Polyimide composition, its manufacturing method, polyimide film, and flexible copper-clad laminate

Abstract

To provide a polyimide composition, a method for preparing the polyimide composition, a polyimide film, and a flexible copper-clad laminate.SOLUTION: A polyimide composition according to an example of the present invention includes a dianhydride, and a diamine, and the diamine comprises an aromatic diamine, and an aliphatic diamine.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyimide composition, a method for producing the same, a polyimide film, and a flexible copper-clad laminate. [Background technology]

[0002] Flexible printed circuit boards (FPCBs) are a type of printed circuit board made by laminating thin copper foil and insulating film, making them flexible and capable of repeated deformation. They are thin and suitable for use in moving parts, and demand is increasing as an essential material for the miniaturization, lightness, and thinning of electronic devices in recent years. Flexible copper clad laminates (FCCLs), the basic raw material for FPCBs, are typically made of a laminated structure of copper foil and polyimide, and are a key raw material for the manufacture of flexible circuit boards. They are gaining attention as a key material for precision electronic components due to their excellent heat resistance, flexibility, and chemical resistance, as well as their ease of workability.

[0003] Polyimide (PI) is a polymeric material that possesses excellent mechanical strength, chemical resistance, weather resistance, and heat resistance due to the chemical stability of the imide ring. Furthermore, it has excellent electrical properties, such as insulating properties and a low dielectric constant, and active research is underway to use polyimide as a lightweight and flexible polymeric substrate material. Polyimide is a key raw material for flexible circuit boards and flexible copper-clad laminates used in various electronic devices. As technological development related to flexible circuit boards, a core component of next-generation smart devices, is gaining momentum, so too is related research.

[0004] To manufacture high-performance FCCLs, copper foil, the conductive layer material, and polyimide, the insulating layer material, must be bonded without the use of an adhesive layer, requiring high adhesive strength between them. However, polyimides without polar groups on their surface have low adhesion to metals, resulting in reduced durability due to their adhesive properties and the risk of peeling from the metal. Ultimately, polyimides with low copper foil adhesion require a separate polyimide adhesive layer material and process. Furthermore, existing polyimides have disadvantages in bending evaluation due to their low yield point and elongation.

[0005] The above-mentioned background art was possessed or acquired by the inventors in the process of deriving the contents of the disclosure of this application, and is not necessarily publicly known art that was disclosed to the general public prior to the filing of this application. Summary of the Invention [Problem to be solved by the invention]

[0006] To solve the above problems, the present invention provides a polyimide composition having an improved yield point and elongation, a high elastic recovery rate, and copper foil adhesion, a method for producing the same, a polyimide film, and a flexible copper-clad laminate.

[0007] However, the problems that the present invention aims to solve are not limited to those mentioned below, and other problems not mentioned will be clearly understood by those skilled in the art from the description below. [Means for solving the problem]

[0008] The polyimide composition according to the present invention comprises a dianhydride and a diamine, and the diamine comprises an aromatic diamine and an aliphatic diamine.

[0009] In one embodiment, the dianhydride is 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA). Anhydride), pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4'-(hexafluoropropylidene)diphthalic anhydride (6FDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), benzophenonetetracarboxylic dianhydride (BTDA), biscarboxyphenyldimethylsilane dianhydride (SiDA), bisdicarboxyphenoxydiphenylsulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SODPA), isopropylidenediphenoxybisphthalic anhydride (6HBDA), cyclobutane dianhydride (CBDA), cyclopentane dianhydride (CPDA), cyclohexane dianhydride (CHDA), and bicyclohexane dianhydride (HBPDA).

[0010] In one embodiment, the dianhydride may be 30 mol % to 70 mol % of the polyimide composition.

