JP3320524B2 - Polyimide film / metal foil laminate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel laminate of a polyimide film / metal foil laminate which does not contain an adhesive layer such as an epoxy resin, which has begun to spread in the electronics industry, and a method for producing the laminate. More specifically, the present invention relates to a method for producing a polyimide film and a metal foil laminate having excellent physical properties such as elongation and strength of the film and good dimensional stability.

[0002]

2. Description of the Related Art A large application of a polyimide film / metal foil laminate includes a printed circuit board, a sheet heating element and the like, and various laminates have been developed. The polyimide film for such purpose is required to have appropriate flexibility and rigidity, and the metal foil laminate is required to have high dimensional stability. In order to satisfy these demands, various kinds of polyamic acids are mixed, copolyimides are synthesized, and dry imidization is performed under specific conditions, but none of them is satisfactory.

That is, for example, Japanese Patent Application Laid-Open No. 58-1900
In 93, as shown in all the examples, after applying a varnish to a copper foil, drying at 80 ° C. for 2 hours, and then drying at a higher temperature, the characteristics of the polyimide / copper foil laminate (hereinafter abbreviated as FCL) were obtained. But there is a problem that the production time is long. Japanese Patent Application Laid-Open No. 59-162044 discloses 100-200.
Attempts have been made to improve the properties of the FCL by removing substantially all of the solvent at <RTIgt; JP-A-60-15
7286, in particular, in the examples, two kinds of amines, p-phenylenediamine and bisaminophenyl ether, are used to control the coefficient of thermal expansion, and the dimensional stability is satisfied, but the hand solderability is reduced. In addition, there is a problem that the elastic modulus is high and the flexibility is lacking. JP-A-63-8
In 4089, pyromellitic dianhydride was used as the acid anhydride.
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, copolyamic acid containing p-phenylenediamine and bisaminophenol as diamines as essential components and varnish of copolyamic acid are applied to copper foil and dried. The method is to continuously or stepwise increase the temperature to 100 to 300 ° C.
It has been proposed that the temperature is raised over 5 hours or more, and then the temperature is raised or maintained and heated to 300 to 350 ° C. over 0.5 hour or more. However, the FCL of 16 to 21 kg / mm ² is not always sufficient.

[0004]

The method of synthesizing and mixing two or more kinds of amic acids and imidizing them is excellent in the physical properties of the obtained polyimide film, but has a problem that the production method is complicated. . On the other hand, it is conceivable to synthesize a copolyamic acid from the beginning, but there is a problem that physical properties are not sufficient in a usual synthesis method. Further, the dry imidization is carried out at 150 ° C. or less and the residual solvent is 33
% Or less (Japanese Unexamined Patent Publication No. 1-245587), but there is a problem that the balance between physical properties and dimensional stability of the polyimide film is not always sufficient, and economical efficiency is not sufficient in terms of production speed. There was a problem that said.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of intensive studies on the composition and synthesis method of copolyamic acid and the method of dry imidization after being applied to a metal foil, and has excellent film physical properties and dimensional stability. In addition, a novel polyimide film / metal foil laminate excellent in productivity and a method for producing the same have been completed. That is, the present invention comprises at least two acid anhydrides of pyromellitic dianhydride 20-80 mol% and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 80-20 mol%, Polyamic acid obtained by reacting 50 to 80 mol% of p-phenylenediamine and 50 to 20 mol% of diamine represented by the following formula (Formula 1) and [Chemical Formula 3] in a solvent is used as a metal. A polyimide film characterized by being applied to a foil and then heated to be dried and imidized.
A metal foil laminate,

[0006]

