JP2015199206A - Transparent conductive poly(meth)acrylimide-based resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film having excellent transparency, rigidity, heat resistance, dimension stability, surface hardness on the touch surface side and conductivity and to provide a one plastic solution for substituting, what is called, a one glass solution.SOLUTION: There is provided a transparent conductive film in which a hard coat and a transparent conductive film are formed in this order on at least one surface of a poly(meth)acrylimide-based resin film.

Description

The present invention relates to a transparent conductive film. More specifically, the present invention relates to a transparent conductive film used for image display devices such as a liquid crystal display, a plasma display, and an electroluminescence display.

In recent years, touch panels that are installed on image display devices such as a liquid crystal display, a plasma display, and an electroluminescence display and can be input by touching with a finger or a pen while watching the display have become widespread.

Conventionally, a display base plate of a touch panel and a transparent conductive substrate meet the required characteristics such as heat resistance, dimensional stability, high transparency, high surface hardness, and high rigidity. Have been used. On the other hand, glass has problems such as low impact resistance and easy cracking; low workability; difficult to handle; high specific gravity and heavy; difficult to meet demands for curved display and flexibility. Especially in mobile terminals such as smartphones and tablet terminals, being heavy is a big problem that may impair the product power.

Therefore, a two-layer touch panel (so-called one glass solution) in which a touch sensor is directly formed on the back side of the display face plate has been proposed. However, it is still heavy and insufficient for mobile terminals.

In addition, materials that replace glass have been actively researched and have excellent surface hardness and scratch resistance on the surface of transparent resin film substrates such as triacetylcellulose, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and norbornene polymers. Many hard coat laminated bodies in which a hard coat is formed have been proposed (for example, Patent Document 1). However, its heat resistance and dimensional stability are inadequate, and when forming a transparent conductive film, it is necessary to maintain a high process temperature to increase the crystallinity of the transparent conductive film and reduce the specific resistance. Process temperature cannot be raised due to insufficient heat resistance of film substrate; further thin film transistor is formed on transparent conductive laminated film due to insufficient heat resistance of transparent resin film substrate. Can not;

Therefore, “a polyimide film having a transmittance of 80% or more in the wavelength region of 440 nm to 780 nm, a thermal expansion coefficient of 15 ppm / K or less, and a glass transition temperature of 300 ° C. or more” has been proposed as a transparent resin film substrate. (Patent Document 2). However, since the polyimide film is obtained by molding a raw material polyamic acid resin solution by a casting method or the like, it is industrially difficult to obtain a thick film and cannot be used as a display face plate. .

JP 2013-208896 A JP 2014-019108 A

An object of the present invention is to provide a transparent conductive film excellent in transparency, rigidity, heat resistance, dimensional stability, surface hardness on the touch surface side, and conductivity. The second object of the present invention is to provide a one plastic solution that replaces the so-called one glass solution.

As a result of earnest research, the present inventor has found that the above problem can be achieved by forming a transparent conductive film on the hard coat surface of the laminate of the poly (meth) acrylimide resin film and the hard coat. I found it.

That is, the present invention is a transparent conductive film characterized in that a hard coat and a transparent conductive film are formed in this order on at least one surface of a poly (meth) acrylimide resin film.

According to a second aspect of the present invention, the poly (meth) acrylimide resin film comprises a first poly (meth) acrylimide resin layer (α1); an aromatic polycarbonate resin layer (β); a second poly (meth) acrylic. The transparent conductive film according to the first invention, wherein the imide resin layer (α2) is a transparent multilayer film directly laminated in this order.

3rd invention is the transparent conductive film as described in 1st invention or 2nd invention, wherein the thickness of the said poly (meth) acrylimide-type resin film is 100-1500 micrometers.

4th invention has a 1st hard coat (H1); the layer of a poly (meth) acrylimide-type resin film; 2nd hard coat (H2); and a transparent conductive film in order from the outermost layer side. The transparent conductive film according to any one of the first to third inventions.

A fifth invention is any one of the first to fourth inventions, wherein the transparent conductive film of the transparent conductive film has a surface resistivity of 120 Ω / sq or less and a total light transmittance of 85% or more. 1. The transparent conductive film according to 1.

A sixth invention is an image display device using the transparent conductive film according to any one of the first to fifth inventions.

A seventh invention is the use of the transparent conductive film according to any one of the first to fifth inventions as an image display device member.

The transparent conductive film of the present invention is excellent in transparency, rigidity, heat resistance, dimensional stability, surface hardness on the touch surface side, and conductivity. Therefore, it can be suitably used for an image display device such as a liquid crystal display, a plasma display, and an electroluminescence display, particularly for an image display device used for a mobile terminal such as a smartphone or a tablet terminal. Further, it can be suitably used as a one plastic solution that replaces the so-called one glass solution.

The transparent conductive film of the present invention is characterized in that a hard coat and a transparent conductive film are formed in this order on at least one surface of a poly (meth) acrylimide resin film.

The transparent conductive film of the present invention is a laminate in which a hard coat is formed on at least one surface of a poly (meth) acrylimide resin film (hard coat (in the case of the fourth invention, the second hard coat (H2)). The laminated body before forming a transparent conductive film on top of (), which may hereinafter be abbreviated as “hard coat laminated body”). Therefore, it becomes excellent in transparency, rigidity, heat resistance, and dimensional stability. Moreover, since the said hard-coat laminated body is excellent in heat resistance and dimensional stability, it can form the transparent conductive film excellent in electroconductivity.

The poly (meth) acrylimide resin film and the hard coat are both highly transparent and colored so that the transparent conductive film of the present invention can be suitably used as a member of an image display device. It is required that there is no. Therefore, the hard coat laminate preferably has a total light transmittance (measured using a turbidimeter “NDH2000 (trade name)” manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K 7361-1: 1997). It is 88% or more, more preferably 90% or more, and still more preferably 92% or more. A higher total light transmittance is preferable. The haze (measured using a turbidimeter “NDH2000 (trade name)” of Nippon Denshoku Industries Co., Ltd. according to JIS K 7136: 2000) is preferably 2.0% or less, more preferably 1.5%. % Or less. The lower the haze, the better. Further, the yellowness index (measured using a chromaticity meter “SolidSpec-3700 (trade name)” manufactured by Shimadzu Corporation in accordance with JIS K 7105: 1981) is preferably 3 or less, more preferably 2 or less, and even more preferably. Is 1 or less. The lower the yellowness index, the better.

