JP2011039823A - Protection sheet for touch panel and electroconductive laminate for the touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection sheet for touch panel that improves cushioning properties without reducing surface hardness or causing a curl, and to provide an electroconductive laminate for the touch panel using the same. <P>SOLUTION: The protection sheet for touch panel includes: a front-face film 10 having a first base material 11 and a first hardcoat layer 12 formed on the front face of the first base material 11; a rear-face film 20 having a second base material 21, a second hardcoat layer 22 formed on the front face of the second base material 21, and a third hardcoat layer 23 formed on the rear face of the second base material; and a first adhesive layer 31 formed between the rear face of the front-face film 10 and the front face of the rear face film 20, to bond the films. The thickness of the first base material 11 is larger than the thickness of the second base material 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a protective sheet for a touch panel and a conductive laminate for a touch panel. More specifically, the present invention relates to a protective sheet suitable for protecting the surface of a resistive film type touch panel, and a conductive laminate for a touch panel including the protective sheet.

A touch panel is an electronic component combining a display device such as a liquid crystal panel and a position input device, and is widely used in mobile phones, portable game machines, and the like.
In the touch panel, when pressure is applied with a hand or an input pen based on the screen display, the position information of the part to which pressure is applied can be sensed, and an appropriate operation desired by the operator can be performed based on the position information. .

There are methods based on various principles for detecting the position of a portion to which pressure is applied. Among them, a resistance film type detection method is widely used.
The resistance film type detection method is a method of detecting a position by a voltage between two opposing transparent conductive films. When a voltage is applied to one of the two sheets, a voltage corresponding to the operated position is generated in the other transparent conductive film. By detecting this voltage, the place operated as an analog quantity can be detected.

In a touch panel using a resistance film type detection method, a conductive sheet in which a transparent conductive film is provided on a film base is used. Patent Documents 1 and 2 disclose a conductive laminate in which a protective sheet is attached to the surface of the conductive sheet opposite to the transparent conductive film.
In both patent documents, the protective sheet is composed of a hard coat film, and the scratch resistance of the operation surface is improved. Moreover, the damage prevention of a transparent conductive film and the improvement of a position detection characteristic are aimed at by the cushion effect of the adhesive layer for sticking a protective sheet.
In addition, although the protective sheet of patent document 1 is provided with the hard-coat layer only in the surface of the base material (operation surface side), the protective sheet of patent document 2 is both surfaces of a base material in order to prevent curl. Is provided with a hard coat layer.
Examples of commercially available products having a hard coat layer on both sides of the base material include, for example, an antifouling property manufactured by Sumitomo Chemical Co., Ltd., which has an antifouling hard coat layer on the front side surface and an antistatic hard coat layer on the back side. Examples of the coating high-performance sheet Sumirec CW06 (Non-Patent Document 1).

JP-A-2-129808 Japanese Patent Laid-Open No. 8-148036

Sumitomo Chemical Co., Ltd. Catalog “Anti-fouling coating high-performance sheet”, April 2009

In recent years, there has been a demand for further prevention of damage to the transparent conductive film and improvement of position detection characteristics from the viewpoints of diversification of touch panel position detection methods, requirements for pen input and durability in outdoor use, and the like. Therefore, it is conceivable to attach a plurality of protective sheets to the conductive sheet for the purpose of obtaining a further cushion effect.
However, increasing the number of laminated protective sheets naturally increases the film thickness of the entire display surface, which is contrary to the demand for thinner and lighter devices. In addition, since the cost of the hard coat film is high, there is a limit to the increase in the number of protective sheets laminated from the cost aspect.

Accordingly, the present inventors can divide the base material of the protective sheet described in Patent Document 2 in half in the thickness direction and insert an adhesive layer between them, thereby sticking a single protective sheet, which is more than conventional. I thought that the cushioning effect could be obtained.
However, as a result of examination, it was found that when the substrate was divided in half, the base material became thin, which caused curling. It has also been found that if the base material supporting the hard coat layer on the operation surface side is thin, the surface hardness of the operation surface is reduced.
This invention is made | formed in view of the said situation, Comprising: The protective sheet for touchscreens which can improve cushioning properties without causing curling and a fall of surface hardness, and the electroconductivity for touchscreens using this protective sheet It is an object to provide a conductive laminate.

  In order to achieve the above object, the present invention employs the following configuration.

