JP3501231B2 - Heat reflective film - Google Patents

Description

Detailed Description of the Invention

[0001]

[Industrial application] The present invention relates to a heat ray reflective thin film (material) that utilizes the property of reflecting and absorbing infrared rays.

[0002]

2. Description of the Related Art Conventionally, sunlight that flows through a window glass into a room, an automobile, a cooling container or the like is partially cut to reduce an increase in indoor temperature or to reduce a cooling load. Infrared reflection / absorption films and glass have been developed in order to block outflow of infrared rays and improve heating efficiency. To date, transparent oxide / Ag / transparent oxide constitution (Japanese Patent Publication No. 47-8315), transparent dielectric or transparent conductor / nitride / transparent dielectric or transparent conductor constitution (Japanese Patent Publication No. 63-206332) Etc. are known.

On the other hand, as a method for producing a composition-modulated thin film and an artificial lattice thin film, there is known a method utilizing opening / closing of a shutter (Japanese Patent Laid-Open No. 58-215610) and a method of moving a crucible (Japanese Patent Laid-Open No. 59-184799). Has been. Deposition on a film roll is generally performed continuously while winding the roll. In the case of forming a film having a three-layer structure, three evaporation sources are arranged and vapor deposition is performed, or vapor deposition is performed while winding three times.

[0004]

However, the transparent oxide /
The composition of Ag / transparent oxide (Japanese Examined Patent Publication No. 47-8315) is inferior in stability over time due to poor scratch resistance and chemical durability. Further, the structure of transparent dielectric or transparent conductor / nitride / transparent dielectric or transparent conductor (Japanese Patent Publication No. 63-20).
6332) and the like, the production is limited to the sputtering method and is not suitable for high speed film formation. Further, in order to form a film having a three-layer structure, the apparatus is complicated because three vapor deposition sources are arranged, or vapor deposition is performed while winding three times, which increases the production time.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a heat ray reflective thin film which has good stability over time and is suitable for high speed film formation. That is, the present invention is a heat ray reflective thin film (material) characterized in that a thin film having a composition modulation periodic structure in the film thickness direction is deposited by one or more kinds of metal and transparent oxide respectively, and the thin film. Is a heat ray reflection plate or heat ray reflection film.

The heat ray reflective thin film as used in the present invention is a material that transmits or absorbs infrared rays by reflecting or absorbing infrared rays, but transmits visible rays. The visible light transmittance is preferably 60% or more, more preferably 70% or more, and the light transmittance property of the infrared transmittance is preferably 60% or less.

The term "metal" as used in the present invention means a single metal or an alloy or mixture of two or more kinds of metals, which has absorption in the infrared region, and is preferably Fe, Co, V, Pt, Ti, Mo, Ta,
Nb, Mg, Ca, Al, Sn, Sb, Ge, Si, more preferably Au, A
g, Cu, Pd, Ni, Cr. The total thickness of the metal layers in the film is not particularly limited as long as it satisfies the required characteristics as a visible light transmitting film, but is preferably 70 nm or less, more preferably 30 nm or less. Further, in order to have the infrared light reflection property, it is necessary to have at least 5 nm or more, and preferably 10 nm or more. Here, the expression of the total thickness is converted by the ratio of the metal in the thin film of the present invention. For example, the total thin film thickness is 1000n
m, and if the ratio of the metal is 5%,
50 nm is the total thickness of the metal layers.

The metal oxide as referred to in the present invention is a simple oxide and a composite oxide of two or more kinds of metals. The simple oxide composition refers to an oxide composed of one kind of metal and oxygen.
For example, AlO ₂ , Al ₂ O ₃ , CeO ₂ , SiO, Si
O ₂ , MgO, TiO ₂ , ZrO ₂ , Nd ₂ O ₃ , Pb
O, ThO _{2 and the} like. Impurities may be included in the simple oxide composition within a range (about 3%) that does not impair the purpose. A composite oxide is a mixture or compound of two or more kinds of oxides, such as Al ₂ O ₃ —SiO ₂ ,
_{SiO-SiO 2, Al 2 O} 3 -MgO-SiO 2, B
aTiO ₃ (BaO-TiO ₂ ), PbTiO ₃ , Zn
_{O-Al 2 O 3, ZnO} -BiO 3, TiO 2 -SiO
_{2, BaO-Al 2 O 3} -SiO 2, Y 2 O 3 -ZrO
Compound oxides such as ₂ are known, but not limited thereto.

