KR102682572B1 - Multilayer polyimide film and manufacturing method of the same - Google Patents

Abstract

The present invention includes at least one skin layer formed on at least one outer surface of the core layer, has a dielectric loss factor of 0.003 or less, an adhesive force of 1,000 gf/cm or more, and a storage modulus at 300°C of 1,000 MPa or more. Provided is a multilayer polyimide film and a method for manufacturing the same.

Description

Multilayer polyimide film and manufacturing method thereof {MULTILAYER POLYIMIDE FILM AND MANUFACTURING METHOD OF THE SAME}

The present invention relates to a multilayer polyimide film having excellent low dielectric strength, adhesive strength, and high-temperature storage modulus properties, and a method for manufacturing the same.

Polyimide (PI) is a polymer that has the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials, based on an imide ring with a rigid aromatic main chain and excellent chemical stability. It's a material.

In addition, due to its excellent electrical properties such as insulation properties and low dielectric constant, it is attracting attention as a highly functional polymer material in microelectronics, optical fields, etc.

Taking the field of microelectronics as an example, due to the weight reduction and miniaturization of electronic products, highly integrated and flexible thin circuit boards are being actively developed. These thin circuit boards have excellent heat resistance, low temperature resistance, and insulation characteristics while being easy to bend. A structure in which a circuit including a metal foil is formed on a polyimide film is being widely used. This thin circuit board is sometimes referred to as a flexible metal clad laminate in a broad sense, and as an example of this, when a thin copper plate is used as a metal foil, it is also referred to as a flexible copper clad laminate (FCCL) in a narrow sense. In addition, polyimide is also used as a protective film and insulating film for thin circuit boards.

Methods for manufacturing flexible metal clad laminates include, for example, (i) casting or applying polyamic acid, a precursor of polyimide, onto metal foil and then imidizing it, (ii) sputtering or plating. Examples include a metallizing method of installing a metal layer directly on a polyimide film, and (iii) a laminating method of bonding a polyimide film and metal foil through thermoplastic polyimide using heat and pressure.

The double lamination method is advantageous 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 metallizing method. As a device for performing lamination, a roll lamination device or a double belt press device that laminates continuously while feeding roll-shaped materials is used. Among the above, from the viewpoint of productivity, the thermal roll laminating method using a thermal roll laminating device can be used more preferably.

However, in the case of laminate, as mentioned above, since a thermoplastic resin is used for adhesion between the polyimide film and the metal foil, the glass transition of the polyimide film must exceed 300°C in some cases in order to develop the heat-sealability of the thermoplastic resin. It is necessary to apply heat of 400°C or more, which is close to or higher than the temperature (Tg), to the polyimide film.

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

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

Another thing to note is that the glass transition temperature of the polyimide film is significantly lower than the temperature at the time of lamination. Specifically, since the viscosity of the polyimide film is relatively high at the temperature at which lamination is performed, a relatively large dimensional change may occur, and accordingly, there is a risk that the appearance quality of the polyimide film may deteriorate after lamination.

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

Meanwhile, as various functions are recently incorporated into electronic devices, fast calculation and communication speeds are required for these electronic devices. To meet these requirements, thin circuit boards capable of high-speed communication transmission with low dielectric loss even at high frequencies of 10 GHz or higher have been developed. there is.

In order to realize high-frequency, high-speed communication, an insulator with high impedance that can maintain electrical insulation even at high frequencies is required.

Impedance is inversely proportional to the frequency and dielectric constant (Dk) formed in the insulator, so in order to maintain insulation even at high frequencies, the dielectric constant must be as low as possible.

However, in the case of typical polyimide, the dielectric constant is around 3.4 to 3.6, which is not excellent enough to maintain sufficient insulation in high-frequency communication. For example, in thin circuit boards where high-frequency communication of 10 GHz or higher is performed, insulation is partially or partially lost. There is a possibility of total loss.

