WO2016148150A1 - Novel tetracarboxylic dianhydride, and polyimide and polyimide copolymer obtained from said acid dianhydride - Google Patents

Abstract

A tetracarboxylic dianhydride represented by formula (1), and a polyimide or polyimide copolymer produced from this tetracarboxylic dianhydride, are used. This makes it possible to provide a polyimide and a polyimide copolymer having exceptional solvent solubility (solvent processability) and heat resistance, as well as a polyimide film containing the same.

Description

Novel tetracarboxylic dianhydride, and polyimide and polyimide copolymer obtained from the acid dianhydride

The present invention relates to a novel tetracarboxylic dianhydride having a spiro structure, and a polyimide and a polyimide copolymer obtained from the tetracarboxylic dianhydride.

Polyimide that can withstand high temperatures of solder mounting temperature (260 ° C.) or more as a plastic material for microelectronics is widely used as an insulating layer for semiconductor elements and flexible printed wiring boards. However, most of the polyimides with high heat resistance are poor in workability, and are mostly processed from a polyimide precursor, that is, a polyamic acid soluble in a solvent (Non-patent Document 1).

In order to form a polyimide from a polyamic acid, a high temperature of 300 ° C. or higher is required, so the use may be limited depending on the imidization temperature. Further, when a polyimide film is produced from a polyamic acid film, depending on the thermal imidization conditions, there is a concern that film breakage due to curing shrinkage or voids are generated in the film, and imidation reaction control is very difficult. Furthermore, there is a drawback that a high temperature furnace of 300 ° C. or higher is required at the time of imidization, and the production cost is increased.

Therefore, a polyimide that is soluble in a solvent (solvent-soluble polyimide) and a thermoplastic polyimide that can be melt-molded have been recently developed in the state where imidization has already been completed, and the processability is improved over conventional polyimides. Most of such polyimides have a polymer main chain such as a siloxane chain or an ether bond bent in the polyimide main chain to introduce a bond that easily undergoes intramolecular rotation, or a bulky substituent on the side chain. To improve the workability by inhibiting the aggregation of polymer chains or reducing the concentration of imide groups in the main chain (Non-patent Documents 2 and 3). However, such molecular design almost reduces the inherent heat resistance of polyimide with almost no exception. Accordingly, few polyimides have both heat resistance of 260 ° C. or higher, particularly 290 ° C. or higher, and high solvent solubility.

Polyimides obtained from aromatic tetracarboxylic dianhydrides (electron-accepting) and aromatic diamines (electron-donating) are used for dipole-dipole interactions between carbonyl groups of imide rings and charge transfer interactions between molecules. The action strengthens the cohesive force between the polymer chains and restricts the molecular motion, and the glass transition temperature is much higher than that of general-purpose resins. The charge transfer interaction also occurs in the molecule, and most of the polyimide film has a very low light transmittance in the visible region due to the charge transfer interaction between the molecule and the molecule (Non-patent Document 4). In addition, in a polyimide having a linear and rigid chemical structure, the linear thermal expansion coefficient (CTE) of the film may be as low as that of an inorganic material, and the heat resistant film exhibits excellent thermal dimensional stability against heat. It becomes a material (Non-Patent Document 5).

In general, a polyimide film is a polyimide precursor soluble in a solvent, that is, a polyamic acid solution (varnish) is cast and dried on a support to form a polyamic acid film, which is then subjected to a dehydration ring-closing reaction at a high temperature ( It is manufactured by thermal imidization (Non-patent Document 1). In general, during thermal imidization, it proceeds with the elimination of water as a by-product and residual solvent in the film, so a strong shrinkage force is generated along the film surface direction, and the film is fixed to a support. If it is, it will be apparently stretched. In a polyimide system having a linear and rigid chemical structure, the polyimide chain is highly oriented along the film surface by such a stretching action (Non-Patent Documents 6 and 7). Due to this action, the polyimide film exhibits low thermal expansion, that is, excellent thermal dimensional stability. Currently, high dimensional stability polyimide is widely used as an insulating layer for semiconductor elements and flexible printed wiring boards. However, polyimides with excellent heat resistance and thermal dimensional stability are usually insoluble and infusible, so they have poor workability, and are processed into a film at the stage of a solvent-soluble precursor (polyamic acid). A process for thermal imidization of this must be selected. Since a high temperature of 300 ° C. or higher is required in the thermal imidization step, such a high-temperature film forming process is disadvantageous in applications (particularly optical devices) where a non-colored transparent polyimide film is required. Therefore, as described above, a solution / thermoprocessable polyimide is required. However, if a solution / thermoprocessable polyimide is to be obtained by a known method, there is almost no exception and the inherent heat resistance of the polyimide film is reduced and linear heat is applied. This leads to a significant increase in expansion coefficient (deterioration of thermal dimensional stability) (Non-patent Document 7).

Therefore, in principle, it is extremely difficult to obtain a polyimide film having high heat resistance and low thermal expansion by simply applying and drying a polyimide varnish (without a thermal imidization step). Under such circumstances, there is no known method for obtaining a polyimide that retains uncolored transparency for application to various optical uses in addition to solution processability, heat resistance, and low thermal expansion.

Prog. Polym. Sci. 16, 561 (1991). Polym. Eng. Sci. 29, 1413 (1989). Polym. 39, 1945 (1998). Prog. Polym. Sci. , 26, 259 (2001). J. et al. Appl. Polym. Sci. 31, 101 (1986). Polym. 30, 1170 (1989). Macromolecules, 29, 7897 (1996).

INDUSTRIAL APPLICABILITY The present invention provides a tetracarboxylic dianhydride for providing a resin having both excellent solvent solubility (solution processability) and high heat resistance, and excellent solution processability synthesized from the tetracarboxylic dianhydride. An object is to provide a polyimide, a solution containing the polyimide, and a film having high heat resistance obtained from the polyimide and the polyimide solution. The present invention also provides a polyimide film obtained by applying and drying a polyimide copolymer and a solution containing the polyimide copolymer, and simultaneously having high heat resistance, low linear thermal expansion coefficient and high transparency. With the goal.

As a result of intensive studies to solve the above problems, the present inventors have obtained a polyimide having excellent solution processability from a tetracarboxylic dianhydride represented by the following formula (1), and a solution containing the polyimide From the above, it was found that a polyimide film having a heat resistance of 260 ° C. or higher was obtained, and the present invention was completed.

The present invention is as follows.

[1]
Following formula (1):

で表されるテトラカルボン酸二無水物。

Tetracarboxylic dianhydride represented by

[2]
The following general formula (2):

（式（２）中、Ｘは２価の芳香族または脂肪族基を表す。）
で表される繰り返し単位を有するポリイミド。

(In formula (2), X represents a divalent aromatic or aliphatic group.)
The polyimide which has a repeating unit represented by these.

The present inventors also have a copolymer having a specific structure among polyimides containing a structure derived from the tetracarboxylic dianhydride represented by the above formula (1), that is, represented by the following formula (5). The polyimide copolymer having the repeating unit and the repeating unit represented by the following general formula (6) gives a stable polyimide solution at room temperature, and is coated and dried, so that it has high heat resistance and low linear heat. The inventors have found that a polyimide film having an expansion coefficient and high transparency can be obtained at the same time, and completed the present invention.

The present invention is as follows.

[3]
Following formula (5):

で表される繰り返し単位、及び、
下記一般式（６）：

A repeating unit represented by:
The following general formula (6):

（式中、Ｙは下記式（７）～（１２）からなる群より選ばれる少なくとも１種の４価の芳香族基を表す。）で表される繰り返し単位を有するポリイミド共重合体。

(Wherein Y represents at least one tetravalent aromatic group selected from the group consisting of the following formulas (7) to (12)), and a polyimide copolymer having a repeating unit represented by:

According to the present invention, a polyimide having both high heat resistance (high glass transition temperature) and solvent solubility, which has been extremely difficult to achieve with the prior art, a polyimide film produced from a solution containing the polyimide, and the polyimide are provided. It is possible to provide a tetracarboxylic dianhydride having a fluorene skeleton and a spiro skeleton.

Furthermore, by selecting a copolymer having a specific structure from among the polyimides, it is possible to provide a polyimide film having both low heat expansion and high heat resistance and high transparency.

