JP7415218B2 - Tetracarboxylic dianhydride, polyamic acid, polyimide and polyimide solution - Google Patents

Description

The present invention relates to a polyimide with high solvent solubility, excellent heat resistance and dimensional stability, and a tetracarboxylic dianhydride that provides the polyimide.

Polyimide has the highest heat resistance, flame retardancy, and excellent mechanical properties among existing resins, so it is used in insulating materials for a variety of applications, mainly in the electronics field. Among polyimides in particular, polyimides with aromatic or heterocyclic rings in their skeletons have excellent heat resistance and flame retardancy, but they are insoluble in general organic solvents and do not melt even at high temperatures, making it difficult to process polyimides themselves. be.

Therefore, in order to obtain molded products such as polyimide films that have aromatic rings or heterocycles in their skeletons, polyamic acid is usually produced by polyaddition of tetracarboxylic dianhydride and diamine in equimolar amounts at room temperature in an amide solvent. After applying the varnish onto a substrate and drying it to form a film, this is heat-treated at a high temperature of 350°C or higher (called a dehydration ring-closing reaction or a thermal imidization reaction) to form a polyimide. The process of making a film is common. This process is usually applied when producing a single polyimide film or a copper-clad laminate.

However, when forming a polyimide insulating layer after mounting various electronic components on electronic circuits, it is necessary to avoid damage to the electronic components that coexist with the insulating layer. Unable to produce film.

An effective method for solving this problem is to use a solvent-soluble (solution processable) polyimide. In that case, it becomes possible to easily form a heat-resistant insulating layer by simply applying polyimide varnish to a location where an insulating layer is desired to be formed and then drying the polyimide varnish.

Therefore, in order to impart solvent solubility to polyimide, which is originally insoluble in solvents, it is generally recommended to reduce intermolecular forces by introducing greatly bent structural units or bulky side chains into the polyimide's molecular structure. (For example, see Non-Patent Document 1).

However, the polyimide having the above structure has a lower heat resistance, more specifically, a lower glass transition temperature (T _g ) than a polyimide without the above structure. Therefore, it is not easy in principle to achieve both the excellent solution processability and high heat resistance (high T _g ) of polyimide.

Furthermore, as electronic circuits have become more sophisticated in recent years, there has been an increasing demand for thermal dimensional stability of the insulating layer itself formed of polyimide films. If the thermal dimensional stability of the insulating layer is low, the insulating layer will repeatedly undergo large thermal expansion and contraction during various thermal cycles in various device manufacturing processes, and the stress generated will cause the bonding interface of dissimilar metal layers, etc. There is a risk of adverse effects such as poor adhesion and peeling, breakage of fragile inorganic electrode circuits, misalignment of electronic components, and warping of laminates.

In order to improve the thermal dimensional stability of the insulating layer, the coefficient of linear thermal expansion (hereinafter sometimes referred to as CTE) should be made as low as possible, but as mentioned above, in order to ensure solution processability, polyimide molecules It is known that introducing a largely bent structural unit or a bulky side chain into the structure also causes an increase in CTE (see, for example, Non-Patent Document 2). Therefore, it has not been easy in principle to achieve both solution processability and thermal dimensional stability, that is, low thermal expansion properties of polyimide.

J. Polym. Sci., Part A, 41, 3249-3260 (2003). Polym. J., 39, 610-621 (2007).

An object of the present invention is to provide a polyimide that has excellent solution processability, heat resistance, and thermal dimensional stability, and a tetracarboxylic dianhydride that is a monomer of the polyimide.

As a result of intensive research to solve the above problems, the present inventors discovered that a polyimide obtained from the tetracarboxylic dianhydride shown below has excellent solution processability, heat resistance, and thermal dimensional stability. The present invention has now been completed.

That is, the gist of the present invention is shown below.

[1] General formula (1) below:

（一般式（１）中、Ｘ_１はエステル基またはエーテル基を表す。）
で表されるテトラカルボン酸二無水物。

(In general formula (1), X ₁ represents an ester group or an ether group.)
Tetracarboxylic dianhydride represented by

[2] General formula (2) below:

（一般式（２）中、Ａは２価の芳香族基または脂肪族基を表し、Ｘ_１はエステル基またはエーテル基を表す。）
で表される繰り返し単位を有するポリアミド酸。

(In general formula (2), A represents a divalent aromatic group or aliphatic group, and X ₁ represents an ester group or an ether group.)
A polyamic acid having a repeating unit represented by:

[3] General formula (3) below:

（一般式（３）中、Ａは２価の芳香族基または脂肪族基を表し、Ｘ_１はエステル基またはエーテル基を表す。）
で表される繰り返し単位を有するポリイミド。

(In general formula (3), A represents a divalent aromatic group or aliphatic group, and X ₁ represents an ester group or an ether group.)
A polyimide having a repeating unit represented by

[4] A polyimide solution containing the polyimide according to [3] in a solid content concentration of 5% by weight or more.

[5] A polyimide film containing the polyimide according to [3].

[6] The polyimide according to [3] or the polyimide film according to [5], which has a glass transition temperature of 250° C. or higher.

According to the present invention, a polyimide that simultaneously has excellent solution processability, heat resistance and thermal dimensional stability (low linear thermal expansion), which was difficult to achieve based on the above-mentioned common technical knowledge, and It becomes possible to produce tetracarboxylic dianhydride which gives polyimide.

2 is an infrared absorption spectrum diagram of a polyimide film obtained in Example 2. FIG.

<Tetracarboxylic dianhydride of the present invention and method for producing the same>
The tetracarboxylic dianhydride of the present invention, which is a monomer of the polyimide of the present invention, is represented by the above general formula (1). In the above general formula (1), X ₁ represents an ester group or an ether group, and an ester group is preferable from the viewpoint of ease of manufacturing the tetracarboxylic dianhydride.

The tetracarboxylic dianhydride represented by the above general formula (1) is spiro[fluorene-9,9'-xanthene]-2,7'-diol (the following formula (4):

で表されるビスフェノール）から後述する方法により製造される。まずはじめに、上記式（４）で表されるビスフェノールの製造方法について詳述する。

(bisphenol represented by) by the method described below. First, a method for producing bisphenol represented by the above formula (4) will be described in detail.

The bisphenol represented by the above formula (4) of the present invention is produced by reacting 9-fluorenone (hereinafter sometimes referred to as fluorenone) with resorcinol and hydroquinone in the presence of an acid (hereinafter referred to as bisphenolization). (sometimes called a reaction).

The total amount of resorcinol and hydroquinone used is usually 2 to 15 mol per 1 mol of fluorenone, and preferably 4 to 12 mol from the viewpoint of obtaining the bisphenol represented by the above formula (4) in a higher yield. In addition, the molar ratio of resorcinol and hydroquinone is usually 10:90 to 90:10, preferably 20:1 from the viewpoint of obtaining the bisphenol represented by the above formula (4) in a higher yield. The ratio is 80 to 60:40, more preferably 20:80 to 50:50.

Various acids such as inorganic acids and organic acids can be used as acids used in the bisphenolization reaction.Specifically, inorganic acids include sulfuric acid, hydrogen chloride, hydrochloric acid, phosphoric acid, heteropolyacids, zeolites, and clay minerals. Examples of the organic acids include methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and acidic ion exchange resins. Among these acids, hydrochloric acid or para-toluenesulfonic acid is preferably used from the viewpoint of availability and handling. The amount of acid used is usually 0.01 to 5.0 mol per mol of fluorenone, and preferably 0.05 to 5.0 mol per mol of fluorenone from the viewpoint of obtaining a sufficient reaction rate and ease of post-treatment. Use 1.0 mol. These acids may be used alone or in combination of two or more if necessary.

When carrying out the bisphenolization reaction, a sulfur-containing compound may be present in order to improve the reaction rate. Examples of usable sulfur-containing compounds include mercaptocarboxylic acids, alkylmercaptans, aralkylmercaptans, and salts thereof. Specifically, for example, C _1-16 alkyl mercaptans such as thioacetic acid, β-mercaptopropionic acid, α-mercaptopropionic acid, thioglycolic acid, thioxalic acid, mercaptosuccinic acid, mercaptobenzoic acid, n-butylmercaptan, and dodecylmercaptan. can be mentioned. Among these sulfur-containing compounds, dodecyl mercaptan and β-mercaptopropionic acid are preferably used because of their ease of industrial handling. When using these sulfur-containing compounds, the amount used is usually 0.01 to 1.0 parts by weight per 1 part by weight of fluorenone, and preferably fluorenone from the viewpoint of obtaining a sufficient reaction rate and ease of post-treatment. The amount is 0.01 to 0.50 parts by weight per 1 part by weight. These sulfur-containing compounds may be used alone or in combination of two or more if necessary.

When carrying out the bisphenolation reaction, the reaction may be carried out in the presence of a solvent if necessary. Examples of usable solvents include aliphatic hydrocarbons, aromatic hydrocarbons, ethers, and halogenated hydrocarbons. Examples of aliphatic hydrocarbons include hexane, heptane, octane, and decane; examples of aromatic hydrocarbons include benzene, toluene, xylene, and ethylbenzene; examples of ethers include dialkyl ether such as diethyl ether; Examples include ethers, cyclic ethers such as tetrahydrofuran and dioxane, and examples of halogenated hydrocarbons include aliphatic halogenated hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride, and aromatic ethers such as chlorobenzene and dichlorobenzene. Examples include halogenated hydrocarbons. Among these solvents, aromatic hydrocarbons such as toluene and xylene are preferably used from the viewpoint of availability, handling, reaction rate, and reaction selectivity. When using these solvents, the amount used is usually 0.1 to 20 parts by weight per 1 part by weight of fluorenone, and preferably 5 to 20 parts by weight per 1 part by weight of fluorenone from the viewpoint of obtaining a sufficient reaction rate and from an economical viewpoint. Use 10 parts by weight. These solvents may be used alone or in combination of two or more if necessary.

For the bisphenolation reaction, fluorenone, resorcinol, hydroquinone, an acid, and if necessary a sulfur-containing compound and a solvent are placed in a reaction vessel, and the internal temperature is usually 50 to 200°C, preferably 80 to 140°C, more preferably 120 to 140°C. It is carried out by stirring at °C. Further, from the viewpoint of obtaining a sufficient reaction rate, the reaction may be carried out under normal pressure or reduced pressure under reflux while dehydrating.

After the bisphenolization reaction, the bisphenol represented by the above formula (4) can be extracted from the resulting reaction solution by conventional methods such as neutralization, washing with water, concentration, crystallization, and filtration, if necessary. The obtained bisphenol represented by the above formula (4) can also be purified by conventional methods such as recrystallization, distillation, adsorption, and column chromatography. Moreover, if necessary, the obtained reaction solution may be used as it is for the production of the tetracarboxylic dianhydride of the present invention, which will be described later.

Next, the method for producing the tetracarboxylic dianhydride (tetracarboxylic dianhydride represented by the above general formula (1)) of the present invention will be described in detail. First of all, in the above general formula (1), when the linking group X ₁ is an ester group, that is, the following formula (5):

で表されるテトラカルボン酸二無水物の合成方法について以下に例示する。

The method for synthesizing the tetracarboxylic dianhydride represented by is exemplified below.

The tetracarboxylic dianhydride represented by the above formula (5) is produced by performing an esterification reaction using the bisphenol represented by the above formula (4) and a trimellitic acid anhydride derivative. Methods that can be applied in this case include, for example, a method in which the carboxyl group of bisphenol represented by the above formula (4) and trimellitic anhydride is directly subjected to a dehydration reaction at high temperature, and a method in which dehydration condensation is performed using a dehydrating reagent such as dicyclohexylcarbodiimide. , a method of reacting the diacetate of bisphenol represented by the above formula (4) with trimellitic anhydride at high temperature to deacetate it and esterify it (ester exchange method), carboxyl group of trimellitic anhydride is converted into an acid halide and reacted with the bisphenol represented by the above formula (4) in the presence of a deoxidizing agent (base) (acid halide method), tosyl chloride/N,N-dimethylformamide/ Examples include a method of esterifying the carboxyl group in trimellitic anhydride by activating it using a pyridine mixture. Among the above-mentioned methods, the transesterification method and the acid halide method are preferably applied in terms of economy, reactivity, and simplicity. The production method (esterification reaction) using the acid halide method will be specifically described below.

First, in a reaction container, a solution (hereinafter referred to as solution A) is prepared by dissolving the bisphenol represented by the above formula (4) in a dehydrated solvent, and adding and mixing a base as a deoxidizing agent to the solution. Prepare. Further, in another reaction vessel, a solution (hereinafter, this solution is referred to as Solution B) in which the acid halide of trimellitic acid anhydride is dissolved in a dehydrated solvent is prepared. Subsequently, while stirring, liquid A is added to liquid B at a temperature described later. After the addition is complete, the reaction is completed by further stirring at the temperature described later. Note that during stirring, if stirring becomes difficult due to precipitates, a solvent may be added as appropriate.

The solvent that can be used in the above esterification reaction may be one that does not react with the reaction raw materials and can sufficiently dissolve the raw materials, such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane-bis( Ether solvents such as 2-methoxyethyl) ether, aromatic amine solvents such as picoline and pyridine, ketone solvents such as acetone, methyl ethyl ketone and cyclopentanone, aromatic hydrocarbon solvents such as benzene, toluene and xylene, Halogen-containing solvents such as dichloromethane, chloroform, 1,2-dichloroethane, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, 1,3-dimethyl- Amide solvents such as 2-imidazolidinone, phosphorus-containing solvents such as hexamethylphosphoramide, sulfur-containing solvents such as dimethyl sulfoxide, ester solvents such as γ-butyrolactone, ethyl acetate, butyl acetate, etc. can be used. be. These solvents may be used alone or in combination of two or more if necessary. Among these solvents, ketone solvents and ether solvents are preferred from the viewpoint of ease of solvent distillation, with acetone and tetrahydrofuran being particularly preferred.

The amount of solvent used is such that the solute concentration in the esterification reaction is usually in the range of 5 to 50% by weight, and from the viewpoint of suppressing side reactions, reaction yield, filtration process, solvent distillation, etc. It is preferably in the range of 10 to 40% by weight.

Examples of the acid halide of trimellitic anhydride that can be used in the esterification reaction include trimellitic anhydride chloride, trimellitic anhydride bromide, and the like. The amount of trimellitic anhydride halide to be used is usually 2 to 10 mol per 1 mol of bisphenol represented by the above formula (4), to improve the reaction rate and to remove excess trimellitic anhydride after the reaction is completed. From the viewpoint of ease of removal of acid halide, 2.1 to 4 mol is preferable.

The base used as a deoxidizing agent in the above esterification reaction only needs to be soluble in the solvent used, do not react with the reaction raw materials, and can neutralize by-produced acids. Specifically, for example, pyridine, Organic tertiary amines such as triethylamine and N,N-dimethylaniline can be used, and pyridine is particularly preferably used because it is highly economical and has low toxicity. These bases may be used alone or in combination of two or more as necessary. The amount of the base to be used is, for example, 2.1 to 20 moles per mole of bisphenol represented by the above formula (4), from the viewpoint of improving the reaction rate and making it easy to remove excess base after the reaction is completed. More preferably 3 to 10 moles.

The above esterification reaction is usually carried out at -78°C to 5°C, preferably at -30 to 5°C when adding Part A to Part B. After the addition, stirring is performed at the same temperature for 0.5 to 48 hours, preferably 1 to 24 hours. After the stirring, the mixture may be further stirred at 0 to 100°C, preferably 10 to 50°C, for 0.5 to 48 hours, preferably 1 to 24 hours, in order to complete the esterification.

After the completion of the above-mentioned esterification reaction, the precipitate precipitated by the reaction may be directly separated by filtration, or in order to increase the recovery rate of the product, after distilling off part or all of the solvent used in the reaction, the precipitate may be separated by filtration. may be separated by filtration.

The precipitate separated by filtration is a mixture of the tetracarboxylic dianhydride represented by the above formula (5), a by-product (hydrochloride), and an excess amount of the acid halide of trimellitic anhydride. By washing the precipitate with a non-polar solvent to remove excess acid halide of trimellitic anhydride, and then washing with water to remove hydrochloride and excess base, a product represented by the above formula (5) is obtained. Tetracarboxylic dianhydride can be obtained. In addition, after washing with water, a part of the tetracarboxylic dianhydride represented by the above formula (5) may undergo hydrolysis due to the water washing step, so the obtained tetracarboxylic dianhydride represented by the above formula (5) Ring-closing dehydration treatment may be performed by heating and vacuum drying the carboxylic dianhydride. Further, the tetracarboxylic dianhydride represented by the above formula (5) obtained by the above method may be purified by conventional methods such as recrystallization, adsorption, and column chromatography, if necessary.

Subsequently, among the tetracarboxylic dianhydrides of the present invention (tetracarboxylic dianhydrides represented by the above general formula (1)), in the above general formula (1), when the linking group X ₁ is an ether group, That is, the following formula (6):

で表されるテトラカルボン酸二無水物の合成方法について以下に例示する。

The method for synthesizing the tetracarboxylic dianhydride represented by is exemplified below.

The tetracarboxylic dianhydride represented by the above formula (6) is a bisphenol represented by the above formula (4) and the following general formula (7).

（一般式（７）中、Ｒ_１は分岐を有してもよい炭素数１ ～８のアルキル基または炭素数６ ～２０の単環式もしくは縮合多環式芳香族基を示す。）
で表されるＮ―置換ニトロフタルイミドとを縮合反応させて芳香族ビスイミド化合物を得、該芳香族ビスイミド化合物をアルカリ加水分解してテトラカルボン酸の塩とし、得られたテトラカルボン酸の塩を酸性化することでテトラカルボン酸とし、さらに脱水することにより得ることができる。

(In general formula (7), R ₁ represents an optionally branched alkyl group having 1 to 8 carbon atoms or a monocyclic or fused polycyclic aromatic group having 6 to 20 carbon atoms.)
An aromatic bisimide compound is obtained by condensation reaction with N-substituted nitrophthalimide represented by the formula, and the aromatic bisimide compound is alkali hydrolyzed to obtain a tetracarboxylic acid salt, and the obtained tetracarboxylic acid salt is acidified. It can be obtained by converting into a tetracarboxylic acid and further dehydrating it.

The condensation reaction between the bisphenol represented by the above formula (4) and the N-substituted nitrophthalimide represented by the above general formula (7) is performed by converting the bisphenol represented by the above formula (4) into an alkali metal salt of diphenoxide. The reaction is carried out by reacting this with N-substituted nitrophthalimide at a temperature of 20 to 250°C, preferably 20 to 150°C.

Examples of the N-substituted nitrophthalimide represented by the above general formula (7) include N-phenyl-4-nitrophthalimide and N-methyl-4-nitrophthalimide. The amount of N-substituted nitrophthalimide represented by the above general formula (7) to be used is, for example, 2 mol or more, preferably 2 to 3 mol, per 1 mol of the bisphenol represented by the above formula (4).

Examples of organic solvents that can be used in the condensation reaction include aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as acetone and methyl ethyl ketone; halogenated hydrocarbons such as 1,2-dichloroethane and chlorobenzene; Ethers such as 2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl Examples include aprotic polar solvents such as sulfoxide, N-methyl-2-pyrrolidone, and sulfolane. These organic solvents may be used alone or in combination of two or more if necessary. Further, the amount of these organic solvents to be used is such that the solute concentration in the condensation reaction is usually in the range of 1 to 80% by weight, preferably in the range of 30 to 60% by weight.

Hydrolysis of the aromatic bisimide compound obtained by the above condensation reaction to a tetracarboxylic acid salt is carried out, for example, by heating and stirring the aromatic bisimide compound and a base such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution. be done. After hydrolysis, the obtained tetracarboxylic acid salt can be made into a tetracarboxylic acid by acidifying with an aqueous solution of a mineral acid such as hydrochloric acid or sulfuric acid, and the obtained tetracarboxylic acid can be converted into a tetracarboxylic acid by acidifying it with an aqueous solution of a mineral acid such as hydrochloric acid or sulfuric acid. The acid dianhydride represented by the above formula (6) can be obtained by dehydration by heating and stirring using a dehydrating agent. The tetracarboxylic dianhydride represented by the formula (6) obtained by the above method may be purified by conventional methods such as recrystallization, distillation, adsorption, and column chromatography, if necessary.

