Coated products

Description: TECHNICAL FIELD [Detailed description of the invention]

The present invention relates to a method and application of a glass having a coating on the surface of the glass, which prevents the transfer of alkali metal ions from the surface of the glass, and a related product using such a coaching glass. It is known that as a result of the transfer of alkali metal ions from the glass surface to the inside of the coaching, the coaching applied to the glass surface may deteriorate. For example, UK Pat. No. 705,934 describes the phenomenon of clouding of transparent conductive coaching on soda coal quartz glass. This fogging phenomenon could be reduced by removing alkali metal ions from the glass surface prior to the conductive coaching treatment, or also by removing silica, titanium oxide, etc. before the conductive coaching treatment. It could also be reduced by adding it as an interlayer film. The silica film is first finished by reacting silicon tetrachloride, silicon tetrabromide or silicon chloroform, which has been made into a volatile non-aqueous solution, with glass, exposing the coaching to the atmosphere to dry it, and then polishing it until the coaching surface shines. Alternatively, a silica film can also be formed by immersing the glass plate in a solution of a partially hydrolyzed silicic acid ester, such as ethyl orthosilicate, and then drying. Similarly, European Patent No. EP0071865A3 is also concerned about the phenomenon that the conductive coating of soda coal quartz glass becomes cloudy as a result of alkali metal ions diffusing on the glass surface and reacting with the epidermis layer that is easily attacked by alkali metals. Is shown. It is stated in this specification that the conductive layer becomes cloudy, the transparency decreases, the electrical resistance increases, and the physicochemical durability decreases as a natural result of such diffusion. There is. Furthermore, as a result of the diffusion of alkali metal ions from the glass support, performance deterioration of liquid crystal display devices, electrochromic devices, amorphous silicon photovoltaic cells, etc. is also mentioned. In this type of device, a conductive layer such as indium tin oxide is generally coated on the glass, but European Patent EP0071865A3 states (direct alkali metal ions on the conductive layer). It also describes the effects that result from the reaction of alkali metal ions with the epidermis layer that covers the conductive layer. European Patent EP0071865A3 proposes a method of blocking the diffusion of alkali metal ions from a glass support using a barrier layer of silicon oxide containing hydrogen bound to silicic acid. To form the barrier layer, a vacuum vapor deposition method, a sputter method, an ion plating method, a sol / gel method, a chemical vapor deposition method, or the like is possible. The chemical vapor deposition methods disclosed herein are O.D. under oxidation conditions at temperatures of 300-550 ° C.₂: SiH₄Oxygen gas and monosilane gas (SiH) such that the ratio is 10: 1 to 60: 1.₄), This is a method of depositing a silicon oxide layer on the glass surface. British Patent No. 2,031,756B states that a layer of metal oxide containing silicon oxide is used as a color damping layer to reduce the pearl luster that appears when the glass is coated with infrared reflection of semiconductor metal oxide. It is stated that it will be used. As the semiconductor metal oxide, fluorine-added tin oxide may be used, but in the above specification, diffusion of alkali metal ions from the glass is blocked, which causes cloudiness in the layer continuously deposited on the tin oxide layer. It also describes the known effects of amorphous silicon oxide layers that are effective in avoiding this. The color attenuation layer described in UK Pat. No. 2,031,756B has a refractive index of 1.7 to 1.8 and a thickness of 64 to 80 nm. The layer containing silicon oxide is formed by chemically thin-filming on heated glass at 300 to 500 ° C. using silane in the presence of an oxidizing gas. British Patent No. 1,507,465 discloses a method of applying silicon reflection coating to flat glass in order to produce sunlight-suppressing glass having an aesthetically pleasing silver mirror reflection color. In this method, silane gas is sent to a high temperature region that opens toward the glass surface, the high temperature region is maintained under non-oxidizing conditions, and the pyrolyzed silane is vapor-deposited as reflective silicon coating on the glass surface. It is a law. UK Pat. No. 1,573,154 discloses improvements to the method of making reflective solar-suppressed glass described in the preceding specification No. 1,507,645. According to this improved method, the addition of a gaseous electron donor, such as ethylene, to the