KR200423846Y1 - Photo diffusion film - Google Patents

Abstract

20-40% by weight of organic particles are added to the softened UV curable resin to form a light diffusion layer having a thickness of 5-30 μm on the entire surface of the plastic substrate, and organic particles to the softened UV curable resin. It is added to 3-10% by weight to provide a light diffusion film consisting of a blocking prevention layer formed on the back of the plastic substrate coated with a thickness of 1-20㎛, so that the light diffusion effect is excellent while the surface is smooth and does not appear curling phenomenon.

Light diffusion layer, anti-blocking layer, oligomer, monomer, organic particles, light diffusion film, UV curing

Description

Light Diffusion Film {PHOTO DIFFUSION FILM}

1 is a cross-sectional view showing a light diffusion film according to the present invention

* Description of the symbols for the main parts of the drawings *

DESCRIPTION OF SYMBOLS 1: Plastic base material 3: Light-diffusion layer

5: blocking prevention layer

The present invention relates to a light diffusion film, and more particularly, using a softened ultraviolet curable resin and adding 20-40% by weight of organic particles to the total weight to form a light diffusion layer and an antiblocking layer on the front and back of the film, respectively. The present invention relates to a light diffusing film having excellent light diffusion effect and smooth surface and no curling phenomenon.

The light diffusing film diffuses, reflects and refracts the light from the fluorescent lamp of the back light unit to diffuse the light and spread the light evenly throughout the LCD screen. do.

The manufacturing method of such a light diffusing film can be largely divided into a thermosetting method and an ultraviolet curing method.

Among them, the thermosetting method is difficult to use a material that is deformed at a high temperature due to the high temperature hardening, and the energy consumption is high to harden, which is expensive. In addition, since the heating oven is large, the installation area is large, and the curing time is several minutes to several hours and requires 72 hours of post-curing process, resulting in poor productivity and uniformity of the product. In addition, the use of isocyanate as a crosslinking agent tends to shift the color index of the product to yellow, and the formation of foreign substances due to the detachment of the coating agent during drying in the process acts as a cause of deterioration of product quality.

Ultraviolet curing method is a curing method that absorbs ultraviolet rays by photo-initiator in the paint component and shows reactivity, and then reacts with monomer or oligomer to cause polymerization. Compared with its excellent storage stability and hardening in seconds at room temperature, it is also an important coating technology used in various fields due to its excellent productivity.

The light diffusion film manufacturing method using the ultraviolet curable resin has been introduced in part of the Republic of Korea Patent Publication No. 10-2005-0004231, etc., but due to some problems are not applied to the actual production process.

Looking at the above problems, when a coating film of a predetermined thickness or more is laminated on one surface of the transparent plastic substrate, curling of the substrate occurs due to shrinkage of the coated coating film during UV curing. The high hardness of the resin used causes cracking and foreign matters in the coating film during cutting of the diffusion film.In addition, the organic particles are introduced at low weight ratio, so that the matting or matting effect is given priority over the actual light diffusion function. In many cases, it was impossible to apply the light diffusion film due to the deterioration of the film.

An object of the present invention for solving the above problems is to use a softened UV curable resin and add 20-40% by weight of organic particles to the total weight to form a light diffusion layer and a blocking prevention layer on the front and back of the film, respectively The excellent light diffusion effect, smooth surface and no curling phenomenon.

A feature of the present invention for achieving the above object is a light diffusion layer formed by coating 20-50% by weight of the organic particles in the flexible UV curable resin with a total thickness of 5-30㎛ on the front surface of the plastic substrate, and Organic light is added to the softened UV curable resin by 3-10% by weight based on the total weight to provide a light diffusion film composed of a blocking prevention layer formed on the back of the plastic substrate to a thickness of 1-20㎛, while excellent in light diffusion effect The surface is smooth and no curling occurs.

An embodiment of the present invention having the features as described above will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a light diffusing film according to the present invention, the light diffusion layer 3 is formed on the front surface of the plastic substrate 1 to a coating thickness of 5-30㎛, the anti-blocking layer ( 5) The coating is formed to a thickness of 1-20 μm.

In the above constitution, the light diffusion layer is 20-40% by weight of organic particles added to 60-80% by weight of the softened UV-curable resin, and the blocking layer is 3-10% by weight of organic particles of 90-97% by weight of the softened UV-curable resin. It is added by weight.

