JP2001293818A - Reflection preventing hard coat film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection preventing hard coat film excellent in reflection preventing effect, scratch resistance, transparency, antistaining properties, weatherability or the like and capable of being manufactured at a low cost. SOLUTION: The reflection preventing hard coat film is constituted by successively forming a hard coat layer (b), a film coating layer (c) having a high refractive index and a film coating layer (d) having a low refractive index, which is mainly formed from at least one compound selected from Si(OR1)4, R24-n(OR1)n, Si(NCO)4, R1nSi(NCO)4-n and (R1O)nSi(NCO)4-n (wherein, R1 and R2 are each a 1-20C alkyl group; and n is an integer selected from 1, 2 and 3) and a Zr compound, on a plastic film (a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film which is used for applications requiring an antireflection property such as a display screen, and has characteristics such that the surface is hardly damaged by the antireflection property and is hardly stained. Hard coat film, especially having the above performance and weather resistance (high temperature and high humidity resistance)
The present invention relates to an antireflective hard coat film having excellent antireflection properties.

[0002]

2. Description of the Related Art A display screen is a typical application requiring antireflection properties. Most display screens of televisions and computers as display screens are formed with a curved surface, and the application of antireflection properties on the display screen has been performed by means such as coating or jetting. The use of a surface has become widespread, and since it is a flat surface, by forming an anti-reflective layer on the film and attaching the anti-reflective film, it is possible to provide anti-reflective properties on the display screen, and Has been proposed. Many of these antireflective films can be formed at low cost, although some films have low performance in antireflective properties, or films formed as multilayer antireflective layers by vapor deposition or sputtering. Most films have an antireflection layer as a coating layer.

[0003]

In these conventional antireflection films, a film having a multi-layered thin film layer formed by vapor deposition or sputtering is expensive and can maintain a certain level in quality. In the case of a film provided with an anti-reflection layer using a coating layer that can be formed at low cost, it is easy to maintain the quality at a relatively low level at a low cost, but the anti-reflection property is insufficient. In many cases, the performance against scratches and dirt on the surface tends to be insufficient. Accordingly, an object of the present invention is to provide an anti-reflection hard coat film which is excellent in anti-reflection effect, scratch resistance, transparency, stain resistance, etc., can be manufactured at low cost, and has excellent weather resistance (high temperature and humidity resistance). It is to provide anti-reflection properties.

[0004]

That is, the present invention provides a hard coat layer (b), a high refractive index thin film coating layer (c), and a low refractive index thin film coating layer (d) on at least one surface of a plastic film (a). In the anti-reflective hard coat film on which the low refractive index thin film coating layer (d) is sequentially formed,
_{^{i (OR 1) 4, R}} 2 4-n Si (OR 1) n, Si (NCO)
₄ , R ¹ _n Si (NCO) _4-n , (R ¹ O) _n Si (NCO)
_4-n (wherein R ¹ and R ² represent an alkyl group having 1 to 20 carbon atoms, and n represents a number selected from 1, 2, and 3) and a Zr compound. An antireflection hard coat film characterized by being mainly formed, and wherein the hard coat layer (b) is formed from an ionizing radiation-curable resin containing metal oxide fine particles. An anti-reflective hard coat film, wherein the high-refractive-index thin-film coating layer (c) is mainly formed of at least one selected from metal alkoxides and metal chelates; Furthermore, in the low refractive index thin film coating layer (d), the Zr content is 0.5 to 20 at. %. The anti-reflective hard coat film according to claim 1,

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The plastic film (a) used in the present invention is not particularly limited. However, from the viewpoint of application such as processability, a film made of a polyester resin such as polyethylene terephthalate or a film made of cellulose triacetate. It is desirable to use a polycarbonate film. Those having a thickness of 20 μm to 250 μm are preferably used. As the hard coat resin for forming the hard coat layer (b) of the present invention, a thermosetting resin or an ionizing radiation type resin is preferably applied. Above all, it is preferable to use an ionizing radiation type resin in terms of work environment and productivity, and the ionizing radiation curable resin is a resin that is cured by irradiation of at least electron beam and ultraviolet rays, and a coating containing these resins is used. Hard coat layer (b) of the present invention
Is formed. Specifically, it contains a photopolymerizable prepolymer, a photopolymerizable monomer, and a photopolymerization initiator, and further includes a sensitizer, a non-reactive resin, an additive such as a leveling agent, if necessary,
It is a paint containing a solvent.

