TWI820294B - Novel diamines, novel polyimides derived therefrom and molded body thereof - Google Patents

Abstract

An objective of the present invention is to provide a diamine compound to provide resins with both excellent solvent solubility (solution processability) and high heat resistance, a polyimide with excellent solution processability synthesized from the diamine compound, and a molded body having high heat resistance obtained from the polyimide. The above-mentioned objective can be solved by a diamine compound represented by the following general formula (1).

Description

Novel diamines, novel polyimides derived from the diamines and their shaped bodies

The present invention relates to a polyimide and a polyimide molded article. The polyimide is a polyimide derived from a novel diamine and has both excellent processability and high heat resistance. acyl imine. In addition to excellent solution processability, the polyimide of the present invention also has high heat resistance, so it can be used as an insulating material used in electronic devices such as flexible wiring substrates and semiconductors, as well as liquid crystal displays (LCDs), organic electrical excitation devices, etc. It is useful for plastic substrates used in optical (EL) displays, electronic paper, light emitting diode (LED) devices, solar cells, etc.

Polyimide, which can withstand high temperatures above the soldering mounting temperature (260°C), is widely used as an insulating material for semiconductor components and flexible printed wiring boards. However, many polyimide systems with high heat resistance lack processability, and in most cases, they are processed from polyamide precursors (for example, solvent-soluble polyamide acid) (Non-Patent Document 1) .

In order to form polyimide from a polyimide precursor (imidization), a high temperature of 300°C or above is required (thermal imidization), so the use may be limited due to the imidization temperature. . Also, from Ju When the imine precursor is used to produce a polyimide molded article, depending on the thermal imidization conditions, there may be breakage due to shrinkage associated with dehydration and ring closure, as well as detachment components produced during the imidization. However, there is a risk of defects (voids) occurring in the molded article, and it is very difficult to control the imidization reaction. Furthermore, there is a disadvantage that a high-temperature furnace required for imidization of 300° C. or higher is required, and the manufacturing cost also becomes high.

Therefore, in recent years, a polyimide (solvent-soluble polyimide) has been developed that is soluble in solvents in a state where imidization has been completed, and has improved processability compared to conventional polyimides. Most of such polyimides have bonds such as siloxane chains or ether bonds introduced into the polyimide main chain to bend the polymer main chain and facilitate intramolecular rotational motion, or in the side chains. Bulky substituents are placed into the polymer to hinder the aggregation of the polymer chain, or the concentration of acyl imine groups in the main chain is reduced to improve processability (Non-Patent Documents 2 and 3). However, such a molecular design significantly reduces the original heat resistance of polyimide. Therefore, it is difficult to synthesize a polyimide that has both heat resistance above 300°C and high solvent solubility.

[Prior technical literature]

[Non-patent literature]

Non-patent document 1: Prog. Polym. Sci., 16, 561(1991).

Non-patent document 2: Polym. Eng. Sci., 29, 1413(1989).

Non-patent document 3: J. Polym. Sci., Part A, Polym. Chem., 44, 6836 (2006).

An object of the present invention is to provide a diamine compound for obtaining a resin having both excellent solvent solubility (solution processability) and high heat resistance, and a polyimide excellent in solution processability synthesized from the diamine compound. , and a molded body with high heat resistance obtained from the polyimide.

As a result of intensive research in order to solve the above-mentioned problems, the present inventors found that a polyimide excellent in solution processability can be obtained from a diamine compound represented by the following general formula (1), and that the polyimide has Heat resistance above 300°C, and the present invention was completed.

The present invention is as follows.

1. A diamine compound represented by the following general formula (1),

(In the general formula, R ₁ and R ₂ are trifluoromethyl groups, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, a, b, c, and d each independently represent integers from 0 to 4, but the total of a and c and the total of b and d are each 4 or less.)

2. A diamine compound represented by the following general formula (2),

(In the general formula, R ₅ and R ₆ each independently represent a hydrogen atom or a trifluoromethyl group.)

3. A polyimide containing a structural unit represented by the following general formula (3),

(In the general formula, R ₁ and R ₂ are trifluoromethyl groups, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, a, b, c, and d each independently represent an integer from 0 to 4, and X represents a tetravalent aromatic and/or aliphatic group, but the total of a and c and the total of b and d are each 4 or less.)

4. A polyimide containing a structural unit represented by the following general formula (4),

(In the general formula, R ₅ and R ₆ each independently represent a hydrogen atom or a trifluoromethyl group, and X represents a tetravalent aromatic and/or aliphatic group.)

5. A polyimide solution comprising the polyimide described in item 3 or 4 and a solvent.

6. A polyimide formed body obtained from the polyimide solution described in item 5.

According to the present invention, it can be obtained by using a diamine compound with six methyl groups substituted on the central biphenyl group as a raw material: it has the characteristics that have been difficult in conventional technologies, that is, excellent solution processability and high Heat-resistant polyimide and its molded products.

Figure 1 is a diagram showing the infrared absorption spectrum of the polyimide film of Example 2.

Figure 2 is a diagram showing the infrared absorption spectrum of the polyimide film of Example 3.

Figure 3 is a diagram showing the infrared absorption spectrum of the polyimide film of Example 4.

Figure 4 is a diagram showing the infrared absorption spectrum of the polyimide film of Example 6.

The diamine compound of the present invention has a chemical structure represented by the following general formula (1).

(In the general formula, R ₁ and R ₂ are trifluoromethyl groups, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, a, b, c, and d each independently represent integers from 0 to 4. However, the total of a and c and the total of b and d are each 4 or less.)

In the general formula (1), a and b are preferably independently 0, 1 or 2, with 0 or 1 being more preferably, and 1 being even more preferably. Among them, it is better when a and b are a combination of 0 and 1, or when both are 1. In this case, the (trifluoromethyl) substitution position of R ₁ and R ₂ is preferably adjacent to the ether bond. position or meta-position, the ortho-position is better.

In the general formula (1), when either R ₃ or R ₄ is an alkyl group having 1 to 4 carbon atoms, it means a linear or branched alkyl group having 1 to 4 carbon atoms, specifically Examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl. Among them, an alkyl group having 1 or 2 carbon atoms is preferred. When either R ₃ or R ₄ is an alkoxy group having 1 to 4 carbon atoms, it means a linear or branched chain alkoxy group having 1 to 4 carbon atoms. Specific examples include methane. Oxygen, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy. Among them, an alkoxy group having 1 or 2 carbon atoms is preferred. In the general formula (1), preferred embodiments of R ₃ and R ₄ are methyl, ethyl, and methoxy, and among them, methyl is more preferred. The preferred values for c and d are independently 0, 1 or 2, with 0 or 1 being better, and 0 being even better.

In the general formula (1), the substitution position of the amine group is preferably meta-position or para-position relative to the ether bond, more preferably para-position.

Among the diamine compounds represented by the general formula (1), preferred are the diamine compounds represented by the following general formula (2).

(In the general formula, R ₅ and R ₆ each independently represent a hydrogen atom or a trifluoromethyl group.)

In the general formula (2), the substitution position of the amine group is preferably meta-position or para-position relative to the ether bond, with para-position being more preferred. In addition, when either or both R ₅ and R ₆ are trifluoromethyl, the substitution position is preferably ortho or meta with respect to the ether bond, more preferably ortho.

The chemical structure of the polyimide using the diamine compound represented by the general formula (1) is characterized by: 2,2', 3,3', 5,5 of the biphenyl groups are extended in the center through the ether bond. There are 6 methyl groups at the ' position. These methyl groups cause the dihedral angle of the extended biphenyl group to be greatly twisted (non-coplanarity) due to the steric hindrance effect, hindering the cohesion between polymer chains and improving the solubility in solvents. In addition, the steric hindrance effect also inhibits the intramolecular rotation around the ether bond, so it will increase the heat resistance of the polyimide inserted into this structure, that is, it will increase the glass transition temperature. Among them, when a trifluoromethyl group is introduced into both or only one of R ₅ and R ₆ in the general formula (2), the same stereoscopic effect is particularly contributed.

The present invention will be described in detail below.

The polyimide of the present invention is produced using a diamine compound represented by the following general formula (1).

<Production method of diamine compound>

The diamine compound represented by the above general formula (1) is as shown in the following reaction formula. Diol (5) (that is, 2,2',3,3',5,5'-hexamethyl- Biphenyl-4,4'-diol (hereinafter sometimes also referred to as HM44BP) and halogenated nitrobenzene represented by the following general formulas (6) and (7) are subjected to a known etherification reaction. The dinitrobody intermediate is produced into a diamine compound by a known reduction reaction.

(In the above reaction formula, R ₁ to R ₄ and a to d have the same meaning as in the general formula (1), and Y represents a halogen atom.)

Suitable examples of the halogenated nitrobenzene represented by the above general formulas (6) and (7), specifically, include 4-chloronitrobenzene and 4-fluoronitrobenzene whose chemical structures are shown below. , 2-chloro-5-nitrotrifluorotoluene, 2-fluoro-5-nitrotrifluorotoluene, 1-chloro-3-nitrobenzene, 3-fluoronitrobenzene, 5-chloro-2-nitrotrifluorotoluene Trifluorotoluene, 5-fluoro-2-nitrotrifluorotoluene, 2-chloro-5-nitrotoluene, 2-fluoro-5-nitromethyl Benzene, 2,5-dimethyl-4-chloronitrobenzene, 2,5-dimethyl-4-fluoronitrobenzene, 2-chloro-5-nitrobenzene, 2-fluoro-5- Nitroanisole, 2,3-dimethyl-4-chloronitrobenzene, 2,3-dimethyl-4-fluoronitrobenzene, etc. The halogenated nitrobenzene represented by the general formula (6) and the halogenated nitrobenzene represented by the general formula (7) may be the same.

Furthermore, diamine compounds synthesized from the above-mentioned suitable halogenated nitrobenzene compounds may specifically include those having the following chemical structural formulas.

The chemical structure of the diamine compound represented by the above-mentioned general formula (1), which is the raw material of the polyimide of the present invention, is characterized by the presence of six methyl substituents in the central biphenyl group. The face angle increases (makes it twist). This can improve the solubility in solvents and heat resistance.

Regarding the polyimide of the present invention, a diamine compound represented by the general formula (1) can be used as a raw material and reacted with an acid dianhydride to synthesize a polyimide containing a structural unit represented by the following general formula (3). Amine can be used to obtain a polyimide having excellent properties as described above.

(In the general formula, R ₁ and R ₂ are trifluoromethyl groups, R ₃ and R ₄ independently represent an alkyl group with 1 to 4 carbon atoms and an alkoxy group with 1 to 4 carbon atoms, a, b , c, and d each independently represent an integer from 0 to 4, and X represents a tetravalent aromatic and/or aliphatic group. However, the total of a and c and the total of b and d are each 4 or less.)

In the polyimide containing the structural unit represented by the general formula (3), the appropriate substitution positions of R ₁ to R ₄ , their substitution positions and the number of substituents a to d, and the substitution positions of the nitrogen atoms derived from the amino group The chemical structure is the same as that of the diamine compound represented by general formula (1).

Among the polyimides of the present invention, in particular, polyimides containing a structural unit represented by general formula (4) exhibit excellent effects of improving solubility in solvents and heat resistance.

(In the general formula, R ₅ and R ₆ each independently represent a hydrogen atom or a trifluoromethyl group, and X represents a tetravalent aromatic and/or aliphatic group.)

In the polyimide containing the structural unit represented by the general formula (4), the suitable chemical structure regarding R ₅ and R ₆ , their substitution positions and the substitution position of the nitrogen atom derived from the amine group is the same as that of the general formula The diamine compounds shown in (2) are the same.

The manufacturing method of polyimide is not particularly limited, but it can be manufactured through the following steps: making acid dianhydride (such as aromatic and/or aliphatic tetracarboxylic dianhydride) and the diamine containing the present invention The steps of reacting the diamines of the compound in an equimolar manner to obtain a polyamide precursor (polyamide acid) represented by the following general formula (8); and making the polyamide The precursor is subjected to the step of imidization.

(In the general formula, R ₁ to R ₄ and a to d have the same meaning as in the general formula (1).)

The aromatic and/or aliphatic tetracarboxylic dianhydride that can be used when polymerizing the polyimide precursor of the present invention is not particularly limited. Examples of the aromatic tetracarboxylic dianhydride include pyromellitic acid dianhydride. Anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, hydroquinone-bis(trimellitic anhydride), methylhydroquinone-bis(trimellitic anhydride), 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4 ,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-diphenyl tetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)hexafluoro Propionic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl) propionic dianhydride, etc.

As for the aliphatic tetracarboxylic dianhydride, the alicyclic type includes, for example, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5-(di Pendant oxytetrahydrofuranyl-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4-(2,5-dilateral oxytetrahydrofuran-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-cyclobutane tetracarboxylic dianhydride Carboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, etc.

Two or more types of these acid dianhydrides may be used in combination.

The acid dianhydride used to obtain the polyimide of the present invention is preferably a tetracarboxylic dianhydride having a rigid and linear structure, that is, a homogeneous dianhydride, from the viewpoint of the heat resistance of the polyimide molded article. Pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride.

When polymerizing the polyimide precursor of the present invention, in addition to the diamine represented by the general formula (1) above, the polymerization reactivity and the characteristics of the polyimide molded product will not be significantly impaired. In addition to the copolymer compound, an aromatic or aliphatic diamine compound may be used in combination as a copolymerization component.

Examples of aromatic diamines that can be used at this time include 2,2'-bis(trifluoromethyl)benzidine, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, and 2,5-diamine. Aminotoluene, 2,4-diaminoxylene, 2,4-diaminopyrene, 4,4'-diaminodiphenylmethane, 4,4'-methylenebis(2- Methylaniline), 4,4'-methylenebis(2-ethylaniline), 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-methylene Bis(2,6-diethylaniline), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether , 2,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide Methone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzoaniline, 4-aminophenyl-4'-aminobenzoate, benzidine, 3 ,3'-dihydroxybenzidine, 3,3'-dimethoxybenzidine, di-o-toluidine, di-m-toluidine, 1,4-bis(4-aminophenoxy)benzene, 1,3 -Bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4 -(3-Aminophenoxy)phenyl)sine, bis(4-(4-aminophenoxy)phenyl)sine, 2,2-bis(4-(4-aminophenoxy)) Phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, p-triphenyldi Amines etc.

In addition, the aliphatic diamine is a chain aliphatic or decyclic diamine. Examples of the decyclic diamine include 4,4'-methylenebis(cyclohexylamine), isophorone diamine, 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, Examples include 1,3-diamine adamantane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-aminocyclohexyl)hexafluoropropane, and chain aliphatic diamines. For example, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5- Pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine , diaminosiloxane, etc.

One or more types of these diamine compounds may be used in combination.

Among them, from the viewpoint of the solubility of polyimide in solvents and the heat resistance of polyimide molded products, diamine compounds having a rigid and linear structure, that is, 2,2'-bis( Trifluoromethyl)benzidine (hereinafter sometimes also referred to as TFMB) is suitable as a copolymerization component.

烷、二甲氧基乙烷、二乙氧基乙烷、二丁基醚等醚系溶劑。就其他泛用溶劑而言，亦可使用乙醯苯、1,3-二甲基-2-咪唑啶酮、環丁碸、二甲基亞碸、丙二醇甲基乙酸酯、乙基賽珞蘇(ethyl cellosolve)、丁基賽珞蘇、2-甲基賽珞蘇乙酸酯、乙基賽珞蘇乙酸酯、丁基賽珞蘇乙酸酯、丁醇、乙醇、二甲苯、 甲苯、氯苯、松節油、礦油精(mineral spirit)、石油腦系溶劑等。此等溶劑可混合2種以上而使用。 The preferred solvents used in the polymerization of the polyimide precursor are N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, Aprotic solvents such as dimethyl styrene can be used as long as they can dissolve the raw material monomers, the polyimide precursor to be produced, and the imidized polyimide. It is used according to the problem and is not particularly limited by the structure or type of the solvent. Specific examples include: amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and γ-butyrolactone , γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, butyl acetate, ethyl acetate, isobutyl acetate and other esters Solvents, 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, m-cresol , p-cresol, o-cresol, 3-chlorophenol, 4-chlorophenol and other phenolic solvents, cyclopentanone, cyclohexanone, acetone, methyl ethyl ketone, diisobutyl ketone, methyl isobutyl Ketone solvents such as ketones, tetrahydrofuran, 1,4-bis

Alkane, dimethoxyethane, diethoxyethane, dibutyl ether and other ether solvents. As for other commonly used solvents, acetobenzene, 1,3-dimethyl-2-imidazolidinone, cyclotenine, dimethylterosine, propylene glycol methyl acetate, and ethyl celluloid can also be used Ethyl cellosolve, butylcellosolve, 2-methylcellosolve, ethylcellosolve, butylcellosolve, butanol, ethanol, xylene, toluene , chlorobenzene, turpentine, mineral spirit (mineral spirit), naphtha solvents, etc. These solvents can be used by mixing 2 or more types.

The method for producing the polyimide of the present invention is not particularly limited, and known methods can be appropriately applied. Specifically, for example, it can be synthesized by the following method.

First, the diamine compound is dissolved in the polymerization solvent, and a powder of tetracarboxylic dianhydride that is substantially the same mole as the diamine compound is slowly added to the solution, and the mixture is stirred between 0 and 100° C. using a mechanical stirrer. Stir in the range (preferably 20 to 60°C) for 0.5 to 150 hours (preferably stir for 1 to 72 hours). At this time, the monomer concentration is usually in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight. By polymerizing in such a monomer concentration range, a polyimide precursor with a uniform and high degree of polymerization can be obtained. When the polymerization degree of the polyimide precursor increases excessively and the polymerization solution becomes difficult to stir, it can also be appropriately diluted with the same solvent. From the viewpoint of improving the mechanical strength of the polyimide molded article, the degree of polymerization of the polyimide precursor is preferably as high as possible. By polymerizing within the above monomer concentration range, the degree of polymerization of the polymer can be sufficiently high and the solubility of the monomer and polymer can be sufficiently ensured. If the polymerization is performed at a concentration lower than the above range, the degree of polymerization of the polyimide precursor may not be sufficiently high. Also, if the polymerization is performed at a concentration higher than the above monomer concentration range, the degree of polymerization of the polyimide precursor may not be sufficiently high. Insufficient dissolution of monomers or polymers to be produced. Furthermore, when an aliphatic diamine is used, the formation of salts frequently occurs in the initial stage of polymerization, hindering polymerization. However, in order to suppress the formation of salts and simultaneously increase the degree of polymerization as much as possible, it is preferable to control the monomer concentration during polymerization to the above-mentioned level. within the appropriate concentration range.

A method for imidization of the obtained polyimide precursor will be described.

For the imidization, a known imidization method can be applied. For example, the "thermal imidization method" in which a polyimide precursor film is thermally closed, or a polyimide precursor solution can be suitably used. exist The "solution thermal imidization method" that closes the cycle at high temperature, the "chemical imidization method" that uses a dehydrating agent, etc.

Specifically, in the "thermal imidization method", a polyimide precursor solution (such as polyamide acid) is cast on a substrate or the like at 50 to 200°C (preferably 60 to 150°C) After drying to form the polyimide precursor film, it is heated in an inert gas or under reduced pressure at 150°C to 400°C (preferably 200°C to 380°C) for 1 to 12 hours to cause thermal dehydration. The ring is closed and the imidization is completed, whereby the polyimide molded body of the present invention can be obtained.

In addition, in the "solution thermal imidization method", a solution of a polyimide precursor (for example, polyamide acid) to which an alkaline catalyst is added is heated at 100 to 250 in the presence of an azeotropic agent such as xylene. °C (preferably 150 to 220 °C) for 0.5 to 12 hours to remove the by-produced water from the system and complete the imidization, thereby obtaining the polyimide solution of the present invention.

In the "chemical imidization method", a polyimide precursor (for example, polyamide acid) is adjusted to a moderate solution viscosity that is easy to stir to obtain a polyimide precursor solution, and the polyimide precursor solution is The amine precursor solution is stirred with a mechanical stirrer, etc., while adding dropwise anhydride of organic acid and a dehydration ring-closing agent (chemical imidization agent) composed of amines as an alkaline catalyst, at 0 to 100°C. (Preferably at 10 to 50° C.) Stir for 1 to 72 hours to complete chemical imidization. At this time, the organic acid anhydride that can be used is not particularly limited, but examples thereof include acetic anhydride, propionic anhydride, and the like. Acetic anhydride is suitable for the reagent due to its rationality and ease of purification. In addition, pyridine, triethylamine, quinoline, etc. can be used as the alkaline catalyst. From the viewpoint of reagent processing and ease of separation, pyridine can be suitably used, but is not limited thereto. The amount of organic acid anhydride in the chemical imidization agent is in the range of 1 to 10 times the mole of the theoretical dehydration amount of the polyimide precursor (when it is set to polyamide acid), and more preferably 1 to 5 times. More. Furthermore, the amount of the alkaline catalyst is in the range of 0.1 to 2 times molar relative to the amount of organic acid anhydride, and more preferably in the range of 0.1 to 1 times molar.

In the "solution thermal imidization method" and "chemical imidization method", by-products (hereinafter referred to as impurities) such as catalysts, chemical imidization agents, and carboxylic acids are mixed into the reaction solution. Therefore, these can be removed and refined. A known method can be used for purification. For example, the simplest method is to use the following method: drop the imidized reaction solution into a large amount of poor solvent while stirring to precipitate the polyimide, then recover the polyimide powder and wash it repeatedly. Clean until impurities are removed, and then dry under reduced pressure to obtain polyimide powder. At this time, suitable solvents that can be used include alcohols such as water, methanol, ethanol, and isopropyl alcohol that precipitate polyimide, effectively remove impurities, and facilitate drying. These solvents can be mixed and used. If the concentration of the polyimide solution dropped into a poor solvent for precipitation is too high, the precipitated polyimide will become particles, and there is a possibility that impurities may remain in the coarse particles. It may take a long time to dissolve the obtained polyimide powder in the solvent. On the other hand, if the concentration of the polyimide solution is too thin, a large amount of poor solvent will be required, and the environmental load caused by waste solvent disposal will increase, and the manufacturing cost will become high, so it is undesirable. Therefore, the concentration of the polyimide solution when dropped into the poor solvent is 20% by weight or less, more preferably 10% by weight or less. The amount of poor solvent used at this time is preferably equal to or more than the polyimide solution, preferably 1.5 to 3 times the amount.

The obtained polyimide powder is recovered, and the residual solvent is removed by drying under reduced pressure or hot air drying. The drying temperature and time are not particularly limited as long as the polyimide does not deteriorate and the residual solvent does not decompose. It is preferably dried at a temperature ranging from 30 to 200°C for 48 hours or less.

Regarding the polyimide of the present invention, the intrinsic viscosity of the polyimide is preferably in the range of 0.1 to 10.0 dL/g, and more preferably in the range of 0.5 to 5.0 dL/g.

烷、二甲氧基乙烷、二乙氧基乙烷、二丁基醚等醚系溶劑。就其他泛用溶劑而言，亦可使用乙醯苯、1,3-二甲基-2-咪唑啶酮、環丁碸、二甲基亞碸、乙酸丁酯、乙酸乙酯、乙酸異丁酯、丙二醇甲基乙酸酯、乙基賽珞蘇、丁基賽珞蘇、2-甲基賽珞蘇乙酸酯、乙基賽珞蘇乙酸酯、丁基賽珞蘇乙酸酯、氯仿、丁醇、乙醇、二甲苯、甲苯、氯苯、松節油、礦油精、石油腦系溶劑等。此等溶劑可混合2種以上而使用。 The polyimide of the present invention is soluble in various solvents, and the solvent can be selected according to the intended use or processing conditions. For example, although not particularly limited, amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and γ- Butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone and other ester solvents, ethylene carbonate, propylene carbonate, etc. Carbonate solvents, glycol solvents such as diethylene glycol dimethyl ether, triethylene glycol, and triethylene glycol dimethyl ether, phenol, m-cresol, p-cresol, o-cresol, and 3-chlorophenol , 4-chlorophenol and other phenolic solvents, cyclopentanone, cyclohexanone, acetone, methyl ethyl ketone, diisobutyl ketone, methyl isobutyl ketone and other ketone solvents, tetrahydrofuran, 1,4-di

Alkane, dimethoxyethane, diethoxyethane, dibutyl ether and other ether solvents. As for other general solvents, acetobenzene, 1,3-dimethyl-2-imidazolidinone, cyclotetrane, dimethylterine, butyl acetate, ethyl acetate, isobutyl acetate can also be used Ester, propylene glycol methyl acetate, ethyl cellulose, butyl cellulose, 2-methyl cellulose acetate, ethyl cellulose acetate, butyl cellulose acetate, Chloroform, butanol, ethanol, xylene, toluene, chlorobenzene, turpentine, mineral spirits, naphtha solvents, etc. These solvents can be used by mixing 2 or more types.

The solid content concentration when the polyimide of the present invention is dissolved in a solvent to form a solution depends on the molecular weight of the polyimide, the production method, or the molded article to be produced, but 5% by weight or more is preferred. good. If the solid content concentration is too low, it may be difficult to form a film with a sufficient thickness. On the other hand, if the solid content concentration is high, the solution viscosity may be too high, making it difficult to form. The method for dissolving the polyimide of the present invention in a solvent is, for example, adding the polyimide powder of the present invention while stirring the solvent, in the air or in an inert gas at room temperature to the boiling point of the solvent. The temperature range below the point takes 1 hour to 48 hours to dissolve, and a polyimide solution can be formed.

In addition, in the polyimide of the present invention, additives such as release agents, fillers, silane coupling agents, cross-linking agents, end-capping agents, antioxidants, defoaming agents, and leveling agents can be added as needed.

The obtained polyimide solution can be formed by a known method. For example, to form a polyimide film, the polyimide solution can be cast on a support such as a glass substrate using a spatula, etc., and a hot air dryer, an infrared drying oven, a vacuum dryer, and a non-oxidizing The polyimide film is formed by drying in an oven (inert oven), usually in the range of 40 to 300°C, preferably in the range of 50 to 250°C.

The polyimide molded article of the present invention molded in the above manner has a glass transition temperature of 300°C or higher, so it is particularly suitable for use as a heat-resistant material, for example, when used in semiconductors or flexible wiring substrates. It can fully withstand the lead-free soldering installation temperature of 260°C, so it is suitable as an insulating material.

Example

Hereinafter, although the present invention will be specifically described with reference to Examples, it is not limited to these Examples. In addition, the physical property values in the following examples were measured by the following evaluation method.

<Related evaluation methods>

1. Infrared absorption spectrum

Fourier transform infrared spectrophotometer FT/IR4100 (manufactured by JASCO Corporation) was used, and the infrared absorption spectrum of the diamine compound was measured by the KBr method. In addition, the infrared absorption spectrum of polyimide was measured by preparing a thin film sample (approximately 5 μm thick).

2. ¹ H-NMR spectrum

Fourier transform nuclear magnetic resonance JNM-ECP400 (manufactured by JEOL) was used to measure the composition and chemically imidized polyimide powder in deuterated dimethylsulfoxide (DMSO) or deuterated chloroform (CDCl ₃ ). ¹ H-NMR spectrum.

3. Differential scanning calorimetry (melting point)

The melting point of the diamine compound was measured using a differential scanning calorimetry device DSC3100 (NETZSCH Corporation) in a nitrogen environment at a temperature rise rate of 2°C/min. The higher the melting point and the sharper the melting peak, the higher the purity.

4.Intrinsic viscosity

The reducing viscosity of a 0.5% by weight polyimide precursor solution or polyimide solution was measured at 30° C. using an Oswald viscometer. As the solvent, N-methyl-2-pyrrolidone (NMP) was used. This value is considered the intrinsic viscosity.

5. Solubility test of polyimide powder in solvents

For 0.1 g of polyimide powder, 9.9 g of the solvent described in Table 2 (solid content concentration: 1% by weight) was placed in a sample tube, stirred for 5 minutes using a test tube mixer, and the dissolved state was visually confirmed.

As solvents, N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), γ-butyrolactone (GBL) are used ), triethylene glycol dimethyl ether (Tri-GL).

Regarding the evaluation results, in Table 2, the case of dissolving at room temperature is expressed as ++, the case of dissolving by heating and maintaining uniformity even after being left to cool to room temperature is expressed as +, and the case of swelling/partial dissolution is expressed as + The situation of insoluble is expressed as ±, and the situation of insoluble is expressed as -.

6. Glass transition temperature: Tg

The glass transition temperature of the polyimide film was determined by using a thermal mechanical analysis device (TMA4000) of NETZSCH Company, and the dimensions of the polyimide film were set to width 5mm, length 15mm, and the load was set to film thickness (μm) ×0.5g, after temporarily raising the temperature to 150°C at 5°C/min (the first temperature rise), cooling to 20°C, and then raising the temperature at 5°C/min (the second temperature rise), the TMA curve from the second temperature rise It is determined by the tangent method (the intersection of the tangent line in the glass state and the tangent line after Tg).

7. Average linear thermal expansion coefficient: CTE

The linear thermal expansion coefficient of the polyimide film was determined by using TMA4000 manufactured by NETZSCH (sample size: width 5mm, length 15mm), setting the load to film thickness (μm) × 0.5g, and temporarily raising the temperature at 5°C/min. After (the first temperature rise) to 150°C, it was cooled to 20°C, and then the temperature was raised at 5°C/min (the second temperature rise). It was calculated from the TMA curve during the second temperature rise. The coefficient of linear thermal expansion is found as an average value between 100 and 200°C.

8. Thermal decomposition temperature (nitrogen), thermal decomposition temperature (air)

Use the thermogravimetric analysis device (TG-DTA2000) of NETZSCH Company to measure the initial weight loss of the polyimide film (20 μm thickness) by 5% in nitrogen or air during the heating process at a heating rate of 10°C/min. The temperature of the time. The higher the value, the higher the thermal stability.

9. Average refractive index: n _av

Using an Abbe refractometer (ABBE 1T) manufactured by ATAGO, the refractive index in the direction parallel to the polyimide film surface (n _in ) and perpendicular to the film thickness direction (n _out ) is calculated as Abbe refractometer (using sodium lamp, wavelength 589nm) was used for measurement.

From this refractive index, the average refractive index of the polyimide film (n _av = (2n _in +n _out )/3) was calculated.

10.Dielectric constant: ε _opt

Based on the average refractive index n _av of the polyimide film, the dielectric constant of the polyimide film (ε _opt =1.1×n _av ² ) is calculated.

11. Elastic modulus, maximum elongation at break

Using TENSILON UTM-2 (manufactured by A&D Co., Ltd.), a tensile test (extension speed: 8 mm/min) was performed on a test piece (3 mm × 30 mm) of the polyimide film, and the elasticity was determined from the initial slope of the stress-strain curve. Modulus (GPa), the maximum elongation at break (%) is calculated from the elongation at break of the film. The higher the maximum elongation at break, the higher the toughness of the film.

Example 1

Synthesis of diamine compound represented by general formula (1) of the present invention

Synthesis of Dinitro intermediates

In a 100mL three-neck flask, add 6.93g (30.7mmol) of 2-chloro-5-nitrotrifluorotoluene and HM44BP (2,2',3,3',5,5'-hexamethyl-biphenyl-4 , 4'-diol) 2.71g (10.0mmol), potassium carbonate 2.89g, N,N-dimethylformamide (DMF) 20mL, and stirred at 85°C for 2.5 hours under a nitrogen atmosphere. A precipitate is formed during the reaction. The reaction solution was poured into a large amount of water, and the precipitate was recovered. After the precipitate was washed with methanol, it was dried in a vacuum dryer at 100° C. for 12 hours (yield 5.60 g, yield 86%). The dried crude product was recrystallized with dimethylsulfoxide to obtain a white powder (overall yield 83%).

Identification of dinitrosome intermediates

The product was measured using a Fourier transform infrared spectrophotometer FT/IR4100 (manufactured by JASCO Corporation). The aromatic CH stretching vibration absorption band was confirmed at 3103 cm ^-1 and the aliphatic CH stretching vibration absorption band was confirmed at 2951 cm ^-1 . The nitro stretching vibration absorption band was confirmed at 1524 and 1357 cm ^-1 , and the ether COC stretching vibration absorption band was confirmed at 1252 and 1193 cm ^-1 .

The result of ¹ H-NMR measurement using Fourier transform nuclear magnetic resonance spectrophotometer JNM-ECP400 (manufactured by JEOL) can be attributed to (CDCl ₃ -d ₁ , δ, ppm): 8.63 (sd, J=2.6Hz, 2H) ,8.32-8.28(m,2H),6.98(s,1H),6.92(sd,J=3.3Hz,1H),6.70-6.64(m,2H),2.11-1.99(m,18H).

From the above analysis results, it was confirmed that the product was dinitroform.

In addition, the melting point was measured using a differential scanning calorimetry device DSC3100 (NETZSCH Co., Ltd.). As a result, a sharp melting peak was shown at 297°C, and it was inferred that the product was highly pure.

Synthesis of diamine compounds (reduction of dinitro intermediates)

Add 5.13g (7.91mmol) of dinitrobase, 0.514g of target carbon (Pd 10%) (approximately 55% water-moistened product) as a catalyst, and 120mL of DMF to a 200mL three-neck flask, and bubble hydrogen. Stir at 120°C for 5 hours. Thereafter, after leaving to cool to room temperature, the catalyst was filtered, the filtrate was poured into saturated brine, and the precipitate was recovered. The precipitate was washed with water, xylene, and methanol, and dried in a vacuum dryer at 120°C for 12 hours (yield 4.34g, yield 93%). 1.57 g of the obtained crude product was heated and dissolved in toluene (90 mL) and ethyl acetate (20 mL), and the recrystallized product was collected by filtration. The recovered crystals were washed with toluene and methanol and then dried under reduced pressure. The mixture was dried at 120°C for 12 hours to obtain white powder (overall yield 80%).

Identification of diamine compounds

The product was measured using a Fourier transform infrared spectrophotometer FT/IR4100 (manufactured by JASCO Corporation). The NH stretching vibration absorption band was confirmed at 3449 and 3346 cm ^-1 , and the aromatic CH stretching vibration absorption band was confirmed at 3011 cm ^-1 . The aliphatic CH stretching vibration absorption band was confirmed at 2919 cm ^-1 , and the ether COC stretching vibration absorption band was confirmed at 1348 and 1047 cm ^-1 .

The result of ¹ H-NMR measurement using Fourier transform nuclear magnetic resonance spectrophotometer JNM-ECP400 (manufactured by JEOL) can be attributed to (CDCl ₃ -d ₁ , δ, ppm): 7.00 (sd, J=4.0Hz, 2H) ,6.89(s,1H),6.84(sd,J=4.0Hz,1H),6.65-6.67(m,2H),6.28-6.34(m,2H),3.55(s,4H),1.93-2.17(m ,18H).

The elemental analysis values are estimated values of C: 65.30%, H: 5.14%, and N: 4.76%, and actual measured values of C: 65.06%, H: 5.16%, and N: 4.66%.

From these analysis results, it was confirmed that the product was a diamine compound.

Example 2

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound 25 mol%

0.4414g (0.75mmol) of the diamine compound synthesized in the above Example 1 and 0.7205g (2.25mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) were dissolved in dehydrated N-methyl-2 -pyrrolidinone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50mmol) and stirred at room temperature for 72 hours to obtain the pre-polyimide Polyamide (solid content concentration: 19.2% by weight). The intrinsic viscosity of the obtained polyamide acid was 1.29dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 2.95 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a homogeneous solution of 8.49% by weight. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 255° C. for 1 hour to remove residual strain.

Example 3

Polymerization of polyimide precursor; PMDA(50): s-BPDA(50)/diamine compound 50mol%

0.8829g (1.50mmol) of the diamine compound synthesized in the above Example 1 and 0.4803g (1.50mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) were dissolved in dehydrated NMP. Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 19.9% by weight) which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 0.91dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 1.57 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 15.8% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 250° C. for 1 hour to remove residual strain.

Example 4

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound 75 mol%

Dissolve 1.3243g (2.25mmol) of the diamine compound synthesized in the above Example 1 and 0.2402g (0.75mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in dehydrated NMP. Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 18.4% by weight) which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 0.46dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours.

The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 1.15 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 23.4% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried in a hot air dryer at 80°C. Dry for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 305° C. for 1 hour to remove residual strain.

Example 5

Preparation of polyimide solution and production of polyimide film

The polyimide powder of the above Example 4 was redissolved in γ-butyrolactone (GBL) at room temperature to prepare a 16.5% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was again heat-treated in vacuum at 325° C. for 1 hour to remove residual strain.

Example 6

Polymerization of polyimide precursor; PMDA(50): s-BPDA(50)/diamine compound 100mol%

Dissolve 1.7657g (3.00mmol) of the diamine compound synthesized in the above Example 1 in dehydrated NMP. Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 16.9% by weight) which is a polyimide precursor. The intrinsic viscosity of the obtained polyamide acid was 0.66dL/g.

chemical imidization reaction

After diluting the obtained polyamide solution with dehydrated NMP to a solid content concentration of 10.0% by weight, 3.0627g (30mmol) of acetic anhydride was added to the solution at room temperature while stirring the diluted solution. A mixed solution with 1.1865 g (15 mmol) of pyridine was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 2.30 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 15.2% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 315° C. for 1 hour to remove residual strain.

