JPWO2006112371A1 - Insulating window plate - Google Patents

Abstract

Provided is a heat-insulating window plate that is excellent in visible light transmission and radio wave transmission, has low infrared transmission, and can be applied to parts that require mechanical durability such as automotive window glass. The transparent conductive oxide fine particles having an average primary particle diameter of 100 nm or less are in a matrix mainly composed of silicon oxide in a mass ratio of [transparent conductive oxide fine particles] / [silicon oxide] = 10/20 to 10 / 0.5. The first layer having a layer thickness of 300 to 400 nm and the second layer containing silicon oxide are dispersed on the surface of the transparent plate-like body on the surface of the transparent plate-like body / first layer / second layer. The layers are provided in the order of layers, and the layer thickness ratio of the second layer / first layer is 0.1 to 0.5.

Description

  The present invention relates to a heat insulating window plate, and more particularly to a heat insulating window plate excellent in radio wave transmission, wear resistance, and transparency.

  In recent years, for the purpose of insulating windows for the purpose of reducing temperature rise and cooling load in cars and buildings by shielding infrared rays flowing into cars and buildings through transparent window plates such as glass for vehicles and glass for buildings. A plate-like body is employed (for example, Patent Document 1). In addition, vehicle glass and architectural glass are often required to have high visible light transmittance in order to ensure safety and visibility.

  Many methods have been proposed so far to add infrared shielding performance to a glass plate to enhance heat ray shielding. For example, there is an attempt to add infrared shielding performance to the glass plate itself by adding infrared absorbing ions to the glass, or an attempt to add infrared shielding performance by forming a conductive film on the glass substrate surface. It has been proposed and used in practice.

  However, it is difficult to increase the infrared absorptivity while keeping the visible light transmittance high with the glass plate in which the infrared absorptive ions are added to the glass, and in particular, the medium wavelength infrared light having a wavelength of 1.5 μm to 2.7 μm. It was difficult to improve the shielding property. In addition, in the method of forming a conductive film on the surface of a glass plate, radio waves cannot pass through the glass because of the conductive film, and radio wave permeability of the opening is required with the recent spread of mobile communication. Inconvenience may have arisen from this. As described above, it has been extremely difficult to produce a window plate having transparency, infrared shielding properties, and radio wave transmission properties.

  In order to solve the above problems, a coating in which fine particles of indium oxide (ITO) doped with tin oxide, which exhibits high infrared shielding properties, are dispersed in a binder is applied on a transparent plate-like body to provide heat insulation properties. A method for obtaining a window plate has been proposed (Patent Documents 2 and 3). With this method, it is possible to impart infrared shielding properties while maintaining a relatively high visible light transmittance, and it is also possible to impart radio wave transparency because the conductivity as a film is suppressed by the presence of a binder. Become.

  In the above method, the binder that is usually used is an organic binder or an inorganic binder. However, the organic binder has poor mechanical durability of the coating film, and is required to have mechanical durability such as an automotive door glass plate. There was a problem that it was not possible to use it on the site. On the other hand, materials such as the sol-gel method are often used as inorganic binders, but in order to produce coatings that are still durable enough to be used in areas where mechanical durability is required. However, it was necessary to perform heat treatment at a relatively high temperature, for example, 400 ° C. or higher, preferably 500 ° C. or higher.

  However, the ITO conductor is an oxygen-deficient semiconductor, and when it is placed at a temperature of 300 ° C. or higher in the presence of oxygen, free electrons are lost due to oxidation, and the infrared shielding property is lost. For this reason, in order to produce a coating film that maintains infrared shielding properties and is excellent in mechanical durability, it is necessary to perform heat treatment in a non-oxidizing atmosphere that is overwhelmingly disadvantageous in terms of cost. However, it is easy and inexpensive to produce a highly durable heat insulating window plate in heat treatment in the atmosphere, and is also applicable to parts that require high mechanical durability such as automotive window glass plates. A heat insulating window plate having an infrared shielding layer that can be produced has not been obtained so far.

  In recent years, Patent Document 4 proposes a glass plate with a heat ray shielding film having excellent wear resistance and transparency. This glass plate with a heat ray shielding film prevents the oxidation of the heat ray shielding film by covering the heat ray shielding film with a silicon oxide protective film containing an alkali metal, and is characterized by both excellent heat ray shielding properties and wear resistance. is there. However, since the protective film containing an alkali metal has relatively low chemical resistance, there is a possibility that it cannot be applied to a part exposed to a severe external environment for a long period of time, such as an automobile door glass plate or a window glass plate. Recently, there has been a demand for the development of a heat-insulating window plate having both high infrared shielding properties and radio wave transmission properties, and excellent mechanical and chemical durability.

