WO2013172307A1 - Method for producing plate glass - Google Patents

Method for producing plate glass Download PDF

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Publication number
WO2013172307A1
WO2013172307A1 PCT/JP2013/063309 JP2013063309W WO2013172307A1 WO 2013172307 A1 WO2013172307 A1 WO 2013172307A1 JP 2013063309 W JP2013063309 W JP 2013063309W WO 2013172307 A1 WO2013172307 A1 WO 2013172307A1
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WIPO (PCT)
Prior art keywords
glass
mgo
cao
sro
less
Prior art date
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PCT/JP2013/063309
Other languages
French (fr)
Japanese (ja)
Inventor
史朗 谷井
博文 徳永
知之 ▲辻▼村
学 西沢
小池　章夫
Original Assignee
旭硝子株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 旭硝子株式会社 filed Critical 旭硝子株式会社
Priority to CN201380024855.1A priority Critical patent/CN104302590B/en
Priority to KR1020147022619A priority patent/KR101974681B1/en
Priority to JP2014515617A priority patent/JPWO2013172307A1/en
Publication of WO2013172307A1 publication Critical patent/WO2013172307A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/22—Surface treatment of glass, not in the form of fibres or filaments, by coating with other inorganic material
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C03B25/06—Annealing glass products in a continuous way with horizontal displacement of the glass products
    • C03B25/08—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C1/00—Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • C03C3/093—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium containing zinc or zirconium
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Definitions

  • the present invention relates to a method for producing a plate glass made of non-alkali glass, which is suitable as a substrate glass for various displays and a substrate glass for a photomask.
  • non alkali means that the content of alkali metal oxides (Li 2 O, Na 2 O, K 2 O) is 2000 mol ppm or less.
  • the following characteristics have been required for various display substrate glasses, particularly those in which a metal or oxide thin film is formed on the surface.
  • alkali metal oxide When an alkali metal oxide is contained, alkali metal ions diffuse into the thin film and deteriorate the film characteristics. Therefore, the content of the alkali metal oxide is extremely low. The oxide content is 2000 mol ppm or less.
  • the strain point When exposed to a high temperature in the thin film forming process, the strain point is high so that the deformation (thermal shrinkage) associated with glass deformation and glass structural stabilization can be minimized.
  • a-Si amorphous silicon
  • p-Si polycrystalline silicon
  • a glass having a small average thermal expansion coefficient is required to increase productivity and thermal shock resistance by increasing the temperature raising / lowering rate of the heat treatment for producing a liquid crystal display.
  • BHF buffered hydrofluoric acid, mixed liquid of hydrofluoric acid and ammonium fluoride
  • Patent Document 1 discloses SiO 2 —Al 2 O 3 —SrO glass that does not contain B 2 O 3 , but the temperature required for melting is high, which makes manufacturing difficult.
  • Patent Document 2 discloses a SiO 2 —Al 2 O 3 —SrO crystallized glass that does not contain B 2 O 3 , but the temperature required for melting is high, resulting in difficulty in production.
  • Patent Document 3 discloses a glass containing 0 to 3% by weight of B 2 O 3 , but the strain point of the examples is 690 ° C. or lower.
  • Patent Document 4 discloses a glass containing 0 to 5 mol% of B 2 O 3 , but the average coefficient of thermal expansion at 50 to 300 ° C. exceeds 50 ⁇ 10 ⁇ 7 / ° C.
  • Patent Document 5 discloses a glass containing 0 to 5 mol% of B 2 O 3 , but has a large thermal expansion and a high density.
  • an alkali-free glass described in Patent Document 6 has been proposed.
  • the alkali-free glass described in Patent Document 6 has a high strain point, can be molded by a float process, and is suitable for applications such as a display substrate and a photomask substrate.
  • Japanese Laid-Open Patent Publication No. 62-1113735 Japanese Unexamined Patent Publication No. Sho 62-100450 Japanese Laid-Open Patent Publication No. 4-325435 Japanese Patent Laid-Open No. 5-232458 US Pat. No. 5,326,730 Japanese Patent Laid-Open No. 10-45422 Japanese republished patent 2009-148141
  • the object of the present invention is to solve the above-mentioned drawbacks, to have a high strain point and to have a low viscosity, in particular, a low temperature T 4 at which the glass viscosity is 10 4 dPa ⁇ s, and further a protective layer for preventing wrinkles comprising a sulfate. It is providing the manufacturing method of the plate glass which consists of a non-alkali glass which can be efficiently formed in the glass ribbon after shape
  • the present invention is a plate glass manufacturing method in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a molding device, and then the glass ribbon is gradually cooled with a slow cooling device,
  • the plate glass is made of the following alkali-free glass,
  • T st the strain point of the alkali-free glass
  • the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st ⁇ 50 ° C.
  • a plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer is provided.
  • the average coefficient of thermal expansion at 50 to 300 ° C. is 30 ⁇ 10 ⁇ 7 to 43 ⁇ 10 ⁇ 7 / ° C.
  • the glass viscosity is 10 2 dPa ⁇ s.
  • T 2 is 1710 ° C. or lower
  • the temperature T 4 at which the glass viscosity is 10 4 dPa ⁇ s is 1320 ° C.
  • MgO + CaO + SrO + BaO is 17-21,
  • the present invention also relates to a method for producing plate glass, in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a forming apparatus, and then the glass ribbon is gradually cooled with a slow cooling apparatus.
  • the plate glass is made of the following alkali-free glass, When the strain point of the alkali-free glass is T st (° C.), the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st ⁇ 50 ° C.
  • a plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer is provided.
  • the average coefficient of thermal expansion at 50 to 300 ° C. is 30 ⁇ 10 ⁇ 7 to 43 ⁇ 10 ⁇ 7 / ° C.
  • the glass viscosity is 10 2 dPa ⁇ s.
  • T 2 is 1710 ° C. or lower
  • the temperature T 4 at which the glass viscosity is 10 4 dPa ⁇ s is 1320 ° C.
  • MgO + CaO + SrO + BaO is more than 18.2 and 21 or less
  • MgO / (MgO + CaO + SrO + BaO) is 0.25 or more
  • MgO / (MgO + CaO) is 0.3 or more
  • MgO / (MgO + SrO) is 0.60 or more
  • Al 2 O 3 ⁇ (MgO / (MgO + CaO + SrO + BaO) ) Is alkali-free glass of 5.5 or more.
  • this invention provides the plate glass manufactured with the plate glass manufacturing method of this invention.
  • the protective layer for preventing wrinkles of sulfate can be efficiently and uniformly formed on the glass ribbon, and the supply amount of sulfurous acid gas can be saved. As a result, a high-quality plate glass with less wrinkles can be obtained.
  • the plate glass of the present invention is particularly suitable for a display substrate, a photomask substrate and the like for high strain point applications.
  • the glass raw material prepared so that it might become the following glass composition 1 is used.
  • the glass raw material prepared so that it might become the following glass composition 2 is used.
  • MgO + CaO + SrO + BaO is more than 18.2 and 21 or less
  • MgO / (MgO + CaO + SrO + BaO) is 0.25 or more
  • MgO / (MgO + CaO) is 0.3 or more
  • MgO / (MgO + SrO) is 0.60 or more
  • Al 2 O 3 ⁇ (MgO / (MgO + CaO + SrO + BaO) ) Is alkali-free glass of 5.5 or more.
  • the composition range of each component will be described. If the SiO 2 content is less than 66% (mol%, the same unless otherwise specified), the strain point is not sufficiently increased, the thermal expansion coefficient is increased, and the density is increased. Preferably it is 66.5% or more, more preferably 67% or more. If it exceeds 70%, the solubility decreases and the devitrification temperature increases. Preferably it is 69% or less.
  • Al 2 O 3 suppresses the phase separation of the glass, lowers the thermal expansion coefficient and raises the strain point, but if it is less than 12%, this effect does not appear, and other components that increase the expansion increase. As a result, thermal expansion increases. Preferably it is 12.2% or more. If it exceeds 15%, the solubility of the glass may be deteriorated, or the devitrification temperature may be increased. Preferably it is 14.5% or less, More preferably, it is 14% or less, More preferably, it is 13.8% or less.
  • B 2 O 3 can be added up to 1.5% in order to improve the melting reactivity of the glass and lower the devitrification temperature. However, if it is too much, the strain point is lowered. Also, the efficiency in forming a flaw preventing protection layer of sulfate when B 2 O 3 is too large in the glass ribbon is reduced. Therefore, it is preferably 1.3% or less, and more preferably 1% or less. Moreover, it is preferable not to contain substantially considering environmental load.
  • MgO has the characteristics that it does not increase the expansion in alkaline earth and does not excessively lower the strain point, and also improves the solubility.
  • the MgO content is more than 9.5% and not more than 13%. If it is 9.5% or less, the above-mentioned effect due to the addition of MgO is not sufficiently exhibited. However, if it exceeds 13%, the devitrification temperature may increase. 12.5% or less is preferable, 12% or less is more preferable, and 11.5% or less is more preferable.
  • the MgO content is 5 to 9.5%. If it is less than 5%, the above-mentioned effect due to the addition of MgO is not sufficiently exhibited. 6% or more is preferable, and 7% or more is more preferable. However, if it exceeds 9.5%, the devitrification temperature may increase. 9.3% or less is preferable, and 9% or less is more preferable.
  • CaO has the characteristics that it does not increase the expansion in alkaline earth after MgO, and does not excessively lower the strain point, and also improves the solubility.
  • the CaO content is 4 to 9%. If it is less than 4%, the above-described effect due to the addition of CaO is not sufficiently exhibited. However, if it exceeds 9%, the devitrification temperature may increase, or a large amount of phosphorus, which is an impurity in limestone (CaCO 3 ) that is a CaO raw material, may be mixed. It is preferably 7% or less, more preferably 6% or less, and further preferably 5% or less.
  • the CaO content is 4 to 11%.
  • the devitrification temperature may increase, or a large amount of phosphorus, which is an impurity in limestone (CaCO 3 ) that is a CaO raw material, may be mixed. It is preferably 10% or less, more preferably 9% or less, further preferably 7% or less, and particularly preferably 6% or less.
  • SrO improves the solubility without increasing the devitrification temperature of the glass, but if less than 0.5%, this effect does not appear sufficiently.
  • Preferably it is 1.0% or more, More preferably, it is 2.0% or more. However, if it exceeds 4.5%, the expansion coefficient may increase. 4.0% or less is more preferable, and 3.5% or less is more preferable.
  • BaO is not essential, but can be contained to improve solubility. However, if it is too much, the expansion and density of the glass are excessively increased, so the content is made 1% or less. Less than 1% is preferable, 0.5% or less is more preferable, and it is preferable not to contain substantially.
  • ZrO 2 may be contained up to 2% in order to lower the glass melting temperature or to promote crystal precipitation during firing. If it exceeds 2%, the glass becomes unstable or the relative dielectric constant ⁇ of the glass increases. Preferably it is 1.5% or less, More preferably, it is 1.0% or less, More preferably, it is 0.5% or less, and it is especially preferable not to contain substantially.
  • the solubility is poor, and the efficiency in forming a sulfate anti-fogging protective layer on the glass ribbon decreases. .
  • it is 18% or more, More preferably, it is 18.5% or more.
  • it exceeds 21% there is a risk that the thermal expansion coefficient cannot be reduced.
  • the solubility is poor, and the efficiency when forming a protective layer for preventing sulfate wrinkles on the glass ribbon is reduced. To do. If it exceeds 21%, there is a risk that the thermal expansion coefficient cannot be reduced. Preferably it is 20% or less.
  • MgO / (MgO + CaO + SrO + BaO) is 0.4 or more, preferably 0.45 or more.
  • MgO / (MgO + CaO) is 0.4 or more, preferably 0.52 or more, more preferably 0.55 or more.
  • MgO / (MgO + SrO) is 0.6 or more, preferably 0.7 or more.
  • the total amount of MgO, CaO, SrO and BaO satisfies the above and satisfies the following three conditions, thereby increasing the strain point without increasing the devitrification temperature.
  • the temperature T 4 at which the viscosity, particularly the glass viscosity, becomes 10 4 dPa ⁇ s can be lowered.
  • MgO / (MgO + CaO + SrO + BaO) is 0.25 or more, preferably 0.3 or more, more preferably 0.4 or more, and further preferably 0.45 or more.
  • MgO / (MgO + CaO) is 0.3 or more, preferably 0.4 or more, more preferably 0.52 or more, and further preferably 0.55 or more.
  • MgO / (MgO + SrO) is 0.6 or more, preferably 0.7 or more.
  • Al 2 O 3 ⁇ (MgO / (MgO + CaO + SrO + BaO) is preferably 5.5 or more because the Young's modulus can be increased. Preferably it is 5.75 or more, More preferably, it is 6.0 or more, More preferably, it is 6.25 or more, Most preferably, it is 6.5 or more.
  • the efficiency at the time of forming the protective layer for wrinkle prevention in a glass ribbon improves by making a glass raw material contain 600 molppm or more of alkali metal oxides.
  • the reason is as follows. Since alkali-free glass does not contain an alkali metal oxide, even if a high-temperature glass ribbon is exposed to the SO 2 gas atmosphere, a protective layer for preventing wrinkles due to precipitation of alkali metal sulfate cannot be formed.
