KR101959476B1 - Anti-glare film and polarizing plate using the same - Google Patents

Abstract

More particularly, the present invention relates to an antiglare film, and more particularly, to an antiglare film, wherein the reflectance (%) in a remaining direction excluding light reflected in a direction of 8 degrees to the normal direction B is a reflectance parameter X defined by (A / B) x 100, where B is a value measured by using an integrating sphere to measure light reflected in all directions when light is incident on the surface of the antiglare film, Is in the range of 5 to 20.

Description

(ANTI-GLARE FILM AND POLARIZING PLATE USING THE SAME)

The present invention relates to an antiglare film and a polarizing plate having the film.

An image display apparatus includes a liquid crystal display (LCD), an electroluminescent (EL) display, a plasma display (PDP), a field emission display (FED), and the like.

When these various image display devices are exposed to external light such as natural light or illumination light, the light incident on the surface of the image display device is reflected, and the contrast is lowered. In addition, the screen becomes dazzling and difficult to recognize the characters, which easily increases the fatigue of the eyes or causes a headache.

In order to solve such a problem, an antiglare film having a function of inducing irregular reflection of light by the surface protruding portion to reduce reflection of light and disposed on the surface of various image display devices has been mainly used.

On the other hand, haze has been widely used as a method for evaluating the antiglare property of the antiglare film. Korean Patent Publication No. 2011-0124376 discloses that when Ha is defined as Ha and the internal haze value of the optical stack is defined as Hi, Ha is more than 0% and less than 90%, Hi is more than 0% and less than 90% Hs is not less than 0.1 and not more than 6.0, Sm is not less than 60 탆 and not more than 400 탆, and? A is not less than 0.1 and not more than 1.2 Or less and Rz is more than 0.2 탆 and not more than 1.2 탆.

However, since the haze does not clearly reflect the phenomenon of image degradation due to the reflection of external light in an actual display, the surface roughness value also does not clearly reflect the reflection phenomenon of the external light. There is a limit to the evaluation.

It is an object of the present invention to provide a liquid crystal display device which has a good reflectivity parameter (X) capable of reflecting an image degradation phenomenon due to reflection of external light, Film.

In order to achieve the object of the present invention, the present invention provides an antiglare film characterized by having a reflectance parameter (X) defined by Equation (1) is 5 to 20.

(A) is a value obtained by measuring the reflectance (%) in the other direction except for the light reflected in the direction of 8 ° with respect to the normal direction when the light is incident on the surface of the antiglare film, And the light reflected from all directions by the incident light is measured using an integrating sphere)

Preferably, the reflectance parameter X may be 7 to 15.

The antiglare film may have an antiglare layer comprising 15 to 80 parts by weight of a light transmitting resin and 0.5 to 30 parts by weight of light transmitting particles per 100 parts by weight of the whole composition for forming an antiglare layer.

The average particle diameter of the light transmitting particles may be 1 to 10 mu m.

The thickness of the antiglare layer may be 1 to 20 μm.

In order to achieve still another object of the present invention, there is provided a polarizing plate comprising the antiglare film.

The antiglare film according to the present invention satisfies the range of the reflectance parameter (X) in the range of 5 to 20, thereby having excellent antifogging property and at the same time improving the image degradation problem due to reflection of external light, Can be provided.

The present invention is an antiglare film characterized by having a reflectance parameter (X) of 5 to 20 as defined by the formula (1).

 [Equation 1]

(A) is a value obtained by measuring the reflectance (%) in the other directions except for the light reflected in the direction of 8 ° with respect to the normal direction when the light is incident on the surface of the antiglare film, using an integrating sphere. It shows the value measured by using the integrating sphere for the light incident on the light and reflected in all directions.

Reflected light in the other direction excluding light reflected in the direction of 8 ° to the normal direction of light incident on the surface of the antiglare film measured using the integrating sphere means light scattered on the surface of the antiglare film. Therefore, the reflectance parameter X is a parameter representing the amount of light scattered in the total light reflected from the surface of the antiglare film as a percentage.

