JP2013111804A - Hard coat film and touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coat film which is highly resistant to sliding caused by a pen or finger and keeps crack generation well under control, as well as a touch panel equipped with the hard coat film.SOLUTION: This hard coat film includes a hard coat layer A formed on one side of a base film and a hard coat layer B on the other side of the base film. The pencil hardness of the hard coat layer A is not less than 2H, and the elongation in tension of the hard coat layer B is not less than 10%.

Description

  The present invention relates to a hard coat film, and more particularly to a hard coat film having a hard coat layer on both sides of a base film and a touch panel provided with the hard coat film.

  The double-sided hard coat film having the hard coat layer on both sides of the base film is used as, for example, a surface protective member for the touch surface of the touch panel (Patent Documents 1 to 4), or the base of the conductive film for forming the upper electrode of the touch panel. It is known to be used as a material film (Patent Documents 5 to 11).

  Since the touch surface of the touch panel is repeatedly pressed with a pen or a finger, as described above, a double-sided hard coat film is used as the surface protective member for the touch surface or the base film of the conductive film for forming the upper electrode.

Japanese Patent Laid-Open No. 8-148036 JP 2002-103504 A JP 2003-80644 A Japanese Patent Application Laid-Open No. 2006-155542 JP 2010-188540 A JP 2011-39978 A JP2011-65937A JP 2011-68064 A JP 2011-145593 A JP 2011-175040 A JP 2011-201087 A

  The touch surface of the touch panel is required to have a hard coat property that can withstand pressing (sliding) with a pen or a finger. Generally, a hard coat film used for the touch surface is provided with a hard coating layer having high hardness.

  However, when a hard coat film with a hard coat layer with high hardness on both sides of the base film is used for the touch surface of the touch panel, the hard coat layer on one side (back side; opposite to the touch surface) cracks. The problem that occurs occurs. This problem cannot be sufficiently solved by the double-sided hard coat film disclosed in the above patent document.

  Accordingly, an object of the present invention is to provide a hard coat film that has excellent sliding resistance with a pen or a finger and suppresses the occurrence of cracks, and a touch panel provided with the hard coat film, in view of the above-described problems of the prior art. There is to do.

The above object of the present invention has been basically achieved by the following invention.
1) A hard coat film having a hard coat layer A on one side of the base film and a hard coat layer B on the other side of the base film, wherein the hard coat layer A has a pencil hardness of 2H or more A hard coat film, wherein the hard coat layer B has a tensile elongation of 10% or more.

2) The base film is a polyethylene terephthalate film having a refractive index (nf) of 1.63 to 1.70, and the polyethylene terephthalate film has a refractive index (np) of 1.54 to 1.61 on both sides. It has an easy adhesion layer, the refractive index (nh) of the hard coat layer A and the hard coat layer B is 1.48 to 1.55, respectively, and both sides of the substrate film are represented by the following formulas 1 to 3 The hard coat film of 1) satisfying all of the above.
nf>np> nh... Formula 1
nf−np <0.1 Formula 2
np-nh <0.1 Formula 3

  3) The hard coat film of 1) or 2), the upper electrode layer, and the lower electrode layer are laminated in this order, and the surface of the hard coat film on the hard coat layer B side is directed to the upper electrode layer side. Touch panel.

  4) An upper electrode is formed by the upper electrode layer and the base material, a lower electrode is formed by the lower electrode layer and the base material, and the surface of the hard coat film on the hard coat layer B side is The touch panel according to 3), which is bonded to the base material of the upper electrode via an adhesive layer.

  5) The upper electrode layer is laminated on the surface of the hard coat film on the hard coat layer B side, and the upper electrode is formed by the hard coat film and the upper electrode layer. The lower electrode layer and the base material The touch panel according to 3), wherein a lower electrode is formed.

  ADVANTAGE OF THE INVENTION According to this invention, the hard coat film which was excellent in the sliding resistance by a pen and a finger | toe, and the generation | occurrence | production of the crack was suppressed can be provided. Moreover, the hard coat film of the present invention is preferably applied to a touch panel.

  According to a preferred embodiment of the present invention, it is possible to provide a hard coat film in which uneven reflection color is further suppressed.

FIG. 1 is a schematic sectional view of a general touch panel provided with a conventional hard coat film or the hard coat film of the present invention. FIG. 2 is a schematic cross-sectional view of another example of a touch panel to which the hard coat film of the present invention is applied. FIG. 3 is a plan view of a glass plate (with double-sided adhesive tape on four sides) used for a sliding resistance test with a pen.

  The hard coat film of the present invention has a hard coat layer A having a pencil hardness of 2H or higher on one side of the base film, and a hard coat layer B having a tensile elongation of 10% or higher on the other side of the base film. Have

  The pencil hardness in the present invention is measured with a load of 750 g in accordance with JIS K5600-5-4 (1999). Further, the tensile elongation in the present invention is an elongation when a crack is generated in the hard coat layer when one side of the hard coat film is fixed and the hard coat film is pulled at a pulling speed of 50 mm / min.

