JP2012201078A - Front filter for image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front filter 101 for an image display device, which includes a lamination structure having a conductive pattern layer 2 containing metal, wherein: other functional layer 4 formed thereon by using a photocurable resin composition is bonded through an adhesive layer 3; and the front filter is excellent in adhesiveness between the conductive pattern layer and the other functional layer, prevents discoloration by corrosion of the conductive pattern layer, and prevents yellowing of the adhesive layer.SOLUTION: The adhesive layer contains acrylic resin substantially containing no carboxyl group, a silane coupling agent, a benzotriazole compound, and hindered phenol antioxidant.

Description

  The present invention relates to a front filter for an image display device disposed on a viewer side of an image display body such as a plasma display panel.

Some image display devices such as a plasma display panel (referred to as PDP) and a cathode ray tube (referred to as CRT) generate electromagnetic waves, which cause electromagnetic noise interference (EMI). In particular, since PDP uses plasma discharge for light emission, unnecessary electromagnetic waves in the 30 MHz to 1 GHz band may leak to the outside and affect other devices (for example, remote control devices, information processing devices, etc.). . Therefore, a front filter including an electromagnetic wave shielding layer is provided on the front side (observer side) of the PDP.
In general, the front filter for PDP not only includes an electromagnetic wave shielding layer, but also has a plurality of other functional layers such as a near-infrared absorption layer, an antireflection layer, and a contrast enhancement layer to be multi-functional and highly functional. ing. As a method of laminating and integrating a plurality of functional layers, a method of joining via an adhesive layer is known.
For example, Patent Document 1 describes that an electromagnetic wave shielding layer and a contrast improving layer are bonded together via a transparent adhesive layer. In Patent Document 1, the contrast improving layer includes a lens portion and a light absorbing portion (paragraph 0022), and the lens portion can be formed of an ultraviolet curable resin composition or a thermoplastic resin composition. It is preferable to use a curable resin composition (paragraph 0023), and it is preferable to use an ionizing radiation curable resin as the transparent binder of the light absorbing portion (paragraph 0024).

In Patent Document 2, in a configuration in which an adherend layer is laminated on a copper mesh layer of an electromagnetic wave shielding sheet via an adhesive layer, an adhesive having an acid value such as an acrylic adhesive having a carboxyl group, and The use of a pressure-sensitive adhesive layer containing an antioxidant such as a benzotriazole antioxidant is described. In patent document 2, the adhesiveness of a copper mesh layer and a to-be-adhered body layer becomes high by using the adhesive which has an acid value. Moreover, although the adhesive which has an acid value corrodes copper and discolors the surface of a copper mesh layer and an adhesive layer in blue, in patent document 2, it originates in such corrosion of copper by antioxidant. Discoloration to blue is prevented.
Patent Document 3 (Japanese Patent Application Laid-Open No. 2006-15707) discloses a composite filter in which a functional film for an optical filter is bonded to a metal mesh pattern of an electromagnetic wave shielding sheet through an adhesive layer as a rust inhibitor. It describes that an adhesive layer containing an acrylic resin adhesive is used as a triazole compound and an adhesive.

JP 2007-272161 A JP 2007-95971 A JP 2006-15707 A

It was described in Patent Document 2 above when a conductive pattern layer containing a metal was provided as an electromagnetic wave shielding layer for the front filter, and a contrast improving layer as in Patent Document 1 was to be bonded thereon via an adhesive layer. By using a pressure-sensitive adhesive having such an acid value and a pressure-sensitive adhesive layer containing an antioxidant, excellent adhesion between the conductive pattern layer and other functional layers can be obtained, and the metal of the conductive pattern layer is corroded. This also prevented discoloration.
However, in this case, the rust caused by the migration of metal rust into the pressure-sensitive adhesive layer should have been eliminated, but the pressure-sensitive adhesive layer still turns yellow (yellowing). Occurred. As a result of intensive studies by the present inventors, when the lens part and the light absorbing part of the contrast improving layer are formed of an ultraviolet curable resin composition, residues such as a photopolymerization initiator and a monomer contained in the contrast improving layer are present. It is presumed that yellowing of the pressure-sensitive adhesive layer is caused by shifting to the pressure-sensitive adhesive layer and interacting with components in the pressure-sensitive adhesive layer. Furthermore, the metal contained in the conductive pattern layer moves to the pressure-sensitive adhesive layer, the residue contained in the contrast enhancement layer moves to the pressure-sensitive adhesive layer, and these interact with each other in the pressure-sensitive adhesive layer. It is speculated that the transition material from the pattern layer also interacts in the pressure-sensitive adhesive layer with the transition material from the contrast enhancement layer and the component forming the pressure-sensitive adhesive layer.
The present invention has been made in order to solve the above problems, and has a conductive pattern layer containing a metal in order to exert some function such as an electromagnetic wave shielding layer, and an ultraviolet curable resin composition on the conductive pattern layer. In a front filter for an image display device including a laminated structure in which other functional layers formed using a photocurable resin composition such as a product are joined via an adhesive layer, a conductive pattern layer and other functional layers It is an object of the present invention to provide a front filter that is excellent in adhesiveness, does not cause discoloration due to corrosion of a conductive pattern layer, and does not cause yellowing of an adhesive layer.

The front filter for an image display device of the present invention includes a laminated structure in which a functional layer obtained by curing a photocurable resin composition is bonded via a pressure-sensitive adhesive layer on a conductive pattern layer containing a metal.
The pressure-sensitive adhesive layer is formed using a pressure-sensitive adhesive composition containing an acrylic resin substantially free of carboxyl groups, a silane coupling agent, a benzotriazole-based compound, and a hindered phenol-based antioxidant. It is.

  The image display device of the present invention is characterized in that the front filter for an image display device of the present invention is arranged on the viewer side of the image display device body.

  According to the present invention, the pressure-sensitive adhesive layer that joins the conductive pattern layer containing metal and the functional layer obtained by curing the photocurable resin composition has excellent adhesion and is caused by rust of the conductive pattern layer. Since no discoloration occurs and no yellow discoloration occurs, a high-quality front filter for an image display device is provided.

FIG. 1 is a diagram schematically showing a cross section of a PDP in which a front filter for an image display device of the present invention is arranged on the viewer side of a PDP panel. FIG. 2 is a plan view of a conductive pattern layer included in the front filter for an image display device of the present invention. FIG. 3 is a diagram schematically showing a cross section of an example of the conductive pattern layer. FIG. 4 is a plan view of a contrast enhancement layer included in the front filter for an image display device of the present invention. FIG. 5 is a diagram illustrating a configuration example of an apparatus for forming a conductive pattern layer.

