JPH0570178A - Heat ray-reflecting film and its production - Google Patents

Abstract

PURPOSE:To improve electric wave penetration performance by including ultrafine particles of an electrically conductive oxide and one or more metallic oxides selected from silicon oxide, titanium oxide and zirconium oxide and providing a prescribed surface resistivity. CONSTITUTION:(A) An ultrafine particle dispersion is obtained by dispersing an antimony-containing tin oxide, etc., having <=100nm average particle diameter in a dispersion such as an alcohol. (B) A coating solution is then obtained by including one or more of compounds expressed by the formulas Si(OR)nRn, Ti(OR)mLn and Zr(OR)mLn [(m+n) is 4; m is 1-4; n is 0-3; R is 1-4C alkyl; L is chelate coordination group such as acetylaceton or beta-diketone] or their polymers, etc. The components (A) and (B) are then applied to a substrate glass such as normal glass by a spraying method, etc., and subsequently heated to produce a glass article with a heat ray-reflecting film, having 10kOMEGA/square surface resistivity and applied thereto is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat ray reflective film having a radio wave transmitting property, which can be used for glass for automobiles, glass for building materials and the like.

[0002]

2. Description of the Related Art Conventionally, a heat ray reflective film has been obtained by coating a relatively highly conductive substance such as titanium nitride, silver or aluminum by a dry method such as vapor deposition or sputtering. However, the heat ray reflective film coated by these methods has high electric conductivity on the surface and has a high electromagnetic wave shielding property due to its property, and it cannot be used for indoor antennas, glass print antennas, and mobile phones because radio waves cannot be transmitted. There was a flaw.

Further, when titanium nitride, silver, or the like is coated, the reflectance in the visible light region is increased and the visible light transmittance is lowered, and there is a problem that it cannot be used as it is for glass for automobiles. In practice, an antireflection film was applied and used.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a heat ray reflective film having radio wave transmission performance, and a manufacturing method thereof. ..

[0005]

Means for Solving the Problems That is, the present invention is based on heat ray reflection containing ultrafine particles of a conductive oxide and at least one metal oxide selected from silicon oxide, titanium oxide and zirconium oxide as main components. Membrane with surface resistance of 10KΩ
/ □ or more, the heat ray reflective film, and
A heat ray reflective film is produced by applying a coating liquid containing, as a main component, ultrafine particles of a conductive oxide and at least one selected from a silicon compound, a titanium compound and a zirconium compound, and heating the coating liquid. The present invention provides a method for producing a heat ray reflective film.

In the present invention, in order to prevent the heat ray reflecting film from blocking the radio waves entering the room or the radio waves transmitted from the communication equipment in the room, the heat ray reflecting film is 10 KΩ / □.
It is necessary to have a surface resistance value of not less than 100 KΩ / □, preferably not less than 1 MΩ / □. The required lower limit of the surface resistance value of the heat ray reflective film is slightly different depending on the purpose of the transmitted and received radio waves such as FM, AM, TV, telephone, etc., but if it is 1 MΩ / □ or more, it is sufficient for any of these purposes it can.

The heat ray-reflecting film of the present invention contains conductive oxide ultrafine particles in the coating film in order to eliminate the electromagnetic wave shielding property of the conventional heat ray reflecting film of the Drude Mirror type in which the heat ray reflecting performance is expressed by the conductive thin film. It is characterized in that the contact between the conductive particles is restricted by dispersing the particles in the above, and thereby the surface resistance is increased.

As the ultrafine particles of the conductive oxide in the present invention, antimony-containing tin oxide (ATO), tin-containing indium oxide (ITO) and the like can be used, but it is considered from the viewpoint of economical efficiency, chemical durability and reproducibility. Thus, tin oxide containing antimony can be used relatively favorably.

The dispersion medium and dispersion method of the ultrafine particles of the conductive oxide are not particularly limited, and various kinds can be used. For example, adding conductive oxide ultrafine particles to an organic solvent such as water or alcohol and adding acid or alkali to adjust pH
After being adjusted, it can be obtained by dispersing with a commercially available pulverizer such as a colloid mill, a ball mill, a sand mill, a homomixer, or an ultrasonic disperser.