[1] A first base material and a surface film having a first hard coat layer provided on the front surface of the first base material, a second base material, and provided on the front surface of the second base material A second hard coat layer and a back film having a third hard coat layer provided on the back side surface of the second base material, provided between the back side surface of the front film and the front side surface of the back film; A protective sheet for a touch panel, comprising a first pressure-sensitive adhesive layer for attaching both films, wherein the thickness of the first substrate is larger than the thickness of the second substrate.
[2] The protective sheet for a touch panel according to [1], wherein the thickness of the first hard coat layer is larger than the thickness of the third hard coat layer.
[3] The protective sheet for a touch panel according to [1] or [2], wherein the thickness of the second hard coat layer and the thickness of the third hard coat layer are substantially equal.
[4] The protective sheet for a touch panel according to any one of [1] to [3], wherein a printed layer is provided on the back surface of the third hard coat layer.
[5] The protective sheet for a touch panel according to any one of [1] to [4], a conductive sheet having a third base material and a transparent conductive film provided on a back surface of the third base material, A conductive laminate for a touch panel, comprising a second pressure-sensitive adhesive layer that is provided between a back surface of the protective sheet for a touch panel and a front surface of the conductive sheet, and affixes both the sheets.
In the present invention, the front side means the surface side operated by the operator during use, and the back side means the side opposite to the surface operated by the operator during use (inside the touch panel device).

According to the protective sheet for a touch panel of the present invention, excellent cushioning properties can be imparted to the conductive laminate for a touch panel without causing a problem of curling or surface hardness reduction.
According to the conductive laminate for a touch panel of the present invention, it is possible to highly prevent damage to the transparent conductive film of the touch panel and improve the position detection characteristics.

It is sectional drawing of the protective sheet for touchscreens which concerns on one Embodiment of this invention. It is sectional drawing of the conductive laminated body for touchscreens which concerns on one Embodiment of this invention.

[Protective sheet]
As shown in FIG. 1, the protective sheet 1 for a touch panel according to an embodiment of the present invention is configured such that a front film 10 and a back film 20 are bonded via an adhesive layer 31.
The surface film 10 has a first base 11 and a first hard coat layer 12 provided on the front side surface of the first base 10.
The back film 20 includes a second base material 21, a second hard coat layer 22 provided on the front side surface of the second base material 21, and a third hard coat provided on the back side surface of the second base material 21. It has a layer 23.
Print layers 41 and 42 are formed on the back side of the third hard coat layer 23 of the back film 20.

As the first substrate 11 and the second substrate 21, a polyethylene terephthalate film, a polyethylene naphthalate film, a polypropylene terephthalate film, a polybutylene terephthalate film, a polypropylene naphthalate film, a polyethylene film, a polypropylene film, a cellophane, a diacetyl cellulose film, a tri Acetyl cellulose film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether Ketone film, polyethersulfone film, polyester Ether imide film, polyimide film, fluorine resin film, a polyamide film, and acrylic resin film.
In particular, it is preferable to use a polyethylene terephthalate film from the viewpoints of transparency, weather resistance, solvent resistance, rigidity, and cost.

Each of the first base material 11 and the second base material 21 may contain various additives. Examples of the additive include antioxidants, heat stabilizers, ultraviolet absorbers, organic particles, inorganic particles, pigments, dyes, antistatic agents, nucleating agents, and coupling agents.
The back surface of the first substrate 11 may be subjected to a surface treatment in order to improve the adhesion with the adhesive layer 31. Examples of the surface treatment include surface roughening treatment such as sandblast treatment and solvent treatment, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like.

The first hard coat layer 12, the second hard coat layer 22, and the third hard coat layer 23 (hereinafter collectively referred to simply as “hard coat layer”) contain a hard component for imparting surface hardness. To do.
A hard component has an acrylic polymer as a main component. The hard component may contain reactive inorganic oxide particles and / or reactive organic particles. In particular, it is preferable that the first hard coat layer 12 contains reactive inorganic oxide particles and / or reactive organic particles because antifouling properties, fingerprint adhesion prevention properties, antistatic properties and the like can be imparted.

