Resin composition and electronic component

Abstract

A resin composition, a molded body of which is an electromagnetic wave absorber, the resin composition being such that an imaginary part (ε") of the complex dielectric constant at 25°C and 10 GHz and the volume resistivity (ρv) at 25°C in the molded body satisfy formula (1), and the imaginary part (ε") is greater than 1.25.　Formula (1): 20<(log ρv)×ε"<600

Description

[Technical Field]

[0001] The present disclosure relates to a resin composition and an electronic component having an electromagnetic wave absorbing function. [Background technology]

[0002] In recent years, electronic devices have been required to operate at even higher speeds, and the operating frequencies of ICs (Integrated Circuits) such as memories, CPUs (Central Processing Units), PMICs (Power Management Integrated Circuits), and Bluetooth (registered trademark) modules have been rising rapidly, resulting in the emission of high-frequency electromagnetic noise from these ICs. Demands for large-volume and high-speed transmission in the information and communications field are becoming increasingly strict, and in order to meet these demands, both operating frequencies and carrier frequencies must be made higher.

[0003] On the other hand, to ensure the transmission reliability of communication devices, it is necessary to prevent electromagnetic interference. For example, electromagnetic wave shielding materials equipped with a metal shielding layer are known as a method for suppressing electromagnetic noise. For example, Patent Document 1 proposes an electromagnetic wave shielding material formed by dispersing soft magnetic metal powder, such as powder of a metal selected from Fe, Ni, Co, and V or an alloy consisting of two or more of these metals, in a rubber or plastic matrix and molding the resulting material into a sheet. Patent Document 2 also proposes a sheet-shaped radio wave absorber in which a radio wave absorbing layer formed from a radio wave absorbing material comprising silicon carbide powder dispersed in a matrix resin is laminated on the surface of a metal body. Furthermore, Patent Document 3 proposes an electromagnetic wave absorbing sheet for the 5 to 7 GHz frequency band, which includes a dielectric layer made of a matrix containing a carbon material, a divided conductive film layer laminated on one side of the dielectric layer, and an electromagnetic wave reflecting layer laminated on the other side of the dielectric layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-68889 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-57093 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-209515 Summary of the Invention

[0005] The present disclosure was completed based on this finding.

[0006] That is, the present disclosure relates to the following: [1] The resin composition of the present disclosure is a resin composition in which a molded body of the resin composition is an electromagnetic wave absorber, and the imaginary part (ε'') of the complex permittivity of the molded body at 25°C and 10 GHz and the volume resistivity (ρv) at 25°C satisfy the following formula (1), and the imaginary part (ε'') is greater than 1.25: 20<(log ρv)×ε′′<600 (1) [2] The electronic component of the present disclosure includes a molded article made of the resin composition described in [1] above. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view illustrating an electronic component according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] Among electromagnetic wave absorbers, those that use magnetic materials have a low complex permeability in the GHz-order high frequency bands above 5 GHz and below 100 GHz, and are therefore not effective enough in suppressing electromagnetic noise. In addition, those that use reflection by metals cannot avoid so-called self-poisoning. The resin composition of the present disclosure can give a molded article that has excellent electromagnetic wave absorption performance in the high frequency band.

[0009] Hereinafter, the present disclosure will be described in detail with reference to an embodiment. The resin composition of the present disclosure is an electromagnetic wave absorber when a molded article of the resin composition is formed, and the imaginary part (ε'') of the complex permittivity at 25°C and 10 GHz and the volume resistivity (ρv) at 25°C of the molded article satisfy the following formula (1): In addition, the imaginary part (ε'') is greater than 1.25. 20<(log ρv)×ε′′<600 (1)

[0010] When absorbing high-frequency electromagnetic waves by the dielectric loss of a molded body, it is necessary to increase the imaginary part (ε'') of the complex dielectric constant of the molded body. On the other hand, the ε'' corresponds to the resistance component in alternating current, and a material with a large ε'' generally has a low resistance in direct current. Since the molded body is also required to have electrical insulation performance, it is necessary to increase the direct current resistance of the molded body. The inventors have found that by making the imaginary part (ε'') of the complex dielectric constant at 25°C and 10 GHz and the volume resistivity (ρv) at 25°C of the molded body satisfy the above formula (1), it is possible to increase the direct current resistance of the molded body and improve the electromagnetic wave absorption performance in the high-frequency band.

[0011] The product of the imaginary part (ε") of the complex dielectric constant of the molded article and the logarithm of the volume resistivity (ρv) is greater than 20. When the product of ε" and the logarithm of ρv is greater than 20, the electromagnetic wave absorption performance or electrical insulation in the high frequency band is sufficient. From this perspective, depending on the application, the product of ε" and the logarithm of ρv may be 30 or more, 40 or more, or 45 or more. There is no particular upper limit to the product of ε" and the logarithm of ρv, but it is determined by the upper limit of ε" and ρv. The upper limit of the product of ε" and the logarithm of ρv may be less than 600. When the product of ε" and the logarithm of ρv is 600 or more, signal loss may increase. From this perspective, the product of ε" and the logarithm of ρv may be 300 or less, 100 or less, or 80 or less.

[0012] The ε" is greater than 1.25. If the ε" is 1.25 or less, the electromagnetic wave absorption ability of the molded article in the high frequency band may be reduced. From this viewpoint, the ε" may be 3 or more, 4 or more, 5 or more, or 6 or more. On the other hand, the upper limit of the ε" may be less than 40, or may be 35 or less.

