JP2011175040A - Hard coat film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film for a touch panel, with which the color tone of a display screen is made neutral. <P>SOLUTION: In the hard coat film 1 for a touch panel, a transparent electrode layer 5 is formed on the rear surface side of a polyester film 2. The hard coat film 1 is characterized in that it has a hard coat layer 3 containing a pigment and having a chromaticity adjustment function at least on one surface of the front and rear surfaces of the polyester film 2, and the chromaticity of transmitted color in an L*a*b* color system is within the following range: -1≤a*≤1 and -2≤b*≤0.8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hard coat film, and more particularly to a hard coat film for a touch panel in which a transparent electrode layer such as ITO is formed on the back side of a polyester film.

  Conventionally, when touched with a finger or drawn with a dedicated pen, the part touches the facing electrode, and a resistive film type touch panel in which a signal is input by energization is reduced in size, weight, thickness, etc. Since it is suitable, it is widely used as an input device for various home appliances and portable terminals.

  A conventional touch panel has, for example, an upper electrode in which a transparent electrode layer such as ITO is formed on a polymer film such as a polyester film on a lower electrode in which a transparent electrode layer is formed on a thick substrate such as glass or plastic. , And are laminated via spacers so that they face each other. When the display surface of the upper electrode is pressed with a finger or a pen, the upper electrode and the lower electrode are brought into contact with each other to be energized and a signal is input.

  The upper electrode is generally provided with a hard coat layer on the surface in order to protect the polymer film of the base material to constitute a hard coat film (see Patent Document 1).

  Since the upper electrode including such a hard coat film is used on the surface of the display screen, it is not desirable that the transmitted color appearance is tinted, and the color tone is required to be almost colorless (neutral).

JP 2006-179010 A JP 2003-151356 A

  However, the upper electrode including the hard coat film in the conventional touch panel sometimes has a color appearance. That is, the transparent electrode layer, for example, the ITO electrode layer is yellowish, and the polyester film and the hard coat layer are also slightly yellowish. Therefore, there is a problem that the color tone of the display screen of the display that has passed through the upper electrode is also yellowish.

  This invention is made | formed in view of the situation as mentioned above, and makes it the subject to provide the hard coat film for touchscreens which can make the color tone of a display screen neutral.

  The present invention is characterized by the following in order to solve the above problems.

  1stly, the hard coat film of this invention is a hard coat film for touchscreens in which a transparent electrode layer is formed in the back surface side of a polyester film, Comprising: A pigment | dye is contained in at least one side among the front and back surfaces of a polyester film. A hard coat layer with a chromaticity adjustment function, and the chromaticity of the transmitted color in the L * a * b * color system is in the range of −1 ≦ a * ≦ 1 and −2 ≦ b * ≦ 0.8 It is characterized by being.

  Second, in the first hard coat film, the dye contained in the hard coat layer with a chromaticity adjusting function has a maximum peak wavelength of absorbance within a wavelength range of 560 to 650 nm in the visible light region. It is characterized by that.

  Thirdly, in the first or second hard coat film, the dye contained in the hard coat layer with a chromaticity adjusting function is selected from phthalocyanine dyes, indigo dyes, azo dyes, and quinone dyes. It is at least one kind.

  Fourth, the hard coat film according to any one of the first to third aspects has a hard coat layer with a chromaticity adjusting function on the surface of the front and back surfaces of the polyester film.

  Fifth, in any one of the first to fourth hard coat films, the front and back surfaces of the polyester film have a hard coat layer, and at least one of them is a hard coat layer with a chromaticity adjusting function. Features.

  According to the first to third inventions described above, a hard coat layer with a chromaticity adjusting function containing a pigment is provided on at least one side of the front and back surfaces of the polyester film, and transmission in the L * a * b * color system. By setting the chromaticity of the color within the range of −1 ≦ a * ≦ 1 and −2 ≦ b * ≦ 0.8, the color tone of the display screen can be made neutral.