[0011] In one embodiment, the aromatic diamine is 4,4'-oxydianiline (ODA), 2-(4-aminophenyl)benzoxazol-5-amine (APBOA), p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), 2,4-toluenediamine (TDA), m-xylylenediamine (m-XDA), p-xylylenediamine (p-XDA), 1,5-diaminonaphthalene (DAN), 2,6- The additive may include at least one selected from the group consisting of diaminonaphthalene (DAN), 3,5-diaminobenzoic acid (DABA), 4,4'-methylenedianiline (MDA), 2-(4-aminophenyl)-5-amino-benzimidazole (PBI), 1,3-bis(4-aminophenoxy)benzene (TPER), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and m-toluidine.

[0012] In one embodiment, the aliphatic diamine may include at least one selected from the group consisting of polyetheramine (PEA), siloxane-based diamine, and silicone-based diamine.

[0013] In one embodiment, the diamine may be 30 mol % to 70 mol % of the polyimide composition.

[0014] In one embodiment, the aromatic diamine may be 50 to 90 parts by mole weight, and the aliphatic diamine may be 10 to 50 parts by mole weight, relative to 100 parts by mole weight of the dianhydride.

[0015] In one embodiment, the aliphatic diamine may have a molecular weight of 500 g / mol to 5000 g / mol.

[0016] In one embodiment, the method further comprises an organic solvent; and the organic solvent may comprise at least one selected from the group consisting of dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), cyclohexanone, acetone, diethyl acetate, and m-cresol.

[0017] In one embodiment, the polyimide composition may be a polyamic acid or may be soluble.

[0018] In one embodiment, the solid content may be 15% to 40% by weight.

[0019] A method for producing a polyimide composition according to the present invention includes the steps of: introducing an organic solvent into a reactor at 40°C to 60°C; dissolving an aromatic diamine in the organic solvent to prepare a diamine solution; and introducing a dianhydride and an aliphatic diamine into the diamine solution.

[0020] In one embodiment, the method may further include, after the step of adding the aliphatic diamine, a step of increasing the temperature of the reactor to 160° C. or more to carry out an imidization reaction.

[0021] The polyimide film according to the present invention is obtained by curing the polyimide composition according to the present invention or the polyimide composition produced by the method for producing a polyimide composition according to the present invention.

[0022] In one embodiment, the polyimide film may be obtained by coating the polyimide composition on a copper foil, drying the coating, and then curing the coating. The drying may be performed at a temperature of 140°C to 180°C for 1 minute to 20 minutes, and the curing may be performed at a temperature of 250°C to 400°C.

[0023] In one embodiment, the polyimide film may have an elastic recovery rate of 80% or more in a tensile strength range of 1% to 50%.

[0024] In one embodiment, the polyimide film may have an adhesive strength of 300 gf / cm or more to a lamination copper foil.

[0025] The flexible copper-clad laminate according to the present invention comprises a metal foil; and a polyimide film laminated on one or both sides of the metal foil; wherein the polyimide film is the polyimide film according to the present invention. [Effects of the Invention]

[0026] The present invention can provide a polyimide composition having an improved yield point and elongation.

[0027] Specifically, the polyimide composition according to the present invention can be used to produce polyimide films and flexible copper-clad laminates having high elastic recovery and copper foil adhesion, which can be applied to existing processes. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following examples are described in detail. However, since various modifications can be made to the examples, the scope of the patent application is not limited or restricted by these examples. It should be understood that all modifications, equivalents, or alternatives to the examples are included in the scope of the patent application.

[0029] The terms used in the examples are used merely for the purpose of explanation and should not be construed as limiting. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this specification, the terms "comprise" or "have" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0030] Unless otherwise specified, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the examples belong. Terms commonly used and as defined in dictionaries should be interpreted to have a meaning consistent with the contextual meaning of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0031] Furthermore, when describing the embodiments, if it is determined that a detailed description of related prior art would unnecessarily obscure the gist of the embodiments, the detailed description will be omitted. Furthermore, in describing components of the embodiments, terms such as "first," "second," "A," "B," "(a)," and "b" may be used. These terms are merely used to distinguish the component from other components, and do not limit the essence, procedure, or order of the components. When a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that additional components may also be "coupled," "coupled," or "connected" between the components.

