Low refractive layer and anti-reflective film comprising the same
The present invention relates to a low refractive layer and an anti-reflective film comprising the same. The low refractive layer can exhibit excellent optical properties such as a low reflectance and a high light transmittance, and excellent mechanical properties such as high wear resistance and scratch resistance at the same time, without adversely affecting the color of the polymer resin forming the low refractive layer. In particular, due to the excellent alkali resistance, the low refractive layer can maintain excellent physical properties even after alkali treatment. Therefore, when introducing a low refractive layer to the display device, it is expected that the production process can be simplified and further the production rate and the productivity can significantly increase.
1. A low refractive layer, comprising a fluorine-based compound containing a group of —O—CF 2 CF 2 —O—CF 3 and 1% to 25% by weight of a polysilsesquioxane compound based on the solid content of the low refractive layer,
wherein the low refractive layer has a thickness of 1 nm to 300 nm,
wherein the low refractive layer has a refractive index of about 1.2 to 1.6, and
wherein the low refractive layer has b* values in a L*a*b* color coordinate system, which satisfy the following formula 1
0.5≥Δ b*=|b* 1 −b* 0 | [Formula 1]
in the formula 1,
b* 0 is a b* value in a L*a*b* color coordinate system as defined by the International Commission on Illumination as to the low refractive layer; and
b* 1 is a b* value in a L*a*b* color coordinate system as measured in the same manner as a method for measuring b* 0 as to the film prepared by immersing the low refractive layer for 2 minutes in 10 wt % sodium hydroxide aqueous solution heated to 30° C., washing the immersed layer with water, wiping off moisture, followed by immersing the wiped layer for 30 seconds in 10 wt % sodium hydroxide aqueous solution heated to 55° C., washing it with water and wiping off moisture.
2. The low refractive layer according to claim 1 , wherein the b* 0 value in the formula 1 is from 1 to −8.
3. The low refractive layer according to claim 1 , wherein the b* 1 value in the formula 1 is from 1.5 to −8.5.
4. The low refractive layer according to claim 1 , wherein the low refractive layer has S values which satisfy the following formula 2:
30%≥Δ S =[( S 0 −S 1 )/ S 0 ]×100 [Formula 2]
in the formula 2,
S 0 is the maximum load that scratches are not generated, when rubbing the surface of the low refractive layer while applying a load to a grade #0000 steel wool and reciprocating ten times at a speed of 24 rpm; and
S 1 is the maximum load that scratches are not generated, as measured in the same manner as a method of measuring S 0 with respect to the film prepared by immersing the low refractive layer for 2 minutes in 10 wt % sodium hydroxide aqueous solution heated to 30° C., washing the immersed layer with water, wiping moisture off, followed by immersing the resulting layer for 30 seconds in 10 wt it sodium hydroxide aqueous solution heated to 55° C., and then washing it with water and wiping moisture off.
5. The low refractive layer according to claim 4 , wherein the S 0 value in the formula 2 is from about 250 to 800 g.
6. The low refractive layer according to claim 4 , wherein the S 1 value in the formula 2 is from about 200 to 800 g.
7. The low refractive layer according to claim 1 , wherein the low refractive layer exhibits a minimum reflectance in the wavelength range of about 480 to 680 nm.
8. The low refractive layer according to claim 1 , wherein an average reflectance for light in the wavelength range of 380 to 780 nm is from 0.9 to 2.5%.
9. The low refractive layer according to claim 1 , wherein the low refractive layer further includes a photocured product of a coating composition comprising a photopolymerizable compound, inorganic particles and a photopolymerization initiator, and
wherein the polysilsesquioxane is substituted with at least one reactive functional group.
10. The low refractive layer according to claim 1 , wherein the b* 0 value in the formula 1 is from −2.27 to −8.
11. The low refractive layer according to claim 1 , wherein the b* 1 value in the formula 1 is from −1.84 to −8.5.
12. An anti-reflective film comprising the low refractive layer of claim 1 ; and a hard coating layer formed on one surface of the low refractive layer.
13. The anti-reflective film according to claim 12 , wherein the hard coating layer includes a binder resin containing a photocurable resin; and organic or inorganic fine particles dispersed in the binder resin.
14. The anti-reflective film according to claim 13 , wherein the organic or inorganic fine particles have a particle diameter of 1 to 10 μm.