WO2017169672A1 - Radio wave absorbing adhesive sheet - Google Patents

Radio wave absorbing adhesive sheet Download PDF

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Publication number
WO2017169672A1
WO2017169672A1 PCT/JP2017/009842 JP2017009842W WO2017169672A1 WO 2017169672 A1 WO2017169672 A1 WO 2017169672A1 JP 2017009842 W JP2017009842 W JP 2017009842W WO 2017169672 A1 WO2017169672 A1 WO 2017169672A1
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WO
WIPO (PCT)
Prior art keywords
radio wave
matching layer
adhesive sheet
wave absorbing
sensitive adhesive
Prior art date
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PCT/JP2017/009842
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French (fr)
Japanese (ja)
Inventor
光次郎 鶴田
橋本　武司
服部　琢磨
Original Assignee
株式会社巴川製紙所
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Application filed by 株式会社巴川製紙所 filed Critical 株式会社巴川製紙所
Priority to JP2018508938A priority Critical patent/JPWO2017169672A1/en
Publication of WO2017169672A1 publication Critical patent/WO2017169672A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B9/00—Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • 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

Definitions

  • the present invention relates to a radio wave absorbing pressure-sensitive adhesive sheet that can impart radio wave absorbing performance by simply pasting it to a desired position afterwards.
  • the conventional electromagnetic wave absorbing material has a problem of low reflection attenuation.
  • this invention makes it a subject to provide the electromagnetic wave absorption material which has higher reflection attenuation property.
  • the present invention (1) is a radio wave absorption characterized in that two or more sets of laminated bodies in which a matching layer in which acicular conductive metal oxides are dispersed and fixed in a resin and an adhesive layer are laminated are laminated. It is an adhesive sheet for use.
  • the present invention (2) is the radio wave absorbing pressure-sensitive adhesive sheet according to the invention (1), wherein the laminate is laminated in two or three pairs.
  • the present invention (3) is the electromagnetic wave absorbing pressure-sensitive adhesive sheet according to the invention (1) or (2), wherein the needle-like conductive metal oxide has an aspect ratio of 5 or more.
  • the present invention (4) is the electromagnetic wave absorbing adhesive according to any one of the inventions (1) to (3), wherein the acicular conductive metal oxide is a conductive acicular titanium oxide. It is a sheet.
  • the present invention (5) is the radio wave absorbing pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer contains no metal or metal oxide.
  • the present invention it is possible to provide a radio wave absorbing material having higher reflection attenuation.
  • the radio wave absorbing material of the present invention is provided with an adhesive layer, it is possible to cope with a case where it is necessary to absorb a new radio frequency afterwards.
  • Radio wave absorbing adhesive sheet 1-1 Overall structure 1-2. Each part 1-2-1. Matching layer 1-2-1-1. Summary 1-2-1-2. Acicular conductive metal oxide 1-2-1-3. Resin 1-2-1-3-1. Component A 1-2-1-3-2. Component B 1-2-1-3-3. Other components 1-2-1-4. Formulation 1-2-1-4-1. Compounding amount of acicular conductive metal oxide 1-2-1-4-2. Needle-like conductive metal oxide / resin blend ratio 1-2-1-4-3. Ratio of component A / component B 1-2-2. Adhesive layer 1-2-3. 1. Releasable protective film 2. Production method of radio wave absorbing adhesive sheet How to use an electromagnetic wave absorbing adhesive sheet
  • Radio wave absorption adhesive sheet is a laminate of two or more laminates in which a matching layer in which acicular conductive metal oxides are dispersed and fixed in a resin and an adhesive layer are laminated. It is the adhesive sheet for electromagnetic wave absorption characterized by having performed.
  • the radio wave absorption adhesive sheet absorbs radio waves by laminating two or more layers of a matching layer and an adhesive layer having a different complex relative dielectric constant, thereby causing irregular reflection at the interface between the layers and attenuation for each layer. Is effective.
  • the number of laminates in the radio wave absorbing pressure-sensitive adhesive sheet is not particularly limited as long as it is 2 or more, but it is particularly preferable to laminate 2 or 3 pairs.
  • all of the stacked bodies that are stacked may be the same stacked body, or stacked bodies having different properties may be stacked.
  • another layer may exist between laminated bodies (namely, the electromagnetic wave absorption adhesive sheet which concerns on this invention is not restricted to the aspect which consists only of said 2 or more sets).
  • radio wave absorbing pressure-sensitive adhesive sheet protects the pressure-sensitive adhesive layer provided on the outermost layer until just before use, a peelable protective film can be bonded to the surface of the pressure-sensitive adhesive layer.
  • Matching layer The matching layer of the present invention is obtained by dispersing and fixing acicular conductive metal oxides to a resin layer.
  • the matching layer When the matching layer is attached to the radio wave reflector, the matching layer is reflected on the radio wave reflected by the interface between the radio wave reflector and the matching layer and on the surface of the matching layer. It is designed to control the amplitude and phase of radio waves so that they cancel each other.
  • the relationship between the real part and the imaginary part of the complex relative permittivity of the matching layer in the case where the radio wave is incident vertically and is non-reflecting is expressed as d / ⁇ (d: thickness of the matching layer, ⁇ : 1 is represented by a non-reflection condition curve shown in FIG.
  • the matching layer is designed so that the real part and the imaginary part of the complex relative permittivity are on the non-reflective curve by needle-like conductive metal oxide dispersed and fixed inside the matching layer.
  • the thickness of the matching layer is determined according to the wavelength (or frequency) of the matching layer.
  • the wavelength (or frequency) of the absorbed radio wave is determined by the total thickness of all the matching layers. Therefore, the thickness of each matching layer of each stacked body included in the matching layer is a value obtained by dividing the total thickness of all the matching layers by the number of stacked layers.
  • each matching layer contained in the laminate to be laminated is not particularly limited, but if it is too thick, the characteristics as a sheet are lost, and if it is too thin, the acicular conductive metal oxide is dispersed. Making it difficult to manufacture.
  • the conductive metal oxide dispersed and fixed in the matching layer is preferably random without being oriented, and more preferably randomly dispersed three-dimensionally.
  • the radio wave absorbing pressure-sensitive adhesive sheet has anisotropy, radio wave absorption also exhibits anisotropy, and the absorption performance may vary depending on the radio wave direction.
  • Needle-like conductive metal oxide (referred to as Component C) is not particularly limited as long as it is a needle-like conductive metal oxide.
  • conductive coated ferrite or oxide examples thereof include titanium, ITO, antimony-doped tin oxide, and cobalt oxide.
  • conductive refers to a material having a low volumetric efficiency of 10 8 ⁇ ⁇ cm or less.
  • conductive acicular titanium oxide in that the dielectric constant is high and the real part of the complex relative dielectric constant is easy to design.
  • acicular titanium oxide the process of growing a titanium dioxide nucleus crystal by heating and firing a titanium compound, an alkali metal compound, and an oxyphosphorus compound in the presence of a titanium dioxide nucleus crystal having an axial ratio of 2 or more is repeated. Is obtained. Then, the conductive acicular titanium oxide is precipitated by adding a solution containing a tin compound and a solution containing a compound such as antimony or phosphorus to the suspension in which the obtained acicular titanium oxide is suspended. The obtained product is obtained by heating and baking.
  • the average diameter of the acicular conductive metal oxide is preferably 0.05 to 5.0 ⁇ m, the average length is preferably 0.5 to 50 ⁇ m, and the average diameter is 0.15. More preferably, the average length is 2 to 20 ⁇ m.
  • the conductive metal oxide preferably has an aspect ratio of 5 or more, and the upper limit is not limited. However, if the aspect ratio is too large, the conductive metal oxide is oriented in the matching layer. May end up. In addition, when the aspect ratio is small, the radio wave absorption efficiency is significantly reduced. Therefore, the aspect ratio is preferably 2 to 100, more preferably 3 to 50, and further preferably 5 to 30.
  • the values of “average diameter”, “average length”, and “aspect ratio” are values obtained by observing and measuring at least 100 particles of the conductive metal oxide and measuring the average value. is there. More specifically, the “average diameter” is the same as the cross-sectional area calculated by calculating the cross-sectional area of the particle based on the vertical cross section near the center in the length direction of the particle imaged by SEM observation (for example, with known software) It is the average value of the area diameters derived by calculating the diameter of a circle having an area. The average diameter and average length are values obtained from the ratio of the average diameter to the average length for the measurement average and aspect ratio of 100 particles.
  • the conductive metal oxide may be subjected to a surface treatment using an inorganic compound, an organic compound, or a combination of an inorganic compound and an organic compound.
  • an inorganic compound and an organic compound are used in combination, if the organic compound is coated on the outermost part, the dispersion in the resin composition tends to be facilitated, and the familiarity with the polymerizable resin component and / or the polymerization initiator component is increased. Since it becomes favorable, it is preferable.
  • inorganic compounds include silicon, zirconium, aluminum, titanium oxides, and hydrated oxides. These may be used alone, or two or more of them may be laminated or mixed together. You can also.
  • organic compound examples include organosilicon compounds, organometallic compounds, polyols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, higher hydrocarbons or derivatives thereof, and the like.
  • the organic compound can be used alone or in combination by laminating or mixing two or more kinds.
  • organosilicon compounds include straight polysiloxane (dimethylpolysiloxane, methylhydrogen polysiloxane, methylmethoxypolysiloxane, methylphenylpolysiloxane, etc.), modified polysiloxane (dimethylpolysiloxanediol, dimethylpolysiloxane dihydrogen, side Side chain or both ends amino-modified polysiloxane, side chain or both ends or one end epoxy-modified polysiloxane, both ends or one end methacryl-modified polysiloxane, side chain or both ends carboxyl modified polysiloxane, side chain or both ends or one end Carbinol-modified polysiloxane, both-end phenol-modified polysiloxane, side-chain or both-end mercapto-modified polysiloxane, both-end or side-chain polyether-modified polysiloxane, side-chain alky
  • organometallic compounds include aminoalkoxytitanium (isopropyltri (N-aminoethyl-aminoethyl) titanate, etc.), phosphoric acid ester titanium (isopropyltris (dioctylpyrophosphate) titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (Dioctyl pyrophosphate) ethylene titanate), carboxylic acid ester titanium (isopropyl triisostearoyl titanate, etc.), sulfonic acid ester titanium (isopropyl-n-dodecylbenzenesulfonyl titanate, etc.), titanium chelate (titanium diisopropoxybisacetylacetonate) , Titanium diisopropoxybisethyl acetoacetate, octylene glycol titanate, etc.)), phosphorous Ester titanium complexes (te
  • polyols examples include trimethylolpropane, trimethylolethane, pentaerythritol and the like.
  • alkanolamines examples include monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, and tripropanolamine.
  • Derivatives thereof include acetates, oxalates, tartrate, and formic acid.
  • Examples thereof include organic acid salts such as salts and benzoates.
  • higher fatty acids include stearic acid, lauric acid, oleic acid and the like
  • metal salts thereof include aluminum salts, zinc salts, magnesium salts, calcium salts, barium salts and the like.
  • Examples of higher hydrocarbons include paraffin wax and polyethylene wax, and examples of derivatives thereof include perfluorinated products thereof.
  • the method for coating the surface of particles of a needle-like conductive metal oxide (for example, titanium oxide) with an inorganic compound or an organic compound can be carried out by any known method, whether dry or wet.
  • Resin The resin which is the base material of the matching layer is typically obtained by energy curing a resin composition containing a polymerizable resin (referred to as component A) and a polymerization initiator (referred to as component B). .
  • component A a polymerizable resin
  • component B a polymerization initiator
  • Component A is not particularly limited, and can be selected from ester-based polymer resins, urethane-based polymer resins, epoxy-based polymer resins, acrylic resins, and the like. Considering that the radio wave absorbing pressure-sensitive adhesive sheet according to the present invention is used outdoors, an acrylic polymer resin having high weather resistance is preferable.
  • the acrylic polymerizable resin it is preferable to use an epoxy acrylate having a vinyl group, a urethane acrylate, an ester acrylate, a copolymer acrylate, a butadiene acrylate, a silicon acrylate, and / or an amino resin acrylate, and more preferably a repeating unit.
  • Epoxy acrylate, urethane acrylate, polyester acrylate, copolymer acrylate, butadiene acrylate, silicon acrylate, amino resin acrylate, etc. which are acrylic oligomers of about 2 to 20 and have 2 to 6 vinyl groups at the ends. Among them, trifunctional or lower functional group is preferable in that it is easy to suppress curing shrinkage of the resin.
  • urethane acrylate having a weight average molecular weight of 500 to 10,000 and a viscosity of 3,000 to 500,000 mPa ⁇ s / 25 ° C. is a solvent-free system.
  • the viscosity is more preferably 5,000 to 200,000 mPa ⁇ s / 25 ° C., and most preferably 6,000 or more.
  • the viscosity is 3,000 mPa ⁇ s / 25 ° C. or more, the acicular conductive oxide is likely to be randomly dispersed three-dimensionally in the matching layer, so that the reflection attenuation can be easily improved.
  • the matching layer can be formed without a solvent, it is easy to suppress the dimensional change of the matching layer due to volatilization of the residual solvent.
  • the weight average molecular weight is a value measured using gel permeation chromatography (manufactured by JASCO Corporation) in accordance with JIS K7252, and the viscosity is a value measured using an E-type viscometer. is there.
  • Component B is not particularly limited and can be selected from those suitable for the polymerization reaction of selected component A.
  • the case where the component A is an acrylic resin will be described below.
  • an organic peroxide When combined with an acrylic polymerizable resin, an organic peroxide is preferred.
  • the organic peroxide is suitable in that the temperature at which the acrylic resin composition is polymerized and cured without a solvent can be freely set in a temperature range from room temperature to about 300 ° C.
  • organic peroxide examples include methyl ethyl ketone peroxide, cyclohexane peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (t- Butylperoxy) -3,3,5 trimethylhexane, 1,1-bis (t-butylperoxy) -cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,4- Bis (t-butylperoxy) valate, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, di-isopropylbenzene hydroperoxide, p-menthane hydroperoxide I 2,5-dimethylhexane-2,5-dihydroperoxide, 1,
  • filler components other than the conductive metal oxide can be added.
  • the filler component may be organic or inorganic, but when it is an organic filler, it is preferably insoluble in the resin components A and B.
  • the inorganic filler whose real part of a complex dielectric constant is 4 or less is suitable, and an aluminum hydroxide, silicon dioxide, etc. are mentioned as an example.
  • the addition amount of these filler components can be arbitrarily set depending on the electromagnetic waves to be absorbed, the addition amount of the acicular conductive metal oxide corresponding thereto, etc. The amount is 200 parts by mass, preferably 18 to 100 parts by mass.
  • 1-2-1-4 Formulation 1-2-1-4-1.
  • the amount of acicular conductive metal oxide blended The content of (component C) in the matching layer for obtaining the most ideal electromagnetic wave absorption performance is determined by the frequency of the electromagnetic wave for absorption and the complex relative dielectric corresponding thereto It can be arbitrarily determined by the rate. That is, the addition amount should be such that it falls on the non-reflection condition curve.
  • the mixing ratio of acicular conductive metal oxide / resin is arbitrarily determined by the frequency of electromagnetic waves for absorption and the complex relative dielectric constant corresponding thereto. However, in forming the layer, the amount is preferably less than 300 parts by mass with respect to the resin component.
  • Ratio of Component A / Component B Regarding the blending of Component A and Component B, the mass ratio represented by (Component A / Component B) is preferably 10 to 2,000, preferably 20 to 1,000. More preferably, it is more preferably 33 to 200.
  • the mass ratio exceeds 2,000, the curing reaction becomes insufficient, the weight of the residual uncured component decreases when left in a high temperature state for a long time, and the matching layer shrinks. There is a risk of deviation from a desired frequency band.
  • it is less than 10 the curing shrinkage of the matching layer becomes large, and it may be difficult to adjust the thickness of the layer when producing the electromagnetic wave absorber.
  • Adhesive layer It is preferred that the adhesive layer contains no metal or metal oxide or contains only about trace amounts. This is because the radio wave absorption efficiency increases as the difference in complex relative permittivity between the matching layer and the adhesive layer increases. However, even if the adhesive layer contains metal, radio wave absorption is possible if the difference in complex relative permittivity between the matching layer and the adhesive layer is large.
  • the pressure-sensitive adhesive layer can be selected from any adhesive composition or pressure-sensitive adhesive composition. Specifically, acrylic adhesive, silicone adhesive, urethane adhesive, polyvinyl butyral adhesive (PVB), ethylene-vinyl acetate adhesive (EVA), etc., polyvinyl ether, saturated amorphous polyester, melamine resin Etc.
  • the thickness of the adhesive layer is not particularly limited as long as the structure as a radio wave absorbing adhesive sheet can be maintained, but is generally 5 to 100 ⁇ m, preferably 5 to 50 ⁇ m, more preferably 10 to 25 ⁇ m. If it is less than 5 ⁇ m, there is a possibility that sufficient adhesive strength cannot be secured, and if it exceeds 100 ⁇ m, it is not preferable in that the thickness of the entire sheet increases.
  • peelable protective film The material of the peelable protective film used in the present invention is not particularly limited, but a polypropylene film, a fluororesin-based film, a polyethylene film, a polyethylene terephthalate (PET) film, paper, and a silicone resin are subjected to a peeling treatment. What gave (exfoliation processing film) etc. are mentioned.
  • the thickness of the peelable protective film is not particularly limited, but is preferably 1 to 200 ⁇ m, and more preferably 10 to 50 ⁇ m.
  • the peelable protective film preferably has a peel strength of 1.0 to 50 g / cm.
  • it is 1.0 g / cm or less, the adhesive layer and the peelable protective film are easily peeled off during the curing of the adhesive layer in the production process of the adhesive layer, and the surface of the adhesive layer is likely to be uneven.
  • it is 50 g / cm or more, there is a possibility that defects or the like may occur when the adhesive layer and the peelable protective film are peeled off.
  • the pressure-sensitive adhesive sheet for radio wave absorption of the present invention can be manufactured using various known methods. For example, a coating for forming a matching layer (coating mixed with raw materials for a matching layer) applied to a PET film or the like, and a coating for forming an adhesive layer (raw material for an adhesive layer) applied to another PET film or the like Are bonded together, and a set of laminated bodies in which the matching layer and the adhesive layer are laminated can be formed.
  • the electromagnetic wave absorbing pressure-sensitive adhesive sheet is obtained by laminating a plurality of the obtained laminates.
  • the radio wave absorbing adhesive sheet is used by being attached to an object that is a radio wave reflector via an outermost adhesive layer.
  • the object which is a radio wave reflector and the adhesive sheet for radio wave absorption of the present application are combined to function as a matching type radio wave absorber.
  • the outermost adhesive layer can be changed in accordance with the object to be attached.
  • ⁇ Matching layer creation method Polymerizable resin component: Polyurethane acrylate having a weight average molecular weight of 2,500 and a viscosity of 6,500 mPa ⁇ s / 25 ° C. (trade name: “Beam Set 505A-6”, manufactured by Arakawa Chemical Industries Ltd.), 100 parts by mass, polymerization initiator component : 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate (trade name: “Perocta O” manufactured by NOF Corporation), 1.0 wt.
  • the matching layer forming coating material (coating material mixed with the matching layer raw material) was prepared by stirring by the above method.
  • the resulting paint was applied onto a PET film to form a matching layer. Furthermore, the PET film was bonded to the exposed surface of the matching layer, heated in a hot-air circulating drier at 100 ° C. for 10 minutes to cure the matching layer, and the PET film was peeled to obtain a matching layer.
  • the prepared pressure-sensitive adhesive is applied to a peelable PET film (product name: PET38C, manufactured by Lintec Co., Ltd.) with an applicator so that the thickness of the pressure-sensitive adhesive layer after drying becomes a desired thickness. And dried for 2 minutes to form an adhesive layer.
  • a peelable PET film product name: PET38C, manufactured by Lintec Co., Ltd.
  • Example 1 As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m A matching layer having a thickness of 350 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 1 laminated in two sets.
  • Example 2 As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m A matching layer having a thickness of 225 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Three sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface repeatedly to obtain a radio wave absorbing pressure-sensitive adhesive sheet of Example 2 laminated in three sets.
  • Example 3 As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m A matching layer having a thickness of 162 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface, and four sets of laminated radio wave absorbing adhesive sheets of Example 3 were obtained.
  • Example 4 11.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 654 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorption adhesive sheet of Example 4 in which two sets were laminated.
  • Example 5 23.8 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 205 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorption adhesive sheet of Example 5 in which two sets were laminated.
  • Example 6 30.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 144 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 6 in which two sets were laminated.
  • Example 7 31.0 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m is used as the conductive metal oxide used for the matching layer preparation.
  • a matching layer having a thickness of 138 ⁇ m was formed.
  • the adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 7 in which two sets were laminated.
  • Example 8 As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) As other components, 58.0 parts by mass of amorphous aluminum hydroxide having an average diameter of 1 ⁇ m (trade name: “BF013” manufactured by Nippon Light Metal Co., Ltd.) was used to form a matching layer having a thickness of 350 ⁇ m. The adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 8 in which two sets were laminated.
  • Comparative Example 1 As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m A matching layer having a thickness of 700 ⁇ m was formed. The adhesive layer was prepared to have a thickness of 25 ⁇ m. In this way, the matching layer and the adhesive layer formed on the peelable PET film were bonded together to obtain the radio wave absorbing adhesive sheet of Comparative Example 1.
  • conductive acicular titanium oxide trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.
  • Comparative Example 2 instead of the conductive metal oxide used to make the matching layer, it was changed to non-conductive acicular titanium oxide (trade name: “FTL-400” manufactured by Ishihara Sangyo Co., Ltd.) with an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m. Except for the above, a radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 2 was obtained in the same manner as Example 1.
  • FTL-400 non-conductive acicular titanium oxide manufactured by Ishihara Sangyo Co., Ltd.
  • Comparative Example 3 The same procedure as in Example 1 was conducted except that the conductive metal oxide used for preparing the matching layer was changed to conductive spherical titanium oxide (trade name: “ET-500W” manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 0.25 ⁇ m. Thus, an electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 3 was obtained.
  • Comparative Example 4 Example except that non-conductive amorphous barium titanate with an average particle size of 0.5 ⁇ m (trade name: “HPBT-1” manufactured by Fuji Titanium Co., Ltd.) was used instead of the conductive metal oxide used for the matching layer preparation. In the same manner as in Example 1, a radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 4 was obtained.
  • Comparative Example 5 11.0 mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m instead of the conductive metal oxide used for the matching layer preparation
  • the electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 5 was obtained in the same manner as Comparative Example 1, except that the thickness was changed to 1334 ⁇ m.
  • Comparative Example 6 conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) 23.8 mass
  • the electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 6 was obtained in the same manner as in Comparative Example 1 except that the thickness was changed to 434 ⁇ m.
  • Comparative Example 7 30.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 7 was obtained in the same manner as Comparative Example 1 except that the thickness was changed to 316 ⁇ m.
  • Comparative Example 8 31.0 mass of conductive acicular titanium oxide (trade name: “FT-4000”, manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 ⁇ m and an average length of 10.0 ⁇ m instead of the conductive metal oxide used for producing the matching layer
  • the electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 8 was obtained in the same manner as in Comparative Example 1, except that the thickness was changed to 299 ⁇ m.
  • test pieces having a length of 150 mm and a width of 150 mm were prepared and pasted on an aluminum plate having a thickness of 50 ⁇ m, respectively.
  • As an absorber the return attenuation of radio waves in the 20 to 110 GHz frequency band was measured.
  • “free space type S parameter measuring device” manufactured by Kanto Electronics Application Development Co., Ltd. was used, and measurement was performed by “PNA network analyzer N5225A” manufactured by Keysight Technology.
  • the reflection attenuation is the reflection attenuation at the maximum wave absorption wavelength. Table 1 shows the measured values of reflection attenuation at each peak absorption wavelength for the examples and comparative examples.
  • FIG. 3 is a return attenuation curve measured in Example 1. It can be understood that the peak of the obtained reflection attenuation curve is sharp and the frequency selectivity is high.
  • Comparative Examples 1 and 5 to 8 in which the matching layer is not laminated have low reflection attenuation and low radio wave absorption. It can be understood that, when the number of stacked layers is two or more, the radio wave absorption becomes high, but when the number of stacked layers exceeds three sets, the radio wave absorption starts to decrease.
  • the radio wave absorption pressure-sensitive adhesive sheet of the present invention is a matching layer of a matching type radio wave absorber having high frequency selectivity and excellent radio wave absorption.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Laminated Bodies (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
  • Adhesive Tapes (AREA)

Abstract

[Problem] To provide a radio wave absorbing material having increased reflective attenuation. [Solution] A radio wave absorbing adhesive sheet is characterized in that two or more sets of laminates are stacked, the laminates comprising a stack of a matching layer having needle-like conductive metal oxides dispersed and fixed in a resin, and an adhesive layer.

