JP6715060B2 - Substrate for transparent conductive film, substrate for touch panel, and transparent adhesive substrate for transparent conductive film - Google Patents

Description

The present invention relates to a transparent conductive film substrate, a touch panel substrate, and a transparent adhesive substrate for a transparent conductive film.

2. Description of the Related Art In recent years, liquid crystal display devices have been mounted as image display elements in electronic equipment terminals such as portable electronic organizers and information terminals. As an input device of a liquid crystal display device, a touch panel which is a position input device is often mounted on a liquid crystal display element.

As a touch panel of this type, various methods such as a resistance film method, an electrostatic capacity method, an optical method, and an ultrasonic method are generally known due to the difference in the touch position detection principle. The resistance film method detects the input position based on the difference in the resistance value at the time of energization according to the touch position due to mechanical pressure contact, and can be manufactured relatively inexpensively. On the other hand, the electrostatic capacitance method detects the input position based on the difference in electrostatic capacitance depending on the touch position. Mainly, the surface capacitive (Surface Capacitive) method and the projection electrostatic method are used. The capacity (Projected Capacitive) method is known.

When manufacturing these touch panels, a transparent hard coat film (a substrate for transparent conductive film) including a transparent substrate such as a PET substrate and a hard coat layer provided on at least one surface of the transparent substrate is generally used. (See Patent Documents 1 and 2). This substrate for transparent conductive film is transparent by providing a transparent conductive film such as an indium tin oxide (hereinafter, also referred to as “ITO”) thin film, a silver nanowire thin film, or a grid-like metal thin film on one surface thereof. It is a conductive hard coat film (touch panel substrate). When mounting the touch panel, the touch panel substrate is attached to a cover glass or a plastic substrate via an adhesive or the like.

JP, 2010-191969, A JP, 2005-063058, A

In recent years, thinning of liquid crystal display devices has been further advanced, and thinning of various members used in the liquid crystal display device has been strongly demanded. Against this background, adoption of a thin transparent substrate is being considered for thinning the substrate for a transparent conductive film.

However, if the transparent base material of the transparent conductive film substrate is simply thinned, the rigidity of the transparent base material becomes weak, which causes various manufacturing problems. For example, thermal contraction of the functional layer during coating and formation of the functional layer such as a hard coat layer, or heat applied during formation of the transparent conductive film easily causes thermal deformation of the transparent substrate, resulting in a flat surface of the laminate. Property or surface smoothness is impaired. Therefore, transparent base material, transparent conductive film, various functional layers (hard coat layer, anti-fingerprint layer, antifouling layer, anti-blocking layer, anti-glare layer, anti-reflection layer, ultraviolet absorbing layer, Newton's ring suppressing layer, and index matching) It becomes difficult to align the layers, etc.), and wrinkles are likely to occur during bonding, for example. Further, when storing or transporting the substrate for transparent conductive film or the substrate for touch panel described above, when an easily peelable protective film (separator layer) is provided on the outermost surface of these from the viewpoint of surface protection or the like, the outer peripheral edge of the separator layer There is also a problem that unintended partial peeling occurs in the part.

The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a substrate for a transparent conductive film and a substrate for a touch panel using the same, which has a good handleability even if the transparent substrate is made into a thin film, and enables precise lamination of each layer. .. Another object of the present invention is to provide a transparent pressure-sensitive adhesive substrate that is particularly useful for producing the above-mentioned substrate for transparent conductive film and substrate for touch panel.

The inventors diligently studied to solve the above problems. As a result, in a transparent conductive film substrate provided with a transparent substrate, at least one surface side of the transparent substrate, by providing a predetermined pressure-sensitive adhesive layer and a separator layer, found that the above problems can be solved, The invention was reached.

That is, the present invention provides the specific embodiments shown in the following (1) to (7).
(1) A substrate for a transparent conductive film comprising a transparent base material, wherein an adhesive layer and a separator layer are provided in this order on one surface side of the transparent base material, and the separator layer for the adhesive layer. The substrate for transparent conductive film is characterized in that the 15 degree peeling force at 23° C. and 50% RH is 2.00 N/25 mm width or more (peeling speed 50 mm/min).
(2) At least one functional layer selected from the group consisting of a hard coat layer, a fingerprint adhesion preventing layer, an antifouling layer, an antiblocking layer, an antiglare layer, an antireflection layer, a Newton's ring suppressing layer, and an index matching layer. The substrate for transparent conductive film as described in (1) above, further comprising:
(3) The substrate for transparent conductive film as described in (1) or (2) above, wherein the transparent substrate has a thickness of 10 to 150 μm.
(4) Any of (1) to (3) above, wherein the separator layer has a 90 degree peel force at 23° C. and 50% RH with respect to the pressure-sensitive adhesive layer of 0.05 N/25 mm width or more at a peel speed of 150 mm/min. The substrate for transparent conductive film as described in 1 above.

(5) A substrate for a touch panel including a transparent conductive film and a transparent base material, wherein an adhesive layer and a separator layer are provided in this order on one surface side of the transparent base material, and the other side of the transparent base material is provided. The transparent conductive film is provided on the surface side of the separator layer, and the 15-degree peeling force of the separator layer with respect to the pressure-sensitive adhesive layer at 23° C. and 50% RH is 2.00 N/25 mm width or more (peeling speed 50 mm/min). A substrate for a touch panel, which is
(6) At least one selected from the group consisting of a hard coat layer, a fingerprint adhesion preventing layer, an antifouling layer, an antiblocking layer, an antiglare layer, an antireflection layer, an ultraviolet absorbing layer, a Newton's ring suppressing layer, and an index matching layer. And the functional layer and the transparent conductive film are provided in this order on the other surface side of the transparent substrate, and the touch panel substrate according to (5) above.
(7) A transparent pressure-sensitive adhesive base material for a transparent conductive film, comprising: a pressure-sensitive adhesive layer; and a separator layer provided on one surface side and the other surface side of the pressure-sensitive adhesive layer, wherein For a transparent conductive film, the separator layer provided on one surface side has a 15 degree peeling force at 23° C. and 50% RH of 2.00 N/25 mm width or more (peeling speed 50 mm/min). Transparent adhesive base material.

