JP2002249581A - Process for producing polyimide composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a polyimide composite excellent in heat resistance, mechanical characteristics, gas barrier properties, dimensional stability and the like. SOLUTION: The process for producing a polyimide composite comprises the step of polymerizing a diamine component and an acid anhydride component, serving as raw material monomers of a polyimide, in an organic solvent in the presence of a intercalation compound comprising a laminar clay mineral having alkylammonium ions intercalated therein to obtain a polyamic acid solution having the intercalation compound dispersed therein and the step of imidizing the polyamic acid to obtain a polyimide composite, wherein the content of the exchangeable alkali metal ions in the intercalation compound is 500 ppm or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyimide composite, and more particularly, to a method for producing a polyimide composite having excellent heat resistance, mechanical properties, gas barrier properties, dimensional stability, and the like.

[0002]

2. Description of the Related Art Conventionally, polyimide is excellent in heat resistance, mechanical properties, electrical insulation, chemical resistance, etc., so that flexible printed circuit boards, flat cables,
It is widely used as a material in the manufacture of electric and electronic products such as TAB. However, with the phenomenal development of electronics, the demand for smaller, lighter, more functional, more reliable, and lower cost electronic devices is increasing. Is strongly desired.

[0003] In order to respond to such demands by improving the performance of polyimide materials, an interlayer compound in which a layered clay mineral is used as a host and an ionic substance is intercalated with the host is used in the polyimide at the molecular level. A composite dispersed in the same has been proposed. For example, JP-A-4-3395
According to Japanese Patent Publication No. 5 and JP-A-11-349709,
It has been proposed that a polyimide composite is obtained by dispersing an interlayer compound obtained by intercalating a layered clay mineral with an organic onium salt such as an alkyl ammonium ion as a guest in polyimide. However, in such a polyimide composite, since the guest in the intercalation compound is an organic onium salt that is a low molecular weight compound, even in a polyimide composite in which the intercalation compound is dispersed, improvement of properties such as heat resistance is sufficient. Therefore, the reinforcing effect is not satisfactory. Therefore, if the amount of intercalation of the organic onium salt is suppressed, there is a problem that a complex in which the interlayer compound is completely delaminated cannot be obtained. Further, although the obtained composite has an improved elastic modulus, it has a problem that tensile elongation and tensile strength are significantly reduced.

[0004]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to solve the above-mentioned problems in improving the performance of polyimide materials, and as a result, have found that an interlayer formed by intercalating alkylammonium ions into a layered clay mineral is obtained. By setting the amount of exchangeable alkali metal ions of the compound to a predetermined value or less, a diamine component, which is a raw material monomer of the polyimide, and an acid anhydride component are reacted in the presence thereof to form a polyamic acid, and by imidizing this, heat resistance It has been found that not only a polyimide composite having excellent mechanical properties such as elastic modulus, elongation, and strength can be obtained, but also a polyimide composite having excellent balance.

[0005] Accordingly, the present invention provides,
An object of the present invention is to provide a method for producing a polyimide composite having excellent mechanical properties, gas barrier properties, dimensional stability, and the like.

[0006]

According to the present invention, a diamine component and an acid anhydride component, which are raw material monomers for polyimide, are mixed with an organic solvent in the presence of an intercalation compound obtained by intercalating an alkylammonium ion into a layered clay mineral. In the method for producing a polyimide composite comprising: a step of obtaining a polyamic acid solution in which the intercalation compound is dispersed, and a step of obtaining a polyimide composite by imidizing the polyamic acid, There is provided a method for producing a polyimide composite, wherein the amount of exchangeable alkali metal ions is 500 ppm or less.

