WO2013032290A2 - Alkali-free glass and method for manufacturing same - Google Patents

Abstract

Disclosed are a composition for alkali-free glass which contains no alkali metal oxides, and a method for manufacturing said glass. By weight % on the basis of oxides, the alkali-free glass according to the present invention contains: 61 to 73% of SiO₂; 0.5 to 3.9% of B₂O₃; 3.5 to 13.5% of Al₂O₃; 9 to 13% of MgO; 1 to 8% of CaO; and 4 to 10% of SrO, and contains substantially no alkali metal oxides.

Description

Alkali-free glass and its manufacturing method

This application is a priority application for Korean Patent Application No. 10-2011-0089112, filed September 2, 2011, and Korean Patent Application No. 10-2012-0096357, filed August 31, 2012. All the contents disclosed in the specification and drawings of this application are incorporated in this application by reference.

TECHNICAL FIELD This invention relates to the glass manufacturing technique. More specifically, it is related with the alkali free glass composition which does not contain the alkali metal oxide, and the manufacturing method of such glass.

Glass, especially flat glass, is used in various fields such as window glass, window screens of vehicles, mirrors, and the like, and its type is also being developed and used in various ways.

In particular, alkali-free glass substrates are widely used in flat panel display devices such as LCDs, PDPs, and organic ELs. In the case of the alkali glass substrate containing an alkali metal oxide component, since alkali metal ions in a glass substrate can diffuse in a thin film and deteriorate a film | membrane characteristic, alkali free glass is widely used for display rather than alkali glass.

By the way, in the case of such a glass for flat panel display substrates, various product characteristics are calculated | required.

For example, in the case of glass for flat panel displays, weight reduction should be ensured. In particular, in recent years, as display devices such as TVs and monitors are gradually enlarged, the area of the substrate glass used therein is also increasing. In this case, since the warping phenomenon of the substrate glass due to the load of the substrate glass itself can be further increased, in order to prevent this, the substrate glass needs to be manufactured to have a lighter weight. In addition, the substrate glass may be used in a small portable display device such as a mobile phone, a PDP, a notebook computer, and even in this case, it is required to reduce the weight of the substrate glass.

In addition, in the case of glass for flat panel display substrates, appropriate meltability (melting property) must be ensured. If the meltability of the glass is lowered, energy and time required for melting the glass are increased, and defects such as bubbles and foreign matters are likely to occur in the glass. In addition, since bubbles or foreign matter in the glass interfere with light transmission, the quality of the glass for the display device may be greatly degraded.

In addition, in the case of glass for flat panel display substrates, heat resistance must be ensured. For example, in the manufacturing process of a flat panel display device such as a TFT-LCD, various heat treatment processes may be performed. In this process, the glass substrate may be exposed to rapid heating and quenching environments. In this situation, when the heat resistance is not secured to the glass, deformation or warping of the glass may occur, and the glass substrate may be broken due to the tensile stress caused by the heat. Moreover, in the case of the glass for TFT-LCD, when the heat resistance is low, a difference in thermal expansion may occur between the TFT material and the pixel pitch of the TFT may be shifted, which may cause display defects.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide an alkali free glass and a method of manufacturing the same, which are light, have good meltability, and are easy to process.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

Glass according to the present invention for achieving the above object is an alkali-free glass, in the basis of the oxide-based weight% display, SiO ₂ 61-73%; B ₂ O ₃ 0.5-3.9%; Al ₂ O ₃ 3.5-13.5%; MgO 9-13%; CaO 1-8%; And 4-10% of SrO and substantially no alkali metal oxide.

Preferably, the said alkali free glass does not contain BaO substantially.

Also preferably, the alkali free glass has a density of less than 2.55 g / cm ³ , a coefficient of thermal expansion of 3.0 × 10 ⁻⁶ / K to 4.5 × 10 ⁻⁶ / K, and a temperature at viscosity 10 ² dPas of 1600 And a temperature at a viscosity of 10 ⁴ dPas is less than 1250 ° C.