Description

電波吸収用粘着シートRadio wave absorbing adhesive sheet
　本発明は、事後的に所望の位置に貼り付けるだけで電波吸収性能を付与することのできる電波吸収用粘着シートに関するものである。 The present invention relates to a radio wave absorbing pressure-sensitive adhesive sheet that can impart radio wave absorbing performance by simply pasting it to a desired position afterwards.
　近年、電波の利用用途が多様に広がりを見せるなか、その電波障害が大きな問題となっている。当該問題を解決すべく、例えば、フェライト、またはフェライトと金属粉末もしくはカーボン粉末との混合物を有機高分子中に分散させた電波吸収材料が提案されている（例えば特許文献１）。 In recent years, radio wave interference has become a major problem as the use of radio waves has expanded in various ways. In order to solve the problem, for example, a radio wave absorbing material in which ferrite or a mixture of ferrite and metal powder or carbon powder is dispersed in an organic polymer has been proposed (for example, Patent Document 1).
特開平４－２１１１９９号公報Japanese Patent Laid-Open No. 4-211199
　しかしながら、従来型の前記電波吸収材料は反射減衰性が低いという課題がある。そこで、本発明は、より高い反射減衰性を有する電波吸収材料を提供することを課題とする。 However, the conventional electromagnetic wave absorbing material has a problem of low reflection attenuation. Then, this invention makes it a subject to provide the electromagnetic wave absorption material which has higher reflection attenuation property.
　本発明（１）は、針状の導電性金属酸化物が樹脂中に分散固定された整合層と、粘着層と、を積層した積層体を、２組以上積層したことを特徴とする電波吸収用粘着シートである。
　本発明（２）は、前記積層体が２組または３組積層されたことを特徴とする発明（１）に記載の電波吸収用粘着シートである。
　本発明（３）は、前記針状の導電性金属酸化物のアスペクト比が５以上であることを特徴とする発明（１）または（２）に記載の電波吸収用粘着シートである。
　本発明（４）は、前記針状の導電性金属酸化物が導電性針状酸化チタンであることを特徴とする発明（１）乃至（３）のいずれか一項に記載の電波吸収用粘着シートである。
　本発明（５）は、前記粘着層には金属および金属酸化物が含まれないことを特徴とする請求項１乃至４のいずれか一項に記載の電波吸収用粘着シートである。 The present invention (1) is a radio wave absorption characterized in that two or more sets of laminated bodies in which a matching layer in which acicular conductive metal oxides are dispersed and fixed in a resin and an adhesive layer are laminated are laminated. It is an adhesive sheet for use.
The present invention (2) is the radio wave absorbing pressure-sensitive adhesive sheet according to the invention (1), wherein the laminate is laminated in two or three pairs.
The present invention (3) is the electromagnetic wave absorbing pressure-sensitive adhesive sheet according to the invention (1) or (2), wherein the needle-like conductive metal oxide has an aspect ratio of 5 or more.
The present invention (4) is the electromagnetic wave absorbing adhesive according to any one of the inventions (1) to (3), wherein the acicular conductive metal oxide is a conductive acicular titanium oxide. It is a sheet.
The present invention (5) is the radio wave absorbing pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer contains no metal or metal oxide.
　本発明によれば、より高い反射減衰性を有する電波吸収材料を提供することが可能となる。加えて、本発明の電波吸収材料は粘着層を備えているために、事後的に新たな電波周波数を吸収することが必要になった場合にも対応可能である。 According to the present invention, it is possible to provide a radio wave absorbing material having higher reflection attenuation. In addition, since the radio wave absorbing material of the present invention is provided with an adhesive layer, it is possible to cope with a case where it is necessary to absorb a new radio frequency afterwards.
無反射条件曲線を示すグラフである。It is a graph which shows a non-reflective condition curve. 本発明の電波吸収用粘着シートの実施の態様例の断面図である。It is sectional drawing of the example of an embodiment of the adhesive sheet for electromagnetic wave absorption of this invention. 実施例１の電波吸収用粘着シートの反射減衰性曲線である。2 is a reflection attenuation curve of the radio wave absorbing pressure-sensitive adhesive sheet of Example 1.
　以下、本発明を下記の順で説明する。
１．電波吸収用粘着シート
１－１．全体構造
１－２．各部
１－２－１．整合層
１－２－１－１．概括
１－２－１－２．針状の導電性金属酸化物
１－２－１－３．樹脂
１－２－１－３－１．成分Ａ
１－２－１－３－２．成分Ｂ
１－２－１－３－３．その他の成分
１－２－１－４．配合
１－２－１－４－１．針状の導電性金属酸化物の配合量
１－２－１－４－２．針状の導電性金属酸化物／樹脂の配合比
１－２－１－４－３．成分Ａ／成分Ｂの比率
１－２－２．粘着層
１－２－３．剥離性保護フィルム
２．電波吸収用粘着シートの製造方法
３．電波吸収用粘着シートの使用方法 Hereinafter, the present invention will be described in the following order.
1. 1. Radio wave absorbing adhesive sheet 1-1. Overall structure 1-2. Each part 1-2-1. Matching layer 1-2-1-1. Summary 1-2-1-2. Acicular conductive metal oxide 1-2-1-3. Resin 1-2-1-3-1. Component A
1-2-1-3-2. Component B
1-2-1-3-3. Other components 1-2-1-4. Formulation 1-2-1-4-1. Compounding amount of acicular conductive metal oxide 1-2-1-4-2. Needle-like conductive metal oxide / resin blend ratio 1-2-1-4-3. Ratio of component A / component B 1-2-2. Adhesive layer 1-2-3. 1. Releasable protective film 2. Production method of radio wave absorbing adhesive sheet How to use an electromagnetic wave absorbing adhesive sheet
１．電波吸収用粘着シート
　本発明による電波吸収用粘着シートは、針状の導電性金属酸化物が樹脂中に分散固定された整合層と、粘着層とを、積層した積層体を、２組以上積層したことを特徴とする電波吸収用粘着シートである。 1. Radio wave absorption adhesive sheet The radio wave absorption adhesive sheet according to the present invention is a laminate of two or more laminates in which a matching layer in which acicular conductive metal oxides are dispersed and fixed in a resin and an adhesive layer are laminated. It is the adhesive sheet for electromagnetic wave absorption characterized by having performed.
１－１．全体構造
　前記電波吸収用粘着シートは、整合層と複素比誘電率の異なる粘着層との、積層体を２組以上積層することで、層界面での乱反射や層ごとの減衰により、電波の吸収を効果的にしたものである。前記電波吸収用粘着シートにおける積層体の積層数は、２組以上である限りは特に限定されないが、２組または３組を積層させることが特に好ましい。 1-1. Overall structure The radio wave absorption adhesive sheet absorbs radio waves by laminating two or more layers of a matching layer and an adhesive layer having a different complex relative dielectric constant, thereby causing irregular reflection at the interface between the layers and attenuation for each layer. Is effective. The number of laminates in the radio wave absorbing pressure-sensitive adhesive sheet is not particularly limited as long as it is 2 or more, but it is particularly preferable to laminate 2 or 3 pairs.
　ここで、複数積層される前記積層体は、全てが同一の積層体を積層してもよいし、各性質の異なる積層体を積層してもよい。なお積層体の間に、別の層が存在してもよい（即ち、本発明に係る電波吸収用粘着シートは、前記２以上の組のみからなる態様には限られない）。 Here, all of the stacked bodies that are stacked may be the same stacked body, or stacked bodies having different properties may be stacked. In addition, another layer may exist between laminated bodies (namely, the electromagnetic wave absorption adhesive sheet which concerns on this invention is not restricted to the aspect which consists only of said 2 or more sets).
　前記電波吸収用粘着シートは、最外層に設けられた粘着層を使用直前まで保護するため、前記粘着層表面に剥離性保護フィルムを貼り合わせることができる。 Since the radio wave absorbing pressure-sensitive adhesive sheet protects the pressure-sensitive adhesive layer provided on the outermost layer until just before use, a peelable protective film can be bonded to the surface of the pressure-sensitive adhesive layer.
１－２．各部
１－２－１．整合層
　本発明の整合層は、樹脂層に針状の導電性金属酸化物を分散固定したものである。 1-2. Each part 1-2-1. Matching layer The matching layer of the present invention is obtained by dispersing and fixing acicular conductive metal oxides to a resin layer.
１－２－１－１．概括
　前記整合層は、前記整合層が電波反射体に貼り付けられた際に、前記電波反射体と、前記整合層との、界面で反射された電波と、前記整合層の表面で反射された電波とが、打ち消しあうように、それら電波の振幅と位相を制御するように設計される。電波が、垂直に入射する場合において、無反射となる場合の前記整合層の複素比誘電率の、実部と、虚部の関係は、ｄ／λ（ｄ：整合層の厚さ、λ：電波の波長）に応じて変化し、図１に示す無反射条件曲線で表される。前記整合層は、その内部に分散固定される針状の導電性金属酸化物によって、複素比誘電率の実部と、虚部が、前記無反射曲線上になるように設計され、吸収したい電波の波長（または周波数）に応じて、前記整合層の厚さが決められる。 1-2-1-1. General When the matching layer is attached to the radio wave reflector, the matching layer is reflected on the radio wave reflected by the interface between the radio wave reflector and the matching layer and on the surface of the matching layer. It is designed to control the amplitude and phase of radio waves so that they cancel each other. The relationship between the real part and the imaginary part of the complex relative permittivity of the matching layer in the case where the radio wave is incident vertically and is non-reflecting is expressed as d / λ (d: thickness of the matching layer, λ: 1 is represented by a non-reflection condition curve shown in FIG. The matching layer is designed so that the real part and the imaginary part of the complex relative permittivity are on the non-reflective curve by needle-like conductive metal oxide dispersed and fixed inside the matching layer. The thickness of the matching layer is determined according to the wavelength (or frequency) of the matching layer.
　本発明のように整合層が積層されている場合には、全ての整合層の厚さの合計によって、吸収される電波の波長（または周波数）が決まる。したがって、前記整合層に含まれる各積層体の各整合層の厚さは、前記すべての整合層の厚さの合計を、積層数で除した値となる。 When the matching layers are laminated as in the present invention, the wavelength (or frequency) of the absorbed radio wave is determined by the total thickness of all the matching layers. Therefore, the thickness of each matching layer of each stacked body included in the matching layer is a value obtained by dividing the total thickness of all the matching layers by the number of stacked layers.
　積層される前記積層体に、含まれる各整合層の厚さは、特に限定されないが、厚くなりすぎるとシートとしての特性が失われ、薄すぎると、前記針状の導電性金属酸化物を分散させることが困難となり、製造が困難となる。 The thickness of each matching layer contained in the laminate to be laminated is not particularly limited, but if it is too thick, the characteristics as a sheet are lost, and if it is too thin, the acicular conductive metal oxide is dispersed. Making it difficult to manufacture.
　前記整合層内に、分散固定される前記導電性金属酸化物は、配向せずにランダムになっていることが好ましく、３次元的にランダム分散していることがより好ましい。前記導電性金属酸化物が配向すると、前記電波吸収用粘着シートが異方性を有してしまい、電波吸収も異方性を示し、電波方向によって吸収性能がばらつきを持つおそれがある。 The conductive metal oxide dispersed and fixed in the matching layer is preferably random without being oriented, and more preferably randomly dispersed three-dimensionally. When the conductive metal oxide is oriented, the radio wave absorbing pressure-sensitive adhesive sheet has anisotropy, radio wave absorption also exhibits anisotropy, and the absorption performance may vary depending on the radio wave direction.
１－２－１－２．針状の導電性金属酸化物
　針状の導電性金属酸化物（成分Ｃとする）は、針状の導電性金属酸化物である限り特に限定されず、例えば、導電性コートされたフェライトや酸化チタン、ＩＴＯ、アンチモンドープ酸化スズ、コバルト酸化物などが挙げられる。ここで、「導電性」とは、体積低効率が１０８Ω・ｃｍ以下の抵抗を有するものをいう。 1-2-1-2. Needle-like conductive metal oxide Needle-like conductive metal oxide (referred to as Component C) is not particularly limited as long as it is a needle-like conductive metal oxide. For example, conductive coated ferrite or oxide Examples thereof include titanium, ITO, antimony-doped tin oxide, and cobalt oxide. Here, “conductive” refers to a material having a low volumetric efficiency of 10 8 Ω · cm or less.