[0013] From the viewpoint of reducing signal loss, the molded article may have a real part of complex dielectric constant (ε') at 25°C and 10 GHz of less than 40, less than 30, or less than 25. There is no particular lower limit for ε', but it may be greater than 1.25. The ε′ and ε″ can be measured by a waveguide method, specifically by the method described in the examples.

[0014] The dielectric loss tangent (tan δ) of the molded article at 25° C. and 10 GHz may be 0.1 or more and 0.8 or less, or 0.2 or more and 0.75 or less, from the viewpoint of reducing electromagnetic wave signal loss.

[0015] The volume resistivity (ρv) of the molded body at 25°C is 1.0 × 10 6 It may be 1.0×10 Ωcm or more. 7 There is no particular upper limit, but it is 1.0 × 10 16 It may be Ωcm or less. The ρv can be measured in accordance with JIS K-6911:2006, specifically by the method described in the examples.

[0016] The molded article may have a low specific gravity in consideration of its application to portable devices and in-vehicle devices, which require lightweight construction. The specific gravity of the molded article may be 1.2 or more and 3.2 or less, or 1.5 or more and 3.0 or less. The specific gravity of the molded body can be determined by measuring the mass and buoyancy of the cured material in air and water using a balance. Specifically, it can be measured by the method described in the examples.

[0017] Some electronic components for communications generate a large amount of heat, generally requiring a heat dissipation mechanism that incorporates a heat dissipation sheet or the like. In particular, even greater heat dissipation capabilities will be required in future high-frequency bands. Increasing the thermal conductivity of the molded body to impart heat dissipation properties to the electromagnetic wave absorbing material would eliminate the need for other mechanisms, such as a heat dissipation sheet, and would be extremely useful because it would not only reduce the size and weight of electronic components but also reduce assembly labor. From this perspective, the thermal conductivity of the molded body may be 0.5 W / m·K or more and 6.0 W / m·K or less, or 0.6 W / m·K or more and 5.0 W / m·K or less. The thermal conductivity of the molded body can be determined by a hot wire method in which the temperature gradient when heat flow energy is applied by a hot wire is determined by comparing it with a sample having a known thermal conductivity, or a laser flash method in which high energy is instantaneously applied to a homogeneous material by a laser or the like, and the thermal conductivity is calculated based on the thermal diffusivity and specific heat measured at that time. Specifically, it can be measured by the method described in the examples.

[0018] Electronic components for communication are becoming smaller and lighter, and so thin electromagnetic wave absorbers are required. For example, some modular electronic component packages are asymmetrically thin and large in area. In packaging processes such as FOWLP (Fan Out Wafer Level Package), in which electronic components on large substrates are encapsulated on one side and then separated into individual pieces, it is necessary to reduce warpage. It is useful to make the thermal expansion of the molded body as close as possible to that of an insert with a low thermal expansion coefficient, that is, to reduce the thermal expansion of the molded body. From this perspective, the thermal expansion coefficient of the molded body (α1: thermal expansion coefficient from room temperature (25°C) to the glass transition temperature) may be 1 ppm / deg. or more, or 3 ppm / deg. or more. Furthermore, the thermal expansion coefficient of the molded body may be 40 ppm / deg. or less, or 35 ppm / deg. or less. When the molded body is used as a sealing material, the thermal expansion coefficient of the molded body may be 18 ppm / deg. or less, or 15 ppm / deg. or less. The thermal expansion coefficient of the molded body can be determined from the slope of the tangent line between 25 and 60°C in a TMA chart obtained by measurement using thermal mechanical analysis (TMA), and specifically, can be measured by the method described in the examples.

[0019] The resin composition of the present disclosure is not particularly limited as long as the resulting molded article satisfies the above formula (1), but may contain (A) at least one resin selected from a thermosetting resin and a thermoplastic resin, (B) an inorganic filler (excluding component (C)), and (C) a carbon material.

[0020] [(A) Resin] The resin of component (A) is at least one selected from thermosetting resins and thermoplastic resins. Examples of thermosetting resins include epoxy resins, phenolic resins, and imide resins. Examples of thermoplastic resins include polyamides and polycarbonates. The resin of component (A) may be a thermosetting resin from the viewpoint of viscosity in precision part molding, or may be an epoxy resin or an imide resin from the viewpoints of electrical insulation and heat resistance. The resin of the component (A) may be used alone or in combination of two or more.

[0021] The resin of component (A) may have a high imaginary part (ε'') of the complex dielectric constant at 25°C and 10 GHz. When the resin of component (A) has a high ε'', the molded article is more likely to satisfy formula (1). Furthermore, the ε'' of the molded article at 25°C and 10 GHz can be made larger than 1.25. The ε'' of the resin of component (A) may be 0.04 or more and 2.0 or less, 0.05 or more and 2.0 or less, or 0.1 or more and 1.0 or less. Furthermore, the resin of component (A) may have a low real part (ε') of the complex dielectric constant at 25°C and 10 GHz. When the resin of component (A) has a low ε', the molded article can have an ε' of less than 40 at 25°C and 10 GHz. The ε' of the resin of component (A) may be 2.0 or more and 5.0 or less. The ε′ and ε″ of the resin of component (A) are values ​​measured by a waveguide method after molding a test piece plate together with a curing agent, specifically, values ​​measured by the method described in the examples.

[0022] The epoxy resin has two or more epoxy groups in one molecule and is not particularly limited in terms of molecular structure, molecular weight, etc., as long as it is one that is commonly used in electronic components. Examples of the epoxy resin include aliphatic epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, and dicyclopentadiene derivatives; and aromatic epoxy resins such as biphenyl, biphenyl aralkyl, naphthyl, and bisphenol types. These epoxy resins may be used alone or in combination. There are no particular limitations on their state, and they may be liquid or solid at room temperature (25°C). For example, the epoxy resin may be a liquid bisphenol epoxy resin, specifically bisphenol A and bisphenol F. The liquid bisphenol epoxy resin may be a liquid bisphenol A epoxy resin. Liquid bisphenol A epoxy resins are commercially available, such as Epomic (registered trademark) R140 (manufactured by Mitsui Chemicals, Inc.). In the present disclosure, the liquid bisphenol epoxy resin refers to a bisphenol epoxy resin that is liquid at 25°C.

[0023] The epoxy equivalent of the epoxy resin may be 140 or more from the viewpoint of thermomechanical properties. Furthermore, from the viewpoint of electromagnetic wave absorption ability, it may be 200 or more, or 250 or more. The upper limit of the epoxy equivalent may be 400 or less, or 380 or less from the viewpoint of thermomechanical properties.

[0024] The epoxy resin is (R 1 O)m and a polyoxyalkylene structure represented by (R 2O)n. When the resin composition of the present disclosure contains an epoxy resin having a polyoxyalkylene structure, the obtained molded article is more likely to satisfy the formula (1). where R 1 and R 2 each independently represents an alkylene group having 1 or more carbon atoms. m+n may be 1 or more and 50 or less, or 1 or more and 20 or less. m may be 0 or more and 49 or less, or 0 or more and 19 or less. n may be 1 or more and 50 or less, or 1 or more and 20 or less.

[0025] R 1 and R 2 Examples of the alkylene group represented by the formula (I) include alkylene groups having 1 to 6 carbon atoms, and specific examples include a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a hexamethylene group, etc. From the viewpoint of electromagnetic wave absorption ability, the alkylene group may be a methylene group or an ethylene group. m R 1 In the O group, multiple R 1 may be the same alkylene group or may be alkylene groups with different carbon numbers. 2 In the O group, multiple R 2 may be the same alkylene group or may be alkylene groups with different carbon numbers.

[0026] Examples of epoxy resins having a polyoxyalkylene structure include liquid epoxy resins having a bisphenol A skeleton, polyethylene glycol diglycidyl ether, etc. A commercially available liquid epoxy resin having a bisphenol A skeleton is Rikaresin BEO-60E (manufactured by New Japan Chemical Co., Ltd.) represented by the following general formula (1), and a commercially available polyethylene glycol diglycidyl ether is Epolite 400E (manufactured by Kyoeisha Chemical Co., Ltd.) containing as its main component a compound represented by the following general formula (2).

[0027] [ka]

[0028] [ka]

[0029] An example of the imide resin is bisallylnadiimide. Bisallylnadiimide is commercially available, such as BANI-M (manufactured by Maruzen Petrochemical Co., Ltd.) and BANI-X (manufactured by Maruzen Petrochemical Co., Ltd.).

[0030] The content of the resin of the component (A) may be 6% by mass or more and 40% by mass or less, 10% by mass or more and 40% by mass or less, 20% by mass or more and 38% by mass or less, or 25% by mass or more and 30% by mass or less, based on the total amount of the resin composition of the present disclosure. When the content of the resin of the component (A) is 10% by mass or more, the composition can have suitable thermomechanical properties, and when it is 40% by mass or less, the composition can maintain appropriate fluidity.

[0031] When the resin of the component (A) contains a thermosetting resin, the resin composition of the present disclosure may further contain a curing agent and a curing accelerator. Examples of the curing agent include aliphatic amines, aromatic amines, dicyandiamide, dihydrazide compounds, acid anhydrides, phenolic resins, etc. These may be used alone or in combination of two or more. Examples of the curing accelerator include organic peroxides such as dicumyl peroxide and dibutyl peroxide, and imidazole compounds such as 2-methylimidazole and 2-ethylimidazole, etc. These may be used alone or in combination of two or more. When the resin composition of the present disclosure contains a curing agent, the content thereof may be 1.0% by mass or more and 20.0% by mass or less, 2.0% by mass or more and 18.0% by mass or less, or 3.0% by mass or more and 15.0% by mass or less, relative to the total amount of the resin composition. Furthermore, when the resin composition of the present disclosure contains a curing accelerator, the content thereof may be 0.1% by mass or more and 10.0% by mass or less, 0.2% by mass or more and 8.0% by mass or less, or 0.5% by mass or more and 6.0% by mass or less, relative to the total amount of the resin composition.

[0032] [(B) Inorganic filler] The inorganic filler of the component (B) (excluding the component (C) described below) is not particularly limited as long as it is used in electronic components, but may be an inorganic filler with a high dielectric constant and a high dielectric loss tangent, such as silica, alumina, titanium oxide, barium titanate, silicon nitride, aluminum nitride, or silicon carbide. These may be used alone or in combination of two or more. From the viewpoint of improving the electromagnetic wave absorption performance of the resulting molded article in the high frequency band, the component (B) may be at least one selected from silica, alumina, and silicon carbide, or may be silicon carbide.

