JP2000338303A - Antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film which is excellent not only in reflection preventive effect but also in adhesive strength of an antireflection layer to a substrate and durability thereof. SOLUTION: This antireflection film is formed by successively laminating a hard coating layer, a primer layer and the antireflection layer in this order on the transparent substrate, where the primer layer is a silica film having organic groups which are formed by plasma CVD method by using an organic silicon compound as starting material. The organic silicon compound is at least one kind selected from monoalkyl-hexaalkyl disiloxane, where the number of carbon in the alkyl group is 1-3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflection film having excellent anti-reflection properties and excellent adhesion and durability of an anti-reflection layer to a substrate.

[0002]

2. Description of the Related Art Conventionally, transparent substrates such as glass and plastic are used for displays such as curve mirrors, rearview mirrors, goggles, window glasses, personal computers, word processors, and various other commercial displays. And
When observing the visual information of objects, characters, figures, etc. through these transparent substrates, or the image from the mirror through the transparent substrate and the image from the reflective layer, the surface of these transparent substrates reflects light, and There is a problem that it is difficult to read important visual information.

Conventionally, there has been a technique for preventing the reflection of light.
Applies anti-reflective paint to glass and plastic surfaces
0.1μm thick on the surface of a transparent substrate such as glass
About MgF_TwoA method of providing an ultra-thin or metal-deposited film such as
Ionizing radiation curable resin on the surface of plastic lenses, etc.
Is applied, and further deposited thereon by evaporation. _xAnd MgF_TwoMembrane
Forming a cured film of ionizing radiation curable resin
Further, there has been a method of forming a coating film having a low refractive index.

[0004]

In the above, an antireflection film obtained by laminating a transparent inorganic thin film on a transparent substrate to provide an antireflection function has excellent antireflection properties, but the base material is particularly transparent plastic. In the case of a sheet (in which a hard coat layer may be formed), there is a problem in the adhesion of the antireflection layer to the base material, and the flexibility between the base material and the antireflection layer is different. The anti-reflection layer cannot follow the flexibility of the base material, and the anti-reflection layer suffers from fine cracks, the anti-reflection layer is partially peeled off, and the uniformity of the anti-reflection property is impaired. There was a gender problem.

As a method for solving such a problem, it has been proposed to use a silica film formed by a sol-gel method on a substrate surface as an underlayer. A thickness of several μm was required. When such a thick underlayer is formed, the function of the antireflection layer formed thereon may be impaired because the refractive index of the underlayer differs from that of the substrate. Accordingly, an object of the present invention is to provide an anti-reflection film having excellent anti-reflection properties and also having excellent adhesion and durability of an anti-reflection layer to a substrate.

[0006]

The above object is achieved by the present invention described below. That is, the present invention is an antireflection film in which a hard coat layer, a primer layer, and an antireflection layer are laminated in this order on a transparent base sheet, wherein the primer layer is formed by plasma CVD using an organosilicon compound as a raw material. Provided is an antireflection film, which is a silica film having an organic group formed by a method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings showing preferred embodiments. As shown in FIG. 1, the antireflection film of the present invention is an antireflection film obtained by laminating a hard coat layer, a primer layer and an antireflection layer on a transparent substrate sheet in this order, There is a feature in the configuration.

A preferred embodiment of the present invention is as follows. (1) The silica film is SiO _x (R) _y (where R is an alkyl group having 1 to 3 carbon atoms, x is 1.50 to 1.99, y
Is 0.02 to 1.00). (2) The antireflection film as described above, wherein the organosilicon compound is at least one of monoalkyl to hexaalkyldisiloxane (the alkyl group has 1 to 3 carbon atoms). (3) The absolute value of the difference between the value of the refractive index of the primer layer and the value of the refractive index of the hard coat layer is 0 <absolute value of the difference ≦
The above antireflection film, which is 0.01. (4) The above antireflection film, wherein the thickness of the primer layer is 10 to 100 nm.

Next, the constituent materials of the antireflection film of the present invention and the production method will be described. The transparent substrate sheet used in the present invention is formed from a stretched or unstretched film of ceramic such as glass or a transparent plastic. In addition to ordinary optical glass, as a transparent plastic, for example, polyester, polyamide, polyimide,
A thermoplastic resin sheet or film of polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polymethyl methacrylate, polycarbonate, polyurethane or the like can be used. The transparent substrate sheet may be provided with a primer layer or an adhesive layer in order to strengthen the adhesion with the hard coat layer formed thereon. These base sheets have a thickness of generally 50 to 300 μm, although they vary depending on the use and the material.

