JP3022625B2 - Polyamic acid copolymer, polyimide copolymer comprising the same, polyimide film, and methods for producing them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamic acid copolymer which gives a polyimide film having excellent heat resistance, high elasticity, low thermal expansion and low moisture absorption, a polyimide copolymer comprising the same, a polyimide film and a polyimide film thereof. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Hitherto, a polyimide resin has excellent electrical insulation as well as excellent heat resistance, and is widely used as an industrial material including electric equipment. Polyimide resins have various excellent properties compared to other polymers, but with the advancement of technology, the required properties of polyimide resins also become advanced, and various properties must be combined according to the application. Is desired.

[0003] When it is considered to be used for electric equipment, if the hygroscopicity is high, the electrical insulation is reduced, and the risk of contamination with ionic impurities is increased, and the reliability as a material is undesirably reduced. Therefore, low moisture absorption is desired. Further, from the viewpoint of strength as a material, it is desirable that the material has high elasticity. Since it is preferable that the dimensional change is small with respect to the temperature change, low thermal expansion is required.

For example, if only a rigid straight chain such as pyromellitic anhydride and paraphenylenediamine is used, a polyimide having high elasticity and low thermal expansion can be synthesized. However, this structure is very brittle and lacks flexibility,
Only films with high hygroscopicity can be obtained. Also,
Polyimide is generally a resin having relatively high water absorption due to large polarization of a carbonyl group and a nitrogen atom in an imide ring. Thus, there is a need for a polyimide that sufficiently satisfies the physical properties of high elasticity, low moisture absorption, and appropriate flexibility.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a polyamic acid copolymer which provides a polyimide film having excellent properties such as excellent heat resistance, high elasticity, low coefficient of thermal expansion, and low moisture absorption, and a polyimide copolymer comprising the same. It is an object of the present invention to provide a united film, a polyimide film, and a production method thereof.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have made intensive studies on the molecular structure of polyimide, and as a result, it has been found that polyimide having a specific structural unit has high elasticity, low thermal expansion, and low moisture absorption. The present inventors have found that the present invention has good properties and moderate flexibility, and completed the present invention. That is, the first of the present invention
Is the following structural formula

[0007]

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(However, R ₂ , R ₄ , R ₆ , and R ₈ are linear diamine residues, R ₁₀ is a flexible diamine residue, R ₃ ,
R ₇ represents a pyromellitic dianhydride residue, and R ₁ ,
R ₅ and R ₉ are the following groups

[0009]

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These are arbitrarily selected from the following. A) a polyamic acid copolymer having a structural unit represented by

A second aspect of the present invention for producing the above polyamic acid copolymer is to add 2 equivalents of pyromellitic dianhydride to 4 equivalents of at least one linear diamine,
The following structural formula

[0012]

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A method for producing a polyamic acid copolymer, comprising adding 3 equivalents of at least one kind of tetracarboxylic dianhydride selected from the group and then adding 1 equivalent of at least one kind of flexible diamine,

A third aspect of the present invention for producing the above polyamic acid copolymer is that one equivalent of at least one kind of flexible diamine has the following structural formula

[0015]

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After adding 2 equivalents of at least one kind of tetracarboxylic dianhydride selected from the above, adding 2 equivalents of at least one linear diamine, then adding 2 equivalents of pyromellitic dianhydride, A method for producing a polyamic acid copolymer, comprising adding 2 equivalents of one kind of linear diamine and adding 1 equivalent of at least one kind of tetracarboxylic dianhydride selected from the above structural formulas,

A fourth aspect of the present invention for producing the above polyamic acid copolymer is that at least one equivalent of a linear diamine is added with the following structural formula

[0018]

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One equivalent of at least one tetracarboxylic dianhydride selected from the above, 2 equivalents of pyromellitic dianhydride, and at least one linear diamine 2
At least one of the above structural formulas
A method for producing a polyamic acid copolymer, comprising adding 2 equivalents of a tetracarboxylic dianhydride and then adding 1 equivalent of at least one flexible diamine,

A fifth aspect of the present invention is a polyimide copolymer obtained by dehydrating and ring-closing the polyamic acid copolymer of the first aspect, and a sixth aspect of the present invention is a polyamic acid copolymer obtained by the second aspect. The method for producing a polyimide copolymer, which comprises dehydrating and ring-closing the union, is described in the seventh aspect of the present invention.
The method for producing a polyimide copolymer, which comprises dehydrating and cyclizing the polyamic acid copolymer obtained in the invention, the eighth aspect of the present invention is to dehydrate and ring-close the polyamic acid copolymer obtained in the fourth invention. A method for producing a polyimide copolymer, characterized by:

A ninth aspect of the present invention is to provide a polyimide film comprising the polyamic acid copolymer of the first aspect, and a tenth aspect of the present invention is to provide the polyamic acid copolymer obtained by the second aspect on a support. According to a eleventh aspect of the present invention, there is provided a method for producing a polyimide film, comprising casting and dehydrating and ring-closing a polyimide film, wherein the polyamic acid copolymer obtained in the third aspect is cast on a support and dehydrated. The method for producing a polyimide film, which is characterized in that
The present invention relates to a method for producing a polyimide film, comprising casting and coating the polyamic acid copolymer obtained in the fourth invention on a support, followed by dehydration and ring closure, respectively.

Hereinafter, the present invention will be described in detail. The linear diamine used in the present invention refers to a diamine compound having a structure that does not include a bending group such as an ether bond and has a structure in which a main chain direction of a diamine matches a straight line connecting two nitrogen atoms. For example,

[0023]

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(Where X is F, Cl, Br, CH
₃ -, CH ₃ O- or CF ₃ - shows the. And the like.

A flexible diamine has a structure in which a main chain contains a bending group such as an ether bond or a carbonyl group, or a main chain direction of a diamine does not coincide with a straight line connecting two nitrogen atoms. Diamine compound. For example,

[0026]

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[0027]

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(Where X is H, F, Cl, Br, CH
_3- , CH ₃ O- and CF ₃ -are shown. And the like. In addition, a flexible diamine residue (R
_{If a} long-chain diamine is used in ₁₀ ), lower hygroscopicity can be realized.

In the polyamic acid copolymer and the polyimide film of the present invention, it is important that the respective structural units are regularly arranged in the same order as the above structural units. Use a simple synthesis method. The polyimide copolymer is obtained from a polyamic acid copolymer solution that is a precursor of the polyimide copolymer, and the polyamic acid copolymer solution is obtained by polymerizing an acid anhydride and a diamine component in an organic polar solvent using substantially equimolar amounts. Is obtained.

The organic polar solvent used in the reaction for producing the polyamic acid copolymer includes, for example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, N, N-diethylformamide N, N-
Acetamide solvents such as dimethylacetamide and N, N-diethylacetamide; pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone; phenol, o-, m- or p-cresol;
Xylenol, halogenated phenols, phenolic solvents such as catechol, or hexamethylphosphoramide, γ-butyrolactone, and the like can be mentioned, and it is preferable to use these alone or as a mixture of two or more. Partial use of aromatic hydrocarbons such as toluene is also possible.

A specific example of a method for synthesizing a polyamic acid copolymer solution will be described. Synthetic Method 1 In a vessel, 4 equivalents of one or more of an organic polar solvent and a linear diamine are taken and cooled and stirred. Add 2 equivalents of pyromellitic dianhydride to the above mixture, preferably add 2 equivalents.
Cool and stir for 0 minutes or more. One or more tetracarboxylic dianhydrides selected from the following three are added in an amount of 3 equivalents, and the mixture is preferably cooled and stirred for at least 20 minutes.

[0032]

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One or two or more kinds of flexible diamines are gradually added to one equivalent with cooling and stirring to obtain the polyamic acid copolymer solution.

Synthesis Method 2 One or more equivalents of one or more of an organic polar solvent and a flexible diamine are placed in a vessel, and cooled and stirred. One or two of tetracarboxylic dianhydrides selected from the above three types
Two or more equivalents of the seed or more are added, and the mixture is cooled and stirred for preferably 20 minutes or more. One or more linear diamines are added in an amount of 2 equivalents, and the mixture is cooled and stirred for preferably 20 minutes or more. Add 2 equivalents of pyromellitic dianhydride to the above mixture. One or more linear diamines are added in an amount of 2 equivalents, and the mixture is cooled and stirred for preferably 20 minutes or more. One or two or more of the tetracarboxylic dianhydrides selected from the above three types are
By gradually adding the equivalent amount, the polyamic acid copolymer solution can be obtained.

