JPH07268097A - Polyimide of good thermal oxidation stability and its production - Google Patents

Abstract

PURPOSE:To obtain a polyimide excellent in thermal oxidation stability, dimensional stability, flame retardancy and electrical insulation properties. CONSTITUTION:This polyimide is the one having a C1 content of 10ppm or below and comprising repeating units represented by the formula (wherein R1 is a 2-27C bivalent group selected from the group consisting of an aliphatic group, a cycloaliphatic group, a monocyclic aliphatic group, a fused polycyclic aromatic group and a nonfused polycyclic aromatic group composed of aromatic groups bonded with each other directly or through bridging members; and R2 is a 2-27C tetravalent group selected from the group consisting of an aliphatic group, a cycloaliphatic group, a monocyclic aliphatic group, a fused polycyclic aromatic group and a nonfused polycyclic aromatic group composed of aromatic groups bonded with other directly or through bridging members).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin having good thermal oxidation stability and a method for producing the same. More specifically, the present invention relates to a polyimide resin having a good thermal oxidation stability, which has a Cl content of 10 ppm or less, and a method for producing the same.

[0002]

2. Description of the Related Art Polyimide has not only high heat resistance but also excellent mechanical strength, dimensional stability, flame retardancy and electrical insulation. Therefore, it has been used in the fields of electric / electronic equipment, aerospace equipment, transportation equipment, etc., and is expected to be widely used in various fields where heat resistance is required. Polyimides having excellent properties have been developed. Generally, polyimide resins are known to have excellent heat resistance and chemical resistance, but at the same time, many polyimide resins are inferior in moldability due to this property. In order to overcome these drawbacks, it is possible to impart solvent solubility (FW Harris et al., Ap.
plied poly. Symposium, 6, p.
425-428 (1975)), imparting thermoplasticity (USP 4,847,349 etc.), etc.
Many studies have been made. However, the present situation is that, among heat resistance, a method for improving thermo-oxidative stability is hardly studied.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to disclose a polyimide resin having good thermal oxidation stability and a method for producing the same.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that the Cl content is greatly involved in the thermal oxidation stability of polyimide. Completed the invention. That is, the present invention provides C
General formula (I) with a 1-minute content of 10 ppm or less [Chemical formula 4]

[0005]

[Chemical 4] (In the formula, R ₁ has 2 to 27 carbon atoms, and an aliphatic group, a cycloaliphatic group, a monocyclic aliphatic group, a condensed polycyclic aromatic group and / or an aromatic group is a direct or crosslinking member. Represents a divalent group which is a non-condensed polycyclic aromatic group interconnected by
₂ has ₂ to 27 carbon atoms, an aliphatic group, a cycloaliphatic group,
It represents a monovalent aliphatic group, a condensed polycyclic aromatic group, and / or a tetravalent group which is a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a crosslinking member. ) A polyimide resin having a good thermal oxidation stability having a repeating structural unit represented by and / or a polyimide resin having a good thermal oxidation stability in which the molecular end of the polyimide is sealed with a monoamine compound and / or a dicarboxylic acid anhydride, and,
General formula (II) [Chemical formula 5]

[0006]

Embedded image A diamine compound represented by H ₂ N—R ₁ · NH ₂ (II) (wherein R ₁ is the same as above) and a general formula (III)

[0007]

[Chemical 6] (In the formula, R ₂ is the same as above.) The total content of Cl in the tetracarboxylic dianhydride is 10 ppm or less, and is represented by the general formula (II). A polyimide having good thermal oxidation stability obtained by reacting a diamine compound and a tetracarboxylic acid dianhydride represented by the general formula (III) in the presence or absence of a monoamine compound and / or a dicarboxylic acid anhydride. Is a method of manufacturing.

