KR102017268B1 - Optical film and method for producing the same - Google Patents

Abstract

The present invention relates to an optical film and a method of manufacturing the same, comprising a first metal oxide layer, a metal layer and a second metal oxide layer sequentially on the substrate to block the moisture and oxygen penetrating into the metal layer to prevent the metal from being oxidized. can do. Specifically, the first and second metal oxide layers may be formed by using a specific material and a specific method to control visible light transmittance, and to block moisture and oxygen to prevent the metal of the metal layer from being oxidized. In addition, the metal layer may be formed of a pure metal to reduce the manufacturing cost of the optical film.

Description

Optical film and method for producing the same

The present invention relates to an optical film and a manufacturing method thereof, and to an optical film which minimizes defects caused by metal layer oxidation.

The solar control film of the window film can be classified into an absorbing film and a reflective film according to a method of blocking infrared rays. Generally, absorption solar control film is mainly used and reflective solar control film is used for high-end products. Reflective solar control film is a film having a low infrared transmittance by reflecting infrared rays, a typical structure in which a metal oxide layer and a metal layer are alternately stacked. Specifically, the metal oxide layer has two roles. The first is the role of the index matching layer (index matching layer) to adjust the visible light transmittance through the refractive index and thickness adjustment, the second is the role of the barrier layer to block the oxidation of the metal by blocking the moisture and oxygen.

The metal oxide layer of typical solar control films serves little as a barrier layer. Therefore, in order to prevent oxidation of the metal layer, an alloy containing metal having excellent durability is used instead of a pure metal. Specifically, APC (Ag-Pd-Cu) is used instead of silver. As a result, there is a problem that the solar control film price will rise.

Republic of Korea Registered Publication 10-1501423

It is an object of the present invention to provide an optical film having a low moisture permeability and oxygen permeability and a method of manufacturing the same.

The present invention,

A first metal oxide layer, a metal layer, and a second metal oxide layer sequentially formed on the substrate,

The water transmittance (WVTR) of the entire optical film is independently less than 400 mg / m ² day, and the oxygen transmission rate (OTR) is less than 0.3 cc / m ² day to provide an optical film.

In addition, the present invention,

Forming a first metal oxide layer on the substrate;

Forming a metal layer on the first metal oxide layer; And

It provides a method for producing an optical film comprising the step of forming a second metal oxide layer on the metal layer.

According to the present invention, the metal oxide layer is formed by a specific material and a specific method, thereby controlling the visible light transmittance as well as blocking moisture and oxygen to prevent the metal from being oxidized.

Specifically, the metal oxide layer serves as an index matching layer and a barrier layer, thereby obtaining a durable and transparent optical film. Unlike the conventional technologies using an alloy metal layer to produce an optical film having excellent weather resistance, the present invention can produce an optical film having excellent weather resistance even using a pure metal layer.

In addition, the use of pure metal in the metal layer can reduce the cost of manufacturing the optical film.

1 is a cross-sectional view of an optical film according to an embodiment of the present invention.
2 is a cross-sectional view of an optical film according to another embodiment of the present invention.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

In addition, it is to be understood that the accompanying drawings in the present invention are shown to be enlarged or reduced for convenience of description.

Hereinafter, the present invention will be described in detail.

Optical film according to an embodiment of the present invention,

A first metal oxide layer, a metal layer, and a second metal oxide layer sequentially formed on the substrate,

The optical transmittance (WVTR) of the optical film may be less than 400 mg / m ² day, and the oxygen transmittance (OTR) may be less than 0.3 cc / m ² day.

If the water transmittance (WVTR) of the optical film according to the present invention can be less than 400 mg / m ² day, specifically may be less than 300 mg / m ² day, more specifically less than 100 mg / m ² day. In particular, the moisture transmittance of the optical film may range from 0.1 to 10 mg / m ² day.

Oxygen transmittance (OTR) of the optical film according to the present invention may be less than 0.3 cc / m ² day, specifically less than 0.2 cc / m ² day, more specifically less than 0.1 cc / m ² day. In particular, the oxygen transmittance of the optical film may be in the range of 0.0001 to 0.01 cc / m ² day.

When the water transmittance and oxygen transmittance of the optical film according to the present invention are within the above ranges, it is possible to prevent metal layer oxidation and minimize defects such as discoloration due to metal layer oxidation.

The optical film according to the invention may have a transmittance of 60% or more, 65% or more or 70% or more for visible light, for example, light of any wavelength or 550 nm wavelength in the range of about 400 to 700 nm. Optical film satisfying the numerical range can be usefully used as a transparent film. However, the light transmittance of the visible light region of the optical film is not limited to the above numerical range, and may have a light transmittance of the visible light region that is generally applicable to the transparent electrode.

