JP2015105286A - Adhesive layer for transparent conductive film, transparent conductive film with adhesive layer, and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive layer for a transparent conductive film having high sebum resistance and high white turbidness resistance, capable of suppressing change of a dielectric constant under a humidification condition.SOLUTION: In an adhesive layer for a transparent conductive film, a relative dielectric constant in a frequency of 100 kHz under an environment of 23°C and 55%R.H. is 4 or lower, and a moisture percentage after being stored for 120 hours under an environment of 60°C and 95%R.H. is 1 wt.% or less.

Description

  The present invention relates to a pressure-sensitive adhesive layer for a transparent conductive film, which has high sebum resistance and humid clouding resistance and a small change in dielectric constant under humid conditions.

  In addition, the present invention has a transparent conductive thin film formed of a metal oxide on one surface of a transparent plastic film substrate, and on one surface of a transparent conductive film having a functional layer on the other surface, It has the said adhesive layer for transparent conductive films, It is related with the transparent conductive film with an adhesive layer characterized by the above-mentioned. The pressure-sensitive adhesive layer for a transparent conductive film or the transparent conductive film with a pressure-sensitive adhesive layer of the present invention is suitable for use in the production of input devices such as an optical method, an ultrasonic method, a capacitance method, a resistance film method, etc. Can be used. In particular, it is suitably used for a capacitive touch panel.

  Moreover, the transparent conductive film with an adhesive layer of this invention is used for the transparent electrode in a touch panel etc., after an appropriate processing process is made. In particular, the transparent conductive film with an adhesive layer is suitably used for an electrode substrate of an input device of a capacitive touch panel by patterning a transparent conductive thin film.

  In recent years, an input device using a combination of an image display device such as a mobile phone or a portable music player and a touch panel has become widespread. In particular, capacitive touch panels are rapidly spreading due to their functionality.

  Currently, many transparent conductive films used for touch panels are known in which a transparent conductive thin film such as indium tin oxide (ITO) is laminated on a transparent plastic film substrate or glass. A transparent conductive film is laminated | stacked on another member through an adhesive layer.

  When the transparent conductive film is used for an electrode substrate of a capacitive touch panel, a film obtained by patterning the transparent conductive thin film is used. A transparent conductive film having such a patterned transparent conductive thin film is used by being laminated with an adhesive layer together with other transparent conductive films and the like. These transparent conductive films are suitably used for multi-touch type input devices that can be operated simultaneously with two or more fingers. That is, the capacitive touch panel has a mechanism for sensing when an output signal at the position changes when the touch panel is touched with a finger or the like, and the amount of change in the signal exceeds a certain threshold.

  As described above, the dielectric constant of the member and film constituting the touch panel is an important numerical value because it relates to the response of the touch panel. On the other hand, with the spread of touch panels in recent years, higher performance is required for touch panels, and high performance is also required for transparent conductive films and pressure-sensitive adhesive layers that are constituent members, and thinning is one of them. is there. However, there is a problem that the designed capacitance value changes if the pressure-sensitive adhesive layer is simply thinned. In order to reduce the thickness of the pressure-sensitive adhesive layer without changing the value of the capacitance value, it is required to lower the dielectric constant of the pressure-sensitive adhesive layer. In addition, in order to improve visibility, an air layer of a glass with printing or a film and an optical film or an air layer above a liquid crystal display (LCD) may be filled with an adhesive layer. If the adhesive layer has a high dielectric constant, malfunction may occur. Also from the viewpoint of preventing such malfunction, the adhesive layer is required to have a low dielectric constant. Furthermore, the response speed and sensitivity of the touch panel are expected to be improved by reducing the dielectric constant of the adhesive layer. In addition, there is a problem that the adhesive layer becomes cloudy when a laminate obtained by laminating a transparent conductive film or glass via an adhesive layer is exposed to humidification conditions. It has been.

  Various pressure-sensitive adhesive layers that can suppress humidified cloudiness have been proposed. H. There is known a pressure-sensitive adhesive layer having a moisture content of 0.65% by weight or more after storage for 120 hours in the above environment (for example, see Patent Documents 1 and 2). Moreover, as a pressure-sensitive adhesive capable of realizing a low dielectric constant pressure-sensitive adhesive layer, it is obtained by polymerizing a monomer component containing a specific amount of alkyl (meth) acrylate having a branched alkyl group having 10 to 24 carbon atoms at the terminal of the ester group. A pressure-sensitive adhesive containing the (meth) acrylic polymer obtained is known (for example, see Patent Document 3).

JP 2011-99078 A JP 2012-173354 A JP 2012-246477 A

  In the said patent documents 1, 2, 60 degreeC and 95% R. H. It is intended to suppress humidified white turbidity by using a pressure-sensitive adhesive layer having a high moisture content that is 0.65% by weight or more after storage for 120 hours in the above environment. It was found that by using the pressure-sensitive adhesive layer having a high moisture content, the white turbidity of the pressure-sensitive adhesive layer under humidified conditions was eliminated, but the dielectric constant under the humidified conditions was increased. As described above, when the dielectric constant of the pressure-sensitive adhesive layer changes under humidified conditions, malfunctions may occur or the sensitivity may decrease when a touch panel using the pressure-sensitive adhesive layer is used under humidified conditions.

