JP2005259605A - Conductive sheet and its forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thinner-filmed highly accurate antenna pattern, a conductive sheet for a non-contact communication medium, and its forming method wherein using durability such as adhesive strength and aging resistance is superior, and surface resistance value is low, and electric wave efficiency is superior. <P>SOLUTION: This is the conductive sheet for the non-contact communication medium in which on the insulate base material, a pattern layer (a) of which the main component is active energy ray-curable composition is formed, and on the surface of the layer, a conductive thin-filmed layer (b) is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive sheet for a non-contact communication medium, and more specifically, a high-precision antenna pattern used for an antenna of a non-contact communication medium such as an IC card, an IC tag, and a wireless IC tag, an adhesive strength and The present invention relates to a thin conductive sheet having excellent durability such as aging resistance, low surface resistance, and excellent radio wave efficiency, and a method for forming the same.

  Conventionally, an antenna of a non-contact communication medium containing an IC chip has a winding method in which a conductive wire such as copper or aluminum wire is wound in a predetermined shape, an etching method in which a conductive layer made of a metal foil formed on a substrate is etched, and It is formed by a printing method that prints in a predetermined shape using conductive ink. However, the above-described winding method is difficult to automate production, and the windings overlap, so that the antenna cannot be thinned. Further, in the etching method, since the conductive layer is etched with the etching solution, the processing of the etching waste solution after the etching becomes a problem. In particular, the treatment of waste liquids containing heavy metals requires consideration for the environment. The printing method is expensive because the conductive ink uses precious metal as the conductive material, and since the conductive material is dispersed in the resin, a sufficient conductive effect cannot be obtained. Environmental burden due to volatilization of solvents.

  In addition to the above methods, there is a method of heat-pressure transfer to an insulating base material by hot stamping using a transfer foil formed by vacuum deposition of metal, but heat-pressure transfer is used for an insulating base material. Since the plastic film is thermally deteriorated or deformed, the pattern shape is also unusual, and it is difficult to form an elaborate antenna pattern. Further, in this method, since the adhesive strength of the antenna pattern cannot be obtained sufficiently, the formed antenna pattern is detached from the base material due to friction or the like in long-term use.

  In addition to the above method, a non-contact IC module antenna forming method (Patent Document 1) has been proposed. However, in the method according to Patent Document 1, the adhesive applied to the holding base is applied with a soft adhesive having a certain thickness to absorb the unevenness of the holding base. However, when a solvent-type adhesive is used, it is difficult to control the thickness of the adhesive due to the dilution ratio of the solvent, evaporation of the solvent, and the like, and it is difficult to apply a constant thickness. Generally, since the adhesive is intended for adhesion, precise pattern formation is inferior. Further, if the thickness of the holding substrate is increased in order to absorb the unevenness of the holding substrate, there is a problem that the pattern becomes thick due to the sagging of the adhesive. Furthermore, as the line width of the antenna pattern becomes narrower, the physical strength such as the adhesive force between the adhesive and the base material and the adhesive and the conductive metal film decreases. For this reason, the antenna pattern formed by adhesion tends to drop off from the base material due to friction or the like, and the line width of the antenna pattern is limited due to durability, and it is difficult to obtain a desired antenna pattern. In addition, the above-described forming method requires that the holding substrate and the transfer film are bonded together, and after the adhesive is cured, the transfer film is peeled off to transfer the metal vapor deposition layer to the holding substrate. Depending on the type, the holding substrate and the transfer film must be wound up at the same time, and then the transfer film must be peeled off, resulting in decreased productivity.

  Moreover, the antenna pattern formed using the transfer foil manufactured by vapor-depositing a general metal has various thicknesses of the vapor-deposited layer, and the surface resistance value is not constant depending on the thickness of the metal film layer. In particular, when the thickness of the metal film layer is too thin, the surface resistance value of the thin film layer increases, and when they are used as antennas for non-contact communication media, the current becomes weak and radio waves can be transmitted efficiently. Can not. As described above, a highly accurate antenna pattern can be formed, and the formed antenna pattern is excellent in durability such as adhesive strength and aging resistance, and has a low surface resistance value and excellent radio wave efficiency. No antennas and methods of forming them are provided.

