JP2011096225A - Electrode film for touch panel and touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode film for a touch panel and a touch panel (i) which has a resistance value of 5 to 5,000 Ω/sq., (ii) has sufficient flexibility, (iii) is high in adhesion between a conductive unit and a transparent base material, (iv) has a light transmittance of at least 70% in a visible light range, and reduces manufacturing cost. <P>SOLUTION: A thickness of a portion in which a conductive pattern layer 3 of a primer layer 2 is formed is thicker than that of a portion in which any conductive pattern layer is not formed and a conductive composition includes conductor particles and binder resins. The distribution of the conductor particles in the pattern layer provides the touch panel electrode film and the touch panel using the film (i) which is relatively thin in the vicinity of the primer layer, and thick in the vicinity of a top of the conductive pattern layer, or (ii) is relatively large in the intervals of the conductor particles on the vicinity of the primer layer and small in the vicinity of the top of a convexity pattern layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrode film for a touch panel and a touch panel.

  The touch panel is used as an input device mounted on a screen of a display device such as a liquid crystal display or a plasma display. Capacitance method, optical method, ultrasonic method, resistance film (thin film resistance) method, etc. have been proposed as touch panel formats depending on the input position detection method. It is widespread because of its simplicity. A general thin film resistance type touch panel uses two electrode films having a transparent conductive film made of ITO (tin-added indium oxide) or the like on the surface, with the electrode films facing each other so that the transparent electrode film faces each other, and spacers Etc. so as to be spaced apart at regular intervals.

  Such a conventional thin film resistance type touch panel has a problem of improving light transmittance while maintaining appropriate electrical conductivity (appropriate electrical resistance value) required for touch panel applications. In response to this problem, Patent Document 1 below proposes an electrode film in which a transparent film formed on an electrode film made of an ITO thin film is provided with a missing portion, and the light transmittance is improved by the presence of the missing portion. Yes.

  However, in the conventional thin film resistance type touch panel, including the case of Patent Document 1, a transparent conductive film such as ITO is formed, but this transparent conductive film is brittle and cracked due to bending, The problem of peeling off remained. In order to solve this problem, Patent Document 2 below proposes an electrode film that does not use an ITO thin film transparent conductive film. Specifically, there has been proposed an electrode film in which a lattice network-like opening pattern is formed with a resist film, and a lattice network-like metal film is formed on the open pattern by electroless plating.

Japanese Patent Laid-Open No. 10-326152 JP 2004-192093 A WO2008-149969 pamphlet

  However, the electrode films described in Patent Document 1 and Patent Document 2 are both obtained by a method in which an ITO film is formed by vacuum deposition or sputtering having a slow film formation rate, or a conductive metal film is formed by an electroless plating method. Therefore, the productivity is inferior, and the manufacturing cost cannot be reduced.

On the other hand, as a technique requiring a transparent conductive film, there is an electromagnetic wave shielding material for shielding electromagnetic waves leaking on the front side (observer side) of the plasma display panel.
The present applicant relates to the technology of a conductive film that can be applied to a touch panel, and an electromagnetic wave shield formed by transferring a conductive material composition onto a transparent substrate by specific intaglio printing to form a conductive pattern. In the material, an electromagnetic wave shielding material that does not cause defects such as pattern disconnection, shape defect, insufficient transfer rate, and low adhesion due to poor transfer of the conductive material composition has been proposed (see Patent Document 3).
The conductive film obtained by this method is capable of high-speed production compared to vacuum deposition and sputtering, and is more flexible than ITO thin film and hardly cracks when bent, and is required for touch panel applications. It is possible to achieve a balance with appropriate electrical conductivity.
However, it has been found that the following problem to be solved still remains in this method.

[Problem 1]
As a recent trend, in the case of touch panel electrodes, compatibility between moderate conductivity and high transparency is required. In particular, in the case of a fine line pattern made of a conductive composition like the conductive film described in Patent Document 1, in order to obtain a more highly transparent pattern, the line width of the pattern should be further refined. Is required. Specifically, a thin line having a line width of 30 μm or less, more preferably 15 to 20 μm or less has been demanded.
On the other hand, when the line width of the conductive pattern layer made of the conductive composition containing the conductive particles and the binder resin becomes thin like this;
(1) Generally, the electrical resistance R of an object is proportional to its length L and volume resistivity ρ, and inversely proportional to its cross-sectional area S. That is, R = ρL / S. Therefore, when the same conductive pattern (constant ρ) and the same pattern in plan view (constant L) and the same thickness pattern are printed, the cross-sectional area S decreases in proportion to the decrease in line width. In addition, the electrical resistance R of the conductive pattern portion is increased. Along with this, the surface resistivity as an electrode film for a touch panel increases and deviates from the appropriate range.
(2) When the print thickness is constant, the pattern line width becomes narrower, and when the line width and the conductor particle diameter approach each other, even if the conductor particle has the same particle diameter and particle shape, the unit of the fine line pattern In the cross-sectional area, the ratio of the total area of the portion where the conductor particles are in contact with each other decreases. As a result, compared to the geometrical cross-sectional area S _GEO, the effective total cross-sectional area S _AV conductor particles that can be a real current path (s) is reduced (S _AV <S _GEO), an electrical conductive pattern portion Since the resistance R becomes higher than the influence of the geometric factor (cross-sectional area S) due to the reduction in the line width, the surface resistivity of the electrode film for touch panel also rises to a value simply calculated from the line width. As a result, the electrode film characteristics for touch panels are degraded. This situation occurs in the same way even when the thickness is reduced without changing the line width. Therefore, even when the printing thickness is reduced and approaches the conductor particle diameter, the surface resistivity is rapidly increased.
Of course, if a low volume resistivity metal layer is formed on the conductive pattern layer by electrolytic plating or the like, this increase in electrical resistance can be offset. However, in this case, the number of processes and material costs increase and the yield decreases.

[Problem 2]
In addition, since the conductive particles generally have a high visible light reflectance, the conductive composition has a high visible light reflectance. In particular, metal particles tend to have this tendency. Especially, in the case of scaly conductor particles that are usually employed to reduce resistance, the surface of the conductive pattern has a mirror-like surface when viewed globally. Such reflection becomes close to specular reflection. In the case of high visible light reflectivity, especially when there are many specular reflection components, the surface of the conductive pattern (both on the transparent substrate side surface and the opposite side surface to the transparent substrate) is external light such as electric light, sunlight, or from the display device. There arise problems that the image light is reflected and the screen is whitened or the image contrast is lowered.
Of course, if conductive particles having a low visible light reflectance such as graphite are used, such whitening of the screen and reduction of contrast due to the conductive pattern can be prevented. However, in that case, since the volume resistivity of graphite is higher than that of metal such as silver, the conductivity is inferior when the same conductive pattern is designed. This is relatively unlikely to be a problem when the line width is wide, but when the conductive pattern is thinned, the electrode film performance for touch panels is combined with the increase in electrical resistance due to geometric factors as described above. There arises a problem that it leads to shortage. In addition, carbon particles such as graphite often increase the structural viscosity of the conductive composition and lower the fluidity, and this may cause poor reproducibility of fine line patterns and a tendency to lower the transition rate. It becomes a problem.

[Problem 3]
Furthermore, as a problem, in the transfer step, the release of the primer layer and the printing plate (hereinafter referred to as “release”) that occupies a wide contact area with the printing plate is not smooth (heavy), and FIG. As shown in the figure, if it is normal, the sheet peeling start point (normal point) P, which is a tangential position between the intaglio roll 62 and the nip roll 67, is dragged by the movement of the intaglio roll 62, for example, the limit point P shown in FIG. The operation of reaching 'and returning to the normal point P may be repeated periodically to exhibit a vibrational release state. In such a vibrational release state, the conductive pattern surface is subjected to vibrational modulation such as an increase or decrease in thickness, resulting in the appearance of striped unevenness S as shown in FIG. In addition, there was a problem that a part of the uncured conductive ink composition of the pattern-like line portion was scattered in the form of dots in the opening due to vibration during release. As shown in FIG. 10B, when the scattered matter G is present in the opening, it may cause poor appearance and a decrease in light transmittance, and may not be usable as an electrode film for a touch panel.
Thus, it has been found that the reproducibility varies, the yield of good products is not always satisfactory, and the resistance value needs to be further adjusted for use as an electrode film for a touch panel.

  The present invention has been made in view of the above problems, and the line width of the pattern is further miniaturized, specifically, a line width of 30 μm or less, more preferably 15 to 20 μm or less is required. In the electrode film for touch panel, (i) the dispersed state of the conductive particles or the electrical contact between the conductive particles is improved, the resistance value is 5 to 5000Ω / □, and (ii) the flexibility (flexi (Iii) Highly adhesive between the conductive part and the transparent base material, (iv) Light transmittance of 70% or more in the visible light region, and can reduce the manufacturing cost An object is to provide an electrode film and a touch panel.

