Ultrathin polyimide film and composition for preparing same

Abstract

The present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, wherein the polyimide film has a thickness of 1 to 10 um, and a thickness relative deviation (R difference) of 25% or less, where the thickness relative deviation (R difference) is a value calculated by dividing the thickness deviation by the average thickness of the film and multiplying the result by 100(%), and the thickness deviation is a difference between the maximum thickness value and the minimum thickness value among the thickness values measured using a film tester along the width direction of the film.

Description

Ultrathin polyimide film and composition for manufacturing the same

[0001] The present invention relates to an ultrathin polyimide film and a composition for manufacturing the same.

[0002] Generally, polyimide (PI) resin refers to a high heat-resistant resin produced by solution polymerizing an aromatic acid dianhydride with an aromatic diamine or an aromatic diisocyanate to produce a polyamic acid derivative, and then closure dehydrating it at high temperature to produce an imid.

[0003] Polyimide resins are widely used in the fields of electrical and electronic materials, aerospace, and telecommunications due to their excellent mechanical, thermal, and chemical stability. In particular, because polyimide resins possess high insulation performance, they are widely applied in printed circuit boards and other applications as components and parts requiring high reliability.

[0004] Recently, as electronic products continue to become smaller, lighter, and more dense, the need for thinner materials is increasing.

[0005] Meanwhile, as thin films are significantly affected by even minute variations in process conditions, ensuring thickness uniformity has emerged as a critical technical challenge. In particular, since electrical, mechanical, and appearance properties of thin films are greatly influenced by thickness variations, there is a continuously increasing need for process control and uniformity improvement technologies to minimize thickness deviations in thin film manufacturing processes.

[0006] Accordingly, there is a need to develop thin polyimide films that have low thickness variation (i.e., excellent thickness uniformity).

[0007] The present invention aims to provide a polyimide film having a thickness relative deviation (R-difference) of 25% or less, a thickness of 10 μm or less, and a thickness relative standard deviation of 6% or less, and a composition for manufacturing the same.

[0008] The present invention aims to provide an ultrathin polyimide film with excellent dielectric breakdown voltage (BDV) and improved appearance quality by minimizing thickness variation, thickness relative variation (R difference), and thickness relative standard variation to enhance thickness precision, and a composition for manufacturing the same.

[0009] The present invention aims to provide a polyimide film that is thin, wide, and easy to wind into a long coil while providing high dimensional stability, and a composition for manufacturing the same.

[0010] The present invention aims to provide a polyimide film having an absolute value of the difference in loop stiffness between the machine transport direction (MD) and the width direction (TD) within a specific range, and a composition for manufacturing the same.

[0011] The present invention aims to provide a polyimide film having an absolute value of the difference in initiation tear strength between the machine transport direction (MD) and the width direction (TD) within a specific range, and a composition for manufacturing the same.

[0012] The present invention aims to provide a polyimide film having an absolute value of the difference in propagation tear strength between the machine transport direction (MD) and the width direction (TD) within a specific range, and a composition for manufacturing the same.

[0013] In addition, the present invention aims to provide a flexible circuit board comprising the polyimide film.

[0014] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be illustrated and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0015] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0016] Where in this specification, when a quantity, concentration, or other value or parameter is given as an enumeration of a range, a preferred range, a preferred upper limit, and a preferred lower limit, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value are specifically disclosed, regardless of whether the range is disclosed separately.

[0017] Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, the range and the scope of the invention within that range are not intended to be limited to the specific value mentioned when defining the range.

[0018] In this specification, "dianhydride" is intended to include its precursors or derivatives, which are also referred to as "dianhydrides," "dianhydric acids," or "acid dianhydrides." Although these may not technically be dianhydrides, they will nevertheless react with a diamine to form a polyamic acid, which can then be converted into a polyimide.

[0019] In this specification, "diamine" is intended to include its precursors or derivatives, which may not technically be diamines but nevertheless will react with dianhydrides to form polyamic acids, which can then be converted into polyimides.

[0020] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application. Specific details for the implementation of the above invention are described below.

[0021] The present invention relates to an ultrathin polyimide film and a composition for manufacturing the same.

[0022] polyimide film

[0023] The present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, having a relative thickness deviation (R difference) of 25% or less and a thickness of 1 to 10 μm. Here, the relative thickness deviation (R difference) is a value calculated by dividing the thickness deviation by the average thickness of the film and multiplying by 100 (%), and the thickness deviation refers to the difference between the maximum thickness value and the minimum thickness value among the thicknesses measured using a film tester (FUJIWORK Film Tester) along the width direction of the film.

[0024] Specifically, the upper limit of the above thickness relative deviation (R difference) may be 25% or less, 24.95% or less, 24.90% or less, 24.85% or less, or 24.80% or less, and the lower limit may be 1% or more, 5% or more, or 10% or more, but is not limited thereto. Here, if the above thickness relative deviation (R difference) exceeds 25%, it is undesirable as the dielectric breakdown voltage (BDV) and appearance quality may deteriorate.

[0025] Here, the thickness of the polyimide film was measured using a film tester (FUJIWORK Film Tester) (Resolution 0.01㎛), and the thickness relative deviation (R-difference), thickness relative standard deviation, and thickness deviation were calculated based on the measured values.

[0026] In addition, the relative standard deviation of the thickness of the polyimide film may be 6% or less, preferably 5.98% or less, 5.96% or less, 5.94% or less, 5.92% or less, or 5.90% or less, and the lower limit may be 0.1% or more, 1% or more, or 3% or more, but is not limited thereto. Here, the relative standard deviation of thickness refers to a value calculated by dividing the standard deviation of thickness by the average thickness of the film and multiplying by 100 (%). Here, the standard deviation of thickness refers to the standard deviation of thickness values ​​measured at multiple points in the width direction of the film, and may satisfy Equation 1 below.

[0027] [Equation 1]

[0028]

[0029] In the above Equation 1, is the individual thickness data value, μ is the average thickness, and N represents the total number of data.

[0030] In addition, the above average thickness is the sum of thickness values ​​measured at multiple points along the width direction of the film divided by the number of measurements.

[0031] Furthermore, the above-mentioned relative standard deviation of thickness is an indicator representing the uniformity of the thickness distribution throughout the film, and is a statistical indicator distinct from the above-mentioned relative deviation of thickness (R-difference), which is based on the difference between the maximum and minimum values.

[0032] In addition, the breakdown voltage (BDV) of the polyimide film may be 225 KV / mm or higher, and preferably 226 KV / mm or higher, 227 KV / mm or higher, 228 KV / mm or higher, 229 KV / mm or higher, 230 KV / mm or higher, 231 KV / mm or higher, or 232 KV / mm or higher, and the upper limit thereof may be 500 kV / mm or lower, 400 kV / mm or lower, 350 kV / mm or lower, 330 kV / mm or lower, or 320 kV / mm or lower, although the upper limit is not specifically limited.

[0033] The above breakdown voltage (BDV) can be measured according to methods known in the industry. As an example, the above breakdown voltage can be measured according to the ASTM D149 standard. Specifically, a polyimide film specimen can be pretreated in an oven at 100°C to remove moisture, then fixed to a measuring device (PHENIX TECHNOLOGIES 6CCE50-5) set to a room temperature atmosphere, and a voltage of 10 kVAc is applied between the upper and lower electrodes to increase the AC voltage from 0 at a constant rate to calculate the BDV.

[0034] In addition, the above polyimide film may satisfy Equation 2 below:

[0035] [Equation 2]

[0036] |L MD - L TD | < 0.02 mN / cm

[0037] In the above Equation 2,

[0038] L MDis the loop stiffness value of the film in the machine transport direction, and

[0039] L TD is the loop stiffness value in the width direction of the film.

[0040] Equation 2 above is the loop stiffness value (L) of the film in the machine transport direction. MD ) and the film's width-direction loop stiffness value (L TD This relates to the absolute value of the difference, and the above loop stiffness value is measured by using a loop stiffness tester to fold the film into a loop and compressing it in the diameter direction of the loop, under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm.

[0041] Specifically, the polyimide film of the present invention has a loop stiffness value (L) in the machine transport direction of the film. MD ) and the film's width-direction loop stiffness value (L TD The absolute value of the difference of ) may be less than 0.02 mN / cm, and preferably 0.018 mN / cm or less, 0.017 mN / cm or less, 0.016 mN / cm or less, 0.015 mN / cm or less, 0.014 mN / cm or less, 0.013 mN / cm or less, or 0.012 mN / cm or less. If the absolute value of the difference between the machine transport direction (MD) and the width direction (TD) of the loop stiffness value falls outside the above range, it is undesirable because the desired excellent dimensional stability cannot be achieved.

