JP2014206707A - Optical hard coat material and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical hard coat material having a hard coat layer, which has superior flexibility, adhesiveness, surface hardness, and blocking resistance and is free from transparency degradation, formed on one surface of an acrylic base material.SOLUTION: In an optical hard coat material 1, a first hard coat layer 12, a second hard coat layer 13, and a low refractive index layer 14 are sequentially laminated on an acrylic base material 11. The first hard coat layer 12, as a single layer, has micro indentation hardness in a range of 0.20 to 0.40 GPa, inclusive, at a depth of 50 nm, while the second hard coat layer 13, as a single layer, has micro indentation hardness in a range of 0.40 to 0.60 GPa, inclusive, at a depth of 50 nm and has a surface with arithmetic average roughness (Ra) in a range of 3 to 50 nm, inclusive.

Description

  The present invention relates to a hard coat material, and in particular, a hard coat layer applied to a display screen of a display such as a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), or an organic EL display. The present invention relates to an optical hard coat material provided with a display device and an optical hard coat material.

  An image display surface in an image display device such as a liquid crystal display device (LCD) or a cathode ray tube display device (CRT) is required to have hardness so as not to be scratched during handling. On the other hand, it has been studied to improve the hardness of the image display surface of the image display device by using an optical laminate in which a hard coat (HC) layer is formed on a base film.

  Technologies to harden the plastic surface include coating a thermosetting resin such as organosiloxane and melamine, forming a metal thin film by vacuum deposition or sputtering, or polyfunctional acrylate-based active energy. Examples thereof include a method of coating a linear curable resin. Among the highly transparent plastic substrate films, triacetyl cellulose (TAC) films and acrylic films are mainly used as substrate films for liquid crystal displays (LCDs) because of their excellent transparency.

  However, in the conventional hard coat material used as the acrylic film supporting substrate, it is a problem that both flexibility and hardness cannot be achieved due to the poor flexibility of the acrylic substrate. Moreover, in the use of an acrylic base material, it becomes a subject that the adhesiveness of an acrylic base material and a hard-coat layer cannot be taken. Furthermore, when film formation is performed by a roll-to-roll process, blocking (adhesion) occurs due to poor slipperiness of the film, and the film surface may be roughened when peeling. It has become a challenge. In view of this, a method has been proposed for achieving both flexibility and hardness, good adhesion, and blocking resistance when formed into a roll.

  In Patent Document 1, a hard coat containing urethane acrylate for imparting flexibility and colloidal silica for imparting hardness is formed on a transparent substrate to try to achieve both flexibility and surface hardness. . However, when the acrylic base material is used, the flexibility is insufficient.

  Patent Document 2 proposes a method of laminating two layers of a hard coat layer with a controlled elongation rate on a transparent substrate. However, this technique has a problem that the surface hardness is insufficient when an acrylic base material is used.

  Further, Patent Document 3 proposes the expression of blocking resistance by a method in which a spacer such as a tape is sandwiched between both ends of a film and a method in which fine irregularities are provided on the film surface. However, in these methods, the process of removing the tape at the time of film processing is complicated, and there is a problem that the transparency of the film deteriorates due to fine irregularities on the film surface.

JP 2007-284626 A JP 2005-305383 A Japanese Patent Laid-Open No. 2005-144858

  An object of the present invention is to provide an optical hard coat material having a hard coat layer which is excellent in flexibility, adhesion, surface hardness, blocking resistance and has no deterioration in transparency on one surface of an acrylic substrate. To do.

As means for solving the above-mentioned problems, in the invention according to claim 1, the first hard coat layer, the second hard coat layer, and the low refractive index layer are sequentially laminated on one surface of the acrylic substrate. An optical hard coat material,
In the single hard layer of the first hard coat layer, the ultra fine indentation hardness at a depth of 50 nm is in the range of 0.20 GPa or more and 0.40 GPa or less,
And in the range of 0.40 GPa or more and 0.60 GPa or less ultra-fine indentation hardness at a depth of 50 nm in the single layer of the second hard coat layer,
And the arithmetic mean roughness (Ra) of said 2nd hard-coat layer surface is 3-50 nm or less in range,
And the thickness of the first hard coat layer is in the range of 0.1 to 10 μm, and the thickness of the second hard coat layer is in the range of 1 to 5 μm.
There is an optical hard coat material.

  In the invention according to claim 2, the ionizing radiation of the polymerizable compound in which the first hard coat layer is selected from monofunctional or bifunctional (meth) acrylate and trifunctional or lower urethane (meth) acrylate. 2. The optical hard coat material according to claim 1, wherein the optical hard coat material is a curable composition.

  In the invention according to claim 3, the second hard coat layer contains fine particles having a particle size of 50 to 700 nm with respect to the total solid content of the second hard coat layer forming coating solution. 3. The optical hard coat material according to claim 1, comprising 0% by weight.