JP-A-10-279329 (Claims) JP-A-7-70482 (Claims) JP-A-8-41441 (Claims) JP 2004-338985 A (Claims, Examples)

  INDUSTRIAL APPLICABILITY The present invention is a heat insulating window plate that has high visible light transmittance, low infrared transmittance, excellent radio wave transmittance, and can be applied to parts that require mechanical durability such as automotive window glass. The object is to provide a body.

  The present invention provides a transparent plate-like body and an infrared shielding layer comprising the following first layer and the following second layer provided on the surface of the plate-like body (however, the first layer is present on the plate-like body side). The transparent conductive oxide fine particles having an average primary particle diameter of 100 nm or less in a matrix mainly composed of silicon oxide in a mass ratio of [transparent conductive oxide fine particles] / [silicon oxide] = 10/20 to 10 / 0.5 in a dispersed manner and having a layer thickness of 300 to 400 nm, the second layer is a layer containing silicon oxide, and the second layer / second layer A layer thickness ratio of one layer is 0.1 to 0.5.

  The heat insulating window plate of the present invention has high visible light transmittance, low infrared transmittance, high radio wave permeability, and high mechanical durability. In particular, since the layer thickness of the first layer is moderate, it is possible to express radio wave transmissivity of mobile phones, optical beacons, etc. while maintaining high infrared shielding properties, especially for automotive window glass applications. Preferably used.

  In addition, since a protective film material having a high function to relieve the film stress generated at the interface between the first layer and the second layer (protective film) at the time of firing is used, even if the protective film is thin, the oxygen barrier property is maintained. Therefore, it is excellent in productivity.

Sectional drawing of the plate-like body for heat insulation windows by one embodiment of this invention. The schematic of the measuring method of the radio wave loss in the Example of the present invention.

Explanation of symbols

10. · Transparent plate 20 ·· First layer (infrared shielding layer made of (ITO + silicon oxide))
30 .. Second layer (protective layer containing silicon oxide)
40 ··· Receiver 50 ··· Sample 60 · · Transmitter 70 · · Network analyzer

The components of the present invention will be described in detail below.
First, the first layer (20 in FIG. 1) will be described.
The transparent conductive oxide fine particles having an average primary particle size of 100 nm or less is a constituent factor for developing infrared shielding properties, and it is important that the average primary particle size is 100 nm or less. If the average primary particle size is larger than this, it is not preferable because it causes clouding (cloudiness, haze) due to scattering when a film is formed on the surface of a transparent plate. The average primary particle diameter is preferably 5 to 50 nm from the viewpoint of maintaining transparency.

  The transparent conductive oxide fine particles that exhibit infrared shielding properties are preferably fine particles composed of one or more selected from the group consisting of indium oxide, tin oxide, and zinc oxide. From the viewpoint of infrared shielding properties, fine particles made of a material in which tin oxide is mixed with indium oxide (hereinafter referred to as ITO) are preferable. When the mixing ratio of tin oxide and indium oxide of ITO is expressed by the number of indium atoms to the number of tin atoms (In / Sn), it is preferable that In / Sn = 2 to 20, and in particular, In / Sn = 3 to 10 preferable.

The matrix mainly composed of silicon oxide is a component that functions as a binder of the transparent conductive oxide fine particles, and has a function of increasing the adhesion to the surface of the transparent plate-like body and the film hardness. By the way, since the transparent conductive oxide fine particles themselves are excellent in conductivity, when the transparent conductive oxide fine particles are in close contact with each other continuously in the coating, the coating itself develops conductivity and adversely affects radio wave transmission. The matrix mainly composed of silicon oxide has the effect of limiting the contact between the transparent conductive oxide fine particles and preventing the coating itself from becoming a conductive film, and is an important constituent factor for developing the radio wave transmission of the coating. is there. Here, the silicon oxide does not need to have a composition of SiO _{2 in} a strict sense, and may be present as an amorphous component including a network structure of Si—O—Si bonds (siloxane bonds). . In addition, the matrix mainly composed of silicon oxide may contain constituent elements other than Si and O, and Ti, N, and a small amount of components up to about 5% by mass ratio, such as C and Sn. , Zr, Al, B, P, Nb, Ta and the like may be included.

  In the first layer, the matrix needs to be present at a mass ratio of [transparent conductive oxide fine particles] / [silicon oxide] = 10/20 to 10 / 0.5. By setting the ratio to 10 / 0.5 or less, it becomes possible to maintain the adhesion and hardness of the coating and to maintain radio wave transmission. On the other hand, the required infrared shielding property can be maintained by setting the ratio to 10/20 or more. Preferably, the ratio is in the range of [transparent conductive oxide fine particles] / [silicon oxide] = 10/10 to 10 / 0.5.