In addition, it is known that the lower the dielectric constant of the insulator, the lower the occurrence of undesirable stray capacitance and noise in thin circuit boards, thereby eliminating many of the causes of communication delays. Polyimide Keeping the dielectric constant as low as possible is recognized as the most important factor in the performance of thin circuit boards.

Another thing to note is that in the case of high-frequency communication above 10 GHz, dielectric loss inevitably occurs through polyimide.

The dielectric dissipation factor (Df) refers to the degree of electrical energy wasted in a thin circuit board and is closely related to the signal transmission delay that determines the communication speed, so keeping the dielectric dissipation factor of polyimide as low as possible is also important for thin circuit boards. It is recognized as an important factor in the performance of the board.

Therefore, there is a need to develop a polyimide film that has a relatively low dielectric loss rate and high adhesion and high temperature storage elastic modulus, enabling stable circuit implementation, and an effective manufacturing method thereof.

The matters described in the above background technology are intended to aid understanding of the background of the invention, and may include matters that are not prior art already known to those skilled in the art in the field to which this technology belongs.

Republic of Korea Patent Publication No. 10-2012-0133807

The purpose of one aspect of the present invention is to provide a multilayer polyimide film with excellent adhesion, relatively low dielectric loss, and high high-temperature storage modulus, and an effective manufacturing method thereof, specifically, types of dianhydride and diamine. By determining the types and mixing ratios of polyimide resins and composing polyimide resins of different compositions in multiple layers, a polyimide film has excellent adhesion, low dielectric loss even at high frequencies, and excellent high-temperature storage modulus properties. is to provide.

Another object of the present invention is to provide a flexible copper-clad laminate that is effective for high-speed transmission and communication at high frequencies, including a multilayer polyimide film with excellent adhesion, relatively low dielectric loss rate, and excellent high-temperature storage modulus characteristics. It is provided.

Accordingly, the practical purpose of the present invention is to provide specific examples thereof.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

One aspect of the present invention for achieving the above object includes at least one skin layer formed on at least one outer surface of the core layer,

Dielectric loss factor is less than 0.003, adhesion is more than 1,000 gf/cm,

A storage modulus at 300°C of 1,000 MPa or more,

A multilayer polyimide film is provided.

Another aspect of the present invention includes the multilayer polyimide film and an electrically conductive metal foil,

Provided is a flexible metal foil laminate.

Another aspect of the present invention includes the flexible metal foil laminate,

Provides electronic components.

The present invention provides a polyimide film in which the composition ratio and reaction ratio of dianhydride and diamine components are adjusted, thereby providing a polyimide film with excellent low dielectric strength, adhesive strength, and high-temperature storage modulus properties.

Another object of the present invention is to provide a flexible copper-clad laminate that is effective for high-speed transmission and communication at high frequencies, including a multilayer polyimide film with excellent adhesion, relatively low dielectric loss rate, and excellent high-temperature storage modulus characteristics. It is provided.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

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

In this specification, singular expressions include plural expressions, unless the context clearly dictates otherwise. In this specification, terms such as “comprise,” “comprise,” or “have” are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and are intended to indicate the presence of one or more other features or It should be understood that this does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

As used herein, “dianhydride acid” is intended to include precursors or derivatives thereof, which may not technically be dianhydride acids, but which will nonetheless react with diamines to form polyamic acids, which in turn will form polyamic acids. It can be converted to mead.

As used herein, “diamine” is intended to include precursors or derivatives thereof, which may not technically be diamines, but which will nonetheless react with dianhydride to form polyamic acids, which in turn will form polyamic acids. Can be converted to mead

When amounts, concentrations, or other values or parameters are given herein as ranges, preferred ranges, or enumerations of upper preferred values and lower preferred values, any pair of upper range limits or It is to be understood that the preferred values and any lower range limits or all ranges formed from the preferred values are specifically disclosed.

When a range of numerical values is stated herein, unless otherwise stated, the range is intended to include the endpoints and all integers and fractions within the range. The scope of the invention is not intended to be limited to the specific values recited when defining the scope.

