JPS61122132A - Production of bent glass plate - Google Patents

Abstract

PURPOSE:To coincide the curvature of the bent part of two glass plates, in high accuracy, by the process comprising the lamination of a pair of glass plates for laminated glass, the local heating of the laminated plates with local heaters placed above and below the plates, and the bending of the heated part, wherein the positions of said local heaters are restricted in a specific manner. CONSTITUTION:A pair of glass plates 1, 2 for producing a laminated bent glass, are stacked together, and local heaters are placed above and below the glass plates along the bending line of the prescribed bending part keeping a definite distances from the bending part. The widthwise heating centers A and B of the upper and the lower local heaters are positioned on the line P-P' connecting the curvature center O at the bent part after the completion of the final bending and the center C of the bending part. The plates are heated locally using the center points A and B as the heating centers, and are bent at the heated part. A laminated glass free from gaps and strains can be produced by laminating the glass plates 1, 2 bent by this process.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing folded glass sheets.

[Prior Art] Generally, laminated glass is widely used in various fields where safety is required because glass fragments do not scatter when broken. For example, a showcase, a stereo rack, a cover glass of a record player, or
When used as window glasses for various vehicles, laminated glass that is relatively sharply bent may be used due to design and structural requirements.

Conventionally, the method for producing sharply bent blank sheets of relatively sharply bent laminated glass is to stack two glass plates to form a pair, and to use the paired glass plates in a formwork for self-weight bending. A method has been used in which the glass plate is placed in a heating furnace and heated, while the bent portion of the glass plate is partially heated by a local heater, and the locally heated portion is bent.

[Problems to be Solved by the Invention] In the conventional folded glass manufacturing method, the above-mentioned local heater for partial heating is installed only on either the upper surface side or the lower surface side of the pair of glass plates. and then heat and bend only one side of the pair of glass plates, or
Also, in X, a method was adopted in which a local heater was placed between the bent portions of the pair of glass plates to heat them, and the bent portions were bent. However, with this method, the bent part of the two glass plates is not heated properly,
When two glass sheets are stacked together to make laminated glass after being bent, the curvatures of the bent parts of the two glass sheets do not match.
This has the disadvantage that gaps and distortions often occur in this area, resulting in phenomena such as foaming, cracking, and peeling.

The present invention has been made in order to eliminate the drawbacks of the conventional manufacturing method of folded glass plates for blank sheets of laminated glass, and involves stacking two glass plates and placing them on a bending die. Even when the material is bent sharper than its own weight, especially when it is bent into a J-shape or "shape" by such a method,
The curvatures of the bent parts of the two folded glass plates match, and even when these two glass plates are laminated, there is a gap,
It is an object of the present invention to provide a method for manufacturing a folded glass plate that can produce a laminated glass that is free from distortion and, therefore, does not experience phenomena such as foaming, cracking, and peeling.

[Means for solving the problem] The method for manufacturing a folded glass plate of the present invention includes stacking at least two glass plates to form a pair, and following the folding line of the desired folded portion of the pair of glass plates. , and separate local heaters are arranged on the upper surface side and the lower surface side of the bent portion at a predetermined interval, and the heating is partially increased by the local heaters so as to integrally form a pair along the bent line. In the method for manufacturing a folded glass plate in which a bent glass plate is bent, a pair of glass plates is placed on a straight line connecting the center position of the curvature of the folded part of the pair of glass plates and the center position of the folded part of the pair of glass plates and the fourth folded part. It is characterized in that the heating center point in the width direction of each local heater on the upper surface side and the lower surface side is located approximately.

FIG. 1 is a sectional view showing an example of a pair of folded glass plates manufactured by the folded glass plate manufacturing method of the present invention, and FIG. 2 is a plan view thereof.

The present invention will be explained with reference to FIGS. 1 and 2.

In the figure, two glass plates 1.2 are cut into a desired shape, chamfered, stacked, heated as a pair of glass plates 3, and bent by a local heater.

When bending, the upper surface side of the pair of glass plates 3 is placed on the straight line (P-P' line) connecting the curvature center position 0 point of the bending part and the bending part center position C point when the bending is finally completed. and the lower surface side of each local heater so that the heating center points A (upper surface side) and B (lower surface side) in the width direction are located,
It is heated and bent around center points A and B.

In addition, in FIG. 2, 01-01' is a line that connects the zero points of the centers of curvature of the bent portions of the pair of glass plates 3 in the direction of the bending line of the glass plates 3, and CI
-C1' line is a line that continues the center position C point of the above-mentioned bending part in the direction of the bending line of the glass plate 3, and AI-
The At' line is a line in which point A, which is the heating center in the width direction of the local heater placed on the upper surface side of the glass plate 3, is continuous in the direction of the bending line of the glass plate 3, and the B and -Bl' lines are the lines shown above. This is a line where point B, which is the center of heating in the width direction of the local E-tar arranged on the lower surface side of the glass plate 3, is made continuous in the direction of the bending line of the glass plate 3. The example shown in Fig. 2 is a case where the bending line is straight;
The I' line, the At-Al' line, and the B and -Bl' lines are linear.

