WO2021091013A1 - Polyimide film having high heat resistance and low dielectric properties, and manufacturing method for same - Google Patents

Abstract

Provided by the present invention is a polyimide film having high heat resistance and low dielectric properties comprising a block copolymer that comprises: a first block obtained by means of an imidization reaction between a dianhydride acid component comprising benzophenonetetracarboxylic dianhydride and biphenyl-tetracarboxylic dianhydride, and a diamine component comprising para-phenylenediamine; and a second block obtained by means of an imidization reaction between a dianhydride acid component comprising benzophenonetetracarboxylic dianhydride and pyromellitic dianhydride, and a diamine component comprising m-tolidine.

Description

High heat-resistant low-dielectric polyimide film and its manufacturing method

The present invention relates to a polyimide film having a high heat resistance property, a low dielectric property, and a low moisture absorption property, and a method of manufacturing the same.

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

In particular, with excellent insulating properties, that is, excellent electrical properties such as low dielectric constant, it has been in the spotlight as a high-functional polymer material in the fields of electricity, electronics, and optics.

Recently, as electronic products become lighter and smaller, thin circuit boards having high degree of integration and flexibility have been actively developed.

Such thin circuit boards tend to use a structure in which a circuit including a metal foil is formed on a polyimide film that is easily bent while having excellent heat resistance, low temperature resistance, and insulation characteristics.

As such a thin circuit board, a flexible metal clad laminate is mainly used, and an example includes a flexible copper clad laminate (FCCL) using a thin copper plate as a metal foil. In addition, polyimide is also used as a protective film and insulating film for thin circuit boards.

Meanwhile, as various functions are embedded in electronic devices in recent years, a high computational speed and communication speed are required for the electronic devices, and to meet this demand, a thin circuit board capable of high-speed communication at high frequencies has been developed.

In order to realize high-frequency high-speed communication, there is a need for an insulator having a high impedance capable of maintaining electrical insulation even at high frequencies. 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 in order to maintain insulation even at high frequencies.

However, in the case of a conventional polyimide, the dielectric properties are not excellent enough to maintain sufficient insulation in high-frequency communication.

In addition, it is known that as the insulator has a low dielectric property, undesirable stray capacitance and noise generation in a thin circuit board can be reduced, thereby significantly reducing the cause of communication delay.

Therefore, polyimide with low dielectric properties is recognized as an important factor in the performance of thin circuit boards.

In particular, in the case of high-frequency communication, dielectric dissipation through polyimide inevitably occurs. The dielectric dissipation factor (Df) refers to the degree of wasted electrical energy of a thin circuit board, and is closely related to the signal transmission delay that determines the communication speed, so it is also possible to keep the dielectric loss rate of polyimide as low as possible. It is recognized as an important factor in the performance of the substrate.

Also, as more moisture is included in the polyimide film, the dielectric constant increases and the dielectric loss rate increases. The polyimide film is suitable as a material for a thin circuit board due to its excellent intrinsic properties, but may be relatively vulnerable to moisture due to polar imide groups, and thus insulation properties may be deteriorated.

Therefore, while maintaining the mechanical properties, thermal properties, and chemical resistance characteristics peculiar to polyimide at a certain level, it is necessary to develop a polyimide film having dielectric properties, in particular, a low dielectric loss rate.

Accordingly, in order to solve the above problems, an object of the present invention is to provide a polyimide film having high heat resistance, low dielectric characteristics, and low moisture absorption characteristics, and a method of manufacturing the same.

Accordingly, the present invention has a practical purpose to provide a specific embodiment thereof.