silane-containing gas has the unexpected effect of increasing the resistance of the coaching glass to erosion by external alkalis. The ratio of the electron donor to the silane is generally 0.1 to 2.0, preferably 0.2 to 0.5. However, in this specification, a case where the ratio is 2.5 or more, for example, 5 is also mentioned, and in such a case, an alkali-resistant silicon coaching with extremely high abrasion resistance can be obtained. , The high reflectance for visible light obtained without the use of electron donors is sacrificed. Such coaching is used for architectural glass, and as an example, a method of coaching 6 mm thick soda-coal quartz glass in both the float method and the roll forming method is described. .. Analysis of the coaching using ethylene as the electron donor revealed that the coaching contained some oxygen despite the treatment under non-oxidizing conditions. The inventor added a high proportion of electron donors as described in British Patent No. 1,573,154 to create a thin transparent coaching that contained oxygen transferred from the glass. Even more surprisingly, we found that this coaching was effective as a barrier to the transfer of alkali metal ions from the glass surface. The coaching glass thus obtained is very effective for the epidermis layer (whether it is directly coated on the barrier film or coated via an intermediate layer) that easily reacts with alkali metal ions. Is. The present invention (1) thermally decomposes silane gas on a glass surface above 600 ° C in the presence of a gaseous electron donor and results in at least 75% when present on clear float glass with a thickness of 6 mm or less. A transparent barrier coating with a thickness of 50 nm or less containing silicon and oxygen, which provides a coating glass showing the light transmittance of the glass, is formed on the glass surface by the cooperation of silicon from silane gas and oxygen from the glass. (2) Next, the coaching glass is coated with a layer in which alkali metal ions are easily diffused from Agulhas. The present invention provides a coaching method for an alkali metal ion-encapsulating glass including the above. As a coating layer that is easily attacked by alkali metal ions diffused from glass, there is a light-transmitting layer formed by doping with a metal oxide. An electron donor is a substance containing an electron, whether it is a bound electron or a lone pair of electrons, and which donates an electron to the electronic structure of an appropriate electron acceptor molecule. Examples of electron donors containing bound electrons include unsaturated hydrocarbons, especially olefins (alkenes) and acetylenes (alkynes). For example, ethylene, butagen, pentene, difluoroethylene and acetylene (C)₂H₂). Further, aromatic hydrocarbons such as benzene and xylene can be given as examples. Next, examples of electron donors containing donor electrons in the form of lone electron pairs include ethers, amines, aldehydes, ketones, alcohols, hydrides of nitrogen, carbon monoxide and carbon monoxide. In terms of convenience, an electron donor that is gaseous under normal ambient conditions is convenient. However, even electron donors that do not meet this condition can be used without much difficulty if the vapor pressure at 60 ° C is at least 5 kPa. As a result of using an electron donor, the mode of the reaction is unknown, but it was found that oxygen from the glass and silicon from the silane cooperate to form a transparent barrier coaching on the glass. did. The detailed mechanism of the reaction has not yet been elucidated, but it is certain that the electron donor is absorbed on the glass surface. Thus, despite the fact that the pyrolysis is carried out in a gas that does not contain any oxygen, a transparent coaching containing silicon and oxygen coming out of the glass is obtained, which has light reflectivity. It is different from silicon coaching. The rate at which oxygen-containing chemical species are transferred from the glass depends on the temperature of the glass. Therefore, in order to increase the utilization rate of oxygen-containing species from glass, coaching may be performed at a glass temperature of 600 ° C. or higher. It is not necessary to obtain all of the oxygen in the clear barrier coating from the glass, some of which may be obtained from the electron donor. Even after the coaching process is complete, exposure of the coached glass to atmospheric oxygen causes some oxidation. However, it is preferable to use an oxygen-free electron donor, or an electron donor that is generally considered to be reducing even if it contains a certain amount of oxygen, such as carbon monoxide or alcohol. In general, the oxygen-containing gas reacts with the silane before it reaches the hot glass surface, forming a powdered adhesion layer of silicon oxide. Therefore, it is wise to avoid the use of oxygen-containing gases. In particular, those in which oxygen is present in the form of molecules should be avoided. The electron donor as a preferred embodiment of the present invention is oxygen-free. Examples of oxygen-free electron donors suitable for use include unsaturated hydrocarbons, aromatic hydrocarbons, amine and nitrogen hydrides. Due to the limited amount of oxygen-containing species obtained from glass, there is a limit to the thickness of transparent coaching made with oxygen-free electron donors. By the way, the present invention is a transparent barrier coaching containing silicon and oxygen, and in particular, 50 nm (nanometer 1 nm = 10).