In the substrate for transparent conductive film and the substrate for touch panel of the present invention, since the pressure-sensitive adhesive layer and the separator layer are provided on one surface side of the transparent base material, these pressure-sensitive adhesive layer and separator layer reinforce the transparent base material. Acts as a layer. Therefore, the weakness of the waist due to the thinning of the transparent substrate is mitigated, and the influence of heat at the time of coating and forming various functional layers and the formation of the transparent conductive film is mitigated. Moreover, since the separator layer can be peeled off and attached as it is when the touch panel is mounted, it is possible to reduce the number of steps, and it is possible to promote thinning of the transparent substrate by the thickness of the separator layer. .. Furthermore, by further setting the 15-degree peeling force of the separator layer to the adhesive layer to be 2.00 N/25 mm width or more (peeling speed 50 mm/min), unintentional partial peeling at the outer peripheral edge portion of the separator layer is reduced. It It is presumed that as a result of the combination of these, even if the transparent substrate is made into a thin film, the handleability is not excessively impaired, and precise layer formation of each layer is facilitated. However, the action is not limited to these.

According to the present invention, it is possible to provide a substrate for a transparent conductive film and a substrate for a touch panel using the same, which is easy to handle even if the transparent substrate is made into a thin film, and allows precise layered formation of each layer. Further, it is possible to provide a transparent pressure-sensitive adhesive base material which is particularly useful for producing the above-mentioned substrate for transparent conductive film and substrate for touch panel.

It is a schematic cross section which shows the principal part of the board|substrate for transparent conductive films of one Embodiment. It is a schematic cross section which shows the principal part of the board|substrate for touch panels of one Embodiment. It is a schematic cross section which shows the principal part of the transparent adhesive base material of one Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the positional relationship such as top, bottom, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. However, the following embodiments are exemplifications for explaining the present invention, and the present invention is not limited to these, and can be arbitrarily modified and carried out without departing from the scope of the invention. .. In the present specification, for example, the notation of a numerical range such as “1 to 100” includes both the lower limit value “1” and the upper limit value “100”. The same applies to other numerical ranges.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a main part of the transparent conductive film substrate 101 of the present embodiment. The transparent conductive film substrate 101 includes a transparent base material 11, a functional layer 21 provided on the one surface 11a side of the transparent base material 11, and an adhesive provided on the other surface 11b side of the transparent base material 11. It has a layer 31 and a separator layer 41. Hereinafter, each component of the transparent conductive film substrate 101 will be described in detail.

[Transparent substrate]
The type of the transparent substrate 11 is not particularly limited as long as it can support the functional layer 21. Specific examples thereof include a glass substrate and a synthetic resin film. From the viewpoint of dimensional stability, mechanical strength, weight reduction, etc., a synthetic resin film is preferably used. The synthetic resin film is formed from polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, cyclic olefin polymer, polystyrene, triacetyl cellulose, (meth)acrylic acid ester, polyvinyl chloride, fluorine resin, etc. The film which was made is mentioned. Among these, as the transparent substrate 11, a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate is preferable. Above all, a stretched film, particularly a biaxially stretched polyester film is particularly preferable because it has excellent mechanical strength and dimensional stability.

The transparency of the transparent substrate 11 is not particularly limited as long as it is optically transparent, but the total light transmittance is preferably 85% or more, more preferably 88% or more, and further preferably 90% or more. If necessary, the transparent substrate 11 may be subjected to plasma treatment, corona discharge treatment, far ultraviolet ray irradiation treatment, anchor treatment, or the like. Further, the transparent substrate 11 may contain an ultraviolet absorber or a light stabilizer.

The thickness of the transparent substrate 11 can be appropriately set according to the required performance and the application and is not particularly limited. Generally, it is 10 to 150 μm, preferably 20 to 125 μm, and more preferably 23 to 80 μm. By using the transparent substrate 11 having a thickness of 80 μm or less, the thinning effect becomes particularly remarkable as compared with the conventional case.

[Functional layer]
Next, the functional layer 21 will be described. The functional layer 21 is a layer provided in order to enhance the function of the transparent conductive film substrate 101, for example, to improve surface smoothness, surface hardness, scratch resistance, antifouling property, optical characteristics, and the like. .. As the functional layer 21, a transparent conductive film or any layer known in the touch panel industry can be used. Specific examples include a hard coat layer, a fingerprint adhesion preventing layer, an antifouling layer, an antiblocking layer, an antiglare layer, an antireflection layer, an ultraviolet absorbing layer, a Newton's ring suppressing layer, an index matching layer, and the like. Not limited. Further, the functional layer 21 may be a single layer having any one of these functions or a single layer in which a plurality of these functions are combined, and a plurality of layers are laminated. It may be a complex.

In this embodiment, a hard coat layer is provided as the functional layer 21. The hard coat layer is a coating film provided to increase the surface hardness of the transparent substrate 11 and prevent the surface from being scratched. Further, it may be provided for the purpose of enhancing the surface smoothness of the transparent substrate 11.