The acrylic polymer is a monomer or oligomer polymer having a polymerizable unsaturated group.
The monomer or oligomer of the organic compound having a polymerizable unsaturated group is preferably a polyfunctional (meth) acrylate, such as dipropylene glycol di (meth) acrylate or 1,6-hexanediol di (meth) acrylate. , Tripropylene glycol di (meth) acrylate, polyethylene glycol (mass average molecular weight 600) di (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, modified bisphenol A di (meth) acrylate, tricyclodecane dimethanol Difunctional (meth) acrylates such as di (meth) acrylate, polyethylene glycol (mass average molecular weight 400) di (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylol pro Tri (meth) acrylate, trimethylolpropane ethoxytri (meth) acrylate, polyether tri (meth) acrylate, trifunctional (meth) acrylate such as glycerol propoxytri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol 4 such as ethoxytetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. (Meth) acrylate more than functional is mentioned. These polyfunctional acrylates may be used individually by 1 type, and can also be used in combination of 2 or more type.
In order to make the pencil hardness of the obtained hard coat layer 3H or higher, it is more preferable to select a tetrafunctional or higher (meth) acrylate.
The monomer or oligomer of the organic compound having a polymerizable unsaturated group may be thermosetting or active energy ray curable.

The hard coat layer may contain a flexible component. If the flexible component is contained, the occurrence of cracks when punched with a high gel fraction can be further prevented.
Examples of the flexible component include (meth) acrylates having a polymerizable unsaturated group having one or more polymerizable unsaturated groups in the molecule. Examples of the (meth) acrylates include tricyclodecanemethylol di (meth) acrylate, ethylene oxide-modified di (meth) acrylate of bisphenol F, ethylene oxide-modified di (meth) acrylate of bisphenol A, ethylene oxide of isocyanuric acid Modified di (meth) acrylate, polypropylene glycol di (meth) acrylate, bifunctional (meth) acrylate such as polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylpropane propylene oxide modified tri (meth) Acrylate, trifunctional (meth) acrylate such as trimethylpropane ethylene oxide modified tri (meth) acrylate, urethane (meth) acrylate, polyester ( Data) acrylate, polyether (meth) acrylate. In particular, it is more preferable to select trifunctional (meth) acrylate and urethane (meth) acrylate.
These (meth) acrylates can be used singly or in combination of two or more.

The reactive inorganic oxide particles are inorganic oxide particles treated with a coupling agent, and the reactive organic particles are organic particles treated with a coupling agent. By treating the inorganic oxide particles or the organic particles with a coupling agent, the bonding strength with the acrylic polymer can be increased. As a result, surface hardness and scratch resistance can be improved, and dispersibility of inorganic oxide particles and organic particles can be improved.
Here, the inorganic oxide particles preferably have high hardness. For example, silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, aluminum oxide particles and the like can be used.
Examples of organic particles that can be used include resin particles such as acrylic resin, polystyrene, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, cellulose acetate, polycarbonate, and polyamide.
Examples of the coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxy. Examples thereof include silane, γ-aminopropyltriethoxysilane, and γ-aminopropyltriethoxyaluminum. These may be used individually by 1 type and may use 2 or more types together.
The amount of the coupling agent to be treated is preferably 0.1 to 20 parts by mass and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the inorganic oxide particles or the organic particles.

As the adhesive constituting the adhesive layer 31, for example, a natural rubber adhesive, a synthetic rubber adhesive, an acrylic adhesive, a urethane adhesive, a silicone adhesive, or the like is used. Moreover, any of solvent system, emulsion system, and water system may be sufficient. Among these, acrylic solvent-based pressure-sensitive adhesives are particularly preferable from the viewpoints of transparency, weather resistance, durability, cost and the like when used for optical system applications.
Other auxiliary agents may be added to the adhesive as necessary. Other auxiliary agents include thickeners, pH adjusters, tackifiers, binders, crosslinking agents, adhesive fine particles, antifoaming agents, antiseptic / antifungal agents, pigments, inorganic fillers, stabilizers, wetting agents, wetting agents. Etc.

The printing layers 41 and 42 include colorants (pigments, dyes) and binders (polyvinyl resins, polyamide resins, polyacrylic resins, polyurethane resins, polyvinyl acetal resins, polyester urethane resins, cellulose ester resins, alkyds. Resin) and a colored ink containing the resin. In the case of forming a metal color, metal particles such as aluminum, titanium and bronze, and a pearl pigment obtained by coating mica with titanium oxide can be used.
The print layers 41 and 42 are provided, for example, for concealing or decorating internal circuits.