  • alkaline earth metal sulfates are precipitated instead of alkali metal sulfates.
  • the present inventors added a small amount of alkali metal oxide to the glass raw material, thereby increasing the precipitation effect of alkaline earth metal sulfate and improving the efficiency when forming the protective layer for preventing wrinkles on the glass ribbon. I found out.
  • the content of the alkali metal oxide when used as a substrate glass for various displays.
  • the content of the metal oxide is 2000 mol ppm or less, such a problem will not occur. More preferably, it is 1500 mol ppm or less, More preferably, it is 1300 mol ppm or less, Most preferably, it is 1000 mol ppm or less.
  • the glass raw material used in the present invention preferably contains an alkali metal oxide of 1500 mol ppm or less, more preferably 1300 mol ppm or less, more preferably 1000 mol ppm or less, and more preferably 700 to 900 mol ppm.
  • Na 2 O and K 2 O are preferable from the viewpoint of the balance between the effect of improving the efficiency when forming the protective layer for preventing wrinkles on the glass ribbon and the raw material cost, and Na 2 O is more preferable.
  • the glass raw material does not substantially contain P 2 O 5 . Furthermore, in order to facilitate recycling of the glass, it is preferable that the glass raw material does not substantially contain PbO, As 2 O 3 , or Sb 2 O 3 .
  • ZnO, Fe 2 O 3 , SO 3 , F, Cl, SnO 2 can be added to the glass raw material in a total amount of 5% or less.
  • the glass compositions 1 and 2 have relatively low solubility, it is preferable to use the following as raw materials for each component.
  • Silica sand can be used as the silicon source of SiO 2 , but the proportion of particles having a median particle size D 50 of 20 ⁇ m to 27 ⁇ m, a particle size of 2 ⁇ m or less is 0.3% by volume or less, and the particle size is 100 ⁇ m or more.
  • Using 2.5% by volume or less of silica sand can suppress the agglomeration of the silica sand and dissolve it, so that the silica sand can be easily dissolved, and there is less foam, and a plate glass with high homogeneity and flatness can be obtained. This is preferable.
  • particle size in this specification is the equivalent sphere diameter of silica sand (meaning the primary particle size in the present invention), and specifically, in the particle size distribution of the powder measured by the laser diffraction / scattering method.
  • particle size D 50 means that the volume frequency of particles larger than a certain particle size is 50% of the total powder in the particle size distribution of the powder measured by the laser diffraction method.
  • the particle diameter occupied In other words, it refers to the particle diameter when the cumulative frequency is 50% in the particle size distribution of the powder measured by the laser diffraction method.
  • ratio of particles having a particle diameter of 2 ⁇ m or less and “ratio of particles having a particle diameter of 100 ⁇ m or more” in this specification are measured by measuring the particle size distribution by a laser diffraction / scattering method, for example.
  • the median particle diameter D 50 of silica sand is 25 ⁇ m or less, it is more preferable because dissolution of silica sand becomes easier. Further, the ratio of the particles having a particle diameter of 100 ⁇ m or more in the silica sand is particularly preferably 0% because the silica sand is more easily dissolved.
  • Alkaline earth metal source An alkaline earth metal compound can be used as the alkaline earth metal source.
  • Specific examples of the alkaline earth metal compound include carbonates such as MgCO 3 , CaCO 3 , BaCO 3 , SrCO 3 , (Mg, Ca) CO 3 (dolomite), MgO, CaO, BaO, SrO and the like.
  • Oxides and hydroxides such as Mg (OH) 2 , Ca (OH) 2 , Ba (OH) 2 , and Sr (OH) 2 can be exemplified. It is preferable to contain a hydroxide of a similar metal since the undissolved amount of the SiO 2 component at the time of melting the glass raw material is reduced.
  • the undissolved amount of the SiO 2 component contained in the silica sand increases, the undissolved SiO 2 is taken into the bubbles when the bubbles are generated in the molten glass and gathers near the surface layer of the molten glass. As a result, a difference in the composition ratio of SiO 2 occurs between the surface layer of the molten glass and the portion other than the surface layer, so that the homogeneity of the glass is lowered and the flatness is also lowered.
  • the content of the alkaline earth metal hydroxide is preferably 15 to 100 mol% (MO conversion in terms of MO, where M is an alkaline earth metal element). Conversion), more preferably 30 to 100 mol% (MO conversion), and even more preferably 60 to 100 mol% (MO conversion), the undissolved amount of the SiO 2 component at the time of melting the glass raw material is reduced. Therefore, it is more preferable. As the molar ratio of the hydroxide in the alkaline earth metal source increases, the undissolved amount of the SiO 2 component at the time of melting the glass raw material decreases, so the higher the molar ratio of the hydroxide, the better.
  • the alkaline earth metal source a mixture of an alkaline earth metal hydroxide and a carbonate, an alkaline earth metal hydroxide alone, or the like can be used.
  • the carbonate it is preferable to use at least one of MgCO 3 , CaCO 3 and (Mg, Ca) (CO 3 ) 2 (dolomite).
  • the alkaline earth metal hydroxide it is preferable to use at least one of Mg (OH) 2 and Ca (OH) 2 , and it is particularly preferable to use Mg (OH) 2 .
  • the glass composition 1 contains B 2 O 3, as the boron source B 2 O 3, can be used boron compound.
  • specific examples of the boron compound include orthoboric acid (H 3 BO 3 ), metaboric acid (HBO 2 ), tetraboric acid (H 2 B 4 O 7 ), and anhydrous boric acid (B 2 O 3 ). It is done. In the production of ordinary alkali-free glass, orthoboric acid is used because it is inexpensive and easily available.
  • boric anhydride containing 10 to 100% by mass (in terms of B 2 O 3 ) out of 100% by mass of boron source (in terms of B 2 O 3 ).
  • the boric anhydride is more preferably 20 to 100% by mass, and further preferably 40 to 100% by mass.
  • orthoboric acid is preferable because it is inexpensive and easily available.
  • Manufacture of plate glass is performed in the following procedure, for example.
  • the raw materials of each component are prepared so as to become target components, which are continuously charged into a melting furnace, heated to 1500-1800 ° C. and melted.
  • a plate glass can be obtained by forming this molten glass into a plate-like glass ribbon having a predetermined plate thickness using a molding apparatus, and then cooling the glass ribbon after slow cooling.
  • sulfur dioxide (SO 2 ) gas is supplied to the glass ribbon so as to satisfy the following conditions in the slow cooling furnace.
  • T st strain point of the alkali-free glass
  • the SO 2 gas is supplied so as to achieve the above. If the atmospheric concentration is less than 500 ppm, the precipitation amount of alkaline earth metal sulfate may be reduced. More preferably, it is 1000 ppm or more. If the atmospheric concentration exceeds 20000 ppm, corrosion of the equipment may become a problem.
  • the precipitation amount of an alkaline-earth metal sulfate may decrease. More preferably, it is 1 minute or more.
  • the glass ribbon is preferably brought into contact with the SO 2 gas in an atmosphere having a water vapor dew point of 30 ° C. or higher. If the water vapor dew point is low, the precipitation effect of alkaline earth metal sulfate may not be improved. More preferably, it is 40 degreeC or more, More preferably, it is 50 degreeC or more.
  • the glass of the present invention has a strain point of 710 ° C. or higher, and can suppress thermal shrinkage during panel production. Further, a solid phase crystallization method can be applied as a method for manufacturing a p-Si TFT. In the production method of the present invention, it is possible to supply the SO 2 gas at a higher temperature, it is formed efficiency flaw preventing protection layer consisting of alkaline earth metal sulfates.
  • the strain point is more preferably 715 ° C or higher, and further preferably 720 ° C or higher. Especially preferably, it is 735 degreeC or more. When the strain point is 735 ° C.
  • the strain point of the plate glass of the present invention is 750 ° C. or less.
  • the glass of the present invention has a glass transition point of preferably 760 ° C. or higher, more preferably 770 ° C. or higher, and further preferably 780 ° C. or higher for the same reason as the strain point.
  • the glass of the present invention has an average coefficient of thermal expansion at 50 to 300 ° C. of 30 ⁇ 10 ⁇ 7 to 43 ⁇ 10 ⁇ 7 / ° C., has high thermal shock resistance, and can increase productivity during panel manufacture.
  • the average thermal expansion coefficient at 50 to 300 ° C. is preferably 35 ⁇ 10 ⁇ 7 to 40 ⁇ 10 ⁇ 7 / ° C.
  • the specific gravity of the glass of the present invention is preferably 2.65 or less, more preferably 2.64 or less, and further preferably 2.62 or less.
  • the temperature T 2 at which the viscosity ⁇ becomes 10 2 poise is 1710 ° C. or less, preferably less than 1710 ° C., more preferably 1700 ° C. or less, and further preferably 1690 ° C. or less. Therefore, dissolution is relatively easy.
  • the glass of the present invention has a temperature T 4 at which the viscosity ⁇ becomes 10 4 poise is 1320 ° C. or less, preferably 1315 ° C. or less, more preferably 1310 ° C. or less, and further preferably 1305 ° C. or less, which is suitable for float molding. Yes.
  • the glass of the present invention preferably has a devitrification temperature of 1350 ° C. or lower because molding by the float method is easy. Preferably it is 1340 degrees C or less, More preferably, it is 1330 degrees C or less.
  • the devitrification temperature is obtained by putting crushed glass particles in a platinum dish and performing heat treatment for 17 hours in an electric furnace controlled at a constant temperature. It is an average value of the maximum temperature at which crystals are deposited inside and the minimum temperature at which crystals are not deposited.
  • the glass of the present invention preferably has a Young's modulus of 84 GPa or more, more preferably 86 GPa or more, further 88 GPa or more, and further 90 GPa or more.
  • the glass of the present invention preferably has a photoelastic constant of 31 nm / MPa / cm or less. Due to the birefringence of the glass substrate due to stress generated during the manufacturing process of the liquid crystal display panel and the liquid crystal display device, a phenomenon in which the black display becomes gray and the contrast of the liquid crystal display decreases may be observed. By setting the photoelastic constant to 31 nm / MPa / cm or less, this phenomenon can be suppressed small.
  • the glass of the present invention preferably has a photoelastic constant of 25 nm / MPa / cm or less, considering the ease of securing other physical properties.
  • the photoelastic constant can be measured by a disk compression method.
  • the glass of the present invention preferably has a relative dielectric constant of 5.6 or more.
  • the sensing sensitivity of the touch sensor is improved, the driving voltage is reduced, From the viewpoint of power saving, it is better that the glass substrate has a higher relative dielectric constant.
  • the relative dielectric constant is 5.8 or more, More preferably, it is 6.0 or more, More preferably, it is 6.2 or more, Most preferably, it is 6.4 or more.
  • the relative dielectric constant can be measured by the method described in JIS C-2141.
  • Example 1 Comparative Examples 1 and 2
  • the raw material of each component was prepared so that it might become the target composition shown in Table 1, it melt
  • the content of the alkali metal oxide in the raw material used at this time the content of Na 2 O, the particle size of the silica sand in the used raw material, the median particle size D 50 , the proportion of particles having a particle size of 2 ⁇ m or less, and Table 1 shows the ratio of particles having a diameter of 100 ⁇ m or more.
  • Table 1 also shows the molar ratio (in terms of MO) of the hydroxide raw material in the alkaline earth metal.
  • the obtained glass was mirror-polished and then heat-treated in an SO 2 gas atmosphere at the heat treatment temperature, heat treatment time, SO 2 gas concentration and water vapor dew point shown in Table 2.
  • the sulfate precipitation state on the surface of the obtained glass was measured as the surface S concentration (mass%) by fluorescent X-rays.
  • Table 2 also shows the strain point and surface S concentration (% by mass) of the glass.
  • the number of counts of S-k ⁇ rays is measured using a ⁇ 10 mm mask under the conditions shown in Table 3. After mirror-polishing glass with a known S concentration, the count number of S-k ⁇ rays was measured with a ⁇ 10 mm mask under the conditions shown in Table 3, and the S-k ⁇ ray count number and S concentration (mass%) Get correlation. By using the obtained correlation, the Sk ⁇ ray count number of the glass sample on which the sulfate salt is deposited is converted into the S concentration (mass%).
  • the surface S concentration is preferably 0.15% by mass or more, and more preferably 0.2% by mass or more.
  • Example 2 to 4 The raw materials of each component were prepared so as to have the target composition shown in Table 4, and were melted at a temperature of 1550 ° C. for 1 hour using a platinum crucible. After dissolution, it was poured out into a carbon plate, held at glass transition point + 30 ° C. for 1 hour, cooled at 1 ° C./min, and gradually cooled.
  • the content of the alkali metal oxide in the raw material used at this time the content of Na 2 O, the particle size of the silica sand in the used raw material, the median particle size D 50 , the proportion of particles having a particle size of 2 ⁇ m or less, and Table 4 shows the ratio of particles having a diameter of 100 ⁇ m or more.
  • Table 4 also shows the molar ratio (MO conversion) of the hydroxide raw material in the alkaline earth metal.
  • the obtained glass was cut, and after mirror polishing, heat treatment was performed in an SO 2 gas atmosphere at the heat treatment temperature, heat treatment time, SO 2 gas concentration, and water vapor dew point shown in Table 5.
  • the sulfate precipitation state on the surface of the obtained glass was measured as the surface S concentration (mass%) by fluorescent X-rays.
