Polyimide film and method for producing the same

Abstract

The present invention relates to a thick polyimide film with a reduced number of bubbles, high elasticity, and controlled surface roughness, and a method for manufacturing the polyimide film including the same. The polyimide film is obtained by imidizing a polyamic acid solution containing a dianhydride acid component including pyromellitic dianhydride (PMDA) and a diamine component composed of diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD), and includes spherical silica particles and a phosphorus-based compound.

Description

[Technical Field]

[0001] The present invention relates to a polyimide film, and more particularly to a thick polyimide film having high elasticity, controlled surface roughness, and a reduced number of bubbles in the produced film, and a method for producing the same. [Background technology]

[0002] Polyimide (PI) is a polymeric material that possesses the highest levels of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials, based on imide rings with excellent chemical stability along with a rigid aromatic main chain. Polyimide film is attracting attention as a material for a variety of electronic devices that require the above-mentioned properties. Currently, most polyimides dissolve in organic solvents in the form of polyamic acid, but do not dissolve in the form of polyimide. Therefore, polyimides are generally produced by using a polyamic acid solution, drying the solution to obtain the desired film, molded product, or coating film, and then heating the resulting film to imidize it.

[0003] Recently, however, thermal stresses that occur during the cooling process of polyimide films and their laminates from the imidization temperature to room temperature have often caused serious problems such as curling, film peeling, and cracking. In particular, with the rapid increase in the density of electronic circuits, problems caused by thermal stresses have become a serious concern in the adoption of multilayer wiring boards. Even if thermal stresses do not cause film peeling or cracking, residual thermal stresses in multilayer boards significantly reduce the reliability of devices. One approach to reducing the effects of thermal stress is to reduce the expansion of polyimides. However, polyimides with low thermal expansion coefficients generally have a rigid, linear main chain structure, which results in poor water vapor permeability and a tendency to foam under certain film-forming conditions. This means that dense molecular packing reduces the film's water vapor permeability, leading to the frequent formation of bubbles (air bubbles, etc.) inside the film during the film-forming process. The formation of these bubbles not only adversely affects the surface roughness of the resulting polyimide film, but can also reduce the overall electrical, optical, and mechanical properties of the polyimide film. Therefore, there is a need for a method that can reduce bubbles in polyimide films while maintaining the inherent properties of polyimide, such as heat resistance, which exhibits a low expansion coefficient, and also has high elasticity and low roughness. The matters described in the above background art are intended to help understand the background of the invention, and may include matters that are not prior art already known to those with ordinary skill in the field to which this technology belongs. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, an object of the present invention is to provide a thick polyimide film with high elasticity and controlled surface roughness. However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0005] In order to achieve the above object, one aspect of the present invention provides a polyamic acid polymer obtained by imidizing a polyamic acid solution containing a dianhydride acid component including pyromellitic dianhydride (PMDA) and a diamine component composed of diaminodiphenyl ether (4,4'-oxydianiline, ODA) and paraphenylene diamine (PPD), The content of the paraphenylenediamine (PPD) is 40 mol% or more and 55 mol% or less, and the content of the diaminodiphenyl ether (ODA) is 45 mol% or more and 60 mol% or less, based on 100 mol% of the total content of the diamine components; A polyimide film containing spherical silica particles and a phosphorus (P)-based compound is provided. Another aspect of the present invention provides the above polyimide film, wherein the spherical silica particles have an average diameter of 1 μm or less. In yet another aspect of the present invention, there is provided the polyimide film, wherein the phosphorus-based compound is contained in an amount of more than 0.1 wt % and less than 3 wt % based on the solid content of the dianhydride acid component and the diamine component. In yet another aspect of the present invention, there is provided the polyimide film, wherein the phosphorus-based compound is at least one selected from the group consisting of triphenyl phosphate (TPP), trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate. In yet another aspect, the present invention provides the above polyimide film, wherein the polyimide film has an elastic modulus of 5 GPa or more, a surface roughness of 0.005 μm or less, and a thickness of 70 μm or more. Yet another aspect of the present invention is a method for manufacturing a 1m 2 To provide a polyimide film having less than 50 bubbles per film. Yet another aspect of the present invention relates to a process for producing a polyamic acid, comprising: (a) a first step of polymerizing a dianhydride acid component including pyromellitic dianhydride (PMDA) and a diamine component including diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) in an organic solvent; (b) a second step of adding and mixing spherical silica particles having an average diameter of 1 μm or less to the polyamic acid of the first step; (c) a third step of adding an imidization catalyst and a phosphorus (P)-based compound to the polyamic acid of the second step and mixing them; (c) a fourth step of imidizing the polyamic acid of the third step, The present invention provides a method for producing a polyimide film, in which the content of paraphenylenediamine (PPD) is 40 mol % or more and 55 mol % or less, and the content of diaminodiphenyl ether (ODA) is 45 mol % or more and 60 mol % or less, based on 100 mol % of the total content of the diamine components. Yet another aspect of the present invention provides the method for producing a polyimide film, wherein the second step comprises adding a pyromellitic dianhydride (PMDA) solution to adjust the final viscosity to 100,000 to 120,000 cP. In yet another aspect of the present invention, there is provided a method for producing a polyimide film, wherein the phosphorus-based compound comprises more than 0.1 wt % and less than 3 wt % of the dianhydride acid component and the diamine component based on the solid content. In yet another aspect of the present invention, there is provided the method for producing the polyimide film, wherein the phosphorus-based compound is at least one selected from the group consisting of triphenyl phosphate (TPP), trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate. In yet another aspect, the present invention provides a method for producing the polyimide film, wherein the polyimide film has an elastic modulus of 5 GPa or more, a surface roughness of 0.005 μm or less, and a thickness of 70 μm or more. Yet another aspect of the present invention provides a protective film comprising the polyimide film. Yet another aspect of the present invention provides a carrier film comprising the polyimide film. [Effects of the Invention]

