JP2018196938A - Laminate film and heat-ray reflective material - Google Patents

Abstract

To obtain a laminate film that can exhibit excellent optical properties and can be formed easily and reliably.SOLUTION: A laminate film according to the present invention has a metal oxide layer, a first silver alloy layer laminated on one surface side of the metal oxide layer, a first silicon layer laminated on one of surfaces of the first silver alloy layer, a first high refractive index layer laminated on one surface side of the first silicon layer, a second silver alloy layer laminated on the other surface side of the metal oxide layer, and a second high refractive index layer laminated on the other surface side of the second silver alloy. It is also possible for the laminate film to further have a second silicon layer interposed between the second silver alloy layer and the second high refractive index layer. It is also possible to obtain a heat-ray reflective material by forming the laminate film on a transparent substrate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated film and a heat ray reflective material.

  Buildings and vehicle windows are required to have a function of blocking visible light and blocking infrared light and ultraviolet light from the viewpoint of energy saving. Specifically, a method of directly applying a coating having such a function to a window or applying the coating to a film and attaching the film to a window is employed.

  For example, Patent Document 1 discloses a visible light transmission provided with a multilayer film including a silver layer having a thickness of 12 to 20 nm, a metal layer having a thickness of 3 nm or more thinner than the silver layer, and two or more transparent oxide layers. A heat ray reflective sheet is disclosed. In Patent Document 1, specifically, a pure Ag layer is used as the silver layer and the metal layer. Patent Document 2 discloses a substrate having a low emissivity coating, and the low emissivity coating includes a first film layer including silicon dioxide formed directly on the substrate, and a transparent dielectric material. A second film layer containing, a third film layer containing an infrared reflective material, and a fourth film layer containing a transparent dielectric material. Specifically, Patent Document 2 discloses pure Ag as the infrared reflecting material. Patent Document 3 discloses a first coating of dielectric material (2), a first functional metal layer (3) made of silver having infrared reflection characteristics, a second coating of dielectric material (5), an infrared At least one sheet with a stack of thin "A" layers composed of a continuous second functional metal layer (6) made of silver and a third coating (8) of dielectric material with reflective properties A glazing assembly comprising a transparent substrate (1) is disclosed. Patent Document 3 discloses pure Ag as the first functional metal layer (3) made of silver and the second functional metal layer (6) made of silver.

  When a pure silver layer is used in a laminated film constituting a heat ray reflective sheet as in Patent Documents 1 to 3, plasma when forming an oxide layer on the pure silver layer, ion irradiation containing oxygen, or a substrate Aggregation occurs in the pure silver layer due to an increase in temperature, and there is a disadvantage that the optical properties of the heat ray reflective film deteriorate.

International Publication No. 2008/065962 Japanese Patent No. 4031760 Japanese Patent No. 4739470

  In view of the above disadvantages, the present inventors have completed the laminated film of the invention according to Japanese Patent Application No. 2006-085828 so that silver can be exhibited without aggregating. As an example of the laminated film of the present invention, a first metal oxide layer (SiOx) that is relatively thicker than the other layers, and a first silver alloy layer (layer) laminated on one surface of the metal oxide layer ( Ag alloy), a second metal oxide layer (SiOx) stacked on one surface of the first silver alloy layer, a first high layer stacked on one surface of the second metal oxide layer. A refractive index layer (TiOx), a second silver alloy layer (Ag alloy) laminated on the other surface of the first metal oxide layer, and a second silver alloy layer laminated on the other surface of the second silver alloy layer. 3 metal oxide layers (SiOx) and a seven-layer structure of a second high refractive index layer (TiOx) laminated on the other surface of the third metal oxide layer.

  Furthermore, the present inventors have conducted intensive studies. As a result, in the simulation, a good transmission spectrum is obtained even in the case of a laminated film having a five-layer structure in which the second metal oxide layer and the third metal oxide layer do not exist. It was found that it can be obtained. However, when a multilayer film having a five-layer structure was fabricated and the transmission spectral was measured, the measurement result was different from the simulation. As a result of further diligent examination by the inventors about this cause, it is found that a part of the atoms of the first high refractive index layer is diffused in the first silver alloy layer, and desired optical characteristics are not obtained by this diffusion. it was thought.

