Anti-reflective laminate

Abstract

To provide an anti-reflective laminate that has excellent stain resistance without the use of fluorine-based antifouling agents. [Solution] An anti-reflective laminate 1A is formed by laminating a hard coat layer 3, an anti-reflective layer 4, and an overcoat layer 5 in this order on a transparent substrate 2, wherein the anti-reflective layer 4 has at least a low refractive index layer 41 on the overcoat layer 5 side, the low refractive index layer 41 is made of a cured film of a composition mainly composed of alkoxysilane, and the overcoat layer 5 is made of a cured product of a silicon-based compound and has a water contact angle of 100° or more.

Description

Technical Field

[0001] The present invention relates to an antireflection laminate.

Background Art

[0002] Conventionally, an antireflection laminate for preventing reflection on the surface and making the screen easier to view has been attached to the front panel of display devices such as CRT (Cathode-Ray Tube), LCD (Liquid Crystal Display), and PDP (Plasma Display Panel).

[0003] By the way, in touch panels such as cash dispensers (ATMs) and ticket vending machines of financial institutions, an antireflection function has also been required to ensure better visibility. On the other hand, in touch panels, fingerprints are inevitably left due to the lipid content of fingers, and visibility is similarly reduced, so antifouling properties are also required.

[0004] For this reason, an antireflection laminate having an overcoat layer made of a fluorine-based antifouling agent disposed on the outermost surface is used (see, for example, Patent Document 1 below).

[0005] Many fluorine-based antifouling agents are composed of organic fluorine compounds (PFAS) such as perfluoroalkyl compounds, and some exhibit excellent water repellency, oil repellency, heat resistance, weather resistance, etc. Taking advantage of these characteristics, they are used in a wide range of industries such as cooking utensils, packaging, cosmetics, clothing, electronic devices, and automobiles.

[0006] However, PFAS is not only expensive but also has a concern of not being decomposed in the natural environment and accumulating semi-permanently, and some are pointed out to possibly harm the health of humans and animals. Therefore, the regulation of PFAS is being strengthened worldwide. Thus, in the case of antireflection laminates, there is a concern that the use of fluorine-based antifouling agents including PFAS will become difficult, and it is urgent to use non-fluorine-based antifouling agents.

[0007] Examples of non-fluorinated antifouling agents include silicone-based, acrylic-based, and urethane-based agents. However, the use of non-fluorinated antifouling agents as an antifouling layer on top of an anti-reflective coating made of wet coating has not been considered, and its feasibility was unknown. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2019 / 202942 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] This invention was proposed in view of the above conventional circumstances, and aims to provide an anti-reflective laminate that makes it possible to obtain excellent stain resistance, adhesion, and abrasion resistance of the overcoat layer without using a fluorine-based antifouling agent. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides the following means. [1] An anti-reflective laminate in which a hard coat layer, an anti-reflective layer, and an overcoat layer are laminated in this order on a transparent substrate, The anti-reflective layer has at least a low refractive index layer on the overcoat layer side, The low refractive index layer consists of a cured film of a composition mainly composed of alkoxysilane. The anti-reflective laminate is characterized in that the overcoat layer is made of a cured silicon-based compound and has a water contact angle of 100° or more. [2] The anti-reflective laminate according to [1], characterized in that the evaluation in the adhesion test (cross-cut method) of "JIS K 5600-5-6" is 0 or 1. [3] The anti-reflective laminate according to [1], characterized in that the silicon-based compound comprises at least one selected from polysiloxane, silane compound, and organosilazane. [4] The anti-reflective laminate according to [1], characterized in that the low refractive index layer consists of a cured film of a composition mainly composed of alkoxysilane, hollow silica fine particles, and a metal chelate compound. [5] A protective layer is provided between the anti-reflective layer and the overcoat layer. The anti-reflective laminate according to [1], characterized in that the protective layer consists of a cured film of a composition mainly composed of alkoxysilane, spherical silica fine particles with a particle size of 5 to 10 nm, and a metal chelate compound. [Effects of the Invention]

[0011] As described above, the present invention provides an anti-reflective laminate that makes it possible to obtain excellent stain resistance, adhesion, and abrasion resistance of the overcoat layer without using a fluorine-based antifouling agent. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing an example of an anti-reflective laminate according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view showing an example of an anti-reflective laminate according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view showing an example of an anti-reflective laminate according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view showing an example of an anti-reflective laminate according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, the drawings used may schematically show the characteristic parts for the sake of easy understanding of the characteristics, and the dimensional ratios of each component etc. are not necessarily the same as the actual ones. Also, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and it can be implemented by appropriately changing within the range not changing the gist thereof.

[0014] (Anti-reflection laminate) In the present embodiment, for example, anti-reflection laminates 1A to 1D as shown in FIGS. 1 to 4 can be exemplified.

[0015] Specifically, the anti-reflection laminate 1A shown in FIG. 1 has a structure in which a hard coat layer 3, an anti-reflection layer 4 including a low refractive index layer 41, and an overcoat layer 5 are laminated in this order on a transparent substrate 2.

[0016] On the other hand, the anti-reflection laminate 1B shown in FIG. 2 has a structure in which a hard coat layer 3, an anti-reflection layer 4, a protective layer 6, and an overcoat layer 5 are laminated in this order on a transparent substrate 2. Also, the anti-reflection layer 4 is laminated with a medium refractive index layer 42, a high refractive index layer 43, and a low refractive index layer 41 in this order.

[0017] On the other hand, the anti-reflection laminate 1C shown in FIG. 3 has a structure in which a hard coat layer 3, an anti-reflection layer 4, a protective layer 6, and an overcoat layer 5 are laminated in this order on a transparent substrate 2. Also, the anti-reflection layer 4 is laminated with a medium-low refractive index layer 44, a medium refractive index layer 42, a high refractive index layer 43, and a low refractive index layer 41 in this order.

