WO2015046115A1

WO2015046115A1 - Float glass manufacturing method

Info

Publication number: WO2015046115A1
Application number: PCT/JP2014/075015
Authority: WO
Inventors: 純一宮下; 亮祐加藤; 山中　一彦; 信彰井川
Original assignee: 旭硝子株式会社
Priority date: 2013-09-25
Filing date: 2014-09-22
Publication date: 2015-04-02
Also published as: JPWO2015046115A1; TW201514104A

Abstract

This float glass manufacturing method includes: a step for forming a molten glass into a glass ribbon by supplying the molten glass onto a molten metal; and a step for spraying, to the glass ribbon, a gas containing molecules each of which has a fluorine atom in the structure thereof. Total contact quantities of fluorine atoms vary in the width direction of the glass ribbon.

Description

Method for producing float glass

The present invention relates to a method for producing float glass.

In recent years, in flat panel display devices such as mobile phones or personal digital assistants (PDAs), personal computers, televisions, in-vehicle navigation display devices, etc., in order to enhance the protection and aesthetics of the display, the area is wider than the image display portion. A thin plate-like cover glass is disposed on the front surface of the display.

Such a flat panel display device is required to be lightweight and thin, and accordingly, a cover glass used for display protection is also required to be thin.

However, as the thickness of the cover glass is reduced, the strength decreases, and the cover glass itself may be broken due to falling in use or while carrying it, which plays the original role of protecting the display device. There is a problem that it becomes impossible.

For this reason, the conventional cover glass raises the damage resistance of the cover glass by forming the compressive-stress layer on the surface by chemically strengthening the glass manufactured by the float method (henceforth a float glass). .

It has been reported that the float glass is warped after chemical strengthening and the flatness is impaired (Patent Documents 1 to 3). The warpage includes a glass surface that is not in contact with a molten metal such as molten tin (hereinafter also referred to as a top surface) and a glass surface that is in contact with the molten metal (hereinafter also referred to as a bottom surface). It is said that this is caused by the different ways of entering chemical strengthening on both sides.

The warp of the float glass increases as the chemical strengthening becomes stronger. Therefore, when the surface compressive stress is made higher than ever, particularly 600 MPa or higher in order to meet the demand for high scratch resistance, the problem of warp becomes more obvious.

Patent Document 1 discloses a glass strengthening method in which the amount of ions entering the glass during chemical strengthening is adjusted by chemically strengthening after forming a SiO ₂ film on the glass surface. Patent Documents 2 and 3 disclose a method of reducing warpage after chemical strengthening by setting the surface compressive stress on the top surface side within a specific range.

Further, conventionally, in order to reduce the problem of warpage, chemical strengthening is performed after removing a surface heterogeneous layer by reducing the strengthening stress due to chemical strengthening or grinding or polishing at least one surface of glass. There is a solution.

US Patent Application Publication No. 2011/0293928 International Publication No. 2007/004634 Japanese Unexamined Patent Publication No. Sho 62-191449

However, in the method of chemically strengthening after forming the SiO ₂ film on the glass surface described in Patent Document 1, the preheating conditions for chemical strengthening are limited, and depending on the conditions, the film quality of the SiO ₂ film changes and warps. May be affected. Further, as described in Patent Documents 2 and 3, the method of setting the surface compressive stress on the top surface side in a specific range has a problem from the viewpoint of the strength of the glass.

Further, the method of grinding or polishing at least one surface of the glass before chemical strengthening has a problem from the viewpoint of improving productivity, and it is preferable to omit these grinding or polishing treatments.

Furthermore, if warping occurs to some extent after chemical strengthening, the gap between the glass and the stage becomes too large when printing the black frame of the cover glass, and the glass may not be adsorbed on the stage. When used for a cover glass with an integrated touch panel, ITO (Indium Tin Oxide) or the like may be formed in a large plate state in a later process. At that time, conveyance abnormalities such as glass coming into contact with the air knife in the chemical treatment tank or cleaning tank occur, warpage increases during ITO film formation, and the ITO film formation state at the periphery of the substrate is not appropriate. , May cause problems such as peeling off. In addition, in the case of a type in which a space exists between an LCD (Liquid Crystal Display) and a cover glass to which a touch panel is attached, if the cover glass has a certain amount of warpage, uneven brightness or Newton rings may occur.

Accordingly, an object of the present invention is to provide a method for producing a float glass that can effectively suppress warping after chemical strengthening and can omit or simplify polishing treatment before chemical strengthening. To do.

The inventors focused on the fact that the amount of warpage of the glass plate after chemical strengthening varies depending on the position in the width direction. And, when a gas containing molecules having fluorine atoms in its structure is blown onto the glass ribbon, by setting the total contact amount of fluorine atoms to be different in the width direction of the glass ribbon, It discovered that the curvature of a glass plate could be effectively reduced over the whole width direction, and completed this invention based on this knowledge.

That is, the present invention is as follows.
(1) A float glass manufacturing method including a step of supplying molten glass onto a molten metal and forming the glass into a glass ribbon,
Blowing a gas containing a molecule having a fluorine atom in its structure onto the glass ribbon;
The method for producing float glass, wherein the total contact amount of the fluorine atoms is different in the width direction of the glass ribbon.
(2) The float glass according to (1), wherein in the width direction of the glass ribbon, the minimum value of the total contact amount is a value obtained by reducing the maximum value of the total contact amount by a maximum of 100%. Manufacturing method.
(3) In the central portion in the width direction of the glass ribbon, the total contact amount is maximum,
The method for producing a float glass according to (1) or (2), wherein the total contact amount is minimum at both ends in the width direction of the glass ribbon.
(4) In the width direction of the glass ribbon, the minimum value of the total contact amount is a value reduced by 7.7 to 25% from the maximum value of the total contact amount. The manufacturing method of the float glass as described in any one of 3).
(5) The glass transition temperature of the molten glass is 550 ° C. or higher,
The method for producing a float glass according to any one of (1) to (4), wherein the temperature of the glass ribbon is 600 ° C. or higher.

