JP2005277228A - Transparent electromagnetic wave shield and its use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent electromagnetic wave shield in which the silver-gray defects are extremely few even while a silver-containing thin film layer is provided. <P>SOLUTION: For instance, in a transparent conductor composed of a transparent substrate layer and a conductive layer including at least one silver-containing thin film, a transparent resin layer in which the content of halogen and sulfur is ≤50 ppm is formed on the conductive layer by a coating method. The resin layer can be a layer with functions such as a tacky agent layer, an adhesive material layer, a hard coating layer and a toning layer including pigments. Also, the transparent electromagnetic wave shielding case can be suitably used for various kinds of uses of an optical filter, a window, an electromagnetic wave shielding case and a display device, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transparent electromagnetic wave shielding body. More specifically, the present invention relates to a transparent electromagnetic wave shielding body having a thin film layer containing silver.

  In recent years, the development of electronic devices and wireless devices has been remarkable, and the demand has been rapidly increasing. Since electronic devices use electricity, there is a considerable amount of electromagnetic waves that are generated, sometimes causing malfunctions of other devices due to the effects of leaked electromagnetic waves, and others can intercept the electromagnetic waves and read the information. There is a risk that In the case of a wireless device, there is a risk that an electromagnetic wave transmitted can be intercepted and wireless information possessed by the electromagnetic wave can be read. There are also reports that point out that a large amount of recitation of electromagnetic waves affects health.

  In recent years, there has been an increasing demand for electromagnetic shielding materials in order to suppress the influence on other devices and the leakage of information due to these electromagnetic leakages. Electromagnetic waves can be shielded with a conductive material such as metal, but plasma displays (PDP), windows of various buildings and automobile windows, housings for protecting semiconductor components, display parts of various display devices, etc. In addition to the electromagnetic wave shielding function, a material that requires transparency is required. Such materials having electromagnetic wave shielding ability and transparency can be roughly divided into two types. One is called a metal mesh type as reported in Japanese Patent Application Laid-Open No. 10-41679 (Patent Document 1), in which thin metals are arranged in a lattice pattern on a transparent substrate. is there. Although this is excellent in electroconductivity and has an excellent electromagnetic wave shielding ability, there is a problem that a moire image is generated. The other is called a transparent film type as reported in Japanese Examined Patent Publication No. 59-44993 (Patent Document 2), in which a transparent conductive thin film is provided on a transparent substrate. The transparent film type electromagnetic wave shielding material is inferior to the metal mesh type in electromagnetic wave shielding ability, but has a feature that there is no generation of moire images and excellent visibility and transparency.

  In the case of a transparent film type electromagnetic wave shielding body, the electromagnetic wave shielding ability is naturally better as the surface resistance value of the electromagnetic wave shielding body is lower. Therefore, silver or silver having the lowest specific resistance value among pure substances is mainly used. A metal thin film is preferably used as the transparent conductive thin film. Actually, for the purpose of further increasing the transmittance and improving the stability of the metal thin film layer, a transparent conductive thin film is formed by sandwiching the metal thin film layer mainly composed of silver with a transparent high refractive index thin film layer. Is normal.

  However, as is well known, silver that is suitably used as a metal thin film layer material has a great problem that it is very likely to cause aggregation of atoms. Aggregation of silver atoms in the silver thin film layer impairs low resistance as a metal thin film, and also causes silver white defects (also referred to as point defects, reflective defects, or white spots). This silver-white defect significantly reduces the commercial value in appearance and, depending on the defect, may cause loss of the high transparency and low resistance of the metal thin film material.

  Conventionally, it is known that the aggregation of silver atoms in such a silver thin film layer is likely to occur in the presence of, for example, chlorine ions, sulfur ions, foreign matters (particles), etc. It is reported in 2002-304126 (patent document 3). On the other hand, attempts have been made to prevent the aggregation of silver by increasing the thickness of the metal thin film layer as described in JP 2001-57110 A (Patent Document 4). However, in a transparent electromagnetic wave shield requiring high transparency, the thickness of the metal thin film layer is limited, and there is a limit to applying the above method. As another attempt, there is a method of laminating a corrosion-resistant metal thin film such as copper or platinum on a silver thin film layer as described in JP 2000-329931 A (Patent Document 5). There is a problem with a decrease and an increase in sheet resistance.

