KR20200052847A - Polyimide Composite Film with Superior Performance for Dielectric Property and Method for Preparing the Same - Google Patents

Abstract

The present invention relates to a polyimide composite film with excellent dielectric properties and a manufacturing method thereof. More specifically, provided is a polyimide composite film comprising: a core layer containing a first polyimide resin; and at least one skin layer containing a second polyimide resin and a fluorine-based resin and formed in a state bonded to at least one surface of the core layer.

Description

Polyimide Composite Film with Superior Performance for Dielectric Property and Method for Preparing the Same}

The present invention relates to a polyimide composite film having excellent dielectric properties and a method for manufacturing the same.

Polyimide (PI) is a polymer having the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials, based on an imide ring with excellent chemical stability along with a rigid aromatic backbone It is material. Therefore, polyimide has been spotlighted as an insulating material for microelectronic components in which the aforementioned properties are strongly required.

In particular, it is used as a material for electronic materials such as flexible printed circuit board (FPCB), tape automated bonding (TAB), and chip on film (COF) due to insulation characteristics peculiar to polyimide.

Examples of the microelectronic component include a thin circuit board having high circuit density and being flexible so as to be able to cope with the weight reduction and miniaturization of electronic products, and the polyimide is widely used as an insulating film for thin circuit boards.

On the other hand, as various functions are embedded in electronic devices, a fast computing speed and a communication speed are required for the electronic devices, and a thin circuit board capable of high-speed communication at a high frequency of 2 GHz or more has been developed to meet this.

In order to realize high-speed high-speed communication, an insulator having a high impedance capable of maintaining electrical insulation even at high frequencies is required.

Impedance is inversely related to the frequency and dielectric constant (dielectric constant, Dk) formed on the insulator, so the dielectric constant should be as low as possible to maintain insulation even at high frequencies.

However, in the case of a conventional polyimide, the dielectric constant is not high enough to maintain sufficient insulation in high-frequency communication with a degree of 3.4 to 3.6, for example, partially or wholly insulation in a thin circuit board in which high-frequency communication of 2 GHz or higher is performed. There is a possibility of loss.

In addition, it is known that the lower the dielectric constant of the insulator, the less the occurrence of undesirable stray capacitance and noise in a thin circuit board, and thus, it is known that the cause of communication delay can be substantially eliminated. As low as possible, the dielectric constant of is recognized as the most important factor in the performance of a thin circuit board.

Therefore, in order to embed more improved performance as an insulating film, it is necessary to develop a polyimide film having a lower dielectric constant.

The present invention provides a polyimide composite film having excellent dielectric constant, dielectric constant and moisture absorption.

In one aspect of the present invention, the polyimide composite film of the present invention includes a core layer and a skin layer as essential factors, and the skin layer may advantageously act to impart a low moisture absorption rate and dielectric constant of the polyimide composite film.

In the present invention, the skin layer includes a second polyimide resin, which may have a coefficient of thermal expansion suitable for adhesion to, for example, a thermoplastic polyimide or metal foil, and based on this, the polyimide composite film is formed from a thermoplastic polyimide or metal foil. When bonding, it has the advantage of excellent dimensional stability. In another aspect, the second polyimide resin, based on its molecular structure, may advantageously have a skin layer having excellent dielectric properties, such as low dielectric constant.

The skin layer also includes a fluorine-based resin capable of inhibiting moisture penetration through its surface and / or diffusion of moisture therein. This can lower the moisture absorption rate, which can adversely affect the dielectric properties, and as a result, the polyimide composite film may have inherent dielectric properties in a desirable form, and in particular, have a low dielectric constant.

The polyimide composite film of the present invention further includes a core layer comprising a first polyimide resin having excellent mechanical rigidity. Based on this core layer, the polyimide composite film can be exhibited with excellent mechanical properties, such as tensile strength and modulus, at desired levels.

In another aspect of the present invention, the present invention provides a production method suitable for implementing a novel polyimide composite film having the above advantages.

In another aspect of the present invention, the present invention provides a flexible metal foil-clad laminate comprising a novel polyimide composite film having the above and a few advantages.

According to these aspects, the above-mentioned conventional problems can be solved, and the present invention has a practical purpose in providing a specific embodiment thereof.

In one embodiment, the invention

A core layer comprising a first polyimide resin; And

A second polyimide resin and a fluorine-based resin, and at least one skin layer formed in a state bonded to at least one surface of the core layer,

The skin layer contains 60% by weight or less of a fluorine-based resin based on the total weight of the skin layer,

A polyimide composite film having a dielectric loss of 0.003 or less, a dielectric constant (Dk) of 3.2 or less, and a moisture absorption rate of 0.6 or less.

In one embodiment, the polyimide composite film according to the present invention may have an elongation of 30% or more, specifically 40% or more.

In one embodiment, the present invention provides a method specialized in preparing the polyimide composite film.

In one embodiment, the present invention provides a flexible metal thin laminate plate comprising the polyimide composite film, an electronic component including the flexible metal thin laminate plate as an electrical signal transmission circuit, wherein the electrical signal transmission circuit is at least 2 GHz. It may be an electronic component that transmits a signal at a high frequency.

Hereinafter, embodiments of the present invention will be described in more detail in the order of “polyimide composite film”, “method for producing polyimide composite film” and “soft metal foil laminate” according to the present invention.

Prior to this, the terms or words used in the present specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Therefore, the configuration of the embodiments described herein 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 this application It should be understood that examples may exist.

In this specification, a singular expression includes a plural expression unless the context clearly indicates otherwise. In this specification, the terms "comprises", "haves" or "have" are intended to indicate the presence of implemented features, numbers, steps, elements or combinations thereof, one or more other features or It should be understood that the existence or addition possibilities of numbers, steps, elements, or combinations thereof are not excluded in advance.

As used herein, "dianhydride (dianhydride)" is intended to include its precursors or derivatives, which may not technically be dianhydrides, but nevertheless react with diamines to form polyamic acids. And this polyamic acid can be converted back to polyimide.

“Diamine” as used herein is intended to include precursors or derivatives thereof, which may not technically be diamines, but will nevertheless react with dianhydrides to form polyamic acids, which are polyamic The acid can be converted back to polyimide.

Where an amount, concentration, or other value or parameter herein is given as an enumeration of ranges, preferred ranges, or preferred upper and lower limits, any upper limit of any pair of any pair, regardless of whether the ranges are disclosed separately or It should be understood to specifically disclose all ranges that can be formed with preferred values and any lower range limits or desirable values. When a range of numerical values is referred to herein, unless stated otherwise, that range is intended to include the endpoints and all integers and fractions within the range. It is intended that the scope of the invention not be limited to the specific values recited when defining a range.

