JPH11236448A - Polyimide film and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a polyimide film having excellent heat resistance, excellent mechanical properties such as high elastic modulus, and low water absorption, and a method for producing the same. SOLUTION: General formula (1) (Wherein, R1 is: (R _Z is at least one selected from H, CH ₃ , Cl, and Br, Z is an integer of 0 to 4), and R 2 is at least one selected from the group consisting of ] (R _m and R _n are at least one selected from H, CH ₃ , Cl, and Br, and Z is an integer of 0 to 4). The present invention provides a polyimide film containing a repeating unit represented by the formula (1), and a method for producing the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel polyimide film having excellent mechanical properties such as elasticity, low water absorption and heat resistance, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a polyimide film, pyromellitic dianhydride and 4,4'-dianodiphenyl ether
Polyimides made of tellurium and polyimides made of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine are widely used. In particular, flexible printed wiring is used due to its excellent heat resistance and electrical insulation properties. It is widely used as an electronic material such as a board (hereinafter, FPC) or a base film for a lead-on-chip (LOC) tape in a semiconductor device. Furthermore, polyimide films have excellent radiation resistance and cryogenic characteristics, and are therefore often used in aircraft materials, space materials, and the like.

[0003]

In recent years, as electronic devices such as computers and mobile phones have become smaller, thinner, and lighter, electronic components used in them have become increasingly smaller, thinner, and lighter. It has become required. Therefore, as a material for electronic parts, a very thin film having a thickness of 10 μm or less has been required for a polyimide film. However, a conventional polyimide film has an insufficient elastic modulus and is becoming difficult to be thin. Further, it cannot be used as a thin base film for high-density magnetic recording tape requiring high heat resistance and high elastic modulus, and a demand for a polyimide film having high elastic modulus has been increasing.

As a polyimide film having a high elastic modulus exceeding 1000 kg / mm 2, 4,4′-diaminobenzanilide is composed of a diamine component, pyromellitic acid or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. A polyimide film using an acid dianhydride such as a product has been proposed. However, since diaminobenzanilide has a highly polar amide group, it has a problem that the polyimide film obtained has a high water absorption.

[0005] If the water absorption of the polyimide film is high, the dimensional stability of moisture absorption is inferior. In the manufacture of a semiconductor device, a large amount of water absorbed by the film at the time of the encapsulation step is released at a stretch to cause package cracks. It causes problems in terms of processability and reliability. In view of the above circumstances, the present inventors have solved the conventional problems and provided a polyimide film having excellent heat resistance and excellent mechanical properties such as a high elastic modulus and low water absorption. As a result of diligent studies for the purpose of the present invention, the present invention has been reached.

[0006]

The gist of the polyimide film according to the present invention is that of the general formula (1)

[0007]

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(Where R1 is:

[0009]

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(R _Z is at least one selected from H, CH ₃ , Cl, and Br, Z is an integer of 0 to 4), and R 2 is at least one selected from an organic group represented by ,

[0011]

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(R _m and R _n are at least one kind selected from H, CH ₃ , Cl and Br, and Z is an integer of 0 to 4). Show. ), Which has a modulus of 1000 kg / mm2 or more and a water absorption of 1.5% or less (claim 1). The gist of the method for producing a polyimide film according to the present invention is to cast a solution of a polyamic acid that is a precursor of a polyimide film obtained by a polycondensation reaction between tetracarboxylic dianhydrides and diamines. In the method for producing a polyimide film according to claim 1, the weight average molecular weight of the polyamic acid is 150,000 or more (claim 2).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of a polyimide film according to the present invention will be described below. The polyimide film of the present invention has the general formula (A)

[0014]

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(Wherein R1 represents R1 in the general formula (1))
And the same divalent organic group as described above. And a tetracarboxylic dianhydride containing an ester group represented by the following general formula (B): H ₂ N—R ₂ —NH ₂ (B) wherein R ₂ is the same divalent as R 2 in the general formula (1). An aromatic diamine represented by the following formula: can be obtained as a raw material.

The most typical example of the tetracarboxylic dianhydride represented by the general formula (A) is 1,4-hydroquinone dibenzoate-3,3 ', 4,4'-tetracarboxylic acid. Dianhydride, 2,5-dimethyl-1,4-hydroquinone dibenzoate-3,3 ', 4,4'-tetracarboxylic dianhydride, 2,5-dichloro-1,4-hydroquinone dibenzoe -To-3,3 ', 4,4'-tetracarboxylic dianhydride, 2-chloro-1,4-hydroquinone dibenzoate-3,3', 4,4'-tetracarboxylic dianhydride And the like, and one kind or a mixture of two or more kinds can also be used.

