TWI853473B - Glass - Google Patents

Abstract

The glass of the present invention is characterized in that: as a glass composition, it contains _, in mol%, 67% to 73% of _SiO2 , 10% to 15% of _Al2O3 , 0% to less than 3% of _B2O3 , ₀ % to 0.5% of _Li2O + _Na2O + _K2O , 0% to 8.5% of MgO, 3.5% to 12% of CaO, 0% to 2.5% of SrO, and 1% to 6% of BaO, and the value obtained by _dividing the strain point (°C) by the content of _Al2O3 (mol%) is 51 or more.

Description

Glass

The present invention relates to a glass, and more particularly to a glass suitable for a substrate of an organic electroluminescence (EL) display, a glass carrier used when manufacturing an organic EL element on a polyimide substrate, and the like.

Electronic components such as organic EL displays are used in mobile phone displays and the like because they are thin, have excellent dynamic image display, and consume little power. In addition, organic EL displays using polyimide substrates are being used in various displays because they are lightweight and flexible.

Glass plates are widely used as substrates for organic EL displays. Glass plates are also used as glass carriers used when manufacturing organic EL elements on polyimide substrates. The following properties are mainly required for glass plates for these purposes. (1) A low content of alkali metal oxides is required to prevent the diffusion of alkali ions in the semiconductor material formed in the heat treatment step. (2) Excellent productivity, especially excellent resistance to devitrification or melting properties, is required to make the glass plate cheaper. (3) A high strain point is required to reduce thermal shrinkage in the manufacturing step of p-Si thin film transistors (TFTs). [Prior Art Literature]

[Patent document] [Patent document 1] Japanese Patent List No. 2009-525942

[Problems to be solved by the invention] If the required characteristics (3) are described in detail, there is a heat treatment step of 400°C to 600°C in the film formation step of p-Si·TFT, and in this heat treatment step, the glass plate undergoes a tiny dimensional change called thermal shrinkage. If the amount of thermal shrinkage is large, the pixel pitch of the TFT deviates, which becomes a cause of poor display. In the case of an organic EL display, even a dimensional shrinkage of about several ppm may cause poor display. Furthermore, the higher the heat treatment temperature to which the glass plate is subjected, the greater the thermal shrinkage.

In addition, even when a glass carrier is used when manufacturing an organic EL element on a polyimide substrate, a heat treatment step at the same temperature as when manufacturing an organic EL element on a glass plate is performed. Furthermore, if the thermal shrinkage of the glass plate is large, the thermal shrinkage is transferred to the polyimide substrate, thereby causing a deviation in the pixel pitch.

As described above, it is known that glass sheets that are less susceptible to heat shrinkage are advantageous in these applications. As a method of reducing the amount of heat shrinkage, there is a method of performing annealing treatment near the annealing point after forming the glass sheet. However, the annealing treatment takes a long time, so the manufacturing cost of the glass sheet increases.

As another method, there is a method of increasing the strain point of the glass plate. The higher the strain point, the more difficult it is to produce thermal shrinkage in the manufacturing process of p-Si·TFT. For example, Patent Document 1 discloses a glass plate with a high strain point.

However, high strain point glass generally contains a large amount of refractory SiO ₂ or Al ₂ O ₃ , and thus has low resistance to devitrification and melting properties (especially batch melting properties), making it difficult to stably produce inexpensive and high-quality glass. Therefore, high strain point glass is difficult to satisfy the required properties (2) described above.

The present invention was made in view of the above situation, and its technical problem is to invent glass with small thermal shrinkage and high resistance to devitrification or melting in the manufacturing process of p-Si·TFT. [Means for solving the problem]

The inventors of the present invention have repeatedly conducted various experiments and found that the above-mentioned technical problems can be solved by strictly limiting the glass composition of low-alkali glass and the relationship between Al ₂ O ₃ and the strain point, thereby proposing the present invention. That is, the glass of the present invention is characterized in that: as a glass composition, it contains _{, in mol%, 67% to 73% of SiO2, 10% to 15% of Al2O3, 0% to less than 3% of B2O3 , 0 % to} 0.5% of _Li2O + _Na2O + _K2O , 0% to 8.5% of MgO, 3.5% to 12% of CaO, 0% to 2.5% of SrO, and 1% to ₆ % of BaO, and the value obtained by dividing the strain point (°C) by the content of _Al2O3 (mol%) is 51 or more. Here, " _Li2O + _Na2O + _K2O " means the total amount of _Li2O , _Na2O , and _K2O . "Strain point" refers to the value measured based on the American Society for Testing and Materials (ASTM) C336 method.

In addition, the glass of the present invention is characterized in that, as a glass composition, it contains, in mole %, 67% to 73% SiO ₂ , 10% to 15% Al ₂ O ₃ , 0% to 1.3% B ₂ O ₃ , 0% to 0.5% Li ₂ O + Na ₂ O + K ₂ O, 0% to 3.2% MgO, 3.5% to 12% CaO, 0% to 2% SrO, and 3.5% to 6% BaO, and CaO-(SrO + BaO) is 3.1% or more, the mole ratio CaO/Al ₂ O ₃ is 1.05 or less, and the mole ratio SrO/BaO is 0.03 to 0.50. Here, "CaO-(SrO + BaO)" refers to the value obtained by subtracting the total amount of SrO and BaO from the content of CaO. "CaO/Al ₂ O ₃ " refers to a value obtained by dividing the content of CaO by the content of Al ₂ O _3. "SrO/BaO" refers to a value obtained by dividing the content of SrO by the content of BaO.

In addition, the glass of the present invention is characterized in that: as a glass composition, it contains, in mole %, 67% to 73% of _SiO2 , 12% to ₁₅ % of _{Al2O3 ,} 0% to less than 1.8% of _B2O3 , 0% to less than 0.5% of _Li2O + _Na2O + _K2O , 0% to 6% of MgO, 5% or more of CaO, 0% to 2% of SrO, and 3.5% or more of BaO, and CaO-(SrO+BaO) is 0.7% or more, the mole ratio SrO/BaO is 0.38 or less, the mole ratio (MgO+CaO+SrO+BaO)/ _Al2O3 is _1.09 to 1.70, _and the value obtained by dividing the strain point (°C) by the content of _Al2O3 (mole %) is 55 or more. Here, "(MgO+CaO+SrO+BaO)/ _Al2O3 " refers to a value obtained by dividing the total amount of MgO, CaO, SrO and _BaO by _the content of _Al2O3 .

The glass of the present invention preferably contains, as a glass composition, 67% to 73% SiO ₂ , 10% to 15% Al ₂ O ₃ , 0% to less than 3% B ₂ O ₃ , 0% to 0.5% Li ₂ O + Na ₂ O + K ₂ O, 0% to 8.5% MgO, 3.5% to 12% CaO, 0% to 2.5% SrO, and 1% to 6% BaO in terms of mole %. The reasons for limiting the content range of each component as described above are shown below. In the description of the content range of each component, unless otherwise specified, % means mole %.

_SiO2 is a component that forms the glass skeleton and increases the strain point. It is also a component that improves chemical resistance such as hydrochloric acid. On the other hand, if _SiO2 increases, the solubility will decrease significantly, or the HF etching rate will decrease. Therefore, the preferred lower limit range of _SiO2 is 67% or more, 68% or more, 69% or more, and especially 70% or more, and the preferred upper limit range is 73% or less, especially 72% or less.

Al ₂ O ₃ is a component that increases the strain point or Young's modulus. On the other hand, if Al ₂ O ₃ increases, the solubility of the batch material during initial melting decreases, or the forming temperature increases. The preferred lower limit range of Al ₂ O ₃ is 10% or more, 11% or more, and especially 12% or more, and the preferred upper limit range is 15% or less, 14% or less, 13% or less, and especially 12.5% or less. Furthermore, in the case where a small amount of B ₂ O ₃ is introduced to reduce the solubility or forming viscosity, a relatively large amount of Al ₂ O ₃ can be introduced into the glass composition. On the other hand, in the case where B ₂ O ₃ is almost not contained, too much Al ₂ O ₃ cannot be introduced into the glass composition. In this case, the Al ₂ O ₃ content is preferably as small as possible.

