JP3776978B2 - Antireflection film and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes various types of displays such as word processors, computers, televisions, plasma display panels, the surfaces of polarizing plates used in liquid crystal display devices, sunglasses lenses made of transparent plastics, prescription eyeglass lenses, optical lenses such as finder lenses for cameras, The present invention relates to an antireflection film excellent in antireflection on the surfaces of various instrument covers, window glasses of automobiles, trains, etc., and a method for producing the same.
[0002]
[Prior art]
Conventionally, transparent substrates such as glass and plastic have been used for displays such as curved mirrors, rearview mirrors, goggles, window glass, personal computers, word processors, plasma displays, and other various commercial displays. When observing visual information such as objects, characters, figures, etc., or when observing an image from a reflective layer through a transparent substrate with a mirror, the surface of these transparent substrates is reflected by external light and the internal visual information is visible. There was a problem that it was difficult.
[0003]
As a method for preventing reflection of such a transparent substrate, conventionally, a method of applying an antireflection coating on the surface of glass or plastic, a hard coat layer as necessary on the surface of a transparent substrate such as a glass / plastic substrate, etc. MgF with a film thickness of about 0.1 μm₂And SiO₂There is a method of forming a thin film such as a vapor phase method such as vapor deposition, sputtering, or plasma CVD method.
[0004]
[Problems to be solved by the invention]
Although the functional thin film manufacturing method by the vapor phase method can obtain a high-performance and high-quality thin film, it requires precise control of the atmosphere in a high vacuum system, and is also capable of special heating or ionization. There is a problem that the production cost is inevitably increased because the generation accelerating device is required and the manufacturing apparatus is complicated and large. There is also a problem that it is difficult to increase the area of the thin film or to manufacture a complicated shape.
On the other hand, among the production methods of functional thin films by the coating method, those using the spray method have problems such as poor utilization efficiency of the coating liquid and difficulty in controlling the film forming conditions.
In addition, the method for producing a functional thin film using a coating method such as a dipping method or a screen printing method has good utilization efficiency of the film forming raw material, and is advantageous in terms of mass production and equipment cost. There is a problem that the functional thin film is inferior in function and quality as compared with a thin film obtained by a vapor phase method.
[0005]
In recent years, as a method for obtaining an excellent quality thin film by a coating method, a method in which a dispersion liquid in which inorganic or organic ultrafine particles are dispersed in an acidic and / or alkaline aqueous solution is coated on a substrate and baked has been proposed. According to this manufacturing method, it is advantageous in terms of mass production and equipment costs, but since a high-temperature baking process is required during the manufacturing process, it is impossible to form a film on a plastic substrate. The uniformity of the film is not sufficient due to the difference in the degree of shrinkage between the coating film and the coating film, and the performance is still inferior when compared with the thin film obtained by the vapor phase method. Or more) and has the disadvantage of being inferior in productivity.
Accordingly, an object of the present invention is to provide a high-function and high-quality antireflection film by a coating method advantageous in terms of mass production and equipment cost.
[0006]
[Means for Solving the Problems]
  The above object is achieved by the present invention described below. That is, the present invention provides an antireflection film in which a high refractive index hard coat layer and a low refractive index layer are laminated directly or via another layer on a transparent substrate film, wherein the low refractive index layer is R_mSi (OR ')_n(R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m + n is 4, and m and n are each an integer) and prepared by hydrolyzing a silicon alkoxide in the presence of acetic acid. , Sodium acetate or lithium acetate addedSiO ₂ The concentration is 0.1 to 10% by massSiO₂SiO formed from sol solution₂An antireflection film comprising a gel layer and a method for producing the same.
