JPH07292103A - Polyimide copolymer and method for producing the same - Google Patents

Abstract

(57) [Summary] [Structure] A polyamide obtained by polymerizing an aromatic diamine containing 4,4'-bis (4-aminophenoxy) biphenyl and p-phenylenediamine as main components and pyromellitic dianhydride. An acid copolymer is obtained, and then the polyamic acid copolymer is thermally or chemically dehydrated and cyclized to form a repeating unit (A) represented by the following formula and a repeating unit (B) represented by the following formula. A polyimide copolymer containing and as constituent units,
Preferably, a polyimide copolymer containing a repeating unit in which the following repeating unit (A) and the following repeating unit (B) have a molar ratio of (A) / (B) = 25/75 to 80/20 is obtained. [Chemical 1] [Effect] The polyimide copolymer of the present invention has excellent mechanical properties, a coefficient of linear expansion equivalent to that of a metal (eg, copper), and a low water absorption.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyimide having excellent mechanical properties, a coefficient of linear thermal expansion equivalent to that of a metal, and low water absorption, which is suitable as a base material for a fine patterned flexible printed wiring board. The present invention relates to a copolymer and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyimide resins have been extremely superior in heat resistance and chemical resistance.
It is known to have electrical characteristics, mechanical characteristics, and other excellent characteristics. For example, Japanese Patent Publication No. 36-10999.
Polyimides obtained from 4,4-diaminodiphenyl ether and pyromellitic dianhydride, which are found in Japanese Patent Laid-Open Publication No. Hei 10 (1999) -163, are well known.

However, the conventional polyimide resin of this kind has a large linear expansion coefficient of about 3 × 10 ^-5 (cm / cm / ° C.), is poor in thermal dimensional stability, and warps when laminated with a metal or the like. There is a problem that curling occurs, and because the water absorption is high, the dimensional change of the polyimide film occurs due to the change of humidity, so that the electrical characteristics deteriorate.

On the other hand, in recent years, there has been an increasing demand for a polyimide resin having a high heat resistance and a high mechanical strength, which is excellent in the thermal stability of the polyimide resin, and a more excellent thermal dimensional stability. Therefore, various studies have been conducted. Among such attempts, efforts to improve mechanical properties, thermal dimensional stability, etc. and reduce water absorption by using two or more kinds of aromatic diamines are described in, for example, JP-A-60-203638. See, for example, JP-A-61-143433. However, none of these approaches was still fully satisfactory in terms of thermal dimensional stability and water absorption.

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 mechanical strength, a linear expansion coefficient equivalent to that of a metal, and a low water absorption, and a method for producing the same.

[0006]

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 '
-Aromatic diamine containing bis (4-aminophenoxy) biphenyl and p-phenylenediamine as main components and pyromellitic dianhydride are polymerized to obtain a polyamic acid copolymer, and then the polyamic acid copolymer A polyimide copolymer containing a repeating unit (A) represented by the following formula and a repeating unit (B) represented by the following formula as constitutional units by thermally or chemically dehydrating and ring-closing the combined product, preferably The following repeating unit (A) and the following repeating unit (B) have a molar ratio of (A) /
(B) A polyimide copolymer containing repeating units of 25/75 to 80/20 is obtained, and the polyimide copolymer has excellent mechanical strength and a linear expansion coefficient equivalent to that of a metal. The inventors have found that they have a low water absorption rate and, therefore, can be effectively used as a base material for a fine patterned flexible printed wiring board or the like, and completed the present invention.

[0007]

[Chemical 2]

Therefore, the present invention provides a polyimide copolymer containing a repeating unit represented by the above formula (A) and a repeating unit represented by the above formula (B) as main constituent units, and 4,4 '.
-Aromatic diamine containing bis (4-aminophenoxy) biphenyl and p-phenylenediamine as main components and pyromellitic dianhydride are polymerized to obtain a polyamic acid copolymer, and then the polyamic acid copolymer Provided is a method for producing the above polyimide copolymer, which comprises dehydrating and ring-closing the polymer.

Hereinafter, the present invention will be described in more detail. The polyimide copolymer of the present invention is as follows.
A repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B) are main constituent units.