^-9It is related to transparent barrier coaching with a thickness up to m). The ratio of electron donor to silane required to make a transparent coaching depends on the particular electron donor used, but the ratio of the electron donor to silane is until the desired light transmissive coaching is achieved. It can be easily obtained by a simple experiment of increasing the ratio. Suitable ratios of gaseous electron donors to silanes are generally in the volume ratio range of 0.5: 1 to 15: 1. When olefins were used, it was found that the best results were obtained when the olefin: silane ratio was 3: 1 to 10: 1. Excessive use of certain oxygen-free electron donors with respect to silanes has been found to inhibit the formation of coaching. Therefore, such overuse should be avoided. The rate of overuse depends on the type of electron donor used, which can be easily determined by a simple experiment. The transparent barrier coating according to the present invention is made in the absence of free oxygen or a compound generally regarded as an oxidizing agent. By doing so, even if barrier coating is applied to the strip-shaped float glass while the float glass is progressing on the molten metal bath for manufacturing flat glass, the inconvenient danger that the molten metal is oxidized is avoided. it can. Coaching is recommended when the glass temperature is in the range of 600 to 750 ° C. In particular, a glass temperature in the range of 600 to 700 ° C is suitable. Barrier coaching can be performed using laminar flow plate glass manufacturing methods and equipment as disclosed in UK Pat. No. 1,507,465. Preferably, monosilane is selected as the silane to be used, and this may be mixed with an inert gas such as nitrogen. The coaching used in the present invention is extremely effective as a blocking barrier against the migration of alkali metal ions, exerts an excellent effect even with a coaching having a thickness of 15 nm, and maintains its effectiveness as a barrier even with a thinner coaching having a thickness of 5 nm or less, for example. ing. High transparency may be required depending on the application. In such a case, since the coaching is coated on a transparent float glass having a thickness of up to 6 mm, it is preferable to have a light transmittance of at least 80%. Further, for certain applications, it is desired that the barrier coaching itself has sufficient resistance to external alkalis. The inventor has found that coaching made with an electron donor, which is an organic substance, contains a considerable amount of carbon and exhibits excellent durability against erosion by external alkalis. After the barrier coaching is vapor-deposited, a skin layer that is easily attacked by alkali metal ions diffused from the glass is coated on the barrier coaching. This type of layer coats the coated surface with a liquid or solid reactant by a well-known method such as sputtering, chemical deposition or spraying. The barrier-coated glass according to the present invention is used when it is inconvenient for alkali metal ions to diffuse from a glass containing alkali metal ions to a skin layer that is easily attacked by alkali metal ions. In this case, it does not matter whether the epidermis layer, which is vulnerable to alkali metal ions, is tangently coated on the barrier coaching or is coated via the intermediate layer. As the epidermis layer, there are many coachings of metal oxides that transmit light and have electrical conductivity. This type of coaching suitable for commercial applications generally has a surface electrical resistance of 500 Ω / or less, but some applications require a smaller surface electrical resistance, for example 50 Ω / or less. In such a case, a coaching having a surface electrical resistance as small as possible and having sufficient optical properties is adopted. According to the previously cited European Patent EP0071865A3, this type of coaching is prone to deterioration due to the diffusion of alkali metal ions from the glass support as a coating substrate, reducing light transmission and electricity. The conductivity also decreases. An