KR20110075495A - Antiglare film - Google Patents

Abstract

PURPOSE: An antiglare film is provided to ensure black brightness, anti-glare, and excellent sparkling and to prepare an excellent optical film with no change of haze and visibility. CONSTITUTION: An antiglare film comprises a transparent substrate and an antiglare coating layer formed on at least one side of the transparent substrate. Spherical particles of the coating layer satisfies the relational expression: 0.7&amp;times;(4πr^2) <= Sa <= 1.5&amp;times;(4πr^2), wherein Sa is the surface area of the spherical particle; and r is the radius of the spherical particle. The spherical particle is one of acryl, polystyrene, melamine or silica.

Description

Anti-glare Film with Excellent Anti-glare {ANTIGLARE FILM}

The present invention relates to an anti-glare film, and in particular, black luminance, sparkling as well as anti-glare, and in order to produce an excellent optical film having no haze change and visibility change after the anti-glare film is produced, the surface area and radius are in a constant relationship. It is related with the anti-glare film which used the spherical particle which exists in the coating layer.

In the case of typical LCD surfaces such as mobile displays, laptops, monitors, and TVs, antiglare films are installed on the display surfaces to prevent glare and improve visibility. The antiglare film is formed by coating a resin containing silica particles having a size of several μm on the surface of a transparent base film. In addition, in order to increase the anti-glare property of the anti-glare film, there is a problem in that the haze of the coating layer increases and the sharpness and visibility of the display decreases. However, if the internal haze effect is realized like a light diffusion film, the surface is almost flat, and thus the external light of the display cannot be left unattended. Therefore, recently, in order to solve this problem, as described in Patent No. 3507719, a translucent organic diffusing agent (spherical particle) having a different refractive index from a translucent resin is coated on the antiglare layer to prevent haze due to surface irregularities and internal haze due to diffusion inside the coating layer. Implement.

However, the anti-glare film such as Patent No. 3507719 has a high surface haze of 7 to 30%, so that the entire display has a white haze phenomenon, and the density of black is lowered, thereby lowering the contrast of the display. In addition, since the average particle diameter d of the light-transmitting diffusing agent is 0.1 µm ≤ d ≤ 5 µm, the surface irregularities of the coating layer are inevitably increased, so that the haze value increases and the visibility is deteriorated.

The present invention has been invented to solve the above problems, the present invention is excellent in black brightness, sparkling as well as anti-glare and after the anti-glare film is produced to produce an excellent optical film with no haze change and visibility change An object of the present invention is to provide an anti-glare film having excellent anti-glare property using spherical particles having a constant radius in a coating layer.

The anti-glare film having excellent anti-glare according to the present invention comprises a transparent substrate and a coating layer formed on at least one surface of the transparent substrate to implement anti-glare, the spherical particles in the coating layer is characterized by satisfying relation 1 .

0.7 × (4πr²) ≤ Sa ≤ 1.5 × (4πr²) --------- Relationship 1

Sa: surface area of spherical particles

r: radius of the spherical particle

According to another preferred feature of the invention, the spherical particles are any one of acrylic, polystyrene, melamine or silica.

Anti-glare film according to the present invention is excellent in black brightness, sparkling as well as anti-glare, it is possible to produce an excellent optical film without a change in haze and visibility after the anti-glare film is produced.

Antiglare film in the present invention comprises a transparent substrate and a coating layer.

As long as the transparent base material used for this invention is a plastic film with transparency, any film can be used, For example, the cycloolefin type which has a unit of the monomer containing a cycloolefin, such as a norbornene or a polycyclic norbornene-type monomer, Derivatives, diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, cellulose such as acetyl propionyl cellulose or polycycloolefin, polyester, Polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether Ketones, polyetherethers One or more thermoplastic polymers such as leketone, polyethersulfone, polymethylmethacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, epoxy, and the like can be selected and used, and not stretched. Uniaxial or biaxially oriented films can be used. Among these, there is no uniaxial or biaxially stretched polyester film having excellent transparency and heat resistance, a cycloolefin derivative film, a polymethyl methacrylate film, and transparency and optically anisotropy, which are excellent in transparency and heat resistance and can cope with the enlargement of the film. A triacetyl cellulose and an isobutyl ester cellulose film are more preferable at the point. Although the thickness of the said transparent base film is not specifically limited, It is preferable that it is 8-1000 micrometers, and it is more preferable that it is 40-100 micrometers. When the thickness of the transparent base film is less than 8 μm, the strength of the film is lowered, resulting in poor workability. When the thickness of the transparent base film is greater than 1000 μm, transparency is reduced or the weight of the polarizing plate is increased.

