JP5704500B2 - Manufacturing method of glass plate - Google Patents

Description

  The present invention relates to a method for producing a glass plate, and more particularly to a method for producing a glass plate for a plasma display panel (PDP) or a glass plate for a solar cell panel.

  In recent years, the demand for solar cells has increased from an environmental viewpoint. In particular, single crystal silicon, polycrystalline silicon, amorphous silicon solar cells, and the like are mainly used for household power generation, commercial power generation, and the like. Solar cells such as chalcopyrite thin film polycrystalline solar cells, CdTe solar cells, dye-sensitized solar cells, and organic thin film solar cells are also being put into practical use.

  Generally, a solar cell has a structure in which an electrode film, a light absorption layer, and an electrode film are provided on the surface of a glass plate, and a protective glass plate is provided thereon. The glass plate for a solar cell is required to have heat resistance because an electrode film and a light absorption layer are formed by a heat treatment process. For this reason, high strain point glass is currently used for this application.

International Publication No. 08/098968 Pamphlet

  In recent years, recycling of resources has been promoted from an environmental viewpoint, and glass products are no exception. However, looking at the glass products as a whole, the recycling rate is not high and it is difficult to say that they meet environmental requirements. Further, in the process of manufacturing a glass product, a considerable amount of waste glass is generated. However, from an environmental viewpoint, it is highly necessary to recycle the waste glass and reduce it to a glass product. In particular, alkali-free glass used for liquid crystal displays has a high need for promoting recycling because of its large circulation and production.

  Further, the conventional high strain point glass is inferior in productivity because of the low solubility of the glass batch as compared with a general-purpose soda lime glass, and as a result, the manufacturing cost is increased.

  Therefore, the present invention promotes the recycling of alkali-free glass, and invented a method for producing a glass plate excellent in glass batch solubility, while increasing the recycling rate of alkali-free glass, A technical issue is to reduce the manufacturing cost.

The present gun inventors have intensive studies results, the waste glass alkali-free glass using a portion of the glass raw material, by making the glass plate of high strain point, can solve the above technical problems, It is proposed as the present invention. That is, the method for producing a glass plate of the present invention comprises preparing a glass raw material, preparing a glass batch, then melting the glass batch in a glass melting furnace, and forming the glass plate into a glass plate. In addition, alkali-free glass is used for a part of the glass, and the glass plate has a glass composition of mass% in terms of the following oxides: SiO ₂ 40 to 75%, Al ₂ O ₃ 1 to 18%, B ₂ O ₃ 0. 1-12%, RO (MgO + CaO + SrO + BaO, that is, MgO, CaO, SrO, BaO total amount) 5-30%, MgO 0-10%, CaO 0-20%, SrO 0-15%, BaO 0-15%, The glass raw material is prepared so as to contain Na ₂ O + K ₂ O (total amount of Na ₂ O, K ₂ O) 1 to 25% and K ₂ O 1 to 15% .

  The method for producing a glass plate of the present invention is characterized in that alkali-free glass is used as a part of the glass raw material. When alkali-free glass is used as a part of the glass raw material, the content ratio of alkali metal oxides and the like in other glass raw materials (carbonate, nitrate, sulfate, etc.) increases. When the content ratio of the alkali metal oxide or the like in the glass raw material other than the alkali-free glass is increased, the solubility of the glass batch is improved, so that the productivity of the glass plate having a high strain point can be dramatically increased. Further, since the alkali-free glass is once vitrified, the solubility of the glass batch is not significantly reduced. In addition, the manufacturing method of the glass plate of this invention does not exclude the aspect which uses waste glass other than an alkali free glass for a part of glass raw material.

  Furthermore, when alkali-free glass is used as a part of the glass raw material, recycling of alkali-free glass can be promoted, so that recent environmental demands can be satisfied.

The method for producing a glass plate of the present invention is characterized in that the glass raw material is prepared so that the glass plate has the above glass composition. If it does in this way, the strain point and thermal expansion coefficient of a glass plate are in an appropriate range (for example, strain point: 560 ° C. or more and less than 625 ° C., thermal expansion coefficient at 30 to 380 ° C .: 60 to 90 × 10 ⁻⁷ / ° C. ), And as a result, it can be easily applied to PDPs and solar cells. In particular, the method for producing a glass plate of the present invention is characterized in that the glass material is prepared so that the glass plate contains 0.1% by mass or more of B ₂ O ₃ in the glass composition. In this way, the melting temperature and the molding temperature are lowered, that is, the meltability and the moldability are improved, so that the productivity of the glass plate is improved, and as a result, the manufacturing cost of the glass plate can be reduced. it can.

