ANTIREFLECTION FILM (As Amended)

Abstract

The present invention relates to an antireflection film including: a hard coating layer in which center line average roughness (Ra) of the surface is 1.2 nm or less and surface energy is 34 mN/m or less; and a low refractive index layer which is formed on the hard coating layer.

Claims

1. An antireflection film comprising: a hard coating layer of which center line average roughness (Ra) of the surface is 1.2 nm or less and surface energy is 34 mN/m or less; and a low refractive index layer which is formed on the hard coating layer.

2. The antireflection film of claim 1, wherein the surface of the hard coating layer has center line average roughness (Ra) of 0.5 nm to 0.8 nm.

3. The antireflection film of claim 1, wherein the hard coating layer has surface energy of 30 mN/m to 33.5 mN/m.

4. The antireflection film of claim 1, wherein the hard coating layer comprises a binder resin containing a polymer of at least one photocurable compound selected from the group consisting of: (meth)acrylate monomers: monomers or oligomers of urethane-based (meth)acrylate monomers, epoxy-based (meth)acrylate, and ester-based (meth)acrylate; and (meth)acrylate compounds having a heterocyclic skeleton or (meth)acrylates having an alicyclic ring, each of which has at least one ethylenically unsaturated bond.

5. The antireflection film of claim 1, wherein the hard coating film comprises a binder resin containing a photocurable resin and a high molecular weight (co)polymer having a weight average molecular weight of 10,000 or higher, and organic or inorganic fine particles dispersed in the binder resin.

6. The antireflection film of claim 1, wherein the hard coating layer comprises a binder resin containing a photocurable resin, and an antistatic agent dispersed in the binder resin.

7. The antireflection film of claim 6, wherein the hard coating layer further includes at least one compound selected from the group consisting of an alkoxysilane-based oligomer and a metal alkoxide-based oligomer.

8. The antireflection film of claim 1, wherein the low refractive index layer includes a binder resin including a crosslinked (co)polymer between a photopolymerizable compound and two or more types of fluorine-containing compounds containing a photoreactive functional group, and inorganic fine particles dispersed in the binder resin.

9. The antireflection film of claim 8, wherein the two or more types of fluorine-containing compounds containing the photoreactive functional group have different fluorine content ranges depending on the types.

10. The antireflection film of claim 9, wherein the two or more types of fluorine-containing compounds containing the photoreactive functional group include a first fluorine-containing compound containing a photoreactive functional group and containing 25% to 60% by weight of fluorine.

11. The antireflection film of claim 10, wherein the two or more types of fluorine-containing compounds containing the photoreactive functional group include a second fluorine-containing compound containing a photoreactive functional group and containing 1% by weight or more and less than 25% by weight of fluorine.

12. The antireflection film of claim 11, wherein the difference in fluorine content between the first fluorine-containing compound and the second fluorine-containing compound is 5% by weight or more.

13. The antireflection film of claim 11, wherein the weight ratio between the first fluorine-containing compound and the second fluorine-containing compound is 0.01 to 0.5.

14. The antireflection film of claim 8, wherein the fluorine-containing compound containing the photoreactive functional group is an oligomer or (co)polymer having a weight average molecular weight of 2000 to 200.000, or a fluorine-containing monomer having two or more reactive functional groups in one molecule.

15. The antireflection film of claim 8, wherein the low reflective index layer contains 20 to 300 parts by weight of the two or more types of fluorine-containing compounds containing the photoreactive functional group based on 100 parts by weight of the photopolymerizable compound.

16. The antireflection film of claim 8, wherein the photoreactive functional group contained in the fluorine-containing compound is at least one selected from the group consisting of a (meth)acrylate group, an epoxide group, a vinyl group, and a thiol group.

17. (canceled)

18. The antireflection film of claim 8, wherein the binder resin contained in the low refractive index layer further includes a crosslinked (co)polymer between a photopolymerizable compound and two or more types of fluorine-containing compounds containing photoreactive functional groups, and a polysilsesquioxane in which at least one reactive functional group is substituted.