The coating layer is a layer that is coated on top of the transparent substrate to implement anti-glare, the coating layer includes a plurality of spherical particles. In general, the particles in the coating layer that form the surface irregularities and implement the internal haze are spherical particles that are easy to manufacture, and porous particles having fine pores on the surface of the particles may be used to control surface properties and refractive index.

Such spherical particles form anti-corrosion properties by forming surface irregularities of the coating layer, and spherical particles are composed of organic or inorganic particles. Acrylic, polystyrene, melamine, etc. are single or a copolymer is mentioned as organic particle | grains, Silica is mentioned as an inorganic particle.

The coating layer has a concave-convex shape on the outermost surface due to spherical particles. In the present invention, in order to produce an anti-glare film having excellent surface properties of black brightness, sparkling (sparkling) and anti-glare, the spherical particles used in the coating layer uses particles satisfying the following relationship.

0.7 × (4πr²) ≤ Sa ≤ 1.5 × (4πr²) ---------- Relationship 1

Where Sa is the surface of the spherical particles in the coating layer, and r is the radius of the spherical particles.

Here, when the surface area Sa of the spherical particles in the coating layer that forms the surface irregularities and implements the internal haze is less than 0.7 × (4πr²), the shape of the particles is more amorphous than the spherical shape, and the contact area between the particles is larger, resulting in greater dispersibility of the particles. Poor and surface irregularities cause sparkling and black brightness decreases. In addition, when the surface area Sa of the particles in the coating layer exceeds 1.5 × (4πr²), fine pores on the surface of the particles increase, so that the haze change and visibility after the anti-glare film is produced by remaining in the fine pores of the solvent in the coating solution. Side effects such as change occur. However, in the present invention, it can be seen that there exists an optimal correlation value of the surface area Sa of the spherical particles in the coating layer. When the spherical particle Sa value in the coating layer satisfies the range of 0.7 × (4πr²) ≤ Sa ≤ 1.5 × (4πr²), it is excellent in black brightness, sparkling and anti-glare, and there is no change in haze and visibility after the anti-glare film is manufactured. An optical film can be manufactured.

<Examples>

 [Examples 1 to 4 and Comparative Examples 1 to 4]

Preparation of Anti-glare Coating Composition and Anti-glare Film

According to the composition of Table 1, the resin (urethane acrylate UV curing resin) to the organic solvent (toluene, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), n-butanol (n-Butanol) After sufficiently mixing and dissolving, a photoinitiator (product name: IGC-184D, manufacturer: Ciba) and fine particles (Soken, spherical, 3㎛) were further mixed in order to prepare an anti-glare coating composition.

The anti-glare coating composition was applied to a triacetyl cellulose (TAC) film (manufacturer: Fuji, thickness: 80 μm), and then dried at 80 ° C. for 1 minute. At this time, the thickness of the dried coating film was 5 ~ 7㎛. An anti-glare film was prepared by irradiating the dried coating film with ultraviolet (500 mJ / cm 2). The average spacing (Sm) and average roughness (Ra) of the irregularities of the prepared antiglare film were measured using a surface roughness tester (3D) manufactured by Toyo, and glossiness (60 ° Gloss, unit:%) was measured . It was measured by BYK-Gardner's micro gloss meter, and screening was evaluated by attaching an antiglare film to the monitor, visually confirming the crushing of the screen cells, and black luminance (unit: cd / m ² ) was measured by A black insulating tape (manufacturer: 3M, product name: # 1711) was attached to the back side and measured using a Minolta measuring device (product name: CS 2000). The results are shown in Table 2 below.

<Table 1>

Binder Particle Size Particle Surface Area (Sa) solvent Photoinitiator Detailed composition UV curing type
Monomer, Oligomer 3 μm
(Spherical Particles) Μm² Toluene, MEK, MIBK IC-184D
(Ciba company) Example 1 30-40% 5% 7.2πμm² 60-70% 0.2%        2 30-40% 5% 9πμm² 60-70% 0.2%        3 30-40% 5% (porous particles) 10.8πμm² 60-70% 0.2%        4 30-40% 5% (porous particles) 12.6π㎛² 60-70% 0.2% Detailed composition UV curing type
Monomer, Oligomer 3 μm
(Spherical Particles) Μm² Toluene,
MEK,
MIBK IC-184D
(Ciba company) Comparative Example 1 30-40% 5% 4.5πμm² 60-70% 0.2%        2 30-40% 5% 5.4πμm² 60-70% 0.2%        3 30-40% 5% (porous particles) 14.4πμm² 60-70% 0.2%        4 30-40% 5% (porous particles) 18πμm² 60-70% 0.2%

After mixing the composition for 1 hour or more, the TAC film is dried and then coated to have a thickness of 5 to 7 μm, dried at 80 ° C. for 1 minute, and cured by irradiating UV light 500mJ under nitrogen supply.

<Table 2>

particle
Radius (㎛) particle
Surface area (㎛²) Particle Surface Area / 4πr² Hayes
% Change Black luminance
(cd / ㎡) Sparkling Example 1 1.5 7.2 0.8 0 0.6 Good        2 1.5 9 One 0 0.5 Good        3 1.5 10.8 1.2 0.5 0.4 Good        4 1.5 12.6 1.4 One 0.4 Good Comparative Example 1 1.5 4.5 0.5 0 1.2 With        2 1.5 5.4 0.6 0 0.9 With        3 1.5 14.4 1.6 6 0.5 Good        4 1.5 18 2 20. 0.4 Good

The above table shows that when amorphous particles having a small surface area Sa value of less than 0.7 × (4πr²) in the coating layer were used, the haze change rate was good, but the dispersibility of the particles was poor, resulting in poor optical properties such as black brightness and sparkling. (Comparative Examples 1 and 2)

In addition, when the spherical porous particles having a larger surface area Sa value of 1.5 × (4πr²) in the coating layer were used, the optical properties such as black brightness and sparkling were good, but the haze change rate was large, resulting in problems of quality change such as visibility. (Comparative Examples 3-4)

Therefore, when the spherical particle Sa value in the coating layer satisfies the range of 0.7 × (4πr²) ≤ Sa ≤ 1.5 × (4πr²), it is excellent in black brightness, sparkling as well as anti-glare and changes in haze and visibility after the anti-glare film is manufactured. The optical film can be prepared.

※ The surface area Sa of the particles was measured by CE Instruments Pascal Series M.

※ The haze change rate (%) of the anti-glare film which was completed was calculated | required by measuring the haze before and after leaving a film for 24 hours at 20 degreeC ± 2 room temperature with the NDH-2000 haze meter.

※ The black luminance was measured by Minolta CS 2000 with a black insulating tape (3M, ＃ 1711) attached to the back of the antiglare film.

※ Sparkling evaluation was performed by attaching antiglare film to Samsung monitor 214TS model and visually evaluating the presence or absence of sparkling.

1 and 2 are SEM images of the anti-glare film coating layer using spherical particles satisfying the relation of relation 1 as in Examples 1 and 2, and FIGS. 3 and 4 are Sa ≧ 1.5 × (4πr²). SEM image of the antiglare film coating layer using particles having a relationship of.

1 and 2 are SEM images of the antiglare film coating layer using spherical particles satisfying the relationship of relation 1 as in Examples 1 and 2,

3 and 4 are SEM images of the antiglare film coating layer using particles having a relationship of Sa ≧ 1.5 × (4πr²).

Claims (3)

In the antiglare film comprising a transparent substrate and a coating layer formed on at least one surface of the transparent substrate to implement anti-glare property, Spherical particles in the coating layer is an anti-glare film, characterized in that to satisfy the relation 1. 0.7 × (4πr²) ≤ Sa ≤ 1.5 × (4πr²) --------- Relationship 1 Sa: surface area of spherical particles r: radius of the spherical particle The anti-glare film of claim 1, wherein the spherical particles are any one of acryl, polystyrene, melamine or silica. The anti-glare film of claim 1, wherein the transparent base material has a thickness of 8 to 1000 µm.

Images