JPH09100130A - Method for bending flat plate glass and bent plate glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bend a flat plate glass to a curved form without using a forming mold and prevent the generation of reverse bending at the edge part of a bent plate glass. SOLUTION: This bending method comprises a step to apply a thermally shrinkable coating liquid 2 to one surface of a flat plate glass 1, a step to introduce the flat plate glass 1 coated with the coating liquid 2 into a heating furnace and a step to raise the temperature of the flat plate glass 1 introduced into the heating furnace at least to the softening point of the glass to form a coating film 2a on one surface of the flat plate glass 1 and to bend the heated flat plate glass 1 to a prescribed curvature by the shrinking force of the formed coating film 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of bending a flat glass sheet and a flat glass sheet by bending the flat glass sheet into a curved shape.

[0002]

2. Description of the Related Art A flat glass formed into a flat plate in a window glass manufacturing line for automobiles is bent into a desired curved shape by various molding dies. 11 (a) and 11 (b) are principle diagrams of the first conventional example of the method for bending flat glass,
As shown in (a), the flat glass 1 is placed on the upper surface of the mold 10.
1 is placed and the flat glass 11 is heated to a softening point or higher. Thereby, as shown in (b), the flat glass 11
The flat glass 11 is dropped by its own weight along the concave surface 10a of the molding die 10 to be bent into a curved shape.

FIGS. 12 (a) and 12 (b) are principle diagrams of a second conventional example of a method for bending flat glass, and as shown in FIG. 12 (a), flat glass 11 heated to a softening point is concavely shaped. It is conveyed between the mold 12a and the convex forming mold 12b,
As shown in (b), the conveyed flat glass is bent in a desired curved shape by pressing it from the vertical direction with the concave mold 12a and the convex mold 12b.

FIGS. 13 (a) and 13 (b) are principle diagrams of a third conventional example of a method for bending flat glass, and as shown in FIG. 13 (a), the flat glass 11 is transported along a transport bed 13. . As a result, as shown in (b) and (c), the flat glass sheet 11 falls into the concave surfaces 11a and 11b of the transport bed 13 and the flat glass sheet 11 is bent and formed into a curved shape.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In FIG. 13, a forming die is required to bend and form the flat glass, and since the forming die has different shapes and dimensions depending on the type of flat glass, it is necessary to provide a forming die according to the type of flat glass. Further, when changing the type of flat glass, it is necessary to replace the molding die, so it takes time to replace the molding die.

FIG. 14 is a perspective view of a bent flat glass manufactured by a conventional technique. When the flat glass is bent by a molding die, the bent glass 11 is formed along the line aa.
The entire circumference or a part of the edge portion 11c of FIG. 1 is reversely warped along the line bb. In this way, the edge part 1
Due to the occurrence of reverse warpage in 1c, the reflection distortion is disturbed, and the glass 11 cannot be bent within an allowable range.

Therefore, an object of the present invention is to bend flat glass into a desired shape without using a forming die, and to prevent the occurrence of reverse warpage at the edge of the bent flat glass, Another object of the present invention is to provide a technique capable of bending flat glass within an allowable range.

[0008]

In order to solve the above-mentioned problems, the first aspect of the present invention is to provide a step of applying a heat-shrinkable coating liquid on one surface of a flat glass, and a flat plate to which the coating liquid is applied. The step of loading the glass into the heating furnace,
The flat glass carried into this heating furnace was heated to at least the softening point to form a coating film on one surface of the flat glass, and the shrinkage force of the formed coating film raised the softening temperature. And a step of bending the flat glass into a desired curved shape. Thus, the flat glass can be bent and formed by the heat shrinkage force of the coating film formed on the surface of the flat glass. Therefore, it is possible to bend the flat glass into a curved shape without using a molding die, and it is possible to prevent reverse warp from occurring at the edge portion of the flat glass that has been bent.

According to a second aspect, a step of drying the coating liquid is added between the applying step and the carrying-in step of the first aspect.
Thereby, the coating liquid applied to the flat glass can be dried layer by layer, so that a multilayer coating film can be formed on the surface of the flat glass.

According to a third aspect of the present invention, after the step of bending the flat glass whose temperature is raised to the softening point by the contracting force of the coating film, the flat glass is pressed with a press die having concave and convex surfaces to obtain a desired curved shape. A step of bending is added. In this way, after the flat glass is preliminarily bent and shaped by the heat shrinkage force of the coating film, the flat glass is bent into a desired curved shape by using a molding die, thereby forming an edge of the flat and bent glass. It is possible to prevent the occurrence of reverse warp in the portion, and it is possible to bend the flat glass within an allowable range.