On the other hand, an ultraviolet curable resin consists of an oligomer, a monomer, a photoinitiator, an organic solvent, and a dispersing agent, and softening the said ultraviolet curable resin consists of mixing an oligomer, a monomer, a photoinitiator, and an organic solvent suitably.

Of these, oligomers include acrylates such as epoxy acrylates, urethane acrylates, polyester acrylates, silicone acrylates, polyether acrylates, polyol acrylates, and melamine acrylates, epoxy resins, polyester methacrylates, and polyethers. 5-20 weight% of methacrylates, such as methacrylate, unsaturated polyesters, and styrene resins are used.

Examples of the monomer include acrylic acid esters such as 2-ethyl methylhexyl acrylate, methoxyethyl acrylate and butyl acrylate, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, dipropylene glycol diacrylate, ethylene glycol acrylate and propylene glycol. Polyfunctional compounds such as dimethacrylate and diethylene glycol dimethacrylate, substituted amino alcohol esters of unsaturated acids such as 2-ethyl acrylate, styrene monomers such as styrene and C-methyl styrene, and trimetholpropane 2-10 weight% of polythiol compounds, such as a trithio acrylate, a trimethol propane tri thio lorophilate, and a Venterierythritol tetrathioglycol, are used.

The photopolymerization initiator is camphorquinone, alpha-naphthol, benzyl, 2,4-diethylthioquixanthone, tri methylbenzoyl diphenylsulpinoxide, dimethylaminoethyl methacrylate, n-butylamine, triethylamine, 4-dimethyl 1 to 5% by weight of aminobenzoic acid isoamyl, hydrosilanes and sulfonylhydrazide derivatives are used.

Organic solvents include ketones such as methyl ethyl ketone, acetone, methyl butyl ketone and methyl isobutyl ketone, alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, aromatic hydrocarbons such as benzene, toluene and xylene, ethyl acetate and butyl Ester, such as acetate, is used by mixing at 40 to 80% by weight.

Organic particles are classified into monodisperse organic particles with uniform particle size distribution and particle size, polydisperse organic particles with uniform particle size distribution and particle size, and include polymethyl methacrylate, ethyl methacrylate, normal butyl methacrylate, Olefins such as isobutyl methacrylate, acrylamide, methrolacrylamide, glycidyl methacrylate, ethyl acrylate, normal butyl acrylate, isobutyl acrylate, and olefins such as polyethylene, polystyrene, and polypropylene. 40 weight percent is used.

Dispersant is used 2-7% by weight.

Hereinafter, an example of the composition of the light diffusion layer and the blocking prevention layer for manufacturing the light diffusion film according to the present invention will be described.

< Example 1 >

Transparent polyester film (A4300, 125,188㎛, manufactured by TOYOBO Japan / XG531, 125,188㎛, manufactured by TORAY-SAEHAN / SH36H, 125,188㎛, SKC / FHSO, 125㎛, KOLON / Mitsubishi, Japan) , Applying anti-blocking layer coating liquid on one side of the polycarbonate film (LOFO Co., Ltd.) using a micro gravure, gravure, slot-die with a thickness of 10 ~ 100㎛ dried, cured and then the opposite side of the transparent polyester film The light diffusion layer coating solution is applied to a thickness of 1 ~ 50㎛ using micro gravure, gravure, slot-die, dried and cured to prepare a light diffusion film.

In the light diffusion layer, the urethane acrylate oligomer 10% by weight, acrylamide monomer 5% by weight, alpha-naphthol photoinitiator 2% by weight, methyl ethyl ketone 20% by weight, isopropyl alcohol 20% by weight, toluene 10% by weight, polymethyl It is composed of 28% by weight of methacrylate polydisperse spherical particles (average particle size 8 µm, MBX-8, manufactured by Sekisui, Japan), and 5% by weight of dispersant (Disperbyk-168, manufactured by BYK Chemie, Germany).

The antiblocking layer comprises 12% by weight of urethane acrylate oligomer, 6% by weight of acrylamide monomer, 2% by weight of alpha-naphthol photoinitiator, 28% by weight of methyl ethyl ketone, 28% by weight of methyl isobutyl ketone, 14% by weight of toluene, polymethylmetha It is composed of 5% by weight of acrylate polydisperse spherical particles (average particle diameter: 5 μm, MBX-5, manufactured by Sekisui, Japan), and 5% by weight of dispersant (Disperbyk-168, manufactured by BYK Chemie, Germany).

