TW201443926A - Transparent conductive film - Google Patents

Abstract

A transparent conductive film comprising the following: a first transparent film; a first transparent conductive layer that is formed on one surface of the first transparent film and is not patterned; a transparent curable adhesive layer or pressure-sensitive adhesive layer laminated to the other surface of the first transparent film; and a second transparent film laminated to the surface of the transparent curable adhesive layer or pressure-sensitive adhesive layer facing away from the first transparent film. The second transparent film exhibits a heat-shrinkage percentage (at 140 DEG C for 90 minutes) of at most 0.4% in both the lengthwise direction (MD) of the film and the widthwise direction (TD) of the film.

Description

Transparent conductive film

The present invention relates to a transparent conductive film which can be used for a capacitive touch panel or the like.

Background technique

A transparent conductive film in which a patterned transparent conductive layer is formed on a laminate in which two films are bonded is known (for example, Patent Document 1). The two films were laminated with a very thick pressure-sensitive adhesive (adhesive) layer having a thickness of about 20 μm. When such a transparent conductive film is used for a resistive touch panel, since the pressure-sensitive adhesive layer has cushioning properties, the durability of the pen-type input and the surface pressure durability are improved.

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-76432

Summary of invention

The patterned transparent conductive layer is usually formed by etching, but for the conventional transparent conductive film, when the etching step is heated, the portion having the transparent conductive pattern and the portion having no portion are received. The shrinkage rate is different, and the transparent conductive film is prone to waviness.

An object of the present invention is to realize a transparent conductive film which is excellent in adhesion between a first transparent film and a second transparent film and has less waviness than the conventional technique.

The inventors of the present invention have carefully investigated the cause of the waviness of the transparent conductive film, and as a result, have found the following points: whether the transparent conductive film is corrugated or not, and in particular, the heat shrinkage rate of the second transparent film. Great impact. As a result of further investigation, it was found that when the second transparent film having a reduced heat shrinkage ratio is used, specifically, the second transparent film is placed in a film at a temperature of 140 ° C for 90 minutes, regardless of the film length (MD). When the second transparent film having a thermal shrinkage ratio of 0.4% or less in any direction in the film width direction (TD) is used, the corrugation of the transparent conductive film can be effectively prevented. The present invention has been completed based on the above findings, and has the following constitution.

That is, the present invention relates to a transparent conductive film characterized by comprising: a first transparent film; a first transparent conductive layer formed on one surface of the first transparent film and not patterned; and a transparent hardening type a layer of the agent or an adhesive layer laminated on the other surface of the first transparent film; and a second transparent film laminated on the first transparent film at the position of the transparent curing adhesive layer or the adhesive layer On the opposite side, the second transparent film has a heat shrinkage ratio (140 ° C, 90 minutes) in the film length direction (MD) and the film width direction (TD) of 0.4% or less.

In the above transparent conductive film, the first transparent conductive layer is preferably patterned.

In the transparent conductive film, the thickness of the first transparent film is preferably 15 μm to 75 μm.

In the transparent conductive film, the thickness of the second transparent film is preferably 15 μm to 200 μm.

The transparent conductive film is preferably one in which a second transparent conductive layer is formed on a surface of the second transparent film on the opposite side of the transparent cured adhesive layer or the adhesive layer.

In the transparent conductive film, the thickness of the transparent curable adhesive layer or the adhesive layer is preferably 0.01 μm or more and less than 50 μm.

In the transparent conductive film, the material for forming the first transparent film and the material for forming the second transparent film are preferably any of polyethylene terephthalate, polycycloolefin, and polycarbonate.

In the transparent conductive film, the material for forming the first transparent conductive layer is preferably indium tin oxide (ITO: Indium Tin Oxide), indium zinc oxide, indium oxide-zinc oxide composite oxide, polythiophene, or nano. Any one of a carbon tube, an aluminum zinc oxide, a gallium zinc oxide, a fluorine zinc oxide, a fluorine indium oxide, a antimony tin oxide, a fluorine tin oxide or a phosphorus tin oxide.

The difference between the heat shrinkage ratio measured in the state in which the first transparent conductive layer is removed and the heat shrinkage ratio measured in the state before the removal of the first transparent conductive layer is preferably less than 0.15%.

According to the present invention, it is possible to obtain a laminated transparent conductive film which is excellent in adhesion between the first transparent film and the second transparent film and has less waviness. Further, the capacitive touch panel using the transparent conductive film of the present invention is more excellent in touch sensitivity than the capacitive touch panel using the conventional transparent conductive film.