4 is a chart of FT-IR measured in Example 2. 6 is a chart of FT-IR measured in Example 3. 6 is a chart of FT-IR measured in Example 4. 6 is a chart of FT-IR measured in Example 5. 6 is a chart of FT-IR measured in Example 6. 10 is a chart of FT-IR measured in Example 8. 10 is a chart of FT-IR measured in Example 10. 14 is a chart of FT-IR measured in Example 12. 18 is a chart of FT-IR measured in Example 14. 18 is a chart of FT-IR measured in Example 15.

<Tetracarboxylic dianhydride>
The tetracarboxylic dianhydride of the present invention has a structure represented by the following formula (1).

　本発明の式（１）で表されるテトラカルボン酸二無水物の合成方法は、特に限定されないが、例えば、下記式（３）で表されるジオール、即ちスピロ［フルオレン－９，９’－（２’，７’－ジヒドロキシキサンテン）］または、そのジアセテート体と下記式（４）で表されるトリメリット酸またはその誘導体から公知のエステル化反応によって合成される。

The method for synthesizing the tetracarboxylic dianhydride represented by the formula (1) of the present invention is not particularly limited. For example, a diol represented by the following formula (3), that is, spiro [fluorene-9,9′- (2 ′, 7′-dihydroxyxanthene)] or a diacetate thereof and trimellitic acid represented by the following formula (4) or a derivative thereof by a known esterification reaction.

　トリメリット酸誘導体としては、無水トリメリット酸、無水トリメリット酸ハライド等が挙げられる。

Examples of trimellitic acid derivatives include trimellitic anhydride and trimellitic anhydride halide.

<Polyimide>
The structural characteristics of the tetracarboxylic dianhydride represented by the formula (1) according to the present invention include a spiro structure in which the xanthene structure and the fluorene structure are orthogonal to each other, and the phthalic anhydride moiety is converted to the xanthene structure via an ester bond. It is at the point where it joins.

The polyimide represented by the following formula (2) according to the present invention uses the tetracarboxylic dianhydride represented by the above formula (1) as a raw material to obtain a useful polyimide having the above-mentioned specific physical properties. be able to. The production method is not particularly limited. For example, the tetracarboxylic dianhydride represented by the above formula (1) is reacted with an aromatic or aliphatic compound having a divalent nucleophilic reactive functional group. After obtaining a polyimide precursor having a repeating unit represented by the following formula (2), a tetracarboxylic acid represented by the above formula (1) in a two-step synthesis method through a process of imidization or in a high boiling point solvent There is a one-step synthesis method in which an dianhydride and an aromatic or aliphatic compound having a divalent nucleophilic reactive functional group are reacted at 150 to 220 ° C. with stirring.

The polyimide of the present invention has a structure represented by the following formula (2).

（式（２）中、Ｘは２価の芳香族または脂肪族基を表す。）
　上記式（２）中、Ｘで表される２価の芳香族または脂肪族基は、後述する上記式（１）で表されるテトラカルボン酸二無水物と反応させる、２価の求核反応性官能基を有する芳香族または脂肪族化合物の骨格構造を表す。なお、本発明における２価の求核反応性官能基としてはアミノ基、イソシアナート基等が例示される。

(In formula (2), X represents a divalent aromatic or aliphatic group.)
In the above formula (2), a divalent aromatic or aliphatic group represented by X is reacted with a tetracarboxylic dianhydride represented by the above formula (1) described later. Represents a skeleton structure of an aromatic or aliphatic compound having a functional group. In addition, an amino group, an isocyanate group, etc. are illustrated as a bivalent nucleophilic reactive functional group in this invention.

Specific examples of aromatic or aliphatic compounds having a divalent nucleophilic reactive functional group include, for example, p-phenylenediamine, m-phenylenediamine, 4,4′-bis (4-aminophenoxy) biphenyl as diamines. 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, benzidine, 3,3'-dihydroxybenzidine, 3, 3'-dimethoxybenzidine, o-tolidine, m-tolidine, 4,4'-diamino-2,2'-bis (to Fluoromethyl) biphenyl, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4'-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diamino Benzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzanilide, 4-aminophenyl-4'-aminobenzoate, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene 2,4-diaminodurene, 4,4'-diaminodi Phenylmethane, 4,4'-methylenebis (2-methylaniline), 4,4'-methylenebis (2-ethylaniline), 4,4'-methylenebis (2,6-dimethylaniline), 4,4'-methylenebis Aromatic diamines such as (2,6-diethylaniline), 4,4′-methylenebis (cyclohexylamine), isophoronediamine, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 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-aminocyclohexane) Sil) propane, 2,2-bis (4-aminocyclohexyl) hexafluoropropane and other alicyclic diamines, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1, Examples thereof include chain aliphatic diamines such as 6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, and diaminosiloxane. The diisocyanates include 1,5-phenylene diisocyanate, 1,3-diisocyanatobenzene, 3,3′-dichloro-4,4′-diisocyanatobiphenyl, and 4,4′-diisocyanate. -3,3'-dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, 2,2-bis (4-isocyanatophenyl) hexafluoropropane Aromatic diisocyanates such as dicyclomethane, alicyclic diisocyanates such as dicyclohexylmethane 4,4′-diisocyanate, and chain aliphatic diisocyanates such as hexamethylene diisocyanate. Two or more of these may be used in combination.

Aromatic or aliphatic tetracarboxylic acid other than the tetracarboxylic dianhydride represented by the above formula (1) within a range that does not significantly impair the polymerization reactivity and the characteristics of the polyimide when polymerizing the polyimide according to the present invention. An anhydride can be used in combination as a copolymerization component. Examples of aromatic tetracarboxylic dianhydrides that can be used in this case include pyromellitic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4. '-Biphenyltetracarboxylic 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, 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′-biphenyl Sulfonetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropanoic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) propanoic dianhydride Thing etc. are mentioned. The aliphatic tetracarboxylic dianhydride is not particularly limited. For example, as the alicyclic one, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic Acid dianhydride, 5- (dioxotetrahydrofuryl-3-methyl-3-cyclohexene-1,2-dicarboxylic acid 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 Examples thereof include cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, etc. Two or more of these may be used in combination.

As the solvent for synthesizing the polyimide or polyamic acid according to the present invention, aprotic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like are preferable. However, any solvent can be used without any problem as long as the raw material, the polyimide precursor to be produced, and the imidized polyimide are dissolved and do not react with the raw material or the product. It is not limited to.

Specifically, for example, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε -Ester solvents such as caprolactone, α-methyl-γ-butyrolactone, butyl acetate, ethyl acetate and isobutyl acetate, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as diethylene glycol dimethyl ether, triethylene glycol and triethylene glycol dimethyl ether Phenol solvents such as phenol, m-cresol, p-cresol, o-cresol, 3-chlorophenol, 4-chlorophenol, cyclopentanone, cyclohexanone, acetone, methyl Ketone solvents such as ethyl ketone, diisobutyl ketone and methyl isobutyl ketone, ether solvents such as tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethoxyethane 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, ethyl cellosolve acetate, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, Petroleum naphtha solvents can be used, and two or more of these may be used in combination.

The method for synthesizing the tetracarboxylic dianhydride represented by the formula (1) of the present invention is not particularly limited, and a known esterification reaction can be appropriately used. Specifically, for example, a solution in which trimellitic anhydride chloride is dissolved in a dehydrated aprotic solvent and a diol of formula (3) and a deoxidizing agent are dissolved in the same solvent, using a mechanical stirrer or the like, Add in the temperature range of −78 ° C. to 0 ° C., preferably −30 ° C. to −5 ° C. and stir for 0.5 to 48 hours, preferably 1 to 24 hours. Thereafter, the reaction solution is heated to 0 to 100 ° C., preferably 10 to 50 ° C., and stirred for 0.5 to 48 hours, preferably 1 to 24 hours to complete the esterification. Subsequently, the product is isolated from the solution containing the product, washed as appropriate, and dried at 20 to 220 ° C., more preferably at 50 to 200 ° C. with a vacuum dryer or the like, and is represented by the formula (1) of the present invention. Tetracarboxylic dianhydride can be obtained. When the purity of the tetracarboxylic dianhydride represented by the formula (1) of the present invention is low, it can be appropriately purified by a known method such as a sublimation method or a recrystallization method.

The method for synthesizing the polyimide represented by the above formula (2) of the present invention and the solution containing the polyimide is not particularly limited, and a known imidization reaction can be appropriately used.