In the method for producing a glass plate of the present invention, it is preferable to prepare the glass raw material so that the content of the alkali-free glass in the glass batch is 1 to 90% by mass.

As for the manufacturing method of the glass plate of this invention, it is preferable that an alkali free glass grind | pulverizes the plate-shaped object of plate thickness 0.7mm or less.

Process for producing a glass plate of the present invention, a glass plate, as a glass composition, in weight percent terms of _{oxide, As 2 O 3 + Sb 2} O 3 + SnO 2 + SO 3 (As 2 O 3, Sb 2 O 3, The glass raw material is prepared so as to contain 0.02 to 5% of the total amount of SnO ₂ and SO ₃ .

In the method for producing a glass plate of the present invention, it is preferable to prepare the glass raw material so that the temperature at 10 ^4.0 dPa · s is less than 1200 ° C. Here, “temperature at 10 ⁴ dPa · s” refers to a value measured by a platinum ball pulling method. Note that the temperature at 10 ⁴ dPa · s is a temperature that serves as a guide when forming a glass plate, that is, a temperature corresponding to the forming temperature, and the lower the temperature, the easier the glass plate is formed.

In the method for producing a glass plate of the present invention, it is preferable to prepare the glass raw material so that the strain point is 560 ° C. or higher. Here, the “strain point” refers to a value measured based on ASTM C336-71.

Process for producing a glass plate of the present invention, an alkali-free glass, as a glass composition, in weight percent terms of _{oxide, SiO 2 55~75%, Al 2} O 3 2~20%, B 2 O 3 1~ 12%, 0~10% MgO, CaO 0~10%, SrO 0~10%, BaO 0~15%, 0~1% ZnO, As 2 O 3 0~1%, Sb 2 O 3 0~1% , _SnO 2 _0~1%, preferably contains SO 3 0 to 0.5%.

As for the manufacturing method of the glass plate of this invention, it is preferable to shape | mold a glass plate by the float glass process.

In the method for producing a glass plate of the present invention, the glass plate is preferably a plasma display glass plate or a solar cell glass plate. The solar cell glass plate includes both a substrate and a cover glass.

It is preferable that the glass plate of this invention is produced by said method.

In the manufacturing method of a glass plate for a solar cell of the present invention, a glass plate, as a glass composition, in weight percent terms of _{oxide, SiO 2 40~75%, Al 2} O 3 1~18%, B 2 O 3 0.1~12%, RO 5~30%, 0~10 % MgO, CaO 0~20%, SrO 0~15%, BaO 0~15%, Na 2 O + K 2 O 1 ~25%, K 2 O A glass raw material is prepared so as to contain 1 to 15% . The reason for limiting the glass composition range of the glass plate as described above in the method for producing a glass plate of the present invention will be described below. In addition, the following% display points out the mass% unless there is particular notice.

SiO ₂ is a component that forms a glass network and a component that increases the strain point, and its content is 40 to 75%, preferably 43 to 60%, more preferably less than 45 to 55%. When the content of SiO ₂ decreases, the high-temperature viscosity becomes too low, the liquid phase viscosity tends to decrease, and it becomes difficult to promote recycling of the alkali-free glass. On the other hand, when the content of SiO ₂ increases, the high-temperature viscosity becomes too high, and the meltability and moldability tend to decrease.

B ₂ O ₃ is a component that acts as a flux and lowers the high temperature viscosity to improve the meltability and moldability, and its content is 0.1 to 12%, preferably 1 to 8%. When the content of B ₂ O ₃ is reduced, meltability and formability are lowered, the productivity of the glass plate is easily lowered, and it is difficult to promote recycling of the alkali-free glass. On the other hand, when the content of B ₂ O ₃ increases, the high temperature viscosity becomes too low, the liquid phase viscosity tends to decrease, and the strain point tends to decrease.

