JP3015591B2 - Polyimide having good moldability and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyimide for melt molding. More specifically, the present invention relates to a polyimide excellent in moldability and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a polyimide obtained by reacting a tetracarboxylic dianhydride with a diamine has excellent mechanical strength and dimensional stability in addition to its high heat resistance, flame retardancy,
It is used in the fields of electrical and electronic equipment, aerospace equipment, transportation equipment, etc., because it also has electrical insulation properties.
It is expected that it will be widely used in fields where co-heat resistance is required.

Hitherto, various polyimides exhibiting excellent characteristics have been developed. However, even if it has excellent heat resistance, it does not have a clear glass transition temperature, so when it is used as a molding material, it must be processed using a method such as sinter molding, and the workability is excellent. However, it is soluble in halogenated hydrocarbon solvents and has problems in terms of solvent resistance and has advantages and disadvantages in performance. For example, polyimide obtained from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride is represented by the formula (5)

Embedded image Is a polyimide having a basic skeleton represented by
It is known as a highly heat-resistant polyimide developed by DuPont (manufactured by DuPont; trade name: Kapon, Vespel). However, although this polyimide does not have a clear glass transition temperature and has excellent heat resistance, it is difficult to process when used as a molding material, and has the drawback that it must be processed using a technique such as sinter molding. are doing.

Some studies have been made on the use of a diamine having an isopropylidene group as a diamine component of polyimide. For example, the formula (6) obtained from 2,2-bis (4-aminophenyl) propane and pyromellitic dianhydride

Embedded image (GM Bower et al., J. Polymer Sci ,: pt-A, 1, 3135-
3150 (1963); CESrog et al., J. Polymer Sci ,: pt-A, 3, 137
3-1390 (1965)) are known. However, since this polyimide does not show thermoplasticity and does not melt and flow under heating, it has a drawback that molding processing is difficult.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyimide having excellent moldability in addition to the excellent heat resistance inherent to polyimide.

[0006]

Means for Solving the Problems The inventors of the present invention diligently aim to improve the moldability of polyimide without impairing the excellent properties inherent to polyimide, such as heat resistance, mechanical properties, and chemical resistance. As a result of the study, the present invention has been reached.

That is, the present invention relates to (1) a general formula (1)

Embedded image [Wherein, R is (a) a monocyclic aromatic group represented by the following formula;

Embedded image And (b) a non-fused polycyclic aromatic group in which aromatic groups represented by the following formulas are connected to each other directly or by a bridging member:

Embedded image (In the formula, X ₁ represents a tetravalent group selected from the group consisting of a direct bond, —O— and —CO—). General formula (2)

Embedded image (Where X is

Embedded image Represents a divalent group selected from the group consisting of: a) a dicarboxylic anhydride-capped polyimide, especially 0.5 g / p-chlorophenol / phenol (9/1 by weight) in a mixed solvent. After melting by heating at dl concentration, 35
The value of the logarithmic viscosity measured at 0.1 ° C. is 0.1 to 2.0 dl.
/ G is a polyimide having good moldability, and

(2) Equation (3)

Embedded image And an aromatic diamine mainly composed of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene represented by the formula:
General formula of molar ratio (4)

Embedded image [Wherein, R is (a) a monocyclic aromatic group represented by the following formula;

Embedded image And (b) a non-fused polycyclic aromatic group in which aromatic groups represented by the following formulas are connected to each other directly or by a bridging member:

Embedded image (Wherein X ₁ represents a tetravalent group selected from the group consisting of a direct bond, —O— and —CO—). Per mole of the general formula (2)

Embedded image (Where X is

Embedded image A polyamic acid obtained by reacting in the presence of an aromatic dicarboxylic anhydride represented by the formula (1), wherein the resulting polyamic acid is thermally or chemically imidized: It is a manufacturing method of.

In the polyimide of the present invention, the aromatic dicarboxylic anhydride of the general formula (2) used for terminal blocking is particularly preferably phthalic anhydride. The polyimide of the present invention has the general formula (1)

Embedded image (Wherein R is the same as described above), and a polyimide having a repeating structural unit represented by the general formula (2)

Embedded image (Wherein, X is the same as described above), which is a polyimide sealed with an aromatic dicarboxylic anhydride.

[0010] These polyimides can be produced by the following production method. The starting diamine compound used in the method of the present invention has the formula (3)

Embedded image 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene represented by Although the polyimide of the present invention is a polyimide using the above-mentioned diamine compound as a raw material, other diamines may be mixed and used within a range that does not impair the good physical properties of the polyimide.

