WO2020031811A1 - Method for manufacturing plate glass - Google Patents

Method for manufacturing plate glass Download PDF

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Publication number
WO2020031811A1
WO2020031811A1 PCT/JP2019/030038 JP2019030038W WO2020031811A1 WO 2020031811 A1 WO2020031811 A1 WO 2020031811A1 JP 2019030038 W JP2019030038 W JP 2019030038W WO 2020031811 A1 WO2020031811 A1 WO 2020031811A1
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WO
WIPO (PCT)
Prior art keywords
glass
glass ribbon
temperature
cooling
molten
Prior art date
Application number
PCT/JP2019/030038
Other languages
French (fr)
Japanese (ja)
Inventor
正徳 中野
一樹 内田
和孝 小野
弘輝 石橋
Original Assignee
Ａｇｃ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ａｇｃ株式会社 filed Critical Ａｇｃ株式会社
Priority to JP2020535698A priority Critical patent/JPWO2020031811A1/en
Priority to KR1020217002782A priority patent/KR20210042088A/en
Priority to CN201980051753.6A priority patent/CN112533877A/en
Publication of WO2020031811A1 publication Critical patent/WO2020031811A1/en

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/067—Forming glass sheets combined with thermal conditioning of the sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C03B18/20—Composition of the atmosphere above the float bath; Treating or purifying the atmosphere above the float bath
    • C03B18/22—Controlling or regulating the temperature of the atmosphere above the float tank