Embedded image (Wherein, X represents a direct bond, a hydrocarbon group having 1 to 10 carbon atoms, a 6-fluorinated isopropylidene, a carbonyl group, a thio group or a sulfonyl group.) A method for producing the above polyimide film / metal foil laminate First, at least a portion of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added to a solution in which the amine was previously dissolved, and reacted, and then pyromellitic dianhydride was added. A method for producing a polyimide film-metal foil laminate, characterized in that the reacted polyamic acid is applied to a metal foil, and a method for producing the polyimide film-metal foil laminate, wherein the polyimide film -In the production process of the metal foil laminate, the temperature of the hot air used for drying and imidizing the polyamic acid is 220 ° C. or less, the wind speed is 3 m / min or more, and the solvent concentration is 1% or less. The residual solvents in the film to be formed 50
% Or less, and the residual solvent is further reduced to 0.5% or less at a temperature of 300 ° C. or more, and a solution in which the amine is previously dissolved. First, at least some 3,3 ', 4,4'-
After adding and reacting biphenyltetracarboxylic dianhydride, a method for producing a polyimide film / metal foil laminate in which a polyamic acid reacted with pyromellitic dianhydride is applied to a metal foil, As p
-Phenylenediamine 50-80 mol%, the following formula (Formula 1),
A polyimide film / metal foil laminate using 30 to 5 mol% of a diamine represented by [Chemical Formula 4] and 20 to 15 mol% of bisaminophenyl ether,

[0007]

Embedded image (Wherein, X represents a direct bond, a hydrocarbon residue having 1 to 10 carbon atoms, a hexafluorinated isopropylidene, a carbonyl group, a thio group or a sulfonyl group.) For producing the above polyimide film / metal foil laminate. In a method, to a solution in which the amine was previously dissolved, at least a portion of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride was added and reacted, and then pyromellitic dianhydride was obtained. A method for producing a polyimide film / metal foil laminate, characterized by applying a polyamic acid reacted with a metal foil, and a method for producing the polyimide film / metal foil laminate, wherein the polyimide In the production process of the film / metal foil laminate, it is produced by setting the temperature of hot air used for drying and imidizing polyamic acid to 220 ° C. or less, the wind speed to 3 m / min or more, and the solvent concentration to 1% or less. The residual solvent of the film to be 50% or less, and then the residual solvent is reduced to 0.5% or less at a temperature of 300 ° C. or more. At least a portion of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride was added to the solution in which the amine was dissolved and reacted, and then the polyamic acid reacted with pyromellitic dianhydride was treated with metal. This is a method for producing a polyimide film / metal foil laminate to be applied to a foil.

In the present invention, in order to make the physical properties of the film have appropriate rigidity and appropriate flexibility, at least 20 to 80 mol% of pyromellitic dianhydride is used as an acid anhydride. It is preferred to use 80% to 20% by mole of two acid anhydrides of 2,3 ', 4,4'-biphenyltetracarboxylic dianhydride. As the diamine component, p-phenylenediamine 50 to 80 mol% and the following general formula (formula 1):
It is preferable to use two amines of 50 to 20 mol% of a diamine represented by the following formula (hereinafter abbreviated as tetranuclear). By copolymerizing such tetranuclear bodies, as shown in Examples below, the resulting polyimide film exhibits high values of the breaking strength and the elongation, and the desired toughness of the film as FCL can be obtained. .

[0009]

Embedded image In the present invention, as amine components, diaminobiphenyl, bisaminophenyl ether, bisaminophenylsulfone, bisaminophenylsulfide, bisaminophenylsulfoxide, diaminobenzophenone, bisaminophenylmethane, bisaminophenylethane, bisaminophenyl It is preferable to use two benzene rings (hereinafter abbreviated as binuclear) such as aminophenylpropane and bisaminophenylhexafluoropropane in combination, and it is more preferable to use bisaminophenyl ether in particular.

In the present invention, the molar ratio of pyromellitic dianhydride to 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride is preferably about 20:80 to 80:20. If the value is out of this range, the balance of physical properties is not preferable. As the acid anhydride, it is essential to use the above two kinds, but other acid anhydrides may be mixed and used for increasing flexibility. The mixing amount is preferably about 30 mol% or less, particularly about 15 mol% or less of the whole acid anhydride. Examples of other acid anhydrides include:
Aliphatic tetracarboxylic dianhydrides such as ethylene tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, 1,1-bis (2,3-dicarboxyphenyl) Ethane dianhydride, 1,1-
Bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,
2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,
3,3-hexafluoropropane dianhydride, 2,2-bis (3,4
-Dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,2 ′, 3, 3'-benzophenonetetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3- Dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (2,3-dicarboxyphenyl)
Sulfone dianhydride, 4,4'- (p-phenylenedioxy)
Diphthalic dianhydride, 4,4 '-(m-phenylenedioxy)
Diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic acid Dianhydride,
3,4,9,10-perylenetetracarboxylic dianhydride, 1,2,7,
8-phenanthrenetetracarboxylic dianhydride and the like.