[0018] On the other hand, the anti-reflection laminate 1D shown in FIG. 4 has a structure in which a hard coat layer 3, an antiglare layer 7, an anti-reflection layer 4 including a low refractive index layer 41, a protective layer 6, and an overcoat layer 5 are laminated in this order on a transparent substrate 2.

[0019] 〔Transparent substrate〕 The transparent substrate 2 can be any material, such as a glass substrate or a transparent resin substrate or sheet that has excellent impact resistance and does not obstruct visibility. Specifically, from the viewpoint of transparency and impact resistance, it is preferable to use one made of aromatic polycarbonate resin or polymethyl methacrylate resin. Alternatively, a laminate of aromatic polycarbonate resin and polymethyl methacrylate resin may be used. The thickness of the transparent substrate 2 is selected and designed appropriately based on the required transparency and impact resistance, but is usually selected from a range of 0.2 to 3.0 mm.

[0020] [Hard court layer] The hard coat layer 3 contributes to the strength of the anti-reflective laminates 1A to 1D, as well as to the adhesion between the transparent substrate 2 and the anti-reflective layer 4. The anti-reflective laminates 1A to 1D exhibit superior abrasion resistance and hardness due to the improved adhesion provided by this hard coat layer 3.

[0021] The hard coat layer 3 consists of a resin cured body. Specifically, a resin cured body obtained by polymerizing and curing polymerizable polyfunctional acrylates such as dipentaerythritol hexa(meth)acrylate, phenylglycidyl ether (meth)acrylate hexamethylene diisocyanate urethane prepolymer, phenylglycidyl ether (meth)acrylate isophorone diisocyanate urethane prepolymer, phenylglycidyl ether (meth)acrylate tolylene diisocyanate urethane prepolymer; glycerin di(meth)acrylate tolylene diisocyanate urethane oligomer, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane oligomer, glycerin di(meth)acrylate isophorone diisocyanate urethane oligomer, pentaerythritol tri(meth)acrylate tolylene diisocyanate urethane oligomer, and pentaerythritol tri(meth)acrylate isophorone diisocyanate urethane pre-oligomer is used.

[0022] In particular, to improve the adhesion between the transparent substrate 2 and the anti-reflective layer 4, as well as the hardness of the hard coat layer 3 itself, a cured resin body of the following composition is preferably used. Specifically, a curable composition preferably used for forming the hard coat layer 3 consists of a cured body of a curable composition comprising (A) a polymerizable monomer, (B-1) silica fine particles, (C) a silane coupling compound or its hydrolysate, and (D) a metal chelate compound, wherein the composition is 100 parts by mass of (A) polymerizable monomer (1000 to 2000 parts by mass) and (B-1) silica fine particles (300 to 500 parts by mass) for a total of 100 parts by mass of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound (100 to 99 parts by mass).

[0023] <(A) Polymerizable monomers> Polymerizable monomers are components that form the base material of the hard coat layer 3 after polymerization and curing, but they are used in combination with other essential components, and there are no particular restrictions on their type. Examples of polymerizable monomers include the following compounds.

[0024] Monofunctional acrylate monomers include acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, lauryl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0025] Examples of difunctional acrylate monomers include difunctional acrylate compounds such as ethylene glycol (meth)acrylate, or difunctional urethane acrylate compounds obtained by a polyaddition reaction between a diisocyanate compound and a (meth)acrylate compound having multiple hydroxyl groups, and in which the number of (meth)acryloyl groups is controlled to two. Conventional known methods can be used without any limitations for the conditions of the polymerization addition reaction and the raw materials.

[0026] 3-4 functional acrylate monomers include 3-4 functional acrylate compounds such as pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and trimethylolpropane tri(meth)acrylate, or 3-4 functional urethane acrylate compounds obtained by polyaddition reactions of diisocyanate compounds with (meth)acrylate compounds having multiple hydroxyl groups, and in which the number of (meth)acryloyl groups is controlled to 3-4. Conventional known methods can be used without any limitations for the conditions of the polymerization addition reaction and the raw materials.

[0027] Hexafunctional acrylate monomers include (meth)acrylate compounds having six (meth)acryloyl groups, such as dipentaerythritol hexaacrylate. Preferably, a hexafunctional urethane acrylate compound obtained by a polyaddition reaction between a diisocyanate compound and a (meth)acrylate compound having multiple hydroxyl groups, and in which the number of (meth)acryloyl groups is controlled to six, is preferred for forming a dense layer with high surface hardness. Conventional known methods can be used without any limitations for the conditions of the polymerization addition reaction and the raw materials.

[0028] The polymerizable monomers mentioned above are commercially available and therefore generally accessible. Various urethane acrylate monomers are also commercially available from companies such as Shin-Nakamura Chemical Industry Co., Ltd., Kyoeisha Chemical Co., Ltd., KSM Co., Ltd., Negami Kogyo Co., Ltd., Nippon Synthetic Chemical Industry Co., Ltd., Tomoe Kogyo Co., Ltd., and Toyo Chemicals Co., Ltd.

[0029] The polymerizable monomers described above are used in combination as appropriate, taking into consideration not only the hardness of the cured product after curing, but also impact resistance, adhesion to the anti-reflective layer 4, and the viscosity of the monomers. In particular, when (A) the polymerizable monomer is a mixed composition containing 5.0 to 15.0 parts by mass of a 3- to 4-functional urethane acrylate monomer and 5.0 to 10.0 parts by mass of a 2-functional acrylate monomer per 100 parts by mass of a 6- or more-functional urethane acrylate monomer, it is highly preferable in terms of adhesion to the anti-reflective layer 4, light resistance, flexibility, and hardness.

