WO2008020509A1

WO2008020509A1 - Heat-resistant tempered glass and process for producing the same

Info

Publication number: WO2008020509A1
Application number: PCT/JP2007/063172
Authority: WO
Inventors: Masafumi Yamamoto
Original assignee: Asahi Glass Company, Limited
Priority date: 2006-08-14
Filing date: 2007-06-29
Publication date: 2008-02-21
Also published as: KR20150095942A; CN101500956A; JPWO2008020509A1; CN101500956B; JP5799482B2; JP2015187076A; KR20140135846A; KR20090041363A; JP5924439B2

Abstract

A heat-resistant tempered glass that is for windows and doors of building and housing unit, having a strength satisfying flame shielding performance, and that realizes high image quality. The tempered glass is one resulting from physical strengthening processing of a glass plate cut into given size, characterized in that there is provided an edge portion polished plane inclined against the surface of glass plate and an end face thereof, and that the edge portion polished plane has an angle of 135° to 170° against the glass plate surface, and that a break in a corner portion made by the edge portion polished plane and the glass plate surface has a length of 200 μm or less in the direction of edge line and has a maximum width of 100 μm or less in the direction perpendicular to the edge line.

Description

Specification

Heat-resistant tempered glass and method for producing heat-resistant tempered glass

Technical field

TECHNICAL FIELD [0001] The present invention relates to a heat-resistant tempered glass, and more particularly to a heat-resistant tempered glass used for building or residential fireproof windows and fireproof doors, and a method for producing the heat-resistant tempered glass.

Background art

In general soda lime glass, the tensile stress generated at the end of the fire door during a fire test or fire that is stipulated in the Building Standards Law causes damage. This tensile stress is caused by a temperature difference between the end fitted in the sash frame and the surface exposed to the flame. Conventionally, as a fireproof glass used for the purpose of preventing the spread of fire, a glass with a metal net embedded so as not to cause an opening due to dropping even if the glass breaks in the event of a fire is generally used. In recent years, fire-resistant glass that exhibits fire-proof performance without breaking the glass in the event of a fire has been proposed because of its appearance and other advantages.

[0003] In order to ensure the strength of the edge of such a fireproof glass, after the glass plate is heated close to the soft saddle point, the glass plate is rapidly cooled by blowing compressed air or the like, heat treatment for physical strengthening, It is necessary to increase the surface compressive stress by so-called physical strengthening treatment. In this process, even if the glass plate is relatively soft, it is cooled rapidly by blowing compressed air or the like onto the glass surface, which may cause rapid cooling marks or warpage on the glass surface, resulting in poor flatness. A decline is inevitable.

[0004] In addition, when the glass cut end surface after cutting is not polished, the glass plate is at a corner portion at the boundary between the glass plate surface and the end surface when a tensile stress is applied to the end portion. In the case of a fine crack, especially when cutting, the stress is concentrated on the cracked portion of the wheel cutter and the diamond cutter, resulting in destruction. Therefore, in order to improve the strength of the end surface of the glass plate (hereinafter referred to as “edge strength”), how to chamfer is important. The edge strength refers to the tensile stress generated on the end surface when the end of the glass plate is broken.

[0005] In cited document 1, fire resistance is obtained by polishing the edge of glass into a curved shape, then polishing the boundary between the curved edge and the flat surface (plate surface), and further improving the edge strength by physical strengthening treatment. Glass has been proposed. However, in the method for polishing the edge of the glass plate described in the cited reference 1, it is necessary to use a grinding wheel with a special curved surface, and it is necessary to manufacture a new polishing wheel. Processing costs and quality control costs also increase.

[0006] Cited Document 2 proposes a fireproof glass in which only the yarn surfaces at both ends of the end surface of the glass are chamfered and the edge strength is improved by physical strengthening treatment.

[0007] As described above, among the fire-resistant glasses, the glass that has been subjected to the physical strengthening treatment after cutting the glass plate and polishing the end portion thereof by a method different from a normal one to increase the heat-resistant strength is called a heat-resistant toughened glass. The performance required for heat-resistant tempered glass is, for example, that it satisfies the flame shielding performance stipulated in Article 2, Item 9-2 of the Building Standards Act and Article 64 of the Building Standards Act. As a test for evaluating this, for example, there is a fire prevention test based on the heating temperature curve of IS0834-1: 1999. In order to pass this, it is required that there is no damage such as cracks through which the flame passes during the fire prevention test, and there are no gaps. Except for this, it is necessary that the glass does not break. For this purpose, the value obtained by adding the edge strength before physical strengthening after edge processing and the surface compressive stress near the edge by physical strengthening, that is, the edge strength possessed by the glass plate after physical strengthening is obtained. It is necessary to exceed at least the edge tensile stress generated during the above test. The edge strength after the physical strengthening treatment increases as the surface compressive stress of the edge increases, and the reliability against the tensile stress generated during the test increases. However, if the glass temperature at the start of quenching is too high in the physical strengthening process to increase the surface compressive stress of the edge, as described above, heat treatment marks and warpage appear on the glass plate, resulting in poor flatness. The image quality as a board cannot be satisfied.