Specifically, for example, it can be synthesized by the following one-step method. When the divalent nucleophilic reactive functional group is an isocyanate group, an aromatic or aliphatic diisocyanate is dissolved in a solvent, and the tetraisocyanate represented by the formula (1) is equimolar with the diisocyanate group. Add the carboxylic acid dianhydride powder gradually or in portions and use a mechanical stirrer or the like in the temperature range of −20 to 100 ° C., more preferably 0 to 50 ° C. for 0.5 to 168 hours, The solution containing the polyimide represented by the above formula (2) is preferably obtained by stirring for 1 to 72 hours.

Further, when the divalent nucleophilic reactive functional group is an amino group, an aromatic or aliphatic diamine is dissolved in a high boiling point solvent, and the tetracarboxylic acid represented by the formula (1) is equimolar with the diamine. After the dianhydride powder is added gradually or in portions, an azeotropic agent such as toluene is added, and an inert gas is introduced at 150 to 220 ° C., more preferably at 160 to 190 ° C. For 0.5 to 10 hours, more preferably 1 to 5 hours, and imidation can be achieved by removing the water produced during imidization out of the system together with the azeotropic agent. A solution containing the polyimide represented by (2) can be obtained. In addition, when removing the water and the azeotropic agent which are by-products of the imidation reaction, the inside of the reaction vessel can be reduced in pressure, and the solid content concentration can be increased by this step.

Further, the polyimide represented by the above formula (2) of the present invention and the solution containing the polyimide can also be synthesized using the following two-step method. When the divalent nucleophilic reactive functional group is an amino group, first, as a first step, an aromatic or aliphatic diamine is dissolved in a solvent, and this solution is represented by the formula (1) equimolar with the diamine. Tetracarboxylic dianhydride powder is added gradually or in portions, and a temperature of 0 to 100 ° C., more preferably 5 to 50 ° C. for 0.5 to 168 hours, using a mechanical stirrer or the like, More preferably, the polyamic acid solution which is a polyimide precursor is obtained by stirring for 1 to 96 hours. In this case, the solid concentration is preferably the maximum concentration at which the solution becomes uniform and can be stirred in order to maximize the molecular weight of the polyamic acid. That is, the solid content concentration is 1 to 50% by weight, more preferably 5 to 40% by weight. With such a solid content concentration, the degree of polymerization of the produced polyamic acid is sufficiently high. In addition, when an aliphatic diamine is used, salt formation often occurs at the initial stage of polymerization and the polymerization is hindered, but in order to increase the degree of polymerization as much as possible while suppressing salt formation, the solid content concentration during the polymerization is It is preferable to manage within a suitable concentration range.

Next, a method for imidizing the polyimide precursor obtained above, that is, polyamic acid, will be described as the second stage. In order to obtain the polyimide of this invention, well-known methods, such as the high temperature solution imidation method thermally dehydrated and closed and the chemical imidation method using a dehydrating agent, can be used suitably.

Specifically, for example, when applying a high temperature solution imidization method, a solvent that can be used in producing the above-described polyamic acid to the polyamic acid solution obtained by the above method synthesized in a high boiling point solvent, In particular, the same solvent as that used in the preparation of the polyamic acid is added to obtain an appropriate solution viscosity that is easy to stir. Further, an azeotropic agent such as toluene is added, and 150 to 220 ° C., more preferably while introducing an inert gas. , By stirring at 160 to 190 ° C. using a mechanical stirrer for 0.5 to 10 hours, more preferably 1 to 5 hours, and easily removing water generated during imidization together with the azeotropic agent from the system. A solution containing polyimide represented by the above formula (2) can be obtained by imidization and simply returning the temperature to room temperature. In addition, when removing water and an azeotropic agent which are by-products at the time of imidation, it is possible to reduce the pressure in the reaction vessel, thereby increasing the solid content concentration.

In addition, when applying the chemical imidization method, a solvent that can be used for producing the above-described polyamic acid to the polyamic acid solution obtained by the above-described method, in particular, the same solvent as that used for producing the polyamic acid is used. In addition, the solution viscosity is set to an appropriate level that is easy to stir, and while stirring with a mechanical stirrer or the like, an organic acid anhydride and a dehydrating cyclization agent (chemical imidization agent) composed of a tertiary amine as a basic catalyst are dropped. The imidization can be completed chemically by stirring at -100 ° C, preferably 10-50 ° C, for 1-72 hours. Although it does not specifically limit as an organic acid anhydride which can be used in that case, An acetic anhydride, propionic anhydride, etc. are mentioned. Acetic anhydride is preferably used because of easy handling and separation of the reagent. As the basic catalyst, pyridine, triethylamine, quinoline and the like can be used, but pyridine is preferably used because of easy handling and separation of the reagent, but is not limited thereto. The amount of the organic acid anhydride in the chemical imidizing agent is in the range of 1 to 20 times mol, more preferably 1 to 10 times mol of the theoretical dehydration amount of the polyamic acid. The amount of the basic catalyst is in the range of 0.1 to 2 moles, more preferably in the range of 0.1 to 1 moles, relative to the amount of the organic acid anhydride.

In the reaction solution obtained by the chemical imidization method, by-products (hereinafter referred to as impurities) such as bases, unreacted chemical imidization agents, and organic acids are mixed. Polyimide may be isolated and purified. A known method can be used for purification. For example, as the simplest method, after dripping in a large amount of poor solvent while stirring the imidized reaction solution to precipitate polyimide, the polyimide powder is recovered and repeatedly washed until impurities are removed, A method of obtaining polyimide powder by drying under reduced pressure can be applied. At this time, the solvent that can be used is not particularly limited as long as it can precipitate polyimide, efficiently remove impurities, and can be easily dried. For example, water, alcohols such as methanol, ethanol, and isopropanol are preferable. These may be used in combination. When the solid content concentration of the polyimide solution when dropped in a poor solvent is too high, the precipitated polyimide becomes agglomerates and impurities remain in the coarse particles, or the obtained polyimide powder is used as a solvent. It may take a long time to redissolve. On the other hand, if the concentration of the polyimide solution is too thin, a large amount of poor solvent is required, which may increase the environmental load and increase the manufacturing cost due to waste solvent treatment. Therefore, the concentration (solid content concentration) of the polyimide solution when dripped in the poor solvent is 20% by weight or less, more preferably 10% by weight or less. The amount of the poor solvent used at this time can be appropriately adjusted by those skilled in the art depending on the type of solvent and polyimide in the polyimide solution. The polyimide powder deposited as described above is collected, and the residual solvent is removed by vacuum drying or hot air drying. 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 a temperature of 30 to 150 ° C. for 3 to 24 hours.

The polyimide powder represented by the above formula (2) thus obtained needs to be dissolved in a solvent in order to obtain a polyimide solution. The solvent that can be used can be appropriately selected according to the intended use and processing conditions of the polyamic acid solution. Specifically, for example, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, ester solvents such as butyl acetate, ethyl acetate and isobutyl acetate, carbonate solvents such as ethylene carbonate and propylene carbonate, glycols such as diethylene glycol dimethyl ether, triethylene glycol and triethylene glycol dimethyl ether Solvent, phenol solvents such as phenol, m-cresol, p-cresol, o-cresol, 3-chlorophenol, 4-chlorophenol, cyclopentanone, cyclohexanone, acetone, methyl Ketone solvents such as ethyl ketone, diisobutyl ketone and methyl isobutyl ketone, ether solvents such as tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethoxyethane 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, ethyl cellosolve acetate, butanol, ethanol, xylene, toluene, chlorobenzene, terpene, mineral spirit, Petroleum naphtha solvents can also be used, and two or more of these may be used in combination.

In particular, when continuous coating is performed for a long time, if the solvent in the polyimide solution absorbs moisture in the air and the polyimide may be deposited, a low solvent such as triethylene glycol dimethyl ether, γ-butyrolactone, or cyclopentanone may be used. It is preferable to use a hygroscopic solvent. Also, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like, which are hygroscopic solvents, can be combined with the above low hygroscopic solvent to suppress the precipitation of polyimide. You can also. The polyimide powder can be dissolved in air or in an inert gas at a temperature ranging from room temperature to the boiling point of the solvent over 1 to 48 hours to form a polyimide solution.