The above poly (meth) acrylimide resin introduces the characteristics of excellent heat resistance and dimensional stability of polyimide resin while maintaining the characteristics of acrylic resin such as high transparency, high surface hardness and high rigidity. Is a thermoplastic resin that has improved the disadvantage of being colored reddish brown, and is disclosed in, for example, JP-T-2011-519999. In the present specification, poly (meth) acrylimide means polyacrylimide or polymethacrylamide.

The poly (meth) acrylimide resin is not limited except that it has high transparency and is not colored for the purpose of using the laminate for an optical article, and any poly (meth) acrylic resin. An imide resin can be used.

A preferable example of the poly (meth) acrylimide resin is a yellowness index (measured according to JIS K 7105: 1981 using a chromaticity meter “SolidSpec-3700 (trade name)” manufactured by Shimadzu Corporation). 3 or less can be mentioned. The yellowness index is more preferably 2 or less, and even more preferably 1 or less. From the viewpoint of the extrusion load and the stability of the molten film, it is preferable that the melt mass flow rate (measured in accordance with ISO 1133 under the conditions of 260 ° C. and 98.07 N) is 0.1 to 20 g / 10 min. it can. The melt mass flow rate is more preferably 0.5 to 10 g / 10 min. Further, the glass transition temperature of the poly (meth) acrylimide resin is preferably 150 ° C. or higher from the viewpoint of heat resistance. More preferably, it is 170 degreeC or more.

The poly (meth) acrylimide resin may be a thermoplastic resin other than the poly (meth) acrylimide resin; a pigment, an inorganic filler, an organic filler, and a resin filler, as long as it does not contradict the purpose of the present invention. An additive such as a lubricant, an antioxidant, a weather resistance stabilizer, a heat stabilizer, a mold release agent, an antistatic agent, and a surfactant may be further included. The blending amount of these optional components is usually about 0.01 to 10 parts by mass when the poly (meth) acrylimide resin is 100 parts by mass.

Commercial examples of the poly (meth) acrylimide resin include “PLEXIMID TT70 (trade name)” manufactured by Evonik.

The thickness of the poly (meth) acrylimide resin film is not particularly limited, and can be any thickness as desired. When the transparent conductive film of the present invention is used by being laminated with another substrate such as a glass plate or an acrylic plate, it may be usually 20 μm or more, preferably 50 μm or more from the viewpoint of handleability. Moreover, from an economical viewpoint, it may be 250 micrometers or less normally, Preferably it may be 150 micrometers or less. When the transparent conductive film of the present invention is used as a display face plate, particularly when used as a one plastic solution to replace the so-called one glass solution, it is usually 100 μm or more, preferably from the viewpoint of maintaining rigidity. It may be 200 μm or more, more preferably 300 μm or more. Moreover, from a viewpoint of meeting the request | requirement of thickness reduction of a touchscreen, it may be 1500 micrometers or less normally, Preferably it is 1200 micrometers or less, More preferably, it may be 1000 micrometers or less.

The poly (meth) acrylimide resin film is preferably a first poly (meth) acrylimide resin layer (α1); an aromatic polycarbonate resin layer (β); a second poly (meth) acrylimide resin. Layer (α2); is a transparent multilayer film directly laminated in this order. In the present specification, the present invention will be described on the assumption that a transparent conductive film is formed on the α2 layer side.

Poly (meth) acrylimide resin is excellent in heat resistance and surface hardness, but machinability tends to be insufficient, whereas aromatic polycarbonate resin is excellent in machinability, but heat resistance And surface hardness tends to be insufficient. Therefore, by using the transparent multilayer film having the above-described layer structure, it is possible to easily obtain a transparent conductive film that compensates for the weaknesses of both and has excellent heat resistance, surface hardness, and cutting workability. .

The layer thickness of the α1 layer is not particularly limited, but may be usually 20 μm or more, preferably 40 μm or more, more preferably 60 μm or more from the viewpoint of heat resistance and surface hardness of the transparent conductive film of the present invention.

The layer thickness of the α2 layer is not particularly limited, but is preferably the same layer thickness as the α1 layer from the viewpoint of curling resistance of the transparent conductive film of the present invention.

Here, the “same layer thickness” should not be interpreted as the same layer thickness in a physicochemically strict sense. It should be construed that the layer thickness is the same within the range of process and quality control that is usually performed industrially. This is because the curl resistance of the multilayer film can be kept good if the layer thickness is the same within the range of the amplitude of process and quality control that is usually performed industrially. In the case of an unstretched multilayer film by the T-die coextrusion method, since the process and quality are usually controlled with a width of about -5 to +5 μm, the layer thicknesses of 65 μm and 75 μm should be interpreted as the same. is there.

The layer thickness of the β layer is not particularly limited, but may be usually 20 μm or more, preferably 80 μm or more, and more preferably 120 μm or more from the viewpoint of cutting resistance of the transparent conductive film of the present invention.

The poly (meth) acrylimide resin used for the α1 layer and the α2 layer has been described above.

The poly (meth) acrylimide-based resin used for the α1 layer and the poly (meth) acrylimide-based resin used for the α2 layer have different resin characteristics, for example, poly (meth) with different melt mass flow rate and glass transition temperature. A (meth) acrylimide resin may be used, but from the viewpoint of curling resistance of the transparent conductive film of the present invention, a resin having the same resin characteristics is preferably used. For example, using the same lot of the same grade is one preferred embodiment.