  In the present invention, the first layer has a thickness of 300 to 400 nm. By setting the layer thickness to 300 nm or more, a desired solar transmittance can be obtained, the infrared shielding property can be sufficiently secured, the reflected color is hardly changed by abrasion, and the appearance quality can be prevented from being deteriorated. On the other hand, by setting the layer thickness to 400 nm or less, it is possible to prevent visible light from diffusing and lowering transparency, and to reduce the conductivity of the infrared shielding layer. As a result, high-frequency radio waves required for glass plates for vehicles are required. Can be secured.

  On the other hand, antenna functions may be added to vehicle windows, especially automobile windows. However, if the window radio wave transmission loss is large, radio wave reception performance deteriorates, so the window glass for automobiles has radio wave permeability. It is required to do. The reception sensitivity of the antenna can be adjusted by the antenna pattern shape and the size of the antenna pattern formation area. However, when an antenna pattern is applied to the window glass, the installation area and appearance are limited. Need to be received. In recent years, since signals to be received by automobiles have become higher in frequency, radio waves have directivity. For example, when an antenna pattern is installed on the rear glass and an infrared shielding plate-like body is provided on the sliding window, the sliding window cannot be received unless the radio wave is sufficiently transmitted. Therefore, it is required not to impair the radio wave transmission performance particularly at high frequencies. In order to improve the reception sensitivity of the window glass antenna, it is useful to suppress the transmission loss of the sliding window as much as possible, and the transmission loss can be suppressed by setting the thickness of the first layer to 400 nm or less. . Especially, it is preferable when the layer thickness of the first layer is in the range of 300 to 330 nm because high infrared shielding properties and radio wave transmission properties can be obtained, and particularly preferably in the range of 310 to 320 nm.

Specifically, the radio wave transmission loss of the infrared shielding layer composed of the first layer and the second layer (the radio wave transmission loss T _LW of the heat insulating window plate at a frequency of 1 GHz and the transparent plate at a frequency of 1 GHz It is preferable to suppress the difference (T _LW −T _LG ) from the radio wave transmission loss T _LG to 2 dB or less. More preferably, the transmission loss of the radio wave is 1 dB or less.

  Next, the second layer (30 in FIG. 1) will be described. The second layer is a constituent factor contributing to the improvement of the mechanical durability of the coating, and as an oxygen barrier film for preventing the oxidation of the transparent conductive oxide fine particles when the coating is fired at a high temperature as will be described later. work. The second layer is a layer containing silicon oxide. The second layer is preferably a dense layer made of a uniform oxide having silicon atoms and oxygen atoms as main constituent atoms. The second layer may contain a small amount of nitrogen atoms bonded to Si (for example, about 5% or less by mass ratio). That is, a part of the silicon oxide in the second layer may be silicon oxynitride.

  In the present invention, the layer thickness ratio of the second layer / the layer thickness of the first layer needs to be 0.1 to 0.5. If the layer thickness ratio is less than 0.1, the wear resistance cannot be maintained, and the oxygen barrier property is insufficient. On the other hand, if the layer thickness ratio exceeds 0.5, the film may crack, and the visible light transmittance and transparency may be reduced. Especially, when layer thickness ratio is made into the range of 0.2-0.5, it is preferable at the point which can express abrasion resistance, infrared rays shielding, radio wave permeability, and transparency with sufficient balance.

  Specifically, the thickness of the second layer is preferably 80 to 140 nm. If the layer thickness is less than 80 nm, the oxygen barrier property is insufficient, and good infrared shielding properties may not be maintained. On the other hand, if it exceeds 140 nm, cracks as described above are likely to occur, and decomposition components generated from the lower layer during firing, such as organic components, are difficult to escape, the coating is colored, visible light transmittance and transparency There is also a possibility that the property may be lowered.

  In the present invention, on the transparent plate-like body, the heat insulating property having the infrared shielding layer (where the first layer exists on the transparent plate-like body side) in which the first layer and the second layer are adjacent in this order. A window plate is provided. In this heat-insulating window plate, in the abrasion resistance test specified in Section 3.7 of JIS-R3212 (1998), the amount of increase in cloudiness due to wear after 1000 rotation tests with a CS-10F abrasion wheel Is preferably 5% or less. As a result, it can be applied to parts that require extremely high mechanical durability, such as automotive door glass plates, and can exhibit both infrared shielding properties and radio wave transmission properties.