One embodiment of the present invention for achieving the above object is benzophenone tetracarboxylic dianhydride (3,3',4,4'-Benzophenonetetracarboxylic dianhydride, BTDA) and biphenyltetracarboxylic dianhydride (3,3',4,4'-Biphenyltetracarboxylic dianhydride, BPDA) containing a dianhydride component and paraphenylene diamine (p-Phenylenediamine, PPD) a first block obtained by the imidization reaction of the diamine component including the; And

The second obtained by imidization reaction of a dianhydride component including benzophenone tetracarboxylic dianhydride and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine It provides a polyimide film comprising a block copolymer including;

The content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% or more, based on 100 mol% of the total content of the diamine component of the first block and the second block. It may be less than or equal to mole %.

In addition, the content of benzophenone tetracarboxylicdianhydride is 25 mol% or more and 45 mol% or less, based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxyl The content of rickdian hydride may be 25 mol% or more and 45 mol% or less, and the content of pyromellitic dianhydride may be 15 mol% or more and 40 mol% or less.

The polyimide film may have a dielectric loss factor (Df) of 0.004 or less, a thermal expansion coefficient (CTE) of 15 ppm/°C or less, and a glass transition temperature (Tg) of 320°C or more.

Another embodiment of the present invention includes the steps of (a) polymerizing a first dianhydride component and a first diamine component in an organic solvent to prepare a first polyamic acid;

(b) polymerizing a second dianhydride component and a second diamine component in an organic solvent to prepare a second polyamic acid;

(c) copolymerizing the first polyamic acid and the second polyamic acid in an organic solvent to prepare a third polyamic acid; And

(d) comprising the step of imidizing after forming a film of a precursor composition containing the third polyamic acid on a support,

The first dianhydride component includes benzophenone tetracarboxylic dianhydride and biphenyl tetracarboxylic dianhydride,

The second dianhydride component includes benzophenone tetracarboxylic dianhydride and pyromellitic dianhydride,

The first diamine component includes paraphenylene diamine,

The second diamine component provides a method for producing a polyimide film containing m-tolidine.

As described above, the present invention provides a polyimide film having high heat resistance, low dielectric properties, and low moisture absorption through a polyimide film composed of a specific component and a specific composition ratio, and a manufacturing method thereof. It can be usefully applied to various fields, especially electronic components such as flexible metal foil laminates.

Hereinafter, embodiments of the present invention will be described in more detail in the order of "polyimide film" and "manufacturing method of polyimide film" according to the present invention.

Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

Therefore, the configuration of the embodiments described in the present specification is only one of the most preferred embodiments of the present invention, and does not represent all the technical spirit of the present invention, and various equivalents and modifications that can replace them at the time of application It should be understood that examples may exist.

In the present specification, expressions in the singular include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include", or "have" are intended to designate the existence of a feature, number, step, element, or combination of the implemented features, but one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

Where an amount, concentration, or other value or parameter herein is given as an enumeration of a range, a preferred range, or a preferred upper and lower preferred value, any pair of any upper range limits, or It is to be understood that the preferred values and any lower range limits or all ranges formed with preferred values are specifically disclosed.

Ranges of numerical values are intended to include the endpoints and all integers and fractions within that range, unless stated otherwise, when a range is referred to herein. It is intended that the scope of the invention is not limited to the specific values recited when defining the range.

In the present specification, "dianhydric acid" is intended to include a precursor or derivative thereof, which may not technically be a dianhydride acid, but nevertheless will react with a diamine to form a polyamic acid, and the polyamic acid is again polyamic acid. Can be converted to mid.

In the present specification, "diamine" is intended to include precursors or derivatives thereof, which may not technically be diamines, but nevertheless will react with dianhydride to form polyamic acid, which polyamic acid is again polyamic acid. Can be converted to mid.

The polyimide film according to the present invention is a diamine containing a dianhydride component including benzophenonetetracarboxylicdianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and paraphenylene diamine (PPD). A first block obtained by imidation reaction of a component; And

A second block obtained by imidization reaction of a dianhydride component including benzophenone tetracarboxylic dianhydride and pyromellitic dianhydride and a diamine component including m-tolidine; comprising a block copolymer comprising It is a polyimide film.