Examples of the aromatic polycarbonate resin used for the β layer include aromatic dihydroxy compounds such as bisphenol A, dimethylbisphenol A, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, and phosgene. A polymer obtained by an interfacial polymerization method with an aromatic dihydroxy compound such as bisphenol A, dimethyl bisphenol A, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, and carbonic acid such as diphenyl carbonate. One or a mixture of two or more aromatic polycarbonate resins such as a polymer obtained by a transesterification reaction with a diester can be used.

As a preferable optional component that can be included in the aromatic polycarbonate-based resin, a core-shell rubber can be exemplified. When the total of the aromatic polycarbonate-based resin and the core-shell rubber is 100 parts by mass, the core-shell rubber is 0-30 parts by mass (aromatic polycarbonate-based resin 100-70 parts by mass), preferably 0-10 parts by mass (aromatic By using it in an amount of 100 to 90 parts by mass of a polycarbonate-based resin, it is possible to further improve cutting resistance and impact resistance.

Examples of the core shell rubber include methacrylic ester / styrene / butadiene rubber graft copolymer, acrylonitrile / styrene / butadiene rubber graft copolymer, acrylonitrile / styrene / ethylene / propylene rubber graft copolymer, and acrylonitrile / styrene / acrylic. Examples thereof include core-shell rubbers such as acid ester graft copolymers, methacrylic ester / acrylic ester rubber graft copolymers, and methacrylic ester / acrylonitrile / acrylic ester rubber graft copolymers. One or two of these Mixtures of more than one species can be used.

The aromatic polycarbonate-based resin may be a thermoplastic resin other than the aromatic polycarbonate-based resin and the core-shell rubber; a pigment, an inorganic filler, an organic filler, a resin filler; An additive such as an antioxidant, a weather resistance stabilizer, a heat stabilizer, a mold release agent, an antistatic agent, and a surfactant may be further included. The compounding amount of these optional components is usually about 0.01 to 10 parts by mass when the total of the aromatic polycarbonate resin and the core-shell rubber is 100 parts by mass.

The production method for obtaining the poly (meth) acrylimide resin film is not particularly limited. For example, using a device including (A) an extruder and a T die, the poly (meth) acrylimide is obtained from the T die. A step of continuously extruding a molten film of a resin; (B) the poly (meth) acryl between the rotating or circulating first mirror body and the rotating or circulating second mirror body; And a step of supplying and pressing a molten film of an imide-based resin.

Similarly, the production method in the case where the poly (meth) acrylimide resin film is the transparent multilayer film is not particularly limited. For example, (A ′) a coextrusion apparatus including an extruder and a T die is used. , First poly (meth) acrylimide resin layer (α1); aromatic polycarbonate resin layer (β); second poly (meth) acrylimide resin layer (α2); Continuously co-extruding a molten film of a multilayer film from a T-die; (B ′) between a rotating or circulating first mirror body and a rotating or circulating second mirror body, And a step of supplying and pressing the molten film of the transparent multilayer film.

As the T die used in the step (A) or the step (A ′), any can be used, and examples thereof include a manifold die, a fish tail die, a coat hanger die, and the like.

Any coextrusion apparatus can be used, and examples thereof include a coextrusion apparatus such as a feed block system, a multi-manifold system, and a stack plate system.

Any extruder can be used as the extruder used in the step (A) or the step (A ′). For example, a single-screw extruder, a same-direction rotating twin-screw extruder, and a different-direction rotating two An example is a screw extruder.

In addition, in order to suppress deterioration of the poly (meth) acrylimide resin or the aromatic polycarbonate resin, it is one of preferable methods to purge the inside of the extruder with nitrogen.

Furthermore, since the poly (meth) acrylimide resin is a highly hygroscopic resin, it is preferably dried before being used for film formation. It is also one of preferable methods that the poly (meth) acrylimide resin dried by a dryer is directly transported from the dryer to the extruder and charged. The set temperature of the dryer is preferably 100 to 150 ° C. It is also a preferred method to provide a vacuum vent in the metering zone of the extruder, usually at the tip of the screw.

The temperature of the T die used in the step (A) or the step (A ′) is a continuous extrusion or coextrusion of a poly (meth) acrylimide resin melt film or a transparent multilayer film melt film. In order to perform the process to perform stably, it is preferable to set it at least 260 degreeC or more. More preferably, it is 270 degreeC or more. Moreover, in order to suppress deterioration of poly (meth) acrylimide resin or aromatic polycarbonate resin, the temperature of the T die is preferably set to 350 ° C. or lower.

The ratio (R / t) between the lip opening (R) and the thickness (t) of the resulting poly (meth) acrylimide resin film or transparent multilayer film is preferably 1 to 5. More preferably, it is 1.1-2.5. When the ratio (R / t) exceeds 5, the retardation may increase. If it is less than 1, the extrusion load may become excessive.

As said 1st mirror surface body used at the said process (B) or the said process (B '), a mirror roll, a mirror belt, etc. can be mention | raise | lifted, for example. As said 2nd mirror surface body, a mirror surface roll, a mirror surface belt, etc. can be mention | raise | lifted, for example.

The mirror roll is a roll having a mirror-finished surface, and is made of metal, ceramic, silicon rubber, or the like. Further, the surface of the mirror roll can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method, etc. for the purpose of protection from corrosion and scratches.

The mirror belt is a seamless belt made of a normal metal whose surface is mirror-finished. For example, the mirror belt is circulated between a pair of belt rollers. Further, the surface of the mirror belt can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method for the purpose of protection from corrosion and scratches.

By the film forming method, a poly (meth) acrylimide resin film or a transparent multilayer film excellent in transparency, surface smoothness, and appearance can be obtained. This is because the melted film of the poly (meth) acrylimide resin film or the transparent multilayer film is pressed between the first mirror body and the second mirror body, so that the first mirror body and the second mirror body are highly smooth. It can be considered that the surface state is transferred to the film and a defective portion such as a die stripe is corrected.

