JP2009026942A - Electromagnetic wave shield material improved in transparency decrease and using printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve transparency by preventing a decrease in transparency such as a haze increase due to an uneven shape imparted from a plate surface etc., to a primary layer surface when a conductive ink print layer is printed by using a novel intaglio printing method of transferring conductive ink to a transparent base material via a primer layer hardened on a plate, in an electromagnetic wave shield material. <P>SOLUTION: The electromagnetic wave shield material 10 is improved in transparency by coating an uneven shape 15 on the surface of the primer layer 12 on the transparent material 11 with a transparency layer 16 to make the surface smooth. To make the uneven shape optically transparent, a relation of ¾np-nt¾<¾np-na¾ is preferable and ¾np-nt¾≤0.14 is more preferable, where np is a primer layer refractive index, nt is a transparency layer refractive index, and na is an air refractive index. The transparency layer can serve also as a flattening layer. The thickness of the primer layer right below the conductive ink print layer 13 is larger than that at an opening portion 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is particularly suitable for being arranged on the front surface of a display (image display device), and a predetermined conductive pattern represented by a mesh shape is formed by using a printing method, and transparency due to the printing method is reduced. The present invention relates to an electromagnetic shielding material.

  At present, as an electromagnetic shielding material, there is a photolithographic method in which a metal foil is etched to form a mesh pattern. From the viewpoint of cost, waste liquid treatment, etc., for example, the following (1) to (3), Various proposals using printing methods have also been made.

(1) Screen printing of electroless plating catalyst ink on a transparent substrate to form a mesh pattern catalyst ink printing layer, followed by electroless plating and forming a mesh pattern metal plating layer on the catalyst ink printing layer An electromagnetic shielding material that uses a screen printing method for the formed plating catalyst ink (Patent Document 1).
(2) Conductive ink containing conductive powder is printed on a transparent substrate by intaglio offset printing to form a mesh pattern conductive ink printing layer, followed by electrolytic plating, and mesh pattern metal plating on the conductive ink printing layer. The electromagnetic wave shielding material which uses the intaglio offset printing method for the conductive ink which formed the layer (patent document 2).
(3) An electroless plating catalyst ink in which gold fine particles are dispersed in an ultraviolet curable resin is filled in a mesh-shaped concave portion of an intaglio plate, and an ultraviolet ray is irradiated on the plate while the transparent base material is pressed onto the intaglio plate. After intaglio printing on a transparent substrate in a form to make the plate a shaping mold, a mesh pattern catalyst ink printing layer is formed, and then electroless plating is performed on the catalyst ink printing layer. An electromagnetic wave shielding material using a special intaglio printing method for the plating catalyst ink having a plating layer (Patent Document 3).

JP 11-170420 A JP 2001-102792 A Japanese Patent Laid-Open No. 11-174174

  However, it is particularly suitable for display applications. For example, in the case of a thin line pattern having a line width of about 5 to 30 μm that is difficult to visually distinguish, any electromagnetic shielding material using the printing methods (1) to (3) above. However, printing defects such as jagged lines (non-smooth broken lines and zigzags) and disconnection are likely to occur in the thin lines, which is not satisfactory.

The reason is that in the screen printing method (1), the ink viscosity is high, and the fine lines defining the screen are transferred, so that there is a performance limit for the fine line.
In addition, in the intaglio offset printing method of (2) above, the ink is not directly transferred, but is transferred indirectly from the intaglio to the transparent substrate via the offset rubber blanket roller, and the ink is transferred from above the blanket roller. The pattern on the intaglio cannot be faithfully reproduced on the transparent substrate because it is spread and distorted by the printing pressure.

Moreover, a problem inherent to intaglio printing is a low transfer rate. There are two reasons for this, and the first reason is that the volume of liquid ink in the recesses that is transferred to the substrate side of the total volume of ink that fills the recesses due to the effects of viscosity, surface tension, etc. is limited. (The rest remains in the recess). In particular, in the case of ink containing solid particles at a high concentration, such as conductive ink and gold-plated catalyst ink, the ink in the recesses is difficult to move, so the transfer rate is further reduced as compared with normal ink. The second reason is that in the intaglio plate, the ink to be transferred is filled in the concave portion of the plate surface, so that excess ink on the plate surface convex portion other than the concave portion is removed by scraping with a doctor blade, etc. The upper surface of the ink part filled in the film cannot be completely flush with the convex part of the plate surface, and may have a slightly depressed shape. Then, the contact between the filled ink and the printing material becomes incomplete at the recessed portion, and the transfer of the ink to the printing material is inhibited. As a result, not only the reduction rate (evaluated by the volume (or thickness) of the ink transferred onto the substrate to be printed / the volume of ink in the intaglio recess (or recess depth))), Missing transition (ink missing) such as disconnection occurs. Furthermore, a printing defect such as a decrease in adhesion to the printing material occurs, which causes a decrease in electromagnetic shielding performance.
Even if it is changed to print directly on the substrate from the intaglio without using the offset method, the pattern distortion inherent to offset can be eliminated, but the low transfer rate and pattern omission remain unresolved. Remains.

Further, in the improved intaglio printing method using the plate (3) as a shaping mold, the ink is transferred directly and the ink is solidified in the recesses on the intaglio. That is, first, the shape of the concave portion of the plate is shaped faithfully and then transferred from the plate, so that the ink transfer rate is higher (100% in principle) than the above (1) and (2), and the fine line Excellent pattern reproducibility. However, in reality, the transfer of ink from the intaglio to the transparent substrate was not completely ideal with a fine fine line pattern.
This is because it is inevitable that the top surface of the filling ink is recessed when ink is filled in the concave portion of the intaglio surface. It has not been possible to completely prevent the occurrence of printing defects such as fine lines due to this, lack of dislocations such as jagged lines and disconnection, and deterioration of adhesion to the substrate. Furthermore, as a problem of the above (3), in order to apply such a method, it is necessary to constitute the binder resin of the catalyst ink or the conductive ink with an ultraviolet curable resin. On the other hand, the catalyst ink or conductive ink contains a large amount of ultraviolet light-shielding particles made of gold or graphite, so it is difficult to cure the ink sufficiently in the intaglio depression, and it is designed to be incompletely cured. The ink does not transfer completely. Also, the transferred ink has poor strength and durability.

  Therefore, the present applicant has improved the ink transferability with respect to the intaglio printing methods as described in the above (2) and (3), and is capable of improving printing defects such as insufficient transfer and poor adhesion. The method was proposed in Japanese Patent Application No. 2007-153113 which has not been disclosed at the time of filing the present invention.

As shown in FIG. 7 (a), the novel printing method is a primer layer 32A in a liquid state in which a primer previously applied to a printing material (transparent substrate) 31 before contacting the intaglio 33 is used as a primer layer 32A in a liquid state. After contacting the intaglio plate 33 as shown in FIG. 7B, it is solidified on the plate by ultraviolet irradiation, cooling, etc., and then the substrate 31 is separated from the intaglio plate 33 as shown in FIG. In this printing method, the ink 34 in the recesses is transferred onto the solidified primer layer 32 on the substrate 31. At this time, even if there is a depression 35 on the surface of the ink 34 filled in the recess, the primer layer is liquid, so it flows into the depression and fills the depression, resulting in poor contact between the printed material and the ink at the ink depression. Eliminate. Furthermore, depending on the materials used and printing conditions, the primer and ink are mutually diffused, dissolved or permeated in the vicinity of the interface between the primer layer 32 and the ink 34 to improve the adhesion between the layers. A mechanism for reducing the fluidity of itself is also added. As a result, this is an intaglio printing method in which the transferability of the ink is improved, and the lack of transfer and the decrease in adhesion are improved.
In addition, when transferring the ink, the ink may be cured and solidified on the plate as in (3) (intaglio printing method in which the plate is shaped with respect to the ink), but it remains liquid. It may be transferred (a normal intaglio printing method in which the plate is not shaped with respect to the ink), and in either case, the ink transfer property is improved and the printing defect can be improved.
As described above, since conductive inks and catalyst inks generally have strong ultraviolet shielding properties, usually the ink in the intaglio recesses is not completely solidified and often transfers while remaining somewhat fluid.

  However, since the liquid primer layer is necessarily solidified on the intaglio, the intaglio functions as a shaping type for the primer layer. For this reason, the surface of the primer layer formed and solidified on the substrate during printing of the conductive ink printed layer is faithfully in the same reverse shape even if it is a minute uneven shape on the convex surface of the intaglio plate (the surface where no concave portion is formed). Will be shaped and reproduced. The concavo-convex shape of the convex surface of the plate surface includes minute cracks on the plating surface when the plate surface is chrome-plated for plate durability, scratches on the doctor blade, polishing scratches when the plate surface is polished, etc. Unnecessary and undesired. In addition, dust embraced between the transparent base material and the intaglio at the time of printing also causes the uneven shape formed on the surface of the primer layer.