The content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% or more, based on 100 mol% of the total content of the diamine component of the first block and the second block. And a first block obtained by imidization reaction of a dianhydride component including biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including paraphenylene diamine (PPD); And

A second block obtained by imidization reaction of a dianhydride component including benzophenone tetracarboxylic dianhydride and pyromellitic dianhydride and a diamine component including m-tolidine; comprising a block copolymer comprising It is a polyimide film.

The content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% or more, based on 100 mol% of the total content of the diamine component of the first block and the second block. It may be less than or equal to mole %.

Especially. In particular, m-tolidine has a hydrophobic methyl group, which contributes to the low moisture absorption properties of the polyimide film.

In addition, the content of benzophenone tetracarboxylicdianhydride is 25 mol% or more and 45 mol% or less, based on 100 mol% of the total content of the dianhydride component of the first block and the second block, and biphenyltetracarboxyl The content of rickdian hydride may be 25 mol% or more and 45 mol% or less, and the content of pyromellitic dianhydride may be 15 mol% or more and 40 mol% or less.

In particular, the content of the benzophenone tetracarboxylic dianhydride is 25 mol% or more and 40 mol% or less, the content of the biphenyl tetracarboxylic dianhydride is 30 mol% or more and 45 mol% or less, and pyromellitic dian It is preferable that the content of hydride is 20 mol% or more and 40 mol% or less.

The polyimide chain derived from the biphenyltetracarboxylic dianhydride of the present invention has a structure named as a charge transfer complex (CTC), that is, an electron donor and an electron acceptor. They have regular linear structures that are located close to each other, and intermolecular interactions are strengthened.

In addition, benzophenonetetracarboxylicdianhydride, which has a carbonyl group, also contributes to the expression of CTC like biphenyltetracarboxylicdianhydride.

Since this structure has an effect of preventing hydrogen bonding with moisture, it has an effect on lowering the moisture absorption rate, thereby maximizing the effect of lowering the hygroscopicity of the polyimide film.

In one specific example, the dianhydride component may additionally include pyromellitic dianhydride. Pyromellitic dianhydride is a dianhydride component having a relatively rigid structure and is preferable in that it can impart appropriate elasticity to the polyimide film.

In order for the polyimide film to simultaneously satisfy the appropriate elasticity and moisture absorption rate, the content ratio of dianhydride is particularly important. For example, as the content ratio of biphenyltetracarboxylic dianhydride decreases, it becomes difficult to expect a low moisture absorption rate due to the CTC structure.

In addition, biphenyltetracarboxylic dianhydride and benzophenone tetracarboxylicdianhydride contain two benzene rings corresponding to the aromatic moiety, whereas pyromellitic dianhydride contains benzene rings corresponding to the aromatic moiety. I include one.

It can be understood that the increase in the content of pyromellitic dianhydride in the dianhydride component increases the imide group in the molecule based on the same molecular weight, which is an image derived from the pyromellitic dianhydride in the polyimide polymer chain. It can be understood that the ratio of the radical increases relative to the imide group derived from biphenyltetracarboxylic dianhydride and benzophenonetetracarboxylicdianhydride.

That is, the increase in the content of pyromellitic dianhydride can be seen as a relative increase in the imide group even for the entire polyimide film, which makes it difficult to expect a low moisture absorption rate.

Conversely, when the content ratio of pyromellitic dianhydride decreases, the component of a relatively rigid structure decreases, so that the elasticity of the polyimide film may be lowered to a desired level or less.

For this reason, when the content of the biphenyltetracarboxylic dianhydride and benzophenonetetracarboxylicdianhydride exceeds the above range, or the content of pyromellitic dianhydride is less than the above range, the polyimide film Mechanical properties deteriorate, and heat resistance at an appropriate level for manufacturing a ductile metal foil laminate cannot be secured.