10‧‧‧Transparent conductive film

11‧‧‧1st transparent film

12A‧‧‧Unpatterned transparent conductive layer

12‧‧‧ patterned transparent conductive layer

13‧‧‧Transparent hardening adhesive layer or adhesive layer

14‧‧‧2nd transparent film

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view and a cross-sectional view showing an example of an unpatterned transparent conductive film of the present invention.

Fig. 2 is a top plan view and a cross-sectional view showing an example of the patterned transparent conductive film of the present invention.

Form for implementing the invention

[Transparent Conductive Film]

An example of an embodiment of the unpatterned transparent conductive film of the present invention is shown in Fig. 1. The transparent conductive film 10 of this embodiment has a first transparent film 11 , a first transparent conductive layer 12A that is not patterned, a transparent cured adhesive layer 13 , and a second transparent film 14 . The first transparent conductive layer 12A is formed on one surface (upper surface in FIG. 1) of the first transparent film 11. The transparent hardening type adhesive layer 13 is laminated on the other surface of the first transparent film 11 (below in FIG. 1). The second transparent film 14 is laminated on the surface of the transparent cured adhesive layer 13 on the opposite side of the first transparent film 11 (lower side in FIG. 1).

In the transparent conductive film 10 of the present invention, the first transparent film 11 and the second transparent film 14 are laminated through the transparent curing adhesive layer 13. The thickness of the transparent hardening type adhesive layer 13 is preferably 0.01 μm or more and less than 10 μm. The first transparent film 11 of the transparent conductive film 10 of the present invention is preferably thinner than the second transparent film 14. At this time, the thin first transparent film 11 can be permeable to the thicker and thin transparent curing type adhesive layer 13 to be lined with the thicker second transparent film 14, and the thicker second transparent film 14 is resistant to shrinkage. High in nature and not prone to ripples. Thereby, the transparent conductive film 10 of the present invention can more effectively suppress the occurrence of waviness.

In the present invention, the difference between the heat shrinkage ratio measured in the state where the first transparent conductive layer has been removed and the heat shrinkage ratio measured in the state before the first transparent conductive layer is removed is preferably less than 0.15%. That is, regardless of the presence or absence of the transparent conductive layer, by using a material having no difference in heat shrinkage ratio, even a film obtained by patterning a transparent conductive laminated film provided with a transparent conductive layer can suppress waviness. The difference in the aforementioned shrinkage ratio is preferably 0.10% or less.

[1st transparent film]

Although the first transparent film 11 is not particularly limited, various plastic films having transparency can be used. The material of the plastic film may, for example, be polyester such as polyethylene terephthalate or polyethylene naphthalate, polycycloolefin, polyacetate, polyether oxime, polycarbonate, polyamine, Polyimine, (meth)acrylic polymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, polyphenylene sulfide, and the like. Among these materials, from the viewpoint of heat resistance and optical properties, the use of a polyester (particularly polyethylene terephthalate), a polycycloolefin or a polycarbonate is preferred in the present invention.

The thickness of the first transparent film 11 is usually 15 to 75 μm, and preferably 20 to 75 μm, more preferably 23 to 50 μm. When the thickness of the first transparent film 11 is less than 15 μm, the mechanical strength of the film substrate is insufficient, and it is likely to be broken. crack. On the other hand, once the thickness exceeds 75 μm, the amount of input during the film forming process of the transparent conductive layer may be reduced, or the disadvantages may be caused in the step of removing gas or moisture, which may impair the productivity.

The first transparent film 11 may be subjected to an etching treatment or a primer treatment such as sputtering, corona discharge, flame, ultraviolet ray irradiation, electron beam irradiation, chemical conversion, and oxidation on the surface to improve the transparent conductive layer provided thereon. Or the adhesion of the undercoat layer to the first transparent film. Further, before the first transparent conductive layer 12A or the undercoat layer (not shown in FIG. 1) is provided, it may be dedusted and cleaned by solvent washing or ultrasonic cleaning as needed.

[1st transparent conductive layer]

The constituent material of the first transparent conductive layer 12A is not particularly limited, and may be selected from the group consisting of indium, tin, zinc, gallium, germanium, titanium, hafnium, zirconium, magnesium, aluminum, gold, silver, copper, palladium, and tungsten. At least 1 in the group consisting of polythiophene, carbon nanotubes, aluminum zinc oxide, gallium zinc oxide, fluorine zinc oxide, fluorine indium oxide, antimony tin oxide, fluorine tin oxide, and phosphorus tin oxide. a metal oxide of a metal. The metal oxide may further contain a metal atom shown in the above group as needed. For example, indium tin oxide (ITO), indium zinc oxide or indium oxide-zinc oxide composite oxide can be applied, and ITO is particularly preferably used. Further, a conductive polymer such as polythiophene or a carbon nanotube or the like can also be used.