JP 2001-34732 A

  Accordingly, the object of the present invention is to provide a highly accurate antenna pattern with a thinner film, excellent use durability such as adhesive strength and aging resistance, and low contact resistance with low surface resistance and excellent radio wave efficiency. It is providing the electroconductive sheet for media, and its formation method.

  The above object is achieved by the present invention described below. That is, the present invention is characterized in that a pattern layer (a) mainly composed of an active energy ray-curable composition is formed on an insulating substrate and a conductive thin film layer (b) is formed on the upper layer of the layer. An electrically conductive sheet for a non-contact communication medium and a method for forming the same are provided.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has used the above-described conductive sheet, such as a high-accuracy antenna pattern, adhesive strength, and aging resistance compared to conventional antennas for non-contact communication media. It is a conductive sheet that has excellent durability, low surface resistance, excellent radio wave efficiency, and can be used as a thinner contactless communication medium antenna. It has been found that this is a forming method capable of efficiently and economically mass-producing the conductive sheets used in the production.

  According to the present invention, a high-precision antenna pattern is formed by sequentially forming a pattern layer mainly composed of a specific active energy ray-curable composition on an insulating substrate and a conductive thin film layer on the insulating layer by a specific method. And a conductive sheet that is excellent in durability such as adhesive strength and aging resistance, has a low surface resistance value and excellent radio wave efficiency, and can be used for an antenna for a contactless communication medium with a thinner film. .

  Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention. The conductive sheet that mainly characterizes the present invention is one in which a pattern layer (a) and a conductive thin film layer (b) mainly composed of an active energy ray-curable composition are formed on an insulating substrate. The active energy ray-curable composition constituting the pattern layer (a) has a fine pattern drawing aptitude for forming an antenna pattern, adhesion between the insulating base material and the conductive thin film layer (b), and durability for use. It is excellent. Moreover, electroconductivity can be provided as needed and the electroconductivity of an electroconductive thin film layer (b) can be improved.

  The active energy ray-curable composition for forming the pattern layer (a) is photopolymerizable by irradiating electromagnetic waves such as microwaves, infrared rays, visible light, ultraviolet rays, X rays, and γ rays as active energy rays. Examples thereof include resins obtained by curing a component comprising a monomer, an oligomer, a polymer, and a photopolymerization initiator, preferably curable resins using ultraviolet rays or electron beams. In particular, a cationic polymerization type photo-curing resin is preferable.

  The above-mentioned cationic polymerization photocurable resin is obtained by curing mainly by irradiating with ultraviolet rays or electron beams having a photocationic polymerizable compound and a photocationic polymerization initiator as main components. Examples of the above-mentioned photocationically polymerizable compound include monomers, oligomers and polymers having a photocationically polymerizable epoxy group, vinyl ether group, hydroxyl group, episulfide group, octacene group, and ethyleneimine group in the molecule, and acrylic groups having these functional groups. A photo-cationic polymerizable compound having an epoxy group is preferable, such as a polymer, a polyester polymer, a urethane polymer, a polyether polymer, a polyolefin polymer, a silicone polymer, or a block copolymer rubber.

  Examples of the photo-cationic polymerizable compound having an epoxy group include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; phenol novolac type epoxy resin, cresol novolac type epoxy resin; Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) alicyclic epoxy resins such as adipate; aromatic epoxy resins such as trisphenolmethane triglycidyl ether; 1,4-butanediol Aliphatic epoxy resins such as glycidyl ether and triglycidyl ether of glycerin; glycidyl ester type epoxy resins such as diglycidyl phthalate and hexahydrophthalic acid diglycidyl ester; glycidyl amine type epoxy resins; glycidyl (meth) acrylate and (meta ) A copolymer with a radical polymerizable monomer such as an acrylate ester, preferably an alicyclic epoxy resin.