[0033] The inorganic filler of component (B) may have high resistivity and a high imaginary part (ε'') of the complex dielectric constant at 25°C and 10 GHz. When the inorganic filler of component (B) has a high ε'', the molded article is more likely to satisfy formula (1). Furthermore, the ε'' of the molded article at 25°C and 10 GHz can be made larger than 1.25. The ε'' of the inorganic filler of component (B) may be 0.1 or more and 30.0 or less, 1.0 or more and 30.0 or less, 1.5 or more and 20.0 or less, or 2.0 or more and 20.0 or less. The ε'' of the inorganic filler of component (B) is a value measured by a waveguide method after firing a test piece plate, specifically a value measured by the method described in the examples.

[0034] The shape of the inorganic filler of the component (B) is not particularly limited, and examples thereof include powder, spheres, fibers, etc. The shape of the inorganic filler of the component (B) may be powder or spherical.

[0035] The average particle size of the inorganic filler of component (B) is not particularly limited, but may be 0.1 μm to 100 μm, 0.2 μm to 75 μm, or 0.2 μm to 50 μm. Furthermore, the maximum particle size of the inorganic filler of component (B) may be 150 μm or less, or 100 μm or less, considering application to thin-wall molding materials. When the average particle size of the inorganic filler of component (B) is 0.1 μm or more, appropriate fluidity can be maintained, and when it is 100 μm or less, molding defects such as underfilling can be reduced. In this specification, the average particle size refers to the volume average particle size, and the average particle size of the inorganic filler of component (B) can be calculated as the average value of the long diameter of the particles measured using a laser diffraction particle size distribution analyzer.

[0036] When silicon carbide is contained in the inorganic filler of component (B), the content of silicon carbide may be 10 mass% or more, 50 mass% or more, 70 mass% or more, or 100 mass% of the total inorganic filler, from the viewpoint of improving the electromagnetic wave absorption performance of the resulting molded body in the high frequency band.

[0037] The content of the inorganic filler of the component (B) may be 30% by mass or more and 92% by mass or less, 35% by mass or more and 90% by mass or less, or 40% by mass or more and 88% by mass or less, based on the total amount of the resin composition of the present disclosure. When the content of the inorganic filler of the component (B) is 30% by mass or more, the electromagnetic wave absorption performance in the high frequency band of the obtained molded article can be improved, and when it is 92% by mass or less, appropriate fluidity can be obtained.

[0038] [(C) Carbon material] The carbon material of component (C) is not particularly limited as long as it is one used in electronic components, and may be a carbon material that can increase the dielectric constant and loss dielectric constant of the resulting molded article. This allows the resulting molded article to have excellent electromagnetic wave absorption performance in the high frequency band. Furthermore, the molded article is more likely to satisfy formula (1). Examples of carbon materials for component (C) include carbon black, carbon nanotubes, fullerenes, graphite, graphene, and derivatives thereof. These may be used alone or in combination of two or more. The carbon material for component (C) may be at least one selected from carbon black, carbon nanotubes, and graphene, or at least one selected from carbon nanotubes and graphene.

[0039] The average fiber length of the carbon nanotubes may be 100 μm or less, or 50 μm or less, from the viewpoint of maintaining dispersibility, and the lower limit of the average fiber length may be 0.005 μm, 0.010 μm, or 0.10 μm, from the viewpoint of electromagnetic wave absorption performance. From the viewpoint of insulating properties, the average fiber diameter of the carbon nanotubes may be 1 nm or more and 30 nm or less, or 5 nm or more and 25 nm or less. From the viewpoint of electromagnetic wave absorption ability, the aspect ratio (ratio of fiber length to fiber diameter) of the carbon nanotubes may be 500 or more and 10,000 or less, or 1,000 or more and 5,000 or less. The average fiber length and average fiber diameter of carbon nanotubes can be determined by randomly selecting 100 carbon nanotube samples using a scanning electron microscope (SEM), measuring the fiber length and fiber diameter of each sample, and calculating the number average. The aspect ratio of carbon nanotubes can be calculated from the average fiber length and average fiber diameter values ​​calculated above.

[0040] The carbon nanotubes can be produced by chemical vapor deposition (CVD), arc discharge, and the like. The carbon nanotubes may have either a single-wall structure or a multi-wall structure, and from the viewpoint of cost and availability, the multi-wall structure is preferred.

[0041] Examples of the carbon black include furnace black, channel black, thermal black, acetylene black, and ketjen black. The average particle size of the carbon black is not particularly limited, but may be 1 nm or more and 80 nm or less, or 5 nm or more and 60 nm or less. The average particle size of carbon black can be determined by randomly selecting 100 particles, measuring the particle diameters using a transmission electron microscope (TEM), and calculating the average value.

[0042] The graphene may be any graphene that can be highly dispersed in a matrix resin, and may be graphene oxide containing an organic group. The specific surface area of ​​the graphene is 10 m 2 / g or more 3000m 2 / g or less, and 2 / g or more 1500m 2 / g or less, and 2 / g or more 500m 2 / g or less. The specific surface area is a value measured by the BET one-point method using nitrogen adsorption. In this specification, "graphene" means "a sheet-like material of 10 or fewer layers of sp2-bonded carbon atoms."

[0043] The graphene generally exhibits dispersibility in water and specific polar solvents. The graphene may be highly dispersed in a solvent, and a dispersing aid, which will be described later, may be used in combination. Examples of the solvent include water and organic solvents such as acetone, methyl isobutyl ketone, isopropyl alcohol, and tetrahydrofuran. The concentration of graphene in the dispersion is not particularly limited, but may be 0.01% by mass or more and 10% by mass or less, or 0.1% by mass or more and 5% by mass or less.

[0044] The average particle size of fullerene, graphite, and their derivatives is not particularly limited, but may be 1 nm or more and 10,000 nm or less, or 10 nm or more and 1,000 nm or less. The average particle size can be determined by randomly selecting 100 particles, measuring the particle diameters using a transmission electron microscope (TEM), and calculating the average value.

[0045] When the carbon material of the component (C) contains carbon nanotubes, the content thereof may be 3.0 mass% or less, or may be 1.0 mass% or less, based on the total amount of the resin composition. When the carbon nanotube content is 3.0 mass% or less, the electrical insulating properties of the resin composition can be maintained.

[0046] The content of the carbon material of the component (C) may be from 0.1% by mass to 20% by mass, from 0.2% by mass to 15% by mass, or from 0.3% by mass to 10% by mass, based on the total amount of the resin composition of the present disclosure. When the content of the carbon material of the component (C) is 0.1% by mass or more, the electromagnetic wave absorption performance in the high frequency band of the obtained molded article can be improved, and when it is 20% by mass or less, electrical insulation can be maintained.

[0047] [(D) Dispersing Aid] The resin composition of the present disclosure may further contain a dispersing aid (D). The dispersing aid (D) may be any material capable of stably dispersing fine particles in a matrix resin. Generally, surfactants having functional groups with different reactivity in one molecule and coupling agents are used. Examples of the dispersing aid (D) include anionic surfactants such as carboxylate salts, cationic surfactants such as quaternary ammonium salts, coupling agents having an amine functional group and a sulfide functional group, and cellulose nanofibers. The dispersing aid (D) may be a coupling agent having an amine functional group and a sulfide functional group, or cellulose nanofibers.

[0048] The cellulose nanofibers are bipolar, ultrafine solids that act as surfactants to improve the dispersibility of fillers. The cellulose nanofibers may be already highly dispersed in liquids such as water and thermosetting resin oligomers. The average fiber length of the cellulose nanofibers may be 1 μm or more and 100 μm or less, or 5 μm or more and 50 μm or less, from the viewpoint of workability and fluidity. The average fiber diameter of the cellulose nanofibers, including aggregates, may be 1 nm or more and 1000 nm or less, or 4 nm or more and 500 nm or less. When the average fiber diameter is within the above range, the dispersibility of the (C) component can be improved and the dielectric constant can be reduced. The average fiber length and average fiber diameter of cellulose nanofibers can be measured using a scanning electron microscope (SEM) in the same manner as for the average fiber length and average fiber diameter of carbon nanotubes described above.

[0049] An example of a commercially available coupling agent having an amine functional group and a sulfide functional group is SUMILINK (registered trademark) 100 (manufactured by Sumitomo Chemical Co., Ltd.). An example of a commercially available cellulose nanofiber is ELLEX-S (manufactured by Daio Paper Corporation).

[0050] When the resin composition of the present disclosure contains the dispersing aid of component (D), the content thereof may be 0.1 mass % or more and 30 mass % or less, 0.2 mass % or more and 10 mass % or less, or 0.3 mass % or more and 5 mass % or less, relative to the total amount of the resin composition, from the viewpoints of dispersibility and maintaining thermomechanical properties.

[0051] [(E) Magnetic material] The resin composition of the present disclosure may or may not contain (E) a magnetic material. The magnetic material of component (E) is not particularly limited as long as it is made of a magnetic material generally used for reducing electromagnetic waves. Examples of magnetic materials include soft magnetic materials such as amorphous magnetic metal alloys, Ni-Fe alloys, pure iron, mild steel, silicon steel (Fe-Si alloys), Fe-Al alloys, Fe-Si-Al alloys, Co-Fe alloys, and carbonyl iron, as well as ferrite. These may be used alone or in combination of two or more.

[0052] Specific examples of amorphous magnetic metal alloys include Fe-B-Si, Fe-B-Si-C, Fe-B-Si-Cr, Fe-Co-B-Si, Fe-Ni-Mo-B, Co-Fe-Ni-Mo-B-Si, Co-Fe-Ni-B-Si, etc. Examples of Ni-Fe alloys include 36-permalloy, 45-permalloy, μ-metal, 78-permalloy, Cr-permalloy, Mo-permalloy, and supermalloy.

[0053] Specific examples of ferrite include Mn-Zn ferrite, Ni-Zn ferrite, Cu-Zn ferrite, Cu-Zn-Mg ferrite, Mn-Mg-Al ferrite, Y-type hexagonal ferrite, Z-type hexagonal ferrite, and M-type hexagonal ferrite.

[0054] The magnetic material constituting the magnetic body of component (E) may be silicon steel, Fe-Si-Al alloys, Ni-Fe alloys, or silicon steel from the viewpoint of noise absorption frequency.

[0055] When the resin composition of the present disclosure is used as a semiconductor encapsulant, metal foreign matter removal is performed during the process of manufacturing the semiconductor encapsulant. If the metal foreign matter removal is performed using a magnet, the magnetic material of component (E) is considered to be foreign matter and is removed, resulting in a poor yield. From this perspective, when the resin composition of the present disclosure contains the magnetic material of component (E), its content may be 1% by mass or less, 0.5% by mass or less, or even 0% by mass, relative to the total amount of the resin composition. Furthermore, since the magnetic material of component (E) has a large specific gravity, the content of the magnetic material of component (E) may be the above-mentioned value or less, also from the perspective of reducing the weight of the resulting molded article.