  This invention is made | formed in view of the said situation, The subject of this invention is to obtain the laminated film which can exhibit a favorable optical characteristic, can be formed easily and reliably, and a heat ray reflective material using the same. Objective.

  The present inventors pay attention to suppressing diffusion at the interface between the first silver alloy layer and the first high-refractive index layer, and by providing a silicon layer between the two layers, good optical characteristics can be obtained. It was found that can be obtained.

  That is, the present invention has been made to solve the above-described problems, and a laminated film according to the present invention includes a metal oxide layer and a first silver alloy laminated on one surface side of the metal oxide layer. A first silicon layer laminated on one surface of the first silver alloy layer, a first high refractive index layer laminated on one surface side of the first silicon layer, and the metal oxide A second silver alloy layer laminated on the other surface side of the layer, and a second high refractive index layer laminated on the other surface side of the second silver alloy.

  The laminated film may further include a second silicon layer laminated on the other surface of the second silver alloy layer. The laminated film may further include a third silicon layer laminated on one surface of the second silver alloy layer. The laminated film may further include a fourth silicon layer laminated on the other surface of the first silver alloy layer. Each of the above layers can be formed by a sputtering method.

  The present invention also includes a heat ray reflective material in which any one of the above laminated films is formed on a transparent substrate.

  The laminated film and heat ray reflective material of the present invention can exhibit good optical properties and can be easily and reliably formed.

FIG. 1 is a schematic view showing the structure of one embodiment of the laminated film of the present invention. FIG. 2 is a schematic diagram showing the structure of an embodiment different from FIG. FIG. 3 is a schematic diagram showing the structure of an embodiment different from those in FIGS. 1 and 2. FIG. 4 is a schematic diagram showing the structure of an embodiment different from those shown in FIGS. FIG. 5 is a graph showing the transmission spectrum of Sample A (Example). FIG. 6 is a graph showing the transmission spectrum of Sample B (Example). FIG. 7 is a graph showing the transmission spectrum of Sample C (Comparative Example).

  The laminated film of the embodiment of the present invention is composed of an inorganic material having high visible light transmittance, high heat ray reflectance, and ultraviolet reflectance. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A laminated film 100 in FIG. 1 includes a metal oxide layer 1, a first silver alloy layer 2 laminated on the surface of the metal oxide layer, and a first silicon layer laminated on the surface of the first silver alloy layer 2. 3, the first high refractive index layer 4 laminated on the surface of the first silicon layer 3, the second silver alloy layer 5 laminated on the back surface of the metal oxide layer 1, and the second silver alloy layer 5 A second silicon layer 6 laminated on the back surface of the second silicon layer 6 and a second high refractive index layer 7 laminated on the back surface of the second silicon layer 6.

  That is, in the laminated film 100 of FIG. 1, the first silicon layer 3 is interposed between the first silver alloy layer 2 and the second high refractive index layer 4, and the second silver alloy layer 5 and the second The second silicon layer 6 is interposed between the high refractive index layer 7.

  The laminated film 100 can be formed on a transparent base material such as glass or plastic (shown on the drawing as a visible light transmitting glass substrate) to be a heat ray reflective material. In the embodiment, the terms of the front surface and the back surface are used for ease of understanding, and the substrate side in the laminated film 100 is described as the “back surface”, and the opposite side to the substrate is described as the “surface”. The direction of the back surface is not particularly limited.

  The thickness of the metal oxide layer 1 is preferably greater than or equal to 100 nm and less than or equal to 200 nm, as compared with the other layers constituting the stacked film 100. When the thickness is 100 nm or more, the performance of selectively transmitting visible light can be more effectively exhibited. The thickness is more preferably 110 nm or more, and still more preferably 120 nm or more. On the other hand, if the thickness of the metal oxide layer 1 becomes too thick, the performance of selectively transmitting visible light deteriorates, and the time required for film formation increases, which may deteriorate the productivity of the laminated film. . In addition, since the required time for film formation increases, the temperature of the base material rises, and stress is generated in the film and the base material to cause deflection. Therefore, the thickness of the metal oxide layer 1 is preferably 200 nm or less, more preferably 190 nm or less, and still more preferably 180 nm or less. In particular, the metal oxide layer 1 is preferably silicon oxide and has a thickness of 100 nm to 200 nm.