In the present embodiment, the thickness of the first base material 11 is larger than the thickness of the second base material 21. By increasing the thickness of the first base material 11, the surface film 10 can be prevented from curling. The surface film 10 has a hard coat layer only on one side, but curl can be prevented because a certain strength is obtained by ensuring the thickness of the first base material 11 itself.
Further, since the first hard coat layer 12 can be sufficiently supported, it is easy to ensure the hardness of the surface of the first hard coat layer 12.
On the other hand, although the thickness of the 2nd base material 21 is small, the back film 20 has a hard-coat layer on both surfaces. Therefore, the strength of the entire back film 20 can be secured, and the strength of both surfaces is balanced, so that curling can be prevented.
Moreover, since the request | requirement about the hardness of the 3rd hard-coat layer 23 surface is not high, even if the thickness of the 2nd base material 21 which supports the 3rd hard-coat layer 23 is small, there is no problem.

Although the thickness of the 1st base material 11 is based also on the intensity | strength which the material has, it is preferable that it is 25-250 micrometers, and it is more preferable that it is 75-125 micrometers. Although the thickness of the 2nd base material 21 is based also on the intensity | strength which the material has, it is preferable that it is 25-200 micrometers, and it is more preferable that it is 30-100 micrometers.
The ratio of the thickness of the first base material 11 and the second base material 21 is preferably 10: 1 to 1.25: 1 and more preferably 5: 1 to 1.25: 1 when the respective materials are equal. The total thickness of the first base material 11 and the second base material 21 is preferably 60 to 450 μm, and more preferably 100 to 225 μm, although it depends on the strength of each material.
The total thickness of the first base material 11 and the second base material 21 is the one-layer base material when the space between the first hard coat layer 12 and the third hard coat layer 23 is constituted by a single base material. It can be made almost equal to the thickness required for.

In the present embodiment, the thickness of the first hard coat layer 12 is larger than the thickness of the third hard coat layer 23. The thickness of the second hard coat layer 22 and the thickness of the third hard coat layer 23 are substantially the same. Therefore, the thickness of the first hard coat layer 12 is larger than the thickness of the second hard coat layer 22.
The reason why the thickness of the first hard coat layer 12 is increased is that the surface of the first hard coat layer 12 is an operation surface, and thus high surface hardness is required.
On the other hand, although the thickness of the third hard coat layer 23 is small, the requirement for the hardness of the hard coat layer surface is not high, so there is no problem even if the thickness is small. However, if the thickness of the third hard coat layer 23 is extremely small, the back film 20 tends to curl. Moreover, when the front surface film 10 and the back surface film 20 are bonded together, the balance of the strength of both surfaces of the entire touch panel protective sheet 1 is lost, and curling easily occurs.

  It is preferable to make the thickness of the second hard coat layer 22 and the thickness of the third hard coat layer 23 substantially the same because the strength of both surfaces of the back film 20 is balanced and curling of the back film 20 can be prevented. The demand for the hardness of the surface of the second hard coat layer 22 is not higher than that of the third hard coat layer 23. Therefore, the thickness of the second hard coat layer 22 may be smaller than the thickness of the third hard coat layer 23. However, if the thickness of the second hard coat layer 22 is extremely small, the back film 20 tends to curl.

Although the thickness of the 1st hard-coat layer 12 is based also on the intensity | strength which the material has, it is preferable that it is 0.5-20 micrometers, and it is more preferable that it is 3-15 micrometers. If it is 0.5 μm or more, the surface hardness can be sufficiently secured, and if it is 20 μm or less, the workability is improved and the cost increase can be suppressed.
The thickness of the second hard coat layer 22 and the thickness of the third hard coat layer 23 are preferably 0.5 to 10 μm, more preferably 2 to 7 μm, depending on the strength of the material. .
The ratio of the thicknesses of the first hard coat layer 12 and the third hard coat layer 23 is preferably 40: 1 to 1.2: 1 and more preferably 10: 1 to 1.5: 1 when the respective materials are equal. . When the respective materials are equal, the ratio of the thicknesses of the second hard coat layer 22 and the third hard coat layer 23 is preferably 1.5: 1 to 0.6: 1, and 1.2: 1 to 0.8: 1 is more preferable.

The thickness of the pressure-sensitive adhesive layer 31 is preferably 10 to 100 μm, and more preferably 20 to 50 μm. If it is 10 micrometers or more, the surface film 10 and the back film 20 can fully be stuck. The greater the thickness of the pressure-sensitive adhesive layer 31, the greater the effect of improving cushioning properties. Moreover, if the thickness of the adhesive layer 31 is 100 micrometers or less, there is no possibility that a position detection characteristic may be impaired.
The thickness of the printing layers 41 and 42 is preferably 5 to 50 μm, and more preferably 10 to 30 μm.