[0056] In addition to the above components, the resin composition of the present disclosure may contain additives, as needed, that are commonly blended into compositions of this type, such as release agents such as synthetic waxes, natural waxes, higher fatty acids, and esters of higher fatty acids; colorants such as cobalt blue; modifiers such as silicone oils and silicone rubbers; hydrotalcites; ion scavengers; and charge control agents, within the scope of the present disclosure. Each of these additives may be used alone or in combination of two or more.

[0057] The content of each of these additives in the resin composition of the present disclosure can be 0.05 mass% or more and 5.0 mass% or less for each additive and the total amount of the additives relative to the total amount of the resin composition, and may be 0.2 mass% or more and 3.0 mass% or less.

[0058] In the resin composition of the present disclosure, the total content of the components (A), (B), and (C) may be 70% by mass or more, or may be 80% by mass or more.

[0059] The resin composition of the present disclosure can be obtained by thoroughly and uniformly mixing the components (A) to (C), the dispersing agent (D), the curing agent, the curing accelerator, and various additives (which are optionally blended) using a mixer or the like, and then kneading the mixture using a disperser, kneader, three-roll mill, twin-screw heated roll, twin-screw heated extrusion kneader, or the like. The kneading may be performed under heating. The temperature may be 70°C or higher and 150°C or lower, or 75°C or higher and 120°C or lower.

[0060] The resin composition of the present disclosure may be used, for example, after the kneading treatment, by cooling and solidifying, and then pulverized to an appropriate size using a cutting mill, ball mill, cyclone mill, hammer mill, vibration mill, cutter mill, grinder mill, speed mill, or the like.

[0061] The mixture obtained after the kneading treatment may be pressed in a molding machine at a temperature of 50° C. to 100° C. and a pressure of 0.5 MPa to 1.5 MPa to form a sheet.

[0062] The resin composition of the present disclosure can be used as an electromagnetic wave absorbing material, an electromagnetic wave absorbing sheet, a semiconductor encapsulant, an encapsulating sheet, a wire covering material, and the like. In one embodiment of the present disclosure, the electromagnetic wave absorbing material can be used as a semiconductor encapsulant. For example, a semiconductor element fixed on a substrate can be encapsulated with the resin composition of the present disclosure to obtain a resin-encapsulated electronic component. To obtain electronic components, any known molding method can be used without any particular limitation. The most common molding method is low-pressure transfer molding, but molding by injection molding, cast molding, compression molding, etc. is also possible.

[0063] For example, in the case of transfer molding, a heat treatment may be carried out in a mold using a transfer molding machine at a temperature of 150°C or higher and 200°C or lower for a time of 20 seconds or higher and 200 seconds or lower, and the molded product may then be removed from the mold and subjected to a heat treatment to complete curing at a temperature of 150°C or higher and 200°C or lower for 2 hours or higher and 12 hours or lower.

[0064] In the case of compression molding, a substrate mounted with a semiconductor element is first supplied to the upper mold of a molding die, and the resin composition of the present disclosure is supplied to the cavity of the lower mold. Next, the upper and lower molds are clamped together at a required clamping pressure, and the substrate mounted with the semiconductor element is immersed in the heated and melted resin composition in the lower mold cavity. Thereafter, the heated and melted resin composition in the lower mold cavity is pressed with a cavity bottom member, and a required pressure is applied under reduced pressure to perform compression molding. Molding conditions may be a temperature of 120°C to 200°C and a pressure of 2 MPa to 20 MPa.

[0065] 1 shows an example of an electronic component 10 according to the present disclosure obtained in this manner, in which an adhesive layer 3 may be interposed between a lead frame 1, such as a copper frame, and a semiconductor element 2. Electrodes 4 on the semiconductor element 2 and leads 5 of the lead frame 1 are connected by bonding wires 6, and these are further subjected to electromagnetic wave absorption by a molded product (encapsulant) 7 of the resin composition according to the present disclosure.

[0066] The type of semiconductor element to be encapsulated with the resin composition of the present disclosure is not particularly limited, and may be a semiconductor element for a smart device. In addition, when compression molding is used, the thickness of the electronic component after molding may be 0.2 mm or more and 1.5 mm or less.

[0067] In this way, by using the resin composition of the present disclosure to absorb electromagnetic waves from semiconductor elements, electronic components with excellent electromagnetic wave absorption performance in the high frequency band can be obtained.

[0068] The electromagnetic wave absorption performance of an article molded from the resin composition of the present disclosure may be −3 dB or less, −5 dB or less, or −10 dB or less. The electromagnetic wave absorption performance is measured by placing a compression-molded molded body having a thickness of 0.5 mm between a high-frequency oscillation device and a receiving antenna, generating electromagnetic waves with a measurement frequency of 10 GHz, measuring the electromagnetic wave intensity with and without the molded body, and expressing the ratio (electromagnetic wave intensity when electromagnetic waves are absorbed by the molded body / electromagnetic wave intensity when the molded body is not present) in dB units. The electromagnetic wave intensity can be measured in accordance with the Transactions of the Institute of Electronics, Information and Communication Engineers, Vol. J97-B, No. 3, pp. 279-285. [Example]

[0069] The present disclosure will now be described in detail with reference to examples, but the present disclosure is not limited to these examples in any way.