The thickness of the first transparent conductive layer 12A is not particularly limited. However, in order to form a continuous film having good electrical conductivity with a surface resistance of 1 × 10 ³ Ω/□ or less, the thickness is preferably 10 nm or more. The thickness is preferably from 10 to 300 nm, more preferably from 15 to 100 nm. When the film thickness is too thick, transparency is lowered, and the like, and therefore it is preferably 15 to 35 nm, more preferably 20 to 30 nm.

The method of forming the first transparent conductive layer 12A is not particularly limited, and a conventionally known method can be employed. Specific examples thereof include a vacuum vapor deposition method, a sputtering method, an ion plating method, and a coating method. In addition, an appropriate method can be used in accordance with the necessary film thickness.

<Undercoat>

In the present invention, an undercoat layer may be provided on the first transparent film. The undercoat layer may be formed of an inorganic substance, an organic substance or a mixture of an inorganic substance and an organic substance. The inorganic substance may, for example, be an inorganic substance such as NaF, Na ₃ AlF ₆ , LiF, MgF ₂ , CaF ₂ , BaF ₂ , SiO ₂ , LaF ₃ , CeF ₃ or Al ₂ O ₃ . When the undercoat layer is formed of an inorganic material, it can be formed by a dry process such as a vacuum deposition method, a sputtering method, or an ion plating method, or a wet method (coating method). Further, examples of the organic substance include an acrylic resin, a urethane resin, a melamine resin, an alkyd resin, a decane-based polymer, and an organic decane condensate. At least one of these organic substances may be used. As the organic substance, a thermosetting resin composed of a mixture of a melamine resin, an alkyd resin and an organic decane condensate is particularly preferably used.

The thickness of the undercoat layer is not particularly limited, but is usually from 1 to 300 nm, and preferably from 5 to 300 nm, from the viewpoint of optical design and prevention of the effect of generating oligomers from the first transparent film. Further, when the undercoat layer is provided in two or more layers, the thickness of each layer is about 5 to 250 nm, and preferably 10 to 250 nm.

[Transparent hardening type adhesive layer]

The transparent curable adhesive layer 13 of the transparent conductive film 10 of the present embodiment is laminated on the surface of the first transparent film 11 which does not have the unpatterned transparent conductive layer 12A. That is, the transparent hardening type adhesive layer 13 is disposed at The first transparent film 11 and the second transparent film 14 are interposed. The formation of the transparent hardening type adhesive layer 13 can be applied to a radical hardening type adhesive. The radical hardening type adhesive can be exemplified by an active energy ray-curable adhesive such as an electron beam curing type or an ultraviolet curing type. Among them, an active energy ray-curing type which can be hardened in a short period of time is preferable, and an ultraviolet-curable type adhesive which can be hardened with low energy is more preferable.

The ultraviolet curable adhesive can be roughly classified into a radical polymerization hardening type adhesive and a cationic polymerization type adhesive. Further, a radical polymerization hardening type adhesive can also be used as a thermosetting type adhesive.

The curable component of the radical polymerization hardening type adhesive may, for example, be a compound having a (meth)acryl fluorenyl group and a compound having a vinyl group. As the curable component, either monofunctional or difunctional or the like can be used. In addition, these curable components may be used alone or in combination of two or more. For example, the hardening component is preferably a compound having a (meth) acrylonitrile group.

Specifically, the compound having a (meth) acrylonitrile group may, for example, be methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate or isopropyl (meth) acrylate. , 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, dibutyl (meth) acrylate, (methyl ) tert-butyl acrylate, n-amyl (meth) acrylate, third amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethyl butyl (methyl) Acrylate, n-hexyl (meth)acrylate, hexadecyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl (meth)acrylate -2-propylpentyl ester, (meth)acrylic acid A (meth)acrylic acid (carbon number 1 to 20) alkyl ester such as octadecyl ester.

