WO2019031138A1

WO2019031138A1 - Electroconductive film for transfer

Info

Publication number: WO2019031138A1
Application number: PCT/JP2018/026008
Authority: WO
Inventors: 一裕中島; 菅原　英男; 豪彦安藤; 武田　健太郎
Original assignee: 日東電工株式会社
Priority date: 2017-08-09
Filing date: 2018-07-10
Publication date: 2019-02-14
Also published as: JP2019031040A; CN110997310A; KR20200018689A; TW201931386A

Abstract

Provided is an electroconductive film for transfer which enables the manufacture of an optical laminate that comprises an electroconductive layer and has exceptional bend resistance. This electroconductive film for transfer includes, in the following order, a temporary support body, a liquid crystal layer provided so as to be peelable from the temporary support body, and an electroconductive layer. According to one embodiment, the electroconductive layer is directly laminated on the liquid crystal layer. According to one embodiment, the refractive index of the liquid crystal layer exhibits the relationship nz > nx ≥ ny.

Description

Conductive film for transfer

The present invention relates to a conductive film for transfer.

Conventionally, indium tin complex oxide layer (ITO layer) or the like as a substrate of a transparent resin film (for example, PET film, cycloolefin film) or the like as an electrode of a touch sensor, electromagnetic wave shield or the like employed in mobile devices etc. The transparent conductive film in which the metal oxide layer (conductive layer) of these was formed is used abundantly.

On the other hand, in recent years, with the appearance of wearable devices, foldable devices, etc., it is more flexible and has a high bending resistance transparent conductive film, more specifically, a transparent conductive film in which the conductive layer is difficult to damage even when bent. It has been demanded. As means for improving the bending resistance, it is conceivable to reduce the stress applied to the conductive layer by thinning the substrate. However, from the viewpoint of handling etc., there is a limit to the thin film of the transparent resin film constituting the substrate, and the limit thickness of the transparent resin film is a barrier for improving the bending resistance. Also, as another means of improving the bending resistance, a transparent conductive film provided with a conductive layer composed of a conductive polymer, a metal nanowire or the like instead of the metal oxide layer susceptible to cracking is being studied. Have problems with gender and transparency, and have not been fully introduced.

Patent No. 4893867

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a conductive film for transfer, which is capable of producing an optical laminate having a conductive layer and being excellent in bending resistance. It is.

The conductive film for transfer of the present invention includes a temporary support, a liquid crystal layer provided so as to be peelable from the temporary support, and a conductive layer in this order.
In one embodiment, the conductive layer is directly laminated to the liquid crystal layer.
In one embodiment, the refractive index characteristics of the liquid crystal layer exhibit a relationship of nz> nx ≧ ny.
In one embodiment, the thickness of the liquid crystal layer is 0.1 μm to 10 μm.
In one embodiment, the conductive layer is composed of a metal oxide.
In one embodiment, the conductive layer is patterned.
According to another aspect of the present invention, an optical laminate is provided. The optical laminate includes an optical member, a pressure-sensitive adhesive layer, the conductive layer, and the liquid crystal layer in this order, and the conductive layer is directly laminated on the liquid crystal layer.
In one embodiment, the optical member is a polarizing plate.
In one embodiment, the optical member is a circularly polarizing plate, and the circularly polarizing plate includes a polarizer and a retardation layer functioning as a λ / 4 plate, and the polarizer includes the retardation. It is arranged on the side of the layer opposite to the conductive layer.
In one embodiment, the optical laminate further includes another optical member on the side opposite to the conductive layer of the liquid crystal layer.
In one embodiment, the other optical member is a circularly polarizing plate, and the circularly polarizing plate includes a polarizer and a retardation layer functioning as a λ / 4 plate, and the polarizer includes the polarizer. It is disposed on the side opposite to the liquid crystal layer of the retardation layer.
According to another aspect of the present invention, a touch device is provided. The touch device comprises the optical laminate.
According to another aspect of the present invention, there is provided a method of manufacturing an optical laminate. This manufacturing method includes transferring a laminate including the liquid crystal layer and the conductive layer to an optical member from the conductive film for transfer.

The conductive film for transfer of the present invention has a temporary support, a liquid crystal layer and a conductive layer in this order. If the conductive film for transfer having such a configuration is used, a laminate comprising a liquid crystal layer and a conductive layer can be transferred to another optical member to form an optical laminate. The obtained optical laminate is excellent in bending resistance because it does not have a rigid base (a base necessary for forming a conductive layer). Further, the conductive film for transfer of the present invention is excellent in conductivity and light transmittance since the conductive layer is composed of a metal oxide.

It is a schematic sectional drawing of the electroconductive film for transcription | transfer by one embodiment of this invention. FIG. 1 is a schematic cross-sectional view of an optical laminate according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of an optical laminate according to another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of an optical laminate according to another embodiment of the present invention. It is a graph which shows the result of the bending tolerance test of Example 1 and Comparative Example 1 and Comparative Example 2.

