JP2906524B2 - Infrared reflective article - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an infrared reflective article having high transmittance and improved durability.

[Prior Art] Conventionally, there are two types of infrared reflective articles known as a solar control type which is mainly used for reducing a cooling load, and a type which is mainly used for reducing a heating load. There is a type called a heat mirror used. The minimum required properties of the latter are high transmittance in the visible region and sufficiently high reflectance in the infrared region. Conventionally, as this type of heat ray reflective glass, there are three types of (1) a thin film of about 100 ° of metal, (2) a film of a doped oxide semiconductor, and (3) a three-layer structure of dielectric / metal / dielectric. What was formed on glass was known.

Of these, the type (1) has a disadvantage in that the thickness of the metal film must be increased in order to sufficiently increase the reflectance in the infrared region, and the transmittance in the visible region decreases. Further, specific materials of the type (2) include SnO ₂ , In ₂ O ₃
However, in this type, the film thickness needs to be 5000 mm or more in order to sufficiently increase the reflectance in the infrared region, which is disadvantageous in cost.

On the other hand, in the type (3), since the dielectric film sandwiching the metal film acts as an anti-reflection film, a sufficiently high reflectance in the infrared region and a high transmittance in the visible region as a whole are 1000%.
で き る Can be realized with the following film thickness. As a specific material, a configuration in which silver is sandwiched by a dielectric film in order to sufficiently bring out the characteristics of the type (3) is widely used (Japanese Patent Publication No. 47-6315). In addition, the type (3) generally has a U-shaped spectral reflection characteristic in the visible region, and can produce only a violet-based color tone as a reflection color. By using five layers of body / Ag / dielectric / Ag / dielectric, the color tone variation can be widened (Japanese Patent Laid-Open No. 63-239043).

However, in the case of the type (3), the durability of the Ag layer, which is a metal film, is extremely poor.
Can often agglomerate and their properties can be severely impaired. For this reason, the type of (3) cannot be used as a single plate, and is generally used in a multilayered form. However, due to the low durability of Ag, it is necessary to shorten the storage period until the layer is formed, or to severely restrict the storage state. In addition, there is a possibility that a problem such as generation of pinholes may occur during transportation of the product in the form of a single plate to a place where the product is laminated.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and has a very high reflectance in an infrared region and a sufficiently high reflectance in a visible region. An object of the present invention is to provide an infrared-reflective article that has a transmittance and is not easily deteriorated during storage in a single-plate state, or during transportation to a place where multiple layers are formed or combined.

[Means for Solving the Problems] The present invention has been made to solve the above-described problems, and a total of transparent oxide layers and silver layers alternately laminated on a transparent substrate in this order ( A (2n + 1) layer (n ≧ 1) coating is formed, the outermost layer of the (2n + 1) layer coating is a transparent oxide layer of zinc oxide (ZnO), and on the outermost layer is boron and silicon. At least one of the group consisting of titanium, zirconium,
An infrared reflective article provided with an amorphous oxide layer containing at least one member selected from the group consisting of hafnium, tin, tantalum, and indium.

FIG. 1 shows a cross-sectional view of an example of the infrared reflective article of the present invention.

As the transparent substrate 1 in the present invention, glass, plastic, PET or the like can be used. As the transparent oxide in the present invention, a material having a relatively large refractive index such as TiO ₂ , ZrO ₂ , In ₂ O ₃ , SnO ₂ , ZnO, Ta ₂ O ₅ and a mixture thereof, for example, n = 1.7 to 2.5 A material having a refractive index is used.

As a film configuration in the present invention, a transparent oxide layer 2 is used as a first layer in contact with a transparent substrate 1, and a second layer is a silver layer 3, and a third layer is a transparent oxide layer 2 in an alternating manner. In the (2n + 1) -th layer, which is the uppermost layer, zinc oxide (ZnO) is always used as the transparent oxide layer 2, and an amorphous layer is formed on the (2n + 1) -th transparent oxide layer 2. The oxide layer 4 is coated as a protective layer. The value of n in the (2n + 1) layer is considered to be 3 or less in order to maintain the visible light transmittance at 70% or more.