　これらは、単独または２種類以上組み合わせて用いることが可能である。中でも誘電率が高く、複素比誘電率の実部を設計しやすい点で、導電性針状酸化チタンを含むことが好ましい。針状酸化チタンは、２以上の軸比を有する二酸化チタン核晶の存在下、チタン化合物、アルカリ金属化合物及びオキシリン化合物を加熱焼成して二酸化チタン核晶を成長させる工程を２回以上繰り返すこと等により得られる。そして、導電性針状酸化チタンは、得られた針状酸化チタンを懸濁した懸濁液に、スズ化合物を含む溶液とアンチモン、リン等の化合物を含む溶液を加えて、沈殿させ、次いで、得られた生成物を加熱焼成すること等により得られる。 These can be used alone or in combination of two or more. Among them, it is preferable to include conductive acicular titanium oxide in that the dielectric constant is high and the real part of the complex relative dielectric constant is easy to design. In acicular titanium oxide, the process of growing a titanium dioxide nucleus crystal by heating and firing a titanium compound, an alkali metal compound, and an oxyphosphorus compound in the presence of a titanium dioxide nucleus crystal having an axial ratio of 2 or more is repeated. Is obtained. Then, the conductive acicular titanium oxide is precipitated by adding a solution containing a tin compound and a solution containing a compound such as antimony or phosphorus to the suspension in which the obtained acicular titanium oxide is suspended. The obtained product is obtained by heating and baking.
　針状の導電性金属酸化物（例えば導電性針状酸化チタン）の平均径は、０．０５～５．０μｍ、平均長は、０．５～５０μｍであることが好ましく、平均径０．１５～１．０μｍ、平均長２～２０μｍであることが更に好ましい。また、前記導電性金属酸化物は、アスペクト比が５以上であることが好ましく、上限は限定されないが、アスペクト比が大きすぎると、前記整合層中において、前記導電性金属酸化物が配向してしまう場合がある。また、アスペクト比が小さい場合には、電波吸収効率が著しく低下する。そのためアスペクト比は２～１００が好適であり、３～５０がより好適であり、５～３０がさらに好適である。ここで、「平均径」、「平均長」、「アスペクト比」の値は、前記導電性金属酸化物をＳＥＭ観察し、少なくとも１００個の粒子を観察測定し、その平均値から求めた値である。より詳細には「平均径」とは、ＳＥＭ観察で撮像された粒子の長さ方向中心付近における垂直断面に基づき粒子の断面積を算出し（例えば、公知ソフトにて）、当該断面積と同一面積を有する円の直径を算出することにより導かれた面積径の平均値である。平均径と平均長は１００粒子の測定平均、アスペクト比については、平均径と平均長の比から求めた値である。 The average diameter of the acicular conductive metal oxide (for example, conductive acicular titanium oxide) is preferably 0.05 to 5.0 μm, the average length is preferably 0.5 to 50 μm, and the average diameter is 0.15. More preferably, the average length is 2 to 20 μm. The conductive metal oxide preferably has an aspect ratio of 5 or more, and the upper limit is not limited. However, if the aspect ratio is too large, the conductive metal oxide is oriented in the matching layer. May end up. In addition, when the aspect ratio is small, the radio wave absorption efficiency is significantly reduced. Therefore, the aspect ratio is preferably 2 to 100, more preferably 3 to 50, and further preferably 5 to 30. Here, the values of “average diameter”, “average length”, and “aspect ratio” are values obtained by observing and measuring at least 100 particles of the conductive metal oxide and measuring the average value. is there. More specifically, the “average diameter” is the same as the cross-sectional area calculated by calculating the cross-sectional area of the particle based on the vertical cross section near the center in the length direction of the particle imaged by SEM observation (for example, with known software) It is the average value of the area diameters derived by calculating the diameter of a circle having an area. The average diameter and average length are values obtained from the ratio of the average diameter to the average length for the measurement average and aspect ratio of 100 particles.
　また、前記導電性金属酸化物は、無機化合物や有機化合物、あるいは無機化合物と有機化合物を組み合わせて、表面処理を行ってもよい。無機化合物と有機化合物を併用する場合、有機化合物を最外部に被覆すると、樹脂組成物中への分散が容易になる傾向があると共に、重合性樹脂成分および／又は重合開始剤成分との馴染みが良好となるため好ましい。無機化合物としては、例えば、ケイ素、ジルコニウム、アルミニウム、チタニウムの酸化物、水和酸化物が挙げられ、これらを単独で用いてもよく、２種以上を積層させたり、混合させたりして併用することもできる。有機化合物としては、例えば、有機ケイ素化合物、有機金属化合物、ポリオール類、アルカノールアミン類又はその誘導体、高級脂肪酸類又はその金属塩、高級炭化水素類又はその誘導体等が挙げられる。有機化合物も単独でも、２種以上を積層又は混合するなどして併用することができる。 Further, the conductive metal oxide may be subjected to a surface treatment using an inorganic compound, an organic compound, or a combination of an inorganic compound and an organic compound. When an inorganic compound and an organic compound are used in combination, if the organic compound is coated on the outermost part, the dispersion in the resin composition tends to be facilitated, and the familiarity with the polymerizable resin component and / or the polymerization initiator component is increased. Since it becomes favorable, it is preferable. Examples of inorganic compounds include silicon, zirconium, aluminum, titanium oxides, and hydrated oxides. These may be used alone, or two or more of them may be laminated or mixed together. You can also. Examples of the organic compound include organosilicon compounds, organometallic compounds, polyols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, higher hydrocarbons or derivatives thereof, and the like. The organic compound can be used alone or in combination by laminating or mixing two or more kinds.
　有機ケイ素化合物としては、ストレート型ポリシロキサン（ジメチルポリシロキサン、メチル水素ポリシロキサン、メチルメトキシポリシロキサン、メチルフェニルポリシロキサン等）、変性型ポリシロキサン（ジメチルポリシロキサンジオール、ジメチルポリシロキサンジハイドロジェン、側鎖又は両末端アミノ変性ポリシロキサン、側鎖又は両末端又は片末端エポキシ変性ポリシロキサン、両末端又は片末端メタクリル変性ポリシロキサン、側鎖又は両末端カルボキシル変性ポリシロキサン、側鎖又は両末端又は片末端カルビノール変性ポリシロキサン、両末端フェノール変性ポリシロキサン、側鎖又は両末端メルカプト変性ポリシロキサン、両末端又は側鎖ポリエーテル変性ポリシロキサン、側鎖アルキル変性ポリシロキサン、側鎖メチルスチリル変性ポリシロキサン、側鎖カルボン酸エステル変性ポリシロキサン、側鎖フルオロアルキル変性ポリシロキサン、側鎖アルキル・カルビノール変性ポリシロキサン、側鎖アミノ・両末端カルビノール変性ポリシロキサン等）等、又は、それらの共重合体、アミノシラン（アミノプロピルトリエトキシシラン、Ｎ－β（アミノエチル）γ－アミノプロピルトリエトキシシラン、N－フェニル－γ－アミノプロピルトリメトキシシラン等）、エポキシシラン（γ－グリシドキシプロピルトリメトキシシラン、β－（３，４エポキシシクロヘキシル）エチルトリメトキシシラン等）、メタクリルシラン（メタクリロキシプロピルトリメトキシシラン等）、ビニルシラン（ビニルトリエトキシシラン等）、メルカプトシラン（３－メルカプトプロピルトリメトキシシラン等）、クロロアルキルシラン（３－クロロプロピルトリエトキシシラン等）、アルキルシラン（ｎ－ブチルトリエトキシシラン、イソブチルトリメトキシシラン、ｎ－ヘキシルトリメトキシシラン、ｎ－ヘキシルトリエトキシシラン、シクロヘキシルメチルジエトキシシラン、ｎ－オクチルトリメトキシシラン、ｎ－オクチルトリエトキシシラン、ｎ－デシルトリメトキシシラン、ｎ－ヘキサデシルトリエトキシシラン、ｎ－オクタデシルトリメトキシシラン、ｎ－オクタデシルメチルジメトキシシラン等）、フェニルシラン（フェニルトリエトキシシラン等）、フルオロアルキルシラン（トリフルオロプロピルトリメトキシシラン、トリデカフルオロオクチルトリメトキシシラン等）等、又は、それらの加水分解生成物、（３）オルガノシラザン類（ヘキサメチルシラザン、ヘキサメチルシクロトリシラザン等）等が挙げられる。 Examples of organosilicon compounds include straight polysiloxane (dimethylpolysiloxane, methylhydrogen polysiloxane, methylmethoxypolysiloxane, methylphenylpolysiloxane, etc.), modified polysiloxane (dimethylpolysiloxanediol, dimethylpolysiloxane dihydrogen, side Side chain or both ends amino-modified polysiloxane, side chain or both ends or one end epoxy-modified polysiloxane, both ends or one end methacryl-modified polysiloxane, side chain or both ends carboxyl modified polysiloxane, side chain or both ends or one end Carbinol-modified polysiloxane, both-end phenol-modified polysiloxane, side-chain or both-end mercapto-modified polysiloxane, both-end or side-chain polyether-modified polysiloxane, side-chain alkyl-modified polysiloxane, side chain Tilstyryl-modified polysiloxane, side-chain carboxylic acid ester-modified polysiloxane, side-chain fluoroalkyl-modified polysiloxane, side-chain alkyl / carbinol-modified polysiloxane, side-chain amino / both-terminal carbinol-modified polysiloxane, etc.), or the like Copolymer, aminosilane (aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc.), epoxysilane (γ-glycidoxy) Propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc.), methacrylsilane (methacryloxypropyltrimethoxysilane, etc.), vinylsilane (vinyltriethoxysilane, etc.), mercaptosilane (3-mercapto, etc.) Propyltrimethoxysilane, etc.), chloroalkylsilane (3-chloropropyltriethoxysilane, etc.), alkylsilane (n-butyltriethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, (Cyclohexylmethyldiethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-hexadecyltriethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldimethoxysilane, etc.) , Phenylsilane (phenyltriethoxysilane, etc.), fluoroalkylsilane (trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, etc.), etc., or their hydrolysis The product, (3) organosilazanes such (hexamethyldisilazane, hexamethylcyclotrisilazane, etc.) and the like.
　有機金属化合物としては、アミノアルコキシチタニウム（イソプロピルトリ（Ｎ－アミノエチル－アミノエチル）チタネート等）、リン酸エステルチタニウム（イソプロピルトリス（ジオクチルピロホスフェート）チタネート、ビス（ジオクチルピロホスフェート）オキシアセテートチタネート、ビス（ジオクチルピロホスフェート）エチレンチタネート等）、カルボン酸エステルチタニウム（イソプロピルトリイソステアロイルチタネート等）、スルホン酸エステルチタニウム（イソプロピル－ｎ－ドデシルベンゼンスルホニルチタネート等）、チタニウムキレート（チタニウムジイソプロポキシビスアセチルアセトネート、チタニウムジイソプロポキシビスエチルアセトアセテート、オクチレングルコールチタネート等）等）、亜リン酸エステルチタニウム錯体（テトラオクチルビス（ジトリデシルホスファイト）チタネート、テトラ（２，２－ジアリルオキシメチル－１－ブチル）ビス（ジトリデシル）ホスファイトチタネート、テトライソプロピルビス（ジオクチルホスファイト）チタネート等）、カルボン酸エステルジルコニウム（ジルコニウムトリブトキシステアレート等）、ジルコニウムキレート（ジルコニウムトリブトキシアセチルアセトネート等）等）、（３）有機アルミニウム化合物（アルミニウムキレート（アルミニウムアセチルアセトネートジイソプロピレート、アルミニウムエチルアセトアセテートジイソプロピレート、アルミニウムビスエチルアセトアセテートモノアセチルアセトネート、オクタデシレンアセトアセテートアルミニウムジイソプロピレート等）等が挙げられる。 Examples of organometallic compounds include aminoalkoxytitanium (isopropyltri (N-aminoethyl-aminoethyl) titanate, etc.), phosphoric acid ester titanium (isopropyltris (dioctylpyrophosphate) titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (Dioctyl pyrophosphate) ethylene titanate), carboxylic acid ester titanium (isopropyl triisostearoyl titanate, etc.), sulfonic acid ester titanium (isopropyl-n-dodecylbenzenesulfonyl titanate, etc.), titanium chelate (titanium diisopropoxybisacetylacetonate) , Titanium diisopropoxybisethyl acetoacetate, octylene glycol titanate, etc.)), phosphorous Ester titanium complexes (tetraoctyl bis (ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, tetraisopropyl bis (dioctyl phosphite) titanate), carvone Acid ester zirconium (zirconium tributoxy systemate etc.), zirconium chelate (zirconium tributoxyacetylacetonate etc.), etc.) (3) organoaluminum compounds (aluminum chelate (aluminum acetylacetonate diisopropylate, aluminum ethylacetoacetate diisopropylate) Rate, aluminum bisethylacetoacetate monoacetylacetonate, octadecylene acetoacetate aluminum diisopropyl Rate, etc.) and the like.
　ポリオール類としては、トリメチロールプロパン、トリメチロールエタン、ペンタエリスリトール等が挙げられる。 Examples of polyols include trimethylolpropane, trimethylolethane, pentaerythritol and the like.
　アルカノールアミン類としては、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、モノプロパノールアミン、ジプロパノールアミン、トリプロパノールアミン等が挙げられ、その誘導体としては、これらの酢酸塩、シュウ酸塩、酒石酸塩、ギ酸塩、安息香酸塩等の有機酸塩等が挙げられる。 Examples of the alkanolamines include monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, and tripropanolamine. Derivatives thereof include acetates, oxalates, tartrate, and formic acid. Examples thereof include organic acid salts such as salts and benzoates.
　高級脂肪酸類としては、ステアリン酸、ラウリン酸、オレイン酸等が挙げられ、その金属塩としては、これらのアルミニウム塩、亜鉛塩、マグネシウム塩、カルシウム塩、バリウム塩等が挙げられる。 Examples of higher fatty acids include stearic acid, lauric acid, oleic acid and the like, and examples of metal salts thereof include aluminum salts, zinc salts, magnesium salts, calcium salts, barium salts and the like.
　高級炭化水素類としては、パラフィンワックス、ポリエチレンワックス等が挙げられ、その誘導体としては、これらのパーフルオロ化物等が挙げられる。 Examples of higher hydrocarbons include paraffin wax and polyethylene wax, and examples of derivatives thereof include perfluorinated products thereof.