The intrinsic viscosity of the polyimide represented by the formula (2) of the present invention is preferably 0.1 dL / g or more, more preferably 0.2 dL / g or more in consideration of the film toughness of the polyimide film. If the intrinsic viscosity is less than 0.1 dL / g, the toughness of the polyimide film cannot be ensured, and the film may be brittle.

The molecular weight of the polyimide of the present invention is preferably 5000 or more, more preferably 10,000 or more in terms of weight average molecular weight from the viewpoints of moldability and handleability. The molecular weight of the polyimide can be based on the viscosity of the polyimide solution.

Next, a polyimide solution containing a polyimide represented by the above formula (2) of the present invention and a method for producing a polyimide film obtained by molding the polyimide solution will be described. The polyimide solid content concentration in the polyimide solution can be appropriately selected according to the use of the solution. For example, in the case of a film, it depends on the molecular weight of the polyimide, the production method, and the desired film thickness. The solid concentration is preferably 5% by weight or more, preferably 5% by weight to 40% by weight. If the solid content concentration is too low, it may be difficult to form a film having a sufficient film thickness. Conversely, if the solid content concentration is high, the solution viscosity may be too high and coating may be difficult. In addition, the solid content concentration of the polyimide in this invention represents the content of the solid content (mainly polyimide represented by the said Formula (2)) remaining after removing a solvent from a polyimide solution by a usual method.

In addition, the polyimide solution containing the polyimide represented by the above formula (2) of the present invention may include a release agent, a filler, a silane coupling agent, a crosslinking agent, a terminal sealing agent, an antioxidant, Additives such as foaming agents and leveling agents can be added.

Although the form which manufactures a film using the said polyimide solution is demonstrated, a manufacturing method will not be specifically limited if a self-supporting film | membrane with film | membrane toughness can be produced.

Specifically, for example, there is a known method of applying a polyimide solution on a support such as a glass substrate using a doctor blade or the like and then drying to prepare a polyimide film. Alternatively, it can be applied onto a metal foil such as copper foil using a known method, for example, a doctor blade, and then dried to obtain a polyimide / metal foil laminated film, which can withstand high temperature processes during solder mounting. It can also be used for copper-clad laminates for flexible printed wiring boards. Furthermore, if the polyimide solution is applied to an insulating material for a semiconductor or a flexible wiring board, the insulating layer can be easily formed by coating directly on the device and drying the solvent.

The polyimide film produced as described above usually has a glass transition temperature of 260 ° C. or higher, particularly 290 ° C. or higher, so that it is particularly suitably used as a heat resistant film. For example, as an insulating material for semiconductors and flexible wiring boards When used, since the glass transition temperature of the insulating layer is 260 ° C. or higher, it can sufficiently withstand 260 ° C., which is a lead-free solder mounting temperature, and is therefore preferably used as an insulating material.

<Polyimide copolymer>
The polyimide copolymer of the present invention (hereinafter sometimes referred to as the polyimide of the present invention) has a repeating unit represented by the following formula (5) and a repeating unit represented by the following general formula (6). In the formula (6), Y represents at least one tetravalent aromatic group selected from the group consisting of the following formulas (7) to (12).

　本発明のポリイミド共重合体は、下記式（１３）で表されるテトラカルボン酸二無水物及び下記式（１４）～（１９）からなる群より選ばれる少なくとも１種のテトラカルボン酸二無水物と下記式（２０）で表されるジアミンから製造される。

The polyimide copolymer of the present invention includes at least one tetracarboxylic dianhydride selected from the group consisting of a tetracarboxylic dianhydride represented by the following formula (13) and the following formulas (14) to (19): And a diamine represented by the following formula (20).

　本発明のポリイミド共重合体の製造方法として例えば、上記式（１３）で表されるテトラカルボン酸二無水物及び上記式（１４）～（１９）からなる群より選ばれる少なくとも１種のテトラカルボン酸二無水物と上記式（２０）で表されるジアミンとを反応させて本発明のポリイミド前駆体（ポリアミド酸）を得た後、イミド化する工程を経る二段階合成法、または高沸点溶媒中、上記式（１３）で表されるテトラカルボン酸二無水物及び上記式（１４）～（１９）からなる群より選ばれる少なくとも１種のテトラカルボン酸二無水物と上記式（２０）で表されるジアミンとを１５０～２２０℃で撹拌しながら反応させる一段階合成法がある。

Examples of the method for producing the polyimide copolymer of the present invention include at least one tetracarboxylic dianhydride represented by the above formula (13) and at least one tetracarboxylic acid selected from the group consisting of the above formulas (14) to (19). A two-step synthesis method or a high-boiling solvent that undergoes an imidization step after reacting an acid dianhydride with a diamine represented by the above formula (20) to obtain a polyimide precursor (polyamide acid) of the present invention. Among them, at least one tetracarboxylic dianhydride selected from the group consisting of the tetracarboxylic dianhydride represented by the above formula (13) and the above formulas (14) to (19) and the above formula (20) There is a one-step synthesis method in which the represented diamine is reacted with stirring at 150 to 220 ° C.

Other diamines can be used in combination with the diamine represented by the above formula (20) as long as the properties of the polyimide according to the present invention are not significantly impaired. Usable diamines include, for example, p-phenylenediamine, m-phenylenediamine, 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, benzidine, 3,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine, o-tolidine, m-tolidine, 1,4-bis ( 4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3- (3-aminophenoxy) benzene, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 2,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminobenzophenone, 3,3′-diaminobenzophenone, 4,4′-diaminobenzanilide, 4-aminophenyl-4′-aminobenzoate, 2,4-diamino Toluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4,4'-diaminodiphenylmethane, 4,4'-methylenebis (2-methylaniline), 4,4'-methylenebis (2-ethylaniline), 4,4'-methylenebis (2,6-dimethylaniline), aromatic diamines such as 4,4′-methylenebis (2,6-diethylaniline), 4,4′-methylenebis (cyclohexylamine), isophoronediamine, trans-1,4-diamino Cyclohexane, cis-1,4-diaminocyclohexane, 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 Alicyclic diamines such as 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1, Chains such as tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, diaminosiloxane And an aliphatic diamine. Two or more of these may be used in combination.

As long as the characteristics of the polyimide copolymer according to the present invention are not significantly impaired, other tetracarboxylic dianhydrides can be used in combination with the tetracarboxylic dianhydrides represented by the above formulas (13) to (19). is there. Examples of tetracarboxylic dianhydrides that can be used include 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 1, 4,5,8-naphthalene tetracarboxylic dianhydride, 3,4,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2,3,2 ′, 3′-benzophenone tetracarboxylic dianhydride, 3,4,3 ′, 4′-biphenyl ether tetracarboxylic dianhydride, 3,4,2 ′, 3′-biphenyl ether tetra Carboxylic dianhydride, 2,3,2 ′, 3′-biphenyl ether tetracarboxylic dianhydride, 3,4,3 ′, 4′-biphenylsulfone tetracarboxylic dianhydride, 3,4,2 ′ , 3 ' Biphenylsulfonetetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenylsulfonetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) hexafluoropropanoic acid dianhydride Aromatic tetracarboxylic dianhydrides such as 2,2′-bis (3,4-dicarboxyphenyl) propanoic dianhydride, and 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 Aliphatic tetracarboxylic dianhydrides such as dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydrides, 1,2,3,4-cyclopentanetetracarboxylic dianhydrides, and the like. Two or more of these may be used in combination.

As the solvent for synthesizing the polyimide copolymer or polyamic acid according to the present invention, the solvents described above with respect to the polyimide according to the present invention can be used.

The method for producing the tetracarboxylic dianhydride represented by the above formulas (13) to (19) used in the present invention is not particularly limited. For example, the above formula (13) having an ester group in its structure and the tetracarboxylic dianhydride represented by the above formulas (17) to (19) are produced by appropriately using a known esterification reaction. . Specifically, a solution in which trimellitic anhydride chloride is dissolved in a dehydrated aprotic solvent, and a solution in which a diol of the following formulas (21) to (24) and a deoxidizer are dissolved in a dehydrated aprotic solvent are used. After each preparation, these solutions are used in a temperature range of −78 ° C. to 0 ° C., preferably at −30 ° C. to −5 ° C. for 0.5 to 48 hours, preferably 1 to 24 hours using a mechanical stirrer or the like. Mix slowly. Thereafter, the reaction solution is heated to 0 to 100 ° C., preferably 10 to 50 ° C., and stirred for 0.5 to 24 hours, preferably 1 to 12 hours to complete esterification, and then formed from a solution containing the product. The product is isolated, washed as appropriate, and dried at 100 to 220 ° C., more preferably 120 to 200 ° C. with a vacuum dryer or the like, so that the formula (13) and the formula (17) used in the present invention are used. A tetracarboxylic dianhydride represented by (19) can be obtained. When the purity of the tetracarboxylic dianhydride represented by the above formula (13) and the above formulas (17) to (19) of the present invention is low, it is appropriately purified by a known method such as a sublimation method or a recrystallization method. it can.