  According to the fourth invention, in addition to the effects of the first to third inventions, when a hard coat layer is provided only on the front and back surfaces of the polyester film, this is applied to the hard coat with a chromaticity adjusting function. By using layers, the color of the display screen can be neutral.

  According to the fifth invention, at least one of the hard coat layers on the front and back surfaces of the polyester film is a hard coat layer with a chromaticity adjusting function, in addition to the effects of the first to third inventions. Even when a hard coat layer is required on each of the front and back surfaces in order to ensure the performance of the coat film, the color tone of the display screen can be made neutral.

It is sectional drawing which shows an example of the hard coat film of this invention. (A)-(c) is sectional drawing which shows another example of the hard coat film of this invention.

  Hereinafter, the present invention will be described in detail.

  FIG. 1 is a cross-sectional view showing an example of the hard coat film of the present invention.

  This hard coat film 1 is used for a touch panel, and has a polyester film 2 and a hard coat layer 3 with a chromaticity adjusting function formed on the surface of the front and back surfaces of the polyester film 2. A transparent electrode layer 5 such as ITO is formed on the back surface of the hard coat film 1.

  The hard coat layer 3 with a chromaticity adjustment function contains a pigment and has a hard coat layer 3 with a chromaticity adjustment function, so that the transmitted color in the L * a * b * color system of the hard coat film 1 as a whole. Is in a range of −1 ≦ a * ≦ 1 and −2 ≦ b * ≦ 0.8.

  That is, the transparent electrode layer 5 such as ITO is yellowish, and the polyester film 2 and the hard coat layer 3 with a chromaticity adjusting function excluding the dye and the hard coat layer 4 described later are also slightly yellowish. However, in the present invention, the hard coat layer 3 with a chromaticity adjustment function contains a pigment having such a light absorption characteristic as to cancel the yellowishness so that the chromaticity of the transmitted color is within an appropriate range, and the display screen Can be neutral.

  2A to 2C are cross-sectional views illustrating another example of the hard coat film of the present invention. These hard coat films 1 have either a hard coat layer 3 with a chromaticity adjusting function or a normal hard coat layer 4 on each of the front and back surfaces of the polyester film 2. At least one of them is a hard coat layer 3 with a chromaticity adjusting function. In addition, the hard-coat layer 4 can use the thing of the conventional structure which does not contain a pigment | dye, for example.

  The hard coat film 1 of FIG. 2A has a hard coat layer 4 on the front surface of the polyester film 2 and a hard coat layer 3 with a chromaticity adjusting function on the back surface. A transparent electrode layer 5 is formed on the outer surface of the hard coat layer 3 with a chromaticity adjusting function on the back surface side of the polyester film 2.

  The hard coat film 1 in FIG. 2B has a hard coat layer 3 with a chromaticity adjusting function on the front surface of the polyester film 2 and a hard coat layer 4 on the back surface. A transparent electrode layer 5 is formed on the outer surface of the hard coat layer 4 on the back surface side of the polyester film 2.

  The hard coat film 1 in FIG. 2C has a hard coat layer 3 with a chromaticity adjusting function on the front and back surfaces of the polyester film 2. A transparent electrode layer 5 is formed on the outer surface of the hard coat layer 3 with a chromaticity adjusting function on the back surface side of the polyester film 2.

  In the hard coat film 1 of the present invention as shown in FIGS. 1 and 2, the chromaticity of the transmitted color in the L * a * b * color system is −1 ≦ a * ≦ 1 and −2 ≦ b * ≦. It is in the range of 0.8, preferably in the range of −1 ≦ a * ≦ 1 and −1 ≦ b * ≦ 0.6.

  In this invention, as polyester which forms the polyester film 2, the aromatic polyester obtained from aromatic dicarboxylic acid and glycol can be used, for example.

  As the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid and the like can be used.

  As the glycol, for example, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol and the like can be used.

  Among aromatic polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate are particularly preferable. Moreover, the copolymer polyester of the component illustrated above may be sufficient.

  In order to improve the film winding property during film formation, the transportability of the film when forming the hard coat layer 3 with a chromaticity adjusting function or the hard coat layer 4, the polyester film 2 is used as necessary. Fine particles as a lubricant can be contained.

