KR20170091396A - Transparent barrier film - Google Patents

Abstract

The present invention relates to a transparent barrier film on which an inorganic layer and an inorganic oxide layer are sequentially laminated on a transparent base material film layer. Provided is the transparent barrier film formed with a polymeric protection layer on top of the inorganic oxide layer and a refractive index adjustment layer whose refractive index is adjusted within 1.3-1.5 on the other side of the transparent base material film layer. The transparent barrier film increases interlayer adhesiveness and gas barrier properties, protects the inorganic oxide layer from external scratches owing to the polymeric protection layer, and also exhibits excellent visible light transmittance as well as low moisture permeability while maintaining excellent interlayer adhesiveness, through regulation of thickness of thin films and low refractive index in the refractive index adjustment layer.

Description

Transparent barrier film {TRANSPARENT BARRIER FILM}

The present invention relates to a transparent barrier film, and more particularly, to a transparent barrier film comprising an inorganic oxide layer and an inorganic oxide layer sequentially laminated on a transparent base film layer, wherein a polymer protective layer is formed on the inorganic oxide layer, By forming the refractive index control layer of 1.3 to 1.5, the interlayer adhesion is improved by the inorganic layer, the gas barrier property is improved by the inorganic oxide layer, the inorganic oxide layer is protected from the external scratches by the polymer protective layer And a transparent barrier film that exhibits an excellent visible ray transmittance as well as a low moisture permeability while maintaining an excellent interlaminar adhesion due to the control of the refractive index and the thin thickness of the refractive index control layer.

The plastic substrate is lightweight, has excellent impact resistance, is inexpensive, and can be easily thinned. Therefore, the plastic substrate is effectively utilized as a substrate material in a large number of next generation electronic products related fields.

However, since the plastic substrate has higher gas permeability than glass, the display device using the plastic substrate as the substrate may cause degradation of the product with time due to permeation of oxygen or water vapor.

For example, a polyethylene terephthalate (PET) material used as a representative plastic substrate has a high oxygen permeability of 1500 g / m ² · day per 1 μm thickness and a high moisture permeability of 272 g / m ² · day per 1 μm thickness .

However, a specific display device using a display device, sensitive to the environment, typically the moisture permeability of up to 10 ^-4 to 10 ^-2 g / m ² · day and the oxygen transmission rate of up to 10 ^-5 to 10 ^-6 g / m ² · day in need.

In order to protect environmentally sensitive products from exposure to gases and liquids such as chemicals used in processing, handling, storage and use of products, and oxygen and water vapor in the environment, Barrier coatings have been attempted on substrates.

Japanese Patent No. 2556940 discloses a method of polycondensing a composition comprising a siloxane coupling agent such as an epoxy silane, such as Si (O-CH ₃ ) ₄ , and a polyvinyl alcohol, on a substrate made of a resin by a sol-gel method Thereby obtaining a laminated film. However, since the coating layer of the present invention is made of hydrogen bonds, it swells and dissolves in water, so that the gas barrier property tends to be deteriorated easily.

Japanese Patent Publication No. 63-28017 discloses a gas barrier laminate film having a vapor deposition film obtained by depositing an inorganic oxide such as silicon oxide, aluminum oxide, or magnesium oxide on a plastic film by means of a vacuum evaporation method, a sputtering method, or the like. Transparency and gas barrier properties such as oxygen and water vapor have been reported.

Accordingly, the conventional barrier film has a gas barrier layer made of an inorganic oxide thin film such as silicon oxide or aluminum oxide. Such a gas barrier layer can be formed by a plasma enhanced chemical vapor deposition (PECVD) method, a sputtering method And is coated on the surface of the plastic film by a vacuum deposition method such as sputtering or a sol-gel method.

However, since the gas barrier layer made of a thin film of silicon oxide or aluminum oxide is obtained by depositing inorganic oxide particles on a film, there is a gap called a grain boundary between the inorganic oxide particles and the gas barrier property of the thin film is insufficient, Should be. As a result, another problem arises that cracking is liable to occur due to the low degree of softness (softness).

In addition, the smaller the oxygen atom ratio of the inorganic oxide is, the better the gas barrier property is, while the transparency is lowered and the adhesion between the substrate and the inorganic oxide particles is weak.

