JPH0218419A - Production of polyimide excellent in thermal stability - Google Patents

Abstract

PURPOSE:To obtain the subject polyimide excellent in molding processability by reacting a diaminobenzophenone with a specific tetracarboxylic acid anhydride and dicarboxylic acid anhydride and imidating the resultant polyamic acid. CONSTITUTION:(A) One mol 3,3'-diaminobenzophenone expressed by formula I is reacted with (B) 0.9-1.0mol tetracarboxylic acid dianhydride expressed by formula II (R is tetrafunctional groups, such as >=2C aliphatic or monocyclic aromatic group) and (C) 0.001-1.0mol dicarboxylic acid anhydride expressed by formula III (Z is bifunctional group, such as monocyclic aromatic or condensed polycyclic aromatic group) to provide a polyamic acid, which is then thermally or chemically imidated to afford (D) the objective polyimide having recurring units expressed by formula IV as a basic skeleton.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to polyimide resins for melt molding.

More specifically, the present invention relates to a method for producing polyimide having good thermal stability and excellent moldability.

(Conventional technology) Polyimide, which has traditionally been 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. Therefore, 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.

Various polyimides have been developed that exhibit superior properties.

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. , low glass transition temperature,
Moreover, it is soluble in halogenated hydrocarbons, and its performance has both advantages and disadvantages, such as unsatisfactory heat resistance and solvent resistance.

On the other hand, Proger et al.
A polyimide having a repeating unit represented by the following formula (IV) (wherein R is the same as above) has been discovered as a polyimide having excellent electrical properties, solvent resistance, etc., and heat resistance. (U.S. Pat. No. 4,065,345) The above polyimide is a novel heat-resistant resin with many good physical properties.

However, the above polyimide exhibits excellent fluidity,
Although polyimide has good processability, its melt viscosity is higher than that of engineering plastics that can be normally extruded and injection molded, making injection and extrusion molding difficult. Due to the current situation, the only option was to use the casting method.

(Problems to be Solved by the Invention) In addition to the excellent properties that polyimide inherently possesses, the purpose of the present invention is to provide polyimide with excellent thermal stability and no deterioration in moldability even when kept at high temperatures for long periods of time. Our goal is to provide polyimide.

[Means for solving problems]

The present inventors conducted extensive research to solve the above problems and achieved the present invention.

That is, the present invention provides a method for producing polyimide in which diamine and tetracarboxylic dianhydride are reacted and the obtained polyamic acid is thermally or chemically imidized, in which (i) the diamine has the following formula ( I) A diamine represented by (b) The tetracarboxylic dianhydride is represented by the following formula (If) (wherein R is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, a monocyclic aromatic group) (represents a tetravalent group selected from the group consisting of a 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) It is a tetracarboxylic dianhydride, and (c)
Furthermore, the reaction is represented by the following formula (III), where 2 is a monocyclic aromatic group, a fused polycyclic aromatic group, or a non-fused polycyclic aromatic group in which the aromatic groups are interconnected directly or through a bridge member. It is carried out in the presence of a dicarboxylic acid anhydride represented by (2) representing a divalent group selected from the group consisting of the following groups, and the amount of tetracarboxylic dianhydride (d) is 0. 9 to 1.0 molar ratio, and the amount of dicarboxylic acid anhydride is 0.001 to 1.0 per mole of diamine.
It is a molar ratio.

This is a method for producing a polyimide with good thermal stability, which has a repeating unit represented by the following formula (IV) (wherein R is the same as above) as a basic skeleton.

The polyimide used in the method of the present invention is a diamine represented by the formula (I), that is, 3.3°-diaminobenzophenone. There is no problem in substituting a part of the diamine with another diamine.

Examples of diamines that can be used as partial substitutes include m-phenylenediamine, 0-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, 34
'-Diaminobenzophenone, 4,4'-diaminobenzophenone, bis(4-(4-aminophenoxy)phenylcomethane, 1,1-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)phenylcobutane, 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)phenylkoketone, 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)benzene, 1.3-bis(
4-(3-aminophenoxy)benzoyl]benzene,
bis(4-(3aminophenoxy)phenylcomethane,
1,1-bis(4-(3-aminophenoxy)phenyl]ethane, 2,2-bis(4-(3-aminophenoxy)phenyl)propane, 2-(4-(3-aminophenoxy)phenyl)- 2-C4-(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)phenylcobutane, 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°41
-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)phenylkoketone, bis(4-(3-aminophenoxy)phenyl) sulfide, bis( 4-(3-aminophenoxy)-3-methoxyphenyl fusulfide, (4
-(3-aminophenoxy)phenyl)(4-(3-aminophenoxy)-3,5-dimethoxyphenyl]sulfide, bis[4-[3-aminophenoxy)-3,
5-dimethoxyphenyl] sulfide, bis(4-(3
-7minophenoxy)phenyl]sulfone and the like.