In the present invention, (meth) acrylate represents acrylate and / or methacrylate.
In the present invention, the molecular weight means a weight average molecular weight which is a polystyrene equivalent value measured by gel permeation chromatography (GPC) in a THF solvent when having a molecular weight distribution, and when having no molecular weight distribution, It means the molecular weight of the compound itself.
According to the definition of film and sheet in JIS K6900, the sheet is thin and generally refers to a flat product whose thickness is small relative to the length and width, and the film is extremely small compared to the length and width. A thin, flat product with an arbitrarily limited maximum thickness, usually supplied in the form of a roll. Therefore, it can be said that a film with a particularly thin thickness among the sheets is a film, but the boundary between the sheet and the film is not clear and is difficult to distinguish clearly. Is defined as “sheet”.
The light of the present invention includes not only electromagnetic waves having a wavelength in the visible region but also electromagnetic waves having a wavelength in a non-visible region such as ultraviolet rays and X-rays, which are collectively referred to as ionizing radiation.

The front filter for an image display device of the present invention includes a laminated structure in which a functional layer obtained by curing a photocurable resin composition is bonded via a pressure-sensitive adhesive layer on a conductive pattern layer containing a metal.
The pressure-sensitive adhesive layer is formed using a pressure-sensitive adhesive composition containing an acrylic resin substantially free of carboxyl groups, a silane coupling agent, a benzotriazole-based compound, and a hindered phenol-based antioxidant. It is.

Conventionally, as an adhesive component of an adhesive layer used for a front filter for an image display device, an acrylic resin having an acid value, that is, a carboxyl group has been used, but a functional layer obtained by curing a photocurable resin composition It is considered that when this residue moves into the pressure-sensitive adhesive layer, it interacts with an acrylic resin having an acid value to cause yellowing.
Therefore, in the present invention, by using an acrylic resin that does not substantially contain a carboxyl group as an adhesive component of the adhesive layer, and further blending a benzotriazole compound and a hindered phenol antioxidant into the adhesive layer, Prevent or reduce yellowing of the adhesive layer.
However, when an acrylic resin that does not substantially contain a carboxyl group is used as the adhesive component of the adhesive layer, sufficient adhesive performance cannot be obtained. Therefore, in the present invention, a silane coupling agent is blended in the pressure-sensitive adhesive layer together with an acrylic resin that does not substantially contain a carboxyl group, so that it is sufficient between the conductive pattern layer containing a metal and another functional layer. To ensure good adhesion.

FIG. 1 is a cross-sectional view schematically showing an example of an embodiment of the present invention. This embodiment will be used as a representative example and the description will be continued below.
FIG. 1 shows a state in which a front filter (101) for an image display device is arranged on the viewer side of a PDP panel (102) that is a main body of the image display device. The front filter (101) for the image display device is disposed on the viewer side of the PDP panel (102) via an air layer, but may be attached to the surface of the PDP panel (102).
The front filter (101) for an image display device is provided with a conductive pattern layer 2 containing a metal as an electromagnetic wave shielding layer on a transparent substrate 1, and a contrast improving layer 4 is bonded thereon via an adhesive layer 3. Has a laminated structure. A primer layer 5 is interposed between the transparent substrate 1 and the conductive pattern layer 2.
In order to manufacture the front filter (101) for an image display device, a sheet-like member in which the conductive pattern layer 2 is formed on the transparent substrate 1 and a sheet-like member having a structure of a contrast improving layer are prepared. , They are joined by the adhesive composition.
The present invention can be widely applied to a case where a layer obtained by curing a photocurable resin composition on a conductive pattern layer is to be bonded via an adhesive layer. The conductive pattern layer may be expected to exhibit a function other than electromagnetic shielding, and the other functional layer bonded on the conductive pattern layer is obtained by curing the photocurable resin composition. As long as the functional layer is formed, any function other than the improvement in contrast may be exhibited.

<Transparent substrate>
The transparent substrate 1 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as transparency (light transmittance) in the visible light region, heat resistance, and mechanical strength, such as glass and ceramics. A plate-like rigid body such as a transparent inorganic plate or a resin plate may be used. However, a flexible resin film (or sheet) is preferable in consideration of suitability for continuous processing with a roll-to-roll having excellent productivity. The roll-to-roll refers to a processing method in which the material is unwound and supplied from a winding (roll), appropriately processed, and then wound and stored in the winding.

Examples of the resin used as a material for the resin film and the resin plate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), ethylene glycol-1,4 cyclohexanedimethanol-terephthalic acid copolymer, ethylene glycol-terephthalic acid- Polyester resins such as isophthalic acid copolymers, polyester thermoplastic elastomers, acrylic resins such as polymethyl methacrylate, polyolefin resins such as polypropylene and cycloolefin polymers, cellulose resins such as triacetyl cellulose, polycarbonate resins Etc. Among these, a polyethylene terephthalate biaxially stretched film is a preferable transparent substrate in terms of heat resistance, mechanical strength, light transmittance, cost, and the like.
Examples of the transparent inorganic material include soda glass, potash glass, borosilicate glass, lead glass, and other transparent ceramics such as PLZT and quartz.

  The thickness of the transparent substrate is basically not particularly limited and can be appropriately selected depending on the application. When utilizing a flexible resin film, it is 12-500 micrometers, for example, Preferably it is about 25-200 micrometers. When using a resin or transparent inorganic plate, for example, it is about 500 to 5000 μm.

<Conductive pattern layer containing metal>
Even if the conductive pattern layer 2 containing a metal itself is opaque, the presence of an opening between the conductive lines makes it possible to achieve some function such as electromagnetic shielding performance and light transmittance. Yes.
FIG. 2 is a plan view of the conductive pattern layer 2 of FIG. 1 as viewed from the viewer side. The conductive pattern layer 2 is composed of a conductive line 2a arranged in a lattice pattern and a square opening 2b partitioned by the conductive line as a frame, and a mesh shape in which the openings 2b are densely arranged. is there. A ground pattern 8 is provided around the conductive pattern layer 2.

The pattern shape of the conductive line is typically a mesh (mesh or lattice) shape, but other shapes such as a stripe (parallel line group or stripe pattern) shape, a spiral shape, and the like are also used. In the case of a mesh shape, the unit cell shape may be a triangle such as a regular triangle or an unequal side triangle, a square such as a square, rectangle, trapezoid or rhombus, a polygon such as a hexagon or octagon, a circle or an ellipse. Used. In addition, for the purpose of reducing moire, a random mesh pattern or a pseudo-random mesh pattern can be used.
The width of the conductive line and the pitch between the lines may be dimensions that are usually employed. For example, the line width can be 5 to 50 μm, and the line-to-line pitch can be 100 to 500 μm. The line width is preferably 30 μm or less, particularly preferably 20 μm or less, from the viewpoint of miniaturization in order to obtain a more transparent material. The aperture ratio (ratio of the total area of the openings in the total area of the conductive pattern layer) is usually about 50 to 95%.
In some cases, a ground pattern such as an adjacent solid (a layer having no opening) or the like is provided on the entire circumference or a part of the periphery of the conductive pattern layer while maintaining conduction with the conductive pattern layer. This ground pattern may be formed simultaneously with the formation of the conductive pattern layer, or may be formed separately. When the ground pattern is separately formed, it may be printed using conductive ink, or may be formed by attaching a conductive metal tape or the like.
The conductive pattern layer may include a layer that assists the function of the conductive pattern layer, such as a blackening layer or a rust prevention layer, as necessary.

Although the formation method of a conductive pattern layer is not specifically limited, For example, the following four methods are mentioned.
(1) Thickness (line height) to have a predetermined pattern shape for ensuring sufficient transparency by the intaglio printing method using conductive ink or conductive paste and exhibit sufficient electromagnetic shielding performance A conductive line is formed.
(2) A method in which conductive ink is printed on a transparent substrate in a predetermined pattern, and metal plating is performed on the patterned conductive ink layer (for example, JP-A-2000-13088).
(3) A conductive ink or a chemical plating catalyst-containing photosensitive coating solution is applied to the entire surface of the transparent substrate, the coating layer is formed into a predetermined pattern by a photolithography method, and then a metal is applied onto the patterned coating layer. Method of plating (for example, Sumitomo Osaka Cement Co., Ltd., New Materials Division, New Materials Research Institute, New Materials Research Group, “Photoresolvable Chemical Plating Catalyst”, [online], date not listed, Sumitomo Osaka Cement Co., Ltd. [Search January 7, 2003], Internet <URL: http://www.socib.com/product/hproduct/display.html>).
(4) After laminating a transparent base material and a metal foil with an adhesive, the metal foil is formed into a predetermined pattern by a photolithography method (for example, JP-A-11-145678).
(5) A conductive substrate is formed on one surface of the transparent substrate, and a transparent substrate on which a metal layer is formed as a metal plating layer by electrolytic plating is prepared. The plating layer and the conductive treatment layer are formed into a predetermined pattern by a photolithography method (for example, JP-A-2003-86991).

In particular, in the present invention, a primer layer is formed on the surface of the transparent substrate, and an intaglio printing method is performed using a conductive ink or conductive paste on the primer layer in a state where the primer layer maintains fluidity. It is preferable to form a conductive pattern layer having a predetermined pattern by a method to be performed (so-called drawing primer intaglio printing method).
<Pulling primer intaglio printing method>
(Composition for primer layer)
The primary purpose of the primer layer is to improve the transferability of the ink (composition for conductive layer) from the intaglio to the printed material (transparent substrate) when the conductive pattern layer is printed. This is a layer for improving the adhesion between the substrate and the substrate. That is, both the transparent substrate and the conductive pattern layer have good adhesion, and are also a transparent layer for ensuring light transmittance of the opening (line non-formation part).
Furthermore, the primer layer is a layer that is provided on a transparent substrate in a state where fluidity can be maintained, and is formed as a layer that is solidified from a liquid while in contact with the intaglio during intaglio printing. It is a layer that is solidified when the layer is formed.

As a material constituting the primer layer, a thermoplastic resin, an ionizing radiation curable resin, or the like can be used.
Examples of the thermoplastic resin include acrylic resins such as polymethyl methacrylate (PMMA), vinyl chloride-vinyl acetate copolymers, polyester resins, and polyolefin resins.
In the present invention, a layer formed by coating and curing (solidifying) an ionizing radiation curable composition containing a liquid (fluid) ionizing radiation polymerizable compound in an uncured state is suitably used.
As the ionizing radiation polymerizable compound, monomers and / or prepolymers that are polymerized and cured by a reaction such as crosslinking with ionizing radiation are used.

Examples of such monomers include radically polymerizable monomers such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) ) Monofunctional (meth) acrylates such as acrylate, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) a Polyfunctional (meth) acrylates of various (meth) acrylates such relations and the like.
Examples of the cationic polymerizable monomer include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, 4-hydroxybutyl vinyl ether And vinyl ethers, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane.
Such prepolymers (or oligomers) include, for example, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate, and silicon (meth) acrylate as radical polymerizable prepolymers. And various (meth) acrylate prepolymers such as polythiol prepolymers such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. In addition, examples of the cationic polymerizable prepolymer include novolac epoxy resin prepolymer and aromatic vinyl ether resin prepolymer.

When ultraviolet rays or visible rays are used as the ionizing radiation, a photopolymerization initiator is usually added to the primer layer composition (the ionizing radiation curable composition in this case is referred to as a photocurable composition). To do).
When peeling after the primer layer is cured on the surface of the intaglio, a release agent may be added to the primer layer composition so that the force required for peeling from the plate surface (peeling force) is reduced and the primer layer is peeled off smoothly. . Examples of the release agent for the primer layer include higher fatty acid esters of mono- or polyhydric alcohols, phosphate esters, silicone resin release agents, fluororesin release agents, and the like.
The primer layer composition may contain a solvent, but in that case, a drying step is required after coating. Therefore, in view of cost, an ionizing radiation curable composition containing no solvent (non-solvent type or solvent-free) Type).

(Composition for forming conductive pattern layer)
The conductive pattern layer is prepared by applying a conductive layer composition (conductive ink or conductive paste) containing conductive particles and a binder resin onto the primer layer by an intaglio printing method disclosed in WO2008 / 149969. It can be obtained by printing in a pattern.
The conductive particles constituting the composition for the conductive layer include particles of low resistivity metal such as gold, silver, platinum, copper, nickel, tin, and aluminum, or high resistivity metal particles and resin as core particles. Examples thereof include particles, particles whose surfaces such as non-metallic inorganic particles are coated with a low resistivity metal such as gold and silver, graphite particles, conductive polymer particles, and conductive ceramic particles.
The shape of the conductive particles can be selected from various polyhedron shapes such as a regular polyhedron shape, a truncated polyhedron shape, a spherical shape, a spheroid shape, a scale shape, a disc shape, a dendritic shape, and a fibrous shape. In particular, a polyhedral shape, a spherical shape, or a spheroid shape is preferable. These materials and shapes may be appropriately mixed and used.
Since the size of the conductive particles is arbitrarily selected depending on the type, it cannot be specified unconditionally, but those having an average particle diameter of about 0.01 to 10 μm can be preferably used. In order to reduce the electric resistance of the resulting convex pattern layer and obtain good electromagnetic wave shielding properties, the average particle size is preferably smaller, and from this viewpoint, the average particle size is preferably 0.1 to 1 μm.

As the binder resin constituting the composition for the conductive layer, any of thermosetting resins, ionizing radiation curable resins, and thermoplastic resins can be used. Examples of the thermosetting resin include resins such as melamine resin, polyester-melamine resin, epoxy-melamine resin, phenol resin, polyimide resin, thermosetting acrylic resin, thermosetting polyurethane resin, and thermosetting polyester resin. Examples of the ionizing radiation curable resin include those described above as the primer material, and these may be used alone or in combination of two or more. Examples of the thermoplastic resin include thermoplastic polyester resins, polyvinyl butyral resins, thermoplastic acrylic resins, thermoplastic polyurethane resins, vinyl chloride-vinyl acetate copolymers, and the like. A mixture of two or more types is used. In addition, when using a thermosetting resin, you may add a curing catalyst as needed. When using an ionizing radiation curable resin, a photopolymerization initiator may be added as necessary.
In addition, it is sufficient for the mass ratio of the conductive particles and the binder resin in the composition for the conductive layer to be in the range of (conductive particles) / (binder resin) = 60/40 to 97/3. In view of the properties (electromagnetic shielding properties), printability, and strength of the conductive pattern layer, it is preferable.

In order to impart fluidity suitable for filling the recesses of the plate to the composition for the conductive layer, these resins are usually dissolved in a solvent and used in the form of a paste. The solvent of the conductive paste is not particularly limited, and can be used by appropriately selecting from the solvents generally used for printing inks, but it inhibits the stable curing of the primer layer or swells and whitens the cured primer layer Those which are not dissolved are preferred. The content of the solvent at the time of application to the intaglio recess is usually about 10 to 70% by mass, but is preferably as small as possible within a range where necessary fluidity can be obtained. However, when applying the intaglio printing method disclosed in WO2008 / 149969, in order to obtain sufficient transferability and sufficient adhesion between the conductive pattern layer and the primer layer, in the composition for the conductive layer, It is preferable to contain about 0.01 to 10% by mass of a solvent at the time of transfer from the plate recess.
In addition, in order to improve the fluidity and stability of the composition for the conductive layer, as long as it does not adversely affect the conductivity and adhesion with the primer layer, a filler, thickener, antistatic agent, surface activity An agent, antioxidant, dispersant, anti-settling agent, etc. may be added.

(Intaglio printing procedure)
First, the said primer layer composition is apply | coated to the one surface side of a transparent base material, and a primer layer is formed.
Next, the composition for conductive layers is transferred to the surface of the transparent substrate on which the primer layer is formed by a method of intaglio printing in a predetermined pattern.
FIG. 5 is a schematic configuration diagram of an apparatus for performing a transfer process by intaglio printing. The apparatus in FIG. 5 is centered on a gravure plate roll 10 provided with an intaglio on the side of the plate cylinder, and around the container 11, a pick-up roll 12, a doctor blade 13, a first nip roll having a conductive layer composition 17 stored therein. 14, the ionizing radiation irradiation zone 15 and the second nip roll 16 are provided.

  In the apparatus of FIG. 5, the pick-up roll 12 is rotated in accordance with the rotation of the gravure plate roll 10, and the conductive layer composition 17 in the container 11 is filled into the concave portion of the plate surface by the pick-up roll. Excess conductive layer composition deposited on the plate surface is scraped off by the doctor blade 13 to leave only the conductive layer composition in the recesses. The plate surface that has passed through the position of the doctor blade and the primer layer side of the transparent substrate 18 on which the primer layer is formed are pressure-bonded by the first nip roll 14.

At the time of pressure bonding, the primer layer is pressure bonded to the plate surface while maintaining fluidity. The “state in which the primer layer retains fluidity” as used in the present invention refers to a property or state in which the primer layer flows (deforms) due to pressure when the primer layer is pressure-bonded to the plate surface filled with the composition for the conductive layer. It is not necessary to have a low viscosity. Further, it is not always necessary to have Newtonian viscosity, and it may have non-Newtonian viscosity such as thixotropic property or dilatancy property.
The fluidity state of such a primer layer is such that, when an ionizing radiation curable resin is used as the resin for the primer layer, an ionizing radiation curable ink is applied on the transparent substrate, and the primer layer is in an uncured state. It is obtained only by maintaining.
In addition, when a thermoplastic resin composition is used as the primer layer resin, after the thermoplastic resin composition is applied onto the transparent substrate, it becomes fluid when it is pressure-bonded to the plate surface (for example, And about 50 ° C. to 200 ° C.).

When the primer layer is an ionizing radiation curable resin composition, the primer layer is cured while passing through the ionizing radiation irradiation zone 15 after passing through the position of the first nip roll 14. When the primer layer is a thermoplastic resin composition, after passing through the position of the first nip roll 14, the temperature of the primer layer is lowered to solidify.
And after a primer layer hardens | cures or solidifies and loses fluidity | liquidity, by peeling a transparent base material from a plate surface with the 2nd nip roll 16, the composition for electrically conductive layers is made into a predetermined pattern shape on the primer layer of a transparent base material. Transcript.
When a curable resin such as a thermosetting resin or ionizing radiation curable resin is used as the composition for the conductive layer, the conductive pattern layer is formed by peeling the transparent substrate from the plate surface and then performing a curing treatment. Is obtained.

FIG. 3 schematically shows a cross section orthogonal to the extending direction of the line portion constituting the conductive pattern layer formed by the drawing primer intaglio printing method, that is, the main cut surface.
When the conductive pattern layer is formed by the drawing primer intaglio printing method, the thickness (height from the surface of the primer layer to the top of the conductive line 2a) T is about 2 μm to 50 μm. Is preferred.
Moreover, the thickness Tp of the primer layer 5 is set to about 1 μm to 10 μm after curing. When the drawing primer intaglio printing method is performed, the thickness Tp ′ of the primer layer at a position immediately below the conductive line 2a is about 1 to 5 μm thicker than the thickness T at other positions.
In FIG. 3, the interface between the conductive line 2 a and the primer layer 5 is clear, but the cross-sectional form of this interface may be irregularly mixed or may be indistinct due to compatibility.
The conductive pattern layer preferably has a surface resistivity (simply abbreviated as surface resistance) of 0.8Ω / □ or less from the viewpoint of obtaining a sufficient electromagnetic wave shielding effect.

<Functional layer obtained by curing photocurable resin composition>
The other functional layer bonded on the conductive pattern layer may exhibit any function, and examples thereof include a contrast improving layer, a near infrared absorption layer, an antireflection layer, and an antiglare layer. be able to.
Examples of the photocurable resin to be blended in the photocurable resin composition for forming the functional layer include UV curable photocurable resins obtained by adding a photopolymerization initiator to an ionizing radiation curable resin. Applicable ionizing radiation curable resins include, for example, those listed as materials for the primer layer.
The photo-curable resin particularly suitable for the contrast improving layer will be described in detail again.

(Contrast improvement layer)
In the embodiment of FIG. 1, the contrast enhancement layer 4 corresponds to a functional layer obtained by curing a photocurable resin composition.
The contrast enhancement layer having such a configuration efficiently absorbs external light incident on the front filter from the viewer side, and efficiently emits the image light generated by the image display device to the viewer side. This layer exhibits the function of improving contrast.
The cross section of the contrast improving layer 4 having the configuration shown in FIG. 1 has a light transmission part (transparent resin part) 6 that emits image light and a light absorption part (black resin part) 7 that absorbs external light and stray light. The light transmission parts 6 and the light absorption parts 7 are alternately arranged. The external light that affects the contrast is in the visible region (generally 380 nm to 780 nm).
FIG. 4 is a plan view of the contrast enhancing layer 4 included in FIG. 1 as viewed from the PDP panel (102) side. The stripe-shaped light transmitting portions 6 and light absorbing portions 7 are arranged alternately and in parallel. A so-called micro louver structure is formed.

The contrast enhancement layer 4 is continuous in a straight line in a predetermined direction along the surface direction of the layer (front and back surfaces or an arbitrary direction in a plane parallel to the surface), and a cross section (main cut surface) perpendicular to the extending direction. Has a light-transmitting part 6 having a trapezoidal shape with the wide bottom base facing the viewer side, and is linearly connected in a direction parallel to the light transmission part, and the main cutting surface faces the wide bottom base to the PDP side. A PDP image light transmitting surface is provided, which is formed by alternately engaging a plurality of light absorbing portions 7 having a wedge-shaped shape.
In addition, the arrangement in which a large number are alternately meshed means that a large number of light transmitting portions and light absorbing portions are alternately adjacent to each other to form a part of the other. Further, the transmission surface of the PDP image light is not limited to the interface of the layers, and has a certain thickness.

As a method for forming the light transmitting portion 6, there are a hot pressing method in which a heated mold is pressed against a thermoplastic resin, a casting method in which a thermoplastic resin composition is injected into the mold and solidified, an injection molding method, a photocuring method. A conventionally known method such as a photocuring method in which a mold resin composition is injected into a mold and cured with ultraviolet rays or the like is used.
Among these methods, a photocuring method excellent in mass productivity is more preferable. The photocuring method can be produced by continuously embossing the unit of the light transmission part using a roll-shaped mold while supplying a continuous sheet.

The photocurable resin composition for forming the light transmission part contains a photocurable resin and a photopolymerization initiator. As such a photocurable resin composition, for example, a photocurable resin composition containing a photocurable prepolymer (P1), a reactive dilution monomer (M1), and a photopolymerization initiator (S1) is preferably used. It is done.
Examples of the photocurable prepolymer (P1) include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.
Examples of the reactive dilution monomer (M1) include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.
Examples of the photopolymerization initiator (S1) include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoyl Formate compounds (such as methylbenzoylformate), thioxanthone compounds (such as isopropylthioxanthone), benzophenones (such as benzophenone), phosphate compounds (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-) Trimethylbenzoyl) -phenylphosphine oxide and the like, and benzyldimethyl ketal and the like. Among these, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) are preferable from the viewpoint of preventing coloring of the light transmitting portion. ) -Phenylphosphine oxide.
In addition, the said photoinitiator (S1) shall be contained 0.5 mass% or more and 5.0 mass% or less on the basis (100 mass%) of the resin composition whole quantity for forming a light transmissive part. Is preferred.
If necessary, in the resin composition for the light transmitting part, various additives such as silicone additives and rheology control agents may be used to improve the coating film, improve coating properties, and release from the mold. It is also possible to add a defoaming agent, a release agent, an antistatic agent, an ultraviolet absorber and the like.

A wedge-shaped groove is formed at the same time as the light transmission portion 6 is formed. By filling the wedge-shaped groove with ink containing light absorbing particles and a binder and curing, the light absorbing portion 7 having a structure in which the light absorbing particles are dispersed in a matrix made of the binder is formed.
Although what is used as the said binder is not specifically limited, For example, the photocurable resin composition which mix | blended the photocurable prepolymer (P2), the reactive dilution monomer (M2), and the photoinitiator (S2) is used preferably. It is done.
Examples of the photocurable prepolymer (P2) include urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate.
Examples of the reactive dilution monomer (M2) include monofunctional monomers such as N-vinyl pyrrolidone, N-vinyl caprolactone, vinyl imidazole, vinyl pyridine, styrene, and other vinyl monomers, lauryl (meth) acrylate, stearyl ( (Meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) ) Acrylate, nonylphenoxy polyethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) a (Meth) acrylic acid ester monomers such as relate, cyclohexyl (meth) acrylate, benzyl methacrylate, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylate, acryloylmorpholine, A (meth) acrylamide derivative is mentioned. Polyfunctional monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polytetra Methylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate Bisphenol A polypropoxydiol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, glyceryl tri (meth) acrylate, propoxylated glyceryl tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate And dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.
Examples of the photopolymerization initiator (S2) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane- Examples include 1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.
Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. In the present invention, the amount of the photopolymerization initiator (S2) contained in the photocurable resin composition is based on the total amount of the photocurable resin composition from the viewpoint of curability and cost of the photocurable resin composition (100 mass). %) Is preferably included in an amount of 0.5% by mass or more and 10.0% by mass or less.
These photocurable prepolymer (P2), reactive diluent monomer (M2) and photopolymerization initiator (S2) can be used alone or in combination of two or more.
Specifically, a photopolymerizable component (specifically, photocurable prepolymer and reactive dilution monomer) composed of urethane acrylate, epoxy acrylate, tripropylene glycol diacrylate and methoxytriethylene glycol acrylate, refractive index and viscosity. Considering it, it can mix | blend arbitrarily and can be used.
In addition, you may add a silicone, an antifoamer, a leveling agent, a solvent, etc. to a photocurable resin composition as an additive.

The light-absorbing particles are contained in the composition that forms the light-absorbing part. When the light-absorbing part is configured, the light-absorbing part is composed of external light (light that enters the front filter from the viewer side) and stray light (light that wanders in the contrast improving layer ) To absorb.
The color of the light-absorbing particles, that is, the light-absorbing portion is preferably a low-lightness achromatic color such as black or gray from the viewpoint of not affecting the hue of the image. It can also be a chromatic color with low brightness such as brown, rosy, dark green, and dark purple.
As the light-absorbing particles, light-absorbing colored particles such as carbon black are preferably used. However, the light-absorbing particles are not limited to these, and colored particles that selectively absorb a specific wavelength according to the characteristics of image light. May be used. Specific examples include pigments such as carbon black, graphite and black iron oxide, dyes such as aniline black, resin fine particles colored with pigments, colored glass beads, and the like.
Such colored particles are usually contained in the above-mentioned photocurable resin composition in the range of 3% by mass to 30% by mass. Colored particles having an average particle size of 1.0 μm or more and 20 μm or less are used.

