JP5144302B2 - Reflective film laminate - Google Patents

Description

  The present invention belongs to a technical field related to a reflective film laminate, and particularly relates to a technical field related to a reflective film laminate used for lighting fixtures, automobile headlamps, and the like.

  Since the Ag thin film has a very high reflectance of visible light when the film thickness is about 70 nm, it has been conventionally used for applications such as reflectors for lighting fixtures and optical mirrors such as liquid crystal displays.

  However, Ag has a problem in that it easily aggregates and the reflectivity decreases due to aggregation. This agglomeration occurs when halogen ions in the atmosphere are adsorbed on the Ag surface together with moisture. Therefore, the Ag surface is coated with a resin to block the environment. Since aggregation occurs due to the intrusion of ions, innumerable white spots and discoloration occur on the surface of the substrate on which the Ag film is formed, which is a cause of deterioration in design and commercial properties.

  In addition to the above-mentioned aggregation problem, the reflective film is exposed to a high temperature of about 80 to 200 ° C. by the lamp, so that sulfur in the atmosphere diffuses in the resin film and reacts with the Ag reflective film to react with the surface. As a result of the sulfidation of the steel, it gradually turns black and this causes a problem in that the reflectance decreases.

Since Ag is also used as an electric contact material and a decorative film, improvement of sulfidation resistance has been attempted in this field by alloying or multilayering. For example, it is attempted to prevent the deterioration of the Ag film by forming a UV curable resin, an acrylic resin, or a ceramic protective film on the Ag thin film (Japanese Patent Laid-Open Nos. 2000-106017 and 2006-98856). reference). However, when it is exposed to high temperatures such as reflective films for lighting fixtures and automobile headlamps, even if the above-mentioned means for improving sulfidation resistance is applied, the sulfidation resistance is insufficient. The thin film is sulfided and the reflectivity is lowered.
JP 2000-106017 A JP 2006-98856 JP

  The present invention has been made in view of such circumstances, and an object thereof is to provide a reflective film laminate in which Ag aggregation and sulfidation are unlikely to occur.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. According to the present invention, the above object can be achieved.

  The present invention thus completed and capable of achieving the above object relates to a reflective film laminate, and is a reflective film laminate according to claims 1 to 5 (reflective film laminate according to the first to fifth inventions). It has the following configuration.

That is, the reflective film laminate according to claim 1 is a reflective film laminate used on a substrate used in a luminaire or an automobile headlamp, wherein Ag is a main component and Bi is 0.08 to 2.0 on the substrate. A first layer made of an Ag alloy containing at least 0.1 to 3.0 at% of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta , and W in total is formed, and is formed thereon. A reflective film laminate in which a second layer made of one or more metal oxides of Si, Al, and Ti is formed [first invention].

  The reflective film laminate according to claim 2 is the reflective film laminate according to claim 1, wherein the first layer has a thickness of 200 nm or more [second invention].

  The reflective film laminate according to claim 3 is the reflective film laminate according to claim 1 or 2, wherein the thickness of the second layer is 2 to 50 nm [third invention].

  The reflective film laminate according to claim 4, wherein the Ag alloy contains at least one of Au, Pt, Pd, and Rh in a total amount of 0.3 to 5 atomic%. It is a body [fourth invention].

  The reflective film laminate according to claim 5 has a visible light reflectance of 90% or more measured by light having a wavelength range of 380 to 780 nm with a D65 light source in accordance with JIS R3106. [5th invention]. The reflective film laminate according to claim 6 is the reflective film laminate according to any one of claims 1 to 5, wherein a plasma polymerization film is formed on the second layer [Sixth Invention].

  In the reflective film laminate according to the present invention, Ag aggregation and sulfidation are unlikely to occur, and therefore the durability is improved.

  In order to suppress the reaction with sulfur compounds and halogen elements, it is necessary to form a protective film for shielding the environment from the Ag alloy film, but since it is used as a reflective film, the protective film must be colorless and transparent. I must. Examples of the colorless and transparent protective film include oxide films such as silica, alumina, and titania. However, even if these colorless and transparent protective films are simply formed on an Ag or Ag alloy thin film, the formation of pinholes cannot be avoided. When the sulfidation test is performed in contact with hydrogen sulfide gas, an infinite number of brown, dotted sulfidation occurs.

