KR20190023849A - Infrared ray shielding multi-layer film having ultraviolet protection functions - Google Patents

Abstract

According to the present invention, an infrared blocking multi-layered film having an ultraviolet ray blocking function comprises a reflective layer on which first and second resin layers having different refractive indexes are alternately stacked without ultraviolet blocking additives. A refractive index difference between the first resin layer and the second resin layer is 0.15 or more when the first and second resin layers are stacked to 100-200 layers, and the difference is 0.25 or more when the resin layers are stacked under 100 layers, and the difference is 0.12 or more when the layers are stacked over 200 layers. The present invention has a high infrared blocking rate in an infrared ray area wider than the existing area while having a high transmission rate in a visible ray area, and furthermore, the present invention forms a reflecting peak (300-380 nm) of λ/3 for a wavelength (λ) of a central point in a first wavelength of the infrared rays. The present invention may be used as a window film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an infrared ray shielding multi-layer film having ultraviolet ray shielding function,

The present invention relates to an infrared ray blocking multilayer film having an ultraviolet ray blocking function, and more particularly, to a multilayer film comprising a first resin layer and a second resin layer B having different refractive indexes, The refractive index difference between the first resin layer and the second resin layer is 0.15 or more when the first resin layer and the second resin layer are laminated to 100 to 200 layers, , A difference of not less than 0.12 is obtained, which has a high infrared ray blocking rate in a wider infrared region than in the prior art, has a high transmittance in a visible light region, and further has a light transmittance of? / 3 (300 to 380 nm) of ultraviolet rays at the same time.

The films characterized by reflection of light using multi-layer structure have been developed steadily since the 60's, and they have been developed from a simple structure that reflects a specific wavelength to a film that reflects the entire band of visible light, an infrared reflective film, and a reflective polarizing film For packaging, industrial, display, and the like.

As a related art, as disclosed in Japanese Patent Application Laid-open No. 56-99307 and the like, a multilayer film produced by laminating polymers having different refractive indices has been developed steadily since the 60's. Currently, a film that reflects a specific visible ray region, Film for reflection in the visible light region, infrared reflection film, polarized reflection film, packaging, industrial, and display. Such multilayer films utilize light reflection and interference effects that occur in each individual layer, and conventional techniques have shown that the thickness of the individual layers is constantly laminated at a quarter-fold in order to reflect a particular wavelength (?) Into one optical layer A method is used in which a layer is formed by giving a gradient to each layer.

On the other hand, in the case of a conventional window film, it can be manufactured by the same method as above, and an ultraviolet blocking additive is separately used for imparting ultraviolet blocking function (UV-Cut). However, such a functional UV blocking additive has a disadvantage in that it is very expensive even though it is added in a small amount. In addition, when an ultraviolet shielding additive is used, transparency is impaired and an undesirable color tone is developed. There was a limit to increase the yellowness index.

Accordingly, there is a need to provide a functional film capable of simultaneously blocking ultraviolet rays and ultraviolet rays, without using a functional additive for ultraviolet ray blocking function (UV-cut).

Japanese Patent Application Laid-Open No. 56-99307

As a result of efforts made to solve the above problems, the present inventors have found that a reflective layer is formed by alternately laminating a first resin layer and a second resin layer having different refractive indexes, The refractive index difference between the first resin layer and the second resin layer is 0.15 or more when the first resin layer and the second resin layer are laminated to 100 to 200 layers by adjusting the optical thickness and the number of layers, 0.25 or more and 200 layers or more, a difference of 0.12 or more results in a higher infrared blocking rate in a broader infrared region than in the prior art, a higher transmittance in the visible light region, and a higher (300 to 380 nm) of? / 3 with respect to the wavelength? (?), the present inventors have accomplished the present invention.

Accordingly, it is an object of the present invention to provide an infrared ray blocking multilayer film which has a high infrared ray blocking rate in a broader infrared ray region than in the prior art without using an ultraviolet ray blocking additive, has a high transmittance in a visible light region, and can simultaneously block ultraviolet rays.

The object of the present invention is not limited to the above-mentioned object. The object of the present invention will become more apparent from the following description, which will be realized by means of the appended claims and their combinations.

The present invention provides a multilayer reflective film having a reflective layer in which a first resin layer and a second resin layer having different refractive indexes are alternately laminated, wherein a refractive index difference between the first resin layer and the second resin layer is different between the first resin layer and the second resin layer, Is 0.15 or more when laminated with 100 to 200 layers, 0.25 or more when laminated with less than 100 layers, and 0.12 or more when laminated with more than 200 layers. The infrared ray blocking multi- .

