Black polyimide film and method for producing same

Abstract

The present invention provides a black polyimide film manufactured by imidizing a polyamic acid obtained from a dianhydride monomer and a diamine monomer, the black polyimide film comprising a black pigment containing bituminous coal and perylene black.

Description

Technical Field

[0001] The present invention relates to a black polyimide film and a method for manufacturing the same, and more particularly, to a low-k, low-gloss, and low-transmittance black polyimide film containing a black pigment and a method for manufacturing the same. Background Art

[0002] Polyimide is a general term for polymers having an imide structure, and is generally produced by a condensation reaction of an aromatic anhydride and an aromatic diamine, and has excellent properties such as high heat resistance (which is a property of withstanding temperatures from cryogenic temperatures to high temperatures of 400° C. or higher), electrical insulation, radiation resistance, and chemical resistance, and the like, and therefore it is used in a wide range of fields as a high-tech material and an insulating coating, for example, in the fields of electrical and electronic, semiconductors, displays, automobiles, aviation, and space materials.

[0003] However, since polyimide has the "insoluble, infusible" characteristics of being insoluble in solvents and being unable to be formed by heating, the use of polyimide is limited. Therefore, most polyimides are manufactured by treating polyamic acid (precursor), then heat treating at high temperature and curing the imidization process, and a typical product manufactured in this way is a polyimide film.

[0004] Recently, polyimide is widely used as a cover layer for portable electronic devices and communication devices. The cover layer is used to protect electronic components such as lead frames of printed wiring boards, semiconductor integrated circuits, etc., and requires physical properties such as thinning and miniaturization, and recently, optical properties and safety, portability, visual effects, and concealment of electronic components or mounted components are also required.

[0005] Generally, both matting agent and color additive (for example, pigment or dye) are used to manufacture polyimide film. In conventional manufacturing process, color additive (such as carbon black) is generally included to reduce the transparency of polyimide film, and matting agent such as SiO2 can be added to reduce the glossiness of polyimide film. However, single color additive or matting agent cannot achieve extinction characteristics and reduce transparency. Therefore, conventional manufacturing process needs to use a large amount of color additive and matting agent to give desired characteristics to polyimide film, which not only leads to problems such as difficulties in the processing of additives and poor dispersibility of additives, but also produces high dielectric constant and high dielectric loss factor, so that it is difficult to internalize into 5G electronic devices.

[0006] Therefore, there is a need to develop a black polyimide film for high-speed transmission containing an optimal combination of black pigments to achieve a polyimide film having a low dielectric constant and a low dielectric loss factor, low gloss and transmittance even without adding a matting agent. Summary of the invention

[0007] Technical issues

[0008] An object of the present invention is to provide a black polyimide film comprising a black pigment having a controlled particle size on polyimide, having excellent optical properties such as gloss and transmittance, and having a low permittivity (dielectric constant) and a low dielectric loss factor.

[0009] In addition, another object of the present invention is to provide a method for manufacturing the black polyimide film.

[0010] Furthermore, another object of the present invention is to provide a cover layer including the black polyimide film.

[0011] Furthermore, another object of the present invention is to provide an electronic device for high-speed transmission including the cover layer.

[0012] Solutions to the problem

[0013] Hereinafter, exemplary embodiments of the present invention will be described in more detail in the order of “black polyimide film” and “method of manufacturing black polyimide film” according to the present invention.

[0014] Various modifications can be made in the present invention and various embodiments can be realized, and specific embodiments are described in detail. However, these embodiments are not intended to limit the present invention to specific embodiments, but should be understood to include all modifications, equivalents and alternatives included in the spirit and scope of the present invention.

[0015] The terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates otherwise, singular expressions include plural expressions. In this specification, terms such as "include / comprise" or "have" are intended to specify the presence of features, quantities, steps, operations, components, parts or combinations thereof described in this specification, and it should not be understood as excluding the possibility of existing or adding one or more other features, quantities, steps, operations, components, parts or combinations thereof.

[0016] When amounts, concentrations or other values ​​or parameters herein are given in the form of ranges, preferred ranges or lists of upper desired values ​​and lower desired values, it should be understood to specifically disclose all ranges formed by any pair of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed individually.

[0017] Where numerical ranges are stated herein, it is intended that the endpoints of the range and the scope of the invention within that range are not limited to the specific values ​​stated when defining the range, unless otherwise indicated.

[0018] As used herein, "dianhydride" is intended to include its precursors or derivatives also known as "dianhydrides" or "acid dianhydrides." These products may not be dianhydrides in terminology, but will still react with diamines to form polyamic acid, and the polyamic acid can be converted back to polyimide.

[0019] As used herein, "diamine" is intended to include precursors or derivatives thereof which may not be diamines in terminology but will still react with the dianhydride acid to form a polyamic acid, and the polyamic acid can be converted back to a polyimide.

[0020] In addition, unless otherwise defined, all terms used herein, including technical terms or scientific terms, have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with those in the context of the relevant technology, and unless explicitly defined in this application, they should not be interpreted in an idealized or overly formal sense. Specific details for implementing the present invention will be described below.

[0021] Black polyimide film

[0022] The present invention provides a black polyimide film produced by imidizing a polyamic acid obtained from a dianhydride monomer and a diamine monomer, the black polyimide film comprising: a black pigment containing bituminous coal and perylene black.