These countermeasures alone are not sufficient as a countermeasure against silver-white defects, and a transparent electromagnetic wave shield having a configuration capable of easily suppressing the occurrence of silver-white defects has not been obtained so far. For this reason, the reality is that there is room for improvement in yield, productivity, and the like. Therefore, more effective technical development to prevent silver-white defects is required more than ever before.
Japanese Patent Laid-Open No. 10-41679 Japanese Patent Publication No.59-44993 JP 2002-304126 A JP 2001-57110 A JP 2000-329931 A

  Accordingly, an object of the present invention is to provide a transparent electromagnetic wave shielding body in which the above-mentioned silver-white defects are extremely rare.

  As a result of intensive studies from such a viewpoint, the present inventors surprisingly applied a transparent resin having a halogen and sulfur content of 50 ppm or less directly on a conductive layer containing one or more silver-containing thin films, and was transparent. The present inventors have found that the laminate formed with the resin layer is a transparent electromagnetic wave shield with very few silver white defects, and completed the present invention.

According to the present invention, the following inventions are provided.
That is,
(1) a conductive layer (A) including at least one silver-containing thin film;
On the conductive layer (A), a transparent resin layer (B) having a halogen and sulfur content of 50 ppm or less formed by a coating method,
A transparent electromagnetic wave shielding body having an A / B laminated structure is provided. Also,
(2) Preferably, the transparent electromagnetic wave shielding body, wherein the conductive layer (A) including at least one silver-containing thin film is a conductive layer (A1) having a laminated structure including a transparent substrate layer (C),
(3) Preferably, the transparent electromagnetic wave shielding body, wherein the resin layer (B) is a pressure-sensitive adhesive layer (B1),
(4) Preferably, a transparent electromagnetic wave shielding body characterized in that the transparent substrate layer (C) is a transparent film (C1) is provided. The above-mentioned transparent electromagnetic wave shielding body of the present invention has excellent characteristics with few occurrences of silver-white defects.
Moreover, according to the present invention,
(5) A display filter using the transparent electromagnetic wave shielding body is provided. The above-described display filter of the present invention is less susceptible to silver-white defects and has excellent electromagnetic shielding properties and transparency.
Also according to the invention,
(6) A window using the transparent electromagnetic wave shielding body is provided. The window of the present invention has excellent electromagnetic shielding properties and transparency, and is also excellent in workability during its manufacture.
Also according to the invention,
(7) An electromagnetic wave shielding casing using the transparent electromagnetic wave shielding body is provided. The electromagnetic wave shielding casing of the present invention exhibits excellent electromagnetic wave shielding properties and transparency over a long period of time.
Also according to the invention,
(8) A display device using the transparent electromagnetic wave shielding body is provided. The display device of the present invention can provide beautiful images with little generation of electromagnetic waves over a long period of time.

  The transparent electromagnetic wave shielding body of the present invention can generate silver white defects over time and can maintain excellent electromagnetic wave shielding properties, transparency, and appearance over a long period of time. This is the effect of the present invention. For this reason, the industrial significance of the present invention is great.

Hereinafter, the present invention will be described in detail.
The transparent electromagnetic wave shielding body of the present invention comprises a conductive layer (A) containing one or more silver-containing thin films, and a transparent content of halogen and sulfur formed on the conductive layer (A) by a coating method with a content of 50 ppm or less. And a pressure-sensitive adhesive layer (B), and has a laminated structure in the order of A / B. Each of these components will be described below.

(Conductive layer (A) having at least one silver-containing thin film layer)
As the conductive layer (A) having at least one silver-containing thin film layer of the present invention, a known material can be used without limitation. As the conductive layer (A) used in the present invention, a laminate comprising a transparent metal thin film layer (a1) made of silver or an alloy containing silver and a transparent high refractive index thin film layer (a2) is preferably used. . This is because the degree of freedom of design such as transparency, reflection characteristics, and conductivity can be increased by using the above-described configuration. Furthermore, it is one of the reasons that it is easy to suppress the occurrence of silver-white defects described later. FIG. 1 shows an example of a layer structure of a conductive layer (A) having at least one silver-containing thin film layer in the present invention. The conductive layer 10 has a configuration in which three transparent conductive metal thin film layers 11 containing silver and four transparent high refractive index thin film layers 12 are alternately stacked.