  In the invention according to claim 4, a low refractive index layer having a refractive index during curing of greater than 1.30 and less than 1.40 is formed on the second hard coat layer. The optical hard coat material according to any one of claims 1 to 3, wherein 0.5 to 1.5% and a total light transmittance is 94.0% or more. .

  The invention according to claim 5 is a display device comprising the optical hard coat material according to any one of claims 1 to 4.

  According to the first aspect of the present invention, when the first hard coat layer and the second hard coat layer are laminated on one surface of the acrylic substrate, the first hard coat layer has a sufficient hardness. By making the hardness after curing lower than the hardness after curing of the second hard coat layer, the hardness of the acrylic substrate, the first hard coat layer, and the second hard coat layer can be inclined. A hard coat material excellent in flexibility and adhesiveness is obtained, and the first hard coat layer is formed in a range of 0.1 to 10 μm so that the first hard coat layer and the acrylic base material The effect of the primer for improving the adhesion to the two hard coat layers is obtained, and sufficient hardness is obtained by setting the film thickness of the second hard coat layer, which is the decisive factor of the hardness, to 1 to 5 μm. It is done.

  According to claim 2 of the present invention, the first hard coat layer is an ionization of a polymerizable compound selected from monofunctional or bifunctional (meth) acrylate and trifunctional or lower urethane (meth) acrylate. By comprising a radiation cured product, the hardness of the second hard coat layer can be made higher than that of the first hard coat layer after curing, and the acrylic substrate, the first hard coat layer, and the second hard coat layer And the hardness can be inclined.

  Moreover, according to claim 3 of the present invention, the second hard coat layer has a content of 0.5 to 5.0 parts by weight of fine particles of 50 nm to 700 nm in a film while suppressing the addition amount. Since fine irregularities can be imparted to the surface, an increase in haze value can be suppressed and blocking resistance can be imparted.

  According to claim 4 of the present invention, on the second hard coat layer, a low refractive index layer having a refractive index at the time of curing of greater than 1.30 and less than 1.40 is formed. By setting the reflectance to 0.5% to 1.5% and the total light transmittance to 94.0% or more, an excellent antireflection effect can be obtained.

  As described above, according to the present invention, it is possible to provide a hard coat material having excellent flexibility, excellent adhesion, excellent blocking resistance, and excellent surface hardness.

It is a schematic cross section of one embodiment of the hard coat material concerning the present invention. It is a schematic cross section of one embodiment of a hard coat material having an antireflection function according to the present invention. It is a schematic cross section of the polarizing plate using the hard-coat material shown in FIG. It is a schematic cross section of the transmissive liquid crystal display device using the hard-coat material shown in FIG. It is a schematic cross section of another transmissive liquid crystal display device using the hard-coat material shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a film cross-sectional view of one embodiment of a hard coat material according to the present invention. The hard coat material of the present invention is characterized in that a first hard coat layer 12 and a second hard coat 13 having fine particles 131 are sequentially laminated on an acrylic substrate 11.

  FIG. 2 shows a schematic cross-sectional view of an embodiment of a hard coat material having an antireflection function according to the present invention. That is, it is a hard coat material having an antireflection effect obtained by forming a low refractive index layer 14 on the second hard coat layer 13 having the configuration shown in FIG.

  The first hard coat layer 12 according to the embodiment of the present invention is a cured film of an ionizing radiation curable composition having an ultra-fine indentation hardness at a depth of 50 nm in a range of 0.20 GPa to 0.40 GPa. Have Further, the second hard coat layer 13 has a feature that it is a cured film of an ionizing radiation curable composition having an ultra-fine indentation hardness of 50 nm in a range of 0.40 GPa or more and 0.80 GPa or less. In the ionizing radiation curable composition according to the present invention, an ionizing radiation curable material such as an ultraviolet curable material or an electron beam curable material can be used.

  As the ionizing radiation curable material used for the first hard coat layer, monofunctional (monofunctional) or bifunctional acrylate compounds can be used.

For example, monofunctional (meth) acrylate compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, t-butyl (meth) acrylate, glycidyl (meth) acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfuryl acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) ) Acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phosphoric acid (meth) acrylate, ethylene oxide modified phosphoric acid (meth) acrylate, phenoxy (meta ) Acrylate, ethylene oxide modified phenoxy (meth) acrylate, propylene oxide modified phenoxy (meth) acrylate, nonylphenol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, propylene oxide modified nonylphenol (meth) acrylate, methoxydiethylene glycol (meth) Acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen Phthalate, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate , Hexafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, octafluoropropyl (meth) acrylate, 2 -Adamantane derivatives mono (meth) acrylates such as adamantyl acrylate having a monovalent mono (meth) acrylate derived from adamantane and adamantanediol.

  For example, bifunctional (meth) acrylate compounds include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, and nonanediol di (meth) acrylate. , Ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) ) Acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, tripropylene glycol (Meth) acrylate, di (meth) acrylate, such as hydroxypivalic acid neopentyl glycol di (meth) acrylate.

  As the ionizing radiation effect material used in the second hard coat layer, the following polyfunctional polymerizable compounds can be used in addition to the monofunctional or bifunctional acrylate compounds.