The compositional modulation referred to in the present invention means that the composition of the thin film in the film thickness direction is such that the ratio of two or more kinds of components continuously changes in the film thickness direction . The compositional modulation in the present invention is preferably 6 when the composition of the metal is maximum.
The range is 0% or more, more preferably 70% or more, and preferably 40% or less, and more preferably 30% or less when the metal composition is minimized. Further, the shape of the change of the composition in the film thickness direction is not particularly limited, but pseudo triangular wave, sine wave, square wave, rectangular wave,
Alternatively, a square wave having a rising and falling slope may be considered. The rate of composition change in the film thickness direction is at most 50 at% / nm or less, preferably 30 at%
/ Nm or less, and more preferably 20 at% / nm or less. Needless to say, this also includes the case where the shape of the change in the film thickness direction of this composition is disturbed. The composition ratio does not have to be constant and the amplitude does not have to be constant. The term “periodic structure” as used in the present invention means that the compositional modulation forms a periodic structure of at least two times. That is, when the composition of the thin film is investigated in the film thickness direction, the ratio of two or more components continuously changes in the film thickness direction, and this change in the component ratio is periodic. Here, “periodically” means that the shape of composition change in the film thickness direction has a similar pattern and is repeated. Due to the periodic composition modulation structure, due to scattering at the interface, etc., it has an infrared reflection characteristic equal to or higher than that of a single layer film (film of a single composition). Even if this cycle is three times, the heat ray reflection performance is obtained. However, 5 times or more is preferable, and more preferably 10 times or more, the durability is improved. The composition modulation period in the present invention is 2 to 3
It is preferably within the range of 5 nm, more preferably 5 to 15
It is in the range of nm.

The term "transparent substrate" as used in the present invention refers to a material transparent in the visible range, and examples thereof include an organic resin sheet and glass. These are conceivable for roofs, greenhouses, buildings, household windows, etc. Even when visible light has light absorption, it is included in a transparent substrate when infrared absorption or infrared reflection is weak and improvement of this is desired.

The plastic film referred to in the present invention is
It is a film obtained by melt-extruding an organic polymer and, if necessary, stretching, cooling, and heat setting in the longitudinal direction and / or the width direction. Examples of the organic polymer include polyethylene, polypropylene, and polyethylene terephthalate. , Polyethylene-2,6-naphthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamideimide, polyimide, polyetherimide, polysulfone, Examples thereof include polyphenylene sulfide and polyphenylene oxide. Further, these (organic polymer) organic polymers may be copolymerized or blended with a small amount of another organic polymer.

Further, known additives such as an ultraviolet absorber, an antistatic agent, a plasticizer, a lubricant and a coloring agent may be added to the organic polymer, and its transparency is not particularly limited. Absent. The plastic film of the present invention may be subjected to corona discharge treatment, glow discharge treatment, or other surface roughening treatment prior to laminating the thin film layers, as long as the object of the present invention is not impaired. Also, known anchor coat treatment, printing, and decoration may be applied. The thickness of the plastic film of the present invention is preferably in the range of 5 to 500 μm,
More preferably, it is in the range of 8 to 300 μm.

Various vacuum vapor deposition methods, sputtering methods, CVD methods and the like are used for producing a thin film having such a composition modulation periodic structure. Among these, vacuum vapor deposition gives the highest deposition rate, and therefore is an example, but the present invention is not limited to this. Regarding the vacuum vapor deposition method, the heating method may be a single EB gun or a plurality of heating methods, or may be another heating method or a combination thereof. Other heating methods referred to here include resistance heating, high frequency induction heating, and laser beam heating, but the heating method is not limited thereto. Further, with respect to the vacuum vapor deposition method and the sputtering method, the present invention is also applied to reactive vapor deposition and sputtering in which oxygen, nitrogen, water vapor or the like is introduced as a reactive gas or ozone, ion assist or the like is used. it can. Further, there is no problem even if the deposition conditions are changed such as applying a bias to the substrate, raising the substrate temperature or cooling the substrate. The same applies to the sputtering method and the CVD method.

The heat ray reflective thin film of the present invention has the above-mentioned structure and can be manufactured by various thin film manufacturing methods.
Therefore, if a film forming method is selected, high speed film forming is possible. Further, since the composition-modulated structure is adopted, it is possible to manufacture a film having essentially good durability, and it has an infrared reflection characteristic equal to or higher than that of a single-layer film. Of course, another single film or a composite film may be added to the outer layer or the inner layer of the thin film having the composition-modulated periodic structure of the present invention. Next, examples of the present invention will be described.

