JP3144951B2 - Method of manufacturing heat reflection window - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a heat reflecting window used in a microwave oven or an oven.

[0002]

2. Description of the Related Art Generally, a microwave oven and an electronic oven include:
In order to improve the thermal efficiency during the heating and cooking, a heat ray reflective material film is formed on the surface of the front glass window.

As such heat ray reflecting materials, tin oxide / antimony oxide (ATO), indium oxide / tin oxide (ITO), and the like are known. When these metal oxides are formed on a glass substrate, a film is formed. And a transparent heat ray reflective film.

[0004] As a method of forming these heat ray reflection films,
The following methods are known. (1) Vacuum evaporation method (2) Sputtering method (3) CVD method (4) Coating method

[0005]

However, the above (1),
The methods (2) and (3) have complicated and expensive devices and have problems in cost and mass productivity. The method (4) is based on the above (1)
Although there is a possibility of solving the problems of the methods (2) and (3), it has been difficult to form a film that can withstand practical use.

For example, when an organic solution of an inorganic compound such as indium nitrate, indium chloride, stannic chloride or the like is used, the formed film becomes cloudy, or the obtained film lacks mechanical strength and is easily used. Has disadvantages such as scratching. In addition, in the method using an organic acid having a strong ionic bond such as indium octylate, since the organic acid indium is easily hydrolyzed and relatively easily chemically changed, gelling of a coating solution occurs. There is. further,
A method using an organic complex of indium or tin has also been proposed, but in this method, during thermal decomposition of a coating film after being applied to a substrate, evaporation of a tin compound or the like hinders uniformity of the film. However, there is a disadvantage that a low-resistance homogeneous film cannot be obtained.

The electrical resistance of the film and the heat ray reflection characteristic have an inversely proportional relationship as shown in FIG. For this reason, the above-mentioned conventional oxide film has low heat ray reflection characteristics, and is insufficient in function as a heat ray reflection film for a microwave oven or an electronic oven.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a heat-reflection window for a microwave oven or an oven having low resistance, high visible light transmittance, and high heat-ray reflection characteristics. .

[0009]

In order to achieve the above object, the present invention provides a method for heating an organic solution comprising an inorganic indium compound, an organic tin compound, and an organic compound capable of coordinating with both indium and tin. Treating the organic solution
Intermediate complex of indium and tin by partial hydrolysis
Manufacture of a heat reflection window for forming a compound and forming a visible light transmitting film on one or both surfaces of a glass substrate by thermal decomposition of a composition obtained by mixing a polyhydric alcohol with the organic solution.
Method .

[0010]

According to the present invention, an organic solution comprising an inorganic indium compound, an organic tin compound, and an organic compound capable of coordinating with both indium and tin is subjected to heat treatment.
The inorganic indium compound in which one part of the organic compound is coordinated reacts with the water of crystallization contained in the organic tin compound and the inorganic indium compound, and the organic tin compound is partially hydrolyzed to form an intermediate composite compound of indium and tin. This suppresses the nonuniformity of the film due to the evaporation of tin, which is a conventional problem, and gives the obtained film high heat ray reflection characteristics, low resistivity, and high visible light transmittance. The addition of polyhydric alcohols also provides a thickening effect of the solution and the stability of a film obtained by applying and drying the composition on a substrate.

[0011]

Embodiments of the present invention will be described below in detail.
The composition for forming a transparent conductive film in this example is synthesized as follows. First, an inorganic indium compound is mixed with an organic compound capable of coordinating with both indium and tin. Here, the inorganic indium compound may be any compound having an organic compound capable of coordinating with indium or tin and having a ligand that can be substituted. For example, indium nitrate and indium chloride are mentioned, and those having crystallization water are preferable. In addition, an organic compound capable of coordinating with both indium and tin coordinates one part with indium and tin to help form an intermediate compound between them.
It is necessary to have solubility in organic solvents,
Examples include β-diketones, α- or β-ketone acids, esters of the ketone acids, and α- or β-amino alcohols.

Next, an organic solvent and an organic tin compound are added to the solution, and the organic solution is heated. here,
The organotin compound may be any compound that is relatively stable in air, but is easily hydrolyzed by heat treatment. For example, tin carboxylate and tin dicarboxylate are mentioned, and the carbon number is small, tin formate, tin acetate,
Tin oxalate is preferred. The organic solvent may be any solvent that dissolves the organic compound and the inorganic compound used in this embodiment. For example, toluene, aromatic hydrocarbons such as xylene, ethanol, alcohols such as isopropanol, ethyl acetate, acetates such as butyl acetate, acetone, ketones such as diethyl ketone, methoxyethanol, ethers such as ethoxyethanol, Tetrahydrofuran and the like. Further, the temperature of the heat treatment is preferably at or near the reflux temperature of an organic solution comprising an inorganic indium compound, an organic tin compound, and an organic compound capable of coordinating with the compound.

Then, the organic solution after the heat treatment is cooled to around room temperature, a polyhydric alcohol is added, and the mixed organic solution is made a thermally decomposable composition. Here, the polyhydric alcohol gives the effect of thickening the organic solution and the stability of the coating obtained by applying and drying the thermally decomposable composition on the glass substrate. Alcohols may be mentioned, but ethylene glycol and glycerin, which have a small number of carbon atoms and are less likely to remain carbon during thermal decomposition, are preferred.

