JP2606912B2 - Method for producing polyimide having good thermal stability - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyimide resin for melt molding. More specifically, the present invention relates to a method for producing a polyimide having good thermal stability and excellent moldability.

[Prior art] Conventionally, a polyimide obtained by a reaction between a tetracarboxylic dianhydride and a diamine has excellent mechanical strength and dimensional stability, in addition to its high heat resistance, and has both flame retardancy and electrical insulation properties. In addition, they are used in fields such as electric and electronic equipment, aerospace equipment, and transport equipment, and are expected to be widely used in fields where co-heat resistance is required in the future.

Conventionally, various polyimides exhibiting excellent characteristics have been developed.

However, even if it has excellent heat resistance, it does not have a clear glass transition temperature, so if it is used as a molding material, it must be processed using a method such as sintering, and it has excellent workability. It has a low glass transition temperature, is soluble in halogenated hydrocarbons, is not satisfactory in terms of heat resistance and solvent resistance, and has advantages and disadvantages in performance.

On the other hand, the present inventor has previously described the following formula (IV) as a polyimide having excellent mechanical properties, thermal properties, electrical properties, solvent resistance, etc. and having heat resistance. (Wherein, R represents 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 condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which the aromatic groups are connected to each other directly or by a bridge member. . A polyimide having a repeating unit represented by the following formula was found (JP-A-62-50372). The above-mentioned polyimide is a novel heat-resistant resin having many good physical properties.

However, although the above-mentioned polyimide shows excellent fluidity and is a polyimide having good processability, if it is kept at a high temperature for a long time (for example, during injection molding, if it stays in a cylinder for a long time at a high temperature), The fluidity of the molten resin gradually decreases, and as a result, the moldability decreases.

[Problems to be Solved by the Invention] An object of the present invention is to provide an excellent polyimide which, in addition to the excellent properties inherent to polyimide, has good thermal stability and does not deteriorate in moldability even when kept at a high temperature for a long time. It is to provide a manufacturing method.

[Means for Solving the Problems] The present inventors have conducted intensive research to solve the above problems, and have completed the present invention. That is, the present invention provides: And (b) an aromatic diamine represented by the following formula (II): (Wherein, R represents a tetravalent group described below); and (C) the following formula (III) Z-NH ₂ (III) (wherein Z represents 1 (D) the amount of the aromatic diamine is 0.9 to 1.0 mole ratio per mole of tetracarboxylic dianhydride, and the amount of the aromatic monoamine is 0.1 mole per mole of carboxylic dianhydride
Reacting at a molar ratio of 001 to 1.0, characterized by the formula (IV) (Wherein R is as defined in formula (II).) Production of a polyimide having good thermal stability, comprising a repeating unit represented by the formula: wherein the terminal of the polymer is a group of formula (IV-a) Is the way.

(In the formula, R and Z are as defined above.) As the aromatic diamine represented by the formula (I) used in the method of the present invention, 1,4-bis [4- (3-aminophenoxy) ) Benzoyl] benzene and / or 1,3-
Bis [4- (3-aminophenoxy) benzoyl] benzene.

In addition, as long as the good physical properties of the polyimide obtained by the method of the present invention are not impaired, one of the above aromatic diamines may be used.
There is no problem in using a part in place of another diamine.

Examples of aromatic diamines that can be used as a partial substitute include, for example, 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) sulfide (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, 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, 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'-tetra Bromobiphenyl, 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-aminephenoxy) -3 , 5-dimethoxyphenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, and the like, and these may be used alone or as a mixture of two or more.

Further, R of the tetracarboxylic dianhydride represented by the formula (II) used in the method of the present invention is as follows: Is mentioned. These tetracarboxylic dianhydrides are used alone or in combination of two or more.

Further, Z of the aromatic monoamine represented by the formula (III) used in the present invention is as follows. Is mentioned.

The molar ratio of the tetracarboxylic dianhydride, the aromatic diamine and the aromatic monoamine used in the method of the present invention is 1 mol per mol of the tetracarboxylic dianhydride, 0.9 to 1.0 mol of the aromatic diamine, 0.00 for monoamines
It is a ratio of 1 to 1.0 mol.