Further, examples of the compound having a (meth)acryl fluorenyl group include a cycloalkyl (meth)acrylate (for example, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), (meth)acrylic acid. Aralkyl esters (such as benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (such as 2-isodecyl (meth) acrylate, 2-norbornyl methyl (meth) acrylate Ester, 5-northene-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc.), hydroxyl-containing (meth) acrylate Esters (for example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (methyl) methacrylate, etc.), Alkoxy or phenoxy (meth) acrylates (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxy Ethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), containing a ring Alkyl (meth) acrylates (for example, glycidyl (meth) acrylate), halogen-containing (meth) acrylates Classes (eg 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, ( Hexafluoropropyl methacrylate, octafluoropentyl (meth)acrylate, heptafluorodecyl (meth)acrylate, etc.), alkylaminoalkyl (meth) acrylate (eg (methyl)) Dimethylaminoethyl acrylate, etc.).

Further, examples of the compound having a (meth) acrylonitrile group other than the above may, for example, be hydroxyethyl acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide (SP value 22.9), A guanamine-containing monomer such as N-ethoxymethyl acrylamide or (meth) acrylamide. Acryl sulfhydryl A nitrogen-containing monomer or the like such as a phenyl group.

In addition, the curable component of the radical polymerization-curable adhesive may, for example, be a compound having a polymerizable double bond such as a plurality of (meth)acryl fluorenyl groups or a vinyl group, and the compound may be mixed as a crosslinking component to an adhesive. In the ingredients. Examples of the curable component which will be a component of the crosslinking component include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, and cyclic trimethylolpropane contraction. Aldehyde acrylate, two Alkylene glycol diacrylate, EO modified diglycerin tetraacrylate, ARONIX M-220 (manufactured by Toagosei Co., Ltd.), LIGHT ACRYLATE 1, 9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DGE-4A (total LIGHT ACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), and CD-536 (manufactured by Sartomer Co., Ltd.). Further, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like can be exemplified as needed.

The radical polymerization hardening type adhesive contains the curable component, but a radical polymerization initiator may be added in addition to the above components depending on the type of curing. When the above-mentioned adhesive is an electron beam curing type, the above-mentioned adhesive is not particularly required to contain a radical polymerization initiator, but when an ultraviolet curing type or a thermosetting type is used, a radical polymerization initiator can be used. The amount of the radical polymerization initiator to be used is usually from 0.1 to 10 parts by weight, and preferably from 0.5 to 3 parts by weight, per 100 parts by weight of the curable component. In addition, a radical sensitizing agent represented by a carbonyl compound or the like may be added as needed, and the curing speed and sensitivity of the electron beam can be improved. The photosensitizer is usually used in an amount of 0.001 to 10 weight per 100 parts by weight of the curable component. The amount of the component is preferably from 0.01 to 3 parts by weight.

The hardening component of the cationic polymerization hardening type adhesive may, for example, be a compound having an epoxy group or an oxo group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various hardening epoxy compounds generally known can be used. Preferred epoxy compounds include, for example, a compound having at least two epoxy groups and at least one aromatic ring in the molecule; and having at least two epoxy groups in the molecule and at least one epoxy group formed in the constituent lipid. a compound or the like between two adjacent carbon atoms of the ring.

In addition, when the transparent hardening type adhesive layer is to be formed, examples of the water-based curing adhesive include vinyl polymer, gelatin, vinyl latex, polyurethane, isocyanate, polyester, and epoxy. Department and so on. The adhesive layer formed of these water-based adhesives can be formed as a coating dry layer of an aqueous solution or the like. When the aqueous solution is prepared, a crosslinking agent or other additives and a catalyst such as an acid can be added as needed.

The water-based adhesive is preferably an adhesive containing a vinyl polymer or the like, and the vinyl polymer is preferably a polyvinyl alcohol-based resin. Moreover, from the viewpoint of improving durability, it is more preferable to use a polyvinyl alcohol-based resin having an ethylene glycol group as a binder of a polyvinyl alcohol-based resin. Further, as the crosslinking agent which can be blended into the polyvinyl alcohol-based resin, a compound having two or more functional groups reactive with the polyvinyl alcohol-based resin can be used. For example, boric acid or borax, a carboxylic acid compound, an alkyl diamine; an isocyanate; an epoxy; a monoaldehyde; a dialdehyde; an amine-formaldehyde resin; and a salt of a divalent metal or a trivalent metal. And its oxides.

