KR102297729B1 - Glass production method and glass - Google Patents

Abstract

In a method for manufacturing a glass, or more water vapor pressure atmosphere are 1hPa, the content of the glass composition of _{Li 2 O + Na 2 O +} K 2 O is subjected to heat treatment the glass is less than 5% by mass.

Description

Glass manufacturing method and glass

The present invention relates to a method for manufacturing glass and glass, and more specifically, to a glass substrate for flat panel displays such as liquid crystal displays and organic EL displays, touch panel displays, chip size packages (CSPs), charge coupled devices (CCDs), equal magnifications It is related with the manufacturing method of glass suitable for cover glass, such as a proximity type solid-state image sensor (CIS), and glass.

Flat panel displays, such as a liquid crystal display and an organic electroluminescent display, are calculated|required further thinning and enlargement, and the glass substrate for flat panel displays is also calculated|required further thinning and enlarged by this.

Alkali-free glass is generally used for the glass substrate of this use.

J. Am. Ceram. Soc., 69, p. 815-821, 1986

When a glass substrate becomes thin and enlarges, it will become easy to generate|occur|produce damage. For this reason, the trial of strength improvement becomes important.

As a method of increasing the strength of glass, a method of forming a compressive stress layer on the surface by ion exchange (ion exchange treatment) of alkali ions, that is, a chemical strengthening method is known, and this chemically strengthened glass is already used as a cover glass of a touch panel display. has been put into practice.

However, since alkali-free glass does not contain an alkali metal oxide in a glass composition, it is difficult to apply an ion exchange treatment.

Further, as a method of increasing the strength of glass, a method of forming a compressive stress layer on the surface by blowing low-temperature air into high-temperature glass, that is, a physical strengthening treatment is known.

However, since the glass substrate for flat panel displays has a small plate|board thickness, it is difficult to apply a physical strengthening process.

This invention takes the said situation into consideration, and the technical subject is to invent the method which can raise the intensity|strength of thin low-alkali glass or alkali free glass appropriately.

As a result of repeating various experiments, this inventor discovers that the said technical subject can be solved by heat-processing glass in the atmosphere with high water vapor pressure, and proposes it as this invention. That it is, in the manufacturing method of the glass of the present invention is not less than a water vapor pressure atmosphere are 1hPa, characterized in that the content of the glass composition of _{Li 2 O + Na 2 O +} K 2 O heat treatment the glass is less than 5% by weight. Here, _{"Li 2 O + Na 2 O +} K 2 O " refers to the total amount of Li ₂ O, Na ₂ O and K ₂ O. In addition, the "heat treatment" as used in this invention includes not only the independent heat processing process, but the slow cooling process at the time of shaping|molding, for example.

When glass is heat-treated in an atmosphere with high water vapor pressure, the time constant of relaxation becomes small and stress relaxation advances, but this stress relaxation advances faster on the glass surface side than inside the glass under the influence of the atmosphere. Thereby, after heat treatment, the inner side of the glass shrinks from the glass surface, and a compressive stress layer is formed on the glass surface. As a result, it becomes possible to raise the intensity|strength of thin low alkali glass or alkali free glass appropriately.

Second, in the manufacturing method of the glass of the present invention, it is preferable that the heat treatment temperature is 150°C or higher. The higher the heat treatment temperature, the easier it is for stress relaxation to occur.

Third, in the manufacturing method of the glass of the present invention, it is preferable to heat-treat at the time of molding, particularly, to introduce an atmosphere having a high water vapor pressure when performing the slow cooling step at the time of molding. Thereby, a separate heat treatment process becomes unnecessary, and the manufacturing efficiency of glass improves.

