JPH04233944A - Production of polyimide - Google Patents

Abstract

PURPOSE:To obtain the subject polyimide excellent in thermal stability and melt flow properties and capable of keeping at high temperatures for a long period without reducing its moldability and workability. CONSTITUTION:With (A) 1mol diamine [e.g. bis(4-(3-aminophenoxy) phenyl) methane] represented by formula I (X is direct bond, 1-10C divalent hydrocarbon, etc.; Y1 to Y4 are H, lower alkyl, etc.), (B) 0.9-1mol tetracarboxylic dianhydride (e.g. ethylenetetracarboxylic dianhydride) shown by formula II (R is >=2C aliphatic group, etc.), (C) 0.01-1mol dicarboxylic anhydride (e.g. phthalic anhydride) represented by formula III (Z is divalent group selected from monocyclic aromatic group, etc.) and (D) 0.001-1mol aromatic monoamine (e.g. aniline) represented by formula IV (Z' is univalent group selected from monocyclic aromatic group, etc.) are polymerized in an organic solvent (e.g. N,N- dimethylformamide) to obtain the objective polyimide shown by formula V.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to polyimides for melt molding. More specifically, the present invention relates to a method for producing polyimide having good thermal stability and excellent moldability.

0002

[Prior Art] Polyimide, which is conventionally obtained by the reaction of tetracarboxylic dianhydride and diamine, has not only high heat resistance but also excellent mechanical strength and dimensional stability, as well as flame retardancy and electrical insulation properties. It is used in fields such as electrical and electronic equipment, aerospace equipment, and transportation equipment, and is expected to be widely used in fields that require heat resistance in the future.

[0003] Various polyimides exhibiting excellent properties have been developed. However, even if it has excellent heat resistance, it does not have a clear glass transition temperature, so it must be processed using methods such as sintering when used as a molding material, and although it has excellent processability, it does not have a clear glass transition temperature. However, it had both advantages and disadvantages in terms of performance, such as having a low glass transition temperature, being soluble in halogenated hydrocarbons, and being unsatisfactory in terms of heat resistance and solvent resistance.

On the other hand, the present inventors have previously developed a polyimide of the following formula (Chemical formula 6) which has excellent mechanical properties, thermal properties, electrical properties, solvent resistance, etc., and has heat resistance.

[0005]

[C6]

[wherein, where Y1 to Y4 each independently represent a group selected from the group consisting of hydrogen, a lower alkyl group, a lower alkoxy group, chlorine or bromine, and R has 2 carbon atoms.
From the above aliphatic groups, cycloaliphatic groups, monocyclic aromatic groups, fused polycyclic aromatic groups, and non-fused polycyclic aromatic groups in which aromatic groups are interconnected directly or through a bridge member. represents a tetravalent group selected from the group consisting of: ] We have discovered a polyimide having a repeating unit represented by
78, JP 62-68817, JP 62-8602
1, JP-A-62-235381, JP-A-63-1280
25 etc.). The above polyimide is a new heat-resistant resin that has many good physical properties.

However, although the above-mentioned polyimide exhibits excellent fluidity and is a polyimide with good processability, it is inferior to engineering plastics such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polysulfone, and polyphenylene sulfide. Then, although the above-mentioned polyimide is far superior in heat resistance and other properties, as the molecular weight increases, the melt fluidity decreases, and the moldability is still inferior to the above-mentioned engineering plastics.

[0008]

[Problems to be Solved by the Invention] The purpose of the present invention is to, in addition to the excellent properties inherently possessed by polyimide, also have good thermal stability and excellent melt flowability, so that moldability does not deteriorate even when kept at high temperatures for a long time. Our goal is to provide a polyimide that does not.

[0009]

[Means for Solving the Problems] The present inventors have conducted extensive research to solve the above problems, and as a result, have achieved the present invention. That is, the present invention provides a method for producing polyimide in which a diamine and a tetracarboxylic dianhydride are reacted and the resulting polyamic acid is thermally or chemically imidized.

