JPH06271670A - Colorless transparent polyimide of good thermal stability and its production - Google Patents

Abstract

PURPOSE:To obtain the subject polyimide of high light transmittance, excellent in mechanical strength, dimensional stability and electrical insulation, useful for films etc., by reaction between each specific diamine, tetracarboxylic dianhydride and aromatic dicarboxylic anhydride at specified proportion. CONSTITUTION:The objective polyimide made up of recurring structural unit of formula IV as the basic skeleton can be obtained by reaction between (A) a diamine compound of formula I (X is SO2, O, CO, CH2 or S) such as 3,3'- diaminodiphenylsulfone, (B) 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3- hexafluoropropane dianhydride of formula II and (C) an aromatic dicarboxylic anhydride of formula III (Y is 6-15C divalent monocyclic aromatic group, condensed polycyclic aromatic group, etc.) such as phthalic anhydride in a molar ratio A/B/C of 1:(0.9-1.0):(0.01-1.0).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colorless transparent polyimide having good thermal stability and a method for producing the same. For more details,
The present invention relates to a polyimide film having a significantly high light transmittance, an almost colorless and transparent polyimide film, and good thermal stability.

[0002]

2. Description of the Related Art Conventionally, polyimide resins obtained by the reaction of tetracarboxylic dianhydride and diamine have not only high heat resistance but also mechanical strength, dimensional stability, flame retardancy, electrical insulation and the like. And is used as a material or as a heat-resistant adhesive in the fields of electric and electronic equipment, aerospace equipment, transportation equipment, and the like. For example, as one of the product forms of the polyimide resin, the polyimide film is expected to be widely used in the field where heat resistance is required in the future due to its excellent physical properties. However, many of the polyimides that have been developed so far have excellent properties, but generally have low light transmittance, often dark yellow or dark brown, and particularly low transmittance in the visible region, making them even more visible in outer space. It has the drawback of darkening the color. On the other hand, polyester films and aliphatic polyimide films have been developed that are colorless and transparent or have a hue close to that, but they are inferior in long-term heat resistance and weather resistance. In the field of space development in recent years, a film that absorbs less cosmic rays is required as a coverlay for solar cells. A method for producing a colorless transparent polyimide is disclosed in JP-A-63-1.
70420 discloses a homopolymer represented by the following general formula (6) or a copolymer represented by the following general formulas (6) and (7) (chemical formula 7).

[0003]

[Chemical 7] When the polyimide disclosed herein is compared with other aromatic polyimides, the transparency is remarkably excellent, but the heat resistance originally possessed by the polyimide is not sufficiently satisfied.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a polyimide having not only the excellent thermal stability inherent in polyimide, but also the property of remarkably high light transmittance.

[0005]

[Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive studies for achieving the above object. That is, in the present invention, the polymer molecule end is represented by the following general formula (1)

[0006]

[Chemical 8] General formula (5) Z-NH ₂ (5) [wherein Y and Z each have 6 to 15 carbon atoms, and a monocyclic aromatic group, a condensed polycyclic aromatic group, and an aromatic group are It represents a group selected from the group consisting of non-condensed polycyclic aromatic groups linked to each other directly or by a cross-linking member, Y is a divalent group and Z is a monovalent group. ] The following general formula (2) (Chemical Formula 9) capped with an aromatic dicarboxylic acid anhydride or an aromatic monoamine represented by

[0007]

[Chemical 9] [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. ] It is a colorless transparent polyimide having good thermal stability having a repeating structural unit represented by the basic skeleton,
In addition, the following general formula (3)

[0008]

[Chemical 10] [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. ] And the diamine compound represented by the formula (4) (Chemical formula 11) in a molar ratio of 0.9 to 1.0 per mole of the diamine compound.

[0009]

[Chemical 11] A tetracarboxylic acid dianhydride represented by 2,2
-Bis (3,4-dicarboxyphenyl) -1,1,
1,3,3,3-hexafluoropropane dianhydride,
0.001-1.0 per mol of this diamine compound
Molar ratio of general formula (1)

[0010]

[Chemical 12] [In the formula, Y is a monocyclic aromatic group having 6 to 15 carbon atoms, a condensed polycyclic aromatic group, or a non-condensed polycyclic aromatic group in which aromatic groups are directly or cross-linked to each other. A divalent group selected from the group consisting of] is reacted in the presence of an aromatic dicarboxylic acid anhydride represented by the above general formula (2) It is a method for producing a colorless transparent polyimide having a basic skeleton and excellent thermal stability. Furthermore, the tetracarboxylic dianhydride represented by the above general formula (4), that is, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane A dianhydride and a diamine compound represented by the above general formula (3) in a molar ratio of 0.9 to 1.0 per 1 mol of the tetracarboxylic dianhydride are added per 1 mol of the tetracarboxylic dianhydride. , 0.001 to 1.0 molar ratio of the aromatic monoamine represented by the general formula (5) is reacted in the presence of the general formula (2).
Is a method for producing a colorless transparent polyimide having a repeating structural unit represented by the following as a basic skeleton and having good thermal stability.

