JP3931408B2 - Anti-glare hard coat film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antiglare hard coat film suitable for being provided on the screen of various display devices, particularly LCDs, CRTs, PDPs, ECDs, ELDs, FEDs, or light emitting diode display devices. .
The “film” in the antiglare hard coat film of the present invention means a so-called film shape, a so-called sheet shape, and any of these cases.
[0002]
[Prior art]
In the above-mentioned various displays such as LCD and CRT, there is a drawback that light is incident on the screen from the outside, and this light is reflected on the screen surface, making it difficult to view the display image. In particular, with the rapid spread and enlargement of flat panel displays in recent years, solving the above drawbacks (hereinafter referred to as anti-glare) has become an increasingly important issue. In particular, the liquid crystal display does not emit light confidently, and unless it has a built-in backlight, it is necessary to perform image display using external light.
Conventionally, as a means for imparting antiglare properties, an antiglare layer composed of a film or a sheet having a concavo-convex structure on the surface by various methods such as sandblasting, embossing, blending of inorganic and organic fine particles has been proposed. In addition to providing a feeling of fineness to the appearance and eliminating the feeling of roughness when touched, the surface has a finer concavo-convex structure (hereinafter referred to as a finer structure) to prevent glare caused by high-definition displays. There is an increasing demand for a concavo-convex structure.
[0003]
However, if the concavo-convex structure formed on the surface of the antiglare hard coat film has a generally uniform microstructure, the scratches are conspicuous by scratching all the convex parts that come into contact during the frictional or scratching action. Deterioration of scratch resistance and surface hardness occurs. In other words, scratch resistance and surface without reducing effects such as elimination of the fine texture of the texture obtained by the formation of fine concavo-convex structure and the feeling of roughness when touched, and prevention of glare caused by high-definition display There is a need for improved hard coat properties such as hardness.
[0004]
[Problems to be solved by the invention]
The present invention was made in order to solve the problems required for the film or sheet as described above, and has a fine concavo-convex structure on the surface and exhibits a good antiglare effect, and also has excellent scratch resistance. An object is to provide an antiglare hard coat film having surface characteristics and hard coat properties, and a method for producing the same.
[0005]
[Means for Solving the Problems]
Means provided by the present invention to solve the above-mentioned problem is the invention shown in claim 1,
An active energy ray-curable resin coating layer is provided on at least one surface of a substrate made of transparent plastic, and the surface of the active energy ray-curable resin coating layer has two types of irregularities with different average height differences. The two types of unevenness are composed of a fine uneven portion having an average height difference of 0.1 to 2.0 μm and an uneven portion having an average height difference of 2.1 to 10 μm. It is an antiglare hard coat film.
[0006]
According to this, it is a hard coat film in which an active energy ray-curable resin coating layer is provided on at least one surface of a transparent plastic film or a sheet substrate, and fine irregularities are formed on the surface of the hard coat film (or sheet). For the purpose of improving the damage to the structure and the frictional action and scratching action, the concave-convex structure having a relatively large height difference than the fine concave-convex structure is provided.
In other words, the formation of a concavo-convex structure with a large difference in level gives the effect of reducing the contact area on the surface of the hard coat film during friction and scratching operations to provide scratch resistance and hard coat properties with excellent surface hardness. ing.
As a result, the surface of the hard coat film has two uneven structures with different height differences between peaks and valleys, so that the surface has a fine uneven structure and hard coat properties with excellent scratch resistance and surface hardness. It became possible to provide an antiglare hard coat film or sheet.
The active energy rays are ultraviolet rays, electron beams, radiation, visible rays, or other so-called broad electromagnetic waves, and the like, as long as they have an action of imparting activity (promoting a chemical reaction) to the material. . However, when comprehensively evaluating the performance, ease of handling, cost, practicality, etc. required for the antiglare hard coat film provided on the screen of the display device, which is an application field of the present invention, ultraviolet rays are most suitable, Next is the order of electron beams.
[0007]
Then, the The two concave convex, the mean height difference portion and the average height difference between the fine irregularities of 0.1~2.0μm consists uneven portion of 2.1～10Myuemu.
[0008]
Here, if the average height difference of the former is less than 0.1 μm, it is not preferable because light incident from the outside is not sufficiently scattered. In addition, if the height difference of the former exceeds 2.0 μm, it will not be possible to obtain sufficient effects such as demonstrating the fineness of appearance, eliminating the roughness when touched, and preventing glare. It is not preferable.
And in the latter case, if the height difference is less than 2.1 μm, the effect of reducing the contact area of the hard coat film surface during the frictional action or scratching action is reduced, and it is affected by friction and scratching. Therefore, it is not preferable. If it is less than 2.0 μm, there is no distinction between the former and the latter, the configuration of the present invention itself is not made, and the average height difference itself becomes too small as a whole, resulting in friction resistance and scratch resistance. The problem that the effect of sex disappears and it becomes easy to become wrinkled on the whole arises.
Also, if the height difference of the former exceeds 10 μm, it is not preferable because it is not suitable for use on the screen of the display device because the roughness of the appearance and the feeling of roughness when touched are excessive.
[0009]
More preferably, an invention shown in claim 2, the configuration of claim 1 a antiglare hard coat film which is based,
In particular, the number of all convex portions of the portion having the average height difference of 0.1 to 2.0 μm occupies 60 to 95% of the total number of convex portions of the fine uneven structure on the surface of the antiglare hard coat film. It is characterized by doing.
[0010]
Here, if it is less than 60%, the fine uneven structure does not provide sufficient effects such as the appearance of fine texture, the elimination of the rough feeling when touched, and the prevention of the glare. On the other hand, if it exceeds 95%, the effect of reducing the contact area on the surface of the hard coat film during the frictional action or scratching action is reduced, and the influence of friction or scratching is not preferable.
[0011]
Also, on at least one surface of a substrate made of transparent plastic , fine particles having approximately two types of particle diameters and active energy ray-curable resin, which are at least one of these components, are applied and then applied to the application surface. Curing the active energy ray-curable resin coating layer by irradiating with active energy rays, or
The active energy ray curable resin was applied to at least one surface of a substrate made of transparent plastic, and the active energy ray curable resin coating layer was cured by irradiating the active energy ray curable resin coating layer with active energy rays. Later, at least one of sandblasting or embossing,
By either of the above, an active energy ray-curable resin coating layer provided on the surface with a concavo-convex structure composed of two types of fine concavo-convex having different concavo-convex average height differences can be provided on the substrate .
[0012]
Inorganic or organic fine particles can be suitably used as the fine particles having approximately two types of particle sizes. A known coating technique can be suitably used when a coating layer of an active energy ray-curable resin (optionally dispersed with the fine particles described above) is applied to form a coating layer.
A known technique can also be applied to the sandblasting method. In this case, for example, at least two types of processing fine particles having different particle diameters are prepared and used in different steps. At that time, the processing time and the strength to be sprayed are different to form fine irregularities having two kinds of average height differences.
Moreover, a well-known technique can be applied also about the embossing method.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. First, the constituent material of the antiglare hard coat film (or sheet) will be described in order, followed by the production method of the antiglare hard coat film (or sheet).
[0014]
<Constituent material of antiglare hard coat film>
FIG. 1 shows an outline of an antiglare hard coat film according to the present invention.
The material of the transparent plastic film or sheet as the substrate 1 is not particularly limited, and can be appropriately selected from known transparent plastic films or sheets having appropriate mechanical rigidity.
Specific examples include polyester, polyethylene, polypropylene, cellophane, triacetyl cellulose, diacetyl cellulose, acetyl cellulose butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, polystyrene, polycarbonate, polymethylpentene, polysulfone. , Polyether ketone, acrylic, nylon, fluororesin, polyimide, polyetherimide, polyether sulfone, etc., but in the present invention, at present, particularly triacetyl cellulose film and uniaxial stretching In addition to being excellent in transparency, polyester is preferable in that it has no optical anisotropy.
[0015]
The active energy ray-curable resin for forming the hard coat layer 2 is not particularly limited, and the active energy ray can be arbitrarily used as long as it is a resin that gives a coating film having a pencil hardness of H or higher by ultraviolet ray or electron beam curing. it can.
Examples of such UV curable resins are synthesized from polyfunctional acrylate resins such as acrylic acid or methacrylic acid ester of polyhydric alcohol, diisocyanate, polyhydric alcohol, and hydroxyester of acrylic acid or methacrylic acid. Examples of such polyfunctional urethane acrylate resins.
In addition to these, polyether resins having an acrylate functional group, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, and the like can be suitably used as necessary. .
[0016]
In addition, as reaction diluents for these resins, 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, hexanediol (meta) having a relatively low viscosity are used. ) Bifunctional or higher monomers and oligomers such as acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentyl glycol di (meth) acrylate, and monofunctional monomers For example, acrylic acid esters such as N-vinylpyrrolidone, ethyl acrylate and propyl acrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate Derivatives such as acrylate, hexyl methacrylate, isooctyl methacrylate, 2-hydroxyethyl methacrylate, cyclohexyl methacrylate, and nonylphenyl methacrylate, tetrahydrofurfuryl methacrylate, and its caprolactone modified products, styrene, α-methylstyrene, acrylic Acids and the like and mixtures thereof can be used.