  Therefore, the present inventors have intensively studied, and as a result, by controlling the composition of the Ag alloy and the thickness of the film, the pinholes of the protective film formed thereon can be reduced, and the sulfide resistance and heat resistance are reduced. The inventors have found that the moisture resistance can be improved, and have completed the present invention based on this finding.

  The thus completed reflective film laminate according to the present invention contains, on the substrate, Ag as a main component and Bi in an amount of 0.1 to 2.0 atomic%, and Ti, V, Cr, Zr, Nb, Mo, Hf, A first layer (first layer) made of an Ag alloy containing a total of 0.1 to 3.0 atomic% of one or more of Ta, W, Ge, and Zn is formed, and one or more of Si, Al, and Ti are formed thereon. A second layer (second layer) made of a metal oxide is formed.

  In the reflective film laminate according to the present invention, the Ag alloy forming the first layer contains 0.08 to 2.0 atomic% of Bi, and Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Co , Ge, and Zn (hereinafter also referred to as “A”) in a total amount of 0.1 to 3.0 atomic%.

  Bi has an effect of suppressing the growth of Ag crystal grains and Ag aggregation due to heat at a content of 0.08 atomic% or more. That is, heat resistance is improved and Ag aggregation is less likely to occur. That is, the aggregation resistance is improved. For this reason, Bi content needs to be 0.08 atomic% or more. Although depending on the temperature at which the reflective film laminate is exposed, it is preferably at least 0.1 atomic%, more preferably at least 0.15 atomic%. However, when Bi is added in an amount larger than 2.0 atomic%, the effect is saturated, but the overall reflectivity is lowered, particularly the reflectivity of visible light at a low wavelength is lowered, and the Ag film becomes yellow. This is not preferable in terms of color. For this reason, the Bi content needs to be 2.0 atomic% or less. Preferably it is 1.5 atomic% or less, More preferably, it is 1.0 atomic% or less. From the above points, the Bi content in the Ag alloy of the first layer according to the present invention is set to 0.08 to 2.0 atomic%.

  By containing A (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Co, Ge, Zn) in a total of 0.1 to 3.0 atomic% together with Bi, sulfidation is unlikely to occur. Become. That is, the sulfidation resistance is improved. Among A, V, Cr, Mo, W, Ge, and Zn improve the sulfidation resistance. If the total content of A (hereinafter also referred to as A content) is less than 0.1 atomic%, the effect of improving sulfidation cannot be obtained. For this reason, the content of A needs to be 0.1 atomic% or more. Preferably it is 0.2 atomic% or more, more preferably 0.3 atomic% or more. On the other hand, when it is added in an amount larger than 3.0 atomic%, the reflectance is lowered. For this reason, the content of A needs to be 3.0 atomic% or less. Preferably it is 2.5 atomic% or less, More preferably, it is 2.0 atomic% or less. From the above points, the content of A in the first-layer Ag alloy according to the present invention is set to 0.1 to 3.0 atomic%. Since the influence of the element content on the reflectivity differs depending on the elements in A, the upper limit of the A content is measured by light in the wavelength range 380 to 780 nm with a D65 light source in accordance with JIS R3106. It is desirable to adjust the visible light reflectivity appropriately to be 90% or more.

  In the reflective film laminate according to the present invention, the second layer formed on the first layer is made of one or more metal oxides of Si, Al, and Ti.

The second layer acts as a protective film for shielding the first layer (Ag alloy film) and the environment, but must be colorless and transparent. As the transparent oxide film, there is an oxide film made of SnO ₂ , ZnO, etc. in addition to an oxide film made of one or more metal oxides of Si, Al, Ti, etc., but an oxide film made of SnO ₂ , ZnO ₂ , etc. Since each of them has a color such as yellow, the light color of the light source cannot be reproduced. An oxide film made of one or more metal oxides of Si, Al, and Ti is colorless and transparent. From the above points, the second layer according to the present invention is made of one or more metal oxides of Si, Al, and Ti. The metal oxide of the second layer is not limited to any one of Si, Al, and Ti, and may be a composite oxide of two or more of Si, Al, and Ti.

