JP2003340919A - Method for manufacturing polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyimide film containing a swelling silicate. <P>SOLUTION: (1) A polyamide acid solution comprising polyamide acid practically composed of an aromatic diamine component having p-phenylenediamine as a main component and an aromatic tetracarbonate having pyromellitic acid as a main component, a swelling laminar silicate treated by an organic onium ion, and an organic polar solvent, is adjusted; (2) a gel-like film wherein a part of the polyamide acid is converted to polyimide or polyisoimide, is formed from the polyamide acid solution by using a dehydrating condensation agent and a cyclocatalyst; (3) the gel-like film prepared in the process (2) is drawn; and (4) an oriented polyimide film containing a laminar silicate is formed by submitting the obtained oriented film to heat treatment to provide the method for manufacturing the polyimide film. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyimide film containing a swelling silicate.

[0002]

2. Description of the Related Art Polyimide films have been widely developed due to their high heat resistance and mechanical properties. In particular, wholly aromatic polyimide is expected to exhibit particularly high heat resistance and mechanical properties due to its rigid structure, and is widely used in the field of electronic materials such as base films for lead-on-chip tape in flexible printed wiring boards and semiconductor devices. There is. However, as electronic devices have become smaller, thinner, lighter, and faster in recent years, the electronic components used for them have become smaller,
There is a strong demand for precision, and in order to realize it, thinning of polyimide film, high thermal dimensional stability and moisture absorption stability, and high gas barrier property are desired. As a method for improving mechanical properties such as elastic modulus and strength of a polyimide resin, JP-A-11-349709 proposes a polyimide film in which a layered silicate treated with an organic onium ion having an ethylene glycol chain is dispersed. Has been done. Further, as a method for improving the gas barrier property and the thermal dimensional stability of the polyimide resin, Japanese Patent Application Laid-Open No. 4 (1998) -54242
JP-A-33955 proposes a polyimide film in which a layered silicate treated with an alkylammonium ion is dispersed.

On the other hand, as a method for producing a polyimide film in which clay mineral is satisfactorily dispersed in a polyimide resin,
Japanese Unexamined Patent Publication No. 2000-302867 discloses a method of producing a clay mineral-dispersed aqueous solution and a polyamic acid,
Japanese Patent Publication No. 00-302897 describes a method of producing a mixture of a clay mineral and a polyamic acid with a dehydrating agent.

Further, JP-A-11-349709, JP-A-2000-302867 and JP-A-2000-
No. 302897 discloses that when a film is dried or imidized, it is easy to obtain a film having excellent mechanical properties by stretching, but no specific method is described and it is also practiced. Absent. On the other hand, Po
Lymer 42 (2001) 3399-3408, a polyimide consisting of 3,3 ′, 4,4′-biphenyltetracarboxylic acid anhydride and paraphenylenediamine is subjected to low temperature uniaxial stretching in a polyamic acid state and then heat treated. The uniaxially stretched layered silicate-containing polyimide film produced in 1. is described. However, the inclusion of the layered silicate reduces the mobility of the polymer chains, and the mechanical properties by stretching have not been improved as compared with the system containing no layered silicate. That is,
A polyimide-based film containing a layered silicate, which has improved mechanical properties as compared with a polyimide film containing no layered silicate by stretching, is not known.

[0005]

The object of the present invention is to obtain a polyimide film having high mechanical properties, thermal dimensional stability and gas barrier properties.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have made mechanical properties by highly orienting the layered silicate and polyimide contained in the polymer matrix. In particular, they have found a method for producing a polyimide film containing a swelling silicate having an improved tensile elastic modulus, and have reached the present invention.

