Polyimide precursor composition and polyimide film containing the same

Abstract

The present invention provides a polyimide film comprising a block copolymer including: a first block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing biphenyltetracarboxylic dianhydride and a diamine component containing paraphenylenediamine; a second block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing biphenyltetracarboxylic dianhydride and a diamine component containing m-tolidine; and a third block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing pyromellitic dianhydride (PMDA) and a diamine component containing m-tolidine.

Description

Technical Field

[0001] The present invention relates to a polyimide precursor composition and a polyimide film having excellent high heat resistance characteristics, low dielectric characteristics, and dimensional stability characteristics, which are produced using the polyimide precursor composition.

Background Art

[0002] Polyimide (PI) is a polymer material having the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials, based on an imide ring with a very excellent chemical stability together with a rigid aromatic main chain. In particular, due to its excellent insulating properties, that is, excellent electrical properties such as a low dielectric constant, it has been attracting attention as a high-functional polymer material in fields such as electricity, electronics, and optics. Recently, with the weight reduction and miniaturization of electronic products, highly integrated and flexible thin circuit boards have been actively developed.

[0003] Such thin circuit boards tend to be widely used in a structure in which a circuit including a metal foil is formed on a polyimide film that is easy to bend while having excellent heat resistance, low temperature resistance, and insulating properties. As such a thin circuit board, a flexible metal foil laminate is mainly used. As an example, a flexible copper clad laminate (FCCL) using a thin copper plate for the metal foil is included. In addition, polyimide is also used as a protective film or an insulating film of a thin circuit board. On the other hand, recently, as various functions are incorporated in electronic devices, the electronic devices are required to have a high operation speed and a high communication speed. In order to meet this requirement, a thin circuit board capable of high-speed communication at a high frequency has been developed.

[0004] To realize high-frequency, high-speed communication, an insulator with high impedance that can maintain electrical insulation even at high frequencies is necessary. Since impedance is inversely proportional to the frequency and dielectric constant (Dk) formed in the insulator, the dielectric constant must be as low as possible to maintain insulation even at high frequencies. However, in the case of ordinary polyimides, the dielectric properties are not currently at a level that is good enough to maintain sufficient insulation for high-frequency communication. Furthermore, it is known that the lower the dielectric properties of an insulator, the more it is possible to reduce the generation of undesirable stray capacitance and noise in thin circuit boards, thereby largely eliminating the causes of communication delay. Therefore, polyimide with low dielectric properties is currently recognized as the most important factor in the performance of thin circuit boards.

[0005] In particular, in the case of high-frequency communication, dielectric dissipation due to polyimide inevitably occurs. The dielectric dissipation factor (Df) represents the degree of electrical energy wasted by the thin circuit board and is closely related to the signal transmission delay that determines the communication speed. Therefore, maintaining the dielectric dissipation factor of polyimide as low as possible is recognized as an important factor in the performance of thin circuit boards. Furthermore, the more moisture a polyimide film contains, the larger its dielectric constant becomes, and the higher its dielectric loss rate. While polyimide films are suitable as materials for thin circuit boards due to their excellent inherent properties, they are relatively vulnerable to moisture due to the polar imide groups. This can lead to a decrease in insulation properties. Therefore, the current need is to develop polyimide films with dielectric properties, particularly low dielectric loss, while maintaining the unique mechanical, thermal, and dimensional stability characteristics of polyimide at a certain level. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Republic of Korea Patent Publication No. 10-2015-0069318 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Therefore, in order to solve the above problems, the objective is to provide a polyimide film that combines excellent high heat resistance, low dielectric properties, and dimensional stability, as well as a polyamide precursor composition for producing the same. Therefore, the substantial objective of the present invention is to provide specific embodiments thereof. [Means for solving the problem]

[0008] To achieve the above objective, one embodiment of the present invention provides a first block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride component containing biphenyltetracarboxylic dianehydride (BPDA) and a diamine component containing paraphenylenediamine (PPD), A second block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride component containing biphenyltetracarboxylic dianehydride and a diamine component containing m-tolidine, A block copolymer comprising a third block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing pyromeretic dianehydride (PMDA) and a diamine component containing m-tolidine, We provide polyimide films.

[0009] Another embodiment of the present invention includes the polyimide film and a thermoplastic resin layer, We provide multilayer films. A further embodiment of the present invention includes the polyimide film and an electrically conductive metal foil. We provide flexible metal foil laminates. Yet another embodiment of the present invention includes the flexible metal foil laminate, We provide electronic components.

[0010] A further embodiment of the present invention involves a first block obtained by reacting a dianhydride acid component containing biphenyltetracarboxylic dianehydride (BPDA) with a diamine component containing paraphenylenediamine (PPD), A second block obtained by imidizing a dianhydride acid component containing biphenyltetracarboxylic dianehydride with a diamine component containing m-tolidine, A block copolymer comprising a third block obtained by reacting a dianhydride acid component containing pyromeretic dianehydride (PMDA) with a diamine component containing m-tolidine, A polyimide precursor composition is provided. [Effects of the Invention]

[0011] As described above, the present invention relates to a polyimide fiber comprising specific components and specific composition ratios. By providing polyimide films with excellent high heat resistance, low dielectric properties, and dimensional stability properties through films and polyamide precursor compositions for producing them, these films can be usefully applied to a variety of fields where such properties are required, particularly to electronic components such as flexible metal foil laminates. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in more detail below. Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention. Therefore, the configurations of the embodiments described in this specification are merely one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. It should be understood that there can be various equivalents and variations that can replace these at the time of this application.

[0013] In this specification, the singular forms include plural forms unless the context clearly indicates otherwise. In this specification, terms such as "including", "comprising", or "having" are intended to specify the presence of implemented features, numbers, steps, components, or combinations thereof, and it should be understood that they do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, when a quantity, concentration, or other value or parameter is given as a list of ranges, preferred ranges, or preferred upper and lower limit values, it should be understood that all ranges formed by any upper limit value or preferred value of any arbitrary upper range and any lower limit value or preferred value of any arbitrary lower range are specifically disclosed, regardless of whether the range is disclosed separately. When a numerical range is mentioned in this specification, unless otherwise stated, that range is intended to include its endpoints and all integers and fractions within that range. It is intended that the scope of the present invention is not limited to the specific values mentioned when defining the range.

[0014] In this specification, "dianhydride acid" is intended to include its precursors or derivatives, which may not technically be dianhydride acids, but nevertheless should react with diamine to form polyamic acid, and this polyamic acid should be converted back to polyimide. In this specification, "diamine" is intended to include its precursors or derivatives, which may not technically be diamines, but nevertheless should react with dianhydride to form polyamic acid, and this polyamic acid should be converted back to polyimide. The polyimide film according to the present invention includes a first block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing biphenyltetracarboxylic dianhydride (BPDA) and a diamine component containing paraphenylenediamine (PPD), a second block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing biphenyltetracarboxylic dianhydride and a diamine component containing m-tolidine, and a third block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing pyromellitic dianhydride (PMDA) and a diamine component containing m-tolidine, and can include a block copolymer containing these.

[0015] For example, the first block is obtained by subjecting a polyamic acid derived from a polymer of biphenyltetracarboxylic dianhydride and paraphenylenediamine to an imidization reaction. The second block is obtained by subjecting a polyamic acid derived from a polymer of biphenyltetracarboxylic dianhydride and m-tolidine to an imidization reaction, and the third block is obtained by subjecting a polyamic acid derived from a polymer of pyromellitic dianhydride and m-tolidine to an imidization reaction. The m-tolidine has a methyl group exhibiting hydrophobicity, which contributes to the low moisture absorption property of the polyimide film and the low dielectric property of the polyimide film resulting therefrom.

[0016] In one embodiment, the polyimide film is obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component composed of biphenyltetracarboxylic dianhydride and pyromellitic dianhydride and a diamine component composed of paraphenylenediamine and m-tolidine. This is because the polyimide film includes the first block, the second block, and the third block, or is composed of a block copolymer composed of the first block, the second block, and the third block.

[0017] In one embodiment, based on a total diamine content of 100 mol% of the polyimide film, the content of m-tolidine may be 25 mol% or more and 40 mol% or less, and the content of paraphenylenediamine may be 60 mol% or more and 75 mol% or less. Preferably, based on a total diamine content of 100 mol% of the polyimide film, the content of m-tolidine may be 30 mol% or more and 40 mol% or less, and the content of paraphenylenediamine may be 60 mol% or more and 70 mol% or less.

[0018] Furthermore, based on a total content of 100 mol% of dianhydric acid components in the polyimide film, the content of biphenyltetracarboxylic dianehydride may be 50 mol% or more and 65 mol% or less, and the content of pyromeretic dianehydride may be 35 mol% or more and 50 mol% or less. Preferably, based on a total content of 100 mol% of dianhydric acid components in the polyimide film, the content of biphenyltetracarboxylic dianehydride may be 50 mol% or more and 60 mol% or less, and the content of pyromeretic dianehydride may be 40 mol% or more and 50 mol% or less.

[0019] The polyimide chain derived from the biphenyltetracarboxylic dianehydride of the present invention has a structure called a charge transfer complex (CTC), that is, a regular linear structure in which electron donors and electron acceptors are located in close proximity to each other, thereby enhancing intermolecular interactions. This structure has the effect of preventing hydrogen bonding with moisture, thus influencing the reduction of the moisture absorption rate and maximizing the effect of reducing the hygroscopicity of the polyimide film. In one specific example, the dianhydride component may additionally include pyromeretic dianehydride. Pyromeretic dianehydride is a dianhydride component having a relatively rigid structure and is preferred in that it can impart appropriate elasticity to the polyimide film.

[0020] For a polyimide film to simultaneously satisfy appropriate elasticity and moisture absorption, the content ratio of dianhydride acids is particularly important. For example, the lower the content ratio of biphenyltetracarboxylic dianehydride, the less likely it is to achieve the low moisture absorption rate due to the CTC structure. Furthermore, biphenyltetracarboxylic dianehydrides contain two benzene rings corresponding to the aromatic moiety, whereas pyromeretic dianehydrides contain two benzene rings corresponding to the aromatic moiety. It contains one corresponding benzene ring.

[0021] An increase in the pyromeretic dianehydride content in the dianhydride acid component can be understood as an increase in the number of imide groups within the molecule, relative to the same molecular weight. This can be understood as an increase in the ratio of imide groups derived from the pyromeretic dianehydride to imide groups derived from biphenyltetracarboxylic dianehydride in the polyimide polymer chain. In other words, an increase in the pyromeretic dianehydride content is seen as a relative increase in imide groups in the polyimide film as a whole, making it difficult to expect a low moisture absorption rate. Conversely, if the pyromeretic dianehydride content decreases, the relatively rigid structural components decrease, which may cause the elasticity of the polyimide film to fall below the desired level.

[0022] For these reasons, if the content of biphenyltetracarboxylic dianehydride exceeds the range or the content of pyromeretic dianehydride falls below the range, the mechanical properties of the polyimide film deteriorate, making it impossible to ensure a level of heat resistance suitable for manufacturing flexible metal foil laminates. Conversely, if the content of biphenyltetracarboxylic dianehydride falls below the range, or if the content of pyromeretic dianehydride exceeds the range, it is undesirable because it is difficult to achieve appropriate levels of dielectric constant and dielectric loss rate.

[0023] In one embodiment, the content of the biphenyltetracarboxylic dianehydride in the first block may be 40 mol% or more and 55 mol% or less based on the total content of dianhydric acid components of the polyimide film (100 mol%), and the content of the biphenyltetracarboxylic dianehydride in the second block may be 10 mol% or more based on the total content of dianhydric acid components of the polyimide film (100 mol%). If the content of the biphenyltetracarboxylic dianehydride in the first block is below the range, it may be difficult to secure a sufficiently low dielectric loss rate (Df), and if it exceeds the range, it may be difficult to secure the required heat resistance.

[0024] If the content of the biphenyltetracarboxylic dianehydride in the second block is below the range mentioned above, it may be difficult to ensure a sufficiently low dielectric loss rate (Df). On the other hand, the content of the biphenyltetracarboxylic dianehydride in the second block may be 25 mol% or less, based on the total content of the dianhydride acid component of the polyimide film, which is 100 mol%.

[0025] If the content of the biphenyltetracarboxylic dianehydride in the second block exceeds the aforementioned range, it may be difficult to ensure the required heat resistance. Furthermore, all of the biphenyltetracarboxylic dianehydride in the first block may be imidized with paraphenylenediamine, and all of the biphenyltetracarboxylic dianehydride in the second block may be imidized with m-tolidine.

[0026] On the other hand, the m-tolidine content of the third block may be 10 mol% or more and 35 mol% or less, based on the total content of the diamine components of the polyimide film, which is 100 mol%. If the m-tolidine content of the third block is below the range, it may be difficult to secure a sufficiently low dielectric loss rate (Df), and if it exceeds the range, it may be difficult to secure the required heat resistance. . Furthermore, all of the m-tolidine in the third block may be imidized with pyromellitic dianehydride.

[0027] In one embodiment, the polyimide film may have a dielectric loss rate (Df) of 0.003 or less, a coefficient of thermal expansion (CTE) of 13 ppm / °C or more and 23 ppm / °C or less, and a glass transition temperature (Tg) of 320°C or more. In this regard, a polyimide film that satisfies all requirements for dielectric loss rate (Df), thermal expansion coefficient, and glass transition temperature can be used as an insulating film for flexible metal foil laminates. Furthermore, even when the manufactured flexible metal foil laminate is used as an electrical signal transmission circuit transmitting signals at high frequencies of 10 GHz or higher, its insulating stability is ensured and signal transmission delay can be minimized. A polyimide film that meets all of the above conditions is a novel polyimide film that has not been previously known, and the dielectric loss rate (Df) will be explained in detail below.

[0028] <Dielectric Loss Ratio> "Dielectric loss rate" refers to the force that is abolished by a dielectric (or insulator) when molecular friction opposes molecular motion caused by an alternating electric field. The dielectric loss rate is commonly used as an index to indicate the ease with which electric charge is lost (dielectric loss). A higher dielectric loss rate means that charge is lost more easily, while a lower dielectric loss rate means that charge is lost less easily. In other words, the dielectric loss rate is a measure of power loss, and the lower the dielectric loss rate, the more the signal transmission delay due to power loss is mitigated while maintaining a faster communication speed. This is a requirement strongly desired for polyimide films, which are insulating films, and the polyimide film according to the present invention has a dielectric loss of 0.003 or less at a very high frequency of 10 GHz.

