JP3308446B2 - Heat-strengthened glass sheet and method for finishing edge portion thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-strengthened glass sheet which is formed by, for example, a manufacturing method that does not use a hanging metal and can be used for a fire door or a fire window, and a method of finishing an edge portion thereof. More specifically, the present invention relates to a heat-strengthened plate gas that has been heat-strengthened over its entire surface and a method of finishing an edge portion thereof.

[0002]

2. Description of the Related Art When a glass sheet is used for a fire door or a fire window, a thermal cracking phenomenon of the glass sheet (a tensile stress is applied to an edge portion of the glass sheet supported by a window frame or the like due to thermal expansion generated in a central portion of the glass sheet due to heat. Acts, and its tensile stress becomes
It is necessary that the edge strength of the glass be high in order to prevent the occurrence of cracks by exceeding the edge strength provided in the sheet glass.

[0003] As a sheet glass for fire prevention, a glass with a net or a laminated glass with an intermediate layer made of hydrated alkali silicate is known, but in the former, there is a danger that an interpolated net blocks visibility and impairs transparency. In the latter case, there is a risk that the intermediate layer foams due to heat change and becomes opaque, thereby impairing the transparency. As a material which does not have these problems, a soda-lime glass which has been subjected to a heat strengthening treatment can be given.

[0004] The heat strengthening treatment is carried out at a softening point of the glass (720 to 720).
730.degree. C.), the sheet glass is heated in a temperature range (approximately 760.degree. C.) and a back pressure of 9 in a continuous air cooling section.
There is a method implemented by blowing cooling air at a very high pressure of 50 mmAq. However, with such a heat strengthening treatment of the sheet glass, although it is possible to impart a predetermined edge strength, in order to blow high pressure air to the sheet glass heated in a high temperature region exceeding the glass softening point as described above, There is a risk that the flatness of the glass surface may be lacking or warping may occur, causing a problem on the reflected image.

[0005] Conventionally, this type of heat-strengthened glass sheet includes:
The above-mentioned heat-strengthening process is performed, and the edge portion thereof is formed into a shape having a beveled corner as shown in FIG. 7, for example, a cup wheel (a grinding wheel or a grindstone is attached to the wheel side surface 20a. Some were polished by 20).

[0006]

According to the above-mentioned conventional heat-strengthened glazing, the above-mentioned heat-strengthening treatment (the softening point of the glass (720-730 ° C.) is required in order to be able to be used as a fire door or a fire window. ) (About 760)
C)), and in a continuous air-cooled portion, cooling air is blown at a very high pressure of 950 mmAq back pressure. There is a problem that a defect (a lack of flatness of the glass surface or a warp occurs, which causes an obstacle on a reflected image) occurs.

[0007] In order to solve this problem (surface unevenness / warpage), the heating temperature and the back pressure of the blowing air are set lower than those of the conventional heat strengthening treatment (hereinafter simply referred to as "heat strengthening embedding"). When low heat strengthening treatment is performed, sufficient edge strength cannot be secured, and heat distortion stress concentrates on the edge of the glass sheet, especially on the polished corners, due to the heat of a fire or fire prevention test. It is easy to destroy.
In particular, a sheet glass that has been heat-strengthened is subjected to tensile stress in the longitudinal direction at its end face, but when the end face is polished by a cup wheel, streaks (scratch) due to polishing are generated in the thickness direction of the sheet glass. Due to the formation, a new problem arises in that stress acting along the plate surface of the glass sheet is concentrated on streaks (scratches) and is easily broken.

Accordingly, an object of the present invention is to provide a heat-strengthened sheet glass capable of securing the edge strength of a predetermined sheet glass even if the degree of the heat-strengthening treatment is alleviated, and a method for finishing the edge portion thereof. Where you do it.