19. The antireflection film of claim 18, wherein the low reflective layer includes 0.5 to 60 parts by weight of a polysilsesquioxane in which at least one reactive functional group is substituted, based on 100 parts by weight of the photopolymerizable compound.

20-21. (canceled)

22. The antireflection film of claim 8, wherein the inorganic fine particles includes at least one selected from the group consisting of hollow silica particles having a number average particle diameter of 10 to 100 nm, and nanosilica particles having a number average particle diameter of 1 to 50 nm.

23. The antireflection film of claim 8, wherein the low refractive index layer contains 10 to 400 parts by weight of the inorganic fine particles based on 100 parts by weight of the photopolymerizable compound.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0141] Hereinafter, embodiments of the invention will be described in more detail by way of examples. However, these examples are given for illustrative purposes only, and the scope of the invention is not intended to be limited by these examples.

Preparation Example and Comparative Example: Preparation of Antireflection Film

[0142] (1) Preparation of Hard Coating Film

[0143] A salt-type antistatic hard coating solution manufactured by Toyo Ink Co. (50% by weight of solid content, product name: LJD-1000) was diluted with methyl isobutyl ketone to prepare a hard coating liquid having a solid content of 40% by weight. The diluted hard coating solution was coated onto a triacetyl cellulose film with a #10 Mayer bar, dried at 90 C. for 2 min, and then photocured under the conditions of the following Table 2 to obtain a hard coating film having a thickness of 10 m.

[0144] (1) Preparation of a Photocurable Coating Composition for Producing a Low Refractive Index Layer

[0145] Components shown in the following Table 1 were mixed and diluted with MIBK (methyl isobutyl ketone) solvent so that the solid content became 3% by weight.

TABLE-US-00001 TABLE 1 LR1 LR2 LR3 LR4 LR5 THRULYA 4320 50 50 50 42 42 X71-1203M 15 OPTOOL-AR110 15 15 18 18 RS-537 3 3 3 5 5 MA0701 4 5 MIBK-ST 10 10 10 15 13 Dipentaerythritol 18 18 15 16 13 pentaacrylate Irgacure-127 4 4 3 4 4 (Unit: % by weight based on total solid content)

[0146] 1) THRULYA 4320 (manufactured by Catalysts and Chemicals Ltd.): Hollow silica dispersion (solid content 20 wt % in MIBK solvent)

[0147] 2) X71-1203M (manufactured by Shinetsu): Fluorine-containing compound containing a photoreactive functional group (diluted to a solid content 15 wt % in MIBK solvent, fluorine content of solids: about 45 wt %)

[0148] 3) OPTOOL-AR 110 (manufactured by Daikin): a fluorine-containing compound having a photoreactive functional group (diluted to a solid content of 15 wt % in MIBK solvent, fluorine content of solids: about 51 wt %)

[0149] 4) RS537 (manufactured by DIC): Fluorine-containing compound containing a photoreactive functional group (diluted to a solid content 40 wt % in MIBK solvent, fluorine content of solids: about 17% by weight)

[0150] 5) MA0701: Polysilsesquioxane (manufactured by Hybrid Plastics)

[0151] 6) MIBK-ST (manufactured by Nissan Chemical): diluted with a nanosilica dispersion to a solid content 30% in MIBK solvent

[0152] (2) Preparation of Low Reflective Index Layer and Antireflection Film

[0153] The photocurable coating compositions obtained in Table 1 above were coated with a #3 Mayer bar on the hard coating film shown in Table 2 below and dried at 60 C. for 1 min. The dried material was subjected to ultraviolet irradiation at a dose of 100 mJ/cm.sup.2 under nitrogen purging to form a low refractive index layer having a thickness of 100 nm, thereby producing an antireflection film.