(Definition of terms and symbols)
The definitions of terms and symbols in the present specification are as follows.
(1) Refractive index (nx, ny, nz)
“Nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (ie, the fast axis direction) And “nz” is the refractive index in the thickness direction.
(2) In-plane retardation (Re)
“Re (550)” is an in-plane retardation measured with light having a wavelength of 550 nm at 23 ° C. Re (550) is obtained by the formula: Re = (nx−ny) × d, where d (nm) is the thickness of the layer (film). Note that “Re (450)” is an in-plane retardation measured with light of wavelength 450 nm at 23 ° C.
(3) Retardation in the thickness direction (Rth)
“Rth (550)” is a thickness direction retardation measured with light having a wavelength of 550 nm at 23 ° C. Rth (550) is obtained by the formula: Rth = (nx−nz) × d, where d (nm) is the thickness of the layer (film). “Rth (450)” is the retardation in the thickness direction measured with light of wavelength 450 nm at 23 ° C.
(4) Nz coefficient The Nz coefficient is determined by Nz = Rth / Re.

A. General Configuration of Transfer Conductive Film FIG. 1 is a schematic cross-sectional view of a transfer conductive film according to an embodiment of the present invention. The conductive film for transfer 10 includes a temporary support 11, a liquid crystal layer 12 provided so as to be peelable from the temporary support 11, and a conductive layer 13 in this order. The conductive layer 13 is preferably laminated directly on the liquid crystal layer 12 (that is, without via an adhesive layer or the like).

The conductive film for transfer 10 can be used when applying a conductive layer to the optical laminate. More specifically, the surface on the conductive layer 13 side is attached to another optical member (for example, an image element (for example, liquid crystal panel, organic EL panel), an optical film (for example, retardation film), a polarizing plate, etc.) Thereafter, the temporary support 11 is peeled off, and the laminate A including the liquid crystal layer 12 and the conductive layer 13 is transferred, whereby the conductive layer can be applied to the optical laminate. Conventionally, the conductive layer is applied to the optical laminate in a state of being formed on the substrate, and the optical laminate includes the substrate, but if the conductive film for transfer of the present invention is used, the conductive layer is formed. It is possible to form an optical laminate which does not contain a substrate necessary for the preparation. Usually, the base material is rigid since it functions as a support, but an optical laminate not including such a base material is excellent in flexibility. In addition, in the optical laminate that does not include the base material, when bent, the load on the conductive layer is small, and the conductive layer is unlikely to be damaged.

Furthermore, when the conductive film for transfer of the present invention is used, a rigid substrate is excluded even in an optical laminate including an optical member that is easily damaged during processing (for example, heat treatment) for forming a conductive layer. be able to. For example, when processing such as sputtering is directly performed on a film including a polarizing plate, the polarizing plate is damaged, but when the conductive film for transfer of the present invention is used, the polarizing plate is not damaged. An optical laminate can be formed.

A-1. Conductive Layer In one embodiment, the conductive layer can function as an electrode of a touch device.

Preferably, the conductive layer is composed of a metal oxide. Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin complex oxide, tin-antimony complex oxide, zinc-aluminum complex oxide, indium-zinc complex oxide and the like. Among these, indium-tin complex oxide (ITO) is preferable. Also, the conductive layer may be a layer containing a conductive polymer, a conductive filler, a metal nanowire and / or a metal mesh.

The conductive layer preferably has optical transparency. The total light transmittance of the conductive layer is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. By forming the conductive layer from the metal oxide, a conductive layer with high light transmittance can be formed.

The surface resistance value of the conductive layer is preferably 0.1 Ω / □ to 1000 Ω / □, more preferably 0.5 Ω / □ to 500 Ω / □, and particularly preferably 1 Ω / □ to 250 Ω / □. .

In one embodiment, the conductive layer is formed directly on the liquid crystal layer. As a specific example of the present embodiment, a metal oxide layer is formed on the liquid crystal layer by any appropriate film forming method (for example, a vacuum evaporation method, a sputtering method, a CVD method, an ion plating method, a spray method, etc.) Are formed to obtain a conductive layer. The metal oxide layer may be used as it is as a conductive layer, or may be further heated to crystallize the metal oxide. The heating temperature is, for example, 120 ° C. to 200 ° C.

The thickness of the conductive layer is preferably 50 nm or less, more preferably 40 nm or less. If it is such a range, the conductive layer which is excellent in light transmittance can be obtained. The lower limit of the thickness of the conductive layer is preferably 1 nm, more preferably 5 nm.

The conductive layer may be patterned. As a method of patterning, any appropriate method may be adopted depending on the form of the conductive layer. For example, it may be patterned by an etching method, a laser method or the like. The shape of the pattern of the conductive layer may be any suitable shape depending on the application. For example, the patterns described in JP-A-2011-511357, JP-A-2010-164938, JP-A-2008-310550, JP-A-2003-511799 and JP-A-2010-541109 can be mentioned.