The thickness range of the transparent oxide layer 2 in a preferred embodiment of the present invention varies slightly depending on the material used, but is roughly as follows. That is, the first layer is 200 to 600 °, and the uppermost (2n + 1) layer is
The thickness is 100 to 400 mm, and the other layers are 400 to 1200 mm.

These film thickness ranges are set in order to realize high transmittance in the visible region. If the film thickness deviates from this range, the film deviates from the interference condition, the antireflection effect is not exhibited, and the visible light transmission is not achieved. The rate drops. Also, the transparent oxide layer 2
Although it is desirable from the viewpoint of production that each layer is composed of the same material, the present invention is not limited to this, and any one layer may be composed of a material different from the others. Further, all the layers may be made of different materials.

On the other hand, the thickness of the silver layer 3 is preferably 110 ° or less in order to secure a sufficient transmittance in the visible region and to obtain a sufficiently large variable range of the reflection color tone by adjusting the thickness. That is, as the thickness of the silver layer increases, the transmittance in the visible region decreases, and it becomes difficult to secure a value of 70% or more. On the other hand, when the film thickness is reduced, silver becomes an island-shaped film, and predetermined characteristics cannot be obtained or the state is easily deteriorated. Therefore, the thickness of the silver layer is preferably about 60 ° or more. .

The amorphous oxide layer 4 used in the present invention includes at least one selected from the group consisting of titanium, zirconium, hafnium, tin, tantalum and indium, and at least one selected from the group consisting of boron and silicon. It consists of oxide.

The composition of the amorphous oxide 4 is such that an oxide of titanium, zirconium, hafnium, tin, tantalum, indium, boron, or silicon is used to make the film amorphous and improve scratch resistance and reliability. To TiO ₂ , ZrO ₂ , HfO ₂ , Sn
When expressed as O ₂ , Ta ₂ O ₅ , In ₂ O ₃ , B ₂ O ₃ , SiO ₂ , TiO ₂ , Zr
The total number of moles of the oxide selected from O ₂ , HfO ₂ , SnO ₂ , Ta ₂ O ₅ and In ₂ O ₃ is 100 parts, and the sum of the oxides selected from B ₂ O ₃ and SiO ₂ is 100 parts. Is at least 5 parts by mole, preferably 10 parts
Parts or more, especially 20 parts or more.

Further, in the case of B ₂ O ₃ , if it is too much, the chemical durability and reliability are lowered, so that TiO ₂ , ZrO ₂ , Hf
The total mole number of oxides selected from O ₂ , SnO ₂ , Ta ₂ O ₅ and In ₂ O ₃ is 200 parts or less, preferably 100 parts or less, preferably 100 parts by mole
100 parts or less, especially 50 parts or less is good.

In the case of SiO ₂ , if the amount is too large, the durability against alkali decreases, so the total number of moles of oxides selected from TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , Ta ₂ O ₅ and In ₂ O ₃ 1900 parts or less in molar ratio to 100 parts, preferably 900 parts or less, especially 400 parts
Or less.

Table 1 shows properties of various amorphous oxide groups that are optimal for the amorphous oxide layer 4 of the present invention. Films were formed by reactive sputtering using targets having the compositions shown in the table. Note that Sample 1, Sample 2, and Sample 17 are examples of crystalline oxide films.

 The crystallinity was observed by thin film X-ray diffraction.

The abrasion resistance is the result of a rubbing test with a sand eraser. ○ indicates that the scratch was hardly formed, and X indicates that the scratch was easily generated.

Abrasion resistance is measured by Taber test (wear theory CS-10F, weight 500
g, 1000 rotations), and those with a haze of 4% or less are indicated by ○, and those with a haze of more than 4% are indicated by x.

The heat resistance is the result of immersion in 0.1N H ₂ SO ₄ for 240 hours. The change rate of T _V (visible light transmittance) and R _V (visible light reflected light) before immersion is within 1%. 、, 1 to 4% are indicated by Δ, and the film dissolved and disappeared is indicated by X.