<Adhesive layer>
The pressure-sensitive adhesive is a kind of adhesive. Among the adhesives, the adhesive can be bonded only with the adhesiveness of the surface only by pressurization that is only moderate and usually lightly pressed by hand. Say things. In order to develop the adhesive strength of the pressure-sensitive adhesive, usually, physical energy or action such as heating, humidification, radiation (ultraviolet ray, electron beam, etc.) irradiation is unnecessary, and chemical reaction such as polymerization reaction is also unnecessary. In addition, the pressure-sensitive adhesive can maintain the adhesive strength to the extent that it can be re-peeled after bonding.
In the present invention, the pressure-sensitive adhesive layer 3 is formed using a pressure-sensitive adhesive composition containing at least the following components.
(1) Acrylic resin substantially free of carboxyl group (2) Silane coupling agent (3) Benzotriazole compound (4) Hindered phenol antioxidant

In the present invention, from the viewpoint of preventing yellowing, an acrylic resin that substantially does not contain a carboxyl group is used among the acrylic resins.
The acrylic resin is a polymer containing at least a (meth) acrylic acid alkyl ester monomer, and the proportion of the (meth) acrylic alkyl ester monomer is 30 to 99.5 parts by weight in 100 parts by weight of the acrylic resin. It is preferably copolymerized with.
As the adhesive resin, generally, a homopolymer or copolymer of a (meth) acrylic acid alkyl ester monomer having an alkyl group having about 1 to 18 carbon atoms is used. In the present invention, a carboxyl group is used. Since the acrylic resin which does not contain substantially is used, the monomer which has a carboxyl group can contain only the small quantity which becomes in the tolerance | permissible_range (less than 25 ppm as mentioned later) of a carboxyl group.

  Examples of (meth) acrylic acid alkyl ester monomers used here include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, sec-propyl (meth) acrylate, N-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, Examples thereof include n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, undecyl (meth) acrylate and lauryl (meth) acrylate.

The acrylic resin substantially free of carboxyl groups means that the content of carboxyl groups in the acrylic resin (polymer) is less than 25 ppm.
Here, the measuring method of carboxyl group content in acrylic resin can be measured with a nuclear magnetic resonance apparatus (NMR). Specifically, a carboxyl group and a silylating agent are reacted, and a peak derived from a silylated product is measured by 1H-NMR (600 MHz). The lower limit of quantification by this measuring method is 25 ppm. Therefore, when a carboxyl group is not detected by this method, it is determined that a carboxyl group is not substantially contained.

The weight average molecular weight of the acrylic resin substantially not containing a carboxyl group is preferably in the range of 200,000 to 800,000.
SK1811L (Soken Chemical Co., Ltd.) is mentioned as a commercial item of the acrylic resin which does not contain a carboxyl group substantially.

The silane coupling agent is used to reinforce the adhesion performance or the adhesion performance because the adhesion performance with the conductive pattern layer containing a metal is insufficient only with an acrylic adhesive that does not substantially contain a carboxyl group. .
Examples of the silane coupling agent include silane monomer, vinyl silane, methacryl silane, epoxy silane, mercapto silane, sulfur silane, amino silane, ureido silane, isocyanate silane, etc., especially for acrylic resins, amino silane, epoxy silane, methacryl Silane, mercaptosilane, and isocyanasilane are preferably used.
A 50 (Soken Chemical Co., Ltd.) is mentioned as a commercial item of a silane coupling agent.

  A benzotriazole-based compound is used for preventing yellowing. Examples of the benzotriazole-based compound include a compound containing at least the structure of the following formula (1) as a skeleton, and a sodium salt, potassium salt, and amine salt thereof. Examples of the substituent that may be included in the structure of the following formula (1) include an alkyl group that may have a substituent, an aryl group that may have a substituent, and a halogen atom. It is done.

Specifically, 1,2,3-benzotriazole (1H-benzotriazole), 1H-benzotriazole sodium salt, 4-methyl-1H-benzotriazole, 5-methyl-1H-benzotriazole, tolyltriazole (4- A mixture of methyl-1H-benzotriazole and 5-methyl-1H-benzotriazole), 4-methyl-1H-benzotriazole potassium salt, 5-methyl-1H-benzotriazole potassium salt, 4-methyl-1H-benzotriazoleamine Salt, 5-methyl-1H-benzotriazoleamine salt, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl) -2-hydroxyphenyl) benzotriazole and the like.
Among these, 1,2,3-benzotriazole (1H-benzotriazole), 4-methyl-1H-benzotriazole, 5-methyl-1H-benzotriazole, tolyltriazole (4-methyl / 5-methyl mixture) Is preferred.

  A commercially available product of 1H-benzotriazole is TH-BTA (Johoku Chemical Industry Co., Ltd.), and a commercially available product of tolyltriazole is TT-R (Cipro Kasei Co., Ltd.).

  The hindered phenol antioxidant is used for preventing yellowing, and is appropriately selected from compounds having a hindered phenol structure represented by the following structural formula.

  Among the hindered phenol antioxidants, compounds having a hindered phenol structure and a hydrazine structure are preferable because they are particularly excellent in yellowing prevention action.

  Usually, a hindered phenol-based antioxidant is a multimer of about 2 to 4 mer and has a molecular weight of 5000 or less, but there is no particular limitation regarding molecular size such as molecular weight or multimer.

Examples of commercially available hindered phenol antioxidants include the following products of BASF Japan Ltd. Among these, IRGANOX MD1024 is a compound having a hindered phenol structure and a hydrazine structure, and is preferably used.
IRGANOX MD1024 (generic name: 1,2-di [-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, molecular weight: 553)
IRGANOX 1010 (generic name: pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], molecular weight: 1178)
IRGANOX 1035 (generic name: thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], molecular weight: 643)
IRGANOX 1098 (generic name: N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide], molecular weight: 637)
IRGANOX 259 (generic name: hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], molecular weight: 639)

The blending ratio of each component is not particularly limited, but usually 99.0 to 99.5 parts by mass of an acrylic resin that substantially does not contain a carboxyl group in the adhesive composition, and 0.05 to 9% of the silane coupling agent. 0.15 parts by mass, 0.06 to 0.20 parts by mass of a benzotriazole-based compound, and 0.06 to 0.20 parts by mass of a hindered phenol-based antioxidant are contained.
The thickness of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition is usually about 5 to 40 μm.

Hereinafter, the present invention will be described more specifically with reference to examples. These descriptions do not limit the present invention.
(1) Preparation of sheet member A including conductive pattern layer A so-called drawing primer intaglio printing using a PET (polyethylene terephthalate) film, a conductive layer composition having the following composition, and a primer layer composition having the following composition as a transparent substrate. A conductive pattern layer is printed by a method, and a 2 μm thick copper layer is formed on the surface of the conductive pattern layer by an electrolytic plating method using a copper sulfate bath. Created.
The size of the obtained conductive pattern layer is a square lattice in which the arrangement period of the vertical and horizontal conductive lines is 275 μm in plan view, and the main cut surface shape of the conductive lines has a height (thickness) of 18 μm, The line width was 25 μm at the widest portion on the transparent substrate side and 17 μm at the narrowest portion at the top.

<Composition for conductive layer>
The composition for conductive layers has the following composition.
-Silver powder with an average particle size of about 2 μm 93 parts by mass-Thermoplastic polyester urethane resin 7 parts by mass-25 parts by mass butyl carbitol acetate (solvent) The composition for conductive layers was prepared by kneading.

<Composition for primer layer>
The primer layer composition has the following composition.
-Epoxy acrylate prepolymer 35 parts by mass-Urethane acrylate prepolymer 12 parts by mass-Phenoxyethyl acrylate 44 parts by mass-Ethylene oxide modified isocyanuric acid triacrylate 9 parts by mass-Irgacure 184 (substance name: 1-hydroxy-cyclohexyl- as a photoinitiator Phenyl-ketone, manufacturer: Ciba Specialty Chemicals) 3 parts by weight The viscosity of the composition is about 1300 cps (25 ° C., B-type viscometer), and the primer layer after application shows fluidity when touched, but PET It did not run off from the film.

(2) Preparation of sheet member B including contrast improving layer After applying a composition for a light transmission part having the following composition on one surface of a PET film, embossing and photocuring to form a light transmission part, Fill the wedge-shaped groove, which is the boundary between the units of the light transmitting part, with the composition for the light absorbing part, and light cure to form the light absorbing part, thereby creating a sheet member B including a contrast improving layer did.
<Composition for light transmission part>
(Prepolymer) Epoxy acrylate prepolymer: 40 parts by mass (prepolymer) Urethane acrylate prepolymer: 10 parts by mass (monofunctional monomer) Phenoxyethyl acrylate: 45 parts by mass (trifunctional monomer) Trimethylolpropane triacrylate: 10 parts by mass (Release mold) Silicone resin mold release agent: 1 part by mass (photopolymerization initiator) 1-hydroxy-cyclohexyl-phenyl-ketone (trade name Irgacure 184 manufactured by Ciba Specialty Chemicals): 3 parts by mass <Composition for light absorption part>
(Binder) Resin composition of the light transmission part: 90 parts by mass (light absorption particles) Particles having an average particle diameter of 2.0 μm made of urethane-crosslinked resin containing carbon black: 10 parts by mass

  The size and shape of the obtained contrast enhancement layer are as follows: the main cut surface of the light absorption part is trapezoidal, the height is 85 μm, the length of the lower base, which is the larger base, is 10 μm, and the base of the smaller one. The length of the upper base is 4 μm. The lower base is the surface side of the light transmission part, and the upper base is the PET film side. The light absorbing portion was arranged with wedge-shaped stripes with their extending directions parallel to each other, and the arrangement period in the arrangement direction (direction perpendicular to the extending direction) was 80 μm.

(3) Preparation of adhesive composition Each adhesive composition having the composition shown in Table 1 (1 / 3-3 / 3) below was prepared. In addition, content (value displayed in the mass part unit) in a table | surface is the real compounding quantity converted into solid content.
Adhesive composition 1 was prepared by the following procedure. Curing agent (trade name: TD75, solid content: 75%, manufactured by Soken Chemical Co., Ltd.) with respect to 60 parts by mass of acrylic resin (trade name: SK1811L, solid content: 23%, manufactured by Soken Chemical Co., Ltd.) 0.24 parts by mass, 0.054 parts by mass of a silane coupling agent (trade name: A50, solid content: 5%, manufactured by Seiden Chemical Co., Ltd.), benzotriazole-based compound (trade name: TH-BTA, solid) Min. 100%, manufactured by Johoku Chemical Co., Ltd.) 0.07 parts by mass, hindered phenol antioxidant (trade name: IRGANOX MD1024, solid content 100%, manufactured by BASF Japan Ltd.) 0.07 parts by mass A pressure-sensitive adhesive composition 1 (the solid content is about 15%) was prepared by mixing partly, diluting with 32 parts by mass of toluene, and sufficiently dispersing.
Other pressure-sensitive adhesive compositions shown in Table 1 (about 15% solid content) were also prepared in the same procedure as the pressure-sensitive adhesive composition 1.

(4) Production of pressure-sensitive adhesive sheet 25 g / m ^{2 of} the pressure-sensitive adhesive obtained as described above on a release film (PET separator, trade name: Therapy BX, film thickness: 38 μm, manufactured by Toray Film Processing Co., Ltd.) After coating to dryness (when dry) and drying sufficiently, a release film (PET separator, trade name: Therapy MD, film thickness: 38 μm, manufactured by Toray Film Processing Co., Ltd.) is laminated. A pressure-sensitive adhesive sheet was obtained.

(5) Examples and comparative examples (creation of composite films)
Table 2 shows the laminated structure of the composite films prepared in Examples and Comparative Examples.
The sheet member A including the conductive pattern layer and the sheet member B including the contrast improving layer are arranged with the former conductive pattern layer and the latter light absorbing portion facing each other, with the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet interposed therebetween. A composite film was prepared by laminating. The thickness of the pressure-sensitive adhesive layer after lamination was 25 μm.
Moreover, it replaced with the said sheet | seat member B containing a contrast improvement layer, and the composite film using a simple PET film was also created.
Therefore, the composite film has one of the following laminated structures.
<Laminated structure 1> Sheet member A including conductive pattern layer / adhesive layer / sheet member B including contrast improving layer
<Laminated structure 2> Sheet member A containing conductive pattern layer / adhesive layer / PET film

(6) Evaluation method The prepared composite film was put into an oven at 80 ° C. and taken out after 500 hours, and the composite film was put into a constant humidity chamber with a relative humidity (RH) of 95% at 60 ° C. and taken out after 500 hours. The two types of durability test conditions were evaluated.
Each evaluation item was evaluated by the following method. The results are shown in Table 2.
(6-1) Adhesiveness After 24 hours for each composite film taken out from the oven and the thermo-hygrostat, whether the adhesive layer of the composite film is not lifted from the conductive pattern layer (partially peeled and voids) It was visually confirmed and evaluated according to the following criteria.
<Evaluation criteria for adhesion test>
Good adhesion (O): No floating occurred under the two types of durability test conditions.
Adhesive failure (x): Floating occurred in at least one of the two types of durability test conditions.