  Here, the thickness of each layer can be measured by cross-sectional TEM observation. Specifically, for example, an arbitrary 10 points can be imaged using a transmission electron microscope, and the average value of 8 points excluding the minimum value and the maximum value can be set as the layer thickness.

  Silver alloy layers 2 and 5 are laminated on both surfaces of the metal oxide layer 1. In other words, the first silver alloy layer 2 and the second silver alloy layer 5 are interposed via the metal oxide layer 1. Are stacked. The average refractive index of the metal oxide layer 1 at a wavelength of 200 to 1000 nm (hereinafter simply referred to as “average refractive index”) is preferably less than 2.0. The metal oxide layer 1 having an average refractive index of less than 2.0 (hereinafter sometimes referred to as “low refractive index”) has a performance of selectively transmitting visible light in the transmission spectrum of the laminated film 100. The average refractive index of the metal oxide layer 1 is preferably 1.8 or less, more preferably 1.6 or less, and particularly preferably 1.52 or less. Examples of such low refractive index oxides include silicon oxide such as silicon monoxide and silicon dioxide (sometimes expressed as SiOx), aluminum oxide represented by AlOx, aluminum oxynitride represented by AlOxNy, and MgOx. Examples thereof include magnesium oxide, lanthanum oxide represented by LaOx, yttrium oxide represented by YOx, etc., preferably SiOx.

  The silver alloy layers 2 and 5 are comprised from the silver alloy containing a predetermined element, and can suppress aggregation of silver by this. In other words, in a method of forming an oxide layer on pure silver instead of a silver alloy, plasma, oxide irradiation including oxygen, and substrate temperature increase (hereinafter, “ The silver was agglomerated due to the influence of plasma or the like. On the other hand, a silver alloy having Pd (palladium), Nd (neodymium), Cu (copper), Zn (zinc), and Bi (bismuth) as alloy elements can suppress aggregation due to the influence of plasma or the like. In particular, when Cu is used together with Pd or Nd, a high aggregation suppressing effect can be exhibited. Bi may be used singly or by using it together with Nd or Zn, a high aggregation suppressing effect can be exhibited. That is, the first and second silver alloy layers are any of (a) Cu and Pd, (b) Cu and Nd, (c) Bi and Zn, (d) Bi and Nd, and (e) Bi as alloy elements. A silver alloy containing any of these elements is preferable. Such a silver alloy layer of the present invention can exhibit heat ray reflection characteristics more effectively by suppressing aggregation.

  The preferable content of each alloy element is as follows. As for Cu, Nd, and Zn, all are 0.1 atomic% or more. By doing in this way, the silver aggregation inhibitory effect can be exhibited effectively. All of Cu, Nd and Zn are more preferably 0.2 atomic% or more, and further preferably 0.3 atomic% or more. On the other hand, when Cu, Nd, and Zn become excessive, these alloy elements are oxidized by irradiation with ions containing oxygen when forming an oxide layer on the silver alloy layer, and in particular, infrared rays (in this book, heat rays Degrading optical properties such as reflectivity. All of Cu, Nd and Zn are preferably 2.0 atomic percent or less, more preferably 1.5 atomic percent or less, and still more preferably 1.0 atomic percent or less.

  Pd is preferably 0.1 atomic% or more. By doing in this way, the silver aggregation inhibitory effect can be exhibited effectively. Pd is more preferably 0.2 atomic% or more, and further preferably 0.3 atomic% or more. On the other hand, when Pd becomes excessive, the optical constant of the silver alloy layer changes, and the visible light transmittance decreases. Therefore, Pd is preferably 5.0 atomic percent or less, more preferably 4.0 atomic percent or less, and even more preferably 2.0 atomic percent or less.

  Bi is not dispersed in the silver alloy layer, but is concentrated on the surface of the silver alloy layer, and the concentrated layer plays a role of protecting the silver alloy layer. Therefore, Bi is preferably 0.05 atomic% or more, more preferably 0.10 atomic% or more, and further preferably 0.15 atomic% or more. On the other hand, when Bi is excessive, Bi is oxidized by irradiation with ions containing oxygen when forming an oxide layer on the silver alloy layer, and optical characteristics such as infrared reflectivity are deteriorated. Bi is preferably 1.5 atomic percent or less, more preferably 1.2 atomic percent or less, and even more preferably 1.0 atomic percent or less.

