JP5151516B2 - Electromagnetic shielding material - Google Patents

Description

  The present invention is particularly suitable for disposing on the front surface of a display (image display device), and a pattern layer made of a conductive composition having a predetermined conductive pattern represented by a mesh shape is formed via a primer layer. More specifically, the present invention relates to an electromagnetic wave shielding material that prevents generation of whiskers due to scattering of the conductive composition when forming the pattern layer.

At present, as an electromagnetic wave 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 conventional methods (1) to (3) are used. Various methods for forming a patterned layer using a conductive composition have been proposed. Specifically, the conductive ink is used as a conductive composition, and the ink is formed as a pattern layer such as a mesh by a printing method.
In the following, in particular, in the case of pattern formation using a so-called printing method or a similar method, the conductive composition is printed with conductive ink, the pattern formation method is printed (method), and the pattern layer is printed. The layer and the pattern layer made of the conductive composition are also referred to as a conductive ink printing layer, and both are used appropriately.

(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) Electroless plating catalyst ink in which metal fine particles are dispersed in an ultraviolet curable resin is filled in the mesh-shaped concave portion of the intaglio, and the ultraviolet rays are applied on the plate while the transparent base material is pressed onto the intaglio. 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, the mesh pattern obtained by the conventional printing method 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, the conventional method (1) to the conventional method ( 3) Any electromagnetic wave shielding material using the printing method [hereinafter also simply referred to as (1) above] has a fine line with a jagged line (a thin line has a non-smooth broken line shape or a zigzag shape) or a broken line. Such printing defects are likely to occur and are 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 are performance limitations on the fine wires.
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. This is because 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 metal catalyst ink, the ink in the recesses is difficult to move, so that 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, since catalyst ink or conductive ink contains a large amount of ultraviolet light shielding particles made of metal or graphite, it is difficult to sufficiently harden the ink in the intaglio recess, and it is designed when curing is incomplete. 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.
However, as described above, generally, conductive inks and catalyst inks have strong ultraviolet shielding properties, so the ink in the intaglio indentation usually does not completely solidify and often transfers while leaving some fluidity. .

  Further, the printed product has an appearance feature different from that obtained by the conventional printing method in that the thickness of the primer layer immediately below the ink layer is larger than the thickness of other portions. In the conventional printing method in which the ink layer is printed on the surface of the primer layer that has been solidified in advance, it is substantially difficult to form only a portion of the primer layer that is directly under the printing pattern in advance. Even if it is possible, there is no need to print it on top of that, and it is a feature that has not actually existed until now.

FIG. 8 is another conceptual diagram showing the process of the first half of the novel printing method described in FIG. As shown in FIG. 8 (A), a conductive composition 103 is applied as a conductive ink on the intaglio plate 101 and then scraped with a doctor blade 102 to fill the concave portion 104 of the intaglio plate 101 with the conductive composition 103. . At the time of filling, as shown in FIG. 8B, the conductive composition 105 filled in the recess 104 after scraping with the doctor blade 102 has a dent (indentation) 106 in the upper part thereof.
After that, as described with reference to FIG. 7, the recess 106 is formed by adhering a transparent base material having a liquid primer layer formed on one side in advance to the intaglio so as to sandwich the primer layer. Is filled in the recess 106 and filled up.

However, even the electromagnetic shielding material by the novel printing method has a problem to be solved.
The conductive ink using the conductive composition is pulled out from the inside of the intaglio plate, moved away from the intaglio plate, and transferred onto the printed material, except for the portion where the pattern layer of the predetermined pattern of the conductive composition is to be formed. That is, “scattering traces” in which the liquid conductive composition is scattered in the non-formed portion. Since this scattering mark is formed in a roughly beard shape from the thin line of the pattern layer, it will be referred to as “beard” hereinafter.
A beard is a conductive ink printing which is a pattern layer formed by a conductive ink which is a conductive composition, as conceptually shown as a beard 15 in the plan view of FIG. 9A and the cross-sectional view of FIG. 9B. It occurs in the region of the opening 14 that is the non-formed portion of the layer 13. In addition, illustration of the primer layer on the transparent base material 11 is abbreviate | omitted in sectional drawing of FIG.9 (b).

  Against such a technical background, the problem of the present invention is to provide a primer layer in which a conductive ink printing layer, preferably formed by the above novel printing method, is provided on a transparent substrate via a primer layer. It is to provide an electromagnetic wave shielding material that effectively utilizes the unique characteristics of the electromagnetic wave shielding material and prevents the whiskers that are generated when the conductive ink leaves the intaglio when the conductive ink printing layer is formed.

  Accordingly, the inventors of the present application have found the following facts as a result of repeated investigations and studies for solving the above problems. That is, it has been surprisingly found that the cause of the beard is due to a charged electric charge (static electricity) in forming the pattern layer. Initially, since the pattern layer was formed of a conductive composition, it was naturally considered that the antistatic performance was inherent. However, in reality, the pattern layer has a small area ratio, and in the case of an electromagnetic wave shielding material for the front surface of an image display device, the area occupied by the non-formation area of the pattern layer formed of a conductive composition in the total surface area The rate ranges from 90 to 95%. This non-formation region (opening) is composed of a transparent substrate made of an electrical insulator and a primer layer (without adding an antistatic agent). The charge charged on the region of the electrical insulator is low in efficiency of flowing into the pattern layer and removing electricity, apart from those in the vicinity of the pattern layer formed of the conductive composition. Furthermore, although a normal conductive composition exhibits sufficient conductivity (that is, antistatic property) after being completely solidified, the conductive particles are insulated from each other by a solvent or the like in a fluid state. Or due to reasons such as not being in a state of exhibiting electrical conductivity, sufficient electrical conductivity is not exhibited. Therefore, it was proved that the conductive composition in a fluid state was attracted or repelled by the attractive force of the electric charge charged during the formation of the pattern layer, and the above-mentioned beard was generated. And based on this knowledge, this invention forms a desired electroconductive pattern with the pattern formation method represented by printing using the electroconductive composition represented by electroconductive ink, and is as follows. An electromagnetic shielding material having a configuration was used.