　本発明のポリイミド共重合体及び該ポリイミド共重合体を含む溶液を合成する方法は特に限定されず、公知のイミド化反応を適宜用いることができる。なお、後述するイミド化反応においては、上記式（１３）で表されるテトラカルボン酸二無水物と上記式（１４）～（１９）からなる群より選ばれる少なくとも１種のテトラカルボン酸二無水物とを併用する必要があるが、その混合比率は通常、上記式（１３）で表されるテトラカルボン酸二無水物１モルに対し上記式（１４）～（１９）からなる群より選ばれる少なくとも１種のテトラカルボン酸二無水物を通常１～９９ｍｏｌ％、好ましくは２～７０ｍｏｌ％使用する。混合比率を適宜調整することにより、本発明のポリイミド共重合体中の上記式（５）で表される繰り返し単位と上記式（６）で表される繰り返し単位の含有率を調整することができる。

The method for synthesizing the polyimide copolymer of the present invention and the solution containing the polyimide copolymer is not particularly limited, and a known imidization reaction can be appropriately used. In the imidization reaction described later, at least one tetracarboxylic dianhydride selected from the group consisting of the tetracarboxylic dianhydride represented by the above formula (13) and the above formulas (14) to (19) is used. The mixing ratio is usually selected from the group consisting of the above formulas (14) to (19) with respect to 1 mol of tetracarboxylic dianhydride represented by the above formula (13). At least one tetracarboxylic dianhydride is usually used in an amount of 1 to 99 mol%, preferably 2 to 70 mol%. By appropriately adjusting the mixing ratio, the content of the repeating unit represented by the above formula (5) and the repeating unit represented by the above formula (6) in the polyimide copolymer of the present invention can be adjusted. .

Specifically, for example, it can be synthesized by the following one-step synthesis method. A diamine represented by the above formula (20) is dissolved in a high boiling point solvent, and a tetracarboxylic dianhydride represented by the above formula (13) and the group consisting of the above formulas (14) to (19) are dissolved in this solution. After adding powder gradually or divided so that the total tetracarboxylic dianhydride amount of at least one selected tetracarboxylic dianhydride is equimolar with diamine, an azeotropic agent such as toluene is added. The mixture is stirred at 150 to 220 ° C., more preferably 160 to 190 ° C. with a mechanical stirrer for 0.5 to 10 hours, more preferably 1 to 5 hours while introducing an inert gas. It can be imidized by removing water to be removed from the system together with the azeotropic agent, and a polyimide solution containing the polyimide copolymer of the present invention can be obtained simply by returning to room temperature. In addition, when removing the water and the azeotropic agent which are by-products of the imidation reaction, the inside of the reaction vessel can be reduced in pressure, and the solid content concentration can be increased by this step. The solvent used at this time is not particularly limited as long as the polyimide copolymer is not precipitated.

Further, the polyimide copolymer of the present invention and the solution containing the polyimide copolymer can also be synthesized using the following two-step synthesis method. First, as a first step, a diamine represented by the above formula (20) is dissolved in a solvent, and a tetracarboxylic dianhydride represented by the above formula (13) and the above formulas (14) to ( 19) After adding the powder gradually or divided so that the total amount of tetracarboxylic dianhydride of at least one tetracarboxylic dianhydride selected from the group consisting of 19) is equimolar with diamine, mechanical stirrer The polyamic acid as the polyimide precursor is obtained by stirring at a temperature in the range of 0 to 100 ° C., more preferably 5 to 50 ° C. for 0.5 to 168 hours, more preferably 1 to 96 hours. It is done. In this case, the solid concentration is preferably the maximum concentration at which the solution becomes uniform and can be stirred in order to maximize the molecular weight of the polyamic acid. That is, the solid content concentration is 1 to 50% by weight, more preferably 5 to 40% by weight. With such a solid content concentration, the degree of polymerization of the produced polyamic acid is sufficiently high. In addition, when an aliphatic diamine is used, salt formation often occurs at the initial stage of polymerization and the polymerization is hindered, but in order to increase the degree of polymerization as much as possible while suppressing salt formation, the solid content concentration during the polymerization is It is preferable to manage within a suitable concentration range.

As the second step, the polyimide precursor obtained above, that is, the method of imidizing the polyamic acid is as described above for the polyimide according to the present invention.

The polyimide copolymer powder thus obtained needs to be dissolved in a solvent in order to obtain a polyimide solution containing the polyimide copolymer of the present invention. Usable solvents include those described above with respect to the polyimide according to the present invention. Two or more of these may be mixed and used.

In particular, in the case of continuous coating over a long period of time, the solvent in the polyimide solution absorbs moisture in the air and the polyimide copolymer may be precipitated, as described above for the polyimide according to the present invention. .

The content of the repeating unit represented by the above formula (5) and the repeating unit represented by the above formula (6) in the polyimide copolymer of the present invention is usually 1 to 99 mol%, and maintains low linear thermal expansion. Therefore, the content is preferably 2 to 70 mol%.

The intrinsic viscosity of the polyimide copolymer of the present invention is as described above for the polyimide according to the present invention. In addition, the intrinsic viscosity in this invention represents the value measured by the method mentioned later.

The molecular weight of the polyimide copolymer of the present invention is as described above for the polyimide according to the present invention.

Next, a polyimide solution containing the polyimide copolymer of the present invention and a method for producing a polyimide film obtained by applying and drying the solution on a support will be described. The solid content concentration of the polyimide solution containing the polyimide copolymer of the present invention can be appropriately selected according to the use of the solution. For example, when it is set as a film, although depending on the molecular weight of the polyimide copolymer, the production method, and the desired film thickness, the solid content concentration is preferably 5% by weight or more. If the solid content concentration is too low, it may be difficult to form a film having a sufficient film thickness. Conversely, if the solid content concentration is high, the solution viscosity may be too high and coating may be difficult. In addition, the solid content concentration of the polyimide copolymer in the present invention represents the content of the solid content (mainly polyimide represented by the above formula (6)) remaining after removing the solvent from the polyimide solution by a conventional method.

The additives that can be added to the polyimide solution containing the polyimide copolymer of the present invention are as described above with respect to the polyimide according to the present invention.

The form of producing the polyimide film of the present invention using the polyimide solution containing the polyimide copolymer of the present invention is as described above for the polyimide according to the present invention.

Since the polyimide film of the present invention produced as described above usually has a glass transition temperature of 260 ° C. or higher, for example, insulation for semiconductors and flexible wiring boards that can sufficiently withstand the lead-free solder mounting temperature of 260 ° C. It is suitably used as a material.

The polyimide film of the present invention produced using the polyimide solution containing the polyimide copolymer of the present invention is characterized by high light transmittance and low linear thermal expansion, that is, usually the light transmittance at a wavelength of 400 nm is 30% or more, Moreover, since the linear thermal expansion coefficient is 40 ppm / K or less, it is excellent in transparency and thermal dimensional stability, so that it can be suitably used for various optical applications and optical devices.

The present invention can also be expressed as follows.

[4]
The polyimide copolymer according to [3], wherein the content of the repeating unit represented by the formula (5) is in the range of 2 to 70 mol% with respect to all repeating units in the polyimide copolymer.

[5]
A polyimide solution comprising the polyimide according to [2] or the polyimide copolymer according to [3] or [4] in a solid content concentration of 5% by weight or more.

[6]
A polyimide film comprising the polyimide according to [2], or the polyimide copolymer according to [3] or [4].

[7]
The heat resistant film containing the polyimide as described in [2], or the polyimide copolymer as described in [3] or [4] whose glass transition temperature is 260 degreeC or more.