Each of these lines corresponds to the shape of the bending line; for example, if the bending line is curved, each line is also curved.

゛By heating with the local heater arranged as described above, the central point A of the bent portion of the pair of glass plates 3,
The bending part of the glass plate 1.2 is heated to a higher temperature, so the two glass plates l
, 2 is bent symmetrically around the straight line OC and along the bending line, resulting in a uniform curved surface without distortion, and even after these two glass plates are laminated to form a laminated glass, there are no gaps or This means that phenomena such as cracking do not occur.

As a local heater that heats the glass surface, ribbon-shaped,
An electric heater in which a rod-shaped electric heater resistance wire is formed as a core material or spirally formed without a core material is desirable.

Furthermore, using such a local heater, a pair of glass plates 3
When heating the top side and the bottom side, the width of the heated part on the bottom side (the side where the heating center point B is located) is wider than the width of the heated part on the top side (the side where the heating center point A is located). If heated so that it becomes wider, the width of the bent part stretched by bending is larger on the lower side than on the upper side, so the curved surface of the bent part is formed smoothly - a more uniform curved surface with less distortion can be obtained. .

In order to make the width of the heating part on the lower surface side larger than the width of the heating part on the upper surface side, the distance from the center position C of the bending part of the setting position of one local heater.

The distance of the local heater on the bottom side should be set to be larger than the distance of the local heater on the top side.Also, when using the electric heater mentioned above as the local heater, from the center position C of the bending part Even if the distance to the set position of the local heater is almost the same on the top and bottom sides, and the width of the local heater (when heating is active) is made larger on the bottom side than on the top side, the heat radiation area will be Since the lower surface side is larger, the same effect can be obtained.

The local heaters described above are preferably disposed at the above-mentioned positions on the upper and lower surfaces of the pair of glass plates, with an interval of 5 cm to 5 c layers.

Furthermore, in the present invention, the glass plates 1 and 2 are overlapped and the bent portions of the pair of glass plates 3 are heated to a higher temperature by the above-mentioned local heater and bent. You can also sandwich another glass plate or heat-resistant ceramic fiber sheets, such as quartz glass fiber sheets, to make a pair of glass plates, and then bend the glass plates. .If the thickness of the glass plate or ceramic fiber sheet sandwiched between 2 is about the same as the thickness of the laminated interlayer film of laminated glass, and it is bent into the shape of a mouth, the area between the bending lines of the lower glass plate can be The length can be made longer than the length between the bending lines of the upper glass plate by the equivalent of the interlayer film, and by processing this, the bending part of the laminated glass due to misalignment between the upper and lower glass plates can be increased. Foaming, peeling,
It is possible to prevent the occurrence of such defects.

In manufacturing a folded glass plate according to the present invention,
Glass plate 2 cut to predetermined dimensions, chamfered, and cleaned
Stack the sheets and place them on the frame of a pair of glass silkworm type bending molds for self-weight bending. On the other hand, local heaters are arranged on the upper and lower sides of the bent portions of the pair of glass plates so that they have the positional relationship described above, along the bending line of the bent portions, and at a predetermined distance from the glass plates. do. The pair of glass plates prepared in this manner are placed in a heating furnace and the entire glass plate is heated to approximately 500°C to 800°C, and then the bent portion of the pair of glass plates is heated by the local heater 65.
It is locally heated to about 0° C. to 750° C., bent under its own weight into a predetermined bent shape by the above-mentioned gravity bending mechanism, and then taken out from the heating furnace.

When manufacturing laminated glass by laminating two glass plates manufactured in this way, the two glass plates were first peeled off and washed separately according to the usual manufacturing method for laminated glass. After sandwiching a laminated interlayer film made of polyvinyl butyral or the like between the two glass plates, the laminated glass may be manufactured by pre-pressing and then heat-pressing in an autoclave.

In particular, the method of the present invention is to form a pair of glass plates into a bending mold for self-weight bending in the shape of a mouth having bent portions on both sides as shown in FIG. 4, or with a bent portion on one side as shown in FIG. It is most suitable for the method of placing it on a frame and folding it.

