JP5261856B2 - Anti-glare film and method for producing the same - Google Patents

Description

Technical field to which the invention belongs

  The present invention relates to a method for producing an antiglare film suitable for use in a surface of a high-definition image display such as a CRT or liquid crystal panel used for image display of a word processor, computer, television or the like. More specifically, the present invention relates to a method for producing an antiglare film having excellent surface hardness and antiglare properties and good visibility when used in various displays.

  When viewing the display on such a display, the light emitted from the inside is too dazzling if it goes straight without diffusing in the display, and the light is incident on the display and is reflected off the screen. This makes it difficult to view the displayed image. In order to solve these problems, various anti-glare measures have been taken for various displays so far.

The anti-glare treatment method for anti-glare hard coat film is
(1) A method of roughening the surface by a physical method during and after curing to form a hard coat layer,
(2) A method of mixing a filler in a hard coat agent for forming a hard coat layer,
And can be broadly divided.
Of these two methods, the latter method (2) is the mainstream, and silica particles are mainly used as the filler. However, the saponification treatment necessary for laminating the antiglare hard coat film and the polarizing plate causes the filler to be deposited on the film surface, causing a change in appearance due to the falling off of the filler. .

Problems to be solved by the invention

  An object of the present invention is to provide an antiglare film having excellent scratch resistance and antiglare properties and a method for producing an antiglare film with an antireflection function in order to solve the above problems. It is.

Means for solving the problem

[Means for Solving the Problems]
The invention according to claim 1 is an antiglare film in which an antiglare layer and an antireflection layer are provided on the antiglare layer on at least one surface of the transparent substrate film. The antiglare layer made of a translucent resin containing a light diffusing agent is cured using ultraviolet light or electron beam in an atmosphere having an oxygen concentration of 0.3% or more and 15% or less, saponified, and then reflected. It is a manufacturing method of the anti-glare film characterized by forming a prevention layer .

Also, an invention according to claim 2, wherein the anti-reflection layer, characterized by being formed using a mixture of silane coupling agent and fluorinated silane coupling agent hydrolyzed sol solution by catalytic It is a manufacturing method of the anti-glare film of Claim 1 .
The invention according to claim 3 is the antiglare film according to claim 1 or 2 , wherein the atmosphere having the oxygen concentration of 0.3% or more and 15% or less is performed by nitrogen purge. It is a manufacturing method.

The invention according to claim 4, translucent resin used in the antiglare layer, characterized in that it is a UV and electron beam curing type resin, proof of any one of claims 1 to 3 It is a manufacturing method of a dazzling film.

The invention according to claim 5 is the antiglare film according to claim 4 , wherein the translucent diffusing agent used for the antiglare layer is composed of an organic or / and inorganic filler. It is a manufacturing method.

The invention according to claim 6 is an antiglare film produced by the method for producing an antiglare film according to any one of claims 1 to 5 , wherein the transmission haze value of the antiglare film is as follows. Is an antiglare film characterized by being in the range of 1% to 30%.

The base plastic film used in the antiglare film of the present invention is not particularly limited, and may be appropriately selected from plastic films used as base materials for conventional optical hard coat films. it can.
For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. polyester film, polyethylene film, polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film , Polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film , Nylon film, acrylic resin film It can be mentioned.

The thickness of these plastic films is not particularly limited and is appropriately selected depending on the situation, but is usually in the range of 25 to 500 μm, preferably 50 to 250 μm.
In addition, a surface treatment can be performed for the purpose of improving the adhesion to the antiglare layer provided on the substrate. As this surface treatment method, for example, surface roughening treatment such as sandblasting or solvent treatment, or surface oxidation treatment such as corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, etc. Can be mentioned.

  The antiglare film of the present invention has a hard coat antiglare layer on the plastic film, and the antiglare layer is colloidal in a cured product of ultraviolet ray and electron beam curable resin. Fine particles are homogeneously dispersed.

There is no restriction | limiting in particular as an ultraviolet-ray and electron beam curable resin used for the said glare-proof layer, It can select and use suitably from what is used conventionally.
This ultraviolet curable resin contains a photopolymerizable prepolymer, a photopolymerizable monomer, a photopolymerization initiator, and the like.
The electron beam curable resin contains a photopolymerizable prepolymer and a photopolymerizable monomer.

