JPH10239502A - Antireflection material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an antireflection material, particularly an antireflection film, excellent in antireflection effect, scratch resistance and transparency, at a low cost, by forming a plurality of resin layers on base material, and specifying the refractive indexes of the adjacent resin layers out of the resin layers. SOLUTION: Two or more resin layers are formed on the base material formed of an organic polymer film with high transparency such as cellulose triacetate, and the refractive indexes of two adjacent layers out of these resin layers are made different by 0.01 or more. It is desirable that resin containing fine grain of silica or the like is used for one layer out of the resin layers. When the resin layers formed on the base material are resin layers A-D in order from the base material side, for instance, the resin layer B is made lower in the refractive index than the resin layer A, the resin layer C is made higher in the refractive index than the resin layer B, and the resin layer D is made lower in the refractive index than the resin layer C so that the refractive indexes of the adjacent resin layers are different by 0.01 or more. Reflection can thereby be suppressed efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflective material, and more particularly to an anti-reflective material such as an anti-reflective film or the like suitable for a surface substrate such as a flat panel display or a touch panel of a pen input type. .

[0002]

2. Description of the Related Art Reflection of external light on a CRT or a flat panel display screen in recent years and reflected light generated at an interface with an air layer have become extremely problematic, making the screen difficult to see. For this reason, on the surface of the substrate, to prevent reflection of external light,
(1) a method of forming a single-layer or multilayer inorganic vapor-deposited layer to prevent reflection, or (2) containing fine particles such as silica,
A method of applying a mat coating and the like are known.
The method (1) is sufficient in antireflection performance, but the manufacturing process is complicated, the cost is very high, and the scratch resistance is inferior. If a hard coat layer is formed on a base material and then an inorganic vapor deposition layer is formed, the scratch resistance is improved, but is not sufficient. In the method (2), if a hard coat resin is used as a binder, a film having scratch resistance can be formed. However, in order to impart sufficient antireflection performance, a large amount of fine particles must be added. . Therefore, as the antireflection performance gradually increases, the transmittance decreases.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an anti-reflection material having excellent anti-reflection effect, scratch resistance and transparency, especially an anti-reflection film at low cost.

[0004]

According to the present invention, which solves the problems of the prior art, at least two or more resin layers are formed on a substrate, and at least two adjacent resin layers among the resin layers are formed. The resin layer is characterized in that the refractive index differs by 0.01 or more. In particular, when a resin layer containing fine particles in one layer is used, an antireflection material having both antiglare properties and antireflection properties can be obtained, and a hard coat resin layer is used as the resin layer. As a result, an antireflection material having excellent scratch resistance can be obtained.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate used in the present invention is not particularly limited, and may be any one having excellent transparency such as glass or organic polymer film. From the viewpoint of processability and application, it is preferable to use an organic polymer film having high transparency, for example, cellulose triacetate, a cellulose resin such as acetate, polyethylene terephthalate, a polyester resin such as polyethylene naphthalate, or the like. It is preferable to use an organic polymer film such as an acrylic resin such as polymethyl methacrylate or a polycarbonate resin.

The resin layer in the present invention is not particularly limited as long as it is made of a resin having excellent transparency.
If the resin layers formed on the base material are, for example, a resin layer (A), a resin layer (B), a resin layer (C), and a resin layer (D) in order from the base material side, the resin layer (B) is ), The resin layer (C) has a higher refractive index than the resin layer (B), and the resin layer (D) has a lower refractive index than the resin layer (C). I can do it. The effects of the present invention are remarkable when there is a difference of 0.01 or more in the expression of the high and low refractive indexes. Further, at least one of the resin layers may be formed of a resin containing fine particles such as silica.