As the transparent metal thin film layer (a1), silver has a specific resistance of 1.59 × 10 ⁻⁶ (Ω · cm), which is the most excellent in electrical conductivity among all materials, and the visible light transmittance of the thin film. Therefore, it is most preferably used. On the other hand, silver lacks stability when it is made into a thin film and has the problem of being susceptible to sulfidation and chlorination. Therefore, in order to improve its stability, it contains silver. A silver alloy as a main component, for example, an alloy of silver and gold, an alloy of silver and copper, an alloy of silver and palladium, an alloy of silver, copper and palladium, an alloy of silver and platinum, or the like can also be used.

The thickness of the transparent metal thin film layer (a1) is determined in consideration of the transparency and electrical conductivity of the transparent electromagnetic wave shielding body of the present invention, and is usually about 0.5 to 100 nm per layer. In addition, when the outermost surface of the conductive layer (A) is a transparent metal thin film layer (a1) containing silver, the elemental composition of silver in the outermost surface transparent metal layer is 3 to 99% (atomic ratio). Is preferred. A well-known thing can be used for a transparent high refractive index thin film layer (a2) without a restriction | limiting. A highly transparent material, for example, having a transmittance of 60% or more with respect to light having a wavelength of 400 to 700 nm when a thin film having a thickness of about 100 nm is formed, is preferable. A material having a high refractive index such that the refractive index with respect to light at 550 nm is 1.4 or more is preferable. Examples of materials that can be suitably used for the transparent high refractive index thin film layer (a2) include, for example, oxides of indium and tin (ITO), zinc oxide (ZnO), titanium oxide (TiO ₂ ), cadmium, and the like. Oxide with tin (CTO), aluminum oxide (Al ₂ O ₃ ), oxide with zinc and aluminum (AZO), magnesium oxide (MgO), thorium oxide (ThO ₂ ), tin oxide (SnO ₂ ), oxidation Lanthanum (LaO ₂ ), silicon oxide (SiO ₂ ), indium oxide (In ₂ O ₃ ), niobium oxide (Nb ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ), zirconium oxide (ZrO ₂ ), cesium oxide ( CeO ₂ ), bismuth oxide (BiO ₂ ) and the like are preferably used. A transparent high refractive index sulfide may be used. Specific examples include zinc sulfide (ZnS), cadmium sulfide (CdS), antimony sulfide (Sb ₂ S ₃ ), and the like. Among the above, ITO, ZnO, and TiO ₂ are particularly preferable as the material for the transparent high refractive index thin film layer (a2). This is because ITO and ZnO have electrical conductivity and a refractive index in the visible region is as high as about 2.0, and have almost no absorption in the visible region. TiO ₂ is an insulator and has slight absorption in the visible region, but has a large refractive index with respect to visible light of about 2.3.

  Formation of the multilayer laminate of the transparent metal thin film layer (a1) and the transparent high refractive index thin film layer (a2) can be performed by a conventionally known method such as sputtering, ion plating, or vacuum deposition. Among these, the sputtering method is suitable for forming a multilayer laminated structure that requires film thickness control. This is because a metal thin film layer and a high refractive index thin film layer, for example, a metal thin film layer made of silver or an alloy containing silver and a transparent high refractive index thin film layer mainly composed of indium oxide are easily repeated. This is because the film can be formed and laminated.

  Specifically, for the formation of the transparent metal thin film layer (a1) of the present invention, silver or an alloy containing silver is used as a target, and an inert gas such as argon is used as a sputtering gas. A preferable example is a -3.0 Pa, direct current (DC) or radio frequency (RF) magnetron sputtering method.

  For forming the transparent high refractive index thin film layer (a2), for example, a metal target containing indium as a main component or a sintered body target containing indium oxide as a main component is used, and an inert gas such as argon is used as a sputtering gas. In this case, oxygen is used as a reactive gas, and a reactive sputtering by a normal pressure of 0.01 to 3.0 Pa, direct current (DC) or radio frequency (RF) magnetron sputtering can be applied.

  As the method for measuring the thickness and composition of the thin film of the present invention, a known method can be used without limitation. For other more detailed contents, for example, the contents described in JP-A-10-217380 can be adopted.