The polyimide represented by the general formula (I) in the present invention means a polymer containing an imide bond. Also, with Cl content, including chloride ions,
It means all chlorine compounds including chloride, and all Cl atoms that can be recognized by silver nitrate titration after hydrolysis, including Cl ₂ and crystals containing it. Further, the diamine compound represented by the general formula (II) used in the method of the present invention, in the general formula (I), R ₁ is an aliphatic group;
R ₁ is a cycloaliphatic group such as ethylenediamine and 1,4-diaminobutane; R ₁ is a monocyclic aromatic group such as 1,4-diaminocyclohexane; m-phenylenediamine, o-phenylenediamine , P-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, diaminotoluene and the like, R ₁ is a condensed polycyclic aromatic group; 2,6-diaminonaphthalene and the like, R ₁ is an aromatic group. A non-fused cyclic aromatic group directly linked; 4,4 '
- diaminobiphenyl, 4,3'-diamino biphenyl, and the like, R ₁ is a non-fused cyclic aromatic groups linked by a bridge member to an aromatic group; 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 sulfoxide, 3,4 '
-Diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3 '
-Diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,
3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) Phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-
Aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane,
1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-
Aminophenoxy) phenyl] butane, 1,2-bis [4- (4-aminophenoxy) phenyl] butane,
1,3-bis [4- (4-aminophenoxy) phenyl] butane, 1,4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) Phenyl] butane, 2,3-bis [4-
(4-Aminophenoxy) phenyl] butane, 2- [4
-(4-Aminophenoxy) phenyl] -2- [4-
(4-Aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-aminophenoxy)-
3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane,
2,2-bis [4- (4-aminophenoxy) -3,5
-Dimethylphenyl] propane, 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 (4-aminophenoxy) biphenyl, bis [4- (4-Aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4-
(4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether,
Bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4-
(4-Aminophenoxy) benzoyl] benzene, 1,
4-bis [4- (3-aminophenoxy) benzoyl]
Benzene, 4,4'-bis (3-aminophenoxy) benzoyl] benzene, 4,4'-bis (3-aminophenoxy) -3,3'-dimethylbiphenyl, 4,4'-
Bis (3-aminophenoxy) -3,5-dimethylbiphenyl, 4,4'-bis (3-aminophenoxy)-
3,3 ', 5,5'-tetramethylbiphenyl, 4,
4'-bis (3-aminophenoxy) -3,3'-dichlorobiphenyl, 4,4'-bis (3-aminophenoxy) -3,3 ', 5,5'-tetrachlorobiphenyl,
4,4'-bis (3-aminophenoxy) -3,5-dibromobiphenyl, 4,4'-bis (3-aminophenoxy) -3,3 ', 5,5'-tetrabromobiphenyl, bis [4 -(3-aminophenoxy) -3-methoxyphenyl] sulfide, [4- (3-aminophenoxy) phenyl] [4- (3-aminophenoxy) -3,
5-dimethoxyphenyl] sulfide, bis [4- (3
-Aminophenoxy) -3,5-dimethoxyphenyl]
Sulfide, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-amino) Phenoxy) phenyl] propane,
2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4 -(3-Aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl]
Examples thereof include sulfide and bis [4- (3-aminophenoxy) phenyl] sulfone. Among these diamine compounds, a diamine compound which is often used as a particularly useful raw material for polyimide is a compound represented by the general formula (II) in which R ₁ is represented by the formula (IV)

[0009]

[Chemical 7] Represents )) Is a diamine compound which is a group represented by. The above compounds are exemplified as specific compounds.

The general formula (II) used in the method of the present invention is also
The tetracarboxylic dianhydride represented by I) is represented by the general formula (III), for example, R ₂ is an aliphatic group;
R ₂ is a cycloaliphatic group such as butanetetracarboxylic dianhydride; cyclopentanetetracarboxylic dianhydride,
R ₂ is a monocyclic aromatic group such as cyclohexanetetracarboxylic dianhydride; 1,2,3,4-benzenetetracarboxylic dianhydride, pyromellitic dianhydride, R ₂
Is a condensed polycyclic aromatic group; 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6 -Naphthalene tetracarboxylic dianhydride, 1,2,3,4-
Benzenetetracarboxylic dianhydride, 3,4,9,10
-Perylene tetracarboxylic dianhydride, 2,3,6,7
-Anthracene tetracarboxylic dianhydride, 1,2,
7,8-phenanthrenetetracarboxylic dianhydride, etc.,
R ₂ is a non-fused cyclic aromatic group in which aromatic groups are directly linked; 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetra R ₂ is a non-condensed cyclic aromatic group in which aromatic groups are linked by a bridging member, such as carboxylic acid dianhydride; 3,3 ′, 4,4′-
Benzophenone tetracarboxylic dianhydride, 2,2 ',
3,3′-benzophenone tetracarboxylic acid dianhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) Propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (2,3-
Dicarboxyphenyl) ether dianhydride, bis (3,
4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride,
Bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-Dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,2-bis (2,3
-Dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride,
1,3-bis (2,3-dicarboxyphenoxy) benzene dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (2,3-
Dicarboxyphenoxy) benzene dianhydride, 1,4-
Bis (3,4-dicarboxyphenoxy) benzene dianhydride, 2,2'-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, bis [4-
(3,4-dicarboxyphenoxy)] biphenyl dianhydride and the like. Among these tetracarboxylic acid dianhydrides, compounds which are frequently used as raw materials for useful polyimides include compounds represented by the general formula (III) in which R ₂ is represented by the formula (V)