The heat-decomposable composition thus obtained is applied to a glass substrate, dried, and fired to form a heat ray reflective film. Here, the application of the thermally decomposable composition includes a screen printing method, a roll coating method, a dip coating method,
Although a spin coating method or the like can be used, a dip coating method or a spin coating method is preferable. The firing temperature is not less than the temperature at which the thermally decomposable composition decomposes and not more than the deformation temperature of the glass substrate.
C is preferred.

Hereinafter, the present invention will be described with reference to more detailed examples, but the present invention is not limited to these examples. (Example 1) In an Erlenmeyer flask, 45 g of indium nitrate In (NO ₃ ) ₃ .3H ₂ O was weighed, 50 g of acetylacetone was added, and mixed and dissolved at room temperature. In the solution, 0 [Sn / In + Sn) × 100 and Owt%] ％
8.1 g [Sn / (In + S) n) × 100 30 wt
%] Of stannous oxalate (SnC ₂ O ₄ ) and acetone were added and refluxed. The solution after the reflux was cooled to around room temperature, 5 g of glycerin was added, and the mixture was stirred and mixed to synthesize a thermally decomposable composition. The thermally decomposable composition contains SiO 2
_{The two-} coated glass substrate was dip-coated at a pulling rate of 60 cm / min. The substrate was left at room temperature for 5 minutes, dried at 100 ° C. for 5 minutes, and baked at 500 ° C. for 1 hour. The thickness of the obtained film was 0.10 μm.
Example 2 Indium chloride InCl ₃ .3H ₂ O was used as an inorganic indium compound, and as an organic tin compound,
Using stannous oxalate, [Sn / (In + Sn) × 1
00] to 10 wt%. Others are the same as Example 1. (Example 3) Stannous acetate was used as an organotin compound, and [Sn / (In + Sn) x 100] was adjusted to 10 wt%. Others are the same as Example 1. (Example 4) Using the same thermally decomposable composition as in Example 1, dip pyrolysis to a glass substrate was repeated three times. Others
Same as Example 1. FIG. 1 shows the infrared reflection characteristics of the obtained reflection window. Comparative Example 1 In an Erlenmeyer flask, 45 g of indium nitrate In (NO ₃ ) ₃ .3H ₂ O and 5.4 g [Sn / (In
+ Sn) × 100 wt%] Stannic chloride SnC
added l ₄ · 5H ₂ O and acetone, stirred and mixed to synthesize a thermally decomposable composition. The thermally decomposable composition contains Si
The O ₂ -coated glass substrate was dip-coated at a pulling rate of 60 cm / min. The substrate was left at room temperature for 5 minutes, dried at 100 ° C. for 5 minutes, and baked at 500 ° C. for 1 hour.

Table 1 shows the results of Examples 1 to 4 and Comparative Example 1.

[0017]

[Table 1]

In this embodiment, an example is described in which the heat ray reflective film is formed by dip pyrolysis on both surfaces of the glass substrate. However, the heat ray reflective film may be formed on only one surface by forming a resist on one surface. It is possible.

Further, a pair of electrodes is formed on the formed heat ray reflection film, and an AC or DC electric field is applied to the pair of electrodes to cause this portion to function as a planar heating element, and to scatter and adhere to the portion. Surface cleaning becomes possible.

[0020]

As is clear from the description of the above embodiment,
ADVANTAGE OF THE INVENTION According to this invention, the transparent conductive film excellent in the heat ray reflection characteristic and the transmittance | permeability in a visible region can be obtained easily and cheaply, and what is suitable as a window for heat rays reflection of a microwave oven or an electric oven can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing infrared reflection characteristics of a heat ray reflection window of the present invention.

FIG. 2 is a diagram showing a correlation between electric resistance of a film and heat ray reflection characteristics.

────────────────────────────────────────────────── (5) References JP-A-5-32917 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03C 15/00-23/00

Claims (6)

(57) [Claims] 1. An organic solution comprising an inorganic indium compound and an organic tin compound, and an organic compound capable of coordinating with both indium and tin, is subjected to a heat treatment to partially remove the organic solution.
Intermediate complexation of indium and tin by partial hydrolysis
A method for manufacturing a heat ray reflective window, wherein a visible light transmitting film is formed on one or both surfaces of a glass substrate by thermal decomposition of a composition obtained by forming a compound and mixing the polyhydric alcohol with the organic solution. 2. The compounding ratio of an organotin compound to an inorganic indium compound (Sn / (In + Sn) × 100) is 5
The method for producing a heat ray reflective window according to claim 1, wherein the content is in the range of 20 wt% to 20 wt%. 3. The method according to claim 1, wherein the inorganic indium compound is indium nitrate or indium chloride. 4. The method according to claim 1, wherein the organotin compound is a carboxylate or a dicarboxylate. 5. The coordinable organic compound is selected from the group consisting of β-diketones, α- or β-ketone acids, esters of the ketone acids, and α- or β-amino alcohols. The method for manufacturing a heat ray reflection window according to claim 1, wherein: 6. The method according to claim 1, wherein the composition is applied to a glass substrate, dried, and then fired.