TWI778125B - Polyimide, polyimide varnish, and polyimide film - Google Patents

Abstract

The present invention provides a polyimide in which a structural unit A derived from a tetracarboxylic acid or a derivative thereof includes a structural unit (A-1) derived from a compound (a-1), a structural unit B derived from a diamine includes a structural unit (B-1) derived from a compound (b-1), a structural unit (B-2) derived from a compound (b-2), and at least one structural unit selected from among structural units (B-3) to (B-5) derived from compounds (b-3) to (b-5) respectively, wherein relative to the structural unit B, the proportion of the structural unit (B-1) is less than 50 mol%, the proportion of the structural unit (B-2) is at least 15 mol%, and the proportion accounted for by the combination of the structural unit (B-1) and the structural unit (B-2) is at least 50 mol%, as well as providing a polyimide film containing the above polyimide, a polyimide that can form a film having low retardation and excellent elongation, and a polyimide varnish and polyimide film that contain the polyimide.

Description

Polyimide, Polyimide Varnish and Polyimide Film

The present invention relates to polyimide, and polyimide varnishes and polyimide films comprising the polyimide.

Polyimide has excellent heat resistance, and has excellent mechanical properties, chemical resistance, electrical properties, etc., so it is used in molding materials, composite materials, electrical-electronic parts, optical materials, displays, aerospace and other fields. Among them, films made of polyimide are widely used. It has been discussed to use plastic films instead of glass substrates in optical devices represented by liquid crystal displays (LCDs) in order to achieve light weight, thinning, and flexibility. The difference is small and the phase delay is low.

For plastic film materials that can meet the above requirements, for example, Patent Document 1 discloses the use of 1,2,4,5-cyclohexanetetracarboxylic dianhydride as the tetracarboxylic acid component, and the use of 9,9- Polyimide etc. which are synthesized by bis(3-methyl-4-aminophenyl) fluoride and 4,4'-diaminodiphenyl ether as diamine components. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6010533

[The problem to be solved by the invention]

However, although the polyimide disclosed in Patent Document 1 is excellent in transparency and heat resistance and has a small retardation, the elongation, which is one of the indicators of toughness and toughness, has not reached a satisfactory level. In order to achieve a thin plastic film In order to be flexible and flexible, further improvement is necessary. That is, the subject to be solved by the present invention is to provide a polyimide that can form a film having low retardation and excellent stretchability, and a polyimide varnish and a polyimide film containing the polyimide. [Means of Solving Problems]

As a result of intensive research, the present inventors found that a polyimide composed of a specific structural unit can form a thin film with low retardation and excellent stretchability. Based on these findings, the present invention has been completed. That is, the present invention relates to the following [1] to [3]. [1] A polyimide having a structural unit A derived from a tetracarboxylic acid or a derivative thereof and a structural unit B derived from a diamine, The structural unit A includes the structural unit (A-1) derived from the compound represented by the following formula (a-1), The constitutional unit B includes a constitutional unit (B-1) derived from a compound represented by the following formula (b-1), a constitutional unit (B-2) derived from a compound represented by the following formula (b-2), and a constitutional unit (B-2) selected from the following Structural unit (B-3) of compound represented by formula (b-3), constituent unit (B-4) derived from compound represented by following formula (b-4), and compound derived from compound represented by following formula (b-5) at least one of the constituent units (B-5), The ratio of the constituent unit (B-1) to the constituent unit B is less than 50 mol %, the ratio of the constituent unit (B-2) to the constituent unit B is 15 mol % or more, and the constituent unit (B-1) and The ratio of the total of the structural units (B-2) to the structural unit B is 40 mol % or more.

[化2]

式(b-1)中，R各別獨立地表示氫原子、氟原子或甲基。[hua 1]

[hua 2]

In formula (b-1), R each independently represents a hydrogen atom, a fluorine atom or a methyl group.

[2] A polyimide varnish obtained by dissolving the polyimide according to the above [1] in an organic solvent. [3] A polyimide film comprising the polyimide according to the aforementioned [1]. [Effect of invention]

According to the present invention, a polyimide film capable of forming a film with low retardation and excellent elongation, and a polyimide varnish and a polyimide film comprising the polyimide can be provided.

The polyimide of the present invention has a structural unit A derived from tetracarboxylic acid or a derivative thereof and a structural unit B derived from a diamine, The structural unit A includes the structural unit (A-1) derived from the compound represented by the above formula (a-1), The constitutional unit B includes the constitutional unit (B-1) derived from the compound represented by the above formula (b-1), the constitutional unit (B-2) derived from the compound represented by the above formula (b-2), and selected from the above The structural unit (B-3) of the compound represented by the formula (b-3), the structural unit (B-4) derived from the compound represented by the above formula (b-4), and the compound represented by the above formula (b-5) at least one of the constituent units (B-5), The ratio of the constituent unit (B-1) to the constituent unit B is less than 50 mol %, the ratio of the constituent unit (B-2) to the constituent unit B is 15 mol % or more, and the constituent unit (B-1) and The ratio of the total of the structural units (B-2) to the structural unit B is 40 mol % or more. Hereinafter, the polyimide of the present invention will be described.

[Constituent Unit A] The structural unit A contained in the polyimide of the present invention is a structural unit derived from a tetracarboxylic acid or a derivative thereof. A tetracarboxylic acid or its derivative(s) can be used individually or in combination of 2 or more types. As the derivatives of tetracarboxylic acids, anhydrides or alkyl esters of tetracarboxylic acids can be mentioned. As for the alkyl ester of a tetracarboxylic acid, it is preferable that the carbon number of an alkyl group is 1-3, For example, the dimethyl ester of a tetracarboxylic acid, a diethyl ester, and a dipropyl ester are mentioned. As a tetracarboxylic acid or its derivative(s), tetracarboxylic dianhydride is preferable. The structural unit A in the present invention includes the structural unit (A-1) derived from the compound represented by the following formula (a-1). The compound represented by formula (a-1) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride. When the structural unit A includes the structural unit (A-1), the transparency and heat resistance of the polyimide are improved.

