WO2020209555A1 - Multilayer polyimide film having excellent dimensional stability and adhesiveness, and method for producing same - Google Patents

Abstract

The present invention provides a multilayer polyimide film and a method for producing same, the multilayer polyimide film comprising: a core portion containing at least a 4,4'-diamino-2,2'-dimethylbiphenyl compound-derived structure; and a skin portion containing at least a 3,5-diaminobenzoic acid compound-derived structure, wherein the glass transition temperature (T_g) of the core portion is 360°C or higher, the glass transition temperature of the skin portion is 300°C or higher, and the adhesiveness is at least 1,000 gf/cm.

Description

Multilayer polyimide film with excellent dimensional stability and adhesion and manufacturing method thereof

The present invention relates to a multilayer polyimide film having excellent dimensional stability and adhesion, and a method of manufacturing the same. More specifically, it includes a core portion including a structure derived from at least 4,4′-diamino-2,2′-dimethylbiphenyl compound and a skin portion including a structure derived from at least 3,5-diaminobenzoic acid compound, and Provided are a multilayer polyimide film having a negative glass transition temperature (T _g ) of 360°C or higher, a skin portion having a glass transition temperature of 300°C or higher, and an adhesive strength of 1,000 gf/cm or higher, and a method for manufacturing the same.

In addition, the multilayer polyimide film of the present invention may have a coefficient of thermal expansion (CTE) of 7.5 ppm or more and 11 ppm or less, and a difference of a molecular orientation ratio (MOR) of 0.005 or less.

In addition, the multilayer polyimide film of the present invention may have an elastic modulus of 6.8 GPa or more and 7.5 GPa or less, and a strength of 360 MPa or more and 440 MPa or less.

That is, the present invention is composed of a core layer having excellent dimensional stability and a skin layer containing a 3,5-diaminobenzoic acid compound to secure adhesion to improve the balance of the entire width of the multilayer polyimide film, so that adhesion and dimensional stability Both of these provide excellent multilayer polyimide films.

Polyimide (PI) is a polymer material with thermal stability based on a rigid aromatic backbone and has excellent mechanical strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of the imide ring.

In addition, it has been in the spotlight as a high-functional polymer material in microelectronics and optical fields with excellent electrical properties such as insulation and low dielectric constants.

For example, in the field of microelectronics, thin circuit boards with high degree of integration and flexibility are being actively developed due to the light weight and miniaturization of electronic products. Accordingly, polyimide which has excellent heat resistance, low temperature resistance, and insulation characteristics, but is easy to bend, is used. It is a trend to be used as a protective film for thin circuit boards.

Such a thin circuit board generally has a structure in which a circuit including a metal foil is formed on a polyimide film, and such a thin circuit board is also referred to as a flexible metal foil laminate in a broad sense. As an example of this, a thin copper plate with metal foil When using, in a narrow sense, it is also referred to as flexible copper clad laminate (FCCL).

As a method of manufacturing a flexible metal foil laminate, for example, (i) casting a polyamic acid, which is a precursor of polyimide, on a metal foil, or coating it, followed by imidization, and (ii) sputtering or plating. A metallization method in which a metal layer is directly provided on the polyimide film, and (iii) a lamination method in which a polyimide film and a metal foil are bonded with heat and pressure through a thermoplastic polyimide are mentioned.

The lamination method has an advantage in that the thickness range of the applicable metal foil is wider than that of the casting method, and the equipment cost is lower than that of the metalizing method. As an apparatus for laminating, a roll lamination apparatus or a double belt press apparatus for continuously laminating while introducing a roll-shaped material is used. Among the above, from the viewpoint of productivity, a thermal roll lamination method using a thermal roll lamination device can be more preferably used.

However, in the case of a laminate, as described above, since a thermoplastic resin is used for bonding the polyimide film and the metal foil, in order to express the thermal adhesion of the thermoplastic resin, the glass transition of the polyimide film is 300°C or higher, in some cases. It is necessary to apply heat of 400°C or higher, which is close to or higher than the temperature (Tg), to the polyimide film.

In general, it is known that the value of the storage modulus of a viscoelastic material such as a polyimide film decreases significantly compared to the value of the storage modulus at room temperature in a temperature range above the glass transition temperature.

That is, when performing a lamination that requires a high temperature, the storage modulus of the polyimide film at high temperature may be significantly lowered, and under a low storage modulus, the polyimide film may become loose and the polyimide film may not exist in a flat form after the end of the lamination. Is high. In other words, in the case of a laminate, it can be said that the dimensional change of the polyimide film is relatively unstable.

Another thing to note is the case where the glass transition temperature of the polyimide film is remarkably low compared to the temperature at the time of lamination. Specifically, in the above case, since the viscosity of the polyimide film is relatively high at the temperature at which the lamination is performed, a relatively large dimensional change may be accompanied, and accordingly, there is a concern that the appearance quality of the polyimide film may be deteriorated after lamination. .

In the case of using the casting method, as a three-layer polyimide film for two-layer FPC, a method of applying a polyamic acid solution to the surface of the polyimide film and drying (imidizing) it to prepare a three-layer polyimide film is mentioned. However, a process of manufacturing a polyimide film and a process of applying and drying (imidizing) a polyamic acid solution on the surface of the polyimide film are required, and there are cases where there are multiple processes and cost-up. There was (for example, see Patent Document 1).

Further, as a three-layer polyimide film for a two-layer FPC, a method of producing a three-layer polyimide film by casting a polyamic acid solution in a plurality of layers simultaneously on a support, peeling from the support after drying, and heat treatment is mentioned. In some cases, the polyimide layer directly in contact with the top is partially affixed on the support, or a difference in peel strength occurs between the polyimide layer in contact with the support and the polyimide layer on the opposite side (for example, patent See Documents 2 and 3).

Therefore, there is a high need for a technology that can greatly improve fairness by solving the above problems.

[Prior technical literature]

[Patent Literature]

1. Japanese Unexamined Patent Application Publication No. Hei 9-116254 (published on May 2, 1997)

2. Japanese Unexamined Patent Application Publication No. Hei 7-214637 (published on August 15, 1995)

3. Japanese Unexamined Patent Application Publication No. Hei 10-138318 (published on May 26, 1998)

An object according to an aspect of the present invention is to provide a multilayer polyimide film having excellent dimensional stability and adhesion, and an effective manufacturing method thereof, and specifically, to determine the type of dianhydride monomer, the type of diamine monomer, and the blending ratio thereof. , In addition, due to the composition of polyimide resins of different compositions in multiple layers, it has a desired glass transition temperature, has a high storage modulus at high temperature, and also has excellent adhesion while minimizing dimensional changes by mitigating thermal stress. It is to provide a multi-layered polyimide.