[0042] More specifically, the polyimide film of the present invention has a machine conveying direction loop stiffness value (L MD ) and the film's width-direction loop stiffness value (L TD The absolute value of the difference is less than 0.02 mN / cm, so the asymmetric deformation of the film in the machine transport direction (MD) and the film width direction (TD) caused by external force is reduced, allowing for excellent dimensional stability.

[0043] Film machine transport direction loop stiffness value (L MD) and the film's width-direction loop stiffness value (L TD In order to keep the absolute value of the difference within a specific range, as described below, it is important to control the content of the imidization solution (including catalyst and dehydrating agent) relative to the polyamic acid solution during film manufacturing, control the catalyst content, and control the dehydrating agent content.

[0044] The thickness of the polyimide film of the present invention is 1 to 10 μm, and preferably, the upper limit may be 9 μm or less, 8.5 μm or less, 8 μm or less, 7.5 μm or less, 7 μm or less, 6 μm or less, or 5.5 μm or less, and the lower limit may be 1.5 μm or more, 2 μm or more, 2.5 μm or more, or 3 μm or more. If the film thickness exceeds 10 μm, the desired ultra-thin polyimide film cannot be realized, and the flexibility of the film is reduced, resulting in lower dimensional stability, which is undesirable.

[0045] The polyimide film of the present invention may have a thickness deviation of 1.15 μm or less as measured using a film tester, preferably 1.13 μm or less, 1.11 μm or less, 1.10 μm or less, 1.08 μm or less, 1.07 μm or less, 1.05 μm or less, or 1.0 μm or less, and the lower limit may be 0.5 μm or more, although not specifically limited. Here, the thickness deviation of the film refers to the difference in thickness between the thinnest part (minimum thickness value) and the thickest part (maximum thickness value) of the film in the width direction, and by controlling the thickness deviation of the film within the above range, excellent dimensional stability can be achieved and the dielectric breakdown voltage can be improved.

[0046] Specifically, the present invention aims to improve the breakdown voltage (BDV) by improving thickness precision and uniformity, and such breakdown voltage (BDV) is more significantly affected by thickness variation within the film than by the thickness of the film itself. In particular, when the thickness variation exceeds 1.15 μm, the breakdown voltage (BDV) may be significantly reduced, and in the case of thin films, since the relative thickness variation increases even with the same thickness variation, the reduction in breakdown voltage (BDV) may be more pronounced compared to films with a thickness exceeding 10 μm.

[0047] In addition, ultra-thin polyimide films have a problem in that appearance defects occur when there is a large variation in thickness. In contrast, according to the present invention, by minimizing the thickness variation of the film and improving thickness precision, appearance defects such as Gauge Band (Lump), Tire Track, color difference, hardness defects, protrusions, and Dents (film deformation caused by protrusions) do not occur or are significantly suppressed, thereby improving the appearance quality of the film.

[0048] The above Gauge Band (Lump) refers to a localized bending or band-shaped thickness non-uniformity phenomenon formed in a roll-shaped film where the relatively thicker parts rise up and the thinner parts sink down relatively.

[0049] In addition, Tire Track refers to a wave-shaped surface irregularity phenomenon that appears repeatedly along the machine direction (MD direction) of the film in a form similar to tire marks.

[0050] In addition, color difference refers to the phenomenon where color differences become prominent within the wound rolls due to thickness variations, resulting from the characteristic of polyimide films being observed in different shades depending on their thickness.

[0051] Furthermore, hardness defects refer to a phenomenon where the winding strength of a roll-type product varies by region due to variations in film thickness; thicker areas are wound relatively strongly, resulting in higher hardness, while thinner areas are wound relatively weakly, resulting in lower hardness. Consequently, if the difference in hardness between locations becomes significant, subsidence or deformation of the roll surface may occur.

[0052] Additionally, a protrusion refers to a phenomenon where a location of relatively thick film protrudes locally due to relatively strong pressure during the winding process, and a dent refers to a mark or film deformation formed as the protrusion is transferred to an adjacent film side.

[0053] In the present invention, “winding” refers to a process of winding a manufactured film into a roll shape under a certain tension for storage or transport.

[0054] In order to set the relative thickness deviation (R-difference), relative standard thickness deviation, and thickness deviation values ​​of the film to specific values, it is important to control the content of the imidization solution (including catalyst and dehydrating agent) relative to the polyamic acid solution, the catalyst content, and the dehydrating agent content during film manufacturing, as described below.

[0055] In addition, the polyimide film of the present invention may satisfy Equation 3 below.

[0056] [Equation 3]

[0057] |ITS MD - ITS TD | ≤ 0.1 kgf

[0058] In the above Equation 3,

[0059] ITS MD is the initiation tear strength value of the film in the machine transport direction, and

[0060] ITS TD is the initial tear strength value in the width direction of the film.

[0061] The above initiation tear strength was measured in accordance with IPC-TM-650-2.4.16B.

[0062] Equation 3 above is the initial tear strength value (ITS) of the film in the machine transport direction. MD ) and the initial tear strength value in the width direction of the film (ITS TD It is about the absolute value of the difference.

[0063] Specifically, the polyimide film of the present invention has an initial tear strength value (ITS) in the machine transport direction of the film. MD ) and the initial tear strength value in the width direction of the film (ITS TD The absolute value of the difference may be 0.1 kgf or less, and preferably 0.090 kgf or less, 0.085 kgf or less, 0.083 kgf or less, 0.082 kgf or less, 0.081 kgf or less, or 0.080 kgf or less. By controlling the absolute value of the difference between the initial tear strength values ​​in the machine transport direction (MD) and the width direction (TD) to within the above range, the winding performance of the ultra-thin film can be good.

[0064] In addition, the polyimide film of the present invention may satisfy Equation 4 below.

[0065] [Equation 4]

[0066] |PTS MD - PTS TD | ≤ 0.15 gf

[0067] In the above Equation 4,

[0068] PTS MD is the propagation tear strength value of the film in the machine transport direction, and

[0069] PTS TD is the tear strength value in the width direction of the film.

[0070] The above propagation tear strength was measured in accordance with IPC-TM-650-2.4.17.

[0071] Equation 4 above is the tear strength value (PTS) propagating in the machine transport direction of the film. MD ) and the film's widthwise tear strength value (PTS TD It is about the absolute value of the difference.

[0072] Specifically, the polyimide film of the present invention has a tear strength value (PTS) in the mechanical transport direction of the film. MD ) and the film's widthwise tear strength value (PTS TD The absolute value of the difference may be 0.15 gf or less, and preferably 0.12 gf or less, 0.11 gf or less, 0.10 gf or less, 0.09 gf or less, or 0.08 gf or less. By controlling the absolute value of the difference between the machine transport direction (MD) and the width direction (TD) of the propagation tear strength value to be within the above range, the windability of the ultrathin film can be good.

[0073] Here, initiation tear strength refers to the force required when tearing begins in the sample, and propagation tear strength represents the average force required to propagate the tear in the sample.

[0074] Generally, as the variation in tear strength along the film direction increases, the film's breakability increases in specific areas, making normal film winding difficult. In fact, as films become ultra-thin, the film's breakability increases significantly, making wide-width and long-width winding difficult. The polyimide film of the present invention has an absolute value of the difference in initial tear strength between the machine conveying direction and the width direction of 0.1 kgf or less, and an absolute value of the difference in propagating tear strength of 0.15 gf or less, so it has the effect of facilitating wide-width (500 to 2,000 mm) and long-width (500 m or more) winding of the film while having a thin thickness of 1 to 10 μm.

[0075] In order to set the absolute value of the difference in tear strength according to the film direction to a specific value, as described below, it is important to control the content of the imidization solution (including catalyst and dehydrating agent) relative to the polyamic acid solution during film manufacturing, as well as to control the catalyst content and dehydrating agent content.

[0076] The tensile strength of the above polyimide film may be 300 MPa or more. For example, the lower limit of the tensile strength may be 305 MPa or more, 310 MPa or more, 315 MPa or more, 318 MPa or more, 319 MPa or more, or 320 MPa or more, and the upper limit is not specifically limited but may be 500 MPa or less.