[0023] Bituminous coal is also called soft coal, and is black or dark black coal with glassy or resinous luster and high content of volatile matter. In the present invention, bituminous coal may contain up to 20% of volatile matter and about 75% of fixed carbon, but the present invention is not limited thereto. In addition, bituminous coal may contain up to 1% of moisture, up to 0.9% of SO2, and about 7.5% of ash. The polyimide film of the present invention may contain bituminous coal to reduce gloss.

[0024] As the bituminous coal, for example, Mineral Black 325BA (Keystone Filley & Mfg. Co.), Austin Black 325 (Coal Fillers Inc.), or a combination thereof may be used. In an embodiment of the present invention, Austin Black 325 from Coal Fillers Inc. is used.

[0025] Perylene black pigment is one of black organic pigments having a perylene structure in a molecule and exhibiting black color by absorbing light in the wavelength range of visible light.

[0026] Examples of perylene black may include Pigment Black 31 and Pigment Black 32 [each number is identified in the Color Index (CI)], and in addition, may include Pigment Black 31 and Pigment Black 32 of BASF. In one embodiment, using As perylene black.

[0027] In the present invention, based on the gross weight of film, film can include 5 wt % to 30 wt % black pigment.Preferably, the film can include black pigment with 5 wt % or more, 6 wt % or more, 7 wt % or more, 8 wt % or more, 9 wt % or more, 10 wt % or more, 11 wt % or more, 12 wt % or more, 13 wt % or more or 14 wt % or more amount, wherein its upper limit can be 30 wt % or less, 29 wt % or less, 28 wt % or less, 27 wt % or less, 26 wt % or less, 25 wt % or less, 24 wt % or less, 23 wt % or less, 22 wt % or less, 21 wt % or less, 20 wt % or less, 19 wt % or less, 18 wt % or less or 17 wt % or less.When the amount of the black pigment in the film is less than 5 wt %, transmittance increases, and when its amount is greater than 30 wt %, the dispersibility and physical properties of the film deteriorate.

[0028] In the present invention, the membrane may include 3 wt % to 15 wt % of bituminous coal and 2 wt % to 15 wt % of perylene black based on the total weight of the membrane.

[0029] For example, bituminous coal may be included in an amount of 3 wt % or more, 3.5 wt % or more, 4 wt % or more, 4.5 wt % or more, 5 wt % or more, 5.5 wt % or more, 6 wt % or more, or 6.5 wt % or more, wherein the upper limit thereof may be 10 wt % or less, 9 wt % or less, 8 wt % or less, or 7 wt % or less. When bituminous coal is used in excess of 15 wt %, it is not effective in reducing transmittance.

[0030] In addition, in one embodiment, perylene black can be included in an amount of 2 wt % or more, 2.5 wt % or more, 3 wt % or more, 3.5 wt % or more, 4 wt % or more, 4.5 wt % or more, 5 wt % or more, 5.5 wt % or more, 6 wt % or more, 6.5 wt % or more, 7 wt % or more, or 7.5 wt % or more, wherein the upper limit thereof can be 10 wt % or less, 9.5 wt % or less, 9 wt % or less, 8.5 wt % or less, or 8 wt % or less. When the amount of perylene black is less than 2 wt %, it is not effective in reducing transmittance.

[0031] In the present invention, glossiness, transmittance, dielectric constant, and dielectric loss factor can be maintained at low levels by including a black pigment containing bituminous coal and perylene black.

[0032] In the present invention, the average particle size (D50) of the bituminous coal may be 0.5 μm to 10 μm, preferably 1 μm to 8 μm, and more preferably 2 μm to 5 μm. In addition, the bituminous coal may have an average particle size (D10) of 0.5 μm to 2 μm and an average particle size (D90) of 3 μm to 7 μm. The average particle size of the bituminous coal may indicate the average particle size after grinding. When the range of the average particle size (D50) is greater than 10 μm, the surface properties of the film may be damaged, its dispersibility may be deteriorated, and the mechanical properties of the film may be deteriorated.

[0033] In the present invention, the average particle size (D50) of perylene black may be 100 nm to 1,200 nm, specifically 200 nm to 1000 nm, and more specifically 300 nm to 900 nm. When the range of the average particle size (D50) is greater than 1200 nm, the surface properties of the film may be damaged, its dispersibility may be deteriorated, and the mechanical properties of the film may be deteriorated. In addition, perylene black may have an average particle size (D10) of 100 nm to 400 nm and an average particle size (D90) of 500 nm to 2000 nm. The average particle size of perylene black may indicate the average particle size after grinding.

[0034] According to the present invention, a black polyimide film having low gloss, transparency, dielectric constant, and dielectric loss factor is achieved by adjusting the particle size of a black pigment to a suitable size through grinding.

[0035] In the present invention, the dianhydride monomer can be selected from pyromellitic dianhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), diphenyl sulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), bis(3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3' ,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimellitic acid monoester anhydride), p-biphenylenebis(trimellitic acid monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-bis(3, 4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic anhydride, and specifically, it can be selected from pyromellitic anhydride (PMDA), oxydiphthalic anhydride (ODPA), 3,3',4,4'-biphenyl The present invention can be at least one of pyromellitic acid dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA) and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), and more specifically, can be at least one selected from pyromellitic acid dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA) and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA).

[0036] In addition, the diamine monomer may be selected from p-phenylenediamine (PPD), m-phenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4'-oxydiphenylamine (ODA), 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl -4,4'-diaminodiphenylmethane, bis(4-aminophenyl) sulfide, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, -Dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene , 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-di(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,3-bis(4-aminophenyl sulfone)benzene, 1,4-bis(4-aminophenyl sulfone)benzene, 1,3-bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)phenyl ] ketone, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[3-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane At least one of 2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, and specifically, at least one selected from p-phenylenediamine (PPD), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 4,4'-oxydiphenylamine (ODA) and 1,3-bis(4-aminophenoxy)benzene (TPE-R), and more specifically, p-phenylenediamine (PPD) and 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine).

[0037] In one embodiment, the polyamic acid comprises a mixture of dianhydride monomers including pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and diamine monomers including p-phenylenediamine (PPD) and 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine) as polymerized units.

[0038] Here, pyromellitic dianhydride (PMDA) may be included in an amount of 20 mol% or more to 80 mol% or less of the total dianhydride monomer component, and preferably may be included in an amount of 22 mol% or more, 24 mol% or more, 26 mol% or more, 28 mol% or more, 30 mol% or more, 31 mol% or more, 32 mol% or more, 33 mol% or more, 34 mol% or more, 35 mol% or more, 36 mol% or more, 37 mol% or more, 38 mol% or more, 39 mol% or more, or 40 mol% or more, wherein the upper limit thereof is It may be 80 mol% or less, 75 mol% or less, 70 mol% or less, 65 mol% or less, 60 mol% or less, 55 mol% or less, 50 mol% or less, 48 ​​mol% or less, 46 mol% or less, 44 mol% or less, 42 mol% or less, 40 mol% or less, 39 mol% or less, 38 mol% or less, 37 mol% or less, 36 mol% or less, 35 mol% or less, 34 mol% or less, 33 mol% or less, 32 mol% or less, 31 mol% or less, or 30 mol% or less.

[0039] Furthermore, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) may be contained in an amount of 10 mol% or more to 50 mol% or less of the total dianhydride monomer component, and preferably may be contained in an amount of 10 mol% or more, 15 mol% or more, 20 mol% or more, 22 mol% or more, 24 mol% or more, 26 mol% or more, 28 mol% or more, 30 mol% or more, 31 mol% or more, 32 mol% or more, 33 mol% or more, 34 mol% or more, 35 mol% or more, 36 mol% or more, 37 mol% or more, 38 mol% or more, 39 mol% or more, 40 mol% or more, 41 mol% or more, 42 mol% or more, 43 mol% or more, 44 mol% or more, 45 mol% or more, 46 mol% or more, 47 mol% or more, 48 mol% or more, 49 mol% or more, 50 mol% or more, 51 mol% or more, 52 mol% or more, 53 mol% or more, 54 mol% or more, 55 mol% or more, 56 mol% or more, 57 mol% or more, % or more, 38 mol% or more, 39 mol% or more, or 40 mol% or more is included, wherein the upper limit thereof may be 50 mol% or less, 48 ​​mol% or less, 46 mol% or less, 44 mol% or less, 42 mol% or less, 40 mol% or less, 39 mol% or less, 38 mol% or less, 37 mol% or less, 36 mol% or less, 35 mol% or less, 34 mol% or less, 33 mol% or less, 32 mol% or less, 31 mol% or less, or 30 mol% or less.

[0040] Furthermore, 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) or 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) may be contained in an amount of 10 mol% or more to 50 mol% or less of the total dianhydride monomer component, and preferably may be contained in an amount of 10 mol% or more, 15 mol% or more, 20 mol% or more, 22 mol% or more, 24 mol% or more, 26 mol% or more, 28 mol% or more, 30 mol% or more, 31 mol% or more, 32 mol% or more, 33 mol% or more, 34 mol% or more, 35 mol% or more. % or more, 36 mol% or more, 37 mol% or more, 38 mol% or more, 39 mol% or more, or 40 mol% or more is included, wherein the upper limit thereof may be 50 mol% or less, 48 ​​mol% or less, 46 mol% or less, 44 mol% or less, 42 mol% or less, 40 mol% or less, 39 mol% or less, 38 mol% or less, 37 mol% or less, 36 mol% or less, 35 mol% or less, 34 mol% or less, 33 mol% or less, 32 mol% or less, 31 mol% or less, or 30 mol% or less.

[0041] In the present invention, the polyamic acid can be prepared by appropriately adjusting the amount of the dianhydride component within the range of 100 mol% of the dianhydride component in total, wherein the dianhydride component includes: pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA).

[0042] In one embodiment, the dianhydride monomer may include 20 mol% to 80 mol% of pyromellitic dianhydride (PMDA); 10 mol% to 50 mol% of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) or 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA); and 10 mol% to 50 mol% of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA).

[0043] Furthermore, p-phenylenediamine (PPD) may be contained in an amount of 10 mol% or more to 80 mol% or less of the total diamine monomer component, and preferably may be contained in an amount of 10 mol% or more, 15 mol% or more, 20 mol% or more, 25 mol% or more, 30 mol% or more, 35 mol% or more, 40 mol% or more, 42 mol% or more, 44 mol% or more, 46 mol% or more, 48 mol% or more, 50 mol% or more, 52 mol% or more, 54 mol% or more, 56 mol% or more, 58 mol% or more, 60 mol% or more, 62 mol% or more, % or more, 64 mol% or more, 66 mol% or more, 68 mol% or more, 70 mol% or more, 72 mol% or more, 74 mol% or more, or 76 mol% or more is included, wherein the upper limit thereof may be 80 mol% or less, 78 mol% or less, 76 mol% or less, 74 mol% or less, 72 mol% or less, 70 mol% or less, 68 mol% or less, 66 mol% or less, 64 mol% or less, 62 mol% or less, 60 mol% or less, 55 mol% or less, 50 mol% or less, or 45 mol% or less.