[0009]

[Means for Solving the Problems]

[Structure] The first aspect of the present invention is a polishing method in which an end surface of a thermally strengthened sheet glass that has been subjected to a thermal strengthening process is moved by moving a polishing portion to be contacted along a longitudinal direction of the end surface of the sheet glass. Finished with surface maximum unevenness of 0.05mm or less by processing
In addition , the boundary between the end face and the flat surface on the front and back of the glass sheet has a maximum surface roughness of 0.
Finished smoother than the end face at 007mm or less
Surface compressive stress by the heat strengthening treatment is 17
It is characterized configured to be a ~25kgf / mm ^2.

[0010]

[0011]

[0012] A second aspect of the present invention is to move a polished portion in contact with an end surface of a thermally strengthened sheet glass which has been subjected to a heat strengthening process along the longitudinal direction of the end surface of the sheet glass. Then, a polishing process is performed to make the surface maximum unevenness less than or equal to 0.05 mm. Then, the boundary between the end face and the flat surface of the glass sheet is reduced to a surface unevenness of 0. Carry out a finishing process so that it is smoother than the end face at 007 mm or less
And the surface compressive stress by the heat strengthening treatment is 17 to 25 k.
It is characterized configured to be a gf / mm ^2.

[0013]

[Operation] Generally, the internal stress generated in the sheet glass tends to concentrate on the ridge, and according to the first characteristic configuration of the present invention,
The end surface of the sheet glass that has been subjected to the heat strengthening process over the entire surface is moved to the abutment portion along the longitudinal direction of the end surface portion of the sheet glass to polish the surface.
With irregularities is finished to 0.05mm or less, the boundary portion between the end face portion and the plate glass front and back of the flat portion, said end surface maximum unevenness is less than or equal to 0.007mm by polishing treatment
Finished in a smoother state than the surface, and
Surface compressive stress due to processing in 17~25kgf / mm ²
Because of this , it is possible to obtain a thermally strengthened glass sheet in which stress is unlikely to concentrate on the edge portion.

According to a second feature of the present invention,
The end face of the heat-strengthened glass sheet that has been subjected to the heat-strengthening process over the entire surface is polished in the longitudinal direction thereof, and subjected to a polishing step of forming the surface maximum unevenness to be 0.05 mm or less. A processing and finishing step is performed so that the boundary between the flat surface of the glass plate and the flat surface is smoother than the end surface with the maximum surface unevenness of 0.007 mm or less.
And the surface compressive stress by the heat strengthening treatment is 17 to 25 k.
Since it is gf / mm ^2, it is possible to obtain a heat-strengthened glass sheet in which stress is unlikely to concentrate on the edge portion.

That is, since the end face of the sheet glass is polished along its longitudinal direction, a streak (scratch) due to polishing is similarly formed along the longitudinal direction of the end face of the sheet glass. Concentration of thermal destructive force or the like acting on the surface can be avoided. Furthermore, since the surface is finished in a smooth state with a maximum unevenness of 0.05 mm or less and a ridge is not formed on the end face, it is possible to avoid concentration of stress on the end face. The boundary between the end face and the flat part on the front and back of the sheet glass has a maximum surface roughness of 0.007 mm.
Since it is finished in a smoother state as follows, it is possible to eliminate the ridge portion where stress concentration is likely to occur even in the entire sheet glass, it is possible to avoid stress concentration on the edge portion of the sheet glass, and to achieve edge strength. Can be structurally improved. This increase in edge strength
It becomes about 4 kgf / mm ² .

Incidentally, even in the case of a flat shape in which stress concentration is unlikely to occur, the direction of the streaks (scratch) at the end face is formed in the thickness direction of the sheet glass, or the maximum surface unevenness exceeds 0.05 mm. In this case, stress tends to concentrate on the valleys and peaks of the irregularities. In addition, at the boundary between the end face and the flat surface of the front and back of the sheet glass, when the maximum surface unevenness is larger than 0.007 mm because the surface is a transition, the valley of the unevenness is obtained.・ Stress tends to concentrate on the peaks.