  Examples of the above-mentioned photocationic polymerization initiator include onium salts such as aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, triphenylphosphonium salts, triallylsulfonium salts; iron-allene complexes, Organometallic complexes such as titanocene complexes; ionic photoacid generation types such as metallocene salts, and nonionic photoacid generation types such as nitrobenzyl esters, sulfonic acid derivatives, phosphate esters, diazonaphthoquinones, etc. .

  The amount of the above cationic photopolymerization initiator is 1 to 5% by mass, preferably 1 to 2.5% by mass, based on the above cationic photopolymerizable compound. When the proportion of the photocationic polymerization initiator is too large, the reaction curing rate is accelerated, while when too small, the reaction curing rate is decreased. In addition, the reaction can be adjusted by adding a compound having a basic functional group such as an amino group, a polyester polyol, or the like as a polymerization adjusting agent to the above-mentioned photo-cationic polymerizable compound.

  Moreover, as said active energy ray hardening composition, the ultraviolet curable resin which has an acrylic monomer and an acrylic oligomer as a main component other than said cationic polymerization type photocurable resin is mentioned. Examples of the oligomer component include epoxy acrylates such as bisphenol A diglycidyl acrylate, epoxidized drying oil acrylate, modified bisphenol A epoxy acrylate, aliphatic epoxy acrylate, and novolak epoxy acrylate; hydroxyls such as diisocyanate and hydroxyl group-containing acrylate Polyurethane acrylates such as reaction products of group-containing materials: Polyol acrylates such as pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate; Such as polyester acrylate; other alkyd acrylate, poly And ether acrylates and mixtures thereof.

  Examples of the photopolymerization monomer include monoacrylates such as hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 6,6-hexanediol monoacrylate, and cyclohexyl acrylate; 1,6-hexanediol diacrylate , Dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, ethylene glycol diacrylate, trimethylolpropane diacrylate, and the like; trimethylolpropane triacrylate, pentaerythritol And triacrylates such as triacrylate and mixtures thereof.

  Examples of the photopolymerization initiator include benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-bidoxycyclohexyl phenyl ketone, 2-hydroxy-2-dimethoxy-1-phenylpropan-1-one. And known photopolymerization initiators such as triallylsulfonium salt.

  Moreover, as the raw material of the electron beam curable resin, the cationic polymerizable compound and methacrylate oligomers and monomers can be used, and maleic acid, itaconic acid, acrylamide, styrene, vinyl toluene, vinyl acetate, Monomers such as acrylic acid and methacrylic acid can be used in combination. If necessary, additives such as extender pigments, surface conditioners and sagging inhibitors are added and used.

  The components of the active energy ray curable composition are inferior in drawability as they are, and when the viscosity is increased and the pattern layer is thickened, sagging occurs and the pattern becomes thicker, or curing by ultraviolet ray or electron beam irradiation. Along with this, there is volume shrinkage of the resin, and the pattern becomes thin. Moreover, if volume shrinkage becomes large, adhesiveness will also fall. Thus, the drawing aptitude at the time of antenna pattern formation is narrow, and the drawing aptitude is inferior, for example, an elaborate pattern cannot be obtained. For this reason, in order to obtain an elaborate pattern, additives such as extender pigments, surface conditioners, sagging inhibitors, and adhesion-imparting agents, and active energy ray-curable compositions are added to the raw material components as necessary. It adjusts the addition amount of the said oligomer and monomer to comprise, and prepares it as a drawing composition. The amount of the monomer added to the oligomer is preferably 60 to 80% by mass. The thickness of the pattern layer (solidified thickness) is 0.5 μm to 8.0 μm, preferably 1.0 μm to 3.0 μm.

  Moreover, the pattern layer which consists of said active energy ray hardening composition can be used alone, However In the range which does not interfere with the objective of this invention, an adhesion | attachment imparting agent can be further added. The adhesion-imparting agent is used for the purpose of improving the initial adhesion and adhesion between the insulating substrate and the conductive thin film, and the blending amount is 10 to 20% by mass with respect to the active energy ray-curable composition. It is. When the amount of the above-mentioned adhesion-imparting agent is too large, the drawing ability of the antenna pattern is lowered, and an elaborate antenna pattern cannot be obtained. Examples of the adhesion-imparting agent include rosin acrylate, rosin resin, rosin ester resin, and saturated hydrocarbon resin.