Alkali resistance is a result of the immersion for 240 hours in a NaOH of 0.1 N, shows T _V, ○ what change rate for the previous immersion R _V is within 1%, those films had dissolved as ×.

In the boiling test, after immersion in water at 100 ° C. under 1 atm for 2 hours, when the rate of change of T _V and R _V before immersion is within 1%, ○ is shown, and when more than 1%, X is shown.

As is clear from Table 1, the ZrB _x O _y film tends to form a crystalline film when the amount of B in the film is small, and tends to form an amorphous film when the amount of B is large. A crystalline film is poor in abrasion resistance and abrasion resistance, whereas an amorphous film is excellent. This is probably because the amorphous film has a smooth surface. Therefore, the ZrB _x O _y film (the atomic ratio of B to Zr in the film, x> 0.10) has excellent scratch resistance and abrasion resistance.
Since the B ₂ O ₃ film is hygroscopic and absorbs and dissolves moisture in the air, it is preferable that x ≦ 3 in the ZrB _x O _y film.

The atomic ratio of O (oxygen) to Zr in the ZrB _x O _y film is not particularly limited, but if it is too large, the film structure becomes coarse and the film becomes loose, and if too small, the film becomes metallic and the transmittance becomes low. Therefore, the amount is preferably such that ZrO ₂ and B ₂ O ₃ are a composite system since the film tends to decrease and the scratch resistance of the film tends to decrease. That is, when the composite oxide is expressed as ZrO ₂ + xBO _1.5 ,
When B is contained at an atomic ratio of x to Zr, y = 2 + 1.
It is preferably about 5x.

Also, from Table 1, as the amount of B in the ZrB _x O _y film increases,
It can be seen that the refractive index of the film tends to decrease. FIG. 2A shows the relationship between the film composition and the refractive index n. B in the film
Increases, the refractive index n decreases from about 2.0 to about 1.5.

Therefore, a ZrB _x O _y film with 0.10 <x ≦ 3 and 2 <y ≦ 6.5 has good scratch resistance and abrasion resistance, and the refractive index can be freely selected depending on the amount of B. It is a suitable amorphous oxide film.

Furthermore, as shown in Table 1, as the content of B in the film increases, the acid resistance and alkali resistance tend to deteriorate. When x ≧ 2.3, the acid resistance deteriorates, and when x> 4, the alkali resistance decreases and the boiling test shows deterioration. Therefore, a protective film of ZrB _x O _y (x <2.3) is preferred for applications that are used while exposed in air.

As described above, by adding B ₂ O ₃ to the ZrO ₂ film, the film becomes amorphous and the surface becomes smooth. It is considered that the abrasion resistance and the abrasion resistance are improved by this. Also, B
Can adjust the refractive index. Furthermore, compared to ZrO ₂ film,
Since the internal stress is small, it is advantageous in terms of adhesion to a film in contact therewith. This is particularly advantageous when forming a thick film.

Next, the ZrSi _z O _y film is an amorphous film and has high scratch resistance and high abrasion resistance. Regarding the refractive index,
It changes between ZrO ₂ (n = 2.15) and SiO ₂ (n = 1.46) depending on the composition ratio (see FIG. 2 (b)). More specifically, in the ZrSi _z O _y film, it is preferable that 0.05 ≦ z (atomic ratio of Si to Zr in the film) ≦ 19. When z <0.05, the film does not become amorphous, and sufficient physical durability cannot be obtained. When z> 19, the alkali resistance is deteriorated. Y (atomic ratio of O to Zr in the ZrSi _z O _y film) is ZrB
for the same reason as that described for _x O _y film, when the Si is contained z in atomic ratio to Zr, it is preferably about y = 2 + 2z.

Further, a ZrB _x Si _z O _y film is also a film suitable for the purpose of the present invention. When the atomic ratio x of B to Zr, the atomic ratio z of Si, and the atomic ratio y of O in such a film are x + z ≧ 0.05, the film becomes amorphous, and the film has high scratch resistance and abrasion resistance. Is preferable.

