JPH0725906B2 - Polyimide composite sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can be suitably used as a copper clad wiring board for producing printed wiring boards used in the electronics and electrical industries, and other types of metal materials. Aromatic polyimide film useful for producing a polyimide composite sheet (including tape etc.) composed of an aromatic polyimide film layer and a metal film layer that can be used as other electronic materials such as a magnetic tape. The present invention relates to a polyimide composite sheet including an aromatic polyimide film layer formed from a solution composition of an aromatic polyamic acid used as a dope solution for forming a layer and a metal film layer.

[0002]

2. Description of the Related Art Conventionally, a polyimide composite material (composite sheet) composed of an aromatic polyimide film layer and a metal material layer, and a method for producing the same have been described in, for example, Japanese Patent Publication No. 57-361.
35, Japanese Patent Publication No. 57-41491, Japanese Patent Publication No. 5
9-18221, JP-A-55-7805,
JP-A-56-118204 and JP-A-57-
It was known to be described or suggested in Japanese Patent No. 181857.

[Problems to be Solved by the Invention]

However, in the polyimide composite sheet composed of these known polyimide film layers and metal materials, the aromatic polyimide forming the aromatic polyimide film layer has a considerably large coefficient of thermal expansion with respect to the metal film layer. To have
When the polyimide film and the metal film layer are integrally laminated under heating to produce a composite sheet, and when the obtained composite sheet is subjected to thermal history during subsequent processing or use, There is a drawback that the composite sheet is curled, or because the aromatic polyimide film does not have sufficient physical properties such as mechanical strength, heat resistance (solder heat resistance), and flexibility. In addition, there was a drawback that the composite sheet could not be industrially used as an electric / electronic material.

[0004]

[Means for Solving the Problems] The inventors of the present invention have proposed an aromatic polyimide film capable of producing an excellent polyimide composite sheet without the drawbacks of known polyimide composite sheets, and an aromatic polyamic acid that is a precursor of aromatic polyimide. As a result of diligent research on a solution composition, etc., from a specific aromatic tetracarboxylic acid component consisting of biphenyltetracarboxylic acids and pyromellitic acid and a specific aromatic diamine component consisting of phenylenediamines and diaminodiphenyl ethers, Using a solution composition of an aromatic polyamic acid obtained by polymerizing both components in approximately equimolar amounts,
It was found that the formed aromatic polyimide film is bonded to the metal film layer to form an excellent composite sheet without the above-mentioned defects, and the present invention has been completed.

That is, the present invention relates to an aromatic tetracarboxylic acid component comprising 15 to 85 mol% of biphenyltetracarboxylic acid and 15 to 85 mol% of pyromellitic acid, based on the wholly aromatic tetracarboxylic acid component. Obtained by polymerizing substantially all of the aromatic diamine component consisting of 30 to 100 mol% of phenylenediamines and 0 to 70 mol% of diaminodiphenyl ethers with respect to the wholly aromatic diamine component. A solution composition of the aromatic polyamic acid thus obtained is cast on a metal thin film to form a film, and the film is dried, and an aromatic polyimide film layer formed by imidizing the polyamic acid at a high temperature. The present invention relates to a polyimide film composite sheet including a metal film layer.

From the solution composition of the above-mentioned aromatic polyamic acid, an aromatic polyimide film can be easily produced by a solution casting method or the like, and the aromatic polyimide film obtained from the solution composition is The coefficient of thermal expansion is close to the coefficient of thermal expansion of a general metal film and has a relatively small value. Furthermore, since the aromatic polyimide film has strong physical properties and flexibility, A composite sheet consisting of an aromatic polyimide film layer formed from a solution composition and a metal film layer is produced even while undergoing various thermal histories,
It does not curl.

Aromatic polyimide films (including films, sheets, etc.) produced from the above solution compositions have a relatively high second-order transition temperature, so that the composite sheet can be used at high temperatures, such as in soldering operations. Even if it receives a heat history (up to 300 ° C.), no problem occurs and the heat resistance is excellent.

