JP2011079685A - Coating material for glass producing vessel, burnt coated film for glass producing vessel made of the burnt coating material, glass producing vessel with the burnt coated film, glass producing apparatus with the glass producing vessel and glass producing method using the glass producing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently suppress the generation of bubbles caused by water present in a glass melt. <P>SOLUTION: A coating material for a glass producing vessel to form a burnt coated film for the glass producing vessel includes a vessel body comprising a noble metal or a noble metal-containing alloy and a burnt coated film formed on the surface of the vessel body. The coating material for the glass producing vessel contains a glass component, alumina fine particles having an average particle diameter of 5-50 nm and an Si component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coating material for a glass production container, a fired coating film for a glass production container formed by firing the glass, a glass production container provided with the same, a glass production apparatus provided with the same, and a method for producing glass using the same. Specifically, the present invention is for a glass production container for forming a fired film of a glass production container comprising a container body made of a noble metal or an alloy containing a noble metal and a fired film formed on the surface of the container body. The present invention relates to a coating material, a fired film for a glass production container formed by firing the coating material, a glass production container provided with the coating material, a glass production apparatus provided with the same, and a glass production method using the same.

  Conventionally, as a glass production container for producing high-quality glass such as optical glass and display glass, a glass production container made of a noble metal such as Pt or an alloy containing a noble metal (hereinafter referred to as “noble metal container”). Is used. The reason is that the noble metal container has high rigidity even in a high temperature atmosphere of 1000 ° C. or higher, and hardly contaminates the internal glass.

  However, when a noble metal container is used for melting glass, bubbles due to moisture in the glass may be generated on the surface of the container on the molten glass side. The reason why this bubble is generated is that oxygen generated by the decomposition of water contained in the glass passes through the noble metal container and is released to the outside, so that the oxygen concentration of the molten glass located near the surface of the noble metal container It is thought that this is because of an increase. That is, while hydrogen generated by the reaction shown in the following formula (1) permeates the noble metal container and is released to the outside, oxygen that cannot permeate the noble metal container is dissolved in the molten glass located near the surface of the noble metal container. Thus, it is considered that the oxygen concentration of the molten glass located near the surface of the noble metal container increases and bubbles are generated.

OH ⁻ → 1 / 2O ₂ + 1 / 2H ₂ + e ⁻ (1)
In view of such a problem, for example, in the following Patent Documents 1 to 4, when a container made of Pt or an alloy containing Pt (hereinafter referred to as “Pt container”) is used, it is caused by moisture in the glass. A method for suppressing the generation of bubbles is proposed.

  For example, in Patent Document 1 below, by controlling the partial pressure of hydrogen outside the Pt container with respect to the partial pressure of hydrogen inside the Pt container at the time of glass production, bubbles caused by moisture in the glass are controlled. A method for suppressing the occurrence has been proposed.

  In the following Patent Documents 2 and 3, a method for suppressing the generation of bubbles due to moisture in the glass by reducing the hydrogen permeability of the Pt container by applying a glass barrier coating to the outer surface of the Pt container is proposed. Has been.

  Moreover, in the following patent document 4, generation | occurrence | production of the bubble resulting from the water | moisture content in glass is suppressed by coat | covering the outer surface of a Pt container with the coating material containing the refractory component containing an alumina and a silica, and a glass component. A method has been proposed. In Patent Document 4, alumina particles are listed as an example of alumina contained in the coating material. The average particle diameter of the alumina particles is preferably 1 to 100 μm.

Special table 2001-503008 gazette JP-T-2004-523449 JP 2006-522001 Gazette WO2006 / 030737 A1

  If it is going to suppress generation | occurrence | production of the bubble resulting from the water | moisture content in glass by the method of said patent document 1, it is necessary to continue supplying hydrogen during glass melting. For this reason, there exists a problem that the manufacturing cost of glass rises. Also, if the hydrogen partial pressure outside the Pt container is too high, hydrogen will pass through the Pt container from the outside of the Pt container and enter the Pt container and melt into the glass melt, which may cause hydrogen bubbles. There is. Therefore, there is a problem that it is difficult to sufficiently suppress the generation of bubbles in the glass melt.

  As described in Patent Documents 2 and 3, when a glass barrier coating layer is formed on the outer surface of the Pt container to suppress the generation of bubbles due to moisture in the glass, hydrogen is generated during glass melting. It is not always necessary to continue to supply. However, as a result of intensive studies by the inventors, it has been found that even when a glass barrier coating layer is formed on the outer surface of the Pt container, the generation of bubbles may not be sufficiently suppressed. That is, there is a problem that bubbles cannot be sufficiently suppressed by simply forming a glass barrier coating layer on the outer surface of the Pt container.

  As described in Patent Document 4, when the outer surface of the Pt container is coated with a coating material containing a glass component and a refractory component including alumina particles and silica particles, as described in Patent Documents 2 and 3. In addition, a higher hydrogen barrier property can be obtained than when a barrier coating layer made of a glass component is formed. Therefore, generation | occurrence | production of the bubble resulting from the water in a glass melt can be suppressed effectively.

  However, in recent years, the bubble quality required for high-quality glass such as optical glass and display glass has been increasing year by year, and there is a desire to further suppress the generation of bubbles due to water in the glass melt.

  This invention is made | formed in view of this point, The objective is to fully suppress generation | occurrence | production of the bubble resulting from the water which exists in glass melt.

  A coating material for a glass manufacturing container according to the present invention is for forming a fired film of a glass manufacturing container comprising a container body made of a noble metal or an alloy containing a noble metal, and a fired film formed on the surface of the container body. The present invention relates to a coating material for glass manufacturing containers. The coating material for glass production containers according to the present invention includes a glass component and alumina fine particles having an average particle diameter in the range of 5 nm to 50 nm. The coating material for glass production containers according to the present invention contains a Si component.

  The fired film for glass production containers according to the present invention is a fired film formed by firing the coating material for glass production containers according to the present invention. The fired coating for a glass production container according to the present invention preferably contains mullite crystals.

  As described above, the coating material for glass production containers according to the present invention includes alumina fine particles containing an Si component and having an average particle diameter in the range of 5 nm to 50 nm. For this reason, by baking the coating material for glass manufacturing containers, the Si component and the alumina fine particles react with each other, and mullite crystals are efficiently generated. This mullite crystal is excellent in heat resistance. For this reason, the fired film for glass manufacturing containers obtained by baking the coating material for glass manufacturing containers is excellent in heat resistance. In addition, even in a high temperature atmosphere, it is possible to effectively suppress the dropping or outflow of the glass component that suppresses the permeation of hydrogen from the fired coating for a glass production container. Therefore, by using the fired coating for a glass production container formed by firing the coating material for a glass production container according to the present invention, hydrogen in the molten glass permeates to the outside of the glass production container. It is possible to effectively suppress the generation of bubbles over a long period of time. In particular, it is effective for a long period of time that bubbles are generated in the molten glass even in a high temperature atmosphere by using a fired coating for a glass production container formed by firing the coating material for a glass production container according to the present invention. Can be suppressed.

  Patent Document 4 describes that, unlike the present invention in which alumina fine particles are contained in the coating material, alumina particles having an average particle diameter larger than that of the alumina fine particles are contained in the coating material together with silica. In the invention described in Patent Document 4, the crystalline metal oxide such as alumina particles is used for suppressing deformation of the fired film and low melting point components such as a glass component contained in the fired film from dripping from the fired film. The range of the preferable average particle diameter of the alumina particles, which is a component, is set to a relatively large value of 1 μm to 100 μm. However, when only alumina particles having a large average particle diameter of 1 μm to 100 μm are used, the reaction between the alumina particles and the glass component is slow, and the glass component reacts with the alumina particles before the glass component is firmly fixed. The glass component that suppresses the permeation of hydrogen gas from the fired coating may fall off or flow out.

  In contrast, in the present invention, alumina fine particles having a small average particle diameter of 5 nm to 50 nm are used. For this reason, when a coating material is baked and the baked film for glass manufacturing containers is formed, an alumina fine particle and a glass component react efficiently and rapidly, and the mullite which has high heat resistance precipitates. Accordingly, it is possible to obtain a fired coating for a glass production container that more effectively suppresses the glass component from falling off or outflowing from the fired coating and has high heat resistance that is stable over the long term.

  When the average particle diameter of the alumina fine particles included in the coating material is less than 5 nm, the alumina fine particles are likely to aggregate, and the presence of the fine alumina particles having a small particle diameter is reduced, so that mullite is not efficiently generated. Further, in the thickness direction of the film, there is a portion in which the glass component that suppresses the permeation of hydrogen is not present in the fired coating (the glass component is sparse), and the hydrogen shielding ability may be reduced.

  Even when the average particle diameter of the alumina fine particles exceeds 50 nm, the presence of fine alumina particles having a small particle diameter is reduced, so that mullite is not efficiently generated.

In the present specification, “average particle size” means D ₅₀ (volume-based average particle size), which is measured by a laser diffraction / scattering particle size distribution analyzer (SALD-2000J manufactured by Shimadzu Corporation). Value.

  From the viewpoint of effectively generating mullite, it is preferable to increase the content of alumina fine particles in the coating material. However, when the content of the alumina fine particles in the coating material is excessively increased, the content of the glass component having an effect of shielding hydrogen tends to decrease. Accordingly, the content of the alumina fine particles in the coating material is preferably 0.1% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and 3% by mass to 15% by mass. More preferably.

“Mullite” is a silicic acid that is stable at high temperatures and is represented by a chemical composition formula in the range of Al ₂ O ₃ .nSiO ₂ (where n is in the range of 1/3 to 2/3). It is an aluminum compound. Therefore, from the viewpoint of effectively generating mullite, it is preferable that the coating material contains Si at least 1/6 times as much as Al contained in the alumina fine particles in terms of molar ratio.

  For example, the Si component contained in the coating material may be contained in the glass component, may be added separately as a component other than the glass component, or contained in the glass component, and other than the glass component. It may be added separately as a component.

  When the Si component is added to the coating material separately from the glass component, metallic silicon may be added, but is preferably added as silica. Specific examples of the silica to be added include silica particles and colloidal silica. From the viewpoint of effectively generating mullite, it is preferable that the average particle diameter of the silica to be added is small. Therefore, for example, it is preferable to add silica particles having an average particle diameter of 50 μm or less, and it is more preferable to add silica particles having an average particle diameter of 10 μm or less. Moreover, it is more preferable to add colloidal silica. In the present specification, “colloidal silica” refers to a liquid in which silica fine particles having an average particle diameter of 1 nm to 30 nm are dispersed in a dispersion medium.

  Colloidal silica also functions as an inorganic binder. For this reason, by adding colloidal silica to the coating material, a dense fired film can be obtained and the adhesion and adhesion strength of the fired film to the glass production container body can be increased. Therefore, it can suppress effectively that a baked film peels or falls off from a glass manufacturing container main body.

  In the present invention, the glass component is a component that suppresses the permeation of hydrogen. For this reason, from the viewpoint of obtaining a higher permeation suppression effect of hydrogen, a higher glass component content in the coating material is preferable. However, when the content of the glass component is too large, the content of components such as mullite (hereinafter referred to as “refractory component”) in the fired coating tends to decrease. Therefore, from the viewpoint of improving the heat resistance and durability of the fired coating for a glass production container, it is preferable that the content of the glass component is small.

  Therefore, the content of the glass component in the coating material is usually preferably in the range of 10% by mass to 80% by mass. However, the suitable range of the glass component content in the coating material varies depending on characteristics such as the softening temperature of the glass component used, the type and characteristics of the refractory component (= filler component) used, the temperature range used, and the like. For example, when the softening temperature of the glass component is high, the glass component is less likely to drop out or flow out. For this reason, the preferable content of the glass component in a coating material increases. On the other hand, when the softening temperature of the glass component is low, the glass component tends to fall off or flow out. For this reason, the preferable content of the glass component in a coating material decreases.

  Moreover, when the kind of refractory component with a high effect with respect to the long-term stability of a baked film is used, the preferable content of the glass component in a coating material increases. On the other hand, when a kind of refractory component having a low effect on the long-term stability of the fired film is used, the preferable content of the glass component in the coating material is reduced.

  Further, when the use temperature, that is, the temperature at the time of melting the glass is high, the glass is likely to fall off or flow out. For this reason, the preferable content of the glass component in a coating material decreases. On the other hand, when the operating temperature is low, the glass is less likely to drop out or flow out. For this reason, the preferable content of the glass component in a coating material increases.

  Therefore, the more preferable content of the glass component in the coating material should be appropriately set according to characteristics such as the softening temperature of the glass component used, the type and characteristics of the refractory component used, the temperature range used, and the like.

  For example, when the use temperature of the fired coating for a glass production container is in the range of 1000 ° C. to 1250 ° C., the preferable glass component content is usually 35% by mass to 80% by mass. The preferred glass component content when the operating temperature of the fired coating for a glass production container is in the range of 1250 ° C. to 1450 ° C. is usually 20% by mass to 60% by mass. The preferable glass component content is usually 10% by mass to 40% by mass when the use temperature of the fired coating for a glass production container is in the range of 1450 ° C to 1600 ° C.

  Although the kind of glass component used in this invention is not specifically limited, As mentioned above, it is preferable to use a glass component with a high softening temperature from a viewpoint of suppressing the omission and outflow of a glass component effectively. Specifically, it is preferable to use a glass component having a softening temperature of 800 ° C. or higher, more preferably a glass component having a softening temperature of 850 ° C. or higher, and more preferably a glass component having a softening temperature of 900 ° C. or higher. Specific examples of the glass component having a high softening temperature include borosilicate glass and silicate glass. Among them, it is more preferable to use borosilicate glass or silicate glass having a low content of alkali components such as Na, K, Li, and alkaline earth components such as Ba, Sr, and Ca as glass components. Furthermore, it is more preferable to use a silicate glass having a small content of an alkaline component such as Na, K, Li, or an alkaline earth component such as Ba, Sr, or Ca as the glass component. It is more preferable to use a so-called alkali-free glass component which does not contain.

For example, the composition range of the preferable glass component when the operating temperature of the fired coating for a glass production container is in the range of 1000 ° C. to 1250 ° C. is SiO ₂ 40 to 70 mass%, Al ₂ O ₃ 1 to 30 mass%. , B ₂ O ₃ 1-30% by mass.

For example, when the use temperature of the fired coating for a glass production container is in the range of 1250 ° C. to 1450 ° C., the preferable composition range of the glass component is SiO ₂ 50 to 70 mass%, Al ₂ O ₃ 5 to 30 mass%. , B ₂ O ₃ 1-20% by mass.

For example, when the use temperature of the fired coating for a glass production container is in the range of 1450 ° C. to 1600 ° C., the preferred composition range of the glass component is 50 to 75% by mass of SiO _{2 and} 10 to 30% by mass of Al ₂ O _3. , B ₂ O ₃ 5-20% by mass.

  As described above, in the present invention, in addition to suppressing dropping and outflow of the glass component, in order to prevent deformation and sagging, and to obtain a fired film having high heat resistance that is stable over the long term, in addition to alumina fine particles, It is preferable to include an oxide material having a relatively large average particle diameter in the coating material. Specifically, for example, it is preferable to add alumina particles or alumina fibers having an average particle diameter in the range of 1 μm to 100 μm as a refractory component. Furthermore, silica particles having an average particle diameter in the range of 1 μm to 100 μm may be added.

  Thus, the reason why the deformation and sagging of the fired coating can be more effectively suppressed by adding an oxide material having a relatively large average particle diameter is not clear, but is an oxide having a relatively large average particle diameter. This is probably because the distribution of the particle diameter of the mullite crystals produced and the arrangement of the mullite crystals in the fired coating matrix are appropriately controlled by the contribution of the material.

  For this reason, the deformation | transformation and sagging of a baked film can be suppressed more effectively by making the average particle diameter of the alumina particle added as a refractory component into 1 micrometer or more. However, if the average particle diameter of the alumina particles exceeds 100 μm, a uniform film may not be formed.

  In addition, the addition of an alumina fiber having an elongated shape as a refractory is very effective in suppressing deformation and sagging of the fired coating. Moreover, it can suppress effectively that a crack etc. arise in the film | membrane which consists of coating materials by adding an alumina fiber.

The average particle diameter D50 of the alumina fiber is preferably 20 μm to 1 mm, more preferably 20 μm to ₅₀₀ μm. If the average particle diameter of the alumina fiber is too small, the increase in the effect of suppressing the glass dropout and outflow tends to be small. On the other hand, if the average particle diameter of the alumina fibers is too large, it may be difficult to uniformly mix the alumina fibers with the coating material, and a uniform fired film may not be obtained.

  A preferable diameter of the alumina fiber is 0.5 μm to 50 μm, and more preferably 0.5 μm to 10 μm. When the diameter of the alumina fiber is too small, the alumina fiber is easily dissolved in the glass component. Therefore, the alumina fiber which exists as a fiber decreases, and the improvement effect of the effect which suppresses dropping and outflow of glass may not be obtained sufficiently. On the other hand, if the diameter of the alumina fiber is too large, a uniform fired film may not be obtained.

  In the present invention, the alumina fiber is not necessarily made of only alumina. The alumina fiber preferably contains 60% by mass or more of alumina, and preferably contains 90% by mass or more of alumina. When the alumina fiber has too little alumina content, the heat resistance of the alumina fiber is lowered, so that the heat resistance of the fired film may be lowered.

In this specification, “alumina fiber” refers to rod-shaped alumina, and specifically means alumina having an average particle diameter D ₅₀ / cross-sectional diameter of 2 or more.

  The content of alumina particles in the coating material is preferably 1% by mass to 20% by mass, more preferably 5% by mass to 20% by mass, and still more preferably 10% by mass to 20% by mass. The content of alumina fibers in the coating material is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and still more preferably 3% by mass to 12% by mass.