[0077] The elongation of the above polyimide film may be 40% or more. For example, the lower limit of the elongation may be 45% or more, 46% or more, 47% or more, 48% or more, 49% or more, or 50% or more, and the upper limit is not specifically limited but may be 100% or less.

[0078] The above modulus may be 3 GPa or higher. For example, the lower limit of the above modulus may be 3.1 GPa or higher, 3.2 GPa or higher, 3.3 GPa or higher, 3.4 GPa or higher, or 3.5 GPa or higher, and the upper limit is not specifically limited but may be 18 GPa or lower, 17 GPa or lower, 16 GPa or lower, or 15 GPa or lower.

[0079] That is, the polyimide film of the present invention has a tensile strength of 300 MPa or more, an elongation of 40% or more, and an elastic modulus of 3 GPa or more, and as these characteristics correspond to their respective ranges, it has the desired mechanical properties and can be used as a flexible circuit board.

[0080] Here, the tensile strength, elongation, and elastic modulus were measured using an INSTRON Instron 3365SER machine and a 100 mm X 15 mm sample under conditions of a grip distance of 50 mm and a grip speed of 200 mm / min.

[0081] The coefficient of thermal expansion (CTE) of the above polyimide film may be 20 ppm / ℃ or less. For example, the upper limit of the coefficient of thermal expansion may be 19 ppm / ℃ or less or 18 ppm / ℃ or less, and the lower limit is not specifically limited but may be 0 ppm / ℃ or more.

[0082] The coefficient of thermal expansion in the mechanical transport direction (CTE) of the above polyimide film MD ) and coefficient of thermal expansion in the width direction (CTE TD The absolute value of the difference may be 10 ppm / ℃ or less, and preferably 9 ppm / ℃ or less, 8 ppm / ℃ or less, 7 ppm / ℃ or less, or 6 ppm / ℃ or less.

[0083] That is, the polyimide film of the present invention has a coefficient of thermal expansion of 20 ppm / ℃ or less, and a coefficient of thermal expansion in the mechanical transport direction (CTE). MD ) and coefficient of thermal expansion in the width direction (CTE TDThe absolute value of the difference is 10 ppm / ℃ or less, and as these characteristics fall within their respective ranges, they possess the desired thermal characteristics and can be used as flexible circuit boards.

[0084] The above thermal expansion coefficient is the average value of the thermal expansion coefficient in the machine conveying direction (MD) and the thermal expansion coefficient in the width direction (TD), and the above thermal expansion coefficient in the machine conveying direction (MD) and the thermal expansion coefficient in the width direction (TD) were measured using a TA company TMA equipment (Q400) and a 5 mm X 20 mm sample, with a slope of 10 ℃ / min and 0.05 N in the 100 ~ 200 ℃ range, respectively.

[0085] The above dianhydric monomers are pyromellitic dianhydride (PMDA), biphenyl tetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 2,3,3',4'-benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride (ODPA), diphenylsulfone-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, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimelytic monoester acid anhydride), p-biphenylenebis(trimelytic monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalene tetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic It may include one or more selected from the group consisting of dianhydride and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride, and preferably may include pyromellitic dianhydride (PMDA).

[0086] Specifically, the dianhydric monomer may contain 90 mol% or more of pyromellitic dianhydride (PMDA) based on 100 mol% of the total dianhydric monomer, preferably 93 mol% or more, 95 mol% or more, 96 mol% or more, 97 mol% or more, 98 mol% or more, 99 mol% or more, and more preferably 100 mol%.

[0087] The above diamine monomer is 4,4'-diaminodiphenyl ether (4,4'-ODA), 1,4-diaminobenzene (PPD), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2-bisaminophenoxyphenylpropane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-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'-Diaminodiphenylsulfoxide, 3,4'-Diaminodiphenylsulfoxide, 4,4'-Diaminodiphenylsulfoxide, 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-aminophenylsulfide)benzene, 1,3-Bis(4-aminophenylsulfide)benzene, 1,4-Bis(4-aminophenylsulfide)benzene, 1,3-Bis(3-aminophenylsulfone)benzene, 1,3-Bis(4-aminophenylsulfone)benzene, 1,4-Bis(4-aminophenylsulfone)benzene, 1,3-Bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-Bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-Bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-Bis(3-aminophenoxy)biphenyl, 3,3'-Bis(4-aminophenoxy)biphenyl, 4,4'-Bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, Bis[3-(3-aminophenoxy)phenyl]ether, Bis[3-(4-aminophenoxy)phenyl]ether, Bis[4-(3-aminophenoxy)phenyl]ether, Bis[4-(4-aminophenoxy)phenyl]ether, Bis[3-(3-aminophenoxy)phenyl]ketone, Bis[3-(4-aminophenoxy)phenyl]ketone, Bis[4-(3-aminophenoxy)phenyl]ketone, Bis[4-(4-aminophenoxy)phenyl]ketone, Bis[3-(3-aminophenoxy)phenyl]sulfide, Bis[3-(4-aminophenoxy)phenyl]sulfide, Bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[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,It may include one or more selected from the group consisting 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. Preferably, the diamine monomer may include one or more selected from the group consisting of 4,4'-diaminodiphenyl ether (4,4'-ODA) and 1,4-diaminobenzene (PPD), and more preferably, it may include 4,4'-diaminodiphenyl ether (4,4'-ODA) and 1,4-diaminobenzene (PPD).

[0088] Specifically, the diamine monomer may contain 50 mol% or more of the 4,4'-diaminodiphenyl ether (4,4'-ODA) based on 100 mol% of the total diamine monomer, preferably with a lower limit of 55 mol% or more, 60 mol% or more, 65 mol% or more, 70 mol% or more, or 75 mol% or more, and the upper limit is not particularly limited but may be 95 mol% or less. In addition, the 1,4-diaminobenzene (PPD) may contain 5 mol% or more based on 100 mol% of the total diamine monomer, preferably with 10 mol% or more, 15 mol% or more, 20 mol% or more, 23 mol% or more, 24 mol% or more, and more preferably 25 mol% or more, and the upper limit is not particularly limited but may be 50 mol% or less.

[0089] In one embodiment of the present invention, the polyamic acid may include pyromellitic dianhydride (PMDA), 4,4'-diaminodiphenyl ether (4,4'-ODA), and 1,4-diaminobenzene (PPD) as polymerization units.

[0090] Specifically, the polyamic acid may comprise 100 mol% of pyromellitic dianhydride (PMDA), 50 mol% or more of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 50 mol% or less of 1,4-diaminobenzene (PPD) as polymerization units. Preferably, the polyamic acid may comprise 100 mol% of pyromellitic dianhydride (PMDA), 65 to 85 mol% of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 15 to 35 mol% of 1,4-diaminobenzene (PPD) as polymerization units. More preferably, the polyamic acid may comprise 100 mol% of pyromellitic dianhydride (PMDA), 65 mol% to 85 mol% of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 15 mol% to 35 mol% of 1,4-diaminobenzene (PPD) as polymerization units.

[0091] The above polyimide film may include a cured product of a composition for manufacturing a polyimide film.

[0092] According to another aspect of the present invention, the present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, wherein the relative standard deviation of thickness is 6% or less and the thickness is 1 to 10 μm or less. Here, the relative standard deviation of thickness refers to a value calculated by dividing the standard deviation of thickness by the average thickness of the film and then multiplying by 100 (%). Here, the standard deviation of thickness refers to the standard deviation of thickness values ​​measured at multiple points in the width direction of the film and may satisfy Equation 1 below.

[0093] [Equation 1]

[0094]

[0095] In the above Equation 1, is an individual data value, μ is the mean, and N represents the total number of data.

[0096] In addition, the average thickness is the sum of thickness values ​​measured at multiple points along the width direction of the film divided by the number of measurements.

[0097] The polyimide film of the present invention may satisfy at least one selected from Formulas 1 to 4 mentioned above.

[0098] According to another aspect of the present invention, the present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, wherein the thickness variation of the film measured using a film tester is 1.15 μm or less.

[0099] According to another aspect of the present invention, the present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, satisfying Formula 2 below.

[0100] [Equation 2]

[0101] |L MD - L TD | < 0.02 mN / cm

[0102] In the above Equation 2,

[0103] L MD is the loop stiffness value of the film in the machine transport direction, and

[0104] L TD is the loop stiffness value in the width direction of the film.

[0105] Here, the loop stiffness value is measured by using a loop stiffness tester to fold the film into a loop and compressing it in the diameter direction of the loop, under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm.