In the production of polyimide, it is customary to adjust the ratio of tetracarboxylic dianhydride to aromatic diamine in order to adjust the molecular weight of the resulting polyimide.
In the method of the present invention, in order to obtain a polyimide having good melt flowability, the molar ratio of the aromatic diamine to the tetracarboxylic dianhydride is from 0.9 to 1.0.

The co-existing aromatic monoamine is used in an amount of 0.001 to 1.0 mol based on tetracarboxylic dianhydride. If the amount is less than 0.001 mol, the thermal stability at a high temperature intended for the present invention cannot be obtained. If it is 0.1 mol or more, the mechanical properties deteriorate. The preferred amount is 0.01 to 0.
The ratio is 5 mol.

In the method of the present invention, all known methods for producing polyimide can be used, but it is particularly preferable to carry out the reaction in an organic solvent.

Examples of the organic solvent used in this method include N, N-dimethylformamide, N, N-dimethylacetamide, N, N
-Diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl ) Ether, 1,2-bis (2-methoxyethoxy) ethane, bis {2- (2-methoxyethoxy) ethyl} ether, tetrahydrofuran, 1,3-dioxane, 1,4-
Dioxane, pyridine, picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethyl urea, hexamethyl phosphoramide, phenol, m-cresol, p-
Cresol, p-chlorophenol, anisole and the like can be mentioned. These organic solvents may be used alone or in combination of two or more.

The method of adding tetracarboxylic dianhydride, aromatic diamine, aromatic monoamine to the organic solvent in the method of the present invention and reacting the same includes (a) reacting tetracarboxylic dianhydride with aromatic diamine, (B) a method in which an aromatic monoamine is added and the reaction is continued, (b) a method in which an aromatic monoamine is added to a tetracarboxylic dianhydride to cause a reaction, and then an aromatic diamine is added and the reaction is further continued; Any addition method may be employed, such as a method of simultaneously adding and reacting a carboxylic dianhydride, an aromatic diamine, and an aromatic monoamine.

The reaction is carried out in a temperature range from 0 ° C to 250 ° C. Usually, it is performed at a temperature of 60 ° C. or less.

 The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure.

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

By such a reaction, a polyamic acid comprising a repeating unit represented by the following formula (V) is produced.

(Wherein R is the same as described above). The polyamic acid is dehydrated by heating to 100 to 400 ° C. or chemically imidized using a commonly used imidizing agent, for example, triethylamine and acetic anhydride. A corresponding polyimide comprising the repeating unit of IV) is obtained.

(Wherein R is the same as above.) In general, after forming polyamic acid at a low temperature,
Further, it is thermally or chemically imidized. However, at a temperature of 60 ° C. to 250 ° C., polyimide can be obtained by simultaneously performing the polyamic acid generation and the thermal imidization reaction. That is, after the aromatic diamine, tetracarboxylic dianhydride, aromatic monoamine is suspended or dissolved in an organic solvent, the reaction is carried out under heating, and the polyamic acid generation and the dehydration imidization are simultaneously performed to form the above. A polyimide comprising the repeating unit of the formula (IV) can also be obtained.

In addition, without using an organic solvent, a method of obtaining a polyimide by mixing a tricarboxylic acid dianhydride, an aromatic diamine, and an aromatic monoamine, and treating the mixture in the presence or absence of a dehydrating agent, or the like. Is also used.

When subjecting the polyimide of the present invention to melt molding, other thermoplastic resins within a range that does not impair the purpose of the present invention, for example,
An appropriate amount of polyethylene, polypropylene, polycarbonate, polyarylate, polyamide, polysulfone, polyethersulfone, polyetherketone, polyphenylenesulfide, polyamideimide, polyetherimide, modified polyphenylene oxide, etc. can be blended in an appropriate amount depending on the purpose. . Further, the following fillers and the like used in ordinary resin compositions may be used to the extent that the object of the invention is not impaired. That is, graphite,
Abrasion resistance improvers such as carborundum, silica powder, molybdenum disulfide, and fluororesin; reinforcing materials such as glass fiber, carbon fiber, boron fiber, silicon carbide fiber, carbon whisker, asbestos, metal fiber, and ceramic fiber; and trioxide Flame retardant improver such as antimony, magnesium carbonate, calcium carbonate, etc .; electric property improver such as clay and mica; tracking improver such as asbestos, silica, graphite, etc .; acid resistance such as barium sulfate, silica, calcium metasilicate, etc. Improver, thermal conductivity improver such as iron powder, zinc powder, aluminum powder, copper powder, etc., other glass beads, glass spheres, talc, diatomaceous earth, alumina, silasbarn, hydrated alumina, metal oxides, coloring agents, etc. It is.