[0015]

EXAMPLES Example 1 A thin film was formed by electron beam evaporation.
(FIG. 1) As a vapor deposition source, particulate Ag and SiO ₂ (purity 99.9%) having a size of about 3 to 5 mm were used, and a PET film of 100 μm thickness (Toyobo ( A thin film was formed on E5100). The vapor deposition material was not mixed and the inside of the hearth was partitioned into two by a carbon plate. The film feed speed was 100 m / min, one electron gun (hereinafter referred to as EB gun) was used as a heating source, and Ag and S
Each of the iO ₂ was heated in a time division manner to form a composition modulation film of Ag and SiO ₂ . The emission current of the EB gun at that time was 1.2 A, and the heating ratio of Ag to SiO ₂ was
It was set to 5:10 and a film having a thickness of about 50 nm was formed. And
A deposition preventive plate was installed between the film and the vapor deposition source. The opening was 20 cm with respect to the running direction of the film. The time for the film to run through this opening is 0.12 seconds.
The electron beam scan is performed at 75 Hz. In other words, the electron beam is scanned every 0.013 seconds. Therefore, the electron beam is scanned 9 times during the time that the film travels through the opening for 0.12 seconds. Still other conditions were constant, and the scan speed of the electron beam was halved to prepare a sample.

From the starting position of vapor deposition of the long film thus produced, sampling was conducted at 20, 100, 500, 1000 m, etc., and depth direction composition analysis (Auger electron spectroscopy) was carried out. It showed almost the same profile. These profiles show compositionally modulated structures. (Fig. 2) Compositional modulation is 75% when the composition of the metal is maximum, 25% when the composition of the metal is minimum,
The waveform of the change in the composition in the film thickness direction was sinusoidal.
The compositional modulation had a periodic structure of 9 times, and the modulation period was 6 nm. When the electron beam scan speed was halved under the other conditions being constant, compositional modulation was 80% when the metal composition was the maximum, 20% when the metal composition was the minimum, and The waveform of the change in the film thickness direction was sinusoidal. The compositional modulation had a periodic structure of 5 times, and the modulation period was 11 nm. Further, the visible and infrared spectral luminosity characteristics of this film were measured. (FIG. 3) Performance equivalent to that of Comparative Example 1 having a three-layer structure was obtained. A film having good transmission characteristics in the visible region and non-transparency in the infrared region was obtained.
Furthermore, the temporal change of the spectral characteristics of this film was examined. (Table 1) As the initial reflectance, the reflectance in infrared (wavelength 10 μ) was measured. Infrared (wavelength 1
The time until the reflectance at 0 μ) reached 85% was measured as the deterioration time. As a result, a heat ray reflective thin film excellent in stability over time was obtained.

[Table 1]

For the Auger, the above measurement is Ag-
MNN, Au-MNN, Si-LMM, Ti-LMM,
The composition distribution in the depth direction was obtained by performing measurement while sputtering the thin film using the Auger transition signal of O-KLL. The spectrophotometric characteristics were measured in the range of 0.4 μm to 10 μm.

(Example 2) The procedure of Example 1 was repeated except that the oxide was TiO ₂ . The period of compositional modulation measured by Auger electron spectroscopy was 12 nm,
The compositional modulation was 75% when the metal composition was the maximum, 25% when the metal composition was the minimum, and the waveform of the compositional change in the film thickness direction was sinusoidal. The composition modulation has a periodic structure of 5 times. The infrared spectral characteristics of this sample were measured in the same manner as in Example 1.

Example 3 The same method as in Example 1 was used except that the metal layer was Au. When the period of compositional modulation was measured by Auger electron spectroscopy, it had a periodic structure of 5 times,
It was 10 nm. The compositional modulation was 70% when the metal composition was the maximum, 30% when the metal composition was the minimum, and the waveform of the change of the composition in the film thickness direction was sinusoidal. The infrared spectral characteristics of this sample were measured in the same manner as in Example 1.