If the edge strength is increased as described above, the heat strengthening process is performed by performing heating in a lower temperature range or blowing air at a lower pressure than before. However, it becomes possible to secure the edge strength after the predetermined heat strengthening treatment, and it is possible to prevent the flatness of the glass surface or warp from occurring as in the related art, thereby causing a problem on the reflected image. Can be prevented.

By the way, in order to use ordinary heat-strengthened glass sheets as the first and second class fire doors in the fire test based on the Ministry of Construction Notification No. 1125, the edge strength of the glass sheet must be 21%.
kgf / mm ² (as the supporting state of the sheet glass, as shown in FIG. 2, a depth dimension (referred to as a allowance) (d) related to the sash at the periphery of the sheet glass is about 10 mm,
If the peripheral portion is not secured more than the holding hardware (9) having good thermal conductivity, there is a risk of causing the thermal cracking phenomenon. However, according to the present invention, the surface compressive stress due to the heat strengthening treatment is reduced. Since it is 17 to 25 kgf / mm ² , the edge strength is increased by 4 k by finishing the edge portion of the plate glass described above.
gf / mm ² and substantially 21 to 29 kgf /
The edge strength of ² mm ² can be ensured, and it can be used without problems as the above-mentioned class A and class B fire doors. The surface compressive stress due to the heat strengthening treatment is 25 k.
If it exceeds gf / mm ² , the surface compressive stress applied to the glass sheet tends to be non-uniform, which causes a problem.

When the sheet margin is set to about 15 mm and the sheet glass is supported, since the temperature difference between the peripheral part and the center part of the sheet glass becomes slightly large, the surface compressive stress is 18 kgf / mm ² or more is required. Further, in a supporting state (see FIG. 3) where the hanging margin (d) is about 15 mm and the holding hardware (9) is not used, a surface compressive stress of 22 kgf / mm ² or more is required. That is, in any of the above-mentioned supporting states, it becomes possible to use the above-mentioned class A and class B fire doors without any problem.

If the finishing step is carried out by buffing, the unevenness of the polished surface can be polished to the order of several μm, and a large polishing groove can be prevented from being formed at the boundary by polishing. The concentration of stress on the sheet glass in the groove can be suppressed, and the edge strength of the sheet glass can be further increased.

If the finishing step is carried out by heating and melting, the finished surface obtained by the finishing step can be finished in the same manner as the sheet glass surface, and the edge strength of the sheet glass can be further increased.

If the finishing step is performed by chemical dissolution, the finishing step itself can be performed by a simple operation procedure, and the efficiency of the finishing operation of the edge portion of the sheet glass can be improved. .

[Effects of the Invention] Therefore, according to the first heat-strengthened glass sheet of the present invention, the performance as fireproof glass can be maintained even if the sheet glass is heat-strengthened by a simpler method than before. As a result, it is possible to improve the quality of the sheet glass and reduce the operation cost of the heat strengthening treatment equipment.

Further, according to the second method of finishing the edge portion of the thermally strengthened sheet glass of the present invention, it is easy to prevent the internal stress from acting intensively on the edge portion of the sheet glass, and the edge strength of the sheet glass can be reduced. It is possible to increase than before,
Along with this, even if the sheet glass is thermally strengthened by a simpler method than before, the performance as fireproof glass can be maintained, improving the quality as a sheet glass and reducing the operating cost of the heat strengthening processing equipment. Can also be achieved.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 2 shows a sash (1) in which an edge portion (2) of a glass sheet (3), which is one embodiment of the thermally strengthened glass sheet of the present invention, is fitted. It shows the fire door (4) that is located.

The sash (1) is provided with an annular sash body (5) forming a door frame portion, and a holding portion (6) for holding the plate glass (3) on the sash body (5) is provided with the sash (1). The sash body (5) is detachably provided on the inner peripheral portion of the frame. The sash body (5),
The holding portion <6> is made of metal, and is formed in consideration of holding the glass sheet (3) even if a fire occurs. The holding portion (6) is composed of a pair of angle members, and the sash body () is formed in a state where a gap (7) capable of holding an edge portion (2) of the glass sheet (3) can be formed between each of the angle members. It is attached to 5).

In the gap (7), a setting block made of chloroprene rubber having a function of protecting the edge of the plate glass (3) (installed only in the gap (7) on the lower side of the sash (1)) (8) and a holding hardware (9) for holding the edge portion (2) of the plate glass (3) and fixing it to the holding portion (6).

The metal holding member (9) is formed of a thin metal plate, and the edge portion (2) is formed by positioning a sheet glass (3) in the gap (7).
Are formed so as to be elastically sandwiched and fixed. Specifically, the edge portion (2) of the sheet glass (3) is formed to have a length dimension substantially over the entire length, and as shown in the figure, the cross-sectional shape of the edge portion (2) in the longitudinal direction is shown. The shape of a squared "U" (a shape without one side on a hexagonal figure), and both ends of the "U" are plate glass (3)
Are formed so as to come into line contact with the front and back surfaces respectively. The outer diameter dimension is formed to be larger than the width dimension of the gap (7), and the outer diameter is set in the gap (7) with the edge portion (2) of the glass sheet (3) sandwiched therebetween, whereby the holding is performed. The sheet glass (3) can be strongly held and fixed by receiving the suppression force in the holding direction from the part (6), and the glass peripheral part can be prevented from coming off due to thermal deformation of the sheet glass (3) at the time of fire. .

The holding metal (9) is made of a metal (for example,
(Iron or stainless steel), so that it easily adapts to the environmental temperature quickly. For example, when a fire occurs, heat is also easily transmitted to the peripheral portion of the plate glass (3) that is being held. It is possible to create a state in which a temperature difference between the part and the central part hardly occurs, and to make it hard to break. When the difficulty in breaking the glass sheet (3) is converted into the stress generated at the edge, in the normal holding state where the margin (d) of the glass sheet (3) to the holding portion (6) shown in the figure is about 15 mm. , About 22 kgf / mm ² . However, in the shallow holding state in which the allowance (d) is about 10 mm, the temperature difference between the central portion and the edge portion of the sheet glass (3) becomes small, so that the stress generated by about 1 kgf / mm ² is reduced. It is about 21 kgf / mm ² .

Next, the plate glass (3) will be described.
The sheet glass (3) is formed by subjecting a soda-lime-based sheet glass to a heat strengthening process by a manufacturing method that does not use hanging metal fittings after a finishing step of an edge portion described later.

The glass sheet (3) is polished so that the end face (3a) has a curved shape protruding outward in the plane direction of the glass sheet (3) toward the middle in the thickness direction of the glass sheet (3). The boundary (3c) between the end surface (3a) and the flat surface (3b) on the front and back of the plate glass (3) is subjected to a polishing step of performing (the maximum unevenness of the polished surface is 0.05 mm or less).
Is finished more smoothly than the above-mentioned polishing step (the maximum roughness of the finished surface is 0.007 mm or less) by performing a processing and finishing step.

Specifically, the polishing step is performed as shown in FIG.
As shown in the figure, a cylindrical wheel (1
The polishing is performed by a polishing method of a flat cylindrical wheel type polishing method in which polishing is performed using the outer peripheral surface of 0), and the outer diameter of the cylindrical wheel (10) becomes smaller toward an intermediate portion in the axial direction. The end surface (3a) of the plate glass (3) to be polished is polished to a curved shape protruding outward. The outer peripheral surface of the cylindrical wheel (10) is formed as a polished portion finer than # 200.

The end face portion (3a) polished in this polishing step is finished with a surface irregularity of about 0.03 mm and has very fine irregularities. It is easy to avoid stress acting intensively.

Further, since the polishing direction in the polishing step is set along the longitudinal direction of the end face portion (3a) of the sheet glass (3), the streaks (scratch) accompanying the polishing are likewise changed at the end face portion (3). 3a) is formed along the longitudinal direction, so that concentration of thermal destructive force or the like acting along the plate surface of the glass sheet (3) can be easily avoided.

In the finishing step, as shown in FIG. 1 (b), a polishing method of a buffing type in which polishing is performed using an outer peripheral surface of a polishing belt (11) which is stretched around a biaxial rotating shaft and rotates. It is implemented by. This buff polishing is
It is also called the finest finish, and is generally polished with a belt (11) made of sheep skin, and in the polishing, an aqueous solution of cerium oxide (polishing powder having a very fine particle size) is applied to the portion to be polished. By carrying out, the surface roughness is 3
７7 μm (almost equal to the surface roughness of the front and back surfaces of the sheet glass)
, And it is possible to give a luster, and it is possible to make it difficult for internal stress to concentrate on the boundary (3c). When this is converted into strength, it is about 4 kgf / mm ² .

By the polishing step and the finishing step,
The internal stress can be made hard to concentrate on the edge portion (2) of the glass sheet (3), and in particular, the concentration of the internal stress acting along the plate surface of the glass sheet (3) can be easily avoided. As a result, it has been confirmed that it is possible to make it difficult to break even when receiving heat from a fire, and that the stress can be reduced by about 4 kgf / mm ² in terms of the stress applied by the heat strengthening treatment.

For example, in order to use a sheet glass as a class A and a class B fire door in a fire test based on the Ministry of Construction Notification No. 1125, the edge strength of the sheet glass is set to 26 kgf / mm ^2.
It is necessary to secure more than (the case where the above-mentioned margin (d) is about 15 mm). However, according to the plate glass (3) of the present embodiment, 4 kgf is caused by the holding by the holding hardware (9).
/ Mm ² , about 4 kgf with the finishing of the edge part (2)
/ Mm ² , it is only necessary to strengthen at least 18 kgf / mm ² by the heat strengthening treatment. Also, the hanging allowance (d) is 10 mm
In the shallow holding state, the temperature difference between the central portion and the peripheral portion of the sheet glass (3) is slightly reduced, so that the generated thermal stress is also reduced.
mm ² should be strengthened.

Therefore, in the heat strengthening treatment of the glass sheet (3), the heating temperature of the glass sheet (3) is 760.degree.
Even if it is not carried out at the specification of 50 mmAq, for example, the heating temperature is equal to or lower than the softening point of glass (720 to 730 ° C.)
Even when the cooling air is blown at a back pressure of 500 mmAq, a predetermined edge strength can be ensured, and the quality of the sheet glass deteriorates due to the heat strengthening treatment (the flatness of the glass surface is lost or warpage occurs). Can be prevented, the yield can be improved, and the operating cost of the heat strengthening processing equipment can be reduced.

The edge strength (surface compressive stress) of the glass sheet (3) was measured by a total reflection stress measuring method. In the total reflection stress measurement method, a prism having a slightly higher refractive index is placed on the surface of the plate glass to be measured, and a circularly polarized light beam converging at the point to be measured is incident at an angle approximately equal to the critical angle for total reflection, and reflected light observation is performed. The measurement was carried out by measuring the amount of shift between the light and dark total reflection boundary lines appearing in the field of view of the telescope on a scale calibrated by a known stress.

[Second Embodiment] As shown in FIG. 3, without using the holding hardware (9), the gap (7) between the sheet glass (3) and the holding portion (6) is In a holding structure in which the ceramic rope (S1) or the ceramic paper (S2) is packed to hold the glass sheet (3), in the normal holding state in which the margin (d) is about 15 mm, the above-mentioned glass sheet (3) is Since the edge strength of about 4 kgf / mm ² can be secured by finishing the edge portion (2), at least 22 kgf / mm ² is obtained by the heat strengthening treatment.
It is sufficient only to strengthen mm ² . Further, in the shallow holding state in which the allowance (d) is about 10 mm, the temperature difference between the central portion and the peripheral portion of the sheet glass (3) is slightly reduced, so that the generated thermal stress is also reduced. It is sufficient if reinforcement of 20 kgf / mm ² is achieved.

[Another Embodiment] Another embodiment will be described below.

<1> The finishing step is not limited to the buffing-type polishing method described in the above embodiment. For example, similarly to the above-mentioned polishing step, a polishing method using a flat cylindrical wheel type polishing method is used. (FIG. 6), combined use with a polishing method using a cup wheel (having a diamond surface or a grinding wheel attached to the wheel surface), and local heating of the edge portion (2) of the sheet glass (3). It may be performed by melting or by chemical dissolution. In short, it suffices if the maximum surface irregularity of the end face (3a) is 0.05 mm or less, and the maximum surface irregularity of the boundary (3c) is 0.007 mm or less.

<2> The end face (3) of the glass sheet (3)
a) is not limited to the above-described embodiment in which the intermediate portion in the thickness direction of the glass sheet (3) has a curved surface shape protruding outward in the surface direction of the glass sheet (3). Good. In short, it suffices that the end face portion (3a) is formed by a polishing process along its longitudinal direction and the surface maximum irregularity is finished to 0.05 mm or less.

<3> The attachment of the plate glass (3) and the sash body (5) is not limited to the above embodiment. For example, as shown in FIG. If it is fixed by using a metal elastic holding metal (9a) that makes surface contact with (5), the radiant heat to the sash body (5) is efficiently transferred from the holding metal (9a) to the periphery of the plate glass (3). It can transmit well and reduce the temperature difference between the central part and the peripheral part of the glass sheet (3),
It is possible to make it difficult to destroy. As another embodiment of the mounting state, as shown in FIG. 5, a metal elastic holding metal fitting (9b) fitted to the pressing edge (5a) of the sash body (5) and a non-combustible plate (for example, (Kycal board).

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method of finishing an edge portion of a thermally strengthened sheet glass.

FIG. 2 is a sectional view of a main part showing the fire door of the first embodiment.

FIG. 3 is a sectional view of a main part showing a fire door of a second embodiment.

FIG. 4 is a cross-sectional view showing a state of mounting a sheet glass according to another embodiment.

FIG. 5 is a cross-sectional view showing a state of mounting a glass sheet of another embodiment.

FIG. 6 is an explanatory view showing a finishing step of another embodiment.

FIG. 7 is an explanatory view showing a conventional heat-strengthened sheet glass.

[Description of Signs] 3 Sheet glass 3a End face 3b Flat face 3C Boundary

Claims (2)

(57) [Claims] 1. A thermally tempered glass plate that is subjected to a thermal tempering treatment over the entire surface, the end face (3a the end face of said plate glass (3) (3a) is, the plate glass a polishing unit for Setto (3) ) The maximum roughness of the surface due to the polishing process of moving along the longitudinal direction and polishing
Is finished to 0.05 mm or less, and the end face part (3a) and the flat part (3)
b) a boundary portion of the (3c) is maximum surface irregularity by polishing
Is 0.007 mm or less and is smoother than the end face (3a).
The surface is finished by the heat strengthening process.
Thermally tempered glass plate, wherein the compressive stress is 17~25kgf / mm ^2. 2. A method for finishing an edge portion of a heat-strengthened glass sheet which has been subjected to a heat-strengthening treatment over the entire surface, wherein a polishing portion brought into contact with an end face (3a) of the glass sheet (3) is provided. A polishing process is performed in which the polishing is performed by moving the end face (3a) along the longitudinal direction of (3) and polishing is performed so that the maximum surface unevenness is 0.05 mm or less, and then the end face (3a) is processed. And a boundary portion (3c) between the glass plate (3) and the flat portion (3b) on the front and back sides of the plate glass (3) so that the maximum surface irregularity is 0.007 mm or less and a smoother state than the end surface portion (3a). And the heat strength
Surface compression stress of 17-25 kgf / mm ²
A method for finishing an edge portion of a heat-strengthened glass sheet, characterized in that: