Method and apparatus for manufacturing glass articles

Abstract

The present method includes: a forming step for forming a glass ribbon GR from molten glass GM using a down-draw method; and a cooling step for bringing the glass ribbon GR into contact with a roller part 14 of a cooling roller 12. The roller part 14 of the cooling roller 12 comprises: first cooling sections 16 that come into contact with end sections GRc of the glass ribbon GR in the width direction; and a second cooling section 17 that comes into contact with a central section GRd of the glass ribbon GR in the width direction. The first cooling sections 16 have an uneven surface profile.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for manufacturing glass articles such as glass ribbons. [Background technology]

[0002] Glass plates are used as substrates and covers in displays such as liquid crystal displays and organic EL displays, as well as in organic EL lighting. The overflow downdraw method is a well-known method for manufacturing these glass plates.

[0003] The overflow downdraw method involves pouring molten glass into an overflow groove located at the top of a molded body with a roughly wedge-shaped cross-section. The molten glass that flows out of the overflow groove on both sides is then allowed to flow down along the two sides of the molded body, and these molten glass pieces are fused together at the bottom of the molded body to continuously form a single glass ribbon.

[0004] The glass ribbon formed in this way is transported by a conveyor roller positioned below the molded body, under appropriate tension. This allows for control of the thickness of the glass ribbon.

[0005] In the above manufacturing method, the viscosity of the molten glass supplied to the molded body must be relatively high in order to impart appropriate tension to the glass ribbon. If the viscosity of the molten glass is low, it is not possible to impart appropriate tension to the glass ribbon, and combined with the effect of gravity, it becomes impossible to control the thickness of the glass ribbon.

[0006] To prevent such a situation, for example, the glass plate manufacturing method disclosed in Patent Document 1 uses a roller (forming roller) positioned below the molded body (isopipe). In this method, the viscosity of the glass ribbon (glass flow) formed by the molded body can be increased by bringing it into contact with the roller and cooling it (see paragraph 0120 of the same document). Furthermore, in this manufacturing method, the adhesive force acting between the roller and the glass ribbon prevents the glass ribbon from slipping against the roller (see claim 1 of the same document). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2011-505322 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In the conventional manufacturing method described above, the viscosity of the glass ribbon can be controlled by bringing the glass ribbon, which has been formed by the molded body, into contact with a roller.

[0009] However, in the method described in Patent Document 1, the adhesive force acting on the contact portion (interface) between the roller and the glass ribbon is insufficient, and slippage may occur between the glass ribbon and the roller. In this case, scratches may occur on the glass ribbon, the desired cooling effect may not be obtained, and molding defects may occur.

[0010] This invention has been made in view of the above circumstances, and its technical objective is to suppress slippage between the glass ribbon and the roller. [Means for solving the problem]

[0011] The present invention is for solving the above problems and is a method for manufacturing a glass article comprising a molding step of forming a glass ribbon from molten glass by a down-draw method, and a cooling step of bringing the glass ribbon into contact with the roller portion of a cooling roller, wherein the roller portion of the cooling roller comprises a first cooling portion that contacts the end of the glass ribbon in the width direction, and a second cooling portion that contacts the central portion of the glass ribbon in the width direction, and the first cooling portion has an uneven shape.

[0012] With this configuration, by making the first cooling portion of the roller part of the cooling roller have an uneven shape, a frictional force can be applied between the first cooling portion and the end of the glass ribbon in the width direction that is in contact with the first cooling portion. This frictional force makes it possible to suppress slippage between the glass ribbon and the cooling roller.

[0013] The surface properties of the first cooling section may be rough, and the uneven shape may be composed of the irregularities contained in the rough surface. This allows a frictional force capable of suppressing slippage to be applied between the end of the glass ribbon and the first cooling section (interface).

