JPH0570591A - Polyamic acid copolymer and polyimide film formed from the same - Google Patents

Abstract

PURPOSE:To provide a polyimide film having a linear expansion coefficient close to those of metals and glass and improved in modulus of elasticity. CONSTITUTION:5-40mol.% 3,3', 4,4'-benzophenonetetracarboxylic acid dianhydride and 10-35mol% at least one member selected from among pyromellitic acid dianhydride and its derivs. are reacted with 10-45mol% linear diamine and 5-40mol% flexible diamine with the total amt. of the acid anhydride compds. being substantially the same as the total amt. of the diamine compds. to obtain a polyamic acid copolymer, which is then formed into a polyimide film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide film having excellent heat resistance, high elasticity, and a coefficient of thermal expansion close to that of metal or glass, and a polyamic acid copolymer which is a precursor thereof. is there.

[0002]

2. Description of the Related Art Conventionally, a polyimide resin has excellent heat resistance and electrical insulation properties, and has been widely used as an industrial material including electric equipment. The polyimide resin is
As described above, it has various excellent properties as compared with other polymers, but with the progress of technology, the required properties required for polyimide resins will also become higher, and it is desired to have various performances depending on the application. There is.

In particular, in recent years, it has been increasingly used in electric and electronic materials for which the tendency of miniaturization and refinement has become remarkable, so that the dimensional stability of the polyimide used is strongly desired. There is. Among them, film applications include many processes in which stress is applied and processes in which temperature is changed, and therefore, it is desired that dimensional changes due to stress and temperature changes are small. In order to reduce the dimensional change due to stress, it is effective that the film has a high elastic modulus, and in order to reduce the dimensional change due to temperature change, it is effective that the film has a small linear expansion coefficient. However, polyimide is mainly used for films such as flexible printed circuit board, TAB base film, and copper wire coating, and these are all composites with metal such as copper or glass. Therefore, it is not preferable for practical use that the coefficient of linear expansion is extremely smaller than that of metal such as copper or glass.

It is conventionally known that it is effective to use a monomer having high linearity in order to obtain a high elastic modulus. For example, a polyimide having very high elasticity can be synthesized by using only a rigid straight chain such as pyromellitic anhydride and paraphenylenediamine. However, such a structure is very brittle, and the coefficient of linear expansion becomes too small, which is not preferable in practice.

[0005]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a polyamic acid copolymer having excellent heat resistance, high elasticity, and excellent properties such as an appropriate coefficient of linear expansion, and a polyimide film comprising the same. To do.

[0006]

[Means for Solving the Problems] In order to solve the above problems, as a result of intensive studies, the present inventors have found a polyamic acid copolymer and a polyimide film comprising the same, and completed the present invention. That is, the first aspect of the present invention is 3,
15'-40 mol% of 3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 10-35 mol of at least one selected from pyromellitic dianhydride and its derivative
%, Linear diamine 10 to 45 mol%, and flexible diamine 5 to 40 mol% are reacted so that the molar amounts of the total acid anhydride compound and the total diamine compound are approximately equal to each other. A second aspect of the present invention is a polyimide film obtained by molding the above polyamic acid copolymer into a film and then dehydrating and ring-closing.

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

[0008]

[Chemical 1]

(However, X is F, C1, Br, CH ₃ ,
CH ₃ O and CF ₃ are shown. ) And the like, and these can be used alone or in admixture of two or more. On the other hand, the flexible diamine means, in the main chain, a diamine having a structure containing a flexible group such as an ether bond or a carbonyl group, or a meta-position, or an aromatic diamine containing a bond at the ortho-position, for example,

[0010]

[Chemical 2]

[0011]

[Chemical 3]

Examples of diamines such as ## STR1 ## can be used alone or in admixture of two or more.

The polyamic acid copolymer solution of the present invention comprises
The acid anhydride and the diamine component are obtained by polymerizing in an organic polar solvent using substantially equimolar amounts.
15-40 mol% of 3 ', 4,4'-benzophenone tetracarboxylic dianhydride, more preferably 25-35 mol
%, At least one selected from pyromellitic dianhydride and its derivative is used in an amount of 10 to 35 mol%, more preferably 15 to 25 mol%. If the ratio of pyromellitic dianhydride is higher than this, the polyimide film becomes brittle and the linear expansion coefficient becomes too low. Also, 3,
If the ratio of 3 ', 4,4' benzophenone tetracarboxylic dianhydride is larger than this, the elastic modulus of the film becomes low.

The diamine compound is a linear diamine of 10 to 45 mol%, more preferably 20 to 40 m.
ol%, flexible diamine 5 to 40 mol%, more preferably 10 to 30 mol%. If the ratio of the linear diamine is larger than this, the film becomes brittle, and if the ratio of the flexible diamine is larger than this, the elastic modulus becomes low,
The coefficient of linear expansion becomes too large. It is more preferable to use para-phenylenediamine as the linear diamine. Paraphenylenediamine does not have an aliphatic substituent, and therefore has excellent heat resistance. As the flexible diamine, it is more preferable to use 4,4'diaminodiphenyl ether. Among the flexible diamines, 4,4'diaminodiphenyl ether has relatively high heat resistance and excellent chemical stability.

