WO2014024641A1

WO2014024641A1 - Thin sheet glass manufacturing method

Info

Publication number: WO2014024641A1
Application number: PCT/JP2013/069180
Authority: WO
Inventors: 匡博津田; 白石　喜裕
Original assignee: 旭硝子株式会社
Priority date: 2012-08-09
Filing date: 2013-07-12
Publication date: 2014-02-13
Also published as: TW201410621A; JP2015187041A

Abstract

Provided is a thin sheet glass manufacturing method that has: a melting step for melting a glass raw material into a molten glass; a forming step for forming the molten glass into a glass ribbon; a transfer step for transferring the glass ribbon using transfer rollers; and a width-direction cutting step for cutting the glass ribbon in the width direction. When starting manufacture, at least a transfer-direction leading end portion of the glass ribbon is formed, in the forming step, with a thickness with which the glass ribbon can pass on the transfer rollers in the transfer step, and after the transfer-direction leading end portion of the glass ribbon is subjected to the width-direction cutting step, the thickness of the glass ribbon formed in the forming step is changed to a product thickness.

Description

Thin glass manufacturing method

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

As a method for producing plate glass, a glass ribbon formed of molten glass in a sheet shape is cooled by transporting the inside of a slow cooling furnace with a transport roller, and then a belt-shaped glass ribbon continuously transported from the slow cooling furnace has a predetermined size by a cutting device. A method of cutting into a rectangular glass plate is known (for example, Patent Document 1).

Thus, in the plate glass manufacturing process, a method is used in which a glass ribbon is transported by a transport roller in a slow cooling furnace and in a cutting device.

In the slow cooling furnace, the glass ribbon is generally heated from the upper and lower surfaces, and from the viewpoint of securing a heat transfer path to the glass ribbon, there is a case where the slow cooling is performed while supplying the gas. From the viewpoint of securing the supply path, a transport roller that can be arranged at an interval is used.

In the cutting device, if glass fragments, cutting debris, etc. generated during cutting, etc. remain on the transport path, there is a risk of scratching the surface of the subsequent glass ribbon. A conveyance roller is used so that it can be easily removed.

Also, in any process, the transport roller is widely used because it has little influence on the glass quality and can be handled regardless of the plate thickness, glass composition, and the like.

International Publication No. 2010/007953

By the way, in recent years, especially for display applications, a thin plate glass has been demanded. Even in the case of manufacturing a thin plate glass, a transport roller is used for transporting the glass ribbon in the slow cooling furnace, the cutting device, or the like for the reasons described above.

However, for example, as shown in FIG. 1, when the front end of the glass ribbon 11 is flown on the transport path as a target product thickness at the start of manufacture, the front end portion 11 a of the glass ribbon 11 bends, and the transport roller 12. There was a problem that the glass ribbon could not pass over.

Thus, if the tip of the glass ribbon does not reach the end of the manufacturing process, a thin glass cannot be produced. For this reason, a plate glass having a thickness that may not be able to pass over the transport roller cannot be stably produced, which causes a problem in manufacturing a thin plate glass that is particularly easily bent.

It is effective to reduce the roller pitch in order to ensure that the tip of the glass ribbon can pass through the transport roller. Therefore, it is conceivable to adjust the interval between the conveying rollers, but the interval 13 between the conveying rollers 12 needs to be arranged so that at least adjacent conveying rollers do not contact each other. For this reason, since it is restricted by the diameter of the transport roller 12, there is a limit in reducing the distance. The roller pitch is the distance between the centers of adjacent rollers, that is, the sum of the diameter of the transport roller 12 and the interval 13 between the transport rollers 12 in FIG.

Further, it is necessary to determine the diameter of the conveyance roller 12 so that the conveyance roller 12 does not bend itself, and the diameter is restricted by the width of the glass ribbon (the length of the glass ribbon perpendicular to the conveyance direction) and the like. .

For this reason, the roller pitch cannot be shortened sufficiently only by adjusting the spacing of the transport rollers, etc., and the problem that the glass ribbon may not pass on the transport rollers cannot be solved. There was a need for a solution.

In the present invention, in view of the problems of the above-described conventional technology, the front end of the glass ribbon in the conveyance direction can pass through the conveyance roller more reliably at the start of production of the thin glass, and the thin plate can improve yield and productivity. It aims at providing the manufacturing method of glass.

In order to solve the above problems, the present invention
A melting step of melting a glass raw material into a molten glass;
A molding process for forming molten glass into a glass ribbon;
A conveying step of conveying the glass ribbon by a conveying roller;
A width direction cutting step of cutting the glass ribbon in the width direction,
At the start of production, the thickness of at least the leading end of the glass ribbon in the forming step is set to a thickness that can pass through the transfer roller in the transfer step,
Provided is a thin glass manufacturing method in which the thickness of the glass ribbon formed in the forming step is changed to a thickness for a product after the front end of the glass ribbon in the conveying direction passes through the width direction cutting step.