The surface temperature of the first mirror body is preferably 100 ° C. or higher so that the transfer of the surface state can be performed satisfactorily. More preferably, it is 120 degreeC or more, More preferably, it is 130 degreeC or more. Moreover, in order to prevent the appearance defect (peeling trace) accompanying peeling with the first mirror body from appearing on the film, the surface temperature of the first mirror body is preferably 200 ° C. or lower, more preferably 160 ° C. or lower.

The surface temperature of the second mirror body is preferably set to 20 ° C. or higher so that the transfer of the surface state can be performed satisfactorily. More preferably, it is 60 degreeC or more, More preferably, it is 100 degreeC or more. Moreover, in order to prevent the appearance defect (peeling trace) accompanying peeling with the second mirror surface from appearing on the film, the surface temperature of the second mirror surface is preferably 200 ° C. or lower, more preferably 160 ° C. or lower.

The surface temperature of the first mirror body is preferably higher than the surface temperature of the second mirror body. This is because the film is held in the first mirror body and sent to the next transfer roll.

Further, when forming the hard coat, adhesion to the hard coat on the hard coat forming surface or both surfaces of the poly (meth) acrylimide resin film or the transparent multilayer film, which becomes a transparent film substrate for forming the hard coat. In order to increase the strength, easy adhesion treatment such as corona discharge treatment or anchor coat formation may be performed in advance.

When the corona discharge treatment is performed, good interlayer adhesion strength can be obtained by setting the wetting index (measured in accordance with JIS K6768: 1999) to usually 50 mN / m or more, preferably 60 mN / m or more. become. Further, after the corona discharge treatment, an anchor coat may be further formed.

In the corona discharge treatment, a film is passed between an insulated electrode and a dielectric roll, a high frequency high voltage is applied to generate a corona discharge, and the film surface is treated. Oxygen and the like are ionized by the corona discharge and collide with the film surface, so that the resin molecular chain is broken or the oxygen-containing functional group is added to the resin molecular chain on the film surface, and the wetting index is increased.

The unit area and the treatment amount (S) per unit time of the corona discharge treatment are determined from the viewpoint of obtaining the above wetting index, and are usually 80 W · min / m ² or more, preferably 120 W · min / m ² or more. . In addition, if the processing amount (S) is too high, the film is deteriorated. Therefore, the processing amount (S) is preferably suppressed to 500 W · min / m ² or less. More preferably, it is 400 W · min / m ² or less.

The processing amount (S) is defined by the following equation.
S = P / (L ・ V)
Here, S: treatment amount (W · min / m ² ), P: discharge power (W), L: length of discharge electrode (m), V: line speed (m / min).

The anchor coating agent for forming the anchor coat is not limited except that it has high transparency and is not colored, such as polyester, acrylic, polyurethane, acrylic urethane, and polyester urethane. The well-known thing can be used. Of these, a thermoplastic urethane anchor coating agent is preferred from the viewpoint of improving the adhesive strength with the hard coat.

As the anchor coating agent, a paint containing a silane coupling agent can also be used. Silane coupling agents include hydrolyzable groups (for example, alkoxy groups such as methoxy group and ethoxy group; acyloxy groups such as acetoxy group; halogen groups such as chloro group; and the like) and organic functional groups (for example, amino groups, A silane compound having at least two different reactive groups such as a vinyl group, an epoxy group, a methacryloxy group, an acryloxy group, and an isocyanate group, and functions to improve the adhesive strength with the hard coat. Of these, a silane coupling agent having an amino group is preferred from the viewpoint of improving the adhesive strength with the hard coat.

The paint containing the silane coupling agent is a paint mainly containing a silane coupling agent (50% by mass or more as a solid content). Preferably, 75% by mass or more, more preferably 90% by mass or more of the solid content of the paint is the silane coupling agent.

Examples of the silane coupling agent having an amino group include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N- 2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, and the like, and one or a mixture of two or more thereof can be used. Can be used.

The method for forming the anchor coat using the anchor coat agent is not limited, and a known method can be used. Specifically, methods such as roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating can be used. At this time, any dilution solvent such as methanol, ethanol, 1-methoxy-2-propanol, nbutyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and acetone can be used as necessary. .

Further, the anchor coating agent includes an antioxidant, a weather resistance stabilizer, a light resistance stabilizer, an ultraviolet absorber, a heat stabilizer, an antistatic agent, a surfactant, and a colorant as long as the object of the present invention is not adversely affected. In addition, one or two or more additives such as an infrared shielding agent, a leveling agent, a thixotropic agent, and a filler may be included.

The thickness of the anchor coat is usually about 0.01 to 5 μm, preferably 0.1 to 2 μm.

As described above, the hard coat (in the case of the fourth invention, the second hard coat (H2)) is excellent in transparency and non-coloring properties, but is further in close contact with the transparent conductive film. It is preferable that it is excellent in property. When the adhesion between the hard coat and the transparent conductive film is evaluated by the following (e) cross-cut test, it is preferably class 1, more preferably class 0.

An active energy ray-curable resin composition can be exemplified as a preferable hard coat-forming coating material for forming such a hard coat.

The active energy ray-curable resin composition can be polymerized and cured by active energy rays such as ultraviolet rays and electron beams to form a hard coat. Examples of the composition include a compound having two or more isocyanate groups (—N═C═O) and / or a photopolymerization initiator.

Examples of the active energy ray-curable resin include polyurethane (meth) acrylate, polyester (meth) acrylate, polyacryl (meth) acrylate, epoxy (meth) acrylate, polyalkylene glycol poly (meth) acrylate, and polyether. (Meth) acryloyl group-containing prepolymer or oligomer such as (meth) acrylate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Lauryl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, phenyl (meth) acrylate Phenyl cellosolve (meth) acrylate, 2-methoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-acryloyloxyethyl hydrogen phthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl ( (Meth) acrylate and (meth) acryloyl group-containing monofunctional reactive monomers such as trimethylsiloxyethyl methacrylate; monofunctional reactive monomers such as N-vinylpyrrolidone and styrene; diethylene glycol di (meth) acrylate, neopentyl glycol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2,2′-bis (4- (meth) acrylo (Methoxy) acryloyl group-containing bifunctional reactive monomers such as 2,2′-bis (4- (meth) acryloyloxypolypropyleneoxyphenyl) propane; trimethylolpropane tri (meth) (Meth) acryloyl group-containing trifunctional reactive monomers such as acrylate and trimethylolethane tri (meth) acrylate; (meth) acryloyl group-containing tetrafunctional reactive monomers such as pentaerythritol tetra (meth) acrylate; and dipentaerythritol Examples of the resin include one or more selected from (meth) acryloyl group-containing hexafunctional reactive monomers such as hexaacrylate or the like, or one or more of the above as constituent monomers.