  As a result of intensive studies to solve the above problems, a conductive pattern layer comprising a transparent substrate, a primer layer formed on the transparent substrate, and a conductive composition formed in a predetermined pattern on the primer layer An electrode film for a touch panel having a thickness of a portion of the primer layer where the conductive pattern layer is formed is larger than a thickness of a portion where the conductive pattern layer is not formed, and the conductive layer The composition comprises conductive particles and a binder resin, and the distribution of the conductive particles is relatively sparse in the vicinity of the primer layer and dense in the vicinity of the top of the conductive pattern layer. Or the gap between the conductive particles is large in the vicinity of the primer layer and small in the vicinity of the top of the conductive pattern layer. In order to prevent the occurrence of dot-like scattered matter G in the opening and striped unevenness S in the conductive pattern layer due to vibrational release, a release agent is added to the primer layer, and the surface resistivity is further increased as necessary. It has been found that the reduction can be achieved by performing a treatment for bringing the conductive layer into contact with water or an acid at the same time as or after the curing step for forming the conductive layer. The present invention has been completed based on such findings.

That is, the present invention
(1) An electrode film for a touch panel having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer. And
Of the primer layer, the portion where the conductive pattern layer is formed is thicker than the portion where the conductive pattern layer is not formed, and the conductive composition contains conductor particles and binder resin. The distribution of the conductive particles in the conductive pattern layer is relatively sparse in the vicinity of the primer layer and dense in the vicinity of the top of the conductive pattern layer. Electrode film for touch panel,
(2) An electrode film for a touch panel having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer. And
Of the primer layer, the portion where the conductive pattern layer is formed is thicker than the portion where the conductive pattern layer is not formed, and the conductive composition contains conductor particles and binder resin. The touch panel is characterized in that the distance between the conductive particles in the conductive pattern layer is relatively large in the vicinity of the primer layer and small in the vicinity of the top of the convex pattern layer. And (3) a touch panel in which the electrode surfaces of the two electrode films are opposed to each other at a constant interval, and the electrode film for at least one of the touch panels according to (1) or (2) A touch panel using an electrode film,
Is to provide.

The electrode film for a touch panel obtained by the present invention has (i) high adhesion between the conductive pattern layer (conductive portion) and the transparent substrate, (ii) the surface electrical resistance is adjusted to 5 to 5000 Ω / □, iii) It is rich in flexibility, and (iv) has a light transmittance of 70% or more in the visible light region, and can be reduced in cost.
When used as a transparent electrode for a touch panel, the one arranged on the operator side sees the conductive pattern layer from the transparent substrate side. In that case, the conductive particles near the primer layer in the conductive pattern layer forming part Since the distribution is sparse, reflection by the conductive particles is suppressed, the contrast of the display device of the display such as a liquid crystal display device is not disturbed, and the distribution of the conductive particles is close to the top of the conductive pattern layer, Conductivity is good at the time of contact with the other electrode of the touch panel, and the function can be expressed with a light touch.
Moreover, if an electrical resistance reduction process is performed as needed, the addition amount of a conductor particle can be reduced and cost reduction can be achieved.

It is a schematic cross section which shows three examples of the electrode film for touchscreens which concerns on this invention. It is a typical schematic top view of the electrode film for touchscreens which concerns on this invention. It is the model perspective view which expanded the conductive pattern (conductive mesh). It is a schematic cross section which shows the touch panel which has arrange | positioned the electrode film for touchscreens shown in FIG. 1 as an electrode film of both the input side and a display apparatus side. It is a schematic cross section which shows the touchscreen which has arrange | positioned the electrode film for touchscreens shown in FIG. 1 as an electrode film of an input side. It is process drawing which shows an example of the manufacturing method of the electrode film for touchscreens which concerns on this invention. It is explanatory drawing of (A) normal release state and (B) abnormal release state in the process of transferring a conductive material composition on a primer layer. It is a cross-sectional SEM photograph of the conductive pattern in the electrode film for touchscreens of this invention. It is a cross-sectional SEM photograph of the conductive pattern in which the conductor particles are partially fused. (A) It is explanatory drawing of the striped nonuniformity of a conductive pattern layer, (B) It is explanatory drawing of the scattered matter in the opening part of a conductive pattern. It is a schematic plan view which shows an example of the electrode film used for a multi-touch type touch panel. It is a conceptual diagram of the conductor particle density distribution in a conductive pattern layer.

  Next, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

  An electrode film 10 for a touch panel according to the present invention (hereinafter simply referred to as “electrode film 10”) is a primer provided on a transparent substrate 1 and one surface S1 of the transparent substrate 1, as shown in FIG. Layer 2, conductive pattern layer (conductive mesh) 3 made of a conductive composition provided in a predetermined pattern on primer layer 2, and hard coat provided on the other surface S <b> 2 of transparent substrate 1 as necessary. Layer 4.

  1A to 1C, an electrode film 10A shown in FIG. 1A is provided with a primer layer 2 and a conductive pattern layer 3 in this order on one surface S1 of the transparent substrate 1. In this embodiment, the hard coat layer 4 is provided on the other surface S2 of the transparent substrate 1. In the electrode film 10 </ b> B shown in FIG. 1B, the primer layer 2 and the conductive pattern layer 3 are provided in this order on one surface S <b> 1 of the transparent substrate 1, and the other surface S <b> 2 of the transparent substrate 1. In this embodiment, the easy adhesion layer 5, the hard coat layer 4, and the AR layer (antireflection layer) 6 are provided in that order. In the electrode film 10C shown in FIG. 1C, the primer layer 2 and the conductive pattern layer 3 are provided in this order on the other surface S1 of the transparent substrate 1, and the filling layer 9 is provided in the opening 19 between the conductive meshes. This is an embodiment in which the easy adhesion layer 5, the hard coat layer 4, and the AR layer (antireflection layer) 6 are provided in this order on the other surface S <b> 2 of the transparent substrate 1.

  Further, as shown in FIG. 2, the planar form of the electrode film 10 includes a conductive mesh pattern portion 7 formed of a conductive pattern layer located at the center and facing the display surface of the display device, and the conductive mesh pattern portion 7. Although it has a peripheral portion 8 (wiring is omitted) around which a conductive mesh pattern is not formed, it is not necessarily limited to the illustrated form. FIG. 3 is a perspective view schematically showing an enlarged state of the conductive pattern layer 3 formed with the line width W and the line pitch P. FIG.

As shown in FIGS. 4 and 5, touch panels 50 </ b> A and 50 </ b> B according to the present invention are touch panels in which electrode surfaces of two electrode films (10 and 20 or 10 and 30) are opposed to each other at a constant interval G. And the electrode film 10 of the input side which the input pen 40 etc. contacts at least has the conductive pattern layer (conductive mesh) 3 as an electrode.
The electrode film on the display (fixed) side may be the electrode film 20 according to the present invention, or a conventional electrode film, as shown in FIG. The electrode film 30 formed on 21 may be used.

In addition, FIG. 11 is the electrode film 70 which comprises the touchscreen for multitouch.
As shown in FIG. 11, the multi-touch electrode film 70 is provided on a transparent substrate as a conductive mesh 71 divided into a plurality of regions. Reference numeral 72 denotes a wiring from each conductive mesh 71. Although not shown, the wiring also protrudes from the right side of the conductive mesh 71.
When a touch panel is configured with such multi-touch electrode films 70, two electrode films 70 in FIG. 11 are used, and one electrode film 70 has a conductive mesh 71 whose longitudinal direction is in the horizontal direction as shown in FIG. The other electrode film 70 is preferably disposed so that the longitudinal direction of the conductive mesh 71 is up and down, and the longitudinal directions of the conductive mesh 71 of the two electrode films 70 are orthogonal to each other. The electrode film 70 of the present invention has an advantage that the conductive mesh 71 can be formed by printing means, and can easily cope with such a conductive mesh pattern.

  Hereinafter, each configuration will be described in detail.

(Transparent substrate)
The transparent substrate 1 is a substrate of the electrode film 10 and has various thicknesses of various materials preferable for a touch panel in consideration of required transparency such as desired transparency, mechanical strength, and adhesion with the primer layer 2. You can select one. The material of the transparent substrate 1 may be a resin substrate or an inorganic substrate such as a glass substrate, but when used as the electrode film 10 on the input side, the opposing electrode film (Refer to reference numerals 20 and 30 in FIGS. 4 and 5) is required to be flexible enough to be in contact with the conductor. On the other hand, when used as the electrode films 20 and 30 (see FIGS. 4 and 5) on the display device side, such flexibility may or may not be provided. In addition, the thickness form may be a film shape, a sheet shape, or a plate shape, but it is necessary to have a thickness that can be used as an electrode for a touch panel. In the case of the electrode film 10 on the input side, Usually, a film or sheet-like resin substrate is preferably used. On the other hand, the electrode films 20 and 30 on the display device side are not particularly limited, and may be a resin base material or an inorganic base material, and may be any of a film shape, a sheet shape, and a plate shape.