Examples of the organic polar solvent used in the reaction for producing the polyamic acid copolymer include sulfoxide type solvents such as dimethyl sulfoxide and diethyl sulfoxide; formamides such as N, N-dimethylformamide and N, N-diethylformamide. System solvent; acetamide system solvent such as N, N-dimethylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone,
Pyrrolidone-based solvents such as N-vinyl-2-pyrrolidone;
Phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, and catechol; or hexamethylphosphoramide, γ-butyrolactone, and the like can be used, and these are used alone or as a mixture. However, it is also possible to partially use an aromatic hydrocarbon such as xylene or toluene.

Specifically, the polyamic acid copolymer solution can be polymerized by the following procedure, for example. An organic polar solvent, a linear diamine and a flexible diamine are weighed out in a container, and the mixture is cooled and stirred. Substantially at least one tetracarboxylic dianhydride selected from pyromellitic dianhydride and pyromellitic dianhydride derivative and 3,3 ′, 4,4′benzophenone tetracarboxylic dianhydride Gradually add all acid anhydride components and all diamine components until equimolar. The polyamic acid copolymer is preferably contained in the organic polar solvent in an amount of 5 to 40% by weight, more preferably 10 to 3% by weight.
It is desirable that 0% by weight is dissolved from the viewpoint of handling.

In order to obtain the polyimide film of the present invention from this polyamic acid copolymer solution, either a thermal method of thermal dehydration or a chemical method using a dehydrating agent may be used. It is preferable because the resulting polyimide film has excellent mechanical properties such as elongation and tensile strength. Hereinafter, an example of a method for producing a polyimide film will be described. The above polyamic acid polymer or the solution thereof is used in a stoichiometric amount of a dehydrating agent and a catalytic amount of a third
A solution to which a primary amine has been added is cast or applied onto a drum or an endless belt to form a film, and 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. . Then, this is peeled off from the support and the end is fixed. Then, the polyimide film of the present invention is obtained by gradually heating to about 100 to 500 ° C. for imidization, cooling and then removing from the drum or endless belt. Examples of the dehydrating agent 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. These dehydrating agents and catalysts may be used alone or in combination of two or more.

[0018]

[Function] Conventionally, it has been used as a raw material for a polyimide having a low elastic modulus and being soluble or thermoplastic.
By reacting 3 ', 4,4' benzophenone tetracarboxylic dianhydride with pyromellitic dianhydride / flexible diamine / linear diamine in a specific ratio, the planarity and linearity of the benzophenone structure can be improved. A possible conformation is developed, and as a result, a film having a high elastic modulus can be obtained while maintaining the linear expansion coefficient at a value close to that of metal or glass.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, ODA is 4,4'-diaminodiphenyl ether, p-PDA is paraphenylenediamine, T
PE-Q is 1,4-bis (4-aminophenoxy) benzene, PMDA is pyromellitic dianhydride, BTDA is benzophenonetetracarboxylic dianhydride, and DMF is dimethylformamide.

Example 1 1 kg of DMF and pp were placed in a 2-liter separable flask.
DA was 37.8 g (37.5 mol%) and ODA was 23.3.
g (12.5 mol%) was taken, mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 33.8 g (16.7 mol) of PMDA
%) And 100.0 g (33.3 mol%) of BTDA are gradually added in the form of powder to give a viscosity of 2500 po.
When it became ise, the addition was stopped, and then the mixture was cooled and stirred for about 30 minutes to obtain a DMF solution of polyamic acid. Acetic anhydride and isoquinoline were added to the polyamic acid solution, mixed and cast on a glass plate, dried at about 100 ° C for about 5 minutes, peeled off the polyamic acid coating film from the glass plate, and fixed on a support frame. , Then at 200 ℃ for about 1 minute, about 3
It was heated at 00 ° C. for about 1 minute and at 450 ° C. for about 2 minutes, and dehydrated and ring-closed dried to obtain a polyimide film of about 25 microns. The physical properties of the obtained polyimide film are shown in Table 1.

Example 2 1 kg of DMF and pp were placed in a 2 liter separable flask.
DA 37.8 g (37.5 mol%) and TPE-Q 3
4.0 g (12.5 mol%) was taken, mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, 33.8 g (16.7 g) of PMDA
(mol%) and BTDA (100.0 g (33.3 mol%)) are added gradually in powder form to a viscosity of 250.
The addition was stopped when it reached 0 poise, and then about 30
After cooling and stirring for a minute, a DMF solution of polyamic acid was obtained.
Acetic anhydride and isoquinoline were added to the polyamic acid solution, mixed and cast on a glass plate, dried at about 100 ° C for about 5 minutes, peeled off the polyamic acid coating film from the glass plate, and fixed on a support frame. Then, the mixture was heated at about 200 ° C. for about 1 minute, at about 300 ° C. for about 1 minute, and at about 450 ° C. for about 2 minutes for dehydration ring-closing drying to obtain a polyimide film of about 25 μm. The physical properties of the obtained polyimide film are shown in Table 1.

