JP2002053324A - Method for separating glass from laminated glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device by which treatment can be executed in a shorter time and at a lower cost than by conventional methods when glass is recovered from used laminated glass and further the glass can be recovered as small pieces of small dispersion so as to be easily regenerated as a raw material of not only plate glass but also other glass products. SOLUTION: Cracks are generated in the glass by subjecting the laminated glass to press treatment. After partially stripping the glass from an intermediate film, the intermediate film is heated and burned. Further, the glass at a temperature of >=500 deg.C and <=900 deg.C is thrown in water to be quenched and is reinforced and thereby stress over glass strength is generated in the glass and the glass is destroyed in a moment to obtain small pieces of the glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for separating and recovering glass from a laminated glass so that the glass can be easily recovered not only as a sheet glass but also as a raw material for other glass products. It is.

[0002]

2. Description of the Related Art Laminated glass is widely used for automobiles and buildings. It is mainly used as a windshield for automobiles, and is used for windows, doors, and inner walls of buildings for architectural purposes.

[0003] These laminated glasses are discarded after they have been used, but are rarely recycled, and are discarded as shredder dust together with rubber materials around the glass.

[0004] In order to bond the glass between two or more plate glasses, a synthetic resin film such as PVB (polyvinyl butyral) (hereinafter referred to as an intermediate film) is sandwiched between the laminated glasses. In order to reuse the glass, the glass and the membrane must be separated and only the glass must be recovered.

Conventionally, a method of separating such laminated glass by crushing the laminated glass with a crusher and separating the glass from a membrane is known. However, this method
The glass was not completely separated from the intermediate film, and a thin glass layer remained on the film surface after crushing, and the separation performance was not sufficient.

[0006] Other than the above, there are other methods for separating the laminated glass film and the glass, such as reducing the adhesive force between the glass and the film by lowering the laminated glass to -10 ° C or less, and then crushing the glass to separate the glass from the film. There is a method utilizing the property that the adhesive strength is reduced when water is contained in the interlayer film.

[0007]

However, the above-mentioned method has the following disadvantages. Ie -10 ° C
The method described below has a problem that costs are inevitably increased because a refrigeration device is required. The method of lowering the adhesive strength by including water in the intermediate film has a problem that it takes a long time for the film to be swollen with water.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is an efficient and cost-effective method for producing glass from laminated glass. It is an object of the present invention to provide a separation method and a separation apparatus characterized in that all pieces are recovered as small pieces having small variations in weight so that they can be easily regenerated as raw materials.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the laminated glass is subjected to a press treatment to cause cracks in the glass and to partially form the interlayer film. After peeling, heat the intermediate film
A method is provided in which glass is burned, and then the glass at a temperature of 500 ° C. or higher and 900 ° C. or lower is thrown into water, quenched and strengthened to generate a stress higher than the glass strength, thereby instantaneously breaking the glass and obtaining glass fragments. I do.

[0010] The present invention also provides a press zone in which a bending stress is applied to the whole and part of a laminated glass to cause cracks and partial peeling in the glass, and a heating furnace for burning a resin film of the laminated glass after pressing. At least a water tank for quenching and strengthening the glass immediately after heating, and a conveying means for conveying the laminated glass from the press zone to the water tank through a heating furnace, and the size of the glass fragments obtained by separation is 1 g. Provided is a separation device for separating glass from laminated glass, which is capable of changing the stress generated during quenching and strengthening of the glass in order to change the glass to below 0.1 g or less.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an explanatory view showing a process of a method for separating glass from a laminated glass according to the present invention. FIG. 2 shows the surface temperature Ts of the glass when the high-temperature glass is thrown into water after heating the laminated glass and burning the interlayer film, and the central temperature Tc of the laminated glass in contact with the film.
6 is a graph showing a change in the graph. FIG. 3 is a conceptual diagram showing an apparatus for separating glass from laminated glass in the present invention.

The laminated glass to be processed is first subjected to a press treatment. In this method, the glass is crushed while applying bending stress to the laminated glass with a press using an upper and lower mold,
Alternatively, there is a roll press method in which the glass is pressed while being sandwiched between a pair of upper and lower rolls and crushed. Although part of the glass is peeled off from the interlayer film by this press treatment,
The peeling rate is desirably 1% or more. The peeling rate mentioned here is
The weight percentage is obtained by subtracting the weight of the glass after pressing from the weight of the original laminated glass and dividing the result by the weight of the original laminated glass. In order to facilitate burning of the intermediate film in a later step, the pressing treatment makes the interlayer film as close as possible to air by cracking the glass.

The interlayer film easily burns when the pressed laminated glass is put in a heating furnace and heated to, for example, 700 ° C. Combustion is possible at 500 ° C. or higher, but at 800 ° C. or higher, the glass softens, making it difficult to convey the conveyor. When the glass temperature is 900 ° C. or higher, the glass is softened, and the glass becomes watery and cannot be transported. According to experiments, the time required for the interlayer to completely burn is several minutes at 700 ° C. in the case of a laminated glass for automobiles of 2 mm sheet glass + 0.7 mm interlayer film + 2 mm sheet glass.

Most interlayer films of laminated glass use polyvinyl butyral, and if completely burned, the generated gas is basically only carbon dioxide and water and is harmless. Regarding the laminated glass using an interlayer film other than polyvinyl butyral, it is necessary to check the reaction formula in advance because no harmful gas is generated, or if harmful gas is generated, it is necessary to take measures against it. Molecular formula of the polyvinyl _{butyral, - (- CH 2 CHOCOC 2} H 5 -) n
Therefore, the chemical reaction formula at the time of complete combustion of polyvinyl butyral is as follows.

