JP2008041765A - Electromagnetic wave shielding/light transmitting window material, and its production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for producing an electromagnetic wave shielding/light transmitting window material in which a conductive pattern of small and uniform linewidth can be formed stably, and to provide an electromagnetic wave shielding/light transmitting window material produced by that method. <P>SOLUTION: A metal oxide thin film 2 is formed on the surface of a transparent substrate 1. A print pattern 3 is formed on the metal oxide thin film 2 by spraying ink containing an electroless plating catalyst from an ink jet head. When immersion of the transparent substrate 1 is performed in a plating bath; plating metal is deposited using a catalyst particle as a nucleus, and a conductive pattern 5 is formed of an electroless plating layer 4. Since ink is printed by ink jet method, a print pattern of small and uniform linewidth can be formed stably. Since the conductive pattern copies the print pattern, a conductive pattern of small and uniform linewidth can be formed stably on the print pattern. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave shielding light transmission window material useful as a front filter of a plasma display panel (PDP), a window material of a building requiring an electromagnetic wave shield such as a hospital (for example, a sticking film), and a manufacturing method thereof. In particular, the present invention relates to an electromagnetic wave shielding light-transmitting window material formed by forming a conductive pattern on a transparent substrate by electroless plating and a method for manufacturing the same.

  In recent years, with the spread of OA equipment, communication equipment, etc., electromagnetic waves generated from these equipment have been regarded as a problem. That is, there are concerns about the influence of electromagnetic waves on the human body, and malfunctions of precision equipment due to electromagnetic waves are problematic.

  Thus, conventionally, a window material having an electromagnetic shielding property and a light transmission property has been developed and put into practical use as a front filter of a PDP of an OA device. Such a window material is also used as a window material for a precision device installation place such as a hospital or a laboratory in order to protect the precision device from electromagnetic waves such as a mobile phone.

  Conventional electromagnetic shielding light-transmitting window materials are mainly configured by integrating a conductive mesh material such as a wire mesh between transparent substrates such as acrylic plates.

  The conductive mesh used for the conventional electromagnetic shielding light transmitting window material is generally about 5 to 500 mesh with a wire diameter of 10 to 500 μm, and the aperture ratio is less than 75%.

  As for the conductive mesh used conventionally, generally the thing of the wire diameter of the conductive fiber which comprises a mesh is coarse, and when a wire diameter becomes thin, it will become fine. This is because if the fiber has a large wire diameter, it is possible to form a coarse mesh, but it is very difficult to form a coarse mesh with a thin wire diameter.

  For this reason, in the conventional electromagnetic wave shielding light transmission window material using such a conductive mesh, even if the light transmittance is good, it is at most about 70%, and it is not possible to obtain good light transmittance. was there.

  In addition, the conventional conductive mesh has a problem that moire (interference fringes) is likely to occur due to the pixel pitch of the light emitting panel to which the electromagnetic wave shielding light transmitting window material is attached.

  In order to solve such a problem, it has been proposed to form a conductive pattern using a pattern printing method. For example, Japanese Patent Application Laid-Open No. 11-170420 discloses an electroless plating on the surface of a transparent substrate. It has been proposed to form a conductive pattern by forming a printed pattern with a paste containing a catalyst and depositing a conductive material on the printed pattern by electroless plating. According to pattern printing, a printed pattern including an electroless plating catalyst can be formed into a desired pattern shape, and a plating layer can be deposited thereon to form a desired conductive pattern. The degree of freedom of the mesh shape is remarkably larger than that of the conductive mesh, and even a grid-like conductive pattern with a thin line having a line width of 200 μm or less and an aperture ratio of 75% or more and a high aperture ratio can be easily formed. And if it is an electromagnetic wave shielding light transmissive window material in which a conductive pattern having a coarse mesh is formed with such fine wires, it is possible to obtain good light transmittance and to prevent the moire phenomenon. The aperture ratio is obtained by calculation from the line width of the mesh and the number of lines existing in 1 inch width.