Fourth, in the manufacturing method of the glass of this invention, it is preferable to heat-process at the time of shaping|molding by an overflow down-draw method. Thereby, it becomes possible to expose both surfaces of a glass ribbon to the atmosphere with high water vapor pressure, and it becomes easy to raise the intensity|strength of both surfaces of glass. Here, in the "overflow down-draw method", the molten glass overflows from both sides of a trough-shaped molded body having heat resistance, and the overflowed molten glass is merged at the lower end of the trough-shaped molded body, and while flowing downward, forming a glass substrate is produced. way to do it

Fifth, in the method for manufacturing glass of the present invention, it is preferable to heat-treat after molding, particularly, to heat-treat the glass after molding using a heat treatment furnace. This makes it easier to control the relaxation phenomenon.

Sixth, in the manufacturing method of the glass of the present invention, it is preferable to heat-treat in a state in which a load stress is applied to the glass. When heat treatment is performed in a state in which tensile stress is applied to glass by an external load, stress relaxation on the surface of the glass advances and the tensile stress decreases, but on the other hand, stress relaxation inside the glass does not proceed sufficiently. For this reason, when the load stress is removed after heat processing, only the inside of glass will be in a state in which it shrink|contracts, and a compressive stress can be provided efficiently to the glass surface.

Seventh, in the manufacturing method of the glass of the present invention, the glass is SiO ₂ 50-80% _{by mass% as a glass composition, Al 2} O ₃ 5-25%, B ₂ O ₃ 0-20%, Li ₂ O+Na O + K ₂ O less than ₂ 0 to 5%, preferably contains MgO + CaO + SrO + BaO 1~25 %. Here, "MgO+CaO+SrO+BaO" refers to the total amount of MgO, CaO, SrO, and BaO.

Eighth, in the glass of the present invention, _{the content of Li 2} O+Na ₂ O+K ₂ O in the glass composition is less than 5% by mass, and the proton concentration at the position where the depth from the outermost surface is 1 μm is the outermost surface. It is characterized in that it is higher than the proton concentration at a position with a depth of 10 μm. As described above, when glass is heat treated in an atmosphere with high water vapor pressure, a compressive stress layer is formed on the surface of the glass, but in this case, the proton concentration on the glass surface becomes higher than the proton concentration inside the glass. Therefore, if the proton concentration at a position having a depth of 1 μm from the outermost surface and the proton concentration at a position having a depth of 10 μm from the outermost surface are compared, the difference between the stress relaxation between the glass surface and the inside of the glass is appropriately evaluated. thing becomes possible Here, the "proton concentration" can be measured by a glow discharge emission spectrometry (GD-OES) or the like.

Ninth, the glass of the present invention preferably has (proton concentration at a position having a depth of 1 µm from the outermost surface)/(proton concentration at a position having a depth of 10 µm from the outermost surface) of 1.1 or more.

Tenth, it is preferable that the glass of this invention is flat plate shape and plate thickness is 0.5 mm or less.

Eleventh, the glass of the present invention is SiO ₂ 50 to 80%, Al ₂ O _{3 5 to} 25%, B ₂ O ₃ 0 to 20%, Li ₂ O+Na ₂ O+K _{2 in mass% as a glass composition} It is preferable to contain less than 0-5% of O and 1-25% of MgO+CaO+SrO+BaO. In this way, it becomes easy to apply to the glass substrate for flat panel displays.

Twelfth, it is preferable that the glass of this invention is shape|molded by the overflow down-draw method.

Thirteenth, it is preferable that the glass of the present invention is not subjected to ion exchange treatment. In this way, the manufacturing cost of glass can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view for illustrating the manufacturing method of the glass which concerns on embodiment of this invention.
2 is a perspective view for explaining an experiment of [Example 2].

In the glass manufacturing method of the present invention, the glass is heat treated in an atmosphere having a water vapor pressure of 1 hPa or more, but the water vapor pressure is preferably 5 hPa or more, 10 hPa or more, 20 hPa or more, 50 hPa or more, 100 hPa or more, or 200 hPa or more, particularly preferably 300 to 2000 hPa. . When the water vapor pressure is low, stress relaxation becomes difficult to advance. In addition, if the temperature of the steam generator is increased, the steam pressure can be increased.