[0070] (Examples 1 to 22 and Comparative Examples 1 to 6) The components of the types and amounts shown in Tables 1-1, 1-2, and 2 were charged into a Henschel mixer, mixed, and then charged into a twin-screw roll kneader heated to 110°C, where they were heated and kneaded until homogenous. Next, the heated and kneaded mixture was charged into a cold roll, stretched into a sheet, and pulverized to obtain a resin composition that is a molding material for an electromagnetic wave absorber.

[0071] Details of each component used in preparing the resin composition and shown in Tables 1-1, 1-2 and 2 are as follows.

[0072] [(A) Resin] Epoxy resin 1: Epomic (registered trademark) R140; liquid bisphenol A type epoxy resin; manufactured by Mitsui Chemicals, Inc., epoxy equivalent: 189, ε′′ (25°C, 10 GHz) = 0.04, ε′ (25°C, 10 GHz) = 2.5 Epoxy resin 2: Rikaresin BEO-60E; a liquid epoxy resin having a bisphenol A skeleton (mainly composed of bisphenol A bis(triethylene glycol glycidyl ether) ether) (compound represented by the general formula (1)); manufactured by New Japan Chemical Co., Ltd., epoxy equivalent: 365, ε′′ (25°C, 10 GHz) = 0.20, ε′ (25°C, 10 GHz) = 3.0 Epoxy resin 3: Epolite 400E; polyethylene glycol diglycidyl ether (mainly composed of the compound represented by the general formula (2)); manufactured by Kyoeisha Chemical Co., Ltd., epoxy equivalent: 277, ε′′ (25°C, 10 GHz) = 0.20, ε′ (25°C, 10 GHz) = 3.0 Imide resin 1: BANI-M; bisallylnadiimide; manufactured by Maruzen Petrochemical Co., Ltd., ε′′ (25°C, 10 GHz) = 0.07, ε′ (25°C, 10 GHz) = 2.5

[0073] [(B) Inorganic filler] Silica: FB105FC; manufactured by Denka Co., Ltd., average particle size: 20 μm, maximum particle size: 50 μm, ε′′ (25°C, 10 GHz) = 0.001 Silicon carbide (SiC): Diasic; manufactured by Yakushima Electric Co., Ltd., average particle size: 5 μm, maximum particle size: 10 μm, ε′′ (25°C, 10 GHz) = 2.0 Alumina: DAW07; manufactured by Denka Co., Ltd., average particle size: 8 μm, maximum particle size: 50 μm, ε′′ (25°C, 10 GHz) = 0.1

[0074] The ε'' and ε' of the (A) resin and the ε'' of the (B) inorganic filler were measured by the following method. The (A) resin was added to each resin in an amount equivalent to 1 of the curing agent, and the mixture was placed in a mold and compression molded (temperature: 175°C, pressure: 10 MPa) into plates with a thickness of 1.0 mm. The (B) inorganic filler was placed in a mold and fired (temperature: 1500°C, 10 hours) to form a plate with a thickness of 1.0 mm after sintering. Using the obtained plate, measurements were performed at a temperature of 25°C using a network analyzer (Agilent PNA E8363B) and a rectangular waveguide (WRJ-10) in the frequency range of 8.20 GHz to 12.40 GHz, and the respective values ​​at 10 GHz were obtained.

[0075] [(C) Carbon material] Carbon nanotubes (CNT): LUCAN; LG, average fiber length: 30 μm, average fiber diameter: 0.02 μm, aspect ratio: 1500 Carbon black (CB): CB30; manufactured by Mitsubishi Chemical Corporation, average particle size: 50 nm Graphene: Graphene Nanoplatelet H: XG-Science, specific surface area (BET method): 30m 2 / g

[0076] [(D) Dispersing Aid] Cellulose nanofiber: ELLEX-S; manufactured by Daio Paper Co., Ltd., average fiber diameter: 20-200 nm Coupling agent: SUMILINK (registered trademark) 100; S-(3-aminopropyl thiosulfate); manufactured by Sumitomo Chemical Co., Ltd.

[0077] [(E) Magnetic material] ·Fe-Si-Cr powder: manufactured by Nippon Atomize Kako Co., Ltd., specific gravity: 7.6, average particle size: 11μm

[0078] [Curing agent] Hardener 1: MEH7500; triphenylmethane type phenolic resin; manufactured by Meiwa Kasei Co., Ltd.

[0079] [Curing accelerator] Curing accelerator 1: Curazol C11Z; imidazole compound; manufactured by Shikoku Chemical Industry Co., Ltd. Curing accelerator 2: Percumyl D; organic peroxide; NOF Corporation

[0080] (evaluation) For each of the resin compositions obtained in Examples 1 to 22 and Comparative Examples 1 to 6, a molded article having a thickness of 0.5 mm or 1.0 mm was compression molded (temperature: 175°C, pressure: 10 MPa). The complex dielectric constant, volume resistivity, thermal conductivity, and electromagnetic wave absorption performance were measured by the following methods. The evaluation results are shown in Tables 1-1, 1-2, and 2.

[0081] (1) Complex permittivity (real part: ε′, imaginary part: ε′′) and dielectric tangent (tanδ) The dielectric properties were measured using a 1.0 mm thick molded body at a temperature of 25°C using a network analyzer (Agilent PNA E8363B) and a rectangular waveguide (WRJ-10) in the frequency range of 8.20 GHz to 12.40 GHz, and the respective values ​​at 10 GHz were obtained.