In the float glass manufacturing method of the present invention, the ion contact rate in the width direction of the glass plate is adjusted by changing the total contact amount of fluorine atoms in the width direction of the glass ribbon, and chemical strengthening is entered. Can be equalized. Therefore, it is possible to reduce the warpage of the glass plate after chemical strengthening and obtain excellent flatness even if the stress due to chemical strengthening is set to a desired value and the polishing process before chemical strengthening is simplified or omitted. it can.

FIG. 1 is a diagram schematically showing a double-flow type injector that can be used in the present invention. FIG. 2 is a diagram schematically showing a single-flow injector that can be used in the present invention. FIG. 3 is a cross-sectional view of a flat panel display used as a cover glass for a flat panel display after chemically strengthening the chemically strengthened float glass of the present invention. FIG. 4A is a schematic explanatory view of a method of processing the surface of a glass ribbon by supplying a gas containing molecules having fluorine atoms in the structure thereof by a beam in the production of a glass plate by a float process. . FIG. 4B is a cross-sectional view taken along the line AA in FIG. FIGS. 5A to 5D are cross-sectional views of beams that can be adjusted by dividing the amount of gas into three in the width direction of the glass ribbon.

1. Glass plate In the present invention, the “glass plate” includes those in which molten glass is formed into a plate shape. For example, a so-called glass ribbon in a float bath is also a glass plate. The warpage after chemical strengthening of the glass plate is caused by the difference in the way of chemical strengthening on one side and the other side of the glass plate. Specifically, for example, in the case of float glass, chemical strengthening is performed on the glass surface (top surface) that is not in contact with the molten metal (usually tin) and the glass surface (bottom surface) that is in contact with the molten metal during float forming. Warping after chemical strengthening occurs due to the difference in the way of entering.

Thus, for example, by treating the glass plate with fluorine so that the difference between the fluorine concentration on one surface and the fluorine concentration on the other surface is greater than a specific range, ions on one surface and the other surface of the glass plate By adjusting the diffusion rate, it is possible to balance the entry of chemical strengthening on one side and the other side. In that case, the glass plate can reduce warpage of the glass plate after chemical strengthening without adjusting the strengthening stress or without performing processing such as grinding and polishing before the chemical strengthening treatment.

As a mechanism that can reduce the warpage after chemical strengthening by treating the surface of the glass plate with fluorine, the following phenomenon is considered to have occurred.
(1) Relaxation is promoted by fluorine taken into the surface of the glass, and CS (compressive stress) of the surface treated with fluorine is reduced.
(2) Ion exchange is inhibited by fluorine taken into the surface of the glass, and DOL (depth of layer, compression stress depth) of the surface treated with fluorine decreases.
(3) The dealkalization of the glass occurs by the fluorine treatment.
(4) The main component of the glass surface is changed by the fluorine treatment, and Si in the glass is reduced from the glass surface as SiF ₄ or H ₂ SiF ₆ , so that the stress is changed.
(5) The warp is reduced by suppressing the dehydration from the glass surface or the intrusion of water by the fluorine treatment.

2. Method for Manufacturing Glass Plate In the present invention, the following method is used for forming molten glass into a plate-shaped glass plate. First, various amounts of various materials are prepared, heated and melted, then homogenized by defoaming or stirring, formed into a plate shape by a well-known float method, slowly cooled, cut to a desired size, and then subjected to polishing. Thus, a glass plate is manufactured. Thus, the glass manufactured by the float process is preferable because the improvement of warpage after chemical strengthening, which is the effect of the present invention, is easily exhibited.

Specific examples of the glass plate used in the present invention include a glass plate typically made of soda lime silicate glass, aluminosilicate glass, borate glass, lithium aluminosilicate glass, or borosilicate glass.

Among these, glass having a composition containing Al is preferable. When Al coexists with Al, it takes 4-coordination and participates in the formation of a network that becomes a glass skeleton like Si. When tetracoordinate Al increases, movement of alkali ions becomes easy, and ion exchange easily proceeds during chemical strengthening treatment.

The thickness of the glass plate is not particularly limited, and examples thereof include 2 mm, 0.8 mm, 0.73 mm, 0.7 mm, 0.56 mm, and 0.4 mm. In order to carry out, it is usually preferably 5 mm or less, more preferably 3 mm or less, further preferably 1.5 mm or less, and particularly preferably 0.8 mm or less.

Usually, the warp amount after chemical strengthening of a 0.7 mm thick glass plate is required to be 40 μm or less. When a 90 mm square glass plate has a CS of 750 MPa and a DOL of 40 μm, the amount of warpage after chemical strengthening is about 130 μm. On the other hand, the amount of warpage of the glass plate after chemical strengthening is inversely proportional to the square of the plate thickness, so the amount of warpage when the thickness of the glass plate is 2.0 mm is about 16 μm, and the warpage is substantially a problem. Never become. Therefore, the problem of warpage after chemical strengthening may occur when the thickness of the glass plate is less than 2 mm, typically 1.5 mm or less.

