Manufacturing methods for molded articles and glass articles

Abstract

This method suppresses creep deformation of the molded body without increasing its size. [Solution] The molded body 6 comprises a groove 9, a pair of outer surfaces 6b that allow molten glass Gm overflowing from the groove 9 to flow downward, and a lower end portion 6c that allows the molten glass Gm flowing on the pair of outer surfaces 6b to merge. The outer surfaces 6b of the molded body 6 have a pair of vertical surfaces 12 and a pair of inclined surfaces 13 that are connected below the vertical surfaces 12. At least a portion 9d1 of the bottom surface 9d of the groove 9 is located below the upper edge portion 13a1 of the inclined surface portion 13.

Description

Technical Field

[0001] The present invention relates to a molding body for molding a glass article and a method for manufacturing a glass article.

Background Art

[0002] As a method for manufacturing a glass article such as a glass plate, an overflow down-draw method may be used. The molding apparatus used in this manufacturing method includes a substantially wedge-shaped molding body. The molten glass supplied to the molding body overflows in two directions from the groove formed at the top of the molding body, and then converges at the lower end portion along both outer surfaces of the molding body (see, for example, Patent Document 1).

[0003] Thereby, a strip-shaped glass ribbon is continuously formed from the molten glass. According to this manufacturing method, since the front and back surfaces of the formed glass ribbon do not contact the molding body during the molding process, there is an advantage that a smooth glass ribbon without scratches or the like on the front and back surfaces can be formed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the molding body performs molding of high-temperature molten glass, creep deformation occurs over time. In order to suppress creep deformation, it is conceivable to increase the size of the molding body to enhance rigidity. However, an increase in the manufacturing cost of the molding body due to the increase in size has been a problem.

[0006] The present invention has been made in view of the above circumstances, and its technical problem is to suppress creep deformation of the molding body without causing an increase in the size of the molding body.

Means for Solving the Problems

[0007] (1) The present invention is for solving the above problems and is a long molded body for forming a glass ribbon from molten glass by an overflow method, wherein the molded body has a groove formed at its upper part, a pair of outer surfaces that allow the molten glass overflowing from the groove to flow downward, and a lower end that brings together the molten glass flowing on the pair of outer surfaces, the groove has an inner surface and a bottom surface, the pair of outer surfaces of the molded body have a pair of vertical surfaces and a pair of inclined surfaces that are connected below the vertical surfaces, the lower end of the molded body is formed by the intersection of the lower edges of the pair of inclined surfaces, and at least a part of the bottom surface of the groove is located below the upper edge of the inclined surfaces.

[0008] With this configuration, by forming a portion of the bottom surface of the groove in the molded body below the upper edge of the inclined surface on the outer surface, the depth of the groove can be increased as much as possible. This makes it possible to lower the temperature of the molten glass supplied to the groove and suppress creep deformation of the molded body as much as possible. Moreover, since this invention modifies the shape of the groove, which is the internal structure of the molded body, it does not lead to an increase in the size of the molded body.

[0009] (2) In the molded body described in (1) above, the groove is configured to be elongated along the longitudinal direction of the molded body, and the groove has a first end to which the molten glass is supplied and a second end located on the opposite side of the first end in the longitudinal direction of the groove, and at least a portion of the bottom surface of the groove may be located on the side of the first end.

[0010] With this configuration, by forming at least a portion of the bottom surface at the first end of the groove below the upper edge of the inclined surface on the outer surface, the depth of the bottom surface at the first end of the groove can be made as large as possible. This allows for a further reduction in the temperature of the molten glass supplied to the groove.

[0011] Furthermore, since the second end of the groove is located away from the first end, the molten glass supplied to the first end of the groove is more likely to overflow from the first end and less likely to overflow from the second end. In this invention, by ensuring a greater depth in a portion of the bottom surface on the first end side, the molten glass can be uniformly discharged from the groove over the entire range from the first end to the second end.

[0012] (3) In the molded body described in (1) or (2) above, the groove portion has a chamfered portion connecting the inner surface and the bottom surface, and the chamfered portion may be configured to be curved or flat.

[0013] With this configuration, the rigidity of the molded body can be increased, and creep deformation of the molded body can be suppressed as much as possible. In addition, the depth of the groove can be made even deeper, and the temperature of the molten glass supplied to the groove can be further reduced.

[0014] (4) In the molded body described in any of (1) to (3) above, the upper part of the inclined surface is connected to the vertical surface, and the upper part of the inclined surface may be configured in a curved shape.

[0015] With this configuration, the rigidity of the molded body can be increased, and creep deformation of the molded body can be suppressed as much as possible. In addition, the depth of the groove can be made even deeper, and the temperature of the molten glass supplied to the groove can be further reduced.

[0016] (5) The present invention is for solving the above problems and is a method for manufacturing a glass article using a molded body as described in any of (1) to (4) above, characterized in that it comprises a molding step of allowing the molten glass overflowing from the groove of the molded body to flow along the pair of outer surfaces of the molded body, and converging the molten glass flowing along the pair of outer surfaces at the lower end of the molded body.

[0017] According to such a configuration, by forming a part of the bottom surface in the groove portion of the molded body below the upper edge portion in the inclined surface portion of the outer surface, it is possible to suppress the creep deformation of the molded body in the molding process without causing an increase in the size of the molded body.

Effect of the Invention

[0018] According to the present invention, it is possible to suppress the creep deformation of the molded body without causing an increase in the size of the molded body.

Brief Description of the Drawings

[0019] [Figure 1] It is a side view showing a manufacturing apparatus for a glass article. [Figure 2] It is a front view showing a manufacturing apparatus for a glass article. [Figure 3] It is a front view of the molded body. [Figure 4] It is a cross-sectional view taken along the line IV-IV of FIG. 3. [Figure 5] It is a flowchart showing a method for manufacturing a glass article.

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIGS. 1 to 5 show an embodiment of the present invention. In the orthogonal coordinate system composed of XYZ shown in the figures, the X direction and the Y direction are horizontal directions, and the Z direction is the vertical direction. Also, the direction corresponding to the width direction of the glass ribbon to be formed is called the width direction X, and the direction corresponding to the thickness direction of the glass ribbon to be formed is called the thickness direction Y.

[0021] Figs. 1 and 2 show a manufacturing apparatus for glass articles. The manufacturing apparatus 1 includes a forming furnace 2, a lehr 3 located below the forming furnace 2, a cooling chamber 4 located below the lehr 3, and a cutting chamber 5 located below the cooling chamber 4. Between the forming furnace 2 and the lehr 3, between the lehr 3 and the cooling chamber 4, and between the cooling chamber 4 and the cutting chamber 5, partition members (e.g., the floor surface of a building) F1, F2, F3 having openings (e.g., slits) through which the glass ribbon Gr passes are provided respectively to partition them.

[0022] As shown in Figs. 1 and 2, the forming furnace 2 is a region for forming a glass ribbon Gr from molten glass Gm by the overflow down-draw method. The forming furnace 2 includes, inside thereof, a forming body 6 for forming a glass ribbon Gr from molten glass Gm, pressing members 7a, 7b for pressing the forming body 6, and a first conveying roller 8 for cooling both end portions in the width direction X of the glass ribbon Gr formed by the forming body 6.

[0023] The forming body 6 is formed of a long refractory along the width direction X. Examples of the refractory include zircon-based, zirconia-based, alumina-based, magnesia-based, xenotime-based, etc. The forming body 6 has an upper portion 6a to which molten glass Gm is supplied, a pair of outer surfaces 6b for flowing the molten glass Gm downward, and a lower end portion 6c for forming the molten glass Gm flowing on the pair of outer surfaces 6b.

[0024] The length L of the molded body 6 in the width direction X (see Figure 3) is preferably 2000 mm or more, more preferably 2500 mm or more, and even more preferably 3000 mm or more. On the other hand, the upper limit of the length L of the molded body 6 is preferably 4000 mm or less. The length of the molded body 6 in the vertical direction Z is longest at one end in the longitudinal direction and shortest at the other end in the longitudinal direction. That is, the length of the molded body 6 in the vertical direction Z is set to gradually decrease from one end to the other. The length H1 in the vertical direction Z at one end of the molded body 6 is preferably 500 mm or more and 1000 mm or less. The length H2 in the vertical direction Z at the other end of the molded body 6 is preferably 400 mm or more and 800 mm or less.

[0025] The upper part 6a of the molded body 6 has an elongated groove (overflow groove) 9 formed along the width direction X (the longitudinal direction of the molded body 6), and a pair of top surfaces 10 connected to the groove 9. A supply pipe 11 for supplying molten glass Gm is connected to one end 9a of the groove 9 in the longitudinal direction (width direction X). Hereinafter, the end 9a of the groove 9 will be referred to as the first end, and the end 9b located on the opposite side of the first end 9a in the width direction X (the longitudinal direction of the groove 9) will be referred to as the second end.

[0026] As shown in Figures 3 and 4, the groove 9 of the molded body 6 has an inner surface 9c, a bottom surface 9d, and a chamfered portion 9e connecting the inner surface 9c and the bottom surface 9d.

[0027] As shown in Figure 4, the inner surface 9c of the groove 9 has a pair of opposing vertical surfaces in the thickness direction. The spacing (groove width) W of the pair of vertical surfaces in the thickness direction Y is preferably 0.5 to 0.8 times the thickness T1 of the upper part 6a of the molded body 6 (0.5T1 ≤ W ≤ 0.8T1). This spacing W is preferably set to be constant along the entire length of the groove 9.

[0028] As shown in Figure 3, the depth dimension of the groove 9 differs in the longitudinal direction (width direction X) of the groove 9. The depth dimension of the groove 9 is set to gradually decrease from the first end 9a to the second end 9b. Therefore, the depth dimension of the groove 9 is largest at the first end 9a and smallest at the second end 9b.

[0029] As shown in Figure 3, the bottom surface 9d of the groove 9 is inclined to gradually move upward from the first end 9a to the second end 9b.

[0030] As shown in Figure 4, the chamfered portion 9e of the groove 9 is configured as a curved surface (R chamfer), but it is not limited to this, and may be configured as a flat surface (C chamfer), for example. The radius of curvature or chamfer dimension of the chamfered portion 9e is preferably 2 mm or more and 30 mm or less.

[0031] The molded body 6 has a symmetrical shape in the thickness direction Y. The outer surface 6b of the molded body 6 has a pair of vertical surfaces 12 that are planar along the vertical direction Z, and a pair of inclined surfaces 13 that are connected below the vertical surfaces 12 and are inclined with respect to the vertical direction Z.

[0032] As shown in Figure 4, the pair of vertical surfaces 12 are configured to be parallel to each other. The vertical surfaces 12 are also configured to be parallel to the inner surface 9c of the groove 9. The upper part of the vertical surface 12 is connected to the top surface 10, and the lower part of the vertical surface 12 is connected to the inclined surface 13.

[0033] The vertical surface portion 12 may be inclined within an angular range of ±5° with respect to the vertical direction Z. If the inclination angle is larger than this range, it is undesirable because it is likely to cause unevenness in the flow of molten glass Gm along the vertical surface portion 12.

[0034] As shown in Figures 3 and 4, the inclined surface portion 13 has an upper part 13a and a lower part 13b. The upper part 13a of the inclined surface portion 13 is connected to the vertical surface portion 12 at its upper edge 13a1. This upper edge 13a1 is located at the boundary between the upper part 13a and the vertical surface portion 12.

[0035] The upper part 13a of the inclined surface 13 is configured as a curved surface that is convex outward, and the lower part 13b of the inclined surface 13 is configured as a flat surface. The radius of curvature of the upper part 13a is preferably 400 mm or more and 800 mm or less.

[0036] By providing a chamfered portion 9e in the groove portion 9 and / or making the upper part 13a of the inclined surface portion 13 curved, the gap T2 (see Figure 4) between the bottom surface 9d on the first end 9a side of the groove portion 9 and this upper part 13a can be made larger. This increases the rigidity of the molded body 6, thereby suppressing creep deformation of the molded body 6. In addition, the depth D1 of the groove portion 9 can be made even deeper, and the temperature of the molten glass Gm supplied to the groove portion 9 can be further reduced.

[0037] As shown in Figure 4, the pair of inclined surfaces 13 are inclined so that they approach each other in the thickness direction Y as they extend downwards. In other words, the molded body 6 takes on a wedge shape that tapers downwards when viewed from the width direction X, due to the formation of each inclined surface 13. Furthermore, a corner is formed where the lower edges of the pair of inclined surfaces 13 intersect. This corner constitutes the lower end portion 6c of the molded body 6.

[0038] As shown in Figure 3, the upper part 13a of the inclined surface 13 is such that a portion of the upper edge 13a1 on the first end 9a side of the groove 9 is located above a portion 9d1 of the bottom surface 9d of the groove 9. In other words, as shown in Figures 3 and 4, a portion 9d1 of the bottom surface 9d on the first end 9a side of the groove 9 is located below the upper edge 13a1 of the upper part 13a of the inclined surface 13.

[0039] As shown in Figure 3, the length L2 of a portion 9d1 of the bottom surface 9d is preferably 0.2 times or more and 0.5 times or less (0.2L ≤ L2 ≤ 0.5L) the total length L of the molded body 6, and more preferably 0.3 times or more and 0.4 times or less.

[0040] The distance H2 (see Figure 4) in the vertical Z between a part 9d1 of the bottom surface 9d and the upper edge 13a1 of the inclined surface 13 is preferably 0.5 to 0.9 times the length H1 in the vertical Z at one end of the molded body 6 (0.5H1 ≤ H2 ≤ 0.9H1).

[0041] The pressing members 7a and 7b are for suppressing creep deformation of the molded body 6 and press the longitudinal ends of the molded body 6. The pressing members 7a and 7b are made of, for example, firebrick. As shown in Figure 2, the pressing members 7a and 7b include a first pressing member 7a that presses one end of the molded body 6 in the width direction X, and a second pressing member 7b that presses the other end of the molded body 6.

[0042] The first pressing member 7a and the second pressing member 7b are arranged to face each other in the width direction X, and by sandwiching the molded body 6, they can apply a pressing force (pressing force) to the molded body 6 in the width direction X.

[0043] As shown in Figures 1 and 2, the first conveyor roller 8 is configured as a pair of rollers that grip each end of the glass ribbon Gr in the width direction X in the thickness direction Y, directly below the molded body 6. The first conveyor roller 8 is a cantilever type roller and has a cooling mechanism inside. The first conveyor roller 8 is also called a cooling roller or edge roller.

[0044] As shown in Figures 1 and 2, the annealing furnace 3 is a region for reducing warping and internal distortion of the glass ribbon Gr. Inside the annealing furnace 3, a second conveyor roller 14 is arranged. The second conveyor roller 14 is also called an annealer roller. The second conveyor roller 14 is configured as a pair of rollers that clamp each end of the glass ribbon Gr in the width direction X in the thickness direction Y. The second conveyor roller 14 may be a double-supported type roller arranged to span the entire width direction X of the glass ribbon Gr, but in this embodiment, it is a cantilevered type roller. Multiple stages of the second conveyor roller 14 are provided in the vertical direction Z.

[0045] As shown in Figures 1 and 2, the cooling chamber 4 is a region for cooling the glass ribbon Gr to near room temperature. Inside the cooling chamber 4, a third conveyor roller 15 is arranged. The third conveyor roller 15 is configured as a pair of rollers that clamp each end of the glass ribbon Gr in the width direction X in the thickness direction Y. The third conveyor roller 15 may be a double-supported type roller that spans the entire width direction X of the glass ribbon Gr, but in this embodiment, it is a single-supported type roller. Multiple stages of the third conveyor roller 15 are provided in the vertical direction Z.

[0046] In this embodiment, the ends of the glass ribbon Gr obtained in the manufacturing apparatus 1 in the width direction X include tabs that are thicker than the central part in the width direction X due to the effects of shrinkage during the molding process.

[0047] As shown in Figures 1 and 2, the cutting chamber 5 is a region for cutting the glass ribbon Gr to a predetermined size to obtain a glass plate G as a glass article. A cutting device (not shown) for cutting the glass ribbon Gr is arranged inside the cutting chamber 5. In this embodiment, the method of cutting the glass ribbon Gr by the cutting device is scribe cutting, in which a scribe line is formed on the glass ribbon Gr and then it is broken along the scribe line, but it is not limited to this. The cutting method of the cutting device may be, for example, laser cutting or laser melting.

[0048] Glass plate G is a glass base plate (mother glass plate) from which one or more product glass plates are cut. The thickness of the product glass plate is, for example, 0.2 mm to 2 mm, and the size of the product glass plate is, for example, 700 mm x 700 mm to 3500 mm x 3500 mm. The product glass plate is used, for example, as a substrate or cover glass for a display.

[0049] The following describes a method for manufacturing glass ribbons Gr and glass plates G as glass articles using the manufacturing apparatus 1 with the above configuration. As shown in Figure 5, this method comprises a molding step S1, a slow cooling step S2, a cooling step S3, and a cutting step S4.

[0050] In molding process S1, molten glass Gm is supplied to the first end 9a of the groove 9 of the molded body 6 through the supply pipe 11. The molten glass Gm supplied to the groove 9 overflows from the groove 9 in two directions and flows out to the pair of outer surfaces 6b via the pair of top surfaces 10. The molten glass Gm flows downward along the pair of vertical surfaces 12 on the outer surfaces 6b. Restricting members (not shown) that guide the molten glass Gm are placed at both ends of the molded body 6 in the longitudinal direction (width direction X). These restricting members ensure that the width of the molten glass Gm overflowing from the groove 9 and flowing along the outer surfaces of the molded body 6 remains constant.

[0051] Subsequently, the molten glass Gm moves from the pair of vertical surfaces 12 to the pair of inclined surfaces 13 and flows further downward. The molten glass Gm flows downward along the upper part 13a of the pair of inclined surfaces 13, and then along the lower part 13b toward the lower end 6c. The molten glass Gm flowing along the pair of inclined surfaces 13 merges and becomes one at the lower end 6c of the molded body 6. The integrated molten glass Gm flows downward from the lower end 6c of the molded body 6.

[0052] As a result, the molded body 6 continuously forms a strip-shaped glass ribbon Gr from molten glass Gm. The first conveying roller 8 conveys the glass ribbon Gr downward while gripping the ends of the glass ribbon Gr in the width direction X so that the glass ribbon Gr maintains a constant width.

[0053] Next, in the annealing process S2, the glass ribbon Gr is slowly cooled in the annealing furnace 3 while being conveyed by the second conveyor roller 14. In the subsequent cooling process S3, the glass ribbon Gr is cooled to near room temperature in the cooling chamber 4 while being conveyed by the third conveyor roller 15.

[0054] Subsequently, in cutting step S4, the glass ribbon Gr is cut in the cutting chamber 5 to obtain a glass plate G. Cutting step S4 includes a first cutting step of cutting the glass ribbon Gr into predetermined lengths in the width direction X to obtain a glass plate G, and a second cutting step of cutting and removing the edges at both ends of the glass plate G in the width direction X.

[0055] The post-molding process S1 is not particularly limited. For example, this method may further include a washing process, an inspection process, a packaging process, etc. Alternatively, instead of the cutting process S4, a glass roll may be manufactured by winding the glass ribbon Gr into a roll shape.

[0056] According to the manufacturing method of the molded body 6 and glass article of this embodiment described above, the depth of the groove 9 can be made as large as possible by forming a part 9d1 of the bottom surface 9d of the groove 9 of the molded body 6 below the upper edge 13a1 of the inclined surface 13. As a result, even if the temperature of the molten glass Gm supplied to the groove 9 is lowered in the molding process S1, the molten glass Gm can be uniformly discharged from the groove 9. Therefore, since the temperature of the molded body 6 in the molding process S1 is lowered, creep deformation of the molded body 6 can be suppressed as much as possible. Moreover, since this embodiment changes the shape of the groove 9, which is the internal structure of the molded body 6, it does not lead to an increase in the size of the molded body 6.

[0057] In this embodiment, compared to a conventional molded body 6 in which the depth of the groove 9 is the same, that is, a molded body 6 in which the entire bottom surface 9d of the groove 9 is located above the upper edge 13a1 of the inclined surface 13, the temperature of the molten glass Gm supplied into the groove 9 can be reduced to a range of 10°C to 70°C.

[0058] Furthermore, the present invention is not limited to the configuration of the above embodiments, nor is it limited to the effects described above. The present invention can be modified in various ways without departing from the spirit of the invention.

[0059] In the above embodiment, a molded body 6 in which the upper part 13a of the inclined surface portion 13 is configured in a curved shape was illustrated, but the present invention is not limited to this configuration. The inclined surface portion 13 of the molded body 6 may also be configured such that the inclined surface of the lower part 13b is extended up to the upper part 13a, without the upper part 13a being configured in a curved shape. [Explanation of Symbols]

[0060] 6. Molded body 6b Outer surface of the molded body 6c Lower end of the molded body 9 Grooves of the molded body 9a First end of groove 9b Second end of groove 9c Side of the groove 9d Bottom surface of the groove 9e Chamfered part of the groove 12 Vertical surface portion of the molded body 13 Inclined surface portion of the molded body 13a Upper part of the inclined surface 13a1 Upper edge of the inclined surface G Glass plate (glassware) Gm molten glass Gr Glass Ribbon S1 Molding process

Claims

1. A long molded body formed by shaping glass ribbons from molten glass using the overflow method, The molded body has a groove formed on its upper part, a pair of outer surfaces that allow the molten glass overflowing from the groove to flow downward, and a lower end that allows the molten glass flowing on the pair of outer surfaces to merge. The groove portion has an inner surface and a bottom surface. The pair of outer surfaces of the molded body have a pair of vertical surfaces and a pair of inclined surfaces that are connected below the vertical surfaces. The lower end of the molded body is formed by the intersection of the lower edges of the pair of inclined surfaces. A molded body characterized in that at least a portion of the bottom surface of the groove is located below the upper edge of the inclined surface.

2. The groove portion is configured to be elongated along the longitudinal direction of the molded body. The groove has a first end to which the molten glass is supplied, and a second end located on the opposite side of the first end in the longitudinal direction of the groove. The molded body according to claim 1, wherein at least a portion of the bottom surface of the groove is located on the first end side.

3. The groove portion has a chamfered portion connecting the inner surface and the bottom surface. The molded article according to claim 1 or 2, wherein the chamfered portion is configured to be curved or flat.

4. The upper part of the inclined surface is connected to the vertical surface, The molded body according to claim 1 or 2, wherein the upper part of the inclined surface is configured to be curved.

5. A method for manufacturing a glass article using a molded body according to claim 1 or 2, A method for manufacturing a glass article, comprising a molding step of allowing the molten glass overflowing from the groove of the molded body to flow along the pair of outer surfaces of the molded body, and converging the molten glass flowing along the pair of outer surfaces at the lower end of the molded body.

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