WO2018168786A1 - 電磁波シールド部材 - Google Patents
電磁波シールド部材 Download PDFInfo
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- WO2018168786A1 WO2018168786A1 PCT/JP2018/009549 JP2018009549W WO2018168786A1 WO 2018168786 A1 WO2018168786 A1 WO 2018168786A1 JP 2018009549 W JP2018009549 W JP 2018009549W WO 2018168786 A1 WO2018168786 A1 WO 2018168786A1
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0084—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0086—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single discontinuous metallic layer on an electrically insulating supporting structure, e.g. metal grid, perforated metal foil, film, aggregated flakes, sintering
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0088—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a plurality of shielding layers; combining different shielding material structure
Definitions
- the present invention relates to an electromagnetic wave shielding member.
- Patent Document 1 discloses an electromagnetic wave in which a wallpaper backing paper layer made of a thin paper and an intermediate peelable paper is provided at least on the back side of an aluminum foil via an adhesive layer, and an insertion hole is formed by needle projections. Shield wallpaper is described ([Claim 1]). Patent Document 1 describes that the electromagnetic wave shielding characteristic of 50 dB or more is provided in the frequency band of 1 GHz to 8 GHz ([Table 1]).
- electromagnetic waves in a communication frequency band are shielded to suppress that an electric field wave from the outside enters the electronic device and becomes a noise source.
- an electromagnetic wave shielding member that transmits electromagnetic waves.
- Patent Document 2 is a laminate in which a layer (A) made of a metal and a dielectric is provided on one side of a transparent thermoplastic resin film, and a metal layer (B) is provided on the other side thereof.
- the coverage of the metal portion to the film area in the layer (B) plane is 20% to 80%, and the ratio of the visible light transmittance (Tvis) to the near infrared transmittance (Tnir) of the laminate (Tnir / Tvis)
- An electromagnetic wave shielding laminate having an electric wave shield characteristic of 30 dB or more in a frequency band of 80 MHz to 1000 MHz is described (claim 1).
- high shield characteristics can be obtained by using a metallic shield member having a large through hole such as a wire mesh. Therefore, the transparency in the visible light region can be increased.
- high shield characteristics can not be obtained with a shield member having a large through hole such as a metal mesh, so high shield characteristics and ultraviolet region, visible light region, near infrared region, and There is a problem that it is not possible to simultaneously achieve the transmission of electromagnetic waves in the mid-infrared region.
- this invention makes it a subject to provide the electromagnetic wave shielding member which has a high shielding characteristic with respect to the electromagnetic waves of GHz band, and can permeate
- the inventor of the present invention has a metal foil in which a plurality of through holes penetrating in the thickness direction are formed, the average opening diameter of the through holes is 1 ⁇ m to 100 ⁇ m, and the average opening ratio is 1%.
- the transmittance of electromagnetic waves from the ultraviolet region to the visible region is half the wavelength of the average aperture diameter of the through holes.
- the transmittance of electromagnetic waves from the ultraviolet region to the visible region is the absolute value -5% of the average aperture ratio of the through holes
- the transmittance of electromagnetic waves up to a wavelength half the length of the average opening diameter of the through holes is at least 10% of the average opening ratio
- the average opening of the through holes is UV range to near red at aperture of 5 ⁇ m or more
- the electromagnetic wave transmittance of the region is an absolute value of the average aperture ratio of the through holes in the range of -5% to + 5%, and in the mid-infrared region, electromagnetic waves up to a wavelength half the average aperture diameter of the through holes.
- a metal foil provided with a plurality of through holes penetrating in the thickness direction,
- the average opening diameter of the through holes is 1 ⁇ m to 100 ⁇ m, and the average opening ratio is 1% to 50%,
- the transmittance of the electromagnetic wave from the ultraviolet region to the visible region is 10% or more of the average aperture ratio, until the wavelength of half the length of the average aperture diameter of the through hole.
- the absolute value of the average aperture ratio of through holes is in the range of -5% to + 5% from the ultraviolet region to the visible region
- the transmittance of electromagnetic waves up to a wavelength half the length of the average opening diameter of the through holes is 10% or more of the average opening ratio
- the transmittance of electromagnetic waves from the ultraviolet region to the near infrared region is in the range of the absolute value of the average aperture ratio of through holes in the range of -5% to + 5%
- An electromagnetic wave shield member wherein in the mid-infrared region, the transmittance of electromagnetic waves up to a wavelength half the length of the average aperture diameter of the through holes is 10% or more of the average aperture ratio.
- the metal foil is aluminum foil, copper foil, silver foil, gold foil, platinum foil, stainless steel foil, titanium foil, tantalum foil, molybdenum foil, niobium foil, zirconium foil, tungsten foil, beryllium copper foil, phosphor blue copper foil, brass Foil, nickel foil, tin foil, lead foil, zinc foil, solder foil, iron foil, nickel foil, permalloy foil, nichrome foil, 42 alloy foil, kovar foil, monel foil, inconel foil, and hastelloy foil.
- an electromagnetic wave shielding member having high shielding characteristics against electromagnetic waves in the GHz band and capable of transmitting electromagnetic waves in the ultraviolet region to the mid-infrared region.
- a numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value.
- the electromagnetic wave shielding member of the present invention is A metal foil in which a plurality of through holes penetrating in the thickness direction are formed,
- the average opening diameter of the through holes is 1 ⁇ m to 100 ⁇ m, and the average opening ratio is 1% to 50%,
- the transmittance of electromagnetic waves up to a wavelength half the length of the average aperture diameter of the through holes in the ultraviolet region to the visible region is 10% or more of the average aperture ratio,
- the transmittance of electromagnetic waves from the ultraviolet region to the visible region is in the range of -5% to + 5% of the absolute value of the average aperture ratio of the through holes,
- the transmittance of electromagnetic waves up to a wavelength half the length of the average opening diameter of the through holes is 10% or more of the average opening ratio
- FIG. 1 is a schematic plan view showing an example of a preferred embodiment of the electromagnetic wave shielding member of the present invention.
- FIG. 2 is a cross-sectional view taken along the line BB of FIG.
- the electromagnetic wave shield member 10 shown in FIGS. 1 and 2 has a plurality of through holes 5 penetrating the metal foil 3 in the thickness direction.
- the average opening diameter of the through holes formed in the metal foil is 1 ⁇ m to 100 ⁇ m, the average opening ratio is 1% to 50%, and the average opening diameter of the through holes is 1 ⁇ m or more
- the transmittance of the electromagnetic wave from the ultraviolet region to the visible region is 10% or more of the average aperture ratio to the wavelength of half the length of the average aperture diameter of the through holes.
- the transmittance of electromagnetic waves from the ultraviolet region to the visible region is in the range of absolute value -5% to + 5% of the average aperture ratio of through holes.
- the transmittance of electromagnetic waves up to a wavelength half the length of the average opening diameter of the through holes is 10% or more of the average opening ratio, and the average opening diameter of the through holes is 5 ⁇ m or more
- Transmissivity of electromagnetic waves from the ultraviolet region to the near infrared region The absolute value of the average aperture ratio is in the range of -5% to + 5%, and in the mid-infrared region, the electromagnetic wave transmittance up to a wavelength half the average aperture diameter of the through holes is 10% of the average aperture ratio It is above.
- a through hole having an average opening diameter and an average opening ratio in the above range is formed in a metal foil, and an ultraviolet region or visible light region according to the average opening diameter of the through hole.
- the transmittances in the near infrared region and the mid infrared region are in the above range.
- the average opening diameter of the through hole is obtained by photographing the surface of the electromagnetic wave shielding member at a magnification of 100 to 10000 using a high resolution scanning electron microscope (SEM) from one surface of the electromagnetic wave shielding member.
- SEM scanning electron microscope
- the magnification of the range mentioned above can be suitably selected so that the SEM photograph which can extract 20 or more through holes can be obtained.
- the opening diameter measured the maximum value of the distance between the ends of the through-hole part.
- the shape of the opening of the through hole is not limited to a substantially circular shape, when the shape of the opening is non-circular, the maximum value of the distance between the end portions of the through holes is taken as the opening diameter. Therefore, for example, even in the case of a through hole having a shape in which two or more through holes are integrated, this is regarded as one through hole, and the maximum value of the distance between the ends of the through hole portions is taken as the opening diameter. .
- the average aperture ratio of the through holes is determined by installing a parallel light optical unit on one side of the electromagnetic wave shielding member and transmitting the parallel light, and using the optical microscope from the other side of the electromagnetic wave shielding member. The surface of the member is photographed at a magnification of 100 times to obtain a photograph. From the sum of the aperture area of the through holes projected by the parallel light transmitted and the area (geometrical area) of the visual field, for the 100 mm ⁇ 75 mm visual field (5 places) in the range of 10 cm ⁇ 10 cm of the obtained photograph The ratio (aperture area / geometrical area) is calculated, and the average value in each visual field (five places) is calculated as an average aperture ratio.
- the ultraviolet region to the visible light region is a band having a wavelength of 250 nm or more and less than 750 nm including the ultraviolet region and the visible light region.
- the near infrared region is a band having a wavelength of 750 nm or more and less than 2500 nm. Therefore, the ultraviolet region to the near infrared region is a band having a wavelength of 250 nm or more and less than 2500 nm including the ultraviolet region, the visible light region, and the near infrared region.
- region is a zone
- the electromagnetic wave transmittance is such that an electromagnetic wave of a specific frequency is transmitted in the shield box, the other side receives the electromagnetic wave passing through the electromagnetic wave shielding member, and passes the electromagnetic wave shielding member against the intensity of the electromagnetic wave before passing through the electromagnetic wave shielding member It can be determined as the ratio of the intensity of the electromagnetic wave after the
- the transmittance of the electromagnetic wave in each of the wavelength ranges described above is an average value of the transmittance of the electromagnetic waves in the corresponding wavelength range.
- the electromagnetic waves in the GHz band are electromagnetic waves in the frequency band of 1 GHz to 18 GHz.
- the average value of the electromagnetic wave shield characteristics in the frequency band of 1 GHz to 18 GHz can be set to 60 dB or more.
- the electromagnetic wave shield characteristics represent the ratio of the electric field strength before passing through the electromagnetic wave shield member to the electric field strength after passing through the electromagnetic wave shield member in logarithm.
- the average opening diameter of the through holes is preferably 1 ⁇ m or more and 45 ⁇ m or less, more preferably 1 ⁇ m or more and 40 ⁇ m or less, and still more preferably 1 ⁇ m or more and 30 ⁇ m or less.
- the electromagnetic wave shield characteristics can be made more preferable. Further, even when the electromagnetic wave shielding member has a large number of through holes, it can have sufficient tensile strength.
- the average opening ratio of the through holes is preferably 2% to 45%, more preferably 2% to 30%, and still more preferably 2% to 20%.
- the electromagnetic wave shield characteristics can be made more preferable. Further, even when the electromagnetic wave shielding member has a large number of through holes, it can have sufficient tensile strength.
- the metal foil is not limited as long as it is a foil having high shielding properties against electromagnetic waves in the GHz band, but it is composed of a metal and / or a metal compound which can easily form the through holes of the above-mentioned average aperture diameter and average aperture ratio. Is preferred, and foils composed of metals are more preferred. Moreover, it is also preferable that it is metal foil containing the metal atom melt
- the metal foil include aluminum foil, copper foil, silver foil, gold foil, platinum foil, stainless steel foil, titanium foil, tantalum foil, tantalum foil, molybdenum foil, niobium foil, zirconium foil, tungsten foil, beryllium copper foil, Phosphorus blue copper foil, yellow copper foil, nickel foil, tin foil, lead foil, zinc foil, solder foil, iron foil, nickel foil, permalloy foil, nichrome foil, 42 alloy foil, kovar foil, monel foil, inconel foil, and hastelloy Foil etc. are mentioned.
- the metal foil may be a laminate of two or more different metals including the above-mentioned types of metals.
- the method of laminating the metal foil is not particularly limited, but is preferably a plated or clad material.
- the metal used for plating is preferably a metal containing a metal atom that dissolves in the etchant, and is preferably a metal.
- plating species include nickel, chromium, cobalt, iron, zinc, tin, copper, silver, gold, platinum, palladium, and aluminum.
- the method of plating is not particularly limited, and any of electroless plating, electrolytic plating, hot-dip plating, and chemical conversion treatment may be used.