The composition of the glass plate of the present invention is a composition expressed in mol%, SiO ₂ is 50 to 80%, Al ₂ O ₃ is 0.1 to 25%, Li ₂ O + Na ₂ O + K ₂ O is 3 to 30%. , A glass containing 0 to 25% MgO, 0 to 25% CaO and 0 to 5% ZrO ₂ , but is not particularly limited. Although it does not specifically limit more specifically, For example, the following glass compositions are mentioned. For example, “containing 0 to 25% of MgO” means that MgO is not essential but may contain up to 25%. The glass of (i) is contained in soda lime silicate glass, and the glass of (ii) and (iii) is contained in aluminosilicate glass.
(I) A composition expressed in mol%, with SiO ₂ being 63 to 73%, Al ₂ O ₃ being 0.1 to 5.2%, Na ₂ O being 10 to 16%, and K ₂ O being 0 to 1. Glass (ii) containing 5%, MgO 5 to 13% and CaO 4 to 10%. The composition expressed as mol% is SiO ₂ 50 to 74%, Al ₂ O ₃ 1 to 10%, Na ₂ Contains 6-14% O, 3-11% K ₂ O, 2-15% MgO, 0-6% CaO and 0-5% ZrO ₂ , and contains SiO ₂ and Al ₂ O ₃ composition total 75% or less, and displayed in the total content of Na ₂ O content and _{K 2} O 12 to 25% glass (iii) mol percent total of 7 to 15% of the content of MgO and CaO 0 but the SiO ₂ 68 ~ 80%, the _{_{Al 2 O 3 4 ~ 10%}} , a Na ₂ O 5 ~ 15%, the _{K 2} O 1%, the MgO 4 ~ 15% and ZrO ₂ are compositions displaying 0-1% glass containing (iv) mol%, a SiO ₂ 67 ~ 75%, the _{_{Al 2 O 3 0 ~ 4%}} , Na ₂ O the 7 ~ 15% _{K 2} O 1-9% of MgO 6 ~ 14% and the ZrO ₂ and contains 0 to 1.5% total content of SiO ₂ and _Al 2 _{O 3} is 71 -75%, the total content of Na ₂ O and K ₂ O is 12 to 20%, and when CaO is contained, the content is less than 1%

In the method for producing a glass plate of the present invention, at least one surface of a glass ribbon is subjected to a surface treatment by contacting a gas or liquid containing molecules having fluorine atoms in the structure (hereinafter referred to as a fluorine-containing fluid). . When the surface treatment is performed by bringing the fluorine-containing fluid into contact with at least one surface of the glass ribbon, the temperature of the glass ribbon is preferably 650 ° C. or higher. By setting it as 650 degreeC or more, it becomes easy to implement HF spraying process by HF total contact amount (after-mentioned) sufficient to reduce the curvature amount of the glass after chemical strengthening. Hereinafter, the term “glass plate” may be used as a generic term for a glass plate and a glass ribbon.

Examples of the fluorine-containing fluid include hydrogen fluoride (HF), flon (for example, chlorofluorocarbon, fluorocarbon, hydrochlorofluorocarbon, hydrofluorocarbon, and halon), hydrofluoric acid, fluorine alone, trifluoroacetic acid, and carbon tetrafluoride. , Silicon tetrafluoride, phosphorus pentafluoride, phosphorus trifluoride, boron trifluoride, nitrogen trifluoride, chlorine trifluoride and the like, but are not limited to these gases or liquids.

Among these, hydrogen fluoride, chlorofluorocarbon or hydrofluoric acid is preferable because of its high reactivity with the glass plate surface. Moreover, you may mix and use 2 or more types among these gases. Further, when the glass is produced by the float process, when the fluorine-containing fluid is sprayed on the glass ribbon, it is preferable not to use a single fluorine because the oxidizing power is too strong in the float bath.

When a liquid is used, the liquid may be supplied to the glass plate surface by spray coating, for example, or may be supplied to the glass plate surface after vaporizing the liquid. Moreover, you may dilute with another liquid or gas as needed.

The fluorine-containing fluid may contain a liquid or a gas other than those liquids or gases, and is preferably a liquid or a gas that does not react with molecules having fluorine atoms at room temperature.

Examples of the liquid or gas include, but are not limited to, N ₂ , air, H ₂ , O ₂ , Ne, Xe, CO ₂ , Ar, He, and Kr. Moreover, 2 or more types of these gases can also be mixed and used.

As a gas carrier gas containing molecules having fluorine atoms in its structure, it is preferable to use an inert gas such as N ₂ or argon. Further, the gas containing a molecule having a fluorine atom in its structure may further contain SO ₂ . SO ₂ is used when a glass plate is continuously produced by a float process or the like, and has a function of preventing wrinkles from being generated on the glass due to the conveyance roller coming into contact with the glass plate in the slow cooling region. Moreover, the gas decomposed | disassembled at high temperature may be included.

Furthermore, the fluorine-containing fluid may contain water vapor or water. Water vapor can be extracted by bubbling an inert gas such as nitrogen, helium, argon, carbon dioxide in heated water. When a large amount of water vapor is required, it is also possible to take a method in which water is sent directly to the vaporizer and vaporized directly.

In the present invention, as a specific example of a method for forming molten glass into a plate-like glass plate, for example, a float method will be described in detail. In the float process, a glass manufacturing apparatus having a melting furnace for melting glass raw materials, a float bath for floating glass on a molten metal (such as tin) to form a glass ribbon, and a slow cooling furnace for gradually cooling the glass ribbon And a glass plate (float glass) is manufactured using.

When glass is formed on a molten metal (tin) bath, a fluorine-containing fluid is supplied to the glass plate conveyed on the molten metal bath from the side not touching the metal surface (top surface). You may process the glass plate surface. In the slow cooling region following the molten metal (tin) bath, the glass plate is conveyed by roller conveyance.

Here, the slow cooling region includes not only the slow cooling furnace but also the portion from the time when the glass ribbon is unloaded from the molten metal (tin) bath to the time of being transported into the slow cooling furnace. In the slow cooling region, the gas may be supplied from the side not touching the molten metal (tin).

FIG. 4 (a) shows a schematic explanatory diagram of a method for treating a glass surface by supplying a gas containing molecules having fluorine atoms in the structure in the production of a glass plate by a float method.

In a float bath in which molten glass is floated on a molten metal (such as tin) to form a glass ribbon 101, a gas containing molecules having fluorine atoms in its structure is generated by the beam 102 inserted into the float bath. Spray onto the glass ribbon 101. As shown in FIG. 4A, the gas is preferably blown onto the glass ribbon 101 from the side where the glass ribbon 101 does not touch the molten metal surface. An arrow Ya indicates a direction in which the glass ribbon 101 flows in the float bath.

The position at which the gas is blown onto the glass ribbon 101 by the beam 102 is preferably such that the surface temperature of the glass plate is (Tg + 50 ° C.) to (Tg + 460 ° C.), where Tg is the glass transition temperature of the glass ribbon. Tg + 150 ° C.) to (Tg + 460 ° C.) is more preferable, and (Tg + 230 ° C.) to (Tg + 460 ° C.) is more preferable. Further, the position of the beam 102 may be upstream or downstream of the radiation gate 103. The amount of the gas blown onto the glass ribbon 101 is preferably 1 × 10 ⁻⁶ to 5 × 10 ⁻³ mol / glass ribbon 1 cm ² as HF.

Fig. 4 (b) shows a cross-sectional view along the line AA in Fig. 4 (a). The gas blown to the glass ribbon 101 from the Y1 direction by the beam 102 flows in from “IN” and flows out from the “OUT” direction. That is, it moves in the directions of arrows Y4 and Y5 and is exposed to the glass ribbon 101. The gas that has moved in the direction of arrow Y4 flows out from the direction of arrow Y2, and the gas that has moved in the direction of arrow Y5 flows out from the direction of arrow Y3.

Here, the amount of warpage of the glass plate after chemical strengthening may change depending on the position in the width direction of the glass ribbon 101. In such a case, it is preferable to adjust the amount of fluorine atoms contained in the gas. That is, it is preferable that the total contact amount of fluorine atoms contained in the gas is different by configuring the glass ribbon 101 so that the fluorine concentrations in the gas are different in the width direction. More specifically, in the width direction of the glass ribbon 101, the fluorine concentration of the gas is increased at a position corresponding to a position where the amount of warpage of the glass plate after chemical strengthening is large, and at a position corresponding to a position where the amount of warpage is small. It is preferable to reduce the fluorine concentration of the gas. Here, the “total contact amount” is the contact amount per unit area on the surface of the glass ribbon 101, and the unit is represented by (mol / cm ² ).

Thus, when the amount of warp of the glass plate after chemical strengthening changes depending on the position in the width direction of the glass ribbon 101, the structure of the beam 102 can be adjusted to the amount of gas in the width direction of the glass ribbon 101. By doing so, the amount of warpage may be adjusted in the width direction of the glass ribbon 101.

As a specific example, FIG. 5A shows a cross-sectional view of a beam 102 in which the amount of the gas is adjusted by dividing it into I to III in the width direction 110 of the glass ribbon 101. The gas systems 111 to 113 are divided by

partition walls

114 and 115, and the gas is caused to flow out from the gas blowing holes 116 and blown onto the glass ribbon 101.

The arrows in FIG. 5 (a) indicate the gas flow. The arrows in FIG. 5B indicate the gas flow in the gas system 111. The arrows in FIG. 5C indicate the gas flow in the gas system 112. The arrows in FIG. 5D indicate the gas flow in the gas system 113.

At this time, the gas flowing out from the

gas systems

111 and 113 is blown to both ends in the width direction of the glass ribbon 101, and the gas flowing out from the gas system 112 is sprayed to the center portion in the width direction of the glass ribbon 101. Since the fluorine concentration of the gas flowing out from the gas systems 111 to 113 is adjusted to a desired value, the total contact amount of fluorine atoms contained in the gas is different in the width direction of the glass ribbon 101. Become.

In order to change the total contact amount of fluorine atoms in the width direction of the glass ribbon 101, the fluorine concentration of the gas may be changed in the width direction of the glass ribbon 101 as described above. Not limited. For example, it is good also as a structure which changes the total contact amount of the gas containing the molecule | numerator in which a fluorine atom exists in the same density | concentration in the width direction of the glass ribbon 101, respectively.

Moreover, in the specific example mentioned above, in the width direction of the glass ribbon 101, it is configured to be divided into three locations of the central portion and both end portions so that the total contact amount of fluorine atoms is different. You may divide | segment and may comprise so that the total contact amount of a fluorine atom may differ. In this case, it is possible to reduce the warp of the glass plate after chemical strengthening more effectively.

Examples of the method for supplying the fluorine-containing fluid to the glass surface include a method using an injector (see FIGS. 1 and 2), a method using an introduction tube, and the like in addition to the method using the beam 102 described above.

1 and 2 are schematic views of an injector 10 that can be used for surface treatment of a glass plate in the present invention. FIG. 1 is a diagram schematically showing a double-flow injector 10 that can be used in the present invention. FIG. 2 is a diagram schematically showing a single-flow injector 10 that can be used in the present invention.

The fluorine-containing fluid is discharged from the central slit 1 and the outer slit 2 toward the glass plate 20, flows on the glass plate 20 through the flow path 4, and is exhausted from the exhaust slit 5. In addition, the code | symbol 21 in FIG.1 and FIG.2 is a direction through which the glass plate 20 flows, and is parallel to the flow path 4. FIG.

When the fluorine-containing fluid supplied from the injector 10 is a gas, the distance between the gas discharge port of the injector 10 and the glass plate 20 is preferably 50 mm or less.

By setting the distance to 50 mm or less, it is possible to suppress the gas from diffusing into the atmosphere, and to reach a sufficient amount of gas to the glass plate 20 with respect to the desired gas amount. On the other hand, if the distance from the glass plate 20 is too short, the glass plate 20 may be brought into contact with the injector due to fluctuations in the glass plate 20 when, for example, a glass plate produced by the float process is processed online.

When the fluorine-containing fluid supplied from the injector 10 is a liquid, there is no particular limitation on the distance between the liquid discharge port of the injector 10 and the glass plate 20, and the glass plate 20 can be disposed uniformly. That's fine.

This double-flow injector is common and is also known for use in producing low reflection glass. For example, asahi glass soda lime silicate glass (glass transition point 560 ° C.) having a thickness of 1.8 mm reheated to 600 ° C., HF gas from the central slit 1 is 1.12 SLM (liters per minute as standard gas) And nitrogen (N2) gas 9SLM may be used by heating the gas to 150 ° C. and blowing 45.5 SLM from the outer slit 2 at a flow rate of 64 cm / s. The surface roughness (arithmetic mean roughness) Ra of the glass surface sprayed with HF gas in this manner is 30.6 nm, and the value of x described above is 2.5 μm.

The injector 10 may be used in any manner such as double flow or single flow, and two or more injectors 10 may be arranged in series in the flow direction 21 of the glass plate 20 to treat the surface of the glass plate 20. As shown in FIG. 1, the double-flow injector is an injector 10 in which the flow of gas from discharge to exhaust is equally divided in the forward direction and the reverse direction with respect to the moving direction of the glass plate.

As shown in FIG. 2, the single-flow injector is an injector 10 in which the gas flow from discharge to exhaust is fixed in either the forward direction or the reverse direction with respect to the moving direction of the glass plate. When a single-flow injector is used, it is preferable that the gas flow on the glass plate 20 and the flow direction 21 of the glass plate 20 are the same in terms of airflow stability.

In addition, a fluorine-containing fluid supply port, a gas generated by reacting with the unreacted fluorine-containing fluid and the glass plate 20, or a gas exhaust port generated by reacting two or more gases of the fluorine-containing fluid Is preferably present on the same side surface of the glass plate 20.

When surface treatment is performed by supplying a fluorine-containing fluid to the surface of the glass plate 20 being conveyed, for example, when the glass plate 20 is flowing on the conveyor, the surface is supplied from the side not touching the conveyor. May be. Moreover, you may supply from the side which has touched the conveyor by using the mesh raw material which is not covered with glass belts, such as a mesh belt, for a conveyor belt.

Further, by arranging two or more conveyors in series and installing the injector 10 between adjacent conveyors, the surface of the glass plate 20 may be processed by supplying the gas from the side touching the conveyor. Moreover, when the glass plate 20 is flowing on the roller, it may be supplied from the side not touching the roller, or may be supplied from between adjacent rollers on the side touching the roller.

The same or different gas may be supplied from both sides of the glass plate 20. For example, the glass plate 20 may be surface-treated by supplying gas from both the side not touching the roller and the side touching the roller. For example, when supplying gas from both sides in the slow cooling region, the injector 10 is disposed so as to face the glass plate 20 that is continuously conveyed, and the glass plate 20 is sandwiched, and the roller is touched. Gas may be supplied from both the non-contact side and the side in contact with the roller.

The injector 10 disposed on the side in contact with the roller and the injector 10 disposed on the side not in contact with the roller may be disposed at different positions in the flow direction of the glass plate 20. In arranging at different positions, any of them may be arranged upstream or downstream with respect to the flow direction of the glass plate 20.

Further, by arranging two or more injectors 10 in the width direction of the glass plate 20 and changing the supply amount of gas supplied from each injector 10 toward the glass plate 20 and the concentration of fluorine atoms, the glass plate 20 is changed. In the width direction, the total contact amount of fluorine atoms may be set differently.

It is well known that a glass plate with a functional film is manufactured online by combining glass manufacturing technology using a float process and CVD technology. In this case, it is known that the transparent conductive film and the underlying film are formed on the glass plate by supplying gas from the surface not touching the tin or the surface not touching the roller. Yes.

For example, in the production of a glass plate with a functional film by online CVD, an injector may be disposed on the surface in contact with the roller, and a fluorine-containing fluid may be supplied from the injector to the glass plate to treat the glass plate surface. .