The infrared-shielding multilayer reflective film of the present invention is a film having a high infrared transmittance in a broad infrared region, a high transmittance in the visible light region, and a high ultraviolet shielding ability, , It can be used effectively as a window film.

In addition, ultraviolet shielding (300 to 380 nm) can be achieved without using an ultraviolet shielding additive, and the use of the additive can be greatly reduced, so that a unit price advantage can be secured.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all reasonably possible effects in the following description.

1 is a schematic view of an infrared blocking multilayer film according to the present invention.
Fig. 2 shows a cross-section (a) of a conventional window film and a cross-section (b) of a window film to which an infrared-intercepting multilayer film according to the present invention is applied.
3 shows the reflection spectrum results for the films of the comparative example and the example.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown enlarged from the actual for the sake of clarity of the present invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, where a portion such as a layer, film, region, plate, or the like is referred to as being "on" another portion, this includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part such as a layer, film, region, plate or the like is referred to as being "under" another part, it includes not only the case where it is "directly underneath" another part but also another part in the middle.

Hereinafter, the present invention will be described in detail.

The present invention relates to a colored multilayer reflective film comprising a reflective layer in which a first resin layer and a second resin layer having different refractive indices are alternately laminated, and a protective layer for protecting the resin layer.

More specifically, the infrared ray blocking multilayer film has an average reflectance of 50% or more in a wavelength range of 900 to 1200 nm, an average reflectance of 30% or more in a wavelength range of 300 to 380 nm, more preferably 900 to 1200 nm The present invention relates to a multilayered film which simultaneously has an ultraviolet ray blocking function and an infrared ray blocking function with an average reflectance of 70% or more in a wavelength region and an average reflectance of 50% or more in a wavelength region of 300 to 380 nm.

More specifically, the first resin layer may include at least one polymer selected from the group consisting of polyester-based, copolymerized polyester-based, and polynaphthalene.

In addition, the second resin layer may include at least one polymer selected from the group consisting of polymethylacrylate, polystyrene, polyvinyl fluoride, polyvinyl difluoride, and polylactide.

The first resin layer and the second resin layer ensure respective optical thicknesses through drying, melting, extrusion, and stretching of two or more raw materials having a large difference in refractive index. The optical thickness corresponding to each raw material at this time is infrared A thickness corresponding to a wavelength of 800 to 1050 nm is formed. In this case, one or two extruders may be used for extruding the first resin layer, and one extruder may be used for extruding the second resin layer. In order to produce the film of the present invention, To about three compressors may be used, but the present invention is not limited thereto. In addition, although the stretching method was also used for biaxial stretching, simultaneous biaxial stretching can also be produced.

The film of the present invention can be designed to be able to block ultraviolet rays by forming a reflection peak of? / 3 (300 to 380 nm) with respect to the wavelength? Of the center point of the wavelength of infrared rays.

[Equation 1]

F-ratio = n ₂ d ₂ / (n ₁ d ₁ + n ₂ d ₂ )

In the equation (1), n ₁ is the refractive index of the first resin layer, n ₂ is the refractive index of the second resin layer, d ₁ is the thickness of the first resin layer, and d ₂ is the thickness of the second resin layer, n _1> n _2, and the F-ratio value, but values are reflection peaks of λ / 2 for the wavelength (λ) of the center point of the infrared wavelength it occurs when from 0.5, the F-ratio value is greater than or equal to 0.5 or When it is formed to be 0.5 or less, a reflection peak of? / 2 is produced. Therefore, a film having a visible light transmittance can be prepared by adjusting the F-ratio value.

The present invention provides a functional film having a high infrared transmittance in a broad infrared region and a high transmittance in a visible light region and capable of blocking ultraviolet rays by controlling the thickness and the number of layers of the resin layer without using an ultraviolet shielding additive . FIG. 2 shows a cross-section (a) of a conventional window film and a cross-section (b) of a window film to which an infrared shielding multilayer film according to the present invention is applied. In the case of using the infrared shielding multilayer film according to the present invention, It is not necessary.

For this, the thickness of the first resin layer is preferably 130 to 200 nm, the thickness of the second resin layer is preferably 150 to 250 nm, more preferably the thickness of the first resin layer is 130 to 180 nm, Is 150 to 220 nm. In addition, each of the resin layers does not have the first resin layer and the second resin layer having the same thickness alternately stacked but laminated with a thickness gradient with respect to the number of layers stacked.