That is, the present invention has the following configuration. 1. (1) Swelling layered layer treated with an organic onium ion, a polyamic acid consisting essentially of an aromatic diamine component containing p-phenylenediamine as a main component and an aromatic tetracarboxylic acid component containing pyromellitic acid as a main component A polyamic acid solution composed of a silicate and an organic polar solvent is prepared; (2) A gel form in which a part of the polyamic acid is converted to a polyimide or polyisoimide from the above polyamic acid solution using a dehydration condensation agent and a ring-closing catalyst. Forming a film; (3) stretching the gel film prepared in the above step (2); (4) subjecting the obtained stretched film to heat treatment to form a stretched polyimide-based film containing a layered silicate. A method for producing a polyimide-based film, comprising: 2. The polyimide is a p-phenylenediamine component 1
2. The method for producing a polyimide film as described in 1 above, which comprises a diamine component consisting of 00 mol% and an aromatic tetracarboxylic acid component consisting of 100 mol% of a pyromellitic acid component. 3. 3. The method for producing a polyimide film as described in any one of 1 to 2 above, wherein the organic onium ion is a quaternary ammonium ion. 4. Quaternary ammonium ion is shown by following formula 1, The manufacturing method of the polyimide film of said 1-3 characterized by the above-mentioned.

[0008]

[Chemical 2]

(R ₁ , R ₂ , R ₃ and R ₄ are each independently an alkyl group having 1 to 30 carbon atoms or ethylene oxide) 5. The method for producing a polyimide film as described in 1 to 4, wherein the swelling layered silicate is a smectite clay mineral of montmorillonite or a swelling mica.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polyimide film of the present invention and the method for producing the same are described in detail below.

The swellable layered silicate used in the present invention is
It is a layered silicate that has a cation exchange ability and that has the property of taking in water between layers and swelling. A smectite clay mineral of montmorillonite or swelling mica is preferred. Specific examples of the smectite-type clay include hectorite, saponite, stevensite, beidellite, montmorillonite, natural or chemically synthesized products thereof, or substitution products, derivatives, or mixtures thereof. Examples of the swelling mica include synthetic swelling mica having Li and Na ions between chemically synthesized layers, or a substitution product, derivative or mixture thereof.

Regarding the polyimide film of the present invention,
The swelling layered silicate is preferably contained in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the polyimide.
More preferably, the swellable layered silicate is 1 to 10 parts by weight. When the weight part of the swellable layered silicate is less than 0.1 part by weight with respect to 100 parts by weight of polyimide, the physical properties may not be improved. On the other hand, if the amount of the swellable layered silicate exceeds 100 parts by weight with respect to 100 parts by weight of the polyimide, the film may become brittle.

In the present invention, it is preferable to use the swellable layered silicate treated with an organic onium ion. The organic onium ion used is represented by the following formula (1)

[0014]

[Chemical 3]

A quaternary ammonium ion having the structure of (R ₁ , R ₂ , R ₃ and R ₄ are each independently an alkyl group having 1 to 30 carbon atoms or ethylene oxide) is preferred. Here, the alkyl group having 1 to 30 carbon atoms is preferably an alkyl group having 1 to 18 carbon atoms.

Specific examples of the quaternary ammonium ion used in the present invention include dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride,
Oleyltrimethylammonium chloride, didodecyldimethylammonium chloride, ditetradecyldimethylammonium chloride, dihexadecyldimethylammonium chloride, dioctadecyldimethylammonium chloride, dioleyldimethylammonium chloride, dodecyldiethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, Hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, oleyldimethylbenzyl chloride, hydroxypolyoxyethylenedodecyldimethylammonium chloride, hydroxypolyoxyethylenetetradecyldimethylammonium chloride, hydroxypolyoxye Len hexadecyl dimethyl ammonium chloride, hydroxypolyoxyethylene octadecyl dimethyl ammonium chloride, hydroxy polyoxyethylene oleyl dimethyl ammonium chloride, dihydroxy polyoxyethylene dodecyl methyl ammonium chloride, dihydroxy polyoxyethylene tetradecyl methyl ammonium chloride, dihydroxy polyoxyethylene hexadecyl Examples thereof include methylammonium chloride, dihydroxypolyoxyethylene octadecylmethylammonium chloride and dihydroxypolyoxyethylene oleylmethylammonium chloride.

The method of treating the swelling layered silicate with an organic onium ion is not particularly limited, but the swelling silicate 1
A method may be mentioned in which 1 part by weight and 1 to 10 parts by weight of organic onium ions are mixed in water and then dried. The amount of water is 1 to 100 times that of the swelling silicate. The temperature at the time of mixing is preferably 30 to 70 degrees, and the mixing time is preferably 0.5 to 2 hours. The drying conditions are 70-100
Drying under atmospheric pressure for 3 days at ℃ and vacuum drying for 2 days is preferable.