In other words, the present invention provides a method for producing a polyimide in which a diamine compound is reacted with a tetracarboxylic dianhydride to thermally or chemically imidize the obtained polyamic acid. In the diamine compound represented by the formula (3), the tetracarboxylic acid dianhydride is the tetracarboxylic acid dianhydride represented by the formula (4), and these are added in an amount of 0.001 to 1 mol per mol of the diamine compound. The reaction is carried out in the presence of the aromatic dicarboxylic acid anhydride of the general formula (1) in a molar ratio of 1.0, or 0.0 per 1 mol of the tetracarboxylic acid dianhydride.
A colorless and transparent polyimide having good thermal stability, which comprises reacting in the presence of an aromatic monoamine of the general formula (5) in a molar ratio of 01 to 1.0, and a method for producing the same.

The polyimide of the present invention is manufactured as follows. Examples of the diamine compound represented by the general formula (3) used for producing the polyimide of the present invention include:
3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4 '
-Diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone,
4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,
3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide and the like can be mentioned, and these can be used alone or in admixture of two or more.

Incidentally, there is no problem in substituting a part of the above-mentioned diamine compound with another diamine compound as long as the good physical properties of the polyimide of the method of the present invention are not impaired. Examples of the diamine compound that can be used as a partial substitute include m-phenylenediamine and o-
Phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis (3-aminophenyl) sulfoxide, bis (4-aminophenyl) sulfoxide, (3-aminophenyl)
(4-aminophenyl) sulfoxide, 2,4'-diaminodiphenyl ether, 2,3'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether,
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- (3-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, 2,2-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 (4-aminophenoxy) biphenyl, bis [4
-(4-Aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl ] Sulfoxide, 4,4'-bis (3-aminophenoxy) diphenyl sulfone, 4,4'-bis (4-aminophenoxy) diphenyl sulfone, bis [4- (3
-Aminophenoxy) phenyl] ether, bis [4-
(4-Aminophenoxy) phenyl] ether, 1,4
-Bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy)
Benzoyl] benzene, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-
Aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane,
1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2- [4- (3-aminophenoxy) phenyl]- 2- [4- (3-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (3-aminophenoxy) -3-methylphenyl] propane, 2- [4- (3-amino) Phenoxy) phenyl] -2- [4- (3-aminophenoxy) -3,
5-dimethylphenyl] propane, 2,2-bis [4-
(3-Aminophenoxy) -3,5-dimethylphenyl] propane, 1,1-bis [4- (3-aminophenoxy) phenyl] butane, 1,2-bis [4- (3-aminophenoxy) phenyl] Butane, 1,3-bis [4
-(3-Aminophenoxy) phenyl] butane, 1,4
-Bis [4- (3-aminophenoxy) phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, 2,3-bis [4- (3-aminophenoxy) phenyl] butane , 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) -3-methylbiphenyl, 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) -3,5'-dichlorobiphenyl,
4,4'-bis (3-aminophenoxy) -3,3 ',
5,5'-tetrachlorobiphenyl, 4,4'-bis (3-aminophenoxy) -3,3'-dibromobiphenyl, 4,4'-bis (3-aminophenoxy) -3,
5'-dibromobiphenyl, 4,4'-bis (3-aminophenoxy) -3,3 ', 5,5'-tetrabromobiphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4 -(3-aminophenoxy) phenyl] sulfide, 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 and the like.

The tetracarboxylic dianhydride used in the present invention is 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3 represented by the above formula (4).
Although it is 3,3-hexafluoropropane dianhydride, other tetracarboxylic acid dianhydride may be partially substituted within a range not impairing the object of the present invention. The tetracarboxylic acid dianhydride that can be partially substituted and used, pyromellitic dianhydride, ethylene tetracarboxylic acid dianhydride, butanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, 3, 3 ', 4,
4'-benzophenone tetracarboxylic dianhydride, 2,
2 ', 3,3'-benzophenone tetracarboxylic 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, 2,2-
Bis (2,3-dicarboxyphenyl) -1,1,1,
3,3,3-hexafluoropropane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
Bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-Dicarboxyphenyl) ethane dianhydride, 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,3
4-dicarboxyphenyl) ethane dianhydride, 1,2-
Bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 4,4′- (P-Phenylenedioxy) diphthalic acid dianhydride, 4,4 ′-(m-phenylenedioxy)
Diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride , 1,2,7,8-phenanthrenetetracarboxylic dianhydride, and the like,
There is no problem even if two or more of these are mixed.

As the aromatic dicarboxylic acid anhydride represented by the general formula (1) used in the method of the present invention,
For example, phthalic anhydride, 2,3-benzophenone dicarboxylic acid anhydride, 3,4-benzophenone dicarboxylic acid anhydride, 2,3-dicarboxyphenylphenyl ether anhydride, 3,4-dicarboxyphenylphenyl ether anhydride, 2,3-biphenyldicarboxylic acid anhydride,
3,4-biphenyldicarboxylic acid anhydride, 2,3-dicarboxyphenylphenyl sulfone anhydride, 3,4-dicarboxyphenylphenyl sulfone anhydride, 2,3-
Dicarboxyphenyl phenyl 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 etc. are mentioned, These are used individually or in mixture of 2 or more types.