[0007]
  According to the present invention, the lower silicon alkoxide isIn the presence of acetic acidBy hydrolyzing, fine particles of several nanometers are prepared by the sol-gel method, and these ultrafine particles are dispersed., Sodium acetate or lithium acetate addedAfter the sol solution is applied on the high refractive index hard coat layer on the surface of the transparent base film, it is heat-treated at a temperature lower than the heat deformation temperature of the transparent base film, or irradiated with active energy rays to form SiO.₂By forming the gel layer, a low refractive index layer having substantially the same performance as that of the low refractive index layer obtained by the vapor phase method can be obtained, and a base material having a low thermal deformation temperature such as a plastic base material Even if is used, it is possible to form a high-performance and high-quality antireflection film.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
FIG. 1 is a diagram schematically showing a cross section of an example of the antireflection film of the present invention. The antireflection film of this example is an example in which a high refractive hard coat layer 2 and a low refractive index layer 3 are laminated on a transparent substrate film 1, and reference numeral 4 in the figure denotes an adhesive layer that is laminated as necessary. Or it is a primer layer.
FIG. 2 is an example in which the fine irregularities 5 are provided on the outermost surface in the example shown in FIG. 1 and the antireflection film is imparted with an antiglare property.
[0009]
In the present invention, the transparent base film may be any film as long as it is transparent, for example, a triacetyl cellulose film, a diacetyl cellulose film, an acetate butyrate cellulose film, a polyether sulfone film, a poly Acrylic resin films, polyurethane resin films, polyester films, polycarbonate films, polysulfone films, polyether films, trimethylpentene films, polyetherketone films, (meth) acrylonitrile films, etc. can be used. An axially stretched polyester is preferably used because it is excellent in transparency and heat resistance and has no optical anisotropy. The thickness is preferably about 8 μm to 1,000 μm.
[0010]
In the example of FIG. 1, the high refractive index hard coat layer formed on the surface of the transparent substrate film is formed of a thermosetting resin or an ionizing radiation curable resin, and the transparent substrate film is made of a thermoplastic resin. Therefore, it is preferable to use an ionizing radiation curable resin that does not require a high temperature when the coating film is cured. In the present specification, “hard coat layer” or “having a hard property” means a material having a hardness of H or higher in a pencil hardness test shown in JIS K5400. In the present invention, “high refractive index” and “low refractive index” refer to the relative refractive index between adjacent layers.
[0011]
The ionizing radiation curable resin suitable for forming the high refractive index hard coat layer is preferably one having an acrylate functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy. Resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers such as (meth) acrylates of polyfunctional compounds such as polyhydric alcohols, and ethyl (meth) acrylate as a reactive diluent , Ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and other monofunctional monomers, as well as polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene Glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Those containing a relatively large amount of acrylate or the like can be used.
Further, in order to convert the ionizing radiation curable resin into an ultraviolet curable resin, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetramethylthiuram monosulfide are used as photopolymerization initiators. In addition, thioxanthones, and n-butylamine, triethylamine, tri-n-butylphosphine, etc. can be mixed and used as a photosensitizer.
[0012]
When the high refractive index hard coat layer is formed of the above ionizing radiation curable resin alone, if the crosslink density becomes too high at the time of curing, the flexibility is lowered, and the high antireflective film is hard when the resulting antireflection film is bent. In some cases, cracks or the like are likely to enter the coat layer.
In this case, the non-reactive resin is preferably mixed with the composition for forming a high refractive index hard coat layer in an amount up to about 50% by weight in the entire composition. When there is too much addition amount of non-reactive resin, the hardness of the layer obtained may become inadequate. As this non-reactive resin, a thermoplastic resin is mainly used. In particular, when a mixture of polyester acrylate and polyurethane acrylate is used as the ionizing radiation curable resin, poly (methyl methacrylate) or poly (butyl methacrylate) can keep the coating film high in the thermoplastic resin used. it can. Moreover, in this case, since the refractive index is close to that of the main ionizing radiation curable resin, the transparency of the coating film is not impaired, and it is advantageous in terms of transparency, in particular, low haze value, high transmittance, and compatibility. .