[Examples] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 1 In a reactor equipped with a stirrer, a reflux condenser and a nitrogen inlet tube, 218 g (1.0 mol) of pyromellitic anhydride and N, N-
3940 g of dimethylacetamide was charged and 1,3-bis [4-
(3-Aminophenoxy) benzoyl] benzene 477.5 g
(0.955 mol) was added portionwise at room temperature under a nitrogen atmosphere, paying attention to the rise in solution temperature, and the mixture was stirred at room temperature for about 20 hours.

12.6 g (0.135 mol) of aniline was added to this polyamic acid solution at room temperature under a nitrogen atmosphere, and the mixture was further stirred for 1 hour. Next, 202 g (2 mol) of triethylamine and 306 g (3 mol) of acetic anhydride were added dropwise to the solution, and the solution was added at room temperature.
After stirring for 10 hours, a pale yellow slurry was obtained. The slurry was separated by filtration, and further dispersed and washed in methanol.
After drying at 0 ° C. for 2 hours, 638 g of polyimide powder was obtained. The glass transition temperature of this polyimide powder was 235 ° C. The logarithmic viscosity of this polyimide powder was 0.53 dl / g.
This logarithmic viscosity is a value measured at 35 ° C. using a mixed solvent of parachlorophenol and phenol (weight ratio 90:10) with a solvent having a concentration of 0.5 g / 100 ml.

Using the polyimide powder obtained in this example, with a Koka type flow tester (Shimadzu Corporation, CFT-500), diameter 0.1c
The melt viscosity was repeatedly measured using an orifice having a length of 1 cm and a length of 1 cm. After keeping at 330 ℃ for 5 minutes, 100kg / c
Extruded at a pressure of m ² . Crush the obtained strand,
Further, the test of extruding under the same conditions was performed five times in succession.

FIG. 1 shows the relationship between the number of repetitions and the melt viscosity. Even if the number of repetitions increases, there is almost no change in the melt viscosity, indicating that the thermal stability is good.

Comparative Example 1 An experiment was performed in exactly the same manner as in Example 1 except that the operation of reacting aniline was not performed, and 620 g of a polyimide powder was obtained.

The logarithmic viscosity of the obtained polyimide powder was 0.53 dl / g. Using this polyimide powder, a repetition test of the melt viscosity was performed by 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 the thermal stability was inferior to that of the polyimide obtained in Example 1.

Example 2 In the same apparatus as in Example 1, 294 g (1.0 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and sanilin were added.
Charge 9.3 g (0.1 mol) and 5130 g of dimethylacetamide, and add 475 g (0.95 mol) of 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene at room temperature under a nitrogen atmosphere. While stirring, the mixture was stirred at room temperature for about 20 hours.

Then, to this solution, 202 g (2 mol) of triethylamine and 306 g (3 mol) of acetic anhydride were added dropwise. The mixture was stirred for 20 hours to obtain a pale yellow slurry. The slurry was filtered, washed with methanol, and dried under reduced pressure at 180 ° C. for 8 hours.
05 g of pale yellow polyimide powder was obtained. The glass transition temperature of this polyimide powder was 225 ° C., and the logarithmic viscosity was 0.52 dl / g.

The molding stability of the polyimide obtained in this example was measured by changing the residence time in the cylinder of the flow tester.
The temperature was 330 ° C. and the pressure was 100 kg / cm ² . FIG. 2 shows the results. Even if the residence time in the cylinder becomes longer, the melt viscosity hardly changes, indicating that the thermal stability is good.