[0006] The present invention provides a polyimide film having a thickness of 70 μm or more, an elastic modulus of 5 GPa or more, a surface roughness of 0.005 μm or less, and a thickness of 70 μm or more, by providing a polyimide film containing spherical silica particles and a phosphorus-based compound, in which the composition ratio and solid content of a diamine component are adjusted. In addition, although the produced polyimide film was relatively thick, with a film thickness of 70 μm or more, the number of bubbles in the film was 50 / m 2 It was observed that the amount of bubbles observed due to the change in the content of the phosphorus-based compound was less than 100%, and a high-thickness film of excellent quality was obtained without bubbles. Such polyimide films not only have excellent mechanical properties such as high elasticity, but also have low surface roughness and suppressed bubble formation, resulting in particularly improved surface quality, making them applicable to fields requiring polyimide films with such diverse properties. DETAILED DESCRIPTION OF THE INVENTION

[0007] The terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that the inventor can appropriately define the concept of the term in order to best explain his or her invention. Therefore, it should be understood that the configuration of the embodiment described in this specification is merely one of the most preferred embodiments of the present invention and does not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can replace them at the time of this application.

[0008] In this specification, the singular expression includes the plural expression unless the context clearly indicates otherwise. It should be understood that in this specification, the terms "comprise," "comprise," or "have" are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. As used herein, "dianhydride acid" is intended to include precursors or derivatives thereof, which may not technically be dianhydrides, but which nevertheless must react with diamines to form polyamic acids, which are then converted back to polyimides. Whenever an amount, concentration, or other value or parameter is given herein as a range, a preferred range, or a list of upper and lower preferred values, it should be understood to specifically disclose all ranges formed by any pair of any upper range limit or preferred value, and any lower range limit or preferred value, regardless of whether ranges are otherwise disclosed. Where a range of numerical values ​​is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values ​​recited when defining a range.

[0009] A polyimide film according to one embodiment of the present invention is obtained by imidizing a polyamic acid solution containing a dianhydride acid component including pyromellitic dianhydride (PMDA) and a diamine component consisting of diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD). The polyimide composition contains paraphenylenediamine (PPD) in an amount of 40 to 55 mol % based on 100 mol % of the total diamine component, and diaminodiphenyl ether (ODA) in an amount of 45 to 60 mol % based on 100 mol % of the total diamine component. The composition also contains spherical silica particles and a phosphorus (P)-based compound. As paraphenylenediamine (PPD) is a rigid monomer, the polyimide synthesized has a more linear structure as the content of PPD increases, which contributes to improving the mechanical properties of the polyimide, such as its elastic modulus. If paraphenylenediamine (PPD) is used at less than 40 mol% (if diaminodiphenyl ether (ODA) is used at more than 60 mol%) based on the total amount of diamine components, the elastic modulus of thick polyimide films (film thickness of 70 μm or more) may decrease. Furthermore, when paraphenylenediamine is used in an amount exceeding 55 mol% (when diaminodiphenyl ether (ODA) is used in an amount less than 45 mol%) based on the total amount of diamine components, especially when the solid content exceeds 15 wt%, gelation due to secondary bonds may occur, making it difficult to produce a thick polyimide film.