According to the method for producing a thin glass of the present invention, the glass ribbon can pass more reliably on the transport roller at the start of production of the thin glass (when the production apparatus is started up). For this reason, the yield improvement and productivity improvement of thin glass can be aimed at.

It is explanatory drawing of the behavior of the glass ribbon on the conveyance roller in a prior art. It is the schematic of the manufacturing process at the time of using a float process as a shaping | molding process in embodiment of this invention. It is explanatory drawing of plate | board thickness control by the float method in embodiment of this invention. It is the schematic of the manufacturing process at the time of using the fusion method as a shaping | molding process in embodiment of this invention. It is explanatory drawing of the behavior of the glass ribbon on the conveyance roller in embodiment of this invention. It is explanatory drawing of the plate | board thickness distribution of the width direction of the glass ribbon by the shaping | molding method in embodiment of this invention. It is explanatory drawing of the cutting process in embodiment of this invention. It is explanatory drawing of the cutting process in embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.

Hereinafter, a method for producing the thin glass of the present embodiment will be described.

According to one aspect of the present invention, a method for producing a thin glass of the present invention includes a melting step of melting a glass raw material to form molten glass, a molding step of forming molten glass to form a glass ribbon, and the glass ribbon. It has the conveyance process conveyed with a conveyance roller, and the width direction cutting process which cut | disconnects a glass ribbon in the width direction (direction perpendicular | vertical to the conveyance direction of a glass ribbon).

Then, at the start of production, in the molding step, at least the thickness of the tip of the glass ribbon in the transport direction is set to a thickness that can pass through the transport roller in the transport step, and the tip of the glass ribbon in the transport direction is the width. After passing through the direction cutting step, the thickness of the glass ribbon formed in the forming step is changed to a product thickness.

First, each process will be described below.

The melting step is a step of melting glass raw material to form molten glass.

The glass raw material used here is not particularly limited, and the glass raw material can be mixed and used at a predetermined ratio so as to have a target composition (glass type) corresponding to the performance required for the product.

Also, the melting temperature can be selected based on the glass raw material used and its composition.

Here, the type of glass to which the manufacturing method of the present embodiment is applied is not particularly limited, and can be used for manufacturing soda-lime glass, alkali-free glass, and the like. Since thin glass sheets with a particularly small thickness are required for display applications, they can be used particularly suitably for the production of alkali-free glass.

The molten glass obtained in the melting step is preferably subjected to defoaming treatment (clarification treatment) before being subjected to the molding step.

The defoaming process is a step of removing bubbles contained in the molten glass, and bubbles contained in the thin glass of the final product can be reduced by performing such steps. For this reason, it is preferable to perform such treatment in applications where bubbles in the glass are problematic, such as for display applications.

The defoaming method is not particularly limited. For example, a method of adding a clarifier to the molten glass, a method of defoaming by holding the molten glass at a high temperature, or a molten glass A method of defoaming in a reduced-pressure atmosphere is mentioned.

Next, the molding process will be described.

The forming step is a step of forming molten glass into a glass ribbon, and the specific means thereof is not limited, but can be selected according to the specifications required for the thin glass of the final product. . In particular, with respect to the float process and the fusion process, a glass ribbon (plate glass) with high flatness can be obtained, and therefore it is preferable to perform the forming step by any method. Other downdraw methods (redraw method and slot downdraw method) can also be selected.

Above all, the float method is more preferably used as a molding method in the molding process because a wide glass ribbon can be stably produced and productivity can be improved.

The specifications of the glass ribbon to be formed in the forming process can be selected in consideration of the specifications of the thin glass to be manufactured and the productivity. However, since it becomes possible to increase productivity especially when the width of the glass ribbon is wide, the width of the glass ribbon for products is preferably 1.5 m or more, more preferably 2.5 m or more. preferable. Here, the glass ribbon for products means a glass ribbon after the thickness of the glass ribbon is changed to the thickness for products as will be described later. It does not specifically limit about the upper limit of the width | variety of a glass ribbon, It can select according to the upper limit of manufacturing equipment.

In addition, since it is preferable that the width of the glass ribbon at the start of production is the same as or approximately the same as the width of the glass ribbon for products, the width of the glass ribbon at the start of manufacture is also 1.5 m or more. Preferably, it is 2.5 m or more.

Although the thickness of the glass ribbon is not limited, the thin glass manufacturing method of the present embodiment transports the glass ribbon by the transport roller at the start of manufacture due to the bending of the tip in the transport direction of the glass ribbon. It is intended to suppress the phenomenon that the roller cannot pass.