The tetracarboxylic dianhydride represented by the general formula (A) is prepared by reacting trimellitic anhydride monochloride with divalent phenols at room temperature or lower, or It can be synthesized by a method in which an acid anhydride and a dimethyl ester of a dihydric phenol are reacted at a high temperature of 200 to 300 ° C. The divalent phenols used as the raw materials include hydroquinone,
-Chlorohydroquinone, 2,5-dichlorohydroquinone, 2,3,5,6-tetrachlorohydroquinone,
2,5-dimethylhydroquinone and the like.

Next, typical examples of the diamine represented by the general formula (B) include 4,4'-diaminobenzanilide,
4,4'-diamino-3,3'-dichlorobenzanilide, 1,4-bis (4-aminophenylcarbamoyl)
Benzene and the like can be mentioned, and one kind or a mixture of two or more kinds can be used. The repeating unit represented by the general formula (1) accounts for at least 50 mol%, preferably 7 mol%, of all repeating units.
It is necessary to contain 0 mol% or more, more preferably 90 mol% or more.

When the content of the repeating unit represented by the general formula (1) is 50% or less, it is difficult to obtain a film having both a high elastic modulus and a low water absorption. The polyimide film of the present invention is not limited to the content form of the repeating unit represented by the general formula (1) in all the repeating units. That is, the copolymer may be a random copolymer or an alternating copolymer. In particular, a copolymer having at least 20 mol%, preferably at least 50 mol% of a segment in which the length of the segment where the repeating unit of the general formula (1) is present in the polymer molecule is preferable in terms of mechanical strength.

The polyimide film containing the repeating unit represented by the general formula (1) produced as described above,
It can have an elastic modulus of 1000 kg / mm2 or more and a water absorption of 1.5% or less. Next, the method for producing a polyimide film according to the present invention will be specifically described.

The polyimide film of the present invention has a precursor represented by the general formula (2)

[0022]

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(Wherein R1 and R2 are the same organic groups as R1 and R2 in the general formula (1)). The polyamic acid solution is prepared by a known method. can do. That is, it is obtained by polymerizing tetracarboxylic dianhydrides and aromatic diamines in an organic polar solvent using substantially equimolar amounts. Tetracarboxylic dianhydrides used to obtain a polyamic acid solution include:
1,4-hydroquinone dibenzoate-3,3 ', 4
4'-tetracarboxylic dianhydride, 2,5-dimethyl-
1,4-hydroquinone dibenzoate-3,3 ', 4
4'-tetracarboxylic dianhydride, 2,5-dichloro-
1,4-hydroquinone dibenzoate-3,3 ', 4
4'-tetracarboxylic dianhydride, 2-chloro-1,4
-Hydroquinone dibenzoate-3,3 ', 4,4'-
Tetracarboxylic dianhydride and the like;
A mixture of two or more species can be used.

Further, one or more kinds of the tetracarboxylic dianhydride represented by the general formula (A) and other tetracarboxylic dianhydrides may be mixed and used. Other tetracarboxylic dianhydrides include 3,3 ′, 4,4 ′
-Diphenyl ether tetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride and the like can be mentioned.

When the tetracarboxylic dianhydride represented by the general formula (A) is mixed with other acid dianhydrides, the mixture is represented by the general formula (A) in terms of low water absorption. It is preferable to use a tetracarboxylic dianhydride having an ester group as a main component. The mechanism of low water absorption of polyimide films using tetracarboxylic dianhydrides containing ester groups is not clear, but the ester groups, which are electron-withdrawing groups, weaken the polarization of imide groups. I guess it is.

As aromatic diamines, 4,4'-diaminobenzanilide, 4,4'-diamino-3,3 '
-Dichlorobenzanilide, 1,4-bis (4-aminophenylcarbamoyl) benzene, and the like, and these can be used alone or in combination of two or more. Diamines represented by the general formula (B) and other diamines
More than one kind can be mixed and used. Other diamines include paraphenylenediamine, 2-chloroparaphenylenediamine, 2,5-dichloroparaphenylenediamine, 4,4′-diamino-2,2′-dimethylbiphenyl, and 4,4′-diamino-2. , 2'-dichlorobiphenyl, 4,4'-diaminodiphenyl ethers and the like. Particularly, from the viewpoint of a high elastic modulus, it is preferable that 4,4′-diaminobenzanilide having few flexible groups and having no substituent is a main component.

The organic solvent used in the polyamic acid formation reaction includes sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, and formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide. , Acetamide solvents such as N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, N-vinyl-2-
Pyrrolidone solvents such as pyrrolidone, phenol, o-,
Phenol-based solvents such as m- or p-cresol can be mentioned, and it is desirable to use these alone or as a mixture, but it is also possible to use aromatic hydrocarbons such as xylene and toluene. It is. It is desirable from the viewpoint of handling that the polyamic acid is dissolved in the organic polar solvent in an amount of 1 to 40% by weight, preferably 5 to 25% by weight.

In the polymerization of polyamic acid, the weight average molecular weight of the polyamic acid is preferably 150,000 or more, more preferably 200,000 or more. When the weight average molecular weight is 150,000 or less, a polyimide film having poor strength can be obtained. In order to obtain the polyimide film of the present invention from the polyamic acid solution, any of (1) a thermal method of thermally dehydrating and imidizing and (2) a chemical method using a dehydrating agent may be used. It is more preferable to use a chemical method that makes it easy to obtain a film having excellent mechanical properties such as strength and strength.

The following is an example of a method for producing a film from a polyamic acid solution. (1) The above polyamic acid solution is cast or coated on a drum or an endless belt to form a film, and the film is formed into a film until it has a self-supporting property.
Dry at a temperature below ℃ for about 5-60 minutes. Then, after peeling it off from the support and fixing the end, the film is dried and imidized by gradually heating to about 100 ° C. to 500 ° C. while restricting the shrinkage of the film, and after cooling, it is removed therefrom. Obtain a polyimide film.

In the above production method, a mixed solution of a polyamic acid solution and a release agent may be used in place of the polyamic acid solution in order to easily peel the self-supporting film from the support. When a polyimide film is obtained by a chemical method, a mixed solution of a polyamic acid solution and a dehydrating agent having a stoichiometric amount or more and a catalytic amount of a tertiary amine may be used instead of the polyamic acid solution.

Examples of the releasing agent include aliphatic ethers such as diethylene glycol dimethyl ether and triethylene glycol dimethyl ether, tertiary amines such as pyridine and picoline, triphenylphosphine and triphenyl. Organic phosphorus compounds such as phosphates are exemplified. Examples of the dehydrating agent include aliphatic or aromatic acid anhydrides such as acetic anhydride and phthalic anhydride. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, and heterocyclic tertiary amines such as pyridine, picoline and isoquinoline.

Further, when the film is dried or imidized, it may be stretched. This is because a film having excellent mechanical properties can be easily obtained by stretching. Also, for the purpose of improving various properties such as adhesiveness, heat resistance, or slipperiness of the film, the film contains fine particles such as titanium oxide, calcium carbonate, alumina, and silica gel, A surface modifier such as a silane coupling agent or a solution containing fine particles and a binder resin may be applied, or a discharge treatment such as a corona treatment or a plasma treatment may be performed.

As described above, the polyimide film according to the present invention has been described, including the manufacturing method. However, the present invention is not limited to only these embodiments, and the present invention is not limited thereto. Various modifications, modifications, and variations can be made based on the knowledge of the above.

[0034]

Next, examples of the present invention will be described in more detail, but the present invention is not limited only to these examples. In the examples, DABA was 4,4'-diaminobenzanilide, and BDABA was 1,4-bis (4-
Aminophenylcarbamoyl) benzene and ODA are
4,4′-diaminodiphenyl ether and TMHQ are 1,4-hydroquinone dibenzoate-3.3 ′, 4,4
4'-tetracarboxylic dianhydride, PMDA is pyromellitic dianhydride, ODPA is 3,3 ', 4,4'-diphenylethertetracarboxylic dianhydride, NMP is N
Represents -methyl-2-pyrrolidone.

Example 1 At room temperature, DABA was placed in a 1-liter three-neck separable flask equipped with a stirrer.
TMHQ 0.095mo in 0.1mol NMP solution
of powder was added, and the mixture was stirred for 1 hour in a nitrogen atmosphere. Then, slowly add TMHQ 0.005 mol to this solution.
Was added to obtain a 15% by weight polyamic acid.

From the polyamic acid solution obtained by the above operation, a polyimide film was prepared by a chemical method. The production of the film is performed as follows. 100
g of polyamic acid solution, 15 g of acetic anhydride, 5 g of β-picoline, and 10 g of NMP were added, and the mixture was sufficiently stirred. The mixture was coated on a PET film with a coater and heated at 80 ° C. for 10 minutes to obtain a film having self-supporting properties. Was. After peeling this film from PET, the end was fixed and continuously heated to 100 ° C. to 450 ° C., and further heated at 450 ° C. for 5 minutes to imidize to obtain a polyimide film having a thickness of 15 μm.

Using the obtained film, a tensile test was performed by AST.
The elastic modulus and strength of the film were determined according to MD-882, and the results are shown in Table 1. Further, the water absorption of the obtained film was measured according to ASTM D-570, and the results are shown in Table 1. Example 2 At room temperature, BDABA 0.1 mol was placed in a 1-liter three-neck separable flask equipped with a stirrer.
0.095 mol of TMHQ was added to 1 liter of the NMP solution, and the mixture was stirred for 1 hour in a nitrogen atmosphere. Next, a NMP solution of 0.005 mol of TMHQ was slowly added to the solution to obtain 15% by weight of polyamic acid.

Using the obtained polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1, and the elastic modulus, strength and water absorption were measured. Table 1 shows the results. Example 3 At room temperature, 0.1 mol of DABA was placed in a 1-liter three-neck separable flask equipped with a stirrer.
0.075mol TMHQ and ODPA in NMP solution
0.02 mol of powder was added, and the mixture was stirred for 1 hour in a nitrogen atmosphere. The solution was then slowly added to TMHQ 0.1.
005 mol of NMP solution was added to obtain 15% by weight of polyamic acid. Using the obtained polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1, and the elastic modulus, strength and water absorption were measured. Table 1 shows the results.

EXAMPLE 4 At room temperature, DABA was placed in a 1-liter three-neck separable flask equipped with a stirrer.
A powder of 0.095 mol of TMHQ was added to an NMP solution of 0.08 mol and 0.02 mol of ODA, followed by stirring for 1 hour in a nitrogen atmosphere. The solution is then slowly added to T
An NMP solution of 0.005 mol of MHQ was added to obtain 15% by weight of polyamic acid. Using the obtained polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1, and the elastic modulus, strength and water absorption were measured. Table 1 shows the results.

(Comparative Example 1) At room temperature, ODA was placed in a 1-liter three-neck separable flask equipped with a stirrer.
TMHQ 0.095mo in 0.1mol NMP solution
of powder was added, and the mixture was stirred for 1 hour in a nitrogen atmosphere. Then, slowly add TMHQ 0.005 mol to this solution.
Was added to obtain a 15% by weight polyamic acid.

Using the obtained polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1, and the elastic modulus, strength and water absorption were measured. Table 1 shows the results. (Comparative Example 2) At room temperature, a powder of 0.095 mol of PMDA was added to an NMP solution of 0.1 mol of ODA in a 1-liter three-neck separable flask equipped with a stirrer, followed by stirring for 1 hour in a nitrogen atmosphere. Then, a NDA solution of 0.005 mol of PMDA was slowly added to this solution to obtain 15% by weight of polyamic acid.

Using the obtained polyamic acid solution, a polyimide film was obtained in the same manner as in Example 1, and the elastic modulus, strength and water absorption were measured. Table 1 shows the results.

[0043]

[Table 1]

[0044]

As described above, the polyimide film according to the present invention has both high elasticity and low water absorption, such as an elastic modulus of 1000 kg / mm2 or more and a water absorption of 1.5% or less.

Claims (2)

[Claims] [Claim 1] The following general formula (1) (Wherein, R1 represents the following: (R _Z is at least one selected from H, CH ₃ , Cl, and Br, Z is an integer of 0 to 4), and at least one selected from the organic groups represented by 3] (R _m and R _n are at least one selected from H, CH ₃ , Cl, and Br, and Z is an integer of 0 to 4). ), Having a modulus of elasticity of 1000 kg
/ Mm2 or more and a water absorption of 1.5% or less. 2. The polyimide film according to claim 1, which is produced by casting a solution of a polyamic acid, which is a precursor of a polyimide film obtained by a polycondensation reaction between tetracarboxylic dianhydrides and diamines. Wherein the weight average molecular weight of the polyamic acid is 150,000 or more.