KR101453471B1 - Light-blocking film - Google Patents

Abstract

Disclosed is a light-shielding film comprising an infrared ray blocking layer formed on an upper portion of a transparent substrate and an adhesive layer formed on the infrared ray blocking layer, wherein a photochromic dye is dispersed in the infrared ray blocking layer.
According to the present invention, visible light can be blocked during the daytime to protect privacy, while sufficient visibility can be ensured when the weather is cloudy or at night.

Description

Light-blocking film < RTI ID = 0.0 >

The present invention relates to a light-shielding film, and more particularly, to a light-shielding film capable of securing visibility at night while shielding visible light when external light is incident.

BACKGROUND ART [0002] Generally, a light-permeable film such as a glass of a vehicle or a building is provided with a colored film for blocking a part of light for protecting privacy, or a method of vacuum depositing a metal component on the surface.

However, according to these methods, a certain amount of visible light is always blocked irrespective of the amount of light, and there is a disadvantage in that the visual field becomes dark at night or on a cloudy day. In particular, have.

In order to solve such a problem, Korean Patent Laid-Open Publication No. 2003-0089544 discloses a photochromic film coated with a photochromic acrylic adhesive, but the photochromic dye does not solve the problem of weak heat and thus does not achieve commercialization have.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a light shielding film capable of securing sufficient visibility at night while blocking visible light during a day using a photochromic material and maintaining the thermal stability of a photochromic dye optimally. do.

The light-shielding film according to an embodiment of the present invention includes an infrared ray blocking layer formed on the transparent substrate and an adhesive layer formed on the infrared ray blocking layer, wherein the photochromic dye is dispersed in the infrared ray blocking layer.

Here, the infrared blocking layer may be alternately laminated with a high refractive index layer and a low refractive index layer, and the photochromic dye may be dispersed in at least one of the high refractive index layer and the low refractive index layer.

Alternatively, the infrared blocking layer may include a first cholesteric layer that reflects incident first polarized light and transmits the second polarized light, and a second cholesteric layer that reflects the second polarized light, The cholesteric layer or the second cholesteric layer.

A light-shielding film according to another embodiment of the present invention includes a photochromic layer formed on a transparent substrate, an infrared blocking layer formed on the photochromic layer, and an adhesive layer formed on the infrared blocking layer.

The light shielding film according to another embodiment of the present invention includes an infrared ray blocking layer formed on one side of a transparent substrate and an adhesive layer formed on the infrared ray blocking layer, wherein the photochromic dye is dispersed in the adhesive layer.

According to the present invention, in the daytime, visible light is blocked to the extent of protecting privacy, while in the case of the weather or nighttime, the external view can be sufficiently secured.

Further, a film of a thin film can be produced by dispersing a photochromic dye in an infrared ray blocking layer.

Further, since the light blocked by infrared rays is incident on the photochromic dye, the problem of thermal instability of the photochromic dye can be solved.

1 is a sectional view of a light-shielding film according to a first embodiment of the present invention,
2 is a modification of the light-shielding film according to the first embodiment of the present invention,
3 is a cross-sectional view of a light-shielding film according to a second embodiment of the present invention,
4 is a modification of the light-shielding film according to the second embodiment of the present invention,
5 is a cross-sectional view of a light-shielding film according to a third 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.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms.

In the present application, the terms "comprises", "having", and the like are used to specify that 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.

Also, the drawings in the present application should be understood as being enlarged or reduced for convenience of description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1, the light-shielding film according to the first embodiment of the present invention includes a transparent substrate 110, an infrared blocking layer 100 formed on the transparent substrate 110, a photochromic dye P on the infrared blocking layer 100, .

The transparent substrate 110 may be glass or a polymer film such as polyethylene terephthalate (PET), polyvinyl alcohol (PVA) and triacetyl cellulose (TAC) or polyimide (PI) There is no restriction on the type of material that can maintain transparency to the extent that it does not disturb the observation.