A-2. Liquid Crystal Layer The liquid crystal layer comprises any suitable liquid crystal compound. In the conductive film for transfer of the present invention, the conductive layer is formed on the liquid crystal layer, and the liquid crystal layer is disposed between the conductive layer and the temporary support. The laminate A configured can be transferred to another optical member. It is one of the achievements of the present invention that both a liquid crystal layer and a conductive layer having a predetermined function can be introduced into an optical laminate excluding rigid substrates.

In one embodiment, the liquid crystal layer exhibits a refractive index characteristic of nz> nx ≧ ny. By providing such a liquid crystal layer, the laminate A can be made into a laminate having an optical function.

The thickness direction retardation Rth (550) of the liquid crystal layer is preferably −260 nm to −10 nm, more preferably −230 nm to −15 nm, and still more preferably −215 nm to −20 nm.

In one embodiment, the liquid crystal layer has a refractive index of nx = ny. Here, “nx = ny” includes not only when nx and ny are exactly equal but also when nx and ny are substantially equal. Specifically, it means that Re (550) is less than 10 nm. In another embodiment, the liquid crystal layer has a refractive index of nx> ny. In this case, the in-plane retardation Re (550) of the liquid crystal layer is preferably 10 nm to 150 nm, more preferably 10 nm to 80 nm.

The liquid crystal layer is a liquid crystal layer fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) which can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of the liquid crystal compound and the method of forming the liquid crystal layer include the liquid crystal compound and the forming method described in [0020] to [0042] of JP-A-2002-333642.

The thickness of the liquid crystal layer is preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 5 μm, and still more preferably 0.2 μm to 3 μm. If it is such a range, a desired optical laminated body can be obtained, and the electroconductive film for transfer which is excellent in the peelability of the laminated body A can be obtained.

The total light transmittance of the liquid crystal layer is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more.

A-3. Temporary Support As the resin constituting the temporary support, any appropriate resin can be used as long as the effects of the present invention can be obtained. Examples of the resin constituting the temporary support include cycloolefin resins, polyimide resins, polyvinylidene chloride resins, polyvinyl chloride resins, polyethylene terephthalate resins, polyethylene naphthalate resins, and the like.

The thickness of the temporary support is preferably 8 μm to 500 μm, more preferably 50 μm to 250 μm.

The tackiness of the temporary support to the liquid crystal layer at 23 ° C. is preferably 0.01 N / 25 mm to 1 N / 25 mm, more preferably 0.01 N / 25 mm to 0.7 N / 25 mm. If it is such a range, the electroconductive film for transfer which can transfer the laminated body A easily can be obtained. The adhesive strength is measured by a method according to JIS Z 0237: 2000, and the adhesive strength measured by peeling the temporary support at a tensile speed of 300 mm / min and a peeling angle of 180 ° from the manufactured conductive film for transfer. Say

If necessary, various surface treatments may be performed on the temporary support. As the surface treatment, any appropriate method may be adopted depending on the purpose. In one embodiment, a release layer may be provided on the surface of the temporary support on the liquid crystal layer side in order to facilitate peeling from the liquid crystal layer. The release layer may be a layer composed of any appropriate material as long as the above-mentioned adhesive force can be exhibited, and is formed by, for example, a known release treatment (eg, application of a silicone-based release agent). Layer. In addition, an alignment layer may be provided to enhance the alignment of the liquid crystal layer.

B. Optical Laminate The optical laminate of the present invention includes the laminate A (a laminate including a liquid crystal layer and a conductive layer) transferred from the conductive film for transfer. In one embodiment, a touch device comprising the optical stack is provided. In the touch device, the conductive layer functions as an electrode. The touch device is excellent in flexibility and is also useful in that it is difficult for the conductive layer to be damaged even when it is bent.

FIG. 2 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 100 includes an optical member 20, a conductive layer 13, and a liquid crystal layer 12 in this order. In one embodiment, the optical member 20 and the conductive layer 13 are laminated via the adhesive layer 30, and the adhesive layer 30 is in contact with the optical member 20 and the conductive layer 13.

In the optical laminate 100, a laminate A composed of the conductive layer 13 and the liquid crystal layer 12 is a laminate transferred from the conductive film for transfer. The conductive layer 13 is laminated directly on the liquid crystal layer 12 (that is, without interposing an adhesive layer or the like).

FIG. 3 is a schematic cross-sectional view of an optical laminate according to another embodiment of the present invention. The optical laminate 200 includes an optical member 20, a conductive layer 13, a liquid crystal layer 12, and another optical member 40 in this order. In one embodiment, the optical member 20 and the conductive layer 13 are laminated via the adhesive layer 30, and the adhesive layer 30 is in contact with the optical member 20 and the conductive layer 13. In one embodiment, the liquid crystal layer 12 and another optical member 40 are laminated via the adhesive layer 30, and the adhesive layer 30 is in contact with the liquid crystal layer 12 and another optical member 40.