- the metal used to form the clad material for the metal foil is preferably a metal containing a metal atom that dissolves in an etchant, and is preferably a metal.
- As a metal seed the metal used for the said metal foil is mentioned, for example.
- the average thickness of the metal foil is preferably 5 ⁇ m to 1000 ⁇ m. From the viewpoint of handleability, the average thickness of the metal foil is more preferably 5 ⁇ m to 50 ⁇ m, and still more preferably 8 ⁇ m to 30 ⁇ m.
- the average thickness of metal foil refers to the average value of the thickness which measured arbitrary five points using the contact-type film thickness measurement meter (digital electronic micrometer).
- the aluminum in the case of using aluminum as the metal foil is not particularly limited, and for example, known aluminum alloys such as 3000 series (for example, 3003 material etc.) and 8000 series (for example, 8021 material etc.) can be used. .
- known aluminum alloys such as 3000 series (for example, 3003 material etc.) and 8000 series (for example, 8021 material etc.) can be used.
- an aluminum alloy for example, an aluminum alloy having an alloy number shown in Table 1 below can be used.
- the manufacturing method of the electromagnetic wave shielding member of this invention is demonstrated.
- the manufacturing method of an electromagnetic wave shield member is not specifically limited, When using an aluminum base as metal foil, the film formation process of forming an aluminum hydroxide film in at least one surface of an aluminum base, for example, film formation After the process, a through hole forming process 1 is performed to form a through hole, a through hole forming process 1 is performed, a through hole forming process 1 is followed by a film removing process of removing an aluminum hydroxide film, and a through film removing process And a resin layer forming step of forming a resin layer on at least one surface of the aluminum base having holes.
- FIGS. 3 to 6 are schematic cross-sectional views showing an example of a preferred embodiment of the method of manufacturing an electromagnetic wave shielding member.
- the film forming process is performed on both surfaces of the aluminum base 1 to form an aluminum hydroxide film 2 (FIGS. 3 and 4)
- the electrolytic solution treatment is performed after the film forming step to form the through hole 5, and the through hole forming step 1 of producing a laminate having the aluminum base 3 having the through hole and the aluminum hydroxide film 4 having the through hole.
- the through hole forming step 1 (FIG. 4 and FIG. 5)
- the aluminum hydroxide film 4 having the through hole is removed, and the film removing step of producing the aluminum base 3 having the through hole (FIG. 5 and FIG. 6) And B.).
- the present invention is not limited to this, and aluminum hydroxide is formed only on one side of the aluminum base 1. It may form the film 2.
- the film forming step included in the method of manufacturing the electromagnetic wave shielding member is a step of forming a film of aluminum hydroxide by subjecting the surface of the aluminum substrate to a film forming treatment.
- the film formation process is not particularly limited, and, for example, the same process as the conventionally known aluminum hydroxide film formation process can be performed.
- the film formation process for example, the conditions and apparatus described in paragraphs [0013] to [0026] of JP-A-2011-201123 can be appropriately adopted.
- the conditions of the film formation treatment can not be determined indiscriminately because they vary depending on the electrolyte used, but generally, the electrolyte concentration is 1 to 80 mass%, the solution temperature is 5 to 70 ° C. It is appropriate that the current density is 0.5 to 60 A / dm 2 , the voltage is 1 to 100 V, and the electrolysis time is 1 second to 20 minutes, and it is adjusted to obtain a desired amount of film.
- electrochemical treatment using nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid or oxalic acid, or a mixed acid of two or more of these acids as an electrolytic solution.
- direct current may be applied between the aluminum base and the counter electrode, and alternating current may be applied.
- the current density is preferably 1 to 60 A / dm 2 , more preferably 5 to 50 A / dm 2 .
- the amount of the aluminum hydroxide film formed by the film forming treatment is preferably 0.05 to 50 g / m 2 , and more preferably 0.1 to 10 g / m 2 .
- the through hole forming step 1 is a step of performing electrolytic dissolution treatment after the film forming step to form a through hole.
- the electrolytic dissolution treatment is not particularly limited, and an acidic solution can be used as the electrolytic solution using direct current or alternating current.
- electrochemical treatment is preferably performed using at least one of nitric acid and hydrochloric acid, and electrochemical treatment is performed using a mixed acid obtained by adding at least one or more acids of sulfuric acid, phosphoric acid and oxalic acid to these acids. It is more preferable to
- the concentration of the acidic solution is preferably 0.1 to 2.5% by mass, particularly preferably 0.2 to 2.0% by mass.
- the liquid temperature of the acidic solution is preferably 20 to 80 ° C., and more preferably 30 to 60 ° C.
- the aqueous solution mainly composed of the acid is a nitrate compound having aluminum nitrate, sodium nitrate and / or nitrate ion such as ammonium nitrate in the aqueous solution of acid having a concentration of 1 to 100 g / L, or aluminum chloride, sodium chloride and And / or adding at least one of a hydrochloric acid compound having a hydrochloric acid ion such as ammonium chloride, aluminum sulfate, sodium sulfate, and / or a sulfuric acid compound having a sulfate ion such as ammonium sulfate in the range from 1 g / L to saturation It can be used.
- a hydrochloric acid compound having a hydrochloric acid ion such as ammonium chloride, aluminum sulfate, sodium sulfate, and / or a sulfuric acid compound having a sulfate ion such as ammonium sul
- mainly contained means that the component which becomes the main component in the aqueous solution is contained in an amount of 30% by mass or more, preferably 50% by mass or more, with respect to the entire components added to the aqueous solution.
- the metal contained in aluminum alloys such as iron, copper, manganese, nickel, titanium, magnesium, and / or a silica, may be melt
- a solution obtained by adding aluminum chloride, aluminum nitrate, and / or aluminum sulfate or the like to an aqueous solution with an acid concentration of 0.1 to 2% by mass so that aluminum ion is 1 to 100 g / L is used. preferable.
- the alternating current power supply wave is not particularly limited when using alternating current, and sine wave, rectangular wave, trapezoidal wave, and / or triangular wave, etc. Among them, rectangular waves or trapezoidal waves are preferable, and trapezoidal waves are particularly preferable.
- nitric acid electrolysis In the present invention, through holes having an average opening diameter of 1 ⁇ m to 100 ⁇ m can be easily obtained by electrochemical dissolution treatment using an electrolyte mainly composed of nitric acid (hereinafter also referred to as “nitric acid dissolution treatment”). It can be formed.
- nitric acid dissolution treatment the condition that the average current density is 5 A / dm 2 or more and the amount of electricity is 50 C / dm 2 or more using a direct current because it is easy to control the dissolution point of through hole formation It is preferable that it is the electrolytic treatment given by.
- the average current density is preferably 100 A / dm 2 or less, and the amount of electricity is preferably 10000 C / dm 2 or less.
- concentration and temperature of the electrolyte in nitric acid electrolysis are not particularly limited, and electrolysis is performed at 30 to 60 ° C. using a high concentration nitric acid electrolyte having a nitric acid concentration of 15 to 35 mass%, for example. Electrolysis can be performed at a high temperature, for example, 80 ° C. or higher, using a 7 to 2% by mass nitric acid electrolyte. Further, electrolysis can be performed using an electrolytic solution prepared by mixing at least one of sulfuric acid, oxalic acid and phosphoric acid at a concentration of 0.1 to 50% by mass with the above nitric acid electrolytic solution.
- a through-hole having an average opening diameter of 1 ⁇ m to 100 ⁇ m can be easily obtained by electrochemical dissolution treatment using an electrolyte mainly composed of hydrochloric acid (hereinafter also abbreviated as “hydrochloric acid dissolution treatment”).
- hydrochloric acid dissolution treatment the condition that the average current density is 5 A / dm 2 or more and the amount of electricity is 50 C / dm 2 or more using a direct current because it is easy to control the dissolution point of through hole formation It is preferable that it is the electrolytic treatment given by.
- the average current density is preferably 100 A / dm 2 or less, and the amount of electricity is preferably 10000 C / dm 2 or less.
- the concentration and temperature of the electrolytic solution in hydrochloric acid electrolysis are not particularly limited, and electrolysis is carried out at 30 to 60 ° C. using a high concentration, for example, a hydrochloric acid electrolytic solution having a hydrochloric acid concentration of 10 to 35 mass%.
- the electrolysis can be performed at a high temperature, for example, 80 ° C. or more, using a 7 to 2% by mass hydrochloric acid electrolyte solution. Further, electrolysis can be performed using an electrolytic solution obtained by mixing at least one of sulfuric acid, oxalic acid and phosphoric acid at a concentration of 0.1 to 50% by mass with the above-mentioned hydrochloric acid electrolytic solution.
- the film removal step is a step of chemical dissolution treatment to remove the aluminum hydroxide film.
- the aluminum hydroxide film can be removed, for example, by performing an acid etching treatment and / or an alkali etching treatment described later.
- the solution treatment is a treatment in which an aluminum hydroxide film is dissolved using a solution in which aluminum hydroxide is preferentially dissolved in preference to aluminum (hereinafter referred to as “aluminum hydroxide solution”).
- the aluminum hydroxide solution for example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, chromium compound, zirconium compound, titanium compound, lithium salt, cerium salt, magnesium salt, sodium silicofluoride, fluoride fluoride
- An aqueous solution containing at least one selected from the group consisting of zinc, a manganese compound, a molybdenum compound, a magnesium compound, a barium compound and a halogen alone is preferred.
- examples of the chromium compound include chromium (III) oxide and chromium (VI) anhydride.
- zirconium-based compound include ammonium zirconium fluoride, zirconium fluoride, and zirconium chloride.
- titanium compounds include titanium oxide and titanium sulfide.
- lithium salt lithium fluoride and lithium chloride are mentioned, for example.
- cerium salt cerium fluoride and cerium chloride are mentioned, for example.
- magnesium salt magnesium sulfide is mentioned, for example.
- manganese compound sodium permanganate and calcium permanganate are mentioned, for example.
- sodium molybdenum compound sodium molybdate is mentioned, for example.
- magnesium fluoride pentahydrate is mentioned, for example.
- a barium compound for example, barium oxide, barium acetate, barium carbonate, barium chlorate, barium chloride, barium fluoride, barium iodide, barium lactate, barium oxalate, barium perchlorate, barium selenate, selenious acid
- barium stearate, barium sulfite, barium titanate, barium hydroxide, and barium nitrate, and hydrates thereof examples of the above-mentioned barium compounds, barium oxide, barium acetate and barium carbonate are preferable, and barium oxide is particularly preferable.
- Examples of halogen alone include chlorine, fluorine and bromine.
- the aluminum hydroxide solution is an aqueous solution containing an acid
- examples of the acid include nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and oxalic acid, and a mixture of two or more acids. May be Among them, it is preferable to use nitric acid as the acid.
- the acid concentration is preferably 0.01 mol / L or more, more preferably 0.05 mol / L or more, and still more preferably 0.1 mol / L or more.
- the upper limit is not particularly limited, but generally 10 mol / L or less is preferable, and 5 mol / L or less is more preferable.
- the dissolution treatment is carried out by bringing the aluminum base on which the aluminum hydroxide film is formed into contact with the above-mentioned solution.
- the method for contacting is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the immersion method is preferred.
- the immersion method is a process of immersing the aluminum base on which the aluminum hydroxide film is formed in the above-described solution. Stirring during the immersion treatment is preferable because the treatment without unevenness is performed.
- the immersion treatment time is preferably 10 minutes or more, more preferably 1 hour or more, and still more preferably 3 hours or more and 5 hours or more.
- the alkali etching treatment is a treatment in which the surface layer is dissolved by bringing the aluminum hydroxide film into contact with an alkali solution.
- alkali used for the alkali solution examples include caustic alkali and alkali metal salts.
- caustic alkali examples include sodium hydroxide (caustic soda) and caustic potash.
- alkali metal salt for example, alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate and potassium silicate; sodium carbonate and alkali metal carbonates such as potassium carbonate; Alkali metal aluminates such as sodium acid and potassium aluminate; Alkali metal aldonates such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate and tribasic sodium phosphate And alkali metal hydrogen phosphates such as potassium triphosphate.
- a solution of caustic alkali and a solution containing both caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost.
- an aqueous solution of sodium hydroxide is preferred.