  By the way, the so-called gravure printing method, which is a kind of intaglio printing method, is a gravure printing plate that uses halftone dots for reproduction of density gradation images such as photographs, and is provided with a plurality of concave portions called cells expressing halftone dots. However, most of the plate surface area in the image area is a dense cell portion, and the area of the plate convex portions (called “bank”) other than the cells existing between the cells is relatively small. Therefore, even if the top surface of the bank is uneven due to scratches or the like, it is not noticeable on the printed matter. However, in a non-image area that is a portion where a photograph or text is not printed, a print defect called “background stain” may occur. The background stain is a phenomenon in which, due to insufficient ink scraping by the doctor blade, an area where no cell is provided on the plate surface corresponds, and unnecessary ink adheres to the originally white portion of the printed surface and becomes dirty.

On the other hand, in the electromagnetic wave shielding material suitable for placing on the front surface of the display, the intaglio corresponding to the line portion of the pattern of the conductive ink printing layer is required in order to ensure light transmission. The concave portion (this portion becomes a light shielding portion in the electromagnetic wave shielding material) is a groove shape and occupies a very small area of the plate surface, and most of the area of the plate surface is a concave portion corresponding to the opening in the electromagnetic wave shielding material. The area relation between the concave part and the convex part on the plate surface is completely opposite to that of the general gravure printing plate for image printing described above. In addition, because of the relationship of ensuring transparency by the light transmittance of the opening at the part corresponding to the plate convex part, the uneven shape on the surface of the primer layer adversely affects the optical performance such as light diffusion and haze reduction, and decreases the transparency. It turned out that it was letting.
In addition, “background stain” in general image printing is a phenomenon in which unnecessary ink adheres and stains, whereas the uneven shape formed on the primer layer is a phenomenon of unnecessary ink such as background stain. This is not a cause of adhesion but a shape factor of unintentional irregularities formed at the time of printing, which is a newly generated defect peculiar to the novel printing method. For this reason, when pursuing transparency, improvement of this defect was desired.

  That is, the object of the present invention is to provide a new intaglio printing method in which ink is transferred to a transparent base material to be printed through a primer layer that is solidified on a plate like the above-described new printing method. When printing conductive ink printing layer in a predetermined pattern, it is improved by preventing the deterioration of transparency due to the uneven shape (unwanted but inevitably generated or uneven shape that is unavoidably generated) on the surface of the solidified primer layer An electromagnetic shielding material is provided.

  Therefore, in the present invention, the following electromagnetic wave shielding material having improved transparency by covering and smoothing the uneven shape on the surface of the primer layer as described above with a transparent layer.

(1) A transparent substrate, a primer layer formed on the transparent substrate, and a conductive ink printing layer formed in a predetermined pattern on the primer layer, and the conductive ink among the primer layers. The electromagnetic wave shielding material having a thickness of the printed layer part larger than the thickness of the opening that is a non-formation part of the conductive ink printing layer, and there is an uneven shape on the surface of the primer layer in the opening, An electromagnetic wave shielding material in which a transparent layer that fills and smoothes the uneven shape covers at least a primer layer in an opening.
In this configuration, the primer layer formed so that the area directly under the conductive ink printing layer is thicker than the opening prevents fine lines due to insufficient ink transfer, disconnection, and poor ink adhesion, resulting in an ink transfer rate. In addition, the uneven shape on the surface of the primer layer in the opening is smoothed by the transparent layer, so the uneven shape becomes inconspicuous, and optical performance degradation such as reduced transparency due to increased haze is suppressed, improving transparency. And improve.

(2) In the above (1), when the refractive index of the primer layer is np, the refractive index of the transparent layer is nt, and the refractive index of air is na, these relationships are | np−nt | <| Np-na | is preferable. Optical performance degradation due to uneven shape due to small difference in refractive index between primer layer and clearing layer when clearing layer is present compared to refractive index difference between primer layer and air when clearing layer is not present Is reliably suppressed, and transparency is improved and improved.
(3) Preferably in the above (2), | np−nt | ≦ 0.14. If the difference in refractive index between the primer layer and the transparent layer is so small, the optical performance deterioration is more reliably suppressed, and the transparency is improved and improved.

(4) In any one of the above (1) to (3), the transparent layer also serves as a flattening layer that reduces and flattens the surface level difference between the opening and the conductive ink print layer portion. .
In this configuration, in the case where an optical filter layer or the like is additionally laminated on the surface of the electromagnetic wave shielding material on the side of the conductive ink printing layer via an adhesive layer or the like, it is possible to improve the inclusion of bubbles due to a step.

(5) An electromagnetic wave shielding material having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive ink printing layer formed in a predetermined pattern on the primer layer, the conductive ink The surface of the primer layer at the opening, which is a non-printing portion of the printing layer, has a concavo-convex shape formed during printing of the conductive ink printing layer, and at least a transparent layer that fills and smoothes the concavo-convex shape is opened. It is an electromagnetic wave shielding material which coats the primer layer in the part.
According to this configuration, the conductive ink printing layer formed by printing via the primer layer solidified on the plate can prevent printing defects such as fine line burrs and disconnection due to insufficient ink transfer, and ink adhesion deterioration. In addition to improving the transition rate, the uneven shape formed on the surface of the primer layer by solidifying on the plate during printing is filled with a transparent layer and smoothed, so the uneven shape becomes inconspicuous and transparent due to increased haze As a result, optical performance degradation, such as deterioration in optical properties, is suppressed, and transparency is improved and improved.

(6) The electromagnetic wave shielding material according to any one of the above (1) to (5), wherein a metal thin film is further formed on the surface of the pattern comprising the conductive ink printing layer.
According to this configuration, the conductivity of the formed conductive ink printing layer can be further improved, and the electromagnetic wave shielding property is further improved.

(1) In the electromagnetic wave shielding material according to the present invention, the primer layer thickened immediately below the conductive ink printing layer prevents printing defects such as fine line knurls and disconnection, insufficient ink transfer, and poor ink adhesion, and improves the ink transfer rate. A high-definition conductive ink printing layer can be realized by the printing method. Moreover, the minute uneven shape on the surface of the primer layer is smoothed by the transparent layer and becomes inconspicuous, and the optical performance such as a decrease in transparency due to an increase in haze is suppressed, thereby improving the transparency. In addition, by improving the ink transfer rate, it is possible to form a thick conductive ink printing layer, and it is easy to improve the electromagnetic shielding performance.
(2) Further, if the refractive index of the transparent layer is optimized with the refractive index of the primer layer or the like, and preferably the difference in refractive index between the transparent layer and the primer layer is 0.14 or less, the uneven shape Can be effectively inconspicuous and the transparency can be improved more reliably.
(3) Furthermore, if the transparent layer is also used as a flattening layer, it is possible to reduce the level difference due to the conductive ink printing layer without using a special flattening layer, and additional layers such as an optical functional layer can be laminated. You can also prevent air bubbles.

(4) Further, in the electromagnetic wave shielding material according to the present invention, the primer layer solidified on the plate can prevent printing defects such as fine line knurls and disconnection, insufficient ink transfer, and poor ink adhesion, and also improve the ink transfer rate. A high-definition conductive ink printing layer can be realized by the printing method. Moreover, as a result, the uneven shape formed on the surface of the primer layer by solidifying the primer layer on the plate at the time of printing is suppressed from causing a decrease in optical performance such as a decrease in transparency due to an increase in haze. Improves and improves. In addition, due to the improvement in the ink transfer rate, the conductive ink printing layer can be formed thick, and the electromagnetic wave shielding performance can be easily improved.

(5) Moreover, the electrical conductivity of a conductive ink printing layer can be improved further by the further metal thin film of the pattern surface of a conductive ink printing layer, and electromagnetic wave shielding property further improves.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

[Explanation of drawings]
FIG. 1 is a cross-sectional view illustrating an electromagnetic wave shielding material according to an embodiment of the present invention, FIG. 2 is a cross-sectional view illustrating the thickness of a primer layer in a conductive ink printing layer portion and an opening, and FIG. 3 is according to the present invention. FIG. 4 is a cross-sectional view illustrating another form of the electromagnetic wave shielding material (entire surface of the transparent layer), FIG. 4 is a cross-sectional view illustrating another form of the electromagnetic wave shielding material according to the present invention (a transparent layer also serving as a flattening layer), FIG. 5 is a cross-sectional view conceptually showing an example of conduction in the ground region, FIG. 6 is a cross-sectional view illustrating another form (addition of a metal thin film layer) of the electromagnetic wave shielding material according to the present invention, and FIG. It is a conceptual diagram explaining the novel printing method used as an opportunity, and is a conceptual diagram explaining the novel intaglio printing method utilized with the electromagnetic wave shielding material of this invention with the one aspect | mode.