  In addition, when used as a window glass plate for automobiles, high visible light transmittance may be required depending on the part. For that purpose, visible light transmission as an infrared shielding layer (not including a glass substrate) is required. The rate is preferably 90% or more, more preferably 95% or more, and particularly preferably 98% or more. The visible light transmittance here refers to the visible light transmittance of a single coating film calculated from a calculation formula defined in JIS-R3212. By forming the infrared ray shielding layer having a visible light transmittance of 90% or more on the surface of the glass substrate, it is possible to prevent the visible light transmittance from being significantly lowered. That is, 90% or more of the visible light transmittance of the glass substrate can be maintained.

  Moreover, the transparent plate-shaped body (10 in FIG. 1) used for this invention is not specifically limited, The glass plate which consists of an inorganic type glass material and the glass plate which consists of organic type glass materials can be illustrated. It is preferable to use a glass plate made of an inorganic glass material for automobile windows, particularly for windshields and sliding windows. Examples of the inorganic glass material include glass materials such as ordinary soda lime glass, borosilicate glass, alkali-free glass, and quartz glass.

  As the inorganic glass plate, glass that absorbs ultraviolet rays or infrared rays can also be used. Specifically, the visible light transmittance defined by JIS-R3212 (1998) is preferably 70% or more, particularly preferably 72% or more, and the transmittance of light having a wavelength of 1 μm is preferably 30% or less, particularly The effect is particularly high when a glass plate having a transmittance of 25% or less and a light transmittance of 2 μm is preferably 40 to 70%, particularly preferably 45 to 65%. In the infrared shielding layer of the present invention, the shielding property in the near-infrared region near 1 μm is not so high, and a glass plate having a high shielding property for light having a wavelength in the vicinity of 1 μm is used as a transparent plate-like body. An excellent infrared shielding property can be provided over the outer region.

The heat insulating window plate of the present invention is preferably produced as follows.
(1) On the surface of the transparent plate-like body, a dispersion for forming a lower layer containing transparent conductive oxide fine particles having an average primary particle diameter of 100 nm or less is applied, dried, and then the transparent conductive oxide fine particles Is formed (hereinafter also referred to as the lower layer).
(2) An upper layer forming composition containing a silicon compound that can form a silicon oxide gel (hereinafter also referred to as a silicon compound) is applied on the lower layer, and a layer containing a silicon compound and / or a gelled product thereof ( Hereinafter, it is also referred to as an upper layer).
(3) The transparent plate-like body on which the two layers are formed is fired at a temperature at which the temperature of the transparent plate-like body is 400 to 750 ° C. in an atmosphere containing oxygen.

  The state of aggregation of the transparent conductive oxide fine particles in the first layer after firing reflects the state of aggregation in the composition for forming the lower layer. Therefore, in order to maintain the transparency and radio wave transparency of the coating, The conductive oxide fine particles are preferably highly dispersed in the lower layer forming composition. As the dispersion state, the number average aggregate particle diameter is preferably 500 nm or less, more preferably 200 nm or less, and further preferably 100 nm or less. As the dispersion medium, various solvents such as polar solvents such as water and alcohol, and nonpolar solvents such as toluene and xylene can be appropriately used. As a method for dispersing, a known method can be used, and a media mill such as ultrasonic irradiation, a homogenizer, a ball mill, a bead mill, a sand mill, and a paint shaker, or a high-pressure impact mill such as a jet mill or a nanomizer can be used.

When the step (2) is employed, a porous layer is formed as a lower layer, and a silicon compound contained in an upper layer forming composition described later is infiltrated into the voids of the lower layer when the upper layer is formed. A layer in which the compound or gelated product thereof is filled in the voids can be formed.
When the lower layer is a porous layer, a silicon compound contained in the composition for forming an upper layer described later penetrates into the voids in the lower layer at the time of application and reaches the surface of the transparent plate-like body. Therefore, it is not essential to add a silicon compound to the dispersion for forming the lower layer, but it may be added.

  The silicon compound refers to a component that can be converted into a silicon oxide matrix having a siloxane bond by heating (hereinafter also referred to as a siloxane matrix material). The siloxane matrix material is a compound that can form a rigid and transparent silicon oxide matrix by forming a siloxane bond (Si—O—Si) by heating to form a three-dimensional network. Specific examples include alkoxysilanes used in the sol-gel method, partial hydrolysates of the alkoxysilanes, partial hydrolysis condensates of the alkoxysilanes, water glass, and polysilazane. Among them, polysilazane, tetraalkoxysilane, a partial hydrolyzate of tetraalkoxysilane, or a partial hydrolysis condensate of tetraalkoxysilane is preferable, and polysilazane is particularly preferable.

