JP2000059080A - Electromagnetic wave shielding adhesive film and electromagnetic wave shielding structure using the film, and display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electromagnetic wave shielding property, transparency and invisibility, and easy adhesion to a bonded body by drawing a geometrical graphic on a plastic film with conductive paste by intaglio offset printing, with the aperture set to a specified value or above, and then forming an adhesive layer on the geometrical graphic. SOLUTION: On a transparent plastic support, a geometrical graphic is drawn with conductive paste by intaglio offset printing, so that the aperture is set to 50% or higher. Then, an adhesive layer is formed on the geometrical graphic. The intaglio offset printing is a method for printing wherein a printing plate is filled in its recessed sections with conductive paste, and then the conductive paste is transferred to a blanket to be printed on a transparent plastic film. As the material for an adhesive layer which constitutes an electromagnetic wave shielding adhesive film, an adhesive composition having a softening temperature of 200 deg.C or below and exhibits fluidity is used. The refractive index of the material is 1.45-1.70. Thereby, an adhesive film having superior electromagnetic wave shielding property, good transparency and invisibility, and superb adhesion to glass or the like can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding adhesive film having a shielding property for electromagnetic waves generated from the front surface of a display such as a CRT, PDP (plasma), liquid crystal, and EL, and an electromagnetic wave shielding using the electromagnetic wave shielding adhesive film. Related to a structure and a display.

[0002]

2. Description of the Related Art As a method of shielding electromagnetic wave noise generated from the front of a display such as a CRT or PDP, a method of forming a thin film conductive layer by depositing a metal or a metal oxide on a transparent substrate (Japanese Patent Laid-Open No. 1-278800). JP-A-5-323101). On the other hand, electromagnetic wave shielding materials in which good conductive fibers are embedded in a transparent base material (Japanese Patent Application Laid-Open Nos. 5-327274 and 5-26)
No. 9912) and an electromagnetic wave shielding material (see JP-A-62-57297 and JP-A-2-52499) in which a conductive resin containing metal powder or the like is directly printed on a transparent substrate. An electromagnetic wave shielding material in which a transparent resin layer is formed on a transparent substrate described above and a copper mesh pattern is formed thereon by electroless plating (see JP-A-5-283889) has been proposed.

[0003]

As a method for achieving both the electromagnetic wave shielding property and the transparency, Japanese Patent Application Laid-Open No. 1-278800 has been disclosed.
In the method of forming a thin film conductive layer by depositing a metal or metal oxide on a transparent substrate disclosed in Japanese Patent Application Laid-Open No. (100 ° to 2,000 °), the surface resistance of the conductive layer becomes too large, and the shielding effect of 30 dB or more, preferably 50 dB or more required at 30 MHz to 1 GHz, is insufficient at 20 dB or less. An electromagnetic wave shielding material in which a good conductive fiber is embedded in a transparent substrate (JP-A-5-327274, JP-A-5-269912)
In the publication, the electromagnetic wave shielding effect of 30 MHz to 1 GHz is 40 to 50 dB, but when the fiber diameter having no problem in visibility is 25 μm, the pitch required for regularly arranging the conductive fibers becomes 50 μm or less, The aperture ratio was reduced and the transparency was impaired, which was not suitable for display applications. Similarly, in the case of an electromagnetic wave shielding material in which a conductive resin containing a metal powder or the like disclosed in JP-A-62-57297 and JP-A-2-52499 is printed directly on a transparent substrate by a screen printing method or the like, the same applies. The line width was about 50 to 100 μm due to the limit of accuracy, and it was not suitable as a front filter because the transparency was reduced and the visibility of lines was exhibited. Further, in a shield material in which a transparent resin layer is formed on a transparent substrate such as polycarbonate described in JP-A-5-283889, and a copper mesh pattern is formed thereon by an electroless plating method, the adhesion of the electroless plating Therefore, there is a limitation that a step of roughening the surface of the transparent substrate is required in order to ensure the above, and that the substrate must not be damaged in the electroless plating step. Further, when the transparent substrate is thick, it cannot be brought into close contact with the display, and there has been a problem that leakage of electromagnetic waves from the transparent substrate increases. In addition, even if electromagnetic wave shielding and transparency could be achieved by this method, on the manufacturing side, the shielding material cannot be made into a scroll like an electromagnetic wave shielding tape, so that it becomes bulky and is not suitable for automation. As a result, there is a disadvantage that the manufacturing cost is increased.

[0004] With respect to the shielding property of electromagnetic waves generated from the front of the display, it is considered that the shielding property at 30 MHz to 1 GHz is 3
In addition to the electromagnetic wave shielding function of 0 dB or more, preferably 50 dB or more, the non-visual property is not only a good visible light transmittance and a large visible light transmittance but also a property that the presence of the shielding material cannot be confirmed with the naked eye. Sex is also required.
Until now, no satisfactory adhesive film has been obtained which has electromagnetic wave shielding properties, transparency, invisibility, and simple adhesiveness to an adherend. In view of the above, the present invention has an electromagnetic wave shielding adhesive film having electromagnetic wave shielding properties, transparency and invisibility, and a simple adhesive property to an adherend, and an electromagnetic wave shielding structure using the electromagnetic wave shielding adhesive film, It is an object to provide a display.

[0005]

Means for Solving the Problems The present inventors have drawn a geometric figure on a plastic film by an intaglio offset printing method using a conductive paste, provided an adhesive layer thereon, and drawn the geometric figure on the plastic film. Geometric figure aperture ratio is 5
It has been found that the above problem can be solved by using an electromagnetic wave shielding adhesive film having a content of 0% or more. The invention according to claim 1 of the present invention is intended to provide an inexpensive electromagnetic wave shielding adhesive film having electromagnetic wave shielding properties, transparency and invisibility, and adhesion to an adherend. An electromagnetic wave shielding adhesive film in which a geometric figure is formed by an intaglio offset printing method using a conductive paste so that the aperture ratio becomes 50% or more, and an adhesive layer is formed thereon. According to a second aspect of the present invention, in addition to the first aspect, in order to provide an electromagnetic shielding adhesive film having excellent electromagnetic shielding properties, metal plating is performed on the conductive paste.
According to the third aspect of the present invention, in order to provide an inexpensive electromagnetic wave shielding adhesive film having excellent contrast, the conductive paste is a black paste. The invention according to claim 4 of the present invention is to blacken the metal plating on the conductive paste in order to provide an electromagnetic wave shielding adhesive film having excellent electromagnetic wave shielding properties and contrast.

According to a fifth aspect of the present invention, a softening temperature of an adhesive layer is set to 200 ° C. or lower in order to provide an electromagnetic wave shielding adhesive film having electromagnetic wave shielding property, transparency and adhesiveness. is there. The invention according to claim 6 of the present invention provides an electromagnetic wave shielding adhesive film having an electromagnetic wave shielding property and excellent transparency and adhesiveness, so that the adhesive layer has a refractive index of 1.45 to 1.70. Is what you do. The invention according to claim 7 of the present invention is to provide an electromagnetic wave shielding adhesive film having an electromagnetic wave shielding property, transparency and excellent adhesiveness, so that the thickness of the adhesive layer is determined by using a conductive paste or a conductive paste. The thickness should be equal to or greater than the thickness of the metal plated thereon. According to an eighth aspect of the present invention, in order to provide an electromagnetic shielding adhesive film having an excellent electromagnetic shielding property, a conductive paste which is cured by ultraviolet light (UV) or heat is intaglio offset on a transparent plastic support. It is formed by a printing method. According to the ninth aspect of the present invention, in order to provide an electromagnetic wave shielding adhesive film having excellent electromagnetic wave shielding properties and transparency, a line width of a geometric figure drawn with a conductive paste is 40 μm or less, 1 interval
The line thickness is not less than 00 μm and the line thickness is not more than 40 μm.

According to a tenth aspect of the present invention, in order to provide an electromagnetic wave shielding adhesive film having excellent electromagnetic wave shielding properties, the conductive filler forming the conductive paste is made of silver, copper, nickel or any of them. Or an alloy containing According to an eleventh aspect of the present invention, there is provided an electromagnetic wave shield for improving adhesion between a transparent plastic support and an adhesive layer or improving adhesion between a transparent plastic support and other members. In order to provide a transparent adhesive film, the transparent plastic support is a surface-treated transparent plastic support. The invention according to claim 12 of the present invention provides an electromagnetic wave shielding adhesive film having excellent adhesiveness,
The method for treating the surface of the transparent plastic support uses at least one of a primer treatment, a plasma treatment and a corona discharge treatment. According to the invention of claim 13 of the present invention, the transparent plastic support is made of a polyethylene terephthalate film or a polycarbonate film in order to provide an inexpensive electromagnetic wave shielding adhesive film having excellent workability. The invention according to claim 14 of the present invention provides an electromagnetic wave shielding structure composed of the above-mentioned electromagnetic wave shielding adhesive film and a transparent plate in order to provide an electromagnetic wave shielding structure having electromagnetic wave shielding properties and transparency. It is. The invention according to claim 15 of the present invention uses any one of the above-mentioned electromagnetic wave shielding adhesive films having electromagnetic wave shielding properties and transparency for a display. Alternatively, the electromagnetic wave shielding structure according to claim 14 is used for a display.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the conductive filler used for expressing the conductivity of the conductive paste of the present invention, metal, metal oxide, amorphous carbon powder, graphite, and metal-plated filler can be used. Metals include copper, aluminum,
Nickel, iron, gold, silver, platinum, tungsten, chromium,
Titanium, tin, lead, palladium and the like, stainless steel containing one or a combination of two or more thereof,
Alloys such as solder can also be used. Silver, copper, nickel, or an alloy containing one or a combination of two or more thereof is suitable from the viewpoints of conductivity, printability, and price. On the other hand, as a metal forming the conductive paste,
When iron, nickel, and cobalt, which are paramagnetic metals, are used, in addition to an electric field, it is possible to improve the shielding property of a magnetic field in particular. The shape of these metals and the like may be any of scaly, resinous, spherical, and irregular shapes, and can be treated with a lubricant or the like. The preferred particle size is 50 μm or less, and if the particle size is larger than this, the conductivity may be reduced. The proportion of the metal in the conductive paste can be arbitrarily adjusted. However, in order to exhibit good shielding properties, it is necessary to mix 30% by weight or more, and more preferably 50% by weight or more. preferable.

[0009] Examples of the binder polymer of the conductive paste include the following. Natural rubber, polyisoprene, poly-1,2-butadiene, polyisobutene,
(Di) enes such as polybutene, poly-2-heptyl-1,3-butadiene, poly-2-t-butyl-1,3-butadiene, poly-1,3-butadiene, polyoxyethylene, polyoxypropylene , Polyvinyl ethyl ether, polyvinyl hexyl ether, polyethers such as polyvinyl butyl ether, polyvinyl acetate, polyesters such as polyvinyl propionate,
Polyurethane, ethylcellulose, polyvinyl chloride, polyacrylonitrile, polymethacrylonitrile, polysulfone, polysulfide, polyethyl acrylate, polybutyl acrylate, poly-2-ethylhexyl acrylate, poly-t-butyl acrylate, poly-3-
Ethoxypropyl acrylate, polyoxycarbonyl tetramethacrylate, polymethyl acrylate, polyisopropyl methacrylate, polydodecyl methacrylate, polytetradecyl methacrylate, poly-n-propyl methacrylate, poly-3,3,5-trimethylcyclohexyl methacrylate, polyethyl methacrylate, Poly (meth) acrylates such as poly-2-nitro-2-methylpropyl methacrylate, poly-1,1-diethylpropyl methacrylate, and polymethyl methacrylate can be used.

