Patent Application
20250011542
The present disclosure relates to a multilayer polyimide film having excellent dimensional stability and excellent chemical resistance and, more specifically, to a multilayer polyimide film having not only high thermal dimensional stability and high dimensional stability against moisture but also excellent chemical resistance and to a formation method thereof.
Polyimide (PI) is a polymeric material having the highest level of heat resistance, chemical compatibility, electrical insulation, chemical resistance, and weather resistance of all organic materials on the basis of an imide ring having excellent chemical stability along with a rigid aromatic main chain.
Polyimide films are attracting attention as a material for various electronic devices in need of the properties mentioned above.
Examples of microelectronic components to which a polyimide film is applied include flexible thin circuit boards with high circuit integration density to cope with weight reduction and size reduction in electronic products. In particular, a polyimide film is widely used as an insulating film for thin circuit boards.
The thin circuit board typically has a structure in which a circuit including a metal foil is formed on an insulating film. Such a thin circuit board is referred to as a flexible metal-clad laminate in a broad sense and, in a narrower sense, is sometimes referred to as a flexible copper-clad laminate (FCCL) when using a thin copper plate as a metal foil.
Methods of forming a flexible metal-clad laminate may, for example, include (i) a casting method in which a polyamic acid, a precursor of polyimide, is cast or applied onto a metal foil and then imidized, (ii) a metalizing method in which a metal layer is directly installed on a polyimide film through sputtering, and (iii) a laminate method in which a polyimide film and a metal foil are bonded using heat and pressure through a thermoplastic polyimide.
In particular, the metalizing method is a method of producing a flexible metal-clad laminate by, for example, sputtering a metal such as copper on a polyimide film having a thickness in a range of 20 to 38 μm to sequentially deposit a tie layer and a seed layer. This method is advantageous in forming ultrafine circuits in which a circuit pattern has a pitch of 35 μm or smaller and is widely used to manufacture flexible metal-clad laminates for chip on film (COF).
The polyimide film used for flexible metal-clad laminates manufactured by the metalizing method must have high dimensional stability. Although dimensional stability is typically measured by thermal dimensional stability, expressed by the coefficient of thermal expansion, dimensional stability against moisture, expressed by the coefficient of hygroscopic expansion, is gradually becoming more important as much as thermal dimensional stability.
In other words, there is a growing demand for polyimide films having both excellent thermal dimensional stability and dimensional stability against moisture. However, when actually designing a polyimide film having a structure in which the thermal dimensional stability is high while the coefficient of thermal expansion is low, a problem that the dimensional stability against moisture decreases emerges.
Additionally, polyimide films having high dimensional limitations typically have a problem in that chemical resistance (especially alkali resistance) deteriorates.
Therefore, there is an urgent need for a polyimide film having not only high thermal dimensional stability and high dimensional stability against moisture but also excellent chemical resistance.
The foregoing background description is intended to provide an understanding of the background of the present disclosure and may include matters not known in the related art to those skilled in the field to which the technology belongs.
Accordingly, the present disclosure aims to provide a polyimide film having not only high thermal dimensional stability and high dimensional stability against moisture but also excellent chemical resistance.
However, the problems to be solved by the present disclosure are not limited to the above description, and other problems can be clearly understood by those skilled in the art from the following description.
In one aspect of the present disclosure for achieving the objective as described above, a multilayer polyimide film including a core layer and first and second skin layers formed respectively on first and second outer surfaces of the core layer, the second outer surface being a surface opposite to the first outer surface,
In another aspect of the present disclosure, a flexible metal-clad laminate including the multilayer polyimide film described above and an electrically conductive metal foil
In a further aspect of the present disclosure, an electronic component including the flexible metal-clad laminate described above
The present disclosure provides a polyimide film in which the composition ratio, reaction ratio, and the like of acid dianhydride and diamine components are adjusted, thereby providing a polyimide film having not only excellent thermal dimensional stability and dimensional stability against moisture but also excellent chemical resistance.
Such a polyimide film can be applied to various fields in need of a polyimide film having excellent dimensional stability and chemical resistance, for example, flexible metal-clad laminates manufactured by a metalizing method or electronic components including such flexible metal-clad laminates.
All terms including technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Therefore, the embodiments described herein are merely examples and do not exhaustively present the technical spirit of the present disclosure. Accordingly, it should be appreciated that there may be various equivalents and modifications that can replace the embodiments at the time at which the present application is filed.
As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise”, “include”, “have”, and the like when used herein, specify the presence of stated features, integers, steps, components, or combinations thereof but do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.
As used herein, although the term “acid dianhydride” is intended to include precursors or derivatives thereof, these compounds may not technically be acid dianhydride. Nevertheless, these compounds will react with diamine to form polyamic acids, which will be converted to polyimides once more.
As used herein, although the term “diamine” is intended to include precursors or derivatives thereof, these compounds may not technically be diamines. Nevertheless, these compounds will react with dianhydride to form polyamic acids, which will be converted to polyimides once more.
When an amount, concentration, other value, or parameter is given herein as a range, preferred range, or enumeration of preferred upper values and preferred lower values, it is to be understood to specifically disclose all ranges formed by a pair of any upper range limit or a preferred value and any lower range limit or a preferred value, regardless of whether the ranges are additionally disclosed.
When a range of numerical values is mentioned herein, this range is intended to include not only the endpoints but also all integers and fractions within the range, unless otherwise stated. The scope of the present disclosure is not intended to be limited to the specific values mentioned when defining the scope.
A multilayer polyimide film, according to one embodiment of the present disclosure, includes a core layer and first and second skin layers formed respectively on first and second outer surfaces of the core layer, the second outer surface being a surface opposite to the first outer surface, wherein a coefficient of thermal expansion is 2.0 ppm/° C. or higher and 6.0 ppm/° C. or lower, and a coefficient of hygroscopic expansion is 3.0 ppm/RH % or higher and 6.0 ppm/RH % or lower.
In other words, the multilayer polyimide film may be a multilayer polyimide film having a three-layer structure including the core layer, and the first and second skin layers around the core layer, wherein the first and second skin layers are formed on the first and second outer surfaces of the core layer, respectively, the second outer surface being a surface opposite to the first outer surface.
For example, the coefficient of thermal expansion may be 2.0 ppm/° C. or higher and 5.5 ppm/° C. or lower.
For example, the coefficient of hygroscopic expansion may be 4.0 ppm/RH % or higher and 6.0 ppm/RH % or lower.
In one embodiment, after immersing the multilayer polyimide film in 15 wt % of a NaOH aqueous solution at a temperature of 60° C. for 1 hour, a mass loss in the multilayer polyimide film measured may be 2 mass % or less.
For example, a weight loss in the multilayer polyimide film may be 1.5 mass % or less, 1.4 mass % or less, or 1.3 mass % or less.
In one embodiment, the core layer of the multilayer polyimide film may be obtainable by reacting a polyamic acid solution through an imidization reaction, the polyamic acid solution containing an acid dianhydride component including two or more selected from the group consisting of biphenyl-tetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), oxydiphthalic anhydride (ODPA), and benzophenone tetracarboxylic dianhydride (BTDA), and a diamine component including two or more selected from the group consisting of para-phenylenediamine (PPD), m-tolidine, and 1,3-bis(aminophenoxy)benzene (TPE-R).
For example, the core layer may be obtainable by reacting the polyamic acid solution through the imidization reaction, the polyamic acid solution containing the acid dianhydride component including biphenyl-tetracarboxylic dianhydride and pyromellitic dianhydride, and the diamine component including para-phenylenediamine and m-tolidine.
In one embodiment, one or more of the first and second skin layers may be obtainable by reacting a polyamic acid solution through an imidization reaction, the polyamic acid solution containing an acid dianhydride component including one or more selected from the group consisting of biphenyl-tetracarboxylic dianhydride, pyromellitic dianhydride, oxydiphthalic anhydride, and benzophenone tetracarboxylic dianhydride, and a diamine component including one or more selected from the group consisting of para-phenylenediamine, m-tolidine, oxydianiline (ODA), and 1,3-bis(aminophenoxy)benzene.