[0011]

[Chemical 8] Represents )) Is a group of compounds.

Further, in order to produce a polyimide excellent in thermal oxidation stability in the present invention, the above diamine compound having a total Cl content of 10 ppm or less and the tetracarboxylic dianhydride component are mixed and heated and melted. Although it is possible to produce by doing so, it is particularly preferable to carry out the reaction in an organic solvent. Examples of the organic solvent used in the present invention 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, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethylurea, hexamethylphosphoramide, phenol, o-cresol, m-
Cresol, p-cresol, m-cresylic acid, p-
Examples include chlorophenol and anisole. Also,
These organic solvents may be used alone or in combination of two or more.

Also in the present invention, there is no problem even if an organic base catalyst, which is usually used when synthesizing a polyimide, coexists. As the organic base catalyst, triethylamine,
Tributylamine, tripentylamine, N, N-dimethylaniline, N, N-diethylaniline, pyridine,
α-picoline, β-picoline, γ-picoline, 2,4-
Examples thereof include lutidine, 2,6-lutidine, quinoline, isoquinoline and the like, with preference given to pyridine and γ-picoline.

Further, in the case of producing a polyimide suitable for use as a molding material or the like, there are known methods for end-capping a polymer terminal by using a monoamine, a dicarboxylic acid anhydride or the like. Can be applied to the present invention. Examples of the monoamine compound and / or dicarboxylic acid anhydride used as the terminal blocking agent include aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,6-xylidine, and 3 , 4-xylidine, 3,5-xylidine,
o-chloroaniline, m-chloroaniline, p-chloroaniline, o-bromoaniline, m-bromoaniline,
p-bromoaniline, o-nitroaniline, p-nitroaniline, m-nitroaniline, o-aminophenol, m-aminophenol, p-aminophenol, o
-Anisidine, m-anisidine, p-anisidine, o-
Phenetidine, p-phenetidine, m-phenetidine,
o-aminobenzaldehyde, m-aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzonitrile, m-aminobenzonitrile, p-aminobenzonitrile, 2-aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, 2- Aminophenyl phenyl ether, 3-aminophenyl phenyl ether,
4-aminophenyl phenyl ether, 2-aminobenzophenone, 3-aminobenzophenone, 4-aminobenzophenone, 2-aminophenylphenyl sulfide, 3-aminophenylphenyl sulfide, 4-aminophenylphenyl sulfide, 2-aminophenylphenyl sulfone, 3-aminophenylphenyl sulfone, 4-aminophenylphenyl sulfone, α-naphthylamine, β-naphthylamine, 1-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1.
-Naphthol, 5-amino-1-naphthol, 5-amino-2-naphthol, 7-amino-2-naphthol, 8
-Amino-1-naphthol, 8-amino-2-naphthol, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, phthalic anhydride, 2,3
-Benzophenone dicarboxylic acid anhydride, 3,4-benzophenone dicarboxylic acid anhydride, 2,3-dicarboxyphenylphenyl ether anhydride, 3,4-dicarboxyphenylphenyl ether acid anhydride, 2,3-biphenyldicarboxylic acid anhydride Substance, 3,4-biphenyldicarboxylic acid anhydride, 2,3-dicarboxyphenylphenyl sulfone anhydride, 3,4-dicarboxyphenylphenyl sulfone anhydride, 2,3-dicarboxyphenylphenyl sulfide anhydride, 3, 4-dicarboxyphenyl phenyl sulfide anhydride, 1,2-naphthalenedicarboxylic acid anhydride, 2,3-naphthalenedicarboxylic acid anhydride,
1,8-naphthalenedicarboxylic acid anhydride, 1,2-anthracene dicarboxylic acid anhydride, 2,3-anthracene dicarboxylic acid anhydride, 1,9-anthracene dicarboxylic acid anhydride and the like can be mentioned. Among these monoamine compounds and / or dicarboxylic acid anhydrides, aniline and / or phthalic anhydride are most preferable from the viewpoint of performance and practical use of the obtained polyimide.