The average particle diameter of the conductive oxide ultrafine particles in the dispersion is preferably 100 nm or less. It is preferably 50 nm or less, particularly preferably 20 nm or less. If particles having a particle size of 100 nm or more are used, the transparency of the coating may be impaired and the strength of the coating may be adversely affected.

The dispersion may be diluted with alcohol, water or the like. A solution containing a silicon compound, a titanium compound and a zirconium compound as a binder component is added to the dispersion liquid of the conductive oxide ultrafine particles to prepare a coating liquid.

Specifically, Si (OR) _m R _n , Ti
(OR) _m L _n , Zr (OR) _m L _n (where m + n
= 4, m = 1 to 4, n = 0 to 3, R = C _{1 to} C ₄ alkyl group, L = acetylacetone group, chelate coordination group such as β-diketone group, and acylate coordination such as stearic acid group. At least one kind of coordination group selected from the group), or at least one kind of these polymers, or a solution containing a partial hydrolyzate thereof is added to the conductive oxide ultrafine particle dispersion. These metal organic compounds may be used alone, or may be a mixture thereof.

These metal-organic compounds not only act as a binder, but also bond with the hydroxyl groups on the surface of the oxide particles in the coating liquid to cover the oxide particles, so that the oxide particles are dispersed in the liquid. It also increases the resistance and effectively works to increase the resistance when it becomes a film.

When antimony-containing tin oxide is used as the ultrafine particles of a conductive oxide, it is preferable to impart a surface resistance of 10 KΩ / □ or more to give radio wave transmission performance and to form a film having heat ray reflection performance. The film composition ratio is ATO: MO ₂ = 50: 5 in terms of oxide (% by weight).
0 to 96: 4, particularly preferable composition ratio is ATO:
MO ₂ = 50: 50 to 90:10 (MO ₂ is SiO ₂ ,
The total of TiO ₂ and ZrO ₂ is shown. ). If the conductive particles are less than this composition ratio, the effective heat ray reflection performance cannot be provided, and if it is more than 96: 4, the film strength is lowered, which is not preferable. MO ₂ is 1 in terms of film strength
It is particularly preferably 0% by weight or more.

The film composition ratio when tin-containing indium oxide is used as the ultrafine particles of the conductive oxide is also the same. When both antimony-containing tin oxide is used, the total of both is the same as the above-mentioned film composition ratio. Can be said. Also,
The coating liquid for forming the radio wave transmission heat ray reflective film preferably has a total solid content of 1 to 30% by weight based on the solvent.

As the base glass in the present invention, it is possible to use a normal plate glass made of soda lime silicate glass, a float plate glass or the like which is usually used as a glass for automobiles and buildings, and a heat ray is added to have a further heat ray shielding performance. Absorption glass can also be used.

In the present invention, a coating liquid containing a metal organic compound as a binder component is applied to a dispersion liquid of the above-mentioned ultrafine particles of a conductive oxide, and the coating liquid is heated to heat ray reflection having radio wave transmission performance. Form a film.

The method of coating the substrate is not particularly limited, and a spray method, a dip method, a roll coating method, a meniscus coating method, a spin coating method, a screen printing method, a flexographic printing method and the like can be used.

The thickness of the heat ray reflective film is from 500Å to 1
μm is preferable, and if it is less than this range, the heat ray reflection performance is inferior, and if it is more than 100 μm, the visible light transmittance of the coating decreases and the transparency is impaired, which is not preferable.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
In the following examples and comparative examples, the evaluation methods of the obtained films are as follows.

1) Surface resistance value The surface resistance value of the film surface was measured with a Hiresta resistance measuring instrument (manufactured by Mitsubishi Yuka). 2) calculate the heat ray reflection performance spectrophotometer (manufactured by Hitachi) by 340 ～1800Nm transmittance, reflectance was measured, solar transmittance according to JIS-R3106 (T _E), the solar reflectance of the (R _E).

3) Visible light transmittance, visible light reflectance The transmittance and reflectance of 380 to 780 nm were measured with a spectrophotometer (manufactured by Hitachi Ltd.), and the visible light transmittance (T _V ) was measured according to JIS-R3106. Calculate the visible light reflectance (R _V ).

[Example 1] Tin oxide ultrafine particles (average particle size 10 nm) containing 9 mol% of Sb were dispersed by a sand mill to obtain an aqueous sol having a solid content of 20% by weight. (Liquid A)

Ethyl silicate polymer (Tama Chemical Industry Co., Ltd.)
Manufactured by the trade name Silicate 40), 10 parts by weight of ethanol and an aqueous solution of hydrochloric acid (9 parts by weight) were added to obtain a solid content of SiO
_It was prepared so as to be 5% by weight in terms of ₂ . (Solution B) 3 parts by weight of a 1: 1 mixture of solution B and water (weight ratio) was added to 1 part by weight of solution A to prepare a coating solution.

This coating solution was applied to a float glass plate having a thickness of 2 mm by using a spin coater at 500 rpm, 3
After applying it for 0 seconds, dry it for 10 minutes in a dryer at 180 ° C, and
A coat film was obtained by baking for 30 minutes in an electric furnace at 00 ° C.
The characteristics of this coat film are shown in Table 1.

Example 2 Zirconium acetylacetone butoxide (Zr (C ₅ H ₇ O ₂ ) ₂ (OC ₄ H ₉ ) ₂
Hydrochloric acid aqueous solution to Zr of 16m against Zr
The ol ratio was added to obtain a 10 wt% solution in terms of ZrO ₂ . (C liquid)

The solution A shown in Example 1 was diluted with ethanol to 1 part.
Solution C was diluted to 0% by weight and added so that the weight ratio of ATO: ZrO ₂ was 20: 1 to obtain a coating solution. This coating solution was applied to a float glass plate having a thickness of 2 mm using a spin coater at 750 rpm for 5 seconds, dried in a dryer at 180 ° C. for 10 minutes, and baked in an electric furnace at 600 ° C. for 5 minutes to obtain a coating film. It was The characteristics of this coat film are shown in Table 1.

[Example 3] ATO: ZrO ₂ : SiO ₂ = 10: 1: 1 was added to the coating liquid shown in Example 2.
The solution B shown in Example 1 was added to give a (weight ratio) to obtain a coating solution. This coating solution was applied to a float glass plate with a thickness of 2 mm using a spin coater.
After coating at 50 rpm for 5 seconds, use a dryer at 180 ° C for 10
It was dried for a minute and baked in an electric furnace at 600 ° C. for 5 minutes to obtain a coat film. The characteristics of this coat film are shown in Table 1.

Example 4 Titanium acetylacetone isopropoxide (Ti (C ₅ H ₇ O ₂ ) ₂ (OC ₃ H
₇ ) ₂ ethanol solution of H ₂ O to Ti 8mo
l ratio was in HCl (36.5%) was added to TiO ₂ 20 wt% and a solution of 10 wt% in terms of TiO _2.
(D liquid)

The liquid A shown in Example 1 was diluted with ethanol to a solid content of 10% by weight, and the liquid D was mixed with ATO: Ti.
O ₂ was added at a weight ratio of 10: 3 to obtain a coating liquid. This coating solution was applied to a float glass plate having a thickness of 2 mm using a spin coater at 750 rpm,
After coating for 5 seconds, dry in a dryer at 180 ° C for 10 minutes, and
A coat film was obtained by baking in an electric furnace at 00 ° C for 5 minutes. The characteristics of this coat film are shown in Table 1.

[Example 5] ATO: TiO ₂ : SiO ₂ = 10: 3: 2 was added to the coating liquid shown in Example 4.
The solution B shown in Example 1 was added to give a (weight ratio) to obtain a coating solution. This coating solution was applied to a float glass plate with a thickness of 2 mm using a spin coater.
After coating at 50 rpm for 5 seconds, use a dryer at 180 ° C for 10
The coating film was dried by minute drying and baked in an electric furnace at 600 ° C. for 5 minutes. The characteristics of this coat film are shown in Table 1.

Example 6 Ultrafine indium oxide particles (average particle size 20 nm) containing 5 mol% of Sn were dispersed by a sand mill to obtain an aqueous sol having a solid content of 8% by weight. (E
Liquid) Ethyl silicate polymer (Tama Chemical Industry Co., Ltd., trade name silicate 40) 10 parts by weight of ethanol, nitric acid aqueous solution (9
(Parts by weight) was added to prepare a solid content of 3% by weight in terms of SiO ₂ . (F liquid)

A coating solution was prepared by adding 7 parts by weight of solution F to 5 parts by weight of solution E. This coating liquid is 2mm thick
750r using a spin coater on the float glass plate
The coating film was obtained by applying the coating film at pm for 5 seconds and then drying in a dryer at 180 ° C. for 10 minutes and baking in an electric furnace at 600 ° C. for 5 minutes. The characteristics of this coat film are shown in Table 1.

[Comparative Example 1] Indium octylate and tin octylate were dissolved in a xylene solvent so that Sn / In was 5% by mol ratio (solid content 5% by weight) to obtain a coating liquid. This coating liquid is 2mm thick
750r using a spin coater on the float glass plate
The coating film was obtained by applying the coating solution at pm for 5 seconds and then drying in a dryer at 180 ° C. for 10 minutes and baking in an electric furnace at 500 ° C. for 30 minutes. The characteristics of this coat film are shown in Table 1.

[0035]

[Table 1]

As is clear from the above test results, the heat ray reflective film according to the present invention can reflect heat rays without lowering the surface resistance value. Further, since the visible light reflectance is low, it can be used as a heat ray reflective film for automobile glass without overcoating with an antireflection film.
Of course, an antireflection film may be formed.

[0037]

As described above, according to the present invention, a heat ray reflective film having a high surface resistance can be formed, so that radio wave transmission performance can be provided. Therefore, when the radio wave receiver and / or the radio wave transmitter (antenna, etc.) is placed indoors, the radio wave receiver does not attenuate the electric wave to be received or the electric wave that has been emitted, and the glass with the print antenna is Even when the heat ray reflective film is formed so as to cover the printed antenna, it is possible to prevent the radio wave from being attenuated by the heat ray reflective film to reduce the gain of the antenna. In this way, the flow of heat rays into the room can be reduced without hindering the use of the communication device indoors.

Claims (5)

[Claims] 1. Ultrafine particles of a conductive oxide and at least one selected from silicon oxide, titanium oxide and zirconium oxide.
A heat ray reflective film comprising a kind of metal oxide (hereinafter referred to as MO ₂ ) as a main component, and having a surface resistance of 10 KΩ / □ or more. 2. A conductive oxide ultrafine particle having a particle size of 100 nm.
At least one of antimony-containing tin oxide and tin-containing indium oxide having the following average particle size (hereinafter, T
_2. The heat ray-reflecting film according to claim 1, wherein the heat ray-reflecting film contains ultrafine particles (referred to as “O”), and TO is contained in a total amount of 50% by weight or more and MO ₂ in a total amount of 4% by weight or more in terms of oxide. 3. A heat ray reflective film is produced by applying a coating liquid containing ultrafine particles of a conductive oxide and at least one selected from a silicon compound, a titanium compound and a zirconium compound as main components, and then heating. A method of manufacturing a heat ray reflective film, comprising: 4. The coating liquid is Si (OR) _m R _n ,
Ti (OR) _m L _n , Zr (OR) _m L _n (where m
+ N = 4, m = 1 to 4, n = 0 to 3, R = C _{1 to} C ₄ alkyl group, L = acetylacetone group, chelate coordination group such as β-diketone group, and acylate coordination such as stearic acid group. At least one kind of coordination group selected from the group), or at least one kind of these polymers, or a partial hydrolyzate thereof.
A method for producing the heat ray reflective film as described. 5. A glass article having a surface coated with the heat ray reflective film according to claim 1 or 2.