In addition, heat-resistant tempered glass has been used in buildings such as condominiums and offices. Recently, demand for residential use has been increasing. However, when glass is used for residential windows and doors, the end face is processed using either of the methods of cited references 1 and 2, and physical strengthening treatment is performed under the same conditions as before, building Because it is thinner than the glass used in the film, heat treatment traces and warpage are likely to occur, and video quality is likely to be a problem immediately.

Patent Document 1: Japanese Patent Laid-Open No. 9 71429

Patent Document 2: Japanese Patent Laid-Open No. 11-79769 Disclosure of the invention

Problems to be solved by the invention

[0009] The present invention has been made in view of the above circumstances, and is a glass for windows and doors for buildings or houses, and is a heat-resistant tempered glass that satisfies the flame-shielding performance even if the surface compressive stress is small, and It aims at providing the manufacturing method of heat-resistant tempered glass. Another object of the present invention is to provide a heat-resistant tempered glass and a method for producing the heat-resistant tempered glass that satisfy the flame shielding performance even when the surface compressive stress is small and have high image quality.

Means for solving the problem

[0010] According to the above object, the present invention has been carried out by finding a method for processing an end portion that can ensure the strength as a heat-resistant tempered glass even if the surface compressive stress is reduced. In addition to this edge processing method, the present invention finds and implements a physical enhancement processing method that satisfies high image quality.

That is, in order to achieve the above object, in the tempered glass of the present invention, a glass plate cut into a predetermined size is a tempered glass subjected to a physical strengthening treatment, and is a ridge portion inclined with respect to the glass plate surface and the end surface. An angle formed with the glass plate surface.

135 degrees or more and 170 degrees or less, and the corner portion formed by the ridge-polished surface and the glass plate surface (also referred to as “chip”) has a ridge line length of 200 μm or less, The maximum width in the direction perpendicular to the ridgeline is 100 μm or less.

In the tempered glass of the present invention, the compressive stress on the surface of the glass plate is such that the plate thickness is 2.5 mm or more and less than 3.5 mm, 70 MPa or more and 155 MPa or less, 3.5 mm or more and less than 4.5 mm, 75 MPa or more and 160 MPa. Less than 4.5mm, less than 5mm, less than 85MPa, less than 170MPa, less than 5.5mm, less than 3mm, more than 95MPa, less than 180MPa, less than 6.3mm, less than Om 105, less than 105MPa, less than 190MPa, more than 7.Omm 9. Less than Omm, 120 MPa or more and 205 MPa or less, 9. Omm or more, 11. Less than Omm, 135 MPa or more and 220 MPa or less, 11.0 mm or more, 20. Omm or less, 150 MPa or more and 240 MPa or less.

[0011] Further, in the tempered glass of the present invention, it is preferable that the end face of the glass plate is polished.

[0012] Furthermore, the tempered glass of the present invention is characterized in that the ridge polished surface is thrown onto the glass end surface. The shadow width is preferably 0.3 mm or more and 1.3 mm or less, and the projection width on the glass plate surface side is preferably 0.3 mm or more and 3 mm or less.

[0013] In the method for producing tempered glass of the present invention, a tempered glass including a step of adding an end portion of a glass plate cut to a predetermined size and a step of physically strengthening the glass plate after the end portion processing. In the manufacturing method of the lath, the step of processing the end portion is performed by polishing an angle formed by a surface of the ridge portion and the glass plate surface with respect to the glass plate surface and the end surface to 135 degrees or more and 170 degrees or less. Form a ridge-polished surface, and the length of the chip in the corner between the ridge-polished surface and the glass plate surface is 200 μm or less, and the maximum width perpendicular to the ridgeline is 100 μm or less. It is characterized by that.

Further, in the method for producing tempered glass of the present invention, the physical strengthening step includes the steps of heating the polished glass plate to 620 ° C. or higher and 660 ° C. or lower; A process of rapidly cooling the glass plate with compressed air at a temperature of not less than 80 ° C and not more than 80 ° C. The pressure of the compressed air is not less than 2.5mm and less than 5mm, and lOkPa or more and 25kPa or less, 3. 5 mm or more, less than 5 mm, 7 kPa or more, 20 kPa or less, 4.5 mm or more 7. less than Omm, 6 kPa or more, 15 kPa or less, 7.0 mm or more, less than 9.0 mm, 5 kPa or more, 1 3 kPa or less, 9.0 mm or more, less than Omm 4kPa or more and 12kPa or less, 11. Omm or more 2 0. Omm or less, 2kPa or more lOkPa or less is preferable!

Furthermore, in the manufacturing method of the said tempered glass of this invention, it is preferable that the process of processing the said edge part adds grinding | polishing of the end surface of the said glass plate.