According to a fourth aspect, a step of drying the coating liquid is added between the coating step and the carrying-in step of the third aspect.
Thereby, the coating liquid applied to the flat glass can be dried layer by layer, so that a multilayer coating film can be formed on the surface of the flat glass. As described above, the heat-shrinkable coating film can be used as a functional thin film by forming a multilayer coating film.

According to a fifth aspect of the present invention, there is provided a heat-shrinkable coating film formed on one surface of a flat glass plate to bend the flat glass plate by a contracting force, and a curved flat glass plate bent by the shrinking action of the heat-shrinkable coating film film. Consists of. Thus, the flat glass can be bent and formed into a curved shape without using a forming die, and it is possible to prevent reverse warp from occurring in the edge portion of the flat and formed glass.

According to a sixth aspect of the present invention, there is provided a heat-shrinkable coating film formed on one surface of a flat glass plate, which bends the flat glass plate by a shrinking force, and a press die which is bent by the shrinking action of the heat-shrinkable coating film. And a curved plate glass bent into a desired shape. As a result, the flat glass can be bent by the heat shrinkage effect of the coating film and can be formed into a curved shape by using a (press) forming die, and the reverse warp may occur at the edge portion of the bent flat glass. Can be prevented.

A seventh aspect of the invention is characterized in that the heat-shrinkable coating film has a multi-layer structure. As described above, the heat-shrinkable coating film can be used as a functional thin film by forming a multilayer coating film.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.

FIGS. 1 (a) to 1 (e) are process explanatory views of a flat glass bending method and a bent glass plate according to a first embodiment of the present invention. (A) shows the flat glass 1 before applying a coating liquid. In (b), the coating liquid 2 is applied to the surface of the flat glass 1. As the coating liquid 2, a sol-gel composition containing an organic silicon compound as a main component is used. The coating liquid 2 has heat shrinkability. The coating liquid 2 is applied so that the coating film thickness after heat treatment is in the range of 50 nm to 1000 nm.

Preferred organic silicon compounds (Si-based alkoxides, etc.) are tetraalkoxysilanes represented by Si (OR) ₄ , and so-called silane coupling agents such as SiR ' _4-n (OR) _n. Applied to. However, R is a methyl group, an ethyl group, a propyl group, or a butyl group, and R'is a methyl group, an ethyl group, a propyl group, a vinyl group, a γ-chloropropyl group, a γ-aminopropyl group, and a γ group.
-Methacryloxypropyl group or γ-mercaptopropyl group, n is an integer of 1 to 3. Further, the total solid content of the organic silicon compound and the metal alkoxide is 3 to 15%.
By diluting with an organic solvent so that it falls within the range of
Adjust the viscosity of the coating solution before use.

The organic medium used for adjusting the viscosity depends on the coating method described later. For example, as the organic solvent for the gravure coating method, the flexographic printing method and the roll coating method, an alcohol having a boiling point of 100 ° C. or higher is used. Boiling point (boiling point of 100 to 150 ° C) or high boiling point (150) of ethers, ether alcohols, and glycols
It is desirable to include at least one solvent having a boiling point (above ° C).

Since storage stability varies depending on the solvent, among the above solvents, diacetone alcohol, tetrahydrofurfuryl alcohol, ethyl cellosolve, butyl cellosolve, cellosolve acetate, diethylene glycol monoethyl ether, hexylene glycol, diethylene glycol. , Tripropylene glycol is preferred. Furthermore, the viscosity of the composition used in the gravure coating method and the flexographic printing method is 20 cps (25 ° C.).
If it exceeds the above range, a standing wave is likely to occur on the liquid surface on the coating roll, causing unevenness of the film thickness and prolonging the leveling time. Therefore, it is desirable to adjust the amount of the solvent to keep the viscosity of the composition at 20 cps or less. .

By mixing a refractive index adjusting agent (for example, ZrO ₂ , TiO ₂ , CeO ₂ ) with the coating liquid 2, it is possible to adjust the refractive index of the coating film when the coating film is baked. In this way, by adjusting the refractive index of the coating film, the reflectance can be made the same as that of the flat glass. In this way, by making the refractive index of the coating film the same as the refractive index of the flat glass, the boundary between the coating film and the flat glass cannot be seen even when the coating film is partially formed on the flat glass. You can In addition, by using a specific refractive index adjusting agent, it is possible to cut ultraviolet rays and the like with a coating film and obtain antiglare properties. Z
As a raw material of rO ₂ , as zirconium alkoxide, tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium, tetra n-propoxyzirconium, tetraisoptoxyzirconium, tetra n-ptoxyzirconium, tetras
Zirconium tetraalkoxides such as ec-ptoxy zirconium and tetra t-ptoxy zirconium are preferred.

