KR20210052283A - Resin composition, resin film and metal clad laminate - Google Patents

Abstract

The present invention provides a resin composition and a resin film, which can improve dielectric properties without impairing mechanical properties such as bendability, etc., due to the addition of an inorganic filler. The resin composition contains polyamic acid or polyimide and spherical silica particles, and the frequency distribution curve of the spherical silica particles obtained by volume-based particle size distribution measurement by laser diffraction scattering satisfies the followings: a) the average particle diameter (D_50) at a cumulative value of 50% is in the range of 9.0 to 12.0 ㎛; b) the particle diameter (D_90) at a cumulative value of 90% is in the range of 15 to 20 ㎛; and c) the particle diameter (D_100) at a cumulative value of 100% is 25 ㎛ or less. The content of the spherical silica particles is within the range of 20 to 65 vol% with respect to the polyamic acid or polyimide.

Description

Resin composition, resin film and metal clad laminate {RESIN COMPOSITION, RESIN FILM AND METAL CLAD LAMINATE}

The present invention relates to a resin composition containing spherical silica particles as inorganic fillers, a resin film using the same, and a metal-clad laminate.

In recent years, as represented by mobile phones, LED lighting fixtures, and related parts around automobile engines, the demand for miniaturization and weight reduction of electronic devices is increasing. Along with this, flexible circuit boards, which are advantageous for reducing the size and weight of devices, have come to be widely used in the field of electronic technology. And, among them, a flexible circuit board made of polyimide as an insulating layer is widely used because of its excellent heat resistance, chemical resistance, and the like.

On the other hand, high-speed transmission of information is advancing along with higher performance and higher functionality of electric and electronic devices. Therefore, there is a demand for high-speed transmission for parts and members used in electric and electronic equipment. For resin materials used for such a purpose, attempts have been made to achieve low dielectric constant and low dielectric tangent so as to have electrical properties corresponding to high-speed transmission. As an example, having a resin mixture containing an epoxy resin, a polyimide resin, and an aromatic polyamide resin, an imidazole-based curing catalyst, and a resin layer containing an inorganic filler, and a resin having dielectric properties corresponding to high frequency transmission. Copper foil has been proposed (for example, Patent Document 1).

International Disclosure WO2017/014079

In Patent Document 1, although it is described that the dielectric loss tangent of the resin layer can be reduced by the addition of an inorganic filler such as silica, detailed examination has not been made on the specific configuration of an inorganic filler suitable for the purpose. In addition, there is a problem that the addition of the inorganic filler exerts an influence such as lowering the bendability of the resin film.

An object of the present invention is to provide a resin composition and a resin film in which dielectric properties are improved without impairing mechanical properties such as bendability by addition of an inorganic filler.

The resin composition of the present invention is a resin composition containing polyamic acid or polyimide and spherical silica particles. In the resin composition of the present invention, the frequency distribution curve of the spherical silica particles obtained by volume-based particle size distribution measurement by a laser diffraction scattering method satisfies the following conditions a to c, and the content of the spherical silica particles, It is within the range of 20 to 65% by volume based on the polyamic acid or the polyimide.

_{a) The average particle diameter D 50} at which the cumulative value is 50% is in the range of 9.0 to 12.0 µm.

_{b) The particle diameter D 90} at which the cumulative value is 90% is within the range of 15 to 20 µm.

_{c) The particle diameter D 100} at which the cumulative value is 100% is 25 μm or less.

In the resin composition of the present invention, the spherical silica particles may further satisfy the following condition d.

d) Having a frequency maximum value F1 and a frequency maximum value F2, wherein the F1 is in a region of 9.0 to 14.0 µm, and the F2 is in a region of 0.5 to 3.0 µm.

In the resin composition of the present invention, the spherical silica particles may further satisfy the following condition e.

e) It has a frequency maximum value F1 and a frequency maximum value F2, and the ratio (F1/F2) of F1 and F2 is in the range of 3 to 28.

The resin film of the present invention is a resin film having a single layer or a plurality of polyimide layers, wherein at least one of the polyimide layers is a spherical silica-containing polyimide layer containing a cured product of the above resin composition, and The thickness of the spherical silica-containing polyimide layer is in the range of 5 to 150 µm.

In the resin film of the present invention, the particle diameter D ₁₀₀ of the spherical silica particles may be in the range of 0.05 to 0.7 with respect to the thickness of the spherical silica-containing polyimide layer.

The resin film of the present invention may have a thickness in the range of 5 to 150 µm, and the ratio of the thickness of the spherical silica-containing polyimide layer may be 50% or more.

The metal-clad laminate of the present invention is a metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one side of the insulating resin layer, and the insulating resin layer includes the resin film.

When the resin composition of the present invention contains spherical silica particles having a specific particle size distribution represented by conditions a to c, it becomes possible to improve dielectric properties without deteriorating mechanical properties such as bendability. Therefore, in an electric/electronic device or electronic component using the resin composition of the present invention, it is possible to cope with high-speed transmission and secure reliability.