  The hard coat film disclosed in the above-mentioned patent document or the hard coat film for a touch panel generally used conventionally has a relatively high hardness of the hard coat layer and a relatively low tensile elongation (5% The following).

  When the conventional hard coat film provided with such a hard coat layer having a small tensile elongation is arranged on the touch surface of the touch panel as shown in FIG. 1, the touch input operation (sliding) with a pen or the like is repeated. It was found that there was a problem that a crack occurred in the hard coat layer on the side opposite to the touch surface.

  FIG. 1 is a schematic sectional view of a general touch panel provided with a conventional hard coat film or the hard coat film of the present invention. In FIG. 1, a hard coat film 1 is laminated on an upper electrode 21 via an adhesive layer 3 to constitute a touch panel 2. The hard coat film 1 has a hard coat layer 11 on one surface (front surface) of the base film 10 and a hard coat layer 12 on the other surface (back surface).

  In FIG. 1, when the hard coat film 1 is a conventional hard coat film, reference numeral 11 is a front surface hard coat layer, and reference numeral 12 is a back surface hard coat layer. On the other hand, when the hard coat film 1 is the hard coat film of the present invention, the reference numeral 11 is the hard coat layer A, and the reference numeral 12 is the hard coat layer B.

  In FIG. 1, when the touch input operation (sliding) is repeatedly performed with the pen 4, when the conventional hard coat film is used, a crack occurs in the back surface hard coat layer 12. This is because when the touch panel 2 presses the surface of the hard coat layer 11 on the surface of the hard coat film 1 with the pen 4 because a gap exists between the upper electrode 21 and the lower electrode 22 (a gap is formed by the insulating spacer 27). The back surface hard coat layer 12 is curved outward (opposite side of the base film 10), and cracks are generated in the back surface hard coat layer 12 by repeating this curvature.

  When the pen is pressed, the outward bending of the back surface hard coat layer 12 has a relatively thick adhesive layer on the lower side (touch panel side) of the hard coat film 1 in addition to the presence of voids. Can also happen.

  The present invention has found that the occurrence of cracks in the back side hard coat layer 12 is suppressed by setting the tensile elongation of the hard coat layer to 10% or more. On the other hand, the surface hard coat layer 11 is required to have sliding resistance capable of withstanding touch input (sliding) with a pen or the like, and the pencil hardness of the hard coat layer is found to be 2H or more.

  That is, in FIG. 1, a hard coat layer A (11) having a pencil hardness of 2H or more is provided on one surface of the base film 10, and a hard elongation having a tensile elongation of 10% or more is provided on the other surface of the base film 10. By mounting the hard coat film 1 of the present invention having the coat layer B (12) on the touch panel 2, the above-described problems of crack generation and sliding resistance are solved.

  As described above, the hard coat film of the present invention is preferably used on the touch surface side of the touch panel. The preferable aspect is an aspect by which a hard coat film is arrange | positioned so that the surface by the side of the hard coat layer B of a hard coat film may face the upper electrode layer side of a touch panel.

  One aspect of the above is the above-described aspect of FIG. That is, the surface of the hard coat film 1 of the present invention on the hard coat layer B (12) side is bonded to the base material 23 of the upper electrode 21 composed of the base material 23 and the upper electrode layer 24 with the adhesive layer 3 interposed therebetween. It is the aspect which is.

  In FIG. 1, the touch panel 2 has an upper electrode 21 and a lower electrode 22 arranged via an insulating spacer 27, the upper electrode 21 includes a base material 23 and an upper electrode layer 24, and the lower electrode 22 The lower electrode layer 26 is formed.

  Another preferred embodiment is the embodiment shown in FIG. In this embodiment, the hard coat film of the present invention is used as the base material of the upper electrode 21. That is, the upper electrode layer 24 is laminated on the surface of the hard coat film 1 on the hard coat layer B (12) side, and the upper electrode 21 is formed by the hard coat film 1 and the upper electrode layer 24.

  1 and FIG. 2 is, in other words, the hard coat layer A (11) of the hard coat film 1 of the present invention with respect to the upper electrode layer 24 of the touch panel 2 and the touch side (the pen 4 side in the drawing). It is the aspect arrange | positioned so that it may become.

  The upper electrode layer 24 of the upper electrode 21 and the lower electrode layer 26 of the lower electrode 22 constituting the touch panel 2 are generally made of tin oxide, indium oxide, antimony oxide, zinc oxide, ITO (indium tin oxide), ATO (antimony tin oxide). It is a transparent conductive film formed on a base material (23, 25) by vapor phase film forming method such as sputtering or vacuum deposition.

[Hard coat film]
Hereinafter, the hard coat film of the present invention will be described in detail. The hard coat film of the present invention has a hard coat layer A having a pencil hardness of 2H or higher on one side of the base film, and a hard coat layer B having a crack elongation of 10% or higher on the other side of the base film. Have

[Base film]
A plastic film is preferably used as the substrate film. Although it does not specifically limit as resin which comprises a plastic film, For example, polyester resin (For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate etc.), polymethylmethacrylate resin, acrylic resin, polycarbonate resin, polystyrene resin , Triacetyl cellulose resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyethylene resin, ethylene-vinyl acetate copolymer resin, polyvinyl butyral resin, metal ion crosslinked ethylene-methacrylic acid copolymer resin, polyurethane resin Etc. Among these, a polyester resin is preferable from the viewpoint of high resistance to heat and solvent and high transparency, and polyethylene terephthalate is preferably used from the viewpoint of processability.