The aromatic pomic acid used in the present invention is 15 to 8 with respect to the total tetracarboxylic acid component.
5 mol%, preferably 20-85 mol% of biphenyltetracarboxylic acids and 15-85 mol%, preferably 1
Aromatic tetracarboxylic acid component consisting of 5 to 80 mol% of pyromellitic acid, and 30 with respect to all diamine components
~ 100 mol%, preferably 40-95 mol% phenylenediamines, and 0-70 mol%, preferably 5-6.
It is a high-molecular-weight aromatic polyamic acid obtained by polymerizing an aromatic diamine component consisting of 0 mol% of diaminodiphenyl ethers in substantially equimolar amounts.

In the above-mentioned aromatic tetracarboxylic acid component, if the amount of biphenyltetracarboxylic acids used is too low, the coefficient of thermal expansion of the aromatic polyimide film formed from the resulting aromatic polyamic acid increases, and the tensile test is conducted. It is not suitable because the elongation at the break point decreases at the breaking point, and the flexibility of the composite sheet is lost, and if the proportion of biphenyltetracarboxylic acids used is too large, the second-order transition temperature of the aromatic polyimide film decreases. It is not suitable because it does.
In the aromatic tetracarboxylic acid component, the ratio of the total amount of biphenyltetracarboxylic acids and pyromellitic acid used is about 100 with respect to the total tetracarboxylic acid component.
It may be mol%, but about 5% of the total tetracarboxylic acid component
As long as the ratio is not more than mol%, each of the above-mentioned tetracarboxylic acids such as biphenyltetracarboxylic acids and pyromellitic acids may be partially replaced with another aromatic tetracarboxylic acid.

Further, in the present invention, an aromatic tetracarboxylic acid component comprising 25 to 85 mol% of biphenyltetracarboxylic acid and 15 to 75 mol% of pyromellitic acid is used as the aromatic tetracarboxylic acid component. Is most suitable from the viewpoint of the performance of the obtained aromatic polyimide film.

Further, in the aromatic diamine component, when the usage ratio of phenylenediamines decreases and the usage ratio of diaminodiphenyl ethers increases too much, when obtained, an aromatic polyimide film formed from an aromatic polyamic acid is formed. It is not suitable because the coefficient of thermal expansion increases, the elastic modulus and the second-order transition temperature decrease, and the waist strength and heat resistance are impaired, and when the usage ratio of phenylenediamines approaches 100 mol%, When the physical properties such as the elongation of the aromatic polyimide film are lowered, such polyimide film may be broken by a sudden tension or impact, or the stiffness may be too strong and the flexibility may be lost. There is. In the aromatic diamine component, the ratio of the total amount of phenylenediamines and diaminodiphenyl ethers used is about 10 with respect to all the diamine components.
It may be 0 mol%, but about 5 mol% of all diamine components
Each of the above diamines may be partially replaced with another aromatic diamine as long as the ratio is as follows. further,
In the present invention, in the aromatic diamine component, 55 to 9
0 mol% phenylenediamines, 10-45 mol%
It is most suitable from the viewpoint of the performance of the obtained aromatic polyimide film that the aromatic diamine component composed of the above diaminodiphenyl ethers is used.

In the present invention, the biphenyltetracarboxylic acids include 2,3,3 ', 4'-biphenyltetracarboxylic acid or its dianhydride, 3,3', 4.
Preferable examples thereof include 4'-biphenyltetracarboxylic acid or a dianhydride thereof, or an esterified product of the acid with a lower alcohol. Pyromellitic acid includes a dianhydride thereof or a lower alcohol of the acid. Preferable examples include esterified products. In addition,
As other tetracarboxylic acids that can be used by partially replacing the aromatic tetracarboxylic acids,
3,3 ′, 4,4′-benzophenone tetracarboxylic acid or its dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride The thing etc. can be mentioned suitably.

In the present invention, examples of phenylenediamines include 1,4-diaminobenzene (paraphenylenediamine), 1,3-diaminobenzene and 1,2-diaminobenzene, and examples of diaminodiphenyl ethers include , 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether,
3,4'-diaminodiphenyl ether etc. can be mentioned. Other diamine components that can be used by partially replacing the aromatic diamines mentioned above include 4,4′-diaminodiphenylmethane and 3,3′-
Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,
4'-diaminodiphenyl sulfone, ortho-thoridine, 3,5-diaminobenzoic acid and the like can be mentioned.