[0030] <(B-1) Silica microparticles> Silica microparticles are particles that contribute to improved adhesion and coating properties. While the properties of silica microparticles are not particularly limited, they are typically spherical, with an average particle diameter of 5-50 nm and a refractive index of 1.44-1.50. When the average particle diameter falls outside this range, crack resistance tends to deteriorate.

[0031] Silica nanoparticles are single-particle, dense, non-hollow particles without internal cavities, and typically have a density of 1.9 g / cm³. 3 That concludes the explanation. Since silica nanoparticles are publicly known and commercially available, one can simply select and use a commercially available product that satisfies the above average particle size and refractive index. Silica nanoparticles are usually supplied dispersed in a solvent. The solvent inevitably becomes mixed into the solution of the curable composition for forming the hard coat layer 3 and behaves like other solvents.

[0032] <(C) Silane coupling compound or its hydrolysate> Silane coupling compounds or their hydrolysates undergo hydrolysis themselves to form a dense siliceous film. Known silane coupling compounds can be used without limitation. Specifically, examples include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane.

[0033] Depending on the type, silane coupling compounds are preferably pre-hydrolyzed with a dilute acid or the like to improve their solubility in water or solvents. There are no particular restrictions on the pre-hydrolysis method; however, a common method involves hydrolyzing a portion of the compound using an acid catalyst such as acetic acid.

[0034] <(D) Metal Chelate Compounds> The metal chelate compound is a component that functions as a crosslinking agent, and it contributes to making the formed hard coat layer 3 a denser hardened body.

[0035] Metal chelate compounds are compounds in which a chelating agent, typically a bidentate ligand, is coordinated to a metal ion such as a tetravalent titanium metal ion, a tetravalent zirconium metal ion, or a trivalent aluminum metal ion. Specifically, titanium chelate compounds such as triethoxy-mono(acetylacetonate)titanium, diethoxy-bis(acetylacetonate)titanium, monoethoxy-tris(acetylacetonate)titanium, tetrakis(acetylacetonate)titanium, triethoxy-mono(ethylacetoacetate)titanium, diethoxy-bis(ethylacetoacetate)titanium, monoethoxy-tris(ethylacetoacetate)titanium, mono(acetylacetonate)tris(ethylacetoacetate)titanium, bis(acetylacetonate)bis(ethylacetoacetate)titanium, tris(acetylacetonate)mono(ethylacetoacetate)titanium; triethoxy-mono(acetylacetonate)zirconium, diethoxy-bis(acetylacetonate)zirconium, monoethoxy-tris(acetylacetonate)zirconium, tetrakis(acetylacetonate)zirconium, Examples include zirconium chelate compounds such as triethoxy mono(ethyl acetate) zirconium, diethoxy bis(ethyl acetate) zirconium, monoethoxy tris(ethyl acetate) zirconium, tetrakis(ethyl acetate) zirconium, mono(acetylacetonate) tris(ethyl acetate) zirconium, bis(acetylacetonate) bis(ethyl acetate) zirconium, and tris(acetylacetonate) mono(ethyl acetate) zirconium; and aluminum chelate compounds such as diethoxy mono(acetylacetonate) aluminum, monoethoxy bis(acetylacetonate) aluminum, di-i-propoxy mono(acetylacetonate) aluminum, monoethoxy bis(ethyl acetate) aluminum, and diethoxy mono(ethyl acetate) aluminum.

[0036] The above curable composition preferably contains (A) a polymerizable monomer, (B-1) silica fine particles, (C) a silane coupling compound or its hydrolysate, and (D) a metal chelate compound in the following specific ratios.

[0037] In other words, it is preferable that (A) the polymerizable monomer be in an amount of 1,000 to 2,000 parts by mass per 100 parts by mass of the total amount of (C) the silane coupling compound or its hydrolysate and (D) the metal chelate compound. If the amount is less than 1,000 parts by mass, the formation of the hard coat layer 3 will be insufficient, and if it exceeds 2,000 parts by mass, it will result in a poor appearance.

[0038] On the other hand, (B-1) silica fine particles are preferably present in amounts of 300 to 500 parts by mass per 100 parts by mass of the total amount of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound. If the amount is less than 300 parts by mass, the appearance will be unsatisfactory, and if it exceeds 500 parts by mass, the impact resistance tends to deteriorate.

[0039] On the other hand, the amount of (C) silane coupling compound or its hydrolysate is preferably 95 to 99 parts by mass per 100 parts by mass of the total amount with (D) metal chelate compound. If the amount is less than 95 parts by mass, the film adhesion will be poor, and if it exceeds 99 parts by mass, the smoothness of the hard coat layer tends to be poor.

[0040] On the other hand, the amount of (D) metal chelate compound is preferably 1 to 5 parts by mass per 100 parts by mass of the total amount of (C) silane coupling compound or its hydrolysate. If the amount is outside this range, the adhesion between the hard coat layer 3 and the anti-reflective layer 4 formed on top of the hard coat layer 3 will be poor, or the density will be insufficient, and the hardness will tend to decrease.

[0041] The above curable composition may contain any additives for viscosity adjustment or ease of application, provided that these additives do not impair its original purpose. Conventionally known ultraviolet absorbers may also be added. In particular, to cure the above curable composition on a transparent substrate 2 to form a hard coat layer 3, a thermal polymerization initiator or photopolymerization initiator is usually added in a catalytic amount, typically 0.01 to 20% by mass based on the total solid content in the composition. This polymerization initiator does not essentially affect the properties of the hard coat layer 3 obtained by curing the curable composition.

[0042] <Formation of the hard coat layer> Each of the above essential components, and any optional components, is typically mixed and stirred with the following solvents in any order at around room temperature to form a solution of the curable composition. After applying this solution onto the transparent substrate 2, the solvent is dried at 50°C or higher, and then cured by ultraviolet irradiation to form a hard coat layer 3. The thickness of the hard coat layer 3 is set to a range of 1 to 100 μm, preferably 1 to 30 μm, and more preferably 1 to 10 μm.