Examples of the optical member 20 and another optical member 40 include an image element (for example, a liquid crystal panel, an organic EL panel), an optical film (for example, a retardation film), a polarizing plate, a circularly polarizing plate, and the like.

In one embodiment, a polarizing plate or a circularly polarizing plate is used as the optical member 20. According to another embodiment, a polarizing plate or a circularly polarizing plate is used as another optical member 40. When applied to an image display device (for example, a touch device), the optical laminate may be disposed such that the conductive layer is on the viewing side of the polarizing plate or the circularly polarizing plate, and the conductive layer is the polarizing plate or the circular plate. You may be arrange | positioned so that it may become inner side (opposite to a visual recognition side) rather than a polarizing plate.

B-1. Polarizer In one embodiment, an optical laminate in which a polarizer is used as an optical member or another optical member, that is, an optical laminate comprising a polarizer, a conductive layer, and a liquid crystal layer in this order, or There is provided an optical laminate comprising a conductive layer, a liquid crystal layer, and a polarizing plate in this order. Conventionally, when a conductive layer is directly formed on a film including a polarizing plate by a conductive layer applying process such as sputtering, problems such as the polarizing plate being damaged during the conductive layer applying process may occur. If a conductive film is used, an optical layered product can be formed without damaging the polarizing plate. The example of the polarizing plate used for the said optical laminated body is demonstrated below.

The polarizing plate comprises a polarizer. The polarizing plate preferably further comprises a protective film on one side or both sides of the polarizer.

The thickness in particular of the said polarizer is not restrict | limited, According to the objective, appropriate thickness may be employ | adopted. The thickness is typically about 1 μm to 80 μm. In one embodiment, a thin polarizer is used, and the thickness of the polarizer is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, particularly preferably 6 μm or less It is. By using such a thin polarizer, a thin optical laminate can be obtained.

The above-mentioned polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 40.0% or more, more preferably 41.0% or more, still more preferably 42.0% or more, and particularly preferably 43.0% or more. The polarization degree of the polarizer is preferably 99.8% or more, more preferably 99.9% or more, and still more preferably 99.95% or more.

Preferably, the polarizer is an iodine-based polarizer. In more detail, the said polarizer may be comprised from the polyvinyl alcohol-type resin (It is hereafter called "PVA-type resin") film containing an iodine.

Arbitrary suitable resin may be adopted as PVA system resin which forms the above-mentioned PVA system resin film. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85% by mole to 100% by mole, preferably 95.0% by mole to 99.95% by mole, and more preferably 99.0% by mole to 99.93% by mole It is. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA resin having such a degree of saponification, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, gelation may occur.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be determined according to JIS K 6726-1994.

As a method for producing the above-mentioned polarizer, for example, a method (I) of stretching and dyeing a PVA-based resin film alone, a method of stretching and dyeing a laminate (i) having a resin substrate and a polyvinyl alcohol-based resin layer II) and the like. Since the method (I) is a method well known and used in the art, the detailed description is omitted. In the above production method (II), preferably, a laminate (i) having a resin base and a polyvinyl alcohol-based resin layer formed on one side of the resin base is stretched and dyed to form a resin base. And the process of producing a polarizer. The laminate (i) may be formed by applying and drying a coating liquid containing a polyvinyl alcohol resin on a resin base material. In addition, the laminate (i) may be formed by transferring a polyvinyl alcohol-based resin film onto a resin substrate. The details of the above production method (II) are described, for example, in JP-A-2012-73580, which is incorporated herein by reference.

Any appropriate resin film may be employed as the protective film. Examples of materials for forming the protective film include polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as norbornene resins, and olefin resins such as polyethylene and polypropylene. Resin, (meth) acrylic resin, etc. are mentioned. Among them, polyethylene terephthalate (PET) is preferred.

In one embodiment, a (meth) acrylic resin having a glutarimide structure is used as the (meth) acrylic resin.

The protective film and the polarizer are laminated via any appropriate adhesive layer. The resin base material used at the time of polarizer production may be exfoliated before or after laminating the protective film and the polarizer.

The thickness of the protective film is preferably 5 μm to 55 μm, more preferably 10 μm to 50 μm, and still more preferably 15 μm to 45 μm.