Hereinafter, an embodiment of the present invention will be described.

[Resin composition]

The resin composition according to an embodiment of the present invention is a resin composition containing polyamic acid or polyimide and spherical silica particles which are inorganic fillers. The resin composition may be a varnish (resin solution) containing a polyamic acid, or a polyimide solution containing a solvent-soluble polyimide.

<Polyamic acid or polyimide>

Polyimide is generally represented by the following general formula (1). Such a polyimide can be produced by a known method in which a diamine component and an acid dianhydride component are used in substantially equimolar amounts, and polymerized in an organic polar solvent. In this case, in order to make the viscosity within a desired range, the molar ratio of the acid dianhydride component to the diamine component may be adjusted, and the range is preferably in the range of, for example, 0.980 to 1.03.

Here, Ar ₁ is a tetravalent organic _{group having at least one aromatic ring, and Ar 2} is a divalent organic group having at least one aromatic ring. And Ar ₁ can be said to be a residue of an acid dianhydride, and Ar ₂ can be said to be a residue of a diamine. In addition, n represents the number of repetitions of the structural unit of the general formula (1), and is 200 or more, and preferably a number of 300 to 1000.

As the acid dianhydride, for example, _{an aromatic tetracarboxylic dianhydride represented by O(OC) 2} -Ar ₁ -(CO) ₂ O is preferable, and the following aromatic acid anhydride residue is given as _{Ar 1.} do.

The acid dianhydride may be used alone or in combination of two or more. Among these, pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenonetetracarboxylic acid It is recommended to use one selected from dianhydride (BTDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), and 4,4'-oxydiphthalic dianhydride (ODPA). desirable.

As the diamine, for example, _{an aromatic diamine represented by H 2} N-Ar ₂ -NH ₂ is preferable, and an aromatic diamine _{giving the following aromatic diamine residue as Ar 2} is exemplified.

Among these diamines, diaminodiphenyl ether (DAPE), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), paraphenylenediamine (p-PDA), 1,3-bis (4-aminophenoxy)benzene (TPE-R), 1,3-bis(3-aminophenoxy)benzene (APB), 1,4-bis(4-aminophenoxy)benzene (TPE-Q), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and 2,2-bis(trifluoromethyl)benzidine (TFMB) are exemplified as suitable.

The polyimide can be produced by reacting an acid dianhydride and a diamine compound in a solvent to produce a precursor polyamic acid, followed by heat ring closure (imidization). For example, a polyamic acid is obtained by dissolving an acid dianhydride and a diamine compound in an organic solvent in substantially equimolar amounts and stirring at a temperature within the range of 0 to 100°C for 30 minutes to 24 hours for a polymerization reaction. During the reaction, the reaction component is dissolved so that the resulting precursor is in the range of 5 to 30% by weight, preferably 10 to 20% by weight in the organic solvent. Examples of the organic solvent used in the polymerization reaction include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, and N-methyl-2-pi. Rolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme And cresols. Two or more of these solvents may be used in combination, and further, aromatic hydrocarbons such as xylene and toluene may be used in combination. Further, the amount of the organic solvent to be used is not particularly limited, but it is preferable to use it by adjusting the concentration of the polyamic acid solution obtained by the polymerization reaction to an amount of about 5 to 30% by weight.

The synthesized polyamic acid is usually advantageously used as a reaction solvent solution, but the resin composition can be formed by concentrating, diluting, or substituting another organic solvent as necessary. The method of imidizing the polyamic acid is not particularly limited, and for example, a heat treatment such as heating for 1 to 24 hours in the above solvent at a temperature condition within the range of 80 to 400°C is suitably employed.

<Spherical silica particles>

Spherical silica particles are silica particles whose shape is close to a spherical shape, and the ratio between the average long diameter and the average short diameter is 1 or close to 1. As for the spherical silica particles, the frequency distribution curve obtained by volume-based particle size distribution measurement by the laser diffraction scattering method satisfies the following conditions a to c.

_{a) The average particle diameter D 50} at which the cumulative value is 50% is in the range of 9.0 to 12.0 µm.

_{b) The particle diameter D 90} at which the cumulative value is 90% is within the range of 15 to 20 µm.

_{c) The particle diameter D 100} at which the cumulative value is 100% is 25 μm or less.

In condition a, when the average particle diameter D ₅₀ of the spherical silica particles is less than 9.0, the effect of improving the dielectric properties becomes small. On the other hand, when the average particle diameter D ₅₀ exceeds 12.0 µm, it becomes difficult to fill, or when a resin film is formed, the bendability decreases, and it becomes difficult to maintain mechanical properties.

For conditions b and c, the presence ratio of spherical silica particles having a particle diameter of 15 to 25 µm is suppressed, and coarse particles are excluded when the maximum particle size is 25 µm or less, so that the bendability when a resin film is formed Can be made good.