  In addition, as described in Patent Document 3, the adhesive layer has a low dielectric constant by using a specific amount of alkyl (meth) acrylate having a branched alkyl group having 10 to 24 carbon atoms at the end of the ester group. Although it can be realized, the transparent conductive film having the pressure-sensitive adhesive layer has a problem that the pressure-sensitive adhesive layer becomes cloudy under humidified conditions.

  Moreover, since a touch panel is used in the state which a bare hand always contacts, it is not avoided that the sebum of a hand transfers to a touch panel. The sebum transferred to the touch panel surface gradually moves to the pressure-sensitive adhesive layer inside the touch panel, and the pressure-sensitive adhesive layer swells due to sebum, and sebum resistance is required. However, conventionally, the swelling of the pressure-sensitive adhesive layer due to such sebum has not been sufficiently examined, and in Patent Documents 1 to 3, no investigation has been made about the swelling of the pressure-sensitive adhesive layer due to sebum. there were.

  Therefore, an object of the present invention is to provide a pressure-sensitive adhesive layer for a transparent conductive film, which has high sebum resistance and humid clouding resistance and can suppress a change in dielectric constant under humid conditions.

  Another object of the present invention is to provide a transparent conductive film with a pressure-sensitive adhesive layer having the pressure-sensitive adhesive layer for transparent conductive film, and a touch panel having the transparent conductive film with a pressure-sensitive adhesive layer.

  As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive layer for transparent conductive film, and have completed the present invention.

  That is, the present invention has a 23.degree. H. The relative dielectric constant at a frequency of 100 kHz under the environment is 4 or less, and 60 ° C., 95% R.D. H. It is related with the adhesive layer for transparent conductive films characterized by the moisture content after being preserve | saved for 120 hours in this environment being 1 weight% or less.

  60 ° C., 95% R.D. H. The relative dielectric constant at a frequency of 100 kHz in an environment of 23 ° C. and 55% R.D. H. It is preferable that it is 1.2 times or less of the relative dielectric constant of the environmental frequency of 100 kHz.

  The moisture content is preferably 0.6% by weight or less.

  The pressure-sensitive adhesive layer is preferably formed from a rubber-based pressure-sensitive adhesive composition containing a rubber-based polymer.

  It is preferable that the rubber-based polymer contains a conjugated diene copolymer obtained by copolymerizing a conjugated diene compound and an aromatic vinyl compound.

  In addition, the present invention has a transparent conductive thin film formed of a metal oxide on one surface of a transparent plastic film substrate, and on one surface of a transparent conductive film having a functional layer on the other surface, It has the said adhesive layer for transparent conductive films, It is related with the transparent conductive film with an adhesive layer characterized by the above-mentioned.

  In the said transparent conductive film with an adhesive layer, even if it has the said adhesive layer for transparent conductive films on the transparent conductive thin film of the said transparent conductive film, on the functional layer of the said transparent conductive film The transparent conductive film pressure-sensitive adhesive layer may be provided.

  Furthermore, the present invention relates to a touch panel having at least one transparent conductive film with an adhesive layer.

  The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a 23 ° C., 55% R.D. H. The relative dielectric constant at a frequency of 100 kHz under the environment is 4 or less, and 60 ° C., 95% R.D. H. Since the moisture content after storage for 120 hours in the environment is as low as 1% by weight or less, it is possible to realize a pressure-sensitive adhesive layer having a low dielectric constant and excellent resistance to humid turbidity, and dielectric under humid conditions. The rate change is also small, and malfunction of a touch panel using the pressure-sensitive adhesive layer can be prevented.

(A) It is a schematic sectional drawing which shows an example of the transparent conductive film with an adhesive layer to which the adhesive layer for transparent conductive films of this invention was applied. (B) It is a schematic sectional drawing which shows an example of the transparent conductive film with an adhesive layer to which the adhesive layer for transparent conductive films of this invention is applied. It is a figure which shows an example of the capacitive touch panel with which the adhesive layer for transparent conductive films of this invention is applied in relation to a transparent conductive film. It is a schematic sectional drawing of the test piece used by each test of humidification cloudiness resistance.

  The pressure-sensitive adhesive layer for a transparent conductive film of the present invention will be described below with reference to the drawings in the embodiment of the transparent conductive film with a pressure-sensitive adhesive layer.