[0010]

[Chemical 3]

Here, the repeating unit (A) and the repeating unit (B)
Is the molar ratio (A) / (B) in the polyimide copolymer.
= 25/75 to 80/20, particularly preferably (A) /
(B) = Present in a ratio of 35/65 to 62/35. When the molar ratio of the repeating unit (A) exceeds 80%, the coefficient of linear expansion of the polyimide copolymer film becomes higher than the coefficient of linear expansion of metal, and the mechanical strength may be significantly reduced. On the other hand, when the molar ratio of the repeating unit (B) exceeds 75%, the linear expansion coefficient becomes lower than the linear expansion coefficient of metal, and the film becomes very brittle, and the film has low water absorption. May not be obtained. The above polyimide copolymer is a high molecular weight polymer and has a viscosity of 0.5 g / 100 m as a polyamic acid.
When measured in 1DMF, the logarithmic viscosity at a measurement temperature of 30 ° C. is preferably 0.5 to 5.

The polyimide copolymer of the present invention is 4,4 '.
-Aromatic diamine containing bis (4-aminophenoxy) biphenyl and p-phenylenediamine as main components and pyromellitic dianhydride are polymerized to obtain a polyamic acid copolymer, and then the polyamic acid copolymer It can be obtained by dehydration ring closure of the combined product.

In this case, in the present invention, it is preferable to use only two kinds of diamines, 4,4'-bis (4-aminophenoxy) biphenyl and p-phenylenediamine, as the aromatic diamine component. Aromatic diamine compounds such as 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) Phenyl] sulfone, bis [4- (2-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, bis (3-methyl-4-aminophenyl) methane, bis (3-chloro-4-). Aminophenyl) methane,
3,3'-dimethoxy-4,4'-diaminobiphenyl, 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'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4 '
-Diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 4,
4'-diaminooctafluorobiphenyl, 2,4-diaminotoluene, metaphenylenediamine, 4,4'-
Diaminobenzanilide, 3,4'-diaminobenzanilide, 4,3'-diaminobenzanilide, 2,2-
Bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (3-hydroxy-4-aminophenyl) propane 2,2-bis (3-hydroxy-4-aminophenyl) hexafluoropropane, 9,9-bis (4-aminophenyl)-
Although 10-hydro-anthracene, orthotolidine sulfone and the like can be used in an amount within the range in which the object and effects of the present invention are achieved, the amount of these other aromatic diamine compounds used is based on the total amount of the aromatic diamine compounds. 10 mol% or less, preferably a small amount of 5 mol% or less is suitable.

Therefore, the polyamide copolymer of the present invention is
The structural unit of the diamine residue based on the other aromatic diamine compound is preferably 1 of the structural unit amount of all the diamine residues.
It can be contained in an amount of 0 mol% or less, more preferably 5 mol% or less.

In obtaining the polyimide copolymer of the present invention, first, the aromatic diamine compound and pyromellitic dianhydride are reacted to synthesize a polyamic acid. In this case, the aromatic diamine compound and pyromellitic acid are synthesized. It is preferable to use the dianhydride in an approximately equimolar amount.
In addition, pyromellitic dianhydride and 4,4′-bis (4-
Aminophenoxy) biphenyl and p-phenylenediamine may be charged at the same time to synthesize a polyamic acid, or acid dianhydride and these diamines may be reacted in respective containers and then the respective polyamic acid solutions may be mixed. Good. It is also possible to synthesize a polyamic acid in which one is in excess of the acid anhydride component and the other is in excess of the diamine component, and as a result, the acid dianhydride and the diamine are mixed in equimolar amounts.

The above reaction is preferably carried out in an organic solvent. Examples of the organic polar solvent include sulfoxide-based solvents such as dimethyl sulfoxide, formamide-based solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide, N, N-
Acetamide-based solvents such as diethylacetamide, pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- or p-
Phenol solvents such as cresol, xylenol, halogenated phenol and catechol, hexamethylphosphoramide, γ-butyrolactone and the like can be mentioned. These may be used singly or as a mixture of two or more kinds, and may also be used in combination with an aromatic hydrocarbon organic nonpolar solvent such as xylene and toluene. The amount of the organic polar solvent used is not particularly limited,
Use of aromatic diamine, tetracarboxylic dianhydride and organic polar solvent so 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 amount.

The reaction temperature is preferably 0 to 60 ° C.,
The reaction time is usually 0.5 to 24 hours.

The viscosity of the obtained polyamic acid is not particularly limited, but as described above, 0.5 g / 100 ml DM
The logarithmic viscosity when measured in F (dimethylformamide) at a measurement temperature of 30 ° C. is preferably 0.5 to 5, which serves as an index of the molecular weight of the polyimide copolymer.