In the present invention, the phenylenediamine, the binuclear and the tetranuclear are in a quantitative ratio of at least 50 to 80 mol% for the phenylenediamine, 20 to 15 mol% for the binuclear,
Preferably, the tetranuclear is 30-5 mol%. As a tetranuclear substance, specifically, X is directly connected, the middle is a biphenyl group,
Methylbiphenyl group, 3,3'-dimethylbiphenyl group, 3,
5-dimethylbiphenyl group, 3,3 ', 5,5'-tetramethylbiphenyl group, 3,3'-dichlorobiphenyl group, 3,5-dichlorobiphenyl group, 3,3', 5,5'-tetrachloro Biphenyl group,
3,3′-dibromobiphenyl group, 3,5-dibromobiphenyl group, 3,3 ′, 5,5′-tetrabromobiphenyl group,
A benzophenone group in which X is a ketone, or a substituent thereof in the same manner as the above biphenyl group, or a diphenyl sulfide group in which X is a sulfide or 3,5-
Dimethoxyphenylphenyl sulfide group, bis (3,5,
-Dimethoxyphenyl) sulfide group or diamine wherein di is a diphenyl sulfone group wherein X is a sulfone, and these can be used alone or as a mixture of two or more.

Solvents used for producing the polyamic acid are usually N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2. -Pyrrolidone,
1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea, hexamethylphosphortriamide, phenol, m-cresol, p-Cresol, p-chlorophenol, anisole and the like are used.

What is important in the present invention is the manner in which the tetracarboxylic dianhydride is added after the amine is dissolved in the solvent, and at least a part of 3,3 ', 4,4'-biphenyltetracarboxylic acid is added. An acid dianhydride is added in advance to cause a reaction. The 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride to be added in advance is preferably at least 0.1 mole times the dissolved diamine. If the amount to be added in advance is too small, a good film cannot be obtained when a film is formed from the obtained amic acid. When the diamine is divided and charged, this amount may be 0.1 mol times or more of the dissolved diamine, and need not be 0.1 mol times or more of all the diamines. In short, before the addition of pyromellitic dianhydride in the reaction solution, at least a specific amount of all diamines present in the solution, preferably 0.1 mol times or more of 3,3 ', 4,4'-biphenyl It is important to react tetracarboxylic dianhydride.

The temperature for synthesizing the polyamic acid is generally from -70 ° C to 100 ° C, usually from 0 ° C to 80 ° C. If the reaction temperature is too low, the reaction does not proceed, while if it is too high, imidization proceeds too much, which is not preferable. The concentration of the reaction solution is generally 1 to 50% by weight, and if the concentration is outside this range, it is difficult to form a film. The ratio of the total acid dianhydride to the total diamine is usually about 1: 0.8 to 0.8: 1, especially about 1: 0.9 to 0.8: 1.
0.9: 1. When applying the obtained polyamic acid to a metal foil, the method for applying the same is not particularly limited, and a known coating device such as a comma coater, a knife coater, a roll coater, a reverse coater, and a die coater can be used. The varnish-coated metal foil is heated for drying and imidizing the varnish, and a known method such as hot air, hot nitrogen, far-infrared ray, or high frequency can be used as the heating method. When the polyamic acid is imidized by drying, generally, most of the solvent is removed at 100 to 220 ° C. for a desired time. Further, the mixture is heated to 220 to 450 ° C. to sufficiently remove the solvent and perform imidization. Preferably the hot air temperature is 22
0 ° C. or lower, the wind speed is 3 m / min or higher, and the solvent concentration is 1% or lower. After reducing the residual solvent in the formed film to 50% or lower, more preferably 30% or lower, particularly preferably 10% or lower. Further, it is preferable to reduce the residual solvent to 0.5% or less at a temperature of 300 to 450 ° C. in view of the physical properties of the resulting polyimide film, particularly in terms of elongation. Here, the residual solvent is a value represented by the following equation.