  FIGS. 1A and 1B are cross-sectional views showing an embodiment in which the transparent conductive film pressure-sensitive adhesive layer 1 of the present invention is provided on a transparent conductive film 2. A transparent conductive film 2 shown in FIG. 1A has a transparent conductive thin film 3 on one surface of a transparent plastic film substrate 4 and a functional layer 5 on the other surface. The adhesive layer 1 for transparent conductive film can be formed on the side having the functional layer 5 of the transparent plastic film substrate 4 (that is, the side opposite to the transparent conductive thin film 3). Moreover, you may protect the adhesive surface of the side by which the transparent conductive film 2 of the adhesive layer 1 for transparent conductive films is not bonded together with a release film (not shown) until it is used practically. Moreover, the transparent conductive film 2 shown in FIG.1 (b) reverses the bonding position of the transparent conductive thin film 3 and the functional layer 5 of Fig.1 (a).

  Although it does not restrict | limit especially as said transparent plastic film base material, The various plastic film which has transparency is used. The plastic film is formed of a single layer film. For example, the materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins. , Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, and the like. Of these, polyester resins, polyimide resins, and polyethersulfone resins are particularly preferable. The thickness of the film substrate is preferably 15 to 200 μm.

  The surface of the film substrate is subjected to an etching treatment or undercoating treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, etc. on the surface in advance, and a transparent conductive thin film or undercoat provided thereon. You may make it improve the adhesiveness with respect to the said film base material of a coating layer. In addition, before providing the transparent conductive thin film or the undercoat layer, dust may be removed and cleaned by solvent cleaning or ultrasonic cleaning as necessary.

  The constituent material of the transparent conductive thin film is not particularly limited, and is selected from the group consisting of indium, tin, zinc, gallium, antimony, titanium, silicon, zirconium, magnesium, aluminum, gold, silver, copper, palladium, tungsten, cadmium. A metal oxide of at least one selected metal is used. The metal oxide may further contain a metal atom shown in the above group, if necessary. For example, although not particularly limited, ITO (indium tin oxide), ZnO, SnO, CTO (cadmium tin oxide) and the like are preferably used, and ITO is particularly preferably used. As ITO, it is preferable to contain 80 to 99 weight% of indium oxide and 1 to 20 weight% of tin oxide. Although the thickness of a transparent conductive thin film is not specifically limited, It is about 10-200 nm, From the viewpoint of a thin film, it is more preferable that it is 15-40 nm, and it is more preferable that it is 20-30 nm.

  In addition, although not shown in FIG. 1, a transparent conductive thin film can be provided in a transparent plastic film base material through an undercoat layer. A plurality of undercoat layers can be provided. An oligomer migration preventing layer can be provided between the transparent plastic film substrate and the pressure-sensitive adhesive layer.

The undercoat layer can be formed of an inorganic material, an organic material, or a mixture of an inorganic material and an organic material. For example, NaF (1.3), Na ₃ AlF ₆ (1.35), LiF (1.36), MgF ₂ (1.38), CaF ₂ (1.4), BaF ₂ (1. 3), inorganic substances such as SiO ₂ (1.46), LaF ₃ (1.55), CeF ₃ (1.63), Al ₂ O ₃ (1.63) Is the refractive index of light. Of these, SiO ₂ , MgF ₂ , A1 ₂ O _{3 and the} like are preferably used. In particular, SiO ₂ is suitable. In addition to the above, a composite oxide containing about 10 to 40 parts by weight of cerium oxide and about 0 to 20 parts by weight of tin oxide with respect to indium oxide can be used.

  Examples of organic substances include acrylic resins, urethane resins, melamine resins, alkyd resins, siloxane polymers, and organic silane condensates. At least one kind of these organic substances is used. In particular, as the organic substance, it is desirable to use a thermosetting resin made of a mixture of a melamine resin, an alkyd resin, and an organosilane condensate.

  The thickness of the undercoat layer is not particularly limited, but is usually about 300 nm or less and about 1 to 300 nm from the viewpoint of optical design and the effect of preventing oligomer generation from the film substrate. Preferably, it is about 5 to 300 nm.

  As the functional layer, for example, an antiglare treatment (AG) layer or an antireflection (AR) layer for the purpose of improving visibility can be provided. The constituent material of the antiglare layer is not particularly limited, and for example, an ionizing radiation curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the antiglare treatment layer is preferably 0.1 to 30 μm. As the antireflection layer, titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, or the like is used. The antireflection layer can be provided with a plurality of layers.

  Moreover, a hard coat (HC) layer can be provided as a functional layer. As a material for forming the hard coat layer, for example, a cured film made of a curable resin such as a melamine resin, a urethane resin, an alkyd resin, an acrylic resin, or a silicone resin is preferably used. The thickness of the hard coat layer is preferably 0.1 to 30 μm. The thickness is preferably 0.1 μm or more for imparting hardness. Further, the antiglare treatment layer and the antireflection layer can be provided on the hard coat layer.