  Specifically, in the method described in JP-A No. 11-170420, a printing paste containing electroless plating catalyst particles, a resin component as a binder, a solvent, and other additives is pattern-printed by a screen printing method, After the printed pattern is cured, a plating layer is deposited by electroless plating.

In addition, when forming a conductive pattern using a pattern printing method, an organic substance is anchor-coated on the transparent base material in order to improve the adhesion between the transparent base material and the conductive pattern. A conductive pattern is printed on the substrate.
JP 11-170420 A

  As described in JP-A-11-170420, when printing paste containing electroless plating catalyst particles is printed by a screen printing method, the screen eyes are apt to be collapsed, so that a print pattern with a small line width and a uniform line width is formed. It is difficult to form stably. Therefore, even in the conductive pattern formed by electroless plating on the printed pattern, it is difficult to stably form a conductive pattern having a small line width and a uniform line width. .

  In addition, every time the printing pattern is changed, it is necessary to re-create the screen printing plate, which causes a problem that it is complicated.

  The present invention provides a method for manufacturing an electromagnetic wave shielding light-transmitting window material capable of stably forming a uniform conductive pattern with a small line width, and an electromagnetic wave shielding light transmitting window material manufactured by this method. This is the first purpose.

  In addition, when an organic substance is anchor-coated on a transparent substrate, a pretreatment process (soft etching, smut removal, pre-dip process, etc.) for forming a printing paste on the anchor coating layer, an electroless plating process, etc. However, there is a problem that the anchor coating layer is immersed in an acidic or alkaline solution and becomes brittle, and the adhesiveness of the conductive pattern deteriorates.

  The present invention provides a method for producing an electromagnetic wave shielding light transmissive window material capable of firmly attaching a conductive pattern on a transparent substrate, and an electromagnetic wave shielding light transmissive window material produced by this method. Second purpose.

  The method for producing an electromagnetic wave shielding light transmissive window material according to claim 1 includes: an electromagnetic wave shielding light transmissive window material comprising a transparent substrate and a conductive pattern formed on the surface of the transparent substrate by electroless plating. A method of manufacturing, wherein a step of printing an ink containing an electroless plating catalyst on the surface of the transparent substrate to form a printed pattern, and then conducting the electroless plating treatment to conduct electricity on the printed pattern In the method of manufacturing an electromagnetic wave shielding light-transmitting window member comprising a step of forming a conductive pattern by adhering a material, the ink is printed by an inkjet method.

  The manufacturing method of the electromagnetic wave shielding light transmission window material of Claim 2 forms a metal oxide thin film or a metal thin film on the surface of the said transparent base material in Claim 1, and on this metal oxide thin film or a metal thin film. The ink is printed.

  The method for producing an electromagnetic wave shielding light-transmitting window material according to claim 3 is the method according to claim 2, wherein the surface of the transparent substrate is surface-treated by a corona method or plasma discharge, and then the metal oxide thin film or the metal thin film is formed. It is characterized by this.

  According to a fourth aspect of the present invention, there is provided the method for producing an electromagnetic wave shielding light transmitting window material according to the second or third aspect, wherein the metal oxide thin film or the metal thin film has conductivity.

  According to a fifth aspect of the present invention, there is provided the method for producing an electromagnetic wave shielding light-transmitting window material according to any one of the first to fourth aspects, further comprising performing an electrolytic plating process on the conductive pattern.

  According to a sixth aspect of the present invention, there is provided a method for producing an electromagnetic wave shielding light-transmitting window material according to any one of the first to fifth aspects, wherein the printed pattern is formed in a lattice shape.

  The method for producing an electromagnetic wave shielding light-transmitting window material according to claim 7 is characterized in that, in claim 6, the line width of the conductive pattern is 200 μm or less and the aperture ratio is 75% or more. .

  An electromagnetic wave shielding light-transmitting window material according to an eighth aspect is manufactured by the method according to any one of the first to seventh aspects.

  According to the present invention, since the ink containing the electroless plating catalyst is printed by the ink jet method, a print pattern having a small line width and a uniform line width can be stably formed. Since the conductive pattern follows the printed pattern, a conductive pattern having a small line width and a uniform line width can be stably formed on the printed pattern.