  In the reflective film laminate according to the present invention, the thickness of the first layer (Ag alloy film) is preferably 200 nm or more [second invention]. The reason for this will be described below. When the thickness of the Ag alloy film is about 70 nm, the reflectance of visible light becomes very high, so that the reflection performance is good. Even when the Ag alloy film is as thin as 200 nm or less, the second layer metal oxide film (protective film) can suppress sulfurization to some extent. That is, even when a sulfidation test is performed in which hydrogen sulfide gas that has been evaporated by exposure above a 5% ammonium sulfide aqueous solution is contacted, sulfidation can be suppressed to some extent. However, when the surface subjected to the sulfidation test is observed with an optical microscope at a magnification of 100 to 200 times, it is confirmed that the sulfidized portion is innumerable as brown spots, and the sulfidation resistance is perfect. I can't say that. When the thickness of the first layer (Ag alloy film) is 200 nm or more, brown spot-like sulfurization is not observed even after the above-mentioned sulfurization test. Therefore, the thickness of the first layer (Ag alloy film) is preferably 200 nm or more. Furthermore, it is preferably 230 nm or more, and more preferably 250 nm or more.

  The upper limit of the thickness of the first layer (Ag alloy film) is not particularly defined, but is preferably 500 nm from the viewpoint of material cost.

The thickness of the second layer (metal oxide film) is preferably 2 to 50 nm [third invention]. The reason for this will be described below. When the thickness of the second layer is less than 2 nm, there are too many pinholes and it is difficult to stop sulfidation. In this respect, the thickness of the second layer is preferably 2 nm or more. More preferably, it is 5 nm or more. On the other hand, if it exceeds 50 nm, the film stress increases, and cracking and peeling occur in the constant temperature and humidity test. SiO ₂ and Al ₂ O ₃ are colorless and transparent visually, but have a light absorption region in the vicinity of 300 nm to 350 nm. If the thickness exceeds 50 nm, the absorption of light in this wavelength region increases, and it is visually undesirable and yellowish. From these points, the film thickness of the second layer is preferably 50 nm or less. More preferably, it is 40 nm or less, More preferably, it is 35 nm or less. From the above points, the thickness of the second layer is preferably 2 to 50 nm.

  As described above, the Ag alloy of the first layer preferably contains Bi and A and contains at least one of Au, Pt, Pd, and Rh in a total amount of 0.1 to 5 atomic% [fourth invention]. This is because the chemical stability can be further improved by adding one or more of Au, Pt, Pd, and Rh. If the total content of these elements is less than 0.1 atomic%, the chemical stability improvement effect is small, and if it exceeds 5 atomic%, the cost of the Ag alloy film increases and the initial reflectance tends to decrease. There is. Therefore, the total content of these elements is preferably 0.1 to 5 atomic%. More preferably, it is 0.3-3 atomic%.

  In the reflective film laminate according to the present invention, a plasma polymerization film may be laminated in a thickness range of 10 to 1000 nm on the second layer (metal oxide film) in order to enhance durability. At this time, the plasma polymerized film is preferably formed using organic silicon as a raw material. Examples of the organic silicon include hexamethyldisiloxane, hexamethyldisilazane, and triethoxysilane. Since the plasma polymerized film formed from organic silicon as a raw material has very poor wettability with water, it is possible to prevent intrusion of moisture and halogen ions. Moreover, since the plasma polymerized film is excellent in acid resistance and alkali resistance, it has an effect of maintaining the characteristics of the reflective film laminate in both an acidic atmosphere and an alkaline atmosphere.