In addition, it is preferable that the spherical silica particles also satisfy the following conditions d and e.

d) Having the maximum frequency value F1 and the maximum frequency value F2, F1 is in a region of 9.0 to 14.0 µm and F2 is in a region of 0.5 to 3.0 µm.

e) Having a frequency maximum value F1 and a frequency maximum value F2, and the ratio (F1/F2) of F1 and F2 is in the range of 3 to 28.

As for the condition d and the condition e, by containing a certain amount of small spherical silica having a particle diameter in the range of 0.5 to 3.0 µm in the spherical silica particles, it is possible to further improve the dielectric properties while suppressing a decrease in the bendability when formed into a film.

In addition, the spherical silica particles can be used by appropriately selecting a commercial item. For example, spherical cristobalite silica powder (manufactured by Nittetsu Chemical & Materials, brand name; CR10-20), spherical amorphous silica powder (manufactured by Nittetsu Chemical & Materials, brand name; SC70-2), etc. can be preferably used. . These can use 2 or more types together.

<Composition composition>

The content of the spherical silica particles in the resin composition is in the range of 20 to 65% by volume, preferably 30 to 60% by volume with respect to the polyamic acid or polyimide. If the content ratio of the spherical silica particles is less than 20% by volume, the effect of lowering the dielectric loss tangent will not be sufficiently obtained. In addition, when the content ratio of the spherical silica particles exceeds 65% by volume, when the resin film is formed, it is fragile, the bendability decreases, and when a resin film is to be formed, the viscosity of the resin composition increases, resulting in a decrease in workability. do.

The resin composition of this embodiment can contain an organic solvent. As an organic solvent, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP) , 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol, etc. I can. Two or more of these solvents may be used in combination, and further, aromatic hydrocarbons such as xylene and toluene may be used in combination. Although it does not specifically limit as content of an organic solvent, It is preferable to use it by adjusting it to an amount used so that the concentration of polyamic acid or polyimide is about 5 to 30 weight%.

Moreover, the resin composition of this embodiment may contain inorganic fillers other than the spherical silica particle provided with the said conditions a-c, and organic fillers, as needed, as long as the effect of the invention is not impaired. Specifically, for example, silica particles not provided with the above conditions a to c, inorganic fillers such as aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and fluorine-based polymer particles And organic fillers such as liquid crystal polymer particles. These can be used alone or in combination of two or more. Further, if necessary, a plasticizer, a curing accelerator, a coupling agent, a filler, a pigment, a flame retardant, and the like can be appropriately blended as other optional components.

<Viscosity>

The viscosity of the resin composition is a viscosity range in which it is easy to form a coating film having a uniform thickness by increasing the handling properties when coating the resin composition particles.For example, the viscosity is preferably in the range of 5000 cps to 100000 cps, and is preferably in the range of 10000 cps to 50000 cps. It is more preferable to fall within the range. If the viscosity is out of the above range, defects such as uneven thickness and streaks tend to occur in the film during a coating operation with a coater or the like.

<Preparation of resin composition>

When preparing the resin composition, for example, spherical silica particles may be directly blended into a resin solution of polyamic acid. Alternatively, in consideration of the dispersibility of the filler, spherical silica particles are previously mixed in a reaction solvent in which either one of the acid dianhydride component and the diamine component, which are the raw materials of the polyamic acid, are added, and then the other raw material is added under stirring. You may advance polymerization. In either method, the whole amount of spherical silica particles may be added at once, or may be added little by little by dividing into several times. In addition, the raw materials may also be put in batch, or may be divided into several times and mixed little by little.

[Resin film]

The resin film of the present embodiment is a resin film having a single layer or a plurality of polyimide layers, and at least one of the polyimide layers may be a spherical silica-containing polyimide layer containing a cured product of the resin composition.

Among the resin films, the thickness of the spherical silica-containing polyimide layer formed from the resin composition is preferably in the range of 5 to 150 µm, and more preferably in the range of 45 to 100 µm. _{In addition, it is preferable that the particle diameter D 100} of the spherical silica particles is in the range of 0.05 to 0.7 with respect to the thickness of the spherical silica-containing polyimide layer. _{When the particle diameter D 100} of the spherical silica particles is less than 0.05 to the thickness of the spherical silica-containing polyimide layer, the effect of improving dielectric properties may be insufficient, and when it exceeds 0.7, the spherical silica-containing polyimide layer The smoothness of the surface of is impaired, and when a resin film is formed, the bendability may fall.

The thickness of the entire resin film is preferably in the range of 5 to 150 µm, and more preferably in the range of 45 to 80 µm. If the thickness of the resin film is less than 5 µm, problems such as wrinkles are likely to occur in the metal foil in the conveyance process during the manufacture of the metal-clad laminate. Conversely, when the thickness of the resin film exceeds 100 µm, it tends to be disadvantageous in terms of lowering the bendability of the resin film.

In addition, it is preferable that the ratio of the thickness of the spherical silica-containing polyimide layer to the overall thickness of the resin film is 50% or more. If the ratio of the thickness of the spherical silica-containing polyimide layer to the total thickness of the resin film is less than 50%, the effect of improving the dielectric properties cannot be sufficiently obtained.

The method of forming the spherical silica-containing polyimide layer is not particularly limited, and a known method can be employed. Here, the most representative example is shown.

First, a resin composition is directly cast onto an arbitrary supporting substrate to form a coating film. Next, the coating film is dried and removed from the solvent to some extent at a temperature of 150°C or less. When the resin composition contains polyamic acid, after that, the coating film is further subjected to heat treatment for about 5 to 30 minutes at a temperature range of 100 to 400°C, preferably 130 to 360°C for imidization. . In this way, a spherical silica-containing polyimide layer can be formed on the supporting substrate. In the case of using two or more polyimide layers, a resin solution of a first polyamic acid is applied and dried, and then a resin solution of a second polyamic acid is applied and dried. Thereafter, in the same manner, a resin solution of a third polyamic acid, then a resin solution of a fourth polyamic acid, etc., a resin solution of a polyamic acid is sequentially applied as many times as necessary, followed by drying. do. After that, it is preferable to perform imidization by performing heat treatment for about 5 to 30 minutes at a temperature range of 100 to 400°C. If the heat treatment temperature is lower than 100°C, the dehydration ring closure reaction of the polyimide does not proceed sufficiently, whereas if it exceeds 400°C, the polyimide layer may be deteriorated.

Further, another example of forming the spherical silica-containing polyimide layer will be given.

First, on an arbitrary supporting substrate, a resin composition is cast and formed into a film. This film-like molded article is heated and dried on a supporting substrate to obtain a gel film having self-supporting properties. After peeling the gel film from the supporting substrate, when the resin composition contains a polyamic acid, it is subjected to heat treatment at a higher temperature and imidized to obtain a polyimide resin film.

The supporting base material used for formation of the spherical silica-containing polyimide layer is not particularly limited, and a base material of any material may be used. In addition, at the time of formation of a resin film, it is not necessary to form the resin film in which imidization was completed completely on the support base material. For example, the resin film in the state of a polyimide precursor in a semi-cured state may be separated from the supporting substrate by means such as peeling, and the imidization may be completed after separation to obtain a resin film.

The resin film may contain only a polyimide layer containing an inorganic filler such as spherical silica particles (including the spherical silica-containing polyimide layer), or may have a polyimide layer not containing an inorganic filler. In the case where the resin film has a multi-layered structure, in consideration of improvement in dielectric properties, it is preferable to contain inorganic fillers in all of the layers. However, by making the adjacent layer of the polyimide layer containing the inorganic filler a layer that does not contain an inorganic filler or a layer with a low content thereof, it is an advantageous effect that sliding of the inorganic filler, such as during processing, can be prevented. You can have. In the case of having a polyimide layer not containing an inorganic filler, the thickness thereof is, for example, within the range of 1/100 to 1/2, preferably 1/20 to 1/3 of the polyimide layer containing the inorganic filler. It is better to be within the range of. In the case of having a polyimide layer that does not contain an inorganic filler, when the polyimide layer is brought into contact with the metal layer, the adhesion between the metal layer and the insulating resin layer is improved.

Coefficient of thermal expansion (CTE) of the resin film is not particularly limited, for example, 5 × 10 ^-6 to 40 × 10 ^-6 / K (5 to 40ppm / K), and preferably, 10 × 10 in the range of ^{- It} is more preferable within the range of 6 to 35×10 ^-6 /K (10 to 35 ppm/K). When the coefficient of thermal expansion of the resin film ^{is less than 5×10 −6} /K, curling is likely to occur after setting it as a metal-clad laminate, and handling property is inferior. On the other hand, when the coefficient of thermal expansion of the resin film ^{exceeds 40 × 10 -6} /K, the dimensional stability as an electronic material such as a flexible substrate is inferior, and heat resistance tends to decrease.

<genetic tangent>

When the resin film is applied as an insulating resin layer of a circuit board, for example, in order to reduce dielectric loss during transmission of high-frequency signals, the whole film is measured by a split post dielectric resonator (SPDR). It is preferable that it is 0.005 or less, and, as for the dielectric loss tangent (Tan δ) in 10 GHz of, it is more preferable that it is 0.004 or less. In order to improve the transmission loss of the circuit board, it is particularly important to control the dielectric loss tangent of the insulating resin layer, and by making the dielectric loss tangent within the above range, the effect of lowering the transmission loss is increased. Therefore, when a resin film is applied as an insulating resin layer of a high frequency circuit board, for example, transmission loss can be efficiently reduced. When the dielectric loss tangent at 10 GHz exceeds 0.005, when a resin film is applied as an insulating resin layer of a circuit board, problems such as an increase in electric signal loss on a transmission path of a high frequency signal are liable to occur. Although the lower limit of the dielectric loss tangent in 10 GHz is not particularly limited, it is necessary to consider the control of physical properties when a resin film is applied as an insulating resin layer of a circuit board.