B-2. Circularly Polarizing Plate FIG. 4 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 110 includes a circularly polarizing plate 21 as an optical member. The circularly polarizing plate 21 includes a polarizer 1 and a retardation layer 2. In one embodiment, the polarizer 1 is preferably disposed on the side opposite to the laminate A of the retardation layer 2 (that is, the conductive layer). The circularly polarizing plate 21 and the laminate A are laminated via the pressure-sensitive adhesive layer 30, and the pressure-sensitive adhesive layer 30 is in contact with the retardation layer 2 and the conductive layer 13. In another embodiment, a circularly polarizing plate is used as another optical member, and an optical laminate including an optical member, a conductive layer, a liquid crystal layer, and a circularly polarizing plate (retardation layer / polarizer) in this order Body is provided. Also in this embodiment, the polarizer is preferably disposed on the side opposite to the laminate A of the retardation layer (that is, the liquid crystal layer).

In one embodiment, the circularly polarizing plate further comprises a protective film on the side of the polarizer opposite to the retardation layer (not shown). In addition, the circularly polarizing plate may be provided with another protective film (also referred to as an inner protective film: not shown) between the polarizer and the retardation layer. As the polarizer and the protective film, those described in the above section B-1 can be used.

The retardation layer can function as a λ / 4 plate. The in-plane retardation Re (550) of such a retardation layer is preferably 120 nm to 160 nm, more preferably 135 nm to 155 nm. The retardation layer typically has a refractive index ellipsoid of nx> ny ≧ nz.

The Rth (550) of the retardation layer is preferably 120 nm to 300 nm, more preferably 135 nm to 260 nm.

The Nz coefficient of the retardation layer is, for example, 0.9 to 2, preferably 1 to 1.8, and more preferably 1 to 1.7.

The polarizer and the retardation layer are laminated such that the absorption axis of the polarizer and the slow axis of the retardation layer form a predetermined angle. The angle between the absorption axis of the polarizer and the slow axis of the retardation layer is preferably 35 ° to 55 °, more preferably 38 ° to 52 °, and still more preferably 40 ° to 50 °. More preferably, it is 42 ° to 48 °, and particularly preferably 44 ° to 46 °. If the angle is in such a range, a desired circular polarization function can be realized. In addition, when an angle is referred to in the present specification, the angle includes angles in both clockwise and counterclockwise directions unless otherwise specified.

The thickness of the retardation layer may be set to most appropriately function as a λ / 4 plate. In other words, the thickness can be set to obtain a desired in-plane retardation. Specifically, the thickness of the retardation layer is preferably 10 μm to 80 μm, more preferably 10 μm to 60 μm, and most preferably 30 μm to 50 μm.

The retardation layer may have an inverse dispersion wavelength characteristic in which the retardation value increases in accordance with the wavelength of the measurement light, or may indicate a positive wavelength dispersion characteristic in which the retardation value decreases in accordance with the wavelength of the measurement light. It may well exhibit flat wavelength dispersion characteristics in which the retardation value hardly changes depending on the wavelength of the measurement light.

The λ / 4 plate is preferably a stretched film of a polymer film. Specifically, a λ / 4 plate can be obtained by appropriately selecting the type of polymer and stretching treatment (eg, stretching method, stretching temperature, stretch ratio, stretching direction).

Any appropriate resin may be used as the resin for forming the polymer film. Specific examples thereof include resins constituting a positive birefringence film such as cycloolefin resins such as polynorbornene, polycarbonate resins, cellulose resins, polyvinyl alcohol resins, and polysulfone resins. Among them, norbornene resins and polycarbonate resins are preferable. The details of the resin forming the polymer film are described, for example, in JP-A-2014-010291. The description is incorporated herein by reference.

Various products are marketed as said polynorbornene. As a specific example, trade name "Zeonex" manufactured by Nippon Zeon Co., "Zeonor" trade name "Arton" manufactured by JSR, trade name "Topath" manufactured by TICONA, trade name manufactured by Mitsui Chemicals, Inc. "APEL" is mentioned.

Examples of the stretching method include transverse uniaxial stretching, fixed end biaxial stretching, and sequential biaxial stretching. As a specific example of the fixed end biaxial stretching, there is a method of stretching in the short direction (lateral direction) while traveling the polymer film in the longitudinal direction. This method may be apparently transverse uniaxial stretching. Also, oblique stretching can be employed. By adopting oblique stretching, it is possible to obtain a long stretched film having an alignment axis (slow axis) at a predetermined angle with respect to the width direction.

The thickness of the stretched film is typically 5 μm to 80 μm, preferably 15 μm to 60 μm, and more preferably 25 μm to 45 μm.

B-3. Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive layer is formed of any appropriate pressure-sensitive adhesive. In one embodiment, the pressure-sensitive adhesive contains a tacky resin, and examples of the resin include acrylic resins, acrylic urethane resins, urethane resins, silicone resins and the like. Among them, preferred is an acrylic pressure-sensitive adhesive containing an acrylic resin.