[0014] The surface of the first cooling section is a processed surface obtained by machining or rolling, and the uneven shape may be composed of the irregularities contained in the processed surface. This allows a frictional force capable of suppressing slippage to be applied between the end of the glass ribbon and the first cooling section (interface).

[0015] In the cooling process, the end of the glass ribbon in the width direction may be clamped between the first cooling portion of the cooling roller and the guide roller. This makes it possible to more effectively suppress slippage between the glass ribbon and the cooling roller.

[0016] The guide roller may have a cooling mechanism. This prevents the glass ribbon from becoming stuck to the guide roller by wrapping around it.

[0017] The guide roller has a roller portion that contacts the glass ribbon, and the roller portion may have an uneven shape. Thereby, it is possible to prevent the glass ribbon from being fixed by winding around the guide roller.

[0018] This method includes a conveying step of conveying the glass ribbon by a conveying roller disposed below the cooling roller. In the conveying step, the glass ribbon sent vertically downward from the cooling roller may be conveyed vertically downward by the conveying roller. Thereby, it is difficult for the glass ribbon being conveyed to be deflected.

[0019] In this method, the liquid-phase viscosity of the molten glass may be 4.5 10 dPa·s or less. Such molten glass with a low liquid-phase viscosity is difficult to be formed by overflow forming without using a cooling roller, but according to the present invention, it can be formed into a high-quality glass ribbon.

[0020] Also, the viscosity of the molten glass at 1000°C may be 7.0 10 dPa·s or more. The glass ribbon formed from such highly viscous molten glass has low wettability and is difficult to adhere to the cooling roller, so slippage is likely to occur between the glass ribbon and the cooling roller. Therefore, the effect of suppressing slippage according to the present invention becomes remarkable.

[0021] The present invention is for solving the above problems, and is a manufacturing apparatus for a glass article including a molding body for molding a glass ribbon from molten glass by the down-draw method and a cooling roller for cooling the glass ribbon. The cooling roller includes a roller portion that contacts the glass ribbon. The roller portion includes a first cooling portion that contacts an end portion in the width direction of the glass ribbon and a second cooling portion that contacts a central portion in the width direction of the glass ribbon, and the first cooling portion has an uneven shape.

[0022] With this configuration, by making the first cooling portion of the roller part of the cooling roller have an uneven shape, a frictional force can be applied between the first cooling portion and the end of the glass ribbon in the width direction that is in contact with the first cooling portion. This frictional force makes it possible to suppress slippage between the glass ribbon and the cooling roller. [Effects of the Invention]

[0023] According to the present invention, slippage between the glass ribbon and the roller can be suppressed. [Brief explanation of the drawing]

[0024] [Figure 1] This is a front view showing a method for manufacturing a glass article according to the first embodiment. [Figure 2] This is a cross-sectional view along the line of arrow II-II in Figure 1. [Figure 3] This is a front view of the cooling roller. [Figure 4] This is a cross-sectional view of the guide roller. [Figure 5] This is a front view showing a method for manufacturing a glass article according to the second embodiment. [Figure 6] This is a cross-sectional view of the line of sight from arrow VI-VI in Figure 5. [Figure 7] This is a cross-sectional view showing a method for manufacturing a glass article according to the third embodiment. [Figure 8] This is a cross-sectional view showing a method for manufacturing a glass article according to the fourth embodiment. [Modes for carrying out the invention]

[0025] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Figures 1 to 4 show a first embodiment of the method for manufacturing a glass article according to the present invention.

[0026] Figures 1 and 2 show the manufacturing apparatus for glass articles used in this method. The manufacturing apparatus 1 mainly comprises a molding area 2, a cooling area 3 located below the molding area 2, and a slow-cooling area 4 located below the cooling area 3.

[0027] The molding region 2 comprises a molded body 5 for forming a glass ribbon GR from molten glass GM. The molded body 5 is made of refractory bricks such as dense zircon, alumina, or zirconia. The molded body 5 may be coated with a precious metal (e.g., platinum or a platinum alloy). The precious metal coating can be formed, for example, by thermal spraying. The precious metal coating may be formed on the entire surface of the molded body 5, or only on the portion in contact with the molten glass GM.

[0028] The molded body 5 is configured in an elongated shape and has an overflow groove 6 formed along its longitudinal direction at its top. The molded body 5 also includes a pair of side surfaces 7 and guide portions 8 that guide (restrict) the ends in the width direction of the molten glass GM downward.

[0029] Each side surface 7 includes an upper vertical surface portion 9 and a lower inclined surface portion 10. As shown in Figure 2, the pair of vertical surface portions 9 relating to the pair of side surfaces 7 are formed to align with the vertical direction. The pair of inclined surface portions 10 are inclined downward so as to approach each other. The lower ends of each inclined surface portion 10 are connected, thereby forming the lower end portion 11 of the molded body 5.

[0030] In the molded body 5, the molten glass GM that overflows from the overflow groove 6 on both sides flows down along each side 7 and is formed into a plate shape. The plate-shaped molten glass GM flowing down each side 7 fuses together at the lower end 11, and a single glass ribbon GR is continuously formed. The glass ribbon GR includes a first main surface GRa and a second main surface GRb located on the opposite side of the first main surface GRa.

[0031] Furthermore, as shown in Figures 1 and 3, the glass ribbon GR includes each end GRc in the width direction X and a central part GRd in the width direction X. The end GRc of the glass ribbon GR is the part that is cut off from the central part GRd in a later process and discarded. The central part GRd of the glass ribbon GR is the part that can become a product after the end GRc is removed.

[0032] As the glass, silicate glass is used, preferably borosilicate glass, soda-lime glass, alkali aluminosilicate glass, LAS-type glass, or alkali-free glass. If alkali aluminosilicate glass is used, it becomes suitable for display covers by applying a chemical strengthening treatment in a later process. If LAS-type glass is used, it becomes suitable for heat-resistant crystallized glass by applying a crystallization treatment in a later process. If alkali-free glass is used, it becomes suitable for display substrates. Here, alkali-free glass is glass that does not substantially contain alkali components (alkali metal oxides), and specifically, it is glass in which the weight ratio of alkali components is 3000 ppm or less. The weight ratio of alkali components is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less.

[0033] The thickness of the glass ribbon GR is, for example, 400 to 1200 μm. The width of the glass ribbon GR is, for example, 400 to 2000 mm.

[0034] The cooling region 3 includes a cooling roller 12 that contacts the glass ribbon GR formed by the molded body 5, and a guide roller 13 that holds the glass ribbon GR together with the cooling roller 12.

[0035] The cooling roller 12 is positioned below the molded body 5. The vertical distance D between the cooling roller 12 and the lower end portion 11 of the molded body 5 is, for example, 50 to 150 mm. The cooling roller 12 is made of metal, and is cylindrically constructed from, for example, heat-resistant steel. The cooling roller 12 has a cooling mechanism (not shown) inside. The cooling mechanism cools the cooling roller 12 by supplying a cooling medium to the inside of the cooling roller 12.

[0036] The cooling roller 12 has a roller portion 14 and a shaft portion 15 that supports the roller portion 14.

[0037] The roller section 14 has a length dimension greater than the width dimension of the glass ribbon GR. The diameter of the roller section 14 is, for example, 100 to 1500 mm.

[0038] The roller portion 14 has a first cooling portion 16 that contacts the end portion GRc of the glass ribbon GR in the width direction X, and a second cooling portion 17 that contacts the central portion GRd of the glass ribbon GR in the width direction X. The first cooling portion 16 and the second cooling portion 17 are provided on the outer circumferential surface (surface) of the roller portion 14.

[0039] The first cooling section 16 has an uneven surface and is a surface (contact surface) that contacts the end GRc of the glass ribbon GR from the second main surface GRb side. The uneven surface of the first cooling section 16 is composed of a rough surface with a surface roughness Ra (arithmetic mean roughness according to JIS B 0601-2001) of 100 μm or more, more preferably 200 to 400 μm. In other words, the uneven surface of the first cooling section 16 is composed of the irregularities contained in this rough surface. In this case, the uneven surface of the first cooling section 16 is formed, for example, by blasting the first cooling section 16.

[0040] The uneven shape of the first cooling section 16 can be formed by machining or rolling its outer surface, not limited to the examples above. Examples of these machined surfaces include knurled surfaces, spiral grooves formed by threading, and grooves formed by grooving. The grooves formed by grooving may extend in the longitudinal direction of the roller section 14 or in the circumferential direction of the roller section 14.

[0041] In these cases, the surface of the first cooling section 16 becomes a machined surface by machining or rolling, and the uneven shape of the first cooling section 16 is composed of the irregularities contained in the machined surface. In this case, the first cooling section 16 will have an uneven shape (uneven surface) with greater undulations compared to the case where blasting is performed. When a knurled surface is used, the machined surface can be formed by flat knurling and diagonal knurling as specified in JIS B0951:1962, for example. In this case, the pitch of the grooves on the knurled surface is preferably 0.5 mm or more and 1.6 mm or less, and the depth of the grooves is preferably 0.5 mm or more and 1.0 mm or less.

[0042] The second cooling section 17 is formed, for example, by a smooth surface. The second cooling section 17 is formed, for example, by grinding and polishing. The second cooling section 17 contacts the central portion GRd of the glass ribbon GR in the width direction X from the second main surface GRb side.

[0043] The shaft portion 15 is provided at each end of the roller portion 14 in the longitudinal direction. The shaft portion 15 is rotationally driven by a drive mechanism (not shown).

[0044] As shown in Figures 1 and 4, the guide roller 13 comprises a roller portion 18, a shaft portion 19 that supports the roller portion 18, and a cooling mechanism 20.

[0045] The roller portion 18 is made of, for example, metal (more specifically, heat-resistant steel). The outer surface (surface) of the roller portion 18 has an uneven shape and is a contact surface that comes into contact with the glass ribbon GR.

[0046] As shown in Figures 1 and 4, the uneven shape of the roller portion 18 is composed of a single groove 21 formed continuously (annularly) along the circumferential direction of the roller portion 18 and the outer circumferential surface of the roller portion 18 excluding the groove 21.

[0047] The width dimension W of the groove 21 is, for example, 1.5 to 5.0 mm. The depth dimension DP of the groove 21 is, for example, 0.5 to 2.0 mm.

[0048] Not limited to the above example, the outer circumferential surface of the roller portion 18 may have multiple grooves or one or more protrusions. Furthermore, not limited to the above example, the outer circumferential surface of the roller portion 18 may be a rough surface having an uneven shape with a surface roughness Ra of 100 μm or more, preferably 200 to 400 μm, without having grooves 21. In this case, the uneven shape of the roller portion 18 will be composed of the irregularities contained in this rough surface. Alternatively, the outer circumferential surface of the roller portion 18 may have an uneven shape (knurled surface) formed by knurling. In this case, the uneven shape of the outer circumferential surface of the roller portion 18 will be composed of the irregularities contained in the knurled surface.

[0049] As shown in Figure 4, the shaft portion 19 is hollow. The shaft portion 19 is rotationally driven by a drive device (not shown).

[0050] As shown in Figure 4, the cooling mechanism 20 includes a cooling pipe 22 provided inside the hollow shaft portion 19. The cooling pipe 22 has an opening 23 for discharging a cooling medium such as air. The cooling medium discharged from the opening 23 cools the shaft portion 19 and the roller portion 18 by circulating inside the shaft portion 19 as indicated by the arrows in Figure 4.

[0051] As shown in Figure 2, the vertical position (height) of the axis O2 of the guide roller 13 is the same as the vertical position (height) of the axis O1 of the cooling roller 12. In other words, the axis O1 of the cooling roller 12 and the axis O2 of the guide roller 13 are located on the same horizontal line HL.

[0052] As shown in Figures 1 and 2, the slow-cooling region 4 is equipped with multiple upper and lower transport rollers 24 that transport the glass ribbon GR downward. The transport rollers 24 are positioned below the cooling rollers 12 and the guide rollers 13. Each upper and lower transport roller 24 consists of a pair of rollers that grip the end portion GRc of the glass ribbon GR in the width direction X between the first main surface GRa side and the second main surface GRb side.

[0053] Each conveying roller 24 has a roller portion 25 and a shaft portion 26. The roller portion 25 is made of, for example, ceramics. The roller portion 25 has a surface (contact surface) that contacts the end GRc of the glass ribbon GR in the width direction X. The shaft portion 26 is rotationally driven by a drive device (not shown).

[0054] In addition to the above, the annealing region 4 is equipped with heaters (not shown) arranged along the transport path of the glass ribbon GR. In the annealing region 4, these heaters create a predetermined temperature gradient along the transport path of the glass ribbon GR.

[0055] The following describes a method for manufacturing glass articles using the manufacturing apparatus 1 with the above configuration.

[0056] This method mainly includes a forming step of forming a glass ribbon GR from molten glass GM by an overflow downdraw method, a cooling step of bringing the glass ribbon GR into contact with the roller portion 14 of a cooling roller 12, and a slow cooling step of slowly cooling the glass ribbon GR that has passed through the cooling roller 12.

[0057] In the molding process, in the molding region 2, molten glass GM is allowed to overflow from the overflow groove 6 of the molded body 5 and flow downward through both sides 7 of the molded body 5 to form a plate. This plate-shaped molten glass GM is fused at the lower end 11 of the molded body 5 to form a glass ribbon GR. The molded body 5 can form a glass ribbon GR of a constant width by regulating the end of the molten glass GM with the guide portion 8. The temperature of the glass ribbon GR before it leaves the lower end 11 and comes into contact with the cooling roller 12 is, for example, 1000 to 1450°C. Also, the viscosity of the glass ribbon GR in this case is 10 2.0 ~10 5.5 The viscosity is dPa·s. When the glass ribbon GR is made of molten glass with low liquid-phase viscosity, the viscosity is 10 2.0 ~10 4.5 The viscosity becomes dPa·s. If the glass ribbon GR is made of high-viscosity molten glass, the viscosity mentioned above is, for example, 10 2.0 ~10 5.5It becomes dPa·s, preferably 10 4.5 ~ 10 5.5 dPa·s.

[0058] The liquid-phase viscosity of the molten glass GM is 10 2 dPa·s or more and 10 4.5 dPa·s or less is preferable. Here, the "liquid-phase viscosity" refers to the viscosity of the glass at the liquid-phase temperature and can be measured by the platinum ball pulling-up method. Also, the viscosity of the molten glass GM at 1000 °C can be 10 4.5 dPa·s or more, and preferably 10 7.0 dPa·s or more. On the other hand, the upper limit of the viscosity of the molten glass GM at 1000 °C is preferably 10 7.6 dPa·s or less from the viewpoint of preventing crack generation.

[0059] In the cooling step, the second main surface GRb of the glass ribbon GR separated from the lower end portion 11 of the molded body 5 is brought into contact with the roller portion 14 of the cooling roller 12 in the cooling region 3. At this time, the first cooling portion 16 of the roller portion 14 of the cooling roller 12 contacts the end portion GRc of the glass ribbon GR, and the second cooling portion 17 of the roller portion 14 of the cooling roller 12 contacts the central portion GRd of the glass ribbon GR. By contacting the cooling roller 12, the temperature of the glass ribbon GR becomes, for example, 650 to 1000 °C. Also, the viscosity of the glass ribbon GR becomes, for example, 10 7.0 ~ 10 9.9 dPa·s, and preferably 10 7.6 ~ 10 9.9 dPa·s.

[0060] In the cooling step, the guide roller 13 contacts the end portion GRc of the glass ribbon GR from the first main surface GRa side. Thereby, the end portion GRc of the glass ribbon GR is sandwiched between the first cooling portion 16 of the cooling roller 12 and the guide roller 13. The cooling roller 12 and the guide roller 13 guide the glass ribbon GR vertically downward while rotating.

[0061] In the subsequent annealing process, the glass ribbon GR passes through the annealing region 4 by being transported by the transport roller 24 (transportation process). In the transport process, the glass ribbon GR, which is fed vertically downward from the cooling roller 12, is transported vertically downward by the transport roller 24. However, by changing the horizontal position of the transport roller 24, it is also possible to transport the glass ribbon GR at an inclination relative to the vertical direction.

[0062] Subsequently, various processes such as cutting may be carried out. For example, in the cutting process, a rectangular glass plate is obtained by cutting the middle part of the glass ribbon GR along the width direction X. After that, for example, after removing the portion corresponding to the end GRc of the glass ribbon GR from the glass plate, the glass plate is manufactured as a glass article through a quality inspection of the glass plate surface (inspection process), grinding and polishing of the edges of the glass plate (grinding and polishing process), and cleaning of the glass plate surface (cleaning process).

[0063] In addition to the above steps, this method may also include a winding step in which the end portion GRc is removed and the glass ribbon GR, which consists only of the central portion GRd, is wound into a roll. This produces a glass roll as a glass article.

[0064] As described above, in the manufacturing method for glass articles according to this embodiment, by making the first cooling portion 16 of the roller portion 14 of the cooling roller 12 have an uneven shape, a frictional force is applied between the first cooling portion 16 and the end portion GRc of the glass ribbon GR that is in contact with it during the cooling process, thereby suppressing slippage between the end portion GRc of the glass ribbon GR and the first cooling portion 16. This also suppresses slippage between the central portion GRd of the glass ribbon GR and the second cooling portion 17, making it possible to produce a high-quality central portion GRd of the glass ribbon GR as a finished product.

[0065] Furthermore, in the cooling process, by clamping the end portion GRc of the glass ribbon GR between the first cooling portion 16 of the cooling roller 12 and the guide roller 13, in addition to the slip suppression effect described above, it is possible to suppress the shrinkage of the glass ribbon GR in the width direction X due to the cooling of the cooling roller 12.

[0066] Furthermore, by providing the guide roller 13 with an uneven shape including grooves 21, it is possible to apply a greater frictional force between the roller portion 18 of the guide roller 13 and the end portion GRc of the glass ribbon GR. By providing the guide roller 13 with a cooling mechanism 20, it is possible to prevent the high-temperature glass ribbon GR from sticking to the guide roller 13 due to wrapping around it.

[0067] Figures 5 and 6 show a second embodiment of the present invention. The cooling region 3 of the manufacturing apparatus 1 according to this embodiment includes edge rollers 27 located below the cooling rollers 12. As shown in Figure 5, the edge rollers 27 are paired left and right to grip a pair of edges GRe included in the end portion GRc in the width direction X of the glass ribbon GR. Also, as shown in Figure 6, each edge roller 27 includes two rollers that clamp the glass ribbon GR.

[0068] Each edge roller 27 comprises a roller portion 28 and a shaft portion 29. The roller portion 28 is made of a heat-resistant material such as ceramics or metal. The shaft portion 29 is rotationally driven by a drive source such as a motor. Each edge roller 27 has a cooling mechanism (not shown) inside, similar to the guide roller 13 of the first embodiment. The edge roller 27 is configured to be movable along its axial direction.

[0069] During the cooling process, the edge roller 27 grips (cools) the edge portion GRe of the glass ribbon GR that has passed through the cooling roller 12, thereby suppressing shrinkage in the width direction X of the glass ribbon GR and forming the glass ribbon GR to a constant width.

[0070] Other configurations in this embodiment are the same as those in the first embodiment. In this embodiment, components common to the first embodiment are denoted by the same reference numerals.

[0071] Figure 7 shows a third embodiment of the present invention. In this embodiment, the configuration of the molded body 5 and the molding process differs from that of the first embodiment. The molded body 5 includes one side surface 7 that guides the molten glass GM that has flowed out from the overflow groove 6 downward, and a guide portion 8 that guides (restricts) the end of the molten glass GM in the width direction downward.

[0072] The side surface 7 of the molded body 5 is composed only of a vertical surface portion 9 extending in the vertical direction, but the shape of the side surface 7 is not limited to this embodiment. The side surface 7 may be a surface inclined with respect to the vertical direction, or it may be a surface formed by a combination of the vertical surface portion 9 and the inclined surface portion.

[0073] In this embodiment, in the molding process, instead of fusing the molten glass GM at the lower end 11 of the molded body 5 with a pair of side surfaces 7 as in the first embodiment, the glass ribbon GR can be formed from the molten glass GM with only one side surface 7. The glass ribbon GR has a first main surface GRa and a second main surface GRb formed when the molten glass GM comes into contact with the side surface 7. In the cooling process, the cooling roller 12 comes into contact with the end surface GRc of the glass ribbon GR from the second main surface GRb side.

[0074] Other configurations in this embodiment are the same as those in the first embodiment. In this embodiment, components common to the first embodiment are denoted by the same reference numerals.

[0075] Figure 8 shows a fourth embodiment of the present invention. The molded body 5 of the manufacturing apparatus 1 according to this embodiment has two sides 7, but each side 7 is composed only of a vertical surface portion 9. The lower ends 11 of the two vertical surface portions 9 are not connected, and each side 7 can independently form a single glass ribbon GR1, GR2. That is, in the manufacturing method of the glass article according to this embodiment, in the molding process, the plate-shaped molten glass GM flowing on one side 7 and the plate-shaped molten glass GM flowing on the other side 7 do not fuse at the respective lower ends 11 of the molded body 5.

[0076] Hereinafter, the glass ribbon formed by one of the two sides 7 will be referred to as the first glass ribbon GR1, and the glass ribbon formed by the other side 7 will be referred to as the second glass ribbon GR2.

[0077] The cooling area 3 of the manufacturing apparatus 1 includes a first cooling roller 12a and a first guide roller 13a that contact the first glass ribbon GR1, and a second cooling roller 12b and a second guide roller 13b that contact the second glass ribbon GR2. Each cooling roller 12a, 12b has the same configuration as the cooling roller 12 of the first embodiment. Each guide roller 13a, 13b has the same configuration as the guide roller 13 of the first embodiment.

[0078] The slow-cooling region 4 of the manufacturing apparatus 1 includes a first conveyor roller 24a for conveying the first glass ribbon GR1 and a second conveyor roller 24b for conveying the second glass ribbon GR2. Each conveyor roller 24a, 24b has the same configuration as the conveyor roller 24 of the first embodiment.

[0079] In the manufacturing method of the glass article according to this embodiment, during the molding process, the molten glass GM that overflows from the overflow groove 6 is allowed to flow down along the two side surfaces 7, thereby simultaneously molding two glass ribbons GR1 and GR2.

[0080] In the subsequent cooling process, the first glass ribbon GR1 and the second glass ribbon GR2 are cooled simultaneously by the cooling rollers 12a, 12b and the guide rollers 13a, 13b. Similarly, in the slow cooling process (conveying process), the glass ribbons GR1 and GR2 are conveyed simultaneously by the conveying rollers 24a, 24b.

[0081] Other configurations in this embodiment are the same as those in the first embodiment. In this embodiment, components common to the first embodiment are denoted by the same reference numerals.

[0082] 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.

[0083] In the above embodiment, an example was shown in which the end portion GRc of the glass ribbon GR is held between the cooling roller 12 and the guide roller 13 during the cooling process. However, the present invention is not limited to this configuration. In the cooling process, even without using the guide roller 13, simply bringing the end portion GRc of the glass ribbon GR into contact with the uneven shape of the first cooling portion 16 of the cooling roller 12 will suppress slippage between the glass ribbon GR and the cooling roller 12 due to the frictional force.

[0084] In the above embodiment, the glass ribbon GR was formed from molten glass GM by the overflow downdraw method, but the glass ribbon GR may also be formed from molten glass GM by the slit downdraw method. [Explanation of Symbols]

[0085] 1. Apparatus for manufacturing glass articles 12 Cooling rollers 12a First cooling roller 12b Second cooling roller 13 Guide rollers 13a First guide roller 13b Second guide roller 14. Roller section of the cooling roller 16 First cooling section 17 Second cooling section 18 Roller section of guide roller 20 Cooling mechanism 24 Conveyor rollers 24a First conveyor roller 24b Second conveyor roller GM molten glass GR Glass Ribbon GR1 First Glass Ribbon GR2 Second Glass Ribbon End of GRc glass ribbon in the width direction GRd glass ribbon, central part in the width direction X Glass ribbon width direction

Claims

1. A method for manufacturing a glass article, comprising a molding step of forming a glass ribbon from molten glass by a down-draw method, and a cooling step of bringing the glass ribbon into contact with the roller portion of a cooling roller, The roller portion of the cooling roller comprises a first cooling portion that contacts the end of the glass ribbon in the width direction, and a second cooling portion that contacts the central part of the glass ribbon in the width direction. The first cooling section has an uneven shape, A method for manufacturing a glass article, characterized in that the second cooling section is composed of a smooth surface.

2. The surface characteristics of the first cooling section are rough. The method for manufacturing a glass article according to claim 1, wherein the uneven shape is formed by the unevenness contained in the rough surface.

3. The surface of the first cooling section is a machined surface obtained by machining or rolling. The method for manufacturing a glass article according to claim 1, wherein the aforementioned uneven shape is formed by the unevenness included in the processed surface.

4. A method for manufacturing a glass article according to any one of claims 1 to 3, wherein in the cooling step, the end of the glass ribbon in the width direction is clamped by the first cooling portion of the cooling roller and the guide roller.

5. The method for manufacturing a glass article according to claim 4, wherein the guide roller has a cooling mechanism.

6. The guide roller has a roller portion that contacts the glass ribbon, The method for manufacturing a glass article according to claim 4, wherein the roller portion has an uneven shape.

7. The process includes a conveying step in which the glass ribbon is conveyed by a conveying roller positioned below the cooling roller, A method for manufacturing a glass article according to any one of claims 1 to 3, wherein in the conveying step, the glass ribbon that has been fed vertically downward from the cooling roller is conveyed vertically downward by the conveying roller.

8. The liquid phase viscosity of the molten glass is 10 ４．５ A method for manufacturing a glass article according to any one of claims 1 to 3, wherein the pressure is dPa·s or less.

9. The viscosity of the molten glass at 1000°C is 10 ７．０ A method for manufacturing a glass article according to any one of claims 1 to 3, wherein the pressure is dPa·s or higher.

10. A glass article manufacturing apparatus comprising a molded body for forming a glass ribbon from molten glass by a down-draw method, and a cooling roller for cooling the glass ribbon, The cooling roller includes a roller portion that contacts the glass ribbon, The roller portion comprises a first cooling portion that contacts the end of the glass ribbon in the width direction, and a second cooling portion that contacts the central part of the glass ribbon in the width direction. The first cooling section has an uneven shape, The apparatus for manufacturing glass articles is characterized in that the second cooling section is composed of a smooth surface.

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