  Examples of such fine particles include inorganic fine particles such as calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, and zinc oxide, or crosslinked acrylic resin fine particles, crosslinked polystyrene resin fine particles, urea resin fine particles, melamine resin fine particles, and crosslinked particles. Organic fine particles such as silicone resin fine particles can be used.

  Further, the polyester film 2 is provided with other components such as a colorant, an antistatic agent, an ultraviolet absorber, an antioxidant, a lubricant, a catalyst, and other resins within a range that does not impair the transparency. It can be included.

  Although the thickness of the polyester film 2 is not specifically limited, For example, it is 50-250 micrometers.

  The polyester film 2 has a haze of preferably 3% or less, more preferably 1.5% or less. If the haze exceeds 3%, problems such as impaired visibility of the display may occur.

  Further, the polyester film 2 has a thin thickness of, for example, 150 nm or less conventionally used on the surface thereof in order to improve adhesion to the hard coat layer 3 with chromaticity adjusting function or the hard coat layer 4. You may have an easily bonding layer.

  In the present invention, the hard coat layer 3 with a chromaticity adjusting function is a film having a hardness higher than that of the polyester film 2, improves the hardness of the surface of the polyester film 2, prevents scratches due to heavy scratches, The mechanical strength of the coat film 1 is improved.

  The pencil hardness of the hard coat layer 3 with chromaticity adjusting function is preferably H or higher, more preferably 2H or higher. In order to improve the hardness of the hard coat layer 3 with chromaticity adjusting function, a color is obtained using at least one of a reactive curable resin composition, that is, a thermosetting resin composition and an ionizing radiation curable resin composition. It is preferable to form the hard coat layer 3 with a degree adjusting function.

  Examples of the thermosetting resin blended in the thermosetting resin composition include phenol resin, urea resin, diallyl phthalate resin, melamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, silicon resin, poly A siloxane resin or the like can be used.

  If necessary, for example, a crosslinking agent, a polymerization initiator, a curing agent, a curing accelerator, and a solvent can be blended with the thermosetting resin composition.

  When forming the hard coat layer 3 with a chromaticity adjusting function using a thermosetting resin composition, the thermosetting resin composition is applied to the front or back surface of the polyester film 2 and then dried and cured by heating. Is preferred.

  As the resin component to be blended in the ionizing radiation curable resin composition, a compound having an acrylate functional group is preferably used. Examples of the compound having an acrylate functional group include, for example, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and polyvalent resins. Polyfunctional (meth) acrylate oligomers such as alcohol resins, prepolymers, and the like can be used. In the present specification, (meth) acrylate means acrylate or methacrylate.

  Moreover, the monomer as a reactive diluent can be mix | blended with said ionizing radiation curable resin composition with said oligomer and prepolymer. Examples of such monomers include monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, trimethylolpropane tri (meth) acrylate, hexanediol ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neo Polyfunctional monomers such as pentyl glycol di (meth) acrylate can be used.

  Further, when the ionizing radiation curable resin composition is an ultraviolet curable resin composition, it is preferable to add a photopolymerization initiator. As the photopolymerization initiator, for example, acetophenones, benzophenones, α-amyloxime esters, thioxanthones and the like can be used.

  Moreover, you may use a photosensitizer with a photoinitiator. As the photosensitizer, for example, n-butylamine, triethylamine, tri-n-butylphosphine, thioxanthone, or the like can be used.

  When forming the hard coat layer 3 with a chromaticity adjusting function using an ultraviolet curable resin composition that undergoes a photopolymerization reaction, for example, the ultraviolet curable resin composition is applied to the front or back surface of the polyester film 2 and dried. And then cured by ultraviolet irradiation.

  The hard coat layer 3 with a chromaticity adjustment function preferably has a refractive index that is close to that of the polyester film 2 in consideration of the reduction in reflectance, and the refractive index of the hard coat layer 3 with a chromaticity adjustment function is preferably Is 1.40 to 1.60.