  That is, in the case of the above (a), it is a silver alloy containing Cu: 0.1 to 2.0 atomic% and Pd: 0.1 to 5.0 atomic%, and in the case of (b), Cu : A silver alloy containing 0.1 to 2.0 atomic% and Nd: 0.1 to 2.0 atomic%, in the case of (c) above, Bi: 0.05 to 1.5 atomic% and Zn: a silver alloy containing 0.1 to 2.0 atomic%, in the case of (d) above, Bi: 0.05 to 1.5 atomic% and Nd: 0.1 to 2.0 atomic% In the case of (e) above, it is preferable that the silver alloy contains Bi: 0.05 to 1.5 atomic%. In either case, the balance is substantially silver. However, it is naturally allowed to include inevitable impurities brought in depending on the situation of raw materials, materials, manufacturing facilities, and the like.

  The thicknesses of the first silver alloy layer 2 and the second silver alloy layer 5 are preferably 5 nm or more and 15 nm or less. When the silver alloy layer is 5 nm or more, good infrared reflectivity can be realized, and the silver aggregation suppressing effect can be sufficiently exhibited. As for the thickness of a silver alloy layer, 7 nm or more is more preferable, More preferably, it is 8 nm or more. On the other hand, when the thickness of the silver alloy layer becomes too thick, the visible light transmittance is lowered. Therefore, the thickness of the silver alloy layer is preferably 15 nm or less, more preferably 13 nm or less, and still more preferably 12 nm or less.

  The composition and thickness of the first silver alloy layer 2 and the second silver alloy layer 5 may be the same or different, and are preferably the same.

  The laminated film 100 is formed on the front side and the back side of the first laminated body in which the first silver alloy layer 2 and the second silver alloy layer are laminated as described above via the metal oxide layer 1. Each of the refractive index layers 4 and 7 has a laminated structure.

  The average refractive index of the high refractive index layers 4 and 7 is preferably 2.2 or more, more preferably 2.4 or more, and particularly preferably 2.48 or more. The main components of the high refractive index layers 4 and 7 are titanium oxide such as titanium monoxide and titanium dioxide (sometimes referred to as TiOx), niobium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon nitride, and the like. Preferably, it is titanium oxide. The thickness of the high refractive index layers 4 and 7 (the thickness of each layer) is preferably 10 nm or more and 50 nm or less. By setting the thickness within the above range, the ability to selectively transmit visible light can be effectively exhibited. On the other hand, when the thickness exceeds 50 nm, the time required for film formation becomes longer, the productivity of the laminated film is deteriorated, and the time required for the film formation is increased, so that the temperature of the base material rises. Deflection is likely to occur due to stress. The thickness of the high refractive index layers 4 and 7 is more preferably 11 nm or more, and further preferably 12 nm or more. The thickness is more preferably 40 nm or less, and further preferably 30 nm or less. In particular, the high refractive index layers 4 and 7 are preferably titanium oxide and have a thickness of 10 nm to 50 nm.

  The composition and thickness of the first high refractive index layer 4 and the second high refractive index layer 7 may be the same or different, and are preferably the same.

  A first silicon layer 3 is laminated between the first silver alloy layer 2 and the first high refractive index layer 4, and the second silver alloy layer 5 and the second high refractive index layer 7 A second silicon layer 6 is laminated therebetween. That is, the first silicon layer 3 is directly laminated on the surface of the first silver alloy layer 2, and the first silicon layer 3 is laminated directly on the back surface of the first high refractive index layer 4. The second silicon layer 6 is directly laminated on the back surface of the second silver alloy layer 5, and the first silicon layer 6 is laminated directly on the surface of the second high refractive index layer 7. It is in the state.

  The average extinction coefficient of the silicon layers 3 and 6 at a wavelength of 380 to 780 nm is preferably 0.1 or less, more preferably 0.08 or less. The thickness of each of the silicon layers 3 and 6 (the thickness of each layer) is preferably 0.5 nm or more and 5 nm or less. The lower limit of the thickness of the silicon layers 3 and 6 is more preferably 1 nm. On the other hand, the upper limit of the thickness of the silicon layers 3 and 6 is more preferably 4 nm.