The protective sheet of the present invention may not have the print layers 41 and 42. Moreover, you may have another layer in the back side of the back film 20. As shown in FIG. Examples of the other layer include a pressure-sensitive adhesive layer and a release sheet that protects the pressure-sensitive adhesive layer.
Moreover, you may have another protective sheet as another layer. Examples of other protective sheets include the protective sheets described in Patent Documents 1 and 2 in addition to the protective sheet of the present invention.

[Protective sheet manufacturing method]
The protective sheet 1 for touch panels can be manufactured as follows, for example.
(1) 1st base material formation process The 1st hard-coat layer 12 is formed in the single side | surface of the 1st base material 10, and the surface film 10 is obtained.
(2) Second Substrate Formation Step A back film 20 is formed by forming a hard coat layer 22 on one surface of the second substrate 21 and a third hard coat layer 23 on the other surface of the second substrate 21. To do.
(3) Adhesion process The surface film 10 and the back film 20 are adhered via the adhesive layer 31.
(4) Printing Step Print layers 41 and 42 are formed on the back side of the back film 20.
(5) Punching process Punching into a desired form.

In the above “(1) first substrate forming step” and “(2) second substrate forming step”, the hard coat layer can be formed as follows.
First, an uncured coating film is formed by applying a hard coat layer-forming coating solution containing a hard component to each substrate.
Examples of the solvent include methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, toluene, n-hexane, n-butyl alcohol, methyl isobutyl ketone, methyl butyl ketone, ethyl butyl ketone, cyclohexanone, ethyl acetate, butyl acetate, propylene glycol monomethyl. Ether acetate, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, N-methyl-2-pyrrolidone and the like are used. These may be used alone or in combination of two or more. In order to reduce coating unevenness, it is preferable to use solvents having different evaporation rates. For example, it is preferable to use a mixture of methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol monomethyl ether.
Moreover, it is preferable that the coating liquid for hard-coat layer formation contains a well-known photoinitiator in order to accelerate hardening. Moreover, when using a thermosetting hard component, it is preferable to contain crosslinking agents, such as an isocyanate compound and an epoxy compound.

  Examples of the coating method for the hard coat layer forming coating liquid include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a micro gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater, and printing. The method using a machine etc. is mentioned.

Next, the uncured coating film is cured. When the uncured coating film contains a thermosetting component, it is cured by heating using a heating furnace or an infrared lamp. When an uncured coating film contains an active energy ray-curable component, it is cured by irradiation with active energy rays.
Examples of the active energy rays include ultraviolet rays and electron beams. Among them, ultraviolet rays are preferable from the viewpoint of versatility. As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, an electrodeless ultraviolet lamp, or the like can be used.
As the electron beam, for example, an electron beam emitted from various electron beam accelerators such as a cockloftwald type, a bandecraft type, a resonant transformation type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type can be used.
Curing by irradiation with active energy rays is preferably performed in the presence of an inert gas such as nitrogen.
The curing process may be performed in two stages, a preliminary curing process and a main curing process.

In the “(3) sticking step”, the front film 10 and the back film 20 can be stuck by any of the following methods.
(A) On the back side of the first substrate 11 in the front film 10, the pressure-sensitive adhesive coating liquid is applied and dried to form the pressure-sensitive adhesive layer 31, and then the back film 20 is adhered.
(B) On the front side of the second hard coat layer 22 in the back film 20, the pressure-sensitive adhesive coating solution is applied and dried to form the pressure-sensitive adhesive layer 31, and then the surface film 10 is adhered.
(C) The adhesive layer 31 is formed on the back side of the first base material 11 in the surface film 10 using a double-sided tape, and then the back film 20 is adhered.
(D) On the front side of the second hard coat layer 22 in the back film 20, the pressure-sensitive adhesive layer 31 is formed using a double-sided tape, and then the surface film 10 is adhered.

The pressure-sensitive adhesive coating liquid in the above (a) and (b) contains a pressure-sensitive adhesive, a solvent, and an auxiliary as necessary. Examples of the solvent include alcohol (for example, methanol, ethanol, propanol, etc.), ketone (for example, acetone, methyl ethyl ketone, etc.), ether (for example, diethyl ether, methyl cellosolve, ethyl cellosolve, etc.) and the like.
Examples of the coater for coating the adhesive layer forming coating solution include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater, and a printing machine. It is done.
Drying is performed by a heat dryer or a vacuum dryer.