Examples of the tetracarboxylic dianhydride represented by formula (II) used in the method of the present invention include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, and cyclopentanetetracarboxylic dianhydride. dianhydride, pyromellitic dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl) carboxyphenyl)ethane dianhydride, 2,2-bis(
3,4-dicarboxyphenyl)propanihydride, 2
．． 2-bis(2,3-dicarboxyphenyl)propanihydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropd
Panni anhydride, 2.2-bis(2゜3-dicarboxyphenyl')-1,1,1,3,3,3-hexafluoropropanni anhydride, 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,
Bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfide anhydride, 4.4'-( p-phenylenedioxy)cyphthalic dianhydride, 414'-(m-phenylenedioxy)cyphthalic dianhydride, 2.3.6.7-naphthalenetetracarboxylic dianhydride, 1.4.5. 8-Naphthalenetetracarboxylic dianhydride, 1.2.5.6-naphthalenetetracarboxylic 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, etc.,
These tetracarboxylic dianhydrides may be used alone or in combination of two or more. Particularly preferred is 3.3'
, 4,4°-benzophenonetetracarboxylic dianhydride.

Further, examples of the dicarboxylic anhydride represented by formula (III) used in the method of the present invention include phthalic anhydride, 2,3-benzophenone dicarboxylic anhydride, 3.4-benzophenone dicarboxylic anhydride,
-benzophenone dicarboxylic anhydride, 2.3-dicarboxyphenyl phenyl ether anhydride, 3.4-
Dicarboxyphenyl phenyl ether anhydride, 2.
3-biphenyldicarboxylic anhydride, 3.4-biphenyldicarboxylic anhydride, 2.3-dicarboxyphenyl phenyl sulfonic anhydride, 3.4-dicarboxyphenyl phenyl sulfonic anhydride, 2.3-dicarboxyphenyl Phenyl sulfide anhydride, 3.4
-dicarboxyphenyl phenyl sulfide anhydride, 1,2-naphthalene dicarboxylic anhydride, 2,3-naphthalene dicarboxylic anhydride, 1,8-naphthalene dicarboxylic anhydride, 1,2-anthracene dicarboxylic anhydride, 2 , 3-tenthracenedicarboxylic anhydride, 1.
Examples include 9-anthracenedicarboxylic anhydride,
These may be used alone or in combination of two or more.

The molar ratio of amine, tetracarboxylic dianhydride and dicarboxylic anhydride used in the method of the present invention is 0.9 for tetracarboxylic dianhydride per mole of diamine.
The amount of dicarboxylic acid anhydride is 0.001 to 1.0 mol.

In the production of polyimide, it is common practice to adjust the ratio of diamine to tetracarboxylic dianhydride in order to control the molecular weight of the produced polyimide. In order to obtain a good polyimide, the molar ratio of tetracarboxylic dianhydride to diamine is 0.9 to 1.0.

Further, the dicarboxylic acid anhydride coexisting is used in an amount of 0.001 to 1.0 molar ratio to the diamine.

If the molar ratio is less than 0.001, the thermal stability at high temperatures, which is the objective of the present invention, cannot be obtained, and 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.

There is no particular restriction on the reaction method for obtaining the polyimide of the present invention,
Although known methods may be used, it is preferred to carry out 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-methyl caprolactam, 1,2-dimethoxyethane, bis(
2-methoxyethyl)ether, 1.2-bis(2-methoxyethoxy)ethane, bis(2-(2-methoxyethoxy)ethyl)ether, tetrahydrofuran, 1,
Examples include 3-dioxane, 1,4-dioxane, pyridine, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphoramide, phenol, m-cresol, p-cresol, p-chlorophenol, anisole, etc. . Further, these organic solvents may be used alone or in combination of two or more. - The method of adding and reacting the starting materials diamine, tetracarboxylic dianhydride, and dicarboxylic anhydride to an organic solvent in the method of the present invention includes (a) reacting the diamine with the tetracarboxylic dianhydride; (b) A method in which dicarboxylic anhydride is added to the diamine and the reaction is continued; (b) A method in which tetracarboxylic dianhydride is added after the diamine is reacted; ) Diamine, tetracarboxylic dianhydride, and dicarboxylic anhydride may be added and reacted simultaneously; any addition or reaction may be used.