The aromatic polyamic acid has a high molecular weight of about 0.1 to 5, especially about 0.2 to 3, logarithmic viscosity (30 ° C., 0.5 g / 100 ml of N-methyl-2-pyrrolidone). A polymer, which is a polymer mainly having an amide-acid bond as a main chain bond of the polymer and soluble in an organic polar solvent, and by imidizing the polyamic acid by heating or the like, only an imide bond is formed. The heat-resistant aromatic polyimide substantially can be used.

The aromatic polyamic acid used in the present invention comprises the above-mentioned aromatic tetracarboxylic acid component and aromatic diamine component in substantially equimolar amounts, preferably at a polymerization temperature of 100 ° C. or less, particularly preferably at a temperature of 100 ° C. or less. Is produced at a polymerization temperature of 80 ° C. or lower in an organic polar solvent for about 0.2 to 60 hours so as to obtain a high molecular weight.

In the above-mentioned production method, it is common to use the polymer components consisting of the tetracarboxylic acid component and the diamine component in equimolar amounts at the same time, and polymerize them continuously or batchwise. It is also possible to carry out polymerization by using the monomer components not in equimolar amounts but by adding them at different use ratios at different times so that both components are finally equimolar. In the above production method, the tetracarboxylic acid component and the diamine component do not need to be used so that the ratio of the total amount used is completely equimolar, and for adjustment of the molecular weight or the like, one of the components is used. It may be used in excess at a ratio of about 3 mol% or less, particularly 1 mol% or less.

In the above-mentioned production method, the organic polar solvent preferably has a boiling point of 300 ° C. or less at atmospheric pressure, particularly 250 ° C. or less, and N-methyl-2-pyrrolidone, dimethylsulfoxide, N, N-dimethyl. Acetamide, N,
Preferable examples include N-dimethylformamide, N, N-diethylacetamide, N, N-diethylformamide and methylsulfone. These organic polar solvents can be used by mixing with other organic solvents such as benzene, toluene, benzonitrile, xylene, solvent naphtha and dioxane.

The solution composition of the aromatic polyamic acid used in the present invention is the same as the specific aromatic polyamic acid produced as described above, except that the organic polar solvent (the same organic polarity as that used for the polymerization solvent is used). Solvent), 5 to 40% by weight, preferably 5 to 35% by weight, particularly preferably 7 to 3%
It is a solution composition in which it is dissolved in a proportion of 0% by weight.
The above-mentioned solution composition can be prepared by isolating the aromatic polyamic acid produced as described above from the polymerization reaction solution, and then adding and dissolving the polymer in an organic polar solvent to prepare the solution composition. In the method for producing an aromatic polyamic acid, the same solvent used in the solution composition of the present invention is used as a polymerization solvent to polymerize each of the above-mentioned monomer components to once isolate the aromatic polyamic acid. Alternatively, the solution composition may be directly prepared.

The solution composition has a rotational viscosity measured at 30 ° C. of about 0.1 to 50000 poise, especially 0.5 to 3
From the viewpoint of workability of handling this solution composition, it is preferably about 0000 poise, more preferably about 1 to 20000 poise.

In the present invention, the aromatic polyimide film layer is, as a specific example, a solution composition of the above-mentioned aromatic polyamic acid, which is the surface of a roll or belt to which a metal thin film, for example, a metal foil or a metal thin film tape is being supplied. Cast at room temperature or under heating to about 10 to 2000 μm,
Particularly, a film-like body of the solution composition having a uniform thickness of about 30 to 1000 μm is continuously formed, and the film-like body on the support is subjected to atmospheric pressure or pressure at about 50 to 500 ° C. It is gradually heated and dried within a temperature range to evaporate and remove the solvent from the film body to form a solidified film, and the polyamic acid (solidified film) has an imidization rate of 90% or more, particularly 95% or more. To be imidized under high temperature heating (imide cyclization)
Then, it is manufactured by a method of forming an aromatic polyimide film having a film thickness of 0.5 to 300 μm, particularly 1 to 200 μm.

The aromatic polyimide film is 100 to 3
The average coefficient of thermal expansion at 00 ° C. is relatively low, and general copper or its alloys, iron, nickel, cobalt, chromium, etc., or alloys thereof (for example, steel, nickel steel,
Since the coefficient of thermal expansion is similar to that of metals such as chrome steel and magnetic materials), the polyimide composite sheet consisting of those metal film layers and the aromatic polyimide film layer of the present invention is heated during the manufacturing process. As a result, curling does not occur, and it can be suitably used for applications such as flexible printed wiring boards (copper clad boards).