[0017]
In the present invention, when the active energy ray is ultraviolet light, it is necessary to add a photosensitizer (radical polymerization initiator), such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl methyl. Benzoins such as ketals and alkyl ethers thereof; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone; anthraquinones such as methylanthraquinone, 2-ethylanthraquinone, 2-aminoanthraquinone Thioxanthones such as thioxanthone, 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; ketones such as acetophenone dimethyl ketal and benzyl dimethyl ketal Lumpur like; benzophenone, and the like 4,4-bis benzophenones such as methylamino benzophenone and azo compounds.
These can be used alone or as a mixture of two or more thereof, and further, tertiary amines such as triethanolamine and metadiethanolamine; benzoic acid derivatives such as 2-dimethylaminoethylbenzoic acid and ethyl 4-dimethylaminobenzoate, etc. It can be used in combination with a photoinitiator aid or the like.
The usage-amount of an organic peroxide or a photoinitiator is 0.5-20 weight part with respect to 100 weight part of polymerization components of the said resin composition, Preferably it is 1-15 weight part.
[0018]
The fine concavo-convex structure 3 and the concavo-convex structure 4 on the hard coat film surface can be formed by various methods such as sand blasting, embossing, or adjusting the blending of inorganic or organic fine particles. As the inorganic or organic fine particles, any fine particles that retain good transparency in the active energy ray-curable resin can be used arbitrarily.
[0019]
In general, fine particles made of silica, alumina, titania, zirconia, etc. are used as the inorganic fine particles. Among them, silica particles, particularly synthetic silica particles are preferable in terms of antiglare properties, resolution, hard coat properties and the like. . Both regular and amorphous silica can be used. Conductive transparent fine particles such as tin oxide, indium oxide, cadmium oxide, and antimony oxide can also be used regardless of imparting charging properties.
[0020]
Further, as the organic fine particles, hard fine particles having an appropriate cross-linking structure inside the particles and not swelled by an active energy ray-curable resin, a monomer, a solvent, or the like can be used. For example, particle internal cross-linked styrene resin, styrene-acrylic copolymer resin, acrylic resin, divinylbenzene resin, silicone resin, urethane resin, melamine resin, styrene-isoprene resin, benzoguanamine resin, other reactivity A microgel or the like can be used. The blending amount of the transparent fine particles is 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight per part by weight of the active energy ray-curable resin.
[0021]
Moreover, a well-known general coating additive can be mix | blended as needed. For example, silicone and fluorine additives that impart leveling, surface slip properties, etc. are effective in preventing scratches on the surface of the cured film, and in the case of using ultraviolet rays as active energy rays, the additives described above Bleeding to the air interface can reduce the inhibition of curing of the resin by oxygen, and an effective degree of curing can be obtained even under low irradiation intensity conditions. These addition amounts are suitably 0.01 to 0.5 parts with respect to 100 parts by weight of the active energy ray-curable resin.
[0022]
<Method for producing antiglare hard coat film>
The method for applying the hard coat layer is arbitrary, but in the production stage, a roll coater, a reverse roll coater, a gravure coater, a knife coater, a bar coater or the like is generally used.
[0023]
When ultraviolet rays are used as the active energy ray source, 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.
A metal halide lamp is generally used when a filler is included or a thick film is cured.
[0024]
Also, when curing using electron beam, it is emitted from various electron beam accelerators such as cockloftwald type, bandecraft type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, high frequency type, etc. An electron beam having an energy of 50 to 1000 keV, preferably 100 to 300 keV can be used.
[0025]
The antiglare hard coat film of the present invention has a structure composed of two layers, the transparent plastic substrate and the hard coat layer. Two or more kinds of inorganic or organic fine particles having different particle sizes are blended in the hard coat layer resin by a known dispersion method such as a disper mixer, a sand mill, etc., and the film thickness after curing is preferably 0.5 μm or more. Is applied so as to be 10 μm or less, and then cured by irradiation with active energy rays.
[0026]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
Unless otherwise specified, “part” and “%” are based on weight.
[0027]
<Hard coat layer>
The electron beam curable coating composition shown in the following formulation was prepared according to the procedure described below. First, a silica dispersion is obtained by changing the mixing weight ratio of silica particles having an average particle size of 2.0 μm and a particle size of 5.0 μm to a mixed solvent of toluene / 2-butanone = 1/1 and performing high-speed stirring with a disper mixer. Adjusted.
Next, the silica dispersion was gradually added to the mixed solution of the hexafunctional urethane acrylate oligomer and trimethylolpropane triacrylate while stirring.
[0028]
Hexafunctional urethane acrylate oligomer 40 parts
(Product name: U-6HA, manufactured by Shin-Nakamura Chemical Co., Ltd.)
60 parts of trimethylolpropane triacrylate
(Toa Gosei Co., Ltd.)
Toluene 50 parts 2-butanone 50 parts Silica 5 parts
(Product name: Mizupell, S-200, particle size 2.0 μm, and
Product name: Mizuperl, S-500, particle size 5.0 μm.
All are made by Mizusawa Chemical)
[0029]
Next, after applying the electron beam curable coating composition on one side of a triacetylcellulose film having a thickness of 80 μm with a wire bar and evaporating the solvent, a coating layer having a thickness of about 2.5 μm is formed. A hard coat layer was produced by curing an electron beam with an acceleration voltage of 200 keV from the coating film side under the condition of an absorbed dose of 3 Mrad.
[0030]
<Evaluation method>
About the obtained anti-glare hard coat film, the average height difference of the concavo-convex shape on the surface of the hard coat film formed by silica of each particle diameter is observed by SEM, and the ratio of the number of convex portions on the surface is determined by the three-dimensional surface roughness. After measurement by measurement, various physical properties were evaluated by the following measurement methods.
・ Surface roughness: Surface roughness and contour of Surfcom 550AD (Tokyo Seimitsu Co., Ltd.)
It was measured by a shape measurement system.
・ Pencil hardness: Use a pencil with a different hardness to determine the presence or absence of scratches under a 500 g load.
It was.
-Scratch resistance: 4 hard coat film surfaces with # 0000 steel wool
Friction 10 times while applying a load of 00g.
The degree of was observed visually.
[0031]
<Result of evaluation>
Of the concavo-convex shape on the surface of the hard coat layer, the average height difference of the fine concavo-convex structure due to the silica having a particle diameter of 2.0 μm was 0.7 μm, and the height difference of the concavo-convex structure due to the particle diameter of 5.0 μm was 3.4 μm.
(Table 1) shows the results of evaluating various physical properties by the ratio of the number of convex portions formed of silica of each particle size and the measurement method described above.
[0032]
[Table 1]
<Image of Table 1>
[0033]
From this, it is compared with the case where only silica particles having an average particle diameter of 2.0 μm are blended by setting the weight mixing ratio of each silica having an average particle diameter of 2.0 μm and an average particle diameter of 5.0 μm to 8: 2. Thus, it can be seen that although the surface roughness (Ra value) hardly changes, the scratch resistance is improved and the pencil hardness is also improved.
[0034]
【The invention's effect】
As is clear from the description of the above-described Examples, a hard coat film in which an active energy ray-curable resin coating layer is provided on at least one surface of the transparent plastic substrate according to the present invention, and the hard coat film or sheet is provided. An anti-glare hard coat film having both a fine concavo-convex structure on the surface and a hard coat property having scratch resistance and excellent surface hardness by containing a concavo-convex structure having two different peaks and valleys in the inside or A sheet could be provided. In particular, when used on the display surface, the fine concavo-convex structure not only gives the appearance a fine texture and eliminates the feeling of roughness when touched, but also prevents glare associated with higher display resolution. In addition, the inclusion of a concavo-convex structure with a large difference in height provides a hard coat property with excellent scratch resistance and excellent surface hardness due to the friction effect and the effect of reducing the contact area with the hard coat layer surface during use. Is also possible.
[0035]
In general, according to the present invention, an anti-glare hard coat film having a fine concavo-convex structure on the surface and exhibiting a good anti-glare effect, having excellent surface properties with scratch resistance, and also having hard coat properties, The manufacturing method could be provided.
[Brief description of the drawings]
FIG. 1 shows a cross-sectional view of the layer structure of an antiglare hard coat film or sheet of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Hard-coat layer 3 ... Fine uneven structure 4 ... Uneven structure

Claims (2)

An active energy ray-curable resin coating layer is provided on at least one side of a substrate made of transparent plastic,
On the side of the surface of the active energy ray curable resin coating layer comprises a concavo-convex structure having an average height difference of the irregularities is made from two different kinds of irregularities, the two types of irregularities average height difference 0.1~2.0μm An anti-glare hard coat film comprising a fine uneven portion and an uneven portion having an average height difference of 2.1 to 10 μm . The total number of the convex portions of the concavo-convex portion of the average height difference 0.1~2.0μm is, occupies 60% to 95% of the total number of the convex portions of the fine uneven structure of the antiglare hard coat film surface The anti-glare hard coat film according to claim 1 .

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