In other words, the first and second skin layers may be the same or different in component and composition ratio.
On the other hand, one or more of the first and second skin layers may be obtainable by reacting the polyamic acid solution through the imidization reaction, the polyamic acid solution containing the acid dianhydride component including one or more selected from the group consisting of biphenyl-tetracarboxylic dianhydride and pyromellitic dianhydride, and the diamine component including one or more selected from the group consisting of para-phenylenediamine, m-tolidine, and oxydianiline.
For example, in one or more of the first and second skin layers, oxydianiline alone, a combination of oxydianiline and para-phenylenediamine, or a combination of para-phenylenediamine, m-tolidine, and oxydianiline may be used as the diamine component.
In one embodiment, in the core layer, the biphenyl-tetracarboxylic dianhydride may have a content of 40 mol % or more and 60 mol % or less, and the pyromellitic dianhydride may have a content of 40 mol % or more and 60 mol % or less, based on 100 mol % of the total content of the acid dianhydride component. Additionally, the para-phenylenediamine may have a content of 50 mol % or more and 70 mol % or less, and the m-tolidine may have a content of 30 mol % or more and 50 mol % or less, based on 100 mol % of the total content of the diamine component.
In one embodiment, in one or more of the first and second skin layers, the biphenyl-tetracarboxylic dianhydride may have a content of 30 mol % or more and 100 mol % or less, and the pyromellitic dianhydride may have a content of 70 mol % or less, based on 100 mol % of the total content of the acid dianhydride component. Additionally, the para-phenylenediamine may have a content of 60 mol % or less, the m-tolidine may have a content of 75 mol % or less, and the oxydianiline may have a content of 10 mol % or more and 100 mol % or less, based on 100 mol % of the total content of the diamine component.
In the present disclosure, with the increasing content of para-phenylenediamine, a rigid monomer, the polyimide synthesized has a further linear structure and contributes to the improvement of the mechanical properties of the polyimide.
Additionally, m-tolidine has a particularly hydrophobic methyl group and thus contributes to the low hygroscopicity related to the dimensional stability of the polyimide film against moisture.
The polyimide chain of the present disclosure, derived from biphenyl-tetracarboxylic dianhydride, has a structure called a charge transfer complex (CTC), that is, a regular linear structure in which an electron donor and an electron acceptor are positioned close to each other, and the intermolecular interaction is strengthened.
Such a structure is effective in preventing hydrogen bonding with moisture and thus has an impact on reducing the moisture absorption rate, thereby maximizing the effect of reducing the hygroscopicity, which affects the dimensional stability against moisture, of the polyimide film.
Additionally, pyromellitic dianhydride, the acid dianhydride component having a relatively rigid structure, is preferable in terms of providing appropriate elasticity to the polyimide film.
The content ratio of the acid dianhydride is important for the polyimide film to have excellent dimensional stability. For example, as the content ratio of biphenyl-tetracarboxylic dianhydride decreases, a low moisture absorption rate based on the CTC structure is hard to expect, and the dimensional stability against moisture is reduced.
Additionally, while biphenyl-tetracarboxylic dianhydride contains two benzene rings corresponding to the aromatic moiety, pyromellitic dianhydride contains one benzene ring corresponding to the aromatic moiety.
The increase in the content of pyromellitic dianhydride in the acid dianhydride component may be understood as an increase in the imide group within the molecule based on the same molecular weight, indicating that the ratio of the imide group derived from the pyromellitic dianhydride in the polyimide polymer chain increases relatively compared to that of the imide group derived from biphenyl-tetracarboxylic dianhydride.
In other words, an increase in the content of pyromellitic dianhydride may be seen as a relative increase in the imide group in the entire polyimide film, making it difficult to expect high dimensional stability against moisture due to a low moisture absorption rate.