If necessary, form an adhesive for the hardened adhesive layer Additives may also be suitably included. Examples of the additive include a coupling agent such as a decane coupling agent and a titanium coupling agent, an adhesion promoter represented by an alkoxyethane, an additive for improving the wettability with a transparent protective film, and an acryloxy group. Compounds, hydrocarbons (natural, synthetic resins), etc., additives for improving mechanical strength and processability, ultraviolet absorbers, aging inhibitors, dyes, processing aids, ion scavengers, oxidation inhibitors, and viscosity-increasing Agents, fillers (other than metal compound fillers), plasticizers, leveling agents, foaming inhibitors, charge inhibitors, heat stabilizers, stabilizers such as hydrolysis stabilizers, and the like.

The coating method of the subsequent agent can be based on the viscosity of the adhesive and the thickness of the target. Come to the appropriate choice. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or indirect), a bar-reverse coater, a roll coater, a die coater, and a rod. Coating machine and rod coating machine. In addition to this, the coating can be suitably used in the form of a dipping method or the like.

Further, the thickness of the transparent curable adhesive layer is preferably 0.01 μm or more and less than 50 μm. More preferably, it is 0.1 μm or more and less than 5 μm, and more preferably 0.3 μm or more and less than 4 μm.

In addition, the embodiment shown in FIG. 1 shows an example in which the transparent curing type adhesive layer 13 is disposed between the first transparent film 11 and the second transparent film 14, but an adhesive layer may be disposed instead of the transparent curing type adhesive. Layer 13. The adhesive layer can be used without particular limitation as long as it has transparency. Specifically, for example, a polymer having the following polymers as a base polymer can be appropriately selected and used: an acrylic polymer, a polyoxymethylene polymer, a polyester, a polyurethane, a polyamide, a polyethylene. Ether, vinyl acetate / vinyl chloride Polymers such as rubbers such as polymers, modified polyolefins, epoxy resins, fluorine resins, natural rubbers, and synthetic rubbers. Among them, an acrylic adhesive is particularly preferably used from the viewpoint of excellent optical transparency, adhesion properties such as moderate wettability, cohesiveness, and adhesion, and excellent weather resistance and heat resistance.

Depending on the type of adhesive of the adhesive layer constituting material, it is also possible to increase the anchoring force with the substrate by using a suitable adhesive primer. Therefore, when such an adhesive is used, it is preferable to use an adhesive primer for the first transparent film 11.

The aforementioned adhesive layer may contain a crosslinking agent in response to the base polymer. Further, the adhesive layer may contain a filler such as a resin such as a natural product or a composite, a glass fiber or a glass bead, a metal powder or other inorganic powder, a filler, a pigment, a colorant, an oxidation preventive agent, etc. as needed. Additives. Further, it may be made to contain transparent fine particles to form a light diffusing adhesive layer 3.

The above-mentioned adhesive layer is usually used in the form of an adhesive solution which is obtained by dissolving or dispersing a base polymer or a composition thereof in a solvent, and has a solid concentration of about 10 to 50% by weight. The solvent may be appropriately selected depending on the kind of the adhesive, and an organic solvent such as toluene or ethyl acetate or water or the like may be used.

Further, the thickness of the above-mentioned adhesive layer is preferably 0.01 μm or more and less than 50 μm. More preferably, it is 1 μm or more and less than 30 μm, and more preferably 3 μm or more and less than 25 μm.

[2nd transparent film]

The second transparent film 14 of the transparent conductive film 10 of the present invention is laminated on the opposite side of the first transparent film 11 of the transparent curing type adhesive layer 13. The thickness t3 of the second transparent film 14 is preferably thicker than the thickness t1 of the first transparent film 11. It should be 1.5 times to 6 times, more preferably 2 times to 6 times, and particularly preferably 3 times to 5 times. When the thickness t3 of the second transparent film 14 is thinner than 1.5 times the thickness t1 of the first transparent film 11, the shrinkage resistance of the transparent conductive film 10 is insufficient, and it is difficult to suppress the occurrence of ripples. When the thickness t3 of the second transparent film 14 exceeds 6 times the thickness t1 of the first transparent film 11, the thickness t of the transparent conductive film 10 becomes too thick, and the transparency is lowered. Or the thickness becomes too large and it is difficult to mount it on the touch panel. In consideration of the thickness t1 of the first transparent film 11 and the above magnification, the thickness t3 of the second transparent film 14 is preferably 15 μm to 200 μm, more preferably 45 μm to 150 μm. In the transparent conductive film 10 of the present invention, by controlling the thickness t3 of the second transparent film 14 within the above range, the shrinkage resistance can be improved and the waviness can be reduced. Further, when the transparent conductive film 10 of the present invention is used as an upper electrode of a capacitive touch panel, and a lower electrode (not shown) is laminated under the transparent conductive film 10, the interval between the electrodes can be appropriately adjusted. The expansion makes the touch feel good.