In the present invention, the polyimide can be obtained by subjecting a polyamic acid obtained by the condensation reaction of a tetracarboxylic acid anhydride and a diamine in a solution to a dehydration condensation reaction.

The aromatic diamine component specifically used in the present invention is p-phenylenediamine and an aromatic diamine different from p-phenylenediamine.

As the aromatic diamine component different from p-phenylenediamine, for example, m-phenylenediamine,
1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,6-diaminoanthracene, 2,7-diaminoanthracene,
1,8-diaminoanthracene, 2,4-diaminotoluene, 2,5-diamino (m-xylene), 2,5-diaminopyridine, 2,6-diaminopyridine, 3,5-
Diaminopyridine, 2,4-diaminotoluenebenzidine, 3,3′-diaminobiphenyl, 3,3′-dichlorobenzidine, 3,3′-dimethylbenzidine, 3,
3'-dimethoxybenzidine, 2,2'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,
3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylmethane, 4,
4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,
3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl thioether, 4,4'-diamino-3,3 ', 5,5' -Tetramethyldiphenyl ether, 4,4'-diamino-
3,3 ', 5,5'-tetraethyldiphenyl ether, 4,4'-diamino-3,3', 5,5'-tetramethyldiphenylmethane, 1,3-bis (3-aminophenoxy) benzene, 1,3 -Bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy)
Benzene, 2,6-bis (3-aminophenoxy) pyridine, 1,4-bis (3-aminophenylsulfonyl)
Benzene, 1,4-bis (4-aminophenylsulfonyl) benzene, 1,4-bis (3-aminophenylthioether) benzene, 1,4-bis (4-aminophenylthioether) benzene, 4,4′-bis (3-Aminophenoxy) diphenyl sulfone, 4,4′-bis (4-aminophenoxy) diphenyl sulfone, bis (4-aminophenyl) amine bis (4-aminophenyl) -N-methylamine bis (4-aminophenyl) −
N-phenylamine bis (4-aminophenyl) phosphine oxide, 1,1-bis (3-aminophenyl) ethane, 1,1-bis (4-aminophenyl) ethane,
2,2-bis (3-aminophenyl) propane, 2,2
-Bis (4-aminophenyl) propane, 2,2-bis (4-amino-3,5-dimethylphenyl) propane,
4,4'-bis (4-aminophenoxy) biphenyl,
Bis [4- (3-aminophenoxy) phenyl] sulfone, Bis [4- (4-aminophenoxy) phenyl] sulfone, Bis [4- (4-aminophenoxy) phenyl] ether, Bis [4- (4-amino) Phenoxy) phenyl] methane, bis [3-methyl-4- (4-aminophenoxy) phenyl] methane, bis [3-chloro-4
-(4-aminophenoxy) phenyl] methane, bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1 , 1-bis [3-methyl-4- (4-aminophenoxy) phenyl] ethane,
1,1-bis [3-chloro-4- (4-aminophenoxy) phenyl] ethane, 1,1-bis [3,5-dimethyl-4- (4-aminophenoxy) phenyl] ethane,
2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4-
Aminophenoxy) phenyl] propane, 2,2-bis [3-chloro-4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3,5-dimethyl-4-]
(4-Aminophenoxy) phenyl] propane, 2,2
-Bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [3-methyl-4- (4-aminophenoxy) phenyl] butane, 2,2-bis [3,5-dimethyl-4] -(4-Aminophenoxy) phenyl] butane, 2,2-bis [3,5-dibromo-4- (4-aminophenoxy) phenyl] butane, 1,1,1,3
3,3-hexafluoro-2,2-bis (4-aminophenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis [3-methyl-4- (4- Aminophenoxy) phenyl] propane and the like, and aromatic nucleus substitution products thereof with a halogen atom or an alkyl group thereof.

The diamine component consists of p-phenylenediamine alone or in combination with p-phenylenediamine and an aromatic diamine different from that as described above. In the latter combination, p-phenylenediamine is present in a proportion of more than 80 mol%, preferably of more than 90 mol%, i.e. of less than 20 mol%, preferably of less than 1 mol, based on the total diamine component.
It comprises less than 0 mol%.