  In the present invention, the film thickness of the fired coating for a glass production container is not particularly limited, but can be, for example, about 100 μm to 1500 μm, and preferably in the range of 200 μm to 1500 μm. If the film thickness of the fired coating for a glass production container is too thin, the hydrogen barrier property may be lowered. On the other hand, if the film thickness of the fired coating for a glass production container is too thick, the formation of the film becomes complicated and the time required for forming the film becomes long. Moreover, it exists in the tendency for the baking film for glass manufacturing containers to become easy to damage.

  A glass production container according to the present invention includes the above-described fired film for a glass production container according to the present invention, and a container body made of a noble metal or an alloy containing a noble metal, on which a fired film for a glass production container is formed. Yes.

  As described above, the fired coating for a glass production container according to the present invention has high heat resistance, and can effectively suppress hydrogen permeation over a long period even in a high temperature atmosphere. Therefore, by melting the glass using the glass production container provided with the fired coating for the glass production container according to the present invention, it is effective for a long period of time that bubbles are generated in the molten glass even in a high temperature atmosphere. Can be suppressed.

  In the present invention, the fired coating for the glass production container preferably covers at least a part of the outer surface of the inner surface of the container main body that contacts the glass melt and the outer surface that does not contact the glass melt. . Moreover, it is preferable that the baking film for glass manufacturing containers is formed so that the part located in the outer side of the outer surface of a container main body may be located outside the part which is contacting the glass melt on the inner surface. According to this structure, it can suppress more effectively that a bubble generate | occur | produces in molten glass.

  In the present invention, the fired coating for a glass production container may be formed by laminating a plurality of layers on the surface of the container body, but preferably only one layer is formed. For example, it is conceivable that a film mainly shielding hydrogen and a film that maintains the structure of the film are stacked. However, when a plurality of types of films are formed, it is necessary to consider changes in composition due to reactions at the interface between adjacent films. Therefore, the structure of the fired coating becomes very complicated. On the other hand, the fired coating for a glass production container of the present invention has a function of shielding hydrogen and has high structural stability. Therefore, even when only one layer is formed, Can be effectively shielded. Therefore, when the fired coating for a glass production container of the present invention is formed on the surface of the container body, it is preferable to form only one layer.

  In the present invention, the “glass production container” means a member that has an inner surface that contacts the glass melt and an outer surface that does not contact the glass melt and can hold the glass melt. The “glass production container” includes a container capable of holding a glass melt, a pipe capable of conveying the glass melt, a molding member, and the like. Here, the “forming member” refers to a member used for forming a glass melt into a member having a predetermined shape. Accordingly, the “molding member” includes a molding sleeve, a bowl-shaped molding member used in the overflow down draw method, a nozzle, and the like.

  In the present invention, the container body is not particularly limited as long as it is made of a noble metal or an alloy containing a noble metal. However, since the glass manufacturing container of the present invention is used in a high temperature atmosphere, the container body preferably has a certain degree of rigidity in a high temperature atmosphere. The container body is preferably made of, for example, Pt or an alloy containing Pt. Specific examples of the alloy containing Pt include a Pt / Rh alloy, a Pt / Au alloy, a Pt / Pd alloy, and a Pt / Ir alloy.

  Moreover, in order to improve the rigidity of a container main body, other metals, such as Zr and Ti, may be doped in the container main body, for example. That is, in the present invention, the container body may be doped with other elements in the noble metal or an alloy containing the noble metal.

  The glass manufacturing apparatus which concerns on this invention is equipped with the glass manufacturing container which concerns on the said this invention. Therefore, by using the glass manufacturing apparatus according to the present invention, a glass with few bubbles remaining inside the glass can be manufactured.

  The glass production apparatus of the present invention includes a melting container for melting a glass raw material, a fining container for clarifying molten glass, and a stirring container for stirring the clarified glass melt, A member for forming the glass melt, a first connecting member in which a connecting passage for connecting the melting container and the clarifying container is formed, and a connection for connecting the clarifying container and the stirring container. A melting container, a fining container, and an agitation container, each including a second connection member having a channel formed therein and a third connection member having a connection channel connecting the agitation container and the molding member; At least one of the container, the forming member, and the first to third connecting members may be constituted by the glass manufacturing container of the present invention. Among them, each of the fining container, the stirring container, the molding member, and the second and third connecting members excluding the melting container and the first connecting member is constituted by the glass manufacturing container of the present invention. It is preferable. According to this structure, it can suppress more effectively that a bubble remains in glass.

  The glass manufacturing method according to the present invention uses the glass manufacturing apparatus according to the present invention. Therefore, according to the glass manufacturing method of the present invention, it is possible to manufacture a glass with less bubbles remaining inside the glass.

  In the present invention, the glass to be produced is not particularly limited, but the present invention is suitably applied to the production of a glass substrate for a display in which it is more strongly desired that bubbles do not remain in the glass.

  According to this invention, generation | occurrence | production of the bubble resulting from the water which exists in glass melt can fully be suppressed.

It is a schematic sectional drawing of the container for glass melting of 1st Embodiment. It is a schematic cross-sectional view of a pipe for conveying a glass melt according to a second embodiment. It is a schematic block diagram of the glass melting apparatus of 3rd Embodiment. 4 is a photograph inside a glass melting container in Example 2. FIG. 6 is a photograph inside a glass melting container in Example 5. FIG. 6 is a photograph inside a glass melting container in Example 7. FIG. 10 is a photograph inside a glass melting container in Example 8. FIG. 10 is a photograph inside the glass melting container in Example 9. FIG. In Example 7, it is a photograph of the bottom part of the container for glass melting cooled to room temperature after completion | finish of a foaming test. In Example 8, it is a photograph of the bottom part of the container for glass melting cooled to room temperature after completion | finish of a foaming test. In Example 9, it is a photograph of the bottom part of the container for glass melting cooled to room temperature after completion | finish of a foaming test. In Example 5, it is a photograph in the container for glass melting when the baking days are one day. In Example 5, it is a photograph in the container for glass melting when baking days are three days. In Example 5, it is a photograph in the container for glass melting when the baking days are five days. In Example 5, it is a photograph in the container for glass melting when the baking days are 30 days. It is a graph which shows the measurement result of the X-ray of the coating material before baking in Example 5. 6 is a graph showing the X-ray measurement results of the fired coating after the reboil test in Example 5. 2 is a photograph inside a glass melting container in Comparative Example 1. FIG. 6 is a photograph inside a glass melting container in Comparative Example 3. 10 is a photograph inside the glass melting container in Example 11. FIG. It is the photograph in the container for glass melting in Example 12. FIG.