On the contrary, when the content ratio of pyromellitic dianhydride decreases, this means that the component having a relatively rigid structure is reduced, so the elasticity of the polyimide film may deteriorate below the desired level.
For this reason, when the content of the biphenyl-tetracarboxylic dianhydride exceeds the above range, or the content of the pyromellitic dianhydride is lower than the above range, the dimensional stability of the polyimide film may be reduced.
On the contrary, when the content of the biphenyl-tetracarboxylic dianhydride is lower than the above range, or the content of the pyromellitic dianhydride exceeds the above range, the dimensional stability of the polyimide film may be adversely affected.
The preparation of a polyamic acid in the present disclosure may, for example, involve:
In the present disclosure, such a polymerization method of the polyamic acid described above may be defined as a random polymerization method. Additionally, the polyimide film of the present disclosure, formed from the polyamic acid prepared through such a process described above, is preferably applicable in terms of maximizing the effect of the present disclosure for improving dimensional stability and chemical resistance.
However, the polymerization method makes the length of the repeating unit in the polymer chain described above relatively short, so there may be limitations in demonstrating each of the excellent properties of the polyimide chain derived from the acid dianhydride component. Therefore, block polymerization may be performed as the polymerization method of the polyamic acid, which is further preferably usable in the present disclosure.
On the other hand, the solvent for synthesizing the polyamic acid is not particularly limited, and any solvent capable of dissolving the polyamic acid may be usable. However, an amide-based solvent is preferably used.
Specifically, the organic solvent may be a polar organic solvent, which may be, in particular, a polar aprotic solvent. Examples thereof may include one or more selected from the group consisting of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl-pyrrolidone (NMP), gamma-butyrolactone (GBL), and diglyme, but the organic solvent is not limited thereto. If necessary, the organic solvent may be used alone, or two or more types may be used in combination.
In one example, N,N-dimethylformamide and N,N-dimethylacetamide are further preferably used as the organic solvent.
Additionally, in the polyamic acid preparation process, fillers may be added to improve various properties of the film, such as sliding properties, thermal conductivity, corona resistance, loop hardness, and the like. The filler added is not particularly limited, but preferred examples thereof include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like.
The particle diameter of the filler is not particularly limited but may be determined depending on the properties of a film to be modified and the type of fillers to be added. Typically, the average particle diameter is in a range of 0.05 to 100 μm, which is preferably in the range of 0.1 to 75 μm, more preferably in the range of 0.1 to 50 μm, and even more preferably in the range of 0.1 to 25 μm.
When the particle diameter is smaller than the above range, the modification effect may be challenging to exhibit. On the contrary, when the particle diameter exceeds the above range, the surface properties may be greatly damaged, or the mechanical properties may significantly deteriorate.
Additionally, the amount of the filler added is not particularly limited but may be determined by the properties of a film to be modified, the particle diameter of the filler, or the like. Typically, the amount of the filler added is in a range of 0.01 to 100 parts by weight, which is preferably in the range of 0.01 to 90 parts by weight and more preferably in the range of 0.02 to 80 parts by weight, based on 100 parts by weight of the polyimide.
When the amount of the filler added is smaller than the above range, the modification effect may be challenging to exhibit due to the filler. On the contrary, when the amount of the filler added exceeds the above range, the mechanical properties of the film may be significantly damaged. The method of adding the filler is not particularly limited, and any known methods may be used.
In the formation method of the present disclosure, the polyimide film may be formed by a thermal imidization method and a chemical imidization method.
Additionally, the polyimide film may be formed by a complex imidization method in combination of the thermal imidization and the chemical imidization methods.
The thermal imidization method is a method of inducing an imidization reaction using a heat source such as an infrared dryer or hot air, without involving a chemical catalyst.
*The thermal imidization method may enable the amic acid group present in a gel film to be imidized by subjecting the gel film to heat treatment at a variable temperature in a range of 100° C. to 600° C. Specifically, the heat treatment may be performed at a temperature in a range of 200° C. to 500° C., which is more specifically in the range of 300° C. to 500° C., to imidize the amic acid group present in the gel film.