_B2O3 is a component that improves melting properties and resistance to devitrification, and _{is a component that lowers the forming temperature. On the other hand, if a large amount of B2O3 is introduced, the strain point and Young's modulus also decrease. The content of B2O3 is preferably less} than 3%, less than 2.5%, less than 2%, less than 1.8%, less than 1.3%, and particularly less than 0.8%.

As will be described in detail later, the introduction _{of B2O3} is a source of a large amount of water in the glass. Therefore, from the perspective of low water content, the content of _B2O3 is preferably as low as possible. Furthermore, when the glass sheet is manufactured by complete _electric melting without combustion, the lower the content _{of B2O3} , the easier it is for the glass batch to spread evenly in the melting furnace, which can improve the homogeneity of the molten glass.

Li ₂ O, Na ₂ O, and K ₂ O are components that improve melting properties and reduce the resistivity of molten glass. However, if Li ₂ O, Na ₂ O, and K ₂ O are increased, there is a concern that semiconductor materials may be contaminated by diffusion of alkali ions. Therefore, the total amount of Li ₂ O, Na ₂ O, and K ₂ O is preferably 0% to 0.5%, 0% to less than 0.5%, 0.01% to 0.3%, 0.02% to 0.2%, and particularly 0.03% to less than 0.1%. In addition, the content of Na ₂ O is preferably 0% to 0.3%, 0.01% to 0.3%, 0.02% to 0.2%, and particularly 0.03% to less than 0.1%. The content of K ₂ O is preferably 0% to 0.3%, 0% to 0.2%, and particularly 0% to less than 0.1%.

MgO is a component that improves solubility or Young's modulus. On the other hand, _MgO is a component that lowers the strain point. When _Al2O3 is reduced in order to lower the melting temperature or forming temperature, a large amount of _SiO2 needs to be introduced to maintain a high strain point. In such a composition region containing a large amount of _SiO2 , if a large amount of MgO is introduced, white silica is easily precipitated during forming, and further, the strain point is also easily lowered. Therefore, in this case, the MgO content is preferably as small as possible, and the MgO content is preferably 0% to 8.5%, 0% to 6%, 0% to 5%, 0% to 3.2%, 0% to 3%, and especially 0% to 1%. In addition, when a small _amount of _B2O3 is introduced to lower the melting temperature or the forming temperature, the content of _SiO2 can be relatively small and the content of _Al2O3 can be relatively large. In this case, it is preferred to actively introduce _MgO , and the content of MgO is preferably 1% to 8.5%, 2% to 6%, and particularly 2.5% to 5%.

CaO is a component that improves the melting property or the solubility of the batch. In addition, CaO is a component among alkaline earth metal oxides that reduces the raw material cost because the introduced raw materials are relatively cheap. It is also a component that suppresses the precipitation of devitrified crystals containing Mg. On the other hand, if CaO increases, feldspar-based devitrified crystals containing Ca (such as calcite feldspar) are likely to precipitate during molding. Therefore, the CaO content is preferably 3.5% to 12%, 4% to 11%, 5% to 11%, and especially 5.5% to 11%.

SrO is a component that makes it difficult to precipitate white silica during molding, and is a component that does not reduce the strain point much and reduces the melting temperature. On the other hand, if SrO increases, the density increases and the Young's modulus tends to decrease. In addition, in the composition region where calcite, which is the primary phase, is easily precipitated, if SrO increases, the liquidus temperature decreases and the productivity of the glass plate tends to decrease. Therefore, the SrO content is preferably 0% to 2.5%, 0% to 2%, and particularly 0.1% to 1.3%.

BaO is a component in alkaline earth metal oxides that suppresses the precipitation of devitrified crystals such as aluminum-rich andalusite or calcite containing Al during molding. On the other hand, if BaO increases, the density increases and the Young's modulus tends to decrease. The preferred lower limit range of BaO is 1% or more, 2% or more, 3% or more, and especially 3.5% or more, and the preferred upper limit range is 12% or less, 11% or less, 10% or less, 8% or less, and especially 6% or less.

Alkali metal oxides are very important components for improving strain point, devitrification resistance, and solubility. If there are few alkali metal oxides, the strain point will rise, but during forming, _{Al2O3 -} based devitrification crystals will easily precipitate, and the high-temperature viscosity will increase, and the solubility will easily decrease. Therefore, the ratio of the total amount of alkali metal oxides (MgO+CaO+SrO+BaO) to the content of _Al2O3 becomes very important. Specifically, if _the molar ratio (MgO+CaO+SrO+BaO)/ _Al2O3 becomes larger, the solubility or formability will increase, but the strain point will tend to decrease. Conversely _, if this value becomes smaller, there is a tendency that the strain point becomes higher, but the solubility or formability decreases. Therefore, the preferred lower limit range of the _molar ratio (MgO+CaO+SrO+BaO)/ _Al2O3 is 0.95 or more, 1.00 or more, 1.05 or more, and particularly 1.09 or more, and the preferred upper limit range is 1.70 or less.

The molar ratio of _CaO / _Al2O3 is one of the important indicators for ensuring melting properties and maintaining a high strain point. In the composition region containing a large amount of CaO, it is important to design the composition so that the strain point does not decrease. Moreover, _Al2O3 is the main component for increasing the strain point in addition to _SiO2 in alkaline earth aluminosilicate glass. From these viewpoints, the molar ratio _{of CaO/Al2O3 is} preferably 1.09 or less, 1.07 or less, 1.05 or less, and particularly 0.25 to _1.05 .

In order to reduce the manufacturing load and produce glass with a high strain point, the mixing ratio of the four components of the alkaline earth metal oxide becomes very important. From this point of view, CaO-(SrO+BaO) is preferably -3% or more, -1% or more, 0% or more, 0.7% or more, 2% or more, and especially 3.1% to 15%. If CaO-(SrO+BaO) increases, the melting temperature or the forming temperature decreases, and the productivity of the glass sheet can be improved.

In the composition region containing a large amount of CaO, it becomes important to limit the molar ratio SrO/BaO from the viewpoint of devitrification resistance. Specifically, in the composition region containing a large amount of CaO, as mentioned above, calcite as the primary phase is easily precipitated. Among the alkaline earth metal oxides, SrO is a component that increases the liquidus temperature of calcite, and BaO is a component that lowers the liquidus temperature of calcite. Therefore, the smaller the molar ratio SrO/BaO, the lower the liquidus temperature of calcite. However, if SrO is not introduced at all, devitrified crystals such as white silica are easily precipitated during forming. In view of the above, the preferred lower limit range of the molar ratio SrO/BaO is above 0, especially above 0.03, and the preferred upper limit range is below 0.70, below 0.63, below 0.50, especially below 0.38.

In addition to the above components, for example, the following components may also be introduced.

ZnO is a component that improves solubility, but if ZnO increases, the glass is prone to devitrification and the strain point is prone to decrease. Therefore, the ZnO content is preferably 0% to 5%, 0% to 3%, 0% to 0.5%, and particularly 0% to 0.2%.

_P2O5 is a component that lowers the liquidus temperature of Al-based devitrified crystals, but _{if P2O5 increases, the strain point decreases, and white silica is easily precipitated during forming. Therefore, the content of P2O5 is preferably 0 %} to 1.5%, 0% to 1.2%, and particularly 0% to less than 0.1%.

_TiO2 is a component that reduces high temperature viscosity, improves solubility, and inhibits solarization. However, if _TiO2 increases, the glass will be colored and the transmittance will tend to decrease. Therefore, the content of _TiO2 is preferably 0% to 5%, 0% to 3%, 0% to 1%, 0% to 0.1%, and especially 0% to 0.02%.

ZrO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , and La ₂ O ₃ have the effect of increasing the strain point, Young's modulus, etc. However, if these components increase in amount, the density tends to increase. Therefore, the contents of ZrO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , and La ₂ O ₃ are preferably 0% to 5%, 0% to 3%, 0% to 1%, 0% to less than 0.1%, and particularly 0% to less than 0.05%, respectively. Furthermore, the total amount of Y ₂ O ₃ and La ₂ O ₃ is preferably less than 0.1%.