  A commonly used material for the reflective film is Al, and its reflectance is approximately 85%. On the other hand, the reflectance of the reflective film laminate according to the present invention is high, and the visible light reflectance measured by light having a wavelength range of 380 to 780 nm with a D65 light source in accordance with JIS R3106 is 90% or more. It is desirable to do so. Such a reflective film can obtain the same brightness even if the power consumption of the light source (lamp) is lower than before, or can reduce the number of lamps when using a plurality of lamps. Therefore, the cost of the light source can be reduced. In addition, it can be suitably used as a reflector for an LED light source, for which sufficient brightness could not be secured with conventional reflective film materials.

  In the reflective film laminate according to the present invention, a substrate made of glass, resin, or the like can be used. These may be selected and used according to the temperature of heat generated by the light source. For example, it is preferable to use glass when the temperature is about 180 ° C. or higher, PET-PBT material when the temperature is 120 to 180 ° C., and polycarbonate material when the temperature is 120 ° C. or lower. In addition, it is recommended to form an Ag alloy of the first layer of the reflective film laminate according to the present invention using a sputtering method using an alloy sputtering target.

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to this embodiment, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. include.

[Example 1]
A pure Ag or Ag-Bi alloy target (target made of pure Ag or a target made of Ag-Bi alloy) of φ100mm x t5mm is set in the chamber of the sputtering apparatus as shown in Fig. 1, and a PC substrate of φ50mm x t1mm ( A substrate made of polycarbonate) was set so as to face the target, and the inside of the chamber was evacuated to 1 × 10 ⁻⁵ torr or less. After that, Ar gas is introduced into the chamber so that the pressure in the chamber becomes 2 × 10 ⁻³ Torr, DC is applied to the target to generate plasma, and the target is sputtered with a DC power of 100 W. Thus, an Ag thin film or an Ag alloy thin film (first layer) was formed on the PC substrate. At this time, as the target, a pure Ag target was used in the case of forming an Ag thin film. In the case of forming an Ag alloy thin film not containing Bi, the film was formed using various metal chips placed on a pure Ag target. In the case of an Ag alloy thin film containing elements other than Bi and Bi, films were formed using various metal tips placed on an Ag-Bi alloy target. The distance between the target and the PC substrate was 80 mm, and the film was formed while rotating the PC substrate. The addition amounts of various additive elements in the Ag alloy thin film thus formed were determined by measurement by ICP mass spectrometry.

Then, replace the target SiO ₂ target (target made of SiO _2), was evacuated to the interior of the chamber becomes less 1 × 10 ^-5 Torr. After that, Ar gas is introduced into the chamber, the plasma pressure is generated by applying RF (radio frequency) current to the target so that the pressure in the chamber becomes 2 × 10 ⁻³ Torr, and SiO ₂ with an RF power of 200 W. By sputtering the target, a SiO ₂ film (second layer) was formed on the first layer (Ag thin film or Ag alloy thin film) to obtain a reflective film laminate. The distance between the target and the PC substrate was 80 mm, and the SiO ₂ film was formed while rotating the substrate.

  Table 1 shows the composition and film thickness of the first layer and the composition and film thickness of the second layer in the thus obtained reflective film laminate. For these reflective film laminates, the visible light reflectivity (initial reflectivity) is measured with light in the wavelength range of 380 to 780 nm with a D65 light source in accordance with JIS R3106, and then the sulfur resistance is maintained under the following conditions: Tests and heat resistance tests were performed.

[Sulfurization resistance test]
・ Test solution composition: 5% ammonium sulfide aqueous solution ・ Exposure position: Installed so that the film formation surface faces the liquid surface at a height of 3 cm from the test solution surface ・ Exposure time: 20 minutes

[Heat resistance test]
・ Test temperature: 120 ℃
・ Test time: 1000 hours

  For the reflective film stack after the above sulfidation resistance test, the surface (surface exposed in the sulfidation resistance test) was magnified 200 times with an optical microscope, a photo of the surface was taken, and the microscopic image taken at the same magnification The sulfidation points generated in the 0.2 mm x 0.2 mm area (that is, the actual size of 0.2 mm x 0.2 mm area on the surface) in the meter photograph are counted. Degree). The number of occurrence points was 0 (zero), ◯ 1 to 3 or less, 4 to 6 △, 7 or more to ×, and 3 or less (◎ and ○) to pass.