Example 3 1 kg of DMF and pp were placed in a 2-liter separable flask.
DA is 33.3 g (33.2 mol%) and ODA is 31.
2 g (16.8 mol%) was taken and mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, PMDA 42.2 g (20.8 m
ol%) and BTDA 87.4 g (29.2 mol%) near the total amount is gradually added in powder form and the viscosity is 2500 po.
When it became ise, the addition was stopped, and then the mixture was cooled and stirred for about 30 minutes to obtain a DMF solution of polyamic acid. Acetic anhydride and isoquinoline were added to the polyamic acid solution, mixed and cast on a glass plate, dried at about 100 ° C for about 5 minutes, peeled off the polyamic acid coating film from the glass plate, and fixed on a support frame. , Then at 200 ℃ for about 1 minute, about 3
It was heated at 00 ° C. for about 1 minute and at 450 ° C. for about 2 minutes, and dehydrated and ring-closed dried to obtain a polyimide film of about 25 microns. The physical properties of the obtained polyimide film are shown in Table 1.

Comparative Example 1 By the same method as in Example 1, a polyimide film was obtained using PMDA and ODA in equimolar amounts. The physical properties of the obtained polyimide film are shown in Table 1.

Comparative Example 2 1 kg of DMF and p-P were placed in a 2-liter separable flask.
DA is 37.8 g (37.5 mol%) and ODA is 23.
3 g (12.5 mol%) was taken and mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, BTDA 150.0 g (50.0
(mol%) is gradually added in powder form, and the viscosity is 25
When the poise reached 00poise, the addition was stopped, and then about 3
The mixture was cooled and stirred for 0 minutes to obtain a DMF solution of polyamic acid. Acetic anhydride and isoquinoline were added to the polyamic acid solution, mixed and cast on a glass plate, dried at about 100 ° C for about 5 minutes, peeled off the polyamic acid coating film from the glass plate, and fixed on a support frame. Then, the mixture was heated at about 200 ° C. for about 1 minute, at about 300 ° C. for about 1 minute, and at about 450 ° C. for about 2 minutes for dehydration ring-closing drying to obtain a polyimide film of about 25 μm. Table 1 shows the physical properties of the obtained polyimide film.
It was shown to.

Comparative Example 3 1 kg of DMF and pp were placed in a 2 liter separable flask.
DA 16.7g (25.0 mol%) and ODA 31.
3 g (25.0 mol%) was taken, mixed well at room temperature until the diamino compound was completely dissolved, and then stirred while cooling with ice. Next, PMDA 67.7 g (50.0 m
ol%) is gradually added in powder form and the viscosity is 250
When it reached 0 poise, the addition was stopped, and then about 30
After cooling and stirring for a minute, a DMF solution of polyamic acid was obtained.
Acetic anhydride and isoquinoline were added to the polyamic acid solution, mixed and cast on a glass plate, dried at about 100 ° C for about 5 minutes, peeled off the polyamic acid coating film from the glass plate, and fixed on a support frame. Then, the mixture was heated at about 200 ° C. for about 1 minute, at about 300 ° C. for about 1 minute, and at about 450 ° C. for about 2 minutes for dehydration ring-closing drying to obtain a polyimide film of about 25 μm. The physical properties of the obtained polyimide film are shown in Table 1.

[0026]

[Table 1]

[0027]

As described above, according to the present invention, 3,3 ',
4,4 ′ benzophenone tetracarboxylic dianhydride,
By using pyromellitic dianhydride or a derivative thereof, and a linear diamine and a flexible diamine in a specific ratio, the coefficient of linear expansion is not extremely different from that of metal or glass, and the specific elastic modulus is It is intended to provide a high polyimide film, and to provide an optimal material for electronic / electrical applications used in combination with metal or glass.

Claims (3)

[Claims] 1. At least 1 selected from 3,3 ', 4,4' benzophenone tetracarboxylic dianhydride 15 to 40 mol%, pyromellitic dianhydride and derivatives thereof.
Seed 10-35 mol%, linear diamine 10-45 mol
%, A polyamic acid copolymer obtained by reacting 5 to 40 mol% of a flexible diamine so that the molar amounts of the total acid anhydride compound and the total diamine compound are approximately equal. 2. The polyamic acid copolymer according to claim 1, wherein the linear diamine is paraphenylenediamine and the flexible diamine is 4,4′diaminodiphenyl ether. 3. A polyimide film obtained by forming the polyamic acid copolymer according to claim 1 or 2 into a film and then dehydrating and ring-closing.