The double-sided tapes in the above (c) and (d) are those in which an adhesive layer is provided between a pair of release sheets. A well-known thing can be employ | adopted as a peeling sheet. Examples of the material for the release sheet include paper and film. The release sheet is preferably a single-sided release sheet having a release layer on one side.
Moreover, it is preferable that the peeling force with respect to the adhesive layer of one peeling sheet differs from the peeling force with respect to the adhesive layer of the other peeling sheet. Thereby, it becomes easy to peel only one release sheet first.
When using a double-sided tape, only one release sheet is peeled first to expose the pressure-sensitive adhesive layer, and is attached to one of the surface film 10 or the back film 20. Next, the other release sheet is peeled off and bonded to the other of the back film 20 or the front film 10.

In the above “(4) printing step”, as the formation method (printing method) of the printing layers 41 and 42, an offset printing method, a gravure printing method, a screen printing method, or the like is applied to perform multicolor printing or gradation expression. Is preferably an offset printing method or a gravure printing method.
The “(4) printing step” may be performed before the “(3) sticking step”. That is, you may print on the back surface film 20 before sticking with the surface film 10. FIG. The “(4) printing process” may be performed after the “(5) punching process”.
In the “(5) Punching step”, the punching is performed by inserting a punching blade into the laminated body in which the front film 10 and the back film 20 are bonded together. The punching blade may be one that rotates, or one that reciprocates so as to contact and separate from the laminated body.

[Conductive laminate]
As shown in FIG. 2, the conductive laminate according to one embodiment of the present invention is configured such that the touch panel protective sheet 1 is adhered to the front surface of the conductive sheet 50 via an adhesive layer 32. Has been. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

The conductive sheet 50 includes a third base material 51 and a transparent conductive film 52 provided on the back surface of the third base material 51.
The same thing as the 1st substrate 11 and the 2nd substrate 21 can be used for the 3rd substrate 51. It is preferable that the thickness of the 3rd base material 51 is 25-200 micrometers.
The transparent conductive film 52 is a transparent conductive film. For example, gold, silver, platinum, palladium, copper, aluminum, nickel, chromium, titanium, iron, cobalt, tin, metals made of these alloys, indium oxide, tin oxide, titanium oxide, cadmium oxide, mixtures thereof, etc. And other metal compounds made of copper iodide and the like, and films made of conductive resins. Among these, indium tin oxide (ITO) and conductive resin are preferable.
In order to use the transparent conductive film 52 as an electrode plate for a touch panel, the surface resistance is preferably 10 ³ Ω / □ or less, and more preferably 10 ⁹ Ω / □ or less. Such surface resistance can usually be achieved by setting the thickness to 30 to 600 mm in the case of a metal system and 80 to 5000 mm in the case of a metal oxide system.
The pressure-sensitive adhesive layer 32 can be the same as the pressure-sensitive adhesive layer 31. The preferable thickness of the pressure-sensitive adhesive layer 32 is the same as that of the pressure-sensitive adhesive layer 31.

The conductive sheet 50 may further have another layer on the third substrate 51. Examples of the other layer include a pressure-sensitive adhesive layer and a release sheet that protects the pressure-sensitive adhesive layer.
Moreover, you may have another protective sheet as another layer. Examples of other protective sheets include the protective sheets described in Patent Documents 1 and 2 in addition to the protective sheet of the present invention.

[Method for producing conductive laminate]
The conductive sheet 50 of FIG. 2 is obtained by providing a transparent conductive film 52 on one side of the third base material 51. The transparent conductive film 52 is formed by an appropriate thin film forming method such as a vacuum deposition method, a sputtering method, an ion plating method, a spray pyrolysis method, a chemical plating method, an electroplating method, a coating method, or a combination thereof. It can be performed by attaching a film made of a transparent conductive film-forming material on the film. From the viewpoints of film formation speed, large-area film formability, productivity, and the like, vacuum deposition and sputtering are preferred.
Prior to the formation of the transparent conductive film 52, the surface of the third substrate 51 is subjected to appropriate pretreatment such as corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputter etching treatment, undercoat treatment, etc. It is also possible to improve the adhesion.