The thickness of the base film is preferably in the range of 20 to 250 μm, and more preferably in the range of 50 to 200 μm.
The refractive index (nf) of the polyethylene terephthalate film preferably used in the present invention is generally in the range of 1.63-1.70, and preferably in the range of 1.64-1.68.

  In the case of using a polyethylene terephthalate film as the base film, it is preferable to use a polyethylene terephthalate film having an easy-adhesion layer on both sides from the viewpoint of enhancing the adhesion to the hard coat layer laminated on both sides.

  It is preferable that an easily bonding layer has a resin component and a crosslinking agent as a main component. Examples of the resin component include polyester resin, acrylic resin, and urethane resin, and examples of the crosslinking agent include melamine crosslinking agent, oxazoline crosslinking agent, carbodiimide crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, and epoxy crosslinking agent. Is mentioned. Among the resin components, a polyester resin is preferably used from the viewpoint of adjusting the refractive index of the easy-adhesion layer to a range described later.

  The easy-adhesion layer preferably contains inorganic fine particles to further improve the slipperiness. Colloidal silica is preferably used as the inorganic fine particles.

  The thickness of the easy-adhesion layer is preferably in the range of 10 to 300 nm, more preferably in the range of 20 to 250 nm, and particularly preferably in the range of 30 to 200 nm.

  In addition, when a polyethylene terephthalate film is used as the base film of the hard coat film of the present invention, from the viewpoint of suppressing uneven reflection color of the hard coat film, the refractive index of the easy adhesion layer provided on both surfaces of the polyethylene terephthalate film ( np) is preferably in the range of 1.54 to 1.61, more preferably in the range of 1.55 to 1.60, and particularly preferably in the range of 1.56 to 1.59.

Furthermore, from the viewpoint of suppressing the reflection color unevenness of the hard coat film, it is preferable that both surfaces of the base film satisfy all of the following formulas 1 to 3.
nf>np> nh... Formula 1
nf−np <0.1 Formula 2
np-nh <0.1 Formula 3
In the above formulas 1 to 3, nf is the refractive index of the base film, np is the refractive index of the easy adhesion layer, and nh is the refractive index of the hard coat layer A and the hard coat layer B.

  In the above formulas 2 and 3, nf-np and np-nh are more preferably less than 0.09, and particularly preferably less than 0.08.

  Further, the refractive index (nh) of the hard coat layer A and the hard coat layer B of the present invention described later is preferably in the range of 1.48 to 1.55, more preferably in the range of 1.50 to 1.54. In particular, the range of 1.51-1.53 is preferable.

[Hard coat layer A]
The hard coat layer A has a pencil hardness of 2H or more. The refractive index of the hard coat layer A is preferably 3H or more. The upper limit is about 9H.

  The hard coat layer A is a layer obtained by applying a composition for forming a hard coat layer A containing a thermosetting or active energy ray-curable resin by a wet coating method, drying it as necessary, and then curing it. Is preferred. As the composition for forming the hard coat layer A, a composition containing an active energy ray-curable resin is particularly preferable.

  Such an active energy ray-curable resin is a resin that is cured by active energy rays such as ultraviolet rays and electron beams, and a polymerizable compound (for example, a monomer or an oligomer) having an ethylenically unsaturated group in the molecule is preferably used. Here, examples of the ethylenically unsaturated group include an acryl group, a methacryl group, a vinyl group, and an allyl group.

  From the viewpoint of imparting hard coat properties with a pencil hardness of 2H or more to the hard coat layer A, the composition for forming the hard coat layer A preferably contains a compound having three or more ethylenically unsaturated groups in the molecule. In the following description, the expression “... (Meth) acrylate” includes two compounds “... acrylate” and “... methacrylate”.

  Examples of the polymer compound having 3 or more ethylenically unsaturated groups in the molecule include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol tris. (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol tri (meth) acrylate, tripentaerythritol hexa (meth) triacrylate , Pentaerythritol triacrylate hexamethylene diisocyanate urethane pre-oligomer, pentaerythritol triacrylate toluene diisocyanate DOO urethane oligomer, pentaerythritol triacrylate isophorone diisocyanate urethane oligomer and the like.

  The composition for forming a hard coat layer A is a polymer compound having 3 or more ethylenically unsaturated groups in the molecule, and is 30% by mass or more with respect to 100% by mass of the total solid content of the composition for forming the hard coat layer A. It is preferably included, more preferably 40% by mass or more, and particularly preferably 50% by mass or more. The upper limit is preferably 98% by mass or less, and more preferably 95% by mass or less.