The polyimide composite film of the present invention is excellent in dielectric constant, dielectric constant and moisture absorption.

The polyimide composite film of the present invention includes a core layer and a skin layer as essential factors, and the skin layer can advantageously act to impart a low moisture absorption and dielectric constant of the polyimide composite film.

In the present invention, the skin layer includes a second polyimide resin, which may have a coefficient of thermal expansion suitable for adhesion to, for example, a thermoplastic polyimide or metal foil, and based on this, the polyimide composite film is formed from a thermoplastic polyimide or metal foil. When bonding, it has the advantage of excellent dimensional stability. In another aspect, the second polyimide resin, based on its molecular structure, may advantageously have a skin layer having excellent dielectric properties, such as low dielectric constant.

The skin layer also includes a fluorine-based resin capable of inhibiting moisture penetration through its surface and / or diffusion of moisture therein. This can lower the moisture absorption rate, which can adversely affect the dielectric properties, and as a result, the polyimide composite film may have inherent dielectric properties in a desirable form, and in particular, have a low dielectric constant.

The polyimide composite film of the present invention further includes a core layer comprising a first polyimide resin having excellent mechanical rigidity. Based on this core layer, the polyimide composite film can be exhibited with excellent mechanical properties, such as tensile strength and modulus, at desired levels.

1 is a schematic view of a co-extruder.

Polyimide composite film

The polyimide composite film according to the present invention may be a multilayer composite film having a thickness of 10 to 100 μm, specifically 10 to 75 μm, and more specifically 10 to 50 μm.

The polyimide composite film of the present invention,

A core layer comprising a first polyimide resin; And

It may include a second polyimide resin and a fluorine-based resin, and may include at least one skin layer formed in a state bonded to at least one surface of the core layer.

In one specific example, the first polyimide resin and the second polyimide resin may be prepared by polymerization of a diamine monomer and a dianhydride monomer, respectively.

In one specific example, the diamine monomer,

1,4-diaminobenzene (or paraphenylenediamine, PDA, PPD), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzo Diaminodiphenyl ethers, such as diacid (or DABA), 4,4'-diaminodiphenyl ether (or oxidianiline, ODA), 3,4'-diaminodiphenyl ether, 4,4'-dia Minodiphenylmethane (or 4,4'-methylenediamine, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl , 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy- 4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4'-dia Minobenzanilide, 3,3'-dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dime Thoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4,4'-dia Minodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4, 4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diamino Diphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) Propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3 , 3,3-hexafluoropropane, 3,3'-diaminodiphenylsulfoxide, 3,4'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfoxide, 1,3- Bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-ah Nophenyl) benzene, 1,4-bis (4-amino phenyl) benzene, 1,3-bis (4-aminophenoxy) benzene (or TPE-R), 1,4-bis (3-aminophenoxy) Benzene (or TPE-Q) 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3, 3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) benzene , 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4 -Aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4 ' -Bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, Bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- ( 4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy ) Phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] sulfide, bis [3- (4-aminophenoxy) phenyl] sulfide, Bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3-aminophenoxy) phenyl] sulfone, bis [3- ( 4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [3- (3-aminophenoxy ) Phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] propane, 2 , 2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 2,2-bis [3- (3 -Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] -1,1,1,3 , 3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane and 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane may include two or more components selected from the group consisting of.

In one specific example, the dianhydride monomer is pyromellitic dianhydride (or PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (or s-BPDA), 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3', 4 ' -Tetracarboxylic dianhydride (or DSDA), bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3 , 3,3-hexafluoropropane dianhydride, 2,3,3 ', 4'- benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dian Hydride (or BTDA), bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimelitic Monoester Acid Hydride), p-biphenylenebis (trimeric monoester acid anhydride), m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p-terphenyl- 3,4,3 ', 4'-tetracarboxylic dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxy Phenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2-bis [(3,4-dicarboxy phenoxy) phenyl] propane dianhydride Ride (BPADA), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride and 4,4 '-(2,2-hexafluoro It may include one or more components selected from the group consisting of isopropylidene) diphthalic acid dianhydride.

The monomers capable of implementing the first polyimide resin and / or the second polyimide resin may be components having a relatively rigid molecular structure, which is excellent in mechanical properties of the first polyimide resin and / or the second polyimide resin. Strength, such as good tensile strength and inherent modulus, can be directly related. As a result, the tensile strength and modulus of the core layer including the first polyimide resin and the polyimide composite film including the core layer may lead to being expressed at a desired level.

In one specific example, the diamine monomer may include two or more components selected from the group consisting of m-tolidine, O-tolidine, ODA and PPD, and more specifically m-tolidine and O- It may include one of tolidine and one or more components of ODA and PPD.

The benzidine structure possessed by m-tolidine and O-tolidine minimizes water penetration into the skin layer, water diffusion, and the like, and can mainly act to improve the moisture absorption rate of the polyimide composite film. In addition, the skin layer contains a fluorine-based resin that is classified as relatively hydrophobic, and as the second polyimide resin and the fluorine-based resin having such a benzidine structure exhibit a synergistic effect, moisture absorption through the skin layer is significantly suppressed. Can be.

Accordingly, the skin layer including the second polyimide resin and the fluorine-based resin may improve the moisture absorption rate that may adversely affect the dielectric properties and may advantageously be implemented in a desired aspect of the dielectric properties of the polyimide composite film.

In one specific example, the dianhydride monomer may have a relatively rigid molecular structure, and specifically include one or more components selected from the group consisting of PMDA, s-BPDA, a-BPDA and BTDA. It may be, and more specifically, may include two or more selected from the group consisting of PMDA, s-BPDA and a-BPDA.

The combination of monomers capable of implementing the core layer and / or skin layer of the present invention are components having a relatively rigid molecular structure, and the core layer and / or skin layer have excellent mechanical strength, such as excellent tensile strength and modulus. It can work to your advantage.

In addition, the first polyimide resin and / or the second polyimide resin prepared by the monomer combination has advantages related to low moisture absorption, but has dielectric properties that affect the electrical insulation properties of the polyimide composite film, such as low dielectric constant. Can be advantageously expressed.

The fluorine-based resin is at least one selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP) and ethylenetetrafluoroethylene (ETFE). It may include, in detail, it may be a polytetrafluoroethylene that is excellent in compatibility with the second polyimide resin and does not cause a decrease in adhesion.