[0029] In the present invention, the production of polyamic acid is, for example, (1) A method of polymerization by placing the entire amount of the diamine component into a solvent, and then adding the dianhydride acid component in a substantially equimolar amount to the diamine component; (2) A method of polymerization by placing the entire amount of the dianhydride acid component into a solvent, and then adding the diamine component in a substantially equimolar amount to the dianhydride acid component; (3) A method of polymerization in which, after adding some of the components of the diamine component to the solvent, some of the components of the dianhydride component are mixed with the reactant in a ratio of approximately 95 to 105 mol%, the remaining diamine component is added, followed by the remaining dianhydride component, until the diamine component and the dianhydride component are substantially equimolar; (4) A method of polymerization in which, after adding the dianhydride acid component to the solvent, a portion of the diamine compound is mixed with the reaction components in a ratio of 95 to 105 mol%, then other dianhydride acid components are added, followed by the addition of the remaining diamine components, so that the diamine components and dianhydride acid components are substantially equimolar; (5) A method of polymerization in which a portion of the diamine component and a portion of the dianhydride acid component are reacted in a solvent such that one of them is in excess to form a first composition, a portion of the diamine component and a portion of the dianhydride acid component are reacted in another solvent such that one of them is in excess to form a second composition, and then the first and second compositions are mixed to complete polymerization, wherein when forming the first composition, if the diamine component is in excess, the dianhydride acid component is in excess in the second composition, and when forming the first composition, if the dianhydride acid component is in excess, the diamine component is in excess in the second composition, and the first and second compositions are mixed so that the total amount of diamine component and dianhydride acid component used in these reactions is substantially equimolar.

[0030] In the present invention, the polymerization method of polyamic acid as described above can be defined as a random polymerization method, and the polyamic acid of the present invention produced by the process described above can be used to produce The resulting polyimide film is preferably applicable in terms of maximizing the effects of the present invention, which are to reduce dielectric loss (Df) and moisture absorption rate. However, since the polymerization method described above produces polymers with relatively short repeating units, there may be limitations in exhibiting the excellent properties of the polyimide chains derived from the dianhydride acid component. Therefore, the polymerization method of polyamic acid that is particularly preferable and usable in the present invention is the block polymerization method.

[0031] On the other hand, the solvent used to synthesize polyamic acid is not particularly limited; any solvent that can dissolve polyamic acid can be used, but an amide-based solvent is preferred. Specifically, the solvent may be an organic polar solvent, and more specifically, it may be an aprotic polar solvent, or it may be one or more selected from the group consisting of, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone (NMP), gamma-butyrolactone (GBL), and diglyme, but it is not limited to these, and can be used individually or in combination of two or more as needed.

[0032] In one example, the solvent can be N,N-dimethylformamide or N,N-dimethylacetamide, which are particularly preferred. Furthermore, in the manufacturing process of polyamic acid, fillers may be added to improve various properties of the film, such as sliding properties, thermal conductivity, corona resistance, and loop hardness. The added fillers are not particularly limited, but preferred examples include silica, titanium dioxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.

[0033] The particle size of the filler is not particularly limited and should be determined by the film characteristics to be modified and the type of filler added. Generally, the average particle size is 0.05 to 100 μm, preferably 0.1 to 75 μm, more preferably 0.1 to 50 μm, and most preferably 0.1 to 25 μm. If the particle size falls below this range, the modification effect becomes less pronounced, and if it exceeds this range, the surface properties may be severely damaged or the mechanical properties may be significantly reduced. Furthermore, there are no particular limitations on the amount of filler to be added; it should be determined based on the film characteristics to be modified and the particle size of the filler. Generally, the amount of filler to be added is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight, per 100 parts by weight of polyimide.

[0034] If the amount of filler added falls below this range, the modification effect of the filler will be less apparent, and if it exceeds this range, the mechanical properties of the film may be severely damaged. The method of adding the filler is not particularly limited, and any known method may be used. In the manufacturing method of the present invention, the polyimide film is produced by a thermal imidation method and a chemical imidation method.

[0035] Alternatively, it may be manufactured by a composite imidation method in which thermal imidation and chemical imidation are carried out in parallel. The aforementioned thermal imidation method is a method that eliminates chemical catalysts and induces the imidation reaction using a heat source such as hot air or an infrared dryer. The aforementioned thermal imidization method allows for the imidization of amic acid groups present in the gel film by heat-treating the gel film at a variable temperature in the range of 100 to 600°C, and more specifically, by heat-treating it at 200 to 500°C, or even more specifically, at 300 to 500°C.

[0036] However, even during the gel film formation process, a portion of the amic acid (approximately 0.1 mol% to 10 mol%) is imidized, allowing the polyamic acid composition to be dried at a variable temperature in the range of 50°C to 200°C, which also falls under the category of the thermal imidization method. In the case of chemical imidation, polyimide films can be manufactured using a dehydrating agent and an imidizing agent by methods known in the industry.

[0037] As an example of a composite imidation method, a polyimide film can be produced by adding a dehydrating agent and an imidizing agent to a polyamic acid solution, heating it at 80 to 200°C, preferably 100 to 180°C to partially cure and dry it, and then heating it at 200 to 400°C for 5 to 400 seconds. The polyimide film of the present invention manufactured by the manufacturing method described above may have a dielectric loss rate (Df) of 0.004 or less, a coefficient of thermal expansion (CTE) of 15 ppm / °C or less, and a glass transition temperature (Tg) of 320°C or higher. The present invention provides a multilayer film comprising the polyimide film described above and a thermoplastic resin layer, and a flexible metal foil laminate comprising the polyimide film described above and an electrically conductive metal foil.