[0010] Further, as monomers copolymerizable with acrylic resin and other than acrylic, epoxy acrylate,
Urethane acrylate, polyether acrylate, polyester acrylate and the like can also be used. Particularly, urethane acrylate, epoxy acrylate, and polyether acrylate are excellent from the viewpoint of adhesion to the support. Examples of epoxy acrylate include 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and allyl alcohol diacrylate. Glycidyl ether, resorcinol diglycidyl ether, diglycidyl adipic ester, diglycidyl phthalate, polyethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether,
(Meth) acrylic acid adducts such as glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether and sorbitol tetraglycidyl ether. A polymer, such as epoxy acrylate, having a hydroxyl group after the reaction or in the molecule in the molecule is effective for improving the adhesion to the support. In addition to these, phenol resins, melamine resins, epoxy resins, xylene resins, and the like are applicable. These polymers may be copolymerized as needed, or two or more kinds may be blended. It is also possible to use.

These binder polymers can be used by dissolving them in a general-purpose solvent or by stirring and mixing with a metal together with a metal dispersant or the like without using any solvent. The composition used in the present invention, if necessary, in addition to the dispersant, a thixotropic agent, an antifoaming agent, a leveling agent, a diluent, a plasticizer, an antioxidant, a metal deactivator,
Additives such as coupling agents and fillers may be blended.

On the other hand, the material of the adhesive layer constituting the electromagnetic wave shielding adhesive film is preferably an adhesive composition which is softened by heating at 200 ° C. or lower and exhibits fluidity. The softening point referred to here is a temperature at which the viscosity becomes 10 ¹² P (poise) or less.
Flow was observed within about 10 seconds, and DSC
(Scanning differential calorimeter) or the like can be used to detect the temperature. The following thermoplastic resins are mainly exemplified. For example, natural rubber (n: refractive index, n = 1.52), polyisoprene (n = 1.521), poly-
1,2-butadiene (n = 1.50), polyisobutene (n =
1.505 to 1.51), polybutene (n = 1.513), poly-2-
Heptyl-1,3-butadiene (n = 1.50), poly-2
(Di) enes such as -t-butyl-1,3-butadiene (n = 1.506), poly-1,3-butadiene (n = 1.515), polyoxyethylene (n = 1.456), polyoxypropylene (n = 1.450), polyvinyl ethyl ether (n =
1.454), polyvinylhexyl ether (n = 1.459),
Polyethers such as polyvinyl butyl ether (n = 1.456), polyesters such as polyvinyl acetate (n = 1.467), polyvinyl propionate (n = 1.4665), polyvinyl butyral resin (n = 1.52), polyurethane (n = 1.5 to 1.6) and polyester polyurethane (n = 1.
5-1.6), ethyl cellulose (n = 1.479), polyvinyl chloride (n = 1.54-1.55), polyacrylonitrile (n = 1.
52), polymethacrylonitrile (n = 1.52), polysulfone (n = 1.633), polysulfide (n = 1.6), phenoxy resin (n = 1.5-1.6), polyethyl acrylate (n = 1.469), polybutyl acrylate ( n = 1.466),
Poly-2-ethylhexyl acrylate (n = 1.463),
Poly-t-butyl acrylate (n = 1.464), poly-3
Ethoxypropyl acrylate (n = 1.465), polyoxycarbonyltetramethacrylate (n = 1.465), polymethyl acrylate (n = 1.472 to 1.480), polyisopropyl methacrylate (n = 1.473), polydodecyl methacrylate (n = 1.474), Polytetradecyl methacrylate (n = 1.475), poly-n-propyl methacrylate (n = 1.484), poly-3,3,5-trimethylcyclohexyl methacrylate (n = 1.484), polyethyl methacrylate (n = 1.485), poly- 2-nitro-2-methylpropyl methacrylate (n = 1.487), poly-1,1
Poly (meth) such as diethylpropyl methacrylate (n = 1.489), polymethyl methacrylate (n = 1.489)
Acrylic esters can be used. If necessary, two or more of these acrylic polymers may be copolymerized, or two or more of them may be used as a blend.

Further, epoxy acrylate (n = 1.48 to 1.6) is used as a copolymer resin of acrylic resin and other than acrylic resin.
0), urethane acrylate (n = 1.5 to 1.6), polyether acrylate (n = 1.48 to 1.49), polyester acrylate (n = 1.48 to 1.54) and the like can also be used. In particular, urethane acrylate, epoxy acrylate, and polyether acrylate are excellent from the viewpoint of adhesiveness. Examples of epoxy acrylate include 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl alcohol diglycidyl ether, and resorcinol. (Meth) acrylic such as diglycidyl ether, diglycidyl adipate, diglycidyl phthalate, polyethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol tetraglycidyl ether Acid adducts. Polymers having a hydroxyl group in the molecule, such as epoxy acrylate, which reacts or is originally in the molecule are effective for improving the adhesiveness. These copolymer resins can be used in combination of two or more as necessary. The softening temperature of the polymer serving as the adhesive is preferably 200 ° C. or less, more preferably 150 ° C. or less, from the viewpoint of handleability. On the other hand, it is preferable to use a polymer having a weight average molecular weight of 500 or more. If the molecular weight is 500 or less, the cohesive force of the adhesive composition is too low, and the adhesion to the adherend is reduced.

