JPS60171245A - Film coated glass plate - Google Patents

Abstract

PURPOSE:To provide practical heat cracking preventing characteristics and satisfactory resistance to wind pressure to a glass plate for a window of a building or the like having a formed heat-ray reflecting film by specifying the plane compressive stress and the surface compressive stress of the peripheral part of the glass plate. CONSTITUTION:A plate of soda lime silicate glass or other glass is heat treated under proper conditions to adjust the plane compressive stress of the peripheral part of the glass plate to 50-150kg/cm<2> and the surface compressive stress to 30-100kg/cm<2>. A heat-ray reflecting film of metallic Cr or the like is then formed on the surface of the glass plate. A glass plate with >=55% sunbeam absorptance and >=10% visible light reflectance is obtd. The thickness of the glass plate is 5-12mm.. When the film coated glass plate is cracked, the crack does not grow, and the plate has little reflection strain.

Description

[Detailed Description of the Invention] The present invention does not cause thermal cracking due to temperature rise due to solar radiation heat, and also prevents cracks from propagating on their own even if cracks occur in a glass plate, and does not cause distortion of reflected images. This invention relates to a glass plate with 11 ties and ζ1 reflective coating, which is highly safe.

For example, heat ray reflective glass plates in which a coating with excellent heat ray reflection performance is formed on the surface of the glass plate are often used as window glass plates for various buildings, houses, and the like. This heat-reflecting glass plate blocks solar radiant energy by reflecting it with the heat-reflecting coating formed on the surface of the glass plate and absorbing it by itself, thereby reducing the amount of heat flowing into the room and reducing the cooling load. In addition, the heat ray reflective coating provides a unique reflective color tone, which together with its mirror effect provides a high design effect, and the anti-glare performance of the heat ray reflective coating improves the quality of the indoor environment. can get. Among this heat ray reflective glass, medium and
For high-rise buildings, window glass panels with high wind pressure resistance are recommended.
A special thickness of about 21 Jrmttr is required. However, when such a particularly thick glass plate is used, there is a risk that the glass plate itself will be thermally cracked due to an increase in temperature of the glass plate due to solar radiation heat, and there is also a disadvantage that the weight of the glass plate increases. In particular, heat-reflective glass plates that use heat-absorbing glass plates that have a high absorption rate of solar radiation heat, and heat-reflective glass plates that are constructed so that the heat-reflective coating is on the indoor side, are becoming thicker. Increased risk of thermal cracking. This thermal cracking occurs when the central part of the glass plate becomes extremely hot due to its endothermic properties, causing the glass plate to expand.
On the other hand, the periphery of the glass plate is inside the sash, so it is not exposed to sunlight, and there is also heat radiation to the sash and the frame, so the temperature remains low, so the periphery can restrict the thermal expansion of the central part. , and a tensile stress occurs, which occurs when the strength of the surrounding area can no longer withstand this tensile stress. It is possible to use air-cooled tempered glass sheets to prevent such heat cracking, but air-cooled tempered glass sheets break into many small pieces when broken, so wind-cooled tempered glass sheets are not used in high-rise buildings. If this happens, there is a danger that glass plates and fragments will fall from the windows of damaged high-rise buildings, and the heating and cooling during reinforcement processing will cause warping and distortion of the glass plate, causing reflection distortion, which is undesirable. The risk of the above-mentioned fragments falling can be somewhat alleviated by using a semi-tempered glass plate with a low degree of reinforcement to the extent that it does not break into small pieces when broken, but when manufacturing such a semi-tempered glass plate, 5
Because the glass plate is heated to about 80°C to 850°C and is rapidly cooled after heating, the glass plate tends to warp or deform.In a heat-reflective glass plate with a heat-reflecting coating formed on the surface of such a semi-tempered glass plate, heat rays are not reflected. Since the visible light reflectance of the coating is high, the warping and deformation of the glass plate becomes more noticeable as a distortion of the reflected image compared to a normal raw glass plate, which greatly reduces the quality of the glass plate.

In view of the above points, the present invention has thermal cracking prevention properties that do not cause any practical problems, and even if a crack occurs in the glass plate, the crack does not propagate by itself, and has low reflection distortion and is close to that of a raw glass plate. It was invented as a result of research with the aim of providing a glass plate that has a reflective image, is thinner and lighter than a special thick glass plate, and has sufficient wind resistance strength. The gist is that the plate thickness is 5cm to 12m.
m, and the solar ray absorption rate is at least 55%. 2. The glass plate has a visible light reflectance of 10% or more, and the plane compressive stress in the peripheral area of the glass plate is 50 to
50Kg/cat, surface compressive stress 30-100Kg/
The present invention relates to a coated glass plate characterized by being made of cn.

The present invention will be explained in more detail below.

Glass plates to which the present invention can be preferably applied include soda lime silicate, borosilicate, or alumino silicate, which are used for construction, various vehicles, and industry.
Among various glass plates such as silicate glass, soda lime silicate glass plates are the most widely used. ■) Thinner plate thickness that can reduce weight, particularly preferably 5
It has a board thickness of about 12 mm and a solar absorption rate of at least 55%, that is, an infrared absorption rate in the wavelength range of 0.781L to 2.5L, and its endothermic property makes it easily reach high temperatures, and it has a mirror surface. A glass plate having a visible light reflectance of 10% or more, on which a coating is formed that improves the effect, such as a metal coating,
Alloy coating, metal oxide coating, nitride coating, boride coating,
A transparent colorless glass plate having a smooth and flat surface, or a transparent colored glass plate such as a heat ray absorbing glass plate, coated with one or more layers of a carbide coating, other compound coatings, various paint coatings, or a combination of these coatings, Or a coated glass plate formed on an opaque colored glass plate,
For example, with heat ray reflective coating, visible ray reflective coating 4=J,
Glass plates with colored coatings, electrically conductive coatings (=J coatings), selectively permeable membranes, or heat-absorbing glass plates.

In the present invention, the central part of such a coated glass plate is heated by sunlight irradiation and becomes high temperature, but the above-mentioned thermal cracking that occurs when the peripheral part remains low temperature is suppressed. , Planar compressive stress is formed on the peripheral surface in the plane direction so that it can be used without any practical problems even if its solar absorption rate is 55% or more.
That is, the maximum plane compressive stress within the periphery of the glass plate within 2 cm inside from the end face of the glass plate is 50Kg/cnl to 150K.
g/cn! It is controlled so that it is within the range of . On the other hand, it is preferable that the plane tensile stress generated in the area inside the plane compressive stress area at the periphery of the glass plate is 60 Kg1cr& or less so as to prevent a decrease in the strength of the glass plate. Normally, the surface area of a glass plate used for architectural purposes is 1.0 m'
Therefore, the plane tensile stress generated inside the glass plate in response to the plane compressive stress formed in the peripheral area of the glass plate, especially within 2 cm from the end face, is 80 kg/- or less as described above. This level of plane tensile stress has little practical impact in terms of strength reduction.

In addition, in the present invention, the wind pressure resistance strength and thermal cracking prevention properties are improved, and on the other hand, even if a crack occurs in the glass plate, the crack does not propagate by itself and glass plate fragments do not fall, and the glass plate is In order to prevent distortion, the surface compressive stress in the cross-sectional direction of this glass plate is set at 30Kg/- to 100Kg/c.
It is preferable to set it as the range of J. This surface compressive stress is 10
If it is larger than 0Kg/cT11, when the glass plate breaks and a crack occurs, there is a risk that the crank will run on its own and pieces of the glass plate will fall, and if the glass plate exceeds 100Kg
When a surface compressive stress larger than /c++l is generated, distortion occurs in the glass plate when it is heated or cooled, which is undesirable, and when it is lower than 30 kg/-, the wind pressure strength, especially the plate thickness is 5 to 12 ma+, which is practically undesirable because it decreases. For example, the plate thickness is 81aI
m, and in the case of a glass plate with a surface compressive stress of OKg/cvd, the allowable load is 800 Kg/m', which is lower than the practically required allowable load of 1.050 Kg/m'. By applying a surface compressive stress of 30 Kg/c++i to 100 Kg/- in this manner, the wind pressure resistance strength can be increased, and the glass board can be made thinner. For example, a special thickness glass plate having a thickness of 12+am can be replaced with a glass plate of the present invention having a thickness of 101101. In addition, 30Kg/cTI as mentioned above! In order to generate a surface compressive stress of about ~100 kg/-, it is necessary to heat and cool the glass plate, but if the heat treatment is sufficient to generate a surface compressive stress in this range, it is possible to It is possible to suppress the occurrence of warpage, distortion, and other deformation on the glass plate, and it is possible to reduce reflection distortion.

Each stress value of the glass plate described above means the average value of the values measured at each point.

Note that the above-mentioned allowable load is determined by the following formula.

P: Strength when subjected to wind pressure (Kg/m') +A Area of the glass plate (m').

t: Thickness of the glass plate (am).

W: Average breaking load (Kg/d).

K: = 80° in the case of a float glass plate with a thickness of 8ffl11 Next, the present invention will be explained in comparison with a comparative example.

After heating an ordinary plate glass made of conventionally known soda-lime silicate glass to a temperature above the strain point or near the softening point, for example, e o o' c to 700°C, air is immediately applied to both sides of the glass plate. The tempered glass plate, which is sprayed and quenched to strengthen it, has a weight of 1000Kg/c.
n? It has a surface compressive stress of -1500 Kg/cn+ and a tensile stress of about 172 of the surface compressive stress at the center of the cross-sectional direction, and although it has sufficient wind pressure strength and thermal cracking prevention properties, this reinforced When the glass plate breaks, the cracks generated in the glass plate propagate by themselves4, and the fracture density is uniquely determined by the magnitude of the central tensile stress,
For example, if there are 40 to 200 pieces of 15 cm square, the thin pieces will break, and there is a high risk of glass fragments falling.

In addition, the sponsored glass plate has a surface compressive stress of 300 to 600 Kg/cnl, a central tensile stress of 250 to 400 Kg/cnl, and a surface compressive stress/central tensile stress ratio of less than 1.5, making it suitable for practical use. - Although it has good wind pressure resistance and thermal cracking prevention properties, and does not break with small pieces when broken, if a crack occurs in the glass plate, the crack will propagate by itself and extend to the edge of the glass plate. There is a danger that large pieces of glass may fall.

In addition, the present applicant has previously proposed in Japanese Patent Application No. 113H5/1987 that the glass plate has wind pressure strength and thermal cracking resistance that will not cause any problems in practical use, and that even when a crack occurs in the glass plate, the crack will self-remove. A highly safe glass plate that does not run, that is, a plate thickness of 5
■The central tensile stress is 85 to 20 mm or more and less than 10 mm.
The ratio σC/σ of the surface compressive stress σC and the central tensile stress σt is controlled to be low between 0Kg1cT11.
We have proposed a heat-treated glass plate in which t is controlled in the range of 1.5 to 3.0 and the surface compressive stress is kept low in the range of 127 to 800 Kg/cm, preferably 250 to 350 Kg/cn. This heat-treated glass plate satisfies the above-mentioned performance, but if a coating with a high reflectance of visible light such as a heat ray reflective coating is formed, the above 127 to I(0
Heat treatment to develop a surface compressive stress in the range of 0 kg/-, for example, by transporting the glass plate in a roller hearth, or by transporting it in a heating furnace while suspended by hangers, at a temperature of 580°C to 880°C. The warpage or deformation of the glass plate that occurs during the heat treatment and subsequent cooling treatment, etc., causes distortion of the reflected image, although this is not the case with tempered glass plates or semi-arcized glass plates. It was found that the quality of the product deteriorated.

For example, it is about 1/2 times smaller than normal tempered glass as mentioned above.
Figure 3 (g) shows the results of a reflective distortion measurement test conducted on two heat-treated glass sheets with a heat-reflecting coating made of Cr coating on their surfaces, which have a strength of about 4. The distortion of the reflected image was noticeable. The glass plate sample used in the measurement consisted of a roller hearth 2 having a conveyor roll 1 as shown in FIG. , a soda lime silicate φ glass plate 8 ( Dimensions: 8mmX 900mmX
1B00ms) by the conveyor roller l.
It is heated to approximately 845°C while being conveyed horizontally in the tank 2, and then the following 1. Remove it from the roller hearth with X and connect it to the first cooling outlet 4.
The glass plate 8 is cooled for 10 seconds with a cooling capacity of 180 KCal/m'·hr @°C by blowing air from the blowing port 4 onto both sides of the glass plate 8, and then the glass plate 8 is heated to about 470 degrees.
The glass plate 8 is transferred to a heat treatment furnace 5 maintained at a temperature of
When the surface temperature has decreased to about 420°C, it is taken out from the heat treatment furnace, and air is further blown in the second cooling outlet 6 (
The glass plate was further cooled, and a metal Cr film with a thickness of 200 mm was formed on the surface of the heat-treated glass plate by vacuum evaporation. It has a surface compressive stress of . (This sample will be referred to as Sample 7.) In addition, the reflection distortion measurement test was carried out using a plate-like body with a checkered pattern (20 mm in length and width).
A plate-shaped body for measuring reflection strain in which a grid of 11150 mm is formed at a pitch of 0+am) is placed vertically at a distance of 40 m from a vertically erected glass plate sample for measurement, and the image is reflected on the glass plate of the sample. The reflected image of the lattice of the plate-like body with the above-mentioned checkered pattern is photographed with a camera near the plate-like body with the checkered pattern described above, and the results are shown in drawings based on the obtained photographs. It became. (Figure 3) In contrast, the coated glass plate of the present invention has a plate thickness of 5 to 1
A glass plate with a coating has a solar absorption rate of at least 55% at 2m+a and is susceptible to thermal cracking, and has a visible light reflectance of 105 or more and is prone to noticeable distortion of the reflected image due to warping or deformation of the glass plate. However, the plane compressive stress of the surrounding area is controlled between 50Kg/cn+ and 150Kg/cn (and the surface compressive stress is also 30Kg/cn).
Since the central tensile stress is controlled between 0++ -100Kg/- and more preferably 60Kg/cJ or less, it has a practically sufficient wind pressure strength as in Samples 1 to 6 of the examples below. It has thermal cracking prevention properties, glass plate adhesive properties that prevent cracks from propagating on their own, and low reflection distortion.

In manufacturing the base glass for the coated glass plate of the present invention, the glass temperature is set at 50°C so that plane compressive stress, surface compressive stress, and central tensile stress in the peripheral area are obtained within a predetermined range.
heated to 0-580°C, preferably 540-5B°C,
Thereafter, the glass is placed in a slow cooling furnace having an atmosphere of 400-450°C, and the glass temperature is cooled to 400-480°C, preferably 420-440°C, and then heated to 250-350°C.
It is preferable to put it into a slow cooling furnace at 00°C and heat-treat it so as to cool it. In particular, when heating a glass plate, a hanger ν4 is generated, which significantly distorts the reflected image. A horizontal conveyance heating method in which heating is performed while being conveyed is preferred.

Example Six soda lime silicate glass plates (width: 1829 mff) were prepared using the glass plate heat treatment apparatus shown in Figure 2.
1. 914 mm in length) were heat-treated under the conditions shown in Table 1.

Heat ray reflective coatings made of Cr metal films of various thicknesses were formed on the surfaces of the glass plates thus obtained by vacuum evaporation. For the coated glass plate obtained in this way, visible light reflectance, large intestine radiation absorption rate 1 planar compressive stress in the peripheral area 9 surface compressive stress, central tensile stress, allowable load showing wind pressure resistance (probability of failure 1 /1000 or less), thermal cracking test results (temperature difference between the center and periphery of the glass plate until thermal cracking occurs)
, reflection distortion measurement test, and J l5-R-3206-6
-5 The destructive test results (fracture pattern) specified in
Shown in the table and drawings.

The glass sheet heat treatment apparatus shown in FIG. 2 is an example of the apparatus used for heat treatment when manufacturing the coated glass sheet of the present invention. In the figure, lO indicates the heat treatment. glass plate, 11 is a roller hearth, 1
2 is a glass plate conveying roller, 13 is a glass plate heating device, 14 is a first lehr, 15 is a second lehr, 1
B indicates the third slow cooling furnace. According to this apparatus, the glass plate IO to be heat-treated is heated to a temperature sufficient to heat-treat the glass plate while being horizontally conveyed by the conveying roller 12 in the roller hearth 11 or while being horizontally slid, for example, at 500°C. Heated to ~580°C. The glass plate IO taken out from the roller hearth 11 is placed adjacent to the outlet of the roller hearth at a temperature of 400 to 450°C.
It is moved to the first lehr 14 of
5, cooled for 200 to 300 seconds, and then transferred to a third slow cooling furnace IB with a temperature of 100 to 150 °C,
The glass plate is further slowly cooled, the generated stress is adjusted, and when the surface temperature of the glass plate reaches 150 to 200°C, it is taken out from the third slow cooling furnace 16 and left to cool to a predetermined temperature I (as in the present invention). The long-awaited glass plate is obtained.

Furthermore, regarding the glass plates of Samples 2 and 4, the results of measuring the edge compression and John at each point in the periphery are shown in FIG. The unit of f1 in the diagram is K
g/cn (is.

As shown in FIGS. 3(a) to 3(f), the film-coated glass plate of the present invention has less distortion of the reflected image than the comparative sample 7, and the raw glass plate (float glass plate, sample 8) It is recognized that the reflection distortion characteristics are close to those of the above.

In addition, as shown in MS4 diagrams (a) to (f), when a crack occurs in the coated glass plate of the present invention, self-propagation of the crack is suppressed, and there are no lines of failure. This prevents the glass plate from entering from one end to the other, reducing the risk of broken pieces of the glass plate falling from the window.

In addition, when a glass plate breaks, the risk of broken glass pieces falling from the window is reduced if the crack is prevented from propagating and the line of failure does not extend from one side of the glass plate to the other. Although it is preferable, the existence of this type of break line, which is about the size of a tree, is preferable because even if there is a line of break that extends from one side of the glass plate to the other side, there is actually little risk of broken pieces falling from the window. This is the crushing pattern of the glass plate of the present invention.

As described above, the present invention has a coating that has practically sufficient wind pressure resistance, does not cause thermal cracking, does not propagate by itself even if cracks enter the glass plate, and has a coating with low reflective distortion. A glass plate can be provided, and in particular, this coated glass plate is most suitable as a glass plate for windows and spandrels of buildings and structures such as buildings and houses. In addition, the glass plate according to the present invention has improved wind pressure strength and thermal cracking strength, and also prevents self-propagation of cracks. The 10m+w thick coated glass plate of the present invention can be used to replace the window glass plate for
The weight of the glass plate can be reduced.

[Brief explanation of the drawing]

FIG. 1 shows a schematic diagram of a heat treatment apparatus used to manufacture a glass plate of a comparative example, and FIG. 2 shows a schematic diagram of an example of a heat treatment apparatus used to manufacture a glass plate of the present invention. , FIG. 3 shows a measurement diagram of reflection distortion of coated glass plates according to the present invention and a comparative example, and FIG. 4 shows a fracture pattern diagram of a coated glass plate according to the present invention and a comparative example,
5 and 6 show measurement diagrams of plane compressive stress in the peripheral areas of samples 2 and 4. 10: Crow board, 11: Roller hearth. 12: @ feed roll, 13: heating device. 14: First lehr, 15: Second lehr. 16: Third slow cooling furnace 2 River (σ) (Q) Roro ◇r 3 ) 74 river

Claims (3)

[Claims] (1) A coated glass plate with a thickness of 5 mm to 12 mm, a solar absorption rate of at least 55%, and a visible light reflectance of 105 or more, and the planar compressive stress of the peripheral area of the glass plate is 50 kg. /crA ~150Kg/c
nl, surface compressive stress is 30Kg/cnt ~ 100Kg/
A coated glass plate characterized by being cTIl. (2) The central tensile stress of the glass plate is fiOKg/cn
1. The coated glass plate according to claim 1, wherein the glass plate has a coating thickness of 1 or less. (3) The coated glass plate according to claim 1, wherein the coating is a heat ray reflective coating.