  • Table 5 also shows the strain point and surface S concentration (mass%) of the glass.
  • the plate glass obtained by the present invention has a high strain point and is suitable for uses such as a display substrate and a photomask substrate. Moreover, it is suitable also for uses, such as a board

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Abstract

The present invention relates to a method for producing plate glass by melting glass starting materials to form a molten glass, then molding the molten glass into plate-like glass ribbons using a molding device, and gradually cooling the glass ribbons with a gradual cooling device, wherein by means of the method for producing plate glass, the plate glass is formed from the following alkali-free glass and SO2 gas is fed such that when the strain point of the alkali-free glass is Tst (ºC), the time when the ambient air concentration directly underneath the bottom surface of the glass ribbons becomes 500 to 20,000 ppm is 30 seconds or greater at a temperature within a range of Tst + 70ºC to Tst — 50ºC. By mol% in terms of oxide, the alkali-free glass comprises 66 to 70 of SiO2, 12 to 15 of Al­2O3, 0 to 1.5 of B2O3, greater than 9.5 but no greater than 13 of MgO, 4 to 9 of CaO, 0.5 to 4.5 of SrO, 0 to 1 of BaO, and 0 to 2 of ZrO2 such that MgO + CaO + SrO + BaO is 17 to 21, MgO/(MgO + CaO + SrO + BaO) is 0.40 or greater, MgO/(MgO + CaO) is 0.40 or greater, and MgO/(MgO + SrO) is 0.60 or greater, and has a stress point of 710 to 750ºC, an average thermal expansion coefficient at 50 to 300ºC of 30 × 10-7 to 43 × 10-7/ºC, a temperature T2 at which glass viscosity becomes 102dPa·s of 1,710ºC, and a temperature T4 at which glass viscosity becomes 104dPa·s of 1,320ºC.

Description

板ガラスの製造方法Sheet glass manufacturing method
　本発明は、各種ディスプレイ用基板ガラスやフォトマスク用基板ガラスとして好適な、無アルカリガラスからなる板ガラスの製造方法に関する。
　以下、本明細書において、「無アルカリ」と言った場合、アルカリ金属酸化物（Ｌｉ２Ｏ、Ｎａ２Ｏ、Ｋ２Ｏ）の含有量が２０００モルｐｐｍ以下であることを意味する。 The present invention relates to a method for producing a plate glass made of non-alkali glass, which is suitable as a substrate glass for various displays and a substrate glass for a photomask.
Hereinafter, in the present specification, the phrase “no alkali” means that the content of alkali metal oxides (Li 2 O, Na 2 O, K 2 O) is 2000 mol ppm or less.
　従来、各種ディスプレイ用基板ガラス、特に表面に金属ないし酸化物薄膜等を形成するものでは、以下に示す特性が要求されてきた。
（１）アルカリ金属酸化物を含有していると、アルカリ金属イオンが薄膜中に拡散して膜特性を劣化させるため、アルカリ金属酸化物の含有量がきわめて低いこと、具体的には、アルカリ金属酸化物の含有量が２０００モルｐｐｍ以下であること。
（２）薄膜形成工程で高温にさらされる際に、ガラスの変形およびガラスの構造安定化に伴う収縮（熱収縮）を最小限に抑えうるように、歪点が高いこと。 Conventionally, the following characteristics have been required for various display substrate glasses, particularly those in which a metal or oxide thin film is formed on the surface.
(1) When an alkali metal oxide is contained, alkali metal ions diffuse into the thin film and deteriorate the film characteristics. Therefore, the content of the alkali metal oxide is extremely low. The oxide content is 2000 mol ppm or less.
(2) When exposed to a high temperature in the thin film forming process, the strain point is high so that the deformation (thermal shrinkage) associated with glass deformation and glass structural stabilization can be minimized.
（３）半導体形成に用いる各種薬品に対して充分な化学耐久性を有すること。特にＩＴＯのエッチングに用いる塩酸を含有する薬液、金属電極のエッチングに用いる各種の酸（硝酸、硫酸等）、レジスト剥離液のアルカリ等に対して耐久性のあること。
（４）内部および表面に欠点（泡、脈理、インクルージョン、ピット、キズ等）がないこと。 (3) Sufficient chemical durability against various chemicals used for semiconductor formation. In particular, it should be resistant to chemicals containing hydrochloric acid used for etching ITO, various acids (nitric acid, sulfuric acid, etc.) used for etching metal electrodes, and alkalis for resist stripping solutions.
(4) There are no defects (bubbles, striae, inclusions, pits, scratches, etc.) inside and on the surface.
　上記の要求に加えて、近年では、以下のような状況にある。
（５）ディスプレイの軽量化が要求され、ガラス自身も密度の小さいガラスが望まれる。
（６）ディスプレイの軽量化が要求され、基板ガラスの薄板化が望まれる。 In addition to the above requirements, in recent years, there are the following situations.
(5) The weight reduction of the display is required, and the glass itself is desired to have a low density glass.
(6) A reduction in weight of the display is required, and a reduction in the thickness of the substrate glass is desired.
（７）これまでのアモルファスシリコン（ａ－Ｓｉ）タイプの液晶ディスプレイに加え、若干熱処理温度の高い多結晶シリコン（ｐ－Ｓｉ）タイプの液晶ディスプレイが作製されるようになってきた（ａ－Ｓｉ：約３５０℃→ｐ－Ｓｉ：３５０～５５０℃）。
（８）液晶ディスプレイ作製熱処理の昇降温速度を速くして、生産性を上げたり耐熱衝撃性を上げるために、ガラスの平均熱膨張係数の小さいガラスが求められる。 (7) In addition to the conventional amorphous silicon (a-Si) type liquid crystal display, a polycrystalline silicon (p-Si) type liquid crystal display having a slightly higher heat treatment temperature has been produced (a-Si). : About 350 ° C. → p-Si: 350 to 550 ° C.).
(8) A glass having a small average thermal expansion coefficient is required to increase productivity and thermal shock resistance by increasing the temperature raising / lowering rate of the heat treatment for producing a liquid crystal display.
　一方、エッチングのドライ化が進み、耐ＢＨＦ性に対する要求が弱くなってきている（ＢＨＦ：バッファードフッ酸、フッ酸とフッ化アンモニウムの混合液）。これまでのガラスは、耐ＢＨＦ性を良くするために、Ｂ２Ｏ３を６～１０モル％含有するガラスが多く用いられてきた。しかし、Ｂ２Ｏ３は歪点を下げる傾向がある。Ｂ２Ｏ３を含有しないまたは含有量の少ない無アルカリガラスの例としては以下のようなものがある。 On the other hand, the dryness of etching has progressed, and the demand for BHF resistance has been weakened (BHF: buffered hydrofluoric acid, mixed liquid of hydrofluoric acid and ammonium fluoride). Conventionally, glass containing 6 to 10 mol% of B 2 O 3 has been often used in order to improve BHF resistance. However, B 2 O 3 tends to lower the strain point. Examples of non-alkali glass that does not contain B 2 O 3 or have a low content are as follows.
　特許文献１にはＢ２Ｏ３を含有しない、ＳｉＯ２－Ａｌ２Ｏ３－ＳｒＯガラスが開示されているが、溶解に必要な温度が高く製造に困難を生ずる。 Patent Document 1 discloses SiO 2 —Al 2 O 3 —SrO glass that does not contain B 2 O 3 , but the temperature required for melting is high, which makes manufacturing difficult.
　特許文献２にはＢ２Ｏ３を含有しない、ＳｉＯ２－Ａｌ２Ｏ３－ＳｒＯ結晶化ガラスが開示されているが、溶解に必要な温度が高く製造に困難を生ずる。 Patent Document 2 discloses a SiO 2 —Al 2 O 3 —SrO crystallized glass that does not contain B 2 O 3 , but the temperature required for melting is high, resulting in difficulty in production.
　特許文献３にはＢ２Ｏ３を０～３重量％含有するガラスが開示されているが、実施例の歪点が６９０℃以下である。 Patent Document 3 discloses a glass containing 0 to 3% by weight of B 2 O 3 , but the strain point of the examples is 690 ° C. or lower.
　特許文献４にはＢ２Ｏ３を０～５モル％含有するガラスが開示されているが、５０～３００℃での平均熱膨張係数が５０×１０-７／℃を超える。 Patent Document 4 discloses a glass containing 0 to 5 mol% of B 2 O 3 , but the average coefficient of thermal expansion at 50 to 300 ° C. exceeds 50 × 10 −7 / ° C.
　特許文献５にはＢ２Ｏ３を０～５モル％含有するガラスが開示されているが、熱膨張が大きく、密度も大きい。 Patent Document 5 discloses a glass containing 0 to 5 mol% of B 2 O 3 , but has a large thermal expansion and a high density.
　特許文献１～５に記載のガラスにおける問題点を解決するため、特許文献６に記載の無アルカリガラスが提案されている。特許文献６に記載の無アルカリガラスは、歪点が高く、フロート法による成形ができ、ディスプレイ用基板、フォトマスク用基板等の用途に好適であるとされている。 In order to solve the problems in the glasses described in Patent Documents 1 to 5, an alkali-free glass described in Patent Document 6 has been proposed. The alkali-free glass described in Patent Document 6 has a high strain point, can be molded by a float process, and is suitable for applications such as a display substrate and a photomask substrate.
　しかしながら、高品質のｐ－Ｓｉ　ＴＦＴの製造方法として固相結晶化法があるが、これを実施するためには、歪点をさらに高くすることが求められる。
　一方、ガラス製造プロセス、特に溶解、成形における要請から、ガラスの粘性、特にガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４を低くすることが求められている。 However, there is a solid-phase crystallization method as a method for producing a high-quality p-Si TFT. In order to implement this, it is required to further increase the strain point.
On the other hand, due to demands in the glass production process, particularly melting and molding, it is required to lower the temperature T 4 at which the viscosity of the glass, particularly the glass viscosity, becomes 10 4 dPa · s.
　また、板状に成形した後のガラスリボンのキズ付き防止の目的で、成形後のガラスリボンに対し、徐冷炉内で亜硫酸（ＳＯ２）ガスを吹き付けて、ガラスリボンの下面に硫酸塩からなる疵防止用保護層を形成することが知られている（特許文献７参照）。
　しかしながら、無アルカリガラスの場合は、疵防止用保護層をガラスリボンに効率よく形成することが困難であり、設備面での検討がなされていたが、設備構成上の制約等がある場合がある。 In addition, for the purpose of preventing scratches on the glass ribbon after being formed into a plate shape, a sulfurous acid (SO 2 ) gas is sprayed on the glass ribbon after being formed in a slow cooling furnace, so that the bottom surface of the glass ribbon is made of sulfate. It is known to form a protective layer for prevention (see Patent Document 7).
However, in the case of non-alkali glass, it is difficult to efficiently form a protective layer for preventing wrinkles on a glass ribbon, and studies have been made in terms of equipment, but there may be restrictions on the equipment configuration, etc. .
日本国特開昭６２－１１３７３５号公報Japanese Laid-Open Patent Publication No. 62-1113735 日本国特開昭６２－１００４５０号公報Japanese Unexamined Patent Publication No. Sho 62-100450 日本国特開平４－３２５４３５号公報Japanese Laid-Open Patent Publication No. 4-325435 日本国特開平５－２３２４５８号公報Japanese Patent Laid-Open No. 5-232458 米国特許第５３２６７３０号明細書US Pat. No. 5,326,730 日本国特開平１０－４５４２２号公報Japanese Patent Laid-Open No. 10-45422 日本国再公表特許２００９－１４８１４１号公報Japanese republished patent 2009-148141
　本発明の目的は、上記欠点を解決し、歪点が高く、かつ、低粘性、特にガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４が低く、さらに、硫酸塩からなる疵防止用保護層を、板状に成形した後のガラスリボンに効率よく形成することができる、無アルカリガラスからなる板ガラスの製造方法を提供することにある。 The object of the present invention is to solve the above-mentioned drawbacks, to have a high strain point and to have a low viscosity, in particular, a low temperature T 4 at which the glass viscosity is 10 4 dPa · s, and further a protective layer for preventing wrinkles comprising a sulfate. It is providing the manufacturing method of the plate glass which consists of a non-alkali glass which can be efficiently formed in the glass ribbon after shape | molding this in plate shape.
　本発明は、ガラス原料を溶解し溶融ガラスとし、該溶融ガラスを成形装置にて板状のガラスリボンに成形した後、該ガラスリボンを徐冷装置にて徐冷する板ガラス製造方法であって、
　前記板ガラスが下記の無アルカリガラスからなり、
　前記無アルカリガラスの歪点をＴｓｔ（℃）とするとき、Ｔｓｔ＋７０℃～Ｔｓｔ－５０℃の温度域で、前記ガラスリボンの下面の直下の雰囲気濃度が５００～２００００ｐｐｍとなる時間が３０秒以上となるように、ＳＯ２ガスを供給する板ガラス製造方法を提供する。
　歪点が７１０～７５０℃であって、５０～３００℃での平均熱膨張係数が３０×１０-７～４３×１０-７／℃であって、ガラス粘度が１０２ｄＰａ・ｓとなる温度Ｔ２が１７１０℃以下であって、ガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４が１３２０℃以下であって、
酸化物基準のモル％表示で
ＳｉＯ２ 　　　　　　 ６６～７０、
Ａｌ２Ｏ３　　　　　　１２～１５、
Ｂ２Ｏ３　　　　　　　　０～１．５、
ＭｇＯ 　　　　　　　 ９．５超１３以下、
ＣａＯ 　　　　　　　 ４～９、
ＳｒＯ　　　　　　　　０．５～４．５、
ＢａＯ 　　　　　　　 ０～１、
ＺｒＯ２　　　　　　　 ０～２、を含有し、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１７～２１であり、
ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上である無アルカリガラス。 The present invention is a plate glass manufacturing method in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a molding device, and then the glass ribbon is gradually cooled with a slow cooling device,
The plate glass is made of the following alkali-free glass,
When the strain point of the alkali-free glass is T st (° C.), the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st −50 ° C. A plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer is provided.