[0043] Suitable solvents include alcohol-based solvents such as ethyl alcohol and (iso)propyl alcohol; aromatic solvents such as toluene and xylene; acetic acid ester solvents such as (iso)butyl acetate and (iso)propyl acetate; ketone-based solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK); and hydrocarbon solvents such as n-hexane and n-heptane. These solvents are removed by evaporation during the formation of the hard coat layer.

[0044] The method for coating the transparent substrate 2 with the solution is not particularly limited, and methods such as dip coating, roll coating, die coating, flow coating, and spray coating can be used. However, the dip coating method is preferred from the viewpoint of appearance quality and layer thickness control.

[0045] When a glass substrate is used for the transparent substrate 2, the hard coat layer 3 is unnecessary, and the anti-reflective layer 4, described later, should be laminated instead.

[0046] [Anti-reflection layer] In this embodiment, the anti-reflective laminates 1A to 1C have an anti-reflective layer 4 directly laminated on a hard coat layer 3 laminated on a transparent substrate 2. In this embodiment, the anti-reflective laminate 1D has an anti-glare layer 7 laminated on the hard coat layer 3, and the anti-reflective layer 4 laminated on top of that. The anti-reflective layer 4 has at least a low refractive index layer 41 on the overcoat layer 5 side. The low refractive index layer 41 is made of a cured film of a composition mainly composed of alkoxysilane, with a refractive index of 1.25 to 1.40 and a thickness of 50 to 200 nm.

[0047] If the refractive index and thickness of the low refractive index layer 41 fall outside this range, it will not function as an anti-reflective layer 4. If the anti-reflective layer 4 consists of multiple layers, the low refractive index layer 41 is located on the outermost layer (viewing side) of the anti-reflective layer 4.

[0048] <(B-2) Hollow silica microparticles> The low refractive index layer 41 contains (B-2) hollow silica nanoparticles as particles that control its refractive index. The hollow silica nanoparticles of the low refractive index layer 41 are hollow inside, with a porosity of 20-70%, preferably 30-50%, a refractive index of typically 1.30 or less, and an average particle diameter of 10-150 nm. It is essential to select a particle diameter smaller than the thickness of the low refractive index layer 41.

[0049] If the average particle size falls outside the above range, not only will the reflectivity decrease and the haze rate increase, but even if protective layer 6 is provided, the abrasion resistance will not improve. A more preferable average particle size is 50-100 nm, and an even more preferable average particle size is 50-70 nm.

[0050] The hollow silica nanoparticles described above can be selected from commercially available products that meet the above average particle size requirement. Since these hollow silica nanoparticles are usually provided dispersed in a solvent, this solvent behaves in the same way as in the case of the (B-1) silica nanoparticles described above.

[0051] <Composition for forming a low refractive index layer> The composition for forming the low refractive index layer 41 is a curable composition comprising the above-mentioned (B-2) hollow silica fine particles, (C) silane coupling compound or its hydrolysate, and (D) metal chelate compound as essential components. Although (B-2) hollow silica fine particles are essential components, the composition may further contain the above-mentioned (B-1) silica fine particles.

[0052] Furthermore, the (C) silane coupling compound or its hydrolysate and (D) metal chelate compound in the composition for forming the low refractive index layer 41 are the same as those exemplified in the hard coat layer 3 described above.

[0053] In order to exhibit excellent abrasion resistance in addition to anti-reflective properties, it is important that the anti-reflective laminates 1A to 1D of this embodiment have the following compositions.

[0054] In other words, (B-2) hollow silica fine particles are preferably present in amounts of 50 to 200 parts by mass per 100 parts by mass of the total amount of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound. If the amount is less than 50 parts by mass, a low refractive index cannot be achieved, and if it exceeds 200 parts by mass, the wear resistance decreases. If (B-1) is further included, it is preferable to blend it in an amount of 120 parts by mass or less per 100 parts by mass of the total amount of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound.

[0055] On the other hand, (C) the silane coupling compound or its hydrolysate and (D) the metal chelate compound are preferably used in a mass ratio of 90:10 to 98:2 (100 parts by mass in total). If the mixing ratio of the two does not meet this numerical range, the layer strength of the low refractive index layer 41 will decrease, coating defects will occur, and the basic layer characteristics will not be exhibited, resulting in the low refractive index layer 41 not functioning properly.

[0056] In addition to the essential components mentioned above, the composition for forming the low refractive index layer 41 may contain tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane to improve adhesion to the transparent substrate 2 and to densify and increase the strength of the hard coat layer 3.

[0057] Furthermore, in order to promote the hydrolysis and condensation of (C) silane coupling compounds or their hydrolysates or the tetraalkoxysilicon compounds, an appropriate amount of an acidic aqueous solution, such as an aqueous hydrochloric acid solution, can be added to the composition for forming the low refractive index layer 41.

[0058] <Formation of a low refractive index layer> The low refractive index layer 41 is formed in the same manner as the hard coat layer 3. A solution of the composition for forming the low refractive index layer 41 is applied to the hard coat layer 3, which is a cured body, dried, and then heated and cured at 60 to 135°C. The thickness of the low refractive index layer 41 is usually set in the range of 50 to 200 nm from the viewpoint of anti-reflective performance.

[0059] Furthermore, if the anti-reflective layer 4 consists of two layers, a medium refractive index layer 42 and a low refractive index layer 41, the medium refractive index layer 42 is first formed on the hard coat layer 3, and then the low refractive index layer 41 is formed on top of this medium refractive index layer 42.

[0060] Furthermore, if the anti-reflective layer 4 consists of three layers: a medium refractive index layer 42, a high refractive index layer 43, and a low refractive index layer 41, then the medium refractive index layer 42 is first formed on the hard coat layer 3, followed by the high refractive index layer 43 being formed on top of this medium refractive index layer, and then the low refractive index layer 41 being formed on top of this high refractive index layer 43.