[0010] On the other hand, thick polyimide films containing paraphenylenediamine (PPD) tend to develop bubbles more frequently as their thickness increases. This increase in bubble formation is thought to be due to the fact that as the paraphenylenediamine (PPD) content increases, the synthesized polyimide chains become more linear, and the linear polyimide chains have stronger bonds between them, making it difficult for the solvent and water to evaporate. Bubbles formed in polyimide films are a quality defect that significantly affects the appearance and mechanical properties of the polyimide film, and even if the produced polyimide film has excellent other properties, a polyimide film with a large number of bubbles is difficult to apply to actual products. Therefore, we added a phosphorus-based compound with plasticizer properties that can increase the flexibility of polyimide chains by adding free volume to the strong bonds between polyimide chains induced by paraphenylenediamine (PPD).We confirmed that the addition of this phosphorus-based compound significantly reduced the number of bubbles that formed in the polyimide film.

[0011] According to another embodiment of the present invention, the polyimide film may contain spherical silica particles having an average diameter of 1 μm or less, preferably 800 nm or less, and more preferably 500 nm or less. Spherical silica particles are added to polyimide films to create surface roughness, imparting anti-blocking properties that prevent polyimide films from adhering to each other during production or use. Silica particles are commonly used as an additive for polyimide films, and spherical silica particles in particular have superior anti-blocking properties compared to amorphous silica particles. If the average diameter of the spherical silica particles exceeds 1 μm, the surface roughness increases, inducing scratches on the surface of the object that comes into contact with the polyimide film, resulting in product defects. If the average diameter of the spherical silica particles is less than 0.1 μm, the anti-blocking properties that prevent film blocking will not be exhibited. The spherical silica particles can be contained in an amount of 1,000 to 3,000 ppm based on the weight of the polyimide film, but is not limited to this.Usually, if the spherical silica particles are used in an amount exceeding 3,000 ppm, the particles will aggregate together and form bonds in the film, while if they are used in an amount less than 1,000 ppm, the films will stick together after surface treatment, making it difficult to proceed with the winding step.

[0012] According to another embodiment of the present invention, the phosphorus-based compound having plasticizer properties used to suppress bubble formation may be contained in an amount of more than 0.1 wt % and less than 3 wt % based on the solid content of the dianhydride acid component and diamine component used in the synthesis of the polyimide, with 0.5 to 2.5 wt % being preferred, and 2.0 to 2.5 wt % being even more preferred. If the phosphorus-based compound is contained in an amount of 0.1 wt % or less, the bubble formation suppression effect is insufficient, and if it is contained in an amount of 3 wt % or more, the elastic modulus of the polyimide film is reduced. Phosphorus compounds that are used include triphenyl phosphate (TPP), ammonium polyphosphate, trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate. In particular, it is preferable to use at least one of triphenyl phosphate (TPP) and ammonium polyphosphate, but the present invention is not limited thereto. Any phosphorus-based compound having plasticizer properties that can increase flexibility between polyimide chains by adding free volume and that can contribute to suppressing bubble formation can be used.

[0013] The polyimide film according to the embodiment of the present invention is a thick polyimide film having high elasticity and low roughness properties at the same time, with an elastic modulus of 5 GPa or more, a surface roughness of 0.005 μm or less, and a thickness of 70 μm or more. The polyimide film exhibits an excellent elastic modulus of 5 GPa or more by adjusting the content of paraphenylenediamine (PPD). Such a polyimide film with an excellent elastic modulus is applicable to various fields, and is particularly suitable for carrier films and protective films. The polyimide film also exhibits low surface roughness, which is directly related to the average diameter of the spherical silica particles. Generally, the larger the average diameter of the spherical silica particles, the greater the surface roughness. When spherical silica particles with an average diameter exceeding 1 μm are used, the surface roughness exceeds 0.005 μm. As mentioned above, such an increase in surface roughness can cause scratches on the surface of an object in contact with the polyimide film, resulting in product defects. In addition, the polyimide film is preferably a thick polyimide film having a thickness of 70 μm or more, and the thickness of the polyimide film is preferably 75 μm or more. The polyimide film is 1 m 2 The number of bubbles per coating is less than 50, and the number of bubbles decreases as the content of the phosphorus-based compound added increases. By appropriately adjusting the content of the phosphorus-based compound, it is possible to minimize the number of bubbles (no bubbles are observed) while maintaining an elastic modulus and surface roughness suitable for product application.