The multilayer polyimide film according to one embodiment of the present invention includes at least one skin layer formed on at least one outer surface of the core layer, has a dielectric loss factor of 0.003 or less, an adhesive force of 1,000 gf/cm or more, and a thickness of 300 gf/cm. The storage modulus at ℃ may be 1,000 MPa or more.

In one embodiment, it may have a three-layer structure including the skin layer formed on one outer surface of the core layer and an opposite surface of the outer surface.

The dianhydride and diamine components and their composition ratios of the skin layer formed on one outer surface of the core layer and the opposite surface of the outer surface may be the same or different.

Additionally, the thickness of the skin layer formed on one outer surface of the core layer and the opposite surface of the outer surface may be the same or different.

In one embodiment, the total thickness of the three-layer polyimide film is 10 μm or more and 100 μm or less, and the thickness of the core layer is 70% or more and 95% or less of the total thickness of the multilayer polyimide film. , the sum of the thicknesses of the skin layers formed on one outer surface of the core layer and the opposite surface of the outer surface may be 5% or more and 30% or less of the total thickness of the multilayer polyimide film.

As an example, the core layer may have a thickness of 41 μm or more and 50 μm or less, and the thickness of the skin layer may be 1 μm or more and 4 μm or less.

The thickness of the core layer may be, for example, 41 μm or more, 42 μm or more, 43 μm or more, 44 μm or more, 45 μm or more, 46 μm or more, 47 μm or more, or 48 μm or more.

If the thickness of the core layer and/or skin layer is above or below the above range, the adhesive force or high-temperature storage modulus characteristics of the multilayer polyimide film may be reduced.

In one embodiment, the core layer includes a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA), paraphenylene diamine (PPD), and m- It can be obtained by imidizing a polyamic acid solution containing a diamine component including tolidine (m-tolidine).

In addition, the skin layer includes a dianhydride component including biphenyltetracarboxylic dianhydride and p-phenylenebis(trimellitate anhydride) (TAHQ), and m-tolidine. It can be obtained by subjecting a polyamic acid solution containing a diamine component to an imidization reaction.

In one embodiment, in the core layer, the content of the biphenyltetracarboxylic dianhydride is 50 mol% to 70 mol% based on the total content of the dianhydride component of 100 mol%, and the pyromellitic The content of dianhydride is 30 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 60 mol% or more and 80 mol% or less, based on a total content of 100 mol% of the diamine component, and the m -The content of tolidine may be 20 mol% or more and 40 mol% or less.

In one embodiment, the core layer may include a block copolymer including two or more blocks.

The block copolymer of the core layer includes a first block containing 40 mol% or more and 50 mol% or less of the pyromellitic dianhydride based on 100 mol% of the total content of the dianhydride component of the polyimide film. And, it may include a second block containing 30 mol% or more and 40 mol% or less of m-tolidine based on 100 mol% of the total content of the diamine component of the polyimide film.

The first block can be obtained by imidating pyromellitic dianhydride and paraphenylene diamine, and the second block can be obtained by imidizing m-tolidine and biphenyltetracarboxylic dianhydride. You can.

In addition, all of the pyromellitic dianhydride of the first block may be imidized with paraphenylene diamine, and all of the m-tolidine of the second block may be imidized with biphenyltetracarboxylic dianhydride. You can.

Additionally, the skin layer may also include a block copolymer containing two or more blocks.

In one embodiment, in the skin layer, based on 100 mol% of the total content of the dianhydride component, the content of the biphenyltetracarboxylic dianhydride is 40 mol% to 60 mol%, and the p-phenyl The content of lenbis (trimellitate anhydride) may be 40 mol% or more and 60 mol% or less, and the content of m-tolidine may be 100 mol% based on a total content of 100 mol% of the diamine component.

Paraphenylene diamine of the present invention is a rigid monomer, and as the content of paraphenylene diamine increases, the polyimide synthesized has a more linear structure, contributing to the improvement of the mechanical properties of the polyimide.

also. m-tolidine has a particularly hydrophobic methyl group, contributing to the low moisture absorption properties associated with the dimensional stability of polyimide films against moisture.