The structure and molecular weight of the photopolymerizable prepolymer are related to the curing of the ionizing radiation curable paint, and the hardness,
It determines properties such as the refractive index and crack resistance. The photopolymerizable prepolymer is generally of a type which undergoes radical polymerization by irradiating an acryloyl group introduced into a skeleton 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. As the photopolymerizable prepolymer, an acrylic prepolymer having an acryloyl group is particularly preferable, and an acrylic prepolymer having two or more acryloyl groups in one molecule and having a three-dimensional network structure is preferable. As the acrylic prepolymer, urethane acrylate, epoxy acrylate, melamine acrylate, polyester acrylate and the like can be used. The photopolymerizable monomer is used for imparting the strength of the coating film or for lowering the viscosity of the photopolymerizable prepolymer, but the hard coat paint may be prepared mainly from the photopolymerizable monomer.

In the application of the present invention to a display screen which is one of the main applications of the antireflection hard coat film,
The required hardness of the final display screen is high, and the pencil hardness on the low refractive index thin film coating layer (d) side of the antireflective hard coat film of the present invention is 2H or more. When the hard coat coating liquid contains inorganic oxide fine particles, for example, silicon oxide, antimony oxide, tin oxide, indium oxide, zinc oxide, alumina, titania, zirconia, etc. to form a hard coat layer, a high refractive index thin film coating layer This is preferable because it has good adhesion to (c) and the hardness after forming the high-refractive-index thin-film coating layer (c) and the low-refractive-index thin-film coating layer (d) is improved. The inorganic oxide particles to be added to the hard coat coating solution preferably have a particle size of 1 to 200 nm. When the average particle size exceeds 200 nm, the transmittance tends to be impaired, and there is no problem in using two or more types of inorganic oxide particles in combination, but among these, there is a conductive property such as tin oxide. The use of particles is preferable because an antireflective hard coat film having excellent antistatic properties can be obtained.

When inorganic oxide fine particles are simply mixed and dispersed, if they are mixed in a large amount, the crosslinking density of the hard coat resin itself may decrease, and the hardness may decrease. Therefore, it is more preferable that the surface of the inorganic oxide particles is treated with an acryloxy-functional silane or the like and modified with acrylate so as to be crosslinked by ionizing radiation, and then mixed with the hard coat resin.
Since the surface acrylated inorganic oxide fine particles participate in the crosslinking with the hard coat resin, even if they are blended in a large amount, the hardness does not decrease and the hardness tends to increase. In addition, mixing is easy without the need for a step of dispersing in a hard coat resin, and excellent in permeability after mixing. Inorganic oxide fine particles subjected to acrylate surface treatment and fine particles not subjected to acrylate surface treatment may be used in combination. As a method of preparing a coating solution containing the ionizing radiation-curable resin by applying the coating solution containing the ionizing radiation-curable resin in this manner, a normal coating method, for example, coating with a bar, blade, spin, spray, gravure, or the like is performed. be able to.
The thickness of the hard coat layer (b) is not particularly limited.
The hard coat layer (b) has a refractive index of, but not limited to, about 1.5 to about 1.4 to 1.8, and preferably about 2 to 7 μm. Is done.

The high refractive index thin film coating layer (c) formed on the hard coat layer (b) is formed by coating a paint adjusted from a metal alkoxide or the like.
Those forming these high refractive index thin film layers include Zr
Zr alkoxides such as Zr tetrapropoxide and Zr tetrabutoxide represented by (OR ³ ) ₄ (R ³ represents an alkyl group having 1 to 10 carbon atoms); In (OR ⁴ ) ₃ (R
⁴ represents an alkyl group having 1 to 10 carbon atoms)
In alkoxides such as n-tripropoxide and In tributoxide; Sn alkoxides such as Sn (OR ⁵ ) ₄ (R ⁵ represents an alkyl group having 1 to 10 carbon atoms) such as Sn tetrapropoxide and Sn tetrabutoxide , In
A mixture of alkoxide and Sn alkoxide at a ratio of about 90:10, Ti (OR ⁶ ) ₄ (R ⁶
Ti alkoxides such as Ti tetrapropoxide, Ti tetrabutoxide represented by
Aluminum alkoxide and the like are preferable. The thickness of the high refractive index thin film coating layer (c) is not particularly limited.
To 0.2 μm, more preferably 0.1 to
The high refractive index thin film coating layer (c) has a refractive index of 1.5 to 2.
7, more preferably 1.8 to 2.6.

The low refractive index thin film coating layer (d) used in the present invention.
Are Si (OR ¹ ) ₄ , R ² _4-n Si (OR ¹ ) _n , Si (N
CO) ₄ , R ¹ _n (NCO) _4-n , (R ¹ O) _n Si (NC
O) _4-n (wherein R ¹ and R ² represent an alkyl group having 1 to 20 carbon atoms, and n represents a number selected from 1, 2, and 3) and Zr Those mainly formed from compounds are used. Specifically, for example,
At least one selected from tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, tetraisocyanatesilane, methylsilyltriisocyanate, dimethylsilyldiisocyanate, and Zr (OR ³ ) ₄ (R ³ represents an alkyl group having 1 to 10 carbon atoms.) Zr alkoxide such as Zr tetrapropoxide and Zr tetrabutoxide, and at least one Zr metal compound such as zirconium acetyl acetate. Things. In the low refractive index thin film coating layer (d) used in the present invention, the Zr content is Si.
0.5 to 20 at. %, More preferably 1 to 15 at. % And the Zr content is 0.5a with respect to the sum of Si and Zr.
t. %, No satisfactory improvement in weather resistance is observed, and the Zr content is 2% with respect to the sum of Si and Zr.
0 at. %, It is difficult to obtain coating stability and tends to adversely affect transparency and the like.

In the present invention, if necessary, a fluorine resin may be mixed with the silicon alkoxide or the like in order to impart antifouling properties to the antireflection hard coat film. There is no particular limitation on the fluorine-based resin,
Excellent water _{repellency, RfCH 2 CH 2 Si (OR} 2) 3-n X n
(Rf is a perfluoroalkyl group having 1 to 100 carbon atoms, R ² is an alkyl group having 1 to 10 carbon atoms, X is an alkyl group, chlorine and the like. N is a number selected from 0, 1, and 2) It is preferable to use a fluorine-based silicon alkoxide having a highly fluorinated substituent represented by the following formula: The fluorine-based silicon alkoxide is preferably fixed in the film by a metalloxane bond by the same reaction mechanism as the silicon alkoxide, so that the antifouling performance is maintained. The mixing ratio of the fluorine-based alkoxide is not particularly limited, but it is preferable that the coating layer contains 0.1 to 30% by weight of solid content. The thickness of the low-refractive-index thin film coating layer (d) is not particularly limited, but is preferably 0.05 to 0.2 μm, more preferably 0.07 to 0.12 μm, and the refractive index is not particularly limited. It is 1.5 or less, preferably 1.4 or less. The metal alkoxides and the like exemplified above are dissolved in a suitable solvent, for example, isopropyl alcohol, ethanol, methanol, water, etc., and if necessary, a suitable catalyst,
For example, an acidic compound such as hydrochloric acid, sulfuric acid, acetic acid, or nitric acid, or an alkaline compound such as ammonia is added and hydrolysis is performed to prepare a paint for a thin film coating layer. In addition, this paint
Other components such as a curing agent may be added. This coating is formed by appropriately selecting and applying coating, drying, irradiation with ionizing radiation, heat treatment, irradiation with activation energy such as excimer laser or EB irradiation, and the like. According to the present invention, an antireflection hard coat film having excellent antireflection effect, scratch resistance, transparency, antifouling property and the like, and which can be manufactured at low cost can be obtained. Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[0012]

The present invention will be described in more detail with reference to the following examples. Hereinafter, parts are by weight unless otherwise specified. The films obtained in the following examples were evaluated as follows. (1) Pencil hardness The low refractive index layer side was measured according to JIS K5400. (2) transmittance 5 using a spectrophotometer UV-3100PC (Shimadzu Corporation)
It was measured from the low refractive index layer side at a light transmittance of 50 nm. The unit is%. (3) Reflectance 5 using spectrophotometer UV-3100PC (Shimadzu Corporation)
The light reflectance at 50 nm was measured on the low refractive index layer side. The unit is%. (4) Adhesion The low refractive index layer side is scratched 11 times vertically and 11 times horizontally with a carter knife, and after adhering Cellotape (registered trademark) to the scratches, the tape is peeled in the direction of 90 degrees, and remains. Evaluate by square (5) Weather Resistance The pencil hardness and adhesion after the treatment at 1500C for 15 hours at 60 ° C and 95% RH were evaluated with a moisture resistance tester (PR-1ST manufactured by Tabai Espec).

** Example 1 A polyester film having a thickness of 188 μm was mixed with 50 parts of a hexafunctional acrylate monomer, 50 parts of tin oxide fine particles having an average particle diameter of 50 nm, 5 parts of a photopolymerization initiator, and 100 parts of methyl ethyl ketone. 5μm thickness after drying with coater
And dried with a solvent, and then irradiated with ultraviolet light at 800 mJ / cm ² using a high-pressure mercury lamp to form a hard coat layer. Next, 10 parts of titanium tetra n-butoxide, 30 parts of isopropanol (IPA) and 30 parts of n-butanol were mixed, dried with a bar coater, coated to a thickness of 0.12 μm, and dried at 140 ° C. for 1 minute. A high refractive index thin film coating layer was formed. Then, tetraethoxysilane Si
(OC ₂ H ₅ ) ₄ 24 parts, ethanol 50 parts, water 20 parts,
2 parts of zirconium tetra-n-butoxide and 4 parts of hydrochloric acid are hydrolyzed to prepare a paint, and the paint is dried to a thickness of 0.0
Apply with a bar coater to 9μm, 140 ℃
For 1 minute to form a low refractive index thin film coating layer. Thereafter, heat treatment was performed at 100 ° C. for 24 hours to prepare an antireflection hard coat film. The pencil hardness of the obtained antireflection hard coat film was 3H, the transmittance was 91%, the reflectance was 0.5%, and the adhesion was 100/100. As for the weather resistance, the pencil hardness after the treatment was 3H, and the adhesion was 100 /.
It was 100.