Conversely, when the content of the biphenyltetracarboxylic dianhydride and benzophenonetetracarboxylicdianhydride is less than the above range, or the content of pyromellitic dianhydride exceeds the above range, an appropriate level of genetics It is not preferable because it is difficult to achieve the constant, dielectric loss rate and moisture absorption rate.

The polyimide film may have a dielectric loss factor (Df) of 0.004 or less, a thermal expansion coefficient (CTE) of 15 ppm/°C or less, and a glass transition temperature (Tg) of 320°C or more.

In this regard, in the case of a polyimide film that satisfies all of the dielectric loss rate (Df), glass transition temperature, and moisture absorption rate, it can be used as an insulating film for a flexible metal clad laminate, and the manufactured flexible metal clad laminate transmits a signal at a high frequency of 10 GHz or higher. Even if it is used as a transmitting electrical signal transmission circuit, its insulation stability can be ensured, and signal transmission delay can also be minimized.

The polyimide film having all of the above conditions is a novel polyimide film that has not been known so far, and the dielectric loss factor (Df) will be described in detail below.

<Dielectric loss rate>

"Dielectric loss rate" means the force dissipated by the dielectric (or insulator) when the friction of the molecules interferes with the molecular motion caused by the alternating electric field.

The value of the dielectric loss rate is commonly used as an index indicating the ease of dissipation (dielectric loss), and the higher the dielectric loss rate, the easier it is to dissipate the charge. Conversely, the lower the dielectric loss rate, the more difficult it is to dissipate the charge. have. That is, since the dielectric loss rate is a measure of the power loss, the lower the dielectric loss rate, the faster the communication speed can be maintained while the signal transmission delay due to the power loss is alleviated.

This is strongly required for the polyimide film, which is an insulating film, and the polyimide film according to the present invention may have a dielectric loss rate of 0.004 or less under a very high frequency of 10 GHz.

Preparation of the polyamic acid in the present invention, for example,

(1) A method of polymerizing by putting the entire amount of the diamine component in a solvent, and then adding the dianhydride component so as to be substantially equimolar with the diamine component;

(2) a method of polymerizing by putting the entire amount of the dianhydride component into a solvent, and then adding the diamine component so as to be substantially equimolar with the dianhydride component;

(3) After adding some components of the diamine component to the solvent, mixing some components of the dianhydride component with respect to the reaction component in a ratio of about 95 to 105 mol%, the remaining diamine component is added, and the remaining dianhydride is successively A method of polymerization by adding a component so that the diamine component and the dianhydride component become substantially equimolar;

(4) After the dianhydride component is added to the solvent, some components of the diamine compound are mixed in a ratio of 95 to 105 mol% with respect to the reaction component, and then another dianhydride component is added, followed by addition of the remaining diamine component, A method of polymerization by making the diamine component and the dianhydride component substantially equimolar;

(5) In a solvent, some diamine components and some dianhydride components are reacted so that any one is in excess to form a first composition, and in another solvent, some diamine components and some dianhydride components are reacted so that any one is in excess. 2 As a method of mixing the first and second compositions after forming the composition, and completing polymerization. In this case, when the diamine component is excessive when forming the first composition, the dianhydride component is used in an excessive amount in the second composition. And, when the dianhydride component is excessive in the first composition, the diamine component is used in an excessive amount in the second composition, and the first and second compositions are mixed so that the total diamine component and the dianhydride component used in these reactions are substantially, etc. And a method of polymerization by making it mol.

However, the polymerization method is not limited to the above examples, and of course, any known method may be used to prepare the first to third polyamic acids.

In one specific example, the method of manufacturing a polyimide film according to the present invention,

(a) polymerizing a first dianhydride component and a first diamine component in an organic solvent to prepare a first polyamic acid;

(b) polymerizing a second dianhydride component and a second diamine component in an organic solvent to prepare a second polyamic acid;

(c) copolymerizing the first polyamic acid and the second polyamic acid in an organic solvent to prepare a third polyamic acid; And

(d) comprising the step of imidizing after forming a film of a precursor composition containing the third polyamic acid on a support,

The first dianhydride component includes benzophenone tetracarboxylic dianhydride and biphenyl tetracarboxylic dianhydride,

The second dianhydride component includes benzophenonetetracarboxylicdianhydride and pyromellitic dianhydride, the first diamine component includes paraphenylene diamine, and the second diamine component includes m-tolidine. Can include.