The reaction temperature is 0°C to 250°C, but it is usually carried out at a temperature of 60°C or less.

The reaction pressure is not particularly limited, and the reaction can be carried out at normal pressure.

The reaction time varies depending on the diamine, tetracarboxylic dianhydride, dicarboxylic anhydride used, type of solvent, and reaction temperature, but usually 4 to 24 hours is sufficient.

Through such a reaction, a polyamic acid having a repeating unit of the following formula (V) as a basic skeleton is produced.

This polyamic acid is dehydrated by heating at 100 to 400'C or chemically imidized using a commonly used imidizing agent, such as triethylamine and acetic anhydride, so that the repeating unit of the following formula (TV) is used as a basic skeleton. A corresponding polyimide having the following properties is obtained.

Generally, after producing polyamic acid at low temperature,
Further, this is thermally or chemically imidized. However, polyimide can also be obtained by simultaneously performing the production of polyamic acid and the thermal imidization reaction at a temperature of 60°C to 250°C.

That is, after suspending or dissolving diamine, tetracarboxylic dianhydride, and aromatic dicarboxylic acid anhydride in an organic solvent, a reaction is carried out under heating to simultaneously produce polyamic acid and dehydrate and imidize it. A polyimide having the repeating unit of the above formula (IV) as a basic skeleton can also be obtained.

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, polyphenylene may be used as long as the purpose of the present invention is not impaired. It is also possible to blend sulfide, polyamideimide, polyetherimide, modified polyphenylene oxide, etc. 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. Abrasion improving materials, glass fibers, carbon fibers,
Reinforcing materials such as boron fibers, silicon carbide fibers, carbon whiskers, asbestos, metal fibers, ceramic fibers, flame retardant improving materials such as antimony dioxide, magnesium carbonate, calcium carbonate, electrical property improving materials such as clay and mica, asbestos , tracking resistance improvers such as silica and graphite, acid resistance improvers such as barium sulfate, silica, and calcium metasilicate, thermal conductivity improvers such as iron powder, zinc powder, aluminum powder, copper powder, and other glass beads and glass balls. , talc, diatomaceous earth, alumina, shirasu balloon, hydrated alumina, metal oxides, colorants, etc.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

(Example 1) 212 g of 3;3°-diaminobenzophenone was placed in a reaction vessel equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube.
(I,0 mol) and 2970 g of III,N-dimethylacetamide were charged, and 3,3
312 g (0.97 mol) of 4,4'-benzophenonetetracarboxylic dianhydride was added in portions 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, 22.2 g (0.15 mol) of phthalic anhydride was added under a nitrogen atmosphere at room temperature, and an additional 1
After stirring for several hours, 202 g (2 moles) of triethylamine and 306 g (3 moles) of acetic anhydride were then added dropwise to this solution.About 1 hour after the completion of the dropwise addition, yellow polyimide powder began to precipitate. The mixture was further stirred at room temperature for 10 hours and filtered. Further, dispersion washing in methanol, filtration separation, 1
It was dried at 80° C. for 2 hours to obtain 487 g of polyimide powder. The glass transition temperature of this polyimide powder was 250°C, and the melting point was 298°C (according to OSC. The same applies hereinafter).
Further, the logarithmic viscosity of this polyimide powder was 0.52d17g.

Here, the logarithmic viscosity is parachlorophenol:phenol (
Using a mixed solvent with a weight ratio of 90:1G), a concentration of 0.5
This is a value measured at 35°C using g/100+d solvent.

Using the polyimide powder obtained in this example, the diameter was 0.
．． Repeated measurements of the melt viscosity were carried out using an orifice with a length of 1 (I1, tell). After being kept at a temperature of 380 ° C. for 5 minutes, it was extruded at a pressure of 100 kg/cd. The obtained strand was crushed, Furthermore, extrusion tests were conducted five times in a row under the same conditions.

The relationship between the number of repetitions and melt viscosity is shown in FIG.

Even when the number of repetitions increases, there is almost no change in melt viscosity, indicating good thermal stability.

(Comparative Example 1) 464 g of polyimide powder was obtained in exactly the same manner as in Example 1, except that the reaction with phthalic anhydride was not performed.