[0082] (2) Volume resistivity (ρv) Using a molded body having a thickness of 1.0 mm, the volume resistivity at 150°C was measured in accordance with JIS K-6911:2006.

[0083] (3)(log ρv)×ε′′ The product of ε'' and the logarithm of ρv was calculated from ε'' measured in (1) above and ρv measured in (2) above.

[0084] (4) Thermal conductivity Laser light was irradiated onto one side of a 1.0 mm thick molded body, providing heat flow energy with periodically modulated intensity. A temperature sensor was used to detect the phase difference in the temperature response on the other side of the molded body, and the thermal diffusivity and specific heat were determined, from which the thermal conductivity was calculated.

[0085] (5) Specific gravity A disk-shaped compact having a thickness of 2.0 mm and a diameter of 5 mm was obtained by compression molding (temperature: 180°C, pressure: 5 MPa). The specific gravity of the compact was determined by measuring the mass and buoyancy of the compact in air and in water using a balance, based on the liquid weighing method of JIS Z 8807:2012, a method for measuring the density and specific gravity of solids.

[0086] (6) Thermal expansion coefficient (α1) Using the TMA method, a thermal analyzer (Seiko Instruments Inc., product name: SSC / 5200) was used to raise the temperature from room temperature (25°C) to 300°C at a heating rate of 5°C / min, and the slope of the part of the resulting TMA chart that was closest to a straight line between 25 and 60°C was taken as the linear expansion coefficient α1.

[0087] (7) Electromagnetic wave absorption performance A 0.5 mm thick molded body was placed between a high-frequency oscillator device and a receiving antenna, and the electromagnetic wave intensity when an electromagnetic wave with a frequency of 10 GHz was generated was measured with and without the molded body, and the ratio (electromagnetic wave intensity when electromagnetic wave is absorbed by the molded body / electromagnetic wave intensity when the molded body is not present) was taken as the electromagnetic wave absorption capacity in dB. The electromagnetic wave intensity was measured in accordance with the Transactions of the Institute of Electronics, Information and Communication Engineers, Vol. J97-B, No. 3, pp. 279-285.

[0088] [Table 1-1]

[0089] [Table 1-2]

[0090] [Table 2]

[0091] It is clear that a molded article made from a resin composition that satisfies the formula (1) and has the imaginary part (ε'') of greater than 1.25 has excellent electromagnetic wave absorption performance in the high frequency band. [Explanation of symbols]

[0092] 10. Electronic Components 1 lead frame 2. Semiconductor elements 3 Adhesive layer 4 electrodes 5 Lead section 6 Bonding Wire 7. Molded body of resin composition (sealing material)

Claims

1. a molded article of the resin composition is an electromagnetic wave absorber, The molded product has an imaginary part (ε") of a complex dielectric constant at 25°C and 10 GHz and a volume resistivity (ρv) at 25°C that satisfy the following formula (1), and the imaginary part (ε") is greater than 1.25: 20<(log ρv)×ε′′<600 (1) The resin composition is a resin composition containing (A) at least one resin selected from a thermosetting resin and a thermoplastic resin, (B) an inorganic filler (excluding component (C)), and (C) a carbon material, and satisfies at least any of the following (i), (ii), and (iii): (i) The component (A) is an epoxy resin having a polyoxyalkylene structure. (ii) The component (B) is silicon carbide. (iii) The component (C) is at least one selected from carbon nanotubes and graphene.

2. a molded article of the resin composition is an electromagnetic wave absorber, The molded product has an imaginary part (ε") of a complex dielectric constant at 25°C and 10 GHz and a volume resistivity (ρv) at 25°C that satisfy the following formula (1), and the imaginary part (ε") is greater than 1.25: 20<(log ρv)×ε′′<600 (1) The resin composition contains (A) at least one resin selected from a thermosetting resin and a thermoplastic resin, (B) an inorganic filler (excluding component (C)), and (C) a carbon material, and satisfies the following (i) and further satisfies (ii) or (iii): (i) The component (A) is an epoxy resin having a polyoxyalkylene structure. (ii) The component (B) is silicon carbide. (iii) The component (C) is at least one selected from carbon nanotubes and graphene.

3. a molded article of the resin composition is an electromagnetic wave absorber, The molded product has an imaginary part (ε") of a complex dielectric constant at 25°C and 10 GHz and a volume resistivity (ρv) at 25°C that satisfy the following formula (1), and the imaginary part (ε") is greater than 1.25: 20<(log ρv)×ε′′<600 (1) The resin composition contains (A) at least one resin selected from a thermosetting resin and a thermoplastic resin, (B) an inorganic filler (excluding component (C)), and (C) a carbon material, and satisfies the following (i), (ii), and (iii): (i) The component (A) is an epoxy resin having a polyoxyalkylene structure. (ii) The component (B) is silicon carbide. (iii) The component (C) is at least one selected from carbon nanotubes and graphene.

4. 4. The resin composition according to claim 1, wherein the molded article has a real part (ε') of complex dielectric constant of less than 40 at 25° C. and 10 GHz.

5. 5. The resin composition according to claim 1, wherein the thermal expansion coefficient of the molded article is 1 to 40 ppm / deg.

6. An electronic part comprising a molded article of the resin composition according to any one of claims 1 to 5.

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