[Outline by representative composition]
The electromagnetic wave shielding material according to the present invention is formed by laminating a primer layer 12 (solidified) on a transparent substrate 11 like the electromagnetic wave shielding material 10 shown in FIG. The conductive ink printing layer 13 is printed on the primer layer 12 and printed in a predetermined pattern, and the opening 14 which is a portion where the conductive ink printing layer 13 is not printed and bears light transmittance. The surface of the primer layer 12 has a concavo-convex shape 15, and the transparent layer 16 that fills and smoothes the concavo-convex shape 15 is only the primer layer 12 in the opening except for the conductive ink printing layer portion. On the other hand, it is the structure formed in the whole surface in an opening part also including the opening part which does not have uneven | corrugated shape.

As shown in FIG. 2, the thickness Ta of the primer layer 12 in the conductive ink printing layer 13 portion (directly below) may be thicker than the thickness Tb of the primer layer at the opening, or may be equal to Ta and Tb. .
Further, the transparent layer 16 may be formed at least in the portion where the uneven shape 15 of the primer layer 12 is present, but the entire surface in the opening where the uneven shape exists, and a plurality of openings including the opening where the uneven shape does not exist. You may form all the opening parts, or also including the conductive ink printing layer 13 with an opening part (refer FIGS. 3-5). Especially, the last structure formed on both the opening and the conductive ink printing layer is preferable in that it can be easily formed.

[Transparent substrate]
The transparent substrate 11 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as light transmittance, mechanical strength, and further ionizing radiation transparency. A rigid material such as a plate or a resin plate may be used, but a flexible resin film (or sheet) is preferable in consideration of suitability for continuous processing in roll-to-roll which is excellent in productivity.
Examples of the resin for the resin film include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acrylic resins such as polymethyl methacrylate, polyolefin resins such as cycloolefin polymers, cellulose resins such as triacetyl cellulose, and polycarbonate. Resin. Among these, a biaxially stretched film of polyethylene terephthalate is a preferable transparent substrate in terms of mechanical strength, light transmission, ionizing radiation transmission, cost, and the like.
The thickness of the transparent substrate is basically not particularly limited and is appropriately selected depending on the application and the like. When a flexible resin film is used, it is, for example, about 12 to 500 μm, preferably about 25 to 200 μm.

In addition, known additives such as an ultraviolet absorber, an infrared absorber, a colorant, a filler, a plasticizer, and an antistatic agent can be appropriately added to the resin of the transparent substrate as necessary. In addition, the UV absorber is hardened by irradiation of ionizing radiation to solidify the primer layer when printing conductive ink, and when UV light is transmitted through a transparent substrate, it should be added to the extent that does not hinder the curing. If you choose not to completely inhibit the absorption wavelength range of ultraviolet absorbers and the wavelength range of ultraviolet rays used for curing (use wavelength range of photopolymerization initiator) good.
The transparent substrate may be subjected to a known easy adhesion treatment such as a corona discharge treatment or an easy adhesion primer treatment using a material / formation method different from that of the primer layer 12 on the surface.

[Primer layer]
The primer layer 12 is a layer for the purpose of improving the ink transfer property from the plate to the printing material and improving the ink adhesion between the transferred ink and the printing material when the conductive ink printing layer is formed by printing. is there. In addition, as a basic function, both the transparent base material and the conductive ink printing layer have good adhesion, and it is also a transparent layer for ensuring light transmittance at the opening. The primer layer may be a single layer or multiple layers.
Further, the primer layer 12 is a layer formed as a layer that is solidified from a liquid while in contact with the intaglio at the time of intaglio printing, and is solidified when finally becoming an electromagnetic shielding material. Formed as a layer. By using such a layer, a phenomenon different from a general so-called “adhesive primer layer”, an anchor layer, an underlayer, etc. formed as a layer that has already solidified before printing and a favorable result (effect) ) Is as described above.

[What is liquid]
The liquid of the primer layer may be in a liquid state when it is in contact with the intaglio, may be liquid before contacting the primer with the intaglio, and is in contact after the primer layer is in contact with the intaglio. It may be liquid during the process. If the primer is applied to the transparent substrate in advance, the primer immediately before the contact with the intaglio at the time immediately after the primer is applied to the transparent substrate, or the time after the primer if heated and dried. It does not limit the liquid or solid state of the layer. Therefore, for example, the primer layer may be once in a solid state before contacting the plate after applying the primer to the transparent substrate. In this case, for example, it is softened by heating (including heating and melting) to form a liquid.
However, it is formed as a liquid primer layer from the beginning of applying the primer to the transparent substrate, and remains in the liquid state (the solvent may be dried after applying the liquid), and is in contact with the intaglio for the first time. Solidifying is liquid, solidified, liquid, solidified and does not need to change state and is efficient in process.

  The “liquid” may have a low viscosity like water, but such a low viscosity is not essential. For example, when the primer layer is in contact with the intaglio, the intaglio depression was filled by the pressure applied to the intaglio by a pressure roller such as a nip roller or an impression cylinder on the transparent substrate to which the primer was applied. If there is a dent in the ink, it should be at least fluid enough to allow the liquid primer layer around the recess to flow and flow into at least part of the dent, and more preferably to fill the dent completely. It only needs fluidity. Therefore, the liquid state should have a certain degree of fluidity (deformability) that tends to reduce the depression when there is a depression. Even if there is no dent, if there is enough fluidity to reduce the dent, the liquid (primer layer) and the liquid (conductive ink) are brought into contact with each other by “liquid / liquid contact”. An effect of improving printing defects such as lack is obtained.

In order to make the primer layer liquid, a primer that is liquid at room temperature even without solvent is used, or a primer that can form a primer layer that becomes liquid by heating (for example, about 50 to 200 ° C.). The former uses an uncured room temperature liquid ionizing radiation curable resin primer, the latter uses solvent coating or melt coating, uncured room temperature solid ionizing radiation curable resin, uncured room temperature solid thermosetting resin, heat A primer made of a plastic resin or the like may be used.
Although a solvent may be added to the primer, the primer layer on the plate is solidified only by the action of the solvent because it proceeds in a closed system with the intaglio and the transparent substrate sandwiched between the front and back. Since it cannot be solidified by solvent drying, the additive solvent should be dried before contacting the plate, or added in such an amount that does not hinder solidification even if it remains after contact.

[Thickness Ta> Tb]
As described above with reference to FIG. 7, in the new intaglio printing method employing the present invention, printing is performed through a liquid primer layer that is solidified during printing as described above, the plate surface is formed on the upper surface of the ink 34 filled in the recess. Even when the depression 35 is not flush with the convex portion (same level surface), the primer layer 32A interposed between the printing medium and the intaglio and in contact with the intaglio is in a liquid state, so it flows into the depression and fills the gap. Improves incomplete contact due to the gap between the printing material 31 and the ink at the ink depression, realizing a more perfect contact state, eliminating printing defects due to insufficient ink transfer and insufficient ink adhesion, etc. The transfer rate is also improved.
Further, in the new intaglio printing method adopted in the present invention, even if there is no depression in the ink filled in the recess, the primer layer is in liquid form and in liquid-liquid contact with the liquid ink in the recess, and then at least the primer layer Compared with the case where liquid ink is brought into contact with the solid primer layer from the beginning, the adhesion between the primer layer and the ink is increased, the adhesion between the transparent substrate and the ink is improved, and the ink transfer property is improved. An effect is obtained and printing defects are improved.

Thus, when there is a depression, as shown in FIG. 2, the thickness of the primer layer is greater than the thickness Tb of the opening, the thickness Ta immediately below the conductive ink printing layer (corresponding to the depth of the depression). When the phenomenon is observed and ink filling is ideal and there is no depression, a phenomenon is observed in which the thickness of the primer layer is equal to the thickness Tb of the opening and the thickness Ta immediately below the conductive ink printing layer. Even when there is a depression, the depression does not necessarily occur in all the concave portions on the plate surface.
Further, the cross-sectional shape of the primer layer thickened at the conductive ink printing layer portion is a shape in which the thickness becomes thicker toward the center in the line width direction of the conductive ink printing layer in FIG. The so-called bell-shaped shape, the so-called mountain shape such as a triangle, trapezoid, and pentagon, or a shape similar thereto may be used. A shape in which the thick part is shifted to either of the both ends in the width direction or a wave shape having a plurality of thick parts may be used. In addition, since the primer and the ink are in contact with each other in a liquid state, the shape of the contact surface essentially includes variation (surface disturbance). Therefore, when viewed in the line width direction of the cross section, the possibility that the thickness of the mountain-shaped skirt portion of the primer is thinner than the opening thickness Tb is not zero. However, in such a case, the effect of the present invention is not disturbed.
FIG. 2 illustrates the case where the thickness Ta of the primer layer is the thickest at the center portion directly below the conductive ink printing layer, and the thickness Ta is representatively shown by the maximum thickness portion. It may be anywhere as long as it is directly under the printing layer, but may be represented by the maximum thickness.
Depending on the materials used and printing conditions, generally, the primer and ink diffuse, dissolve or permeate each other in the vicinity of the interface between the primer layer 32 and the ink 34. As a result, in addition to the filling effect by the primer of the depression on the upper surface of the filling ink in the plate recess, the adhesion between the layers may be improved and the fluidity of the ink 34 itself may be lowered. In this case, these effects are also added, and the effect of improving the transfer of ink in the recesses is further improved.