Examples of the photopolymerizable prepolymer include polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate. These photopolymerizable prepolymers may be used alone or in combination of two or more.
Examples of the photopolymerizable monomer include polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol di (meth) acrylate. Particularly in the present invention, it is preferable to use urethane acrylate as a prepolymer and dipentaerythritol hexa (meth) acrylate as a monomer.

Furthermore, examples of the photopolymerization initiator include acetophenones, benzophenones, α-amyloxime esters, tetramethylchuram monosulfide, thioxanthones, and the like.
Further, n-butylamine, triethylamine, poly-n-butylphosphine and the like can be mixed and used as a photosensitizer.

  In the hard coat antiglare film of the present invention, the translucent diffusing agent used in the antiglare layer is an inorganic filler such as silica particles or an organic filler such as acrylic resin, and the filler is an aggregate of colloidal particles. And the average grain festival has the preferable range of 0.3-10 micrometers from the surface of the balance of anti-glare property and visibility.

In the antiglare layer of the hard coat antiglare film of the present invention, the content of aggregates due to colloidal particles is a cured product of ultraviolet and electron beam curable resin from the viewpoint of balance between antiglare property and light transmittance. It is preferably in the range of 1 to 30 parts by weight per 100 parts by weight.
The thickness of the antiglare layer is preferably in the range of 0.5 to 20 μm from the viewpoint of the balance between scratch resistance and economy. The hardness of the antiglare layer is preferably H or higher in pencil hardness, and can have the scratch resistance necessary for the hard coat film.

In preparing the hard coat agent for forming the antiglare layer, there is no particular limitation on the order of blending the components, and UV and electron beam curable resins, colloidal particles, photopolymerization initiators, etc. are added and mixed in various solvents. To do.
As the solvent, toluene is preferable, and there is an advantage that transparency is maintained because a polyethylene terephthalate film or a polyacetylcellulose film, which is a kind of transparent base film, is not dissolved.
Moreover, well-known additives, such as an antifoamer and a leveling agent, can be mix | blended with this hard-coat agent if desired. There is no restriction | limiting in particular about solid content concentration of a hard-coat agent, The range of 10 to 70 weight% is preferable from surfaces, such as coating property, drying property, economical efficiency, and the range of 30 to 50 weight% is especially suitable.

Next, the hard coat agent thus prepared is applied onto the plastic film so that the cured film thickness is 0.5 to 20 μm, preferably 1 to 10 μm, and is dried.
The coating method is not particularly limited, and a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, or the like can be used.
The thickness of the coating layer can be controlled by calculating the required amount of the hard coating agent from the solid content concentration of the hard coating agent and the density of the antiglare layer after curing.

  In the present invention, the coating layer after drying is cured by irradiation with ultraviolet rays and electron beams in an atmosphere purged with nitrogen to form a hard coat layer with less oxygen damage and high surface hardness.

There is no restriction | limiting in particular about the ultraviolet irradiation apparatus used for hardening, For example, the well-known ultraviolet irradiation apparatus using a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fusion lamp etc. can be used.
The amount of ultraviolet irradiation is usually about 100 to 800 mJ / cm2. There is no restriction | limiting in particular about an electron beam irradiation apparatus, and an acceleration voltage is 80-300 kV normally.

  The antiglare film thus obtained is preferably subjected to a saponification treatment in order to increase adhesion and prevent static electricity when laminating the polarizing plate. By this treatment, the surface of the triacetyl cellulose film, which is one of the transparent substrate films, becomes hydrophilic, and the adhesion to the polarizing film made of polyvinyl alcohol is improved.

  The saponification treatment is performed as follows. The antiglare hard coat film is immersed in an alkali solution (1.5 N NaOH) at 50 ° C. for 2 minutes and washed with distilled water. Further, after neutralizing by immersing in 0.5% by weight of sulfuric acid for 30 seconds, washing with distilled water is repeated twice, followed by natural drying.

The antiglare film thus obtained is excellent in scratch resistance, saponification resistance and antiglare properties, and has good visibility when used in various displays.
Therefore, for example, it can be used as a hard coat antiglare film for polarizing plates in a liquid crystal display or as a protective film for various displays.