Temperature at which the strain point is 710 to 750 ° C., the average coefficient of thermal expansion at 50 to 300 ° C. is 30 × 10 −7 to 43 × 10 −7 / ° C., and the glass viscosity is 10 2 dPa · s. T 2 is 1710 ° C. or lower, and the temperature T 4 at which the glass viscosity is 10 4 dPa · s is 1320 ° C. or lower,
SiO 2 66 to 70 in terms of mol% based on oxide,
Al 2 O 3 12-15,
B 2 O 3 0-1.5,
MgO more than 9.5 and 13 or less,
CaO 4-9,
SrO 0.5-4.5,
BaO 0 ~ 1,
ZrO 2 0-2,
MgO + CaO + SrO + BaO is 17-21,
An alkali-free glass in which MgO / (MgO + CaO + SrO + BaO) is 0.40 or more, MgO / (MgO + CaO) is 0.40 or more, and MgO / (MgO + SrO) is 0.60 or more.
　また、本発明は、ガラス原料を溶解し溶融ガラスとし、該溶融ガラスを成形装置にて板状のガラスリボンに成形した後、該ガラスリボンを徐冷装置にて徐冷する板ガラス製造方法であって、
　前記板ガラスが下記の無アルカリガラスからなり、
　前記無アルカリガラスの歪点をＴｓｔ（℃）とするとき、Ｔｓｔ＋７０℃～Ｔｓｔ－５０℃の温度域で、前記ガラスリボンの下面の直下の雰囲気濃度が５００～２００００ｐｐｍとなる時間が３０秒以上となるように、ＳＯ２ガスを供給する板ガラス製造方法を提供する。
　歪点が７１０～７５０℃であって、５０～３００℃での平均熱膨張係数が３０×１０-７～４３×１０-７／℃であって、ガラス粘度が１０２ｄＰａ・ｓとなる温度Ｔ２が１７１０℃以下であって、ガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４が１３２０℃以下であって、
酸化物基準のモル％表示で
ＳｉＯ２ 　　　　　　 ６６～７０、
Ａｌ２Ｏ３　　　　　　１２～１５、
Ｂ２Ｏ３　　　　　　　　０～１．５、
ＭｇＯ 　　　　　　　 ５～９．５、
ＣａＯ 　　　　　　　 ４～１１、
ＳｒＯ　　　　　　　　０．５～４．５、
ＢａＯ 　　　　　　　 ０～１、
ＺｒＯ２　　　　　　　 ０～２、を含有し、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１８．２超２１以下であり、
ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．２５以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．３以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上であり、Ａｌ２Ｏ３×（ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ））が５．５以上である無アルカリガラス。 The present invention also relates to a method for producing plate glass, in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a forming apparatus, and then the glass ribbon is gradually cooled with a slow cooling apparatus. And
The plate glass is made of the following alkali-free glass,
When the strain point of the alkali-free glass is T st (° C.), the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st −50 ° C. A plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer is provided.
Temperature at which the strain point is 710 to 750 ° C., the average coefficient of thermal expansion at 50 to 300 ° C. is 30 × 10 −7 to 43 × 10 −7 / ° C., and the glass viscosity is 10 2 dPa · s. T 2 is 1710 ° C. or lower, and the temperature T 4 at which the glass viscosity is 10 4 dPa · s is 1320 ° C. or lower,
SiO 2 66 to 70 in terms of mol% based on oxide,
Al 2 O 3 12-15,
B 2 O 3 0-1.5,
MgO 5 to 9.5,
CaO 4-11,
SrO 0.5-4.5,
BaO 0 ~ 1,
ZrO 2 0-2,
MgO + CaO + SrO + BaO is more than 18.2 and 21 or less,
MgO / (MgO + CaO + SrO + BaO) is 0.25 or more, MgO / (MgO + CaO) is 0.3 or more, MgO / (MgO + SrO) is 0.60 or more, and Al 2 O 3 × (MgO / (MgO + CaO + SrO + BaO) ) Is alkali-free glass of 5.5 or more.
　また、本発明は、本発明の板ガラス製造方法で製造された板ガラスを提供する。 Moreover, this invention provides the plate glass manufactured with the plate glass manufacturing method of this invention.
　本発明の板ガラス製造方法では、硫酸塩の疵防止用保護層をガラスリボンに効率よく均一に形成することができるとともに、亜硫酸ガスの供給量も節約することができる。その結果、疵の少ない高品質な板ガラスを得ることができる。
　本発明の板ガラスは、特に高歪点用途のディスプレイ用基板、フォトマスク用基板等に好適である。 In the method for producing sheet glass of the present invention, the protective layer for preventing wrinkles of sulfate can be efficiently and uniformly formed on the glass ribbon, and the supply amount of sulfurous acid gas can be saved. As a result, a high-quality plate glass with less wrinkles can be obtained.
The plate glass of the present invention is particularly suitable for a display substrate, a photomask substrate and the like for high strain point applications.
　以下、本発明の板ガラス製造方法を説明する。 Hereinafter, the plate glass manufacturing method of the present invention will be described.
　本発明の板ガラスの製造方法では、下記ガラス組成１となるように調合したガラス原料を用いる。
　酸化物基準のモル％表示で
ＳｉＯ２ 　　　　　　 ６６～７０、
Ａｌ２Ｏ３　　　　　　１２～１５、
Ｂ２Ｏ３　　　　　　　　０～１．５、
ＭｇＯ 　　　　　　　 ９．５超１３以下、
ＣａＯ 　　　　　　　 ４～９、
ＳｒＯ　　　　　　　　０．５～４．５、
ＢａＯ 　　　　　　　 ０～１、
ＺｒＯ２　　　　　　　 ０～２、を含有し、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１７～２１であり、
ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上である無アルカリガラス。 In the manufacturing method of the plate glass of this invention, the glass raw material prepared so that it might become the following glass composition 1 is used.
SiO 2 66 to 70 in terms of mol% based on oxide,
Al 2 O 3 12-15,
B 2 O 3 0-1.5,
MgO more than 9.5 and 13 or less,
CaO 4-9,
SrO 0.5-4.5,
BaO 0 ~ 1,
ZrO 2 0-2,
MgO + CaO + SrO + BaO is 17-21,
An alkali-free glass in which MgO / (MgO + CaO + SrO + BaO) is 0.40 or more, MgO / (MgO + CaO) is 0.40 or more, and MgO / (MgO + SrO) is 0.60 or more.
　また、本発明の板ガラス製造方法では、下記ガラス組成２となるように調合したガラス原料を用いる。
　酸化物基準のモル％表示で
ＳｉＯ２ 　　　　　　 ６６～７０、
Ａｌ２Ｏ３　　　　　　１２～１５、
Ｂ２Ｏ３　　　　　　　　０～１．５、
ＭｇＯ 　　　　　　　 ５～９．５、
ＣａＯ 　　　　　　　 ４～１１、
ＳｒＯ　　　　　　　　０．５～４．５、
ＢａＯ 　　　　　　　 ０～１、
ＺｒＯ２　　　　　　　 ０～２、を含有し、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１８．２超２１以下であり、
ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．２５以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．３以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上であり、Ａｌ２Ｏ３×（ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ））が５．５以上である無アルカリガラス。 Moreover, in the plate glass manufacturing method of this invention, the glass raw material prepared so that it might become the following glass composition 2 is used.
SiO 2 66 to 70 in terms of mol% based on oxide,
Al 2 O 3 12-15,
B 2 O 3 0-1.5,
MgO 5 to 9.5,
CaO 4-11,
SrO 0.5-4.5,
BaO 0 ~ 1,
ZrO 2 0-2,
MgO + CaO + SrO + BaO is more than 18.2 and 21 or less,
MgO / (MgO + CaO + SrO + BaO) is 0.25 or more, MgO / (MgO + CaO) is 0.3 or more, MgO / (MgO + SrO) is 0.60 or more, and Al 2 O 3 × (MgO / (MgO + CaO + SrO + BaO) ) Is alkali-free glass of 5.5 or more.
　次に各成分の組成範囲について説明する。ＳｉＯ２は６６％（モル％、以下特記しないかぎり同じ）未満では、歪点が充分に上がらず、かつ、熱膨張係数が増大し、密度が上昇する。好ましくは６６．５％以上、より好ましくは６７％以上である。７０％超では、溶解性が低下し、失透温度が上昇する。好ましくは６９％以下である。 Next, the composition range of each component will be described. If the SiO 2 content is less than 66% (mol%, the same unless otherwise specified), the strain point is not sufficiently increased, the thermal expansion coefficient is increased, and the density is increased. Preferably it is 66.5% or more, more preferably 67% or more. If it exceeds 70%, the solubility decreases and the devitrification temperature increases. Preferably it is 69% or less.
　Ａｌ２Ｏ３はガラスの分相性を抑制し、熱膨脹係数を下げ、歪点を上げるが、１２％未満ではこの効果があらわれず、また、ほかの膨張を上げる成分を増加させることになるため、結果的に熱膨張が大きくなる。好ましくは１２．２％以上である。１５％超ではガラスの溶解性が悪くなったり、失透温度を上昇させるおそれがある。好ましくは１４．５％以下、より好ましくは１４％以下、さらに好ましくは１３．８％以下である。 Al 2 O 3 suppresses the phase separation of the glass, lowers the thermal expansion coefficient and raises the strain point, but if it is less than 12%, this effect does not appear, and other components that increase the expansion increase. As a result, thermal expansion increases. Preferably it is 12.2% or more. If it exceeds 15%, the solubility of the glass may be deteriorated, or the devitrification temperature may be increased. Preferably it is 14.5% or less, More preferably, it is 14% or less, More preferably, it is 13.8% or less.
　Ｂ２Ｏ３は、ガラスの溶解反応性をよくし、また、失透温度を低下させるため１．５％まで添加できる。しかし、多すぎると歪点が低くなる。また、Ｂ２Ｏ３が多すぎるとガラスリボンに硫酸塩の疵防止用保護層を形成する際の効率が低下する。
　したがって１．３％以下が好ましく、１％以下がより好ましい。また、環境負荷を考慮すると実質的に含有しないことが好ましい。 B 2 O 3 can be added up to 1.5% in order to improve the melting reactivity of the glass and lower the devitrification temperature. However, if it is too much, the strain point is lowered. Also, the efficiency in forming a flaw preventing protection layer of sulfate when B 2 O 3 is too large in the glass ribbon is reduced.
Therefore, it is preferably 1.3% or less, and more preferably 1% or less. Moreover, it is preferable not to contain substantially considering environmental load.
　ＭｇＯは、アルカリ土類の中では膨張を高くせず、かつ歪点を過大には低下させないという特徴を有し、溶解性も向上させる。
　ここで、ガラス組成１では、ＭｇＯ含有量が９．５％超１３％以下である。９．５％以下では上述したＭｇＯ添加による効果が十分あらわれない。しかし、１３％を超えると、失透温度が上昇するおそれがある。１２．５％以下が好ましく、１２％以下がより好ましく、１１．５％以下がさらに好ましい。
　一方、ガラス組成２では、ＭｇＯ含有量が５～９．５％である。５％未満では上述したＭｇＯ添加による効果が十分あらわれない。６％以上が好ましく、７％以上がより好ましい。しかし、９．５％を超えると、失透温度が上昇するおそれがある。９．３％以下が好ましく、９％以下がより好ましい。 MgO has the characteristics that it does not increase the expansion in alkaline earth and does not excessively lower the strain point, and also improves the solubility.
Here, in the glass composition 1, the MgO content is more than 9.5% and not more than 13%. If it is 9.5% or less, the above-mentioned effect due to the addition of MgO is not sufficiently exhibited. However, if it exceeds 13%, the devitrification temperature may increase. 12.5% or less is preferable, 12% or less is more preferable, and 11.5% or less is more preferable.
On the other hand, in the glass composition 2, the MgO content is 5 to 9.5%. If it is less than 5%, the above-mentioned effect due to the addition of MgO is not sufficiently exhibited. 6% or more is preferable, and 7% or more is more preferable. However, if it exceeds 9.5%, the devitrification temperature may increase. 9.3% or less is preferable, and 9% or less is more preferable.