[0044] Furthermore, 2,2′-dimethyl-4,4′-diaminobiphenyl (m-tolidine) may be contained in an amount of 20 mol% or more to 90 mol% or less of the total diamine monomer component, and preferably may be contained in an amount of 22 mol% or more, 24 mol% or more, 26 mol% or more, 28 mol% or more, 30 mol% or more, 31 mol% or more, 32 mol% or more, 33 mol% or more, 34 mol% or more, 35 mol% or more, 36 mol% or more, 37 mol% or more, 38 mol% or more, 39 mol% or more, or 40 mol% or more, wherein the upper limit thereof may be 90 mol% or less, 88 mol% or less, 86 mol% or less, 84 mol% or less. % or less, 82 mol % or less, 80 mol % or less, 78 mol % or less, 76 mol % or less, 74 mol % or less, 72 mol % or less, 70 mol % or less, 68 mol % or less, 66 mol % or less, 64 mol % or less, 62 mol % or less, 60 mol % or less, 58 mol % or less, 56 mol % or less, 54 mol % or less, 52 mol % or less, 50 mol % or less, 48 ​​mol % or less, 46 mol % or less, 44 mol % or less, 42 mol % or less, 40 mol % or less, 39 mol % or less, 38 mol % or less, 37 mol % or less, 36 mol % or less, or 35 mol % or less.

[0045] In the present invention, the polyamic acid may be prepared by appropriately adjusting the amount of each diamine monomer component including p-phenylenediamine (PPD) and 2,2′-dimethyl-4,4′-diaminobiphenyl (m-tolidine) within a range where the total diamine monomer component is 100 mol %.

[0046] In one embodiment, the diamine monomer comprises 10 mol % to 80 mol % of p-phenylenediamine (PPD); and 20 mol % to 90 mol % of 2,2′-dimethyl-4,4′-diaminobiphenyl (m-tolidine).

[0047] In the present invention, the molar ratio of the diamine monomer to the dianhydride monomer may be 0.5 equivalent to 2 equivalents. Specifically, the molar ratio may be 0.8 equivalent to 1.5 equivalents. When the molar ratio is less than 0.5 equivalent or greater than 2 equivalents, the polyimide finally formed has a very low molecular weight, and therefore has a problem of very poor physical and chemical properties.

[0048] The thickness of the black polyimide film according to the present invention may be 3 μm to 100 μm, specifically 4 μm to 90 μm, more specifically 5 μm to 80 μm, and more specifically 5.5 μm to 50 μm. The thickness of the film is not particularly limited as long as the film can be applied flexibly, and the thickness can be adjusted in consideration of mechanical strength, handling, productivity, etc.

[0049] The black polyimide film of the present invention may have a transmittance of 0.2% or less in a visible light region, a glossiness (60°) of 50 or less, a dielectric constant (Dk) of 4.0 or less, and a dielectric loss factor (Df) of 0.01 or less.

[0050] In addition, the black polyimide film of the present invention may have a transmittance of 0.1% or less in a visible light region, a glossiness (60°) of 40 or less, a dielectric constant (Dk) of 3.7 or less, and a dielectric loss factor (Df) of 0.01 or less.

[0051] In addition, the black polyimide film of the present invention can simultaneously satisfy the following conditions: transmittance in the visible light region is 0.2% or less, glossiness (60°) is 50 or less, dielectric constant (Dk) is 4.0 or less, and dielectric loss factor (Df) is 0.01 or less.

[0052] In addition, the black polyimide film of the present invention can simultaneously satisfy the following conditions: transmittance in the visible light region is 0.1% or less, glossiness (60°) is 40 or less, dielectric constant (Dk) is 3.7 or less, and dielectric loss factor (Df) is 0.01 or less.

[0053] The dielectric constant of the black polyimide film according to the present invention at 10 GHz can be, for example, 4.0 or less, preferably 3.9 or less, more preferably 3.7 or less, wherein its lower limit can be at least 3.0 or greater. It can be understood that when considering that the polyimide film has the highest engineering properties, it shows an ideal dielectric constant as an insulator.

[0054] In addition, the dielectric loss factor (Df) of the black polyimide film according to the present invention at 10GHz can be, for example, 0.01 or less, preferably 0.0099 or less, wherein its lower limit can be at least 0.005 or greater. The term "dielectric loss factor" refers to the force dissipated by a dielectric (or insulator) when the friction between molecules interferes with the molecular motion caused by an alternating electric field, and the value of the dielectric loss factor is generally used as an index indicating the ease of charge loss (dielectric loss). The higher the dielectric loss factor, the easier the charge is to lose, and conversely, the lower the dielectric loss factor, the more difficult the charge is to lose. In other words, the dielectric loss factor is a measure of power loss. Since the dielectric loss factor is low, the signal transmission delay caused by power loss can be mitigated, and the communication speed can be kept high.

[0055] Therefore, the polyimide film of the present invention has an advantage in that insulation is easily maintained even in an electronic device for high-speed transmission operating at a high frequency of gigahertz (eg, 10 GHz or higher).