[0032] Components included in one embodiment and components having common functions will be described using the same names in other embodiments. Unless otherwise specified, the description of one embodiment is applicable to other embodiments, and detailed description will be omitted to the extent that it overlaps.

[0033] The polyimide composition according to the present invention comprises a dianhydride and a diamine, and the diamine comprises an aromatic diamine and an aliphatic diamine.

[0034] Conventional polyimides have low yield points and elongations, which are disadvantageous in bending tests. In addition, polyimides without polar groups on their surfaces have low copper foil adhesion, resulting in reduced durability and peeling from the metal, requiring a separate polyimide adhesive layer material and process. The polyimide composition according to the present invention contains a dianhydride, an aromatic diamine, and an aliphatic diamine, thereby providing a polyimide material with elasticity that can be applied to existing processes, thereby providing a flexible copper-clad laminate with excellent performance without using a separate adhesive layer.

[0035] According to one embodiment, the dianhydride is 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA). Anhydride), pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), 4,4'-(hexafluoropropylidene)diphthalic anhydride (6FDA), oxydiphthalic dianhydride (ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), benzophenonetetracarboxylic dianhydride (BTDA), biscarboxyphenyldimethylsilane dianhydride (SiDA), bisdicarboxyphenoxydiphenylsulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SODPA), isopropylidenediphenoxybisphthalic anhydride (6HBDA), cyclobutane dianhydride (CBDA), cyclopentane dianhydride (CPDA), cyclohexane dianhydride (CHDA), and bicyclohexane dianhydride (HBPDA).

[0036] Preferably, the dianhydride compound may be 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA). The dianhydride has excellent solubility in solvents, facilitating the preparation of soluble polyimides, and can maintain the physical properties of polyimides, such as heat resistance and coefficient of thermal expansion (CTE).

[0037] According to one embodiment, the dianhydride may be 30 mol % to 70 mol % of the polyimide composition.

[0038] Preferably, the dianhydride may be present in an amount of 30 mol % to 60 mol %, or may be present in an amount of 40 mol % to 60 mol % of the polyimide composition.

[0039] If the dianhydride is less than 30 mol % of the polyimide composition, the heat resistance and thermal expansion coefficient properties of the polyimide may be reduced.

[0040] According to one embodiment, the aromatic diamine is 4,4'-oxydianiline (ODA), 2-(4-aminophenyl)benzoxazol-5-amine (APBOA), p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), 2,4-toluenediamine (TDA), m-xylylenediamine (m-XDA), p-xylylenediamine (p-XDA), 1,5-diaminonaphthalene (DAN), 2,6- The additive may include at least one selected from the group consisting of diaminonaphthalene (DAN), 3,5-diaminobenzoic acid (DABA), 4,4'-methylenedianiline (MDA), 2-(4-aminophenyl)-5-amino-benzimidazole (PBI), 1,3-bis(4-aminophenoxy)benzene (TPER), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and m-toluidine.

[0041] Preferably, the aromatic diamine may be 4,4'-oxydianiline (ODA), which can provide the polyimide composition with physical properties such as heat resistance and coefficient of thermal expansion (CTE), thereby maintaining the physical properties of the polyimide.

[0042] According to an embodiment, the aliphatic diamine may include at least one selected from the group consisting of polyetheramine (PEA), siloxane-based diamine, and silicone-based diamine.

[0043] Preferably, the aliphatic diamine may be polyetheramine (PEA), which can improve the elongation and elastic recovery of the polyimide composition.

[0044] According to one embodiment, the diamine may be 30 mol % to 70 mol % of the polyimide composition.

[0045] Preferably, the diamine may account for 30 mol % to 60 mol %, or may account for 40 mol % to 60 mol % of the polyimide composition.

[0046] According to one embodiment, the aromatic diamine may be 50 to 90 parts by mole weight, and the aliphatic diamine may be 10 to 50 parts by mole weight, relative to 100 parts by mole weight of the dianhydride.