The heat treatment temperature is preferably 150°C or higher, 200°C or higher, 300°C or higher, 400°C or higher or 500°C or higher, particularly preferably 600°C or higher. When the heat treatment temperature is low, stress relaxation becomes difficult to proceed. On the other hand, when the heat treatment temperature is too high, the difference in stress relaxation between the glass surface and the inside of the glass becomes small, so that it becomes difficult to increase the strength of the glass. Therefore, the heat treatment temperature is preferably 900°C or less.

The heat treatment time is preferably 1 minute or more, 2 minutes or more, 3 minutes or more, 5 minutes or more, 10 minutes or more, or 30 minutes or more, particularly preferably 60 minutes or more. When the heat treatment time is short, it becomes difficult for stress relaxation to proceed. On the other hand, when the heat treatment time is too long, the manufacturing cost of the glass rises. Accordingly, the heat treatment time is preferably 15 hours or less, particularly preferably less than 2 hours. In addition, the heat treatment time in the case of heat-processing glass at the time of shaping|molding refers to the time for glass to stay in the temperature range of 150 degreeC or more in an atmosphere with a water vapor pressure of 1 hPa or more.

In the method for producing the glass of the present invention, it is preferable to heat treatment in a state in which a load stress is applied, and the load stress is preferably 0.1 MPa or more, 0.2 MPa or more, 0.5 MPa or more, 1 MPa or more, 5 MPa or more, 10 MPa or more, 20 MPa or more, or 50 MPa or more, particularly preferably 100 MPa or more. The higher the load stress, the easier the stress relaxation will proceed. However, when the load stress is too high, the glass tends to break during heat treatment. Therefore, the load stress is preferably 1000 MPa or less.

Although various methods are assumed as a means for applying a load stress to glass, among them, the method of bending or bending glass from a viewpoint of manufacturing efficiency is preferable, and especially the method of bending or bending glass at the time of shaping|molding is preferable.

In the manufacturing method of the glass of this invention, it is preferable to heat-process at the time of shaping|molding (at the time of execution of a slow cooling process) from a viewpoint of manufacturing efficiency, and it is also preferable to heat-process after shaping|molding from a viewpoint of controlling a relaxation phenomenon. In addition, it is preferable to use an electric furnace etc. for heat processing after shaping|molding.

In the glass of the present invention, _{the content of Li 2} O+Na ₂ O+K ₂ O in the glass composition is less than 5% by mass, and the proton concentration at the position where the depth from the outermost surface is 1 μm is the depth from the outermost surface. It is characterized in that it is higher than the proton concentration at a position of 10 μm. Similarly, in the glass of the present invention, _{the content of Li 2} O+Na ₂ O+K ₂ O in the glass composition is less than 5% by mass, and the proton concentration at a position where the depth from the outermost surface is 0.2 μm is from the outermost surface. It is preferable that the depth of is higher than the proton concentration at a position of 10 μm. In addition, although the technical characteristics of the glass of the present invention overlap with the technical characteristics of the manufacturing method of the glass of the present invention (the technical characteristics of the manufacturing method of the glass of the present invention overlap with the technical characteristics of the glass of the present invention), in this specification For convenience, a detailed description of the overlapping portion is omitted.

In the glass of the present invention, a glass batch prepared so as to have a predetermined glass composition is put into a continuous glass melting kiln, the glass batch is heated and melted, the obtained molten glass is clarified, and then supplied to a forming apparatus, and then flat plate shape It can be manufactured by shaping|molding with etc. In addition, as described above, when the glass is heat-treated in an atmosphere with high water vapor pressure during and/or after molding, the proton concentration on the outermost surface can be increased.

It is preferable that the glass of this invention is shape|molded by the overflow down-draw method. In the case of the overflow down-draw method, since the surface which should become the surface of a glass substrate is shape|molded in the state of a free surface without contacting a gutter-shaped refractory body, the surface quality of a glass substrate can be raised. As a result, a glass substrate with good surface quality can be obtained by unpolishing.