The polyimide chain derived from biphenyltetracarboxylic dianhydride of the present invention has a structure named charge transfer complex (CTC), that is, an electron donor and an electron acceptor. They have regular straight structures located close to each other, and intermolecular interactions are strengthened.

Since this structure has the effect of preventing hydrogen bonding with moisture, it can maximize the effect of lowering the hygroscopicity of the polyimide film, which affects dimensional stability against moisture by lowering the moisture absorption rate.

In addition, pyromellitic dianhydride is a dianhydride component with a relatively rigid structure and is preferable because it can provide appropriate elasticity to the polyimide film.

In order for a polyimide film to have excellent dimensional stability, the content ratio of dianhydride is important. For example, as the content ratio of biphenyltetracarboxylic dianhydride decreases, it becomes difficult to expect a low moisture absorption rate due to the CTC structure, and dimensional stability against moisture also decreases.

In addition, biphenyltetracarboxylic dianhydride contains two benzene rings corresponding to the aromatic moiety, while pyromellitic dianhydride contains one benzene ring corresponding to the aromatic moiety.

The increase in the content of pyromellitic dianhydride in the dianhydride component can be understood as an increase in the imide group within the molecule based on the same molecular weight, which means that the imide group derived from the pyromellitic dianhydride is added to the polyimide polymer chain. It can be understood that the ratio of the group increases relative to the imide group derived from biphenyltetracarboxylic dianhydride.

In other words, the increase in pyromellitic dianhydride content can be seen as a relative increase in imide groups in the entire polyimide film, which makes it difficult to expect high dimensional stability against moisture due to low moisture absorption.

Conversely, when the content ratio of pyromellitic dianhydride is reduced, the component with a relatively rigid structure is reduced, and the elasticity of the polyimide film may be lowered below a desired level.

For this reason, when the content of the biphenyltetracarboxylic dianhydride exceeds the above range or the content of pyromellitic dianhydride is below the above range, the dimensional stability of the polyimide film may be reduced.

Conversely, even if the content of the biphenyltetracarboxylic dianhydride is below the above range or the content of the pyromellitic dianhydride is above the above range, the dimensional stability of the polyimide film may be adversely affected. .

In the present invention, the production of polyamic acid is, for example,

(1) A method of polymerizing the entire amount of the diamine component in a solvent, and then adding the dianhydride component in substantially equimolar amounts to the diamine component;

(2) A method of polymerizing the entire amount of the dianhydride component in a solvent, and then adding the diamine component in substantially equimolar amounts to the dianhydride component;

(3) After adding some of the diamine components into the solvent, mixing some of the dianhydride components in a ratio of about 95 to 105 mol% with respect to the reaction components, adding the remaining diamine components, and then adding the remaining dianhydride components continuously. A method of polymerizing by adding components such that the diamine component and the dianhydride component are substantially equimolar;

(4) After adding the dianhydride component into the solvent, mixing some components of the diamine compound in a ratio of 95 to 105 mol% with respect to the reaction components, adding another dianhydride component, and then adding the remaining diamine component, A method of polymerizing the diamine component and the dianhydride component in substantially equimolar amounts;

(5) reacting some diamine components and some dianhydride components in a solvent so that either one is in excess to form a first composition, and reacting some diamine components with some dianhydride components in another solvent so that either one is in excess. After forming the second composition, the first and second compositions are mixed and polymerization is completed. In this case, if the diamine component is excessive when forming the first composition, the dianhydride component is added in excess in the second composition. When the dianhydride component is excessive in the first composition, the diamine component is excessive in the second composition, and the first and second compositions are mixed so that the total diamine component and dianhydride component used in these reactions are substantially A method of polymerizing them in an equimolar manner may be included.

In the present invention, the polymerization method of the polyamic acid as described above can be defined as a random polymerization method, and the polyimide film manufactured from the polyamic acid of the present invention manufactured through the above process has dimensional stability and chemical resistance. Height can be preferably applied in terms of maximizing the effect of the present invention.