The fluorine-based resin may be present in the skin layer in at least one state selected from:

(a) a first state physically bound to the polymer chain of the second polyimide resin; And

(b) Second state hydrogen-bonded to the polar group of the polymer chain of the second polyimide resin.

The fluorine-based resin present in the first state may be physically entangled in the polymer chain of the second polyimide resin, which may advantageously inhibit water penetration into the skin layer and / or diffusion of water within the skin layer.

The fluorine-based resin present in the second state is hydrogen bonded to a polar group in the polymer chain of the second polyimide resin, such as an imide group, and may provide advantages similar to the second state.

However, the fluorine-based resin present in a predetermined amount, while present in the first state and the second state, respectively, acts positively as described above, but when included in an excessive amount, deterioration of mechanical properties of the skin layer, in particular, tensile It can cause a significant decrease in strength and modulus, and can significantly decrease the surface properties of the produced film. The surface properties include, for example, thermal wrinkles. On the contrary, the skin layer containing too little fluorine-based resin is difficult to embed the above-mentioned advantages for moisture.

Therefore, while the above-mentioned advantages can be expressed, the content of the fluorine-based resin should be determined in a range in which there is no deterioration in the physical properties of the skin layer and further the polyimide composite film. Accordingly, in the present invention, the fluorine-based resin is added to the total weight of one skin layer. With respect to 10 to 60% by weight, specifically 20 to 50% by weight may be included.

When the skin layer includes a first skin layer formed on one surface of the core layer and a second skin layer formed on the other surface of the core layer, the first skin layer is 10 to 60% by weight relative to the total weight thereof, Specifically, 30 to 60% by weight, in particular 40 to 60% by weight of a fluorine-based resin, and the second skin layer is 10 to 60% by weight relative to its total weight, specifically 30 to 60% by weight , In particular, it may include 40 to 60% by weight of a fluorine-based resin.

Meanwhile, since the polyimide composite film according to the present invention is a multi-layered composite film composed of a skin layer and a core layer, the polyimide resins constituting each layer may each have a specific composition, and accordingly, the skin layer and the core layer may have any Desired physical properties can be inherent.

Specifically, the skin layer of the present invention may be directly related to the polyimide composite film having a low moisture absorption rate and a dielectric constant based on the second polyimide resin and fluorine resin constituting the same, and the core layer of the polyimide composite film While supporting the shape, it may be advantageous to meet various mechanical properties required for the insulating film.

As a contrasting example for comparison, a conventional polyimide monolayer film that does not include a skin layer and a core layer may include, for example, a fluorine-based resin.

Even if the polyimide monolayer film contains a fluorine-based resin for the purpose of suppressing moisture permeation, a large amount of fluorine-based resin may be present inside the polyimide film, for example, in the center of the film, and the concentration of the fluorine-based resin in the surface direction of the film from the center of the film A gradually decreasing concentration gradient may appear. Therefore, a conventional polyimide monolayer film has a limit to suppress the penetration of moisture through the surface even if it contains a fluorine-based resin.

For this reason, the polyimide monolayer film has been required to contain a relatively high content of a fluorine-based resin so that a large number of fluorine-based resins may be present on the surface of the film and adjacent portions thereof. However, since the fluorine-based resin can significantly degrade the mechanical properties of the polyimide film, the polyimide film can be expected to improve the moisture absorption rate at the expense of the mechanical properties.

In addition, since the single-layer polyimide film is composed of a single polyimide resin produced by any one monomer combination, not only the desired level of mechanical properties, but also the correlation with each other to the desired level of moisture absorption, dielectric constant, and thermal expansion coefficient Is difficult.

In summary, the polyimide composite film according to the present invention can be compatible with a variety of properties that are less related to each other based on its special structure, which is a specific effect in that it cannot be expressed in a conventional single-layer polyimide film. It can be recognized as.

In one specific example, the polyimide composite film may include a first skin layer having a skin layer formed on one surface of the core layer and a second skin layer formed on the other surface of the core layer,

The first skin layer contains 10 to 60% by weight of fluorine-based resin based on the total weight thereof, and the second skin layer contains 10 to 60% by weight of fluorine-based resin based on its total weight,

The ratio of the thickness of the core layer to the sum of the thicknesses of the first skin layer and the second skin layer (= core layer / (first skin layer + second skin layer)) is 1 to 5, specifically 1.5 to 4, more specifically, may be 2.0 to 3.0.

Each of the first skin layer and the second skin layer may be a single layer composed of one layer, and in some cases, may be formed in the form of a composite layer laminated with a plurality of unit layers bonded together.

The sum of the thicknesses of the first skin layer and the second skin layer and the thickness ratio of the core layer are particularly important when the mechanical properties of the polyimide composite film are maintained at a predetermined level, while the desired level of moisture absorption and dielectric properties are expressed. Can be.

Below the above range, when the entire first skin layer and the second skin layer are relatively thick and the core layer has a relatively thin structure, it is not preferable because the mechanical properties of the polyimide composite film may be significantly reduced.

Conversely, when the entire first skin layer and the second skin layer are excessively thin above the above range, the polymer chains of the second polyimide resin constituting the skin layer are excessively reduced to exclude the fluorine-based resin, thereby substantially reducing the It is difficult to form, and the structure can break even if layered.

The thickness of the first skin layer and the second skin layer may be the same or different from each other, and when different, 7: 3 to 3: 7 (first skin layer: second skin layer) except 5: 5 It can have a thickness ratio.

Based on the above advantages, the polyimide composite film according to the present invention may have a dielectric loss (Df) of 0.003 or less, a dielectric constant (Dk) of 3.2 or less, and a moisture absorption of 0.6% by weight or less.

Assuming when the polyimide composite film according to the present invention is used as the insulating film, particular attention should be paid to the dielectric constant, moisture absorption, and coefficient of thermal expansion among the above properties.

In general, the permittivity is an important characteristic value indicating the electrical properties of a dielectric (or insulator), that is, a nonconductor. The dielectric constant is not directly related to the electrical properties of DC current, but is directly related to the properties of AC current, especially AC electromagnetic waves. It is said to be.

In the insulator (for example, a polyimide film), + and-moment components, which are normally scattered in random directions, are aligned with changes in the electromagnetic field applied from the outside. That is, by changing the moment components in accordance with the changing direction of the electromagnetic field, it is possible to enable the propagation of electromagnetic waves inside the non-conductor yet on the other side.

The extent of how sensitively the moment inside the material reacts and moves to this change in the external electromagnetic field can be expressed as the dielectric constant.

Such dielectric constants allow an intuitive interpretation through relative permittivity, and the relative permittivity is air, which means the dielectric constant of each dielectric in proportion, and among them, imaginary numbers in the calculation of relative permittivity Excluded and expressed by mistake is the dielectric constant (Dk).

Since a high dielectric constant means that electrical energy is well transmitted, an insulator such as a polyimide film is preferable as the dielectric constant is lower.

Nevertheless, it has been already explained that the conventional polyimide film is not at a level sufficient to maintain sufficient insulation in high-frequency communication. This becomes evident when compared with the dielectric constant of liquid crystal polymers. In the case of liquid crystal polymers, the dielectric constant is known to be approximately 2.9 to 3.3, and most of them are superior to insulators compared to conventional polyimides having higher dielectric constants. can see.

On the other hand, the polyimide composite film according to the present invention is close to the dielectric constant of the liquid crystal polymer, or a lower dielectric constant, specifically, the dielectric constant may be 3.2 or less, in particular, 3.0 or less, and the lower limit may be 2.0 have. It can be seen that polyimide is an ideal form as an insulator when recalling that the engineering properties are at the highest level.

The meaning of the dielectric constant will be described in detail.

Even though all conductors are separated from each other, there is always capacitive coupling by an electric field, so even if the layers and layers of the multi-layer substrate are also electrically separated from each other, this is only an open circuit to DC. Can be seen as a capacitor with a value connected between them.

On the other hand, a capacitor has a property that an impedance decreases as a frequency of a current or a voltage across the capacitor increases, and the value can be expressed by the following equation.

-Impedance = 1 / (2 * π * f * C); Where f is the frequency and C = capacitance.

-C = e * S / d; Where e is the dielectric constant, S is the area of the conductor, and d is the distance.

In general, at a level that is visible and can be handled with bare hands, no matter how close the two conductors are, the capacitance value (farad) between them is difficult to escape from the pico unit. It is so small that the insulation between layers can be maintained even if the circuit is operating at a somewhat higher frequency.

On the other hand, in special cases, such as a communication device operating at a frequency of giga (GIGA) unit, for example, an ultra-high frequency of 2 GHz or more, since the frequency is very high as shown in the above formula, impedance may be lowered, so it may be difficult to maintain insulation.

Therefore, when selecting an insulator, it is necessary to minimize electrostatic coupling and capacitance (ie, impedance) by using a material having a low dielectric constant.

Accordingly, the polyimide film according to the present invention has a relatively low dielectric constant as described above, and thus it is easy to maintain insulation even in communication equipment operating at a frequency of giga (GIGA) unit, for example, ultra-high frequency of 2 GHz or more. There is this.

The moisture absorption rate is a rate indicating the amount of moisture the material is absorbing, and is generally known to increase the dielectric constant and dielectric loss rate when the moisture absorption rate is high.

Generally, when the water is in a solid state, the dielectric constant is 100 or more, when it is in the liquid state, it is about 80, and when it is in the gaseous state, it is known as 1.0059.

That is, water existing in a water vapor state other than the polyimide film does not substantially affect the dielectric constant and dielectric loss rate of the polyimide film. However, in a state in which water vapor or the like is absorbed by the polyimide film, water exists in a liquid state, and in this case, the dielectric constant and dielectric loss rate of the polyimide film may increase dramatically. In other words, the dielectric constant and dielectric loss rate of the polyimide film may change rapidly even with a small amount of moisture absorption.

Therefore, lowering the moisture absorption rate can be regarded as a very important factor for a polyimide film as an insulating film.

The polyimide composite film according to the present invention may have a moisture absorption rate of 1.0% by weight or less, specifically 0.7% by weight or less, and more specifically 0.6% by weight or less, and the achievement of the polyimide composite film of the present invention It is due to the constitutional characteristics. In summary, the polyimide composite film according to the present invention includes a fluorine-based resin in which the skin layer can inhibit the penetration of moisture, and includes benzidine, which is not water-friendly due to the polymer structure of the second polyimide resin. It is presumed to be due to the manifestation of a synergistic effect.

On the other hand, in order to suppress the occurrence of thermal distortion when the polyimide composite film is laminated with the metal foil for the implementation of the flexible metal foil-clad laminate, the thermal expansion coefficient of the polyimide film at 300 to 350 ° C is the same as the thermal expansion coefficient of the metal foil. Ideal. However, it is not practically easy to set the thermal expansion coefficient of the polyimide film to be the same as the metal foil, and in view of suppressing the occurrence of thermal distortion, the difference between the thermal expansion coefficient of the polyimide film and the thermal expansion coefficient of the metal foil is within ㅁ 10 ppm, detailed It is preferable to be within ㅁ 5 ppm.

However, when an adhesive layer having adhesiveness is formed between the polyimide film and the metal foil, the difference from the thermal expansion coefficient of the adhesive layer should also be considered.

Therefore, when the thermoplastic polyimide is used as the adhesive layer, the dimensional change can be minimized when the thermal expansion coefficient at 340 ° C of the polyimide film is 7 ppm / ° C or higher, and less, the dimensional change in the relationship with the metal foil and the adhesive layer Can appear excessively and cause bad appearance.

Also, in this case, the thermal expansion coefficient is preferably 15 ppm / ° C. or less, and when it exceeds this, the degree of expansion in the MD and TD directions is excessive, which may also cause poor appearance. A more preferable range for this may be a thermal expansion coefficient of 8 ppm / ° C or more to 15 ppm / ° C or less, particularly preferably 8 ppm / ° C or more to 3 ppm / ° C or less, and the polyimide composite film according to the present invention has a thermal expansion coefficient Is within the above preferred range, it can be expected that there is an advantage in the implementation of the flexible metal foil laminate.

Manufacturing method of polyimide composite film

Method for producing a polyimide composite film of the present invention,

Depositing a first composition comprising a first polyamic acid solution and a second composition comprising a second polyamic acid solution and a fluorine-based resin so as to be stacked adjacent to each other; And

And imidizing the film-formed first composition and second composition,

The polyimide composite film may include a core layer derived from the first composition and a skin layer derived from the second composition.

Each of the first polyamic acid solution and the second polyamic acid solution may include an organic solvent in which polyamic acid is soluble.

The organic solvent is not particularly limited as long as it is a solvent in which the polyamic acid can be dissolved, but as an example, the organic solvent may be an aprotic polar solvent.

As a non-limiting example of the aprotic polar solvent, amide solvents such as N, N'-dimethylformamide (DMF), N, N'-dimethylacetamide (DMAc), p-chlorophenol, o-chloro And phenol-based solvents such as phenol, N-methyl-pyrrolidone (NMP), gamma brotirolactone (GBL) and digrime, and these may be used alone or in combination of two or more.

In some cases, the solubility of the polyamic acid may be controlled by using auxiliary solvents such as toluene, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, ethanol, and water.

In one example, organic solvents that can be particularly preferably used in the preparation of the first polyamic acid solution and the second polyamic acid solution of the present invention are amide solvents N, N'-dimethylformamide and N, N'-dimethyl Acetamide.

The method of polymerizing the first polyamic acid solution and the second polyamic acid solution may be respectively prepared through the following methods:

(1) a method in which the total amount of the diamine monomer is placed in an organic solvent, and then the dianhydride monomer is added to be substantially equimolar with the diamine monomer and polymerized;

(2) a method in which the total amount of the dianhydride monomer is placed in an organic solvent, and then the diamine monomer is added to be substantially equimolar with the dianhydride monomer to polymerize;

(3) After adding some components of the diamine monomer in an organic solvent, after mixing some components of the dianhydride monomer with respect to the reaction component at a ratio of about 95 mol% to 105 mol%, the remaining diamine monomer components are added thereto. A method in which the remaining dianhydride monomer components are added successively to make the diamine monomer and the dianhydride monomer substantially equimolar;

(4) After placing the dianhydride monomer in an organic solvent, after mixing some components of the diamine compound with respect to the reaction component in a ratio of 95 mol% to 105 mol, other dianhydride monomer components are added and successively the remaining diamine A method of polymerization by adding a monomer component such that the diamine monomer and the dianhydride monomer become substantially equimolar; And

(5) Some diamine monomer components and some dianhydride monomer components are reacted so as to be in excess in one of the organic solvents to form a first polymer, and some diamine monomer components and some dianhydride monomer components are formed in another organic solvent. As a method for reacting such that one is in excess to form a second polymer, mixing the first and second polymers, and completing the polymerization, wherein the diamine monomer component is excessive when forming the first polymer. , In the second polymerized product, an excess of the dianhydride monomer component, and in the first polymerized product, if the dianhydride monomer component is excessive, in the second polymerized product, the diamine monomer component is added in excess, and the first and second polymerized products are mixed. All diamine monomer components and dianhydride monomer components used in these reactions are substantially equimolar. How to polymerize as possible.

However, the above method is an example for helping the implementation of the present invention, and the scope of the present invention is not limited to them, and it is of course possible to use any known method.

Each of the polyamic acid contained in the first polyamic acid solution and the second polyamic acid solution may have a weight average molecular weight of 150,000 g / mole or more to 1,000,000 g / mole or less, and more specifically, 260,000 g / mole or more to 700,000 g / mole It may be the following, and more specifically, may be 280,000 g / mole or more to 500,000 g / mole or less.

Polyamic acid having such a weight average molecular weight may be preferable for the production of a polyimide composite film having better heat resistance and mechanical properties.

In general, the weight average molecular weight of the polyamic acid can be proportional to the viscosity of the polyamic acid solution containing the polyamic acid and the organic solvent, and the weight average molecular weight of the polyamic acid can be controlled within the above range by adjusting the viscosity.

This is because the viscosity of the polyamic acid solution is proportional to the content of the polyamic acid solid content, in particular, the total amount of the dianhydride monomer and the diamine monomer used in the polymerization reaction. However, the weight average molecular weight does not represent a linear linear relationship with respect to viscosity, but is proportional to the logarithmic function.

That is, although the range in which the weight average molecular weight can be increased is limited while increasing the viscosity in order to obtain a higher weight average molecular weight polyamic acid, when the viscosity is too high, polya through a multi-layer die in the film forming process for coextrusion When discharging the mixed acid solution, it may cause a processability problem due to an increase in pressure inside the die.

Accordingly, each of the first polyamic acid solution and the second polyamic acid solution of the present invention may include 15% to 20% by weight of a polyamic acid solid content and 80% to 85% by weight of an organic solvent, in which case the viscosity is 90,000 It may be cP or more to 300,000 cP or less, specifically 100,000 cP or more to 250,000 cP. Within this viscosity range, the weight average molecular weight of the polyamic acid may fall within the above range, and the polyamic acid solution may not cause problems in the film forming process described above.

On the other hand, fillers may be added during the production of the first composition and the second composition for the purpose of improving various properties of the film such as sliding property, thermal conductivity, conductivity, corona resistance, and loop hardness of the polyimide composite film. The filler to be added is not particularly limited, and preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.

The average particle diameter of the filler is not particularly limited, and can be determined according to the characteristics of the polyimide composite film to be modified and the type of filler to be added. In one example, the average particle diameter of the filler may be 0.05 μm to 100 μm, specifically 0.1 μm to 75 μm, more preferably 0.1 μm to 50 μm, and particularly specifically 0.1 μm to 25 μm.

If the average particle diameter is less than this range, the modification effect is unlikely to appear, and if it exceeds this range, the filler may significantly impair the surface properties of the polyimide composite film or cause mechanical properties of the composite film to deteriorate.

In addition, the addition amount of the filler is not particularly limited, and can be determined by the characteristics of the polyimide film to be modified, the particle size of the filler, and the like.

In one example, the amount of the filler added is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight based on 100 parts by weight of the polyamic acid solution.

When the amount of the filler added is less than this range, the modification effect by the filler is unlikely to appear, and when it exceeds this range, the mechanical properties of the polyimide film may be greatly deteriorated. The method for adding the filler is not particularly limited, and any known method can be used.

In one specific example, the step of forming the film is co-extruded on a support so as to be laminated in the order of the second composition, the first composition and the second composition, and the coextruded first composition and the second composition are 50 ° C to It may include the step of heat treatment in a temperature range of 200 ℃.

In another specific example, the step of forming the film is co-extruded on a support so as to be laminated in the order of the first composition and the second composition, and the temperature of the co-extruded first composition and the second composition is 50 ° C to 200 ° C. It may include a step of heat treatment in the range.

When the precursor composition is heat-treated as described above, the precursor composition may be converted into a form having self-support in an intermediate step with respect to conversion from polyamic acid to polyimide.

In some cases, after adjusting the thickness and size of the polyimide composite film and improving the orientation, a process of stretching the heat-treated precursor composition may be performed, and the stretching may be performed in a machine conveying direction (MD) and It may be performed in at least one of the transverse direction (TD) with respect to the machine transport direction.

Thereafter, by proceeding the imidization step, at least 90 mol%, more specifically 95 mol% or more, more specifically 98 mol% or more, and particularly 99 mol% or more of the amic acid group constituting the polyamic acid is an imide group. Converting to produce a polyimide composite film. The imidization step may include heat-treating the first composition and the second composition in a heat-treated state to a temperature of 200 ° C to 700 ° C again.

Here, imidization refers to a phenomenon, process, or method in which the amic acid group is converted to an imide group by inducing a ring-closure and dehydration reaction of an amic acid group forming a polyamic acid through heat and / or a catalyst.

The imidization method may be performed through a thermal imidization method, a chemical imidization method, or a complex imidization method using a combination of the thermal imidization method and a chemical imidization method.

The thermal imidization method may be a method of excluding chemical catalysts and performing heat treatment at a temperature of 200 ° C to 700 ° C using a heat source such as hot air or an infrared dryer.

In some cases, the polyimide composite film obtained as described above may be heated to a temperature of 400 ° C to 700 ° C for 5 seconds to 400 seconds to further harden the polyimide composite film, and may remain in the obtained polyimide composite film. This may be done under a given tension to relieve any internal stresses that may be present.

The chemical imidization method is a method of promoting imidization of an amic acid group in the imidization process by adding a dehydrating agent and / or an imidizing agent to each of the first composition and the second composition.

Here, the term “dehydrating agent” refers to a substance that promotes a cyclization reaction through dehydration of a polyamic acid, and includes, without limitation, aliphatic acid anhydrides, aromatic acid anhydrides, N, N'- Dialkyl carbodiimide, halogenated lower aliphatic, halogenated lower patty acid anhydride, aryl phosphonic dihalide, thionyl halide, and the like. Of these, aliphatic acid anhydrides may be preferred from the viewpoint of ease of availability and cost, and non-limiting examples include acetic anhydride (AA), propionic acid anhydride, and lactic acid anhydride. Etc. are mentioned, These can be used individually or in mixture of 2 or more types.

In addition, "imide agent" means a substance having an effect of promoting a ring-closure reaction to polyamic acid, and may be, for example, imine-based components such as aliphatic tertiary amine, aromatic tertiary amine, and heterocyclic tertiary amine. . Of these, heterocyclic tertiary amines may be preferable from the viewpoint of reactivity as a catalyst. Non-limiting examples of heterocyclic tertiary amines include quinoline, isoquinoline, β-picoline (BP), pyridine and the like, and these may be used alone or in combination of two or more.

In each of the first composition and the second composition, the amount of the dehydrating agent added is preferably in the range of 0.5 to 5 moles, and particularly preferably in the range of 1.0 to 4 moles, per 1 mole of the amic acid group in the polyamic acid contained in the composition. . In addition, in each of the first composition and the second composition, the amount of the imidizing agent added is preferably in the range of 0.05 mol to 2 mol with respect to 1 mol of the amic acid group in the polyamic acid contained in the composition, and in the range of 0.2 mol to 1 mol It may be particularly desirable to be scented.

When the dehydrating agent and the imidizing agent fall below the above range, chemical imidization is insufficient, cracks may be formed in the polyimide composite film to be produced, and mechanical strength of the composite film may also be lowered. In addition, if these addition amounts exceed the above range, imidization may proceed excessively rapidly, and in this case, it may be difficult to cast in the form of a multi-layer film, or the produced polyimide composite film may exhibit brittle characteristics. It is not desirable.

The composite imidization method may be to perform a thermal imidization method in addition to the above chemical imidization method.

Ductile metal laminate

The present invention provides a flexible metal foil-clad laminate comprising the polyimide composite film described in the previous embodiment.

In the flexible metal foil-clad laminate of the present invention, a metal foil is laminated to the skin layer of the polyimide composite film, or an adhesive layer containing a thermoplastic polyimide is added to the skin layer of the polyimide composite film, and the metal foil is attached to the adhesive layer. It may be a laminated structure in the state.

The metal foil is not particularly limited, and may be, for example, copper, copper alloy, stainless steel, stainless steel alloy, nickel, nickel alloy, aluminum or aluminum alloy. In addition, an anti-rust layer, a heat-resistant layer, or an adhesive layer may be coated on the surface of the metal foil.

The thickness of the metal foil may be a thickness capable of exerting a sufficient function depending on its use, and as a non-limiting example to aid implementation, the thickness of the metal foil may be 0.1 μm to 1000 μm.

The adhesive may be a thermoplastic polyimide-based material such as a thermoplastic polyimide thermoplastic polyamideimide, a thermoplastic polyetherimide, and a thermoplastic polyesterimide, which may be preferred in terms of dimensional stability with a polyimide composite film. This is an example to aid implementation, and is not limited thereto.

The flexible metal foil-clad laminate according to the present invention can be produced by a thermal lamination method of bonding a metal foil to a polyimide composite film as a base film.

The method allows, for example, to continuously pass a base film and a metal foil ('coated body') to a roll laminate device including two or more metal heating rolls, and the heat and pressure applied in the process may It may include a process of thermal lamination of the laminate.

When performing the thermal lamination, a protective material may be disposed between the heating roll and the object to be laminated, in particular between the heating roll and the metal foil, in order to improve the appearance of the obtained flexible metal foil-clad laminate.

The protective material is not particularly limited as long as it is a material that can withstand the heating temperature of the thermal laminate, but may be a heat-resistant plastic such as non-thermoplastic polyimide, or a metal foil such as copper foil, aluminum foil, stainless steel foil. Among them, a non-thermoplastic polyimide having excellent heat resistance and reusability may be preferable.

When the thickness of the protective material is excessively thin, when heat-laminating, the role of cushioning and protection may be insufficient, and the thickness of the protective material may be at least 70 μm, in particular, 75 μm or more.

Further, the protective material may be one layer, but in some cases, it may be used in a multi-layered form of two or more layers.

On the other hand, it should be noted that, since the heating temperature required for thermal lamination is quite high, if a protective material having a temperature close to room temperature is used as it is for thermal lamination, the appearance or dimensional stability of the flexible metal foil laminate obtained by its rapid thermal expansion is poor. May not.

This allows preheating of the protective material prior to the thermal lamination process. As described above, if the thermal lamination process is performed after the preliminary heating of the protective material, thermal expansion of the protective material can be terminated, thereby preventing abnormal damage.

