JP3208988B2 - Polyamic acid solution and method for producing polyimide - 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 solution for obtaining a polyimide by chemically dehydrating and cyclizing a polyamic acid and a method for producing a polyimide using the polyamic acid solution.

[0002]

2. Description of the Related Art Conventionally, polyimide is excellent in heat resistance, chemical resistance, mechanical strength, electric characteristics, etc., and its film is used for heat-resistant materials, laminates, flexible printed boards, and the like. Have been.

[0003] As a method for producing a polyimide film, a method is generally employed in which a polyamic acid is obtained in a solution, and the obtained polyamic acid is chemically or thermally dehydrated and ring-closed. As this chemical dehydration method, a method using a dehydrating agent such as acetic anhydride and a dehydrating catalyst such as isoquinoline has been proposed (JP-B-36-10999, JP-B-37-97,
Japanese Patent Publication No. 39-30060), it is known that hydrolysis does not occur due to heat as compared with the thermal conversion method, so that a polyimide having good orientation and good physical properties can be obtained.

[0004]

However, conventionally,
The dehydration catalyst used in the chemical dehydration imidization method allows the imidization to proceed rapidly even at room temperature.
It gels in a few minutes to tens of minutes and is very difficult to store. Therefore, it is difficult to produce a polyimide film continuously for a long time using the chemical dehydration imidization method, which is inconvenient in production.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a polyamic acid solution having a good storage stability while obtaining a polyimide having good physical properties by a chemical dehydration method. It is an object of the present invention to provide a method for obtaining the compound advantageously in production.

[0006]

Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, in a chemical dehydration method of dehydrating polyamic acid in the presence of a dehydrating agent and a dehydrating catalyst to obtain a polyimide, while using a fatty acid anhydride as a dehydrating agent, It has been found that it is effective to use the following polycyclic nitrogen-containing heterocyclic compound containing two or more nitrogen atoms.

That is, the polycyclic nitrogen-containing heterocyclic compound containing two or more nitrogen atoms has low catalytic activity as a dehydration catalyst at around room temperature and rapidly increases at approximately 60 ° C. Therefore, the polyamic acid solution containing a dehydrating agent and this dehydrating catalyst is stable around room temperature, has good storage stability, and has a drying temperature at which a solvent is evaporated to obtain a self-supporting film. It has been found that when heated to a high temperature, a dehydration reaction occurs rapidly to give a polyimide which is stable in production and has good physical properties by a chemical dehydration method, and the present invention has been accomplished.

Accordingly, the present invention provides a polyamic acid solution containing a dehydrating agent and a dehydrating catalyst, wherein a fatty acid anhydride is used as a dehydrating agent and 1,10-phenanthroline and 9-methyl-1,10- are used as a dehydrating catalyst. Phenanthroline, 2,4-dimethyl-1,10-phenanthroline, 2,4,7,9-tetramethyl-1,10-phenanthroline, 2,3,8,9-tetramethyl-1,10
-Phenanthroline, 1,7-phenanthroline, 8-
Methyl-1,7-phenanthroline, 6-methyl-1,
Polyamic acid solution characterized by using a material selected from 7-phenanthroline, 2,8-dimethyl-1,7-phenanthroline, 4,7-phenanthroline, 3-methyl-4,7-phenanthroline, pyridine and naphthyridine. And a method for producing a polyimide, comprising heating the polyamic acid solution and dehydrating and ring-closing the polyamic acid.

Hereinafter, the present invention will be described in more detail. The polyamic acid solution of the present invention contains a dehydrating agent and a specific dehydration catalyst as described above.

In the present invention, as the polyamic acid solution, all those used for producing polyimide can be used.
Although not particularly limited, for example, it can be obtained by reacting an aromatic tetracarboxylic dianhydride with an aromatic diamine in an organic polar solvent.

In this case, examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride Anhydride, bis (3,4-
Dicarboxyphenyl) propane dianhydride, bis (3
4-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride , 2,3,6,7-anthracenecarboxylic dianhydride, 1,2,7,8-phenylenetetracarboxylic dianhydride and the like. One of these can be used alone or two or more of them can be used. Can be used in combination.

Examples of the aromatic diamine include 4,4'-diaminodiphenyl ether, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-diaminodiphenylsulfone, and 3,3'-diaminodiphenyl. Sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4 -Aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenyl) benzene, bis [4- (4-aminophenoxy) phenyl] ether, 4,4 ′ -Diaminodiphenylmethane,
Bis (3-ethyl-4-aminophenyl) methane, bis (3-methyl-4-aminophenyl) methane, bis (3
-Chloro-4-aminophenyl) methane, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-dimethoxy-4,4'-diaminodiphenyl, 3,3'-dimethyl- 4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 2,2 ', 5,5'-tetrachloro-
4,4'-diaminobiphenyl, 3,3'-dicarboxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 4,4'-diaminodiphenylsulfide, 3, 3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-
Diaminobiphenyl, 4,4'-diaminooctafluorobiphenyl, 2,4-diaminotoluene, metaphenylenediamine, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-
Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) propane,
2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-hydroxy-4-aminophenyl) propane, 2,2-bis (3-hydroxy-4
-Aminophenyl) hexafluoropropane, 9,9-
Bis (4-aminophenyl) -10-hydro-anthracene, ortho-tolidine sulfone, and the like,
One of these can be used alone, or two or more can be used in combination.

Further, examples of the organic polar solvent include sulfoxide solvents such as dimethylsulfoxide and diethylsulfoxide, N, N-dimethylformamide, N, N
-Formamide solvents such as diethylformamide,
Acetamide solvents such as N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-
Pyrrolidone solvents such as pyrrolidone and N-vinyl-2-pyrrolidone; phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenols and catechol; or hexamethylphosphoramide, γ- Butyrolactone and the like can be mentioned. In use, these can be used alone or in combination of two or more, and further, a part of aromatic hydrocarbons such as xylene and toluene can be used.

In the reaction, it is preferable to dissolve the reaction components in such an amount that the obtained polyamic acid becomes 5 to 30% by weight, particularly 10 to 20% by weight in an organic solvent. The reaction temperature is 0 to 70 ° C, particularly 0 to 30 ° C, and the reaction time is 2 to
It is preferable to carry out the reaction for 20 hours, especially about 3 to 8 hours.

The polyamic acid solution of the present invention is characterized in that a dehydrating agent and a specific dehydration catalyst are blended in such a polyamic acid solution.

In this case, as the dehydrating agent, for example, fatty acid anhydrides such as acetic anhydride and propionic anhydride are used.
Particularly, acetic anhydride is preferred. The amount of the dehydrating agent added is 0.1 to 5 mol per 1 mol of the amic acid unit in the polyamic acid,
Preferably, it is in the range of 0.5 to 2 mol.

In the present invention, as a dehydration catalyst, as described above, polycyclic nitrogen-containing heterocyclic compounds containing two or more nitrogen atoms include 1,10-phenanthroline, 9-methyl-1,10-phenanthroline, 2,4-dimethyl-
1,10-phenanthroline, 2,4,7,9-tetramethyl-1,10-phenanthroline, 2,3,8,9
-Tetramethyl-1,10-phenanthroline, 1,7
-Phenanthroline, 8-methyl-1,7-phenanthroline, 6-methyl-1,7-phenanthroline, 2,
One of 8-dimethyl-1,7-phenanthroline, 4,7-phenanthroline, 3-methyl-4,7-phenanthroline, piperidine and naphthyridine is used alone or in combination of two or more. Among these, 1,10-phenanthroline is preferred from the viewpoint of availability.

The amount of the dehydration catalyst to be added is in the range of 0.1 to 5 mol, preferably 0.5 to 2 mol, per 1 mol of the amic acid unit in the polyamic acid. If the addition amount is less than 0.1 mol, the effect as a catalyst is not sufficient, and the catalyst effect may not be obtained even when the temperature is increased. On the other hand, if it exceeds 5 mol, the boiling point of the catalyst is high and it is difficult to remove the catalyst. Therefore, the catalyst remains in the polyimide even after heating to complete the imidization, which may deteriorate the properties of the film. is there.

The polyamic acid solution of the present invention containing the above-described dehydrating agent and dehydration catalyst is stable at room temperature, but undergoes a chemical dehydration reaction upon heating to easily produce polyimide.

For example, when producing a polyimide film, the polyamic acid solution of the present invention is cast on a smooth surface,
Heating at 0 to 120 ° C. for 5 to 60 minutes to obtain a self-supporting polyamic acid film with some degree of imidization, fixing the film to an iron frame, and heating at 150 to 200 ° C. for 30 to 9
After completely removing the solvent for 0 minutes, the polyimide film can be obtained by further heating at 300 to 450 ° C. for about 1 to 90 minutes for complete imidization.

[0021]

The polyamic acid solution of the present invention can provide a polyimide having good physical properties by a chemical dehydration method, and is stable at room temperature and has good storage stability.

Further, according to the method for producing a polyimide of the present invention, since a polyamic acid solution having good storage stability is used, the polyimide can be advantageously obtained in production.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

First, polyamic acid solutions used in Examples and Comparative Examples were prepared. <Preparation of polyamic acid solution> N, N-dimethylformamide (DMF) 941.3 was placed in a 2000 ml flask.
g, 4,4'-diaminodiphenyl ether 50.06
g (0.25 mol) was charged, and the mixture was stirred while nitrogen gas was introduced to completely dissolve 4,4′-diaminodiphenyl ether. Next, pyromellitic dianhydride 54.5
3 g (0.25 mol) was added at a temperature of 25 ° C. while suppressing heat generation, and the mixture was stirred under nitrogen gas for 3 hours to obtain a polyamic acid solution having a polymer concentration of 10%.