Al ₂ O ₃ is a component that increases the strain point, and its content is 1 to 18%, preferably 4 to 15%, and more preferably 5 to 13%. When the content of Al ₂ O ₃ decreases, the strain point tends to decrease and it becomes difficult to promote recycling of the alkali-free glass. On the other hand, when the content of Al ₂ O ₃ increases, the high-temperature viscosity becomes too high, and the meltability and moldability tend to decrease.

RO is a component that lowers the temperature at 10 ^4.0 dPa · s and the melting temperature, and its content is 5 to 30%, preferably 10 to 25%, more preferably 15 to 25%. When the content of RO is less, there is a tendency that the strain point is lowered, there is a tendency that the temperature and the melting temperature of the high temperature viscosity 10 ^{4.0 dPa} · s is increased. On the other hand, when the content of RO increases, the glass tends to devitrify, and it becomes difficult to form the glass plate.

  MgO is a component that lowers the high-temperature viscosity and improves meltability and moldability, and its content is 0 to 10%, preferably 1 to 8%. When the content of MgO increases, the strain point tends to increase, but the high-temperature viscosity becomes too low, and the glass tends to devitrify, so the liquidus temperature rises and the liquidus viscosity tends to decrease. .

  CaO is a component that increases the meltability and moldability by reducing the high-temperature viscosity, and its content is 0 to 20%, preferably 2 to 10%. When the content of CaO decreases, it becomes difficult to promote recycling of the alkali-free glass. On the other hand, as the CaO content increases, the strain point tends to increase, but the high-temperature viscosity becomes too low, and the glass tends to devitrify, so the liquidus temperature rises and the liquidus viscosity decreases. It becomes easy.

  SrO is a component that lowers the high-temperature viscosity and improves meltability and moldability, and its content is 0 to 15%, preferably 2 to 12%. When the SrO content increases, the strain point tends to increase, but the high-temperature viscosity becomes too low, and the glass tends to devitrify, so the liquidus temperature rises and the liquidus viscosity tends to decrease. .

  BaO is a component that increases the meltability and moldability by reducing the high-temperature viscosity, and its content is 0 to 15%, preferably 1 to 12%, more preferably 4 to 10%. When the content of BaO increases, the strain point tends to increase, but the high-temperature viscosity becomes too low, and the glass tends to devitrify, so the liquidus temperature rises and the liquidus viscosity tends to decrease. .

Na ₂ O + K ₂ O is a component that significantly lowers the high-temperature viscosity and improves meltability and moldability, and its content is preferably 1 to 25%, 1 to 20%, and particularly preferably 2 to 15%. When the content of Na ₂ O + K ₂ O increases, the high temperature viscosity becomes too low, the liquid phase viscosity tends to decrease, and the strain point tends to decrease.

Na ₂ O is a component that significantly lowers the high-temperature viscosity and improves meltability and moldability, and its content is preferably 0 to 20%, 0.5 to 10%, and particularly preferably 2 to 8%. When the content of Na ₂ O increases, the high temperature viscosity becomes too low, the liquid phase viscosity tends to decrease, and the strain point tends to decrease.

K ₂ O is a component that significantly lowers the high-temperature viscosity and improves the meltability and moldability, and the content is preferably 1 to 15%, 1 to 13%, and particularly preferably 2 to 12%. When the content of K ₂ O increases, in addition to the high temperature viscosity and the liquid phase viscosity being easily lowered, the strain point is liable to be lowered.

  In addition to the above components, the following components may be added.

ZrO ₂ is a component that increases the strain point, and its content is preferably 0 to 10%, particularly preferably 1 to 8%. When the content of ZrO ₂ increases, the high-temperature viscosity becomes too high, and the meltability and moldability tend to decrease.