  For the reflective film laminate after the heat resistance test, the visible light reflectance in light having a wavelength range of 38 to 780 nm was measured by the same method as in the measurement of the initial reflectance, and the difference from the initial reflectance [i.e., test Difference in reflectance before and after = initial reflectance (%)-reflectance after heat test (%)] and the heat resistance (that is, the degree of difficulty of Ag aggregation due to heat) is evaluated by the difference in reflectance. did. When the difference in reflectance was 3% or less, ◎ over 3% was 6% or less, ◯ was over 6%, 9% or less was Δ, over 9% was x, and 6% or less (（and ◯) was acceptable.

  Table 1 (Nos. 1 to 25) shows the results of the sulfidation test (sulfuration resistance evaluation results) and the heat resistance test results (heat resistance evaluation results). A part of the optical micrograph of the surface state (sulfurization state) of the reflection film laminate after the sulfidation resistance test is illustrated in FIGS. FIG. 2 is an optical micrograph of sample numbers: No. 1 and 23 (comparative example). FIG. 3 is an optical micrograph of Nos. 11 and 17 (Examples of the present invention).

  As can be seen from FIGS. 2 to 3, in the case of the comparative example (FIG. 2), black or brown sulfide points are observed in the entire visual field. In contrast, in the case of the example of the present invention (FIG. 3), the sulfidation point is hardly observed, and it is clear that the sulfidation resistance is excellent.

  As can be seen from Table 1, in the case of No. 1 to 10 (comparative example), the initial reflectivity is as good as 90% or more, but in the sulfidation resistance test, many sulfidation points are generated and the sulfidation resistance is × The level is not good. When the Bi concentration is less than 0.1 atomic% or when Bi is not included [No. 1-6, 8-10 (Comparative Example)], the effect of improving the heat resistance by adding Bi is not sufficient. The decrease in rate is large, and the heat resistance is at the level of x or Δ, which is insufficient. In addition, even when Mo or Hf is added, the addition amount is small (No. 9, 10 (Comparative Example)), and the effect of improving sulfidation is not obtained. Insufficient.

  In the case of No. 22 and 23 (comparative example), the initial reflectivity is as good as 90% or more, and although heat resistance is good at a level of ○, Fe and Ni are effective in improving sulfidation resistance. Therefore, the resistance to sulfidation is at the level of x, which is insufficient.

  In the case of Nos. 24 and 25 (comparative examples), although the sulfidation resistance and heat resistance are good, the initial reflectance is less than 90% because the A content is higher than the amount in the present invention.

  In the case of Nos. 11 to 21 (Examples of the present invention), the initial reflectivity is as good as 90% or more, and the sulfidation resistance is good at the level of ま た は or ◯, and further, heat resistance Is also good at ◎ or ○ level.

[Example 2]
In the same manner as in Example 1, an Ag alloy thin film (first layer) of various compositions was formed on a PC substrate, and a metal oxide layer (second layer) was formed on the first layer. Thus, a reflection film laminate was obtained. In forming the second layer, a target made of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , ZnO ₂ or SnO ₂ is used, and an Al ₂ O ₃ film, a TiO ₂ film, or a ZrO ₂ film is used. Then, a ZnO ₂ film or a SnO ₂ film was formed.

  The composition and thickness of the first layer and the composition and thickness of the second layer in the thus obtained reflective film laminate are shown in Table 2 (Nos. 26 to 39). For these reflective film laminates, the initial reflectance was measured by the same method as in Example 1, and thereafter, a sulfidation resistance test and a heat resistance test were performed by the same method as in Example 1 to obtain a sulfidation resistance and heat resistance. Sex was evaluated. The results are shown in Table 2 (Nos. 26 to 39).

