JP2016172726A - Novel tetracarboxylic dianhydride, and polyimide obtained from said acid dianhydride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tetracarboxylic dianhydride for giving a resin having exceptional solvent solubility (solvent processability) and high heat resistance, a polyimide synthesized from the tetracarboxylic dianhydride and having exceptional solvent processability and a solvent containing the polyimide, and a film obtained from the polyimide and polyimide solvent and having high heat resistance.SOLUTION: A tetracarboxylic dianhydride represented by formula (1), and a polyimide produced from the tetracarboxylic dianhydride, are used to solve the problem.SELECTED DRAWING: None

Description

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

As a plastic material for microelectronics, polyimide that can withstand a high temperature of solder mounting temperature (260 ° C.) or higher is widely used as an insulating layer such as a semiconductor element and a flexible printed wiring board. 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, and the use may be limited by 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.

  Thus, polyimides that are soluble in solvents (solvent-soluble polyimides) and thermoplastic polyimides that can be melt-molded have been developed in recent years, 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.

Prog. Polym. Sci. 16, 561 (1991). Polym. Eng. Sci. 29, 1413 (1989). Polym. 39, 1945 (1998).

The present invention relates to a tetracarboxylic dianhydride for providing a resin having both excellent solvent solubility (solution processability) and high heat resistance, and a polyimide excellent in solution processability synthesized from the tetracarboxylic dianhydride. It is another object of the present invention to provide a solution containing the polyimide, and a film having high heat resistance obtained from the polyimide and the polyimide solution.

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.

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

[4]
The polyimide film containing the polyimide as described in [2].

[5]
The heat resistant film containing the polyimide as described in [2] whose glass transition temperature is 260 degreeC or more.

According to the present invention, 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. A tetracarboxylic dianhydride having a fluorene skeleton and a spiro skeleton can be provided.

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.

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.

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。）

(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, and 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 (tri Fluoromethyl) biphenyl, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (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'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone 3,3′-diaminobenzophenone, 4,4′-diaminobenzanilide, 4-aminophenyl-4′-aminobenzoate, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,4-diaminoxylene, 2,4-diaminodurene, 4,4'-diaminodiph Phenylmethane, 4,4′-methylenebis (2-methylaniline), 4,4′-methylenebis (2-ethylaniline), 4,4′-methylenebis (2,6-dimethylaniline), 4,4′-methylenebis ( 2,6-diethylaniline), 4,4'-methylenebis (cyclohexylamine), isophoronediamine, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-cyclohexane Bis (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-aminocyclohex Alicyclic diamines such as propane and 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 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 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 together 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. Although it does not specifically limit as aliphatic tetracarboxylic dianhydride, For example, as an alicyclic thing, bicyclo [2.2.2] octo-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, dimethylsulfoxide 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 Phenolic solvents such as phenol, m-cresol, p-cresol, o-cresol, 3-chlorophenol, 4-chlorophenol, cyclopentanone, cyclohexanone, acetone, methyl Ketone solvents such as tilketone, diisobutylketone, methylisobutylketone, ether solvents such as tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethoxyethane, dibutylether, 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, The temperature is in the range of −78 ° C. to 0 ° C., preferably −30 ° C. to −5 ° C., and the mixture is stirred 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 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 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 dianhydride powder gradually or in portions, and use a mechanical stirrer or the like, at a temperature in the range of −20 to 100 ° C., more preferably at 0 to 50 ° C. for 0.5 to 168 hours, more Preferably, the solution containing the polyimide represented by the above formula (2) is 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 adding the dianhydride powder gradually or in portions, an azeotropic agent such as toluene is added, and an inert gas is introduced, and a mechanical stirrer or the like at 150 to 220 ° C., more preferably 160 to 190 ° C. The mixture is stirred for 0.5 to 10 hours, more preferably 1 to 5 hours, and the water generated during imidization can be imidized by removing it from 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.

Moreover, the polyimide represented by the above formula (2) of the present invention and the solution containing the polyimide can be synthesized also by using the following two-stage 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. The tetracarboxylic dianhydride powder is added gradually or in portions, and using a mechanical stirrer or the like, the temperature is in the range of 0 to 100 ° C., more preferably at 5 to 50 ° C. for 0.5 to 168 hours, 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 production 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 for 0.5 to 10 hours, more preferably 1 to 5 hours using a mechanical stirrer at 160 to 190 ° C., 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. Moreover, the quantity of a basic catalyst is the range of 0.1-2 times mole with respect to the amount of organic acid anhydrides, More preferably, it is the range of 0.1-1 times mole.

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 usable solvent can be appropriately selected in accordance with the use application and processing conditions of the polyimide 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 Solvents, 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, methyl isobutyl ketone, ether solvents such as tetrahydrofuran, 1,4-dioxane, dimethoxyethane, diethoxyethane, 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 applying continuously over a long period of time, if the solvent in the polyimide solution absorbs moisture in the air and the polyimide may be deposited, the low concentration of triethylene glycol dimethyl ether, γ-butyrolactone, cyclopentanone, etc. It is preferable to use a hygroscopic solvent. In addition, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like, which are hygroscopic solvents, suppress the precipitation of polyimide by combining with the low hygroscopic solvent. You can also. The polyimide powder can be dissolved in air or in an inert gas in a temperature range from room temperature to the boiling point of the solvent over 1 to 48 hours to form a polyimide solution.

In consideration of the film toughness of the polyimide film, 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. 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 and more preferably 10,000 or more in terms of weight average molecular weight from the viewpoint 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 content concentration is 5% by weight or more, preferably 5% 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 most preferable 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, for example, using a doctor blade, 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.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, it is not limited to these Examples. The physical property values in the following examples were measured by the following methods.

(Evaluation method)
<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 -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 even after being allowed to cool to room temperature, ± when swollen / partially dissolved, and − when insoluble. Is displayed.

<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.

<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.

<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) ). Spiro [fluorene-9,9 ′-(2 ′, 7′-dihydroxyxanthene)] 3.6439 g (10.507 mmol) was dissolved in 47.1 mL of dehydrated THF at room temperature (solute concentration 8.0 wt.) In another eggplant flask. %), 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 resulting product, a Fourier transform infrared spectrophotometer FT / IR-4100 from (manufactured by JASCO Corporation), 1856cm ^-1 and 1781cm ^-1 to acid anhydride group C = O stretching vibration absorption band, 1738 cm ^-1 The ester group C = O stretching vibration absorption band 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; 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 imidization was confirmed by ¹ H-NMR by proton disappearance of the carboxy group in the polyamic acid and FT-IR (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 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 imidation 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.

<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.

Claims (5)

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. A polyimide solution comprising the polyimide according to claim 2 in a solid content concentration of 5% by weight or more. A polyimide film comprising the polyimide according to claim 2. The heat resistance film containing the polyimide according to claim 2, which has a glass transition temperature of 260 ° C. or higher.

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