The glass of this invention can employ|adopt various shaping|molding methods other than the overflow down-draw method. For example, a molding method such as a slot-down method, a float method, or a roll-out method can be adopted.

In the glass of the present invention, the content of the glass composition of Li ₂ O + Na ₂ O + K ₂ O is preferably less than 5% by mass, 3% or less, 2% or less, 1% or less, 0.5 mass% or less or 0.3 mass% or less, particularly preferably 0.1 mass% or less. Each content of Li ₂ O, Na ₂ O and K ₂ O in the glass composition is also preferably less than 5 mass %, 3 mass % or less, 2 mass % or less, 1 mass % or less, 0.5 mass % or less, or 0.3 mass %. Below, especially preferably, it is 0.1 mass % or less. As described above, when the content of the alkali metal oxide decreases, it becomes difficult to apply the ion exchange treatment, but the strength improvement effect of the present invention becomes relatively large. Moreover, when content of an alkali metal oxide decreases, heat resistance, weather resistance, etc. will become easy to improve. Moreover, stress relaxation in an atmosphere with high water vapor pressure hardly affects a glass composition, and it advances suitably also in a low alkali glass or an alkali free glass.

In the glass of the present invention, (proton concentration at a position having a depth of 1 µm from the outermost surface)/(proton concentration at a position having a depth of 10 µm from the outermost surface) is preferably 1.1 or more, 1.15 or more, 1.2 or greater or 1.25 or greater. When (proton concentration at a position with a depth of 1 µm from the outermost surface)/(proton concentration at a position with a depth of 10 µm from the outermost surface) decreases, the difference in stress relaxation between the surface of the glass and the inside of the glass becomes smaller. , it becomes difficult to increase the strength of the glass.

(Proton concentration at a position having a depth of 0.2 µm from the outermost surface)/(Proton concentration at a position having a depth of 10 µm from the outermost surface) is preferably 1.1 or more, 1.15 or more, 1.2 or more, 1.25 or more, or 1.3 or more, particularly preferably 1.5 or more. When (proton concentration at a position with a depth of 0.2 µm from the outermost surface)/(proton concentration at a position with a depth of 10 µm from the outermost surface) decreases, the difference in stress relaxation between the surface of the glass and the inside of the glass becomes smaller. , it becomes difficult to increase the strength of the glass.

(Proton concentration at a position having a depth of 0.02 µm from the outermost surface)/(Proton concentration at a position having a depth of 10 µm from the outermost surface) is preferably 1.2 or more, 1.25 or more, 1.3 or more, 1.5 or more, or 2.0 or more, particularly preferably 2.5 or more. When (proton concentration at a position with a depth of 0.02 µm from the outermost surface)/(proton concentration at a position with a depth of 10 µm from the outermost surface) decreases, the difference in stress relaxation between the surface of the glass and the inside of the glass becomes smaller. , it becomes difficult to increase the strength of the glass.

It is preferable that the glass of this invention makes a flat plate shape, ie, it is a glass substrate. If it is flat panel shape, it will become easy to apply to the glass substrate for flat panel displays, a cover glass, etc. The plate thickness is preferably 0.5 mm or less, 0.4 mm or less, or 0.3 mm or less, and particularly preferably 0.05 to 0.2 mm. The smaller the plate thickness, the more difficult it is to apply the physical strengthening treatment, but the strength improvement effect of the present invention is relatively large. Moreover, when plate|board thickness is small, it will become easy to curve glass, and it will become easy to apply load stress to glass. Furthermore, when plate|board thickness is small, it will become easy to lighten a glass substrate, and it will become easy to lighten a device also. In addition, stress relaxation in an atmosphere with a high water vapor pressure has little effect on the plate thickness, and proceeds appropriately even when the plate thickness is small.

The glass of the present invention has a glass composition, in terms of mass%, SiO ₂ 50 to 80%, Al ₂ O _{3 5 to} 25%, B ₂ O ₃ 0 to 20%, Li ₂ O+Na ₂ O+K ₂ O 0 to It is preferable to contain less than 5% and 1-25% of MgO+CaO+SrO+BaO. The reason for limiting the glass composition as mentioned above is shown below. In addition, in description of the content range of each component, % indication points out mass %.