In addition, the optical film may have a transmittance of 5-30%, 20% or less, or 10% or less to an infrared region, for example, light of any wavelength within the range of about 800 to 2500 nm or more than 780 nm. Since the optical film satisfying the numerical range may block heat in the infrared region, for example, energy saving may be possible.

The optical film according to the present invention may include a first metal oxide layer, a metal layer and a second metal oxide layer, and characteristics such as light transmittance, moisture transmittance and oxygen transmittance in the visible and / or infrared region may be, for example. The thickness of the first metal oxide layer, the metal layer, and the second metal oxide layer may be controlled by a material, a forming method, a refractive index, a thickness, and the like.

In the present invention, the metal oxide layer may mean a layer containing an oxide as a main component, and the metal layer may mean a layer containing a metal as a main component. For example, the metal oxide layer may mean a layer including about 85 wt% or more of the metal oxide, and the metal layer may mean a layer including about 85 wt% or more of the metal.

The optical film according to the present invention may include a first metal oxide layer, a metal layer, and a second metal oxide layer sequentially formed on a substrate to minimize defects due to oxidation of the metal layer. Specifically, the first and second metal oxide layers may serve to adjust visible light transmittance through refractive index and thickness adjustment, and may prevent the metal of the metal layer from being oxidized by blocking moisture and oxygen.

It is preferable to use a material with good transparency, such as a plastic film, for a base material. For example, polyester-based resins, such as polyethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene terephthalate resin, acetate type resin, polyether sulfone type resin, polycarbonate type resin, polyimide type resin, and polyolefin type A film containing at least one synthetic resin selected from among resin, (meth) acrylate resin, polyvinyl chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin and polyphenylene sulfide resin can be used. have. In particular, the film containing polyester-based resin, such as high strength and low-cost polyethylene terephthalate resin, can be used.

The permeability of the substrate is not particularly limited and can be appropriately set depending on the location where the substrate is applied. For example, the substrate may have a thickness in the range of 10 to 200 μm, specifically 10 to 150 μm, more specifically 10 to 100 μm.

The first and second metal oxide layers may independently have a refractive index of 1.5 to 2.5, specifically 1.6 to 2.4, more specifically 1.7 to 2.3, for a wavelength of 550 nm. In detail, the refractive index of the first metal oxide layer may be the same as or different from that of the second metal oxide layer.

The metal layer may have a refractive index of 0.1 to 1.5, specifically 0.3 to 1.5, more specifically 0.5 to 1.5, for a wavelength of 550 nm. In addition, the refractive index difference between the first and second metal oxide layers and the metal layer may be in the range of 0.5 to 1.0, specifically 0.5 to 0.8, more specifically 0.5 to 0.75 at 550 nm.

When the metal layer, the first metal oxide layer, and the second metal oxide layer each satisfy the refractive index range, the composite layer has a high light transmittance in the visible region and a low light transmittance in the infrared region, which is useful as an infrared reflective optical film. Can be used.

The refractive indices of the metal layer, the first metal oxide layer and the second metal oxide layer may be controlled by, for example, thickness. Or it can adjust by adjusting the deposition process of each layer. Specifically, the degree of crystallinity may be adjusted by adjusting the deposition conditions of each layer, and thus the refractive index may be different even with the same thickness and material. The deposition process may be performed by a known deposition method, for example, may be performed by a sputtering method. More specifically, the first metal oxide layer and the second metal oxide layer may be deposited by RF sputtering, and the metal layer may be deposited by DC sputtering.

As an example, the thicknesses of the first and second metal oxide layers according to the present invention may be independently 10 to 300 nm, specifically 20 to 200 nm, more specifically 10 to 100 nm. By limiting the thickness of the metal oxide layer to the above range, it is easy to adjust the transmittance or refractive index of light of the metal oxide layer to the above-described range, and it is possible to effectively prevent the absorption of moisture and oxygen into the metal layer, and the metal Deposition of the oxide layer is easy.

In addition, the thickness of the metal layer may be 5 to 30 nm, specifically 8 to 25 nm, and more specifically 10 to 20 nm. When the thickness of the metal layer is in the above range, it is easy to secure visible light transmittance and infrared reflectance.

As another example, the first and second metal oxide layers may independently include antimony (Sb), barium (Ba), gallium (Ga), germanium (Ge), hafnium (Hf), indium (In), and lanthanum. (La), magnesium (Mg), selenium (Se), silicon (Si), tantalum (Ta), titanium (Ti), vanadium (V), yttrium (Y), zinc (Zn), tin (Sn), and zirconium It may include an oxide of one or more metals selected from the group consisting of (Zr).

In addition, the metal layer may include any one or more selected from silver, platinum, gold, copper, chromium, aluminum, palladium, and nickel. Specifically, the metal layer may include silver, platinum or copper, and more specifically, silver. By forming the metal layer as a pure metal as described above, the optical film manufacturing cost can be reduced.