  Further, the pattern layer containing the active energy ray-curable composition as a main component, if necessary, is compatible with the above composition in order to further improve pattern formation within a range that does not interfere with the object of the present invention. It can be prepared by adding additives such as reactive resins, extender pigments, surface conditioners and sagging inhibitors. As the above resins, for example, resins used in known inks such as vinyl chloride / vinyl acetate copolymers, acrylic resins, polyester resins, petroleum resins and the like can be used.

  In addition, an inorganic conductor and / or an organic conductor can be further added to the pattern layer forming material for the purpose of improving the conductivity of the conductive thin film layer. The blending amount is not particularly limited as long as it does not interfere with the object of the present invention. Examples of the inorganic conductor include fine particles of known metals and oxides thereof, for example, noble metals such as gold, silver, ruthenium, palladium, osmium, iridium and platinum, metals such as copper and nickel, oxidation Examples thereof include metal oxides such as tin and indium oxide, and those doped with antimony or the like. Examples of the organic conductor include carbon black, 7,7,8,8, -tetracyanoquinodimethane complex, conductive polymers such as polyacetylene and polypyrrole, and the like. The conductor is used as a colloidal particle, a solid powder or the like dispersed in the active energy ray curable composition.

  Examples of the conductive thin film layer (b) include metals such as aluminum, copper, silver, gold, nickel, chromium, tin, indium, ruthenium, palladium, osmium, platinum, tin oxide, indium oxide, Thin films such as single layers composed of simple substances such as metal oxides such as indium tin oxide and zinc oxide, and multilayers composed of these composites, preferably aluminum, copper, silver, gold, nickel, chromium, tin, indium, oxidation Examples thereof include a single layer composed of a simple substance of tin, indium oxide, indium tin oxide, and zinc oxide, and a multilayer thin film composed of a composite thereof. The conductive thin film may be a polypropylene film or a plastic film such as a polyester film having a releasability by the known vacuum deposition method, sputtering method, ion plating method or electron beam deposition method, preferably a polypropylene film. As a thin film layer, it is supplied to a plastic film that transmits both visible light and ultraviolet light. The film thickness of the conductive thin film is 0.01 to 1.0 μm, preferably 0.4 to 0.6 μm. If the film thickness exceeds the above upper limit, the conductive thin film is likely to crack due to bending or the like, and the antenna circuit is disconnected. On the other hand, when the film thickness is less than the lower limit, sufficient conductivity and radio wave effect cannot be obtained.

  The total thickness of the conductive sheet of the present invention formed from the active energy ray-curable composition and the conductive thin film is 6 μm or less, and the surface resistance value is 0.1Ω or less. If the total thickness of the conductive sheet is too thick, the antenna circuit cannot be thinned or bent, and if the surface resistance is too high, the radio wave efficiency is lowered.

  Examples of the insulating base material used in the present invention include plastics such as polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride, polyolefin, polyether sulfone, polycarbonate, triacetyl cellulose, nylon, polysulfone, polyacryl, and polyarylate. In addition to films and sheets, insulating substrates such as epoxy and bakelite, and preferably films and sheets such as polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride film.

The conductive sheet is formed by using the drawing composition described above, the following (1), (2), (3) and (4), etc., preferably (1) and (2 ).
The forming method of (1) is first a step 1 of forming a pattern layer from a drawing composition containing a photocationically polymerizable compound as a main component on an insulating substrate, and a step 2 of irradiating the pattern layer with active energy rays. A transfer film having a conductive thin film layer on the base film is bonded to the pattern layer to transfer the conductive thin film layer; a step of peeling the base film; and the pattern layer is completely cured. A step of forming the conductive sheet.