As ₂ O ₃ + Sb ₂ O ₃ + SnO ₂ + SO ₃ is a component that acts as a refining agent, and is a component that homogenizes the molten glass by outgassing. The content of As ₂ O ₃ + Sb ₂ O ₃ + SnO ₂ + SO ₃ is preferably 0 to 5%, 0.02 to 5%, particularly preferably 0.1 to 1%. When the content of As ₂ O ₃ + Sb ₂ O ₃ + SnO ₂ + SO ₃ decreases, the clarification effect becomes poor, and defoaming becomes difficult and homogenization of the molten glass becomes difficult. On the other hand, when the content of As ₂ O ₃ + Sb ₂ O ₃ + SnO ₂ + SO ₃ increases, gas is generated too much and a bubble layer is formed on the surface of the molten glass being melted. As a result, the molten glass is heated uniformly. It becomes difficult to make it difficult, or bubbles caused by the foam layer easily flow out to the glass plate. As ₂ O ₃ is a component that acts as a fining agent, but it is desirable that it is not substantially contained from an environmental viewpoint. Here, “substantially does not contain As ₂ O ₃ ” refers to the case where the content of As ₂ O ₃ in the glass composition is 1000 ppm or less. Further, it may be desirable to Sb ₂ O ₃ is also substantially free from an environmental point of view. Here, “substantially does not contain Sb ₂ O ₃ ” refers to a case where the content of Sb ₂ O ₃ in the glass composition is 1000 ppm or less.

The content of TiO ₂ is preferably 0 to 7%, particularly preferably 0 to 5%. When the content of TiO ₂ increases, the high-temperature viscosity becomes too high, and the meltability and moldability tend to decrease. In the case of using the solar cell cover glass, the content of TiO ₂ is preferably 0.1% or more. In this way, ultraviolet coloring can be prevented.

In addition to the above components, other components (for example, Fe ₂ O ₃ , TiO ₂ , CeO ₂ , NiO, CoO, etc.) can be added up to 10%.

  In the manufacturing method of the glass plate of this invention, content of the alkali free glass in a glass batch is 1-90 mass%, 10-85 mass%, Especially 30-75 mass% is preferable. When the content of the alkali-free glass is reduced, it becomes difficult to increase the solubility of the glass batch and it is difficult to promote the recycling of the alkali-free glass. On the other hand, when the content of alkali-free glass is increased, the adjustment range of the glass composition of the glass plate is reduced, and it is difficult to introduce carbonates, nitrates, sulfates, fining agents, and the like that generate gas during melting into the glass raw material. Therefore, due to this, the homogeneity of the molten glass is reduced, and problems such as difficulty in defoaming easily occur. In addition, a non-uniform | heterogenous glass plate tends to enter into a glass plate by heat processing, and this may cause a crack etc. Further, when the bubbles are exposed on the glass plate surface, it is difficult to form the electrode film uniformly.

  In the method for producing a glass plate of the present invention, the alkali-free glass is preferably obtained by pulverizing a plate-like body having a thickness of 0.7 mm or less. If a plate-like body having a plate thickness of 0.7 mm or less is pulverized, the particle size of the alkali-free glass is reduced, and the homogeneity of the molten glass and the solubility of the glass batch are easily improved.

  In the manufacturing method of the glass plate of this invention, it is preferable to grind alkali-free glass so that a particle size may be 10 mm or less, especially 5 mm or less. When the particle size of the alkali-free glass is increased, the homogeneity of the molten glass and the solubility of the glass batch are likely to be lowered. Here, “a particle size of 10 mm or less” refers to a particle size that passes through a sieve having an opening of 10 mm.

The method of manufacturing a glass plate of the present ^{invention, 10} 4.0 dPa · Temperature in s is less than 1200 ° C., 1170 ° C. or less, in particular to be less than 1150 ° C., it is preferable to formulate a glass raw material. If it does in this way, it will become easy to shape | mold a glass plate by the float method, the overflow downdraw method, the roll-out method. When the temperature at 10 ^4.0 dPa · s is higher than 1200 ° C., the molten glass is easily deteriorated due to component volatilization at the time of molding, and the molding temperature becomes high, resulting in an increased load on the molding apparatus. The life of the molding apparatus is shortened and the manufacturing cost of the glass plate is likely to increase. On the other hand, if the temperature at 10 ^4.0 dPa · s is too low, the strain point tends to decrease, and therefore the temperature at 10 ^4.0 dPa · s is preferably 1050 ° C. or higher.

  In the manufacturing method of the glass plate of this invention, it is preferable to prepare a glass raw material so that a strain point may be 560 degreeC or more, 570 degreeC or more, 575 degreeC or more, especially 580 degreeC or more and less than 625 degreeC. When the strain point is lower than 560 ° C., the glass plate tends to be thermally deformed in a high-temperature heat treatment process.