The hard coat layer provided on the base sheet is usually formed of a thermosetting resin and / or an ionizing radiation type resin. A hard coat layer is formed by applying and curing an uncured coating solution containing these resins on a transparent substrate sheet using a conventionally known coating method. The coating liquid has a thickness of the hard coat layer of preferably 0.5
To 6 μm, more preferably 3 to 6 μm. If the thickness is too small, it is difficult to maintain the hardness of the antireflection layer formed on the transparent substrate sheet, and
By setting it to the range of m, it is possible to maintain good hardness, and it is possible to impart hard performance to the antireflection film. Making the hard coat layer unnecessarily thick not only impairs the flexibility of the antireflection film, but also increases the curing time during its formation, lowers productivity, and increases manufacturing costs. It is not preferable.

In the present invention, the hard coat layer, the adhesive layer or the primer layer can be provided with fine irregularities for the purpose of imparting an antireflection property to the obtained antireflection film in addition to the excellent antireflection property. . The hard coat layer (irregular shape) is in direct contact with the antireflection layer,
The refractive index of the hard coat layer is formed smaller than the refractive index of the antireflection layer. In the present invention, "hard performance"
Alternatively, “hard coat” means that a pencil hardness test according to JIS K 5400 shows a hardness of H or more.

Preferable thermosetting resins and / or ionizing radiation type resins for forming a hard coat layer satisfying the above requirements (these are sometimes collectively referred to as reaction curable resins in the present invention). For example, those having an acrylate functional group, for example, relatively low molecular weight polyester, polyether, acrylic resin, epoxy resin, polyurethane, alkyd resin, spiro acetal resin, polybutadiene, polythiol polyene resin,
Oligomers or prepolymers such as (meth) acrylates of polyfunctional compounds such as polyhydric alcohols (hereinafter, acrylate and methacrylate are referred to as (meth) acrylates) and ethyl as a reactive diluent ( Monofunctional monomers such as (meth) acrylate, ethylhexyl (meth) acrylate, styrene, vinyltoluene, and N-vinylpyrrolidone; and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, Propylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acryl Over bets, it is used that relatively large amounts include neopentyl glycol di (meth) acrylate.

Further, when the above-mentioned ionizing radiation-curable resin is used as an ultraviolet-curable resin, a photopolymerization initiator such as acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime is used. It is preferable to use a mixture of an ester, a thioxanthone, or n-butylamine, triethylamine, tri-n-butylphosphine, or the like as a photosensitizer.

The above-mentioned ionizing radiation-curable resin includes a reactive organosilicon compound represented by the general formula R _m Si (OR ′) _n (wherein R and R ′ are alkyl groups having 1 to 10 carbon atoms). And m + n = 4, and m and n are each an integer.). Examples of the silicon compound include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-ter
t-butoxysilane, tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltrimethoxysilane, Methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyldimethoxysilane, methyldiethoxysilane, Xyltrimethoxysilane and the like. The refractive index of the hard coat layer thus formed is usually 1.50 to 1.6.
5

In the present invention, the surface of the hard coat layer formed as described above does not affect the anti-reflection property of the anti-reflection layer and has excellent durability such as excellent adhesion and bending resistance to the anti-reflection layer. Forming a primer layer that imparts properties. In the present invention, the primer layer is formed as a silica film having an organic group by a plasma CVD method using an organic silicon compound as a raw material. Although the plasma CVD method used here is well known, a silica film having an organic group can be formed by appropriately setting the conditions.

The silica film formed as described above is made of SiO
_x (R) _y (where R is an alkyl group having 1 to 3 carbon atoms, x is 1.50 to 1.99, and y is 0.02 to 1.00)
Having an organic group, has good adhesion to the hard coat layer and the antireflection layer, and exhibits an excellent primer effect with a very thin film. In the above formula, when x is less than 1.5 and y exceeds 1.00,
The silica film is unsatisfactory in that it is colored yellowish brown and loses transparency, and the required strength cannot be obtained.
When the value of y exceeds 99 and the value of y is less than 0.02, the flexibility of the silica film is lost, and the adhesiveness is insufficient, and the results are insufficient.