An object according to another aspect of the present invention is to provide a flexible copper clad laminate having a relatively small dimensional change and excellent appearance quality, including a multilayer polyimide film satisfying desired physical properties.

Accordingly, the present invention has a practical purpose to provide specific examples thereof.

In order to achieve the above object, the present invention, 4,4′-diamino-2,2′-dimethylbiphenyl (4,4′-Diamino-2,2′-dimethylbiphenyl; m-Tolidine), paraphenylene Diamine-derived structure and pyromellitic dianhydride containing at least one selected from the group consisting of diamine (p-phenylenediamine; p-PDA) and 4,4′-oxydianiline (ODA) (pyromellitic dianhydride; PMDA) and at least one selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (3,3′,4,4′-Biphenyltetracarboxylic dianhydride; BPDA) It is present in contact with at least one outer surface of the core portion and the core portion including a dianhydride-derived structure containing, 3,5-diaminobenzoic acid (3.5-DABA), paraphenylenediamine Diamine-derived structures including (p-phenylenediamine; p-PDA) and 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA), 3, 3′,4,4′-biphenyltetracarboxylicdianhydride (3,3′,4,4′-Biphenyltetracarboxylic dianhydride; BPDA) and 3,3′,4,4′-benzophenonetetracarboxylicdianhydride Ride (3,3',4,4'-Benzophenonetetracarboxylic dianhydride; BTDA), including a skin portion containing a dianhydride-derived structure containing at least one selected from the group consisting of, and the glass transition temperature of the core portion (T _g ) Is 360° C. or higher, a glass transition temperature of the skin portion is 300° C. or higher, and an adhesive strength of 1,000 gf/cm or higher is provided.

The thickness of the core portion and the skin portion may be present in a ratio of 6:4 to 9:1, and more preferably, the glass transition temperature of the skin portion is preferably 300° C. to 380° C., and the adhesive strength may be 1,000 gf/cm or more. In addition, the skin portion may contact at least one outer surface of the core portion and a surface opposite to the outer surface of the core portion, thereby providing a multilayer polyimide film present on both surfaces of the core portion.

Another embodiment of the present invention is a diamine containing at least one selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine, and 4,4′-oxydianiline. Preparation prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of monomers, pyromellitic dianhydride, and 3,3′,4,4′-biphenyltetracarboxylicdianhydride in a solvent Obtaining 1 polyamic acid; Preparing a first polyimide prepared by imidizing a first polyamic acid; Diamine monomers including 3,5-diaminobenzoic acid, paraphenylenediamine and 4,4′-oxydianiline and pyromelliticdianhydride, 3,3′,4,4′-biphenyltetracarboxylicdian To obtain a second polyamic acid prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of hydride and 3,3′,4,4′-benzophenonetetracarboxylicdianhydride in a solvent step; Preparing a second polyimide prepared by imidizing a second polyamic acid; Co-extrusion with a second discharge part for discharging the second polyimide so as to contact the first polyimide from at least one side of the first discharge part for discharging the first polyimide; method for producing a multilayer polyimide film comprising Provides.

In addition, another embodiment of the present invention includes at least one selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine, and 4,4′-oxydianiline. Prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of a diamine monomer and a pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylicdianhydride in a solvent Obtaining one first polyamic acid; Diamine monomers including 3,5-diaminobenzoic acid, paraphenylenediamine and 4,4′-oxydianiline and pyromelliticdianhydride, 3,3′,4,4′-biphenyltetracarboxylicdian To obtain a second polyamic acid prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of hydride and 3,3′,4,4′-benzophenonetetracarboxylicdianhydride in a solvent step; Coextrusion with a second discharge part for discharging the second polyamic acid so as to contact the first polyamic acid from at least one side of the first discharge part for discharging the first polyamic acid; It provides a method for producing a multilayer polyimide film comprising; imidizing the coextruded polyamic acid. Preferably, the step of coextrusion and the step of imidizing the coextruded polyamic acid may be performed simultaneously.

The multilayer polyimide film has an adhesive strength of 1,000 gf/cm or more, a glass transition temperature (T _g ) of the core part made from the first polyamic acid is 360° C. or more, and the glass transition temperature of the skin part made from the second polyamic acid (T _g ) is characterized in that 300 ℃ or more.

The first discharge part is located on the opposite side of the surface in contact with the second discharge part, and the third discharge part further discharges the second polyimide or the second polyamic acid so as to contact the other surface of the first polyimide or the first polyamic acid. Can include.

Each of the first polyamic acid and the second polyamic acid may further include any one selected from the group consisting of an imidation catalyst, a dehydrating agent, a curing agent, a filler, and an additive in which one or more of them are mixed.

Another embodiment of the present invention provides a flexible metal foil laminate comprising a multilayer polyimide film and an electrically conductive metal foil.

Another embodiment of the present invention provides an electronic component including a flexible metal foil laminate.

As described above, the present invention is due to a combination of specific dianhydride monomers and diamine monomers and a specific mixing ratio thereof, and by laminating polyimide films of different compositions, excellent adhesion and desired glass It has a transition temperature, inherently high storage modulus at high temperature, and, in addition, it is possible to provide a multilayer polyimide film having excellent dimensional stability and an effective manufacturing method thereof by improving the variation in shrinkage rate by width direction by easing thermal stress.

The present invention may also provide a flexible copper clad laminate having excellent appearance quality, including the multilayer polyimide film as described above.

Hereinafter, the functions and effects of the invention will be described in more detail through specific embodiments of the invention. However, these embodiments are only presented as examples of the invention, and the scope of the invention is not determined thereby.

Hereinafter, embodiments of the present invention will be described in more detail in the order of "multilayer polyimide film", "manufacturing method of multilayer polyimide film" and "flexible metal foil laminate" according to the present invention.

Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Therefore, the configuration of the embodiments described in the present specification is only one of the most preferred embodiments of the present invention, and does not represent all of the technical spirit of the present invention, and various equivalents and modifications that can replace them at the time of application It should be understood that examples may exist.

In the present specification, expressions in the singular include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include" or "have" are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

Multilayer polyimide film

The multilayer polyimide film according to the present invention,

4,4′-diamino-2,2′-dimethylbiphenyl (4,4′-Diamino-2,2′-dimethylbiphenyl; m-Tolidine), paraphenylenediamine (p-PDA), and Diamine-derived structures containing at least one selected from the group consisting of 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) and 3,3′ ,4,4′-biphenyltetracarboxylic dianhydride (3,3′,4,4′-Biphenyltetracarboxylic dianhydride; BPDA) Core containing a dianhydride-derived structure containing at least one selected from the group consisting of part; And

Present in contact with at least one outer surface of the core part, 3,5-diaminobenzoic acid (3.5-DABA), paraphenylenediamine (p-PDA), and 4,4' -Diamine-derived structure including oxydianiline (4,4′-oxydianiline; ODA) and pyromellitic dianhydride (PMDA), 3,3′,4,4′-biphenyltetracarboxylicdian Hydride (3,3',4,4'-Biphenyltetracarboxylic dianhydride; BPDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (3,3',4,4'-Benzophenonetetracarboxylic dianhydride) It includes a skin portion comprising a dianhydride-derived structure containing at least one selected from the group consisting of BTDA).