- the concentration of the alkaline solution is preferably 0.1 to 50% by mass, and more preferably 0.2 to 10% by mass.
- concentration of aluminum ions is preferably 0.01 to 10% by mass, and more preferably 0.1 to 3% by mass.
- the temperature of the alkaline solution is preferably 10 to 90.degree.
- the treatment time is preferably 1 to 120 seconds.
- a method of bringing an aluminum hydroxide film into contact with an alkaline solution for example, a method of passing an aluminum base on which an aluminum hydroxide film is formed through a tank containing an alkaline solution, aluminum on which an aluminum hydroxide film is formed There is a method of immersing the substrate in a bath containing an alkaline solution, and a method of spraying the alkaline solution onto the surface (aluminum hydroxide film) of the aluminum substrate on which the aluminum hydroxide film is formed.
- the resin layer forming step is a step of forming a resin layer in which a part of each of the metal particles is embedded in one main surface of the metal foil using a composition containing a plurality of metal particles and a polymer component. is there.
- the through hole forming step 2 is a step of bringing a metal foil having a resin layer into contact with an etchant after the resin layer forming step to dissolve metal particles and a part of the metal foil to form a through hole in the metal foil.
- the resin layer removing step is a step of removing the resin layer after the through hole forming step 2 to produce an electromagnetic shielding member having a through hole.
- the metal foil is protected using a composition containing a polymer component on the main surface opposite to the surface on which the resin layer is formed. It is preferable to have a protective layer forming step of forming a layer.
- the through hole forming step 2 of dissolving the metal particles and a part of the metal foil to form through holes is performed, and thereafter the resin layer is removed.
- a metal foil having a plurality of fine through holes can be easily produced.
- the second production method is a resin layer forming step using a composition containing a plurality of metal particles and a polymer component, and as shown in FIG. 7, a plurality of metal particles on one main surface of the metal foil 12 A resin layer 14 in which a portion of each of 16 is embedded is formed.
- the surface on which the resin layer 14 of the metal foil 12 is formed is an optional protective layer forming step using a composition containing a polymer component. It is preferable to form a protective layer 18 on the opposite main surface.
- FIG. 8 the second manufacturing method, as shown in FIG.
- Through holes 5 are formed in the metal foil 12.
- the electromagnetic wave shielding member 10 including the metal foil 3 having the plurality of through holes 5 is formed by the resin layer removing step of removing the resin layer.
- the electromagnetic wave shield member 10 which has the some through-hole 5 by removing a resin layer and a protective layer by a resin layer removal process is carried out. It is formed.
- composition used in the resin layer forming step is a composition containing at least a plurality of metal particles and a polymer component.
- the metal particle contained in the above composition is not particularly limited as long as it is a particle containing a metal atom that dissolves in the etchant used in the through hole forming step 2 described later, but it is a particle composed of metal and / or metal compound Is preferred, and particles composed of metal are more preferred.
- the metal constituting the metal particles include, for example, aluminum, nickel, iron, copper, stainless steel, titanium, tantalum, molybdenum, niobium, zirconium, tungsten, beryllium, and alloys of these, These may be used alone or in combination of two or more.
- aluminum, nickel and copper are preferable, and aluminum and copper are more preferable.
- Examples of the metal compound constituting the metal particles include oxides, complex oxides, hydroxides, carbonates, sulfates, silicates, phosphates, nitrides, carbides, sulfides, and at least these. Two or more types of composites can be mentioned. Specifically, copper oxide, aluminum oxide, aluminum nitride, and aluminum borate etc. may be mentioned.
- the metal particles and the above-described metal foil contain the same metal atom from the viewpoint of recovering the etchant used in the through hole removing step described later and recycling the dissolved metal, etc. Is preferred.
- the shape of the metal particles is not particularly limited, but is preferably spherical, and more preferably closer to a true spherical shape.
- the average particle diameter of the metal particles is preferably 1 ⁇ m to 10 ⁇ m, and more preferably more than 2 ⁇ m and 6 ⁇ m or less, from the viewpoint of dispersibility in the composition and the like.
- the average particle diameter of the metal particles refers to the 50% cumulative diameter of the particle size distribution measured by a laser diffraction / scattering particle diameter measuring device (Microtrac MT 3000 manufactured by Nikkiso Co., Ltd.).
- the content of the metal particles is preferably 0.05 to 95% by mass, more preferably 1 to 50% by mass, and more preferably 3 to 25% by mass with respect to the total solid content contained in the composition. More preferably, it is%.
- the polymer component contained in the said composition is not specifically limited, A conventionally well-known polymer component can be used.
- the polymer component specifically, for example, epoxy resin, silicone resin, acrylic resin, urethane resin, ester resin, urethane acrylate resin, silicone acrylate resin, epoxy acrylate resin, ester acrylate A system resin, a polyamide system resin, a polyimide system resin, a polycarbonate system resin, and a phenol system resin etc. are mentioned, These may be used individually by 1 type and may use 2 or more types together.
- the polymer component is a phenolic resin because the desired through holes are easily obtained even when an acid solution is used as an etchant which is excellent in acid resistance and is used in the through hole forming step 2 described later. It is preferable that it is a resin material selected from the group consisting of acrylic resin and polyimide resin.
- the polymer component contained in the composition is a water-insoluble and alkaline water-soluble polymer (hereinafter, “alkaline water-soluble polymer It is preferable that it is a homopolymer which contains an acidic group in the main chain or side chain in the polymer, a copolymer thereof, or a mixture thereof.
- the alkaline water-soluble polymer one having an acidic group in the main chain and / or side chain of the polymer is preferable from the viewpoint of further facilitating the removal in the resin layer removing step described later.
- the acidic group include phenol group (-Ar-OH), sulfonamide group (-SO 2 NH-R), substituted sulfonamide group acid group (hereinafter referred to as "active imide group”) [-SO 2 NHCOR, -SO 2 NHSO 2 R, -CONHSO 2 R !, carboxyl group (-CO 2 H), sulfo group (-SO 3 H), and phosphonic group (-OPO 3 H 2 ) can be mentioned.
- Ar represents a divalent aryl linking group which may have a substituent
- R represents a hydrocarbon group which may have a substituent.
- alkaline water-soluble polymers having an acidic group alkaline water-soluble polymers having a phenol group, a carboxyl group, a sulfonamide group and an active imido group are preferable, and particularly an alkaline water-soluble polymer having a phenol group or a carboxyl group
- alkaline water-soluble polymer having an acidic group examples include the following.
- alkaline water-soluble polymers having a phenol group examples include one or more of phenol, o-cresol, m-cresol, p-cresol, and phenols such as xylenol, formaldehyde, and paraformaldehyde And novolak resins produced from aldehydes, and condensation polymers of pyrogallol and acetone. Furthermore, a copolymer obtained by copolymerizing a compound having a phenol group can also be mentioned. As a compound which has a phenol group, acrylamide which has a phenol group, methacrylamide, acrylic acid ester, methacrylic acid ester, or hydroxystyrene etc. are mentioned.
- novolak resins or copolymers of hydroxystyrene are preferable.
- Commercially available hydroxystyrene copolymers are Marukan Chemical Industries, Ltd., Maruka Linker M H-2, Marca Linker M S-4, Marca Linker M S-2, Marca Linker M S-1, Nippon Soda Co., Ltd. Company-made, VP-8000, and VP-15000 etc. can be mentioned.
- Examples of the alkaline water-soluble polymer having a sulfonamide group include a polymer composed of a minimum structural unit derived from a compound having a sulfonamide group as a main component.
- Examples of such a compound include a compound having one or more sulfonamide groups in which at least one hydrogen atom is bonded to a nitrogen atom, and one or more polymerizable unsaturated groups in the molecule.
- a low molecular weight compound having an acryloyl group, an allyl group or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in a molecule is preferable.
- m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, and / or N- (p-aminosulfonylphenyl) acrylamide and the like can be suitably used.
- alkaline water-soluble polymer having an active imide group examples include a polymer composed of a minimum structural unit derived from a compound having an active imide group as a main component.
- examples of such compounds include compounds having one or more active imide groups represented by the following structural formulas and one or more polymerizable unsaturated groups in the molecule.
- N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be suitably used.
- alkaline water-soluble polymer having a carboxyl group for example, a polymer having as a main constituent component a minimum structural unit derived from a compound having one or more carboxyl group and one or more polymerizable unsaturated groups in the molecule It can be mentioned. Specifically, polymers using unsaturated carboxylic acid compounds such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid can be mentioned.
- alkaline water-soluble polymer having a sulfo group for example, a polymer having as a main constitutional unit a minimum constitutional unit derived from a compound having one or more sulfo group and at least one polymerizable unsaturated group in the molecule It can be mentioned.
- alkaline water-soluble polymer having a phosphonic group for example, a polymer having as a main constituent component a minimum structural unit derived from a compound having one or more of a phosphonic group and a polymerizable unsaturated group in the molecule It can be mentioned.
- the minimum constituent unit having an acidic group which constitutes the alkaline water-soluble polymer does not have to be particularly limited to one type, and the minimum constitution unit having two or more types of minimum constituent units having the same acidic group or different acidic groups What co-polymerized 2 or more types of units can also be used.
- a graft copolymerization method As a method of copolymerization, a graft copolymerization method, a block copolymerization method, and / or a random copolymerization method which are conventionally known can be used.
- the copolymer preferably contains 10 mol% or more of a compound having an acidic group to be copolymerized in the copolymer, and more preferably 20 mol% or more.
- the compound when the compound is copolymerized to form a copolymer, another compound not containing an acidic group can also be used as the compound.
- the other compounds containing no acidic group include the compounds listed in the following (m1) to (m11).
- (M1) Acrylic acid esters having aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, and methacrylic acid esters.
- (M2) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, and N-dimethyl Alkyl acrylates such as aminoethyl acrylate.
- (M3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, and N-dimethyl Alkyl methacrylates such as aminoethyl methacrylate.
- (M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, and N- Acrylamide or methacrylamide such as ethyl-N-phenyl acrylamide.
- (M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
- (M6) Vinyl acetates such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate.
- (M7) Styrenes such as styrene, ⁇ -methylstyrene, methylstyrene and chloromethylstyrene.
- (M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
- Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
- (M10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, and methacrylonitrile and the like.
- (M11) unsaturated imides such as maleimide, N-acryloyl acrylamide, N-acetyl methacrylamide, N-propionyl methacrylamide, and N- (p-chlorobenzoyl) methacrylamide.
- the weight average molecular weight is 1.0 ⁇ 10 3 to 2.0 ⁇ 10 5 and the number average molecular weight is 5.0 ⁇ 10 2 to 1.0 Those in the range of ⁇ 10 5 are preferable. Further, those having a polydispersity (weight-average molecular weight / number-average molecular weight) of 1.1 to 10 are preferable.
- a copolymer When a copolymer is used as the polymer component, it constitutes the minimum structural unit derived from the compound having an acidic group, which constitutes the main chain and / or the side chain, and constitutes a part of the main chain and / or the side chain
- the compounding weight ratio with the other minimum structural unit not containing an acidic group is preferably in the range of 50:50 to 5:95, and more preferably in the range of 40:60 to 10:90.
- each of the above polymer components may be used, or two or more types of them may be used in combination, and in the range of 30 to 99% by mass with respect to the total solid content contained in the composition It is preferable to use it, more preferably in the range of 40 to 95% by mass, and still more preferably in the range of 50 to 90% by mass.
- the specific gravity of the metal particles is larger than the specific gravity of the polymer component with respect to the metal particles and the polymer component described above because the formation of the through holes is easy in the through hole forming step 2 described later. Is preferred. Specifically, the specific gravity of the metal particles is 1.5 or more, and the specific gravity of the polymer component is more preferably 0.9 or more and less than 1.5.
- the composition described above is a nonionic surfactant as described in JP-A-62-251740 and / or JP-A-3-208514, JP-A-59-121044, And / or an amphoteric surfactant as described in JP-A-4-13149 can be added.
- nonionic surfactant examples include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, and / or polyoxyethylene nonyl phenyl ether and the like.
- amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and / or N-tetradecyl- N, N-betaine type (for example, trade name Amogen K, manufactured by Dai-ichi Kogyo Co., Ltd.) and the like.
- the content in the case of containing the surfactant is preferably 0.01 to 10% by mass, and more preferably 0.05 to 5% by mass, with respect to the total solid content contained in the composition. preferable.