  The thickness of the hard coat layer 3 with a chromaticity adjusting function is, for example, 1 to 10 μm from the viewpoint of obtaining sufficient mechanical strength.

  The hard coat layer 3 with a chromaticity adjusting function contains a dye. This pigment is adjusted so that the chromaticity of the transmitted color in the L * a * b * color system of the hard coat film 1 is in the range of −1 ≦ a * ≦ 1, −2 ≦ b * ≦ 0.8. The above amount is added to the reactive curable resin composition for forming the hard coat layer 3 with chromaticity adjusting function.

  As a pigment | dye contained in the hard-coat layer 3 with a chromaticity adjustment function, what has the maximum peak wavelength of a light absorbency within the range of wavelength 560-650 nm in visible region can be used, for example. Further, considering the material of the hard coat layer 3 with chromaticity adjusting function, specifically, phthalocyanine dyes such as Cu, Fe, H-phthalocyanine, indigo dyes, azo dyes, quinone dyes and the like are used as the dyes. Can be used.

  Further, in order to increase the refractive index of the hard coat layer 3 with chromaticity adjusting function, the hard coat layer 3 with chromaticity adjusting function contains high refractive index particles, that is, ultrafine particles of high refractive index metal oxide. Can be made. As the high refractive index particles, for example, particles having a refractive index of 1.6 or more and a particle size of 0.5 to 200 nm can be used.

Examples of the ultrafine particles of the high refractive index metal oxide include, for example, particles of at least one oxide selected from zinc, titanium, aluminum, cerium, yttrium, lanthanum, zirconium, tin, indium, antimony, and niobium. Can be used. Specifically, for example, ZnO (refractive index 1.90), TiO ₂ (refractive index 2.3 to 2.7), Al ₂ O ₃ (refractive index 1.63), CeO ₂ (refractive index 1.95). ), Y ₂ O ₃ (refractive index 1.87), La ₂ O ₃ (refractive index 1.95), ZrO ₂ (refractive index 2.05), SnO ₂ , ITO (indium / tin oxide: refractive index 1) .95), Sb ₂ O ₅ (refractive index 1.71), Nb ₂ O ₅ (refractive index 2.2 to 2.3) and other ultrafine particles can be used.

  It is preferable to impart antistatic properties to the hard coat layer 3 with a chromaticity adjusting function, and to ensure antistatic properties and dust adhesion preventing properties as the hard coat film 1. In order to impart antistatic properties to the hard coat layer 3 with a chromaticity adjustment function, for example, conductive nanoparticles can be contained in the hard coat layer 3 with a chromaticity adjustment function.

As the conductive nanoparticles, for example, ultrafine particles of conductive metal oxide having a particle size of 0.5 to 200 nm can be used. Specifically, for example, particles of at least one oxide selected from indium, tin, antimony, lead, and titanium can be used.
Specifically, for example, indium / tin oxide (ITO), tin oxide (SnO ₂ ), antimony / tin oxide (ATO), antimony oxide (Sb ₂ O ₅ ), lead / titanium oxide (PTO) Ultrafine particles such as can be used.

  In this invention, the hard-coat layer 4 can be comprised similarly to the hard-coat layer 3 with a chromaticity adjustment function, for example except not containing said pigment | dye.

  In this invention, the transparent electrode layer 5 formed in the back surface side of the polyester film 2 in the hard coat film 1 can be set as the structure conventionally known in a touch panel, for example.

Examples of the material of the transparent electrode layer 5 include metal oxides such as indium / tin oxide (ITO), antimony / tin oxide (ATO), ZnO, Al-doped ZnO, and SnO ₂ . In particular, in the present invention, when ITO that has been conventionally used as a material for the transparent electrode layer 5 is used, the yellow color caused by the ITO is canceled by light absorption in the hard coat layer 3 with a chromaticity adjusting function, thereby transmitting the transparent color. Can be neutral.

  The thickness of the transparent electrode layer 5 is, for example, 1 to 500 nm. The transparent electrode layer 5 can be formed according to a conventional method, for example, can be formed by a sputtering method.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.
<Example 1>
As the polyester film, a polyethylene terephthalate (PET) film (“A4300” manufactured by Toyobo Co., Ltd., PET film thickness 100 μm, with easy adhesion layer) was used.

  In addition, as an ultraviolet curable resin composition for forming a hard coat layer having a chromaticity adjusting function, a pigment is added to an acrylic ultraviolet curable resin (“Seika Beam PET-HC301” manufactured by Dainichi Seika Kogyo Co., Ltd., solid content 50%). As a mixture, 0.005% by mass of a spirone dye ("Aizen Spilon violet C-RH" manufactured by Hodogaya Chemical Co., Ltd.) was used.

  The ultraviolet curable resin composition for forming the hard coat layer was applied to the surface of the polyester film with a wire bar coater # 10.

This was dried at 80 ° C. for 5 minutes, and then cured by UV irradiation (450 mJ / cm ² ) to form a 5 μm thick hard coat layer with a chromaticity adjusting function, thereby obtaining a hard coat film.
<Example 2>
A hard coat film was obtained in the same manner as in Example 1 except that the amount of the spiro dye was changed to 0.0025% by mass in Example 1.
<Example 3>
In Example 1, a hard coat film was obtained in the same manner as in Example 1 except that the blending amount of the spirone dye was changed to 0.010% by mass.
<Example 4>
In Example 1, the spirone dye was changed to “Aizen Spilon Blue GNH” manufactured by Hodogaya Chemical Co., Ltd., and this was blended in an acrylic ultraviolet curable resin in an amount of 0.005% by mass to obtain an ultraviolet curable resin composition. Prepared. Otherwise, a hard coat film was obtained in the same manner as in Example 1.
<Comparative Example 1>
In Example 1, a hard coat film was obtained in the same manner as in Example 1 except that no dye was added to the ultraviolet curable resin composition.

  The transmission chromaticity was measured for the hard coat films of Examples and Comparative Examples. The transmission chromaticity was measured according to JIS K5600 using a spectrocolorimeter (“CM-3600d” manufactured by Konica Minolta).

  The measurement results are shown in Table 1.

  From Table 1, in Examples 1 to 4 in which a pigment is mixed in the hard coat layer, the chromaticity of the transmitted color in the L * a * b * color system is −1 ≦ a * ≦ 1, −2 ≦ b * ≦ 0. The chromaticity of the hard coat film could be adjusted within the range in which the color tone of the transmitted color became neutral even when a transparent electrode layer such as ITO was provided.

  On the other hand, in Comparative Example 1 in which no pigment was added to the hard coat layer, the chromaticity of the transmitted color in the L * a * b * color system was yellow when a transparent electrode layer such as ITO was provided and used as a touch panel. It became a tasteful value.

1 Hard Coat Film 2 Polyester Film 3 Hard Coat Layer with Chromaticity Adjustment Function 4 Hard Coat Layer 5 Transparent Electrode Layer

Claims (5)

  It is a hard coat film for a touch panel in which a transparent electrode layer is formed on the back side of the polyester film, and has a hard coat layer with a chromaticity adjusting function containing a pigment on at least one side of the front and back sides of the polyester film, A hard coat film, wherein the chromaticity of the transmitted color in the L * a * b * color system is in the range of −1 ≦ a * ≦ 1 and −2 ≦ b * ≦ 0.8.   2. The hard coat according to claim 1, wherein the dye contained in the hard coat layer with a chromaticity adjusting function has a maximum peak wavelength of absorbance within a wavelength range of 550 to 600 nm in the visible light region. the film.   The dye contained in the hard coat layer with chromaticity adjusting function is at least one selected from phthalocyanine dyes, indigo dyes, azo dyes, and quinone dyes. The hard coat film as described.   The hard coat film according to any one of claims 1 to 3, further comprising a hard coat layer with a chromaticity adjusting function on a front surface and a back surface of the polyester film.   The hard coat film according to any one of claims 1 to 3, wherein a hard coat layer is provided on each of the front and back surfaces of the polyester film, at least one of which is a hard coat layer with a chromaticity adjusting function.

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