TABLE-US-00002 TABLE 2 Hard coating layer Moving speed of hard coating Whether film during purged with ultraviolet Ultraviolet Low nitrogen during irradiation intensity reflective photocuring [m/min] [mJ/cm.sup.2] index Example 1 0 47 20 LR1 Example 2 0 47 20 LR2 Example 3 0 47 20 LR3 Example 4 0 47 20 LR4 Example 5 0 47 20 LR5 Example 6 0 15 60 LR4 Comparative x 4 445 LR4 Example 1 Comparative x 8 220 LR4 Example 2 Comparative x 4 445 LR5 Example 3 Comparative x 8 220 LR5 Example 4

Experimental Examples: Measurement of Physical Properties of Antireflection Films

[0154] The following experiments were conducted for the antireflection films obtained in the examples and comparative examples.

[0155] 1. Measurement of Surface Energy of Hard Coating Film

[0156] The surface energies of the hard coating layers of each of the examples and comparative examples were measured by determining a contact angle of DI water (Gebhardt) and diiodomethane (Owens) at 10 points using a contact angle measuring apparatus DSA-100 (Kruss), calculating the average value, and then converting the average contact angle into the surface energy. In the measurement of the surface energy, the contact angle was converted into the surface energy by using Dropshape Analysis software and applying the following General Formula 1 of the OWRK (Owen, Wendt, Rable, Kaelble) method to the program.

.sub.L(1+cos )=2{square root over (.sub.S.sup.S.sub.L.sup.D)}+2{square root over (.sub.S.sup.P.sub.L.sup.P)}[General Formula 1]

[0157] 2. Measurement of Center Line Average Roughness (Ra)

[0158] The center line average roughness of the hard coating layer of each of the examples and comparative examples was measured according to the measurement standard concerning surface roughness (Ra) of JIS standard (JIS B 0601-1982). Specifically, aluminum-coated silicon tips (Bruker Corp.) were used at a scan speed of 0.5 to 0.8 Hz with Multimode AFM (MultiMode 8) equipment (Bruker Corp.). The hard coating layer sample of each of the examples and comparative examples (length*width: 1 cm*1 cm) was fixed on the AFM sample disk with a carbon tape, the measurement was performed while observing a flat portion with an optical microscope, and 3-point measured values in the area of 5 m*5 m were averaged, thereby obtaining the center line average roughness (Ra).

[0159] 3. Measurement of Antifouling Property

[0160] Three straight lines were drawn with a red permanent marker on the surface of the antireflection films obtained in the examples and comparative examples. Then, the antifouling property was evaluated through the number of erasing times when rubbing with a nonwoven cloth.

[0161] : Erase when rubbing 5 times or less

[0162] : Erase when rubbing 6 to 10 times

[0163] X: Erase or not erase when rubbing 11 times or more

[0164] 4. Measurement of Scratch Resistance

[0165] The surface of the antireflection films obtained in the examples and comparative examples was rubbed back and forth 10 times with steel wool (#0000) having a surface area of 20 mm*20 mm under a load at a speed of 10 cm/s. The scratch resistance was evaluated by confirming the maximum load at which a scratch of 1 cm or less was observed with the naked eye was 1 or less.

TABLE-US-00003 TABLE 2 Center line Surface average roughness energy (Ra) of the of hard surface of Anti- Scratch coating layer the hard coating fouling resistance [N/m] layer [nm] Property (g) Example 1 33 0.7 0 400 Example 2 33 0.7 0 400 Example 3 33 0.7 0 450 Example 4 33 0.7 0 450 Example 5 33 0.7 0 500 Example 6 32.11 0.7 0 500 Comparative 35.16 0.7 450 Example 1 Comparative 41.44 1.4 X 450 Example 2 Comparative 35.16 0.7 500 Example 3 Comparative 41.44 1.4 X 500 Example 4

[0166] As shown in Table 2, it was confirmed that the antireflection film of the examples had relatively excellent scratch resistance and at the same time had excellent antifouling properties. On the contrary, it was confirmed that the antireflection films of the comparative examples exhibited relatively poor scratch resistance and did not ensure a sufficient antifouling property.

[0167] Specifically, it was confirmed that, in the antireflection films of the examples using the hard coating in which center line average roughness (Ra) of the surface was 1.2 nm or less and surface energy was 34 mN/m or less, high scratch resistance and antifouling property could be realized at the same time and also relatively low reflectance, for example, average reflectivity of 0.7% or less could be realized.