Examples of the diamines which can be used in combination are o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 2-chloro-1,2-diamine.
Phenylenediamine, 4-chloro-1,2-phenylenediamine, 2,3-diaminotoluene, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 3,4-diaminotoluene, 2 -Methoxy-1,4-phenylenediamine, 4-methoxy-1,
2-phenylenediamine, 4-methoxy-1,3-phenylenediamine, benzidine, 3,3′-dichlorobenzine, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,
4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulphoxide, 3,
4'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfoxide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,
3'-diaminodiphenylbenzophenone, 3,4'-
Diaminodiphenylbenzophenone, 4,4′-diaminodiphenylbenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane,
4,4'-diaminodiphenylmethane, bis [4- (3
-Aminophenoxy) phenyl] methane, bis [4-
(4-aminophenoxy) phenyl] methane, 1,1-
Bis [4- (3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4
-(3-aminophenoxy) phenyl] propane, 2,
2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy)
Phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (3
-Aminophenoxy) phenyl] -1,1,1,3,
3,3-hexafluoropropane, 2,2-bis [4-
(4-aminophenoxy) phenyl] -1,1,1,
3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4
-Aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4 ' -Bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] Sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4-
(3-aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl]
Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1, 3-bis [4-
(3-aminophenoxy) benzoyl] benzene, 4,
4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [3- (3-
Aminophenoxy) benzoyl] diphenyl ether,
4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone , Screws [4- @ 4- (4
-Aminophenoxy) phenoxydiphenyl] ketone,
Bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4 -(4-aminophenoxy)-
α, α-dimethylbenzyl] benzene, bis [4- {4
-(4-aminophenoxy) phenoxydiphenyl] sulfone and the like.

The tetracarboxylic dianhydride represented by the general formula (4) used in the method of the present invention includes: (a) a monocyclic aromatic group represented by the following formula:

Embedded image Or (b) a non-condensed polycyclic aromatic group in which aromatic groups represented by the following formulas are connected to each other directly or through a bridging member:

Embedded image (Wherein X ₁ represents a direct bond, —O— or —CO—)
Is used.

Specifically, pyromellitic dianhydride,
3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride Is mentioned.

The polyimide of the present invention is represented by the general formula (4) and an aromatic diamine mainly comprising 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene of the formula (3). The tetracarboxylic dianhydride is represented by the general formula (2)

Embedded image (Where X is

Embedded image The polyamic acid obtained by the reaction in the presence of a dicarboxylic anhydride represented by the formula (II) is thermally or chemically imidized.

The dicarboxylic anhydride used in these methods includes phthalic anhydride, 3,4-benzophenone dicarboxylic anhydride, and 2,3-naphthalenedicarboxylic anhydride. These dicarboxylic anhydrides may be substituted with a group which does not react with the amine or dicarboxylic anhydride.

The amount of the dicarboxylic anhydride used is 1,3-bis (4-amino-α, α represented by the formula (3):
-Dimethylbenzyl) 0.001 per mole of benzene
１．０1.0 molar ratio. If the amount is less than 0.001 mol, the viscosity is increased during high-temperature molding, which causes a reduction in molding processability. On the other hand, if it exceeds 1.0 mol, the mechanical properties deteriorate. The preferred amount is 0.01 to 0.5 mol. Therefore, when producing the polyimide in the present invention, tetracarboxylic dianhydride, aromatic diamine,
The molar ratio of dicarboxylic anhydride and tetracarboxylic dianhydride per mole of aromatic diamine is 0.8-1.
0 mol and the amount of dicarboxylic anhydride is 0.001 to 1.0 mol.

In the production of polyimide, it is common practice to adjust the ratio of aromatic diamine to tetracarboxylic dianhydride in order to adjust the molecular weight of the resulting polyimide. In the method of the present invention, in order to obtain a polyimide having good melt fluidity, the molar ratio of tetracarboxylic dianhydride to aromatic diamine is set to 0.8 to 1.0. As a method for producing the polyimide of the present invention, any method capable of producing polyimide, including known methods, can be applied. Among them, it is particularly preferable to carry out the reaction in an organic solvent.