This is because, in particular, when the target product portion is thin, when it is molded to such a thickness from the start of manufacture, it cannot pass through the transport roller, whereas in the manufacturing method of this embodiment, it is reliably transported. It will be able to pass through the roller and will exert its effect. For this reason, it is the thickness for the product of the glass ribbon shape | molded by the said formation process among the plate | board thickness of the glass ribbon, Comprising: It is preferable that the plate | board thickness of the width direction center part of a glass ribbon is 0.2 mm or less. . In particular, it is more preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

The plate thickness of the product section here refers to the product portion after the glass ribbon conveyance direction tip has passed the width direction cutting step and the glass ribbon plate thickness is changed to the product thickness as will be described later. It means the thickness of the glass ribbon (the central portion in the width direction that is finally cut out as a product). The lower limit of the thickness of the glass ribbon in the width direction center (product part) is not particularly limited, but the conveyance speed is such that the glass ribbon does not break during conveyance from the forming step to the width direction cutting step. It is preferable to select according to the type and characteristics of the glass. For example, the lower limit value of the thickness of the central portion in the width direction of the glass ribbon is preferably 0.01 mm or more, more preferably 0.02 mm or more, and particularly preferably 0.03 mm or more, based on stable production conditions based on the glass forming principle. preferable.

A conveyance process is a process of conveying the glass ribbon shape | molded in the shaping | molding process with a conveyance roller, and includes conveyance in a slow cooling process, the width direction cutting process, and also the both-ends part cutting process depending on the case. Since the conveyance step includes a slow cooling step, the glass ribbon can be gradually cooled and cooled while being conveyed to the width direction cutting step (width direction cutting device). For this reason, in a conveyance process, in order to cool and cool a glass ribbon to predetermined temperature, the surrounding temperature etc. can also be controlled by providing a slow cooling furnace.

There are no particular limitations on the diameter, length, and roller pitch of the transport rollers used in the transport process. The diameter and length of the conveying roller can be determined by the thickness and width of the thin glass to be produced, that is, the size of the glass ribbon. The roller pitch can be determined by the diameter of the transport roller.

The number of transport rollers can be selected according to the length of the transport process, the time required for the transport process, and the like, and is not limited.

However, in the production of thin glass, as the glass ribbon having a wider width can improve productivity as described above, it is preferable that the length of the transport roller is also a length corresponding to this. And when the length of a conveyance roller becomes long, it is preferable to have a diameter (thickness) according to it so that a conveyance roller itself may not bend, and the roller so that conveyance rollers may not contact at least according to this The pitch will be selected.

In this embodiment, even if the roller pitch is increased as will be described later, it is possible to suppress the possibility that the tip of the glass ribbon cannot pass through the transport roller at the start of manufacture. It may be wide. Specifically, for example, the roller pitch between the transport rollers is preferably 200 mm or more, more preferably 300 mm or more, and particularly preferably 400 mm or more. At this time, the upper limit value is not limited and can be selected depending on the diameter of the transport roller. When a slow cooling furnace is provided or a gas is circulated in the conveying step, it is preferable to increase the roller pitch because heat can be easily transmitted and gas can be easily diffused.

Note that, as described above, the roller pitch means the distance between the centers of adjacent transport rollers, and thus is the sum of the diameter of the transport rollers and the distance between the transport rollers. For example, referring to FIG. 1, the conveyance roller radius R × 2 + conveyance roller interval 13 is the roller pitch L.

The width direction cutting step is a step of cutting the glass ribbon that has been conveyed by the conveyance roller in the conveyance step in the width direction (a direction perpendicular to the conveyance direction of the glass ribbon).

The width direction cutting step only needs to cut the glass ribbon in the width direction, and is limited only to the case where the glass ribbon is accurately cut into a desired size by a predetermined width direction cutting device in order to obtain a product. is not.

For example, in order to discard the tip of the glass ribbon at the start of production, etc., the downstream end of the transport roller is opened (without being connected to the width direction cutting device for product cutting). The case where the protruding glass ribbon is cut (broken) in the width direction by its own weight is also included in the width direction cutting step here.

Further, the cutting method (means) for cutting the glass ribbon in the width direction for products is not particularly limited, and can be selected based on the required cutting surface shape, cutting accuracy, and the like. .

The form of the thin glass that can be cut in the width direction cutting step is not limited, and may be, for example, a glass sheet that has been cut in the width direction into a predetermined sheet size, or a glass obtained by winding a predetermined amount of thin glass. It may be a roll.

Although each process has been described above, a configuration example of a thin glass manufacturing apparatus that can be used in the thin glass manufacturing method of the present embodiment will be described with reference to FIGS.

FIG. 2 is a schematic view of a manufacturing apparatus for thin glass when the float method is used in the forming process.