In the present invention, the polyimide film formed on the metal foil may be composed of two or more polyimide films. For example, after forming a film of the first layer of polyimide precursor (meaning polyamic acid, polyimide mixed system or polyamic acid before sufficiently polyimide) on a metal foil, the first layer of polyimide precursor After forming a second layer of polyimide precursor film having a composition different from that of the body film, imidation may be performed to form a two-layer polyimide film. Also in such a case, there is no particular limitation on the method of applying the polyamic acid and the method of heating, and the above-mentioned known device can be used. The thickness of the polyimide film formed on the metal foil is not particularly limited, but usually 3 to 100 μm
And more generally in the range of 5 to 60 μm. Although the thickness of the metal foil can be arbitrarily selected, it is usually in the range of 9 to 150 μm, and more generally in the range of 9 to 50 μm. In addition, in order to increase the adhesive strength between the heat-resistant polymer and the metal foil which are in direct contact with the metal foil, a simple metal or an oxide or alloy thereof on the metal foil, for example, a simple copper when the metal foil is a copper foil It is also preferable to form an inorganic substance such as copper oxide, a nickel-copper alloy, and a zinc-copper alloy. Further, in addition to inorganic substances, a coupling agent such as aminosilane, epoxysilane, mercaptosilane or the like is formed on a metal foil, or a heat-resistant polymer or a precursor solution thereof is mixed with the above-mentioned coupling agent to form a heat-resistant polymer. It is also possible to improve the adhesive strength between the coalesced and the metal foil. In addition, thermoplastic polyimide with excellent adhesive properties (such as LARC-TPI manufactured by Mitsui Toatsu Chemical Co., Ltd.)
It may be present as a so-called anchor coat layer. Hereinafter, an example of an embodiment of the present invention will be described with reference to examples.

[0016]

The present invention will be further described with reference to the following examples. Rotational viscosity in the examples was measured at 25 ° C. using an E-type viscometer.
The intrinsic viscosity was measured in N-methyl-2-pyrrolidone at a concentration of 0.5% at 35 ° C. The dimensional stability of FCL was performed according to IPC-FC-241A.
The properties of the polyimide film were determined according to ASTM MD-882. The soldering iron resistance was adjusted such that the tip of the soldering iron had a radius of curvature of 0.5 mm and the angle of the tip of the iron was 30 ° so that the load on the tip became 100 gr. The temperature at the tip is adjusted to 325 ° C. ± 25 ° C., and a soldering iron is set upright on a 25 μm thick film made of polyimide alone. The case where the film was not broken for more than 5 seconds after setting the soldering iron was evaluated as ○, and the case where the film was broken within 5 seconds was evaluated as ×. The compounds were abbreviated as follows. In formula (1), the diamine to which X is directly connected is m-BP, and p-phenylenediamine is PP.
D, bisaminophenyl ether is converted to ODA, 3,3 ', 4,4'-
Biphenyltetracarboxylic dianhydride was BPDA and pyromellitic dianhydride was PMDA-methyl-2-pyrrolidone NMP.

Example 1 47.1 grams of m-BP (25 mole% of total diamines)
40.8 grams of PPD (75 mole% of total diamine), N
After dissolving in 860 g of MP with stirring at 60 ° C., 37.7 g of BPDA (0.25 mol times of total diamine, 26 mol% of total acid anhydride) was added and reacted at 60 ° C. for 30 minutes. Next, 51.7 g (48 mol% of the total anhydride) of PMDA was added and reacted at 60 ° C. for 60 minutes. Thereafter, 37.7 g of BPDA was added and reacted at 60 ° C. for 120 minutes to synthesize a polyamic acid varnish. The rotational viscosity of the obtained varnish was 17
The 000 CPS and the intrinsic viscosity η were 1.13. The obtained varnish was rolled with an applicator using a rolled copper foil having a thickness of 18 μm (Nikko Kyoishi (
Co., Ltd., BHY-13T) and air at 130 ° C (wind speed 5
m / min, solvent concentration 0.2%) to remove 5
After drying to 5%, air at 160 ° C (wind speed 5m /
Min, solvent concentration 0.2%) over 13 minutes
Allowed to dry. Thereafter, the temperature was raised from 300 ° C. to 390 ° C. in a nitrogen atmosphere over 5 minutes to dry the residual solvent to 0.02%, and at the same time, the imidization was completed. The thickness of the FCL thus obtained was 43 μm. This FCL
Table 1 shows the dimensional stability of the polyimide film and the characteristics of the polyimide film after copper foil etching.