As can be seen from Table 2 (No. 26 to 39), in the case of No. 34 to 39 (Comparative Example), the first layer satisfies the composition according to the present invention, but the second layer is a ZrO ₂ film, a ZnO film, or do not meet the composition of the present invention there is provided a SnO ₂ film. Among these, in the case of No. 34 and No. 35, although the initial reflectance is as good as 90% or more, the sulfidation resistance and the heat resistance are at the level of x, which is insufficient. In the case of No. 36 to 39, the initial reflectivity is less than 90%, the sulfidation resistance is at the level of x, and the heat resistance is at the level of Δ, and is insufficient. .

  On the other hand, in the case of Nos. 26 to 33 (Examples of the present invention), the initial reflectance is as good as 90% or more, and the sulfidation resistance is good at the level of ◎ or ◯, Furthermore, the heat resistance is also good at the level of ◎ or ○.

[Example 3]
In the same manner as in Example 1, an Ag alloy thin film (first layer) of various compositions was formed on a PC substrate, and a metal oxide layer (second layer) was formed on the first layer. Thus, a reflection film laminate was obtained. In forming the second layer, a target made of SiO ₂ , Al ₂ O ₃ , or TiO ₂ is used, and an SiO ₂ film, an Al ₂ O ₃ film, or a TiO ₂ film is formed. did.

  Table 3 shows the composition and film thickness of the first layer and the composition and film thickness of the second layer in the reflective film laminate thus obtained. About these reflective film laminated bodies, the initial stage reflectance was measured by the method similar to the said Example 1, and the constant temperature and humidity test hold | maintained on the following conditions was done after this.

[Constant temperature and humidity test]
・ Temperature: 50 ℃
・ Humidity: 95RH%
・ Time: 240 hours

  About the reflective film laminated body after a constant temperature and humidity test, the surface was observed visually, the number of white spots which generate | occur | produced by the constant temperature and humidity test was measured, and the generation | occurrence | production state of peeling was observed. At this time, the entire surface (φ50 mm × t1 mm) of the film forming portion of the reflective film laminate was observed, and those having the number of white spots within 2 were considered to be at a sufficiently excellent level. The results are shown in Table 3.

  Further, for the reflective film laminate after the constant temperature and humidity test, the reflectance was measured by the same method as in Example 1 above, and the difference from the initial reflectance [that is, the difference in reflectance before and after the test = initial reflectance (% ) -Reflectance after heat resistance test (%)] was determined, and the degree of difficulty of Ag aggregation in the constant temperature and humidity test was evaluated based on the difference in reflectance. This difference in reflectance is 2% or less, ◎ more than 2%, 5% or less, ◯, more than 5%, 8% or less, △, more than 8% x, and 5% or less (◎ and ○) are sufficiently excellent. It was assumed to be at the standard. The results are shown in Table 3.

  As can be seen from Table 3, in the case of Nos. 40 to 43, almost no white spots are generated, and one or two white spots are generated, which is sufficient in terms of difficulty in generating white spots. Is at an excellent level. The difference in reflectance before and after the constant temperature and humidity test is at the level of ◎ or ◯, and the degree of decrease in the reflectance in the constant temperature and humidity test is extremely small. Therefore, in the case of No. 40-43, moisture resistance is excellent. On the other hand, in the case of No. 44 and 45, since the film thickness of the second layer was large and the film stress was high, cracking and peeling occurred in the second layer in the constant temperature and humidity test. In addition, the degree of reduction in reflectance in the constant temperature and humidity test was increased. In addition, when the thickness of the second layer is 50 nm or less, such cracks and peeling do not occur, and as a result, the number of white spots is small, and the level is sufficiently excellent in terms of difficulty of white spots. The difference in reflectance between before and after the constant temperature and humidity test is at the level of ◎ or ◯, and the degree of decrease in the reflectance in the constant temperature and humidity test is extremely small. Therefore, in consideration of moisture resistance, the thickness of the second layer needs to be less than 60 nm, and is preferably 50 nm or less.