As the material for forming the second transparent film 14, a material excellent in transparency and heat resistance is preferably used. The material for forming the second transparent film 14 may, for example, be polyethylene terephthalate, polycycloolefin or polycarbonate. The second transparent film 14 may be provided with an easy-to-attach layer (not shown) or a hard coat layer (not shown) for imparting scratch resistance on the surface (single or both sides). The easy-adhesion layer and the hard coat layer are the same as the easy-adhesion layer and the hard coat layer of the first transparent film 11.

The invention is characterized in that the film length of the second transparent film (MD) and the film shrinkage direction (TD) have a heat shrinkage ratio (140 ° C, 90 minutes) of 0.4% or less. The heat shrinkage ratio is a value measured by heating a single sheet of the second transparent film at 140 ° C for 90 minutes. In order to more effectively prevent the corrugation of the transparent conductive film, the heat shrinkage ratio (140 ° C, 90 minutes) of MD and TD is preferably 0.3% or less.

[Second transparent conductive layer]

Further, in the second transparent film, the second transparent conductive layer may be provided on the other surface on which the transparent curing type adhesive layer or the adhesive layer is not provided. The second transparent conductive layer can be formed by the same method as the first transparent conductive layer. Further, the thickness of the second transparent conductive layer may be the same as the thickness of the first transparent conductive layer.

1 shows a top view and a cross-sectional view showing an example of a non-patterned transparent conductive film, but when the transparent conductive film of the present invention is used for a capacitive touch panel or the like, for example, transparent conductivity The first transparent conductive layer of the film is patterned as shown in FIG. The patterned transparent conductive layer 12 can be used as a sensor for detecting a touch position. The patterned transparent conductive layer 12 is usually electrically connected to a drawn wiring (not shown) formed on the peripheral portion of the first transparent film 11, and the drawn wiring is connected to a control IC (not shown). The pattern shape of the transparent conductive layer 12 is any shape, such as a straight strip as shown in FIG. 2 or a diamond shape not shown.

The height (thickness) of the patterned transparent conductive layer 12 is preferably 10 nm to 100 nm, more preferably 10 nm to 50 nm, as in the unpatterned transparent conductive layer 12A. The patterned transparent conductive layer 12 is exemplified by indium tin oxide (ITO: Indium Tin Oxide), indium zinc oxide or indium oxide-oxygen. Formed by the zinc composite oxide, and the unpatterned transparent conductive layer 12A is formed on the first transparent film 11 by, for example, sputtering or vacuum evaporation, and a desired pattern of photoresist is formed on the surface of the transparent conductive layer. It is then carried out using, for example, a wet etching method. When a portion of the transparent conductive layer 12 is removed by wet etching for patterning, a portion of the transparent conductive layer 12 (pattern forming portion) is covered with a mask for pattern formation, and the transparent conductive layer is not covered by the mask. The portion is exposed to the etchant thereby removed. As described above, since the transparent conductive layer 12 uses a conductive metal oxide such as ITO or ATO, the etchant can be applied with an acid. The acid may, for example, be an inorganic acid such as hydrogen chloride, hydrogen bromide, sulfuric acid, nitric acid or phosphoric acid, an organic acid such as acetic acid or the like, or a mixture thereof, or the like.

Further, the transparent conductive film of the present invention can be subjected to heat treatment to crystallize the first and/or second transparent conductor layers. The crystallization of the transparent conductive layer can be performed either before or after patterning the transparent conductive layer. Further, when the transparent conductive layer is patterned by the wet etching method, if the transparent conductive layer is crystallized before the etching, it may be difficult to etch. Therefore, the crystallization of the transparent conductive layer is preferably performed after patterning the transparent conductive layer.

[heat treatment]

After the transparent conductive layer is patterned as described above, the transparent conductive film is supplied to the heat treatment step. The heat treatment may be, for example, heating of the etchant used for patterning after washing with water or the like, heating for drying the cleaning liquid, and heating for crystallizing the amorphous transparent conductor layer. Forming a transparent conductor layer for patterning and electrically connecting to a control mechanism of an IC or the like In the case of pattern wiring, heating for drying silver paste or the like; and heating for assembling and processing the touch panel. Although the possibility of corrugation of the transparent conductive film may be improved by the above heat treatment, in the present invention, the film shrinkage (MD) of the second transparent film and the film shrinkage direction (TD) are thermally contracted. (140 ° C, 90 minutes) are below 0.4%, which can effectively prevent the occurrence of ripples.