[0106] According to another aspect of the present invention, the present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, satisfying Formula 3 below.

[0107] [Equation 3]

[0108] |ITS MD - ITS TD | ≤ 0.1 kgf

[0109] In the above Equation 3,

[0110] ITS MD is the initiation tear strength value of the film in the machine transport direction, and

[0111] ITS TD is the initial tear strength value in the width direction of the film, and

[0112] The above initiation tear strength was measured in accordance with IPC-TM-650-2.4.16B.

[0113] According to another aspect of the present invention, the present invention provides a polyimide film comprising a polyimide having a dianhydride monomer and a diamine monomer as polymerization units, satisfying Formula 4 below.

[0114] [Equation 4]

[0115] |PTS MD - PTS TD | ≤ 0.15 gf

[0116] In the above Equation 4,

[0117] PTS MD is the propagation tear strength value of the film in the machine transport direction, and

[0118] PTS TD is the tear strength value propagated in the width direction of the film, and

[0119] The above propagation tear strength was measured in accordance with IPC-TM-650-2.4.17.

[0120] Composition for manufacturing polyimide film

[0121] The present invention provides a composition for manufacturing a polyimide film comprising: a polyamic acid solution containing a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises 60 parts by weight or more of the imidization solution based on 100 parts by weight of the polyamic acid solution, the relative thickness deviation (R-difference) of the polyimide film is 25% or less, and the thickness of the polyimide film is 1 to 10 μm. Here, the relative thickness deviation (R-difference) is a value calculated by dividing the thickness deviation by the average thickness of the film and multiplying by 100 (%), and the thickness deviation refers to the difference between the maximum thickness value and the minimum thickness value among the thicknesses measured using a film tester along the width direction of the film.

[0122] Specifically, the upper limit of the above thickness relative deviation (R difference) may be 25% or less, 24.95% or less, 24.90% or less, 24.85% or less, or 24.80% or less, and the lower limit may be 1% or more, 5% or more, or 10% or more, but is not limited thereto. Here, if the above thickness relative deviation (R difference) exceeds 25%, the dielectric breakdown voltage (BDV) may decrease, which is undesirable.

[0123] In addition, the polyimide film may satisfy at least one selected from Formulas 1 to 4 mentioned above.

[0124] Specifically, the composition may contain at least 60 parts by weight, preferably at least 70 parts by weight, at least 75 parts by weight, at least 77 parts by weight, and more preferably at least 78 parts by weight, of the imidization solution based on 100 parts by weight of the polyamic acid solution. By limiting the content of the imidization solution to the above range, the composition for manufacturing a polyimide film according to the present invention can produce a polyimide film having an ultrathin thickness (1 to 10 μm) while having high thickness uniformity and dimensional stability.

[0125] The above imidization solution may contain 80 to 200 mol% of a catalyst based on 100 mol% of the polyamic acid, preferably with a lower limit of 82 mol%, 85 mol%, 90 mol%, 100 mol%, 110 mol%, or 120 mol% or more, and an upper limit of 190 mol%, 180 mol%, 170 mol%, 160 mol%, 155 mol%, or 152 mol% or less. By including the catalyst within the above range, a polyimide film with a desired thin thickness (1 to 10 μm) and high thickness uniformity and dimensional stability can be manufactured.

[0126] The catalyst may include one or more selected from the group consisting of pyridine, isoquinoline, beta-picoline, trimethylamine, triethylenediamine, and dimethylaniline, preferably one or more selected from the group consisting of pyridine, isoquinoline, beta-picoline, and trimethylamine, and more preferably isoquinoline.

[0127] The above imidization solution may contain 650 to 1,200 mol% of a dehydrating agent based on 100 mol% of the polyamic acid, preferably the lower limit may be 660 mol%, 670 mol%, 680 mol%, 690 mol%, 700 mol%, 750 mol%, 800 mol%, or 850 mol% or more, and the upper limit may be 1,100 mol%, 1,000 mol%, 950 mol%, 930 mol%, or 900 mol% or less. By including the dehydrating agent within the above range, a polyimide film having a desired thin thickness (1 to 10 μm) and high thickness uniformity and dimensional stability can be manufactured.

[0128] The above dehydrating agent may include one or more selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, and benzoic anhydride, and preferably may include acetic anhydride.

[0129] The polyamic acid solution and the imidization solution of the above composition may each additionally include a solvent, and each solvent may be the same or different from one another.

[0130] The above solvent may include one or more selected from the group consisting of N,N'-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N'-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), diethylacetamide (DEAc), N-ethyl-2-pyrrolidone (NEP), N,N'-diethylformamide (DEF), dimethylpropanamide (DMPA), and gamma-butyrolactone (GBL), and preferably N,N'-dimethylformamide (DMF) may be used.

[0131] In one embodiment of the present invention, the composition for manufacturing the polyimide film may comprise a polyamic acid solution comprising a polyamic acid comprising pyromellitic dianhydride (PMDA), 4,4'-diaminodiphenyl ether (4,4'-ODA), and 1,4-diaminobenzene (PPD) as polymerization units, and a solvent; and an imidation solution; wherein the solvent may comprise N,N'-dimethylformamide (DMF), and the imidation solution may comprise isoquinoline (IQ) and acetic anhydride (AA).

[0132] Specifically, the polyamic acid solution may comprise a polyamic acid and N,N'-dimethylformamide (DMF) comprising 100 mol% of pyromellitic dianhydride (PMDA), 50 mol% or more of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 50 mol% or less of 1,4-diaminobenzene (PPD) as polymerization units, and the composition for manufacturing the polyimide film may comprise 60 to 90 parts by weight of an imidization solution per 100 parts by weight of the polyamic acid solution, and the imidization solution may comprise 80 to 170 mol% of isoquinoline and 700 to 1100 mol% of acetic anhydride based on 100 mol% of the polyamic acid.

[0133] Preferably, the polyamic acid solution may comprise a polyamic acid and N,N'-dimethylformamide (DMF) comprising 100 mol% of pyromellitic dianhydride (PMDA), 60 to 90 mol% of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 10 to 40 mol% of 1,4-diaminobenzene (PPD) as polymerization units, and the composition for manufacturing the polyimide film may comprise 60 to 85 parts by weight of an imidization solution per 100 parts by weight of the polyamic acid solution, and the imidization solution may comprise 80 to 160 mol% of isoquinoline and 700 to 1000 mol% of acetic anhydride based on 100 mol% of the polyamic acid.

[0134] According to another aspect of the present invention, the present invention provides a composition for manufacturing a polyimide film comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises 60 parts by weight or more of the imidization solution based on 100 parts by weight of the polyamic acid solution, the relative standard deviation of the thickness of the polyimide film is 6% or less, and the thickness of the polyimide film is 1 to 10 μm.

[0135] Here, the above-mentioned thickness relative standard deviation refers to a value calculated by dividing the thickness standard deviation by the average thickness of the film and multiplying by 100 (%). In addition, the thickness standard deviation refers to the standard deviation of thickness values ​​measured at multiple points in the width direction of the film and may satisfy Equation 1 below.

[0136] [Equation 1]

[0137]

[0138] In the above Equation 1, is an individual data value, μ is the mean, and N represents the total number of data.

[0139] In addition, the average thickness is a value obtained by dividing the sum of thickness values ​​measured at multiple points along the width direction of the film by the number of measurements, and the composition for manufacturing a polyimide film has a thickness of 1 to 10 μm.

[0140] In addition, the polyimide film may satisfy at least one selected from the thickness relative deviation (R difference) and the above-mentioned Equations 2 to 4.

[0141] According to another aspect of the present invention, the present invention provides a composition for manufacturing a polyimide film, comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises 60 parts by weight or more of the imidization solution based on 100 parts by weight of the polyamic acid solution, and the polyimide film has a thickness variation of 1.15 μm or less as measured using a film tester.

[0142] In addition, the polyimide film may satisfy at least one selected from the thickness relative deviation (R difference) and the above-mentioned formulas 1 to 4.

[0143] According to another aspect of the present invention, the present invention provides a composition for manufacturing a polyimide film, comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises 60 parts by weight or more of the imidization solution based on 100 parts by weight of the polyamic acid solution, and the polyimide film satisfies Formula 2 below.