[0014] Another embodiment of the present invention is a process for producing a polyamic acid by (a) polymerizing a dianhydride acid component including pyromellitic dianhydride (PMDA) and a diamine component including diaminodiphenyl ether (ODA) and paraphenylenediamine (PPD) in an organic solvent in a first step; (b) a second step of adding and mixing spherical silica particles having an average diameter of 1 μm or less to the polyamic acid of the first step; (c) a third step of adding an imidization catalyst and a phosphorus (P)-based compound to the polyamic acid of the second step and mixing them; (c) a fourth step of imidizing the polyamic acid of the third step, The present invention relates to a method for producing a polyimide film, wherein the content of the paraphenylenediamine (PPD) is 40 mol% or more and 55 mol% or less, and the content of the diaminodiphenyl ether (ODA) is 45 mol% or more and 60 mol% or less, based on 100 mol% of the total content of the diamine components. In other words, in the method for producing a polyimide film of the present invention, spherical silica particles are added to and mixed with a polyamic acid solution containing a dianhydride acid component and a diamine component, followed by the addition and mixing of an imidization catalyst and a phosphorus-based compound, followed by the subsequent imidization reaction to form a polyimide film. The polyamic acid can be imidized using either thermal or chemical imidization, or a combination of thermal and chemical imidization methods. Thermal imidization is a method in which the imidization reaction is induced using a heat source such as hot air or an infrared dryer without using a chemical catalyst, while chemical imidization is a method in which a dehydrating agent and an imidization agent are used. The second step may be carried out by adding a pyromellitic dianhydride (PMDA) solution to a final viscosity of 100,000 to 120,000 cP, but is not limited thereto. The phosphorus-based compound may be present in an amount of more than 0.1 wt% and less than 3 wt% based on the solid content of the dianhydride acid component and the diamine component. Examples of the phosphorus-based compound include triphenyl phosphate (TPP), trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate. While it is particularly preferred to use at least one of triphenyl phosphate (TPP) and ammonium polyphosphate, the present invention is not limited thereto. Any phosphorus-based compound that has plasticizer properties and can contribute to the suppression of bubble formation by providing free volume and increasing flexibility between polyimide chains can be used.

[0015] The polyimide film produced by the above production method had an elastic modulus of 5 GPa or more, a surface roughness of 0.005 μm or less, and a thickness of 70 μm or more. The produced polyimide film is suitable for use as a protective film or a carrier film, but is not limited thereto, and can be used in various fields where the properties of the produced polyimide film can be applied. [Example]

[0016] The functions and effects of the present invention will be described in more detail below through specific manufacturing examples and examples of the present invention, however, these manufacturing examples and examples are presented only as examples of the present invention and do not limit the scope of the invention.

[0017] Manufacturing example: Manufacturing of polyimide film The polyimide film of the present invention can be prepared by a conventional method known in the art. First, the dianhydride and diamine components are reacted in an organic solvent to obtain a polyamic acid solution. The solvent is typically an aprotic solvent, such as an amide solvent, for example, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, or a combination thereof. The dianhydride acid and diamine components may be added in the form of powder, lump, or solution. It is preferred that they are added in the form of powder at the beginning of the reaction to allow the reaction to proceed, and then added in the form of a solution to control the polymerization viscosity. Fillers may also be added to improve various properties of the polyimide film, including, but not limited to, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, etc. The resulting polyamic acid solution is mixed with an imidization catalyst and a dehydrating agent and then applied to a support. Examples of catalysts that can be used include, but are not limited to, tertiary amines (e.g., isoquinoline, β-picoline, pyridine, etc.), and examples of dehydrating agents include, but are not limited to, acid anhydride. Furthermore, examples of supports that can be used include, but are not limited to, glass plates, aluminum foils, rotating stainless steel belts, and stainless steel drums. The film coated on the support is gelled on the support by dry air and heat treatment. The gelled film is separated from the support and heat treated to complete drying and imidization. After the heat treatment, the film is further heat treated under a certain tension to remove residual stress inside the film that has occurred during the film formation process.