The polyimide of the formula (I) according to the present invention can be produced by any known method. That is, 1) polyamic acid is synthesized in an organic solvent, and the solvent is removed at a low temperature using a method such as vacuum distillation, or the obtained polyamic acid solution is discharged into a poor solvent to isolate the polyamic acid. After that, this is heated to imidize to obtain a polyimide. 2) After preparing a polyamic acid solution in the same manner as 1),
A method in which a dehydrating agent typified by acetic anhydride is added, and a catalyst is added if necessary to chemically imidize the polyimide, and then the polyimide is isolated by a known method, and washed and dried if necessary. 3) A method in which a polyamic acid solution is obtained in the same manner as in 1), and then the solvent is removed by reduced pressure or heat treatment, and at the same time, thermal imidization is performed. 4) A method in which raw materials are charged into an organic solvent and then heated to simultaneously perform the synthesis of polyamic acid and the imidization reaction, and to make a catalyst, an azeotropic agent, and a dehydrating agent coexist if necessary. And so on.

In the method of the present invention, the method of adding and reacting diamines, tetracarboxylic dianhydrides, and dicarboxylic acid anhydrides or aromatic monoamines in an organic solvent includes (i) tetracarboxylic acid A method in which a dianhydride and a diamine are reacted and then a dicarboxylic acid anhydride or an aromatic monoamine is added to continue the reaction. (B) Dicarboxylic acid anhydride is added to the diamine and then reacted, and then tetracarboxylic acid dianhydride is added to continue the reaction, or aromatic monoamine is added to the tetracarboxylic acid dianhydride and reacted, and then diamine The method of continuing the reaction by adding. (C) A method in which a tetracarboxylic acid dianhydride, a diamine and a dicarboxylic acid anhydride or an aromatic monoamine are simultaneously added to cause a reaction. There is no problem even if either method is used. The reaction temperature is usually 300 ° C. or lower, and the reaction pressure is not particularly limited and can be sufficiently carried out at normal pressure. The reaction time varies depending on the type of diamine, the type of tetracarboxylic dianhydride, the type of solvent, the presence or absence of a catalyst, and the reaction temperature, but 4 to 24 hours is usually sufficient. In the present invention, it is disclosed that a polyimide, which originally has excellent properties, causes a decrease in thermo-oxidative stability due to the contained Cl component and causes a decrease in molding processability. Polyimide resin will have higher heat resistance in the future,
Although excellent mechanical properties and molding processability are required, the present invention provides a polyimide that can meet such requirements and a method for producing the same. This use is highly expected.

[0017]

The present invention will be described in detail below with reference to Synthesis Examples, Examples and Comparative Examples. The Cl content and various physical properties in the examples were measured by the following methods. Cl content: N / 100 by silver nitrate titration. The titration was carried out using a Shibata Scientific Instruments E-536 type potentiograph. Logarithmic viscosity: 0.50 g of polyimide powder was dissolved by heating in 100 ml of a mixed solvent of p-chlorophenol and phenol (90:10 weight ratio), and then cooled to 35 ° C. for measurement. Glass transition temperature (Tg): measured by DSC (Shimadzu DT-40 series, DSC-41M). 5% weight loss temperature: DTA-TG (Shimadzu DT in air
-40 series, 40M). Melt viscosity: Koka type flow tester (Shimadzu C
FT-500, orifice diameter 0.1 cm, length 1c
m, pressure 100 kg).

Example 1 A stirrer, a reflux condenser, a water separator and a nitrogen inlet tube were installed.
In the container provided, the Cl content measured using silver nitrate titration
6 ppm of 4,4'-bis (3-aminophenoxy) bi
Phenyl 36.8 g (0.10 mol), Cl content 2 pp
20.8 g (0.0953) of pyromellitic dianhydride of m
Mol), Cl content 3ppm phthalic anhydride 1.39g
(9.4x10^-3Mol), 1.38 g of γ-picoline
(1.5x10 ^-2Mol) and m-cresol 230 g
Charged at 145 ° C with stirring under a nitrogen atmosphere.
It was heated up to. During this period, about 3.4 g of water was distilled off.
It has been certified. Further, the reaction is performed at 140 to 150 ° C. for 4 hours.
It was Then cool to room temperature and add 800 g of methyl ethyl.
After discharging to the ketone, it was filtered off. This polyimide powder is
Wash further with chill ethyl ketone and smell under nitrogen atmosphere
And pre-dry at 50 ° C for 24 hours, then at 200 ° C at 6:00
54.6 g (yield 98.5%) of polyimide after drying
Got the powder. The logarithmic viscosity of this polyimide powder is 0.49 dl
/ G, Tg is 249 ℃, 5% weight loss temperature in air is
It was 545 ° C. Using the obtained polyimide powder, 4
Relationship between residence time in cylinder and melt viscosity at 20 ℃
I checked. The results are summarized in (Table 1).

COMPARATIVE EXAMPLE 1 4,4'-bis (3-aminophenoxy) biphenyl having a Cl content of 6 ppm in Example 1 was mixed with a Cl content of 5
54.6 g (yield 98.5%) of polyimide powder was obtained in exactly the same manner except that the amount of 4,4′-bis (3-aminophenoxy) biphenyl was changed to 0 ppm. This polyimide has an inherent viscosity of 0.49 dl / g and a Tg of 249 ° C., 5
The% weight loss temperature was 543 ° C. Using the obtained polyimide powder, the relationship between the residence time in the cylinder and the melt viscosity was examined in the same manner as in Example 1. The results are collectively shown in (Table 1) together with the results of Example 1. From the results in (Table 1), it can be seen that the polyimide of Example 1 has much more excellent melt viscosity stability.

Example 2 A container equipped with a stirrer, a reflux condenser, a water separator and a nitrogen inlet tube had 3,3'-diaminobenzophenone 21.2 with a Cl content of 3 ppm measured by silver nitrate titration.
g (0.10 mol), Cl content 2 ppm 3,3 ',
4,4'-benzophenone tetracarboxylic dianhydride 3
0.6 g (0.0951 mol), 1.39 g (9.4 × 10 ⁻³ mol) of phthalic anhydride having a Cl content of 3 ppm, 1.38 g (1.5 × 10 ⁻² mol) of γ-picoline and m- 230 g of cresol was charged and the temperature was raised to 145 ° C. with stirring under a nitrogen atmosphere. During this time, about 3.4
Distillation of g of water was confirmed. Furthermore, the reaction was carried out at 140 to 150 ° C. for 4 hours. Then, cool to room temperature, 800
After discharging into g of methyl ethyl ketone, it was filtered off. The polyimide powder was further washed with methyl ethyl ketone, pre-dried under a nitrogen atmosphere at 50 ° C. for 24 hours, and then dried at 200 ° C. for 6 hours to obtain 48.6 g (yield 98.
0% of polyimide powder was obtained. The polyimide powder had an inherent viscosity of 0.40 dl / g, a Tg of 240 ° C., and a 5% weight loss temperature in air of 540 ° C. Using the obtained polyimide powder, the relationship between the residence time in the cylinder at 380 ° C. and the melt viscosity was examined. The results are summarized in (Table 2).

Comparative Example 2 21.2 g (0.10 mol) of 3,3'-diaminobenzophenone having a Cl content of 3 ppm in Example 2 was added to Cl.
Amount of 60 ppm 3,3'-diaminobenzophenone 2
Polyimide powder 48.6 g (yield 98.0%) in the same manner as in Example 2 except that the amount was changed to 1.2 g (0.10 mol).
Got The logarithmic viscosity of this polyimide powder is 0.40 dl /
The g and Tg were 240 ° C and the 5% weight loss temperature was 540 ° C. Using the obtained polyimide powder, the relationship between the residence time in the cylinder and the melt viscosity was examined in the same manner as in Example 2. The results are collectively shown in (Table 2) together with the results of Example 2. From the results in (Table 2), it can be seen that the polyimide of Example 2 has much more excellent melt viscosity stability.