[0013]
The refractive index of the high refractive index hard coat layer comprising the above components is usually about 1.49 to 1.51. In the example shown in FIG. 1, in order to make the high refractive index hard coat layer have a high refractive index, ultrafine particles of a high refractive index metal or metal oxide are contained in the resin composition for forming a high refractive index hard coat layer. It is preferable to add to improve the refractive index of the formed high refractive index hard coat layer to about 1.50 to 2.30. Examples of the material for making the high refractive index hard coat layer have a high refractive index include, for example, ZnO (refractive index 1.90), TiO.₂(Refractive index 2.3 to 2.7), CeO₂(Refractive index 1.95), Sb₂O_Five(Refractive index 1.71), SnO₂, ITO (refractive index 1.95), Y₂O_Three(Refractive index 1.87), La₂O_Three(Refractive index 1.95), ZrO₂(Refractive index 2.05), Al₂O_ThreeExamples thereof include fine powders such as (refractive index 1.63).
In order to further improve the refractive index of the high refractive index hard coat layer, a resin containing molecules and atoms of a high refractive index component may be used in the resin composition for forming a high refractive index hard coat layer. Examples of the molecules and atoms of the component for improving the refractive index include halogen atoms other than F, S, N, P atoms, aromatic rings, and the like.
[0014]
The high refractive index hard coat layer composed of the above components is prepared by dissolving or dispersing the above components in an appropriate solvent to form a coating solution, which is directly applied to the substrate film and cured. It can also be formed by applying it to a release film and curing it, and then transferring it to the transparent substrate film using an appropriate adhesive. The thickness of the high refractive index hard coat layer is usually preferably about 3 to 10 μm.
For curing the high refractive index hard coat layer, an ordinary method of curing an ionizing radiation curable resin, that is, a method of curing by irradiation with an electron beam or ultraviolet rays can be used. For example, in the case of electron beam curing, 50 to 1000 KeV emitted from various electron beam accelerators such as a Cockloft Walton type, a bandegraph type, a resonant transformation type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type, Preferably, an electron beam or the like having an energy of 100 to 300 KeV is used, and in the case of ultraviolet curing, ultraviolet rays emitted from light rays such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp can be used. .
[0015]
Next, on the surface of the high refractive index hard coat layer, SiO₂SiO with refractive index of 1.38 to 1.46 from sol solution₂By forming a low refractive index layer made of a gel film, the antireflection film of the present invention shown in FIG. 1 can be obtained.
SiO₂The sol can be prepared by dissolving silicon alkoxide in an organic solvent suitable for coating, adding a certain amount of water, and performing hydrolysis.
SiO₂Preferred examples of silicon alkoxides used for sol formation include R_mSi (OR ')_nWherein R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m + n is 4, and m and n are each an integer. More specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetra Pentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyl Tripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, Methyl-butoxy silane, methyl dimethoxy silane, methyl diethoxy silane, hexyl trimethoxy silane and the like.
[0016]
The silicon alkoxide is hydrolyzed by dissolving the silicon alkoxide in a suitable solvent. Examples of the solvent used include alcohols such as methyl ethyl ketone, isopropyl alcohol, methanol, ethanol, methyl isobutyl ketone, ethyl acetate and butyl acetate, ketones, esters, halogenated hydrocarbons, aromatic hydrocarbons such as toluene and xylene, Or the mixture of these is mentioned.
The alkoxide is formed in the above solvent as a result of 100% hydrolysis and condensation of the alkoxide.₂It dissolves so that it may become 0.1 weight% or more in conversion, Preferably it will be 0.1-10 weight%. SiO₂If the concentration of the sol is less than 0.1% by weight, the formed sol film cannot sufficiently exhibit the desired characteristics, while if it exceeds 10% by weight, it becomes difficult to form a transparent homogeneous film. Moreover, in this invention, if it is less than the above solid content, it is also possible to use an organic substance and an inorganic binder together.
[0017]
  Water more than the amount necessary for hydrolysis is added to this solution, and stirring is performed at a temperature of 15 to 35 ° C., preferably 22 to 28 ° C., for 0.5 to 10 hours, preferably 2 to 5 hours.