[Production method]

An example of a method of producing the transparent conductive film 10 of the present invention will be described. First, the unpatterned transparent conductive layer 12A is formed on one surface of the first transparent film 11 having a thickness of 15 μm to 75 μm by sputtering. Then, on the surface of the first transparent film 11 opposite to the transparent conductive layer 12A, an ultraviolet curable adhesive is applied to a thickness of 0.01 μm or more and less than 10 μm, and the second transparent film 14 is bonded. The thickness of the second transparent film 14 is preferably thicker than the thickness of the first transparent film 11. Next, ultraviolet rays are irradiated from the side of the second transparent film 14 to cure the ultraviolet curable adhesive. Next, a photoresist of the desired pattern is formed on the surface of the unpatterned transparent conductive layer 12A. Then, the unpatterned transparent conductive layer 12A is immersed in hydrochloric acid to remove the unnecessary transparent conductor, thereby obtaining the desired transparent conductive layer 12 which has been patterned.

According to the method for producing the transparent conductive film 10 of the present invention, since the transparent conductive layer is formed into a film, the substrate has only a thin first transparent film 11, and the amount of volatile components derived from the substrate is small. Therefore, the surface resistance value of the transparent conductor layer is reduced and the defect rate is also lowered. Further, when the transparent conductive pattern 12 is formed, the second transparent film 14 having a relatively large thickness and a low heat shrinkage ratio is formed, and the shrinkage resistance is improved, and generation of ripples in the transparent conductive film 10 can be suppressed.

[Examples]

In the following, the present invention will be described in detail by way of examples, but the invention is not to be construed as limited. Further, in each of the examples, the parts and % are based on the weight.

(Modulation of active energy ray-curable adhesive composition)

30 parts of hydroxyethyl acrylamide (manufactured by Xingren Co., Ltd.), 30 parts of methyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), and tripropylene glycol diacrylate (trade name: ARONIX M-220, manufactured by Toagosei Co., Ltd.) 40 parts And 2-methyl-1-(4-methylthiophenyl)-2- 1.5 parts of morphyl propan-1-one (trade name: IRGACURE 907, manufactured by BASF Corporation) was mixed, and the mixture was stirred at 50 ° C for 1 hour to obtain an active energy ray-curable adhesive composition.

[Example 1]

Using a sputtering device equipped with an indium tin oxide sintered body target of 97% by weight of indium oxide and 3% by weight of tin oxide, in a polyethylene terephthalate film (first transparent film: 140 ° C, 90 minutes TD) An indium tin oxide (ITO: Indium Tin Oxide) layer was formed on one surface of a heat shrinkage ratio of 0.35% and a MD heat shrinkage rate of 0.25%. The thickness of the polyethylene terephthalate film was 25 μm, and the thickness of the indium tin oxide layer was 22 nm.

Next, an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cavity shape: honeycomb shape, number of gravure rolls: 1000 pieces/inch, rotation speed: 140%/pair line speed) was used so that the thickness after hardening became 1 μm. The active energy ray-curable adhesive composition is applied to the opposite side of the indium tin oxide layer of the polyethylene terephthalate film, and the polyethylene terephthalate film is bonded. 2 transparent film: 140 ° C, 90 minutes TD heat shrinkage rate of 0.35%, MD heat shrinkage rate of 0.30%). Irradiation of ultraviolet light from a high-pressure mercury lamp from the side of the second transparent film 365 nm in length, the adhesive is cured to obtain a laminate of a transparent conductive film.

The film thickness was measured using a film thickness meter (Digital Gauge Disc DG-205, manufactured by Peacock Co., Ltd.).

[Examples 2 to 14, Comparative Examples 1, 2]

In addition to changing the thickness of the first transparent film to 140 ° C, 90 minutes of TD heat shrinkage rate and MD heat shrinkage rate, thickness of the second transparent film, 140 ° C, 90 minutes of TD heat shrinkage rate and MD heat shrinkage rate are changed to the table A transparent conductive film was produced in the same manner as in Example 1 except for the one contained in 1. Further, in Examples 7-12, 14 and Comparative Example 2, an adhesive layer using the following adhesive composition as a raw material was further provided instead of the adhesive layer. Further, in Examples 13 and 14, a second transparent conductive layer (ITO layer, thickness: 22 nm) was further provided on the surface of the second transparent film opposite to the transparent curing type adhesive layer or the adhesive layer.