The organosilicon compound used to form the primer layer as described above includes monoalkyl to hexaalkyldisiloxane (the alkyl group has 1 to 1 carbon atoms).
3) is preferable, and specific examples thereof include hexamethyldisiloxane, tetramethyldisiloxane, octamethylcyclotetrasiloxane, tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, methylsilane, tetramethylsilane, and ethylsilane. Among them, the properties of the obtained silica film, cost,
Hexamethyldisiloxane and tetramethyldisiloxane are preferably used for reasons such as material handling.

The primer layer has an absolute value of a difference between a refractive index value of the primer layer and a refractive index value of the hard coat layer so as not to adversely affect the antireflection effect of the antireflection layer. It is preferable that 0 <absolute value of difference ≦ 0.01. If the absolute value exceeds 0.01, reflection at the interface with the adjacent layer cannot be ignored, and disadvantages such as deterioration of the antireflection function occur. Further, the thickness of the primer layer is preferably from 10 to 100 nm.

The above-mentioned primer layer is formed by plasma CVD.
An example of preferable conditions when forming by the method is that the flow rate of the raw material gas is 0.17 SLM for the organosilicon compound and 0.5 for the oxygen.
1 SLM, helium 0.51 SLM, argon 0.35
SLM, plasma generation power 2.1 kW, 40 kW
z is applied between the film forming drum and the gas ejection electrode.
The feed speed of the substrate sheet is 3 to 30 m / min.

In the present invention, an antireflection layer is formed on the surface of the primer layer. The configuration of the antireflection layer is not particularly limited, but since the primer effect of the primer layer is particularly effective for an inorganic thin film, it is preferable to form the antireflection layer from an inorganic thin film.

A preferred structure of the antireflection layer will be described with reference to FIG. FIG. 2 is a diagram for explaining the configuration of the antireflection layer. In the illustrated example, the high refractive index layer 1 is provided on the surface of the primer layer.
Although this is an example in which four low-refractive-index layers 2, high-refractive-index layers 3, and low-refractive-index layers 4 are alternately laminated, the present invention is not limited to this four-layer configuration, and two, three, five, or A stacked structure of more than that may be used.

As a material constituting the high refractive index layer,
For example, ZnO having a refractive index of 1.5 or more (refractive index of 1.9)
0, the following values indicate the refractive index), TiO_Two(2.3 ~
2.7), CeO_Two(L.95), Sb_TwoO_Five, (1.7
1), SnO _Two(1.997), ITO (1.95),
In _TwoO _Three(2.00), Y_TwoO_Three(1.87), La_TwoO_Three
(1.95), Al_TwoO_Three(1.63), HfO _Two(2.
00), ZrO_Two(2.05) and the like. these
Among them, metal oxides having a refractive index of 1.78 to 2.4 are particularly preferable.
Are preferred, especially ITO, TiO_Two, SnO_Two, In_Two
O_Three, ZrO_TwoAnd mixed oxides thereof.
New

The high refractive index layer can be formed by a known method such as a sputtering method or a plasma CVD method. In the case of a four-layer structure as shown in FIG.
Is set to 50 to 150 nm, and the substrate-side high refractive index layer 1 is set to 10 to 150 nm.
Preferably, it is formed to a thickness of 50 nm. The low refractive index layer has a refractive index of 1.42 to 1.51, and can be formed from silica by a known method such as a sputtering method or a plasma CVD method. In the case of a four-layer structure as shown in the drawing, it is preferable that the air-side low refractive index layer 4 has a thickness of 70 to 120 nm and the substrate side low refractive index layer 2 has a thickness of 10 to 50 nm. The total thickness of the antireflection layer is usually 3
The range is from 0 to 300 nm.

One example of a preferred method for producing the antireflection film of the present invention is as follows. First, an uncured hard coat layer made of a curing reaction type resin is formed on a transparent substrate sheet, and after laminating and shaping a mat-shaped shaping film having fine irregularities thereon as necessary, The hard coat layer is cured by heat treatment and / or ionizing radiation treatment. Next, the above-mentioned imprinting film is peeled off and removed from the hardened hard coat layer to form fine irregularities on the surface of the hard coat layer. Next, a primer layer is formed on the hard coat layer as described above, and then the high refractive index layer 1, the low refractive index layer 2, the high refractive index layer 3, and the low refractive index layer are formed on the surface thereof as shown in FIG. The four antireflection films of the present invention are obtained by alternately laminating four layers. The structure of the antireflection layer is 1
This is an example, and the present invention is not limited to the illustrated example. Also, the formation of the fine unevenness is not essential.

The anti-reflection film of the present invention obtained as described above is an anti-reflection film having excellent anti-reflection properties and excellent adhesion and durability of the anti-reflection layer to the hard coat layer. A polarizing plate laminated with a polarizing element can display a clear image without reflected light on a liquid crystal display device incorporating the polarizing plate. Also, a clear image without reflection can be displayed on a cathode ray tube having the antireflection film of the present invention bonded to the surface.

[0026]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Example 1 A-4350 (a biaxially stretched polyethylene terephthalate film having a thickness of 188 µm: manufactured by Toyobo Co., Ltd.), which is a transparent base sheet, was coated with a hard coat resin (PET-D31).
Concentration of 37% by weight with toluene
Diluted and applied and dried, cured by ionizing radiation,
A hard coat layer having a thickness of 7.5 μm was formed. The refractive index of this hard coat layer was 1.523. A primer layer made of silica was formed on this hard coat layer using a plasma CVD apparatus under the following conditions. When the film thickness of the formed primer layer was measured by XRF, it was found to be 23 nm.
Met. The refractive index of the primer layer was 1.531.

Conditions for the plasma CVD method Source gas: hexamethyldisiloxane, oxygen, helium and argon Source gas flow rate: hexamethyldisiloxane = 0.17 S
LM, oxygen = 0.51SLM, helium = 0.51SL
M and argon = 0.35 SLM Plasma generation: A power of 2.1 kW, 40 kHz was applied between the film forming drum and the gas ejection electrode. Feeding speed of substrate sheet: 9 m / min.

Then, an ITO layer 25 nm, a SiO ₂ layer 25 nm,
An ITO layer of 85 nm and a SiO ₂ film of 92 nm were laminated in this order to obtain an antireflection film of the present invention. The refractive index of the SiO ₂ layer in the antireflection layer was 1.452, and the refractive index of the ITO layer was 2.002. When the silica film as the primer layer was analyzed by Fourier transform IR, the peak derived from Si—CH ₃ was 1260 cm.
It was detected near ^-1 . In addition, Si- in the silica film
Si obtained from the area of absorption at 1080 cm ^-1 derived from O-Si and the area of absorption attributable to Si-CH ₃ described above.
The ratio of -CH ₃ / Si-O was 1/19.

Comparative Example 1 An antireflection film of Comparative Example was obtained in the same manner as in Example 1 except that the primer layer was not provided on the hard coat layer.

Evaluation 1. Adhesiveness The antireflection films obtained in Examples and Comparative Examples were subjected to a cellophane tape peeling test of the antireflection layer.
The cellophane tape peeling test was performed five times with 10 × 10 cross-cuts using cellophane tape manufactured by Nichiban Co., Ltd. Example 1 was 100/100 and Comparative Example was 0/100.

[0031]

According to the present invention, it is possible to provide an anti-reflection film which is excellent in anti-reflection property and excellent in adhesion and durability of the anti-reflection layer to the hard coat layer of the substrate sheet.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic layer configuration of an antireflection film of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of an antireflection layer.

Claims (5)

[Claims] 1. A hard coat layer on a transparent substrate sheet,
An antireflection film obtained by laminating a primer layer and an antireflection layer in this order, wherein the primer layer is a silica film having an organic group formed by a plasma CVD method using an organosilicon compound as a raw material. Anti-reflection film. 2. The method according to claim 1, wherein the silica film is SiO _x (R) _y (where R is an alkyl group having 1 to 3 carbon atoms, and x is 1.50 to 1.9).
9. The antireflection film according to claim 1, wherein y is 0.02 to 1.00. 3. The method according to claim 1, wherein the organosilicon compound is a monoalkyl compound.
Hexaalkyldisiloxane (the alkyl group has 1 carbon atom
The antireflection film according to claim 1, wherein the antireflection film is at least one of the following. 4. The method according to claim 1, wherein an absolute value of a difference between a refractive index value of the primer layer and a refractive index value of the hard coat layer is 0 <absolute value of difference ≦ 0.01. The antireflection film according to claim 1. 5. The primer layer has a thickness of 10 to 100.
The antireflection film according to any one of claims 1 to 4, which has a thickness of nm.