In the present invention, the temperature of the glass plate when the fluorine-containing fluid is supplied to the surface of the glass plate being transported and the surface is treated is such that the glass transition temperature of the glass plate is Tg. The surface temperature is preferably (Tg + 50 ° C.) to (Tg + 460 ° C.), more preferably (Tg + 150 ° C.) to (Tg + 460 ° C.), and further preferably (Tg + 230 ° C.) to (Tg + 460 ° C.).
In the molding in the float bath, the temperature is usually higher on the upstream side in the direction in which the glass ribbon flows. The diffusion of fluorine in the glass is more active as the temperature is higher, that is, as the viscosity is lower. Therefore, the fluorine treatment in the float bath is effective when performed upstream in order to increase the penetration depth of fluorine. Or the same effect can be acquired also by raising the temperature of the glass ribbon of a process position.
However, when processing is performed on the upstream side, the glass ribbon may be thinned in the float bath after the processing. In that case, since the fluorine infiltration layer also becomes thin with the glass ribbon, the depth of the fluorine infiltration layer of the finally obtained glass plate is smaller than the depth of the fluorine infiltration layer of the glass plate that has been processed the same downstream. May also become shallower. Therefore, when the fluorine treatment is performed in the float bath, it is not always effective to provide the treatment position significantly upstream in order to increase the fluorine penetration depth.
Further, in the molding process in the float bath, a device such as a top roll is installed, and the installation of the processing device may affect the molding of the glass ribbon.
Since the viscosity of the glass ribbon is an important factor, the above-mentioned viscosity range is appropriate for achieving both an effective fluorine infiltration effect by the fluorine treatment.

In addition, when introducing a predetermined amount of fluorine to a deep position of the glass, as described above, it can be achieved by spraying a higher concentration and / or a larger amount of fluorine-containing fluid at a higher temperature. Fluorine reacting with the glass raw material increases, foreign matters increase, and defects are formed in the glass.
On the other hand, the defects can be reduced by spraying the fluorine-containing fluid at a low temperature, but at a low temperature, the fluorine cannot be introduced to a deep position of the glass.
Thus, it can be said that there is a trade-off between the fluorine introduction depth and the occurrence of defects depending on the temperature at which the fluorine-containing fluid is sprayed.
Therefore, it is possible to obtain a glass having a deep fluorine introduction depth, that is, a large amount of fluorine introduction and few defects, by spraying a corresponding amount of fluorine-containing fluid in two or more temperature ranges. To preferred.

The pressure on the glass plate surface when supplying the fluorine-containing fluid to the glass plate surface is preferably an atmosphere in the pressure range of atmospheric pressure−100 Pascal to atmospheric pressure + 100 Pascal, and atmospheric pressure−50 Pascal to atmospheric pressure. More preferably, the atmosphere has a pressure range of +50 Pascals.

Regarding the gas flow rate, the case where HF is used as the fluorine-containing fluid will be described as an example. When processing a glass plate with HF, the higher the HF flow rate, the greater the warp improvement effect during the chemical strengthening treatment, which is preferable. When the total gas flow rate is the same, the higher the HF concentration, the better the warp improvement effect during the chemical strengthening treatment. Becomes larger.

When both the total gas flow rate and the HF gas flow rate are the same, the longer the time for processing the glass plate, the greater the warp improving effect during the chemical strengthening process. For example, when the glass plate surface is treated with a fluorine-containing fluid after the glass plate is heated, the warpage after chemical strengthening is improved as the conveyance speed of the glass plate is lower. Even in facilities where the total gas flow rate and HF flow rate cannot be controlled well, the warpage after chemical strengthening can be improved by appropriately controlling the conveying speed of the glass plate.

3. Chemical strengthening Chemical strengthening is performed by ion exchange at a temperature below the glass transition point to convert an alkali metal ion (typically Li ion or Na ion) having a small ion radius on the glass surface to an alkali metal ion having a larger ion radius. This is a process of forming a compressive stress layer on the glass surface by exchanging with (typically K ions). The chemical strengthening treatment can be performed by a conventionally known method.

The glass plate of the present invention is a glass plate with improved or improved warpage after chemical strengthening. The amount of warpage (warpage variation) of the glass plate after chemical strengthening relative to the glass plate before chemical strengthening is measured by a three-dimensional shape measuring machine (for example, manufactured by Mitaka Kogyo Co., Ltd.), or surface roughness and contour shape measurement It can be measured with a machine (for example, manufactured by Tokyo Seimitsu Co., Ltd.).

In the present invention, the improvement of the warp in the width direction after chemical strengthening is based on the following formula in the experiment under the same conditions except that the surface treatment is performed with a gas or liquid containing a molecule having a fluorine atom in the structure. Evaluation is based on the required Δ improvement rate.

Δ improvement rate (%) = [1− (ΔY / ΔX)] × 100
ΔX: difference between the maximum value and the minimum value in the width direction of the warped amount after strengthening of the untreated glass plate ΔY: difference between the maximum value and the minimum value in the width direction of the warped amount after strengthening of the treated glass plate

The CS (surface compression stress) and DOL (compression stress layer depth) of the glass plate can be measured by a surface stress meter {for example, a surface stress meter (FSM-6000LE} manufactured by Orihara Seisakusho Co., Ltd.) The surface compressive stress is preferably 600 MPa or more, and the depth of the compressive stress layer is preferably 15 μm or more, and by making the surface compressive stress of the chemically strengthened glass and the depth of the compressive stress layer within this range, excellent High strength and scratch resistance can be obtained.

4). Flat panel display device Hereinafter, after chemically strengthening the glass plate of the present invention, an example in which the chemically strengthened glass is used as a cover glass of the flat panel display device will be described. FIG. 3 is a cross-sectional view of a display device in which a cover glass is disposed. In the following description, front, rear, left and right are based on the direction of the arrow in the figure.

As shown in FIG. 3, the display device 40 includes a display panel 45 provided in the housing 15 and a cover glass 30 that covers the entire surface of the display panel 45 and surrounds the front of the housing 15.

The cover glass 30 is installed mainly for the purpose of improving the aesthetics and strength of the display device 40, preventing impact damage, and the like, and the overall shape is formed from a single plate-like glass having a substantially planar shape. As shown in FIG. 3, the cover glass 30 may be installed so as to be separated from the display side (front side) of the display panel 45 (having an air layer), and has a translucent adhesive film (FIG. (Not shown) may be attached to the display side of the display panel 45.

A functional film 41 is provided on the front surface of the cover glass 30 that emits light from the display panel 45, and a functional film 42 is provided on the rear surface on which the light from the display panel 45 is incident at a position corresponding to the display panel 45. ing. In addition, although the

functional films

41 and 42 are provided on both surfaces in FIG. 3, the

functional films

41 and 42 are not limited to this and may be provided on the front surface or the back surface, or may be omitted.

The

functional films

41 and 42 have functions such as anti-reflection of ambient light, prevention of impact breakage, electromagnetic wave shielding, near-infrared shielding, color tone correction, and / or scratch resistance improvement, and thickness and shape are used for applications. It is selected as appropriate. The

functional films

41 and 42 are formed, for example, by attaching a resin film to the cover glass 30. Or you may form by thin film formation methods, such as a vapor deposition method, a sputtering method, or CVD method.

Reference numeral 44 denotes a black layer, which is, for example, a coating formed by applying ink containing pigment particles to the cover glass 30, irradiating it with ultraviolet rays, or heating and baking it, and then cooling it. The display panel and the like cannot be seen from the outside, and the appearance is improved.

Thus, when the glass plate of the present invention is used as a cover glass for a display device, the surface roughness (arithmetic average roughness) Ra is preferably 2.5 nm or less, and more preferably 1.5 nm or less. . Thereby, it can prevent impairing the clearness of the display image of a display apparatus with a cover glass. The surface roughness Ra of the glass plate can be measured as follows based on JIS B0601 (2001). Using an AFM (Atomic Force Microscope), for example, Park Systems, XE-HDM as a measuring device, measure 3 locations at a scan size of 1 μm × 1 μm, and average the 3 locations. Ra value.

Examples of the present invention will be specifically described below, but the present invention is not limited to these.

(Composition of glass plate)
In this example, a glass plate of glass material A having the following composition was used.
(Glass A) In terms of mol%, SiO ₂ is 64.3%, Al ₂ O ₃ is 8.0%, Na ₂ O is 12.5%, K ₂ O is 4.0%, and MgO is 10.5. %, CaO 0.1%, SrO 0.1%, BaO 0.1% and ZrO ₂ 0.5% (glass transition temperature 604 ° C.)

(Measurement of warpage)
The amount of warpage after chemical strengthening was measured with a Surfcom surface roughness / contour shape measuring machine (manufactured by Tokyo Seimitsu Co., Ltd.).

(Δ improvement rate)
The improvement in warpage in the width direction after chemical strengthening was evaluated by the Δ improvement rate obtained by the following formula in all the experiments under the same conditions except that the surface treatment was performed with a fluorine-containing fluid.

(CS and DOL)
CS and DOL were measured using a surface stress meter (FSM-6000LE) manufactured by Orihara Seisakusho.

As shown in FIG. 4A, in the float bath in which the glass ribbon 101 of the glass material A described above flows, HF is added to the glass ribbon 101 in Table 1 by the beam 102 inserted at a position where the glass ribbon 101 is about 800 ° C. Sprayed under the conditions shown. The temperature of the glass ribbon when HF is sprayed is 770 to 800 ° C. in all comparative examples and examples.

In Examples 1-1 to 1-2, 2-1 to 2-4, 3-1, and 4-1, as shown in Table 1, the HF molar concentration of the process gas sprayed in the width direction of the glass ribbon 101 The total contact amount of fluorine atoms was changed so that the total contact amount of fluorine atoms was different. More specifically, when the center position in the width direction of the glass ribbon 101 is the origin, the right side in the flow direction Ya of the glass ribbon 101 is the + direction, and the left side is the − direction, −2320 to −1473 mm (FIG. 4 ( a) in the vicinity of position X3 in FIG. 4A), −1473 to +1473 mm (in the vicinity of position X2 in FIG. 4A), and +1473 to +2320 mm in the vicinity of position X1 in FIG. 4A. Changed. In particular, the HF total contact amount is set to the minimum value in the vicinity of positions X1 and X3 (both ends in the width direction), and the HF contact amount is set to the maximum value in the vicinity of position X2 (width direction center). Here, the minimum value of the HF total contact amount is a value obtained by reducing the maximum value of the HF total contact amount by 7.7 to 100%.

In Comparative Examples 1-1, 2-1, 3-1, and 4-1, HF was not sprayed on the glass ribbon 101. In Comparative Examples 1-2, 2-2, 3-2, and 4-2, In the width direction of the glass ribbon 101, the HF molar concentration of the process gas to be sprayed was set to be equal so that the total contact amount of HF was equal.

Further, regarding the glasses at Comparative Example 1-1, 2-1, 3-1, 4-1, 4-2 and Example 3-1, 4-1 in the width direction position -318 mm, the surface stresses on the front and back surfaces (Hereinafter referred to as CS) and stress layer depth (hereinafter referred to as DOL) were measured. The average value is also shown in Table 1. In Comparative Example 1-2 and Examples 1-1 to 1-2, the chemical strengthening time and the temperature of the chemical strengthening salt are the same as in Comparative Example 1-1. Further, Comparative Example 2-2 and Examples 2-1 to 2-4 have the same chemical strengthening time and chemical strengthening salt temperature as Comparative Example 2-1. In Comparative Examples 3-1, 3-2 and Example 3-1, the chemical strengthening time and the temperature of the chemical strengthening salt are all the same. Further, all of Comparative Examples 4-1 and 4-2 and Example 4-1 have the same chemical strengthening time and chemical strengthening salt temperature.

The glasses of Comparative Examples and Examples obtained at a position of 15 points in the width direction shown in Table 2, was cut into 100mm square, the glass was immersed in the heated KNO ₃ molten salt, it was chemically strengthened . Next, a value corresponding to the warp of the 90 mm square portion of the substrate was measured twice, and the average value was taken as the warp amount after reinforcement.

The amount of warp after strengthening at a predetermined position in the width direction of the glass ribbon 101, the average value of these warp amounts after strengthening, Δ which is the difference between the maximum value and the minimum value in the width direction of the warp amount after strengthening, and Comparative Example 1-1, Table 2 shows the Δ improvement rate, which is the reduction ratio of Δ with respect to Δ of 2-1, 3-1, 4-1.

Referring to Comparative Examples 1-1, 2-1, 3-1 and 4-1 in Table 2, it can be seen that the amount of warp after strengthening differs depending on the position of the glass ribbon 101 in the width direction when HF is not sprayed. In particular, in Comparative Examples 1-1, 2-1, and 3-1, the amount of warp after strengthening increases toward the center in the width direction of the glass ribbon 101, and the amount of warp after strengthening decreases toward the both ends in the width direction. The tendency to become is remarkable.

On the other hand, in Comparative Examples 1-2, 2-2, 3-2 and 4-2 in which the HF total contact amount (total contact amount of fluorine atoms) is set equal in the width direction of the glass ribbon 101, Comparative Example 1 Compared with −1, 2-1, 3-1, and 4-1, the warped amount after strengthening is reduced in the entire width direction, and the average value of warpage, Δ, and Δ improvement rate are improved. This is due to the fact that the warp after chemical strengthening was reduced by the fluorine treatment of the surface of the glass ribbon. However, the tendency that the warpage amount at the center in the width direction of the glass ribbon 101 is large and the warpage amount at both ends in the width direction is small is the same as in Comparative Examples 1-1, 2-1, and 3-1, and further flatness is increased. Improvement is desired.

Further, in Examples 1-1 to 1-2, 2-1 to 2-4, 3-1, and 4-1, in which the HF total contact amount (total contact amount of fluorine atoms) in the width direction of the glass ribbon 101 was changed Compared with Comparative Examples 1-1, 2-1, 3-1, and 4-1, the warped amount after strengthening is reduced over the entire width direction, and the average value of warpage, Δ, and Δ improvement rate are improved. Yes. In particular, in Examples 1-1 to 1-2, 2-1, 3-1, 4-1, that is, in the width direction of the glass ribbon 101, the minimum value of the HF total contact amount is the HF total contact amount. In the case where the value is reduced by 7.7 to 25% from the maximum value, the Δ and Δ improvement rates are improved as compared with Comparative Examples 1-2 and 2-2, and over the entire width direction. It can be seen that a more uniform warp distribution is obtained.

In this way, by setting the HF total contact amount to be different in the width direction of the glass ribbon 101, more specifically, the HF total contact amount is increased at a position where the post-strengthening warpage amount is large (the central portion in the width direction). And it became clear that the amount of warpage after reinforcement can be effectively reduced over the entire width direction by reducing the total contact amount of HF at the position where the amount of warpage after reinforcement is small (both ends in the width direction).

Thus, generally, the amount of warpage of the glass sheet after chemical strengthening tends to increase toward the center in the width direction and decreases toward both ends in the width direction. It is preferable to adjust the contact amount. However, unlike the glass ribbon 101 described above, for example, when the warped amount after strengthening decreases toward the center in the width direction and the warped amount after strengthening increases toward both ends in the width direction, the width direction By reducing the total HF contact amount at the center and decreasing the HF total contact amount at both ends in the width direction, the same effect can be obtained.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention.

This application is based on Japanese Patent Application No. 2013-198476 filed on Sep. 25, 2013, the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 Central slit 2 Outer slit 4 Flow path 5 Exhaust slit 15 Housing | casing 20 Glass plate 30 Cover glass 40

Display apparatus

41, 42 Functional film 45 Display panel 101 Glass ribbon 102 Beam 103 Radiation gate 110 Glass ribbon width direction 111,112, 113

Gas system

114, 115 Partition 116 Gas blow hole

Claims

A float glass manufacturing method comprising a step of supplying molten glass onto a molten metal and forming a glass ribbon,
Blowing a gas containing a molecule having a fluorine atom in its structure onto the glass ribbon;
The method for producing float glass, wherein the total contact amount of the fluorine atoms is different in the width direction of the glass ribbon.
2. The method of manufacturing float glass according to claim 1, wherein in the width direction of the glass ribbon, the minimum value of the total contact amount is a value obtained by reducing the maximum value of the total contact amount by a maximum of 100%. .
In the central portion in the width direction of the glass ribbon, the total contact amount is maximum,
The method for producing a float glass according to claim 1 or 2, wherein the total contact amount is minimum at both ends in the width direction of the glass ribbon.
4. The minimum value of the total contact amount in the width direction of the glass ribbon is a value obtained by reducing the maximum value of the total contact amount by 7.7 to 25%. The manufacturing method of the float glass of 1 item | term.
The glass transition temperature of the molten glass is 550 ° C. or higher,
The method for producing a float glass according to any one of claims 1 to 4, wherein the temperature of the glass ribbon is 600 ° C or higher.