KR20170112247A - 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, and includes a first metal oxide layer, a metal layer, and a second metal oxide layer sequentially on a substrate to block water and oxygen penetrating into the metal layer, can do. Specifically, the first and second metal oxide layers may be formed by a specific material and a specific method to control visible light transmittance as well as moisture and oxygen to prevent metal oxidation of the metal layer. In addition, the metal layer can be formed of pure metal, and the manufacturing cost of the optical film can be reduced.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical film and a method of manufacturing the same,

TECHNICAL FIELD The present invention relates to an optical film and a method of manufacturing the same, and more particularly, to an optical film that minimizes defects caused by oxidation of a metal layer.

Among the window films, the solar control film can be divided into absorbing film and reflection film according to the way of blocking infrared rays. Generally, absorption type solar control film is mainly used, and reflection type solar control film is used for high-end products. The reflection type solar control film is a film having a low infrared transmittance by reflecting infrared light, and a structure in which a metal oxide layer and a metal layer are alternately stacked is typical. Specifically, the metal oxide layer has two roles. The first is the role of the index matching layer that controls the visible light transmittance through the adjustment of the refractive index and the thickness. The second is the role of the barrier layer that prevents the oxidation of the metal by blocking water and oxygen.

The metal oxide layer of conventional solar control films has little role as a barrier layer. Therefore, in order to prevent oxidation of the metal layer, an alloy metal having excellent durability is used instead of pure metal. Specifically, APC (Ag-Pd-Cu) is used instead of silver. As a result, the price of the solar control film is increased.

Korean Registered Publication No. 10-1501423

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

According to the present invention,

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

The moisture permeability (WVTR) of the optical film as a whole is independently less than 400 mg / m ² day, and the oxygen permeability (OTR) is less than 0.3 cc / m ² day.

Further, according to the present invention,

Forming a first metal oxide layer on the substrate;

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

And forming a second metal oxide layer on the metal layer.

By forming a metal oxide layer by a specific material and a specific method, not only the visible light transmittance but also moisture and oxygen can be prevented from being oxidized by the present invention.

Specifically, the metal oxide layer functions as a refractive index adjusting layer (index matching layer) and a barrier layer, so that a transparent optical film having excellent durability can be obtained. Unlike the conventional art in which an alloy metal layer is used to produce an optical film having excellent weather resistance, the present invention can produce an optical film having excellent weather resistance even by using a pure metal layer.

In addition, the cost of manufacturing the optical film can be reduced by using pure metal for the metal layer.

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.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, the present invention will be described in detail.

In the 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 film may have a water permeability (WVTR) of less than 400 mg / m ² day and an oxygen permeability (OTR) of less than 0.3 cc / m ² day.

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

The 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 permeability of the optical film may be from 0.0001 to 0.01 cc / m ² day range.

When the moisture transmittance and the oxygen transmittance of the optical film according to the present invention are within the above range, oxidation of the metal layer can be prevented and defects such as discoloration due to oxidation of the metal layer can be minimized.

The optical film according to the present invention may have a transmittance of 60% or more, 65% or more, or 70% or more for light of a wavelength or 550 nm wavelength in a visible light region, for example, about 400 to 700 nm. An optical film satisfying the above 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-mentioned numerical range, but may have a light transmittance of a visible light region, which is usually applicable to a transparent electrode.

Further, the optical film may have a transmittance of 5 to 30%, 20% or less, or 10% or less for light of any wavelength or 780 nm or more in the infrared region, for example, about 800 to 2500 nm. The optical film satisfying the above numerical range can block heat in the infrared region, for example, energy saving is 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 the properties such as light transmittance, water permeability, and oxygen transmittance in the visible light region and / , The material of the first metal oxide layer, the metal layer and the second metal oxide layer, the forming method, the refractive index or the 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 refer to a layer comprising at least about 85 weight percent metal oxide, and the metal layer may refer to a layer comprising at least about 85 weight percent 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, thereby minimizing defects due to oxidation of the metal layer. Specifically, the first and second metal oxide layers can control the visible light transmittance through the adjustment of the refractive index and the thickness, and can prevent the metal of the metal layer from being oxidized by blocking moisture and oxygen.

It is recommended to use materials with good transparency, such as plastic film. Examples thereof include polyester resins such as polyethylene terephthalate resins, polyethylene naphthalate resins and polybutylene terephthalate resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyimide resins, polyolefin resins A film containing at least one selected from resin, (meth) acrylate resin, polyvinyl chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin and polyphenylene sulfide resin can be used have. In particular, a film containing a polyester resin such as a high-strength and low-cost polyethylene terephthalate resin can be used.