  The thickness of the primer layer is not particularly limited, but is usually 1 to 100 μm in thickness Tb at the opening after solidification. Further, when the thickness Ta of the conductive ink printing layer portion is thick, the thickness of the portion increases accordingly.

〔material〕
The material used for the primer layer 12 is basically not particularly limited as long as it can be solidified from a liquid state to a solid state on the plate when in contact with the plate. Specifically, the primer layer 12 can be formed as a resin layer. As the resin of the resin layer, a thermoplastic resin or a curable resin can be used. As the curable resin, an ionizing radiation curable resin, Thermosetting resins, curable resins with other curing mechanisms, and the like can be used. Among them, the ionizing radiation curable resin, which is a kind of curable resin, is formed as a liquid primer layer from the beginning on a transparent substrate, and is supplied to the plate as a liquid so that it can be quickly solidified on the plate. In view of excellent productivity, it is preferable. However, another curable resin such as a thermosetting resin or a thermoplastic resin may be used from the viewpoint of the cost of an ionizing radiation irradiation apparatus and the like, and available equipment.

  Here, if the specific example of the said resin is given, as a thermoplastic resin, it will be an acrylic resin, a polyester-type resin, a urethane-type resin, an olefin resin etc., for example. Examples of the thermosetting resin include a thermosetting acrylic resin, a thermosetting urethane resin, and an epoxy resin.

Further, as the ionizing radiation curable resin, a resin that can be used in a liquid state in an uncured state (including those that become liquid at room temperature and those that become liquid at room temperature solid by heating, solvent dilution, etc.) may be selected. It should be noted that the ionizing radiation curable resin is at least cured with ionizing radiation, and is appropriately blended with monomers, oligomers, prepolymers, etc., or further for adjusting physical properties, etc. A resin composition in which an additive resin and other additives are appropriately blended, and is a resin that can be cured by ionizing radiation.
Examples of such ionizing radiation curable resins include radical polymerizable compounds typified by acrylate and cationic polymerizable compounds typified by epoxy. As the acrylate system, monofunctional or bifunctional or higher (meth) acrylate monomers, (meth) acrylate prepolymers, and the like are used. (Meth) acrylate means acrylate or methacrylate. Examples of acrylate monomers include methyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. Etc. are used. In addition, polyester-based, urethane-based, epoxy-based, melamine-based, silicone-based, and the like are used for the acrylate-based prepolymer. Examples of the epoxy type include prepolymers such as novolac type epoxy type and bisphenol type epoxy type.

  As ionizing radiation, ultraviolet rays, electron beams and the like may be appropriately selected. However, ultraviolet rays are preferred in that they are inexpensive in terms of equipment. In the case of ultraviolet rays, a resin containing a photopolymerization initiator is used. In addition, when using a transparent base material with an ultraviolet absorber added to the resin to improve light resistance, if irradiation with ultraviolet light through the transparent base material may interfere with curing, an electron beam It is preferable to use this. In addition, when an ultraviolet absorber is added to the ionizing radiation curable resin to improve light resistance, it is preferable to cure using an electron beam.

  Further, various additives can be further added to the primer layer as necessary. What is necessary is just to select a well-known thing suitably as an additive. For example, additives such as plasticizers, surfactants, extender pigments, antistatic agents, heat stabilizers, light stabilizers (ultraviolet absorbers, radical scavengers), infrared absorbers, and colorants.

[Applying primer]
In addition, what is necessary is just to employ | adopt a well-known coating method suitably as a method of giving a primer to a transparent base material and forming a primer layer. For example, if a thermoplastic resin is used to make it liquid by heating and softening, the primer layer added with a solvent is coated and then dried to form a primer layer that is once solidified before contacting the plate. Alternatively, after the primer is melt-coated, it is cooled and solidified to form a primer layer once solidified before contacting the plate. Alternatively, after the primer is melt-coated, it is formed as a heat-softened liquid primer layer without being cooled and solidified (supplied to the plate and solidified after contact).
In the case of an ionizing radiation curable resin, if it is uncured and solid at room temperature, it can be the same as the above thermoplastic resin, and if it is uncured (room temperature or heated), a liquid primer is applied as it is. Alternatively, a solvent-diluted primer solution is applied and dried to form a liquid primer layer as it is (solidified after contact with the plate). Even in the case of melt coating, a solvent may be added to the coating solution as long as it does not hinder solidification on the plate.
Specific examples of the coating method include gravure coating, comma coating, die coating, and roll coating.

  The primer layer may be solidified from a liquid state to a solid state in contact with the intaglio, and in order to realize this, the primer is not applied to the transparent base material in advance, but the conductive ink is filled only in the concave portion and the transparent base material is used. It may be applied to the intaglio before contact, and both this method and the method applied to the transparent substrate may be used in combination. When applying a primer to a transparent substrate, compared to applying both the primer and the conductive ink to the intaglio, each application amount is easy to control independently, and it is preferable in that the periphery of the apparatus plate is not complicated. . On the other hand, when both the primer and the conductive ink are applied to the intaglio, it is preferable in that a single unit device in which the primer coating unit and the conductive ink printing unit are integrated can be obtained.

[Solidification]
In order to solidify the liquid primer layer in contact with the intaglio, chemical reaction, cooling, or a combination thereof can be used.
For example, when a curable resin is used, it is solidified by a chemical reaction, when a curable resin or a thermoplastic resin is liquefied by heating, it is solidified by cooling, or when it is liquefied by heating using a curable resin. Solidification by a combination of cooling and chemical reaction can also be employed. The solidification by chemical reaction is typically a crosslinking reaction, that is, a curing reaction, but may be a reaction that solidifies without crosslinking.
For chemical reaction, typically, ionizing radiation irradiation can be used for ionizing radiation curable resins, and heat curing can be used for thermosetting resins. For solidification by cooling, cooling by the intaglio plate itself, cooling using a pressure roller that presses the transparent substrate against the intaglio plate as a cooling roller, or cooling using a combination thereof may be employed. In addition, when liquefied by heating and solidified by cooling, it is more effective to cool what is liquefied by heating on the transparent substrate than to sequentially heat and cool on the same intaglio. It is efficient in use and suitable for high-speed processing.

In addition, solidification by chemical reaction may be semi-cured (partially advanced) without completely proceeding with chemical reaction if solidified to such an extent that it can be released, and may be allowed to proceed completely after release. If it is completely advanced before, the chemical reaction operation is completed in one step. In particular, when the chemical reaction rarely proceeds instantaneously like a thermosetting resin, it is preferable in terms of productivity to complete the chemical reaction after the release of the plate. Further, when the curable resin is heated and liquefied, it may be cooled and solidified on the plate or solidified by a combination of cooling and chemical reaction, and the chemical reaction may be completed after release.
In this way, various solidification methods can be adopted, and in particular, ionizing radiation irradiation can complete a chemical reaction instantly, so it is suitable for solidification on a cylindrical intaglio plate requiring high-speed solidification, and has excellent productivity. Also, the corresponding ionizing radiation curable resin is an excellent solidification method in that it can be handled in a liquid state from the stage of applying the primer.

[Uneven shape]
The uneven shape 15 present in the opening of the primer layer is a micro crack on the plating surface when the plate surface is chrome-plated for surface durability, surface roughness, scratches on the doctor blade, and when the plate surface is polished. An uneven shape on the surface of the intaglio convex part such as a polishing flaw, or an uneven shape formed during printing formation of the conductive ink printing layer due to the inclusion of dust or the like. Any of these is an unevenness that is inevitably generated although it is not originally desired, and is different from a plate recess for imparting a predetermined pattern to the conductive ink. Even if it says an uneven | corrugated shape, the concave shape hollow from the primer layer surface, the bulging convex shape, and the uneven | corrugated shape which literally combined the concave and convex are all shapes to be smoothed by the transparent layer.
In addition, as the concavo-convex shape, the concavo-convex shape that triggered the present invention was a streaky concavo-convex shape such as a scratch or a crack, but the concavo-convex shape present substantially uniformly over the entire surface of the opening of the primer layer Since the shape (for example, matte unevenness) can be smoothed by the transparent layer, it is an object of the transparent layer.