The heating method of the layered object in the thermal laminate is not particularly limited, and for example, a heating means capable of heating to a predetermined temperature, such as a thermal circulation method, a hot air heating method, or an induction heating method, may be used. Similarly, the method of pressing the layered object in the thermal laminate is not particularly limited, and for example, a method capable of applying a predetermined pressure, such as a hydraulic method, an air pressure method, and a gap-to-gap pressure method, may be selected and used.

In the thermal laminate, the heating temperature, that is, the laminate temperature may be + 50 ° C or higher of the polyimide film glass transition temperature (T _g ) of the base film, and more specifically, to increase the lamination rate, the polyimide film glass transition It may be more than +100 ℃ of the temperature (T _g ).

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

Preparation Example 1: Preparation of core layer (first composition)

After sequentially dissolving 197.9 kg of DMF, 16.06 kg of m-tolidine, 1.89 kg of ODA, and 1.02 kg of PPD in a 300 L reactor at 25 ° C. and a nitrogen atmosphere, reacted 11.12 kg of BPDA, 11.78 kg of PMDA, and 0.56 kg of PMDA. The viscosity was adjusted while introducing to obtain a first composition comprising a first polyamic acid solution having a viscosity of about 110,000 cP.

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

After adding DMF 221.0 kg into a 300 L reactor under a 25 ° C. and nitrogen atmosphere, 9.05 kg of m-tolidine, 1.6 kg of ODA, and 0.29 kg of PPD were sequentially dissolved, followed by reacting 9.4 kg of BPDA and 4.3 kg of PMDA, and then 0.12 kg of PMDA. While adjusting the viscosity to obtain a second polyamic acid solution having a viscosity of about 50,000 cP, 41.7 kg of Mitsubishi Pencil's 40% PTFE solution was added thereto to obtain a second composition having a viscosity of about 30,000 cP. Obtained.

<Example 1>

The first composition prepared in Preparation Example 1 is introduced into the first storage tank 101 of the coextrusion die 100 having the structure shown in FIG. 1, and the second prepared storage tank 102 is manufactured in Preparation Example 2 2 The composition was added.

Thereafter, the second composition, the first composition, and the second composition were coextruded on the endless belt 105 to form a precursor composition with a thickness of about 25 micrometers. At this time, when the first composition was extruded from the first storage tank 101, a mixture of isoquinoline, dimethylformamide and acetic anhydride was mixed from the catalyst storage tank 103.

Subsequently, heat treatment was performed at a temperature of about 150 ° C., which was again heated from 150 ° C. to 600 ° C. in a high-temperature tenter, and then cooled at 25 ° C. to obtain a polyimide composite film having a skin layer / core layer / skin layer structure. The content of the second polyamic acid and the PTFE solid content for preparing the core layer, the thickness of the polyimide composite film (core layer / skin layer), and the ratio thereof are shown in Table 1 below.

<Examples 2 to 4>

By controlling the mixing ratio of the second polyamic acid solution and the PTFE solution in Preparation Example 2, the contents of the second polyamic acid solid content and the PTFE solid content in the second composition are changed as described in Table 1 below, and / or the polyimide composite film A polyimide composite film was prepared in the same manner as in Example 1, except that the extrusion amount of the coextruder was controlled to have the ratio of the thickness and the thickness of the core layer and the skin layer as shown in Table 1 below.

<Comparative Example 1>

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

<Comparative Examples 2 to 4>

By controlling the mixing ratio of the second polyamic acid solution and the PTFE solution in Preparation Example 2, the contents of the second polyamic acid solid content and the PTFE solid content in the second composition are changed as described in Table 1 below, and / or the polyimide composite film A polyimide composite film was prepared in the same manner as in Example 1, except that the extrusion amount of the coextruder was controlled to have the ratio of the thickness and the thickness of the core layer and the skin layer as shown in Table 1 below.

<Comparative Example 5>

A precursor composition obtained by mixing isoquinoline, dimethylformamide and acetic anhydride as a catalyst was applied to the second composition prepared in Preparation Example 2 on a SUS plate. Then, heat treatment was performed in a temperature range 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 polyimide film.

Second polyamic acid
Solid content
(weight%) PTFE
Solid content
(weight%) PI composite film thickness
(㎛) Core layer thickness
(㎛) Skin layer thickness *
(㎛) Thickness Ratio ** Example 1 60 40 25 17 8 2.13 Example 2 50 50 25 17 8 2.13 Example 3 70 30 25 17 8 2.13 Example 4 40 60 25 17 8 2.13 Comparative Example 1 100 0 25 25 - - Comparative Example 2 35 65 25 17 8 2.13 Comparative Example 3 60 40 24 8 16 0.50 Comparative Example 4 60 40 25 21 4 5.25 Comparative Example 5 60 40 25 - - -

* First skin layer thickness + second skin layer thickness

** Core layer thickness / (first skin layer thickness + second skin layer thickness)

<Experimental Example: Characteristic evaluation of polyimide film>

For the evaluation of the properties of the polyimide composite films prepared in Examples 1 to 4 and Comparative Examples 1 to 5, respectively, the dielectric constant, dielectric loss, moisture absorption, film forming property and elongation were measured using the following methods, and the results were It is shown in Table 2 below.

-Dielectric constant and dielectric loss : The dielectric constant and dielectric loss were measured by connecting the E5063A to SPDR (10GHz).

-Hygroscopicity: After absorbing water for 24 hours according to the ASTM D570 analysis method, the moisture absorption rate was evaluated by measuring the weight before and after treatment.

-Film forming property : It was observed with the naked eye.

- Elongation at break was measured according to the ASTM D 882 method measured using an Instron (Instron 3365SER) equipment.

permittivity Dielectric loss Moisture absorption rate
(%) Filmmaking * Elongation
(%) Example 1 3.04 0.0028 0.5 Good 44 Example 2 3.01 0.0027 0.5 Good 42 Example 3 3.08 0.0029 0.4 Good 45 Example 4 2.98 0.0025 0.6 Good 40 Comparative Example 1 3.4 0.0035 1.0 Good 50 Comparative Example 2 2.86 0.0025 0.3 Bad 34 Comparative Example 3 2.83 0.0025 0.3 Bad 34 Comparative Example 4 3.22 0.0032 0.8 Good 47 Comparative Example 5 2.8 0.0025 0.3 Bad 20

From the results in Table 2, the Examples exhibited performance in compliance with all of the dielectric constant, dielectric constant, moisture absorption, film forming properties and elongation. On the other hand, it can be seen that Comparative Examples 1 to 4 have at least one of these characteristics defective.