[8]
[3] or [4] polyimide film having the following characteristics (A), (B) and (C):
(A) The light transmittance at a wavelength of 400 nm is 30% or more;
(B) the coefficient of linear thermal expansion is 40 ppm / K or less;
(C) Glass transition temperature (Tg) is 260 ° C. or higher.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The physical property values in the following examples were measured by the following methods.

(Evaluation methods)
<Infrared absorption spectrum>
Using a Fourier transform infrared spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation), the infrared absorption spectrum of tetracarboxylic dianhydride was measured by the KBr method. Moreover, about the infrared absorption spectrum of polyimide, after preparing the polyimide solution, it casted on the glass substrate, dried for 30 minutes at 100 degreeC, and measured the polyimide thin film sample (about 5 micrometers thickness) peeled from the glass substrate.

< ¹ H-NMR spectrum>
Using Fourier transform nuclear magnetic resonance JNM-ECP400 (manufactured by JEOL), ¹ H-NMR spectra of tetracarboxylic dianhydride and chemically imidized polyimide powder in deuterated dimethyl sulfoxide were measured. Tetramethylsilane was used as the standard substance.

<Differential scanning calorimetry (melting point)>
The melting point of tetracarboxylic dianhydride was measured at a heating rate of 5 ° C./min in a nitrogen atmosphere using a differential scanning calorimeter DSC3100 (Netch Japan). The higher the melting point and the sharper the melting peak, the higher the purity.

<Intrinsic viscosity>
The reduced viscosity of a 0.5 wt% polyimide precursor solution or polyimide solution was measured at 30 ° C. using an Ostwald viscometer. This value was regarded as the intrinsic viscosity.

<Solubility test of polyimide powder in organic solvent>
To 0.1 g of polyimide powder, 9.9 g of organic solvent (solid content concentration: 1% by weight) was put in a sample tube, stirred for 5 minutes using a test tube mixer, and the dissolved state was visually confirmed. As a solvent, chloroform (CF), acetone, tetrahydrofuran (THF), 1,4-dioxane (DOX), ethyl acetate, cyclopentanone (CPN), cyclohexanone (CHN), N, N-dimethylformamide (DMF), N , N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), m-cresol, dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), triethylene glycol dimethyl ether (Tri-GL) were used. The evaluation results are ++ when dissolved at room temperature, + when dissolved by heating and maintaining uniformity after being allowed to cool to room temperature, ± when swollen / partially dissolved, and − Is displayed.

<Linear thermal expansion coefficient: CTE and glass transition temperature: Tg>
The glass transition temperature of the polyimide film is 5 ° C / min with TMA4000 manufactured by Netch Japan Co., Ltd. (sample size width 5 mm, length 15 mm) and the load (static load) is film thickness (μm) × 0.5 g. Temporarily raised to 150 ° C (first temperature rise), then cooled to 20 ° C, further raised at 5 ° C / min (second temperature rise), and from the TMA curve at the second temperature rise Obtained from tangent method. The linear thermal expansion coefficient was determined as an average value between 100 and 200 ° C.

<Transmissivity of polyimide membrane: _T400 >
Using a UV-visible spectrophotometer V-530 (manufactured by JASCO Corp.), the light transmittance (T%) of the polyimide film at a wavelength of 200 to 800 nm was measured. A light transmittance of 400 nm was obtained as an index of transparency, and the transparency was evaluated.

<Yellowness (Yellowness Index): YI>
Using a UV-visible spectrophotometer V-530 (manufactured by JASCO Corp.), the light transmittance (T%) of the polyimide film at a wavelength of 380 to 780 nm was determined according to JISK77373 by the VWCT-615 color diagnostic program (manufactured by JASCO Corp.). The yellowness (YI) was calculated based on this.

<Total light transmittance and haze>
Using Haze Meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.), the total light transmittance of the polyimide film based on JISK7361 and the haze (turbidity) based on JISK7136 were determined.

<Synthesis Example 1> (Synthesis of tetracarboxylic dianhydride)
Synthesis of tetracarboxylic dianhydride containing no spiro structure as a comparative example.

8.4228 g (40.0 mmol) of trimellitic anhydride chloride was placed in an eggplant flask, dissolved in 36 mL of dehydrated N, N-dimethylformamide (DMF) at room temperature, and sealed with a septum to prepare solution A (solute concentration 20 wt%). ). Further, 3.7242 g (20.0 mmol) of 4,4′-biphenol was dissolved in 16 mL of dehydrated DMF at room temperature in a separate flask (solute concentration 20 wt%), and 120 mmol of pyridine was added thereto, followed by septum sealing to prepare solution B. . While cooling and stirring in an ice bath, solution B was gradually added dropwise to solution A with a syringe, and then stirred at room temperature for 12 hours. After completion of the reaction, the yellow precipitate was filtered off and washed with DMF and ion exchange water. Removal of pyridine hydrochloride was confirmed using an aqueous silver nitrate solution. The washed product was collected and vacuum dried at 180 ° C. for 12 hours. The obtained product was a yellow powder, the yield was 4.8465 g, and the yield was 38.5%. The resulting product, a Fourier transform infrared than spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation), 1861cm ^-1 and 1782cm ^-1 to acid anhydride group C = O stretching vibration, ester 1730 cm ^-1 The group C = O stretching vibration was confirmed. Further, as a result of proton NMR measurement using Fourier transform nuclear magnetic resonance JNM-ECP400 (manufactured by JEOL), DMSO-d ₆ , δ, ppm: 7.52 (d, 4H), 7.58 (d, 4H) ), 8.51 (d, 2H), 8.6 (m, 4H), 8.71-8.76 (m, 4H), confirming that it is the target tetracarboxylic dianhydride It was done. Further, when the melting point was measured with a differential scanning calorimeter DSC3100 (Netch Japan Co., Ltd.), a sharp melting peak was observed at 326 ° C., suggesting that this product is of high purity.

<Synthesis Example 2> (Synthesis of tetracarboxylic dianhydride)
Synthesis of tetracarboxylic dianhydride represented by formula (18).

8.4228 g (40.0 mmol) of trimellitic anhydride chloride was placed in an eggplant flask, dissolved in 36 mL of dehydrated N, N-dimethylformamide (DMF) at room temperature, and sealed with a septum to prepare solution A (solute concentration 20 wt%). ). Further, 3.7242 g (20.0 mmol) of 4,4′-biphenol was dissolved in 16 mL of dehydrated DMF at room temperature in a separate flask (solute concentration 20 wt%), and 120 mmol of pyridine was added thereto, followed by septum sealing to prepare solution B. . While cooling and stirring in an ice bath, solution B was gradually added dropwise to solution A with a syringe, and then stirred at room temperature for 12 hours. After completion of the reaction, the yellow precipitate was filtered off and washed with DMF and ion exchange water. Removal of pyridine hydrochloride was confirmed using an aqueous silver nitrate solution. The washed product was collected and vacuum dried at 180 ° C. for 12 hours. The obtained product was a yellow powder, the yield was 4.8465 g, and the yield was 38.5%. The obtained crude product was purified by recrystallization from γ-butyrolactone (GBL). The resulting product, a Fourier transform infrared than spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation), 1861cm ^-1 and 1782cm ^-1 to acid anhydride group C = O stretching vibration, ester 1730 cm ^-1 The group C = O stretching vibration was confirmed. Further, as a result of proton NMR measurement using Fourier transform nuclear magnetic resonance JNM-ECP400 (manufactured by JEOL), DMSO-d ₆ , δ, ppm: 7.52 (d, 4H), 7.58 (d, 4H) ), 8.51 (d, 2H), 8.6 (m, 4H), 8.71-8.76 (m, 4H), confirming that it is the target tetracarboxylic dianhydride It was done. Further, when the melting point was measured with a differential scanning calorimeter DSC3100 (Netch Japan Co., Ltd.), a sharp melting peak was observed at 326 ° C., suggesting that this product is of high purity.

<Synthesis Example 3> (Synthesis of tetracarboxylic dianhydride)
Synthesis of tetracarboxylic dianhydride represented by formula (19).