SiO ₂ is a component forming the skeleton of glass. The content of SiO ₂ is preferably 50 to 80%, 54 to 70% or 56 to 66%, particularly preferably 58 to 64%. When the content of SiO ₂ is too small, and the density is excessively increased Further, the acid resistance is likely to decrease. On the other hand, when the content of SiO ₂ is too much, the high temperature viscosity becomes high the melting properties in addition to being easy to degrade, so liable to devitrification, such as determining the precipitation of cristobalite, is likely to have a liquid temperature rise.

Al ₂ O ₃ is a component forming the skeleton of glass, is also a component of suppressing the distortion component and the height of a point or Young's modulus, more phase separation (分相). The content of Al ₂ O ₃ is preferably 5 to 25%, 12 to 24% or 15 to 22%, particularly preferably 16 to 21%. When the content of Al ₂ O ₃ is too small, the distortion point, and the Young's modulus is apt to become degraded, and is apt to have a glass phase separation. On the other hand, when the content of Al ₂ O ₃ is too large, the devitrification crystal such as mullite or chairman seat is so liable to be precipitated, the liquid is liable to temperature rise.

B ₂ O ₃ is a component to increase the melting property, resistance to devitrification, and scratch resistance. The content of B ₂ O ₃ is preferably 0 to 20%, 0.1 to 12%, 1 to 10%, or 3 to 9%, particularly preferably 5 to 8%. When the content of B ₂ O ₃ is too small, it becomes easy to decrease teeming molten or substantial, and tends to resistance to chemical degradation of the hydrofluoric acid-based. On the other hand, when the content of B ₂ O ₃ is too large, it is easy to decrease the Young's modulus or the distortion point.

The contents of Li ₂ O, Na ₂ O, and K ₂ O are as described above.

Alkaline earth metal oxide is a component that lowers high-temperature viscosity and improves meltability. The content of MgO+CaO+SrO+BaO is preferably 1 to 25%, 3 to 20%, or 5 to 15%, particularly preferably 7 to 13%. When there is too little content of MgO+CaO+SrO+BaO, meltability will fall easily. On the other hand, when there is too much content of MgO+CaO+SrO+BaO, glass will become easy to devitrify.

MgO is a component that lowers high-temperature viscosity and improves meltability, and among alkaline earth metal oxides, it is a component that significantly increases Young's modulus. The content of MgO is preferably 0 to 15%, 0 to 8%, 0 to 7%, 0 to 6% or 0 to 3%, particularly preferably 0.1 to 2%. When there is too little content of MgO, meltability and Young's modulus will fall easily. On the other hand, when there is too much content of MgO, while devitrification resistance will fall easily, a strain point will fall easily.

CaO is a component that does not lower the strain point, lowers the high-temperature viscosity, and remarkably improves the meltability. In addition, in alkaline earth metal oxides, since the raw material to be introduced is relatively inexpensive, it is a component that reduces the cost of the raw material. The content of CaO is preferably 1 to 15%, 3 to 11% or 4 to 10%, particularly preferably 5 to 9%. When there is too little content of CaO, it will become difficult to enjoy the said effect. On the other hand, when there is too much content of CaO, while glass will become devitrified easily, a thermal expansion coefficient will become high easily.

SrO is a component which suppresses a powder phase and improves devitrification resistance. Moreover, while not reducing a strain point, while being a component which reduces high temperature viscosity and improves meltability, it is a component which suppresses a raise of liquidus temperature. The content of SrO is preferably 0 to 15% or 0.1 to 9%, particularly preferably 0.5 to 6%. When there is too little content of SrO, it will become difficult to enjoy the said effect. On the other hand, when there is too much content of SrO, the devitrification crystal of a strontium silicate system will precipitate easily, and devitrification resistance will fall easily.