The optical film according to the present invention may further include a hard coating layer formed between the substrate and the first metal oxide layer. Specifically, the hard coating layer is an organic layer or an organic-inorganic hybrid layer formed by UV curing, an organic composition comprising at least one of (meth) acrylate monomers and (meth) acrylate oligomers; Alternatively, the organic composition may be formed by adding inorganic particles such as silica, zirconia, or alumina. The thickness may be 1 to 10 μm, and by forming the hard coating layer as described above, the mechanical strength of the optical film may be increased, and the scratch resistance of the metal layer or the metal oxide layer and the overcoat layer formed thereon may be improved. It can be omitted if necessary.

In addition, the optical film according to the present invention may further include an overcoat layer formed on the second metal oxide layer. Specifically, the overcoating layer is an organic layer or an organic-inorganic hybrid layer formed by ultraviolet curing, and includes an organic composition including at least one of a (meth) acrylate monomer and a (meth) acrylate oligomer; Alternatively, the organic composition may be formed by adding inorganic particles such as silica, zirconia, or alumina. The thickness may be 0.01 to 0.2 μm, and by forming the overcoat layer as described above, it is possible to prevent abrasion or deterioration of the metal oxide layer. It can be omitted if necessary.

Furthermore, the optical film according to the present invention may further include at least one metal layer and a metal oxide layer on the second metal oxide layer. For example, the metal oxide layer and the metal layer may be repeatedly stacked two or more times on the substrate. In addition, a hard coat layer is formed on the substrate, the metal oxide layer and the metal layer are repeatedly stacked two or more times on the hard coat layer, the metal oxide layer is laminated on the last metal layer, the overcoat layer is formed on the metal oxide layer It may be a structure. By including the metal layer and the metal oxide layer of the several layers as described above, there is an advantage that can increase the wavelength selectivity to increase the transmittance of the visible light region and more effectively block only the wavelength of the infrared region.

At least one of the first and second metal oxide layers in the optical film according to the present invention has a density of at least 2.5%, specifically at least 3% or at least 5% of the metal oxide layer formed on a conventionally available window film. Can be increased. More specifically, the density of the first and second metal oxide layers is increased in the range of 5 to 10%.

The optical film according to the present invention may be a window film.

Referring to Figure 1, in one embodiment of the present invention is a laminated structure of an optical film. The first metal oxide layer 21 is formed on the substrate 10, the metal layer 30 is present on one surface of the first metal oxide layer 21, and the second metal oxide layer is formed on the metal layer 30. It is stacked.

Referring to FIG. 2, in an exemplary embodiment of the present invention, a hard coating layer 11 is formed on a substrate 10 and a first metal oxide layer 21 is formed on a hard coating layer 11 in a stack structure of an optical film. The metal layer 30 and the second metal oxide layer 22 are repeatedly stacked, and the overcoat layer 12 is stacked on the second metal oxide layer 22.

In addition, the present invention in one embodiment,

Forming a first metal oxide layer on the substrate;

Forming a metal layer on the first metal oxide layer; And

It provides a method for producing an optical film comprising the step of forming a second metal oxide layer on the metal layer.

In the method for manufacturing an optical film according to the present invention, a metal oxide layer may be formed on a substrate under the conditions of 0.5 to 5 W / cm ² and 0.2 to 10 mTorr using a sputtering method. Specifically, the metal oxide layer may be formed on the substrate at 0.8 to 4.5 W / cm ² and 0.5 to 8.5 mTorr conditions, more specifically at 1.0 to 4.0 W / cm ² and 0.8 to 6 mTorr conditions. Specifically, the first and second metal oxide layers may be formed by an RF sputter method or a DC sputter method, and more specifically, may be formed by a DC sputter method. When deposited under the above conditions, the metal oxide layer having a dense film quality is formed to have excellent moisture permeability and oxygen permeability, thereby preventing discoloration due to oxidation of the metal layer.

In the metal layer forming method, the metal layer may be formed on the metal oxide layer under the conditions of 0.5 to 5 W / cm ² and 0.2 to 10 mTorr using a sputtering method. Specifically, the metal layer may be formed on the metal oxide layer under the conditions of 0.8 to 4.5 W / cm ² and 0.5 to 8.5 mTorr, more specifically 1.0 to 4.0 W / cm ² and 0.8 to 6 mTorr. Specifically, the metal layer may be formed by an RF sputtering method or a DC sputtering method, and more specifically, may be formed by a DC sputtering method. When deposited under the above conditions, the metal layer having a dense film quality is formed to have excellent moisture permeability and oxygen permeability.

Hereinafter, the present invention will be described in more detail with reference to examples according to the present invention, but the scope of the present invention is not limited to the following examples.

The invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

Comparative Example 1

A commercially available window film (optical film) was purchased and used.

Specifically, a first metal oxide layer was formed on the substrate, a metal layer was formed on the first metal oxide layer, and a second metal oxide layer was formed on the metal layer to prepare an optical film.

Comparative Example 2

An optical film was manufactured in the same manner as in Comparative Example 1, except that the density of the first and second metal oxide layers relative to Comparative Example 1 was relatively low.

Example 1.

2 μm of a hard coat layer was formed on the plastic substrate, and ZnO was deposited to a thickness of 30 nm under a condition of 1.5 W / cm ² and 3 mTorr using a DC Sputter method to form a first metal oxide layer. The Ag metal layer was deposited to a thickness of 15 nm on the first metal oxide layer by using a DC sputter method under a condition of 1.5 W / cm ² and 3 mTorr, and 1.5 W / cm ² as the second metal oxide layer on the metal layer. And ZnO was deposited to a thickness of 30 nm under conditions of 3 mTorr. At this time, the deposition was performed by increasing the density of the first and second metal oxide layers compared to Comparative Example 1. Finally, an overcoat layer was formed at 50 nm on the second metal oxide layer to prepare an optical film. An optical film was prepared.

Experimental Example

Water permeability and oxygen permeability measurement experiments were carried out for each optical film prepared in Examples and Comparative Examples. Specifically, the moisture permeability experiment was carried out in accordance with ASTM F-1249 at 38 ℃, 100% RH conditions using the MOCON AUATRANS Model, oxygen permeability experiment 23 ℃ using the MOCON OX-TRANS Model 12/21 10x. , At 0% RH conditions, in accordance with ASTM D-3985. The experimental results are shown in Table 1 below.

Moisture Permeability (mg / m ² day) Oxygen permeability (cc / m ² day) Comparative Example 1 52.1 0.126 Comparative Example 2 400 0.300 Example 1 9 0086

Referring to Table 1, it can be seen that the optical films prepared in Comparative Example 1 and Comparative Example 2 compared with Example 1 has a relatively high moisture permeability and oxygen permeability value. That is, it can be seen that the optical film deposited by increasing the density of the first metal oxide layer and the second metal oxide layer has excellent moisture permeability and oxygen permeability, and is effective in protecting the metal layer from moisture and oxygen.

10: description
11: hard coating layer
12: overcoating layer
21: first metal oxide layer
22: second metal oxide layer
30: metal layer

Claims (13)

A first metal oxide layer, a metal layer, and a second metal oxide layer sequentially formed on the substrate,
Moisture transmittance (WVTR) of the whole optical film is less than 400 mg / m ² day, oxygen transmittance (OTR) is less than 0.3 cc / m ² day is an optical film,
The metal layer comprises one metal selected from silver, platinum and copper,
The metal oxide layer is formed using a sputter method at 0.5 to 5 W / cm ² and 0.2 to 10 mTorr conditions. The method of claim 1,
The refractive index of the first and second metal oxide layers independently ranges from 1.5 to 2.5 at 550 nm. The method of claim 1,
The refractive index of the metal layer is in the range of 0.1 to 1.5 at 550 nm. The method of claim 1,
The refractive index difference between the first and second metal oxide layers and the metal layer is in the range of 0.5 to 1.0 at 550 nm. The method of claim 1,
The thickness of the first and second metal oxide layers is independently in the range of 10 to 300 nm optical film. The method of claim 1,
The thickness of the metal layer is an optical film in the range of 5 to 30 nm. The method of claim 1,
The first and second metal oxide layers independently include antimony (Sb), barium (Ba), gallium (Ga), germanium (Ge), hafnium (Hf), indium (In), lanthanum (La), and magnesium (Mg). ), Selenium (Se), silicon (Si), tantalum (Ta), titanium (Ti), vanadium (V), yttrium (Y), zinc (Zn), tin (Sn) and zirconium (Zr) An optical film comprising an oxide of at least one metal selected. delete The method of claim 1,
An optical film further comprising a hard coat layer formed between the substrate and the first metal oxide layer. The method of claim 1,
An optical film further comprising an overcoat layer formed on the second metal oxide layer. The method of claim 1,
An optical film further comprising at least one metal layer and a metal oxide layer on the second metal oxide layer. The method of claim 1,
The film is an optical film.
It is a manufacturing method of the optical film of Claim 1 containing the 1st metal oxide layer, the metal layer, and the 2nd metal oxide layer sequentially formed on the base material,
Forming a metal oxide layer at 0.5 to 5 W / cm ² and 0.2 to 10 mTorr using a sputter method;
The optical film has a water transmittance (WVTR) of less than 400 mg / m ² day, the oxygen transmittance (OTR) of less than 0.3 cc / m ² day, the method of manufacturing an optical film.

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