Example 7

Preparation of polyimide solution and production of polyimide film

The polyimide powder of Example 6 was dissolved in GBL at room temperature to prepare a uniform solution of 12.4% by weight. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 315° C. for 1 hour to remove residual strain.

Example 8

Polymerization of polyimide precursor; PMDA (100)/diamine compound 75 mol%

Dissolve 1.3243g (2.25mmol) of the diamine compound synthesized in the above Example 1 and 0.2402g (0.75mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in dehydrated NMP. 0.6544g (3.00mmol) of pyromellitic dianhydride (PMDA) powder was slowly added thereto, and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 15.8% by weight) which is a polyimide precursor. . The inherent viscosity of the obtained polyamide acid was 0.74dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The inherent viscosity of the obtained polyimide was 0.77dL/g.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 21.4% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 259° C. for 1 hour to remove residual strain.

Example 9

Polymerization of polyimide precursor; PMDA (100)/diamine compound 100 mol%

Dissolve 1.7657g (3.00mmol) of the diamine compound synthesized in the above Example 1 in dehydrated NMP. 0.6544g (3.00mmol) of pyromellitic dianhydride (PMDA) powder was slowly added thereto, and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 14.7% by weight) which is a polyimide precursor. . The intrinsic viscosity of the obtained polyamide acid was 1.11dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The inherent viscosity of the obtained polyimide was 1.10 dL/g.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 23.6% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 348° C. for 1 hour to remove residual strain.

Comparative example 1

Synthesis of dinitro intermediates (synthesis of methyl-free diamines)

Add 6.92g (30.7mmol) of 2-chloro-5-nitrotrifluorotoluene, 1.89g (10.1mmol) of 4,4'-biphenol, and 2.89g of potassium carbonate into a 100mL three-neck flask. g, N,N-dimethylformamide (DMF) 15mL, stir at 85°C for 4 hours under nitrogen atmosphere. The reaction solution was poured into a large amount of water, and the precipitate was recovered. The precipitate was washed with water and methanol, and then dried in a vacuum dryer at 80°C for 12 hours (yield 4.91g, yield 86%). The dried crude product was recrystallized with toluene to obtain white needle crystals (overall yield 72%).

Identification of dinitrosome intermediates

The product was measured using a Fourier transform infrared spectrophotometer FT/IR4100 (manufactured by JASCO Corporation). The aromatic CH stretching vibration absorption band was confirmed at 3109 cm ^-1 and the nitro stretching vibration absorption band was confirmed at 1530 and 1351 cm ^-1 . The ether COC stretching vibration absorption bands were confirmed at 1243 and 1049 cm ^-1 . The results of ¹ H-NMR measurement using Fourier transform nuclear magnetic resonance spectrophotometer JNM-ECP400 (manufactured by JEOL) can be attributed to (DMSO-d ₆ , δ, ppm): 8.55-8.48 (m, 4H), 7.86 (d , J=8.7Hz, 4H), 7.38 (d, J=8.7Hz, 4H), 7.22 (d, J=9.2Hz, 2H), it was confirmed that the product was a dinitroform. Furthermore, the melting point was measured using a differential scanning calorimeter DSC3100 (NETZSCH Co., Ltd.). As a result, a sharp melting peak was shown at 211° C., and it was inferred that the product was highly pure.

Reduction of Dinitro intermediates

Add 3.00g (5.32mmol) of dinitrobase, 0.303g of palladium/carbon (Pd 10%) (approximately 55% water-wet product) as a catalyst, and 90mL of DMF to a 200mL three-neck flask while bubbling hydrogen. While stirring at 100°C for 4 hours. Then, after leaving it to cool to room temperature, the catalyst was filtered, the filtrate was put into water, and the precipitate was recovered. The precipitate was washed with water and dried in a vacuum dryer at 100°C for 12 hours (yield 2.48g, yield 92%). 3.10 g of the obtained crude product was heated and dissolved in ethanol (15 mL), recrystallized, filtered and recovered, and dried in a vacuum dryer at 80° C. for 12 hours to obtain a gray powder (overall yield 65%).

Identification of diamine compounds

The product was measured using a Fourier transform infrared spectrophotometer FT/IR4100 (manufactured by JASCO Corporation). The NH stretching vibration absorption bands were confirmed at 3431 and 3358 cm ^-1 , and the aromatic CH stretching vibration absorption band was confirmed at 3040 cm ^-1 . The ether COC stretching vibration absorption bands were confirmed at 1228 and 10479 cm ^-1 .

The result of ¹ H-NMR measurement using Fourier transform nuclear magnetic resonance spectrophotometer JNM-ECP400 (manufactured by JEOL) can be attributed to (DMSO-d ₆ , δ, ppm): 7.56 (d, J = 8.7 Hz, 4H), 6.94-6.82(m,10H),5.46(s,4H), the elemental analysis values are estimated values C: 61.91%, H: 3.60%, N: 5.55%, actual measured values C: 61.80%, H: 3.85%, N :5.51%, confirming that the product was diamine. Furthermore, the melting point was measured using a differential scanning calorimeter DSC3100 (NETZSCH Co., Ltd.). As a result, a sharp melting peak was shown at 153° C., and it was estimated that the product was highly pure.

Comparative example 2

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound 0 mol%

0.9607g (3.00mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) was dissolved in dehydrated N-methyl-2-pyrrolidone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 17.4% by weight) which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 0.92dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and as a result, the fluidity disappeared and gelled.

Comparative example 3

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound (25 mol%)

0.3783g (0.75mmol) of the diamine compound synthesized in Comparative Example 1 above and 0.7205g (2.25mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) were dissolved in dehydrated N-methyl-2 -pyrrolidinone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 28.8% by weight) which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 1.38dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 1.286 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was dissolved in triethylene glycol dimethyl ether (Tri-GL) at room temperature to prepare a uniform solution of 18.1% by weight. The polyimide solution was cast on a glass substrate and dried in a hot air dryer at 80° C. for 1.5 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 260° C. for 1 hour to remove residual strain.

Comparative example 4

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound (50 mol%)

Dissolve 0.7566g (1.50mmol) of the diamine compound synthesized in Comparative Example 1 above and 0.4803g (1.50mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in dehydrated N-methyl-2 -pyrrolidinone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3’,4,4’-biphenyltetracarboxylic dianhydride (s-BPDA) powder. (1.50 mmol) was mixed at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 14.7% by weight), which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 1.09dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 1.90 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a uniform solution of 18.8% by weight. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 260° C. for 1 hour to remove residual strain.