  Hereinafter, although an example of the preferable form which implemented this invention is demonstrated, this invention is not limited to the following embodiment at all.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a glass melting container according to a first embodiment. In the present embodiment, a glass melting container 10 which is a kind of glass manufacturing container will be described with reference to FIG.

  As shown in FIG. 1, the glass melting container 10 includes a container body 11. The container body 11 is made of a noble metal or an alloy containing a noble metal. Specific examples of the noble metal include Pt, Au, Pd, Rh, Ir, and the like. An example of an alloy containing a noble metal includes an alloy containing Pt. Especially, it is preferable that the container main body 11 is formed with the alloy containing Pt or Pt. This is because Pt or an alloy containing Pt has a relatively high strength at high temperatures. Specific examples of the alloy containing Pt include a Pt / Rh alloy, a Pt / Au alloy, a Pt / Pd alloy, and a Pt / Ir alloy.

  Further, the container body 11 may be doped with other elements such as Zr and Ti for the purpose of improving rigidity and strength. For example, the container body 11 may be made of Pt doped with at least one of Zr and Ti.

  In this embodiment, the container main body 11 is formed in a bowl shape, and the container main body 11 is formed with a recess 11a in which the glass melt 14 is stored. That is, the container body 11 constitutes the surface of the recess 11a, and has an inner surface 11b that contacts the glass melt 14 and an outer surface 11c that does not contact the glass melt 14.

  A fired film 12 is formed on the outer surface 11 c of the container body 11. In the present embodiment, the entire outer surface 11 c of the container body 11 is covered with the fired coating 12. The fired film 12 is a film for suppressing hydrogen in the glass melt from passing through the glass melting container 10 and being released to the outside.

  The fired film 12 is a film obtained by applying a coating material to the outer surface 11c of the container surface 11 and then firing it.

  In the present embodiment, the coating material for forming the fired film 12 is a glass component, alumina fine particles having an average particle diameter in the range of 5 nm to 50 nm, alumina particles having an average particle diameter in the range of 1 μm to 100 μm, Contains alumina fiber and colloidal silica. Moreover, Si component is contained in the glass component. That is, the glass component is a borosilicate glass component or a silicate glass component.

  For this reason, the alumina fine particles contained in the coating material react with the Si component contained in the colloidal silica and the glass component, and mullite having excellent heat resistance is effectively precipitated. Therefore, the fired film 12 of this embodiment is excellent in heat resistance. For this reason, the fired film 12 is less likely to cause the glass component that suppresses the permeation of hydrogen from dropping or flowing out from the fired film for a glass production container even in a high temperature atmosphere. Therefore, by using the glass melting container 10 whose outer surface is covered with the fired coating 12, bubbles are generated in the molten glass due to the hydrogen in the molten glass permeating to the outside of the container. Can be effectively suppressed over a long period of time. As a result, it is possible to continue to produce a glass with few remaining bubbles over a long period of time.

  When the average particle diameter of the alumina fine particles included in the coating material is less than 5 nm, the alumina fine particles are likely to aggregate, and the presence of the fine alumina particles having a small particle diameter is reduced, so that mullite is not efficiently generated. In addition, in the thickness direction of the film, a portion in which the glass component that suppresses the permeation of hydrogen does not exist so much exists in the fired coating 12, and the hydrogen shielding ability may be reduced.

  Even when the average particle diameter of the alumina fine particles exceeds 50 nm, the presence of fine alumina particles having a small particle diameter is reduced, so that mullite is not efficiently generated.

  From the viewpoint of effectively generating mullite, it is preferable to increase the content of alumina fine particles in the coating material. However, when the content of the alumina fine particles in the coating material is excessively increased, the content of the glass component having an effect of shielding hydrogen tends to decrease. Accordingly, the content of the alumina fine particles in the coating material is preferably 0.1% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and 3% by mass to 15% by mass. More preferably.

  From the viewpoint of effectively generating mullite, it is preferable that the coating material contains Si in a molar ratio that is 1/6 or more times that of Al contained in the alumina fine particles.

  The Si component may be composed only of those derived from the glass component, or the Si component may be added separately from the glass component, or added separately from the glass component and the glass component It may be configured by both.

  When the Si component is added to the coating material separately from the glass component, it is preferably added as silica. Specific examples of the silica component to be added include silica particles and colloidal silica. From the viewpoint of effectively generating mullite, it is preferable that the average particle diameter of the silica to be added is small. Therefore, for example, it is preferable to add silica particles having an average particle diameter of 10 μm or less, more preferable to add silica particles having an average particle diameter of 1 μm or less, and more preferable to add colloidal silica.

  In addition, since colloidal silica also functions as an inorganic binder, by adding colloidal silica to the coating material, a dense fired film 12 can be obtained, and the adhesion and adhesion strength of the fired film 12 to the container body 11 can be increased. Can do. Therefore, it is possible to effectively prevent the fired coating 12 from peeling off or dropping off from the container body 11.

  The glass component contained in the coating material is a component that suppresses the permeation of hydrogen. For this reason, from the viewpoint of obtaining a higher hydrogen permeation suppression effect, it is preferable that the content of the glass component in the coating material is higher. However, when the content of the glass component is too large, the content of the refractory component tends to decrease. Therefore, from the viewpoint of improving the heat resistance and durability of the fired coating for a glass production container, it is preferable that the content of the glass component is small.

  Therefore, the content of the glass component in the coating material is usually preferably in the range of 10% by mass to 80% by mass. The content of the glass component in the coating material should be appropriately set according to the characteristics such as the softening temperature of the glass component used, the type and characteristics of the refractory component used, the temperature range used, etc. is there. For example, when the use temperature of the fired coating for a glass production container is in the range of 1000 ° C. to 1250 ° C., the preferable glass component content is usually 35% by mass to 80% by mass. The preferred glass component content when the operating temperature of the fired coating for a glass production container is in the range of 1250 ° C. to 1450 ° C. is usually 20% by mass to 60% by mass. The preferable glass component content is usually 10% by mass to 40% by mass when the use temperature of the fired coating for a glass production container is in the range of 1450 ° C to 1600 ° C.

  Although the kind of glass component is not specifically limited, As mentioned above, it is preferable to use a glass component with a high softening temperature from the viewpoint of effectively suppressing the dropout and outflow of the glass component. Specifically, it is preferable to use a glass component having a softening temperature of 800 ° C. or higher, more preferably a glass component having a softening temperature of 850 ° C. or higher, and more preferably a glass component having a softening temperature of 900 ° C. or higher. Specific examples of the glass component having a high softening temperature include borosilicate glass and silicate glass. Among them, it is more preferable to use borosilicate glass or silicate glass having a low content of alkali components such as Na, K, Li, and alkaline earth components such as Ba, Sr, and Ca as glass components. Furthermore, it is more preferable to use a silicate glass having a small content of an alkaline component such as Na, K, Li, or an alkaline earth component such as Ba, Sr, or Ca as the glass component. It is more preferable to use a so-called alkali-free glass component which does not contain.

For example, the composition range of the preferable glass component when the operating temperature of the fired coating for a glass production container is in the range of 1000 ° C. to 1250 ° C. is SiO ₂ 40 to 70 mass%, Al ₂ O ₃ 1 to 30 mass%. , B ₂ O ₃ 1-30% by mass.

For example, when the use temperature of the fired coating for a glass production container is in the range of 1250 ° C. to 1450 ° C., the preferable composition range of the glass component is SiO ₂ 50 to 75 mass%, Al ₂ O ₃ 5 to 30 mass%. , B ₂ O ₃ 1-20% by mass.

For example, when the use temperature of the fired coating for a glass production container is in the range of 1450 ° C. to 1600 ° C., the preferred composition range of the glass component is 50 to 75% by mass of SiO _{2 and} 10 to 30% by mass of Al ₂ O _3. , B ₂ O ₃ 5-20% by mass.

  Further, in the present embodiment, as described above, in addition to alumina fine particles, in order to prevent the glass component from falling off and flowing out, to prevent deformation and sagging, and to obtain a fired film having a long-term stable high heat resistance. An oxide material having a relatively large average particle diameter is added to the coating material. Specifically, alumina particles or an alumina fiber having an average particle diameter in the range of 1 μm to 100 μm is added. For this reason, deformation and sagging of the fired coating can be more effectively suppressed. As a result, it is possible to effectively suppress the generation of bubbles in the molten glass over a long period of time.

  In addition, the preferable average particle diameter of an alumina fiber is 20 micrometers-1 mm, More preferably, it is 20 micrometers-500 micrometers. If the average particle diameter of the alumina fiber is too small, the increase in the effect of suppressing deformation and sagging of the fired coating tends to be small. On the other hand, if the average particle diameter of the alumina fibers is too large, it may be difficult to uniformly mix the alumina fibers with the coating material, and a uniform fired film may not be obtained.

  A preferable diameter of the alumina fiber is 0.5 μm to 50 μm, and more preferably 0.5 μm to 10 μm. If the diameter of the alumina fiber is too small, the alumina fiber dissolves in the glass component, and the alumina fiber present as the fiber decreases, and the effect of suppressing the deformation and sagging of the fired coating may not be sufficiently obtained. . On the other hand, if the diameter of the alumina fiber is too large, a uniform fired film may not be obtained.

  The alumina fiber does not necessarily need to be made only of alumina. The alumina fiber preferably contains 60% by mass or more of alumina, and preferably contains 90% by mass or more of alumina. When the alumina fiber has too little alumina content, the heat resistance of the alumina fiber is lowered, so that the heat resistance of the fired coating 12 for a glass production container may be lowered.

  Although the film thickness of the baking film 12 for glass manufacturing containers is not specifically limited, For example, it can be set as about 100 micrometers-1500 micrometers, and it is preferable to exist in the range of 200 micrometers-1500 micrometers. If the film thickness of the fired coating 12 for a glass production container is too thin, the hydrogen barrier property may be lowered. On the other hand, when the film thickness of the fired coating 12 for a glass production container is too thick, the film formation becomes complicated and the time required for the film formation becomes long. Moreover, it exists in the tendency for the baked film 12 for glass manufacturing containers to become damaged easily.

  The glass melting container 10 of the present embodiment is suitably used for melting any kind of glass, but among them, glass for display which is more strongly desired that no bubbles remain in the glass. It is particularly preferably used when manufacturing a substrate.

  Although the manufacturing method of the glass melting container 10 of this embodiment is not specifically limited, For example, it can manufacture in the following ways.

  First, the container body 11 is prepared. Next, a layer made of a coating material is formed on the outer surface 11 c of the container body 11. The method for forming the layer made of the coating material is not particularly limited. For example, the layer may be formed by spraying or may be formed by attaching a green sheet formed from a slurry of the coating material.

  Next, the container body 11 on which the layer made of the coating material is formed is heated, the layer made of the coating material is baked, and the fired film 12 is formed.

  In addition, when starting manufacture of glass, it is preferable to perform this baking process simultaneously when heating the container main body 11 prior to manufacture of glass. By doing so, it can suppress that the temperature of the baked film 12 changes a lot. As a result, it is possible to prevent the fired coating 12 from being damaged or falling off.

  Further, in order to prevent the aggregated particles of alumina fine particles from being mixed with the coating material, first, the alumina fine particles are dispersed in the liquid, and further, the liquid from which the aggregated particles have been removed by filtration using a sieve is removed from the coating material. It is preferably used for preparation. The opening of the sieve to be used is preferably in the range of 100 μm to 500 μm, and more preferably in the range of 200 μm to 350 μm. If the sieve opening used is too small, the liquid in which the alumina fine particles are dispersed tends to be difficult to pass through the sieve. On the other hand, if the sieve opening used is too large, the aggregated particles may not be sufficiently removed.