The infrared ray blocking layer 100 may be formed by alternately stacking the high refractive index layer 120 and the low refractive index layer 130 to reflect light in the infrared wavelength band. In this case, the high refractive index layer material is preferably a polymer resin having a refractive index of 1.6 or more. In addition, a high refractive index inorganic material such as TiO ₂ , ZrO _{2 or} Al ₂ O ₃ is nanopartized and dispersed in a polymer resin to increase the refractive index Applicable.

As the material of the low refractive index layer 130, a refractive index difference of not less than 0.05 with respect to the refractive index of the high refractive index layer 120 may be selected without limitation as long as it is an optically transparent material, but a polymer resin having a refractive index of 1.5 or less is preferable .

When the low refractive index layer 130 has a refractive index of 1.5 or less, the refractive index difference from the high refractive index layer 120 becomes large, so that the number of lamination of the high refractive index layer 120 and the low refractive index layer 130 can be reduced.

The method for implementing alternating layers of the high refractive index layer 120 and the low refractive index layer 130 may be a method of using a coater such as a spin coater, a microgravure coater, a slot die coater, a comma coater, And a method of biaxially stretching a multi-layered polymer resin continuously coated at a predetermined thickness so as to make the thickness of each layer continuously coated so that reflected light can satisfy the reinforcing interference condition can be applied. In addition, various methods of alternately laminating two layers having different refractive indices can be applied.

The photochromic dye (P) dispersed in the infrared blocking layer (100) may include various photochromic dyes known in the art. Photochromism is a change in the color of a chemical that is reversibly denatured by energy, particularly by absorption and blocking of light of a particular wavelength. That is, a photochromic material is changed from a color originally possessed by a specific wavelength of light to another color, and then the light of the applied wavelength is removed or restored to its original color when heat is applied. At this time, light of a specific wavelength may be ultraviolet light.

The photochromic dye (P) may be any of generally known photochromic materials. Specific examples thereof include diarylethene, spiroypran, azobenzene, spirooxazine ), Benzopyran, chromene, and azo compound may be selected from the group consisting of benzopyran, benzopyran, chromene, and azo compound.

In general, the photochromic dye (P) has a blue wavelength region and a green region, and a red region Has a light absorption peak in any one region, or has a light absorption peak in two or more regions. Therefore, in order to absorb light in the entire visible light range by using the photochromic dye (P), it is preferable to mix the dyes having different light absorption peaks.

For example, when absorbing ultraviolet light contained in external light, a first photochromic dye having a light absorption peak in the blue wavelength region, a second photochromic dye having a light absorption peak in the green region, and a second photochromic dye having a light absorption peak Is mixed with the third photochromic dye having the absorption wavelength in the entire visible light region. In this case, there is an advantage that absorption occurs in the entire visible light region and excellent shielding effect can be obtained.

In addition, the color of the light shielding film may be adjusted by using a photochromic dye having an absorption peak at a specific wavelength band according to the user's preference. For example, when a photochromic dye having a light absorption peak in a green region and a red region is used, the color of the light-shielding film may be blue when irradiated with ultraviolet rays, or the color of the light- It can be variously modified.

The photochromic dye (P) according to the present invention is dispersed in the infrared ray blocking layer (100). Specifically, it may be dispersed in only one layer of the high refractive index layer 120 or the low refractive index layer 130 or may be dispersed in all layers.

In addition, the infrared ray blocking layer 100 according to the present invention may be formed of a cholesteric liquid crystal (CLC). Such a cholesteric liquid crystal has a characteristic of reflecting circularly polarized light having a wavelength band which is coincident with the direction of rotation of the liquid crystal and which is similar to the length of the helical pitch.

Therefore, the infrared ray blocking layer 100 includes a first cholesteric layer 120 that reflects incident first polarized light and transmits a second polarized light, and a second cholesteric layer that reflects the second polarized light transmitted through the first cholesteric layer 120 And a second cholesteric layer 130.

For example, the first cholesteric layer 120 is configured to transmit right circularly polarized light (first polarized light) while transmitting left circularly polarized light (second polarized light), and the second cholesteric layer 130 is configured to transmit left circularly polarized light 2 polarized light), so that the light of the infrared wavelength band can be theoretically reflected 100%. At this time, the circularly polarized light reflected by the first cholesteric layer 120 and the second cholesteric layer 130 may be exchanged with each other.

The first and second cholesteric layers 120 and 130 may have a thin film form such as a film and may be applied in various forms.

Specifically, the first and second cholesteric layers 120 and 130 may be formed by polymerization of a cholesteric liquid crystal, a chiral compound, and a curing accelerator. Specifically, cholesteric liquid crystals can be selected from photo-curable nematic liquid crystals composed of long rod-shaped molecules.

Chiral dopant exists in two kinds of right chiral dopant and left chiral dopant and the spiral direction of cholesteric liquid crystal is changed depending on the kind of chiral dopant to be added.

In an embodiment of the present invention, the content of the chiral dopant can be appropriately adjusted in order to reflect light in the infrared wavelength band. Specifically, the length of the helical pitch can be adjusted to about 800 nm to 1200 nm so that the 1.2 cholesteric layer 120 (130) can reflect the infrared wavelength band. If desired, the 1.2 cholesteric layers 120 and 130 may be formed by stacking a plurality of layers having different helix pitch lengths.

At this time, a plurality of first cholesteric layers 120 and second cholesteric layers 130 may be alternately stacked, or a plurality of first cholesteric layers 120 having different helical pitches may be formed first, and a plurality of The second cholesteric layer 130 may be formed.

Also, the first and second cholesteric layers 120 and 130 may be implemented as one cholesteric layer. That is, it can be realized as a cholesteric liquid crystal having a continuously changing pitch from top to bottom so as to selectively reflect different polarized light. Such a configuration can be realized by adjusting the type and concentration of the chiral dopant depending on the thickness direction of the cholesteric liquid crystal.

When the photochromic dye P is dispersed in any one of the first cholesteric layer 120 and the second cholesteric layer 130, the cholesteric layer may contain 90 wt% to 95 wt% %, A chiral compound of 0.3 wt% to 0.9 wt%, and a photochromic dye of 0.05 wt% to 6.0 wt%.

At this time, when the photochromic dye is less than 0.05 wt%, there is a problem that the absorption rate of visible light is low and the light shielding effect is not sufficient. When the photochromic dye exceeds 6.0 wt%, the photochromic dye, There is a problem that the infrared blocking efficiency is deteriorated.

Therefore, when the photochromic dye P is included in each of the first cholesteric layer 120 and the second cholesteric layer 130, the content of the photochromic dye mixed in each layer is reduced, and the orientation of the cholesteric liquid crystal There is an advantage that sufficient shading effect can be maintained while solving the problem that it is not proper.

However, the present invention is not limited thereto, and the photochromic dye P may be included in an adhesive layer (not shown) for bonding the first cholesteric layer 120 and the second cholesteric layer 130 together. In this case, since the photochromic dye (P) has no influence on the orientation of the cholesteric liquid crystal, there is an advantage that the photochromic dye (P) can be sufficiently dispersed. At this time, the photochromic dye (P) can be dispersed in the adhesive resin, and the kind of the adhesive resin is not limited. However, when the photochromic dye is contained in an amount of not less than 8.0 wt% in the entire adhesive resin, there is a problem that the adhesive property of the adhesive resin is lowered. Therefore, the photochromic dye is preferably contained in less than 8.0 wt% in the entire binder resin.

According to the present invention, an adhesive layer 300 and a protective layer 400 are further formed on the infrared ray blocking layer 100. The adhesive layer 300 functions to adhere the light-shielding film such that the light-shielding film can be attached to an optical product such as a car or a building glass or an optical product such as a glass, And serves to protect the adhesive layer 300. Such a protective layer 400 can display a logo of a light-shielding film manufacturer, and a user can easily peel off the protective layer 400 to remove the light-shielding film from a transparent product such as a car or a building glass, And the like. When attaching a shading film to glasses, it can be sunglasses that match the user's eyesight.

At this time, since the light shielding film is attached to the transparent product or the like by the adhesive layer 300, it can be attached to the outer surface of the transparent product (the surface on which the external light is incident directly) or the inner surface according to the user's choice. However, since the photochromic dye (P) is very sensitive to heat, the structure of the light-shielding film may be different depending on the case where the photochromic dye P is adhered to the outer surface of the transparent product or the inner surface thereof so that the thermal stability is maximized.

For example, FIG. 1 shows a structure in which the thermal stability of the photochromic dye can be maximized when the light-shielding film according to the present embodiment is attached to the inner surface of the transparent product. 1, when the external light is incident on the adhesive layer, it is preferable that the photochromic dye P is located on the outermost infrared blocking layer in the incident direction of external light. That is, the infrared ray blocking layer 120 closest to the transparent substrate 110.

With this configuration, when the adhesive layer 300 is attached to the inner surface of the transparent product, external light is absorbed by the photochromic dye P after passing through the infrared ray blocking layer 100, so that the thermal stability can be maximized .

At this time, an ultraviolet blocking layer 200 may be additionally disposed between the infrared ray blocking layer 100 and the transparent substrate 110. When the photochromic dye P dispersed in the infrared ray blocking layer 100 absorbs ultraviolet rays of a predetermined intensity or more, the absorption band of the ultraviolet ray blocking layer 200 changes into the visible light region, It can play a role of blocking. The ultraviolet barrier layer 200 may be formed by alternately laminating a high refractive index layer and a low refractive index layer having different refractive indexes from each other in the same manner as the infrared blocking layer 100, or may be formed of a cholesteric layer.

On the contrary, when the light-shielding film is attached to the outer surface of the transparent article, it is preferable that the photochromic dye P is dispersed in the infrared ray blocking layer 130 located at the outermost position in the incident direction of external light, as shown in FIG. According to this structure, since the external light is absorbed by the photochromic dye P after passing through the transparent substrate 110 and the infrared ray blocking layer 100, the thermal stability can be maximized.

The ultraviolet blocking layer 200 may be formed between the infrared blocking layer 100 and the adhesive layer 300 to block ultraviolet rays that are not absorbed by the photochromic dye.

Since the structure of the light-shielding film is different depending on whether the light-shielding film is attached to the outer surface or the inner surface of the transparent product, it is preferable that the light-shielding film is attached to any surface (outer surface or inner surface) Can be inserted.

3, the light-shielding film according to the second embodiment of the present invention includes a photochromic layer 140 formed on the transparent substrate 110 and an infrared blocking layer 100 formed on the photochromic layer do.

Since the infrared ray blocking layer 100 according to the embodiment of the present invention is the same as that described above, the detailed description will be omitted and the photochromic layer 140 will be mainly described.

The photochromic layer 140 can be produced by mixing a photochromic dye (P) and a binder resin. The photochromic dye (P) is the same as described above. The binder resin may be a known resin composition, but a transparent resin composition is preferably selected, and a transparent acrylic resin may be selected as an example . An infrared ray blocking layer 100, an adhesive layer 300, and a protective layer 400 may be formed on the photochromic layer 140.

At this time, the arrangement of the layers may be different depending on whether the light shielding film is attached to the outer surface or the outer surface of the transparent product as described in the first embodiment. 3, the ultraviolet blocking layer 200, the photochromic layer 140, the infrared blocking layer 100, and the adhesive layer 300 are sequentially stacked on one surface of the transparent substrate 110 The light shielding film attached to the outer surface of the transparent substrate 110 includes an infrared ray blocking layer 100, a photochromic layer 140, an ultraviolet blocking layer 200, and an adhesive layer 300 on the transparent substrate 110, Respectively.

5, the light-shielding film according to the third embodiment of the present invention includes an infrared ray blocking layer 100 formed on a transparent substrate 110, an adhesive layer 300 formed on the infrared ray blocking layer 100, And a protective layer 400 formed on the adhesive layer 300, wherein the photochromic dye P is dispersed in the adhesive layer 300.

The infrared ray blocking layer 100 according to the embodiment of the present invention has already been described above and will not be described in further detail. The photochromic dye P formed in the adhesive layer 300 is contained in an amount of 0.03 wt% to 8.0 wt% with respect to the total adhesive layer composition. When the photochromic dye (P) is contained in an amount of 0.03 wt% or less, the desired absorption rate of visible light can not be attained. If the photochromic dye (P) is contained in an amount of 8.0 wt% or more,

In this case, since the photochromic dye P is included in the adhesive layer 300, the third embodiment of the present invention preferably adheres to the outer surface of the transparent product in order to maintain maximum thermal stability when attached to the transparent product.

Hereinafter, experimental results of a light-shielding film according to an embodiment of the present invention will be described. A light-shielding film formed in the order of a photochromic layer formed on a transparent substrate (PET film), an infrared ray blocking layer and an adhesive layer, wherein the infrared ray blocking layer is a reflection type infrared ray blocking layer using the cholesteric liquid crystal disclosed in the present invention Two types of light-shielding films of absorbing infrared ray blocking layer which are adapted to absorb light of the existing infrared wavelength band were produced.

The two types of shading films were adhered to the inner surface of the glass plate inside the vehicle and incident on the infrared ray blocking layer to the external light and then incident on the photochromic layer. The infrared ray blocking film was irradiated to the sunlight condition of 900,000 lux Lt; / RTI >

In the case of a light-shielding film provided with a reflection-type blocking layer, since the absorption of infrared rays is very small, it is confirmed that the temperature of the light-shielding film itself is prevented from rising and the photochromism in the visible light wavelength band is maintained for 1 hour In the case of a light-shielding film having an absorptive IR blocking layer, the temperature of the light-shielding film itself rises with time, and the photochromic performance gradually deteriorates from the initial 10 minutes, and when 30 minutes have elapsed, And thus the photochromic performance can not be realized .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

100: Infrared blocking layer
110: transparent substrate
120: high refractive index layer, first cholesteric layer
130: low refractive index layer, second cholesteric layer
140: photochromic layer
200: ultraviolet barrier layer
300: adhesive layer
400: protective layer

Claims (18)

An infrared ray blocking layer formed on the transparent substrate;
An adhesive layer formed on the infrared ray blocking layer; And
And a protective layer formed on the adhesive layer,
Wherein the infrared ray blocking layer is formed by alternately stacking a high refractive index layer and a low refractive index layer,
Wherein the photochromic dye is dispersed in an outermost layer in the incident direction of external light among the alternately stacked high refractive index layer and low refractive index layer. The light-shielding film according to claim 1, wherein the photochromic dye is a mixture of a plurality of photochromic dyes having different visible light absorption wavelength bands. delete delete An infrared ray blocking layer formed on the transparent substrate;
A photochromic dye dispersed in the infrared blocking layer;
An adhesive layer formed on the infrared ray blocking layer; And
And a protective layer formed on the adhesive layer,
Wherein the infrared blocking layer includes a first cholesteric layer that reflects incident first polarized light and transmits a second polarized light, and a second cholesteric layer that reflects the second polarized light,
Wherein the photochromic dye is dispersed in the first cholesteric layer or the second cholesteric layer, and the photochromic dye is contained in an amount of 0.05 wt% to 6 wt% of the total composition of the cholesteric layer. The light-shielding film according to claim 5, wherein the first cholesteric layer and the second cholesteric layer are formed of a plurality of layers having different reflection center wavelengths. delete delete The light-shielding film according to claim 1 or 5, further comprising an ultraviolet blocking layer between the transparent substrate and the infrared blocking layer. delete delete delete delete delete delete delete 6. A transparent article with a light-shielding film according to any one of claims 1 to 5. 6. An optical article with a light-shielding film according to any one of claims 1 to 5.

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