WO2017038621A1 - Glass plate having uv resistance - Google Patents

Glass plate having uv resistance Download PDF

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Publication number
WO2017038621A1
WO2017038621A1 PCT/JP2016/074810 JP2016074810W WO2017038621A1 WO 2017038621 A1 WO2017038621 A1 WO 2017038621A1 JP 2016074810 W JP2016074810 W JP 2016074810W WO 2017038621 A1 WO2017038621 A1 WO 2017038621A1
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Prior art keywords
glass plate
irradiation
transmittance
glass
absorption coefficient
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PCT/JP2016/074810
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French (fr)
Japanese (ja)
Inventor
聡司 大神
小池　章夫
林　英明
円佳 小野
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旭硝子株式会社
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Publication of WO2017038621A1 publication Critical patent/WO2017038621A1/en

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    • 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
    • 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

Definitions

  • the present invention relates to a UV-irradiation glass plate and UV-irradiation glass plate having UV resistance, and more particularly to a high-intensity UV irradiation glass plate and UV-irradiation glass plate having UV resistance.
  • soda lime glass has been widely used for glass plates for display, but has poor chemical strengthening properties and poor strength properties.
  • aluminosilicate glass etc. are developed as glass for chemical strengthening which can implement
  • the chemically strengthened glass plate is useful for display applications because of its high strength, but it is required to have high transmittance in addition to high strength. Therefore, a highly permeable chemically strengthened glass plate with a reduced iron content that contributes to coloration has been studied.
  • Patent Document 1 As one of the factors that lower the transmittance of glass, so-called solarization is known in which the valence state of a transition metal changes due to the influence of ultraviolet rays or the like, and the color of the glass changes.
  • Patent Document 2 in order to increase the resistance to solarization of the glass, colored glass containing TiO 2 is disclosed.
  • Patent Document 2 discloses a highly transmissive soda lime glass in which a measure against solarization is achieved by reducing the iron content in the glass to 0.005 to 0.120% by weight.
  • a high-strength glass plate (chemically strengthened glass plate) subjected to chemical strengthening treatment is subjected to various pretreatments when used for a display or the like.
  • One of them is a cleaning treatment by UV irradiation on the short wavelength side using a low-pressure mercury lamp, and organic substances on the surface of the glass plate may be removed.
  • UV irradiation on the short wavelength side using a low-pressure mercury lamp
  • organic substances on the surface of the glass plate may be removed.
  • the transmittance in a specific wavelength region of the glass plate is reduced by UV irradiation on the short wavelength side.
  • UV on the short wavelength side is irradiated, the color of the glass plate is deteriorated according to the region where the transmittance is lowered.
  • the short wavelength side UV has a shorter wavelength than UV in solarization, which is cited as one of the problems in Patent Documents 1 and 2. It has been found that the chemically strengthened glass containing Ti described in Patent Document 1 does not exhibit the effect of suppressing the decrease in transmittance in the UV irradiation on the short wavelength side. Further, the glass described in Patent Document 2 is soda lime glass that has poor chemical strengthening properties and cannot achieve high strength, and further, there is no disclosure regarding resistance to UV on the short wavelength side. As a result of studies by the present inventors, it has been found that, in a high-strength glass plate, merely reducing the Fe content does not provide the effect of suppressing the decrease in transmittance in UV irradiation on the short wavelength side.
  • UV resistance refers to the change in transmittance of UV irradiation on the short wavelength side mainly using 185 nm and 254 nm using a low-pressure mercury lamp.
  • UV-C of 280 nm or less from sunlight is said to be completely absorbed by ozone and oxygen molecules in the stratosphere on the earth and hardly reaches the surface of the earth. It deals with a phenomenon different from “UV resistance” in the book.
  • the present invention relates to the following ⁇ 1> to ⁇ 8>.
  • ⁇ 1> By mass%, SiO 2 is 60 to 75%, Al 2 O 3 is 2 to 25%, Na 2 O is 10 to 20%, K 2 O is 0 to 7%, and MgO is 0.5 to 10 %, CaO 0-15% and Fe 2 O 3 0.035-0.12%,
  • a glass plate for UV irradiation having a redox ratio of less than 0.550 and a CaO / MgO (mass ratio) of 1.5 or less.
  • the absorption coefficient of Fe 2+ after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 ⁇ m is 0.001 cm ⁇ 1 or more larger than the absorption coefficient of Fe 2+ before the polishing, and then UV having a wavelength of 254 nm ⁇ 2>
  • the absorption coefficient of Fe 2+ after the UV-irradiated glass plate is held at a temperature of (Tg + 40) ° C. for 1 hour and slowly cooled to room temperature at a cooling rate of 1 ° C./min is the pre-treatment absorption coefficient.
  • the absorption coefficient of Fe 2+ is 0.001 cm ⁇ 1 or more larger than the absorption coefficient of Fe 2+
  • the absorption coefficient of Fe 2+ after irradiation with UV having a wavelength of 254 nm is smaller than the absorption coefficient of Fe 2+ before the irradiation by 0.017 cm ⁇ 1 or more.
  • the transmittance T1 ′′ satisfies the relationship ⁇ ln (T1 ′′ / T0 ′′) ⁇ 0.001, and then the transmittance T1 after irradiation with UV having a wavelength of 254 nm, the transmittance T0 before the irradiation,
  • ⁇ 8> The glass plate for UV irradiation according to ⁇ 1> or ⁇ 2>, wherein an average transmittance at a wavelength of 380 to 780 nm is 91% or more.
  • the present invention it is possible to obtain a UV irradiation glass plate and a UV irradiation glass plate that maintain high strength without lowering the transmittance in a specific wavelength region even when UV on the short wavelength side is irradiated. Therefore, a glass plate with high transmission and high strength can be obtained without deteriorating the color of the glass plate, and it is very useful as a chemically strengthened glass plate for which high transmission is required for display applications and the like.
  • UV irradiation glass plate means a glass plate before irradiation with short wavelength UV
  • UV irradiation glass plate means a glass plate after irradiation with short wavelength UV.
  • glass plates are sometimes collectively referred to simply as “glass plates”.
  • % when “%” is simply described, it means “% by mass”, and “ ⁇ ” means that the value is not less than the lower limit and not more than the upper limit.
  • the glass plate according to the present invention is expressed in terms of an oxide-based mass percentage (hereinafter sometimes simply referred to as “mass%”), and SiO 2 is 60 to 75%, Al 2 O 3 is 2 to 25%, 10-20% Na 2 O, 0-7% K 2 O, 0.5-10% MgO, 0-15% CaO and 0.035-0.12% Fe 2 O 3
  • the redox ratio is less than 0.550, and CaO / MgO (mass ratio) is 1.5 or less.
  • the composition of the glass plate can be measured simply by the fluorescent X-ray method, and more precisely by the wet analysis method.
  • the surface compressive stress (CS) is preferably 600 to 1000 MPa, and more preferably 650 to 950 MPa. If it is less than 600 MPa, scratches are likely to occur on the surface of the glass, and there is a possibility that a practically sufficient strength cannot be obtained.
  • the compressive stress layer depth (DOL; Depth of Layer) is preferably 5 to 50 ⁇ m, and more preferably 7 to 40 ⁇ m. If the surface is less than 5 ⁇ m, if the surface of the glass is scratched, the depth of the scratch may exceed the DOL and the glass may be easily broken.
  • CS tensile stress value
  • C Center Tension
  • the UV resistance means that a decrease in transmittance at a wavelength of 300 to 800 nm is suppressed when short-wavelength UV light such as a low-pressure mercury lamp is irradiated.
  • the UV irradiation on the short wavelength side is carried out at a wavelength of 100 to 280 nm in a range of 0.1 to 1000 mW / cm 2 and an irradiation time of 1 to 20000 seconds. From the aspect of reducing the processing cost, it is preferable that the irradiation time is 1 to 100 mW / cm 2 and the irradiation time is 1200 seconds or less.
  • the exposure preferably be carried out at the 10 ⁇ 10000mJ / cm 2 condition, more preferably of 50 ⁇ 5000mJ / cm 2 conditions.
  • the light source include a low-pressure mercury lamp having main wavelengths of 185 nm and 254 nm, an excimer lamp having a main wavelength of 172 nm, and the like.
  • This UV irradiation on the short wavelength side is generally used for UV cleaning treatment or UV sterilization treatment of a substrate.
  • solarization resistance due to sunlight is an evaluation for UV irradiation in a long wavelength region that is not absorbed by the stratosphere, and thus is an evaluation different from the evaluation for wavelengths of 300 nm or less in the present invention.
  • the transmittance at a wavelength of 300 to 800 nm before UV irradiation on the short wavelength side is T0 a
  • the transmittance at a wavelength of 300 to 800 nm after irradiation based on the irradiation condition A is preferably when formed into a T1 a
  • the UV induced absorption ⁇ at each wavelength represented by the following formula is 0.07 or less, and more preferably 0.05 or less.
  • the irradiation condition A means that a PLW 21-200 made by Sen Special Light Source is used for 600 seconds from a position 5 cm away from the surface of the glass plate using a 200 W low-pressure mercury lamp (EUV200GS-14: main wavelengths 185 nm and 254 nm). Irradiation.
  • EUV200GS-14 main wavelengths 185 nm and 254 nm.
  • the transmittance of a glass plate at a wavelength of 300 to 800 nm hardly changes before and after UV irradiation on the long wavelength side with a main wavelength of 365 nm using, for example, a high-pressure mercury lamp.
  • the transmittance decreases due to UV irradiation on the short wavelength side.
  • the degree of transmittance decrease is not uniform depending on the wavelength, and the rate of decrease varies depending on the wavelength, the color is complementary to the color of the wavelength region in which the transmittance is lower due to UV irradiation on the short wavelength side. As a result, the color becomes worse.
  • the glass composition in the present invention it is possible to suppress a decrease in transmittance at a wavelength of 300 to 800 nm before and after UV irradiation on the short wavelength side and to prevent the color of the glass plate from being deteriorated.
  • the UV resistance can be further improved by making Fe 2 O 3 0.035 to 0.12% and the redox ratio less than 0.550.
  • Fe 2 O 3 is preferably 0.05% or more, and more preferably 0.1% or more.
  • the redox ratio is preferably 0.500 or less, and more preferably 0.450 or less.
  • the redox ratio refers to the ratio (atomic ratio) of divalent iron Fe 2+ to the total iron Fe amount contained in the glass.
  • the redox ratio may be expressed in%.
  • the value of the redox ratio can be appropriately adjusted by introducing oxygen into the molten glass and oxidizing the divalent iron Fe 2+ to the trivalent iron Fe 3+ .
  • the redox ratio can be determined by a method such as quantifying Fe 2+ in glass by bipyridyl absorptiometry and quantifying the value of total iron Fe by ICP emission analysis. Note that the total iron amount can also be obtained simply by fluorescent X-rays.
  • the glass plate according to the present invention is preferably colorless glass when used for a display.
  • Colorless glass means glass having a coloring component of 2% or less, and glass having an average transmittance of 91% or more at a wavelength of 380 to 780 nm.
  • the coloring component is preferably 1% or less, more preferably 0.5% or less, further preferably 0.2% or less, and still more preferably substantially not contained. “Substantially not contained” means not containing any inevitable impurities.
  • the average transmittance at a wavelength of 380 to 780 nm is preferably 91% or more, more preferably 91.2% or more, and further preferably 91.4% or more.
  • the coloring component examples include a component represented by M p O q , where M is Co, Cu, V, Cr, Pr, Ce, Bi, Eu, Mn, Er, Ni, Nd, W, Rb, Sn, and It is at least one selected from the group consisting of Ag, and p and q represent the atomic ratio of M and O (oxygen atom).
  • the glass plate according to the present invention may contain other components as long as the effects are not impaired.
  • the component that may be included include SO 3 , ZnO 2 , ZrO 2 , TiO 2 , SrO, BaO, Li 2 O, Cs 2 O, Fr 2 O, AsO, SbO, and SeO 2 . These can be included in a total of 0 to 2%.
  • the total thickness of the glass plate may be 0.1 to 2 mm, and 0.2 to 1 mm is preferable from the viewpoint of achieving both rigidity and light weight.
  • SiO 2 is known as a component that forms a network structure in the glass microstructure, and is a main component constituting the glass.
  • the content of SiO 2 is 60% or more, preferably 63% or more, more preferably 65% or more, particularly preferably at least 67%.
  • the content of SiO 2 is 75% or less, preferably 73% or less, more preferably 71% or less, and particularly preferably 70% or less.
  • the content of SiO 2 is 60% or more, it is advantageous in terms of stability and weather resistance as glass. Moreover, an increase in thermal expansion can be suppressed by forming a network structure.
  • the content of SiO 2 is 75% or less, it is advantageous in terms of solubility and moldability.
  • Al 2 O 3 has an effect of improving the ion exchange performance in chemical strengthening, and in particular, an effect of improving CS. It is also known as a component that improves the weather resistance of glass. Moreover, there exists an effect
  • the content of Al 2 O 3 is 2% or more, preferably 3% or more, more preferably 4% or more.
  • the content of Al 2 O 3 is 25% or less, preferably 20% or less, more preferably 15% or less, still more preferably 9.5% or less, and particularly preferably 8.6% or less.
  • a desired CS value is obtained by ion exchange, and in addition to the float method, tin from the surface (bottom surface) in contact with the tin melting bath is obtained.
  • the effect of suppressing intrusion and making the glass difficult to warp during chemical strengthening, the effect of stability against moisture content change, and the effect of promoting dealkalization are obtained.
  • the content of Al 2 O 3 is 25% or less, the devitrification temperature does not increase greatly even when the viscosity of the glass is high, which is advantageous in terms of melting and forming in a float facility.
  • B 2 O 3 is a component that promotes melting of the glass raw material and improves mechanical properties and weather resistance, but it does not cause inconveniences such as generation of striae due to volatilization and furnace wall erosion. You may contain in 6% or less of range. When it contains B 2 O 3 , it is preferably 5% or less, more preferably 4% or less, and particularly preferably not substantially contained.
  • Na 2 O is an essential component for forming a surface compressive stress layer by ion exchange, and has the effect of deepening the DOL. Moreover, it is a component which lowers
  • Na 2 O is a component that generates non-crosslinked oxygen, and the variation in chemical strengthening characteristics when the amount of moisture in the glass varies is reduced.
  • the content of Na 2 O is 10% or more, preferably 11% or more, more preferably 13% or more. Further, the content of Na 2 O is 20% or less, preferably 18% or less, more preferably 16% or less.
  • a desired surface compressive stress layer can be formed by ion exchange, and fluctuations due to changes in moisture content can be suppressed.
  • the content of Na 2 O is 20% or less, sufficient weather resistance can be obtained, the amount of intrusion of tin from the bottom surface during molding by the float method can be suppressed, and the glass is hardly warped after chemical strengthening treatment. be able to.
  • K 2 O is an ingredient that increases the ion exchange rate, deepens the DOL, lowers the melting temperature of the glass, and increases non-crosslinked oxygen, so it may be contained in a range of 7% or less. If it is 7% or less, the DOL does not become too deep, sufficient CS is obtained, and the melting temperature of the glass can be lowered. Preferably 5% or less when they contain K 2 O, more preferably 4% or less, more preferably 2% or less. On the other hand, since a small amount of K 2 O has an effect of suppressing the amount of intrusion of tin from the bottom surface at the time of molding by the float process, it is preferably contained when molding by the float process. In this case, the content of K 2 O is preferably 0.01% or more, more preferably 0.1% or more.
  • MgO is a component that can stabilize the glass, improve the solubility, and reduce the alkali metal content by adding this to suppress an increase in the coefficient of thermal expansion (CTE).
  • the content of MgO is 0.5% or more, preferably 3% or more, more preferably 5% or more. Further, the content of MgO is 10% or less, preferably 9% or less, more preferably 8% or less. When the content of MgO is 0.5% or more, the CTE increase suppressing effect is exhibited. On the other hand, when the content of MgO is 10% or less, the difficulty of devitrification is maintained, or a sufficient ion exchange rate is obtained.
  • CaO is a component that stabilizes the glass, and has the effect of improving the solubility while preventing devitrification due to the presence of MgO and suppressing an increase in CTE.
  • the content of CaO is 0 to 15%, preferably 0.5 to 12%, more preferably 2 to 10%. When the content of CaO is 15% or less, a sufficient ion exchange rate is obtained, and a desired DOL is obtained.
  • CaO is preferably less than 5%, more preferably 4% or less.
  • CaO / MgO (mass ratio) is preferably 1.5 or less from the viewpoint of improving ion exchange performance in chemical strengthening and increasing the transmittance of the glass plate. More preferably, it is 0.1 to 1.2, and still more preferably 0.2 to 1.0.
  • SO 3 , chlorides, fluorides and the like may be appropriately contained in the range of 0 to 1% as glass refining agents.
  • Absorption coefficient alpha Fe @ 2 + and is of Fe 2+ of the glass plate in the present specification the absorption at a wavelength of 780nm regarded as zero, may be determined according to the following equation.
  • the reason why the absorption at the wavelength of 780 nm is regarded as zero and used as a reference is to subtract the influence of the reflection of the glass plate.
  • ⁇ Fe2 + 2.303 ⁇ log ( T 780 / Ti) / d Ti: Transmittance of measurement wavelength (%)
  • T780 Transmittance (%) at a wavelength of 780 nm
  • d Glass thickness (cm)
  • the measurement wavelength for Ti is 380 to 780 nm.
  • the absorption coefficient and transmittance of Fe 2+ of the UV-irradiated glass plate vary depending on the irradiation time and irradiation intensity of the irradiated UV. Therefore, in order to uniformly evaluate the characteristics of the glass plate, after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 ⁇ m, UV irradiation is again performed under the irradiation condition A to measure the absorption coefficient and transmittance of Fe 2+. I do. Since the absorption coefficient of Fe 2+ of the glass plate after polishing 150 ⁇ m in the depth direction from the surface is the same value as the absorption coefficient of Fe 2+ of the glass plate not irradiated with UV, the glass plate after polishing is UV-treated. It can be regarded as an unirradiated glass plate.
  • the absorption coefficient of Fe 2+ after polishing (corresponding to UV non-irradiation) is the same as that before polishing (UV irradiation in the actual process).
  • the absorption coefficient of Fe 2+ after) is 0.001 cm ⁇ 1 or more.
  • the absorption coefficient of Fe 2+ after irradiation with UV under irradiation condition A following the polishing is 0.017 cm ⁇ 1 or more smaller than the absorption coefficient of Fe 2+ before irradiation. Is preferable, and it is more preferably 0.019 cm ⁇ 1 or less.
  • the absorption coefficient of the Fe 2+ after UV irradiation of the short wavelength side is smaller than the absorption coefficient of the Fe 2+ before UV irradiation
  • the surface layer portion of the glass plate of the Fe 2+ ⁇ Fe 3+ Indicates that a reaction is taking place.
  • the absorption coefficient of Fe 2+ after UV irradiation is preferably 0.017 cm ⁇ 1 or more smaller than the absorption coefficient of Fe 2+ before UV irradiation.
  • a slow cooling process may be performed instead of the above polishing. That is, since the absorption coefficient of Fe 2+ of the glass plate after performing the slow cooling treatment under a certain condition is the same value as the absorption coefficient of Fe 2+ of the glass plate not irradiated with UV, the slow cooling treatment The latter glass plate can be regarded as a glass plate not irradiated with UV.
  • the absorption coefficient of Fe 2+ after the slow cooling process (corresponding to UV non-irradiation) is the same as that before the slow cooling process (actual process). larger 0.001 cm -1 or more than the absorption coefficient of the Fe 2+ after UV irradiation) in.
  • the UV-irradiated glass plate is held at a temperature of (Tg + 40) ° C. for 1 hour and slowly cooled to room temperature at a cooling rate of 1 ° C./min.
  • the absorption coefficient of Fe 2+ after irradiation with UV under irradiation condition A following the slow cooling treatment is 0.017 cm ⁇ 1 or more than the absorption coefficient of Fe 2+ before irradiation. It is preferably small, more preferably 0.019 cm ⁇ 1 or more.
  • the transmittance can be regarded as a glass plate not irradiated with UV by performing the above polishing or slow cooling treatment on the UV irradiated glass plate.
  • a shorter irradiation time or a lower irradiation intensity is often used compared to the irradiation condition A, and the transmittance T0 ′ or T0 ′′ after polishing or annealing (corresponding to UV non-irradiation) and polishing or
  • the transmittance T1 ′ or T1 ′′ before annealing is ⁇ ln (T1 ′ / T0 ′) ⁇ 0.001 or ⁇ ln (T1 ′′ / T0 ′′) ⁇ The relationship of 0.001 is satisfied.
  • the UV-irradiated glass plate according to the present invention has a transmittance T1 b after irradiation with UV under irradiation condition A following the polishing or annealing process and a transmittance T0 b before UV irradiation of ⁇ ln (T1 b / It is preferable to satisfy the relationship of T0 b ) ⁇ 0.07, and more preferably 0.05 or less.
  • the transmittances Tn b , Tn ′ and Tn ′′ and the above-described Tn a are all transmittances at wavelengths of 300 to 800 nm, and the transmittances T1 a and T1 b are the irradiation conditions described above.
  • a transmittance after UV irradiation with A is the same as a transmittance for UV irradiation with A.
  • the glass transition temperature (Tg) of the glass plate according to the present invention is, for example, 530 ° C. or more, preferably 540 ° C. or more, more preferably 550 ° C. or more, and further preferably 550 to 600 ° C. preferable.
  • Tg is 530 ° C. or higher, it is advantageous in terms of suppression of stress relaxation and thermal warpage during chemical strengthening treatment.
  • Tg can be adjusted by adjusting the total amount of SiO 2 and Al 2 O 3 and the amount of alkali metal oxide and alkaline earth oxide.
  • the thermal expansion coefficient CTE of the glass plate according to the present invention is, for example, 80 ⁇ 10 ⁇ 7 to 100 ⁇ 10 ⁇ 7 / K, preferably 80 ⁇ 10 ⁇ 7 to 95 ⁇ 10 in the temperature range of 50 to 350 ° C. -7 / K.
  • CTE can be adjusted by adjusting the amount of alkali metal oxide and alkaline earth oxide.
  • the density at room temperature of the glass plate according to the present invention is 2.38 from the viewpoint of reducing the difference in density from soda lime glass, considering that it is alternately produced in the same float equipment as normal soda lime glass.
  • To 2.54 g / cm 3 preferably 2.40 to 2.52 g / cm 3 .
  • the manufacturing method of the glass plate for UV irradiation which concerns on this invention is not specifically limited,
  • molding molten glass into a plate-shaped glass plate is not specifically limited.
  • appropriate amounts of various raw materials are prepared, heated to about 1500-1600 ° C and melted, and then homogenized by defoaming, stirring, etc., and the plate is obtained by a well-known float method, downdraw method (fusion method, etc.), press method, etc. Or cast into a block shape, and after slow cooling, cut into a desired size to produce a glass plate.
  • a polishing process is performed as necessary, but it is also possible to treat the glass plate surface with a fluorine agent in addition to or instead of the polishing process.
  • the glass plate after production is SiO 2 60-75%, Al 2 O 3 2-25%, Na 2 O 10-20%, K 2 O 0-7%, MgO 0.5-10%
  • the raw materials are selected so that 0-15% of CaO and 0.035-0.12% of Fe 2 O 3 are contained, and CaO / MgO (mass ratio) is 1.5 or less.
  • the UV irradiation glass plate concerning this invention is obtained by irradiating UV of the short wavelength side to the obtained glass plate for UV irradiation.
  • the glass plate is preheated to about 400 ° C., and ion exchange is performed between Na on the surface of the glass plate and K in the molten salt in the molten salt. It is preferable to perform a chemical strengthening treatment. Further, after ion exchange in a molten salt containing a specific salt, an acid treatment and an alkali treatment may be performed to obtain a chemically strengthened glass plate having higher strength.
  • the obtained glass plate preferably has a CS of 600 to 1000 MPa, more preferably 650 to 950 MPa.
  • CS can be adjusted by adjusting Na concentration, strengthening time and molten salt temperature in the molten potassium nitrate salt used for ion exchange.
  • the Na concentration in the molten potassium nitrate is reduced.
  • the Na concentration is preferably 3% by mass or less, more preferably 2.5% by mass or less, and further preferably 1% by mass or less.
  • the DOL is preferably 5 to 50 ⁇ m, more preferably 7 to 40 ⁇ m. DOL can be adjusted by adjusting Na concentration, strengthening time and molten salt temperature in the molten potassium nitrate salt used for ion exchange.
  • the temperature of the molten salt is increased.
  • the temperature of the molten salt is preferably 400 ° C or higher, more preferably 420 ° C or higher, and further preferably 430 ° C or higher.
  • the glass plate of this embodiment can be cut after chemical strengthening.
  • a cutting method scribing and breaking with a normal wheel tip cutter can be applied, and laser cutting is also possible.
  • the cutting edge may be chamfered after cutting.
  • the chamfering may be a mechanical grinding process or a method of treating with a chemical solution such as hydrofluoric acid.
  • ⁇ Glass composition The composition of the obtained glass plate was identified by the fluorescent X-ray method.
  • the redox ratio was determined by quantifying Fe 2+ in the glass by bipyridyl absorptiometry and quantifying the value of total Fe by ICP emission spectrometry. These results are shown in Table 1.
  • UV irradiation glass plate is irradiated with UV under irradiation condition A, that is, the light of a low-pressure mercury lamp (main wavelengths 185 nm and 254 nm) is irradiated for 600 seconds from a position 5 cm away, and then transmitted through the UV irradiation glass plate at a wavelength of 200 to 2500 nm. The rate was measured. The transmittance was measured in steps of 1 nm with a spectrophotometer trade name U-4100 manufactured by Hitachi High-Technologies Corporation.
  • Table 1 shows the results of the UV resistance test.
  • ⁇ (UV resistance) indicates the value of UV-induced absorption ⁇ at a wavelength where the difference in UV-induced absorption was the largest before and after light irradiation.
  • ⁇ indicates that the UV-induced absorption ⁇ was 0.07 or less at the wavelength where the difference in UV-induced absorption was the largest before and after light irradiation.
  • X means that the UV-induced absorption ⁇ was larger than 0.07.
  • ⁇ Redox ratio> The obtained glass was pulverized and dissolved in an HF aqueous solution to prepare a test liquid.
  • the test liquid, a 2,2′-dipyridyl solution, and an ammonium acetate solution were mixed to develop color, the absorption peak intensity was measured, and the Fe 2+ amount was calculated based on a calibration curve prepared in advance.
  • the above test liquid, hydroxylamine hydrochloric acid solution, 2,2'-dipyridyl solution, and ammonium acetate solution were mixed to reduce the color of all iron to divalent iron, and the absorbance peak intensity. To calculate the total iron content.
  • the ratio (redox ratio) between the amount of Fe 2+ and the total iron Fe was determined and indicated in% in the “Redox” column of Table 1.
  • the Fe 2+ absorption coefficient (cm ⁇ 1 ) of the polished glass plate after polishing the surface of the UV irradiated glass plate in the depth direction by 150 ⁇ m is the glass plate not irradiated with UV (glass plate for UV irradiation).
  • the Fe 2+ absorption coefficient (cm ⁇ 1 ) after polishing the UV-irradiated glass plate becomes the same value as “Fe 2+ absorption coefficient (cm ⁇ 1 ) before light irradiation” in Table 1, and the UV-irradiated glass plate
  • the Fe 2+ absorption coefficient (cm ⁇ 1 ) after polishing is 0.001 cm ⁇ 1 or more larger than the Fe 2+ absorption coefficient (cm ⁇ 1 ) before polishing.
  • Fe 2+ absorption coefficient (cm ⁇ 1 ) after the UV irradiation glass plate was polished and irradiated with UV under the irradiation condition A was almost the same as “Fe 2+ absorption coefficient (cm ⁇ 1 ) after light irradiation” in Table 1. Value.
  • Table 1 shows the value of ⁇ ln (T1 a / T0 a ) derived by using the transmittances T0 a and T1 a at wavelengths of 300 to 800 nm before and after the UV irradiation glass plate was irradiated with UV under the irradiation condition A.
  • the transmittance T1 b after the UV irradiation glass plate is irradiated with UV under the irradiation condition A after polishing the UV irradiation glass plate is similar to the transmittance T1 a after the UV irradiation glass plate is irradiated with the UV under the irradiation condition A.
  • the value of ⁇ ln (T1 b / T0 b ) calculated from the transmittance before and after UV irradiation under irradiation condition A after polishing the UV-irradiated glass plate is represented by “ ⁇ (UV resistance)” in Table 1. This is approximately the same as the value of ⁇ ln (T1 a / T0 a ).
  • the UV irradiating glass plate was held at (Tg + 40) ° C. for 1 hour, and the glass plate treated with gradual cooling to room temperature at a cooling rate of 1 ° C./min was subjected to the absorption coefficient and transmittance of Fe 2+. It can be considered that it is the same as the said grinding
  • the coefficient of thermal expansion is based on JIS R 1618: 2002, measured at a rate of temperature increase of 5 ° C./minute using a thermal dilatometer (Bruker Ax, TD5000SA), and an average linear expansion of 50 to 350 ° C. The rate was determined. Moreover, the glass transition temperature (Tg) was calculated
  • the glass plate was chemically strengthened by immersion in molten potassium nitrate having a concentration of 98% and a temperature of 425 ° C. for 3 hours.
  • the values of CS (MPa) and DOL ( ⁇ m) of the obtained chemically strengthened glass plate were measured with a surface stress meter FSM-6000 manufactured by Orihara Seisakusho and calculated as a calculated value.
  • the results are shown in “CS (MPa)” and “DOL ( ⁇ m)” in Table 1, respectively.
  • “DOL determination” of “ ⁇ ” indicates that the DOL is 8 ⁇ m or more, and “X” indicates that the DOL is less than 8 ⁇ m.
  • the present invention it is possible to obtain a glass plate excellent in UV resistance that maintains high strength without lowering the transmittance in a specific wavelength region even when UV on the short wavelength side is irradiated. Therefore, a glass plate with high transmission and high strength can be obtained without deteriorating the color of the glass plate, and it is very useful as a chemically strengthened glass plate for which high transmission is required for display applications and the like.

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Abstract

The objective of the present invention is to provide a high-strength glass plate having UV resistance, which maintains the high strength without being decreased in the transmittance in a specific wavelength range even if irradiated with short wavelength UV. The present invention relates to a glass plate for UV irradiation, which contains, in mass%, 60-75% of SiO2, 2-25% of Al2O3, 10-20% of Na2O, 0-7% of K2O, 0.5-10% of MgO, 0-15% of CaO and 0.035-0.12% of Fe2O3, and which has a redox ratio of less than 0.550 and a CaO/MgO (mass ratio) of 1.5 or less.

Description

ＵＶ耐性を有するガラス板Glass plate having UV resistance
　本発明はＵＶ耐性を有するＵＶ照射用ガラス板及びＵＶ照射ガラス板に関し、より詳細には、ＵＶ耐性を有する高強度なＵＶ照射用ガラス板及びＵＶ照射ガラス板に関する。 The present invention relates to a UV-irradiation glass plate and UV-irradiation glass plate having UV resistance, and more particularly to a high-intensity UV irradiation glass plate and UV-irradiation glass plate having UV resistance.
　近年、携帯電話または携帯情報端末（ＰＤＡ）、パーソナルコンピュータ、テレビ、車載ナビゲーション表示装置等のディスプレイにおいて、高強度なガラスが求められている。従来、ディスプレイ用途のガラス板にはソーダライムガラスが広く用いられていたが、化学強化特性が悪く、強度特性が悪い。そこで、化学強化処理により高強度の実現が可能な化学強化用ガラスとして、アルミノシリケートガラス等が開発されている。 In recent years, high-strength glass has been demanded for displays such as mobile phones or personal digital assistants (PDAs), personal computers, televisions, and in-vehicle navigation display devices. Conventionally, soda lime glass has been widely used for glass plates for display, but has poor chemical strengthening properties and poor strength properties. Then, aluminosilicate glass etc. are developed as glass for chemical strengthening which can implement | achieve high intensity | strength by a chemical strengthening process.
　化学強化ガラス板は高強度であることからディスプレイ用途として有用であるが、高強度に加えて高透過であることが求められる。そのため、呈色の一因となる鉄の含有量を減らした高透過な化学強化ガラス板が検討されている。 The chemically strengthened glass plate is useful for display applications because of its high strength, but it is required to have high transmittance in addition to high strength. Therefore, a highly permeable chemically strengthened glass plate with a reduced iron content that contributes to coloration has been studied.
　ガラスの透過率を下げる要因のひとつとして、紫外線等の影響により遷移金属の価数状態が変わってガラスの色が変化する、いわゆるソラリゼーションが知られている。
　特許文献１では、ガラスの耐ソラリゼーション性を高めるために、ＴｉＯ２を含む有色ガラスが開示されている。また、特許文献２にはガラス中の鉄含有量を０．００５～０．１２０重量％と少なくすることにより、ソラリゼーション対策をした高透過なソーダライムガラスが開示されている。 As one of the factors that lower the transmittance of glass, so-called solarization is known in which the valence state of a transition metal changes due to the influence of ultraviolet rays or the like, and the color of the glass changes.
In Patent Document 1, in order to increase the resistance to solarization of the glass, colored glass containing TiO 2 is disclosed. Patent Document 2 discloses a highly transmissive soda lime glass in which a measure against solarization is achieved by reducing the iron content in the glass to 0.005 to 0.120% by weight.
国際公開第２０１３／０２１９７５号International Publication No. 2013/021975 日本国特表２０１２－５０９２４６号公報Japan Special Table 2012-509246
　化学強化処理をした高強度のガラス板（化学強化ガラス板）は、ディスプレイ等に用いる際、様々な前処理がされる。そのひとつとして、低圧水銀ランプを用いた短波長側のＵＶ照射による洗浄処理が挙げられ、ガラス板表面の有機物の除去を行う場合がある。
　ところが、本発明者らの検討により、短波長側のＵＶ照射により、ガラス板の特定の波長領域における透過率が低下することが判明した。その結果、短波長側のＵＶを照射すると、透過率が低下した領域に応じてガラス板の色味が悪くなる。 A high-strength glass plate (chemically strengthened glass plate) subjected to chemical strengthening treatment is subjected to various pretreatments when used for a display or the like. One of them is a cleaning treatment by UV irradiation on the short wavelength side using a low-pressure mercury lamp, and organic substances on the surface of the glass plate may be removed.
However, as a result of studies by the present inventors, it has been found that the transmittance in a specific wavelength region of the glass plate is reduced by UV irradiation on the short wavelength side. As a result, when UV on the short wavelength side is irradiated, the color of the glass plate is deteriorated according to the region where the transmittance is lowered.
　当該短波長側のＵＶとは、特許文献１及び２で課題のひとつとして挙げられているソラリゼーションにおけるＵＶと比べて波長が短い。特許文献１に記載のＴｉを含有した化学強化ガラスは、短波長側のＵＶ照射においては、透過率低下抑制の効果は奏さないことが判明した。また、特許文献２に記載のガラスは化学強化特性が悪く、高強度が達成できないソーダライムガラスであり、さらには、短波長側のＵＶに対する耐性に関しては一切開示されていない。本発明者らの検討により、高強度なガラス板において、Ｆｅ含有量を少なくするだけでは、短波長側のＵＶ照射における透過率低下抑制の効果は奏さないことが判明した。 The short wavelength side UV has a shorter wavelength than UV in solarization, which is cited as one of the problems in Patent Documents 1 and 2. It has been found that the chemically strengthened glass containing Ti described in Patent Document 1 does not exhibit the effect of suppressing the decrease in transmittance in the UV irradiation on the short wavelength side. Further, the glass described in Patent Document 2 is soda lime glass that has poor chemical strengthening properties and cannot achieve high strength, and further, there is no disclosure regarding resistance to UV on the short wavelength side. As a result of studies by the present inventors, it has been found that, in a high-strength glass plate, merely reducing the Fe content does not provide the effect of suppressing the decrease in transmittance in UV irradiation on the short wavelength side.
　したがって本発明では、低圧水銀ランプ等の短波長側のＵＶを照射しても、特定の波長領域における透過率を下げることなく、また高強度も維持した、ＵＶ耐性を有する高強度なＵＶ照射用ガラス板及びＵＶ照射ガラス板を提供することを目的とする。
　なお、本明細書においてＵＶ耐性とは、低圧水銀ランプを用いた１８５ｎｍおよび２５４ｎｍを主とした短波長側のＵＶ照射の透過率変化を対象としている。一方で、太陽光からの２８０ｎｍ以下のＵＶ－Ｃは、地球上の成層圏でオゾン及び酸素分子によって完全に吸収されると言われているため地表にはほとんど届かず、いわゆる「ソラリゼーション」と本明細書における「ＵＶ耐性」とは異なる現象を対象としている。 Therefore, in the present invention, even when UV is irradiated on the short wavelength side such as a low-pressure mercury lamp, the UV intensity is high and UV intensity is maintained without decreasing the transmittance in a specific wavelength region and maintaining high intensity. It aims at providing a glass plate and a UV irradiation glass plate.
In this specification, UV resistance refers to the change in transmittance of UV irradiation on the short wavelength side mainly using 185 nm and 254 nm using a low-pressure mercury lamp. On the other hand, UV-C of 280 nm or less from sunlight is said to be completely absorbed by ozone and oxygen molecules in the stratosphere on the earth and hardly reaches the surface of the earth. It deals with a phenomenon different from “UV resistance” in the book.
　本発明者らは、鋭意研鑽を積んだ結果、特定のガラス組成を採用することにより、短波長側のＵＶを照射しても特定の波長領域における透過率を下げることなく、高強度を維持したガラス板を得られることを見出し、本発明を完成するに至った。 As a result of earnest study, the present inventors have adopted a specific glass composition, so that high intensity is maintained without lowering the transmittance in a specific wavelength region even when UV on the short wavelength side is irradiated. It discovered that a glass plate could be obtained and came to complete this invention.
　すなわち、本発明は下記＜１＞～＜８＞に関するものである。
＜１＞　質量％で、ＳｉＯ２を６０～７５％、Ａｌ２Ｏ３を２～２５％、Ｎａ２Ｏを１０～２０％、Ｋ２Ｏを０～７％、ＭｇＯを０．５～１０％、ＣａＯを０～１５％及びＦｅ２Ｏ３を０．０３５～０．１２％含有し、
　レドックス比が０．５５０未満であり、かつ
　ＣａＯ／ＭｇＯ（質量比）が１．５以下であるＵＶ照射用ガラス板。
＜２＞　Ａｌ２Ｏ３を質量％で２～９．５％含有する前記＜１＞に記載のＵＶ照射用ガラス板。
＜３＞　前記＜１＞または＜２＞に記載のＵＶ照射用ガラス板にＵＶが照射されたＵＶ照射ガラス板。
＜４＞　ＵＶ照射ガラス板を表面から深さ方向に１５０μｍ研磨した後のＦｅ２＋の吸収係数が、前記研磨前のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きく、次いで波長２５４ｎｍのＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さい前記＜３＞に記載のＵＶ照射ガラス板。
＜５＞　ＵＶ照射ガラス板を（Ｔｇ＋４０）℃の温度で１時間保持し、１℃／分の冷却速度で室温まで徐冷する処理を行った後のＦｅ２＋の吸収係数が、前記処理前のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きく、次いで波長２５４ｎｍのＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さい前記＜３＞に記載のＵＶ照射ガラス板。
＜６＞　ＵＶ照射ガラス板を表面から深さ方向に１５０μｍ研磨した後の透過率Ｔ０’と、前記研磨前の透過率Ｔ１’とが－ｌｎ（Ｔ１’／Ｔ０’）≧０．００１の関係を満たし、次いで波長２５４ｎｍのＵＶを照射した後の透過率Ｔ１と、前記照射前の透過率Ｔ０とが－ｌｎ（Ｔ１／Ｔ０）≦０．０７の関係を満たす前記＜３＞に記載のＵＶ照射ガラス板。
＜７＞　ＵＶ照射ガラス板を（Ｔｇ＋４０）℃の温度で１時間保持し、１℃／分の冷却速度で室温まで徐冷する処理を行った後の透過率Ｔ０’’と、前記処理前の透過率Ｔ１’’とが－ｌｎ（Ｔ１’’／Ｔ０’’）≧０．００１の関係を満たし、次いで波長２５４ｎｍのＵＶを照射した後の透過率Ｔ１と、前記照射前の透過率Ｔ０とが－ｌｎ（Ｔ１／Ｔ０）≦０．０７の関係を満たす前記＜３＞に記載のＵＶ照射ガラス板。
＜８＞　波長３８０～７８０ｎｍにおける平均透過率が９１％以上である前記＜１＞または＜２＞に記載のＵＶ照射用ガラス板。 That is, the present invention relates to the following <1> to <8>.
<1> By mass%, SiO 2 is 60 to 75%, Al 2 O 3 is 2 to 25%, Na 2 O is 10 to 20%, K 2 O is 0 to 7%, and MgO is 0.5 to 10 %, CaO 0-15% and Fe 2 O 3 0.035-0.12%,
A glass plate for UV irradiation having a redox ratio of less than 0.550 and a CaO / MgO (mass ratio) of 1.5 or less.
<2> The glass plate for UV irradiation according to <1>, containing 2 to 9.5% by mass of Al 2 O 3 .
<3> A UV-irradiated glass plate obtained by irradiating UV onto the glass plate for UV irradiation according to <1> or <2>.
<4> The absorption coefficient of Fe 2+ after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 μm is 0.001 cm −1 or more larger than the absorption coefficient of Fe 2+ before the polishing, and then UV having a wavelength of 254 nm <2> The UV-irradiated glass plate according to <3>, wherein the absorption coefficient of Fe 2+ after irradiation is smaller by 0.017 cm −1 or more than the absorption coefficient of Fe 2+ before irradiation.
<5> The absorption coefficient of Fe 2+ after the UV-irradiated glass plate is held at a temperature of (Tg + 40) ° C. for 1 hour and slowly cooled to room temperature at a cooling rate of 1 ° C./min is the pre-treatment absorption coefficient. The absorption coefficient of Fe 2+ is 0.001 cm −1 or more larger than the absorption coefficient of Fe 2+ , and the absorption coefficient of Fe 2+ after irradiation with UV having a wavelength of 254 nm is smaller than the absorption coefficient of Fe 2+ before the irradiation by 0.017 cm −1 or more. UV irradiation glass plate as described in said <3>.
<6> Relationship between transmittance T0 ′ after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 μm and transmittance T1 ′ before polishing is −ln (T1 ′ / T0 ′) ≧ 0.001 And then the transmittance T1 after irradiation with UV having a wavelength of 254 nm and the transmittance T0 before irradiation satisfy the relationship of −ln (T1 / T0) ≦ 0.07. Irradiated glass plate.
<7> The transmittance T0 ″ after the UV irradiation glass plate was treated at a temperature of (Tg + 40) ° C. for 1 hour and gradually cooled to room temperature at a cooling rate of 1 ° C./min, and before the treatment The transmittance T1 ″ satisfies the relationship −ln (T1 ″ / T0 ″) ≧ 0.001, and then the transmittance T1 after irradiation with UV having a wavelength of 254 nm, the transmittance T0 before the irradiation, The UV-irradiated glass plate according to <3>, wherein satisfies the relationship of −ln (T1 / T0) ≦ 0.07.
<8> The glass plate for UV irradiation according to <1> or <2>, wherein an average transmittance at a wavelength of 380 to 780 nm is 91% or more.
　本発明によれば、短波長側のＵＶを照射しても、特定の波長領域における透過率を下げることなく、高強度を維持したＵＶ照射用ガラス板及びＵＶ照射ガラス板を得ることができる。そのため、ガラス板の色味を悪くすることなく高透過かつ高強度のガラス板が得られ、ディスプレイ用途等、高透過が求められる化学強化ガラス板として非常に有用である。 According to the present invention, it is possible to obtain a UV irradiation glass plate and a UV irradiation glass plate that maintain high strength without lowering the transmittance in a specific wavelength region even when UV on the short wavelength side is irradiated. Therefore, a glass plate with high transmission and high strength can be obtained without deteriorating the color of the glass plate, and it is very useful as a chemically strengthened glass plate for which high transmission is required for display applications and the like.
　以下、本発明を詳細に説明するが、本発明は以下の実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において、任意に変形して実施することができる。なお、本明細書において「ＵＶ照射用ガラス板」とは短波長側のＵＶを照射する前のガラス板を表し、「ＵＶ照射ガラス板」とは短波長側のＵＶを照射した後のガラス板を表し、それらを総称して単に「ガラス板」と称することがある。また単に「％」と記載した場合には「質量％」を意味し、「～」とはその下限の値以上、その上限の値以下であることを意味する。 Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention. In this specification, “UV irradiation glass plate” means a glass plate before irradiation with short wavelength UV, and “UV irradiation glass plate” means a glass plate after irradiation with short wavelength UV. Are sometimes collectively referred to simply as “glass plates”. In addition, when “%” is simply described, it means “% by mass”, and “˜” means that the value is not less than the lower limit and not more than the upper limit.
＜ガラス板＞
　本発明に係るガラス板は、酸化物基準の質量百分率表示（以下、単に「質量％」と称することがある。）で、ＳｉＯ２を６０～７５％、Ａｌ２Ｏ３を２～２５％、Ｎａ２Ｏを１０～２０％、Ｋ２Ｏを０～７％、ＭｇＯを０．５～１０％、ＣａＯを０～１５％及びＦｅ２Ｏ３を０．０３５～０．１２％含有し、レドックス比が０．５５０未満であり、かつＣａＯ／ＭｇＯ（質量比）が１．５以下であることを特徴とする。
　ガラス板の組成は、簡易的には蛍光Ｘ線法により測定することができ、より正確には湿式分析法により測定できる。 <Glass plate>
The glass plate according to the present invention is expressed in terms of an oxide-based mass percentage (hereinafter sometimes simply referred to as “mass%”), and SiO 2 is 60 to 75%, Al 2 O 3 is 2 to 25%, 10-20% Na 2 O, 0-7% K 2 O, 0.5-10% MgO, 0-15% CaO and 0.035-0.12% Fe 2 O 3 The redox ratio is less than 0.550, and CaO / MgO (mass ratio) is 1.5 or less.
The composition of the glass plate can be measured simply by the fluorescent X-ray method, and more precisely by the wet analysis method.
　本発明に係るガラス板を強化した際の強度は表面圧縮応力値（ＣＳ；Ｃｏｍｐｒｅｓｓｉｖｅ　Ｓｔｒｅｓｓ）は６００～１０００ＭＰａが好ましく、６５０～９５０ＭＰａがより好ましい。６００ＭＰａ未満であると、ガラスの表面に傷が生じやすく、実用上十分な強度が得られないおそれがある。
　圧縮応力層深さ（ＤＯＬ；Ｄｅｐｔｈ　ｏｆ　Ｌａｙｅｒ）は５～５０μｍが好ましく、７～４０μｍがより好ましい。５μｍ未満であると、ガラスの表面に傷が生じた場合、その傷の深さがＤＯＬを超えてガラスが破壊され易くなるおそれがある。
　ＣＳが大きすぎたり、ＤＯＬが深くなりすぎたりすると、ガラス中央の引張応力値（ＣＴ；Ｃｅｎｔｅｒ　Ｔｅｎｓｉｏｎ）が大きくなり過ぎ、ガラスが破壊するときに粉砕することがある。
　なお、ＣＳ及びＤＯＬの値は表面応力計により測定することができる。 With respect to the strength when the glass plate according to the present invention is reinforced, the surface compressive stress (CS) is preferably 600 to 1000 MPa, and more preferably 650 to 950 MPa. If it is less than 600 MPa, scratches are likely to occur on the surface of the glass, and there is a possibility that a practically sufficient strength cannot be obtained.
The compressive stress layer depth (DOL; Depth of Layer) is preferably 5 to 50 μm, and more preferably 7 to 40 μm. If the surface is less than 5 μm, if the surface of the glass is scratched, the depth of the scratch may exceed the DOL and the glass may be easily broken.
If CS is too large or DOL becomes too deep, the tensile stress value (CT; Center Tension) at the center of the glass becomes too large and may be crushed when the glass breaks.
The values of CS and DOL can be measured with a surface stress meter.
　ＵＶ耐性とは、低圧水銀ランプ等の短波長側のＵＶ光を照射した際に波長３００～８００ｎｍにおける透過率の低下を抑制することを意味する。
　短波長側のＵＶ照射は、波長１００～２８０ｎｍのＵＶを０．１～１０００ｍＷ／ｃｍ２で、１～２００００秒の照射時間の範囲内で実施される。処理コストを下げる側面からは、１～１００ｍＷ／ｃｍ２で、１２００秒以下の照射時間で実施することが好ましい。露光量としては、１０～１００００ｍＪ／ｃｍ２の条件で実施することが好ましく、５０～５０００ｍＪ／ｃｍ２の条件がより好ましい。光源として、主波長１８５ｎｍおよび２５４ｎｍの低圧水銀ランプや主波長１７２ｎｍのエキシマランプ等が挙げられる。この短波長側のＵＶ照射は、基板のＵＶ洗浄処理やＵＶ殺菌処理等に一般的に用いられるものである。つまり、太陽光起因のソラリゼーション耐性は成層圏によって吸収されない長波長領域のＵＶ照射に対する評価となることから、本発明における波長３００ｎｍ以下の評価とは別の評価である。 The UV resistance means that a decrease in transmittance at a wavelength of 300 to 800 nm is suppressed when short-wavelength UV light such as a low-pressure mercury lamp is irradiated.
The UV irradiation on the short wavelength side is carried out at a wavelength of 100 to 280 nm in a range of 0.1 to 1000 mW / cm 2 and an irradiation time of 1 to 20000 seconds. From the aspect of reducing the processing cost, it is preferable that the irradiation time is 1 to 100 mW / cm 2 and the irradiation time is 1200 seconds or less. The exposure preferably be carried out at the 10 ~ 10000mJ / cm 2 condition, more preferably of 50 ~ 5000mJ / cm 2 conditions. Examples of the light source include a low-pressure mercury lamp having main wavelengths of 185 nm and 254 nm, an excimer lamp having a main wavelength of 172 nm, and the like. This UV irradiation on the short wavelength side is generally used for UV cleaning treatment or UV sterilization treatment of a substrate. In other words, solarization resistance due to sunlight is an evaluation for UV irradiation in a long wavelength region that is not absorbed by the stratosphere, and thus is an evaluation different from the evaluation for wavelengths of 300 nm or less in the present invention.
　本発明に係るガラス板では、ＵＶ耐性として、短波長側のＵＶ照射前の波長３００～８００ｎｍにおける透過率をＴ０ａとし、照射条件Ａに基づいて照射した後の波長３００～８００ｎｍにおける透過率をＴ１ａとしたときの、以下の式で表される各波長におけるＵＶ誘起吸収Δαが０．０７以下であることが好ましく、０．０５以下であることがより好ましい。
　　　　　　　　Δα＝－ｌｎ（Ｔ１ａ／Ｔ０ａ）
　ここで、照射条件Ａとは、セン特殊光源製ＰＬ２１－２００を用いて２００Ｗの低圧水銀ランプ（ＥＵＶ２００ＧＳ－１４：主波長１８５ｎｍおよび２５４ｎｍ）の光をガラス板の表面から５ｃｍ離れた位置から６００秒間照射することをいう。 In the glass plate according to the present invention, as UV resistance, the transmittance at a wavelength of 300 to 800 nm before UV irradiation on the short wavelength side is T0 a, and the transmittance at a wavelength of 300 to 800 nm after irradiation based on the irradiation condition A is preferably when formed into a T1 a, the UV induced absorption Δα at each wavelength represented by the following formula is 0.07 or less, and more preferably 0.05 or less.
Δα = −ln (T1 a / T0 a )
Here, the irradiation condition A means that a PLW 21-200 made by Sen Special Light Source is used for 600 seconds from a position 5 cm away from the surface of the glass plate using a 200 W low-pressure mercury lamp (EUV200GS-14: main wavelengths 185 nm and 254 nm). Irradiation.
　ガラス板の波長３００～８００ｎｍにおける透過率は、例えば高圧水銀ランプを用いた主波長３６５ｎｍの長波長側のＵＶ照射前後では殆ど変化しない。しかしながら、従来の組成の化学強化ガラス板の場合、短波長側のＵＶ照射によって透過率が低下してしまう。また、透過率の低下度合いが波長によって一律でなく、波長に依存して低下率が変わる場合には、短波長側のＵＶ照射により透過率がより低くなった波長領域の色の補色に呈色してしまうため、色味が悪くなる。 The transmittance of a glass plate at a wavelength of 300 to 800 nm hardly changes before and after UV irradiation on the long wavelength side with a main wavelength of 365 nm using, for example, a high-pressure mercury lamp. However, in the case of a chemically strengthened glass plate having a conventional composition, the transmittance decreases due to UV irradiation on the short wavelength side. In addition, when the degree of transmittance decrease is not uniform depending on the wavelength, and the rate of decrease varies depending on the wavelength, the color is complementary to the color of the wavelength region in which the transmittance is lower due to UV irradiation on the short wavelength side. As a result, the color becomes worse.
　本発明におけるガラス組成を採用することにより、短波長側のＵＶ照射前後における波長３００～８００ｎｍにおける透過率の低下を抑制し、かつガラス板の色味が悪くなることを防ぐことができる。 By adopting the glass composition in the present invention, it is possible to suppress a decrease in transmittance at a wavelength of 300 to 800 nm before and after UV irradiation on the short wavelength side and to prevent the color of the glass plate from being deteriorated.
　上記ＵＶ耐性は、Ｆｅ２Ｏ３を０．０３５～０．１２％かつレドックス比を０．５５０未満とすることでより向上することができる。ＵＶ耐性がさらに向上する点から、Ｆｅ２Ｏ３は０．０５％以上が好ましく、０．１％以上がより好ましい。また、レドックス比は０．５００以下が好ましく、０．４５０以下がより好ましい。 The UV resistance can be further improved by making Fe 2 O 3 0.035 to 0.12% and the redox ratio less than 0.550. From the viewpoint of further improving the UV resistance, Fe 2 O 3 is preferably 0.05% or more, and more preferably 0.1% or more. The redox ratio is preferably 0.500 or less, and more preferably 0.450 or less.
　本明細書において、レドックス比とは、ガラス中に含まれる全鉄Ｆｅ量に対する２価の鉄Ｆｅ２＋の割合（原子比）をいう。レドックス比は、％単位で表示することがある。
　レドックス比の値は、溶融ガラス中に酸素を導入して２価の鉄Ｆｅ２＋を３価の鉄Ｆｅ３＋に酸化することによって適宜調整することができる。
　なお、レドックス比はガラス中のＦｅ２＋をビピリジル吸光光度法により定量し、全鉄Ｆｅ量の値をＩＣＰ発光分析法により定量する等の方法で求めることができる。なお全鉄量は、簡易的には蛍光Ｘ線によっても求めることができる。 In this specification, the redox ratio refers to the ratio (atomic ratio) of divalent iron Fe 2+ to the total iron Fe amount contained in the glass. The redox ratio may be expressed in%.
The value of the redox ratio can be appropriately adjusted by introducing oxygen into the molten glass and oxidizing the divalent iron Fe 2+ to the trivalent iron Fe 3+ .
The redox ratio can be determined by a method such as quantifying Fe 2+ in glass by bipyridyl absorptiometry and quantifying the value of total iron Fe by ICP emission analysis. Note that the total iron amount can also be obtained simply by fluorescent X-rays.
　本発明に係るガラス板は用途をディスプレイ用とする場合には、無色ガラスであることが好ましい。無色ガラスとは着色成分が２％以下であるガラスを意味し、波長３８０～７８０ｎｍにおける平均透過率が９１％以上であるガラスを言う。
　着色成分は１％以下が好ましく、０．５％以下がより好ましく、０．２％以下がさらに好ましく、実質的に含有しないことがことさらに好ましい。実質的に含有しないとは、不可避的不純物を除き含有しない意味である。
　波長３８０～７８０ｎｍにおける平均透過率は９１％以上が好ましく、９１．２％以上がより好ましく、９１．４％以上がさらに好ましい。 The glass plate according to the present invention is preferably colorless glass when used for a display. Colorless glass means glass having a coloring component of 2% or less, and glass having an average transmittance of 91% or more at a wavelength of 380 to 780 nm.
The coloring component is preferably 1% or less, more preferably 0.5% or less, further preferably 0.2% or less, and still more preferably substantially not contained. “Substantially not contained” means not containing any inevitable impurities.
The average transmittance at a wavelength of 380 to 780 nm is preferably 91% or more, more preferably 91.2% or more, and further preferably 91.4% or more.
　着色成分としては、ＭｐＯｑで表される成分が挙げられ、ＭはＣｏ、Ｃｕ、Ｖ、Ｃｒ、Ｐｒ、Ｃｅ、Ｂｉ、Ｅｕ、Ｍｎ、Ｅｒ、Ｎｉ、Ｎｄ、Ｗ、Ｒｂ、Ｓｎ及びＡｇからなる群より選ばれる少なくとも１種であり、ｐとｑは前記ＭとＯ（酸素原子）との原子比を表す。 Examples of the coloring component include a component represented by M p O q , where M is Co, Cu, V, Cr, Pr, Ce, Bi, Eu, Mn, Er, Ni, Nd, W, Rb, Sn, and It is at least one selected from the group consisting of Ag, and p and q represent the atomic ratio of M and O (oxygen atom).
　本発明に係るガラス板は、上記組成に加えて、効果を損なわない範囲で他の成分を含んでいてもよい。含んでいてもよい成分としては、ＳＯ３、ＺｎＯ２、ＺｒＯ２、ＴｉＯ２、ＳｒＯ、ＢａＯ、Ｌｉ２Ｏ、Ｃｓ２Ｏ、Ｆｒ２Ｏ、ＡｓＯ、ＳｂＯ、ＳｅＯ２等が挙げられる。
　これらは合計で０～２％含むことができる。 In addition to the above composition, the glass plate according to the present invention may contain other components as long as the effects are not impaired. Examples of the component that may be included include SO 3 , ZnO 2 , ZrO 2 , TiO 2 , SrO, BaO, Li 2 O, Cs 2 O, Fr 2 O, AsO, SbO, and SeO 2 .
These can be included in a total of 0 to 2%.
　ガラス板の厚さは全体で０．１～２ｍｍであればよく、０．２～１ｍｍが剛性と軽量性の両立の点から好ましい。 The total thickness of the glass plate may be 0.1 to 2 mm, and 0.2 to 1 mm is preferable from the viewpoint of achieving both rigidity and light weight.
　ガラス板を構成する各成分の組成範囲について以下に説明する。
　ＳｉＯ２は、ガラス微細構造の中で網目構造を形成する成分として知られており、ガラスを構成する主要成分である。ＳｉＯ２の含有量は、６０％以上であり、好ましくは６３％以上、より好ましくは６５％以上、特に好ましくは６７％以上である。また、ＳｉＯ２の含有量は、７５％以下であり、好ましくは７３％以下、より好ましくは７１％以下、特に好ましくは７０％以下である。ＳｉＯ２の含有量が６０％以上であるとガラスとしての安定性や耐候性の点で優位である。また、網目構造を形成することにより熱膨張の増大を抑制できる。一方、ＳｉＯ２の含有量が７５％以下であると、溶解性および成形性の点で優位である。 The composition range of each component constituting the glass plate will be described below.
SiO 2 is known as a component that forms a network structure in the glass microstructure, and is a main component constituting the glass. The content of SiO 2 is 60% or more, preferably 63% or more, more preferably 65% or more, particularly preferably at least 67%. The content of SiO 2 is 75% or less, preferably 73% or less, more preferably 71% or less, and particularly preferably 70% or less. When the content of SiO 2 is 60% or more, it is advantageous in terms of stability and weather resistance as glass. Moreover, an increase in thermal expansion can be suppressed by forming a network structure. On the other hand, when the content of SiO 2 is 75% or less, it is advantageous in terms of solubility and moldability.
　Ａｌ２Ｏ３は化学強化におけるイオン交換性能を向上させる作用があり、特にＣＳを向上する作用が大きい。ガラスの耐候性を向上する成分としても知られている。また、フロート法における成形時にボトム面からの錫の侵入を抑制する作用がある。さらに、ＳＯ２処理を行った際に脱アルカリを促進させる作用がある。 Al 2 O 3 has an effect of improving the ion exchange performance in chemical strengthening, and in particular, an effect of improving CS. It is also known as a component that improves the weather resistance of glass. Moreover, there exists an effect | action which suppresses the penetration | invasion of the tin from a bottom surface at the time of shaping | molding in a float glass process. Furthermore, there is an effect of promoting dealkalization when the SO 2 treatment is performed.
　Ａｌ２Ｏ３の含有量は、２％以上であり、好ましくは３％以上、より好ましくは４％以上である。また、Ａｌ２Ｏ３の含有量は、２５％以下であり、好ましくは２０％以下、より好ましくは１５％以下、さらに好ましくは９．５％以下、特に好ましくは８．６％以下である。Ａｌ２Ｏ３の含有量が２％以上であると、イオン交換によって所望のＣＳ値が得られ、また、フロート法に置いて、錫溶融バスに接している面（ボトム面）からの錫の侵入を抑制し化学強化時にガラスを反り難くする効果、水分量変化に対する安定性の効果、脱アルカリ促進効果が得られる。
　一方、Ａｌ２Ｏ３の含有量が２５％以下であると、ガラスの粘性が高い場合でも失透温度が大きくは上昇しないため、フロート設備での溶解、成形の点で優位である。 The content of Al 2 O 3 is 2% or more, preferably 3% or more, more preferably 4% or more. The content of Al 2 O 3 is 25% or less, preferably 20% or less, more preferably 15% or less, still more preferably 9.5% or less, and particularly preferably 8.6% or less. When the content of Al 2 O 3 is 2% or more, a desired CS value is obtained by ion exchange, and in addition to the float method, tin from the surface (bottom surface) in contact with the tin melting bath is obtained. The effect of suppressing intrusion and making the glass difficult to warp during chemical strengthening, the effect of stability against moisture content change, and the effect of promoting dealkalization are obtained.
On the other hand, when the content of Al 2 O 3 is 25% or less, the devitrification temperature does not increase greatly even when the viscosity of the glass is high, which is advantageous in terms of melting and forming in a float facility.
　Ｂ２Ｏ３は、ガラス原料の溶融を促進し、機械的特性や耐候性を向上させる成分であるが、揮発による脈理（ｒｅａｍ）の生成、炉壁の侵食等の不都合が生じないために６％以下の範囲で含有してもよい。Ｂ２Ｏ３を含有する場合は５％以下が好ましく、４％以下がより好ましく、実質的に含有しないことが特に好ましい。 B 2 O 3 is a component that promotes melting of the glass raw material and improves mechanical properties and weather resistance, but it does not cause inconveniences such as generation of striae due to volatilization and furnace wall erosion. You may contain in 6% or less of range. When it contains B 2 O 3 , it is preferably 5% or less, more preferably 4% or less, and particularly preferably not substantially contained.
　Ｎａ２Ｏはイオン交換により表面圧縮応力層を形成させる必須成分であり、ＤＯＬを深くする作用がある。また、ガラスの溶解温度と失透温度を下げ、ガラスの溶解性、成形性を向上させる成分である。Ｎａ２Ｏは非架橋酸素を生み出す成分であり、ガラス中の水分量が変動したときの化学強化特性の変動が少なくなる。
　Ｎａ２Ｏの含有量は、１０％以上であり、好ましくは１１％以上、より好ましくは１３％以上である。また、Ｎａ２Ｏの含有量は、２０％以下であり、好ましくは１８％以下、より好ましくは１６％以下である。Ｎａ２Ｏの含有量が１０％以上であると、イオン交換により所望の表面圧縮応力層を形成することができ、水分量変化に対する変動も抑えられる。
　一方、Ｎａ２Ｏの含有量が２０％以下であると、十分な耐候性が得られ、フロート法による成形時にボトム面からの錫の侵入量も抑制でき、化学強化処理後にガラスを反り難くすることができる。 Na 2 O is an essential component for forming a surface compressive stress layer by ion exchange, and has the effect of deepening the DOL. Moreover, it is a component which lowers | hangs the melting temperature and devitrification temperature of glass, and improves the meltability and moldability of glass. Na 2 O is a component that generates non-crosslinked oxygen, and the variation in chemical strengthening characteristics when the amount of moisture in the glass varies is reduced.
The content of Na 2 O is 10% or more, preferably 11% or more, more preferably 13% or more. Further, the content of Na 2 O is 20% or less, preferably 18% or less, more preferably 16% or less. When the content of Na 2 O is 10% or more, a desired surface compressive stress layer can be formed by ion exchange, and fluctuations due to changes in moisture content can be suppressed.
On the other hand, when the content of Na 2 O is 20% or less, sufficient weather resistance can be obtained, the amount of intrusion of tin from the bottom surface during molding by the float method can be suppressed, and the glass is hardly warped after chemical strengthening treatment. be able to.
　Ｋ２Ｏはイオン交換速度を増大しＤＯＬを深くし、ガラスの溶解温度を下げる効果があり、非架橋酸素を増大させる成分であるため、７％以下の範囲で含有してもよい。７％以下であるとＤＯＬが深くなりすぎず、また十分なＣＳが得られ、ガラスの溶解温度を下げることができる。Ｋ２Ｏを含有する場合は５％以下が好ましく、より好ましくは４％以下、さらに好ましくは２％以下である。一方で、少量のＫ２Ｏは、フロート法による成形時にボトム面からの錫の侵入量を抑制する効果があるため、フロート法により成形する際には含有することが好ましい。この場合、Ｋ２Ｏの含有量は０．０１％以上が好ましく、より好ましくは０．１％以上である。 K 2 O is an ingredient that increases the ion exchange rate, deepens the DOL, lowers the melting temperature of the glass, and increases non-crosslinked oxygen, so it may be contained in a range of 7% or less. If it is 7% or less, the DOL does not become too deep, sufficient CS is obtained, and the melting temperature of the glass can be lowered. Preferably 5% or less when they contain K 2 O, more preferably 4% or less, more preferably 2% or less. On the other hand, since a small amount of K 2 O has an effect of suppressing the amount of intrusion of tin from the bottom surface at the time of molding by the float process, it is preferably contained when molding by the float process. In this case, the content of K 2 O is preferably 0.01% or more, more preferably 0.1% or more.
　ＭｇＯは、ガラスを安定化させ、溶解性を向上させ、かつこれを添加することでアルカリ金属の含有量を低下させて熱膨張率（ＣＴＥ）の上昇を抑制することのできる成分である。ＭｇＯの含有量は、０．５％以上であり、好ましくは３％以上、より好ましくは５％以上である。また、ＭｇＯの含有量は、１０％以下であり、好ましくは９％以下、より好ましくは８％以下である。ＭｇＯの含有量が０．５％以上であると、ＣＴＥの上昇抑制効果を発揮する。一方、ＭｇＯの含有量が１０％以下であると、失透の起こりにくさが維持され、もしくは十分なイオン交換速度が得られる。 MgO is a component that can stabilize the glass, improve the solubility, and reduce the alkali metal content by adding this to suppress an increase in the coefficient of thermal expansion (CTE). The content of MgO is 0.5% or more, preferably 3% or more, more preferably 5% or more. Further, the content of MgO is 10% or less, preferably 9% or less, more preferably 8% or less. When the content of MgO is 0.5% or more, the CTE increase suppressing effect is exhibited. On the other hand, when the content of MgO is 10% or less, the difficulty of devitrification is maintained, or a sufficient ion exchange rate is obtained.
　ＣａＯは、ガラスを安定化させる成分であり、ＭｇＯの存在による失透を防止し、かつＣＴＥの上昇を抑制しながら溶解性を向上する効果を有する。ＣａＯの含有量は、０～１５％であり、好ましくは０．５～１２％、より好ましくは２～１０％である。ＣａＯの含有量が１５％以下であると、十分なイオン交換速度が得られ、所望のＤＯＬが得られる。また、化学強化におけるイオン交換性能を特段に向上させたい場合には、ＣａＯは５％未満が好ましく、より好ましくは４％以下である。 CaO is a component that stabilizes the glass, and has the effect of improving the solubility while preventing devitrification due to the presence of MgO and suppressing an increase in CTE. The content of CaO is 0 to 15%, preferably 0.5 to 12%, more preferably 2 to 10%. When the content of CaO is 15% or less, a sufficient ion exchange rate is obtained, and a desired DOL is obtained. Moreover, when it is desired to particularly improve the ion exchange performance in chemical strengthening, CaO is preferably less than 5%, more preferably 4% or less.
　ＣａＯ／ＭｇＯ（質量比）は、化学強化におけるイオン交換性能を向上させ、ガラス板の透過率を高める観点から、１．５以下であることが好ましい。より好ましくは０．１～１．２、さらに好ましくは０．２～１．０である。
　この他、ガラスの溶融の清澄剤としてＳＯ３、塩化物、フッ化物などを０～１％の範囲で適宜含有してもよい。 CaO / MgO (mass ratio) is preferably 1.5 or less from the viewpoint of improving ion exchange performance in chemical strengthening and increasing the transmittance of the glass plate. More preferably, it is 0.1 to 1.2, and still more preferably 0.2 to 1.0.
In addition, SO 3 , chlorides, fluorides and the like may be appropriately contained in the range of 0 to 1% as glass refining agents.
　本明細書においてガラス板のＦｅ２＋の吸収係数αＦｅ２＋とは、波長７８０ｎｍにおける吸収をゼロとみなし、以下の式に従い求めることができる。ここで波長７８０ｎｍにおける吸収をゼロとみなして基準にするのは、ガラス板の反射の影響を差し引くためである。
　　　αＦｅ２＋＝２．３０３×ｌｏｇ（Ｔ７８０／Ｔｉ）／ｄ
　　　Ｔｉ：測定波長の透過率（％）
　　　Ｔ７８０：波長７８０ｎｍにおける透過率（％）
　　　ｄ：ガラスの厚み（ｃｍ）
　なお、Ｔｉにおける測定波長は波長３８０～７８０ｎｍとする。 Absorption coefficient alpha Fe @ 2 + and is of Fe 2+ of the glass plate in the present specification, the absorption at a wavelength of 780nm regarded as zero, may be determined according to the following equation. Here, the reason why the absorption at the wavelength of 780 nm is regarded as zero and used as a reference is to subtract the influence of the reflection of the glass plate.
α Fe2 + = 2.303 × log ( T 780 / Ti) / d
Ti: Transmittance of measurement wavelength (%)
T780 : Transmittance (%) at a wavelength of 780 nm
d: Glass thickness (cm)
The measurement wavelength for Ti is 380 to 780 nm.
　ＵＶ照射ガラス板のＦｅ２＋の吸収係数や透過率は、照射されたＵＶの照射時間や照射強度によって異なる。そのため、ガラス板の特性をムラなく評価するために、ＵＶ照射ガラス板を表面から深さ方向に１５０μｍ研磨した後に、再度照射条件ＡでＵＶを照射してＦｅ２＋の吸収係数や透過率の測定を行う。表面から深さ方向に１５０μｍ研磨した後のガラス板のＦｅ２＋の吸収係数は、ＵＶ未照射のガラス板のＦｅ２＋の吸収係数と同程度の値となることから、研磨後のガラス板をＵＶ未照射のガラス板とみなすことができる。 The absorption coefficient and transmittance of Fe 2+ of the UV-irradiated glass plate vary depending on the irradiation time and irradiation intensity of the irradiated UV. Therefore, in order to uniformly evaluate the characteristics of the glass plate, after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 μm, UV irradiation is again performed under the irradiation condition A to measure the absorption coefficient and transmittance of Fe 2+. I do. Since the absorption coefficient of Fe 2+ of the glass plate after polishing 150 μm in the depth direction from the surface is the same value as the absorption coefficient of Fe 2+ of the glass plate not irradiated with UV, the glass plate after polishing is UV-treated. It can be regarded as an unirradiated glass plate.
　実工程では前記照射条件Ａに比べて短い照射時間や弱い照射強度が使われる場合も多く、研磨後（ＵＶ未照射に相当）のＦｅ２＋の吸収係数は、研磨前（実工程でのＵＶ照射後）のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きくなる。
　本発明に係るＵＶ照射ガラス板は、前記研磨に次いで照射条件ＡでＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さいことが好ましく、０．０１９ｃｍ－１以上小さいことがより好ましい。 In an actual process, a shorter irradiation time and a lower irradiation intensity are often used compared to the irradiation condition A, and the absorption coefficient of Fe 2+ after polishing (corresponding to UV non-irradiation) is the same as that before polishing (UV irradiation in the actual process). The absorption coefficient of Fe 2+ after) is 0.001 cm −1 or more.
In the UV-irradiated glass plate according to the present invention, the absorption coefficient of Fe 2+ after irradiation with UV under irradiation condition A following the polishing is 0.017 cm −1 or more smaller than the absorption coefficient of Fe 2+ before irradiation. Is preferable, and it is more preferably 0.019 cm −1 or less.
　ガラスの表層部分でＦｅ２＋→Ｆｅ３＋の反応が起こると、Ｆｅ２＋の存在に由来するガラス構造の欠陥生成が抑制され、ＵＶ耐性が向上するものと考えられる。
　本発明に係るガラス板において、短波長側のＵＶ照射後のＦｅ２＋の吸収係数がＵＶ照射前のＦｅ２＋の吸収係数よりも小さいことは、ガラス板の表層部分で上記Ｆｅ２＋→Ｆｅ３＋の反応が起こっていることを示している。十分なＵＶ耐性向上の効果を得るためには、ＵＶ照射後のＦｅ２＋の吸収係数は、ＵＶ照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さいことが好ましい。 When the reaction of Fe 2+ → Fe 3+ occurs in the surface layer portion of the glass, it is considered that the generation of defects in the glass structure due to the presence of Fe 2+ is suppressed and the UV resistance is improved.
In the glass plate according to the present invention, the absorption coefficient of the Fe 2+ after UV irradiation of the short wavelength side is smaller than the absorption coefficient of the Fe 2+ before UV irradiation, the surface layer portion of the glass plate of the Fe 2+ → Fe 3+ Indicates that a reaction is taking place. In order to obtain a sufficient effect of improving UV resistance, the absorption coefficient of Fe 2+ after UV irradiation is preferably 0.017 cm −1 or more smaller than the absorption coefficient of Fe 2+ before UV irradiation.
　また、上記研磨に代えて、徐冷処理を行ってもよい。すなわち、一定の条件下で徐冷処理を行った後のガラス板のＦｅ２＋の吸収係数は、ＵＶ未照射のガラス板のＦｅ２＋の吸収係数と同程度の値となることから、徐冷処理後のガラス板をＵＶ未照射のガラス板とみなすことができる。 In addition, a slow cooling process may be performed instead of the above polishing. That is, since the absorption coefficient of Fe 2+ of the glass plate after performing the slow cooling treatment under a certain condition is the same value as the absorption coefficient of Fe 2+ of the glass plate not irradiated with UV, the slow cooling treatment The latter glass plate can be regarded as a glass plate not irradiated with UV.
　実工程では前記照射条件Ａに比べて短い照射時間や弱い照射強度が使われる場合も多く、徐冷処理後（ＵＶ未照射に相当）のＦｅ２＋の吸収係数は、徐冷処理前（実工程でのＵＶ照射後）のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きくなる。
　具体的な徐冷処理としては、ＵＶ照射ガラス板を（Ｔｇ＋４０）℃の温度で１時間保持し、１℃／分の冷却速度で室温まで徐冷する。 In the actual process, a shorter irradiation time and a lower irradiation intensity are often used compared to the irradiation condition A, and the absorption coefficient of Fe 2+ after the slow cooling process (corresponding to UV non-irradiation) is the same as that before the slow cooling process (actual process). larger 0.001 cm -1 or more than the absorption coefficient of the Fe 2+ after UV irradiation) in.
As a specific slow cooling treatment, the UV-irradiated glass plate is held at a temperature of (Tg + 40) ° C. for 1 hour and slowly cooled to room temperature at a cooling rate of 1 ° C./min.
　本発明に係るＵＶ照射ガラス板は、前記徐冷処理に次いで照射条件ＡでＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さいことが好ましく、０．０１９ｃｍ－１以上小さいことがより好ましい。 In the UV-irradiated glass plate according to the present invention, the absorption coefficient of Fe 2+ after irradiation with UV under irradiation condition A following the slow cooling treatment is 0.017 cm −1 or more than the absorption coefficient of Fe 2+ before irradiation. It is preferably small, more preferably 0.019 cm −1 or more.
　Ｆｅ２＋の吸収係数と同様に、透過率においても、ＵＶ照射ガラス板に対して上記研磨または徐冷処理を行うことにより、ＵＶ未照射のガラス板とみなすことができる。
　実工程では前記照射条件Ａに比べて短い照射時間や弱い照射強度が使われる場合も多く、研磨または徐冷処理後（ＵＶ未照射に相当）の透過率Ｔ０’またはＴ０’’と、研磨または徐冷処理前（実工程でのＵＶ照射後）の透過率Ｔ１’またはＴ１’’とが－ｌｎ（Ｔ１’／Ｔ０’）≧０．００１または－ｌｎ（Ｔ１’’／Ｔ０’’）≧０．００１の関係を満たすこととなる。 Similar to the absorption coefficient of Fe 2+ , the transmittance can be regarded as a glass plate not irradiated with UV by performing the above polishing or slow cooling treatment on the UV irradiated glass plate.
In an actual process, a shorter irradiation time or a lower irradiation intensity is often used compared to the irradiation condition A, and the transmittance T0 ′ or T0 ″ after polishing or annealing (corresponding to UV non-irradiation) and polishing or The transmittance T1 ′ or T1 ″ before annealing (after UV irradiation in the actual process) is −ln (T1 ′ / T0 ′) ≧ 0.001 or −ln (T1 ″ / T0 ″) ≧ The relationship of 0.001 is satisfied.
　本発明に係るＵＶ照射ガラス板は、前記研磨または徐冷処理に次いで照射条件ＡでＵＶを照射した後の透過率Ｔ１ｂと、ＵＶ照射前の透過率Ｔ０ｂとが－ｌｎ（Ｔ１ｂ／Ｔ０ｂ）≦０．０７の関係を満たすことが好ましく、０．０５以下となることがより好ましい。 The UV-irradiated glass plate according to the present invention has a transmittance T1 b after irradiation with UV under irradiation condition A following the polishing or annealing process and a transmittance T0 b before UV irradiation of −ln (T1 b / It is preferable to satisfy the relationship of T0 b ) ≦ 0.07, and more preferably 0.05 or less.
　ここでの透過率Ｔｎｂ、Ｔｎ’及びＴｎ’’並びに先述したＴｎａ（ｎは０または１）はいずれも波長３００～８００ｎｍにおける透過率であり、透過率Ｔ１ａ及びＴ１ｂは前記照射条件ＡでＵＶが照射された後の透過率である。 Here, the transmittances Tn b , Tn ′ and Tn ″ and the above-described Tn a (n is 0 or 1) are all transmittances at wavelengths of 300 to 800 nm, and the transmittances T1 a and T1 b are the irradiation conditions described above. A transmittance after UV irradiation with A.
　本発明に係るガラス板のガラス転移温度（Ｔｇ）は、例えば５３０℃以上であり、５４０℃以上であることが好ましく、５５０℃以上であることがより好ましく、５５０～６００℃であることがさらに好ましい。Ｔｇが５３０℃以上であることにより、化学強化処理時の応力緩和の抑制、熱反りの抑制等の点で有利となる。
　Ｔｇの調整は、ＳｉＯ２、Ａｌ２Ｏ３の総量とアルカリ金属酸化物およびアルカリ土類酸化物の量を調整すること等により可能である。 The glass transition temperature (Tg) of the glass plate according to the present invention is, for example, 530 ° C. or more, preferably 540 ° C. or more, more preferably 550 ° C. or more, and further preferably 550 to 600 ° C. preferable. When Tg is 530 ° C. or higher, it is advantageous in terms of suppression of stress relaxation and thermal warpage during chemical strengthening treatment.
Tg can be adjusted by adjusting the total amount of SiO 2 and Al 2 O 3 and the amount of alkali metal oxide and alkaline earth oxide.
　本発明に係るガラス板の熱膨張率ＣＴＥは、５０～３５０℃の温度範囲において、例えば８０×１０－７～１００×１０－７／Ｋであり、好ましくは８０×１０－７～９５×１０－７／Ｋである。ＣＴＥが８０×１０－７／Ｋ以上であることにより、金属や他の物質との熱膨張マッチングの点で有利となる。またＣＴＥの調整は、アルカリ金属酸化物およびアルカリ土類酸化物の量を調整すること等により可能である。 The thermal expansion coefficient CTE of the glass plate according to the present invention is, for example, 80 × 10 −7 to 100 × 10 −7 / K, preferably 80 × 10 −7 to 95 × 10 in the temperature range of 50 to 350 ° C. -7 / K. When the CTE is 80 × 10 −7 / K or more, it is advantageous in terms of thermal expansion matching with metals and other substances. CTE can be adjusted by adjusting the amount of alkali metal oxide and alkaline earth oxide.
　本発明に係るガラス板の室温での密度は、通常のソーダライムガラスと同一のフロート設備で交互に生産することを考えると、ソーダライムガラスとの密度の差を小さくする観点から、２．３８～２．５４ｇ／ｃｍ３であり、好ましくは２．４０～２．５２ｇ／ｃｍ３であることが好ましい。 The density at room temperature of the glass plate according to the present invention is 2.38 from the viewpoint of reducing the difference in density from soda lime glass, considering that it is alternately produced in the same float equipment as normal soda lime glass. To 2.54 g / cm 3 , preferably 2.40 to 2.52 g / cm 3 .
＜ガラス板の製造方法＞
　本発明に係るＵＶ照射用ガラス板の製造方法は特に限定されず、溶融ガラスを板状のガラス板に成形する方法は特に限定されない。例えば、種々の原料を適量調合し、約１５００～１６００℃に加熱し溶融した後、脱泡、攪拌等により均質化し、周知のフロート法、ダウンドロー法（フュージョン法等）、プレス法等によって板状に、またはキャストしてブロック状に成形し、徐冷後所望のサイズに切断し、ガラス板が製造される。必要に応じて研磨加工を施すが、研磨加工に加えてまたは研磨加工に代えて、ガラス板表面をフッ素剤で処理することも可能である。 <Method for producing glass plate>
The manufacturing method of the glass plate for UV irradiation which concerns on this invention is not specifically limited, The method of shape | molding molten glass into a plate-shaped glass plate is not specifically limited. For example, appropriate amounts of various raw materials are prepared, heated to about 1500-1600 ° C and melted, and then homogenized by defoaming, stirring, etc., and the plate is obtained by a well-known float method, downdraw method (fusion method, etc.), press method, etc. Or cast into a block shape, and after slow cooling, cut into a desired size to produce a glass plate. A polishing process is performed as necessary, but it is also possible to treat the glass plate surface with a fluorine agent in addition to or instead of the polishing process.
　製造後のガラス板がＳｉＯ２を６０～７５％、Ａｌ２Ｏ３を２～２５％、Ｎａ２Ｏを１０～２０％、Ｋ２Ｏを０～７％、ＭｇＯを０．５～１０％、ＣａＯを０～１５％及びＦｅ２Ｏ３を０．０３５～０．１２％含有し、かつＣａＯ／ＭｇＯ（質量比）が１．５以下となるように原料を選択する。
　得られたＵＶ照射用ガラス板に短波長側のＵＶを照射することで、本発明にかかるＵＶ照射ガラス板が得られる。 The glass plate after production is SiO 2 60-75%, Al 2 O 3 2-25%, Na 2 O 10-20%, K 2 O 0-7%, MgO 0.5-10% The raw materials are selected so that 0-15% of CaO and 0.035-0.12% of Fe 2 O 3 are contained, and CaO / MgO (mass ratio) is 1.5 or less.
The UV irradiation glass plate concerning this invention is obtained by irradiating UV of the short wavelength side to the obtained glass plate for UV irradiation.
　製造されたガラスを所望のサイズに切断してガラス板とした後、該ガラス板を４００℃程度に予熱し、溶融塩内でガラス板表面のＮａと溶融塩内のＫとをイオン交換することで化学強化処理を行うことが好ましい。
　また、特定の塩を含む溶融塩内でイオン交換した後に、酸処理およびアルカリ処理を行うことで、さらに高強度の化学強化ガラス板としてもよい。 After the produced glass is cut to a desired size to obtain a glass plate, the glass plate is preheated to about 400 ° C., and ion exchange is performed between Na on the surface of the glass plate and K in the molten salt in the molten salt. It is preferable to perform a chemical strengthening treatment.
Further, after ion exchange in a molten salt containing a specific salt, an acid treatment and an alkali treatment may be performed to obtain a chemically strengthened glass plate having higher strength.
　得られたガラス板のＣＳは６００～１０００ＭＰａが好ましく、６５０～９５０ＭＰａがより好ましい。ＣＳの調整は、イオン交換に用いる溶融硝酸カリウム塩中のＮａ濃度、強化時間および溶融塩温度を調整することにより可能である。より高いＣＳを得るためには、溶融硝酸カリウム塩中のＮａ濃度を低減する。具体的には、Ｎａ濃度は３質量％以下が好ましく、２．５質量％以下であることがより好ましく、１質量％以下であることがさらに好ましい。
　またＤＯＬは５～５０μｍが好ましく、７～４０μｍがより好ましい。ＤＯＬの調整は、イオン交換に用いる溶融硝酸カリウム塩中のＮａ濃度、強化時間および溶融塩温度を調整することにより可能である。より高いＤＯＬを得るためには、溶融塩の温度を上げる。具体的には、溶融塩の温度は４００℃以上であることが好ましく、より好ましくは４２０℃以上、さらに好ましくは４３０℃以上である。 The obtained glass plate preferably has a CS of 600 to 1000 MPa, more preferably 650 to 950 MPa. CS can be adjusted by adjusting Na concentration, strengthening time and molten salt temperature in the molten potassium nitrate salt used for ion exchange. In order to obtain higher CS, the Na concentration in the molten potassium nitrate is reduced. Specifically, the Na concentration is preferably 3% by mass or less, more preferably 2.5% by mass or less, and further preferably 1% by mass or less.
The DOL is preferably 5 to 50 μm, more preferably 7 to 40 μm. DOL can be adjusted by adjusting Na concentration, strengthening time and molten salt temperature in the molten potassium nitrate salt used for ion exchange. In order to obtain a higher DOL, the temperature of the molten salt is increased. Specifically, the temperature of the molten salt is preferably 400 ° C or higher, more preferably 420 ° C or higher, and further preferably 430 ° C or higher.
　本実施形態のガラス板は、化学強化後に切断することが可能である。切断方法は、通常のホイールチップカッターによるスクライブとブレイクを適用することが可能であり、レーザーによる切断も可能である。ガラス強度を維持するため、切断後に切断エッジの面取り加工を施してもよい。面取りは、機械的な研削加工でもよいし、フッ酸等の薬液で処理する方法を用いることもできる。 The glass plate of this embodiment can be cut after chemical strengthening. As a cutting method, scribing and breaking with a normal wheel tip cutter can be applied, and laser cutting is also possible. In order to maintain the glass strength, the cutting edge may be chamfered after cutting. The chamfering may be a mechanical grinding process or a method of treating with a chemical solution such as hydrofluoric acid.
　以下に実施例を挙げ、本発明を具体的に説明するが、本発明はこれらに限定されない。＜ガラス板の製造；試験例１～７＞
　下記表１の酸化物基準の質量百分率表示で示す組成になるように、一般に使用されているガラス原料および試薬を適宜選択し、ガラスとして５００ｇとなるように秤量した。秤量した原料を混合し、白金製るつぼに入れ、１６００℃の抵抗加熱式電気炉に投入し、３時間溶融し、脱泡、均質化した。
　得られたガラスを型材に流し込み、（Ｔｇ＋５０）℃の温度で１時間保持した後、０．５℃／分の速度で室温まで冷却し、ＵＶ照射用ガラス板を得た。デジタルマイクロメーターによって測定したガラス板の板厚を表１の「板厚（ｍｍ）」に示す。 EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. <Production of glass plate; Test Examples 1 to 7>
Generally used glass raw materials and reagents were appropriately selected so as to have a composition represented by mass percentage display based on oxides in Table 1 below, and weighed so as to give 500 g as glass. The weighed raw materials were mixed, put in a platinum crucible, put in a resistance heating electric furnace at 1600 ° C., melted for 3 hours, defoamed and homogenized.
The obtained glass was poured into a mold material and held at a temperature of (Tg + 50) ° C. for 1 hour, and then cooled to room temperature at a rate of 0.5 ° C./min to obtain a glass plate for UV irradiation. The thickness of the glass plate measured with a digital micrometer is shown in “plate thickness (mm)” in Table 1.
＜ガラス組成＞
　得られたガラス板の組成は蛍光Ｘ線法により同定を行った。レドックス比はガラス中のＦｅ２＋をビピリジル吸光光度法により定量し、全Ｆｅ量の値をＩＣＰ発光分光分析法で定量して求めた。これらの結果を表１に示す。 <Glass composition>
The composition of the obtained glass plate was identified by the fluorescent X-ray method. The redox ratio was determined by quantifying Fe 2+ in the glass by bipyridyl absorptiometry and quantifying the value of total Fe by ICP emission spectrometry. These results are shown in Table 1.
＜ＵＶ耐性＞
　ＵＶ照射用ガラス板に照射条件ＡでＵＶを照射、すなわち低圧水銀ランプ（主波長１８５ｎｍおよび２５４ｎｍ）の光を５ｃｍ離れた位置から６００秒照射した後、ＵＶ照射ガラス板の波長２００～２５００ｎｍにおける透過率を測定した。透過率は日立ハイテクノロジーズ社製の分光光度計商品名Ｕ－４１００により、波長１ｎｍ刻みで測定した。
　光照射前の波長３００～８００ｎｍにおける透過率をＴ０ａとし、光照射後の波長３００～８００ｎｍにおける透過率をＴ１ａとしたときの、以下の式で表される各波長におけるＵＶ誘起吸収Δαを算出した。
　　Δα＝－ｌｎ（Ｔ１ａ／Ｔ０ａ） <UV resistance>
The UV irradiation glass plate is irradiated with UV under irradiation condition A, that is, the light of a low-pressure mercury lamp (main wavelengths 185 nm and 254 nm) is irradiated for 600 seconds from a position 5 cm away, and then transmitted through the UV irradiation glass plate at a wavelength of 200 to 2500 nm. The rate was measured. The transmittance was measured in steps of 1 nm with a spectrophotometer trade name U-4100 manufactured by Hitachi High-Technologies Corporation.
UV-induced absorption Δα at each wavelength represented by the following formula, where T0 a is the transmittance at a wavelength of 300 to 800 nm before light irradiation, and T1 a is the transmittance at a wavelength of 300 to 800 nm after light irradiation. Calculated.
Δα = −ln (T1 a / T0 a )
　ＵＶ耐性試験の結果を表１に示す。表１中、「Δα（ＵＶ耐性）」は光照射前後でＵＶ誘起吸収の差が一番大きかった波長におけるＵＶ誘起吸収Δαの値を示す。また「Δα（ＵＶ耐性）　判定」において「○」とは、光照射前後でＵＶ誘起吸収の差が一番大きかった波長における、ＵＶ誘起吸収Δαが０．０７以下であったことを表し、「×」とは該ＵＶ誘起吸収Δαが０．０７より大きかったことを表す。 Table 1 shows the results of the UV resistance test. In Table 1, “Δα (UV resistance)” indicates the value of UV-induced absorption Δα at a wavelength where the difference in UV-induced absorption was the largest before and after light irradiation. In the “Δα (UV resistance) determination”, “◯” indicates that the UV-induced absorption Δα was 0.07 or less at the wavelength where the difference in UV-induced absorption was the largest before and after light irradiation. “X” means that the UV-induced absorption Δα was larger than 0.07.
＜レドックス比＞
　得られたガラスを粉砕し、ＨＦ水溶液にて溶解し、試験液体を作製した。この試験液体と、２，２’－ジピリジル溶液と、酢酸アンモニウム溶液とを混合して発色させ、その吸光ピーク強度を測定し、事前に作成した検量線を基にＦｅ２＋量を算出した。また、上記の試験液体と、ヒドロキシルアミン塩酸溶液と、２，２’－ジピリジル溶液と、酢酸アンモニウム溶液とを混合して全ての鉄を２価の鉄に還元して発色させ、その吸光ピーク強度を測定し、全鉄量を算出する。Ｆｅ２＋量と全鉄Ｆｅの比（レドックス比）を求め、表１の「Ｒｅｄｏｘ」欄に％で示した。 <Redox ratio>
The obtained glass was pulverized and dissolved in an HF aqueous solution to prepare a test liquid. The test liquid, a 2,2′-dipyridyl solution, and an ammonium acetate solution were mixed to develop color, the absorption peak intensity was measured, and the Fe 2+ amount was calculated based on a calibration curve prepared in advance. In addition, the above test liquid, hydroxylamine hydrochloric acid solution, 2,2'-dipyridyl solution, and ammonium acetate solution were mixed to reduce the color of all iron to divalent iron, and the absorbance peak intensity. To calculate the total iron content. The ratio (redox ratio) between the amount of Fe 2+ and the total iron Fe was determined and indicated in% in the “Redox” column of Table 1.
＜透過率＞
　前記＜ＵＶ耐性＞試験において、ガラス板の波長３８０～７８０ｎｍにおける平均透過率を、照射条件Ａでの光（ＵＶ）照射前と照射後の各々について求めた。結果を表１の「光照射前の透過率（％）」及び「光照射後の透過率（％）」に示す。また表１中、「光照射前の透過率　判定」が「○」とは光照射前の波長３８０～７８０ｎｍにおける平均透過率が９１％以上であったことを表し、「×」とは該平均透過率が９１％未満であったことを表す。 <Transmissivity>
In the <UV resistance> test, the average transmittance of the glass plate at a wavelength of 380 to 780 nm was determined for each of light (UV) irradiation under irradiation condition A and after irradiation. The results are shown in “Transmittance before light irradiation (%)” and “Transmittance after light irradiation (%)” in Table 1. Also, in Table 1, “Transmittance judgment before light irradiation” is “◯” means that the average transmittance at a wavelength of 380 to 780 nm before light irradiation is 91% or more, and “×” means the average It represents that the transmittance was less than 91%.
＜効果の指標＞
　照射条件ＡでのＵＶ照射前後のガラス板におけるＦｅ２＋の吸収係数をそれぞれ「光照射前Ｆｅ２＋吸収係数（ｃｍ－１）」、「光照射後Ｆｅ２＋吸収係数（ｃｍ－１）」として表１に示す。
　表１中、「Ｆｅ２＋の効果　判定」が「○」とは、ＵＶ照射後のＦｅ２＋の吸収係数がＵＶ照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さかったことを示し、「×」とは該吸収係数の変化がそれ以外であったことを示す。 <Indicator of effect>
The absorption coefficient of Fe 2+ in the glass plate before and after UV irradiation under irradiation condition A is expressed as “Fe 2+ absorption coefficient (cm −1 ) before light irradiation” and “Fe 2+ absorption coefficient (cm −1 ) after light irradiation”, respectively. It is shown in 1.
In Table 1, the term "effective determination of Fe 2+" is "○" indicates that the absorption coefficient of the Fe 2+ after UV irradiation was 0.017 cm -1 or less than the absorption coefficient of the Fe 2+ before UV irradiation "X" indicates that the change in the absorption coefficient was other than that.
　また、先述したとおり、ＵＶ照射ガラス板の表面を深さ方向に１５０μｍ研磨した後の研磨ガラス板のＦｅ２＋吸収係数（ｃｍ－１）は、ＵＶ未照射のガラス板（ＵＶ照射用ガラス板）のＦｅ２＋吸収係数（ｃｍ－１）と同程度の値になる。すなわち、ＵＶ照射ガラス板を研磨した後のＦｅ２＋吸収係数（ｃｍ－１）は表１における「光照射前Ｆｅ２＋吸収係数（ｃｍ－１）」と同程度の値となり、ＵＶ照射ガラス板を研磨した後のＦｅ２＋吸収係数（ｃｍ－１）は、研磨前のＦｅ２＋吸収係数（ｃｍ－１）よりも０．００１ｃｍ－１以上大きくなる。
　また、ＵＶ照射ガラス板を研磨した後に照射条件ＡでＵＶ照射した後のＦｅ２＋吸収係数（ｃｍ－１）は、表１における「光照射後Ｆｅ２＋吸収係数（ｃｍ－１）」と同程度の値になる。 Further, as described above, the Fe 2+ absorption coefficient (cm −1 ) of the polished glass plate after polishing the surface of the UV irradiated glass plate in the depth direction by 150 μm is the glass plate not irradiated with UV (glass plate for UV irradiation). The same value as the Fe 2+ absorption coefficient (cm −1 ). That is, the Fe 2+ absorption coefficient (cm −1 ) after polishing the UV-irradiated glass plate becomes the same value as “Fe 2+ absorption coefficient (cm −1 ) before light irradiation” in Table 1, and the UV-irradiated glass plate The Fe 2+ absorption coefficient (cm −1 ) after polishing is 0.001 cm −1 or more larger than the Fe 2+ absorption coefficient (cm −1 ) before polishing.
Further, the Fe 2+ absorption coefficient (cm −1 ) after the UV irradiation glass plate was polished and irradiated with UV under the irradiation condition A was almost the same as “Fe 2+ absorption coefficient (cm −1 ) after light irradiation” in Table 1. Value.
　表１にはＵＶ照射用ガラス板に照射条件ＡでＵＶを照射した前後における波長３００～８００ｎｍにおける透過率Ｔ０ａ及びＴ１ａを用いて導かれる－ｌｎ（Ｔ１ａ／Ｔ０ａ）の値を「Δα（ＵＶ耐性）」として示すが、Ｆｅ２＋吸収係数と同様の理由により、光照射状態にあったＵＶ照射ガラス板（透過率Ｔ１’）の表面を深さ方向に１５０μｍ研磨した後の研磨ガラス板の透過率Ｔ０’（＝Ｔ０ｂ）はＵＶ照射前のガラス板（ＵＶ照射用ガラス板）における透過率Ｔ０ａと同程度の値となる。すなわち、ＵＶ照射ガラス板を研磨した後の透過率Ｔ０’と研磨前の透過率Ｔ１’を用いて導かれる－ｌｎ（Ｔ１’／Ｔ０’）の値は０．００１以上となる。
　またＵＶ照射ガラス板を研磨した後に照射条件ＡでＵＶ照射した後の透過率Ｔ１ｂは、ＵＶ照射用ガラス板に照射条件ＡでＵＶを照射した後の透過率Ｔ１ａと同程度の値となる。そのため、ＵＶ照射ガラス板の研磨後に照射条件ＡでＵＶを照射した前後の透過率から算出される－ｌｎ（Ｔ１ｂ／Ｔ０ｂ）の値は、表１の「Δα（ＵＶ耐性）」で表される－ｌｎ（Ｔ１ａ／Ｔ０ａ）の値と同程度となる。 Table 1 shows the value of −ln (T1 a / T0 a ) derived by using the transmittances T0 a and T1 a at wavelengths of 300 to 800 nm before and after the UV irradiation glass plate was irradiated with UV under the irradiation condition A. “Δα (UV resistance)”, but for the same reason as the Fe 2+ absorption coefficient, the polished glass after polishing the surface of the UV-irradiated glass plate (transmittance T1 ′) in the light irradiation state in the depth direction by 150 μm The transmittance T0 ′ (= T0 b ) of the plate is approximately the same as the transmittance T0 a of the glass plate before UV irradiation (glass plate for UV irradiation). That is, the value of −ln (T1 ′ / T0 ′) derived by using the transmittance T0 ′ after polishing the UV-irradiated glass plate and the transmittance T1 ′ before polishing is 0.001 or more.
Further, the transmittance T1 b after the UV irradiation glass plate is irradiated with UV under the irradiation condition A after polishing the UV irradiation glass plate is similar to the transmittance T1 a after the UV irradiation glass plate is irradiated with the UV under the irradiation condition A. Become. Therefore, the value of −ln (T1 b / T0 b ) calculated from the transmittance before and after UV irradiation under irradiation condition A after polishing the UV-irradiated glass plate is represented by “Δα (UV resistance)” in Table 1. This is approximately the same as the value of −ln (T1 a / T0 a ).
　ＵＶ照射ガラス板を（Ｔｇ＋４０）℃で１時間保持し、１℃／分の冷却速度で室温まで徐冷する処理を行ったガラス板のＦｅ２＋の吸収係数及び透過率は、ＵＶ照射ガラス板を前記研磨処理したものと同じとみなすことができる。すなわち、該徐冷処理後のガラス板は光照射前のＵＶ照射用ガラス板のＦｅ２＋の吸収係数及び透過率と同程度の値となる。したがって、ガラス板の表面研磨が困難な場合は、前記徐冷処理を行っても同じ結果を得ることが出来る。 The UV irradiating glass plate was held at (Tg + 40) ° C. for 1 hour, and the glass plate treated with gradual cooling to room temperature at a cooling rate of 1 ° C./min was subjected to the absorption coefficient and transmittance of Fe 2+. It can be considered that it is the same as the said grinding | polishing process. That is, the glass plate after the slow cooling treatment has values similar to the absorption coefficient and transmittance of Fe 2+ of the glass plate for UV irradiation before light irradiation. Therefore, when it is difficult to polish the surface of the glass plate, the same result can be obtained even if the slow cooling treatment is performed.
＜熱膨張率＞
　熱膨張率（ＣＴＥ）はＪＩＳ　Ｒ　１６１８：２００２にもとづき、熱膨張計（ブルカー・エイエックス社製、ＴＤ５０００ＳＡ）を用いて５℃／分の昇温速度で測定し５０～３５０℃の平均線膨張率を求めた。また、得られた熱膨張曲線からガラス転移温度（Ｔｇ）を求めた。結果を表１の「Ｔｇ（℃）」及び「ＣＴＥ（×１０－７／Ｋ）」にそれぞれ示す。
　ガラス板の密度はアルキメデス法で測定した。結果を表１の「密度（ｇ／ｃｍ３）」に示す。 <Coefficient of thermal expansion>
The coefficient of thermal expansion (CTE) is based on JIS R 1618: 2002, measured at a rate of temperature increase of 5 ° C./minute using a thermal dilatometer (Bruker Ax, TD5000SA), and an average linear expansion of 50 to 350 ° C. The rate was determined. Moreover, the glass transition temperature (Tg) was calculated | required from the obtained thermal expansion curve. The results are shown in “Tg (° C.)” and “CTE (× 10 −7 / K)” in Table 1, respectively.
The density of the glass plate was measured by the Archimedes method. The results are shown in “Density (g / cm 3 )” in Table 1.
＜ガラス強化特性＞
　濃度が９８％で温度が４２５℃の溶融硝酸カリウム塩に、３時間浸漬することでガラス板の化学強化処理を行った。得られた化学強化ガラス板のＣＳ（ＭＰａ）及びＤＯＬ（μｍ）の値は折原製作所製表面応力計ＦＳＭ－６０００にて測定し、計算値として算出した。結果を表１の「ＣＳ（ＭＰａ）」及び「ＤＯＬ（μｍ）」にそれぞれ示す。また表１中「ＤＯＬ　判定」が「○」とはＤＯＬが８μｍ以上であることを表し、「×」とはＤＯＬが８μｍ未満であることを表す。  <Glass strengthening properties>
The glass plate was chemically strengthened by immersion in molten potassium nitrate having a concentration of 98% and a temperature of 425 ° C. for 3 hours. The values of CS (MPa) and DOL (μm) of the obtained chemically strengthened glass plate were measured with a surface stress meter FSM-6000 manufactured by Orihara Seisakusho and calculated as a calculated value. The results are shown in “CS (MPa)” and “DOL (μm)” in Table 1, respectively. In Table 1, “DOL determination” of “◯” indicates that the DOL is 8 μm or more, and “X” indicates that the DOL is less than 8 μm.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　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変更や修正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２０１５年８月３１日出願の日本特許出願（特願２０１５－１７０８１０）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 present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on August 31, 2015 (Japanese Patent Application No. 2015-170810), the contents of which are incorporated herein by reference.
　本発明によれば、短波長側のＵＶを照射しても、特定の波長領域における透過率を下げることなく、高強度を維持したＵＶ耐性に優れたガラス板を得ることができる。そのため、ガラス板の色味を悪くすることなく高透過かつ高強度のガラス板が得られ、ディスプレイ用途等、高透過が求められる化学強化ガラス板として非常に有用である。 According to the present invention, it is possible to obtain a glass plate excellent in UV resistance that maintains high strength without lowering the transmittance in a specific wavelength region even when UV on the short wavelength side is irradiated. Therefore, a glass plate with high transmission and high strength can be obtained without deteriorating the color of the glass plate, and it is very useful as a chemically strengthened glass plate for which high transmission is required for display applications and the like.

Claims (8)

  1. 　質量％で、ＳｉＯ２を６０～７５％、Ａｌ２Ｏ３を２～２５％、Ｎａ２Ｏを１０～２０％、Ｋ２Ｏを０～７％、ＭｇＯを０．５～１０％、ＣａＯを０～１５％及びＦｅ２Ｏ３を０．０３５～０．１２％含有し、
    　レドックス比が０．５５０未満であり、かつ
    　ＣａＯ／ＭｇＯ（質量比）が１．５以下であるＵＶ照射用ガラス板。     In mass%, SiO 2 is 60 to 75%, Al 2 O 3 is 2 to 25%, Na 2 O is 10 to 20%, K 2 O is 0 to 7%, MgO is 0.5 to 10%, CaO. 0-15% and Fe 2 O 3 0.035-0.12%,
    A glass plate for UV irradiation having a redox ratio of less than 0.550 and a CaO / MgO (mass ratio) of 1.5 or less.
  2. 　Ａｌ２Ｏ３を質量％で２～９．５％含有する請求項１に記載のＵＶ照射用ガラス板。 The glass plate for UV irradiation according to claim 1, comprising 2 to 9.5% by mass of Al 2 O 3 .
  3. 　請求項１または２に記載のＵＶ照射用ガラス板にＵＶが照射されたＵＶ照射ガラス板。 A UV irradiated glass plate obtained by irradiating UV onto the glass plate for UV irradiation according to claim 1 or 2.
  4. 　ＵＶ照射ガラス板を表面から深さ方向に１５０μｍ研磨した後のＦｅ２＋の吸収係数が、前記研磨前のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きく、次いで波長２５４ｎｍのＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さい請求項３に記載のＵＶ照射ガラス板。 The absorption coefficient of Fe 2+ after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 μm is 0.001 cm −1 or more larger than the absorption coefficient of Fe 2+ before the polishing, and then irradiated with UV having a wavelength of 254 nm. The UV-irradiated glass plate according to claim 3, wherein the absorption coefficient of Fe 2+ after that is 0.017 cm -1 or less smaller than the absorption coefficient of Fe 2+ before the irradiation.
  5. 　ＵＶ照射ガラス板を（Ｔｇ＋４０）℃の温度で１時間保持し、１℃／分の冷却速度で室温まで徐冷する処理を行った後のＦｅ２＋の吸収係数が、前記処理前のＦｅ２＋の吸収係数よりも０．００１ｃｍ－１以上大きく、次いで波長２５４ｎｍのＵＶを照射した後のＦｅ２＋の吸収係数が、前記照射前のＦｅ２＋の吸収係数よりも０．０１７ｃｍ－１以上小さい請求項３に記載のＵＶ照射ガラス板。 The absorption coefficient of Fe 2+ after holding the UV-irradiated glass plate at a temperature of (Tg + 40) ° C. for 1 hour and gradually cooling to room temperature at a cooling rate of 1 ° C./min is the Fe 2+ before the treatment. large 0.001 cm -1 or more than the absorption coefficient, then wavelength absorption coefficient of Fe 2+ after irradiation with UV at 254nm is, the irradiation claim 3 0.017 cm -1 or more smaller than the absorption coefficient of the previous Fe 2+ A UV-irradiated glass plate described in 1.
  6. 　ＵＶ照射ガラス板を表面から深さ方向に１５０μｍ研磨した後の透過率Ｔ０’と、前記研磨前の透過率Ｔ１’とが－ｌｎ（Ｔ１’／Ｔ０’）≧０．００１の関係を満たし、次いで波長２５４ｎｍのＵＶを照射した後の透過率Ｔ１と、前記照射前の透過率Ｔ０とが－ｌｎ（Ｔ１／Ｔ０）≦０．０７の関係を満たす請求項３に記載のＵＶ照射ガラス板。 The transmittance T0 ′ after polishing the UV-irradiated glass plate in the depth direction from the surface by 150 μm and the transmittance T1 ′ before polishing satisfy the relationship −ln (T1 ′ / T0 ′) ≧ 0.001. 4. The UV-irradiated glass plate according to claim 3, wherein the transmittance T1 after irradiation with UV having a wavelength of 254 nm and the transmittance T0 before irradiation satisfy a relationship of −ln (T1 / T0) ≦ 0.07.
  7. 　ＵＶ照射ガラス板を（Ｔｇ＋４０）℃の温度で１時間保持し、１℃／分の冷却速度で室温まで徐冷する処理を行った後の透過率Ｔ０’’と、前記処理前の透過率Ｔ１’’とが－ｌｎ（Ｔ１’’／Ｔ０’’）≧０．００１の関係を満たし、次いで波長２５４ｎｍのＵＶを照射した後の透過率Ｔ１と、前記照射前の透過率Ｔ０とが－ｌｎ（Ｔ１／Ｔ０）≦０．０７の関係を満たす請求項３に記載のＵＶ照射ガラス板。 The transmittance T0 '' after holding the UV-irradiated glass plate at a temperature of (Tg + 40) ° C. for 1 hour and gradually cooling to room temperature at a cooling rate of 1 ° C./min, and the transmittance T1 before the treatment ”Satisfies the relationship −ln (T1 ″ / T0 ″) ≧ 0.001, and then the transmittance T1 after irradiation with UV having a wavelength of 254 nm and the transmittance T0 before the irradiation are −ln. The UV irradiation glass plate of Claim 3 which satisfy | fills the relationship of (T1 / T0) <= 0.07.
  8. 　波長３８０～７８０ｎｍにおける平均透過率が９１％以上である請求項１または２に記載のＵＶ照射用ガラス板。 The glass plate for UV irradiation according to claim 1 or 2, wherein the average transmittance at a wavelength of 380 to 780 nm is 91% or more.
PCT/JP2016/074810 2015-08-31 2016-08-25 Glass plate having uv resistance WO2017038621A1 (en)

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WO2008099687A1 (en) * 2007-02-16 2008-08-21 Nippon Electric Glass Co., Ltd. Glass substrate for solar battery
JP2010208906A (en) * 2009-03-11 2010-09-24 Asahi Glass Co Ltd Substrate glass for optical device
WO2012057232A1 (en) * 2010-10-27 2012-05-03 旭硝子株式会社 Glass plate and process for production thereof
WO2012128180A1 (en) * 2011-03-18 2012-09-27 旭硝子株式会社 Chemically strengthened glass for display device

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JP2000290038A (en) * 1999-02-01 2000-10-17 Nippon Electric Glass Co Ltd Glass for fluorescent lamp, glass tube for fluorescent lamp and fluorescent lamp
WO2008099687A1 (en) * 2007-02-16 2008-08-21 Nippon Electric Glass Co., Ltd. Glass substrate for solar battery
JP2010208906A (en) * 2009-03-11 2010-09-24 Asahi Glass Co Ltd Substrate glass for optical device
WO2012057232A1 (en) * 2010-10-27 2012-05-03 旭硝子株式会社 Glass plate and process for production thereof
WO2012128180A1 (en) * 2011-03-18 2012-09-27 旭硝子株式会社 Chemically strengthened glass for display device

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US11407675B2 (en) 2016-07-28 2022-08-09 Corning Incorporated Glasses having resistance to photo-darkening

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