  Examples of the polyfunctional (meth) acrylate compound include trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, and tris-2-hydroxyethyl isocyanate. Trifunctional such as tri (meth) acrylate such as nurate tri (meth) acrylate and glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate (Meth) acrylate compounds, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate and more polyfunctional (meth) acrylates Examples thereof include a compound and a polyfunctional (meth) acrylate compound in which a part of these (meth) acrylates is substituted with an alkyl group or ε-caprolactone.

  Polyfunctional urethane (meth) acrylate compounds include pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, dipentaerythritol. Pentaacrylate, toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer, and the like can be used.

  The film thickness of the first hard coat layer 12 is in the range of 0.1 to 10 μm, and the film thickness of the second hard coat layer 13 is preferably in the range of 1 to 5 μm. When the film thickness of the first hard coat layer 12 is 0.1 μm or less, flexibility cannot be obtained and the flexibility is deteriorated, and when it is 10 μm or more, the surface hardness is lowered. Further, when the thickness of the second hard coat layer 13 is less than 1 μm, the surface hardness is low, and when it is thicker than 10 μm, the flexibility is deteriorated.

  The kind of fine particles added to the second hard coat layer 13 has an average particle diameter of 50 nm to 700 nm, and preferably has a haze value of 0.5% or less. There is no particular limitation as long as it is sufficient. For example, translucent organic resin particles such as polymethyl methacrylate fine particles and polymethyl methacrylate-polystyrene copolymer fine particles, and inorganic fillers such as silica may be used.

  The average particle diameter of the fine particles is 50 nm to 700 nm, preferably 80 to 500 nm. When the average particle diameter of the fine particles is less than 50 nm, the fine particles are buried in the binder matrix, and unevenness cannot be imparted on the second hard coat layer 13, and the effect of improving blocking resistance is not exhibited. On the other hand, when the average particle diameter of the fine particles exceeds 700 nm, the light is significantly scattered and the haze value is increased.

  The content of the fine particles is 0.5 to 5.0 parts by weight, preferably 0.8 to 3.0 parts by weight with respect to 100 parts by weight of the total solid content of the coating liquid for forming the second hard coat layer 13. is there. When the content of the fine particles is less than 0.5 parts by weight, the optical hard coat material cannot be provided with such unevenness that the fine particles are few and the blocking resistance is exhibited. On the other hand, when the content of fine particles exceeds 5.0 parts by weight, light scattering occurs in the fine particles, and the haze value increases.

  The hard coat of the present invention obtained by setting the average particle diameter of the fine particles to 50 nm to 700 nm and the content to 0.5 to 5.0 parts by weight, the center line average roughness (Ra ) Is 3 to 50 nm, preferably 5 to 30 nm, blocking resistance is exhibited, and an increase in haze value can be suppressed. When the center line average roughness on the surface of the second hard coat layer 13 is less than 3 nm, the surface of the second hard coat layer 13 becomes flat, and blocking may easily occur. On the other hand, when the center line average roughness of the second hard coat layer 13 exceeds 50 nm, the antireflection film may appear to be whitened due to surface irregularities.

The film thickness of the second hard coat layer 13 is 1 μm to from the viewpoint of flexibility and surface hardness.
The thickness of the second hard coat layer 13 must be 5 μm or less in order to impart blocking resistance by adding fine particles. If the thickness of the second hard coat layer 13 is made thicker than 5 μm, the fine particles are buried in the binder matrix, and unevenness cannot be imparted on the second hard coat layer 13, and blocking resistance is improved. Improvement effect does not appear.

  The optical hard coat material of the present invention may be a hard coat layer (antistatic hard coat) in which the second hard coat layer 13 has an antistatic effect.

  A solvent can be added to the composition forming the first hard coat layer 12 and the second hard coat layer 13 as necessary, for example, in order to improve the coating suitability. Solvents include aromatic hydrocarbons such as toluene, xylene, cyclohexane and cyclohexylbenzene, hydrocarbons such as n-hexane, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, and trioxane. , Ethers such as tetrahydrofuran, anisole and phenetole, and ketones such as methyl isobutyl ketone, methyl butyl ketone, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, and methylcyclohexanone , Ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, Esters such as acid n-pentyl and γ-ptyrolactone, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and ethylene glycol It is appropriately selected from water and the like in consideration of appropriate coating.

  In addition, in the composition forming the first hard coat layer 12 and the second hard coat layer 13, in order to prevent the occurrence of coating film defects such as repellency and unevenness when the composition is applied, Additives that are called may be added. Surface modifiers are also called leveling agents, antifoaming agents, interfacial tension modifiers, and surface tension modifiers, depending on their function, all of which reduce the surface tension of the coating film (antiglare layer) that is formed. Is provided.

  In addition, in the composition for forming the first hard coat layer 12 and the second hard coat layer 13, other additives may be added in addition to the surface conditioner described above. As the functional additive, an ultraviolet absorber, an infrared absorber, an adhesion improver, a curing agent, or the like can be used.

  The optical hard coat material according to the present invention is obtained by applying the composition of the first hard coat layer 12 and the second hard coat layer 13 prepared with the above-mentioned additives onto an acrylic substrate, and drying as necessary. Then, it can be produced by irradiating with ionizing radiation such as ultraviolet rays or electron beams.

  For the application of the composition, a coating apparatus such as a roll coater, a reverse roll coater, a gravure coater, a micro gravure coater, a knife coater, a bar coater, a wire bar coater, a die coater, or a dip coater can be used. Also, two layers of the first hard coat layer 12 and the second hard coat layer 13 can be applied in succession.

  Further, as the ionizing radiation, ultraviolet rays and electron beams can be used. In the case of ultraviolet curing, a light source such as a high pressure mercury lamp, a low pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a carbon arc, or a xenon arc can be used. In the case of electron beam curing, electron beams emitted from various electron beam accelerators such as cockloftwald type, bandegraph type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type can be used. .

  In addition, you may provide a drying process or a heating process before and after irradiation of the said ionizing radiation. In particular, when the composition contains a solvent, it is necessary to provide a drying step before irradiation with ionizing radiation in order to remove the solvent of the formed coating film. Examples of the drying means include heating, air blowing, and hot air.

  Further, the hard coat material having an antireflection function according to the present invention (hereinafter simply referred to as an antireflection hard coat material 2) has a low refractive index layer 14 exhibiting an antireflection function on the second hard coat layer 13. It is obtained by forming.

  As the method for forming the low refractive index layer, a wet film forming method in which a composition for forming a low refractive index layer is applied to the surface of the hard coat layer to form an antireflection layer, a vacuum deposition method, a sputtering method, or a CVD method. The method can be divided into vacuum deposition methods that form an antireflection layer in a vacuum. In particular, a method for forming a low refractive index layer by a wet film-forming method (coating) using a composition for forming a low refractive index layer containing low refractive index particles and a binder matrix should be excellent in productivity and inexpensive. It is preferable at the point which can do.

  At this time, the low refractive index layer 14 has an optical film thickness (nd) obtained by multiplying the film thickness (d) by the refractive index (n) of the low refractive index layer 14 to 1/4 of the wavelength of visible light. Designed and formed to be equal.

  The low refractive index layer 14 of the antireflection hard coat material 2 of the present invention has a refractive index greater than 1.30 and less than 1.40, and a luminous average reflectance of 0.5% or more and 1.5%. The following is preferred. When the refractive index is 1.30 or less, the scratch resistance becomes insufficient, and the use on the image display surface becomes difficult. Further, when the refractive index when the low refractive index layer is cured is 1.40 or more, there is a problem that the average luminous reflectance is increased and the function of preventing reflection is lowered.

  As the optical hard coat material of the present invention, for example, an antiglare layer, an ultraviolet absorption layer, an infrared absorption layer, and the like can be provided between the second hard coat layer 13 and the low refractive index layer 14. There is a possibility that the light transmittance may be lowered, and it is necessary to consider the balance.

  The optical hard coat material according to the present invention can be used for LCD, PDP, CRT, projection, EL display and the like. The case where the antireflection hard coat material 2 of the present invention is used as a member of a liquid crystal display will be described below.

  FIG. 3 shows a schematic cross-sectional view of a polarizing plate 3 using the antireflection hard coat material 2 of the present invention. That is, the polarizing plate is formed by sequentially laminating the polarizing layer 23 and the transparent substrate 21 on the other surface of the acrylic substrate 11. For example, the transparent substrate 21 may be an acrylic substrate. As the polarizing layer 23, a stretched polyvinyl alcohol film to which iodine is added can be used. These are one embodiment and are not particularly limited.

  FIG. 4 shows a schematic cross-sectional view of a transmissive liquid crystal display body provided with the antireflection hard coat material 2 of the present invention.

  FIG. 4 shows a transmissive liquid crystal display using the polarizing plate 3 shown in FIG. 3, which is constructed by laminating a backlight unit 6, a second polarizing plate 5, a liquid crystal cell 4 and a polarizing plate 3 in order. 1 shows a transmissive liquid crystal display. That is, the low refractive index layer 14 side of the antireflection hard coat material 2 is the observation side (the surface of the display body).

On the other hand, FIG. 5 shows a backlight unit 6, a second polarizing plate 5, a liquid crystal cell 4, a polarizing plate 3 ′,
2 shows a transmissive liquid crystal display body formed by sequentially laminating antireflection hard coat materials 2. The polarizing plate 3 ′ has a configuration in which the polarizing layer 23 is sandwiched between the transparent substrates 21 and 22 from both sides. The transparent substrates 21 and 22 constituting the polarizing plates 3 and 3 ′ used in FIGS. 4 and 5 and the transparent substrates 42 and 43 used for the second polarizing plate 5 may be acrylic substrates, and are particularly limited. is not.