The tetracarboxylic acid component constituting the polyamic acid is pyromellitic acid and aromatic tetracarboxylic acid different from it.

Examples of the aromatic tetracarboxylic acid component different from pyromellitic acid include 1,2,3,4-benzenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 2,3,4,5-thiophene tetracarboxylic acid dianhydride, 2,2 ', 3,3'-benzophenone tetracarboxylic acid dianhydride, 2,3',
3,4′-benzophenone tetracarboxylic acid dianhydride,
3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Dianhydride, 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-p
-Terphenyltetracarboxylic dianhydride, 2,2 ',
3,3'-p-terphenyltetracarboxylic dianhydride, 2,3,3 ', 4'-p-terphenyltetracarboxylic dianhydride, 1,2,4,5-naphthalenetetracarboxylic dianhydride Anhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,5,6-anthracenetetracarboxylic dianhydride, 1 , 2, 6, 7-
Phenanthrene tetracarboxylic dianhydride, 1,2,
7,8-phenanthrene tetracarboxylic acid dianhydride,
1,2,9,10-phenanthrenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,5
8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride,
2,3,6,7-tetrachloronaphthalene-1,4
5,8-Tetracarboxylic acid dianhydride, 1,4,5,8-
Tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-Dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4- Dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride,
1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxy) Phenyl) propane dianhydride, 2,6-bis (3,4-dicarboxyphenoxy) pyridine dianhydride, 1,1,1,3,3,3-hexafluoro-2,2
Examples thereof include bis (3,4-dicarboxyphenyl) propane dianhydride and bis (3,4-dicarboxyphenyl) dimethylsilane dianhydride.

The tetracarboxylic acid component consists of pyromellitic acid alone or in combination with pyromellitic acid and an aromatic tetracarboxylic acid different from that as described above. In the case of the latter combination, pyromellitic acid is a proportion of more than 80 mol% based on the total tetracarboxylic acid component,
It is preferably greater than 90 mol%, ie less than 20 mol%, preferably less than 10 mol%, of aromatic tetracarboxylic acids different therefrom.

A diamine component consisting of 100 mol% of p-phenylenediamine component and 100 parts of pyromellitic acid component.
When the polyimide is composed of an aromatic tetracarboxylic acid component composed of mol%, more preferable high mechanical properties are exhibited.

The polyimide film produced according to the present invention has a high tensile elastic modulus which has never been seen and an excellent balance of the tensile elastic modulus in the plane of the film, which is excellent in practical use.

The solvent for polymerizing the polyamic acid may be any solvent which dissolves the polyamic acid and does not react with the condensing agent. Specific examples include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide,
Examples thereof include 1,3-dimethylimidazolidinone, tetramethylurea, 1,3-dipropylimidazolidinone, N-methylcaprolactam and dimethyl sulfoxide. Polyamic acid causes hydrolysis due to water,
The solvent is preferably dehydrated.

When the polyamic acid is produced, the diamine component and the acid anhydride component are preferably contained in a molar ratio of diamine component to acid anhydride component of 0.90 to 1.1.
It is preferably 0, more preferably 0.95 to 1.05.

The end of this polyamic acid is preferably sealed. In the case of using a terminal blocking agent, examples of the terminal blocking agent include phthalic anhydride and a substituted product thereof, hexahydrophthalic anhydride and a substituted product thereof, succinic anhydride and a substituted product thereof, and an amine component. Examples include aniline and its substitution products.

The method for producing a polyimide film containing a swelling silicate will be described below.

First, in the step (1), a polyamic acid or an organic onium ion which is substantially composed of an aromatic diamine component containing p-phenylenediamine as a main component and an aromatic tetracarboxylic acid component containing pyromellitic acid as a main component. A polyamic acid solution comprising a swellable layered silicate treated with and a polar organic solvent is prepared, but the polyamic acid concentration is preferably 1 to 15% by weight, more preferably 3 to 10% by weight.
A solution of polyamic acid is prepared.