[0144] [Equation 2]

[0145] |L MD - L TD | < 0.02 mN / cm

[0146] In the above Equation 2,

[0147] L MD is the loop stiffness value of the film in the machine transport direction, and

[0148] L TD is the loop stiffness value in the width direction of the film, and

[0149] Here, the above-mentioned loop stiffness value is measured by using a loop stiffness tester to fold the film into a loop and compressing it in the diameter direction of the loop, under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm.

[0150] In addition, the polyimide film may satisfy at least one selected from the thickness relative deviation (R difference) and the aforementioned Equations 1, 3 to 4.

[0151] According to another aspect of the present invention, the present invention provides a composition for manufacturing a polyimide film, comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises at least 60 parts by weight of the imidization solution based on 100 parts by weight of the polyamic acid solution, and the polyimide film satisfies Formula 3 below.

[0152] [Equation 3]

[0153] |ITS MD - ITS TD | ≤ 0.1 kgf

[0154] In the above Equation 3,

[0155] ITS MD is the initiation tear strength value of the film in the machine transport direction, and

[0156] ITS TD is the initial tear strength value in the width direction of the film, and

[0157] The above initiation tear strength was measured in accordance with IPC-TM-650-2.4.16B.

[0158] In addition, the polyimide film may satisfy at least one selected from the thickness relative deviation (R-difference) of Equations 1, 2, and 4 mentioned above.

[0159] According to another aspect of the present invention, the present invention provides a composition for manufacturing a polyimide film, comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; wherein the composition comprises 60 parts by weight or more of the imidization solution based on 100 parts by weight of the polyamic acid solution, and the polyimide film satisfies Formula 4 below.

[0160] [Equation 4]

[0161] |PTS MD - PTS TD | ≤ 0.15 gf

[0162] In the above Equation 4,

[0163] PTS MD is the propagation tear strength value of the film in the machine transport direction, and

[0164] PTS TD is the tear strength value propagated in the width direction of the film, and

[0165] The above propagation tear strength was measured in accordance with IPC-TM-650-2.4.17.

[0166] In addition, the polyimide film may satisfy at least one selected from the thickness relative deviation (R difference) and the above-mentioned formulas 1 to 3.

[0167] The present invention provides a polyimide film comprising a cured product of the composition for manufacturing a polyimide film. More specifically, the cured product may be prepared by imidizing the composition for manufacturing a polyimide film and may be in the form of a film.

[0168] Another embodiment of the present invention provides a flexible circuit board comprising the polyimide film.

[0169] Another embodiment of the present invention provides an electronic component comprising the flexible circuit board.

[0170] Another embodiment of the present invention provides a display element comprising the polyimide film.

[0171] The polyimide film of the present invention has a thickness relative deviation (R difference) of 25% or less and a thickness relative standard deviation of 6% or less, and by manufacturing an ultra-thin (1 to 10 μm) polyimide film, it has high dimensional stability and excellent dielectric breakdown voltage (BDV), and by minimizing thickness deviation to improve thickness precision, it has the effect of improving the appearance of the film and improving the deviation of BDV.

[0172] In addition, the polyimide film of the present invention has high dimensional stability with an absolute value of the difference in loop stiffness between the machine transport direction (MD) and the width direction (TD) of less than 0.02 mN / cm, and has the effect of being thin, wide, and easy to wind into a long coil.

[0173] The polyimide film of the present invention has the effect of high dimensional stability with a thickness variation of 1.15 μm or less.

[0174] The polyimide film of the present invention has high dimensional stability with an absolute value of the difference in initiation tear strength between the machine transport direction (MD) and the width direction (TD) of 0.1 kgf or less, and has the effect of being thin, wide, and easy to wind into a long roll.

[0175] The polyimide film of the present invention has high dimensional stability with an absolute value of the difference in propagation tear strength between the machine transport direction (MD) and the width direction (TD) of 0.15 gf or less, and has the effect of being thin, wide, and easy to wind into a long roll.

[0176] In addition, the polyimide film of the present invention has excellent mechanical and thermal properties.

[0177] In addition, the polyimide film according to the present invention has the effect of being applicable to flexible circuit boards.

[0178] Examples are provided to aid in understanding the present invention. The following examples are provided merely to facilitate a better understanding of the invention, and the scope of the invention is not limited by these examples.

[0179] <Example 1: Polyimide Film>

[0180] Example 1

[0181] N,N'-dimethylformamide (DMF) solvent was introduced into a reaction vessel purged with nitrogen gas, and 100 mol% of pyromellitic dianhydride (PMDA), 75 mol% of 4,4'-diaminodiphenyl ether (4,4'-ODA), and 25 mol% of 1,4-diaminobenzene (PPD) were mixed to prepare a polyamic acid solution containing polyamic acid.

[0182] To the above polyamic acid solution, 80 parts by weight of an imidization solution containing a catalyst (isoquinoline) and a dehydrating agent (acetic anhydride) were added for every 100 parts by weight of the above polyamic acid solution, and the polyamic acid solution and the imidization solution were mixed.

[0183] A polyimide film with a thickness of 3.4 μm was prepared by casting the above mixture onto a support through a die and forming a film.

[0184] At this time, the imidization solution is a mixture of 150 mol% isoquinoline and 890 mol% acetic anhydride based on 100 mol% of the polyamic acid in an N,N'-dimethylformamide (DMF) solvent.

[0185] Examples 2 to 7

[0186] A polyimide film was prepared using the same method as in Example 1, except that the content of the imidization solution and the thickness of the polyimide film were changed as described in Table 1.

[0187] Comparative Examples 1 to 6

[0188] A polyimide film was prepared using the same method as in Example 1, except that the content of the imidization solution and the thickness of the polyimide film were changed as described in Table 1.

[0189] Reference Examples 1 to 4

[0190] A polyimide film was prepared using the same method as in Example 1, except that the content of the imidization solution and the thickness of the polyimide film were changed as described in Table 1.

[0191] Table 1 below summarizes the content of each of the dianhydride monomer, diamine monomer, catalyst, and dehydrating agent used when preparing polyimide films according to Examples 1 to 7, Comparative Examples 1 to 6, and Reference Examples 1 to 4, as well as the content of the imidization solution relative to the polyamic acid solution and the thickness of the film.

[0192] Classification Polyamic Acid Solution Imidization Solution Content of Imidization Solution per 100 parts by weight of Polyamic Acid Solution (parts by weight) Thickness (㎛) PMDA (mol%) ODA (mol%) PPD (mol%) IQ (mol%) AA (mol%) Example 1 100 75 25 150 890 80.0 3.4 Example 2 150 890 80.0 4.3 Example 3 150 890 80.0 5.0 Example 4 130 800 80.0 3.0 Example 5 130 800 80.0 4.0 Example 6 130 800 80.0 5.0 Example 7 80 700 60.0 7.5 Comparative Example 190 540 48.0 12.5 Comparative Example 2 70 440 39.0 25 Comparative Example 3 100 600 60 3.0 Comparative Example 4100600604.0 Comparative Example 5100600605 Comparative Example 660500407.5 Reference Example 1706005012.5 Reference Example 2504003012.5 Reference Example 3706005015 Reference Example 4504003015

[0193] The abbreviations in Table 1 above are as follows.

[0194] PMDA: Pyromelittic dianhydride

[0195] ODA: 4,4'-Diaminodiphenyl ether

[0196] PPD: 1,4-diaminobenzene

[0197] IQ: Isoquinoline

[0198] AA: Acetic anhydride

[0199]

[0200] <Experimental Example>

[0201] Experimental Example 1: Loop Stiffness Analysis

[0202] The machine-feed direction loop stiffness and width direction loop stiffness values ​​of the polyimide films of Examples 1 to 3 and Comparative Examples 1 to 2 were measured, respectively, using a loop stiffness tester (TOYOSEIKI). Specifically, loop stiffness is defined as the stress measured when the film is folded into a loop and compressed in the diameter direction of the loop; measurements were taken under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm. The measured machine-feed direction loop stiffness value (L MD ), width-direction loop stiffness value (L TD ) and the difference between the two (|L MD - L TD |) is summarized in Table 2 below.

[0203] Separation Loop Stiffness (mN / cm) Machine Return Direction (L MD )Width direction (L TD )Difference value (|L MD - L TD Example 10.0100.0100.000 Example 20.0280.0200.008 Example 30.0540.0660.012 Comparative Example 11.1121.0900.022 Comparative Example 28.8348.6000.234

[0204]

[0205] According to Table 2 above, Examples 1 to 3, which are polyimide films prepared by using an imidization solution comprising 80 to 200 mol% of a catalyst and 650 to 1,200 mol% of a dehydrating agent per 100 mol% of a polyamic acid solution in an amount of 60 parts by weight or more per 100 parts by weight of a polyamic acid solution, have a machine conveying direction loop stiffness value (L MD ), width-direction loop stiffness value (L TD It can be confirmed that each of them is 0.07 mN / cm or less, and the absolute value of the difference in loop stiffness between the machine conveying direction and the width direction is also less than 0.02 mN / cm.