As the hard coat layer, a known one can be used, and generally, it is composed of a thin film of a thermoplastic resin, a thermosetting resin, an ionizing radiation curable resin or the like. In this embodiment, the hard coat layer is provided only on one surface 11a of the transparent substrate 11, but both the one surface 11a side and the other surface 11b side of the transparent substrate 11 are illustrated. It is also possible to provide a hard coat layer.

As the thermoplastic resin and the thermosetting resin, saturated or unsaturated polyester resin, acrylic resin, acrylic urethane resin, polyester acrylate resin, polyurethane acrylate resin, epoxy acrylate resin, urethane resin, epoxy resin Resin, vinyl resin, polycarbonate resin, cellulose resin, acetal resin, polyethylene resin, polystyrene resin, polyamide resin, polyimide resin, melamine resin, phenol resin, silicone resin, etc. However, it is not particularly limited to these. These may be used alone or in combination of two or more.

As the ionizing radiation curable resin, a photopolymerizable prepolymer which is cured by irradiation with ionizing radiation (ultraviolet ray or electron beam) can be used. Further, the photopolymerizable prepolymer can be used alone, but it is preferable to use a photopolymerizable monomer in combination from the viewpoint of imparting or improving various properties such as improvement of crosslinking curability and adjustment of curing shrinkage. Further, if necessary, an auxiliary agent such as a photopolymerization initiator, a photopolymerization accelerator, a sensitizer (for example, an ultraviolet sensitizer) may be used.

The photopolymerizable prepolymer is generally classified into a cationic polymerization type and a radical polymerization type. Examples of the cationic polymerization type photopolymerizable prepolymer include epoxy resins and vinyl ether resins. Examples of the epoxy resin include bisphenol epoxy resin, novolac type epoxy resin, alicyclic epoxy resin, and aliphatic epoxy resin. Examples of the radical polymerization type photopolymerizable prepolymer include acrylic prepolymers (hard prepolymers). The photopolymerizable prepolymers may be used alone or in combination of two or more. Among these, an acrylic prepolymer (hard prepolymer) having two or more acryloyl groups in one molecule and having a three-dimensional network structure by crosslinking and curing is preferable from the viewpoint of hard coat property.

Examples of the acrylic prepolymer include, but are not particularly limited to, urethane acrylate, polyester acrylate, epoxy acrylate, melamine acrylate, polyfluoroalkyl acrylate, and silicone acrylate. The acrylic prepolymers may be used alone or in combination of two or more.

Examples of the urethane acrylate prepolymer include, but are not limited to, those obtained by esterifying a polyurethane oligomer obtained by the reaction of a polyether polyol or polyester polyol with a polyisocyanate by a reaction with (meth)acrylic acid. The urethane acrylate prepolymer can be used alone or in combination of two or more.

As the polyester acrylate prepolymer, a polyester oligomer having a hydroxyl group at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol is esterified with (meth)acrylic acid, and a polyvalent carboxylic acid is an alkylene oxide. Examples thereof include those obtained by esterifying the hydroxyl group at the terminal of the oligomer obtained by adding (meth)acrylic acid, but are not particularly limited thereto. The polyester acrylate prepolymer may be used alone or in combination of two or more.

Examples of the epoxy acrylate prepolymer include, but are not particularly limited to, those obtained by esterification of a bisphenol-type epoxy resin or novolac epoxy resin having a relatively low molecular weight with a (meth)acrylic acid and an oxirane ring. The epoxy acrylate prepolymer can be used alone or in combination of two or more.

As the photopolymerizable monomer, a monofunctional acrylic monomer (for example, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, butoxyethyl acrylate, etc.), a bifunctional acrylic monomer (for example, 1,6-hexanediol diacrylate) , Neopentyl glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, hydroxypivalate neopentyl glycol diacrylate, etc.) trifunctional or higher functional acrylic monomers (eg, dipentaerythritol hexaacrylate, trimethylpropane triacrylate, pentaerythritol triacrylate) Acrylate etc.), etc., but not particularly limited thereto. These photopolymerizable monomers may be used alone or in combination of two or more. In addition, in this specification, "acrylate" is a concept including not only literal acrylate but also methacrylate.

As the photopolymerization initiator, for radical polymerization type photopolymerizable prepolymers and photopolymerizable monomers, for example, acetophenone, benzophenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoyl benzoate, hydroxycyclohexyl phenyl ketone, 2-methyl- Examples thereof include 1-(4-(methylthio)phenyl)-2-(4-morpholinyl)-1-propane, α-acyl oxime ester, and thioxanthones, but are not particularly limited thereto. As the photopolymerization initiator for the cationic polymerization type photopolymerizable prepolymer, for example, aromatic sulfonium ions, aromatic oxosulfonium ions, onium such as aromatic iodonium ions, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, Examples of the compound include an anion such as hexafluoroarsenate, but are not particularly limited thereto. These may be used alone or in combination of two or more.

Examples of the photopolymerization accelerator include p-dimethylaminobenzoic acid isoamyl ester and p-dimethylaminobenzoic acid ethyl ester. Examples of the UV sensitizer include, but are not limited to, n-butylamine, triethylamine, tri-n-butylphosphine and the like. These may be used alone or in combination of two or more.

The amount of these auxiliaries to be blended is not particularly limited, but is usually set appropriately within a range of 0.2 to 10 parts by weight with respect to 100 parts by weight of the total of the above-mentioned photopolymerizable prepolymer and photopolymerizable monomer. Good.