  Total of the first silver alloy layer 2 and the second silver alloy layer 5, the first silicon layer 3 and the second silicon layer 6, and the first high refractive index layer 4 and the second high refractive index layer 7 The thickness is preferably 150 nm or more and 500 nm or less. When the total thickness is less than 150 nm, the performance of selectively transmitting visible light tends to deteriorate. If the total thickness is more than 500 nm, the film stress increases, so that film cracking during film formation and peeling from the substrate are likely to occur, and heat rays in which a laminated film is formed on the substrate Film cracking due to temperature changes during use of the reflector and peeling from the substrate are likely to occur. Therefore, the total thickness is preferably 150 nm or more, more preferably 160 nm or more, and further preferably 170 nm or more. The total thickness is preferably 500 nm or less, more preferably 400 nm or less, and still more preferably 300 nm or less.

  The laminated film 100 includes a first silver alloy layer 2 and a second silver alloy layer 5, a first silicon layer 3 and a second silicon layer 6, and a first high refractive index layer 4 and a second high layer. The refractive index layer 7 can be formed by forming a film by sputtering or CVD (Chemical Vapor Deposition), and sputtering is particularly preferable.

<Advantages>
The laminated film 100 is excellent in heat ray reflectivity, and as the heat ray reflectivity, for example, the average reflectance at a wavelength of 780 to 2500 nm can be 75% or more. Moreover, it is excellent in visible light selective transparency and ultraviolet reflection / absorption characteristics. For example, the average transmittance of 380 to 780 nm can be 50% or more, further 60% or more, and the average reflectance of 250 to 380 nm is 50%. As described above, the average absorption rate can be 40% or more. Therefore, the laminated film 100 can be formed on a transparent substrate such as glass or plastic to be a heat ray reflective material.

  Note that the average transmittance of transmitted light having a wavelength of 250 to 310 nm of the laminated film 100 is preferably 0.1% or less. Further, the average transmittance of transmitted light having a wavelength of 380 to 780 nm of the laminated film 100 is preferably 50% or more, and more preferably 60% or more. Furthermore, the average transmittance of transmitted light with a wavelength of 1000 to 1500 nm of the laminated film 100 is preferably 7% or less. Moreover, it is preferable that the average transmittance | permeability of the transmitted light of 1500-2000 nm is 3% or less. Thereby, the laminated film 100 is excellent in visible light selective transparency and ultraviolet reflection / absorption characteristics.

  Further, since the first silicon layer 3 is laminated between the first silver alloy layer 2 and the first high refractive index layer 4, the first silver alloy layer 2 and the first high refractive index are stacked. Diffusion of atoms between the layer 4 and the layer 4 can be accurately suppressed, so that better optical properties can be exhibited. In addition, since the second silicon layer 6 is laminated between the second silver alloy layer 5 and the second high refractive index layer 7, the second silver alloy layer 5 and the second high refractive index are stacked. Diffusion of atoms between the layer 7 and the layer 7 can be accurately suppressed, and thus better optical characteristics can be exhibited. Here, the effect of suppressing the diffusion of atoms by the silicon layers 3 and 6 is suitably exhibited not only at the formation stage of each layer (at the time of sputtering) but also after the formation of the layer (after creation of the laminated film and the heat ray reflective material). The

<Other embodiments>
The present invention is not limited to the configuration of the embodiment described above, and appropriate modifications can be made within a range that can be adapted to the gist of the present invention.

  That is, in the laminated film 100 of FIG. 1, the one having the second silicon layer 6 interposed between the second silver alloy layer 5 and the second high refractive index layer 7 has been described. The present invention is not limited to this, and may be, for example, the laminated film 200 of FIG.

  2 includes a metal oxide layer 11, a first silver alloy layer 12 laminated on the surface of the metal oxide layer 11, and a first silicon laminated on the surface of the first silver alloy layer 12. Of the layer 13, the first high refractive index layer 14 stacked on the surface of the first silicon layer 13, the third silicon layer 18 stacked on the back surface of the metal oxide layer 11, and the third silicon layer 18. A second silver alloy layer 15 laminated on the back surface and a second high refractive index layer 17 laminated on the back surface of the second silver alloy layer 15 are provided. That is, the laminated film 200 of FIG. 2 has the third silicon layer 18 interposed between the metal oxide layer 11 and the second silver alloy layer 15.