Furthermore, in the method for producing tempered glass according to the present invention, in the step of processing the end portion, the projected width of the ridge portion polished surface on the glass end surface side is 0.3 mm or more and 1.3 mm or less, and the glass plate surface side is processed. It is preferable to polish the projection width of 0.3mm to 3mm! /.

The invention's effect

[0014] According to the present invention, since the edge strength before the heat treatment by the physical strengthening treatment can be improved, a heat-resistant tempered glass and a method for producing the heat-resistant tempered glass satisfying the flame shielding performance even when the surface compressive stress by the heat treatment is low are obtained. Can do. Furthermore, since the necessary surface compressive stress can be reduced, the glass temperature of the heat treatment can be lowered, and a heat-resistant tempered glass having high image quality and a method for producing the heat-resistant tempered glass can be obtained. Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view of a tempered glass sheet according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram of a method for polishing a glass plate end according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a polished state of a tempered glass sheet according to an embodiment of the present invention using a cylindrical grindstone.

FIG. 4 is a schematic cross-sectional view of a polished state of a tempered glass sheet according to another embodiment of the present invention.

FIG. 5 is a cross-sectional dimension and part explanatory diagram of an end portion of a glass plate according to this example.

[Fig. 6] A plot (Weibull plot) on the Weibull probability axis based on the test results in Table 1.

Explanation of symbols

[0016] 1: glass plate, la: glass plate surface, lb: end surface, lc: ridge polished surface, Id: corner portion,

2 (2a, 2b, 2c): Grinding wheel, 3: Abrasive layer, 4: Rotating shaft, 5: Disk,

6: Polishing belt, 7: Cylinder.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the tempered glass according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a tempered glass according to an embodiment of the present invention. As shown in FIG. 1, the glass plate 1 is cut to a predetermined size, and only the ridges on both ends of the end surface lb are polished, so that the glass plate surface la and the ridge polishing surface lc inclined with respect to the end surface lb are formed. It is formed. The end face lb of the glass plate 1 may be left in the state of being cut, but in order to stabilize the variation in the edge strength due to the cutting quality, it is better to polish it, especially parallel polishing (glass A polishing method using a feeding (conveying) direction for polishing and a rotating method of the turret where the glass and the mortar's polishing surface hit each other is preferable.

[0018] The angle A formed by the glass plate surface la and the edge-polished surface lc is not less than 135 degrees and not more than 170 degrees.

When the angle A is smaller than 135 degrees, the edge formed by the ridge polished surface lc and the glass plate surface la is chipped, and the edge strength before the physical strengthening process is insufficient. High cooling processing is required, causing distortion and deformation in the glass, resulting in poor image quality. Also, if the angle A is greater than 170 degrees, high-accuracy ridge polishing is required, which increases the equipment cost. Preferred is 151 ° or more and 170 ° or less, which is less likely to cause chipping. More preferable It is 154 degrees or more and 170 degrees or less. Note that the angle A in FIG. 1 does not have to be the same for the upper and lower glass surfaces as long as they are within these ranges.

In normal ridge polishing, the angle A is set to a range that adds a manufacturing error to 135 degrees. If the corner is left without polishing the ridge, the corner will not be removed during post-processing or transportation. This is because it is easy to break, and it is not intended to positively improve the edge strength. In polishing the ridge according to the present invention, the angle A is set larger than usual in order to positively improve the edge strength. The reason why the edge strength is improved by increasing the angle A and the edge strength is improved by reducing the fracture starting from the corner Id after edge polishing, as will be described later, is expected. In the end machining, the direction of the reaction vector by pressing the mortar at the corner Id is almost perpendicular to the ridge polished surface lc. When the angle A is large, the reaction force vector is about half of the angle A, so that the force from the glass plate surface la and the edge polishing surface lc hardly occurs. On the other hand, when the angle A is small, the reaction force vector is close to the glass plate surface la, so that the chipping from the glass plate surface la is likely to occur.

For the above reasons, it is considered that as the angle A is larger, the edge strength after polishing the end portion where the cracks from the corner portion Id are difficult to occur is remarkably improved.

In general soda lime glass, in the event of a fire, the occurrence of a tensile stress that maximizes the end due to the temperature difference between the end fitted in the sash frame and the surface exposed to the flame is the cause of damage. It becomes. Most of the damages start from the burrs on the edges. Therefore, if there is a chip on the ridge line of the corner Id (the ridge line extending in the direction perpendicular to the paper surface in FIG. 1) formed by the ridge polished surface lc and the glass plate surface la, the size of the chip is one. Must be below a certain limit. The length of this ridge in the ridgeline direction must be 200 m or less. The length in the ridge line direction of the chip means the length of a ridge line (virtual ridge line) lost due to a chip generated on the ridge line of the corner Id. The maximum width in the direction perpendicular to the edge of the chip needs to be 100 m or less. The maximum width in the vertical direction to the edge of the chip means the maximum in the vertical direction with respect to the edge (virtual edge) lost due to the chip generated on the edge of the corner Id. The size of the chip should be measured using a digital microscope (for example, Keyence Co., Ltd., product name Digital Microscope Model No. VH-6200) by observing the corner 1d of the polished glass and measuring each distance. Obtained by. [0020] As described above, the angle A is set to 135 degrees or more and 170 degrees or less, the length of the force existing in the corner Id is 200 μm or less in the ridgeline direction, and the maximum width in the direction perpendicular to the ridgeline is 100 μm. If the following, the 3 σ lower limit value of the edge strength of the glass plate 1 exceeds 70 MPa. In order to ensure the edge strength, it is important to manage the surface roughness after grinding of the ridges based on the presence and size of the chip rather than the force that is an influence factor of the edge strength.