(6-2) Discoloration The transmittance of the adhesive layer of the composite film is measured before the composite film is put into the oven and the constant temperature and humidity chamber, and after 24 hours from the removal from the oven and the constant temperature and humidity chamber. At each time point, measurement was performed using a spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation, using C light source), and a chromaticity value at each time point was calculated. And the difference ((DELTA) x, (DELTA) y) of the chromaticity value before injection | throwing-in before and after injection | throwing-in of the said oven and a constant temperature and humidity chamber was computed, and it evaluated according to the following reference | standard.
No change in color of the pressure-sensitive adhesive (◯): Δx and Δy were both less than 0.005 in both of the two types of durability test conditions.
Adhesive color change (x): Δx and Δy were both 0.005 or more in at least one of the two types of durability test conditions.

(7) Comprehensive evaluation In Examples 1 and 2, which are the products of the present invention, the adhesive layer had good adhesion and no discoloration occurred.
Since the comparative example 1 used the acrylic adhesive which has a carboxyl group, even if it did not contain a silane coupling agent, adhesiveness was favorable. However, discoloration occurred because an acrylic pressure-sensitive adhesive having a carboxyl group was used.
Since Comparative Example 2 did not contain a silane coupling agent in contrast to Example 1, the adhesion was poor. On the other hand, since an acrylic pressure-sensitive adhesive containing substantially no carboxyl group was used, no discoloration occurred.
Since the comparative example 3 did not contain a hindered phenolic antioxidant in comparison with the example 1, discoloration occurred. On the other hand, despite the use of an acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group, the adhesion was good because a silane coupling agent was combined.
Since the comparative example 4 did not contain a hindered phenolic antioxidant in comparison with the example 2, discoloration occurred. On the other hand, despite the use of an acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group, the adhesion was good because a silane coupling agent was combined.
Since Comparative Example 5 did not contain a benzotriazole compound in comparison with Examples 1 and 2, discoloration occurred. On the other hand, despite the use of an acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group, the adhesion was good because a silane coupling agent was combined.
Comparative Example 6 is an experiment in which the amount of hindered phenolic antioxidant was increased in comparison with Comparative Example 5. From this experiment, it was confirmed that when no benzotriazole-based compound was contained, discoloration occurred even when the amount of hindered phenol-based antioxidant was increased.
Comparative Example 7 is an experiment in which the amount of benzotriazole compound was increased in comparison with Comparative Example 3. From this experiment, it was confirmed that discoloration occurred even when the amount of the benzotriazole-based compound was increased in the case where the hindered phenol-based antioxidant was not contained.
Comparative Example 8 is an experiment in which the amount of benzotriazole-based compound was increased in comparison with Comparative Example 4. From this experiment, it was confirmed that discoloration occurred even when the amount of the benzotriazole-based compound was increased in the case where the hindered phenol-based antioxidant was not contained.
Since Comparative Example 9 did not contain a silane coupling agent in contrast to Example 2, the adhesion was poor. On the other hand, since an acrylic pressure-sensitive adhesive containing substantially no carboxyl group was used, no discoloration occurred.
Comparative Example 10 is an experimental example using an acrylic adhesive having a carboxyl group in the same amount as the acrylic adhesive having substantially no carboxyl group of Example 1 in contrast to Example 1. From this experiment, it was confirmed that when an acrylic pressure-sensitive adhesive having a carboxyl group was used, the adhesion was good without containing a silane coupling agent, but discoloration occurred.
Comparative Examples 11 to 14 are experimental examples in which a simple PET film is laminated instead of the contrast improving layer in comparison with Comparative Examples 1, 3, 4, and 7. From this experiment, it was confirmed that no discoloration of the pressure-sensitive adhesive layer occurred in the first place when the layer to be bonded via the pressure-sensitive adhesive layer was not formed using the photocurable resin composition.
The results of each experimental example are summarized as follows.
When an acrylic pressure-sensitive adhesive having a carboxyl group is used, adhesion is good, but discoloration occurs (Comparative Examples 1 and 10).
When the layer bonded to the conductive pattern layer through the pressure-sensitive adhesive layer is not formed using the photocurable resin composition, the problem that the pressure-sensitive adhesive layer is discolored does not occur in the first place. (Comparative Examples 11-14)
An acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group has good adhesion when used in combination with a silane coupling agent. (Comparison between Example 1 and Comparative Example 2, Comparison between Example 2 and Comparative Example 9)
Discoloration cannot be prevented only by using an acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group in place of the acrylic pressure-sensitive adhesive having a carboxyl group. An acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group can prevent discoloration when used in combination with both a benzotriazole-based compound and a hindered phenol-based antioxidant. (Comparative Examples 3-5)
When only an acrylic pressure-sensitive adhesive that does not substantially contain a carboxyl group and a benzotriazole compound are used in combination, and no hindered phenol antioxidant is used, discoloration cannot be prevented even if the amount of the benzotriazole compound is increased. (Comparative Examples 7 and 8)
When only acrylic adhesives and hindered phenolic antioxidants that do not substantially contain carboxyl groups are used in combination, and benzotriazole compounds are not used, discoloration will occur even if the amount of hindered phenolic antioxidants is increased. It cannot be prevented. (Comparative Example 6)

101: Front filter for image display device 102: PDP panel 1: Transparent substrate 2: Conductive pattern layer 2a containing metal: Conductive line 2b: Opening portion 3: Adhesive layer 4: Contrast improving layer 5: Primer layer 6: Light transmission part 7: Light absorption part 8: Ground pattern 10: Gravure plate roll 11: Container 12: Pickup roll 13: Doctor blade 14: First nip roll 15: Ionizing radiation irradiation zone 16: Second nip roll 17: Conductive layer Composition 18: transparent substrate

Claims (2)

A front filter for an image display device including a laminated structure in which a functional layer obtained by curing a photocurable resin composition on a conductive pattern layer containing a metal is bonded via an adhesive layer,
An image characterized in that the pressure-sensitive adhesive layer is formed by using a pressure-sensitive adhesive composition containing an acrylic resin substantially free of carboxyl groups, a silane coupling agent, a benzotriazole-based compound, and a hindered phenol-based antioxidant. Front filter for display devices.   The image display apparatus which has arrange | positioned the front filter for image display apparatuses of Claim 1 in the viewer side of the image display apparatus main body.

Images