<Relative permittivity>

When the resin film is applied as an insulating resin layer of a circuit board, for example, in order to ensure impedance matching, it is preferable that the relative dielectric constant in the film as a whole is 4.0 or less in 3 to 20 GHz. If the relative dielectric constant in 3 to 20 GHz exceeds 4.0, when a resin film is applied as an insulating resin layer of a circuit board, it leads to deterioration of dielectric loss, and the loss of electric signals on the transmission path of high frequency signals increases. Problems become more prone to occur.

<Metal Clad Laminate>

The metal-clad laminate of the present embodiment is a metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one side of the insulating resin layer, and at least one layer of the insulating resin layer contains the resin film. The metal-clad laminate may be a single-sided metal-clad laminate having a metal layer only on one side of the insulating resin layer, or a double-sided metal-clad laminate having metal layers on both sides of the insulating resin layer.

The metal-clad laminate of the present embodiment does not exclude the use of an adhesive for bonding the polyimide layer containing the inorganic filler and the metal foil. However, in the case of interposing an adhesive layer in a double-sided metal-clad laminate having metal layers on both sides of the insulating resin layer, the thickness of the adhesive layer is preferably less than 30% of the thickness of the entire insulating resin layer so as not to impair the dielectric properties. And more preferably less than 20%. In addition, in the case of interposing an adhesive layer in a single-sided metal-clad laminate having a metal layer only on one side of the insulating resin layer, the thickness of the adhesive layer is preferably less than 15% of the thickness of the entire insulating resin layer so as not to impair the dielectric properties. And more preferably less than 10%. In addition, since the adhesive layer constitutes a part of the insulating resin layer, it is preferably a polyimide layer. From the viewpoint of imparting heat resistance, the glass transition temperature of the polyimide, which is the main material of the insulating resin layer, is preferably set to 300°C or higher. To set the glass transition temperature to 300°C or higher, it becomes possible by appropriately selecting the above-described acid dianhydride or diamine component constituting the polyimide.

As a method of manufacturing a metal-clad laminate using a resin film as an insulating resin layer, for example, a metal layer on a resin film by heat-pressing a metal foil directly on the resin film or through an optional adhesive, or by a method such as metal vapor deposition. A method of forming, etc. are mentioned. In addition, the double-sided metal-clad laminate is, for example, a method of forming a single-sided metal-clad laminate, and then making the polyimide layers face each other and pressing by hot pressing, or applying a metal foil to the polyimide layer of the single-sided metal-clad laminate. It can be obtained by a method of forming by pressing or the like.

<Metal layer>

The material of the metal layer is not particularly limited, but, for example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, and alloys thereof And the like. Among these, copper or a copper alloy is particularly preferable. The metal layer may include a metal foil, or may be formed by metal vapor deposition on a film. In addition, since a resin composition can be applied directly, a metal foil or a metal plate can be used, and a copper foil or a copper plate is preferable.

The thickness of the metal layer is not particularly limited because it is appropriately set according to the purpose of use of the metal-clad laminate, but is preferably in the range of 5 µm to 3 mm, and more preferably in the range of 12 µm to 1 mm. If the thickness of the metal layer is less than 5 µm, there is a concern that problems such as wrinkles may occur during transport in the manufacture of a metal-clad laminate or the like. Conversely, if the thickness of the metal layer exceeds 3 mm, it is hard and workability deteriorates. As for the thickness of the metal layer, generally, a thick one is suitable for applications such as a vehicle-mounted circuit board, and a thin metal layer is suitable for applications such as an LED circuit board.

Example

Hereinafter, examples are shown, and the features of the present invention will be described in more detail. However, the scope of the present invention is not limited to the examples. In addition, in the following examples, various measurements and evaluations are as follows, unless otherwise specified.

[Measurement of viscosity]

The viscosity of the resin solution was measured at 25°C using an E-type viscometer (manufactured by Brookfield, brand name; DV-II+Pro). The rotational speed was set so that the torque became 10% to 90%, and 1 minute after the measurement was started, the value when the viscosity stabilized was read.

[Measurement of relative permittivity and dielectric loss tangent]

<Silica particles>

Using a dielectric constant measuring device manufactured by Kanto Denshi Oyo Kaihatsu Co., Ltd. by a cavity resonator perturbation method, the dielectric constant measuring mode; It was set to TM101, and the relative dielectric constant (ε1) and dielectric loss tangent (Tanδ1) of the silica particles at a frequency of 10 GHz were measured. In addition, the inner diameter of the sample tube tube is 1.68 mm, the outer diameter is 2.8 mm, and the height is 8 cm.

<resin film>

The relative dielectric constant and dielectric loss tangent are the relative dielectric constant (ε1) of the resin film (resin film after curing) at a frequency of 10 GHz using a vector network analyzer (manufactured by Agilent, brand name; Vector Network Analyzer E8363C) and an SPDR resonator. The dielectric loss tangent (Tanδ1) was measured. In addition, the resin film used for measurement is temperature; 24 to 26°C, humidity; It left to stand for 24 hours under the conditions of 45-55%.