1) The diamine has the following formula (Chemical formula 7)

[C7]

[wherein, In the formula, Y1 to Y4 each independently represent a group selected from the group consisting of hydrogen, a lower alkyl group, a lower alkoxy group, chlorine, or bromine. ] is a diamine represented by

2) Tetracarboxylic dianhydride has the following formula (
8)

[Chemical formula 8]

[In the formula, R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group, a fused polycyclic aromatic group, or an aromatic group in which the aromatic groups are mutually connected directly or through a bridge member. Represents a tetravalent group selected from the group consisting of linked non-fused polycyclic aromatic groups. ] is a tetracarboxylic dianhydride represented by

3) Furthermore, the reaction is expressed by the following formula (Chemical formula 9)

[Chemical formula 9]

[In the formula, Z is from the group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. Represents a selected divalent group. ] and the following formula (Chemical formula 10)

[0016]

[Chemical formula 10]

[In the formula, Z' is a group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, or a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. represents a monovalent group selected from 4) The amount of tetracarboxylic dianhydride is 0.9 to 1.0 molar ratio per 1 mole of diamine, and the amount of dicarboxylic anhydride is is 0.001 to 1.0 per mole of diamine
molar ratio, and the amount of aromatic monoamine is diamine 1
The following formula (Chemical formula 11) has a molar ratio of 0.001 to 1.0 per mole

[0018]

[Chemical formula 11]

[In the formula, X, Y1, Y2, Y3, Y4 and R are the same as above. ] This is a method for producing a polyimide having good thermal stability and having a repeating unit represented by the following as a basic skeleton.

The diamines represented by formula (1) used in the method of the present invention include bis[4-(3-aminophenoxy)phenyl]methane, 1,1-bis[4-(3
-aminophenoxy)phenyl]ethane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane,
2-[4-(3-aminophenoxy)phenyl]-2-
[4-(3-aminophenoxy)-3-methylphenyl]propane, 2,2-bis[4-(3-aminophenoxy)-3-methylphenyl]propane, 2-[4-(3
-aminophenoxy)phenyl]-2-[4-(3-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(3-aminophenoxy)-
3,5-dimethylphenyl]propane, 2,2-bis[
4-(3-aminophenoxy)phenyl]butane, 2,
2-bis[4-(3-aminophenoxy)phenyl]-
1,1,1,3,3,3-hexafluoropropane, 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, bis[4-(3-aminophenoxy)phenyl] ] Sulfone, etc., may be used alone or in combination of two or more.

[0021] Note that there is no problem in replacing a part of the above diamine with another diamine as long as the good physical properties of the polyimide used in the method of the present invention are not impaired.

Examples of diamines that can be used as partial substitutes include m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis(3-
aminophenyl)ether, (3-aminophenyl)(
4-aminophenyl) ether, bis (4-aminophenyl) ether, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis ( 3-aminophenyl) sulfoxide, (3
-aminophenyl)(4-aminophenyl) sulfoxide, bis(4-aminophenyl) sulfoxide, bis
(3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4 '
-diaminobenzophenone, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4
-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 1
,2-bis[4-(4-aminophenoxy)phenyl]
Ethane, 2,2-bis[4-(4-aminophenoxy)
phenyl]propane, 2,2-bis-[4-(4-aminophenoxy)phenyl]butane, 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,
4-bis[4-(3-aminophenoxy)benzoyl]
Examples include benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, and the like.

[0023] Furthermore, the formula (chemical formula 2) used in the method of the present invention
) Examples of the tetracarboxylic dianhydride include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic dianhydride, 1,1- Screw (2
,3-dicarboxyphenyl)ethane dianhydride, bis(
2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2
, 2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl) )-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoro Propane dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2'3,3
'-benzophenonetetracarboxylic dianhydride, 3,3
'4,4'-biphenyltetracarboxylic dianhydride, 2
, 2'3,3'-biphenyltetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis(3, 4-dicarboxyphenyl) sulfone dianhydride, 4,4'-(p-phenylenedioxy)
Diphthalic dianhydride, 4,4'-(m-phenylenedioxy)diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetra Carboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-
Perylenetetracarboxylic dianhydride, 2,3,6,7-
Anthracenetracarboxylic dianhydride, 1,2,7,
8-phenanthrenetetracarboxylic dianhydride, etc., and these tetracarboxylic dianhydrides may be used alone or in combination
It is used by mixing more than one species.

