less, more preferably 8 or less. Furthermore, the 1% weight loss temperature is preferably 430°C or higher, more preferably 480°C or higher, even more preferably 500°C or higher, and even more preferably 510°C or higher. Here, the 1% weight loss temperature is the temperature at which the weight of the polyimide film decreases by 1% when heated to 40-550°C at a heating rate of 10°C / min compared to the weight at 300°C. The above-mentioned physical properties in this invention can be specifically measured by the methods described in the examples.

[0066] The polyimide film of the present invention is suitably used as a film for various components such as color filters, flexible displays, semiconductor components, and optical components. The polyimide film of the present invention is particularly suitably used as a substrate for image display devices such as liquid crystal displays and OLED displays. [Examples]

[0067] The present invention will be specifically described below with reference to examples. However, the present invention is not limited in any way by these examples. The physical properties of the films obtained in the examples and comparative examples were measured by the following methods.

[0068] (1) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Corporation. The film thicknesses for Example 5 and Comparative Example 6 were measured using a Filmetrics F20 film thickness measuring instrument (manufactured by Filmetrics Co., Ltd.).

[0069] (2) Total light transmittance, Yellow Index (YI) Total light transmittance was measured in accordance with JIS K7105:1981, and YI was measured in accordance with ASTM D1925 (C light source, 2°) using the COH7700 color and turbidity simultaneous measuring instrument manufactured by Nippon Denshoku Industries Co., Ltd.

[0070] (3) 1% weight loss temperature (Td1%) A differential thermogravimetric analyzer, "NEXTA STA200RV," manufactured by Hitachi High-Tech Science Corporation, was used. The sample was heated from 40 to 150°C at a heating rate of 10°C / min, held at 150°C for 30 minutes to remove moisture, and then heated to 550°C. The temperature at which the weight decreased by 1% compared to the weight after holding at 150°C for 30 minutes was defined as the 1% weight loss temperature. A higher weight loss temperature indicates better performance.

[0071] The tetracarboxylic acid and diamine components used in the examples and comparative examples, as well as their abbreviations, are as follows. <Tetracarboxylic acid component> CpODA: norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride (compound represented by formula (a1)) s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation, represented by formula (a2s)) BPAF: 9,9-Bis(3,4-Dicarboxyphenyl)fluorene dianhydride (manufactured by JFE Chemical Corporation; compound represented by formula (a3)) <Diamine component> 6FODA: 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (compound represented by formula (b11)) 4-BAAB: 4-aminophenyl-4-aminobenzoate (manufactured by Nippon Junryo Pharmaceutical Co., Ltd.; compound represented by formula (b2)) <Phosphorus compounds> JP-513: Isotridecyl acid phosphate (manufactured by Johoku Chemical Industry Co., Ltd., in formula (3), R 3 A compound in which is an isotridecyl group and n is 1, and R 3 (A 1:1 mixture of compounds in which the isotridecyl group is n = 2) DBP: Dibutyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., in formula (3), R 3 (A compound in which n is 2 and is a butyl group) Phosphate: Compounds in formula (3) where n is 0 Trimethyl phosphate: In formula (3), R 3 Compounds in which n is 3 and is a methyl group. Triphenylphosphine: In formula (3), R 3 Compounds in which n is 3 and is a phenyl group. <Other compounds> Irganox 1010 (antioxidant): Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF Japan Ltd.) <Surface modifier> BYK-378: Silicone-based surface modifier (manufactured by Bic Chemie Japan Co., Ltd.)

[0072] The abbreviations for the solvents and catalysts used in the examples and comparative examples are as follows. NMP: N-methyl-2-pyrrolidone (manufactured by Tokyo Pure Chemical Industries, Ltd.) TEA: Triethylamine (manufactured by Kanto Chemical Co., Ltd.)

[0073] <Example 1> In a 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, nitrogen inlet tube, condenser, thermometer, and glass end cap, 26.899 g (0.0800 mol) of 6FODA and 94.146 g of NMP were added, and the mixture was stirred at 200 rpm under a nitrogen atmosphere at a system temperature of 50°C to obtain the solution. To this solution, 23.536 g (0.0800 mol) of s-BPDA and 23.536 g of NMP were added all at once, and the mixture was stirred for 5 hours while maintaining a temperature of 50°C using a mantle heater. Subsequently, 84.059 g of NMP was added and homogenized, and then the mixture was returned to room temperature to obtain a polyamic acid varnish with a solid content of 20% by mass. To 100g of the obtained varnish, 0.02g of JP-513 (1000ppm relative to the polyamic acid) and 0.02g of BYK-378 (1000ppm relative to the polyamic acid) were added and the mixture was stirred for 30 minutes to homogenize it, thereby obtaining a polyamic acid composition varnish. Next, the obtained polyamic acid composition varnish was applied to a glass plate by spin coating, held at 80°C for 20 minutes on a hot plate, and then transferred to a hot air dryer. Under a nitrogen atmosphere, the temperature was raised to 420°C at a heating rate of 5°C / min, and then heated at 420°C in the hot air dryer under a nitrogen atmosphere for 60 minutes to evaporate the solvent and imideize the material, obtaining a polyimide film. The results are shown in Table 1.

[0074] <Examples 2, 3 and Comparative Examples 2-4> A polyimide film was obtained in the same manner as in Example 1, except that 0.02 g (1000 ppm relative to polyamic acid) of the phosphorus compound or other compound shown in Table 1 was used instead of 0.02 g (1000 ppm relative to polyamic acid). The results are shown in Table 1.