BaO is a component which improves devitrification resistance remarkably. The content of BaO is preferably 0 to 15%, 0 to 12% or 0.1 to 9%, particularly preferably 1 to 7%. When there is too little content of BaO, it will become difficult to enjoy the said effect. On the other hand, when there is too much content of BaO, while a density will become high too much, meltability will fall easily. Moreover, it becomes easy to precipitate the devitrification crystal containing BaO, and it becomes easy to raise liquidus temperature.

In addition to the above components, for example, the following components may be added. Further, the content of the components other than the above components is preferably 10% or less in total, particularly preferably 5% or less, from the viewpoint of accurately enjoying the effects of the present invention.

ZrO ₂ has a function of increasing the strain point and Young's modulus. However, when the content of ZrO ₂ is too large, substantial teeming is significantly reduced. In particular, the case of adding SnO _2, it is preferable to strictly regulate the content of ZrO _2. The content of ZrO ₂ is preferably 0.4% or less or 0.3% or less, particularly preferably 0.01 to 0.2%.

SnO ₂ is a component having a good clarification action in a high temperature region. The content of SnO ₂ is preferably 0-1%, 0.01-0.5% or 0.05-0.3%, particularly preferably 0.1-0.3%. If the content of SnO ₂ is too much, devitrification crystals of SnO ₂ is likely to be precipitated into the glass.

As described above, in the glass of the present invention, _{the addition of SnO 2 as a clarifier is suitable, but CeO 2} , SO ₃ , C, metal powder (eg Al, Si, etc.) as a clarifier as long as the glass properties are not impaired. may be added up to 1%.

As ₂ O ₃ , Sb ₂ O ₃ , F and Cl also act effectively as clarifiers, and the glass of the present invention does not exclude the content of these components, but from an environmental point of view, the contents of these components are each less than 0.1%. , particularly preferably less than 0.05%.

Example One

Hereinafter, the present invention will be described in detail based on Examples. In addition, the following examples are mere examples. The present invention is not limited at all to the following examples.

First, as a glass composition, in terms of mass%, SiO ₂ 60%, Al ₂ O ₃ 16.5%, B ₂ O ₃ 10%, MgO 0.5%, CaO 8%, SrO 4%, BaO 0.7%, ZrO ₂ 0.1%, SnO ₂ A glass batch was produced by combining various glass raw materials so that 0.2% might be contained. Next, the obtained glass batch is put into a continuous melting furnace, melted at 1500 to 1600° C., then the molten glass is clarified and stirred, then supplied to a forming apparatus, and a flat plate having a plate thickness of 0.4 mm by an overflow down-draw method molded into shape. Then, it cut|disconnected to predetermined size and obtained the glass substrate. At the time of shaping|molding, water vapor|steam was supplied into the shaping|molding apparatus so that the water vapor pressure of the surface vicinity of a glass ribbon might become 500 hPa. EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail, referring FIG.

1 is a side view for illustrating a method of manufacturing a glass according to an embodiment of the present invention. The molding apparatus 1 includes a trough-shaped molded body 3 for molding a glass ribbon 2, a roller R1, a roller R2, a glass ribbon 2 and a trough-shaped molded body 3 surrounding the The peripheral wall 4 and the roller 5 for supporting and conveying the glass ribbon 2 are made into main components.

The trough-shaped molded object 3 is shape|molded, descending the glass ribbon 2 from the lower end. Below the molded object 3, a set of roller R1 which contacts the glass ribbon 2 from both surfaces is provided. Moreover, also about any surface side of the glass ribbon 2, a pair of roller R1 contacts only the width direction both ends of the glass ribbon 2. The roller R1 has a function to regulate the shrinkage in the width direction while cooling the glass ribbon 2 .

Under roller R1, a plurality of sets (five sets in this embodiment) are provided along the up-down direction of one set of roller R2 which contact|abuts to the glass ribbon 2 from both surfaces. In addition, a pair of roller R2 contacts only the width direction both ends of the glass ribbon 2 also about any surface side of the glass ribbon 2 . The roller R2 has a function of extending|stretching the glass ribbon 2 downward.

The peripheral wall 4 surrounds the roller R1 , the roller R2 , the glass ribbon 2 , and the trough-shaped molded body 3 . The peripheral wall 4 has an opening 6 at its lower end, through which the glass ribbon 2 exits to the outside space. The peripheral wall 4 does not have an opening part with respect to the external space substantially other than the opening part 6, For example, it has the heat-retaining function of the trough-shaped molded object 3, and the slow cooling function of the glass ribbon 2. As shown in FIG.

The inner space around the lower end of the peripheral wall 4 is divided into a first space S1 and a second space S2 by a glass ribbon 2 descending from the trough-shaped molded body 3 and a separating wall 9, , these are the heat treatment spaces. Water vapor is supplied to the first space S1 and the second space S2 through the supply passages 7 and 8 . And the temperature of 1st space S1 and 2nd space S2 is 300-600 degreeC. Time for which the glass ribbon 2 passes through 1st space S1 and 2nd space S2 is 1 minute.

Although not shown in the present embodiment, temperature difference imparting means for adjusting the respective temperatures of the first space S1 and the second space S2 and imparting a temperature difference between these spaces S1 and S2 is provided. . By this temperature difference provision means, a temperature difference is provided so that the temperature of 1st space S1 may become higher than 2nd space S2. This temperature difference application acts to bend the glass ribbon 2 . In addition, by changing to this temperature difference provision, you may change the position of the roller 5 etc. (for example, the position of the left-right direction of the roller 5), and you may make the glass ribbon 2 curve.

About the obtained glass substrate, the crack generation|occurrence|production condition was evaluated. Specifically, first, in a thermo-hygrostat maintained at 30% humidity and 25 ° C., a quadrangular pyramid indenter set at a predetermined load is driven into the glass surface for 15 seconds, and cracks generated from the 4 corners of the indentation after 15 seconds. Count the number (maximum of 4 for one indentation). In this way, the quadrangular pyramid indenter was press-fitted 20 times, and the total number of cracks 20 seconds after the press-in was calculated, and then the total number of cracks/80×100 (%) was calculated. In addition, the Vickers hardness tester was manufactured by Matsuzawa Co., Ltd. It was set as MX-50 of the product, the material of the quadrangular pyramid indenter was made into diamond, the facing angle of the quadrangular pyramid indenter was 130 degrees, and the indentation load was 100 gf.

As a result, as mentioned above, the total number of cracks of the glass substrate which supplied water vapor|steam in the shaping|molding apparatus was 20 pieces. Moreover, it was 43 when the total number of cracks of a glass substrate was evaluated similarly about the case where the inside of a shaping|molding apparatus was further controlled in the atmosphere used as less than 1 hPa without supplying water vapor|steam in a shaping|molding apparatus.

Example 2

First, as a glass composition, in terms of mass%, SiO ₂ 60%, Al ₂ O ₃ 16.5%, B ₂ O ₃ 10%, MgO 0.5%, CaO 8%, SrO 4%, BaO 0.7%, ZrO ₂ 0.1%, SnO ₂ A glass batch was produced by combining various glass raw materials so as to contain 0.2%. Next, the obtained glass batch is put into a continuous melting furnace, melted at 1500 to 1600° C., then the molten glass is clarified and stirred, then supplied to a molding apparatus, and is formed into a film with a thickness of 0.1 mm by an overflow downdraw method. It shape|molded and it cut|disconnected into the elongate rectangular shape of 300 mm x 35 mm.