　針状の導電性金属酸化物（例えば、酸化チタン）の粒子表面に無機化合物や有機化合物を被覆する方法は、乾式、湿式を問わず公知のいずれの方法においても実施することが出来る。 The method for coating the surface of particles of a needle-like conductive metal oxide (for example, titanium oxide) with an inorganic compound or an organic compound can be carried out by any known method, whether dry or wet.
１－２－１－３．樹脂
　前記整合層の基材である樹脂は、典型的には、重合性樹脂（成分Ａとする）と重合開始剤（成分Ｂとする）とを含有する樹脂組成物をエネルギー硬化したものである。以下、樹脂の原料となる成分Ａと成分Ｂについて詳述する。 1-2-1-3. Resin The resin which is the base material of the matching layer is typically obtained by energy curing a resin composition containing a polymerizable resin (referred to as component A) and a polymerization initiator (referred to as component B). . Hereinafter, Component A and Component B, which are the raw materials for the resin, will be described in detail.
１－２－１－３－１．成分Ａ
　成分Ａは、特に限定されず、エステル系重合樹脂、ウレタン系重合樹脂、エポキシ系重合樹脂、及びアクリル系樹脂などから選択できる。本発明による電波吸収用粘着シートが、屋外でも使用されることを考慮すると、耐候性が高いアクリル系重合樹脂が好ましい。 1-2-1-3-1. Component A
Component A is not particularly limited, and can be selected from ester-based polymer resins, urethane-based polymer resins, epoxy-based polymer resins, acrylic resins, and the like. Considering that the radio wave absorbing pressure-sensitive adhesive sheet according to the present invention is used outdoors, an acrylic polymer resin having high weather resistance is preferable.
　アクリル系重合性樹脂としては、ビニル基を有するエポキシアクリレート、ウレタンアクリレート、エステルアクリレート、共重合アクリレート、ブタジエンアクリレート、シリコンアクリレート、及び／又はアミノ樹脂アクリレートを用いることが好ましく、より好ましくは、繰り返し単位が２～２０程度のアクリル系オリゴマーであり、末端に２～６個のビニル基を持っているエポキシアクリレート、ウレタンアクリレート、ポリエステルアクリレート、共重合アクリレート、ブタジエンアクリレート、シリコンアクリレート、及び、アミノ樹脂アクリレート等が挙げられるが、中でも３官能以下のものが樹脂の硬化収縮を抑えやすい点において好ましい。 As the acrylic polymerizable resin, it is preferable to use an epoxy acrylate having a vinyl group, a urethane acrylate, an ester acrylate, a copolymer acrylate, a butadiene acrylate, a silicon acrylate, and / or an amino resin acrylate, and more preferably a repeating unit. Epoxy acrylate, urethane acrylate, polyester acrylate, copolymer acrylate, butadiene acrylate, silicon acrylate, amino resin acrylate, etc., which are acrylic oligomers of about 2 to 20 and have 2 to 6 vinyl groups at the ends. Among them, trifunctional or lower functional group is preferable in that it is easy to suppress curing shrinkage of the resin.
　また、これらは単独または２種類以上組み合わせて用いることが可能であり、中でも重量平均分子量が５００～１０，０００、粘度が３，０００～５００，０００ｍＰａ・ｓ／２５℃のウレタンアクリレートが無溶剤系での塗工が容易行える点においてより好ましく、粘度は５，０００～２００，０００ｍＰａ・ｓ／２５℃が更に好ましく、６，０００以上が最も好ましい。粘度が３，０００ｍＰａ・ｓ／２５℃以上であると、針状の導電性酸化物が整合層中で３次元的にランダム分散しやすくなるため、反射減衰性を高め易い効果を奏する。また、無溶剤で整合層を形成できるため残留溶剤の揮発による整合層の寸法変化を抑制しやすくなる。尚、重量平均分子量は、ＪＩＳ　Ｋ７２５２に準拠して、ゲルパーメーションクロマトグラフィー（日本分光株式会社製）を用いて測定される値であり、粘度はＥ型粘度計を用いて測定される値である。 These can be used alone or in combination of two or more. Among them, urethane acrylate having a weight average molecular weight of 500 to 10,000 and a viscosity of 3,000 to 500,000 mPa · s / 25 ° C. is a solvent-free system. The viscosity is more preferably 5,000 to 200,000 mPa · s / 25 ° C., and most preferably 6,000 or more. When the viscosity is 3,000 mPa · s / 25 ° C. or more, the acicular conductive oxide is likely to be randomly dispersed three-dimensionally in the matching layer, so that the reflection attenuation can be easily improved. In addition, since the matching layer can be formed without a solvent, it is easy to suppress the dimensional change of the matching layer due to volatilization of the residual solvent. The weight average molecular weight is a value measured using gel permeation chromatography (manufactured by JASCO Corporation) in accordance with JIS K7252, and the viscosity is a value measured using an E-type viscometer. is there.
１－２－１－３－２．成分Ｂ
　成分Ｂは特に限定されず、選択した成分Ａの重合反応に適したものから、選択することができる。成分Ａをアクリル系樹脂とした場合について、以下に説明する。 1-2-1-3-2. Component B
Component B is not particularly limited and can be selected from those suitable for the polymerization reaction of selected component A. The case where the component A is an acrylic resin will be described below.
　アクリル系重合性樹脂と組み合わせる場合には、有機過酸化物が好ましい。有機過酸化物は、常温から３００℃程度の温度範囲において、無溶剤でアクリル系樹脂組成物を重合硬化させる温度を自由に設定できる点において好適である。上記有機過酸化物としては、メチルエチルケトンパーオキサイド、シクロヘキサンパーオキサイド、３，３，５－トリメチルシクロヘキサノンパーオキサイド、メチルシクロヘキサノンパーオキサイド、メチルアセトアセテートパーオキサイド、アセチルアセトンパーオキサイド、１，１－ビス（ｔ－ブチルパーオキシ）－３，３，５トリメチルヘキサン、１，１－ビス（ｔ－ブチルパーオキシ）－シクロヘキサン、２，２－ビス（ｔ－ブチルパーオキシ）オクタン、ｎ－ブチル－４，４－ビス（ｔ－ブチルパーオキシ）バレート、２，２－ビス（ｔ－ブチルパーオキシ）ブタン、ｔ－ブチルハイドロパーオキサイド、クメンハイドロパーオキサイド、ジ－イソプロピルベンゼンハイドロパーオキサイド、ｐ－メンタンハイドロパーオキサイド、２，５－ジメチルヘキサン－２，５－ジハイドロパーオキサイド、１，１，３，３－テトラメチルブチルハイドロパーオキサイド、１，１，３，３－テトラメチルブチルパーオキシ－２－エチルヘキサネート、ジ－ｔ－ブチルパーオキサイド、ｔ－ブチルクミルパーオキサイド、ジ－クミルパーオキサイド、α，α’－ビス（ｔ－ブチルパーオキシ－ｍ－イソプロピル）ベンゼン、２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキサン、２，５－ジメチル－２，５－ジ（ｔ－ブチルパーオキシ）ヘキシン、アセチルパーオキサイド、イソブチルパーオキサイド、オクタノイルパーオキサイド、デカノイルパーオキサイド、ベンゾイルパーオキサイド、ラウロイルパーオキサイド、ジラウロイルパーオキサイド、３，５，５－トリメチルヘキサノイルパーオキサイド、スクシニックアシッドパーオキサイド、２，４－ジクロロベンゾイルパーオキサイド、ｍ－トルオイルパーオキサイド、ジ－イソプロピルパーオキシジカーボネート、ジ－２－エチルヘキシルパーオキシジカーボネート、ジ－ｎ－プロピルパーオキシジカーボネート、ビス－（４－ｔ－ブチルシクロヘキシル）パーオキシジカーボネート、ジ－ミリスティルパーオキシジカーボネート、ジ－２－エトキシエチルパーオキシジカーボネート、ジ－メトキシイソプロピルパーオキシジカーボネート、ジ（３－メチル－３－メトキシブチル）パーオキシジカーボネート、ジ－アリルパーオキシジカーボネート、ｔ－ブチルパーオキシアセテート、ｔ－ブチルパーオキシイソブチレート、ｔ－ブチルパーオキシピバレート、ｔ－ブチルパーオキシネオデカネート、クミルパーオキシネオデカネート、ｔ－ブチルパーオキシ－２－エチルヘキサネート、ｔ－ブチルパーオキシ－３，５，５－トリメチルヘキサネート、ｔ－ブチルパーオキシラウレート、ｔ－ブチルパーオキシベンゾエート、ジ－ｔ－ブチルパーオキシイソフタレート、２，５－ジメチル－２，５－ジ（ベンゾイルパーオキシ）ヘキサン、ｔ－ブチルパーオキシマレイン酸、ｔ－ブチルパーオキシイソプロピルカーボネート、クミルパーオキシオクテート、ｔ－ヘキシルパーオキシネオデカネート、ｔ－ヘキシルパーオキシピバレート、ｔ－ブチルパーオキシネオヘキサネート、アセチルシクロヘキシルスルフォニルパーオキサイド、ｔ－ブチルパーオキシアリルカーボネート等が挙げられ、これらは単独または２種類以上組み合わせて使用することが出来る。これら有機過酸化物は、ラジカルを発生させ、重合を加速させるが反応終了後は整合層中にはほぼ残留しない。 When combined with an acrylic polymerizable resin, an organic peroxide is preferred. The organic peroxide is suitable in that the temperature at which the acrylic resin composition is polymerized and cured without a solvent can be freely set in a temperature range from room temperature to about 300 ° C. Examples of the organic peroxide include methyl ethyl ketone peroxide, cyclohexane peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (t- Butylperoxy) -3,3,5 trimethylhexane, 1,1-bis (t-butylperoxy) -cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl-4,4- Bis (t-butylperoxy) valate, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, di-isopropylbenzene hydroperoxide, p-menthane hydroperoxide I 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexa , Di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2, 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, Benzoyl peroxide, lauroyl peroxide, dilauroyl peroxide, 3,5,5-to Methyl hexanoyl peroxide, succinic acid peroxide, 2,4-dichlorobenzoyl peroxide, m-toluoyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n- Propyl peroxydicarbonate, bis- (4-tert-butylcyclohexyl) peroxydicarbonate, di-myristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-methoxyisopropyl peroxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, di-allylperoxydicarbonate, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxy Valate, t-butylperoxyneodecanate, cumylperoxyneodecanate, t-butylperoxy-2-ethylhexanate, t-butylperoxy-3,5,5-trimethylhexanate, t-butylper Oxylaurate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butyl Peroxyisopropyl carbonate, cumyl peroxyoctate, t-hexylperoxyneodecanate, t-hexylperoxypivalate, t-butylperoxyneohexanate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyallylcarbonate Etc. These can be used alone or in combination of two or more. These organic peroxides generate radicals and accelerate the polymerization, but hardly remain in the matching layer after the reaction is completed.
１－２－１－３－３．その他の成分
　整合層中には、導電性金属酸化物以外のフィラー成分を添加することも出来る。フィラー成分は、有機・無機を問わないが、有機フィラーである場合には、前記樹脂成分Ａ、Ｂに不溶のものが好ましい。また、無機フィラーである場合には、複素比誘電率の実部が４以下の無機フィラーが好適であり、例としては、水酸化アルミニウム、二酸化珪素等が挙げられる。これらフィラー成分の添加量は、吸収対象となる電磁波、それに対応する針状導電性金属酸化物の添加量等により、任意に設定可能であるが、一般的には樹脂成分に対して、５～２００質量部であり、好ましくは１８～１００質量部である。
　このように整合層中に導電性金属酸化物以外のフィラーを添加することで、整合層中での導電性金属酸化物が３次元的にランダム分散しやすいため、反射減衰性を高め易いという効果を奏する。 1-2-1-3-3. Other Components In the matching layer, filler components other than the conductive metal oxide can be added. The filler component may be organic or inorganic, but when it is an organic filler, it is preferably insoluble in the resin components A and B. Moreover, when it is an inorganic filler, the inorganic filler whose real part of a complex dielectric constant is 4 or less is suitable, and an aluminum hydroxide, silicon dioxide, etc. are mentioned as an example. The addition amount of these filler components can be arbitrarily set depending on the electromagnetic waves to be absorbed, the addition amount of the acicular conductive metal oxide corresponding thereto, etc. The amount is 200 parts by mass, preferably 18 to 100 parts by mass.
By adding fillers other than the conductive metal oxide in the matching layer in this way, the conductive metal oxide in the matching layer is likely to be randomly dispersed three-dimensionally, so that the reflection attenuation can be easily improved. Play.
１－２－１－４．配合
１－２－１－４－１．針状の導電性金属酸化物の配合量
　最も理想的な電磁波吸収性能を得るための、整合層中の（成分Ｃ）の含有量は、吸収目的の電磁波の周波数とこれに応じた複素比誘電率により、任意に決定することができる。すなわち、無反射条件曲線にのるような添加量とすればよい。 1-2-1-4. Formulation 1-2-1-4-1. The amount of acicular conductive metal oxide blended The content of (component C) in the matching layer for obtaining the most ideal electromagnetic wave absorption performance is determined by the frequency of the electromagnetic wave for absorption and the complex relative dielectric corresponding thereto It can be arbitrarily determined by the rate. That is, the addition amount should be such that it falls on the non-reflection condition curve.
１－２－１－４－２．針状の導電性金属酸化物／樹脂の配合比
　針状の導電性金属酸化物と樹脂成分の配合比は、吸収目的の電磁波の周波数とこれに応じた複素比誘電率により、任意に決定することができるが、層を形成する上では、樹脂成分に対して３００質量部未満が好ましい。 1-2-1-4-2. Mixing ratio of acicular conductive metal oxide / resin The mixing ratio of acicular conductive metal oxide and resin component is arbitrarily determined by the frequency of electromagnetic waves for absorption and the complex relative dielectric constant corresponding thereto. However, in forming the layer, the amount is preferably less than 300 parts by mass with respect to the resin component.
１－２－１－４－３．成分Ａ／成分Ｂの比率