[0075] <Comparative Example 1> A polyimide film was obtained using the same method as in Example 1, except that JP-513 was not used. The results are shown in Table 1.

[0076] <Example 4> A polyamic acid composition varnish was obtained by the same method as in Example 1, except that 0.0800 moles of CpODA were used instead of 23.536 g (0.0800 moles) of s-BPDA, the holding temperature after adding the raw materials all at once was set to 10°C, and the mixture was stirred for 5 hours. Next, the obtained polyamic acid composition varnish was applied to a glass plate by spin coating, held at 80°C for 20 minutes on a hot plate, and then transferred to a hot air dryer. Under a nitrogen atmosphere, the temperature was raised to 420°C at a heating rate of 5°C / min, and then heated at 420°C in the hot air dryer under a nitrogen atmosphere for 60 minutes to evaporate the solvent and imideize the material, obtaining a polyimide film. The results are shown in Table 1.

[0077] <Comparative Example 5> A polyimide film was obtained using the same method as in Example 4, except that JP-513 was not used. The results are shown in Table 1.

[0078] <Example 5> In a 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, nitrogen inlet tube, condenser, thermometer, and glass end cap, 10.087 g (0.030 mol) of 6FODA and 47.017 g of NMP were added, and the mixture was stirred at 200 rpm under a nitrogen atmosphere at a system temperature of 70°C to obtain the solution. To this solution, 9.169 g (0.020 mol) of BPAF and 11.754 g of NMP were added in a single addition. Then, 0.101 g of TEA was added as an imidation catalyst, and the mixture was heated with a mantle heater, raising the reaction system temperature to 190°C over approximately 20 minutes. The components removed by distillation were collected, and the reaction system temperature was maintained at 190°C while refluxing for 1 hour, adjusting the rotation speed according to the increase in viscosity. Subsequently, 147.043 g of NMP was added, and the reaction system temperature was cooled to 50°C to obtain a solution containing oligomers having imide repeating structural units. To the obtained solution, 23.538 g (0.080 mol) of s-BPDA, 15.978 g (0.070 mol) of 4-BAAB, and 26.386 g of NMP were added all at once, and the mixture was stirred at 50°C for 5 hours. Subsequently, NMP was added to homogenize the mixture until the solid content concentration reached approximately 15% by mass, thereby obtaining a varnish containing a copolymer having imide repeating structural units and amide acid structural units (imide-amide acid copolymer varnish). To 100g of the obtained varnish, 0.015g of JP-513 (1000ppm relative to the imido-amidic acid copolymer) and 0.015g of BYK-378 (1000ppm relative to the imido-amidic acid copolymer) were added and the mixture was stirred for 30 minutes to homogenize it, thereby obtaining an imido-amidic acid copolymer varnish composition. Next, the obtained imido-amidic acid copolymer composition varnish was applied to a glass plate by spin coating, held at 80°C for 20 minutes on a hot plate, and then transferred to a hot air dryer. Under a nitrogen atmosphere, the temperature was raised to 430°C at a heating rate of 5°C / min, and then heated at 430°C in the hot air dryer under a nitrogen atmosphere for 60 minutes to evaporate the solvent and thermal imidize, thereby obtaining a polyimide film. The results are shown in Table 1.

[0079] <Comparative Example 6> A polyimide film was obtained using the same method as in Example 5, except that JP-513 was not used. The results are shown in Table 1. In Comparative Example 6, the polyimide film obtained could not be peeled from the glass plate; therefore, the total light transmittance and yellow index (YI) of Example 5 and Comparative Example 6 were measured including the glass plate. Furthermore, the 1% weight loss temperature (Td1%) was not measured for the polyimide film obtained in Comparative Example 6.

[0080] [Table 1]

[0081] As shown in Table 1, the polyimide film obtained from the polymer composition of the present invention exhibits excellent heat resistance and low yellowness. Furthermore, the polyimide film obtained from the polymer composition of the present invention also exhibits excellent transparency.

Claims

1. A polymer (X) comprising at least one selected from the group consisting of repeating units represented by the following general formula (1) and repeating units represented by the following general formula (2), The compound (Y) is represented by the following general formula (3), A polymer composition in which the repeating unit represented by formula (1) is 10 mol% or more of the total repeating units of the polymer (X). 【Chemistry 1】 (In formula (1), X 1 It is a tetravalent group having an alicyclic or aromatic ring structure. In formula (2), X 2 R is a tetravalent group having an alicyclic or aromatic ring structure, 1 and R 2 Each of these is independently a hydrogen atom, a C1-C6 alkyl group, or a C3-C9 alkylsilyl group. In formula (3), R 3 n is at least one selected from the group consisting of alkyl groups having 1 to 30 carbon atoms, phenyl groups, alkoxy groups, acryloyl groups, methacryloyl groups, acryloyloxyethyl groups, and methacryloyloxyethyl groups, and n is 0 to 2.

2. The polymer composition according to claim 1, wherein the repeating unit represented by formula (2) is 10 mol% or more of the total repeating units of the polymer (X).

3. The polymer composition according to claim 1 or 2, wherein the content of compound (Y) is 10 ppm or more and 10,000 ppm or less relative to the polymer (X).

4. A varnish obtained by dissolving the polymer composition according to any one of claims 1 to 3 in an organic solvent.

5. A polyimide film obtained by applying the varnish described in claim 4 onto a support and heating it.

6. A method for producing a polyimide film, comprising applying the varnish described in claim 4 onto a support and heating it.

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