Further, according to the present invention, there is provided a polyimide composite produced by such a method.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a polyimide composite according to the present invention comprises the steps of: preparing a diamine component and an acid anhydride component as raw material monomers of polyimide in the presence of an intercalation compound obtained by intercalating alkylammonium ions into a layered clay mineral. Polymerizing in an organic solvent to obtain a polyamic acid solution in which the interlayer compound is dispersed, and imidizing the polyamic acid to obtain a polyimide composite; An interlayer compound having an exchangeable alkali metal ion content of 500 ppm or less is used.

In order to obtain an intercalation compound by intercalating an alkylammonium ion into a layered clay mineral, for example, a layered clay mineral is dispersed in an appropriate solvent, and a solution, preferably an aqueous solution of the above alkylammonium ion is added thereto. And, if necessary, mixing and stirring with heating to exchange ions of exchangeable cations (typically sodium ions and magnesium ions) of the layered clay mineral with the above-mentioned alkylammonium ions. Next, the precipitate thus obtained is separated by filtration, washed, dried, and crushed, whereby an intercalation compound obtained by intercalating the alkylammonium ion into the layered clay mineral can be obtained as a powder.

In the present invention, as described above, when intercalating the alkylammonium ion with the layered clay mineral, a solvent is preferably used. As this solvent, a protic solvent such as water or alcohol is preferably used because the layered clay mineral has good dispersibility. The alkylammonium ion is also used as a solution using a protic solvent such as water or alcohol.

The alkylammonium preferably has a main chain composed of a straight or branched carbon chain, but may have a cyclic structure in a part of the main chain.

However, according to the present invention, the alkylammonium ion used preferably has 6 to 18 carbon atoms in the main chain from the viewpoint of the polarity of the organic solvent used in the synthesis of the polyimide. , Hexylamine ion, octylamine ion, decylamine ion,
Dodecylamine ion, tetradecylamine ion, hexadecylamine ion, octadecylamine ion and the like can be mentioned. Such an alkylammonium ion can be prepared, for example, by protonating a corresponding alkylamine with an acid in a solution.

In the present invention, the layered clay mineral as a host for forming an intercalation compound using the alkylammonium ion as a guest includes smectite clay minerals such as montmorillonite, saponite and hectorite, vermiculite, halloysite, and swelling. Although mica and the like can be mentioned, particularly, smectite-based clay minerals are preferably used, and among these, so-called sodium-type smectites in which the exchangeable alkyl alkali metal ion is a sodium ion are easily ion-exchanged with an alkyl ammonium ion. Therefore, it is preferably used.

According to the present invention, the amount of cation exchange of these layered clay minerals is from 50 to 200 meq / min from the viewpoint of the affinity of the obtained interlayer compound for the solvent or polyimide.
Preferably it is in the range of 100 g.

When the exchangeable cation of the layered clay mineral is ion-exchanged with the above-mentioned alkylammonium ion, it is preferable to use the above-mentioned alkylammonium ion in an amount equal to or more than the cation exchange amount of the layered clay mineral.

According to the present invention, in obtaining the intercalation compound in this way, it is necessary that the amount of exchangeable alkali metal ions in the intercalation compound is 500 ppm or less. Here, the method of reducing the exchangeable alkali metal ion content of the obtained intercalation compound to 500 ppm or less is not particularly limited, but, for example, (1) an alkyl excess in excess of the cation exchange content of the layered clay mineral The layered clay mineral is ion-exchanged with ammonium ions to reduce the amount of exchangeable alkali metal ions in the intercalation compound to 500 ppm or less. (2) The ions are exchanged until the amount of exchangeable alkali metal ions in the intercalation compound becomes 500 ppm or less. The exchange operation is performed a plurality of times. (3) At the time of ion exchange, the concentration of the layered clay mineral at the time of ion exchange is adjusted, for example, by using a larger amount of a dispersion medium (eg, water) for the layered clay mineral. , Etc.

The method of quantifying the alkali metal ion in the clay mineral is not particularly limited either, but may be a conventional method. For example, an interlayer compound is dissolved in a strong acid such as hydrofluoric acid, After summing and dilution, the amount can be determined by ion chromatography, IPC emission analysis, or the like.

When the exchangeable alkali metal ion content of the intercalation compound used in the present invention exceeds 500 ppm,
Since the attraction force between the layers in the interlayer compound is still strong, the separation and peeling of the layers are small, and as a result, it is impossible to obtain a polyimide composite having the desired excellent physical properties.

According to the present invention, an alkylammonium ion is thus intercalated into a layered clay mineral to form an intercalation compound, and in the presence thereof, a diamine, which is a raw material monomer of polyimide, is mixed with an organic solvent in an organic solvent. The polycarboxylic acid solution is obtained by polymerizing the tetracarboxylic dianhydride.

The organic solvent used for preparing the above polyamic acid solution may be any aprotic polar solvent generally used for the synthesis of polyimide, and may be, for example, N, N-dimethylacetamide, N-methylpyrrolidone, N, N-methylpyrrolidone. Examples include, but are not limited to, N-dimethylformamide, dimethylsulfoxide, diglyme, and the like. In addition, any other solvent that can be mixed with these can be used in combination.

Polyimide is a resin obtained by obtaining a polyamic acid by a condensation reaction between a tetracarboxylic dianhydride and a diamine, and subjecting the polyamic acid to an imidization reaction (dehydration reaction). As components, p-phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 4,4′-bis (4-aminophenoxy) biphenyl,
1,4'-bis (4-aminophenoxy) benzene, 4,4'-
Diaminodiphenyl sulfone and the like can be mentioned.
On the other hand, examples of the acid anhydride component include pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, and benzophenonetetracarboxylic dianhydride.

In order to obtain a polyamic acid solution in the presence of the above-mentioned intercalation compound, first, the above-mentioned intercalation compound is uniformly dispersed in the above-mentioned organic solvent using an appropriate dispersing means such as a disperser or an ultrasonic disperser. Prepare a dispersion. In this case, it is preferable to disperse the intercalation compound in the organic solvent under heating so as not to exceed the boiling point of the organic solvent used.

Next, the dispersion of the intercalation compound thus prepared is diluted with an appropriate organic solvent, and then charged into a reactor. A diamine component, which is a raw material of polyimide, is added thereto and dissolved. Furthermore, by adding an acid anhydride component,
By mixing and stirring, the above-mentioned diamine component and acid anhydride component are reacted, and thus a polyamic acid solution in which the interlayer compound is uniformly dispersed can be obtained. Here, the ratio between the diamine component and the acid anhydride component is adjusted so as to be substantially equivalent (equimolar amount).

According to the present invention, the polyamic acid is then imidized from the polyamic acid solution thus obtained to obtain a polyimide composite. To obtain a polyimide composite from the polyamic acid, for example, heating the polyamic acid solution, causing a dehydration reaction of the polyamic acid, a thermal method of imidization, and adding a dehydrating agent to the polyamic acid solution, May be used by any of the chemical methods for imidizing the compound.

In the case of the above-mentioned thermal method, the organic solvent is removed from the polyamic acid solution by drying under the condition that imidization does not occur, and then the polyamide is usually subjected to an appropriate heat treatment in a temperature range of 150 to 400 ° C. The imidization by the dehydration reaction of the acid proceeds, and a polyimide composite can be obtained. On the other hand, when using a chemical method, a solution containing a stoichiometric or more dehydrating agent and a catalytic amount of a tertiary amine may be mixed with the polyamic acid solution. As the dehydrating agent, for example, aliphatic or aromatic acid anhydrides such as acetic anhydride and phthalic anhydride are used. Further, as the catalyst,
For example, aliphatic tertiary amines such as triethylamine, and heterocyclic tertiary amines such as pyridine, picoline and isoquinoline are used.