SnO ₂ is a component that has a good clarification effect in the high temperature range, is a component that increases the strain point, and is a component that reduces the high temperature viscosity. The content of SnO ₂ is preferably 0% to 1%, 0.001% to 1%, 0.01% to 0.5%, and especially 0.05% to 0.3%. If SnO ₂ increases, devitrified crystals of SnO ₂ are easily precipitated during forming.

As long as the glass properties are not damaged, _F2 , _Cl2 , _SO3 , C or metal powder such as Al, Si, etc. can be added up to 2% as a clarifier. In addition, _CeO2 , etc. can also be added up to 1% as a clarifier.

As ₂ O ₃ and Sb ₂ O ₃ are effective as clarifiers. The glass of the present invention does not completely exclude the introduction of these components, but from an environmental point of view, it is better not to use these components as much as possible. Furthermore, if As ₂ O ₃ increases, there is a tendency for the light exposure resistance to decrease, so its content is preferably 0.1% or less, and it is ideal that it is substantially free of As 2 O 3. Here, "substantially free of As ₂ O ₃ " means that the content of As ₂ O ₃ in the glass composition is less than 0.05%. In addition, the content of Sb ₂ O ₃ is preferably 0.2% or less, especially 0.1% or less, and it is ideal that it is substantially free of Sb 2 O 3. Here, "substantially free of Sb ₂ O ₃ " means that the content of Sb ₂ O ₃ in the glass composition is less than 0.05%.

Fe ₂ O ₃ is a component that reduces the resistivity of molten glass. The content of Fe ₂ O ₃ is preferably 0% to 0.2%, 0.001% to 0.1%, 0.005% to 0.05%, and particularly 0.008% to 0.015%. If the content of Fe ₂ O ₃ is small, it is difficult to enjoy the above effect. On the other hand, if the content of Fe ₂ O ₃ increases, the transmittance in the ultraviolet range is likely to decrease, and in the manufacturing step of the display, the irradiation efficiency when using a laser in the ultraviolet range is likely to decrease. Furthermore, when performing electric melting, it is preferred to actively introduce Fe ₂ O _3. In this case, the content of Fe ₂ O ₃ is preferably 0.005% to 0.03%, 0.008% to 0.025%, and particularly 0.01% to 0.02%. In addition, when it is desired to increase the transmittance in the ultraviolet range, the content of Fe ₂ O ₃ is preferably 0.020% or less, 0.015% or less, 0.011% or less, and particularly 0.010% or less.

In addition, regarding Fe ₂ O ₃ , the introduction raw material of MgO is the main source of contamination of Fe ₂ O _3. Therefore, from the viewpoint of improving the transmittance in the ultraviolet range, it is preferable to reduce the content of MgO as much as possible.

Cl has the effect of promoting the melting of low-alkali glass. If Cl is added, the melting temperature can be lowered and the effect of the clarifier can be promoted. In addition, Cl has the effect of reducing the β-OH value of the molten glass. However, if Cl increases, the strain point decreases and the environmental load increases. Therefore, the Cl content is preferably less than 0.5%, especially 0.001% to 0.2%. Furthermore, as the introduction raw material of Cl, chlorides of alkaline earth metal oxides such as strontium chloride or raw materials such as aluminum chloride can be used.

The glass of the present invention preferably has the following properties.

The strain point is preferably 730° C. or higher, 735° C. or higher, 740° C. or higher, and particularly preferably 745° C. or higher. If the strain point is low, the glass plate is easily thermally shrunk during the manufacturing process of the p-Si·TFT.

In order to obtain glass with low thermal shrinkage and high melting point in the manufacturing process of p- _Si ·TFT, it is important to increase the strain point and the solubility of the batch material at the same time. On the other hand, _Al2O3 is a component that greatly reduces the solubility of the batch material. Therefore, from the above point of view, it is important to increase the value obtained by dividing _the strain point (°C) by the content (mol%) of _Al2O3 , and the value obtained by dividing _the strain point (°C) by the content (mol%) of _Al2O3 is preferably 51 or more, 53 or more, and especially 55 to 80.

The density is preferably 2.71 g/cm ³ or less, 2.69 g/cm ³ or less, 2.67 g/cm ³ or less, and particularly 2.64 g/cm ³ or less. If the density is high, the Young's modulus becomes higher, the glass is easily bent due to its own weight, and when used as a substrate, the mass of the organic EL display increases.

If the β-OH value is reduced, the strain point can be increased. The β-OH value is preferably 0.30/mm or less, 0.25/mm or less, 0.20/mm or less, 0.15/mm or less, and especially 0.10/mm or less. If the β-OH value increases, the strain point tends to decrease. Furthermore, if the β-OH value is excessively reduced, there is a risk that Cl in the glass will become excessive. Therefore, the β-OH value is preferably 0.01/mm or more, especially 0.02/mm or more.

The following methods can be cited as methods for reducing the β-OH value. (1) Selecting glass raw materials with low water content. (2) Adding components that reduce the water content in the glass (such as Cl and SO ₃ ). (3) Reducing the water content in the furnace environment. (4) Bubbling N ₂ in the molten glass. (5) Using a small melting furnace. (6) Accelerating the flow rate of the molten glass. (7) Using the electric melting method.

Here, "β-OH value" refers to the value obtained by measuring the transmittance of glass using Fourier transform infrared spectroscopy (FT-IR) and using the following formula. β-OH value = (1/X) log (T ₁ /T ₂ ) X: Glass wall thickness (mm) T ₁ : Transmittance at reference wavelength 3846 cm ^-1 (%) T ₂ : Minimum transmittance near hydroxyl absorption wavelength 3600 cm ^-1 (%)

The liquidus temperature is preferably less than 1320°C, 1300°C or less, 1280°C or less, 1260°C or less, 1240°C or less, and particularly 1220°C or less. If the liquidus temperature is high, devitrified crystals will precipitate during forming by overflow down-drawing, etc., and the productivity of the glass sheet will decrease. In addition, the "liquidus temperature" refers to the value obtained by placing glass powder that passes through a standard sieve of 30 mesh (pore size 500 μm) and remains in 50 mesh (pore size 300 μm) in a platinum boat, keeping it in a temperature gradient furnace for 24 hours, and measuring the precipitation temperature of crystals (primary phase).

The liquidus viscosity is preferably 10 ^4.5 dPa·s or more, 10 ^4.8 dPa·s or more, 10 ^5.0 dPa·s or more, 10 ^5.2 dPa·s or more, and particularly preferably 10 ^5.3 dPa·s or more. If the liquidus viscosity is low, devitrified crystals will precipitate during forming by the overflow down-draw method, etc., and the productivity of the glass sheet will decrease. In addition, the "liquidus viscosity" refers to the value obtained by measuring the viscosity of the glass at the liquidus temperature by the platinum ball pulling method.

The temperature at a high temperature viscosity of 10 ^4.5 dPa·s is preferably less than 1320°C, below 1310°C, below 1305°C, and particularly below 1300°C. The temperature at a high temperature viscosity of 10 ^4.5 dPa·s is equivalent to the forming temperature when forming is performed using the overflow down-draw method. If the forming temperature becomes higher, the latent deformation of the formed body is likely to occur, and high-quality glass sheets cannot be stably produced. It is also possible to produce glass sheets by replacing those that have undergone latent deformation, but the formed body is very expensive, so the manufacturing cost of the glass sheets increases. In addition, the "temperature at a high temperature viscosity of 10 ^4.5 dPa·s" can be measured using the platinum ball pulling method.