[0038] For example, a thermoplastic polyimide resin layer can be used as the thermoplastic resin layer. The metal foil used is not particularly limited, but when the flexible metal foil laminate of the present invention is used in electronic or electrical equipment applications, it may include, for example, copper or copper alloys, stainless steel or its alloys, nickel or nickel alloys (including 42 alloys), aluminum or aluminum alloys. In general flexible metal foil laminates, rolled copper foil and electrolytic copper foil are commonly used, and these can also be preferably used in the present invention. Furthermore, the surface of these metal foils may be coated with a rust-preventive layer, a heat-resistant layer, or an adhesive layer.

[0039] In the present invention, the thickness of the metal foil is not particularly limited, and any thickness that allows it to perform its function adequately depending on the application is acceptable. The flexible metal foil laminate according to the present invention may have a structure in which a metal foil is laminated to one surface of the polyimide film, or an adhesive layer containing thermoplastic polyimide is added to one surface of the polyimide film, and the metal foil is laminated while attached to the adhesive layer. The present invention further provides an electronic component that includes the flexible metal foil laminate as an electrical signal transmission circuit. The electrical signal transmission circuit may be an electronic component that transmits signals at a high frequency of at least 2 GHz, more specifically at a high frequency of at least 5 GHz, and even more specifically at a high frequency of at least 10 GHz.

[0040] The aforementioned electronic component may, but is not limited to, a communication circuit for a mobile terminal, a communication circuit for a computer, or a communication circuit for aerospace applications. On the other hand, the polyimide precursor composition according to the present invention may include a block copolymer comprising: a first block obtained by reacting a dianhydride acid component containing biphenyltetracarboxylic dianehydride (BPDA) with a diamine component containing paraphenylenediamine (PPD); a second block obtained by reacting a dianhydride acid component containing biphenyltetracarboxylic dianehydride with a diamine component containing m-tolidine; and a third block obtained by reacting a dianhydride acid component containing pyromeretic dianehydride (PMDA) with a diamine component containing m-tolidine.

[0041] The dianhydride acid component and diamine component of the block copolymer consist solely of biphenyltetracarboxylic dianehydride, pyromeretic dianehydride, paraphenylenediamine, and m-tolidine. In one embodiment, based on a total content of 100 mol% of the diamine components of the block copolymer, the content of m-tolidine may be 25 mol% or more and 40 mol% or less, and the content of paraphenylenediamine may be 60 mol% or more and 75 mol% or less. Based on a total content of 100 mol% of the dianhydric acid components of the block copolymer, the content of biphenyltetracarboxylic dianehydride may be 50 mol% or more and 65 mol% or less, and the content of pyromeretic dianehydride may be 35 mol% or more and 50 mol% or less.

[0042] In one embodiment, the content of the biphenyltetracarboxylic dianehydride in the first block of the block copolymer may be 40 mol% or more and 55 mol% or less based on the total content of dianhydric acid components of the polyimide film (100 mol%), and the content of the biphenyltetracarboxylic dianehydride in the second block may be 10 mol% or more based on the total content of dianhydric acid components of the polyimide film (100 mol%). On the other hand, the content of the biphenyltetracarboxylic dianehydride in the second block may be 25 mol% or less, based on the total content of the dianhydride acid component of the polyimide film, which is 100 mol%.

[0043] Furthermore, the m-tolidine content of the third block of the block copolymer may be 10 mol% or more and 35 mol% or less, based on the total content of the diamine components of the polyimide film, which is 100 mol%. The polyimide precursor composition of the present invention may contain the block copolymer (polyamic acid) and an organic solvent. The organic solvent is not particularly limited, and any solvent that can dissolve the block copolymer (polyamic acid) can be used, but an amide solvent is preferred.

[0044] Specifically, the organic solvent may be a polar organic solvent, and more specifically, it may be an aprotic polar solvent, or it may be one or more selected from the group consisting of, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone (NMP), gamma-butyrolactone (GBL), and diglyme, but is not limited thereto, and can be used individually or in combination of two or more as needed. In one example, the solvent can be N,N-dimethylformamide or N,N-dimethylacetamide, which are particularly preferred.

[0045] On the other hand, the block copolymer (polyamic acid) is present in an amount of about 5% to about 35% by weight (for example, about 5% by weight, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, or about 35% by weight) based on the total weight of the polyimide precursor composition. Within this range, the polyimide precursor composition can have a molecular weight and solution viscosity suitable for forming a film and can have excellent storage stability. Based on the total weight of the polyimide precursor composition, the block copolymer (polyamic acid) is present in an amount of about 10% to about 30% by weight, as an example, and about 15% to 20% by weight, as an other example. Furthermore, the polyimide precursor composition was heated at 23°C for 1 second. -1 It can have a viscosity of approximately 100,000 cP to approximately 300,000 cP (for example, approximately 100,000 cP, approximately 150,000 cP, approximately 200,000 cP, approximately 250,000 cP, or approximately 300,000 cP) at a shear rate.