The antireflection layer provided on the antiglare layer of the present invention is composed of a low refractive index layer and a high refractive index layer.
Here, the low refractive index layer is made of, for example, an ultraviolet ray and an electron beam curable resin in which MgF2 (refractive index: 1.38), SiO2 (refractive index: 1.46), which are fine particles having a low refractive index, are dispersed. Or various sols comprising oligomers obtained by hydrolyzing a mixture of a silane coupling agent and a fluorine-based silane coupling agent with a catalyst. However, the present invention is not limited to this.

  As a method for forming the low refractive index layer, the above-described various coating methods are applied so that the cured film thickness becomes 0.01 to 1 μm, and after drying, ultraviolet rays and electrons are used as necessary. Radiation is performed.

  Other formation methods of the low refractive index layer may be appropriate means such as a vacuum deposition method, a sputtering method, a reactive sputtering method, an ion plating method, and an electroplating method. You may form by the coating film of a coating material, ultra-thin films, such as MgF2 with a film thickness of about 0.1 micrometer, a metal vapor deposition film, or the vapor deposition film of SiOx or MgF2.

  Further, the high refractive index layer in the antireflection layer of the present invention is TiO2 (refractive index; 2.3 to 2.7), Y2O3 (refractive index; 1.87), La2O3 (refractive index) which are fine particles having a high refractive index. 1.95), ZrO2 (refractive index; 2.1), Al2O3 (refractive index; 1.62), or the like, which is made of ultraviolet or electron beam curable resin, is limited to this. is not.

  As a method for forming a high refractive index layer, it is applied by the above-mentioned various coating methods so that the cured film thickness is 0.01 to 1 μm, dried, and then irradiated with ultraviolet rays and electron beams as necessary. I do.

  Another method for forming the high refractive index layer may be an appropriate means such as a vacuum deposition method, a sputtering method, a reactive sputtering method, an ion plating method, an electroplating method, etc. The film may be formed of an ultrathin film such as TiO 2 having a thickness of about 0.1 μm or a metal vapor deposition film.

The antiglare film according to the present invention is less susceptible to erosion by a saponification solution because of less oxygen inhibition when cured in a low oxygen concentration region and progress of surface curing.
Moreover, since the surface hardness is high, excellent scratch resistance can be obtained.
On the contrary, when curing in a high oxygen concentration region, the surface is easily eroded by the saponification solution, resulting in a large uneven surface, and excellent adhesion between the two layers when the antireflection layer is laminated on the antiglare layer. Sex is obtained.
Therefore, there is an appropriate oxygen concentration range. When obtaining excellent saponification resistance and scratch resistance, the oxygen concentration is 2% or less, and when obtaining adhesion with the upper layer, the oxygen concentration is 0.3% or more. is necessary.

  The transmission haze value of the antiglare film in the present invention is 1% to 30%. When the haze value is less than 1, the antiglare property is poor. On the other hand, when the haze value is greater than 30, the image contrast is poor, the visibility is poor, and the function of the display is deteriorated. The method for measuring the haze value will be described later.

Next, the present invention will be described in detail with reference to examples. The present invention is not limited in any way by these examples. The performance of the hard coat antiglare film was evaluated according to the following method.
(1) Saponification resistance The hard coat film after saponification was observed with a scanning electron microscope [manufactured by Hitachi, Ltd., model S-4000], and the state of the filler on the surface was visually evaluated.
(2) Scratch resistance Using # 0000 steel wool, 10 reciprocating surfaces were rubbed with a load of 250 g, and the presence or absence of scratches and the appearance change of the scratched and unscratched parts were visually evaluated.
(3) Haze value The antiglare hard coat film with an antireflection function was measured using a image measuring instrument [NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.].
(4) Pencil hardness Based on JIS K5400, it evaluated by the testing machine method.
(5) Visual evaluation glaring: The light of a fluorescent lamp was incident on the surface of the film, and the reflection of the outline of the fluorescent lamp was evaluated.
Visibility: A film is placed on newspaper and evaluated by character recognition.

