KR101675569B1 - Protective film - Google Patents

Abstract

The present invention relates to a protective film in which two or more transparent plastic substrates provided with a functional coating layer are laminated through an adhesive layer.

Description

Protective Film {PROTECTIVE FILM}

The present invention relates to a protective film in which a transparent plastic substrate having a functional coating layer formed thereon is laminated through an adhesive layer, and relates to a protective film having excellent total light transmittance and low water permeability.

The present invention also relates to a protective film for an e-book to which a touch screen method is applied.

E-paper is a display that has the most similar characteristics to ordinary paper. It is a next-generation display that not only displays information but also freely writes and erases data.

An e-book based on the principle of electronic paper has also been developed. The electronic book is composed of a driving film formed on a glass and a protective film for protecting the driving film.

In addition, as the electronic book industry develops, it is required not only to display information but also to freely write and erase data and to store data. In order to more easily utilize these functions, the touch screen method has been applied. A touch screen type electronic book requires a protective film that stably and stably operates even in a contaminated environment.

Accordingly, the protective film for protecting the electronic book or the touch screen type electronic book can be shock-mitigated, and is required to withstand moisture and UV. Thus, development of such a protective film is required.

Disclosed is a protective film for use in an e-book, which is resistant to moisture and has excellent UV barrier properties.

The present invention also provides a protective film having scratch prevention and anti-glare functions.

The present invention also provides a protective film having excellent total light transmittance.

The present invention relates to a protective film for use in an electronic book.

More specifically, the present invention relates to an optical information recording medium comprising an antiglare coating layer, a first transparent plastic substrate, a first adhesive layer, a second transparent plastic substrate, a first silicon oxide (SiOx, x is 1.0 to 2.0) coating layer, , A second silicon oxide (SiOx, x is 1.0 to 2.0) coating layer, and an acrylic resin coating layer are successively laminated, and the total light transmittance is 89 to 91%, the moisture permeation rate (MVTR) is 0.01 g / Is 6 to 10%.

Particularly, the present invention is characterized by the lamination sequence, and prevents glare and scratches by preventing the anti-glare layer from being formed in the outermost layer. In addition, the first and second silicon oxide coating layers and the second silicon oxide coating layer are laminated so as to face each other, and the second transparent plastic substrate having the first silicon oxide coating layer formed thereon and the third transparent plastic substrate having the second silicon oxide coating layer formed thereon (SiOx, x is 1.0 to 2.0) coating layer, a second adhesive layer, a third transparent plastic substrate, a second silicon oxide (SiOx, x is 1.0 to 2.0), and a second silicon oxide Coating layer in this order, it was surprisingly confirmed that the moisture permeability became very low. In particular, when laminated in the lamination sequence according to the present invention, the MVTR exhibits remarkable effects of 0.01 g / m 2 · day or less. When the moisture permeation rate is low, the electronic elements (e-book) Since the ink can display a screen close to black, the moisture permeability is a very important factor in the protective film for electronic books.

Further, it has been found that an acrylic resin coating layer can provide a protective film having an excellent total light transmittance, thereby completing the present invention.

Further, the protective film of the present invention is characterized not only by the order of lamination but also by its thickness, and by adjusting the thickness of each layer to a specific range, it has been found that a protective film with improved moisture permeability can be provided. The protective film prepared by the lamination procedure and thickness of the present invention has a moisture permeability of 0.5 g / m 2 · day or less and a UV transmittance of 2.0% or less under the conditions of 38 ± 2 ° C. and 100% RH (KS M 3088: 2004) The total light transmittance is 89 to 91%, the moisture permeability (MVTR) is 0.01 g / m < 2 > day or less, and the haze is 6 to 10%.

The protective film according to the present invention has a moisture permeability which is excellent for use in an electronic book, a change with time of the electronic ink is small, and the aging of the film can be prevented.

Hereinafter, the present invention will be described more specifically with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: FIG.

1, an anti-glare coating layer 11 is formed on a first surface of a first transparent plastic substrate 10, a first anti-glare coating layer 11 is formed on a first surface of a second transparent plastic substrate 20, A coating layer 21 of silicon oxide (SiOx, x is 1.0 to 2.0) is formed, and a second silicon oxide (SiOx, x is 1.0 to 2.0) coating layer 31 is formed on one surface of the third transparent plastic substrate 30 An acrylic resin coating layer 32 is formed on the second silicon oxide (SiO x, x is 1.0 to 2.0) coating layer 31 and the first transparent plastic substrate 10 and the second transparent plastic substrate 20, The first and second transparent plastic substrates 30 and 30 are disposed so as to face each other and are bonded to each other through the second adhesive layer 200 Thereby improving moisture permeability.