According to the present invention, the mixing ratio (content) of the intercalation compound in the polyimide composite is usually in the range of 2 to 7% by weight of the composite, preferably 2 to 5% by weight.
Range. When the compounding ratio of the intercalation compound is less than 2% by weight, the resulting polyimide composite is poor in the effect of improving the elastic modulus, the coefficient of linear expansion, the tensile strength, the moisture permeability and the like, and when it exceeds 7% by weight. However, since the composite is extremely embrittled and the elongation is significantly reduced, it becomes difficult to handle the film, for example.

Generally, in a layered clay mineral, an alkali metal ion having a positive charge between layers attracts a silicate layer having a negative charge by electrostatic interaction,
The layer is suppressed from being dispersed and peeled. Here, the polyimide composite according to the present invention reacts a diamine component and an acid anhydride component in the presence of an interlayer compound having an exchangeable alkali metal ion content of 500 ppm or less to generate a polyamic acid, It is imidized, as a result of the reduction of the attraction between the layers in the interlayer compound, the silicate layer is completely dispersed, peeled, polyimide having excellent physical properties, that is, not only excellent heat resistance, A polyimide composite having an excellent balance of mechanical properties such as elastic modulus, elongation, and strength can be obtained.

Depending on the purpose, the polyimide composite obtained by the method of the present invention may contain pigment components such as carbon, titanium oxide and boron nitride, a heat stabilizer, an antioxidant, an ultraviolet absorber, and a light stabilizer. Agents, lubricants, plasticizers, antistatic agents, flame retardants and the like can be added.

[0029]

The present invention will be described below with reference to examples together with comparative examples, but the present invention is not limited to these examples.

Example 1 (Preparation of Intercalation Compound Dispersion) 20 g of Kunipia F (montmorillonite in which the exchangeable alkali metal ion is sodium ion, a cation exchange capacity of 119 meq / 100 g, manufactured by Kunimine Industry Co., Ltd.) was added to 400 g of distilled water. In addition, the mixture was stirred and dispersed to prepare a clay dispersion. Separately, 4.4 g of dodecylamine, 2.4 mL of concentrated hydrochloric acid and 100 g of water are uniformly mixed, added to the above-mentioned clay dispersion, and stirred at 80 ° C. for 1 hour, thus performing ion exchange treatment. The precipitated solid was separated by filtration.

After the above-mentioned ion exchange treatment is repeated three times using the cake-like solid obtained in this way, the cake-like solid thus obtained is freeze-dried to remove water, and then crushed in a mortar. Thus, a powdery intercalation compound having a sodium ion content of 80 ppm was obtained. 3 g of this intercalation compound was stirred and dispersed in 90 g of dimethylacetamide (DMAc) at 90 ° C. for 1 hour to obtain a paste-like intercalation compound dispersion.

(Preparation of Polyamic Acid Solution) 16.9 g of the above intercalation compound dispersion, 16.9 g of DMAc and 7.66 g of 4,4'-diaminodiphenyl ether (ODA) were uniformly dispersed and dissolved. This was charged into a glass reactor equipped with a stirrer, and then pyromellitic dianhydride (PMD)
A) 8.34 g was added and polymerized at room temperature for 3 hours to obtain a viscous polyamic acid solution.

(Preparation of Polyimide Composite) The above polyamic acid solution was manually applied on a glass substrate using an applicator, and this was dried in a dryer under a nitrogen stream at 100 ° C. for 1 hour, and then at 150 ° C. for 1 hour. Time, then 2 minutes at 300 ° C
Time, heat drying, heat imidization, thickness 50μ
m was obtained as a polyimide composite film.

Comparative Example 1 (Preparation of Intercalation Compound Dispersion) 20 g of Kunipia F was added to 400 g of distilled water, stirred and dispersed to prepare a clay dispersion. Separately, 4.4 g of dodecylamine, 2.4 m of concentrated hydrochloric acid
L and 100 g of water were uniformly mixed, added to the clay dispersion, and stirred at 80 ° C. for 1 hour.