However, since the above polymerization method produces a relatively short length of the repeating unit in the polymer chain described above, there may be limitations in demonstrating each of the excellent properties of the polyimide chain derived from the dianhydride component. Therefore, the polymerization method of polyamic acid that can be particularly preferably used in the present invention may be a block polymerization method.

On the other hand, the solvent for synthesizing polyamic acid is not particularly limited, and any solvent can be used as long as it dissolves polyamic acid, but it is preferable that it is an amide-based solvent.

Specifically, the organic solvent may be an organic polar solvent, and in particular, may be an aprotic polar solvent, for example, N,N-dimethylformamide (DMF), N,N - It may be one or more selected from the group consisting of dimethylacetamide, N-methyl-pyrrolidone (NMP), gamma butyrolactone (GBL), and Diglyme, but is not limited thereto, and may be used alone as needed. Or, two or more types can be used in combination.

In one example, N,N-dimethylformamide and N,N-dimethylacetamide may be particularly preferably used as the organic solvent.

Additionally, in the polyamic acid manufacturing process, fillers may be added to improve various properties of the film such as sliding properties, thermal conductivity, corona resistance, and loop hardness. The added filler is not particularly limited, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.

The particle size of the filler is not particularly limited and may be determined depending on the film properties to be modified and the type of filler to be added. Generally, the average particle diameter is 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 size is below this range, it becomes difficult to achieve a reforming effect, and if the particle size is above this range, the surface properties may be greatly damaged or the mechanical properties may be greatly reduced.

Additionally, the amount of filler added is not particularly limited and may be determined based on the film properties to be modified, the particle size of the filler, etc. Generally, the amount of 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 polyimide.

If the amount of filler added is less than this range, it is difficult to achieve a reforming effect due to the filler, and if it is more than this range, the mechanical properties of the film may be significantly damaged. The method of adding the filler is not particularly limited, and any known method may be used.

In the production method of the present invention, the polyimide film can be produced by thermal imidization and chemical imidization.

In addition, it may be manufactured by a complex imidization method in which thermal imidization and chemical imidization are combined.

The thermal imidization method is a method of inducing an imidization reaction using a heat source such as hot air or an infrared dryer, excluding chemical catalysts.

The thermal imidization method can imidize the amic acid group present in the gel film by heat treating the gel film at a variable temperature in the range of 100 to 600 ℃, specifically 200 to 500 ℃, more specifically, The amic acid group present in the gel film can be imidized by heat treatment at 300 to 500°C.

However, even in the process of forming a gel film, some of the amic acid (about 0.1 mol% to 10 mol%) may be imidized, and for this purpose, the polyamic acid composition is dried at a variable temperature in the range of 50 ℃ to 200 ℃. It can also be included in the scope of the thermal imidization method.

In the case of chemical imidization, a polyimide film can be produced using a dehydrating agent and an imidizing agent according to methods known in the art.

As an example of a complex imidization method, a dehydrating agent and an imidizing agent are added to a polyamic acid solution, then heated at 80 to 200°C, preferably 100 to 180°C, partially cured and dried, and then heated to 5 to 400°C at 200 to 400°C. A polyimide film can be produced by heating for a few seconds.

Meanwhile, the multilayer polyimide film of the present invention described so far can be manufactured using one or more of coextrusion or coating methods.

The co-extrusion method is a method of filling a storage tank with a polyamic acid solution or a polyimide resin prepared by imidizing it, extruding multiple layers on a casting belt using a co-extrusion die, and then curing to produce a polyimide film with a multi-layer structure. As a result, productivity is high and different types of polyimide resins are mixed between the interfaces to ensure high interfacial adhesion reliability.

For example, the method for manufacturing a multilayer polyimide film of the present invention includes a first charging process in which a first solution, which is a first polyamic acid solution or a first polyimide resin prepared by imidizing a first polyamic acid solution, is charged into a first storage tank. Step, a second charging step of filling the second reservoir with a second polyamic acid solution or a second solution of a second polyimide resin prepared by imidizing the second polyamic acid solution, a first flow path connected to the first reservoir, 2 A co-extrusion step of co-extruding the first solution and the second solution through a co-extrusion die in which a second flow path and a third flow path respectively connected to the reservoir are formed inside, and curing the co-extruded first solution and the second solution. It proceeds including a curing step.