　ＣａＯは、ＭｇＯに次いでアルカリ土類中では膨張を高くせず、かつ歪点を過大には低下させないという特徴を有し、溶解性も向上させる。
　ここで、ガラス組成１では、ＣａＯ含有量が４～９％である。４％未満では上述したＣａＯ添加による効果が十分あらわれない。しかし、９％を超えると、失透温度が上昇したりＣａＯ原料である石灰石（ＣａＣＯ３）中の不純物であるリンが、多く混入するおそれがある。７％以下が好ましく、６％以下がより好ましく、５％以下がさらに好ましい。
　一方、ガラス組成２では、ＣａＯ含有量が４～１１％である。４％未満では上述したＣａＯ添加による効果が十分あらわれない。５％以上が好ましい。しかし、１１％を超えると、失透温度が上昇したりＣａＯ原料である石灰石（ＣａＣＯ３）中の不純物であるリンが、多く混入するおそれがある。１０％以下が好ましく、９％以下がより好ましく、７％以下がさらに好ましく、６％以下が特に好ましい。 CaO has the characteristics that it does not increase the expansion in alkaline earth after MgO, and does not excessively lower the strain point, and also improves the solubility.
Here, in the glass composition 1, the CaO content is 4 to 9%. If it is less than 4%, the above-described effect due to the addition of CaO is not sufficiently exhibited. However, if it exceeds 9%, the devitrification temperature may increase, or a large amount of phosphorus, which is an impurity in limestone (CaCO 3 ) that is a CaO raw material, may be mixed. It is preferably 7% or less, more preferably 6% or less, and further preferably 5% or less.
On the other hand, in the glass composition 2, the CaO content is 4 to 11%. If it is less than 4%, the above-described effect due to the addition of CaO is not sufficiently exhibited. 5% or more is preferable. However, if it exceeds 11%, the devitrification temperature may increase, or a large amount of phosphorus, which is an impurity in limestone (CaCO 3 ) that is a CaO raw material, may be mixed. It is preferably 10% or less, more preferably 9% or less, further preferably 7% or less, and particularly preferably 6% or less.
　ＳｒＯは、ガラスの失透温度を上昇させず溶解性を向上させるが、０．５％未満ではこの効果が十分あらわれない。好ましくは１．０％以上、さらに好ましくは２．０％以上である。しかし、４．５％を超えると膨脹係数が増大するおそれがある。４．０％以下がより好ましく、３．５％以下がさらに好ましい。 SrO improves the solubility without increasing the devitrification temperature of the glass, but if less than 0.5%, this effect does not appear sufficiently. Preferably it is 1.0% or more, More preferably, it is 2.0% or more. However, if it exceeds 4.5%, the expansion coefficient may increase. 4.0% or less is more preferable, and 3.5% or less is more preferable.
　ＢａＯは必須ではないが溶解性向上のために含有できる。しかし、多すぎるとガラスの膨張と密度を過大に増加させるので１％以下とする。１％未満が好ましく、０．５％以下がより好ましく、さらに実質的に含有しないことが好ましい。 BaO is not essential, but can be contained to improve solubility. However, if it is too much, the expansion and density of the glass are excessively increased, so the content is made 1% or less. Less than 1% is preferable, 0.5% or less is more preferable, and it is preferable not to contain substantially.
　ＺｒＯ２は、ガラス溶融温度を低下させるために、または焼成時の結晶析出を促進するために、２％まで含有してもよい。２％超ではガラスが不安定になる、またはガラスの比誘電率εが大きくなる。好ましくは１．５％以下、より好ましくは１．０％以下、さらに好ましくは０．５％以下であり、実質的に含有しないことが特に好ましい。 ZrO 2 may be contained up to 2% in order to lower the glass melting temperature or to promote crystal precipitation during firing. If it exceeds 2%, the glass becomes unstable or the relative dielectric constant ε of the glass increases. Preferably it is 1.5% or less, More preferably, it is 1.0% or less, More preferably, it is 0.5% or less, and it is especially preferable not to contain substantially.
　ガラス組成１において、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯは合量で１７％よりも少ないと、溶解性に乏しく、また、ガラスリボンに硫酸塩の疵防止用保護層を形成する際の効率が低下する。好ましくは１８％以上、さらに好ましくは１８．５％以上である。２１％よりも多いと、熱膨張係数を小さくできないという難点が生じるおそれがある。好ましくは２０％以下である。
　ガラス組成２において、ＭｇＯ、ＣａＯ、ＳｒＯ、ＢａＯは合量で１８．２％以下だと、溶解性に乏しく、また、ガラスリボンに硫酸塩の疵防止用保護層を形成する際の効率が低下する。２１％よりも多いと、熱膨張係数を小さくできないという難点が生じるおそれがある。好ましくは２０％以下である。 In the glass composition 1, if the total amount of MgO, CaO, SrO, and BaO is less than 17%, the solubility is poor, and the efficiency in forming a sulfate anti-fogging protective layer on the glass ribbon decreases. . Preferably it is 18% or more, More preferably, it is 18.5% or more. If it exceeds 21%, there is a risk that the thermal expansion coefficient cannot be reduced. Preferably it is 20% or less.
When the total amount of MgO, CaO, SrO, and BaO in the glass composition 2 is 18.2% or less, the solubility is poor, and the efficiency when forming a protective layer for preventing sulfate wrinkles on the glass ribbon is reduced. To do. If it exceeds 21%, there is a risk that the thermal expansion coefficient cannot be reduced. Preferably it is 20% or less.
　ガラス組成１においては、ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯの合量が上記を満たし、かつ、下記３条件を満たすことにより、失透温度を上昇させることなしに、歪点を上昇させ、さらにガラスの粘性、特にガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４を下げることができる。
　ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．４以上であり、好ましくは０．４５以上である。
　ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．４以上であり、好ましくは０．５２以上、さらに好ましくは０．５５以上である。
　ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６以上であり、好ましくは０．７以上である。 In the glass composition 1, when the total amount of MgO, CaO, SrO and BaO satisfies the above and satisfies the following three conditions, the strain point is increased without increasing the devitrification temperature. The temperature T 4 at which the viscosity, particularly the glass viscosity, becomes 10 4 dPa · s can be lowered.
MgO / (MgO + CaO + SrO + BaO) is 0.4 or more, preferably 0.45 or more.
MgO / (MgO + CaO) is 0.4 or more, preferably 0.52 or more, more preferably 0.55 or more.
MgO / (MgO + SrO) is 0.6 or more, preferably 0.7 or more.
　ガラス組成２においては、ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯの合量が上記を満たし、かつ、下記３条件を満たすことにより、失透温度を上昇させることなしに、歪点を上昇させ、さらにガラスの粘性、特にガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４を下げることができる。
　ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．２５以上であり、好ましくは０．３以上、より好ましく０．４以上であり、さらに好ましくは０．４５以上である。
　ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．３以上であり、好ましくは０．４以上であり、より好ましくは０．５２以上、さらに好ましくは０．５５以上である。
　ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６以上であり、好ましくは０．７以上である。 In the glass composition 2, the total amount of MgO, CaO, SrO and BaO satisfies the above and satisfies the following three conditions, thereby increasing the strain point without increasing the devitrification temperature. The temperature T 4 at which the viscosity, particularly the glass viscosity, becomes 10 4 dPa · s can be lowered.
MgO / (MgO + CaO + SrO + BaO) is 0.25 or more, preferably 0.3 or more, more preferably 0.4 or more, and further preferably 0.45 or more.
MgO / (MgO + CaO) is 0.3 or more, preferably 0.4 or more, more preferably 0.52 or more, and further preferably 0.55 or more.
MgO / (MgO + SrO) is 0.6 or more, preferably 0.7 or more.
　ガラス組成２において、Ａｌ２Ｏ３×（ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ））が５．５以上であることがヤング率を高められるので好ましい。好ましくは５．７５以上、より好ましくは６．０以上、さらに好ましくは６．２５以上、特に好ましくは６．５以上である。 In the glass composition 2, Al 2 O 3 × (MgO / (MgO + CaO + SrO + BaO)) is preferably 5.5 or more because the Young's modulus can be increased. Preferably it is 5.75 or more, More preferably, it is 6.0 or more, More preferably, it is 6.25 or more, Most preferably, it is 6.5 or more.
　本発明の板ガラス製造方法では、ガラスリボンに硫酸塩の疵防止用保護層を形成する際の効率を向上させるために、ガラス原料にアルカリ金属酸化物を６００～２０００モルｐｐｍ含有させることが好ましい。
　本発明では、ガラス原料にアルカリ金属酸化物を６００モルｐｐｍ以上含有させることにより、疵防止用保護層をガラスリボンに形成する際の効率が向上する。その理由は以下の通り。
　無アルカリガラスはアルカリ金属酸化物を含有していないため、高温のガラスリボンをＳＯ２ガス雰囲気中に晒しても、アルカリ金属硫酸塩の析出による疵防止用保護層を形成することができない。アルカリ土類金属酸化物を多く含む組成の無アルカリガラスでは、高温でＳＯ２ガス雰囲気に晒した場合、アルカリ金属硫酸塩のかわりにアルカリ土類金属の硫酸塩が析出するが、その析出量は少なく、疵防止用保護層を形成するには、より高温、あるいはより長時間、あるいはより高濃度のＳＯ２ガスに晒す必要がある。しかしながら、本発明者らは、ガラス原料にアルカリ金属酸化物を微量添加することにより、アルカリ土類金属硫酸塩の析出効果が増し、疵防止用保護層をガラスリボンに形成する際の効率が向上することを見出した。
　ここで、アルカリ金属酸化物を含有量が高くなると、アルカリ金属イオンが薄膜中に拡散して膜特性を劣化させるため、各種ディスプレイ用基板ガラスとしての使用時に問題となるが、ガラス組成中のアルカリ金属酸化物を含有量が２０００モルｐｐｍ以下であれば、このような問題を生じることがない。より好ましくは１５００モルｐｐｍ以下、さらに好ましくは１３００モルｐｐｍ以下、特に好ましくは１０００モルｐｐｍ以下である。
　本発明に用いるガラス原料は、アルカリ金属酸化物を好ましくは１５００モルｐｐｍ以下、より好ましくは１３００モルｐｐｍ以下、さらに好ましくは１０００モルｐｐｍ以下含有し、さらには７００～９００モルｐｐｍ含有することが好ましく、７００～８００モルｐｐｍ含有することがより好ましい。
　また、アルカリ金属酸化物としては、Ｎａ２Ｏ、Ｋ２Ｏが、疵防止用保護層をガラスリボンに形成する際の効率を向上させる効果と、原料コストと、のバランスの観点から好ましく、Ｎａ２Ｏがより好ましい。 In the method for producing sheet glass of the present invention, it is preferable to contain 600 to 2000 mol ppm of an alkali metal oxide in the glass raw material in order to improve the efficiency when forming a protective layer for preventing sulfate wrinkles on the glass ribbon.
In this invention, the efficiency at the time of forming the protective layer for wrinkle prevention in a glass ribbon improves by making a glass raw material contain 600 molppm or more of alkali metal oxides. The reason is as follows.
Since alkali-free glass does not contain an alkali metal oxide, even if a high-temperature glass ribbon is exposed to the SO 2 gas atmosphere, a protective layer for preventing wrinkles due to precipitation of alkali metal sulfate cannot be formed. In an alkali-free glass having a composition containing a large amount of alkaline earth metal oxides, when exposed to an SO 2 gas atmosphere at a high temperature, alkaline earth metal sulfates are precipitated instead of alkali metal sulfates. In order to form a protective layer for preventing wrinkles, it is necessary to expose the SO 2 gas to a higher temperature, a longer time, or a higher concentration. However, the present inventors added a small amount of alkali metal oxide to the glass raw material, thereby increasing the precipitation effect of alkaline earth metal sulfate and improving the efficiency when forming the protective layer for preventing wrinkles on the glass ribbon. I found out.
Here, when the content of the alkali metal oxide is increased, alkali metal ions diffuse into the thin film and deteriorate the film characteristics. This causes a problem when used as a substrate glass for various displays. If the content of the metal oxide is 2000 mol ppm or less, such a problem will not occur. More preferably, it is 1500 mol ppm or less, More preferably, it is 1300 mol ppm or less, Most preferably, it is 1000 mol ppm or less.
The glass raw material used in the present invention preferably contains an alkali metal oxide of 1500 mol ppm or less, more preferably 1300 mol ppm or less, more preferably 1000 mol ppm or less, and more preferably 700 to 900 mol ppm. More preferably 700 to 800 mol ppm.
Further, as the alkali metal oxide, Na 2 O and K 2 O are preferable from the viewpoint of the balance between the effect of improving the efficiency when forming the protective layer for preventing wrinkles on the glass ribbon and the raw material cost, and Na 2 O is more preferable.
　なお、パネル製造時にガラス表面に設ける金属ないし酸化物薄膜の特性劣化を生じさせないために、ガラス原料はＰ２Ｏ５を実質的に含有しないことが好ましい。さらに、ガラスのリサイクルを容易にするため、ガラス原料はＰｂＯ、Ａｓ２Ｏ３、Ｓｂ２Ｏ３は実質的に含有しないことが好ましい。 In order to prevent the deterioration of the properties of the metal or oxide thin film provided on the glass surface during panel manufacture, it is preferable that the glass raw material does not substantially contain P 2 O 5 . Furthermore, in order to facilitate recycling of the glass, it is preferable that the glass raw material does not substantially contain PbO, As 2 O 3 , or Sb 2 O 3 .