In the manufacturing method of the glass plate of this invention, it is preferable to prepare a glass raw material so that a thermal expansion coefficient may be 75-95 * 10 < ^-7 > / degreeC, especially 80-90 * 10 < ^-7 > / degreeC. This makes it easy to match the thermal expansion coefficient of the frit, dielectric material, partition wall material, light absorption layer such as CIS, and oxide semiconductor porous film such as titanium oxide. As a result, it becomes easy to prevent peeling and cracking of these materials. Here, “thermal expansion coefficient” refers to an average value of linear thermal expansion coefficient in a temperature range of 30 to 380 ° C. with a dilatometer using a cylinder having a diameter of 5.0 mm and a length of 20 mm as a measurement sample.

In the method for producing a glass plate of the present invention, the liquid phase viscosity is 10 ^4.0 dPa · s or more, 10 ^4.4 dPa · s or more, 10 ^4.8 dPa · s or more, particularly 10 ^5.0 dPa · s or more. It is preferable to prepare the glass raw material so that When the liquid phase viscosity is lower than 10 ^4.0 dPa · s, crystals are likely to precipitate on the glass during molding, and the productivity of the glass plate is lowered. Here, “liquid phase viscosity” refers to a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method. “Liquid phase temperature” refers to a glass powder that passes through a standard mesh of 30 mesh (a sieve opening of 500 μm) and remains in a mesh of 50 mesh (a sieve opening of 300 μm) in a platinum boat for 24 hours in a temperature gradient furnace. After holding, it refers to the lowest temperature at which crystals precipitate (initial phase precipitation temperature).

In the method for producing a glass plate of the present invention, the alkali-free glass is, as a glass composition, mass% in terms of the following oxide, SiO ₂ 55 to 75%, Al ₂ O ₃ 2 to 20%, B ₂ O ₃ 1 to 1. 12%, 0~10% MgO, CaO 0~10%, SrO 0~10%, BaO 0~15%, 0~1% ZnO, As 2 O 3 0~1%, Sb 2 O 3 0~1% , _SnO 2 _0~1%, preferably contains SO 3 0 to 0.5%. The alkali-free glass having the above glass composition has a high necessity for recycling because of a large amount of circulation and production. Further, alkali-free glass, a glass composition, it is preferably not substantially free of _{As 2 O 3, Sb 2 O} 3. In this way, the content of As ₂ O ₃ and Sb ₂ O _{3 in} the glass plate can be reduced, and thus recent environmental requirements can be satisfied.

  In the method for producing a glass plate for a solar cell of the present invention, the glass plate can be formed by a float method, a slot down draw method, an overflow down draw method, a redraw method, a roll out method or the like. In particular, the float process is preferable because a large glass plate can be formed at low cost.

  In the manufacturing method of the glass plate of this invention of this invention, it is preferable to shape | mold a glass plate so that plate | board thickness may be 4 mm or less, 3 mm or less, especially less than 2 mm. As the plate thickness of the glass plate is smaller, the PDP and the solar cell can be made thinner and lighter.

  In the method for producing a glass plate of the present invention, it is preferable that a glass batch is melted in a glass melting furnace and formed into a glass plate for PDP. The PDP is manufactured by making the front glass plate and the rear glass plate face each other, aligning the electrodes and the like, and then frit-sealing the periphery at about 500 to 600 ° C. A transparent electrode made of an ITO film, a nesa film or the like is formed on the surface of the front glass plate, and a dielectric layer is formed on the transparent electrode. An electrode made of Al, Ag, Ni or the like is formed on the surface of the rear glass plate, and a dielectric layer and a partition are formed on the electrode. The dielectric layer and the partition walls are formed by a heat treatment process of about 500 to 600 ° C., respectively. Conventionally, soda lime glass molded to a plate thickness of 1.5 to 3.0 mm by a float method or the like has been used as a glass plate for PDP. However, since soda lime glass has a low strain point, it has a problem that it is likely to undergo thermal deformation and thermal shrinkage by the heat treatment process of PDP. For this reason, at present, high strain point glass plates are widely used in order to suppress thermal deformation and thermal shrinkage due to heat treatment. Considering the above points, the method for producing a glass plate of the present invention is suitable as a method for producing a glass plate for this application because the production cost of a glass plate having a high strain point can be reduced.