It is preferable to use an adhesive layer having a refractive index of 1.45 to 1.70 used in the present invention. This is because the visible light transmittance is reduced when the refractive index of the transparent plastic support and the adhesive layer used in the present invention are different, and when the refractive index is 1.45 to 1.70, the visible light transmittance is reduced. The refractive index of the above-mentioned polymer is small and good, and falls within this range. The composition of the adhesive layer used in the present invention, if necessary, a dispersant, a thixotropic agent, an antifoaming agent, a leveling agent, a diluent, a plasticizer, an antioxidant, a metal deactivator, Additives such as coupling agents and fillers may be blended.

As a method of blackening the conductive paste, there is a method of adding a black pigment to a binder polymer of a conductive polymer or using a black additive such as carbon black. When carbon black is used as the black additive, the conductivity of the conductive paste is increased, which is preferable. These black additives are typically binder polymer 100
Contrast can be improved by adding 0.001 part by weight or more to the part by weight, but addition of 0.01 part by weight or more is more preferable. The intaglio offset printing method is suitable as a printing method used when drawing a geometric figure in the present invention. This is because it is excellent in high-precision printability of 50 μm or less as compared with a normal screen printing method or a planographic offset printing method. The intaglio offset printing method is a method in which a conductive paste is filled in a concave portion of a plate, temporarily transferred to a blanket, and then printed on a transparent plastic support.

The geometric figures drawn with the conductive paste by the intaglio offset printing method of the present invention include triangles such as equilateral triangles, isosceles triangles, right triangles, squares, rectangles, and the like.
Rectangles such as rhombus, parallelogram, trapezoid, etc., (positive) hexagons, (positive) octagons, (positive) dodecagons, (positive) n-gons such as (positive) octagons, circles, ellipses, stars The pattern is a combination of molds and the like, and these units can be used alone or in combination of two or more. A triangle is most effective from the viewpoint of electromagnetic wave shielding, but from the viewpoint of visible light transmission, if the line width is the same (positive)
Although the aperture ratio increases as the number n of the n-sided polygon increases, the aperture ratio is required to be 50% or more, and more preferably 60% or more from the viewpoint of visible light transmission. The aperture ratio is a percentage of the ratio of the area obtained by subtracting the area of the conductive paste of the geometric figure drawn with the conductive paste from the effective area to the effective area of the electromagnetic wave shielding adhesive film. When the area of the display screen is defined as the effective area of the electromagnetic wave shielding adhesive film, the display screen is a visible ratio.

The line width of such a geometric figure is 40 μm.
m or less, line spacing is 100 μm or more, line thickness is 4
It is preferable that the thickness be in the range of 0 μm or less. Further, from the viewpoint of invisibility of the geometric figure, the line width is more preferably 25 μm or less, and the line interval is more preferably 120 μm or more and the line thickness is 18 μm or less from the viewpoint of visible light transmittance. The larger the line interval, the higher the aperture ratio and the higher the visible light transmittance, but the lower the electromagnetic wave shielding property. Therefore, the line width is preferably 1 mm or less. When the line interval is complicated by a combination of geometric figures and the like, the area is converted into a square area on the basis of a repeating unit, and the length of one side is set as the line interval.

By applying metal plating on the conductive paste used in the present invention, the electromagnetic wave shielding properties can be further improved. Either electrolytic plating or electroless plating can be used as a method for applying metal plating. The type of plating metal can be gold, silver, copper, nickel, aluminum, etc., but copper or nickel is most suitable in terms of conductivity and price. The range of the plating thickness is preferably from 0.1 to 100 μm, and if it is less than 0.1 μm, the conductivity is insufficient, so that sufficient shielding properties may not be exhibited. If the plating thickness exceeds 100 μm, the viewing angle becomes narrow, which is not preferable. 0.5-50
μm is more preferred. The blackening treatment of metal plating is preferable because the contrast is increased. Further, it is possible to prevent oxidization and fading with time. The blackening treatment is preferably performed after the formation of the metal plating, and can be performed using a method used in the field of printed wiring boards. For example, when the metal plating is copper, sodium chlorite (31 g /
1), an aqueous solution of sodium hydroxide (15 g / l) and trisodium phosphate (12 g / l) at 95 ° C. for 2 minutes.

In order to improve the printability of the conductive paste, various surface treatments can be applied to the transparent plastic support. As the method, treatment by applying a primer, plasma treatment, corona discharge treatment and the like are effective. It is necessary that the critical surface tension of the plastic support after the treatment is 35 dyn / cm or more by these treatments.
0 dyn / cm or more is more preferable. Critical surface tension is 35dy
If it is less than n / cm, the printability of the conductive paste decreases,
When forming a line width of 40 μm or less, there is a possibility that ink spreading or bleeding may occur.