Trimellitic chloride 4.3185 (20 mmol) was placed in an eggplant flask, dissolved in 11 mL of dehydrated THF at room temperature, and sealed with a septum to prepare solution A (solute concentration 30 wt%). Further, 1.6019 g (10.0 mmol) of 2,6-dihydroxynaphthalene was dissolved in 4.2 mL of dehydrated THF at room temperature in a separate flask (solute concentration 30 wt%). Prepared. While cooling and stirring in an ice bath, solution B was gradually added dropwise to solution A with a syringe, and then stirred at room temperature for 12 hours. After completion of the reaction, the pale yellow precipitate was filtered off and washed with THF and ion exchange water. Removal of pyridine hydrochloride was confirmed using an aqueous silver nitrate solution. The washed product was collected and dried in vacuum at 160 ° C. for 12 hours. The obtained product was a yellow powder, the yield was 4.44853 g, and the yield was 88.2%. The obtained crude product was purified by recrystallization from γ-butyrolactone (GBL). The obtained product was obtained from a Fourier transform infrared spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation) at 1857 cm ⁻¹ and 1780 cm ⁻¹ with an acid anhydride group C═O stretching vibration and at 1732 cm ⁻¹ with an ester. The group C = O stretching vibration was confirmed. It was confirmed that it was the target tetracarboxylic dianhydride. Further, when the melting point was measured with a differential scanning calorimeter DSC3100 (Netch Japan Co., Ltd.), a sharp melting peak was shown at 301 ° C., suggesting that this product is of high purity.

<Example 1> (Synthesis of tetracarboxylic dianhydride)
Synthesis of tetracarboxylic dianhydride represented by the formula (1) of the present invention.

6.4617 g (30.687 mmol) of trimellitic anhydride chloride was placed in an eggplant flask, dissolved in 16.6 mL of dehydrated tetrahydrofuran (THF) at room temperature, and sealed with a septum to prepare solution A (solute concentration: 30.0% by weight) ). In a separate eggplant flask, 3.6439 g (10.57 mmol) of spiro [fluorene-9,9 ′-(2 ′, 7′-dihydroxyxanthene)] was dissolved in 47.1 mL of dehydrated THF at room temperature (solute concentration 8.0 wt. %), And 4.85 mL (60.0 mmol) of pyridine was added thereto, followed by septum sealing to prepare Solution B. While cooling and stirring in an ice bath, solution B was gradually added dropwise to solution A with a syringe and stirred for 1 hour, and then stirred at room temperature for 12 hours. After completion of the reaction, the white precipitate was filtered off and washed with THF and water. Removal of pyridine hydrochloride was confirmed by adding a silver nitrate aqueous solution to the washing solution and no white precipitate was observed. The washed product was collected and dried in vacuum at 100 ° C. for 12 hours. The obtained product was a white powder, the yield was 2.8336 g, and the yield was 39.8%.

The obtained product was obtained from Fourier transform infrared spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation) at 1856 cm ⁻¹ and 1781 cm ⁻¹ at acid anhydride group C═O stretching vibration absorption band, 1738 cm ^−1. The ester group C = O stretching vibration absorption band was confirmed. As a result of proton NMR measurement using Fourier transform nuclear magnetic resonance JNM-ECP400 (manufactured by JEOL), DMSO-d ₆ , δ, ppm; 8.62-8.51 (m, 4H), 8.27 (Dd, 2H, J = 8.0, 0.6 Hz), 8.15 (dd, 2H, J = 8.3, 1.8 Hz), 8.04 (d, 2H, J = 7.7 Hz), 7.49-7.46 (m, 4H), 7.32 (t, 2H, J = 7.5 Hz), 6.94 (dd, 2H, J = 8.7, 2.4 Hz), 6. 41 (d, 2H, J = 8.8 Hz), and the elemental analysis values are calculated C: 72.47%, H: 2.83%, measured C: 72.61%, H: 2. 97%
With the tetracarboxylic dianhydride represented by the formula (1) within 0.3%. Further, when the melting point was measured with a differential scanning calorimeter DSC3100 (Netch Japan Co., Ltd.), a sharp melting peak was observed at 332 ° C., suggesting that this product was of high purity.

<Example 2> (Polyamide acid polymerization; DABA system)
0.6818 g (3 mmol) of 4,4′-diaminobenzanilide (DABA) was dissolved in 6.57 g of dehydrated N, N-dimethylacetamide (DMAc). To this, 2.1378 g (3 mmol) of tetracarboxylic dianhydride powder represented by the formula (1) synthesized in Example 1 was slowly added and stirred at a solid content concentration of 30.0% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration: 15.0% by weight). The intrinsic viscosity of the obtained polyamic acid was 1.41 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.69 dL / g. Completion of imidation was confirmed by proton disappearance of the carboxy group in the polyamic acid and FT-IR by ¹ H-NMR (FIG. 1). Table 1 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in DMAc at room temperature to prepare a 15 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 300 ° C. for 1 hour. Table 2 shows the film physical properties of the obtained film.

<Example 3> (Polyamide acid polymerization; 4,4'-ODA system)
0.6007 g (3 mmol) of 4,4′-oxydianiline (4,4′-ODA) was dissolved in 6.39 g of dehydrated N, N-dimethylacetamide (DMAc). To this, 2.1378 g (3 mmol) of tetracarboxylic dianhydride powder represented by the formula (1) synthesized in Example 1 was slowly added and stirred at a solid content concentration of 30.0% by weight. While appropriately diluting with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 22.9% by weight). The intrinsic viscosity of the obtained polyamic acid was 0.96 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 1.17 dL / g. Completion of imidation was confirmed by disappearance of amide protons in the polyamic acid and 1 FT-IR by ¹ H-NMR (FIG. 2). Table 1 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in N-methyl-2-pyrrolidone (NMP) at room temperature to prepare a 15% by weight solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 80 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 300 ° C. for 1 hour. Table 2 shows the film physical properties of the obtained film.

<Example 4> (Polyamide acid polymerization; TFMB system)
0.9607 g (3 mmol) of 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl (TFMB) was dissolved in 7.2 g of dehydrated N, N-dimethylacetamide (DMAc). To this, 2.1378 g (3 mmol) of tetracarboxylic dianhydride powder represented by the formula (1) synthesized in Example 1 was slowly added and stirred at a solid content concentration of 30.0% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 23.6% by weight). The obtained polyamic acid had an intrinsic viscosity of 0.94 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.81 dL / g. Completion of imidization was confirmed by disappearance of amide protons in the polyamic acid and FT-IR by ¹ H-NMR (FIG. 3). Table 1 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in cyclopentanone (CPN) at room temperature to prepare a 23 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was dried again under reduced pressure at 280 ° C. for 1 hour. Table 2 shows the film physical properties of the obtained film.

<Example 5>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.3 g of dehydrated N, N-dimethylacetamide (DMAc). Here, 1.4965 g (2.1 mmol) of tetracarboxylic dianhydride powder represented by the formula (1), 0.2414 g (0.9 mmol) of tetracarboxylic dianhydride powder represented by the formula (16), and Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluting with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 22.9% by weight). The resulting polyamic acid had an intrinsic viscosity of 1.52 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.99 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 4). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in cyclopentanone (CPN) at room temperature to prepare a 12 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was dried again under reduced pressure at 280 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 6>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.0 g of dehydrated DMAc. A tetracarboxylic dianhydride powder represented by the formula (1) (1.2827 g, 1.8 mmol) and a tetracarboxylic dianhydride powder represented by the formula (16) (0.3218 g, 1.2 mmol) Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 24.6% by weight). The obtained polyamic acid had an intrinsic viscosity of 1.15 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 1.10 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 5). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in CPN at room temperature to prepare a 6 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was dried again under reduced pressure at 280 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 7>
The polyimide powder obtained in Example 6 was redissolved in DMAc at room temperature to prepare a 10% by weight solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was dried again under reduced pressure at 280 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 8>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.9 g of dehydrated DMAc. Here, 1.4965 g (2.1 mmol) of tetracarboxylic dianhydride powder represented by the formula (1), 0.4810 g (0.9 mmol) of tetracarboxylic dianhydride powder represented by the formula (18), and Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 21% by weight). The resulting polyamic acid had an intrinsic viscosity of 1.36 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.76 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 6). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in CPN at room temperature to prepare a 20 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 9>
The polyimide powder obtained in Example 8 was redissolved in DMAc at room temperature to prepare a 20% by weight solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 10>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.7 g of dehydrated DMAc. Here, 1.28827 g (1.8 mmol) of tetracarboxylic dianhydride powder represented by formula (1) and 0.6413 g (1.2 mmol) of tetracarboxylic dianhydride powder represented by formula (18) Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 25.1% by weight). The obtained polyamic acid had an intrinsic viscosity of 1.30 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.87 dL / g. The completion of imidization was confirmed by FT-IR (FIG. 7). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in CPN at room temperature to prepare a 20 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 11>
The polyimide powder obtained in Example 10 was redissolved in DMAc at room temperature to prepare a 20% by weight solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 12>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.6 g of dehydrated DMAc. Here, 1.0689 g (1.5 mmol) of tetracarboxylic dianhydride powder represented by formula (1), 0.8016 g (1.5 mmol) of tetracarboxylic dianhydride powder represented by formula (18), and Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration: 20.7% by weight). The obtained polyamic acid had an intrinsic viscosity of 1.23 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.79 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 8). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