Example 1
200 parts by weight of filler dispersion concentrate (Daiichi Seika Kogyo Co., Ltd., Seika Beam EXF37M-FC) is added to 100 parts by weight of the clear resin liquid of UV curable resin (Daiichi Seika Kogyo Co., Ltd., Seika Beam EXF37T). In addition, a hard coating agent was prepared by diluting with toluene as a solvent so that the solid content concentration was 50%.
Next, the hard coat agent was applied on a triacetyl cellulose film (FZ Photo Film Co., Ltd., UZ) having a thickness of about 80 μm so that the cured film thickness was 5 μm, and dried at 70 ° C. for 1 minute. Processed.
Next, nitrogen purging is performed as appropriate, and ultraviolet rays are applied to the dried coating film using an ultraviolet irradiation device (Fusion lamp manufactured by Fusion UV Systems Japan Co., Ltd.) in an atmosphere of oxygen concentration of 1 to 2%. Irradiated with a light amount of about 200 mJ / cm 2 and cured to prepare a hard coat film. Further, the film was saponified.
The performance evaluation results of this film are shown in Table 1.

(Comparative Example 1)
In Example 1, an appropriate nitrogen purge was performed to cure the coating film by irradiation with ultraviolet rays in an atmosphere having an oxygen concentration of 3 to 20.8% to prepare a hard coat film, which was saponified.
The performance evaluation results of this film are shown in Table 1.

(Example 2)
A hard coat film was prepared and saponified in the same manner as in Example 1 except that a resin obtained by adding 400 parts by weight of the filler dispersion concentrate to 100 parts by weight of the clear resin liquid was used.
The performance evaluation results of this film are shown in Table 2.

(Comparative Example 2)
In Example 2, by appropriately performing nitrogen purge, a hard coat film was prepared by irradiating the coating film with ultraviolet rays in an atmosphere having an oxygen concentration of 3 to 20.8%, and saponified.
The performance evaluation results of this film are shown in Table 2.

As is clear from Tables 1 and 2, the results of Example 1 and Example 2 showed the same results except for the haze value. The surface state of the antiglare layer is caused by the cured state of the resin regardless of the amount of filler.
As the oxygen concentration is lowered, the oxygen barrier is reduced, the surface curability is improved, and the resin is less dissolved by the saponification treatment, so that the filler is not deposited and the resin is buried in the resin at an oxygen concentration of 2% or less. Become. By performing a nitrogen purge at the time of UV curing, filler deposition can be prevented even after saponification.

(Example 3)
A hard coat film was prepared in the same manner except that the dry coating film prepared in Example 1 was appropriately purged with nitrogen and irradiated with ultraviolet rays in an atmosphere having an oxygen concentration of 0.3 to 15%. did. Next, tetraethoxysilane (manufactured by Kanto Chemical Co., Inc.) and fluorine silane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM7803) were mixed at a molar ratio of 95: 5, and a 0.22 times weight solvent (2 -Diluted with methoxyethanol: isopropyl alcohol = 1: 1). To this solution, 7.5-fold mol of 1N hydrochloric acid (in terms of water weight) was added to the silane, and the mixture was hydrolyzed by stirring for 1 hour to obtain a sol solution. And what added said solvent here and made solid content concentration 4% was used as the coating liquid of the anti-reflective layer. On the hard coat film after saponification, the coating solution for the antireflection layer is applied so that the cured film thickness becomes 0.1 μm, and heat treatment is performed at 120 ° C. for 5 minutes. A coated film was prepared.
The performance evaluation results of this film are shown in Table 3.

(Comparative Example 3)
In Example 3, a nitrogen purge was performed, and the coating film was cured by irradiation with ultraviolet rays in an atmosphere having an oxygen concentration of 0.1% to prepare a hard coat film. Thereafter, saponification treatment was performed, and a hard coat film with an antireflection function was prepared in the same manner as in Example 3.
The performance evaluation results of this film are shown in Table 3.

Example 4
The dry coating film prepared in Example 2 was appropriately purged with nitrogen, and a hard coat film was prepared in the same manner except that it was irradiated with ultraviolet rays in an atmosphere having an oxygen concentration of 0.3 to 15%. did. Then, a 0.1 μm antireflection layer was provided in the same manner as in Example 3 to prepare the hard coat film with an antireflection function.
The performance evaluation results of this film are shown in Table 4.