The aromatic monoamine represented by the general formula (5) used in the method of the present invention is, for example,
Aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,6-xylidine,
3,4-xylidine, 3,5-xylidine, o-chloroaniline, m-chloroaniline, p-chloroaniline,
o-bromoaniline, m-bromoaniline, p-bromoaniline, o-nitroaniline, m-nitroaniline,
p-nitroaniline, o-aminophenol, m-aminophenol, p-aminophenol, o-anisidine, m-anisidine, p-anisidine, o-phenidine, m-phenidine, p-phenidine, o-aminobenzaldehyde, m -Aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzonitrile, m-
Aminobenzonitrile, p-aminobenzonitrile, 2
-Aminobiphenyl, 3-aminobiphenyl, 4-aminobiphenyl, 2-aminophenylphenyl 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- Examples thereof include aminoanthracene, and these may be used alone or in combination of two or more.

The molar ratio of the diamine compound, the tetracarboxylic dianhydride, the aromatic dicarboxylic acid anhydride and the aromatic monoamine used in the present invention can be represented as follows. When using an aromatic dicarboxylic acid anhydride,
The tetracarboxylic dianhydride is 0.9 to 1.0 mole ratio and the aromatic dicarboxylic anhydride is 0.001 to 1.0 mole ratio per 1 mole of the diamine compound. However, if it is less than 0.9 mol ratio, a sufficient degree of polymerization cannot be obtained. Aromatic dicarboxylic acid anhydride,
If it is less than 0.001 mol ratio, the colorless transparency desired by the present invention cannot be obtained. On the other hand, if it exceeds 1.0 mol ratio, the mechanical properties are deteriorated. The preferred amount used is 0.01-
It is 0.5 molar ratio.

When an aromatic monoamine is used, the diamine compound is used in a ratio of 0.9 to 1.0 and the aromatic monoamine is used in a ratio of 0.001 to 1.0 per 1 mol of tetracarboxylic dianhydride. At this time, if the diamine compound is less than 0.9 mol ratio, a sufficient degree of polymerization cannot be obtained. If the aromatic monoamine is less than 0.001 mol ratio, the colorless transparency which is the object of the present invention cannot be obtained. On the other hand, if it exceeds 1.0 mol ratio, the mechanical properties are deteriorated. The preferred amount used is 0.01 to 0.5 molar ratio.

The polyimide of the present invention is usually produced in an organic solvent. Examples of the organic solvent used in this reaction 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, m-cresol, p- Cresol, p
-Chlorophenol, anisole and the like. These organic solvents may be used alone or in combination of two or more.

The polyimide of the present invention is manufactured as follows using the above-mentioned monomer and solvent. Diamine compound as starting material, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, aromatic dicarboxylic acid anhydride, aromatic As a method of adding and reacting a monoamine, (a)
After reacting a diamine compound with 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, an aromatic dicarboxylic acid anhydride is added. Then, the reaction is continued by adding an aromatic dicarboxylic acid anhydride to the (b) diamine compound and reacting, and then 2,2-bis (3,4-dicarboxyphenyl)-
A method in which 1,1,1,3,3,3-hexafluoropropane dianhydride is added and the reaction is continued, (2) bis (3,4-dicarboxyphenyl) -1 is added to the diamine compound. , 1,1,3,3,3-hexafluoropropane dianhydride and aromatic dicarboxylic acid anhydride are added at the same time,
Method of reacting, (d) 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride and diamine compound are reacted, and then the aromatic A method of adding a group monoamine to continue the reaction,
(E) 2,2-bis (3,4-dicarboxyphenyl)
A method in which an aromatic monoamine is added to -1,1,1,3,3,3-hexafluoropropane dianhydride and reacted, and then a diamine compound is added, and the reaction is further continued, (f)
2,2-bis (3,4-dicarboxyphenyl) -1,
Any method such as a method of simultaneously adding and reacting a diamine compound and an aromatic monoamine to 1,1,3,3,3-hexafluoropropane dianhydride may be used.

The reaction temperature is 0 to 250 ° C. Usually, it is performed at a temperature of 60 ° C or lower. The reaction pressure is not particularly limited and can be carried out at normal pressure. The reaction time varies depending on the type of diamine compound, aromatic dicarboxylic acid anhydride, aromatic monoamine, solvent used, and reaction temperature, but usually 4 to 24 hours is sufficient. By such a method, a polyamic acid having a repeating unit represented by the following general formula (6) (Formula 13) as a basic skeleton is produced.

[0022]

[Chemical 13] [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. The polyamic acid is dehydrated by heating at 100 to 400 ° C. or chemically imidized with a commonly used imidizing agent such as triethylamine or acetic anhydride to give a polyamic acid represented by the following general formula (2). ) (Polymer 14) A polyimide having a repeating structural unit as a basic skeleton is obtained.

[0023]

[Chemical 14] [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. Generally, after the polyamic acid is formed at a low temperature, the above-mentioned method of further thermally or chemically imidizing the polyamic acid is carried out. The polyimide can be obtained by simultaneously performing the generation of the polyamic acid and the thermal imidization reaction at a temperature of 60 to 250 ° C. That is, diamine compound, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, and aromatic dicarboxylic acid anhydride or aromatic After suspending or dissolving a monoamine in an organic solvent, the reaction is performed under heating to simultaneously generate a polyamic acid and dehydrate imidize a polyimide having a repeating unit of the general formula (2) as a basic skeleton. You can also get it.