- a solvent can be added to the composition from the viewpoint of workability when forming a resin layer.
- the solvent include, for example, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl Acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, ⁇ -butyrolactone, toluene, water, etc. These may be used alone or in combination of two or more.
- coating a composition on metal foil and forming a resin layer is preferable.
- the coating method on the metal foil is not particularly limited. For example, bar coating method, slit coating method, ink jet method, spray method, roll coating method, spin coating method, cast coating method, slit and spin method, and transfer Methods such as law can be used.
- n the thickness of the resin layer to be formed
- r the average particle size of the metal particles contained in the composition
- the units of n and r both represent ⁇ m. .
- the thickness of the resin layer formed in the resin layer forming step from the viewpoint of the resistance to the etchant used in the through hole forming step 2 described later, the workability in the resin layer removing step described later, etc. is preferably 0.5 to 4 ⁇ m, and more preferably 1 ⁇ m to 2 ⁇ m.
- the average thickness of the resin layer refers to the average value of the thickness of any five points measured when the cross section was observed with an electron microscope by cutting using a microtome.
- the protective layer formation process of forming a protective layer using the composition containing a polymer component in the surface.
- a polymer component the same thing as the polymer component contained in the composition used at the resin layer formation process mentioned above is mentioned. That is, the protective layer formed in the optional protective layer forming step is the same layer as the above-described resin layer except that the above-described metal particles are not embedded, and the above-described metal is also used for the method of forming the protective layer.
- etchant As the etchant, if it is an etchant suitable for the metal species of the metal particles and the metal foil, it is possible to appropriately use a chemical solution of acid or alkali or the like.
- the acid include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hydrogen peroxide, and acetic acid.
- an alkali, caustic soda, caustic potash etc. are mentioned.
- alkali metal salt for example, alkali metal silicates such as sodium tasilicate, sodium silicate, potassium metasilicate and potassium silicate; sodium carbonate, alkali metal carbonates such as potassium carbonate; Alkali metal aluminates such as sodium acid and potassium aluminate; Alkali metal aldonates such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate and tribasic sodium phosphate And alkali metal hydrogen phosphates such as potassium triphosphate.
- inorganic salts such as iron (III) chloride and copper (II) chloride can also be used. In addition, these may be used alone or in combination of two or more.
- the processing for forming the through holes is performed by bringing a metal foil having a resin layer into contact with the above-mentioned etchant.
- the method of contact is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the immersion method is preferred.
- the immersion treatment time is preferably 15 seconds to 10 minutes, and more preferably 1 minute to 6 minutes.
- the liquid temperature of the etchant at the time of immersion is preferably 25 to 70 ° C., and more preferably 30 to 60 ° C.
- the resin layer removing step included in the manufacturing method of the present invention is a step of removing the resin layer after the above-described through hole forming step 2 to produce an electromagnetic shielding member having a through hole.
- the method for removing the resin layer is not particularly limited, but in the case of using the above-described alkaline water-soluble polymer as the polymer component, a method for dissolving and removing the resin layer using an alkaline aqueous solution is preferable.
- alkaline aqueous solution examples include, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate and inorganic alkalis such as aqueous ammonia; ethylamine, n-propylamine and the like Primary amines; diethylamine and secondary amines such as di-n-butylamine; triethylamine; tertiary amines such as methyl diethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; And Quaternary ammonium salts such as tetramethyl ammonium hydroxide and tetraethyl ammonium hydroxide; cyclic amines such as pyrrole and piheridine; and the like. These may be used alone or in combination of two or more. You may use together. An appropriate amount of alcohol and surfactant can be added to the above alkaline aqueous solution.
- the process of removing the resin layer is performed, for example, by bringing the metal foil having the resin layer after the through hole forming step 2 into contact with the above-described alkaline aqueous solution.
- the method for contacting is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the immersion method is preferred.
- the immersion time is preferably 5 seconds to 5 minutes, more preferably 10 seconds to 2 minutes.
- the alkaline aqueous solution at the time of immersion is preferably 25 to 60 ° C., and more preferably 30 to 50 ° C.
- the second manufacturing method preferably includes the step of applying an anticorrosive treatment. Further, the timing of applying the anticorrosion treatment is not particularly limited.
- the treatment may be applied to the metal foil used in the resin layer forming step, and the triazole or the like described later with respect to the alkaline aqueous solution in the resin layer removing step It may be a treatment to be added or a treatment to be applied after the resin layer removal step.
- the anticorrosive treatment for example, a treatment of immersing a metal foil in a solution having a pH of 5 to 8.5 in which at least a triazole is dissolved in a solvent to form an organic dielectric film can be mentioned.
- triazoles preferably include benzotriazole (BTA) and tolyltriazole (TTA).
- BTA benzotriazole
- TTA tolyltriazole
- various organic anticorrosives, thiazoles, imidazoles, mercaptans, and / or toluethanolamine, etc. can also be used.
- Water or an organic solvent (especially alcohol) can be suitably used as a solvent used for the anticorrosion treatment, but the uniformity of the organic dielectric film to be formed and the thickness control at the time of mass production can be easily performed, and it is simple. Furthermore, in view of the influence on the environment, etc., it is preferable that the water is mainly composed of deionized water.
- the dissolution concentration of the triazoles is appropriately determined in relation to the thickness of the organic dielectric film to be formed and the processing time, but generally, it may be about 0.005 to 1% by weight.
- the temperature of the solution may be room temperature, but if necessary, it may be used by heating.
- the immersion time of the metal foil in the solution is appropriately determined depending on the dissolution concentration of the triazole and the thickness of the organic dielectric film to be formed, but it may be usually about 0.5 to 30 seconds.
- Another specific example of the anticorrosion treatment is a method of immersing the metal foil in an aqueous solution formed by dissolving at least one member selected from the group of chromium trioxide, chromate, and dichromate in water.
- a method of forming an inorganic dielectric film mainly composed of a mixed oxide is a method of forming an inorganic dielectric film mainly composed of a mixed oxide.
- potassium chromate or sodium chromate is preferable as the chromate
- potassium dichromate or sodium dichromate is suitable as the dichromate.
- the dissolution concentration is usually set to 0.1 to 10% by mass, and the liquid temperature may be about room temperature to 60 ° C.
- the pH value of the aqueous solution is not particularly limited from the acidic region to the alkaline region, but is usually set to 1 to 12.
- the immersion time of metal foil is suitably selected by the thickness etc. of the inorganic dielectric film to form.
- a cut sheet metal foil may be used to perform processing of each process in a so-called sheet-fed type, or a long metal foil is conveyed in the longitudinal direction along a predetermined conveyance path.
- the process of each step may be performed, that is, so-called roll to roll (hereinafter, also referred to as “RtoR”) may be performed.
- RtoR refers to the resin layer forming process described above by each processing device disposed on the transport path while delivering the metal foil from a roll formed by winding a long metal foil and transporting it in the longitudinal direction. It is a manufacturing method which performs processing of a penetration hole formation process etc. continuously one by one successively, and winds a treated metal foil (namely, electromagnetic wave shield member) again in roll shape.
- Example 1 Preparation of an electromagnetic wave shield member>
- the surface of an aluminum base JIS H-4160, alloy number: 1085-H, aluminum purity: 99.85%
- the surface of an aluminum base (JIS H-4160, alloy number: 1085-H, aluminum purity: 99.85%) with an average thickness of 20 ⁇ m and a size of 200 mm ⁇ 300 mm is subjected to the treatment shown below to make an electromagnetic shielding member Made.
- A-1) Aluminum hydroxide film formation process (film formation process) Using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., electrolytic treatment is performed using the above aluminum substrate as a cathode, and aluminum hydroxide is applied to the aluminum substrate A film was formed. In addition, the electrolysis process was performed by direct-current power supply. The current density was 40 A / dm 2 and applied for 30 seconds. After the formation of the aluminum hydroxide film, washing with water by spraying was performed.
- Electrolytic dissolution treatment (through hole forming step 1) Next, using an electrolytic solution kept at 50 ° C. (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%), the aluminum base material is used as the anode, and the total electric quantity is 780 C / dm 2 Under the electrolytic treatment, through holes were formed in the aluminum base and the aluminum hydroxide film. In addition, the electrolysis process was performed by direct-current power supply. The current density was 25 A / dm 2 . After the formation of the through holes, the plate was rinsed with a spray and dried.
- Example 2 In place of the aluminum hydroxide film formation treatment shown in the above (a-1), an aluminum hydroxide film formation treatment shown in the following (a-2) is performed, and in place of the electrolytic dissolution treatment shown in the above (b-1), An electromagnetic wave shielding member was produced in the same manner as in Example 1 except that the following (b-2) electrolytic solution treatment (through hole forming step 1) was performed.
- A-2) Aluminum hydroxide film formation treatment (film formation process) Using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., electrolytic treatment is performed using the above aluminum substrate as a cathode, and aluminum hydroxide is applied to the aluminum substrate A film was formed. In addition, the electrolysis process was performed by direct-current power supply. The current density was 40 A / dm 2 and applied for 40 seconds. After the formation of the aluminum hydroxide film, washing with water by spraying was performed.
- Electrolytic dissolution treatment (through hole forming step 1) Then, using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., the aluminum base material is used as the anode and the total electric quantity is 300 C / dm 2 Under the electrolytic treatment, through holes were formed in the aluminum base and the aluminum hydroxide film. In addition, the electrolysis process was performed by direct-current power supply. The current density was 5 A / dm 2 . After the formation of the through holes, the plate was rinsed with a spray and dried.
- Example 3 An electromagnetic wave shielding member was produced in the same manner as in Example 1 except that the electrolytic dissolution treatment shown in (b-1) above was performed and the electrolytic dissolution treatment (through hole forming step 1) described below was performed. .
- Electrolytic dissolution treatment (through hole forming step 1) Next, using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., the aluminum base material is used as an anode, and the total electric quantity is 1000 C / dm 2 Under the electrolytic treatment, through holes were formed in the aluminum base and the aluminum hydroxide film. In addition, the electrolysis process was performed by direct-current power supply. The current density was 22 A / dm 2 . After the formation of the through holes, the plate was rinsed with a spray and dried.
- Example 4 As a metal foil, an aluminum substrate (JIS H-4160, alloy number: 1085-H, purity of aluminum: 99.85%) having an average thickness of 9.0 ⁇ m and a size of 200 mm ⁇ 300 mm is used. On the surface, PET with a thickness of 125 ⁇ m was laminated as a resin layer by the method described in Japanese Patent Application Laid-Open No. 2013-121673.
- JIS H-4160 alloy number: 1085-H, purity of aluminum: 99.85%
- an aluminum hydroxide film formation treatment shown in the above (a-1) is performed, and in place of the electrolytic dissolution treatment shown in the above (b-1)
- an electromagnetic wave shielding member was produced in the same manner as in Example 1 except that the following (b-4) electrolytic solution treatment (through hole forming step 1) was performed.
- A-3) Aluminum hydroxide film formation process (film formation process) Using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., electrolytic treatment is performed using the above aluminum substrate as a cathode, and aluminum hydroxide is applied to the aluminum substrate A film was formed. In addition, the electrolysis process was performed by direct-current power supply. The current density was 55 A / dm 2 and applied for 10 seconds.
- Electrolytic dissolution treatment (through hole forming step 1) Then, using the electrolytic solution (nitric acid concentration 1%, sulfuric acid concentration 0.2%, aluminum concentration 0.5%) kept at 50 ° C., the aluminum base material is used as the anode, and the total electric quantity is 400 C / dm 2 Under the electrolytic treatment, through holes were formed in the aluminum base and the aluminum hydroxide film. In addition, the electrolysis process was performed by direct-current power supply. The current density was 35 A / dm 2 . After the formation of the through holes, the plate was rinsed with a spray and dried.
- Example 5 ⁇ Preparation of an electromagnetic wave shield member>
- a copper foil JIS C 1100-H, electrolytic copper foil having an average thickness of 10 ⁇ m and a size of 200 mm ⁇ 300 mm was used.
- composition 1 for resin layer formation prepared to the following composition was coated on one side of a copper foil and dried to form a resin layer A1 having a thickness of about 1 ⁇ m.
