JP2762609B2 - Near infrared shielding glass - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near-infrared blocking glass having a small near-infrared transmittance, and particularly to a near-infrared blocking glass having a large visible light transmittance.

[Related Art] In recent years, heat ray absorbing glass and heat ray reflecting glass have been widely used for buildings, automobiles, vehicles, and the like for the purpose of reducing the cooling load or the feeling of heat and sun rays. Here, the heat ray absorbing glass is a glass plate having a normal soda lime composition in which coloring components such as iron oxide, cobalt oxide, nickel oxide, and selenium are included in the glass composition. The absorption prevents solar radiation energy from flowing into buildings or into automobiles and vehicles. Heat ray reflective glass is usually an oxide having a high refractive index such as iron,
Forming a thin film of oxide such as cobalt, chromium, titanium, etc. and using the light interference effect to increase the surface reflectivity and reflect solar energy to prevent the inflow of solar radiation energy into buildings or automobiles / vehicles Things.

Furthermore, in recent years, with the development of a thin film forming technique by a sputtering method, a heat ray reflective glass utilizing reflection / absorption of a metal thin film such as titanium, nickel, and stainless steel or a nitride thin film thereof has been widely used.

By the way, solar radiation energy is generally composed of about 4% of ultraviolet rays, about 50% of visible rays, and about 46% of near-infrared rays in energy composition. Therefore, considering that the heat-absorbing glass and the heat-reflecting glass mainly block the solar radiation energy by absorption or reflection in the visible light region, the effect of blocking the solar radiation energy by these glasses is the visible light transmittance. There was a limit from the point. In other words, in the case of buildings, the more the solar energy blocking effect is increased, the darker the interior and the less comfortable it is, and also from the viewpoint of energy economy, there is a problem that the lighting energy in the building will increase. Was. On the other hand, in the case of automobiles and vehicles, if the visible light transmittance is small, it is obvious that the characteristics of products are significantly impaired in terms of see-through safety.

Therefore, there is a strong demand for a bright heat ray reflective glass that blocks solar energy in the near-infrared region (that is, has a low sunlight transmittance Tg), but has a high visible light transmittance (T _L ), that is, a so-called near-infrared blocking glass. Was.

When these materials are actually used, the strength of the glass is often a problem. That is, first, in the case of architectural use, of the solar radiation energy, the energy absorbed by the film (and glass) becomes heat to increase the temperature and generate distortion due to thermal expansion, which causes so-called thermal cracking. On the other hand, in the case of automobiles and vehicles, it is clear that the glass must be laminated or otherwise strengthened to ensure safety in the event of a collision. Especially when it is necessary to open and close the window by raising and lowering the glass like a side window of a car,
Laminated glass is not suitable and single-pane tempered glass is required. In consideration of the uniformity of application, it is more convenient to strengthen and bend the glass after applying the film.

Some attempts have been made to provide a glass that selectively absorbs or reflects near-infrared light from such a background. For example, there is a method utilizing absorption in a near-infrared region, which is considered to be caused by a valence transition of a transition metal oxide such as tungsten oxide or molybdenum oxide, which is disclosed in JP-A-60-235746. Alternatively, as another method, a laminate in which one or both surfaces of a metal thin film layer of gold and silver proposed in Japanese Patent Publication No. 59-44993 is covered with a transparent high refractive index layer, for example, TiO ₂ / Ag / TiO ₂ , Bi ₂ O ₃ / Au / Bi ₂ O ₃ and ZnS / Ag / ZnS.

However, the transition metal oxide has a property of being slightly soluble in water, and has a limitation that it can be used only in a form such as a laminated glass or a multi-layer glass that can completely prevent the penetration of moisture. Furthermore, the heat treatment significantly reduces the near-infrared ray blocking effect, so that bending and strengthening cannot be performed.

On the other hand, even in a laminated body using a thin metal film of gold and silver, various environmental conditions such as heat, light, moisture, and gas cause deterioration of the laminated body. -There was a problem that the life was uneasy.

A description of the application of a film made of a Sn—Sb oxide as a resistor has been found in US Pat. No. 2,564,708. However, there is no description about the visible light transmittance in this patent content, and there is no description about conditions related to strengthening after film formation.

For this reason, the present inventors can most effectively use a mixed film of an oxide of Sn and Sb among thin film materials meeting the purpose of such a highly durable and high-performance near-infrared shielding glass, It was found that when the content ratio (% by weight) of Sb was ₂ to 20% in terms of Sb ₂ O ₃ , the visible light transmittance was high and effective.

Furthermore, in this case, due to the tempering treatment, countless cracks are sometimes generated in the coating due to the difference in the coefficient of thermal expansion between the glass and the coating at the time of air cooling, which is a problem particularly in providing high-intensity near-infrared shielding glass. Was. Neither the film formation temperature nor the Sb composition for maintaining high transmittance in the visible light region was clear.

[Problems to be Solved by the Invention] The present invention has been made in view of the problems of such near-infrared shielding glass,
It is an object of the present invention to provide a highly durable, high-performance, high-strength, near-infrared shielding glass which has been subjected to a tempering treatment and which can be used even under a single glass condition.

[Means for Solving the Problem] The near-infrared blocking glass of the present invention is characterized in that the glass is coated with a film having near-infrared absorption performance, and then the glass is remarkably enhanced by a tempering treatment.

In this case, the coating having near infrared absorption performance is Sn and
A mixture of Sb oxides (hereinafter referred to as Sn-Sb oxide film), wherein the content (% by weight) of Sb in the mixture coating is 2 to 20% in terms of Sb ₂ O ₃ Desired. Sb
When the content of Sb ₂ O ₃ (% by weight) is 2% or less,
Poor near-infrared blocking performance, while exceeding this upper limit Sb
Even if the mixing ratio is increased, the _TL sharply decreases, and the acid resistance and heat resistance gradually decrease. The composition in the film was determined by plasma emission analysis and fluorescent X-ray analysis (PW14 manufactured by Phillips).
(Type 00).

By the way, as a method of forming such a Sn-Sb oxide film, a solution containing a compound of Sn and Sb, or a gas containing a vapor or a powder thereof, is brought into contact with a high-temperature glass to form a Sn-Sb film on the glass surface. An oxide film is preferably used. Specifically, monobutyltin trichloride (C ₄ H ₉ SnCl ₃ ) is used as the Sn material, and antimony trichloride (SbC
l ₃₎ or SbCl ₅ a method of blowing and atomizing the glass heated to 500 ° C. or higher are dissolved in a suitable solvent can be considered. Note that a combination of a solvent to which Sb ₂ O ₅ and HCl are added as an antimony raw material may be used. Further, in order to adjust the color tone and optical characteristics of the obtained coating, a metal salt such as V or Bi may be dissolved in the above-mentioned mixed solution, and these metal oxides may be contained in the coating. In addition, as a spraying method, a liquid in which each component is mixed in advance may be sprayed as fine droplets,
Each component may be separately sprayed and reacted simultaneously as droplets.

In the Sn—Sb mixed oxide film thus obtained, an absorption peak is observed in the near-infrared region, which is considered to be caused by the transition between trivalent and pentavalent Sb. The rate is expected to decrease.

As described above, in the present invention, a glass having a high visible light transmittance and a large near-infrared absorption can be provided by selecting the glass composition, the element ratio in the Sn-Sb oxide film, and the film temperature. When the glass of (1) is put to practical use, the glass is often subjected to a tempering treatment to increase the strength of the glass. There are various methods of tempering, but the so-called air-cooling tempering method, which raises the temperature of the glass above the softening temperature and then solidifies only the surface to generate surface compressive stress, is economically or moldable. This is considered the optimal method. In this regard, the Sn-S of the present invention
It became clear that the excellent optical properties of the b-oxide film did not change at all even after such treatment. However, the coefficient of thermal expansion of soda-lime glass is as large as about 1 × 10 ⁻⁵ ° C. ⁻¹ , while the coefficient of thermal expansion of the oxide is remarkably 4 × 10 ⁻⁶ ° C. ⁻¹ . For this reason
If the thickness of the Sn—Sb oxide film is too large, cracks are generated in the film during the strengthening treatment, and the appearance quality is usually significantly impaired. The inventors examined in detail the correlation between the strengthening conditions and the appearance quality after the strengthening treatment, and found that the Sn-Sb oxide film thickness was 4000 mm or less, and that the glass surface residue during glass strengthening after the film was attached. It has been clarified for the first time that the above problem can be avoided if the stress is 900 kg / cm ² or more and 1300 kg / cm ² or less.

[Function] As described above, by forming the Sn—Sb oxide film having the composition and thickness of the present invention on a sheet glass, it has excellent visible light transmission and near-infrared cut performance, and is formed in the film at the time of strengthening treatment. Thus, a glass free from cracks can be provided.

 Hereinafter, specific examples will be described.

Example 1 A soda lime glass having a size of 150 × 150 mm and a thickness of 4 mm was washed and dried to obtain a substrate. This substrate was fixed by a hanging tool, and kept in an electric furnace set at a predetermined temperature for 5 minutes, then taken out and the following raw material liquid was sprayed on the substrate for about 10 seconds using a commercially available spray gun at an air pressure of 1.5 kg. / cm ² , air volume 5
A sample sprayed at 0 l / min at a spray rate of 120 ml / min was used as a sample. The raw material liquid had the following composition.

It was carried out _{C 4 H 9 SnCl 3 31.8g CH} 3 OH 10.0g H 2 O 10.0g SbCl 3 suitable amount here variously changed by spraying the composition ratio of Sn material and Sb raw material. The film thickness was kept constant at 1800 °. The antimony composition ratio of the obtained film was measured by fluorescent X-ray. Table 1 compares the composition ratio of tin and antimony in the film and the optical characteristics of the obtained film.

Example 2 A Sn—Sb mixed oxide film having a thickness of 4 mm and a size of 300 × 300 mm was applied under the same spraying conditions as in Example 1. Size soda lime glass. Adjust the spray time and adjust the thickness of the obtained film to 15001, 4000Å, 55
00 °. An air-cooling strengthening test was performed using this glass. The higher the furnace temperature, the higher the surface residual stress value,
The degree of reinforcement was found to be strong.

FIG. 1 shows the relationship between the surface residual stress and the appearance characteristics of the reinforced film. When the film thickness is 5500 mm, the residual stress is 900 kg / cm ²
Even if it is suppressed, cracks are formed on the entire surface, and it can be said that it is virtually impossible to strengthen the air cooling. On the other hand, when the film thickness is 4,000 mm or less, if the residual stress is 1300 kg / cm ² or less, no crack occurs and the normal strengthening conditions can be satisfied. In other words, the cracks in the coating appearing during strengthening tend to appear more pronounced as the film thickness increases or as the furnace temperature rises. Turned out not to be.

No change in the optical characteristics before and after the strengthening treatment was observed.

[Effects of the Invention] According to the present invention, as is clear from the examples, it is possible to obtain a glass which is excellent in high visible light transmission and near-infrared ray cut performance and does not generate cracks in the film during the strengthening treatment.

[Brief description of the drawings]

FIG. 1 illustrates the relationship between surface residual stress and appearance characteristics of a reinforced film.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-124426 (JP, A) JP-A-1-192735 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C03C 17/00-17/44 C03B 27/04

Claims (1)

(57) [Claims] 1. A heat ray shielding glass in which a film mainly composed of a mixture of Sn and Sb oxides is formed on a glass substrate, wherein the content of Sb in the mixture film (% by weight in terms of Sb ₂ O ₃ ).
Is 2 to 20%, and the thickness of the mixture coating film is 4000 mm or less, and the glass film coated with the mixture coating is strengthened through a tempering treatment after coating, and the surface residual stress of the glass at that time is 900 kg /
cm ² or more 1300 kg / cm ² have the following values, the visible light transmittance of 40% or more, solar transmittance of 70% or less, the mixture coating film was found to 500 ° C. or more hot glass, Sn
A near-infrared cut-off glass, which is obtained by a thermal decomposition oxidation reaction of a Sb compound and a Sb compound.