Further, if x + z ≦ 19, the alkali resistance is also good. Therefore, in the ZrB _x Si _z O _y film, it is preferable that 0.05 ≦ x + z ≦ 19. However, as described above, since B ₂ O ₃ is hygroscopic and absorbs and dissolves moisture in the air, it is better not to contain too much in the ZrB _x Si _z O _y film.

Specifically, in the film, ZrO ₂ <25 mol% and SiO ₂
If B ₂ O ₃ is contained in such an amount that the remaining amount becomes B ₂ O ₃ at <25 mol%, the chemical durability becomes insufficient. That is, ZrB _x Si _z O
_If Zr: B: Si (atomic ratio) in the _y film is 1: x: z, 1 / (1+
x + z) <0.25 and Z / (1 + x + z) <0.25, that is, the composition of x + z-3> 0 and x-3z + 1> 0 has poor chemical durability.

y is considered to be a composite system of ZrO ₂ + B ₂ O ₃ + SiO ₂ for the same reason as described in the case of ZrB _x O _y , and y is 2 + 1.
It is preferable to be about 5x + 2z. Therefore, almost 2 <y <
It is preferably about 40. The higher the content of B or Si, the lower the refractive index of the ZrB _x Si _z O _y film. FIG. 2 (c) shows an example of the ZrB _i Si _z O _y film.

Metals other than Zr, namely, titanium, hafnium, tin,
An oxide containing tantalum, indium, and at least one of boron and silicon also becomes amorphous, and sufficient scratch resistance and abrasion resistance can be obtained. An example of the TiSi _z O _y film is shown as Sample 16 in Table 1.

As described above, in the films of ZrB _x O _y system, ZrB _x Si _z O _y system, etc., the amounts of B and Si added may be adjusted so as to have the necessary refractive index as the above-mentioned protective film.

In the present invention, the refractive index n of the amorphous oxide film depends on the film thickness, but in order to maintain the interference condition and obtain a visible light transmittance of 70% or more, n should be 1.6 or more and 2.1 or less. preferable.

From Table 1 and FIGS. 2 (a) to 2 (d), the composition required for a desired refractive index can be understood. For example, for ZrB _x O _y type film, 0.1 ≦ x in order to n ≦ 2.1, but preferable to be x ≦ 8 in order to n ≧ 1.6, in terms of scientific durability as described above And x ≦ 3 is preferable. Also, ZrSi _z O _y
For the system film, 0.1 ≦ z, n ≧
In order to make it 1.6, it is preferable that z ≦ 4.

When the amorphous oxide layer in the present invention is replaced with ZnO, which is the (2n + 1) -th transparent oxide, and is brought into direct contact with the silver layer, the durability is not as high as when the transparent oxide is interposed. . Although the cause is not clear at present, it is considered that boron and silver in the amorphous oxide cause some side reaction. Therefore, it is preferable that a transparent oxide layer is interposed between the amorphous oxide layer and the silver layer.

The thickness of the amorphous oxide layer 4 in the present invention needs to be balanced with the transparent oxide layer in order to realize a high transmittance in the visible region, but is preferably 100Å to 500Å, particularly 100Å to 400400.
Å, is excellent. If the thickness is less than this, the film cannot sufficiently serve as a protective layer. Also, depending on the refractive index, if the thickness is more than 70 nm, the interference condition is maintained, and % Is difficult to achieve.

The method for forming the infrared reflective article of the present invention is not particularly limited, and a vacuum deposition method, an ion plating method, a sputtering method, or the like can be employed. When a large area coating is required, a reactive sputtering method which is excellent in uniformity is preferable. In addition, it is particularly preferable that the infrared reflective article of the present invention be prepared in the same vacuum chamber from the first transparent oxide layer to the amorphous oxide layer. The effect is not hindered even if the amorphous oxide layer is put into the air once before coating, and the amorphous oxide layer is formed later.

In addition, the infrared reflective article of the present invention has a boundary with a thickness that does not change its optical characteristics at the interface with the substrate or the interface of each layer for the purpose of further improving the adhesive force and durability. Layers may be inserted.