  In the above hydrolysis, TouchAs a mediumVinegaracidToAn acid can be added as an aqueous solution of about 0.001 to 20.0 N, preferably about 0.005 to 5.0 N, and water in the aqueous solution can be used as water for hydrolysis.
  SiO obtained as described above₂The sol is a colorless and transparent liquid, is a stable solution having a pot life of about 1 month, has good wettability with respect to the high refractive index hard coat layer, and is excellent in coating suitability.
[0018]
  Various additives can be added to the sol solution. Additives include curing agents that promote film formation, and these curing agents include sodium acetate, lithium acetate.IsCan be mentioned. The concentration of the organic solvent solution is about 0.01 to 0.1% by weight, and the amount added to the sol solution is SiO 2 present in the sol solution.₂Above for 100 parts by weightAcetic acidA range of about 0.1 to 1 part by weight as the salt is preferred.
[0019]
Furthermore, although the gel film finally obtained becomes a low refractive index layer of the antireflection film, it may be necessary to adjust the refractive index. For example, a fluorine-based organic silicon compound can be added to lower the refractive index, an organic silicon compound can be added to increase the refractive index, and a boron-based organic compound can be added to further increase the refractive index. Specifically, tetraethoxysilane, tetramethoxysilane, tetrapropoxysilane, tetrabutoxysilane, alkyltrialkoxysilane, Colcoat 40 (manufactured by Colcoat), MS51 (manufactured by Mitsubishi Chemical), Snowtex (manufactured by Nissan Chemical), etc. Organosilicon compounds, ZAFLON FC-110, 220, 250 (manufactured by Toa Gosei Chemical), Sexual Coat A-402B (manufactured by Central Glass), heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, trifluoropropyltrimethoxy Examples thereof include fluorine compounds such as silane, and boron compounds such as triethyl borate, trimethyl borate, tripropyl borate, and tributyl borate. These additives may be added during the preparation of the sol, or may be added after the formation of the sol. By using these additives, a more uniform and transparent sol solution can be obtained by reacting with a silanol group during or after the hydrolysis of silicon alkoxide, and the refractive index of the gel film to be formed is within a certain range. Can be changed.
[0020]
The above SiO₂A method for forming a low refractive index layer using a sol solution is the SiO 2₂A sol solution is applied to the surface of the high refractive index hard coat layer by a coating method, and then the coated material is irradiated with an active energy ray or heat-treated, thereby forming SiO.₂A gel film can be formed, and the adhesion of the gel film to the high refractive index hard coat layer is remarkably improved. The thickness of the low refractive index layer thus formed is usually preferably in the range of about 50 to 300 nm.
SiO₂Examples of the method for applying the sol solution to the high refractive index hard coat layer include a spin coating method, a dip method, a spray method, a roll coater method, a meniscus coater method, a flexographic printing method, a screen printing method, and a bead coater method.
[0021]
The heat treatment of the coating layer performed after the application of the sol solution is performed at a temperature equal to or lower than the thermal deformation temperature of the transparent base film. For example, when the transparent substrate film is a polyethylene terephthalate film (PET), a silica gel film can be formed by heat treatment at a temperature of about 80 to 150 ° C. for about 1 minute to 1 hour. Such heat treatment conditions vary depending on the type and thickness of the transparent substrate film to be used, and may be determined according to the type of transparent substrate film to be used.
[0022]
Examples of active energy rays used for curing after application of the sol solution include electron beams and ultraviolet rays, and electron beams similar to those used for curing the high refractive index hard coat layer are particularly preferable.
The heat treatment and electron beam irradiation are preferably performed while substituting air with oxygen or in a sufficient oxygen atmosphere.₂Generation, polymerization and condensation are promoted, and a more homogeneous and high quality gel layer can be formed.