The present inventors have made efforts to improve the problems of the conventional barrier film. As a result, the inventors of the present invention have found that an inorganic layer for improving adhesion is introduced on a plastic substrate and a polymer layer is formed on the inorganic oxide layer, By forming a protective layer to protect the inorganic oxide layer from external scratches and the like and to form a refractive index control layer on the back surface of the transparent base film layer, By confirming the physical properties of 90% or more, the present invention has been completed.

An object of the present invention is to provide a transparent barrier film having an optimized layer structure for improving transparency, interlaminar adhesion and gas barrier property.

The present invention relates to a transparent substrate film, which comprises a transparent substrate film layer, an inorganic layer and an inorganic oxide layer which are successively laminated, and which has a polymer protective layer formed on the inorganic oxide layer and a refractive index control layer having a refractive index of 1.3 to 1.5, Barrier film.

The refractive index control layer is adjusted to have a refractive index in the range of 1.3 to 1.5 by fluorine or organosilicon resin or hollow silica particles, and the thickness of the refractive index control layer is preferably in the range of 10 to 500 nm.

Further, the polymer protective layer is formed to a thickness of 0.1 to 10 mu m by wet coating, and protects the inorganic oxide layer from external scratches or the like.

In the transparent barrier film of the present invention, the inorganic layer is made of any one metal selected from Si or Al, and is formed with a thickness of 0.1 to 50 nm.

The inorganic oxide layer is made of an oxide of a metal selected from the group consisting of silicon, aluminum, zinc, tin, nickel, zirconium and titanium, and has a thickness of 10 to 100 nm.

The present invention can provide a transparent barrier film having an optimized layer structure for improving transparency, interlayer adhesion, and gas barrier property, in which an inorganic layer and an inorganic oxide layer are sequentially laminated on a transparent base film layer.

More specifically, a polymer protective layer is formed on the inorganic oxide layer to protect the inorganic oxide layer from external scratches and the like, and a refractive index control layer is formed on the back surface of the transparent substrate film layer so that a low water vapor permeability But an excellent visible light transmittance can be realized.

1 is a schematic cross-sectional view of a transparent barrier film according to the present invention.

1 is a cross-sectional schematic diagram of a transparent barrier film according to the present invention,

An inorganic layer (300) and an inorganic oxide layer (400) are sequentially stacked on a transparent base film layer (200)

A polymer protective layer 500 formed on the inorganic oxide layer 400,

And a refractive index control layer (100) having a refractive index of 1.3 to 1.5 formed on the back surface of the transparent base film layer (200).

Hereinafter, the characteristics of each layer will be described.

1) The refractive index control layer 100

In the transparent barrier film of the present invention, the refractive index control layer 100 is formed on the back surface of the transparent base film layer 200 in order to improve optical characteristics (transmittance).

Transmittance is one of the most important properties in the field of display films. For example, in the case of an LCD, the transmissivity of an applied film is improved, thereby providing an advantage of reducing brightness and reducing power consumption.

In order to satisfy the above requirements, the refractive index control layer 100 of the present invention is preferably adjusted to have a refractive index (n) in the range of 1.3 to 1.5, 10 to 80 wt% of the binder resin, 5 to 50 wt% % And 0.1 to 10% by weight of a photoinitiator are formed by wet coating from a polymer resin liquid contained in a solvent.

By the wet coating, the thickness of the refractive index control layer is preferably 10 to 500 nm, more preferably 10 to 300 nm, most preferably 10 to 100 nm thick, and when controlled to a low refractive index, While satisfying low visible light transmittance as well as low moisture permeability.

The inorganic particles for adjusting the refractive index used in the refractive index control layer 100 are particles capable of adjusting the refractive index or controlling the refractive index by controlling the content of the resin having a low refractive index such as fluororesin, and may be hollow or porous silica fine particles Can be used. On the other hand, the refractive index of the hollow silica particles is measured by an Abbe refractometer (manufactured by ATAGO K.K.).

The hollow silica particles may be prepared by a method known in Japanese Patent Application Laid-Open Nos. 2001-233611 and 2002-79616, or may be hollow silica particles commercially available.