  The transparent substrate 1 is preferably a film based on an acrylic resin (used here as a concept including a so-called methacrylic resin) or a polyester resin, but is not limited thereto. Specific examples of the resin material include cellulose resins such as triacetyl cellulose, diacetyl cellulose, and acetate butyrate cellulose, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene glycol-terephthalic acid-isophthalic acid copolymer Polymers, polyester resins such as terephthalic acid-ethylene glycol-1,4 cyclohexanedimethanol copolymer, polyester thermoplastic elastomer, polyolefin resins such as polyethylene, polypropylene, polymethylpentene, cyclic polyolefin, polyvinyl chloride, polyvinylidene chloride Halogen-containing resins such as polyether sulfone resins, acrylic resins, polyurethane resins, polycarbonate resins, styrene resins such as polystyrene, polyamide resins Polyimide resins, polysulfone resins, polyether resins, polyether ketone, (meth) acrylonitrile and the like can be used. Among them, the biaxially stretched PET film is preferable in that it has excellent transparency and durability, and has heat resistance that does not cause thermal deformation even when subjected to ultraviolet irradiation treatment or heat treatment in the subsequent steps.

  On the other hand, inorganic materials constituting the inorganic base material include soda glass, potash glass, lead glass, borosilicate glass, quartz glass, phosphate glass, etc., crystalline quartz (quartz), calcite (calcium carbonate), diamond ( Examples thereof include transparent inorganic crystals such as gold goethite and transparent ceramics such as PLZT (lead lanthanum zirconate titanate).

  The transparent substrate 1 may be a continuous long belt-like film that can be processed by rolls, tows, or rolls, or may be a sheet film having a predetermined size. Here, the term “roll toe roll” means that a long belt-like base material is supplied in the form of a roll (roll), and the belt-like sheet is unwound from the roll to perform a predetermined process, and thereafter It means a form of use of the film that is wound up, stored and transported again in the form of winding.

  Although the thickness of the transparent base material 1 varies depending on the material, in the case of, for example, a PET base material that is preferably used as the electrode film 10 on the input side, it is usually preferably about 100 μm to 188 μm. On the other hand, in the case of a resin base material or an inorganic base material (glass base material) used as the electrode films 20 and 30 on the display device side, it is not particularly limited, but is usually about 50 to 5000 μm.

  As the light transmittance of the transparent substrate 1, since the touch panels 50A and 50B are installed on the front surface of the display device, 100% is ideal, but preferably the transmittance is 70% or more, more preferably. Select 80% or more. If necessary, an easy-adhesion layer (not shown) is provided on the surface of the transparent substrate 1 in order to improve the adhesion between the primer layer 2 and the transparent substrate 1 described later, or corona discharge treatment or plasma treatment. Further, surface treatment such as flame treatment may be performed. As an easily bonding layer, it comprises from resin which has adhesiveness in both the transparent base material 1 and the primer layer 2. FIG. The resin for the easy adhesion layer is appropriately selected from resins such as urethane resin, epoxy resin, polyester resin, acrylic resin, and chlorinated polypropylene.

(Primer layer)
The primer layer 2 is provided on the transparent substrate 1 with good adhesion. A conductive pattern layer 3 is provided on the primer layer 2 with good adhesion. Therefore, the primer layer 2 is preferably a material having good adhesion to both the transparent substrate 1 and the conductive pattern layer 3, and is a constituent layer of the touch panels 50A and 50B provided on the front surface of the display device. Therefore, it is naturally preferable to be transparent. For example, a layer formed by applying an ionizing radiation curable resin or a thermoplastic resin is preferable. Various additives and modified resins may be used to improve adhesion, durability, and impart various physical properties.

  Examples of the thermoplastic resin include acrylic resins such as polymethyl methacrylate (PMMA), vinyl chloride-vinyl acetate copolymers, polyester resins, and polyolefin resins.

As the ionizing radiation curable resin, a monomer (monomer) that is polymerized and cured by a reaction such as crosslinking with ionizing radiation, or a prepolymer or an oligomer is used.
Examples of the monomer include radical polymerizable monomers, specifically 2-ethylhexyl (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri ( Examples thereof include various (meth) acrylate monomers such as (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. In addition, cationically polymerizable monomers, specifically, alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, 4 -Vinyl ethers such as hydroxybutyl vinyl ether, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane.
The prepolymer (or oligomer) is, for example, a radical polymerizable prepolymer, specifically, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate. And (meth) acrylate prepolymers, trimethylolpropane trithioglycolate, polythiol-based prepolymers such as pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. In addition, cationically polymerizable prepolymers such as novolac epoxy resin prepolymers, aromatic vinyl ester resin prepolymers, and the like can be given. Here, the notation of (meth) arylate means an acrylate or methacrylate.

  These monomers or prepolymers may be used alone or in combination of two or more types of monomers, two or more types of prepolymers, or one or more types of monomers, depending on the required performance, applicability, etc. And one or more prepolymers can be mixed and used.

  As the photopolymerization initiator, in the case of a radically polymerizable monomer or prepolymer, a compound such as benzophenone, acetophenone, thioxanthone, or benzoin is used, and in the case of a cationic polymerization monomer or prepolymer, Metallocene, aromatic sulfonium and aromatic iodonium compounds are used. These photopolymerization initiators are added in an amount of about 0.1 to 5 parts by mass with respect to 100 parts by mass of the composition comprising the monomer and / or prepolymer.

  The ionizing radiation is typically ultraviolet rays or electron beams, but other than these, electromagnetic waves such as visible rays, X-rays and γ rays, or charged particle beams such as α rays can also be used.

  Additives are added as necessary. Examples of the additive include a heat stabilizer, a radical scavenger, a plasticizer, a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, an infrared absorber, a dye (colored dye, colored pigment), and an extender pigment. And a light diffusing agent.

  When using a material system that peels heavily after curing the primer layer on the plate surface (if it has a good adhesion to the plate), release the plate surface or apply a release material However, considering the processing cost and the life of mold release capability, a mold release agent is added to the primer layer as necessary. The mold release agent used in the present invention means that the primer layer on the transparent substrate that has undergone the primer curing step reduces the force (peeling force) required for peeling from the plate surface in the production of an electrode film for a touch panel, and smoothly An additive for improving peelability so as to peel off. Examples of such release agents include higher fatty acid esters, phosphate esters, silicone resin release agents, fluororesin release agents, and the like of mono- or polyhydric alcohols.

The higher fatty acid ester is preferably a partial ester or complete ester of a monovalent or polyhydric alcohol having 1 to 20 carbon atoms and a saturated fatty acid having 10 to 30 carbon atoms. Examples of partial esters or complete esters of mono- or polyhydric alcohols and saturated fatty acids include stearic acid monoglyceride, stearic acid monosorbate, behenic acid monoglyceride, pentaerythritol monostearate, pentaerythritol tetrastearate, propylene glycol monostearate , Stearyl stearate, palmityl palmitate, butyl stearate, methyl laurate, isopropyl palmitate, 2-ethylhexyl stearate and the like.
Among these, stearic acid esters such as stearic acid monoglyceride and pentaerythritol tetrastearate are particularly preferable from the viewpoints of transparency and releasability.
These release agents can be used alone or in combination of two or more.
The release agent is preferably added in an amount of 0.1 to 5 mass%, particularly preferably 0.5 to 3 mass%, based on the total amount of the ionizing radiation curable resin composition forming the primer layer. If it is less than 0.1% by mass, the releasability from the plate surface of the primer layer is not improved, and even if it is added in excess of 5% by mass, the release performance is saturated and it is not economical.

  The ionizing radiation curable resin composition may contain a solvent, but in that case, since a drying step is required after coating, it is a type that does not contain a solvent (non-solvent type or non-solvent type) in view of processing costs. It is preferable. When a solvent is added for the purpose of improving the appearance or coating applicability, drying is necessary. However, if the amount of the solvent is about several percent, it may be dried after curing. The amount of residual solvent is preferably as small as possible, but may not be completely zero as long as there is no influence on physical properties and durability.

  Although the thickness of the primer layer 2 is not particularly limited, it is usually formed to have a thickness after curing of about 1 μm to 100 μm. Further, the thickness of the primer layer 2 is usually about 1 to 50% of the total value of the thickness of the conductive pattern layer 3 and the thickness of the primer layer 2. As will be described later in the explanation of the production method, the primer after the conductive composition 3 ′ is transferred onto the primer layer 2 and the conductive composition 3 ′ is further cured to produce the electrode film 10. As shown in FIG. 6D, the layer 2 has a thickness TA where the conductive pattern layer 3 is formed thicker than a thickness TB where the conductive pattern layer 3 is not formed. ing.

(Conductive pattern layer)
The conductive pattern layer 3 is provided in a predetermined pattern on the primer layer 2. As the pattern, a mesh (mesh pattern or lattice pattern) pattern is representative, but a stripe (striped pattern or parallel line group) pattern, a spiral (spiral or spiral) pattern, or the like is also used. The conductive composition for forming the conductive pattern layer 3 is not particularly limited as long as it finally becomes a conductive layer after various processes. In the case of a typical conductive mesh pattern, as shown in FIG. 3, for example, the line width W can be 5 to 200 μm, and the line pitch P can be 100 to 1000 μm. The aperture ratio (ratio of the total area of the openings 19 in the total area of the conductive mesh pattern) is usually about 50 to 95%.