Furthermore, the formula (3) used in the method of the present invention
) Examples of dicarboxylic acid monoanhydrides include phthalic anhydride, 2,3-benzophenone dicarboxylic anhydride, 3,4-benzophenone dicarboxylic anhydride,
2,3-Dicarboxyphenylphenyl ether anhydride, 3,4-dicarboxyphenylphenyl ether anhydride, 2,3-biphenyldicarboxylic anhydride, 3,4-
Biphenyldicarboxylic anhydride, 2,3-dicarboxyphenylphenyl sulfone anhydride, 3,4-dicarboxyphenylphenyl sulfone anhydride, 2,3-dicarboxyphenylphenyl sulfide anhydride, 3,4-dicarboxyphenylphenyl Sulfide anhydride, 1,2-
naphthalene dicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride, 1,8-naphthalene dicarboxylic anhydride, 1,2-anthracene dicarboxylic anhydride, 2,
Examples include 3-anthracenedicarboxylic anhydride and 1,9-anthracenedicarboxylic anhydride, which may be used alone or in combination of two or more.

[0025] Furthermore, the formula (Chemical formula 4) used in the method of the present invention
) Examples of aromatic monoamines represented by aniline, o-toluidine, m-toluidine, p-toluidine, 2,3-xylidine, 2,4-xylidine, 2,5-
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-phenetidine, m-phenetidine, p-phenetidine, o-aminobenzaldehyde, m-aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzo trifluoride, m-aminobenzotrifluoride, p-aminobenzotrifluoride, 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-aminophenyl phenyl sulfide, 3-aminophenyl phenyl sulfide, 4-aminophenyl phenyl sulfide,
2-aminophenyl phenyl sulfone, 3-aminophenyl phenyl sulfone, 4-aminophenyl phenyl sulfone, α-naphthylamine, β-naphthylamine, 1
-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1-naphthol, 5-amino-1-naphthol
Naphthol, 5-amino-2-naphthol, 7-amino-2-naphthol, 8-amino-1-naphthol, 8
-amino-2-naphthol, 1-aminoanthracene,
Examples include 2-aminoanthracene and 9-aminoanthracene.

The molar ratio of diamine, tetracarboxylic dianhydride and dicarboxylic anhydride, and aromatic monoamine used in the method of the present invention is as follows:
Tetracarboxylic dianhydride is 0.9 to 1.0 mol, dicarboxylic anhydride is 0.001 to 1.0 mol,
The amount of aromatic monoamine is 0.001 to 1.0 mol.

In the production of polyimide, it is common practice to adjust the ratio of tetracarboxylic dianhydride to aromatic diamine in order to adjust the molecular weight of the polyimide produced. In the method of the present invention, the molar ratio of tetracarboxylic dianhydride is 0.9 to 1.0 in order to obtain a polyimide with good melt flowability.

Further, the dicarboxylic acid anhydride and the aromatic monoamine to be coexisted have a ratio of 0.001 to 1 with respect to the diamine.
．． An amount of 0 molar ratio is used. If the molar ratio is less than 0.001, thermal stability at high temperatures and good moldability, which are the objectives of the present invention, cannot be obtained. Moreover, if the molar ratio is more than 1.0, the mechanical properties will deteriorate. The preferred usage amount is 0.0
The molar ratio is 1 to 0.5. Although the reaction method is not particularly limited, it is preferable to carry out the reaction in an organic solvent.

Examples of the organic solvent used in this reaction include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, and N,N-dimethylformamide.
-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,
Examples include phenol, m-cresol, p-cresol, p-chlorophenol, anisole, and the like. Also,
These organic solvents may be used alone or in combination of two or more.

[0030] The method of adding and reacting the starting materials diamine, tetracarboxylic dianhydride, dicarboxylic acid anhydride, and aromatic monoamine to an organic solvent in the method of the present invention is as follows: 1) Diamine and tetracarboxylic dianhydride 2) A method in which dicarboxylic anhydride is added to the diamine, the reaction is continued, and then an aromatic monoamine is added. 3) Diamine, tetracarboxylic dianhydride, and dicarboxylic anhydride are simultaneously added and reacted, and then an aromatic monoamine is added, the reaction is continued, and the aromatic monoamine is added and the reaction is continued. A method of adding a group monoamine and further reacting, etc.
Any addition or reaction may be used.

[0031] The reaction temperature is 0 to 250°C. It is usually carried out at a temperature of 100°C or less. The reaction pressure is not particularly limited, and the reaction can be carried out at normal pressure. Although the reaction time varies depending on the type of diamine, tetracarboxylic dianhydride, dicarboxylic anhydride, and aromatic monoamine solvent used and the reaction temperature, 4 to 24 hours is usually sufficient.