[0007] These resin layers formed on the substrate (film) are preferably hard coat resin layers having a pencil hardness of H or more when cured on a glass substrate, from the viewpoint of application. As a hard coat resin for forming such a hard coat resin layer, a thermosetting resin or an ionizing radiation type resin is mainly used. Among them, ionizing radiation type resins are preferred in view of work environment and productivity.
The ionizing radiation-curable resin is formed from a paint containing a resin that is cured at least by irradiation with an electron beam or ultraviolet rays. Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, and a photopolymerization initiator, and further contains, if necessary, additives such as a sensitizer, a non-reactive resin, and a leveling agent, and a solvent. It is. The structure and molecular weight of the photopolymerizable prepolymer relate to the curing of the ionizing radiation-type curable paint, and determine properties such as hardness, refractive index, and crack resistance. The photopolymerizable polymer generally undergoes radical polymerization when an acryloyl group introduced into the skeleton is irradiated with ionizing radiation. Those cured by radical polymerization are particularly preferred because they have a high curing rate and a high degree of freedom in resin design.

[0008] As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, which has a three-dimensional network structure having two or more acryloyl groups in one molecule. As the acrylic prepolymer, urethane acrylate, melamine acrylate, polyester acrylate, and the like can be used. The photopolymerizable monomer dilutes a high-viscosity photopolymerizable prepolymer, reduces the viscosity, and improves workability.
It is used as a cross-linking agent to impart coating strength. Further, the coating film becomes harder than necessary when the mixing amount of the photopolymerizable monomer increases, so that the mixing ratio is preferably selected so as to obtain a desired hardness or a desired flexibility. For example, when used for bending the antireflection film of the present invention, the hardness is adjusted by mixing a non-reactive resin such as a thermosetting resin, a thermoplastic acrylic resin, or an epoxy resin, which is excellent in flexibility. You can do it. There are several methods for adjusting the refractive index of the hard coat layer formed from such a hard coat resin. When adjusting to a high refractive index, (1) a general photopolymerizable polymer,
Use a photopolymerizable monomer having a relatively high refractive index structurally, such as having a cyclic structure in the molecule (2)
Copolymerization of high refractive compounds such as sulfur compounds, photopolymerizable prepolymers by addition polymerization, etc., and introduction into photopolymerizable monomers,
Alternatively, there is a method of (3) using a high refractive material such as a sulfur compound as a non-reactive resin.

In order to adjust the refractive index to a low value, (4) use a structurally relatively low-refractive index from general photopolymerizable polymers and photopolymerizable monomers. (5) Fluorine compound (6) Fluorine compounds which are obtained by introducing a low-refractive material such as a silicon compound or a boron compound into a photopolymerizable prepolymer or a photopolymerizable monomer by copolymerization or addition polymerization, or acrylated. Or a silicon compound, a low refractive material such as a boron compound, as a non-reactive resin,
And so on. Further, as described above, if the difference between the refractive indices of the two adjacent resin layers is less than 0.010,
In many cases, the reflectance is reduced by only about 0.5% or less, and substantially no antireflection effect can be expected. By these methods, the hard coat resin is designed in consideration of the hardness, the refractive index, and the like.

The thickness of the formed resin layer is not particularly limited. However, considering the scratch resistance, one of the resin layers preferably has a thickness of 1 μm to 30 μm, more preferably 2 μm to 5 μm. Is set. The other resin layers are preferably set to have a film thickness such that the minimum value of the reflectance is λ = 380 nm to 780 nm. As a method for forming the resin layer when using an ionizing radiation type resin, an ionizing radiation type paint can be applied by a usual application method, for example, coating with a bar, blade, spin, spray or the like.
When an ionizing radiation-curable paint is cured by irradiation with an electron beam or ultraviolet rays, the presence of oxygen and the thickness of the coating film are closely related to the curing. Radicals generated by irradiation with ionizing radiation supplement oxygen, thereby suppressing curing. Therefore, when the thickness of the coating film is small, the surface area occupying the volume of the coating film becomes large, and the coating is easily affected by curing in air. In order to prevent such curing inhibition, irradiation is preferably performed under an inert gas such as N2 gas.

In order to laminate ionizing radiation-curable resin layers in multiple layers, the point of adhesion between the layers is important. Therefore, in the present invention, the ionizing radiation resin is applied with a Mayer bar, the curing by irradiation with ionizing radiation is stopped in a semi-cured state, the next layer is applied, and this layer is similarly stopped in a semi-cured state, and this is repeated. Finally, a method of completely curing by irradiation with ionizing radiation was adopted. When cured by this method, the resin can be strongly adhered between the layers. In the present invention, the anti-reflection effect has a reflectance of 3% or less, preferably 2.5% or less, and the transmittance is approximately 85% or more, preferably 88% or more. An antireflection material having such an antireflection effect and transmittance can be obtained economically and with good productivity by the present invention.