Hereinafter, the configuration of the present invention will be described in more detail.

In the present invention, the first transparent plastic substrate 10, the second transparent plastic substrate 20, or the third transparent plastic substrate 30 preferably uses a plastic material having a light transmittance of 90% or more. For example, a polyethylene terephthalate resin, a polyethylene naphthalate resin, or the like can be used. In addition, they may be stretched.

Although the first transparent plastic substrate 10 is not limited to being a support for the protective film, the first transparent plastic substrate 10 has a sufficient thickness as a support when the thickness is 50 to 250 탆, preferably 100 to 188 탆, , And flexibility can be maintained.

The second transparent plastic substrate 20 and the third transparent plastic substrate 30 serve as a support for the silicon oxide coating. However, when the thickness of the second transparent plastic substrate 20 is 10 to 50 탆, more preferably 12 to 30 탆, It is suitable to serve as a support in the deposition process, and appearance damage such as wrinkles does not occur.

In the present invention, the anti-glare coating layer 11 may be formed by mixing silicon beads with a hard resin such as acrylic urethane resin or siloxane resin, thereby achieving anti-glare and anti-scratch effects. If the thickness of the anti-glare coating layer 11 is small, the hardness becomes insufficient. If the anti-glare coating layer 11 is too thick, a crack may occur. In order to prevent curl from occurring, it is preferably 3 to 5 mu m.

In the present invention, the first silicon oxide coating layer 21 or the second silicon oxide coating layer 31 may be formed using a vacuum deposition method. When the x value is less than 1.0, the transparency of the silicon oxide (SiO x, x is 1.0 to 2.0) coating layer is lowered and the light transmittance becomes 90% or less. When the value exceeds 2.0, cracks may be generated. . The thickness of the silicon oxide coating layer is preferably from 300 to 1,000 angstroms, more preferably from 400 to 800 angstroms, since the moisture resistance is excellent and the transparent color can be maintained.

In the protective film of the present invention, the first adhesive layer (100) is preferably an adhesive composition composed of an acrylic resin and preferably contains a UV blocking agent. The first adhesive layer 100 of the present invention preferably has a light transmittance of 90% or more, a haze of 1% or less, and a shear storage elastic modulus of 10 ³ to 10 ⁵ Pa. If the light transmittance of the adhesive layer is 90% or less or the haze is 1% or less, the clarity of the display is lowered when the display is implemented. If the shear storage elastic modulus is less than 10 ³ Pa, the adhesive layer is pushed out during punching, If it exceeds 10 < ⁵ > Pa, there is a problem that durability is deteriorated due to low adhesive strength and the shock absorbing function is weakened.

The adhesive composition may further contain 0.5 to 5 parts by weight of a triazole-based UV blocking agent based on the solid content of the resin in order to secure a UV blocking function in a wide area. When the content of the triazole-based UV blocking agent is less than 0.5 part by weight, the UV transmittance after the QUV test rapidly increases, and the response speed may be slowed due to damage to the driving layer in the electronic book. If the content exceeds 5 parts by weight, A change in the value may occur. Examples of triazole-based UV blocking agents include benzotriazole, methylenebis (hydroxyphenylbenzotriazole) derivatives, and hydroxiphenylenebenzotriazole. In addition, triazine based UV blocking agents, antioxidants, heat stabilizers, fluorescent whitening agents, and the like which are conventionally used in the field can be further added as needed. These may be added within a range not lowering the physical properties of the film, and preferably 0.5 to 5 parts by weight based on the solid content of the resin. Examples of the triazine type UV blocking agent include hydroxysphenol triazine, 2,4,6-tris (diethyl 4'-aminobenzalmalonate) -s-triazine, 2,4,6-tris (diisopropyl 4 -Aminobenzal malonate) -s-triazine, 2,4,6-tris (dimethyl 4'-aminobenzalmalonate) -s-triazine, 2,4,6-tris (ethyl α- 4-aminocinnamate) -s-triazine, 2,4,6-tris [(3'-benzotriazol-2-yl-2'- Azine, 2,4,6-tris [(3'-benzotriazol-2-yl-2'-hydroxy-5'-ter-octyl) phenylamino] -s-triazine and the like can be used. In addition, antioxidants, heat stabilizers, and fluorescent whitening agents can be used without limitation as long as they are commonly used in the field.