Example 2 18.0 grams of ODA (18 mole% of total diamine), m
14.1 grams of BP (8 mol% of total diamines),
40.8 grams of PPD (74 mole percent of total diamine), N
After dissolving in 800 grams of MP at 60 ° C. with stirring, 37.7 grams of BPDA (0.25% of total diamine)
The reaction was continued for 30 minutes while maintaining the temperature at 60 ° C. Next, 51.7 g (48 mol% of the total anhydride) of PMDA was added and reacted at 60 ° C. for 60 minutes. Thereafter, 37.7 g of BPDA was added and reacted for 120 minutes while maintaining the temperature at 60 ° C. to synthesize a polyamic acid varnish. The rotational viscosity of the obtained varnish was 15,000 CPS, and the intrinsic viscosity η was 1.10. The obtained varnish was coated on an 18 μm-thick rolled copper foil (manufactured by Nikko Kyoishi Co., Ltd., BHY-13T) with an applicator, and air at 130 ° C. (wind speed 5 m / min, solvent concentration 0.2%) The remaining solvent was dried to 60% in about 3 minutes, and further dried to 15% in 160 ° C. air (air velocity 5 m / min, solvent concentration 0.2%) for about 5 minutes. Then, in a nitrogen atmosphere,
Temperature from 390 ° C to 390 ° C over 5 minutes to reduce residual solvent to 0.02
%, And the imidization was completed at the same time. The thickness of the FCL thus obtained was 43 μm. The dimensional stability of the FCL and the characteristics of the polyimide film after the etching of the copper foil were as shown in Table 1, and were excellent characteristics.

Example 3 The polyamic acid varnish obtained in Example 2 was rolled with an applicator to a rolled copper foil having a thickness of 18 μm (manufactured by Nikko Kyoishi Co., Ltd., BH
Y-13T) and air at 130 ° C (wind speed 10m /
Min., Solvent concentration 0.1%) to reduce residual solvent to 70% over about 2 minutes.
And dried at 210 ° C (wind speed 10m / min,
(Solvent concentration: 0.1%) and the residual solvent was dried to 10% over about 4 minutes. Thereafter, the temperature is reduced from 300 ° C. to 430 in a nitrogen atmosphere.
C., and the imidization was completed at the same time as drying to 0.01% or less of the residual solvent. The thickness of the FCL thus obtained was 43 μm. The dimensional stability of this FCL and the characteristics of the polyimide film after copper foil etching were as shown in Table 1, and were excellent characteristics.

Example 4 The polyamic acid varnish obtained in Example 2 was coated with a stainless steel foil having a thickness of 30 μm (Nissin Steel Co., Ltd.) using an applicator.
Co., Ltd., SUS304), dried with a 130 ° C. air (wind speed 10 m / min, solvent concentration 0.1%) to 55% of residual solvent over about 4 minutes, and further dried at 170 ° C. air (air speed 1%).
(0 m / min, solvent concentration: 0.1%) and the residual solvent was dried to 12% over about 5 minutes. Then, at 300 ° C in a nitrogen atmosphere
To 430 ° C. to dry the residual solvent to 0.01% or less, and at the same time complete the imidization. The thickness of the thus obtained polyimide / stainless-foil laminate was 55 μm. When a stainless steel circuit was drawn on this laminate and energized to form a stainless sheet heating element,
It turned out that it can withstand 50 degreeC. The dimensional stability of this laminate and the properties of the polyimide film after stainless steel etching were as shown in Table 1, and were excellent for a sheet heating element.