[0023]
In the example shown in FIG. 2, a fine unevenness 5 is provided on the outermost surface of the antireflection film to impart antiglare properties to the antireflection film. The fine uneven shape may be formed by any conventionally known method. For example, when a high refractive index hard coat layer is formed by a transfer method, a fine uneven shape is formed on the surface as a base material film of a transfer material. A high refractive index hard coat layer coating solution is applied and cured on the film, and then the high refractive index hard coat layer is passed through the transparent base via an adhesive or the like, if necessary. Examples thereof include a method of transferring to the surface of the material film and imparting a fine uneven shape to the surface of the high refractive index hard coat layer.
[0024]
As another method, a coating liquid for a high refractive index hard coat layer is applied and dried on the surface of the transparent substrate film, and the mat film as described above is pressure-bonded to the surface of the resin layer in that state. There is a method in which the resin layer is cured, then the mat film is peeled off, and the fine uneven shape of the mat film is transferred to the surface of the high refractive index hard coat layer. In any case, since the low refractive index layer formed on the surface of the high refractive index hard coat layer having such a fine uneven shape is a thin film, the above fine uneven shape 5 appears on the surface of the low refractive index layer. .
[0025]
The antireflection film of the present invention can be further provided with layers for imparting various functions in addition to the above-described layers. For example, an adhesive layer or a primer layer is provided to improve the adhesion between the transparent substrate film and the high refractive index hard coat layer, or a plurality of high refractive index hard coat layers are provided to improve the hard performance. It can be. As described above, the refractive index of the other layer provided between the transparent base film and the high refractive index hard coat layer is an intermediate value between the refractive index of the transparent base film and the refractive index of the high refractive index hard coat layer. It is preferable that
[0026]
The other layer may be formed by applying a desired coating solution directly or indirectly on a transparent substrate film as described above, or highly refracting on the transparent substrate film. When forming the refractive index hard coat layer by transfer, it is formed by applying a coating liquid for forming another layer on the high refractive index hard coat layer previously formed on the release film, and then forming a transparent substrate. Another layer may be transferred to the transparent substrate film by laminating the film and the release film with the release film coating surface facing inward and then peeling the release film. Further, an adhesive may be applied to the lower surface of the antireflection film of the present invention, and this antireflection film can be used by being attached to an object to be antireflection, for example, a polarizing element.
[0027]
The antireflection film of the present invention obtained as described above is used for various displays such as word processors, computers, televisions, plasma display panels, the surfaces of polarizing plates used in liquid crystal display devices, sunglasses lenses made of transparent plastics, and prescription glasses. It is useful for preventing reflection of surfaces such as lenses, optical lenses such as camera finder lenses, covers of various instruments, window glass of automobiles, trains and the like.
[0028]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples.
Example 1
Methyltriethoxysilane (MTEOS) is ideally SiO₂Or MeSiO_1.5MTEOS was dissolved in methyl ethyl ketone as a solvent so that the solid content concentration when assuming that it was hydrolyzed and condensed to 3% by weight, and stirred for 30 minutes until the liquid temperature was stabilized at 25 ° C. (liquid A) .
In the liquid A, hydrochloric acid having a concentration of 0.005N as a catalyst was added in an equimolar amount with the alkoxide group of MTEOS, and hydrolysis was performed at 25 ° C. for 3 hours (liquid B). To this solution B, a mixture of sodium acetate and acetic acid as a curing agent is added and stirred for 1 hour at 25 ° C.₂A sol solution was obtained.
[0029]
An ionizing radiation curable resin (X-12-2400: trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) on a smooth PET film (Lumirror T-60: trade name, manufactured by Diafoil Co., Ltd., thickness 50 μm) ZrO₂A liquid resin composition in which ultrafine particles (No. 926: trade name, manufactured by Sumitomo Osaka Cement Co., Ltd., refractive index 1.9) are mixed at a weight ratio of 2: 1 is applied by gravure reverse coating so as to be 7 μm / dry The coating film was cured by irradiating an electron beam with an acceleration voltage of 175 KeV for 5 Mrad to form a high refractive index hard coat layer. On this high refractive index hard coat layer, a two-component curable adhesive (LX660, KW75 (curing agent): trade name, manufactured by Dainippon Ink & Chemicals) was applied by gravure reverse coating to form an adhesive layer.