(Transparent substrate layer (C))
Since the conductive layer (A) of the present invention is often difficult to handle as a self-supporting film, in the present invention, the conductive layer (A1) having a laminated structure of the transparent substrate layer (C) and the conductive layer (A). It is preferable that Further, the transparent substrate layer (C) is preferably a transparent film (C1) described later. The reason for this is that the conductive layer (A1) can be manufactured by a highly productive method in which the conductive layer (A) is continuously formed on the transparent film (C1) by a roll-to-roll process.

  FIG. 2 shows an example of the conductive layer (A1). The conductive layer as shown in FIG. 2 is obtained, for example, by forming the conductive layer 10 having the structure shown in FIG. 1 on the transparent substrate 20 by a sputtering method.

  As the transparent substrate layer (C), a polymer film, a resin plate, a glass plate, or the like can be used.

  As the polymer film, a flexible and highly transparent polymer film having a thickness of about 10 to 300 μm is preferably used. For example, polyethylene terephthalate (PET), polyimide (PI), polysulfone (PS), polyether Examples include sulfone (PES), polymethylene methacrylate (PMMA), polycarbonate (PC), polyether ether ketone (PEEK), polypropylene (PP), and triacetyl cellulose (TAC). Among these, polyethylene terephthalate (PET) and triacetyl cellulose (TAC) are particularly preferably used.

  As the resin plate, acrylic resin including polymethyl methacrylate (PMMA), polycarbonate resin, transparent ABS resin and the like can be used, but the resin plate is not limited to these resins. The thickness of the resin plate is not particularly limited, but is usually about 1 mm to 10 mm.

  When a glass plate is used, it is desirable to use a semi-tempered glass plate or a tempered glass plate that has been subjected to chemical tempering or air-cooling tempering. Considering the weight, the thickness is preferably about 1 to 4 mm.

  As the transparent substrate layer (C), a transparent film (C1) typified by the polymer film is preferably used.

  Two or more kinds of the above polymer film, plastic plate, glass plate and the like can be used in combination. In this case, these may be directly laminated and combined, or may be used by pasting using a transparent adhesive.

(Resin layer (B))
In the transparent electromagnetic wave shielding body of the present invention, the resin layer (B) is formed on the conductive layer (A) by a coating method. The resin layer (B) of the present invention can be used without limitation as long as it is transparent and the content of halogen and sulfur is 50 ppm or less. Specific examples include acrylic, silicon, urethane, polyvinyl butyral (PVB), ethylene-vinyl acetate, polyvinyl ether, polyester resin, and melamine resin. In this case, it is important that the resin layer (B) has a halogen or sulfur content of 50 ppm or less, preferably 30 ppm or less, more preferably not contained at all, which causes a silver-white defect.

  It must also be transparent to visible light. The light transmittance of the resin layer (B) is preferably 70% or more, more preferably 85% or more.

  Here, the resin layer (B) may be a layer having functions such as a pressure-sensitive adhesive layer, an adhesive layer, and a hard coat as long as the resin as described above is included. As long as these layers satisfy the above requirements, known layers can be applied without limitation.

  The resin layer (B) according to the present invention is characterized in that it is formed by directly coating the conductive layer (A). The resin layer (B) can be a combination of two or more layers or can be laminated. Examples of the coating method include a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a comma coating method, a roll coating method, and the like, which are selected in consideration of the type of adhesive, viscosity, coating amount, and the like. The The thickness of the resin layer (B) is not particularly limited, but is 0.5 to 80 μm, preferably 2 to 40 μm.

  When the resin layer (B) of the present invention is formed by coating, the resin can be used by dissolving in a solvent or dispersing in a dispersion as necessary. On this occasion. As the solvent and dispersion, known substances can be used, but it is preferable not to use substances containing halogen or sulfur.

  On the resin layer (B) of the present invention, a separate film can be attached for the purpose of preventing contamination of foreign matters during storage.

  One preferred form of the resin layer (B) of the present invention is the pressure-sensitive adhesive layer (B1). In the case where the resin layer (B) is used as the pressure-sensitive adhesive layer (B1), it is preferable to bond an easily peelable separate film so as to be stored on a roll. When pasting with other adherends such as a glass plate and a functional transparent film, the separate film can be peeled off and pasted. Of course, after forming the pressure-sensitive adhesive layer (B1), it may be directly bonded to another adherend with a laminator or the like. In that case, in order to improve the characteristic of an adhesive layer (B1), it is preferable to cure at normal temperature or under pressurization and heating.