After the precipitated solid was separated by filtration, the solid was sufficiently washed with warm water. The obtained cake-like solid was freeze-dried to remove water, and then crushed in a mortar to reduce the amount of sodium ions to 5%.
A powdery intercalation compound of 80 ppm was obtained. 3 g of this intercalation compound was stirred and dispersed in 90 g of DMAc at 90 ° C. for 1 hour to obtain a paste-like intercalation compound dispersion.

(Preparation of Polyamic Acid Solution) A polyamic acid solution was obtained in the same manner as in Example 1 using the above-mentioned interlaminar compound dispersion.

(Polyimide Composite) Using the above polyamic acid solution, a polyimide composite film was obtained in the same manner as in Example 1.

Comparative Example 2 (Preparation of Polyamic Acid Solution) ODA was added to 150 g of DMAc.
After dissolving 23.9 g and charging this into a glass reactor equipped with a stirrer, 26.1 g of PMDA was added and the mixture was added at room temperature for 3 hours.
Polymerization was performed for a time to obtain a viscous polyamic acid solution.

(Preparation of Polyamide Alone) Using the above polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1.

Example 2 (Preparation of Intercalation Compound Dispersion) 20 g of Kunipia F was added to 1200 g of distilled water, stirred and dispersed to prepare a clay dispersion. Separately, 8.8 g of dodecylamine, 4.8 concentrated hydrochloric acid
mL and 100 g of water were mixed uniformly, added to the clay dispersion, stirred at 80 ° C. for 1 hour, subjected to ion exchange treatment, and the precipitated solid was separated by filtration.

The cake-like solid thus obtained was freeze-dried to remove water, and then crushed in a mortar to obtain a powdery intercalation compound having a sodium ion content of 410 ppm. 3 g of this intercalation compound was added to dimethylacetamide (DM
Ac) In 90 g, the mixture was stirred and dispersed at 90 ° C. for 1 hour to obtain a paste-like interlayer compound dispersion.

(Preparation of Polyamic Acid Solution) A polyamic acid solution was obtained in the same manner as in Example 1 using the above-mentioned interlaminar compound dispersion.

(Polyimide Composite) A polyimide composite film was obtained in the same manner as in Example 1 using the above polyamic acid solution.

Example 3 (Preparation of Intercalation Compound Dispersion) 20 g of Kunipia F was added to 400 g of distilled water, stirred and dispersed to prepare a clay dispersion. Separately, 2.4 g of hexylamine, 2.4 m of concentrated hydrochloric acid
L and 100 g of water were uniformly mixed, added to the above-mentioned clay dispersion, and stirred at 80 ° C. for 1 hour. Thus, an ion exchange treatment was performed, and a precipitated solid was separated by filtration.

After the above-mentioned ion exchange treatment was repeated three times using the cake-like solid thus obtained, the obtained cake-like solid was freeze-dried to remove water, and then crushed in a mortar. Thus, a powdery intercalation compound having a sodium ion content of 80 ppm was obtained. 3 g of this intercalation compound was added to DMA
In 90 g of c, the mixture was stirred and dispersed at 90 ° C. for 1 hour to obtain a paste-like interlayer compound dispersion.

(Preparation of Polyamic Acid Solution) A polyamic acid solution was obtained in the same manner as in Example 1 using the above-mentioned interlayer compound dispersion.

(Polyimide Composite) A polyimide composite film was obtained in the same manner as in Example 1 using the above polyamic acid solution.

Comparative Example 3 (Preparation of Intercalation Compound Dispersion) 20 g of Kunipia F was added to 400 g of distilled water, stirred and dispersed to prepare a clay dispersion. Separately, 2.4 g of hexylamine, 2.4 m of concentrated hydrochloric acid
L and 100 g of water were uniformly mixed, added to the above-mentioned clay dispersion, and stirred at 80 ° C. for 1 hour, thus performing an ion exchange treatment.