  Moreover, the formation method of (2) is as follows. First, a pattern layer is formed from a drawing composition containing a photocationically polymerizable compound as a main component on the surface of a conductive thin film layer of a transfer film having a conductive thin film layer on a base film. Step 1 for forming, Step 2 for irradiating the pattern layer with active energy rays, Step 3 for pressure-bonding the pattern layer to an insulating substrate to transfer the pattern layer and the conductive thin film layer, and peeling the substrate film This is a method for forming a conductive sheet, which includes step 4 of performing and step 5 of aging and completely curing the pattern layer.

  The pattern layer formation in the first step in the formation method of (1) is, for example, flexographic printing, offset printing, gravure printing, ink jet printing, etc., preferably prepared by flexographic printing with the photocationically polymerizable compound as a main component. Using the drawn composition, the pattern layer is printed on an insulating substrate such as a polyester film to a thickness (solidified thickness) of 0.5 to 8.0 μm. In the second step, the formed pattern layer is irradiated with ultraviolet rays or an electron beam using a high pressure mercury lamp, a halogen lamp, a xenon lamp, a flash UV lamp, an argon glow lamp or the like as a light source. Although irradiation time is not specifically limited, it irradiates to such an extent that a photocationic polymerizable compound is semi-hardened and a conductive thin film layer is crimped | bonded. In the third step, the roll-shaped transfer film having the conductive thin film layer is continuously pressure-bonded to the formed pattern layer with a rubber roll or the like. In step 4, the above film is continuously wound up and removed. In the fifth step, the formed conductive sheet is left to age and the pattern is completely cured.

  In addition, (1) above is the same as the method (2) except that a pattern layer is formed on the surface of the conductive thin film layer of the transfer film having the conductive thin film layer in the method (2). This is the same as the forming method.

  Moreover, the formation method of (3) is the process 1 which forms a pattern layer from the drawing composition which has active energy ray hardening compositions other than a photocationic polymerizable compound as a main component on an insulation base material, and on a base film Step 2 for pressure-bonding a transfer film having a conductive thin film layer to the pattern layer, Step 3 for transferring the conductive thin film layer by irradiating the pattern layer with active energy rays to completely cure the drawing composition, and It is the formation method of the electroconductive sheet including the process 4 which peels a base film.

  Moreover, the formation method of (4) is drawing which has active energy ray hardening compositions other than a photocationic polymerizable compound as a main component on the electroconductive thin film layer surface of the transfer film which has an electroconductive thin film layer on a base film. Step 1 for forming a pattern layer from the composition, Step 2 for pressure-bonding the pattern layer to an insulating substrate, and irradiating the pattern layer with an active energy ray to completely cure the drawing composition to make the pattern layer conductive It is the formation method of the electroconductive sheet including the process 3 which transfers a thin film layer, and the process 4 which peels the said base film.

  As described above, when using a drawing composition containing a photocationically polymerizable compound as a main component for forming the pattern layer, it is related to whether or not the active energy ray is permeable to the transfer film having the conductive thin film layer. The writing composition cures without. However, when an active energy ray-curable composition other than the photocationically polymerizable compound is used as the drawing composition, the active energy rays other than the electron beam do not pass through the conductive thin film layer, so that the pattern layer was formed. The drawing composition is cured by irradiating active energy rays from the back surface of the polyester of the transparent insulating substrate. Note that this is not the case in the case of a transfer film having a conductive thin film layer having transparency.

  As a pattern layer drawing method in the conductive sheet forming methods (1) to (4) described above, gravure printing method, silk printing method, letterpress printing method, inkjet printing method, offset printing method, flexographic printing method, stencil printing plate A drawing method such as a printing method, preferably a flexographic printing method, is particularly preferably used in view of the thickness of the obtained conductive sheet, the pattern layer formability, the formability of the conductive thin film layer on the pattern layer, and the like. In particular, a pattern layer drawing method by an inline flexographic printing process using a flexographic printing method is preferably used.

  The in-line flexographic printing process includes a known rotary flexographic printing machine with an active energy ray irradiation device, a drawing composition supply tank that is cured by active energy, a transfer film supply device having a conductive thin film layer, and the insulation. Laminating roll for press-fitting a transfer film having a pattern layer and a conductive thin film layer flexographically printed on the equipment, and a peeling roll for continuously winding up and removing the transfer film other than the conductive thin film layer in close contact with the upper part of the pattern layer A conductive sheet is continuously formed using a printing machine (not shown) equipped with the above.

  FIG. 1 shows an example of a method for forming a conductive sheet using the above inline flexographic printing process. In the above process, first, a drawing composition mainly composed of a cationically polymerizable compound in the drawing composition supply tank 2 is supplied from the ink roll 3 to the printing cylinder 4 on the insulating substrate 1, and is marked by the impression cylinder 5. The pattern layer 6 is formed on the insulating base material while adjusting the pressure. Next, the ultraviolet irradiation device 7 irradiates ultraviolet rays, and then the transfer film 9 having the conductive thin film layer is sent out from the transfer film supply device 8 having the conductive thin film layer. Crimp the transfer film. Next, the transfer film is wound up and removed immediately leaving the conductive thin film layer in close contact with the upper layer portion of the pattern layer with the peeling roll 11 to form the conductive sheet 12.

  The conductive sheet of the present invention as described above is useful as an antenna for non-contact communication media such as an IC tag and an IC card incorporating an IC chip, and in particular, using a plastic film insulating substrate such as a flexible polyester film. The formed conductive sheet is effective as an IC tag antenna. Further, the conductive sheet of the present invention can be preferably used as a non-contact IC tag or an IC card, particularly as a non-contact IC tag, by being loaded in a non-contact IC module.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “parts” and “%” are based on mass unless otherwise specified. In addition, this invention is not limited to the following Example.

[Example 1]
Using the drawing composition a for forming a cationic polymerization photocured resin, first, using a flexographic printing machine on a 45 μm polyester film, the width is 1.0 mm, the interval is 0.4 mm, and the thickness is 3 μm (dry thickness). The pattern layer was formed by continuous printing. Immediately after printing, the pattern printed surface was irradiated with an integrated light amount of 30 mJ / cm ² using a high-pressure mercury lamp. Next, the transfer film (the base film is a 20 μm polypropylene film) having a conductive thin film layer made of metal copper of 0.5 μm was pressure bonded by passing a rubber laminate roll through the pattern printing surface. After the pressure bonding, the transfer film was peeled off while leaving the conductive thin film layer that was pressure-transferred to the pattern layer, and the formed conductive sheet was left to age and completely cured to prepare a conductive sheet V1 of the present invention.

[Example 2]
A pattern layer is printed and formed on the transfer film having the conductive thin film layer in Example 1 using the drawing composition a in the same manner as in Example 1, and then the pattern layer surface and a 45 μm polyester film are pressure-bonded. Prepared a conductive sheet V2 of the present invention in the same manner as in Example 1.

[Examples 3 to 6]
Conductive sheets V3 to V6 were prepared using the drawing composition b, c, or d. (Example 3)
First, a pattern layer having a width of 1.0 mm, an interval of 0.4 mm, and a thickness of 3 μm (dry thickness) was formed by continuous printing on a 45 μm polyester film using the drawing composition b. Immediately after printing, a transfer film having a transparent conductive thin film layer made of indium tin oxide of 0.5 μm was pressed on the printed surface by passing it through a rubber-made laminate roll. Next, the integrated light quantity 30mJ / cm < ² > was irradiated from the film surface of the transfer film using the high pressure mercury lamp. Immediately after the irradiation, the transfer film was peeled off leaving the conductive thin film layer pressure-bonded to the pattern layer to prepare a conductive sheet V3 of the present invention.

Example 4
In Example 3, the drawing composition c was used as the drawing composition, the same transfer film as used in Example 1 was used as the transfer film, and a high-pressure mercury lamp was irradiated from the back of the printed polyester film. Prepared a conductive sheet V4 of the present invention in the same manner as in Example 3.

(Example 5)
Example 3 with the exception of using drawing composition d as the drawing composition in Example 3, using the same transfer film as the transfer film used in Example 1, and irradiating an electron beam instead of the high-pressure mercury lamp. Similarly, a conductive sheet V5 of the present invention was prepared.

(Example 6)
In Example 4, the conductive sheet V6 of the present invention was prepared in the same manner as in Example 4 except that the pattern layer was printed on the transfer film using the drawing composition c, and pressure-bonded to the insulating substrate.

In addition, said drawing composition a, b, c, and d is as follows.
-Composition a:
Alicyclic epoxy resin 80 parts Polyester polyol 18 parts Triallylsulfonium salt 2 parts Composition b:
20 parts urethane acrylate 20 parts 1,6-hexanediol diacrylate 58 parts 2,2-dimethoxy-2-phenylacetophenone
2 parts

-Composition c:
20 parts urethane acrylate 20 parts mixture of rosin resin and saturated hydrocarbon resin 58 parts dipropylene glycol diacrylate 2 parts 2-hydroxy-2-dimethoxy-1-phenylpropan-1-one 2 parts composition d:
20 parts of urethane acrylate Tricyclodecane dimethanol diacrylate
80 copies

[Comparative Example 1]
Using a known solvent-type metal adhesive, an antenna pattern having a width of 1.0 mm, an interval of 0.4 mm, and a thickness of 10 μm (dry thickness) is printed on a 45 μm polyester film by a silk screen printing method. After evaporation, a commercially available aluminum-deposited transfer film was pressure-bonded. After the adhesive was dried and solidified, the transfer film was peeled off to prepare a conductive sheet S1 of a comparative example.

Each of the above conductive sheets was evaluated by the following measuring method with respect to the surface resistance value, the antenna pattern formation state, the adhesive strength, and the change over time. The evaluation results are shown in Table 1.
(Surface resistance value)
The surface resistance value of each conductive sheet obtained as described above was measured using LORESTA MCR-T350 manufactured by Mitsubishi Chemical Corporation.

(Adhesive strength)
A commercially available cello tape (registered trademark) was affixed to the surface of each of the conductive sheets obtained above, and after standing for 30 minutes, it was peeled off rapidly at an angle of 45 degrees, and the peeled state was visually evaluated.
Evaluation criteria:
A: No separation from the insulating substrate is observed.
X: Peeling from the insulating substrate is partially recognized.

(Pattern formability)
The antenna pattern formability of each conductive sheet obtained above was evaluated by the following method with the following criteria.
Evaluation criteria:
A: There is a pattern reproducibility of the antenna pattern.
X: The thickness of the antenna pattern and the linear portion of the edge of the pattern are not constant and there is no pattern reproducibility.

(Aging resistance)
Each of the conductive sheets obtained above was left in an atmosphere of 40 ° C. and 90% humidity for 3 months, and the subsequent conductive sheets were examined for adhesive strength in the same manner as in the method for evaluating adhesive strength. . And the time-dependent change of the electroconductive sheet on an insulating base material was evaluated on the following reference | standard.
Evaluation criteria:
(Double-circle): The change of the adhesive strength with respect to an insulating base material is not recognized compared with before leaving.
X: Significant decrease in adhesion strength to the insulating substrate is observed compared to before leaving.

  From the physical property results in Table 1 above, it has been demonstrated that a conductive sheet having a low surface resistance value and excellent adhesion strength, antenna pattern formability, and resistance to aging with respect to an insulating substrate can be formed.

  According to the present invention, the conductive sheet of the present invention has an extremely thin and highly accurate antenna pattern, excellent aging resistance and adhesive strength, and has a low surface resistance value. It can be effectively used as an antenna for a contact communication medium. Further, since the method for forming the conductive sheet is suitable for efficient continuous productivity, an antenna for mass production is economically supplied.

The figure explaining the formation method of the electroconductive sheet for non-contact communication media of the present invention.