[0030]
Next, a PET film (A-4300: trade name, manufactured by Toyobo Co., Ltd., 100 μm thick) is laminated through this adhesive layer, and after aging at 40 ° C. for 4 days, the PET film (T-60) is peeled off. Then, the high refractive index hard coat layer was transferred onto a PET film (A-4300).
On the high refractive index hard coat layer on the obtained PET film (A-4300), the above-mentioned SiO is further added.₂The sol solution was applied so that the film thickness was 0.1 μm / dry, and heat treatment was performed at 120 ° C. for 1 hour to obtain the antireflection film of the present invention.
The obtained antireflection film had a total light transmittance of 94.0%, a haze value of 0.5, and a minimum reflectance of 0.8 in the visible light wavelength region, and was excellent in antireflection properties. Further, the surface pencil hardness was 3H, and the hardware property was excellent.
[0031]
Example 2
Ionizing radiation curable resin (X-12-2400) and ZrO on a mat PET film (Lumirror E-06, trade name, manufactured by Toray Industries, Inc., thickness 50 μm) having fine irregularities formed on the surface₂A liquid resin composition containing ultrafine particles (No. 926) in a weight ratio of 2: 1 was applied by gravure reverse coating so as to be 7 μm / dry, and an electron beam was irradiated at an acceleration voltage of 175 KeV for 5 Mrad to form a coating film. It was cured to form a high refractive index hard coat layer having antiglare properties. A two-component curable adhesive (LX660 (main agent), KW75 (curing agent)) was applied on the high refractive index hard coat layer by gravure reverse coating to form an adhesive layer.
[0032]
Next, a PET film (A-4300) was laminated through this adhesive layer, and after aging at 40 ° C. for 4 days, the PET film (Lumirror E-06) was peeled off to form a high refractive index hard coat layer. Transferred onto a PET film (A-4300). The surface of the high refractive index hard coat layer on the PET film (A-4300) has the same fine uneven shape as the surface shape of the PET film (Lumirror E-06).
On the high refractive index hard coat layer on the obtained PET film (A-4300), the SiO 2 of Example 1 was used.₂The sol solution was applied so that the film thickness was 0.1 μm / dry, and heat treatment was performed at 120 ° C. for 1 hour to obtain the antireflection film of the present invention.
The obtained antireflection film had a total light transmittance of 93.5% and a haze value of 0.7, and was excellent in antireflection properties. Further, the surface pencil hardness was 3H, and the hardware property was excellent.
[0033]
Example 3
A 100 μm thick PET film (A-4300) was prepared as a transparent substrate film. On the other hand, ZrO having a refractive index of 1.9₂A liquid resin composition in which ultrafine particles (No. 926) and ionizing radiation curable resin (X-12-2400) were blended at a weight ratio of 2: 1 was formed on the PET film (A-4300) at a film thickness of 5 μm / It was applied by gravure reverse coating so as to be dry, and the solvent was removed by drying.
[0034]
A mat PET film (Lumirror E-06) having fine irregularities formed on the surface is laminated on the PET film (A-4300) having the dry resin layer via the resin layer, and then an electron beam The film was irradiated with 4 Mrad at an acceleration voltage of 150 KeV to cure the coating, and the mat PET film (Lumirror E-06) was peeled off to form fine irregularities on the surface of the resin layer. Next, the SiO of Example 1 was formed on the fine uneven surface.₂The sol solution was applied so that the film thickness was 0.1 μm / dry, and heat treatment was performed at 120 ° C. for 1 hour to obtain the antireflection film of the present invention.
The obtained antireflection film had a total light transmittance of 93.5% and a haze value of 9, and was excellent in antireflection properties and antiglare properties. Moreover, the surface pencil hardness was 3H and it was excellent also in hard property.