The skin part is present on at least one outer surface of the core part and may exist in the form of a 2-layer film, and more preferably, a form in contact with one outer surface of the core part and the rear surface of the outer surface, that is, at least It may exist in the form of a three-layer film in which the skin portion is in contact with both outer surfaces.

The thickness of the core portion and the skin portion may exist in a ratio of 6:4 to 9:1. When the thickness of the core portion is less than 6 parts or exceeds 9 parts, the dimensional stability may be deteriorated, and when the thickness of the skin part is less than 1 part or exceeds 4 parts, the adhesion characteristics may be deteriorated.

As an embodiment of the present invention for a multilayer polyimide film, each dianhydride monomer, diamine monomer, and a blending ratio thereof constituting the core portion and the skin portion will be described in detail through the following non-limiting examples.

<Diamine monomer>

Diamine monomers that can be used in the present invention are 4,4′-diamino-2,2′-dimethylbiphenyl (4,4′-Diamino-2,2′-dimethylbiphenyl; m-Tolidine), 3,5-dia Minobenzoic acid (3,5-diaminobenzoic acid; 3.5-DABA), 4,4'-oxydianiline (4,4'-oxydianiline; ODA), 3,4'-oxydianiline (3,4'-oxydianiline) , 4,4-diaminobiphenyl-3,3-tetracarboxylic acid (4,4-diaminobiphenyl-3,3-tetracarboxylic acid; DATA), paraphenylenediamine (p-phenylenediamine; p-PDA), m -Phenylenediamine (m-PDA), p-methylenediamine (p-methylenediamine; p-MDA), metamethylenediamine (m-methylenediamine; m-MDA), and can be selected from the group of mixtures of one or more of them. have.

In a preferred embodiment of the present invention, the diamine monomer constituting the core portion is 1 selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine, and 4,4′-oxydianiline. It may contain more than one species. In the case of including all the structures derived from the three diamine compounds, the glass transition temperature (T _g ) characteristic of the polyimide film is expressed at 360° C. or higher, and it is preferable to manufacture a core portion having high dimensional stability.

More preferably, the diamine monomer constituting the core portion of the present invention may be paraphenylenediamine and 4,4'-oxydianiline.

When the diamine monomer of the core part is made of only paraphenylenediamine and 4,4'-oxydianiline, the content of the paraphenylenediamine is 60 mol% or more based on 100 mol% of the total content of the diamine monomer of the core part 80 Mole% or less, and the content of the 4,4'-oxydianiline may be 20 mol% or more and 40 mol% or less.

In another preferred example of the present invention, the diamine monomer constituting the skin portion may include 3,5-diaminobenzoic acid, paraphenylenediamine, and 4,4′-oxydianiline. In order to improve the adhesion of the polyimide, it is advantageous to include a monomer containing a hydrophilic functional group such as 3,5-diaminobenzoic acid. In addition, in the case of including all three diamine compound-derived structures as described above, the adhesive strength is excellent at 1,000 gf/cm or more, and the glass transition temperature of the skin part can be formed at 300°C or more, preferably 300°C to 380°C. It is possible to improve the deviation of the shrinkage rate by location due to the glass transition temperature in the process.

In addition, the content of 3,5-diaminobenzoic acid is 3 mol% or more and 15 mol% or less, and the content of paraphenylenediamine is 60 mol% or more based on 100 mol% of the total content of the diamine monomer of the skin part of the present invention. It is 80 mol% or less, and the content of the 4,4'-oxydianiline may be 15 mol% or more and 35 mol% or less.

<Dianhydride monomer>

The dianhydride monomer that can be used in the present invention is 3,3',4,4'-biphenyltetracarboxylic dianhydride (3,3',4,4'-Biphenyltetracarboxylic dianhydride; BPDA), pyromellitic Pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (3,3′,4,4′-Benzophenonetetracarboxylic dianhydride; BTDA), oxydiphthalic anhydride It may be selected from the group of oxydiphthalic anhydride (ODPA) and mixtures of one or more mixtures thereof.

In a preferred embodiment of the present invention, the dianhydride monomer constituting the core portion is one or more selected from the group consisting of pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylicdianhydride. Can include.

When the dianhydride monomer of the core part is made of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylicdianhydride, the total content of the dianhydride monomer of the core part is 100 mol% Based on the content of the pyromellitic dianhydride is 40 mol% or more and 60 mol% or less, and the content of the 3,3′,4,4′-biphenyltetracarboxylicdianhydride is 40 mol% or more 60 It may be less than or equal to mole %.

In another preferred embodiment of the present invention, the dianhydride monomer constituting the skin part is pyromellitic dianhydride, 3,3′,4,4′-biphenyltetracarboxylicdianhydride and 3,3′,4, It may include at least one selected from the group consisting of 4'-benzophenone tetracarboxylicdianhydride.

More preferably, the dianhydride monomer constituting the skin part of the present invention is 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic. It may be a dianhydride.

When the dianhydride monomer of the skin part is composed of only 3,3',4,4'-biphenyltetracarboxylicdianhydride and 3,3',4,4'-benzophenonetetracarboxylicdianhydride, the The content of the 3,3′,4,4′-biphenyltetracarboxylicdianhydride is 90 mol% or more and 99 mol% or less, based on 100 mol% of the total content of the dianhydride monomer of the skin portion, and 3, The content of 3′,4,4′-benzophenonetetracarboxylicdianhydride may be 1 mol% or more and 10 mol% or less.

In addition, such a multilayer polyimide film,

(a) the glass transition temperature (T _g ) of the core portion is 360°C or higher, the glass transition temperature of the skin portion is 300°C or higher, preferably 300°C to 380°C,

(b) the adhesion is 1,000 gf/cm or more, preferably 1,400 gf/cm or more,

(c) CTE is 7.5 ppm or more and 11 ppm or less, and MOR difference is 0.005 or less,

(d) The elastic modulus is 6.8 GPa or more and 7.5 GPa or less, and the strength is 360 MPa or more and 440 MPa or less.

In this regard, in the case of a multilayer polyimide film that satisfies all of the above conditions, it can be used as a substrate film for a flexible metal foil laminate, an insulating film, a protective film, etc. In addition, in the process of forming a film with a flexible metal foil laminate, the shrinkage rate varies by width direction It is possible to implement a stable circuit by minimizing the problem of dimensional change caused by the problem or the problem of lifting due to a decrease in adhesion.