In the present specification, (meth) acrylate means acrylate or methacrylate.

Examples of the compound having two or more isocyanate groups in one molecule include methylene bis-4-cyclohexyl isocyanate; trimethylolpropane adduct of tolylene diisocyanate, trimethylolpropane adduct of hexamethylene diisocyanate, trimethylol of isophorone diisocyanate. Polyisocyanates such as propane adduct, isocyanurate of tolylene diisocyanate, isocyanurate of hexamethylene diisocyanate, isocyanurate of isophorone diisocyanate, biuret of hexamethylene diisocyanate; and urethanes such as block isocyanates of the above polyisocyanates A crosslinking agent etc. can be mention | raise | lifted. These can be used alone or in combination of two or more. Further, at the time of crosslinking, a catalyst such as dibutyltin dilaurate or dibutyltin diethylhexoate may be added as necessary.

Examples of the photopolymerization initiator include benzophenone, methyl-o-benzoylbenzoate, 4-methylbenzophenone, 4,4′-bis (diethylamino) benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl. Benzophenone compounds such as -4'-methyldiphenyl sulfide, 3,3 ', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone; benzoin, benzoin methyl ether, benzoin Benzoin compounds such as ethyl ether, benzoin isopropyl ether and benzyl methyl ketal; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, etc. Acetophenone compounds; anthraquinone compounds such as methylanthraquinone, 2-ethylanthraquinone, 2-amylanthraquinone; thioxanthone compounds such as thioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone; alkylphenones such as acetophenone dimethyl ketal Compounds; triazine compounds; biimidazole compounds; acyl phosphine oxide compounds; titanocene compounds; oxime ester compounds; oxime phenylacetate compounds; hydroxy ketone compounds; and aminobenzoate compounds. it can. These can be used alone or in combination of two or more.

In addition, the active energy ray-curable resin composition includes an antistatic agent, a surfactant, a leveling agent, a thixotropic agent, a stain-preventing agent, a printability improving agent, an antioxidant, and a weathering stabilizer, as desired. In addition, one or more additives such as a light-resistant stabilizer, an ultraviolet absorber, a heat stabilizer, a colorant, and a filler may be included.

Moreover, since the said active energy ray curable resin composition is diluted to the density | concentration which is easy to apply, it may contain the solvent as needed. The solvent is not particularly limited as long as it does not react with the components of the active energy ray-curable resin composition and other optional components, or does not catalyze (promote) the self-reaction (including deterioration reaction) of these components. Not. Examples thereof include 1-methoxy-2-propanol, ethyl acetate, nbutyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, and acetone.

As a preferable optional component, when forming a transparent conductive film mainly composed of indium oxide, silica (silicon dioxide); aluminum oxide, zirconia, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium Metal oxide fine particles such as tin oxide, antimony oxide and cerium oxide; metal fluoride fine particles such as magnesium fluoride and sodium fluoride; metal sulfide fine particles; metal nitride fine particles; metal fine particles; Can do. The adhesion between the hard coat and the transparent conductive film can be enhanced.

The particle diameter of the inorganic fine particles needs to be 300 nm or less in order to maintain the transparency of the hard coat. Preferably it is 200 nm or less, More preferably, it is 120 nm or less. On the other hand, there is no particular lower limit of the particle diameter, but normally available fine particles are fine at most about 1 nm. In this specification, the particle size of the inorganic fine particles is the particle size distribution curve measured using a laser diffraction / scattering particle size analyzer “MT3200II (trade name)” manufactured by Nikkiso Co., Ltd. It is the particle diameter at which the accumulation is 50% by mass.

The active energy ray-curable resin composition can be obtained by mixing and stirring these components.

The method for forming a hard coat using a hard coat forming paint such as an active energy ray-curable resin composition is not particularly limited, and a known method can be used. Specifically, methods such as roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating can be used.

The thickness of the hard coat is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more from the viewpoint of rigidity, heat resistance, and dimensional stability of the transparent conductive film of the present invention. It's okay. Moreover, from a viewpoint of the cutting process aptitude and web handling property of the transparent conductive film of this invention, Preferably it is 100 micrometers or less, More preferably, you may be 50 micrometers or less.

In addition, in order to improve the adhesion between the hard coat and the transparent conductive film, a corona discharge treatment is optionally performed before forming the transparent conductive film on the hard coat surface, and the wetting index (according to JIS K6768: 1999). Measurement)) may be 35 mN / m or more, preferably 50 mN / m or more.

The transparent conductive film of the present invention is preferably, in order from the outermost layer side, first hard coat (H1); layer of poly (meth) acrylimide resin film; second hard coat (H2); transparent conductive film Having

The second hard coat (H2) is a hard coat on which a transparent conductive film is formed, and has been described above.

The first hard coat (H1) is provided on the opposite side of the transparent conductive film forming side of the poly (meth) acrylimide resin film, and the transparent conductive film of the present invention is used as a display face plate. Is a hard coat serving as a touch surface. Therefore, the thing excellent in transparency, non-coloring property, surface hardness, and abrasion resistance is preferable.

The surface hardness of the first hard coat (H1) (pencil hardness measured according to the following (H)) is preferably 7H or more, more preferably 8H or more, and further preferably 9H or more.

Further, the scratch resistance (measured according to the following (1)) of the surface of the first hard coat (H1) is preferably 10,000 times or more, more preferably 30000 times or more.