The _{^{polysilazane, -SiR 1 2 -NR 2 -SiR 1}} 2 - is a general term for ^(R 1, ^{R 2} are each independently hydrogen or a hydrocarbon group), a linear or cyclic compound having a structure represented by, This is a material in which Si—NR ² —Si bonds are decomposed by reaction with moisture to form a Si—O—Si network. Compared with a silicon oxide-based film obtained from tetraalkoxysilane or the like, a silicon oxide-based film obtained from polysilazane has higher mechanical durability and gas barrier properties. Note that silicon oxide obtained from polysilazane may contain a small amount of nitrogen atoms, and it is considered that silicon oxynitride is partially formed. The silicon oxide in the present invention may be silicon oxide containing such a nitrogen atom. The mass ratio (mass ratio [SiO ₂ ] / [TiO ₂ ], etc.) for silicon oxide containing such nitrogen atoms is a numerical value (oxidation) calculated assuming that all of the silicon atoms are silicon atoms of silicon oxide. (Numerical value converted to silicon).

In the present invention, the polysilazane is a perhydropolysilazane in which R ¹ = R ² = H in the above chemical formula, a hydrocarbon group such as R ¹ = methyl group, and a partially organized polysilazane in which R ² = H, or these Mixtures are preferably used. Infrared shielding layers formed using these polysilazanes are highly suitable because of their high oxygen barrier properties. A particularly preferred polysilazane is perhydropolysilazane.
Further, the lower layer forming dispersion may contain other elements or compounds thereof that can be glass forming or modifying components, such as Ti, Sn, Zr, Al, B, P, Nb, and Ta.

  When the silicon compound is added to the dispersion for forming the lower layer, the abundance ratio between the transparent conductive oxide fine particles and the silicon compound is [transparent conductive oxide fine particles] / [silicon oxide] = 1 as a mass ratio in terms of oxide. / 2 or more is preferable, and more preferably 1/1 or more. By setting the ratio to 1/2 or more in terms of mass ratio, sufficient infrared shielding properties can be secured.

  The lower layer-forming dispersion obtained as described above is applied onto the surface of a transparent plate to form a lower layer. The coating method is not particularly limited, and a known method such as a dip coating method, a spin coating method, a spray coating method, a flexographic printing method, a screen printing method, a gravure printing method, a roll coating method, a meniscus coating method, or a die coating method is used. be able to.

Here, when ITO is used as the infrared shielding fine particles, known ITO fine particles can be used. If the siloxane matrix material is used, not only ordinary cubic ITO but also hexagonal ITO, which is generally said to be inferior in terms of infrared shielding properties, can be used. Especially, in this invention, when forming a lower layer, it is preferable to employ | adopt the following process (1 ') instead of said process (1).
(1 ′) On the surface of the transparent plate-like body, the c light source in the xy chromaticity coordinates, the powder color in the 2 ° field of view has an x value of 0.3 or more, a y value of 0.33 or more, and an average primary A lower layer-forming dispersion liquid containing ITO fine particles having a particle diameter of 100 nm or less is applied and dried to form a lower layer having a configuration in which the ITO fine particles are dispersed.

  The ITO fine particles used here preferably have a c light source in the xy chromaticity coordinates and a powder color in a 2 ° field of view having an x value of 0.3 or more and a y value of 0.33 or more. Such ITO fine particles themselves do not have infrared shielding properties, but reduction occurs in the film in a subsequent baking step, and carriers are generated to form a film having infrared shielding properties.

  The above ITO fine particles can be produced simply by firing the precursor powder obtained by the coprecipitation method or the like in the air or in a normal inert gas such as nitrogen. Unlike conventional ITO fine particles with high-performance infrared shielding that do not require firing in a reducing atmosphere such as dangerous hydrogen or in a pressurized inert atmosphere, it is safer and cheaper Can be produced.

  The ITO fine particles preferably have an average primary particle size of 100 nm or less from the viewpoint of transparency. It is particularly preferable to use ITO fine particles having a crystallite diameter calculated from powder X-ray diffraction analysis of 15 to 50 nm. If the crystallite size is smaller than this, high infrared shielding properties cannot be developed even after reduction in the film, and transparency may be lowered with fine particles having a crystallite size larger than this. It is.

  The lower layer formed on the transparent plate-like body as described above is preferably dried at a temperature of 200 ° C. or lower. In this step, the main purpose is to volatilize and remove the solvent component and the like in the film, and it is uneconomical because there is no effect even if the temperature is raised further. The treatment time is preferably about 30 seconds to 2 hours. Moreover, the minimum of practical temperature is about 50 degreeC, More preferably, it is 120 degreeC or more. Although the solvent component may be removed even at less than 50 ° C., it is not practical because it takes time. However, when the lower layer forming dispersion does not contain a silicon compound, the lower limit may be around room temperature. In either case, the semi-curing atmosphere may be air or drying in a non-oxidizing atmosphere, but the effect of drying in a non-oxidizing atmosphere cannot be particularly expected.