  In addition, the resin layer (B) of the present invention can have a function of a toning layer by containing a dye, or can contain a rust preventive component. As more specific contents, those described in JP-A-10-217380 can be employed.

(Transparent electromagnetic shield)
The transparent electromagnetic wave shielding body of the present invention is characterized in that the resin layer (B) is formed on the conductive layer (A) by a coating method. FIG. 3 is a cross-sectional view showing an example of the layer structure of the transparent electromagnetic wave shielding body of the present invention. The transparent electromagnetic wave shielding body shown in FIG. 3 is obtained, for example, by forming a resin layer 30 on a conductive layer 10 of a laminate composed of a transparent base layer 20 and a conductive layer 10 by a coating method.

Surprisingly, the transparent electromagnetic wave shielding body of the present invention is remarkably less likely to have the above-mentioned silver-white defects. This is because the transparent electromagnetic wave shield of the present invention is set in a high-temperature and high-humidity treatment apparatus at 60 ° C. and 90% RH, and after 24 hours, a silver white defect having a diameter of 0.4 mm or more is generated due to silver aggregation. The frequency can be confirmed by an accelerated evaluation method that is observed and measured with a loupe. The number of silver-white defects generated by the above evaluation method of the transparent electromagnetic wave shielding body of the present invention is preferably 10 pieces / m ² or less, more preferably 7 pieces / m ² or less, and further preferably 5 pieces / m ² or less. is there. The number of silver-white defects is the average value of the values obtained by observing and measuring three transparent electromagnetic wave shields having an area of 0.5 m ² with a loupe.

  The reason why the occurrence of the above-mentioned silver-white defect is remarkably suppressed is not clear, but the following hypothesis can be made.

  When a pressure-sensitive adhesive sheet is bonded onto a conductive layer, which is one of the methods conventionally used, a slight amount of air may remain between the conductive layer and the pressure-sensitive adhesive layer. On the other hand, in the present invention, since the resin layer (B) is directly coated on the conductive layer (A), the possibility that other components are interposed between the conductive layer (A) and the resin layer (B) is extremely low. In the former case, foreign substances contained in the air in a slight amount may cause the occurrence of a silver-white defect, but in the latter case, the possibility is considered to be extremely low. Furthermore, it is expected that there will be less contamination of foreign matters from the outside. For this reason, it is considered that silver is agglomerated and grown to suppress the occurrence of silver-white defects. Further, it is presumed that when the adhesive is directly coated on the conductive layer (A), a component that aggregates silver is diffused in the resin layer.

  The transparent electromagnetic wave shielding body of the present invention may contain other layers as long as it does not contradict its purpose. For example, other resin layers formed by methods such as pasting, anti-reflection layers, anti-glare layers, anti-fouling layers, hard coat layers, ultraviolet absorption layers, anti-Newton ring layers and other functional transparent layers are included. May be. As another example, a base layer made of a metal other than silver or a metal compound may be formed on the transparent base layer (C) for the purpose of improving the adhesion to the conductive layer (A). Moreover, the transparent layer for improving the adhesiveness may be formed between the transparent metal thin film layer (a1) and the transparent high refractive index thin film layer (a2).

  The light transmittance of the transparent electromagnetic wave shielding material of the present invention varies depending on the application and cannot be specified unconditionally. However, the visible light transmittance in the R3106 standard is preferably 40% or more, and more preferably 50% or more. preferable.

  Since the transparent electromagnetic wave shielding body of the present invention has few silver white defects, it can be suitably used for a display filter. More preferably, it can be used for a filter for plasma display.

  Moreover, the electromagnetic wave shielding body of the present invention can be used for a window by being laminated with a window material such as a glass plate. When the transparent substrate is a glass plate or a resin plate, the electromagnetic shielding body itself can be used as a window material.

  As a method of laminating the window material and the transparent electromagnetic wave shielding body, a method of attaching the surface after wetting the surface with a liquid composed of city water and a surfactant through an adhesive layer is preferably used. . Since the transparent electromagnetic wave shielding body of the present invention has high resistance to chlorine ions contained in city water, etc., even if it is used as a window material, it can be a window having excellent transparency and appearance over a long period of time. . Furthermore, an electromagnetic wave shielding function can be imparted to the window.

  The transparent electromagnetic shielding body of the present invention can also be used for an electromagnetic shielding housing. Specific examples of the electromagnetic wave shielding housing include a housing for covering a memory such as a ROM and a semiconductor component such as a microprocessor. Since the semiconductor component used in this electromagnetic wave shielding casing has few malfunctions due to electromagnetic waves and is excellent in visibility, it is possible to detect abnormal appearance of the electric circuit without removing the electromagnetic shielding casing.

  The transparent electromagnetic wave shielding body of the present invention can be used in various display devices such as liquid crystal display devices, plasma displays, and cathode ray tube televisions. Since the transparent electromagnetic wave shielding body of the present invention has very few silver-white defects, it can provide a bright and beautiful image with little leakage of electromagnetic waves over a long period of time.

Hereinafter, the present invention will be described by way of examples. The present invention is not limited by these.
[Example 1]
(Formation of transparent conductive film)
A transparent conductive film having the same layer structure as that of FIG. 2 was produced by the following method. That is, a polyethylene terephthalate (hereinafter referred to as PET) film (thickness 75 μm) is used as a transparent substrate, and an ITO thin film layer (transparent) made of an oxide of indium and tin is formed on one main surface thereof by using a direct current magnetron sputtering method. A high refractive index thin film layer) and a silver thin film layer (transparent metal thin film layer) were sequentially laminated to obtain a transparent film. The composition of the transparent conductive film was transparent substrate (75 μm) / ITO (40 nm) / Ag (15 nm) / ITO (80 nm) / Ag (20 nm) / ITO (80 nm) / Ag (15 nm) / ITO (80 nm). .
Here, for the formation of the ITO thin film layer, an indium oxide / tin oxide sintered body [In ₂ O ₃ : SnO ₂ = 90: 10 (mass ratio)] as a target, and an argon / oxygen mixed gas (total) as a sputtering gas Pressure 266 mPa, oxygen partial pressure 5 mPa). In forming the silver thin film layer, silver was used as a target, and argon gas (total pressure 266 mPa) was used as a sputtering gas.

(Thin film thickness)
The thickness of the ITO thin film layer and the silver thin film layer of the above thin film is obtained in advance by determining the relationship between the film forming time when the ITO thin film layer and the silver thin film layer are formed under the above film forming conditions and the layer thickness to be formed. In addition, the film formation time was controlled.

(Formation of adhesive layer)
Subsequently, an acrylic pressure-sensitive adhesive (BPS 6060 manufactured by Toyo Ink) was applied to the conductive layer side of the transparent conductive film with a comma coater to form a pressure-sensitive adhesive layer having a thickness of 25 μm. This film and a PET film (thickness 25 μm) were bonded together with a laminator to obtain a transparent electromagnetic wave shielding film. Further, the halogen and sulfur contents of this acrylic pressure-sensitive adhesive were decomposed by a combustion gas absorption method and measured with an ion chromatograph (DX-500 manufactured by Dionex).

(Acceleration test, evaluation)
The transparent electromagnetic wave shielding film obtained as described above is set in a high-temperature and high-humidity treatment apparatus at 60 ° C. and 90% RH, and after 24 hours, a silver white defect having a diameter of 0.4 mm or more caused by silver aggregation. The occurrence frequency was observed and measured with a loupe.
These results are shown in Table 1.

[Example 2]
A transparent conductive film was prepared in the same manner as in Example 1, and then a polyester hot melt adhesive (GK640 manufactured by Toyobo Co., Ltd.) was applied to the conductive layer side of this transparent conductive film with a gravure reverse coater. A 5 μm adhesive layer was formed. This film and a PET film (thickness 25 μm) were laminated by applying heat at a temperature of 120 ° C. with a laminator to obtain a transparent electromagnetic wave shielding film. Moreover, the halogen and sulfur contents of this polyester adhesive were 13 ppm and 3 ppm, respectively.
The frequency of occurrence of a silver-white defect in the transparent electromagnetic wave shielding film thus prepared was measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3
A transparent conductive film was prepared in the same manner as in Example 1, and then an acrylic pressure-sensitive adhesive (SK1435 manufactured by Soken Chemical Co., Ltd.) was applied to the conductive layer side of this transparent conductive film with a die coater. A layer was formed. This film and a glass plate (thickness 3 mm) were bonded using water with a roller to obtain a transparent electromagnetic wave shielding body. The halogen and sulfur contents of this acrylic pressure-sensitive adhesive were 23 ppm and 3 ppm, respectively.
The frequency of occurrence of a silver-white defect in the transparent electromagnetic wave shielding film thus prepared was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
A transparent conductive film was prepared in the same manner as in Example 1.
Separately, an acrylic pressure-sensitive adhesive (BPS 6060 manufactured by Toyo Ink Co., Ltd.) was applied to the easy peelable layer side of the separate film [thickness 25 μm] with a comma coater to form a pressure-sensitive adhesive layer having a thickness of 25 μm. The adhesive film and the conductive layer side of the transparent conductive film were bonded together with a laminator to obtain a transparent electromagnetic wave shielding film.
The frequency of occurrence of a silver-white defect in the transparent electromagnetic wave shielding film thus prepared was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
A transparent conductive film was prepared in the same manner as in Example 1. A small amount of NaCl was added to an acrylic pressure-sensitive adhesive (BPS 6060 manufactured by Toyo Ink), and this pressure-sensitive adhesive was applied to a transparent conductive film with a comma coater to form a pressure-sensitive adhesive layer having a thickness of 25 μm. This film and a PET film (thickness 25 μm) were bonded together with a laminator to obtain a transparent electromagnetic wave shielding film. The acrylic adhesive had halogen and sulfur contents of 70 ppm and 5 ppm, respectively.
The frequency of occurrence of a silver-white defect in the transparent electromagnetic wave shielding film thus prepared was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
A transparent conductive film was prepared in the same manner as in Example 1. A small amount of sulfur was added to an acrylic pressure-sensitive adhesive (BPS 6060 manufactured by Toyo Ink), and this pressure-sensitive adhesive was applied to a transparent conductive film with a comma coater to form a pressure-sensitive adhesive layer having a thickness of 25 μm. This film and a PET film (thickness 25 μm) were bonded together with a laminator to obtain a transparent electromagnetic wave shielding film. The halogen and sulfur contents of this acrylic pressure-sensitive adhesive were 30 ppm and 82 ppm, respectively.
The frequency of occurrence of a silver-white defect in the transparent electromagnetic wave shielding film thus prepared was measured in the same manner as in Example 1. The results are shown in Table 1.

  As is clear from Table 1, when a transparent conductive shield is formed, by forming a resin layer such as a pressure-sensitive adhesive layer or an adhesive layer directly on the conductive layer, the frequency of occurrence of silver-white defects due to silver aggregation can be reduced. It turns out that it has fallen significantly.

It is a figure which shows an example of the laminated constitution of the conductive layer in this invention. It is a figure which shows an example of the laminated constitution of the transparent conductor in this invention. It is sectional drawing which shows an example of the laminated constitution of the transparent electromagnetic wave shielding body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Conductive layer 11 Transparent conductive metal thin film layer 12 containing silver Transparent high refractive index thin film layer 20 Transparent substrate 30 Resin layer

Claims (8)

A conductive layer (A) comprising at least one silver-containing thin film;
On the conductive layer (A), a transparent resin layer (B) having a halogen and sulfur content of 50 ppm or less formed by a coating method,
A transparent electromagnetic wave shielding body having a laminated structure of A / B.   The transparent electromagnetic wave shielding body according to claim 1, wherein the conductive layer (A) including at least one silver-containing thin film is a conductive layer (A1) having a laminated structure including a transparent substrate layer (C).   The transparent electromagnetic wave shielding body according to claim 1, wherein the resin layer (B) is an adhesive layer (B1).   The transparent electromagnetic wave shielding body according to claim 2, wherein the transparent substrate layer (C) is a transparent film (C1). A display filter using the transparent electromagnetic wave shielding body according to claim 1. A window using the transparent electromagnetic wave shielding body according to claim 1. An electromagnetic wave shielding casing using the transparent electromagnetic wave shielding body according to claim 1. A display device using the transparent electromagnetic wave shielding body according to claim 1.

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