In order to achieve the object of the present invention, the reflectance parameter X has a value of 5 to 20, preferably 7 to 15. When the reflectance parameter (X) is less than 5, there is a problem that the visibility is deteriorated and the display visibility is deteriorated when reflecting the external light. When the reflectance parameter (X) is more than 20,

The antiglare film is provided with an antiglare layer containing a composition for forming an antiglare layer comprising a light transmitting resin and translucent particles.

The light transmitting resin is a photosetting resin, and may include a photocurable (meth) acrylate oligomer and a monomer.

As the photocurable (meth) acrylate oligomer, epoxy (meth) acrylate, urethane (meth) acrylate and the like are commonly used, and urethane (meth) acrylate is more preferable. The urethane (meth) acrylate can be produced in the presence of a catalyst having a polyfunctional (meth) acrylate having a hydroxyl group in the molecule and an isocyanate group. Specific examples of the (meth) acrylate having a hydroxy group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl A mixture of pentaerythritol tetra (meth) acrylate, and a mixture of dipentaerythritol penta / hexa (meth) acrylate may be selected from the group consisting of lactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra Specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, Diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene-1, Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate And trifunctional isocyanate derived from trimethylene propanol adduct toluene diisocyanate O it may be one or more selected from the group consisting of carbonate.

The monomer is typically a photo-curable functional group having an unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group or an allyl group in the molecule, and among these, a (meth) acryloyl group is more preferable.

Specific examples of the monomer having a (meth) acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) (Meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipropylene glycol di (Meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tetra , Dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylate such as tripentaerythritol hexa (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl , Hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, iso-decyl (meth) acrylate, stearyl (meth) acrylate, tetrahydroperfuryl ) Acrylate, phenoxyethyl (meth) acrylate, and isobonole (meth) acrylate.

The light-curable (meth) acrylate oligomer and the monomers, which are the above-mentioned light-transmitting resins, may be used singly or in combination of two or more thereof.

The light transmitting particle is used in the art and can be used without any particular limitation as long as it is a particle capable of imparting a water repellency. Examples of the translucent particles include silica particles, silicone resin particles, melamine resin particles, acrylic resin particles, styrene resin particles, acryl-styrene resin particles, polycarbonate resin particles, polyethylene resin particles, Resin particles or the like can be used. The above-mentioned translucent particles may be used alone or in combination of two or more.

The average particle diameter of the light transmitting particles is preferably 1 to 10 mu m. When the average particle diameter of the light transmitting particles is less than 1 탆, it is difficult to form irregularities on the surface of the antiglare layer, resulting in lowering of the antiglare property. When the average particle diameter is more than 10 탆, the surface of the antiglare layer becomes coarse and visibility deteriorates.

The content of the light-transmitting resin and the light-transmitting particle preferably includes 1 to 20 parts by weight of light-transmitting particles per 100 parts by weight of the light-transmitting resin.

When the amount of the light-transmitting resin is less than 15 parts by weight, it may be difficult to improve the hardness sufficiently. When the amount is more than 80 parts by weight, coating properties may be poor. If the light transmitting particle is less than 0.5 weight part based on the above standard, the antireflection property may be deteriorated, and if it exceeds 30 weight part, the whitening phenomenon of the antiglare layer may be increased.

The composition for forming an antiglare layer may further include a photoinitiator. The photoinitiator may be any of those used in the art. Specific examples of the photoinitiator include 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinepropanone-1, diphenylketone benzyldimethylketal, 2- 4-phenylacetophenone, 4-hydroxycyclopentene, 4-hydroxycyclophenyl ketone, dimethoxy-2-phenyl aetetophenone, anthraquinone, fluorene, triphenylamine, carbazole, At least one selected from the group consisting of 4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexyl phenyl ketone and benzophenone can be used.