Comparative Example 1 18.0 g of ODA, 14.1 g of m-BP,
40.8 grams of PPD, 60 in 800 grams of NMP
After dissolving with stirring at a temperature of 5 ° C., 51.7 g of PMDA was added and reacted at 60 ° C. for 60 minutes. Thereafter, 75.4 g of BPDA was added, and the mixture was reacted for 120 minutes while maintaining the temperature at 60 ° C. to synthesize a polyamic acid varnish.
The rotational viscosity of the obtained varnish is 13000 CPS, the intrinsic viscosity η is 1.
03. The obtained varnish is applied with an applicator to a thickness of 1
8 μm rolled copper foil (Nikko Kyoishi Co., Ltd., BHY-13T) is coated and air at 130 ° C. (wind speed 5 m / min, solvent concentration 0.2
%) In about 4 minutes to dry the residual solvent to 60%.
The residual solvent was dried to 15% with air at 160 ° C. (wind speed 5 m / min, solvent concentration 0.2%) for about 5 minutes. afterwards,
In a nitrogen atmosphere, the temperature was raised from 300 ° C. to 390 ° C. over 5 minutes to dry the residual solvent to 0.02%, and at the same time the imidization was completed. The thickness of the FCL thus obtained is 4
It was 3 μm. The dimensional stability of this FCL and the characteristics of the polyimide film after copper foil etching are as shown in Table 1. Although the dimensional stability is little different from that of Example 2, the elongation and breaking strength of the polyimide film are reduced and the FCL is reduced. It can be seen that the film has completely unfavorable characteristics.

Comparative Example 2 The varnish obtained in Example 2 was applied with an applicator to a thickness of 18 μm.
m of rolled copper foil (BHY-13T), and dried at 165 ° C. in air (wind speed 2 m / min, solvent concentration 5%) for about 12 minutes to 18% of residual solvent. Then, in a nitrogen atmosphere,
The temperature was gradually raised from 00 ° C to 390 ° C over 5 minutes to dry the residual solvent to 0.05%, and at the same time, the imidization was completed. The thickness of the FCL thus obtained was 43 μm. The dimensional stability of this FCL and the characteristics of the polyimide film after copper foil etching are as shown in Table 1, and the film characteristics are excellent. However, the dimensional stability of FCL was greatly reduced as compared with Example 2 and the operation was finished.

Comparative Example 3 The varnish obtained in Example 2 was applied with an applicator to a thickness of 18 μm.
m of rolled copper foil (BHY-13T), dry the remaining solvent to 90% with 130 ° C air (wind speed 5m / min, solvent concentration 0.1%) for about 2 minutes, and further air at 240 ° C. (Wind speed 5
m / min, solvent concentration 0.1%) over 1
Dried to 0%. Then, at 300 ° C in a nitrogen atmosphere
To 390 ° C. over 5 minutes to reduce residual solvent to 0.1.
Imidization was completed at the same time as drying to 05%. The thickness of the FCL thus obtained was 43 μm.
The dimensional stability of the FCL and the characteristics of the polyimide film after copper foil etching are as shown in Table 1, and the film characteristics are excellent. However, the dimensional stability of the FCL was greatly reduced as compared with Example 2, and the operation was finished.

