WO2018062428A1 - Acid dianhydride and use thereof - Google Patents

Abstract

[Problem] To provide a polyamic acid and a polyimide that yield a polyimide film characterized by having low retardation as well as exceptional flexibility and transparency, and a novel acid dianhydride to be used in the production of said polyamic acid and polyimide. [Solution] A polyamic acid obtained by reacting an acid dianhydride and a diamine component, wherein the polyamic acid is characterized in that the acid dianhydride component includes an acid dianhydride represented by formula (1-1); a polyimide that is an imidized product of said polyamic acid; a composition for forming a polyimide film that includes said polyamic acid; a composition for forming a film that includes said polyimide; and polyimide films obtained therefrom. (In the formula, R¹ to R⁵ each independently represent a halogen atom, an alkyl group, or an alkoxy group; R⁶ and R⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; a and b each independently represent an integer of 0-4; c and d each independently represent an integer of 0-9; and e represents an integer of 0-2.)

Description

Acid dianhydride and its use

The present invention relates to a novel acid dianhydride and its use for polyamic acid and polyimide.

In recent years, with rapid advances in electronics such as liquid crystal displays and organic electroluminescence displays, it has become necessary to make devices thinner and lighter, and more flexible.
In these devices, various electronic elements such as thin film transistors and transparent electrodes are formed on a glass substrate. By replacing this glass material with a flexible and lightweight resin material, the device itself can be made thinner or thinner. Light weight and flexibility are expected.
And as a candidate of such a resin material, polyimide attracts attention, and various reports regarding a polyimide film have been made conventionally (see, for example, Patent Documents 1 and 2).

JP-A-60-188427 JP 58-208322 A International Publication 2011/149018 Pamphlet

By the way, when a polyimide resin material is used as a display substrate, it is desirable that the resin material is not only excellent in transparency but also has a low retardation as one of the required performances.
That is, retardation (phase difference) is the product of birefringence (difference between two orthogonal refractive indexes) and film thickness, and this numerical value, particularly retardation in the thickness direction, is important because it affects viewing angle characteristics. It is a numerical value. A large retardation value may cause a decrease in display quality of the display (see, for example, Patent Document 3). Even in a flexible display substrate, these characteristics are required in addition to high flexibility (flexibility).

The present invention has been made in view of such circumstances, and is not only excellent in heat resistance, flexibility and transparency, but also polyamic acid and polyimide which give a polyimide film having the characteristics of low retardation, and It aims at providing the novel acid dianhydride used for manufacture of a polyamic acid and a polyimide.

As a result of intensive investigations to solve the above problems, the inventors of the present invention converted an acid dianhydride compound represented by the following formula (1-1) into an alicyclic tetrahydrate such as tetracyclobutanoic acid dianhydride. Copolymerization with an aromatic diamine such as 2,2′-di (trifluoromethyl) benzidine together with a carboxylic dianhydride to obtain a polyamic acid and a polyimide exhibiting good solubility in an organic solvent, and From the composition (solution) obtained by dissolving the polyamic acid and polyimide in an organic solvent, a polyimide film having not only excellent heat resistance, flexibility and transparency, but also low retardation can be obtained. The headline and the present invention were completed.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁵は、互いに独立して、ハロゲン原子、炭素原子数１乃至５のアルキル基または炭素原子数１乃至５のアルコキシ基を表し、
Ｒ⁶及びＲ⁷は、互いに独立して、水素原子、ハロゲン原子、炭素原子数１乃至５のアルキル基又は炭素原子数１乃至５のアルコキシ基を表し、
ａおよびｂは、互いに独立して、０～４の整数を表し、
ｃおよびｄは、互いに独立して、０～９の整数を表し、
ｅは、０～２の整数を表す。）
　第２観点として、前記ジアミン成分が式（Ａ１）で表されるジアミンを含むことを特徴とする、第１観点に記載のポリアミック酸に関する。

（式中、Ｂ²は、式（Ｙ－１）～式（Ｙ－３４）からなる群から選ばれるいずれかの基を表す。）

（式中、＊は結合手を表す。）
　第３観点として、前記酸二無水物成分が、更に式（Ｃ１）で表されるテトラカルボン酸二無水物を含むことを特徴とする、第１観点又は第２観点に記載のポリアミック酸に関する。

〔式中、Ｂ¹は、式（Ｘ－１）～式（Ｘ－１２）からなる群から選ばれるいずれかの基を表す。

（式中、複数のＲは、互いに独立して、水素原子またはメチル基を表し、＊は結合手を表す。）〕
　第４観点として、第１観点乃至第３観点のうちいずれか一項に記載のポリアミック酸と、有機溶媒とを含むポリイミド膜形成用組成物に関する。
　第５観点として、第４観点に記載のポリイミド膜形成用組成物を用いて形成されるポリイミド膜に関する。
　第６観点として、第５観点に記載のポリイミド膜からなるフレキシブルデバイス用基板に関する。
　第７観点として、第１観点乃至第３観点のうちいずれか一項に記載のポリアミック酸をイミド化して得られるポリイミドに関する。
　第８観点として、第７観点に記載のポリイミドと、有機溶媒とを含む膜形成用組成物に関する。
　第９観点として、第８観点に記載の膜形成用組成物を用いて形成されるポリイミド膜に関する。
　第１０観点として、第９観点に記載のポリイミド膜からなるフレキシブルデバイス用基板に関する。
　第１１観点として、式（１－１）で表されることを特徴とする酸二無水物に関する。

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁵は、互いに独立して、ハロゲン原子、炭素原子数１乃至５のアルキル基または炭素原子数１乃至５のアルコキシ基を表し、
Ｒ⁶及びＲ⁷は、互いに独立して、水素原子、ハロゲン原子、炭素原子数１乃至５のアルキル基又は炭素原子数１乃至５のアルコキシ基を表し、
ａおよびｂは、互いに独立して、０～４の整数を表し、
ｃおよびｄは、互いに独立して、０～９の整数を表し、
ｅは、０～２の整数を表す。）
　第１２観点として、式（１－２）で表されることを特徴とする、第１１観点に記載の酸二無水物に関する。

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄおよびｅは、前記と同じ意味を示す。）
　第１３観点として、式（１－３）で表されることを特徴とする、第１２観点に記載の酸二無水物に関する。

　第１４観点として、式（２－１）で表されることを特徴とするテトラカルボン酸に関する。

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁵は、互いに独立して、ハロゲン原子、炭素原子数１乃至５のアルキル基または炭素原子数１乃至５のアルコキシ基を表し、
Ｒ⁶及びＲ⁷は、互いに独立して、水素原子、ハロゲン原子、炭素原子数１乃至５のアルキル基又は炭素原子数１乃至５のアルコキシ基を表し、
ａおよびｂは、互いに独立して、０～４の整数を表し、
ｃおよびｄは、互いに独立して、０～９の整数を表し、
ｅは、０～２の整数を表す。）
　第１５観点として、式（２－２）で表されることを特徴とする、第１４観点に記載のテトラカルボン酸に関する。

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄおよびｅは、前記と同じ意味を示す。）
　第１６観点として、式（２－３）で表されることを特徴とする、第１５観点に記載のテトラカルボン酸に関する。

That is, the present invention provides, as a first aspect, a polyamic acid obtained by reacting an acid dianhydride component with a diamine component,
The polyamic acid is characterized in that the acid dianhydride component contains an acid dianhydride represented by the following formula (1-1).

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. )
As a 2nd viewpoint, the said diamine component contains the diamine represented by a formula (A1), It is related with the polyamic acid as described in a 1st viewpoint.

(Wherein B ² represents any group selected from the group consisting of formula (Y-1) to formula (Y-34)).

(In the formula, * represents a bond.)
As a third aspect, the acid dianhydride component further includes a tetracarboxylic dianhydride represented by the formula (C1), and relates to the polyamic acid according to the first aspect or the second aspect.

[Wherein B ¹ represents any group selected from the group consisting of formulas (X-1) to (X-12)).

(In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.)
As a 4th viewpoint, it is related with the composition for polyimide film formation containing the polyamic acid as described in any one of a 1st viewpoint thru | or a 3rd viewpoint, and an organic solvent.
As a 5th viewpoint, it is related with the polyimide film formed using the composition for polyimide film formation as described in a 4th viewpoint.
As a 6th viewpoint, it is related with the board | substrate for flexible devices which consists of a polyimide film as described in a 5th viewpoint.
As a seventh aspect, the present invention relates to a polyimide obtained by imidizing the polyamic acid according to any one of the first aspect to the third aspect.
As an eighth aspect, the present invention relates to a film-forming composition comprising the polyimide according to the seventh aspect and an organic solvent.
A ninth aspect relates to a polyimide film formed by using the film forming composition as described in the eighth aspect.
As a 10th viewpoint, it is related with the board | substrate for flexible devices which consists of a polyimide film as described in a 9th viewpoint.
As an eleventh aspect, the present invention relates to an acid dianhydride characterized by being represented by the formula (1-1).

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. )
The twelfth aspect relates to the acid dianhydride according to the eleventh aspect, which is represented by the formula (1-2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e have the same meaning as described above.)
The thirteenth aspect relates to the acid dianhydride according to the twelfth aspect, which is represented by the formula (1-3).

As a fourteenth aspect, the present invention relates to a tetracarboxylic acid characterized by being represented by the formula (2-1).

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. )
The fifteenth aspect relates to the tetracarboxylic acid described in the fourteenth aspect, which is represented by the formula (2-2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e have the same meaning as described above.)
As a sixteenth aspect, the present invention relates to the tetracarboxylic acid according to the fifteenth aspect, which is represented by the formula (2-3).

The polyamic acid and polyimide of the present invention exhibit good solubility in an organic solvent, and the polyamic acid and polyimide are excellent in heat resistance, flexibility and transparency, and have a polyimide film (resin thin film) that can realize low retardation. Can be formed.
Moreover, since the polyimide film of this invention shows high transparency (high light transmittance, low yellowness), heat resistance, and low retardation, it can be used suitably as a board | substrate of a flexible device, especially a flexible display.

Hereinafter, the present invention will be described in more detail.
The polyamic acid according to the present invention can be obtained by polycondensation reaction between an acid dianhydride component containing an acid dianhydride represented by the following formula (1-1) and a diamine component. The obtained polyamic acid can be converted into a corresponding polyimide by a dehydration ring-closing reaction using heat or a catalyst. Both the polyamic acid and the polyimide are the subject of the present invention. The polyamic acid of the present invention is a reaction product of an acid dianhydride component containing an acid dianhydride represented by the following formula (1-1) and a diamine component, and the polyimide of the present invention includes the polyamic acid. It is an imidized product of an acid.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴及びＲ⁵は、互いに独立して、ハロゲン原子、炭素原子数１乃至５のアルキル基または炭素原子数１乃至５のアルコキシ基を表し、
Ｒ⁶及びＲ⁷は、互いに独立して、水素原子、ハロゲン原子、炭素原子数１乃至５のアルキル基又は炭素原子数１乃至５のアルコキシ基を表し、
ａおよびｂは、互いに独立して、０～４の整数を表し、
ｃおよびｄは、互いに独立して、０～９の整数を表し、
ｅは、０～２の整数を表す。） As the acid dianhydride represented by the formula (1-1), an acid dianhydride represented by the formula (1-2) is particularly preferable, and among them, excellent heat resistance, flexibility and transparency, and low retardation. In view of obtaining a polyamic acid and a corresponding polyimide that give a polyimide film with good reproducibility, an acid dianhydride represented by the formula (1-3) is preferable.

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. )

Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, and n-pentyl group. , Isoamyl group, neopentyl group, tert-amyl group, sec-isoamyl group, cyclopentyl group and the like.
Examples of the alkoxy group having 1 to 5 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, and n-pentoxy group. , Isopentoxy group, neopentoxy group, tert-pentoxy group and the like.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄ及びｅは上記と同じ意味を表す。） In the acid dianhydrides represented by the above formulas (1-1) to (1-3) of the present invention, tetracarboxylic acids represented by the following formulas (2-1) to (2-3) are respectively used as dehydrating agents. Can be obtained by dehydration within the molecule.

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e represent the same meaning as described above.)

（上記反応式中、Ｘはハロゲン原子を表し、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄ及びｅは上記と同じ意味を表す。） Specifically, the acid dianhydride represented by the above formula (1-1) is 9,10- [1,2] benzenoanthracene-1 in an organic solvent as shown in the following scheme as an example. , 4-diol compound (hereinafter also referred to as benzenoanthracenediol compound) and cyclohexanetricarboxylic acid halogenated anhydride in the presence of a base or an acid absorbent [Reaction Formula 1]. After the reaction, the solvent is removed, and then the reaction mixture is purified using a known method such as recrystallization, distillation, silica gel column chromatography, etc. to obtain the target acid dianhydride.
The reaction product of [Reaction Formula 1] is hydrolyzed to produce an intermediate (9,10- [1,2] benzenoanthracene-1,4-diyl bis (cyclohexanetricarboxylate) compound) (Formula (2-1 It can also be obtained by obtaining [Compound 2] and dehydrating this intermediate in a molecule with a dehydrating agent [Reaction Formula 3].
The acid dianhydrides represented by the above formulas (1-1) to (1-3) and the cyclohexane tricarboxylic acid esters represented by the above formulas (2-1) to (2-3) (intermediates thereof) Tetracarboxylic acid compounds) are also objects of the present invention.

(In the above reaction formula, X represents a halogen atom, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e represent the same meaning as described above. .)

In the reaction of [Reaction Formula 1], the charging ratio of the benzenoanthracenediol compound and the cyclohexanetricarboxylic acid halogenated anhydride is 2 to 4 mol of cyclohexanetricarboxylic acid halogenated anhydride with respect to 1 mol of the benzenoanthracenediol compound. Is preferred.
Examples of the base include organic compounds such as trimethylamine, triethylamine, diisopropylamine, diisopropylethylamine, N-methylpiperidine, 2,2,6,6-tetramethyl-N-methylpiperidine, pyridine, 4-dimethylaminopyridine and N-methylmorpholine. Organic bases such as amines are preferably used. The amount of the base used is not particularly limited as long as it is 1 mol or more with respect to 1 mol of cyclohexanetricarboxylic acid halide anhydride, but is usually about 1 to 5 mol, preferably 1 to 3 mol. Degree.
In addition, an acid absorbent may be used to neutralize an acid such as hydrochloric acid by-produced in the reaction. Examples of the acid absorbent include epoxides such as propylene oxide. The amount of the acid absorbent used is not particularly limited as long as it is 2 mol or more with respect to 1 mol of the benzenoanthracenediol compound, but it is usually about 2 to 10 mol, preferably about 2 to 4 mol. is there.
The organic solvent is not particularly limited as long as it does not affect the reaction, but aromatic hydrocarbons such as benzene, toluene and xylene; N, N-dimethylformamide (hereinafter referred to as DMF), Amides such as N, N-dimethylacetamide (hereinafter referred to as DMAc) and N-methyl-2-pyrrolidone (hereinafter referred to as NMP); diethyl ether, tetrahydrofuran (hereinafter referred to as THF), 1,4-dioxane, 1, Use ethers such as 2-dimethoxyethane, cyclopentylmethyl ether and diethyl ether; ketones such as 2-butanone and 4-methyl-2-pentanone; nitriles such as acetonitrile and dimethyl sulfoxide (hereinafter referred to as DMSO) Can do. These solvents may be used alone or in combination of two or more. In addition, when the acid dianhydride (1-1), which is the target product, is directly purified and taken out in [Reaction Formula 1], if the solvent contains a large amount of water, hydrolysis of the ester occurs. It is preferable to use a dehydrated solvent or after dehydrating. In addition, when the target acid dianhydride (1-1) is taken out via [Reaction Formula 2] and [Reaction Formula 3], a dehydrated solvent may or may not be used.
The reaction temperature can be about 0 to 200 ° C., preferably 20 to 150 ° C.
After the reaction, the solvent is distilled off and the reaction product is purified to obtain the target acid dianhydride. This purification method is arbitrary, and may be appropriately selected from known methods such as recrystallization, distillation and silica gel column chromatography. Moreover, the organic solvent used at the time of refinement | purification will not be specifically limited if it is a solvent which does not react with a product at the time of refinement | purification, It is the same as that of the organic solvent used for the said reaction.
If purification after the reaction is difficult, the crude product is hydrolyzed [Reaction Formula 2], and tetracarboxylic acid is obtained, followed by dehydration cyclization with a dehydrating agent [Reaction Formula 3]. Certain acid dianhydrides can also be obtained.

On the other hand, the reaction of [Reaction Formula 2] is not particularly limited as long as the acid dianhydride represented by Formula (1-1) and water are mixed. For example, Formula (1) generated by [Reaction Formula 1] -1) is added with water, optionally an organic solvent, acid or alkali, and hydrolyzed by heating to reflux to obtain a cyclohexanetricarboxylic acid ester (tetracarboxylic acid compound) represented by the formula (2-1) You can also get
Water is usually used in an amount of 2 to 100 times, preferably 2 to 40 times, more preferably 2 to 6 times the weight of the acid dianhydride represented by the formula (1-1).
In the above reaction, an organic solvent may be added. The organic solvent is not particularly limited as long as it does not affect the reaction, but aromatic hydrocarbons such as benzene, toluene and xylene; N, N-dimethylformamide (hereinafter referred to as DMF), Amides such as N, N-dimethylacetamide (hereinafter referred to as DMAc) and N-methyl-2-pyrrolidone (hereinafter referred to as NMP); diethyl ether, tetrahydrofuran (hereinafter referred to as THF), 1,4-dioxane, 1, Ethers such as 2-dimethoxyethane, cyclopentylmethyl ether and diethyl ether; ketones such as acetone, ethyl acetate, 2-butanone and 4-methyl-2-pentanone; nitriles such as acetonitrile; and dimethyl sulfoxide (hereinafter DMSO) Can be used. These solvents may be used alone or in combination of two or more. In order to proceed the hydrolysis efficiently, a highly polar solvent is preferable, for example, DMF, DMAc, NMP, THF, 1,4-dioxane, diethyl ether, acetonitrile, acetone, ethyl acetate, and the like are preferable.
In the above reaction, an acid may be added. The acid is not particularly limited, and examples of the acid include heteropolyacids such as phosphomolybdic acid and phosphotungstic acid; organic acids such as trimethylborate and triphenylphosphine; inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid; formic acid And hydrocarbon acids such as acetic acid, propionic acid and p-toluenesulfonic acid; and halogenated hydrocarbon acids such as trifluoroacetic acid. Preferably, hydrochloric acid, sulfuric acid, acetic acid and p-toluenesulfonic acid are used.
The acid is generally used in an amount of 0 to 100 times mol, preferably 0.01 to 10 times mol, of the acid dianhydride represented by the formula (1-1).
In addition, this reaction may be hydrolyzed using an alkaline aqueous solution. The alkali is not particularly limited, and examples of the alkali include alkali metals such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate and lithium carbonate, magnesium hydroxide and calcium hydroxide. Alkaline earth metals are mentioned. Of these, sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferable.
The amount of alkali used is usually 0 to 100 times mol, preferably 0.01 to 10 times mol, of the acid dianhydride represented by the formula (1-1).
The reaction temperature is not particularly limited but is, for example, −90 to 200 ° C., preferably 50 to 130 ° C.
The reaction time is usually 0.1 to 200 hours, preferably 0.5 to 100 hours.

The reaction of [Reaction Formula 3] may be a known method and is not particularly limited. For example, cyclohexanetricarboxylic acid represented by Formula (2-1) obtained by [Reaction Formula 2] An acid dianhydride represented by the formula (1-1) can be obtained by mixing an ester (tetracarboxylic acid compound) and a dehydrating agent in a solvent.

The dehydrating agent is not particularly limited as long as the dehydrating agent can come into contact with the cyclohexane tricarboxylic acid ester (tetracarboxylic acid compound) represented by the formula (2-1). It should be carried out in the presence of a dehydrating agent such as an aliphatic carboxylic acid anhydride such as acetic acid, propionic anhydride, trifluoroacetic anhydride, 1,3-dicyclohexylcarbodiimide, 2-chloro-1,3-dimethylimidazolinium chloride. Can do. Further, a lower carboxylic acid anhydride having 1 to 3 carbon atoms is preferable, more preferably a lower carboxylic acid anhydride having 1 to 2 carbon atoms, and among them, it is easy to remove after dehydration and is economically advantageous. Particularly preferred is acetic anhydride.

The amount of the dehydrating agent to be used is not particularly limited, but is preferably 2 to 50 equivalents, particularly preferably 4 to 20 equivalents, relative to the cyclohexanetricarboxylic acid ester (tetracarboxylic acid compound) represented by the formula (2-1). is there. If it is 2 to 50 equivalents, the anhydride can be sufficiently obtained and the amount of the acid dianhydride represented by the formula (1-1) obtained does not increase too much, and the formula (1 The acid dianhydride represented by -1) can be precipitated.

In the above reaction, an organic solvent that does not directly participate in the reaction can be used. Examples thereof include hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as 1,2-dichloroethane and 1,2-dichloropropane, and 1,4-dioxane.

Note that it is not necessary to completely dissolve the cyclohexanetricarboxylic acid ester (tetracarboxylic acid compound) represented by the formula (2-1) and perform the anhydride reaction in a homogeneous system. May be.

The heating temperature in the reaction is preferably 30 to 200 ° C., more preferably 40 to 180 ° C. The higher the reaction temperature, the higher the reaction rate. For this reason, it is preferable to carry out at the reflux temperature of the solvent used.

The reaction time may be appropriately set according to conditions such as the type of dehydrating agent to be used, temperature, etc., but is preferably 0.5 to 20 hours.

By the above-mentioned anhydride reaction, a suspension in which the acid dianhydride represented by the formula (1-1) is suspended in the dehydrating agent used can be obtained. After the anhydride reaction, the resulting suspension can be filtered to recover the acid dianhydride powder represented by formula (1-1). Moreover, you may concentrate the said suspension as needed.
Moreover, you may wash | clean the said filtration thing with an organic solvent as needed. The washing solvent is not particularly limited as long as the solvent does not react with the anhydride and the solubility of the target anhydride is low. For example, toluene, hexane, heptane, acetonitrile, acetone, chloroform, ethyl acetate, dimethyl carbonate, etc. Or a mixed solvent thereof. Of these, ethyl acetate and dimethyl carbonate are preferred.
Further, the acid dianhydride represented by the formula (1-1) with high purity can be obtained by removing the dehydrating agent and the solvent by drying under reduced pressure or the like. Moreover, the acid dianhydride which is a target object can also be obtained by refine | purifying using well-known methods, such as recrystallization, distillation, and silica gel column chromatography if needed.

The acid dianhydride represented by the formula (2-1) obtained in the present invention is a novel compound not described in any literature, and as described above, it can be easily represented by the formula (1-1). It can be used for various applications such as production of acid dianhydrides.

（上記スキーム中、Ｒ¹、Ｒ²、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ及びｅは上記と同じ意味を表す。） The benzenoanthracene diol compound used in the present invention, for example, as shown in the following scheme as an example, is a Diels-Alder reaction of an anthracene compound and a 1,4-benzoquinone compound in an organic solvent according to a known method. 9,10- [1,2] benzenoanthracene-13,16 (9H, 10H) -dione compound obtained by treatment under heating conditions in acetic acid solvent in the presence of 47% hydrogen bromide. it can.

(In the above scheme, R ¹ , R ² , R ⁵ , R ⁶ , R ⁷ , a, b and e have the same meaning as described above.)

〔式中、Ｂ¹は、式（Ｘ－１）～（Ｘ－１２）からなる群から選ばれる４価の基を表す。

（式中、複数のＲは、互いに独立して、水素原子またはメチル基を表し、＊は結合手を表す。）〕 From the standpoint of obtaining a polyamic acid (and corresponding polyimide) that gives a polyimide film having not only excellent heat resistance, flexibility and transparency, but also low retardation characteristics, with good reproducibility (and corresponding) In addition to the acid dianhydride represented by the above formula (1-1), the acid dianhydride component used for the production of polyimide) is preferably an alicyclic tetracarboxylic dianhydride, more preferably the following formula An acid dianhydride represented by (C1) is included.

[Wherein B ¹ represents a tetravalent group selected from the group consisting of formulas (X-1) to (X-12).

(In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.)

Among the acid dianhydrides represented by the above formula (C1), B ^{1 in} the formula is represented by the formula (X-1), (X-2), (X-4), (X-5), (X -6), (X-7) , (X-8), (X-9), (X-11) and (preferably acid dianhydride represented by X-12), wherein B ¹ is the formula Acid dianhydrides represented by (X-1), (X-2), (X-6), (X-11) and (X-12) are particularly preferred.
In addition, the acid dianhydride component includes an acid dianhydride represented by the above formula (1-1) and an acid dianhydride represented by the above formula (C1) as long as the effects of the present invention are not impaired. Other acid dianhydrides other than those may be used.

In the acid dianhydride component, when the alicyclic tetracarboxylic dianhydride is used together with the acid dianhydride represented by the formula (1-1) of the present invention, the acid dianhydride component is represented by the formula (1-1). The ratio of the acid dianhydride and the alicyclic tetracarboxylic dianhydride is usually determined by the formula (1-1): acid dianhydride: alicyclic tetracarboxylic dianhydride = 1 : 0.5 to 1: 4. By setting it as such a range, the polyamic acid which gives the polyimide of high heat resistance, high flexibility, high transparency, and low retardation can be obtained with sufficient reproducibility.

（式中、Ｂ²は、式（Ｙ－１）～式（Ｙ－３４）からなる群から選ばれる２価の基を表す。）

（式中、＊は結合手を表す。） From the standpoint of obtaining a polyamic acid (and corresponding polyimide) that gives a polyimide film having not only excellent heat resistance, flexibility and transparency, but also low retardation characteristics, with good reproducibility (and corresponding) The diamine component used in the production of the polyimide is preferably an aromatic diamine, more preferably a diamine represented by the following formula (A1).

(Wherein B ² represents a divalent group selected from the group consisting of formulas (Y-1) to (Y-34)).

(In the formula, * represents a bond.)

Among the diamines represented by the above formula (A1), B ² in the formula is the formula (Y-12), (Y-13), (Y-14), (Y-15), (Y-18) Diamines represented by (Y-27), (Y-28), (Y-30) and (Y-33) are preferred, and the B ² is represented by the formula (Y-12), (Y-13), Diamines represented by (Y-14), (Y-15) and (Y-33) are particularly preferred.
Moreover, in the range which does not impair the effect of this invention, you may use other diamine compounds other than the diamine represented by the said Formula (A1) for the said diamine component.

From the viewpoint of obtaining a polyamic acid (and corresponding polyimide) that gives a polyimide film having high heat resistance, high flexibility, high transparency, and low retardation with good reproducibility, it is used for producing the polyamic acid (and corresponding polyimide) of the present invention. The content of the aromatic diamine in the diamine component is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol%, still more preferably 80 mol%, still more preferably 90 mol%, most preferably 100 mol%.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄ、ｅ、Ｂ¹及びＢ²は、上記と同じ意味を表す。） In addition, the acid dianhydride represented by the above formula (1-1) and the acid dianhydride represented by the above (C1) are used as the above acid dianhydride component, and the above formula (A1) as the above diamine component. When the diamine represented by the formula (1) is used, the polyamic acid has a monomer unit represented by the following formula (4-1) and a monomer unit represented by the following formula (4-2).

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d, e, B ¹ and B ² represent the same meaning as described above.)

The method for obtaining the polyamic acid of the present invention is not particularly limited, and the aforementioned acid dianhydride component and diamine component may be reacted and polymerized by a known method.
The ratio of the number of moles of the acid dianhydride component to the number of moles of the diamine component when synthesizing the polyamic acid is acid dianhydride component / diamine component = 0.8 to 1.2.

Examples of the solvent used for the synthesis of polyamic acid include m-cresol, N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N- Examples include methyl caprolactam, dimethyl sulfoxide (DMSO), tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl phosphoramide, and γ-butyrolactone. These may be used alone or in combination. Furthermore, even if it is a solvent which does not melt | dissolve a polyamic acid, you may use it in addition to the said solvent within the range in which a uniform solution is obtained.
The temperature of the polycondensation reaction can be selected from -20 to 150 ° C, preferably -5 to 100 ° C.

The polyamic acid-containing solution obtained by the polymerization reaction of the polyamic acid described above can be used as it is, or after diluting or concentrating, as a polyimide film forming composition described later. Further, a poor solvent such as methanol or ethanol is added to the polyamic acid-containing solution to precipitate and isolate the polyamic acid, and the isolated polyamic acid is redissolved in an appropriate solvent to obtain a polyamic acid-containing solution. It can also be used as a composition for forming a polyimide film.
The solvent for diluting the polyamic acid-containing solution and the solvent for re-dissolving the isolated polyamic acid are not particularly limited as long as the obtained polyamic acid can be dissolved. For example, m-cresol, 2-pyrrolidone NMP, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, DMAc, DMF, and γ-butyrolactone.

Further, even if the solvent alone does not dissolve the polyamic acid, it can be used in addition to the above solvent as long as the polyamic acid does not precipitate. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and 1-butoxy-2-propanol. 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate isoamyl ester, etc. .

The polyimide of the present invention can be obtained by subjecting the above-described polyamic acid to dehydration ring closure (thermal imidization) by heating, or chemically ring closure using a known dehydration ring closure catalyst.
The method by heating can be performed at an arbitrary temperature of 100 to 300 ° C., preferably 120 to 250 ° C.
The method of chemically cyclizing can be performed, for example, in the presence of pyridine, triethylamine, 1-ethylpiperidine or the like and acetic anhydride, and the temperature at this time is an arbitrary temperature of −20 to 200 ° C. You can choose.

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ａ、ｂ、ｃ、ｄ、ｅ、Ｂ¹及びＢ²は、上記と同じ意味を表す。） The polyimide obtained from the polyamic acid having the monomer unit represented by the above formula (4-1) and the monomer unit represented by the above formula (4-2) thus obtained is represented by the following formula (5-1). And a monomer unit represented by the following formula (5-2).

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d, e, B ¹ and B ² represent the same meaning as described above.)

The polyimide-containing solution (hereinafter also referred to as polyimide solution) obtained by the above-described polyamic acid ring-closing reaction can be used as it is, or after diluting or concentrating, as a film-forming composition described later. In addition, a poor solvent such as methanol or ethanol is added to the polyimide-containing solution to precipitate the polyimide to isolate the polyimide, and the isolated polyimide is redissolved in an appropriate solvent. Can be used as
The solvent for re-dissolution is not particularly limited as long as it can dissolve the obtained polyimide. For example, m-cresol, 2-pyrrolidone, NMP, N-ethyl-2-pyrrolidone, N-vinyl-2 -Pyrrolidone, DMAc, DMF, γ-butyrolactone and the like.

Further, even if the solvent alone does not dissolve the polyimide, it can be used in addition to the above solvent as long as the polyimide does not precipitate. Specific examples thereof include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and 1-butoxy-2-propanol. 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactate isoamyl ester, etc. .

In the present invention, the number average molecular weight of the polyamic acid and the corresponding polyimide is preferably 5,000 or more, more preferably 7,000 or more, and still more from the viewpoint of improving the flexibility, strength, etc. of the thin film obtained. Preferably, it is 10,000 or more, and from the viewpoint of ensuring the solubility of the resulting polyamic acid and the corresponding polyimide, it is preferably 200,000 or less, more preferably 100,000 or less, and even more preferably 50,000. It is as follows. In the present specification, the number average molecular weight is a value measured by a GPC (gel permeation chromatography) apparatus and calculated as a polystyrene equivalent value.

[Film-forming composition / Polyimide film-forming composition]
The film forming composition containing the polyimide of the present invention described above and an organic solvent, and the polyimide film forming composition containing the polyamic acid of the present invention and an organic solvent are also objects of the present invention. Here, the composition for forming a film and the composition for forming a polyimide film of the present invention are uniform and phase separation is not recognized.

<Organic solvent>
The composition for forming a film or the composition for forming a polyimide film of the present invention contains an organic solvent in addition to the polyimide or polyamic acid. This organic solvent is not specifically limited, For example, the thing similar to the specific example of the reaction solvent used at the time of preparation of the said polyamic acid and a polyimide is mentioned. More specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, γ- Examples include butyrolactone. In addition, an organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and γ-butyrolactone are preferable in view of obtaining a film having high flatness with good reproducibility.

The blending amount of the solid content in the film-forming composition or polyimide film-forming composition of the present invention is usually about 0.5 to 30% by mass, preferably about 5 to 25% by mass. When the solid content concentration is less than 0.5% by mass, the film forming efficiency is lowered in producing the film, and the viscosity of the film forming composition or the polyimide film forming composition is lowered, so that the surface is uniform. It is difficult to obtain a coating film. On the other hand, when the solid content concentration exceeds 30% by mass, the viscosity of the film forming composition or the polyimide film forming composition becomes too high, and there is a possibility that the film forming efficiency is deteriorated or the surface uniformity of the coating film is lacking. . In addition, solid content here means the total mass of components other than an organic solvent, and even if it is a liquid monomer etc., it shall be included in a weight as solid content.
The viscosity of the composition for forming a film or the composition for forming a polyimide film is appropriately set in consideration of the thickness of the film to be produced, but a film having a thickness of about 5 to 50 μm can be obtained with good reproducibility. When intended, it is usually about 500 to 50,000 mPa · s at 25 ° C., preferably about 1,000 to 20,000 mPa · s.

The film-forming composition or polyimide film-forming composition of the present invention may be blended with various other organic or inorganic low-molecular or high-molecular compounds in addition to impart processing characteristics and various functionalities. . For example, a catalyst, an antifoaming agent, a leveling agent, a surfactant, a dye, a plasticizer, fine particles, a coupling agent, a sensitizer, and the like can be used.
The proportion of the polyimide or polyamic acid in the solid content of the film-forming composition or the polyimide film-forming composition of the present invention, including the case where other components are included, can be 70 to 100% by mass.
The film-forming composition or the polyimide film-forming composition of the present invention can be obtained by dissolving the polyimide or polyamic acid obtained by the above-described method in the above-mentioned organic solvent, and after the preparation of the polyimide or polyamic acid. If desired, the organic solvent may be further added to the reaction solution.

[film]
The organic solvent is removed by applying the film forming composition or the polyimide film forming composition of the present invention described above to a substrate, drying and heating, and having high heat resistance, high transparency, and moderate flexibility. It is possible to obtain a film (polyimide film) having high properties and an appropriate linear expansion coefficient and having a small retardation.
That is, the film-forming composition (polyimide-containing solution) applied on the substrate is heated and the solvent is evaporated, whereby the film of the present invention containing polyimide can be obtained. It consists of the solid content of the composition.
Or the film | membrane of this invention containing a polyimide can be obtained by heating the said composition for polyimide film formation (polyamic acid containing solution) apply | coated on the base material, and performing an imidation reaction, evaporating a solvent. The film is made of a solid content of the polyimide film-forming composition and contains an imidized product of polyamic acid in the solid content. The film, that is, a film (thin film) containing the polyimide is also an object of the present invention. .

Examples of the base material used for the production of the film include plastics (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetylcellulose, ABS, AS, norbornene resin, etc.), metal, stainless steel (SUS). Wood, paper, glass, silicon wafer and slate.
In particular, in the case of application as a substrate material for electronic devices, it is preferable that the base material to be applied is a glass or silicon wafer from the viewpoint that existing equipment can be used, and the resulting film has good peelability. Of these, glass is more preferable. The linear expansion coefficient of the substrate to be applied is preferably 35 ppm / ° C. or less, more preferably 30 ppm / ° C. or less, still more preferably 25 ppm / ° C. or less, more preferably from the viewpoint of the warp of the substrate after coating. Is 20 ppm / ° C. or less.

The coating method of the film-forming composition or the polyimide film-forming composition on the substrate is not particularly limited, and examples thereof include cast coating, spin coating, blade coating, dip coating, and roll coating. Method, bar coating method, die coating method, ink jet method, printing method (eg, relief printing, intaglio printing, planographic printing, screen printing, etc.) and the like, and these can be appropriately used depending on the purpose.

The heating temperature is usually about 40 to 500 ° C, preferably 300 ° C or less. If it exceeds 300 ° C., the resulting film becomes brittle, and it may not be possible to obtain a film particularly suitable for display substrate applications.
In consideration of the heat resistance and linear expansion coefficient characteristics of the obtained film, the applied film-forming composition or polyimide film-forming composition is heated at 40 ° C. to 100 ° C. for 5 minutes to 2 hours, and then stepwise. It is desirable to raise the heating temperature to 175 ° C. to 280 ° C. for 30 minutes to 2 hours. Thus, the low thermal expansion characteristic can be expressed by heating at a temperature of two or more stages of drying the solvent and promoting molecular orientation.
In particular, the applied film-forming composition is heated at 40 ° C. to 100 ° C. for 5 minutes to 2 hours, and then heated from 100 ° C. to 175 ° C. for 5 minutes to 2 hours, and then from 175 ° C. to 280 ° C. for 5 minutes. Heating for ~ 2 hours is preferred.
In the case of a composition for forming a polyimide film containing a polyamic acid, for example, in the range of 40 to 100 ° C., in the range of 100 to 150 ° C., the coating film is heated to allow the imidization reaction while evaporating the solvent. It can be heated stepwise in the range, 180-300 ° C.
Examples of the appliance used for heating include a hot plate and an oven. The heating atmosphere may be under air or under an inert gas such as nitrogen, and may be under normal pressure or under reduced pressure, and different pressures are applied at each stage of heating. May be.

The thickness of the film is usually about 1 to 60 μm, preferably about 5 to 50 μm, particularly when used as a substrate for a flexible display. A film having a desired thickness can be obtained by adjusting the thickness of the coating before heating. Form.
In addition, there is no limitation in particular as a method of peeling the film | membrane formed in this way from a base material, The film | membrane is cooled with the base material, it cuts into a film | membrane, and it peels by giving tension through a roll or a roll. And the like.

And the board | substrate for flexible devices consisting of the film | membrane formed from the said composition for film formation or the composition for polyimide film formation, ie, the hardened | cured material (composition for film formation) of the said composition for film formation or the composition for polyimide film formation A substrate for a flexible device comprising a cured product of a solid product) or a cured product of a composition for forming a polyimide film (imided product of polyamic acid in the solid content of a composition for forming a polyimide film) is also an object of the present invention. is there.

The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples.
Abbreviations of reagents used are as follows: TH: Triptycene hydroquinone (9,10-dihydro-9,10- [1,2] benzenoanthracene-1,4-diol)
HTAC: Anhydrous hydrated trimellitic chloride
TH-HTAC-CA: Triptycene hydroquinone HTAC carboxylic acid TH-HTAC: Triptycene hydroquinone HTAC
THF: Tetrahydrofuran CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride TFMB: 2,2′-di (trifluoromethyl) benzidine BODAxx: bicyclo [2,2,2] octane-2,3 5,6-tetracarboxylic dianhydride

In addition, the apparatus and conditions used for sample preparation and physical property analysis and evaluation are as follows.
1) HPLC analysis column: Inertsil ODS-3, 5 μm, 4.6 mm × 250 mm
Oven: 40 ° C
Detection wavelength: 254 nm
Flow rate: 1.0 mL / min Eluent:
TH-HTAC-CA: acetonitrile / 0.5% phosphoric acid aqueous solution = 50/50 Sample injection amount: 5 μL
TH-HTAC: acetonitrile / 0.5% phosphoric acid aqueous solution = 50/50 Sample injection volume: 5 μL *
* TH-HTAC is diluted 100 times with eluent, stirred at 70 ° C for 1 hour, and measured as TH-HTAC-CA 2) ¹ HNMR analyzer: Fourier transform superconducting nuclear magnetic resonance apparatus (FT-NMR) (INOVA-400 (Varian) 400MHz
Solvent: DMSO-d6
Internal standard: Tetramethylsilane (TMS)

[1] Synthesis of Compound <Example 1-1> (Synthesis of TH-HTAC-CA)

Under a nitrogen atmosphere, TH (30 g) and HTAC (68.1 g) were dissolved in tetrahydrofuran (THF, 300 g) and cooled to 5 ° C. To this solution, a mixed solution of pyridine (24.9 g) and tetrahydrofuran (90 g) was added dropwise over 30 minutes, and the solution was washed with tetrahydrofuran (30 g). After stirring for 19 hours, the reaction solution was cooled to 5 ° C., water (1260 g) was added, the temperature was raised to 25 ° C., and the mixture was stirred for 30 minutes. The precipitate was filtered and washed three times with water (90 g), and the resulting filtered product (121.4 g) was dried under reduced pressure at 70 ° C. to obtain 82.5 g of a TH-HTAC crude product.
Next, this TH-HTAC crude product (82.5 g) was added to a mixed solution of ethyl acetate (787 g) and 0.5% aqueous phosphoric acid solution (787 g), and this suspension solution was refluxed (78 ° C.). The mixture was stirred for 6 hours to completely dissolve the crude product. The solution was cooled to 25 ° C., the aqueous layer was removed, water (700 g) was added to the organic layer, the mixture was stirred for 30 minutes, and then the aqueous layer was removed. The obtained organic layer was concentrated and then dried under reduced pressure at 70 ° C. to obtain 82.5 g of a TH-HTAC-CA crude product. This TH-HTAC-CA crude product (82.5 g) was added to acetonitrile (339 g), heated to 70 ° C., stirred for 1 hour, and then cooled to 5 ° C. The precipitate was filtered, washed twice with acetonitrile (339 g), and the obtained filtered product was dried under reduced pressure at 70 ° C. to obtain 37.9 g of a TH-HTAC-CA isomer mixture (yield: 53 0.0% (2 Steps), HPLC area (retention time; 4.9 min, 5.1 min, 5.6 min, 6.2 min, 6.4 min); 96.5%).

<Example 1-2> (Synthesis of TH-HTAC)
TH-HTAC-CA (37.9 g) was added to acetic anhydride (114 g), stirred for 30 minutes under reflux conditions (130 ° C.), and then the reaction solution was cooled to 25 ° C. The precipitate was filtered with a nitrogen stream, and the filtrate was washed with acetic anhydride (38 g). Hexane was added to the obtained undried residue and dried under reduced pressure at 130 ° C. to obtain 31.0 g of TH-HTAC. (Yield; 86.3%, HPLC area (retention time; 4.9 min, 5.6 min, 6.4 min); 96.8%).
This crystal was confirmed to be a TH-HTAC isomer mixture (35.1: 35.5: 26.3) from ¹ HNMR analysis and HPLC analysis results.
¹ HNMR (DMSO-d6, δ ppm): 7.4 (m, 4H), 7.0 (m, 4H), 6.9 (m, 2H), 5.6 (m, 2H), 3.7 ( m, 2H), 3.4 (m, 2H), 3.0 (m, 2H), 2.5 (m, 2H), 2.2-1.7 (m, 10H).

　窒素注入／排出口を有しディーン・スターク装置及びメカニカルスターラーが取り付けられた２５０ｍＬ三口反応フラスコ内に、ＴＦＭＢ　６．４０４６ｇ（０．０２モル）を入れた。その後すぐにγ－ブチロラクトン（ＧＢＬ）１６．４７４ｇを加え、撹拌を開始した。ＴＦＭＢが溶媒に完全に溶解した後、ＢＯＤＡｘｘ　２．５ｇ（０．０１モル）をＧＢＬ　１４．１２ｇおよび１－エチルピペリジン　１．０２４ｇとともに加え、窒素雰囲気下で３時間、１５０℃に加熱した。その後、ＴＨ－ＨＴＡＣ　１．２９３２ｇ（０．００２モル）をＧＢＬ　７．０６ｇとともに加え、窒素雰囲気下、１４０℃にて１時間反応させた。その後、反応混合物にＣＢＤＡ　１．５６８ｇ（０．００８モル）、ＧＢＬ　９．４１ｇおよび１－エチルピペリジン　０．２３ｇを加え、温度を１８０℃に上げて３時間反応させた。その後、固形分濃度が１５質量％となるようにＧＢＬを加えて反応混合物を希釈し、希釈した反応混合物を４時間さらに反応させ、その後、固形分濃度が１２質量％となるようにＧＢＬを加えた。
　次いで、得られた反応混合物を５００ｇのメタノール中に加えて３０分間撹拌し、ろ過によって析出物であるポリイミドを回収した。この操作を３回繰り返した。
　最後に、得られたポリイミド中のメタノール残渣を真空オーブンにより、１２０℃で８時間乾燥し、乾燥したポリイミド（ＩＩＩ）を得た（１０．５ｇ、収率：９５．１％）。 [2] Production of Polyimide <Example 1-3 Production of Polyimide (III) [TH-HTAC: CBDA: BODAxx: TFMB = 10: 40: 50: 100 (molar ratio)]

In a 250 mL three-necked reaction flask with a nitrogen inlet / outlet and equipped with a Dean-Stark apparatus and a mechanical stirrer was placed 6.4046 g (0.02 mol) of TFMB. Immediately thereafter, 16.474 g of γ-butyrolactone (GBL) was added and stirring was started. After TFMB was completely dissolved in the solvent, 2.5 g (0.01 mol) of BODAxx was added along with 14.12 g of GBL and 1.024 g of 1-ethylpiperidine and heated to 150 ° C. for 3 hours under a nitrogen atmosphere. Thereafter, 1.2932 g (0.002 mol) of TH-HTAC was added together with 7.06 g of GBL, and the mixture was reacted at 140 ° C. for 1 hour in a nitrogen atmosphere. Thereafter, 1.568 g (0.008 mol) of CBDA, 9.41 g of GBL and 0.23 g of 1-ethylpiperidine were added to the reaction mixture, and the temperature was raised to 180 ° C. and reacted for 3 hours. Then, GBL is added to dilute the reaction mixture so that the solid content concentration is 15% by mass, and the diluted reaction mixture is further reacted for 4 hours, and then GBL is added so that the solid content concentration is 12% by mass. It was.
Next, the obtained reaction mixture was added to 500 g of methanol, stirred for 30 minutes, and the polyimide as a precipitate was collected by filtration. This operation was repeated three times.
Finally, the methanol residue in the obtained polyimide was dried in a vacuum oven at 120 ° C. for 8 hours to obtain dried polyimide (III) (10.5 g, yield: 95.1%).

[3] Preparation of polyimide solution (varnish) and preparation of polyimide film At room temperature, 3 g of the polyimide (III) was dissolved in N-methyl-2-pyrrolidone (NMP) so that the solid content concentration was 12% by mass. The obtained polyimide solution was filtered under pressure using a 5 μm filter.
Then, the filtered polyimide solution was apply | coated on the glass substrate, and it heated in order at 50 degreeC for 30 minutes, 140 degreeC for 30 minutes, and 200 degreeC for 60 minutes in air | atmosphere, and obtained the film | membrane of transparent polyimide. Then, the obtained polyimide film was peeled off by mechanical cutting to obtain an evaluation sample.

Heat resistance and optical characteristics of the thin film (evaluation sample) produced by the above-described procedure, that is, linear thermal expansion coefficient (CTE) at 50 ° C. to 200 ° C. and 200 ° C. to 250 ° C., light transmittance (T _{400 nm} , T _{550 nm} ) 5% weight loss temperature (Td _5% ), CIE b ^* value (yellow evaluation), retardation (R _th , R ₀ ) and birefringence (Δn) were evaluated according to the following procedures. The number average molecular weight and weight average molecular weight of the polyimide were also measured according to the following procedure. The results are shown in Table 1.

1) CIE b value (CIE b ^* )
The CIE b value (CIE b ^* ) was measured using a SA4000 spectrometer manufactured by Nippon Denshoku Industries Co., Ltd., at room temperature, using air as a reference.
2) Light transmittance (transparency) ( _T400nm , _T550nm )
Light transmittances at wavelengths of 400 nm and 550 nm (T _{400 nm} , T _{550 nm} [%]) were measured using Shimadzu Corporation UV-Visible Spectrophotometer UV-Visible 3600 at room temperature with reference air. .
3) Retardation ( _Rth , _R0 )
Thickness direction retardation (R _th ) and in-plane retardation (R ₀ ) were measured at room temperature using KOBURA 2100ADH manufactured by Oji Scientific Instruments.
The thickness direction retardation (R _th ) and the in-plane retardation (R ₀ ) are calculated by the following equations.
R ₀ = (Nx−Ny) × d = ΔNxy × d
R _th = [(Nx + Ny) / 2−Nz] × d = [(ΔNxz × d) + (ΔNyz × d) / 2
Nx, Ny: Two in-plane orthogonal refractive indexes (Nx> Ny, Nx is also called the slow axis, and Ny is also called the fast axis)
Nz: Refractive index in the thickness (perpendicular) direction with respect to the surface d: Film thickness ΔNxy: Difference between two refractive indexes in the surface (Nx−Ny) (birefringence)
ΔNxz: difference between in-plane refractive index Nx and thickness direction refractive index Nz (birefringence)
ΔNyz: difference between in-plane refractive index Ny and thickness direction refractive index Nz (birefringence)
4) Linear expansion coefficient (CTE)
Each evaluation sample was cut into a size of 5 mm in width and 16 mm in length, and this was first heated at 10 ° C./min and heated to 50 ° C. to 300 ° C. (first heating) using TMA Q400 manufactured by TA Instruments. Then, the temperature is lowered at 10 ° C./min and cooled to 30 ° C., then the temperature is raised at 10 ° C./min and heated to 30 ° C. to 410 ° C. (second heating). The linear expansion coefficient (CTE [ppm / ° C.]) at 200 ° C. and 200 ° C. to 250 ° C. was measured. Note that a load of 0.05 N was applied through the first heating, cooling, and second heating.
5) 5% weight loss temperature (Td _5% )
5% weight loss temperature (Td _5% [° C.]) is measured by using TGA Q500 manufactured by TA Instruments Inc. and raising the temperature of about 5 to 10 mg of resin thin film to 50 to 800 ° C. at 10 ° C./min in nitrogen. I asked for it. The weight at 150 ° C. was set to 0% weight reduction.
6) Film thickness The film thickness of the obtained resin thin film was measured with a thickness gauge manufactured by TECLOCK Co., Ltd.
7) In-plane birefringence (Δn)
Using the thickness direction retardation (R _th ) obtained by the above <3) retardation>, the following formula was used.
ΔN = [R _th / d (film thickness)] / 1000
8) Number average molecular weight (Mn) and weight average molecular weight (Mw)
The number average molecular weight (hereinafter abbreviated as Mn) and the weight average molecular weight (hereinafter abbreviated as Mw) were measured by a polymer sample filtered through a 0.45 μm filter made of polytetrafluoroethylene (PTFE). ), Showdex GPC-101, column: KD803 and KD805, column temperature: 50 ° C., elution solvent: DMF, flow rate: 1.5 ml / min, calibration curve: standard polystyrene.

As shown in Table 1, the polyimide film produced using the novel acid dianhydride of the present invention has a very low retardation R _th in the thickness direction of less than 500 nm and an in-plane retardation R ₀ of less than 5. The result has a value. Further, the transmittance at a wavelength of 400 nm (T _{400 nm} ), the transmittance at a wavelength of 550 nm (T _{550 nm} ), the CTE value at 50 ° C.-200 ° C., and the CTE value at 200 ° C.-250 ° C. were different from each other. And it was confirmed that it has high heat resistance as shown in the Td _5% value.
The novel acid dianhydrides of the present invention are believed to have a unique alignment direction due to the bulky structure that breaks the conjugated system and results in a larger free volume for light transmission, and that in the polyimide membrane It is thought that the performance which was excellent in the rate and retardation (phase difference) is brought about.
Thus, the polyimide film produced using the novel acid dianhydride of the present invention has the characteristics of high transparency (high light transmittance), heat resistance, and low retardation, that is, the base of the flexible display substrate. It can be expected that the film satisfies the necessary requirements as a film and can be particularly suitably used as a base film of a flexible display substrate.

Claims (16)

A polyamic acid obtained by reacting an acid dianhydride component and a diamine component,
A polyamic acid, wherein the acid dianhydride component includes an acid dianhydride represented by the following formula (1-1).

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. ) The polyamic acid according to claim 1, wherein the diamine component contains a diamine represented by the formula (A1).

(Wherein B ² represents any group selected from the group consisting of formula (Y-1) to formula (Y-34)).

(In the formula, * represents a bond.) The polyamic acid according to claim 1 or 2, wherein the acid dianhydride component further contains a tetracarboxylic dianhydride represented by the formula (C1).

[Wherein B ¹ represents any group selected from the group consisting of formulas (X-1) to (X-12)).

(In the formula, a plurality of R's independently represent a hydrogen atom or a methyl group, and * represents a bond.) The composition for polyimide film formation containing the polyamic acid as described in any one of Claims 1 thru | or 3, and the organic solvent. The polyimide film formed using the composition for polyimide film formation of Claim 4. A flexible device substrate comprising the polyimide film according to claim 5. The polyimide obtained by imidating the polyamic acid as described in any one of Claims 1 thru | or 3. A film-forming composition comprising the polyimide according to claim 7 and an organic solvent. Polyimide film formed by using the film forming composition according to claim 8. A flexible device substrate comprising the polyimide film according to claim 9. An acid dianhydride characterized by being represented by the formula (1-1):

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. ) The acid dianhydride according to claim 11, which is represented by the formula (1-2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e have the same meaning as described above.) The acid dianhydride according to claim 12, which is represented by the formula (1-3).

A tetracarboxylic acid represented by the formula (2-1):

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
R ⁶ and R ⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms,
a and b each independently represent an integer of 0 to 4,
c and d each independently represent an integer of 0 to 9,
e represents an integer of 0 to 2. ) The tetracarboxylic acid according to claim 14, which is represented by the formula (2-2).

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , a, b, c, d and e have the same meaning as described above.) The tetracarboxylic acid according to claim 15, which is represented by the formula (2-3).