Definitions

  • the present invention relates to a method for manufacturing a sheet glass.
  • Sheet glass is mainly manufactured by a continuous forming process such as a downdraw method and a float method (for example, Patent Documents 1 and 2).
  • a typical example of the downdraw method is the fusion method.
  • a molten glass obtained by melting a glass raw material is supplied to an upper part of a forming member (hereinafter, referred to as a “forming member”).
  • the shaped member has a substantially wedge shape with a downwardly pointed cross section, and the molten glass flows down along two opposing side surfaces of the shaped member.
  • the molten glass flowing down along both side surfaces merges and integrates at the lower end (referred to as a “merging point”) of the forming member, whereby a glass ribbon is formed.
  • the glass ribbon is pulled downward while being gradually cooled by a pulling member such as a roller, and cut into predetermined dimensions.
  • a glass ribbon is formed by transporting molten glass on molten tin. Thereafter, the glass ribbon is gradually cooled and cut into predetermined dimensions.
  • JP 2016-028005 A JP-B-48-20761
  • devitrification viscosity eta L 10 5 poises (dPa ⁇ ) This is because, in the case of glass of the order of s) or lower, the viscosity of the molten glass approaches the devitrification viscosity ⁇ L during molding, and the possibility of devitrification increases.
  • devitrification refers to a phenomenon in which glass is crystallized and becomes opaque
  • the devitrification viscosity ⁇ L means a viscosity at which molten glass is devitrified.
  • the temperature of the molten glass at the devitrification viscosity ⁇ L is referred to as the devitrification temperature TL .
  • the devitrification viscosity ⁇ L is selected so as to be sufficiently higher than the viscosity of the molten glass at the start of forming.
  • the devitrification temperature T L in the conventional method of manufacturing a glass sheet is selected to be sufficiently lower than the molding start temperature i.e. the working point T W.
  • the present invention has been made in view of such a background, and in the present invention, a sheet glass is continuously formed even from a molten glass having a relatively low devitrification viscosity ⁇ L , that is, a high devitrification temperature TL. It is an object of the present invention to provide a method for manufacturing a sheet glass, which is capable of producing a sheet glass.
  • a method for producing a sheet glass Melting glass raw materials to obtain a molten glass, From the molten glass, forming a glass ribbon, Gradually cooling the glass ribbon, Has,
  • a production method is provided in which the molten glass is cooled such that an average cooling rate from a devitrification temperature TL to a softening point T S of the glass sheet becomes 1500 ° C./min or more. Is done.
  • a method for manufacturing a sheet glass capable of continuously forming a sheet glass from molten glass having a relatively low devitrification viscosity ⁇ L , that is, a high devitrification temperature TL .
  • FIG. 3 is a diagram schematically showing a relationship between each step and a glass temperature in a manufacturing method according to an embodiment of the present invention. It is the figure which showed roughly the flow of the manufacturing method of the sheet glass by one Embodiment of this invention. It is the figure which showed typically an example of the method of cooling a glass ribbon in the manufacturing method of the sheet glass by one Embodiment of this invention. It is the figure which showed typically an example of another method of cooling a glass ribbon in the manufacturing method of the flat glass by one Embodiment of this invention.
  • the conventional float method has a melting step, a forming step, and a slow cooling step.
  • a glass raw material is melted in a melting furnace to produce a molten glass.
  • the molten glass in the melting furnace is supplied onto a molten tin bath to form a glass ribbon.
  • the glass ribbon is formed into a predetermined shape while being conveyed on the molten tin.
  • the annealing step the glass ribbon is annealed in an annealing furnace.
  • FIG. 1 schematically shows a typical relationship between each of the above steps and the glass temperature in the conventional float method.
  • the horizontal axis represents three steps of melting, molding, and slow cooling
  • the vertical axis represents the approximate temperature of the glass in each step. Also, for some characteristic glass temperatures, the approximate viscosity of the glass at that temperature is also shown. Note that the horizontal axis is arranged in the order in which the three steps are performed, and thus can be considered as a time axis.
  • the glass in the melting step is dissolved, the temperature of the molten glass (the viscosity of the glass, about 10 4 about poise) working point T W is equal to or greater than.
  • the molten glass is supplied to the molding step in the work point T W. In other words, the start of molding temperature in the molding step is T W.
  • the temperature of the glass ribbon is gradually cooled from the forming start temperature T W to the annealing point T A (the viscosity of the glass is about 10 13 poise) while moving on the tin bath. Therefore, the temperature at the time of molding is completed, a T A.
  • the glass ribbon enters the slow cooling process in the annealing point T A, is gradually cooled in the slow cooling step. Thereafter, the glass ribbon is cut to produce a sheet glass.
  • the working point T W is set such that the difference ⁇ T between the working point T W and the devitrification temperature TL is sufficiently large.
  • devitrification temperature T L there is a problem that can not be higher than T W near or working point.
  • the area below the confluence corresponds to the glass ribbon forming step.
  • the conventional sheet glass manufacturing method has a problem that it is difficult to form a glass having a low devitrification viscosity ⁇ L , that is, a glass having a relatively high devitrification temperature TL by a continuous process.
  • a method for manufacturing a sheet glass Melting glass raw materials to obtain a molten glass, From the molten glass, forming a glass ribbon, Gradually cooling the glass ribbon, Has,
  • a production method is provided, wherein the molten glass is cooled such that an average cooling rate from a devitrification temperature TL to a softening point T S of the glass sheet becomes 1500 ° C./min or more. Is done.
  • FIG. 2 schematically shows an example of the relationship between each step and the glass temperature in the method for manufacturing a sheet glass according to one embodiment of the present invention.
  • the horizontal axis represents three steps of melting, molding, and slow cooling
  • the vertical axis represents the approximate temperature of the glass in each step.
  • the horizontal axis is arranged in the order in which the three processes are performed, and thus can be considered as a time axis.
  • the change in the glass temperature in the melting step and the slow cooling step is the same as in the conventional melting step and slow cooling step (see FIG. ).
  • the molten glass is at a temperature of the working point T W, is supplied to the molding process.
  • the glass ribbon is at a temperature in the vicinity annealing point T A, is conveyed to the annealing step.
  • the temperature of the glass ribbon changes from the forming start temperature (working point T W ) to the forming completion temperature (annealing point T A ).
  • the glass ribbon in the forming step has a softening point T S (viscosity of the glass is about 107.65 poise) at least from the devitrification temperature TL . in a temperature range, the average cooling rate v i is rapidly cooled so that the 1500 ° C. / min or more.
  • the temperature range from the forming start temperature (working point T W ) of the glass ribbon to the softening point T S can be quickly passed. For this reason, it is possible to significantly shorten the time during which the molten glass passes through the region of the devitrification temperature TL . This also makes it possible to significantly suppress the possibility that the glass is devitrified during the forming process.
  • crystallization can be significantly suppressed even if a glass having a relatively high devitrification temperature TL is used as a raw material.
  • a glass having a relatively high devitrification temperature T L that is, a glass having a low devitrification viscosity ⁇ L can be continuously manufactured.
  • the profile of the glass temperature shown in FIG. 2 is simplified for explanation, and in one embodiment of the present invention, the process of manufacturing the sheet glass is not exactly the same as the profile shown in FIG. It is apparent to those skilled in the art that
  • annealing step of the glass ribbon is not necessarily initiated by annealing point T A.
  • Annealing step may be started from a high temperature or a temperature lower than the annealing point T A.
  • the width of the glass ribbon is reduced (hereinafter, referred to as a “width reduction phenomenon”). May occur. This is a phenomenon that occurs when the glass ribbon shrinks in the width direction due to surface tension.
  • Such a width reduction phenomenon may reduce the accuracy of the width dimension of the glass ribbon to be formed and further, the sheet glass to be manufactured.
  • the molten glass in the step of forming the glass ribbon, has an average cooling rate from the devitrification temperature TL of the glass sheet to the softening point T S of 1500 ° C. / Minute or more.
  • the sheet glass manufacturing method according to one embodiment of the present invention can obtain an additional effect that the width reduction phenomenon of the glass ribbon can be significantly suppressed. it can.
  • the width ⁇ W of the glass ribbon can be reduced to 50 mm or less.
  • W1 is the width of the glass ribbon immediately after the start of molding, that is, immediately after the start of free fall.
  • W2 is the width of the glass ribbon immediately after completion of molding.
  • W1 is the width of the glass ribbon at the viscosity at the molding start temperature
  • W2 is the width of the glass ribbon when the viscosity is about 107.65 poise.
  • the amount of reduction ⁇ W is preferably 40 mm or less.
  • FIG. 3 schematically shows a flow of a method for manufacturing a sheet glass (hereinafter, referred to as “first manufacturing method”) according to an embodiment of the present invention.
  • the first manufacturing method includes: (1) a step of melting a glass raw material to obtain a molten glass (step S110); (2) a step of forming a glass ribbon from the molten glass (step S120); (3) a step of gradually cooling the glass ribbon (step S130); (4) a step of cutting the gradually cooled glass ribbon to form a sheet glass (step S140); Having.
  • Step S110 First, a glass raw material for a sheet glass is prepared.
  • the composition of the glass raw material is not particularly limited. However, in the first manufacturing method, a glass raw material for a sheet glass having a composition having a relatively high devitrification temperature T L , that is, a low devitrification viscosity ⁇ L can also be used significantly.
  • the glass raw material is supplied to the melting furnace to form molten glass.
  • the melting temperature is not particularly limited, but may be, for example, a temperature at which the viscosity of the glass becomes 10 0 to 10 3 poise.
  • the devitrification temperature TL of the plate glass manufactured from the glass raw material may be 800 ° C. or higher, 850 ° C. or higher, or 900 ° C. or higher.
  • the difference between the devitrification temperature T L and the working temperature T W at which the viscosity becomes 10 4 dPa ⁇ s, T L ⁇ T w, is not particularly limited, but is preferably 0 ° C. or more, and is preferably 50 ° C. It is preferably at least 100 ° C., more preferably at least 100 ° C.
  • the softening point T S of the plate glass produced from the glass raw material is not particularly limited, but may be, for example, in the range of 400 ° C. to 1100 ° C.
  • the devitrification viscosity ⁇ L of the plate glass produced from the glass raw material is, for example, in the range of 1 ⁇ 10 0 to 1 ⁇ 10 5 dPa ⁇ s (poise), and 1 ⁇ 10 1.5 to 1 ⁇ 10 4 dPa. S (poise), more preferably 1 ⁇ 10 2 to 1 ⁇ 10 3 dPa ⁇ s (poise).
  • the molten glass in the melting furnace is then transferred to the forming process.
  • Step S120 Next, a molding step is performed. In this step, the molten glass transferred from the melting furnace is formed, and a glass ribbon is formed.
  • the molten glass, the average cooling rate v i from devitrification temperature T L to the softening point T S is cooled so that the 1500 ° C. / min or more.
  • the average cooling rate v i from devitrification temperature T L to the softening point T S is, for example, 1800 ° C. / min or more and 2000 ° C. / min or more.
  • the method of performing such “quenching” of the glass ribbon is not particularly limited.
  • the glass ribbon may be rapidly cooled by spraying a cooling gas on the glass ribbon.
  • a rapid cooling method is particularly referred to as a “gas blow cooling method”.
  • the gas used in the gas blow cooling method is not particularly limited as long as it does not adversely affect the glass ribbon.
  • an inert gas such as argon and nitrogen, or air may be used as the cooling gas.
  • the temperature of the blown gas is preferably lower than the softening point T S of the molten glass.
  • the temperature of the blown gas be lower by 1 ° C. to 100 ° C. than the softening point T S of the molten glass.
  • FIG. 4 schematically shows an example of a configuration of an apparatus used for cooling a glass ribbon by a gas blow cooling method.
  • the device 100 has a housing member 110 and a gas supply member 125.
  • the housing member 110 has an upper member 112 and a bottom member 115.
  • the upper member 112 has an upper surface 112a and four side surfaces 112b surrounding the upper surface 112a.
  • a concave portion 114 whose upper side is opened is formed in the upper surface 112a.
  • the two opposing side surfaces 112b extend parallel to each other in a vertical direction (a downward direction on the paper) and in a direction perpendicular to the paper.
  • the bottom member 115 of the housing member 110 has a substantially inverted triangular cross section, and has two slopes 116a and 116b and an apex 116c connecting both slopes.
  • the first inclined surface 116a, the second inclined surface 116b, and the apex 116c also extend in a direction perpendicular to the paper surface, and therefore, the lower portion of the housing member 110 has a substantially triangular prism shape.
  • the upper part of the first slope 116a is connected to one side surface 112b of the upper member 112, and the upper part of the second slope 116b is connected to one side surface 112b of the upper member 112.
  • the gas supply member 125 has one or more nozzles.
  • the gas supply member 125 includes a first set of nozzles 127a and 127b arranged at symmetric positions and a second set of nozzles 129a and 129b arranged at symmetric positions.
  • the first set of nozzles 127a and 127b and the second set of nozzles 129a and 129b are installed at mutually different heights.
  • the gas supply member 125 has a total of four nozzles 127a, 127b, 129a, and 129b.
  • the molten glass 150 is supplied to the concave portion 114 of the upper member 112 of the housing member 110.
  • the recess 114 accommodates the molten glass 150. However, when the molten glass 150 that exceeds the storage volume of the recess 114 is supplied, the molten glass 150 overflows along the opposite side surface 112b of the storage member 110, and the first molten glass portion 152a and the second molten glass 150 It becomes the part 152b.
  • the first molten glass portion 152a flows further downward along the first slope 116a of the housing member 110.
  • the second molten glass portion 152b flows further downward along the second slope 116b of the housing member 110.
  • the first molten glass portion 152a and the second molten glass portion 152b reach the vertex 116c and are integrated there.
  • the combined molten glass becomes a glass ribbon 170 and further extends in the vertical direction. That is, the vertex 116c is the molding start position, and the molding of the glass ribbon 170 is started from here.
  • the apparatus 100 has the gas supply member 125 at a position close to the glass ribbon 170, particularly at a position where the forming is started (the vertex 116 c).
  • a cooling gas is blown toward the glass ribbon 170 from each of the nozzles 127a, 127b, 129a, and 129b of the gas supply member 125.
  • the apparatus 100 can rapidly cool the glass ribbon 170 immediately after the start of forming the molten glass 150.
  • the configuration example of the apparatus 100 shown in FIG. 4 is merely an example, and the gas blow cooling method may be performed using another apparatus.
  • the glass ribbon may be rapidly cooled by continuously bringing the glass ribbon into contact with the cooled roll.
  • a rapid cooling method is referred to as a “roll cooling method”.
  • the roll cooling method for example, it is preferable to use a roll maintained at a sufficiently low temperature.
  • the temperature of the roll is lower than the softening point T S of the molten glass.
  • the temperature of the roll is 1 ° C. to 100 ° C. lower than the softening point T S of the molten glass.
  • Examples of the method for cooling the roll include water cooling, air cooling, and oil cooling in which low-temperature water, gas, and oil are circulated for cooling.
  • FIG. 5 schematically shows an example of a configuration of an apparatus used for cooling a glass ribbon by a roll cooling method.
  • the apparatus 300 for performing the roll cooling method includes the housing member 310 and at least one pair of cooling rolls 360.
  • the apparatus 300 further includes a transport roller and an annealing furnace downstream of the cooling roll 360.
  • the transport roller has a role of drawing out the glass ribbon 370 sent from the cooling roll 360 and introducing the glass ribbon 370 into the lehr.
  • the storage member 310 has a role of storing the molten glass 350 supplied from a melting furnace (not shown) and overflowing the molten glass 350 that could not be stored downward.
  • the housing member 310 may have a form like the housing member 110 shown in FIG. 4 described above.
  • the molten glass 350 is supplied to the upper part of the housing member 310.
  • the glass ribbon 370 flows further downward and is supported by being sandwiched between the two cooling rolls 360.
  • the cooling roll 360 is maintained at a predetermined temperature by water, gas, oil, or the like, and the glass ribbon 370 in contact with the cooling roll 360 is rapidly cooled here.
  • a transport roller (not shown) is provided downstream of the cooling roll 360. With this transport roller, the glass ribbon 370 is pulled out to the downstream side of the cooling roll 360 and introduced into the lehr.
  • the glass ribbon 370 introduced into the annealing furnace is gradually cooled, and when it reaches a predetermined temperature, is cut into a predetermined size to produce a sheet glass.
  • the glass ribbon 370 can be rapidly cooled using the cooling roll 360.
  • a method of spraying a liquid onto molten glass there is a method of spraying a liquid onto molten glass.
  • a glass ribbon can be rapidly cooled by using a relatively vaporizable liquid as a spray liquid at a forming temperature of the molten glass (working point T W ) or a temperature region in the vicinity thereof.
  • a rapid cooling method is particularly referred to as a “liquid spray cooling method”.
  • Liquids that can be used in the liquid spray cooling method include, for example, water, ethanol, acetone, and the like. These liquids are less likely to adversely affect the glass ribbon, even when in contact with the glass ribbon.
  • the temperature of the liquid to be sprayed is preferably lower than the softening point T S of the molten glass.
  • the glass ribbon may be rapidly cooled by continuously dropping the glass ribbon onto a molten metal bath.
  • the molten metal serving as a cooling source includes, but is not limited to, tin, lead, zinc, mercury, copper, and the like.
  • the molten metal may be a single metal or an alloy of two or more selected from the above-described metal group.
  • the temperature of the molten metal is preferably lower than the softening point T S of the molten glass.
  • the temperature of the molten metal is 1 ° C. to 100 ° C. lower than the softening point T S of the molten glass.
  • the molten glass is quenched and the glass ribbon is formed by the above method.
  • Such rapid cooling of the glass ribbon in the forming step significantly reduces the time for the molten glass to pass through the devitrification temperature TL . Further, as a result, even when a sheet glass is manufactured from glass having a relatively high devitrification temperature T L , that is, a glass having a low devitrification viscosity ⁇ L , there is a possibility that a devitrification phenomenon occurs in the glass ribbon in the forming process. It can be suppressed significantly.
  • Step S130 Next, the formed glass ribbon is gradually cooled. Usually, this step is performed in a lehr.
  • the temperature of the glass ribbon to be supplied to the annealing furnace is a front and rear annealing point T A. This is about 10 13 poise in terms of the viscosity of glass.
  • the annealing point T A is, for example, in the range of 450 ° C. to 700 ° C.
  • Step S140 Thereafter, the glass ribbon is cut to predetermined dimensions.
  • the refractive index of the manufactured glass sheet may be, for example, in the range of 1.40 to 2.20.
  • a high refractive index when required, it is preferably 1.60 or more, more preferably 1.65 or more, still more preferably 1.70 or more, and particularly preferably 1.75 or more.
  • Such a high-refractive-index plate glass can be applied to, for example, a video display device such as a high-performance liquid crystal panel, a light extraction member of a light emitting device, and the like.
  • low dispersion or anomalous dispersion, filter applications to cut a specific wavelength for example, when it is necessary to cut light in the near infrared region, 1.50 or less, preferably 1.48 or less, 1.45 or less is more preferable.
  • a low-refractive-index glass can be used for correcting visibility in an image pickup device and correcting chromatic aberration of an image pickup optical system.
  • the manufactured sheet glass may have a Young's modulus in a range of, for example, 90 GPa to 150 GPa.
  • the Young's modulus is preferably 95 GPa or more, more preferably 100 GPa or more, further preferably 105 GPa or more, and particularly preferably 110 GPa or more.
  • Such a glass can be applied to, for example, a substrate of a magnetic disk for information recording, a substrate for a display, a support glass for semiconductor packaging, a carrier glass for a fan-out process, a cover glass for a mobile information device, and the like. it can.
  • Example 1 A production test of a sheet glass was performed by the following method.
  • FIG. 4 schematically shows a part of a plate glass manufacturing apparatus used for the test.
  • the device 100 includes a housing member 110 and a gas supply member 125. Although not shown in FIG. 4, the apparatus 100 further includes a slow cooling unit downstream of the gas supply member 125.
  • the storage member 110 has a role of storing the molten glass supplied from the melting furnace (not shown) and overflowing the molten glass that cannot be stored downward.
  • the molten glass 150 is supplied to the upper part of the housing member 110.
  • the molten glass 150 is supplied to the concave portion 114 of the upper member 112 of the housing member 110.
  • the recess 114 accommodates the molten glass 150. However, the molten glass 150 that exceeds the storage volume of the concave portion 114 is supplied, and the molten glass 150 overflows along the opposite side surface 112b of the storage member 110, and the first molten glass portion 152a and the second molten glass portion 152b.
  • the first molten glass portion 152a flows further downward along the first slope 116a of the housing member 110.
  • the second molten glass portion 152b flows further downward along the second slope 116b of the housing member 110.
  • the first molten glass portion 152a and the second molten glass portion 152b reach the vertex 116c and are integrated there.
  • the combined molten glass becomes a glass ribbon 170 and further extends in the vertical direction. That is, the vertex 116c is the molding start position, and the molding of the glass ribbon 170 is started from here.
  • a cooling gas is blown toward the glass ribbon 170 from each of the nozzles 127a, 127b, 129a, and 129b of the gas supply member 125 installed at a position close to the molding start position (apex 116c). Quench quickly.
  • the positions and shapes of the nozzles 127a, 127b, 129a, and 129b are adjusted such that the cooling gas is blown over the glass ribbon 170 over a region of 100 mm in the vertical direction.
  • the rapidly cooled glass ribbon 170 is introduced into the slow cooling unit.
  • the glass ribbon 170 introduced into the slow cooling section is gradually cooled, and when it reaches a predetermined temperature, is cut into a predetermined size to produce a sheet glass.
  • the temperature of the molten glass 150 supplied to the housing member 110 was about 1100 ° C.
  • the temperature of the molten glass 150 (glass ribbon 170) at the vertex 116c (hereinafter, referred to as “T 1 (° C.)”) was 1,060 ° C.
  • the transport speed of the glass ribbon 170 at this time was 300 mm / min. At this time, the thickness of the glass ribbon 170 was about 3.0 mm.
  • the temperature of the glass ribbon 170 immediately after passing between the nozzles of the gas supply member 125 was 660 ° C.
  • the time when the glass ribbon 170 is at the vertex 116c is set to a zero point (t 1 ), and the temperature immediately after the glass ribbon 170 passes between the nozzles of the gas supply member (hereinafter, “T 2 (° C.)”) ), That is, the time required to reach 660 ° C. (referred to as “t 2 (minute)”).
  • the second average cooling rate v ii was 2100 ° C./min.
  • the width ⁇ W of the glass ribbon 170 determined as described above was measured, the width ⁇ W was 25 mm.
  • Example 2 A production test of a sheet glass was carried out in the same manner as in Example 1.
  • Example 2 the transport speed of the glass ribbon 170 was 400 mm / min. At that time, the thickness of the glass ribbon 170 was about 2.2 mm. Other conditions are the same as in the case of Example 1.
  • the second average cooling rate v ii obtained from the above equation (1) was 2350 ° C./min.
  • the amount of width ⁇ W of the glass ribbon 170 was 27 mm.
  • Example 3 A production test of a sheet glass was carried out in the same manner as in Example 1.
  • Example 3 the transfer speed of the glass ribbon 170 was set to 600 mm / min. At that time, the thickness of the glass ribbon 170 was about 1.5 mm. Other conditions are the same as in the case of Example 1.
  • the second average cooling rate v ii obtained from the above equation (1) was 2850 ° C./min.
  • the width reduction ⁇ W of the glass ribbon 170 was 32 mm.
  • Example 4 A production test of a sheet glass was performed by the following method.
  • the temperature of the molten glass 350 supplied to the housing member 310 was about 1100 ° C.
  • the temperature of the molten glass 350 (glass ribbon 370) at the junction 320 (hereinafter, referred to as “T 1 (° C.)”) was 1,060 ° C.
  • the surface temperature of the two cooling rolls 360 was maintained at 660 ° C., and the transport speed of the glass ribbon 370 on the surface of the cooling rolls 360 was 300 mm / min.
  • the thickness of the glass ribbon 370 conveyed between the two cooling rolls 360 was about 3.0 mm.
  • the time when the glass ribbon 370 is at the junction 320 is set to a zero point (t 1 ), and the temperature of the glass ribbon 370 is the temperature of the cooling roll 360 (hereinafter, referred to as “T 2 (° C.)”); That is, the time required to reach 660 ° C. (referred to as “t 2 (minute)”) was measured.
  • the glass ribbon 370 is in a position in direct contact with the cooling roll 360, immediately after contact with the cooling roll 360, is quenched to a temperature T 2 of the said cooling roll 360.
  • the time until the surface temperature of the glass ribbon 370 becomes substantially equal to the temperature T 2 of the cooling roll 360 is defined as t 2 (minutes).
  • the second average cooling rate v ii was 2350 ° C./min.
  • the amount of width ⁇ W of the glass ribbon 370 was 20 mm.
  • Example 5 A production test of a sheet glass was performed in the same manner as in Example 4.
  • Example 5 the transport speed of the glass ribbon 370 was 400 mm / min. At that time, the thickness of the glass ribbon 370 was about 2.2 mm.
  • the other conditions are the same as in Example 4.
  • the second average cooling rate v ii obtained from the above equation (1) was 3200 ° C./min.
  • the amount of width ⁇ W of the glass ribbon 370 was 24 mm.
  • Example 6 A production test of a sheet glass was performed in the same manner as in Example 4.
  • Example 6 the transport speed of the glass ribbon 370 was set to 600 mm / min. At that time, the thickness of the glass ribbon 370 was about 1.5 mm.
  • the other conditions are the same as in Example 4.
  • the second average cooling rate v ii obtained from the above equation (1) was 4000 ° C./min.
  • the width reduction ⁇ W of the glass ribbon 370 was 29 mm.
  • Example 7 A sheet glass production test was performed in the same manner as in Example 1 except that the glass ribbon was cooled using a molten tin bath instead of the gas supply member. The temperature of the molten tin was maintained at 660 ° C., and the transport speed of the glass ribbon on the surface of the molten tin bath was 410 mm / min. The thickness of the glass ribbon was about 2.2 mm.
  • the second average cooling rate v ii obtained from the above equation (1) was 1800 ° C./min.
  • the amount of width ⁇ W of the glass ribbon was 25 mm.
  • Example 8 A production test of a sheet glass was carried out in the same manner as in Example 1.
  • Example 8 the shape and position of each nozzle and the supply amount of the cooling gas discharged from each nozzle were adjusted so that the cooling gas was blown over the region of the glass ribbon 170 in the vertical direction of 20 mm.
  • the supply amount of the cooling gas per unit area is the same as in Example 1.
  • the transfer speed of the glass ribbon 170 was 600 mm / min. At that time, the thickness of the glass ribbon 170 was about 2.3 mm.
  • Other conditions are the same as in the case of Example 1.
  • the second average cooling rate v ii obtained from the above equation (1) was 420 ° C./min.
  • the width ⁇ W of reduction of the glass ribbon was 85 mm.
  • the average cooling rate v i from devitrification temperature T L of the glass ribbon to the softening point T S can to 1500 ° C. / min or more was confirmed. Further, even when the working point T W (or molding start temperature T 1) and the devitrification temperature T L is closer, by an average cooling rate v i of the glass ribbon between 1500 ° C. / min or more, It was confirmed that the crystallization of the molten glass was suppressed.