[0035]
Comparative Example 1
An antireflection film was produced in the same manner as in Example 1 except that a SiOx film was formed as a low refractive index layer by vacuum deposition. This antireflection film had a total light transmittance of 93.7% and a haze value of 1.0, and the antireflection properties were inferior to those of the above examples. The surface pencil hardness was 2H.
[0036]
Comparative Example 2
An antireflection film was produced in the same manner as in Example 2 except that a SiOx film was formed as a low refractive index layer by vacuum deposition. This antireflection film had a total light transmittance of 92.5% and a haze value of 1.2, and the antireflection properties were inferior to those of the above examples. The surface pencil hardness was 2H.
[0037]
Comparative Example 3
An antireflection film was produced in the same manner as in Example 3 except that a SiOx film was formed as a low refractive index layer by vacuum deposition. This antireflective film had a total light transmittance of 92.0% and a haze value of 12, and the antireflective property was inferior to that of the above example. Further, the surface pencil hardness was 2H, which was inferior to that in the above example.
[0038]
【The invention's effect】
As described above, according to the present invention, lower silicon alkoxide is hydrolyzed, fine particles of several nanometers are prepared by a sol-gel method, and a sol solution in which the ultrafine particles are dispersed is obtained from a transparent substrate film. After applying to the high refractive index hard coat layer of the surface, heat treatment is performed at a temperature lower than the heat deformation temperature of the transparent base film, or irradiation with active energy rays is performed to form SiO₂By forming the gel layer, a low refractive index layer having substantially the same performance as that of the low refractive index layer obtained by the vapor phase method can be obtained, and a base material having a low thermal deformation temperature such as a plastic base material Even if is used, it is possible to form a high-performance and high-quality antireflection film.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a cross section of an example of an antireflection film of the present invention.
FIG. 2 is a diagram illustrating a cross section of another example of the antireflection film of the present invention.
[Explanation of symbols]
1: Transparent base film
2: High refractive index hard coat layer
3: Low refractive index layer
4: Adhesive layer
5: Fine uneven shape

Claims (7)

In the antireflection film obtained by laminating a high refractive index hard coat layer and a low refractive index layer directly or via another layer on a transparent substrate film, the low refractive index layer is R _m Si (OR ′) _n. (R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m + n is 4, and m and n are each an integer) and prepared by hydrolyzing a silicon alkoxide in the presence of acetic acid. An antireflective film comprising a SiO ₂ gel layer formed from a SiO ₂ sol solution having a SiO ₂ concentration of 0.1 to 10% by mass to which sodium acetate or lithium acetate is added.   2. The antireflection film according to claim 1, wherein the low refractive index layer has a refractive index of 1.38 to 1.46.   The antireflection film according to claim 1, wherein the antireflection film has a fine uneven shape on the outermost surface and is provided with antiglare properties as a whole film.   The antireflection film according to claim 1, wherein the high refractive index hard coat layer has a refractive index of 1.50 to 2.30. In the method for producing an antireflection film comprising laminating a high refractive index hard coat layer and a low refractive index layer directly or via another layer on a transparent substrate film, the low refractive index layer is made of R _m Si ( OR ′) _n (R and R ′ represent an alkyl group having 1 to 10 carbon atoms, m + n is 4, and m and n are integers), and hydrolyzes a silicon alkoxide in the presence of acetic acid. The SiO ₂ sol solution having a SiO ₂ concentration of 0.1 to 10% by mass to which sodium acetate or lithium acetate has been added is applied directly or via another layer to the surface of the transparent substrate film, method for producing an antireflection film, characterized in that the formed coating layer thermal treatment or irradiation of ionizing radiation to form a Si0 ₂ gel layer.   The method for producing an antireflection film according to claim 5, wherein the refractive index of the low refractive index layer is 1.38 to 1.46.   The method for producing an antireflection film according to claim 5, wherein a fine irregular shape is formed on the outermost surface, and the antiglare property is imparted to the entire film.

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