The hard coat layer may contain various additives as long as the effects of the present invention are not excessively impaired. As various additives, surface modifiers, lubricants, colorants, pigments, dyes, optical brighteners, flame retardants, antibacterial agents, antifungal agents, ultraviolet absorbers, light stabilizers, heat stabilizers, antioxidants, Examples thereof include a plasticizer, a leveling agent, a flow control agent, a defoaming agent, a dispersant, a storage stabilizer, a cross-linking agent, and a silane coupling agent, but are not particularly limited thereto.

Alternatively, a cured film of an ionizing radiation-curable organic-inorganic hybrid hard coat agent (hereinafter, also simply referred to as “hybrid hard coat agent”) can be used as the hard coat layer. The hybrid hard coat agent is not particularly limited, but one containing reactive silica particles (hereinafter, also simply referred to as “reactive silica particles”) in which at least a photosensitive group having photopolymerization reactivity is introduced on the surface thereof. Can be mentioned. Here, examples of the photosensitive group having photopolymerization reactivity include a polymerizable unsaturated group represented by a (meth)acryloyloxy group. Further, as a hybrid hard coating agent, a compound capable of undergoing a photopolymerization reaction with a photosensitive group having photopolymerization reactivity introduced on the surface of the reactive silica particles, for example, an unsaturated organic compound having a polymerizable unsaturated group, It may include one. These hybrid hard coating agents can be used as a liquid mixture obtained by mixing or dissolving the reactive silica particles or the unsaturated organic compound having a polymerizable unsaturated group described above with a known solvent.

The average particle diameter of the reactive silica particles is not particularly limited, but is preferably 0.001 to 0.1 μm, more preferably 0.001 to 0.01 μm. Examples of such reactive silica particles include powdery silica or colloidal silica as a matrix, a hydrolyzable silyl group, a polymerizable unsaturated group, and a group represented by the following general formula (1) in the molecule. And a compound having a group represented by (2) (hereinafter, also referred to as “polymerizable unsaturated group-modified hydrolyzable silane”) chemically bonded via a silyloxy group can be used. .. That is, the polymerizable unsaturated group-modified hydrolyzable silane, by the hydrolysis reaction of the hydrolyzable silyl group, between the silica particles, to form a silyloxy group and chemically bonded, It can be used as a reactive silica particle. Examples of the hydrolyzable silyl group include an alkoxylyl group, a carboxylylate silyl group such as an acetoxysilyl group, a halogenated silyl group such as a chlorosilyl group, an aminosilyl group, an oxime silyl group, and a hydride silyl group. It is not particularly limited to. Examples of the polymerizable unsaturated group include an acryloyloxy group, a methacryloyloxy group, a vinyl group, a propenyl group, a butadienyl group, a styryl group, an ethynyl group, a cinnamoyl group, a malate group, and an acrylamide group. Not limited.

（式中、Ｘは、−ＮＨ−、酸素原子又は硫黄原子を表し、Ｙは、酸素原子又は硫黄原子を表し、但し、Ｘが酸素原子のときＹは硫黄原子である。）

(In the formula, X represents —NH—, an oxygen atom or a sulfur atom, Y represents an oxygen atom or a sulfur atom, provided that when X is an oxygen atom, Y is a sulfur atom.)

As the unsaturated organic compound having a polymerizable unsaturated group, a polyvalent unsaturated organic compound having two or more polymerizable unsaturated groups in the molecule, or a monovalent compound having one polymerizable unsaturated group in the molecule An unsaturated organic compound etc. can be mentioned.

Here, as the polyunsaturated organic compound, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, glycerol di(meth)acrylate, glycerol tri(meth)acrylate, 1,4-butanediol di( (Meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dicyclopentanyl di(meth)acrylate, pentaerythritol tri(meth)acrylate Acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di( Examples thereof include (meth)acrylate, tripropylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate.

Examples of monounsaturated organic compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, and lauryl. (Meth)acrylate, stearyl (meth)acrylate, allyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl ( (Meth)acrylate, glycerol (meth)acrylate, glycidyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, butoxyethyl (meth) Acrylate, 2-methoxyethyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 2-methoxypropyl (meth)acrylate, methoxydipropylene glycol (meth ) Acrylate, methoxytripropylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate and the like.

The cured film of the hybrid hard coat agent, in addition to the reactive silica particles and the compound capable of photopolymerization reaction, an auxiliary agent such as a photopolymerization initiator, a photopolymerization accelerator, a sensitizer (for example, an ultraviolet sensitizer), It may contain a thermoplastic resin, a thermosetting resin, an ionizing radiation curable resin, or the like. Further, from the viewpoint of improving antiglare properties, it contains silica such as porous silica, a matting agent such as alumina, talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, aluminum hydroxide, titanium dioxide, zirconium oxide. May be

The thickness of the functional layer 21 can be appropriately set and is not particularly limited, but is preferably 0.001 to 20 μm, more preferably 0.005 to 15 μm, and further preferably 0.01 to 10 μm. For example, when the functional layer 21 is a hard coat layer, the thickness is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and further preferably 2 to 10 μm. On the other hand, when the functional layer 21 is an index matching layer, the thickness is preferably 0.001 to 7 μm, more preferably 0.005 to 5 μm, and further preferably 0.01 to 3 μm.

When the functional layer 21 is a hard coat layer, its surface hardness is not particularly limited, but is preferably H or higher, more preferably 2H or higher, and further preferably 3H or higher. The surface hardness value is indicated by a pencil scratch value (pencil hardness) measured by a method according to JIS-K5400 (1990).

[Adhesive layer and separator layer]
Hereinafter, the pressure-sensitive adhesive layer 31 and the separator layer 41 will be described in detail. The pressure-sensitive adhesive layer 31 serves as a sticking surface of the separator layer 41, and serves as a sticking surface of a cover glass or a plastic substrate of the touch panel when used as a touch panel substrate. When the functional layer 21 such as a hard coat layer is also provided on the surface 11b side of the transparent substrate 11, the pressure-sensitive adhesive layer 31 and the separator layer 41 can be provided on the functional layer 21.