[0046] Within the aforementioned range, the block copolymer (polyamic acid) can have a predetermined weight-average molecular weight while exhibiting excellent processability during the film formation of the polyimide film. Here, "viscosity" can be measured using a HAAKE Mars Rheometer. The polyimide precursor composition was heated at 23°C for 1 second.-1 At shear rates, the viscosity can be, for example, approximately 150,000 cP to approximately 250,000 cP, and in other examples, approximately 200,000 cP to approximately 250,000 cP, but is not limited to these values. The aforementioned block copolymer (polyamic acid) may have a weight-average molecular weight (Mw) of approximately 100,000 g / mol or more, for example, approximately 100,000 g / mol to approximately 500,000 g / mol, and within this range may be advantageous for the production of superior polyimide coated films or movies, but is not limited thereto. Here, the "weight-average molecular weight" can be measured using gel permeation chromatography (GPC).

[0047] The polyimide precursor composition of the present invention may be provided as a varnish and used to manufacture polyimide coated films, or it may be used to manufacture the polyimide film of the present invention. To obtain a polyimide coated film, a polyimide precursor composition can be applied to a substrate by conventional known methods such as spin coating, spray coating, screen printing, immersion, curtain coating, dip coating, or die coating, dried at a temperature of 250°C or lower to remove the solvent, and then imidized.

[0048] The polyimide precursor composition of the present invention may contain other components, as long as they do not hinder the objectives of the present invention. Examples of other components include base generating agents, polymerizable components such as monomers, surfactants, plasticizers, viscosity modifiers, defoamers, colorants, and fillers. The filler material is not particularly limited, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica. A method for producing a polyimide precursor composition according to the present invention may include the steps of: (a) polymerizing biphenyltetracarboxylic dianehydride and paraphenylenediamine in an organic solvent to produce a first polyamic acid containing a first block of a block copolymer; (b) polymerizing biphenyltetracarboxylic dianehydride and m-tolidine to the first polyamic acid formed in step (a) to produce a second polyamic acid containing the first and second blocks of the block copolymer; and (c) polymerizing pyromeretic dianehydride and m-tolidine to the second polyamic acid formed in step (b) to produce a third polyamic acid containing the first, second, and third blocks of the block copolymer.

[0049] In one embodiment, based on a total content of 100 mol% of the diamine components of the block copolymer, the content of m-tolidine may be 25 mol% or more and 40 mol% or less, and the content of paraphenylenediamine may be 60 mol% or more and 75 mol% or less. Based on a total content of 100 mol% of the dianhydric acid components of the block copolymer, the content of biphenyltetracarboxylic dianehydride may be 50 mol% or more and 65 mol% or less, and the content of pyromeretic dianehydride may be 35 mol% or more and 50 mol% or less. In one embodiment, the content of the biphenyltetracarboxylic dianehydride in the first block of the block copolymer is 40 mol% or more and 55 mol% or less, based on the total content of the dianhydride acid component of the block copolymer (100 mol%), and the content of the biphenyltetracarboxylic dianehydride in the second block is The total content of the dianhydride acid component in the polyimide film may be 10 mol% or more, based on 100 mol%.

[0050] On the other hand, the content of the biphenyltetracarboxylic dianehydride in the second block may be 25 mol% or less, based on the total content of the dianhydride acid component of the polyimide film, which is 100 mol%. Furthermore, the m-tolidine content of the third block of the block copolymer may be 10 mol% or more and 35 mol% or less, based on the total content of the diamine components of the polyimide film, which is 100 mol%. [Examples]

[0051] The operation and effects of the invention will be described in more detail below through specific embodiments of the invention. However, these embodiments are merely presented as examples of the invention and do not define the scope of the invention's rights.

[0052] <Manufacturing example> NMP was added to a 500 ml reactor equipped with a stirrer and nitrogen injection / discharge pipes while nitrogen was injected. After setting the reactor temperature to 30°C, paraphenylenediamine and m-tolidine were added as diamine components, and biphenyltetracarboxylic dianehydride and pyromeretic dianehydride were added as dianhydric acid components in the specified order. Block copolymerization was carried out by heating to 40°C under a nitrogen atmosphere and stirring for 120 minutes, producing a polyamic acid exhibiting a viscosity of 200,000 cP at 23°C. The manufactured polyamic acid was degassed by high-speed rotation of 1,500 rpm or more to remove air bubbles. Thereafter, the degassed polyimide precursor composition was coated onto a glass substrate using a spin coater. Subsequently, a gel film was produced by drying under a nitrogen atmosphere at a temperature of 120°C for 30 minutes. The gel film was then heated to 450°C at a rate of 2°C / min, heat-treated at 450°C for 60 minutes, and cooled to 30°C at a rate of 2°C / min to obtain a polyimide film.

[0053] Subsequently, the polyimide film was peeled off the glass substrate by dipping it in distilled water. The thickness of the manufactured polyimide film was 15 μm. The thickness of the manufactured polyimide film was measured using an electric film thickness tester manufactured by Anritsu. In the following examples, the content of diamine components is expressed in mol% of each diamine component based on the total content of diamine components in the polyimide film (100 mol%), and the content of dianhydride acid components is expressed in mol% of each dianhydride acid component based on the total content of dianhydride acid components in the polyimide film (100 mol%).

