JP3456256B2 - Polyimide copolymer and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a polyimide having excellent heat resistance, high mechanical strength, thermal dimensional stability and low hygroscopicity, which is suitable as a base material for fine patterned flexible printed wiring boards and the like. The present invention relates to a copolymer and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
Polyimide resin is known to have excellent heat resistance, chemical resistance, electrical properties, mechanical properties, and other excellent properties, and is particularly useful for various applications such as electrical insulation films that require heat resistance. Widely used. However, the polyimide resin is superior in heat resistance to other plastics, but has a significantly high water absorption. Therefore, it has a drawback that dimensional stability and insulation are deteriorated.

In recent years, there has been an increasing demand for polyimide resins having excellent low hygroscopicity and excellent mechanical strength, and various studies have been conducted. Among such attempts, many attempts are made to improve low hygroscopicity by using an aromatic diamine having a hydrophobic group or an aromatic tetracarboxylic dianhydride. However, in each of these approaches, the mechanical properties, in particular the elastic modulus and the tensile strength, tend to decrease in exchange for the improvement of the low hygroscopicity, and both the low hygroscopicity and the mechanical properties are reduced. I was not satisfied.

The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a polyimide copolymer having excellent heat resistance, high thermal dimensional stability, high mechanical strength and low hygroscopicity, and a method for producing the same.

[0005]

Means and Actions for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, 4,4 '
-Bis (4-aminobenzamido) -3,3'-dimethylbiphenyl and 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane or 2,2-
A polyamic acid copolymer obtained by polymerizing an aromatic diamine containing bis [4- (4-aminophenoxy) phenyl] propane as a main component and an aromatic tetracarboxylic dianhydride is thermally and chemically By dehydration ring closure to
A polyimide copolymer containing a repeating unit (A) represented by the following general formula (1) and a repeating unit (B) represented by the following general formula (2) as main constitutional units, preferably the following repeating unit (A ) And the following repeating unit (B) in a molar ratio of (A) /
(B) A polyimide copolymer containing repeating units of 10/90 to 90/10 is obtained, and the polyimide copolymer has excellent low hygroscopicity and excellent mechanical strength. That is, the present invention has been completed.

[0006]

[Chemical 2] (However, in the formula, R ¹ represents a tetravalent aromatic group, and R ² represents CH ₃
Or CF ₃ is shown. )

Therefore, the present invention provides a polyimide copolymer containing a repeating unit (A) represented by the general formula (1) and a repeating unit (B) represented by the general formula (2) as main constituent units. In combination, preferably the repeating unit (A) and the repeating unit (B) are in a molar ratio of (A) / (B) = 10/90 to 90.
/ 10 polyimide copolymer and 4,4'-bis (4-aminobenzamido) -3,3'-dimethylbiphenyl and 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoro An aromatic diamine containing propane or 2,2-bis [4- (4-aminophenoxy) phenyl] propane as a main component is polymerized with an aromatic tetracarboxylic acid dianhydride to obtain a polyamic acid. A repeating unit (A) represented by the general formula (1) and a repeating unit (B represented by the general formula (2), which are characterized in that the polyamic acid copolymer is thermally and chemically dehydrated and ring-closed. )
Provided is a method for producing a polyimide copolymer containing and as a main constituent unit.

The present invention will be described in more detail below. The polyimide copolymer of the present invention has the following general formula (1).
The total amount of the repeating unit (A) represented by and the repeating unit (B) represented by the following general formula (2) is 100 mol%, and the repeating unit (A) and the repeating unit (B) are mols. Ratio (A) /
(B) = 10/90 to 90/10.

[0009]

[Chemical 3] (However, in the formula, R ¹ represents a tetravalent aromatic group, and R ² represents CH ₃
Or CF ₃ is shown. )

R ¹ in the above formula is a tetravalent aromatic group,
This is derived from the main skeleton of tetracarboxylic dianhydride described later.

Here, the repeating unit (A) and the repeating unit (B) have a molar ratio (A) in the polyimide copolymer.
/ (B) = 10/90 to 90/10, especially 25/75 to
It is preferably present in a ratio of 75/25. When the molar ratio of the repeating unit (A) exceeds 90%, the effect of improving the water absorption of the polyimide copolymer cannot be sufficiently obtained, and the flexibility decreases. On the other hand, when the molar ratio of the repeating unit (B) exceeds 90%, the mechanical strength, elastic modulus and thermal dimensional stability of the polyimide copolymer become very low.

[0012]

The above-mentioned polyimide copolymer is a high molecular weight polymer, and its viscosity as a polyamic acid is, for example, 0.5.
Measurement temperature 30 when measured in g / 100 ml DMF
The logarithmic viscosity at 0 ° C. is preferably 0.5 to 5.0 dl / g.

The above polyimide copolymer is obtained by polymerizing an aromatic diamine and an aromatic tetracarboxylic dianhydride to obtain a polyamic acid copolymer, and the polyamic acid copolymer is thermally or chemically prepared by a known method. It can be produced by dehydration ring closure (imidization).

In the present invention, as the aromatic diamine, 4,4'-bis (4-aminobenzamide) is used.
-3,3'-dimethylbiphenyl and 2,2-bis [4
-(4-Aminophenoxy) phenyl] hexafluoropropane or 2,2-bis [4- (4-aminophenoxy) phenyl] propane is used as a main component. In addition, 4,4′-bis (4-aminobenzamide) -3,
3'-dimethylbiphenyl and 2,2-bis [4- (4
-Aminophenoxy) phenyl] hexafluoropropane or 2,2-bis [4- (4-aminophenoxy) phenyl] propane is mixed at a molar ratio of 10/90.
It is preferable to be 90 to 90/10, particularly 25/75 to 75/25.

[0016]

On the other hand, as the aromatic tetracarboxylic dianhydride, specifically, pyromellitic dianhydride, 3,3 ',
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, bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 1,1-bis (3,4-carboxyphenyl) ethane dianhydride, 3,
4,9,10-berylenetetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride,
2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenylene tetracarboxylic dianhydride and the like can be mentioned, and one of these can be used alone or two or more can be used. It can be used in combination.

In the polymerization reaction of the aromatic diamine and the aromatic tetracarboxylic dianhydride, both compounds are mixed with 100 parts of the aromatic dicarboxylic acid dianhydride per 100 aromatic diamine mixture in an organic polar solvent in a molar ratio. It is desirable to mix them in a proportion of 95 to 105, especially equimolar.

Further, as the organic polar solvent, for example, sulfoxide-based solvent such as dimethyl sulfoxide, N, N
Formamide solvents such as dimethylformamide, N, N-diethylformamide, acetamide solvents such as N, N-dimethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol , Phenol solvent such as o-, m- or p-cresol, xylenol, halogenated phenol, and catechol, or hexamethylphosphoramide, γ-butyrolactone, and the like. These may be used alone or in combination of two or more, and may also be used in combination with an aromatic hydrocarbon-based organic nonpolar solvent such as xylene or toluene. The amount of the above organic polar solvent used is not particularly limited, but the aromatic diamine is such that the polyamic acid copolymer obtained by the polymerization reaction is dissolved in the organic polar solvent in an amount of 5 to 30% by weight, particularly 10 to 20% by weight. It is desirable to determine the amounts of the aromatic tetracarboxylic dianhydride and organic polar solvent used.

The polymerization reaction conditions are 0 to 70 ° C., especially 0 to
It is preferable to carry out the reaction at a temperature of 30 ° C. for 1 to 40 hours, particularly 2 to 16 hours, and a polyamic acid copolymer can be obtained more efficiently by this polymerization reaction.

Next, the dehydration ring closure of the polyamic acid copolymer can be carried out by an ordinary method, and thermal or chemical dehydration ring closure (imidization) can be preferably adopted. Here, as the thermal dehydration ring-closing method, 5 at 200 to 500 ° C.
A method of heating for 120 minutes is preferable.

A method using a dehydrating agent and a catalyst is suitable for chemically dehydrating and ring-closing the polyamic acid copolymer. In this case, examples of the dehydrating agent include aliphatic acid anhydrides, aromatic acid anhydrides, N, N'-dialkylcarbodiimides, lower fatty acid halides, halogenated lower fatty acid halides, halogenated lower fatty acid anhydrides, allyl phosphite. Examples thereof include phonic acid dihalide and thionyl halide. These can be used alone or in combination of two or more. The amount of the dehydrating agent used is preferably about 0.1 to 10 mols, and particularly preferably 0.5 to 4 mols per repeating unit of the polyamic acid.

Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, β-picoline and isoquinoline. These can be used alone or in combination of two or more.
The amount of the catalyst used is preferably about 0.01 to 4 mols, and particularly preferably 0.1 to 2 mols per repeating unit of polyamic acid.

The reaction conditions for the above chemical dehydration ring closure are as follows:
0.2 to 20 hours at 20 to 400 ° C., especially 50 to 350
Preference is given to 0.5 to 5 hours at 0 ° C.

To obtain a polyimide copolymer in the form of a film, a solution of the above polyamic acid copolymer in an organic solvent is cast or coated on a support such as an endless belt to form a film, and the film is 100 to 150. Dry at 0 ° C and add 10-
A polyamic acid self-supporting membrane containing 30% is obtained.
Then, the film is peeled off from the support, the ends are fixed, and then heated to about 200 to 250 ° C. to remove the solvent, and further dehydrated and imidized at 200 to 500 ° C. to have a thickness of 10 to 150 μm. Can be obtained.

[0026]

The polyimide film composed of the polyimide copolymer of the present invention is excellent in various properties such as heat resistance, and has high mechanical strength and thermal dimensional stability.
Moreover, since it has low hygroscopicity, it is suitable as a film material such as an electrically insulating material or a fine patterned flexible printed circuit board. Further, according to the production method of the present invention, the polyimide copolymer can be industrially advantageously produced.

[0027]

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

Reference Example First, as shown below, 4,4'-
Bis (4-aminobenzamido) -3,3′-dimethylbiphenyl was synthesized.

3,3 'in 300 ml of tetrahydrofuran
-Dihydroxy-4,4'-diaminobiphenyl 37.
1 g (0.175 mol) and triethylamine 38.6
After dissolving g (0.381 mol) and cooling to 0 ° C, a solution of 68.2 g (0.368 mol) of p-nitrobenzoyl chloride in 150 ml of tetrahydrofuran has a reaction liquid temperature of 10 ° C or lower. So that it was dripped.
Then, it returned to room temperature and continued stirring for 2 hours.

Then, the precipitate was filtered, washed with tetrahydrofuran, further washed with water and methanol, and then dried to obtain 4,4'-bis (4-nitrobenzamide)-.
Yellow-white crystals of 3,3′-dimethylbiphenyl were obtained. The yield was 89.0 g (yield 99.6%). The crude crystal was recrystallized from N, N-dimethylformamide to obtain a pure product.

4,4'-bis (4-nitrobenzamide) -obtained above in 1,000 ml autoclave
3,3'-Dimethylbiphenyl 15.0 g (0.029
4 mol) was charged together with 3 g of 5% Pd / C and 500 ml of dimethylformamide. Hydrogen was introduced with vigorous stirring at 60 ° C., and stirring was continued until hydrogen absorption was no longer observed.

After cooling, the catalyst was removed by filtration, concentrated under reduced pressure and poured into 500 ml of water. The precipitate was filtered, washed with water and methanol and dried under reduced pressure to obtain 4,4'-bis (4-aminobenzamide). ) -3,3'-Dimethylbiphenyl white crystals were obtained. The yield was 13.2 g (yield 99.6%). The crude crystal was recrystallized with a mixed solvent of dimethylformamide / methanol to obtain a pure product.

Example 1 A 500 ml flask was charged with N,
259.0 g of N-dimethylformamide (DMF) was added, and 4,4′-bis (4-aminobenzamide) -3,3′-dimethylbiphenyl 4.5 while flowing nitrogen gas.
1 g (0.010 mol) and 2,2-bis [4- (4
15.55 g (0.030 mol) of -aminophenoxy) phenyl] hexafluoropropane was dissolved in N, N-dimethylformamide. Next, 8.72 g (0.040 mol) of pyromellitic dianhydride was added and reacted at 25 ° C. for 3 hours.

Next, these polyamic acid solutions are thinly spread on a glass plate with an applicator, and then 110% in an oven.
After drying for 60 minutes at ℃, peel it off and fix it on the iron frame.
Desolvation imidization was carried out at 00 ° C. for 60 minutes and then at 300 ° C. for 60 minutes to obtain a film having a thickness of about 25 μm. The characteristics of the film are shown in Table 1.

Example 2 In a 500 ml flask, N,
252.9 g of N-dimethylformamide (DMF) was added, and 4,4′-bis (4-aminobenzamide) -3,3′-dimethylbiphenyl 9.0 was added while flowing nitrogen gas.
1 g (0.020 mol) and 2,2-bis [4- (4
10.37 g (0.020 mol) of -aminophenoxy) phenyl] hexafluoropropane was dissolved in N, N-dimethylformamide. Next, after adding 8.72 g (0.040 mol) of pyromellitic dianhydride and reacting at 25 ° C. for 3 hours, a film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

Example 3 A 500 ml flask was charged with N,
246.8 g of N-dimethylformamide (DMF) was added, and 4,4′-bis (4-aminobenzamide) -3,3′-dimethylbiphenyl was added while flowing nitrogen gas.
52 g (0.030 mol) and 2,2-bis [4-
5.18 g (0.010 mol) of (4-aminophenoxy) phenyl] hexafluoropropane was dissolved in N, N-dimethylformamide. Next, add 8.72 g (0.040 mol) of pyromellitic dianhydride, and add 25 ° C.
After reacting for 3 hours, a film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

[Example 4] A 500 ml flask was charged with N,
233.4 g of N-dimethylformamide (DMF) was added, and 4,4′-bis (4-aminobenzamide) -3,3′-dimethylbiphenyl 9.0 was added while flowing nitrogen gas.
1 g (0.020 mol) and 2,2-bis [4- (4
-Aminophenoxy) phenyl] propane 8.21 g
(0.020 mol) was dissolved in N, N-dimethylformamide. Next, 8.72 g of pyromellitic dianhydride
(0.040 mol) was added and reacted at 25 ° C. for 3 hours, and then a film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

Example 5 A 500 ml flask was charged with N,
237.1 g of N-dimethylformamide (DMF) was added, and 4,4′-bis (4-aminobenzamide) -3,3′-dimethylbiphenyl was added while flowing nitrogen gas.
52 g (0.030 mol) and 2,2-bis [4-
(4-Aminophenoxy) phenyl] propane 4.10
g (0.010 mol) was dissolved in N, N-dimethylformamide. Next, pyromellitic dianhydride 8.72
After adding g (0.040 mol) and reacting at 25 ° C. for 3 hours, a film was obtained by the same method as in Example 1.
The characteristics of the film are shown in Table 1.

Comparative Example 1 A 500 ml flask was charged with N,
210.6 g of N-dimethylformamide (DMF) was added, and 4,4'-bis (4-aminobenzamide) -3,3'-dimethylbiphenyl 15.
68 g (0.035 mol) was added and dissolved in DMF. Next, 7.63 g (0.03 g of pyromellitic dianhydride)
5 mol) was added and reacted at 25 ° C. for 3 hours, and then a film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

Comparative Example 2 A 500 ml flask was charged with N,
232.1 g of N-dimethylformamide (DMF) was added, and 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane 1 was added while flowing nitrogen gas.
8.15 g (0.035 mol) was added and dissolved in DMF. Next, 7.63 g of pyromellitic dianhydride (0.
(035 mol) and reacted at 25 ° C. for 3 hours,
A film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

Comparative Example 3 A 500 ml flask was charged with N,
N-Dimethylformamide (DMF) (197.9 g) was added, and 2,2-bis [4- (4-aminophenoxy) phenyl] propane (14.36 g) was introduced while flowing nitrogen gas.
(0.035 mol) was added and dissolved in DMF. Next, 7.63 g of pyromellitic dianhydride (0.035 mo
l) was added and reacted at 25 ° C. for 3 hours, and then a film was obtained by the same method as in Example 1. The characteristics of the film are shown in Table 1.

Mechanical properties of the obtained film,
The linear expansion coefficient was measured as follows. The results are shown in Table 1. Mechanical Properties (Tensile Strength, Elastic Modulus, Elongation ) Measured based on ASTM D882-88. Linear expansion coefficient Using a thermal analyzer TMA-7000 manufactured by Vacuum Riko Co., Ltd., an average value of linear expansion coefficients at 150 to 200 ° C was obtained at a temperature rising rate of 5 (° C / min). Water absorption rate The polyimide film was left at 90% RH for 24 hours, and the weight before and after that was measured to determine the water absorption rate. Logarithmic viscosity The polyamic acid concentration was 0.5 g / 100 ml DMF, and the measurement temperature was 30 ° C.

[0043]

[Equation 1]

[0044]

[Table 1]

From the results shown in Table 1, it was confirmed that the polyimide copolymer of the present invention has excellent mechanical strength, low linear expansion coefficient and water absorption, high elastic modulus and flexibility.

Front page continuation (72) Inventor Atsushi Sugitani, Higashiwada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Shin-Etsu Chemical Co., Ltd., Polymer Functional Materials Research Laboratory (72) Inventor Masahiro Yuyama, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Wada No. 1 Shin-Etsu Chemical Co., Ltd. Polymer Functional Materials Research Laboratory (56) Reference JP-A-57-181146 (JP, A) JP-A-58-157190 (JP, A) JP-A-61-143434 ( JP, A) JP 62-70424 (JP, A) JP 63-199237 (JP, A) JP 63-221126 (JP, A) JP 63-239998 (JP, A) JP JP-A-5-247210 (JP, A) JP-A-6-175138 (JP, A) JP-A-6-345868 (JP, A) JP-A-7-33876 (JP, A) JP-A-7-62095 (JP , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 73/00-73/26 CAPLUS (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. The total amount of the repeating unit (A) represented by the following general formula (1) and the repeating unit (B) represented by the following general formula (2) is 100 mol%, and the repeating unit ( (A) and the repeating unit (B) in a molar ratio of (A) / (B) = 10 / 90-
A polyimide copolymer containing 90/10. [Chemical 1] (However, in the formula, R ¹ represents a tetravalent aromatic group, and R ² represents CH ₃
Or CF ₃ is shown. ) 2. 4,4′-bis (4-aminobenzamido) -3,3′-dimethylbiphenyl and 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane or 2,2- Aromatic diamine containing bis [4- (4-aminophenoxy) phenyl] propane as a main component and tetracarboxylic dianhydride are polymerized to obtain a polyamic acid copolymer, and then the polyamic acid copolymer. The method for producing a polyimide copolymer according to claim 1, wherein the dehydration ring closure is carried out thermally or chemically.