(Second Embodiment)
In the said 1st Embodiment, the container 10 for glass melting was mentioned as an example and demonstrated as an example of the glass manufacturing container which implemented this invention. However, in the present invention, the glass production container is not limited to the glass melting container 10. The glass manufacturing container may be, for example, a pipe for transporting glass melt. In the present embodiment, a glass melt conveying pipe which is a kind of glass manufacturing container will be described with reference to FIG.

  In the description of the present embodiment, members having substantially the same functions as those in the first embodiment are referred to by the same reference numerals, and description thereof is omitted.

  FIG. 2 is a schematic cross-sectional view of the glass melt conveying pipe of the second embodiment. As shown in FIG. 2, in the glass melt conveyance pipe 20 of the present embodiment, the container body 11 is formed in a cylindrical shape. The outer surface 11 c of the container body 11 is covered with the fired coating 12.

Also in this embodiment, since the outer surface 11c of the container main body 11 is covered with the fired coating 12 as in the first embodiment, oxygen gas caused by water or OH ⁻ ions in the glass melt is used. Generation | occurrence | production can be suppressed effectively.

(Third embodiment)
In this embodiment, a glass manufacturing apparatus using the glass melting container 10 and the glass melt conveying pipe 20 described in the first and second embodiments will be described with reference to FIG. In addition, the glass manufacturing apparatus of this embodiment is an apparatus for shape | molding the glass substrate for a display by the overflow downdraw method.

  As shown in FIG. 3, the glass manufacturing apparatus 1 includes a melting container 31, a fining container 32, a stirring container 33, a pot 34, a molding member 35, and a heating element (not shown). . The melting container 31 is a container for melting the charged glass raw material (batch). The melting container 31 is connected to the fining container 32 by a first connection passage 36 a formed inside the first connection member 36. The clarification container 32 is a container for clarifying the glass melt shared from the melting container 31. The clarification container 32 is connected to the agitation container 33 by a second connection passage 37 a formed inside the second connection member 37. The stirring container 33 is a container for stirring and homogenizing the clarified glass melt. The stirring container 33 is connected to the molding member 35 by a third connection passage 38 a formed in the third connection member 38, a pot 34, and a pipe 39.

  In the present embodiment, at least one of the containers 31 to 33, the pot 34, the connecting members 36 to 38, the pipe 39 and the molding member 35 is constituted by the glass melting container 10 or the glass melt conveying pipe 20. ing. Specifically, the melting container 31 and the molding member 35 are constituted by a refractory furnace made of a refractory, and a clarification container 32, a stirring container 33, a pot 34, connection members 36 to 38, and pipes 39 are provided. Each is comprised by the said glass melting container 10 or the pipe 20 for glass melt conveyance. For this reason, according to the glass manufacturing apparatus 1 of this embodiment, the glass by which it was suppressed that a bubble remained in glass can be manufactured.

  The melting container 31 may also be constituted by the glass melting container 10 described above, but it is not always necessary to apply the glass manufacturing container in which the present invention is applied to a container upstream from the fining container 32.

  Hereinafter, the present invention will be described in more detail. However, the present invention is not limited to the following examples, and can be appropriately modified and implemented without departing from the scope of the present invention.

Example 1
The glass melting container 10 shown in the first embodiment was produced under the following conditions, and a foaming test was performed under the following conditions.

  Container body 11: crucible made of Pt / Rh alloy (Rh content: 10% by mass) having a diameter of 46 mm and a height of 40 mm, the surface of which is blasted

Composition of coating material: Glass powder: 50% by mass, alumina fiber (Denka Alsen BULK (Al ₂ O ₃ / SiO ₂ = 97/3) pulverized in an alumina mortar, average particle size: about 27 μm): 10 Mass%, alumina fine particles (average particle diameter: about 13 nm): 1 mass%, alumina particles (average particle diameter: about 50 μm): 14 mass%, colloidal silica (Grace Ludox): 25 mass%, glass powder: Japan OA-10 manufactured by Electric Glass Co., Ltd.

  Film thickness of fired coating 12: 850 μm

  Preparation of fired coating 12 and foaming experiment: A coating material slurry was applied little by little by a spray method while the glass melting container 10 was heated to about 80 ° C. to 95 ° C. with a hot air gun. Then, it was dried at 80 ° C. for about 1 day. The glass melting container 10 with a coating film was heated to a temperature at the time of glass melting (1300 ° C.) at a temperature rising rate of 10 ° C./min, and baked at that temperature for 3 days. Next, glass (OA-10, manufactured by Nippon Electric Glass Co., Ltd.) is put into the glass melting container 10 with the fired coating, and further maintained at that temperature for 2 hours. Thereafter, the glass melting container 10 The state of the foam inside was confirmed visually. The results are shown in Table 1 below.

  In Table 1, “◎ (double circle)” indicates a case where no platinum interfacial foaming is observed and the bubble area ratio is less than about 3%. “◯ (circle)” indicates a case where platinum interfacial foaming is hardly observed and the bubble area ratio is approximately 3% or more and less than 10%. “X (Batsu)” indicates a case where platinum interfacial foaming is observed and the bubble area ratio is approximately 10% or more.

(Examples 2-9)
A foaming test was conducted in the same manner as in Example 1 except that a coating material having the composition shown in Table 1 below and an average particle diameter of alumina fiber was used. The results are shown in Table 1 below. Moreover, the photograph in the container 10 for glass melting in Example 2, 5, 7-9 is shown in FIGS. 9 to 11 show photographs of the bottom (coating film) of the glass melting container 10 cooled to room temperature after completion of the foaming test in Examples 7-9.

  Moreover, in Example 5, the reboil test was performed by changing the baking days of a coating material at 1300 degreeC. 12 to 15 show photographs in the glass melting container 10 when the firing days are 1, 3, 5, and 30 days, respectively.