COMPARATIVE EXAMPLE 4 16.6 g of m-BP (9 mol% of all diamines)
49.8 grams of PPD (91 mole% of total diamine), N
After dissolving in 774 grams of MP with stirring at 60 ° C., 37.7 grams of BPDA (0.2% of total diamine)
(5 mol times) and reacted at 30 ° C. for 30 minutes. Next, 51.7 grams of PMDA was added and reacted at 60 ° C. for 60 minutes. After that, 3 BPDA
7.7 g was added and reacted for 120 minutes while maintaining at 60 ° C. to synthesize a polyamic acid varnish. The rotation viscosity of the obtained varnish was 16000 CPS, and the intrinsic viscosity η was 1.12. The obtained varnish is coated on an 18 μm-thick rolled copper foil (manufactured by Nikko Kyoishi Co., Ltd., BHY-13T) using an applicator, and air is applied at 130 ° C. (wind speed 5 m / min, solvent concentration 0.2%). The residual solvent was dried to 60% in about 4 minutes, and further dried to 16% in 160 ° C. air (wind velocity 5 m / min, solvent concentration 0.2%) in about 5 minutes. Thereafter, the temperature was gradually raised from 300 ° C. to 390 ° C. in a nitrogen atmosphere over 5 minutes to dry the residual solvent to 0.02%, and at the same time complete the imidization. The thickness of the polyimide / copper foil laminate (hereinafter abbreviated as FCL) thus obtained was 44 μm. The dimensional stability of the FCL and the characteristics of the polyimide film after copper foil etching are as shown in Table 1. The dimensional stability of the FCL is excellent as in Example 1, but the film characteristics lack flexibility. .

Comparative Example 5 47.1 grams of m-BP (25 mole% of total diamine)
40.8 grams of PPD (75 mole% of total diamine), N
After dissolving in 908 grams of MP at 60 ° C. with stirring, 122.6 grams of BPDA (0.8% of total anhydride)
(5 mol times) and reacted at 90 ° C. for 90 minutes. Next, 16.4 g of PMDA was added and reacted for 90 minutes while maintaining the temperature at 60 ° C. to synthesize a polyamic acid varnish. The rotational viscosity of the obtained varnish was 12,500 CPS, and the intrinsic viscosity η was 1.03. The obtained varnish was rolled with an applicator using an 18 μm-thick rolled copper foil (manufactured by Nikko Kyoishi Co., Ltd., BHY-13).
T) and dried with air at 130 ° C. (wind speed 5 m / min, solvent concentration 0.2%) to 55% of residual solvent over about 4 minutes,
Furthermore, air of 160 ° C. (wind speed 5 m / min, solvent concentration of 0.
2%) to dry the residual solvent to 13% over about 5 minutes.
Thereafter, the temperature was gradually raised from 300 ° C. to 390 ° C. in a nitrogen atmosphere over 5 minutes to dry the residual solvent to 0.02%, and at the same time complete the imidization. The thickness of the polyimide / copper foil laminate thus obtained was 43 μm. Table 1 shows the dimensional stability of the FCL and the characteristics of the polyimide film after etching the copper foil. FC with poor hand soldering resistance
L was not a preferable film.

Comparative Example 6 m-BP: 47.1 grams, PPD: 40.8 grams,
After dissolving in 806 grams of NMP at 60 ° C. with stirring, 21.9 grams of BPDA (0.15 grams of total diamine)
The reaction was continued for 90 minutes while maintaining the temperature at 60 ° C. Next, 91.6 g (85 mol% of the total acid anhydride) of PMDA was added, and the mixture was reacted for 90 minutes while maintaining the temperature at 60 ° C. to synthesize a polyamic acid varnish. The rotational viscosity of the obtained varnish was 17,500 CPS, and the intrinsic viscosity η was 1.17.
Met. The obtained varnish is applied with an applicator to a thickness of 18
μm rolled copper foil (manufactured by Nippon Kyoishi Co., Ltd., BHY-13T) and air at 130 ° C. (wind speed 5 m / min, solvent concentration 0.2
%) In about 4 minutes to dry the residual solvent to 55%.
The residual solvent was dried to 16% with air at 160 ° C. (wind speed 5 m / min, solvent concentration 0.2%) over about 5 minutes. afterwards,
In a nitrogen atmosphere, the temperature was gradually raised from 300 ° C. to 390 ° C. over 5 minutes to dry the residual solvent to 0.04%, and at the same time the imidization was completed. The thickness of the FCL thus obtained was 44 μm. Table 1 shows the dimensional stability of the FCL and the characteristics of the polyimide film after etching the copper foil. The film had a low elongation and was not a preferable film as FCL.

[0027]

[Table 1]

[0028]

The present invention provides a novel method for synthesizing a copolyamic acid varnish having a specific composition, and a novel method for applying the varnish to a metal foil, followed by drying and imidization. It is.