[0206] If the loop strength exceeds 1.0 mN / cm, the flexibility of the film as a flexible circuit substrate is compromised. Loop strength represents the drag force when bending the film and significantly influences the bendability, followability, and flexibility when forming a flexible circuit. The polyimide film of the present invention has a machine transport direction loop stiffness value (L MD ), width-direction loop stiffness value (L TD It was confirmed that each had excellent flexibility and high dimensional stability, with each having a value of 0.07 mN / cm or less.

[0207] The smaller the difference in loop stiffness between the machine conveying direction and the width direction, the less asymmetric deformation of the film in the machine conveying direction (MD) and the width direction (TD) caused by external forces, resulting in excellent dimensional stability. Accordingly, it was confirmed that the polyimide film of the present invention has excellent dimensional stability, with the absolute value of the difference in loop stiffness between the machine conveying direction and the width direction being less than 0.02 mN / cm.

[0208]

[0209] Experimental Example 2: Thickness Variation Analysis

[0210] The thickness variation of the polyimide films prepared according to Examples 1 to 3 was measured using a film tester (FUJIWORK Film Tester) (Resolution 0.01 μm). Here, the thickness variation of the film refers to the difference in thickness between the thinnest and thickest parts of the film in the width direction, and the results are shown in Table 3 below.

[0211] Classification Thickness (㎛) Thickness Deviation (㎛) Example 13.4 0.6 Example 24.3 0.5 Example 35.00.5

[0212]

[0213] According to Table 3 above, Examples 1 to 3, prepared by using at least 60 parts by weight of an imidization solution containing 80 to 200 mol% of a catalyst and 650 to 1,200 mol% of a dehydrating agent per 100 mol% of a polyamic acid solution, can be confirmed to have a thickness of 1 to 10 μm and a thickness variation of 1.15 μm or less, particularly 0.7 μm or less.

[0214]

[0215] Experimental Example 3: Analysis of Polyimide Film Thickness Uniformity According to Thickness Variation Index

[0216] For the polyimide films according to Examples 4 to 7, Comparative Examples 3 to 6 and Reference Examples 1 to 4, the thickness was measured in the width direction of the film.

[0217] Specifically, when the film width direction length was 200 mm or less, the thickness was measured at 10 to 20 points at 20 mm intervals; when the film width direction length was 200 mm to 500 mm, the thickness was measured at 10 to 20 points at 20 mm to 50 mm intervals; and when the film width direction length exceeded 500 mm, the thickness was measured at 10 to 20 points at 50 mm intervals. These thicknesses were measured using a film tester (FUJIWORK Film Tester). Based on the measured values, the average thickness, standard deviation of thickness, relative standard deviation of thickness, thickness difference, and relative difference of thickness were calculated as follows, and the values ​​are summarized in Table 4.

[0218] [Equation 5] Relative standard deviation of thickness (%) = (Standard deviation of thickness ÷ Average thickness) * 100

[0219] [Equation 6] Relative thickness deviation (R-difference) (%) = (Thickness deviation ÷ Average thickness) * 100

[0220] Here, the average thickness is the sum of the thickness values ​​measured at multiple points along the width direction of the film divided by the number of measurements, and the thickness standard deviation is the standard deviation of the thickness values ​​measured at multiple points along the width direction of the film according to Equation 1 below, and the thickness deviation is the difference in thickness between the thinnest part (minimum value) and the thickest part (maximum value) among the thickness values ​​measured along the width direction of the film.

[0221] [Equation 1]

[0222]

[0223] In the above Equation 1, is the individual thickness data value, μ is the average thickness, and N represents the total number of data.

[0224] Classification Average Thickness (㎛) Thickness Standard Deviation (㎛) Thickness Relative Standard Deviation (%) Thickness Deviation (㎛) Thickness Relative Deviation (R-difference) (%) Example 4 3.3 90.2 05.9 0.8 424.8 Example 5 4.2 80.2 14.9 0.8 720.3 Example 6 5.2 80.2 34.4 0.9 317.6 Example 7 7.5 80.2 43.2 11.0 614.0 Comparative Example 3 3.2 70.2 98.9 1.2 236.0 Comparative Example 4 4.3 40.3 37.6 1.3 732.0 Comparative Example 55.2 50.3 56.7 1.4 727.8 Comparative Example 6 7.4 90.4 86.4 1.9 826.1

[0225]

[0226] According to Table 4 above, the polyimide films of Examples 4 to 7, prepared by using an imidization solution containing 80 to 200 mol% of catalyst and 650 to 1,200 mol% of dehydrating agent per 100 mol% of polyamic acid solution in an amount of 60 parts by weight or more per 100 parts by weight of polyamic acid solution, have a thickness of 1 to 10 μm, and the thickness variation is controlled to be 1.15 μm or less, the thickness relative variation (R difference) to be 25% or less, and the thickness relative standard variation to be 6% or less, confirming that the thickness uniformity is excellent.

[0227] On the other hand, Comparative Examples 3 to 6 were found to have non-uniform thickness, with a thickness deviation exceeding 1.15 μm, a thickness relative deviation (R-difference) exceeding 25%, and a thickness relative standard deviation exceeding 6%.

[0228]

[0229] Experimental Example 4: Evaluation of Appearance and BDV of Polyimide Film

[0230] (1) Appearance evaluation

[0231] The appearance of the polyimide films according to Examples 4 to 7, Comparative Examples 3 to 6, and Reference Examples 1 to 4 was evaluated based on the occurrence of appearance defects such as Gauge Band (Lump), Tire Track, color difference, poor hardness, protrusions, and Dent (film deformation due to protrusions). If no of the aforementioned appearance defects were observed, it was marked with '○' to indicate good appearance, and if one or more of the above appearance defects were observed, it was marked with 'X' to indicate poor appearance, and these results are summarized in Table 5.

[0232] (2) BDV evaluation

[0233] The dielectric breakdown voltage (BDV) values ​​of the polyimide films prepared in Examples 4 to 7 and Comparative Examples 3 to 6 were measured according to the ASTM D149 standard. Specifically, the polyimide films were pretreated in an oven at 100°C to remove moisture, then fixed to a measuring device (PHENIX TECHNOLOGIES 6CCE50-5) set to a room temperature atmosphere, and a voltage of 10 kVAc was applied between the upper and lower electrodes to increase the AC voltage from 0 at a constant rate to measure the BDV. The measurement results are shown in Table 5 below.

[0234] Classification Average Thickness (㎛) Thickness Relative Standard Deviation (%) Thickness Relative Deviation (R-difference) (%) Appearance BDDV (KV / mm) Example 4 3.39 5.92 4.8○233 Example 5 4.28 4.92 0.3○249 Example 6 5.28 4.41 7.6○272 Example 7 7.58 3.21 4.0○295 Comparative Example 3 3.27 8.93 6.0X195 Comparative Example 4 4.34 7.63 2.0X205 Comparative Example 5 5.25 6.72 7.8X213 Comparative Example 6 7.49 6.42 6.1X220 Reference Example 1 12.13 2.11 1.1○319 Reference Example 2 12.24 6.92 6.5○256 Reference Example 314.252.010.2○332 (See Example 414.536.325.7○278)

[0235]

[0236] According to Table 5 above, it can be confirmed that in Examples 4 to 7 of the present invention, the thickness relative deviation (R difference) is controlled to be 25% or less and the thickness relative standard deviation is controlled to be 6% or less, thereby suppressing appearance defects and maintaining an excellent dielectric breakdown voltage (BDV) of 233 to 295 KV / mm.

[0237] On the other hand, Comparative Examples 3 to 6 each had an average thickness similar to Examples 4 to 7, but the thickness relative deviation (R difference) exceeded 25% and the thickness relative standard deviation exceeded 6%, which fell outside the scope of the present invention, resulting in appearance defects and a tendency for the BDV to decrease to 220 KV / mm or less.

[0238] Meanwhile, it can be confirmed that Reference Examples 1 to 4 have excellent appearance and dielectric breakdown voltage even though the thickness relative deviation (R difference) exceeds 25% or the thickness relative standard deviation exceeds 6%.

[0239] From this, it can be seen that dielectric breakdown voltage (BDV) and appearance quality are more significantly influenced by thickness deviation indicators, such as the relative thickness deviation (R-difference) and the relative standard thickness deviation, rather than the average thickness of the film itself.

[0240] In particular, for ultra-thin films with a thickness of 10 μm or less, electrical reliability and appearance quality tend to be largely influenced by minute thickness variations rather than the average thickness of the film itself, and it is not easy to process precisely control such thickness variations. Nevertheless, according to the present invention, by precisely controlling the relative thickness variation (R-difference) and the relative standard thickness variation within the range of the present invention, the occurrence of appearance defects is suppressed even in ultra-thin films, and the effect of ensuring excellent dielectric breakdown voltage (BDV) can be achieved.

[0241] (3) Multiple regression analysis of dielectric breakdown voltage according to film thickness and relative thickness deviation

[0242] Based on the experimental results in Table 5 above, multiple regression analysis was performed on multivariate parameters according to Equation 7 below to quantify the correlation between the average thickness of the film and the relative thickness deviation (R difference) (%) on the dielectric breakdown voltage.

[0243] [Equation 7]

[0244] BVD=A*DB*R+C

[0245] In the above Equation 7, A represents the thickness constant, D represents the average thickness, B represents the R-order constant, R represents the R-order, and C represents the material constant.

[0246] The results of deriving regression models for each experimental group while fixing the material constant 269 derived based on the trend lines of Examples 4 to 7 are shown in Table 6 below.

[0247] Classification Regression Formula Thickness Sensitivity (A) Deviation Sensitivity (B) Insulation Sensitivity Ratio (B / A) * 100 Coefficient of Determination (R²) Examples 4 to 7 BDV = 14.1 D - 3.4 R + 269 14.1 3.4 approx. 24% 0.984 Comparative Examples 3 to 6 BDV = 0.83 D - 2.13 R + 269 0.8 32.13 approx. 256% 0.995 Reference Examples 1 to 4 BDV = 7.36 D - 3.85 R + 269 7.3 63.85 approx. 52% 0.989

[0248]

[0249] According to Table 6 above, Examples 4 to 7 of the present invention exhibited linear behavior in which the BDV was predominantly influenced by changes in thickness as the thickness deviation was stably controlled. On the other hand, in Comparative Examples 3 to 6, where deviation control was insufficient in the ultrathin film region, a reversal phenomenon was observed in which the insulation sensitivity ratio rapidly increased to approximately 256%.

[0250] This suggests that in the ultrathin film region, process means for finely controlling the R-difference have a decisive influence on securing BDV, rather than design means for increasing physical thickness. Furthermore, regarding the trend lines of Reference Examples 1 to 4, rather than the thickness of the ultrathin film region, it suggests that the influence of thickness on BDV is greater than that of controlling the R-difference, regardless of whether the R-difference is controlled or not. It can be confirmed that this phenomenon of influence reversal is a critical behavior unique to ultrathin films.

[0251]

[0252] Experimental Example 5: Tear strength analysis

[0253] The initiation tear strength values ​​in the mechanical conveying direction and the initiation tear strength values ​​in the width direction of the polyimide films prepared according to Examples 1 to 3 were each measured according to IPC-TM-650-2.4.16B, and the propagation tear strength values ​​in the mechanical conveying direction and the propagation tear strength values ​​in the width direction of the polyimide films prepared according to Examples 1 to 3 were each measured according to IPC-TM-650-2.4.17.

[0254] Here, initiation tear strength refers to the force required when tearing begins in the sample, and propagation tear strength represents the average force required to propagate the tear in the sample.

[0255] Measured initial tear strength in the machine return direction (ITS) MD ), initial tear strength in the width direction (ITS TD ) and the difference between the two (|ITS MD - ITS TD |) and machine return direction propagation tear strength (PTS MD ), widthwise propagated tear strength (PTS TD ) and the difference between the two (|PTS MD - PTS TD |) is summarized in Table 7 below.

[0256] Classification Initial tear strength (kgf) Full tear strength (gf) Machine conveying direction (ITS) MD )Width direction (ITS TD )Difference value (|ITS MD - ITS TD |) Machine return direction (PTS) MD )Width direction (PTS TD )Difference value (|PTS MD - PTS TD |)Example 10.180.180.000.290.300.01Example 20.360.280.080.400.470.07Example 30.380.360.020.690.640.05

[0257]

[0258] According to Table 7 above, Examples 1 to 3, which are polyimide films prepared by using an imidization solution containing 80 to 200 mol% of catalyst and 650 to 1,200 mol% of dehydrating agent per 100 mol% of polyamic acid solution in an amount of 60 parts by weight or more per 100 parts by weight of polyamic acid solution, can be confirmed to have an absolute value of the difference in initial tear strength between the mechanical conveying direction and the width direction of 0.1 kgf or less, and an absolute value of the difference in propagated tear strength between the mechanical conveying direction and the width direction of 0.15 gf or less.

[0259] Generally, as the variation in tear strength along the film direction increases, the film's breakability increases in specific areas, making normal film winding difficult. In fact, as films become ultra-thin, the film's breakability increases significantly, making wide-width and long-width winding difficult. The polyimide film of the present invention has an absolute value of the difference in initial tear strength between the machine conveying direction and the width direction of 0.1 kgf or less, and an absolute value of the difference in propagating tear strength of 0.15 gf or less, so it has the effect of facilitating wide-width (500 to 2,000 mm) and long-width (500 m or more) winding of the film while having a thin thickness of 1 to 10 μm.

[0260]

[0261] Experimental Example 6: Analysis of Mechanical Properties

[0262] The tensile strength, elongation, and modulus of the polyimide films prepared according to Examples 1 to 3 in the machine transport direction (MD) and width direction (TD) were measured and summarized in Table 8 below. The tensile strength, elongation, and modulus were measured using an INSTRON Instron 3365SER machine and a 100 mm X 15 mm sample under conditions of a grip gap of 50 mm and a grip speed of 200 mm / min.

[0263] Classification Tensile Strength (MPa) Elongation (%) Modulus (GPa) MDTDMDTDMDTD Example 1 3 2 4 3 2 9 5 6 5 4 4.1 4.1 Example 2 3 3 0 3 4 0 5 7 5 5 3.9 3.9 Example 3 3 3 0 3 3 9 5 8 5 2 3.7 3.8

[0264]

[0265] According to Table 8 above, the polyimide film of the present invention has a tensile strength of 300 MPa or more, an elongation of 40% or more, and an elastic modulus of 3 GPa or more, confirming that it has excellent mechanical properties.

[0266]

[0267] Experimental Example 7: Analysis of Thermal Properties

[0268] Coefficient of thermal expansion in the mechanical transport direction (CTE) of polyimide films prepared according to Examples 1 to 3 MD ), coefficient of thermal expansion in the width direction (CTE TD ) and the difference between the two (|CTE MD - CTE TD The coefficients of thermal expansion in the machine conveying direction (MD) and the coefficients of thermal expansion in the width direction (TD) were measured using a TA TMA machine (Q400) and a 5 mm X 20 mm sample, respectively, at 10 ℃ / min and 0.05 N, with slopes in the 100 ~ 200 ℃ range.

[0269] Coefficient of thermal expansion (ppm / ℃) MDTD (|MD - TD|) Example 1 12186 Example 2 13185 Example 3 12164

[0270]

[0271] According to Table 9 above, the average value of the coefficient of thermal expansion in the machine transport direction (MD) and the coefficient of thermal expansion in the width direction (TD) of the polyimide film of the present invention is 20 ppm / ℃ or less, and the coefficient of thermal expansion in the machine transport direction (CTE) MD ) and coefficient of thermal expansion in the width direction (CTE TD It was confirmed that the thermal properties were excellent, with the absolute value of the difference being 10 ppm / ℃ or less.

[0272]

[0273] The features of the embodiments and aspects described above may be combined unless combining them results in an obvious technical conflict.

[0274] The specification omits detailed descriptions of matters that can be sufficiently recognized and inferred by those skilled in the art of the present invention, and various modifications are possible within the scope of not altering the technical concept or essential configurations of the present invention, in addition to the specific examples described in this specification. Accordingly, the present invention may be implemented in a manner different from that specifically described and exemplified in this specification, and this is a matter that can be understood by those skilled in the art.