example of a metal oxide that has both light transmission and conductivity is a doped metal oxide, which includes indium oxide doped with tin, which is usually deposited on the surface by sputtering. Doping of tin oxide, especially tin oxide with added fluorine, is treated by sputter deposition, chemical deposition, or solution or powder spray. The thickness of the conductive layer depends on the required electrical conductivity, but is usually in the range of 50-1500 nm. Transparent conductive metal oxides, such as tin-added indium oxide and fluorine-added tin oxide, usually reflect infrared radiation and are therefore excellent as window glass coaching that reflects heat into the building. When this type of coaching is used as an infrared reflective coating, it generally has a thickness in the range of 200-1000 nm. Thus, according to another aspect of the present invention, the silane gas is thermally decomposed on the glass surface of 600 ° C. or higher in the presence of the gaseous electron donor, and is present on the transparent float glass having a thickness of 6 mm or less. An alkali metal formed by the collaboration of silicon from silane gas and oxygen from glass to a transparent barrier coating with a thickness of 50 nm or less containing silicon and oxygen, resulting in a coating glass showing at least 75% light transmission. Provided is a flat glass formed by further coating a layer on which an alkali metal ion is easily diffused from the glass on a glass substrate containing ions. Desirably, the layer in which the alkali metal ions are easily diffused is a conductive flat glass composed of a conductive metal oxide layer on the transparent barrier coating having a surface electrical resistance of 500 Ω / or less. The conductive metal oxide coating layer can be provided with light transmission, and a doped metal oxide may be used for this. Similarly, the present invention thermally decomposes silane gas on a glass surface above 600 ° C in the presence of a gaseous electron donor and results in at least 75% when present on clear float glass with a thickness of 6 mm or less. A transparent barrier coating with a thickness of 50 nm or less containing silicon and oxygen is formed on a glass substrate containing alkali metal ions in collaboration with silicon from silane gas and oxygen from glass. Further, the present invention provides an infrared reflective flat glass provided by further forming a light-transmitting and infrared-reflecting metal oxide-doped layer as a layer in which alkali metal ions are easily diffused from the glass. Barrier-coached glass is even more advantageous when used in complex structures. For example, it is used as a support for a conductive metal oxide film in a liquid crystal display device. This device consists of a liquid crystal material interposed between two opposing conductive layers and an orientation layer arranged on each conductive layer, and at least one of the conductive layers has light transmission. A layer, which is supported on glass with barrier coating between the conductive layer and the glass. In such cases, barrier coating not only prevents the conductive metal oxide layer from being directly corroded by the alkali metal ions from the glass, but also allows the alkali metal ions to pass through the conductive metal oxide layer to the liquid crystal. It also prevents the diffusion into the material, resulting in unwanted electrochemical reactions. The transparent barrier coating also serves as a skin layer for amorphous silicon solar electrons, that is, when alkali metal ions diffuse from the glass surface into amorphous silicon, the efficiency of the battery is significantly impaired. The barrier coaching according to the present invention is extremely effective in suppressing the transfer of alkali metal ions. Moreover, since this barrier coaching is effective even if it is very thin, it can also be used as a barrier coaching applied to glass having a high visible light transmittance. Moreover, since this coaching uses oxygen emitted from the glass, it can be manufactured without requiring strong oxidation conditions. Therefore, this coaching is suitable for online industrial production as the float glass strip progresses over the float bath. According to the present invention, when the transparent barrier coaching applied using ethylene was measured with an infrared spectrometer to make the presence of Si-H bonds different, the absorption of infrared rays corresponding to the Si-H bonds was detected. Was not done. Hereinafter, examples of the present invention will be described, but it goes without saying that the present invention is not limited to the examples. Unless otherwise noted, gas capacity is a value measured under standard ambient conditions, i.e. at about 20 ° C, 1 atm. [Examples 1 to 4] A 6 mm