  The composition for forming the hard coat layer A can further contain a polymerization compound (for example, a monomer or an oligomer) having 1 to 2 ethylenically unsaturated groups in the molecule. The content of the polymerization compound having 1 to 2 ethylenically unsaturated groups in the molecule is preferably 30% by mass or less with respect to 100% by mass of the total solid content of the composition for forming the hard coat layer A.

  Examples of the polymer compound having one ethylenically unsaturated group in the molecule include methyl (meth) acrylate, lauryl (meth) acrylate, ethyldiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, and methoxytriethylene glycol. (Meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, isobornyloxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, 2-hydroxy-3-phenoxy (meth) acrylate, 2-ethylhexyl (meth) acrylate, acrylamide, (meth) acryloylmorpholine, -Amino-3,7-dimethyloctyl (meth) acrylate, isobutoxymethyl (meth) acrylamide, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate Etc.

  Examples of the polymer compound having two ethylenically unsaturated groups in the molecule include neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, and propylene. Glycol di (meth) acrylate, tripropylene glycol diacrylate, 1,4-butanediol di (meth) acrylate, 2-hydroxyethyl di (meth) acrylate, 1-hydroxypropyl di (meth) acrylate, 1-hydroxybutyl di (Meth) acrylate, 4-hydroxybutyl di (meth) acrylate, 2-hydroxypentyl di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate Over doors and the like.

  It is preferable that the composition for forming the hard coat layer A contains a photopolymerization initiator. Examples of the photopolymerization initiator include isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler ketone, o-benzoylmethyl benzoate, acetophenone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, ethyl anthraquinone, p-dimethylaminobenzoic acid. Isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethane 1-one, 2-benzyl-2-dimethylamino-1 (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, Jiruhorumeto and the like.

Moreover, generally the photoinitiator is marketed and they can be used. For example,
Irgacure 907, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 500, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870, Irgacure OXE01, DAROCUR RP SPEEDCURE MBB, SPEEDCURE PBZ, SPEEDCURE ITX, SPEEDCURE CTX, SPEEDCURE EDB, Escure ONE, Esacure KIP150, Esacure KTO46, etc. And the like.

  The content of the photopolymerization initiator is suitably in the range of 0.1 to 10% by mass and in the range of 0.5 to 8% by mass with respect to 100% by mass of the total solid content of the composition for forming the hard coat layer A. Is preferred.

  The composition for forming the hard coat layer A can further contain an ultraviolet absorber, an antioxidant, a light stabilizer, inorganic particles, organic particles, a lubricant, an antistatic agent, and the like.

  When using especially the hard coat film of this invention for the use of the touch panel mentioned above, it is preferable that a hard-coat layer contains a ultraviolet absorber. As a result, deterioration of the hard coat layer (yellowing, generation of cracks, decrease in adhesion, etc.) due to external light (ultraviolet rays) can be suppressed.

  As such ultraviolet absorbers, triazine ultraviolet absorbers, benzotriazole ultraviolet absorbers, and benzophenone ultraviolet absorbers can be used. Among the above ultraviolet absorbers, the initial adhesion of the hard coat layer A and the adhesion after exposure to ultraviolet rays can be imparted at a high level, and yellowing and cracking of the hard coat layer A after exposure to ultraviolet rays can occur. From the viewpoint of being able to suppress efficiently, a triazine-based ultraviolet absorber is preferable, and a hydroxyphenyl triazine-based ultraviolet absorber is particularly preferably used.

Examples of the hydroxyphenyltriazine-based ultraviolet absorber preferably used in the present invention are shown below.
2,4-bis (2-hydroxy-4-butyroxyphenyl) -6- (2,4-bis-butyroxyphenyl) -1,3,5-triazine,
2,4-bis ((4- (2-ethyl-hexyloxy) -2-hydroxy) -phenyl))-6- (4-methoxyphenyl) -1,3,5-triazine,
2,4-bis (2,4-dihydroxyphenyl) -6- (4-methoxyphenyl) -1,3,5-triazine,
2,4-bis ((4- (3- (2-propyloxy) -2-hydroxy-propyloxy) -2-hydroxy) -phenyl) -6- (4-methoxyphenyl) -1,3,5- Triazine,
2,4-bis (2-hydroxy-4-octoxyphenyl-6- (2,4-dimethylphenyl) -1,3,5-triazine,
2,4-bis (2-hydroxy-4-propyloxyphenyl) -6- (2,4-dimethylphenyl) -1,3,5-triazine,
2-phenyl-4,6-bis (2-hydroxy-4- (3 ′-(methoxyheptaethoxy) -2′-hydroxypropoxy) -phenyl) -1,3,5-triazine,
2-phenyl-4,6-bis (2-hydroxy-4-((methoxytriethoxycarbonyl) -2-ethoxy) -phenyl) -1,3,5-triazine,
2- (4′-methoxyphenyl) -4,6-bis (2′-hydroxy-4′-n-octyloxyphenyl) -1,3,5-triazine.

  The content of the ultraviolet absorber is preferably in the range of 0.5 to 8% by mass, more preferably in the range of 1 to 7% by mass, particularly preferably 1.5 to 7% by mass with respect to 100% by mass of the solid content of the hard coat layer A. A range of 5% by mass is preferred.

