JP3544772B2 - reflector - Google Patents

Description

【００３５】
また、実施例１〜６で作製した試料と、比較例１〜２で作製した試料を、１５０℃に加熱した台に置き、１００Ｗのハロゲンランプを薄膜から１０ｃｍ離したところに設置し、光照射と加熱を同時に行い銀薄膜の安定性を反射率を測定することにより加熱前および５００時間後の反射率を評価した。その結果を表２に示す。なお、反射率は、金属面でない側、すなわち、高分子フィルム側から分光光度計Ｕ３４００（日立）を用い、反射率すなわち、鏡面反射率＋拡散反射率を測定した。
【００３６】
【表２】

【００３７】
【発明の効果】
透明高分子フィルムと銀薄膜層の間に薄い、好ましくは０．５乃至３ｎｍのチタン、タングステン、もしくは銅から選ばれた少なくとも一つの金属層を用いて、かつ接着層に熱硬化型接着剤を用い、金属板とラミネートすることにより、高温環境下においても安定な反射板を得ることができる。これにより、該反射板を１５０℃の温度において５００時間大気中で加熱を行った後においても、９０％以上の反射率を保ち、複写機に好適に使用できる反射板を提供できる。
【図面の簡単な説明】
【図１】本発明の反射板の一例を示す断面図
【図２】本発明の反射板の一例を示す断面図
【符号の説明】
１０ 透明高分子フィルム
２０ チタン、タングステン、もしくは銅から選ばれた少なくとも一つの金属層
３０ 銀薄膜層
４０ 接着層
５０ 支持体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflective plate using stable silver, and more particularly, to a reflective plate using silver which has a small decrease in reflectance even in a high-temperature environment and which can be suitably used in a copying machine.
[0002]
[Prior art]
Silver is a metal having the highest reflectance in the visible light region, and is described as having a reflectance of 97.9% in the Physical Chemistry, page 99 of the Science Chronology Table (edited by Tokyo Astronomical Observatory, 1975). . Therefore, silver is considered to have excellent performance as a reflecting member. However, since silver itself is an unstable metal, it is known that if it is left for a long time while being exposed to the atmosphere at a high temperature of 150 ° C. or higher, the reflectance of the surface is reduced. Therefore, various alloying methods have been attempted to change the color of silver. For example, an alloy to which at least 50 atomic% of gold or platinum or a platinum group such as palladium is added is known as an invariable color alloy (actual knowledge of precious metals, written by Yuzo Yamamoto, Toyo Keizai Shinposha, page 146). However, although the silver alloy is invariable in color, its reflectance is lower than the value inherent in silver, so that its value as a reflecting material cannot be sufficiently utilized.
Aluminum is an alternative to silver. Although the reflectivity of aluminum is 91.6%, which is described in the science chronological table (supra), 90% is the highest value in practical use. Therefore, when silver is used as a reflector, 90% or more is a measure of practical performance.
[0003]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a reflector which can improve the stability in a high-temperature environment and maintain the reflectance even in a high-temperature environment.
[0004]
[Means for Solving the Problems]
The present inventors have studied earnestly a method of improving the stability of a reflector using silver in a high-temperature environment and maintaining a high reflectance over 500 hours or more in a high-temperature environment. By using the layer between the transparent polymer film and the silver thin film layer, the heat stability of the reflector using silver is remarkably improved, and the reflector is laminated on a metal plate, which is suitable for a copying machine or the like. The present inventors have found that a reflector plate that can be used for the present invention has been obtained, and arrived at the present invention.