Based on 100 mol% of the total content of the diamine component of the first polyamic acid and the second polyamic acid, the content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% It may be more than 90 mol% or less.

In addition, the content of benzophenonetetracarboxylicdianhydride is 25 mol% or more and 45 mol% or less, based on 100 mol% of the total content of the dianhydride component of the first polyamic acid and the second polyamic acid, and biphenyltetra The content of carboxylic dianhydride may be 25 mol% or more and 45 mol% or less, and the content of pyromellitic dianhydride (PMDA) may be 15 mol% or more and 40 mol% or less.

In the present invention, the polymerization method of the polyamic acid as described above can be defined as a random polymerization method, and the polyimide film prepared from the polyamic acid of the present invention prepared by the above process has a dielectric loss factor (Df) and It can be preferably applied in terms of maximizing the effect of the present invention to lower the moisture absorption rate.

However, in the polymerization method, since the length of the repeating unit in the polymer chain described above is relatively short, there may be limitations in exhibiting the excellent properties of each polyimide chain derived from a dianhydride component. Therefore, the polymerization method of the polyamic acid that can be particularly preferably used in the present invention may be a block polymerization method.

On the other hand, the solvent for synthesizing the polyamic acid is not particularly limited, and any solvent may be used as long as it dissolves the polyamic acid, but it is preferably an amide solvent.

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

In one example, N,N-dimethylformamide and N,N-dimethylacetamide may be particularly preferably used as the solvent.

In addition, in the polyamic acid manufacturing process, a filler may be added for the purpose of improving various properties of the film such as sliding properties, thermal conductivity, corona resistance, and loop hardness. The filler to be added is not particularly limited, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like.

The particle diameter of the filler is not particularly limited, and may be determined according to the film properties to be modified and the type of filler to be added. In general, the average particle diameter is 0.05 to 100 µm, preferably 0.1 to 75 µm, more preferably 0.1 to 50 µm, and particularly preferably 0.1 to 25 µm.

If the particle diameter is less than this range, the modification effect is difficult to appear, and if it exceeds this range, the surface properties may be greatly impaired, or the mechanical properties may be greatly reduced.

In addition, the amount of the filler added is not particularly limited, and may be determined according to the film properties to be modified, the filler particle size, or the like. In general, the amount of the filler added is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, more preferably 0.02 to 80 parts by weight, based on 100 parts by weight of the polyimide.

If the amount of the filler added is less than this range, the effect of modifying by the filler is difficult to appear, and if it exceeds this range, there is a possibility that the mechanical properties of the film will be greatly impaired. 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 may be manufactured by thermal imidization and chemical imidization.

Further, it may be produced by a composite imidization method in which a thermal imidation method and a chemical imidization method are combined.

The thermal imidation method is a method of inducing an imidation reaction with a heat source such as hot air or an infrared dryer, excluding a chemical catalyst.

In the thermal imidation method, the gel film may be heat-treated at a variable temperature in the range of 100 to 600° C. to imidize the amic acid group present in the gel film, and in detail, 200 to 500° C., more specifically, The amic acid group present in the gel film may be imidized by heat treatment at 300 to 500°C.

However, even in the process of forming the gel film, some of the amic acid (about 0.1 mol% to 10 mol%) may be imidized, and for this purpose, the polyamic acid composition may be dried at a variable temperature in the range of 50 °C to 200 °C. It can be, and this can also be included in the category of the thermal imidization method.

In the case of the chemical imidization method, a polyimide film may be prepared by using a dehydrating agent and an imidizing agent according to a method known in the art.

As an example of the complex imidization method, after adding a dehydrating agent and an imidizing agent to the polyamic acid solution, heating at 80 to 200°C, preferably 100 to 180°C, partially curing and drying, at 200 to 400°C for 5 to 400 seconds By heating, a polyimide film can be produced.

The polyimide film of the present invention manufactured according to the above manufacturing method has a dielectric loss factor (Df) of 0.004 or less, a thermal expansion coefficient (CTE) of 15 ppm/°C or less, and a glass transition temperature (Tg) of 320°C or more. I can.

The present invention provides a multilayer film comprising the above-described polyimide film and a thermoplastic resin layer, and a flexible metal foil laminate comprising the above-described polyimide film and an electrically conductive metal foil.

As the thermoplastic resin layer, for example, a thermoplastic polyimide resin layer or the like may be applied.

The metal foil to be used is not particularly limited, but when the flexible metal foil laminate of the present invention is used for electronic devices or electric devices, for example, copper or copper alloy, stainless steel or alloy thereof, nickel or nickel alloy (alloy 42 Also included), it may be a metal foil containing aluminum or an aluminum alloy.

In a general flexible metal foil laminate, many copper foils such as rolled copper foil and electrolytic copper foil are used, and can be preferably used also in the present invention. In addition, a rust prevention layer, a heat-resistant layer, or an adhesive layer may be applied to the surface of these metal foils.

In the present invention, the thickness of the metal foil is not particularly limited, and may be any thickness capable of exhibiting a sufficient function according to the application.

In the flexible metal foil laminate according to the present invention, a metal foil is laminated on one side of the polyimide film, or an adhesive layer containing a thermoplastic polyimide is added to one side of the polyimide film, and the metal foil is attached to the adhesive layer. It may be a laminated structure.

The present invention also provides an electronic component including the flexible metal foil laminate as an electrical signal transmission circuit. The electrical signal transmission circuit may be an electronic component that transmits a signal at a high frequency of at least 2 GHz, in detail, a high frequency of at least 5 GHz, and more particularly, a high frequency of at least 10 GHz.

The electronic component may be, for example, a communication circuit for a portable terminal, a communication circuit for a computer, or a communication circuit for aerospace, but is not limited thereto.

Hereinafter, the action and effect of the invention will be described in more detail through specific embodiments of the invention. However, these embodiments are only presented as examples of the invention, and the scope of the invention is not determined thereby.

<Example 1>

In 500 ml reactor equipped with a stirrer and nitrogen inlet/discharge pipe, NMP was introduced while nitrogen was injected, and the temperature of the reactor was set to 30°C. Paraphenylene diamine as a diamine component, and benzophenone tetracarboxylicdian as a dianhydride component. Hydride and biphenyltetracarboxylic dianhydride are added to confirm that they are completely dissolved. After the temperature was raised to 40° C. in a nitrogen atmosphere and stirring was continued for 120 minutes while heating, a first polyamic acid having a viscosity of 200,000 cP at 23° C. was prepared.

In 500 ml reactor equipped with agitator and nitrogen inlet/discharge pipe, NMP was introduced while nitrogen was injected, and the temperature of the reactor was set to 30°C. Ride and pyromellitic dianhydride are added to confirm that they are completely dissolved. After the temperature was raised to 40° C. in a nitrogen atmosphere and stirring was continued for 120 minutes while heating, a second polyamic acid having a viscosity of 200,000 cP at 23° C. was prepared.

Then, the first polyamic acid and the second polyamic acid were heated to 40° C. in a nitrogen atmosphere, and stirred for 120 minutes while heating, and then the final viscosity at 23° C. was 200,000 cP, and the diamine component and dianhydride acid A third polyamic acid containing components as shown in Table 1 was prepared.