< Example 2 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared using the following coating liquid composition, and the light diffusion layer was 8% by weight of polyether methacrylate oligomer, 3% by weight of diethylene glycol dimethacrylate monomer, and tri 1% by weight of ethylamine photopolymerization initiator, 29% by weight of methyl ethyl ketone, 29% by weight of xylene, 25% by weight of polymethyl methacrylate polydisperse spherical particles (average particle diameter: 8 µm, MB30X-8, manufactured by Sekisui, Japan), dispersant 5% by weight (Disperbyk-169, manufactured by BYK Chemie, Germany),

The antiblocking layer comprises 10% by weight of polyether methacrylate oligomer, 4% by weight of diethylene glycol dimethacrylate monomer, 1% by weight of triethylamine photopolymerization initiator, 38.5% by weight of isopropyl alcohol, 38.5% by weight of toluene, polymethylmethacryl 3 weight% of late polydisperse spherical particles (average particle diameter: 5 mu m, MB30X-5, manufactured by Sekisui, Japan) and 5 weight% of a dispersant (Disperbyk-169, manufactured by BYK Chemie, Germany) are used.

< Example 3 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared with the following coating liquid composition.

The light diffusion layer comprises 12% by weight of polyester acrylate oligomer, 6% by weight of methoxyethyl acrylate monomer, 2% by weight of triethylamine photopolymerization initiator, 24.5% by weight of isopropyl alcohol, 24.5% by weight of benzene, polymethyl methacrylate polydisperse sphere 25 weight% of particles (average particle size: 8 µm, MB30X-8, manufactured by Sekisui, Japan), and 6 weight% of a dispersant (Disperbyk-164, manufactured by BYK Chemie, Germany),

The antiblocking layer comprises 14% by weight of polyester acrylate oligomer, 9% by weight of methoxyethyl acrylate monomer, 2% by weight of triethylamine photopolymerization initiator, 33% by weight of methyl alcohol, 33% by weight of toluene, polymethyl methacrylate polydisperse spherical particles 3 weight% (average particle diameter 5 micrometers, MB30X-5, the Japan Sekisui company make), and 6 weight% of a dispersing agent (Disperbyk-164, German BYK Chemie company) are used.

< Example 4 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared with the following coating liquid composition.

The light diffusing layer is 8% by weight of urethane acrylate oligomer, 3% by weight of ethylene glycol acrylate monomer, 1% by weight of trimethylbenzoyl diphenylsulpinoxide photoinitiator, 25% by weight of methyl ethyl ketone, 25% by weight of isopropyl alcohol, xylene 14 20% by weight, polymethyl methacrylate polydisperse spherical particles (average particle size 10㎛, MR-10HG, manufactured by Soken Japan), 4% by weight of dispersant (Disperbyk-161, manufactured by BYK Chemie, Germany),

The antiblocking layer comprises 10% by weight of urethane acrylate oligomer, 4% by weight of ethylene glycol acrylate monomer, 1% by weight of trimethylbenzoyl diphenylsulpinoxide photoinitiator, 30% by weight of methyl ethyl ketone, 30% by weight of methyl alcohol, 18% by weight of xylene %, 3% by weight of polymethyl methacrylate polydisperse spherical particles (average particle diameter: 5 mu m, MR-7HG, manufactured by Soken Japan), and 4% by weight of dispersant (Disperbyk-161, manufactured by BYK Chemie, Germany) are used.

< Comparative Example 1 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared with the following coating liquid composition.

The light diffusion layer is 10% by weight urethane acrylate oligomer, 5% by weight acrylamide monomer, 2% by weight alpha-naphthol photoinitiator, 24% by weight methyl ethyl ketone, 24% by weight methyl isobutyl ketone, 12% by weight toluene, polymethylmetha 18% by weight of acrylate polydisperse spherical particles (average particle size: 8 μm, MBX-8, manufactured by Sekisui, Japan), 5% by weight of dispersant (Disperbyk-168, manufactured by BYK Chemie, Germany),

The antiblocking layer comprises 12% by weight of urethane acrylate oligomer, 6% by weight of acrylamide monomer, 2% by weight of alpha-naphthol photoinitiator, 28% by weight of isopropyl alcohol, 28% by weight of ethyl acetate, 14% by weight of toluene, polymethylmethacrylate. It is composed of 5% by weight of polydisperse spherical particles (average particle size: 5 mu m, MBX-5, manufactured by Sekisui, Japan), and 5% by weight of dispersant (Disperbyk-168, manufactured by BYK Chemie, Germany).

