TW202417546A - Polyimide film, flexible metal foil clad laminate and electronic component comprising the same - Google Patents

Abstract

The present invention provides a polyimide film having a yield strength of 138 MPa or more, a glass transition temperature of 370°C or more, excellent heat resistance and mechanical properties, and a method for producing the same.

Description

Polyimide film, flexible metal-clad foil laminate and electronic component thereof

The present invention relates to a polyimide film having excellent heat resistance and mechanical properties (yield strength and yield point) and a method for producing the same.

Polyimide (PI) is based on a rigid aromatic main chain and an imide ring with excellent chemical stability. It is a polymer material that has the highest level of heat resistance, chemical resistance, electrical insulation, chemical resistance, and weather resistance among organic materials.

Polyimide films have attracted much attention as materials for various electronic devices requiring the above-mentioned properties.

Microelectronic components using polyimide films can be, for example, flexible ultra-thin circuit substrates with high circuit integration, so as to cope with the lightweight and miniaturization of electronic products. Polyimide films are particularly widely used as insulating films for ultra-thin circuit substrates.

The structure of the aforementioned ultra-thin circuit substrate is generally that a circuit including a metal foil is formed on an insulating film. In a broad sense, such an ultra-thin circuit substrate is called a flexible metal foil clad laminate (Flexible Metal Foil Clad Laminate). When a thin copper plate is used as the metal foil, in a narrow sense, it is also called a flexible copper clad laminate (Flexible Copper Clad Laminate: FCCL).

As a method for manufacturing a flexible metal-clad laminate, for example: (i) a casting method in which polyamide as a polyimide precursor is cast or coated on a metal foil and then imidized; (ii) a metallization method in which a metal layer is directly provided on a polyimide film by sputtering; and (iii) a lamination method in which a polyimide film and a metal foil are bonded by heat and pressure using thermoplastic polyimide.

In particular, the metallization method, for example, sputtering a metal such as copper on a polyimide film with a thickness of 20 μm to 38 μm and depositing a tie layer and a seed layer in sequence to produce a flexible metal-clad laminate, has advantages in forming ultra-fine circuits with a pitch of less than 35 μm in the circuit pattern, and is widely used to manufacture flexible metal-clad laminates for COF (chip on film).

The polyimide film used in this flexible metal-clad laminate needs to have high heat resistance and mechanical properties, and thus there is an urgent need for a polyimide film that can have both excellent heat resistance and mechanical properties.

The matters described in the above prior art are used to help understanding the background of the invention and may include matters of the prior art that are not known to ordinary technicians in the technical field.

[Prior Art Documents] [Patent Documents] Patent Document 1: Korean Granted Patent No. 10-1375276. Patent Document 2: Korean Publication Patent Gazette No. 2016-0002402.

[Technical topics]

Therefore, an object of the present invention is to provide a polyimide film having excellent heat resistance and mechanical properties (yield strength and yield point) and a method for producing the same.

However, the issues to be solved by the present invention are not limited to the issues mentioned above, and other issues not mentioned can be clearly understood by practitioners from the following description. [Technical Solution]

In order to achieve the above-mentioned object, one aspect of the present invention provides a flexible metal-clad laminate having a yield strength of 138 MPa or more and a glass transition temperature of 370°C or more.

Another aspect of the present invention provides a flexible metal-clad laminate comprising the aforementioned polyimide film and a conductive metal foil.

Another aspect of the present invention provides an electronic component including the aforementioned flexible metal-clad foil laminate. [Effect of the invention]

The present invention provides a polyimide film having excellent heat resistance, yield point and yield strength characteristics by providing a polyimide film in which the ratio and reaction ratio of dianhydride and diamine components are adjusted, thereby improving the processing performance of the polyimide film.

This polyimide film can be applied to various fields requiring a polyimide film with excellent characteristics, for example, it can be applied to a flexible metal-clad laminated plate manufactured according to a metallization method or an electronic component including this flexible metal-clad laminated plate.

The terms or words used in this specification and the scope of the patent application shall not be interpreted in a limited manner to the usual or dictionary meanings, but shall be based on the principle that "the inventor can appropriately define the concept of the term in order to explain his own invention in the best way" and shall only be interpreted as the meaning and concept that conforms to the technical idea of the present invention.

Therefore, the embodiments described in this specification are merely the best embodiments of the present invention and do not fully represent the technical ideas of the present invention. Therefore, it should be understood that there will be various equivalents and modifications that can replace them at the time of this application.

