JP3028576B2 - Heat shielding glass - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shielding glass, and more particularly, to a heat-shielding glass having wear resistance that can be used in a single plate state and suitable for a window glass for automobiles and buildings. About the nature of the glass.

[Related Art] In recent years, a heat-shielding glass coated with a heat-shielding coating has been used for a window glass of a vehicle or a building in order to reduce sunlight energy flowing into the vehicle. Examples of such a heat-shielding glass include those utilizing a heat-reflecting property of a metal film such as Cu, Al and Ag, a metal nitride film such as titanium nitride and zirconium nitride, or a film of a high refractive index material. There is known a glass in which films of low refractive index materials are alternately laminated to reflect heat rays by an optical interference effect. Among them, those utilizing metal films such as Cu, Al and Ag overcome the problem of chemical durability, that is, corrosion due to an atmosphere containing acids and alkalis, and mechanical durability, that is, damage to the film due to clutches. Therefore, it is used as a laminated glass or laminated glass so that the coating is not exposed to the external environment. Also, even those using a metal nitride film that is said to have excellent durability as a heat ray shielding film,
The durability is not sufficient for use as single-pane glass.

Therefore, in order to improve the durability of the heat-shielding glass, research on coating a protective film with excellent durability on the uppermost layer is being actively conducted. As a high heat ray shielding glass,
As disclosed in JP-A-206333, a coating in which the uppermost layer of a coating is coated with a thick oxide film, for example, at least 1 μm or more of a SiO ₂ film has been proposed.

[Problem to be Solved by the Invention] When used in a state of being directly exposed to an external atmosphere such as glass for vehicles and buildings, the coating is required to have mechanical and chemical durability. It is important that the wear resistance is strong. In the case of coating the uppermost layer with a thick oxide film such as SiO ₂ of the above-described prior art, it is necessary to increase the thickness of the coating in order to have sufficient durability. There is a disadvantage that it requires a long time and the productivity is poor. Also above
The SiO ₂ film is coated by high-frequency sputtering using quartz glass as a target, or by DC sputtering using silicon as a target.Either method stabilizes the large plasma discharge required for coating large-area substrates. There is a problem that it is difficult to obtain. An object of the present invention is to solve the problems when manufacturing a heat-shielding glass having an oxide such as SiO ₂ as a protective film, and a machine such as a scratch for the protective film. An object of the present invention is to provide a heat ray shielding glass having a high mechanical strength and capable of stably coating the protective film on a large-area substrate.

[Means for Solving the Problems] According to the present invention, a transparent glass plate is coated with at least one heat ray shielding film, and silicon, carbon, nitrogen, and oxygen are coated on the heat ray shielding film. This is a heat ray shielding glass covered with a protective film made of. The protective film of the present invention can be represented by a chemical formula of SiCxNyOz, x,
The ratio of y and z is determined in consideration of required transparency, abrasion resistance and heat ray shielding property. That is, when importance is placed on transparency over all wavelengths in the visible region, x is set to a relatively small value, and y and z are increased. x is 1.22 or less,
The protective film having y of 0.7 or less and z of 0.4 or more has substantially no optical absorption in the visible region, and the refractive index of the film is 2.0 or less. It becomes a protective film of the heat ray shielding glass having low reflectivity and excellent durability. As a method of coating a protective film comprising silicon, carbon, nitrogen and oxygen according to the present invention, a sputtering method, an arc evaporation method, or a vacuum evaporation method performed in a reduced-pressure atmosphere is used. It is preferable to stably coat the film on the substrate. As an atmosphere gas for coating by the above method, any of a mixed gas of an inert gas and nitrogen and oxygen, or a mixed gas of nitrogen and oxygen can be used. The composition of the protective film is adjusted by changing the ratio of these gases. In an atmosphere of argon, nitrogen and oxygen, it is preferable to adjust the composition of the atmosphere so that at least nitrogen has a pressure of 0.066 Pa or more and accounts for 20% or more of the total pressure.
Further, the partial pressure of oxygen is preferably 1% or more of the total pressure.

When importance is placed on the heat ray shielding properties of the obtained glass, x can be set to a relatively large value so that the absorption in the visible region does not increase, while the values of y and z can be set relatively small. By setting z to 0.4 or less, the heat ray shielding performance can be increased without significantly lowering the transmittance in the visible region.

When coating the protective film of the present invention by sputtering,
It is preferable to use a reactive sputtering method performed in a reduced-pressure atmosphere containing at least nitrogen and oxygen using a target formed of a sintered body of silicon carbide. At this time, the use of a silicon carbide target containing free silicon improves the conductivity of the target and enables reactive sputtering by direct current, so that it can be applied to a large-sized insulating substrate such as a window glass. It is preferable for stable coating. Here, the weight ratio of silicon contained in silicon carbide is preferably 5 to 20% by weight,
15% by weight is more preferred. If less than 5% by weight,
It is not preferable because the conductivity of the target is not sufficient and glow discharge becomes unstable when performing high-speed DC sputtering applying a large current. On the other hand, if it is more than 20% by weight, the target becomes brittle and it becomes difficult to maintain stable discharge for a long time, which is not preferable.

The thickness of the protective film according to the present invention is desirably 5 nm or more. If the thickness is smaller than this, it becomes difficult to obtain practically necessary abrasion resistance. Conversely, coating with a thickness of 100 nm or more is not preferred because the abrasion resistance does not increase with the thickness and not only takes a long time to coat, but also may cause peeling of the film. For the above reasons, the economics of coating, considering the optical properties of the resulting glass, 20-80
More preferably, it is set in the range of nm.

There is no particular limitation on the coating having heat-ray shielding properties that is coated on the transparent glass plate. At least one selected from the group consisting of titanium nitride, zirconium nitride, hafnium nitride, and chromium nitride is preferably used. At this time, the thickness of the metal nitride film is preferably thin in order to increase the visible light transmittance, and is preferably large in order to increase the heat ray shielding property. The range of 2.5 to 7 nm is preferable for a glass having a high visible light transmittance. Further, the heat ray shielding film may be a film having a multilayer structure in which a film of a low refractive index material and a film of a high refractive index material are alternately laminated. The thickness of the film of the low refractive index material and the thickness of the film of the high refractive index material are determined to be approximately λ / 4 in terms of optical film thickness, where λ is the wavelength of the heat ray to be shielded.

Here, TiO ₂ , SnO ₂ , In
₂ O ₃ , ITO (indium oxide containing tin oxide), ZrO ₂ , Zn
A film having a high refractive index such as O or TaO ₂ can be exemplified, and a film such as SiO ₂ , Al ₂ O ₃ or MgF ₂ can be exemplified as the film of the low refractive index material.

The protective film according to the present invention has a high visible light transmittance based on a small light absorptivity and a small surface reflectivity based on a small refractive index. By selecting the thickness, a heat-shielding glass having a visible light transmittance of 70% or more suitable for a window glass of an automobile can be obtained.

As the transparent glass plate of the present invention, a colorless transparent float glass or a colored float glass such as bronze, gray, and blue can be used.

[Function] Since the protective film made of silicon, carbon, nitrogen and oxygen in the uppermost layer of the heat-shielding glass of the present invention is transparent in the visible region and has high wear strength, the heat-shielding property coated on the transparent substrate is high. Protects the coating from external forces such as abrasion and scratches, making it less prone to scratches.

Oxygen in the protective film lowers the refractive index of the film and improves the wear resistance of the film. This is considered to be due to the fact that the inclusion of oxygen increases the bonding of Si—O in the film and between the film and the substrate. Further, by adjusting the thickness and the refractive index of the protective film, the visible light reflectance of the heat ray shielding glass can be suppressed low.

[Examples] The present invention will be described in detail based on the following examples.
FIG. 1 is a partial cross-sectional view of the heat ray shielding glass of the present invention, 1 is a glass plate, 2 is a heat ray shielding film, and 3 is a protective film made of silicon, carbon, nitrogen and oxygen.

Example 1 In a DC magnetron sputtering apparatus provided with two cathodes, one cathode was provided with titanium metal, and the other cathode was provided with a silicon carbide sintered body containing about 18% by weight of free silicon as targets. did. The cleaned float glass plate having a thickness of 2.1 mm was put in a vacuum chamber of a sputtering apparatus, and evacuated to 5.3 × 10 ⁻⁴ Pa by a cryopump. Thereafter, nitrogen gas was introduced into the vacuum chamber at a flow rate of 50 sccm, and the pressure in the vacuum chamber was adjusted to 0.4 Pa. Then, power was supplied from a DC power supply to the metal titanium target to cause glow discharge. After setting to the current value of 1A,
The shutter above the titanium metal target was opened for 20 seconds, and the glass plate facing the titanium metal was coated with a titanium nitride film. The application of power to the target was stopped, the gas introduction was stopped, and the gas was again evacuated to 5.3 × 10 ^-4 Pa with a cryopump.Then, nitrogen gas was introduced into the vacuum tank at 47.5 sccm and oxygen gas at 2.5 sccm, and the vacuum was introduced. Set the pressure in the tank to 0.4
It was adjusted to Pa. Then, power was applied from a DC power supply to the silicon carbide target, and glow discharge was generated at a current value of 2 A. Thereafter, the shutter on the silicon carbide target was opened for 1 minute, and a protective film composed of silicon, carbon, nitrogen and oxygen and represented by the chemical formula of SiCxNyOz was further coated on the titanium nitride film.

The glass sample obtained in this way is placed on the glass
A glass having a heat ray shielding property coated with a titanium nitride film having a thickness of 5 nm and a protective film made of silicon, carbon, nitrogen and oxygen having a thickness of about 75 nm, and having a visible light transmittance of 7
The visible light reflectance was 2.3% for light incident from the glass surface, and the solar radiation transmittance was 65.3%. The coating of this glass sample was subjected to a wear resistance test using a commercially available Taber abrasion tester. A load of 500 g was applied to each of the two wear wheels of No. CS10F, and 1000 rotations of wear were applied to the coating at a rotation speed of 60 rpm. The haze ratio was measured.
Only a 0.1% change was observed, and scars were hardly noticeable.

Using the same sputtering apparatus, a monolayer film of a compound consisting of silicon, carbon, nitrogen and oxygen of about 75 nm was attached on a glass substrate, and X-ray diffraction measurement and electron microscopic observation were performed. According to the X-ray diffraction, diffraction peaks based on the crystals of the protective film were not observed except for the broad peak based on the glass plate, and it was found that the obtained protective film was amorphous. On the other hand, electron microscopic observation revealed that the protective film was dense and no columnar structure was observed, and that the surface of the film was extremely smooth.

Example 2 Using a method similar to that of Example 1, the protective film composed of silicon, carbon, nitrogen and oxygen was coated on the glass plate only by changing the flow rate of the gas introduced into the vacuum layer. . The abrasion resistance of the obtained coating was measured, and the protective film Si
Table 1 shows the results of measuring the optical constants of CxNyOz. First
From the table, the change in visible light transmittance before and after the wear test is 1.23%
The following values were small, and the haze ratio of the coating after the test was as small as about 2.1%. It was found that the protective film SiCxNyOz had excellent wear resistance.

Example 3 The same as Example 1 except that the thickness of the protective film composed of silicon, carbon, nitrogen, and oxygen and represented by the chemical formula of SiCxNyOz was changed to 10 nm by changing the current applied to the silicon carbide target and the sputtering time. Thus, a heat ray shielding glass was manufactured. The coating of this glass sample was subjected to a wear resistance test in the same manner as in Example 1 using a commercially available Taber abrasion tester. No.CS10F for each of the two wear wheels
After applying a load of 500 g and applying abrasion of 1000 rotations to the coating at a rotation speed of 60 rpm, when the haze ratio was measured, only 0.
Only a 1% change was observed, and scars were hardly noticeable.

Comparative Example 1 Using the same method as in Example 1, the protective film composed of silicon, carbon and oxygen was coated on the glass plate only by changing the ratio of the flow rate of the gas introduced into the vacuum chamber. Table 2 shows the results of the abrasion resistance test of the obtained film which can be expressed as SiCxOz by the chemical formula consisting of silicon, carbon and oxygen in the same manner as in Example 1, and the optical constants were measured. Second
As shown in the table, the visible light transmittance was 10% as a result of the abrasion test.
The above changes and the haze ratio was 3-4%.

Comparative Example 2 2.1 mm cleaned using the same sputtering apparatus as in Example 1.
A 75-nm thick film represented by the chemical formula of SiCx was coated on a thick glass plate by sputtering in an atmosphere in which only argon was introduced into a vacuum chamber. This film had an extremely high refractive index of 3.79, and exhibited light absorption in the visible region. The haze ratio after the wear test under the same conditions was a large value of 4.0%.

Comparative Example 3 2.1 mm cleaned using the same sputtering apparatus as in Example 1.
On a thick glass plate, a film represented by the chemical formula of SiCxNy was coated to a thickness of 75 nm by sputtering in an atmosphere in which only nitrogen gas was introduced into a vacuum layer. The refractive index of this coating was 2.04.
The haze ratio after the abrasion resistance test performed under the same conditions as in Example 1 was
It was 3.1%.

As described above, it can be seen that the protective film according to the present invention composed of silicon, carbon, nitrogen, and oxygen has excellent wear resistance.

[Effect of the Invention] Since the outermost layer of the heat ray shielding glass of the present invention, which is in contact with air, has a protective film made of silicon, carbon, nitrogen and oxygen and has excellent wear resistance, it can be used in a state where it is directly exposed to the outside air. It is hard to be scratched by scratches. Therefore, it can be used in the form of a single plate without being made into a multi-layer glass or a laminated glass as an automobile window glass or a building window glass.

Further, since the protective film of the present invention can be coated by a direct current sputtering method, it can be stably coated on a large substrate.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of the heat ray shielding glass of the present invention. 1 ... a glass plate, 2 ... a heat ray shielding film, 3 ... a protective film made of silicon, carbon, nitrogen and oxygen.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03C 17/00-17/44 C23C 14/06

Claims (5)

(57) [Claims] 1. A transparent glass plate is coated with at least one heat ray shielding film, and a protective film made of silicon, carbon, nitrogen and oxygen is coated on the heat ray shielding film. Heat shielding glass. 2. The heat ray according to claim 1, wherein the heat ray shielding film is at least one selected from the group consisting of titanium nitride, zirconium nitride, hafnium nitride, and chromium nitride. Shielding glass. 3. A heat-shielding film according to claim 1, wherein said heat-shielding film has a multilayer structure in which films made of a low-refractive-index material and films made of a high-refractive-index material are alternately laminated. Item 3. The heat ray shielding glass according to Item 1 or 2. 4. The heat ray shielding glass according to claim 1, wherein said protective film has a thickness of 5 nm or more and 100 nm or less. 5. The method according to claim 1, wherein said protective film is coated by direct current reactive sputtering in a reduced-pressure atmosphere using a target of silicon carbide containing free silicon. Item 5. The heat ray shielding glass according to any one of Items 4 to 4.