A multilayer polyimide film having all of these conditions is a novel polyimide film that has not been known so far, and the above conditions will be described in detail below.

<Glass transition temperature>

In the present invention, the glass transition temperature can be obtained from the storage modulus and the loss modulus measured by a dynamic viscoelasticity measuring device (DMA), and in detail, the top peak of tan δ, which is a value obtained by dividing the calculated loss modulus by the storage modulus, The glass transition degree can be calculated. Since the glass transition temperature is related to the heat resistance of the polyimide film, in order to improve dimensional stability at high temperatures when applied to a copper clad laminate or the like, a higher value is preferable.

However, using a conventional multilayer polyimide film manufactured by coating thermoplastic polyimide (TPI) on a core polyimide film or laminating after each of a TPI film and a core film is used, a flexible copper clad plate (Flexible Copper Clad) In the case of manufacturing Laminate: FCCL), due to the glass transition temperature of the core polyimide (360°C or higher), distortion and dimensional balance problems may occur due to variations in shrinkage rate by position and width direction in the film forming process. Due to this, variations in the mechanical properties of the multilayer polyimide film and the coefficient of interlayer thermal expansion (CTE) may occur.

In addition, in a multilayer polyimide film, it is difficult to balance physical properties such as the highest level of glass transition ionicity, dielectric constant, dielectric loss rate, or adhesion. This is due to the chemical stability of the imide group that improves the glass transition temperature of the polyimide film. , Since the imide group exhibits polarity, the moisture absorption rate can be increased, and the improvement of the moisture absorption rate is predicted to be related to the weakening of dielectric properties and adhesion properties.

However, when simply increasing the glass transition temperature of the polyimide film in order to solve this problem, there may be a problem that the adhesive strength is weakened. In addition, when a skin layer or an adhesive layer having adhesiveness is formed between the core layer of the multilayer polyimide film and the metal foil, it is necessary to consider the problem that the shrinkage rates are different from each other due to the difference in thermal expansion coefficient between the skin layer and the core layer.

Therefore, in order to overcome this problem, the present invention provides a polyimide film in which both glass transition ionicity and adhesive strength are compatible with desirable levels. Specifically, the polyimide film according to the present invention controls the glass transition temperature of the polyimide resin constituting the core part and the skin part, respectively, and coextrusion them, thereby forming TPI on the core polyimide film having a low glass transition temperature. Compared to the case of a multilayer polyimide film manufactured by coating or laminating, adhesion and dimensional stability may be improved.

Therefore, in the multilayer polyimide film according to a preferred embodiment of the present invention, the glass transition temperature (T _g ) of the core portion may be 360°C or higher, the glass transition temperature of the skin portion may be 300°C or higher, and preferably the glass transition temperature of the skin portion is It may be 300 ℃ or more to 380 ℃ or less.

When the glass transition temperature of the resin constituting the multilayer polyimide film of the core part or the skin part, respectively, is lower than the above range, when the multilayer polyimide film is manufactured through coextrusion, the viscosity of the polyimide film becomes relatively high. Molding control can be difficult. In addition, when FCCL is manufactured by a thermal lamination method, the polyimide film becomes excessively loose, and appearance defects such as swells or wrinkles are formed on the surface of the polyimide film after the film forming process is completed, and large dimensional changes may be accompanied. This is a cause of impairing the appearance quality, and it is not preferable because the effect of improving the dimensional stability due to the improvement of the shrinkage variation may be halved. In addition, after heat application by such a thermal lamination method, that is, even when adhesion is completed, the core layer or the skin layer of the polyimide film begins to soften due to the residual heat contained in the polyimide film, causing the dimensional change to gradually increase. May be.

On the other hand, when the glass transition temperature of the polyimide resin constituting the skin part is higher than the above range, the temperature at which the adhesive layer is softened is too high, so when the glass transition temperature is increased, the adhesive strength may decrease due to the increase in the glass transition temperature. It is not preferable because the stress is not sufficiently relieved and the difference in heat shrinkage may also cause a large dimensional deviation. That is, if it is out of the above range, it may cause the physical properties of the multilayer polyimide film to deteriorate outside the range in which the adhesive force and dimensional stability are properly maintained.

<Adhesion>

The adhesion may include both the adhesion between the core part and the skin part of the multilayer polyimide film, the adhesion between the same or different material layers in contact with the polyimide film, and preferably the adhesion with the electrically conductive metal foil.

As an embodiment of the present invention, a method of measuring adhesion was used as a peel test method through Innoflex adhesion. Put Innoflex (1mil, Epoxy type, Innox product) on the flexible metal clad laminated laminated copper foil on both sides of the multilayer polyimide (PI) film or multilayer polyimide film of the present invention, and place the PVC film and the PI film for protection on both sides at 160℃ After the temperature was raised to, it was thermocompressed at a pressure of 10Kgf/cm ^{2 for} 30 minutes. The film was cut into 13mm width and cut, followed by a 180° Peel test.

The multilayer polyimide film prepared according to an embodiment of the present invention preferably has an adhesive strength of 700 gf/cm or more, preferably 1,000 gf/cm or more, and even more preferably 1,400 gf/cm or more.

Manufacturing method of multilayer polyimide film

In order to obtain the multilayer polyimide film of the present invention,

(1) A polyamic acid solution obtained by going through the steps of adding a diamine monomer and a dianhydride monomer to an organic polar solvent, and adding a diamine monomer and a dianhydride monomer to an organic polar solvent, and imidizing it A coextrusion manufacturing method is preferred in which the polyimide of each core part and the skin part is filled and discharged into a resin reservoir.

However, in some cases, (2) a co-extrusion manufacturing method in which the polyamic acid solution is filled into the polyamic acid solution reservoir in the core part and the skin part and discharged, or simultaneously imidized may be used, and (3) the core It is also possible to use a co-extrusion-flexible coating manufacturing method in which the negative polyamic acid is imidized and cast while simultaneously discharging with the polyamic acid solution of the skin part.

First, the multilayer polyimide film of the present invention is obtained from first and second polyamic acid solutions, which are precursors of first and second polyimides constituting the core part and the skin part, respectively.

The polyamic acid solution is a dianhydride monomer obtained by dissolving a monomer compound in which the aromatic or aliphatic diamine monomer and the aromatic or aliphatic dianhydride monomer are substantially equimolar amount in an organic solvent, and the obtained polyamic acid organic solvent solution under controlled temperature conditions. And the diamine monomer is prepared by stirring until the polymerization is complete.

Preferably, the first polyamic acid solution constituting the core portion is one selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine, and 4,4′-oxydianiline. Diamine-derived monomers including the above and a dianhydride-derived monomer comprising at least one selected from the group consisting of pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylicdianhydride It can be prepared by polymerization in a solvent.