The pressure-sensitive adhesive may further contain any appropriate additive, as needed. Examples of the additive include a crosslinking agent, a tackifier, a plasticizer, a pigment, a dye, a filler, an antiaging agent, a conductive material, an ultraviolet absorber, a light stabilizer, a release regulator, a softener, and a surfactant. Flame retardants, antioxidants, etc. As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a peroxide type crosslinking agent, a melamine type crosslinking agent, a urea type crosslinking agent, a metal alkoxide type crosslinking agent, a metal chelate type crosslinking agent, a metal salt type crosslinking agent, A carbodiimide type crosslinking agent, an oxazoline type crosslinking agent, an aziridine type crosslinking agent, an amine type crosslinking agent etc. are mentioned.

The thickness of the pressure-sensitive adhesive layer is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm.

B-4. Other Layers The optical laminate may be provided with any appropriate other layer, as needed. As said other layer, a hard-coat layer, an anti glare layer, an anti-reflective layer, a color filter layer etc. are mentioned, for example.

C. Method of Producing Optical Laminate The method of producing an optical laminate of the present invention comprises transferring a laminate A including a liquid crystal layer and a conductive layer to an optical member from the conductive film for transfer. In one embodiment, in this manufacturing method, the conductive layer and the optical member are laminated via an adhesive layer. As the conductive film for transfer, the optical member and the pressure-sensitive adhesive layer, those described in the above section A and section B can be used.

After transferring the laminate A to the optical member, another optical member may be laminated on the liquid crystal layer of the laminate A via the pressure-sensitive adhesive layer.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The thickness was measured using a digital gauge cordless type “DG-205” manufactured by Ozaki Mfg.

Example 1
A liquid crystal layer was formed by the following method on a polyethylene terephthalate film (trade name "Panapeel", thickness: 38 μm, manufactured by PANAC Co., Ltd.) subjected to release treatment as a temporary support.
20 parts by weight of a side chain-type liquid crystal polymer represented by the following chemical formula (I) (numbers 65 and 35 in the formula indicate mole% of monomer units and is represented by a block polymer for convenience: weight average molecular weight 5000) 80 parts by weight of a polymerizable liquid crystal (manufactured by BASF: trade name: Paliocolor LC 242) exhibiting a nematic liquid crystal phase and 5 parts by weight of a photopolymerization initiator (Cibas Specialty Chemicals: trade name: Irgacure 907) dissolved in 200 parts by weight of cyclopentanone Thus, a liquid crystal coating liquid was prepared. Then, the coating solution was applied by a bar coater to the release-treated surface of a PET film (temporary support), and the liquid crystal was oriented by heating and drying at 80 ° C. for 4 minutes. The liquid crystal layer was irradiated with ultraviolet rays to cure the liquid crystal layer, whereby a liquid crystal solidified layer (thickness: 0.58 μm) was formed on the PET film (temporary support). The in-plane retardation Re (550) of this liquid crystal layer is 0 nm, and the retardation Rth (550) in the thickness direction is -71 nm (nx: 1.5326, ny: 1.5326, nz: 1.6550), nz The refractive index characteristic of> nx = ny was shown.

Then, the laminate composed of the temporary support and the liquid crystal layer was put into a sputtering apparatus, and an amorphous indium tin oxide layer with a thickness of 30 nm was formed on the surface of the liquid crystal layer. Thereafter, the indium tin oxide was converted from amorphous to crystalline by heat treatment at 130 ° C. for 90 minutes to obtain a conductive film for transfer (conductive layer / liquid crystal layer / temporary support).
Using the obtained conductive film for transfer, a laminate A composed of a temporary support, a conductive layer and a liquid crystal layer, and a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive are used to form a PET film (thickness: 23 μm) Then, the temporary support was peeled off to obtain a sample for evaluation of bending resistance (liquid crystal layer / conductive layer / pressure-sensitive adhesive layer / PET substrate).

Comparative Example 1
Thermosetting resin (melamine resin: alkyd) comprising a melamine resin, an alkyd resin and an organic silane condensate on one surface of a polyethylene terephthalate (PET) film (Mitsubishi Chemical Co., Ltd., trade name "Diafoil", thickness: 23 μm) Resin: organic silane condensate (weight ratio) = 2: 2: 1) was applied and cured to form a 35 nm thick transparent dielectric layer (refractive index: 1.54).
Then, the PET film with a transparent dielectric layer was introduced into a take-up type sputtering apparatus, and an indium tin oxide layer (thickness: 30 nm) was formed on the surface of the transparent dielectric layer as a conductive layer. Sputtering was performed using a sintered body consisting of 97% by weight of indium oxide and 3% by weight of tin oxide in an atmosphere of 0.4 Pa consisting of 98% argon gas and 2% oxygen.
The laminate obtained as described above is attached to a PET film (thickness: 23 μm) via a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive, and a sample for evaluating bending resistance (PET base material / dielectric material Layer / conductive layer / adhesive layer / PET substrate) was obtained.