- a composition prepared in the same ratio as the composition 1 for forming a resin layer described below is applied to the surface on the opposite side of the copper foil except that the copper particles are removed, dried, and a protective layer having a thickness of about 1 ⁇ m. B1 was formed.
- Comparative Example 1 An aluminum substrate was prepared according to the method described in WO 2008/078777. Specifically, for an aluminum foil (thickness: 20 ⁇ m) with uniform crystal orientation, the temperature of the hydrochloric acid electrolyte and the amount of electricity of the electrolytic treatment are adjusted to produce an aluminum substrate having through holes with an average opening diameter of 3 ⁇ m. did.
- Comparative Example 2 An aluminum substrate was prepared according to the method described in WO 2008/078777. Specifically, a pattern is formed on the surface of a hard aluminum foil (thickness: 20 ⁇ m) by resist printing, and a chemical etching treatment is performed with an alkaline processing solution to obtain aluminum having a through hole with an average opening diameter of 110 ⁇ m. A substrate was made.
- Comparative Example 3 An aluminum substrate was prepared according to the method described in WO 2008/078777. Specifically, through holes (average opening diameter: 300 ⁇ m) were mechanically formed by a punching die on a hard aluminum foil (thickness: 20 ⁇ m) to produce an aluminum base.
- the thickness of the metal foil, the average opening diameter of the through holes, and the average opening ratio of the electromagnetic wave shielding members manufactured in Examples 1 to 5 and Comparative Examples 1 to 3 were measured by the above-described method.
- Electromagnetic wave shield characteristics of GHz band of each of the electromagnetic wave shield members manufactured in Examples 1 to 5 and Comparative Examples 1 to 3, transmittance of electromagnetic waves from ultraviolet region to near infrared region, and transmittance of electromagnetic waves in middle infrared region was evaluated.
- Each of the electromagnetic wave shield members manufactured in Examples 1 to 5 and Comparative Examples 1 to 3 was attached to an opening 480 mm ⁇ 480 mm of the middle partition wall of the two-room shield room using an attachment as shown in FIG.
- the size of the exposed portion of the attached electromagnetic wave shield is 250 mm ⁇ 190 mm.
- the transmitting antenna and the receiving antenna were disposed at a distance of 1 m from each of the mid-spaced wall surfaces (an antenna spacing of 2 m) so that a shielding effect by a far-field plane wave could be obtained.
- a bilog antenna (CBL 6140A manufactured by SCHAFFNER) was used in the range of 30 NHz to 1000 MHz.
- a horn antenna (manufactured by RAVEN 96001) was used in the range of 1 GHz to 18 GHz.
- a Biconi antenna (manufactured by Fujitsu General EMC Laboratories Ltd.) was used.
- a horn antenna (9120D manufactured by SCHWARZBECK) was used.
- NA10MF3G2 manufactured by Noise Research Co., Ltd. was used in the range of 30 NHz to 1000 MHz.
- 83017A manufactured by Agilent was used in the range of 1 GHz to 18 GHz.
- a preamplifier a preamplifier manufactured by Stack Electronics Co., Ltd. was used in the range of 30 NHz to 1000 MHz.
- 8449B manufactured by HP was used in the range of 1 GHz to 18 GHz.
- Advantest Corporation R3770 was used as a network analyzer (NA).
- the receiving antenna is scanned over the range of ⁇ 240 mm (480 mm ⁇ 480 mm) center and the field strength is achieved by the Max Hold function. The highest level of was recorded.
- the electromagnetic wave shielding characteristics were determined from the intensity of the electromagnetic wave before passing through the electromagnetic wave shielding member and the maximum level of the intensity of the electromagnetic wave after passing through the electromagnetic wave shielding member.
- the electromagnetic wave shielding characteristics were set to an average value in the range of 1 GHz to 18 GHz with the state without the electromagnetic wave shielding member as a reference.
- ⁇ Transmittance of ultraviolet region to visible light region> The transmittance of the electromagnetic wave shield members manufactured in Examples 1 to 5 and Comparative Examples 1 to 3 was measured from the ultraviolet region to the visible light region. The transmittance was measured using SolidSpec-3700 manufactured by Shimadzu Corporation, and the average value was determined.
- ⁇ Transmittance of near infrared region> The transmittance in the near infrared region of each of the electromagnetic wave shielding members produced in Examples 1 to 5 and Comparative Examples 1 to 3 was measured. The transmittance was measured using a spectrometer V-7200 manufactured by JASCO Corporation, and the average value was determined.
- Comparative Example 1 has high shielding characteristics in the GHz band, but has no transparency in the ultraviolet to near infrared and mid infrared regions.
- Comparative Examples 2 and 3 although it has transmissivity in the ultraviolet region to the visible light region, the near infrared region, and the mid infrared region, the shield characteristics in the GHz band become low.
- the shielding characteristics in the GHz band can be 60 dB or more, and the transmittance from the ultraviolet region to the visible light region, the transmittance in the near infrared region, and the transmittance in the mid infrared region It can be seen that it can be secured. From the above, the effects of the present invention are clear.
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Abstract
Description
これに伴い、GHz帯の電磁波に対して高いシールド特性を有する電磁波シールド部材が求められている。
この特許文献1には、1GHz~8GHzの周波数帯域において、50dB以上の電磁波シールド特性を有することが記載されている([表1])。
しかしながら、GHz帯の電磁波に対しては、金網のような大きな貫通孔を有するシールド部材では高いシールド特性を得られないため、高いシールド特性と紫外領域、可視光領域、近赤外領域、および、中赤外領域の電磁波の透過性とを両立することができないという問題があった。
すなわち、以下の構成により上記目的を達成することができることを見出した。
貫通孔の平均開口径が1μm~100μm、平均開口率が1%~50%であり、
貫通孔の平均開口径が1μm以上、1.5μm未満において、
紫外領域から可視領域の電磁波の透過率が貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上であり、
前記貫通孔の平均開口径が1.5μm以上、5μm未満において、
紫外領域から可視領域において、貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
近赤外領域において、貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上であり、
貫通孔の平均開口径が5μm以上において、
紫外領域から近赤外領域の電磁波の透過率が、貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
中赤外領域において、貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上である電磁波シールド部材。