2, first, a glass raw material is charged into the melting furnace 21 to obtain a molten glass 22. Then, molten glass is supplied onto the molten tin 24 in the float bath 23, and the molten glass is formed into a glass ribbon 25. The formed glass ribbon 25 is gradually cooled and cooled by being held and transported on the transport roller 26. At this time, a slow cooling furnace 27 can be provided around the transport roller 26 in order to cool and cool the glass ribbon at an appropriate cooling rate. The glass ribbon that has been gradually cooled and cooled can be cut into a desired size by the width direction cutting device 28.

A method for adjusting the thickness of the glass ribbon in the float process will be described with reference to FIG. FIG. 3 shows a cut surface taken along the line AA ′ of the float bath of FIG.

As shown in FIG. 3, in the float bath, molten glass is supplied onto the molten tin 24 from the left side in the drawing, and is formed into a glass ribbon while being conveyed on the molten tin 24 to the right side in the drawing.

¡By pressing the glass ribbon from above with a rotating roller (top roller) called an auxiliary roller, the shrinkage of the glass ribbon width can be suppressed, and the thickness of the central portion and the width of the glass ribbon can be selected and adjusted. As described above, in the float process, the end of the glass ribbon is pressed by the rotating roller to perform the forming process, and therefore, as shown in FIG. become.

Next, the outline of the structure of the apparatus for producing thin glass when the fusion method is used in the forming process will be described with reference to FIG.

In FIG. 4, although the description of the melting step is omitted, it can be configured similarly to the case of the float process.

Then, the molten glass obtained in the melting step is supplied to a groove (not shown) provided on the upper surface of the fusion pipe 41 in FIG. 4, and the overflowing molten glass 42 is integrated at the lower part of the fusion pipe to form a single glass. The ribbon 43 is continuously formed. At this time, in order to form the glass ribbon while supporting both ends thereof so that the glass ribbon does not shrink in the width direction at the lower part of the fusion pipe, the thickness in the cross section in the width direction as shown in FIG. Will result in a distribution.

Thereafter, the glass ribbon 43 is transported on the transport roller 44 to be gradually cooled and cooled. At this time, as in the case of the float process, for example, as shown by a dotted line in the figure, a slow cooling furnace can be provided around the transport roller to control the temperature of the slow cooling step.

A width direction cutting device 46 is provided downstream of the transport roller 44 in the transport direction. Thereby, it can cut | disconnect to a desired size.

In FIG. 4, the thin glass is wound into a roll to form a glass roll. However, in addition to such a form, it can be cut into a sheet of a predetermined size as described above to form a glass sheet.

In FIG. 4, the arrangement of the conveying rollers includes a portion 47 that conveys the glass ribbon in the horizontal direction, but in this way also in the thin glass manufacturing apparatus (manufacturing method) by the fusion method, the horizontal portion is arranged on the conveying path. It is preferable to include.

This is because the present invention tries to suppress the phenomenon that the front end portion of the glass ribbon is bent by its own weight and the transport roller cannot pass when the glass ribbon is transported by the transport roller at the start of production. It is easy to occur in the place where was arranged horizontally. For this reason, since the direction which has the conveyance process which conveys a glass ribbon with a conveyance roller in a horizontal direction can improve the effect of this invention more, it is preferable.

And in the manufacturing method of the thin glass of this embodiment, at the time of manufacture start, let the plate | board thickness of the glass ribbon at least the conveyance direction front-end | tip part be the thickness which can pass the conveyance roller in a conveyance process at the formation process. Furthermore, after the conveyance direction front-end | tip part of a glass ribbon passes the width direction cutting process, the plate | board thickness of the glass ribbon shape | molded by the said formation process is changed into the thickness for products.

The thickness of the front end of the glass ribbon in the conveyance direction at the start of production will be described with reference to FIG. FIGS. 5A and 5B show a configuration example of a cross-sectional view when the leading end portion of the glass ribbon 51 at the start of manufacture and the portion subsequent thereto are transported on the transport roller.

In Fig.5 (a), the plate | board thickness 52 of the glass ribbon including the front-end | tip part of a glass ribbon is shape | molded by the thickness which can pass the conveyance roller in an conveyance process in the above-mentioned formation process, Thicker than the product thickness.

For this reason, the glass ribbon shown in FIG. 5 (a) is less likely to bend as compared with the case where the thickness of the glass ribbon for the product is made from the beginning as shown in FIG. It is possible to pass through.

At this time, as a method for defining (selecting) the thickness 52 of the tip of the glass ribbon, the following methods may be mentioned.

First, roller specifications such as roller pitch are determined from the width of the glass ribbon to be produced and the specifications of the manufacturing equipment for the thin glass, and the allowable deflection amount in the manufacturing equipment can be calculated.