[Measurement method of linear thermal expansion coefficient (CTE)]

A resin film having a size of 3 mm x 20 mm was heated from 30° C. to 265° C. at a constant heating rate while applying a load of 5.0 g using a thermomechanical analyzer (manufactured by Bruker, brand name: 4000SA), and further After holding at the temperature for 10 minutes, it was cooled at a rate of 5°C/min, and the average coefficient of thermal expansion (coefficient of thermal expansion) from 200°C to 100°C was calculated.

[Measurement method of particle diameter]

Using a laser diffraction type particle size distribution measuring apparatus (manufactured by Malvern, brand name: Master Sizer 3000), the particle diameter was measured by a laser diffraction/scattering type measurement method.

[Measurement method of true specific gravity]

It was measured by the pycnometer method (liquid substitution method) using a continuous automatic powder true density measuring apparatus (made by Seishin Engineering Co., Ltd., brand name; AUTO TRUE DENSERMAT-7000).

[Evaluation of bendability]

According to JISK5600-1, the center of the long side of a 5cm×10cm sized resin film is evenly bent over 1 to 2 seconds as if winding it around a 5mmφ metal rod, and even if the resin film is bent 180°, it is broken or cracked. What did not generate|occur|produce was made into "good", and a break or crack was made into "impossible".

The abbreviations used in Synthesis Examples, Comparative Examples, and Examples represent the following compounds.

PMDA: pyromellitic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

BAPP: 2,2-bis[4-(4-aminophenoxy)phenyl]propane

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

DMAc: N,N-dimethylacetamide

Filler 1: manufactured by Nittetsu Chemical & Materials Co., Ltd., a brand name; CR10-20 (spherical cristobalite silica powder, true sphere, silica content; 99.4 wt%, cristobalite phase; 98 wt%, true specific gravity; 2.33, specific surface area; 0.63 m 2 /g, D ₅₀ ; 10.8 µm, D ₉₀ ; 16.4 µm , D ₁₀₀ ; 24.1 μm, the particle diameter of the maximum frequency F1; 11.2 μm, the maximum frequency F1; 10.6%, the particle diameter of the maximum frequency F2; 1.0 μm, the maximum frequency F2; 1.4%, F1/F2; at 11.2, 10 GHz Relative dielectric constant; 3.16, dielectric loss tangent at 10 GHz; 0.0008)

Filler 2: manufactured by Nittetsu Chemical & Materials, a brand name; SC70-2 (spherical amorphous silica powder, true sphere, silica content; 99.9% by weight, true specific gravity; 2.33, specific surface area; 1.1 m2/g, D ₅₀ ; 11.7 μm, D ₉₀ ; 16.4 μm, D ₁₀₀ ; 24.1 μm, Particle diameter of maximum frequency F1; 11.2 µm, maximum frequency F1; 10.8%, particle diameter of maximum frequency F2; 1.5 µm, maximum frequency F2; 1.2%, F1/F2; 7.5, relative dielectric constant at 10 GHz; 3.08, 10 GHz Dielectric loss tangent in; 0.0015)

Filler 3: manufactured by Nittetsu Chemical & Materials Co., Ltd., a brand name; SP40-10 (spherical amorphous silica powder, true sphere, silica content; 99.9% by weight, true specific gravity; 2.21, specific surface area; 8.6 _{m 2 /g, D 50} ; 2.5 _{µm, D 90} ; 3.6 _{µm, D 100} ; 7.0 µm, The particle diameter of the maximum frequency value F1; 2.2 µm, the maximum frequency value F1; 9.0%, the particle diameter of the maximum frequency value F2; 0.9 占퐉, the maximum frequency value F2; 4.3%, F1/F2; The relative dielectric constant at 2.4 and 10 GHz; 2.78, 10 GHz Dielectric loss tangent in; 0.0030)

(Synthesis Example 1)

To a 300 ml separable flask, 21.65 g of m-TB (101.66 mmol) and 255 g of DMAc were added, followed by stirring at room temperature under a nitrogen stream. After completely dissolving, 17.46 g of PMDA (80.03 mmol) and 5.90 g of BPDA (20.01 mmol) were added, followed by stirring at room temperature for 18 hours to obtain a polyamic acid solution A (solid content: 15%). The viscosity of the obtained polyamic acid solution A was 22,400 cps.

(Synthesis Example 2)

To a 300 ml separable flask, 29.21 g of BAPP (71.15 mmol) and 255 g of DMAc were added, followed by stirring at room temperature under a nitrogen stream. After completely dissolving, 14.74 g of PMDA (67.60 mmol) and 1.05 g of BPDA (3.56 mmol) were added, followed by stirring at room temperature for 18 hours to obtain a polyamic acid solution B. The viscosity of the obtained polyamic acid solution B (solid content concentration: 15%) was 21,074 cps.