After the precipitated solid was separated by filtration, the solid was sufficiently washed with warm water. After freeze-drying the obtained cake-like solid to remove water, the cake-like solid was crushed in a mortar and the sodium ion content was 9%.
A powdery intercalation compound of 00 ppm was obtained.

3 g of this intercalation compound was added to 90 g of DMAc,
The mixture was stirred and dispersed at 90 ° C. for 1 hour to obtain a paste-like interlayer compound dispersion.

(Preparation of Polyamic Acid Solution) A polyamic acid solution was obtained in the same manner as in Example 1 using the above-mentioned interlayer compound dispersion.

(Polyimide Composite) Using the above polyamic acid solution, a polyimide composite film was obtained in the same manner as in Example 1.

Example 4 (Preparation of Interlayer Compound Dispersion) Kunipia F (20 g) was added to distilled water (400 g), stirred and dispersed to prepare a clay dispersion. Separately, 4.4 g of dodecylamine, 2.4 m of concentrated hydrochloric acid
L and 100 g of water were uniformly mixed, added to the above-mentioned clay dispersion, and stirred at 80 ° C. for 1 hour. Thus, an ion exchange treatment was performed, and a precipitated solid was separated by filtration.

Using the cake-like solid thus obtained, the above-mentioned ion-exchange treatment was repeated three times, and the cake-like solid thus obtained was freeze-dried to remove water, and then crushed in a mortar. Thus, a powdery intercalation compound having a sodium ion content of 80 ppm was obtained. 3 g of this interlayer compound was added to 90 g of N-methyl-2-pyrrolidone (NMP) at 90 ° C.
The mixture was stirred and dispersed for a time to obtain a paste-like interlayer compound dispersion.

(Preparation of Polyamic Acid Solution) 26 g of the above-mentioned intercalated compound dispersion, 64.5 g of NMP and 6.08 g of p-phenylenediamine (PDA) were uniformly dispersed and dissolved, and this was charged into a glass reactor equipped with a stirrer. Next, 16.54 g of 3,3 ′, 4,4′-diphenylethertetracarboxylic dianhydride (BPDA) was added and polymerized at room temperature for 3 hours to obtain a viscous polyamic acid solution.

(Preparation of Polyimide Composite) The above polyamic acid solution was manually applied on a glass substrate using an applicator, and this was dried in a dryer under a nitrogen stream at 100 ° C. for 1 hour and at 150 ° C. for 1 hour. Next, it was heated and dried at 300 ° C. for 2 hours, and thermally imidized to obtain a polyimide composite film having a thickness of 50 μm.

Comparative Example 4 (Preparation of Interlayer Compound Dispersion) A dispersion was prepared by adding 20 g of Kunipia F to 400 g of distilled water, stirring and dispersing. Separately, 4.4 g of dodecylamine, 2.4 mL of concentrated hydrochloric acid
And 100 g of water were uniformly mixed, added to the above dispersion, and stirred at 80 ° C. for 1 hour. After the precipitated solid was separated by filtration 1, the solid was sufficiently washed with warm water. The obtained cake-like solid was freeze-dried to remove water, and then pulverized in a mortar to obtain a powdered organic clay mineral having a sodium ion content of 580 ppm. 3 g of this organically modified clay mineral is 90 g of NMP
The mixture was stirred and dispersed at 90 ° C. for 1 hour in a medium to obtain a paste-like interlayer compound dispersion.

(Preparation of Polyamic Acid Solution) A polyamic acid solution was obtained in the same manner as in Example 4 using the above-mentioned interlayer compound dispersion.

(Polyimide Composite) A polyimide composite film was obtained in the same manner as in Example 4 using the above polyamic acid solution.