[Conductive ink printing layer]
The conductive ink printing layer 13 is a layer formed by printing conductive ink in a predetermined pattern. In the present invention, the novel intaglio printing method is used for the printing. The predetermined pattern is a known pattern in which both electromagnetic shielding performance such as mesh shape and stripe shape and light transmittance are compatible. Among them, a mesh shape and a square lattice shape are typical, and in addition, examples of the lattice shape include a rectangular lattice, a rhombus lattice, a hexagonal lattice, and a triangular lattice. The line width of the pattern is 5 to 50 μm, for example, and 5 to 30 μm, which is finer in terms of the effect of the present invention, and the line pitch (line-to-line repetition period) is 100 to 500 μm, for example.
Note that in display applications, the periphery of the four sides that do not affect the image display may be a solid pattern that does not have an opening for grounding conduction, or a grounding region that has a small occupied area ratio even if it exists.

  The conductive ink is an ink in which conductive powder is dispersed in a resin binder, and the resin binder includes a resin and, if necessary, a solvent and other additives. In addition, what is necessary is just to employ | adopt well-known as a conductive ink suitably.

[Conductive powder]
Examples of conductive powders include low resistivity metal powders such as gold, silver, copper, platinum, tin, nickel, and aluminum, or other high resistivity metal powders, resin powders, non-metallic inorganic powders, etc. Powders whose surfaces are plated with the above-mentioned low resistivity metals such as gold and silver, or graphite or carbon black powders, etc., which finally give conductivity to the conductive ink printing layer, are used. A known material can be used as appropriate.
The conductive powder has a spherical shape, a spheroid shape, a scale shape, a disk shape, a polyhedron shape, a truncated polyhedron shape, a fiber (needle) shape, and the like. A plurality of powders having different materials and shapes may be used in combination. As for the size of the conductive powder, for example, a flaky silver powder having an average particle size of 0.1 to 10 μm can be used, and a carbon black powder having an average particle size of 0.01 to 1 μm can be used. . In addition, an average particle diameter is a measured value obtained from a particle size distribution diameter or a transmission electron microscope (TEM) observation.
Moreover, the ratio in the conductive ink of electroconductive powder is selected suitably, for example, is 40-99 mass parts with respect to 100 mass parts of conductive ink solid content.

[Resin binder]
As the resin used for the resin binder, a thermoplastic resin or a curable resin can be used. As the curable resin, an ionizing radiation curable resin, a thermosetting resin, other curable resins, or the like can be used. As these resins, known resins can be appropriately used as the conductive ink. Examples of thermosetting resins include polyester-melamine resins, epoxy-melamine resins, other melamine resins, phenol resins, polyimide resins, thermosetting acrylic resins, and thermosetting urethane resins. As the ionizing radiation curable resin, the resins described in the primer layer and the transparent layer described later can be used, and as the thermoplastic resin, a polyester resin, a polyvinyl butyral resin, an acrylic resin, a heat resin, etc. A plastic polyurethane resin or the like can be used.

〔Additive〕
Examples of the additive include a filler, a thickener, a surfactant, an antioxidant, and a colorant. The colorant is, for example, a pigment or dye that colors the ink black. When the conductive powder itself is not black, the black colorant improves the contrast when the display is applied by coloring the ink black, or when a metal thin film layer is additionally provided on the conductive ink printing layer. Used to hide the metallic luster on the transparent substrate side. The black pigment is carbon black, Fe ₃ O ₄ , CuO—Cr ₂ O ₃ , CuO—Fe ₃ O ₄ —Mn ₂ O ₃ , CoO—Fe ₂ O ₃ —Cr ₂ O _3, etc. The particle diameter is preferably 0.1 μm or less, for example, in terms of coloring power. As carbon black, in addition to carbon black for color materials such as channel black, conductive carbon black such as acetylene black can be used, and the average particle size is preferably 20 nm or less. Moreover, aniline black etc. can be used for a black dye.

[intaglio]
In addition, the intaglio printing the conductive ink printing layer may be flat or cylindrical (cylinder), but the cylindrical intaglio is a roll of continuous strip (web) on a transparent substrate. Continuously (intermittent feeding) in two rolls (a process in which a continuous belt-like sheet is supplied by winding (rolling), the sheet is unwound into a belt and processed as desired, and then wound up again and stored by winding) From the viewpoint of productivity.
In addition, when an intaglio is cylindrical, it is also called a roll intaglio. When the intaglio plate is cylindrical, the plate surface recess may be a seamless endless plate that is continuous in the circumferential direction or may have a seam. In order to form a concave portion corresponding to a predetermined pattern shape on the printing plate, it can be formed by a known method such as photolithography or machining by a cutting method.
The material of the intaglio may be a general metal such as copper or iron, or an ionizing radiation opaque material such as opaque ceramics, but if an ionizing radiation transparent material such as quartz is used, it will be blocked from the inside of the hollow intaglio. The primer layer and the conductive ink can be cured by irradiating ionizing radiation from the intaglio side.

  In order to fill the ink in the concave portion of the intaglio plate and remove excess ink on the convex portion of the plate surface, it may be scraped off by a conventionally known means, for example, a doctor blade, as in the case of the gravure printing plate. Ink supply to the plate surface may be performed by a conventionally known ink supply means such as an applicator roller.

[Intaglio printing of conductive ink]
In order to form a conductive ink printing layer having a predetermined pattern by intaglio printing with conductive ink, for example, only a concave portion of the intaglio plate is filled with conductive ink using a doctor blade or the like, and a primer layer to be liquefied is applied to one side. The formed transparent substrate is brought into contact with the primer layer by, for example, pressing with a pressure roller so that the primer layer is in contact with the intaglio, and the primer layer is solidified from a liquid state to a solid state in the contact state. Thereafter, the transparent base material is separated from the intaglio plate and released to transfer the ink onto the solidified primer layer on the transparent base material.

After printing, that is, after release, the conductive ink printed layer that is still liquid is appropriately subjected to a drying operation, a heating operation, a cooling operation, a chemical reaction operation, and the like to complete a conductive conductive ink printed layer. For example, the drying operation removes unnecessary volatile components such as the solvent in the ink, and the heating operation promotes necessary chemical reactions such as drying and thermal curing of the ink. Therefore, the cooling operation is performed on the ink and the primer layer. In order to promote solidification, the chemical reaction operation is performed in order to advance the chemical reaction of the ink or primer layer by other means such as ionizing radiation irradiation without heating.
The conductive ink may be semi-cured and solidified on the plate and completely cured after release.

  The solidification of the conductive ink may be performed during contact with the intaglio. When the conductive ink is solidified during the plate contact, the intaglio serves as a shaping mold for the conductive ink, and the intaglio including the primer layer is used as a complete shaping mold. At this time, the solidification method of the conductive ink may be the same as the solidification method employed in the primer layer, or may be a different method. However, if the same method such as ionizing radiation irradiation is adopted, it can be simplified in terms of apparatus and process, and if a similar chemical reaction is adopted, it is advantageous in terms of adhesion.

  In the present invention, since printing is performed in this way, even if a depression is formed in the upper part of the conductive ink filled in the intaglio recess, printing is performed via the liquid and fluid primer layer. Is poured into the depression and brought into close contact with the gap, and then the primer layer is solidified and then the transparent substrate is released from the intaglio, so that the conductive ink printing layer of a predetermined pattern is passed through the primer layer solidified on the transparent substrate. Even a fine wire can be formed without the occurrence of printing defects such as disconnection due to insufficient transfer, shape failure, and insufficient ink adhesion.

  In addition, the interface between the conductive ink printing layer and the primer layer is not only in the form of physical or chemical adhesion, but in the vicinity of the interface, the materials of both layers dissolve, permeate, or diffuse to each other. It may be a form. The latter is achieved by adjusting the material, solidification / curing conditions, printing conditions, and the like, and the latter is preferred in terms of adhesion and the like.

[Transparent layer]
The transparent layer 16 covers the irregularities 15 on the surface of the primer layer at the openings, and the irregularities are dulled and smoothed on the surface of the transparent layer in the coated portion, preferably completely smooth. Thus, the transparency of the haze increased and decreased by light diffusion and light scattering due to the uneven shape is recovered even a little, and the layer approaches the original transparency when there is no uneven shape. Therefore, the transparent layer itself is also a transparent layer from the viewpoint of ensuring the light transmittance of the opening. As long as the transparent layer satisfies these functions, the material and the forming method are not particularly limited. A representative resin layer is a resin layer formed by coating, but the layer formation may be performed by a printing method in addition to the coating method, and a known film forming method such as a transfer method or a laminating method may be appropriately employed.