Air bubbles were removed by rotating the third polyamic acid prepared above at a high speed of 1,500 rpm or more. Thereafter, the defoamed polyimide precursor composition was applied to the glass substrate using a spin coater. Thereafter, a gel film was prepared by drying in a nitrogen atmosphere and at a temperature of 120° C. for 30 minutes, and the gel film was heated to 450° C. at a rate of 2° C./min, heat-treated at 450° C. for 60 minutes, and then until 30° C. It cooled at a rate of 2° C./min to obtain a polyimide film.

Thereafter, the polyimide film was peeled off from the glass substrate by dipping in distilled water. The thickness of the prepared polyimide film was 15 µm. The thickness of the prepared polyimide film was measured using an Anritsu's Electric Film thickness tester.

<Examples 2 to 6 and Comparative Examples 1 to 4>

In Example 1, a polyimide film was prepared in the same manner as in Example 1, except that the components and their contents were respectively changed as shown in Table 1 below.

	Dianhydride component (mol%)			Diamine component (mol%)		Polyamic acid polymerization method
	BPDA (mol%)	BTDA (mol%)	PMDA (mol%)	m-Tolidine (mol%)	PPD (mol%)
Example 1	40	30	30	20	80	Block polymerization
Example 2	35	32	33	30	70	Block polymerization
Example 3	40	40	20	20	80	Block polymerization
Example 4	44	28	28	12	88	Block polymerization
Example 5	30	32	38	40	60	Block polymerization
Example 6	35	20	45	48	52	Block polymerization
Comparative Example 1	40	17	43	40	60	Block polymerization
Comparative Example 2	30	14	56	40	60	Block polymerization
Comparative Example 3	35	17	48	30	70	Block polymerization
Comparative Example 4	40	20	40	20	80	Block polymerization

<Experimental Example 1> Evaluation of dielectric loss factor, coefficient of thermal expansion, and glass transition temperature

For the polyimide films prepared in Examples 1 to 6 and Comparative Examples 1 to 4, respectively, dielectric loss ratio, coefficient of thermal expansion, and glass transition temperature were measured, and the results are shown in Table 2 below.

(1) Measurement of dielectric loss rate

The dielectric loss factor (Df) was measured by leaving the flexible metal foil laminate for 72 hours using an ohmmeter Agilent 4294A.

(2) Measurement of coefficient of thermal expansion

For the coefficient of thermal expansion (CTE), a Q400 model of a thermomechanical analyzer from TA was used, and a polyimide film was cut into a width of 4 mm and a length of 20 mm, and a tension of 0.05 N was applied in a nitrogen atmosphere, while 10 ℃/min. After raising the temperature from room temperature to 300°C at a rate of 10°C/min, the slope of the 100°C to 200°C section was measured while cooling at a rate of 10°C/min.

(3) Glass transition temperature measurement

The glass transition temperature (T _g ) was obtained by using DMA to determine the loss modulus and storage modulus of each film, and the inflection point was measured as a glass transition degree in the tangent graph.

	Df	CTE(ppm/℃)	Tg(℃)
Example 1	0.0036	9.0	358
Example 2	0.0036	8.5	350
Example 3	0.0033	12.0	340
Example 4	0.0035	8.5	348
Example 5	0.0036	8.1	340
Example 6	0.0034	7.4	325
Comparative Example 1	0.0041	0.3	326
Comparative Example 2	0.0047	0.3	360
Comparative Example 3	0.0040	3.4	368
Comparative Example 4	0.0043	8.4	350

As shown in Table 2, the polyimide film prepared according to the embodiment of the present invention not only exhibits a remarkably low dielectric loss rate, such as 0.004 or less, but also has a desired level of thermal expansion coefficient and glass transition temperature.

These results are achieved by the components and composition ratios specified herein, and it can be seen that the content of each component plays a decisive role.

On the other hand, the examples show that it is difficult to be used for electronic components in which signals are transmitted at high frequency in giga units in more than one aspect of dielectric loss ratio, coefficient of thermal expansion, and glass transition temperature compared to the polyimide films of Comparative Examples 1 to 4 having different components. Can be expected.