On the other hand, the amount of static deflection as a cantilever beam corresponding to the roller pitch is numerically calculated from the thickness of the glass ribbon to be produced, the width and cross-sectional shape in the width direction (= thickness distribution), and the elastic modulus and specific gravity of the glass. It can be estimated by simulation or the like. Furthermore, it is possible to estimate the maximum dynamic deflection amount in consideration of vibrations of the transport facility and the like.

Then, the allowable deflection amount and the maximum dynamic deflection amount multiplied by a safety factor are compared. If the allowable deflection amount is larger, it can be determined that the glass ribbon having the thickness is stably conveyed. .

In other words, the glass ribbon has a thickness that allows the allowable deflection calculated from the manufacturing equipment to be greater than the product of the maximum dynamic deflection calculated from the glass ribbon to be produced (shape, material, etc.) and the safety factor. The thickness 22 at the front end in the transport direction can be set to a thickness that can pass through the transport roller in the transport process.

Although FIG. 5A shows an example in which the glass ribbon is uniformly thick, any thickness may be used as long as at least the front end of the glass ribbon in the transport direction can pass through the transport roller at the start of manufacture. For this reason, for example, as shown in FIG. 5B, the thickness 53 that can pass through the transport roller in the vicinity of the front end may be set, and the plate thickness 53 in this case is also selected based on the same calculation as described above. can do.

However, when changing the thickness of the glass ribbon, if the glass ribbon is changed suddenly, the glass ribbon may break, so the thickness is increased over a certain range as shown in FIG. It is preferable to change the thickness.

And the glass ribbon may have a plate thickness distribution in the width direction as described above. A specific example is shown in FIG. FIG. 6A shows a cross section in the width direction of the glass ribbon (direction perpendicular to the conveying direction) when the float method is used in the forming step, and FIG. 6B shows the case where the fusion method is used in the forming step. The shape is shown.

When formed by the float process or the fusion method, as shown in FIG. 6, generally, the

central portions

611 and 621 of the glass ribbon are portions that become products, and both end

portions

612 and 622 are thicker than the central portion. It has become. This is to form the glass ribbon while pulling or holding the both ends of the glass ribbon with a roller or the like in the forming step so that the central portion of the glass ribbon has a predetermined thickness.

And, as described above, when calculating the maximum dynamic deflection amount, the cross-sectional shape (plate thickness distribution) in the width direction of the glass ribbon is used as an element of calculation. For this reason, when controlling the plate thickness so that the entire glass ribbon can pass over the transport roller, the plate thickness is set to a predetermined value (for each portion in the width direction) at least at the tip of the glass ribbon. Will be.

Next, after the front end of the glass ribbon in the conveyance direction passes through the width direction cutting step, the thickness of the glass ribbon formed in the forming step is changed to a thickness for products.

After the leading end of the glass ribbon in the conveyance direction passes through the width direction cutting step, the glass ribbon is a continuous glass ribbon from the forming step to the width direction cutting step. That is, the tip of the glass ribbon does not exist upstream of the width direction cutting step.

Since there is no tip of the glass ribbon that can not pass the transport roller upstream of the width direction cutting step in this way, the thickness of the glass ribbon is changed to a thickness for products that is thinner than at the start of production. However, it is possible to pass through the transport roller stably.

Here, changing the thickness of the glass ribbon to the thickness for the product means that when the glass ribbon has a thickness distribution in the width direction as shown in FIG. 6, the

product portions

611 and 621 at the center portion thereof. This means that the part is molded so as to have a product thickness (target thickness).

The method of changing the thickness of the glass ribbon to the product thickness is preferably performed by one or more methods selected from the following methods. That is, it can be performed by only one method selected from the following methods, or can be performed by combining two or more.

Method of increasing the conveyance speed of the glass ribbon in the molding process.

Method to reduce the supply amount (per unit time) of molten glass to the molding process (slow supply speed).

¡How to widen the glass ribbon.

¡Method to change the thickness distribution in the width direction of the glass ribbon.

Any of the above methods is preferable because the thickness of the product portion of the glass ribbon can be easily changed.

Note that the thickness of the glass ribbon may be the thickness for the product, as described above, may be performed immediately after the front end of the glass ribbon in the conveyance direction passes through the width direction cutting step, but after a certain time has passed. May be. However, in any case, if the thickness of the glass ribbon in the molding process is suddenly changed, the glass ribbon may be cut during the transport process, so gradually (for example, taking about 1 hour to 1 day). It is preferable to reduce the thickness of the glass ribbon to a final product thickness.