The first polyamic acid solution is for forming a core layer, and contains a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA), and paraphenylene diamine (PPD). ) and m-tolidine (m-tolidine) is preferably produced by polymerizing the diamine component.

The second polyamic acid solution is for forming a skin layer, and is a dianhydride containing biphenyltetracarboxylic dianhydride and p-phenylenebis(trimellitate anhydride) (TAHQ). It is preferably produced by polymerizing a water acid component and a diamine component containing m-tolidine.

On the other hand, when using the first polyamic acid solution as the first solution and the second polyamic acid solution as the second solution, the first solution and the second solution co-extruded before the curing step are imidized. It is preferable that the process further includes an imidization step.

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

There is no particular limitation on the metal foil to be used, but when using the flexible metal foil laminate of the present invention for electronic or electrical equipment, for example, copper or copper alloy, stainless steel or its alloy, nickel or nickel alloy (42 alloy) Also included), may be a metal foil containing aluminum or aluminum alloy.

In general flexible metal foil laminates, copper foils such as rolled copper foil and electrolytic copper foil are widely used, and can also be preferably used in the present invention. Additionally, a rust-prevention layer, a heat-resistant layer, or an adhesive layer may be applied to the surface of these metal foils.

In the present invention, the thickness of the metal foil is not particularly limited, and may be sufficient to provide sufficient function depending on the intended use.

The flexible metal foil laminate according to the present invention may have a structure in which metal foil is laminated on at least one side of the multilayer polyimide film.

Hereinafter, the operation and effect of the invention will be described in more detail through specific manufacturing examples and examples of the invention. However, these manufacturing examples and examples are merely presented as examples of the invention, and the scope of the invention is not limited thereby.

Manufacturing example: Preparation of multilayer polyimide film

Core layer manufactured by block copolymerization of biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), paraphenylene diamine (PPD), and m-tolidine (MTD). A first polyamic acid solution to be used was prepared.

Biphenyltetracarboxylic dianhydride, p-phenylenebis(trimellitate anhydride) (TAHQ), and m-tolidine were polymerized to prepare a second polyamic acid solution to be used in manufacturing the skin layer.

The components and composition ratios of the core layer and skin layer are shown in Table 1 below.

Core layer skin layer Dianhydride (mol%) Diamine (mol%) Dianhydride (mol%) Diamine (mol%) PMDA BPDA MTD PPD BPDA TAHQ MTD 40 60 30 70 50 50 100

By co-extruding the previously prepared first polyamic acid solution and the second polyamic acid solution through a co-extrusion method, imidizing, and then curing, each outer surface of the core layer and the opposite surface of the outer surface are centered around the core layer. A three-layer polyimide film with a skin layer was manufactured.

However, here, the core layer was manufactured by co-extruding the first polyamic acid solution, and the skin layer was manufactured by co-extruding the second polyamic acid solution.

When producing the polyamic acid, the solvent is generally an amide-based solvent, such as an aprotic polar solvent (Aprotic solvent), such as N,N'-dimethylformamide, N,N'-dimethylacetamide, and N-methyl-pyrroli. You can use money, or a combination of these.

The dianhydride and diamine components can be added in the form of powder, lump, and solution. It is preferable to add them in the form of powder at the beginning of the reaction to proceed with the reaction, and then add them in the form of a solution to control the polymerization viscosity. .

The obtained polyamic acid solution can be mixed with an imidization catalyst and a dehydrating agent and applied to a support.

Examples of catalysts used include tertiary amines (eg, isoquinoline, β-picoline, pyridine, etc.), and examples of dehydrating agents include, but are not limited to, anhydrous acid.