  The backlight unit 6 includes a light source and a light diffusing plate. The liquid crystal cell 4 has a structure in which an electrode is provided on one transparent substrate, an electrode and a color filter are provided on the opposite transparent substrate, and liquid crystal is sealed between the electrodes.

  Hereinafter, specific examples will be described. Fourteen compositions for forming the hard coat layer and three compositions for forming the low refractive index layer were prepared with the following compositions.

  As the composition for the first hard coat layer, two kinds of first hard coat layer compositions whose single layer hardness falls within the range of 0.20 to 0.40 GPa, and two kinds of first hard coats that are out of the range for comparison. The composition of the coating layer composition is shown below.

<First hard coat layer composition 1>
Trifunctional urethane acrylate: Nippon Synthetic Chemical Co., Ltd. UV75550-B 50 parts by weight Monofunctional monomer: Kyoeisha Chemical Co., Ltd. Isoamyl acrylate 50 parts by weight Photopolymerization initiator: BASF, Irgacure 184 10 parts by weight Solvent: Methyl ethyl ketone 100 parts by weight Yes, the single layer hardness is 0.26 GPa.

<Composition 2 for the first hard coat layer>
Trifunctional urethane acrylate: 70 parts by weight UV7550-B manufactured by Nippon Synthetic Chemical Co., Ltd. Bifunctional monomer: 30 parts by weight manufactured by Kyoeisha Chemical Co., Ltd.
Polyethylene glycol # 200 diacrylate photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight, single layer hardness is 0.35 GPa.

<First hard coat layer composition 3 (for comparison)>
Trifunctional urethane acrylate: Nippon Synthetic Chemical Co., Ltd. UV75550-B 30 parts by weight Monofunctional monomer: Kyoeisha Chemical Co., Ltd. Isoamyl acrylate 70 parts by weight Photopolymerization initiator: BASF, Irgacure 184 10 parts by weight Solvent: Methyl ethyl ketone 100 parts by weight Yes, the single layer hardness is 0.18 GPa.

<First hard coat layer composition 4 (for comparison)>
4- to 5-functional urethane acrylate: 70 parts by weight of UV7650-B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl keto 100 parts by weight, single layer hardness is 0.46 GPa.

  Fine particles were added to the composition for the second hard coat layer, and 10 types of compositions for the first hard coat layer were prepared. Its composition is shown below.

<Second hard coat layer composition 1>
4- to 5-functional urethane acrylate: 70 parts by weight of UV7650-B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 2>
Hexafunctional urethane acrylate: Kyoeisha Chemical Co., Ltd. UA306-I 70 parts by weight Trifunctional monomer: Osaka Organic Chemical Co., Ltd. V # 300 30 parts by weight
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 3>
Hexafunctional urethane acrylate: Kyoeisha Chemical Co., Ltd. UA306-I 70 parts by weight Trifunctional monomer: Osaka Organic Chemical Co., Ltd. V # 300 30 parts by weight
Pentaerythritol triacrylate silica fine particle dispersion: average particle diameter 500 nm 2 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 4>
Hexafunctional urethane acrylate: Kyoeisha Chemical Co., Ltd. UA306-I 70 parts by weight Trifunctional monomer: Osaka Organic Chemical Co., Ltd. V # 300 30 parts by weight
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 1.5 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 5>
4- to 5-functional urethane acrylate: Nippon Synthetic Chemical Co., Ltd. UV7650-B 70 parts by weight Trifunctional monomer: Osaka Organic Chemistry V # 300 30 parts by weight
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 0.3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 6>
4- to 5-functional urethane acrylate: 70 parts by weight of UV7650-B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 30 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 7 (for comparison)>
4- to 5-functional urethane acrylate: 70 parts by weight of UV7650-B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 10 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 8 (for comparison)>
4- to 5-functional urethane acrylate: 70 parts by weight of UV7650-B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate silica fine particle dispersion: average particle diameter 1000 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 9 (for comparison)>
Trifunctional urethane acrylate: 70 parts by weight of UV7550B manufactured by Nippon Synthetic Chemical Co., Ltd. Trifunctional monomer: 30 parts by weight of V # 300 manufactured by Osaka Organic Chemical Co., Ltd.
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

<Second hard coat layer composition 10 (for comparison)>
10 functional urethane acrylate: Nippon Synthetic Chemical Co., Ltd. UV1700B 70 parts by weight Trifunctional monomer: Osaka Organic Chemical Co., Ltd. V # 300 30 parts by weight
Pentaerythritol triacrylate silica fine particle dispersion: average particle size 300 nm 3 parts by weight
Solid content 30%, solvent methyl isobutyl ketone photopolymerization initiator: BASF Corporation, Irgacure 184 10 parts by weight Solvent: methyl ethyl ketone 100 parts by weight.

  The low refractive index layer composition has the following three types of compositions in which the refractive index during curing is changed to 1.30, 1.36, and 1.40.