[0018] Specifically, 500ml of DMF was added to a reactor equipped with a stirrer and nitrogen inlet / outlet pipes while injecting nitrogen, and the reactor temperature was set to 30°C. Pyromellitic dianhydride (PMDA), diaminodiphenyl ether (ODA), and paraphenylenediamine (PPD) were then added in a controlled ratio and completely dissolved. The reactor temperature was then raised to 40°C under a nitrogen atmosphere, and stirring was continued for 120 minutes while heating, producing polyamic acid with a primary reaction viscosity of 1,500cP. To the polyamic acid thus produced, spherical silica particles with an average diameter of 500 nm were added in an amount of 1,500 ppm based on the weight of the polyimide film, and then a pyromellitic dianhydride (PMDA) solution was added and stirred to a final viscosity of 100,000 to 120,000 cP. To the final polyamic acid prepared in this manner, a catalyst, a dehydrating agent, and a phosphorus-based compound, triphenyl phosphate (TPP), were added by adjusting the content, and then a thick polyimide film was prepared using an applicator.

[0019] Examples and Comparative Examples The product was produced according to the production example described above, and only pyromellitic dianhydride (PMDA) was used as the dianhydride acid component. 100 mol % of the diamine component was reacted based on 100 mol % of the dianhydride acid component. The composition ratio of the diamine components, paraphenylenediamine (PPD) and diaminodiphenyl ether (ODA), was 55 mol% paraphenylenediamine (PPD) and 45 mol% diaminodiphenyl ether (ODA) when the total diamine content was 100 mol%. As shown in Table 1 below, the content of triphenyl phosphate (TPP) was 0.5 to 3 wt % based on the solid content of the dianhydride acid component and the diamine component, and the thickness of the produced polyimide films was all 75 μm.

[0020] [Table 1]

[0021] The surface roughness of the polyimide films prepared in all examples and comparative examples was measured as an arithmetic mean roughness (Ra) value using a film roughness analyzer from Kosaka Laboratory Ltd. The measured surface roughness of the polyimide films of the Examples and Comparative Examples was all 0.005 μm or less. In addition, the elastic modulus of the polyimide films prepared in all examples and comparative examples was measured using an Instron testing apparatus (Standard Instron testing apparatus) in accordance with ASTM D 882, and the average value was calculated. The average number of bubbles was determined by first photographing the polyimide film using a film defect analyzer equipped with a video device, and then directly checking the photographed image of the defects in the polyimide film with the naked eye. A film of a certain width and length is taken as a sample and the number of bubbles is measured. 2 The number of bubbles per unit was calculated.

[0022] According to the measurement results, in Examples 1 to 5 in which triphenyl phosphate (TPP) was added at a content of 0.5% by weight to 2.5% by weight, the thickness of the polyimide film was significantly higher than that of Comparative Example 1 (number of bubbles: 1 m ) in which no triphenyl phosphate (TPP) was used. 2 and Comparative Example 2 (number of bubbles: 1 m ) containing 0.1% by weight of triphenyl phosphate (TPP). 2 The number of bubbles was significantly reduced compared to the previous method (50 bubbles per bubble). In particular, by increasing the content of triphenyl phosphate (TPP) from 0.5 wt% to 2.5 wt%, the number of bubbles decreased by 1 m 2 The number of cases decreased from 18-20 per case to 0. Furthermore, when the triphenyl phosphate (TPP) content was 0.5 wt % to 2.5 wt % (Examples 1 to 5), the elastic modulus tended to decrease slightly compared to Comparative Examples 1 and 2 (5.91 GPa and 5.89 GPa, respectively). However, the elastic modulus of the polyimide film was 5.15 GPa to 5.82 GPa, which was above 5 GPa, and it was confirmed that there was no problem in applying the produced polyimide film to products. When the triphenyl phosphate (TPP) content was used in excess of 3 wt. % or more (Comparative Examples 3 to 5), the number of bubbles remained at 0, as in Example 5, but the elastic modulus significantly decreased to less than 5 GPa. The decrease in modulus with increasing triphenyl phosphate (TPP) content is thought to be due to the plasticizer properties of TPP.