Unless the context clearly indicates otherwise, singular expressions in this specification include plural expressions. In this specification, terms such as "including", "having" or "having" are intended to specify the existence of features, numbers, steps, constituent elements or combinations thereof of the implementation, and should be understood as not excluding the existence or additional possibility of one or more other features or numbers, steps, constituent elements or combinations thereof in advance.

In this specification, "dianhydride" is meant to include precursors or derivatives thereof which may not technically be dianhydrides but nevertheless react with diamines to form polyamides which can in turn be converted into polyimines.

In this specification, "diamine" is meant to include precursors or derivatives thereof which may not technically be diamines but nevertheless react with dianhydrides to form polyamides which can in turn be converted into polyimines.

In this specification, when an amount, concentration or other value or parameter is given by listing a range, a preferred range or a preferred upper limit and a preferred lower limit, it should be understood that all ranges formed by any pair of any range upper limit or preferred value and any range lower limit or preferred value are specifically disclosed, regardless of whether the range is disclosed separately.

When a range of numerical values is mentioned in this specification, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within the range. The scope of the present invention is not intended to be limited to the specific values mentioned when defining the range.

In this specification, in "a to b" and "a~b" indicating a numerical range, "to" and "~" are defined as ≥a and ≤b.

The polyimide film of an embodiment of the present invention may have a yield strength of 138 MPa or more and a glass transition temperature of 370° C. or more.

On the other hand, the polyimide film may have a yield strength of 150 MPa or less and a glass transition temperature of 380° C. or less.

For example, the yield strength of the polyimide film may be 138 MPa or more, 140 MPa or more, or 145 MPa or more.

In one implementation example, the yield point of the polyimide film may be greater than 2.4%.

On the other hand, the yield point of the polyimide film may be 2.6% or less.

In one embodiment, the polyimide film can be obtained by subjecting a polyimide solution containing a dianhydride component and a diamine component to an imidization reaction, wherein the dianhydride component includes biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA), and the diamine component includes p-phenylenediamine (PPD), m-tolidine and diaminodiphenyl ether (ODA).

That is, the polyimide film can be obtained by imidizing a polyamide derived from a polymer composed of biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, p-phenylenediamine, m-tolidine and diaminodiphenyl ether.

In one implementation example, based on the total content of the aforementioned dianhydride components being 100 mol %, the content of the aforementioned biphenyltetracarboxylic dianhydride may be greater than 15 mol % and less than 30 mol %, the content of the aforementioned pyromellitic dianhydride may be greater than 30 mol % and less than 50 mol %, and the content of the aforementioned benzophenone tetracarboxylic dianhydride may be greater than 25 mol % and less than 45 mol %.

For example, based on 100 mol % of the total content of the dianhydride components, the content of the biphenyltetracarboxylic dianhydride may be greater than 20 mol % and less than 25 mol %, the content of the pyromellitic dianhydride may be greater than 35 mol % and less than 45 mol %, and the content of the benzophenone tetracarboxylic dianhydride may be greater than 30 mol % and less than 45 mol %.

In one embodiment, based on the total content of the aforementioned diamine components being 100 mol %, the content of the aforementioned p-phenylenediamine may be greater than 45 mol % and less than 60 mol %, the content of the aforementioned m-tolidine may be greater than 10 mol % and less than 25 mol %, and the content of the aforementioned diaminodiphenyl ether may be greater than 20 mol % and less than 40 mol %.

For example, based on 100 mol % of the total content of the aforementioned diamine components, the content of the aforementioned p-phenylenediamine can be greater than 50 mol % and less than 60 mol %, the content of the aforementioned m-tolidine can be greater than 10 mol % and less than 15 mol %, and the content of the aforementioned diaminodiphenyl ether can be greater than 25 mol % and less than 35 mol %.

The p-phenylenediamine of the present invention is a rigid monomer. With the increase of the p-phenylenediamine content, the synthesized polyimide has a more linear structure, which helps to improve the mechanical properties and heat resistance of the polyimide.

In addition, meta-tolidine particularly contains a benzene ring structure having a methyl group, which can contribute to improving the mechanical properties and heat resistance of the polyimide film.

The polyimide chain derived from biphenyltetracarboxylic dianhydride of the present invention has a structure named as a charge transfer complex (CTC), that is, a regular linear structure in which electron donors and electron acceptors are arranged close to each other, which strengthens the intermolecular interaction and affects the heat resistance and mechanical properties of the polyimide film.

In addition, pyromellitic dianhydride is a dianhydride component with a relatively rigid structure and can impart appropriate elasticity to the polyimide film.

In order for polyimide film to have excellent mechanical properties and heat resistance, the content ratio of dianhydride is very important. For example, the lower the content ratio of biphenyltetracarboxylic dianhydride, the lower the mechanical properties and heat resistance caused by the aforementioned CTC structure.

In addition, biphenyltetracarboxylic dianhydride and benzophenonetetracarboxylic dianhydride contain two benzene rings corresponding to the aromatic part, whereas pyromellitic dianhydride contains one benzene ring corresponding to the aromatic part.

In the dianhydride component, the increase in the content of pyromellitic dianhydride can be understood as an increase in the imide groups in the molecule when the molecular weight is the same. This can be understood as the ratio of the imide groups derived from the aforementioned pyromellitic dianhydride to the imide groups derived from biphenyltetracarboxylic dianhydride and dibenzophenonetetracarboxylic dianhydride in the polyimide polymer chain is relatively increased.

That is, an excessive increase in the content of pyromellitic dianhydride can be regarded as a relative increase in imide groups even with respect to the entire polyimide film, so it is difficult to expect improvements in mechanical properties and heat resistance.

On the contrary, if the content of pyromellitic dianhydride is excessively reduced, the rigid structural component is relatively reduced and the elasticity of the polyimide film will drop below the desired level.

For this reason, when the content of the biphenyltetracarboxylic dianhydride exceeds the above range or the content of the pyromellitic dianhydride is below the above range, the mechanical properties and heat resistance of the polyimide film are reduced.

On the contrary, when the content of the biphenyltetracarboxylic dianhydride is lower than the above range or the content of the pyromellitic dianhydride exceeds the above range, it will also have an adverse effect on the mechanical properties and heat resistance of the polyimide film.

Therefore, if the content ranges of biphenyltetracarboxylic dianhydride, isomellitic dianhydride and dibenzophenone tetracarboxylic dianhydride as dianhydride components and the content ranges of p-phenylenediamine, m-toluidine and diaminodiphenyl ether as diamine components of the polyimide film of the present case are higher or lower than the content ranges of the present case, the heat resistance (glass transition temperature) and/or mechanical properties (yield point, yield strength) will be reduced.

In one implementation example, the polyimide of the polyimide film may be a block copolymer including a first block, wherein the first block is obtained by subjecting a dianhydride component including the biphenyltetracarboxylic dianhydride to an imidization reaction with a diamine component including the meta-tolidine.

That is, the polyimide may be a block copolymer including two or more blocks.

On the other hand, the first block can be obtained by imidizing a polyamide derived from a polymer of a dianhydride component consisting of biphenyltetracarboxylic dianhydride and a diamine component consisting of m-tolidine.

In one implementation example, based on 100 mol % of the total content of the polyimide, the content of the first block may be greater than 10 mol % and less than 16 mol %.

If the content of the first block is lower than the range of the present invention, the glass transition temperature of the polyimide film is lowered and the heat resistance is reduced. In addition, if the content of the first block exceeds the range of the present invention, the yield point and/or yield strength of the polyimide film is reduced.

In the present invention, the production of polyamine acid can be carried out by the following methods, for example: (1) A method of adding the entire amount of the diamine component to a solvent, and then adding the dianhydride component so that the diamine component and the dianhydride component are substantially equimolar and polymerizing; (2) A method of adding the entire amount of the dianhydride component to a solvent, and then adding the diamine component so that the diamine component and the dianhydride component are substantially equimolar and polymerizing; (3) A method of adding a portion of the diamine component to a solvent, mixing a portion of the dianhydride component at a ratio of about 95 to 105 mol% relative to the reaction component, adding the remaining diamine component, and then adding the remaining dianhydride component so that the diamine component and the dianhydride component are substantially equimolar and polymerizing; (4) Method, after adding the dianhydride component to the solvent, relative to the reaction component, a portion of the diamine compound is mixed at a ratio of 95-105 mol%, and then the other dianhydride components are added, and then the remaining diamine components are added, so that the diamine component and the dianhydride component are substantially equal in molar ratio and then polymerized; (5) A method comprising reacting a portion of a diamine component with a portion of a dianhydride component in a solvent so that one of them is excessive to form a first composition, reacting a portion of a diamine component with a portion of a dianhydride component in another solvent so that one of them is excessive to form a second composition, mixing the first and second compositions and completing polymerization. At this time, if the diamine component is excessive when forming the first composition, the dianhydride component is excessive in the second composition, and if the dianhydride component is excessive in the first composition, the diamine component is excessive in the second composition. The first and second compositions are mixed so that the total diamine component and dianhydride component used in these reactions are substantially equimolar, and then polymerization is performed.

In the present invention, the polymerization method of polyamic acid as described above can be defined as a random polymerization method, and the polyimide film produced from polyamic acid of the present invention produced by the above process can be preferably applied in maximizing the effect of the present invention.

However, the aforementioned polymerization method has limitations in terms of exerting the various excellent properties of the polyimide chain derived from the dianhydride component because the length of the repeating unit in the polymer chain described above is relatively short. Therefore, the polymerization method of polyamide acid that can be particularly preferably utilized in the present invention can be a block polymerization method.

In a specific example, the method for manufacturing the polyimide film of the present invention may include:

The invention further comprises a step of polymerizing biphenyltetracarboxylic dianhydride and meta-tolidine in an organic solvent to prepare a polyamide comprising a first block of a block copolymer.

In addition, the method for producing the polyimide film may include: in addition to the biphenyltetracarboxylic dianhydride and meta-tolidine forming the first block, the remaining dianhydride components and diamine components are combined to produce a polyamide containing an additional block required to embody the characteristics of the polyimide film in addition to the first block.

On the other hand, the polyamine comprising the first block of the block copolymer can be prepared before the polyamine comprising other blocks, or the polyamine comprising other blocks can be prepared first and then the polyamine comprising the first block.

For example, after biphenyltetracarboxylic dianhydride and meta-tolidine are added together to produce a polyamide containing a first block, a dianhydride component and a diamine component that form the remaining blocks are further added to the polyamide containing the produced first block in a predetermined order and imidized to produce a polyimide as a block copolymer.

In addition, after first manufacturing a polyamide containing a block other than the first block, or during the manufacturing of the polyamide containing a block other than the first block, biphenyltetracarboxylic dianhydride and meta-tolidine can be added to the manufactured polyamide containing a block other than the first block to manufacture the polyamide containing the first block.

On the other hand, the solvent used for synthesizing polyamine is not particularly limited, and any solvent can be used as long as it can dissolve polyamine, but an amide solvent is preferred.

Specifically, the aforementioned solvent may be an organic polar solvent, more specifically, an aprotic polar solvent, for example, one or more selected from the group consisting of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone (NMP), γ-butyrolactone (GBL), and diglyme (Diglyme), but is not limited thereto and may be used alone or in combination of two or more as needed.

In one example, the aforementioned solvent may preferably include N,N-dimethylformamide and N,N-dimethylacetamide.

In addition, during the polyamide manufacturing process, fillers may be added to improve various properties of the film, such as slip, thermal conductivity, corona resistance, and ring hardness. The added fillers are not particularly limited, and preferred examples include silicon dioxide, titanium oxide, aluminum oxide, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, and mica.

The particle size of the filler is not particularly limited and can be determined according to the film properties to be improved and the type of filler added. Generally speaking, the average particle size is 0.05 μm to 100 μm, preferably 0.1 μm to 75 μm, more preferably 0.1 μm to 50 μm, and particularly preferably 0.1 μm to 25 μm.

If the particle size is below this range, the modification effect is difficult to show, and if it exceeds this range, the surface properties may be greatly damaged or the mechanical properties may be greatly reduced.

In addition, the amount of filler added is not particularly limited and can be determined according to the film properties to be improved or the filler particle size, etc. Generally speaking, the amount of filler 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, relative to 100 parts by weight of polyimide.

If the amount of filler added is below this range, the improvement effect of the filler is difficult to show, and if it exceeds this range, there is a possibility that the mechanical properties of the film will be greatly damaged. The method of adding the filler is not particularly limited, and any known method can be used.

In the manufacturing method of the present invention, the polyimide film can be manufactured according to the thermal imidization method and the chemical imidization method.

Alternatively, it can be produced by a combined imidization method using a thermal imidization method and a chemical imidization method.

The so-called thermal imidization method is a method that uses a heat source such as hot air or an infrared dryer to induce the imidization reaction without using a chemical catalyst.

The aforementioned thermal imidization method can heat-treat the aforementioned gel film at a variable temperature in the range of 100 to 600°C to imidize the amide groups present in the gel film. Specifically, the heat treatment can be performed at 200 to 500°C, and more specifically, at 300 to 500°C to imidize the amide groups present in the gel film.

However, during the process of forming the gel film, a portion of the polyamine (about 0.1 mol% to 10 mol%) will be imidized. For this purpose, the polyamine composition can be dried at a variable temperature in the range of 50°C to 200°C, which can also be included in the scope of the aforementioned thermal imidization method.

In the chemical imidization method, a polyimide membrane can be produced using a dehydrating agent and an imidizing agent according to a method known in the industry.

As an example of the composite imidization method, a dehydrating agent and an imidizing agent may be added to a polyamide solution, and then heated at 80 to 200°C, preferably 100 to 180°C. After partial curing and drying, the solution may be heated at 200 to 400°C for 5 to 400 seconds to produce a polyimide film.

The present invention provides a multilayer film including the above-mentioned polyimide film.

The aforementioned multi-layer film may include a supplementary polyimide film such as a thermoplastic polyimide film.

The present invention provides a flexible metal-clad laminate comprising the polyimide film and a conductive metal foil.

The metal foil used is not particularly limited, but when the flexible metal foil laminate of the present invention is used for electronic components or electronic equipment, for example, it can be a metal foil including copper or copper alloys, stainless steel or its alloys, nickel or nickel alloys (including 42 alloys), aluminum or aluminum alloys.

In common flexible metal foil laminated plates, copper foils called rolled copper foils and electrolytic copper foils are widely used, and can also be preferably used in the present invention. In addition, the surfaces of these metal foils can also be coated with a rust-proof layer, a heat-resistant layer or an adhesive layer.

In the present invention, the thickness of the metal foil is not particularly limited as long as it is a thickness that can fully exert its function according to its application.

The flexible metal foil-clad laminated plate of the present invention may be a structure in which a metal foil is laminated on at least one side of the polyimide film.

The following is a more detailed description of the functions and effects of the invention through specific manufacturing examples and embodiments of the invention. However, such manufacturing examples and embodiments are only provided as examples of the invention, and the scope of the invention is not limited thereby. [ Manufacturing Example: Manufacturing of Polyimide Film ]

The polyimide film of the present invention can be produced by the following common method known in the industry: First, the dianhydride and the diamine component are reacted in an organic solvent to obtain a polyimide solution.

At this time, the solvent is generally an amide solvent, and an aprotic polar solvent (Aprotic solvent) can be used, for example, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone or a combination thereof can be used.

The dianhydride and diamine components can be added in the form of powder, agglomerate or solution. In the initial stage of the reaction, they are added in the form of powder. After the reaction, in order to adjust the polymerization viscosity, they are preferably added in the form of solution.

The obtained polyamine solution can be mixed with an imidization catalyst and a dehydrating agent and coated on a support.

Examples of the catalyst used include tertiary amines (e.g., isoquinoline, β-picoline, pyridine, etc.), and examples of the dehydrating agent include acid anhydrides, but are not limited to these. In addition, the support used above may include, for example, a glass plate, an aluminum foil, a circulating stainless steel belt, or a stainless steel drum, but are not limited to these.

The film coated on the aforementioned support is gelled on the support by dry air and heat treatment.

The gelled film is separated from the support and heat treated to achieve drying and imidization.

The film that has completed the above heat treatment can be heat treated under a predetermined tension to remove the residual stress inside the film that occurs during the film forming process.

Specifically, 500 ml of DMF was added while nitrogen was injected into a reactor equipped with a stirrer and a nitrogen injection/exhaust pipe, and after the temperature of the reactor was set to 25°C, biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), benzophenonetetracarboxylic dianhydride (BTDA), p-phenylenediamine (PPD), m-tolidine, diaminodiphenyl ether (ODA) and 4,4'-diaminobenzanilide (4,4'-diaminobenzanilide) were added in the adjusted composition and determined order and completely dissolved.

During the addition, biphenyltetracarboxylic dianhydride and m-tolidine may be added continuously to allow the dianhydride component containing biphenyltetracarboxylic dianhydride and the diamine component containing m-tolidine to undergo an imidization reaction to obtain the first block.

Then, under a nitrogen atmosphere, the temperature of the reactor was raised to 30°C and stirred for 120 minutes while heating, producing polyamine with a primary reaction viscosity of 800~1,200 cP.