  In addition, the thickness Tc (see FIG. 6D) of the conductive pattern layer 3 varies depending on the resistance value of the conductive pattern layer 3, but is usually 2 μm in the measurement at the central portion (the top portion of the projection pattern). It is not less than 50 μm and preferably not less than 5 μm and not more than 20 μm.

As shown in FIG. 6, the conductive pattern layer 3 is formed by filling the concave portion 64 provided on the plate surface 63 of the printing plate 62 with the conductive composition 3 ′ and transferring it onto the primer layer 2. Such a conductive composition 3 ′ has fluidity when it is filled in the concave portion 64 of the plate 62, and exhibits desired conductivity after being formed into a desired pattern and cured. There is no particular limitation, and various materials and forms can be used. A typical example includes a fluid ink or paste-like material containing conductive particles and a binder resin, and further containing a solvent or a dispersant for dissolving or dispersing the resin as necessary. . The conductive pattern layer 3 made of the conductive composition 3 ′ is a coating film made of a solid after the conductive composition 3 ′ is dried or cured. The reason why the composition is dissolved or dispersed is that the conductive composition 3 ′ includes a colloidal form as well as a solution form.
As shown in the conceptual diagram of FIG. 12, the conductive pattern layer 3 made of a conductive composition containing such conductive particles and a binder resin has conductive particles Cp as described later, and FIGS. 8 is distributed in a specific distribution state as shown in FIG. 8, and as shown in FIG. 8, at least a part of the conductor particles Cp is formed by contact or fusion of adjacent conductor particles Cp. It is characterized in that a path serving as a current path composed of the series is formed. Between these conductor particles Cp, a binder resin R is interposed in a gap except for a contact or fusion between adjacent conductor particles, and the conductor particles Cp in the conductive pattern layer 3 are bound to each other. Become.

  For example, as described later, the viscosity of the conductive composition 3 ′ is such that the primer component in the primer layer 2 penetrates into the conductive composition 3 ′ to increase the viscosity, or the primer layer 2 and the conductive composition 3 ′. However, the range of usable viscosity is usually within the range of 100 mPa · s to 1000000 mPa · s. Yes, preferably in the range of several thousand mPa · s to tens of thousands mPa · s.

As the binder resin constituting the conductive composition 3 ′, any of thermosetting resins, ionizing radiation curable resins, and thermoplastic resins can be used. In addition, when performing the below-mentioned electrical resistance reduction process, the water-insoluble resin which does not melt | dissolve with an acid or warm water is used. Examples of such binder resins include, for example, melamine resins, polyester-melamine resins, epoxy-melamine resins, polyimide resins, thermosetting acrylic resins, thermosetting polyurethane resins, phenol resins, thermosetting resins. Resin such as polyester resin can be mentioned, as ionizing radiation curable resin, those mentioned above as the material for the primer layer can be mentioned, and as thermoplastic resin, polyester resin, polyvinyl butyral resin, acrylic resin, A resin such as a thermoplastic polyurethane resin can be used. These resins may be used alone, or a plurality of resins may be mixed and used.
In addition, when using a thermosetting resin, you may add a curing catalyst as needed. When using an ionizing radiation curable resin such as an ultraviolet curable resin, a polymerization initiator may be added as necessary.

Further, in order to obtain fluidity suitable for filling the concave portion 64 of the plate 62, these resins are usually used as a varnish dissolved in a solvent. There is no restriction | limiting in particular in the kind of solvent, The solvent generally used for printing ink can be used. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone and cyclopentanone, ethers such as methyl ether and ethyl ether, ethyl acetate, butyl acetate, methyl butyrate, diethylene glycol-n-butyl ether, ethylene glycol monobutyl ether Ester cheeks such as acetate, aliphatic hydrocarbons such as pentane, hexane, and octane, aromatic hydrocarbons such as benzene, toluene, xylene, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, terpineol, etc. One to two or more kinds appropriately selected from alcohols, water and the like are used. The content of the solvent is usually about 10% by mass to 70% by mass, but is preferably as small as possible within a range where necessary fluidity can be obtained.
In addition, when an ionizing radiation curable plastic resin such as an ultraviolet curable resin is used, a solvent is not necessarily required because it is inherently fluid.

Further, the conductive particles constituting the conductive composition 3 ′ are made of low resistivity metal particles such as gold, silver, platinum, copper, tin, palladium, nickel, aluminum, or materials other than the low resistivity metal. The surface of the particles (metal particles other than the above low resistivity metals, resin particles such as acrylic resin and melamine resin, inorganic particles such as silica, alumina, barium sulfate, and zeolite) is plated with a low resistivity metal such as gold or silver. And particles of conductive carbon such as graphite and carbon black. In addition, particles of conductive ceramics or conductive organic polymer compounds can also be used. The shape can also be selected from a spherical shape, a spheroid shape, a polyhedron shape, a scale shape, a disk shape, a fiber shape (or needle shape), and the like. These materials and shapes may be appropriately mixed and used.
Since the size of the conductor particles is arbitrarily selected according to the type, it cannot be specified unconditionally. For example, in the case of flaky silver particles, those having an average particle diameter of about 0.1 to 10 μm are used. In the case of carbon black particles, those having an average particle diameter of about 0.01 to 1 μm can be used.

  The content of the conductive particles in the conductive composition 3 ′ is arbitrarily selected according to the conductivity of the conductive particles and the form of the particles, but the expression of electrical resistance suitable for the electrode film for the touch panel, the conductive pattern In order to combine the maintenance of the mechanical strength and the printing suitability, for example, among 100 parts by mass of the solid content of the conductive composition 3 ′, 40 to 99 parts by mass, preferably 90 to 97 parts by mass of the conductive particles are used. It can be contained in a range. In the present application, the average particle diameter refers to a value measured by a particle size distribution meter or TEM observation. In the case of an aspherical shape such as a polyhedral shape or a fibrous shape, the particle diameter is usually defined by the diameter of the circumscribed sphere, the diagonal length, or the side length of the longest side.

  In the present invention, since the conductive pattern layer 3 is formed by printing (transferring from an intaglio to a transparent substrate) a conductive composition 3 ′ having a binder resin component and a conductive component, If the composition is adjusted, the resistance value of the conductive pattern layer 3 can be easily controlled. On the other hand, there are hard and soft binder resin components, and there is also a difference in light resistance. Therefore, if the type and blending amount are adjusted, the durability of the conductive pattern layer 3 can be controlled. it can. As a result, the conductive pattern layer 3 is not destroyed and the conductive pattern layer 3 having a desired resistance value can be provided.

Moreover, you may add an appropriate additive for the purpose of quality improvement etc. to electrically conductive composition 3 'as needed. For example, carbon black is not necessary because it is black in itself, but by adding a predetermined amount of black pigment or black dye as necessary, the contrast when the touch panels 50A and 50B are configured is improved and visibility is improved. Can be improved. In addition, it is desirable to contain such a black pigment or black dye in order to prevent reflection due to metallic luster when the metal layer is provided, to suppress color unevenness, metal color, and the like. Examples of black pigments include 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 , which also function as conductive particles. The type and shape are not particularly limited, and a black pigment or black dye having a large coloring power with an average particle diameter of 0.1 μm or less that can be easily dispersed in the binder resin is preferable. In addition, when using carbon black, carbon black for coloring materials such as channel black, furnace black or lamp black, conductive carbon black, acetylene black and the like can be mentioned, and among them, the average particle diameter is 20 nm or less. Is preferably used. As the black dye, a dye such as aniline black can be used. Moreover, in order to improve the fluidity and stability of the conductive composition 3 ′, as long as the conductivity and adhesion to the primer layer 2 are not adversely affected, a filler, a thickener, a surfactant, An antioxidant or the like may be added.
In general, particles having an average particle size as small as several tens of nanometers called “nanoparticles” lead to high costs, and when a binder resin is added, the performance is lowered and the stability as an ink is also lowered. As for the particle size distribution, in order to reduce the electric resistance of the obtained conductive pattern, rather than a narrow distribution width and close to a single particle size, as shown in FIG. It is better to consist of a mixed system with particles of relatively small particle size. For example, a mixed system of small particle diameter particles having a particle diameter of 0.01 μm to 1 μm and large particle diameter particles having a particle diameter of 5 to 10 μm is preferable. The mixing ratio of both particles in such a mixed system is such that the number of small particles: the number of large particles: 1: 9 to 9: 1, in particular, the number of small particles: the number of large particles: 5: 5. A range of ˜9: 1 is preferred. Naturally, if particles larger than the line width and thickness of the pattern are mixed, defects such as omissions and streaks occur frequently during printing, so the average size or the maximum particle size of the large particle size varies depending on the pattern design. come.
In addition to mixing a plurality of types of particles having different average particle sizes, particles having a certain particle size distribution may be used from the beginning.