The conductive laminate of FIG. 2 can be manufactured by sticking the touch panel protective sheet 1 to the front surface of the conductive sheet 50 via the adhesive layer 32.
The protective sheet 1 can be attached to the conductive sheet 50 by any of the following methods.
(A ′) On the back side of the protective sheet 1, the pressure-sensitive adhesive coating liquid is applied and dried to form the pressure-sensitive adhesive layer 32, and then adhered to the conductive sheet 50.
(B ′) On the front side of the conductive sheet 50, the pressure-sensitive adhesive coating liquid is applied and dried to form the pressure-sensitive adhesive layer 32, and then the protective sheet 1 is adhered.
(C ′) The pressure-sensitive adhesive layer 32 is formed on the back side of the protective sheet 1 using a double-sided tape, and then adhered to the conductive sheet 50.
(D ′) The pressure-sensitive adhesive layer 32 is formed on the front side of the conductive sheet 50 using a double-sided tape, and then the protective sheet 1 is adhered.
The pressure-sensitive adhesive coating liquid in the above (a ′) and (b ′) is the same as the pressure-sensitive adhesive coating liquid in the above (a) and (b).
The double-sided tape in (c ′) and (d ′) and the method of use thereof are the same as the double-sided tape in (c) and (d) and the method of use thereof.

[Touch panel]
Using the conductive laminate of the present invention, a resistive film type touch panel that detects a position by a voltage between two transparent conductive films facing each other can be configured. In the touch panel, the transparent conductive film of the conductive laminate of the present invention is a conductive film disposed on the front side of the two transparent conductive films facing each other.
In the touch panel using the conductive laminate of the present invention, the transparent conductive film is hardly damaged, and the position detection characteristics are excellent.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. In the examples, “%” indicates mass% unless otherwise specified.

[Example 1]
(Creation of film A)
As the first substrate, biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness: 100 μm) was used. A hard coating agent (trade name “Aikatron Z711”, solid content concentration 40%, manufactured by Aika Industry Co., Ltd.) was applied to the front surface of the first base material with a Meyer bar to a dry thickness of 7 μm, and after drying, 300 mJ / A hard coat layer (HC layer) was formed by irradiating cm ² ultraviolet rays to obtain a film A of Example 1.

(Creation of film B)
Biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness 50 μm) was used as the second substrate. A hard coating agent (trade name “Aikatron Z742”, manufactured by Aika Industries Co., Ltd., solid content concentration 25%) is applied to the back surface of the second substrate with a Meyer bar to a dry thickness of 3 μm, and then dried to 300 mJ / cm ^2. The HC layer on the back side was formed by irradiating UV rays.
Next, on the front side surface of the second base material, the same hard coat agent as that on the back side surface is coated and dried so as to have the same thickness, and similarly, the front side HC layer is formed by irradiating ultraviolet rays, and the HC layer is formed on both sides. Film B of Example 1 having

(Create protection sheet)
An acrylic pressure-sensitive adhesive (trade name “Olivein BPS5977”, manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to the non-hard coat surface (back side) of the above film A with a Mayer bar so that the dry thickness was 25 μm, and 100 ° C. After drying for 3 minutes, the protective sheet of Example 1 was obtained by bonding to the front side of the film B.

[Comparative Example 1]
(Creation of film A)
The film A of Comparative Example 1 was prepared in the same manner as in Example 1 except that biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness 75 μm) was used as the first substrate. Obtained.
(Creation of film B)
A film B of Comparative Example 1 was prepared in the same manner as in Example 1 except that biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness 75 μm) was used as the second substrate. Obtained.
(Create protection sheet)
Film A and film B were bonded together in the same manner as in Example 1 to obtain a protective sheet of Comparative Example 1.

[Comparative Example 2]
(Creation of film A)
As a first base material, a hard coat agent (trade name “Aikatron Z711”, manufactured by Aika Industry Co., Ltd.) is used on the front side of biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness 50 μm). The solid content concentration 40%) was applied with a Meyer bar so as to have a dry thickness of 7 μm, dried, and then irradiated with 300 mJ / cm ² of ultraviolet rays to form an HC layer. Similarly, on the back side, the same hard coat agent as the front side is coated and dried so as to have the same thickness, and similarly, the back side HC layer is formed by irradiating with ultraviolet rays, and Comparative Example 2 having HC layers on both sides Film A was obtained.

(Creation of film B)
As the second substrate, biaxially stretched polyethylene terephthalate (PET: trade name “A4300”, manufactured by Toyobo Co., Ltd., thickness 100 μm) was used, and a hard coat agent (trade name “Aikatron Z742”, Aika Kogyo Co., Ltd. (solid content concentration 25%) is coated with a Meyer bar so that the dry thickness is 3 μm, and then an HC layer is formed by irradiating 300 mJ / cm ² of ultraviolet rays, and the HC layer is formed only on the back side. Film B of Example 2 was obtained.