Explanation of symbols

1: insulating base material 2: drawing composition supply tank 3: ink roll 4: stamping cylinder 5: impression cylinder 6: pattern layer 7: ultraviolet irradiation device 8: transfer film supply device 9 having a conductive thin film layer: conductive thin film Transfer film 10 having a layer: Laminate roll 11: Release roll 12: Conductive sheet

Claims (17)

  A non-contact communication medium characterized in that a pattern layer (a) mainly composed of an active energy ray-curable composition is formed on an insulating substrate and a conductive thin film layer (b) is formed on the upper layer of the layer. Conductive sheet.   The conductive sheet according to claim 1, wherein the surface resistance value is 0.1Ω or less.   The conductive sheet according to claim 1, wherein the active energy ray curable composition is a cationic polymerization photocurable resin.   The conductive sheet according to claim 1, wherein the pattern layer (a) has a thickness of 0.5 to 8 μm.   The conductive sheet according to claim 1, wherein the pattern layer (a) further contains an adhesion-imparting agent.   The conductive sheet according to any one of claims 1 to 5, wherein the pattern layer (a) further contains an inorganic conductor and / or an organic conductor.   The conductive sheet according to claim 1, wherein the conductive thin film layer (b) has a thickness of 0.01 to 1.0 μm.   The conductive sheet according to claim 1 or 7, wherein the conductive thin film layer (b) is a single layer composed of at least one of a conductive metal and / or an oxide thereof, or a laminated multilayer body thereof.   The conductive thin film layer (b) is a single layer made of at least one selected from the group consisting of aluminum, copper, silver, gold, nickel, chromium, tin oxide, indium oxide, indium tin oxide and zinc oxide, or The conductive sheet according to any one of claims 1 and 7 to 8, which is a multilayer multilayer body thereof.   The conductive sheet according to claim 1, wherein a total thickness of the pattern layer (a) and the conductive thin film layer (b) is 6 μm or less.   It is an antenna for non-contact IC tags, The electroconductive sheet of any one of Claims 1-10.   A non-contact IC tag loaded with the conductive sheet according to claim 11.   Step 1 of forming a pattern layer from a drawing composition containing a photocationically polymerizable compound as a main component on an insulating substrate, Step 2 of irradiating the pattern layer with active energy rays, and a conductive thin film layer on the substrate film A step 3 for transferring the conductive thin film layer by pressure-bonding the transfer film having the above structure to the pattern layer, a step 4 for peeling the base film, and a step 5 for fully curing the pattern layer. A method for forming a conductive sheet.   Step 1 of forming a pattern layer from a drawing composition containing a photocationically polymerizable compound as a main component on the surface of the conductive thin film layer of the transfer film having the conductive thin film layer on the base film, and active energy in the pattern layer Step 2 for irradiating the wire, Step 3 for pressure-bonding the pattern layer to the insulating base material to transfer the pattern layer and the conductive thin film layer, Step 4 for peeling the base material film, and complete curing of the pattern layer And a step 5 of forming the conductive sheet.   Step 1 of forming a pattern layer from a drawing composition mainly composed of an active energy ray-curable composition other than a photocationically polymerizable compound on an insulating substrate, and a transfer film having a conductive thin film layer on the substrate film Step 2 for pressure bonding to the pattern layer, Step 3 for irradiating the pattern layer with active energy rays to completely cure the drawing composition to transfer the conductive thin film layer, and Step 4 for peeling the substrate film A method for forming a conductive sheet, comprising:   Step 1 of forming a pattern layer from a drawing composition containing as a main component an active energy ray curable composition other than a photocationically polymerizable compound on the surface of a conductive thin film layer of a transfer film having a conductive thin film layer on a substrate film Step 2 for pressure-bonding the pattern layer to an insulating substrate, Step 3 for irradiating the pattern layer with active energy rays to completely cure the drawing composition, and transferring the pattern layer and the conductive thin film layer, and And a step 4 of peeling the substrate film.   The method for forming a conductive sheet according to any one of claims 13 to 16, wherein the pattern layer is formed by inline flexographic printing.

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