The hollow fine particles used in the refractive index control layer 100 of the present invention preferably have an average particle size of 40 to 110 nm. At this time, if it is within the above range, the ratio of the cavities can be satisfactorily maintained and the refractive index can be sufficiently reduced.

The shape is most preferably spherical, but it can be a cubic, spindle-shaped, or irregular shape. Wherein the average particle diameter of the hollow silica particles can be determined from electron micrographs.

In addition, the fine particles used in the refractive index control layer 100 may be surface-treated with an organic compound such as a silane coupling agent, a polyol, an alkylol amine, or a titanate coupling agent to facilitate dispersion

2) The transparent base film layer 200

In the transparent barrier film of the present invention, it is preferable that the transparent base film layer 200 has a high light transmittance and a low haze value for use as a display device. For example, the light transmittance at a wavelength of 400 to 800 nm is preferably 60% or more, and more preferably 85% or more.

The haze value is 5% or less, more preferably 2% or less. When the above condition is not satisfied, the sharpness of the image is poor when used as the display display member. In order to exhibit such effects, the upper limit of the light transmittance can be set to about 99.5%, and the lower limit of the haze value can be set to about 0.1%.

The material of the transparent base film layer is not particularly limited and may be selected from known transparent base film materials. Preferable examples thereof include any one selected from among esters, ethylene, propylene, diacetate, triacetate, styrene, carbonate, methylpentene, sulfone, ether ethyl ketone, imide, fluorine, nylon, acrylate and alicyclic olefins Polymer or a copolymeric polymer containing units can be used.

More preferably, among these resins, a material excellent in transparency, strength and uniformity of thickness is selected from an ester type such as polyethylene terephthalate, an acetate type such as triacetyl cellulose and an acrylate type such as polymethyl methacrylate Is used as the polymer or copolymer. In particular, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polyethylene-a,? - bis (2-ethylhexyl) -Chlorophenoxy) ethane-4,4'-dicarboxylate, and the like.

It is also preferable that the above-mentioned polyester is copolymerized with another dicarboxylic acid component or diol component in an amount of not more than 20 mol%, and the polyester resin may be used singly or in combination of two or more thereof. , And most preferably polyethylene terephthalate.

The thickness of the transparent base film layer 200 is determined in consideration of the transparency, the haze value, and the mechanical characteristics, and is 5 to 800 탆, more preferably 10 to 250 탆, or two or more films may be bonded .

The transparent base film layer 200 can be subjected to various surface treatments. For example, the transparent base film layer 200 can be selectively subjected to a corona discharge treatment, a glow discharge treatment, a flame treatment, an etching treatment, a roughening treatment, or the like. In addition, a primer layer may be formed on the surface of the transparent base film layer 200 for promoting adhesion. Examples of the primer layer include a polyurethane, polyester, polyester acrylate, polyurethane acrylate, and polyepoxyacrylate , A titanate compound or the like, and then a high refractive index hard coat layer is formed.

3) Inorganic layer (300) and inorganic oxide layer (400)

In the transparent barrier film of the present invention, the inorganic layer 300 is introduced for the purpose of improving the adhesion between the transparent base film 200 and the inorganic oxide layer 400 and improving the gas barrier property, and the metal selected from Si or Al is selected Is used.

The thickness of the inorganic layer 300 is 1 to 50 nm, preferably 1 to 20 nm, and more preferably 1 to 10 nm.

In the transparent barrier film of the present invention, the inorganic oxide layer 400 preferably contains oxygen in order to improve the barrier property. Specifically, the inorganic oxide layer 400 includes oxygen, silicon oxide, oxynitride, oxycarbide and oxynitride carbide And the inorganic oxide layer 400 is formed to have a thickness of 10 to 1000 nm, more preferably 10 to 100 nm, and still more preferably 20 to 100 nm.

At this time, the refractive index of the inorganic oxide layer 400 is preferably from 1.4 to 1.55, and if the refractive index is less than 1.4, the possibility of interference fringes depending on the thickness variation increases, while if it exceeds 1.55, the transmittance becomes low.

The inorganic layer 300 and the inorganic oxide layer 400 are formed to improve the transparency and function as a transparent gas barrier layer.

The inorganic layer 300 and the inorganic oxide layer 400 may be formed by a physical vapor deposition (PVD) method such as vacuum deposition, ion plating, or sputtering, and a chemical vapor deposition (CVD) method.

4) Polymer protective layer 500

In the transparent barrier film of the present invention, the polymer protective layer 500 is formed to protect the inorganic oxide layer 400 from the handling environment.

That is, it serves to prevent the inorganic oxide layer 400 from being broken due to scratches, bending, etc., which occur during handling of the film.

At this time, the thickness of the polymer protective layer 500 is 0.1 to 10 탆, more preferably 1 to 5 탆. If the thickness of the polymer protective layer 500 is less than 0.1 탆, the pencil hardness tends to be lowered. If the thickness exceeds 10 탆, cracks occur during bending.

The polymer protective layer 500 satisfies the pencil hardness of 1H or more.

The polymer protective layer 500 of the present invention is formed by wet coating from a coating liquid contained in a remaining amount of solvent of 10 to 80% by weight of a binder resin. The curing method may be a UV curing method or a thermosetting method. (Meth) acrylate compound having an acidic functional group such as a carboxyl group, a phosphoric acid group, or a sulfonic acid group may be added in order to improve the adhesion with the inorganic oxide layer in the coating solution of the polymeric protective layer.

Specific examples of the monomer containing an acidic functional group include unsaturated carboxylic acids including acrylic acid, methacrylic acid, crotonic acid, 2-methacryloyloxyethylsuccinic acid, 2-methacryloyloxyethylphthalic acid and the like, mono (2 (Meth) acryloyloxyethyl) acid phosphate, diphenyl-2- (meth) acryloyloxyethyl phosphate, etc., and the like .

The transparent barrier film of the present invention in which the above-mentioned respective layer structures and the thickness thereof are optimized fulfills transparency and excellent interlayer adhesion at the same time while realizing an improved gas barrier property.

Specifically, the film after processing satisfies the following properties: (1) the transmittance is 90% or more; (2) the haze is 2% or less; and (3) the yellowness (b *) is 1% or less.

The transparent barrier film of the present invention satisfies the moisture permeability of the film after processing of not more than 0.5 g / m < 2 > day. In the layer structure, depending on the thickness of the inorganic layer 300 and the thickness of the inorganic oxide layer 400, Is different.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The present invention is intended to more specifically illustrate the present invention, and the scope of the present invention is not limited to these embodiments.

< Example  1>

On the transparent base film layer 200 using a polyethylene terephthalate film (XG7PL2 of Toray Advanced Material Co., Ltd.) having a thickness of 100 占 퐉 as a transparent base film, a 10 nm thick Si layer, a 50 nm thick SiO ₂ layer The inorganic layer 300 and the inorganic oxide layer 400 were formed.

A liquid containing a UV curable resin (LCH1587, manufactured by Toyoko Co., Ltd.) was coated on the inorganic oxide layer using a micro gravure coater and dried at 80 DEG C for 2 minutes. Thereafter, an integrated amount of light of 300 mJ / And a protective layer 500 of 1 mu m was formed by curing.

(Refractive index (n) = 1.38, average particle diameter of hollow silica: 60 nm) containing polyfunctional acrylic resin and hollow silica fine particles was coated on the back surface of the film with a micro gravure coater, After drying for several minutes, the coated layer was cured by irradiating a cumulative light quantity of 300 mJ / cm 2 of a high pressure mercury ultraviolet lamp to form a 40 nm refractive index control layer 100.

< Example  2>

A barrier film was prepared in the same manner as in Example 1 except that the thickness of the refractive index control layer 100 was changed to 70 nm.

< Example  3>

A barrier film was prepared in the same manner as in Example 1 except that the thickness of the refractive index control layer 100 was 100 nm.

< Example  4>

(PELNOX product, XJA-0262-48, refractive index (n) = 1.48, average particle size of silica particles: 20 nm) was coated with a microgravure coater as the refractive index controlling layer 100 at 80 캜 After drying for 2 minutes, a barrier layer was cured by irradiating a cumulative light quantity of 300 mJ / cm 2 of a high-pressure mercury ultraviolet lamp to form a refractive index control layer 100 having a thickness of 40 nm, A film was prepared.

< Example  5>

A barrier film was produced in the same manner as in Example 4 except that the thickness of the refractive index control layer 100 was changed to 70 nm.