Comparative Example 2
0.16 parts by weight of a plurality of monodispersed particles (manufactured by Soken Chemical Co., Ltd., trade name “MX180-TAN”, refractive index: 1.495) having an average particle diameter of 1.8 μm, and a binder resin (manufactured by DIC, trade name) Coating composition A containing 100 parts by weight of UNIDIC ", refractive index: 1.51) and a solvent (ethyl acetate) was prepared. Then, on one side of a long base film (Nippon Zeon Co., Ltd., trade name "ZEONOR", thickness: 40 μm), the thickness of the flat portion after drying of the above-mentioned coating composition A using a gravure coater is 1.0 μm The coating was dried by heating at 80 ° C. Then, the antiblocking layer was formed by irradiating the ultraviolet-ray of 250 mJ / cm < ² > of integrated light quantity with a high pressure mercury lamp.
Subsequently, a coating composition B was prepared by diluting a binder resin (manufactured by DIC, trade name "UNIDIC", refractive index 1.51) with ethyl acetate. Coating composition B is applied to the surface of the long base film opposite to the antiblocking layer using a gravure coater so that the thickness of the flat part after drying is 1.0 μm, and heated at 80 ° C. The coating was dried by Then, the hard coat layer was formed by irradiating the ultraviolet-ray of 250 mJ / cm < ² > of accumulated light quantities with a high pressure mercury lamp.
Next, on the surface of the hard coat layer, an organic-inorganic composite material comprising a refractive index modifier (trade name "Opster Z7412" manufactured by JSR Corporation, zirconia particles having a median diameter of 40 nm as an inorganic component and a refractive index of 1.62 ) Was applied using a gravure coater, and the coating was dried by heating at 60.degree. After that, ultraviolet rays of 250 mJ / cm ² of integrated light quantity were irradiated with a high pressure mercury lamp to perform curing treatment, thereby forming an optical adjustment layer having a thickness of 115 nm and a refractive index of 1.62.
Thereafter, a long base film having an antiblocking layer, a hard coat layer, and an optical adjustment layer laminate is introduced into a take-up type sputtering apparatus, and an indium tin oxide layer (a conductive layer) is formed on the surface of the COP base. Thickness: 30 nm). Sputtering was performed using a sintered body consisting of 97% by weight of indium oxide and 3% by weight of tin oxide in an atmosphere of 0.4 Pa consisting of 98% argon gas and 2% oxygen.
The laminate obtained as described above is attached to a PET film (thickness: 23 μm) via a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive, and a sample for evaluating bending resistance (COP base material / optical adjustment A layered long substrate film / conductive layer / adhesive layer / PET substrate) was obtained.

<Evaluation 1>
(Bending resistance test)
The evaluation samples obtained in Example 1 and Comparative Examples 1 and 2 were subjected to a bending tolerance test. The results are shown in Table 1. The test method of the bending resistance test is as follows.
The resistance value change after the bending test of each evaluation sample was measured using an automatic bending tester manufactured by Yuasa System Instruments Co., Ltd. and a resistance value tester to evaluate the bending resistance.
Regarding the bending test, the test diameter was 5 mm in diameter, and the bending was performed so that the PET substrate side bonded via the pressure-sensitive adhesive was on the bending outer surface side.
As a result of the above-mentioned test, although the change in the resistance value was not observed even after the bending of 200,000 times in Example 1, the resistance value was large in the comparative example 1 and the comparative example 2 due to the bending less than that number. It confirmed that it changed. A graph of the results is shown in FIG.

Example 2
(Preparation of polarizer)
After a long polyvinyl alcohol film is dyed in an aqueous solution containing iodine, it is uniaxially stretched 6 times between rolls having different speed ratios in an aqueous solution containing boric acid, and a long sheet having an absorption axis in the longitudinal direction -Shaped polarizer (thickness: 12 μm) was obtained. The elongated polarizer was stretched and then wound to form a wound body.

(Preparation of protective film)
As a protective film, a long triacetyl cellulose film (thickness 40 μm, manufactured by Konica Minolta, trade name: KC4UYW) was used. This protective film was prepared as a wound body. The in-plane retardation Re (550) of the protective film was 5 nm, and the retardation Rth (550) in the thickness direction was 45 nm.

(Preparation of retardation film)
A commercially available retardation film (trade name “Pure Ace WR”, thickness: 51 μm, manufactured by Teijin Ltd.) showing wavelength dependency of reverse dispersion was used. The in-plane retardation Re (550) of this retardation film was 147 nm, and Re (450) / Re (550) was 0.89.

(Preparation of circularly polarizing plate)
The said polarizer, protective film, and retardation film were respectively cut out to 200 mm x 300 mm. The polarizer and the protective film were attached to each other via a polyvinyl alcohol-based adhesive. The laminate of the polarizer / protective film and the retardation film are pasted so that the polarizer and the retardation film are adjacent via the acrylic pressure-sensitive adhesive layer, and the constitution of the protective film / polarizer / retardation layer A circularly polarizing plate (thickness: 105 μm) was produced. The retardation film was placed so that its slow axis and the absorption axis of the polarizer make an angle of 45 ° when they were laminated.