In addition, the second polyamic acid solution constituting the skin part is a diamine-derived monomer including 3,5-diaminobenzoic acid, paraphenylenediamine and 4,4′-oxydianiline, and a pyromellitic dianhydride, 3,3. A dianhydride-derived monomer containing at least one selected from the group consisting of',4,4'-biphenyltetracarboxylicdianhydride and 3,3',4,4'-benzophenonetetracarboxylicdianhydride It may be desirable to prepare by polymerizing in a solvent.

The polyamic acid solution is usually obtained with a solid content of 5 to 35% by weight, preferably 10 to 30% by weight, and in the case of a concentration in this range, the polyamic acid solution obtains an appropriate molecular weight and solution viscosity.

The solvent for synthesizing the polyamic acid solution is not particularly limited, and any solvent may be used as long as it dissolves the polyamic acid. Specifically, the solvent may be an organic polar solvent, and specifically, aprotic polarity It may be a solvent (aprotic polar solvent), preferably an amide-based solvent. For example, N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide, N-methyl-pyrrolidone (NMP), gamma butyrolactone (GBL), Diglyme. It may be one or more selected from the group consisting of, but is not limited thereto, and may be used alone or in combination of two or more as necessary. In one example, N,N-dimethylformamide and N,N-dimethylacetamide may be preferably used as the solvent.

In the manufacturing step of the polyamic acid, all monomers may be added at once or each of the monomers may be added sequentially, depending on the type of the monomer and the properties of the desired polyimide film, and in this case, partial polymerization between the monomers may occur.

In addition, in the polyamic acid solution manufacturing process, a filler may be added for the purpose of improving various properties of the film, such as sliding properties, thermal conductivity, conductivity, corona resistance, and loop hardness.

The filler to be added is not particularly limited, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like.

The particle diameter of the filler is not particularly limited, and can be determined according to the properties of the film to be modified and the type of filler to be added.

In general, the average particle diameter may be 0.05 to 100 µm, preferably 0.1 to 75 µm, more preferably 0.1 to 50 µm, and particularly preferably 0.1 to 25 µm.

If the particle diameter is less than this range, the modification effect is difficult to appear, and if it exceeds this range, the surface properties may be greatly impaired or the mechanical properties may be greatly reduced.

Further, the amount of the filler to be added is not particularly limited, and can be determined by the film properties to be modified or the filler particle size.

In general, the amount of the filler added may be 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, more preferably 0.02 to 80 parts by weight, based on 100 parts by weight of the polyimide.

If the amount of the filler added is less than this range, the effect of modifying by the filler is difficult to appear, and if it exceeds this range, the mechanical properties of the film may be greatly impaired.

The method of adding the filler is not particularly limited, and any known method may be used.

The first and second polyamic acid solutions prepared as described above are coextruded in a solution state or imidized at the same time as the coextrusion process to prepare a multilayer polyimide, or imidized with the first and second polyimide, respectively. Multilayer polyimide can be manufactured by filling each resin in a resin storage tank and coextrusion to form a core portion and a skin portion.

As for the method of imidizing a polyamic acid solution to prepare a polyimide, a conventionally known method can be used, specifically, a thermal imidation method, a chemical imidation method, or a combination of a thermal imidation method and a chemical imidation method. The complex imidization method is mentioned.

The thermal imidation method is a method of imidizing a polyamic acid solution only by heating without using a catalyst such as a dehydrating agent. The polyamic acid is gradually heated in a temperature range of 40°C to 400°C, preferably 40°C to 300°C. This is a method of obtaining a polyimide resin in which polyamic acid is imidized by heat treatment for 1 to 8 hours.

The chemical imidization method is a method of promoting imidization of a polyamic acid solution using a catalyst such as a dehydrating agent and/or an imidizing agent.

An example of a chemical imidization method is a composition obtained by mixing additives such as a dehydrating agent, an imidation catalyst, a chemical conversion agent, and a hardener in a polyamic acid solution at low temperature, and a support such as a glass plate, aluminum foil, endless stainless belt, or stainless drum. And/or heat treatment at a temperature range of 40°C to 300°C, preferably 80°C to 200°C, more preferably 100°C to 180°C to activate the dehydrating agent and the imidizing agent to partially cure and/ Alternatively, it is dried to form a gel that is an intermediate having self-supporting properties. Thereafter, it is preferable to include a step of peeling the gel from the support and a step of further heating the gel to imidize and dry the remaining amic acid (hereinafter, also referred to as a "baking process").

In the composite imidization method, after adding a dehydrating agent and an imidation catalyst to the polyamic acid solution, heating at 80 to 200°C, preferably 100 to 180°C, partially curing and drying, heating at 200 to 400°C for 5 to 400 seconds By doing so, a polyimide resin can be obtained.

Accordingly, the first polyamic acid and the second polyamic acid of the present invention are a group consisting of an imidation catalyst, a dehydrating agent, a curing agent, and an additive in which one or more thereof is mixed to facilitate thermal imidization, chemical imidization, or complex imidization. It may further include any one selected from.

Dehydrating agents include, for example, aliphatic acid anhydride, aromatic acid anhydride, N,N'-dialkylcarbodiimide, halogenated lower aliphatic, halogenated lower fatty acid anhydride, arylphosphonic acid dihalide, and thionylhalide, or two of these. And mixtures of more than one species. Among them, aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and lactic acid anhydride, or a mixture of two or more thereof can be preferably used from the viewpoint of availability and cost.

The amount of the dehydrating agent added is preferably in the range of 0.5 to 5 moles, more preferably in the range of 1.0 to 4 moles per 1 mole of the amic acid group in the polyamic acid.

In addition, as an imidizing agent, an aliphatic tertiary amine, an aromatic tertiary amine, a heterocyclic tertiary amine, etc. are used, for example. Among them, those selected from heterocyclic tertiary amines are particularly preferably used from the viewpoint of reactivity as a catalyst. Specifically, quinoline, isoquinoline, β-picoline, pyridine, and the like are preferably used.

In addition, the amount of the imidizing agent added is preferably within the range of 0.05 to 3 moles, and particularly preferably within the range of 0.2 to 2 moles, per 1 mole of the amic acid group in the polyamic acid.

If the dehydrating agent and the imidizing agent are less than the above ranges, chemical imidization is insufficient, fracture during firing, or mechanical strength may decrease.

In addition, when these amounts exceed the above range, imidization proceeds rapidly, and casting into a film form may become difficult, which is not preferable.

In the coextrusion method, a first polyimide resin solution or a precursor thereof, a first polyamic acid solution and a second polyimide resin solution, or a precursor thereof, a second polyamic acid solution, are discharged onto a casting belt using a multilayer coextrusion device. This is a method of manufacturing a multilayer polyimide film by forming a multilayer extruded film, followed by heat drying and curing it. In addition, the coextrusion method includes a first polyimide resin solution or a precursor thereof, a first polyamic acid solution and a second polyimide resin solution, or a precursor thereof, a second polyamic acid solution, using a multilayer coextrusion device. It is also possible to form a multilayered polyimide film by forming a multilayered extruded film by discharging it on top and performing heat drying, curing, and imidation. The coextrusion method has high productivity, and a high interfacial adhesion reliability can be secured by mixing different polyimides between interfaces.