Examples and Comparative Examples

While manufacturing the three-layer polyimide film according to the above production example, the thicknesses of the core layer and the skin layer were adjusted as shown in Table 2 below to prepare the multilayer polyimide films of Examples 1 to 4 and Comparative Examples 1 to 8. .

However, Comparative Examples 1 and 2 correspond to single-layer polyimide films.

Thickness (㎛) core layer Skin layer* Example 1 48 2 Example 2 46 4 Example 3 44 6 Example 4 42 8 Comparative Example 1 50 0 Comparative Example 2 0 50 Comparative Example 3 40 10 Comparative Example 4 38 12 Comparative Example 5 36 14 Comparative Example 6 34 16 Comparative Example 7 32 18 Comparative Example 8 30 20

*The thickness of the skin layer in Table 2 corresponds to the thickness of the entire skin layer formed on one outer surface of the core layer and the opposite surface of the outer surface. In other words, it corresponds to the entire thickness of the two skin layers. The two skin layers were formed with the same thickness. Therefore, for example, the thickness of the first skin layer of the multilayer (three-layer) polyimide film of Example 2 is 2 μm.

The dielectric constant (Dk), dielectric loss factor (Df), adhesive force, and storage modulus of the produced polyimide film were measured and shown in Table 3 below.

The measurement method for each characteristic is as follows.

(1) Dielectric constant (Dk) measurement

The dielectric constant (Dk) was measured at 10 GHz using an SPDR meter from Keysight.

(2) Dielectric loss factor (Df) measurement

Dielectric loss factor (Df) was measured on films left in an environment at 23°C/50%RH for 24 hours using the cavity resonance method (SPDR) using Keysight's ENA (Vector Network Analyzer).

(3) Adhesion measurement

Adhesion is determined by placing a bonding sheet (1 mil, epoxy type) on both sides of the polyimide film, placing 1/2 oz copper foil on both sides, placing a protective polyimide film, and raising the temperature to 160℃ for 30 minutes. It was heat-compressed at a pressure of 5 MPa. Afterwards, the film was cut into 10 mm widths and a 180° peel test was performed.

(4) Storage modulus measurement

The storage elastic modulus of each film was determined using DMA and the value was measured at 300°C.

characteristic Dk Df Adhesion (gf/cm) 300℃ storage modulus
(MPa) Example 1 3.59 0.00246 1000 1344 Example 2 3.58 0.00243 1000 1288 Example 3 3.58 0.00239 1000 1232 Example 4 3.57 0.00236 1000 1176 Comparative Example 1 3.6 0.00250 600 1400 Comparative Example 2 3.4 0.00160 1000 0 Comparative Example 3 3.56 0.00232 1000 0 Comparative Example 4 3.55 0.00228 1000 0 Comparative Example 5 3.54 0.00225 1000 0 Comparative Example 6 3.54 0.00221 1000 0 Comparative Example 7 3.53 0.00218 1000 0 Comparative Example 8 3.52 0.00214 1000 0

As a result of the measurement, the multilayer (three-layer) polyimide films of Examples 1 to 4 showed the characteristics of a dielectric loss factor of 0.003 or less, an adhesive force of 1,000 gf/cm or more, and a storage modulus at 300°C of 1,000 MPa or more.

In comparison, Comparative Example 1, which corresponds to the core layer of the multilayer polyimide film of Examples 1 to 4 and has a thickness of 50 μm and is a single layer, had very low adhesion.

On the other hand, Comparative Example 2, which corresponds to the skin layer of the multilayer polyimide film of Examples 1 to 4 and has a thickness of 50 μm and is a single layer, had a lower storage modulus at 300°C.

In addition, compared to the multilayer polyimide films of Examples 1 to 4, Comparative Examples 3 to 8 in which the core layer and/or skin layer were thick or thin also had a lower storage modulus at 300°C.

Accordingly, the multilayer polyimide films of Examples 1 to 4 manufactured within the appropriate range of the present application were excellent in all low dielectric, adhesive strength, and high-temperature storage modulus properties. However, if the multilayer polyimide film of the present application was outside the appropriate range of the present application, the multilayer polyimide film of the present application It was confirmed that it was difficult to satisfy both adhesive properties and high temperature storage modulus.