According to the present invention, a polyimide film / metal foil laminate having both excellent dimensional stability and film characteristics can be manufactured, and is extremely useful in the fields of electronics and electric industry such as printed circuit boards and sheet heating elements. I have to say that there is.

Continuation of Front Page (72) Inventor Hideaki Oikawa 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Examiner, Mitsui Toatsu Chemicals Co., Ltd. Mayumi Koishi (56) References JP-A-6-212142 (JP, A) JP-A Heihei JP-A-4-334089 (JP, A) JP-A-4-153224 (JP, A) JP-A-4-50279 (JP, A) JP-A-60-203638 (JP, A) JP-A-6-192639 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 15/08 C08G 73/10-73/16

Claims (8)

(57) [Claims] 1. At least pyromellitic dianhydride 20 to 8
An acid anhydride consisting of 0 mol% and 80 to 20 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 50 to 80 mol% of p-phenylenediamine and the following formula (formula 1): di amine consisting of diamine 50 to 20 mole% represented by the chemical formula 1], the polyamic acid obtained by reacting in a solvent is coated on a metal foil, then a characterized by being heated to dry imidized Polyimide film / metal foil laminate. Embedded image (Wherein, X represents a direct bond, a hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene, a carbonyl group, a thio group or a sulfonyl group.) 2. The method for producing a polyimide film / metal foil laminate according to claim 1, wherein at least a part of 3,3 ′, 4,4′- A method for producing a polyimide film / metal foil laminate, characterized in that after adding and reacting biphenyltetracarboxylic dianhydride, a polyamic acid reacted with pyromellitic dianhydride is applied to a metal foil. 3. A method for producing a polyimide film / metal foil laminate according to claim 1, wherein a hot air used to dry imidize polyamic acid in the process of producing the polyimide film / metal foil laminate. The temperature is 220 ° C. or less, the wind speed is 3 m / min or more, and the solvent concentration is 1% or less.
A method for producing a laminate of a polyimide film and a metal foil, comprising: reducing the residual solvent of a film to be formed to 50% or less, and further reducing the residual solvent to 0.5% or less at a temperature of 300 ° C. or higher. 4. A reaction in which at least a part of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride is first added to a solution in which the amine is dissolved in advance, and the mixture is reacted. The method for producing a polyimide film / metal foil laminate according to claim 3, wherein the polyamic acid reacted with the substance is applied to the metal foil. 5. 50-80 mol% of p-phenylenediamine,
30 to 5 mol% of a diamine represented by the following formula (Formula 1) and [Chemical Formula 2], and 20 to 15 mol% of bisaminophenyl ether
The polyimide film / metal foil laminate according to claim 1, wherein a diamine comprising: Embedded image (In the formula, X represents a direct bond, a hydrocarbon residue having 1 to 10 carbon atoms, a hexafluorinated isopropylidene, a carbonyl group, a thio group or a sulfonyl group.) 6. The method for producing a polyimide film / metal foil laminate according to claim 5, wherein at least a part of 3,3 ′, 4,4′- A method for producing a polyimide film / metal foil laminate, characterized in that after adding and reacting biphenyltetracarboxylic dianhydride, a polyamic acid reacted with pyromellitic dianhydride is applied to a metal foil. 7. A method for producing a polyimide film / metal foil laminate according to claim 5, wherein in the process of producing the polyimide film / metal foil laminate, hot air used for drying and imidizing polyamic acid is used. The temperature is 220 ° C. or less, the wind speed is 3 m / min or more, and the solvent concentration is 1% or less.
A method for producing a laminate of a polyimide film and a metal foil, comprising: reducing the residual solvent of a film to be formed to 50% or less, and further reducing the residual solvent to 0.5% or less at a temperature of 300 ° C. or higher. 8. A solution in which said amine has been previously dissolved, and at least a portion of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride is added thereto and reacted, and then pyromellitic dianhydride is added. The method for producing a polyimide film / metal foil laminate according to claim 7, wherein the polyamic acid reacted with the substance is applied to the metal foil.