In addition, the display device according to the present invention for achieving the above object includes the above-described glass.

Preferably, the display device is a liquid crystal display device.

In addition, the glass manufacturing method according to the present invention for achieving the above object, as an alkali-free glass manufacturing method, in terms of the oxide-based weight% display, SiO ₂ 61-73%; B ₂ O ₃ 0.5-3.9%; Al ₂ O ₃ 3.5-13.5%; MgO 9-13%; CaO 1-8%; And combining the glass raw material so as to contain 4-10% of SrO and substantially no alkali metal oxide.

Preferably, the glass raw material combining step combines the glass raw materials so as not to substantially contain BaO.

Also preferably, the alkali free glass produced by the glass manufacturing method has a density of less than 2.55 g / cm ³ , a thermal expansion coefficient of 3.0 × 10 ⁻⁶ / K to 4.5 × 10 ⁻⁶ / K, and a viscosity of 10 The temperature at ² dPas is less than 1600 ° C and / or the temperature at viscosity 10 ⁴ dPas is less than 1250 ° C.

According to this invention, the alkali free glass which does not contain the alkali metal oxide component substantially is provided.

In particular, according to one embodiment of the present invention, a low density alkali free glass may be provided. Therefore, even in a glass substrate having a large area, it is possible to reduce the warping phenomenon due to its own weight, thereby meeting the trend of increasing the size of display devices such as TVs and monitors. In addition, even in the case of a small portable device such as a mobile phone or a notebook using a glass substrate, the weight can be reduced, so that portability can be improved.

In addition, according to an embodiment of the present invention, the T2, which is a temperature at a viscosity of 10 ² dPas, may be lowered, thereby improving the meltability of the glass, and the T4, which is a temperature at a viscosity of 10 ⁴ dPas, is lowered, thereby lowering the processing temperature of the glass. Processing can be facilitated. In addition, since the melting temperature and processing temperature of the glass can be lowered in this way, the energy, time, etc. required for melting and processing the glass can be reduced.

And, according to an embodiment of the present invention, an alkali free glass having a low coefficient of thermal expansion may be provided. Therefore, even if the glass is exposed to various heat treatment environments during the manufacturing process of the flat panel display device such as the TFT-LCD, it is possible to prevent the phenomenon such as heat shrinkage, deformation, warpage, and cracking. In addition, the thermal expansion coefficient of the alkali free glass is similar to the thermal expansion coefficient of the TFT material, thereby effectively preventing display defects and the like caused by the pixel pitch shifting.

Therefore, in the case of the alkali free glass which concerns on this invention, it is more preferable to be used for flat panel displays, such as a liquid crystal display (LCD), a PDP, and an organic electroluminescent display.

The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the detailed description of the present invention, serve to further understand the technical spirit of the present invention. It should not be construed as limited to.

1 is a flowchart schematically showing a method for producing an alkali free glass according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described herein are only the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, and various equivalents and modifications that may substitute them at the time of the present application may be used. It should be understood that there may be.

The glass which concerns on this invention is an alkali free glass which does not contain an alkali metal oxide substantially. Here, substantially free of an alkali metal oxide means that the content of the alkali metal oxide is not included in the glass at all, or even partially contained, so that its content is extremely small compared to the other components and can be neglected as a composition component of the glass. If so, it means. For example, when an alkali metal oxide such as Li ₂ O, Na ₂ O and K ₂ O is contained in an amount of 0.2 wt% or less as the glass composition component, it can be said that the alkali metal oxide is not substantially contained.

The alkali-free glass according to the present invention include _{SiO 2, B 2 O 3,} Al 2 O 3, MgO, CaO , and SrO in the composition components.