　前記成分Ａと、前記成分Ｂの配合について、（成分Ａ/成分Ｂ）で表される質量比は、１０～２，０００であることが好ましく、２０～１，０００であることがより好ましく、３３～２００であることがさらに好ましい。質量比が２，０００を超えると、硬化反応が不十分となり、長期間高温状態におかれた場合に残留未硬化成分の重量減少が起こり、整合層に収縮が生じた結果、電磁波吸収性能が、所望の周波数帯からズレるおそれがある。また、１０未満である場合には、整合層の硬化収縮率が、大きくなり電磁波吸収体を製造する際に層の厚さの調整が難しくなるおそれがある。 1-2-1-4-3. Ratio of Component A / Component B Regarding the blending of Component A and Component B, the mass ratio represented by (Component A / Component B) is preferably 10 to 2,000, preferably 20 to 1,000. More preferably, it is more preferably 33 to 200. When the mass ratio exceeds 2,000, the curing reaction becomes insufficient, the weight of the residual uncured component decreases when left in a high temperature state for a long time, and the matching layer shrinks. There is a risk of deviation from a desired frequency band. On the other hand, if it is less than 10, the curing shrinkage of the matching layer becomes large, and it may be difficult to adjust the thickness of the layer when producing the electromagnetic wave absorber.
１－２－２．粘着層
　粘着層は、金属又は金属酸化物を含有しないこと又は痕跡量程度のみ含有することが好適である。整合層と粘着層との複素比誘電率の差が大きいほど、電波吸収効率は高くなるからである。但し、粘着層に金属が含まれていても、整合層と粘着層の複素比誘電率の差が大きな場合には、電波吸収は可能である。 1-2-2. Adhesive layer It is preferred that the adhesive layer contains no metal or metal oxide or contains only about trace amounts. This is because the radio wave absorption efficiency increases as the difference in complex relative permittivity between the matching layer and the adhesive layer increases. However, even if the adhesive layer contains metal, radio wave absorption is possible if the difference in complex relative permittivity between the matching layer and the adhesive layer is large.
　前記粘着層は、任意の接着剤組成物、または粘着剤組成物から選択できる。具体的には、アクリル系接着剤、シリコーン系接着剤、ウレタン系接着剤、ポリビニルブチラール接着剤（ＰＶＢ）、エチレン－酢酸ビニル系接着剤（ＥＶＡ）等、ポリビニルエーテル、飽和無定形ポリエステル、メラミン樹脂等が挙げられる。 The pressure-sensitive adhesive layer can be selected from any adhesive composition or pressure-sensitive adhesive composition. Specifically, acrylic adhesive, silicone adhesive, urethane adhesive, polyvinyl butyral adhesive (PVB), ethylene-vinyl acetate adhesive (EVA), etc., polyvinyl ether, saturated amorphous polyester, melamine resin Etc.
　粘着層の厚さは、電波吸収用粘着シートとしての構造が維持できればよく、特に制限はないが、一般的には５～１００μｍ、好ましくは５～５０μｍ、より好ましくは１０～２５μｍである。５μｍ未満では十分な粘着力を確保できない可能性があり、１００μｍを超える場合にはシート全体の厚みが増してしまう点で好ましくない。 The thickness of the adhesive layer is not particularly limited as long as the structure as a radio wave absorbing adhesive sheet can be maintained, but is generally 5 to 100 μm, preferably 5 to 50 μm, more preferably 10 to 25 μm. If it is less than 5 μm, there is a possibility that sufficient adhesive strength cannot be secured, and if it exceeds 100 μm, it is not preferable in that the thickness of the entire sheet increases.
１－２－３．剥離性保護フィルム
　本発明に用いられる剥離性保護フィルムの材質は、特に限定されないが、ポリプロピレンフィルム、フッ素樹脂系フィルム、ポリエチレンフィルム、ポリエチレンテレフタレート（ＰＥＴ）フィルム、紙及びこれらにシリコーン樹脂で剥離処理を施したもの（剥離処理フィルム）等が挙げられる。 1-2-3. Peelable protective film The material of the peelable protective film used in the present invention is not particularly limited, but a polypropylene film, a fluororesin-based film, a polyethylene film, a polyethylene terephthalate (PET) film, paper, and a silicone resin are subjected to a peeling treatment. What gave (exfoliation processing film) etc. are mentioned.
　前記剥離性保護フィルムの厚さは、特に限定されないが、１～２００μｍが好ましく、１０～５０μｍがより好ましい。 The thickness of the peelable protective film is not particularly limited, but is preferably 1 to 200 μm, and more preferably 10 to 50 μm.
　前記剥離性保護フィルムは、ピール強度が１．０～５０ｇ／ｃｍが好ましい。１．０ｇ／ｃｍ以下であると、粘着層の製造過程において粘着層と剥離性保護フィルムとが粘着層の硬化途中で剥離し易く、粘着層の表面が不均一になり易い。５０ｇ／ｃｍ以上であると、粘着層と剥離性保護フィルムを剥離する際に、欠損等が生じる恐れがある。 The peelable protective film preferably has a peel strength of 1.0 to 50 g / cm. When it is 1.0 g / cm or less, the adhesive layer and the peelable protective film are easily peeled off during the curing of the adhesive layer in the production process of the adhesive layer, and the surface of the adhesive layer is likely to be uneven. When it is 50 g / cm or more, there is a possibility that defects or the like may occur when the adhesive layer and the peelable protective film are peeled off.
２．電波吸収用粘着シートの製造
　本発明の電波吸収用粘着シートは、種々の公知の方法を利用して製造できる。例えば、ＰＥＴフィルム等に塗工した整合層形成用塗料（整合層の原料を混合した塗料）を硬化させたものと、別のＰＥＴフィルム等に塗工した粘着層形成用塗料（粘着層の原料を混合した塗料）を硬化させたものと、を貼り合わせることで、整合層と、粘着層とを、積層した１組の積層体が形成できる。得られた積層体を複数積層することによって前記電波吸収用粘着シートが得られる。 2. Manufacture of pressure-sensitive adhesive sheet for radio wave absorption The pressure-sensitive adhesive sheet for radio wave absorption of the present invention can be manufactured using various known methods. For example, a coating for forming a matching layer (coating mixed with raw materials for a matching layer) applied to a PET film or the like, and a coating for forming an adhesive layer (raw material for an adhesive layer) applied to another PET film or the like Are bonded together, and a set of laminated bodies in which the matching layer and the adhesive layer are laminated can be formed. The electromagnetic wave absorbing pressure-sensitive adhesive sheet is obtained by laminating a plurality of the obtained laminates.
３．電波吸収用粘着シートの使用方法
　前記電波吸収用粘着シートは、最外層の粘着層を介して、電波反射体である対象物に貼り付けて使用される。電波反射体である対象物と本願電波吸収用粘着シートとが組み合わさることで、整合型電波吸収体として機能する。該最外層の粘着層は、他の粘着層と異なり、貼り付ける対象物に合わせて、変更することができる。 3. Method for Using Radio Wave Absorbing Adhesive Sheet The radio wave absorbing adhesive sheet is used by being attached to an object that is a radio wave reflector via an outermost adhesive layer. The object which is a radio wave reflector and the adhesive sheet for radio wave absorption of the present application are combined to function as a matching type radio wave absorber. Unlike the other adhesive layers, the outermost adhesive layer can be changed in accordance with the object to be attached.
＜＜実施例＞＞
　次に実施例、比較例を用いて本発明の電波吸収用粘着シートをより詳細に説明するが、本発明はこれらの具体例になんら限定されるものではない。 << Example >>
Next, the radio wave absorbing pressure-sensitive adhesive sheet of the present invention will be described in more detail using examples and comparative examples, but the present invention is not limited to these specific examples.
＜整合層の作成方法＞
　重合性樹脂成分：重量平均分子量２，５００、粘度６，５００ｍＰａ・ｓ／２５℃のポリウレタンアクリレート（商品名：「ビームセット５０５Ａ－６」、荒川化学工業社製）１００質量部、重合開始剤成分：１，１，３，３－テトラメチルブチルパーオキシ－２－エチルヘキサネート（商品名：「パーオクタＯ」：日油社製）１．０質量部、に導電性金属酸化物を加え、公知の方法で攪拌して整合層形成用塗料（整合層の原料を混合した塗料）を作成した。得られた塗料をＰＥＴフィルム上に塗工して、整合層を形成した。さらに、整合層露出面にＰＥＴフィルムを貼り合わせ、熱風循環型乾燥機中にて１００℃、１０分間の条件で加熱して整合層を硬化させ、ＰＥＴフィルムを剥離して整合層を得た。 <Matching layer creation method>
Polymerizable resin component: Polyurethane acrylate having a weight average molecular weight of 2,500 and a viscosity of 6,500 mPa · s / 25 ° C. (trade name: “Beam Set 505A-6”, manufactured by Arakawa Chemical Industries Ltd.), 100 parts by mass, polymerization initiator component : 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate (trade name: “Perocta O” manufactured by NOF Corporation), 1.0 wt. The matching layer forming coating material (coating material mixed with the matching layer raw material) was prepared by stirring by the above method. The resulting paint was applied onto a PET film to form a matching layer. Furthermore, the PET film was bonded to the exposed surface of the matching layer, heated in a hot-air circulating drier at 100 ° C. for 10 minutes to cure the matching layer, and the PET film was peeled to obtain a matching layer.
＜粘着層の作成方法＞
　モノマーとしてブチルアクリレート（４２７．３ｇ）、エチルアクリレート（１７１．２ｇ）、４－ヒドロキシブチル（メタ）アクリレート（１．５ｇ）を秤量し、十分に混合して重合性モノマー混合物（ａ１）を得た。次いで、この重合性モノマー混合物（ａ１）３００ｇと酢酸エチル１６０ｇとをフラスコに入れた。また、滴下ロートに３００ｇの重合性モノマー混合物（ａ１）、１６ｇの酢酸エチル及び０．１５ｇの２，２’－アゾビス（４－メトキシ－２，４－ジメチル）バレロニトリルを入れ、よく混合して滴下用混合物（ａ２）を調製した。 <Method for creating adhesive layer>
As monomers, butyl acrylate (427.3 g), ethyl acrylate (171.2 g), 4-hydroxybutyl (meth) acrylate (1.5 g) were weighed and mixed thoroughly to obtain a polymerizable monomer mixture (a1). . Next, 300 g of this polymerizable monomer mixture (a1) and 160 g of ethyl acetate were placed in a flask. Also, add 300 g of the polymerizable monomer mixture (a1), 16 g of ethyl acetate and 0.15 g of 2,2′-azobis (4-methoxy-2,4-dimethyl) valeronitrile in the dropping funnel and mix well. A dropping mixture (a2) was prepared.
　次に、窒素ガスを２０ｍｌ／分で流通させながら、上記フラスコの内温を９５℃まで上昇させ、重合開始剤である２，２’－アゾビス（４－メトキシ－２，４－ジメチル）バレロニトリル（０．１５ｇ）をフラスコに投入し、重合反応を開始させた。そして、このフラスコに滴下ロートから滴下用混合物（ａ２）を９０分掛けて滴下した。滴下用混合物（ａ２）の滴下終了後、粘度の上昇に応じて酢酸エチルで希釈を行いながら、６時間の熟成を行った。反応終了後、重量平均分子量６０万、酸価０ｍｇＫＯＨ／ｇのアクリル系粘着剤ａ３を得た。 Next, while flowing nitrogen gas at 20 ml / min, the internal temperature of the flask was raised to 95 ° C., and 2,2′-azobis (4-methoxy-2,4-dimethyl) valeronitrile as a polymerization initiator was used. (0.15 g) was charged into the flask to initiate the polymerization reaction. And the mixture (a2) for dripping was dripped at this flask over 90 minutes from the dropping funnel. After completion of the dropwise addition of the mixture for dropping (a2), the mixture was aged for 6 hours while being diluted with ethyl acetate as the viscosity increased. After completion of the reaction, an acrylic pressure-sensitive adhesive a3 having a weight average molecular weight of 600,000 and an acid value of 0 mgKOH / g was obtained.
　調整された粘着剤をアプリケーターにて剥離性ＰＥＴフィルム（リンテック製、商品名：ＰＥＴ３８Ｃ）に乾燥後の粘着層の厚さが所望の厚さになるように塗工し、８０℃のオーブン中にて２分間乾燥させ、粘着層を形成した。 The prepared pressure-sensitive adhesive is applied to a peelable PET film (product name: PET38C, manufactured by Lintec Co., Ltd.) with an applicator so that the thickness of the pressure-sensitive adhesive layer after drying becomes a desired thickness. And dried for 2 minutes to form an adhesive layer.
（実施例１）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１６．７質量部を用い、厚さ３５０μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作成した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例１の電波吸収用粘着シートを得た。 Example 1
As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm A matching layer having a thickness of 350 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 1 laminated in two sets.
（実施例２）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１６．７質量部を用い、厚さ２２５μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体３組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせることを繰り返し、３組積層された実施例２の電波吸収用粘着シートを得た。 (Example 2)
As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm A matching layer having a thickness of 225 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Three sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface repeatedly to obtain a radio wave absorbing pressure-sensitive adhesive sheet of Example 2 laminated in three sets.
（実施例３）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１６．７質量部を用い、厚さ１６２μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせることを繰り返し、４組積層された実施例３の電波吸収用粘着シートを得た。 (Example 3)
As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm A matching layer having a thickness of 162 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface, and four sets of laminated radio wave absorbing adhesive sheets of Example 3 were obtained.