Applications of the present invention include low emissivity glass in which another substrate is multi-layered through an air hollow layer with the side on which the film is formed inside, a door for a frozen showcase, a film, and the like. Laminated glass for automobiles, buildings, and the like, which are bonded together with an intermediate film on the side on which the is formed.

Since the infrared reflective article of the present invention has a low sheet resistance value because it has a silver layer, it can also block electromagnetic waves,
It can also be used for electromagnetic wave shielding windows and partitions in intelligent buildings and the like.

[Action] Although the protection mechanism by the amorphous oxide layer in the present invention is not always clear, it is considered important that the film is made amorphous by adding silicon or boron which is a glass component. It is considered that the biggest factor of the deterioration in the infrared reflective article in which the transparent oxide layer and the silver layer are alternately laminated is oxidation of silver. In order for the oxidation reaction to take place,
Oxygen and moisture need to be diffused, and if the film is crystalline, the grain boundary serves as a diffusion path, and the reaction easily occurs. Therefore, it is considered that the durability is improved by using an amorphous layer having no crystal grain boundaries as a protective layer as a diffusion barrier.

[Example] Example 1 Metal Zn and metal A were placed on the cathode of a magnetron DC sputtering apparatus.
g, and a target of Zr-B (Zr: B = 7: 3 (atomic ratio)) were set. After washing and drying the 2 mm thick soda lime glass substrate by a method such as polishing, put it in a vacuum chamber,
The oil was evacuated to 1 × 10 ⁻⁵ Torr or less by an oil diffusion pump. At this time, the substrate was not heated. Next, O ₂ gas was introduced into the vacuum system, and the pressure was adjusted to 3.0 × 10 ⁻³ Torr. In this state, a power of 5.2 W / cm ² was applied to the metal Zn target to form a ZnO film having a thickness of 400 mm.

Next, the atmosphere in the vacuum system was completely replaced with 100% pure Ar gas, and the pressure was adjusted to 3.5 × 10 ⁻³ Torr.
In this state, a power of 0.8 W / cm ² was applied to the metal Ag target to form an Ag film of 150 mm.

Next, the atmosphere in the vacuum system is returned to 100% O ₂ gas again,
At a pressure of 3.0 × 10 ⁻³ Torr, a ZnO film was formed to a thickness of 200 mm on the air side. Finally, the atmosphere in the vacuum system is changed to a mixed gas of Ar / O ₂ = 7/3 (volume ratio), and a power of 7.8 W / cm ² is applied to the Zr-B target at a pressure of 3.5 × 10 ⁻³ Torr. Then, a ZrB _x O _y film was formed as a protective layer to form a film of 200 mm.

The sample thus obtained had a visible light transmittance of 75.9%. When this sample was left in an atmosphere of 50 ° C. and 95% RH for 46 hours, the visible light transmittance changed to 77.4%, but there was no change as a result of visual observation. When a fingerprint was intentionally applied to the surface of the film and left in an atmosphere of 50 ° C. and 95% RH for 19 hours, a slight small pinhole was observed in the fingerprint portion.

Example 2 In the same procedure as in Example 1, a ZnO film was formed as
Å, Ag film as the second layer is 100Å, ZnO film as the third layer is 8080
After 0Å film formation, and 100Å film formation 100Å, the ZnO film as the fifth layer an Ag film as the fourth layer again, manufacturing a ZrB _x O _y film as 300Å protective layer in the same manner as in Example 1 thereon Filmed.

The sample thus obtained had a visible light transmittance of 80.2%. This sample had a visible light transmittance of 80.1% after being left in an atmosphere of 50 ° C. and 95% RH for 53 hours, and there was no change when visually observed. In addition, the visible light transmittance after leaving the sample in the weather meter for 36 hours was 78.6%. Even when visually observed, only a very thin haze was observed at the end, and there was almost no change in the center. .

Comparative Example 1 In the same procedure as in Example 1, a ZnO film was formed as
Å, Ag film 150 as the second layer, ZnO film 40 as the third layer
A 0 ° film was formed, and no protective film was provided thereon.