In particular, alkali-free glass according to the invention may contain 61-73% of SiO ₂ as an oxide based on weight percentages. SiO ₂ is a network structure oxide that forms glass and may contribute to increasing the chemical resistance of the glass and to having an adequate coefficient of thermal expansion. However, when SiO ₂ is contained too high, the coefficient of thermal expansion may be too low and the devitrification characteristics of the glass may be deteriorated. On the other hand, when SiO ₂ is contained too low, the chemical resistance may decrease, the density may increase, the coefficient of thermal expansion may increase, and the strain point may decrease. Accordingly, the alkali-free glass according to the present invention include SiO ₂ for 61-73% by weight. Preferably, the SiO ₂ is preferably contained 64 to 72% by weight. More preferably, the SiO ₂ is preferably contained 66 to 71% by weight.

Further, the alkali-free glass according to the invention may contain 0.5 ~ 3.9% of B ₂ O ₃ as oxides based on weight percentages. B ₂ O ₃ is a network structure oxide of glass, which can contribute to improving the dissolution reactivity of the glass, reducing the coefficient of thermal expansion, improving the devitrification, improving chemical resistance such as BHF resistance, and lowering the density. However, when B ₂ O ₃ is contained too high, the acid resistance of the glass may be lowered, the density may be increased, and the strain point may be lowered, thereby deteriorating heat resistance. On the other hand, when B ₂ O ₃ is contained too low, the effect of addition is difficult to achieve properly. Accordingly, the alkali-free glass, comprising 0.5 to 3.9% by weight of B ₂ O ₃ in accordance with the present invention. Preferably, the B ₂ O ₃ is preferably contained 1 to 3.9% by weight. More preferably, the B ₂ O ₃ It is preferably contained 3 to 3.9% by weight.

Further, the alkali-free glass according to the invention may contain 3.5 ~ 13.5%, an Al ₂ O ₃ as oxides based on weight percentages. Al ₂ O ₃ increases the high temperature viscosity, chemical stability, thermal shock resistance and the like of the glass and may contribute to increase the strain point and Young's modulus. However, when Al ₂ O ₃ is contained too high, it is possible to reduce the devitrification characteristics, hydrochloric acid resistance and BHF resistance and increase the viscosity. On the other hand, when Al ₂ O ₃ is contained too low, its addition effect is difficult to achieve properly and the elastic modulus may be low. Accordingly, the alkali-free glass, comprising 3.5 ~ 13.5% by weight of Al ₂ O ₃ in accordance with the present invention. Preferably, Al ₂ O ₃ is preferably contained 4 to 12% by weight. More preferably, the Al ₂ O ₃ is preferably contained 4 to 9% by weight.

Here, the alkali-free glass according to the present invention, it is preferable to contain an SiO ₂ + Al ₂ O ₃ the total content of SiO ₂ and Al ₂ O ₃ 72 ~ 79% by weight. This is because the effect of containing SiO ₂ and Al ₂ O ₃ can be further improved in such a concentration range, and deterioration of the thermal expansion coefficient and devitrification characteristics can be prevented.

In addition, the alkali free glass which concerns on this invention can contain 9 to 13% of MgO by oxide-based weight% display. MgO is an alkaline earth metal oxide and does not increase the coefficient of thermal expansion and can contribute to improving meltability without significantly lowering the strain point. In particular, MgO can reduce the density of the glass, which can greatly contribute to the weight reduction of the glass. However, when MgO is contained too high, the devitrification characteristic of glass may fall, and acid resistance and BHF resistance may fall. On the other hand, when MgO is contained too low, it is difficult to achieve the above-mentioned MgO addition characteristic. Thus, the alkali free glass according to the present invention comprises 9 to 13% by weight of MgO. Preferably, the MgO is preferably contained in 9.5 to 12% by weight. More preferably, the MgO is contained 10 to 11% by weight.