(-CH ₂ CHOCOC ₂ H _5- ) n + 6n
O ₂ = 5nCO ₂ + 4nH ₂ O

When the intermediate film finishes burning, 7 mm
In the case of heating at 00 ° C., fragments of the sheet glass heated to about 700 ° C. remain. When the glass is allowed to cool outside the furnace, it is cooled to room temperature in its original shape. The large pieces remain large, which is inconvenient when the glass is later reused as a raw material for some glassware. In addition, it takes time to cool, and there is a problem in the efficiency of the treatment.

According to the present invention, by applying the strengthening technology of the sheet glass, the glass of various sizes in the heating furnace can be instantaneously made into pieces of uniform size. In other words, by throwing hot glass in the furnace into the water,
Glass receives a non-uniform and large thermal shock (= temperature difference) as compared with normal air-cooled tempering, so that it cannot withstand the stress generated in the glass and breaks itself. Cracks in fracture result in a finely branched state characteristic of tempered glass.

In general, since the magnitude of the strengthening strain of the tempered glass increases as the thickness of the sheet glass increases, the breaking energy also increases. Although 2mm sheet glass is often used for laminated glass for automobiles, it is somewhat difficult to crush it into small pieces with a thin 2mm sheet because the stress generated is small even when quenched in water. Sometimes. However, even in this case, a small branched crack is running, and can be easily broken into small pieces by applying vibration or impact.

In order to obtain a large strengthening strain, the temperature between the surface and the center should be such that when the heated sheet glass is quenched, the center of the glass is at a temperature (about 450 ° C.) which effectively stops viscous flow. What is necessary is just to manage the cooling operation so that the difference becomes the largest.

FIG. 2 is a heating / cooling curve when strengthening the sheet glass according to the present invention, where Ts indicates the surface temperature of the glass;
Tc indicates the central temperature of the glass in contact with the film. Tc at the time when the temperature of the center reaches about 450 ° C.
0, assuming that the surface temperature at that time is Ts0, ΔT = Tc0−
If Ts0 is increased, a large enhanced strain can be obtained.

Specifically, in the case of plate glass having the same thickness, ΔT increases as the glass temperature immediately before cooling increases, and ΔT increases as the cooling rate during rapid cooling increases.

The glass temperature immediately before being cooled is the glass temperature immediately before being put into water. This temperature is the same as the glass temperature when leaving the heating furnace, and the glass is taken out of the furnace and then into water. It can be managed by changing the time (seconds) before throwing.

The number of fractures when the tempered glass is broken increases as the strengthening strain increases, and the maximum fragment weight decreases. Even when a thin glass sheet having a thickness of 2 mm is heated to 800 ° C. and then rapidly cooled in water, the maximum shard weight is 0.1 g or less.

According to the present invention as described above,
After the laminated glass is pressed and the interlayer film is burned, the remaining glass of 500 ° C or higher and 900 ° C or lower is thrown into water and quenched and strengthened, thereby recovering the glass as a small piece having a small scattered fragment weight. You can do it.
And, as seen in the conventional method of separating the interlayer film and glass of laminated glass, it is not a method of using a refrigeration device or swelling the interlayer film with water, so that the cost increases and the processing time becomes longer. Without reusing glass resources.

Further, through a series of steps by the separation apparatus of the present invention, the laminated glass removed from the vehicle body or the like can be reused as a glass resource efficiently at low cost while keeping the laminated glass as it is.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a process of a method for separating glass from a laminated glass according to the present invention.

FIG. 2 shows the surface temperature Ts of the glass when the laminated glass is heated to burn the interlayer film and then several hundred degrees of glass is thrown into water, and the central temperature Tc of the laminated glass in contact with the film in the present invention. 6 is a graph showing a change in the graph.

FIG. 3 is a conceptual diagram showing an apparatus for separating glass from laminated glass in the present invention.

[Explanation of symbols]

 1: Laminated glass 2: Conveyor conveyor 3: Press A 4: Press B 5: First recovery box 6: Second recovery box 7: Heating furnace 8: Heat source 9: Water tank 10: Recovery conveyor 11: Third Collection box

Claims (3)

[Claims] 1. A method for separating and recovering glass from a laminated glass comprising a sheet glass and a synthetic resin film, wherein cracks and partial peeling occur in the glass by applying bending stress to the whole and part of the laminated glass. A method of separating glass from laminated glass, which comprises subjecting the synthetic resin film in the middle of the sheet glass to burn-off after performing a press treatment for causing the glass to be separated. 2. A method of separating and recovering glass from a laminated glass, wherein a press treatment is performed to give cracking and partial peeling to the glass by giving a bending stress to the whole and a part of the laminated glass, and to perform a pressing process in the middle of the sheet glass. Immediately after burning and removing the synthetic resin film, the glass having a temperature of 500 ° C. or higher and 900 ° C. or lower is immersed in water to quench and strengthen the glass, and generates a stress higher than the glass strength in the glass. A method for separating glass from a laminated glass, wherein the size of the crushed pieces can be changed to a required small piece weight of 1 g or less or 0.1 g or less. 3. A press zone in which a laminated glass formed by laminating a sheet glass and a synthetic resin film is pressed to generate cracks and partial peeling in the glass, and heating for burning the synthetic resin film of the laminated glass after pressing. Furnace and immediately after heating
A water tank for rapidly cooling and strengthening the glass at a temperature of not less than 00 ° C. and not more than 900 ° C .; and a conveying means for conveying the laminated glass from the press zone through the heating furnace to the water tank, and the size of the glass fragments obtained by separation. A separating device for separating glass from laminated glass, wherein a stress generated during rapid cooling and strengthening of the glass can be changed so as to change the glass thickness to 1 g or less or 0.1 g or less.