<Polyamic acid and polyimide of the present invention>
The polyamic acid of the present invention is represented by the above general formula (2), and the polyimide of the present invention is represented by the above general formula (3). In the above general formulas (2) and (3), X ₁ represents an ester group or an ether group, and an ester group is preferable from the viewpoint of ease of manufacturing the tetracarboxylic dianhydride represented by the above general formula (1). .

In the above general formulas (2) and (3), A represents a divalent aromatic group or an aliphatic group. The divalent aromatic group or aliphatic group in the present invention refers to divalent amines (diamines) that are reacted (polymerized) with the tetracarboxylic dianhydride represented by the above general formula (1) by the method described below. It originates from

Examples of the aromatic diamine constituting the divalent aromatic group include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4- Diaminodurene, 4,4'-methylene dianiline, 4,4'-methylenebis(3-methylaniline), 4,4'-methylenebis(3-ethylaniline), 4,4'-methylenebis(2-methylaniline) , 4,4'-methylenebis(2-ethylaniline), 4,4'-methylenebis(3,5-dimethylaniline), 4,4'-methylenebis(3,5-diethylaniline), 4,4'-methylenebis (2,6-dimethylaniline), 4,4'-methylenebis(2,6-diethylaniline), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2, 4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4, 4'-diaminobenzanilide, benzidine, 3,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine, o-tolidine, m-tolidine, 2,2'-bis(trifluoromethyl)benzidine, 1,4- Bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4, 4'-bis(4-aminophenoxy)biphenyl, bis(4-(3-aminophenoxy)phenyl)sulfone, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2-bis(4-(4 -aminophenoxy)phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, p-terphenylenediamine, etc. Can be mentioned. These diamines may be used alone or in combination of two or more if necessary.

Examples of the aliphatic diamine constituting the divalent aliphatic group include 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(3-methylcyclohexylamine), and 4,4'-methylenebis(3-ethyl cyclohexylamine), 4,4'-methylenebis(3,5-dimethylcyclohexylamine), 4,4'-methylenebis(3,5-diethylcyclohexylamine), isophoronediamine, trans-1,4-cyclohexanediamine, cis- 1,4-Cyclohexanediamine, 1,4-cyclohexanebis(methylamine), 2,5-bis(aminomethyl)bicyclo[2.2.1]heptane, 2,6-bis(aminomethyl)bicyclo[2. 2.1] Heptane, 3,8-bis(aminomethyl)tricyclo[5.2.1.0]decane, 1,3-diaminoadamantane, 2,2-bis(4-aminocyclohexyl)propane, 2,2 -Bis(4-aminocyclohexyl)hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine , 1,8-octamethylenediamine, 1,9-nonamethylenediamine, and the like. These diamines may be used alone or in combination of two or more if necessary.

Among the aromatic or aliphatic diamines mentioned above, diamines with a rigid and linear structure are preferred, and for example, 2,2'-bis(trifluoromethyl)benzidine (hereinafter sometimes referred to as TFMB) is preferably used. .

The polyamic acid and polyimide of the present invention include tetracarboxylic dianhydride represented by the above general formula (1) within a range that does not significantly impair the polymerization reactivity and properties of the polyimide when polymerizing the polyimide of the present invention. It may have a structural unit derived from an aromatic or aliphatic tetracarboxylic dianhydride other than the above. Examples of aromatic tetracarboxylic dianhydrides that can be used in combination include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,3,3',4'-biphenyl. Tetracarboxylic dianhydride, 2,3,2',3'-biphenyltetracarboxylic dianhydride, hydroquinone-bis(trimellitate anhydride), methylhydroquinone-bis(trimellitate anhydride), 1, 4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,4,3',4'-benzophenonetetracarboxylic dianhydride, 2, 3,3',4'-benzophenone tetracarboxylic dianhydride, 2,3,2',3'-benzophenone tetracarboxylic dianhydride, 3,4,3',4'-biphenyl ether tetracarboxylic dianhydride Anhydride, 3,4,2',3'-biphenyl ether tetracarboxylic dianhydride, 2,3,2',3'-biphenyl ether tetracarboxylic dianhydride, 3,4,3',4' -biphenylsulfonetetracarboxylic dianhydride, 3,4,2',3'-biphenylsulfonetetracarboxylic dianhydride, 2,3,2',3'-biphenylsulfonetetracarboxylic dianhydride, 2, Examples include 2'-bis(3,4-dicarboxyphenyl)hexafluoropropanoic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)propanoic dianhydride, and the like.

Examples of aliphatic tetracarboxylic dianhydrides that can be used in combination include bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5-(dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetralin-1,2-dicarboxylic anhydride, tetrahydrofuran-2,3, 4,5-tetracarboxylic dianhydride, bicyclo-3,3',4,4'-tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2, Examples include 3,4-cyclopentanetetracarboxylic dianhydride, etc. These tetracarboxylic dianhydrides may be used alone or in combination of two or more as necessary.

From the viewpoint of heat resistance (physical heat resistance), the polyimide of the present invention preferably has a glass transition temperature of 230°C or higher, more preferably 250°C or higher. The method for measuring the glass transition temperature will be described later in the Examples section.

<Polyimide solution of the present invention>
The polyimide solution of the present invention contains the above-mentioned polyimide and an organic solvent. The polyimide concentration in the polyimide solution is preferably 5% by weight or more in solid content from the viewpoint of ease of manufacturing the polyimide film, and from the viewpoint of ensuring the smoothness of the film coated using the polyimide solution. It is preferably 5 to 40% by weight, particularly 5 to 20% by weight.

Examples of organic solvents contained in the polyimide solution of the present invention include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentane. ketone solvents such as non- and cyclohexanone; ether solvents such as tetrahydrofuran, 1,3-dioxolane and 1,4-dioxane; methyl acetate, ethyl acetate, butyl acetate, γ-butyrolactone, α-acetolactone, β-propio Ester solvents such as lactone and δ-valerolactone; methyl monoglyme (1,2-dimethoxyethane), methyl diglyme (bis(2-methoxyethyl) ether), methyl triglyme (1,2-bis(2- methoxyethoxy)ethane), methyltetraglyme (bis[2-(2-methoxyethoxyethyl)]ether), ethyl monoglyme (1,2-diethoxyethane), ethyldiglyme (bis(2-ethoxyethyl)ether) ) and symmetric glycol diether solvents such as butyl diglyme (bis(2-butoxyethyl) ether); dipropylene glycol methyl ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether , propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-propyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and ethylene glycol monoethyl Examples include ether solvents such as ether. These organic solvents may be used alone or in combination of two or more if necessary.