[2] 金属箔の厚みが5μm~1000μmである[1]に記載の電磁波シールド部材。
[3] 金属箔が、アルミニウム箔、銅箔、銀箔、金箔、白金箔、ステンレス箔、チタン箔、タンタル箔、モリブデン箔、ニオブ箔、ジルコニウム箔、タングステン箔、ベリリウム銅箔、燐青銅箔、黄銅箔、洋白箔、錫箔、鉛箔、亜鉛箔、半田箔、鉄箔、ニッケル箔、パーマロイ箔、ニクロム箔、42アロイ箔、コバール箔、モネル箔、インコネル箔、および、ハステロイ箔からなる群から選択される箔であり、または、この群から選択される箔と選択された箔とは異なる種類の金属とが積層されてなる箔である、[1]または[2]に記載の電磁波シールド部材。
以下に記載する構成要件の説明は、本発明の代表的な実施態様に基づいてなされることがあるが、本発明はそのような実施態様に限定されるものではない。
なお、本明細書において、「~」を用いて表される数値範囲は、「~」の前後に記載される数値を下限値および上限値として含む範囲を意味する。
本発明の電磁波シールド部材は、
厚み方向に貫通する貫通孔が複数形成された金属箔を備え、
貫通孔の平均開口径が1μm~100μm、平均開口率が1%~50%であり、
貫通孔の平均開口径が1μm以上、1.5μm未満において、
紫外領域から可視領域において、貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上であり、
貫通孔の平均開口径が1.5μm以上、5μm未満において、
紫外領域から可視領域の電磁波の透過率が、貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
近赤外領域において、貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上であり、
貫通孔の平均開口径が5μm以上において、
紫外領域から近赤外領域の電磁波の透過率が、貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
中赤外領域において、貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、平均開口率の10%以上である電磁波シールド部材。
次に、本発明の電磁波シールド部材の構成について、図1を用いて説明する。
図1および図2に示す電磁波シールド部材10は、金属箔3を厚み方向に貫通する複数の貫通孔5を有する。
これにより、GHz帯の電磁波に対して高いシールド特性を得られ、かつ、紫外領域、可視光領域、近赤外領域、および、中赤外領域の電磁波の透過性と確保することができる。
なお、倍率は、貫通孔を20個以上抽出できるSEM写真が得られるように上述した範囲の倍率を適宜選択することができる。また、開口径は、貫通孔部分の端部間の距離の最大値を測定した。すなわち、貫通孔の開口部の形状は略円形状に限定はされないので、開口部の形状が非円形状の場合には、貫通孔部分の端部間の距離の最大値を開口径とする。従って、例えば、2以上の貫通孔が一体化したような形状の貫通孔の場合にも、これを1つの貫通孔とみなし、貫通孔部分の端部間の距離の最大値を開口径とする。
上述した各波長域における電磁波の透過率は、該当する波長帯域における電磁波の透過率の平均値である。
本発明においては、1GHz~18GHzの周波数帯における電磁波シールド特性の平均値が60dB以上とすることができる。
ここで、電磁波シールド特性とは、電磁波シールド部材を通過する前の電界強度と電磁波シールド部材を通過した後の電界強度の比を対数で表したものである。
貫通孔の平均開口径を上記範囲とすることで、電磁波シールド特性をより好適にすることができる。また、電磁波シールド部材が多数の貫通孔を有するものとした場合でも、十分な引張強度を有するものとすることができる。
貫通孔の平均開口率を上記範囲とすることで、電磁波シールド特性をより好適にすることができる。また、電磁波シールド部材が多数の貫通孔を有するものとした場合でも、十分な引張強度を有するものとすることができる。
金属箔は、GHz帯の電磁波に対して高いシールド特性を有する箔であれば限定されないが、上述した平均開口径および平均開口率の貫通孔を容易に形成可能な金属および/または金属化合物から構成される箔であることが好ましく、金属から構成される箔がより好ましい。また、後述する貫通孔形成工程2で用いるエッチャントに対して溶解する金属原子を含む金属箔であることも好ましい。
金属箔としては、具体的には、例えば、アルミニウム箔、銅箔、銀箔、金箔、白金箔、ステンレス箔、チタン箔、タンタル箔、モリブデン箔、ニオブ箔、ジルコニウム箔、タングステン箔、ベリリウム銅箔、燐青銅箔、黄銅箔、洋白箔、錫箔、鉛箔、亜鉛箔、半田箔、鉄箔、ニッケル箔、パーマロイ箔、ニクロム箔、42アロイ箔、コバール箔、モネル箔、インコネル箔、および、ハステロイ箔などが挙げられる。
また、金属箔は上記種類の金属を含む異なる2種以上の金属が積層されたものであってもよい。
金属箔の積層手法は特に限定されないが、メッキまたはクラッド材であることが好ましい。メッキに用いる金属はエッチャントに対して溶解する金属原子を含む金属であるのが好ましく、金属であることが好ましい。メッキ種としては、例えば、ニッケル、クロム、コバルト、鉄、亜鉛、錫、銅、銀、金、白金、パラジウム、および、アルミニウム、などが挙げられる。
メッキの手法は特に問わず、無電解メッキ、電解メッキ、溶融メッキ、および、化成処理、などがいずれも用いられる。
また、上記金属箔に対してクラッド材を形成するのに用いる金属はエッチャントに対して溶解する金属原子を含む金属であるのが好ましく、金属であることが好ましい。金属種としては、例えば、上記金属箔に用いられる金属が挙げられる。
ここで、金属箔の平均厚みは、接触式膜厚測定計(デジタル電子マイクロメータ)を用いて、任意の5点を測定した厚みの平均値をいう。
金属箔としてアルミニウムを用いる場合のアルミニウムとしては、特に限定はされず、例えば、3000系(例えば、3003材など)、8000系(例えば、8021材など)等の公知のアルミニウム合金を用いることができる。
このようなアルミニウム合金としては、例えば、下記第1表に示す合金番号のアルミニウム合金を用いることができる。
次に、本発明の電磁波シールド部材の製造方法について説明する。
電磁波シールド部材の製造方法は、特に限定されないが、金属箔としてアルミニウム基材を用いる場合には、例えば、アルミニウム基材の少なくとも一方の表面に水酸化アルミニウム皮膜を形成する皮膜形成工程と、皮膜形成工程の後に、貫通孔形成処理を行って貫通孔を形成する貫通孔形成工程1と、貫通孔形成工程1の後に、水酸化アルミニウム皮膜を除去する皮膜除去工程と、皮膜除去工程の後に、貫通孔を有するアルミニウム基材の少なくとも一方の表面に樹脂層を形成する樹脂層形成工程とを有する方法などが挙げられる。
第1の製造方法は、図3~図6に示すように、アルミニウム基材1の両面に対して皮膜形成処理を施し、水酸化アルミニウム皮膜2を形成する皮膜形成工程(図3および図4)と、皮膜形成工程の後に電解溶解処理を施して貫通孔5を形成し、貫通孔を有するアルミニウム基材3および貫通孔を有する水酸化アルミニウム皮膜4を有する積層体を作製する貫通孔形成工程1(図4および図5)と、貫通孔形成工程1の後に、貫通孔を有する水酸化アルミニウム皮膜4を除去し、貫通孔を有するアルミニウム基材3を作製する皮膜除去工程(図5および図6)とを有する製造方法である。
本発明において、電磁波シールド部材の製造方法が有する皮膜形成工程は、アルミニウム基材の表面に皮膜形成処理を施し、水酸化アルミニウム皮膜を形成する工程である。
上記皮膜形成処理は特に限定されず、例えば、従来公知の水酸化アルミニウム皮膜の形成処理と同様の処理を施すことができる。
皮膜形成処理としては、例えば、特開2011-201123号公報の[0013]~[0026]段落に記載された条件や装置を適宜採用することができる。
硝酸または塩酸を含む電解液中で電気化学的処理を行う場合には、アルミニウム基材と対極との間に直流を印加してもよく、交流を印加してもよい。アルミニウム基材に直流を印加する場合においては、電流密度は、1~60A/dm2であるのが好ましく、5~50A/dm2であるのがより好ましい。連続的に電気化学的処理を行う場合には、アルミニウム基材に、電解液を介して給電する液給電方式により行うのが好ましい。
貫通孔形成工程1は、皮膜形成工程の後に電解溶解処理を施し、貫通孔を形成する工程である。
上記電解溶解処理は特に限定されず、直流または交流を用い、酸性溶液を電解液に用いることができる。中でも、硝酸および塩酸の少なくとも一方の酸を用いて電気化学処理を行うのが好ましく、これらの酸に、硫酸、燐酸およびシュウ酸の少なくとも1以上の酸を加えた混酸を用いて電気化学的処理を行うのがより好ましい。
ここで、「主体とする」とは、水溶液中に主体となる成分が、水溶液に添加した成分全体に対して、30質量%以上、好ましくは50質量%以上含まれていることをいう。以下、他の成分においても同様である。
また、上記酸を主体とする水溶液には、鉄、銅、マンガン、ニッケル、チタン、マグネシウム、及び/又は、シリカ等のアルミニウム合金中に含まれる金属が溶解していてもよい。好ましくは、酸の濃度0.1~2質量%の水溶液にアルミニウムイオンが1~100g/Lとなるように、塩化アルミニウム、硝酸アルミニウム、及び/又は、硫酸アルミニウム等を添加した液を用いることが好ましい。
本発明においては、硝酸を主体とする電解液を用いた電気化学的溶解処理(以下、「硝酸溶解処理」とも略す。)により、容易に、平均開口径が1μm以上100μm以下となる貫通孔を形成することができる。
ここで、硝酸溶解処理は、貫通孔形成の溶解ポイントを制御しやすい理由から、直流電流を用い、平均電流密度を5A/dm2以上とし、かつ、電気量を50C/dm2以上とする条件で施す電解処理であるのが好ましい。なお、平均電流密度は100A/dm2以下であるのが好ましく、電気量は10000C/dm2以下であるのが好ましい。
また、硝酸電解における電解液の濃度や温度は特に限定されず、高濃度、例えば、硝酸濃度15~35質量%の硝酸電解液を用いて30~60℃で電解を行ったり、硝酸濃度0.7~2質量%の硝酸電解液を用いて高温、例えば、80℃以上で電解を行ったりすることができる。
また、上記硝酸電解液に濃度0.1~50質量%の硫酸、シュウ酸、および、燐酸の少なくとも1つを混ぜた電解液を用いて電解を行うことができる。
本発明においては、塩酸を主体とする電解液を用いた電気化学的溶解処理(以下、「塩酸溶解処理」とも略す。)によっても、容易に、平均開口径が1μm以上100μm以下となる貫通孔を形成することができる。
ここで、塩酸溶解処理は、貫通孔形成の溶解ポイントを制御しやすい理由から、直流電流を用い、平均電流密度を5A/dm2以上とし、かつ、電気量を50C/dm2以上とする条件で施す電解処理であるであるのが好ましい。なお、平均電流密度は100A/dm2以下であるのが好ましく、電気量は10000C/dm2以下であるのが好ましい。
また、塩酸電解における電解液の濃度や温度は特に限定されず、高濃度、例えば、塩酸濃度10~35質量%の塩酸電解液を用いて30~60℃で電解を行ったり、塩酸濃度0.7~2質量%の塩酸電解液を用いて高温、例えば、80℃以上で電解を行ったりすることができる。
また、上記塩酸電解液に濃度0.1~50質量%の硫酸、シュウ酸、および、燐酸の少なくとも1つを混ぜた電解液を用いて電解を行うことができる。
皮膜除去工程は、化学的溶解処理を行って水酸化アルミニウム皮膜を除去する工程である。
上記皮膜除去工程は、例えば、後述する酸エッチング処理、及び/又は、アルカリエッチング処理を施すことにより水酸化アルミニウム皮膜を除去することができる。
上記溶解処理は、アルミニウムよりも水酸化アルミニウムを優先的に溶解させる溶液(以下、「水酸化アルミニウム溶解液」という。)を用いて水酸化アルミニウム皮膜を溶解させる処理である。
ジルコニウム系化合物としては、例えば、フッ化ジルコンアンモニウム、フッ化ジルコニウム、および、塩化ジルコニウムが挙げられる。
チタン化合物としては、例えば、酸化チタン、および、硫化チタンが挙げられる。
リチウム塩としては、例えば、フッ化リチウム、および、塩化リチウムが挙げられる。
セリウム塩としては、例えば、フッ化セリウム、および、塩化セリウムが挙げられる。
マグネシウム塩としては、例えば、硫化マグネシウムが挙げられる。
マンガン化合物としては、例えば、過マンガン酸ナトリウム、および、過マンガン酸カルシウムが挙げられる。
モリブデン化合物としては、例えば、モリブデン酸ナトリウムが挙げられる。
マグネシウム化合物としては、例えば、フッ化マグネシウム・五水和物が挙げられる。
バリウム化合物としては、例えば、酸化バリウム、酢酸バリウム、炭酸バリウム、塩素酸バリウム、塩化バリウム、フッ化バリウム、ヨウ化バリウム、乳酸バリウム、シュウ酸バリウム、過塩素酸バリウム、セレン酸バリウム、亜セレン酸バリウム、ステアリン酸バリウム、亜硫酸バリウム、チタン酸バリウム、水酸化バリウム、および、硝酸バリウム、あるいはこれらの水和物等が挙げられる。
上記バリウム化合物の中でも、酸化バリウム、酢酸バリウム、および、炭酸バリウムが好ましく、酸化バリウムが特に好ましい。
ハロゲン単体としては、例えば、塩素、フッ素、および、臭素が挙げられる。
酸濃度としては、0.01mol/L以上であるのが好ましく、0.05mol/L以上であるのがより好ましく、0.1mol/L以上であるのが更に好ましい。上限は特にないが、一般的には10mol/L以下であるのが好ましく、5mol/L以下であるのがより好ましい。
浸せき処理の時間は、10分以上であるのが好ましく、1時間以上であるのがより好ましく、3時間以上、5時間以上であるのが更に好ましい。
アルカリエッチング処理は、上記水酸化アルミニウム皮膜をアルカリ溶液に接触させることにより、表層を溶解させる処理である。
樹脂層形成工程は、金属箔の一方の主面に、複数の金属粒子および重合体成分を含有する組成物を用いて、金属粒子の各々の一部が埋設された樹脂層を形成する工程である。
貫通孔形成工程2は、樹脂層形成工程の後に、樹脂層を有する金属箔をエッチャントに接触させて金属粒子および金属箔の一部を溶解し、金属箔に貫通孔を形成する工程である。
樹脂層除去工程は、貫通孔形成工程2の後に、樹脂層を除去し、貫通孔を有する電磁波シールド部材を作製する工程である。
第2の製造方法は、複数の金属粒子および重合体成分を含有する組成物を用いた樹脂層形成工程により、図7に示すように、金属箔12の一方の主面に、複数の金属粒子16の各々の一部が埋設された樹脂層14が形成される。