Example 1 A 300 ml flask was charged with 200 g of the above polyamic acid solution, while 7.3 ml of acetic anhydride was used.
21 g (1.5 mol per amic acid unit), and 1,
4.738 g (0.5 mol per amic acid unit) of 10-phenanthroline monohydrate was mixed well in a small amount of DMF, and this was mixed with polyamic acid kept at temperatures of 30 ° C, 50 ° C and 100 ° C. The solutions were each added to the solution while stirring, and their viscosity changes were measured. The point at which a sharp increase in the viscosity occurred was defined as the gel time, and the gel time was measured.

Comparative Example 1 The gelation time was measured in the same manner as in Example 1, except that isoquinoline was used instead of 1,10-phenanthroline monohydrate. The amount of acetic anhydride was set to 1.0 mol with respect to the amic acid unit so as to be substantially equal to the amount of acetic anhydride added in Example 1.

Comparative Example 2 Gelation time was measured in the same manner as in Example 1 except that β-picoline was used instead of 1,10-phenanthroline monohydrate. The amount of acetic anhydride was set to 1.0 mol with respect to the amic acid unit so as to be substantially equal to the amount of acetic anhydride added in Example 1.

The measured gelation times are shown in Table 1, and the values of the activation energies obtained from the results of the gelation times are also shown in the table.

[0029]

[Table 1]

From the results shown in Table 1, it can be seen that the polyamic acid solution using 1,10-phenanthroline as a dehydration catalyst is stable at room temperature, but the dehydration reaction rapidly proceeds as the temperature rises.

Example 2 200 g of the above polyamic acid solution was placed in a 500 ml flask while 7.3 ml of acetic anhydride was used.
21 g (1.5 mol per amic acid unit), and 1,
After 4.738 g (0.5 mol per amic acid unit) of 10-phenanthroline monohydrate was mixed well in a small amount of DMF, this was added to a polyamic acid solution near room temperature, and stirred for 2 hours.

Next, this polyamic acid solution was thinly spread on a glass plate with an applicator and placed in an oven at 110 ° C.
For 30 minutes, and the resulting supportive film was fixed on an iron frame, and heated at 200 ° C. for 60 minutes and further at 350 ° C. for 60 minutes to completely remove the solvent and imidize to obtain a film.

The tensile strength and linear expansion coefficient of the obtained film were measured. Table 2 shows the results.

Example 3 The amount of acetic anhydride added was 21.9.
36 g (4.5 mol per amic acid unit), 1,10
-Add 18.952 g of phenanthroline monohydrate
A film was obtained in the same manner as in Example 2 except that the amount was 2.0 mol per amic acid unit, and physical properties were measured in the same manner. The results are also shown in Table 2.

Comparative Example 3 The same operation as in Example 2 was carried out except that isoquinoline was used as the dehydration catalyst, but gelled during the stirring.

Comparative Example 4 The temperature of the polyamic acid solution was set to 1
A film was obtained in the same manner as in Comparative Example 2 except that stirring and mixing were performed at 0 ° C., and physical properties were measured in the same manner. The results are also shown in Table 2.

Comparative Example 5 A polyimide film was obtained by heating in the same manner as in Example 2 without adding a dehydrating agent and a dehydrating catalyst to the above polyamic acid solution to obtain a polyimide film, and physical properties were measured in the same manner. The results are also shown in Table 2.

[0038]

[Table 2]

From the results shown in Table 2, the polyimide obtained by the method of the present invention has excellent tensile strength, low coefficient of linear expansion,
It has good physical properties.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Sugitani 1-family Towada, Kazu-gun, Kashima-gun, Ibaraki Pref. Shin-Etsu Chemical Co., Ltd. 1 Kamisucho, Towada, Shin-Etsu Chemical Co., Ltd. Inside the Polymer Functional Materials Laboratory (56) References JP-A-60-15426 (JP, A) JP-A-60-15427 (JP, A) JP-A Sho 59-223727 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 73/00-73/26

Claims (2)

(57) [Claims] In a polyamic acid solution containing a dehydrating agent and a dehydrating catalyst, a fatty acid anhydride is used as a dehydrating agent, and 1,10-phenanthroline is used as a dehydrating catalyst.
9-methyl-1,10-phenanthroline, 2,4-dimethyl-1,10-phenanthroline, 2,4,7,9
-Tetramethyl-1,10-phenanthroline, 2,
3,8,9-tetramethyl-1,10-phenanthroline, 1,7-phenanthroline, 8-methyl-1,7-
Phenanthroline, 6-methyl-1,7-phenanthroline, 2,8-dimethyl-1,7-phenanthroline,
A polyamic acid solution using a material selected from 4,7-phenanthroline, 3-methyl-4,7-phenanthroline, pyridin and naphthyridine. 2. A method for producing a polyimide, comprising heating the polyamic acid solution according to claim 1 to dehydrate and ring-close the polyamic acid.