Among the organic solvents mentioned above, amide solvents, ketone solvents, ether solvents, or mixed solvents thereof are preferable, and it is more preferable to use a single ketone solvent or ether solvent, or a mixed solvent thereof. . Among these organic solvents, amide solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone, and ketone solvents include methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and Cyclohexanone, ether solvents include methyl monoglyme (1,2-dimethoxyethane), methyl diglyme (bis(2-methoxyethyl)ether) and methyl triglyme (1,2-bis(2-methoxyethoxy)ethane) etc. are particularly preferred.

The polyimide solution of the present invention contains inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, surfactants, leveling agents, antifoaming agents, fluorescent Various additives such as a brightener, a crosslinking agent, a polymerization initiator, and a photosensitizer may be included.

A polyimide film can be easily produced from the polyimide solution of the present invention by applying a known method. Specifically, for example, a polyimide solution can be applied onto a support such as a glass substrate using a known method such as a doctor blade, and then dried to produce a polyimide film. Furthermore, it is possible to obtain a laminated film of polyimide/metal foil by coating it on a metal foil such as copper foil using a known method, for example, using a doctor blade, and drying it. When applied to an insulating material for a substrate, an insulating layer can be easily formed by directly coating the device and drying the solvent.

<Method for producing polyamic acid of the present invention>
The method for producing the polyamic acid of the present invention is not particularly limited, and known methods can be applied. More specifically, the diamine constituting the polyamic acid and polyimide of the present invention described above is dissolved in the polymerization solvent described below, and the tetracarboxylic dianhydride represented by the above general formula (1) and, if necessary, Tetracarboxylic dianhydride used in combination is gradually added, and the mixture is stirred at 0 to 100°C, preferably 20 to 60°C, for 0.5 to 100 hours, preferably 1 to 72 hours.

The solvent (polymerization solvent) used in producing polyamic acid should dissolve the monomer and the polyamic acid to be produced and do not react with them. Specifically, for example, N,N-dimethylformamide, N,N-dimethylacetamide, etc. , amide solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, butyl acetate, ethyl acetate, Ester solvents such as isobutyl acetate, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as diethylene glycol dimethyl ether, triethylene glycol, triethylene glycol dimethyl ether, phenol, m-cresol, p-cresol, o-cresol, Phenolic solvents such as 3-chlorophenol and 4-chlorophenol, cyclopentanone, cyclohexanone, acetone, ketone solvents such as methyl ethyl ketone, diisobutyl ketone, and methyl isobutyl ketone, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethoxy Ether solvents such as ethane and dibutyl ether, and other general-purpose solvents include acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, Examples include ethyl cellosolve acetate, butyl cellosolve acetate, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirit, and petroleum naphtha-based solvents. These solvents may be used alone or in combination of two or more if necessary.

The amount of solvent used is such that the monomer concentration is 5 to 50% by weight, preferably 10 to 40% by weight. By carrying out polymerization within the above monomer concentration range, a uniform polyamic acid solution with a high degree of polymerization can be obtained. If the degree of polymerization of the polyamic acid increases too much and the polymerization solution becomes difficult to stir, it may be diluted with the above-mentioned solvent as appropriate.

The usage ratio (mole ratio) of the tetracarboxylic dianhydride (the total amount of the tetracarboxylic dianhydride represented by the above general formula (1) and the tetracarboxylic dianhydride used together if necessary) and the diamine is as follows: Usually, the ratio of tetracarboxylic dianhydride:diamine is in the range of 0.9:1 to 1:0.9, but from the viewpoint of increasing the degree of polymerization of the polyamic acid as much as possible, it is 0.95:1 to 1:0. The ratio is more preferably in the range of 95, and even more preferably 1:1.

The polymerization solution of polyamic acid may be used as it is in the production of polyimide, which will be described later, or may be isolated as a powder by dropping it into a large amount of water or a poor solvent such as methanol, filtering, and drying.

The intrinsic viscosity of the polyamic acid of the present invention obtained by the method described above is usually in the range of 0.3 to 10.0 dL/g from the viewpoint of the toughness of the polyimide film of the present invention and the handleability of the polyamic acid solution. , preferably in the range of 0.5 to 5.0 dL/g. Note that the method for measuring the intrinsic viscosity will be described later in the Examples section.

<Method for producing polyimide of the present invention>
The polyimide of the present invention can be produced by subjecting the polyamic acid obtained by the above method to a dehydration ring closure reaction (imidization reaction). Examples of the imidization reaction method include thermal imidization reaction and chemical imidization reaction.

The thermal imidization reaction is performed by casting a polyamic acid solution onto a substrate made of inorganic glass, copper, aluminum, stainless steel, silicon, etc., and drying it at 40 to 150°C, preferably 50 to 120°C, to form a polyamic acid film. form. This is carried out by heating the substrate at 200 to 400°C, preferably 250 to 350°C, in vacuum or in an inert gas atmosphere such as nitrogen. The thermal imidization reaction is preferably carried out in vacuum or in an inert gas, but it can also be carried out in air. In addition, as a solvent for preparing a polyamic acid solution, the same solvent as the solvent used when manufacturing the polyamic acid mentioned above can be used. In addition, in order to azeotropically distill off water, which is a byproduct of the imidization reaction, a solvent such as toluene or xylene that is azeotropic with water may be added, and a base such as γ-picoline may be used as an imidization catalyst. may be added.

Moreover, the polyimide of the present invention can also be polymerized in one step (one-pot polymerization) without isolating the polyamic acid by reacting a tetracarboxylic dianhydride and a diamine at high temperature in a solvent. The polymerization temperature at this time depends on the boiling point of the solvent, but is usually in the range of 150 to 250°C. Further, if the polyimide is insoluble in the solvent used, the polyimide is obtained as a precipitate, and if it is soluble, it is obtained as a polyimide varnish.

Examples of solvents that can be used in one-pot polymerization include aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, and γ-butyrolactone, as well as phenol and cresol. Examples include phenolic solvents such as. Additionally, during one-pot polymerization, toluene, xylene, etc. may be added to azeotropically distill off water, which is a byproduct of the imidization reaction, and a base such as γ-picoline may be added as an imidization catalyst. You may.

Next, the chemical imidization reaction will be explained in detail. The chemical imidization reaction is carried out by adding a solvent that can be used when producing the above-mentioned polyamic acid, especially the same solvent as the solvent used during the production of the above-mentioned polyamic acid, to the polyamic acid solution obtained by the above method, and adding a suitable amount of the solvent that is easy to stir. While stirring, a dehydration ring-closing agent (chemical imidization agent) consisting of an organic acid anhydride and a tertiary amine as a basic catalyst is added dropwise to the solution at a temperature of 0 to 100°C, preferably 10 to 50°C. Imidization can be chemically completed by stirring for 1 to 72 hours.