[Example] As shown in Fig. 2, two rectangular glass plates l, 2 (plate thickness 2 mm, vertical dimension 50 cm) were cut into a predetermined shape and cleaned.
, lateral dimension 100 cm) on the frame of a contour type self-weight bending mold 5, and the center positions of the curvatures of the desired bent portions of the glass plates 1 and 2 and the center positions of the bent portions of these glass plates 1.2. A local heater 6.7 made of ribbon-shaped nichrome was arranged on the connected straight line. The heater 6 on the top surface of the glass plate l has a thickness of 0.21 mm, a width of 4 layers, and a length of 80 mm.
The heater 6 was placed under tension along the bent portion 4 so that the distance from the top surface of the glass plate 1 was 0.5C. In addition, as the heater 7 on the lower surface of the glass plate 2, a 2 m thick, 6 mm wide, 80 cm long heater is used, and the distance between this heater 7 and the lower surface of the glass plate is 0.8 cm + o. It was placed under tension along the bent portion 4 so that

The glass plate placed on the bending mold in this way was placed in a heating furnace and the entire glass plate was heated to 550°C, and then 180W of power was applied to the heater 6.7 to turn the heater 75.
The glass plate l is heated to 0°C and heated by this heater 6.7.
, the bent portion 4 of 2 is heated to 880°C to soften it,
Using the moment of a counterweight (not shown in the drawing) attached to the bending part of the bending mold 5, the glass plate 1.2 was sharply bent along the bending part. The curvature of each bent portion of the glass plate 1.2, which was thus sharply bent into a mouth shape, was 80R.

Glass plate bent in this way 1. Cool 2,
After washing, a polyvinyl butyral interlayer film 8 (thickness: 30 ml) was sandwiched between these glass plates 1 and 2, and this was placed in a degassing bag to be degassed and heated to 80 to 90°C in a vacuum state. After carrying out preliminary crimping, the material was taken out from the deaeration bag, placed in an O-μJ rape, and main crimping was carried out at 110-130° C. and 10 atm. In the folded laminated glass 9 manufactured in this way as shown in Figure M6, the curvatures of the folded parts of the glass plates 1 and 2 match, and the compatibility of the folded parts is good, and there is no peeling at the folded part of the laminated glass. , foaming, distortion, etc. did not occur.

[Effect of the invention] In the method for manufacturing a bent glass long plate according to the present invention,
Approximately the center point of heating in the width direction of the local heater of each glass plate is set on a straight line connecting the center position of the curvature of the bent part of the pair of glass plates and the center position of the bent part of the pair of glass plates. By heating the glass plate, it is possible to heat the glass uniformly around the center of the bend, and the curvature of the bending surfaces is the same for the two glass plates, creating an even bend without gaps or distortions. Therefore, the production of folded laminated glass that does not cause phenomena such as foaming, cracking, and peeling by laminating these two glass plates is ``T''.
fl, and it is possible to obtain a good blank folded glass for laminated glass that can be applied to a wide range of products that require relatively sharp bending angles, such as vehicles, showcases, stereo racks, cover glasses for record players, etc.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of a pair of folded glass plates manufactured by the folded glass manufacturing method of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is an explanatory diagram showing the method of the present invention, and FIG. .5 is a perspective view of another pair of folded glass plates manufactured by the method of the present invention, and Figure 6 is a cross-sectional view of an example of laminated glass laminated using the folded glass plates manufactured by the present invention. It is. 1.2---Glass plate, 3-One pair of glass plates,
0-m=center of curvature, A, B--1 heating center point, C-
-1 center position of the folded part, 4-11 folded part, 5
-m-bending type, 61--upper surface side local heater, 71--lower surface side local heater, 8--polyvinyl butyral interlayer film, 9-11 folded laminated glass straw
1st session 3rd session 4th session

Claims (4)

[Claims] (1) At least two glass plates are overlapped to form a pair, and the pair of glass plates is placed along the fold line of the desired folded part, and the folded part is spaced apart from each other by a predetermined distance on the upper and lower surfaces thereof. In the method for manufacturing a folded glass plate, a method for producing a folded glass plate is provided in which a separate local heater is arranged for each of the folded glass plates, and the pair of glass plates is integrally bent along the bending line by partially increasing heating with the local heater. Approximately the center of heating in the width direction of each local heater on the upper surface side and lower surface side of the pair of glass plates is located on the straight line connecting the center position of the curvature of the folded part of the glass plate and the center position of the folded part of the pair of glass plates. A method for manufacturing a folded glass plate, characterized in that the points are arranged so that the points are aligned. (2) When heating the bent portion of a pair of glass plates with a local heater, the width of the area heated by the local heater on the bottom side of the pair of glass plates is wider than the width of the area heated by the local heater on the top side. 2. The method of manufacturing a folded glass plate according to claim 1, wherein the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated, and the folded glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the bent glass plate is heated so that the folded glass plate is heated so that the bent glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated, and the folded glass plate is heated so that the bent glass plate is heated so that the folded glass plate is heated so that the folded glass plate is heated. (3) For each separate local heater, the distance from the center of the bent part of the pair of glass plates is larger for the local heater that heats the lower surface side of the pair of glass plates than for the local heater that heats the upper surface side. A method of manufacturing a folded glass plate according to claim 1, wherein the method is set as follows. (4) The method for manufacturing a folded glass plate according to claim 1, characterized in that the width of the local heater that heats the bottom side of the pair of glass plates is wider than the width of the local heater that heats the top side of the pair of glass plates. .