< Comparative Example 2 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared with the following coating liquid composition.

The light diffusion layer comprises 6% by weight of polyether methacrylate oligomer, 5% by weight of ethylene glycol acrylate monomer, 1% by weight of 2,4-diethylthiokisanthone photoinitiator, 31.5% by weight of methyl ethyl ketone, 31.5% by weight of toluene, poly It is composed of 20% by weight of methyl methacrylate polydisperse spherical particles (average particle size 8㎛, MB30X-8, manufactured by Sekisui, Japan), 5% by weight of dispersant (Disperbyk-169, manufactured by BYK Chemie, Germany),

The antiblocking layer comprises 8% by weight of polyethermethacrylate oligomer, 6% by weight of ethylene glycol acrylate monomer, 1% by weight of 2,4-diethylthioquixanthone photoinitiator, 38.5% by weight of methyl ethyl ketone, 38.5% by weight of xylene, It is composed of 3% by weight of polymethyl methacrylate polydisperse spherical particles (average particle diameter: 5 μm, MB30X-5, manufactured by Sekisui, Japan), and 5% by weight of dispersant (Disperbyk-169, manufactured by BYK Chemie, Germany).

< Comparative Example 3 >

Using the same conditions and methods as in Example 1, a light diffusion film was prepared with the following coating liquid composition.

The light diffusion layer comprises 12% by weight of urethane acrylate oligomer, 6% by weight of acrylamide monomer, 3% by weight of alpha-naphthol photoinitiator, 28% by weight of methyl ethyl ketone, 28% by weight of isopropyl alcohol, 14% by weight of toluene, silica spherical particles 5 It is composed of weight% (average particle size 4.0㎛, SYLOID C803, manufactured by GRACE Davison), and 4% by weight of dispersant (Disperbyk-161, manufactured by BYK Chemie, Germany).

Haze (%) Total light transmittance (%) Luminance (cd / m ² ) Example 1 88.4 98.7 4741 Example 2 89.4 97.1 4698 Example 3 88.6 97.6 4685 Example 4 90.1 98.6 4727 Comparative Example 1 81.3 92.8 4537 Comparative Example 2 76.8 88.2 4529 Comparative Example 3 84.2 86.4 4474

Table 1 above shows haze, total light transmittance, and luminance characteristics according to Examples 1 to 4 and Comparative Examples 1 to 3, and haze refers to the characteristics of the material in addition to reflection and absorption when light passes. The degree of opacity of the light that is diffused and opaque, and the luminance refers to the amount representing the brightness of the light source or the reflector surface of the light having a constant width.

According to the present invention configured as described above, a coating film having an appropriate thickness is laminated on the opposite side of the light diffusing layer to prevent curling and lower the roughness of the coated film using a softened UV curable resin to lower the light guide plate located at the bottom of the light diffusing film. Scratch is prevented from occurring and the hardness is lowered to a certain level by the use of softened UV curable resin, which causes cracking and foreign substances in the punching process, resulting in a drop in product yield. By suppressing this, there is no change in the mechanical properties of the light diffusing film, thereby obtaining a coating film having excellent flexibility and post-processing property.

In addition, the weight ratio of the organic particles was increased to improve optical properties such as haze, total light transmittance, and luminance.

Claims (3)

20-40% by weight of organic particles are added to the UV-curable resin, the light-diffusion layer having a coating thickness of 5-30㎛ on the front surface of the plastic substrate; 3-10% by weight of the organic particles to the ultraviolet curable resin is added to the total weight of the light diffusion film, characterized in that consisting of a blocking prevention layer formed in a thickness of 1-20㎛ coated on the back of the plastic substrate. According to claim 1, wherein the ultraviolet curable resin is composed of 5-20% by weight oligomer, 2-10% by weight monomer, 1-5% by weight photoinitiator, 40-80% by weight organic solvent and 2-7% by weight dispersant. Light diffusion film, characterized in that the softened. The light diffusing film of claim 1, wherein the organic particles use polydisperse organic particles.

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