The transparent conductive film is required to be excellent in transparency, non-colorability, and conductivity so that the transparent conductive film of the present invention can be suitably used as a member of an image display device. Therefore, the total light transmittance (measured in accordance with the following (A)) of the transparent conductive film of the present invention is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. A higher total light transmittance is preferable. The haze (measured according to the following (b)) is preferably 3.0% or less, more preferably 2.0% or less, and still more preferably 1.5% or less. The lower the haze, the better. The yellowness index (measured in accordance with (c) below) is preferably 3 or less, more preferably 2 or less, and even more preferably 1 or less. The lower the yellowness index, the better. Further, the surface resistivity (measured in accordance with (d) below) is preferably 150Ω / sq or less, more preferably 120Ω / sq or less, still more preferably 110Ω / sq or less, and most preferably 100Ω / sq or less.

The method for forming the transparent conductive film of the transparent conductive film of the present invention is not particularly limited, but from the viewpoint of forming a transparent conductive film excellent in transparency, non-colorability, and conductivity, for example, tin, Metal oxides such as indium oxide, cadmium oxide, and tin oxide doped with one or more of tellurium, cadmium, molybdenum, tungsten, fluorine, zinc, germanium, etc .; zinc oxide doped with aluminum, etc., and titanium oxide; Examples thereof include a method of forming a thin film of one kind or a mixture of two or more kinds by using an ion sputtering method, a vacuum deposition method, an ion plating method, a plasma chemical vapor deposition method, or the like.

Among the above metal oxides, indium oxide containing 2 to 15% by mass of tin oxide is preferable from the viewpoints of transparency, non-colorability, and conductivity.

In recent years, a transparent conductive film formed by wet-coating a paint has also been proposed (for example, JP-A-2014-037501). The transparent conductive film of the transparent conductive film of the present invention may be formed using these techniques.

The thickness of the transparent conductive film is not particularly limited, but may be usually 1 nm or more, preferably 5 nm or more from the viewpoint of reducing the surface resistivity. Moreover, from a transparency viewpoint, it may be 100 nm or less normally, Preferably it may be 60 nm or less. In the present specification, the thickness of the transparent conductive film is a value obtained by cutting an ultrathin section from the transparent conductive film using a focused ion beam and observing the section of the section using a transmission electron microscope. (The average value of a total of 15 values for 3 fields of view for 5 sections.)

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

Measurement method (a) Total light transmittance;
According to JIS K 7361-1: 1997, it measured using the turbidimeter "NDH2000 (brand name)" of Nippon Denshoku Industries Co., Ltd.

(B) Haze;
According to JIS K 7136: 2000, it measured using the turbidimeter "NDH2000 (brand name)" of Nippon Denshoku Industries Co., Ltd.

(C) Yellowness index;
In accordance with JIS K 7105: 1981, the measurement was performed using a chromaticity meter “SolidSpec-3700 (trade name)” manufactured by Shimadzu Corporation.

(D) Surface resistivity;
In accordance with JIS K 7194: 1994, a resistivity meter “Loresta GP MCP-T610 type (trade name)” manufactured by Mitsubishi Chemical Analytech Co., Ltd. is used, and the surface resistivity of the transparent conductive film is measured by a four-probe method (probe method). Was measured. For the electrical resistivity measurement method and its theory, the Mitsubishi Chemical Analytech website (http://www.mccat.co.jp/3seihin/genri/ghlup2.htm) can be referred to.

(E) Cross cut test (adhesion between hard coat and transparent conductive film);
In accordance with JIS K 5600-5-6: 1999, 100 square cuts (1 square = 1 mm × 1 mm) are made from the transparent conductive film of the transparent conductive film, and then a tape for adhesion test is applied to the grid. I attached it with my finger and peeled it off. Evaluation criteria were in accordance with Table 1 of the above JIS standard.
Classification 0: The edges of the cuts are completely smooth, and there is no peeling in any lattice eye.
Classification 1: Small peeling of the coating film at the intersection of cuts. It is clearly not more than 5% that the crosscut is affected.
Classification 2: The coating film is peeled along the edge of the cut and / or at the intersection. The cross-cut portion is clearly affected by more than 5% but not more than 15%.
Classification 3: The coating film is partially or completely peeled along the edge of the cut, and / or various parts of the eyes are partially or completely peeled off. The cross-cut portion is clearly affected by more than 15% but not more than 35%.
Classification 4: The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. The cross-cut portion is clearly affected by more than 35% but not more than 65%.
Category 5: When the degree of peeling exceeds Category 4.

(F) Linear expansion coefficient (thermal dimensional stability);
It measured according to JISK7197: 1991. A thermomechanical analyzer (TMA) “EXSTAR6000 (trade name)” manufactured by Seiko Instruments Inc. was used. The test piece was 20 mm in length and 10 mm in width, and was collected so that the machine direction of the poly (meth) acrylimide resin film was the vertical direction of the test piece. Conditioning of the test piece was performed at a temperature of 23 ° C. ± 2 ° C. and a relative humidity of 50 ± 5% for 24 hours. For the purpose of measuring the dimensional stability as a physical property value of the film, the condition adjustment at the maximum measurement temperature was not performed. . The distance between chucks was 10 mm, and the temperature program was a program in which the temperature was maintained at 20 ° C. for 3 minutes, and then the temperature was increased to 270 ° C. at a temperature increase rate of 5 ° C./min. The linear expansion coefficient was calculated from the obtained temperature-test piece length curve as a low temperature side temperature of 30 ° C. and a high temperature side temperature of 250 ° C.

(G) Surface appearance (surface smoothness);
The surface (both surfaces) of the transparent conductive film was visually observed while being applied with various incident angles of light from the fluorescent lamp, and evaluated according to the following criteria.
A: There is no wave or scratch on the surface. There is no cloudiness even when looking at the light up close.
○: Slight swells and scratches are observed on the surface when viewed closely. There is a slight cloudiness when I see light up close.
Δ: Waviness and scratches can be observed on the surface. There is also a cloudiness.
X: Many undulations and scratches can be observed on the surface. There is also a clear cloudiness.