[hua 3]

The proportion of the constituent unit (A-1) relative to the constituent unit A is preferably 70-100 mol %, more preferably 85-100 mol %, more preferably 99-100 mol %, still more preferably 100 mol % better.

The polyimide of the present invention may include, as the aforementioned structure, a structural unit derived from a tetracarboxylic dianhydride other than the compound represented by the formula (a-1) in the structural unit A within the range that does not impair the effects of the present invention. Structural units other than the unit (A-1) are preferably not included.

[Constituent Unit B] The structural unit B contained in the polyimide of the present invention is a structural unit derived from a diamine. The aforementioned structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1).

[hua 4]

In the above formula (b-1), R is independently selected from the group consisting of a hydrogen atom, a fluorine atom, and a methyl group, and is preferably a hydrogen atom. Examples of the compound represented by the above formula (b-1) include 9,9-bis(4-aminophenyl)fluoride, 9,9-bis(3-fluoro-4-aminophenyl)fluoride , and 9,9-bis(3-methyl-4-aminophenyl) fluoride, etc., preferably at least one selected from the group consisting of these three compounds, which is 9,9-bis( 4-aminophenyl) phenyl) is more preferred. By including the aforementioned structural unit (B-1), the polyimide of the present invention can reduce the phase difference and exhibit low phase retardation. In the present invention, the ratio of the structural unit (B-1) to the structural unit B is less than 50 mol %. When the ratio of the said structural unit (B-1) is 50 mol% or more, it becomes difficult to form a thin film which is excellent in extensibility. From the viewpoint of exhibiting low phase retardation and forming a thin film with excellent stretchability, the ratio of the aforementioned constituent unit (B-1) is preferably 45 mol % or less, more preferably 42 mol % or less, and even more preferably 40 mol % or less. Preferably, it is 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more. Considering the same viewpoint as above, the ratio of the aforementioned constituent unit (B-1) is preferably 5 to 45 mol %, preferably 10 to 45 mol %, more preferably 15 to 45 mol %, and more preferably 20 to 20 mol %. 40 mol% is even better.

The structural unit B in the present invention includes the structural unit (B-2) derived from the compound represented by the following formula (b-2).

[hua 5]

The compound represented by the above formula (b-2) is 2,2-bis[4-(4-aminophenoxy)phenyl]propane. Since the polyimide of the present invention contains the aforementioned structural unit (B-2), the retardation can be reduced, and a thin film having excellent low retardation and excellent stretchability can be formed. In this invention, the ratio of the said structural unit (B-2) with respect to the structural unit B is 15 mol% or more. When the ratio of the aforementioned structural unit (B-2) is less than 15 mol %, it becomes difficult to form a thin film with low retardation and excellent stretchability. Considering the viewpoint of forming a film with low retardation and excellent extensibility, the proportion of the aforementioned constituent unit (B-2) is preferably 20 mol % or more, more preferably 25 mol % or more, and even more preferably 30 mol % or more , more preferably 35 mol% or more, more preferably 40 mol% or more, and preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. Considering the same viewpoint as above, the ratio of the aforementioned constituent unit (B-2) is preferably 15-70 mol %, more preferably 15-60 mol %, more preferably 20-50 mol %, 30-30 mol % 50 mol % is still better, 35-50 mol % is still better, 40-50 mol % is still more preferred.

In the present invention, the ratio of the total of the structural units (B-1) and (B-2) to the structural unit B is 40 mol % or more. If the ratio of the total of the aforementioned constituent units (B-1) and (B-2) is less than 40 mol %, it will be difficult to form a thin film with low retardation and excellent stretchability. The proportion of the total of the aforementioned constituent units (B-1) and (B-2) is preferably 50 mol % or more, more preferably 55 mol % or more, more preferably 60 mol % or more, and preferably 95 mol % or less, more preferably 90 mol % or less. Considering the same viewpoint as above, the proportion of the total of the aforementioned constituent units (B-1) and (B-2) is preferably 40 to 95 mol %, more preferably 50 to 95 mol %, and 55 to 95 mol %. The molar % is even better, and it is 60 to 90 molar %.

The constitutional unit B in the present invention includes a constitutional unit (B-3) selected from a compound derived from the following formula (b-3), a constitutional unit (B-4) derived from the following formula (b-4), and At least one kind of structural unit (hereinafter, this structural unit may be referred to as "constitutive unit B'") from the group consisting of the structural unit (B-5) of the compound represented by the following formula (b-5). When the structural unit B includes the structural unit B', a thin film having an excellent balance between low retardation and stretchability can be obtained.

[hua 6]

The compound represented by the above formula (b-3) is 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. The compound represented by the above formula (b-4) is 5-amino-1,3,3-trimethyl-1-(4-aminophenyl)indene. The compound represented by the above formula (b-5) is 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (alias: 2,2'-bis(trifluoromethyl)biphenyl) aniline). The above-mentioned structural unit B' may include all of the above-mentioned structural units (B-3) to (B-5), but includes a structure selected from the above-mentioned structural unit (B-3), the above-mentioned structural unit (B-4), and the above-mentioned structure. One or two kinds of constituent units in the group constituted by the unit (B-5) are preferable, and it is more preferable to include one kind of constituent units.

The proportion of the total of the aforementioned constituent unit (B-3), the aforementioned constituent unit (B-4) and the aforementioned constituent unit (B-5) in the constituent unit B is preferably 5 to 60 mol %, and 10 to 50 mol %. The molar % is more preferably, 10-45 mol %, still more preferably, 10-40 mol %. When the aforementioned constituent unit (B-3) is included as the constituent unit B', the ratio of the aforementioned constituent unit (B-3) relative to the constituent unit B is preferably 10 to 60 mol %, more preferably 25 to 55 mol %, 35-50 mol % is still more preferable, and 40-50 mol % is still more preferable. When including the aforementioned constituent unit (B-4) as the constituent unit B', the ratio of the aforementioned constituent unit (B-4) to the constituent unit B is preferably 10-60 mol %, more preferably 20-55 mol %, 30-50 mol % is still more preferable, and 35-50 mol % is still more preferable. When the aforementioned constituent unit (B-5) is included as the constituent unit B', the ratio of the aforementioned constituent unit (B-5) relative to the constituent unit B is preferably 5 to 40 mol %, more preferably 5 to 30 mol %, 5-20 mol % is still better, and 5-15 mol % is still better.