In one embodiment of the present invention, a first resin layer comprising ethylene terephthalate (PET) having a thickness in the range of 135 to 166 nm is formed as a 93 layer and a second resin layer containing polymethylacrylate (PMMA) in the range of 150 to 160 nm When reflecting layers having a total of 187 layers with 94 resin layers are laminated, the thickness of the reflective layer is increased by Δdx 1 / the number of laminated layers at the initial thickness every time the resin layers are laminated alternately . At this time, Δd is the thickness difference.

More specifically, in this embodiment, Δd (difference in thickness) of the first resin layer is 166-135 = 31, and the thickness of 1/93 (31 X 1/93 = about 0.33 nm ) Is increased. In other words, when the first resin layer having a thickness of 135 nm is first laminated, the second resin layer is laminated first, then the first resin layer having a thickness of 135.33 nm is laminated, and when the second resin layer is laminated, nm thick first resin layer is laminated in this manner until the first resin layer having a thickness of 166 nm is stacked. This is also the case for the second numerical layer.

In addition, the first resin layer and the second resin layer are preferably 160 to 200 layers, and more preferably 170 to 180 layers. At this time, the reflective layer alternately stacked with the first resin layer and the first resin layer is formed to have a total thickness in the range of 30 to 40 mu m. Preferably 30 to 35 mu m.

The refractive index difference between the first resin layer and the second resin layer is 0.15 or more when the first resin layer and the second resin layer are laminated to 100 to 200 layers, and when the laminate is less than 100 layers, When laminated over 200 layers, a difference of 0.12 or more occurs. By forming a reflection peak of? / 3 (300 to 380 nm) with respect to the wavelength? Of the central point of the wavelength of infrared rays, ultraviolet ray blocking becomes possible.

In addition, the infrared blocking multilayer film includes a protective layer including polyethylene terephthalate (PET) on one side or both sides of the reflective layer. At this time, the protective layer may include polyethylene terephthalate (PET), and the average thickness thereof is 2 to 5 占 퐉. Preferably 2 to 4 mu m.

The infrared ray blocking multilayer film of the present invention thus produced has a high infrared transmittance in a broad infrared region, has a high transmittance in the visible region, and can simultaneously shield against ultraviolet rays. It is equivalent in terms of physical properties and can be usefully used as a window film.

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

Example  1-4

A protective layer comprising polyethylene terephthalate (PET) was laminated on both sides of a reflective layer by laminating a first resin layer and a second resin layer alternately with the raw materials and conditions shown in Table 1 below, To produce the indicated infrared blocking multilayer film.

Comparative Example  One

An infrared blocking multilayer film was prepared in the same manner as in Example 1. Comparative Example 1 is a film used as a conventional window film.

Comparative Example  2

An infrared blocking multilayer film was prepared in the same manner as in Example 1, and Comparative Example 2 was also used as a conventional window film.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 The first resin layer (refractive index) PET (1.662) PET (1.662) PET (1.662) PET (1.662) PET (1.662) PET (1.662) The second resin layer (refractive index) PMMA (1.492) PMMA (1.492) PMMA (1.492) PMMA (1.492) PMMA (1.492) PMMA (1.492) F-ratio 0.5 0.55 0.5 0.5 0.55 0.55 Reflection wavelength 950 nm 950 nm 900 to 1100 nm 975 to 1175 nm 850-1050 nm 825-1025 nm Single layer
thickness The first resin layer PET (143 nm) PET (128 nm) PET
(135 to 166 nm) PET
(146.5-178 nm) PET
(127 to 158 nm) PET
(124 to 154 nm) The second resin layer PMMA (159 nm) PMMA (174 nm) PMMA (150 to 160 nm) PMMA (163 to 197 nm) PMMA
(174 to 215 nm) PMMA
(183 to 210 nm) Whether the thickness of the layer is gradient Equal thickness Equal thickness Thickness gradient Thickness gradient Thickness gradient Thickness gradient Difference in refractive index 1.662-1.492 1.662-1.492 Same as left Same as left Same as left Same as left Number of layers 143th floor 143th floor 187th floor 187th floor 187th floor 187th floor Thickness configuration
(Protective layer-reflective layer-protective layer) 8.2-21.6-8.2 8.2- 21.6-8.2 3.2-30.6-3.2 2.5-32.9-2.5 2.8-32.6-2.7 3.0-32.1-2.9

Experimental Example : Physical property measurement test

(1) Measurement of infrared blocking rate

The infrared shielding multilayer film produced in Examples 1 to 4 and Comparative Examples 1 and 2 was cut into 10 cm wide and 10 cm long, and the foreign substances adhered to the film surface were removed. Equipment: Abbe refractometer, manufactured by ATAGO, Model: 4T1240 To measure an ultraviolet cut (IRC) in the range of 900 to 1000 nm, the range of 9000 to 1100 nm, and the range of 9000 to 1200 nm.