In the method for producing a glass plate of the present invention, it is preferable that a glass batch is melted in a glass melting furnace and formed into a glass plate for a chalcopyrite thin film polycrystalline solar cell. Chalcopyrite thin film polycrystalline solar cell, on a glass plate, Cu as the light absorbing layer, an In, Ga, chalcopyrite-type compound consisting of Se such as semiconductor, Cu (IN, Ga) Se ₂ or the like is formed. The chalcopyrite type compound semiconductor is produced by a selenization method or the like, and the heat treatment temperature at that time is about 500 to 600 ° C. In addition, the higher the strain point of the glass plate, the harder the glass plate is deformed even when heat-treated at a high temperature, so that a light absorption layer can be stably formed on the glass plate. The characteristics of the crystalline solar cell can be enhanced. Considering the above points, the method for producing a glass plate of the present invention is suitable as a method for producing a glass plate for this application because the production cost of a glass plate having a high strain point can be reduced.

  In the method for producing a glass plate of the present invention, it is preferable that a glass batch is melted in a glass melting furnace and formed into a glass plate for a dye-sensitized solar cell. In a dye-sensitized solar cell, first, a transparent conductive film (for example, ITO, FTO, ATO) is formed on a glass plate by a sputtering method, and then oxide semiconductor fine particles are applied on the glass plate and heat-treated. Then, an oxide semiconductor porous film is formed. Here, the heat treatment temperature for forming the oxide semiconductor porous film may exceed 600 ° C. in some cases. Next, after the dye is adsorbed on the oxide semiconductor porous film, a cell is prepared using a glass plate on which the oxide semiconductor porous film is formed and a glass plate on which a transparent conductive film is formed, and iodine redox or the like The inside of the cell is filled with an electrolyte solution containing a redox couple. In addition, the higher the strain point of the glass plate, the more difficult the glass plate is deformed even at a high heat treatment temperature, and the oxide semiconductor porous film can be stably formed on the glass plate. The characteristics of the sensitized solar cell can be enhanced. Considering the above points, the method for producing a glass plate of the present invention is suitable as a method for producing a glass plate for this application because the production cost of a glass plate having a high strain point can be reduced.

  In the manufacturing method of the glass plate of this invention, in order to raise the mechanical strength of a glass plate, after shaping | molding a glass plate, the surface of a glass plate can also be strengthened (physical strengthening process or chemical strengthening process).

  The present invention will be described in detail based on examples. The present invention is not limited to these examples.

Table 1 shows the glass composition of waste glass. Table 2, specimen No. 1-7 are shown.

  Each sample shown in Table 2 was prepared as follows. First, waste glass (plate-like body having a plate thickness of 0.7 mm) of Samples A and B shown in Table 1 was pulverized to a particle size of 5 mm or less to obtain a glass raw material. Moreover, the waste glass of the samples C and D described in Table 1 was pulverized to a particle size of 5 mm or less to obtain a glass raw material. Further, various oxides were used as glass raw materials. Next, various glass raw materials were prepared so as to have the glass composition shown in Table 2, and glass batches were produced. In addition, various waste glass was added in the ratio as described in the table. Subsequently, the obtained glass batch was melted in a continuous melting furnace, and then formed into a 1.8 mm thick glass plate by a float process. Finally, the obtained glass plate was cut into a size of 200 mm × 200 mm to obtain each sample.

For each sample obtained, the strain ^point, the temperature at ¹⁰ 4.0 dPa · s, the liquid phase temperature was evaluated liquidus viscosity, homogeneity.

  The strain point is a value measured by the method described in ASTM C336-71.

The temperature at 10 ^4.0 dPa · s is a value measured by a platinum ball pulling method.

  The liquid phase temperature passes through a standard sieve 30 mesh (a sieve opening of 500 μm), the glass powder remaining in 50 mesh (a sieve opening of 300 μm) is put in a platinum boat, and kept in a temperature gradient furnace for 24 hours. It is the value which measured the temperature which precipitates.

  The liquid phase viscosity is a value obtained by measuring the viscosity of glass at the liquid phase temperature by a platinum ball pulling method.