Synthesis Method 3 Two or more equivalents of one or more of an organic polar solvent and a linear diamine are placed in a vessel and cooled and stirred. One or two of tetracarboxylic dianhydrides selected from the above three types
One equivalent of the seed or more is added and the mixture is cooled and stirred preferably for 20 minutes or more. Two equivalents of pyromellitic dianhydride are added to the above mixture, and the mixture is cooled and stirred preferably for 20 minutes or more. One or more linear diamines are added in an amount of 2 equivalents, and the mixture is cooled and stirred for preferably 20 minutes or more. One or more tetracarboxylic dianhydrides selected from the above three are added in an amount of 2 equivalents, and the mixture is preferably cooled and stirred for at least 20 minutes. The polyamic acid copolymer can be obtained while slowly cooling and stirring one or more kinds of flexible diamines by one equivalent. The polyamic acid copolymer obtained as described above is preferably dissolved in the organic polar solvent in an amount of 5 to 40% by weight, more preferably 10 to 30% by weight, from the viewpoint of handling. .

From this aromatic polyamic acid copolymer solution, the following formula

[0037]

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In order to obtain the polyimide copolymer and the polyimide film of the present invention having the structural unit represented by the formula (1), any of a thermal method of thermally dehydrating and a chemical method using a dehydrating agent may be used. However, according to the chemical method, the resulting polyimide film has excellent mechanical properties such as elongation and tensile strength, which is preferable. Hereinafter, an example of a method for producing a polyimide film will be described.

A polyamic acid polymer or a solution obtained by adding a dehydrating agent having a stoichiometric amount or more and a catalytic amount of a tertiary amine to a solution thereof is cast or coated on a support such as a drum or an endless belt to form a film. The film is dried at a temperature of 150 ° C. or lower for about 5 to 90 minutes to obtain a self-supporting polyamic acid film. Next, this is peeled off from the support and the end is fixed. Thereafter, the polyimide film is gradually heated to about 100 to 500 ° C. to be imidized, and after cooling, is removed from a drum or an endless belt to obtain a polyimide film of the present invention. Examples of the dehydrating agent mentioned here include aliphatic acid anhydrides such as acetic anhydride, aromatic acid anhydrides, and the like. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline and isoquinoline.

[0040]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, ODA is 4,4'-diaminodiphenyl ether, BAPB is 4,4'-bis (aminophenoxyphenyl) biphenyl, BAPP is 4,4'-bis (aminophenoxyphenyl) propane, and p-PDA is paraphenylene. Diamine, TPE-Q is 1,4-bis (4-aminophenoxy) benzene, PMDA is pyromellitic anhydride, BTDA is benzophenonetetracarboxylic dianhydride, BPDA is biphenyltetracarboxylic dianhydride, DMF is dimethylformamide Represents

Example 1 DMF and p-PDA were placed in a 2-liter separable flask.
Was added at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 2 equivalents of PMDA were added and the mixture was cooled and stirred for 40 minutes. Then, 3 equivalents of BTDA were added at once, and the mixture was cooled and stirred for 40 minutes. One equivalent of ODA was dissolved in DMF, added gradually, and then cooled and stirred for 1 hour to obtain a DMF solution of polyamic acid. The amount of DMF used is such that the monomer charge concentration of the diamino compound and the aromatic tetracarboxylic acid compound is 18%.
% By weight. The polyamic acid solution was applied on a glass plate by casting and dried at about 100 ° C. for about 30 minutes. Then, the polyamic acid coating film was peeled off from the glass plate, and the coating film was fixed on a support frame. About 200 minutes
The resultant was heated at about 60 ° C. for about 60 minutes and at about 300 ° C. for about 60 minutes. Table 1 shows the physical properties of the obtained polyimide film.

Example 2 DMF and p-PDA were placed in a 2-liter separable flask.
Was added at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 2 equivalents of PMDA were added and the mixture was cooled and stirred for 40 minutes. Then, 3 equivalents of BTDA were added at once, and the mixture was cooled and stirred for 40 minutes. Dissolve 1 equivalent of TPE-Q in DMF and slowly add
Thereafter, the mixture was cooled and stirred for 1 hour to obtain a polyamic acid DMF solution. It was fired in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the physical properties of the obtained polyimide film.

Example 3 DMF and p-PDA were placed in a 2-liter separable flask.
Was added at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 2 equivalents of PMDA were added and the mixture was cooled and stirred for 40 minutes. Then, 3 equivalents of BTDA were added at once, and the mixture was cooled and stirred for 40 minutes. One equivalent of BAPB was dissolved in DMF, added gradually, and then cooled and stirred for 1 hour to obtain a polyamic acid DMF solution. It was fired in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the physical properties of the obtained polyimide film.

Example 4 DMF and p-PDA were placed in a 2-liter separable flask.
Was added at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 2 equivalents of PMDA were added and the mixture was cooled and stirred for 40 minutes. Then, 3 equivalents of BTDA were added at once, and the mixture was cooled and stirred for 40 minutes. One equivalent of BAPP was dissolved in DMF, added gradually, and then cooled and stirred for 1 hour to obtain a DMF solution of polyamic acid. It was fired in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the physical properties of the obtained polyimide film.

Example 5 DMF and p-PDA were placed in a 2-liter separable flask.
Was added at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 2 equivalents of PMDA were added and the mixture was cooled and stirred for 40 minutes. Then, 3 equivalents of BPDA were added at once, and the mixture was cooled and stirred for 40 minutes. One equivalent of BAPB was dissolved in DMF, added gradually, and then cooled and stirred for 1 hour to obtain a polyamic acid DMF solution. It was fired in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the physical properties of the obtained polyimide film.

Comparative Example 1 In the same manner as in Example 1, a polyimide film was obtained using PMDA and ODA in equimolar amounts. Table 1 shows the physical properties of the obtained polyimide film.

Comparative Example 2 DMF and p-PDA were placed in a 2-liter separable flask.
4 equivalents and 1 equivalent of ODA were mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 3 equivalents of BTDA and 2 equivalents of PMDA were gradually added, followed by cooling and stirring for 1 hour to obtain a DMF solution of polyamic acid. It was fired in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the physical properties of the obtained polyimide film.

[0048]

[Table 1] 1) According to ASTM D-570 2) 100 measured by Rigaku TMA8140
Thermal expansion coefficient up to 200 ° C

[0049]

As described above, according to the present invention, a polyimide film having excellent heat resistance, high elasticity, low thermal expansion and low moisture absorption can be obtained.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 73/10

Claims (12)

(57) [Claims] [Claim 1] The following formula: (However, R ₂ , R ₄ , R ₆ , R ₈ are linear diamine residues, R ₁₀ is a flexible diamine residue, R ₃ , R ₇ are pyromellitic dianhydride residues, and R ₁ , R ₅ and R ₉ are the following groups: Arbitrarily selected from A) a polyamic acid copolymer having a structural unit represented by the formula: 2. At least one equivalent of a linear diamine and 2 equivalents of pyromellitic dianhydride are added to 4 equivalents of a linear diamine. 3. The method for producing a polyamic acid copolymer according to claim 1, wherein 3 equivalents of at least one kind of tetracarboxylic dianhydride selected from the following are added, and then 1 equivalent of at least one kind of flexible diamine is added. . 3. An equivalent of at least one flexible diamine is represented by the following structural formula: After adding 2 equivalents of at least one kind of tetracarboxylic dianhydride selected from the following, adding 2 equivalents of at least one linear diamine, then adding 2 equivalents of pyromellitic dianhydride, and adding at least one kind of The method for producing a polyamic acid copolymer according to claim 1, wherein 2 equivalents of a linear diamine is added, and 1 equivalent of at least one kind of tetracarboxylic dianhydride selected from the above structural formulas is added. 4. At least one linear diamine in 2 equivalents has the following structural formula: Adding 1 equivalent of at least one tetracarboxylic dianhydride selected from among them, adding 2 equivalents of pyromellitic dianhydride, adding 2 equivalents of at least one linear diamine,
2. The polyamic acid copolymer according to claim 1, wherein after adding 2 equivalents of at least one kind of tetracarboxylic dianhydride selected from the above structural formulas, 1 equivalent of at least one kind of flexible diamine is added. Manufacturing method of coalescence. 5. A polyimide copolymer obtained by subjecting the polyamic acid copolymer according to claim 1 to dehydration ring closure. 6. A method for producing a polyimide copolymer, wherein the polyamic acid copolymer obtained in the production method according to claim 2 is subjected to dehydration ring closure. 7. A method for producing a polyimide copolymer, comprising subjecting the polyamic acid copolymer obtained in the production method according to claim 3 to dehydration ring closure. 8. A method for producing a polyimide copolymer, comprising subjecting the polyamic acid copolymer obtained in the production method according to claim 4 to dehydration and ring closure. 9. A polyimide film comprising the polyamic acid copolymer according to claim 1. 10. A method for producing a polyimide film, comprising casting the polyamic acid copolymer obtained in the production method according to claim 2 on a support and dehydrating and ring-closing the polyimide film. 11. A method for producing a polyimide film, comprising casting the polyamic acid copolymer obtained in the production method according to claim 3 onto a support and dehydrating and ring-closing the polyimide film. 12. A method for producing a polyimide film, comprising casting and coating the polyamic acid copolymer obtained in the production method according to claim 4 on a support, followed by dehydration ring closure.