The multilayer coextrusion device for manufacturing the multilayer polyimide film of the present invention includes a first resin reservoir storing a first polyimide or a first polyamic acid solution, and a second resin storing a second polyimide or a second polyamic acid solution. It may include a storage tank, a center layer flow path connected to the first resin storage tank, an outer layer flow path connected to the second resin storage tank, a first discharge part connected to the center layer flow path, and a second discharge part connected to the outer layer flow path.

The second polyimide or second polyamic acid solution discharged from the outer layer passage and the second discharge portion is arranged to contact the first polyimide or first polyamic acid solution discharged from at least one side of the first discharge portion connected to the center layer passage Therefore, the outer layer flow path and the second discharge portion are located close to at least one surface of the center layer flow path and the first discharge portion, and finally, a two-layer coextrusion film may be formed.

In addition, the present invention is more preferably located on both sides of the center layer flow path connected to the first discharge unit and the center layer flow path, and a three-layer coextrusion layer including an outer layer flow path connected to the second discharge unit and the third discharge unit ( It may be a die forming a 3-layer coextrusion film). The third discharge part is located on the rear surface of the surface of the first discharge part in contact with the second discharge part, and the second polyimide or the second polyamic acid discharged from the second discharge part is the first polyimide discharged from the first discharge part, or The second polyimide or the second polyamic acid may be discharged so as to contact another surface of the surface in contact with the first polyamic acid. That is, preferably, the second polyimide or the second polyamic acid forming the skin portion may be positioned on both outer surfaces of the first polyimide or the first polyamic acid forming the core portion.

In addition, according to an embodiment of the present invention, since the first to third discharge units are provided with a heating or curing device, the discharge may be sprayed and imidization may be performed to form a multilayer coextrusion.

The multilayer coextrusion device of the present invention can control the discharge and coextrusion casting speeds of the polyimide resin or polyamic acid solution discharged from the first discharge unit, the second discharge unit and/or the third discharge unit, respectively, and the above-described The thickness ratio between the polyimide layer of the core portion and the polyimide layer of the skin portion can be adjusted by adjusting the solvent content, the polymer solid content, and the like contained in the resin and the solution.

The thickness of the core portion and the skin portion is preferably formed in a ratio of 6:4 to 9:1 in order to improve dimensional stability and adhesion of the multilayer polyimide film.

The multilayer polyimide film manufactured through the multilayer coextrusion device is, if necessary, a temperature control device including a cooling device and a heating device for each of the first polyimide resin and the second polyimide resin solution. The viscosity can be adjusted.

The multilayer extrudate film discharged through the multilayer coextrusion device may be heated and dried to form a multilayer polyimide film, and further imidized as necessary to produce a multilayer polyimide film.

In addition, the present invention may further include the step of expanding and flexing the multi-layered extrudate discharged from the coextrusion device.

Ductile metal foil laminate

The present invention provides a flexible metal foil laminate comprising the above-described multilayer polyimide film and an electrically conductive metal foil.

The metal foil to be used is not particularly limited, but when the flexible metal foil laminate of the present invention is used for electronic devices or electrical devices, for example, copper or copper alloy, stainless steel or alloy thereof, nickel or nickel alloy (alloy 42 Also included), it may be a metal foil containing aluminum or an aluminum alloy.

In general flexible metal foil laminates, copper foils such as rolled copper foil and electrolytic copper foil are often used, and can be preferably used in the present invention.

The flexible copper clad laminate (FCCL) using a polyimide film as an insulating support does not use an adhesive type FCCL and a three-layer structure (Adhesive type) in which copper foil is laminated using an adhesive on the polyimide film. Instead, thermoplastic polyimide (Thermoplastic It can be divided into FCCL having a two-layer structure (TPI adhesive type) in which copper foil is laminated by imparting adhesiveness using a polyimide: TPI) coating layer.

Therefore, the surface of these metal foils or polyimide films may be further coated with a rust prevention layer, a heat-resistant layer, a coating layer, or an adhesive layer.

In the present invention, the thickness of the metal foil is not particularly limited, and any thickness capable of exhibiting a sufficient function according to the application may be used.

In the flexible metal foil laminate according to the present invention, a metal foil is laminated on one side of the multilayer polyimide film, or an adhesive layer containing thermoplastic polyimide is added to one side of the multilayer polyimide film, and the metal foil is attached to the adhesive layer. It may be a laminated structure.

The present invention also provides an electronic component comprising a flexible metal foil laminate as an electrical signal transmission circuit. The electrical signal transmission circuit may be an electronic component that transmits a signal at a high frequency of at least 2 GHz, in detail, a high frequency of at least 5 GHz, and more particularly, a high frequency of at least 10 GHz. The electronic component may be, for example, a communication circuit for a portable terminal, a communication circuit for a computer, or a communication circuit for aerospace, but is not limited thereto.

Manufacturing example

Preparation Example 1: Preparation of the core part (first composition)

After adding 198.23 kg of DMF to a 300 L reactor under a nitrogen atmosphere at 25° C. and dissolving p-PPA and ODA in a desired composition ratio, 16.87 kg of BPDA and 11.79 kg of PMDA were reacted, and 7.53 kg of a PMDA 10% solution was added in portions. While adjusting the viscosity, a polyamic acid solution for a core having a viscosity of about 200,000 cP was obtained.

Preparation Example 2: Preparation of skin part (second composition)

155.49 kg of DMF was added to a 300 L reactor under a nitrogen atmosphere at 25° C., and 4.20 kg of ODA, 0.89 kg of DABA, and 6.17 kg of p-PDA were dissolved in sequence. After reacting 23.19 kg of BPDA, 9.25 kg of BTDA 10% solution was divided. After adjusting the viscosity while adding to obtain a viscosity of about 200,000 cP, 36 g of 0.5 μm spherical silica, 13 kg of isoquinoline and 67 kg of DMF were added to obtain a second polyamic acid solution of 12,000 cp.

Examples and Comparative Examples

The composition and thickness (core part and skin part) of Examples and Comparative Examples corresponding to the multilayer polyimide film of the present invention are shown in Table 1 below.

<Example 1>

The first composition prepared in Preparation Example 1 was added to the first storage tank of the coextrusion die, and the second composition prepared in Preparation Example 2 was added to the second storage tank.

Thereafter, the second composition, the first composition and the second composition were coextruded on the endless belt in that order. At this time, when the first composition was extruded from the first storage tank, a mixture of isoquinoline, dimethylformamide and acetic anhydride was mixed from the catalyst storage tank.

The catalyst, dehydrating agent, and solvent mixture were mixed with the first polyamic acid.

Subsequently, heat treatment was performed at a temperature of about 150° C., and this was heated again from 150° C. to 600° C. in a high-temperature tenter, and then cooled at 25° C. to obtain a 20 μm multilayer polyimide film having a skin part/core part/skin part structure. .

<Examples 2 to 4>

In Preparation Example 1, a multilayer polyimide film was prepared in the same manner as in Example 1, except that the first polyamic acid composition (particularly, the diamine monomer composition) and the core/skin thickness ratio were controlled.

<Comparative Example 1>

A precursor composition obtained by mixing isoquinoline and acetic anhydride as a catalyst with the first polyamic acid prepared in Preparation Example 1 was coated on a SUS plate. Thereafter, heat treatment was performed in a temperature range of 100° C. to 200° C., heated from 200° C. to 600° C. in a high-temperature tenter, and then cooled at 25° C. to obtain a polyimide film.

<Comparative Example 2>

In Preparation Example 2, a precursor composition in which isoquinoline and acetic anhydride were mixed as a catalyst in the second polyamic acid was coated on a SUS plate. Thereafter, heat treatment was performed in a temperature range of 100° C. to 200° C., heated from 200° C. to 600° C. in a high-temperature tenter, and then cooled at 25° C. to obtain a polyimide film.

	Core composition (mol%)		Skin part composition (mole%)		Thickness (μm)
	Dianhydride	Diamine	Dianhydride	Diamine	core	Skin *
Example 1	BPDA(50)/PMDA(50)	ODA(30)/P-PDA(70)	BPDA(97)/BTDA(3)	ODA(25)/DABA(7)/P-PDA(68)	16	4
Example 2	BPDA(50)/PMDA(50)	ODA(30)/P-PDA(70)	BPDA(97)/BTDA(3)	ODA(25)/DABA(7)/P-PDA(68)	15	5
Example 3	BPDA(50)/PMDA(50)	ODA(35)/P-PDA(65)	BPDA(97)/BTDA(3)	ODA(25)/DABA(7)/P-PDA(68)	16	4
Example 4	BPDA(50)/PMDA(50)	ODA(35)/P-PDA(65)	BPDA(97)/BTDA(3)	ODA(25)/DABA(7)/P-PDA(68)	15	5
Comparative Example 1	BPDA(50)/PMDA(50)	ODA(30)/P-PDA(70)	-	-	20	-
Comparative Example 2	BPDA(97)/BTDA(3)	ODA(25)/DABA(7)/P-PDA(68)	-	-	20	-

*Skin thickness: The thickness of the entire skin

<Experimental Example: Evaluation of the properties of a polyimide film>

In order to evaluate the properties of the multilayer polyimide films prepared in Examples 1 to 4 and Comparative Examples 1 and 2, respectively, elastic modulus, strength, adhesion, CTE, orientation analysis and adhesion were measured using the following method, and the results are shown in the following table. It is shown in 2.

-CTE : With TA's Q400 TMA equipment, the diagonal B, which is orthogonal to the diagonal direction A of the side, is heated to 360 degrees at a heating rate of 10 degrees/minute under 0.05N tension, and then cooled at a rate of 10 degrees/minute, and then cooled at room temperature to 10 degrees. The temperature was raised in degrees/minute, and the difference was calculated by measuring the coefficient of thermal expansion in the range of 100 degrees to 200 degrees.

-Orientation analysis : The MOR difference was calculated by measuring both sides and the center with the MOA-7015 equipment of OSI (Prince Measuring Instrument).

-Elastic modulus/strength : It was measured using an Instron (Instron 3365SER) equipment according to the ASTM D 882 measurement method.

- adhesive strength was measured by Innox four Bonding Sheet (BSH-MX-25MP ) and Iljin copper foil 180 using the (ICS) 30MPa (pressure) and then making the FCCL to lamina 60 minutes Instron Corporation 200mm / min condition 3365SER equipment .

	CTE (ppm)	Orientation analysis (MOR difference)	Modulus of elasticity (GPa)	Strength (MPa)	Adhesion (gf/cm)
Example 1	8	0.003	7.5	400	1400
Example 2	8.5	0.0035	7.1	380	1430
Example 3	8.8	0.004	7.1	390	1410
Example 4	9.2	0.0043	6.8	360	1450
Comparative Example 1	7	0.02	8	450	1000
Comparative Example 2	12	0.2	6.5	360	1450

From the results of Table 2, it can be seen that the Examples have excellent performance, particularly in orientation and adhesion. On the other hand, it can be seen that in Comparative Examples 1 to 2, at least one of these characteristics is poor.

That is, Examples 1 to 4 of the present invention all have adhesive strength 1,000 gf/cm or more (especially 1,400 gf/cm or more), CTE 7.5 ppm or more and 11 ppm or less, MOR difference 0.005 or less, modulus of elasticity 6.8 GPa or more and 7.5 GPa or less, strength 360 The range of MPa or more and 440 MPa or less was satisfied.

On the contrary, Comparative Example 1 exhibited excellent CTE, elastic modulus, and strength characteristics compared to the Examples, but exhibited a decreased measured value in MOR difference and adhesion characteristics, and Comparative Example 2 was excellent in adhesion characteristics compared to Examples, but CTE , MOR difference, CTE, and elastic modulus properties showed decreased measured values.

Although one embodiment of the present invention has been described above through the detailed description of the present invention, it is possible for those of ordinary skill in the field to which the present invention belongs to perform various applications and modifications within the scope of the present invention based on the above contents. It will be possible.

The present invention is due to a combination of specific dianhydride monomers and diamine monomers and a specific mixing ratio thereof, and by laminating polyimide films of different compositions, excellent adhesion, while having a desired glass transition temperature, and high temperature In addition, it is possible to provide a multilayer polyimide film having excellent dimensional stability and an effective manufacturing method thereof by improving the deviation of the shrinkage rate in each width direction by easing thermal stress and in addition to it.

The present invention may also provide a flexible copper clad laminate having excellent appearance quality, including the multilayer polyimide film as described above.