[0056] Furthermore, as an example, the transmittance of the black polyimide film according to the present invention may be 0.2% or less, and preferably 0.10 or less. It is understood that the film has physical properties suitable for use as a cover layer.

[0057] In addition, the glossiness (60°) of the black polyimide film according to the present invention may be 50 or less, preferably 45 or less, more preferably 40 or less, and even more preferably 37 or less. If the glossiness exceeds 50, there may be problems of having poor visual beauty and poor covering function.

[0058] Therefore, a polyimide film that satisfies all of the dielectric constant, dielectric loss factor, glossiness and transmittance can be used as an insulating layer for a covering layer, and even when the manufactured covering layer is used as an electrical signal transmission circuit that transmits signals at a high frequency of 10 GHz or more, insulation stability can be ensured and signal transmission delay can be minimized.

[0059] The black polyimide film of the present invention which satisfies the following conditions at the same time is a new black polyimide film which has been unknown so far: the transmittance in the visible light region is 0.2% or less, the glossiness (60°) is 50 or less, the dielectric constant (Dk) is 4.0 or less, and the dielectric loss factor (Df) is 0.01 or less.

[0060] Method for producing black polyimide film of the present invention

[0061] The present invention provides a method for manufacturing a black polyimide film comprising:

[0062] (1) polymerizing a polyamic acid solution from at least one dianhydride monomer and at least one diamine monomer;

[0063] (2) preparing a polyimide precursor composition by mixing a polyamic acid solution with a black pigment comprising bituminous coal and perylene black; and

[0064] (3) The polyimide precursor composition is imidized by forming a film on a support and heat-treating the film.

[0065] In the method for producing a black polyimide film, the "dianhydride monomer" and the "diamine monomer" are the same as described above, and the method for producing a black polyimide film of the present invention may be a method for forming a polyimide film in general.

[0066] In one embodiment, in step (1), polyamic acid solution is obtained by reacting dianhydride and diamine using an organic solvent. Here, the solvent is not particularly limited, as long as the polyamic acid can be dissolved, but as an example, it can be a non-protonic polar solvent. Preferably, N-methyl-pyrrolidone (NMP), N, N'-dimethylformamide (DMF), N, N'-diethylformamide (DEF), N, N'-dimethylacetamide (DMAc), dimethylpropionamide (DMPA), N, N-diethylacetamide (685-91-6, DEAc), 3-methoxy-N, N-dimethylpropionamide (53185-52-7, KJCMPA) etc. can be used alone or in combination, but N-methyl-pyrrolidone (NMP) can be used most preferably.

[0067] In the present invention, the weight average molecular weight of the polyamic acid solution of the present invention can be 100,000g / mol to 300,000g / mol. The lower limit of the weight average molecular weight can be 100,000g / mol or more, 120,000g / mol or more, 150,000g / mol or more, or 200,000g / mol or more, and the upper limit of the weight average molecular weight can be 300,000g / mol or less, 280,000g / mol or less, 270,000g / mol or less, 260,000g / mol or less, or 250,000g / mol or less.

[0068] In the present invention, when adding substantially equimolar amounts of diamine and dianhydride, the weight of the added monomers in the total polyamic acid solution is referred to as solid content, and the solid content of the polyamic acid solution can be 5 wt % to 30 wt %. The lower limit of the weight percentage (%) of the solid content can be 5 wt % or more, 8 wt % or more, 9 wt % or more, 10 wt % or more, 15 wt % or more, 20 wt % or more, 21 wt % or more, 22 wt % or more, 23 wt % or more, 24 wt % or more, 25 wt % or more, 26 wt % or more, 27 wt % or more, 28 wt % or more, or 29 wt % or more, and the upper limit of the weight percentage (%) of the solid content can be 29 wt % or less, 27 wt % or less, 25 wt % or less, 23 wt % or less, 21 wt % or less, 20 wt % or less, 19 wt % or less, or 18 wt % or less. By adjusting the solid content of the polyamic acid composition, it is possible to control the increase in viscosity and shorten the processing time during the curing process.

[0069] In the present invention, the viscosity of the polyamic acid solution may be in the range of 20,000 cP to 400,000 cP, which is a viscosity at a temperature of 23° C. and a viscosity of 1 second. -1 The viscosity may be measured at a shear rate of 1 / sec, a temperature of 23°C, and a plate spacing of 1 mm. The present invention may provide a precursor composition having excellent processability by adjusting the viscosity range.

[0070] In step (2), bituminous coal and perylene black contained in the polyimide precursor composition are ground through a grinding process to adjust the particle size, thereby increasing the dispersion so that the components are uniformly mixed when mixed with the polyamic acid solution, while reducing the gloss, transmittance, dielectric constant and dielectric loss factor.

[0071] In this regard, the manufacturing method may further include, before step (2), grinding with a grinder to separately prepare bituminous coal having an average particle size (D50) of 0.5 μm to 10 μm and perylene black having an average particle size (D50) of 100 nm to 1200 nm.

[0072] In one embodiment, the grinding process can be carried out using a bead mill with beads having a particle size of 1.0 mm to 2.0 mm to prepare bituminous coal and / or perylene black each having a particle size within the above range, and the grinding process can be carried out by treating bituminous coal and perylene black separately or by treating bituminous coal and perylene black together. The stirring speed and grinding time during the grinding process can be appropriately adjusted according to the desired particle size, and there is no particular restriction. In addition, bituminous coal and / or perylene black each having a particle size within the above range can be prepared by grinding using a bead mill with beads having a particle size of 0.8 mm to 1.5 mm.