Examples of the transparent plastic support used in the present invention include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene, polypropylene, polystyrene and EVA, polyvinyl chloride and polyvinylidene chloride. Vinyl resin, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide,
It is preferable that the film is made of a plastic such as an acrylic resin and has a total visible light transmittance of 70% or more including colorless or colored and a thickness of 1 mm or less. These can be used as a single layer, or may be used as a multilayer film in which two or more layers are combined. Of these, transparency, heat resistance,
A polyethylene terephthalate film or a polycarbonate film is preferred in terms of ease of handling and price. The thickness of the plastic film is more preferably from 5 to 500 μm. If it is less than 5 μm, the handleability becomes poor,
If it exceeds 500 μm, the transmittance of visible light decreases.
10 to 200 μm is more preferred. On at least one side of the plastic film, vacuum evaporation, sputtering, C
Gold, VD method, spray method, print printing method, etc.
Including silver, copper, aluminum, nickel, iron, cobalt, chromium, tin, titanium, and alloys thereof, or indium oxide, tin oxide, and mixtures thereof (hereinafter, ITO), titanium oxide, stannic oxide, and cadmium oxide Or a mixture thereof may be used to form a conductive thin film layer. Further, an antireflection layer, a near-infrared shielding layer may be formed, or included on the outermost layer of the electromagnetic wave shielding adhesive film or the transparent plastic support. Also, an adhesive layer may be provided at an arbitrary position, an electromagnetic wave shielding adhesive film may be attached thereto, or laminated with another layer.

The transparent plate used in the electromagnetic wave shielding structure of the present invention is a plate made of glass or plastic, and specifically, a polystyrene resin, an acrylic resin, a polymethyl methacrylate resin, a polycarbonate resin, a polyvinyl chloride resin, Thermoplastic polyester resins such as polyvinylidene chloride resin, polyethylene resin, polypropylene resin, polyamide resin, polyamide imide resin, polyether imide resin, polyether ether ketone resin, polyarylate resin, polyacetal resin, polybutylene terephthalate resin and polyethylene terephthalate resin Thermoplastic and thermosetting resins such as cellulose acetate resin, fluororesin, polysulfone resin, polyethersulfone resin, polymethylpentene resin, polyurethane resin, diallyl phthalate resin Fat is being cited. Among these, polystyrene resin having excellent transparency, acrylic resin, polymethyl methacrylate resin, polycarbonate resin,
Polyvinyl chloride resin is preferably used. The thickness of the glass plate or the plastic plate used in the present invention is 0.5 mm to
5 mm is preferable from the viewpoint of protection, strength, and handleability of the display.

[0022]

EXAMPLES Next, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. (Example 1) Polyethylene terephthalate (PET) film having a thickness of 50 µm (manufactured by Toyobo Co., Ltd., trade name A)
-4100), a primer (trade name, manufactured by Hitachi Chemical Co., Ltd., HP-1, coating thickness: 1 μm) is applied to the surface thereof, and silver paste (trade name, manufactured by Hitachi Chemical Co., Ltd.) is applied by intaglio offset printing. , Epimar EM-450
0) was formed (line width 25 μm, line interval (pitch) 250 μm, paste thickness 2 μm). Thereafter, the conductive paste resin is heated and cured at 150 ° C. for 3 hours, and then, as an adhesive layer on the paste, a polyvinyl butyral resin (trade name, # 6000EP, manufactured by Denki Kagaku Kogyo Co., Ltd., softening point 72 ° C., molecular weight 2,400, Refractive index n = 1.5
2) was applied so as to have a dry coating thickness of 20 μm, thereby producing an electromagnetic wave shielding adhesive film. The opening ratio of this film was 81%.

Example 2 A polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., trade name: A-4100) having a thickness of 25 μm was used, and a primer (trade name: HP-trade name, manufactured by Hitachi Chemical Co., Ltd .; 1, coating thickness
1 μm) and a silver paste (trade name, manufactured by Hitachi Chemical Co., Ltd., Epimar EM) containing 0.5% by weight of a black pigment (trade name, Kayaset BlackG, manufactured by Nippon Kayaku Co., Ltd.) using an intaglio offset printing method -4500) grid pattern (line width 20 μm, line interval (pitch) 286 μm)
m, paste thickness 3 μm). Then 160
The paste resin was cured by heating at 2 ° C. for 2 hours. A copper plating layer having a thickness of 3 μm is formed on the resulting grid pattern of the silver paste by electrolytic copper plating in a conventional manner, and a polyvinyl butyral resin (trade name, manufactured by Sekisui Chemical Co., Ltd., BL-1, softening point 105 ° C, molecular weight 1.9
, N = 1.52) was applied to a dry coating thickness of 30 μm to produce an electromagnetic wave shielding adhesive film (electrolytic copper plating: for example, Handbook of Printed Circuit Technology, edited by Japan Printed Circuit Industry Association, Nikkan) Kogyo Shimbun, February 28, 1987, page 470). The aperture ratio of this film is 86%
Met.

Example 3 A polycarbonate film (Lexan, trade name, manufactured by Asahi Glass Co., Ltd.) having a thickness of 25 μm was used, and its corona-treated surface (critical surface tension: 54 dyn / cm) was subjected to the following exposure using intaglio offset printing. Grid pattern of conductive nickel paste containing nickel particles in conductive resin (line width 30 μm, line interval (pitch) 12
7 μm, and a paste thickness of 2.5 μm). Thereafter, ultraviolet rays of 1 J / cm ² are irradiated using an ultraviolet lamp, and the paste resin is further heated and cured at 120 ° C. for 60 minutes. As an adhesive layer on the paste resin, a polyester polyurethane resin (a product of Toyobo Co., Ltd.) Name, Byron
(UR-1400, softening point: 83 ° C., average molecular weight: 40,000, n = 1.5) so as to have a dry coating thickness of 25 μm to prepare an electromagnetic wave shielding adhesive film. The aperture ratio of this film is 5
8%. (Composition of photosensitive resin) 2,2-Bis (4,4'-N-malemiticylphenoxyphenyl) fluorophene 30 parts by weight ethoxy equivalent 500 equivalents of bisphenol A-type epoxy resin and 1 equivalent of tetrahydroquinophthalic anhydride in a nitrogen atmosphere Acid-modified ethoxy resin obtained by reacting at 150 ° C. for 10 hours under the conditions: 45 parts by weight of acrylonitrile phthalocyanine (PNR-1H, trade name of Nippon Synthetic Rubber Co., Ltd.) 20 parts by weight of 1,7-bis (9,9-acrylic acid) ) Heptane 5 parts by weight Aluminum hydroxide 10 parts by weight Nickel particles were dispersed in a 45% by weight varnish of cyclohexanone / methyl ethyl ketone (1/1 weight ratio) so as to be 30% by volume.

Example 4 A 50 μm thick PET film (trade name, A-4100, manufactured by Toyobo Co., Ltd.) was used, and a primer (trade name, HP-1, manufactured by Hitachi Chemical Co., Ltd., HP-1) was applied on the surface. 1 μm), and using an intaglio offset printing method, an epoxy phenol resin containing 0.5% by weight of a black pigment (trade name, Kayaset BlackG, manufactured by Nippon Kayaku Co., Ltd.) as a binder (a product manufactured by Hitachi Chemical Co., Ltd.) Name, TBA-HME and Toto Kasei Co., Ltd. product name,
Lattice pattern (line width 20 μm, line interval (pitch)) 2 of copper paste formed into a blended product of YD-8125
50 μm, and a paste thickness of 2 μm). afterwards,
The paste resin was cured by heating at 150 ° C. for 3 hours. A 1 μm thick copper plating layer is formed on the grid pattern of the completed copper paste by electroless copper plating (trade name, CUST-201, manufactured by Hitachi Chemical Co., Ltd.), and an acrylic layer is further formed thereon as an adhesive layer. Resin (trade name, manufactured by Teikoku Chemical Industry Co., Ltd., HTR-811, softening point -43 ° C, average molecular weight 420,000, n = 1.
52) was applied so as to have a dry coating thickness of 20 μm to prepare an electromagnetic shielding adhesive film. The opening ratio of this film was 84%.

Example 5 A 50 μm-thick PET film (trade name, manufactured by Toyobo Co., Ltd., A-4100) was used, and a primer (trade name, manufactured by Hitachi Chemical Co., Ltd., HP-1, HP-1) was applied to the surface. 1 μm), and a silver paste containing 1% by weight of carbon black (trade name, manufactured by Lion Corporation, Ketjen Black EC-600: average particle size 0.03 μm) using an intaglio offset printing method (Hitachi Chemical Industry Co., Ltd.) Company name, Epimar EM-450
0) was formed (line width 20 μm, line interval (pitch) 250 μm, paste thickness 2 μm). Thereafter, the paste resin was cured by heating at 160 ° C. for 2 hours. A 5 μm thick copper plating layer is formed by electrolytic copper plating on the lattice pattern of the completed silver paste, and a polyvinyl butyral resin (trade name, # 6000EP, manufactured by Denki Kagaku Kogyo Co., Ltd., Softening point 72
C., molecular weight of 2,400, n = 1.52) so as to have a dry coating thickness of 20 μm to produce an electromagnetic shielding adhesive film. The opening ratio of this film was 84%.

Example 6 The adhesive layer surface of the electromagnetic wave shielding adhesive film obtained in Example 1 was coated on a commercially available acrylic plate (commercial glass, Kuraray Co., Ltd., thickness 3 mm).
And the opposite side thereof to a commercially available soda lime glass having a thickness of 3 mm using a hot press through an adhesive film (trade name, manufactured by Sekisui Chemical Co., Ltd., Esrec, 250 μm in thickness) at 110 ° C., 20 kgf / cm ² , It was heated and pressed under the conditions of 15 minutes to obtain an electromagnetic wave shielding structure.

Comparative Example 1 Using the PET film, primer, conductive paste and adhesive used in Example 1,
Instead of the intaglio offset printing method, using a screen printing method, a line width of 25 μm and a line interval (pitch) of 2
Although a grid pattern of 50 μm was formed, many lines were blurred, blurred, and disconnected. The average paste thickness was 10 μm or more.

Comparative Example 2 Using the PET film, primer, conductive paste and adhesive used in Example 1,
Instead of the intaglio offset printing method, a lithographic offset printing method was used to form the same lattice pattern as in Example 1. However, because of bleeding, a line width of 25 μm could not be formed. Minimum printable line width is 5
It was about 0 μm. Similarly, a 25 μm line width could not be formed by the letterpress offset printing method.

Comparative Example 3 Using the PET film, primer, conductive paste and adhesive used in Example 1,
Line width 45 μm, line interval (pitch) 125 μm,
A lattice pattern having a paste thickness of 2 μm was formed. Thereafter, in the same manner as in Example 1, the paste resin was heated and cured at 150 ° C. for 3 hours to produce an electromagnetic wave shielding adhesive film. The opening ratio of this film was 40%.

(Comparative Example 4) The PET film of Example 2
A primer layer was formed, and a grid pattern having a line width of 20 μm, a line interval (pitch) of 286 μm, and a paste thickness of 3 μm was formed using a conductive paste. Thereafter, the paste resin was heated and cured at 160 ° C. for 2 hours in the same manner as in Example 2 to produce an electromagnetic wave shielding adhesive film having no adhesive layer. The opening ratio of this film was 86%.

Reference Example 1 The procedure was carried out except that a polyimide film (trade name, Kapton, visible light transmittance 18%, manufactured by Du Pont-Toray Co., Ltd.) having a thickness of 25 μm and having a sandblasted surface was used as a transparent plastic support. Example 1
The electromagnetic wave shielding adhesive film was produced using the primer, the conductive paste and the adhesive used in the above.

Reference Example 2 An electromagnetic wave shielding adhesive film was prepared in the same manner as in Example 2 except that the following composition was used as the adhesive layer and the dry coating thickness was 25 μm. (1) 100 parts by weight of YD-8125 (trade name, manufactured by Toto Kasei Co., Ltd .; bisphenol A type epoxy resin, Mw = 300,000) (2) IPDI (manufactured by Hitachi Chemical Co., Ltd .; 12.5 parts by weight of mask isophorone diisocyanate) (3) 0.3 parts by weight of 2-ethyl-4-methylimidazole (4) 0.4 parts by weight of UFP-HX (infrared absorbent: trade name, manufactured by Sumitomo Metal Mining Co., Ltd .; ITO, average particle size: 0.1 μm) (5) MEK 330 parts by weight (6) Cyclohexanone 15 parts by weight The refractive index of the composition after solvent drying is 1.57, and the softening point is 2
It was 00 ° C or higher.

The electromagnetic wave shielding adhesive film obtained as described above, the conductive paste of the electromagnetic wave shielding structure or the aperture ratio of the geometrical figure drawn by the conductive paste and the metal plating, the presence or absence of abnormality in the printed pattern, Electromagnetic wave shielding properties (300 MHz), visible light transmittance, invisibility, contrast, and adhesion to a glass plate were measured. Table 1 shows the measurement results.

The aperture ratio of the conductive paste or a geometric figure drawn by the conductive paste and the metal plating was actually measured based on a micrograph. The electromagnetic wave shielding property is measured using a coaxial waveguide converter (trade name, TWC-S-02, manufactured by Japan High Frequency Corporation).
The sample was inserted between the flanges of 4), and measured at a frequency of 300 MHz using a spectrum analyzer (trade name, manufactured by YHP, 8510B vector network analyzer). The visible light transmittance was measured using a double beam spectrophotometer (trade name, manufactured by Hitachi, Ltd., Model 200-10), and the average value of the transmittance at 400 to 700 nm was used.
The presence / absence, invisibility and contrast of the printed pattern were determined by visual observation. Regarding the non-visibility, the electromagnetic wave shielding adhesive film was observed from a place 0.5 m away, and those which could not recognize the geometrical figure formed of the conductive material were good, and those which could recognize it were NG. The contrast is
Adhere the electromagnetic shielding adhesive film to the screen of the plasma display device, observe the contrast,
Those with excellent contrast were evaluated as good, and those with poor contrast were evaluated as NG. The adhesion of the electromagnetic wave shielding adhesive film to glass was measured by bonding the film to glass at 110 ° C. and 5 kgf / cm ² using a roll laminator, and measuring the adhesive force.

[0036]

[Table 1]

In Comparative Example 1, an attempt was made to form a grid pattern with a line width of 25 μm and a line interval (pitch) of 250 μm by using a screen printing method, but many lines were blurred, blurred, and disconnected. In Comparative Example 2, pattern formation was attempted using the lithographic offset printing method and the letterpress offset printing method, and the minimum printable line width was 50 μm. Comparative Example 3 has a line width of 45
In this example, a grid pattern having a line spacing (pitch) of 125 μm was used, but the aperture ratio was only 40%. In Comparative Example 4, an electromagnetic wave shielding adhesive film was produced without providing an adhesive layer, but had no adhesiveness to glass. In Reference Example 1, a 25 μm thick polyimide film was used as a transparent plastic support, and the visible light transmittance was 15% or less. Reference example 2
Used an adhesive layer having a softening point of 200 ° C. or higher, but did not realize adhesion to glass as in Comparative Example 4. For these comparative examples, in the structure in which the transparent plastic support, the conductive paste, and the adhesive layer were arranged in this order, as shown in the examples of the present invention,
The conductive paste has a geometric figure drawn by intaglio offset printing, and its electromagnetic wave shielding adhesive film with an aperture ratio of 50% or more is free from line bleeding, blurring, disconnection, and the minimum printable line width is It was as good as 20 μm or less. The electromagnetic wave shielding property is 30 dB or more in spite of the high aperture ratio and high brightness, and the electromagnetic wave shielding property can be made 50 dB or more by applying metal plating to a geometric figure drawn with a conductive paste. In addition, by performing the blackening process, the contrast is improved, and a clear image can be viewed. Furthermore, it exhibits good adhesiveness to an adherend such as glass.

[0038]

Since the electromagnetic wave shielding adhesive film obtained in the present invention is manufactured by using an intaglio offset printing method, it is excellent in electromagnetic wave shielding, transparency, invisibility and adhesion to glass and the like. It is possible to provide the electromagnetic wave shielding adhesive film at low cost. By applying metal plating to the conductive paste according to claim 2, it is possible to provide an electromagnetic wave shielding adhesive film having extremely excellent electromagnetic wave shielding properties. By using the conductive paste according to claim 3 as a black paste, it is possible to provide an inexpensive electromagnetic shielding adhesive film having excellent contrast. By subjecting the metal plating on the conductive paste according to claim 4 to blackening treatment, it is possible to provide an electromagnetic wave shielding adhesive film having excellent contrast. The softening temperature of the adhesive layer according to claim 5 is 20.
When the temperature is 0 ° C. or lower, an electromagnetic wave shielding adhesive film having excellent adhesion to an adherend can be provided.