[0061] Furthermore, if the anti-reflective layer 4 consists of four layers: a medium-low refractive index layer 44, a medium refractive index layer 42, a high refractive index layer 43, and a low refractive index layer 41, then the medium-low refractive index layer 44 is first formed on the hard coat layer 3, followed by the medium refractive index layer 42, then the high refractive index layer 43 is formed on top of the medium refractive index layer 42, and finally the low refractive index layer 41 is formed on top of the high refractive index layer 43.

[0062] <Intermediate refractive index layer> The medium refractive index layer 42 is a layer with a higher refractive index than the low refractive index layer 41, which is provided on the transparent substrate 2 side of the low refractive index layer 41, in order to further enhance the anti-reflective effect of the anti-reflective layer 4.

[0063] The intermediate refractive index layer 42 preferably has a refractive index of 1.50 to 1.75 and a thickness of 50 to 200 nm.

[0064] <Composition for forming the intermediate refractive index layer> The composition for forming the intermediate refractive index layer 42 is a curable composition containing 100 parts by mass of (E) metal oxide particles in a total of 70 to 99 parts by mass of (C) silane coupling compound or its hydrolysate and 30 to 1 part by mass of (D) metal chelate compound. The composition for forming the intermediate refractive index layer 42 may also optionally contain (F) organic-inorganic composite compound, as described later.

[0065] <(E) Metal oxide particles> Metal oxide particles are included to satisfy the requirement that the refractive index of the intermediate refractive index layer 42 be between 1.50 and 1.75. The metal oxide particles have an average particle diameter of 10 to 100 nm and a refractive index between 1.70 and 2.80.

[0066] Examples of metal oxide particles used include zirconium oxide particles (refractive index = 2.40); composite zirconium metal oxide particles obtained by molecularly compounding zirconium oxide with other oxides such as silicon oxide to adjust the refractive index; titanium oxide particles (refractive index = 2.71); composite titanium metal oxide particles obtained by molecularly compounding titanium oxide with other oxides such as silicon oxide or zirconium oxide to adjust the refractive index; and silica particles (refractive index = 1.55). These metal oxide particles are selected or appropriately combined to create layers with the desired refractive index. Such particles are publicly known and commercially available.

[0067] <(F) Organic / inorganic composite compound> Organic-inorganic composite compounds are used to improve the adhesion and alkali resistance of the intermediate refractive index layer 42. Organic-inorganic composite compounds are compounds that combine the advantages of organic and inorganic materials, with no glass transition temperature (Tg) like glass, due to crosslinking of epoxy groups between compounds and the generation of silica particles by sol-gel curing of alkoxysilyl groups. When used in compositions for forming intermediate refractive index compounds, it is preferable to blend them in an amount of 175 parts by mass or less per 100 parts by mass of the total of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound (70 to 99 parts by mass) and 30 to 1 part by mass.

[0068] Organic-inorganic composite compounds exist in a variety of types. For example, composite compounds in which an alkoxysilyl group is bonded to bisphenol A epoxy compounds, novolacphenol compounds, or polyamic acid compounds are examples of such compounds.

[0069] Among these, a composite compound in which an alkoxysilyl group is bonded to a bisphenol A type epoxy compound is preferably used as an organic-inorganic composite compound, given that it does not impair the hardness of the intermediate refractive index layer 42 and is readily available.

[0070] <Formation of a medium refractive index layer> The formation of the intermediate refractive index layer 42 is carried out in the same manner as the formation of the low refractive index layer 41. The thickness of the intermediate refractive index layer 42 is set in the range of 50 to 200 nm from the viewpoint of anti-reflective performance.

[0071] <High refractive index layer> The high refractive index layer 43 is a layer with a higher refractive index than the medium refractive index layer 42, and is provided between the low refractive index layer 41 and the medium refractive index layer 42 in order to further enhance the anti-reflective effect of the anti-reflective layer 4.

[0072] The high refractive index layer 43 preferably has a refractive index of 1.60 to 2.00 and a thickness of 50 to 200 nm.

[0073] <Composition for forming a high refractive index layer> The composition for forming the high refractive index layer 43 is a curable composition containing 100 parts by mass of (E) metal oxide particles in a total of 100 parts by mass of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound (75 to 95 parts by mass and 25 to 5 parts by mass).

[0074] (E) The metal oxide particles are selected from the above metal oxide particles, or used in appropriate combinations, so that the refractive index of the high refractive index layer 43 is 1.60 to 2.00.

[0075] <Formation of a high refractive index layer> The high refractive index layer 43 is formed in the same manner as the low refractive index layer 41 and the medium refractive index layer 42. The thickness of the high refractive index layer 43 is set in the range of 50 to 200 nm from the viewpoint of anti-reflective performance.

[0076] <Medium-low refractive index layer> The medium-low refractive index layer 44 is a layer with a lower refractive index than the medium refractive index layer 42, provided between the hard coat layer 3 and the medium refractive index layer 42, in order to further enhance the anti-reflective effect of the anti-reflective layer 4.

[0077] The intermediate-low refractive index layer 44 preferably has a refractive index of 1.30 to 1.50 and a thickness of 100 to 300 nm. The refractive index of the intermediate-low refractive index layer 44 is set to be higher than the refractive anomaly of the low refractive index layer 41.

[0078] <Composition for forming medium- and low refractive index layers> The composition for forming the medium-low refractive index layer 44 is a curable composition containing 55 to 175 parts by mass of (B-1) silica fine particles and 25 to 175 parts by mass of (B-2) hollow silica fine particles, in a total of 100 parts by mass of 90 to 98 parts by mass of (C) silane coupling compound or its hydrolysate and 10 to 2 parts by mass of (D) metal chelate compound. The composition for forming the medium-low refractive index layer 44 may also optionally contain (F) organic-inorganic composite compound in an amount of 100 parts by mass or less.