Through such a reaction, the following formula (Chemical formula 12)
Polyimide acid is produced using the repeating unit as a basic skeleton.

[0033]

[Chemical formula 12]

[In the formula, X, Y1, Y2, Y3, Y4 and R are the same as above. ]This polyamic acid is 100
A corresponding polyimide having a repeating unit of the following formula (Chemical formula 13) as a basic skeleton can be obtained by heat dehydration at ~400°C or by chemical imidization using a commonly used imidizing agent such as triethylamine and acetic anhydride. can get.

[0035]

[Chemical formula 13]

[In the formula, X, Y1, Y2, Y3, Y4 and R are the same as above. ] Generally, after producing polyamic acid at a low temperature, it is further thermally or chemically imidized. But 60 to 2
Polyimide can also be obtained by simultaneously performing the production of polyamic acid and the thermal imidization reaction at a temperature of 50°C.

That is, diamine, tetracarboxylic dianhydride, and aromatic dicarboxylic anhydride are suspended or dissolved in an organic solvent and then reacted under heating to simultaneously produce polyamic acid and dehydrate and imidize it. A method in which the reaction is continued by adding an aromatic monoamine. A method in which a diamine or a tetracarboxylic dianhydride is suspended or dissolved in an organic solvent and then reacted under heating, and then a dicarboxylic anhydride or an aromatic monoamine is further added to continue the reaction. Alternatively, the repeating unit of the above (Chemical formula 13) can be obtained by suspending or dissolving diamine, tetracarboxylic dianhydride, dicarboxylic anhydride, or aromatic monoamine in an organic solvent and then carrying out the reaction under heating. It is also possible to obtain a polyimide having it as a skeleton.

When the polyimide of the present invention is subjected to melt molding, other thermoplastic resins such as polyethylene, polypropylene, polycarbonate, polyarylate, polyamide, polysulfone, polyether sulfone, polyether ketone, etc. may be used as long as the purpose of the present invention is not impaired. , polyphenylene sulfide, polyamideimide, polyetherimide, modified polyphenylene oxide, etc., may be blended in appropriate amounts depending on the purpose. Furthermore, the following fillers used in ordinary resin compositions may be used to the extent that the purpose of the invention is not impaired.

That is, wear resistance improvers such as graphite, carborundum, silica powder, molybdenum disulfide, and fluororesins, glass fibers, carbon fibers, boron fibers, silicon carbide fibers, carbon whiskers, asbestos, metal fibers, and ceramic fibers. Reinforcing agents such as antimony trioxide,
Flame retardant improvers such as magnesium carbonate and calcium carbonate; electrical property improvers such as clay and mica; anti-tracking agents such as asbestos, silica and graphite;
Acid resistance improvers such as barium sulfate, silica, calcium metasilicate, thermal conductivity improvers such as iron powder, zinc powder, aluminum powder, copper powder, other glass beads, glass bulbs, talc, diatomaceous earth, alumina, shirasu balloon, water Japanese alumina,
These include metal oxides and colorants.

[0040]

[Examples] The present invention will be specifically explained below using Examples and Comparative Examples. Example 1 368 g (1.0 mol) of 4,4'-bis(3-aminophenoxy)biphenyl and 5215 g of N,N-dimethylacetamide were placed in a reaction vessel equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube. 211.46 g (0.97 mol) of pyromellitic anhydride was added in portions under a nitrogen atmosphere at room temperature while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours.

To this polyamic acid solution was added 13.3 g (0.09 mol) of phthalic anhydride under a nitrogen atmosphere at room temperature, and the mixture was further stirred for 2 hours. Thereafter, 12.6 g (0.135 mol) of aniline was added to this polyamic acid solution, and stirring was continued for 2 hours.

Next, 404 g (4 moles) of triethylamine and 306 g (3 moles) of acetic anhydride were added dropwise to this solution. Approximately 1 hour after the completion of the dropping, yellow polyimide powder began to precipitate. The mixture was further stirred at room temperature for 10 hours and filtered.

[0043] Further, dispersion and washing in methanol, separation by filtration, 1
It was dried at 80° C. for 2 hours to obtain 545 g of polyimide powder. This polyimide powder had a glass transition temperature of 256°C and a melting point of 389°C (according to DSC; the same applies hereinafter).

Further, the logarithmic viscosity of this polyimide powder is 0.
It was 53 dl/g. Here, the logarithmic viscosity is a value measured at 35° C. using a mixed solvent of parachlorophenol:phenol (weight ratio 90:10) at a concentration of 0.5 g/100 ml.

Using the polyimide powder obtained in this example, a Koka type flow tester (manufactured by Shimadzu Corporation, CFT-50) was used.
0), repeated measurements of melt viscosity were performed using an orifice with a diameter of 0.1 cm and a length of 1 cm. After maintaining the temperature at 420° C. for 5 minutes, it was extruded at a pressure of 100 kg/cm 2 . A test was conducted five times in a row in which the obtained strand was crushed and further extruded under the same conditions. Figure 1 shows the relationship between the number of repetitions and melt viscosity. Even when the number of repetitions increases, there is almost no change in melt viscosity, indicating good thermal stability.

Comparative Example 1 529 g of polyimide powder was obtained in exactly the same manner as in Example 1, except that phthalic anhydride and aniline were not reacted. The logarithmic viscosity of the obtained polyimide powder is 0
．． It was 52 dl/g.

Using this polyimide powder, repeated melt viscosity tests were conducted using a flow tester in the same manner as in Example 1, and the results shown in FIG. 1 were obtained. As the number of repetitions increased, the melt viscosity increased, and compared to the polyimide obtained in Example 1, the polyimide was inferior in thermal stability.

Comparative Example 2 536 g of polyimide powder was obtained in exactly the same manner as in Example 1, except that the reaction with aniline was not performed. The logarithmic viscosity of the obtained polyimide powder was 0.53 dl/g. Using this polyimide powder, repeated melt viscosity tests were conducted using a flow tester in the same manner as in Example 1, and the results shown in FIG. 1 were obtained. Even when the number of repetitions is increased, there is almost no change in the melt viscosity, and the thermal stability is good, but the melt viscosity is higher than that of the polyimide powder of Example 1, and the moldability is inferior.

Example 2 Into the same apparatus as in Example 1, 400 g (1.0 mol) of bis[4-(3-aminophenoxy)phenyl]sulfide was added.
8.88 g (0.06 mol) of phthalic anhydride and 211 g (0.97 mol) of pyromellitic dianhydride were added in a nitrogen atmosphere at room temperature, taking care not to increase the solution temperature. The mixture was added while stirring and stirred at room temperature for about 20 hours. Next, 5.6 g (0.06 mol) of aniline was added to this polyamic acid solution, and the mixture was further stirred for 2 hours.

Next, 404 g (4 moles) of triethylamine and 306 g (3 moles) of acetic anhydride were added dropwise to this solution. After stirring for 20 hours, a pale yellow slurry was obtained. This slurry was filtered and washed with methanol at 180°C.
The mixture was dried under reduced pressure for 8 hours to obtain 582 g of pale yellow polyimide powder. This polyimide powder had a glass transition temperature of 235° C. and a logarithmic viscosity of 0.49 dl/g.

The molding stability of the polyimide obtained in this example was measured by changing the residence time in the cylinder of a flow tester. The temperature was 320°C and the pressure was 100 kg/cm2. The results are shown in Figure 2. Even if the residence time in the cylinder becomes longer, the melt viscosity hardly changes, indicating good thermal stability.

Comparative Example 3 A pale yellow polyimide powder was obtained in exactly the same manner as in Example 2, except that phthalic anhydride and aniline were not used. The glass transition temperature of polyimide powder is 235°C, and the logarithmic viscosity is 0.49.
It was dl/g. As in Example 2, the residence time in the cylinder of the flow tester was changed and the melt viscosity was measured. As the residence time became longer, the melt viscosity increased, and compared to the polyimide obtained in Example 2, the melt viscosity increased. The stability was poor.

Comparative Example 4 A pale yellow polyimide powder was obtained in exactly the same manner as in Example 2, except that aniline was not used. The polyimide powder had a glass transition temperature of 235° C. and a logarithmic viscosity of 0.49 dl/g. As in Example 2, the residence time in the cylinder of the flow tester was changed and the melt viscosity was measured.As the residence time increased, there was almost no change in the melt viscosity, and the thermal stability was good. It can be seen that the moldability is higher than that of the polyimide powder of Example 2, and that the moldability is inferior.

