KR20200120506A - Multilayer black polyimide film and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a multi-layered black polyimide film having excellent alkali resistance and superior optical and mechanical properties, and to a manufacturing method thereof. According to the present invention, the multi-layered black polyimide film comprises 45-85 wt% of a core layer, and 10-40 wt% of the sum of first and second skin layers, based on the total weight of the multi-layered black polyimide film in which the first and second skin layers are formed around the core layer, and further comprises 5-15 wt% of a black pigment.

Description

Multi-layered black polyimide film and its manufacturing method {MULTILAYER BLACK POLYIMIDE FILM AND MANUFACTURING METHOD OF THE SAME}

The present invention relates to a polyimide film and a method for manufacturing the same, and more particularly, to a black polyimide film having a multilayer structure having excellent alkali resistance and excellent optical and mechanical properties, and a method for manufacturing the same.

In general, polyimide resin refers to a high heat-resistant resin prepared by imidizing polyamic acid prepared by polymerizing dianhydride and diamines by ring closure dehydration.

Such polyimide resins are insoluble, ultra-high heat-resistant resins, and have excellent properties in terms of heat oxidation resistance, radiation resistance, low temperature characteristics, and chemical resistance, so they are applied to high-tech heat-resistant materials such as automobile materials and aviation materials, or are applied to insulating coatings, insulating films, and semiconductors. , It is used in a wide range of fields, such as being applied to electronic materials such as electrode protective films of LCDs. In particular, recently, as a polyimide film, it is widely used as a coverlay to protect electronic components such as lead frames of printed wiring boards. .

On the other hand, when a polyimide film is used as a coverlay, it must undergo manufacturing processes of printed wiring boards such as a drilling process, a plating process, a desmear process, and a cleaning process, and in this process, it is inevitable to be exposed to an alkaline solution. Problems arise.

However, general polyimide films have disadvantages that are very vulnerable to an alkaline environment such as decomposition or degeneration when exposed to an alkaline environment, and therefore, due to these disadvantages, the thickness of the polyimide film becomes thinner or its properties change, resulting in deterioration of its function as a coverlay. There is a problem in which the reliability of electronic products manufactured using the same is significantly lowered, and the need for a technology capable of solving this problem is on the rise.

The matters described in the background art are provided to help understanding the background of the invention, and may include matters other than the prior art already known to those of ordinary skill in the field to which this technology belongs.

Korean Registered Patent Publication No. 10-0767208

Accordingly, in order to solve the above problems, the present invention has excellent alkali resistance, so that even when exposed to an alkaline environment, decomposition and denaturation do not occur, so that the thickness is thin or its properties do not change, and at the same time, optical properties such as transmittance, mechanical strength and elasticity , An object of the present invention is to provide a multilayered black polyimide film having excellent mechanical properties and a manufacturing method thereof.

The polyimide film of the present invention for achieving the above object includes 45 to 85 weight of the core layer based on the total weight of the multilayered black polyimide film in which the first skin layer and the second skin layer are formed around the core layer. %, and 10 to 40% by weight of the sum of the first and second skin layers, and 5 to 15% by weight of a black pigment.

The multi-layered black polyimide film of the present invention is applied to electronic products and undergoes various manufacturing processes such as a drilling process, plating process, desmear process, and washing process, and has excellent alkali resistance even when exposed to an alkaline environment. Since this does not occur, the thickness is reduced or its characteristics do not change, and it is possible to solve the decrease in reliability of electronic products due to deformation of the polyimide film.

In addition, the alkali resistance is excellent, and optical and mechanical properties such as transmittance, mechanical strength, and elasticity are also stable, so it can be more usefully applied to electronic products.

1 is a schematic diagram of a black polyimide film according to an embodiment of the present invention.
2 is a schematic diagram of a coextrusion device used when manufacturing a black polyimide film according to an embodiment of the present invention.
3 is a flowchart of a method of manufacturing a black polyimide film according to an embodiment of the present invention.

Hereinafter, embodiments and examples of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms, and is not limited to the embodiments and examples described herein. Throughout this specification, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

The present invention relates to a multi-layered black polyimide film having excellent alkali resistance and excellent optical and mechanical properties, and a method of manufacturing the same.

1 is a schematic diagram of a black polyimide film according to an embodiment of the present invention.

As shown in Fig. 1, the multilayered black polyimide film of the present invention includes a core layer (1), a first skin layer (2), and a second skin layer (3). It is preferable to have a three-layer structure in which the first skin layer 2 is formed on one side of the layer 1 and the second skin layer 3 is formed on the other side.

The core layer 1 may be included in an amount of 45 to 85% by weight based on the total weight of the multilayered black polyimide film.

This is, when the core layer 1 is included in an amount of less than 45% by weight, alkali resistance may be excellent, but there is a problem that mechanical strength and elasticity are deteriorated. When it is included in an amount exceeding 85% by weight, the degree to which alkali resistance is desired This is because there is a problem that cannot be reached.

The sum of the weight% of the first skin layer 2 and the second skin layer 3 may be included in an amount of 10 to 40% by weight based on the total weight of the multilayered black polyimide film.

This is a problem that when the sum of the first skin layer 2 and the second skin layer 3 is included in less than 10% by weight, the alkali resistance does not reach the desired degree, and contains more than 40% by weight. In this case, the alkali resistance may be excellent, but there is a problem that the mechanical strength and the elastic modulus are lowered.

On the other hand, it is preferable that the weight ratio of the first skin layer 2 and the second skin layer 3 is 1:1.

Meanwhile, the core layer 1, the first skin layer 2, and the second skin layer 3 are preferably prepared by imidizing a polyamic acid solution prepared by polymerization of dianhydride and diamine.

Here, as the dianhydride, pyromellitic dianhydride (PMDA) or 3,3',4,4'-biphenyltetracarboxylic dianhydride (3,3',4,4'-biphenyltetracarboxylic dianhydride, BPDA) may contain at least one aromatic dianhydride selected from.

Diamines include p-phenylene diamine (p-PDA), oxydianiline (4,4'-oxydianiline, ODA), or 4,4'-(1,3-phenylenedioxy) dianiline ( At least one aromatic diamine selected from 1,3-Bis(4-aminophenoxy)benzene, TPER) may be included.

However, more preferably, the core layer 1 is a polyamic acid prepared by selecting and polymerizing pyromellitic dianhydride (PMDA) as a dianhydride, and p-phenylenediamine (p-PDA) and oxydianiline (ODA) as diamines. It is preferable to imidize a mixed acid solution and prepare it in order to secure alkali resistance.

As described above, when p-phenylenediamine (p-PDA) and oxydianiline (ODA) are used as the diamine of the core layer 1, 100 mol% of the total content of the diamine component of the core layer 1 As a reference, the content of p-phenylenediamine (p-PDA) may be 25 mol% or more and 40 mol% or less, and the content of oxydianiline (ODA) may be 60 mol% or more and 75 mol% or less.

And the first skin layer (2) and the second skin layer (3) are prepared by imidizing polyamic acid solutions having the same components as each other, and more specifically, 3,3',4,4'-biphenyl as a dianhydride. It is produced by imidizing a polyamic acid solution prepared by selecting and polymerizing tetracarboxylic dianhydride (BPDA) and 4,4'-(1,3-phenylenedioxy) dianiline (TPER) as diamine. It is preferable to ensure alkalinity.

On the other hand, it is preferable that the multilayered black polyimide film of the present invention further includes a black pigment for implementing a black color of the film and maintaining low gloss.

The black pigment is preferably contained in an amount of 5 to 15% by weight, more preferably 5 to 10% by weight, based on the total weight of the multilayered black polyimide film.

Such a black pigment may be included in any one or more of the core layer 1, the first skin layer 2, and the second skin layer 3.

For example, it may be included in any one or more of the first skin layer 2 or the second skin layer 3 except for the core layer 1, and the first skin layer 2 and the second skin layer ( 3) may be included in both, and in this case, the black pigment may be included in the first skin layer 2 and the second skin layer 3 with the same weight.

Meanwhile, the black pigment is preferably carbon black.

In addition, the black pigment preferably has an average particle diameter of several µm or less for thinning of the film, more preferably 0.1 to 5 µm. Such a black pigment may be mixed with a polyamic acid solution in the form of a black crude liquid dispersed in a polar solvent, and a separate dispersant may be added together to improve the dispersibility of the black pigment.

In addition, an imidation catalyst and a dehydrating agent may be additionally added. The imidation catalyst used is from the group consisting of quinoline, isoquinoline, β-picoline, pyridine, imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole and benzimidazole At least one selected, and anhydrous acid, especially acetic anhydride, may be used as the dehydrating agent, but is not limited thereto.

The core layer (1) of the multi-layered black polyimide film of the present invention contains a dehydrating agent and an imidation catalyst, but the first skin layer (2) and the second skin layer (3) contain the imidation catalyst. It may or may not include, and may not include the dehydrating agent.

When the first skin layer 2 and the second skin layer 3 contain the imidization catalyst, the imidization included in the first skin layer 2 and the second skin layer 3 The content of the catalyst may be 0.5 to 0.7 mol% compared to the varnish of the first skin layer 2 and the second skin layer 3.

When the content of the imidation catalyst exceeds 0.7 mol%, a difference in imidization rate between the skin layer and the core layer occurs, resulting in a divided layer.

The content of the imidization catalyst relative to the varnish of the core layer included in the core layer 1 is the first skin layer 2 included in the first skin layer 2 and the second skin layer 3 And the content of the imidization catalyst relative to the varnish of the second skin layer 3.

For example, the content of the imidization catalyst contained in the first skin layer 2 and the second skin layer 3 is the varnish of the first skin layer 2 and the second skin layer 3 If the ratio is 0.5 mol%, the content of the imidization catalyst included in the core layer 1 may be 0.5 mol% compared to the varnish of the core layer 1.

In addition, the content of the dehydrating agent may be 1 mol% or more and 3 mol% or less compared to the banana ash of the core layer 1.

When the content of the dehydrating agent is less than 1 mol%, gel is generated in the varnish when the content exceeds 3 mol%.

The multilayered black polyimide film of the present invention preferably satisfies the condition of having an alkali resistance of 65% or more and a mechanical strength of 180 MPa or more, and more preferably, a condition of an alkali resistance of 70% or more.

In addition, it is preferable that the multilayered black polyimide film of the present invention satisfies the condition of having an alkali resistance of 65% or more and an elastic modulus of 2.4 GPa or more.

The multi-layered black polyimide film of the present invention described so far can be manufactured using a coextrusion method.

2 is a schematic diagram of a coextrusion device used when manufacturing a black polyimide film according to an embodiment of the present invention.

As shown in Figure 2, the co-extrusion method is to fill the storage tanks 4 and 5 with a polyamic acid solution or a polyimide resin prepared by imidizing it, and then use a coextrusion die 6 to multi-layer on the casting belt. It is a method of producing a polyimide film having a multilayer structure by curing after extruding, and has high productivity, and different types of polyimide resins are mixed between interfaces, thereby ensuring high interfacial adhesion reliability.

3 is a flowchart of a method of manufacturing a black polyimide film according to an embodiment of the present invention.

As shown in FIG. 3, in the method of manufacturing a multilayered black polyimide film of the present invention, a first solution, which is a first polyimide resin prepared by imidizing a first polyamic acid solution or a first polyamic acid solution, is used as a first solution. The first filling step (S100) of filling the storage tank 4, a second solution of a second polyimide resin prepared by imidizing the second polyamic acid solution or the second polyamic acid solution is filled into the second storage tank 5 The second charging step (S200), the first flow path 6-1 connected to the first storage tank 4, the second flow path 6-2 and the third flow path 6 connected to the second storage tank 5, respectively. 3) coextrusion step (S300) of coextruding the first solution and the second solution through the coextrusion die 6 each formed therein, and a curing step of curing the first solution and the second solution that are coextruded ( S400).

The first polyamic acid solution is for forming the core layer 1, and is preferably prepared by polymerizing pyromellitic dianhydride (PMDA), p-phenylenediamine (p-PDA), and oxydianiline (ODA). Do.

The second polyamic acid solution is for forming the first skin layer 2 and the second skin layer 3, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4 It is prepared by polymerizing,4'-(1,3-phenylenedioxy)dianiline (TPER).

The black pigment may be included in at least one of the first polyamic acid solution and the second polyamic acid solution.

Meanwhile, when the first polyamic acid solution is used as the first solution and the second polyamic acid solution is used as the second solution, the first solution and the second solution are coextruded before the curing step (S400). It is preferable to further include an imidization step (S350) of imidization.

Hereinafter, the present invention will be described in more detail using Preparation Examples, Comparative Examples and Examples. The following Preparation Examples, Comparative Examples and Examples are for illustration of the present invention, and the scope of the present invention is not limited thereto.

Manufacturing example

A first polyamic acid solution was prepared by mixing a solution prepared by polymerization of pyromellitic dianhydride (PMDA), p-phenylenediamine (p-PDA), and oxydianiline (ODA) and a black crude liquid containing carbon black. Was prepared.

2nd polyamic acid solution by polymerization of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4,4'-(1,3-phenylenedioxy) dianillin (TPER) Was prepared.

A multi-layered black in which the first and second skin layers are formed around the core layer by coextrusion, imidization, and curing of the previously prepared first polyamic acid solution and the second polyamic acid solution through a co-extrusion method. A polyimide film was prepared.

However, the core layer was prepared by coextrusion of the first polyamic acid solution, and the first skin layer and the second skin layer were prepared by coextrusion of the second polyamic acid solution.

Comparative Examples and Examples

Prepared by the above-described preparation example, with respect to the total weight of the multilayered black polyimide film, the weight% of the core layer, the weight% of the sum of the first and second skin layers, and the weight% of carbon black are shown in Table 1 below. And it was prepared by adjusting as shown in Table 2.

In Examples 1 to 4 and Comparative Examples 1 to 4 shown in Table 1 below, a dehydrating agent and an imidization catalyst were added only to the core layer, and a dehydrating agent and an imidization catalyst were not added to the first and second skin layers.

The contents of the dehydrating agent and the imidization catalyst added to the core layer were 2 mol% and 0.5 to 0.7 mol%, respectively, relative to the number of moles of the polyamic acid varnish in the core layer.

Isoquinoline (IQ) or β-picoline (BP) was used as the imidation catalyst, and acetic anhydride was used as the dehydrating agent.

In addition, in Examples 1 to 4 and Comparative Examples 1 to 4, when the content of PMDA in the core layer is 100 mol%, the content of ODA and p-PDA is 100 mol% of the total content of the diamine component of the core layer. They were 75 mol% and 25 mol%, respectively.

In the skin layer, when the BPDA content was 100 mol%, the TPER content was 100 mol%.

division Core layer [% by weight] The sum of the first skin layer and the second skin layer [% by weight] Core layer
Carbon black [% by weight] PMDA+ODA+p-PDA BPDA+TPER Example 1 71 20 9 Example 2 66 25 9 Example 3 61 30 9 Example 4 56 35 9 Comparative Example 1 81 10 9 Comparative Example 2 41 50 9 Comparative Example 3 85 10 5 Comparative Example 4 45 50 5

In Examples 5 to 11 and Comparative Examples 6 to 9 shown in Table 2 below, a dehydrating agent and an imidation catalyst were added to the core layer, and only an imidation catalyst was added to the first and second skin layers.

Comparative Example 5 consisted of only a core layer, and a dehydrating agent and an imidization catalyst were added to the core layer as in other comparative examples.

Acetic anhydride was used as the dehydrating agent added to the core layer, and the content was 2 mol% compared to the varnish of the core layer.

To the core layer, the same amount of the content of the imidization catalyst compared to the skin layer varnish added to the skin layer shown in Table 2 was added. That is, in the case of Example 5, an imidization catalyst of 0.7 mol% compared to the core layer varnish was added to the core layer.

In addition, in Examples 5 to 12 and Comparative Examples 5 to 9, when the PMDA content in the core layer was 100 mol%, the contents of ODA and p-PDA were 75 mol% and 25 mol%, respectively.

In Examples 5 to 12 and Comparative Examples 6 to 9, when the BPDA content was 100 mol% in the skin layer, the TPER content was 100 mol%.

division Core layer [% by weight] With the first skin layer
The sum of the second skin layers [% by weight] Skin layer varnish contrast
Catalyst (mol%) Core layer
Carbon black [% by weight] PMDA+ODA+p-PDA BPDA+TPER BP or IQ Example 5 81 10 0.7 9 Example 6 81 10 0.5 9 Example 7 71 20 0.7 9 Example 8 71 20 0.5 9 Example 9 61 30 0.7 9 Example 10 61 30 0.5 9 Example 11 51 40 0.7 9 Example 12 51 40 0.5 9 Comparative Example 5 91 - - 9 Comparative Example 6 81 10 0.3 9 Comparative Example 7 71 20 0.3 9 Comparative Example 8 61 30 0.3 9 Comparative Example 9 51 40 0.3 9

Tables 3 and 4 below show the alkali resistance, transmittance, mechanical strength, and elastic modulus of the black polyimide films of Examples 1 to 12 and Comparative Examples 1 to 9 prepared as in Tables 1 and 2 as shown in the following experimental method. This is a table showing the experimental results.

Alkali resistance test method

After corona treatment on both sides of the black polyimide film, the black polyimide film, bonding sheet (adhesive) and copper foil structure were bonded by applying a pressure of 50 kgf at 160°C for 30 minutes using a hot press to bond them to a flexible circuit board (hereinafter, FCCL) Make a sample. Thereafter, the FCCL cut into 4*10cm was exposed to 10% NaOH solution at 55°C for 3 minutes, and the desmear solution (10% NaMnO ₄ + 4% NaOH) exposed at 55°C for 5 minutes, and then washed twice. Repeat.

The thickness of the black polyimide film before exposure to NaOH solution and desmear solution was compared with the degree of change in thickness after exposure, and the degree of change in thickness after exposure compared to the thickness before exposure was expressed as a percentage.

Transmittance test method

The transmittance of the black polyimide film was measured by ASTM D1003 method in the visible light region using a transmittance measuring device (ColorQuesetXE, manufacturer: HunterLab).

Mechanical strength and modulus test method

The black polyimide film was measured for mechanical strength and modulus of elasticity according to ASTM D882 regulations.

division Alkali resistance [%] After alkali treatment
Transmittance [%] Mechanical strength [MPa] Modulus of elasticity [GPa] Example 1 83 3.0 270 4.0 Example 2 85 2.75 266 3.85 Example 3 87 2.52 261 3.68 Example 4 90 2.16 257 3.57 Comparative Example 1 60 5.13 278 4.3 Comparative Example 2 90 2.25 175 2.3 Comparative Example 3 62 7.46 283 4.3 Comparative Example 4 91 6.13 172 2.3

As shown in Table 3, in the case of the black polyimide films of Examples 1 to 4, all of the alkali resistance was 83% or more, which was very excellent compared to Comparative Examples 1 and 3. The mechanical strength was also more than 250 MPa, and the elastic modulus was also more than 3.5 GPa, indicating that the mechanical stability was also excellent.

On the other hand, in the case of the black polyimide films of Comparative Examples 2 and 4, it can be seen that the alkali resistance is excellent at 90% or more, but the mechanical strength is less than 200 MPa and the elastic modulus is also less than 2.5 GPa, so that the mechanical strength and elastic modulus are significantly reduced. I could confirm.

division Alkali resistance [%] After alkali treatment
Transmittance [%] Mechanical strength [MPa] Modulus of elasticity [GPa] Example 5 75 7.2 265 3.6 Example 6 73 7.7 255 3.3 Example 7 80 5.3 247 3.3 Example 8 78 5.8 237 3.0 Example 9 85 4.1 225 3.0 Example 10 83 4.6 215 2.7 Example 11 90 3.5 190 2.6 Example 12 88 4.0 180 2.4 Comparative Example 5 60 20 290 4.0 Comparative Example 6 65 18 235 2.5 Comparative Example 7 68 16 205 2.3 Comparative Example 8 70 14 185 2.1 Comparative Example 9 72 12 165 1.9

As shown in Table 4, in the case of the black polyimide films of Examples 5 to 12, all of the alkali resistance was 73% or more, it could be seen that superior to Comparative Examples 5 to 9. That is, within the range of the weight ratio of the core layer, the skin layer, and the carbon black of the examples, all the polyimide films having an imidation catalyst content of 0.5 to 0.7 mol% relative to the varnish of the skin layer (first skin layer + second skin layer) are skin layers. Compared to the polyimide film having an imidization catalyst content of 0.3 mol% compared to the varnish, alkali resistance was excellent.

In addition, in the polyimide film composed of the same core layer, the first/second skin layer, and the composition of carbon black (for example, Examples 5 and 6 and Comparative Example 6), the skin layer (first skin layer + agent 2 Skin layer) The polyimide film with an imidation catalyst content of 0.5 to 0.7 mol% compared to the varnish had excellent mechanical strength and elasticity compared to the polyimide film with an imidization catalyst content of 0.3 mol% compared to the skin layer varnish.

That is, as in Examples 5 to 12, the black polyimide films in which 0.5 to 0.7 mol% of the imidation catalyst was added to the skin layer compared to the varnish of the skin layer (first skin layer + second skin layer) were compared to Comparative Examples 6 to 9 Likewise, it exhibited excellent alkali resistance, mechanical strength, and elastic modulus compared to the black polyimide film of the same configuration, except that a smaller amount (0.3 mol%) of the imidation catalyst was included in the skin layer.

In addition, the black polyimide films of Examples 5 to 12 in which the imidation catalyst is included in the skin layer are compared with the black polyimide films of Examples 1 to 4 in which the imidation catalyst is not included in the skin layer. It was found that the interfacial adhesion was improved.

As a result, in the case of a black polyimide film outside the content range according to the present invention, there is a problem that the alkali resistance is low, and even if the alkali resistance is high, the mechanical strength and elastic modulus are deteriorated.

On the other hand, in the case of a black polyimide film satisfying the content range according to the present invention, not only excellent alkali resistance, but also optical and mechanical properties such as transmittance, mechanical strength, and elastic modulus are also quite excellent.

Examples of the multilayered black polyimide film of the present invention and a method for manufacturing the same are only preferred embodiments that enable those skilled in the art to easily implement the present invention, and the above-described embodiments The scope of the present invention is not limited thereto because it is not limited to. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims. In addition, it will be apparent to those skilled in the art that various substitutions, modifications and changes are possible within the scope of the technical spirit of the present invention, and it is obvious that parts that can be easily changed by those skilled in the art are included in the scope of the present invention. .

1: core layer
2: first skin layer
3: second skin layer
4: first storage tank
5: second storage tank
6: coextrusion die
6-1: Euro 1
6-2: 2nd Euro
6-3: 3rd Euro
S100: first charging step
S200: second charging step
S300: coextrusion step
S350: imidization step
S400: curing step

Claims (12)

Based on the total weight of the multilayered black polyimide film in which the first and second skin layers are formed around the core layer,
45 to 85% by weight of the core layer, and
10 to 40% by weight of the sum of the first skin layer and the second skin layer,
Black polyimide film having a multilayer structure, characterized in that it further comprises 5 to 15% by weight of a black pigment. The method of claim 1,
The core layer is a multi-layered black, characterized in that it is prepared from a polyamic acid solution prepared by polymerizing pyromellitic dianhydride (PMDA), p-phenylenediamine (p-PDA) and oxydianiline (ODA). Polyimide film. The method of claim 1,
The first skin layer and the second skin layer are 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4,4'-(1,3-phenylenedioxy)di A multi-layered black polyimide film, characterized in that prepared from a polyamic acid solution prepared by polymerizing aniline (TPER). The method of claim 1,
The black pigment is included in at least one layer selected from the group consisting of the core layer, the first skin layer, and the second skin layer. The method of claim 1,
The black pigment is a multi-layered black polyimide film, characterized in that carbon black. The method of claim 2,
Based on 100 mol% of the total content of the diamine component of the core layer, the content of p-phenylenediamine (p-PDA) is 25 mol% or more and 40 mol% or less, and the content of oxydianiline (ODA) is 60 mol % Or more and 75 mol% or less, wherein the black polyimide film having a multilayer structure. The method of claim 1,
The core layer further comprises a dehydrating agent and an imidization catalyst,
The first skin layer and the second skin layer further include or do not include the imidization catalyst, and do not include the dehydrating agent. The method of claim 1,
The multilayered black polyimide film satisfies the condition of 65% or more alkali resistance and 180 MPa or more mechanical strength, or,
A black polyimide film having a multilayer structure, characterized in that it satisfies the condition of having an alkali resistance of 65% and an elastic modulus of 2.4 GPa or more. The method of claim 7,
The first skin layer and the second skin layer of the multilayered black polyimide film further comprise the imidation catalyst,
The content of the imidization catalyst additionally included in the first skin layer and the second skin layer is 0.5 to 0.7 mol% of the varnish of the first skin layer and the second skin layer. Black polyimide film. The method of claim 9,
A black polyimide film having a multilayer structure, characterized in that it satisfies a condition of 73% or more of alkali resistance. A first polyamic acid solution prepared by polymerizing pyromellitic dianhydride (PMDA), p-phenylenediamine (p-PDA) and oxydianiline (ODA), or an agent prepared by imidizing the first polyamic acid solution A first filling step of filling a first solution, which is a polyimide resin, into a first storage tank;
Second polyamic acid prepared by polymerizing 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and 4,4'-(1,3-phenylenedioxy) dianillin (TPER) A second filling step of filling a solution or a second solution, which is a second polyimide resin prepared by imidizing the second polyamic acid solution, into a second storage tank;
A coextrusion step of coextruding the first solution and the second solution through a coextrusion die having a first flow path connected to the first storage tank, a second flow path connected to the second storage tank, and a third flow path respectively connected to the second storage tank ; And
Including a curing step of curing the coextruded first solution and the second solution,
Any one or more of the first polyamic acid solution and the second polyamic acid solution contains a black pigment. The method of claim 11,
Using the first polyamic acid solution as the first solution,
When using the second polyamic acid solution as the second solution,
And an imidization step of imidizing the first solution and the second solution that have been coextruded before the curing step.

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