[Example 1]

70.0 g of polyamic acid solution A and 7.8 g of filler 1 were mixed and stirred until a visually homogeneous solution was obtained, and polyamic acid solution 1 (viscosity; 24,800 cps, content of filler to polyamic acid) ; 32.6 vol%) was prepared.

The polyamic acid solution 1 was applied on the copper foil 1 (electrolytic copper foil, thickness: 12 µm), and dried at 130°C for 3 minutes. Thereafter, heat treatment was performed in stages from 155°C to 360°C to imidize to prepare a metal-clad laminate 1.

The copper foil of the metal-clad laminate 1 was etched away, and a resin film 1 was prepared. Resin film 1 (thickness: 46.1 µm) had a relative dielectric constant of 2.78, a dielectric loss tangent of 0.0037, a CTE of 34 ppm/K, and a good bendability. Table 1 shows the evaluation results of the resin film 1.

[Example 2]

60.0 g of polyamic acid solution A and 20.0 g of filler 1 were mixed and stirred until a homogeneous solution was visually observed, and polyamic acid solution 2 (viscosity; 28,400 cps, content of filler to polyamic acid) ; 59.2 vol%) was prepared.

In the same manner as in Example 1, a metal-clad laminate 2 and a resin film 2 were prepared. Resin film 2 (thickness: 78.1 µm) had a relative dielectric constant of 2.71, a dielectric loss tangent of 0.0028, a CTE of 34 ppm/K, and a good bendability. Table 1 shows the evaluation results of the resin film 2.

[Example 3]

58.7 g of polyamic acid solution B and 6.1 g of filler 1 were mixed, and stirred until a homogeneous solution was visually observed, and the content of polyamic acid solution 3 (viscosity; 23,000 cps, filler to polyamic acid) ; 30.0 vol%) was prepared.

In the same manner as in Example 1, a metal-clad laminate 3 and a resin film 3 were prepared. The dielectric constant of the resin film 3 (thickness: 51.6 µm) was 3.04, the dielectric loss tangent was 0.0044, and the bendability was good. Table 1 shows the evaluation results of the resin film 3.

[Example 4]

70.0 g of polyamic acid solution A and 7.8 g of filler 2 were mixed and stirred until a visually homogeneous solution was obtained, and polyamic acid solution 4 (viscosity; 23,600 cps, content of filler to polyamic acid) ; 33.8 vol%) was prepared.

In the same manner as in Example 1, a metal-clad laminate 4 and a resin film 4 were prepared. Resin film 4 (thickness: 50.4 µm) had a relative dielectric constant of 2.84, a dielectric loss tangent of 0.0038, a CTE of 28.2 ppm/K, and a good bendability. Table 1 shows the evaluation results of the resin film 4.

[Example 5]

60.0 g of polyamic acid solution A and 20.0 g of filler 2 were mixed and stirred until a homogeneous solution was visually observed, and the content of polyamic acid solution 5 (viscosity; 30,100 cps, filler to polyamic acid) ; 60.5 vol%) was prepared.

In the same manner as in Example 1, a metal-clad laminate 5 and a resin film 5 were prepared. Resin film 5 (thickness: 79.3 µm) had a relative dielectric constant of 2.75, a dielectric loss tangent of 0.0028, a CTE of 20.4 ppm/K, and a good bendability. Table 1 shows the evaluation results of the resin film 5.

[Example 6]

56.2 g of polyamic acid solution B and 5.5 g of filler 2 were mixed and stirred until a visually homogeneous solution was obtained, and polyamic acid solution 6 (viscosity; 23,600 cps, content of filler to polyamic acid) ; 30.0 vol%) was prepared.

In the same manner as in Example 1, a metal-clad laminate 6 and a resin film 6 were prepared. Resin film 6 (thickness: 50.7 µm) had a relative dielectric constant of 3.04, a dielectric loss tangent of 0.0047, and a good bendability. Table 1 shows the evaluation results of the resin film 6.

(Comparative Example 1)

70.0 g of polyamic acid solution A was applied on the copper foil 1, and dried at 130°C for 3 minutes. After that, a stepwise heat treatment was performed from 155°C to 360°C to imidize, thereby preparing a metal-clad laminate 7.

In the same manner as in Example 1, the copper foil of the metal-clad laminate 7 was removed by etching to prepare a resin film 7. Resin film 7 (thickness: 26.7 µm) had a dielectric constant of 3.13, a dielectric loss tangent of 0.0056, a CTE of 21.3 ppm/K, and a good bendability. Table 2 shows the evaluation results of the resin film 7.

(Comparative Example 2)

60.0 g of polyamic acid solution B was applied on the copper foil 1, and dried at 90°C for 1 minute and 130°C for 5 minutes. After that, a stepwise heat treatment was performed from 155°C to 360°C to imidize, thereby preparing a metal-clad laminate 8.