　ガラスの溶解性、清澄性、成形性を改善するため、ガラス原料にはＺｎＯ、Ｆｅ２Ｏ３、ＳＯ３、Ｆ、Ｃｌ、ＳｎＯ２を総量で５％以下添加できる。 In order to improve the solubility, clarity, and moldability of the glass, ZnO, Fe 2 O 3 , SO 3 , F, Cl, SnO 2 can be added to the glass raw material in a total amount of 5% or less.
　上記ガラス組成１，２は、比較的溶解性が低いため、各成分の原料として下記を用いることが好ましい。 Since the glass compositions 1 and 2 have relatively low solubility, it is preferable to use the following as raw materials for each component.
（珪素源）
　ＳｉＯ２の珪素源としては珪砂を用いることができるが、メディアン粒径Ｄ５０が２０μｍ～２７μｍ、粒径２μｍ以下の粒子の割合が０．３体積％以下、かつ粒径１００μｍ以上の粒子の割合が２．５体積％以下の珪砂を用いることが、珪砂の凝集を抑えて溶解させることができるので、珪砂の溶解が容易になり、泡が少なく、均質性、平坦度が高い板ガラスが得られることから好ましい。 (Silicon source)
Silica sand can be used as the silicon source of SiO 2 , but the proportion of particles having a median particle size D 50 of 20 μm to 27 μm, a particle size of 2 μm or less is 0.3% by volume or less, and the particle size is 100 μm or more. Using 2.5% by volume or less of silica sand can suppress the agglomeration of the silica sand and dissolve it, so that the silica sand can be easily dissolved, and there is less foam, and a plate glass with high homogeneity and flatness can be obtained. This is preferable.
　なお、本明細書における「粒径」とは珪砂の球相当径（本発明では一次粒径の意）であって、具体的にはレーザー回折／散乱法によって計測された粉体の粒度分布における粒径をいう。
　また、本明細書における「メディアン粒径Ｄ５０」とは、レーザー回折法によって計測された粉体の粒度分布において、ある粒径より大きい粒子の体積頻度が、全粉体のそれの５０％を占める粒子径をいう。言い換えると、レーザー回折法によって計測された粉体の粒度分布において、累積頻度が５０％のときの粒子径をいう。
　また、本明細書における「粒径２μｍ以下の粒子の割合」及び「粒径１００μｍ以上の粒子の割合」は、例えば、レーザー回折／散乱法によって粒度分布を計測することにより測定される。 The “particle size” in this specification is the equivalent sphere diameter of silica sand (meaning the primary particle size in the present invention), and specifically, in the particle size distribution of the powder measured by the laser diffraction / scattering method. Refers to particle size.
Further, in this specification, “median particle size D 50 ” means that the volume frequency of particles larger than a certain particle size is 50% of the total powder in the particle size distribution of the powder measured by the laser diffraction method. The particle diameter occupied. In other words, it refers to the particle diameter when the cumulative frequency is 50% in the particle size distribution of the powder measured by the laser diffraction method.
Further, the “ratio of particles having a particle diameter of 2 μm or less” and “ratio of particles having a particle diameter of 100 μm or more” in this specification are measured by measuring the particle size distribution by a laser diffraction / scattering method, for example.
　珪砂のメディアン粒径Ｄ５０が２５μｍ以下であれば、珪砂の溶解がより容易になるので、より好ましい。
　また、珪砂における粒径１００μｍ以上の粒子の割合は、０％であることが珪砂の溶解がより容易になるので特に好ましい。 If the median particle diameter D 50 of silica sand is 25 μm or less, it is more preferable because dissolution of silica sand becomes easier.
Further, the ratio of the particles having a particle diameter of 100 μm or more in the silica sand is particularly preferably 0% because the silica sand is more easily dissolved.
（アルカリ土類金属源）
　アルカリ土類金属源としては、アルカリ土類金属化合物を用いることができる。ここでアルカリ土類金属化合物の具体例としては、ＭｇＣＯ３、ＣａＣＯ３、ＢａＣＯ３、ＳｒＣＯ３、（Ｍｇ，Ｃａ）ＣＯ３（ドロマイト）等の炭酸塩や、ＭｇＯ、ＣａＯ、ＢａＯ、ＳｒＯ等の酸化物や、Ｍｇ（ＯＨ）２、Ｃａ（ＯＨ）２、Ｂａ（ＯＨ）２、Ｓｒ（ＯＨ）２等の水酸化物を例示できるが、アルカリ土類金属源の一部または全部にアルカリ土類金属の水酸化物を含有させることが、ガラス原料の溶解時のＳｉＯ２成分の未溶解量が低下するので好ましい。珪砂中に含まれるＳｉＯ２成分の未溶解量が増大すると、この未溶解のＳｉＯ２が、溶融ガラス中に泡が発生した際にこの泡に取り込まれて溶融ガラスの表層近くに集まる。これにより、溶融ガラスの表層と表層以外の部分との間においてＳｉＯ２の組成比に差が生じて、ガラスの均質性が低下するとともに平坦性も低下する。 (Alkaline earth metal source)
An alkaline earth metal compound can be used as the alkaline earth metal source. Specific examples of the alkaline earth metal compound include carbonates such as MgCO 3 , CaCO 3 , BaCO 3 , SrCO 3 , (Mg, Ca) CO 3 (dolomite), MgO, CaO, BaO, SrO and the like. Oxides and hydroxides such as Mg (OH) 2 , Ca (OH) 2 , Ba (OH) 2 , and Sr (OH) 2 can be exemplified. It is preferable to contain a hydroxide of a similar metal since the undissolved amount of the SiO 2 component at the time of melting the glass raw material is reduced. When the undissolved amount of the SiO 2 component contained in the silica sand increases, the undissolved SiO 2 is taken into the bubbles when the bubbles are generated in the molten glass and gathers near the surface layer of the molten glass. As a result, a difference in the composition ratio of SiO 2 occurs between the surface layer of the molten glass and the portion other than the surface layer, so that the homogeneity of the glass is lowered and the flatness is also lowered.
　アルカリ土類金属の水酸化物の含有量は、アルカリ土類金属源１００質量モル％（ＭＯ換算。但しＭはアルカリ土類金属元素である。）のうち、好ましくは１５～１００モル％（ＭＯ換算）、より好ましくは３０～１００モル％（ＭＯ換算）であり、さらに好ましくは６０～１００モル％（ＭＯ換算）であることが、ガラス原料の溶解時のＳｉＯ２成分の未溶解量が低下するのでより好ましい。
　アルカリ土類金属源中の水酸化物のモル比が増加するにつれて、ガラス原料の溶解時のＳｉＯ２成分の未溶解量が低下するので、上記水酸化物のモル比は高ければ高いほどよい。 The content of the alkaline earth metal hydroxide is preferably 15 to 100 mol% (MO conversion in terms of MO, where M is an alkaline earth metal element). Conversion), more preferably 30 to 100 mol% (MO conversion), and even more preferably 60 to 100 mol% (MO conversion), the undissolved amount of the SiO 2 component at the time of melting the glass raw material is reduced. Therefore, it is more preferable.
As the molar ratio of the hydroxide in the alkaline earth metal source increases, the undissolved amount of the SiO 2 component at the time of melting the glass raw material decreases, so the higher the molar ratio of the hydroxide, the better.
　アルカリ土類金属源として、具体的には、アルカリ土類金属の水酸化物と炭酸塩との混合物、アルカリ土類金属の水酸化物単独、などを用いることができる。炭酸塩としては、ＭｇＣＯ３、ＣａＣＯ３及び（Ｍｇ，Ｃａ）（ＣＯ３）２（ドロマイト）のいずれか１種以上を用いることが好ましい。またアルカリ土類金属の水酸化物としては、Ｍｇ（ＯＨ）２またはＣａ（ＯＨ）２の少なくとも一方を用いることが好ましく、特にＭｇ（ＯＨ）２を用いることが好ましい。 Specifically, as the alkaline earth metal source, a mixture of an alkaline earth metal hydroxide and a carbonate, an alkaline earth metal hydroxide alone, or the like can be used. As the carbonate, it is preferable to use at least one of MgCO 3 , CaCO 3 and (Mg, Ca) (CO 3 ) 2 (dolomite). As the alkaline earth metal hydroxide, it is preferable to use at least one of Mg (OH) 2 and Ca (OH) 2 , and it is particularly preferable to use Mg (OH) 2 .
（ホウ素源）
　上記ガラス組成１，２がＢ２Ｏ３を含有する場合、Ｂ２Ｏ３のホウ素源としては、ホウ素化合物を用いることができる。ここでホウ素化合物の具体例としては、オルトホウ酸（Ｈ３ＢＯ３）、メタホウ酸（ＨＢＯ２）、四ホウ酸（Ｈ２Ｂ４Ｏ７）、無水ホウ酸（Ｂ２Ｏ３）等が挙げられる。通常の無アルカリガラスの製造においては、安価で、入手しやすい点から、オルトホウ酸が用いられる。 (Boron source)
If the glass composition 1 contains B 2 O 3, as the boron source B 2 O 3, can be used boron compound. Here, specific examples of the boron compound include orthoboric acid (H 3 BO 3 ), metaboric acid (HBO 2 ), tetraboric acid (H 2 B 4 O 7 ), and anhydrous boric acid (B 2 O 3 ). It is done. In the production of ordinary alkali-free glass, orthoboric acid is used because it is inexpensive and easily available.
　本発明においては、ホウ素源として、無水ホウ酸を、ホウ素源１００質量％（Ｂ２Ｏ３換算）のうち、１０～１００質量％（Ｂ２Ｏ３換算）含有するものを用いることが好ましい。無水ホウ酸を１０質量％以上とすることにより、ガラス原料の凝集が抑えられ、泡の低減効果、均質性、平坦度の向上効果が得られる。無水ホウ酸は、２０～１００質量％がより好ましく、４０～１００質量％がさらに好ましい。
　無水ホウ酸以外のホウ素化合物としては、安価で、入手しやすい点から、オルトホウ酸が好ましい。 In the present invention, it is preferable to use, as the boron source, boric anhydride containing 10 to 100% by mass (in terms of B 2 O 3 ) out of 100% by mass of boron source (in terms of B 2 O 3 ). By setting the boric anhydride to 10% by mass or more, aggregation of the glass raw material is suppressed, and an effect of reducing bubbles, homogeneity, and improving flatness can be obtained. The boric anhydride is more preferably 20 to 100% by mass, and further preferably 40 to 100% by mass.
As the boron compound other than boric anhydride, orthoboric acid is preferable because it is inexpensive and easily available.
　板ガラスの製造は、たとえば、以下の手順で実施する。
　各成分の原料を目標成分になるように調合し、これを溶解炉に連続的に投入し、１５００～１８００℃に加熱して溶融する。この溶融ガラスを成形装置にて、所定の板厚の板状のガラスリボンに成形し、このガラスリボンを徐冷後切断することによって板ガラスを得ることができる。
　本発明では、フロート法にて板状のガラスリボンに成形することが好ましい。 Manufacture of plate glass is performed in the following procedure, for example.
The raw materials of each component are prepared so as to become target components, which are continuously charged into a melting furnace, heated to 1500-1800 ° C. and melted. A plate glass can be obtained by forming this molten glass into a plate-like glass ribbon having a predetermined plate thickness using a molding apparatus, and then cooling the glass ribbon after slow cooling.
In this invention, it is preferable to shape | mold into a plate-shaped glass ribbon by the float glass process.
　本発明では、徐冷炉内において、ガラスリボンに対して、以下に示す条件を満たすように亜硫酸（ＳＯ２）ガスを供給する。
　無アルカリガラスの歪点をＴｓｔ（℃）とするとき、Ｔｓｔ＋７０℃～Ｔｓｔ－５０℃の温度域で、ガラスリボンの下面の直下の雰囲気濃度が５００～２００００ｐｐｍとなる時間が３０秒以上となるように、ＳＯ２ガスを供給する。雰囲気濃度が５００ｐｐｍ未満だと、アルカリ土類金属の硫酸塩の析出量が少なくなるおそれがある。より好ましくは１０００ｐｐｍ以上である。雰囲気濃度が２００００ｐｐｍ超だと、設備の腐食が問題となるおそれがある。より好ましくは１００００ｐｐｍ以下、さらに好ましくは５０００ｐｐｍ以下である。また、３０秒未満だとアルカリ土類金属の硫酸塩の析出量が少なくなるおそれがある。より好ましくは１分以上である。
　本発明では、ガラスリボンの下面からＳＯ２ガスを供給することが好ましい。下面からＳＯ２ガスを供給することにより、比重の重いＳＯ２ガスは下面のみにアルカリ土類金属の硫酸塩を析出させ、ガスの拡散を防ぎ、アルカリ土類金属の硫酸塩の析出効果を上げることができる。
　本発明では、水蒸気露点が３０℃以上の雰囲気にてガラスリボンをＳＯ２ガスと接触するようにすることが好ましい。水蒸気露点が低いと、アルカリ土類金属の硫酸塩の析出効果を上げらないおそれがある。より好ましくは４０℃以上、さらに好ましくは５０℃以上である。 In the present invention, sulfur dioxide (SO 2 ) gas is supplied to the glass ribbon so as to satisfy the following conditions in the slow cooling furnace.
When the strain point of the alkali-free glass is T st (° C.), the time during which the atmospheric concentration immediately below the bottom surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st −50 ° C. is 30 seconds. The SO 2 gas is supplied so as to achieve the above. If the atmospheric concentration is less than 500 ppm, the precipitation amount of alkaline earth metal sulfate may be reduced. More preferably, it is 1000 ppm or more. If the atmospheric concentration exceeds 20000 ppm, corrosion of the equipment may become a problem. More preferably, it is 10,000 ppm or less, More preferably, it is 5000 ppm or less. Moreover, when it is less than 30 seconds, there exists a possibility that the precipitation amount of an alkaline-earth metal sulfate may decrease. More preferably, it is 1 minute or more.
In the present invention, it is preferable to supply the SO 2 gas from the lower surface of the glass ribbon. By supplying SO 2 gas from the lower surface, the heavy specific gravity SO 2 gas precipitates alkaline earth metal sulfate only on the lower surface, prevents gas diffusion and increases the alkaline earth metal sulfate precipitation effect. be able to.
In the present invention, the glass ribbon is preferably brought into contact with the SO 2 gas in an atmosphere having a water vapor dew point of 30 ° C. or higher. If the water vapor dew point is low, the precipitation effect of alkaline earth metal sulfate may not be improved. More preferably, it is 40 degreeC or more, More preferably, it is 50 degreeC or more.
　本発明のガラスは、歪点が７１０℃以上であり、パネル製造時の熱収縮を抑えられる。また、ｐ－Ｓｉ　ＴＦＴの製造方法として固相結晶化法を適用することができる。また本発明の製造方法では、より高い温度でＳＯ２ガスを供給することができるので、アルカリ土類金属の硫酸塩からなる疵防止用保護層の形成効率がよい。歪点は、より好ましくは７１５℃以上、さらに好ましくは７２０℃以上である。特に好ましくは７３５℃以上である。歪点が７３５℃以上であると、高歪点用途（例えば、有機ＥＬ用のディスプレイ用基板または照明用基板、あるいは板厚１００μｍ以下の薄板のディスプレイ用基板または照明用基板）に適している。
　板厚１００μｍ以下の板ガラスの成形では、成形時の引き出し速度が速くなる傾向があるため、ガラスの仮想温度が上昇し、ガラスのコンパクションが増大しやすい。この場合、高歪点ガラスであると、コンパクションを抑制することができる。 The glass of the present invention has a strain point of 710 ° C. or higher, and can suppress thermal shrinkage during panel production. Further, a solid phase crystallization method can be applied as a method for manufacturing a p-Si TFT. In the production method of the present invention, it is possible to supply the SO 2 gas at a higher temperature, it is formed efficiency flaw preventing protection layer consisting of alkaline earth metal sulfates. The strain point is more preferably 715 ° C or higher, and further preferably 720 ° C or higher. Especially preferably, it is 735 degreeC or more. When the strain point is 735 ° C. or higher, it is suitable for high strain point applications (for example, an organic EL display substrate or illumination substrate, or a thin display substrate or illumination substrate having a thickness of 100 μm or less).
In the formation of a plate glass having a plate thickness of 100 μm or less, since the drawing speed at the time of forming tends to increase, the fictive temperature of the glass rises and the glass compaction tends to increase. In this case, compaction can be suppressed when the glass is a high strain point glass.
　但し、ガラスの歪点が高過ぎると、それに応じて成形装置の温度を高くする必要があり、成形装置の寿命が低下する。このため、本発明の板ガラスは歪点が７５０℃以下である。 However, if the strain point of the glass is too high, it is necessary to increase the temperature of the molding apparatus accordingly, and the life of the molding apparatus is reduced. For this reason, the strain point of the plate glass of the present invention is 750 ° C. or less.
　また本発明のガラスは、歪点と同様の理由で、ガラス転移点が好ましくは７６０℃以上であり、より好ましくは７７０℃以上であり、さらに好ましくは７８０℃以上である。 The glass of the present invention has a glass transition point of preferably 760 ° C. or higher, more preferably 770 ° C. or higher, and further preferably 780 ° C. or higher for the same reason as the strain point.
　また本発明のガラスは、５０～３００℃での平均熱膨張係数が３０×１０-７～４３×１０-７／℃であり、耐熱衝撃性が大きく、パネル製造時の生産性を高くできる。本発明のガラスにおいて、５０～３００℃での平均熱膨張係数が３５×１０-７～４０×１０-７／℃であることが好ましい。 In addition, the glass of the present invention has an average coefficient of thermal expansion at 50 to 300 ° C. of 30 × 10 −7 to 43 × 10 −7 / ° C., has high thermal shock resistance, and can increase productivity during panel manufacture. In the glass of the present invention, the average thermal expansion coefficient at 50 to 300 ° C. is preferably 35 × 10 −7 to 40 × 10 −7 / ° C.
　さらに、本発明のガラスは、比重が好ましくは２．６５以下であり、より好ましくは２．６４以下であり、さらに好ましくは２．６２以下である。 Furthermore, the specific gravity of the glass of the present invention is preferably 2.65 or less, more preferably 2.64 or less, and further preferably 2.62 or less.
　また、本発明のガラスは、粘度ηが１０２ポイズ（ｄＰａ・ｓ）となる温度Ｔ２が１７１０℃以下であり、好ましくは１７１０℃未満、より好ましくは１７００℃以下、さらに好ましくは１６９０℃以下になっているため、溶解が比較的容易である。 In the glass of the present invention, the temperature T 2 at which the viscosity η becomes 10 2 poise (dPa · s) is 1710 ° C. or less, preferably less than 1710 ° C., more preferably 1700 ° C. or less, and further preferably 1690 ° C. or less. Therefore, dissolution is relatively easy.
　さらに、本発明のガラスは粘度ηが１０４ポイズとなる温度Ｔ４が１３２０℃以下、好ましくは１３１５℃以下、より好ましくは１３１０℃以下、さらに好ましくは１３０５℃以下であり、フロート成形に適している。
　また、本発明のガラスは失透温度が、１３５０℃以下であることがフロート法による成形が容易となることから好ましい。好ましくは１３４０℃以下、より好ましくは１３３０℃以下である。
　本明細書における失透温度は、白金製の皿に粉砕されたガラス粒子を入れ、一定温度に制御された電気炉中で１７時間熱処理を行い、熱処理後の光学顕微鏡観察によって、ガラスの表面及び内部に結晶が析出する最高温度と結晶が析出しない最低温度との平均値である。 Further, the glass of the present invention has a temperature T 4 at which the viscosity η becomes 10 4 poise is 1320 ° C. or less, preferably 1315 ° C. or less, more preferably 1310 ° C. or less, and further preferably 1305 ° C. or less, which is suitable for float molding. Yes.
In addition, the glass of the present invention preferably has a devitrification temperature of 1350 ° C. or lower because molding by the float method is easy. Preferably it is 1340 degrees C or less, More preferably, it is 1330 degrees C or less.
In this specification, the devitrification temperature is obtained by putting crushed glass particles in a platinum dish and performing heat treatment for 17 hours in an electric furnace controlled at a constant temperature. It is an average value of the maximum temperature at which crystals are deposited inside and the minimum temperature at which crystals are not deposited.
　また、本発明のガラスは、ヤング率が８４ＧＰａ以上、さらには８６ＧＰａ以上、さらには８８ＧＰａ以上、さらには９０ＧＰａ以上が好ましい。 Further, the glass of the present invention preferably has a Young's modulus of 84 GPa or more, more preferably 86 GPa or more, further 88 GPa or more, and further 90 GPa or more.
　また、本発明のガラスは、光弾性定数が３１ｎｍ／ＭＰａ／ｃｍ以下であることが好ましい。
　液晶ディスプレイパネル製造工程や液晶ディスプレイ装置使用時に発生した応力によってガラス基板が複屈折性を有することにより、黒の表示がグレーになり、液晶ディスプレイのコントラストが低下する現象が認められることがある。光弾性定数を３１ｎｍ／ＭＰａ／ｃｍ以下とすることにより、この現象を小さく抑えることができる。好ましくは３０ｎｍ／ＭＰａ／ｃｍ以下、より好ましくは２９ｎｍ／ＭＰａ／ｃｍ以下、さらに好ましくは２８．５ｎｍ／ＭＰａ／ｃｍ以下、特に好ましくは２８ｎｍ／ＭＰａ／ｃｍ以下である。
　また、本発明のガラスは、他の物性確保の容易性を考慮すると、光弾性定数が２５ｎｍ／ＭＰａ／ｃｍ以下であることが好ましい。
　なお、光弾性定数は円盤圧縮法により測定できる。 The glass of the present invention preferably has a photoelastic constant of 31 nm / MPa / cm or less.
Due to the birefringence of the glass substrate due to stress generated during the manufacturing process of the liquid crystal display panel and the liquid crystal display device, a phenomenon in which the black display becomes gray and the contrast of the liquid crystal display decreases may be observed. By setting the photoelastic constant to 31 nm / MPa / cm or less, this phenomenon can be suppressed small. Preferably it is 30 nm / MPa / cm or less, More preferably, it is 29 nm / MPa / cm or less, More preferably, it is 28.5 nm / MPa / cm or less, Most preferably, it is 28 nm / MPa / cm or less.
In addition, the glass of the present invention preferably has a photoelastic constant of 25 nm / MPa / cm or less, considering the ease of securing other physical properties.
The photoelastic constant can be measured by a disk compression method.
　また、本発明のガラスは、比誘電率が５．６以上であることが好ましい。
　日本国特開２０１１－７００９２号公報に記載されているような、インセル型のタッチパネル（液晶ディスプレイパネル内にタッチセンサを内蔵したもの）の場合、タッチセンサのセンシング感度の向上、駆動電圧の低下、省電力化の観点から、ガラス基板の比誘電率が高いほうがよい。比誘電率を５．６以上とすることにより、タッチセンサのセンシング感度が向上する。好ましくは５．８以上、より好ましくは６．０以上、さらに好ましくは６．２以上、特に好ましくは６．４以上である。
　なお、比誘電率はＪＩＳ　Ｃ－２１４１に記載の方法で測定できる。 The glass of the present invention preferably has a relative dielectric constant of 5.6 or more.
In the case of an in-cell type touch panel (in which a touch sensor is built in a liquid crystal display panel) as described in Japanese Unexamined Patent Publication No. 2011-70092, the sensing sensitivity of the touch sensor is improved, the driving voltage is reduced, From the viewpoint of power saving, it is better that the glass substrate has a higher relative dielectric constant. By setting the relative dielectric constant to 5.6 or more, the sensing sensitivity of the touch sensor is improved. Preferably it is 5.8 or more, More preferably, it is 6.0 or more, More preferably, it is 6.2 or more, Most preferably, it is 6.4 or more.
The relative dielectric constant can be measured by the method described in JIS C-2141.
（実施例１、比較例１，２）
　各成分の原料を、表１に示す目標組成になるように調合し、連続溶融窯にて溶解を行い、フロート法にて板成形を行った。このとき用いた原料中のアルカリ金属酸化物の含有量としてＮａ２Ｏの含有量、使用した原料中の珪砂の粒度として、メディアン粒径Ｄ５０、粒径２μｍ以下の粒子の割合、および、粒径１００μｍ以上の粒子の割合をあわせて表１に示す。また、アルカリ土類金属における水酸化物原料のモル比率（ＭＯ換算）もあわせて表１に示す。
　得られたガラスを鏡面研磨後、表２に示す熱処理温度、熱処理時間、ＳＯ２ガス濃度、水蒸気露点にてＳＯ２ガス雰囲気中で熱処理を行った。得られたガラスの表面の硫酸塩析出状況は、蛍光Ｘ線による表面Ｓ濃度（質量％）として測定した。ガラスの歪点、表面Ｓ濃度（質量％）もあわせて表２に示す。 (Example 1, Comparative Examples 1 and 2)
The raw material of each component was prepared so that it might become the target composition shown in Table 1, it melt | dissolved in the continuous melting kiln, and plate forming was performed by the float process. As the content of the alkali metal oxide in the raw material used at this time, the content of Na 2 O, the particle size of the silica sand in the used raw material, the median particle size D 50 , the proportion of particles having a particle size of 2 μm or less, and Table 1 shows the ratio of particles having a diameter of 100 μm or more. Table 1 also shows the molar ratio (in terms of MO) of the hydroxide raw material in the alkaline earth metal.
The obtained glass was mirror-polished and then heat-treated in an SO 2 gas atmosphere at the heat treatment temperature, heat treatment time, SO 2 gas concentration and water vapor dew point shown in Table 2. The sulfate precipitation state on the surface of the obtained glass was measured as the surface S concentration (mass%) by fluorescent X-rays. Table 2 also shows the strain point and surface S concentration (% by mass) of the glass.
［蛍光Ｘ線による表面Ｓ濃度の測定方法］
　硫酸塩が析出されたガラス試料について、表３に示す条件にて、φ１０ｍｍのマスクにてＳ－ｋα線のカウント数を測定する。Ｓ濃度が既知のガラスを鏡面研磨した後、表３に示す条件にてφ１０ｍｍのマスクにてＳ－ｋα線のカウント数を測定し、Ｓ－ｋα線のカウント数とＳ濃度（質量％）の相関関係を得る。得られた相関関係を用いることで、硫酸塩が析出されたガラス試料のＳ－ｋα線カウント数をＳ濃度（質量％）へ換算する。表面Ｓ濃度は、０．１５質量％以上が好ましく、０．２質量％以上がより好ましい。 [Measurement method of surface S concentration by fluorescent X-ray]
With respect to the glass sample on which the sulfate is deposited, the number of counts of S-kα rays is measured using a φ10 mm mask under the conditions shown in Table 3. After mirror-polishing glass with a known S concentration, the count number of S-kα rays was measured with a φ10 mm mask under the conditions shown in Table 3, and the S-kα ray count number and S concentration (mass%) Get correlation. By using the obtained correlation, the Skα ray count number of the glass sample on which the sulfate salt is deposited is converted into the S concentration (mass%). The surface S concentration is preferably 0.15% by mass or more, and more preferably 0.2% by mass or more.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
（実施例２～４）
　各成分の原料を、表４に示す目標組成になるように調合し、白金坩堝を用いて１５５０℃の温度で１時間溶解した。溶解後、カーボン板状に流し出し、ガラス転移点＋３０℃にて１時間保持後、１℃／分で冷却を行い、徐冷を行った。このとき用いた原料中のアルカリ金属酸化物の含有量としてＮａ２Ｏの含有量、使用した原料中の珪砂の粒度として、メディアン粒径Ｄ５０、粒径２μｍ以下の粒子の割合、および、粒径１００μｍ以上の粒子の割合をあわせて表４に示す。また、アルカリ土類金属における水酸化物原料のモル比率（ＭＯ換算）もあわせて表４に示す。
　得られたガラスを切断し、鏡面研磨後、表５に示す熱処理温度、熱処理時間、ＳＯ２ガス濃度、水蒸気露点にてＳＯ２ガス雰囲気中で熱処理を行った。得られたガラスの表面の硫酸塩析出状況は、蛍光Ｘ線による表面Ｓ濃度（質量％）として測定した。ガラスの歪点、表面Ｓ濃度（質量％）もあわせて表５に示す。 (Examples 2 to 4)
The raw materials of each component were prepared so as to have the target composition shown in Table 4, and were melted at a temperature of 1550 ° C. for 1 hour using a platinum crucible. After dissolution, it was poured out into a carbon plate, held at glass transition point + 30 ° C. for 1 hour, cooled at 1 ° C./min, and gradually cooled. As the content of the alkali metal oxide in the raw material used at this time, the content of Na 2 O, the particle size of the silica sand in the used raw material, the median particle size D 50 , the proportion of particles having a particle size of 2 μm or less, and Table 4 shows the ratio of particles having a diameter of 100 μm or more. Table 4 also shows the molar ratio (MO conversion) of the hydroxide raw material in the alkaline earth metal.
The obtained glass was cut, and after mirror polishing, heat treatment was performed in an SO 2 gas atmosphere at the heat treatment temperature, heat treatment time, SO 2 gas concentration, and water vapor dew point shown in Table 5. The sulfate precipitation state on the surface of the obtained glass was measured as the surface S concentration (mass%) by fluorescent X-rays. Table 5 also shows the strain point and surface S concentration (mass%) of the glass.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　本発明を詳細にまた特定の実施態様を参照して説明したが、本発明の精神と範囲を逸脱することなく、様々な修正や変更を加えることができることは、当業者にとって明らかである。
　本出願は、２０１２年５月１６日出願の日本特許出願２０１２－１１２２２６に基づくものであり、その内容はここに参照として取り込まれる。 Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2012-112226 filed on May 16, 2012, the contents of which are incorporated herein by reference.
　本発明によって得られる板ガラスは、歪点が高く、ディスプレイ用基板、フォトマスク用基板等の用途に好適である。また、太陽電池用基板等の用途にも好適である。 The plate glass obtained by the present invention has a high strain point and is suitable for uses such as a display substrate and a photomask substrate. Moreover, it is suitable also for uses, such as a board | substrate for solar cells.

Claims (7)

  1. 　ガラス原料を溶解し溶融ガラスとし、該溶融ガラスを成形装置にて板状のガラスリボンに成形した後、該ガラスリボンを徐冷装置にて徐冷する板ガラス製造方法であって、
    　前記板ガラスが下記の無アルカリガラスからなり、
    　前記無アルカリガラスの歪点をＴｓｔ（℃）とするとき、Ｔｓｔ＋７０℃～Ｔｓｔ－５０℃の温度域で、前記ガラスリボンの下面の直下の雰囲気濃度が５００～２００００ｐｐｍとなる時間が３０秒以上となるように、ＳＯ２ガスを供給する板ガラス製造方法。
    　歪点が７１０～７５０℃であって、５０～３００℃での平均熱膨張係数が３０×１０-７～４３×１０-７／℃であって、ガラス粘度が１０２ｄＰａ・ｓとなる温度Ｔ２が１７１０℃以下であって、ガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４が１３２０℃以下であって、
    酸化物基準のモル％表示で
    ＳｉＯ２ 　　　　　　 ６６～７０、
    Ａｌ２Ｏ３　　　　　　１２～１５、
    Ｂ２Ｏ３　　　　　　　　０～１．５、
    ＭｇＯ 　　　　　　　 ９．５超１３以下、
    ＣａＯ 　　　　　　　 ４～９、
    ＳｒＯ　　　　　　　　０．５～４．５、
    ＢａＯ 　　　　　　　 ０～１、
    ＺｒＯ２　　　　　　　 ０～２、を含有し、
    ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１７～２１であり、
    ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．４０以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上である無アルカリガラス。     A glass glass manufacturing method in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a molding device, and then the glass ribbon is gradually cooled with a slow cooling device,
    The plate glass is made of the following alkali-free glass,
    When the strain point of the alkali-free glass is T st (° C.), the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st −50 ° C. A plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer.
    Temperature at which the strain point is 710 to 750 ° C., the average coefficient of thermal expansion at 50 to 300 ° C. is 30 × 10 −7 to 43 × 10 −7 / ° C., and the glass viscosity is 10 2 dPa · s. T 2 is 1710 ° C. or lower, and the temperature T 4 at which the glass viscosity is 10 4 dPa · s is 1320 ° C. or lower,
    SiO 2 66 to 70 in terms of mol% based on oxide,
    Al 2 O 3 12-15,
    B 2 O 3 0-1.5,
    MgO more than 9.5 and 13 or less,
    CaO 4-9,
    SrO 0.5-4.5,
    BaO 0 ~ 1,
    ZrO 2 0-2,
    MgO + CaO + SrO + BaO is 17-21,
    An alkali-free glass in which MgO / (MgO + CaO + SrO + BaO) is 0.40 or more, MgO / (MgO + CaO) is 0.40 or more, and MgO / (MgO + SrO) is 0.60 or more.
  2. 　ガラス原料を溶解し溶融ガラスとし、該溶融ガラスを成形装置にて板状のガラスリボンに成形した後、該ガラスリボンを徐冷装置にて徐冷する板ガラス製造方法であって、
    　前記板ガラスが下記の無アルカリガラスからなり、
    　前記無アルカリガラスの歪点をＴｓｔ（℃）とするとき、Ｔｓｔ＋７０℃～Ｔｓｔ－５０℃の温度域で、前記ガラスリボンの下面の直下の雰囲気濃度が５００～２００００ｐｐｍとなる時間が３０秒以上となるように、ＳＯ２ガスを供給する板ガラス製造方法。
    　歪点が７１０～７５０℃であって、５０～３００℃での平均熱膨張係数が３０×１０-７～４３×１０-７／℃であって、ガラス粘度が１０２ｄＰａ・ｓとなる温度Ｔ２が１７１０℃以下であって、ガラス粘度が１０４ｄＰａ・ｓとなる温度Ｔ４が１３２０℃以下であって、
    酸化物基準のモル％表示で
    ＳｉＯ２ 　　　　　　 ６６～７０、
    Ａｌ２Ｏ３　　　　　　１２～１５、
    Ｂ２Ｏ３　　　　　　　　０～１．５、
    ＭｇＯ 　　　　　　　 ５～９．５、
    ＣａＯ 　　　　　　　 ４～１１、
    ＳｒＯ　　　　　　　　０．５～４．５、
    ＢａＯ 　　　　　　　 ０～１、
    ＺｒＯ２　　　　　　　 ０～２、を含有し、
    ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ が１８．２超２１以下であり、
    ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ）が０．２５以上であり、ＭｇＯ／（ＭｇＯ＋ＣａＯ）が０．３以上であり、ＭｇＯ／（ＭｇＯ＋ＳｒＯ）が０．６０以上であり、Ａｌ２Ｏ３×（ＭｇＯ／（ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯ））が５．５以上である無アルカリガラス。     A glass glass manufacturing method in which a glass raw material is melted to form molten glass, the molten glass is formed into a plate-like glass ribbon with a molding device, and then the glass ribbon is gradually cooled with a slow cooling device,
    The plate glass is made of the following alkali-free glass,
    When the strain point of the alkali-free glass is T st (° C.), the time during which the atmosphere concentration immediately below the lower surface of the glass ribbon is 500 to 20000 ppm in the temperature range of T st + 70 ° C. to T st −50 ° C. A plate glass manufacturing method for supplying SO 2 gas so as to be 30 seconds or longer.
    Temperature at which the strain point is 710 to 750 ° C., the average coefficient of thermal expansion at 50 to 300 ° C. is 30 × 10 −7 to 43 × 10 −7 / ° C., and the glass viscosity is 10 2 dPa · s. T 2 is 1710 ° C. or lower, and the temperature T 4 at which the glass viscosity is 10 4 dPa · s is 1320 ° C. or lower,
    SiO 2 66 to 70 in terms of mol% based on oxide,
    Al 2 O 3 12-15,
    B 2 O 3 0-1.5,
    MgO 5 to 9.5,
    CaO 4-11,
    SrO 0.5-4.5,
    BaO 0 ~ 1,
    ZrO 2 0-2,
    MgO + CaO + SrO + BaO is more than 18.2 and 21 or less,
    MgO / (MgO + CaO + SrO + BaO) is 0.25 or more, MgO / (MgO + CaO) is 0.3 or more, MgO / (MgO + SrO) is 0.60 or more, and Al 2 O 3 × (MgO / (MgO + CaO + SrO + BaO) ) Is alkali-free glass of 5.5 or more.
  3. 　前記無アルカリガラスがアルカリ金属酸化物を６００～２０００モルｐｐｍ含有する、請求項１または２に記載の板ガラス製造方法。 The plate glass manufacturing method according to claim 1 or 2, wherein the alkali-free glass contains 600 to 2000 mol ppm of an alkali metal oxide.
  4. 　前記成形装置が、フロート成形装置である、請求項１～３のいずれか一項に記載の板ガラス製造方法。 The plate glass manufacturing method according to any one of claims 1 to 3, wherein the forming device is a float forming device.
  5. 　ＳｉＯ２原料の珪素源として、メディアン粒径Ｄ５０が２０μｍ～２７μｍ、粒径２μｍ以下の粒子の割合が０．３体積％以下、かつ粒径１００μｍ以上の粒子の割合が２．５体積％以下の珪砂を用いる、請求項１～４のいずれか一項に記載の板ガラスの製造方法。 As a silicon source of the SiO 2 raw material, the ratio of particles having a median particle diameter D 50 of 20 μm to 27 μm, a particle diameter of 2 μm or less is 0.3% by volume or less, and the ratio of particles having a particle diameter of 100 μm or more is 2.5% by volume or less. The method for producing a plate glass according to any one of claims 1 to 4, wherein the silica sand is used.
  6. 　ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯのアルカリ土類金属源として、アルカリ土類金属の水酸化物を、アルカリ土類金属源１００モル％（ＭＯ換算。但しＭはアルカリ土類金属元素である。以下同じ。）のうち、１５～１００モル％（ＭＯ換算）含有するものを用いる、請求項１～４のいずれか一項に記載の板ガラス製造方法。 As an alkaline earth metal source of MgO, CaO, SrO and BaO, an alkaline earth metal hydroxide is used in an amount of 100 mol% of alkaline earth metal source (in terms of MO, where M is an alkaline earth metal element. The same applies hereinafter. 5. The method for producing plate glass according to any one of claims 1 to 4, wherein a material containing 15 to 100 mol% (in terms of MO) is used.
  7. 　ＳｉＯ２原料の珪素源として、メディアン粒径Ｄ５０が２０μｍ～２７μｍ、粒径２μｍ以下の粒子の割合が０．３体積％以下、かつ粒径１００μｍ以上の粒子の割合が２．５体積％以下の珪砂を用い、ＭｇＯ、ＣａＯ、ＳｒＯおよびＢａＯのアルカリ土類金属源として、アルカリ土類金属の水酸化物を、アルカリ土類金属源１００モル％（ＭＯ換算。但しＭはアルカリ土類金属元素である。以下同じ。）のうち、１５～１００モル％（ＭＯ換算）含有するものを用いる、請求項１～４のいずれか一項に記載の板ガラス製造方法。 As a silicon source of the SiO 2 raw material, the ratio of particles having a median particle diameter D 50 of 20 μm to 27 μm, a particle diameter of 2 μm or less is 0.3% by volume or less, and the ratio of particles having a particle diameter of 100 μm or more is 2.5% by volume or less. As an alkaline earth metal source of MgO, CaO, SrO and BaO, an alkaline earth metal hydroxide is used as an alkaline earth metal source at 100 mol% (in terms of MO. M is an alkaline earth metal element) The method for producing a glass sheet according to any one of claims 1 to 4, wherein one containing 15 to 100 mol% (in terms of MO) is used.
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