(H) Pencil hardness (surface hardness);
The first hard coat (H1) surface was measured using a pencil “Uni (trade name)” of Mitsubishi Pencil Co., Ltd. under a load of 750 g in accordance with JIS K 5600-5-4.

(Li) Scratch resistance;
A test piece taken with a size of 150 mm in length and 50 mm in width so that the machine direction of the poly (meth) acrylimide resin film is the vertical direction of the test piece, the first hard coat (H1) surface is the surface. Stainless steel plate (10 mm long, 10 mm wide) placed on a JIS L 0849 Gakushin test machine and covered with 4 layers of gauze (Kawamoto Sangyo Co., Ltd. medical type 1 gauze) , Thickness 1 mm) is attached, and the stainless steel plate is set so that the vertical and horizontal surfaces are in contact with the test piece. Rubbing was performed 1000 times under the condition of 1 reciprocation / second. Subsequently, a method (JIS R 3257: 1999) in which the water contact angle of the rubbed portion of the test piece is calculated from the width and height of the water droplet using an automatic contact angle meter “DSA20 (trade name)” manufactured by KRUSS. Reference). When the water contact angle was 100 degrees or more, the test piece was set on the Gakushin Tester again, and the same part was rubbed back and forth 1000 times to repeat the work of measuring the water contact angle. Thus, the number of rubbing required for the water contact angle to be less than 100 degrees was determined as the value of scratch resistance.

Raw materials used (α) Poly (meth) acrylimide resin:
(Α-1) Poly (meth) acrylimide “PLEXIMID TT70 (trade name)” manufactured by Evonik.

(Β) Aromatic polycarbonate resin:
(Β-1) Aromatic polycarbonate “Caliver 301-4 (trade name)” by Sumika Stylon Polycarbonate Co., Ltd.

(Γ) Hard coat forming paint (γ-1)
10 parts by mass of the following component γa, 35 parts by mass of the following component γb, 25 parts by mass of the following component γc, 75 parts by mass of the following component γd, 1.2 parts by mass of the following component γe, 4.0 parts by mass of the following component γg, 1 part of the following component γh 1 It was obtained by mixing and stirring 0.0 parts by mass and 30 parts by mass of the following component γi.
(Γ-2)
10 parts by mass of the following component γa, 35 parts by mass of the following component γb, 25 parts by mass of the following component γc, 75 parts by mass of the following component γd, 0.5 parts by mass of the following component γf, 4.0 parts by mass of the following component γg, 1 part of the following component γh 1 It was obtained by mixing and stirring 0.0 parts by mass and 30 parts by mass of the following component γi.

(Γa) Dipentaerythritol hexaacrylate of Nippon Kayaku Co., Ltd.
(Γb) “A-Toresin H-135 (trade name)”, a mixed paint of urethane acrylate and acrylate oligomer from Negami Kogyo Co., Ltd.
(Γc) Ethoxylated trimethylolpropane triacrylate “NK Ester A-TMPT-3EO (trade name)” of Shin-Nakamura Chemical Co., Ltd.
(Γd) A modified silica 30 mass% dispersion “Art Resin H-135-H02 (trade name)” from Negami Kogyo Co., Ltd.
(Γe) Fluorine-based antifouling additive “KY-1203 (trade name)” from Shin-Etsu Chemical Co., Ltd.
(Γf) Surface conditioning agent “BYK-399 (trade name)” of Big Chemie Japan, Inc.
(Γg) Phenylketone-based photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone) “SB-PI714 (trade name)” of Sojyo Sangyo Co., Ltd.
(Γh) Trifunctional polyisocyanate “Coronate HX (trade name)” by Nippon Polyurethane Industry Co., Ltd.
(Γi) Methyl isobutyl ketone.

(A) Poly (meth) acrylimide resin film (a1) Transparent multilayer film 1:
Using the coextrusion film forming apparatus having the structure shown in FIG. 1, the above (α-1) is used as both outer layers (α1 layer and α2 layer) of the molten film of the transparent multilayer film by the extruder 1, and the above (β-1) As the intermediate layer (β layer) of the melt film of the transparent multilayer film by the extruder 2, α1 layer; β layer; α2 layer; Continuously extruded from the multi-manifold coextrusion T-die 3 and between the rotating mirror surface roll 5 and the mirror belt 6 circulating along the outer peripheral surface of the mirror surface roll so that the α1 layer is on the mirror surface roll 5 side. Supplying and pressing was performed to obtain a transparent multilayer film having a total thickness of 250 μm, an α1 layer thickness of 80 μm, a β layer thickness of 90 μm, and an α2 layer thickness of 80 μm. At this time, the setting condition is that the drying temperature before film formation is (α-1) is 150 ° C and (β-1) is 100 ° C; the setting temperature of the extruder 1 is C1 / C2 / C3 / C4 / C5 / AD = 260 / 290-290 ° C; set temperature of extruder 2 is C1 / C2 / C3 / C4 / C5 / C6 / AD = 260/280/280 / 260-260 / 270 ° C; Perform nitrogen purge and use vacuum vent; T die 3 set temperature 300 ° C., lip opening 0.5 mm; mirror roll 5 set temperature 130 ° C .; mirror belt 6 set temperature 120 ° C., pressure 1.4 MPa; The speed was 6.5 m / min.

(A2) Single layer film of poly (meth) acrylimide resin:
Using (α-1) above, a 50 mm extruder (with a W flight screw of L / D = 29, CR = 1.86); a T die having a die width of 680 mm; pressing a molten film with a mirror roll and a mirror belt A film having a thickness of 250 μm was obtained using an apparatus equipped with a winder equipped with a mechanism for At this time, the setting conditions of the extruder are C1 / C2 / C3 / AD = 280/300/320/320 ° C .; T die setting temperature 320 ° C .; T die lip opening 0.5 mm; Set temperature 140 ° C .; mirror belt set temperature 120 ° C .; mirror belt pressure 1.4 MPa; take-up speed 5.6 m / min.