In the same manner as in Example 1, the copper foil of the metal-clad laminate 8 was removed by etching to prepare a resin film 8. Resin film 8 (thickness: 41.4 µm) had a dielectric constant of 3.16, a dielectric loss tangent of 0.0062, a CTE of 51.3 ppm/K, and a good bendability. Table 2 shows the evaluation results of the resin film 8.

(Reference Example 1)

Polyamic acid solution 9 was prepared in the same manner as in Example 1 except that 55.0 g of polyamic acid solution A and 36.3 g of filler 1 were mixed.

The polyamic acid solution 9 was applied on the copper foil 1, and the metal-clad laminate 9 was prepared in the same manner as in Example 1, and then a resin film 9 was prepared. Resin film 9 (thickness: 117.8 µm) had a relative dielectric constant of 2.56, a dielectric loss tangent of 0.0015, and a CTE of 31 ppm/K, and the bendability was impossible. Table 3 shows the evaluation results of the resin film 9.

(Reference Example 2)

A polyamic acid solution 10 was prepared in the same manner as in Example 1 except that 55.6 g of polyamic acid solution A and 36.3 g of filler 2 were mixed.

The polyamic acid solution 10 was applied on the copper foil 1, and it carried out similarly to Example 1, and after preparing the metal-clad laminated board 10, the resin film 10 was prepared. The resin film 10 (thickness: 116.7 µm) had a relative dielectric constant of 2.75, a dielectric loss tangent of 0.0018, and a CTE of 13 ppm/K, and the bendability was impossible. Table 3 shows the evaluation results of the resin film 10.

(Reference Example 3)

Polyamic acid solution 11 was prepared in the same manner as in Example 1 except that 56.2 g of polyamic acid solution B and 5.5 g of filler 3 were mixed.

The polyamic acid solution 11 was applied on the copper foil 1, and it carried out similarly to Example 1, and after preparing the metal-clad laminated board 11, the resin film 11 was prepared. Resin film 11 (thickness: 45.6 µm) had a relative dielectric constant of 3.25, a dielectric loss tangent of 0.0052, a CTE of 40.9, and a good bendability. Table 3 shows the evaluation results of the resin film 11.

The polyimide films containing spherical silica particles having an average particle diameter D ₅₀ of 10 μm or more of Examples 1 to 6 were compared with the polyimide films not containing silica of Comparative Examples 1 and 2, and the dielectric constant and dielectric loss tangent were lowered. have.

In addition, the polyimide films of Reference Examples 1 and 2 containing 70% by volume or more of spherical silica particles had deteriorated bendability compared to the examples.

Further, the polyimide film of Reference Example 3 in which spherical silica particles having an average particle diameter D ₅₀ of 2.5 µm and small were blended had higher dielectric constants and dielectric loss tangents than those of Examples, and had a small effect of improving dielectric properties.

As described above, embodiments of the present invention have been described in detail for purposes of illustration, but the present invention is not limited to the above embodiments, and various modifications are possible.

Claims (7)

It is a resin composition containing polyamic acid or polyimide and spherical silica particles,
The frequency distribution curve of the spherical silica particles obtained by measurement of a volume-based particle size distribution by a laser diffraction scattering method includes the following conditions a to c;
_{a) the average particle diameter D 50} at which the cumulative value is 50% is in the range of 9.0 to 12.0 µm;
_{b) the particle diameter D 90} at which the cumulative value is 90% is in the range of 15 to 20 μm;
_{c) The particle diameter D 100} at which the cumulative value is 100% is 25 µm or less;
And the content of the spherical silica particles is within a range of 20 to 65% by volume with respect to the polyamic acid or the polyimide. The method of claim 1,
The spherical silica particles are further subjected to the following condition d;
d) having a frequency maximum value F1 and a frequency maximum value F2, wherein the F1 is in a region of 9.0 to 14.0 µm, and the F2 is in a region of 0.5 to 3.0 µm;
A resin composition characterized in that it satisfies. The method according to claim 1 or 2,
The spherical silica particles are further subjected to the following condition e;
e) having a frequency maximum value F1 and a frequency maximum value F2, and the ratio (F1/F2) of F1 and F2 is in the range of 3 to 28;
A resin composition characterized in that it satisfies. It is a resin film having a single layer or a plurality of polyimide layers,
At least one of the polyimide layers is a spherical silica-containing polyimide layer comprising a cured product of the resin composition according to any one of claims 1 to 3, and the thickness of the spherical silica-containing polyimide layer is 5 A resin film, characterized in that in the range of to 150㎛. The method of claim 4,
_{A resin film, wherein the particle diameter D 100} of the spherical silica particles is within a range of 0.05 to 0.7 with respect to the thickness of the spherical silica-containing polyimide layer. The method according to claim 4 or 5,
The resin film, wherein the thickness is in the range of 5 to 150 µm, and the ratio of the thickness of the spherical silica-containing polyimide layer is 50% or more. A metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one side of the insulating resin layer,
A metal-clad laminate, wherein the insulating resin layer contains the resin film according to any one of claims 4 to 6.