Examples of the organic solvent used in such a method include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide,
N, N-dimethylmethoxyacetamide, N-methyl-
2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2
-Bis (2-methoxyethoxy) ethane, bis @ 2-
(2-methoxyethoxy) ethyl ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane,
Examples include pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethyl urea, hexamethylene phosphoramide, phenol, m-cresol, p-cresol, o-cresol, anisole, p-chlorophenol and the like. These organic solvents may be used alone or in combination of two or more.

In the method of the present invention, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene,
As a method of adding and reacting tetracarboxylic dianhydride and aromatic dicarboxylic anhydride, (a) 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene and tetracarboxylic dianhydride are used. A method of continuing the reaction by adding an aromatic dicarboxylic anhydride after the reaction, (b)
A method in which an aromatic dicarboxylic anhydride is added to 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene and reacted, tetracarboxylic dianhydride is added, and the reaction is further continued ( C) 1,3-bis (4-amino-
α, α-Dimethylbenzyl) benzene, tetracarboxylic dianhydride, and aromatic dicarboxylic anhydride may be simultaneously added and reacted, and any addition method may be used.

The reaction temperature is usually 250 ° C. or lower, preferably 50 ° C. or lower. The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure. The reaction time varies depending on the type of tetracarboxylic dianhydride, the type of solvent and the reaction temperature, and usually 4 to 24 hours is sufficient. Further, the obtained polyamic acid is heated to 100 to 400 ° C. for imidization, or chemically imidized using an imidizing agent such as acetic anhydride to obtain a polyimide having a repeating unit corresponding to the polyamic acid. Is obtained. When 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, tetracarboxylic dianhydride and aromatic dicarboxylic anhydride are added, they are suspended or dissolved in an organic solvent. After heating, the imidation is carried out simultaneously with the generation of the polyamic acid which is a precursor of the polyimide, whereby the desired polyimide can be obtained. Further, when subjecting the polyimide of the present invention to melt molding, other thermoplastic resins within a range that does not impair the purpose of the present invention, for example, polyethylene,
Polypropylene, polycarbonate, polyarylate,
An appropriate amount of polyamide, polysulfone, polyether sulfone, polyether ketone, polyphenyl sulfide, polyamide imide, polyether imide, modified polyphenylene oxide or the like can be blended according to the purpose.

Further, the following fillers and the like used in ordinary resin compositions may be used to such an extent that the effects of the present invention are not impaired. That is, graphite, carborundum, silica stone powder, molybdenum disulfide, abrasion resistance improver such as fluorine resin, glass fiber, carbon fiber, boron fiber, silicon carbide fiber, carbon whisker, asbestos, metal fiber, ceramic fiber and the like Reinforcing material, flame retardant improver such as antimony trioxide, magnesium carbonate, calcium carbonate, etc., electric property improver such as clay, mica, etc.
Tracking resistance improver such as asbestos, silica, graphite, acid resistance improver such as barium sulfate, silica, calcium metasilicate, thermal conductivity improver such as iron powder, zinc powder, aluminum powder, copper powder, other glass beads,
Glass spheres, talc, diatomaceous earth, alumina, shirasubarun, hydrated alumina, metal oxides, coloring agents and the like.

[0022]

The present invention will be described below with reference to examples and comparative examples. In the examples, various physical properties were measured by the following methods. Logarithmic viscosity: Measured at 35 ° C. after heating and dissolving 0.50 g of polyimide powder in 100 ml of a mixed solvent of p-chlorophenol / phenol (weight ratio 9/1). Glass transition temperature (Tg): Measured by DSC (Shimadzu DT-40 series, DSC-41M). 5% weight loss temperature: DTA-TG (Shimadzu DT-
40 series, DSC-40M). Melt viscosity: Measured with a Shimadzu Koka type flow tester CFT500A at a load of 100 kg using an orifice having an inner diameter of 1 mm and a length of 10 mm.