The refractive index according to claim 6 is 1.45 to 1.
By setting the adhesive layer in the range of 70, it is possible to provide an electromagnetic wave shielding adhesive film having excellent transparency. By setting the thickness of the adhesive layer according to claim 7 to be equal to or greater than the thickness of the conductive paste or the conductive paste and the thickness of metal plating thereon, an electromagnetic wave shielding adhesive film having excellent transparency and adhesiveness can be obtained. Can be provided. In the intaglio offset printing method according to claim 8,
By using a conductive paste that is cured by ultraviolet light (UV) or heat, an inexpensive and highly reliable electromagnetic wave shielding adhesive film can be provided. 10. The geometric figure drawn with the conductive paste according to claim 9 has a line width of 4.
By setting the line thickness to 0 μm or less, the line interval to 100 μm or more, and the line thickness to 40 μm or less, it is possible to provide an electromagnetic wave shielding adhesive film having excellent transparency and electromagnetic wave shielding properties. By providing the conductive filler forming the conductive paste according to claim 10 with silver, copper, nickel or an alloy containing any of them, it is possible to provide an electromagnetic wave shielding adhesive film excellent in transparency and electromagnetic wave shielding properties. be able to. When the transparent plastic support according to the eleventh aspect is a transparent plastic support having a surface treatment, it is possible to obtain an electromagnetic wave shielding adhesive film having excellent electromagnetic wave shielding properties and adhesion reliability. An electromagnetic wave having excellent electromagnetic wave shielding properties and adhesion reliability by using at least one of a primer treatment, a plasma treatment, and a corona discharge treatment as the surface treatment method for a transparent plastic support according to claim 12. The shielding adhesive film can be obtained at low cost. By making the transparent plastic support according to claim 13 a polyethylene terephthalate film or a polycarbonate film, an electromagnetic wave shielding adhesive film having excellent transparency can be provided at low cost.
By providing the electromagnetic wave shielding structure composed of the electromagnetic wave shielding adhesive film according to claim 14 and a transparent plate, it is possible to provide a transparent electromagnetic wave shielding substrate. By using the electromagnetic wave shielding adhesive film having the electromagnetic wave shielding property and transparency according to claim 15 or the electromagnetic wave shielding structure for a display,
It is possible to provide a display that is lightweight, compact, has excellent transparency, and has low electromagnetic wave leakage.

When the electromagnetic wave shielding adhesive film is used for a display, the visible light transmittance is large and the invisibility is good, so that a clear image can be obtained under almost the same conditions as in a normal state without increasing the luminance of the display. Can be comfortably viewed. Moreover, since the film itself has adhesiveness, it can be easily bonded to an adherend. The electromagnetic wave shielding adhesive film and the electromagnetic wave shielding structure of the present invention are excellent in electromagnetic wave shielding properties and transparency,
Measuring equipment that generates or protects against electromagnetic waves in addition to displays, windows and housings that look inside measuring equipment and manufacturing equipment, especially in areas such as windows that require transparency. Can be.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Minoru Tosaka 1500 Oji Ogawa, Shimodate City, Ibaraki Pref.Hitachi Kasei Kogyo Co., Ltd. Inside the Shimodate Research Laboratory of the Company (72) Inventor Akishi Nakaso 48 Wadai, Tsukuba, Ibaraki Prefecture Hitachi Chemical Co., Ltd. GG33 HH02 HH12 KK07

Claims (15)

[Claims] 1. A structure in which a transparent plastic support, a conductive paste, and an adhesive layer are arranged in this order, wherein the conductive paste has a geometrical pattern drawn by intaglio offset printing, and an aperture ratio thereof. Is 50% or more. 2. The electromagnetic wave shielding adhesive film according to claim 1, wherein metal plating is applied on the conductive paste. 3. The electromagnetic wave shielding adhesive film according to claim 1, wherein the conductive paste is a black paste. 4. The method according to claim 2, wherein the metal plating on the conductive paste is blackened.
The electromagnetic wave shielding adhesive film according to 1. 5. The electromagnetic wave shielding adhesive film according to claim 1, wherein the adhesive layer has a softening temperature of 200 ° C. or lower. 6. The adhesive film according to claim 1, wherein the adhesive layer has a refractive index in the range of 1.45 to 1.70. 7. The method according to claim 1, wherein the thickness of the adhesive layer is not less than the thickness of the conductive paste or the conductive paste and the metal plated thereon. Electromagnetic wave shielding adhesive film. 8. The electromagnetic wave shielding adhesive film according to claim 1, wherein a conductive paste that is cured by ultraviolet light (UV) or heat is used. 9. The electromagnetic wave according to claim 1, wherein a line width of the geometrical figure drawn by the conductive paste is 40 μm or less, a line interval is 100 μm or more, and a line thickness is 40 μm or less. Shielding adhesive film. 10. The electromagnetic wave shielding adhesive film according to claim 1, wherein the conductive filler forming the conductive paste is silver, copper, nickel, or an alloy containing any of them. 11. The plastic support according to claim 1, wherein the transparent plastic support is a surface-treated plastic support.
0. The electromagnetic wave shielding adhesive film according to any of 1. 12. The electromagnetic wave shielding property according to claim 1, wherein the surface treatment of the transparent plastic support uses at least one of primer coating, plasma treatment and corona discharge treatment. Adhesive film. 13. The electromagnetic wave shielding adhesive film according to claim 1, wherein the transparent plastic support is a polyethylene terephthalate film or a polycarbonate film. 14. An electromagnetic wave shielding structure comprising the electromagnetic wave shielding adhesive film according to claim 1 and a transparent plate. 15. The electromagnetic wave shielding adhesive film according to any one of claims 1 to 13, or claim 1.
A display using the electromagnetic wave shielding component according to 4.