[0079] <Formation of a medium-to-low refractive index layer> The formation of the intermediate-low refractive index layer 44 is carried out in the same manner as the formation of the low refractive index layer 41, the intermediate refractive index layer 42, and the high refractive index layer 43. The thickness of the intermediate-low refractive index layer 44 is set in the range of 100 to 300 nm from the viewpoint of anti-reflective performance.

[0080] [Overcoat layer] The overcoat layer 5 is a layer positioned on the outermost surface of the anti-reflective laminates 1A to 1D of this embodiment, and is provided to exhibit abrasion resistance and a high degree of anti-fouling properties.

[0081] The overcoat layer 5 is a non-fluorine-based antifouling agent consisting of a cured silicon-based compound. Preferably, the silicon-based compound consists of at least one selected from polysiloxane, silane compound, and organosilazane. The thickness of the overcoat layer 5 is typically set in the range of 3 to 15 nm to achieve its function. Additionally, optional components such as a curing agent or leveling agent may be added.

[0082] <Formation of the overcoat layer> The preparation of the curable composition for forming the overcoat layer 5 and the method for forming the overcoat layer 5 can be carried out in the same manner as for forming the anti-reflective layer 4 described above. The thickness of the overcoat layer 5 is set to a range of 3 to 15 nm, preferably 5 to 13 nm, and more preferably 5 to 10 nm. If it is less than 3 nm, it will not function as the overcoat layer 5, and if it exceeds 15 nm, the reflectivity will increase and the anti-reflective performance will decrease.

[0083] Furthermore, it is preferable that the overcoat layer 5 has an evaluation of 0 or 1 in the adhesion test (cross-cut method) of "JIS K 5600-5-6". This makes it possible to obtain sufficient adhesion and abrasion resistance as the outermost layer of the anti-reflective laminates 1A to 1D of this embodiment.

[0084] The overcoat layer 5 preferably has a water contact angle of 100° or more. If the water contact angle is less than 100°, the stain resistance will be insufficient.

[0085] [Protective layer] The protective layer 6 is an additional layer added to the anti-reflective laminates 1B to 1D of this embodiment to provide abrasion resistance, and the shape, particle size, and content of the silica fine particles used, as well as the layer thickness, are important requirements.

[0086] The refractive index of the protective layer 6 is preferably 1.45 to 1.50. If this range is not satisfied, the anti-reflective performance will decrease.

[0087] The thickness of the protective layer 6 is preferably 10 to 15 nm. If it is less than 10 nm, it will not function as a protective layer 6, and if it exceeds 15 nm, the reflectivity will increase and the anti-reflective performance will decrease.

[0088] <Composition for forming a protective layer> A suitable forming composition for forming the protective layer 6 is a total of 100 parts by mass of (C) silane coupling compound or hydrolysate thereof and (D) metal chelate compound (90 to 98 parts by mass), with (B-3) spherical silica fine particles in a ratio of 7.5 to 35 parts by mass.

[0089] <(B-3) Spherical silica microparticles> The silica fine particles of the protective layer 6 are preferably spherical and have an average particle diameter of 10 nm or less. If this condition is not met, even if the protective layer 6 is provided, the overcoat layer 5 will not be applied smoothly, and high abrasion resistance will not be achieved. Although there is no particular lower limit to the average particle diameter of the silica fine particles, it is preferable that it be 5 nm or more for ease of availability.

[0090] Silica nanoparticles are single-particle, dense, non-hollow spherical particles without internal cavities. They typically have a particle size of 5-10 nm and a density of 1.9 g / cm³. 3 That concludes the explanation. Since silica nanoparticles are publicly known and commercially available, one can simply select and use a commercially available product that satisfies the above average particle size and refractive index. Silica nanoparticles are usually supplied dispersed in a solvent. The solvent inevitably becomes mixed into the curable composition solution for forming the protective layer 6 and behaves like any other solvent.

[0091] The amount of silica fine particles is preferably 7.5 to 35 parts by mass per 100 parts by mass of the total of (C) silane coupling compound or its hydrolysate and (D) metal chelate compound. If the amount is less than 7.5 parts by mass, the refractive index of the protective layer 6 will increase, the abrasion resistance effect will not be achieved, and the film-forming ability will decrease, resulting in an inability to form a uniform protective layer 6 on the anti-reflective layer 4. On the other hand, if the amount exceeds 35 parts by mass, the protective layer 6 will become brittle and the appearance will be poor.

[0092] (C) Silane coupling compounds or their hydrolysates and (D) Metal chelate compounds can be used without limitation as those exemplified in the hard coat layer 3 described above.

[0093] The preparation of the curable composition for forming the protective layer 6 and the method for forming the protective layer 6 may be carried out in the same manner as the anti-reflective layer 4 described above.

[0094] [Anti-glare layer] The anti-glare layer 7 is a layer positioned between the hard coat layer 3 and the anti-reflective layer 4. It is a layer that provides surface irregularities to disperse and diffuse light in order to suppress glare caused by diffuse reflection and diffusion of light on the surface of the anti-reflective laminate 1D. The thickness of the anti-glare layer 7 is 100 to 500 nm.

[0095] <Composition for forming an anti-glare layer> A suitable composition for forming the anti-glare layer 7 is (A) 100 parts by mass of polymerizable monomer, (B-4) inorganic particles 0.1 to 15 parts by mass, and (D) metal chelate compound 0.1 to 1 part by mass. (B-4) inorganic particles are essential components, but may also be present in (B-1) silica fine particles.

[0096] <(B-4) Inorganic particles> To achieve anti-glare properties, it is necessary to use inorganic particles with an average particle diameter of 500-700 nm. Below 500 nm, anti-glare properties are not achieved, and above 700 nm, a white haze occurs, resulting in an undesirable appearance.