  The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a 23 ° C., 55% R.D. H. The relative dielectric constant at an environmental frequency of 100 kHz is 4 or less, preferably 3.5 or less, more preferably 3.4 or less, and even more preferably 3.2 or less. When the relative dielectric constant falls within the above range, the touch panel using the pressure-sensitive adhesive layer can obtain good response speed and sensitivity. Further, the pressure-sensitive adhesive layer for transparent conductive film of the present invention is 60 ° C., 95% R.D. H. The relative dielectric constant at a frequency of 100 kHz in the above environment is preferably within the above range.

  The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a temperature of 60 ° C. and 95% R.D. H. The relative dielectric constant at a frequency of 100 kHz in an environment of 23 ° C. and 55% R.D. H. It is preferably 1.2 times or less, more preferably 1.1 times or less of the relative dielectric constant of the frequency 100 kHz in the environment. The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a temperature of 60 ° C. and 95% R.D. H. Environment, 23 ° C., 55% R.V. H. The relative permittivity at a frequency of 100 kHz under the environment is substantially the same, and the change in permittivity under humidified conditions is small. Thereby, malfunctioning, such as a touch panel using the said adhesive layer, can be prevented.

  The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a temperature of 60 ° C. and 95% R.D. H. The moisture content after storage for 120 hours in the above environment is 1.0% by weight or less, preferably 0.8% by weight or less, more preferably 0.6% by weight or less, and More preferably, it is 2% by weight or less. By setting the moisture content within the above range, it is possible to suppress a change in relative dielectric constant under humidified conditions.

  The pressure-sensitive adhesive layer for a transparent conductive film of the present invention has a 23 ° C., 50% R.D. H. The haze value in the environment is preferably 2% or less, more preferably 0 to 1.5%, and still more preferably 0 to 1%. When the haze is in the above range, transparency required when the pressure-sensitive adhesive layer is used for an optical member can be satisfied. Moreover, if a haze value is 2% or less, it can be satisfied as an optical use. If the haze value exceeds 2%, white turbidity occurs, which is not preferable for optical film applications.

  The pressure-sensitive adhesive layer for transparent conductive film of the present invention has a pressure-sensitive adhesive layer (thickness: 100 μm) at 60 ° C. and 95% R.D. H. In an environment of 50 hours, stored at 23 ° C., 50% R.D. H. The haze value immediately after taking out in the environment is preferably less than 5%, more preferably 0% or more and less than 2%. The said range is preferable from a humidified cloudiness-resistant viewpoint.

  The pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer for a transparent conductive film of the present invention is not particularly limited, and is 23 ° C., 55% R.D. H. The relative dielectric constant at a frequency of 100 kHz under the environment is 4 or less, and 60 ° C., 95% R.D. H. However, a rubber-based pressure-sensitive adhesive composition having a rubber-based polymer as a base polymer is preferable, as long as it can form a pressure-sensitive adhesive layer having a moisture content of 1% by weight or less after storage for 120 hours. Can be used.

  Examples of the rubber polymer include a conjugated diene polymer obtained by polymerizing one kind of conjugated diene compound, a conjugated diene copolymer obtained by polymerizing two or more kinds of conjugated diene compounds, and a conjugated diene compound. And a conjugated diene copolymer obtained by copolymerizing an aromatic vinyl compound. Moreover, these hydrogenated materials can also be used suitably.

  The conjugated diene compound is not particularly limited as long as it is a monomer having a polymerizable conjugated diene. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3- Examples include pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene. Among these, 1,3-butadiene, isoprene and the like are preferable from the viewpoint of industrial availability. These may be used alone or in combination of two or more.

  The aromatic vinyl compound used for constituting the diene copolymer is not particularly limited as long as it is a monomer having an aromatic vinyl structure copolymerizable with a conjugated diene compound. For example, styrene, p- Examples include methyl styrene, α-methyl styrene, vinyl ethyl benzene, vinyl xylene, vinyl naphthalene, and diphenyl ethylene. Among these, styrene is preferable from the viewpoint of industrial availability. These may be used alone or in combination of two or more.

  The diene copolymer may be a random copolymer or a block copolymer, and may be a copolymer of a compound other than a conjugated diene compound or an aromatic vinyl compound.

  The conjugated diene copolymer obtained by copolymerizing the conjugated diene compound and the aromatic vinyl compound has a molar ratio of the conjugated diene compound and the aromatic vinyl compound such that the conjugated diene compound / aromatic vinyl compound = It is preferable that it is 10-90 mol% / 90-10 mol%.

  Specific examples of such conjugated diene (co) polymers include butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene copolymer (SBR), and butadiene-isoprene-styrene random copolymer. , Isoprene-styrene random copolymer, styrene-isoprene block copolymer (SIS), butadiene-styrene copolymer, styrene-ethylene-butadiene block copolymer (SEBS), acrylonitrile-butadiene rubber (NBR), and the like. These can be used alone or in combination of two or more. Among these, isoprene-styrene copolymers are preferable. Moreover, these hydrogenated materials can also be used suitably.