[0005]
That is, the present invention has been made to solve the above problems,
(1) At least a transparent polymer film (A), a silver thin film layer (B), an adhesive layer (C), and a reflecting plate having a polymer film side of a ABCD composed of a support (D) as a reflecting surface, A reflector having a reflectance of 90% or more measured from the polymer film side even after heating in the air at a temperature of 150 ° C. for 500 hours;
(2) AEBCD comprising at least one thin metal layer (E) selected from titanium, tungsten or copper between a transparent polymer film (A) and a silver thin film layer (B) (1) Reflector,
(3) The AEBECD has a structure in which at least one thin metal layer (E) selected from titanium, tungsten, or copper is provided between the silver thin film layer (B) and the adhesive layer (C) (2). Reflector,
(4) the reflector of (2) or (3), wherein the thickness of the metal layer (E) is 0.5 to 3 nm;
(5) The reflecting plate according to any one of (1) to (4), wherein the transparent polymer film (A) is polyether sulfone, polyether ether ketone, polyimide, polycarbonate, or polyarylate;
(6) The adhesive layer (C) relates to any one of (1) to (5), which is a thermosetting adhesive.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The reflection surface is a boundary surface that changes the direction of incident light and returns to the original medium, and corresponds to, for example, an interface between the polymer film (A) and the silver thin film layer (B). However, in a reflector, the side (surface) used for reflection may be referred to as a reflection surface, and the reflection surface referred to in the present invention refers to the side (surface) used exclusively for the latter reflection.
[0007]
The present invention, as shown in FIG. 1, on a transparent polymer film 10, at least one thin metal layer 20 selected from titanium, tungsten or copper, and on the metal layer 20, a silver thin film layer 30, It is a reflector composed of an adhesive layer 40 and a support 50, in which a metal layer is present between a transparent polymer film and a silver thin film layer. In addition, as shown in FIG. 2, in the reflector in which at least one thin metal layer 20 selected from titanium, tungsten, or copper is formed on both main surfaces of the silver thin film layer 30, that is, in the reflector of FIG. Further, there may be mentioned one in which a metal layer is provided also between the silver thin film layer and the adhesive layer.
[0008]
The silver thin film (silver thin film layer) referred to in the present invention is preferably formed by using a vacuum such as a vacuum evaporation method or a sputtering method. In the vacuum evaporation method, silver is melted in a crucible by resistance heating or electron beam heating, and the vapor pressure is increased to form a thin film on a desired polymer film. Examples of the sputtering method include a high-frequency sputtering method, a direct-current sputtering method, a high-frequency magnetron sputtering method, a direct-current magnetron sputtering method, and an electron cyclotron resonance sputtering method. In the sputtering method, a solid silver target is used. Usually, an argon gas is introduced into a vacuum vessel at about 1 to 10 mTorr and used as a sputtering gas, but krypton or neon may be used. Although the purity of the silver of the target is not particularly limited, it is preferably 99.9% or more, more preferably 99.99% or more.
[0009]
The thickness of the silver thin film layer is preferably from 70 nm to 300 nm, more preferably from 100 nm to 200 nm. If the thickness is too thin, the thickness of silver is insufficient, so that there is transmitted light and the reflectance is reduced. On the other hand, if the film thickness is too large, exceeding 300 nm, the reflectance does not increase and shows a tendency to saturate, and the adhesion of the silver thin film layer to the polymer film is undesirably reduced.
[0010]
In the present invention, the transparent polymer film is not particularly limited as long as it is transparent and can withstand continuous use at 150 ° C. or higher, and a polyethersulfone, a polyetheretherketone, a fluorine-based film such as fluoroethylenepropylene, Polymer films such as polyimide, polycarbonate, and polyarylate films can be used. At that time, before forming the silver thin film, it is necessary for a person skilled in the art to perform chemical cleaning treatment, surface roughening treatment, glow discharge treatment, corona discharge treatment, etc. on the polymer film surface to improve adhesion and the like. Will be easy to understand.
[0011]
The thickness of the polymer film is not limited, but is preferably about 25 to 100 μm. The optical characteristics of the polymer film used are preferably such that the light transmittance at a wavelength of 550 nm is 80% or more. More preferably, the light transmittance is 80% or more for light having a wavelength of 500 to 700 nm, and further preferably, the light transmittance is 80% or more for light having a wavelength of 350 to 750 nm. If the light transmittance is much lower than 80%, the reflectance of the reflector becomes less than 90%, which is not preferable in terms of performance as a reflector.
[0012]
As an adhesive (including an adhesive) used as the adhesive layer of the present invention, a thermosetting adhesive in which a chemical reaction proceeds by heating in a curing process after being applied to and bonded to the adhesive is suitable. Adhesives, acrylic adhesives, melamine adhesives, silicone adhesives, epoxy adhesives, phenolic adhesives, etc., and those obtained by mixing two or more of these adhesives, are not necessarily included in these types. It is not limited, and it is sufficient that the adhesive has practical adhesive strength. After heating at 90 ° C. or higher, the adhesive strength is measured at 180 ° peel strength and 100 g / cm is sufficient, preferably 500 g / cm, more preferably 1000 g / cm. When it does not reach 100 g / cm, when the reflective plate is bent to a radius of curvature of about 1 to 5 mm, the transparent polymer film side may undesirably rise above the metal plate as the support, which is not preferable.
[0013]
The thickness of the adhesive layer is 0.5 μm to 50 μm, preferably 1 μm to 20 μm.
Examples of the method of applying the adhesive include a bar coating method, a Meyer bar coating method, a reverse coating method, a gravure coating method, a die coating method, and a roll coating method. Is selected in consideration of the coating speed, the obtained surface condition, and the like.
[0014]
The temperature and time required for curing the adhesive vary depending on the type and amount of the adhesive, the amount of the support, the type of the support, etc., but are suitably 80 to 300 ° C. and 0.1 seconds to 2 hours, preferably 100 to 250 ° C. ° C, 0.1 second to 30 minutes.
[0015]
A support is used for workability, shape retention, and the like. Preferably, the support is a metal plate of aluminum, aluminum alloy, stainless steel, steel zinc alloy, steel, or the like. Each of these metals has advantages and can be used properly as follows. Aluminum is lightweight and excellent in processability, and has a high thermal conductivity and can effectively release the heat to the atmosphere. Therefore, it can be suitably used for a copying machine in which a reflector is heated by lamp emission. In addition, aluminum alloys can be suitably used because they are lightweight and have high mechanical strength, and stainless steels can be suitably used because they have high mechanical strength and excellent corrosion resistance. Further, a steel-zinc alloy, that is, brass or brass, can be suitably used because of its high mechanical strength and easy soldering. The thickness of the support is preferably about 0.1 to 1 mm.
[0016]
The heating test at 150 ° C. can be performed in a normal electric furnace, and the atmosphere is in the air. The term "in the air" here falls within the range of a normal living environment in which the reflector is used, and does not specify a special environment.
[0017]
The reflectance of the reflector referred to in the present invention indicates the reflectance using an integrating sphere, that is, the sum of specular reflection and diffuse reflection. The reflectance can be measured, for example, by using a spectrophotometer U3400 manufactured by Hitachi equipped with an integrating sphere unit.
[0018]
The method for producing at least one thin metal layer selected from titanium, tungsten, or copper, which is provided between the polymer film and the silver thin film layer, preferably further provided between the silver thin film layer and the adhesive layer, is a silver thin film layer. Similarly to the above, the layers can be laminated by a vacuum deposition method, a sputtering method, or the like, but the sputtering method is preferably employed rather than the vacuum deposition method because tungsten has a high melting point.
[0019]
The thickness of at least one thin metal layer selected from titanium, tungsten, or copper may be in a range in which a sufficient decrease in reflectance can be suppressed without impairing the reflectance. The range is desirably, more desirably, the range of 0.5 nm to 2 nm. Note that a plurality of the metal layers may be stacked.
[0020]
For the measurement of the thickness of the metal layer, there are a stylus roughness meter, a repetitive reflection interferometer, a microbalance, a crystal oscillator method, and the like. It is suitable for obtaining a desired film thickness. There is also a method in which the conditions for film formation are determined in advance, a film is formed on a test substrate, the relationship between the film formation time and the film thickness is examined, and the film thickness is controlled by the film formation time. For example, when the thickness of the thin film formed for M (seconds) is measured by a stylus roughness meter and found to be D (nm), to obtain a film thickness of d (nm), the following formula is used. , The film forming time T (second) is determined. That is, T = d × (M / D). For example, in a sputtering method, when tungsten is formed for 1000 seconds and 100 nm of tungsten is obtained, it is sufficient to form a tungsten film of 1 nm under the same film formation conditions for 10 seconds.
[0021]
Further, when the film thickness is determined by the crystal oscillator method, if the frequency of the crystal oscillator decreases by F (Hz) when a film having a film thickness of D (nm) is produced, d (nm) film formation is performed. The thickness is determined when the frequency f (Hz) obtained by the following equation decreases. That is, f = d × (F / D). Here, D may be determined using a stylus roughness meter, a repetitive reflection interferometer, or the like.
[0022]
In the present invention, the film thickness is determined by such a method, and the thin film layer referred to in the present invention does not need to be a common-sense continuous film or continuous layer, for example, an island-like structure. May be provided. This has also been pointed out in a compendium (for example, “Basic Technology of Thin Films” by Kanu Kanehara, published by the University of Tokyo, pages 89 to 94).
[0023]
The thin metal layer having a thickness of 0.5 to 3 nm is, of course, very unstable, and is oxidized during or after film formation by a residual gas in vacuum or impurities in the polymer or on the polymer. It will be easily understood by those skilled in the art that the state has been changed and the state is not completely metallic.
It should be noted that the state of the metal layer can be investigated by X-ray photoelectron spectroscopy, Auger electron spectroscopy, or the like.
[0024]
If an example of the actual manufacturing method of the reflector of the present invention is specifically illustrated, titanium, tungsten, or copper is formed on a transparent polymer film by a sputtering method or the like, and then silver is formed. Titanium, tungsten, or copper may be deposited. The sputtering may be a batch method or a roll-to-roll method. Subsequently, it is manufactured by applying a thermosetting adhesive by a bar coating method and laminating the same with a steel plate or an aluminum plate by a hot roll.
[0025]
【Example】
Hereinafter, the present invention will be described based on examples and comparative examples.
(Example 1)
A 0.5 nm titanium film is formed on polyethersulfone (Mitsui Toatsu TALPA1000: 50 μm thickness) by sputtering, followed by a 150 nm silver film, and then a 0.5 nm titanium film. Was formed, a saturated polyester / melamine resin-based adhesive was applied by a bar coating method, and laminated with a steel plate having a thickness of 0.3 mm to obtain a reflection plate.
[0026]
(Example 2)
A 0.5 nm titanium film is formed on polyetheretherketone (Mitsui Toatsu TALPA2000: 50 μm thick) by sputtering, followed by a 150 nm silver film, and then a 0.5 nm titanium film. Was formed, a saturated polyester / melamine resin-based adhesive was applied by a bar coating method, and laminated with a steel plate having a thickness of 0.3 mm to obtain a reflection plate.
[0027]
(Example 3)
A 0.5 nm tungsten film is formed on polyether sulfone (Mitsui Toatsu TALPA1000: thickness 50 μm) by a sputtering method, followed by a 150 nm silver film formation, and an epoxy resin adhesive is applied by a roll coating method. It was applied and laminated with an aluminum plate having a thickness of 0.2 mm to obtain a reflection plate.
[0028]
(Example 4)
A 0.5 nm tungsten film is formed on polyetheretherketone (Mitsui Toatsu TALPA2000: thickness 50 μm) by sputtering, followed by a silver film of 150 nm, and an epoxy resin adhesive is applied by roll coating. It was applied and laminated with an aluminum plate having a thickness of 0.2 mm to obtain a reflection plate.
[0029]
(Example 5)
A 0.5 nm copper film is formed on polyether sulfone (Mitsui Toatsu TALPA1000: thickness 50 μm) by a sputtering method, followed by a silver film of 150 nm, and a phenolic adhesive is applied by a bar coating method. It was applied and laminated with a brass plate having a thickness of 0.3 mm to obtain a reflection plate.
[0030]
(Example 6)
A 0.5 nm copper film is formed on polyetheretherketone (Mitsui Toatsu TALPA2000: thickness 50 μm) by sputtering, followed by a 150 nm silver film, and a phenolic adhesive is applied by a bar coating method. It was applied and laminated with a yellow steel plate having a thickness of 0.3 mm to obtain a reflection plate.
A silver thin film was obtained.
[0031]
(Comparative Example 1)
A 150 nm silver film is formed on polyether sulfone (Mitsui Toatsu TALPA1000: thickness 50 μm) by a sputtering method, and a saturated polyester / melamine resin-based adhesive is applied by a bar coating method. A reflector was obtained by lamination with a steel plate.
[0032]
(Comparative Example 2)
A 150 nm silver film is formed on polyetheretherketone (Mitsui Toatsu TALPA2000: thickness 50 μm) by a sputtering method, and a saturated polyester / melamine resin-based adhesive is applied by a bar coating method. A reflector was obtained by lamination with a steel plate.
[0033]
The samples prepared in Examples 1 to 6 and the samples prepared in Comparative Examples 1 and 2 were placed in an electric furnace set at 150 ° C., held for 500 hours, taken out, measured for reflectance, and heated. The reflectance was measured before and after. Table 1 shows the results.
[0034]
[Table 1]

[0035]
The samples prepared in Examples 1 to 6 and the samples prepared in Comparative Examples 1 and 2 were placed on a table heated to 150 ° C., and a 100 W halogen lamp was placed 10 cm away from the thin film. And heating were performed simultaneously, and the reflectance of the silver thin film before and after 500 hours was evaluated by measuring the reflectance. Table 2 shows the results. The reflectance was measured by using a spectrophotometer U3400 (Hitachi) from the side other than the metal surface, that is, from the polymer film side, that is, the reflectance, that is, the specular reflectance + diffuse reflectance.
[0036]
[Table 2]

[0037]
【The invention's effect】
A thin, preferably 0.5 to 3 nm, at least one metal layer selected from titanium, tungsten or copper is used between the transparent polymer film and the silver thin film layer, and a thermosetting adhesive is used for the adhesive layer. When used and laminated with a metal plate, a stable reflector can be obtained even in a high-temperature environment. Thus, even after the reflector is heated at 150 ° C. for 500 hours in the atmosphere, a reflector that maintains a reflectance of 90% or more and can be suitably used in a copying machine can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a reflector of the present invention. FIG. 2 is a cross-sectional view illustrating an example of a reflector of the present invention.
10 Transparent polymer film 20 At least one metal layer 30 selected from titanium, tungsten or copper 30 Silver thin film layer 40 Adhesive layer 50 Support

Claims (6)

At least, a transparent polymer film (A), silver thin film layer (B), adhesive layer (C), a polymer film side of the structure ABCD comprising a support (D) in the reflector to the reflecting surface, a transparent polymer AEBCD comprising at least one thin metal layer (E) selected from titanium, tungsten or copper between the film (A) and the silver thin film layer (B), wherein the thickness of the metal layer (E) is A reflector having a reflectivity of 90% or more measured from the polymer film side even after heating in air at a temperature of 150 ° C. for 500 hours at a temperature of 0.5 to 3 nm . Wherein between the silver thin film layer (B) and the adhesive layer (C), made of titanium, tungsten, or at least one thin metal layer (E) from the configuration AEBECD provided selected from copper, a metal layer (E) 2. The reflector according to claim 1 , wherein the thickness of said reflector is 0.5 to 3 nm . The reflector according to any one of claims 1 to 2, wherein the transparent polymer film (A) is polyethersulfone, polyetheretherketone, polyimide, polycarbonate, or polyarylate. The adhesive layer (C) is, the reflection plate according to any one of the claims 1 to 3 is a thermosetting adhesive. The reflection according to any one of claims 1 to 4, wherein the adhesive layer (C) has an adhesive strength of 90 ° C or higher, and then measures 180 ° peel strength and is at least 100 g / cm or higher. Board. The reflector according to any one of claims 1 to 5, wherein the thickness of the adhesive layer (C) is 0.5 to 50 µm.

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