However, even in the gel film formation process, some of the amic acid (about 0.1 mol % to 10 mol %) may be imidized. To this end, the polyamic acid composition may be dried at a variable temperature in a range of 50° C. to 200° C., which may also fall within the scope of the thermal imidization method.
In the case of the chemical imidization method, a dehydrating agent and an imidizing agent may be used according to methods known in the art to form the polyimide film.
As one example of the complex imidization method, a dehydrating agent and an imidizing agent may be introduced into a polyamic acid solution, heated at a temperature in a range of 80° C. to 200° C., which is preferably in the range of 100° C. to 180° C., partially cured and dried, and then heated at a temperature in a range of 200° C. to 400° C. for 5 to 400 seconds, thereby forming the polyimide film.
On the other hand, the multilayer polyimide film of the present disclosure, described hereinabove, may be formed using one or more methods among co-extrusion or coating.
The co-extrusion method is a method of forming a polyimide film having a multilayer structure by filling a storage tank with a polyamic acid solution or a polyimide resin prepared by imidizing the polyamic acid solution, extruding multiple layers on a casting belt using a co-extrusion die, and then curing the resulting product, which has high productivity and enables high interfacial adhesion reliability to be obtained by mixing types of polyimide resins that differ in interface.
For example, the method of forming the multilayer polyimide film of the present disclosure is performed by including the following steps: firstly filling a first storage tank with a first solution which is a first polyamic acid solution or first polyimide resin prepared by imidizing the first polyamic acid solution; secondly filling a second storage tank with a second solution which is a second polyamic acid solution or second polyimide resin prepared by imidizing the second polyamic acid solution; extruding the first and second solutions through co-extrusion using a co-extrusion die in which a first flow path connected to the first storage tank, and second and third flow paths each independently connected to the second storage tank are formed; and curing the resulting first and second solutions obtained through the co-extrusion.
The first polyamic acid solution, used to form the core layer, is preferably prepared by polymerizing an acid dianhydride component including two or more selected from the group consisting of biphenyl-tetracarboxylic dianhydride, pyromellitic dianhydride, oxydiphthalic anhydride, and benzophenone tetracarboxylic dianhydride, and a diamine component including two or more selected from the group consisting of para-phenylenediamine, m-tolidine, oxydianiline, and 1,3-bis(aminophenoxy)benzene.
The second polyamic acid solution, used to form the first and second skin layers, is preferably prepared by polymerizing an acid dianhydride component including one or more selected from the group consisting of biphenyl-tetracarboxylic dianhydride, pyromellitic dianhydride, oxydiphthalic anhydride, and benzophenone tetracarboxylic dianhydride, and a diamine component including one or more selected from the group consisting of para-phenylenediamine, m-tolidine, oxydianiline, and 1,3-bis(aminophenoxy)benzene.
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, a step of imidizing the resulting first and second solutions obtained through the co-extrusion is preferably further included and performed before the curing step.
The present disclosure provides a flexible metal-clad laminate including the multilayer polyimide film described above and an electrically conductive metal foil.
The metal foil used is not particularly limited. However, when using the flexible metal-clad laminate of the present disclosure for electronic or electrical devices, the metal foil may, for example, include copper or an alloy thereof, stainless steel or an alloy thereof, nickel or an alloy thereof (including Alloy 42), and aluminum or an alloy thereof.
In typical flexible metal-clad laminates, copper foils, such as rolled copper foil and electrolytic copper foil, are widely used and are also preferably used in the present disclosure. Additionally, an anti-rust layer, a heat-resistant layer, or an adhesive layer may be applied onto the surface of such metal foils.
The thickness of the metal foil is not particularly limited in the present disclosure and may be any thickness capable of demonstrating sufficient functions depending on the intended use.
The flexible metal-clad laminate, according to the present disclosure, may have a structure in which the metal foil is laminated on at least one surface of the multilayer polyimide film.