As the raw material of TiO ₂ , titanium alkoxide, titanium acetylacetonate, and titanium carboxylate are used. As this titanium alkoxide, Ti (OR) ₄ (R is an acetyl group having up to 4 carbon atoms)
In consideration of reactivity, titanium isopropoxide and titanium butoxide are preferable. As a raw material of CeO ₂ , in addition to cerium organic compounds such as cerium alkoxide, cerium acetylacetonate, and cerium carboxylate, cerium inorganic compounds such as nitrates, chlorides, and sulfates can be considered, but they are stable and easily available. Preference is given to using nitrates and acetylacetonates.

As a method of applying the coating liquid on the surface of the flat glass, for example, a spin coating method, a dip coating method, a spray coating method, a printing method and the like are known. In particular, in the printing method, a gravure coating method, a flexographic printing method, a roll coating method, a screen printing method and the like are preferable since the composition (coating liquid) can be efficiently used.

In (c), the coating liquid 2 applied to the surface of the flat glass 1 is dried. The drying time is, for example, at a temperature of 80 ° C. for 30 minutes. In this drying step, the coating liquid 2 is dried and the coating film 2
a is formed, and at the same time, the coating film 2a is thermally shrunk. On the other hand, since the flat glass 1 has not been heated to the softening point yet, the contraction of the coating film 2a causes the flat glass 1 to shrink.
It is stopped by. Therefore, a residual stress F ₁ that tends to shrink is generated in the coating film 2a. However, in this drying step (drying at a temperature of 80 ° C. for 30 minutes), the residual stress F ₁ generated is relatively small because the coating film 2a is not sufficiently heat-contracted.

In (d), after the coating film 2a is formed on the surface of the flat glass 1, the flat glass 1 is carried into a heating furnace such as a horizontal transfer furnace (not shown), and the flat glass 1 is heated to the temperature T. Heat to ₁ (eg, about 400 ° C.).
Thus, when the flat glass 1 is heated to the temperature T ₁ , the film performance of the coating film 2a, that is, the coating film 2
It is possible to sufficiently enhance the strength of a, the adhesion performance between the coating film 2a and the flat glass 1, and the like. Further, when the heating temperature rises to T ₁ , the coating film 2a is sufficiently heat-contracted, but since the flat glass 1 is not yet heated to the softening point, the flat glass 1 prevents the flat contraction of the coating film 2a. . Therefore, a relatively large residual stress F ₂ that tends to shrink is generated in the coating film 2a.

In (e), the flat glass 1 in the heating furnace is heated to a temperature T ₂ . The temperature T ₂ is a temperature at least exceeding the softening point of the flat glass 1, and is about 570 as an example.
It is selected in the range of ℃ to 700 ℃. In this way, by heating the flat glass 1 to the softening point, the flat glass 1 is bent into a desired curved shape by the contracting force of the residual stress F ₂ in the coating film 2a.

As described above, the heat shrinkage force of the coating film 2a required for deforming the flat glass 1 into a curved shape depends on the composition of the coating film 2a (type of alkoxide and solvent), the thickness of the coating film 2a, and It is determined by the heating temperature factor. Actually, in order to form the flat glass 1 into a desired shape, in addition to manipulating these factors, the coating portion of the coating film 2a, the coating area, and the cooling method such as simultaneous upper and lower cooling and upper and lower one-side cooling are adjusted. It becomes possible by doing.

Although the coating film 2a is formed on the entire surface of the flat glass plate 1 in FIG. 1, the present invention is not limited to this, and the coating film 2a is formed on a part of the flat glass plate 1. Good.

FIGS. 2A to 2G are process explanatory views of the second embodiment of the method for bending a flat glass according to the present invention. Since the steps shown in FIGS. 2A to 2D are the same as the steps shown in FIGS. 1A to 1D of the first embodiment, description thereof will be omitted.

In FIG. 2D, as in FIG. 1D, the flat glass 1 in the horizontal transfer furnace is heated to the temperature T ₂ . The temperature T ₂ is a temperature at least above the softening point of the flat glass 1, and is selected in the range of approximately 570 ° C. to 700 ° C. as an example. In this way, by heating the flat glass 1 to the softening point, the residual stress F in the coating film 2a is increased.
_The flat glass 1 is preliminarily bent and shaped by a contracting force of ₂ .

In (f), the flat glass 1 preliminarily bent and molded in the previous step is processed into a concave mold 3 and a convex mold 4.
Transport to In (g), the flat glass 1 conveyed between the concave mold 3 and the convex mold 4 is bent into a desired curved shape by the concave mold 3 and the convex mold 4.

In the first and second embodiments, the case where one layer of the coating film 2a is formed on the surface of the flat glass 1 has been described.
It is also possible to form it.

In the first and second embodiments, the case where the drying process for drying the coating liquid is independent before heating in the horizontal transfer furnace has been described. However, when the coating film is a single layer, the coating liquid is dried. It is also possible to simultaneously perform the drying of the coating liquid and the heating to the temperatures T ₁ and T ₂ in the horizontal transfer furnace without separating the drying step.

[0033]

Embodiments of the present invention will be described below. Examples 1 to 3 of the first embodiment will be described based on Table 1.

[0034]

[Table 1]

The coating liquid of Example 1 shown in Table 1 is
Si-based alkoxide [Si (OC
H ₃ ) ₄ ] was used and a Zr-based alkoxide [ZrO ₂ ] was mixed as a substance for adjusting the refractive index. In this case, S
The solid content ratio of i (OCH ₃ ) ₄ and ZrO ₂ is 1: 0.16.
It is. This coating liquid was applied to the entire surface of one side of the flat glass by the gravure coating method so that the coating film thickness after firing was about 200 nm. Next, after drying the coating liquid, the flat glass is heated to a predetermined temperature (in the range of about 570 ° C. to 700 ° C.) in a horizontal transfer furnace,
The flat glass was bent into a curved shape by the heat shrinkage force of the coating film.

The results are shown in FIG. FIG. 3 is an end view of the bent plate glass according to the first embodiment of the present invention, in which the edge part 1a of the flat glass 1 is bent so that the edge part 1a does not warp and the edge part 1a smoothly falls. I understand.

In addition, the coating liquid of Example 2 shown in Table 1 contains the Si-based alkoxide [Si (OC
₂ H ₅ ) ₄ ] and Zr is used as a substance for adjusting the refractive index.
The system alkoxide [ZrO ₂ ] was mixed. in this case,
The solid content ratio of Si (OC ₂ H ₅ ) ₄ and ZrO ₂ is 1: 0.1.
6. Also in the case of Example 2, the coating liquid was applied in the same manner as in Example 1 so that the coating film thickness after firing was about 200 nm.
Was applied to the entire surface on one side of the flat glass by the gravure coating method. Next, after drying the coating solution, the flat glass is placed at a predetermined temperature (about 570 ° C.
The flat glass was bent into a curved shape by heating up to 700 ° C.).

FIG. 4 shows the results. FIG. 4 is an end shape diagram of a bent sheet glass according to Example 2 of the present invention. As with FIG. 3, the edge portion 1a of the flat glass 1 does not cause reverse warp so that the edge portion 1a smoothly falls. It can be seen that it is bent.

Further, the coating liquid of Example 3 shown in Table 1 contains the Si-based alkoxide [Si (i
-OC ₃ H ₇ ) ₄ ] was used, and a Zr-based alkoxide [ZrO ₂ ] was mixed as a substance for adjusting the refractive index. In this case, the solid content ratio of Si (i-OC ₃ H ₇ ) ₄ and ZrO ₂ is 1: 0.16. In the case of Example 3 as well, as in Example 1, the coating liquid was applied to the entire surface of one side of the flat glass by the gravure coating method so that the coating film thickness after firing was about 200 nm. Next, after drying the coating liquid, the flat glass is heated at a predetermined temperature (about 57
The flat glass was bent into a curved shape by heating to a range of 0 ° C. to 700 ° C.).

The results are shown in FIG. FIG. 5 is an end shape diagram of a bent sheet glass according to Example 3 of the present invention. As with FIG. 3, the edge portion 1a of the flat glass 1 does not cause reverse warp so that the edge portion 1a smoothly falls. It can be seen that it is bent.

Next, Examples 4 to 6 of the second embodiment will be described based on Table 2.

[0042]

[Table 2]

The coating liquid of Example 4 shown in Table 2 was
An ethyl silicate solution [SiO ₂ ] was used as a main component, and a Zr-based alkoxide [ZrO ₂ ] was mixed as a substance for adjusting the refractive index. In this case, SiO ₂ and ZrO ₂
And the solid content ratio is 1: 0.16. This coating liquid was applied to the entire surface of one side of the flat glass by the gravure coating method so that the coating film thickness after firing was about 200 nm. Next, after drying the coating liquid,
Flat glass in a horizontal transfer furnace at a predetermined temperature (about 570 ° C to 70 ° C)
Then, the flat glass was bent and formed into a preliminary curved shape by the heat shrinkage force of the coating film. Then, the flat glass was conveyed between the concave mold and the convex mold, and the flat glass was bent into a desired curved shape by the concave mold and the convex mold.

The results are shown in FIG. FIG. 6 is a shape diagram of a bent plate glass according to Example 4 of the present invention, in which the edge portion 1a of the flat glass 1 does not have a reverse warp and the edge portion 1
It can be seen that the "a" is bent so as to drop smoothly. On the other hand, in the comparative example in which the coating film was not formed on the flat glass but was heated to the softening point in the horizontal conveying furnace, and then pressed by the mold having the concave surface and the convex surface to be bent into a curved shape, the glass was As indicated by the broken line, the edge portion 5a of the flat glass 5 is reversely warped, and reflection distortion occurs from the center of the glass 5 to the edge portion 5a.

The coating liquid of Example 5 shown in Table 2 is
Using the same main component as in Example 4, a Ti-based alkoxide [TiO ₂ ] was mixed as a substance for adjusting the refractive index. In this case, the solid content ratio of SiO ₂ and TiO ₂ is 1:
It is 0.08. This coating liquid was applied to the entire surface of one side of the flat glass by the gravure coating method so that the coating film thickness after firing was about 200 nm. Next, after drying the coating liquid, the flat glass is heated to a predetermined temperature (in the range of about 570 ° C to 700 ° C) in a horizontal conveyance furnace, and the flat shrinkage of the flat glass is caused by the heat shrinkage force of the coating film. Bent and molded. Then, the flat glass was conveyed between the concave mold and the convex mold, and the flat glass was bent into a desired curved shape by the concave mold and the convex mold. The result is shown in FIG. FIG. 7 is a shape diagram of a bent sheet glass according to Example 5 of the present invention, and the same effect as that of Example 4 is obtained.

The coating liquid of Example 6 shown in Table 2 is
The same main component as in Examples 4 and 5 was used, and a Ce-based alkoxide [CeO ₂ ] was mixed as a substance for adjusting the refractive index. In this case, the solid content ratio of SiO ₂ and CeO ₂ is 1:
It is 0.09. This coating liquid was applied to the entire surface of one side of the flat glass by the gravure coating method so that the coating film thickness after firing was about 200 nm. Next, after drying the coating liquid, the flat glass is heated to a predetermined temperature (in the range of about 570 ° C to 700 ° C) in a horizontal conveyance furnace, and the flat shrinkage of the flat glass is caused by the heat shrinkage force of the coating film. Bent and molded. Then, the flat glass was conveyed between the concave mold and the convex mold, and the flat glass was bent into a desired curved shape by the concave mold and the convex mold. The result is shown in FIG. FIG. 8 is a shape diagram of a bent sheet glass according to Example 6 of the present invention.
You get the same effect as.

The second embodiment will be described in detail in Examples 7 to 11. In the case of Example 7, the coating liquid is prepared by the following steps. First, 56.0 g of ethyl acetoacetate was added to 82.5 g of tetra-n-butoxyzirconium to give 30
Stir for one minute at room temperature to form ethyl zirconium butoxydiacetoacetate. Next, to this ethyl zirconium butoxydiacetoacetate, 425.9 g of butyl cellosolve,
Hexylene glycol (250 g), tetraethoxysilane pentamer (Colcoat, product name "ethyl silicate 40") 43.0 g, 0.01 N hydrochloric acid (5.2 g) were sequentially added, and the mixture was stirred at room temperature for 2 hours. Prepare the coating liquid of. This prepared coating liquid is Si / Zr
The molar ratio of Si / Zr becomes 4/3, and the refractive index of the coating film is adjusted by adjusting the amount of Zr-based alkoxide mixed.

Next, the prepared coating liquid is applied to the entire surface of one side of the flat glass by the gravure coating method. As the flat glass, soda lime glass having a plate thickness of 3.4 mm is used. Then, the coating liquid applied to the flat glass was dried at 250 ° C. for 30 minutes to obtain a coated glass. Then, with the coating surface facing upward, the flat glass was preliminarily bent and molded by heating at a predetermined temperature (in the range of about 570 ° C to 700 ° C) in a horizontal transfer furnace,
The preformed glass was pressed with a mold having concave and convex surfaces to bend it into a desired curved shape. The coating film thickness in this case is 50 nm.

The glass with a coating film of Example 7 was
Similar to Examples 4 to 6, the edge portion was not warped, and was bent so as to be smoothly dropped to obtain good reflection distortion. In addition, the reflection color reflected by the glass with a coating film has a neutral color tone, and further, this coating film has a good surface hardness as a result of inspection by a taper abrasion test, and has acid resistance, alkali resistance and boil resistance. Was also good.

On the other hand, without forming a coating film on the flat glass, after heating to a softening point in a horizontal conveying furnace, a concave surface,
The glass, which was pressed by a mold having a convex surface and was bent into a curved shape, had an edge warped reversely, and the reflection strain from the glass center to the edge was disturbed.

In the case of Example 8, the coating film thickness is 15
Although the thickness was set to 0 nm, the same effect as in Example 7 in which the coating film thickness was 50 nm was obtained.

In the case of Example 9, the coating film thickness is 30
Although the thickness was set to 0 nm, the same effect as in Example 8 in which the coating film thickness was 150 nm was obtained.

In the seventh to ninth embodiments, the case where the coating film is a single layer has been described, but the same effect can be obtained by forming the coating films in multiple layers as in the tenth and eleventh embodiments. In this way, by forming a multilayer coating film, it can be used as an antireflection film. FIG. 9 is an enlarged view of an essential part of a bent sheet glass according to Example 10 of the present invention, showing a state in which a three-layer coating film is formed on the glass. Hereinafter, Example 10 will be described. The coating solution A of Example 10 is prepared by the following steps. First, Tetra n-
Ethyl acetoacetate 2 to 41.3 g of butoxyzirconium
Add 8.0 g and stir for 30 minutes at room temperature to form ethyl zirconium butoxydiacetoacetate. Next, to this ethyl zirconium butoxydiacetoacetate, 425.9 g of butyl cellosolve, 250 g of hexylene glycol,
Tetraethoxysilane pentamer (Colcoat, product name "ethyl silicate 40") 43.0 g, 0.01N
Hydrochloric acid (5.2 g) was added successively and the mixture was stirred at room temperature for 2 hours to prepare coating liquid A of Example 10.

Next, the coating solution B of Example 10 is prepared in the following steps. First, 164.9 g of tetra-n-butoxyzirconium was added to 111.9 of ethyl acetoacetate.
Add g and stir for 30 minutes at room temperature to form ethyl zirconium butoxydiacetoacetate. The prepared coating liquid A has a Si / Zr molar ratio of Si / Zr =
It is a low-refractive-index coating liquid that becomes 8/3. Next, to this ethyl zirconium butoxydiacetoacetate, 425.9 g of butyl cellosolve and 250 of hexylene glycol were added.
g, tetramer of tetraethoxysilane (made by Colcoat,
Product name "ethyl silicate 40") 43.0 g, 0.0
5.2 g of 1N hydrochloric acid was added sequentially and stirred at room temperature for 2 hours to form a coating solution B of Example 10. This prepared coating liquid B has a Si / Zr molar ratio of
It is a medium-refractive-index coating liquid with Si / Zr = 2/3.

Next, as shown in FIG. 9, the prepared coating liquid A 5 was applied to a flat glass 1 (soda lime glass having a thickness of 3.4 mm) by a gravure coating method.
The coating A liquid 5 applied to the entire surface of one side of the above and applied to the flat glass 1 is dried at 250 ° C. for 30 minutes. Then
The coating B liquid 6 is applied to the surface of the coating A liquid 5 by the gravure coating method, and the applied coating B liquid 6 is dried at 250 ° C. for 30 minutes. Subsequently, the coating A liquid 7 is applied to the surface of the coating B liquid 6 by the gravure coating method, and the applied coating A liquid 7 is dried at 250 ° C. for 30 minutes. This allows
Three layers of coating film 5 on one side of the flat glass 1,
Films 6 and 7 are formed. This coating film is a three-layer (glass / A film 5 / B film 6 / A film 7 / air) type antireflection film.

Next, with the coating films 5, 6, and 7 facing upward, the flat glass was preliminarily bent by heating in a horizontal transfer furnace in the range of about 570 ° C. to 700 ° C., and then preformed. The glass 1 was pressed into a desired curved shape by pressing it with a mold having concave and convex surfaces. The glass 1 of Example 10 bent and formed in this manner was bent and formed so that the edge portions of the glass were smoothly dropped in the same manner as in Examples 7 to 9. In addition, the coating films 5, 6, and 7 of Example 10-3
The layer thickness is 300 nm.

FIG. 10 is an enlarged view of an essential part of a bent sheet glass according to Example 11 of the present invention, showing a state in which a three-layer coating film is formed on the glass. Example 10 as described above
In the above, the case where a Zr-based alkoxide was used as the refractive index adjusting substance of the coating film to form a three-layer coating film was described. However, as in Example 11, Ti was used as the refractive index adjusting substance of the coating film. The same effect as in Example 10 was obtained by using the alkoxides of the Ce type and the Ce type. Example 11 will be described below.

The coating solution A of Example 11 is prepared by the following steps. First, 161.9 g of tetra-n-butoxyzirconium is added with 111.9 g of ethyl acetoacetate and stirred at room temperature for 30 minutes to form ethyl zirconium butoxydiacetoacetate. Next, butyl cellosolve 425.9 was added to this ethyl zirconium butoxydiacetoacetate.
g, hexylene glycol 250 g, tetraethoxysilane pentamer (manufactured by Colcoat, product name “ethyl silicate 40”) 43.0 g, and 0.01 N hydrochloric acid 5.2 g are sequentially added, and the mixture is stirred at room temperature for 2 hours. Formulate coating A liquid of Example 11. The prepared coating liquid A is a medium refractive index coating liquid having a Si / Zr molar ratio of Si / Zr 2/3.

Then, the coating solution B of Example 11 is prepared in the following steps. First, ethyl cellosolve 5
Acetylacetone 8.9g and tetraisopropoxy titanium 12.6g are added to 9.8g, and it agitates at 40 ° C. Next, tetraethoxysilane pentamer 2.0 g, 0.01
Add 0.2 g of N hydrochloric acid and stir at 40 ° C. for 4 hours. Then add 13.5 g of cerium nitrate hexahydrate and add 40 ° C.
After stirring for 2 hours at room temperature, 3 g of trimethylolpropane triacrylate.6 ethylene oxide unit adduct (TMPTE E06) is added and stirred to prepare coating B solution of Example 8. The prepared coating liquid B has a Si / Ti / Ce molar ratio of Si / Ti / C
It is a high-refractive-index coating liquid with e = 3/10/7.

Next, as shown in FIG. 10, the prepared coating liquid A 8 was applied to the flat glass 1 (soda lime glass having a thickness of 3.4 mm) by the gravure coating method.
The coating A liquid 8 applied to the entire surface of one side of the above is dried at 250 ° C. for 30 minutes. Then
The coating B liquid 9 is applied to the surface of the coating A liquid 8 by the gravure coating method, and the applied coating B liquid 9 is dried at 250 ° C. for 30 minutes. As a result, two layers of coating films 8 and 9 are formed on the entire surface of the flat glass 1 on one side. This coating film is a two-layer (glass 1 / A film 8 / B film 9 / air) type antireflection film.

Next, the coating films 8 and 9 are turned upward, and the flat glass 1 is preliminarily bent by heating in a horizontal transfer furnace in the range of about 570 ° C. to 700 ° C., and then the preformed glass. 1 was pressed with a mold having a concave surface and a convex surface to form a desired curved shape. The glass 1 of Example 11 bent and formed as described above was bent and formed so that the edge portion of the glass was smoothly dropped in the same manner as in Example 10.
The thickness of the two layers of the coating films 8 and 9 of Example 11 is 250 nm.

[0062]

The present invention has the following effects due to the above configuration. According to the first aspect, the flat glass can be bent by the heat shrinkage force of the coating film formed on the surface of the flat glass. Therefore, since the flat glass can be bent into a curved shape without using a forming die, it is not necessary to provide a forming die according to the type of glass. Furthermore, since it is not necessary to replace the mold when changing the type of glass to be bent, it is not necessary to replace the mold. Further, by bending the flat glass by the heat shrinkage force of the coating film, it is possible to prevent the occurrence of reverse warp at the edge portion of the bent glass.

In the second aspect, a step of drying the coating liquid is added between the coating step and the carry-in step. Thus, the coating liquid applied to the flat glass can be dried layer by layer, so that a multilayer coating film can be formed on the surface of the flat glass.

According to a third aspect of the present invention, the flat glass is preliminarily bent and formed by the heat shrinkage force of the coating film, and then the glass is bent and formed into a desired curved shape by using a forming die.
It is possible to prevent the occurrence of reverse warpage at the edge of the bent glass, and the reflection distortion becomes good. Also,
The glass can be bent within an acceptable range. Further, the flat glass is preliminarily bent and formed by the heat shrinkage force of the coating film, and then the glass is bent and formed into a desired curved shape by using a forming die, thereby facilitating the bending and forming of the glass by the forming die. .

In the fourth aspect, a step of drying the coating liquid is added between the coating step and the carry-in step. Thus, the coating liquid applied to the flat glass can be dried layer by layer, so that a multilayer coating film can be formed on the surface of the flat glass. As described above, the heat-shrinkable coating film can be used as a functional thin film by forming a multilayer coating film.

According to a fifth aspect of the present invention, the heat-shrinkable coating film bends the flat glass by the shrinkage force, and the curved plate glass bent by the shrinking action of the heat-shrinkable coating film. Thus, the flat glass can be bent and formed into a curved shape without using a forming die, and it is possible to prevent reverse warp from occurring in the edge portion of the flat and formed glass.

According to a sixth aspect of the present invention, a heat-shrinkable coating film is formed on one surface of a flat glass plate to bend the flat glass plate by a shrinking force, and a press die after being bent by the shrinking action of the heat-shrinkable coating film. And a curved plate glass bent into a desired shape. As a result, the flat glass can be bent by the heat shrinkage effect of the coating film and can be formed into a curved shape by using a (press) forming die, and the reverse warp may occur at the edge portion of the bent flat glass. Can be prevented.

Since the heat-shrinkable coating film has a multi-layer structure, the heat-shrinkable coating film can be used as a functional thin film by forming a multi-layer coating film.

[Brief description of the drawings]

FIG. 1 is a first method for bending a flat glass according to the present invention.
Process explanatory drawing of embodiment

FIG. 2 is a second example of the method for bending a flat glass according to the present invention.
Process explanatory drawing of embodiment

FIG. 3 is a diagram showing an end shape of a bent glass sheet according to Example 1 of the present invention.

FIG. 4 is an end view of a bent sheet glass according to a second embodiment of the present invention.

FIG. 5 is an end view of a bent sheet glass according to a third embodiment of the present invention.

FIG. 6 is a shape diagram of a bent sheet glass according to Example 4 of the present invention.

FIG. 7 is a shape diagram of a bent sheet glass according to Example 5 of the invention.

FIG. 8 is a shape diagram of a bent sheet glass according to Example 6 of the present invention.

FIG. 9 is an enlarged view of a main part of a bent sheet glass according to example 10 of the invention.

FIG. 10 is an enlarged view of a main part of a bent sheet glass according to example 11 of the invention.

FIG. 11 is a principle diagram of a first conventional example of a conventional flat glass bending method.

FIG. 12 is a principle diagram of a second conventional example of a conventional flat glass bending method.

FIG. 13 is a principle diagram of a third conventional example of a conventional flat glass bending method.

FIG. 14 is a perspective view of a bent sheet glass manufactured by a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flat glass, 2 ... Coating liquid, 2a ... Coating film, 3 ... Concave mold, 4 ... Convex mold

Claims (7)

[Claims] 1. A step of applying a heat-shrinkable coating liquid to one surface of a flat glass, a step of loading the flat glass coated with the coating solution into a heating furnace, and a step of loading the flat glass into the heating furnace. From the process of heating the flat glass to at least the softening point to form a coating film on one surface of the flat glass and bending the flat glass into a desired curved shape by the shrinking force of the formed coating film. Method for bending flat glass. 2. A step of applying a heat-shrinkable coating liquid to one surface of a flat glass plate, a step of drying the coating liquid, and a step of loading the flat glass plate with the dried coating liquid into a heating furnace. A step of forming a coating film by raising the temperature of the flat glass carried into the heating furnace to at least the softening point, and bending the flat glass into a desired curved shape by the contracting force of the formed coating film. And a method of bending a flat glass. 3. A step of applying a heat-shrinkable coating liquid to one surface of flat glass, a step of loading the flat glass coated with the coating solution into a heating furnace, and a step of loading the flat glass into the heating furnace. A step of forming a coating film by heating the flat glass to at least the softening point, preliminarily bending the flat glass by the shrinking force of the formed coating film, and the preliminarily bent flat plate. A method for bending flat glass, comprising the steps of pressing glass with a press die having concave and convex surfaces and bending the glass into a desired curved shape. 4. A step of applying a heat-shrinkable coating solution to one surface of flat glass, a step of drying this coating solution, and a step of loading flat glass with the dried coating solution into a heating furnace. A step of forming a coating film by raising the temperature of the flat glass carried into the heating furnace to at least the softening point, and preliminarily bending and shaping the flat glass by the contracting force of the formed coating film, A method of bending a flat glass sheet, comprising the steps of pressing the preliminary flat glass sheet with a press die having concave and convex surfaces to form a desired curved shape. 5. A bend composed of a heat-shrinkable coating film formed on one surface of a flat glass plate to bend the flat glass plate by a contracting force, and a curved flat glass plate bent by the shrinking action of the heat-shrinkable coating film film. Flat glass. 6. A heat-shrinkable coating film which is formed on one surface of a flat glass and bends the flat glass by a shrinking force, and a heat-shrinkable coating film which is bent by the shrinking action of the heat-shrinkable coating film and is then pressed into a desired shape. A bent flat glass consisting of a curved flat glass bent into a shape. 7. The bent sheet glass according to claim 5, wherein the heat-shrinkable coating film has a multi-layer structure.