  In addition to the conjugated diene (co) polymer, isobutylene (IB) or the like can also be used. The rubber-based polymer may be used alone or in combination of two or more.

  The rubber polymer used in the present invention preferably contains the conjugated diene (co) polymer as a base polymer, and the rubber polymer as a whole contains 50% by weight or more of the conjugated diene (co) polymer. Preferably, it is contained 70% by weight or more, more preferably 80% by weight or more, and more preferably 90% by weight or more. The upper limit is not particularly limited, and may be 100% by weight (that is, a rubber-based polymer composed only of a conjugated diene (co) polymer).

  The pressure-sensitive adhesive composition contains the rubber-based polymer as a base polymer, and the addition amount of the rubber-based polymer is preferably 40% by weight or more, and 50% by weight or more in the pressure-sensitive adhesive composition. More preferably, it is more preferably 60% by weight or more. Moreover, although it does not specifically limit as an upper limit, It is preferable that it is 90 weight% or less in an adhesive composition.

  In addition to the rubber polymer, the pressure-sensitive adhesive composition includes a crosslinking agent (eg, polyisocyanate, alkyl etherified melamine compound), a tackifier (eg, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble). (Phenol resin, vinyl toluene resin, etc.), plasticizers, fillers, anti-aging agents, and other suitable additives may be included. These addition amounts are preferably 60% by weight or less, more preferably 50% by weight or less, and still more preferably 40% by weight or less in the pressure-sensitive adhesive composition.

  The thickness of the pressure-sensitive adhesive layer for transparent conductive film of the present invention is not particularly limited. For example, the thickness is preferably about 1 to 300 μm, more preferably 1 to 200 μm, and 2 to 100 μm. More preferably, it is more preferably 25-100 μm.

  The pressure-sensitive adhesive layer can be formed as a pressure-sensitive adhesive sheet by, for example, applying the pressure-sensitive adhesive to a support and drying and removing the solvent. In applying the pressure-sensitive adhesive, one or more solvents may be appropriately added.

  Various methods are used as a method of applying the adhesive. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  The heating and drying temperature is preferably about 30 ° C to 200 ° C, more preferably 40 ° C to 180 ° C, and further preferably 80 ° C to 150 ° C. By setting the heating temperature in the above range, an adhesive layer having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

  As the support, for example, a release-treated sheet can be used. A silicone release liner is preferably used as the release-treated sheet.

  When the pressure-sensitive adhesive layer is exposed on the release-treated sheet, the pressure-sensitive adhesive layer may be protected with a release-treated sheet (separator) until practical use. . In practical use, the peeled sheet is peeled off.

  As a constituent material of the separator, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and a polyester film, a porous material such as paper, cloth, and nonwoven fabric, a net, a foamed sheet, a metal foil, and a laminate thereof, as appropriate. Although a thin leaf body etc. can be mentioned, a plastic film is used suitably from the point which is excellent in surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. For the separator, silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, release by silica powder, and antifouling treatment, coating type, kneading type, vapor deposition, as required An antistatic treatment such as a mold can also be performed. In particular, when the surface of the separator is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the pressure-sensitive adhesive layer can be further improved.

  The pressure-sensitive adhesive layer for a transparent conductive film of the present invention is applied to the functional layer or the transparent conductive layer of the transparent conductive film and used as a transparent conductive film with a pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive layer can be directly formed on the functional layer or the transparent conductive layer of the transparent conductive film, and the pressure-sensitive adhesive layer can be formed on the transparent conductive film by removing the solvent by heat drying or the like. Moreover, the adhesive layer formed in the separator which carried out the peeling process can be appropriately transcribe | transferred to the functional layer or transparent conductive layer of a transparent conductive film, and a transparent conductive film with an adhesive layer can be formed.

  In addition, the sheet | seat which carried out the peeling process used in preparation of said transparent conductive film with an adhesive layer can be used as a separator of a transparent conductive film with an adhesive layer as it is, and can simplify in the surface of a process.

  In the transparent conductive film with the pressure-sensitive adhesive layer, when forming the pressure-sensitive adhesive layer, an anchor layer is formed on the surface of the transparent conductive film, or various easy adhesion treatments such as corona treatment and plasma treatment are performed. After that, the pressure-sensitive adhesive layer can be formed. Moreover, you may perform an easily bonding process on the surface of an adhesive layer.

  The said transparent conductive film with an adhesive layer is used in formation of various apparatuses, such as a touch panel and a liquid crystal display. In particular, it can be preferably used as an electrode plate for a touch panel. The touch panel is suitably used for various detection methods (for example, a resistance film method, a capacitance method, etc.).

  In a capacitive touch panel, a transparent conductive film provided with a transparent conductive thin film having a predetermined pattern shape is usually formed on the entire surface of the display unit.