The above-mentioned aromatic polyimide film has tensile strength (about 20 kg / mm ² or more, especially 25 kg / mm ² or more), elongation (about 20% or more), elastic modulus (about 300).
Mechanical properties such as ~ 900 kg / mm ² ), second-order transition temperature (about 300 ° C or higher) and thermal decomposition start temperature (about 40)
Since it is excellent in thermal properties such as high temperature (0 ° C. or higher), it can be practically used for the above-mentioned applications.

In the present invention, the aromatic polyimide film layer has, for example, (a) a coefficient of thermal expansion of (a) if the above-mentioned monomer components are used in an appropriately selected ratio in the preparation and film formation of the above-mentioned aromatic polyamic acid. 1.0 x 10 ^-5
To 3.0 × 10 ⁻⁵ cm / cm / ° C., especially 1.2
× 10 ^{−5 to} 2.8 × 10 ⁻⁵ cm / cm / ° C.
And (b) the second-order transition temperature is 300 ° C or higher, particularly 305 ° C or higher, more preferably 310 ° C or higher, and (c) the elastic modulus is 300 to 900 kg / mm ² , particularly 350 to 700 kg /. mm ² and (d)
An elongation percentage of 20% or more, particularly about 40 to 120%, can be produced, and an aromatic polyimide having such properties has the mechanical strength and thermal properties required for the above-mentioned applications. Is preferred.

The polyimide composite sheet comprising the aromatic polyimide film layer and the metal film layer according to the present invention is one in which the aromatic polyimide film layer has various mechanical and thermal properties as described above. In particular, it has a coefficient of thermal expansion close to that of a general metal film, and has a second-order transition temperature improved to a relatively high temperature side, and also has excellent electrical insulation. Therefore, it can be used as a protective coating film for a metal film layer for electric / electronic materials, a support film, and the like. Specifically, a flexible printed wiring copper clad substrate,
It can be suitably used as a supporting film layer of a magnetic tape or the like.

[0025]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. Example 1 In a cylindrical polymerization tank having an internal volume of 300 ml, 3,3 ', 4
4'-biphenyltetracarboxylic dianhydride 20.59
g (0.07 mol), pyromellitic dianhydride 6.54
g (0.07 mol), para-phenylenediamine 5.41
g (0.05 mol) and 4,4′-diaminodiphenyl ether 10.01 g (0.05 mol), and further N-
198.0 g of methyl-2-pyrrolidone was added. This mixture was stirred at a reaction temperature of 50 ° C. under normal pressure for 44 hours to carry out a polymerization reaction, and an inherent viscosity (30 ° C., 0.5 g / 100 m).
1N-methyl-2-pyrrolidone) is 2.04, the rotational viscosity (30 ° C.) is about 1300 poise, and the imidization ratio is about 20% or less.
A reaction liquid containing 0% by weight was obtained. The reaction solution had good storage stability for about 1 month or longer.

Using a solution composition of the aromatic polyamic acid obtained as described above, on a copper foil (coefficient of thermal expansion; 1.66 × 10 ⁻⁵ cm / cm / ° C.) having a thickness of about 30 μm To form a liquid film (thickness: about 150 μm) of the solution composition having a uniform thickness, and the liquid film is about 60 to 2
Drying and solidifying while heating in the temperature range up to 00 ° C,
Heat it to 350 ℃ and heat it to a thickness of 3
A copper clad substrate consisting of a 0 μm aromatic polyimide film layer and a 30 μm thick copper film layer was formed. This copper-clad substrate had no curl within a radius of curvature of 50 cm and had appropriate flexibility, and could be suitably used as a flexible printed wiring copper-clad substrate.

From the copper clad substrate formed as described above, the copper film layer was dissolved and removed with an etching solution to obtain an aromatic polyimide film (film). Various physical properties of this aromatic polyimide film were measured, and the results are shown.
This polyimide film has a tensile strength of 36.1 kg / mm ² and an elongation of 60% in a tensile test.
And the elastic modulus is 507 kg / mm ² , and the coefficient of linear expansion is 1.9 × 10 ⁻⁵ cm / c in the measurement of the coefficient of thermal expansion in the temperature range of 100 to 300 ° C.
m / ° C, TMA tensile method (material width: 5 mm,
The second-order transition temperature (Tg) was measured at 2 g and a heating rate of 10 ° C./min, and the second-order transition temperature was 360 ° C., and the thermal decomposition initiation temperature was measured at about 440 ° C.

Examples 2 to 18 Solution compositions of aromatic polyamic acid were prepared in the same manner as in Example 1 except that the ratio of the monomer components used for producing the aromatic polyamic acid was as shown in Table 1. Was manufactured. A copper clad substrate was manufactured in the same manner as in Example 1 except that the solution composition thus obtained was used. Further, an aromatic polyimide film was formed in the same manner as in Example 1 except that the above copper clad substrate was used, and the physical properties of the film were measured. Table 1 shows a part of the result of the measurement.

[0029]

[Table 1]

Comparative Examples 1 to 15 Aromatic polyamic acid solution compositions were prepared in the same manner as in Example 1 except that the proportions of the monomer components used for producing the aromatic polyamic acid were as shown in Table 2. Was manufactured. A copper clad substrate was manufactured in the same manner as in Example 1 except that the solution composition thus obtained was used. Further, an aromatic polyimide film was formed in the same manner as in Example 1 except that the above copper clad substrate was used, and the physical properties of the film were measured. Table 2 shows a part of the result of the measurement.

[0031]

[Table 2]

In the copper clad substrate of each of the above-described embodiments, since the difference in the coefficient of thermal expansion between the aromatic polyimide film layer and the copper film layer is quite small, a flat composite sheet with substantially no curl having a radius of curvature of 50 cm or less. However, the copper clad substrate of each of the comparative examples described above had a curl with a radius of curvature of 10 cm or less because the difference in the coefficient of thermal expansion from the aromatic polyimide film layer was considerably large. In Tables 1 and 2, P
PD is paraphenylenediamine, DADE is 4,4'-
Diaminodiphenyl ether, BPDA is 3,3 ',
4,4'-biphenyltetracarboxylic dianhydride, PM
DA means pyromellitic dianhydride.

[0033]

The polyimide composite sheet of the present invention comprises a specific aromatic tetracarboxylic acid component composed of biphenyltetracarboxylic acids and pyromellitic acid, and a specific aromatic diamine component composed of phenylenediamines and diaminodiphenyl ethers. From the above, using a solution composition of an aromatic polyamic acid obtained by polymerizing both components in approximately equimolar amounts, an aromatic polyimide film formed by casting is formed by bonding with a metal film layer. is there. Moreover, the aromatic polyimide film obtained from the solution composition has a relatively small coefficient of thermal expansion close to that of a general metal film and a relatively high second-order transition temperature. The composite sheet has excellent heat resistance without any problem even when subjected to a high temperature (up to about 300 ° C.) heat history such as a soldering operation. Further, since the aromatic polyimide film has a strong physical property and flexibility, it is a composite sheet comprising an aromatic polyimide film layer and a metal film layer formed by casting from the solution composition of the present invention. However, even if it is manufactured while undergoing various thermal histories, it does not curl.

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Claims (2)

[Claims] 1. A wholly aromatic tetracarboxylic acid component,
15-85 mol% of biphenyl tetracarboxylic acids and 1
An aromatic tetracarboxylic acid component composed of 5 to 85 mol% of pyromellitic acid, and 30 to 100 mol% of phenylenediamines and 0 to 100% of the total aromatic diamine component.
Aromatic polyamic acid obtained by polymerizing an aromatic diamine component composed of 70 mol% of diaminodiphenyl ethers in a substantially equimolar amount is dissolved in an organic polar solvent in an amount of 5 to 40% by weight. Aromatic polyimide film layer and metal film formed by casting a solution composition of aromatic polyamic acid on a metal thin film to form a film, drying the film, and imidizing the polyamic acid at high temperature Polyimide composite sheet consisting of layers. 2. An aromatic polyimide film having a second-order transition temperature of 300.degree. C. or higher and 1.0.times.10.sup.- ^{5 to} 3.0.times.10.sup.- ⁵ cm.
/ Cm / ° C thermal expansion coefficient, 300-900 kg / mm ²
The polyimide composite sheet according to claim 1, which has an elastic modulus of 20% and an elongation of 20% or more.