Example 1 34.45 g (0.100 mol) of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene was placed in a reactor equipped with a stirrer, a reflux condenser and a nitrogen inlet tube. N-
22.44 g of methylpyrrolidone was charged and 21.16 g of pyromellitic dianhydride was added at room temperature under a nitrogen atmosphere.
(0.097 mol) while paying attention to the rise in the solution temperature, followed by stirring at room temperature for about 20 hours. Thereafter, 2.67 g (0.018 mol) of phthalic anhydride was added, and stirring was further continued for 3 hours. 278.05 g of N-methylpyrrolidone was added to the polyamic acid solution, and while stirring, 1.30 g of isoquinoline and 40.84 g of acetic anhydride were added under a nitrogen atmosphere.
After dropping g, the temperature was raised to 70 ° C. and the mixture was stirred at 70 ° C. for 4 hours.
After cooling, the mixture was discharged into 2 l of methyl ethyl ketone, and the yellow powder was separated by filtration. The yellow powder was further washed with methyl ethyl ketone, preliminarily dried at 50 ° C. for 15 hours under a nitrogen stream, and further dried at 250 ° C. for 4 hours under a nitrogen stream to obtain 51.84 g.
(98% yield) was obtained. The logarithmic viscosity of the polyimide powder thus obtained was 0.42 dl / g. The crystal melting temperature (Tm) of this polyimide powder is 404
° C. The 5% weight loss temperature in air is 50%.
5 ° C. FIG. 1 shows an infrared absorption spectrum of this polyimide powder. In this spectrogram, 1780 cm ^-1 imide characteristic absorption bands of absorption around 1720 cm ^-1 were clearly observed. The elemental analysis values of the obtained polyimide powder were as follows. Elemental analysis value CHN Calculated value (%) 77.55 4.98 5.32 Analysis value (%) 77.51 4.97 5.34 The melt viscosity of the polyimide powder obtained in this example is increased by the formula shown below. Using a flow tester, load 100kg and diameter 1
The measurement was performed using an orifice having a length of 10 mm and a length of 10 mm. 4
The melt viscosity at 10 ° C. was 2,600 poise. Further, the molding stability of the polyimide obtained in this example was determined by measuring the melt viscosity in a flow tester cylinder while changing the residence time. The temperature was 410 ° C. and the load was 100 kg. The results are shown in FIG. Even if the residence time in the cylinder becomes longer, the melt viscosity hardly changes, indicating that the thermal stability is good.

Comparative Example 1 A polyimide powder was obtained in the same manner as in Example 1 except that phthalic anhydride was not used. Crystal melting temperature (Tm) of polyimide powder
Was 401 ° C. and the logarithmic viscosity was 0.43 dl / g. When the melt viscosity was measured by changing the residence time in the flow tester cylinder in the same manner as in Example 1, the melt viscosity increased as the residence time increased, as shown in FIG.
The heat stability was inferior to that of the polyimide obtained in Example 1.

Example 2 34.45 g of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene was placed in the same reactor as in Example 1.
(0.100 mol) and N-methylpyrrolidone 222.4
4g and 3,3 ', 4,4' at room temperature under nitrogen atmosphere
-Benzophenonetetracarboxylic dianhydride 30.61
g (0.095 mol) was added while paying attention to the rise in the solution temperature, and the mixture was stirred at room temperature for about 20 hours. Thereafter, 4.80 g (0.032 mol) of phthalic anhydride was added, and the mixture was further stirred for 3 hours. To this polyamic acid solution, 324.66 g of N-methylpyrrolidone was added, and while stirring, 1.30 g of isoquinoline and 40.84 g of acetic anhydride were added dropwise under a nitrogen atmosphere, and then 61.68 g (yield 9) as in Example 1.
8.0%) of a polyimide powder. The logarithmic viscosity of the polyimide powder thus obtained was 0.54 dl / g. The glass transition temperature (Tg) of this polyimide powder was 211 ° C., and the crystal melting temperature (Tm) was 306 ° C. The 5% weight loss temperature in air was 522 ° C. FIG. 3 shows an infrared absorption spectrum of this polyimide powder.
In this spectrum, 178, which is a characteristic absorption band of imide, is used.
Absorption in the vicinity of 0cm ^-1 and 1720cm ^-1 was observed significantly. The elemental analysis values of the obtained polyimide powder were as follows. Elemental analysis value Calculated value of CHN (%) 78.08 4.79 4.44 Analysis value (%) 78.02 4.82 4.46 100kg load and 1mm diameter 10
It was measured using an orifice of mm. The melt viscosity at 370 ° C. was 8,700 poise. Further, the obtained strand was pale yellow, transparent, flexible, and tough. In addition, the molding stability of the polyimide obtained in this example was determined by measuring the melt viscosity in a flow tester cylinder while changing the residence time. Temperature is 370 ° C, load 100kg
I went in. The results are shown in FIG. Even when the residence time in the cylinder became longer, the melt viscosity hardly changed, and the thermal stability was good.