** Comparative Example 1 A polyester film having a thickness of 188 μm was mixed with 50 parts of a hexafunctional acrylate monomer, 50 parts of tin oxide fine particles having an average particle diameter of 50 nm, 5 parts of a photopolymerization initiator, and 100 parts of methyl ethyl ketone. 5μm thickness after drying with coater
And dried with a solvent, and then irradiated with ultraviolet light at 800 mJ / cm ² using a high-pressure mercury lamp to form a hard coat layer. Next, 10 parts of titanium tetra n-butoxide, 30 parts of isopropanol (IPA) and 30 parts of n-butanol were mixed, dried with a bar coater, coated to a thickness of 0.12 μm, and dried at 140 ° C. for 1 minute. A high refractive index thin film coating layer was formed. Then, tetraethoxysilane Si
(OC ₂ H ₅ ) ₄ 24 parts, ethanol 50 parts, water 20 parts,
A coating is prepared by hydrolyzing 0 parts of zirconium tetra-n-butoxide and 4 parts of hydrochloric acid.
Apply with a bar coater to 9μm, 140 ℃
For 1 minute to form a low refractive index thin film coating layer. Thereafter, heat treatment was performed at 100 ° C. for 24 hours to prepare an antireflection hard coat film. The pencil hardness of the obtained antireflection hard coat film was 3H, the transmittance was 92%, the reflectance was 0.5%, and the adhesion was 100/100. As for the weather resistance, the pencil hardness after the treatment was H, and the adhesion was 0/100.
Met.

[0015]

According to the present invention, a hard coat layer (b) and a high refractive index thin film coating layer (c) are formed on one surface of a plastic film (a).
Is formed, and the low-refractive-index thin-film coating layer (d) is formed on the high-refractive-index thin-film coating layer (c), whereby the antireflection effect, scratch resistance, transparency, antifouling property, etc. are excellent. Thus, an antireflection hard coat film having excellent weather resistance and being producible at low cost was obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 2/46 C08F 2/46 G02B 1/11 G02B 1/10 A 1/10 Z F term (Reference) 2K009 AA05 AA15 BB24 BB28 CC02 CC03 CC09 CC14 CC42 DD02 DD05 4F100 AA17B AA17H AH02C AH08C AK01A AK01B AK25B AK41A AK51D AK51J AK52D AK52J AK79C AK79D AK80C AK80D AL06D AR00B AR00C AR00D BA04 BA07 BA10A BA10D BA13 CC00C CC00D DE01B DE01H GB41 JA20D JB14B JK12B JK14 JL06 JL09 JM02C JM02D JN01 JN06 JN18C JN18D YY00D 4J011 PA04 PA07 PA13 PB22 PC02 PC08 QB11 QB14 QB19 QB24 UA01 UA03 VA01 WA02

Claims (4)

[Claims] 1. An anti-reflective hard coating comprising a hard coat layer (b), a high refractive index thin film coating layer (c), and a low refractive index thin film coating layer (d) sequentially formed on at least one surface of a plastic film (a). in coating film, a low refractive index thin film coating layer (d) _{^{is, Si (OR 1) 4,}} R 2 4-n Si (O
R ¹ ) _n , Si (NCO) ₄ , R ¹ _n Si (NCO) _4-n ,
(R ¹ O) _n Si (NCO) _4-n (where R ¹ , R
² represents an alkyl group having 1 to 20 carbon atoms, n is 1,
Represents a number selected from 2, 3. (1) An antireflective hard coat film characterized by being mainly formed from at least one compound selected from the group consisting of: and a Zr compound. 2. The antireflection hard coat film according to claim 1, wherein the hard coat layer (b) is formed from an ionizing radiation curable resin containing fine metal oxide particles. 3. The antireflection hard coat film according to claim 1, wherein the high refractive index thin film coating layer (c) is mainly formed from at least one selected from metal alkoxides and metal chelates. 4. Z in the low refractive index thin film coating layer (d)
r content is 0.5 to 20 a with respect to the sum of Si and Zr.
t. %. The antireflective hard coat film according to claim 1.