Comparative example 5

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound (75 mol%)

Dissolve 1.1349g (2.25mmol) of the diamine compound synthesized in Comparative Example 1 above and 0.2402g (0.75mmol) of 2,2'-bis(trifluoromethyl)benzidine (TFMB) in dehydrated N-methyl-2 -pyrrolidinone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 19.0% by weight) which is a polyimide precursor. The intrinsic viscosity of the obtained polyamide acid was 1.29dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near δ11 ppm) that are unique to polyamide acid were not observed. It was speculated that the chemical imidization reaction had ended. The obtained polyimide had an intrinsic viscosity of 2.00 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a uniform solution of 18.8% by weight. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate together with the substrate was dried in a vacuum at 250°C for 1 hour and left to cool. After cooling to room temperature, the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 260° C. for 1 hour to remove residual strain.

Comparative example 6

Polymerization of polyimide precursor; PMDA (50): s-BPDA (50)/diamine compound (100 mol%)

1.5133g (3.00mmol) of the diamine compound synthesized in Comparative Example 1 was dissolved in dehydrated N-methyl-2-pyrrolidone (NMP). Slowly add 0.3272g (1.50mmol) of pyromellitic dianhydride (PMDA) powder and 0.4413g of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) powder ( 1.50 mmol) and stirred at room temperature for 72 hours to obtain polyamide acid (solid content concentration: 20.7% by weight) which is a polyimide precursor. The inherent viscosity of the obtained polyamide acid was 0.84dL/g.

chemical imidization reaction

The obtained polyamide solution was diluted with dehydrated NMP to a solid content concentration of 10.0% by weight, and then, while stirring the diluted solution, 3.0627g (30mmol) of acetic anhydride and 1.1865g (15mmol) of pyridine were mixed at room temperature. The mixed solution was slowly dripped, and after the dripping was completed, the mixture was further stirred for 24 hours. The obtained polyimide solution was slowly dropped into a large amount of ethanol to precipitate the polyimide. The obtained precipitate was thoroughly washed with ethanol and vacuum dried at 120°C for 12 hours. A proton NMR measurement was performed on this powder. As a result, COOH protons (near δ13 ppm) and NHCO protons (near 811 ppm) that are unique to polyamide acid were not observed. This suggests that the chemical imidization reaction has ended. The obtained polyimide had an intrinsic viscosity of 0.85 dL/g and was a high molecular weight body.

Preparation of polyimide solution and production of polyimide film

The above-mentioned polyimide powder was redissolved in NMP at room temperature to prepare a 19.2% by weight uniform solution. The polyimide solution was cast on a glass substrate and dried with a hot air dryer at 80° C. for 2 hours. Thereafter, the substrate was dried in a vacuum at 250° C. for 1 hour and allowed to cool to room temperature, and then the polyimide film was peeled off from the glass substrate. The polyimide film was heat-treated again in a vacuum at 245° C. for 1 hour to remove residual strain.

Regarding the polyimide membranes of Examples 2 to 9, the solution composition for membrane production and membrane physical property evaluation are summarized and shown in Table 1 below.

The solvent solubility of the polyimide powders of Examples 2 to 4, 6, 8, and 9 is summarized and shown in Table 2 below.

Regarding the polyimide membranes of Comparative Examples 2 to 6, the solution composition for membrane production and membrane physical property evaluation are summarized and shown in Table 3 below.

In addition, the glass transition temperature of Comparative Example 6 represents a value calculated from the loss peak at a frequency of 0.1 Hz, an amplitude of 0.1%, and a temperature rise rate of 5° C./min using a dynamic viscoelasticity measuring device (Q800) manufactured by TA Instruments.

The polyimide system that does not use the diamine compound synthesized in Example 1 is insoluble in the solvent as shown in Comparative Example 2, but the polyimide system that uses the diamine compound synthesized in Example 1 is insoluble in the solvent. The amide imine is soluble in the solvent as in Examples 2 to 9. Furthermore, the glass transition temperature of the polyimide film obtained from the solution is a high temperature of 330° C. or higher. On the other hand, the polyimide system using the diamine compound synthesized in Comparative Example 1 became soluble in the solvent as in Comparative Examples 2 to 6, but the glass transition temperature did not reach 300° C. and was in heat resistance. Sexual problems. From these Examples and Comparative Examples, it is believed that the diamine of the present invention is used which has 6 methyl groups at the 2, 2', 3, 3', 5, 5' positions of the central biphenyl group via the ether bond. The polyimide compound uses methyl groups to significantly twist the dihedral angle of the biphenyl group due to steric hindrance (non-coplanarity), hindering the cohesion between polymer chains and improving the solubility in solvents. In addition, the steric hindrance effect also inhibits the intramolecular rotation around the ether bond, so it will increase the heat resistance of the polyimide inserted into this structure, that is, it will increase the glass transition temperature.

Claims (6)

A diamine compound represented by the following general formula (1),

In the general formula, R ₁ and R ₂ are trifluoromethyl, R ₃ and R ₄ independently represent an alkyl group with 1 to 4 carbon atoms and an alkoxy group with 1 to 4 carbon atoms, a, b It is a combination of 0 and 1 or both are 1, c and d independently represent integers from 0 to 4, but the total of a and c and the total of b and d are each less than 4. A diamine compound represented by the following general formula (2),

In the general formula, R ₅ and R ₆ each independently represent a hydrogen atom or a trifluoromethyl group, and both or one of them is a trifluoromethyl group. A polyimide containing a structural unit represented by the following general formula (3),

In the general formula, R ₁ and R ₂ are trifluoromethyl, R ₃ and R ₄ independently represent an alkyl group with 1 to 4 carbon atoms and an alkoxy group with 1 to 4 carbon atoms, a, b is a combination of 0 and 1 or both are 1, c and d independently represent integers from 0 to 4, and X represents a 4-valent aromatic and/or aliphatic group, but the sum of a and c The total of b and d is 4 or less respectively. A polyimide containing a structural unit represented by the following general formula (4),

In the general formula, R ₅ and R ₆ independently represent a hydrogen atom or a trifluoromethyl group, and both or one of them is a trifluoromethyl group. X represents a tetravalent aromatic and/or aliphatic group. . A polyimide solution includes the polyimide described in item 3 or 4 of the patent application and a solvent. A polyimide formed body is obtained from the polyimide solution described in item 5 of the patent application scope.

Images