  Each sample was cut into a size of 10 mm × 40 mm, and the homogeneity was evaluated by visually observing the transmitted light at an optical path length of 40 mm. Those with good homogeneity were evaluated as “◯” and those with poor homogeneity as “×”.

  For each sample, the solubility was evaluated by observing the time until the glass batch was completely dissolved. Sample No. “X” indicates that the solubility is lower than that of Sample No. 7, Sample No. No. 7 indicating the solubility equivalent to “Δ”, sample No. A sample having slightly better solubility than that of “7” is indicated by “◯”. Those having better solubility than 7 were evaluated as “◎”.

As apparent from Table 2, the sample No. 1-4, the recycling rate of alkali-free glass is 40% or more, the strain point is 585 ° C. or more, the temperature at 10 ^4.0 dPa · s is 1190 ° C. or less, the liquidus temperature is 1070 ° C. or less, and the liquidus viscosity is 10 ^{It was 5.2} dPa · s, and the evaluation of homogeneity and solubility was also good.

  On the other hand, sample No. Since No. 5 comprised a glass batch only with non-alkali glass, the evaluation of homogeneity and solubility was poor. Sample No. Since No. 6 and 7 do not contain alkali-free glass in the glass batch, recycling of the alkali-free glass could not be promoted, and the solubility was inferior.

  The method for producing a glass plate of the present invention is suitable as a method for producing a glass plate for PDP, and is a chalcopyrite thin film polycrystalline solar cell, a dye-sensitized solar cell, a silicon solar cell (single crystal silicon solar cell, It is suitable as a method for producing glass plates for solar cells such as crystalline silicon solar cells, microcrystalline silicon solar cells, and amorphous silicon solar cells), CdTe solar cells, and organic thin film solar cells.

Claims (9)

In the method of manufacturing a glass plate in which a glass raw material is prepared and a glass batch is prepared, and then the glass batch is melted in a glass melting furnace and formed into a glass plate. The plate has a glass composition in mass% in terms of the following oxides: SiO ₂ 40 to 75%, Al ₂ O ₃ 1 to 18%, B ₂ O ₃ 0.1 to 12%, RO (MgO + CaO + SrO + BaO) 5 to 30 %, MgO 0-10%, CaO 0-20%, SrO 0-15%, BaO 0-15%, Na ₂ O + K ₂ O 1-25%, K ₂ O 1-15% The manufacturing method of the glass plate characterized by preparing a raw material.   The method for producing a glass plate according to claim 1, wherein the glass raw material is prepared so that the content of the alkali-free glass in the glass batch is 1 to 90% by mass.   3. The method for producing a glass plate according to claim 1, wherein the alkali-free glass is obtained by pulverizing a plate-like body having a thickness of 0.7 mm or less. The glass raw material is prepared so that the glass plate contains 0.02 to 5% of As ₂ O ₃ + Sb ₂ O ₃ + SnO ₂ + SO ₃ in a mass% in terms of the following oxide as a glass composition. The manufacturing method of the glass plate in any one of Claims 1-3 to do. The method for producing a glass plate according to any one of claims 1 to 4, wherein the glass raw material is prepared so that the temperature at 10 ^4.0 dPa · s is less than 1200 ° C.   A glass raw material is prepared so that a strain point may be 560 ° C or more, The manufacturing method of the glass plate according to any one of claims 1 to 5 characterized by things. The alkali-free glass has a glass composition in mass% in terms of the following oxides: SiO ₂ 55 to 75%, Al ₂ O ₃ 2 to 20%, B ₂ O ₃ 1 to 12%, MgO 0 to 10%, CaO _{0~10%, SrO 0~10%, BaO} 0~15%, 0~1% ZnO, As 2 O 3 0~1%, Sb 2 O 3 0~1%, SnO 2 0~1%, SO 3 It contains 0-0.5%, The manufacturing method of the glass plate in any one of Claims 1-6 characterized by the above-mentioned.   The method for producing a glass plate according to any one of claims 1 to 7, wherein the glass plate is formed by a float process.   The method for producing a glass plate according to any one of claims 1 to 8, wherein the glass plate is a glass plate for plasma display or a glass plate for solar cell.