  The thickness of the hard coat layer A is preferably in the range of 1 to 20 μm, more preferably in the range of 2 to 15 μm, and particularly preferably in the range of 3 to 10 μm.

  Examples of the coating method used when wet-coating the composition for forming the hard coat layer A include, for example, a reverse coating method, a spray coating method, a bar coating method, a gravure coating method, a rod coating method, a die coating method, a spin coating method, and an extensible method. Examples include the rouge coating method.

[Hard coat layer B]
The hard coat layer B has a tensile elongation of 10% or more. The tensile elongation of the hard coat layer B is preferably 15% or more, more preferably 20% or more, and particularly preferably 25% or more. The upper limit is preferably 150% or less, more preferably 100% or less, further preferably 80% or less, and particularly preferably 60% or less.

  When the tensile elongation of the hard coat layer B is less than 10%, cracks are likely to occur due to sliding with a pen or a finger, while when the tensile elongation exceeds 150%, the pencil hardness decreases, The hard coat layer B may be damaged by sliding with a finger or the like or in a processing step.

  The hard coat layer B is a layer obtained by applying a composition for forming a hard coat layer B containing a thermosetting or active energy ray-curable resin by a wet coating method, drying it as necessary, and then curing it. Is preferred. As the composition for forming the hard coat layer B, a composition containing an active energy ray-curable resin is particularly preferable.

  Such an active energy ray-curable resin is a resin that is cured by active energy rays such as ultraviolet rays and electron beams, and a polymerizable compound (for example, a monomer or an oligomer) having an ethylenically unsaturated group in the molecule is preferably used. Here, examples of the ethylenically unsaturated group include an acryl group, a methacryl group, a vinyl group, and an allyl group.

  From the viewpoint of providing the hard coat layer B with a tensile elongation of 10% or more, the composition for forming the hard coat layer B is preferably the following composition 1 or composition 2.

(Composition 1)
Composition 1 comprises a polymerizable compound (a) having 1 to 2 ethylenically unsaturated groups in the molecule and a polymerizable compound (b) having 3 or more ethylenically unsaturated groups in the molecule. It is a composition containing 10 to 90% by mass of the polymerizable compound (a) and 3 to 60% by mass of the polymerizable compound (b) with respect to 100% by mass of the total solid content of 1. Preferably, it is a composition containing 20 to 80% by mass of the polymerizable compound (a) and 5 to 50% by mass of the polymerizable compound (b) with respect to 100% by mass of the total solid content of the composition 1.

  The polymerizable compound (a) having 1 to 2 ethylenically unsaturated groups in the molecule and the polymerizable compound (b) having 3 or more ethylenically unsaturated groups in the molecule are for forming the hard coat layer A described above. A compound similar to the compound that can be used in the composition can be used.

  Composition 1 preferably further contains a photopolymerization initiator. As a photoinitiator, the thing similar to what is used for the above-mentioned composition for hard-coat layer A formation can be used. The content of the photopolymerization initiator is suitably in the range of 0.1 to 10% by mass and preferably in the range of 0.5 to 8% by mass with respect to 100% by mass of the total solid content of the composition 1.

(Composition 2)
The composition 2 is a composition containing 30 to 90% by mass of a urethane (meth) acrylate monomer or oligomer having an ethylenically unsaturated group in the molecule with respect to 100% by mass of the total solid content of the composition 2.

  Specific examples of the urethane (meth) acrylate monomer or oligomer include AT-600, UA-101l, UA-306H, UA-306T, UA-306l, UF-8001, and UF-8003 manufactured by Kyoeisha Chemical Co., Ltd. Such as UV7550B, UV-7600B, UV-1700B, UV-6300B, UV-7605B, UV-7640B, UV-7650B manufactured by Nippon Synthetic Chemical Co., Ltd. U-4HA, U-6HA, UA manufactured by Shin-Nakamura Chemical Co., Ltd. -100H, U-6LPA, U-15HA, UA-32P, U-324A, U-2PPA, UA-NDP, etc., Daicel UCB, Inc. Ebecryl-1290, Ebecryl-12 0K, etc. Ebecryl-5129, Negami Chemical Industrial Co., Ltd. of UN-3220HA, UN-3220HB, UN-3220HC, UN-3220HS, etc., manufactured by Mitsubishi Rayon Co., Ltd. of the RQ series, Arakawa Chemical Industry Co., Ltd. of beam set series, and the like.

  The composition 2 can further contain a polymerizable compound (b) having 3 or more ethylenically unsaturated groups in the molecule. The content of the polymerizable compound (b) is preferably in the range of 1 to 30% by mass with respect to 100% by mass of the total solid content of the composition 2.

  The composition 2 preferably further contains a photopolymerization initiator. As a photoinitiator, the thing similar to what is used for the above-mentioned composition for hard-coat layer A formation can be used. The content of the photopolymerization initiator is suitably in the range of 0.1 to 10% by mass, and preferably in the range of 0.5 to 8% by mass with respect to 100% by mass of the total solid content of the composition 2.