Claims (16)

1. 4,4′-diamino-2,2′-dimethylbiphenyl (4,4′-Diamino-2,2′-dimethylbiphenyl; m-Tolidine), paraphenylenediamine (p-PDA), and Diamine-derived structures containing at least one selected from the group consisting of 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) and 3,3′ ,4,4′-biphenyltetracarboxylic dianhydride (3,3′,4,4′-Biphenyltetracarboxylic dianhydride; BPDA) Core containing a dianhydride-derived structure containing at least one selected from the group consisting of part; And

   It is present in contact with at least one outer surface of the core part, 3,5-diaminobenzoic acid (3.5-DABA), paraphenylenediamine (p-PDA), and 4,4 Diamine-derived structures including'-oxydianiline (4,4'-oxydianiline; ODA) and pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic Dianhydride (3,3′,4,4′-Biphenyltetracarboxylic dianhydride; BPDA) and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (3,3′,4,4′-Benzophenonetetracarboxylic dianhydride; BTDA) a multilayer polyimide film comprising; a skin portion including a dianhydride-derived structure including at least one selected from the group consisting of.
2. The method of claim 1,

   The core part is a diamine-derived structure including the paraphenylenediamine and the 4,4′-oxydianiline, and the pyromellitic dianhydride and the 3,3′,4,4′-biphenyltetracarboxylicdian It includes a dianhydride-derived structure including hydride,

   The skin portion is the pyromellitic dianhydride, the 3,3′,4,4′-biphenyltetracarboxylicdianhydride and the 3,3′,4,4′-benzophenonetetracarboxylicdianhydride Multilayer polyimide film comprising a dianhydride-derived structure comprising a.
3. The method of claim 2,

   The content of the pyromellitic dianhydride is 40 mol% or more and 60 mol% or less, based on 100 mol% of the total content of the dianhydride monomer in the core portion, and the 3,3′,4,4′-biphenyltetra The content of carboxylic dianhydride is 40 mol% or more and 60 mol% or less,

   The content of the paraphenylenediamine is 60 mol% or more and 80 mol% or less based on 100 mol% of the total content of the diamine monomer in the core portion, and the content of 4,4′-oxydianiline is 20 mol% or more and 40 mol % Or less,

   The content of the 3,3′,4,4′-biphenyltetracarboxylicdianhydride is 90 mol% or more and 99 mol% or less, based on 100 mol% of the total content of the dianhydride monomer of the skin portion, and the 3 The content of ,3′,4,4′-benzophenonetetracarboxylicdianhydride is 1 mol% or more and 10 mol% or less,

   The content of the 3,5-diaminobenzoic acid is 3 mol% or more and 15 mol% or less, based on 100 mol% of the total content of the diamine monomer of the skin part, and the content of paraphenylenediamine is 60 mol% or more and 80 mol% Or less, wherein the content of the 4,4′-oxydianiline is 15 mol% or more and 35 mol% or less.
4. The method of claim 1,

   A multilayer polyimide film having a thickness of the core portion and the skin portion in a ratio of 6:4 to 9:1.
5. The method of claim 1,

   A multilayer polyimide film having a glass transition temperature (T _g ) of the core portion of 360° C. or more, a glass transition temperature of the skin portion of 300° C. or more, and an adhesive strength of 1,000 gf/cm or more.
6. The method of claim 1,

   A multilayer polyimide film having a CTE of 7.5 ppm or more and 11 ppm or less, a MOR difference of 0.005 or less, an elastic modulus of 6.8 GPa or more and 7.5 GPa or less, and a strength of 360 MPa or more and 440 MPa or less.
7. The method of claim 1,

   The skin portion is a multilayer polyimide film present on both surfaces of the core portion by contacting at least one outer surface of the core portion and a surface opposite to the outer surface of the core portion.
8. Diamine monomer and pyromellitic dianhydride containing at least one selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine and 4,4′-oxydianiline And 3,3′,4,4′-biphenyltetracarboxylicdianhydride; obtaining a first polyamic acid prepared by polymerizing a dianhydride monomer including at least one selected from the group consisting of a solvent;

   Preparing a first polyimide prepared by imidizing the first polyamic acid;

   Diamine monomers including 3,5-diaminobenzoic acid, paraphenylenediamine and 4,4′-oxydianiline and pyromelliticdianhydride, 3,3′,4,4′-biphenyltetracarboxylicdian To obtain a second polyamic acid prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of hydride and 3,3′,4,4′-benzophenonetetracarboxylicdianhydride in a solvent step;

   Preparing a second polyimide prepared by imidizing the second polyamic acid;

   Coextrusion comprising a second discharge part discharging the second polyimide so as to contact the first polyimide from at least one side of the first discharging part discharging the first polyimide; Method of manufacturing.
9. Diamine monomer and pyromellitic dianhydride containing at least one selected from the group consisting of 4,4′-diamino-2,2′-dimethylbiphenyl, paraphenylenediamine and 4,4′-oxydianiline And 3,3′,4,4′-biphenyltetracarboxylicdianhydride; obtaining a first polyamic acid prepared by polymerizing a dianhydride monomer including at least one selected from the group consisting of a solvent;

   Diamine monomers including 3,5-diaminobenzoic acid, paraphenylenediamine and 4,4′-oxydianiline and pyromelliticdianhydride, 3,3′,4,4′-biphenyltetracarboxylicdian To obtain a second polyamic acid prepared by polymerizing a dianhydride monomer containing at least one selected from the group consisting of hydride and 3,3′,4,4′-benzophenonetetracarboxylicdianhydride in a solvent step;

   Coextrusion with a second discharge part for discharging the second polyamic acid so as to contact the first polyamic acid at at least one side of the first discharge part for discharging the first polyamic acid;

   Imidizing the coextruded polyamic acid; a method for producing a multilayer polyimide film comprising.
10. The method according to claim 8 or 9,

    The multilayer polyimide film has an adhesive force of 1,000 gf/cm or more,

    Preparation of a multilayer polyimide film in which the glass transition temperature (T _g ) of the core part prepared from the first polyamic acid is 360°C or higher, and the glass transition temperature (T _g ) of the skin part prepared from the second polyamic acid is 300°C or higher Way.
11. The method according to claim 8 or 9,

    The multilayer polyimide film has a CTE of 7.5 ppm or more and 11 ppm or less, a MOR difference of 0.005 or less, an elastic modulus of 6.8 GPa or more and 7.5 GPa or less, and a strength of 360 MPa or more and 440 MPa or less.
12. The method according to claim 8 or 9,

    The first discharge part is located on a surface opposite to the surface in contact with the second discharge part, and discharges the second polyimide or the second polyamic acid so as to contact the other surface of the first polyimide or the first polyamic acid. A method of manufacturing a multilayer polyimide film further comprising a third discharge unit.
13. The method according to claim 8 or 9,

    The first polyamic acid and the second polyamic acid each further comprises any one selected from the group consisting of an imidization catalyst, a dehydrating agent, a curing agent, a filler, and an additive in which one or more of them are mixed.
14. The method of claim 9,

    The method of manufacturing a multilayer polyimide film wherein the coextrusion and imidization of the coextruded polyamic acid are performed simultaneously.
15. A flexible metal foil laminated plate comprising the multilayer polyimide film according to any one of claims 1 to 7 and an electrically conductive metal foil.
16. An electronic component comprising the flexible metal foil laminate of claim 15.