In addition, the transparent layer may cover at least the portion where the uneven shape exists in the opening, but usually both the opening including the uneven shape and the opening where there is no uneven shape are included. It is preferable to provide the opening so as to cover the primer layer because selective formation is unnecessary and coating formation is easy.
In addition, the transparent layer is necessarily provided after the formation of the conductive ink printing layer, and is essentially unnecessary on the surface of the conductive ink printing layer, but the surface of the conductive ink printing layer is easy in terms of easy coating formation. It is preferable to form without distinction (see electromagnetic wave shielding material 10 in FIGS. 3 to 5).

  Moreover, the transparent layer covering the primer layer also has a function as a protective layer for protecting the primer layer from scratches and dirt as an incidental function. The conductive ink printing layer also has a function as a protective layer for protecting from scratches and dirt. When these protective layers are final surfaces, they are surface protective layers.

[Optimization of refractive index]
Moreover, it is preferable to optimize the refractive index nt of the transparent layer. That is, the relationship between the refractive index np of the primer layer, the refractive index nt of the transparent layer, and the refractive index na (1.00) of air is | np−nt | <| np−na |. That is, the refractive index difference (| np−nt |) between the transparent layer and the primer layer is made smaller than the refractive index difference (| np−na |) between the primer layer and air. Thereby, the optical transparency effect which provided the transparency layer is acquired, and the transparency fall by uneven | corrugated shape on the surface of a primer layer can be suppressed (or recovered | restored), and transparency can be improved and improved.
Further, in order to obtain a practically preferable effect, the difference in refractive index between the transparent layer and the primer layer is preferably 0.30 or less, more preferably 0.14 or less. More preferably, the refractive index nt of the transparent layer and the refractive index np of the primer layer are substantially equal. Substantially the same may be completely the same (refractive index difference 0.00), but the refractive index difference | np−nt | ≦ 0.05 is sufficient in that the increase in haze can be ignored in practice.
In order to reduce the difference in refractive index to substantially the same level, it is easy to use the same material for the primer layer and the transparent layer, but different materials may be used in consideration of the adhesion to the adjacent layer. .

Note that the haze characteristics to be recovered by the transparency by the transparent layer is preferably recovered to 6.0% or less, more preferably 3.0% or less, when measuring as an electromagnetic wave shielding material.
The haze is measured according to JIS K-7136 (2000) “Plastics—How to determine haze of transparent material”.

  Here, if refractive index n which various resin can take is illustrated, acrylic resin (n = 1.49), acrylate type ionizing radiation curable resin (n = 1.48-1.50), unsaturated polyester resin (N = 1.52 to 1.57), urethane resin (n = 1.50 to 1.60), and the like. A resin is appropriately selected to form a layer having a desired refractive index.

〔material〕
The resin used for the transparent layer may be appropriately selected in consideration of required physical properties such as adhesion to adjacent layers, coating suitability, and transparency in addition to the refractive index. For example, a thermoplastic resin or a curable resin can be used as the resin, and an ionizing radiation curable resin, a thermosetting resin, another curable resin, or the like can be used as the curable resin. For example, examples of the thermoplastic resin include acrylic resins, urethane resins, polyester resins, olefin resins, vinyl resins, cellulose resins, fluorine resins, silicone resins, and vinyl chloride resins. Examples of the thermosetting resin include thermosetting acrylic resins, thermosetting urethane resins, epoxy resins, polyester resins, and silicone resins. Acrylic and silicone rubber resins can also be used in various resin forms such as thermoplastic, thermosetting, and ionizing radiation curable.

The ionizing radiation curable resin may be liquid or solid at room temperature when uncured. The ionizing radiation curable resin is a monomer, oligomer, prepolymer or the like that can be cured with ionizing radiation, or for adjusting physical properties, for example, an ionizing radiation non-curable resin such as thermoplastic or thermosetting, It is a resin composition in which other additives are appropriately blended, and can be cured by ionizing radiation.
Such an ionizing radiation curable resin may be appropriately selected from those similar to those described above as examples of the resin for the primer layer. Duplicate description is omitted.

  As ionizing radiation, ultraviolet rays, electron beams and the like may be appropriately selected. When an ultraviolet absorber is added to the ionizing radiation curable resin to improve light resistance, an electron beam may be used.

  Further, various additives can be added to the transparent layer as necessary. What is necessary is just to select a well-known thing suitably as an additive. Examples of the additives include plasticizers, surfactants, extender pigments, heat stabilizers, light stabilizers (ultraviolet absorbers, radical scavengers), infrared absorbers, and colorants. Examples of the colorant include a near-infrared absorbing dye, a neon light absorbing dye, and an image color correcting dye. The colorant may be added when the planarizing layer is also used.

[Combined with flattening layer]
The transparent layer 16 may also cover the conductive ink printing layer 13 like the electromagnetic wave shielding material 10 illustrated in FIG. 4, rather than selectively covering only the surface of the primer layer 12 of the opening 14. The formation of a transparent layer is facilitated. When the conductive ink printing layer is also covered, when the thickness of the transparent layer is thicker on the primer layer of the opening than on the conductive ink printing layer, the surface step D between the conductive ink printing layer portion and the opening is As a result, the transparent layer becomes a layer that also serves as a flattened layer (flattened and transparentized layer 16a) (FIG. 4 shows an example in which the level difference completely disappears on the surface of the transparentized layer).
Further, even when the transparent layer 16 selectively covers only the surface of the primer layer 12 of the opening 14 like the electromagnetic wave shielding material 10 illustrated in FIG. 1, the conductive ink printing layer 13 after the transparent layer is formed. On the surface of the electromagnetic shielding material on the side, the level difference between the surface of the conductive ink printed layer portion and the opening is equal to the level difference d <level difference D with respect to the level difference D immediately before the formation of the transparent layer. Since the thickness is reduced by the thickness of the transparent layer, the transparent layer 16 becomes a flattened transparent layer 16a that also serves as a flattened layer.

As described with reference to FIGS. 1 and 4, planarization is to reduce the step D on the surface of the electromagnetic ink shielding material on the side of the conductive ink print layer 13 and the opening 14 at the conductive ink print layer 13 portion. It is ideal to completely eliminate the reduction, but it can be reduced even if it is not completely eliminated.
A clearing layer (same as a simple flattening layer) reduces the level difference of the surface. The surface of the forming layer immediately after the layer formation with respect to the surface of the flattening transparentizing layer (or flattening layer) immediately before the layer formation. It is to reduce. In FIG. 4, the surface of the opening constituting the level difference D immediately before the formation of the transparent layer is an example of the primer layer surface, and the surface of the conductive ink printing layer portion is an example of the surface of the printing layer itself. In addition, the surface of the conductive ink printing layer “part” is, as a matter of course, a metal thin film layer to be described later is further formed (see FIG. 6), and then a flattened transparent layer (or flattened layer) is formed. It becomes the surface of the metal thin film layer.
If the transparent layer is a flattened transparent layer, the step due to the conductive ink printing layer can be reduced by providing a single flattened transparent layer without providing a dedicated flattening layer on the transparent layer. Flattening can be performed, and entrapment of bubbles when an additional layer such as an optical functional layer is laminated can be suppressed.

  Even when bubbles are trapped at the level difference, when the flattened transparent layer is an adhesive layer, the bubbles can be eliminated by pressurization and heating in an autoclave. However, if the level difference is set to 5 μm or less by flattening, it is possible to suppress the entrapment of bubbles itself, the autoclave treatment step itself can be omitted, and if it is further set to 1 μm or less, the bubbles can be more reliably suppressed. Therefore, an advantage that one step of the autoclave treatment step can be omitted by the flattened transparent layer is also obtained.

In the case where a transparent layer is also formed on the flattened transparent layer and the conductive ink printing layer, the transparent layer may be an adhesive layer, an adhesive layer, or the like for adhering to other layers. In the case of the adhesive layer, a known adhesive such as an acrylic resin may be used.
In the case of a mere flattened layer that does not require a function as a transparent layer, that is, there is no uneven shape that causes a decrease in transparency on the surface of the opening primer layer, but the step due to the conductive ink printing layer is reduced. Then, it is not necessary to pay particular attention to the relationship between the refractive index of the planarizing layer and the refractive index of the primer layer.