The polyimide of the present invention obtained by the above-mentioned production method, when subjected to melt molding, is another thermoplastic resin within the range not impairing the object of the present invention, such as polyethylene, polypropylene, polycarbonate, polyarylate, polyamide, Polysulfone, polyether sulfone, polyether ketone, polyphenylene sulfide,
Polyamide imide, polyether imide, modified polyphenylene oxide, other polyimide, etc. can be blended in appropriate amounts according to the purpose.

Further, the following fillers used in ordinary resin compositions may be used to such an extent that the object of the invention is not impaired. That is, graphite, carborundum, silica powder, molybdenum disulfide, wear resistance improvers such as fluororesins, glass fibers, carbon fibers, boron fibers, silicon carbide fibers, carbon whiskers, asbestos, metal fibers,
Reinforcing materials such as ceramic fibers, flame retardant improvers such as antimony trioxide, magnesium carbonate, calcium carbonate, electrical property improvers such as clay and mica, tracking improvers such as asbestos, silica and graphite, barium sulfate, Silica, acid resistance improver such as calcium metasilicate, iron powder, zinc powder, aluminum powder, thermal conductivity improver such as copper powder, other glass beads, glass spheres, talc, diatomaceous earth, alumina, silasbaln, hydration Alumina, metal oxides, colorants and the like.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples.

In the examples, various physical properties were measured by the following methods. Logarithmic viscosity: polyamic acid 0.5 g of polyamic acid was dissolved in 100 ml of N, N-dimethylacetamide and measured at 35 ° C. Polyimide powder 0.5 g of polyimide powder was dissolved by heating in 100 ml of p-chlorophenol / phenol (weight ratio 9/1) mixed solvent, and then measured at 35 ° C. Yellowness index: Measured by a transmission method using an SM color computer (SM-6-IS-2B manufactured by Suga Test Instruments Co., Ltd.) according to JISK-7103. Light transmittance: measured by Shimadzu UV160. Glass transition temperature: DSC (Shimadzu DT-40 series, D
SC-A1M). 5% weight loss temperature: DTA-TG (Shimadzu DT-
40 series, DTG-40M). Melt viscosity, flow starting temperature: Measured by Shimadzu Koka type flow tester (CFT500A).

Example 1 3,3'-diaminodiphenyl sulfone 7.4 in a container equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube.
49 g (0.03 mol) and 47.86 g of N, N-dimethylacetamide were charged, and 2,2-bis (3,4-dicarboxyphenyl) -1,
13.610 g (0.0294 mol) of 1,1,3,3,3-hexafluoropropane dianhydride was added portionwise while paying attention to increase in solution temperature, and the mixture was stirred at room temperature for 4 hours. After that, 0.1777 g of phthalic anhydride (0.001
(2 mol) and charged at room temperature for 24 hours. The polyamic acid thus obtained had an inherent viscosity of 0.40 dl / g and exhibited a good varnish form. After taking a part of the above polyamic acid and casting it on a glass plate, 100 ° C,
The temperature was raised to 200 ° C. and 250 ° C. over 1 hour, and the temperature was maintained for 1 hour. However, the holding time at 250 ° C. is 4 hours. Thus, the thickness is 50.6 μm
A polyimide film of was obtained. The glass transition temperature of this polyimide film was 254.6 ° C, and the 5% weight loss temperature was 508.9 ° C. The yellowness index is 3.0 and the light transmittance at 500 nm is 90.4%.
Met. The thermal oxidative stability of the polyimide film obtained in this example was shown by measuring the change with time of its weight loss rate in air at 350 ° C. The result is shown in Figure 1.
Shown in.

Comparative Example-1 Polyamic acid was obtained in the same manner as in Example-1, except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.43 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-1. The glass transition temperature of this polyimide film was 254.7 ° C., and the 5% weight loss temperature was 507.9 ° C. The yellowness index is 4.2, and the light transmittance at 500 nm is 8
It was 8.9%. The weight loss rate of the polyimide film obtained in this Comparative Example in air at 350 ° C. was measured in the same manner as in Example-1. The results are shown in FIG.
It is shown together with the result of 1. From the results of FIG. 1, it can be seen that the weight reduction rate increases as the holding time becomes longer, and the thermal oxidation stability is inferior to the polyimide film obtained in Example-1.

Example-2 A polyamic acid was obtained in the same manner as in Example-1, except that 7.4490 g of 4,4'-diaminodiphenyl sulfone was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here has an inherent viscosity of 0.56 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 1. The glass transition temperature of this polyimide film is 331.7 ° C., 5%
The weight loss temperature was 511.4 ° C. In addition, yellow
The Ness index was 7.2, and the light transmittance at 500 nm was 87.7%.

Comparative Example-2 A polyamic acid was obtained in the same manner as in Example-2 except that phthalic anhydride was not charged. The polyamic acid thus obtained had an inherent viscosity of 0.60 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-2. The glass transition temperature of this polyimide film was 331.5 ° C., and the 5% weight loss temperature was 510.9 ° C. The yellowness index is 8.5 and the light transmittance at 500 nm is 8
It was 7.7%.

Example-3 A polyamic acid was obtained in the same manner as in Example-1, except that 6.072 g of 3,3'-diaminodiphenyl ether was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here had an inherent viscosity of 0.65 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 1. The glass transition temperature of this polyimide film is 227.6 ° C., 5%
The weight loss temperature was 521.1 ° C. In addition, yellow
The Ness index was 6.3, and the light transmittance at 500 nm was 89.6%.

Comparative Example-3 A polyamic acid was obtained in the same manner as in Example-3 except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.67 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-3. The glass transition temperature of this polyimide film was 227.1 ° C., and the 5% weight loss temperature was 520.9 ° C. The yellowness index is 7.3 and the light transmittance at 500 nm is 8
It was 7.9%.

Example-4 A polyamic acid was obtained in the same manner as in Example-1, except that 6.072 g of 3,4'-diaminodiphenyl ether was used in place of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here had an inherent viscosity of 0.46 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 1. The glass transition temperature of this polyimide film is 259.0 ° C, 5%
The weight loss temperature was 512.4 ° C. In addition, yellow
The Ness index was 14.0, and the light transmittance at 500 nm was 87.9%.

Comparative Example-4 A polyamic acid was obtained in the same manner as in Example-4, except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.52 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-4. The glass transition temperature of this polyimide film was 259.1 ° C., and the 5% weight loss temperature was 512.6 ° C. The yellowness index is 16.2 and the light transmittance at 500 nm is 8
It was 7.9%.

Example-5 A polyamic acid was obtained in the same manner as in Example-1, except that 6.072 g of 4,4'-diaminodiphenyl ether was used in place of 3,3'-diaminodiphenyl sulfone. The polyamic acid thus obtained has an inherent viscosity of 0.87 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 1. The glass transition temperature of this polyimide film is 290.3 ° C, 5%
The weight loss temperature was 517.6 ° C. In addition, yellow
The Ness index was 21.1 and the light transmittance at 500 nm was 89.4%.

Comparative Example-5 A polyamic acid was obtained in the same manner as in Example-5, except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.93 dl / g. A part of the above polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-5. The glass transition temperature of this polyimide film was 290.2 ° C., and the 5% weight loss temperature was 517.6 ° C. The yellowness index is 23.1 and the light transmittance at 500 nm is 8
It was 8.9%.

Example-6 A polyamic acid was obtained in the same manner as in Example-1, except that 6.3675 g of 3,3'-diaminobenzophenone was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here had an inherent viscosity of 0.51 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-1. The glass transition temperature of this polyimide film was 249.3 ° C., and the 5% weight loss temperature was 516.3 ° C. The yellowness index was 6.6 and the light transmittance at 500 nm was 88.9%.

Comparative Example-6 A polyamic acid was obtained in the same manner as in Example-6, except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.53 dl / g. A part of the above polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-6. The glass transition temperature of this polyimide film was 249.3 ° C., and the 5% weight loss temperature was 516.5 ° C. The yellowness index is 7.9, and the light transmittance at 500 nm is 8
It was 5.8%.

Example-7 A polyamic acid was obtained in the same manner as in Example-1, except that 5.9481 g of 4,4'-diaminodiphenylmethane was used instead of 3,3'-diaminodiphenylsulfone. The polyamic acid obtained here had an inherent viscosity of 0.67 dl / g.
Met. Taking part of the above polyamic acid, Example-1
A polyimide film was obtained in the same manner as in. The glass transition temperature of this polyimide film was 286.7 ° C., and the 5% weight loss temperature was 509.2 ° C. The yellowness index was 14.5, and the light transmittance at 500 nm was 88.5%.

Comparative Example-7 Polyamic acid was obtained in the same manner as in Example-7, except that the operation of charging phthalic anhydride was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.73 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-7. The glass transition temperature of this polyimide film was 286.6 ° C., and the 5% weight loss temperature was 509.0 ° C. The yellowness index is 16.1 and the light transmittance at 500 nm is 8
It was 7.6%.

Example-8 As in Example-1, except that instead of phthalic anhydride 2,
3-benzophenone dicarboxylic acid anhydride 0.3027 g
Was used to obtain a polyamic acid. The polyamic acid obtained here had an inherent viscosity of 0.38 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-1. The glass transition temperature of this polyimide film is 253.9 ° C., and the 5% weight loss temperature is 50.
It was 8.7 ° C. The yellowness index was 3.3, and the light transmittance at 500 nm was 89.9%.

Example 9 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3 was placed in a container equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube. 13.3275 g (0.03 mol) of 3-hexafluoropropane dianhydride and N, N
-Introducing 48.13 g of dimethylacetamide, adding 7.3000 g (0.0294 mol) of 3,3'-diaminodiphenyl sulfone in portions at room temperature under a nitrogen atmosphere while paying attention to increase of the solution temperature, and adding it at room temperature. Stir for 4 hours. After that, 0.1777 g of aniline (0.0012
(Mol) and charged at room temperature for 24 hours. The polyamic acid thus obtained had an inherent viscosity of 0.42 dl / g. A part of the polyamic acid was taken, cast on a glass plate, and then heated to 100 ° C., 200 ° C., and 250 ° C. over 1 hour, respectively, and kept at each temperature for 1 hour. However, the holding time at 250 ° C. is 4 hours. Thus, a polyimide film having a thickness of 51.2 μm was obtained.
The glass transition temperature of this polyimide film is 253.9.
℃, 5% weight loss temperature was 507.9 ℃. Also,
The yellowness index was 3.2, and the light transmittance at 500 nm was 90.0%. The thermal oxidative stability of the polyimide film obtained in this example was shown by measuring the change with time of its weight loss rate in air at 350 ° C. The result is shown in FIG.

Comparative Example-8 A polyamic acid was obtained in the same manner as in Example-9, but without the operation of charging aniline. The polyamic acid thus obtained had an inherent viscosity of 0.46 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-9. The glass transition temperature of this polyimide film was 254.5 ° C, and the 5% weight loss temperature was 508.5 ° C. The yellowness index is 4.5, and the light transmittance at 500 nm is 88.8.
%Met. The weight loss rate of the polyimide film obtained in this Comparative Example in air at 350 ° C. was measured in the same manner as in Example-9. The results are shown in FIG. 2 together with the results of Example-9. From the results of FIG. 2, it can be seen that the weight reduction rate increases as the holding time becomes longer, and the thermal oxidation stability is inferior to the polyimide film obtained in Example-9.

Example-10 A polyamic acid was obtained in the same manner as in Example-9 except that 7.4490 g of 4,4'-diaminodiphenyl sulfone was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here has an inherent viscosity of 0.55 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 9. The glass transition temperature of this polyimide film is 331.8 ° C., 5%
The weight loss temperature was 511.5 ° C. In addition, yellow
The Ness index was 7.5, and the light transmittance at 500 nm was 86.2%.

Comparative Example-9 A polyamic acid was obtained in the same manner as in Example-10, but without the operation of charging aniline. The polyamic acid thus obtained had an inherent viscosity of 0.62 dl / g.
A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-10. The glass transition temperature of this polyimide film was 331.4 ° C., and the 5% weight loss temperature was 511.3 ° C. The yellowness index is 9.1 and the light transmittance at 500 nm is 85.
It was 9%.

Example-11 A polyamic acid was obtained in the same manner as in Example-9, except that 5.8871 g of 3,3'-diaminodiphenyl ether was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid obtained here had an inherent viscosity of 0.60 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 9. The glass transition temperature of this polyimide film is 226.9 ° C., 5%
The weight loss temperature was 520.9 ° C. In addition, yellow
The Ness index was 6.2, and the light transmittance at 500 nm was 89.3%.

Comparative Example-10 A polyamic acid was obtained in the same manner as in Example-11, but without the operation of charging aniline. The polyamic acid thus obtained had an inherent viscosity of 0.65 dl / g.
A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-11. The glass transition temperature of this polyimide film was 227.0 ° C., and the 5% weight loss temperature was 520.0 ° C. The yellowness index is 7.8 and the light transmittance at 500 nm is 88.
It was 0%.

Example-12 A polyamic acid was obtained in the same manner as in Example-9, except that 5,8871 g of 3,4'-diaminodiphenyl ether was used instead of 3,3'-diaminodiphenylsulfone. The polyamic acid thus obtained had an inherent viscosity of 0.47 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 9. The glass transition temperature of this polyimide film is 259.3 ° C, 5%
The weight loss temperature was 512.5 ° C. In addition, yellow
The Ness index was 14.0, and the light transmittance at 500 nm was 88.0%.

Comparative Example-11 A polyamic acid was obtained in the same manner as in Example-12, but without the operation of charging aniline. The polyamic acid obtained here had an inherent viscosity of 0.54 dl / g.
A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-12. The glass transition temperature of this polyimide film was 258.9 ° C., and the 5% weight loss temperature was 512.5 ° C. The yellowness index is 15.9, and the light transmittance at 500 nm is 8
It was 7.7%.

Example-13 A polyamic acid was obtained in the same manner as in Example-9, except that 5,8871 g of 4,4'-diaminodiphenyl ether was used instead of 3,3'-diaminodiphenyl sulfone. The polyamic acid thus obtained has an inherent viscosity of 0.87 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 9. The glass transition temperature of this polyimide film is 290.3 ° C, 5%
The weight loss temperature was 517.5 ° C. In addition, yellow
The Ness index was 20.9, and the light transmittance at 500 nm was 89.0%.

Comparative Example-12 A polyamic acid was obtained in the same manner as in Example-13, except that the operation of charging aniline was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.90 dl / g.
A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-13. The glass transition temperature of this polyimide film was 290.2 ° C, and the 5% weight loss temperature was 517.5 ° C. The yellowness index is 22.1 and the light transmittance at 500 nm is 8
It was 8.2%.