(modulation of the adhesive composition)

[Polymerization of acrylic polymer]

93.5 parts by weight of n-butyl acrylate and a acrylonitrile group were placed in a 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube and a cooler. 4 parts by weight of porphyrin, 2 parts by weight of acrylic acid, 0.5 parts by weight of 4-hydroxybutyl acrylate, 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate. Nitrogen gas was introduced while stirring slowly, and after the nitrogen substitution was sufficiently performed, the liquid temperature in the flask was maintained at around 55 ° C, and polymerization reaction was carried out for 15 hours to prepare an acrylic polymer solution. The weight average molecular weight of the above acrylic polymer was 1.89 million.

(modulation of adhesive)

100 weight of solid component relative to the above acrylic polymer solution a mixture of 0.3 parts by weight of diphenylguanidinium peroxide (1 minute half-life: 130 ° C) blended with a crosslinking agent, and a hexamethylene diisocyanate adduct of trimethylolpropane 0.1 part by weight of an acrylic adhesive solution of an isocyanate type crosslinking agent (Takenate D160N, manufactured by Mitsui Chemicals, Inc.).

Next, the acrylic pressure-sensitive adhesive solution was applied onto one surface of the second transparent film, and dried at 150 ° C for 3 minutes to form an adhesive layer having a thickness of 5 μm after drying, and bonded to the first transparent film.

<Method for measuring ripples>

The laminate of the transparent conductive films obtained in Examples 1 to 14 and Comparative Examples 1 and 2 was heat-treated at 140 ° C for 90 minutes to crystallize the indium tin oxide layer. Next, a photoresist of a desired pattern is formed on the surface of the transparent conductor layer. Next, the transparent conductor layer is immersed in hydrochloric acid to remove the unnecessary transparent conductor layer (etching step). Then, it was dried at 140 ° C for 30 minutes to form a straight strip-shaped transparent electrode pattern. The corrugation (height difference) of the portion having the transparent electrode pattern and the portion having no pattern in the transparent conductive film obtained after the etching step was evaluated.

The corrugation (height difference) was measured using an optical surface profiler (Optical Profilometer NT3000 manufactured by Veeco Instruments).

When the height difference is 1.0 μm or less, it means that the corrugation is prevented and is very good.

10‧‧‧Transparent conductive film

11‧‧‧1st transparent film

12A‧‧‧Unpatterned transparent conductive layer

13‧‧‧Transparent hardening adhesive layer or adhesive layer

14‧‧‧2nd transparent film

Claims (9)

A transparent conductive film comprising: a first transparent film; a first transparent conductive layer formed on one surface of the first transparent film and not patterned; a transparent hardening adhesive layer or an adhesive layer And a second transparent film laminated on a surface of the transparent curing adhesive layer or the adhesive layer on a side opposite to the first transparent film; The heat shrinkage ratio (140 ° C, 90 minutes) of the second transparent film in the film length direction (MD) and the film width direction (TD) was 0.4% or less. The transparent conductive film of claim 1, wherein the first transparent conductive layer is patterned. The transparent conductive film according to claim 1 or 2, wherein the first transparent film has a thickness of 15 μm to 75 μm. The transparent conductive film according to claim 1 or 2, wherein the second transparent film has a thickness of 15 μm to 200 μm. The transparent conductive film according to claim 1 or 2, wherein the second transparent conductive layer is formed on a surface of the second transparent film opposite to the transparent curing adhesive layer or the adhesive layer. The transparent conductive film of claim 1 or 2, wherein the aforementioned transparent hardening The thickness of the type of the adhesive layer or the aforementioned adhesive layer is 0.01 μm or more and less than 50 μm. The transparent conductive film according to claim 1 or 2, wherein the material for forming the first transparent film and the material for forming the second transparent film are any of polyethylene terephthalate, polycycloolefin, and polycarbonate. By. The transparent conductive film according to claim 1 or 2, wherein the material for forming the first transparent conductive layer is indium tin oxide (ITO: Indium Tin Oxide), indium zinc oxide, indium oxide-zinc oxide composite oxide, and poly Any of thiophene, carbon nanotube, aluminum zinc oxide, gallium zinc oxide, fluorine zinc oxide, fluorine indium oxide, antimony tin oxide, fluorine tin oxide, and phosphorus tin oxide. The transparent conductive film of claim 1 or 2, wherein the heat shrinkage ratio measured in a state where the first transparent conductive layer is removed and the heat shrinkage ratio measured in a state before the first transparent conductive layer is removed The difference is less than 0.15%.