Comparative Example 2 A polyimide powder was obtained in the same manner as in Example 2 except that phthalic anhydride was not used. Glass transition temperature of polyimide powder (T
g) was 212 ° C. and the logarithmic viscosity was 0.53 dl / g. When the residence time in the flow tester cylinder was changed and the melt viscosity was measured in the same manner as in Example 2, the melt viscosity increased as the residence time became longer as shown in FIG. The heat stability was inferior to the obtained polyimide.

Example 3 A polyimide powder was prepared in the same manner as in Example 2 except that 6.34 g (0.032 mol) of 2,3-naphthalenedicarboxylic anhydride was used instead of the phthalic anhydride used in Example 2. Obtained.

Examples 4, 5 Instead of pyromellitic dianhydride used in Example 1, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride 28.25 g (0.096 mol) and Screw (3, 4
-Dicarboxyphenyl) ether dianhydride 29.78
g (0.096 mol) was used to obtain a polyimide powder in the same manner as in Example 2.

Example 6 Instead of the phthalic anhydride used in Example 5, 3,05-benzophenone dicarboxylic anhydride (6.05 g, 0.024 g) was used.
Mol) to obtain a polyimide powder in the same manner as in Example 1.

Example 7 A polyimide powder was prepared in the same manner as in Example 1 except that 4.76 g (0.024 mol) of 2,3-naphthalenedicarboxylic anhydride was used instead of the phthalic anhydride used in Example 6. Obtained. Table 1 summarizes the amounts of the diamine compound and the tetracarboxylic anhydride used in the reactions in Examples 3 to 8 and the basic physical properties of the obtained polyimide.

[0031]

[Table 1]

[0032]

The polyimide of the present invention is a polyimide excellent in moldability without deteriorating the heat resistance inherent to the polyimide, and the polyimide whose polymer terminal is sealed with the above dicarboxylic anhydride is particularly excellent. It is characterized by having processability and chemical resistance, is excellent in melt flow stability as compared with conventionally known polyimides, and has greatly improved molding processability, and the present invention provides industrially extremely useful polyimides. It is newly provided.

[Brief description of the drawings]

FIG. 1 is a diagram of an infrared absorption spectrum of a polyimide powder obtained in Example 1.

FIG. 2 shows the molding stability of the polyimide powder of Example 1 compared to the polyimide powder obtained in Comparative Example 1 at a temperature of 410 ° C. under a load of 100 kg while changing the residence time in a cylinder of a flow tester while changing the melt viscosity. It is a figure showing a result.

FIG. 3 is an infrared absorption spectrum of the polyimide powder obtained in Example 2.

FIG. 4 is a view showing the results of measuring the melt viscosity of each polyimide powder obtained in Example 2 and Comparative Example 2 at a temperature of 370 ° C. and a load of 100 kg while changing the residence time in a cylinder of a flow tester.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-96219 (JP, A) JP-A-3-43419 (JP, A) JP-A 64-22963 (JP, A) JP-A 64-64 121 (JP, A) JP-A-59-170122 (JP, A) JP-A-3-160025 (JP, A) JP-A-4-108880 (JP, A) JP-B-38-5997 (JP, B1)

Claims (2)

(57) [Claims] 1. A compound of the general formula (1) Wherein R is (a) a monocyclic aromatic group represented by the following formula : And (b) an aromatic group represented by the following formula is directly or
Non-fused interconnected polycyclic aromatic radical embedded image by ( Wherein X ₁ represents a direct bond, —O— or —CO—
Represents a tetravalent group selected from the group consisting of :), and the molecular terminal of the polymer is represented by the general formula (2): (In the formula, X [of 5] A divalent anhydride selected from the group consisting of: 2. Formula (3) And an aromatic diamine mainly composed of 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene represented by the formula:
Formula molar ratio (4) embedded image [Wherein R is (a) a monocyclic aromatic group represented by the following formula : And (b) an aromatic group represented by the following formula is directly or
Mutual unfused linked to a polycyclic aromatic group embedded image by ( Wherein X ₁ represents a direct bond, —O— or —CO—
The tetracarboxylic acid dianhydride represented by representing] a tetravalent group selected from the group consisting of be), the diamine compound per mol of general formula 0.001 to 1.0 molar ratio
(2) [of 10] (In the formula, X [of 11] Wherein the resulting polyamic acid is thermally or chemically imidized in the presence of an aromatic dicarboxylic anhydride represented by the formula: Item 10. A method for producing a polyimide according to Item 1.