thick float glass strip was covered with barrier coaching over a width of 3 m. This is 50 of the gas with 10% monosilane added to 90% nitrogen as the float glass strip progresses over the float bath, as described in UK Pat. No. 1,507,996. This was done by passing a mixed gas of a / min flow rate and a further 10 / min flow rate of ethylene parallel to the surface of the glass in a laminar flow state. The temperature of the glass at the coaching station was 625 ° C, and the layer speed of the glass strip was 370 m / hr. Then, the ethylene flow rate was increased, and the ethylene flow rate was increased to 20, 30, 40, and 50 / min, respectively, and barrier coaching was performed. Table 1 shows the ethylene: silane ratio used in the coaching gas and the measurement results of the resulting coaching. As a result of using ethylene, the reflectance of light decreased, and when the ethylene: silane ratio was increased to 4: 1, the light transmittance increased sharply. When the ethylene: silane ratio was further increased, the light transmittance increased, but the increase was slow. The effectiveness of coaching as a barrier to the transfer of alkali metal ions from the glass surface was measured as follows. Cut two samples of coaching glass into 10 cm squares, sandwich an annular ring of silicon rubber with an inner diameter of 8.5 cm between them, and tighten them.<img file="JP2585514B2_D0001.tif" />A cylindrical cell with an inner wall defined by a surface was created. After passing through the hole of the rubber ring and filling the cell with deionized water, the hole was closed and the sealed cell was immersed in a hot water bath at 96 ° C for 48 hours. The solution was taken out and sodium analysis was performed by flame light emission spectroscopy. Measure the amount of sodium extracted, 10 cm of glass exposed to water in the cell²Every Na₂The amount of O was determined in micrograms (μg). Experiments were also conducted on a large number of commercially available soda-coal quartz glass having a silica-based ion-blocking surface layer. The result is 60 μg Na₂O / dm²From 1000 μg Na₂O / dm²The measured values up to the range exceeding the above were obtained. We also inspected so-called alkali-free (alkali-free) glass, which is a commercially available non-coaching glass, and found that it was 13 μg Na.₂O / dm²It was the result of. The coaching glass used in the present invention is superior to the commercially available alkaline-free glass, and since it is difficult to apply the online coaching method of float glass, it is also excellent to the coaching glass treated by the offline method. It became clear. The product of Example 3 was analyzed by ESCA (Electron Spectroscopy for Chemical Analysis). In this method, the surface to be analyzed is first irradiated with X-rays, and then the energy spectrum of the primary electrons emitted from the surface is measured to qualitatively and quantitatively detect the elements present on the surface. Then, the atomic layer on the surface is removed by argon etching, the next atomic layer is exposed, and the above qualitative and quantitative analysis is performed again. Repeat etching and analysis to examine the surface layer composition to a depth that exceeds the thickness of the coaching. The results obtained for the product of Example 3 are shown in the following table.<img file="JP2585514B2_D0002.tif" /> It can be seen that the coaching contains silicon, oxygen and carbon. The oxygen: silicon ratio on the coaching surface is about 3: 2. This ratio drops to 1: 1 after 900 seconds of etching, but then rises. The carbon concentration is 45% on the surface, but varies around 20% inside the coaching. [Examples 5 and 6] A strip of float glass with a thickness of 2 mm was coated with a transparent barrier coating of silicon and oxygen. This is because, as described in British Patent No. 1,507,996, a mixed gas of monosilane, nitrogen and ethylene is applied to the surface of the glass in a laminar flow state as the strip of float glass progresses through the float bath. This was done by passing in parallel. The temperature of the glass at the coaching station was 660 ° C, and the layer speed of the glass strip was 1030 m / hr. Table 2 shows the properties of the obtained product and the gas flow.<img file="JP2585514B2_D0003.tif" /> The resulting coaching had effective ion blocking properties. The light transmittance increased with the ethylene: silane ratio, and when the ratio was 3.3: 1, the transmittance was 84.9%. A calculation of the light transmittance of 1 mm thick glass with similar coaching should be 85.4%, compared to 91.4% of 1 mm thick glass without coaching. .. [Examples 7 to 9] A band of float glass with a thickness of 1.3 mm was coated with a barrier of silicon and oxygen. This is the surface of the glass in a laminar flow state with a mixed gas of monosilane, nitrogen and ethylene as the strip of float glass travels over the float bath, as described in British Patent No. 1,507,996. It was done by passing in parallel with. The temperature of the glass at the coaching station was 640 ° C, and the layer speed of the glass band was 1200 m / hr. Table 3 shows the properties of the obtained product and the gas flow.