In addition, when the production of multiple types of glass thickness is planned, the process of reducing the glass ribbon thickness is used to produce products with increasing thickness in the order of their thickness. In addition, it is preferable from the viewpoint of productivity that the glass ribbon is manufactured in accordance with (changed) the thickness of the product having the smallest thickness. That is, for example, a lot of glass with a thick plate (for example, 0.7 mm or more) is first produced, then a glass with a thin plate (for example, 0.3 mm) is produced, and then a plate is produced. Thin lots of glass (eg, 0.2 mm or less) may be produced.

And in the manufacturing method of the sheet glass demonstrated by this embodiment, in addition to the width direction cutting process mentioned above, it can have the both ends cutting process which cut | disconnects the width direction both ends (ear | edge part) of a glass ribbon. This will be described below.

As described above, the glass ribbon which is the object to be cut is, for example, one formed by the float method or the fusion method, which has been cooled during the conveying process. And the glass ribbon shape | molded by the float glass process or the fusion method may produce the part from which thickness differs from the center part in the both ends of the width direction so that it may mention later. For this reason, it will cut also about the both ends of the width direction of a product. This point will be described with reference to FIG.

7A is a view of the glass ribbon as viewed from above, and FIG. 7B is a cross-sectional view of the glass ribbon in the width direction when the glass ribbon is viewed from the direction of arrow A in FIG. 7A. Is shown.

FIG. 7B is a cross-sectional view in the width direction of the glass ribbon when the glass ribbon is formed by the fusion method as already shown. In this case, the glass ribbon transport direction (indicated by a block arrow in FIG. 7A). As for the cross section in the vertical direction, the both end portions 71 are thicker than the center portion 72 which is a product.

When the glass ribbon has such a shape, in addition to cutting in the width direction along the dotted line Y shown in FIG. 7A to obtain a thin glass sheet having a desired length, both end portions (ear portions) 71 are removed. Therefore, it can also cut | disconnect also in the dotted line X shown to Fig.7 (a).

Although either the dotted line X or the dotted line Y can be cut first, it is preferable to cut the dotted line Y after cutting the dotted line X.

That is, it is preferable to have the both-ends cutting process which cut | disconnects the width direction both ends of a glass ribbon before the width direction cutting process.

The both ends cutting step and the width direction cutting step will be described with reference to FIG.

FIG. 8 (a) schematically shows a configuration of the glass ribbon cut by the above procedure as seen from the upper surface side, and FIG. 8 (b) is seen from the arrow B in FIG. 8 (a). The schematic diagram of the side is shown.

In the both end cutting step and the width direction cutting step, the glass pieces and the like generated at the time of cutting are transported to the width direction cutting device 84 by a plurality of transport rollers 81 so as not to remain on the transport path.

In addition, up to the width direction cutting device 84 is a single glass ribbon 82 that continues from the molding process.

As shown in FIG. 8, both ends of the glass ribbon 82 continuously conveyed by the conveying roller 81 are cut along the cutting line indicated by the dotted line X in FIG. Cut with.

After that, the glass ribbon is further transported by the transport roller 81, cut by the width direction cutting device 84 so as to have a desired length of the thin glass, and transported to a product storage place (not shown) by the belt conveyor 85. It becomes.

In this case, before the both ends of the glass ribbon are cut by the both ends cutting device 83, the plate thickness at both ends is thick as described above, so that the maximum thickness of the glass ribbon as shown in FIG. It has a thickness of T1.

However, the maximum thickness of the glass ribbon after passing through the both end cutting device 83 is T2 which is thinner than T1. This is because, as described with reference to FIG. 7B, the glass ribbon after passing through the both-end cutting device is only the product portion (center portion) 72 having a thin plate thickness.

For this reason, the portion of the glass ribbon that has passed through the both-end cutting device is particularly flexible because it is thin. Accordingly, when the product thickness at the front end of the glass ribbon in the conveyance direction is set as a target plate thickness from the beginning of manufacture, it is more difficult to pass through the conveyance roller between the both-end cutting device and the width direction cutting device.

On the other hand, in the manufacturing method of the thin glass of this embodiment, the thickness of the front end portion in the conveyance direction of the glass ribbon is increased at the start of manufacture, and the front end portion passes through the width direction cutting device (in the width direction). After passing through the cutting process) Change the thickness of the glass ribbon. For this reason, the front-end | tip part of a glass ribbon can reach | attain to a width direction cutting device part more reliably.

The specific cutting method in the width direction cutting step and the both end cutting step described here is not limited, and can be performed by cleaving or fusing using laser light, for example. Different cutting methods may be used in the width direction cutting step and the both end cutting step.

When cutting by cleaving, the cleaving is generally divided into two stages: a scribing process for forming a crease line (scribe line) and a cleaving process for actually dividing (cutting) the glass ribbon from the scribe line formed in the scribing process. It is performed by a process.