  FIG. 16 shows the X-ray measurement results of the coating material before firing in Example 5. In FIG. 16, triangles (Δ) are peaks derived from alumina, and x is a peak derived from silica. In FIG. 17, the measurement result of the X-ray of the baked film 12 after the reboiling test in Example 5 is shown. In FIG. 17, a circle (◯) is a peak derived from mullite.

  From the comparison between FIG. 16 and FIG. 17, it can be seen that the mullite is not included in the coating material before firing, and that mullite is generated by firing.

(Comparative Example 1)
As shown in Table 2 below, a foaming test was conducted in the same manner as in Example 1 except that no fired film was provided. The results are shown in Table 2 below. FIG. 18 shows a photograph inside the glass melting container 10 in Comparative Example 1.

(Comparative Example 2)
A foaming test was conducted in the same manner as in Example 1 except that a coating material having the composition shown in Table 2 below and an average particle diameter of alumina fiber was used. The results are shown in Table 2 below. FIG. 19 shows a photograph of the glass melting container 10 in Comparative Example 2.

  As shown in Tables 1 to 2 and FIGS. 4 to 15, 18 and 19, in Comparative Example 1 in which no fired coating was provided and in Comparative Example 2 in which no alumina fine particles were added to the coating material, Bubbles were confirmed. On the other hand, in Examples 1 to 9 in which alumina fine particles were added to the coating material and a fired film was provided, good results were obtained in the foaming test. From this result, it can be seen that the generation of bubbles can be effectively suppressed by firing a coating material to which alumina fine particles are added and providing a fired film containing mullite. This is because, as described above, the baked film for glass production containers containing mullite crystals is excellent in heat resistance, and also suppresses the permeation of hydrogen from the baked film for glass production containers even in a high temperature atmosphere. This is because it is possible to effectively suppress omission and outflow.

(Examples 10 to 12)
A glass melting container 10 was produced in the same manner as in Example 1 except that the coating material having the composition shown in Table 1 below was used. Further, a foaming test was conducted in the same manner as in Example 1 except that the glass melting temperature was 1550 ° C. The results are shown in Table 3 below. 20 and 21 show photographs inside the glass melting container 10 in Examples 11 and 12.

(Comparative Example 3)
A glass melting container 10 was prepared and subjected to a foaming test in the same manner as in Example 10 except that the coating material having the composition shown in Table 3 below was used. The results are shown in Table 3 below.

  As shown in Table 3 and FIGS. 20 and 21, when the glass melting temperature was 1550 ° C., as in the case where the glass melting temperature was 1300 ° C., a comparison in which alumina fine particles were not added to the coating material In Example 3, many foams were confirmed in the foam test. On the other hand, in Examples 10 to 12 in which alumina fine particles were added to the coating material and a fired film was provided, good results were obtained in the foaming test. From this result, it can be seen that, regardless of the glass melting temperature, it is obtained by firing the coating material to which alumina fine particles are added, and by providing a fired film containing mullite, the generation of bubbles can be effectively suppressed.

DESCRIPTION OF SYMBOLS 1 ... Glass manufacturing apparatus 10 ... Glass melting container 11 ... Container main body 11a ... Concave 11b ... Inner surface 11c of container main body ... Outer surface 12 of container main body ... Firing coating 14 ... Glass melt 20 ... Pipe 31 for glass melt conveyance ... melting container 32 ... clarification container 33 ... stirring container 34 ... pot 35 ... molding member 36 ... first connection member 36a ... first connection passage 37 ... second connection member 37a ... second connection passage 38 ... third connection member 38a ... third connection passage 39 ... pipe

Claims (17)

A glass manufacturing container coating material for forming the fired film of a glass manufacturing container comprising a container body made of a noble metal or an alloy containing a noble metal, and a fired film formed on the surface of the container body,
A glass component;
Alumina fine particles having an average particle diameter in the range of 5 nm to 50 nm,
Coating material for glass production container containing Si component.   The coating material for a glass manufacturing container according to claim 1, further comprising silica as the Si component.   The glass manufacturing container coating material according to claim 1, wherein the glass component contains at least a part of the Si component.   The coating material for glass manufacturing containers as described in any one of Claims 1-3 which further contains the alumina particle which has an average particle diameter in the range of 1 micrometer-100 micrometers.   The coating material for glass manufacturing containers as described in any one of Claims 1-4 which further contains an alumina fiber.   The coating material for glass production containers according to any one of claims 2 to 5, wherein the silica is colloidal silica.   The baked film for glass manufacturing containers formed by baking the coating material for glass manufacturing containers as described in any one of Claims 1-6.   The fired film for a glass production container according to claim 7, comprising mullite crystals.   A glass production container comprising: the fired coating for a glass production container according to claim 7 or 8; and a container main body made of a noble metal or an alloy containing the noble metal, the fired coating for the glass production container being formed on a surface thereof. The container body has an inner surface that contacts the glass melt and an outer surface that does not contact the glass melt,
The glass manufacturing container according to claim 9, wherein the fired coating for the glass manufacturing container covers at least a part of the outer surface of the container main body.   The glass container according to claim 9 or 10, wherein the container body is made of Pt or an alloy containing Pt.   The glass production container according to any one of claims 9 to 11, wherein one layer of the fired coating for the glass production container is formed on the surface of the container main body.   A glass manufacturing apparatus provided with the glass manufacturing container as described in any one of Claims 9-12. A melting container for melting glass raw materials;
A fining container for fining the molten glass;
A stirring vessel for stirring the clarified glass melt;
A molding member for molding the glass melt;
A first connection member in which a connection passage connecting the melting container and the clarification container is formed;
A second connection member in which a connection passage connecting the clarification container and the stirring container is formed;
A third connection member formed with a connection passage for connecting the stirring vessel and the molding member;
14. The melting container, the clarification container, the stirring container, the molding member, and at least one of the first to third connection members are configured by the glass manufacturing container. Glass manufacturing equipment.   The glass manufacturing apparatus according to claim 14, wherein each of the fining container, the stirring container, the molding member, and the second and third connection members is configured by the glass manufacturing container.   The manufacturing method of the glass using the glass manufacturing apparatus as described in any one of Claims 13-15.   The method for producing glass according to claim 16, wherein the glass is a glass substrate for display.