Claims

1. A polyimide having a dianhydride monomer and a diamine monomer as polymerization units, comprising The relative thickness deviation (R-difference) is 25% or less, and The above thickness relative deviation (R-difference) is a value calculated by dividing the thickness deviation by the average thickness of the film and multiplying by 100 (%), and the above thickness deviation is the difference between the maximum thickness value and the minimum thickness value among the thicknesses measured using a film tester along the width direction of the film. Polyimide film having a thickness of 1 to 10 μm or less.

2. In Paragraph 1, The relative standard deviation of the thickness of the above polyimide film is 6% or less, and The above-mentioned relative standard deviation of thickness is a value calculated by dividing the standard deviation of thickness by the average thickness of the film and multiplying by 100 (%), wherein the standard deviation of thickness is the standard deviation of thickness values ​​measured at multiple points in the width direction of the film according to Equation 1 below, and the average thickness is a value obtained by dividing the sum of thickness values ​​measured at multiple points along the width direction of the film by the number of measurements, for a polyimide film: [Equation 1] In the above Equation 1, is an individual thickness data value, and μ is the average thickness, and N is the total number of data.

3. In Paragraph 1, A polyimide film having a breakdown voltage (BDV) of 225 KV / mm or higher.

4. In Paragraph 1, The above polyimide film is a polyimide film satisfying the following Equation 2: [Equation 2] |L MD - L TD | < 0.02 mN / cm In the above Equation 2, L MD is the loop stiffness value of the film in the machine transport direction, and L TD is the loop stiffness value in the width direction of the film, and The above loop stiffness value was measured by using a loop stiffness tester to fold the film into a loop and compressing it in the diameter direction of the loop, under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm.

5. In Paragraph 1, The above polyimide film is a polyimide film having a thickness variation of 1.15 μm or less as measured using a film tester.

6. In Paragraph 1, The above polyimide film is a polyimide film satisfying Equation 3 below: [Equation 3] |ITS MD - ITS TD | ≤ 0.1 kgf In the above Equation 3, ITS MD is the initiation tear strength value of the film in the machine transport direction, and ITS TD is the initial tear strength value in the width direction of the film, and The above initiation tear strength was measured in accordance with IPC-TM-650-2.4.16B.

7. In Paragraph 1, The above polyimide film is a polyimide film satisfying the following Equation 4: [Equation 4] |PTS MD - PTS TD | ≤ 0.15 gf In the above Equation 4, PTS MD is the propagation tear strength value of the film in the machine transport direction, and PTS TD is the tear strength value propagated in the width direction of the film, and The above propagation tear strength was measured in accordance with IPC-TM-650-2.4.

17.

8. In Paragraph 1, The above dianhydric monomers are pyromellitic dianhydride (PMDA), biphenyl tetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 2,3,3',4'-benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride (ODPA), diphenylsulfone-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, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, p-phenylenebis(trimelytic monoester acid anhydride), p-biphenylenebis(trimelytic monoester acid anhydride), m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalene tetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic A polyimide film comprising one or more selected from the group consisting of dianhydride and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid dianhydride.

9. In Paragraph 1, A polyimide film in which the above dianhydric monomer contains 90 mol% or more of pyromellitic dianhydride (PMDA) based on 100 mol% of the total above dianhydric monomer.

10. In Paragraph 1, The above diamine monomer is 4,4'-diaminodiphenyl ether (4,4'-ODA), 1,4-diaminobenzene (PPD), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-tolidine), 2,2-bisaminophenoxyphenylpropane (BAPP), metaphenylenediamine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminobenzoic acid (DABA), 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminobenzanilide, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-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'-Diaminodiphenylsulfoxide, 3,4'-Diaminodiphenylsulfoxide, 4,4'-Diaminodiphenylsulfoxide, 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-aminophenylsulfide)benzene, 1,3-Bis(4-aminophenylsulfide)benzene, 1,4-Bis(4-aminophenylsulfide)benzene, 1,3-Bis(3-aminophenylsulfone)benzene, 1,3-Bis(4-aminophenylsulfone)benzene, 1,4-Bis(4-aminophenylsulfone)benzene, 1,3-Bis[2-(4-aminophenyl)isopropyl]benzene, 1,4-Bis[2-(3-aminophenyl)isopropyl]benzene, 1,4-Bis[2-(4-aminophenyl)isopropyl]benzene, 3,3'-Bis(3-aminophenoxy)biphenyl, 3,3'-Bis(4-aminophenoxy)biphenyl, 4,4'-Bis(3-aminophenoxy)biphenyl, 4,4'-Bis(4-aminophenoxy)biphenyl, Bis[3-(3-aminophenoxy)phenyl]ether, Bis[3-(4-aminophenoxy)phenyl]ether, Bis[4-(3-aminophenoxy)phenyl]ether, Bis[4-(4-aminophenoxy)phenyl]ether, Bis[3-(3-aminophenoxy)phenyl]ketone, Bis[3-(4-aminophenoxy)phenyl]ketone, Bis[4-(3-aminophenoxy)phenyl]ketone, Bis[4-(4-aminophenoxy)phenyl]ketone, Bis[3-(3-aminophenoxy)phenyl]sulfide, Bis[3-(4-aminophenoxy)phenyl]sulfide, Bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]sulfone, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy)phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[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,A polyimide film comprising one or more selected from the group consisting 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.

11. In Paragraph 1, A polyimide film in which the diamine monomer contains 5 mol% or more of 1,4-diaminobenzene (PPD) based on 100 mol% of the total diamine monomer.

12. In Paragraph 1, The above polyimide film is a polyimide film comprising a cured product of a composition for manufacturing a polyimide film.

13. A composition for manufacturing a polyimide film comprising: a polyamic acid solution comprising a polyamic acid having a dianhydride monomer and a diamine monomer as polymerization units; and an imidization solution; and The above composition comprises at least 60 parts by weight of the imidization solution based on 100 parts by weight of the polyamic acid solution, and The relative thickness deviation (R-difference) of the above polyimide film is 25% or less, and The above thickness relative deviation (R-difference) is a value calculated by dividing the thickness deviation by the average thickness of the film and multiplying by 100 (%), and the above thickness deviation is the difference between the maximum thickness value and the minimum thickness value among the thicknesses measured using a film tester along the width direction of the film. A composition for manufacturing a polyimide film, wherein the thickness of the polyimide film is 1 to 10 μm.

14. In Paragraph 13, A composition for manufacturing a polyimide film, wherein the above polyimide film satisfies Equation 2 below: [Equation 2] |L MD - L TD | < 0.02 mN / cm In the above Equation 2, L MD is the loop stiffness value of the film in the machine transport direction, and L TD is the loop stiffness value in the width direction of the film, and The above loop stiffness value was measured by using a loop stiffness tester to fold the film into a loop and compressing it in the diameter direction of the loop, under conditions of a sample width of 10 mm, a loop length of 50 mm, and a compression distance of 10 mm.

15. In Paragraph 13, The relative standard deviation of the thickness of the above polyimide film is 6% or less, and A composition for manufacturing a polyimide film, wherein the above-mentioned relative standard deviation of thickness is a value calculated by dividing the standard deviation of thickness by the average thickness of the film and multiplying by 100 (%), the standard deviation of thickness is the standard deviation of thickness values ​​measured at multiple points in the width direction of the film according to Equation 1 below, and the average thickness is the value obtained by dividing the sum of thickness values ​​measured at multiple points along the width direction of the film by the number of measurements: [Equation 1] In the above Equation 1, is an individual data value, and μ is the mean, and N is the total number of data.

16. In Paragraph 13, A composition for manufacturing a polyimide film, wherein the above imidization solution contains 80 to 200 mol% of a catalyst based on 100 mol% of the polyamic acid.

17. In Paragraph 16, A composition for manufacturing a polyimide film, wherein the catalyst comprises one or more selected from the group consisting of pyridine, isoquinoline, beta-picoline, trimethylamine, triethylenediamine, and dimethylaniline.

18. In Paragraph 13, A composition for manufacturing a polyimide film, wherein the above imidization solution contains 650 to 1,200 mol% of a dehydrating agent based on 100 mol% of the polyamic acid.

19. In Paragraph 18, A composition for manufacturing a polyimide film, wherein the above-mentioned dehydrating agent comprises one or more selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, and benzoic anhydride.

20. A flexible circuit board comprising a polyimide film according to any one of claims 1 to 12.

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