[0047] If the aromatic diamine and aliphatic diamine are outside the above ranges, the content of aromatic diamine will be reduced, resulting in a decrease in properties such as heat resistance and thermal expansion coefficient of typical polyimides, or if the aliphatic diamine content is less than 10 parts by mole, elastic recovery may not be achieved, and if the aliphatic diamine content is more than 50 parts by mole, it may be difficult to control the coefficient of friction. The polyimide may be formed by a 1:1 reaction of a dianhydride and a diamine.

[0048] According to one embodiment, the aliphatic diamine may have a molecular weight of 500 g / mol to 5000 g / mol.

[0049] The molecular weight of the aliphatic diamine may preferably be 500 g / mol to 4000 g / mol, 800 g / mol to 4000 g / mol, or 800 g / mol to 3000 g / mol.

[0050] If the molecular weight of the aliphatic diamine is less than 500 g / mol, the elastic recovery rate cannot be expected, and if it exceeds 5000 g / mol, problems with polymerization may occur. When the molecular weight is within this range, the aliphatic diamine may be a long-chain molecule, which can provide a polyimide composition with high elastic recovery rate and copper foil adhesion properties.

[0051] According to one embodiment, the method further includes an organic solvent; and the organic solvent may include at least one selected from the group consisting of dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), cyclohexanone, acetone, diethyl acetate, and m-cresol.

[0052] Preferably, the organic solvent may be dimethylacetamide (DMAc) or cyclohexanone.

[0053] According to one embodiment, the polyimide composition may be a polyamic acid or may be soluble.

[0054] When the polyimide composition contains cyclohexanone as a solvent, a polyamic acid polyimide can be formed, and when it contains dimethylacetamide, a soluble polyimide can be formed.

[0055] According to one embodiment, the solid content may be 15% to 40% by weight.

[0056] Preferably, the solid content may be 25% to 40% by weight.

[0057] The solid content range may be determined by taking into consideration the molecular weight suitable for forming a polyimide film and workability when coating one side of a metal foil, when the polyimide composition is a polyamic acid. If the solid content is less than 15 wt%, unnecessary solvent may be used or the viscosity of the solution may be low, resulting in problems with flow during coating. If the solid content is more than 40 wt%, the viscosity may be too high, resulting in problems with application during coating.

[0058] A method for producing a polyimide composition according to the present invention includes the steps of: introducing an organic solvent into a reactor at 40°C to 60°C; dissolving an aromatic diamine in the organic solvent to prepare a diamine solution; and introducing a dianhydride and an aliphatic diamine into the diamine solution.

[0059] When the temperature of the reactor is within the above range, the reaction may be activated. The method for producing the polyimide composition may be carried out in a reactor at a temperature of 45°C to 55°C for 6 to 24 hours. If the reaction time is less than 6 hours, the reaction may not occur and the product may remain unreacted, while if the reaction time is more than 24 hours, there may be a problem of reduced processability.

[0060] Here, the characteristics of the organic solvent, the dianhydride, the aromatic diamine, and the aliphatic diamine are the same as those described above, and therefore will not be described below.

[0061] According to one embodiment, after the step of adding the aliphatic diamine, the method may further include the step of increasing the temperature of the reactor to 160° C. or more to perform an imidization reaction. The imidization reaction is a step of imidizing a polyamic acid composition, and the imidization reaction can produce a soluble polyamic acid composition.

[0062] The imidization reaction may be carried out for 6 to 12 hours at a temperature of 160° C. or higher. Water can be sufficiently removed within the reaction temperature and reaction time to carry out the imidization.

[0063] The polyimide film according to the present invention is obtained by curing the polyimide composition according to the present invention or the polyimide composition produced by the method for producing a polyimide composition according to the present invention.

[0064] According to one embodiment, the polyimide film may be obtained by coating the polyimide composition on a copper foil, drying, and then curing the coating. The drying may be performed at a temperature of 140°C to 180°C for 1 minute to 20 minutes, and the curing may be performed at a temperature of 250°C to 400°C.