Example 3 Commercially available 4,4'-diaminodiphenyl ether 20 was placed in a vessel equipped with stirring, a reflux condenser and a nitrogen introducing tube.
g (0.1 mol), pyromellitic dianhydride 21.8 g
(0.1 mol), N, N-dimethylacetamide 232
g was charged, and stirring was continued under a nitrogen stream at room temperature for 24 hours. The polyamic acid thus obtained had an inherent viscosity of 1.98 dl /
It was g. The polyamic acid varnish thus obtained was cast on a glass plate to a finished thickness of 50 μm,
A polyimide film was obtained by heating in a nitrogen atmosphere at 100 ° C., 200 ° C. and 300 ° C. for 1 hour each. The tensile strength of this polyimide film is 21.0 kg /
mm ² , tensile elongation of 68% (measurement method is AST
It is based on MD-882). The resulting polyimide film is left in the air at 350 ° C., and after 24 hours, 5
The tensile strength and the tensile elongation after 0 hours were measured. The results are shown in (Table 3).

Comparative Example 3 To the polyamic acid varnish obtained in Example 3, 0.01 g of NaCl was added, and after the polyamic acid varnish obtained after stirring for about 5 hours, a polyimide film was prepared in the same manner as in Synthesis Example 3. Obtained. The measurement results of the tensile strength and the tensile elongation of this polyimide film, and the tensile strength and the tensile elongation after standing at 350 ° C. for 24 hours and 50 hours in the air as in Example 3 are the same as those of Example 3. The results are also shown in (Table 3). From the results of (Table 3), Example 3
It can be seen that the polyimide film of No. 1 retains excellent mechanical properties after heat history at 350 ° C.

[0024]

[Table 1] (Table 1) ────────────────────────────────── Melt viscosity at 420 ° C in the cylinder ( Poise) Residence time (min) Polyimide of Comparative Example 1 of Example 1 Polyimide Polyimide ────────────────────────────────── ─ 5 7200 7600 30 7300 10200 60 7400 14100 ───────────────────────────────────

[0025]

[Table 2] (Table 2) ────────────────────────────────── Melt viscosity at 380 ° C in the cylinder ( Poise) Dwell time (min) Polyimide of Comparative Example 2 of Example 2 Polyimide Polyimide ────────────────────────────────── ─ 5 8300 8500 30 8300 11000 60 8400 16200 ───────────────────────────────────

[0026]

[Table 3]

[0027]

Industrial Applicability According to the present invention, a polyimide having excellent thermal oxidative stability is provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Yamaguchi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (3)

[Claims] 1. A compound represented by the general formula (I) [Chemical formula 1] having a Cl content of 10 ppm or less. (In the formula, R ₁ has 2 to 27 carbon atoms, and an aliphatic group, a cycloaliphatic group, a monocyclic aliphatic group and / or a condensed polycyclic aromatic group, or an aromatic group is a direct or crosslinking member. Represents a divalent group which is a non-condensed polycyclic aromatic group interconnected by
₂ has ₂ to 27 carbon atoms, an aliphatic group, a cycloaliphatic group,
It represents a tetravalent group which is a monocyclic aliphatic group, a condensed polycyclic aromatic group and / or a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a bridging member. ) A polyimide having good thermal oxidation stability and having a repeating structural unit represented by 2. The molecular end of the polymer is capped with a monoamine compound and / or a dicarboxylic acid anhydride.
A polyimide having good thermal oxidation stability as described. 3. A general formula (II) for producing a polyimide having a repeating structural unit represented by the general formula (I).
[Chemical Formula 2] [Chemical Formula 2] H ₂ N—R ₁ · NH ₂ (II) (wherein R ₁ is the same as above) and a general formula (III) [Chemical Formula 3] 3] (In the formula, R ₂ is the same as above.) The total content of Cl in the tetracarboxylic dianhydride is 10 ppm or less, and is represented by the general formula (II). A diamine compound and a tetracarboxylic acid dianhydride represented by the general formula (III) are obtained by reacting in the presence or absence of a monoamine compound and / or a dicarboxylic acid. 2. A method for producing a polyimide having good thermal oxidation stability according to 2.