  In the present invention, in order to improve the adhesion between the transparent substrate and the ink, a metal oxide thin film or a metal thin film is formed on the surface of the transparent substrate as an anchor coating, and the metal oxide thin film or the metal thin film is formed on the metal oxide thin film or the metal thin film. It is preferable to print ink. This metal oxide thin film or metal thin film is excellent in alkali resistance and acid resistance as compared with an organic substance, and hardly deteriorates by an electroless plating solution. Therefore, the conductive pattern can be firmly adhered on the transparent substrate.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of a method for producing an electromagnetic wave shielding light transmitting window material of the present invention. First, a transparent substrate 1 is prepared (FIG. 1 (a)). In the present embodiment, the surface of the transparent substrate 1 is subjected to surface treatment by corona method or plasma discharge, and then the metal oxide thin film 2 is formed on the surface of the transparent substrate 1 (FIG. 1B). An ink containing an electroless plating catalyst is sprayed on the metal oxide thin film 2 from an ink jet head to form a printed pattern 3 (FIG. 1C).

  And the transparent base material 1 which formed the printing pattern 3 in this way is used for an electroless-plating process. In this electroless plating treatment, when the transparent substrate 1 is immersed in a plating bath, a plating metal is deposited with the electroless plating catalyst particles exposed on the surface of the printed pattern 3 as a nucleus, and from the electroless plating layer 4 A conductive pattern 5 is formed. Thereby, the electromagnetic wave shielding light transmission window material in which the conductive pattern 5 is formed on the transparent base material 1 is obtained (FIG. 1D).

  In the present invention, the constituent material of the transparent substrate 1 is not particularly limited as long as it is excellent in erosion resistance to the plating bath, and is not limited to glass, polyester, polyethylene terephthalate (PET), polybutylene terephthalate, polymethyl. Methacrylate (PMMA), acrylic plate, polycarbonate (PC), polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinked ethylene-methacryl Acid copolymers, polyurethane, cellophane, etc., preferably PET, PC, PMMA.

  The thickness of the transparent substrate 1 is appropriately determined depending on the required characteristics (for example, strength and lightness) depending on the use of the obtained window material, but is usually in the range of 1 μm to 5 mm. A transparent film of about ˜200 μm is preferable for reducing the thickness and weight of the electromagnetic shielding light transmitting window material.

The constituent material of the metal oxide thin film 2 is not particularly limited as long as it is excellent in corrosion resistance to a plating bath and excellent in adhesion of an ink containing an electroless catalyst. For example, in order to make the metal oxide thin film 2 a transparent thin film having conductivity, ITM (In-S), ITO (In ₂ O ₃ + SnO ₂ ), Zn, ZnO, Sn, ZnO + Al ₂ O ₃ , SnO _{2 , Sn-Sb, SnO 2 -SbO} 3, ZnS + Mn, ZnS + Si, ZnS + Ti, ZnS + Fe, ZnS + SnS, ZnS + Ni, ZnS + Co, ZnS + Pd, ZnS + Sn, ZnS + Cu, ZnS + Ge, ZnS + Ag, ZnS + In, ZnS, TbF 3, ZnS + SmF 3, ZnS + Tb 4 O 7, It is preferable to use CaS + Ag or the like. Thus, when the metal oxide thin film 2 has conductivity, the electromagnetic wave shielding property of the obtained electromagnetic wave shielding light transmitting window material is further improved.

  This metal oxide thin film 2 can be formed by vapor phase methods such as sputtering, ion plating, vacuum deposition, chemical vapor deposition, gravure coating, micro gravure coating, dao coating, lip coating, roll reverse coating, wire bar coating, kiss coating, and screen printing. It can be formed by a coating method such as ink jet printing, blade coating, roll coating, dip coating or spin coating.

  The total light transmittance of the metal oxide thin film 2 is preferably 70% or more.