[0012]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Hereinafter, parts are parts by weight.) ** Example 1 70 parts of bisphenol A type acrylate, 30 parts of sulfur-containing acrylate, 3 parts of benzophenone-based photoinitiator, 3 parts of amine-based sensitization on a 188 μm-thick polyester film. 106 parts of the ionizing radiation-curable resin coating material (A) having a refractive index of 1.560 after curing was added to a solvent 200 parts
Is applied with a Meyer bar, and the solvent is dried and removed, and then irradiated with ionizing radiation for 0.2 to 0.5 seconds, semi-cured and tacked, and the first layer having a thickness of 4 μm is formed. Form. Then, 100 parts of a silicon-based acrylate, 3 parts of a benzophenone-based photoinitiator, and 3 parts of an amine-based sensitizer, and 106 parts of an ionizing radiation-curable resin paint (B) having a refractive index of 1.470 after curing are added to a solvent. The resin containing 3000 parts was applied using a Meyer bar, and after drying and removing the solvent, ionizing radiation was applied for 1 to 2 seconds to completely cure the resin.
A second layer of μm was formed.

** Example 2 On a 188 μm-thick polyester film, 106 parts of an ionizing radiation-curable resin paint (A) to which 200 parts of a solvent had been added was applied using a Meyer bar. The film is irradiated with ionizing radiation for 0.2 to 0.5 seconds, semi-cured and tacked to form a first layer having a thickness of 4 μm. After that, 106 parts of the ionizing radiation-curable resin paint (B) to which 3000 parts of a solvent had been added was applied using a Mayer bar,
After the solvent is removed by drying, the film is irradiated with ionizing radiation for 0.2 to 0.5 seconds, semi-cured and tacked to form a second layer of 0.09 μm. After that, ionizing radiation-curable resin paint (A) 1
A solution obtained by adding 3,000 parts of a solvent to 06 parts of the mixture was applied by a Meyer bar, and after the solvent was removed by drying, ionizing radiation was applied to 0.2 to 0.2 parts.
Irradiate for 0.5 seconds, semi-cured and removed tack, 0.09μ
The third layer of m is formed. Thereafter, an ionizing radiation-curable resin coating material comprising 70 parts of a silicon-based acrylate, 30 parts of a fluorine-based silicon acrylate, 3 parts of a benzophenone-based photoinitiator, and 3 parts of an amine-based sensitizer, and having a refractive index of 1.45 after curing ( C) 106 parts of a solution obtained by adding 3000 parts of a solvent was applied by a Meyer bar, and after drying and removing the solvent, ionizing radiation was applied for 1 to 2 seconds to completely cure the mixture, thereby obtaining 0.09%
A fourth layer of μm was formed.

** Example 3 On a polyester film having a thickness of 188 μm, 106 parts of an ionizing radiation-curable resin coating material (A) was coated with an average particle size of 4.5 μm.
106.5 parts of an ionizing radiation-curable resin coating (D) obtained by adding 0.5 part of silica having a m of 200 m and 200 parts of a solvent are applied by a Meyer bar, and after removing the solvent by drying, ionizing radiation is applied. Irradiate for 0.2 to 0.5 seconds, semi-curing and take tack to form a first layer having a thickness of 4 μm. Then, a solvent 3000 was added to 106 parts of the ionizing radiation-curable resin paint (B).
The resulting mixture was applied with a Meyer bar, the solvent was removed by drying, and then ionizing radiation was applied for 1 to 2 seconds to completely cure the resin, thereby forming a second layer having a thickness of 0.09 μm.

** Comparative Example 1 On a polyester film having a thickness of 188 μm, a coating obtained by adding 200 parts of a solvent to 106 parts of an ionizing radiation-curable resin coating (A) was applied by a Mayer bar, and the solvent was dried and removed. Irradiated with ionizing radiation for 1 to 2 seconds and completely cured to form a 4 μm thick hard coat layer.