また、第2の製造方法は、重合体成分を含有する組成物を用いた任意の保護層形成工程により、図8に示すように、金属箔12の、樹脂層14が形成される面とは反対側の主面に、保護層18を形成することが好ましい。
また、第2の製造方法は、樹脂層を有する金属箔をエッチャントに接触させて金属粒子および金属箔の一部を溶解する貫通孔形成工程2により、図9に示すように、樹脂層14および金属箔12に貫通孔5が形成される。
また、第2の製造方法は、樹脂層を除去する樹脂層除去工程により、図10に示すように、複数の貫通孔5を有する金属箔3を備える電磁波シールド部材10が形成される。なお、保護層形成工程を有している場合、図10に示すように、樹脂層除去工程により、樹脂層および保護層が除去されることにより、複数の貫通孔5を有する電磁波シールド部材10が形成される。
第2の製造方法が有する樹脂層形成工程は、金属箔の一方の主面に、複数の金属粒子および重合体成分を含有する組成物を用いて、金属粒子の各々の一部が埋設された樹脂層を形成する工程である。
樹脂層形成工程で用いる組成物は、少なくとも複数の金属粒子および重合体成分を含有する組成物である。
上記組成物に含まれる金属粒子は、後述する貫通孔形成工程2で用いるエッチャントに対して溶解する金属原子を含む粒子であれば特に限定されないが、金属および/または金属化合物から構成される粒子であることが好ましく、金属から構成される粒子がより好ましい。
これらのうち、アルミニウム、ニッケル、および、銅であることが好ましく、アルミニウム、および、銅であることがより好ましい。
また、金属粒子の平均粒子径は、組成物における分散性などの観点から、1μm~10μmであることが好ましく、2μm超6μm以下であることがより好ましい。
ここで、金属粒子の平均粒子径は、レーザー回折・散乱式粒子径測定装置(日機装(株)製マイクロトラックMT3000)で測定される粒度分布の累積50%径をいう。
上記組成物に含まれる重合体成分は特に限定されず、従来公知の重合体成分を用いることができる。
重合体成分としては、具体的には、例えば、エポキシ系樹脂、シリコーン系樹脂、アクリル系樹脂、ウレタン系樹脂、エステル系樹脂、ウレタンアクリレート系樹脂、シリコーンアクリレート系樹脂、エポキシアクリレート系樹脂、エステルアクリレート系樹脂、ポリアミド系樹脂、ポリイミド系樹脂、ポリカーボネート系樹脂、および、フェノール系樹脂などが挙げられ、これらを1種単独で用いてもよく、2種以上を併用してもよい。
これらのうち、耐酸性に優れ、後述する貫通孔形成工程2で用いるエッチャントとして酸性溶液を用いた場合にも、所望の貫通孔が得られやすくなる理由から、重合体成分が、フェノール系樹脂、アクリル系樹脂およびポリイミド系樹脂からなる群から選択される樹脂材料であることが好ましい。
酸性基の具体例としては、フェノール基(-Ar-OH)、スルホンアミド基(-SO2NH-R)、置換スルホンアミド系酸基(以下、「活性イミド基」という。)〔-SO2NHCOR、-SO2NHSO2R、-CONHSO2R〕、カルボキシル基(-CO2H)、スルホ基(-SO3H)、および、ホスホン基(-OPO3H2)が挙げられる。
なお、Arは置換基を有していてもよい2価のアリール連結基を表し、Rは、置換基を有していてもよい炭化水素基を表す。
特に、m-アミノスルホニルフェニルメタクリレート、N-(p-アミノスルホニルフェニル)メタクリルアミド、及び/又は、N-(p-アミノスルホニルフェニル)アクリルアミド等を好適に使用することができる。
スルホ基を有するアルカリ水可溶性高分子としては、例えば、スルホ基と、重合可能な不飽和基と、を分子内にそれぞれ1以上有する化合物に由来する最小構成単位を主要構成単位とする重合体を挙げることができる。
ホスホン基を有するアルカリ水可溶性高分子としては、例えば、ホスホン基と、重合可能な不飽和基と、を分子内にそれぞれ1以上有する化合物に由来する最小構成単位を主要構成成分とする重合体を挙げることができる。
(m2)アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ブチル、アクリル酸アミル、アクリル酸ヘキシル、アクリル酸オクチル、アクリル酸ベンジル、アクリル酸-2-クロロエチル、グリシジルアクリレート、および、N-ジメチルアミノエチルアクリレート等のアルキルアクリレート。
(m3)メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ブチル、メタクリル酸アミル、メタクリル酸ヘキシル、メタクリル酸シクロヘキシル、メタクリル酸ベンジル、メタクリル酸-2-クロロエチル、グリシジルメタクリレート、および、N-ジメチルアミノエチルメタクリレート等のアルキルメタクリレート。
(m4)アクリルアミド、メタクリルアミド、N-メチロールアクリルアミド、N-エチルアクリルアミド、N-ヘキシルメタクリルアミド、N-シクロヘキシルアクリルアミド、N-ヒドロキシエチルアクリルアミド、N-フェニルアクリルアミド、N-ニトロフェニルアクリルアミド、および、N-エチル-N-フェニルアクリルアミド等のアクリルアミドもしくはメタクリルアミド。
(m5)エチルビニルエーテル、2-クロロエチルビニルエーテル、ヒドロキシエチルビニルエーテル、プロピルビニルエーテル、ブチルビニルエーテル、オクチルビニルエーテル、および、フェニルビニルエーテル等のビニルエーテル類。
(m6)ビニルアセテート、ビニルクロロアセテート、ビニルブチレート、および、安息香酸ビニル等のビニルエステル類。
(m7)スチレン、α-メチルスチレン、メチルスチレン、および、クロロメチルスチレン等のスチレン類。
(m8)メチルビニルケトン、エチルビニルケトン、プロピルビニルケトン、および、フェニルビニルケトン等のビニルケトン類。
(m9)エチレン、プロピレン、イソブチレン、ブタジエン、および、イソプレン等のオレフィン類。
(m10)N-ビニルピロリドン、N-ビニルカルバゾール、4-ビニルピリジン、アクリロニトリル、および、メタクリロニトリル等。
(m11)マレイミド、N-アクリロイルアクリルアミド、N-アセチルメタクリルアミド、N-プロピオニルメタクリルアミド、および、N-(p-クロロベンゾイル)メタクリルアミド等の不飽和イミド。
上記組成物は、塗布性の観点から、特開昭62-251740号、及び/又は、特開平3-208514号に記載されているような非イオン界面活性剤、特開昭59-121044号、及び/又は、特開平4-13149号に記載されているような両性界面活性剤を添加することができる。
上記組成物は、樹脂層を形成する際の作業性の観点から、溶媒を添加することができる。
溶媒としては、具体的には、例えば、エチレンジクロライド、シクロヘキサノン、メチルエチルケトン、メタノール、エタノール、プロパノール、エチレングリコールモノメチルエーテル、1-メトキシ-2-プロパノール、2-メトキシエチルアセテート、1-メトキシ-2-プロピルアセテート、ジメトキシエタン、乳酸メチル、乳酸エチル、N,N-ジメチルアセトアミド、N,N-ジメチルホルムアミド、テトラメチルウレア、N-メチルピロリドン、ジメチルスルホキシド、スルホラン、γ-ブチロラクトン、トルエン、および、水等が挙げられ、これらを1種単独で用いてもよく、2種以上を併用してもよい。
上述した組成物を用いた樹脂層の形成方法は特に限定されないが、金属箔上に組成物を塗布して樹脂層を形成する方法が好ましい。
金属箔上への塗布方法は特に限定されず、例えば、バーコート法、スリットコート法、インクジェット法、スプレー法、ロールコート法、回転塗布法、流延塗布法、スリットアンドスピン法、および、転写法等の方法を用いることができる。
n<r ・・・(1)
ここで、式(1)中、nは、形成される樹脂層の厚みを表し、rは、組成物に含まれる金属粒子の平均粒子径を表し、nおよびrの単位はいずれもμmを表す。
ここで、樹脂層の平均厚みは、ミクロトームを用いて切削し、断面を電子顕微鏡で観察した際に測定された任意の5点の厚みの平均値をいう。
更に、第2の製造方法においては、後述する貫通孔形成工程2における作業性の観点から、貫通孔形成工程2の前に、金属箔の、樹脂層が形成される面とは反対側の主面に、重合体成分を含有する組成物を用いて保護層を形成する保護層形成工程を有していることが好ましい。
ここで、重合体成分としては、上述した樹脂層形成工程で用いる組成物に含まれる重合体成分と同一のものが挙げられる。すなわち、任意の保護層形成工程で形成される保護層は、上述した金属粒子が埋設されていない以外は、上述した樹脂層と同様の層であり、保護層の形成方法についても、上述した金属粒子を用いない以外は、上述した樹脂層と同様の方法で形成することができる。
なお、保護層形成工程を有する場合、貫通孔形成工程2の前の工程であれば、特に順序は限定されず、上述した樹脂層形成工程の前後または同時に行う工程であってもよい。
第2の製造方法が有する貫通孔形成工程2は、上述した樹脂層形成工程の後に、樹脂層を有する金属箔をエッチャントに接触させて金属粒子および金属箔の一部を溶解し、金属箔に貫通孔を形成する工程であり、いわゆる化学エッチング処理により金属箔に貫通孔を形成する工程である。
エッチャントとしては、金属粒子および金属箔の金属種に適したエッチャントであれば、酸またはアルカリの化学溶液などを適宜用いることが可能である。
酸の例としては、塩酸、硫酸、硝酸、フッ酸、過酸化水素、および、酢酸などが挙げられる。
また、アルカリの例としては、カセイソーダ、および、カセイカリなどが挙げられる。
また、アルカリ金属塩としては、例えば、タケイ酸ソーダ、ケイ酸ソーダ、メタケイ酸カリ、および、ケイ酸カリ等のアルカリ金属ケイ酸塩;炭酸ソーダ、および、炭酸カリ等のアルカリ金属炭酸塩;アルミン酸ソーダ、および、アルミン酸カリ等のアルカリ金属アルミン酸塩;グルコン酸ソーダ、および、グルコン酸カリ等のアルカリ金属アルドン酸塩;第二リン酸ソーダ、第二リン酸カリ、第三リン酸ソーダ、および、第三リン酸カリ等のアルカリ金属リン酸水素塩が挙げられる。
また、塩化鉄(III)、および、塩化銅(II)などの無機塩も用いることができる。
また、これらは1種類でも、2種類以上混合して使用してもよい。
貫通孔を形成する処理は、樹脂層を有する金属箔を上述したエッチャントに接触させることにより行う。
接触させる方法は特に限定されず、例えば、浸せき法、スプレー法が挙げられる。中でも、浸せき法が好ましい。
浸せき処理の時間は、15秒~10分であることが好ましく、1分~6分であることがより好ましい。
また、浸漬させる際のエッチャントの液温は、25~70℃であることが好ましく、30~60℃であることがより好ましい。
本発明の製造方法が有する樹脂層除去工程は、上述した貫通孔形成工程2の後に、樹脂層を除去し、貫通孔を有する電磁波シールド部材を作製する工程である。
樹脂層を除去する方法は特に限定されないが、重合体成分として上述したアルカリ水可溶性高分子を用いる場合には、アルカリ性水溶液を用いて樹脂層を溶解して除去する方法が好ましい。
アルカリ性水溶液としては、具体的には、例えば、水酸化ナトリウム、水酸化カリウム、炭酸ナトリウム、ケイ酸ナトリウム、メタケイ酸ナトリウム、および、アンモニア水等の無機アルカリ類;エチルアミン、および、n-プロピルアミン等の第一アミン類;ジエチルアミン、および、ジ-n-ブチルアミン等の第二アミン類;トリエチルアミン、および、メチルジエチルアミン等の第三アミン類;ジメチルエタノールアミン、および、トリエタノールアミン等のアルコールアミン類;テトラメチルアンモニウムヒドロキシド、および、テトラエチルアンモニウムヒドロキシド等の第四級アンモニウム塩;ピロール、および、ピヘリジン等の環状アミン類;などが挙げられ、これらを1種単独で用いてもよく、2種以上を併用してもよい。
なお、上記アルカリ性水溶液に、アルコール類、界面活性剤を適当量添加して使用することもできる。
樹脂層を除去する処理は、例えば、貫通孔形成工程2後の樹脂層を有する金属箔を上述したアルカリ性水溶液に接触させることにより行う。
接触させる方法は特に限定されず、例えば、浸せき法、および、スプレー法等が挙げられる。中でも、浸せき法が好ましい。
浸せき処理の時間は、5秒~5分であることが好ましく、10秒~2分であることがより好ましい。
また、浸漬させる際のアルカリ性水溶液は、25~60℃であることが好ましく、30~50℃であることがより好ましい。
第2の製造方法は、防食処理を施す工程を有していることが好ましい。
また、防食処理を施すタイミングは特に限定されず、例えば、樹脂層形成工程で用いる金属箔に対して施す処理であってもよく、樹脂層除去工程においてアルカリ性水溶液に対して後述するトリアゾール類などを添加する処理であってもよく、樹脂層除去工程後に施す処理であってもよい。
また、トリアゾール類とともに、各種の有機防錆材、チアゾール類、イミダゾール類、メルカプタン類、及び/又は、トルエタノールアミンなども使用することができる。
また、溶液の温度は室温であればよいが、必要に応じては加温して使用してもよい。
また、金属箔の浸漬時間は、形成する無機誘電体皮膜の厚みなどにより適宜に選定される。
本発明においては、カットシート状の金属箔を用いて、いわゆる枚葉式で各工程の処理を施すものであってもよいし、長尺な金属箔を、所定の搬送経路で長手方向に搬送しつつ各工程の処理を施す、いわゆるロール・ツー・ロール(Roll to Roll)(以下、「RtoR」ともいう。)による処理を行うものであってもよい。
本発明におけるRtoRとは、長尺な金属箔を巻回してなるロールから金属箔を送り出して、長手方向に搬送しつつ、搬送経路上に配置された各処理装置によって、上述した樹脂層形成工程、貫通孔形成工程などの処理を連続的に順次、行い、処理済の金属箔(すなわち、電磁波シールド部材)を、再度、ロール状に巻回する製造方法である。
<電磁波シールド部材の作製>
平均厚さ20μm、大きさ200mm×300mmのアルミニウム基材(JIS H-4160、合金番号:1085-H、アルミニウム純度:99.85%)の表面に、以下に示す処理を施し、電磁波シールド部材を作製した。
50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、上記アルミニウム基材を陰極として電解処理を施し、アルミニウム基材に水酸化アルミニウム皮膜を形成した。なお、電解処理は直流電源で行った。電流密度は、40A/dm2とし、30秒間印加した。
水酸化アルミニウム皮膜形成後、スプレーによる水洗を行った。
次いで、50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、アルミニウム基材を陽極として、電気量総和が780C/dm2の条件下で電解処理を施し、アルミニウム基材及び水酸化アルミニウム皮膜に貫通孔を形成した。なお、電解処理は直流電源で行った。電流密度は25A/dm2とした。