[Example 4]
In the same manner as in Example 1, an Ag alloy thin film (first layer) having the same composition as No. 12 and No. 17 in Table 1 was formed on a PC substrate with a film thickness of 300 nm, and on this first layer. A SiO ₂ film (second layer) was formed to a thickness of 10 nm to obtain a reflective film laminate (two-layer laminate type).

A part of the reflection film laminate (two-layer laminate) is set in a chamber of a plasma CVD apparatus as shown in FIG. 4 so that the inside of the chamber is 1 × 10 ⁻⁵ torr or less. A vacuum was pulled. Thereafter, the needle valve between the bubbler and the chamber in the apparatus was opened, the organic silicon vapor in the bubbler was introduced into the chamber, and the pressure in the chamber was adjusted to 0.1 torr by adjusting the degree of opening and closing of the needle valve. After that, RF is applied to the upper electrode in the chamber, plasma is generated with a power of 200 W, and a plasma polymerization film having a thickness of 40 nm is formed on the substrate (the two-layer laminate) to form a reflection film laminate (3 Layer stacking type) was obtained. Note that hexamethyldisiloxane was used as the organic silicon.

  The thus-obtained three-layered reflective film laminate and the two-layered reflective film laminate were subjected to an acid resistance test and an alkali resistance test by the following methods. That is, the acid resistance test was performed by immersing the reflective film laminate in a 1 mass% (1 wt%) sulfuric acid aqueous solution at 25 ° C. for 20 minutes. The alkali resistance test was performed by immersing the reflective film laminate in a 1 mass% potassium hydroxide aqueous solution at 25 ° C. for 20 minutes.

The cross section of the reflective film laminate after the acid resistance test and the alkali resistance test was observed with a scanning electron microscope. In the case of a two-layer laminated type reflection film laminate, it was found that the SiO ₂ film (second layer) was dissolved in a sulfuric acid aqueous solution or a potassium hydroxide aqueous solution, resulting in a single-layer structure consisting of only an Ag alloy layer. . On the other hand, in the case of a three-layered laminated reflective film laminate, it was found that the three-layer structure was maintained both after the acid resistance test and after the alkali resistance test. Therefore, it was confirmed that the acid resistance and alkali resistance were remarkably improved by the lamination of the plasma polymerization film.

  The reflective film laminate according to the present invention is less likely to cause aggregation and sulfidation of Ag. Therefore, the reflective film laminate can be suitably used as a reflective film laminate for lighting fixtures and automobile headlamps, and its durability is improved. And useful.

6 is a schematic diagram showing a sputtering apparatus used for production (film formation) of a reflective film laminate according to Example 1. FIG. It is a figure which shows the surface state after the sulfidation resistance test about the reflective film laminated body which concerns on a comparative example. It is a figure which shows the surface state after the sulfidation resistance test about the reflective film laminated body which concerns on the Example of this invention. 6 is a schematic view showing a plasma CVD apparatus used for forming a plasma polymerization film according to Example 4. FIG.

Claims (6)

A reflective film laminate used for lighting fixtures or automobile headlamps, containing Ag as a main component and 0.08 to 2.0 atomic% of Bi on a substrate, and Ti, V, Cr, Zr, Nb, Mo, Hf, A first layer made of an Ag alloy containing a total of 0.1 to 3.0 atomic% of one or more of Ta and W is formed, and a second layer made of one or more metal oxides of Si, Al, and Ti is formed thereon. A reflecting film laminate, characterized in that it is formed.   The reflective film laminate according to claim 1, wherein the thickness of the first layer is 200 nm or more.   The reflective film laminate according to claim 1 or 2, wherein the second layer has a thickness of 2 to 50 nm.   The reflective film laminate according to any one of claims 1 to 3, wherein the Ag alloy contains a total of 0.1 to 5 atomic% of one or more of Au, Pt, Pd, and Rh.   The reflective film laminate according to any one of claims 1 to 4, wherein the visible light reflectance measured by light having a wavelength range of 380 to 780 nm with a D65 light source in accordance with JIS R3106 is 90% or more.   The reflective film laminate according to claim 1, wherein a plasma polymerization film is formed on the second layer.

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