  In addition, before and after this drying process, during the drying process, or instead of the drying process, irradiation with ultraviolet rays having a wavelength of 300 nm or less for 1 minute or longer is also preferably performed. This irradiation with ultraviolet rays may be as simple as leaving the coated plate under a lamp containing ultraviolet rays having a short wavelength of 300 nm or less, and a mercury lamp is preferably used as the lamp. In particular, a lamp called a low-pressure mercury lamp that emits a large amount of ultraviolet rays having a wavelength of 300 nm or less is highly effective. Ultraviolet light having a wavelength of 300 nm or less contributes to the decomposition of organic substances in the film, and has a function of easily removing organic components from the film during firing, which will be described later.

  Further, curing by vacuum drying is also preferably performed before and after the drying process, during the drying process, or instead of the drying process. At this time, although depending on the coating method and the type of solvent contained, the degree of vacuum is preferably about 0.01 to 10 kPa, and the treatment time is about several seconds to several minutes.

  An upper layer is preferably formed by applying an upper layer-forming composition containing a silicon compound adjacent to the semi-cured lower layer obtained as described above. The upper layer functions as an oxygen barrier film that prevents oxygen from being supplied to the transparent conductive oxide fine particles in the lower layer during baking, which prevents the transparent conductive oxide fine particles from being oxidized.

  As the silicon compound in the composition for forming the upper layer, perhydropolysilazane in which R in the above general formula is hydrogen is preferably used from the viewpoint of producing a hard film. The second layer formed from this polysilazane has a relatively high oxygen barrier property and is very suitable as the second layer forming material used in this step. It is preferable that a curing catalyst, a solvent, and an activator are added to the upper layer forming composition. When polysilazane is used as the silicon compound in the upper layer forming composition, the amount of polysilazane is the upper layer forming composition. 20% or less is desirable by mass ratio with respect to the whole. Further, the upper layer forming composition may contain a small amount of Ti, other metal sources that do not have film-forming properties, and the like.

  The upper layer-forming composition is applied onto a film-formed, semi-cured lower layer. As described above, when the lower layer is porous, the composition penetrates into the lower layer film and is transparent in the lower layer film. It also acts as a binder between the conductive oxide fine particles and an adhesion improver with the surface of the transparent plate. In particular, when the siloxane matrix material is not included in the dispersion for forming the lower layer or when only a small amount of the siloxane matrix material is included, the penetration of the composition for forming the upper layer becomes significant. For this reason, even when the ratio of the siloxane matrix material in the lower layer forming dispersion is 5% or less in terms of oxide relative to the transparent conductive oxide fine particles, It can be set as the structure which contains 5 to 200% of silicon oxide by mass ratio with respect to transparent conductive oxide microparticles | fine-particles in a 1st layer, and becomes a 1st layer which satisfies the structure of this invention. As a method for forming the upper layer, a known technique can be used as in the method for forming the lower layer.

  After forming a laminated film as described above, it is preferable to form the first layer and the second layer by baking at a temperature of 400 ° C. or more to cure the coating. The firing time is usually about 30 seconds to 2 hours. The firing atmosphere can be carried out in an atmosphere containing oxygen, such as normal air, and is economical. Firing in a non-oxidizing atmosphere is also possible, but it is not preferable because it is very expensive to maintain the atmosphere, particularly when producing a large window glass or the like. In particular, when producing a tempered glass used as a window glass for automobiles, the temperature is raised to a temperature close to 650 to 700 ° C. in the atmosphere, and then subjected to a tempering treatment by air cooling. Since the layer does not show deterioration in infrared shielding properties even after firing for strengthening treatment, it can be fired using the high-temperature heat of this strengthening process, and the infrared shielding layer has high durability. It is possible to efficiently and economically manufacture tempered glass sheets for automobiles and buildings. The heat treatment temperature is preferably a temperature at which the temperature of the transparent plate-like body is 400 to 750 ° C., particularly 500 to 700 ° C.

  Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. In addition, the average particle diameter of the conductive oxide fine particles in the formed infrared shielding layer was estimated by TEM observation, and the obtained glass with an infrared shielding layer was evaluated as follows.