Example-14 A polyamic acid was obtained in the same manner as in Example-9, except that 6.2402 g of 3,3'-diaminobenzophenone was used instead of 3,3'-diaminodiphenylsulfone. The polyamic acid thus obtained had an inherent viscosity of 0.49 dl / g. A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-9. The glass transition temperature of this polyimide film was 248.3 ° C., and the 5% weight loss temperature was 515.3 ° C. The yellowness index was 6.5, and the light transmittance at 500 nm was 89.0%.

Comparative Example-13 A polyamic acid was obtained in the same manner as in Example-14 except that the operation of charging aniline was not performed. The polyamic acid thus obtained had an inherent viscosity of 0.53 dl / g.
A part of the polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-14. The glass transition temperature of this polyimide film was 249.3 ° C., and the 5% weight loss temperature was 515.5 ° C. The yellowness index is 7.4 and the light transmittance at 500 nm is 85.
It was 5%.

Example-15 A polyamic acid was obtained in the same manner as in Example-9 except that 5.9481 g of 3,3'-diaminodiphenylmethane was used instead of 3,3'-diaminodiphenylsulfone. The polyamic acid obtained here had an inherent viscosity of 0.67 dl / g.
Met. Taking a part of the above polyamic acid, Example-9
A polyimide film was obtained in the same manner as in. The glass transition temperature of this polyimide film was 286.3 ° C., and the 5% weight loss temperature was 509.3 ° C. The yellowness index was 14.5, and the light transmittance at 500 nm was 88.5%.

Comparative Example-14 A polyamic acid was obtained in the same manner as in Example-15, but without the operation of charging aniline. The polyamic acid thus obtained had an inherent viscosity of 0.74 dl / g.
A part of the above polyamic acid was taken and a polyimide film was obtained in the same manner as in Example-15. The glass transition temperature of this polyimide film was 286.3 ° C., and the 5% weight loss temperature was 509.5 ° C. The yellowness index is 17.1 and the light transmittance at 500 nm is 8
It was 8.5%.

Example-16 A polyamic acid was obtained in the same manner as in Example-9, except that 0.1298 g of o-toluidine was used instead of aniline. The polyamic acid obtained here had an inherent viscosity of 0.39 dl /
It was g. Taking a part of the above polyamic acid,
A polyimide film was obtained in the same manner as in 9. The glass transition temperature of this polyimide film is 254.2 ° C, 5%
The weight loss temperature was 508.5 ° C. In addition, yellow
The Ness index was 3.2, and the light transmittance at 500 nm was 89.5%.

Example 17 In a container equipped with a stirrer, a thermometer, a reflux condenser, a water fractionator and a nitrogen inlet tube, 7,3'-diaminodiphenylsulfone 7.449 g (0.03 mol), 2, 2-bis (3,4-dicarboxyphenyl) -1,1,1,3
3,3-hexafluoropropane dianhydride 12.794
4 g (0.0288 mol), phthalic anhydride 0.3555
g (0.0024 mol), 20 g of toluene, and 80.97 g of m-cresol were charged, and the mixture was heated to 150 ° C. with stirring under a nitrogen atmosphere. Then, the mixture was reacted at 150 ° C. for 4 hours. During this time, distillation of about 1.0 ml of water was confirmed. After completion of the reaction, the mixture was cooled to room temperature, discharged into about 1 l of methanol, and then the polyimide powder was filtered off. After washing this polyimide powder with methanol, it was dried under reduced pressure.
3 g (98.9%) of polyimide powder was obtained. The polyimide powder thus obtained had an inherent viscosity of 0.35 dl / g. The glass transition temperature of this polyimide powder is 252.9.
℃, 5% weight loss temperature was 509.7 ℃. Also,
The melt viscosity of this polyimide powder at 370 ° C. is 4250 p.
The melt flow starting temperature was 320 ° C. The weight reduction rate of the polyimide powder obtained in this example is 350 ° C.,
The retention time in air was changed and measured. The result is shown in Figure 3.
Shown in.

Comparative Example-15 In the same manner as in Example-17, but without performing the operation of charging phthalic anhydride, 19.2 g (98.3%) of polyimide powder was obtained. The polyimide powder thus obtained had an inherent viscosity of 0.38 dl / g. The glass transition temperature of this polyimide powder is 253.8 ° C., and the 5% weight loss temperature is 51
It was 0.0 ° C. In addition, this polyimide powder 370 ℃
Melt viscosity was 4420 poise, and the melt flow starting temperature was 320 ° C. The weight reduction rate of the polyimide powder obtained in this comparative example was measured in the same manner as in Example-17. 0
The results are shown in FIG. 3 together with the results of Example-17. From the results of FIG. 3, it can be seen that the weight reduction rate increases as the holding time becomes longer, and the thermal oxidation stability is inferior to the polyimide powder obtained in Example-17.