[0023] The examples of the polyimide film and method for manufacturing the polyimide film of the present invention are merely preferred examples that will enable those skilled in the art to easily practice the present invention, and the present invention is not limited to the above examples, and the scope of the present invention is not limited by these examples. Therefore, the true technical scope of the present invention must be determined by the technical spirit of the appended claims. Furthermore, it is obvious to those skilled in the art that various substitutions, modifications, and changes are possible within the scope of the present invention, and it is obvious that parts that can be easily modified by those skilled in the art are also included in the scope of the present invention. [Industrial Applicability]

[0024] The polyimide film of the present invention not only has excellent mechanical properties such as high elasticity, but also has low surface roughness and suppressed bubble formation, thereby improving surface quality in particular, and is therefore applicable to fields where polyimide films with such diverse properties are required.

Claims

1. A polyimide film obtained by imidizing a polyamic acid solution containing a dianhydride acid component made of pyromellitic dianhydride (PMDA) and a diamine component made of diaminodiphenyl ether (4,4'-oxydianiline (ODA)) and paraphenylene diamine (PPD), the content of the paraphenylenediamine (PPD) is 40 mol% or more and 55 mol% or less, and the content of the diaminodiphenyl ether (ODA) is 45 mol% or more and 60 mol% or less, based on 100 mol% of the total content of the diamine components; Contains spherical silica particles and a phosphorus (P)-based compound having plasticizer properties, The spherical silica particles are contained in an amount of 1,000 to 3,000 ppm based on the weight of the polyimide film, the phosphorus (P)-based compound having plasticizer properties is contained in an amount of more than 0.1 wt % and less than 3 wt % based on the solid content of the dianhydride acid component and the diamine component; The elastic modulus is 5 GPa or more, The surface roughness is 0.005 μm or less, and the thickness is 70 μm or more, 1 m 2 There are less than 50 bubbles per Polyimide film.

2. 2. The polyimide film according to claim 1, wherein the spherical silica particles have an average diameter of 1 μm or less.

3. 2. The polyimide film of claim 1, wherein the phosphorus (P)-based compound is at least one selected from the group consisting of triphenyl phosphate (TPP), trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate.

4. A method for producing a polyimide film (a) a first step of polymerizing a dianhydride acid component consisting of pyromellitic dianhydride (PMDA) and a diamine component consisting of diaminodiphenyl ether (4,4'-oxydianiline (ODA)) and paraphenylene diamine (PPD) in an organic solvent to produce a polyamic acid; (b) a second step of adding and mixing spherical silica particles having an average diameter of 1 μm or less to the polyamic acid of the first step; (c) a third step of adding and mixing an imidization catalyst and a phosphorus (P)-based compound having plasticizer properties to the polyamic acid of the second step; (d) a fourth step of imidizing the polyamic acid of the third step, the content of the paraphenylenediamine (PPD) is 40 mol% or more and 55 mol% or less, and the content of the diaminodiphenyl ether (ODA) is 45 mol% or more and 60 mol% or less, based on 100 mol% of the total content of the diamine components; The spherical silica particles are contained in an amount of 1,000 to 3,000 ppm based on the weight of the polyimide film, the phosphorus (P)-based compound having plasticizer properties is contained in an amount of more than 0.1 wt % and less than 3 wt % based on the solid content of the dianhydride acid component and the diamine component; The elastic modulus is 5 GPa or more, The surface roughness is 0.005 μm or less, and the thickness is 70 μm or more, 1 m 2 There are less than 50 bubbles per A method for producing polyimide film.

5. 5. The method for producing a polyimide film according to claim 4, wherein the second step comprises adding a pyromellitic dianhydride (PMDA) solution to a final viscosity of 100,000 to 120,000 cP.

6. 5. The method for manufacturing a polyimide film according to claim 4, wherein the phosphorus (P)-based compound is at least one selected from the group consisting of triphenyl phosphate (TPP), trixylenyl phosphate (TXP), tricresyl phosphate (TCP), resorcinol diphenyl phosphate, and ammonium polyphosphate.

7. The polyimide film according to any one of claims 1 to 3, which is used as a protective film or a carrier film.

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