[0054] <Example 1> As described above, a polyimide film was produced by copolymerizing diamine and dianhydride components in the following order: paraphenylenediamine (70 mol%), biphenyltetracarboxylic dianehydride (45 mol%), m-tolidine (15 mol%), biphenyltetracarboxylic dianehydride (15 mol%), m-tolidine (15 mol%), and pyromeretic dianehydride (40 mol%).

[0055] <Example 2> As described above, the diamine component and dianhydride acid component were added in the following order: paraphenylenediamine (70 mol%), biphenyltetracarboxylic dianehydride (50 mol%), m-tolidine (10 mol%), biphenyltetracarboxylic dianehydride (10 mol%), m-tolidine (20 mol%), and pyromeretic dianehydride (40 mol%), and copolymerized to produce a polyimide film.

[0056] <Example 3> As described above, the diamine component and dianhydride acid component were added in the following order: paraphenylenediamine (65 mol%), biphenyltetracarboxylic dianehydride (40 mol%), m-tolidine (10 mol%), biphenyltetracarboxylic dianehydride (10 mol%), m-tolidine (25 mol%), and pyromeretic dianehydride (50 mol%), and copolymerized to produce a polyimide film.

[0057] <Example 4> As described above, the diamine component and dianhydride acid component were added in the following order: paraphenylenediamine (60 mol%), biphenyltetracarboxylic dianehydride (40 mol%), m-tolidine (15 mol%), biphenyltetracarboxylic dianehydride (15 mol%), m-tolidine (25 mol%), and pyromeretic dianehydride (45 mol%), and copolymerized to produce a polyimide film.

[0058] <Example 5> As described above, a polyimide film was produced by copolymerizing diamine and dianhydride components in the following order: paraphenylenediamine (60 mol%), biphenyltetracarboxylic dianehydride (40 mol%), m-tolidine (10 mol%), biphenyltetracarboxylic dianehydride (10 mol%), m-tolidine (30 mol%), and pyromeretic dianehydride (50 mol%).

[0059] <Comparative Example 1> As described above, a polyimide film was produced by copolymerizing diamine and dianhydride components in the following order: paraphenylenediamine (55 mol%), biphenyltetracarboxylic dianehydride (50 mol%), m-tolidine (45 mol%), and pyromeretic dianehydride (50 mol%).

[0060] <Comparative Example 2> As described above, a polyimide film was produced by copolymerizing the diamine component and the dianhydride acid component in the following order: m-tolidine (80 mol%), biphenyltetracarboxylic dianehydride (40 mol%), paraphenylenediamine (20 mol%), and pyromeretic dianehydride (60 mol%).

[0061] <Comparative Example 3> As described above, a polyimide film was produced by copolymerizing the diamine component and the dianhydride acid component in the following order: m-tolidine (80 mol%), biphenyltetracarboxylic dianehydride (30 mol%), paraphenylenediamine (20 mol%), and pyromeretic dianehydride (70 mol%).

[0062] <Comparative Example 4> As described above, a polyimide film was produced by copolymerizing the diamine component and the dianhydride acid component in the following order: m-tolidine (60 mol%), biphenyltetracarboxylic dianehydride (40 mol%), paraphenylenediamine (40 mol%), and pyromeretic dianehydride (60 mol%).

[0063] <Comparative Example 5> According to the manufacturing example described above, the diamine component and dianhydride component were obtained as paraphenylenediamine (80 mol%), biphenyltetracarboxylic dianehydride (70 mol%), m-tolidine (20 mol%), and pyromeretic dianehydride (30 mol%). The materials were added in the order of %) and copolymerized to produce a polyimide film. Table 1 below shows the components and their content of the polyimide films produced in Examples 1-5 and Comparative Examples 1-5. [Table 1]

[0064] <Experimental Example> Evaluation of Dielectric Constant, Dielectric Loss, Thermal Expansion Coefficient, and Glass Transition Temperature The dielectric constant, dielectric loss rate, thermal expansion coefficient, and glass transition temperature were measured for the polyimide films produced in Examples 1 to 5 and Comparative Examples 1 to 5, respectively, and the results are shown in Table 2 below.

[0065] (1) Measurement of dielectric constant (Dk) The dielectric constant (Dk) was measured at 10 GHz using a Keysight network analyzer and a QWED SPDR resonator after drying the sample in a 130°C oven for 30 minutes and leaving it in an environment of 23°C and 50% relative humidity for 24 hours.

[0066] (2) Measurement of dielectric loss (Df) The dielectric loss (Df) was measured at 10 GHz using a Keysight network analyzer and a QWED SPDR resonator after drying the sample in a 130°C oven for 30 minutes and leaving it in an environment of 23°C and 50% relative humidity for 24 hours.

[0067] (3) Measurement of the coefficient of thermal expansion (CTE) The coefficient of thermal expansion (CTE) was determined using a TA Corporation Q400 thermomechanical analyzer. A polyimide film was cut into 4mm wide and 20mm long pieces. Under a nitrogen atmosphere, a tension of 0.05N was applied, and the temperature was raised from room temperature to 300°C at a rate of 10°C / min. The temperature was then cooled again at a rate of 10°C / min, and the gradient in the range from 100°C to 200°C was measured.