(Comparative Example 4)
In Example 4, after purging with nitrogen and curing the coating film by irradiating with ultraviolet rays in an atmosphere having an oxygen concentration of 0.1%, a hard coat film was prepared and then saponified, and antireflection was conducted in the same manner as in Example 4. A hard coat film with function was created.
The performance evaluation results of this film are shown in Table 4.

As is clear from Tables 3 and 4, the results of Example 3 and Comparative Example 3 and the results of Example 4 and Comparative Example 4 showed substantially the same results except for the haze value. All of them tend to be easily scratched with respect to scratch resistance as the oxygen concentration decreases. In other words, the higher the oxygen concentration, the larger the unevenness of the antiglare layer due to the precipitation of filler, the better the adhesion to the antireflection layer and the better the scratch resistance.
However, when the nitrogen purge is performed and the oxygen concentration is 0.3% or more, the appearance change due to the falling off of the filler does not occur, the adhesion between the antiglare layer and the antireflection layer is high, and the scratch resistance is excellent.

(Example 5)
In the dry coating film prepared in Example 1, the hard coating agent is applied by changing the mixing ratio of the clear resin liquid and the filler dispersion concentrated liquid, the nitrogen purge is performed, and curing is performed in an atmosphere having an oxygen concentration of 2%. Thus, a hard coat film having a transmission haze value of 1 to 30% was prepared.
Table 5 shows the performance evaluation results of this film.

(Comparative Example 5)
In the same manner as in Example 5, a hard coat film having a transmission haze value of 0.1 to 0.9% was prepared.
Table 5 shows the performance evaluation results of this film.

(Comparative Example 6)
In the same manner as in Example 5, a hard coat film having a transmission haze value of 40% was prepared.
Table 5 shows the performance evaluation results of this film.

  As can be seen from Table 5, when the haze value is less than 1, the glare of the film is large and the antiglare property is poor. On the other hand, when the haze value is larger than 30, the image contrast is poor and the visibility is poor. The transmission haze value of the antiglare hard coat film in the present invention is preferably 1% to 30%.

Effect of the invention

  The present invention is a hard coat film having excellent saponification resistance, scratch resistance and antiglare property even when the antiglare layer alone is cured in a nitrogen purge atmosphere with an oxygen concentration of 2% or less, and Even in an antiglare film with an antireflection function in which an antireflection layer is laminated on the upper layer, when it is cured in an atmosphere having an oxygen concentration of 0.3% or more, the scratch resistance is excellent in adhesion between the antiglare layer and the antireflection layer. It has the outstanding effect that the anti-glare film which has property can be manufactured.

Sectional drawing which shows the anti-glare film concerning one Embodiment of this invention.

DESCRIPTION OF SYMBOLS 1 ... Transparent base film 2 ... Translucent resin 3 ... Translucent diffusing agent 4 ... Anti-glare layer 5 ... Antireflection layer 6 ... Anti-glare hard coat film

Claims (6)

In an antiglare film in which an antiglare layer and an antireflection layer are provided on the antiglare layer on at least one surface of the transparent base film, the base film contains a light transmissive diffusing agent. The anti-glare layer made of resin is cured using ultraviolet rays or an electron beam in an atmosphere having an oxygen concentration of 0.3% or more and 15% or less, and saponified to form an anti-reflection layer. A method for producing an antiglare film.
The antireflection layer, the method for producing an antiglare film according to claim 1 wherein the mixture of the silane coupling agent and fluorinated silane coupling agent characterized by being formed by using a hydrolyzed sol solution by catalytic .
The method for producing an antiglare film according to claim 1 or 2 , wherein the atmosphere having an oxygen concentration of 0.3% or more and 15% or less is performed by nitrogen purge.
The method for producing an antiglare film according to any one of claims 1 to 3 , wherein the translucent resin used for the antiglare layer is an ultraviolet ray and an electron beam curable resin.
The method for producing an antiglare film according to claim 4 , wherein the translucent diffusing agent used for the antiglare layer comprises an organic or / and inorganic filler.
An antiglare film manufactured by the method for manufacturing an antiglare film according to any one of claims 1 to 5 , wherein a transmission haze value of the antiglare film is in a range of 1% to 30%. An antiglare film characterized by that.

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