  Furthermore, in the present invention, it is also possible to further include a fourth silicon layer interposed between the metal oxide layer and the first silver alloy layer. Specifically, a fourth silicon layer 29 can be laminated between the metal oxide layer 21 and the first silver alloy layer 22 as in the laminated film 300 of FIG. 3 includes a metal oxide layer 21, a fourth silicon layer 29 stacked on the surface of the metal oxide layer 21, and a first silver alloy stacked on the surface of the fourth silicon layer 29. The first silicon layer 23 laminated on the surface of the layer 22, the first silver alloy layer 22, the first high refractive index layer 24 laminated on the surface of the first silicon layer 23, and the metal oxide layer 21. A third silicon layer 28 laminated on the back surface of the second silicon alloy layer 25, a second silver alloy layer 25 laminated on the back surface of the third silicon layer 28, and a second silicon laminated on the back surface of the second silver alloy layer 25. The layer 26 and the second high refractive index layer 27 stacked on the back surface of the second silicon layer 26 are provided.

  In addition, the present invention may further include another metal oxide layer between the high refractive index layer and the silicon layer and / or between the silver alloy layer and the high refractive index layer. Specifically, a first metal oxide layer 41 is stacked between the first high-refractive index layer 34 and the first silicon layer 33 as in the stacked film 400 of FIG. It is also possible to laminate the second metal oxide layer 42 between the silver alloy layer 35 and the second high refractive index layer 37. The laminated film 400 of FIG. 4 is laminated on the surface of the relatively thick metal oxide layer 31, the first silver alloy layer 32 laminated on the surface of the metal oxide layer 31, and the first silver alloy layer 32. The first silicon layer 33, the relatively thin first metal oxide layer 41 stacked on the surface of the first silicon layer 33, and the first high layer stacked on the surface of the first metal oxide layer 41 Refractive index layer 34, third silicon layer 38 stacked on the back surface of metal oxide layer 31, second silver alloy layer 35 stacked on the back surface of third silicon layer 38, and second silver alloy layer 35, a relatively thin second metal oxide layer 42 laminated on the back surface of 35, and a second high refractive index layer 37 laminated on the back surface of the second metal oxide layer 42.

  Here, the average refractive index of the first and second metal oxide layers 41 and 42 is preferably less than 2.0, and may exhibit performance of selectively transmitting visible light. The average refractive index of the first and second metal oxide layers 41 and 42 is more preferably 1.8 or less, still more preferably 1.6 or less, and particularly preferably 1.52 or less. As such a low refractive index oxide, the same oxide as the metal oxide layer 1 described above is preferably used. Thus, by laminating the low refractive index metal oxide layers 31, 41 and 42 and the high refractive index layers 34 and 37 and using two kinds of layers having different refractive indexes, the long wavelength side and the short wavelength side can be obtained due to the interference effect. The light component on the wavelength side can be effectively reflected. The thickness of each of the first and second metal oxide layers 41 and 42 (the thickness of each layer) is not particularly limited, but is preferably 1 nm or more and 20 nm or less. The lower limit of the thickness of the first and second metal oxide layers 41 and 42 is more preferably 3 nm. On the other hand, the upper limit of the thickness of the first and second metal oxide layers 41 and 42 is more preferably 10 nm.

  In the laminated film of the present invention, the number of laminated silver alloy layers, high refractive index layers, and silicon layers can be changed. For example, a multilayer silver film is formed on one or both sides of the metal oxide layer. It is also possible to form an alloy layer and a high refractive index layer. Moreover, it is also possible to interpose another layer between each layer. That is, for example, “a first silver alloy layer laminated on one side of a metal oxide layer” means that the first silver alloy layer is laminated directly on the metal oxide layer without any other layer. And the case where the first silver alloy layer is laminated on the metal oxide layer through another layer. In addition, a film such as a protective layer can be formed on the laminated film by a wet coating method.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited by the following examples, and can of course be implemented with appropriate modifications within a range that can be adapted to the above-described gist. Included in the range.