（実施例４）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１１．０質量部を用い、厚さ６５４μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例４の電波吸収用粘着シートを得た。 (Example 4)
11.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 654 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorption adhesive sheet of Example 4 in which two sets were laminated.
（実施例５）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）２３．８質量部を用い、厚さ２０５μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例５の電波吸収用粘着シートを得た。 (Example 5)
23.8 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 205 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorption adhesive sheet of Example 5 in which two sets were laminated.
（実施例６）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）３０．０質量部を用い、厚さ１４４μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例６の電波吸収用粘着シートを得た。 (Example 6)
30.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A matching layer having a thickness of 144 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 6 in which two sets were laminated.
（実施例７）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）３１．０質量部を用い、厚さ１３８μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例７の電波吸収用粘着シートを得た。 (Example 7)
31.0 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm is used as the conductive metal oxide used for the matching layer preparation. A matching layer having a thickness of 138 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 7 in which two sets were laminated.
（実施例８）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１６．７質量部と、その他の成分として、平均径1μｍの不定形水酸化アルミニウム（商品名：「ＢＦ０１３」日本軽金属社製）５８．０質量部を用い、厚さ３５０μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、整合層及び剥離性ＰＥＴフィルム上に形成された粘着層を貼り合わせ、１組の積層体を形成した。得られた積層体２組を準備し、一方の整合層面に、他方の粘着層面を貼り合わせ、２組積層された実施例８の電波吸収用粘着シートを得た。 (Example 8)
As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) As other components, 58.0 parts by mass of amorphous aluminum hydroxide having an average diameter of 1 μm (trade name: “BF013” manufactured by Nippon Light Metal Co., Ltd.) was used to form a matching layer having a thickness of 350 μm. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the adhesive layer formed on the matching layer and the peelable PET film was bonded to form a set of laminates. Two sets of the obtained laminates were prepared, and the other adhesive layer surface was bonded to one matching layer surface to obtain a radio wave absorbing adhesive sheet of Example 8 in which two sets were laminated.
（比較例１）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１６．７質量部を用い、厚さ７００μｍの整合層を形成した。粘着層の厚さは２５μｍになるように作製した。このようにして、剥離性ＰＥＴフィルム上に形成された整合層及び粘着層を貼り合わせ、比較例１の電波吸収用粘着シートを得た。 (Comparative Example 1)
As the conductive metal oxide used for producing the matching layer, 16.7 parts by mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm A matching layer having a thickness of 700 μm was formed. The adhesive layer was prepared to have a thickness of 25 μm. In this way, the matching layer and the adhesive layer formed on the peelable PET film were bonded together to obtain the radio wave absorbing adhesive sheet of Comparative Example 1.
（比較例２）
　整合層作製に用いる導電性金属酸化物の代わりに、平均径０．５μｍ、平均長１０．０μｍの非導電性針状酸化チタン（商品名：「ＦＴＬ－４００」石原産業社製）に変更した以外は実施例１と同様にして、比較例２の電波吸収用粘着シートを得た。 (Comparative Example 2)
Instead of the conductive metal oxide used to make the matching layer, it was changed to non-conductive acicular titanium oxide (trade name: “FTL-400” manufactured by Ishihara Sangyo Co., Ltd.) with an average diameter of 0.5 μm and an average length of 10.0 μm. Except for the above, a radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 2 was obtained in the same manner as Example 1.
（比較例３）
　整合層作製に用いる導電性金属酸化物として、平均粒径０．２５μｍの導電性球状酸化チタン（商品名：「ＥＴ－５００Ｗ」石原産業社製）に変更した以外は実施例１と同様にして、比較例３の電波吸収用粘着シートを得た。 (Comparative Example 3)
The same procedure as in Example 1 was conducted except that the conductive metal oxide used for preparing the matching layer was changed to conductive spherical titanium oxide (trade name: “ET-500W” manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 0.25 μm. Thus, an electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 3 was obtained.
（比較例４）
　整合層作製に用いる導電性金属酸化物の代わりに、平均粒径０．５μｍの非導電性不定形チタン酸バリウム（商品名：「ＨＰＢＴ－１」富士チタン社製）に変更した以外は実施例１と同様にして、比較例４の電波吸収用粘着シートを得た。 (Comparative Example 4)
Example except that non-conductive amorphous barium titanate with an average particle size of 0.5 μm (trade name: “HPBT-1” manufactured by Fuji Titanium Co., Ltd.) was used instead of the conductive metal oxide used for the matching layer preparation. In the same manner as in Example 1, a radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 4 was obtained.
（比較例５）
　整合層作製に用いる導電性金属酸化物の代わりに、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）１１．０質量部を用い、厚さ１３３４μｍに変更した以外は比較例１と同様にして、比較例５の電波吸収用粘着シートを得た。 (Comparative Example 5)
11.0 mass of conductive acicular titanium oxide (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm instead of the conductive metal oxide used for the matching layer preparation The electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 5 was obtained in the same manner as Comparative Example 1, except that the thickness was changed to 1334 μm.
（比較例６）
　整合層作製に用いる導電性金属酸化物の代わりに、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）２３．８質量部を用い、厚さ４３４μｍに変更した以外は比較例１と同様にして、比較例６の電波吸収用粘着シートを得た。 (Comparative Example 6)
Instead of the conductive metal oxide used for the matching layer preparation, conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) 23.8 mass The electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 6 was obtained in the same manner as in Comparative Example 1 except that the thickness was changed to 434 μm.
（比較例７）
　整合層作製に用いる導電性金属酸化物として、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）３０．０質量部を用い厚さ３１６μｍに変更した以外は比較例１と同様にして、比較例７の電波吸収用粘着シートを得た。 (Comparative Example 7)
30.0 parts by mass of conductive acicular titanium oxide having an average diameter of 0.5 μm and an average length of 10.0 μm (trade name: “FT-4000” manufactured by Ishihara Sangyo Co., Ltd.) A radio wave absorbing pressure-sensitive adhesive sheet of Comparative Example 7 was obtained in the same manner as Comparative Example 1 except that the thickness was changed to 316 μm.
（比較例８）
　整合層作製に用いる導電性金属酸化物の代わりに、平均径０．５μｍ、平均長１０．０μｍの導電性針状酸化チタン（商品名：「ＦＴ－４０００」石原産業社製）３１．０質量部を用い、厚さ２９９μｍに変更した以外は比較例１と同様にして、比較例８の電波吸収用粘着シートを得た。 (Comparative Example 8)
31.0 mass of conductive acicular titanium oxide (trade name: “FT-4000”, manufactured by Ishihara Sangyo Co., Ltd.) having an average diameter of 0.5 μm and an average length of 10.0 μm instead of the conductive metal oxide used for producing the matching layer The electromagnetic wave absorbing pressure-sensitive adhesive sheet of Comparative Example 8 was obtained in the same manner as in Comparative Example 1, except that the thickness was changed to 299 μm.
（評価）
　得られた実施例１～８及び比較例１～８で作製した電波吸収用粘着シートについて、１５０ｍｍ長×１５０ｍｍ幅の試験片を作成し、それぞれ厚さ５０μｍのアルミ板に貼り付け、整合型電波吸収体として、２０～１１０ＧＨｚ周波数帯域における電波の反射減衰性を測定した。測定には、関東電子応用開発社製の「フリースペース型Ｓパラメータ測定装置」を用い、キーサイトテクノロジー社製の「ＰＮＡネットワークアナライザーＮ５２２５Ａ」で測定した。反射減衰性は、最大電波吸収波長における反射減衰性とした。実施例と比較例とに関する各ピーク吸収波長における反射減衰性の測定値を表１に示す。 (Evaluation)
For the radio wave absorbing pressure-sensitive adhesive sheets prepared in Examples 1 to 8 and Comparative Examples 1 to 8, test pieces having a length of 150 mm and a width of 150 mm were prepared and pasted on an aluminum plate having a thickness of 50 μm, respectively. As an absorber, the return attenuation of radio waves in the 20 to 110 GHz frequency band was measured. For the measurement, “free space type S parameter measuring device” manufactured by Kanto Electronics Application Development Co., Ltd. was used, and measurement was performed by “PNA network analyzer N5225A” manufactured by Keysight Technology. The reflection attenuation is the reflection attenuation at the maximum wave absorption wavelength. Table 1 shows the measured values of reflection attenuation at each peak absorption wavelength for the examples and comparative examples.
（評価結果）
　図３は、実施例１において測定された反射減衰性曲線である。得られた反射減衰曲線のピークは鋭く、周波数選択性が高いことが理解できる。 (Evaluation results)
FIG. 3 is a return attenuation curve measured in Example 1. It can be understood that the peak of the obtained reflection attenuation curve is sharp and the frequency selectivity is high.
　実施例１～３及び比較例１、比較例５～８の結果から、整合層を積層しない場合である比較例１、５～８は、反射減衰性が低く、電波吸収性が低い。積層体の積層数が２組以上では電波吸収性は高くなるが、積層数が３組を超えると、電波吸収性は低下し始めることが理解できる。 From the results of Examples 1 to 3, Comparative Example 1, and Comparative Examples 5 to 8, Comparative Examples 1 and 5 to 8 in which the matching layer is not laminated have low reflection attenuation and low radio wave absorption. It can be understood that, when the number of stacked layers is two or more, the radio wave absorption becomes high, but when the number of stacked layers exceeds three sets, the radio wave absorption starts to decrease.
　さらに実施例１及び８と比較例２～４の結果から、積層したすべての整合層の合計の厚さと単層の整合層の厚さが等しければ、吸収される電波の波長が同一であることが理解できる。 Further, from the results of Examples 1 and 8 and Comparative Examples 2 to 4, if the total thickness of all laminated matching layers is equal to the thickness of the single matching layer, the wavelength of the absorbed radio wave is the same. Can understand.
　比較例２のように、樹脂層に分散固定させるフィラーが針状であっても非導電性である場合には、電波吸収性が著しく低くなることが理解できる。 As in Comparative Example 2, it can be understood that if the filler to be dispersed and fixed in the resin layer is needle-shaped but non-conductive, the radio wave absorption is significantly reduced.
　比較例３及び４のように、前記フィラーが非針状である場合には、フィラーの導電性／非導電性に関わらず、電波吸収性が著しく低くなることが理解できる。 As in Comparative Examples 3 and 4, when the filler is non-needle-like, it can be understood that the radio wave absorptivity is remarkably lowered regardless of the conductivity / non-conductivity of the filler.
　これらの結果から、本発明の電波吸収用粘着シートは、周波数選択性が高く、電波吸収性に優れた整合型電波吸収体の整合層であると言える。
Figure JPOXMLDOC01-appb-I000001
From these results, it can be said that the radio wave absorption pressure-sensitive adhesive sheet of the present invention is a matching layer of a matching type radio wave absorber having high frequency selectivity and excellent radio wave absorption.
Figure JPOXMLDOC01-appb-I000001
１００，２００　　　　　　　　　　　電波吸収用粘着シート
１１０，２１０，２１１，２１２　　　整合層
１２０，２２０，２２１，２２２　　　粘着層
１３０，２３０　　　　　　　　　　　剥離性保護フィルム 100, 200 Adhesive sheet for electromagnetic wave absorption 110, 210, 211, 212 Matching layer 120, 220, 221, 222 Adhesive layer 130, 230 Peelable protective film