As the pressure-sensitive adhesive layer 31, any known material can be appropriately used as long as it can adhere the separator layer 41 and the cover glass of the touch panel, and is not particularly limited. Specifically, natural rubber-based, recycled rubber-based, chloroprene rubber-based, nitrile rubber-based, styrene-butadiene-based, silicone-based elastomer adhesives, acrylic-based, polyester-based, epoxy-based, urethane-based, cyanoacrylate-based, Examples thereof include silicone-based synthetic resin pressure-sensitive adhesives, emulsion-based pressure-sensitive adhesives, etc., but are not particularly limited thereto. From the viewpoint of easy adjustment of adhesive strength, handleability, productivity, etc., it is preferable to use a curable adhesive that is cured by irradiation with ionizing radiation or heating.

As the curable adhesive that is cured by irradiation with ionizing radiation, it is preferable to use at least one that is formed from a coating material that can be crosslinked and cured by irradiation with ionizing radiation. Examples of such an ionizing radiation curable coating material include a photo-cationic polymerizable resin capable of photo-cationic polymerization, a photo-polymerizable prepolymer capable of photo-radical polymerization, and a photo-polymerizable monomer. Further, the ionizing radiation-curable coating material may contain various additives. For example, in the case of curing with ultraviolet rays, it is preferable to contain a photopolymerization initiator, an ultraviolet sensitizer and the like.

As the curable adhesive that is cured by heating, a thermosetting resin that can be cross-linked and cured by heat below the heat resistant temperature of the transparent substrate 11 is preferable from the viewpoint of the heat effect of wet application and heat treatment. Examples thereof include melamine-based, epoxy-based, aminoalkyd-based, urethane-based, acrylic-based, polyester-based, and phenol-based crosslinkable resins, but are not particularly limited thereto. Such a thermosetting adhesive preferably contains a curing agent from the viewpoint of increasing crosslinkability and coating film hardness. Here, as the curing agent, known ones such as a polyfunctional isocyanate curing agent, a polyfunctional amine curing agent, a polycarboxylic acid curing agent, and an epoxy curing agent can be used. Among these, the combination of the acrylic thermosetting resin and the polyfunctional isocyanate curing agent is preferable from the viewpoint of a balance of high surface hardness, appropriate easy peeling property, and high adhesion. The compounding amount of the curing agent is not particularly limited. For example, when a commercially available curable adhesive is used, it may be appropriately adjusted based on the amount recommended by the manufacturer of the commercial product. If necessary, a fluorine resin, a silicone resin, a silicone oil, a silane coupling agent such as epoxysilane or aminosilanesilane, a polyvinyl alcohol resin, etc. may be contained.

Although the thickness of the pressure-sensitive adhesive layer 31 is not particularly limited, it is preferably 1 to 125 μm, more preferably 10 to 100 μm, from the viewpoint of a thin film of the laminate, a balance between appropriate easy peelability and high adhesion. The thickness is more preferably 10 to 50 μm, and particularly preferably 15 to 45 μm.

As the separator layer 41, a conventionally known one can be used, and the type thereof is not particularly limited. Polyethylene film, polypropylene film, polybutene film, polyethylene terephthalate film, polyethylene naphthalate film, polyester film, polybutadiene film, polymethylpentene film, polycarbonate film, polyvinyl chloride film, ethylene-vinyl acetate copolymer film, vinyl chloride copolymerization Various grades of plastic films such as united films are commercially available. In addition, these plastic films include silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, release treatment with silica powder or antifouling treatment, coating type, kneading type, vapor deposition type, etc. The antistatic treatment may be applied.

The thickness of the separator layer 41 is not particularly limited, but from the viewpoint of thinning the laminate (for example, a transparent hard coat film with a pressure-sensitive adhesive layer, a transparent conductive film substrate with a pressure-sensitive adhesive layer) after removing the separator layer 41. Therefore, the thickness is preferably 20 to 150 μm, more preferably 25 to 125 μm, still more preferably 50 to 125 μm.

As described above, from the viewpoint of suppressing various manufacturing troubles associated with thinning of the transparent substrate 11, particularly peeling off the end of the separator layer 41 to improve the handling property in the manufacturing process, the separator layer 41 with respect to the adhesive layer 31 has a temperature of 23° C. 50. The 15-degree peel force at %RH is required to be 2.00 N/25 mm width or more (peel rate 50 mm/min). The width is preferably 2.30 N/25 mm width or more, more preferably 2.50 N/25 mm width or more. According to the knowledge of the present inventors, even if the 90-degree peeling force and the 180-degree peeling force which are mainly used for the evaluation of the adhesiveness are good, the end portion peeling of the separator layer 41 unintentionally occurs. It is known to occur. That is, the peeling force of the separator layer 41 has an angle dependency, and in order to effectively suppress the edge peeling of the separator layer 41, the peeling force of the separator layer 41 is not 15 degrees or 180 degrees, but 15 degrees. It has been newly found by the present inventors that adjusting the peeling force is effective. The upper limit of the peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 is not particularly limited, but if the peeling force is too large, a zipping phenomenon will occur when the separator layer 41 is peeled off. It is desirable to set it.

Here, in the present specification, the peeling force of the separator layer 41 with respect to the adhesive layer 31 is measured using a light load type adhesion/film peeling analysis device VPA-3 (manufactured by Kyowa Interface Science Co., Ltd.) based on the flat plate cross stage method. Means the value to be set. The test procedure is as described in Examples described later.