The reason why the surface resistivity of the conductive composition (the conductive pattern layer made of the conductive composition layer) decreases when the particle diameter of the conductive particles is a mixed system of small particle diameter particles and large particle diameter particles is that When the cross-section of the conductive pattern layer made of is observed with a microscope, there is no contact between the large particle size particles, presuming that a distribution in which the small particle size particles are filled in the gaps in which the large particle size particles are distributed is observed. The gap between the portions is reinforced by the contact of the small particle diameter particles interposed therein, and the sum of the electrical contact areas between the large and small particles dispersed in the conductive composition is increased (the above formula R = ρL / S It is considered that the cross-sectional area S increased in FIG.
The distribution of the conductive particles in the conductive pattern layer can be selected from various forms according to desired characteristics and manufacturing suitability, and it extends from one end to the other end in the conductive pattern layer. It is necessary to secure one or more paths through which current can flow. For that purpose, as shown in FIG. 8, it is necessary that at least one path formed by connecting the adjacent conductor particles with a structure in which the distance between the particles is 0 or in contact or fusion is present. As a particularly preferable form for forming such a path, as shown in the electron micrograph of FIG. 8, the interval between the particles is relatively small in the vicinity of the top of the conductive pattern layer (direction away from the primer layer). On the other hand, in the vicinity of the bottom of the conductive pattern layer (in the direction approaching the primer layer), there is a distribution in which the interval between the particles is relatively large.
For that,
(I) As conceptually shown in FIG. 12, the number density of particles in the conductive pattern layer, that is, the number of particles per unit volume is relatively high near the top (densely), and the primer The particles are distributed so that the particle number density is low (sparse or coarse) in the vicinity of the layer.
(Ii) The particle number density in the conductive pattern layer is constant, and the particle size is distributed so as to be relatively large near the top and small near the primer layer.
(Iii) Relatively, the particle number density is increased and the particle diameter is increased in the vicinity of the top, and the particle number density is decreased and the particle diameter is decreased in the vicinity of the primer layer.
Any one of the distribution forms is adopted. 8 and 9 correspond to the form (iii).

The distribution of the number density of the conductive particles in the convex pattern layer will be described in detail. In the present invention, as conceptually shown in FIG. 12, the distribution of the conductive particles Cp in the conductive pattern layer 3 is shown. It is preferable that the distribution is relatively sparse in the vicinity of the primer layer 2 and the distribution is close in the vicinity of the apex P.
That is, inside the conductive pattern layer 3 (convex portion), the conductor particles Cp are not uniformly distributed, but the distribution of the conductor particles Cp is relatively at the top portion P (top portion) of the convex portion. An internal structure having a distribution in which the vicinity is dense and the vicinity of the primer layer 2 far from the top P is sparse is preferable.
The term “dense” refers to the number density (volume density) of the conductor particles Cp in the unit volume as viewed from the number of particles. That is, the distribution is such that the number density of the conductor particles Cp inside the convex portion is larger near the top portion P than near the primer layer 2.

The ratio of the number density of the conductor particles Cp at the top P of the conductive pattern layer 3 when the number density of the conductor particles Cp in the region adjacent to the interface 14 with the primer layer is 1 is large. This is advantageous in achieving the effect of the distribution of the number density of the conductor particles.
On the other hand, as the ratio of the number density is increased, the manufacturing conditions are restricted and the difficulty in realization increases, and the physical limit of density increase due to the particle size of the conductor particles (close-packed structure is reduced). There is also a possibility of higher density than that). Considering these, as described above, when considering the material and average particle size of the conductive particles, the line width of the conductive pattern layer, the manufacturing method, and good electrode film performance for touch panels, the number density ratio, that is, [ “Number density of conductor particles Cp at the top portion P” / “Number density of conductor particles Cp in a region adjacent to the interface with the primer layer”] is preferably in the range of about 1.5 to 10.

It is determined that the distribution state of the conductive particles Cp in the conductive pattern layer 3 is not dependent on the direction in which the conductive pattern layer 3 extends on the transparent substrate 1. That is, the cross-sectional view of the convex portion of the conductive pattern layer 3 shown in FIG. 12 is a cross-sectional view of the main cut surface that is a plane perpendicular to the direction in which the convex portion extends and perpendicular to the sheet surface of the transparent substrate 1. The direction perpendicular to the paper surface is the direction in which the conductive pattern layer extends (extending direction). In the extending direction, the number density of particles in a unit volume is constant if the position in the main cutting plane is the same. Is considered. This is because the conductive pattern layer 3 is continuously manufactured by applying the same conductive resin composition to the intaglio in the manner described later.
Therefore, the number density of the conductor particles Cp in such a unit volume can be evaluated by the number density (area density) of the conductor particles Cp in the unit area on the main cut surface of the arbitrary conductive pattern layer 3. .
That is, as shown in FIG. 12, if the distribution of the surface density of the conductive particles Cp in the main cut surface is larger near the top P than the region adjacent to the interface of the primer layer 2, It may be determined that the volume density of the body particles Cp is also a distribution that is larger in the vicinity of the top portion P than in the vicinity of the primer layer 2.

The density distribution of the conductive particles in the conductive pattern layer is also expressed by measuring the distribution in the thickness direction of the distance between adjacent conductive particles in the conductive pattern layer (hereinafter referred to as “particle interval”). can do. Here, as the layer in the thickness direction, the outermost layer (hereinafter referred to as “the outermost conductive particle interval”) as a top formed by a conceptual line that connects the conductive particles existing along the contour line of the conductive pattern layer. ), And the innermost layer (hereinafter, also referred to as “the innermost conductor particle interval”) formed by a concept line connecting conductor particles existing in the vicinity of the primer layer. It can be a layer. And measure the particle interval of each conductor particle in these layers, that is, the conductor particle interval of the outermost layer and obtain the average, and measure the conductor particle interval of the innermost layer and obtain the average Can be used as an index of the distribution of the conductive particles in the conductive pattern layer. As the number of measurement data of the conductor particle interval in each layer, data of 3 or more, preferably about 10, is taken and averaged. The conductor particle interval is measured by taking a micrograph of the main cut surface and measuring the interval between two adjacent conductor particles.
Further, the distance between the conductor particles in the conductive pattern layer is the distance between the side edge portions in the conductive pattern layer, and the distance between the outermost conductor particles in the central portion corresponding to w / 2 with respect to the apex. Since the conductor particle spacing in the inner layer significantly represents the difference in the distribution of the conductor particles in the conductive pattern layer, these values can be used as the difference in the particle spacing.
The average conductor particle spacing exhibiting high conductivity is preferably in the range of 0 to 0.5 μm for the outermost layer and 0.5 to 3 μm for the innermost layer.

In order to realize such a density of the particle density or a difference in the distance between the conductor particles, that is, to make the conductor particles Cp unevenly distributed on the top P (outermost layer) of the conductive pattern layer, for example, as shown in FIG. The intaglio printing method is employed, and the pressure contact force for pressure-bonding the transparent base material 1 on which the primer fluidized layer 2 has been formed to the plate surface is strengthened, and the conductive composition 3 ′ has a low viscosity and is in the intaglio recess. It is good to solidify after releasing from the plate surface without solidifying.
In addition, the specific gravity difference between the conductive particles Cp and the binder resin, the viscosity of the conductive composition 3 ′ before solidification (the amount of resin material and resin, the amount of solvent, the amount of other additives, the shape of the conductive particles, the particle size distribution, the content Since it depends on solidification (curing) conditions, etc., these may be determined experimentally as appropriate.
The difference in specific gravity between the conductor particles Cp and the binder resin is usually the specific gravity of the conductor particles Cp that are metal particles> the specific gravity of the binder resin. ) In the same direction (downward) as the direction of gravity, the conductive composition layer 3 ′ may be solidified.

The following can be mentioned as effects when there is a difference in density of conductor particles or a difference in conductor particle spacing between the vicinity of the top of the convex pattern layer and the interface of the primer layer as described above.
(I) When the number density is larger or the distance between the conductor particles is smaller, the electrical contact between the conductor particles Cp is more easily performed. Therefore, when there is a sparse distribution or a difference in conductor particle spacing in the number density of the conductor particles Cp in this way, even if the average concentration of the conductor particles Cp in the conductive pattern layer 3 is the same, the same number As compared with the case where the number density of the conductor particles Cp is uniformly distributed or the distance between the conductor particles is evenly distributed, the volume at the portion where the number density is large or the distance between the conductor particles is small. The decrease in resistivity contributes to a decrease in volume resistivity as a whole, and the conductivity performance is improved.
(ii) The adhesiveness between the conductive pattern layer 3 and the primer layer 2 is improved by the small number density of the conductive particles Cp in the vicinity of the boundary with the primer layer 2 or the large interval between the conductive particles.
(iii) For example, when used as an input device mounted on the screen of a display device such as a liquid crystal display or a plasma display, light incident from the transparent substrate 1 side (lower side in FIG. 8) of the electrode film for touch panel Is reflected at the interface between the conductive pattern layer 3 and the primer layer 2, the diffuse reflection component increases and the specular reflection component decreases. Therefore, it is possible to reduce a decrease in image contrast due to multiple reflection of image light incident from the image display device between the interface and the screen.
(iv) Further, in the electrode film for touch panel 10 on the input side in a general use form in which the electrode film for touch panel of the present invention is installed on the front surface of the image display device, that is, the conductive pattern layer 3 side is on the display device side. In the case where the transparent substrate 1 is used with the transparent substrate 1 side facing the viewer side of the image, the conductive particles facing the viewer side have a low density, so that external light (electric light, sunlight, etc.) Is reflected to reduce reflected light, particularly specularly reflected light, that enters the viewer's eyes. As a result, it is possible to prevent whitening of the image and reflection of surrounding scenery in the presence of extraneous light, and to prevent a decrease in image contrast, which is preferable.