The transfer of the substrate is not particularly limited, and can be appropriately set in accordance with the position to which the substrate is applied. For example, the substrate may have a thickness in the range of 10 to 200 占 퐉, specifically 10 to 150 占 퐉, more specifically 10 to 100 占 퐉.

The first and second metal oxide layers may independently have a refractive index for a wavelength of 550 nm of from 1.5 to 2.5, specifically from 1.6 to 2.4, more specifically from 1.7 to 2.3. Specifically, 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. Further, 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 respectively satisfy the above refractive index ranges, the composite layer has a high light transmittance in a visible light region and a low light transmittance in an infrared region, Can be used.

The refractive index of the metal layer, the first metal oxide layer, and the second metal oxide layer can be adjusted, for example, by the thickness. Or by controlling the deposition process of each layer. Specifically, the degree of crystallization can be controlled by controlling the deposition conditions of each layer, so that the refractive index can be different even if the same thickness and material are used. The deposition process may be performed by a known deposition process, for example, by a sputtering process. More specifically, the first metal oxide layer and the second metal oxide layer can be deposited by an RF sputtering method, and the metal layer can be deposited by a DC sputtering method.

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

Further, the thickness of the metal layer may be 5 to 30 nm, specifically 8 to 25 nm, more specifically 10 to 20 nm. When the thickness of the metal layer is within 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 be independently formed of at least one selected from the group consisting of Sb, Ba, Ga, Ge, Hf, (La), magnesium (Mg), selenium (Se), silicon (Si), tantalum (Ta), titanium (Ti), vanadium (V), yttrium (Y), zinc (Zn) (Zr). ≪ / RTI >

The metal layer may include at least one 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 with pure metal as described above, it is possible to reduce the production cost of the optical film.

The optical film according to the present invention may further comprise 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 ultraviolet curing, and comprises at least one of (meth) acrylate monomer and (meth) acrylate oligomer; Or by adding inorganic particles such as silica, zirconia, or alumina to the organic composition. The thickness of the hard coating layer may be 1 to 10 占 퐉. By forming the hard coating layer as described above, the mechanical strength of the optical film is increased and the scratch resistance of the metal layer, the metal oxide layer, and the overcoat layer formed thereon is improved. It can be omitted if necessary.

Further, the optical film according to the present invention may further comprise an overcoat layer formed on the second metal oxide layer. Specifically, the overcoat layer is an organic layer or an organic-inorganic hybrid layer formed by ultraviolet curing, and comprises at least one of a (meth) acrylate monomer and a (meth) acrylate oligomer; Or by adding inorganic particles such as silica, zirconia, or alumina to the organic composition. The thickness may be 0.01 to 0.2 탆. By forming the overcoat layer as described above, abrasion and deterioration of the metal oxide layer can be prevented. 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, it may be a structure in which a metal oxide layer and a metal layer are repeatedly laminated two or more times on a substrate. In addition, a hard coating layer is formed on a substrate, a metal oxide layer and a metal layer are repeatedly laminated on the hard coat layer two or more times, a metal oxide layer is laminated on the last metal layer, and an overcoat layer is formed on the metal oxide layer . ≪ / RTI > By including the metal layer and the metal oxide layer as described above, the wavelength selectivity is increased, thereby increasing the transmittance of the visible light region and blocking the wavelength of the infrared region more effectively.

In the optical film according to the present invention, at least one of the first and second metal oxide layers has a density of not less than 2.5%, specifically not less than 3% or not less than 5%, of the metal oxide layer formed on a commercially available window film Can be increased. And more specifically, the density of the first and second metal oxide layers is relatively increased in the range of 5 to 10%.

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

Referring to FIG. 1, an embodiment of the present invention is a laminated structure of an optical film. A first metal oxide layer 21 is formed on the substrate 10 and a metal layer 30 is present on one surface of the first metal oxide layer 21 and a second metal oxide layer is formed on the metal layer 30 Respectively.

2, a hard coating layer 11 is formed on a substrate 10 with a laminated structure of optical films according to an embodiment of the present invention. A first metal oxide layer 21 is formed on the hard coating layer 11, The metal layer 30 and the second metal oxide layer 22 are repeatedly stacked on the first metal oxide layer 22 and the overcoat layer 12 is laminated 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

And forming a second metal oxide layer on the metal layer.

The method for producing an optical film according to the present invention can form a metal oxide layer on a substrate using a sputtering method under the condition of 0.5 to 5 W / cm ² and 0.2 to 10 mTorr. Specifically, the metal oxide layer may be formed on the substrate at a condition 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 first and second metal oxide layers may be formed by an RF sputtering method or a DC sputtering method, and more specifically, by a DC sputtering method. In the case of depositing under the above-described conditions, a metal oxide layer having a dense film quality is formed to have excellent water permeability and oxygen permeability, thereby preventing discoloration due to oxidation of the metal layer.

The metal layer formation method may use a sputtering method to form a metal layer on the metal oxide layer under the condition of 0.5 to 5 W / cm ² and 0.2 to 10 mTorr. 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, by a DC sputtering method. In the case of depositing under the above conditions, a metal layer having a dense film quality is formed, and water permeability and oxygen permeability are excellent.

Hereinafter, the present invention will be described in more detail with reference to the following Examples. However, the scope of the present invention is not limited by the following Examples.

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

Comparative Example 1

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

Specifically, an optical film was produced by forming a first metal oxide layer on a substrate, forming a metal layer on the first metal oxide layer, and forming a second metal oxide layer on the metal layer.

Comparative Example 2

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

Example 1.

A hard coat layer of 2 탆 was formed on a plastic substrate, and ZnO was deposited thereon to a thickness of 30 nm under DC sputtering conditions of 1.5 W / cm ² and 3 mTorr to form a first metal oxide layer. An Ag metal layer was deposited on the first metal oxide layer to a thickness of 15 nm under a condition of 1.5 W / cm ² and 3 mTorr using a DC sputtering method, and a 1.5 W / cm ² And 3 mTorr of ZnO were deposited to a thickness of 30 nm. At this time, the first and second metal oxide layers were deposited at a higher density than the first comparative example. Finally, an optical film was prepared by forming an overcoat layer of 50 nm on the second metal oxide layer. To prepare an optical film.

Experimental Example

Experiments were conducted to measure the water permeability and the oxygen permeability of each of the optical films prepared in Examples and Comparative Examples. Specifically, the water permeability test was performed according to ASTM F-1249 at 38 ° C and 100% RH using a MOCON AUATRANS Model. The oxygen permeability was measured at 23 ° C. using MOCON OX-TRANS Model 12/21 10x , 0% RH, according to ASTM D-3985. The experimental results are shown in Table 1 below.

Water 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 have relatively high water permeability and oxygen permeability as compared with Example 1. [ 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 water permeability and oxygen permeability and is effective for protecting the metal layer from moisture and oxygen.

10: substrate
11: Hard coating layer
12: overcoat layer
21: First metal oxide layer
22: a second metal oxide layer
30: metal layer

Claims (12)

A first metal oxide layer, a metal layer and a second metal oxide layer sequentially formed on the substrate,
Wherein the optical film has an overall water permeability (WVTR) of less than 400 mg / m ² day and an oxygen permeability (OTR) of less than 0.3 cc / m ² day. The method according to claim 1,
Wherein the refractive indices of the first and second metal oxide layers independently range from 1.5 to 2.5 at 550 nm. The method according to claim 1,
Wherein the refractive index of the metal layer is in the range of 0.1 to 1.5 at 550 nm. The method according to claim 1,
Wherein the difference in refractive index between the first and second metal oxide layers and the metal layer ranges from 0.5 to 1.0 at 550 nm. The method according to claim 1,
Wherein the thickness of the first and second metal oxide layers is independently in the range of 10 to 300 nm. The method according to claim 1,
Wherein the thickness of the metal layer is in the range of 5 to 30 nm. The method according to claim 1,
The first and second metal oxide layers may be independently selected from the group consisting of antimony (Sb), barium, gallium, germanium, hafnium, indium, lanthanum, ), Selenium (Se), silicon (Si), tantalum (Ta), titanium (Ti), vanadium (V), yttrium (Y), zinc (Zn), tin (Sn) and zirconium An optical film comprising an oxide of at least one selected metal. The method according to claim 1,
Wherein the metal layer comprises at least one selected from the group consisting of silver, platinum, gold, copper, chromium, aluminum, palladium and nickel. The method according to claim 1,
And a hard coat layer formed between the substrate and the first metal oxide layer. The method according to claim 1,
And an overcoat layer formed on the second metal oxide layer. The method according to 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 according to claim 1,
Wherein the film is a window film.

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