And, as described above, the width direction cutting step is performed after the both end cutting step (for example, when both cutting steps are performed by cleaving) after the cleaving step of actually dividing the both ends (ear portions) of the glass ribbon. A cleaving process for actually dividing the direction may be performed, and the order of the scribing process for each portion is not limited.

That is, for example, after performing the scribing process for both ends of the glass ribbon and the scribing process for the width direction (the order of the scribing process is not limited), the cleaving process for dividing the both ends of the glass ribbon, the cutting along the width direction The method of performing the cleaving process to perform in that order may be used.

Moreover, you may perform a scribing process and a cleaving process in order about each cutting process. That is, after performing the scribing process for both ends of the glass ribbon, the cleaving process for dividing both ends of the glass ribbon, the scribing process for the width direction of the glass ribbon and the cleaving process for dividing along the width direction of the glass ribbon are performed in this order. May be.

In the manufacturing method of the thin glass of the present embodiment, when the both-end cutting step and the width direction cutting step are applied in the order described here, the thickness for the product of the glass ribbon formed in the forming step is the glass ribbon. It is preferable that the plate | board thickness of the width direction center part (product part) is 0.3 mm or less.

This is because when a glass ribbon with the thickness of the width direction center part (product part) at the front end in the transport direction at the start of the manufacture is supplied, it is particularly difficult to pass the transport roller after the both ends cutting device. This is because, according to the method described in the present embodiment, it is possible to pass through the transport roller more reliably, and the effect is particularly exhibited.

Further, the thickness of the glass ribbon in the center in the width direction is more preferably 0.2 mm or less, further preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

The lower limit of the thickness of the glass ribbon in the width direction center (product part) is not particularly limited, but the conveyance speed is such that the glass ribbon does not break during conveyance from the forming step to the width direction cutting step. It is preferable to select according to the type and characteristics of the glass. For example, the lower limit value of the thickness of the central portion in the width direction of the glass ribbon is preferably 0.01 mm or more, more preferably 0.02 mm or more, particularly 0.03 mm or more, based on stable production conditions based on the glass forming principle. preferable.

The plate thickness at the center in the width direction of the glass ribbon here refers to the thickness of the glass ribbon formed in the forming step after the leading end in the conveyance direction of the glass ribbon passes through the width direction cutting step. For example, the thicknesses of the product portions (center portions) 612 and 622 in FIG.

In addition, when cut | disconnecting the dotted line X after cut | disconnecting the dotted line Y shown to Fig.7 (a), ie, when performing a both-ends cutting process after performing a width direction cutting process previously, the glass shape | molded by the said formation process The thickness of the ribbon product is preferably 0.2 mm or less at the center in the width direction of the glass ribbon.

This is because the tip of the glass ribbon cannot pass through the transport roller until the cutting process in the width direction when it is formed to have such a thickness from the start of manufacturing as in the past, but the manufacturing method of the present embodiment is reliable. This is because it becomes possible to pass through the transport roller up to the width direction cutting step and exerts its effect.

And, as described above, after the leading end of the glass ribbon reaches the width direction cutting step, it becomes one glass ribbon continuous from the forming step to the width direction cutting step, upstream from the width direction cutting step. The tip of the glass ribbon does not exist. Thus, when the leading end of the glass ribbon that causes the conveyance roller to not pass on the upstream side of the width direction cutting step does not exist, the thickness of the glass ribbon is reduced for products in the above range that is thinner than at the start of production. Even if it changes to plate | board thickness, it becomes possible to pass a conveyance roller.

Since the glass after passing through the width direction cutting step is lowered to a temperature close to room temperature, the above-described restrictions on the diameter and pitch of the conveying roller are reduced, and various conveying methods (small-diameter conveying rollers, belt conveying, air floating) Transport etc.) can be selected.

Further, the thickness of the central portion in the width direction of the glass ribbon is more preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

In addition, the thickness of the product part of the glass ribbon is as described above. Further, the lower limit value of the thickness of the glass ribbon in the width direction central portion (product portion) is not particularly limited as described above, and the thickness at which the glass ribbon does not break during conveyance from the forming step to the width direction cutting step. Furthermore, it can select according to the conveyance speed, the kind of glass, a characteristic, etc. Specifically, for example, 0.01 mm or more is preferable, 0.02 mm or more is more preferable, and 0.03 mm or more is particularly preferable from the stable production conditions based on the glass forming principle.

As described above, according to the method for manufacturing the thin glass of the present embodiment described above, the glass ribbon can pass more reliably on the transport roller at the start of manufacturing (when the manufacturing apparatus is started up), and the yield is improved. And productivity can be improved.

Specific examples and comparative examples will be described below, but the present invention is not limited to these examples.
[Example 1]
In this example, a thin glass plate was produced according to the following procedure.
(Melting step) Glass raw materials were mixed so as to be alkali-free glass, and this was supplied to a melting furnace to obtain molten glass.
(Molding process) Molten glass from a melting furnace was supplied onto molten tin in a float bath and molded into a glass ribbon.