貫通孔の形成後、スプレーによる水洗を行い、乾燥させた。
次いで、電解溶解処理後のアルミニウム基材を、水酸化ナトリウム濃度5質量%、アルミニウムイオン濃度0.5質量%の水溶液(液温35℃)中に30秒間浸漬した後、硫酸濃度30%、アルミニウムイオン濃度0.5質量%の水溶液(液温50℃)中に20秒間浸漬させることにより、水酸化アルミニウム皮膜を溶解し除去した。
アルミニウム皮膜の除去後、スプレーによる水洗を行い、乾燥させることにより複数の貫通孔を有する電磁波シールド部材を作製した。
上記(a-1)に示す水酸化アルミニウム皮膜形成処理に代えて、下記(a-2)に示す水酸化アルミニウム皮膜形成処理を施し、上記(b-1)に示す電解溶解処理に代えて、下記(b-2)電解溶解処理(貫通孔形成工程1)を施した以外は、実施例1と同様にして電磁波シールド部材を作製した。
50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、上記アルミニウム基材を陰極として電解処理を施し、アルミニウム基材に水酸化アルミニウム皮膜を形成した。なお、電解処理は直流電源で行った。電流密度は、40A/dm2とし、40秒間印加した。
水酸化アルミニウム皮膜形成後、スプレーによる水洗を行った。
次いで、50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、アルミニウム基材を陽極として、電気量総和が300C/dm2の条件下で電解処理を施し、アルミニウム基材及び水酸化アルミニウム皮膜に貫通孔を形成した。なお、電解処理は直流電源で行った。電流密度は5A/dm2とした。
貫通孔の形成後、スプレーによる水洗を行い、乾燥させた。
上記(b-1)に示す電解溶解処理に代えて、下記(b-3)電解溶解処理(貫通孔形成工程1)を施した以外は、実施例1と同様にして電磁波シールド部材を作製した。
次いで、50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、アルミニウム基材を陽極として、電気量総和が1000C/dm2の条件下で電解処理を施し、アルミニウム基材及び水酸化アルミニウム皮膜に貫通孔を形成した。なお、電解処理は直流電源で行った。電流密度は22A/dm2とした。
貫通孔の形成後、スプレーによる水洗を行い、乾燥させた。
金属箔として、平均厚さ9.0μm、大きさ200mm×300mmのアルミニウム基材(JIS H-4160、合金番号:1085-H、アルミニウム純度:99.85%)を用い、アルミニウム基材の一方の表面に、特開2013-121673号公報に記載された方法で、厚さ125μmのPETを樹脂層としてラミネートした。その後、上記(a-1)に示す水酸化アルミニウム皮膜形成処理に代えて、下記(a-3)に示す水酸化アルミニウム皮膜形成処理を施し、上記(b-1)に示す電解溶解処理に代えて、下記(b-4)電解溶解処理(貫通孔形成工程1)を施した以外は、実施例1と同様にして電磁波シールド部材を作製した。
50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、上記アルミニウム基材を陰極として電解処理を施し、アルミニウム基材に水酸化アルミニウム皮膜を形成した。なお、電解処理は直流電源で行った。電流密度は、55A/dm2とし、10秒間印加した。
次いで、50℃に保温した電解液(硝酸濃度1%、硫酸濃度0.2%、アルミニウム濃度0.5%)を用いて、アルミニウム基材を陽極として、電気量総和が400C/dm2の条件下で電解処理を施し、アルミニウム基材及び水酸化アルミニウム皮膜に貫通孔を形成した。なお、電解処理は直流電源で行った。電流密度は35A/dm2とした。
貫通孔の形成後、スプレーによる水洗を行い、乾燥させた。
<電磁波シールド部材の作製>
金属箔として、平均厚さ10μm、大きさ200mm×300mmの銅箔(JIS C 1100-H、電解銅箔)を用いた。
銅箔上の片面に、下記組成に調製した樹脂層形成用組成物1を塗布し、乾燥させ、厚みが約1μmの樹脂層A1を形成した。
また、銅箔の逆側の面には、銅粒子を除いた以外は下記樹脂層形成用組成物1と同様の比率で調製した組成物を塗布し、乾燥させ、厚みが約1μmの保護層B1を形成した。
―――――――――――――――――――――――――――――――――
樹脂層形成用組成物1
―――――――――――――――――――――――――――――――――
・m,p-クレゾールノボラック
(m/p比=6/4、重量平均分子量4100) 1.2g
・HXR-Cu(銅粒子、平均粒子径:5.0μm、
日本アトマイズ加工(株)社製) 0.4g
・メガファックF-780-F(界面活性剤、DIC(株)製)0.1g
・メチルエチルケトン 1.0g
・1-メトキシ-2-プロパノール 5.0g
―――――――――――――――――――――――――――――――――
次いで、40℃に保温したエッチャント〔塩化鉄(III)濃度:30質量%、塩酸濃度:3.65質量%〕に、樹脂層A1および保護層B1を有する銅箔を3分間浸漬し、その後、スプレーによる水洗を行い、乾燥させることにより、貫通孔を形成した。
次いで、貫通孔形成後の銅箔を、液温50℃のアルカリ性水溶液(水酸化ナトリウム濃度:0.4質量%)中に120秒間浸漬させることにより、樹脂層A1および保護層B1を溶解し、除去した。
その後、スプレーによる水洗を行い、乾燥させることにより、貫通孔を有する電磁波シールド部材を作製した。
国際公開第2008/078777号に記載された方法に従い、アルミニウム基材を作製した。
具体的には、結晶配向を揃えたアルミニウム箔(厚み:20μm)に対して、塩酸電解液の温度と電解処理の電気量を調整し、平均開口径3μmの貫通孔を有するアルミニウム基材を作製した。
国際公開第2008/078777号に記載された方法に従い、アルミニウム基材を作製した。
具体的には、硬質アルミニウム箔(厚み:20μm)の表面に、レジスト印刷にてパターンを形成し、アルカリ処理液で化学的なエッチング処理を施すことにより、平均開口径110μmの貫通孔を有するアルミニウム基材を作製した。
国際公開第2008/078777号に記載された方法に従い、アルミニウム基材を作製した。
具体的には、硬質アルミニウム箔(厚み:20μm)に対してパンチングダイにより機械的に貫通孔(平均開口径:300μm)を形成し、アルミニウム基材を作製した。
実施例1~5および比較例1~3で作製した各電磁波シールド部材のGHz帯の電磁波シールド特性、紫外領域から近赤外領域の電磁波の透過率、および、中赤外領域の電磁波の透過率を評価した。
実施例1~5および比較例1~3で作製した各電磁波シールド部材を、図11に示すように、2室シールドルームの中間隔壁の開口480mm×480mmにアタッチメントを用いて取り付けた。なお、取り付けられた電磁波シールドの表出部の大きさは250mm×190mmとなる。
また、大略遠方界平面波によるシールド効果が得られる様に、中間隔壁面より各1mの距離(アンテナ間隔2m)に送信アンテナおよび受信アンテナを配置した。
受信アンテナとしては、30NHz~1000MHzの範囲は、バイコニアンテナ(株式会社富士通ゼネラルEMC研究所製)を用いた。また、1GHz~18GHzの範囲は、ホーンアンテナ(SCHWARZBECK社製 9120D)を用いた。
パワーアンプとしては、30NHz~1000MHzの範囲は、株式会社ノイズ研究所製 NA10MF3G2を用いた。また、1GHz~18GHzの範囲はAgilent社製 83017Aを用いた。
プリアンプとしては、30NHz~1000MHzの範囲は、スタック電子株式会社製のプリアンプを用いた。また、1GHz~18GHzの範囲はHP社製 8449Bを用いた。
ネットワークアナライザ(NA)としては、株式会社アドバンテスト製 R3770を用いた。
実施例1~5および比較例1~3で作製した各電磁波シールド部材の紫外領域から可視光領域の透過率を測定した。
透過率は、株式会社島津製作所製 SolidSpec-3700を用いて透過率を測定し、平均値を求めた。
実施例1~5および比較例1~3で作製した各電磁波シールド部材の近赤外領域の透過率を測定した。
透過率は、日本分光株式会社製分光器V-7200を用いて透過率を測定し、平均値を求めた。
実施例1~5および比較例1~3で作製した各電磁波シールド部材の中赤外領域の透過率を測定した。
2500nm~18000nmの範囲で、Bluker社製FT-IR Vertex70を用いて透過率を測定し、2500nmから平均開口径の半分の長さの波長までの範囲での平均値を求めた。
結果を表2に示す。
これに対して、本発明の実施例はGHz帯のシールド特性を60dB以上とでき、かつ、紫外領域から可視光領域の透過率、近赤外領域の透過率および中赤外領域の透過性を確保することができることがわかる。
以上より本発明の効果は明らかである。
2 水酸化アルミニウム皮膜
3 貫通孔を有する金属箔
4 貫通孔を有する水酸化アルミニウム皮膜
5 貫通孔
10 電磁波シールド部材
12 金属箔
14 樹脂層
16 金属粒子
18 保護層
Claims (3)
- 厚み方向に貫通する貫通孔が複数形成された金属箔を備え、
前記貫通孔の平均開口径が1μm~100μm、平均開口率が1%~50%であり、
前記貫通孔の平均開口径が1μm以上、1.5μm未満において、
紫外領域から可視領域において、前記貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、前記平均開口率の10%以上であり、
前記貫通孔の平均開口径が1.5μm以上、5μm未満において、
紫外領域から可視領域の電磁波の透過率が、前記貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
近赤外領域において、前記貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、前記平均開口率の10%以上であり、
前記貫通孔の平均開口径が5μm以上において、
紫外領域から近赤外領域の電磁波の透過率が、前記貫通孔の平均開口率の絶対値-5%から+5%の範囲であり、
中赤外領域において、前記貫通孔の平均開口径の半分の長さの波長までの電磁波の透過率が、前記平均開口率の10%以上である電磁波シールド部材。 - 前記金属箔の厚みが5μm~1000μmである請求項1に記載の電磁波シールド部材。
- 前記金属箔が、アルミニウム箔、銅箔、銀箔、金箔、白金箔、ステンレス箔、チタン箔、タンタル箔、モリブデン箔、ニオブ箔、ジルコニウム箔、タングステン箔、ベリリウム銅箔、燐青銅箔、黄銅箔、洋白箔、錫箔、鉛箔、亜鉛箔、半田箔、鉄箔、ニッケル箔、パーマロイ箔、ニクロム箔、42アロイ箔、コバール箔、モネル箔、インコネル箔、および、ハステロイ箔からなる群から選択される箔であり、または、前記群から選択される箔と選択された箔とは異なる種類の金属とが積層されてなる箔である、請求項1または2に記載の電磁波シールド部材。
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EP18767722.4A EP3598863A4 (en) | 2017-03-13 | 2018-03-12 | ELECTROMAGNETIC SHAFT SHIELDING ELEMENT |
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JP2021068884A (ja) * | 2019-10-23 | 2021-04-30 | 東洋インキScホールディングス株式会社 | 電磁波シールドフィルムの製造方法 |
KR20210090090A (ko) * | 2020-01-09 | 2021-07-19 | 산시 우테 하이머 뉴 매테리얼스 테크놀러지 컴퍼니 리미티드 | 미세 다공성 포일의 제조 방법 |
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KR20200024915A (ko) * | 2017-08-23 | 2020-03-09 | 후지필름 가부시키가이샤 | 금속박, 금속박의 제조 방법, 이차 전지용 부극 및 이차 전지용 정극 |
CN111757660B (zh) * | 2020-07-15 | 2022-06-21 | 太原理工大学 | 一种非封闭式电磁屏蔽室 |
CN113056183B (zh) * | 2021-01-18 | 2022-10-28 | 哈尔滨工业大学 | 一种基于介质-超薄掺杂金属-介质的网栅结构电磁屏蔽光学窗 |
WO2022210210A1 (ja) * | 2021-03-29 | 2022-10-06 | 住友ベークライト株式会社 | 高周波拡散シート |
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JP2021068884A (ja) * | 2019-10-23 | 2021-04-30 | 東洋インキScホールディングス株式会社 | 電磁波シールドフィルムの製造方法 |
KR20210090090A (ko) * | 2020-01-09 | 2021-07-19 | 산시 우테 하이머 뉴 매테리얼스 테크놀러지 컴퍼니 리미티드 | 미세 다공성 포일의 제조 방법 |
KR102467926B1 (ko) | 2020-01-09 | 2022-11-15 | 산시 우테 하이머 뉴 매테리얼스 테크놀러지 컴퍼니 리미티드 | 미세 다공성 포일의 제조 방법 |
JPWO2021177138A1 (ja) * | 2020-03-02 | 2021-09-10 | ||
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JP7395711B2 (ja) | 2020-03-02 | 2023-12-11 | タツタ電線株式会社 | 金属層及び電磁波シールドフィルム |
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EP3598863A1 (en) | 2020-01-22 |
EP3598863A4 (en) | 2020-03-18 |
KR20190111115A (ko) | 2019-10-01 |
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