(A3) Transparent multilayer film 2:
Except for changing the total thickness to 500 μm, α1 layer thickness of 80 μm, β layer thickness of 340 μm, α2 layer thickness of 80 μm, and taking the take-up speed to 3.3 m / min, the same as (a1) above. Thus, a transparent multilayer film was obtained.

(A ′) Comparative transparent resin film base material (a′1) Biaxially stretched polyethylene terephthalate film “Diafoil (trade name)” manufactured by Mitsubishi Plastics Co., Ltd., thickness 250 μm.

(A′2) Acrylic resin film “Technoloy S001G (trade name)” from Sumitomo Chemical Co., Ltd., thickness 250 μm.

(A′3) Using (β-1) above, a 50 mm extruder (with a W flight screw of L / D = 29, CR = 1.86); a T die having a die width of 680 mm; a mirror roll and a mirror belt A film having a thickness of 250 μm was obtained using an apparatus equipped with a drawing winder equipped with a mechanism for pressing the molten film. At this time, the setting conditions of the extruder are C1 / C2 / C3 / AD = 280/300/320/320 ° C .; T die setting temperature 320 ° C .; T die lip opening 0.5 mm; Set temperature 140 ° C .; mirror belt set temperature 120 ° C .; mirror belt pressure 1.4 MPa; take-up speed 5.6 m / min.

Example 1
(B) Hard coat formation:
Corona discharge treatment was performed on both surfaces of the above (a1) under the conditions of a processing amount of 167 W · min / m ² (discharge power 500 W, discharge electrode length 1 m, line speed 3 m / min). The wetness index on both sides was 64 mN / m. Subsequently, the above-mentioned (γ-1) is applied to the surface on the α1 layer side as a touch surface side hard coat layer forming coating using a die type coating apparatus so that the thickness after curing is 25 μm. The surface of the α2 layer side is coated with the above-mentioned (γ-2) as a transparent conductive film forming surface side hard coat layer forming coating, and the thickness after curing is 25 μm using a die-type coating device. Application was conducted to obtain a hard coat laminate.

(C) Formation of transparent conductive film:
The hard coat laminate obtained above is put into a sputtering apparatus, and the pressure is reduced so that the degree of vacuum of the sputtering apparatus is 5 × 10 ⁻⁶ or less. Removed moisture and gas components. Subsequently, a transparent conductive thin film (thickness 28 nm) made of an indium-tin composite oxide was formed on the transparent conductive film forming surface of the hard coat laminate using a direct current magnetron sputtering method. The target was indium oxide containing 10% by mass of tin oxide, the applied DC power was 1.0 kW, the center roll temperature was 23 ° C., and the argon gas partial pressure during sputtering was 0.67 Pa. A small amount of oxygen gas was flowed so that the surface resistivity was minimized, and the partial pressure was 7.5 × 10 ⁻³ Pa. The hard coat laminated body in which the transparent conductive film was formed was taken out from the sputtering apparatus and annealed at 150 ° C. for 60 minutes.

About the transparent conductive film obtained in this way, said (i)-(ri) was evaluated. The results are shown in Table 1.

Example 2
The same procedure as in Example 1 was performed except that (a2) was used instead of (a1). The results are shown in Table 1.

Example 3
The same procedure as in Example 1 was performed except that (a3) was used instead of (a1). The results are shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was performed except that the above (a′1) was used instead of the above (a1). The linear expansion coefficient was not measurable due to significant shrinkage of the film. The results are shown in Table 1.

Comparative Example 2
The same procedure as in Example 1 was performed except that the above (a′2) was used instead of the above (a1). The results are shown in Table 1.

Comparative Example 3
The same procedure as in Example 1 was performed except that the above (a′3) was used instead of the above (a1). The results are shown in Table 1.

The transparent conductive film of the present invention is excellent in transparency, non-colorability, surface resistivity, adhesion of the transparent conductive film, and thermal dimensional stability. Also, the surface appearance, the pencil hardness of the touch surface and the scratch resistance are good. On the other hand, since a film base other than the poly (meth) acrylimide resin film was used, Comparative Example 1 was inferior in total light transmittance and thermal dimensional stability. Comparative Examples 2 and 3 are inferior in thermal dimensional stability and have a higher surface resistivity than the transparent conductive film of the present invention. In either case, the pencil hardness of the touch surface is lower than that of the transparent conductive film of the present invention.

In Example 1 of this invention, (a1) It is a conceptual diagram of the apparatus used for film forming of the transparent multilayer film 1. FIG.

1: Extruder 1
2: Extruder 2
3: Co-extrusion T die of 2 types, 3 layers, multi-manifold system 4: Melted film 5: Mirror roll 6: Mirror belt 7: A pair of belt rollers

Claims (7)

A transparent conductive film, wherein a hard coat and a transparent conductive film are formed in this order on at least one surface of a poly (meth) acrylimide resin film.
The poly (meth) acrylimide resin film is
First poly (meth) acrylimide resin layer (α1);
Aromatic polycarbonate-based resin layer (β);
A second poly (meth) acrylimide resin layer (α2);
The transparent conductive film according to claim 1, which is a transparent multilayer film directly laminated in this order.
The thickness of the said poly (meth) acrylimide-type resin film is 100-1500 micrometers, The transparent conductive film of Claim 1 or 2 characterized by the above-mentioned.
In order from the outermost layer side,
First hard coat (H1);
A layer of a poly (meth) acrylimide resin film;
Second hard coat (H2);
Transparent conductive film;
The transparent conductive film according to claim 1, comprising:
The transparent conductive film according to any one of claims 1 to 4, wherein the transparent conductive film of the transparent conductive film has a surface resistivity of 120Ω / sq or less and a total light transmittance of 85% or more. Sex film
An image display device comprising the transparent conductive film according to claim 1.
Use of the transparent conductive film according to any one of claims 1 to 5 as an image display device member.

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