[0073] In addition, in step (2), the black pigment is obtained by dispersing bituminous coal and perylene black in an organic solvent, wherein the organic solvent may be at least one selected from N-methylformamide, N,N'-dimethylformamide (DMF), N-methylformanilide, N,N'-dimethylacetamide (DMAC), N-methyl-pyrrolidone (NMP), propylene glycol methyl ether acetate (PGMEA), ethyl glycol acetate, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether and acetylacetone, and preferably may be at least one selected from N,N'-dimethylformamide (DMF), N,N'-dimethylacetamide (DMAC), N-methyl-pyrrolidone (NMP) and propylene glycol methyl ether acetate (PGMEA).

[0074] In the present invention, step (3) may be performed by casting the polyimide precursor composition prepared in step (2) on a support and drying to form a gel film, and then imidizing the gel film to form a black polyimide film.

[0075] The formation of the gel film can be carried out by casting the polyimide precursor composition in the form of a film on a support (e.g., aluminum foil, an endless stainless steel belt, a stainless steel cylinder, etc.), and then drying the precursor composition on the support at 50°C to 200°C, specifically at a variable temperature ranging from 80°C to 150°C.

[0076] Imidization is performed by heat treatment, wherein the heat treatment can be performed at a variable temperature ranging from 50°C to 500°C, specifically 150°C to 500°C to remove remaining water, residual solvent, etc., and imidize almost all remaining amic acid groups, thereby manufacturing the black polyimide film of the present invention. In some cases, the polyimide film obtained as above can be heated at a temperature of 400°C to 650°C and finished for 5 seconds to 400 seconds to further solidify the polyimide film, and the polyimide film can be treated under a certain tension to relieve the internal stress that may remain in the obtained polyimide film.

[0077] The present invention provides a cover layer comprising the black polyimide film and an electronic device for high-speed transmission comprising the cover layer.

[0078] Advantageous Effects of the Invention

[0079] The black polyimide film of the present invention includes a black pigment including a combination of bituminous coal and perylene black to have excellent optical characteristics such as low gloss and low transmittance, and has excellent low dielectric characteristics due to a low dielectric constant and a low dielectric loss factor. DETAILED DESCRIPTION

[0080] The following examples are presented to help understand the present invention. The following examples are provided only for easier understanding of the present invention, but the content of the present invention is not limited to these examples.

[0081] <Example>

[0082] Example 1: Preparation of polyimide precursor composition

[0083] Example 1-1.

[0084] As the polyamic acid solution polymerization process, 408.62g of dimethylformamide (DMF) was added as a solvent to a 500mL reaction vessel under a nitrogen atmosphere. The temperature was set to 25°C, PPD (66mol%) and m-tolidine (34mol%) were added as diamine monomers, which were stirred for about 30 minutes to determine that the monomers were dissolved, and then PMDA (35mol%), BTDA (33mol%) and BPDA (32mol%) were added as dianhydride monomers, and stirred to react until there was no change in viscosity, thereby obtaining a polyamic acid solution.

[0085] A polyimide precursor composition was prepared by mixing the prepared polyamic acid solution with a black pigment including bituminous coal (6.6 wt %) and perylene black (3.5 wt %) dispersed in an organic solvent. The black pigment was contained in the polyimide precursor composition in a total of 10.1 wt %.

[0086] Example 1-2

[0087] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment comprising bituminous coal (6.6 wt %) and perylene black (4.5 wt %) was used instead of the black pigment comprising bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 11.1 wt %.

[0088] Examples 1-3

[0089] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment comprising bituminous coal (6.6 wt %) and perylene black (5.5 wt %) was used instead of the black pigment comprising bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 12.1 wt %.

[0090] Examples 1-4

[0091] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment comprising bituminous coal (6.6 wt %) and perylene black (6.5 wt %) was used instead of the black pigment comprising bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 13.1 wt %.

[0092] The components and amounts of the polyimide precursor compositions prepared according to Examples 1-1 to 1-4 are summarized in the following Table 1 (herein, the weight percentage (wt %) of the black pigment refers to the amount (content) in the polyimide precursor composition).

[0093] [Table 1]

[0094]

[0095] Comparative Example 1: Preparation of polyimide precursor composition

[0096] Comparative Example 1-1 (excluding black pigment)

[0097] As the polyamic acid solution polymerization process, 408.62g of dimethylformamide (DMF) was added as a solvent to a 500mL reaction vessel under a nitrogen atmosphere. The temperature was set to 25°C, PPD (66mol%) and m-tolidine (34mol%) were added as diamine monomers, which were stirred for about 30 minutes to determine that the monomers were dissolved, and then PMDA (35mol%), BTDA (33mol%) and BPDA (32mol%) were added as dianhydride monomers, and stirred to react until there was no change in viscosity, thereby obtaining a polyamic acid solution.

[0098] Comparative Example 1-2 (containing only bituminous coal as black pigment)

[0099] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment containing only bituminous coal (6.6 wt %) was used instead of the black pigment containing bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 6.6 wt %.

[0100] Comparative Examples 1-3 (Containing Bituminous Coal and Carbon Black as Black Pigments)

[0101] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment comprising bituminous coal (6.6 wt %) and carbon black (2.5 wt %) was used instead of the black pigment comprising bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 9.1 wt %.