At this time, at the start of production, the glass ribbon was continuously formed such that the plate width was 4.6 m, and the thickness of the central portion (product portion) (611 portion in FIG. 6A) was 0.3 mm. The shape of the glass ribbon confirms in advance that the allowable deflection amount of the manufacturing equipment is larger than the product of the maximum dynamic deflection amount of the glass ribbon and the safety factor.
(Conveying process) The glass ribbon which the roller pitch was set to 450 mm and was shape | molded by the said formation process on the conveying roller arrange | positioned in multiple numbers was conveyed.
(Width direction cutting process) The glass ribbon was cut | disconnected so that it might become desired length about the glass ribbon conveyed to the cutting device by the conveyance process.
(Both ends cutting process) About the glass sheet used as the desired length in the width direction cutting process, it cut about the both ends of the width direction.

That is, after cutting along the Y cutting line in FIG. 7A, cutting was performed along the X cutting line.

And in the said manufacturing process, after confirming that the front-end | tip part of a glass ribbon passes a width direction cutting process, in the said formation process, as a shape of the glass ribbon to shape | mold, plate width remains 4.6m, The product thickness (611 portion in FIG. 6A) was changed to 0.1 mm. The thickness of the product section is changed by changing the thickness distribution in the width direction in the glass ribbon with the top roller shown in FIG. 3 and the method of increasing the conveyance speed of the glass ribbon, This was done by combining methods for reducing the supply amount.

In this example, the leading end of the glass ribbon in the conveyance direction was able to pass through the width direction cutting step even at the start of production. Further, it was confirmed that the glass ribbon was continuously conveyed on the conveying roller without being cut even after the thickness of the product portion was changed.
[Comparative Example 1]
In this comparative example, in the molding process, the glass ribbon was set to the desired size of the final product at the start of manufacture, that is, the plate width was 4.6 m, and the thickness of the central portion (product portion) was 0.1 mm. Production of the thin glass was started in the same manner as in Example 1 except that it was shaped so as to be.

At this time, in the shape of the glass ribbon, the allowable deflection amount of the manufacturing equipment was smaller than the product of the maximum dynamic deflection amount of the glass ribbon and the safety factor.

When manufacturing of thin glass was started under the conditions of this comparative example, the glass ribbon formed in the forming process could not pass on the transport roller in the transport process and could not reach the width direction cutting process. It was not possible to produce thin glass with the desired specifications.

The present invention is suitable for manufacturing plate glass and the like.

This application is based on Japanese Patent Application No. 2012-177513 filed with the Japan Patent Office on August 9, 2012, claims the priority thereof, and refers to the entire contents of the application. It is included.

22, 42

Molten glass

25, 43, 51, 82

Glass ribbon

26, 44, 81 Conveying roller

Claims

A melting step of melting a glass raw material into a molten glass;
A molding process for forming molten glass into a glass ribbon;
A conveying step of conveying the glass ribbon by a conveying roller;
A width direction cutting step of cutting the glass ribbon in the width direction,
At the start of production, the thickness of at least the leading end of the glass ribbon in the forming step is set to a thickness that can pass through the transfer roller in the transfer step,
The manufacturing method of the sheet glass which changes the plate | board thickness of the glass ribbon shape | molded by the said formation process to the thickness for products after the conveyance direction front-end | tip part of the said glass ribbon passes the said width direction cutting process.
The method of changing the thickness of the glass ribbon molded in the molding process to the thickness for the product,
A method of increasing the conveyance speed of the glass ribbon in the molding step;
A method of reducing the amount of molten glass supplied to the molding step;
A method of widening the width of the glass ribbon;
The method for producing a thin glass according to claim 1, wherein the method is performed by one or more methods selected from a method of changing a thickness distribution in the width direction of the glass ribbon.
The manufacturing method of the sheet glass of Claim 1 or 2 which has the both-ends part cutting process which cut | disconnects the width direction both ends of the said glass ribbon before the said width direction cutting process.
The thickness of the glass ribbon product to be formed in the forming step, wherein the thickness of the glass ribbon at the center in the width direction is 0.3 mm or less. Method.
The thickness for the product of the glass ribbon to be formed in the forming step, wherein the thickness of the glass ribbon in the center in the width direction is 0.2 mm or less. The manufacturing method of sheet glass of description.
The method for producing a thin glass according to any one of claims 1 to 5, wherein a width of the glass ribbon after changing the thickness of the glass ribbon to a thickness for a product is 1.5 m or more.
The roller pitch of the conveyance roller in the said conveyance process is 200 mm or more, The manufacturing method of the sheet glass as described in any one of Claim 1 thru | or 6.