Although the above has been described with reference to the embodiments of the present invention, a person of ordinary skill in the field to which the present invention belongs will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

The present invention provides a polyimide film having high heat resistance, low dielectric properties, and low moisture absorption through a polyimide film composed of a specific component and a specific composition ratio, and a manufacturing method thereof, thereby providing a polyimide film having such characteristics It can be usefully applied to electronic components such as laminates.

Claims (11)

1. Agent obtained by imidization reaction of a dianhydride component including benzophenonetetracarboxylicdianhydride (BTDA) and biphenyltetracarboxylic dianhydride (BPDA) and a diamine component including paraphenylene diamine (PPD) 1 block; And

   The second obtained by imidization reaction of a dianhydride component including benzophenonetetracarboxylicdianhydride (BTDA) and pyromellitic dianhydride (PMDA) and a diamine component including m-tolidine Block; including a block copolymer containing,

   Polyimide film.
2. The method of claim 1,

   The content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% or more, based on 100 mol% of the total content of the diamine component of the first block and the second block. Less than or equal to mole %,

   Polyimide film.
3. The method of claim 1,

   The content of benzophenonetetracarboxylicdianhydride is 25 mol% or more and 45 mol% or less, based on 100 mol% of the total content of the dianhydride component of the first block and the second block,

   The content of biphenyltetracarboxylic dianhydride is 25 mol% or more and 45 mol% or less,

   The content of pyromellitic dianhydride is 15 mol% or more and 40 mol% or less,

   Polyimide film.
4. The method of claim 1,

   The dielectric loss factor (Df) is 0.004 or less,

   The coefficient of thermal expansion (CTE) is 15 ppm/℃ or less,

   Glass transition temperature (Tg) of 320℃ or higher,

   Polyimide film.
5. (a) polymerizing a first dianhydride component and a first diamine component in an organic solvent to prepare a first polyamic acid;

   (b) polymerizing a second dianhydride component and a second diamine component in an organic solvent to prepare a second polyamic acid;

   (c) copolymerizing the first polyamic acid and the second polyamic acid in an organic solvent to prepare a third polyamic acid; And

   (d) comprising the step of imidizing after forming a film of a precursor composition containing the third polyamic acid on a support,

   The first dianhydride component includes benzophenone tetracarboxylic dianhydride (BTDA) and biphenyl tetracarboxylic dianhydride (BPDA),

   The second dianhydride component includes benzophenone tetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA),

   The first diamine component includes paraphenylene diamine (PPD),

   The second diamine component comprises m-tolidine (m-tolidine),

   Method for producing a polyimide film.
6. The method of claim 5,

   Based on 100 mol% of the total content of the first diamine component and the second diamine component, the content of m-tolidine is 10 mol% or more and 50 mol% or less, and the content of paraphenylene diamine is 50 mol% or more and 90 mol % Or less,

   Method for producing a polyimide film.
7. The method of claim 5,

   The content of benzophenone tetracarboxylic dianhydride is 25 mol% or more and 45 mol% or less, based on 100 mol% of the total content of the first dianhydride acid and the second dianhydride component,

   The content of biphenyltetracarboxylic dianhydride is 25 mol% or more and 45 mol% or less,

   The content of pyromellitic dianhydride is 15 mol% or more and 40 mol% or less,

   Method for producing a polyimide film.
8. The method of claim 5,

   The dielectric loss factor (Df) is 0.004 or less,

   The coefficient of thermal expansion (CTE) is 15 ppm/℃ or less,

   Glass transition temperature (Tg) of 320℃ or higher,

   Method for producing a polyimide film.
9. A multilayer film comprising the polyimide film according to any one of claims 1 to 4 and a thermoplastic resin layer.
10. A flexible metal foil laminate comprising the polyimide film according to any one of claims 1 to 4 and an electrically conductive metal foil.
11. An electronic component comprising the flexible metal foil laminate according to claim 10.