Examples of organic acid anhydrides that can be used in the chemical imidization reaction include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, and the like. Acetic anhydride is preferably used because of the ease of handling and separation of the reagent. In addition, as the basic catalyst, pyridine, picoline, N,N-dimethylaniline, N,N-diethylaniline, triethylamine, tripropylamine, tributylamine, etc. can be used, and pyridine is used because of ease of handling and separation of reagents. Suitably used. The amount of organic acid anhydride used is usually in the range of 1 to 20 times the mole, more preferably 1 to 10 times the mole of the theoretical dehydration amount of polyamic acid. Further, the amount of the basic catalyst used is in the range of 0.1 to 2 times the mole of the organic acid anhydride, and more preferably in the range of 0.1 to 1 times the mole.

To complete the chemical imidization reaction, the polyimide isolated as a powder from the reaction solution after chemical imidization is dissolved in a deuterated solvent and ^{the 1} H-NMR spectrum is measured. This can be confirmed by the complete disappearance of the proton peak of ) and the proton peak of carboxyl group (COOH). In addition, by preparing a polyimide film or measuring the infrared absorption spectrum by the KBr method using polyimide powder, for example, the complete disappearance of the amide C=O stretching vibration absorption band derived from polyamic acid and the complete disappearance of the imide C=O stretching vibration absorption band Completion of chemical imidization can be confirmed from the appearance of .

The reaction solution obtained by the chemical imidization method may be used as it is as the polyimide solution described above, or by-products (hereinafter referred to as impurities) such as bases, unreacted chemical imidization agents, and organic acids contained in the reaction solution may be used. ) may be subjected to a purification operation. For purification, known methods can be used. For example, the simplest method is to precipitate polyimide by dropping the imidized reaction solution into a large amount of poor solvent while stirring, and then collect the polyimide powder and wash it repeatedly until impurities are removed. A method of obtaining polyimide powder by drying under reduced pressure can be applied.

The poor solvent that can be used to carry out the above purification operation may be any solvent that can precipitate polyimide, efficiently remove impurities, and is easy to dry.For example, water, alcohols such as methanol, ethanol, isopropanol, etc. These may be used in combination. The amount of the poor solvent is adjusted as appropriate depending on the solvent in the polyimide solution and the type of polyimide.

In addition, if the solid concentration of polyimide contained in the reaction solution dropped into the poor solvent is too high, the polyimide that precipitates will form agglomerates, and impurities may remain in the coarse particles, or the resulting polyimide powder may It may take a long time to redissolve in a solvent. On the other hand, if the concentration is too low, a large amount of poor solvent will be required, which may increase the environmental burden due to waste solvent treatment and increase manufacturing costs. Therefore, the solid content concentration of polyimide contained in the reaction solution dropped into the poor solvent is 20% by weight or less, more preferably 10% by weight or less. If the solid content concentration of polyimide in the reaction solution is not within the above range, it can be adjusted by appropriately concentrating or adding a solvent.

The polyimide powder precipitated in the poor solvent by the method described above is recovered, and the residual solvent is removed by vacuum drying, hot air drying, or the like. The drying temperature and time are not limited as long as the polyimide does not change in quality, and it is preferable to dry at 30 to 150° C. for 3 to 24 hours.

The polyimide powder obtained by the above-mentioned method may be heated and compressed at 200 to 450°C, preferably 250 to 400°C to form a polyimide molded body, or it may be redissolved in an organic solvent to form the above-mentioned polyimide solution. Good too.

In addition, by adding a dehydrating reagent such as N,N-dicyclohexylcarbodiimide or trifluoroacetic anhydride to a polyamic acid solution and stirring it and reacting at 0 to 100°C, preferably 0 to 60°C, polyimide isomers can be obtained. It can be converted to certain polyisoimides. Since polyisoimide has better solvent solubility than polyimide, it is suitable for increasing the solid content concentration. The polyisoimide solution is cast onto a substrate made of inorganic glass, copper, aluminum, stainless steel, silicon, etc., and then heat-treated at 250 to 450°C, preferably 270 to 400°C, to form a thermodynamically more stable polyimide. Can be easily converted.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to examples, but it is not limited to these examples. In addition, the physical property values in the following examples were measured by the following method.

1. Analysis conditions for the production example of bisphenol represented by the above formula (4)

[1] HPLC analysis/device: LC-2010C manufactured by Shimadzu Corporation
・Column: L-column ODS (5 μm, 4.6 mmφ x 250 mm) manufactured by the Chemical Evaluation and Research Organization
-Mobile phase: A liquid = 50% methanol water, B liquid = methanol. In addition, the analysis was conducted by changing the concentration of B solution as described below.
- B solution concentration: 0% (0 minutes) → 100% (30 minutes) → 100% (40 minutes).
・Flow rate: 1.0ml/min ・Column temperature: 40℃
・Detection wavelength: UV 254nm
Note that the content and purity of each component described in the Examples below are the area percentages of HPLC measured under the above conditions.

[2] NMR measurement
¹ H-NMR and ¹³ C-NMR were recorded on a JEOL-ESC400 spectrometer using tetramethylsilane as internal standard and DMSO- _d6 as solvent.

[3] LC-MS measurement/device: Waters Xevo G2 Q-Tof
・Column: L-Column2 ODS (2μm, 2.1mmφ x 100mm) manufactured by the Chemical Evaluation and Research Institute
・Column temperature: 40℃
・Detection wavelength: UV 220-500nm
- Mobile phase: A solution = 10mM ammonium acetate water, B solution = methanol. In addition, the analysis was conducted by changing the concentration of B solution as described below.
B liquid concentration: 60% (0 min) → 65% (25 min) → 100% (35 min)
・Mobile phase flow rate: 0.3ml/min
・Detection method: Q-Tof
・Ionization method: ESI (+, -) method ・Ion Source: Voltage (+) 2.0kV, (-) 1.5kV, temperature 120°C
・Sampling Cone: Voltage 30V, gas flow 50L/h
・Desolvation Gas: Temperature 500℃, gas flow 1000L/h

2. Analytical conditions for the production example of tetracarboxylic dianhydride represented by the above general formula (1)

[1] Infrared absorption spectrum The infrared absorption spectrum of the tetracarboxylic dianhydride of the present invention was measured by the KBr plate method using a Fourier transform infrared spectrophotometer (FT-IR4100, manufactured by JASCO Corporation).

[2] NMR measurement
¹ H-NMR and ¹³ C-NMR were recorded on a JEOL-ECP400 spectrometer using tetramethylsilane as internal standard and DMSO- _d6 as solvent.

[3] Melting point of tetracarboxylic dianhydride Melting point was measured in a nitrogen atmosphere at a temperature increase rate of 5° C./min using a differential scanning calorimeter (DSC3100) manufactured by Netsch Japan.

[4] Elemental analysis In order to confirm that the diamine of the present invention has sufficiently high purity, elemental analysis was performed using an organic trace element analyzer (JM10) manufactured by J Science Lab Co., Ltd. Ta.

3. Analysis conditions for production examples of polyamic acid represented by the above general formula (2) and polyimide represented by the above general formula (3)

[1] Infrared absorption spectrum The infrared absorption spectrum of the polyimide thin film of the present invention was measured using a transmission method using a Fourier transform infrared spectrophotometer (FT-IR4100, manufactured by JASCO Corporation).