<Low refractive index layer composition 1>
Porous silica fine particle dispersion: average particle size 50 nm 14.94 parts by weight
Solid content 20%, solvent: methyl isobutyl ketone EO-modified dipentaerythritol hexaacrylate 1.99 parts by weight
DPEA-12 made by Nippon Kayaku
Photopolymerization initiator: BASF's Irgacure 184 0.07 part by weight Alkyl polyether-modified silicone oil 0.20 part by weight
TSF4460 made by GE Toshiba Silicone
Solvent: 82 parts by weight of methyl isobutyl ketone.

<Composition 2 for low refractive index layer>
Porous silica fine particle dispersion: average particle size 50 nm 16.12 parts by weight
20% solid content, solvent: 0.81 parts by weight of methyl isobutyl ketone EO-modified dipentaerythritol hexaacrylate
DPEA-12 made by Nippon Kayaku
Photopolymerization initiator: 0.07 parts by weight
Irgacure 184, manufactured by Ciba Specialty Chemicals
Alkyl polyether modified silicone oil 0.20 parts by weight
TSF4460 made by GE Toshiba Silicone
Solvent: 82 parts by weight of methyl isobutyl ketone.

<Composition 3 for low refractive index layer>
Porous silica fine particle dispersion: average particle size 50 nm 13.02 parts by weight
Solid content 20%, solvent: methyl isobutyl ketone EO-modified dipentaerythritol hexaacrylate 3.91 parts by weight
DPEA-12 made by Nippon Kayaku
Photopolymerization initiator 0.07 parts by weight
Irgacure 184, manufactured by Ciba Specialty Chemicals
Alkyl polyether modified silicone oil 0.20 parts by weight
TSF4460 made by GE Toshiba Silicone
Solvent: 82 parts by weight of methyl isobutyl ketone.

The first hard coat layer composition 1 is used as the first hard coat layer, the second hard coat layer composition 1 is used as the second hard coat layer, and the low refractive index layer composition 1 is used as the low refractive index layer composition. The first hard coat layer composition 1 is applied to one surface of an acrylic substrate having a thickness of 80 μm so that the film thickness after curing is 5 μm, and the second hard coat layer composition 1 is further cured. The film is applied to a thickness of 3 μm, dried in an oven at 80 ° C. for 60 seconds, and then irradiated with ultraviolet rays at an irradiation dose of 300 mJ / cm ² using an ultraviolet irradiation device (Fusion UV System Japan, light source H bulb). A hard coat layer was formed.

On top of this, the composition 1 for a low refractive index layer was applied so that the film thickness after drying was 100 nm. Thereafter, using a UV irradiation device (light source H bulb manufactured by Fusion UV System Japan), a low refractive index layer was formed by UV irradiation at an irradiation dose of 192 mJ / cm ² to prepare an antireflection hard coat material.

  An antireflective hard coat material was produced under the same conditions except that the composition 2 for the second hard coat layer was used as the second hard coat layer in Example 1 and the hardness of the second hard coat layer in the single layer was increased. .

  An anti-reflective hard coat material was produced under the same conditions except that the composition 2 for the first hard coat layer was used as the first hard coat layer in Example 1 and the hardness of the first hard coat layer in the single layer was increased. did.

  An antireflection hard coat material was produced under the same conditions except that the film thickness of the first hard coat layer and the film thickness of the second hard coat layer in Example 1 were increased.

  An antireflection hard coat material was produced under the same conditions except that the film thickness of the first hard coat layer and the film thickness of the second hard coat layer in Example 1 were reduced.

  As the second hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions except that the composition 3 for the second hard coat layer in which the fine particle diameter was increased and the addition amount was reduced was used.

  As the second hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions except that the second hard coat layer composition 4 in which the addition amount of fine particles was reduced was used.

  As the second hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions except that the composition 4 for the first hard coat layer to which fine particles were not added was used.

  As the second hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions using the second hard coat layer composition 5 in which the amount of fine particles added was one-tenth that of Example 1.

  As the second hard coat layer in Example 1, the antireflective hard was used under the same conditions except that the composition 7 for the second hard coat layer in which the added fine particle size in Example 1 was 1/10 of that in Example 1 was used. A coating material was prepared.

  Instead of the low refractive index layer composition 1 in Example 1, an antireflection hard coat material was produced under the same conditions except that the low refractive index layer composition 2 was used.

  Instead of the low refractive index layer composition 1 in Example 1, an antireflection hard coat material was produced under the same conditions except that the low refractive index layer composition 3 was used.

<Comparative Example 1>
As the second hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions except that the second hard coat layer composition 7 in which fine particles were added three times or more of Example 1 was used.

<Comparative example 2>
Reflection was performed under the same conditions except that the second hard coat layer in Example 1 used was a composition 8 for the second hard coat layer in which the added fine particle size in Example 1 was 3.3 times or more that in Example 1. A preventive hard coat material was prepared.

<Comparative Example 3>
As the first hard coat layer in Example 1, an antireflection hard coat material was produced under the same conditions except that the composition 3 for the first hard coat layer in which the trifunctional urethane acrylate was reduced and the monofunctional monomer was increased was used.