Further, from the viewpoint of preventing peeling failure during work, the 90-degree peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 at 23° C. and 50% RH is 0.05 N/25 mm width or more (peeling speed 150 mm/min). It is preferable. The upper limit is not particularly limited, but is preferably 10 N/25 mm width or less, more preferably 5 N/25 mm width or less, and further preferably 3 N/25 mm, from the viewpoint of ensuring easy peelability of the separator layer 41. It is less than the width.

Further, from the viewpoint of enhancing the adhesiveness to the adherend such as the cover glass of the touch panel and improving the reliability, the 180 degree peeling force of the pressure-sensitive adhesive layer 31 to the adherend such as glass at 23° C. 50% RH. Is 10 N/25 mm width or more (peel rate 300 mm/min), more preferably 15 N/25 mm width or more (peel rate 300 mm/min).

The peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 described above can be adjusted, for example, by adjusting the formulation of the pressure-sensitive adhesive layer 31 or changing the type of the plastic film used for the separator layer 41. More specifically, the type and mixing ratio of the monomers and oligomers used in the pressure-sensitive adhesive layer 31 are changed, a thermoplastic resin is included in the pressure-sensitive adhesive layer 31, and a monomer having a high glass transition temperature such as acrylic acid or acrylamide is used. The peeling force can be adjusted by using an epoxy resin, an oligomer, or a polyfunctional monomer having a high crosslinking density to increase the crosslinking density after curing. Further, the peeling force can be adjusted by using a plastic film that has been subjected to a mold release treatment or an antifouling treatment as the separator layer 41. Furthermore, when a curable adhesive is used, the peeling force can be adjusted by the combined use of a photopolymerizable monomer or an unsaturated organic compound having a polymerizable unsaturated group and the mixing ratio thereof. Further, the peeling force can be adjusted by adjusting the irradiation energy of the ionizing radiation irradiation, the heating temperature, and the heating time during curing or post-curing. In addition, the peeling force can be adjusted by pressing the pressure-sensitive adhesive layer 31. For example, in the case of manufacturing or storing in a roll-to-roll mode, the peeling force is adjusted by adjusting the winding pressure. You can also The adjustment of the peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 is not particularly limited to these, and can be performed individually by any method or in an appropriate combination.

The transparent conductive film substrate 101 may further include various functional layers such as an anti-glare layer, an antireflection layer, an ultraviolet absorption layer, a Newton's ring suppression layer, and an index matching layer, if necessary. These functional layers can be provided on the outermost layer of the transparent conductive film substrate 101 or between any layers in the transparent conductive film substrate 101. These can be provided separately, but can also be provided as a single functional layer that performs multiple functions.

In the substrate for transparent conductive film 101 described in detail above, for example, after the functional layer 21 is formed on one surface 11a side of the transparent base material 11, the adhesive layer 31 and the separator are formed on the other surface 11b side of the transparent base material 11. It can be obtained by stacking the layers 41. The method for forming each of these layers may be performed according to a conventional method and is not particularly limited. As a suitable method for producing the functional layer 21 and the pressure-sensitive adhesive layer 31, there are conventionally known coating methods such as doctor coating, dip coating, roll coating, bar coating, die coating, blade coating, air knife coating, kiss coating, spray coating and spin coating. Are listed. As the solvent of the coating liquid used here, water; a ketone solvent such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; an ester solvent such as methyl acetate, ethyl acetate, butyl acetate; an ether solvent such as methyl cellosolve and ethyl cellosolve Alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and mixed solvents thereof, which are known in the art, can be used. The functional layer 21 and the pressure-sensitive adhesive layer 31 can be formed by subjecting the coating film thus coated to ionizing radiation treatment, heat treatment, and/or pressure treatment as necessary. Further, as a suitable method for producing the separator layer 41, dry lamination can be mentioned. In addition, as a pretreatment before laminating each layer, an anchor treatment, a corona treatment, or the like can be performed as necessary.

The light source used in the irradiation of ionizing radiation is not particularly limited. For example, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, an electron beam accelerator, etc. can be used. Further, the irradiation amount at this time can also be appropriately set according to the type of light source used, output performance, etc., and is not particularly limited. The irradiation amount of ultraviolet rays is generally about 100 to 6,000 mJ/cm ^{2 of} integrated light amount. Is used as a guide.

Moreover, the heat source used in the heat treatment is not particularly limited. Both contact type and non-contact type can be preferably used. For example, a far infrared heater, a short wavelength infrared heater, a medium wavelength infrared heater, a carbon heater, an oven, a heat roller or the like can be used. The treatment temperature in the heat treatment is not particularly limited, but is generally 80 to 200°C, preferably 100 to 150°C.

In the substrate for transparent conductive film 101 of the present embodiment, since the pressure-sensitive adhesive layer 31 and the separator layer 41 are provided on the one surface 11b side of the transparent base material 11, not only is the transparent base material 11 reinforced. When mounting the touch panel, the separator layer 41 can be peeled and removed and can be attached as it is, so that the number of steps can be reduced, and further, the thinning of the transparent substrate 11 can be promoted by the thickness of the separator layer 41. It is possible. Further, since the 15-degree peeling force of the separator layer 41 with respect to the adhesive layer 31 is 2.00 N/25 mm width or more (peeling speed 50 mm/min), unintentional partial peeling may occur at the outer peripheral edge portion of the separator layer 41. Suppressed. Therefore, it can be said that the transparent conductive film substrate 101 is excellent in handleability even if the transparent substrate 11 is thinned, and that precise layered formation of each layer is easy.