The photoinitiator may be used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the entire composition for forming a hard coat layer. If the content of the photoinitiator is less than 0.1 parts by weight, the curing rate is slow. If the content of the photoinitiator is more than 10 parts by weight, cracking may occur in the hard coat layer.

The composition for forming an antiglare layer may be diluted with a solvent to improve dispersibility and coatability, and may be used without limitation as long as it is known as a solvent for a composition for forming a coating layer in the technical field.

Specific examples of the solvent include alcohols (methanol, ethanol, isopropanol, butanol, methylcellulose, ethylsorbox), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, Etc.), hexane (hexane, heptane, octane etc.), benzene (benzene, toluene, xylene, etc.) and the like can be used alone or in combination of two or more.

The content of the solvent may be 10 to 95 parts by weight based on 100 parts by weight of the total amount of the composition for forming a light-shielding hard coat layer. If the amount of the solvent is less than 10 parts by weight, the viscosity of the composition is low, and if the amount of the solvent exceeds 95 parts by weight, the curing process is time-consuming and economical.

The antiglare layer may be formed by coating a solution prepared by diluting the composition for forming an antiglare layer with a solvent on one side of a transparent substrate film, followed by drying and UV curing. The thickness of the antiglare layer is preferably 1 to 20 mu m.

The present invention provides a polarizing plate provided with the antiglare film according to the present invention. That is, the polarizing plate of the present invention may be formed by laminating an antiglare film according to the present invention on one side or both sides of a conventional polarizer. The polarizer may have a protective film on at least one side thereof.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples, but the following examples are only specific examples of the present invention and are not intended to limit or limit the scope of protection of the present invention.

Example  One

20 parts by weight of urethane acrylate (product of MIWON Co., Ltd., product of PU620), 20 parts by weight of pentaerythritol triacrylate (product of MIWON Corporation, product of M340), 2 parts by weight of translucent particles (acryl-styrene copolymer, Sekisui Tec polymer Co., refractive index 1.51, (Average particle diameter: 4.5 μm), 20 parts by weight methyl ethyl ketone (purified gold), 27 parts by weight propylene glycol monomethyl ether (purified gold), 2.5 parts by weight photoinitiator (product of Shibasa, I-184) (BYK 3550, product of BYK 3550) were mixed using a stirrer and filtered using a PP filter to prepare a composition for forming an antiglare layer.

The above-prepared flame-retardant hard-coating composition was coated on a 60-μm triacetylcellulose (TAC) film to a resin thickness of 3.8 μm, and then the solvent was dried at 70 ° C. for 2 minutes. The dried film was irradiated with ultraviolet rays at a total light quantity of 400 mJ / cm ² to prepare an antiglare film having an antiglare layer.

Example  2

An antiglare film was produced in the same manner as in Example 1, except that the resin thickness was 4.3 탆.

Example  3

An antiglare film was prepared in the same manner as in Example 1, except that the resin thickness was 4.0 占 퐉.

Example  4

An antiglare film was prepared in the same manner as in Example 1 except that the translucent particles were silicone resin particles (Momentive, Tospearl 145, refractive index 1.43, and 4.5 um).

Example  5

An antiglare film was prepared in the same manner as in Example 1 except that the resin thickness was 3.0 占 퐉.

Comparative Example  One

An antiglare film was prepared in the same manner as in Example 1 except that the resin thickness was 2.0 탆.

Comparative Example  2

An antiglare film was prepared in the same manner as in Example 1, except that the resin thickness was 5.0 占 퐉.

The reflectance (A, B) was measured using a spectrophotometer (Konica Minolta Co., CM-3700d) after bonding a black acrylic plate to the back surface of the above-prepared antiglare film.