Example-18 2,2-bis (3,4-dicarboxyphenyl) -1,1,1 was placed in a container equipped with a stirrer, a thermometer, a reflux condenser, a water fractionator and a nitrogen inlet tube. , 3,3,3-Hexafluoropropane dianhydride 13.3275 g (0.03 mol), 3,3'-diaminodiphenyl sulfone 7.15
10 g (0.0288 mol), aniline 0.2235 g
(0.0024 mol), 20 g of toluene, and 81.91 g of m-cresol were charged, and the temperature was raised to 150 ° C. with stirring under a nitrogen atmosphere. After that, at 150 ℃ 4
Reacted for hours. During this period, distillation of about 0.9 ml of water was confirmed. After completion of the reaction, the mixture was cooled to room temperature, discharged into about 1 l of methanol, and then the polyimide powder was filtered off. This polyimide powder was washed with methanol and dried under reduced pressure to give 19.4.
g (98.9%) of polyimide powder was obtained. The polyimide powder thus obtained had an inherent viscosity of 0.38 dl / g. The glass transition temperature of this polyimide powder is 254.1.
℃, 5% weight loss temperature was 510.2 ℃. Also,
The melt viscosity of this polyimide powder at 370 ° C. is 4200 p.
The melt flow starting temperature was 315 ° C. The weight reduction rate of the polyimide powder obtained in this example is 350 ° C.,
The retention time in air was changed and measured. The result is shown in Figure 4.
Shown in.

Comparative Example-16 In the same manner as in Example-18, but without performing the operation of charging aniline, 19.3 g (98.4%) of polyimide powder was obtained. The polyimide powder obtained here had an inherent viscosity of 0.40 dl / g. The glass transition temperature of this polyimide powder is 255.0 ° C., and the 5% weight loss temperature is 509.
It was 6 ° C. The melt viscosity of this polyimide powder at 370 ° C. is 4200 poise, and the melt flow starting temperature is 3
It was 15 ° C. The weight reduction rate of the polyimide powder obtained in this comparative example was measured in the same manner as in Example-18. The result is shown in FIG. 4 together with the result of Example-18. From the results of FIG. 4, it can be seen that the weight reduction rate increases as the holding time becomes longer, and the thermal oxidation stability is inferior to the polyimide powder obtained in Example-18.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

By the method of the present invention, it is possible to provide a polyimide that is excellent in colorless transparency and has excellent heat resistance that the original polyimide has.

[Brief description of drawings]

FIG. 1 is a diagram in which the weight loss rate of a film of the polyimide obtained in Example 1 and Comparative Example 1 in air at 350 ° C. was measured.

FIG. 2 is a diagram in which the weight loss rate of the polyimide films obtained in Example 9 and Comparative Example 8 in air at 350 ° C. was measured.

FIG. 3 is a diagram in which the weight loss rate of the polyimide films obtained in Example 17 and Comparative Example 15 in air at 350 ° C. was measured.

FIG. 4 is a diagram in which the weight loss rate of the polyimide films obtained in Example 18 and Comparative Example 16 in air at 350 ° C. was measured.

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

Claims (6)

[Claims] 1. A polymer molecule end is represented by the following general formula (1) (Chemical Formula 1): Or the following general formula (5) Z-NH ₂ (5) [wherein Y and Z each have 6 to 15 carbon atoms, and are a monocyclic aromatic group, a condensed polycyclic aromatic group, and an aromatic group. Represents a group selected from the group consisting of non-condensed polycyclic aromatic groups linked directly or by a bridging member to each other, Y represents a divalent group, and Z represents a monovalent group. ] The following general formula (2) (Chemical Formula 2) capped with an aromatic dicarboxylic anhydride or an aromatic monoamine represented by the following formula: [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. ] A colorless transparent polyimide having good thermal stability and having a repeating structural unit represented by the following as a basic skeleton. 2. The following general formula (3) (Chemical Formula 3): [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. ] And a diamine compound represented by the following formula (4) (Chemical Formula 4): A tetracarboxylic acid dianhydride represented by 2,2
-Bis (3,4-dicarboxyphenyl) -1,1,
1,3,3,3-hexafluoropropane dianhydride,
0.001-1.0 per mol of this diamine compound
The molar ratio of the general formula (1) (Chemical formula 5) [In the formula, Y has a carbon number of 6 to 15, and is a monocyclic aromatic group, a condensed polycyclic aromatic group, or a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a crosslinking member. A divalent group selected from the group consisting of group groups] is reacted in the presence of an aromatic dicarboxylic acid anhydride represented by the general formula (2) (Chemical Formula 6) [In the formula, X represents SO ₂ , O, CO, CH ₂ and / or S. ] A method for producing a colorless transparent polyimide having a repeating structural unit represented by the following as a basic skeleton and good thermal stability. 3. A tetracarboxylic acid dianhydride represented by the above general formula (4), that is, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3. -The hexafluoropropane dianhydride and the diamine compound represented by the above general formula (3) in a molar ratio of 0.9 to 1.0 per 1 mol of the tetracarboxylic dianhydride, the tetracarboxylic acid dianhydride Reacted in the presence of 0.001 to 1.0 mole ratio of the aromatic monoamine represented by the above general formula (5) per 1 mole of the anhydride, represented by the above general formula (2). A method for producing a colorless and transparent polyimide having a repeating structural unit as a basic skeleton and having good thermal stability. 4. A polyimide film containing the polyimide according to claim 1. 5. A polyamic acid which is a precursor of the polyimide according to claim 1. 6. A varnish containing the polyamic acid according to claim 5.