[0068] (4) Measurement of glass transition temperature Glass transition temperature (T g The loss modulus and storage modulus of each film were determined using DMA, and the inflection points in their tangent graphs were measured as the glass transition temperature. [Table 2]

[0069] As shown in Table 2 above, the polyimide film produced by the embodiment of the present invention not only exhibits an extremely low dielectric loss rate of 0.003 or less, but also demonstrates that the coefficient of thermal expansion and glass transition temperature are at desired levels. These results are achieved by the components and compositional ratios specified in this application, demonstrating that the content of each component plays a decisive role. In contrast, the polyimide films of Comparative Examples 1 to 5, which have different components from Examples 1 to 5, can be expected to be difficult to use in electronic components where signals are transmitted at gigabit-high frequencies in terms of dielectric loss rate, thermal expansion coefficient, and glass transition temperature, or in one or more of these aspects. As described above with reference to embodiments of the present invention, a person with ordinary skill in the art to which the present invention belongs will be able to make various applications and modifications within the scope of the present invention based on the above content. [Industrial applicability]

[0070] As described above, the present invention provides a polyimide film having excellent high heat resistance, low dielectric properties, and dimensional stability properties by comprising a polyimide film consisting of specific components and a specific composition ratio, and a polyamide precursor composition for producing the same. As such properties are usefully applicable to a variety of fields where they are required, particularly to electronic components such as flexible metal foil laminates.

Claims

1. A first block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing biphenyltetracarboxylic dianehydride (BPDA) and a diamine component containing paraphenylenediamine (PPD), A second block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride component containing biphenyltetracarboxylic dianehydride and a diamine component containing m-tolidine, The material comprises a block copolymer containing a third block obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component containing pyromeretic dianehydride (PMDA) and a diamine component containing m-tolidine, Based on a total diamine content of 100 mol% in the polyimide film, the content of m-tolidine is 25 mol% or more and 40 mol% or less, and the content of paraphenylenediamine is 60 mol% or more and 75 mol% or less. Based on a total content of 100 mol% of dianhydride components in the polyimide film, the content of biphenyltetracarboxylic dianehydride is 50 mol% or more and 65 mol% or less. The pyromeretic dianehydride content is 35 mol% or more and 50 mol% or less, and the biphenyltetracarboxylic dianehydride content of the first block is 40 mol% or more and 55 mol% or less, based on the total content of dianhydride acid components of the polyimide film, which is 100 mol%. The content of the biphenyltetracarboxylic dianehydride in the second block is 10 mol% or more, based on the total content of the dianhydride acid component in the polyimide film, The m-tolidine content of the third block is 10 mol% or more and 35 mol% or less, based on the total content of the diamine components of the polyimide film, which is 100 mol%. Polyimide film.

2. The aforementioned polyimide film was obtained by imidizing a polyamic acid derived from a polymer of a dianhydride acid component consisting of biphenyltetracarboxylic dianehydride and pyromeretic dianehydride, and a diamine component consisting of paraphenylenediamine and m-tolidine. The polyimide film according to claim 1.

3. The dielectric loss ratio (Df) is 0.003 or less. The coefficient of thermal expansion (CTE) is 13 ppm / °C or higher and 23 ppm / °C or lower. The glass transition temperature (Tg) is 320°C or higher. The polyimide film according to claim 1.

4. A multilayer film comprising a polyimide film according to any one of claims 1 to 3 and a thermoplastic resin layer.

5. A polyimide film according to any one of claims 1 to 3, and an electrically conductive metal foil, Flexible metal foil laminate.

6. Including the flexible metal foil laminate described in claim 5, Electronic components.

7. A first block obtained by reacting a dianhydride acid component containing biphenyltetracarboxylic dianehydride (BPDA) with a diamine component containing paraphenylenediamine (PPD), A second block obtained by reacting a dianhydride acid component containing biphenyltetracarboxylic dianehydride with a diamine component containing m-tolidine, The material comprises a block copolymer containing a third block obtained by reacting a dianhydride acid component containing pyromeretic dianehydride (PMDA) with a diamine component containing m-tolidine, Based on a total diamine content of 100 mol% in the polyimide film, the content of m-tolidine is 25 mol% or more and 40 mol% or less, and the content of paraphenylenediamine is 60 mol% or more and 75 mol% or less. Based on a total content of 100 mol% of dianhydride components in the polyimide film, the content of biphenyltetracarboxylic dianehydride is 50 mol% or more and 65 mol% or less. The pyromeretic dianehydride content is 35 mol% or more and 50 mol% or less, and the biphenyltetracarboxylic dianehydride content of the first block is 40 mol% or more and 55 mol% or less, based on the total content of dianhydride acid components of the polyimide film, which is 100 mol%. The content of the biphenyltetracarboxylic dianehydride in the second block is 10 mol% or more, based on the total content of the dianhydride acid component in the polyimide film, The m-tolidine content of the third block is 10 mol% or more and 35 mol% or less, based on the total content of the diamine components of the polyimide film, which is 100 mol%. Polyimide precursor composition.

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