The amounts of the polyamic acid and the swellable layered silicate are in the range of 0.1 to 20 parts by weight of the swellable layered silicate with respect to 100 parts by weight of the polyimide in the polyimide film obtained as described above. It is preferable that the swellable layered silicate is contained in the range of 1 to 10 parts by weight.

As the organic polar solvent, the organic polar solvent used for the polymerization of polyamic acid is preferably used.

The method for mixing the polyamic acid solution and the layered silicate is not particularly limited, and the swellable layered silicate is added as a solid to the polyamic acid solution or added in a state of being dispersed in an organic solvent in advance. Method is used,
It is necessary to stir and knead the mixed solution until it becomes a uniform state.

Subsequently, in the step (2), a gel-like film in which a part of the polyamic acid is converted into polyimide or polyisoimide by using the dehydrated condensing agent and the ring-closing catalyst, is obtained the mixed solution of the polyamic acid and the layered silicate. To get

In order to cast the mixed solution of the polyamic acid and the layered silicate on the support, any generally known dry method and dry-wet molding method may be used. Examples of the film forming method include a die extrusion method, casting using an applicator, and a method using a coater. When casting a mixed solution of polyamic acid and layered silicate, a metallic belt as a support,
A casting drum or the like can be used. It can also be cast on an organic polymer film such as polyester or polypropylene. These steps are preferably performed in a low humidity atmosphere in order to suppress hydrolysis of the polymer.

In the present invention, the dehydration condensing agent includes acetic anhydride, propionic anhydride, valeric anhydride, benzoic anhydride,
Acid anhydrides such as trifluoroacetic acid dianhydride may be mentioned as condensing agents.

In the present invention, the ring-closing catalyst may be a tertiary aliphatic amine such as triethylamine, tributylamine or diisopropylethylamine; an aromatic such as N, N-dimethylaniline or 1,8-bis (N, N-dimethylamino) naphthalene. Amines, pyridine and its derivatives, picoline and its derivatives, lutidine, quinoline,
Heterocyclic compounds such as isoquinoline can be used. In addition, organic amine compounds such as triethylenediamine and N, N-dimethylaminopyridine are preferable because they enable efficient ring closure reaction of polyamic acid with a small amount.

As a method for obtaining a gel-like film in which a part of polyamic acid is converted to polyimide or polyisoimide, a mixed solution of polyamic acid and layered silicate contains a dehydration condensing agent having a stoichiometric amount or more and an imidization catalyst. There is a method of introducing a cast film into a solution (reaction coagulating liquid) to obtain a gel film. At this time, the reaction coagulation liquid may use an organic solvent as a diluent. As the diluent, a general organic solvent that dissolves the dehydration condensation agent and the imidization catalyst, does not react with the dehydration condensation agent and the imidization catalyst, and does not dissolve the polyimide precursor may be used. The solvent is not particularly limited, but it is preferable to use the solvent used as the solvent when polymerizing the polyamic acid.

On the other hand, a dehydration condensing agent having a stoichiometric amount or more and an imidization catalyst were added at a low temperature to a mixed solution of a polyamic acid and a layered silicate to prepare a molding dope, and then film casting was performed as described above. It is also possible to produce a gel film by drying.

When the imide group fraction and the isoimide group fraction of the gel film are 20% to 100%, a high stretch ratio can be obtained, which is preferable. Furthermore, it is more preferable that no amic acid residue is present. With the remaining amide acid residue,
It causes hydrolysis and causes deterioration of physical properties.

It is preferable that the gel film has a swelling degree of 300 to 5000% because a high stretch ratio can be obtained.
When it is 300% or less, the stretchability is insufficient, and when it is 5000% or more, the strength of the gel decreases and handling becomes difficult.

In step (3), mechanical strength and thermal dimensional stability can be improved by separating the obtained unstretched gel film from the support and subjecting it to a stretching treatment. The stretching treatment is preferably biaxial stretching from the viewpoint of excellent in-plane balance in the film. Stretching may be performed after the unstretched film is separated from the support and then washed, or may be performed without washing. For the washing, for example, a solvent similar to the solvent used in the step (1) is used. As the stretching method, any generally known method may be used. In biaxial stretching, either simultaneous or sequential stretching may be used. The stretching may be carried out in a solvent, air, an inert atmosphere, or heated at a low temperature.
The temperature at the time of stretching is not particularly limited,
It only needs to be such that the solvent does not evaporate and the stretchability does not decrease.

In step (4), the gel-like film is heat-treated under a fixed length or under tension to form a polyimide film containing a biaxially oriented layered silicate. As the heat treatment temperature, it is preferable to carry out the heat treatment at a temperature of 300 to 550 ° C. because it can be realized by suppressing the orientation relaxation of the imidization ratio exceeding 95%. Examples of the heat treatment method include, but are not limited to, hot air heating, vacuum heating, infrared heating, microwave heating, and heating by contact using a hot plate or a hot roll. At this time, it is preferable to promote the imidization by raising the temperature stepwise.

In the stretched polyimide film containing the layered silicate thus obtained, the molecular chains are strongly oriented in the plane of the film, and at the same time, the layered silicate present in the polymer matrix is strongly oriented in the plane. In particular, by stretching in the biaxial direction, a polyimide film having a high tensile elastic modulus with excellent in-plane balance is obtained, and the Young's modulus value measured in the in-plane two orthogonal directions exceeds 14 GPa, and depending on the stretching orientation. A film having improved strength can be obtained by forming a special fine structure. Such a high tensile elastic modulus film can be suitably used for electronic applications, such as a support for an electric wiring board laminated with a copper thin film, even if it is a thin film having a thickness of 10 μm or less due to its high rigidity. It can also be used as a support for flexible circuit boards, TAB (tape automated bonding) tapes, and LOC (lead-on-chip) tapes. It can also be used as a base film of a magnetic recording tape.

[0046]

EFFECTS OF THE INVENTION According to the present invention, it is possible to preferably obtain a polyimide film composed of a swellable layered silicate treated with a polyimide and an organic onium ion, and the polyimide film has a highly oriented layered silicate and polyimide. By doing so, it has high tensile elasticity and is excellent as a film for electronic materials.

[0047]

EXAMPLES The method of the present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited by these examples.

The montmorillonite used in this example was from Kunimine Industry Co., Ltd., and the dihydroxypolyoxyethylene oleylmethylammonium chloride was from Takemoto Yushi Co., Ltd.

[Measurement of logarithmic viscosity of polyamic acid] The logarithmic viscosity of polyamic acid was measured at 30 ° C. in NMP (N-methyl-2-pyrrolidone) at a polymer concentration of 0.5 g / 100 ml.

[Measurement of ash content] The content of the inorganic substance derived from the layered silicate is based on JISK7052, and the combustion is heated at a temperature of 950 ° C. for 3 hours, and the weight of the inorganic substance of the polyimide film containing the layered silicate is measured. Was measured.

[Measurement of Elastic Modulus / Elongation] A 50 mm × 10 mm sample was used to measure the elastic modulus and elongation at a pulling speed of 2 mm / min.
It is measured by -1T.

[Example 1] (a) Preparation of swellable layered silicate dispersion 100 g of montmorillonite, 100 g of dihydroxypolyoxyethylene oleylmethyl ammonium chloride
10 L of water was added to the mixture, the mixture was stirred at room temperature for 2 hours, and a crude product was obtained by filtration. Further, after washing with 10 L of water three times, hot air drying was performed at 100 ° C. for 3 days and vacuum drying was performed for 2 days to obtain quaternary ammonium ion-treated montmorillonite. The obtained quaternary ammonium ion-treated montmorillonite was dispersed in N-methyl-2-pyrrolidone in an amount of 5% by weight to obtain a uniform opaque layered silicate dispersion.

(B) Preparation of Polyamic Acid Solution A reaction vessel equipped with a thermometer, a stirrer, and a raw material inlet was dehydrated with molecular sieves under a nitrogen atmosphere to produce N-.
Methyl-2-pyrrolidone (800 ml) was added, and paraphenylenediamine (11.9 g) was further added to completely dissolve it, followed by cooling to 0 ° C. in an ice bath. To this cooled diamine solution, 24.1 g of pyromellitic dianhydride was added and further reacted. After completion of the reaction, the mixture was filtered under a nitrogen atmosphere and defoamed to obtain a polyamic acid solution. The logarithmic viscosity of this solution is 14.1
And the final polymer concentration was 4% by weight.