[0102] Comparative Example 1-4 (Containing only perylene black as black pigment)

[0103] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment containing only perylene black (2.5 wt %) was used instead of the black pigment containing bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in an amount of 2.5 wt % in total.

[0104] Comparative Example 1-5 (Containing only perylene black as black pigment)

[0105] A polyimide precursor composition was prepared in the same manner as in Example 1-1 above, except that a black pigment containing only perylene black (4.5 wt %) was used instead of the black pigment containing bituminous coal (6.6 wt %) and perylene black (3.5 wt %) of Example 1-1. The black pigment was contained in the polyimide precursor composition in a total of 4.5 wt %.

[0106] The components and amounts of the polyimide precursor compositions prepared according to Comparative Examples 1-1 to 1-5 are summarized in Table 2 below.

[0107] [Table 2]

[0108]

[0109] Example 2: Preparation of black polyimide film

[0110] Example 2-1

[0111] The polyimide precursor composition prepared in Example 1-1 was cast on a SUS plate (100SA, Sandvik) to a thickness of 70 μm using a doctor blade and dried at a temperature range of 100° C. to 200° C. Next, the film was peeled off from the SUS plate, fixed to a pin frame, and transferred to a high-temperature tenter. The film was heated from 200° C. to 600° C. in a high-temperature tenter, cooled to 25° C., and then separated from the pin frame, thereby manufacturing a black polyimide film having a thickness of 12.5 μm ± 0.5 μm containing 6.6 wt % of bituminous coal and 3.5 wt % of perylene black based on the total weight of the polyimide film.

[0112] Example 2-2

[0113] A black polyimide film including 6.6 wt % of bituminous coal and 4.5 wt % of perylene black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Example 1-2 was used instead of the polyimide precursor composition in Example 1-1.

[0114] Example 2-3

[0115] A black polyimide film including 6.6 wt % of bituminous coal and 5.5 wt % of perylene black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Example 1-3 was used instead of the polyimide precursor composition in Example 1-1.

[0116] Embodiment 2-4

[0117] A black polyimide film including 6.6 wt % of bituminous coal and 6.5 wt % of perylene black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Example 1-4 was used instead of the polyimide precursor composition in Example 1-1.

[0118] Comparative Example 2: Preparation of black polyimide film

[0119] Comparative Example 2-1 (excluding black pigment)

[0120] A polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Comparative Example 1-1 was used instead of the polyimide precursor composition of Example 1-1. The polyimide film of Comparative Example 2-1 did not include a black pigment.

[0121] Comparative Example 2-2 (containing only bituminous coal as black pigment)

[0122] A black polyimide film including 6.6 wt % of bituminous coal based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Comparative Example 1-2 was used instead of the polyimide precursor composition of Example 1-1.

[0123] Comparative Example 2-3 (Containing bituminous coal and carbon black as black pigments)

[0124] A black polyimide film containing 6.6 wt % of bituminous coal and 2.5 wt % of carbon black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Comparative Example 1-3 was used instead of the polyimide precursor composition of Example 1-1.

[0125] Comparative Example 2-4 (Containing only perylene black as black pigment)

[0126] A black polyimide film including 2.5 wt % of perylene black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Comparative Example 1-4 was used instead of the polyimide precursor composition of Example 1-1.

[0127] Comparative Example 2-5 (Containing only perylene black as black pigment)

[0128] A black polyimide film including 4.5 wt % of perylene black based on the total weight of the polyimide film was manufactured in the same manner as in Example 2-1 above, except that the polyimide precursor composition prepared in Comparative Example 1-5 was used instead of the polyimide precursor composition of Example 1-1.

[0129] <Experimental example>

[0130] Experimental Example 1. Glossiness Evaluation

[0131] According to the ASTM D523 method, the glossiness was measured at an angle of 60 degrees using a gloss meter (PG-IIM, NIPPON DENSHOKU), and the results are shown in Table 3 below.

[0132] Experimental Example 2. Transmittance Evaluation

[0133] According to the ASTM D1003 method, the transmittance was measured in the visible light region using a transmittance testing device (ColorQuesetXE, HunterLab), and the results thereof are shown in Table 3 below.

[0134] Experimental Example 3. Dielectric Constant (Dk) Evaluation

[0135] The dielectric constant at 10 GHz was measured using a SPDR meter from Keysight, and the results are shown in Table 3 below.

[0136] Experimental Example 4. Dielectric loss factor (Df)

[0137] The dielectric loss factor (Df) was measured using an Agilent 4294A impedance analyzer by leaving the flexible metal clad laminate for 72 hours, and the results are shown in Table 3 below.

[0138] [Table 3]

[0139]

[0140]

[0141] Referring to Table 3, the black polyimide film of the present invention satisfies all of the following conditions simultaneously: transmittance of 0.1% or less, glossiness of 50 or less, dielectric constant of 4.0 or less, and dielectric loss factor of 0.01 or less.

[0142] However, Comparative Example 2-1 containing no black pigment and Comparative Examples 2-4 and 2-5 containing only perylene black as a black pigment showed very high transmittance and glossiness, and Comparative Example 2-2 containing only bituminous coal as a black pigment showed very high transmittance of 2% or more.