Reflectance (A) in the other direction except for light reflected in the direction of 8 ° from normal direction due to incident light on the surface of the antiglare film and reflection in all directions except light reflected in all directions (B) was measured using an integrating sphere. Specifically, the reflectance (A, B) was measured with an ISO standard d / 8 structure, and the reflectance (A) was measured by a SCE method at intervals of 10 nm from 360 nm to 740 nm using a pulse xenon lamp and a 6 inch integrating sphere. The reflectance (A, B) measured according to the wavelength was converted into the Y value calculated by the CIE 1931 standard colorimetric system.

Using the measured A and B values, the reflectance parameter (X) defined by Equation (1) is calculated and shown in Table 1 below.

A B A / B Example 1 4.52 0.43 9.50 Example 2 4.62 0.23 5.00 Example 3 4.55 0.32 7.00 Example 4 4.50 0.68 15.00 Example 5 4.48 0.90 20.00 Comparative Example 1 4.46 1.12 25.00 Comparative Example 2 4.69 0.09 2.00

Experimental Example

The physical properties of the light-scattering hard coating film prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1. The measurement method and evaluation method are as follows.

(One) Blooming  Film Hayes  Measure

The haze values of the antiglare films prepared in the above Examples and Comparative Examples were measured using a HZ-1 Haze Meter of Suga Co., The haze of the coating film correlates with the turbidity of the coating film, and the higher the haze, the sharper the film.

(2) Blooming  Measurement of transparency of film

In the above Examples and Comparative Examples, the antiglare film was bonded to a black acrylic plate, and the clarity of transparency was measured using a sharpness meter (ICM-1T, Suga). Reflectance sharpness was calculated by adding the values at slit intervals of 0.25 mm, 0.5 mm, 1.0 mm and 2.0 mm. The transmission sharpness value correlates with the blackness, and the higher the transmission sharpness value, the better the blackness.

- Assessment Methods -

Transparency sharpness 200 to 400: Black very good

Transparency sharpness 100 to less than 200: Good blackness

Transparency sharpness Less than 100: Black

(3) Blooming  Film Cloudiness Moxie  evaluation

The antiglare films prepared in Examples and Comparative Examples were bonded to a black acrylic plate, and then the light of the three-wavelength stand was reflected from the surface of the antiglare film to confirm the appearance of the stand light.

- Assessment Methods -

◎: The shape of the stand light is distorted and the boundary line can not be found

○: The shape of stand light is distorted and is recognized.

Flickering X: The shape of the stand light is clearly visible

Hayes
(%) Cloudiness Transparency sharpness
(%) Black Example 1 2.3 ◎ 254.00 Very good Example 2 1.10 ○ 311.00 Very good Example 3 4.30 ◎ 288.00 Very good Example 4 12.30 ◎ 217.00 Very good Example 5 8.50 ◎ 176.00 Good Comparative Example 1 5.20 ◎ 43.00 Lowering Comparative Example 2 0.70 X 380.00 Very good

Claims (6)

An antiglare film comprising an antiglare layer comprising 5 to 80 parts by weight of a light transmitting resin and 0.5 to 30 parts by weight of light transmitting particles based on 100 parts by weight of the whole composition for forming an antiglare layer,
Wherein the antiglare film has a reflectance parameter (X) of 7 to 15 and a transmittance sharpness of 100 to less than 400%, which is defined by Equation (1).
[Equation 1]

(A and B are the values measured by the ISO standard d / 8 structure, where A is the angle of incidence of light in the other direction except for the light reflected in the direction of 8 degrees from the normal direction, Reflectance (%) is measured by using an integrating sphere, and B represents a value measured by using an integrating sphere, in which light is incident on the surface of the antiglare film in an unspecified direction and reflected in all directions)
delete delete The antiglare film according to claim 1, wherein the average particle diameter of the light transmitting particles is 1 to 10 μm.
The antiglare film according to claim 1, wherein the antiglare layer has a thickness of 1 to 20 μm.
A polarizing plate comprising the antiglare film according to any one of claims 1, 4 and 5.