The logarithmic viscosity of the obtained polyimide powder was 0.52 a/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 increases, the melt viscosity increases, and Example 1
The thermal stability was inferior to that of the polyimide obtained in .

(Example 2) Into the same apparatus as in Example 1, 212 g (I, 0 mol) of 3.3''-diaminobenzophenone and 2970 g of dimethylacetamide were charged, and the mixture was heated at room temperature under a nitrogen atmosphere at 8°8
8 g (0.06 mol) of phthalic anhydride and 312 g
(0.97 mol) of 3.3',4,4'-benzophenonetetracarboxylic dianhydride was added while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours.

Next, 202 g (2 moles) of triethylamine and 306 g (3 moles) of acetic anhydride were added dropwise to this solution. 2
After stirring for 0 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 485 g of pale yellow polyimide powder. The glass transition temperature of this polyimide powder is 250°
The C1 melting point was 298'' and the C2 logarithmic viscosity was 0.50 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 380° C. and the pressure was 100 kg/aa. Second
The results are shown in the figure. Even if the residence time in the cylinder becomes longer, the melt viscosity hardly changes, indicating good thermal stability.

(Comparative Example 2) A pale yellow polyimide powder was obtained in exactly the same manner as in Example 2, except that phthalic anhydride was not used.

The glass transition temperature of the polyimide powder was 250°C and the logarithmic viscosity was 0.50 dl/g. As in Example 2, when the residence time in the flow tester cylinder was changed and the melt viscosity was measured, the melt viscosity increased as the residence time increased, indicating that the polyimide obtained in Example 2 was more thermally stable. It was of inferior quality.

(Example 3) Into the same apparatus as in Example 1, 212 g (I mol) of 3.3"-diaminohensiphenone and 315.6 g of 3.3", 4.4"-benzophenone tetracarboxylic dianhydride were added.
(0°98 mol), phthalic anhydride 5.92g (0.0
4 mol) and 2970 g of m-cresol were charged, and the temperature was increased by heating under a nitrogen atmosphere while stirring. 12
It became a brown transparent homogeneous solution at around 0'C. 150°C
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, the mixture 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 485 g of polyimide powder.

The logarithmic viscosity of this polyimide powder is 0.57 dl/g,
The glass transition temperature was 251°C and the melting point was 298°C.

Same as Example 1, but temperature 400°C2 pressure 100kg
When the melt viscosity was measured by repeatedly extruding each sample using a flow tester at /d, almost no change in the melt viscosity was observed depending on the number of measurements. The results are shown in Figure 3.

〔Effect of the invention〕

According to the method of the present invention, a polyimide that 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. can do.

[Brief explanation of the drawing]

FIGS. 1 and 3 are diagrams showing the relationship between the number of melting cycles and the melt viscosity of the polyimide of the present invention, and FIG. 2 is an example diagram showing the relationship between the residence time in the flow tester cylinder and the melt viscosity of the polyimide of the present invention. Figure 3: Number of repetitions Q: polyimide obtained in practical example 1 Δ: polyimide obtained in comparative example 1 O: polyimide obtained in practical example 2 △: polyimide obtained in comparative example 2 Number of repetitions Chart Residence time in cylinder (min)

Claims (1)

[Claims] 1. In a method for producing polyimide, which involves reacting a diamine with a tetracarboxylic dianhydride and thermally or chemically imidizing the obtained polyamic acid, (a) the diamine is one of the following: 3,3'-diaminobenzophenone is represented by the formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) Tetracarboxylic dianhydride is represented by the following formula (II) ▲ Numerical formulas, chemical formulas, There are tables etc.▼(II) (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. . ) is a tetracarboxylic dianhydride represented by (c)
Furthermore, the reaction is expressed by the following formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (In the formula, Z is a monocyclic aromatic group, a fused polycyclic aromatic group, or an aromatic group directly or a represents a divalent group selected from the group consisting of non-fused polycyclic aromatic groups interconnected by (d) in the presence of a dicarboxylic acid anhydride represented by The amount of acid dianhydride is 0.9 to 1.0 molar ratio per mol of diamine, and the amount of dicarboxylic acid anhydride is 0.001 to 1.0 per mol of diamine.
It is a molar ratio. A method for producing polyimide with good thermal stability, which has a repeating unit represented by the following formula (IV) ▲Mathematical formula, chemical formula, table, etc.▼(IV) (in the formula, R is the same as before) as a basic skeleton.