Example 4 The same method as in Example 1 was used except that ZrO _{2 was} used as the oxide and Au was used as the metal layer. When the period of compositional modulation was measured by Auger electron spectroscopy, it had a periodic structure of 5 times and was 10 nm. The compositional modulation was 75% when the metal composition was the maximum, 25% when the metal composition was the minimum, and the waveform of the compositional change in the film thickness direction was sinusoidal. Infrared spectroscopic characteristics of this sample were measured in the same manner as in Example 1 having a periodic structure with composition modulation of 9 times.

(Comparative Example 1) SiO ₂ (12.5 nm) /
It had a three-layer structure of Ag (25 nm) / SiO ₂ (12.5 nm). For this reason, the film was sent for each layer and three times of winding vapor deposition were performed. EB vapor deposition was performed on the PET film in the same manner as in Example 1, and the infrared spectral characteristics were measured in the same manner as in Example 1. The temporal stability of the spectrophotometric characteristics investigated was insufficient. The thin film deposition time is the same as in Example 1.
It took 3 times. In addition, when looking at the entire evaporation, it took 90 minutes to rewind the film and 10 minutes to evaporation, so it took 200 minutes more.

Comparative Example 2 TiO ₂ (12.5 nm) /
It had a three-layer structure of Ag (25 nm) / TiO ₂ (12.5 nm). For this reason, the film was sent for each layer and three times of winding vapor deposition were performed. Except for this, it was manufactured by the same method as in Example 1, and the infrared spectral characteristics were measured in the same manner as in Example 1. The temporal stability was insufficient. The thin film deposition time was three times as long as that in Example 1, as in Comparative Example 1. In addition, when looking at the entire evaporation, it took 90 minutes to rewind the film and 10 minutes to evaporation, so it took 200 minutes more.

Comparative Example 3 SiO ₂ (12.5 nm) /
The Au (25 nm) / SiO ₂ (12.5 nm) three-layer structure was adopted. For this reason, the film was sent for each layer and three times of winding vapor deposition were performed. Except for this, the same method as in Example 1 was used. The infrared spectral characteristics were measured in the same manner as in Example 1. The temporal stability was insufficient. The thin film deposition time was the same as in Comparative Example 1.

(Comparative Example 4) ZrO ₂ (12.5 nm) /
The Au (25 nm) / ZrO ₂ (12.5 nm) three-layer structure was adopted. For this reason, the film was sent for each layer and three times of winding vapor deposition were performed. Except for this, the same method as in Example 1 was used. The infrared spectral characteristics were measured in the same manner as in Example 1. The temporal stability was insufficient. The thin film deposition time was the same as in Comparative Example 1.

(Comparative Example 5) SiO and Ag were vapor-deposited at the same time to obtain a SiO-Ag composite film. At this time, the scanning speed of the electron gun was made sufficiently high to form a composite film. Except for this, the same method as in Example 1 was used. The infrared spectral characteristics were measured in the same manner as in Example 1. The temporal stability was insufficient.

[0026]

EFFECTS OF THE INVENTION A stable heat ray reflective thin film was obtained by depositing a thin film having a composition modulation periodic structure in the film thickness direction by depositing one or more kinds of metal and metal oxide on a plastic film. . Further, this thin film could be produced by film winding vapor deposition, and high-speed film formation was possible.

[Brief description of drawings]

FIG. 1 shows an outline of an apparatus for producing a composition modulation film in Example 1.

FIG. 2 shows the results of measuring the composition distribution of Ag, Si, and O in the depth direction (film thickness direction) of the composition modulation film in Example 1.

3 shows the results of measuring the spectral characteristics of the composition-modulating film of Example 1. FIG.

[Simple explanation of symbols]

1,3: Film roll 2: Chill roll 4: Film 5: Protection plate 6: e-gun 7: SiO 8: Ag 9: Crucible

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teizo Harima 2-1-1 Katata, Otsu City, Shiga Prefecture Toyo Spinning Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu City, Shiga Prefecture Toyo Spinning Co., Ltd. Research Institute (56) Reference JP-A-2-289339 (JP, A) Special Table 4-504555 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/00-16/56 B32B 7/02 C03C 27/12

Claims (3)

(57) [Claims] 1. A thin film containing at least one kind of metal and at least one kind of metal oxide, and the film is formed in a film thickness direction.
80% composition of the metal is at most have a compositionally modulated periodic structure minimum of 20%, and the composition variation of at least two
A heat ray reflective thin film having the above periodic structure . 2. The heat ray reflective thin film according to claim 1, which is formed on a transparent substrate. 3. The heat ray reflective thin film according to claim 2, wherein the transparent substrate is a plastic film.