(Production of optical laminate)
In the same manner as in Example 1, a conductive film for transfer was obtained. Using the conductive film for transfer, from the temporary support, the laminate A composed of the conductive layer and the liquid crystal layer, through the pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive, the retardation film of the circularly polarizing plate Transfer to the side to obtain an optical laminate (circularly polarizing plate (protective film / polarizer / retardation layer) / adhesive layer / conductive layer / liquid crystal layer). This optical laminate was as thin as 110 μm in total thickness, and was bendable without damaging each layer.
Furthermore, the liquid crystal layer side of the said optical laminated body was stuck to the organic electroluminescent panel, and the optical characteristic at the time of the panel non-lighting of the optical laminated body was confirmed. In this configuration, it was confirmed that the conductive layer laminated on the liquid crystal layer can enjoy the reflection preventing effect of the circularly polarizing plate, and can realize excellent blackness.

Comparative Example 3
In the same manner as Comparative Example 1, a laminate provided with a PET substrate, a dielectric layer and a conductive layer in this order was obtained. The PET substrate side of this laminate was attached to the same protective film of the circularly polarizing plate as in Example 2 via the pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive. Furthermore, the liquid crystal coating liquid prepared in Example 1 is applied to the retardation film side of the circularly polarizing plate by the same method as in Example 1 to form a liquid crystal layer, and an optical laminate (conductive layer A dielectric layer / PET base material / circularly polarizing plate (protective film / polarizer / retardation layer) / liquid crystal layer) was obtained. The optical laminate had a total thickness of 135 μm.
Furthermore, the liquid crystal layer side of the said optical laminated body was stuck on the organic electroluminescent panel, and the reflection preventing ability of the optical laminated body was confirmed. In the optical laminate, the reflection of light by the conductive layer was significantly confirmed.

[Reference Example 1]
In the same manner as in Comparative Example 2, a laminate provided with a COP substrate, a long base film with an optical adjustment layer, and a conductive layer in this order was obtained.
The liquid crystal coating liquid prepared in Example 1 was coated on the retardation film side of the same circularly polarizing plate as in Example 2 in the same manner as in Example 1 to form a liquid crystal layer.
Next, the conductive layer side of the laminate is attached to the liquid crystal layer through the pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive, and the optical laminate (circularly polarizing plate (circular film (protective film / polarizer / retardation layer)) ) / Liquid crystal layer / conductive layer / long base film with optical adjustment layer / COP base material). The optical laminate had a total thickness of 150 μm.
The liquid crystal layer side of the optical laminate was attached to the organic EL panel, and the antireflection performance of the optical laminate was confirmed. The optical laminate exhibited antireflective ability.

10 Conductive Film for Transfer 11 Temporary Support 12 Liquid Crystal Layer 13 Conductive Layer 20 Optical Member

Claims

A conductive film for transfer, comprising a temporary support, a liquid crystal layer provided so as to be removable from the temporary support, and a conductive layer in this order.
The conductive film for transfer according to claim 1, wherein the conductive layer is directly laminated on the liquid crystal layer.
The conductive film for transfer according to claim 1, wherein the refractive index characteristic of the liquid crystal layer shows a relationship of nz> nx ≧ ny.
The conductive film for transfer according to claim 1, wherein the liquid crystal layer has a thickness of 0.1 μm to 10 μm.
The conductive film for transfer according to claim 1, wherein the conductive layer is composed of a metal oxide.
The conductive film for transfer according to claim 1, wherein the conductive layer is patterned.
An optical member, a pressure-sensitive adhesive layer, a conductive layer according to claim 1, 5 or 6, and a liquid crystal layer according to claim 1, 3 or 4 in this order,
The conductive layer is directly laminated on the liquid crystal layer,
Optical laminate.
The optical laminated body of Claim 7 whose said optical member is a polarizing plate.
The optical member is a circularly polarizing plate,
The circularly polarizing plate includes a polarizer and a retardation layer functioning as a λ / 4 plate,
The polarizer is disposed on the opposite side of the retardation layer to the conductive layer.
The optical laminated body of Claim 7.
The optical laminate according to claim 7, further comprising another optical member on the side opposite to the conductive layer of the liquid crystal layer.
The other optical member is a circularly polarizing plate,
The circularly polarizing plate includes a polarizer and a retardation layer functioning as a λ / 4 plate,
The polarizer is disposed on the opposite side of the retardation layer to the liquid crystal layer.
The optical laminated body of Claim 10.
A touch device comprising the optical laminate according to claim 7.
A method for producing an optical laminate, comprising transferring the laminate A including the liquid crystal layer and the conductive layer to an optical member from the conductive film for transfer according to claim 1.