Claims (5)

  1. 　針状の導電性金属酸化物が樹脂中に分散固定された整合層と、粘着層と、を積層した積層体を、２組以上積層したことを特徴とする電波吸収用粘着シート。 An electromagnetic wave absorbing pressure-sensitive adhesive sheet characterized by laminating two or more pairs of laminated bodies in which a matching layer in which needle-shaped conductive metal oxides are dispersed and fixed in a resin and a pressure-sensitive adhesive layer are laminated.
  2. 　前記積層体が２組または３組積層されたことを特徴とする請求項１に記載の電波吸収用粘着シート。 2. The radio wave absorbing pressure-sensitive adhesive sheet according to claim 1, wherein two or three sets of the laminates are laminated.
  3. 　前記針状の導電性金属酸化物のアスペクト比が５以上であることを特徴とする請求項１または２に記載の電波吸収用粘着シート。 The electromagnetic wave absorbing pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the needle-like conductive metal oxide has an aspect ratio of 5 or more.
  4. 　前記針状の導電性金属酸化物が導電性針状酸化チタンであることを特徴とする請求項１乃至３のいずれか一項に記載の電波吸収用粘着シート。 4. The radio wave absorbing pressure-sensitive adhesive sheet according to claim 1, wherein the acicular conductive metal oxide is a conductive acicular titanium oxide.
  5. 　前記粘着層には金属および金属酸化物が含まれないことを特徴とする請求項１乃至４のいずれか一項に記載の電波吸収用粘着シート。 5. The radio wave absorbing pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer contains no metal or metal oxide.
PCT/JP2017/009842 2016-03-30 2017-03-10 Radio wave absorbing adhesive sheet WO2017169672A1 (en)