  An example of a capacitive touch panel in which the transparent conductive film with an adhesive layer of the present invention is used is shown in FIG. In FIG. 2, 6 is a capacitive touch panel, 7 is a decorative panel, 8 is an adhesive layer or an adhesive sheet, 9 is a transparent conductive film, and 10 is a hard coat film. The decorative panel 7 is preferably a glass plate or a transparent acrylic plate (PMMA plate). The hard coat film 10 is preferably one obtained by subjecting a transparent plastic film such as a PET film to a hard coat treatment.

  For example, in FIG. 2, the pressure-sensitive adhesive layer 8 sandwiched between two transparent conductive films 9 corresponds to the pressure-sensitive adhesive layer 1 for transparent conductive film of the present invention shown in FIG.

  The capacitive touch panel 6 uses the transparent conductive film pressure-sensitive adhesive layer 1 of the present invention, and therefore has high sebum resistance and humid clouding resistance, and can be reduced in thickness and operated. Excellent stability. Also, the appearance and visibility are good.

  Moreover, the adhesive layer for transparent conductive films of this invention can be used also in touch panels other than the said structure. Specifically, transparent substrate (for example, glass) / adhesive layer (or adhesive sheet) / transparent conductive film / adhesive layer (or adhesive sheet) / transparent conductive film / adhesive layer (or adhesive sheet) / Liquid crystal display (LCD); Transparent substrate with transparent conductive thin film such as ITO (for example, glass) / Adhesive layer (or adhesive sheet) / Transparent conductive film / Adhesive layer (or adhesive sheet) / Liquid crystal It can be applied in the configuration of a display device (LCD).

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight. Evaluation items in Examples and the like were measured as follows.

Example 1
Release surface of polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) having a thickness of 38 μm, with one side of the isoprene rubber adhesive (SK Dyne 2563, manufactured by Soken Chemical Co., Ltd.) peeled off with silicone. Then, a coating layer was formed by coating so that the final thickness was 100 μm. Subsequently, the coating layer was dried at 85 ° C. for 5 minutes to form a rubber-based pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet was produced. Further, the pressure-sensitive adhesive sheet has a 38 μm-thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) obtained by peeling the one side with silicone, and the pressure-sensitive adhesive layer is in contact with the peeling-treated surface. Were pasted together. The polyester film coated on both sides of the pressure-sensitive adhesive layer functions as a release liner.

Comparative Example 1
(Preparation of acrylic polymer solution)
As monomer components, 63 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinylpyrrolidone (NVP), 9 parts by weight of methyl methacrylate (MMA), 13 parts by weight of hydroxyethyl acrylate (HEA), and polymerization 175 parts by weight of ethyl acetate as a solvent was put into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this way, 0.2 part by weight of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the mixture was heated to 65 ° C. and reacted for 5 hours. Thereafter, the temperature was raised to 70 ° C. and reacted for 2 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer solution having a solid concentration of 30% by weight. In addition, the weight average molecular weight of the acrylic polymer in the acrylic polymer solution was 750,000.

(Preparation of acrylic pressure-sensitive adhesive composition)
Next, 0.25 parts by weight of a crosslinking agent (isocyanate crosslinking agent, trade name: Takenate D110N, manufactured by Mitsui Chemicals, Inc.) is added to 100 parts by weight of the acrylic polymer to the acrylic polymer solution. By mixing, an acrylic pressure-sensitive adhesive composition was obtained.

(Preparation of adhesive sheet)
Next, the thickness of the acrylic pressure-sensitive adhesive composition after drying on the release-treated surface of a polyethylene terephthalate separator (PET separator) (trade name: MRF75, manufactured by Mitsubishi Resin Co., Ltd.) whose surface has been subjected to a release treatment is Apply to 100 μm, heat-dry at 135 ° C. for 2 minutes, and then age at 120 ° C. for 120 hours to form an adhesive sheet (base-less adhesive having an acrylic pressure-sensitive adhesive layer / release film configuration) Sheet).

Comparative Example 2
(Preparation of acrylic polymer solution)
As monomer components, 2-ethylhexyl acrylate (2EHA) 59 parts by weight, N-vinylpyrrolidone (NVP) 10 parts by weight, methyl methacrylate (MMA) 21 parts by weight, hydroxyethyl acrylate (HEA) 10 parts by weight, and polymerization 175 parts by weight of ethyl acetate as a solvent was put into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this way, 0.2 part by weight of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the mixture was heated to 65 ° C. and reacted for 5 hours. Thereafter, the temperature was raised to 70 ° C. and reacted for 2 hours. Thereafter, ethyl acetate was added to obtain an acrylic polymer solution having a solid concentration of 30% by weight. In addition, the weight average molecular weight of the acrylic polymer in the acrylic polymer solution was 900,000.

  A pressure-sensitive adhesive sheet was prepared in the same manner as in Comparative Example 1 except that the above solution was used as the acrylic polymer solution.

Comparative Example 3
(Preparation of acrylic polymer solution)
As monomer components, 61 parts by weight of 2-ethylhexyl acrylate (2EHA), 14 parts by weight of N-vinylpyrrolidone (NVP), 22 parts by weight of 4-hydroxybutyl acrylate (4HBA), 3 parts by weight of hydroxyethyl acrylate (HEA) And 0.05 parts by weight of two types of photopolymerization initiator (trade name: Irgacure 184, manufactured by BASF) and 0.05 part by weight of photopolymerization initiator (trade name: Irgacure 651, manufactured by BASF) The monomer mixture was prepared by charging into a flask. Next, the monomer mixture was partially photopolymerized by exposing it to ultraviolet rays under a nitrogen atmosphere to obtain a partially polymerized product (acrylic polymer syrup) having a polymerization rate of about 10% by weight.

  100 parts by weight of the acrylic polymer syrup described above, 0.035 parts by weight of trimethylolpropane triacrylate (TMPTA), and a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 After adding the parts, they were uniformly mixed to prepare a monomer component.

(Preparation of adhesive sheet)
Next, the monomer component prepared above is peeled on the surface of a 38 μm thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having one surface peeled off with silicone, and the final thickness is 100 μm. It applied so that an application layer might be formed. Next, a 38 μm-thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having one surface peeled with silicone on the surface of the applied monomer component, the peel-treated surface of the film is on the coating layer side It coat | covered so that it might become. Thereby, the coating layer of the monomer component was shielded from oxygen. Using a chemical light lamp (manufactured by Toshiba Corp.), the sheet having the coating layer thus obtained was irradiated with ultraviolet rays having an illuminance of 5 mW / cm ² (measured with Topcon UVR-T1 having a maximum sensitivity of about 350 nm). Irradiated for 2 seconds, the coating layer was cured to form an adhesive layer, and an adhesive sheet was produced. The polyester film coated on both sides of the pressure-sensitive adhesive layer functions as a release liner.

  The following evaluation was performed about the adhesive sheet (sample) obtained by the said Example and comparative example.

<Moisture content>
10 cm ² (5 cm × 2 cm) was cut out from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and placed in a warming and humidifying chamber (60 ° C., 95% RH) for 120 hours with both side separators attached. The separator was removed from the heating and humidification chamber, and the separator was attached to an aluminum foil and weighed (W1 (μg)), and this was used as a test piece. The weight of the aluminum foil was measured in advance (W2 (μg)) before being attached to the adhesive sheet.
Next, the test piece is put into the following heating vaporizer and the gas generated when heated at 150 ° C. is introduced into the titration cell of the following coulometric titration moisture measuring device, and the amount of moisture in the gas (μg ) At 60 ° C. and 95% R.D. H. The water content (W3 (μg)) in the pressure-sensitive adhesive layer after storage for 120 hours in the environment was measured. And according to the following formula, 60 ° C., 95% R.D. H. The moisture content (% by weight) of the pressure-sensitive adhesive layer after storage for 120 hours under the above environment was calculated. The number of measurements (n number) was set to 2 times, and the average value was calculated.

(Analysis equipment)
Coulometric titration moisture measuring device: Mitsubishi Chemical Analytech Co., Ltd., CA-200 type heating vaporizer: Mitsubishi Chemical Analytech Co., Ltd., VA-200 type (measuring conditions)
Method: Heat vaporization method / 150 ° C heating anolyte: Aquamicron AKK
Catholyte: Aquamicron CXU

<Sebum resistance>
(Adjustment of sebum fluid)
41 parts by weight of triglyceride (trade name: Lexol GT-865, manufactured by INOLEX), 16.4 parts by weight of isostearic acid (manufactured by Wako Pure Chemical Industries, Ltd.), 12 parts by weight of squalane (manufactured by Wako Pure Chemical Industries, Ltd.) It mixed uniformly and produced sebum liquid.

(Measurement of sebum swelling degree)
The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into 3 cm × 3 cm, and the PET film on which one silicone treatment was applied was peeled off, and the pressure-sensitive adhesive surface was attached to one surface of a 100 μm PET film with a hand roller. Thereafter, the other PET-treated PET film was peeled off, and the pressure-sensitive adhesive surface was attached to one surface of alkali glass to obtain a test piece (100 μm PET film / pressure-sensitive adhesive layer / alkali glass). The obtained test piece was added to the prepared sebum solution at 50 ° C. and 95% R.D. H. It was immersed for 120 hours under the conditions, and the area (cm ² ) after swelling was measured.

The degree of sebum swelling was evaluated according to the following criteria.
A: Sebum swelling degree is less than 1.1 (very good sebum resistance)
○: Sebum swelling degree is 1.1 or more and less than 1.2 (good sebum resistance)
X: Sebum swelling degree is 1.2 or more (sebum resistance is poor)

<Humidity-resistant cloudiness>
The transparent conductive film (HC (clear hard coat) layer / PET layer (PET base material layer) / ITO layer film) is allowed to stand in a temperature environment of 140 ° C. for 90 minutes to crystallize the ITO layer. It was.

  One of the adhesive-treated PET films subjected to silicone treatment was peeled off and bonded so that the HC layer surface of the transparent conductive film was in contact with the adhesive surface. And from the obtained laminated structure (silicone-treated PET film / adhesive layer / transparent conductive film), the silicone-treated PET film is peeled, and the adhesive surface and glass (trade name: MICRO SLIDE GLASS) , Product number: S-1111, manufactured by Matsunami Glass Co., Ltd.) was used as a test piece. The schematic cross-sectional view of the test piece is composed of ITO layer 11 / PET base material layer 12 / HC layer 13 / adhesive layer 1 / glass 14, as shown in FIG.

  The haze of the test piece was measured at 23 ° C. and 50% R.D. H. The measurement was performed using a haze meter (trade name: HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.). And it confirmed that haze (initial haze) was 2.0% or less.

Subsequently, the test piece was subjected to 60 ° C. and 95% R.D. H. After being stored for 500 hours in an environment (humid heat environment) of 23 ° C., 50% R.C. H. The haze of the test piece immediately after removal was measured in the same manner as described above and evaluated according to the following criteria.
A: Haze of test piece immediately after removal is less than 2.0% (very good)
◯: The haze of the test piece immediately after removal is 2.0% or more and less than 5.0% (good)
X: Haze of test piece immediately after taking out is 5.0% or more (defect)

<Dielectric constant>
A pressure-sensitive adhesive layer (a film obtained by peeling a silicone-treated PET film from a pressure-sensitive adhesive sheet) was sandwiched between a copper foil and an electrode, and a relative dielectric constant at a frequency of 100 kHz was measured by the following apparatus. Three samples were prepared for measurement, and the average of the measured values of these three samples was taken as the dielectric constant. The relative dielectric constant of the pressure-sensitive adhesive layer at a frequency of 100 kHz was measured according to JIS K 6911 under the following conditions.
Measuring method: Capacity method (apparatus: using Agilent Technologies E4980A Precision LCR Meter)
Electrode configuration: 12.1 mmφ, 0.5 mm thick aluminum plate Counter electrode: 3 oz copper plate Measurement environment: 23 ° C., 55% R.D. H.
Measurement environment (humidification conditions): 60 ° C., 95% R.D. H. Next, leave the adhesive on the measuring jig for 30 minutes and measure the dielectric constant after 30 minutes.

DESCRIPTION OF SYMBOLS 1 Adhesive layer for transparent conductive films 2 Transparent conductive film 3 Transparent conductive thin film 4 Transparent plastic film base material 5 Functional layer 6 Capacitive touch panel 7 Decoration panel 8 Adhesive layer for transparent conductive films 9 Transparent conductive Film 10 Hard coat film 11 ITO layer 12 PET substrate layer 13 HC layer 14 Glass

Claims (9)

  23 ° C., 55% R.D. H. The relative dielectric constant at a frequency of 100 kHz under the environment is 4 or less, and 60 ° C., 95% R.D. H. A pressure-sensitive adhesive layer for a transparent conductive film, wherein the moisture content after storage for 120 hours in the environment is 1% by weight or less.   60 ° C., 95% R.D. H. The relative dielectric constant at a frequency of 100 kHz in an environment of 23 ° C. and 55% R.D. H. The pressure-sensitive adhesive layer for a transparent conductive film according to claim 1, wherein the pressure-sensitive adhesive layer has a relative dielectric constant of 1.2 times or less of an environmental frequency of 100 kHz.   The said moisture content is 0.6 weight% or less, The adhesive layer for transparent conductive films of Claim 1 or 2 characterized by the above-mentioned.   The said adhesive layer is formed from the rubber-type adhesive composition containing a rubber-type polymer, The adhesive layer for transparent conductive films in any one of Claims 1-3 characterized by the above-mentioned.   The pressure-sensitive adhesive layer for a transparent conductive film according to claim 4, wherein the rubber polymer contains a conjugated diene copolymer obtained by copolymerizing a conjugated diene compound and an aromatic vinyl compound. .   The transparent plastic film substrate has a transparent conductive thin film formed of a metal oxide on one side and a functional layer on the other side, on one side of the transparent conductive film. A transparent conductive film with a pressure-sensitive adhesive layer, comprising the pressure-sensitive adhesive layer for a transparent conductive film according to any one of the above.   The transparent conductive film with a pressure-sensitive adhesive layer according to claim 6, comprising the pressure-sensitive adhesive layer for the transparent conductive film on a transparent conductive thin film of the transparent conductive film.   The transparent conductive film with a pressure-sensitive adhesive layer according to claim 6, wherein the pressure-sensitive adhesive layer for the transparent conductive film is provided on a functional layer of the transparent conductive film.   It has at least 1 the transparent conductive film with an adhesive layer in any one of Claims 6-8, The touch panel characterized by the above-mentioned.

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