The polyamide thus produced is stirred so as to finally reach a viscosity of 40,000~160,000 cP.

After adjusting the content of the catalyst and the dehydrating agent and adding them to the prepared final polyimide, a polyimide film was manufactured using a coater. [ Example and Comparative Example ]

As shown in Table 1 below, the contents of the dianhydride component and the aforementioned diamine component in Examples 1 to 4 and Comparative Examples 1 to 5 were adjusted, and polyimide films were manufactured according to the manufacturing examples.

In addition, by adjusting the order and amount of the dianhydride component and the aforementioned diamine component, although the polyimide films of Examples 1 to 4 and Comparative Examples 1 to 3 include the first block obtained by the imidization reaction of the dianhydride component containing biphenyltetracarboxylic acid dianhydride and the diamine component containing meta-tolidine, the polyimide films of Comparative Examples 4 and 5 do not include the first block obtained by the imidization reaction of the dianhydride component containing biphenyltetracarboxylic acid dianhydride and the diamine component containing meta-tolidine.

In addition, the content of the first block obtained by allowing the dianhydride component containing biphenyltetracarboxylic dianhydride and the diamine component containing meta-tolidine to undergo an amide reaction in the polyimide films of Comparative Examples 1 to 3 is greater than 5 mol% and less than 8 mol%, based on the total content of the aforementioned polyimide film of 100 mol%.

On the other hand, the content of the first block obtained by imidization reaction of the dianhydride component containing biphenyltetracarboxylic dianhydride and the diamine component containing meta-tolidine in the polyimide films of Examples 1 to 4 is 10 mol% or more and 16 mol% or less based on 100 mol% of the total content of the polyimide film. [Table 1] Dianhydride Diamine PMDA BPDA BTDA ODA PPD m-Tolidine 4,4'-DABA Embodiment 1 40 20 40 30 58 12 - Embodiment 2 40 25 35 30 58 12 - Embodiment 3 40 twenty three 37 34 54 12 - Embodiment 4 40 20 40 34 56 10 - Comparison Example 1 40 20 40 42 53 5 - Comparison Example 2 42 20 38 45 50 5 - Comparison Example 3 40 20 40 34 58 8 - Comparison Example 4 40 20 40 34 50 8 8 Comparison Example 5 40 20 40 37 50 5 8

The glass transition temperature (Tg), yield point and yield strength of the manufactured polyimide film were measured and are shown in Table 2 below. [Table 2] Physical properties Tg(℃) Yield point (%) Yield strength (MPa) Embodiment 1 370 2.53 140.4 Embodiment 2 373 2.48 145.1 Embodiment 3 370 2.46 138.2 Embodiment 4 371 2.43 141.2 Comparison Example 1 365 2.47 114.8 Comparison Example 2 364 2.70 142.7 Comparison Example 3 369 2.54 138.7 Comparison Example 4 358 2.72 152.8 Comparison Example 5 353 2.86 149.1 (1) Measurement of glass transition temperature

The glass transition temperature (T _g ) in Table 2 above was used to determine the loss modulus and storage modulus of each film using DMA, and the inflection point in the tangent graph was measured as the glass transition temperature. (2) Measurement of yield strength at yield point

The yield point and yield strength in Table 2 above were measured by cutting the polyimide film into 15 mm × 50 mm specimens and setting the tensile speed to 200 mm/min at room temperature using a tensile tester (Instron 5564, Instron Corporation) according to ASTM D 882.

The measurement results show that the polyimide films of Examples 1 to 4 have a glass transition temperature of 370° C. or higher, a yield point of 2.4% or higher, and a yield strength of 138 MPa or higher.

By comparing the polyimide films of Examples 1 and 2 having the same content of diamine components and different contents of dianhydride components, it can be confirmed that as the content of BPDA increases and the content of BTDA decreases, the glass transition temperature of the polyimide film increases slightly, the yield point decreases slightly, and the yield strength increases slightly.

By comparing the polyimide films of Example 1 and Example 3, it can be confirmed that the yield point and yield strength of the polyimide film are slightly reduced as the content of BPDA and ODA increases and the content of PPD and BTDA decreases.

In addition, by comparing Examples 1 and 4 in which the content of the dianhydride component is the same but the content of the diamine component is different, it can be confirmed that as the content of ODA increases and the contents of PPD and meta-tolidine decrease, the glass transition temperature increases slightly, the yield point decreases slightly, and the yield strength increases slightly.