Abstract

Provided is a method for manufacturing plate glass, the method having: a step for melting a glass material to obtain a molten glass; a step for molding a glass ribbon from the molten glass; and a step for gradually cooling the glass ribbon, wherein, in the step for molding the glass ribbon, the molten glass is cooled such that the average cooling speed from the devitrification temperature TL of the plate glass to the softening point TS is 1,500 °C/minute or more.

Description

板ガラスの製造方法Manufacturing method of sheet glass
　本発明は、板ガラスの製造方法に関する。 The present invention relates to a method for manufacturing a sheet glass.
　板ガラスは、主に、ダウンドロー法およびフロート法などの連続成形プロセスにより製造されている（例えば特許文献１、２）。 Sheet glass is mainly manufactured by a continuous forming process such as a downdraw method and a float method (for example, Patent Documents 1 and 2).
　ダウンドロー法の代表例は、フュージョン法である。 代表 A typical example of the downdraw method is the fusion method.
　この方法では、まずガラス原料を溶解することにより得られた溶融ガラスが、成形用の部材（以下、「成形部材」と称する）の上部に供給される。成形部材は、断面が下向きに尖った略くさび状となっており、溶融ガラスは、この成形部材の対向する２つの側面に沿って流下される。両側面に沿って流下する溶融ガラスは、成形部材の下端（「合流点」という）で合流、一体化され、これによりガラスリボンが成形される。その後、このガラスリボンは、ローラなどの牽引部材により、徐冷されながら下向きに牽引され、所定の寸法で切断される。 In this method, first, a molten glass obtained by melting a glass raw material is supplied to an upper part of a forming member (hereinafter, referred to as a “forming member”). The shaped member has a substantially wedge shape with a downwardly pointed cross section, and the molten glass flows down along two opposing side surfaces of the shaped member. The molten glass flowing down along both side surfaces merges and integrates at the lower end (referred to as a “merging point”) of the forming member, whereby a glass ribbon is formed. Thereafter, the glass ribbon is pulled downward while being gradually cooled by a pulling member such as a roller, and cut into predetermined dimensions.
　一方、フロート法では、溶融ガラスを溶融スズ上で搬送させることにより、ガラスリボンが成形される。その後、ガラスリボンは、徐冷され、所定の寸法で切断される。 On the other hand, in the float method, a glass ribbon is formed by transporting molten glass on molten tin. Thereafter, the glass ribbon is gradually cooled and cut into predetermined dimensions.
特開２０１６－０２８００５号公報JP 2016-028005 A 特公昭４８－２０７６１号公報JP-B-48-20761
　従来の板ガラスの製造方法では、ダウンドロー法およびフロート法のいずれにおいても、比較的失透粘性（以下、「ηＬ」で表す）の低いガラスを連続的に成形することは難しいという問題がある。これは、溶融ガラスの成形開始時の粘度は通常１０４ポアズ（ｄＰａ・ｓ）程度の領域であるが、失透粘性ηＬが低いガラス、すなわち失透粘性ηＬが１０５ポアズ（ｄＰａ・ｓ）程度又はそれより低いガラスの場合、成形の際に溶融ガラスの粘度が失透粘性ηＬに接近し失透が生じる可能性が高くなるためである。 In the conventional sheet glass manufacturing method, there is a problem that it is difficult to continuously form glass having relatively low devitrification viscosity (hereinafter, referred to as “η L ”) in both the downdraw method and the float method. . This is the viscosity at the time of start of molding of the molten glass is an area of usually about 10 4 poise (dPa · s), the glass devitrification viscosity eta L is low, i.e. devitrification viscosity eta L 10 5 poises (dPa · This is because, in the case of glass of the order of s) or lower, the viscosity of the molten glass approaches the devitrification viscosity η L during molding, and the possibility of devitrification increases.
　ここで、「失透」とは、ガラスに結晶化が起こって不透明になる現象を表し、失透粘性ηＬは、溶融ガラスに失透が生じる粘度を意味する。また、失透粘性ηＬにおける溶融ガラスの温度を、失透温度ＴＬという。 Here, “devitrification” refers to a phenomenon in which glass is crystallized and becomes opaque, and the devitrification viscosity η L means a viscosity at which molten glass is devitrified. Further, the temperature of the molten glass at the devitrification viscosity η L is referred to as the devitrification temperature TL .
　このため、従来の板ガラスの連続製造方法では、失透粘性ηＬは、溶融ガラスの成形開始時の粘度より十分高くなるように選定されている。言い換えると、溶融ガラスが成形開始温度（作業点ＴＷとも称する）に接近すると成形の際に溶融ガラスに失透が生じる可能性が高くなるため、従来の板ガラスの製造方法では失透温度ＴＬは成形開始温度すなわち作業点ＴＷよりも十分低くなるように選定されている。 For this reason, in the conventional continuous manufacturing method of a sheet glass, the devitrification viscosity η L is selected so as to be sufficiently higher than the viscosity of the molten glass at the start of forming. In other words, since the possibility that devitrification molten glass occurs during molding the molten glass approaches the shaping starting temperature (also referred to as working point T W) becomes high, the devitrification temperature T L in the conventional method of manufacturing a glass sheet is selected to be sufficiently lower than the molding start temperature i.e. the working point T W.
　しかしながら、上記のようなガラスリボンの成形時に粘度や温度に関する制約を排除または緩和することができれば、より多くの組成のガラス板を連続で製造することが可能となり、よりいっそうユーザの要望に合致するガラス板を提供することができると考えられる。 However, if the restrictions on the viscosity and temperature can be eliminated or relaxed during the molding of the glass ribbon as described above, it becomes possible to continuously produce a glass sheet having a greater composition, which further meets the needs of the user. It is believed that a glass plate can be provided.
　本発明は、このような背景に鑑みなされたものであり、本発明では、比較的低い失透粘性ηＬ、すなわち高い失透温度ＴＬを有する溶融ガラスからも、連続的に板ガラスを成形することが可能な、板ガラスの製造方法を提供することを目的とする。 The present invention has been made in view of such a background, and in the present invention, a sheet glass is continuously formed even from a molten glass having a relatively low devitrification viscosity η L , that is, a high devitrification temperature TL. It is an object of the present invention to provide a method for manufacturing a sheet glass, which is capable of producing a sheet glass.
　本発明では、板ガラスの製造方法であって、
　ガラス原料を溶解して、溶融ガラスを得る工程と、
　前記溶融ガラスから、ガラスリボンを成形する工程と、
　前記ガラスリボンを徐冷する工程と、
　を有し、
　前記ガラスリボンを成形する工程では、前記溶融ガラスは、前記板ガラスの失透温度ＴＬから軟化点ＴＳまでの平均冷却速度が１５００℃／分以上となるように冷却される、製造方法が提供される。 In the present invention, a method for producing a sheet glass,
Melting glass raw materials to obtain a molten glass,
From the molten glass, forming a glass ribbon,
Gradually cooling the glass ribbon,
Has,
In the step of forming the glass ribbon, a production method is provided in which the molten glass is cooled such that an average cooling rate from a devitrification temperature TL to a softening point T S of the glass sheet becomes 1500 ° C./min or more. Is done.
　本発明では、比較的低い失透粘性ηＬ、すなわち高い失透温度ＴＬを有する溶融ガラスからも、連続的に板ガラスを成形することが可能な、板ガラスの製造方法を提供することができる。 According to the present invention, it is possible to provide a method for manufacturing a sheet glass capable of continuously forming a sheet glass from molten glass having a relatively low devitrification viscosity η L , that is, a high devitrification temperature TL .
従来のフロート法における各工程とガラス温度の関係を模式的に示した図である。It is the figure which showed typically the relationship between each process and glass temperature in the conventional float method. 本発明の一実施形態による製造方法における各工程とガラス温度の関係を模式的に示した図である。FIG. 3 is a diagram schematically showing a relationship between each step and a glass temperature in a manufacturing method according to an embodiment of the present invention. 本発明の一実施形態による板ガラスの製造方法のフローを概略的に示した図である。It is the figure which showed roughly the flow of the manufacturing method of the sheet glass by one Embodiment of this invention. 本発明の一実施形態による板ガラスの製造方法において、ガラスリボンを冷却する方法の一例を、模式的に示した図である。It is the figure which showed typically an example of the method of cooling a glass ribbon in the manufacturing method of the sheet glass by one Embodiment of this invention. 本発明の一実施形態による板ガラスの製造方法において、ガラスリボンを冷却する別の方法の一例を、模式的に示した図である。It is the figure which showed typically an example of another method of cooling a glass ribbon in the manufacturing method of the flat glass by one Embodiment of this invention.
　以下、本発明の一実施形態について説明する。 Hereinafter, an embodiment of the present invention will be described.
　まず、本発明についてより良く理解するため、従来の板ガラスの製造方法について簡単に説明する。なお、ここでは、従来の板ガラスの製造方法としてフロート法を採用し、その工程について説明する。 First, in order to better understand the present invention, a conventional method for manufacturing a sheet glass will be briefly described. Here, a float method is adopted as a conventional sheet glass manufacturing method, and its steps will be described.
　従来のフロート法は、溶解工程、成形工程、および徐冷工程を有する。まず、溶解工程では、ガラス原料が溶解炉内で溶解され、溶融ガラスが製造される。次に、成形工程では、溶解炉の溶融ガラスが溶融スズ浴上に供給され、ガラスリボンとなる。このガラスリボンは、溶融スズ上を搬送されながら、所定の形状に成形される。さらに、徐冷工程では、ガラスリボンが徐冷炉で徐冷される。 The conventional float method has a melting step, a forming step, and a slow cooling step. First, in a melting step, a glass raw material is melted in a melting furnace to produce a molten glass. Next, in the forming step, the molten glass in the melting furnace is supplied onto a molten tin bath to form a glass ribbon. The glass ribbon is formed into a predetermined shape while being conveyed on the molten tin. Further, in the annealing step, the glass ribbon is annealed in an annealing furnace.
　図１には、従来のフロート法における、上記各工程とガラス温度の典型的な関係を、模式的に示す。 FIG. 1 schematically shows a typical relationship between each of the above steps and the glass temperature in the conventional float method.
　図１において、横軸は、溶解、成形、および徐冷の３工程を表しており、縦軸は、各工程におけるガラスの概略的な温度を表している。また、一部の特徴的なガラス温度に関しては、その温度におけるガラスの大凡の粘度も示されている。なお、横軸は、３工程が実施される順番に並んでおり、従って時間軸と考えることもできる。 In FIG. 1, the horizontal axis represents three steps of melting, molding, and slow cooling, and the vertical axis represents the approximate temperature of the glass in each step. Also, for some characteristic glass temperatures, the approximate viscosity of the glass at that temperature is also shown. Note that the horizontal axis is arranged in the order in which the three steps are performed, and thus can be considered as a time axis.
　図１のプロファイル１０に示すように、溶解工程ではガラスは溶解されており、溶融ガラスの温度は、作業点ＴＷ（ガラスの粘度は、約１０４ポアズ程度）以上となっている。この溶融ガラスは、作業点ＴＷで成形工程に供給される。換言すれば、成形工程における成形開始温度は、ＴＷである。 As shown in the profile 10 of FIG. 1, the glass in the melting step is dissolved, the temperature of the molten glass (the viscosity of the glass, about 10 4 about poise) working point T W is equal to or greater than. The molten glass is supplied to the molding step in the work point T W. In other words, the start of molding temperature in the molding step is T W.
　成形工程では、ガラスリボンの温度は、スズ浴上を移動中に、成形開始温度ＴＷから徐冷点ＴＡ（ガラスの粘度は、約１０１３ポアズ程度）まで徐々に冷却される。従って、成形完了時の温度は、ＴＡである。 In the forming step, the temperature of the glass ribbon is gradually cooled from the forming start temperature T W to the annealing point T A (the viscosity of the glass is about 10 13 poise) while moving on the tin bath. Therefore, the temperature at the time of molding is completed, a T A.
　次に、ガラスリボンは、徐冷点ＴＡで徐冷工程に入り、この徐冷工程において徐冷される。その後、ガラスリボンが切断され、板ガラスが製造される。 Then, the glass ribbon enters the slow cooling process in the annealing point T A, is gradually cooled in the slow cooling step. Thereafter, the glass ribbon is cut to produce a sheet glass.
　ここで、前述のように、従来のフロート法では、作業点ＴＷと失透温度ＴＬとが接近しすぎると、ガラスが失透する可能性が高くなる。例えば、失透粘性ηＬの低い板ガラスを製造する場合、溶解工程や成形工程等の溶融ガラスの流れが停滞し易い箇所などでは、溶融ガラスの温度が失透温度ＴＬ近傍に留まる時間が長くなるため、比較的容易にガラスに失透現象が生じ得る。 Here, as described above, in the conventional float process, when the working point T W and devitrification temperature T L is too close, more likely to glass is devitrified. For example, when manufacturing a sheet glass having a low devitrification viscosity η L, in a place where the flow of the molten glass tends to stagnate in a melting step, a forming step, or the like, the time during which the temperature of the molten glass stays near the devitrification temperature TL is long. Therefore, the devitrification phenomenon can occur in the glass relatively easily.
　そこで、このような失透現象を回避するため、作業点ＴＷは、該作業点ＴＷと失透温度ＴＬの差ΔＴが十分に大きくなるように設定されている。逆に言えば、このような失透現象に関する制約のため、失透温度ＴＬは、作業点ＴＷ近傍またはそれより高くすることはできないという問題がある。 Therefore, in order to avoid such a devitrification phenomenon, the working point T W is set such that the difference ΔT between the working point T W and the devitrification temperature TL is sufficiently large. Conversely, due to the limitations regarding such devitrification, devitrification temperature T L, there is a problem that can not be higher than T W near or working point.
　このような問題は、従来のフュージョン法においても同様に生じる。フュージョン法においても、ガラス原料の溶解工程（作業点ＴＷ以上の温度域）、ガラスリボンの成形工程（作業点ＴＷ～徐冷点ＴＡの温度域）、およびガラスリボンの徐冷工程（徐冷点ＴＡ以下の温度域）が存在し、作業点ＴＷは、該作業点ＴＷと失透温度ＴＬの差ΔＴが十分に大きくなるように設定される必要があるためである。 Such a problem similarly occurs in the conventional fusion method. Also in the fusion process, (the temperature range of not lower than the working point T W) the step of melting glass materials, (the temperature range of the working point T W ~ annealing point T A) forming process of the glass ribbon, and the glass ribbon slow cooling step ( annealing point T a below temperature range) is present, working point T W is the it is necessary to difference ΔT of the working point T W and devitrification temperature T L is set to be sufficiently large .
　なお、フュージョン法の場合は、前述の合流点以下の領域がガラスリボンの成形工程に対応する。 In the case of the fusion method, the area below the confluence corresponds to the glass ribbon forming step.
　このように、従来の板ガラスの製造方法では、低い失透粘性ηＬ、すなわち比較的失透温度ＴＬの高いガラスを連続プロセスで成形することは難しいという問題がある。 As described above, the conventional sheet glass manufacturing method has a problem that it is difficult to form a glass having a low devitrification viscosity η L , that is, a glass having a relatively high devitrification temperature TL by a continuous process.
　これに対して、本発明の一実施形態では、
　板ガラスの製造方法であって、
　ガラス原料を溶解して、溶融ガラスを得る工程と、
　前記溶融ガラスから、ガラスリボンを成形する工程と、
　前記ガラスリボンを徐冷する工程と、
　を有し、
　前記ガラスリボンを成形する工程では、前記溶融ガラスは、前記板ガラスの失透温度ＴＬから軟化点ＴＳまでの平均冷却速度が１５００℃／分以上となるように冷却される、製造方法が提供される。 In contrast, in one embodiment of the present invention,
A method for manufacturing a sheet glass,
Melting glass raw materials to obtain a molten glass,
From the molten glass, forming a glass ribbon,
Gradually cooling the glass ribbon,
Has,
In the step of forming the glass ribbon, a production method is provided, wherein the molten glass is cooled such that an average cooling rate from a devitrification temperature TL to a softening point T S of the glass sheet becomes 1500 ° C./min or more. Is done.
　図２には、本発明の一実施形態による板ガラスの製造方法における、各工程とガラス温度の関係の一例を、模式的に示す。図２において、横軸は、溶解、成形、および徐冷の３工程を表しており、縦軸は、各工程におけるガラスの概略的な温度を表している。また、横軸は、３工程が実施される順番に並んでおり、従って時間軸と考えることもできる。 FIG. 2 schematically shows an example of the relationship between each step and the glass temperature in the method for manufacturing a sheet glass according to one embodiment of the present invention. In FIG. 2, the horizontal axis represents three steps of melting, molding, and slow cooling, and the vertical axis represents the approximate temperature of the glass in each step. The horizontal axis is arranged in the order in which the three processes are performed, and thus can be considered as a time axis.
　図２のプロファイル１１に示すように、本発明の一実施形態による板ガラスの製造方法において、溶解工程および徐冷工程におけるガラス温度の変化は、従来の溶解工程および徐冷工程の場合（図１参照）とほぼ同様である。 As shown in the profile 11 of FIG. 2, in the method of manufacturing a flat glass according to one embodiment of the present invention, the change in the glass temperature in the melting step and the slow cooling step is the same as in the conventional melting step and slow cooling step (see FIG. ).
　すなわち、溶融ガラスは、作業点ＴＷの温度で、成形工程に供給される。また、ガラスリボンは、徐冷点ＴＡ近傍の温度で、徐冷工程に搬送される。また、成形工程では、ガラスリボンの温度は、成形開始温度（作業点ＴＷ）から成形完了温度（徐冷点ＴＡ）まで変化する。 That is, the molten glass is at a temperature of the working point T W, is supplied to the molding process. The glass ribbon is at a temperature in the vicinity annealing point T A, is conveyed to the annealing step. In the forming step, the temperature of the glass ribbon changes from the forming start temperature (working point T W ) to the forming completion temperature (annealing point T A ).
　ただし、プロファイル１１に示すように、本発明の一実施形態では、成形工程におけるガラスリボンは、少なくとも失透温度ＴＬから軟化点ＴＳ（ガラスの粘度は、約１０７．６５ポアズ程度）の温度領域において、平均冷却速度ｖｉが１５００℃／分以上となるように急冷される。 However, as shown in the profile 11, in one embodiment of the present invention, the glass ribbon in the forming step has a softening point T S (viscosity of the glass is about 107.65 poise) at least from the devitrification temperature TL . in a temperature range, the average cooling rate v i is rapidly cooled so that the 1500 ° C. / min or more.
　このようなプロファイル１１では、成形工程において、ガラスリボンの成形開始温度（作業点ＴＷ）から、軟化点ＴＳまでの温度領域を、迅速に経過させることができる。このため、溶融ガラスが失透温度ＴＬの領域を通過する時間を有意に短くすることが可能となる。また、これにより、ガラスが成形過程で失透する可能性を、有意に抑制することが可能となる。 With such a profile 11, in the forming step, the temperature range from the forming start temperature (working point T W ) of the glass ribbon to the softening point T S can be quickly passed. For this reason, it is possible to significantly shorten the time during which the molten glass passes through the region of the devitrification temperature TL . This also makes it possible to significantly suppress the possibility that the glass is devitrified during the forming process.
　従って、本発明の一実施形態では、仮に失透温度ＴＬが比較的高いガラスを原料として使用しても、結晶化を有意に抑制することができる。また、これにより、本発明の一実施形態では、比較的高い失透温度ＴＬ、すなわち低い失透粘性ηＬを有するガラスも、連続的に製造することができる。 Therefore, in one embodiment of the present invention, crystallization can be significantly suppressed even if a glass having a relatively high devitrification temperature TL is used as a raw material. In addition, thereby, in one embodiment of the present invention, a glass having a relatively high devitrification temperature T L , that is, a glass having a low devitrification viscosity η L can be continuously manufactured.
　なお、図２に示したガラス温度のプロファイルは、説明用のため簡略化されたものであり、実際に本発明の一実施形態において、板ガラスを製造する過程が図２に示したプロファイルとは正確に対応しないことは、当業者には明らかである。 In addition, the profile of the glass temperature shown in FIG. 2 is simplified for explanation, and in one embodiment of the present invention, the process of manufacturing the sheet glass is not exactly the same as the profile shown in FIG. It is apparent to those skilled in the art that
　例えば、ガラスリボンの徐冷工程は、必ずしも徐冷点ＴＡで開始される必要はない。徐冷工程は、徐冷点ＴＡよりも高い温度または低い温度から開始されても良い。 For example, annealing step of the glass ribbon is not necessarily initiated by annealing point T A. Annealing step may be started from a high temperature or a temperature lower than the annealing point T A.
　ところで、従来のフュージョン法では、溶融ガラスが成形部材の前記合流点を超えて落下し、ガラスリボンの成形が開始されると、ガラスリボンの幅が縮小する現象（以下「縮幅現象」という）が生じる場合がある。これは、表面張力によって、ガラスリボンが幅方向に収縮することによって生じる現象である。 By the way, in the conventional fusion method, when the molten glass falls beyond the confluence of the forming member and the forming of the glass ribbon is started, the width of the glass ribbon is reduced (hereinafter, referred to as a “width reduction phenomenon”). May occur. This is a phenomenon that occurs when the glass ribbon shrinks in the width direction due to surface tension.
　このような縮幅現象は、成形されるガラスリボン、さらには製造される板ガラスの幅寸法の精度を低下させるおそれがある。 Such a width reduction phenomenon may reduce the accuracy of the width dimension of the glass ribbon to be formed and further, the sheet glass to be manufactured.
　これに対して、本発明の一実施形態による板ガラスの製造方法では、ガラスリボンを成形する工程において、溶融ガラスは、板ガラスの失透温度ＴＬから軟化点ＴＳまでの平均冷却速度が１５００℃／分以上となるように冷却される。 In contrast, in the method for manufacturing a glass sheet according to the embodiment of the present invention, in the step of forming the glass ribbon, the molten glass has an average cooling rate from the devitrification temperature TL of the glass sheet to the softening point T S of 1500 ° C. / Minute or more.
　このような軟化点Ｔｓまでの急速な冷却のため、本発明の一実施形態による板ガラスの製造方法では、ガラスリボンの縮幅現象を有意に抑制することができるという、追加の効果を得ることができる。 Due to such rapid cooling to the softening point Ts, the sheet glass manufacturing method according to one embodiment of the present invention can obtain an additional effect that the width reduction phenomenon of the glass ribbon can be significantly suppressed. it can.
　例えば、ガラスリボンの縮幅量ΔＷを、
 
　　ΔＷ＝Ｗ１－Ｗ２
 
で表した場合、本発明の一実施形態による板ガラスの製造方法では、ガラスリボンの縮幅量ΔＷを５０ｍｍ以下とすることができる。 For example, the reduction width ΔW of the glass ribbon is

ΔW = W1-W2

In the method of manufacturing a glass sheet according to the embodiment of the present invention, the width ΔW of the glass ribbon can be reduced to 50 mm or less.
　ここで、Ｗ１は、成形開始直後、すなわち、自由落下開始直後のガラスリボンの幅である。また、Ｗ２は、成形完了直後のガラスリボンの幅である。一般には、Ｗ１は、成形開始温度における粘性でのガラスリボンの幅であり、Ｗ２は、粘性が約１０７．６５ポアズ程度になるときのガラスリボンの幅である。 Here, W1 is the width of the glass ribbon immediately after the start of molding, that is, immediately after the start of free fall. W2 is the width of the glass ribbon immediately after completion of molding. In general, W1 is the width of the glass ribbon at the viscosity at the molding start temperature, and W2 is the width of the glass ribbon when the viscosity is about 107.65 poise.
　縮幅量ΔＷは、４０ｍｍ以下であることが好ましい。 The amount of reduction ΔW is preferably 40 mm or less.
　（本発明の一実施形態による板ガラスの製造方法）
　次に、図３を参照して、本発明の一実施形態による板ガラスの製造方法について、より詳しく説明する。 (Method for Producing Sheet Glass According to One Embodiment of the Present Invention)
Next, with reference to FIG. 3, a method for manufacturing a sheet glass according to an embodiment of the present invention will be described in more detail.
　図３には、本発明の一実施形態による板ガラスの製造方法（以下、「第１の製造方法」と称する）のフローを概略的に示す。 FIG. 3 schematically shows a flow of a method for manufacturing a sheet glass (hereinafter, referred to as “first manufacturing method”) according to an embodiment of the present invention.
　図３に示すように、第１の製造方法は、
　（１）ガラス原料を溶解して、溶融ガラスを得る工程（工程Ｓ１１０）と、
　（２）前記溶融ガラスから、ガラスリボンを成形する工程（工程Ｓ１２０）と、
　（３）前記ガラスリボンを徐冷する工程（工程Ｓ１３０）と、
　（４）徐冷された前記ガラスリボンを切断し、板ガラスとする工程（工程Ｓ１４０）と、
　を有する。 As shown in FIG. 3, the first manufacturing method includes:
(1) a step of melting a glass raw material to obtain a molten glass (step S110);
(2) a step of forming a glass ribbon from the molten glass (step S120);
(3) a step of gradually cooling the glass ribbon (step S130);
(4) a step of cutting the gradually cooled glass ribbon to form a sheet glass (step S140);
Having.
　以下、各工程について説明する。 Hereinafter, each step will be described.
　（工程Ｓ１１０）
　まず、板ガラス用のガラス原料が準備される。 (Step S110)
First, a glass raw material for a sheet glass is prepared.
　ガラス原料の組成は、特に限られない。ただし、第１の製造方法では、比較的高い失透温度ＴＬ、すなわち低い失透粘性ηＬを有する組成の板ガラス用のガラス原料も、有意に使用することができる。 The composition of the glass raw material is not particularly limited. However, in the first manufacturing method, a glass raw material for a sheet glass having a composition having a relatively high devitrification temperature T L , that is, a low devitrification viscosity η L can also be used significantly.
　次に、ガラス原料が溶解炉に供給され、溶融ガラスが形成される。 Next, the glass raw material is supplied to the melting furnace to form molten glass.
　溶解温度は、特に限られないが、例えば、ガラスの粘度が１００～１０３ポアズとなるような温度であっても良い。 The melting temperature is not particularly limited, but may be, for example, a temperature at which the viscosity of the glass becomes 10 0 to 10 3 poise.
　例えば、ガラス原料から製造される板ガラスの失透温度ＴＬは、８００℃以上であっても良く、８５０℃以上であっても良く、９００℃以上であっても良い。また、失透温度ＴＬと粘性が１０４ｄＰａ・ｓとなる温度である作業温度ＴＷとの差、ＴＬ－Ｔｗは特に限定されないが、０℃以上であるのが好ましく、５０℃以上であるのが好ましく、１００℃以上であるのがさらに好ましい。 For example, the devitrification temperature TL of the plate glass manufactured from the glass raw material may be 800 ° C. or higher, 850 ° C. or higher, or 900 ° C. or higher. The difference between the devitrification temperature T L and the working temperature T W at which the viscosity becomes 10 4 dPa · s, T L −T w, is not particularly limited, but is preferably 0 ° C. or more, and is preferably 50 ° C. It is preferably at least 100 ° C., more preferably at least 100 ° C.
　また、ガラス原料から製造される板ガラスの軟化点ＴＳは、特に限られないが、例えば４００℃～１１００℃の範囲であっても良い。 Further, the softening point T S of the plate glass produced from the glass raw material is not particularly limited, but may be, for example, in the range of 400 ° C. to 1100 ° C.
　また、ガラス原料から製造される板ガラスの失透粘性ηＬは、例えば１×１００～１×１０５ｄＰａ・ｓ（ポアズ）の範囲であり、１×１０１．５～１×１０４ｄＰａ・ｓ（ポアズ）の範囲であることが好ましく、１×１０２～１×１０３ｄＰａ・ｓ（ポアズ）の範囲であることがより好ましい。 Further, the devitrification viscosity η L of the plate glass produced from the glass raw material is, for example, in the range of 1 × 10 0 to 1 × 10 5 dPa · s (poise), and 1 × 10 1.5 to 1 × 10 4 dPa. S (poise), more preferably 1 × 10 2 to 1 × 10 3 dPa · s (poise).
　溶解炉の溶融ガラスは、その後成形工程に移送される。 溶 融 The molten glass in the melting furnace is then transferred to the forming process.
　（工程Ｓ１２０）
　次に、成形工程が実施される。この工程では、溶解炉から移送された溶融ガラスが成形され、ガラスリボンが成形される。 (Step S120)
Next, a molding step is performed. In this step, the molten glass transferred from the melting furnace is formed, and a glass ribbon is formed.
　前述のように、第１の製造方法では、溶融ガラスは、失透温度ＴＬから軟化点ＴＳまでの平均冷却速度ｖｉが１５００℃／分以上となるように冷却される。 As described above, in the first manufacturing method, the molten glass, the average cooling rate v i from devitrification temperature T L to the softening point T S is cooled so that the 1500 ° C. / min or more.
　失透温度ＴＬから軟化点ＴＳまでの平均冷却速度ｖｉは、例えば、１８００℃／分以上であり、２０００℃／分以上であることが好ましい。 The average cooling rate v i from devitrification temperature T L to the softening point T S is, for example, 1800 ° C. / min or more and 2000 ° C. / min or more.
　このようなガラスリボンの「急冷」を実施する方法は、特に限られない。 方法 The method of performing such “quenching” of the glass ribbon is not particularly limited.
　例えば、ガラスリボンに、冷却ガスを吹き付けることにより、ガラスリボンを急冷しても良い。以下、このような急冷方法を、特に、「ガスブロー冷却法」と称する。 For example, the glass ribbon may be rapidly cooled by spraying a cooling gas on the glass ribbon. Hereinafter, such a rapid cooling method is particularly referred to as a “gas blow cooling method”.
　ガスブロー冷却法に使用されるガスは、ガラスリボンに悪影響を及ぼさない限り、特に限られない。例えば、アルゴンおよび窒素のような不活性ガス、または空気などを冷却ガスとして使用しても良い。 ガ ス The gas used in the gas blow cooling method is not particularly limited as long as it does not adversely affect the glass ribbon. For example, an inert gas such as argon and nitrogen, or air may be used as the cooling gas.
　また、ガスブロー冷却法では、十分に低い温度に維持されたガスを吹き付けることが好ましい。特に、吹き付けるガスの温度は、溶融ガラスの軟化点ＴＳよりも低くすることが好ましい。例えば、吹き付けるガスの温度は、溶融ガラスの軟化点ＴＳよりも１℃～１００℃低くすることが好ましい。 In the gas blow cooling method, it is preferable to blow a gas maintained at a sufficiently low temperature. In particular, the temperature of the blown gas is preferably lower than the softening point T S of the molten glass. For example, it is preferable that the temperature of the blown gas be lower by 1 ° C. to 100 ° C. than the softening point T S of the molten glass.
　図４には、ガスブロー冷却法により、ガラスリボンを冷却する際に使用される装置の一構成例を模式的に示す。 FIG. 4 schematically shows an example of a configuration of an apparatus used for cooling a glass ribbon by a gas blow cooling method.
　図４に示すように、この構成例では、装置１００は、収容部材１１０およびガス供給部材１２５を有する。 As shown in FIG. 4, in this configuration example, the device 100 has a housing member 110 and a gas supply member 125.
　収容部材１１０は、上部部材１１２と、底部部材１１５とを有する。 The housing member 110 has an upper member 112 and a bottom member 115.
　上部部材１１２は、上面１１２ａと、該上面１１２ａを取り囲む４つの側面１１２ｂとを有する。上面１１２ａには上側が開放された凹部１１４が形成されている。また、対向する２つの側面１１２ｂは、鉛直方向（紙面の下向きの方向）、および紙面に対して垂直な方向に沿って、相互に平行に延在している。 The upper member 112 has an upper surface 112a and four side surfaces 112b surrounding the upper surface 112a. A concave portion 114 whose upper side is opened is formed in the upper surface 112a. The two opposing side surfaces 112b extend parallel to each other in a vertical direction (a downward direction on the paper) and in a direction perpendicular to the paper.
　一方、収容部材１１０の底部部材１１５は、断面略逆三角形状となっており、２つの斜面１１６ａ、１１６ｂと、両斜面をつなぐ頂点１１６ｃとを有する。第１の斜面１１６ａ、第２の斜面１１６ｂ、および頂点１１６ｃは、それぞれ、紙面に対して垂直な方向にも延伸しており、従って、収容部材１１０の下部は、略三角柱形状を有する。 On the other hand, the bottom member 115 of the housing member 110 has a substantially inverted triangular cross section, and has two slopes 116a and 116b and an apex 116c connecting both slopes. The first inclined surface 116a, the second inclined surface 116b, and the apex 116c also extend in a direction perpendicular to the paper surface, and therefore, the lower portion of the housing member 110 has a substantially triangular prism shape.
　第１の斜面１１６ａの上部は、上部部材１１２の一つの側面１１２ｂと接続されており、第２の斜面１１６ｂの上部は、上部部材１１２の一つの側面１１２ｂと接続されている。 上部 The upper part of the first slope 116a is connected to one side surface 112b of the upper member 112, and the upper part of the second slope 116b is connected to one side surface 112b of the upper member 112.
　ガス供給部材１２５は、１または２以上のノズルを有する。例えば、図４に示した例では、ガス供給部材１２５は、左右対称な位置に配置された第１組のノズル１２７ａおよび１２７ｂと、左右対称な位置に配置された第２組のノズル１２９ａおよび１２９ｂとを備える。 The gas supply member 125 has one or more nozzles. For example, in the example shown in FIG. 4, the gas supply member 125 includes a first set of nozzles 127a and 127b arranged at symmetric positions and a second set of nozzles 129a and 129b arranged at symmetric positions. And
　第１組のノズル１２７ａ、１２７ｂと、第２組のノズル１２９ａおよび１２９ｂとは、相互に異なる高さ位置に設置されている。 The first set of nozzles 127a and 127b and the second set of nozzles 129a and 129b are installed at mutually different heights.
　なお、図４に示した例では、ガス供給部材１２５は、合計４つのノズル１２７ａ、１２７ｂ、１２９ａ、１２９ｂを有する。ただし、これは単なる一例であって、ノズルの数および配置は、ガラスリボンが適正に冷却できる限り、特に限られない。 In the example shown in FIG. 4, the gas supply member 125 has a total of four nozzles 127a, 127b, 129a, and 129b. However, this is only an example, and the number and arrangement of the nozzles are not particularly limited as long as the glass ribbon can be appropriately cooled.
　このような装置１００を使用して、ガスブロー冷却法により溶融ガラスを冷却する場合、収容部材１１０の上部部材１１２の凹部１１４に、溶融ガラス１５０が供給される。 When the molten glass is cooled by the gas blow cooling method using such an apparatus 100, the molten glass 150 is supplied to the concave portion 114 of the upper member 112 of the housing member 110.
　凹部１１４は、溶融ガラス１５０を収容する。ただし、凹部１１４の収容容積を超える溶融ガラス１５０が供給されると、溶融ガラス１５０は、収容部材１１０の対向する側面１１２ｂに沿って溢れ出し、第１の溶融ガラス部分１５２ａおよび第２の溶融ガラス部分１５２ｂとなる。 The recess 114 accommodates the molten glass 150. However, when the molten glass 150 that exceeds the storage volume of the recess 114 is supplied, the molten glass 150 overflows along the opposite side surface 112b of the storage member 110, and the first molten glass portion 152a and the second molten glass 150 It becomes the part 152b.
　その後、第１の溶融ガラス部分１５２ａは、収容部材１１０の第１の斜面１１６ａに沿って、さらに下方に流れる。同様に、第２の溶融ガラス部分１５２ｂは、収容部材１１０の第２の斜面１１６ｂに沿って、さらに下方に流れる。 After that, the first molten glass portion 152a flows further downward along the first slope 116a of the housing member 110. Similarly, the second molten glass portion 152b flows further downward along the second slope 116b of the housing member 110.
　その結果、第１の溶融ガラス部分１５２ａおよび第２の溶融ガラス部分１５２ｂは、頂点１１６ｃに至り、ここで一体化される。 As a result, the first molten glass portion 152a and the second molten glass portion 152b reach the vertex 116c and are integrated there.
　その後、合体した溶融ガラスは、ガラスリボン１７０となって、さらに鉛直方向に進展する。すなわち、頂点１１６ｃが成形開始位置となり、ここからガラスリボン１７０の成形が開始される。 (4) Thereafter, the combined molten glass becomes a glass ribbon 170 and further extends in the vertical direction. That is, the vertex 116c is the molding start position, and the molding of the glass ribbon 170 is started from here.
　ここで、装置１００は、ガラスリボン１７０の、特に成形開始位置（頂点１１６ｃ）に近接する位置に、ガス供給部材１２５を有する。このガス供給部材１２５の各ノズル１２７ａ、１２７ｂ、１２９ａ、１２９ｂから、ガラスリボン１７０に向かって冷却ガスが吹きつけられる。 Here, the apparatus 100 has the gas supply member 125 at a position close to the glass ribbon 170, particularly at a position where the forming is started (the vertex 116 c). A cooling gas is blown toward the glass ribbon 170 from each of the nozzles 127a, 127b, 129a, and 129b of the gas supply member 125.
　従って、装置１００では、溶融ガラス１５０の成形開始直後から、ガラスリボン１７０を急冷することができる。 Therefore, the apparatus 100 can rapidly cool the glass ribbon 170 immediately after the start of forming the molten glass 150.
　なお、図４に示した装置１００の構成例は、単なる一例であって、別の装置を用いてガスブロー冷却法を実施しても良い。 The configuration example of the apparatus 100 shown in FIG. 4 is merely an example, and the gas blow cooling method may be performed using another apparatus.
　また、別の冷却方法として、冷却されたロールにガラスリボンを連続的に接触させることにより、ガラスリボンを急冷しても良い。以下、このような急冷方法を「ロール冷却法」と称する。 As another cooling method, the glass ribbon may be rapidly cooled by continuously bringing the glass ribbon into contact with the cooled roll. Hereinafter, such a rapid cooling method is referred to as a “roll cooling method”.
　ロール冷却法では、例えば十分に低い温度に維持されたロールを使用することが好ましい。特に、ロールの温度は溶融ガラスの軟化点ＴＳよりも低くすることが好ましい。例えば、ロールの温度は、溶融ガラスの軟化点ＴＳよりも１℃～１００℃低くすることが好ましい。 In the roll cooling method, for example, it is preferable to use a roll maintained at a sufficiently low temperature. In particular, it is preferable that the temperature of the roll is lower than the softening point T S of the molten glass. For example, it is preferable that the temperature of the roll is 1 ° C. to 100 ° C. lower than the softening point T S of the molten glass.
　ロールの冷却方法としては、低い温度の水、気体、油等を循環させて冷却する水冷、空冷、油冷等の方法が挙げられる。 (4) Examples of the method for cooling the roll include water cooling, air cooling, and oil cooling in which low-temperature water, gas, and oil are circulated for cooling.
　図５には、ロール冷却法により、ガラスリボンを冷却する際に使用される装置の一構成例を模式的に示す。 FIG. 5 schematically shows an example of a configuration of an apparatus used for cooling a glass ribbon by a roll cooling method.
　図５に示すように、この構成例では、ロール冷却法を実施する装置３００は、収容部材３１０と、少なくとも一組の冷却ロール３６０とを備える。なお、図５には示されていないが、装置３００は、さらに、冷却ロール３６０の下流側に搬送ローラおよび徐冷炉を有する。搬送ローラは、冷却ロール３６０から送り出されるガラスリボン３７０を引き出し、徐冷炉に導入する役割を有する。 As shown in FIG. 5, in this configuration example, the apparatus 300 for performing the roll cooling method includes the housing member 310 and at least one pair of cooling rolls 360. Although not shown in FIG. 5, the apparatus 300 further includes a transport roller and an annealing furnace downstream of the cooling roll 360. The transport roller has a role of drawing out the glass ribbon 370 sent from the cooling roll 360 and introducing the glass ribbon 370 into the lehr.
　収容部材３１０は、溶解炉（図示されていない）から供給される溶融ガラス３５０を収容し、収容しきれなかった溶融ガラス３５０を下方にオーバーフローさせる役割を有する。収容部材３１０は、前述の図４に示した収容部材１１０のような形態を有しても良い。 The storage member 310 has a role of storing the molten glass 350 supplied from a melting furnace (not shown) and overflowing the molten glass 350 that could not be stored downward. The housing member 310 may have a form like the housing member 110 shown in FIG. 4 described above.
　このような装置３００を用いて板ガラスを製造する場合、まず、溶融ガラス３５０が収容部材３１０の上部に供給される。 In the case of manufacturing a sheet glass using such an apparatus 300, first, the molten glass 350 is supplied to the upper part of the housing member 310.
　収容部材３１０に収容しきれずオーバーフローした溶融ガラス３５０は、収容部材３１０の対向する２つの側面に沿って流下し、合流点３２０で合流することにより、ガラスリボン３７０となる。 溶 融 Molten glass 350 that cannot be accommodated in accommodation member 310 and overflows flows down along two opposing side surfaces of accommodation member 310 and joins at junction 320 to form glass ribbon 370.
　その後、ガラスリボン３７０は、さらに下方に流れ、２つの冷却ロール３６０に挟まれて支持される。冷却ロール３６０は、前述のように、水、気体、または油等により、所定の温度に維持されており、冷却ロール３６０と接触したガラスリボン３７０は、ここで急冷される。 Thereafter, the glass ribbon 370 flows further downward and is supported by being sandwiched between the two cooling rolls 360. As described above, the cooling roll 360 is maintained at a predetermined temperature by water, gas, oil, or the like, and the glass ribbon 370 in contact with the cooling roll 360 is rapidly cooled here.
　前述のように、冷却ロール３６０の下流には、搬送ローラ（図示されていない）が設置されている。この搬送ローラにより、ガラスリボン３７０は、冷却ロール３６０の下流側に引き出され、徐冷炉に導入される。 As described above, a transport roller (not shown) is provided downstream of the cooling roll 360. With this transport roller, the glass ribbon 370 is pulled out to the downstream side of the cooling roll 360 and introduced into the lehr.
　徐冷炉に導入されたガラスリボン３７０は、徐々に冷却され、所定の温度になった際に、所定の寸法に切断され、板ガラスが製造される。 ガ ラ ス The glass ribbon 370 introduced into the annealing furnace is gradually cooled, and when it reaches a predetermined temperature, is cut into a predetermined size to produce a sheet glass.
　このように、装置３００では、冷却ロール３６０を利用して、ガラスリボン３７０を急冷することができる。 Thus, in the apparatus 300, the glass ribbon 370 can be rapidly cooled using the cooling roll 360.
　また、さらに別の冷却方法として、溶融ガラスに液体を吹きつける方法が挙げられる。例えば、溶融ガラスの成形開始温度（作業点ＴＷ）またはその近傍の温度領域で、比較的気化し易い液体を、吹きつけ液体として使用することにより、ガラスリボンを急冷することができる。以下、このような急冷方法を、特に、「液体吹きつけ冷却法」と称する。 Further, as another cooling method, there is a method of spraying a liquid onto molten glass. For example, a glass ribbon can be rapidly cooled by using a relatively vaporizable liquid as a spray liquid at a forming temperature of the molten glass (working point T W ) or a temperature region in the vicinity thereof. Hereinafter, such a rapid cooling method is particularly referred to as a “liquid spray cooling method”.
　液体吹きつけ冷却法に使用され得る液体としては、例えば、水、エタノールおよびアセトンなどが挙げられる。これらの液体は、ガラスリボンと接触しても、ガラスリボンに悪影響を及ぼす可能性は低い。吹き付ける液体の温度は、溶融ガラスの軟化点ＴＳよりも低くすることが好ましい。 Liquids that can be used in the liquid spray cooling method include, for example, water, ethanol, acetone, and the like. These liquids are less likely to adversely affect the glass ribbon, even when in contact with the glass ribbon. The temperature of the liquid to be sprayed is preferably lower than the softening point T S of the molten glass.
　また、別の冷却方法として、ガラスリボンを、連続的に溶融金属浴上に落下させることにより、ガラスリボンを急冷しても良い。冷却源となる溶融金属としては、これに限られるものではないが、スズ、鉛、亜鉛、水銀、および銅などが挙げられる。なお、溶融金属は、単一の金属であっても、前述の金属群から選ばれる２種以上の合金であっても良い。溶融金属の温度は、溶融ガラスの軟化点ＴＳよりも低くすることが好ましい。例えば、溶融金属の温度は、溶融ガラスの軟化点ＴＳよりも１℃～１００℃低くすることが好ましい。 Further, as another cooling method, the glass ribbon may be rapidly cooled by continuously dropping the glass ribbon onto a molten metal bath. The molten metal serving as a cooling source includes, but is not limited to, tin, lead, zinc, mercury, copper, and the like. The molten metal may be a single metal or an alloy of two or more selected from the above-described metal group. The temperature of the molten metal is preferably lower than the softening point T S of the molten glass. For example, it is preferable that the temperature of the molten metal is 1 ° C. to 100 ° C. lower than the softening point T S of the molten glass.
　以上のような方法で、溶融ガラスが急冷され、ガラスリボンが成形される。 The molten glass is quenched and the glass ribbon is formed by the above method.
　成形工程におけるガラスリボンのこのような急冷処理により、溶融ガラスが失透温度ＴＬを通過する時間が有意に短くなる。またその結果、比較的高い失透温度ＴＬ、すなわち低い失透粘性ηＬを有するガラスから板ガラスを製造する場合であっても、成形過程において、ガラスリボンに失透現象が生じる可能性を、有意に抑制することができる。 Such rapid cooling of the glass ribbon in the forming step significantly reduces the time for the molten glass to pass through the devitrification temperature TL . Further, as a result, even when a sheet glass is manufactured from glass having a relatively high devitrification temperature T L , that is, a glass having a low devitrification viscosity η L , there is a possibility that a devitrification phenomenon occurs in the glass ribbon in the forming process. It can be suppressed significantly.
　（工程Ｓ１３０）
　次に、成形されたガラスリボンが徐冷される。通常の場合、この工程は、徐冷炉内で実施される。 (Step S130)
Next, the formed glass ribbon is gradually cooled. Usually, this step is performed in a lehr.
　通常の場合、徐冷炉に供給されるガラスリボンの温度は、徐冷点ＴＡの前後である。これは、ガラスの粘度で表せば、１０１３ポアズ程度となる。 Normally, the temperature of the glass ribbon to be supplied to the annealing furnace is a front and rear annealing point T A. This is about 10 13 poise in terms of the viscosity of glass.
　徐冷点ＴＡは、例えば、４５０℃～７００℃の範囲である。 The annealing point T A is, for example, in the range of 450 ° C. to 700 ° C.
　（工程Ｓ１４０）
　その後、ガラスリボンは所定の寸法で切断される。 (Step S140)
Thereafter, the glass ribbon is cut to predetermined dimensions.
　以上の工程により、所望の寸法形状の板ガラスを製造することができる。 板 Through the above steps, a sheet glass having a desired size and shape can be manufactured.
　製造される板ガラスの屈折率は、例えば、１．４０～２．２０の範囲であっても良い。このうち、高屈折率が必要な場合には、１．６０以上が好ましく、１．６５以上がより好ましく、１．７０以上がさらに好ましく、１．７５以上が特に好ましい。このような高屈折率の板ガラスは、例えば、高性能な液晶パネル等の映像表示機器、発光デバイスの光取り出し部材等に適用することができる。一方、低分散性や異常分散性、特定の波長をカットするフィルタ用途、例えば近赤外域の光をカットするのが必要な場合には、１．５０以下が好ましく、１．４８以下が好ましく、１．４５以下がさらに好ましい。このような低屈折率のガラスは、撮像素子における視感度補正や、撮像用光学系の色収差の補正に用いることができる。 (4) The refractive index of the manufactured glass sheet may be, for example, in the range of 1.40 to 2.20. Among these, when a high refractive index is required, it is preferably 1.60 or more, more preferably 1.65 or more, still more preferably 1.70 or more, and particularly preferably 1.75 or more. Such a high-refractive-index plate glass can be applied to, for example, a video display device such as a high-performance liquid crystal panel, a light extraction member of a light emitting device, and the like. On the other hand, low dispersion or anomalous dispersion, filter applications to cut a specific wavelength, for example, when it is necessary to cut light in the near infrared region, 1.50 or less, preferably 1.48 or less, 1.45 or less is more preferable. Such a low-refractive-index glass can be used for correcting visibility in an image pickup device and correcting chromatic aberration of an image pickup optical system.
　また、製造される板ガラスのヤング率は、例えば、９０ＧＰａ～１５０ＧＰａの範囲であっても良い。ヤング率は、９５ＧＰａ以上が好ましく、１００ＧＰａ以上がより好ましく、１０５ＧＰａ以上がさらに好ましく１１０ＧＰａ以上が特に好ましい。このようなガラスは、例えば情報記録用磁気ディスクの基板や、ディスプレイ用の基板、半導体パッケージング用の支持ガラス、ファンアウトプロセス用のキャリアガラス、モバイル情報デバイス用のカバーガラスなどに適用することができる。 The manufactured sheet glass may have a Young's modulus in a range of, for example, 90 GPa to 150 GPa. The Young's modulus is preferably 95 GPa or more, more preferably 100 GPa or more, further preferably 105 GPa or more, and particularly preferably 110 GPa or more. Such a glass can be applied to, for example, a substrate of a magnetic disk for information recording, a substrate for a display, a support glass for semiconductor packaging, a carrier glass for a fan-out process, a cover glass for a mobile information device, and the like. it can.
　以下、本発明の実施例について説明する。 Hereinafter, embodiments of the present invention will be described.
　（例１）
　以下の方法で、板ガラスの製造試験を実施した。 (Example 1)
A production test of a sheet glass was performed by the following method.
　図４には、試験に使用した板ガラスの製造装置の一部を概略的に示す。 FIG. 4 schematically shows a part of a plate glass manufacturing apparatus used for the test.
　図４に示すように装置１００は、収容部材１１０と、ガス供給部材１２５とを備える。なお、図４には示されていないが、装置１００は、さらにガス供給部材１２５の下流側に徐冷部を有する。 装置 As shown in FIG. 4, the device 100 includes a housing member 110 and a gas supply member 125. Although not shown in FIG. 4, the apparatus 100 further includes a slow cooling unit downstream of the gas supply member 125.
　収容部材１１０は、溶解炉（図示されていない）から供給される溶融ガラスを収容し、収容しきれなかった溶融ガラスを下方にオーバーフローさせる役割を有する。 The storage member 110 has a role of storing the molten glass supplied from the melting furnace (not shown) and overflowing the molten glass that cannot be stored downward.
　このような装置１００を用いて板ガラスを製造する場合、まず、溶融ガラス１５０が収容部材１１０の上部に供給される。 In the case of manufacturing a sheet glass using such an apparatus 100, first, the molten glass 150 is supplied to the upper part of the housing member 110.
　収容部材１１０の上部部材１１２の凹部１１４に、溶融ガラス１５０が供給される。 (4) The molten glass 150 is supplied to the concave portion 114 of the upper member 112 of the housing member 110.
　凹部１１４は、溶融ガラス１５０を収容する。ただし、凹部１１４の収容容積を超える溶融ガラス１５０が供給されて、溶融ガラス１５０が、収容部材１１０の対向する側面１１２ｂに沿って溢れ出し、第１の溶融ガラス部分１５２ａおよび第２の溶融ガラス部分１５２ｂとなる。 The recess 114 accommodates the molten glass 150. However, the molten glass 150 that exceeds the storage volume of the concave portion 114 is supplied, and the molten glass 150 overflows along the opposite side surface 112b of the storage member 110, and the first molten glass portion 152a and the second molten glass portion 152b.
　その後、第１の溶融ガラス部分１５２ａは、収容部材１１０の第１の斜面１１６ａに沿って、さらに下方に流れる。同様に、第２の溶融ガラス部分１５２ｂは、収容部材１１０の第２の斜面１１６ｂに沿って、さらに下方に流れる。 After that, the first molten glass portion 152a flows further downward along the first slope 116a of the housing member 110. Similarly, the second molten glass portion 152b flows further downward along the second slope 116b of the housing member 110.
　その結果、第１の溶融ガラス部分１５２ａおよび第２の溶融ガラス部分１５２ｂは、頂点１１６ｃに至り、ここで一体化される。 As a result, the first molten glass portion 152a and the second molten glass portion 152b reach the vertex 116c and are integrated there.
　その後、合体した溶融ガラスは、ガラスリボン１７０となって、さらに鉛直方向に進展する。すなわち、頂点１１６ｃが成形開始位置となり、ここからガラスリボン１７０の成形が開始される。 (4) Thereafter, the combined molten glass becomes a glass ribbon 170 and further extends in the vertical direction. That is, the vertex 116c is the molding start position, and the molding of the glass ribbon 170 is started from here.
　次に、成形開始位置（頂点１１６ｃ）に近接する位置に設置されたガス供給部材１２５の各ノズル１２７ａ、１２７ｂ、１２９ａ、１２９ｂから、ガラスリボン１７０に向かって冷却ガスを吹きつけ、ガラスリボン１７０を急冷する。なお、各ノズル１２７ａ、１２７ｂ、１２９ａ、１２９ｂは、ガラスリボン１７０に対して、冷却ガスが鉛直方向１００ｍｍの領域にわたって吹きつけられるように、位置および形状が調整されている。 Next, a cooling gas is blown toward the glass ribbon 170 from each of the nozzles 127a, 127b, 129a, and 129b of the gas supply member 125 installed at a position close to the molding start position (apex 116c). Quench quickly. The positions and shapes of the nozzles 127a, 127b, 129a, and 129b are adjusted such that the cooling gas is blown over the glass ribbon 170 over a region of 100 mm in the vertical direction.
　急冷されたガラスリボン１７０は、徐冷部に導入される。 The rapidly cooled glass ribbon 170 is introduced into the slow cooling unit.
　徐冷部に導入されたガラスリボン１７０は、徐々に冷却され、所定の温度になった際に、所定の寸法に切断され、板ガラスが製造される。 ガ ラ ス The glass ribbon 170 introduced into the slow cooling section is gradually cooled, and when it reaches a predetermined temperature, is cut into a predetermined size to produce a sheet glass.
　このような装置１００を使用して、板ガラスの製造試験を実施した。 板 Using such an apparatus 100, a production test of a sheet glass was performed.
　使用した溶融ガラス１５０は、作業点ＴＷ（粘度η＝１０４ポアズ）が８７０℃であり、失透温度ＴＬが約１０５０℃（失透粘性ηＬ＝１．１×１０２ポアズ）であり、軟化点ＴＳ（粘度η＝１０７．６５ポアズ）が約６８０℃であり、徐冷点ＴＡ（粘度η＝１０１３ポアズ）が５８０℃であった。 Molten glass 150 used was working point T W (viscosity eta = 10 4 poise) and is 870 ° C., at a devitrification temperature T L of approximately 1050 ° C. (devitrification viscosity η L = 1.1 × 10 2 poise) The sample had a softening point T S (viscosity η = 10 7.65 poise) of about 680 ° C. and an annealing point T A (viscosity η = 10 13 poise) of 580 ° C.
　収容部材１１０に供給される溶融ガラス１５０の温度は、約１１００℃とした。また、頂点１１６ｃにおける溶融ガラス１５０（ガラスリボン１７０）の温度（以下、「Ｔ１（℃）」と称する）は、１０６０℃であった。 The temperature of the molten glass 150 supplied to the housing member 110 was about 1100 ° C. The temperature of the molten glass 150 (glass ribbon 170) at the vertex 116c (hereinafter, referred to as “T 1 (° C.)”) was 1,060 ° C.
　ガス供給部材１２５の各ノズル１２７ａ、１２７ｂ、１２９ａ、１２９ｂからは冷却ガスである温度３０℃の空気をガラスリボン１７０に吹き付け、ガラスリボン１７０を急冷した。このときのガラスリボン１７０の搬送速度は、３００ｍｍ／分とした。またこのときのガラスリボン１７０の厚さは、約３．０ｍｍであった。またガス供給部材１２５のノズルの間を通過した直後のガラスリボン１７０の温度は６６０℃であった。 (4) Air having a temperature of 30 ° C., which is a cooling gas, was blown onto the glass ribbon 170 from each of the nozzles 127 a, 127 b, 129 a, and 129 b of the gas supply member 125 to rapidly cool the glass ribbon 170. The transport speed of the glass ribbon 170 at this time was 300 mm / min. At this time, the thickness of the glass ribbon 170 was about 3.0 mm. The temperature of the glass ribbon 170 immediately after passing between the nozzles of the gas supply member 125 was 660 ° C.
　このような条件において、ガラスリボン１７０が頂点１１６ｃにある時間をゼロ点（ｔ１）とし、ガラスリボン１７０がガス供給部材のノズルの間を通過した直後の温度（以下、「Ｔ２（℃）」と称する）、すなわち６６０℃になるまでの時間（「ｔ２（分）」と称する）を測定した。 Under such conditions, the time when the glass ribbon 170 is at the vertex 116c is set to a zero point (t 1 ), and the temperature immediately after the glass ribbon 170 passes between the nozzles of the gas supply member (hereinafter, “T 2 (° C.)”) ), That is, the time required to reach 660 ° C. (referred to as “t 2 (minute)”).
　得られた測定結果から、以下の式により、第２平均冷却速度ｖｉｉを算定した：
 
　　第２平均冷却速度ｖｉｉ（℃／分）＝（Ｔ１―Ｔ２）／ｔ２　　（１）式
 
　その結果、第２平均冷却速度ｖｉｉは、２１００℃／分であった。 From the obtained measurement results, the second average cooling rate v ii was calculated by the following equation:

Second average cooling rate v ii (° C./min)=(T 1 −T 2 ) / t 2 Equation (1)
As a result, the second average cooling rate v ii was 2100 ° C./min.
　なお、ガラスリボン１７０の失透温度ＴＬから軟化点ＴＳまでの平均冷却速度ｖｉは、第２平均冷却速度ｖｉｉと比べて、ｖｉ＞ｖｉｉの関係にある。従って、この試験において、平均冷却速度ｖｉが２１００℃／分を超えることは明らかである。 The average cooling rate v i from devitrification temperature T L of the glass ribbon 170 to the softening point T S, as compared with the second average cooling rate v ii, a relationship of v i> v ii. Therefore, in this test, it is clear that the average cooling rate v i exceeds 2100 ° C. / min.
　前述のように定められるガラスリボン１７０の縮幅量ΔＷを測定したところ、縮幅量ΔＷは、２５ｍｍであった。 と こ ろ When the width ΔW of the glass ribbon 170 determined as described above was measured, the width ΔW was 25 mm.
　試験後に得られた板ガラスを観察したところ、板ガラスに結晶化は認められなかった。 と こ ろ When the sheet glass obtained after the test was observed, no crystallization was observed in the sheet glass.
　（例２）
　例１と同様の方法により、板ガラスの製造試験を実施した。 (Example 2)
A production test of a sheet glass was carried out in the same manner as in Example 1.
　ただし、この例２では、ガラスリボン１７０の搬送速度は４００ｍｍ／分とした。そのときの、ガラスリボン１７０の厚さは、約２．２ｍｍであった。その他の条件は、例１の場合と同様である。 However, in Example 2, the transport speed of the glass ribbon 170 was 400 mm / min. At that time, the thickness of the glass ribbon 170 was about 2.2 mm. Other conditions are the same as in the case of Example 1.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、２３５０℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 2350 ° C./min.
　得られた板ガラスにおいて、結晶化の発生は認められなかった。 結晶 No crystallization was observed in the obtained plate glass.
　また、ガラスリボン１７０の縮幅量ΔＷは、２７ｍｍであった。 The amount of width ΔW of the glass ribbon 170 was 27 mm.
　（例３）
　例１と同様の方法により、板ガラスの製造試験を実施した。 (Example 3)
A production test of a sheet glass was carried out in the same manner as in Example 1.
　ただし、この例３では、ガラスリボン１７０の搬送速度は６００ｍｍ／分とした。そのときの、ガラスリボン１７０の厚さは、約１．５ｍｍであった。その他の条件は、例１の場合と同様である。 However, in Example 3, the transfer speed of the glass ribbon 170 was set to 600 mm / min. At that time, the thickness of the glass ribbon 170 was about 1.5 mm. Other conditions are the same as in the case of Example 1.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、２８５０℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 2850 ° C./min.
　得られた板ガラスにおいて、結晶化の発生は認められなかった。 結晶 No crystallization was observed in the obtained plate glass.
　また、ガラスリボン１７０の縮幅量ΔＷは、３２ｍｍであった。 Further, the width reduction ΔW of the glass ribbon 170 was 32 mm.
　（例４）
　以下の方法で、板ガラスの製造試験を実施した。 (Example 4)
A production test of a sheet glass was performed by the following method.
　製造装置として、前述の図５に示したような装置３００を使用した。 (5) The apparatus 300 shown in FIG. 5 was used as the manufacturing apparatus.
　使用した溶融ガラス３５０は、作業点ＴＷ（粘度η＝１０４ポアズ）が８７０℃であり、失透温度ＴＬが約１０５０℃（失透粘性ηＬ＝１．１×１０２ポアズ）であり、軟化点ＴＳ（粘度η＝１０７．６５ポアズ）が約６８０℃であり、徐冷点ＴＡ（粘度η＝１０１３ポアズ）が５８０℃であった。 Molten glass 350 used was working point T W (viscosity eta = 10 4 poise) and is 870 ° C., at a devitrification temperature T L of approximately 1050 ° C. (devitrification viscosity η L = 1.1 × 10 2 poise) The sample had a softening point T S (viscosity η = 10 7.65 poise) of about 680 ° C. and an annealing point T A (viscosity η = 10 13 poise) of 580 ° C.
　収容部材３１０に供給される溶融ガラス３５０の温度は、約１１００℃とした。また、合流点３２０における溶融ガラス３５０（ガラスリボン３７０）の温度（以下、「Ｔ１（℃）」と称する）は、１０６０℃であった。 The temperature of the molten glass 350 supplied to the housing member 310 was about 1100 ° C. The temperature of the molten glass 350 (glass ribbon 370) at the junction 320 (hereinafter, referred to as “T 1 (° C.)”) was 1,060 ° C.
　２つの冷却ロール３６０は、表面温度を６６０℃に保持し、冷却ロール３６０の表面でのガラスリボン３７０の搬送速度は、３００ｍｍ／分とした。２つの冷却ロール３６０の間を搬送されるガラスリボン３７０の厚さは、約３．０ｍｍであった。 (2) The surface temperature of the two cooling rolls 360 was maintained at 660 ° C., and the transport speed of the glass ribbon 370 on the surface of the cooling rolls 360 was 300 mm / min. The thickness of the glass ribbon 370 conveyed between the two cooling rolls 360 was about 3.0 mm.
　このような条件において、ガラスリボン３７０が合流点３２０にある時間をゼロ点（ｔ１）とし、ガラスリボン３７０の温度が冷却ロール３６０の温度（以下、「Ｔ２（℃）」と称する）、すなわち６６０℃になるまでの時間（「ｔ２（分）」と称する）を測定した。 Under such conditions, the time when the glass ribbon 370 is at the junction 320 is set to a zero point (t 1 ), and the temperature of the glass ribbon 370 is the temperature of the cooling roll 360 (hereinafter, referred to as “T 2 (° C.)”); That is, the time required to reach 660 ° C. (referred to as “t 2 (minute)”) was measured.
　なお、ガラスリボン３７０は、冷却ロール３６０と直接接触する位置では、冷却ロール３６０と接触した直後に、該冷却ロール３６０の温度Ｔ２まで急冷される。 The glass ribbon 370 is in a position in direct contact with the cooling roll 360, immediately after contact with the cooling roll 360, is quenched to a temperature T 2 of the said cooling roll 360.
　そこで、ここでは、ガラスリボン３７０の表面の温度が、冷却ロール３６０の温度Ｔ２とほぼ等しくなるまでの時間を、ｔ２（分）と規定した。 Therefore, here, the time until the surface temperature of the glass ribbon 370 becomes substantially equal to the temperature T 2 of the cooling roll 360 is defined as t 2 (minutes).
　得られた測定結果から、前述の（１）式により、第２平均冷却速度ｖｉｉを算定した。 From the obtained measurement results, the second average cooling rate v ii was calculated according to the aforementioned equation (1).
　その結果、第２平均冷却速度ｖｉｉは、２３５０℃／分であった。 As a result, the second average cooling rate v ii was 2350 ° C./min.
　なお、ガラスリボン３７０の失透温度ＴＬから軟化点ＴＳまでの平均冷却速度ｖｉは、第２平均冷却速度ｖｉｉと比べて、ｖｉ＞ｖｉｉの関係にある。従って、この試験において、平均冷却速度ｖｉが２３５０℃／分を超えることは明らかである。 The average cooling rate v i from devitrification temperature T L of the glass ribbon 370 to the softening point T S, as compared with the second average cooling rate v ii, a relationship of v i> v ii. Therefore, in this test, it is clear that the average cooling rate v i exceeds 2350 ° C. / min.
　試験後に得られた板ガラスを観察したところ、板ガラスに結晶化は認められなかった。 と こ ろ When the sheet glass obtained after the test was observed, no crystallization was observed in the sheet glass.
　また、ガラスリボン３７０の縮幅量ΔＷは、２０ｍｍであった。 The amount of width ΔW of the glass ribbon 370 was 20 mm.
　（例５）
　例４と同様の方法により、板ガラスの製造試験を実施した。 (Example 5)
A production test of a sheet glass was performed in the same manner as in Example 4.
　ただし、この例５では、ガラスリボン３７０の搬送速度は４００ｍｍ／分とした。そのときの、ガラスリボン３７０の厚さは、約２．２ｍｍであった。その他の条件は、例４の場合と同様である。 However, in Example 5, the transport speed of the glass ribbon 370 was 400 mm / min. At that time, the thickness of the glass ribbon 370 was about 2.2 mm. The other conditions are the same as in Example 4.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、３２００℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 3200 ° C./min.
　得られた板ガラスにおいて、結晶化の発生は認められなかった。 結晶 No crystallization was observed in the obtained plate glass.
　また、ガラスリボン３７０の縮幅量ΔＷは、２４ｍｍであった。 The amount of width ΔW of the glass ribbon 370 was 24 mm.
　（例６）
　例４と同様の方法により、板ガラスの製造試験を実施した。 (Example 6)
A production test of a sheet glass was performed in the same manner as in Example 4.
　ただし、この例６では、ガラスリボン３７０の搬送速度は６００ｍｍ／分とした。そのときの、ガラスリボン３７０の厚さは、約１．５ｍｍであった。その他の条件は、例４の場合と同様である。 However, in Example 6, the transport speed of the glass ribbon 370 was set to 600 mm / min. At that time, the thickness of the glass ribbon 370 was about 1.5 mm. The other conditions are the same as in Example 4.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、４０００℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 4000 ° C./min.
　得られた板ガラスにおいて、結晶化の発生は認められなかった。 結晶 No crystallization was observed in the obtained plate glass.
　また、ガラスリボン３７０の縮幅量ΔＷは、２９ｍｍであった。 Further, the width reduction ΔW of the glass ribbon 370 was 29 mm.
　（例７）
　ガス供給部材の代わりに、溶融スズ浴を用いてガラスリボンを冷却すること以外は例１と同様にして板ガラスの製造試験を実施した。溶融スズの温度を６６０℃に保持し、溶融スズ浴の表面でのガラスリボンの搬送速度は、４１０ｍｍ／分とした。ガラスリボンの厚さは、約２．２ｍｍであった。 (Example 7)
A sheet glass production test was performed in the same manner as in Example 1 except that the glass ribbon was cooled using a molten tin bath instead of the gas supply member. The temperature of the molten tin was maintained at 660 ° C., and the transport speed of the glass ribbon on the surface of the molten tin bath was 410 mm / min. The thickness of the glass ribbon was about 2.2 mm.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、１８００℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 1800 ° C./min.
　得られた板ガラスにおいて、結晶化の発生は認められなかった。 結晶 No crystallization was observed in the obtained plate glass.
　また、ガラスリボンの縮幅量ΔＷは、２５ｍｍであった。 The amount of width ΔW of the glass ribbon was 25 mm.
　（例８）
　例１と同様の方法により、板ガラスの製造試験を実施した。 (Example 8)
A production test of a sheet glass was carried out in the same manner as in Example 1.
　ただし、この例８では、ガラスリボン１７０の鉛直方向２０ｍｍの領域にわたって、冷却ガスが吹きつけられるように、各ノズルの形状および位置、ならびに各ノズルから吐出される冷却ガスの供給量を調整した。なお、単位面積あたりの冷却ガスの供給量は、例１と同じである。ガラスリボン１７０の搬送速度は６００ｍｍ／分とした。そのときの、ガラスリボン１７０の厚さは、約２．３ｍｍであった。その他の条件は、例１の場合と同様である。 However, in Example 8, the shape and position of each nozzle and the supply amount of the cooling gas discharged from each nozzle were adjusted so that the cooling gas was blown over the region of the glass ribbon 170 in the vertical direction of 20 mm. The supply amount of the cooling gas per unit area is the same as in Example 1. The transfer speed of the glass ribbon 170 was 600 mm / min. At that time, the thickness of the glass ribbon 170 was about 2.3 mm. Other conditions are the same as in the case of Example 1.
　製造試験の結果、前述の（１）式から得られる第２平均冷却速度ｖｉｉは、４２０℃／分であった。 As a result of the production test, the second average cooling rate v ii obtained from the above equation (1) was 420 ° C./min.
　得られた板ガラスには、結晶化が認められた。 結晶 Crystallization was observed in the obtained plate glass.
　また、ガラスリボンの縮幅量ΔＷは、８５ｍｍであった。 Further, the width ΔW of reduction of the glass ribbon was 85 mm.
　以下の表１には、各例における製造試験の結果をまとめて示した。 Table 1 below summarizes the results of the production tests in each example.
Figure JPOXMLDOC01-appb-T000001
 　このように、例１～例７では、ガラスリボンの失透温度ＴＬから軟化点ＴＳまでの平均冷却速度ｖｉを１５００℃／分以上にできることが確認された。また、作業点ＴＷ（または成形開始温度Ｔ１）と失透温度ＴＬが接近している場合であっても、ガラスリボンの平均冷却速度ｖｉを１５００℃／分以上とすることにより、溶融ガラスの結晶化が抑制されることが確認された。
Figure JPOXMLDOC01-appb-T000001
 Thus, in Examples 1 to 7, the average cooling rate v i from devitrification temperature T L of the glass ribbon to the softening point T S can to 1500 ° C. / min or more was confirmed. Further, even when the working point T W (or molding start temperature T 1) and the devitrification temperature T L is closer, by an average cooling rate v i of the glass ribbon between 1500 ° C. / min or more, It was confirmed that the crystallization of the molten glass was suppressed.
　また、例１～例７では、例８に比べて、ガラスリボンの縮幅量ΔＷが有意に抑制されることがわかった。 Further, in Examples 1 to 7, it was found that the amount of reduction ΔW of the glass ribbon was significantly suppressed as compared with Example 8.
　本願は、２０１８年８月９日に出願した日本国特許出願２０１８－１５０３８６号に基づく優先権を主張するものであり、同日本国出願の全内容を本願に参照により援用する。 This application claims the priority based on Japanese Patent Application No. 2018-150386 filed on August 9, 2018, the entire contents of which are incorporated herein by reference.
　１０　　　　従来のガラス温度のプロファイル
　１１　　　　ガラス温度のプロファイル
　１００　　　装置
　１１０　　　収容部材
　１１２　　　上部部材
　１１２ａ　　上面
　１１２ｂ　　側面
　１１４　　　凹部
　１１５　　　底部部材
　１１６ａ　　第１の斜面
　１１６ｂ　　第２の斜面
　１１６ｃ　　頂点
　１２５　　　ガス供給部材
　１２７ａ、１２７ｂ　第１組のノズル
　１２９ａ、１２９ｂ　第２組のノズル
　１５０　　　溶融ガラス
　１５２ａ　　第１の溶融ガラス部分
　１５２ｂ　　第２の溶融ガラス部分
　１７０　　　ガラスリボン
　３００　　　装置
　３１０　　　収容部材
　３２０　　　合流点
　３５０　　　溶融ガラス
　３６０　　　冷却ロール
　３７０　　　ガラスリボン 10 Conventional glass temperature profile 11 Glass temperature profile 100 Device 110 Housing member 112 Top member 112a Top surface 112b Side surface 114 Concave 115 Bottom member 116a First slope 116b Second slope 116c Apex 125 Gas supply member 127a, 127b First Set of nozzles 129a, 129b Second set of nozzles 150 Molten glass 152a First molten glass portion 152b Second molten glass portion 170 Glass ribbon 300 Device 310 Housing member 320 Junction point 350 Molten glass 360 Cooling roll 370 Glass ribbon

Claims (10)

  1. 　板ガラスの製造方法であって、
    　ガラス原料を溶解して、溶融ガラスを得る工程と、
    　前記溶融ガラスから、ガラスリボンを成形する工程と、
    　前記ガラスリボンを徐冷する工程と、
    　を有し、
    　前記ガラスリボンを成形する工程では、前記溶融ガラスは、前記板ガラスの失透温度ＴＬから軟化点ＴＳまでの平均冷却速度が１５００℃／分以上となるように冷却される、製造方法。     A method for manufacturing a sheet glass,
    Melting glass raw materials to obtain a molten glass,
    From the molten glass, forming a glass ribbon,
    Gradually cooling the glass ribbon,
    Has,
    The manufacturing method, wherein in the step of forming the glass ribbon, the molten glass is cooled such that the average cooling rate from the devitrification temperature TL to the softening point T S of the glass sheet becomes 1500 ° C./min or more.
  2. 　前記冷却は、前記ガラスリボンに冷却用ガスを供給することにより実施される、請求項１に記載の製造方法。 The method according to claim 1, wherein the cooling is performed by supplying a cooling gas to the glass ribbon.
  3. 　前記冷却は、前記溶融ガラスと接触した際に気化することが可能な液体を、前記ガラスリボンに吹き付けることにより実施される、請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the cooling is performed by spraying a liquid that can be vaporized when the glass ribbon comes into contact with the molten glass onto the glass ribbon.
  4. 　前記冷却は、軟化点Ｔｓよりも低い温度に維持された冷却ロールに、前記ガラスリボンを接触させることにより実施される、請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the cooling is performed by bringing the glass ribbon into contact with a cooling roll maintained at a temperature lower than the softening point Ts.
  5. 　前記冷却は、前記軟化点ＴＳよりも低い温度に維持された溶融金属に、前記ガラスリボンを接触させることにより実施される、請求項１に記載の製造方法。 The method according to claim 1, wherein the cooling is performed by bringing the glass ribbon into contact with a molten metal maintained at a temperature lower than the softening point T S.
  6. 　前記板ガラスは、前記失透温度ＴＬが８００℃以上である、請求項１乃至５のいずれか一つに記載の製造方法。 The method according to claim 1, wherein the sheet glass has the devitrification temperature TL of 800 ° C. or higher.
  7. 　前記板ガラスは、前記失透温度ＴＬと作業温度ＴＷとの差、ＴＬ－ＴＷが０℃以上である、請求項１乃至６のいずれか一つに記載の製造方法。 The plate glass, the difference between the devitrification temperature T L and the working temperature T W, T L -T W is 0 ℃ or method according to any one of claims 1 to 6.
  8. 　前記板ガラスは、前記軟化点ＴＳが６００℃以上である、請求項１乃至７のいずれか一つに記載の製造方法。 The manufacturing method according to claim 1, wherein the softening point T S of the sheet glass is 600 ° C. or higher.
  9. 　前記板ガラスは、徐冷点が４５０℃～７００℃の範囲である、請求項1乃至８のいずれか一つに記載の製造方法。 The method according to any one of claims 1 to 8, wherein the sheet glass has an annealing point in a range of 450 ° C to 700 ° C.
  10. 　前記板ガラスは、失透粘性が１×１０～１×１０５ｄＰａ・ｓの範囲である、請求項１乃至９のいずれか一つに記載の製造方法。 The method according to any one of claims 1 to 9, wherein the sheet glass has a devitrification viscosity in a range of 1 × 10 to 1 × 10 5 dPa · s.
PCT/JP2019/030038 2018-08-09 2019-07-31 Method for manufacturing plate glass WO2020031811A1 (en)

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