The polyimide of the present invention may include, in the structural unit B, structural units derived from diamines other than the compounds represented by the formulae (b-1) to (b-5) within the range that does not impair the effects of the present invention. , but not ideal. The ratio of constituent units derived from diamines other than the compounds represented by the above formulae (b-1) to (b-5) relative to constituent unit B is preferably 10 mol % or less, more preferably 5 mol % or less, and 1 Molar % or less is still better, and 0 molar % is still better.

[Production method of polyimide] The polyimide of the present invention is obtained by reacting a diamine component and a tetracarboxylic acid component.

As a tetracarboxylic acid component, a tetracarboxylic acid or its derivative(s) can be mentioned. A tetracarboxylic-acid component can be used individually or in combination of 2 or more types. As a derivative of a tetracarboxylic acid, the anhydride or alkyl ester of the said tetracarboxylic acid is mentioned. As for the alkyl ester of a tetracarboxylic acid, it is preferable that the carbon number of an alkyl group is 1-3, For example, the dimethyl ester of a tetracarboxylic acid, a diethyl ester, and a dipropyl ester are mentioned. Among the tetracarboxylic acid components used in the present invention, 1,2,4,5-cyclohexanetetracarboxylic acid or a derivative thereof is essential, and among them, 1,2,4,5-cyclohexanetetracarboxylic acid is preferably contained Dianhydride [above formula (a-1)].

Relative to all the tetracarboxylic acid components, the usage amount of 1,2,4,5-cyclohexanetetracarboxylic acid or its derivatives is preferably 70~100 mol%, more preferably 85~100 mol%, 99% ~100 mol% is still better, and 100 mol% is even better.

In addition, tetracarboxylic acid components other than 1,2,4,5-cyclohexanetetracarboxylic acid or a derivative thereof may be contained. The tetracarboxylic acid component includes at least one selected from the group consisting of an aromatic ring-containing tetracarboxylic acid or a derivative thereof, and an alicyclic hydrocarbon structure-containing tetracarboxylic acid or a derivative thereof. kind. The tetracarboxylic acid component may be used alone or in combination of two or more. Examples of aromatic ring-containing tetracarboxylic acids include pyromellitic acid, 3,3',4,4'-diphenyltetracarboxylic acid, and 3,3',4,4'-benzophenone Tetracarboxylic acid, 4,4'-oxydiphthalic acid, 4,4'-(hexafluoroisopropylidene)diphthalic acid, 2,2',3,3'-benzophenone tetra Carboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 2,2',3,3'-biphenyltetracarboxylic acid , 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 2,2-bis(3,4-dicarboxyphenoxy) Phenyl)propane, 1,1-bis(2,3-dicarboxyphenyl)ethane, 1,2-bis(2,3-dicarboxyphenyl)ethane, 1,1-bis(3,4 -Dicarboxyphenyl)ethane, 1,2-bis(3,4-dicarboxyphenyl)ethane, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl) ) methane, 4,4'-(p-phenylenedioxy)diphthalic acid, 4,4'-(m-phenylenedioxy)diphthalic acid, 2,3,6,7 - Naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid and their derivatives.

As the tetracarboxylic acid containing an alicyclic hydrocarbon structure, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,4,5-cyclopentanetetracarboxylic acid, bicyclo[2.2 .2] Oct-7-ene-2,3,5,6-tetracarboxylic acid, dicyclohexyltetracarboxylic acid, cyclopentanone bisspironorbornane tetracarboxylic acid or their positional isomers, and their derivative. As a tetracarboxylic acid component which does not contain an alicyclic hydrocarbon structure and does not contain an aromatic ring, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid can be mentioned. acid, etc. or their derivatives.

The amount of tetracarboxylic acid components other than 1,2,4,5-cyclohexanetetracarboxylic acid or its derivatives is preferably 30 mol % or less, more preferably 15 mol % or less, relative to all tetracarboxylic acid components. Preferably, it is 1 mol % or less, even more preferably, it is 0 mol %.

The diamine component used in the present invention is not limited to the diamine that provides the structural unit B, and may be a diisocyanate corresponding to the diamine, but a diamine is preferable. The diamine component used in the present invention includes the compound represented by the above formula (b-1) and the compound represented by the above formula (b-2), and further includes a compound selected from the group consisting of the compound represented by the above formula (b-3), the above formula At least one of the compound represented by (b-4) and the compound represented by the above formula (b-5) is preferable. In addition, 5-amino-1,3,3-trimethyl-1-(4-aminophenyl)indene (hereinafter sometimes referred to as "5-aminophenyl") represented by the above formula (b-4) Isomer") is sometimes mixed with 6-amino-1,3,3-trimethyl-1-(4-aminophenyl)indene (hereinafter sometimes referred to as " 6-amino isomer"). That is, when the compound represented by the said formula (b-4) is used as a diamine component, a 5-amino isomer and a 6-amino isomer may be mixed.

Relative to all the diamine components, the usage amount of the compound represented by the above formula (b-1) is less than 50 mol %, preferably 5-45 mol %, more preferably 10-45 mol %, 15-45 mol %. The molar % is even better, and it is even more preferably 20-40 molar %. Relative to all the diamine components, the usage amount of the compound represented by the above formula (b-2) is 15 mol % or more, preferably 15-70 mol %, more preferably 15-60 mol %, 20-50 mol %. The molar % is still better, 30-50 mol % is still better, 35-50 mol % is still better, 40-50 mol % is still better. The total usage amount of the compound represented by the above formula (b-1) and the compound represented by the above formula (b-2) is 40 mol % or more, preferably 40 to 95 mol %, and 50 mol % relative to all the diamine components. It is more preferably ~95 mol%, still more preferably 55~95 mol%, still more preferably 60~90 mol%. The total amount of the compound represented by the above formula (b-3), the compound represented by the above formula (b-4), and the compound represented by the above formula (b-5) is preferably 5 to 60 mol with respect to all the diamine components. %, preferably 10-55 mol%, still more preferably 10-50 mol%, still more preferably 10-45 mol%, still more preferably 10-40 mol%. Relative to all the diamine components, the usage amount of the compound represented by the above formula (b-3) is preferably 10-60 mol %, preferably 25-55 mol %, more preferably 35-50 mol %, 40~50 mol% is better. Relative to all diamine components, the usage amount of the compound represented by the above formula (b-4) is preferably 10-60 mol %, preferably 20-55 mol %, more preferably 30-50 mol %, 35~50 mol% is better. With respect to all the diamine components, the usage amount of the compound represented by the above formula (b-5) is preferably 5-40 mol %, preferably 5-30 mol %, more preferably 5-20 mol %, 5~15 mol% is better.

The diamine component may contain diamine components other than the compounds represented by the above formulae (b-1) to (b-5). As this diamine component, at least 1 sort(s) chosen from the group which consists of an aromatic diamine and an aliphatic diamine can be mentioned. This diamine component can be used individually or in combination of 2 or more types. In addition, "aromatic diamine" refers to a diamine in which an amine group is directly bonded to an aromatic ring, and a part of its structure may contain an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, other substituents (for example, a halogen atom, a sulfonic acid group) acyl group, carbonyl group, oxygen atom, etc.). "Aliphatic diamine" refers to a diamine in which the amine group is directly bonded to an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and a part of its structure may also contain an aromatic hydrocarbon group, other substituents (for example: halogen atom, sulfonyl group) , carbonyl group, oxygen atom, etc.).

Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, benzidine, o-tolidine, m-phenylenediamine Toluidine, Octafluorobenzidine, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3, 3'-Dichloro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,6-diaminonaphthalene, 1,5-diaminobiphenyl Aminonaphthalene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl bismuth, 3,4'-diaminodiphenylene, 4,4'-diaminobenzophenone, 2,2-bis[4-(2-methyl-4-aminophenoxy)benzene yl]propane, 2,2-bis[4-(2,6-dimethyl-4-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-methyl-4- Aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(2,6-dimethyl-4-aminophenoxy)phenyl]hexafluoropropane, 4,4'- Bis(4-aminophenoxy)biphenyl, 4,4'-bis(2-methyl-4-aminophenoxy)biphenyl, 4,4'-bis(2,6-dimethyl -4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]diphenyl, bis[ 4-(2-Methyl-4-aminophenoxy)phenyl]sine, bis[4-(2,6-dimethyl-4-aminophenoxy)phenyl]sine, bis[4 -(4-Aminophenoxy)phenyl]ether, bis[4-(2-methyl-4-aminophenoxy)phenyl]ether, bis[4-(2,6-dimethyl -4-Aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenoxy)benzene, 1,4-bis(2-methyl-4-aminophenoxy)benzene , 1,4-bis(2,6-dimethyl-4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(2-methyl) Alkyl-4-aminophenoxy)benzene, 1,3-bis(2,6-dimethyl-4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene -Dimethylbenzyl)benzene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(2-methyl-4-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane 3-Methyl-4-aminophenyl)propane, 2,2-bis(3-ethyl-4-aminophenyl)propane, 2,2-bis(3,5-dimethyl-4- Aminophenyl)propane, 2,2-bis(2,6-dimethyl-4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2 -Bis(2-methyl-4-aminophenyl)hexafluoropropane, 2,2-bis(2,6-dimethyl-4-aminophenyl)hexafluoropropane, α,α'-bis (4-Aminophenyl)-1,4-diisopropylbenzene, α,α'-bis(2-methyl-4-aminophenyl)-1,4-diisopropylbenzene, α ,α'-bis(2,6-dimethyl-4-aminophenyl)-1,4- Diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene, α,α'-bis(4-aminophenyl)-1,3- Diisopropylbenzene, α,α'-bis(2-methyl-4-aminophenyl)-1,3-diisopropylbenzene, α,α'-bis(2,6-dimethylbenzene) -4-Aminophenyl)-1,3-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,3-diisopropylbenzene, 9,9-bis( 2-Methyl-4-aminophenyl) fluoride, 9,9-bis(2,6-dimethyl-4-aminophenyl) fluoride, 1,1-bis(4-aminophenyl) Cyclopentane, 1,1-bis(2-methyl-4-aminophenyl)cyclopentane, 1,1-bis(2,6-dimethyl-4-aminophenyl)cyclopentane , 1,1-bis(4-aminophenyl)cyclohexane, 1,1-bis(2-methyl-4-aminophenyl)cyclohexane, 1,1-bis(2,6- Dimethyl-4-aminophenyl)cyclohexane, 1,1-bis(4-aminophenyl)-4-methyl-cyclohexane, 1,1-bis(4-aminophenyl) ) norbornane, 1,1-bis(2-methyl-4-aminophenyl)norbornane, 1,1-bis(2,6-dimethyl-4-aminophenyl)norbornane Alkane, 1,1-bis(4-aminophenyl)adamantane, 1,1-bis(2-methyl-4-aminophenyl)adamantane, 1,1-bis(2,6-bis Methyl-4-aminophenyl)adamantane, etc.

These can be used individually or in combination of 2 or more types.

Aliphatic diamines include, for example, ethylenediamine, hexamethylenediamine, polyethylene glycol bis(3-aminopropyl) ether, and polypropylene glycol bis(3-aminopropyl) ether , 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, m-xylylenediamine, p-xylylenediamine, 1,4-bis(2 -Amino-isopropyl)benzene, 1,3-bis(2-amino-isopropyl)benzene, isophoronediamine, norbornanediamine, siloxanediamine, 4,4' -Diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminobicyclo Hexylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodicyclohexylmethane, 2,3-bis(aminomethyl)-bicyclo[2.2.1]heptane , 2,5-bis(aminomethyl)-bicyclo[2.2.1]heptane, 2,6-bis(aminomethyl)-bicyclo[2.2.1]heptane, 2,2-bis(4 , 4'-diaminocyclohexyl) propane, 2,2-bis(4,4'-diaminomethylcyclohexyl) propane, etc.

The use amount of diamine components other than the compounds represented by the above formulas (b-1) to (b-5) is preferably 10 mol % or less, more preferably 5 mol % or less, 1 Molar % or less is still better, and 0 molar % is still better.

When producing the polyimide of the present invention, in terms of the feed ratio of the tetracarboxylic acid component and the diamine component, the diamine component is preferably 0.9 to 1.1 mol relative to 1 mol of the tetracarboxylic acid component.

When producing the polyimide of the present invention, the above-mentioned tetracarboxylic acid component and the above-mentioned diamine component are used, and a blocking agent may be used in addition to these. As the end-capping agent, monoamines or dicarboxylic acids are suitable. With respect to 1 mol of the tetracarboxylic acid component, the feed amount of the added end-capping agent is preferably 0.0001-0.1 mol, more preferably 0.001-0.06 mol. For monoamine end-capping agents, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine are suggested. , 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc. Among them, benzylamine and aniline can be preferably used. The dicarboxylic acid-based end-capping agent is preferably a dicarboxylic acid, and a part thereof may be ring-closed. Suggested for example: phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenonedicarboxylic acid, 3,4-benzophenone Dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and the like. Among them, phthalic acid and phthalic anhydride can be preferably used.

The method of making the said tetracarboxylic-acid component and a diamine component react is not specifically limited, A well-known method can be used. In terms of a specific reaction method, (1) the tetracarboxylic acid component, the diamine component, and the reaction solvent are fed into the reactor, stirred at room temperature to 80° C. for 0.5 to 30 hours, and then heated to implement The method of imidization reaction; (2) after feeding the diamine component and the reaction solvent into the reactor and making it dissolved, then feeding the tetracarboxylic acid component, and stirring at room temperature to 80 ° C for 0.5 to 30 minutes as required. (3) the tetracarboxylic acid component, the diamine component, and the reaction solvent are fed into the reactor, and the temperature is raised immediately to implement the method of the imidization reaction, etc. .

The reaction solvent used for the production of polyimide may be one that can dissolve the produced polyimide without inhibiting the imidization reaction. For example, an aprotic solvent, a phenol type solvent, an ether type solvent, a carbonate type solvent, etc. are mentioned.

Specific examples of the aprotic solvent include N,N-dimethylisobutylamide, N,N-dimethylformamide, N,N-dimethylacetamide, N- Amide-based solvents such as methyl-2-pyrrolidone, N-methylcaprolactone, 1,3-dimethylimidazolidinone, tetramethylurea; γ-butyrolactone, γ-valerolactone Isolactone-based solvents; phosphorus-containing amide-based solvents such as hexamethylphosphine, hexamethylphosphine triamide, etc.; sulfur-containing solvents such as dimethyl sulfoxide, dimethyl sulfoxide, and cyclobutane; , ketone-based solvents such as cyclohexanone and methylcyclohexanone; amine-based solvents such as picoline and pyridine; ester-based solvents such as acetic acid-2-methoxy-1-methylethyl ester, etc.

Specific examples of the phenol-based solvent include phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol Methylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, etc. Specific examples of the ether-based solvent include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, and 1,2-bis(2-methoxyethoxy) ) ethane, bis[2-(2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, etc. Moreover, as a specific example of a carbonate type solvent, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, etc. are mentioned. Among the above-mentioned reaction solvents, an aprotic solvent is preferable, an amide-based solvent or a lactone-based solvent is more preferable, and γ-butyrolactone is even more preferable. Moreover, the said reaction solvent can be used individually or in mixture of 2 or more types.

In the imidization reaction, a Dean-Stark apparatus or the like is preferably used, and the reaction is carried out while removing water generated during production. By carrying out such an operation, the degree of polymerization and the imidization rate can be further increased.

A known imidization catalyst can be used for the above imidization reaction. As the imidization catalyst, an alkali catalyst or an acid catalyst can be mentioned. Examples of the base catalyst include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, and trimetidine Amine, triethylamine, tripropylamine, tributylamine, imidazole, N,N-dimethylaniline, N,N-diethylaniline and other organic base catalysts; potassium hydroxide, sodium hydroxide, potassium carbonate, carbonic acid Inorganic alkali catalysts such as sodium, potassium bicarbonate and sodium bicarbonate. Moreover, as acid catalysts, crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, toluic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, etc. The above-mentioned imidization catalysts may be used alone or in combination of two or more. Among the above, from the viewpoint of operability, an alkali catalyst is preferable, an organic alkali catalyst is more preferable, and triethylamine is even more preferable.

When using the above-mentioned catalyst, the temperature of the imidization reaction is preferably 120 to 250°C, more preferably 160 to 190°C, and even more preferably 180 to 190°C in consideration of the reaction rate and the inhibition of gelation. In addition, the reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water. In addition, the temperature of the imidization reaction when a catalyst is not used is preferably 200 to 350°C.

[Polyimide] From the viewpoint of the mechanical strength of the obtained polyimide film, the weight average molecular weight of the polyimide of the present invention is preferably 500 to 1,000,000. In addition, the weight average molecular weight of polyimide can be measured by gel filtration chromatography or the like. As a measurement example of a weight average molecular weight, the method of using N,N- dimethylformamide as a developing solvent and measuring the absolute molecular weight with a light scattering detector is mentioned.

The polyimide of the present invention may be further mixed with various additives within a range that does not impair the effects of the present invention. Examples of additives include antioxidants, photostabilizers, surfactants, flame retardants, plasticizers, inorganic fillers, and polymer compounds other than the aforementioned polyimide. The polymer compound includes polyimide other than the polyimide of the present invention, polycarbonate, polystyrene, polyimide, polyimide, and polyethylene terephthalate. Such as polyester, polyether dust, polycarboxylic acid, polyacetal, polyphenylene ether, poly dust, polybutene, polypropylene, polypropylene amide, polyvinyl chloride, etc.

[Polyimide Varnish] The polyimide varnish of the present invention is obtained by dissolving the polyimide of the present invention in an organic solvent. That is, the polyimide varnish of the present invention is a solution containing the polyimide of the present invention, which contains the polyimide of the present invention and an organic solvent, and the polyimide is dissolved in the organic solvent. The organic solvent is not particularly limited as long as it can dissolve the polyimide, and it is preferable to use singly or in combination of two or more of the above-mentioned compounds exemplified as the reaction solvent used for the production of the polyimide. The polyimide of the present invention has solvent solubility, so it can be made into a stable high-concentration varnish at room temperature.

The above-mentioned polyimide varnish may be a polyimide-containing solution itself obtained by dissolving a polyimide obtained by a polymerization method in a reaction solvent. Moreover, at least 1 sort(s) chosen from the solvent exemplified above as a solvent for dissolving polyimide may be mixed with the said polyimide containing solution.

The solid content concentration of the solution containing the polyimide of the present invention (the polyimide varnish of the present invention) can be appropriately selected according to the workability and the like when forming a polyimide film, which will be described later, and the polyimide of the present invention can be produced. The reaction solvent used for imide is evaporated and concentrated, or the solid content concentration and viscosity are adjusted by adding an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the polyimide of the present invention. The solid content concentration of the solution containing the polyimide of the present invention (polyimide varnish of the present invention) is preferably 5 to 60 mass %, more preferably 10 to 45 mass %. The solution viscosity of the polyimide of the present invention is preferably 1~200Pa･s, more preferably 5~150Pa･s. The solution viscosity of polyimide is a value measured at 23°C using an E-type viscometer.

[Polyimide film] The polyimide film of the present invention is characterized in that it contains the polyimide of the present invention, and has low phase retardation and excellent stretchability. The polyimide film of the present invention is preferably composed of the polyimide of the present invention. The method for producing the polyimide film of the present invention is not particularly limited, and a known method can be used. For example, the solution containing the polyimide of the present invention (polyimide varnish of the present invention), or the solution containing the polyimide of the present invention and the above-mentioned various additives are coated on a glass plate, A method of removing solvent components such as organic solvents contained in the solution on a smooth support such as a metal plate or plastic, or after forming it into a thin film.

The solution containing the above-mentioned polyimide may be a polyimide solution itself obtained by dissolving the polyimide obtained by the polymerization method in the reaction solvent. Moreover, at least 1 sort(s) chosen from the solvent exemplified above as a solvent for dissolving polyimide may be mixed in the said polyimide solution. The thickness of the polyimide film of the present invention can be easily controlled by adjusting the solid content concentration and viscosity of the polyimide-containing solution as described above.

A mold release agent may also be coated on the surface of the aforementioned support as required. The following method is suitable for the method of heating and evaporating a solvent component after coating the said support body with the solution containing the said polyimide. That is, after evaporating the solvent at a temperature of 120°C or less to form a self-supporting film, peel the self-supporting film from the support, fix the end of the self-supporting film, and place it on the used film. A polyimide film is produced by drying at a temperature higher than or equal to the boiling point of the solvent component and not higher than 350°C. In addition, drying is preferably performed in a nitrogen atmosphere. The pressure of the drying atmosphere gas may be any of reduced pressure, normal pressure, and increased pressure.

The thickness of the polyimide film of the present invention can be appropriately selected according to the application, etc., but is preferably 1-250 μm, more preferably 5-100 μm, and even more preferably 10-90 μm. If the thickness is 1 to 250 μm, the practical application of making a self-supporting film is possible.

In the present invention, a polyimide film with a total light transmittance of preferably 85% or more, more preferably 88% or more, and even more preferably 89% or more at a thickness of 80 μm can be prepared. In the present invention, a polyimide film having a yellowness index (YI value) of preferably 2.7 or less, more preferably 2.5 or less, and even more preferably 2.2 or less can be prepared. In the present invention, a polyimide film having a glass transition temperature of preferably 220°C or higher, more preferably 250°C or higher, and still more preferably 280°C or higher can be prepared. Specifically, the total light transmittance, YI value, and glass transition temperature of the polyimide film can be measured by the methods described in the examples.

In the present invention, the retardation value (Rth) in the thickness direction is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 120 nm or less, and still more preferably 90 nm or less. In addition, in this specification, "low retardation" means that the retardation value (Rth) in the thickness direction is low, and the retardation value (Rth) in the thickness direction preferably falls within the aforementioned range. In the present invention, a polyimide film having a birefringence of preferably 0.003 or less, more preferably 0.0025 or less, still more preferably 0.002 or less, and still more preferably 0.0012 or less can be prepared. In the present invention, the tensile elongation at break (measurement temperature of 23° C., humidity of 50% RH) is preferably 8% or more, more preferably 8.2% or more, still more preferably 8.5% or more, and still more preferably 9%. % or more of polyimide film. Specifically, the retardation value (Rth), birefringence, and tensile elongation at break of the polyimide film in the thickness direction can be measured by the methods described in Examples.

The polyimide film containing the polyimide of the present invention can be suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, and optical members. [Example]

The present invention will be specifically described below based on examples. However, the present invention is not limited by these examples. The physical properties of the polyimide solutions and polyimide films obtained in the following Examples and Comparative Examples were measured by the methods shown below. (1) Solid content concentration: The determination of the solid content concentration of the polyimide solution (polyimide varnish) is performed by heating the sample in a small electric furnace MMF-1 manufactured by AS ONE Co., Ltd. at 300°C × 30min. The sample weight difference is calculated. (2) Film thickness: The film thickness was measured using a micrometer manufactured by Mitutoyo Co., Ltd.

(3) Total light transmittance, YI value The measurement was carried out in accordance with JIS K7361-1:1997, using a color-turbidity simultaneous measuring device "COH400" manufactured by Nippon Denshoku Kogyo Co., Ltd. (4) Glass transition temperature The measurement was performed using a differential scanning calorimeter device (DSC6200) manufactured by SII NanoTechnology Co., Ltd., and the glass transition temperature was obtained by performing DSC measurement on the condition of a temperature increase rate of 10° C./min.

(5) Birefringence, Rth The values of nx, ny, and nz at a measurement wavelength of 590 nm were measured using an ellipsometer "M-220" manufactured by JASCO Corporation. This value was used to obtain the retardation value (Rth) in the thickness direction defined by the following formula, and then divided by the thickness of the film to obtain the birefringence (Δn). Rth=[(nx＋ny)/2-nz]×d Δn=(nx+ny)/2-nz [In the formula, nx represents the largest refractive index among the in-plane refractive indices of the polyimide film; ny represents the smallest refractive index; nz represents the refractive index in the thickness direction; d represents the thickness (nm) of the film. ]

(6) Extensibility The measurement is based on ASTM-882-88, using a tensile testing machine "STROGRAPH VC-1" manufactured by Toyo Seiki Co., Ltd. to measure a temperature of 23°C, a humidity of 50% RH, a distance between jigs of 50mm, and a tensile speed of 50mm/min. The tensile test was carried out under the same conditions, and the tensile elongation at break was obtained. The higher the tensile elongation at break, the better the stretchability of the film.

<Example 1> As a diamine component, 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) 9.76 g (0.028 mol), 2,2-bis[4-(4-aminophenyl) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Industry Co., Ltd.) 8.62 g (0.021 mol), and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (manufactured by Wakayama Seika Industry Co., Ltd.) 6.72 g (0.021 mol), and 46.86 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) were put into a stainless steel half-moon-shaped stirring blade, a nitrogen gas introduction pipe, and a The Dean-Stark apparatus of the cooling tube, the thermometer, and the 300 mL 5-neck round-bottomed flask with the glass end cap were stirred to obtain a solution at a temperature of 70° C. in the system, under a nitrogen atmosphere, and a rotation speed of 200 rpm. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 11.72 g was added to the solution at one time, then 3.54 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a mantle heater for a period of time. The temperature in the reaction system was raised to 190°C in about 20 minutes. Collect the distillate components, adjust the rotation speed according to the viscosity increase, and keep the temperature in the reaction system at 190°C and reflux for 5 hours. After that, 97.62 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for about 3 hours to homogenize, to obtain a polymer with a solid content concentration of 20% by mass. Imide solution. Then, the obtained polyimide solution was coated on a glass plate, and the solvent was volatilized by maintaining the heating plate at 100° C. for 60 minutes, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame, and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 56 μm. The results are shown in Table 1.

<Example 2> As a diamine component, 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) 9.76 g (0.028 mol), 2,2-bis[4-(4-aminophenyl) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Industry Co., Ltd.) 14.37 g (0.035 mol), and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (manufactured by Wakayama Seika Industry Co., Ltd.) 2.24 g (0.007 mol), and 48.38 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) were put into a stainless steel half-moon-shaped stirring blade, a nitrogen gas introduction pipe, and a The Dean-Stark apparatus of the cooling tube, the thermometer, and the 300 mL 5-neck round-bottomed flask with the glass end cap were stirred to obtain a solution at a temperature of 70° C. in the system, under a nitrogen atmosphere, and a rotation speed of 200 rpm. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 12.09 g was added to the solution at one time, then 3.54 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a heating pack for about 20 minutes. The temperature in the reaction system was raised to 190°C. The distilled components were collected, and the rotational speed was adjusted in accordance with the increase in viscosity, while maintaining the temperature in the reaction system at 190° C. and refluxing for 5 hours. Then, 100.8 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for about 3 hours to homogenize, to obtain a polymer with a solid content concentration of 20% by mass. Imide solution. Then, the obtained polyimide solution was coated on a glass plate, and the solvent was volatilized by maintaining the heating plate at 100° C. for 60 minutes, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 89 μm. The results are shown in Table 1.

<Example 3> 7.32 g (0.021 moles) of 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) as a diamine component, 2,2-bis[4-(4-aminophenyl) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Industry Co., Ltd.) 5.75 g (0.014 moles), and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (manufactured by Wakayama Seika Industry Co., Ltd.) 18.15 g (0.035 mol), and 54.20 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) The Dean-Stark apparatus of the cooling tube, the thermometer, and the 300 mL 5-neck round-bottomed flask with the glass end cap were stirred to obtain a solution at a temperature of 70° C. in the system, under a nitrogen atmosphere, and a rotation speed of 200 rpm. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 13.55g was added to the solution at one time, then 3.54g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a heating pack, and the solution was heated for about 20 minutes. The temperature in the reaction system was raised to 190°C. Collect the distillate components, adjust the rotation speed according to the viscosity increase, and keep the temperature in the reaction system at 190°C and reflux for 5 hours. Then, 112.9 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for about 3 hours to homogenize, to obtain a polymer with a solid content concentration of 20% by mass. Imide solution. Then, the obtained polyimide solution was coated on a glass plate, and the solvent was volatilized by maintaining the heating plate at 100° C. for 60 minutes, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 62 μm. The results are shown in Table 1.

<Example 4> 4.88 g (0.014 moles) of 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) as a diamine component, 2,2-bis[4-(4-amino) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Industry Co., Ltd.) 11.49 g (0.028 mol), and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (manufactured by Wakayama Seika Industry Co., Ltd.) 14.52 g (0.028 mol), and 53.81 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) The Dean-Stark apparatus of the cooling tube, the thermometer, and the 300 mL 5-neck round-bottomed flask with the glass end cap were stirred to obtain a solution at a temperature of 70° C. in the system, under a nitrogen atmosphere, and a rotation speed of 200 rpm. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 13.45g was added to the solution at one time, and then 3.54g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a heating pack for about 20 minutes. The temperature in the reaction system was raised to 190°C. Collect the distillate components, adjust the rotation speed according to the viscosity increase, and keep the temperature in the reaction system at 190°C and reflux for 5 hours. After that, 112.1 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for about 3 hours to homogenize, and a polymer having a solid content concentration of 20% by mass was obtained. Imide solution. Then, the obtained polyimide solution was coated on a glass plate, and the solvent was volatilized by maintaining the heating plate at 100° C. for 60 minutes, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 74 μm. The results are shown in Table 1.

<Example 5> 4.88 g (0.014 moles) of 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) as a diamine component, 2,2-bis[4-(4-amino) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Industry Co., Ltd.) 11.49 g (0.028 mol), and 5(6)-amino-1,3,3-trimethyl-1-(4- Aminophenyl)dihydroindene (manufactured by Junyo Pharmaceutical Co., Ltd.) 7.46 g (0.028 mol) and γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) 45.34 g were put into a half-moon-shaped stirring blade made of stainless steel. , nitrogen introduction tube, Dean-Stark device equipped with cooling tube, thermometer, 300mL 5-neck round-bottom flask with glass end cap, and the temperature inside the system is 70°C, under nitrogen atmosphere, and the speed of rotation is 200rpm. Stir to obtain a solution. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 11.33 g was added to the solution at one time, then 3.54 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a heating pack for about 20 minutes. The temperature in the reaction system was raised to 190°C. Collect the distillate components, adjust the rotation speed according to the viscosity increase, and keep the temperature in the reaction system at 190°C and reflux for 5 hours. After that, 94.45 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for about 3 hours to homogenize, to obtain a polymer with a solid content concentration of 20% by mass. Imide solution. Then, the obtained polyimide solution was coated on a glass plate and kept at 100° C. for 60 minutes on a hot plate to volatilize the solvent, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 85 μm. The results are shown in Table 1.

<Comparative Example 1> As a diamine component, 9,9-bis(4-aminophenyl) fluoride (manufactured by Taoka Chemical Industry Co., Ltd.) 9.76 g (0.028 mol), 2,2-bis[4-(4-aminophenyl) Phenoxy)phenyl]propane (manufactured by Wakayama Seika Co., Ltd.) 2.87 g (0.007 moles), and 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (manufactured by Wakayama Seika Industry Co., Ltd.) 11.21 g (0.035 mol) and 45.35 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) were put into a stainless steel half-moon-shaped stirring blade, a nitrogen gas introduction pipe, and a The Dean-Stark apparatus of the cooling tube, the thermometer, and the 300 mL 5-neck round-bottomed flask with the glass end cap were stirred to obtain a solution at a temperature of 70° C. in the system, under a nitrogen atmosphere, and a rotation speed of 200 rpm. 16.47 g (0.07 moles) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and γ-butyrolactone (Mitsubishi Chemical Co., Ltd.) as tetracarboxylic acid components Co., Ltd.) 11.34 g was added to the solution at one time, then 3.54 g of triethylamine (manufactured by Kanto Chemical Co., Ltd.) was added as an imidization catalyst, and heated with a heating pack, and the solution was heated for about 20 minutes. The temperature in the reaction system was raised to 190°C. Collect the distillate components, adjust the rotation speed according to the viscosity increase, and keep the temperature in the reaction system at 190°C and reflux for 5 hours. After that, 94.47 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the temperature in the reaction system was cooled to 120° C., followed by stirring for further about 3 hours to homogenize to obtain a polymer with a solid content concentration of 20% by mass. Imide solution. Then, the obtained polyimide solution was coated on a glass plate, and the solvent was volatilized by maintaining the heating plate at 100° C. for 60 minutes, thereby obtaining a colorless and transparent primary drying film with self-supporting properties. The film was fixed on a stainless steel frame and heated in a hot air dryer at 250° C. for 2 hours to evaporate the solvent to obtain a film with a thickness of 69 μm. The results are shown in Table 1.

[Table 1]

Abbreviations in the table are detailed below. HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride [compound represented by formula (a-1)] BAFL: 9,9-bis(4-aminophenyl)pyrene [compound represented by formula (b-1) (R: hydrogen atom)] BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane [compound represented by formula (b-2)] HFBAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane [compound represented by formula (b-3)] TMDA: 5(6)-amino-1,3,3-trimethyl-1-(4-aminophenyl)indene [compound represented by formula (b-4)] TFMB: 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl [compound represented by formula (b-5)]

It can be seen from Table 1 that the polyimide films of Examples 1 to 5 are excellent in colorless transparency and heat resistance, as well as low phase retardation and elongation, so all the above-mentioned properties are well balanced. On the other hand, the polyimide film of Comparative Example 1 had a high retardation value (Rth) in the thickness direction and poor extensibility, so that a film with low retardation and excellent extensibility could not be obtained.

Claims (9)

A polyimide having a structural unit A derived from a tetracarboxylic acid or a derivative thereof and a structural unit B derived from a diamine, the structural unit A comprising a structural unit (A-1) derived from a compound represented by the following formula (a-1) ), the constitutional unit B comprises a constitutional unit (B-1) from a compound represented by the following formula (b-1) and a constitutional unit (B-2) from a compound represented by the following formula (b-2), and comprises a In the structural unit (B-3) derived from the compound represented by the following formula (b-3), the structural unit (B-4) derived from the compound represented by the following formula (b-4), and from the following formula (b-5) At least one of the constituent units (B-5) of the represented compound, the ratio of the constituent unit (B-1) to the constituent unit B is less than 50 mol %, and the constituent unit (B-2) relative to the constituent unit B The proportion of unit B is 15 mol% or more, and the total proportion of the constituent unit (B-1) and the constituent unit (B-2) in the constituent unit B is 40 mol% or more;

[hua 2]

In formula (b-1), R each independently represents a hydrogen atom, a fluorine atom or a methyl group. As in the polyimide of claim 1, the ratio of the structural unit (B-1) to the structural unit B is 5-45 mol %. As for the polyimide of claim 1 or 2, the ratio of the structural unit (B-2) to the structural unit B is 15-70 mol %. As for the polyimide of claim 1 or 2 of the scope of the application, wherein the total of the structural unit (B-3), the structural unit (B-4) and the structural unit (B-5) occupies the 10% of the structural unit B The proportion is 5~60 mol%. The polyimide of claim 4 of the scope of the application, wherein the ratio of the structural unit (B-3) to the structural unit B is 10-60 mol %. The polyimide of claim 4 of the scope of the application, wherein the ratio of the constituent unit (B-4) to the constituent unit B is 10-60 mol %. As for the polyimide of claim 4 of the claimed scope, the ratio of the constituent unit (B-5) to the constituent unit B is 5-40 mol %. A polyimide varnish is prepared by dissolving the polyimide according to any one of items 1 to 7 of the patent application scope in an organic solvent. A polyimide film, which contains the polyimide according to any one of items 1 to 7 of the patent application scope.