(Sample A)
A laminated film 400 having the structure shown in FIG. 4 was formed on a transparent substrate using a sputter roll coater “W35-550CS” manufactured by Kobe Steel, Ltd. As a transparent substrate, Toyobo Co., Ltd. Cosmo Shine “A4100” (100 μm thick PET film) was used. The thickness of each layer is as shown in Table 1. Specifically, the first high refractive index layer 34 is a 18.4 nm thick TiO ₂ layer, the first metal oxide layer 41 is a 5.5 nm thick SiO ₂ layer, and the first silicon layer 33 is a first high refractive index layer 34. A silicon layer having a thickness of 1 nm, a silver alloy layer having a thickness of 10 nm as the first silver alloy layer 32, a SiO ₂ layer having a thickness of 149 nm as the metal oxide layer 31, and a silicon layer having a thickness of 3 nm as the third silicon layer 38 The silver alloy layer having a thickness of 10 nm as the second silver alloy layer 35, the SiO ₂ layer having a thickness of 5.1 nm as the second metal oxide layer 42, and the TiO _{2 having a} thickness of 25 nm as the second high refractive index layer 37. A layer was formed. As the first and second silver alloy layers 32 and 35, silver alloy layers containing Pd and Cu as additive elements were used.

(Sample B)
A laminated film of Sample B was formed in the same manner as Sample A, except that the thickness of the first silicon layer 33 was 2 nm.

(Sample C)
A laminated film of Sample C (Comparative Example) was formed in the same manner as Sample A, except that the first silicon layer 33 and the third silicon layer 38 were not laminated.

<Transmission spectrum>
The results of actually measuring the transmission spectra of the laminated films of Samples A to C are shown in FIGS.

  As shown in FIG. 5 and FIG. 6, the laminated films of Samples A and B transmit visible light (wavelength of about 380 to 780 nm) but transmit infrared light (wavelength of about 780 nm or more) and ultraviolet light (about 380 nm or less). It can be seen that the wavelength is not transmitted but reflected or absorbed. In addition, the stacked films of Samples A and B have the first silicon layer 33 and the third silicon layer 38 as compared with the stacked film of Sample C. However, as apparent from the comparison of FIGS. There is little difference in the transmission spectrum. Note that the laminated films of Samples A and B have transmission spectrum characteristics close to results obtained by simulation in the same structure.

<Environmental resistance test>
Table 2 shows the results of performing an environmental resistance test for 48 hours under the conditions of a temperature of 80 ° C. and a humidity of 100% for samples A to C and measuring the visible light transmittance before and after the test.

  As is clear from Table 2, the laminated film of sample C that does not have the first silicon layer 33 and the third silicon layer 38 has a lower total light transmittance after the environmental resistance test, compared to the samples A and In the laminated film of B, the decrease in the total light transmittance was suppressed by the environmental resistance test, but the total light transmittance was rather improved. This is because the first silicon layer 33 and the third silicon layer 38 can suppress the diffusion of atoms in the silver alloy layer even under the environment resistance test, and the decrease in the total light transmittance is suppressed. it is conceivable that.

  Since the present invention can provide a laminated film that can exhibit good optical properties and can be easily and reliably formed as described above, it can be suitably used for, for example, a heat ray reflective material.

1, 11, 21, 31 Metal oxide layers 2, 12, 22, 32 First silver alloy layers 3, 13, 23, 33 First silicon layers 4, 14, 24, 34 First high refractive index layer 5, 15, 25, 35 Second silver alloy layer 6, 26 Second silicon layer 7, 17, 27, 37 Second high refractive index layers 18, 28, 38 Third silicon layer 29 Fourth silicon Layer 41 First metal oxide layer 42 Second metal oxide layer 100, 200, 300 Multilayer film

Claims (6)

Metal oxide layer,
A first silver alloy layer laminated on one side of the metal oxide layer;
A first silicon layer laminated on one surface of the first silver alloy layer;
A first high refractive index layer laminated on one surface side of the first silicon layer;
The laminated film which has the 2nd silver alloy layer laminated | stacked on the other surface side of the said metal oxide layer, and the 2nd high refractive index layer laminated | stacked on the other surface side of the said 2nd silver alloy.   The laminated film according to claim 1, further comprising a second silicon layer laminated on the other surface of the second silver alloy layer.   The laminated film according to claim 1 or 2, further comprising a third silicon layer laminated on one surface of the second silver alloy layer.   4. The laminated film according to claim 1, further comprising a fourth silicon layer laminated on the other surface of the first silver alloy layer. 5.   The laminated film according to any one of claims 1 to 4, wherein each of the layers is formed by a sputtering method.   The heat ray reflective material in which the laminated film of any one of Claims 1-5 was formed on the transparent base material.

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