[2] Intrinsic viscosity Polyimide powder was dissolved in N,N-dimethylacetamide (DMAc), or polyamic acid varnish was diluted to make a 0.5% by weight DMAc solution, and reduced at 30°C using an Ostwald viscometer. The viscosity was measured. This value can be substantially regarded as the intrinsic viscosity, and the higher the value, the higher the molecular weight.

[3] Glass transition temperature (T _g )
By dynamic viscoelasticity measurement using a thermomechanical analyzer (TMA4000) manufactured by Necchi Japan, the peak temperature of the loss energy curve at a frequency of 0.1 Hz and a heating rate of 5°C/min was used to determine the The glass transition temperature ( _Tg ) was determined. The higher the _Tg , the higher the physical heat resistance.

[4] Coefficient of linear thermal expansion (CTE)
According to thermomechanical analysis using a thermomechanical analyzer (TMA4000) manufactured by Necchi Japan, the elongation of the test piece at a load of 0.5 g/film thickness of 1 μm and a temperature increase rate of 5°C/min was found to be within the range of 100 to 200°C. The CTE of the polyimide film (thickness: about 20 μm) was determined as the average value of . The lower this value is, the better the thermal dimensional stability is.

[5] 5% weight loss temperature (T _d ⁵ )
Using ^a thermogravimetric _analyzer ( _{TG - DTA2000} ⁾ manufactured by Netch Japan, polyimide The temperature at which the initial weight of the film (film thickness: about 20 μm) decreased by 5% was measured. The higher the value of T _d ⁵ , the higher the thermal stability.

[6] Solvent solubility For 10 mg of the obtained polyimide powder, put 1 mL of organic solvent (solid content concentration approximately 1% by weight) into a sample tube, stir for 5 minutes using a test tube mixer, and visually check the state of dissolution. did. The evaluation criteria are as follows.
++: Dissolved at room temperature +: Dissolved by heating -: Insoluble

4. Synthesis example of bisphenol represented by the above formula (4)

<Manufacture example 1>

Into a glass reaction vessel equipped with a stirrer, a condenser and a thermometer, 45.00 g (0.250 mol) of 9-fluorenone, 123.74 g (1.124 mol) of hydroquinone, 41.25 g (0.375 mol) of resorcinol, p - 4.75 g (0.025 mol) of toluenesulfonic acid and 450.00 g of p-xylene were charged, and the temperature was raised to 110°C. After stirring at the same temperature for 3 hours, the reaction solution was analyzed by HPLC, and no peak of 9-fluorenone was detected.

Subsequently, ion-exchanged water was added to the obtained reaction solution and the mixture was cooled to 70° C. At the same temperature, a 24% by weight aqueous sodium hydroxide solution was added to neutralize it, and then 45.00 g of p-xylene was added. Thereafter, the reaction solution was heated to 86°C and filtered at 86°C to remove inorganic salts. After filtration, p-xylene and isopropyl acetate were added to the filtrate, stirred and allowed to stand, and the aqueous phase was separated and removed. Next, the organic phase was washed with ion-exchanged water at 80° C., and then the organic phase was concentrated to dryness to obtain 69.87 g of pale orange crystals. When the obtained crystals were analyzed by HPLC, the content of bisphenol represented by the above formula (4) was 54.9%.

Next, 15.0 g of the obtained crystals were purified with a silica gel column (developing solvent: chloroform:ethyl acetate = 12/1) to obtain crystals with a bisphenol content of 93.9% represented by the above formula (4). 2.59 g and 4.93 g of crystals having a bisphenol content of 88.7% represented by the above formula (4) were obtained.

Among the crystals obtained in the above example, the crystals with a content (purity) of 93.9% were subjected to ¹ H-NMR, ¹³ C-NMR and LC-MS analysis. The results of each analysis are shown below.

¹ H-NMR (DMSO-d ₆ , 400 MHz, TMS) δ (ppm): 9.20 (bs, 2H), 7.93 (d, 4H, J = 7.6Hz), 7.36 (dt, 4H , J=7.2Hz, 0.8Hz), 7.23 (dt, 4H, J=8.0Hz, 1.2Hz), 7.05 (d, 2H, J=8.8Hz), 7.04( d, 4H, J = 8.0Hz), 6.58 (dd, 2H, J = 8.8Hz, 2.8Hz), 6.55 (d, 2H, J = 2.0Hz), 6.21 (dd , 2H, J=8.4Hz, 2.8Hz), 6.00 (d, 2H, J=8.8Hz), 5.64 (d, 2H, J=2.8Hz).

¹³ C-NMR (DMSO-d ₆ , 400 MHz, TMS) δ (ppm): 157.6, 154.7, 152.7, 151.8, 143.8, 139.1, 128.4, 128.1 , 127.8, 127.6, 125.3, 125.1, 120.3, 117.4, 115.6, 113.8, 112.3, 111.3, 102.5, 53.6.

Mass spectrum value (MH ^- ): 363.10

5. Synthesis example of tetracarboxylic dianhydride

<Example 1>
1.833 g (5.0 mmol) of bisphenol represented by the above formula (4), produced by the same method as described in Production Example 1, was dissolved in 27 mL of dehydrated acetone, and 2.43 mL of pyridine ( 30.0 mmol) was added thereto, and the solution was sealed with a septum cap to obtain Solution A. Next, in another three-necked flask, 3.161 g (15.0 mmol) of trimellitic anhydride chloride was dissolved in 9.4 mL of dehydrated acetone, and the solution was sealed with a septum cap to obtain a B solution. Solution B was cooled in an ice bath, and while stirring with a magnetic stirrer, Solution A was slowly added dropwise to Solution B using a syringe. After the dropwise addition was completed, the mixture was stirred under cooling for several hours, and further stirred at room temperature for 12 hours. After the reaction was completed, acetone was distilled off using an evaporator. The precipitate was washed with toluene and then with water until no chloride ions were detected. By vacuum drying this at 200° C. for 12 hours, 2.41 g (yield: 72%) of a pale yellow crude product was obtained.

Of the obtained crude product, 1.53g was recrystallized using a mixed solution of toluene and acetic anhydride (volume ratio 25:2) and vacuum-dried at 200°C for 12 hours to obtain 1.05g of yellow powder. (Total yield: 50%) was obtained. The analysis results of this powder are shown below.