[Evaluation]
(1) Layer thickness: Cross-sectional observation of the film was performed with a scanning electron microscope (manufactured by Hitachi, Ltd .: S-800), and the layer thicknesses of the first layer and the second layer were obtained from the obtained observation images.
(2) Visible light transmittance (Tv): The transmittance of a glass plate with an infrared shielding layer of 380 to 780 nm is measured with a spectrophotometer (manufactured by Hitachi, Ltd .: U-3500), and according to JIS-R3212 (1998). Visible light transmittance was calculated.
(3) The visible light transmittance [%] of the infrared shielding layer alone is compared with the visible light transmittance of the glass substrate alone measured by the method of 2) and the visible light transmittance of the glass plate with the infrared shielding layer. Visible light transmittance of glass plate with infrared shielding layer) / (visible light transmittance of glass substrate alone) × 100%.

(4) Solar transmittance (Te): The transmittance of a glass plate with an infrared shielding layer of 300 to 2100 nm was measured with a spectrophotometer (manufactured by Hitachi, Ltd .: U-3500), and the solar radiation was measured with JIS-R3106 (1998). The transmittance was calculated. In addition, the infrared shielding performance in this invention was expressed by the performance of solar radiation transmittance.
(5) Abrasion resistance: Using a Taber type abrasion resistance tester, a wear test of 1000 rotations was performed with a CS-10F wear wheel by the method described in JIS-R3212 (1998), and the degree of scratches before and after the test was determined. It measured by the haze value (haze value), and evaluated by the increase amount of the haze value.
(6) Chemical resistance: 0.05 mol / liter sulfuric acid solution and 0.1 mol / liter sodium hydroxide solution were dropped on the second layer, left at 25 ° C. for 24 hours, then washed with water before and after the test. Changes in appearance and characteristics were tracked. Those with no change in characteristics and appearance were accepted.

(7) Radio wave loss: As shown in FIG. 2, radio wave transmission loss at a frequency of 1 GHz was measured with a network analyzer (manufactured by Hewlett Packard: 8510B). At this time, the size of the measurement sample was 300 mm × 300 mm, and the receiver and the transmitter were each installed at a distance of 160 mm from the sample.
(8) Transparency: Transparency (haze value) of visible light transmitting through the glass plate with an infrared shielding layer was measured with a haze meter (manufactured by Suga Test Instruments Co., Ltd .: HZ-1).

[Example of preparation of transparent conductive oxide fine particle dispersion]
10 g of ITO fine particles having a powder color (x, y) = (0.353, 0.374) on the xy chromaticity coordinates in a 2 ° visual field and an average primary particle diameter of 45 nm; Isopropoxybis (acetylacetonato) titanium (Mitsubishi Gas Chemical Co., Ltd., trade name: TAA) 3 g and ethanol / 1-propanol mixed (volume ratio 50/50) containing 0.02% by mass of concentrated nitric acid in 37 g of solvent Was dispersed using a bead mill to prepare a dispersion A containing 20% by mass of ITO. The average dispersed particle size measured by the dynamic light dispersion method was 80 nm.

[Example 1]
Dispersion B was prepared by adding 2-butanol to dispersion A and diluting it so that the solid content concentration became 7% by mass. Dispersion B thus obtained was converted into an ultraviolet-absorbing green glass having a thickness of 5.0 mm (Tv: 72.5%, Te: 44.2%, infrared transmittance of wavelength 1 μm T1: 22%, infrared wavelength of 2 μm). transmittance T2: 49%, radio transmission loss _T LG at a frequency of 1 GHz: 0.95 dB, manufactured by Asahi Glass Co., Ltd., was applied by commonly known UVFL) spin coating onto, and in the air and dried for 10 minutes at 120 ° C. lower did.

  3.5% by mass of perhydropolysilazane (manufactured by AZ-Electronic Materials, trade name: Aquamica NV-110) and 1.2% by mass of tetra-n-butoxytitanium (manufactured by Matsumoto Pharmaceutical Co., Ltd., trade name: TA-) The xylene solution containing 25) was applied onto the lower layer by a spin coating method and dried in air at 120 ° C. for 10 minutes to form an upper layer.

  The glass with a coating obtained above was heat treated in an electric furnace in an air atmosphere maintained at 720 ° C. until the glass substrate temperature reached 685 ° C. to obtain a glass plate with an infrared shielding layer. The time required for the heat treatment was approximately 4 minutes.

Further, the abundance ratio of ITO and silicon oxide in the first layer was measured by X-ray photoelectron spectroscopy (XPS), and expressed by mass ratio, [ITO] / [silicon oxide] = 10/4. Further, when the composition analysis of the second layer was performed by secondary ion mass spectrometry, it was found that the main component is silicon oxide containing TiO ₂ , but silicon oxynitride containing nitrogen slightly.

Table 1 shows the properties of the obtained glass plate with an infrared shielding layer. In Table 1, the layer thickness 1 is the first layer thickness [nm], the layer thickness 2 is the second layer thickness [nm], and the layer thickness ratio is [second layer thickness] / [first layer thickness]. ], Tv-1 is the visible light transmittance [%] of the glass substrate alone, Tv-2 is the visible light transmittance [%] of the glass plate with an infrared shielding layer, and Tv-3 is the infrared shielding layer obtained by calculation. Visible light transmittance [%], T _LW -T _LG indicates a difference between T _LG and radio wave transmission loss T _{LW of the} glass plate with an infrared shielding layer at a frequency of 1 GHz.

[Examples 2 to 5]
A glass plate with an infrared shielding layer was produced in the same manner as in Example 1 except that the thickness of the first layer and the thickness of the second layer were changed as shown in Table 1. Table 1 shows the properties of the obtained glass plate with an infrared shielding layer.

[Example 6 (comparative example)]
A glass plate with an infrared shielding layer was produced in the same manner as in Example 1 except that the thickness of the first layer and the thickness of the second layer were changed as shown in Table 1. Table 1 shows the properties of the obtained glass plate with an infrared shielding layer.

  In Example 6, which is a comparative example of the present invention, it can be seen that the infrared shielding property is slightly lowered as compared with Examples 1-5.

[Examples 7 to 9 (reference examples)]
Except for changing the thickness of the first layer and the thickness of the second layer as shown in Table 2, when a glass plate with an infrared shielding layer was prepared in the same manner as in Example 1, the infrared shielding having the characteristics shown in Table 2 was made. A layered glass plate is obtained. The glass plates with infrared shielding layers of Examples 7 to 9 are slightly inferior in any of infrared shielding properties, radio wave transparency, visible light transmittance and transparency as compared with Examples 1 to 5.

  As described above, by setting the layer thickness of the first layer and the layer thickness ratio of the second layer / first layer within the scope of the present invention, the infrared shielding property, radio wave transmittance, visible light transmittance, and transparency can be achieved. It can be expressed in a balanced manner.

The heat insulating window plate of the present invention has high visible light transmittance, high radio wave transmission, and excellent mechanical durability, and is particularly expected to be used for applications such as automotive glass and glass for building materials. it can. In particular, the present invention can also be applied to parts that require extremely high durability, such as automobile door glass.

It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2005-118414 filed on April 15, 2005 are cited herein as the disclosure of the specification of the present invention. Incorporated.

Claims (8)

A transparent plate-like body and an infrared shielding layer comprising the following first layer and the following second layer provided on the surface of the transparent plate-like body (however, the first layer exists on the transparent plate-like body side) And
The transparent conductive oxide fine particles having an average primary particle diameter of 100 nm or less in the first layer are contained in a matrix mainly composed of silicon oxide in a mass ratio of [transparent conductive oxide fine particles] / [silicon oxide] = 10 / 20-10. And a layer having a thickness of 300 to 400 nm and dispersed at a ratio of 0.5, and the second layer is a layer containing silicon oxide,
And the layer thickness ratio of 2nd layer / 1st layer is 0.1-0.5. The plate-like body for heat insulation windows characterized by the above-mentioned.   The plate-like body for heat-insulating windows according to claim 1, wherein the thickness of the first layer is 300 to 330 nm.   The plate-like body for heat-insulating windows according to claim 1 or 2, wherein the second layer has a thickness of 80 to 140 nm.   The layer thickness ratio of 2nd layer / 1st layer is 0.2-0.5, The plate-like body for heat insulation windows in any one of Claims 1-3.   The visible light transmittance of the said infrared shielding layer is 90% or more, The plate-shaped body for heat insulation windows in any one of Claims 1-4.   The transparent plate-like body has a visible light transmittance of 70% or more, a light transmittance of 30 μm or less at a wavelength of 1.0 μm and a light transmittance of 40 μm at a wavelength of 2.0 μm as defined by JIS-R3212 (1998). It is a glass plate which has -70%, The plate-like body for heat insulating windows in any one of Claims 1-5.   The plate for an insulating window according to any one of claims 1 to 6, wherein the plate for an insulating window is a glass plate for an automobile window. The infrared shielding layer, a radio transmission loss _{T LW} thermally insulating window plate-like member at a frequency of 1GHz, the difference _T LW _{-T LG} with radio transmission loss _{T LG} of the transparent plate-shaped body at a frequency of 1GHz It is a layer used as 2 dB or less, The plate-like body for heat insulation windows in any one of Claims 1-7.

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