In order to exhibit this effect more effectively, it is more preferable to select a polyhedral, spherical, or spheroid shape as the conductive particle shape rather than a scale shape. Since a surface close to a mirror surface is difficult to be formed on the layer side surface, it is preferable. In addition, when adopting a scale-like material as the shape of the conductor particles, the orientation direction of the scale-like conductor particles in the vicinity of the primer layer side in the conductive pattern layer (for example, the widest of the scales) It is preferable to distribute the random distribution (defined as the normal direction of the surface) to reduce the specular reflection. In addition, even when the conductor particle shape is a polyhedral shape, a spherical shape, or a spheroid shape, it is preferable in terms of reducing specular reflection light to make the orientation direction random.
At the same time, the conductive particles in the vicinity of the apex are densely gathered, the electrical contact between the particles is improved, the electric resistance is lowered, and the conductivity with the opposing electrode film as the electrode film is increased. . Of course, the conductive particles distributed at a high density also have a high visible light reflectance, but the conductive particles should be positioned on the surface that is not in contact with the image observer (on the opposite side of the observer). As a result, there is no worry about a decrease in image contrast or the like.
In addition, the structure in which particles are densely present in the vicinity of the top of the conductive pattern layer is advantageous in that if this mesh is used as an electrode film for a touch panel, the resistance value is lowered and a touch panel with high operability can be obtained. have.

As shown in the manufacturing process diagram of FIG. 7A, first, the conductive pattern layer 3 is formed on the plate-like or cylindrical plate surface 63 in which the concave portions 64 are formed with a predetermined mesh pattern. After applying (15), the conductive composition adhering outside the concave portion 64 is scraped off with a doctor blade 65, a wiping roll or the like (not shown) to fill the concave portion 64 with the conductive composition 3 ′. . Next, the transparent base material 1 in which the primer layer 2 retaining fluidity is formed on one surface is prepared, and the primer layer 2 side of the transparent base material 1 and the conductive composition 3 ′ are filled in the recess 64. After the plate surface 63 is pressure-bonded, the conductive composition 3 ′ and the primer layer 2 are brought into close contact with each other without any gap, and the fluidity of the primer layer 2 is lost (cured) in that state or in that state. Then, the conductive composition 3 ′ is transferred onto the primer layer 2 to form the conductive composition 3 ′ having a predetermined mesh pattern.
After the conductive composition 3 ′ is transferred onto the primer layer 2, the conductive composition 3 ′ is subjected to a curing process (for example, a drying process, an ultraviolet / electron beam irradiation process, a heating process, a cooling process, etc.). As a result, the conductive pattern layer 3 is formed.

  In the present invention, as described above, when the excess conductive composition other than the recess 64 is scraped off by a doctor blade, a wiping roll, or the like, as shown in FIG. The primer layer 2 that retains fluidity is filled in the recess 13 formed in the upper part of the conductive composition 3 ′, and the primer layer 2 is half in the state where the conductive composition 3 ′ and the primer layer 2 are closely adhered to each other without any gap. Since it hardens | cures or hardens | cures, electroconductive composition 3 'can be transcribe | transferred on the primer layer 2 without a transfer defect.

  In the above, what comprised mainly with electroconductive particle and binder resin as electroconductive composition 3 'was demonstrated. Such a conductive composition 3 'itself becomes the conductive pattern layer 3, but other conductive compositions may be applied in the present invention. For example, using a sol (dispersion) of an organometallic compound as the conductive composition 3 ′, for example, solidified by heating before and after the transfer step, and further baked as necessary to form a conductive pattern made of a conductive metal or metal compound. Layer 3 may be used. Further, for example, a known conductive resin such as polythiophene may be used as the conductive composition 3 ′, and the conductive pattern layer 3 itself may be used.

  The obtained conductive pattern layer 3 has (1) a form in which the interface 14 with the primer layer 2 is in a non-linear manner, and (2) a primer component contained in the primer layer 2 in the vicinity of the interface 14 with the primer layer 2. And (3) the conductive component constituting the conductive pattern layer 3 contains a primer component contained in the primer layer 2 in a form in which a region where the component constituting the conductive composition 3 ′ is mixed exists. It is formed in any one or more of the existing forms.

  The form (1) is a case where the interface is configured to be the interface 14 between the resin constituting the primer 2 and the resin or filler constituting the conductive pattern layer 3. The “filler” in this case is an arbitrary particle, and may be a conductor particle or a non-conductor particle. For example, when the conductive composition 3 ′ is composed of conductor particles and a binder resin, the interface 14 is a resin constituting the conductor particles, the binder resin, and the primer layer 2 in the conductive pattern layer 3. Are formed in a non-linear manner. The degree of intricacy at this time is influenced by the shape and size of the conductor particles. In addition, for example, when the conductive composition 3 ′ does not contain a filler and contains a conductive resin or a conductive compound, the primer layer 2 and the conductive layer 3 are electrically conductive by the pressure when the primer layer 2 is pressure-bonded in the recess. The interface 14 with the pattern layer 3 is intricate. Since the conductive pattern layer 3 has a configuration in which the interface 14 is in a non-linear manner, the adhesion between the primer layer 2 and the conductive pattern layer 3 is remarkably increased due to a so-called anchoring effect.

  In the form of (2), there is a region where the primer component contained in the primer layer 2 and the component constituting the conductive composition 3 ′ are mixed in the vicinity of the interface 14 between the primer layer 2 and the conductive pattern layer 3. It is a form that exists. At this time, the interface 14 may appear clearly, or the non-clear warm interface 14 may appear. The mixed region exists so as to sandwich the interface 14 vertically. In this case, a primer component (for example, a solvent) in the primer layer 2 and an arbitrary component (for example, a monomer component) in the conductive pattern layer 3 penetrate into each other. The mixed region may exist only on the upper side of the interface 14 or only on the lower side. As a case where the mixed region exists only on the upper side of the interface 14, the primer component in the primer layer 2 enters the conductive pattern layer 3, and any component in the conductive pattern layer 3 does not enter the primer layer 2. On the other hand, when the mixed region exists only below the interface 14, an arbitrary component in the conductive pattern layer 3 penetrates into the primer layer 2, and the primer component in the primer layer 2 becomes the conductive pattern layer. This is a case where it does not enter 3. Note that the thickness of the mixed region is not particularly limited. Since the conductive pattern layer 3 has a mixed region in the vicinity of the interface 14, the adhesion between the primer layer 2 and the conductive pattern layer 3 is remarkably high.

  The form (3) is a form in which the primer layer component contained in the primer layer 2 is present in the conductive composition 3 ′ constituting the conductive pattern layer 3. In this form, there are many cases where the primer component is large near the interface 14 and decreases toward the top portion. However, the embodiment is not particularly limited, and in short, the primer component exists in the conductive pattern layer 3. That's fine. The primer component may penetrate into the conductive pattern layer 3 to the extent that it is detected from the top of the conductive pattern layer 3, or may be detected to the vicinity of the interface 14. In the form of (3), in particular, when the region where the primer layer component is present in the conductive pattern layer 3 is localized in the vicinity of the interface 14, the mixed region in the form of (2) above. It can be said that this corresponds to a form that exists only above the interface 14. The conductive pattern layer 3 also has adhesion even if the conductive pattern layer 3 is formed on the mountain-shaped primer layer 2 that is not a flat surface in the first place, as in the cases of the above-described forms (1) and (2). In addition to being good, since the primer component has penetrated to the extent that it exists in the conductive pattern layer 3 as described above, the adhesion between the primer layer 2 and the conductive pattern layer 3 is remarkably increased.

In the form in which the conductive pattern layer has a mesh shape in particular (this form is also referred to as a convex mesh pattern layer or a conductive mesh (layer)), a line portion composed of two or more parallel line groups having different directions is formed. It intersects and is surrounded by these line parts to form an opening (pattern non-formation part). Even when three or more parallel line groups (line parts) cross, the basic design points and effects are the same. I will explain.
Further, the crossing angle of each line group, that is, the crossing angle θ between the first direction line part and the second direction line part can be selected from the range of 0 ° <θ <180 °, but θ = 90 ° is usually widely used. It has been.
In the mesh shape as the electrode film for a touch panel of the present invention, the light transmittance including the transparent substrate, the primer layer, the mesh opening, and the protective layer is preferably 70% or more, and preferably 80% or more. More preferred. The aperture ratio of the mesh is also determined from the above-mentioned range of 50 to 95% in consideration of the light transmittance.