-Melting point: 294°C (DSC).
・FT-IR spectrum (KBr, cm ^-1 ): 3066 (aromatic C-H stretching vibration), 1863/1780 (acid anhydride C=O stretching vibration), 1736 (ester C=O stretching vibration), 1488 ( substituted phenyl group), 1223 (ester + xanthene group C-O-C stretching vibration).
¹ H-NMR spectrum (400 MHz, DMSO-d ₆ , δ, ppm): 8.63-8.59 (m, 2H, phthalic anhydride 3,6-proton), 8.48-8.45 (m, 2H, phthalic anhydride 3',6'-proton), 8.28 (d, 1H,, J=7.9Hz, phthalic anhydride 5-proton), 8.16 (d, 1H,, J=7. 8Hz, phthalic anhydride 5'-proton), 8.02 (d, 2H, J = 7.6Hz, fluorene group 4,8-proton), 7.50-7.45 (m, 4H, fluorene group 3, 7-proton + 4,7-proton of xanthene group), 7.37-7.31 (m, 3H, fluorene group 2,6-proton + 8-proton of xanthene group), 6.92 (dd, 1H, J =8.6, 2.3Hz, xanthene group 2-proton), 6.37-6.35 (m, 2H, xanthene group 1,5-proton).
- Elemental analysis (molecular weight 712.63): Estimated value (%) C: 72.47, H: 2.83, analytical value C: 72.44, H: 3.16.

From the above analysis results, it was confirmed that the above powder was the desired tetracarboxylic dianhydride of the present invention, represented by the following formula (5).

6. Production examples of polyamic acid and polyimide and property evaluation of polyimide films

<Example 2>
Place 1 mmol of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in a well-dried airtight reaction vessel, and add N,N-dimethylacetamide (hereinafter sometimes referred to as DMAc) that has been sufficiently dehydrated with molecular sieves 4A. ) was added and dissolved. To this solution, 1 mmol of tetracarboxylic dianhydride represented by the above formula (5), which was produced by the same method as in Example 1, was added, and the polymerization reaction was started at an initial total solute concentration of 30% by weight. After the reaction started, a homogeneous and viscous polyamic acid solution was obtained by stirring at room temperature for 72 hours. Note that during the reaction, the solution viscosity became too high, so DMAc was added as appropriate, and the final solute concentration was 21%.

After the reaction was completed, the intrinsic viscosity of the polyamic acid was measured using an Ostwald viscometer in DMAc at 30°C at a concentration of 0.5% by weight. The intrinsic viscosity was 1.48 dL/g, indicating that the polyamic acid had a sufficiently high molecular weight. I confirmed that there is.

Subsequently, the polyamic acid solution obtained as described above was diluted with DMAc, and a chemical imidization agent containing 5 times the theoretical dehydration amount of acetic anhydride (volume ratio of acetic anhydride/pyridine: 7/3) was added dropwise. A chemical imidization reaction was carried out by stirring at room temperature for 24 hours to obtain a polyimide solution containing the polyimide of the present invention. The obtained polyimide solution was diluted with DMAc and dropped into a large amount of methanol to precipitate polyimide powder, and the polyimide powder was isolated by filtering and drying the powder. When this polyimide powder was dissolved in deuterated dimethyl sulfoxide and the ¹ H-NMR spectrum was measured, it was confirmed that the chemical imidization reaction was completed. Further, the intrinsic viscosity of the obtained polyimide powder was measured and found to be 1.85 dL/g.

By redissolving this polyimide powder in cyclopentanone (CPN), a polyimide solution with a solid content concentration of 15% by weight was obtained. The obtained polyimide solution was applied to a glass substrate, dried for 2 hours at 60°C in a hot air dryer, and dried together with the substrate at 200°C in vacuum for 1 hour to form a polyimide film. It was peeled off and heat treated at 250°C for 1 hour.

The glass transition temperature, CTE, and 5% weight loss temperature of the obtained polyimide film were measured under the conditions described above. The results are shown below.
・Glass transition temperature (Tg): 268°C
・CTE: 25.4ppm/K
- 5% weight loss temperature; in nitrogen: 499°C, in air: 475°C.

The reason why the CTE showed a low value of 25.4 ppm/K is that the main chain structure of the polyimide of the present invention is rigid and has high linearity. This is thought to be due to the fact that the film was significantly oriented in a direction parallel to the film surface.

Table 1 shows the solvent solubility of the obtained polyimide. Furthermore, the infrared absorption spectrum of the polyimide film is shown in FIG.

<Example 3>
Polyamic acid was polymerized according to the method described in Example 2, except that 4,4'-oxydianiline (ODA) was used instead of TFMB as the diamine, followed by chemical imidization, varnish formation, film formation, and film formation. Physical properties were evaluated. The solvent solubility of the obtained polyimide is shown in Table 1, and the physical property values are shown in Table 2.

<Example 4>
Instead of using the tetracarboxylic dianhydride represented by the above formula (5) alone as the tetracarboxylic dianhydride, the tetracarboxylic dianhydride represented by the above formula (5) and other tetra Except that 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropanoic dianhydride (6FDA) was copolymerized at a molar ratio of 1:1 as the carboxylic dianhydride. According to the method described in Example 2, polyamic acid was polymerized, chemically imidized, varnished, film-formed, and characterized. The solvent solubility of the obtained polyimide is shown in Table 1, and the physical property values are shown in Table 2.

<Comparative example 1>
After carrying out the same procedure as in Example 3 except for using pyromellitic anhydride (PMDA) as the tetracarboxylic dianhydride component, a polyimide film was produced through a thermal imidization step, and the film properties were evaluated. The obtained polyimide was insoluble in any solvent and did not have solution processability.

<Comparative example 2>
As the tetracarboxylic dianhydride component, the following formula (8):

で表されるテトラカルボン酸二無水物を用いる以外は実施例２に準じて重合、化学イミド化及び製膜し、膜物性評価を行った。得られたポリイミドの溶媒溶解性を表１に、各物性値を表２に記載する。

Polymerization, chemical imidization, and film formation were performed according to Example 2 except that the tetracarboxylic dianhydride represented by was used, and the physical properties of the film were evaluated. The solvent solubility of the obtained polyimide is shown in Table 1, and the physical property values are shown in Table 2.

<Comparative example 3>
Polymerization, chemical imidization, and film formation were performed according to Example 3, except that the tetracarboxylic dianhydride represented by the above formula (8) was used as the tetracarboxylic dianhydride component, and the film physical properties were evaluated. The solvent solubility of the obtained polyimide is shown in Table 1, and the physical property values are shown in Table 2.

Abbreviations of solvents in Table 1 above DMF: N,N-dimethylformamide DMAc: N,N-dimethylacetamide NMP: N-methylpyrrolidone GBL: γ-butyrolactone THF: Tetrahydrofuran CPN: Cyclopentanone

Claims (6)

The following formula ( 5 ):
Tetracarboxylic dianhydride represented by The following formula ( 5-1 ):
Or the following formula ( 5-2 ):
A polyamic acid having a repeating unit represented by : The following formula ( 5-3 ):
Or the following formula ( 5-4 ):
A polyimide having a repeating unit represented by A polyimide solution containing the polyimide according to claim 3 in a solid content concentration of 5% by weight or more. A polyimide film comprising the polyimide according to claim 3. The polyimide according to claim 3, or the polyimide film according to claim 5, having a glass transition temperature of 250°C or higher.

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