(Second embodiment)
FIG. 2 is a schematic cross-sectional view showing the main part of the touch panel substrate 201 of the present embodiment. The touch panel substrate 201 includes a transparent base material 11, an index matching layer as the functional layer 21, an adhesive layer 31, a separator layer 41, and a transparent conductive film 61. The functional layer 21 and the transparent conductive film 61 are provided on the one surface 11a side of the transparent base material 11, and the adhesive layer 31 and the separator layer 41 are on the opposite side, that is, one surface of the transparent base material 11. It is provided on the 11b side. The 15-degree peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 is set to be 2.00 N/25 mm width or more (peeling speed 50 mm/min). In other words, the touch panel substrate 201 has a configuration in which the transparent conductive film 61 is provided on the functional layer 21 of the transparent conductive film substrate 101 of the first embodiment described above. That is, since the structure of the transparent conductive film substrate 101 is the same as that of the above-described first embodiment, duplicate description thereof is omitted here.

Various known transparent conductive films can be used as the transparent conductive film 61, and the type thereof is not particularly limited. For example, thin films of conductive materials such as indium oxide, tin oxide, indium tin oxide, and silver nanowires, conductive materials such as polyparaphenylene, polyacetylene, polyaniline, polythiophene, polyparaphenylenevinylene, polypyrrole, polyfuran, polyselenophene, and polypyridine. A thin film of a conductive polymer or a metal mesh thin film of gold, silver, copper, palladium or the like can be used.

The transparent conductive layer 61 can be formed using the above-described conductive material by a dry process such as a vacuum deposition method, a sputtering method, an ion plating method, a solution coating method, a wet process such as a lithography method, or the like.

The thickness of the transparent conductive layer 61 can be appropriately set according to the material used and the application, and is not particularly limited. Generally, the thickness is such that the surface resistivity is 1000Ω or less, preferably 500Ω or less, more preferably 300Ω or less. Specifically, the thickness of the transparent conductive layer 61 is preferably 10 nm or more, more preferably 20 nm or more. In consideration of economy, the thickness is preferably 80 nm or less, more preferably 70 nm or less. Further, the total light transmittance is usually preferably 80% or more, more preferably 85% or more, still more preferably 88% or more.

Also in the touch panel substrate 201 of the present embodiment, since the pressure-sensitive adhesive layer 31 and the separator layer 41 are provided on the one surface 11b side of the transparent base material 11, not only the transparent base material 11 is reinforced, but also the touch panel. Since the separator layer 41 can be peeled off and attached at the time of mounting, it is possible to reduce the number of steps, and further, it is possible to promote the thinning of the transparent substrate 11 by the thickness of the separator layer 41. is there. Further, since the 15-degree peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 is set to 2.00 N/25 mm width or more (peeling speed 50 mm/min), unintended partial peeling of the outer peripheral edge portion of the separator layer 41 is prevented. Generation is also suppressed. Therefore, it can be said that the touch panel substrate 201 has excellent handleability even if the transparent substrate 11 is made thin, and facilitates precise layered formation of each layer.

(Third Embodiment)
FIG. 3 is a schematic cross-sectional view showing a main part of the transparent adhesive substrate 301 for the transparent conductive film of this embodiment. The transparent adhesive substrate 301 includes an adhesive layer 31 and separator layers 41 and 42 provided on the one surface 31a side and the other surface 31b side of the adhesive layer 31. The 15-degree peeling force of the separator layers 41 and 42 with respect to the pressure-sensitive adhesive layer 31 is set to be 2.00 N/25 mm width or more (peeling speed 50 mm/min).

The transparent adhesive substrate 301 is a member used to apply the adhesive layer 31 and the separator layer 41 in the transparent conductive film substrate 101 and the touch panel substrate 201 described above. That is, the separator layer 42 of the transparent pressure-sensitive adhesive substrate 301 is peeled and removed, and the exposed pressure-sensitive adhesive layer 31 is attached to the above-mentioned transparent substrate 11, whereby the pressure-sensitive adhesive layer 31 and the separator are formed on the transparent substrate 11. The layer 41 is transferred. Since the configurations of the pressure-sensitive adhesive layer 31 and the separator layer 41 are the same as those in the above-described first embodiment, duplicated description here will be omitted.

In the present embodiment, the separator layer 42 has the same configuration as the separator layer 41 of the above-described first embodiment. That is, as the separator layer 42, a conventionally known one can be used, and the type thereof is not particularly limited. Polyethylene film, polypropylene film, polybutene film, polyethylene terephthalate film, polyethylene naphthalate film, polyester film, polybutadiene film, polymethylpentene film, polycarbonate film, polyvinyl chloride film, ethylene-vinyl acetate copolymer film, vinyl chloride copolymerization Various grades of plastic films such as united films are commercially available. In addition, these plastic films include silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, release treatment with silica powder or antifouling treatment, coating type, kneading type, vapor deposition type, etc. The antistatic treatment may be applied.

The thickness of the separator layer 42 is not particularly limited, but is preferably 20 to 150 μm, more preferably 23 to 125 μm, and further preferably 50 to 125 μm. The thickness of the separator layer 42 may be the same as or different from the thickness of the separator layer 41.

According to this transparent pressure-sensitive adhesive substrate 301, a laminated body having a 15-degree peeling force of the separator layer 41 with respect to the pressure-sensitive adhesive layer 31 of 2.00 N/25 mm width or more (peeling speed 50 mm/min) can be easily formed on the transparent substrate 11. Can be transferred to. Therefore, by using the transparent adhesive substrate 301, the transparent conductive film substrate 101 and the touch panel substrate 201 can be reproducibly processed with excellent handleability even when the transparent substrate 11 is made into a thin film, and it is easy to form a precise laminated layer. Can be realized.