Comparative Example 2 An experiment was performed in exactly the same manner as in Example 2 except that aniline was not used, and a pale yellow polyimide powder was obtained.

The glass transition temperature of the polyimide powder is 225 ° C and the logarithmic viscosity is
It was 0.52 dl / g. When the residence time in the flow tester cylinder was changed and the melt viscosity was measured in the same manner as in Example 2, the melt viscosity increased as the residence time became longer, and the heat stability was higher than that of the polyimide obtained in Example 2. It was inferior.

Example 3 In the same apparatus as in Example 1, 451.3 g (0.9025) of 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene was added.
Mol) and bis (4-aminophenyl) ether 9.5 g
(0.0475 mol), 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride 322 g (1.0 mol), aniline 9.3 g
(0.1 mol) and 4500 g of m-cresol were charged, and heated and heated while stirring under a nitrogen atmosphere. After heating to 150 ° C. and continuing stirring for 4 hours, the mixture was cooled, and the reaction product was discharged into methanol and filtered to obtain a 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 718 g of a polyimide powder.

The logarithmic viscosity of this polyamide powder was 0.51 dl / g, and the glass transition temperature was 220 ° C.

As in Example 1, when the melt viscosity was measured by repeatedly extruding with a flow tester at a temperature of 310 ° C. and a pressure of 100 kg / cm ² , the change in the melt viscosity due to the number of measurements was hardly observed. FIG. 3 shows the results.

Comparative Example 3 12.6 g (0.135 mol) of aniline was added to the polyamic acid solution obtained in Example 1 in the same manner as in Example 1, and the mixture was further stirred for 1 hour, and the polyamic acid solution was added to a large amount of ethyl ether. The polyamic acid was separated by precipitation.
After drying the polyamic acid powder thus obtained in a nitrogen stream at 35 ° C., an oven filled with inert gas is used.
The polyimide was treated at 150 ° C. for 3 hours, then at 200 ° C. for 1 hour, and further at 300 ° C. for 3 hours to obtain a polyimide. The logarithmic viscosity of this polyimide was 0.52 dl / g. The thermal stability of this polyimide was evaluated in the same manner as in Example 1. As a result, Example 1 and Comparative Example 1 were evaluated.
Showed almost intermediate values. That is, although improved compared to Comparative Example 1, it was not sufficient, and compared with Example 1, there was a remarkable difference in the repeated melt viscosity, and it was confirmed that the melt viscosity was not endurable.

[Effects of the Invention] According to the method of the present invention, it is excellent in mechanical properties, thermal properties, electrical properties, solvent resistance, heat resistance, thermal stability for a long time, and moldability. An excellent polyimide can be provided.

[Brief description of the drawings]

1 and 3 show the relationship between the number of repetitions of the melting of the polyimide of the present invention and the melt viscosity, and FIG. 2 shows the relationship between the residence time of the polyimide of the present invention in the flow tester cylinder and the melt viscosity.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Yamaguchi 1-1-13-24 Zaimiza, Kamakura City, Kanagawa Prefecture (56) References JP-A-62-50372 (JP, A) JP-A-59-170122 (JP, A) JP 38-5997 (JP, B1)

Claims (1)

(57) [Claims] (1) The following formula (I) And (b) an aromatic diamine represented by the following formula (II): (Where R is Represents a tetravalent group selected from the group consisting of And a tetracarboxylic dianhydride represented by the following formula (III): Z-NH ₂ (III) wherein Z is Represents a monovalent group selected from the group consisting of (D) the amount of the aromatic diamine is 0.9 to 1.0 mole ratio per mole of the tetracarboxylic dianhydride, and the amount of the aromatic monoamine is 1 mole of the tetracarboxylic dianhydride. 0.00 per mole
Reacting at a molar ratio of 1 to 1.0, characterized by the formula (IV) (Wherein R is as defined in formula (II).) Production of a polyimide having good thermal stability, comprising a repeating unit represented by the formula: wherein the terminal of the polymer is a group of formula (IV-a) Method. (In the formula, R and Z are as defined above.)