[0097] Since the surface properties depend on the average particle size of the particles used, the chemical composition and properties are not particularly limited as long as the average particle size of the particles is within the above range. Specifically, examples include inorganic oxide particles such as silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and zinc oxide; nitride particles such as aluminum nitride and boron nitride; and inorganic salt particles such as magnesium sulfate and calcium carbonate.

[0098] Among inorganic particles, silica particles are particularly suitable because they do not cause chemical degradation of the anti-glare layer 7 or the anti-reflective layer 4, and because they are readily available. Silica particles have the same chemical composition and structure as silica fine particles, but differ significantly in that their average particle size is 500-700 nm. Silica particles are well known and are usually commercially available in a dispersed state in a solvent. For the purpose of improving coating properties, (B-1) silica fine particles may be added in an amount of 45 parts by mass or less per 100 parts by mass of (A) polymerizable monomer.

[0099] <Formation of an anti-glare layer> The anti-glare layer 7 is formed in the same manner as the hard coat layer 3 described above. The thickness of the anti-glare layer 7 is usually set in the range of 100 to 500 nm from the viewpoint of anti-glare performance.

[0100] In the anti-reflective laminates 1A to 1D of this embodiment, having the above-described configuration, by placing the overcoat layer 5, which is made of the non-fluorine-based antifouling agent described above, on the outermost surface, it is possible to obtain excellent antifouling properties, adhesion, and abrasion resistance of the overcoat layer 5 without using a fluorine-based antifouling agent.

[0101] It should be noted that the present invention is not necessarily limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0102] The anti-reflective laminates 1A to 1D described above are not necessarily limited to those with the layer configurations described above. For example, an adhesive layer made of an acrylic, rubber, or silicone adhesive may be provided on the back surface of the transparent substrate 2. Alternatively, the layers described above may be laminated on both sides of the transparent substrate 2.

[0103] Furthermore, there are no limitations on the display devices that use the anti-reflective laminate of the present invention. Examples include general display devices such as CRTs, LCDs, and PDPs, as well as other devices such as automobile instrument panels, center information displays (CIDs), head-up displays, car navigation systems, personal computers, picture frames, photo frames, smartphones, tablets, ATMs, automatic ticket vending machines, single-lens reflex cameras, medical panels, and touch panels used in car navigation systems. [Examples]

[0104] The effects of the present invention will be made clearer by the following examples. However, the present invention is not limited to the following examples and can be modified as appropriate without altering its essence. The various components and abbreviations used in the following examples and comparative examples are as follows.

[0105] <(A) Polymerizable monomers> [Hexafunctional urethane (meth)acrylate] ac-6: Pentaerythritol triacrylate hexamethylene diisocyanate Retan Prepolymer [Bifunctional (meth)acrylate compounds] AC-2: Triethylene glycol diacrylate [Trifunctional (meth)acrylate compounds] ac-3: Polyester-based urethane acrylate <(B) Silica microparticle sol> sp-1: Solid spherical particle, average particle size = 7 nm, refractive index = 1.46 IPA dispersion, solid part: 20% by mass sp-2: Hollow particle, average particle diameter = 60 nm, refractive index = 1.30 IPA dispersion, solid part: 20% by mass <(C) Silane coupling compound> γ-GPS:γ-glycidoxypropyltrimethoxysilane <(D) Metal Chelate Compounds> ATAA: Aluminum tris(acetylacetonate) <(E) Metal oxide sol> z-1: Zirconia particles, average particle size = 60 nm, refractive index = 2.42 PGM (1-methoxy-2-propanol) dispersion, solids: 53% by mass z-2: Zirconia particles, average particle size = 30 nm, refractive index = 2.40 BuOH / EtOH dispersion, solid part: 15% by mass <(F) Organic / inorganic composite compound> sep: Silane-modified epoxy compound DMDG (Diethylene Glycol Dimethyl Ether) Dispersion <Other ingredients> [Photopolymerization initiator] pi-1: 1-Hydroxycyclohexylphenyl ketone pi-2:2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one [UV absorber] UV: Benzotriazole-based UV absorber [Hydrolysis catalyst] HCl: 0.05N hydrochloric acid aqueous solution [Non-fluorine-based antifouling agent] pf-1: Modified polydimethylsiloxane pf-2: Monomethyltriisocyanate silane Ethyl acetate dispersion, solids: 11% by mass pf-3: Organosilazane pf-4: Long-chain fatty acid-containing acrylic polymer IPA / methylcyclohexane dispersion, solid portion 19.8% by mass pf-5: Silicone-modified acrylic polymer MEK / MIBK dispersion, solid part: 33% by mass [organic solvent] IPA: (Iso)propyl alcohol MIBK: Methyl isobutyl ketone SBAC: Dibutyl acetate NPA: n-propyl alcohol Ethacol: A mixture of ethyl alcohol and (iso)propyl alcohol.

[0106] (Example 1) In Example 1, an anti-reflective laminate was created using the layer-forming coating liquids shown in Table 1 below. First, a 1 mm thick transparent acrylic substrate was prepared, and the transparent substrate was dipped in the hard coat-forming coating liquid (HC-1). The substrate was dried at 60°C for 8 minutes and cured by ultraviolet irradiation to form a 1.7 μm thick hard coat layer on the transparent substrate.

[0107] Next, a transparent substrate was dip-coated with the low refractive index layer forming solution (l-1) shown in Table 1 below, and heated at 90°C for 15 minutes to form a low refractive index layer with a refractive index of 1.37 and a thickness of 100 nm.

[0108] Next, a transparent substrate was dip-coated with the overcoat layer forming solution (OC-1) shown in Table 1 below, and heated at 90°C for 5 hours to form a 5 nm overcoat layer. This produced the anti-reflective laminate of Example 1.