[0021] As described above, the edge strength can be remarkably improved by the edge processing method according to the present invention, so that the flameproof performance can be improved as a heat-resistant tempered glass. In addition, the edge compressive stress can be reduced by the improvement in edge strength, and even if the glass temperature at the start of cooling is lowered in the physical strengthening process, the image quality is maintained while maintaining the flameproof performance required for heat-resistant tempered glass. It can be improved.

As a method of evaluating the flame insulation performance, for example, in the fire prevention test based on the above-mentioned IS0834-1: 1999 heating curve, after inserting the tempered glass into the sash, the flame by the burner and the radiant heat in the furnace are applied from one side of the glass plate. To heat the glass. In this case, the tensile stress generated at the edge of the glass plate is added to the stress generated by the temperature difference between the center and the edge of the glass plate, and the bending stress generated by the deformation of the edge due to the deformation of the sash. The edge strength after physical strengthening treatment must exceed this tensile stress.

The tensile stress generated at the edge during this fireproof test was relatively high at least at the center of the glass plate, and it occurred at the time of temperature, and the rigidity of the glass plate changed due to warping, so it was not always obvious. For this reason, the edge strength after the physical strengthening treatment is on the safe side in the past, so it is relatively thick! Based on the results of the fire prevention test on the glass plate for buildings! Regardless, the required surface compressive stress was determined by assuming a constant tensile stress.

On the other hand, in the present invention, in order to achieve both of ensuring the flameproof performance and further ensuring the flameproof performance and further improving the image quality, the relationship between the thickness of the glass plate and the tensile stress is tested for fire prevention. It was determined by experiment. As a result, the thinner the plate thickness is, the shorter the time required to start the heating at which the maximum value is generated, the lower the glass temperature, and the smaller the deformation of the edge, so the temperature difference between the center and the edge of the glass plate It has been found that the maximum value of the generated stress is reduced. As a result, the plate thickness is about 2.5 to 9. The surface compressive stress is almost the same as that of), but it has a flame shielding performance even at a relatively low surface compressive stress in a thin plate, and high image quality can be obtained. Actually, the tensile stress generated at the edge during the fire prevention test is about 60 MPa less than 2.5 mm and less than 3.5 mm, and about 55 MPa less than 3.5 mm and less than 4.5 mm, compared to the case where the plate thickness is 10 mm. 4.5mm or more 5.5 less than 5mm, approx. 45MPa decrease, 5.5mm or more 6. Less than 3mm, approx. 35MPa decrease, 6.3mm or more 7. Less than Omm approx. 25MPa decrease, 7. Omm or more 9 Reduced by about 15 MPa below 0 mm. In addition, it increases about 15MPa at 11.Omm or more and 20.Omm or less.

Based on the above, a combination of reducing the surface compressive stress required as the plate thickness is reduced and improving the edge strength by the edge processing method according to the present invention described above, enhances heat resistance. The image quality can be further improved while maintaining the flameproof performance required for glass.

That is, in the tempered glass according to the present invention, each surface compressive stress with respect to the thickness of the glass plate is 2.5 mm or more and less than 3.5 mm, 70 MPa or more and 155 MPa or less, 3.5 mm or more and less than 4.5 mm, and 75 MPa or more. 160 MPa or less, 4.5 mm or more 5. Less than 5 mm 85 MPa or more 170 MPa or less, 5.5 mm or more 6. Less than 3 mm 95 MPa or more 180 MPa or less, 6.3 mm or more 7. Less than Omm 105 MPa or more 190 MPa or less, 7. Omm or more 9. Less than Omm 120MPa or more and 205MPa or less 9. Omm or more 11. Less than Omm 135MPa or more 22OMPa or less 11. Omm or more 20. Omm or less 150MPa or more and 240MPa or less is preferable.

More preferable range of surface compressive stress is that the thickness of the glass plate is 2.5 mm or more and less than 3.5 mm, 70 MPa or more and 130 MPa or less, 3.5 mm or more and less than 5 mm, 75 MPa or more and 135 MPa or less, 4.5 mm or more 5 Less than 5mm 85MPa or more 140MPa or less, 5.5mm or more 6. Less than 3mm 95MPa or more 150MPa or less, 6. 3mm or more 7. Less than Omm 105MPa or more 160MPa or less 7. Omm or more 9. Less than Omm 120MPa or more 175 MPa or less, 9. Omm or more 11. Less than Omm, 135 MPa or more and 190 MPa or less, 11. Omm or more, 20. Omm or less, 150 MPa or more and 210 MPa or less. By setting the surface compressive stress within these ranges, the margin for the tensile stress generated during the fire prevention test is relatively favorable. Although it is lower than the preferred range, it can maintain the necessary flameproof performance, and it is much closer to the image quality before physical strengthening processing, and can provide tempered glass.

The surface compressive stress can be measured with a differential refractometer described in JIS R3222 (2003 edition). The surface compressive stress is more likely not to be distributed in the plane of the glass plate because the glass plate is more likely to warp when the force on the image quality differs greatly between the edge and the center of the glass plate. It is preferable to satisfy the above range at least from the end face to 50mm.

[0022] The projection width B on the end surface lb side of the ridge polished surface lc and the projection width C of the ridge polished surface lc on the glass plate surface la side are appropriately determined according to the thickness of the glass plate. In order to minimize the stress concentration when tensile stress is generated at the edge of the glass due to cracks that occur during the cutting process when cutting the glass sheet, B is 0.3 mm or more and 1.3 mm or less, and C is 0.3 mm. In particular, C is preferably 3 mm or less, and C is preferably 0.5 mm or more and 1.3 mm or less.

FIG. 2 is a schematic explanatory view of a method for polishing a glass plate end portion according to an embodiment of the present invention, and FIG. 3 is a diagram of polishing with a reinforced glass cylindrical mortar according to an embodiment of the present invention. It is a schematic sectional view of a state. FIG. 4 is a schematic cross-sectional view of a polished state of tempered glass according to another embodiment of the present invention.

As shown in FIG. 2, a glass plate 1 to be polished is conveyed as shown by an arrow D, and a plurality of (three in the illustrated example) cylindrical bullion stones 2a for ridge polishing along the conveyance path, 2b and 2c are continuously arranged on a straight line. The grinding wheels 2a, 2b, 2c for polishing ridges arranged in a row are first equipped with a grinding wheel 2a with a large average abrasive grain size and high polishing efficiency. The final grindstone 2c is provided with a grindstone with a grain size corresponding to the required finished surface (rough finish, polished finish, polished finish, etc.). # 200 (average gun grain size 100 μm) for rough finish, # 500 (average grain size 45 μm) for polished finish, # 800 (average grain size 30 μm) for polished finish ) Is usually used.

[0024] As shown in Fig. 3 (a), a cylindrical mortar 2 having a substantially U-shaped barrel layer 3 formed on the circumference of a cylinder and provided with a rotation shaft 4 at the center of the cylinder, End face of glass plate 1 with respect to lb cross section If the glass plate 1 is cut with a cutting line (cutting groove) on the glass plate surface la with a wheel cutter, etc., the portion is weakest in strength and the portion (where cracks from the wheel cutter remain) ) Will be polished by each mortar 2.

[0025] The length of the force existing in the corner Id formed by the polishing surface lc and the glass plate surface la after this polishing step is 200 μm or less in the ridge line direction, and the maximum width in the direction perpendicular to the ridge line is 100 Since it is finished to μm or less, stress concentration at the chip when tensile stress is generated at the edge can be kept small.

[0026] The end surface lb has a cutting surface quality that can be either polished or not depending on the shape of the cylindrical grindstone 2 as shown in FIG. 3 (b). It has a stable and high edge strength. When polishing using such a mortar 2, the corner formed by the end surface 1 b of the glass plate 1 and the edge polishing surface lc is substantially chamfered, but this shape is not sufficient for edge strength. There is no effect. Further, when the end surface lb is subjected to parallel polishing before the ridge portion polishing of the present invention, higher edge strength can be obtained.

[0027] This polishing step is not limited to the above-described polishing method using the cylindrical grindstone 2. For example, as shown in FIG. 4 (a), the bullet layer 3 is mounted on the disk 5, Using a cup-shaped mortar 2 with a rotation axis 4 at its center, tilting the rotation axis 4 with respect to the end surface lb, and only the ridge lc (the corner of the boundary between the glass plate surface la and the end surface lb) As shown in FIG. 4 (b), the puff polishing method in which the outer peripheral surface of the polishing belt 6 is brought into contact with the ridge lc of the glass plate 1 as the workpiece, and polishing is performed, as shown in FIG. 4 (c). As shown in Fig. 2, a method is used in which a granule layer 3 is mounted on a cylinder 7 and a cylindrical mortar 2 having a rotation shaft 4 in its center is used and the rotation shaft 4 is inclined with respect to the end face lb. Or you may carry out by the grinding | polishing method which uses these together. In any case, the edge lc is polished according to the above-described embodiment of the present invention, and the length of the chip existing at the corner Id is 200 m or less in the ridge line direction and the maximum width in the direction perpendicular to the ridge line. Should be finished to less than 100 m.

Next, the physical reinforcement | strengthening process which concerns on embodiment of this invention is demonstrated. In the physical strengthening treatment according to the present invention, a glass plate that has been subjected to the above-described polishing process of the glass plate end is placed on a plurality of transfer rollers and heated while being moved horizontally, and then a rapid cooling is performed. Horizontal with a cooling area for blowing compressed air from above and below the glass plate Use a strengthening device.

Since the surface compressive stress is generated due to the temperature difference between the surface and the inside of the glass plate, the heat capacity differs when the glass plate thickness is different, and it is necessary to adjust the cooling rate according to the glass plate thickness. is there. The cooling rate varies depending on the glass plate temperature, compressed air temperature, and pressure before quenching. In addition, the cooling rate needs to be increased in order to increase the temperature difference in the thickness direction of the glass plate where the heat capacity decreases as the plate thickness decreases. For this reason, in order to ensure the surface compressive stress required when the plate thickness is small, the glass temperature before quenching can be increased, or the temperature of the compressed air can be decreased compared to when the plate thickness is large. It is necessary to increase the pressure of the pressure air.

In the physical strengthening treatment according to the present invention, the glass plate after the polishing step is heated to 620 ° C. or higher and 660 ° C. or lower to uniformly apply surface compressive stress to the glass surface. On the other hand, it is preferable to rapidly cool the compressed air at 5 ° C or more and 80 ° C or less by ejecting the nozzle force. By setting the temperature of the glass plate before quenching to 620 ° C or higher, cracks due to tensile stress temporarily generated during the cooling process can be prevented, and sufficient residual strain, that is, surface compressive stress, can be generated to improve flameproof performance. By ensuring that the temperature is 660 ° C. or less on the other side, traces and warpage of heat treatment are prevented, and good image quality is ensured. Since the air is compressed by the blower, the temperature of the compressed air becomes higher than the outside air temperature due to the rotational energy of the blower, and in some cases, it may rise to nearly 80 ° C. However, the cooling air can be lowered to nearly 5 ° C by cooling with a cooler.

Based on the relationship between the surface compressive stress and the cooling condition described above, the physical strengthening process according to the present invention sets the surface compressive stress required for a thin plate to be smaller, so the compressed air required for the expression of the surface compressive stress is used. The pressure of the plate is 2.5 mm or more and less than 3.5 mm, lOkPa or more and 25 kPa or less, 3.5 mm or more, less than 5 mm, 7 kPa or more and 20 kPa or less, 4.5 mm or more, 7 mm or less, 6 kPa or more and 15 kPa or less, 7 Omm or more 9. Less than Omm 5 kPa or more and 13 kPa or less, 9. Omm or more 11. Less than Omm 4 kPa or more and 12 kPa or less, 11. Omm or more 20 .Omm or less 2 kPa or more lOkPa or less. As a result, the pressure in the case of a thin plate may be smaller than the case where a conventional thick plate for a building is assumed. Example [0028] Specific examples of the present invention will be described below.

Float glass plate with nominal thickness of 3 mm and 4 mm 1 (length 10 cm x width 10

Ocm) was run at a feed rate of 4 mZmin, and the three grindstones were each rotated at a rotational speed of 3400 to 4000 rpm, and the samples were processed as follows.

[0029] [Example 1]: Float glass with a nominal thickness of 3 mm (average measured thickness 3.15 mm) 29 pieces are used in the order of cylindrical turret # 140, # 325, # 600 The ridges and end faces were polished.

[0030] [Example 2]: Float glass with a nominal thickness of 3 mm (average thickness measured 3.17 mm) 29 pieces were used in the order of cylindrical mortar # 120, # 270, # 500 The ridges and end faces were polished.

[0031] [Example 3]: 26 glass floats with a nominal thickness of 4 mm (average measured thickness of 3.75 mm) were used in the order of cylindrical mortar # 120, # 270, # 500 The ridges and end faces were polished.

[Comparative Example 1]: Float glass with a nominal thickness of 4 mm (average thickness measured 4.26 mm) was thread chamfered at both ends of the end surface as in the known technique of Reference 2 (FIG. 4). Use the # 500 grindstone with method (a)).

FIG. 5A is a cross-sectional dimension and part explanatory diagram of the glass plate end part according to the present example, and FIG. 5B is a cross-sectional dimension and part explanatory diagram of the glass end part according to the comparative example. In this example, the fracture starting point is the glass plate surface e, m, the angle f, 1, the ridge polishing surface g, k, the ridge polishing surface, and the end surface. Classified into h, j and end surface i. Since the ridges and end faces of the samples of Examples 1 to 3 were polished and finished with a circular mortar, the angles h and j formed by the ridge part polished surface and the end face have an R chamfered shape. The strength test was performed at a room temperature of 16-21 ° C and a relative humidity of 45-55%. 4-point bending with a load span of 30 cm and a support span of 90 cm capable of loading a uniform tensile stress on the center 30 cm of the processed side of the sample. Performed by test. Table 1 shows the results of the strength test (fracture stress, the position and number of fracture start points) and the cross-sectional dimensions of glass plate 1. The size of the chip is determined by observing the corner 1d of the polished glass using a digital microscope (manufactured by Keyence Corporation, product name Digital Microscope Model No. VH-6200) and measuring each distance. Obtained. The fracture stress in Table 1 is the end It is the value for the glass before physical strengthening after processing.

Figure 6 shows a plot on the Weibull probability axis (hereinafter referred to as the “Weibull plot”) based on the test results in Table 1. The Weibull plot is often used to evaluate the strength of materials with a large variation in fracture stress, such as glass, and plots the results of all fracture stresses except samples where the fracture origin is outside the load span. In this figure, the plot on the right indicates that the fracture stress is greater.

[0034] [Table 1]

[0035] As shown in Table 1, in Examples 1 to 3, the average fracture stress value increased by 30 MPa or more (about 1.5 times) compared to Comparative Example 1 in which both ends of the end face were chamfered. Even the lower limit of fracture stress 3σ increased by about 19MPa or more (about 1.4 times). The 3σ lower limit value means the failure probability of about 1Z1000, where σ is the standard deviation value and η is the number of samples. When the stress shown by the 3σ lower limit value occurs, about 1000 sheets This means that one of the glass plates will crack.

In addition, the fracture stress of Examples 1 to 3 from Fig. 6 is less than the fracture stress of Comparative Example 1, and the cumulative fracture probability that is important in the design of heat-resistant toughened glass is small. It is a big thing in the area. [0036] In the case of Examples 1 to 3, the location of the fracture starting point in this strength test is 5% or less at the corner Id (f, 1 in Fig. 5), which has been frequently generated in the past. Yes. In other words, glass breakage occurs when the angle A formed by the ridge polished surface lc and the glass plate surface la is not less than 135 degrees and not more than 170 degrees, and the corner Id formed by the ridge polished surface lc and the glass plate surface lb has a crack. It was confirmed that this can be suppressed by setting the length in the ridge line direction to 200 μm or less and the maximum width in the direction perpendicular to the ridge line to 100 μm or less.

[0037] The glass plate after the end processing is subjected to a physical strengthening treatment with a surface compressive stress of 150 MPa (for example, glass temperature before quenching 650 ° C, compressed air temperature 42 ° C, compressed air pressure 15.2 kPa). As a result, the edge strength necessary for flameproof performance can be obtained and high image quality can be obtained. In addition, the glass plate after the end processing described above is subjected to physical strengthening treatment with a surface compressive stress of 105 MPa (for example, glass temperature before quenching 635 ° C, compressed air temperature 41 ° C, compressed air pressure 8. OkPa). Edge strength necessary for flame performance is obtained and higher image quality is obtained.

[0038] As described above, when the end portion is processed under the conditions of the example, the 3σ lower limit value of the edge strength of the glass plate 1 exceeds 70 MPa. Therefore, in order to obtain the edge strength necessary for the flame barrier performance, the glass plate 1 can be improved in productivity if it is subjected to a physical strengthening treatment that imparts a lower surface compressive stress than in the past. Degradation of the image quality of the glass plate due to physical strengthening treatment of heat-resistant tempered glass plate with a thickness of 3 to 6 mm can be avoided.

Furthermore, in order to confirm that the tempered glass according to the present invention satisfies the flame-shielding performance as a heat-resistant tempered glass, using the tempered glass manufactured under the conditions shown in Table 2, IS083 4-1: 1999 A fire test was carried out based on the heating curve. The glass in the fire test was 1676mm in length and 1176mm in width, and 8mm edge was fitted in a steel sash. In addition, for the tempered glass with the conditions shown in Table 2, the striped pattern of the board (zebra boat) with a striped pattern before the fire test was projected on the surface of the tempered glass to evaluate the image quality. The results are also shown in Table 2. For the surface compressive stress, the product name FSM-30 (manufactured by Orihara Seisakusho Co., Ltd.) was used, and each point in the 50 mm area from the end face at the center of each of the four sides was measured and averaged. In the evaluation of the video quality in the table, when the glass quality is very good, the glass quality was evaluated as ◎, when it was good, 〇, and when it was not good, it was evaluated as △. Judgment criteria for flameproofing performance in the fire prevention test in the table is to the non-heating side There is no flame eruption that lasts for more than 10 seconds, there is no flame that continues for more than 10 seconds to the non-heated side, there is no damage such as cracks through which the flame passes, and there are no gaps. When all of these were satisfied, it was determined to be acceptable.

From the results shown in Table 2, the tempered glass according to the present invention satisfies the flame barrier performance, achieves both the flame barrier performance and the image quality by making the surface compressive stress within a preferable range, and further increases the surface compressive stress. It was found that by setting it within the preferred range, the flame shielding performance can be maintained and higher image quality can be satisfied.

In addition to Table 2, the fire prevention test was performed for the thickness of 7.7 mm under the processing conditions of Example 3 (surface compressive stress is 162 MPa) and the processing conditions of Comparative Example 1 (surface compressive stress is 198 MPa). In view of these data, the preferred surface compressive stress for other thicknesses is that the smaller the plate thickness found in connection with the present invention, the smaller the required surface compressive stress. It was determined based on the edge strength improvement obtained by polishing according to the present invention. Also, the pressure of compressed air required for each plate thickness was determined based on the required surface compressive stress.

[Table 2A]

[Table 2B] Manufacturing conditions and evaluation results Example 8 Example 9 Example 10 Example 11 1 Thickness (mm) 5.7 5.5.7 5.7 5.7 End processing method Example 3 Example 3 Example 3 Example 3 Surface compressive stress (MPa) 1 1 0 1 2 1 1 6 8 1 8 3 Glass temperature before quenching (in) 6 3 0 6 3 3 6 4 7 6 6 1 Compressed air temperature rc) 3 7 4 0 4 1 3 7 Compressed air pressure (kPa) 7 · 1 8. 0 1 3. 2 1 5.7 Fire test evaluation result Pass Pass Pass Pass

(Flame shielding performance)

Reflected image evaluation result ◎ ◎ 〇 Δ

[Table 2C]

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention can provide a heat-resistant tempered glass for homes having edge strength that satisfies flame barrier performance and high image quality. In addition, it is suitable for physical strengthening treatment of heat ray reflective glass or heat ray absorbing glass that usually requires heat resistance. It should be noted that the entire contents of the description, claims, drawings and abstract of Japanese Patent Application 2006-221114 filed on August 14, 2006 are cited here as disclosure of the specification of the present invention. Incorporated.

Claims

The scope of the claims

[1] A tempered glass in which a glass plate cut into a predetermined dimension is physically strengthened, and has a ridge-polished surface inclined with respect to the glass plate surface and the end surface, and the ridge-polished surface is the glass plate The angle formed by the surface is 135 ° or more and 170 ° or less, and the corner portion formed by the ridge polished surface and the glass plate surface has a ridge line length of 200 m or less and the maximum width perpendicular to the ridge line. Tempered glass characterized by having a thickness of 100 μm or less.

[2] The compressive stress on the surface of the tempered glass is

Thickness of 2.5 mm or more and less than 5 mm, 70 MPa or more and 155 MPa or less,

3. 5mm or more 4. Less than 5mm, 75MPa or more and 160MPa or less,

4. omm or more 5.5 and less than 5mm, 85MPa or more and 170MPa or less,

5. omm or more 6. less than 3mm, 95MPa or more, 180MPa or less,

6. 3mm or more 7. Less than Omm 105MPa or more and 190MPa or less,

7. Omm or more 9. Less than Omm 120MPa or more and 205MPa or less,

9. Omm or more 11. Less than Omm 135MPa or more and 220MPa or less,

11. Omm or more 20. Omm or less 150MPa or more and 240MPa or less

The tempered glass according to claim 1, wherein

[3] The tempered glass according to claim 1 or 2, wherein an end surface of the glass plate is polished.

[4] The projected width of the ridge-polished surface onto the end surface side of the glass plate is 0.3 mm to 1.3 mm, and the projected width onto the glass plate surface side is 0.3 mm to 3 mm. 4. The tempered glass according to any one of items 1 to 3.

[5] A method for producing tempered glass, comprising a step of processing an end portion of a glass plate cut into a predetermined dimension, and a step of physically strengthening the glass plate after the end portion processing, wherein the end portion And polishing the edge of the glass plate so that an angle between the glass plate surface and the glass plate surface is not less than 135 degrees and not more than 170 degrees to form an edge-polished surface. A method for producing tempered glass, characterized in that the length in the ridge line direction of a chip having a corner formed by a surface and the glass plate surface is 200 m or less and the maximum width in the direction perpendicular to the ridge line is 100 μm or less. .

[6] The physical strengthening process includes a step of heating the polished glass plate to 620 ° C. or more and 660 ° C. or less, and a compressed air of 5 ° C. or more and 80 ° C. or less to the heated glass plate. The glass The pressure of the compressed air is adjusted to a pressure of the plate thickness of 2.5 mm or more and less than 3.5 mm, lOkPa or more and 25 kPa or less,

3. 5mm or more 4. Less than 5mm, 7kPa or more and 20kPa or less,

4. 5 mm or more 7. Less than Omm 6 kPa or more and 15 kPa or less,

7. Omm or more 9. Less than Omm 5kPa or more and 13kPa or less,

9. Omm or more 11. Less than Omm 4kPa or more and 12kPa or less,

11. Omm or more 20. Omm or less 2kPa or more lOkPa or less

The method for producing tempered glass according to claim 5.

[7] The method for producing tempered glass according to [5] or [6], wherein the step of processing the end portion is performed by polishing the end face of the glass plate.

[8] In the step of processing the end portion, the projected width of the ridge portion polished surface onto the end surface side of the glass plate is set to 0.

The method for producing tempered glass according to any one of claims 5 to 7, wherein polishing is performed to 3 mm or more and 3 mm or less and a projection width on the glass plate surface side of 0.3 mm or more and 3 mm or less.