<img file="JP2585514B2_D0004.tif" /> The ion blocking performance (measured by the alkali metal ion extraction test) was not as remarkable as in the above-described embodiment, but it is still comparable to commercially available glass and sufficient for normal commercial use. This product shows high light transmittance (about 90%). [Examples 10 to 13] In the laboratory, a still sample of 4 mm thick float glass was coached. This was done by passing a coaching gas consisting of a mixture of nitrogen, monosilane at a concentration of 10% in nitrogen, and a gaseous electron donor (EDC) over the surface of the heated glass. Table 4 shows the composition of the coaching gas used, the temperature and deposition time of the glass, and the properties of the obtained coaching glass. The use of other electron donors instead of ethylene should result in clear coaching with similar ion blocking properties. The coaching is transparent and contains silicon and oxygen derived from the glass. [Examples 14 to 16]<img file="JP2585514B2_D0005.tif" /> In the laboratory, a still sample of 4 mm thick float glass was coached. This is a mixed gas coating gas consisting of a flow rate of 6.6 / min of nitrogen, a flow rate of 0.4 / min of monosilane 10% by volume in nitrogen, and a flow rate of 0.4 / min of ethylene, on a heated glass surface. This was done by passing at a temperature of ° C for 10-40 seconds. Table 5 shows the time used and the properties of coaching obtained. The measured light reflectance of the coaching glass increases with the coaching time. The coaching obtained after 80 seconds is seemingly similar to the reflective coaching made with a very small proportion of ethylene. Through this series of experiments, the following was found. That is, as the coaching time becomes longer and the thickness of the coaching increases, the oxygen obtained from the glass is used up and the transparency of the vapor deposition coaching is lost. This is an early transparent coaching containing oxygen and silicon coming out of the glass.<img file="JP2585514B2_D0006.tif" />It seems that the cause is that non-silicon oxide is deposited on the top. All the coachings tested were immersed in a 1N NaOH aqueous solution at 80 ° C and tested for durability against external alkaline corrosion. After 50 minutes, there were no visible signs of corrosion in any case. [Examples 17 to 33] In the laboratory, a still sample of 4 mm thick float glass was coached. This was done by passing a coaching gas over the surface of the heated glass at 630 ° C. Table 6 shows the composition of the coaching gas used, the coaching time, and the properties of the obtained coaching product. In each case, the ratio of electron donor to silane in the gas state was adjusted to a ratio suitable for making transparent coaching. [Example 34] Samples made in the same manner as in Examples 1 to 4 with an ethylene to silane ratio of 5: 1 and float glass with a thickness of 6 mm and no coaching.<img file="JP2585514B2_D0007.tif" />The sample was coated with fluorinated tin oxide. Ammonium difluorotetrachlorostanate (NH₄)₂SnCl₄F₂Is crushed to a particle size of 50 μm or less and dispersed in an air stream. Then, the air flow containing the dispersed powder is applied to the surface of the glass 1 m.²It was sprayed onto a glass sample heated at a temperature of 580 ° C at a rate of 80 g per unit. The thickness and electrical resistance of the fluorine-added tin oxide coating thus produced were measured. The measurement results were as follows.<img file="JP2585514B2_D0008.tif" /> The extremely low electrical resistance of the coaching on the barrier-coated support is effective as a barrier coaching that prevents alkali metal ions, which have a detrimental effect on the electrical resistance of the tin oxide layer, from migrating from the glass. It shows that there is. [Example 35] A liquid crystal display device as described above was produced by using glass subjected to transparent barrier coaching as a support in the same manner as in the case of Example 8. Then, when a durability test was conducted, it was found that the product had a life of more than 1,000 hours at a temperature of 60 ° C and a relative humidity of 95%. The electron donors used in each example all have a vapor pressure of 760 mm or more at 60 ° C, with the following exceptions. The vapor pressure at 60 ° C of the above exception is as follows.<img file="JP2585514B2_D0009.tif" />