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WO2019082634A1 (en) * 2017-10-24 2019-05-02 株式会社巴川製紙所 Electromagnetic wave absorbing composition and electromagnetic wave absorber
WO2024127495A1 (en) * 2022-12-13 2024-06-20 日本電信電話株式会社 Package

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JP2002223094A (en) * 2001-01-25 2002-08-09 Yokohama Rubber Co Ltd:The Structure of wave absorber
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JP2014078698A (en) * 2012-09-20 2014-05-01 Jsr Corp Electromagnetic wave-absorbing composition and electromagnetic wave absorber

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JP2004027098A (en) * 2002-06-27 2004-01-29 Sumitomo Chem Co Ltd Polypropylene resin composition
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JP2002223094A (en) * 2001-01-25 2002-08-09 Yokohama Rubber Co Ltd:The Structure of wave absorber
WO2008126690A1 (en) * 2007-03-29 2008-10-23 Kabushiki Kaisha Asahi Rubber Electromagnetic shield sheet and rfid plate
JP2014078698A (en) * 2012-09-20 2014-05-01 Jsr Corp Electromagnetic wave-absorbing composition and electromagnetic wave absorber

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019082634A1 (en) * 2017-10-24 2019-05-02 株式会社巴川製紙所 Electromagnetic wave absorbing composition and electromagnetic wave absorber
JP2019079895A (en) * 2017-10-24 2019-05-23 株式会社巴川製紙所 Electromagnetic wave-absorbing composition and electromagnetic wave absorber
JP7000113B2 (en) 2017-10-24 2022-02-04 株式会社巴川製紙所 Electromagnetic wave absorber
WO2024127495A1 (en) * 2022-12-13 2024-06-20 日本電信電話株式会社 Package

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