Hereinafter, the action and effect of the present disclosure will be described in detail through specific examples and preparation examples of the disclosure. However, such examples and preparation examples are provided only for illustrative purposes, and the scope of the present disclosure is not limited to the following embodiments.
Acid dianhydride and diamine components were selected from among biphenyl-tetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), para-phenylenediamine (PPD), m-tolidine (MTD), and oxydianiline (ODA) and then allowed to react through polymerization reactions to prepare a first polyamic acid solution to be used in the formation of a core layer.
Acid dianhydride and diamine components were selected from among biphenyl-tetracarboxylic dianhydride, pyromellitic dianhydride, para-phenylenediamine, m-tolidine, and oxydianiline and then allowed to react through polymerization reactions to prepare a second polyamic acid solution to be used in the formation of first and second skin layers.
The first and second polyamic acid solutions prepared above were extruded through a co-extrusion method, imidized, and then cured to form a multilayer polyimide film in which the first and second skin layers were formed around the core layer.
However, in this case, the core layer was formed by the co-extrusion of the first polyamic acid solution, and the first and second skin layers were formed by the co-extrusion of the second polyamic acid solution.
When preparing the polyamic acid, a solvent used, typically an amide-based solvent, is a polar aprotic solvent, which may be N,N′-dimethylformamide, N,N′-dimethylacetamide, N-methyl-pyrrolidone, or a combination thereof.
The acid dianhydride and diamine components are enabled to be introduced in a solution, powder, or lump form. Preferably, the reaction occurs by introducing the acid dianhydride and diamine components in a powder form at the beginning of the reaction and then in a solution form to control the polymerization viscosity.
The polyamic acid solution obtained in such a manner may be mixed with an imidization catalyst and a dehydrating agent so as to be applied onto a support.
Examples of the catalyst used include tertiary amines (for example, isoquinoline, β-picoline, pyridine, and the like), and examples of the dehydrating agent include anhydrous acids, but the catalyst and the dehydrating agent are not limited thereto.
In Examples 1 to 5 and Comparative Examples 1 to 6, each multilayer polyimide film was formed according to the preparation example by adjusting the contents of the acid dianhydride and diamine components, as shown in Table 1 below.
However, Comparative Examples 1 to 4 correspond to single-layer polyimide films.
The coefficient of thermal expansion (CTE), coefficient of hygroscopic expansion (CHE), and chemical resistance of such formed polyimide films were measured. The results thereof are shown in Table 2 below.
The coefficient of thermal expansion (CTE) was measured using a thermomechanical analyzer, a Q400 model purchased from TA. Each multilayer polyimide film formed was cut into a size of a width of 4 mm and a length of 20 mm. While applying a tension of 0.05 N under a nitrogen atmosphere, the resulting film was heated from 30° C. to 400° C. at a speed of 10° C./min and then cooled again at a speed of 10° C./min to measure the slope from 50° C. to 200° C.
The coefficient of hygroscopic expansion (CHE) was determined by, while applying the minimum weight (about 1 g for a sample with a size of 25 mm×150 mm) to prevent such a formed multilayer polyimide film from loosening, adjusting the humidity to 3% RH at a temperature of 25° C. so that moisture is absorbed until being completely saturated to measure the dimension, adjusting the humidity to 90% RH thereafter so that moisture is absorbed in the same manner until being completely saturated to measure the dimension, and then measuring the dimensional change rate from both of the results.
Such a formed multilayer polyimide film was immersed in 15 wt % of a NaOH aqueous solution at a temperature of 60° C. for 1 hour. Then, the amount of mass loss in the multilayer polyimide film was measured and expressed as a percentage.
As a result of the measurement, the multilayer polyimide films of Examples 1 to 5 were characterized by having a coefficient of thermal expansion of 2.0 ppm/° C. or higher and 6.0 ppm/° C. or lower, a coefficient of hygroscopic expansion of 3.0 ppm/RH % or higher and 6.0 ppm/RH % or lower, and a mass loss of 2 mass % or less.