(2) Measurement of visible light transmittance

After cutting the infrared blocking multilayer film produced in Examples 1 to 4 and Comparative Examples 1 and 2, the foreign substances on the surface of the film were removed, and visible light transmission (VLT) in the region of 380 to 780 nm was measured Respectively.

(3) Measurement of UV blocking rate

After the infrared blocking multilayer films prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were cut, the foreign matter adhering to the surface of the film was irradiated with ultraviolet ray (UV) rays in the range of 300 to 340 nm and 350 to 390 nm Respectively.

The measurement results of the multilayered films of Examples and Comparative Examples are summarized in FIG. 3 and Table 2 below.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 UVC (300 to 340 nm) 39.7 34.8 77.7 32.5 54.9 46.5 UVC (350 to 390 nm) 6.5 8.9 88.7 92.9 85.5 84.1 VLT (380-780 nm) 91.0 87.7 87.2 81.6 78.6 77.7 IRC (900 to 1000 nm) 76.9 80.7 97.2 59.0 76.4 71.3 IRC (900 to 1100 nm) 46.8 47.9 98.0 78.1 86.7 84.6 IRC (900-1200 nm) 35.3 35.5 92.2 84.9 90.6 88.3

As shown in Table 2, when the first resin layer and the second resin layer are laminated with 100 to 200 layers, the refractive index difference between the first resin layer and the second resin layer is 0.15 or more, Ultraviolet light intensity ratio was excellent. Specifically, the films prepared in Examples 1 to 4 exhibited an average reflectance of 50% or more, preferably 80% or more, more preferably 90% or more, in an infrared wavelength range of 900 to 1200 nm. Also, the average reflectance was improved by 30% or more, preferably by 50% or more, more preferably by 80% or more in the ultraviolet wavelength range of 300 to 380 nm.

3 is a measurement result of the reflection spectrum. 3, the films prepared in Examples 1 to 4 had a high infrared ray blocking rate in a wide infrared region and a comparable degree of transmittance in a visible region in comparison with Comparative Examples 1 and 2, which are conventional films. (300 to 380 nm) with respect to the wavelength (?) Of the central point of the wavelength of the infrared ray, it was confirmed that ultraviolet ray blocking is possible.

As a result, it has been confirmed that the infrared multi-layer film of the present invention is excellent in infrared ray and ultraviolet ray shielding effect, and can be effectively applied to window films and security films.

Claims (9)

A multilayer reflective film having a reflective layer in which first and second resin layers having different refractive indexes are alternately stacked, characterized in that a refractive index difference between the first resin layer and the second resin layer is in the range of 100 - Wherein the laminated film has a thickness of 0.15 or more when laminated with 200 layers, and 0.25 or more when laminated with less than 100 layers, and 0.12 or more when laminated with layers exceeding 200 layers.
The method according to claim 1, wherein the first resin layer comprises at least one polymer selected from the group consisting of polyester based, copolymerized polyester based, and polynaphthalene,
Wherein the second resin layer comprises at least one polymer selected from the group consisting of polymethylacrylate, polystyrene, polyvinyl fluoride, polyvinyl difluoride, and polylactide. Infrared blocking multilayer film.
The method of claim 1, wherein the thickness of the first resin layer is in the range of 130 to 200 nm, and the thickness of the second resin layer is in the range of 150 to 250 nm. Infrared shielding multilayer film with blocking function.
The infrared blocking multilayer film according to claim 1, wherein the first resin layer and the second resin layer have a lamination number of 160 to 200 layers.
The infrared ray blocking multi-layer film according to claim 1, wherein the total thickness of the reflective layer alternately laminated to the first resin layer and the first resin layer is 30 to 40 占 퐉.
The infrared-shielding multilayer film according to claim 1, wherein the infrared-shielding multilayer film comprises a protective layer containing polyethylene terephthalate (PET) on one side or both sides of the reflective layer.
7. The infrared blocking multilayer film according to claim 6, wherein the protective layer has an average thickness of 2 to 5 占 퐉.
The infrared shielding multilayer film according to claim 1, wherein the infrared blocking multilayer film has an ultraviolet shielding function with an average reflectance of 50% or more in a wavelength range of 900 to 1200 nm and an average reflectance of 30% or more in a wavelength range of 300 to 380 nm.
The infrared blocking multilayer film according to claim 1, wherein the infrared blocking multilayer film has an ultraviolet blocking function with an average reflectance of 70% or more in a wavelength range of 900 to 1200 nm and an average reflectance of 50% or more in a wavelength range of 300 to 380 nm.

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