On the other hand, compared with the polyimide film of Example 1, the glass transition temperature of the polyimide film of Comparative Example 1 in which the content of ODA was increased and the contents of PPD and m-tolidine were reduced was less than 370° C., and the yield strength was also low, less than 138 MPa.

In addition, compared with the polyimide film of Example 1, the glass transition temperature of the polyimide film of Comparative Example 3 in which the content of ODA was increased and the content of m-tolidine was reduced was less than 370°C.

Compared with the polyimide film of Comparative Example 1, the yield point and yield strength of the polyimide film of Comparative Example 2, in which the contents of PMDA and ODA are further increased and the contents of BTDA and PPD are further reduced, are improved, but the glass transition temperature is still less than 370°C.

Compared with the polyimide film of Comparative Example 3, the glass transition temperature, yield point and yield strength of the polyimide film of Comparative Example 1 are all improved, but the glass transition temperature is still less than 370°C.

Comparative Examples 4 and 5, which contain 4,4'-DABA and do not contain a block obtained by an imidization reaction of a dianhydride component containing biphenyltetracarboxylic dianhydride and a diamine component containing meta-tolidine, have polyimide films having a lower glass transition temperature (less than 370°C) than the polyimide films of Examples 1 and 4 having the same dianhydride component.

Therefore, it can be confirmed that the polyimide films of Examples 1 to 4 manufactured within the appropriate range of the present case have excellent heat resistance (glass transition temperature) and mechanical properties (yield strength and yield point), but when exceeding the appropriate range of the present case, it is difficult for heat resistance and mechanical properties to coexist.

That is, it can be confirmed that the polyimide film which has heat resistance and mechanical properties and can be applied to a variety of application fields is a polyimide film produced within the appropriate range of the present case.

The embodiments of the polyimide film and the method for producing the polyimide film of the present invention are only preferred embodiments that enable ordinary skilled persons in the technical field to which the present invention belongs to easily implement the present invention, and are not limited to the aforementioned embodiments, and thus the scope of the present invention is not limited thereby. Therefore, the true technical protection scope of the present invention should be determined according to the technical idea of the accompanying patent application scope. In addition, it is self-evident for practitioners that various substitutions, deformations and changes can be realized within the scope of the technical idea of the present invention, and it is self-evident for practitioners that the parts that can be easily changed by practitioners are also included in the scope of the present invention.

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without.

Claims (9)

A polyimide film, wherein the yield strength of the polyimide film is 138 MPa or more, and the glass transition temperature is 370°C or more. The polyimide film as described in claim 1, wherein the yield point of the polyimide film is greater than 2.4%. A polyimide film as described in claim 1, wherein the polyimide film is obtained by subjecting a polyimide solution containing a dianhydride component and a diamine component to an imidization reaction, wherein the dianhydride component includes biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA), and the diamine component includes p-phenylenediamine (PPD), m-tolidine and diaminodiphenyl ether (ODA). The polyimide film as described in claim 3, wherein, based on the total content of the aforementioned dianhydride components as 100 mol%, the content of the aforementioned biphenyltetracarboxylic dianhydride is greater than 15 mol% and less than 30 mol%, the content of the aforementioned pyrophthalic dianhydride is greater than 30 mol% and less than 50 mol%, and the content of the aforementioned dibenzophenone tetracarboxylic dianhydride is greater than 25 mol% and less than 45 mol%. The polyimide film as described in claim 3, wherein, based on 100 mol % of the total content of the aforementioned diamine components, the content of the aforementioned p-phenylenediamine is greater than 45 mol % and less than 60 mol %, the content of the aforementioned m-tolidine is greater than 10 mol % and less than 25 mol %, and the content of the aforementioned diaminodiphenyl ether is greater than 20 mol % and less than 40 mol %. The polyimide film as described in claim 3, wherein the polyimide is a block copolymer including a first block, and the first block is obtained by allowing a dianhydride component including the aforementioned biphenyltetracarboxylic dianhydride and a diamine component including the aforementioned meta-tolidine to undergo an imidization reaction. The polyimide film as described in claim 6, wherein the content of the first block is greater than 10 mol % and less than 16 mol %, based on 100 mol % of the total content of the polyimide. A flexible metal-clad laminate comprising a polyimide film as described in any one of claims 1 to 7 and a conductive metal foil. An electronic component comprising the flexible metal-clad laminate as described in claim 8.