(Electrical resistance reduction treatment process)
In addition, when the conductive pattern layer 3 itself formed as described above has an appropriate electrical resistance as a touch panel application, it is used as an electrode film for a touch panel.
However, when the electrical resistance of the formed conductive pattern layer 3 itself is higher than the appropriate electrical resistance for touch panel applications, the conductive composition 3 ′ is transferred from the recess to the transparent substrate through the primer layer. After the conductive pattern layer 3 is formed, the following electrical resistance reduction treatment steps (i) to (iii) are further performed.
(I) The treatment is performed in the presence of moisture and at a temperature higher than room temperature.
(Ii) Contact with acid.
(Iii) The above-mentioned processes (i) and (ii) are used together in order as appropriate.
By performing the electrical resistance reduction processing step, the volume resistivity of the conductive pattern layer is lowered. This phenomenon is observed particularly when the conductive particles are silver or particles containing silver.
Unlike the so-called baking treatment, this electrical resistance reduction treatment step is not a long-time heat treatment that damages a general film substrate such as PET, and nano-sized particles known as printing inks for low-temperature baking. Instead of this dispersion liquid, it is possible to use a conductive ink having general properties including a binder such as a resin.

In the electrical resistance reduction treatment step (i) in the presence of moisture at room temperature or higher, after the transfer (intaglio printing) step, the touch panel electrode film is in a state of higher temperature than room temperature in contact with moisture. Is allowed to stand for an appropriate time. The conditions in the presence of moisture may be left in air containing water vapor, sprayed (sprayed) with water particles in the form of mist or raindrops, or immersed in liquid water. In the case of leaving in air containing water vapor, the relative humidity of the left air (atmosphere) is 70% RH or more, preferably 85% or more. The temperature in such a high temperature state (atmospheric temperature when left in air containing water vapor, and water temperature when immersed in water) is 30 ° C. or higher, preferably 60 ° C. or higher. However, if the temperature is too high, the binder resin and the transparent base material may be altered or changed.
The treatment time is 48 hours after the start of treatment, and the surface resistance value decreases with time. However, after 48 hours, the treatment time is substantially constant, so it is preferable that the treatment time be about 48 hours.
By this electrical resistance reduction treatment process, the surface resistivity of the entire conductive pattern layer is reduced to about 80 to 50% before the treatment (the apparent volume resistivity is also about 80 to 50% before the treatment).

Next, the treatment with (ii) acid will be described. In the present invention, the treatment with acid means that the conductive composition layer is transferred from the inside of the intaglio recess to the transparent substrate via the primer layer to form a conductive pattern layer, and then contacted with an acid, thereby conducting the conductive pattern layer. Is a treatment for reducing the volume resistivity.
The acid in the present invention is not particularly limited, and can be selected from various inorganic acids and organic acids. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and the like. Examples of the organic acid include acetic acid, citric acid, succinic acid, propionic acid, lactic acid, and benzenesulfonic acid. These may be strong acids or weak acids. Acetic acid, hydrochloric acid, sulfuric acid, and an aqueous solution thereof are preferable, hydrochloric acid, sulfuric acid, and an aqueous solution thereof are more preferable. In the case of silver conductor particles, hydrochloric acid and an aqueous solution thereof are particularly preferable.

The treatment time with the acid is sufficient for several minutes or less, and even if the treatment time is made longer, the effect of improving the conductivity may not be increased or the effect of improving the conductivity may be deteriorated. The treatment time with the acid is preferably 15 seconds to 60 minutes, more preferably 15 seconds to 1 minute.
The method of treating with an acid is not particularly limited. For example, the conductive pattern layer is immersed in an acid or an acid solution, or an acid or an acid solution is applied on the convex pattern layer. A method of applying vapor of the solution to the conductive pattern layer or spraying (spraying) a mist or raindrop of acid or an acid solution is used. Among these methods, the method of bringing the conductive pattern layer into contact with the acid liquid, such as immersing the conductive pattern layer in an acid solution, or applying an acid or an acid solution on the conductive pattern layer, is effective. It is preferable because of its excellent improvement effect. That is, as the acid treatment conditions, it is preferable to immerse the convex conductive pattern layer in an acid solution at a temperature of 40 ° C. or lower, or to apply an acid or an acid solution onto the conductive pattern layer.

When an acid solution is used, the acid concentration is preferably 10 mol / L or less and 0.05 mol / L or more. If the concentration of the acid solution is too high, workability may deteriorate and productivity may deteriorate, or if a thermoplastic resin film is used as the transparent substrate, the transparent substrate will be whitened and transparent. Is unfavorable because it may damage the process. Moreover, since the effect of the process by an acid cannot be acquired when the density | concentration of an acid is too low, it is not preferable.
In addition, when using the solution of an acid, since there is a concern about the bad influence by the residue of an acid, it rinses after a process and a drying process is needed.

The reason why the volume resistivity is reduced by the electrical resistance reducing process is not yet understood at present, but is considered as follows.
For example, when silver is used as the conductor particles, the main cut surface at the time when the conductive pattern layer is formed by specific intaglio printing as shown in FIG. 6 is taken by SEM (scanning electron microscope) in FIG. is there. At this stage, some of the adjacent silver particles are in contact with each other leaving a boundary surface (a line in the cross section) between the particles, and the electrical conduction between the adjacent silver particles is ensured by the contact. . However, due to the contact resistance at the interface, the electrical resistance of the conductive pattern layer is relatively large.
On the other hand, FIG. 9 is an image obtained by photographing the main cut surface with an SEM after the conductive pattern layer in the state of FIG. Between adjacent silver particles, it is observed that the boundary between both particles disappears and the adjacent particles are fused. A decrease in the distance between each particle is also observed. For this reason, the contact resistance between the adjacent particles which are fused and integrated is eliminated, and the electric resistance is also reduced between the particles which are not fused and separated due to a decrease in the high resistance interparticle distance. These are presumed to be the direct causes of reduction in electrical resistance (volume resistivity or surface resistance).

(Filled bed)
The filling layer 9 can be arbitrarily provided in the opening 19 of the conductive mesh 3 as shown in FIG. By providing the filling layer 9 in the opening 19, the height (thickness Tc) of the conductive mesh 3 can be reduced, so that the conductor (conductive mesh or transparent conductive film) of the electrode film facing the conductive mesh 3. The strength of the conductive mesh 3 when in contact with can be increased. In addition, the thickness of the filling layer 9 should just be the thickness which the top part of the electroconductive mesh 3 is not hidden, for example, should just be about 40%-80% of the height of the electroconductive mesh 3. FIG.

  The material for forming the filling layer 9 is not particularly limited, but it is preferable to use the same material as the material for forming the primer layer 2 described above from the viewpoint of the adhesiveness of the opening 19 to the primer layer 2 and light transmittance. . The formation method of the filling layer 9 is not particularly limited, but the filling layer 9 is provided in such a manner that it does not ride on the top of the conductive mesh 3 by printing or applying a predetermined amount on the entire surface after the conductive mesh 3 is provided. Can do.

(Hard coat layer)
As shown in FIG. 1, the hard coat layer 4 is provided as necessary on a surface S <b> 2 on the opposite side to the formation surface S <b> 1 of the conductive mesh 3 of the transparent substrate 1. The surface on which the hard coat layer 4 is formed is the surface that comes into contact with the input pen or the like. By forming the hard coat layer 4 on the surface S2, the conductive mesh when the touch pen sliding durability test is performed. 3 breakage can be significantly reduced. As a characteristic of the hard coat layer 4 exhibiting such an action, it is preferable that the pencil hardness is 2H to 4H. In addition, a hard-coat layer generally means the thing which shows the hardness more than "H" in the pencil hardness test prescribed | regulated by JISK5600-5-4 (1999).
Known materials can be appropriately selected and applied for the material, thickness, manufacturing method and the like of the hard coat layer. As a typical one, for example, a coating film having a thickness of about 1 to 10 μm formed by curing a (meth) acrylate monomer, a prepolymer, or a mixture of a monomer and a prepolymer with ultraviolet rays or an electron beam. Is mentioned.

  Further, the hard coat layer 4 has a low coefficient of friction, and the input pen 40 preferably slides smoothly. The friction coefficient of the surface of the hard coat layer 4 is about 0.15 to 1.0, preferably 0.15 to 0.3. The friction coefficient measurement is obtained as a result of measurement with a Haydon surface property tester.

(Other layers)
The electrode film for a touch panel of the present invention may be provided with various known optical functional layers such as an antireflection layer and an antiglare layer as necessary.

[Touch panel]
The touch panel of the present invention is characterized in that the electrode film for a touch panel of the present invention is used as an electrode film on at least one side as a resistance film in a touch panel classified as a resistive film type according to the classification by operation principle. . The electrode film for a touch panel of the present invention is particularly effective for a resistive film analog detection type touch panel because the entire surface is a transparent conductive pattern layer of a resistive film. Specifically, the surface of the electrode film of the present invention on which the electrodes are arranged is opposed to each other by being insulatively bonded to each other at a predetermined interval G with a spacer interposed therebetween as shown in FIG. A four-wire resistive film analog detection touch panel that is a voltage detection method that applies voltage and converts the voltage at the contact point into a position, or a current detection method that detects the position from a current balance by passing a constant current through the electrodes. As an example.
Further, in the voltage detection method, an 8-wire resistive film analog detection method touch panel that can separate the voltage application electrode and the detection electrode and cancel the resistance component other than the detection resistor can be given as an example.
Furthermore, the resistance film is a non-voltage application side and a voltage application side, electrodes are arranged at the four corners of the resistance film on the voltage application side, and bonded in an insulated state, and a voltage is applied to each electrode. An example is a 5-wire resistive analog detection touch panel that is a voltage detection method that converts the voltage at the contact point into a position, or a current detection method that detects a position from a current balance by passing a constant current through the electrodes.
Further, in the voltage detection method, a 7-wire resistive film analog detection touch panel that can separate the voltage loading electrode and the detection electrode and cancel the resistance component other than the detection resistor can be given as an example.

  Examples will be described below, but the present invention is not limited to these examples.

Example 1
[Preparation of intaglio]
First, as the intaglio roll 62, a gravure printing cylinder having a line width of 18 μm, a line pitch of 270 μm, a lattice mesh pattern, and a target plate depth of 10 μm was prepared.

[Preparation of transparent substrate]
Next, as the transparent substrate 1, a long roll wound biaxially stretched transparent polyethylene terephthalate (PET) film having a width of 1000 mm and a thickness of 100 μm subjected to an easy adhesion treatment on one side was used. Moreover, the ultraviolet curable resin composition which consists of a urethane acrylate type prepolymer which added 1 mass% of stearic acid ester as a mold release agent was prepared. The PET film set in the supply section is fed out, and the UV curable resin composition is coated on the easy-adhesion treated surface of the PET film to a thickness of 14 μm by a slanted gravure reverse roll coat method, and is fluid in an uncured state. A transparent substrate formed by forming the primer layer 2 was prepared.

[Preparation of conductive composition (silver paste + carbon black)]
100 parts by mass of flaky silver particles having an average particle diameter of about 2 μm as conductor particles, 45 parts by mass of acetylene black (average particle diameter 35 nm) as carbon black, thermoplastic polyester urethane resin as binder resin, solvent Then, butyl carbitol monoacetate was further blended, sufficiently stirred and mixed, and then kneaded with three rolls to prepare a conductive composition.

[Manufacture of electrode films for touch panels]
An electrode film for a touch panel was produced using the apparatus shown in FIG. First, the conductive composition 15 (silver paste + carbon black) filled with the filling container 68 using the gravure plate roll 62 having a plate pattern of 18 μm in line width, 270 μm in pitch, and 10 μm in plate depth. ) A plate surface 63 in which ink is coated on a plate portion by a pick-up roll 61 and excess ink is scraped off by a doctor blade 65, and a transparent substrate 1 (PET film) on which a fluid primer layer 2 is formed in an uncured state. The primer layer 2 side is pressure-bonded with the nip roll 66, and then, while traveling between the ultraviolet irradiation zones (not shown, but present above the intaglio roll 62 in the portion indicated by “UV zone” in FIG. 7), After curing the UV curable resin of the primer layer by irradiating the UV light from the plate surface through the nip roll 67 3 were allowed to Hanareban was prepared the conductive pattern layer 3 ungated mesh shape by transferring the plate pattern of the plate cylinder surface via a primer layer 2 cured on a PET film, an electromagnetic wave shielding material. The transparent substrate was an endless roll, and was printed by a roll-to-roll method at a printing speed of 10 m / min.
Next, after printing, the electromagnetic wave shielding material is left in an atmosphere at a temperature of 80 ° C. and a relative humidity of 90% for 48 hours to perform a process for reducing electrical resistance, followed by a room temperature atmosphere (temperature 23 ° C., relative humidity 50 %).
By adding a release agent to the UV curable resin of the primer layer, the release property of the primer layer (UV curable resin) from the intaglio printing plate cylinder is improved, and the transfer amount of the conductive material from the intaglio is also increased. Improved, peel tension from plate cylinder decreased, and stable release at normal point P (see Fig. 7 (A)), reducing scattering of uncured conductive material and visually discriminating It was impossible. Further, no striped unevenness in the direction perpendicular to the traveling direction after UV curing was seen.
Further, no transition defects such as disconnection were observed in the transferred convex pattern. The thickness of the printed convex pattern (measured with reference to the primer layer of the non-mesh portion) is 9 μm, and the transition rate calculated by the ratio of the plate depth to the printing thickness is (mesh pattern thickness 9 μm / plate depth). 10 μm) × 100 = 90%, but in reality, there is a volume shrinkage due to solvent drying of the silver paste ink, so it is estimated that the transition is almost 100%.
Furthermore, the form of the interface between the primer layer 2 and the conductive pattern layer 3 had the above-described structure (1) in which the interfaces 14 with the primer layer 2 were alternately interleaved in a non-linear manner. As a result of magnifying and observing such an intricate structure with an electron microscope, the conductive particles (silver particles) in the conductive pattern layer are irregularly distributed up and down at the interface with the primer layer 2 to form the interface. It was recognized that The distribution of the conductive particles is found to be denser and denser as it goes to the top of the conductive pattern layer, and vice versa. It was. In the main cutting plane orthogonal to the mesh wire ridge, the number of conductor particles per unit cross-sectional area is 1 / μm ^{2 on} average in the portion adjacent to the primer layer, and 3 / μm ^{2 on} average near the top. Met.

The conductive pattern layer 3 after curing of the conductive composition has an electron micrograph of its cross section as shown in FIG. 9, and a part of the silver fine particles excluding the vicinity of the primer layer are adjacent to each other at a distance of 0. Between the particles of the silver particles in contact with each other, the interface disappears and is in a fused state. From this cross-sectional photograph, the distance between the conductor particles at the top of the conductive pattern layer 3 and the distance between the conductor particles in the vicinity of the interface with the primer layer were measured, and the respective averages were obtained. The distance was 0.5 μm (the minimum value among individual numerical values was 0 μm), and the average distance between the conductive bodies in the vicinity of the interface with the primer layer was 1.5 μm.
That is, the distribution of the conductive particles is sparse (coarse) densely distributed such that the distance between the particles decreases toward the top of the conductive pattern layer and conversely the distance between the particles increases toward the primer layer side. It was recognized that It is also recognized that two points separated by a maximum of 11 μm are connected in the width direction of the conductive pattern layer (left and right in FIG. 9) on the surface of the conductive pattern layer by the path of the fused silver particles. It was.

Subsequently, the surface (electrical) resistance of the obtained electrode film for touch panels was measured.
The measurement was performed in a room temperature atmosphere (temperature 23 ° C., relative humidity 50%). The surface resistivity was 700Ω / □. The light transmittance was 82%.

The electrode film for a touch panel of the present invention can be used for a resistive film type touch panel or the like.
The touch panel of the present invention can be effectively used as an input device mounted on the screen of a display device such as a liquid crystal display or a plasma display.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Primer layer 3 Conductive pattern layer 3 'Conductive composition 4 Hard coat layer 5 Easy adhesion layer 6 AR (antireflection) layer 7 Conductive mesh pattern part 8 Peripheral part 9 Filling layer 10, 10A, 10B, 10C , 10D electrode film 11 metal layer 12 spacer 13 dent 14 interface 19 between the primer layer and the conductive mesh 19 openings 20, 30 electrode film 21 on the display device side transparent substrate 23 transparent conductive film 40 human capen 50A, 50B touch panel 61 Pickup roll 62 Intaglio roll 63 Plate surface 64 Recess 65 Doctor blade 66 Nip roll 67 Nip roll 68 Filling container 100 Mobile phone A A portion where the conductive material layer is formed TA A thickness B A portion where the conductive material layer is not formed TB B thickness S Striped unevenness Cp Conductor particle G Scatter R Nda resin

Claims (3)

An electrode film for a touch panel having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer,
Of the primer layer, the portion where the conductive pattern layer is formed is thicker than the portion where the conductive pattern layer is not formed, and the conductive composition contains conductor particles and binder resin. The distribution of the conductive particles in the conductive pattern layer is relatively sparse in the vicinity of the primer layer and dense in the vicinity of the top of the conductive pattern layer. Electrode film for touch panel. An electrode film for a touch panel having a transparent substrate, a primer layer formed on the transparent substrate, and a conductive pattern layer made of a conductive composition formed in a predetermined pattern on the primer layer,
Of the primer layer, the portion where the conductive pattern layer is formed is thicker than the portion where the conductive pattern layer is not formed, and the conductive composition contains conductor particles and binder resin. The touch panel is characterized in that the distance between the conductive particles in the conductive pattern layer is relatively large in the vicinity of the primer layer and small in the vicinity of the top of the convex pattern layer. Electrode film.   It is a touch panel which makes each electrode surface of two electrode films oppose at a fixed space | interval, Comprising: The touchscreen electrode film of Claim 1 or 2 is used for the electrode film of at least one side, The touchscreen characterized by the above-mentioned.