The sample thus obtained had a visible light transmittance of 78.4%. After this sample was left in a 50 ° C., 95% RH atmosphere for 46 hours, the visible light transmittance was 75.4%, and the change amount was not so large, but when visually observed, a pinhole was observed on the entire surface. . When a fingerprint was intentionally applied to the surface of the film and allowed to stand in an atmosphere of 50 ° C. and 95% RH for 19 hours, the fingerprint portion was completely discolored and was in a haze state.

Comparative Example 2 A metal Sn was set as a target instead of metal Zn, and a SnO ₂ film was formed as a first layer by the same procedure as in Example 1.
0 °, Ag film as the second layer 110 °, SnO ₂ film as the third layer
A 400Å film was formed. As in Comparative Example 1, no protective layer was provided. The conditions for forming the SnO ₂ film were as follows: the pressure was 3.0 × 10 ⁻³ Torr and the applied power was 4.8 W / cm ² in a 100% pure O ₂ gas atmosphere.

The sample thus obtained had a visible light transmittance of 84.7%. After this sample was left in an atmosphere of 50 ° C. and 95% RH for 53 hours, the visible light transmittance was 73.6%, scale-like haze occurred on the entire surface, and there were many pinholes. When a fingerprint was intentionally applied to the surface of the film and allowed to stand for 19 hours, a considerably large pinhole was generated in the fingerprint portion. The visible light transmittance of the same sample after standing in a weather meter for 36 hours was 82.6.
%, The whole surface was in a thin haze state when visually observed.

[Effects of the Invention] As described above, in the present invention, by overcoating the amorphous oxide layer, the film functions as a barrier layer for preventing the Ag film from deteriorating due to oxidation, and the transparent oxide layer And a silver layer are alternately laminated to improve the durability of an infrared reflective article as a single plate.

Further, in the present invention, by overcoating an amorphous oxide layer containing boron and silicon, the surface smoothness is improved and the scratch resistance is improved. In addition, it suppresses the penetration of moisture, acid, alkali, etc. into the interior due to the disappearance of the grain boundaries, and in the case of Ag that is easily migrated like Ag, it diffuses to the surface through the grain boundaries and deteriorates. Is preventing. Thereby, an infrared reflective article having excellent durability can be obtained.

For this reason, the effect that the weather resistance of a veneer is improved and that it is less likely to be damaged than a normal product is also recognized.

The refractive index can be adjusted in a wide range from 1.5 to 2.1 by appropriately selecting the amount of boron, silicon, or a combination of both, so that the protective film can have the function of an optical film. As a result, the degree of freedom in optical design is increased and the structure of the film is simplified, which greatly contributes to improving productivity.

Further, it is considered that the effect of this amorphous oxide layer can be further enhanced by improving the durability of Ag by adding an additive or the like to Ag.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of the infrared reflective article according to the present invention. FIG. 2A shows the content of B in the ZrB _x O _y film and the refractive index n of the film.
FIG. 2 (b) shows the relationship between the Si content in the ZrSi _z O _y film and the refractive index n, and FIG. 2 (c) shows the relationship between the Si content in the ZrB ₁ Si _z O _y film. FIG. 2D shows the relationship between the content and the refractive index n.
FIG. 3 is a diagram showing the relationship between the content of Si in the Si _z O _y film and the refractive index n, respectively. 1: transparent substrate 2: transparent oxide layer 3: silver layer 4: amorphous oxide layer

Claims (2)

(57) [Claims] 1. A coating comprising a total of (2n + 1) layers (n ≧ 1) in which a transparent oxide layer and a silver layer are alternately laminated in this order on a transparent substrate, and a coating comprising such (2n + 1) layers Is a transparent oxide layer made of zinc oxide (ZnO), and on the outermost layer is made of at least one of the group consisting of boron and silicon and titanium, zirconium, hafnium, tin, tantalum and indium. An infrared-reflective article provided with an amorphous oxide layer containing at least one member of the group. 2. The thickness of the amorphous oxide layer is 100 to 400 mm.
The infrared reflective article according to claim 1, wherein: