WO2014185127A1

WO2014185127A1 - Method for molding glass plate, device for manufacturing glass plate, and method for manufacturing glass plate

Info

Publication number: WO2014185127A1
Application number: PCT/JP2014/056036
Authority: WO
Inventors: 海郡司; 信之伴
Original assignee: 旭硝子株式会社
Priority date: 2013-05-16
Filing date: 2014-03-07
Publication date: 2014-11-20
Also published as: JP2016135715A

Abstract

Provided is a method for molding a glass plate that includes a step in which contraction in the width direction of a strip-shaped glass ribbon is minimized, and wherein: a support roller is provided that supports a glass ribbon in an area in which the glass ribbon has a viscosity in the range of 10.^6.7-10^7.65 dPa·s; the support roller comprises a rotating member on the tip section thereof that comes into contact with the glass ribbon; and the rotating member does not comprise a refrigerant flow path in the interior thereof and is formed from ceramic.

Description

Glass plate forming method, glass plate manufacturing apparatus, and glass plate manufacturing method

The present invention relates to a glass plate forming method, a glass plate manufacturing apparatus, and a glass plate manufacturing method.

The float method is widely used as a glass plate forming method. The float method is a method in which molten glass introduced on a molten metal (for example, molten tin) accommodated in a bathtub is caused to flow in a predetermined direction to form a strip-shaped glass ribbon. The glass ribbon is gradually cooled in the process of flowing in the horizontal direction, then pulled up from the molten metal by a lift-out roll, and gradually cooled in a slow cooling furnace to become a sheet glass. The plate glass is unloaded from the slow cooling furnace, and then cut into a predetermined size and shape by a cutting machine to become a product glass plate.

Also, as another molding method, a fusion method is also known. In the fusion method, the molten glass overflowing from the upper edges of the left and right sides of the bowl-shaped member is allowed to flow along the left and right sides of the bowl-shaped member, and is joined at the lower edge where the left and right sides meet. This is a method of making a glass ribbon. The glass ribbon is gradually cooled while moving downward in the vertical direction to form a sheet glass. The plate-like glass is cut into a predetermined dimensional shape by a cutting machine to become a glass plate as a product.

By the way, the glass ribbon in a state thinner than the equilibrium thickness tends to shrink in the width direction. If the glass ribbon shrinks in the width direction, the thickness of the glass plate as a product becomes thicker than the target thickness. This problem becomes more prominent as the target thickness decreases.

Therefore, conventionally, in order to suppress shrinkage in the width direction of the glass ribbon, a support roll for supporting the glass ribbon has been used (for example, see Patent Document 1). A plurality of pairs of support rolls are arranged on both sides of the glass ribbon in the width direction, and tension is applied to the glass ribbon in the width direction. The support roll has a rotating member in contact with the surface of the glass ribbon at the tip. As the rotating member rotates, the glass ribbon is sent out in a predetermined direction. The glass ribbon is gradually cooled and hardened while moving in a predetermined direction.

The rotating member of the support roll is formed in a disk shape with a metal material such as steel or a heat-resistant alloy, and a chromium plating layer or the like may be applied to the portion of the rotating member that contacts the glass ribbon. The rotating member has gear-shaped irregularities on the outer peripheral portion in contact with the glass ribbon so that the glass ribbon is easily supported.

JP 2011-225386 A

The support roll is provided in a float bath forming region (for example, a region where the glass ribbon has a viscosity range of 10 ^4.5 to 10 ^7.5 dPa · s). In recent years, glass plates, particularly glass plates for display substrates, are required to have high quality. Moreover, the glass plate for display substrates is also required to be thin (for example, a thickness of 0.5 mm or less).

The conventional rotating member has a refrigerant flow path inside to suppress thermal deformation of the metal. Since the refrigerant flows inside the rotating member, the glass ribbon is strongly cooled and hardened in the vicinity of the rotating member. Therefore, it was difficult to grip the glass ribbon with the rotating member in the low temperature region of the float bath (the region where the glass ribbon has a viscosity range of 10 ^6.7 to 10 ^7.65 dPa · s). For this reason, the glass ribbon may shrink in the width direction, and a wavy deformation may occur in the glass ribbon.

This invention was made in view of the said subject, Comprising: It aims at provision of the shaping | molding method of a glass plate which can improve the wavy deformation | transformation of a glass ribbon.

In order to solve the above problems, according to one aspect of the present invention,
A method for forming a glass plate, comprising a step of suppressing the shrinkage in the width direction of a belt-like glass ribbon,
A support roll for supporting the glass ribbon in a viscosity range of 10 ^6.7 to 10 ^7.65 dPa · s is provided;
The support roll has a rotating member in contact with the glass ribbon at the tip,
There is provided a method for forming a glass plate, in which the rotating member does not have a coolant channel inside and is formed of ceramics.

According to one aspect of the present invention, a glass plate forming method that can improve the wave-like deformation of the glass ribbon can be provided.

1 is a partial cross-sectional view showing a glass sheet forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. It is a front view which shows the support roll by one Embodiment of this invention. FIG. 4 is a partial cross-sectional view taken along line IV-IV in FIG. 3. It is a front view which shows the modification (1) of a rotating member. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a first diagram illustrating dimensions of a convex shape of the rotating member of FIG. 6. FIG. 7 is a second diagram illustrating dimensions of a convex shape of the rotating member of FIG. 6. It is a front view which shows the modification (2) of a rotating member. It is a front view which shows the modification (3) of a rotating member. It is a front view which shows the modification (4) of a rotation member. It is a front view which shows the modification (5) of a rotation member. 6 is a graph showing the change over time of the wettability of molten glass with respect to sintered silicon nitride ceramics according to Examples 1 to 4.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

(Glass plate molding apparatus and molding method)
FIG. 1 is a partial cross-sectional view showing a glass sheet forming apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II in FIG. In FIG. 2, the forming area of the float bath 20 (the glass ribbon G has a viscosity range of 10 ^4.5 to 10 ^7.5 dPa · s) is A, and the first low temperature area of the float bath 20 (the glass ribbon G is 10). ^6.7 to 10 ^7.65 dPa · s) and B ′ is the second low temperature region of the float bath 20 (the glass ribbon G has a viscosity range of more than 10 ^7.5 to 10 ^7.65 dPa · s). It shows with. The molding area A and the first low temperature area B partially overlap. The second low temperature region B ′ is included in the first low temperature region B, but does not overlap with the molding region A.

The glass plate forming apparatus 10 has a float bath 20. The float bath 20 is connected to the bathtub 22 that houses the molten metal (for example, molten tin) S, the side wall 24 that is installed along the outer peripheral upper edge of the bathtub 22, and the ceiling 26 that covers the upper side of the bathtub 22. Etc. The ceiling 26 is provided with a gas supply path 30 for supplying a reducing gas in a space 28 formed between the bathtub 22 and the ceiling 26. Further, a heater 32 as a heating source is inserted into the gas supply path 30, and a heat generating part 32 a of the heater 32 is disposed above the molten tin S and the glass ribbon G.

The forming method using the forming apparatus 10 is a method for forming a ribbon glass ribbon G by causing molten glass introduced on a molten metal (for example, molten tin) S to flow in a predetermined direction. The glass ribbon G is cooled in the process of flowing in a predetermined direction (X direction in FIG. 2), then pulled up from the molten tin S by a lift-out roll, and gradually cooled in a slow cooling furnace to become a sheet glass. The plate-like glass is unloaded from the slow cooling furnace and then cut into a predetermined size and shape by a cutting machine to become a glass plate as a product.

The space 28 in the float bath 20 is filled with a reducing gas supplied from the gas supply path 30 in order to prevent the molten tin S from being oxidized. The reducing gas contains, for example, 1 to 15% by volume of hydrogen gas and 85 to 99% by volume of nitrogen gas. The space 28 in the float bath 20 is set to a pressure higher than the atmospheric pressure in order to prevent air from entering through the gaps between the side walls 24 and the like.

In order to adjust the temperature distribution in the float bath 20, a plurality of heaters 32 are provided at intervals in the flow direction (X direction) and the width direction (Y direction) of the glass ribbon G, for example, and arranged in a matrix. Yes. The output of the heater 32 is controlled so that the temperature of the glass ribbon G becomes higher toward the upstream side in the flow direction (X direction) of the glass ribbon G. The output of the heater 32 is controlled so that the thickness of the glass ribbon G is uniform in the width direction (Y direction).

Also, the glass plate forming apparatus 10 includes a support roll 40 that supports the glass ribbon G in order to suppress the glass ribbon G in the float bath 20 from shrinking in the width direction. As shown in FIG. 2, a plurality of pairs of support rolls 40 are arranged on both sides in the width direction of the glass ribbon G, and tension is applied to the glass ribbon G in the width direction (Y direction in the figure).

The support roll 40 has a rotating member 50 in contact with the glass ribbon G at the tip. The rotating member 50 supports the end of the glass ribbon G in the width direction so that the glass ribbon G does not contract in the width direction by biting into or contacting the upper surface of the glass ribbon G. As the rotating member 50 rotates, the glass ribbon G is sent out in a predetermined direction.

(Support roll)
FIG. 3 is a front view showing a support roll according to an embodiment of the present invention. 4 is a partial cross-sectional view taken along line IV-IV in FIG.

The support roll 40 is mainly composed of a rotating member 50, an attaching member 60 to which the rotating member 50 is attached, and a shaft member 70 integrated with the attaching member 60. Hereinafter, although the structure of the rotation member 50, the attachment member 60, and the shaft member 70 is demonstrated, it demonstrates in order of the shaft member 70, the attachment member 60, and the rotation member 50 for convenience of explanation.

(Shaft member)
The shaft member 70 has a coolant channel inside, is cooled by the coolant flowing through the coolant channel, and may be formed of a metal material such as steel or a heat-resistant alloy. A heat insulating material (not shown) or the like may be wound around the outer periphery of the shaft member 70.

The shaft member 70 is, for example, a double pipe, and includes an inner pipe and an outer pipe. A refrigerant flow path is constituted by the inner space of the inner tube and the space formed between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube.

As the refrigerant, a liquid such as water or a gas such as air is used. For example, after the refrigerant passes through the inner space of the inner pipe and is supplied to the inner space of the mounting member 60, the refrigerant passes through the space formed between the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe, Discharged. The refrigerant discharged to the outside may be cooled by a cooler and returned to the inner space of the inner pipe again. Note that the flow direction of the refrigerant may be in the opposite direction.

As shown in FIG. 1, the shaft member 70 passes through the side wall 24, and is connected to a drive device 34 constituted by a motor, a speed reducer, and the like outside the float bath 20. When the driving device 34 is operated, the shaft member 70, the attachment member 60, and the rotation member 50 are integrally rotated around the central axis of the shaft member 70.

(Mounting member)
As shown in FIG. 4, the attachment member 60 is integrated with the shaft member 70, and may have an inner space (not shown) that communicates with the refrigerant flow path of the shaft member 70. Since the coolant flows in the inner space, the attachment member 60 may be formed of a metal material such as steel or a heat-resistant alloy. The rotation member 50 is detachably attached to the attachment member 60.

The attachment member 60 includes a shaft portion 62 that is integrated with the shaft member 70, an annular flange portion 63 that protrudes radially outward from the tip portion of the shaft portion 62, and a tip portion of the shaft portion 62. The shaft portion 62 and the rod portion 64 extending coaxially are integrally provided.

The shaft portion 62 is abutted against the shaft member 70 and integrated by welding, for example. The shaft portion 62 may be provided with a coolant channel (not shown) that communicates with the coolant channel of the shaft member 70.

The flange portion 63 protrudes outward in the radial direction of the shaft portion 62 from the tip end portion (the end portion opposite to the shaft member 70) of the shaft portion 62. The flange portion 63 may be provided with a coolant channel (not shown) that communicates with the coolant channel of the shaft member 70.

The rod portion 64 extends coaxially with the shaft portion 62 from the tip portion of the shaft portion 62. The rod portion 64 may be provided with a coolant channel (not shown) that communicates with the coolant channel of the shaft member 70. As shown in FIG. 4, the rod portion 64 penetrates the rotating member 50 and has a male screw portion at the tip. The movement of the rotating member 50 in the axial direction is restricted by the nut 41 screwed to the male screw portion and the flange portion 63. By removing the nut 41 from the male screw portion, the rotating member 50 can be removed.

The mounting member 60 is fixed to the surface on the tip end side of the flange portion 63 and has

shaft portions

67 and 68 parallel to the central axis of the rod portion 64. The attachment members 60 and the rotation member 50 can be rotated integrally by the

shaft portions

67 and 68 and the rod portion 64.

As shown in FIG. 4, each of the

shaft portions

67 and 68 penetrates the rotating member 50 and has a male screw portion at the tip. The nuts 42 and 43 screwed to the male screw portion and the flange portion 63 restrict the movement of the rotating member 50 in the axial direction. The rotating member 50 can be removed by removing the nuts 42 and 43 from the male screw portion.

(Rotating member)
The rotating member 50 has a disk shape, and the central axis of the rotating member 50 and the central axis of the shaft member 70 are on the same straight line. The rotating member 50 contacts the surface of the glass ribbon G (the upper surface in the present embodiment) at the outer peripheral portion 51. As the rotating member 50 rotates, the glass ribbon G is sent out in a predetermined direction.

Rotating member 50 has gear-like irregularities 52 on outer peripheral portion 51, for example, as shown in FIG. The unevenness 52 makes it easy for the rotating member 50 to bite into the glass ribbon G. Although the shape of the convex part 52a of the unevenness | corrugation 52 is not specifically limited, For example, as shown in FIG. 3, you may form in a taper shape (for example, square pyramid shape). As shown in FIG. 4, the gear-shaped irregularities 52 are formed in a row in the thickness direction (Y direction in FIG. 1) of the outer peripheral portion 51 of the rotating member 50, but may be formed in a plurality of rows.

Rotating member 50 does not have a refrigerant flow path inside. Since the rod portion 64 inserted into the through hole of the rotating member 50 is a member different from the rotating member 50, the refrigerant flow path formed in the rod portion 64 is a refrigerant flow formed outside the rotating member 50. Road.

The rotating member 50 is formed of ceramics. Ceramics has a high temperature strength higher than that of conventional metals such as steel and heat-resistant alloys, so that the conventionally required refrigerant flow path is not required. Therefore, since the refrigerant does not flow inside the rotating member 50, the glass ribbon G is not easily cooled in the vicinity of the rotating member 50. As a result, the temperature of the glass ribbon G, and hence the thickness of the glass ribbon G, is stabilized, so that the flatness of the glass plate as a product is improved. Further, since the glass ribbon G is not easily cooled and hardened in the vicinity of the rotating member 50, the rotating member 50 is easy to bite into the glass ribbon G, and the grip property of the rotating member 50 to the glass ribbon G is improved. In the first low temperature region B of the float bath 20 that has been difficult to grip in the past (the glass ribbon G has a viscosity range of 10 ^6.7 to 10 ^7.65 dPa · s), the rotating member 50 can Grip can be achieved, and the occurrence of wave-like deformation of the glass ribbon G can be reduced. Therefore, the flatness of the glass plate can be improved.

Here, the temperature of the glass ribbon G is represented by the temperature at the center in the width direction of the glass ribbon G. The temperature of the glass ribbon G is measured by, for example, a radiation thermometer. When the glass type is alkali-free glass, the temperature range corresponding to a viscosity range of 10 ^6.7 to ^10.7.65 dPa · s is 937 ° C. to 1000 ° C.

The glass ribbon G is supported in the second low temperature range B ′ (range of 937 ° C. or more and less than 946 ° C. in the case of non-alkali glass) having a viscosity range of more than 10 ^7.5 to 10 ^7.65 dPa · s. It is preferably supported by the roll 40.

The glass ribbon G in the present embodiment, in the region viscosity is less than 10 ^{6.7 dPa} · s of the glass ribbon G, but is supported by the supporting roll 40 may be supported by a conventional support roll. In a region where the viscosity of the glass ribbon G is less than 10 ^6.7 dPa · s, the glass ribbon G can be gripped by a conventional rotating member.

The ceramic rotary member 50 is not particularly limited, for example, silicon carbide (SiC) quality ceramics, silicon nitride _(Si 3 _{N 4)} such quality ceramics are used. Silicon carbide and silicon nitride have high resistance to the splash of molten tin S and the vapor of molten tin S, and are excellent in high temperature strength and creep characteristics.

The ceramic type of the rotating member 50 is selected according to the type of glass plate (ie, glass ribbon G) that is the product. For example, when the glass plate is alkali-free glass, silicon nitride ceramics excellent in thermal shock resistance are suitable. In the case of non-alkali glass, the temperature in the float bath 20 tends to be high, so that the higher the thermal shock resistance, the higher the degree of freedom of operation. Furthermore, the higher the temperature, the more likely the reactivity with the glass ribbon G and the molten tin S becomes a problem, but the silicon nitride ceramic tends to have a low reactivity. When the glass plate is soda lime glass, silicon carbide ceramics or alumina ceramics can be used in addition to silicon nitride ceramics.

The glass plate as a product is not particularly limited, but may be for a flat panel display (FPD) such as a liquid crystal display (LCD), a plasma display (PDP), or an organic EL display. In recent years, thinning of FPDs has progressed, and thinning of glass plates for FPDs has progressed. In particular, in the case of a glass plate for a display substrate, a glass plate of 0.7 mm or less, more preferably 0.3 mm or less, more preferably 0.2 mm or less, particularly preferably 0.1 mm or less is desired. Therefore, the thickness of the glass ribbon G is reduced, the shrinkage force in the width direction of the glass ribbon G is increased, and the molding temperature of the glass ribbon G is increased. As described above, the support roll 40 according to the present embodiment is suitable for forming a glass plate for FPD because the glass ribbon G is not easily cooled.

The kind of glass plate which is a product is not particularly limited. The composition of the glass plate is, for example, expressed as mass% on the basis of oxide, SiO ₂ : 50 to 75%, Al ₂ O ₃ : 0.1 to 24%, B ₂ O ₃ : 0 to 12%, MgO: 0 ~ 10%, CaO: 0-14.5%, SrO: 0-24%, BaO: 0-13.5%, Na ₂ O: 0-20%, K ₂ O: 0-20%, ZrO ₂ : 0 to 5%, MgO + CaO + SrO + BaO: 5 to 29.5%, Na ₂ O + K ₂ O: 0 to 20%.

The composition of the glass plate may be formed of non-alkali glass, for example. The alkali-free glass is a glass that does not substantially contain an alkali metal oxide (Na ₂ O, K ₂ O, Li ₂ O). The total content (Na ₂ O + K ₂ O + Li ₂ O) of the alkali metal oxide content in the alkali-free glass may be, for example, 0.1% or less.

The alkali-free glass is, for example, expressed in terms of mass percentage based on oxide, SiO ₂ : 50 to 70%, preferably 50 to 66%, Al ₂ O ₃ : 10.5 to 24%, B ₂ O ₃ : 0 to 12%, MgO: 0 to 10%, preferably 0 to 8%, CaO: 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, ZrO ₂ : 0 to 5% MgO + CaO + SrO + BaO: 8 to 29.5%, preferably 9 to 29.5%.

The alkali-free glass has a high strain point, and when considering the solubility, it is preferably expressed in terms of mass percentage based on oxide, SiO ₂ : 58 to 66%, Al ₂ O ₃ : 15 to 22%, B ₂ O ₃ : 5 to 12%, MgO: 0 to 8%, CaO: 0 to 9%, SrO: 3 to 12.5%, BaO: 0 to 2%, MgO + CaO + SrO + BaO: 9 to 18% is there.

When considering the high strain point, the alkali-free glass is preferably expressed in terms of mass percentage based on oxide, SiO ₂ : 54 to 73%, Al ₂ O ₃ : 10.5 to 22.5%, B ₂ O ₃ : 0 to 5.5%, MgO: 0 to 10%, CaO: 0 to 9%, SrO: 0 to 16%, BaO: 0 to 2.5%, MgO + CaO + SrO + BaO: 8 to 26% is there.

When the type of the glass plate is non-alkali glass, at least a portion of the rotating member 50 that contacts the glass ribbon G may be silicon nitride ceramics, and the entire rotating member 50 is not silicon nitride ceramics. Also good. For example, a silicon nitride ceramic layer may be formed on a base material made of metal, carbon or other ceramics by film formation, bonding or fitting. Thus, different types of ceramics may be used for each part of the rotating member 50. In the present embodiment, the entire rotating member 50 is formed of silicon nitride ceramics.

The silicon nitride ceramics may be a sintered body obtained by sintering a molded body made of a mixed powder containing silicon nitride powder and sintering aid powder. As the sintering method, there are an atmospheric pressure sintering method, a pressure sintering method (including hot press sintering, gas pressure sintering) and the like. As the sintering aid, for example, at least one selected from alumina (Al ₂ O ₃ ), magnesia (MgO), titania (TiO ₂ ), zirconia (ZrO ₂ ), and yttria (Y ₂ O ₃ ) is used. It is done.

The silicon nitride ceramic has an aluminum (Al) content of 0.1% by mass or less, preferably less than 1% by mass, and a magnesium (Mg) content of 0.7% by mass or less, preferably 0.7% by mass. The titanium (Ti) content is 0.9 mass% or less, preferably less than 0.9 mass%. When the Al content, the Mg content, and the Ti content are in the above ranges, it is difficult to react with the glass ribbon G, and the glass ribbon G is difficult to adhere, so that good durability is obtained. In addition, 0 mass% may be sufficient as Al content, Mg content, and Ti content, respectively.

The silicon nitride ceramic has a zirconium (Zr) content of 3.5% by mass or less, preferably less than 3.5% by mass, and a yttrium (Y) content of 0.5% by mass or more, preferably 0.5%. It is preferable to be more than 10% by mass, more preferably less than 10% by mass. Zr and Y are components that are less likely to interdiffuse with the glass ribbon G as compared with Al, Mg, and Ti, and thus may be contained in the above range. By containing in the above range, sintering of the silicon nitride powder can be promoted. Zr is an optional component, and the Zr content may be 0% by mass.

The silicon nitride ceramic of the present embodiment is a sintered body obtained by a normal pressure sintering method or a pressure sintering method, but may be a sintered body obtained by a reactive sintering method. . The reaction sintering method is a method in which a molded body formed of metal silicon (Si) powder is heated in a nitrogen atmosphere. Since the reaction sintering method does not use a sintering aid, a high-purity sintered body can be obtained, and the durability of the sintered body with respect to the glass ribbon G can be improved.

A circular hole is formed through the center of the rotating member 50. The rod portion 64 is inserted through the circular hole. The inner diameter of the circular hole is larger than the outer diameter of the rod portion 64.

The insertion hole is formed through the rotating member 50. The

shaft portions

67 and 68 are inserted through the insertion holes. The inner diameter of each insertion hole is larger than the outer diameter of the

corresponding shaft portions

67 and 68.

FIG. 5 is a front view showing a modified example (1) of the rotating member. FIG. 6 is an example of a cross-sectional view taken along the line VI-VI in FIG. FIG. 7 is a first diagram showing dimensions of the convex shape of the rotating member of FIG. 6. FIG. 8 is a second diagram illustrating the dimensions of the convex shape of the rotating member in FIG. 6.

5A or the like is used in place of the rotating member 50 shown in FIG. For example, as shown in FIG. 6, the outer peripheral surface 56 </ b> A of the rotating member 50 </ b> A of the modification (1) has a curved shape with a cross-sectional shape that protrudes radially outward over the entire circumference. In the outer peripheral surface 56A of the rotating member 50A, the central portion in the axial direction protrudes radially outward from both end portions in the axial direction. The outer peripheral surface 56A of the rotating member 50A has the same cross-sectional shape over the entire circumference. The rotating member 50A does not have gear-like irregularities on the outer peripheral surface 56A. The rotating member 50A can bite into the glass ribbon G even if there are no gear-like irregularities. This is because the refrigerant does not flow inside the rotating member 50A, so that the glass ribbon G is not cooled strongly in the vicinity of the rotating member 50A and is not easily hardened.

For example, as shown in FIG. 7, the convex curved radius of curvature Ra is preferably R1 to R100 mm, more preferably R3 to R50 mm, and even more preferably R5 to R30 mm in consideration of gripping force with the glass ribbon G. R10 to R20 mm are particularly preferable. In the convex curved shape, for example, as shown in FIG. 8, a curvature radius Rb at the central portion in the axial direction and a curvature radius Rc at both end portions in the axial direction may be a composite R. At this time, the radii of curvature Rb and Rc are preferably R1 to R100 mm, more preferably R3 to R50 mm, still more preferably R5 to R30 mm, and particularly preferably R10 to R20 mm. The convex curve may have a flat portion in part, but it is preferable not to have a flat portion because the grip force with the glass ribbon G is stable.

In consideration of the grip force with the glass ribbon G, the radial width d of the rotating member 50A in the convex curved shape shown in FIG. 7 is preferably 0.5 mm or more, more preferably 1 mm or more, and further preferably 2 mm or more. . Similarly, the radial width d of the rotating member 50A in the convex curved shape is preferably 5 mm or less, and more preferably 4 mm or less.

The radius r of the rotating member 50A shown in FIG. 7 is preferably 100 mm or more, more preferably 150 mm or more, and still more preferably 180 mm or more in consideration of prevention of contact between the mounting member 60 and the glass ribbon G and the horizontality of the shaft member 70. Considering the positional adjustment between the rotating member 50A and the glass ribbon G and the fine adjustment of the rotational speed of the rotating member 50A, 350 mm or less is preferable, 300 mm or less is more preferable, and 270 mm or less is more preferable.

The thickness w of the rotating member 50A is preferably 5 mm or more, more preferably 10 mm or more, further preferably 15 mm or more, particularly preferably 30 mm or more, and the flatness of the glass ribbon G is improved in consideration of the grip force with the glass ribbon G. In view of preventing unnecessary increase in grip width, it is preferably 120 mm or less, more preferably 100 mm or less, further preferably 80 mm or less, still more preferably 60 mm or less, and particularly preferably 40 mm or less.

Thus, as shown in FIGS. 6 to 8, the outer peripheral surface 56A of the rotating member 50A is a curved shape whose cross-sectional shape is radially outward and has no gear-like unevenness, as shown in FIGS. It is hard to break and the molding and processing costs are reduced. 6 to 8 is preferable because the glass ribbon G can be stably formed into a sheet glass.

The cross-sectional shape of the outer peripheral surface 56A of the rotating member 50A of the modified example (1) is a curved shape convex outward in the radial direction, but may be flat. In this case, the rotating member is between the outer peripheral surface and the side surface. The cross-sectional shape may have a rounded boundary. In these modifications, a plurality of protrusions having a height of 0.1 to 10 mm may be provided on the outer peripheral surface of the rotating member, or a plurality of grooves having a depth of 0.1 to 10 mm may be provided on the outer peripheral surface of the rotating member. . Moreover, you may provide both a processus | protrusion and a groove | channel on the outer peripheral surface of a rotation member. The height of the protrusion and the depth of the groove are measured using the outer peripheral surface of the rotating member as a reference surface. The height of the protrusion and the depth of the groove are smaller than the radius r shown in FIG. 7, the curvature radius Ra shown in FIG. 7, and the curvature radii Rb and Rc shown in FIG.

9 to 12 are front views showing modified examples (2) to (5) of the rotating member. In the modified examples (2) to (5), the rotating members 50B to 50E are provided with notches 57B or through

holes

58C, 58D, and 59E in order to relieve stress caused by a temperature gradient in the rotating members 50B to 50E. Is formed. A conventional metal rotating member has a cooling flow path therein, and thus it is difficult to provide the notch and the through hole. The rotating member of this modification does not require cooling, and there is no need to provide a cooling channel. Furthermore, the notch and the through hole can be easily and arbitrarily provided. When the notch or the through hole is provided in the rotating member, the stress of the rotating member can be relieved, and further, residual stress at the time of manufacturing the rotating member is also relieved, and distortion and breakage of the rotating member can be prevented. .

The rotating member 50B shown in FIG. 9 is used in place of the rotating member 50 shown in FIG. The rotating member 50B of the modified example (2) includes a circular hole 53B through which the rod portion 64 (see FIG. 4) is inserted, and

insertion holes

54B and 55B through which the shaft portions 67 and 68 (see FIG. 4) are inserted. In addition, a plurality of arc-shaped cutouts 57B are formed at intervals along the inner periphery of the circular hole 53B.

A rotating member 50C shown in FIG. 10 is used in place of the rotating member 50 shown in FIG. The rotating member 50C of the modified example (3) includes a circular hole 53C through which the rod portion 64 (see FIG. 4) is inserted, and

insertion holes

54C and 55C through which the shaft portions 67 and 68 (see FIG. 4) are inserted. In addition, a plurality of radial through holes 58C are radially formed.

A rotating member 50D shown in FIG. 11 is used in place of the rotating member 50 shown in FIG. The rotating member 50D of the modified example (4) has a circular hole 53D through which the rod portion 64 (see FIG. 4) is inserted and

insertion holes

54D and 55D through which the shaft portions 67 and 68 (see FIG. 4) are inserted. In addition, a plurality of arc-shaped through holes 58D that are long in the circumferential direction are formed.

The rotating member 50E shown in FIG. 12 is used in place of the rotating member 50 shown in FIG. The rotating member 50E of the modified example (5) includes a circular hole 53E through which the rod portion 64 (see FIG. 4) is inserted, and

insertion holes

54E and 55E through which the shaft portions 67 and 68 (see FIG. 4) are inserted. In addition, a plurality of circular through holes 59E are formed.

The dimensional shape and arrangement position of the notch 57B and the through

holes

58C, 58D, and 59E are obtained by, for example, stress analysis such as a finite element method.

In Examples 1 to 4, the relationship between the wettability of the sintered body with respect to the molten glass and the impurities contained in the sintered body was examined.

The test piece and the test plate for evaluation were produced by processing a sintered body of silicon nitride (Si ₃ N ₄ ) -based ceramics that differs for each example.

The content of impurities in the sintered body was measured by analyzing a test piece cut into a square shape from the sintered body by glow discharge mass spectrometry. Impurities to be measured are included as sintering aids, and are aluminum (Al), magnesium (Mg), titanium (Ti), zirconium (Zr), and yttrium (Y).

The wettability of the sintered body with respect to the molten glass was measured with a high temperature wettability tester (manufactured by ULVAC-RIKO, WET1200). Specifically, a square glass piece of alkali-free glass (manufactured by Asahi Glass Co., Ltd., AN100) was placed on a test plate processed to a thickness of 1 mm, heated in a nitrogen atmosphere to 1150 ° C. in 10 minutes, and 1150 ° C. Was maintained for 10 minutes to form a molten glass, and the temperature was lowered from 1150 ° C. to 1050 ° C. in 90 seconds and maintained at 1050 ° C., and the contact angle of the droplet was measured. The measurement was performed when the temperature dropped to 1050 ° C., and after 2 hours, 4 hours, 6 hours, and 8 hours from that point. A larger contact angle means that the molten glass is less likely to get wet with the sintered body, and therefore indicates that the reactivity between the molten glass and the sintered body is low. In addition, the smaller the change in the contact angle with time, the easier the wettability is sustained.

Evaluation results are shown in Table 1 and FIG. In FIG. 13, the vertical axis represents the contact angle (°), and the horizontal axis represents the elapsed time (h: hours). In addition, 10000 mass ppm is 1 mass%.

As apparent from Table 1 and FIG. 13, the Al content is 0.1% by mass or less, preferably less than 0.1% by mass, and the Mg content is 0.7% by mass or less, preferably less than 0.7% by mass. Ti content is 0.9 mass% or less, preferably less than 0.9 mass%, Zr content is 3.5 mass% or less, preferably less than 3.5 mass%, and Y content is 0.5 mass%. More than 10% by mass, preferably more than 0.5% by mass and less than 10% by mass, there is little change in the contact angle over time, and the contact angle after 8 hours is large, so that good durability can be obtained. I understand that.

As mentioned above, although embodiment of the manufacturing method of a glass plate and the manufacturing apparatus of a glass plate was demonstrated, this invention is not limited to the said embodiment. The present invention can be modified and improved within the scope of the gist of the claims.

For example, the support roll 40 of the above embodiment is used in the float method, but may be used in other forming methods, for example, the fusion method.

In the case of the fusion method, the support rolls are columnar or cylindrical, and are used in pairs so as to sandwich the glass ribbon from the front side and the back side, and the support roll group consisting of the two support rolls is a glass ribbon. Plural pairs are arranged on both sides in the width direction.

In the case of the fusion method, the glass plate forming apparatus has a bowl-shaped member to which molten glass is continuously supplied. The molten glass overflowing from the upper edges of the left and right sides of the bowl-shaped member flows down along the left and right sides of the bowl-shaped member, and merges at the lower edge where the left and right sides meet, and is integrated with the glass ribbon. Become. The glass ribbon is fed downward while being supported by a plurality of pairs of support rolls.

This application claims priority based on Japanese Patent Application No. 2013-104379 filed with the Japan Patent Office on May 16, 2013. The entire contents of Japanese Patent Application No. 2013-104379 are incorporated herein by reference. To do.

DESCRIPTION OF SYMBOLS 10 Glass plate forming apparatus 20 Float bath 40 Support roll 50 Rotating member 51 Outer peripheral part 52 Concavity and convexity 56A Outer peripheral surface G Glass ribbon

Claims

A method for forming a glass plate, comprising a step of suppressing the shrinkage in the width direction of a belt-like glass ribbon,
A support roll for supporting the glass ribbon in a viscosity range of 10 6.7 to 10 7.65 dPa · s is provided;
The support roll has a rotating member in contact with the glass ribbon at the tip,
A method for forming a glass plate, wherein the rotating member does not have a coolant channel inside and is formed of ceramics.
The method for forming a glass plate according to claim 1, wherein at least a portion of the rotating member that comes into contact with the glass ribbon is formed of silicon nitride ceramics.
The silicon nitride ceramic is a sintered body having an aluminum (Al) content of 0.1% by mass or less, a magnesium (Mg) content of 0.7% by mass or less, and a titanium (Ti) content. The method for forming a glass plate according to claim 2, wherein the amount is 0.9 mass% or less.
4. The silicon nitride ceramic according to claim 3, wherein the content of zirconium (Zr) is 3.5 mass% or less and the content of yttrium (Y) is 0.5 mass% or more and 10 mass% or less. Glass plate forming method.
The method for forming a glass plate according to any one of claims 1 to 4, wherein the outer peripheral surface of the rotating member is formed in a curved shape having a cross-sectional shape protruding radially outward over the entire periphery.
The method for forming a glass plate according to any one of claims 1 to 4, wherein the rotating member has gear-like irregularities on an outer periphery.
A belt-shaped glass ribbon comprising a support roll that supports the glass ribbon in a viscosity range of 10 6.7 to 10 7.65 dPa · s;
The support roll has a rotating member in contact with the glass ribbon at the tip,
An apparatus for forming a glass plate, wherein the rotating member does not have a coolant channel inside and is formed of ceramics.
The glass plate forming apparatus according to claim 7, wherein at least a portion of the rotating member that comes into contact with the glass ribbon is formed of silicon nitride ceramics.
The silicon nitride ceramic is a sintered body having an aluminum (Al) content of 0.1% by mass or less, a magnesium (Mg) content of 0.7% by mass or less, and a titanium (Ti) content. The apparatus for forming a glass sheet according to claim 8, wherein the amount is 0.9 mass% or less.
10. The silicon nitride ceramic according to claim 9, wherein the content of zirconium (Zr) is 3.5 mass% or less and the content of yttrium (Y) is 0.5 mass% or more and 10 mass% or less. Glass plate forming equipment.
The glass plate forming apparatus according to any one of claims 7 to 10, wherein an outer peripheral surface of the rotating member is formed in a curved shape having a cross-sectional shape projecting radially outward over the entire circumference.
The glass plate forming apparatus according to any one of claims 7 to 10, wherein the rotating member has gear-like irregularities on an outer periphery.
A method for producing a glass plate, comprising a step of gradually cooling and cutting a band-shaped glass ribbon obtained by the method for forming a glass plate according to any one of claims 1 to 6.