< Example  6>

A barrier film was prepared in the same manner as in Example 4 except that the thickness of the refractive index control layer 100 was 100 nm.

< Example  7>

A refractive index (n) = 1.53) was applied as a refractive index controlling layer 100 by using a microgravure coater and dried at 80 DEG C for 2 minutes, and then the accumulated light quantity of the high pressure mercury ultraviolet lamp was changed to 300 mJ / And the coating layer was cured by irradiation to form a refractive index control layer 100 of 40 nm, a barrier film was produced in the same manner as in Example 1. [

< Example  8>

A barrier film was prepared in the same manner as in Example 7 except that the thickness of the refractive index control layer 100 was changed to 70 nm.

< Example  9>

A barrier film was produced in the same manner as in Example 7 except that the thickness of the refractive index control layer 100 was 100 nm.

< Example  10>

A barrier film was produced in the same manner as in Example 1 except that the thickness of the inorganic layer 300 was 20 nm.

< Example  11>

A barrier film was produced in the same manner as in Example 1 except that the thickness of the inorganic oxide layer 400 was 100 nm.

< Comparative Example  1>

A barrier film was produced in the same manner as in Example 11 except that the refractive index control layer 100 was not formed.

< Comparative Example  2>

A barrier film was produced in the same manner as in Example 11 except that the refractive index control layer 100 and the protective layer 500 were not formed.

< Comparative Example  3>

A barrier film was prepared in the same manner as in Example 11 except that the refractive index control layer 100, the inorganic layer 300 and the protective layer 500 were not formed.

From the results shown in the above Table 1, it can be seen that in the embodiment including Si as the inorganic layer 300, SiO ₂ as the inorganic oxide layer 400, the polymer protective layer 500, and the refractive index control layer 100 formed on the back surface of the substrate film 200 The physical properties of the barrier films 1 to 11 were compared with those of the barrier films of Comparative Examples 1 and 3, and as a result, the refractive index control layer was formed rather than the case where no refractive index control layer was formed, thereby improving the film transmittance. At this time, the film transmittance could be improved by adjusting the refractive index and thickness of the refractive index control layer 100.

The difference in adhesion between the substrate film 200 and the inorganic oxide layer 400 occurs depending on the presence or absence of the inorganic layer 300 and the polymer protective layer 500 is processed on the inorganic oxide layer 400 It is confirmed that the barrier property can be maintained by minimizing the breakage of the inorganic oxide layer by the above-mentioned method.

As described above, the present invention provides an organic EL device having an optimized layer structure for sequentially stacking an inorganic layer and an inorganic oxide layer on a transparent base film layer and improving transparency, interlayer adhesion and gas barrier property, A polymer protective layer and a refractive index control layer formed on the back surface of the transparent base film layer. That is, the polymer protective layer protects the inorganic oxide layer from external scratches and improves optical properties such as visible light transmittance and haze as well as low moisture permeability while maintaining excellent interlaminar adhesion by the refractive index control layer.

Thus, the transparent barrier film of the present invention satisfied the physical properties required for the conventional barrier film by optimizing the layer structure and the thickness thereof.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

100: refractive index control layer
200: transparent base film layer
300: inorganic layer
400: inorganic oxide layer
500: polymer protective layer

Claims (6)

An inorganic material layer and an inorganic oxide layer are sequentially laminated on the transparent base film layer,
A polymer protective layer formed on the inorganic oxide layer and
And a refractive index control layer having a refractive index of 1.3 to 1.5 formed on the back surface of said transparent base film layer. The transparent barrier film of claim 1, wherein the refractive index control layer is formed of fluorine or organosilicon resin or hollow silica particles. The transparent barrier film of claim 1, wherein the refractive index control layer is formed to a thickness of 10 to 500 nm. The transparent barrier film of claim 1, wherein the polymer protective layer is formed by a wet coating to a thickness of 0.1 to 10 mu m. The transparent barrier film of claim 1, wherein the inorganic layer is formed of a metal selected from Si or Al to a thickness of 0.1 to 50 nm. The transparent barrier film of claim 1, wherein the inorganic oxide layer is an oxide of a metal selected from the group consisting of silicon, aluminum, zinc, tin, nickel, zirconium and titanium to a thickness of 10 to 100 nm.

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