<Comparative example 4>
As the first hard coat layer in Example 1, a tetrafunctional to pentafunctional urethane acrylate was used instead of the trifunctional urethane acrylate, the monofunctional monomer was a trifunctional monomer, and the number of functional groups was increased. An antireflection hard coat material was produced under the same conditions except that 4 was used.

<Comparative Example 5>
Instead of the tetra- to pentafunctional urethane acrylate of the second hard coat layer composition in Example 1, the second hard coat layer composition 9 was used as a trifunctional urethane acrylate, and the hardness at the time of single layer after curing was softened. An antireflection hard coat material was produced under the same conditions except for the above.

<Comparative Example 6>
Anti-reflective hard coat material under the same conditions except that a ten-functional urethane acrylate was used instead of the tetra- to pentafunctional urethane acrylate of the composition for the second hard coat layer in Example 1 and the hardness at the time of single layer after curing was increased. Was made.

<Comparative Example 7>
An antireflection hard coat material under the same conditions except that the composition 1 for the second hard coat layer to which fine particles are added is used as the first and second hard coat layers in Example 1 and the film thickness is 5 μm. Was made.

<Comparative Example 8>
An antireflection hard coat material was produced under the same conditions except that the thickness of the first hard coat layer in Example 1 was set to 1/100.

<Comparative Example 9>
An antireflection hard coat material was produced under the same conditions except that the thickness of the first hard coat layer in Example 1 was tripled.

<Comparative Example 10>
An antireflection hard coat material was produced under the same conditions except that the thickness of the second hard coat layer in Example 1 was reduced to about 1/4.

<Comparative Example 11>
An antireflection hard coat material was produced under the same conditions except that the thickness of the second hard coat layer in Example 1 was increased to 5 times.

<Evaluation and method>
The hard coat layers and antireflection hard coat materials obtained in Examples 1 to 12 and Comparative Examples 1 to 11 were tested and evaluated by the following methods.

<Ultra indentation hardness>
Using a super micro indentation hardness tester (NanoIndenter SA2 manufactured by MTS Systems), the hardness of the hard coat layer is 50 nm deep. Indenter: Triangular pyramid indenter with tip radius of curvature of 100 nm and ridge angle of 80 °, indentation speed = Measurement was performed under the condition of 2.0 nm / s.

<Pencil hardness test>
Using a Clemens type scratch hardness tester (manufactured by Tester Sangyo Co., Ltd., HA-301), a load of 500 g is applied to the surface of the low refractive index layer of the antireflection hard coat material in accordance with JIS-K5400-1990. Using a pencil (Mitsubishi Pencil Co., Ltd. UNI), the pencil hardness was changed and the test was performed to visually evaluate the change in appearance due to scratches, and the upper limit pencil hardness when no scratches were observed was taken as the measured value. .

<Flexibility evaluation>
A mandrel test was carried out according to K5600-5-1, and the mandrel diameter when a crack occurred was evaluated.
Evaluation was made assuming that the radius of curvature at which the crack occurred was a circle (◯): 10 mm or less, a cross mark (×): greater than 10 mm.

<Average luminous reflectance>
The surface of the low refractive index layer was measured for spectral reflectance at an incident angle of 5 ° using an automatic spectrophotometer (Hitachi, U-4000). Further, the average luminous reflectance was obtained from the obtained spectral reflectance curve. In the measurement, a matte black coating amount was applied to the surface of the acrylic base material on which the low refractive index layer was not formed, and an antireflection treatment was performed.

<Haze value>
About the obtained anti-reflective film, the haze value was measured based on the method as described in JISK7105-1981 using the image clarity measuring device (NDH-2000 by Nippon Denshoku Industries Co., Ltd.).

<Total light transmittance>
About the said antireflection hard coat material, the total light transmittance was measured using the image clarity measuring device (Nippon Denshoku Industries Co., Ltd. NDH-2000). The measured result is
Evaluation was performed with a circle mark (◯): 94% or more and a cross mark (x): less than 94%.

<Adhesion>
The surface of the antireflective hard coat material on the low refractive index layer side was subjected to an adhesion test in accordance with the cross-cut method of JIS-K-5600-5-6.
The interval between cuts is 1 mm,
Circle mark (◯): When the grid pattern and the cut intersection are not peeled off at all Cross mark (×): Evaluation is made as if even a little peeled off.

<Abrasion resistance>
The surface of the antireflective hard coat material on the low refractive index layer side was reciprocated 10 times while applying a load of 200 g / cm 2 using # 0000 steel wool, and the presence or absence of scratches was confirmed.
Circle (○): When there is no flaw, a cross mark (×) When a flaw occurs, a cross mark (×)
As an evaluation.

<Refractive index measurement>
As for the refractive index of the low refractive index layer, the composition for low refractive index layer was applied on a silicon substrate so as to have a film thickness of 1.0 μm, and a coating film was formed under the conditions for forming the low refractive index layer. The produced substrate was measured with a vacuum ultraviolet multiple incident angle spectroscopic ellipsometer (VUV-VASE manufactured by JA Woollam).