The adhesive composition used in the first adhesive layer of the present invention may further comprise a crosslinking agent in addition to the acrylic resin. By the blending of the crosslinking agent, the crosslinking treatment can be performed to improve the heat resistance and the water resistance. As the crosslinking agent, those having reactivity with the functional group of the acrylic resin are preferably used. Examples of the crosslinking agent include a peroxide, an isocyanate crosslinking agent, an epoxy crosslinking agent, a metal chelate crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent and a metal salt. These crosslinking agents may be used alone or in combination of two or more. Of these cross-linking agents, isocyanate-based cross-linking agents are preferable from the viewpoint of adhesiveness. Examples of the isocyanate crosslinking agent include diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, diisocyanate adducts modified with various polyols, isocyanurate rings , A buret resin, or a polyisocyanate compound formed with an allophanate compound. Further, in the aromatic isocyanate compound, since the pressure-sensitive adhesive layer after curing may be colored, in an application requiring transparency, an isocyanate-based crosslinking agent is preferably an aliphatic or alicyclic isocyanate compound. The blending amount of the crosslinking agent is usually 0.01 to 10.0 parts by weight, preferably 0.05 to 5.0 parts by weight, based on 100 parts by weight of the acrylic adhesive. If the amount of the crosslinking agent is more than 10.0 parts by weight, the crosslinking becomes excessive, and the tacking property after the drying process is reduced, resulting in poor adhesion properties after laminating with the transparent plastic substrate, resulting in poor durability. When the crosslinking agent is less than 0.01 parts by weight, do.

The first adhesive layer 100 is formed by applying an adhesive composition onto a support and drying the adhesive composition. Since the adhesive contains a crosslinking agent, the crosslinking treatment is carried out by an appropriate heat treatment. The crosslinking treatment may be carried out at the temperature of the drying step of the solvent, or may be carried out after the drying step by forming a separate crosslinking step. The adhesive layer may be subjected to an aging treatment for the purpose of adjusting the crosslinking reaction of the adhesive layer.

In the present invention, the first adhesive layer (100) functions to improve impact absorption characteristics between the first transparent plastic substrate and the second transparent plastic substrate. In order to exert this function better, a shear storage elastic modulus of 10 ³ to 10 ⁵ Pa is used.

In the present invention, the second adhesive layer 200 uses an urethane-based adhesive excellent in adhesion to silicon oxide.

The adhesive composition used for the first adhesive layer or the second adhesive layer of the present invention can be used as a liquid composition. Examples of the solvent to be used include solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, isopropanol, And the like. These solvents may be used alone or in combination of two or more kinds. As the solvent, besides the polymerization solvent can be used as it is, at least one solvent other than the polymerization solvent may be newly added so that the adhesive layer can be applied uniformly.

In the present invention, the acrylic resin coating layer 32 formed on the third transparent plastic substrate 30 is used to improve the total light transmittance. The composition of the coating liquid for forming the acrylic resin coating layer is not limited as long as it is a composition for increasing the adhesive strength. Specifically, the coating solution may contain 10-15 wt% of an acrylic binder resin, 0.01-1 wt% of a wetting agent, 0.1-2 wt% of a particle, 0.1-3 wt% of a curing catalyst, 0.01-1 wt% of an antioxidant, And 1 to 5% by weight of an organic solvent is preferably used.

Examples of the acrylic binder resin include a resin selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, n-acrylate, ethyl methacrylate, acrylamide, butyl acrylate and glycidyl methacrylate May be used. The acrylic resin preferably has a T _g of 40 ° C to 50 ° C because it has a curing speed advantage. Further, the refractive index of the acrylic binder resin is preferably 1.4 to 4.5, more preferably 1.44 to 1.45, because it is advantageous for the transmittance compensation.