  The composition for forming the hard coat layer B can further contain an ultraviolet absorber, an antioxidant, a light stabilizer, inorganic particles, organic particles, a lubricant, an antistatic agent, and the like.

  The thickness of the hard coat layer B is preferably in the range of 0.5 to 10 μm, more preferably in the range of 1 to 8 μm, and particularly preferably in the range of 2 to 6 μm.

  The pencil hardness of the hard coat layer B is preferably F or higher, and more preferably H or higher. The upper limit is preferably 3H or less, and more preferably 2H or less.

  As an application method used when wet-coating the composition for forming the hard coat layer B, the same application method as used for wet coating of the composition for forming the hard coat layer A can be used.

[Other functional layers]
In the hard coat film of the present invention, functional layers such as an antireflection layer, an antiglare layer, an antifouling layer, and an easy slip layer may be laminated on the hard coat layer A and / or the hard coat layer B.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method and evaluation method in an Example are shown below.

(1) Pencil hardness About the hard-coat layer A surface and the hard-coat layer B surface of the hard coat film produced by the Example and the comparative example, it measured based on JISK5600-5-4 (1999), respectively. The load is 750 g, and the speed is 30 mm / min. As the measuring device, a surface hardness tester (HEIDON; type 14DR) manufactured by Shinto Kagaku Co., Ltd. was used. The environment at the time of measurement is 23 ° C. ± 2 ° C. and relative humidity 55% ± 5%.

(2) Tensile elongation of hard coat layer B In Examples and Comparative Examples, an intermediate-stage hard coat film in which only hard coat layer B was laminated was stored at room temperature for 1 day, and then cut into a short form having a length of 110 mm and a width of 20 mm. A test sample was prepared. Using a tensile tester (“Autograph AGS-500NX” manufactured by Shimadzu Corporation), a tensile test was performed while visually confirming the crack occurrence state of the hard coat layer B at a chuck distance of 50 mm and a tensile speed of 50 mm / min. went. The elongation when the crack occurred was defined as the tensile elongation. Each was measured 5 times and averaged. The environment at the time of measurement is 23 ° C. ± 2 ° C. and relative humidity 55% ± 5%.

(3) Sliding test using a pen As shown in FIG. 3, a double-sided adhesive sheet 32 having a thickness of 250 μm and a width of 10 mm is bonded to four sides of a rectangular glass plate (65 mm × 45 mm) 31 having a thickness of 2 mm. A rectangular cut sheet (65 mm × 45 mm) of the hard coat film produced in the examples and comparative examples was bonded to the double-coated pressure-sensitive adhesive sheet of the glass plate, and a test sample was produced.

The above test sample is mounted on a touch panel sliding tester (GRAPHPHEP PENPLOTTER FP3800) manufactured by Touch Panel Laboratories Co., Ltd., and a hemispherical polyacetal resin touch pen with a radius of 0.8 mm R is brought into contact with the hard coat layer A surface. Then, after reciprocating the straight line 40 mm 50,000 times at a load of 250 g and a pen sliding speed of 300 mm / sec, the state of the hard coat layer A and the hard coat layer B of the test sample was observed and evaluated according to the following criteria: . The environment at the time of measurement is 23 ° C. ± 2 ° C. and relative humidity 55% ± 5%.
<Evaluation of hard coat layer A>
○: Scratches are not observed.
X: Scratches are generated.
<Evaluation of hard coat layer B>
○: No cracks are observed.
X: Cracks are generated.

(4) Visual evaluation of reflection color unevenness of hard coat film As shown in FIG. 1, the hard coat films of Examples and Comparative Examples are attached to a touch panel, and the reflection color unevenness is visually observed under a dark room three-wavelength fluorescent lamp. Observed and evaluated according to the following criteria.
○: The occurrence of uneven reflection color is small and does not cause a practical problem.
X: There is a reflection color unevenness, which may cause a practical problem.

(5) Refractive index measurement 1
The refractive indexes of the hard coat layer A, the hard coat layer B, and the easy-adhesion layer are 25 ° C. with respect to a coating film (dry thickness of about 2 μm) obtained by coating the layer forming composition on a silicon wafer with a spin coater. The refractive index of 633 nm was measured with a phase difference measuring device (Nikon Corp .: NPDM-1000) under the temperature conditions.

(6) Refractive index measurement 2 (refractive index of substrate film)
The refractive index of the base film (PET film) was measured with an Abbe refractometer according to JIS K7105 (1981).

Example 1
A hard coat film was prepared in the following manner.
<Base film>
On both sides of a polyethylene terephthalate film (PET film) having a refractive index of 1.65 and a thickness of 125 μm, the following easy-adhesion layer-forming composition 1 is laminated so that the dry thickness is 90 nm. A PET film having an adhesive layer was prepared.