In contrast, in the case of Comparative Example 1, the single layer whose components and composition ratio were the same as those of the skin layer of the multilayer polyimide film of Example 1, Comparative Example 2, the single layer whose components and composition ratio were the same as those of the skin layer of the multilayer polyimide film of Example 3, and Comparative Example 3, the single layer whose components and composition ratio were the same as those of the skin layer of the multilayer polyimide film of Example 4, it was confirmed that the coefficient values of thermal expansion and hygroscopic expansion increased compared to the case of the multilayer polyimide films of Examples 1, 3, and 4, respectively, so the dimensional stability was low.
Additionally, in the case of Comparative Example 4, the single layer whose components and composition ratio were the same as those of the core layer of the multilayer polyimide film of Example 1, it was confirmed that the coefficients of thermal expansion and hygroscopic expansion were lower than those of the multilayer polyimide film of Examples 1, so the dimensional stability was excellent, but the chemical resistance significantly deteriorated.
On the other hand, it was confirmed that the multilayer polyimide film of Comparative Example 5, in which the core layer was modified by adding oxydianiline as the core layer component to the multilayer polyimide film of Example 1 and not using m-tolidine while adjusting the composition ratio thereof, had both poor dimensional stability and chemical resistance compared to the multilayer polyimide film of Example 1.
It was confirmed that the multilayer polyimide film of Comparative Example 5 had both poor dimensional stability and chemical resistance compared to the multilayer polyimide film of Example 2, in which the composition ratio of acid dianhydride in the skin layer was adjusted compared to Example 1.
Additionally, it was confirmed that the multilayer polyimide film of Comparative Example 6, in which the skin layer was modified by adding para-phenylenediamine as the skin layer component to the multilayer polyimide film of Example 1 while adjusting the composition ratio thereof, had significantly poor chemical resistance compared to the multilayer polyimide film of Example 1.
It was confirmed that the multilayer polyimide film of Comparative Example 6 had significantly poor chemical resistance compared to the multilayer polyimide film of Example 2, in which the composition ratio of acid dianhydride in the skin layer was adjusted compared to Example 1.
Therefore, the multilayer polyimide films of Examples 1 to 5 formed within the appropriate range herein were excellent in all of the thermal dimensional stability, dimensional stability against moisture, and chemical resistance. However, when formed without falling within the appropriate range herein, it was confirmed that all of the thermal dimensional stability, dimensional stability against moisture, and chemical resistance of the multilayer polyimide films herein are challenging to fulfill.
Additionally, it was confirmed that the multilayer polyimide films of Examples 1 to 5 formed within the appropriate range herein had appropriate ranges of elastic modulus and glass transition temperature applicable to various fields.
In other words, it was confirmed that the polyimide film formed within the appropriate range herein was a polyimide film having excellent dimensional stability and chemical resistance while satisfying various requirements enabling the use thereof in application fields.
The embodiments of the present disclosure regarding the multilayer polyimide film and the formation method thereof are only preferred embodiments that allow those skilled in the art to easily practice the present disclosure in the technical field to which the present disclosure belongs and are not limited to the examples described above. Accordingly, the scope of the present disclosure is not limited thereby. Thus, the true technical protection scope of the present disclosure should be defined by the technical spirit of the appended claims. Additionally, those skilled in the art will appreciate that various modifications, alternatives, and substitutions are possible, without departing from the scope and spirit of the present disclosure as disclosed in the accompanying claims. Furthermore, it is apparent that modifications capable of being easily embodied by those skilled in the art are included within the scope of the present disclosure.
The present disclosure provides a polyimide film in which the composition ratio, reaction ratio, and the like of acid dianhydride and diamine components are adjusted, thereby providing a polyimide film having not only excellent thermal dimensional stability and dimensional stability against moisture but also excellent chemical resistance.
Such a polyimide film may be applied to various fields in need of a polyimide film having excellent dimensional stability and chemical resistance, for example, flexible metal-clad laminates manufactured by a metalizing method or electronic components including such flexible metal-clad laminates.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0157388 | Nov 2021 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/017984 | 11/15/2022 | WO |