(C) Production of Film The layered silicate dispersion prepared by the above method and the polyamic acid solution were mixed at room temperature to prepare a mixed solution containing the polyamic acid and the layered silicate. The resulting mixed solution of polyamic acid and layered silicate was cast on a corona-treated polypropylene film using a 0.3 mm doctor blade.
350 ml of acetic anhydride, 150 ml of pyridine, N-
Methyl-2-pyrrolidone was introduced into 500 ml of a reaction coagulation solution, reacted and coagulated for 10 minutes, peeled from the support, and further reacted for 10 minutes for 20 minutes to obtain a gel film. The obtained gel film was stretched 1.7 times in the machine and transverse directions using a simultaneous biaxial stretching machine, fixed on a metal frame, washed with toluene, and then dried at 200 ° C. for 20 minutes. Then, the temperature was gradually increased to 450 ° C. and heat treatment was performed to obtain a biaxially stretched polyimide-based film having a transparent layered silicate. From the ash content measurement result, the content of the inorganic component was 1.2% by weight. The thickness of the obtained film is 1
5 μm, tensile elastic modulus is 1 in the orthogonal stretching direction
The values were 5.5 GPa and 15.5 GPa, the tensile strengths were 0.41 GPa and 0.37 GPa, and the elongations were 8.0% and 6.4%, respectively.

Comparative Example 1 A polyimide film containing no swelling silicate was obtained in the same manner as in Example 1 except that the swelling silicate was not contained. The thickness of the obtained film is 1
5 μm, tensile elastic modulus is 1 in the orthogonal stretching direction
2.5 GPa and 13.6 GPa, tensile strengths were 0.35 GPa and 0.39 GPa, and elongations were 12.5% and 13.7%, respectively.

[Comparative Example 2] An unstretched polyimide film containing a swelling silicate was obtained in the same manner as in Example 1 except that stretching was not performed. The thickness of the obtained film is 15μ
m, the tensile elastic modulus is 11.5 in the orthogonal stretching direction.
GPa and 12.1 GPa, tensile strengths were 0.18 GPa and 0.18 GPa, and elongations were 1.8% and 1.9%, respectively.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 105: 16 B29K 105: 16 B29L 7:00 B29L 7:00 F term (reference) 4F071 AA60 AB26 AE17 AF08 BA06 BA07 BB02 BB07 BB12 BC01 4F210 AA40 AB11 AB16 AB27 AG01 AH36 QC07 QD01 QG01 QW05 QW17 4J002 CM041 DJ006 FB086 FD016

Claims (5)

[Claims] (1) Treatment with a polyamic acid substantially composed of an aromatic diamine component containing p-phenylenediamine as a main component and an aromatic tetracarboxylic acid component containing pyromellitic acid as a main component, and an organic onium ion. A polyamic acid solution containing the swellable layered silicate and an organic polar solvent prepared; (2) From the polyamic acid solution, a part of the polyamic acid is converted into a polyimide or polyisoimide by using a dehydration condensation agent and a ring-closing catalyst. Forming a converted gel-like film; (3) stretching the gel-like film prepared in the above step (2); (4) subjecting the obtained stretched film to heat treatment to obtain a stretched polyimide containing layered silicate A method for producing a polyimide-based film, comprising forming a film-based film. 2. The polyimide film according to claim 1, wherein the polyimide comprises a diamine component consisting of 100 mol% of a p-phenylenediamine component and an aromatic tetracarboxylic acid component consisting of 100 mol% of a pyromellitic acid component. Manufacturing method. 3. The method for producing a polyimide film according to claim 1, wherein the organic onium ion is a quaternary ammonium ion. 4. The method for producing a polyimide film according to claim 1, wherein the quaternary ammonium ion is represented by the following formula 1. [Chemical 1] (R ₁ , R ₂ , R ₃ and R ₄ each independently have 1 carbon atom
~ 30 alkyl groups or ethylene oxide) 5. The method for producing a polyimide film according to claim 1, wherein the swelling layered silicate is a smectite clay mineral of montmorillonite or a swelling mica.