In addition, as shown in FIG. 2 , after bending or curving and arranging the elongated rectangular glass film 10 on a heat treatment jig having a pair of parallel plates 11 , the water vapor pressure in the furnace was controlled to 5 hPa. It was put into an electric furnace and heat-treated at 200°C for 10 hours. Here, the space|interval of a pair of parallel plates 11 was made into 6 mm. Moreover, with respect to the convex-shaped front-end|tip 10a of the glass film 10, the glass film 10 was bent so that the tensile stress calculated by following formula 1 might be set to 1.4 GPa. Here, σ is the tensile stress in the long axis direction, that is, the long side direction (GPa), t is the plate thickness of the glass film 10 (mm), D is the spacing between the pair of parallel plates 11 (mm), E is It is the Young's modulus (GPa) of the glass film 10 (refer nonpatent literature 1).

About the glass film after heat processing, the crack generation|occurrence|production condition was evaluated. Specifically, first, in a thermo-hygrostat maintained at a humidity of 30% and a temperature of 25°C, a quadrangular pyramid indenter set to a predetermined load is driven into the glass surface for 15 seconds, and cracks generated from the 4 corners of the indentation after 15 seconds Count the number (maximum of 4 for one indentation). In this way, the quadrangular pyramid indenter was press-fitted 20 times, and the total number of cracks 20 seconds after the press-in was calculated, and then the total number of cracks/80×100 (%) was calculated. In addition, the Vickers hardness tester was manufactured by Matsuzawa Co., Ltd. It was set as MX-50 of the product, the material of the quadrangular pyramid indenter was made into diamond, the facing angle of the quadrangular pyramid indenter was 130 degrees, and the indentation load was 100 gf.

As a result, there were 32 cracks in the major axis direction (long side direction) and 14 cracks in the minor axis direction (short side direction). The reason why there are few cracks in the minor axis direction (short side direction) is because the tensile stress of the major axis direction (long side direction) in the convex front-end|tip of a glass film turned into compressive stress by heat processing.

Moreover, when the same evaluation was performed about the elongate rectangular glass film which is not heat-processed, there were 23 cracks in the uniaxial direction.

Moreover, about the glass film which performed the said heat processing, the proton concentration ratio was computed from the light emission intensity ratio of the proton in the depth direction using GD-OES (HORIBA, Ltd. GD-Profiler2). The measurement conditions of GD-OES were discharge power: 80 W, and discharge pressure: 200 Pa. In addition, the proton emission intensity ratio is equal to the proton concentration ratio. (Proton concentration at a position with a depth of 0.02 µm from the outermost surface)/(Proton concentration at a position with a depth of 10 µm from the outermost surface) is 2.6, (at a position with a depth of 0.2 µm from the outermost surface) Proton concentration)/(proton concentration at a position with a depth of 10 µm from the outermost surface) is 1.3, and (proton concentration at a position with a depth of 1 µm from the outermost surface)/(a depth of 10 µm from the outermost surface) is The proton concentration at the phosphorus position) was 1.1.

Experiments in [Example 1] and [Example 2] can be similarly performed with the materials (sample Nos. A to I) shown in Table 1, and the effect of suppressing crack generation can be similarly enjoyed.

1: Forming device 2: Glass ribbon
3: Gutter-shaped molded body 4: Peripheral wall
5, R1, R2: Roller 6: Opening
7, 8: supply port S1: first space
S2: second space

Claims (13)

_{SiO 2} 50-80%, Al ₂ O ₃ 5-25%, B ₂ O ₃ 0-20%, Li ₂ O+Na ₂ O+K ₂ O 0-0.5%, MgO+CaO in mass% as glass composition A method for producing glass, wherein a glass containing 1 to 25% of +SrO+BaO is heat-treated in an atmosphere having a water vapor pressure of 1 hPa or more in a slow cooling step during molding. The method of claim 1,
Method for producing glass, characterized in that the heat treatment temperature is 150 ℃ or more. delete 3. The method according to claim 1 or 2,
A method for manufacturing glass, characterized in that heat treatment is performed during molding by an overflow down-draw method. 3. The method according to claim 1 or 2,
A method for producing glass, characterized in that heat treatment is further performed after molding. 3. The method according to claim 1 or 2,
A method for manufacturing glass, characterized in that heat treatment is performed in a state in which a load stress is applied to the glass. delete delete delete delete delete delete delete

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