[0143] Furthermore, Comparative Examples 2-3 including bituminous coal and carbon black as black pigments showed remarkably high dielectric constants and dielectric loss factors of 4.61 and 0.03082, respectively.

[0144] In this specification, details that can be fully recognized and inferred by those skilled in the art in the field of the present invention are omitted, and in addition to the specific embodiments described in this specification, various modifications can be made within the scope of not changing the technical spirit or basic configuration of the present invention. Therefore, the present invention can be practiced in other ways that can be understood by those skilled in the art in addition to the specific description and illustration herein.

Claims

1. A black polyimide film produced by imidizing a polyamic acid obtained from a dianhydride monomer and a diamine monomer, the black polyimide film comprising: a black pigment containing bituminous coal and perylene black. 2 . The black polyimide film according to claim 1 , wherein the film comprises 3 wt % to 15 wt % of bituminous coal and 2 wt % to 15 wt % of perylene black based on the total weight of the film. 3 . The black polyimide film according to claim 1 , wherein the film comprises 5 to 10 wt % of bituminous coal and 3 to 10 wt % of perylene black based on the total weight of the film. 4 . The black polyimide film according to claim 1 , wherein the average particle size (D50) of the bituminous coal is 0.5 μm to 10 μm. The black polyimide film according to claim 1 , wherein the average particle size (D50) of the perylene black is 100 nm to 1200 nm.

6. The black polyimide film according to claim 1, wherein the dianhydride monomer is at least one selected from the group consisting of pyromellitic dianhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), diphenyl sulfone-3,4,3',4'-tetracarboxylic dianhydride (DSDA), bis(3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3',4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), bis(3,4-dicarboxyphenyl) [0043] The present invention also includes 1,2-bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimellitic acid monoester anhydride), p-biphenylenebis(trimellitic acid monoester anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic acid dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride.

7. The black polyimide film according to claim 1, wherein the diamine monomer is at least one selected from the group consisting of p-phenylenediamine (PPD), m-phenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 4,4'-oxydianiline (ODA), 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy- 4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino- 4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene (3-aminophenyl)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,4-bis(3-aminophenoxy)benzene (TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-bis(4-phenylphenoxy)benzophenone, 1,3-bis(3-aminophenyl sulfide)benzene, 1,3-bis(4-aminophenyl sulfide)benzene, 1,4-bis(4-aminophenyl sulfide)benzene, 1,3-bis(3-aminophenyl sulfone)benzene, 1,3-bis(4-aminophenyl sulfone)benzene, 1,4-bis(4-aminophenyl sulfone)benzene, 1,3-Bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl] ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]ketone, bis[3-(3-aminophenoxy)phenyl]thioether, bis[3-(4-aminophenoxy)phenyl]thioether, bis[4-(3-aminophenoxy)phenyl]thioether, bis[4-(4-aminophenoxy)phenyl]thioether, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3 bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane )phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane.

8. The black polyimide film according to claim 1, wherein the dianhydride monomer is at least one selected from pyromellitic dianhydride (PMDA), oxydiphthalic dianhydride (ODPA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), and The diamine monomer is at least one selected from p-phenylenediamine (PPD), 2,2′-dimethyl-4,4′-diaminobiphenyl (m-tolidine), 4,4′-oxydiphenylamine (ODA), and 1,3-bis(4-aminophenoxy)benzene (TPE-R).

9. The black polyimide film according to claim 1, wherein the dianhydride monomer comprises 20 mol % to 80 mol % of pyromellitic dianhydride (PMDA); 10 mol % to 50 mol % of 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) or 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA); and 10 mol % to 50 mol % of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), and The diamine monomer includes 10 mol % to 80 mol % of p-phenylenediamine (PPD); and 20 mol % to 90 mol % of 2,2′-dimethyl-4,4′-diaminobiphenyl (m-tolidine). 10 . The black polyimide film according to claim 1 , wherein the film has a thickness of 5 μm to 100 μm.

11. The black polyimide film according to claim 1, wherein The transmittance in the visible light region is 0.2% or less, Gloss (60°) is 50 or less, A dielectric constant (Dk) of 4.0 or less, and The dielectric loss factor (Df) is 0.01 or less.

12. A method for producing a black polyimide film, comprising: (1) polymerizing a polyamic acid solution from at least one dianhydride monomer and at least one diamine monomer; (2) preparing a polyimide precursor composition by mixing the polyamic acid solution with a black pigment comprising bituminous coal and perylene black; as well as (3) imidizing the polyimide precursor composition by forming a film on a support and heat-treating the film.

13. The manufacturing method according to claim 12, comprising, before step (2), grinding with a grinder to prepare bituminous coal with an average particle size (D50) of 0.5 μm to 10 μm and perylene black with an average particle size (D50) of 100 nm to 1200 nm respectively.

14. The production method according to claim 12, wherein in step (2), the black pigment is obtained by dispersing bituminous coal and perylene black in an organic solvent.

15. The production method according to claim 14, wherein the organic solvent is at least one selected from the group consisting of N-methylformamide, N,N'-dimethylformamide (DMF), N-methylformanilide, N,N'-dimethylacetamide (DMAC), N-methyl-pyrrolidone (NMP), propylene glycol methyl ether acetate (PGMEA), ethyl glycol acetate, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether and acetylacetone.

16. A cover layer comprising the black polyimide film according to any one of claims 1 to 11.

17. An electronic device for high-speed transmission, comprising the cover layer according to claim 16.

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