<Center line average roughness (Ra)>
About the obtained antireflection film, the center line average roughness (Ra) of the surface of the low refractive index layer was measured using a non-contact surface / layer cross-sectional shape measurement system (VertScan 2.0 manufactured by Ryoka System Co., Ltd.).

<Blocking resistance>
The obtained antireflection film was cut into a 10 cm square, 5 sheets of this cut film were stacked on a glass plate, and allowed to stand at 50 ° C. for 24 hours. Then, the area of the blocking part which occupies for a film area (100 cm < ² >) was observed visually.
Circle mark (◯): Evaluation was made when the area of the blocking portion in the film area was less than 50% x (x): 50% or more.

  The evaluation results are shown in Table 1.

表１に示す様に、実施例１〜１２で得られた本発明の光学用ハードコートは、屈曲性、密着性、表面硬度に優れ、特に実施例１〜７では屈曲性、密着性、表面硬度、耐ブロッキング性に優れたものであることがわかる。これに対して、比較例１より、第二ハードコート層に添加される微粉末の添加量が多いと表面の算術平均粗さが悪くなり、また、比較例２より添加される微粉末の粒径が大きいと同様に表面の算術平均粗さが悪くなる。

As shown in Table 1, the optical hard coats of the present invention obtained in Examples 1 to 12 are excellent in flexibility, adhesion, and surface hardness, and in Examples 1 to 7, in particular, flexibility, adhesion, and surface. It turns out that it is excellent in hardness and blocking resistance. On the other hand, when the amount of fine powder added to the second hard coat layer is larger than that of Comparative Example 1, the arithmetic average roughness of the surface is deteriorated. As the diameter is large, the arithmetic average roughness of the surface is deteriorated.

  Moreover, when the single-layer hardness of the first hard coat layer deviates from 0.20 to 0.40 GPa from Comparative Examples 3, 4, and 7, the pencil hardness and the mandrel test are not satisfied. In Comparative Example 3 in which the functional groups of the urethane acrylate and monomer in the composition for the first hard coat layer were reduced, and in contrast, in the case of using the composition for the second hard coat layer, and pencil hardness and mandrel The test and adhesion are not satisfactory.

  Further, from Comparative Examples 5 and 6, the functional group is reduced to trifunctional urethane acrylate instead of the tetra to penta functional urethane acrylate of the second hard coat layer composition, or the decafunctional urethane is replaced with the tetra to penta functional urethane acrylate. Those using acrylates do not satisfy pencil hardness, mandrel test, and adhesion.

  It can be seen that the hard coats obtained in Comparative Examples 1 to 7 cannot be prepared to satisfy all of flexibility, adhesion, surface hardness, and blocking resistance.

DESCRIPTION OF SYMBOLS 1 ... Hard-coat material 11 ... Acrylic base material 12 ... 1st hard-coat layer 13 ... 2nd hard-coat layer 14 ... Low refractive index layer 15 ... Fine particle 2 ... Reflection Prevention hard coat material 21 ... Transparent base material 22 ... Transparent base material 23 ... Polarizing layer 3 ... Antireflection hard coat material integrated polarizing plate 31 ... Polarizing plate 4 ... Liquid crystal cell 41 ... Transparent substrate 42 ... Transparent substrate 43 ... Polarizing layer 5 ... Second polarizing plate 6 ... Backlight

Claims (5)

An optical hard coat material in which a first hard coat layer, a second hard coat layer, and a low refractive index layer are sequentially laminated on one surface of an acrylic substrate,
In the single hard layer of the first hard coat layer, the ultra fine indentation hardness at a depth of 50 nm is in the range of 0.20 GPa or more and 0.40 GPa or less,
And in the range of 0.40 GPa or more and 0.60 GPa or less ultra-fine indentation hardness at a depth of 50 nm in the single layer of the second hard coat layer,
And the arithmetic mean roughness (Ra) of said 2nd hard-coat layer surface is 3-50 nm or less in range,
And the thickness of the first hard coat layer is in the range of 0.1 to 10 μm, and the thickness of the second hard coat layer is in the range of 1 to 5 μm.
An optical hard coat material, characterized in that it exists.   The first hard coat layer is made of an ionizing radiation cured product of a polymerizable compound selected from monofunctional or bifunctional (meth) acrylate and trifunctional or lower urethane (meth) acrylate. The optical hard coat material according to 1.   3. The optical hard coat material according to claim 1, wherein the second hard coat layer contains 0.5 to 5.0 wt% of fine particles having a particle diameter of 50 to 700 nm.   On the second hard coat layer, a low refractive index layer having a refractive index during curing of greater than 1.30 and less than 1.40 is formed, and the luminous average reflectance is 0.5 to 1.5%. And the total light transmittance is 94.0% or more, The optical hard-coat material as described in any one of Claims 1-3 characterized by the above-mentioned.   A display device comprising the optical hard coat material according to claim 1.

Images