Example 5 (Preparation of Intercalation Compound Dispersion) In the same manner as in Example 1, an intercalation compound dispersion was prepared. (Preparation of polyamic acid solution)

37.6 g of the above intercalation compound dispersion and ODA
7.66 g was uniformly dispersed and dissolved, and this was charged into a glass reactor equipped with a stirrer. Then, 8.34 g of pyromellitic dianhydride (PMDA) was added, and the mixture was polymerized at room temperature for 3 hours to give a viscous liquid. A polyamic acid solution was obtained.

(Preparation of Polyimide Composite) A polyimide composite film was obtained in the same manner as in Example 1 using the above polyamic acid solution.

Comparative Example 5 (Preparation of Intercalation Compound Dispersion) In the same manner as in Example 1, an intercalation compound dispersion was prepared.

(Preparation of Polyamic Acid Solution) 5.1 g of the above intercalated compound dispersion, 28.7 g of DMAc, and ODA 7.6
6 g was uniformly dispersed and dissolved, and this was charged into a glass reactor equipped with a stirrer. Then, 8.34 g of pyromellitic dianhydride (PMDA) was added, and the mixture was polymerized at room temperature for 3 hours to obtain a viscous polyamic acid. A solution was obtained.

(Preparation of Polyimide Composite) Using the above polyamic acid solution, a polyimide composite film was obtained in the same manner as in Example 1.

The properties of the polyimide (composite) films obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated as follows. The results are shown in Tables 1 and 2.

(Storage Modulus) Using a dynamic viscoelasticity spectrometer DMS210 (manufactured by Seiko Instruments Inc.), the temperature dispersion was measured in the tensile mode in the range of 30 to 480 ° C. The frequency is 10 Hz and the rate of temperature rise is 5 ° C./min. The storage modulus at 50 ° C. and 400 ° C. was read from the spectrum. (Glass transition temperature) The temperature dispersion of tan δ was measured by a dynamic viscoelasticity spectrum meter, and the temperature showing the maximum value was defined as the glass transition temperature Tg. (Tensile elongation and tensile strength) A polyimide (composite) film is cut into strips (width 5 mm, length 50 mm), and Tensilon UTM-5000 (Toyo Baldwin Co., Ltd.)
Was measured at a temperature of 22 ° C. The distance between the chucks was 50 mm, and the pulling speed was 5 mm / min.

(Linear Expansion Coefficient) Evaluation was performed by TMA method using TMA / SS100 (manufactured by Seiko Denshi Co., Ltd.). The linear expansion coefficient in a temperature range of 50 to 250 ° C. was evaluated at a heating rate of 20 ° C./min. (Moisture permeability) The temperature is 60 ° C and the humidity is 90% by the moisture-permeable cup method.
Was measured under constant temperature and humidity conditions. (Quantification of the amount of sodium ions in the interlayer compound) The interlayer compound was decomposed using a mixture of hydrochloric acid and hydrofluoric acid, neutralized and diluted with water, and then sodium ions were quantified by an IPC emission analysis system.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

According to the method of the present invention, a compound having an exchangeable alkali metal ion content of 500 ppm or less is used as an intercalation compound.
A polyimide composite having excellent mechanical properties, thermal properties, gas barrier properties, etc., and particularly excellent elongation and breaking strength can be obtained.

Claims (3)

[Claims] In the presence of an intercalation compound in which an alkylammonium ion is intercalated into a layered clay mineral, a diamine component and an acid anhydride component, which are raw materials of polyimide, are polymerized in an organic solvent to disperse the intercalation compound. Obtaining a polyamic acid solution, and imidizing the polyamic acid to obtain a polyimide composite, a method for producing a polyimide composite, wherein the amount of exchangeable alkali metal ions of the interlayer compound is 500 ppm or less. A method for producing a polyimide composite, comprising: 2. The method for producing a polyimide composite according to claim 1, wherein the layered clay mineral is a smectite-based clay mineral using sodium ions as exchangeable alkali metal ions. 3. A polyimide composite produced by the method according to claim 1.