[0109] (Example 2) In Example 2, an anti-reflective laminate of Example 2 was fabricated in the same manner as in Example 1, except that an overcoat layer consisting of monomethyltriisocyanate silane with a thickness of 5 nm was formed using the overcoat forming solution (OC-2) shown in Table 1 below.

[0110] (Example 3) In Example 3, an anti-reflective laminate of Example 3 was fabricated in the same manner as in Example 1, except that an overcoat layer made of organosilazane with a thickness of 5 nm was formed using the overcoat forming solution (OC-3) shown in Table 1 below.

[0111] (Comparative Example 1) In Comparative Example 1, an anti-reflective laminate of Comparative Example 1 was prepared in the same manner as in Example 1, except that an overcoat layer made of a long-chain fatty acid-containing acrylic polymer with a thickness of 5 nm was formed using the overcoat-forming coating liquid (OC-4) shown in Table 2 below.

[0112] (Comparative Example 2) In Comparative Example 2, an anti-reflective laminate of Comparative Example 2 was fabricated in the same manner as in Example 1, except that an overcoat layer made of a silicone-modified acrylic polymer with a thickness of 5 nm was formed using the overcoat forming coating liquid (OC-5) shown in Table 2 below.

[0113] [Table 1]

[0114] [Table 2]

[0115] (Example 4) In Example 4, an anti-reflective laminate was prepared using the layer-forming coating liquids shown in Table 3 below. First, a hard coat layer 3 was formed on a transparent substrate in the same manner as in Example 1. Then, the transparent substrate was dip-coated with the medium refractive index layer-forming coating liquid (m-1), and heated at 90°C for 40 minutes to form a medium refractive index layer 42 with a refractive index of 1.64 and a thickness of 75 nm.

[0116] Next, the transparent substrate was dip-coated with a high refractive index layer forming solution (h-1) and heated at 70°C for 40 minutes to form a high refractive index layer 43 with a refractive index of 1.77 and a thickness of 70 nm. Then, the transparent substrate was dip-coated with a low refractive index layer forming solution (l-2) and heated at 70°C for 15 minutes to form a low refractive index layer 41 with a refractive index of 1.35 and a thickness of 75 nm.

[0117] Next, a transparent substrate was dip-coated with a protective layer 6 forming solution (CV-1), and heated at 90°C for 15 minutes to form a protective layer 6 with a refractive index of 1.50 and a thickness of 15 nm.

[0118] Next, using OC-1, an overcoat layer 5 was formed in the same manner as in Example 1. This produced the anti-reflective laminate of Example 4.

[0119] [Table 3]

[0120] Then, evaluation tests were conducted on the anti-reflective laminates of Examples 1-4 and Comparative Examples 1-2 for water contact angle, stain resistance, abrasion resistance, and adhesion. The evaluation results are summarized in Table 4 below.

[0121] [Table 4]

[0122] (water contact angle) For the water contact angle, we used "DMs-401" manufactured by Kyowa Interface Chemical Co., Ltd. to measure the water contact angle on the surface of the anti-reflective laminate under constant temperature and humidity conditions using the droplet method.

[0123] (Stain-resistant) To assess stain resistance, a line approximately 2 mm wide was drawn on the surface of the anti-reflective laminate using Pilot's oil-based marker "M-10EF-B," and the condition after wiping with tissue paper was visually observed. The evaluation is as follows: ○: No magic ink residue remains. ×: Magic ink remains.

[0124] (Abrasion resistance) For abrasion resistance, Kanakin No. 3 conforming to "JIS L 0803" was tested under a load of 500g / cm². 2 The surface condition of the anti-reflective laminate was observed visually after 200 back-and-forth movements over a 40mm distance. The evaluation is as follows: ○: No damage is visible. ×: Damage is visible.

[0125] (Adhesion) Adhesion was evaluated on a 6-point scale from 0 to 5 using the cross-cut method in accordance with "JIS K 5600-5-6" (please refer to the above JIS for the evaluation criteria from 0 to 5).

[0126] As shown in Table 4, the anti-reflective laminates of Examples 1 to 4 showed better results in water contact angle, antifouling properties, abrasion resistance, and adhesion evaluation tests compared to the anti-reflective laminates of Comparative Examples 1 to 2. [Explanation of symbols]

[0127] 1A-1D…Anti-reflective laminate 2…Transparent substrate 3…Hard coat layer 4…Anti-reflective layer 5…Overcoat layer 6…Protective layer 7…Anti-glare layer 41…Low refractive index layer 42…Medium refractive index layer 43…High refractive index layer 44…Medium-low refractive index layer

Claims

1. An anti-reflective laminate is formed by laminating a hard coat layer, an anti-reflective layer, and an overcoat layer in this order on a transparent substrate. The anti-reflective layer has at least a low refractive index layer on the overcoat layer side, The low refractive index layer consists of a cured film of a composition mainly composed of alkoxysilane. The anti-reflective laminate is characterized in that the overcoat layer is made of a cured silicon-based compound and has a water contact angle of 100° or more.

2. The anti-reflective laminate according to claim 1, characterized in that the evaluation in the adhesion test (cross-cut method) of "JIS K 5600-5-6" is 0 or 1.

3. The anti-reflective laminate according to claim 1, characterized in that the silicon-based compound comprises at least one selected from polysiloxane, silane compound, and organosilazane.

4. The anti-reflective laminate according to claim 1, characterized in that the low refractive index layer consists of a cured film of a composition mainly comprising alkoxysilane, hollow silica fine particles, and a metal chelate compound.

5. A protective layer is provided between the anti-reflective layer and the overcoat layer. The anti-reflective laminate according to claim 1, characterized in that the protective layer consists of a cured film of a composition mainly composed of alkoxysilane, spherical silica fine particles with a particle size of 5 to 10 nm, and a metal chelate compound.

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