The polyamic acid synthesized as described above is then converted into the polyimide copolymer of the present invention by subjecting it to dehydration ring closure. This dehydration ring closure can be performed thermally or chemically according to a conventional method.

Specifically, the thermal dehydration ring closure of the polyamic acid copolymer can be achieved by heating at 200 to 500 ° C. for 1 to 120 minutes.

When the polyamic acid copolymer obtained above is chemically dehydrated and cyclized, a dehydrating agent and a catalyst can be used. 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 and allylphosphonic acid dihalides. , Thionyl halide and the like, and these can be used alone or in combination of two or more.

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. Examples thereof include amines, and these can be used alone or in combination of two or more.

To obtain a film-shaped polyimide copolymer from the above polyamic acid copolymer, first, 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 make this film 50 to 1
After drying at 50 ° C., a self-supporting film of polyamic acid containing 10 to 30% of solvent is obtained. Then, this film is peeled off from the support, the ends are fixed, and then heated to about 200 to 250 ° C. Then, the solvent is removed, and dehydration imidization is performed at 300 to 500 ° C. to obtain a polyimide film having a thickness of 10 to 150 μm.

The polyimide copolymer thus obtained is excellent in mechanical properties, has a coefficient of linear expansion equivalent to that of a metal, and has a low water absorption property. Suitable for use as a film material for flexible printed wiring boards and the like.

[0025]

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.

[Example 1] A 500 ml flask was charged with N,
N-dimethylformamide (DMF) 376.5 g,
Charge 4,4′-bis (4-aminophenoxy) biphenyl (BAPB) 18.42 g (0.05 mol) and p-phenylenediamine (p-PDA) 5.41 g (0.05 mol), and add nitrogen gas. The diamine was completely dissolved by stirring while flowing. Next, 21.81 g (0.10 mol) of pyromellitic dianhydride was added at a temperature of 25 ° C. while suppressing heat generation, and stirring reaction was performed under nitrogen for 3 hours to obtain a polyamic acid solution with a polymer concentration of 10%. It was Spread the polyamic acid solution thinly on a glass plate with an applicator,
Dry in an oven at 110 ° C for 60 minutes and then peel off,
Fix on an iron frame, 200 ℃, 60 minutes, then 300 ℃, 6
Desolvation by imidization at 0 minutes gave a film having a thickness of about 25 μm.

[Examples 2 to 5] The same procedure as in Example 1 was carried out by changing the molar ratio of BAPB / p-PDA.

[Comparative Example 1] A diamine was used in the same manner as in Example 1 except that 4,4'-diaminodiphenyl ether (DDE) was used.

[Comparative Example 2] The same procedure as in Example 1 was carried out using BAPB as the diamine.

[Comparative Example 3] The same procedure as in Example 1 was carried out except that p-PDA was used as the diamine. The film was very brittle and its physical properties could not be measured.

Next, the mechanical properties, linear expansion coefficient, and water absorption of the obtained film were measured as follows. The results are shown in Table 1. Mechanical Properties (Elastic Modulus) Measured according to 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 The polyimide film was left at 90% RH for 24 hours and the weight difference before and after that was measured to determine the water absorption.

[0032]

[Table 1]

[0033]

The polyimide copolymer of the present invention is excellent in mechanical properties, has a coefficient of linear expansion equivalent to that of a metal (for example, copper), and has a low water absorption rate. Further, according to the production method of the present invention, such a polyimide copolymer can be easily and surely obtained.

Front page continuation (72) Inventor Atsushi Sugitani, Kamisu-cho, Kashima-gun, Ibaraki 1st Towada, Shin-Etsu Chemical Co., Ltd., Polymer Functional Materials Research Center (72) Inventor Kiyoshi Kai, Kamisu-cho, Kashima-gun, Ibaraki Towada No. 1 Shin-Etsu Chemical Co., Ltd., Polymer Functional Materials Research Center

Claims (3)

[Claims] 1. A polyimide copolymer containing a repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B) as main constituent units. [Chemical 1] 2. The molar ratio of the repeating unit (A) to the repeating unit (B) is (A) / (B) = 25 / 75-80.
The polyimide copolymer according to claim 1, which is / 20. 3. A polyamic acid copolymer obtained by polymerizing an aromatic diamine containing 4,4′-bis (4-aminophenoxy) biphenyl and p-phenylenediamine as main components and pyromellitic dianhydride. The method for producing a polyimide copolymer according to claim 1, wherein the polyamic acid copolymer is subjected to dehydration ring closure.