In addition, the alkali free glass which concerns on this invention can contain CaO 1 to 8% by an oxide reference weight% display. CaO, like MgO, is an alkaline earth metal oxide that can contribute to lowering the density and coefficient of thermal expansion, not significantly reducing the strain point, and improving meltability. However, when CaO is contained too high, the density and the coefficient of thermal expansion can be large and the chemical resistance such as BHF resistance can be degraded. On the other hand, when CaO is contained too low, the characteristic improvement effect by addition of CaO mentioned above is hard to achieve correctly. Therefore, the alkali free glass according to the present invention contains 1 to 8% by weight of CaO. Preferably, the CaO is preferably contained 4 to 8% by weight. More preferably, the CaO is contained 5 to 7.5% by weight.

In addition, the alkali free glass which concerns on this invention can contain 4-10% of SrO by the oxide basis weight% display. SrO is an alkaline earth metal oxide and can contribute to improvement of the devitrification property and acid resistance of glass. However, when SrO is contained too high, the coefficient of thermal expansion or density may increase, and devitrification characteristics may deteriorate. On the other hand, when SrO is contained too low, the effect of adding SrO as described above is difficult to be properly achieved. Thus, the alkali free glass according to the present invention comprises 4 to 10% by weight of SrO. Preferably, the SrO is preferably contained 4 to 8% by weight. More preferably, the SrO is preferably contained 4 to 6% by weight.

Here, it is preferable that the alkali free glass which concerns on this invention contains 15-26 weight% of MgO + CaO + SrO which is a total content of MgO, CaO, and SrO. This is because the effect of containing alkaline earth metal oxides in this concentration range can be improved, and the devitrification property may not be degraded. More preferably, the MgO + CaO + SrO is preferably 17 to 24% by weight. Most preferably, the MgO + CaO + SrO is 19 to 22% by weight.

Preferably, the alkali free glass according to the present invention may be substantially free of BaO. BaO may play a role of improving chemical resistance and devitrification characteristics, but it is not preferable in terms of increasing the density of glass and environmentally. In the case of the alkali-free glass according to an embodiment of the present invention, since it does not contain such BaO, it is possible to lower the density of the glass and to manufacture more environmentally friendly glass.

Also preferably, the alkali free glass according to the present invention may have a density of less than 2.55 g / cm ³ . According to this embodiment, the density of the glass may be low and it may be easy to achieve the weight reduction of the glass article. In particular, in a situation where the glass area is gradually increased due to the enlargement of the apparatus to which the glass is applied, when the density of the glass is lowered, it is possible to reduce the warpage phenomenon due to the glass's own load and to reduce the weight of the apparatus to which the glass is applied. In addition, the weight of the glass itself can also be reduced for small portable devices and devices, thereby improving portability.

Also preferably, the alkali free glass according to the present invention may have a coefficient of thermal expansion (CTE) of 3.0 × 10 ⁻⁶ / K to 4.5 × 10 ⁻⁶ / K. According to this embodiment, the thermal expansion coefficient is low, and the thermal shock resistance is excellent. Therefore, even if various heat treatment processes are repeatedly performed on the glass substrate, problems such as heat shrinkage, warpage, and deformation can be prevented from occurring. In addition, since the thermal expansion coefficient is similar to that of the TFT material, it is possible to prevent display defects due to the TFT material and the thermal expansion difference and the like during TFT-LCD manufacture using the glass according to the present invention.

Also preferably, in the alkali free glass according to the present invention, T _{2, which} is a temperature at a viscosity of 10 ² dPas, may be less than 1600 ° C. More preferably, the alkali-free glass according to the present invention, the temperature of T ₂ in the viscosity can be less than 10 ² dPas 1550 ℃. According to this embodiment, since the T ₂ associated with the melting (melting) temperature of the glass is low, the melting property of the glass can be improved, and the energy and time required to melt the glass can be reduced. Thus, it can contribute to improving the productivity of the glass product and lowering the manufacturing cost.

Also preferably, in the alkali free glass according to the present invention, T _{4, which} is a temperature at a viscosity of 10 ⁴ dPas, may be less than 1250 ° C. More preferably, the alkali free glass according to the present invention may have a T ₄ of a temperature at a viscosity of 10 ⁴ dPas of less than 1240 ° C. According to this embodiment, since the T ₄ associated with the processing temperature of the glass is low, the processing of the glass can be facilitated, and energy and time required for processing the glass can be saved.

The display device according to the present invention may include the alkali-free glass described above. For example, the display device according to the present invention includes a glass substrate, but the glass substrate is an alkali-free glass substrate, expressed in terms of weight percent of oxide, SiO ₂ 61-73%, B ₂ O ₃ 0.5-3.9%, Al ₂ O ₃ 3.5 ~ 13.5%, MgO containing 9 ~ 13%, CaO 1 ~ 8%, SrO 4 ~ 10% , and does not substantially free of alkali metal oxide. Moreover, such an alkali free glass substrate may be substantially free of BaO, the density may be less than 2.55 g / cm ³ , and the coefficient of thermal expansion may be 3.0 to 4.5 [× 10 ⁻⁶ / K]. In addition, such an alkali free glass substrate may have a T ₂ of less than 1600 ° C and a T ₄ of less than 1250 ° C.

In particular, the display device according to the present invention is preferably a liquid crystal display (LCD) device. That is, a liquid crystal display device such as a TFT-LCD includes a glass substrate (panel), which may have the composition and physical properties described above. However, the display device according to the present invention may include various display devices such as a PDP device in addition to the LCD device.

Hereinafter, a method for producing the above-mentioned alkali free glass according to a preferred embodiment of the present invention will be described.

1 is a flowchart schematically showing a method for producing an alkali free glass according to an embodiment of the present invention.

Referring to Figure 1, first, the raw materials of the respective components contained in the glass are combined to be the target composition (S110). At this time, in the step S110, the alkali metal oxide component is substantially not included, SiO ₂ 61-73%, B ₂ O ₃ 0.5-3.9%, Al ₂ O ₃ 3.5-13.5 in terms of the oxide-based weight% display %, MgO is 9-13%, CaO is 1-8%, SrO 4-10% is combined so that the raw material components are combined. Preferably, in the step S110, SiO ₂ is 64 to 72%, B ₂ O ₃ is 1 to 3.9%, Al ₂ O ₃ is 4 to 12%, MgO is 9.5 to 12%, CaO is 4 to 8%, Combine the raw materials so that SrO is contained 4-8%. More preferably, the S110 step is SiO ₂ 66 ~ 71%, B ₂ O ₃ 3 ~ 3.9%, Al ₂ O ₃ 4 ~ 9%, MgO 10 ~ 11%, CaO 5 ~ 7.5% Combine the raw materials so that SrO is contained 4-6%. In addition, in the step S110, MgO + CaO + SrO may be combined with the raw material components to contain 15 to 26% by weight. More preferably, in step S110, the raw material components are combined to contain 17 to 24% by weight of MgO + CaO + SrO. Most preferably, the step S110, the raw material components are combined to contain 19 to 22% by weight of MgO + CaO + SrO.

On the other hand, it is good not to contain BaO substantially in such glass raw material components.

Next, the glass raw material thus combined is heated to a predetermined temperature, for example, 1500-1600 ° C. to melt the glass raw material (S120), and the molten glass is molded (S130). In this case, step S130 may be performed by a float method using a float bath, but the present invention is not necessarily limited to such a molding method. For example, the step S130, that is, the shaping of the glass may be performed by a down draw method or a fusion method.

As such, when the glass is molded in step S130, the molded glass is subjected to a slow cooling process is transferred to a slow cooling furnace (S140). The annealed glass is then cut to the desired size, and further processing such as polishing can be performed and made into a glass article through this series of processes.

As described above, the alkali-free glass produced by the glass manufacturing method according to an embodiment of the present invention, the density may be less than 2.55 g / cm ³ . And the thermal expansion coefficient of the produced alkali free glass may be 3.0-4.5 [* 10 <^-6> / K]. In addition, the alkali free glass produced as described above may have a T ₂ of less than 1600 ° C and a T ₄ of less than 1250 ° C. More preferably, the alkali free glass produced by the glass manufacturing method according to the present invention may have a T ₂ of less than 1550 ° C. and a T ₄ of less than 1240 ° C.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the embodiment according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Table 1 shows the glass composition and physical properties of the examples according to the present invention, Table 2 shows the glass composition and physical properties of the comparative example for comparison with these examples.

EXAMPLE

The raw material of each component was combined so that it might become a composition (weight-% basis) as shown in Table 1, and it heated and fuse | melted for 3 hours at the temperature of 1600 degreeC using the platinum crucible. At the time of melting, a platinum stirrer was inserted and stirred for 1 hour to homogenize the glass. Next, the molten glass was slowly cooled at 730 ° C to obtain the glass of each example. In addition, about the obtained glass, the composition was confirmed through the fluorescent X-ray analysis.

In addition, as physical properties for each Example glass, density, thermal expansion coefficient, T ₂ and T ₄ were measured by the following method, and the results are shown in Table 1.

(density)

About each Example glass, the density was measured using the Archimedes method.

(Coefficient of Thermal Expansion) (CTE)

About each Example glass, the average coefficent of thermal expansion was measured using the dilatometer.

(T ₂ )

For each example the glass, and measuring the viscosity by using a high-temperature viscometer to measure the temperature T ₂ at the time the viscosity to be 10 ² dPa · s. At this time, when the temperature is 1600 ℃ or more was calculated through the calculation from the Vogel-Fulcher-Tammann equation.

(T ₄ )

For each example of glass, using a high-temperature viscometer to measure the viscosity was measured the temperature T ₄ at the time the viscosity to be 10 ⁴ dPa · s.

Comparative example

The raw materials of each component were combined so as to have a composition (based on weight percent) as shown in Table 2, and heated and melted at a temperature of 1600 to 1800 ° C. for 3 hours using a platinum crucible. At the time of melting, a platinum stirrer was inserted and stirred for 1 hour to homogenize the glass. Subsequently, the molten glass was slowly cooled at 730 ° C to obtain the glass of each comparative example.

Further, as physical properties of each glass comparative examples, the above-described embodiment and measuring the density, the thermal expansion coefficient, T ₂ and T ₄ in the same way, the results are shown in Table 2.

Table 1

TABLE 2

As shown in Table 1 and Table 2, for the glass in Examples (Examples 1 to 10), the density was less than 2.55 g / cm ³ , and the average thermal expansion coefficient (CTE) was 3.0 to 4.5 (× 10 ⁻⁶ / K) was confirmed. In the case of the embodiment of the glass, T ₂ is less than 1600 ℃ and T ₄ have been confirmed to be less than 1250 ℃.

On the other hand, in Comparative Examples (Comparative Examples 1 to 11), was determined to be a high density, the average coefficient of thermal expansion, T ₂ and / or T _4, compared with the embodiment for the glass.

Therefore, it can be seen from the comparative results of these examples and the comparative example that, according to the present invention, it is possible to obtain glass having excellent properties, particularly glass having excellent properties as a substrate glass for display. In addition, the glass according to the present invention has a low T ₂ and T ₄ is excellent in the meltability of the glass and can be easily processed, as well as energy and time required during the processing or melting process can be reduced. Able to know.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (20)

1. In terms of weight percent oxide,

   SiO ₂ 61-73%;

   B ₂ O ₃ 0.5-3.9%;

   Al ₂ O ₃ 3.5-13.5%;

   MgO 9-13%;

   CaO 1-8%; And

   SrO 4 ~ 10%

   And an alkali metal oxide substantially free of alkali free glass.
2. The method of claim 1,

   Alkali-free glass, which is substantially free of BaO.
3. The method of claim 1,

   In terms of weight percent oxide,

   SiO ₂ 64-72%;

   B ₂ O ₃ 1-3.9%;

   Al ₂ O ₃ 4-12%;

   MgO 9.5-12%;

   CaO 4-8%; And

   SrO 4 ~ 8%

   An alkali free glass comprising a.
4. The method of claim 1,

   In terms of weight percent oxide,

   MgO + CaO + SrO 15 ~ 26%

   An alkali free glass comprising a.
5. The method of claim 1,

   In terms of weight percent oxide,

   MgO + CaO + SrO 17 ~ 24%

   An alkali free glass comprising a.
6. The method of claim 1,

   In terms of weight percent oxide,

   SiO ₂ + Al ₂ O ₃ 72 ~ 79%

   An alkali free glass comprising a.
7. The method of claim 1,

   An alkali free glass having a density of less than 2.55 g / cm ³ and a coefficient of thermal expansion of 3.0 × 10 ⁻⁶ / K to 4.5 × 10 ⁻⁶ / K.
8. The method of claim 1,

   An alkali free glass, wherein the temperature at a viscosity of 10 ² dPas is less than 1600 ° C and the temperature at a viscosity of 10 ⁴ dPas is less than 1250 ° C.
9. The method of claim 1,

   The alkali free glass characterized by the temperature in viscosity 10 ² dPas being less than 1550 degreeC, and the temperature in viscosity 10 ⁴ dPas being less than 1240 degreeC.
10. A display device comprising the alkali free glass according to any one of claims 1 to 9.
11. The method of claim 10,

    And the display device is a liquid crystal display device.
12. In terms of weight percent oxide,

    SiO ₂ 61-73%;

    B ₂ O ₃ 0.5-3.9%;

    Al ₂ O ₃ 3.5-13.5%;

    MgO 9-13%;

    CaO 1-8%; And

    SrO 4 ~ 10%

    And a step of combining the glass raw materials so as to contain substantially no alkali metal oxides.
13. The method of claim 12,

    The glass raw material combining step is a method for producing an alkali-free glass, characterized in that it contains substantially no BaO.
14. The method of claim 12,

    The glass raw material combination step,

    In terms of weight percent oxide,

    SiO ₂ 64-72%;

    B ₂ O ₃ 1-3.9%;

    Al ₂ O ₃ 4-12%;

    MgO 9.5-12%;

    CaO 4-8%; And

    SrO 4 ~ 8%

    An alkali free glass production method characterized by containing a.
15. The method of claim 12,

    The glass raw material combination step,

    In terms of weight percent oxide,

    MgO + CaO + SrO 15 ~ 26%

    An alkali free glass production method characterized by containing a.
16. The method of claim 12,

    The glass raw material combination step,

    In terms of weight percent oxide,

    MgO + CaO + SrO 17 ~ 24%

    An alkali free glass production method characterized by containing a.
17. The method of claim 12,

    The glass raw material combination step,

    In terms of weight percent oxide,

    SiO ₂ + Al ₂ O ₃ 72 ~ 79%

    An alkali free glass production method characterized by containing a.
18. The method of claim 12,

    The density of the produced glass is less than 2.55 g / cm ³ , the thermal expansion coefficient of the produced glass is 3.0 × 10 ^-6 / K ~ 4.5 × 10 ^-6 / K characterized in that the alkali-free glass production method.
19. The method of claim 12,

    The temperature at viscosity 10 ² dPas of the produced glass is less than 1600 ° C, and the temperature at viscosity 10 ⁴ dPas of the produced glass is less than 1250 ° C.
20. The method of claim 12,

    A method for producing an alkali free glass, wherein the temperature at the viscosity 10 ² dPas of the produced glass is less than 1550 ° C., and the temperature at the viscosity 10 ⁴ dPas of the glass is less than 1240 ° C.

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