In order to completely or almost completely eliminate the level difference on the surface of the transparentized layer including the conductive ink printed layer, which is a flattened transparentized layer, a coating liquid for forming the transparentized layer is formed on the conductive ink printed layer forming surface. It is possible to achieve more complete flattening by laminating a separator film on top of a solvent-free coating solution as much as possible, and pressing the surface of the separator film with a laminating roller to level the surface. . Alternatively, a laminated film in which a pre-transparent layer that becomes a thermoplastic state such as an adhesive layer is formed on a separator film may be laminated on the conductive ink print layer forming surface and pressed with a roller. These separator films peel after flattening.
Or the film used as functional layers, such as a coloring filter and a hard-coat layer, is used instead of a separator film, and does not need to peel after planarization.
By such a roller pressure treatment, the step remaining immediately after the flattening layer is formed can be further reduced, and can be reduced to 1 μm or less.

[Covering and grounding support for conductive ink printed layers]
By the way, a grounding region may be provided in the conductive ink printing layer. The grounding area has a solid pattern of conductive ink that does not have openings around the conductive ink printing layer formed with a predetermined pattern (such as a mesh shape) having openings, or an opening (light-transmitting property). This is a region in which a ground pattern having a solid surface area whose area ratio is smaller than that of the inner region is formed by the conductive ink printing layer. To give a specific example of such a grounding region, the periphery of the patterned opening region is surrounded by a solid layer having a width of about 10 to 40 mm in the form of a frame to surround the entire periphery of the four sides, thereby forming a conductive ink printing layer in the opening region inside. It is a connected and conductive area.

Note that the whole surface solid approximation means that, even in the intaglio used in the present invention, only the grounding region is similar to a general gravure printing plate between the concave portions (cells) adjacent to the whole surface solid portion. The plate surface convex part (bank) which surrounds is arranged to divide the concave part. That is, in the ground contact area, an opening is essentially indispensable. However, in intaglio printing without a cell section, a large continuous concave portion cannot stably secure an ink filling space. Depending on the fluidity of the ink after release, an opening corresponding to the bank portion of the conductive ink printing layer (which does not contribute to light transmission) is present or absent. Insufficient fluidity of the ink after release, and when the conductive ink patterns (dots) transferred from the partitioned concave portions (cells) are independent from each other, the conductivity cannot be ensured. In such a case, it is possible to substitute the area ratio of the opening of the grounding region extremely small, such as by narrowing the line spacing of the mesh shape or increasing the line width in the grounding region.
The ground pattern may be formed simultaneously with the mesh pattern, or after the mesh pattern is formed, conductive ink may be printed on the ground area separately. However, it is preferable that the ground pattern is formed as much as possible from the viewpoint of simplification of the process.

  If the conductive ink printing layer in the grounding area is coated with an insulating transparent layer, and there is a problem with grounding, the transparent layer is partially formed, and the part necessary for grounding in the grounding area is not covered and exposed. And good. The transparent layer may be partially formed by a known printing method, but depending on the pattern to be partially formed, the coating method can be applied by intermittent coating or selective coating in the width direction.

Further, as illustrated in FIG. 5, even when the conductive ink printing layer 13 is covered with the transparent layer 16 in the ground region 18 b on the outer periphery of the opening region 18 a, the transparent layer is formed by the protrusions 21 provided on the ground member 20. May be made to pass through the conductive ink printing layer. The projection 21 may be arbitrarily pointed or line-shaped in a plan view, and is usually arranged at a place where a plurality of projections are conducted. Moreover, the protrusion 21 may penetrate the conductive ink printing layer to reach the inside of the transparent base material 11 (see FIG. 5), and may further penetrate the transparent base material 11 (not shown).
In the electromagnetic wave shielding material 10 illustrated in FIG. 5, the transparent layer 16 also covers the conductive ink printing layer 13, and the surface is completely flat with the same surface (same level surface over the entire surface). Although it is also a form example of the chemical layer, the uneven shape on the surface of the primer layer is not shown.

[Metal thin film layer]
The electromagnetic wave shielding material 10 illustrated in FIG. 6 is an example in which a metal thin film layer 17 is provided as a metal plating layer, for example, on the surface of the conductive ink printing layer 13. The metal thin film layer is usually provided when the surface resistance is still high with the conductive ink printing layer alone and the electromagnetic wave shielding performance is insufficient. In addition, the conductive ink printing layer can be formed by reducing the conductive ink as long as the surface resistance that can be plated can be secured.
The metal thin film layer may be formed by a known metal thin film forming method, and a plating method, a vacuum deposition method, a sputtering method, or the like can be applied. However, in addition to depositing a metal layer on the conductive ink printed layer, a plating method using a metal ion solution is suitable when the gap inside the conductive ink layer or the conductive powder is connected by a metal thin film. is there. As the plating method, either electroless plating or electrolytic plating can be applied. When depositing a thin metal film at a high speed, electrolytic plating is preferable in terms of productivity and cost. On the other hand, the metal of the metal thin film layer is copper, silver, gold or the like. Among them, copper is preferable because of its excellent cost and conductivity. The metal thin film layer may use a plurality of metals or may be a multilayer.
The metal thin film layer is usually formed before the transparent layer is formed while the exposed surface of the conductive ink printed layer is secured.
Further, the surface of the metal thin film layer may be further blackened to provide a blackened layer or a rust preventive layer made of a metal compound. These can be provided by a known process.

Additional layers
In addition to the above-described layers such as the transparent substrate, primer layer, conductive ink printing layer, transparentizing layer, and metal thin film layer, other layers can be further added as necessary. For example, an optical filter layer, an optical functional layer that imparts an antireflection function (antiglare, antireflection, antiglare and antireflection), a surface protective layer that protects the surface, a contamination prevention functional layer, an antistatic functional layer, planarization A flattened layer that is flattened after the formation of a transparent layer that is not used or shared (transparent that is not used as a transparent layer), or an adhesive layer that is attached to another substrate such as a display front plate is there. The optical filter function includes a near-infrared absorption function that absorbs near-infrared light, an ultraviolet absorption function that absorbs ultraviolet light, a neon light absorption function that absorbs neon light of a PDP display, and a color correction function that corrects a display image to a desired color tone. Etc.

By the way, in order to develop the near infrared absorption function, a highly transparent near-infrared region such as diimmonium compounds, phthalocyanine compounds, cesium tungsten complex oxide (typically Cs _0.33 WO ₃ ) fine particles, etc. An infrared absorbing dye is added to the predetermined layer. In order to develop the ultraviolet absorbing function, an ultraviolet absorber having high transparency in the visible light region such as a benzotriazole compound, a benzophenone compound, and cerium oxide fine particles is added to a predetermined layer. In order to develop the neon light absorption function, a neon light absorption dye such as a compound having an absorption maximum in the vicinity of a wavelength region of 570 to 605 nm such as a tetraazaporphyrin compound is added. In addition, as the predetermined layer to which these dyes are added, one independent layer may be provided, or a transparent layer such as a primer layer, a transparentizing layer, a transparent base material, or a flattening layer as described above. These layers may be combined with the optical functional layer.

  In addition, each of these layers may be a layer having a plurality of functions. In addition, for each of these layers, conventionally known various layers and layer forming steps may be appropriately employed in an electromagnetic wave shielding material for displays. For example, the dye-added optical filter function is formed by a known coating method as a resin layer in which a near-infrared absorbing dye, a neon light absorbing dye, a color correcting dye, or the like is appropriately dispersed in a resin.

  Further, the present invention will be described with reference to examples and comparative examples. In addition, this invention is not limited to a following example. Further, hereinafter, “part” means “part by mass”.

[Example 1]
An electromagnetic wave shielding material 10 as shown in the sectional view of FIG. 4 was produced as follows.

(Production of intaglio)
As an intaglio plate, a hollow cylindrical iron core surface is coated with a copper plating layer and is made of a metal cylinder. A diamond bite is used to cut the concave portion of the mesh pattern, and the surface is further chrome plated to obtain a line width. A concave portion having a square lattice mesh pattern with a thickness of 20 μm, a line pitch of 300 μm, and a plate depth of 10 μm was prepared.

(Formation of liquid primer layer)
First, as a transparent substrate 11, a biaxially stretched polyethylene terephthalate film having a thickness of 100 μm and a width of 1000 mm, which has been subjected to a single-sided easy-adhesion treatment, is prepared. A primer made of a radiation curable resin was applied by a gravure reverse method to form a uniform liquid primer layer 12 having a thickness of 3.5 μm.
In addition, the said ionizing radiation curable resin mix | blends an epoxy acrylate prepolymer, a urethane acrylate prepolymer, an acrylate monomer, and a photoinitiator, and was prepared as an ultraviolet curable resin composition.

(Intaglio printing of conductive ink and solidification of primer layer)
Subsequently, a conductive ink printing layer was formed on the liquid primer layer 12 by intaglio printing and solidified by UV curing of the primer layer in-line without winding.
That is, after supplying conductive ink to the plate surface of the rotating intaglio plate with a pickup roll, excess ink on the plate surface convex portion other than the concave portion was scraped with a doctor blade, and the conductive ink was filled only in the concave portion.
Subsequently, the plate surface portion after the conductive ink is filled only in the recesses by matching the continuous belt-like transparent base material 11 on which the primer layer 12 is formed with the peripheral speed of the intaglio cylindrical surface rotating. The pressure is applied to the plate surface with a nip roller, and a liquid primer layer is allowed to flow from the surroundings into the depression on the upper surface of the conductive ink filled in the depression on the plate surface, thereby eliminating the gap due to the depression (as a result of the depression Some recesses have a thicker primer layer than others).

  For conductive ink, 93 parts of scaly silver powder with an average particle diameter of about 2 μm as conductive powder was dispersed and adjusted in a resin binder containing 7 parts of a binder resin of thermoplastic polyester resin and 25 parts of solvent butyl cellosolve acetate. A solvent-drying type ink was used.

  Then, the primer layer was cured and solidified by irradiating ultraviolet rays from the ultraviolet lamp disposed around the intaglio plate through the transparent substrate to the intaglio plate rotating with the transparent substrate pressed onto the plate surface. Subsequently, immediately after passing the next nip roller (peeling roller), the transparent base material is separated from the intaglio, and a printing film having the conductive ink printing layer 13 having a predetermined pattern transferred onto the solidified primer layer 12 on the transparent base material 11 is obtained. Then, the solvent of the conductive ink was dried by heating through a drying zone, the ink was solidified, closely fixed to the primer layer, and once wound on a roll.

(Print film)
The thickness of the conductive ink printing layer after drying and solidification (step difference between the primer layer surface of the opening and the top of the conductive ink printing layer) was about 9 μm due to volume shrinkage due to solvent drying.
As a result, a solidified primer layer 12 having a thickness of 3.2 μm (thickness after curing) is formed on the entire surface of one side of the transparent substrate 11 having a thickness of 100 μm (at least the thickness at the opening), and further the primer On the layer 12, it was a conductive mesh printing film in which a conductive ink printing layer 13 having a thickness of about 9 μm was formed in a predetermined mesh-shaped pattern.

The fine line having a line width of 20 μm had no printing failure due to disconnection or shape failure (ink layer missing portion), and the ink transfer rate was good. The transfer rate evaluated by (thickness after curing of ink transferred from plate recess / depth of plate recess) was 9/10. In addition, the thickness of the primer layer immediately below the conductive ink printing layer is also observed to be thicker than the opening, and the depression in the intaglio recess at the time of printing is filled by the flow of the primer layer. It was solved.
However, when the surface of the primer layer in the opening was magnified and observed, there was an uneven shape formed from the convex part of the intaglio plate surface, and the haze was 8.5%.

(Formation of transparent layer)
Next, a transparent layer was formed by a transfer method. The transparent layer was formed as an adhesive layer having a thickness of 25 μm and also serving as a flattening layer. Specifically, a continuous belt-like adhesive film in which a colorless transparent thermoplastic acrylic adhesive layer having a thickness of 25 μm is provided on a separator film made of a transparent polyethylene terephthalate film having a thickness of 38 μm, the adhesive layer having the above-mentioned conductivity Lamination was performed by heating and pressing with a laminator in a direction in contact with the printing surface of the mesh printing film. After this, after cutting into single sheets, pressurize and heat in an autoclave to remove air bubbles in the adhesive layer caused by the steps of the conductive ink print layer, peel off the separator film, and print the conductive ink A transparent layer that also serves as a planarization layer (planarization) was formed in a form that also covers the layer, and an intended electromagnetic shielding material was obtained.

  The refractive index nt of the transparent layer was 1.49 and the difference in refractive index was 0.06, compared to the refractive index np1.55 of the solidified primer layer. The haze increased to 3.8% and the transparency was improved. The electromagnetic shielding performance was satisfactory.

[Example 2]
In Example 1, an electromagnetic wave shielding material was produced in the same manner as in Example 1 except that the formation of the transparent layer was changed to the following content.
Specifically, a curable resin layer obtained by curing an acrylic resin-based ultraviolet curable resin having the same composition as the primer layer serving as the adhesive layer instead of the transparent layer serving as the adhesive layer was used. First, an uncured and liquid coating solution containing an ultraviolet curable resin is directly applied to the printing surface of the conductive mesh printing film so that the thickness becomes 20 μm when applied to a flat surface, and subsequently applied to the coating surface. Laminating a separator film consisting of a transparent polyethylene terephthalate film with a thickness of 38 μm and flattening the unevenness of the coated surface due to the step of the conductive ink printing layer with a laminating roller, and then irradiating an ultraviolet lamp from the separator film side After curing the resin layer, the separator film was peeled off, and a transparent layer that also serves as a flattening layer (flattening) was formed in such a manner as to cover the conductive ink printing layer, thereby obtaining an intended electromagnetic shielding material.

  The refractive index nt of the transparent layer was also 1.55 with respect to the refractive index np 1.55 of the solidified primer layer, and the refractive index difference between these was zero (0.00). The haze increased to 2.2% and the transparency was improved. The electromagnetic shielding performance was satisfactory.

[Comparative Example 1]
In Example 1, the electromagnetic wave shielding material omitting the formation of the transparent layer. As described above, haze is 8.5% and the transparency is poor.

[Example 3]
In Example 2, the same procedure as in Example 2 was used, except that an ultraviolet curable acrylic resin having a refractive index np of 1.41 for the solidified primer layer and a refractive index nt of the transparent layer of 1.60 was used. In addition, an electromagnetic shielding material was manufactured. The refractive index difference between the refractive index np of the primer layer and the refractive index nt of the transparent layer was 0.19. However, the refractive index difference between the primer layer and air was smaller than 0.41, the haze was increased to 6.2%, and the transparency was correspondingly improved. The electromagnetic shielding performance was satisfactory.

Sectional drawing which illustrates the electromagnetic wave shielding material by this invention with the form. Sectional drawing explaining the thickness of the primer layer in a conductive ink printing layer part and an opening part. Sectional drawing which illustrates another form (there is a clearing layer on a printing layer) of the electromagnetic wave shielding material by this invention. Sectional drawing which illustrates another form (flattening transparentization layer) of the electromagnetic wave shielding material by this invention. Sectional drawing which shows notionally an example of conduction | electrical_connection in a ground area | region. Sectional drawing which illustrates another form (metal thin film layer addition) of the electromagnetic wave shielding material by this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram explaining the novel printing method used as the opportunity of this invention, and the conceptual diagram explaining the novel intaglio printing method utilized with the electromagnetic wave shielding material of this invention with the one aspect | mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electromagnetic shielding material 11 Transparent base material 12 Primer layer 13 Conductive ink printing layer 14 Opening part 15 Uneven shape 16 Transparent layer 16a Transparent layer (flattened transparent layer) which also serves as a flattened layer
17 Metal thin film layer 18a Opening area 18b Grounding area 20 Grounding member 21 Protrusion 31 Printed material (transparent substrate)
32 Primer layer 32A Primer layer in liquid state 33 Intaglio 34 Ink 35 Dimple D Step (just before the transparent layer is formed)
d Step (immediately after forming the transparent layer)

Claims (6)

It has a transparent substrate, a primer layer formed on the transparent substrate, and a conductive ink printing layer formed in a predetermined pattern on the primer layer, and the conductive ink printing layer portion of the primer layer An electromagnetic shielding material having a thickness greater than the thickness of the opening that is a non-formed portion of the conductive ink printing layer,
An electromagnetic wave shielding material, wherein the surface of the primer layer in the opening has an uneven shape, and a transparent layer that fills and smoothes the uneven shape covers at least the primer layer in the opening.   The relationship between the refractive index of the primer layer is np, the refractive index of the transparent layer is nt, and the refractive index of air is na, so that these relationships are | np−nt | <| np−na |. The electromagnetic wave shielding material as described.   The electromagnetic wave shielding material according to claim 2, wherein | np−nt | ≦ 0.14.   The electromagnetic wave shielding material according to any one of claims 1 to 3, wherein the transparent layer also serves as a flattening layer that flattens the surface by reducing a level difference between the opening and the conductive ink printing layer. An electromagnetic shielding material having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive ink printing layer formed in a predetermined pattern on the primer layer,
The surface of the primer layer in the opening, which is a non-formation part of the conductive ink printing layer, has a concavo-convex shape formed during printing of the conductive ink printing layer, and a transparent layer that fills and smoothes the concavo-convex shape Is an electromagnetic shielding material covering at least the primer layer in the opening. The electromagnetic wave shielding material according to any one of claims 1 to 5, wherein a gold thin film is further formed on a surface of the pattern made of the conductive ink printing layer.

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