The particles can be inorganic or organic particles and can increase the light transmittance by increasing the light diffusibility due to the difference in refractive index. Of particles to be used is precipitated calcium carbonate (CaO), the colloidal silica particles, barium sulfate (BaSO _4), sodium (NaO _2), sodium sulfate and an anti-blocking inorganic particles, such as (Na ₂ SO _4), china clay, kaolin, talc oxide, Crosslinked acrylic resins and crosslinked polystyrene resins such as silicone resins, crosslinked divinylbenzene polymethacrylates and crosslinked polymethacrylates, benzoguanamine-formaldehyde resins, benzoguanamine-melamine-formaldehyde resins, melamine-formaldehyde resins And the like. More preferably, it is preferable to use one having an average particle diameter of 150 to 200 nm because of its excellent dispersibility and coating properties.

The curing catalyst may be an epoxy, an isocyanate, or the like. The organic solvent is used for improving the wettability. Specific examples thereof include isopropyl alcohol, propanol, and the like.

In the present invention, the acrylic resin composition preferably has a solid content of 1 to 15% by weight and a viscosity of 20 cps (25 캜) or less. If the concentration of the solid content is less than 1 wt%, the amount of the wet coating must be increased to obtain the thickness of the desired coating layer, and a large amount of energy is required to dry the wet coating to increase the manufacturing cost. When the concentration of the solid content exceeds 15 wt% , The viscosity increases to 15 cps (25 캜) or more, and the coating property may be lowered. The dry coating thickness is preferably 70 to 90 nm because the change of the refractive index of the protective film is small.

Since the protective film according to the present invention has low moisture permeability, it can minimize the elapsed time change of the electronic ink when applied as a protective film for an electronic book, and can prevent aging of the driving film due to low UV transmittance.

Further, the protective film of the present invention can provide a protective film having a total light transmittance of 89% or more.

The protective film of the present invention can be used not only in electronic books, but also in display devices such as home appliances, automobiles, communication devices, and PDAs.

Fig. 1 shows a first specific example of the protective film according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the following examples.

Hereinafter, the method of measuring the physical properties in the examples is as follows.

1) Water vapor permeability: Measured by KS M3088: 2004 (38 ± 2 ℃, 100% R.H.).

 Failed: moisture permeability exceeded 0.5

 Pass: Less than 0.5

2) UV transmittance: Measured using a Varian, Cary 5000 UV-visible spectrophotometer.

UV transmittance before QUV: The UV transmittance was measured in the entire UV wavelength range (200 to 300 nm) after the anti-glare coating layer of the first transparent plastic was directed toward the UV light source after the protective film was produced. A value indicating the highest UV transmittance in the measured range was used.

Fail: over 2.0

Pass: less than 2.0

- UV transmittance (%) after QUV: After the protective film was prepared, the surface of the first transparent plastic substrate was oriented toward the light source in a QUV chamber equipped with a lamp that emits UVB wavelength, and after standing for 100 hours, the UV transmittance UV transmittance was measured in the ~ 300 nm UV wavelength range. A value indicating the highest UV transmittance in the measured range was used.

Fail: over 2.0

Pass: less than 2.0

3) Shear Stiffness

The adhesive layer composition used in the preparation of the protective film was dissolved in a solvent and then applied to a Teflon sheet by a solvent casting method, and the solvent was blown off to prepare a 1 mm thick film having only an adhesive layer. The adhesive layer film thus prepared was placed on the center of a stationary bottom plate and a rotatable top plate using a Rheometer (Rheometrics, RMS), and the change in shear force according to the frequency (the angle at which the upper plate moved at a unit time) Were measured. At this time, the data was measured in a range of 1 to 100 radian / sec with a strain of 5%, and then the storage elasticity value at 10 radian / sec was used as a reference value.

4) Coating thickness: Measured using a thickness meter.

5) Appearance: Visually inspected, passed without any apparent abnormality, and rejected with wrinkle.

6) Light transmittance of protective film: The light transmittance was measured by using a total transmittance value measured using a 300A model of Nippon Denshoku. When the light transmittance of the protective film was 88% or more, , And if it is less than 60%, it is marked as defective.

7) Haze: Haze and light transmittance were measured in a visible ray region with a haze meter (TOYOSEIKI, Japan) according to ASTM D1003.

8) Moisture permeability (MVTR): Water permeability for 24 hours at 38 ° C × RH 100% was measured by PERMATRAN-WModel 398 (Mocon, USA).

[Example 1]

Preparation of first transparent plastic substrate having anti-glare coating layer

A polyethylene terephthalate film (Kolon, H11F) having a thickness of 188 mu m and a width of 1000 mm was prepared. 5 parts by weight of silica beads (Shinetsu Chemical, X-52-854) were added to 100 parts by weight of an acrylic urethane resin (DAI NIPPON PRINTING, Unidec 17-824-9) To prepare a composition for use in the antiglare layer. This composition was coated on one side of the polyethylene terephthalate film and dried at 100 DEG C for 3 minutes and immediately irradiated with ultraviolet rays with an ozone type high pressure mercury lamp (80 W / cm, 15 cm light condensing type) Blocking layer.

Production of second transparent plastic substrate having first silicon oxide coating layer formed

A 500 Å thick SiO _1.5 coating layer was formed on a polyethylene terephthalate film (Kolon, FQ00) having a thickness of 12 μm and a width of 1000 mm by a vacuum deposition method.

Production of a third transparent plastic substrate having a second silicon oxide deposition layer and an acrylic resin coating layer formed thereon

A 500 탆 thick SiO _1.5 coating layer was formed on a polyethylene terephthalate film having a thickness of 12 탆 and a width of 1000 탆 by a vacuum deposition method.

12.5 g of an acrylic binder (refractive index: 1.44, glass transition temperature: 48 캜), 0.1 g of a silicone-based wetting agent (polyester siloxane copolymer of TEGO Co.), 0.4 g of colloidal silica particles having an average particle diameter of 200 nm, ), 0.29 g of an antioxidant (benzotriazole type), 80.97 g of water and 5 g of isopropyl alcohol were mixed to prepare an acrylic resin composition having a solid concentration of 5% and a viscosity of 30 cps.

The acrylic resin composition was coated on the silicon oxide coating layer at a dry coating thickness of 80 nm.

Preparation of first adhesive composition

0.3 part by weight of an isocyanate crosslinking agent (Sokenna, E-AX) was added to 100 parts by weight of a solid content of an acrylic adhesive (Sokenna, SK2094R), and 1 part by weight of benzotriazole (Ciba, Tinuvin 1130) , And methyl ethyl ketone was added to the solution so that the solid content of the solution became 20% to prepare an adhesive composition.

Preparation of second adhesive composition

20 parts by weight of an isocyanate curing agent (KANJAN HWASUNG CL 100) was added to 100 parts by weight of a polyurethane resin (neoforce 338) solids, and the mixture was diluted with a toluene solvent to prepare a solution having a solid content of 10%.

Production of protective film

As shown in FIG. 1, a second transparent plastic substrate having a first silicon oxide coating layer formed thereon, a second silicon oxide coating layer, and a third transparent plastic substrate having an acrylic resin coating layer formed thereon were bonded using a second adhesive composition. This was again adhered to the first transparent plastic substrate having the anti-glare layer formed thereon with the first adhesive composition.

Specifically, the second adhesive composition was coated on the surface of the second transparent plastic substrate on which the first silicon oxide coating layer was formed, and then dried at 100 캜 for 2 minutes to form a second adhesive layer having a dry coating thickness of 3 탆. Thereafter, the third transparent plastic substrate side of the third transparent plastic substrate on which the second silicon oxide coating layer was formed was adhered so as to face the second adhesive layer.

The first adhesive composition was coated on the surface of the second transparent plastic substrate on which the first silicon oxide coating layer was not formed, and then dried at 100 ° C for 3 minutes to form a first adhesive layer having a coating thickness of 50 μm. The surface of the first transparent plastic substrate on which the anti-glare layer was not formed was bonded thereto.

The protective film thus prepared was used to measure physical properties. The results are shown in Table 1 below.

[Example 2]

A protective film was prepared in the same manner as in Example 1, except that the solid content in the acrylic resin coating layer was changed to 1.2 wt%.

The protective film thus prepared was used to measure physical properties. The results are shown in Table 1 below.

[Example 3]

A protective film was prepared in the same manner as in Example 1, except that the solid content in the acrylic resin coating layer was 1.0 wt%.

The protective film thus prepared was used to measure physical properties. The results are shown in Table 1 below.

[Comparative Example 1]

A protective film was prepared in the same manner as in Example 1, except that the order of lamination was different. That is, the first silicon oxide coating layer and the second silicon oxide coating layer were adhered so as to face the second adhesive layer.

Specifically, the second adhesive composition was coated on the surface of the second transparent plastic substrate on which the first silicon oxide coating layer was formed, and then dried at 100 ° C for 2 minutes to form a second adhesive layer having a dry coating thickness of 3 μm. Thereafter, the surface of the second silicon oxide coating layer of the third transparent plastic substrate was attached so as to face the second adhesive layer.

The first adhesive composition was coated on the surface of the second transparent plastic substrate on which the first silicon oxide coating layer was not formed, and then dried at 100 ° C for 3 minutes to form a first adhesive layer having a coating thickness of 50 μm. The surface of the first transparent plastic substrate on which the anti-glare layer was not formed was bonded thereto.

The protective film thus prepared was used to measure physical properties. The results are shown in Table 1 below.

[Comparative Example 2]

A protective film was prepared in the same manner as in Example 1, except that the acrylic resin coating layer was not provided.

The protective film thus prepared was used to measure physical properties. The results are shown in Table 1 below.

[Table 1]

As shown in the table, it can be seen that the moisture permeation rate of the embodiment according to the present invention is very low. This is because, in Comparative Example 1, when the first oxide coating layer and the second oxide coating layer are bonded using the polyurethane adhesive, the inorganic oxide is affected by the residual adhesive solvent. In order to prevent such deterioration of physical properties, the present invention achieves a very excellent moisture permeability of not more than 0.01 g / m < 2 > day by changing the layer structure.

Therefore, it has been found that the protective film having the lamination sequence and the thickness according to the present invention has a good water vapor barrier property and good UV shielding property and can be easily applied to protective films for electronic books and other applications.

It was also found that the total light transmittance was improved as compared with Comparative Example 2 in which the acrylic resin coating layer was not formed.

DESCRIPTION OF THE DRAWINGS -
10: First transparent plastic substrate
11: Anti-glare coating layer
20: second transparent plastic substrate
21: First silicon oxide coating layer
30: Third transparent plastic substrate
31: Second silicon oxide coating layer
32: Acrylic resin coating layer
100: first adhesive layer
200: second adhesive layer

Claims (8)

(SiOx, x is 1.0 to 2.0) coating layer, a second adhesive layer, a third transparent plastic substrate, a second silicon substrate, (MVTR) of not more than 0.01 g / m < 2 > day, a haze of 6 to 10%, and a coating layer of an oxide (SiOx, x is 1.0 to 2.0) and an acrylic resin coating layer sequentially. In protective film. The method according to claim 1,
Wherein the acrylic resin coating layer comprises 10 to 15 wt% of an acrylic binder resin having a refractive index of 1.4 to 1.5 and a glass transition temperature of -10 to 20 캜, 0.01 to 1 wt% of a wetting agent, 0.1 to 2 wt% 0.1 to 3% by weight of an antioxidant, 0.01 to 1% by weight of an antioxidant, 80 to 85% by weight of water and 1 to 5% by weight of an organic solvent. The method according to claim 1,
Wherein the silicon oxide coating layer is coated to a thickness of 300 to 1,000 angstroms by vacuum deposition. The method according to claim 1,
Wherein the anti-glare coating layer is coated with a dry coating thickness of 3 to 5 占 퐉 by using a composition comprising an acrylic urethane resin and silicone beads. The method according to claim 1,
The first adhesive layer is coated with a dry coating thickness of 30 to 60 占 퐉 using an acrylic adhesive composition containing a UV blocking agent and the second adhesive layer is coated with a urethane adhesive composition coated with a dry coating thickness of 1 to 10 占 퐉 film. 6. The method of claim 5,
Wherein the first adhesive layer has a light transmittance of 90% or more, a haze of 1% or less, and a shear storage elastic modulus of 10 ³ to 10 ⁵ Pa. The method according to claim 1,
Wherein the thickness of the first transparent plastic substrate is 50 to 250 占 퐉, the thickness of the second transparent plastic substrate is 10 to 50 占 퐉, and the thickness of the third transparent plastic substrate is 10 to 50 占 퐉. 8. The method of claim 7,
Wherein the first transparent plastic substrate, the second transparent plastic substrate, or the third transparent plastic substrate is made of polyethylene terephthalate or polyethylene naphthalate having a light transmittance of 90% or more.

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