(1) having a transparent substrate, a primer layer formed on the transparent substrate, and a pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer, Among them, an electromagnetic wave shielding material in which the thickness of the pattern layer portion is larger than the thickness of the opening which is a non-formation portion of the pattern layer, and the primer layer contains an antistatic agent.

  With this configuration, first, when the conductive composition is patterned by a printing method with a primer layer formed so that the portion immediately below the pattern layer made of the conductive composition is thicker than the opening, the conductive composition ( Prevents pattern formation defects such as fine line burrs and disconnections due to poor transfer of conductive ink, and reduced adhesion between the two layers leading to dropout of the pattern layer made of the conductive composition, and the transfer rate of the conductive composition also The antistatic agent added to the primer layer improves the appearance of whiskers, and even an electromagnetic wave shielding material by a printing method using a conductive composition (conductive ink) becomes a highly practical shielding material.

(2) The electromagnetic wave shielding material according to (1), wherein the interface between the primer layer and the pattern layer made of the conductive composition is alternately arranged.
(3) Alternatively, in the above (1), the primer component contained in the primer layer in the joint region including the two layers of the primer layer and the pattern layer made of the conductive composition, and the conductivity The electromagnetic wave shielding material in which the mixed area | region where the electroconductive composition component contained in the pattern layer which consists of a composition mixes exists.

  Due to the constitution of (2) or (3), when the printing method is used as the pattern forming method, the interlayer adhesion between the primer layer and the pattern layer made of the conductive composition from the release of the conductive composition. Therefore, the transition rate of the conductive composition and the adhesion of the conductive composition are further improved, and the pattern formation (printing) defect can be prevented more reliably, and the high-definition conductive composition can be obtained by a printing method. The pattern layer which consists of can be implement | achieved more reliably.

(1) In the electromagnetic wave shielding material according to the present invention, due to the thickened primer layer immediately below the pattern layer made of the conductive composition, the conductive composition is insufficiently transferred, such as a fine line or a broken wire, and the conductive composition has poor adhesion. Pattern formation failure during pattern formation by the conductive composition can be prevented, the transfer rate of the conductive composition can be improved, whiskers can be suppressed, and a pattern layer made of a high-definition conductive composition can be realized by a printing method. .
(2) The presence of a structure in which the interface between the primer layer and the pattern layer made of the conductive composition is interleaved, and the primer component in the joint region of the primer layer and the pattern layer made of the conductive composition Due to the presence of the mixed region with the conductive composition component, the transfer rate of the conductive composition and the adhesion of the conductive composition are further improved, and pattern formation (printing) defects such as insufficient transfer and poor adhesion are more reliably ensured. The pattern layer which consists of a highly precise conductive composition can be more reliably realized by the printing method.

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

[Explanation of drawings]
The referenced drawings are
FIG. 1 is a cross-sectional view conceptually showing a characteristic cross-sectional shape in one form of an electromagnetic wave shielding material according to the present invention, and a plan view conceptually showing a state in which beard generation is prevented. ,
FIG. 2 is a cross-sectional view conceptually showing an example of a pattern layer made of a conductive composition (form A: interfaces are interleaved),
FIG. 3 is a cross-sectional view conceptually showing an example of a pattern layer made of a conductive composition (form B-1: a mixed region is present near the interface);
FIG. 4 is a sectional view conceptually showing an example of a pattern layer made of a conductive composition (form B-2: a mixed region is present in a conductive ink printing layer);
FIG. 5 is a sectional view showing another embodiment (addition of a metal foil film layer) of the electromagnetic wave shielding material according to the present invention,
FIG. 6 is a cross-sectional view conceptually showing one aspect of a cross-sectional shape of a pattern layer made of a conductive composition,
FIG. 7 is a conceptual diagram illustrating a novel printing method, which is a pattern forming method that can be used when manufacturing the electromagnetic shielding material of the present invention, in one aspect thereof.
FIG. 8 is another conceptual diagram illustrating the first half of a novel printing method which is a pattern forming method that can be used when manufacturing the electromagnetic wave shielding material of the present invention.
FIG. 9 is a plan view (a) and a cross-sectional view (b) conceptually showing a beard.

[Outline by representative composition]
The electromagnetic wave shielding material according to the present invention is basically solidified on a transparent substrate 11 like the electromagnetic wave shielding material 10 of FIG. 1A whose cross-sectional shape schematically illustrates one form in an enlarged cross-sectional view. The primer layer 12 is laminated, and the primer layer 12 has a conductive ink printing layer 13 printed as a pattern layer made of a conductive composition and printed in a predetermined pattern. The thickness Ta of the primer layer 12 in the layer 13 portion (directly below) is thicker than the thickness Tb of the primer layer 12 in the opening 14 and is a portion where the conductive ink printing layer 13 is not printed and is light transmissive. The primer layer 12 in the opening 14 that bears an antistatic agent. As a result, like the electromagnetic wave shielding material 10 shown in the enlarged plan view of FIG. 1B, the opening 14 which is a non-formation portion of the conductive ink printing layer 13 has no beard or is not charged even if it exists. Less than when no agent is contained.

  Note that the transparent resin layer 16 may be formed on the conductive ink printing layer 13 together with the opening 14 as shown in the cross-sectional view of FIG. The structure formed on both the opening and the conductive ink printing layer is preferable in that a transparent resin layer can be easily formed.

[beard]
As conceptually shown in FIG. 9, the beard 15 includes not only those connected to the pattern layer (conductive ink printing layer) 13 but also those separated from the pattern layer. In addition, the planar shape of the mustache extending from the pattern layer is a straight line, a curved line, a bent line, or a shape in which these are combined (a bent curve, a branched shape, etc.), and the shape, size, thickness, length, etc. Is usually not uniform.
And, the electromagnetic wave shielding material according to the present invention suppresses the generation of whiskers, and the primer layer contains an antistatic agent even if there is no whiskers as shown in the plan view conceptually shown in FIG. Compared to the case where it is not. Whiskering occurs when conductive ink scatters during release, which is pulled out of the intaglio recess, but by containing an antistatic agent in the primer layer, the generation of whiskers is suppressed. The cause is considered to be due to peeling electrification when the transparent substrate is separated from the plate.

[Transparent substrate]
The transparent substrate 11 can be a substrate that is transparent at least in the visible region. In consideration of the required physical properties such as light transmittance, heat resistance, mechanical strength, or further ionizing radiation transmittance in the visible region, A known material and thickness may be selected as appropriate, and a transparent inorganic plate such as glass or ceramics or a rigid material such as a resin plate may be used. However, in consideration of suitability for continuous processing by roll-to-roll, which is excellent in productivity, it is flexible. A preferable resin film (or sheet) is preferable. A material satisfying such required performance is usually an electrical insulator.
The roll-to-roll means a processing form in which the material is unwound from a winding (roll), supplied, appropriately processed, and then wound and stored in the winding.
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, polyimide resin and the like. Among these, a biaxially stretched film of polyethylene terephthalate is a preferable transparent substrate in terms of heat resistance, 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.
As described above, a transparent substrate having a heat resistant temperature as high as possible is usually preferable, but a suitable material may be selected from the processing temperature necessary for the production of the electromagnetic shielding material, the cooling method used, the cost, and the like.

In addition, well-known additives, such as a ultraviolet absorber, an infrared absorber, a coloring agent, a filler, a plasticizer, can be suitably added in resin of a transparent base material as needed. Although not essential in the present invention, an antistatic agent is also added to the transparent substrate to further improve the antistatic performance, or a pattern layer formed of a conductive composition. When a sufficient amount of antistatic agent cannot be added to the primer layer due to problems such as adhesion, the antistatic agent effect can be reinforced. The external line absorber is hardened by irradiation with ionizing radiation to solidify the primer layer during conductive ink printing. 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.
In addition, the transparent base material is subjected to known easy adhesion treatment such as corona discharge treatment, easy adhesion primer treatment (including formation of an underlayer) using a material / formation method different from the primer layer 12 unique to the present invention. It may be what you have done. In addition to improving adhesion, the underlayer may have various functions such as durability improvement, print quality improvement, and heat resistance improvement.

[Primer layer]
Although the primer layer 12 is a layer containing an antistatic agent as an essential component, the original main purpose is to improve the ink transfer property from the plate to the printing material when the conductive ink printing layer is formed by printing. It is a layer for improving the ink adhesion with the substrate. 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, as described above, in the primer layer 12, the thickness Ta of the conductive ink print layer portion of the primer layer is larger than the thickness Tb of the opening 14 which is a non-formation portion of the conductive ink print layer.

  Preferably, 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 finally becomes an electromagnetic shielding material. It is formed as a solidified 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.

  The opening of the primer layer may be formed with unevenness that is inevitably generated although it is not desired (this is also referred to as “inevitable unevenness”). Inevitable irregularities are the surface of the intaglio indentations, such as micro cracks on the plating surface when the plate surface is chrome-plated for plate durability, surface roughness, scratches on the doctor blade, and polishing scratches when the plate surface is polished. It is an uneven shape formed at the time of printing formation of the conductive ink print layer due to the uneven shape or the inclusion of dust. Even if it says an uneven | corrugated shape, it is the concave shape dented from the primer layer surface, the convex shape which swelled, and the uneven shape which literally combined the concave and convex. When such an inevitable unevenness causes an undesired decrease in the transparency of the opening, the transparent resin layer 16 may be formed including at least the opening or the conductive ink printing layer.

[Thickness Ta> Tb]
In the present invention, as shown in FIGS. 1 to 5, the thickness Ta of the conductive ink printing layer portion of the primer layer is larger than the thickness Tb of the opening 14 which is a non-formed portion of the conductive ink printing layer. It has the following features. The shape feature can be formed by the novel printing method described with reference to FIG. That is, in the novel intaglio printing method in which printing is performed via a liquid primer layer that is solidified at the time of printing, as described with reference to FIG. 7, the plate surface protrusions are formed on the upper surface of the ink 34 filled in the recesses. Even when a dent 35 that does not become flush (same level surface) is generated, the primer layer 32A that is interposed between the printing medium and the intaglio and is in contact with the intaglio is liquid, so it flows into the dent and fills the gap, thereby forming an ink dent. Improves incomplete contact due to the gap between the printing material 31 and the ink in the part, realizes a more perfect contact state, eliminates defective printing due to insufficient ink transfer, insufficient ink adhesion, etc. Also, ink transfer rate improves.

  Thus, when there is a depression, as shown in FIGS. 1 to 6, 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 (the depth of the depression). Phenomenon) is observed. In addition, when 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.

  Moreover, although the cross-sectional shape of the primer layer which became thick in the conductive ink printed layer portion is a shape where the thickness becomes thicker toward the center in the line width direction of the conductive ink printed layer in FIGS. A so-called bell-shaped shape such as a semi-ellipse or a normal distribution curve, a so-called mountain shape such as a triangle, a trapezoid, or a 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 it is preferable that the primer and the ink are in contact with each other in a liquid state to form a conductive ink printing layer using the ink, the shape of the contact surface essentially includes variation (surface disorder). Therefore, when viewed in the line width direction of the cross section, the possibility that a portion where the thickness of the mountain-like skirt portion of the primer is thinner than the opening thickness Tb partially exists is not zero. However, in such a case, the effect of the present invention is not disturbed.

  1 to 6 exemplify 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. May be anywhere below the conductive ink printing layer, but may be represented by the maximum thickness.

  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. Further, the thickness Ta of the primer layer in the conductive ink printing layer portion is not particularly limited, but is usually about 1/10 to 1/2 of the maximum thickness of the conductive ink printing layer.

  The material used for the primer layer 12 is preferably a material that can be solidified from a liquid state to a solid state on the plate when it is in contact with the plate, except that an antistatic agent is used as an essential material (ink ink). Basically, there is no particular limitation to prevent printing defects such as fine line burrs and disconnections due to transfer defects and ink adhesion deterioration and to improve the ink transfer rate. 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. These various monomers and prepolymers are used alone or in appropriate combination of two or more.

  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.

The antistatic agent may be appropriately selected from known materials and used. An antistatic agent generally indicates a material that can be made into a material having a surface resistivity of 10 ¹¹ [Ω] (also referred to as [Ω / □], [Ω / sq]) or less depending on the use of the antistatic agent. It is a material that has a conductive property that prevents the electrification of the object after the heat. Usually, a material that can be made to have a surface resistivity of about 10 ⁵ to 10 ⁹ [Ω] is used. As the kind of the antistatic agent, a surfactant (for example, anionic or cationic in the ion classification, silicone in the skeleton classification, etc.) can be used. For example, as an anionic surfactant, a lithium salt of a modified silicone is one of the preferable materials from the viewpoint of a beard suppressing effect and being colorless and transparent. Further, as a cationic surfactant, a quaternary ammonium salt is also one of preferable materials from the viewpoint of a beard suppressing effect and being colorless and transparent.
In addition, since it mixes with a primer layer as an antistatic agent, a transparent and colorless thing is preferable and the unintentional coloring as a final electromagnetic wave shielding material can be prevented.
In addition, if the content of the antistatic agent is too small, the whisker suppressing effect cannot be sufficiently obtained, and if it is too much, it becomes wasteful, and for example, about 0.1 to 10% by mass with respect to the resin content in the primer layer. Although it is set as content, what is necessary is just to set to appropriate content according to the beard generation | occurrence | production situation.

  Further, in the primer layer, various additives and modified resins can be further added as necessary for improving adhesion, durability, and imparting various physical properties. What is necessary is just to select a well-known thing suitably as an additive. For example, additives such as plasticizers, surfactants, extender pigments, heat stabilizers, light stabilizers (ultraviolet absorbers, radical scavengers), infrared absorbers, and colorants.

[Formation of primer layer]
Each formation method itself for forming the primer layer or forming the conductive ink printing layer is not particularly limited in the present invention as the electromagnetic wave shielding material, but in the electromagnetic wave shielding material of the present invention, the conductive ink printing is included in the primer layer. Any method or material may be used as long as the shape of the layer portion is greater than the thickness of the opening that is a non-formation portion of the conductive ink print layer.
For example, the primer layer can be formed by applying a primer appropriately using a solvent or the above-described material as a primer component to the transparent substrate by a known coating method. Examples of the coating method include gravure coating, comma coating, die coating, and roll coating.

In order to solidify the primer layer from the liquid state to the solid state on the plate when the primer layer is in contact with the plate, a typical example is a case where a thermoplastic resin is used as the primer to make it liquid by heat softening. As a typical method, a normal temperature solid primer layer is once formed by coating, the solid primer layer is brought into contact with a plate surface filled with a conductive ink, and then the primer layer is heated and softened. Let it be liquid. The coating is performed by applying a solvent-added primer coating solution and then drying the solvent 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. In addition, after the primer is melt-coated, it can be brought into contact with the plate surface 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.
In order to solidify the liquid primer layer in contact with the intaglio, a chemical reaction such as a crosslinking reaction, cooling, or a combination thereof can be used depending on the resin material of the primer.
Above all, ionizing radiation irradiation can complete chemical reaction instantly, so it is suitable for solidification on a cylindrical intaglio that requires high-speed solidification, has excellent productivity, and the corresponding ionizing radiation curable resin also has a primer. It is an excellent solidification method in that it can be handled in liquid form from the application stage.

[Conductive ink printing layer]
The conductive ink printing layer 13 as a pattern layer made of a conductive composition is a layer formed by printing a conductive ink as a conductive composition in a predetermined pattern. Preferably, the new intaglio printing is used for the printing. Use the law. 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.
For display applications, the periphery of the four sides that does not affect the image display is a solid pattern that does not provide an opening for grounding conduction, or a ground area that has a small occupied area ratio even if it exists is an image display area that has an opening. May be provided around.

  Any known conductive ink may be used as appropriate. Typically, the conductive ink is an ink in which conductive powder is dispersed in a resin binder. The resin binder includes a resin and, if necessary, a solvent and other additives. Ink. Moreover, what was implement | achieved by including electroconductive resin and a conductive compound may be sufficient as electroconductivity not using electroconductive powder or using together with this. The conductive ink component is made of these materials.

In addition, binders for conductive ink (components other than conductive powder responsible for conductivity, also referred to as vehicle) may be selected in consideration of printability, conductivity, stability, etc., thermoplastic resins, thermosetting resins, ultraviolet rays Depending on the application from resins such as curable resins, crosslinking agents (curing agents), polymerization initiators, solvents (organic solvents or water), thickeners, surfactants, polymerization inhibitors, stabilizers, various fillers, etc. Can be used in combination. In addition, the binder containing resin is a resin binder.
As the conductive ink, for example, a paste containing a conductive powder such as a commercially available silver paste or copper paste can be used, and a conductive ink containing a so-called nano-sized conductive powder that can be fired at a low temperature is used. You can also

  There is no restriction | limiting in particular about the viscosity of electrically conductive ink, What is necessary is just to select suitably with the printing method and material to be used. In general, when a nano-sized material is used for the conductive powder, the viscosity can be lowered, so ink jet printing, gravure printing, flexographic printing method, etc. are suitable, and the particle size of the conductive powder is about submicron to micron. When particles are used, since the viscosity is generally high, various intaglio printing such as gravure printing, flexographic printing, screen printing, dispenser and the like are suitable. In the present invention, which is a product invention, the printing method, which is a pattern forming method, is not particularly limited. However, the intaglio printing is preferably used, and the intaglio printing is particularly preferred among these printing methods. It is.

  In addition, the conductive ink printing layer is preferably one having conductivity that can exhibit sufficient electromagnetic wave shielding performance immediately after the formation of the printing pattern, but is preferably subjected to electrochemical treatment, chemical treatment, baking treatment, or induction heating. Conductivity may be exhibited by pretreatment such as. These may be combined.

[Conductive powder]
Examples of the conductive powder 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. Ultimately, such as powder coated with metal such as gold or silver with low resistivity metal, graphite or carbon black powder, or material that develops conductivity by chemical reaction, etc. In addition, powders that can provide conductivity to the conductive ink printing layer are used, and known powders can be appropriately employed as these powders.
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. The size of the conductive powder should be small enough to be inked (pasted), and usually a particle size of 100 μm or less is preferable. For example, in the case of flaky silver powder, those having an average particle diameter of 0.1 to 10 μm can be used, and in the case of carbon black powder, those having an average particle diameter 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, resins described in the primer layer and the transparent resin 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. Further, the black pigment or dye may be a mixed system of two or more chromatic colors that are mixed to become black (the chromatic colors are, for example, three primary colors of yellow, red, and blue). The black color referred to here does not have to be a completely achromatic color whose brightness is close to zero. Any low-brightness and low-saturation color in a category that substantially suppresses reflection of extraneous light and does not adversely affect the color reproduction of the image may be used. For example, amber, brown, dark green, rosin (dark red), dark purple Etc. are also included in the black category.

[Various forms of conductive ink printing layer]
2 to 4 are sectional views conceptually showing various forms of the conductive ink print layer, more specifically, various forms about the relationship between the conductive ink print layer and the primer layer. FIG. 2 shows form A in which the interface between the conductive ink printing layer and the primer layer is interleaved. 3 and 4 show that the primer component contained in the primer layer and the conductive ink component contained in the conductive ink printing layer are mixed in the joint region including the two layers of the primer layer and the conductive ink printing layer. Fig. 3 shows form B-1 and Fig. 4 shows form B-2.
In addition, as a form of a conductive ink printing layer, you may have two or more some forms of each form of form A, form B-1, and form B-2.
By these forms, since the interlayer adhesion between the primer layer and the conductive ink printing layer is further improved from the time of the release of printing, the ink transfer rate and the ink adhesion are further improved, the printing defects can be more reliably prevented, A high-definition conductive ink printing layer can be realized more reliably by the printing method.

In Form A and Form B, the adhesion between the primer layer and the conductive ink printing layer due to the thickness of the conductive ink printing layer portion of the primer layer being larger than the thickness of the opening which is a non-formed portion of the conductive ink printing layer In addition to the improvement of the ink transfer rate and the ink transfer rate, the interlaminar adhesion is improved by the throwing effect and the ink transfer rate at the time of printing is improved (almost 100%).
In addition, although the cross-sectional external shape of the conductive ink printing layer 13 of FIGS. 1-5 which is a conceptual diagram is drawn in the substantially trapezoid shape, it is not limited to this, A bell shape etc. are arbitrary.
For example, like the conductive ink printing layer 13 of the electromagnetic wave shielding material illustrated in FIG. 6, even in the shape of a bell, it is formed on the middle part of the protruding portion of the mountain so as to leave the peak of the protruding portion of the primer layer 12 in the outer shape. In addition, even if both the skirt portion of the primer layer 12 and the conductive ink printing layer 13 are included, the bell shape is smooth, and the interface 17 exists in the middle portion of the bell shape.

(Form A)
Form A is a form in which the interface 17 between the primer layer 12 and the conductive ink printing layer 13 is alternately arranged on the primer layer 12 side and the conductive ink printing layer 13 side, as shown in FIG.
The interface 17 may be an interface between the primer layer 12 and the resin or filler constituting the conductive ink printing layer 13. The “filler” is an arbitrary powder, and may be the above-described conductive powder or non-conductive powder. The degree of complicatedness of the interface when the conductive powder is used depends on the shape and size of the conductive powder. In addition, for example, when the conductive ink does not include a filler such as conductive powder, and the conductivity is realized by including a conductive resin or a conductive compound, by the pressure when the primer layer 12 is pressed against the plate, etc. The interface 17 can be in a complicated form.

  Due to the so-called anchoring effect (anchor effect) due to the complicated interface 17 in the form A, it is possible to further improve the interlayer adhesion between the primer layer 12 and the conductive ink printing layer 13 and the ink transfer rate.

(Form B)
As examples of form B, form B-1 shown in FIG. 3 and form B-2 shown in FIG. 4 are shown. Form B is a mixture in which the primer component contained in the primer layer and the conductive ink component contained in the conductive ink printing layer are mixed in the joint region including the two layers of the primer layer and the conductive ink printing layer. This is a form in which a region exists. The expression “congruent region” is because the mixed region exists in one or both of the primer layer and the conductive ink printing layer.

(Form B-1)
As shown in FIG. 3, the form B-1 is localized only in the vicinity of the interface 17 between the primer layer 12 and the conductive ink printing layer 13, and the primer component contained in the primer layer 12 and the conductive ink printing layer 13 This is a form in which a mixed region 18 where the conductive ink component is mixed exists. In addition, the component which mutually entered into the other party area | region mutually was described notionally by the point with a large diameter.
In FIG. 3, the interface 17 is clearly drawn, but in the actual mixed region 18, such an interface 17 does not appear clearly and becomes an unclear and ambiguous interface (see FIG. 3). In FIG. 3, the upper and lower contours are drawn with broken lines, and the hatching in the contour is easy to understand. The mixed region 18 drawn at a point larger than the primer layer is above the interface 17 so as to sandwich the interface 17 vertically. It exists both on the conductive ink printing layer 13 side and on the lower side of the interface 17 (primer layer 12 side). In this case, a primer component (for example, a solvent) in the primer layer 12 and an arbitrary component (for example, a monomer component) in the conductive ink printing layer 13 intrude into both layers and solidify. .

The mixed region 18 may exist only on the upper side or only on the lower side of the interface 17. As the mixing region 18 in the case where it exists only on the upper side of the interface 17, the primer component in the primer layer 12 penetrates into the conductive ink printing layer 13, and any component in the conductive ink printing layer 13 enters the primer layer 12. This is the case where no intrusion occurs. On the other hand, as the mixed region 18 when it exists only below the interface 17, any component in the conductive ink printing layer 13 enters the primer layer 12, and the primer component in the primer layer 12 is conductive ink printing. This is the case where the layer 13 does not enter.
The thickness of the mixed region 18 (the thickness in the vertical direction in FIG. 3) is not particularly limited.

  By the mixed region 18 in the form B-1, the interlayer adhesion between the primer layer 12 and the conductive ink printing layer 13 and the ink transfer rate can be further improved.

(Form B-2)
Form B-2 is a form in which the primer component contained in the primer layer 12 is present in the conductive ink printing layer 13 as shown in FIG. In addition, the primer component which entered the conductive ink printing layer was conceptually described in terms of a large diameter.
FIG. 4 conceptually shows a mode in which the primer component is large near the interface 17 and decreases toward the top of the conductive ink printing layer 13 which is a portion far from the interface (internal hatching). Is drawn at a point larger than the primer layer so that it is easy to understand, and it is drawn so as to become less at the top). However, the present invention is not limited to this embodiment, and the primer component only needs to be present in the conductive ink printing layer 13 anyway. The primer component may penetrate into the conductive ink print layer 13 to the extent that it is detected from the top of the conductive ink print layer 13 or may be detected only in the vicinity of the interface 17.
In the form B-2, when the region where the primer component is present in the conductive ink printing layer 13 is localized only in the vicinity of the interface 17, the mixed region 18 is the interface in the form B-1. This corresponds to a form existing only on the upper side of 17.

  With the primer component present in the conductive ink printing layer 13 in the form B-2, the interlayer adhesion between the primer layer 12 and the conductive ink printing layer 13 and the ink transfer rate can be further improved.

  In addition, in the form B exemplifying the form B-1 and the form B-2, when the primer component in the primer layer 12 penetrates into the conductive ink printing layer 13 during the conductive ink printing, it depends on the primer component, The primer component can gel or semi-solidify the conductive ink or allow the curable component to penetrate. In particular, when a curable resin is used as the resin of the primer component, this effect is generally large. Thereafter, when only the primer layer 12 is cured and then the transparent base material is released from the intaglio and printed, the thickened or semi-cured conductive ink can be transferred with a transfer rate of almost 100%. . In addition, in the case where the primer layer and the conductive ink are simultaneously cured and then released from the printing plate, the adhesive strength between both layers is increased, so that the conductive ink can be transferred with a transfer rate of almost 100%. it can.

(Reason why each form is realized)
The shape characteristic that the thickness of the conductive ink printing layer portion of the primer layer is larger than the thickness of the opening which is a non-formed portion of the conductive ink printing layer is a novel intaglio printing described with reference to FIG. What can be achieved by law is as already explained. And forms, such as form A, form B-1, and form B-2, are realizable by adjustment of the material of a primer layer or a conductive ink printing layer, these solidification / hardening conditions, printing conditions, etc.

Among these, the printing conditions will be further described. As shown in FIG. 7B, the transparent base material 31 provided with the primer as a liquid primer layer 32A is formed on the surface of the primer layer 32A on the conductive ink 34 side. Is brought into contact with the intaglio 33 filled in the recess. At that time, it is preferable that the transparent substrate is pressed against the intaglio from the back side by an impression cylinder (also called a backup roller, a pressure roller, or the like). By this pressure-bonding operation by pressurization, the primer layer 32A flows into the depression 35 [see FIG. 7A] above the conductive ink 34 filled in the intaglio depression, and the depression 35 is efficiently filled.
In the process of completing the printing process including the crimping operation and the subsequent solidification of the primer layer and the conductive ink, for example, the conductive powder contained in the conductive ink 34 is formed between the primer layer 32A and the conductive ink 34. A form in which the interface is complicated or a form in which the primer component contained in the primer layer 32A enters the conductive ink 34 and the mixed region 18 exists in the vicinity of the interface 17 or the like can be obtained.

[Formation of conductive ink printing layer]
As already described, the conductive ink printing layer is preferably formed by a new printing method (new intaglio printing method). That is, a conductive substrate is filled only with a concave portion of an intaglio using a doctor blade or the like, and a transparent substrate on which a primer layer to be liquid is formed on one side is applied with a pressure roller so that the primer layer is in contact with the intaglio. After the primer layer is solidified from a liquid state to a solid state in contact with the primer layer by pressure bonding or the like, the transparent substrate is separated from the intaglio plate to release the plate. Printing may be performed by transferring the ink onto the solidified primer layer.
By the way, even if the conductive ink is liquid or solidified at the time of release, in either case, the thickness Ta of the conductive ink printed layer portion of the primer layer is the thickness of the opening 14 where the conductive ink printed layer is not formed. A geometric feature of greater than Tb occurs. In the case of a liquid, a drying operation, a heating operation, a cooling operation, a chemical reaction operation and the like are appropriately performed and solidified to complete a conductive ink printing layer. The conductive ink may be semi-cured and solidified on the plate and completely cured after release.
When the conductive ink is solidified at the time of release, the conductive ink may be solidified by the same method as the solidification method employed for the primer layer or by a different method. Employing the same method such as ionizing radiation irradiation can simplify the apparatus and process, and adopting a similar chemical reaction is advantageous in terms of adhesion.
However, the scattering of the conductive ink generated at the time of release was pulled out from the intaglio recess when the conductive ink was not yet solidified at the time of release rather than when the conductive ink was already solidified at the time of release. Since the conductive ink is liquid and shows a fluid state, it is much more likely to occur. Even if the conductive ink is already solidified at the time of release, whiskering may occur if the solidification is semi-solidified. If the solidification is completely solidified, there is no problem of whiskering. The problem of easiness of attracting foreign objects still remains.

[Transparent resin layer]
The transparent resin layer 16 is a layer that covers at least the surface of the primer layer 12 in the opening 14, and as a result, has a function as a protective layer that protects the primer layer from scratches and dirt, and is further conductive. The transparent resin layer covering the ink printing layer also has a function as a protective layer for protecting the conductive ink printing layer from scratches and dirt. When these protective layers are final surfaces, they are surface protective layers.
As long as the transparent resin layer can realize the light transmittance of the opening, 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.

〔material〕
The resin used for the transparent resin layer may be appropriately selected in consideration of required physical properties such as adhesion to adjacent layers, coating suitability, transparency, and 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, thermosetting 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 can be appropriately selected from those similar to those described above as examples of the primer layer resin.

  Moreover, various additives can be further added to the transparent resin layer as necessary. What is necessary is just to select a well-known thing suitably as an additive. Examples of the additive include plasticizers, surfactants, antistatic agents, 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. In addition, although it is not essential in the present invention, if an antistatic agent is added to the transparent resin layer, no anti-whiskering effect can be expected when forming a conductive ink printing layer, but charging of the completed electromagnetic shielding material is not possible. It is possible to further improve the prevention performance and further improve the dust adhesion effect during post-processing and storage of the electromagnetic shielding material.

  Note that the refractive index of the transparent resin layer is as small as possible when the difference in refractive index from the refractive index of the adjacent primer layer is 0.30 or less, preferably 0.14 or less, more preferably 0.05 or less. It is desirable to be able to maintain transparency by suppressing interface reflection.

The transparent resin layer 16 may further cover the entire surface including the conductive ink printing layer 13 as shown in FIG. It becomes easy to form a transparent resin layer. The figure shows the case where the surface of the transparent resin layer is a flat surface. The flat surface is ideally a perfect flat surface that completely eliminates the level difference between the surface of the electromagnetic ink shielding material on the side of the conductive ink printing layer and the opening of the conductive ink printing layer. In addition, the level difference is reduced. It may be a surface that does not completely resolve.
When forming a transparent resin layer also on a conductive ink printing layer, this transparent resin layer is good also as an adhesion layer, an adhesive layer, etc. for making it adhere with other layers (for example, optical filter films etc.). In the case of the adhesive layer, a known adhesive such as an acrylic resin may be used.

[Metal thin film layer]
A metal thin film may be further formed on the surface of the pattern composed of the conductive ink printing layer 13, the conductivity of the conductive ink printing layer can be further improved, and the electromagnetic wave shielding property is further improved.
The electromagnetic wave shielding material 10 illustrated in FIG. 5 is an example in which a metal thin film layer 19 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 printed layer or the conductive powder is connected by a metal thin film. It is. 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. Examples of the metal of the metal thin film layer include copper, silver, gold, and aluminum. 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.
In addition, the metal thin film layer is usually formed before the transparent resin layer is formed while the exposure of the conductive ink print layer surface is ensured.
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.

[Other additional layers]
In addition to the above-described layers such as the transparent substrate, primer layer, conductive ink printing layer, transparent resin layer, and metal thin film layer, other layers can be further added as necessary. For example, an optical functional layer that provides an optical filter function (layer), 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, etc. And an adhesive layer for attaching to other substrates such as a display front plate. 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 absorbing function, a neon light absorbing dye such as a compound having an absorption maximum in the vicinity of a wavelength range of 570 to 605 nm such as a tetraazaporphyrin compound is added to a predetermined layer. In addition, as a predetermined layer to which these pigments are added, one independent layer may be provided, or the above-mentioned other layers which are transparent layers such as a primer layer, a transparent resin layer, a transparent substrate, and the like may be optical. It may be combined with the 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.

[Example 1]
An electromagnetic wave shielding material was manufactured using the novel intaglio printing method described in FIG.

(Production of intaglio)
As an intaglio, a hollow cylindrical iron core surface is coated with a copper plating layer and a metal cylindrical cylinder is cut using a diamond tool to cut the concave portion of the mesh pattern, and then the surface is chrome plated. Thus, a concave portion of a square lattice mesh pattern with a line width of 20 μm, a line pitch (line-to-line repetition period) of 300 μm, and a plate depth of 20 μm was produced. Further, the mesh pattern was inclined with respect to the intaglio circumferential direction which is the horizontal direction of the long side of the display, and the bias angle was 45 °.

(Preparation of primer layer in liquid state)
First, as the transparent substrate 11, a biaxially stretched polyethylene terephthalate film having a width of 1000 mm and a thickness of 100 μm and having a single-side easy adhesion treatment and having a thickness of 100 μm was prepared. This transparent substrate is fed out from a roll, and a primer made of an uncured, room-temperature, liquid-free, ultraviolet-curing ionizing radiation curable resin (photo-curable resin composition) is applied to the easily-adhesive treated surface by a gravure reverse method. A uniform liquid primer layer 12 having a thickness of 5 μm was formed.
The ionizing radiation curable resin comprises 35 parts by mass of epoxy acrylate prepolymer, 12 parts by mass of urethane acrylate prepolymer, 53 parts by mass of acrylate monomer (44 parts by mass of monofunctional monomer and 9 parts by mass of trifunctional monomer) and photopolymerization. As an antistatic agent for a total of 103 parts by mass (100 parts by mass of resin) of 3 parts by mass of initiator (Ciba Specialty Chemicals, “Irgacure (registered trademark) 184” 1-hydroxycyclohexyl phenyl ketone) 2 parts by weight of a lithium salt of modified silicone (containing 60% by weight of the above-mentioned substance as an active ingredient in a solution of solvent methyl ethyl ketone, 1.2 parts by weight as the active ingredient blending amount, transparent and colorless, see Table 1) It is prepared as an ultraviolet curable resin composition.

(Intaglio printing of conductive ink and solidification of primer layer)
Next, on the primer layer 12 of the transparent base material 11 on which the liquid primer layer 12 is formed on one side, the conductive ink printing layer is formed and the primer layer is formed inline by the intaglio printing method without being wound up. Solidification by ultraviolet curing was performed. That is, first, after the conductive ink was supplied to the rotating intaglio plate surface with a pick-up roll, excess conductive ink on the plate surface convex portions other than the concave portions was scraped with a doctor blade, and the conductive ink was filled only in the concave portions.
Subsequently, the continuous belt-like transparent base material 11 on which the primer layer 12 is formed is made to coincide with the peripheral speed of the intaglio cylindrical surface where the primer layer 12 faces the intaglio plate surface and the running speed is rotated. The liquid primer layer is supplied from the surroundings to the depression on the upper surface of the conductive ink filled in the plate surface recess by supplying the plate surface portion after the conductive ink is filled only in the recess and pressurizing the plate surface with a nip roller. The gap due to the depression was eliminated by flowing in (as a result, the thickness of the primer layer in the depression having the depression was thicker than the other part).

  The conductive ink contains 93 parts by weight of flaky silver powder having an average particle diameter of about 2 μm as the conductive powder, 7 parts by weight of thermoplastic polyester urethane resin as the binder resin, and 25 parts by weight of butyl carbitol acetate as the solvent. Then, after sufficiently stirring and mixing, a solvent dry ink (silver paste) prepared by kneading with three rolls was used. This conductive ink is an ink that exhibits a fluidized state in which solidification has not yet been completed when the transparent substrate is released.

  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 to solidify the ink, and the ink was solidified and fixed to the primer layer to form a conductive ink printed layer that became a solidified conductive ink, which was once wound on a roll.

(Electromagnetic wave shielding material)
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 19 μm due to volume shrinkage due to solvent drying and the like.
As a result, a solidified primer layer 12 having a thickness of 5 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 layer 12 An electromagnetic wave shielding material was obtained as a printing film on which a conductive ink printing layer 13 having a thickness of 19 μm and a line width of 20 μm was formed in a predetermined mesh pattern.

Moreover, when the cross section of the conductive ink printing layer 13 was observed with a transmission electron microscope (TEM), the thickness of the primer layer immediately below the conductive ink printing layer was larger than the thickness of the opening, and printing The depressions in the intaglio depressions were filled and eliminated by the flow of the primer layer. Further, a structure in which the interface between the conductive ink printing layer and the primer layer was intricately observed was observed, and a mixed region in which the boundary portion was partially familiar (compatible) was confirmed.
Further, when the surface portion of the conductive ink printing layer was subjected to secondary ion mass spectrometry (SIMS analysis), a primer component that was not included in the conductive ink but was included in the primer layer was observed, and part of the primer component was conductive ink. It was confirmed that it entered the print layer.

[Example 2]
In Example 1, the antistatic agent contained in the primer layer is 2 parts by weight of an anionic surfactant different from the lithium salt of the modified silicone of Example 1 (no solvent, the whole amount is an active ingredient. Transparent, but the color is An electromagnetic wave shielding material was obtained in the same manner as in Example 1 except that the color was yellowish brown.

[Example 3]
In Example 1, the antistatic agent contained in the primer layer was 2 parts by mass of a quaternary ammonium salt cationic surfactant (90% by mass of the substance as an active ingredient in a solution of a solvent isopropyl alcohol, An electromagnetic wave shielding material was obtained in the same manner as in Example 1 except that the amount of the active ingredient was 1.8 parts by mass (transparent and colorless in color).

[Comparative Example 1]
In Example 1, an electromagnetic wave shielding material was obtained in the same manner as in Example 1 except that the primer layer did not contain an antistatic agent.

[Performance comparison]
In all the examples, the conductive ink printed layer was free from printing failure due to the disconnection of fine lines, was able to satisfy the electromagnetic shielding performance, and the generation of whiskers was suppressed as compared with Comparative Example 1.
The state of occurrence of beard is summarized in Table 1 together with the content of the antistatic agent for the primer layer in the examples and comparative examples. The state of occurrence of beard is magnified with an optical microscope and visually observed. When there is no or almost no beard, it is excellent (◎), when it is slightly present (○), when it is present, it is slightly good (△). ), And the relative presence was evaluated as poor (×).
As a result, as shown in Table 1, the suppression state of the beard generation was the best from Example 1, Example 1 (good)> Example 3 (slightly good)> Example 2 (slightly good but example 3 Slightly inferior)> worsened in the order of Comparative Example 1 (defect). Further, since the antistatic agent has a yellow-brown color in Example 2, coloring of the electromagnetic shielding material due to coloring of the primer layer can occur, but Examples 1 and 3 are colorless, so there is no concern.

Sectional drawing (a) shown notionally with one form of the electromagnetic wave shielding material by this invention, and the top view (b) which shows notionally the state by which the beard generation was prevented. Sectional drawing which shows notionally the example of a form of a conductive ink printing layer (form A: the interface is interleaving alternately). Sectional drawing which shows notionally the example of a form (form B-1: mixing area | region exists in the interface vicinity) of a conductive ink printing layer. Sectional drawing which shows notionally the example of a form (form B-2: mixed area exists in a conductive ink printing layer) of a conductive ink printing layer. Sectional drawing which shows another form example (metal foil film layer addition) of the electromagnetic wave shielding material by this invention. Sectional drawing which shows notionally one aspect | mode of the cross-sectional shape of a conductive ink printing layer. The conceptual diagram explaining the novel intaglio printing method which can be utilized when manufacturing the electromagnetic wave shielding material of this invention with the one aspect | mode. The another conceptual diagram explaining the first half part of the novel printing method which is a pattern formation method which can be utilized when manufacturing the electromagnetic wave shielding material of this invention. The top view (a) and sectional drawing (b) which show a beard conceptually.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electromagnetic shielding material 11 Transparent base material 12 Primer layer 13 Conductive ink printing layer (pattern layer)
DESCRIPTION OF SYMBOLS 14 Opening part 15 Beard 16 Transparent resin layer 17 Interface 18 Mixed area | region in the interface vicinity 19 Metal foil film layer 31 Printed material (transparent base material)
32 Primer Layer 32A Liquid Primer Layer 33 Intaglio 34 Ink (Conductive Ink)
35 Indentation 101 Intaglio 102 Doctor blade 103 Conductive composition (conductive ink)
104 recessed portion 105 conductive composition filled in the recessed portion leaving the recessed portion 106 recessed (recessed)

Claims (1)

A transparent base material; a primer layer formed on the transparent base material; and a pattern layer made of a conductive composition formed on the primer layer in a predetermined pattern. An electromagnetic wave shielding material having a layer part thickness greater than the thickness of the opening that is a non-formed part of the pattern layer,
The primer layer contains an antistatic agent , and a primer component contained in the primer layer in the combined region including two layers of the primer layer and the pattern layer made of the conductive composition, and the conductive layer The electromagnetic wave shielding material in which the mixed area | region with which the electroconductive composition component contained in the pattern layer which consists of a conductive composition is mixed exists .

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