Hereinafter, the present invention will be described in detail based on actual measurement data, but the present invention is not limited thereto. The present invention can employ various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention. In the following, "parts" means "parts by mass" unless otherwise specified.

<Measurement of 15-degree peel force and 90-degree peel force>
Based on the flat plate cross stage method, a light load type adhesion/film peeling analysis device VPA-3 (manufactured by Kyowa Interface Science Co., Ltd.) was used to perform the measurement in the following procedure.
(1) A sample having a width of 25 mm is cut out from the transparent conductive film substrate.
(2) The glass support of the device and the outermost surface of the sample separator layer are attached to each other using a strongly adhesive double-sided tape.
(3) The glass support is set in the device, the end of the separator layer is peeled from the pressure-sensitive adhesive layer 31, and the pressure-sensitive adhesive layer side (transparent base material and pressure-sensitive adhesive layer) is attached to the movable part of the measuring device.
(4) A peeling test is performed while maintaining a predetermined peeling angle and a predetermined peeling angle.
Test conditions Test environment: 23°C 50%RH
Peeling force of 15 degrees: Peeling angle of 15 degrees, and peeling speed: 50 mm/min
90 degree peeling force: 90 degree peeling angle, and peeling speed: 150 mm/min

<Evaluation of Separation of Edge of Separator Layer>
After curling the substrate for transparent conductive film with a radius of curvature of 20 cm, the peeling state of the separator layer was visually observed and evaluated according to the following criteria.
○ No peeling at the edges of the separator layer is observed.
× Separation of the edge of the separator layer was observed, and 3 cm or more floated from the edge.

(Examples 1 to 6)
Samples of Examples 1 to 6 were prepared by applying an acrylic adhesive on a PET support having a thickness of 50 μm to form a pressure-sensitive adhesive layer having a thickness of 25 μm, and dry-laminating a separator on the pressure-sensitive adhesive layer. did. In addition, the addition amount of the curing agent represents the solid content of the curing agent with respect to 100 parts by mass of the resin solid content of the pressure-sensitive adhesive. With respect to the obtained samples of Examples 1 to 6, the 15-degree peeling force and the 90-degree peeling force were measured and the edge peeling of the separator layer was evaluated. Table 1 shows the type of each material used and the evaluation results.

101... Substrate for transparent conductive film 11... Transparent base material 11a... Surface 11b... Surface 21... Functional layer 31... Adhesive layer 31a... Surface 31b... Surface 41・・・Separator layer 42 ・・・Separator layer 61 ・・・Transparent conductive film 201 ・・・Touch panel substrate 301 ・・・Transparent adhesive base material

Claims (7)

A substrate for a transparent conductive film comprising a transparent base material,
On one surface side of the transparent substrate, an adhesive layer and a separator layer are provided in this order,
The 15° peeling force of the separator layer with respect to the pressure-sensitive adhesive layer at 23° C. 50% RH is 2.00 N/25 mm width or more (peeling speed 50 mm/min), and the separator layer with respect to the pressure-sensitive adhesive layer has a temperature of 23° C. 50° C. A substrate for a transparent conductive film, which has a 90 degree peeling force at %RH of 0.05 N/25 mm width or more at a peeling speed of 150 mm/min. At least one functional layer selected from the group consisting of a hard coat layer, an anti-fingerprint layer, an antifouling layer, an anti-blocking layer, an anti-glare layer, an anti-reflection layer, an ultraviolet absorbing layer, a Newton's ring suppressing layer, and an index matching layer. Further comprising,
The substrate for transparent conductive film according to claim 1. The transparent substrate has a thickness of 10 to 150 μm,
The substrate for transparent conductive film according to claim 1. The functional layer has a thickness of 0.001 to 20 μm
The substrate for transparent conductive film according to claim 2 . A substrate for a touch panel comprising a transparent conductive film and a transparent base material,
On one surface side of the transparent substrate, an adhesive layer and a separator layer are provided in this order,
On the other surface side of the transparent substrate, the transparent conductive film is provided,
The 15° peeling force of the separator layer with respect to the pressure-sensitive adhesive layer at 23° C. 50% RH is 2.00 N/25 mm width or more (peeling speed 50 mm/min), and the separator layer with respect to the pressure-sensitive adhesive layer has a temperature of 23° C. 50° C. A substrate for a touch panel, wherein the 90 degree peeling force at %RH is 0.05 N/25 mm width or more at a peeling speed of 150 mm/min. At least one functional layer selected from the group consisting of a hard coat layer, an anti-fingerprint layer, an antifouling layer, an anti-blocking layer, an anti-glare layer, an anti-reflection layer, an ultraviolet absorbing layer, a Newton's ring suppressing layer, and an index matching layer. Further equipped with,
On the other surface side of the transparent substrate, the functional layer and the transparent conductive film are provided in this order,
The touch panel substrate according to claim 5. A transparent pressure-sensitive adhesive substrate for a transparent conductive film, comprising a pressure-sensitive adhesive layer and a separator layer provided on one surface side and the other surface side of the pressure-sensitive adhesive layer,
The 15-degree peel force at 23° C. and 50% RH of the separator layer provided on the one surface side with respect to the pressure-sensitive adhesive layer is 2.00 N/25 mm width or more (peeling speed 50 mm/min), A transparent pressure-sensitive adhesive substrate for a transparent conductive film, wherein the separator layer has a 90° peel force at 23° C. and 50% RH of 0.05 N/25 mm width or more at a peeling speed of 150 mm/min.

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