(Create protection sheet)
An acrylic pressure-sensitive adhesive (trade name “Olivein BPS5977”, manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to the back side of the film A with a Meyer bar so that the dry thickness was 25 μm, and dried at 100 ° C. for 3 minutes. Then, the protective sheet of the comparative example 2 was obtained by bonding together with the non-hard coat surface (front side surface) of the film B.

[Evaluation item]
The performances of the protective sheets obtained in Examples and Comparative Examples were evaluated according to the following methods. The results are shown in Table 1.
(Pencil hardness)
The front side surface of film A was measured according to JIS K 5600-5-4 using a pencil scratch coating film hardness tester [Coating Star Industry Co., Ltd.].

(curl)
The protective sheet was cut into a 10 cm square to prepare a test piece, and allowed to stand for 24 hours in an environment of 23 ° C. and 50% RH. After that, place the test piece on a horizontal plate so that the test piece is concave (the concave part is on the upper side), and lift the four corners (distance from the plate surface to each corner) with a ruler. The average value of the four corners was obtained. The results are shown in Table 1.

As shown in Table 1, in Example 1, sufficient pencil hardness was obtained. Further, although the HC layer of film A was only on one side, curling was slight. As a result, according to the present invention, it is possible to confirm that the cushion can be made without increasing the overall thickness and minimizing the number of HC layers while ensuring curl prevention and pencil hardness. It was.
On the other hand, in Comparative Example 1 in which the thicknesses of the first base material and the second base material were equal, a large amount of curl was observed even though the total thickness of both base materials was the same as in Example 1. . This is because the first substrate is thin and the film A having the HC layer only on one side is curled, and as a result, the entire protective sheet is curled.
Further, in Comparative Example 1, the pencil hardness was inferior to that of Example 1 although the thickness of the HC layer on the first base material front side was the same as that of Example 1. Thereby, in order to obtain sufficient pencil hardness, it has confirmed that the thickness of the 1st substrate should be secured.
In Comparative Example 1 in which the first base material was thinner than the second base material, curling did not occur. This is because the film A using the thin first base material has the HC layer on both sides, and the second base material of the film B having the HC layer only on one side has a sufficient thickness.
However, in Comparative Example 2, although the thickness of the HC layer on the front surface side of the first base material was the same as that in Example 1, the pencil hardness was insufficient. Thereby, in order to achieve both prevention of curling and ensuring of pencil hardness, it was confirmed that it was necessary to ensure the thickness of the first substrate.

DESCRIPTION OF SYMBOLS 1 ... Protective sheet, 10 ... Surface film, 11 ... 1st base material,
12 ... 1st hard-coat layer, 20 ... Back film, 21 ... 2nd base material,
22 ... 2nd hard coat layer, 23 ... 3rd hard coat layer, 31 ... Adhesive layer,
41, 42 ... printed layer, 32 ... adhesive layer, 50 ... conductive sheet, 51 ... third substrate,
52. Transparent conductive film

Claims (5)

A surface film having a first base and a first hard coat layer provided on the front side surface of the first base;
A back film having a second substrate, a second hard coat layer provided on the front surface of the second substrate, and a third hard coat layer provided on the back surface of the second substrate;
Provided between the back side surface of the front film and the front side surface of the back film, and includes a first pressure-sensitive adhesive layer for adhering both films,
A protective sheet for a touch panel, wherein the thickness of the first substrate is larger than the thickness of the second substrate.   The protective sheet for a touch panel according to claim 1, wherein the thickness of the first hard coat layer is larger than the thickness of the third hard coat layer.   The protective sheet for a touch panel according to claim 1 or 2, wherein the thickness of the second hard coat layer and the thickness of the third hard coat layer are substantially equal.   The protective sheet for touchscreens in any one of Claims 1-3 which equips the surface of the back side of a 3rd hard-coat layer with a printing layer. A protective sheet for a touch panel according to any one of claims 1 to 4,
A conductive sheet comprising a third base material and a transparent conductive film provided on the back side surface of the third base material;
A conductive laminate for a touch panel, comprising a second pressure-sensitive adhesive layer that is provided between a back surface of the protective sheet for a touch panel and a front surface of the conductive sheet, and affixes both the sheets.

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