[0065] The drying may be performed in an air atmosphere, and the curing may be performed in a nitrogen atmosphere. If the drying temperature and time are below the above ranges, the solvent may not volatilize sufficiently, and if they are above the above ranges, oxidation may occur in the air atmosphere or processability may be reduced.

[0066] According to an embodiment, the polyimide film may have an elastic recovery rate of 80% or more in a tensile strength range of 1% to 50%.

[0067] The elastic recovery rate refers to the degree to which a film returns to its original length after being stretched over a certain distance. When the elastic recovery rate is 80% or more, the film exhibits a high yield point and elongation. While conventional polyimide films have a yield point of less than 5%, the polyimide film of the present invention has a yield point of 10% to 15%. In this case, the film exhibits excellent flexibility and suppresses the occurrence of cracks due to repeated bending, making it suitable for use as a flexible substrate material.

[0068] According to one embodiment, the polyimide film may have an adhesive strength to a lamination copper foil of 300 gf / cm or more.

[0069] When the adhesive strength of the copper foil is 300 gf / cm or more, excellent adhesive strength of the copper foil is ensured during the formation of a flexible copper clad laminate, and there is an advantage that peeling does not occur and an additional adhesive layer is not required.

[0070] The polyimide film may have a coefficient of thermal expansion (CTE) of 100 ppm / K to 300 ppm / K, and a coefficient of friction of 0.7 or less.

[0071] If the thermal expansion coefficient is outside the above range, there may be a problem with dimensional stability during the manufacturing of flexible copper clad laminates (FCCLs), and if the friction coefficient exceeds 0.7, there may be a problem with reduced processability.

[0072] The polyimide film according to the present invention has high elastic recovery and adhesion to copper foil, and can provide an excellent flexible copper-clad laminate that does not require any additional processing steps.

[0073] The flexible copper-clad laminate according to the present invention comprises a metal foil; and a polyimide film laminated on one or both sides of the metal foil; wherein the polyimide film is the polyimide film according to the present invention.

[0074] The polyimide film may be laminated by coating one or both sides of the metal foil with the polyimide composition of the present invention.

[0075] The coating can be performed by slot die coating, comma coating, reverse comma coating, cast coating, knife coating, roll coating, curtain coating, or dip coating.

[0076] The thickness of the polyimide film may be 5 μm to 100 μm, and the flexible copper clad laminate including the polyimide film having high elastic recovery properties and copper foil adhesive strength properties according to the present invention has the advantage of being suitable for application to FCCL materials, which are core materials for electronic components in the 5G era.

[0077] The present invention will be described in more detail below with reference to examples.

[0078] However, the following examples are for illustrative purposes only and the scope of the present invention is not limited to the following examples. Example 1

[0079] Dimethylacetimide (DMAc) solvent was added to a reactor at 50°C, and then 70 mol% of the aromatic diamine 4,4'-oxydianiline (ODA) was added and dissolved. 100 mol% of the dianhydride 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA) was added to the diamine solution and fully dissolved, and then 30 mol% of the aliphatic diamine polyetheramine (PEA) was added to obtain a polyimide composition. Example 2

[0080] A polyimide composition was obtained in the same manner as in Example 1, except that 75 mol % of ODA and 25 mol % of PEA were added. Example 3

[0081] A polyimide composition was obtained in the same manner as in Example 1, except that 90 mol % of BPADA and 10 mol % of pyromellitic dianhydride (PMDA) were added as dianhydrides.

[0082] The polyimide compositions prepared in Examples 1 to 3 were coated on copper foil and dried at 160°C in an air atmosphere for 10 minutes, and then gradually heated from room temperature to 300°C in a nitrogen atmosphere to be cured to prepare polyimide films.

[0083] The physical properties of the films made from each composition were measured and are shown in Tables 1 and 2.

[0084] (1) Elastic recovery rate The copper foil layer was removed using an iron (II) chloride (FeCl2) solution to obtain a polyimide film. A measurement specimen was then prepared with a length of 150 mm and a width of 10 mm. Then, measurements were made using AND's MCT-1150 with a grip interval of 100 mm, a speed of 50 mm / min, a tension range of 5-50% (5 mm-50 mm), and a load cell of 500 N.

[0085] (2) Coefficient of thermal expansion (CTE) The copper foil layer was removed using an iron(II) chloride (FeCl2) solution to obtain a polyimide film. A measurement specimen was then cut into a length of 4 mm and a width of 50 mm. A tension of 30 N was applied using a Hitachi 7100 to measure the thermal expansion coefficient in the range from 100°C to 150°C.

[0086] (3) Friction coefficient The copper foil layer was removed using an iron (II) chloride (FeCl2) solution to obtain a polyimide film. The resulting film was cut into a length of 100 mm and a width of 50 mm to prepare a measurement specimen. After fixing the specimen to the equipment using a HEIDON Type 10, the section where the sensor stopped was measured.

[0087] (4) Adhesion strength of lamination copper foil The copper foil layer was removed using an iron (II) chloride (FeCl2) solution to obtain a polyimide film. A test specimen was then prepared, measuring 100 mm in length and 10 mm in width. The specimen was then measured using an Instron 3345 at a grip interval of 50 mm and a speed of 50.8 mm / min. [Table 1] [Table 2]

[0088] Table 1 shows the physical properties of the film using the polyamic acid polyimide composition, and Table 2 shows the physical properties of the film using the soluble polyimide composition.

[0089] Referring to Tables 1 and 2, it can be seen that the elastic recovery rate is 80% or more and the adhesive strength of the lamination copper foil is 600 gf / cm or more, and it can be seen that the elastic recovery rate and adhesive strength of the copper foil of the polyimide film according to the present invention are excellent.

[0090] Although the embodiments have been described above, those skilled in the art may apply various technical modifications and variations based on the above description. For example, the described techniques may be performed in a different order from the described method, and / or the components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different manner from the described method, or may be replaced or substituted by other components or equivalents, and still achieve suitable results.

[0091] Therefore, other embodiments, examples, and equivalents of the claims are also within the scope of the following claims.

Claims

1. dianhydrides; and diamine; as a structural unit, The diamines include aromatic diamines and aliphatic diamines. A polyimide composition comprising: The dianhydride is 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA), the aromatic diamine is 4,4'-oxydianiline (ODA); the aliphatic diamine is polyetheramine (PEA); the aliphatic diamine has a molecular weight of 500 g / mol to 5000 g / mol; Relative to 100 mole parts of the dianhydride, the aromatic diamine is 70 to 90 parts by mole, The aliphatic diamine is 10 to 30 parts by mole. Polyimide composition.

2. an organic solvent; the organic solvent includes at least one selected from the group consisting of dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), cyclohexanone, acetone, diethyl acetate, and m-cresol; The polyimide composition of claim 1.

3. The polyimide composition is soluble. The polyimide composition according to claim 2.

4. The solid content is 15% to 40% by weight; The polyimide composition according to claim 2.

5. charging an organic solvent into a reactor at 40°C to 60°C; dissolving an aromatic diamine in the organic solvent to prepare a diamine solution; and adding a dianhydride and an aliphatic diamine to the diamine solution; A method for producing a polyimide composition.

6. After the step of adding the aliphatic diamine, the temperature of the reactor is increased to 160°C or more to carry out an imidization reaction. A method for producing the polyimide composition according to claim 5.

7. A polyimide film obtained by curing the polyimide composition of claim 1.

8. The polyimide film has an elastic recovery rate of 80% or more in a tensile strength range of 1% to 50%. The polyimide film according to claim 7.

9. The polyimide film has an adhesive strength to a lamination copper foil of 300 gf / cm or more. The polyimide film according to claim 7.

10. Metal foil; and a polyimide film laminated on one or both sides of the metal foil; The polyimide film is the polyimide film of claim 7. Flexible copper clad laminate.

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