  The ink of the printed pattern 3 contains a resin component as a binder and electroless plating catalyst particles. As the resin component, the adhesion to the metal oxide thin film 2 can be secured, and after curing, An alkali-resistant resin component excellent in erosion resistance against an electroless plating bath is preferable, and a reactive acrylate and / or methacrylate is particularly preferable. The resin component may be a monomer or an oligomer, and it is preferable to appropriately adjust the blending amount of the monomer and the oligomer and the molecular weight of the oligomer according to the viscosity required for the ultraviolet curable resin paste. .

  As electroless plating catalyst particles, noble metal particles such as Pd, Au, Ag, and Pt, metal particles such as Cu, or metal oxide particles such as ITO (indium tin oxide) can be used. These catalyst particles may be used alone or in a combination of two or more.

  The blending amount of the catalyst particles is appropriately determined depending on the type of catalyst particles used, but is generally in the range of 10 to 700 parts by weight with respect to 100 parts by weight of the resin component. Among the above catalyst particles, Pd is required in a small amount, and may be, for example, about 10 to 50 parts by weight with respect to 100 parts by weight of the resin component, which is advantageous in terms of reducing the blending amount of the catalyst particles.

  When the catalyst particles used have a large particle size, a homogeneous plating layer cannot be obtained. Therefore, the catalyst particles are fine particles having a particle size of 1 μm or less, particularly 0.1 μm or less, for example, an average particle size of about 3 to 500 nm. preferable.

  In addition to the above components, the ink used in the present invention may further contain a dispersant such as a surfactant, if necessary, about 0 to 10 parts by weight with respect to 100 parts by weight of the resin component.

  In addition, the ink used in the present invention may contain a solvent as necessary for viscosity adjustment. In this case, the solvent is about 0 to 50 parts by weight with respect to 100 parts by weight of the resin component. Is preferred. That is, in the present invention, it is possible to use ink that does not substantially use a solvent, but a solvent may be used. Even in the case of using a solvent, it is possible to reduce the blending amount compared with conventional general inks. This enables heat drying treatment after printing, dripping during heating, tact time (heating) Time) problem can be solved.

  In addition, it is preferable that the prepared ink is processed with a mesh having an appropriate opening prior to printing to remove coarse particles and the like.

  In the present invention, the thickness of the printing pattern 2 is preferably 0.1 to 1.0 μm.

  This electroless plating treatment can be performed according to a conventional method using a normal electroless plating bath. As the plating metal, that is, the conductive material constituting the conductive pattern 5, a metal or an alloy such as aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, and zinc is used. Of these, pure metals or alloys of copper, nickel, chromium, zinc, tin, silver or gold are preferred among these. Therefore, for example, an electroless Cu plating bath, an electroless Ni—P plating bath, an electroless Ni—B plating bath, an electroless Au plating bath, or the like can be used.

  By this electroless plating treatment, the plating metal is deposited with the electroless plating catalyst particles exposed on the surface of the printed pattern 3 as nuclei, and the conductive pattern 5 made of the plating layer 4 is formed.

  If the thickness of the conductive pattern 5 formed in this way is too thin, the electromagnetic wave shielding performance is insufficient, which is not preferable. On the other hand, if it is too thick, it affects the thickness of the electromagnetic wave shielding light-transmitting window material obtained and narrows the viewing angle. Further, since the plating spreads in the width direction, the line width is increased and the aperture ratio is lowered. Therefore, the thickness of the conductive pattern 5 is preferably about 0.1 to 10 μm.

  As shown in FIG. 1E, after the formation of the conductive pattern 5 by electroless plating, the surface of the conductive pattern 5 may be blackened to form the antiglare layer 6. As a blackening method, an oxidation treatment of a metal film, a black plating treatment of a chromium alloy, or the like can be employed.

  The conductive pattern 5 thus formed preferably has a lattice shape with a line width of 200 μm or less, particularly preferably 100 μm or less, particularly 30 μm or less, and an aperture ratio of 75% or more. The pattern printing is preferably performed so that the conductive pattern 5 is formed.

  The electromagnetic shielding light-transmitting window material produced in this way may be composed of a single film, particularly when a transparent film is used as a base material, and may be a continuous web-like material unwound from a roll. It may be a film.

  The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, as shown in FIG. 2, after the electroless plating layer 4 is formed, the electroplating layer 4a is formed thereon, and the electroconductive pattern 5 is formed by the electroless plating layer 4 and the electroplating layer 4a. May be.

  In the said embodiment, although the metal oxide thin film 2 was formed on the transparent base material 1, you may abbreviate | omit and you may replace with this metal oxide thin film 2, and may form a metal thin film. Examples of the metal thin film include those formed by applying Au-Ag ink.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

Example 1
By the following method, an electromagnetic wave shielding light transmission window material having a structure shown in FIG. In addition, as the transparent base material 1, the transparent polyester film (Teijin O3LF8, thickness 125 micrometers) was used.

[Production of Metal Oxide Thin Film 2]
The surface of the transparent substrate 1 was subjected to a corona discharge treatment for 3 seconds at an applied voltage of 150 V and a current of 15 A using a corona discharge treatment apparatus manufactured by Kasuga Electric Co., Ltd.

Then, by electron-beam evaporation to form a metal oxide thin film 2 made of SiO ₂ thin film on the surface of the transparent substrate 1. As an apparatus, an electron beam vapor deposition apparatus (EGL-35M; manufactured by ULVAC, Inc.) was used, and vapor deposition was performed under conditions of 5 × 10 ⁻⁶ torr. The average film thickness of the obtained SiO ₂ thin film was 0.5 μm, and the total light transmittance was 80%.

[Preparation of Print Pattern 3]
50 ml of an inducer containing a palladium catalyst (OPC-50; manufactured by Okuno Pharmaceutical Co., Ltd.), 50 ml of water, and 100 ml of glycerin were mixed to prepare an ink having a viscosity of 15 mPas (temperature 25 ° C.). Using this ink, a mesh shape pattern (line width 30 μm, 100 mesh) was drawn by an inkjet device, dried at 40 ° C. for 6 minutes, and then washed with water. Thereby, the printing pattern 3 was obtained.

  As an ink jet device, an ink jet type coating device (MJP-1500V) manufactured by Microjet Co., Ltd. was used.

[Electroless plating treatment]
By immersing the transparent substrate 1 on which the printed pattern 3 is formed in the first pretreatment liquid (temperature 25 ° C.) for 5 minutes, and then immersing in the second pretreatment liquid (temperature 25 ° C.) for 1 minute. Then, a treatment for reducing the palladium nucleus in the printed pattern 3 to facilitate the deposition of electroless plating was performed. The first pretreatment liquid and the second pretreatment liquid are as follows.

First pretreatment liquid
OPC-150 Cryster MU (Okuno Pharmaceutical Co., Ltd.): 150ml
Water: 1000ml
Second pretreatment liquid
OPC-150 Cryster MU (Okuno Pharmaceutical Co., Ltd.): 30ml
Water: 1000ml
Then, it was immersed in the following electroless copper plating bath and electroless copper plating was performed at 60 ° C. for 80 minutes to form a conductive pattern 5 having a thickness of 4 μm.

Electroless copper plating bath
OPC Copper J1 (Okuno Pharmaceutical Co., Ltd.): 80ml
Water: 1000ml
OPC Copper J2 (Okuno Pharmaceutical Co., Ltd.): 55ml
Water: 1000ml
Electroless copper RH: 25ml
Water: 1000ml

[Anti-glare treatment]
The sample was washed with water and dried, and then an anti-glare layer 6 was formed by printing black ink on the conductive pattern 5 using the same ink jet apparatus as described above.

[Measurement of aperture ratio (%)]
Using a Hitachi spectrophotometer (U-4000; manufactured by Hitachi, Ltd.), the light transmittance at a wavelength of 550 nm was measured, and the aperture ratio was determined by canceling the loss due to reflection at the air interface.

[Measurement of reflectance]
Using a Hitachi spectrophotometer (U-4000; manufactured by Hitachi, Ltd.), 5 ° specular reflection measurement of light having a wavelength of 550 nm was performed, and the visible light reflectance of the sample was determined with the reflectance of the mirror mirror being 100%.

[Measurement of surface resistance]
The surface resistance value was measured by the four probe method.

  In Example 1, the aperture ratio was 80%, the reflectance was 10%, and the surface resistance value was 0.5Ω / □.

Example 2
Example 1 except that an ITO thin film was formed as the metal oxide thin film 2 instead of the SiO ₂ thin film, and an electroplating layer 4a was formed on the electroless plating layer 4 to form a conductive pattern 5. Similarly, an electromagnetic wave shielding light transmitting window material shown in FIG. 2 was prepared.

That is, in the production of the ITO thin film, as in Example 1, using an electron beam vapor deposition apparatus (EGL-35M; manufactured by ULVAC, Inc.), vapor deposition was performed under the condition of 5 × 10 ⁻⁶ torr, and the average film An ITO thin film having a thickness of 0.5 μm was obtained. The total light transmittance of this ITO thin film was 85% or more.

  In the production of the conductive pattern 5, first, it is immersed in an electroless copper plating bath similar to that in Example 1, and electroless copper plating is performed at 60 ° C. for 80 minutes to form an electroless plating layer 4 having a thickness of 1 μm. did. Next, copper was deposited by an electrolytic plating method to form an electrolytic plating layer 4a having a thickness of 3 μm. As a result, a conductive pattern 5 having a thickness of 4 μm composed of the electroless plating layer 4 having a thickness of 1 μm and the electrolytic plating layer 4a having a thickness of 3 μm was obtained.

  As a result of performing the same measurement as in Example 1, Example 2 also had an aperture ratio of 80%, a reflectance of 10%, and a surface resistance of 0.5Ω / □, as in Example 1.

It is typical sectional drawing which shows the manufacturing method of the electromagnetic wave shielding light transmission window material which concerns on embodiment. It is typical sectional drawing which shows the manufacturing method of the electromagnetic wave shielding light transmission window material which concerns on different embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Metal oxide thin film 3 Print pattern 4 Electroless plating layer 4a Plating layer 5 Conductive pattern 6 Anti-glare layer

Claims (8)

A method for producing an electromagnetic wave shielding light-transmitting window material comprising a transparent substrate and a conductive pattern formed by electroless plating on the surface of the transparent substrate,
Printing an ink containing an electroless plating catalyst on the surface of the transparent substrate to form a printed pattern;
Then, in the method of manufacturing an electromagnetic wave shielding light transmissive window material comprising the electroless plating treatment, and a step of depositing a conductive material on the printed pattern to form the conductive pattern,
A method for producing an electromagnetic wave shielding light-transmitting window material, wherein the ink is printed by an ink jet method.   2. The electromagnetic wave shielding light transmission window according to claim 1, wherein a metal oxide thin film or a metal thin film is formed on the surface of the transparent substrate, and the ink is printed on the metal oxide thin film or the metal thin film. A method of manufacturing the material.   3. The method for producing an electromagnetic wave shielding light transmissive window material according to claim 2, wherein the metal oxide thin film or the metal thin film is formed after the surface of the transparent substrate is subjected to a surface treatment by a corona method or plasma discharge.   4. The method for producing an electromagnetic wave shielding light transmitting window material according to claim 2, wherein the metal oxide thin film or the metal thin film has conductivity.   5. The method of manufacturing an electromagnetic wave shielding light-transmitting window material according to claim 1, further comprising an electrolytic plating treatment on the conductive pattern.   6. The method for manufacturing an electromagnetic wave shielding light-transmitting window material according to claim 1, wherein the printed pattern is formed in a lattice shape.   7. The method for manufacturing an electromagnetic wave shielding light-transmitting window material according to claim 6, wherein the line width of the conductive pattern is 200 [mu] m or less and the aperture ratio is 75% or more.   An electromagnetic wave shielding light-transmitting window material manufactured by the method according to any one of claims 1 to 7.

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