** Comparative Example 2 On a polyester film having a thickness of 188 μm, a coating obtained by adding 200 parts of a solvent to 106 parts of an ionizing radiation-curable resin paint (A) was applied using a Mayer bar, and the solvent was dried and removed. Irradiate with ionizing radiation for 0.2 to 0.5 seconds, semi-harden and remove the tack to form a first layer having a thickness of 4 μm. Thereafter, a coating obtained by adding 3000 parts of a solvent to 106 parts of the ionizing radiation-curable resin paint (A) is applied using a Meyer bar, and after drying and removing the solvent, irradiation with ionizing radiation is performed for 1 to 2 seconds to completely cure the resin. Then, a second layer of 0.09 μm is formed.

** Comparative Example 3 On a polyester film having a thickness of 188 μm, a coating obtained by adding 200 parts of a solvent to 106 parts of an ionizing radiation-curable resin paint (A) was applied using a Mayer bar, and the solvent was dried and removed. Irradiate with ionizing radiation for 0.2 to 0.5 seconds, semi-harden and remove the tack to form a first layer having a thickness of 4 μm. Thereafter, 80 parts of bisphenol A type acrylate, 20 parts of sulfur-containing acrylate, and benzophenone-based photoinitiator 3
Parts of an ionizing radiation-curable resin paint (E) 10 having a refractive index of 1.551 after curing.
Six parts, to which 3000 parts of a solvent were added, was applied using a Meyer bar, and after the solvent was removed by drying, ionizing radiation was applied to 1-2 parts.
Irradiate for 2 seconds and cure completely to form a second layer of 0.09 μm.

** Comparative Example 4 On a polyester film having a thickness of 188 μm, a coating obtained by adding 200 parts of a solvent to 106.5 parts of an ionizing radiation-curable resin paint (D) was applied using a Mayer bar, and the solvent was dried. After the removal, the film is irradiated with ionizing radiation for 1 to 2 seconds to be completely cured, and a hard coat layer having a thickness of 4 μm is formed.

** Comparative Example 5 On a polyester film having a thickness of 188 μm, 106 parts of an ionizing radiation-curable resin coating material (A) was coated with an average particle size of 4.5 μm.
A solution obtained by adding 200 parts of a solvent to 112 parts of an ionizing radiation-curable resin paint (F) obtained by adding 6 parts of silica is applied by a Meyer bar, and after removing the solvent by drying, ionizing radiation is applied for 1 to 2 seconds. Irradiation and complete curing resulted in the formation of a hard coat layer having a thickness of 4 μm.

Examples 1, 2, 3 and Comparative Examples 1, 2, 3,
The hard coat films obtained in 4 and 5 were evaluated as follows, and the results are shown in Table 1. (1) transmittance 5 using a spectrophotometer UV-3100PC (Shimadzu Corporation)
The light transmittance at 50 nm was measured. The unit is%. (2) Reflectance 5 using spectrophotometer UV-3100PC (Shimadzu Corporation)
The light reflectance at 50 nm was measured. The unit is%. (3) Pencil hardness Measured according to JIS k5400. (4) Steel wool resistance The coated surface is rubbed with steel wool # 0000 to judge the degree of scratching A: No scratching B: Slightly scratched C: Scratched

[0021]

[0022]

As is clear from the above examples, the antireflection film produced according to the present invention plays a role of an antireflection function, and is excellent in transparency and scratch resistance.

Claims (4)

[Claims] 1. A method according to claim 1, wherein at least two or more resin layers are formed on the base material, and at least two adjacent resin layers of the resin layers differ in refractive index by at least 0.010 or more. Anti-reflective material. 2. The antireflection material according to claim 1, wherein at least one of the resin layers contains fine particles such as silica. 3. The anti-reflection material according to claim 1, wherein the resin layer is a hard coat resin layer formed of a thermosetting resin or an ionizing radiation-curable resin. 4. The antireflection material according to claim 1, wherein the substrate is an organic polymer film.