When the temperature at a high temperature viscosity of 10 ^2.5 dPa·s is set to η _2.5 and the temperature at a high temperature viscosity of 10 ^4.0 dPa·s is set to η _4.0 , (η _2.5 -η _4.0 )/η _2.5 is preferably 0.158 or more, 0.163 or more, and particularly 0.170 or more. The temperature at a high temperature viscosity of 10 ^2.5 dPa·s is generally an index of meltability, and the lower the temperature, the higher the meltability. However, if the composition design is carried out in pursuit of a high strain point as in the present invention, the temperature at a high temperature viscosity of 10 ^2.5 dPa·s becomes higher no matter what is done. Furthermore, when a heat-resistant metal such as platinum is used in a clarification container (clarification pipe), it is difficult to raise the temperature of the clarification container (clarification pipe) to a temperature sufficient for clarification in such a high melting point glass due to the heat resistance limit of platinum. However, even in this case, if the temperature change relative to the viscosity change near the temperature at the high temperature viscosity of 10 ^2.5 dPa·s is large, the process range becomes wider, which is advantageous in terms of improving bubble quality. In addition, "(η _2.5 -η _4.0 )/η _2.5 "is a value obtained by subtracting the temperature at the high temperature viscosity of 10 ^4.0 dPa·s from the temperature at the high temperature viscosity of 10 ^2.5 dPa·s and dividing it by the temperature at the high temperature viscosity of 10 ^2.5 dPa·s. In addition, the "temperature at which the high temperature viscosity reaches 10 ^2.5 dPa·s" and the "temperature at which the high temperature viscosity reaches 10 ^4.0 dPa·s" can be measured using the platinum ball pulling method.

The specific Young's modulus is preferably 29.5 GPa/g·cm ^-3 or more, 29.7 GPa/g·cm ^-3 or more, 30 GPa/g·cm ^-3 or more, 31 GPa/g·cm ^-3 or more, 31.5 GPa/g·cm ^-3 or more, and particularly 32 GPa/g·cm ^-3 or more. If the specific Young's modulus is lower, the glass plate is easily bent due to its own weight, and the glass plate is easily broken during the film formation step of the p-Si·TFT. In addition, the "specific Young's modulus" is a value obtained by dividing the Young's modulus by the density. In addition, the "Young's modulus" can be measured using a well-known resonance method.

The HF etching rate is preferably 0.8 μm/min or more, 0.9 μm/min or more, and particularly 1.0 μm/min or more. When a glass plate is used as a substrate for a portable terminal or the like, thinning (slimming) is achieved by etching with hydrofluoric acid (HF). If the HF etching rate is low, thinning takes time, which becomes a factor in increasing costs. Here, the "HF etching rate" refers to the etching depth when etching is performed on a mirror-polished glass surface using a 10 mass% HF aqueous solution at 20°C for 30 minutes.

The glass of the present invention is preferably in the shape of a flat plate and has an overflow converging surface in the center of the plate thickness direction. That is, it is preferably formed by an overflow down-draw method. The so-called overflow down-draw method is a method in which molten glass overflows from both sides of a wedge-shaped refractory material, and the overflowing molten glass converges at the lower end of the wedge, and extends downward to be formed into a flat plate shape. In the overflow down-draw method, the surface that is to become the surface of the glass plate does not contact the refractory material, but is formed in a free surface state. Therefore, unpolished glass plates with good surface quality can be manufactured inexpensively. Furthermore, it is also easy to increase the area or thin the wall.

In addition to the overflow down-draw method, for example, a glass sheet may be formed by a slot down method, a redraw method, a float method, or a roll out method.

In the glass of the present invention, the wall thickness (plate thickness in the case of a glass plate) is not particularly limited, but is preferably 1.0 mm or less, 0.7 mm or less, 0.5 mm or less, and particularly 0.05 mm to 0.4 mm. The smaller the wall thickness, the easier it is to make the organic EL display lighter. Furthermore, the wall thickness can be adjusted by the flow rate or forming speed (plate drawing speed) during glass manufacturing.

The method for industrially manufacturing the glass of the present invention preferably includes: a melting step, in which a glass batch is put into a melting furnace and heated by electric heating using a heating electrode to obtain a molten glass, wherein the glass batch is prepared in _a manner that contains, as a glass composition, 67% _{to 73% SiO2, 10% to 15% Al2O3, 0% to less than 3% B2O3 , 0 %} to 0.5% _Li2O + _Na2O + _K2O , 0% to 8.5% MgO, 3.5% to 12% CaO, 0% to 2.5% SrO, and 1% to 6% BaO in mole percentage; and a forming step, in which the obtained molten glass is formed into a flat plate-shaped glass with a plate thickness of 0.1 mm to 0.7 mm using an overflow down-draw method.

The manufacturing steps of glass sheets generally include a melting step, a clarification step, a supply step, a stirring step, and a forming step. The melting step is a step of melting a glass batch mixed with glass raw materials to obtain molten glass. The clarification step is a step of clarifying the molten glass obtained in the melting step by using a clarifier or the like. The supply step is a step of transferring the molten glass between the steps. The stirring step is a step of stirring and homogenizing the molten glass. The forming step is a step of forming the molten glass into a plate-shaped glass. Furthermore, steps other than those described above, such as a state adjustment step of adjusting the molten glass to a state suitable for forming, may be incorporated into the stirring step as needed.

In the case of industrial production of previous low-alkali glass, it is usually melted by heating with a combustion flame of a burner. The burner is usually arranged above the melting kiln, and as fuel, a fossil fuel is used, specifically a liquid fuel such as heavy oil or a gas fuel such as liquefied petroleum gas (LPG). The combustion flame can be obtained by mixing the fossil fuel with oxygen. However, in this method, since a large amount of water is mixed into the molten glass during melting, the β-OH value tends to increase. Therefore, when manufacturing the glass of the present invention, it is preferably to perform electric heating using a heating electrode, and it is more preferably not to perform heating using the combustion flame of a burner, but to melt by electric heating using a heating electrode, that is, complete electric melting. Thus, it is difficult for water to be mixed into the molten glass during melting, so it is easy to limit the β-OH value to 0.30/mm or less, 0.25/mm or less, 0.20/mm or less, 0.15/mm or less, and especially 0.10/mm or less. Furthermore, if electric heating is performed using a heating electrode, the amount of energy per unit mass used to obtain the molten glass is reduced, and the molten volatiles are reduced, so the environmental load can be reduced.

Furthermore, regarding the electric heating, the less water content in the glass batch, the easier it is to reduce the water content in the glass sheet. Moreover, the introduction raw material _{of B2O3} tends to become the largest source of water mixing. Therefore, from the perspective of manufacturing a glass sheet with low water content, it is better to make the content of _B2O3 as small as possible. In addition, the less water content in the glass batch, the easier it is for the glass batch to spread evenly in the melting furnace, so it is easy to manufacture _a homogeneous and high-quality glass sheet.

The heating by the electric current of the heating electrode is preferably performed by applying an alternating voltage to the heating electrode installed at the bottom or side of the melting furnace in such a manner that the heating electrode is in contact with the molten glass in the melting furnace. The material used for the heating electrode is preferably one having heat resistance and corrosion resistance to the molten glass, for example, tin oxide, molybdenum, platinum, rhodium, etc. can be used, and molybdenum is particularly preferred from the viewpoint of the degree of freedom of installation in the furnace.

The glass of the present invention has a high resistivity because the content of alkali metal oxide is small. Therefore, when low-alkali glass is heated by electric heating using a heating electrode, current flows not only in the molten glass but also in the refractory material constituting the melting furnace, which may cause the refractory material constituting the melting furnace to be damaged prematurely. In order to prevent the above situation, the refractory material in the furnace is preferably a zirconia-based refractory material with high resistivity, especially a zirconia electrocast brick. In addition, it is preferred to introduce a small amount of components that reduce resistivity (Li ₂ O, Na ₂ O, K ₂ O, Fe ₂ O ₃ , etc.) into the molten glass (glass composition), and it is particularly preferred to introduce a small amount (for example, 0.01 mass% or more, especially 0.02 mass% or more) of Li ₂ O, Na ₂ O, K ₂ O, etc. In addition, the content of Fe ₂ O ₃ is preferably 0.005 mass% to 0.03 mass%, 0.008 mass% to 0.025 mass%, especially 0.01 mass% to 0.02 mass%. Furthermore, the content of _ZrO2 in the zirconia-based refractory is preferably 85% by mass or more, particularly 90% by mass or more. [Example]

The present invention is described below based on the embodiments. However, the following embodiments are for illustration only. The present invention is not limited to the following embodiments in any way.

Tables 1 to 6 show examples of the present invention (sample No. 1 to sample No. 91). In the tables, "N.A." means not measured.

[Table 1] (mol%) No.1 No.2 No.3 No.4 No.5 No.6 No.7 No.8 No.9 No.10 No.11 No.12 No.13 No.14 No.15 SiO ₂ 69.6 69.0 70.3 70.4 69.5 68.6 69.5 68.5 70.0 69.7 69.7 69.7 68.7 68.6 70.0 Al ₂ O ₃ 13.5 14.6 13.2 13.2 13.1 13.2 14.1 14.2 12.7 12.7 12.7 12.7 13.4 13.4 13.1 _{B2O3 ​} 1.9 2.2 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 2.5 2.6 0.4 MgO 1.7 1.7 6.2 6.1 7.1 8.1 6.2 7.1 6.6 6.7 7.2 6.7 2.8 3.3 6.3 CaO 10.3 8.4 3.8 3.8 3.7 3.7 3.8 3.8 4.0 4.1 4.1 4.6 8.5 7.5 3.9 SrO 1.7 1.7 2.1 2.1 2.1 2.1 2.1 2.1 2.2 2.2 1.7 1.7 1.6 1.6 2.1 BaO 1.2 2.3 4.0 4.0 4.0 4.0 4.0 4.0 4.2 4.3 4.3 4.3 2.3 2.8 4.0 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) 7.36 4.49 -2.36 -2.32 -2.34 -2.41 -2.34 -2.28 -2.41 -2.39 -1.87 -1.39 4.56 3.06 -2.27 Sr/Ba 1.33 0.72 0.53 0.53 0.53 0.52 0.53 0.52 0.54 0.52 0.40 0.41 0.71 0.58 0.52 RO/Al 1.11 0.97 1.22 1.21 1.29 1.36 1.13 1.20 1.33 1.37 1.37 1.37 1.13 1.14 1.24 Ca/Al 0.76 0.58 0.29 0.29 0.29 0.28 0.27 0.27 0.32 0.32 0.32 0.36 0.63 0.56 0.30 Ps/Al (℃/mol%) 55.4 51.5 57.7 57.7 57.5 56.9 54.1 53.6 59.4 59.4 59.5 59.4 55.1 55.1 57.7 ρ（g/cm ³ ） 2.546 2.572 2.644 2.645 2.655 2.667 2.653 2.664 2.654 2.661 2.653 2.653 2.571 2.586 2.644 α (×10 ^-7 /℃) 38.9 37.5 38.5 38.5 39.1 39.6 37.9 38.8 39.2 39.9 39.3 39.7 38.6 38.7 38.4 β-OH (mm ^-1 ) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA Ps (℃) 745 752 761 761 755 750 765 759 756 753 754 754 741 740 758 Ta（℃） 803 812 819 820 812 807 822 816 814 812 812 812 800 799 816 Ts（℃） 1032 1043 1054 1053 1043 1033 1052 1042 1048 1043 1043 1043 1031 1032 1049 10 ^4.5 dpa·s（℃） 1281 1294 1315 1312 1296 1278 1304 1288 1305 1299 1298 1297 1283 1284 1307 10 ^4.0 dpa·s（℃） 1341 1354 1377 1374 1356 1337 1364 1347 1367 1361 1359 1358 1343 1344 1368 10 ^3.0 dpa·s（℃） 1498 1510 1540 1537 1515 1492 1522 1503 1529 1524 1519 1518 1503 1504 1528 10 ^2.5 dpa·s（℃） 1598 1610 1643 1643 1617 1590 1623 1602 1633 1629 1622 1620 1604 1606 1630 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.161 0.159 0.162 0.164 0.161 0.159 0.160 0.159 0.163 0.165 0.162 0.162 0.163 0.163 0.161 logη at TL (dpa·s) 4.32 4.58 5.28 5.11 4.75 4.50 4.79 4.60 4.83 4.85 4.75 4.81 4.66 4.86 4.82 E (GPa) 81.9 81.9 83.9 84.1 84.6 85.4 84.9 85.6 84.1 84.1 84.4 84.1 81.9 81.8 84.1 G (GPa) 33.9 33.8 34.8 34.7 35.0 35.3 35.1 35.3 34.7 34.6 34.8 34.7 33.8 33.7 34.5 γ 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.22 0.21 0.21 0.21 0.21 0.22 E/ρ (GPa/g·cm ^-3 ) 32.2 31.9 31.7 31.8 31.9 32.0 32.0 32.1 31.7 31.6 31.8 31.7 31.9 31.6 31.8 HF etching rate (μm/min.) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

[Table 2] (mol%) No.16 No.17 No.18 No.19 No.20 No.21 No.22 No.23 No.24 No.25 No.26 No.27 No.28 No.29 No.30 SiO ₂ 69.3 69.7 69.6 69.6 69.6 69.9 69.9 69.9 69.9 70.0 69.4 69.9 69.9 70.0 70.1 Al ₂ O ₃ 13.5 12.8 12.9 12.9 13.0 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.6 12.5 12.6 _{B2O3 ​} 0.7 1.1 1.0 1.0 1.0 0.5 0.0 0.0 0.0 0.0 0.5 0.7 0.4 1.0 0.6 MgO 6.3 6.3 6.3 6.3 6.8 6.3 6.3 5.8 5.2 4.7 5.3 6.1 5.9 5.7 5.9 CaO 3.9 4.4 4.4 4.9 4.4 4.9 5.4 6.5 7.5 8.5 7.4 4.7 4.7 5.6 5.7 SrO 2.1 2.1 1.6 1.6 1.6 1.6 1.6 1.1 0.6 0.0 0.6 1.3 1.3 0.9 1.0 BaO 4.0 3.5 4.0 3.5 3.5 4.1 4.0 4.0 4.0 4.2 4.0 4.0 4.0 4.0 4.0 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) -2.26 -1.25 -1.26 -0.24 -0.75 -0.76 -0.24 1.27 2.79 4.31 2.77 -0.68 -0.65 0.69 0.65 Sr/Ba 0.52 0.60 0.40 0.46 0.46 0.40 0.40 0.28 0.15 0.00 0.15 0.33 0.33 0.23 0.25 RO/Al 1.21 1.27 1.27 1.27 1.26 1.35 1.39 1.38 1.38 1.38 1.38 1.29 1.27 1.30 1.33 Ca/Al 0.29 0.34 0.34 0.38 0.34 0.39 0.43 0.51 0.59 0.67 0.59 0.37 0.37 0.45 0.46 Ps/Al (℃/mol%) 56.0 58.4 58.2 58.0 57.8 59.9 60.3 60.1 60.3 60.4 59.4 59.4 59.3 59.4 59.7 ρ（g/cm ³ ） 2.648 2.624 2.632 2.617 2.616 2.640 2.649 2.643 2.636 2.632 2.634 2.637 2.649 2.618 2.627 α (×10 ^-7 /℃) 38.5 38.1 38.3 38.0 37.6 39.1 39.5 39.9 40.2 40.4 40.1 38.0 38.2 38.4 39.2 β-OH (mm ^-1 ) NA NA NA NA NA NA NA NA NA NA NA NA NA NA 0.086 Ps (℃) 756 750 750 750 750 753 758 758 758 759 749 748 746 745 750 Ta（℃） 814 808 809 808 808 810 816 815 815 816 806 806 804 804 808 Ts（℃） 1046 1041 1042 1040 1040 1043 1045 1045 1044 1045 1036 1040 1040 1039 1041 10 ^4.5 dpa·s（℃） 1302 1297 1299 1298 1294 1301 1303 1301 1300 1301 1293 1301 1295 1297 1296 10 ^4.0 dpa·s（℃） 1363 1358 1361 1360 1355 1363 1365 1362 1361 1362 1355 1363 1356 1358 1357 10 ^3.0 dpa·s（℃） 1520 1517 1523 1522 1513 1526 1526 1522 1521 1523 1515 1525 1516 1518 1519 10 ^2.5 dpa·s（℃） 1619 1622 1628 1626 1614 1630 1629 1625 1623 1625 1618 1628 1618 1621 1622 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.158 0.163 0.164 0.164 0.160 0.164 0.162 0.162 0.161 0.162 0.163 0.163 0.162 0.162 0.163 logη at TL (dpa·s) 4.94 5.04 5.05 5.04 4.82 4.98 5.02 4.98 4.78 4.67 4.90 4.97 4.95 5.16 5.10 E (GPa) 84.4 83.6 83.3 83.8 83.9 84.0 84.5 84.6 84.4 84.2 84.0 84.0 84.4 83.3 83.4 G (GPa) 34.8 34.3 34.2 34.3 34.4 34.4 34.6 34.7 34.6 34.6 34.4 34.5 34.6 34.2 34.2 γ 0.21 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 E/ρ (GPa/g·cm ^-3 ) 31.9 31.9 31.7 32.0 32.1 31.8 31.9 32.0 32.0 32.0 31.9 31.9 31.9 31.8 31.7 HF etching rate (μm/min.) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

[Table 3] (mol%) No.31 No.32 No.33 No.34 No.35 No.36 No.37 No.38 No.39 No.40 No.41 No.42 No.43 No.44 No.45 SiO ₂ 70.0 70.0 70.1 69.4 69.9 69.5 70.2 70.2 72.8 70.1 70.4 69.1 70.2 72.7 70.2 Al ₂ O ₃ 12.6 12.6 12.5 13.4 13.4 13.4 12.6 12.6 11.1 12.6 12.3 13.7 12.3 11.5 12.4 _{B2O3 ​} 0.7 0.7 0.5 2.8 2.3 2.2 0.7 0.6 0.3 0.7 0.7 1.1 1.1 0.3 0.7 MgO 5.5 5.9 6.1 3.8 4.3 3.8 5.5 5.5 3.2 5.3 5.9 3.4 3.4 2.9 5.3 CaO 6.1 5.8 5.4 6.5 6.0 6.5 6.1 6.1 7.3 6.3 4.5 7.6 7.7 7.3 6.3 SrO 0.4 1.2 1.4 0.6 0.1 1.1 0.4 0.2 0.5 0.4 2.1 0.4 0.4 0.5 0.4 BaO 4.7 3.7 3.8 3.3 3.8 3.3 4.5 4.7 4.7 4.5 4.0 4.7 4.8 4.7 4.6 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) 1.05 0.86 0.12 2.58 2.06 2.06 1.25 1.20 2.08 1.46 -1.68 2.52 2.50 2.16 1.36 Sr/Ba 0.09 0.33 0.37 0.19 0.03 0.34 0.09 0.05 0.11 0.09 0.52 0.09 0.09 0.11 0.09 RO/Al 1.33 1.32 1.34 1.06 1.06 1.10 1.31 1.31 1.41 1.30 1.33 1.17 1.32 1.35 1.33 Ca/Al 0.49 0.46 0.43 0.49 0.45 0.49 0.49 0.49 0.66 0.50 0.36 0.56 0.62 0.64 0.51 Ps/Al (℃/mol%) 59.8 59.6 59.8 55.0 55.4 55.5 59.7 59.6 67.6 59.3 60.7 55.0 60.1 65.8 59.8 ρ（g/cm ³ ） 2.638 2.621 2.628 2.572 2.580 2.589 2.629 2.631 NA 2.629 2.639 2.642 2.637 NA 2.632 α (×10 ^-7 /℃) 39.2 39.1 38.8 36.9 36.6 37.7 39.0 39.1 NA 39.5 39.3 40.2 40.6 NA 39.1 β-OH (mm ^-1 ) 0.086 0.081 NA NA NA NA NA NA 0.075 0.125 0.127 0.130 0.134 0.112 0.136 Ps (℃) 750 750 750 740 744 744 750 751 753 749 748 751 742 754 744 Ta（℃） 809 808 808 799 804 804 809 809 814 807 805 810 801 815 804 Ts（℃） 1042 1041 1042 1035 1041 1039 1043 1044 1059 1043 1044 1045 1040 1062 1042 10 ^4.5 dpa·s（℃） 1299 1296 1298 1295 1301 1299 1300 1301 1328 1302 1305 1300 1303 1339 1301 10 ^4.0 dpa·s（℃） 1360 1357 1359 1358 1363 1361 1362 1362 1393 1364 1367 1361 1366 1405 1363 10 ^3.0 dpa·s（℃） 1521 1520 1518 1524 1524 1521 1524 1524 1566 1525 1530 1519 1531 1578 1527 10 ^2.5 dpa·s（℃） 1623 1625 1620 1631 1629 1624 1628 1628 1675 1627 1633 1620 1636 1693 1632 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.162 0.165 0.161 0.167 0.163 0.162 0.163 0.163 0.168 0.162 0.163 0.160 0.165 0.170 0.165 logη at TL (dpa·s) 5.25 5.06 5.01 4.97 4.90 5.17 5.26 5.16 NA 5.17 5.27 4.64 4.92 NA 5.24 E (GPa) 83.4 83.6 84.0 81.5 81.7 81.7 83.1 83.0 NA 83.1 83.0 82.7 81.5 NA 83.1 G (GPa) 34.2 34.3 34.5 33.4 33.5 33.5 34.1 34.0 NA 34.3 34.2 34.1 33.7 NA 34.2 γ 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 NA 0.21 0.21 0.21 0.21 NA 0.21 E/ρ (GPa/g·cm ^-3 ) 31.6 31.9 31.9 31.7 31.7 31.6 31.6 31.5 NA 31.6 31.5 31.3 30.9 NA 31.6 HF etching rate (μm/min.) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

[Table 4] (mol%) No.46 No.47 No.48 No.49 No.50 No.51 No.52 No.53 No.54 No.55 No.56 No.57 No.58 No.59 No.60 SiO ₂ 70.3 70.2 70.0 69.9 70.0 70.0 69.9 69.3 69.9 69.5 69.2 69.1 69.1 68.9 69.0 Al ₂ O ₃ 12.2 12.4 12.5 12.5 12.6 12.5 12.4 12.6 11.8 13.4 13.4 12.9 13.0 13.5 13.5 _{B2O3 ​} 0.7 0.8 0.9 0.8 0.8 0.8 0.7 0.9 0.8 2.4 2.4 2.4 2.4 2.5 2.0 MgO 5.3 5.9 5.9 5.2 5.2 5.8 5.9 5.1 3.1 2.7 2.8 2.8 2.3 2.8 3.3 CaO 6.3 4.5 4.5 6.3 6.3 4.7 4.5 6.5 7.8 7.3 7.3 7.4 7.9 6.9 7.4 SrO 0.4 2.1 2.1 0.5 0.3 2.1 2.2 0.3 1.0 1.6 0.3 0.3 0.3 0.3 0.3 BaO 4.7 4.0 4.0 4.7 4.8 4.0 4.4 5.2 5.4 3.0 4.4 4.9 4.9 4.9 4.4 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) 1.27 -1.67 -1.68 1.14 1.26 -1.49 -2.09 0.95 1.34 2.65 2.65 2.14 2.65 1.63 2.69 Sr/Ba 0.09 0.52 0.52 0.11 0.06 0.52 0.51 0.06 0.19 0.54 0.07 0.06 0.06 0.06 0.07 RO/Al 1.36 1.33 1.32 1.33 1.31 1.33 1.36 1.35 1.46 1.10 1.10 1.19 1.19 1.10 1.14 Ca/Al 0.52 0.36 0.36 0.50 0.50 0.37 0.36 0.51 0.66 0.54 0.55 0.57 0.61 0.51 0.55 Ps/Al (℃/mol%) 60.8 59.9 59.5 59.5 59.3 59.6 60.1 58.8 62.3 55.5 55.2 56.7 56.6 54.7 54.9 ρ（g/cm ³ ） 2.635 2.640 2.640 2.640 2.639 2.642 2.656 2.655 2.675 2.586 2.607 2.624 2.624 2.620 2.615 α (×10 ^-7 /℃) 39.9 39.2 39.4 39.5 39.2 39.3 40.0 40.5 42.8 38.1 38.4 39.6 40.0 38.7 38.8 β-OH (mm ^-1 ) 0.138 0.137 0.135 0.120 0.113 0.115 0.117 0.097 0.097 0.128 0.123 0.126 0.134 0.136 0.132 Ps (℃) 744 744 744 746 748 745 745 743 738 741 742 734 734 740 743 Ta（℃） 803 803 803 804 806 804 803 802 796 800 802 794 794 800 802 Ts（℃） 1041 1041 1040 1040 1042 1041 1040 1035 1032 1037 1038 1033 1033 1038 1038 10 ^4.5 dpa·s（℃） 1303 1303 1300 1299 1299 1300 1301 1294 1296 1296 1300 1294 1294 1298 1298 10 ^4.0 dpa·s（℃） 1365 1365 1362 1361 1361 1362 1363 1356 1360 1358 1363 1356 1357 1360 1361 10 ^3.0 dpa·s（℃） 1528 1528 1524 1524 1524 1524 1526 1518 1527 1519 1525 1521 1522 1522 1526 10 ^2.5 dpa·s（℃） 1633 1633 1629 1627 1627 1628 1631 1618 1632 1625 1629 1624 1627 1628 1640 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.164 0.164 0.164 0.163 0.163 0.163 0.164 0.162 0.167 0.164 0.163 0.165 0.166 0.165 0.170 logη at TL (dpa·s) 5.27 5.29 5.22 5.21 5.13 5.18 5.14 5.11 5.07 4.97 5.08 5.13 4.96 5.11 4.93 E (GPa) 82.9 83.3 83.3 83.2 83.1 83.2 83.0 82.5 81.2 81.2 80.7 80.1 79.9 80.5 81.6 G (GPa) 34.2 34.3 34.3 34.2 34.2 34.2 34.2 34.1 33.5 33.4 33.3 33.0 32.9 33.1 33.6 γ 0.21 0.21 0.21 0.21 0.21 0.22 0.21 0.21 0.21 0.22 0.21 0.22 0.22 0.22 0.21 E/ρ (GPa/g·cm ^-3 ) 31.5 31.5 31.6 31.5 31.5 31.5 31.3 31.1 30.4 31.4 31.0 30.5 30.4 30.7 31.2 HF etching rate (μm/min.) NA NA NA NA NA 0.96 NA NA NA NA NA NA NA NA NA

[Table 5] (mol%) No.61 No.62 No.63 No.64 No.65 No.66 No.67 No.68 No.69 No.70 No.71 No.72 No.73 No.74 No.75 SiO ₂ 69.0 69.0 72.1 71.0 71.0 72.0 72.1 72.1 72.1 72.1 72.1 71.9 71.1 71.2 71.0 Al ₂ O ₃ 13.5 13.0 10.8 10.9 10.8 10.8 10.8 10.8 10.8 11.8 11.8 11.9 11.8 11.8 11.9 _{B2O3 ​} 2.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 3.3 3.8 0.0 0.0 0.0 0.0 1.0 1.0 2.0 1.0 2.0 3.0 1.0 2.0 3.0 CaO 6.9 6.9 11.5 11.9 11.6 11.6 11.5 10.5 9.5 10.5 9.5 8.6 10.5 9.5 8.6 SrO 0.3 0.3 1.3 0.3 1.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 4.9 4.9 4.2 5.8 5.2 5.2 4.1 5.1 5.2 4.1 4.1 4.2 5.2 5.2 5.2 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) 1.63 1.66 6.03 5.78 5.06 6.09 7.07 5.10 4.06 6.08 5.08 4.09 5.06 4.07 3.07 Sr/Ba 0.06 0.06 0.31 0.05 0.25 0.06 0.07 0.06 0.06 0.07 0.07 0.07 0.06 0.06 0.06 RO/Al 1.14 1.22 1.57 1.65 1.67 1.58 1.57 1.58 1.57 1.35 1.35 1.35 1.44 1.45 1.44 Ca/Al 0.51 0.53 1.06 1.09 1.07 1.07 1.07 0.98 0.88 0.89 0.81 0.72 0.89 0.81 0.72 Ps/Al (℃/mol%) 55.0 56.5 69.3 67.9 68.8 69.4 69.3 69.3 69.0 64.7 64.4 63.8 64.0 64.1 63.4 ρ（g/cm ³ ） 2.630 2.630 2.654 2.704 2.697 2.666 2.631 2.661 2.659 2.623 2.620 2.616 2.668 2.665 2.662 α (×10 ^-7 /℃) 38.9 39.4 44.8 46.7 46.5 45.0 43.5 44.0 43.3 42.0 41.0 40.3 44.0 43.0 42.3 β-OH (mm ^-1 ) 0.117 0.122 0.112 0.119 0.079 0.082 0.081 0.073 0.074 0.073 0.074 0.077 0.078 0.078 0.083 Ps (℃) 742 736 748 741 744 750 750 747 746 764 760 759 755 753 752 Ta（℃） 802 796 805 798 799 807 807 805 804 822 820 818 813 811 810 Ts（℃） 1039 1033 1034 1022 1023 1037 1038 1037 1039 1057 1056 1056 1043 1044 1044 10 ^4.5 dpa·s（℃） 1301 1294 1301 1284 1283 1303 1305 1308 1317 1327 1324 1316 1308 1310 1313 10 ^4.0 dpa·s（℃） 1363 1356 1367 1348 1347 1369 1370 1374 1384 1393 1389 1379 1372 1375 1378 10 ^3.0 dpa·s（℃） 1525 1520 1540 1518 1517 1542 1543 1547 1556 1564 1561 1551 1541 1544 1546 10 ^2.5 dpa·s（℃） 1628 1628 1652 1628 1628 1655 1654 1661 1667 1673 1675 1664 1650 1652 1653 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.163 0.167 0.173 0.172 0.173 0.173 0.172 0.173 0.170 0.167 0.171 0.171 0.168 0.168 0.166 logη at TL (dpa·s) 5.07 5.18 5.15 5.20 5.21 5.20 5.09 5.30 NA 4.63 4.83 4.79 4.63 4.78 4.92 E (GPa) 81.3 81.3 80.7 80.3 80.3 80.2 81.1 80.3 80.8 81.2 81.6 82.1 80.9 81.3 81.7 G (GPa) 33.4 33.4 32.8 33.1 33.1 33.1 33.5 33.2 33.3 33.6 33.8 33.9 33.3 33.5 33.7 γ 0.22 0.22 0.23 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 E/ρ (GPa/g·cm ^-3 ) 30.9 30.9 30.4 29.7 29.8 30.1 30.8 30.2 30.4 31.0 31.1 31.4 30.3 30.5 30.7 HF etching rate (μm/min.) NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

[Table 6] (mol%) No.76 No.77 No.78 No.79 No.80 No.81 No.82 No.83 No.84 No.85 No.86 No.87 No.88 No.89 No.90 No.91 SiO ₂ 71.6 71.1 71.4 71.5 71.7 71.5 71.1 71.2 71.1 71.3 71.1 71.0 71.5 71.8 71.6 71.8 Al ₂ O ₃ 10.9 10.8 10.9 10.9 11.0 11.2 11.2 11.4 11.2 11.2 11.2 11.2 10.8 10.8 10.8 10.8 _{B2O3 ​} 0.0 0.0 0.0 0.0 0.3 0.7 0.3 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.0 0.0 1.0 1.0 CaO 11.5 11.5 11.1 10.6 11.0 10.5 11.1 10.5 11.1 10.5 10.6 10.1 11.1 10.8 10.1 9.8 SrO 0.8 1.3 1.3 1.8 0.8 0.8 1.1 1.1 0.3 1.8 1.3 1.8 1.3 1.3 1.3 1.3 BaO 4.1 4.2 4.2 4.2 4.1 4.1 4.2 4.1 5.2 4.1 4.7 4.7 5.2 5.2 5.2 5.2 _SnO2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ca-(Sr+Ba) 6.60 6.10 5.62 4.60 6.10 5.62 5.81 5.28 5.66 4.58 4.61 3.59 4.63 4.33 3.65 3.34 Sr/Ba 0.19 0.31 0.31 0.43 0.19 0.19 0.26 0.26 0.05 0.43 0.28 0.38 0.25 0.25 0.25 0.25 RO/Al 1.61 1.67 1.62 1.62 1.54 1.47 1.54 1.47 1.57 1.56 1.57 1.57 1.63 1.60 1.63 1.61 Ca/Al 1.06 1.07 1.02 0.97 1.00 0.94 0.98 0.92 0.99 0.94 0.95 0.90 1.03 1.00 0.94 0.91 Ps/Al (℃/mol%) 68.5 68.7 68.4 68.5 67.5 65.9 65.9 64.9 66.7 66.8 66.5 66.5 68.9 69.1 68.9 68.9 ρ（g/cm ³ ） 2.645 2.661 2.654 2.661 2.638 2.631 2.650 2.641 2.672 2.662 2.671 2.679 2.690 2.686 2.686 2.681 α (×10 ^-7 /℃) 44.8 45.5 44.6 44.8 44.1 43.4 44.2 43.4 45.3 44.8 45.0 45.1 46.3 45.7 45.4 44.8 β-OH (mm ^-1 ) 0.083 0.090 0.079 0.076 0.086 0.097 0.090 0.096 0.071 0.069 0.070 0.067 0.070 0.091 0.077 0.088 Ps (℃) 743 743 745 744 743 740 741 740 747 746 744 747 745 746 742 742 Ta（℃） 800 799 802 801 800 799 799 798 803 803 801 804 801 802 799 800 Ts（℃） 1031 1026 1032 1032 1034 1036 1031 1034 1034 1033 1032 1034 1029 1032 1031 1034 10 ^4.5 dpa·s（℃） 1294 1285 1296 1295 1298 1303 1293 1297 1296 1297 1297 1298 1292 1298 1295 1301 10 ^4.0 dpa·s（℃） 1358 1348 1360 1359 1363 1368 1357 1361 1360 1362 1362 1362 1357 1363 1360 1366 10 ^3.0 dpa·s（℃） 1529 1517 1531 1530 1535 1540 1527 1531 1530 1533 1532 1533 1528 1537 1533 1539 10 ^2.5 dpa·s（℃） 1642 1626 1642 1641 1646 1652 1636 1639 1641 1644 1642 1643 1640 1647 1646 1651 (10 ^2.5 -10 ^4.0 )/10 ^2.5 0.173 0.171 0.172 0.172 0.172 0.172 0.171 0.170 0.171 0.172 0.171 0.171 0.173 0.172 0.174 0.173 logη at TL (dpa·s) 4.92 4.88 5.15 5.16 4.81 4.87 4.91 4.91 5.00 4.85 5.02 5.07 5.27 5.27 5.21 5.28 E (GPa) 80.6 80.7 80.6 80.6 80.4 80.2 80.6 80.4 80.6 80.6 80.5 80.5 79.9 80.0 80.3 80.4 G (GPa) 33.3 33.3 33.2 33.3 33.2 33.1 33.3 33.1 33.2 33.3 33.2 33.2 32.9 33.1 33.1 33.2 γ 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 E/ρ (GPa/g·cm ^-3 ) 30.5 30.3 30.4 30.3 30.5 30.5 30.4 30.5 30.1 30.3 30.1 30.1 29.7 29.8 29.9 30.0 HF etching rate (μm/min.) NA NA NA NA NA NA NA NA NA NA NA NA 1.14 1.04 NA NA

First, a glass batch prepared by mixing glass raw materials to obtain the glass composition shown in the table was placed in a platinum crucible and melted at 1600°C to 1650°C for 24 hours. When the glass batch was melted, it was stirred with a platinum stirring rod to homogenize it. Then, the molten glass was poured onto a carbon plate and formed into a plate, and then annealed at a temperature near the annealing point for 1 hour. For each sample obtained, the density ρ, average thermal expansion coefficient α in the temperature range of 30℃ to 380℃, β-OH value, strain point Ps, annealing point Ta, softening point Ts, temperature at high temperature viscosity of 10 ^4.5 dPa·s, temperature at high temperature viscosity of 10 ^4.0 dPa·s, temperature at high temperature viscosity of 10 ^3.0 dPa·s, temperature at high temperature viscosity of 10 ^2.5 dPa·s, liquidus viscosity logη at TL, Young's modulus E, rigidity G, Poisson's ratio γ, specific Young's modulus E/ρ, and HF etching rate were evaluated.

The density ρ is a value measured by the well-known Archimedes method.

The average thermal expansion coefficient α in the temperature range of 30°C to 380°C is a value measured using a dilatometer.

The β-OH value is a value measured by the above method.

The strain point Ps, annealing point Ta, and softening point Ts are values measured based on the methods of ASTM C336 and C338.

The temperatures at high temperature viscosity 10 ^4.5 dPa·s, high temperature viscosity 10 ^4.0 dPa·s, high temperature viscosity 10 ^3.0 dPa·s, and high temperature viscosity 10 ^2.5 dPa·s are values measured by the platinum ball pulling method.

Liquidus viscosity logη at TL is the value obtained by measuring the viscosity of glass at liquidus temperature TL using the platinum ball pulling method. Liquidus temperature TL is the value obtained by placing glass powder that has passed through a standard sieve of 30 mesh (pore size 500 μm) and remained in 50 mesh (pore size 300 μm) in a platinum boat, keeping it in a temperature gradient furnace for 24 hours, and measuring the precipitation temperature of crystals (primary phase).

Young's modulus E and rigidity modulus G are values measured using a known resonance method. Poisson's ratio is a value calculated from Young's modulus E and rigidity modulus G. Specific Young's modulus E/ρ is a value obtained by dividing Young's modulus by density.

The HF etching rate refers to the etching depth of a mirror-polished glass surface when etching was performed using a 10 mass% HF aqueous solution at 20°C for 30 minutes.

As shown in Tables 1 to 6, Samples No. 1 to Sample No. 91 have a small content of alkali metal oxide, a strain point of 734°C or higher, a temperature of 10 ^2.5 dPa·s or lower at a high temperature viscosity of 1693°C, and a liquid phase viscosity of 10 ^4.32 dPa·s or higher. Therefore, it is considered that Samples No. 1 to Sample No. 91 are suitable for substrates of organic EL displays and glass carriers used when manufacturing organic EL elements on polyimide substrates.

Claims (10)

A glass characterized in that: as a glass composition, the _glass contains, in mole %, 67% to 73% _SiO2 , 12.2% to ₁₅ % _Al2O3 , 0.2% to 1.3% _B2O3 , 0% to 0.5% _Li2O + _Na2O + _K2O , 3.4% to 8.5% MgO, 3.5% to 12% CaO, 0% to 2.5% SrO, and 3.5% to 6% BaO, and the value obtained by dividing _the strain point (°C) by the content of _Al2O3 (in mole %) is 51 or more, and the mole ratio _CaO / _Al2O3 is 0.45 or less. The glass as claimed in claim 1, wherein the composition contains 12.6% to 15% Al ₂ O ₃ in mol%. The glass as claimed in claim 1, wherein the composition contains 12.8% to 15% Al ₂ O ₃ in mol%. The glass as claimed in claim 1, wherein the composition contains 13.1% to 15% Al ₂ O ₃ in mol%. The glass as described in any one of claims 1 to 3, wherein the composition contains 0.2% to 1% B ₂ O ₃ in terms of mol%. The glass as described in any one of claims 1 to 3, wherein the composition contains 0.2% to 0.6% B ₂ O ₃ in mol%. The glass as described in any one of claims 1 to 3, wherein the composition contains 0.2% to 0.4% B ₂ O ₃ in mol%. The glass as described in any one of claims 1 to 3 contains 3.8% to 6% BaO in terms of mole %. The glass as described in any one of claims 1 to 3 contains 4% to 6% BaO in terms of mole %. The glass as described in any one of claims 1 to 3 contains 4.3% to 6% BaO in terms of mole %.