Example 3 Into the same apparatus as in Example 1, 396 g (1 mol) of bis[4-(3-aminophenoxy)phenyl]ketone and bis(
3,4-dicarboxyphenyl)ether dianhydride 30
0.7g (0.97mol), phthalic anhydride 8.88g (
0.06 mol) and 4000 g of m-Gresol were charged, and the temperature was increased by heating under a nitrogen atmosphere while stirring. At around 120°C, it became a brown transparent homogeneous solution. 150℃
When the mixture was heated to a temperature of 100% and continued stirring, yellow polyimide powder began to precipitate in about 20 minutes. After further stirring under heating for 2 hours, 5.6 g (0.06 mol) of aniline was added, and stirring was continued for another 2 hours.

[0055] Thereafter, it was filtered to obtain polyimide powder. This polyimide powder was washed with methanol and acetone and then dried under reduced pressure at 180° C. for 8 hours to obtain 663 g of polyimide powder. The logarithmic viscosity of this polyimide powder is 0.51d
l/g, and the glass transition temperature was 201°C. Example 1
Similarly, when the melt viscosity was measured by repeatedly extruding each sample using a flow tester at a temperature of 280° C. and a pressure of 100 kg/cm 2 , almost no change in the melt viscosity was observed depending on the number of measurements. The results are shown in Figure 3.

Examples 4 to 6 Polyimide powders were obtained by carrying out the same operations as in Example 1, except that the amounts of pyromellitic anhydride, phthalic anhydride, and aniline were changed as shown in Table 1. The glass transition temperature, melting point, and logarithmic viscosity of the obtained polyimide powder are also shown in Table 1. Next, these polyimide powders were repeatedly extruded using a flow tester in the same manner as in Example 1, and the melt viscosity of each powder was measured, and almost no change in viscosity was observed depending on the number of measurements. The results are shown in Figure 3.

[0057]

[Table 1]

[0058]

[Effects of the Invention] According to the method of the present invention, it has excellent mechanical properties, thermal properties, electrical properties, and solvent resistance, is heat resistant, is thermally stable for a long time, and has excellent moldability. We can provide excellent polyimide.

[Brief explanation of the drawing]

FIG. 1 is an example diagram showing the relationship between the number of melting cycles and the melt viscosity of the polyimide of the present invention.

FIG. 2 is an example diagram showing the relationship between the residence time in the cylinder of the polyimide flow tester of the present invention and the melt viscosity.

FIG. 3 is an example diagram showing the relationship between the number of melting cycles and the melt viscosity of the polyimide of the present invention.

Claims (1)

[Claims] Claim 1: A method for producing polyimide, which comprises reacting a diamine with a tetracarboxylic dianhydride and thermally or chemically imidizing the resulting polyamic acid, wherein: 1) the diamine has the following formula (Chemical formula 1): ) [Formula 1] [wherein, Y1 to Y4 each independently represent a group selected from the group consisting of hydrogen, a lower alkyl group, a lower alkoxy group, chlorine, or bromine. ] is a diamine represented by
2) The tetracarboxylic dianhydride has the following formula (Chemical formula 2) [Chemical formula 2] [In the formula, R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group,
Represents a tetravalent group selected from the group consisting of a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. . [In the formula, Z is a monocyclic aromatic group, a fused polycyclic aromatic group, Represents a divalent group selected from the group consisting of non-fused polycyclic aromatic groups in which aromatic groups are interconnected directly or through a bridge member. ] and the following formula (Chemical formula 4) [Chemical formula 4] [In the formula, Z' is a monocyclic aromatic group, a fused polycyclic aromatic group,
It represents a monovalent group selected from the group consisting of non-fused polycyclic aromatic groups in which aromatic groups are interconnected directly or through a bridge member. 4) The amount of tetracarboxylic dianhydride is 0.9 to 1.0 molar ratio per 1 mole of diamine, and the amount of dicarboxylic anhydride is is 0.001 to 1.0 per mole of diamine
molar ratio, and the amount of aromatic monoamine is diamine 1
The following formula (Chemical formula 5) has a molar ratio of 0.001 to 1.0 per mole [Chemical formula 5] [In the formula, X, Y1, Y2, Y3, Y4 and R are the same as above. ] A method for producing a polyimide having good molding stability and having a repeating unit represented by the following as a basic skeleton.