In other words, it was confirmed that a multilayer polyimide film that has excellent low dielectric strength, adhesive strength, and high-temperature storage modulus characteristics, while satisfying all the various conditions applicable to application fields, is a multilayer polyimide film manufactured within the appropriate scope of the present application.

The examples of the multilayer polyimide film and the manufacturing method of the multilayer polyimide film of the present invention are only preferred examples that allow those skilled in the art to easily practice the present invention, and the above-described implementation Since it is not limited to examples, the scope of rights of the present invention is not limited by this. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims. In addition, it will be clear to those skilled in the art that various substitutions, modifications and changes can be made without departing from the technical spirit of the present invention, and it is obvious that parts that can be easily changed by those skilled in the art are also included in the scope of rights of the present invention. .

Claims (12)

It includes at least one skin layer formed on at least one outer surface of the core layer,
Dielectric loss factor is less than 0.003, adhesion is more than 1,000 gf/cm,
The storage modulus at 300°C is more than 1,000 MPa,
The core layer includes a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA);
diamine components including paraphenylene diamine (PPD) and m-tolidine; and
menstruum; Obtained by imidizing only a polyamic acid solution consisting of
Multilayer polyimide film.
According to paragraph 1,
Consisting of a three-layer structure including the skin layer formed on one outer surface of the core layer and the opposite surface of the outer surface,
Multilayer polyimide film.
According to paragraph 2,
The total thickness of the multilayer polyimide film is 10 μm or more and 100 μm or less,
The thickness of the core layer is 70% or more and 95% or less of the total thickness of the multilayer polyimide film,
The sum of the thicknesses of the skin layers formed on one outer surface of the core layer and the opposite surface of the outer surface is 5% or more and 30% or less of the total thickness of the multilayer polyimide film,
Multilayer polyimide film.
delete According to paragraph 1,
The skin layer includes a dianhydride component including biphenyltetracarboxylic dianhydride and p-phenylenebis(trimellitate anhydride) (TAHQ),
Obtained by imidizing a polyamic acid solution containing a diamine component containing m-tolidine,
Multilayer polyimide film.
According to paragraph 1,
Based on the total content of the dianhydride component of 100 mol%, the content of the biphenyltetracarboxylic dianhydride is 50 mol% to 70 mol%, and the content of the pyromellitic dianhydride is 30 mol%. More than 50 mol% or less,
Based on the total content of the diamine component of 100 mol%, the paraphenylene diamine content is 60 mol% or more and 80 mol% or less, and the m-tolidine content is 20 mol% or more and 40 mol% or less,
Multilayer polyimide film.
According to paragraph 1,
The core layer includes a block copolymer containing two or more blocks,
Multilayer polyimide film.
In clause 7,
The block copolymer includes a first block containing 40 mol% or more and 50 mol% or less of the pyromellitic dianhydride based on 100 mol% of the total content of the dianhydride component of the polyimide film,
Comprising a second block containing 30 mol% or more and 40 mol% or less of m-tolidine based on a total content of 100 mol% of the diamine component of the polyimide film,
Multilayer polyimide film.
According to clause 5,
Based on 100 mol% of the total content of the dianhydride component, the content of the biphenyltetracarboxylic dianhydride is 40 mol% to 60 mol% and the content of p-phenylenebis (trimellitate anhydride) It is 40 mol% or more and 60 mol% or less,
Based on the total content of the diamine component of 100 mol%, the content of m-tolidine is 100 mol%,
Multilayer polyimide film.
According to any one of claims 1 to 3 and 5 to 9,
The multilayer polyimide film is manufactured by one or more methods selected from the group consisting of coextrusion and coating.
Multilayer polyimide film.
Comprising a multilayer polyimide film according to any one of claims 1 to 3 and 5 to 9 and an electrically conductive metal foil,
Flexible metal foil laminate.
Comprising a flexible metal foil laminate according to claim 11,
Electronic parts.