<Example 13>
The polyimide powder obtained in Example 12 was redissolved in DMAc at room temperature to prepare a 12% by weight solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 14>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.6 g of dehydrated DMAc. Here, 1.2827 g (1.8 mmol) of tetracarboxylic dianhydride powder represented by formula (1) and 0.6101 g (1.2 mmol) of tetracarboxylic dianhydride powder represented by formula (19) Was slowly added and stirred at a solid concentration of 30% by weight. The mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor. The intrinsic viscosity of the obtained polyamic acid was 0.78 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.84 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 9). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

(Preparation of polyimide solution and preparation of polyimide film)
The obtained polyimide powder was redissolved in CPN at room temperature to prepare a 20 wt% solution. This polyimide solution was cast on a glass substrate and dried by a hot air dryer at 60 ° C. for 2 hours. Then, after drying at 200 degreeC under pressure reduction for 1 hour with the glass substrate, the polyimide film was peeled from the glass substrate after standing to cool to room temperature. This polyimide film was again dried under reduced pressure at 250 ° C. for 1 hour. Table 4 shows the film physical properties of the obtained film.

<Example 15>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.5 g of dehydrated DMAc. Here, 1.0689 g (1.5 mmol) of tetracarboxylic dianhydride powder represented by formula (1), 0.7626 g (1.5 mmol) of tetracarboxylic dianhydride powder represented by formula (19), and Was slowly added and stirred at a solid concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration 28.5% by weight). The resulting polyamic acid had an intrinsic viscosity of 0.83 dL / g.

(Polyimide synthesis by chemical imidization)
The obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. Stir for hours. The resulting polyimide solution was added to a large amount of deionized water to precipitate the desired product. The obtained precipitate was sufficiently washed with methanol and vacuum dried at 100 ° C. for 12 hours to obtain a polyimide powder. The intrinsic viscosity of the obtained polyimide was 0.74 dL / g. Completion of imidization was confirmed by FT-IR (FIG. 10). Table 3 shows the evaluation of the solubility of the obtained polyimide powder in each solvent.

<Comparative Example 1> (Polyamide acid polymerization; DABA system)
0.6818 g (3 mmol) of 4,4′-diaminobenzanilide (DABA) was dissolved in 20.6 g of dehydrated NMP. To this, 1.6033 g (3 mmol) of tetracarboxylic dianhydride powder containing no spiro structure synthesized in Synthesis Example 1 was slowly added and stirred at a solid content concentration of 10.0% by weight. The mixture was stirred at room temperature for 72 hours to obtain a viscous polyamic acid.

(Polyimide synthesis by chemical imidization)
After the obtained polyamic acid solution was diluted with dehydrated NMP to a solid content concentration of 8% by weight, a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. The reaction was interrupted. This is presumably because the polymer does not contain a spiro structure, so that its solubility in a solvent is insufficient and gelation occurs.

<Comparative Example 2> (Polyamide acid polymerization; 4,4′-ODA system)
0.6007 g (3 mmol) of 4,4′-oxydianiline (4,4′-ODA) was dissolved in 19.8 g of dehydrated NMP. To this, 1.6033 g (3 mmol) of tetracarboxylic dianhydride powder containing no spiro structure synthesized in Synthesis Example 1 was slowly added and stirred at a solid content concentration of 10.0% by weight. The mixture was stirred at room temperature for 72 hours to obtain a viscous polyamic acid.

(Polyimide synthesis by chemical imidization)
After the obtained polyamic acid solution was diluted with dehydrated NMP to a solid content concentration of 3% by weight, a mixed solution of 3.0627 g (30 mmol) of acetic anhydride and 1.1865 g (15 mmol) of pyridine was slowly added dropwise at room temperature. The reaction was interrupted. This is presumably because the polymer does not contain a spiro structure, so that its solubility in a solvent is insufficient and gelation occurs.

<Comparative Example 3> (Polyamide acid polymerization; TFMB system)
0.9607 g (3 mmol) of 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl (TFMB) was dissolved in 6.0 g of dehydrated N, N-dimethylacetamide (DMAc). To this, 1.6033 g (3 mmol) of tetracarboxylic dianhydride powder containing no spiro structure synthesized in Synthesis Example 1 was slowly added and stirred at a solid content concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration: 18.1% by weight). The obtained polyamic acid had an intrinsic viscosity of 2.26 dL / g.

(Polyimide synthesis by chemical imidization)
Half of the obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 1.5314 g (15 mmol) acetic anhydride and 0.5932 g (7.5 mmol) pyridine was slowly added dropwise at room temperature. As a result, the fluidity of the solution disappeared and gelation occurred, so the reaction was interrupted. This is presumably because the polymer does not contain a spiro structure, so that its solubility in a solvent is insufficient and gelation occurs.

<Comparative example 4>
(Polyamide acid polymerization)
0.9607 g (3 mmol) of the diamine represented by the formula (20) was dissolved in 6.0 g of dehydrated N, N-dimethylacetamide (DMAc). To this, 1.6033 g (3 mmol) of tetracarboxylic dianhydride powder represented by the formula (18) was slowly added and stirred at a solid content concentration of 30% by weight. While appropriately diluted with DMAc, the mixture was stirred at room temperature for 72 hours to obtain a polyamic acid as a polyimide precursor (solid content concentration: 18.1% by weight). The obtained polyamic acid had an intrinsic viscosity of 2.26 dL / g.

(Polyimide synthesis by chemical imidization)
Half of the obtained polyamic acid solution was diluted with dehydrated DMAc to a solid concentration of 8% by weight, and then a mixed solution of 1.5314 g (15 mmol) acetic anhydride and 0.5932 g (7.5 mmol) pyridine was slowly added dropwise at room temperature. As a result, the fluidity of the solution disappeared and gelation occurred, so the reaction was interrupted. This is presumably because the polymer does not contain a spiro structure, so that its solubility in a solvent is insufficient and gelation occurs.

　なお、上記表４中、かっこ内で記載した数値は各物性値を測定した際のポリイミドフィルムの膜厚である。

In Table 4, the numerical value described in parentheses is the film thickness of the polyimide film when each physical property value is measured.

Claims (8)

Following formula (1):

Tetracarboxylic dianhydride represented by The following general formula (2):

(In formula (2), X represents a divalent aromatic or aliphatic group.)
The polyimide which has a repeating unit represented by these. Following formula (5):

The repeating unit represented by the following general formula (6):

(Wherein Y represents at least one tetravalent aromatic group selected from the group consisting of the following formulas (7) to (12)).

The polyimide copolymer according to claim 3, wherein the content of the repeating unit represented by the above formula (5) is in the range of 2 to 70 mol% with respect to all repeating units in the polyimide copolymer. A polyimide solution containing the polyimide according to claim 2 or the polyimide copolymer according to claim 3 or 4 in a solid content concentration of 5% by weight or more. A polyimide film comprising the polyimide according to claim 2 or the polyimide copolymer according to claim 3 or 4. A heat-resistant film comprising the polyimide according to claim 2 or the polyimide copolymer according to claim 3 or 4 having a glass transition temperature of 260 ° C or higher. The polyimide film containing the polyimide copolymer according to claim 3 or 4 having the following characteristics (A), (B) and (C):
(A) The light transmittance at a wavelength of 400 nm is 30% or more;
(B) the coefficient of linear thermal expansion is 40 ppm / K or less;
(C) Glass transition temperature (Tg) is 260 ° C. or higher.

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