On the other hand, in Comparative Example 2, which included an excess of PTFE outside the scope of the present invention, a gel film having a self-supporting property was not well formed, and the appearance of wrinkles or cracks was very poor, which was not applicable to a thin circuit board. Was confirmed.

In addition, it can be seen that, in the case of Comparative Example 5, the elongation is remarkably poor, which is advantageous as a film of a flexible metal foil-clad laminate compared to a single-layer film in which the composite film in which the skin layer and the core layer are combined has only a skin layer structure as in the present invention. Disprove that it can be utilized.

Although described above with reference to embodiments of the present invention, those of ordinary skill in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above.

Claims (18)

A core layer comprising a first polyimide resin; And
A second polyimide resin and a fluorine-based resin, and at least one skin layer formed in a state bonded to at least one surface of the core layer,
The skin layer contains 60% by weight or less of a fluorine-based resin based on the total weight thereof,
A polyimide composite film having a dielectric loss (Df) of 0.003 or less, a dielectric constant (Dk) of 3.2 or less, and a moisture absorption rate of 0.6% by weight or less. According to claim 1,
The first polyimide resin and the second polyimide resin are each prepared by polymerization of a diamine monomer and a dianhydride monomer, a polyimide composite film. According to claim 2,
The diamine monomer,
1,4-diaminobenzene (or paraphenylenediamine, PDA, PPD), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzo Diaminodiphenyl ethers, such as diacid (or DABA), 4,4'-diaminodiphenyl ether (or oxidianiline, ODA), 3,4'-diaminodiphenyl ether, 4,4'-dia Minodiphenylmethane (or 4,4'-methylenediamine, MDA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl , 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy- 4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4'-dia Minobenzanilide, 3,3'-dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dime Thoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4,4'-dia Minodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4, 4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diamino Diphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) Propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3 , 3,3-hexafluoropropane, 3,3'-diaminodiphenylsulfoxide, 3,4'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfoxide, 1,3- Bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-ah Nophenyl) benzene, 1,4-bis (4-amino phenyl) benzene, 1,3-bis (4-aminophenoxy) benzene (or TPE-R), 1,4-bis (3-aminophenoxy) Benzene (or TPE-Q) 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3, 3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) benzene , 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4 -Aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4 ' -Bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, Bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- ( 4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy ) Phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] sulfide, bis [3- (4-aminophenoxy) phenyl] sulfide, Bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3-aminophenoxy) phenyl] sulfone, bis [3- ( 4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [3- (3-aminophenoxy ) Phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] propane, 2 , 2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 2,2-bis [3- (3 -Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] -1,1,1,3 , 3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane and 2,2-bis [4- (4-aminophenoxy) phenyl] A polyimide composite film comprising two or more components selected from the group consisting of -1,1,1,3,3,3-hexafluoropropane. According to claim 1,
The dianhydride monomer is pyromellitic dianhydride (or PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (or s-BPDA), 2,3,3' , 4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3 ', 4'-tetracarboxylic dian Hydride (or DSDA), bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexa Fluoropropane dianhydride, 2,3,3 ', 4'- benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (or BTDA) , Bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimeric monoester acid anhydride ), p-bipe Renbis (trimeric monoester acid anhydride), m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3', 4 '-Tetracarboxylic dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2-bis [(3,4-dicarboxy phenoxy) phenyl] propane dianhydride (BPADA), 2,3 , 6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride and 4,4 '-(2,2-hexafluoroisopropylidene) diphthalic acid dianhydride A polyimide composite film comprising at least one component selected from the group consisting of rides. According to claim 1,
The fluorine-based resin is at least one selected from the group consisting of polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), fluorinated (fluorinated) ethylene propylene (FEP) and ethylene tetrafluoroethylene (ETFE) The polyimide composite film containing. The method of claim 5,
The polyimide composite film, wherein the fluorine-based resin is polytetrafluoroethylene. According to claim 1,
The skin layer includes a first skin layer formed on one surface of the core layer and a second skin layer formed on the other surface of the core layer,
The first skin layer contains 10 to 60% by weight of a fluorine-based resin based on the total weight of the first skin layer,
The second skin layer contains 10 to 60% by weight of a fluorine-based resin based on the total weight thereof,
The ratio of the thickness of the core layer to the sum of the thicknesses of the first skin layer and the second skin layer (= core layer / (first skin layer + second skin layer)) is 1 to 5, polyimide composite film . According to claim 1,
A polyimide composite film having an elongation of 30% or more. According to claim 1,
The polyimide composite film having a thickness of 10 to 100 μm of the polyimide composite film. According to claim 1,
The polyimide composite film, wherein the fluorine-based resin is present in at least one state selected from:
A first state physically bound to the polymer chain of the second polyimide resin; And
Second state hydrogen-bonded to the polar group of the polymer chain of the second polyimide resin. A method for manufacturing the polyimide composite film according to claim 1,
Depositing a first composition comprising a first polyamic acid solution and a second composition comprising a second polyamic acid solution and a fluorine-based resin so as to be stacked adjacent to each other; And
And imidizing the film-formed first composition and second composition,
The polyimide composite film comprises a core layer derived from the first composition and a skin layer derived from the second composition. The method of claim 11,
The film forming step is a step of co-extrusion on a support so as to be laminated in the order of the second composition, the first composition and the second composition, and the coextruded first composition and the second composition in a temperature range of 50 ° C to 200 ° C. Manufacturing method comprising the step of heat treatment. The method of claim 11,
The film forming step comprises co-extruding on a support so as to be laminated in the order of the first composition and the second composition, and heat treating the coextruded first composition and the second composition in a temperature range of 50 ° C to 200 ° C. The manufacturing method comprising. The method of claim 11,
The imidizing step comprises a step of heat treatment to a temperature of 200 ℃ to 700 ℃, the manufacturing method. A flexible metal foil laminate comprising the polyimide composite film according to claim 1. The method of claim 15,
A metal foil is laminated to the skin layer of the polyimide composite film, or an adhesive layer containing a thermoplastic polyimide is added to the skin layer of the polyimide composite film, and the metal foil is laminated while attached to the adhesive layer, Flexible metal laminate. An electronic component comprising the flexible metal foil laminate according to claim 15 as an electrical signal transmission circuit. The electronic component according to claim 17, wherein the electrical signal transmission circuit transmits a signal at a high frequency of at least 2 GHz.

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