<Composition 1 for easily bonding layer formation>
75 parts by mass of an aqueous polyester resin solution obtained by polycondensation of terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid / ethylene glycol / 1,4-butanediol at 30/15/5/30/20 (mol%) ( Solid content), 20 parts by mass (solid content) of “Nikalac MW12LF” manufactured by Sanwa Chemical as the melamine-based crosslinking agent, 5 mass parts (solid content) of “Epocross WS500” manufactured by Nippon Shokubai as the oxazoline-based crosslinking agent, average particle diameter An aqueous composition was prepared by mixing 0.2 parts by mass (solid content) of 80 nm colloidal silica. The refractive index of this composition was 1.58.

<Preparation of hard coat film>
The following composition 1 for forming a hard coat layer B was applied to one surface of the PET film with a gravure coater, dried with hot air at 90 ° C., and then irradiated with ultraviolet rays (accumulated light amount 400 mJ / cm ² ). A 3 μm hard coat layer B was formed.

Next, on the surface opposite to the surface on which the hard coat layer B of the PET film was laminated, the following composition 1 for forming a hard coat layer A was applied with a gravure coater, dried with hot air at 90 ° C., and then irradiated with ultraviolet rays ( The hard coat layer A having a thickness of 5 μm was formed by irradiating an integrated light amount of 400 mJ / cm ² ), and the hard coat film of Example 1 was obtained.

<Composition 1 for forming hard coat layer B>
As the composition 1 for forming the hard coat layer B, a UV curable hard coating agent “Beam Set 1200H” manufactured by Arakawa Chemical Industries, Ltd. was used. The refractive index of this composition was 1.51.

<Composition 1 for forming hard coat layer A>
As active energy ray-curable resin, 50 parts by mass of dipentaerythritol hexaacrylate and urethane acrylate oligomer (50 parts by mass of “Art Resin UN901T” manufactured by Negami Kogyo Co., Ltd.), photopolymerization initiator (Ciba Specialty Chemicals Co., Ltd.) ) "Irgacure (registered trademark) 184") 5 parts by mass, 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-bis-buty) as a hydroxyphenyltriazine-based ultraviolet absorber Roxyphenyl) -1,3,5-triazine is a composition obtained by dispersing or dissolving 2.5 parts by mass in an organic solvent, and the refractive index of this composition is 1.51.

(Example 2)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 2 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 2 for forming hard coat layer B>
As the hard coat layer B forming composition 2, a UV curable hard coating agent “Beam Set 1470” manufactured by Arakawa Chemical Industries, Ltd. was used. The refractive index of this composition was 1.51.

(Example 3)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 3 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 3 for forming hard coat layer B>
As the composition 3 for forming the hard coat layer B, a UV curable hard coating agent “Beam Set 1200” manufactured by Arakawa Chemical Industries, Ltd. was used. The refractive index of this composition was 1.51.

Example 4
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 4 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 4 for forming hard coat layer B>
As active energy ray curable resin, 33 parts by mass of tripropylene glycol diacrylate, 33 parts by mass of dimethylaminoethyl methacrylate, 36 parts by mass of pentaerythritol triacrylate, photopolymerization initiator (“Irgacure (registered by Ciba Specialty Chemicals) (Trademark) 184 ") 5 parts by mass dispersed or dissolved in an organic solvent. The refractive index of this composition was 1.51.

(Example 5)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 5 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 5 for forming hard coat layer B>
10 parts by mass of dipentaerythritol hexaacrylate is added to 100 parts by mass of the solid content of the UV curable hard coating agent “Beam Set 1200” manufactured by Arakawa Chemical Industries, Ltd. to form composition 5 for forming hard coat layer B Was prepared. The refractive index of this composition was 1.51.

(Example 6)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer A was changed to the following composition 2 for forming a hard coat layer A in the formation of the hard coat layer A.
<Composition 2 for forming hard coat layer A>
2,4-bis (2-hydroxy-4-buty) as a hydroxyphenyltriazine-based UV absorber with respect to 100 parts by mass of the solid content of acrylic hard coat agent “KAYANOVA FOP-1700” manufactured by Nippon Kayaku Co., Ltd. Roxyphenyl) -6- (2,4-bis-butyroxyphenyl) -1,3,5-triazine (2.5 parts by mass) was added to prepare composition 2 for forming hard coat layer A. The refractive index of this composition was 1.51.

(Comparative Example 1)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 6 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 6 for forming hard coat layer B>
As active energy ray-curable resin, 50 parts by mass of dipentaerythritol hexaacrylate and urethane acrylate oligomer (“Art Resin UN901T” manufactured by Negami Kogyo Co., Ltd.), 50 parts by mass, photopolymerization initiator (Ciba Specialty Chemicals ( ("Irgacure (registered trademark) 184"), 5 parts by mass, dispersed or dissolved in an organic solvent. The refractive index of this composition was 1.51.

(Comparative Example 2)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 7 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 7 for forming hard coat layer B>
As the hard coat layer B forming composition 6, an acrylic hard coat agent “KAYANOVA FOP-1700” manufactured by Nippon Kayaku Co., Ltd. was used. The refractive index of this composition was 1.51.

(Comparative Example 3)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer B was changed to the following composition 8 for forming a hard coat layer B in the formation of the hard coat layer B.
<Composition 7 for forming hard coat layer B>
Composition in which 100 parts by mass of pentaerythritol triacrylate as an active energy ray-curable resin and 5 parts by mass of a photopolymerization initiator (“Irgacure (registered trademark) 184” manufactured by Ciba Specialty Chemicals) are dispersed or dissolved in an organic solvent. It is a thing. The refractive index of this composition was 1.51.

(Comparative Example 4)
A hard coat film was produced in the same manner as in Example 1 except that the hard coat layer A was changed to the following composition 3 for forming a hard coat layer A in the formation of the hard coat layer A.
<Composition 3 for forming hard coat layer A>
As the hard coat layer A forming composition 3, a UV curable hard coating agent “Beam Set 1470” manufactured by Arakawa Chemical Industries, Ltd. was used. The refractive index of this composition was 1.51.

(Comparative Example 5)
A hard coat film was produced in the same manner as in Comparative Example 1 except that the following base film was used.
<Base film>
On both sides of a polyethylene terephthalate film (PET film) having a refractive index of 1.65 and a thickness of 125 μm, the following easy-adhesion layer-forming composition 2 is laminated so as to have a dry thickness of 90 nm. A PET film having an adhesive layer was prepared.
<Composition 1 for easily bonding layer formation>
75 parts by mass (solid content) of an aqueous acrylic resin solution obtained by copolymerizing methyl methacrylate / ethyl acrylate / acrylic acid / N-methylolacrylamide at 63/35/1/1 (mass ratio), and Sanwa as a melamine crosslinking agent 20 parts by mass of “Nicarak MW12LF” manufactured by Chemical, 5 parts by mass (solids) of “Epocross WS500” manufactured by Nippon Shokubai as an oxazoline-based crosslinking agent, 0.2 parts by mass of colloidal silica having an average particle size of 80 nm ( A solid composition was mixed to prepare an aqueous composition. The refractive index of this composition was 1.52.

<Evaluation>
About the hard coat film produced by the Example and the comparative example, pencil hardness, tensile elongation, the slidability test by pen, and reflective color nonuniformity were evaluated. The results are shown in Table 1.

  In any of the examples of the present invention, the hard coat layer A is free from scratches in the sliding test with a pen, the hard coat layer B is free from cracks, and there is no occurrence of uneven reflection color.

  On the other hand, in Comparative Examples 1 to 3 and 5, the tensile elongation of the hard coat layer B is less than 10%, and cracks are generated in the sliding test of the hard coat layer B with a pen. Further, in Comparative Example 5, since the relationship between the refractive indexes of the base film, the easy-adhesion layer, and the hard coat layers A and B does not satisfy the above-described formula 2, occurrence of reflected color unevenness is recognized.

  In Comparative Example 4, the pencil hardness of the hard coat layer B is less than 2H, and scratches are generated in the slidability test with the pen of the hard coat layer A.

DESCRIPTION OF SYMBOLS 1 Hard coat film 2 Touch panel 3 Adhesive layer 4 Pen 10 Base film 11 Hard coat layer A (mode of this invention), surface hard coat layer (in the case of a prior art)
12 Hard coat layer B (aspect of the present invention), back hard coat layer (in the case of the prior art)
DESCRIPTION OF SYMBOLS 21 Upper electrode 22 Lower electrode 23 Upper electrode base material 24 Upper electrode upper electrode layer 25 Lower electrode base material 26 Lower electrode lower electrode layer 27 Insulating spacer 31 Glass plate 32 Double-sided adhesive tape

Claims (5)

  A hard coat film having a hard coat layer A on one side of the base film and a hard coat layer B on the other side of the base film, wherein the hard coat layer A has a pencil hardness of 2H or more. A hard coat film, wherein the hard coat layer B has a tensile elongation of 10% or more. The base film is a polyethylene terephthalate film having a refractive index (nf) of 1.63 to 1.70, and the polyethylene terephthalate film has an easy adhesion having a refractive index (np) of 1.54 to 1.61 on both surfaces. The refractive index (nh) of the hard coat layer A and the hard coat layer B is 1.48 to 1.55, respectively, and both of the base film are all of the following formulas 1 to 3 The hard coat film according to claim 1, wherein
nf>np> nh... Formula 1
nf−np <0.1 Formula 2
np-nh <0.1 Formula 3 The hard coat film of claim 1 or 2, an upper electrode layer, and a lower electrode layer are laminated in this order,
A touch panel in which a surface of the hard coat film on the hard coat layer B side is directed to the upper electrode layer side. An upper electrode is formed of the upper electrode layer and the base material,
A lower electrode is formed by the lower electrode layer and the base material,
The touch panel according to claim 3, wherein a surface of the hard coat film on the hard coat layer B side is bonded to the base material of the upper electrode via an adhesive layer. The upper electrode layer is laminated on the surface of the hard coat film on the hard coat layer B side, and an upper electrode is formed with the hard coat film and the upper electrode layer,
The touch panel according to claim 3, wherein a lower electrode is formed by the lower electrode layer and the base material.

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