JPS6222936B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for pre-pressing laminated glass.

Laminated glass, which is made by sandwiching a plasticized polyvinyl butyral (hereinafter referred to as "PVB") sheet between glass plates as an interlayer film, does not scatter glass fragments even if it breaks, and can prevent objects from penetrating it.
It is widely used in windshield glass for automobiles, aircraft, etc.

In particular, laminated glass consisting of two or more interlayer films can be used as bulletproof glass.

Laminated glass generally consists of a glass plate and an interlayer film.
The stacked PVB sheets are heated to 80 to 100 degrees Celsius, and a pressure of 1 to 5 atmospheres is applied to remove the air contained between the interlayer film and the glass.
After passing through a preliminary pressure bonding process in which the interlayer film and glass are lightly bonded, they are manufactured by performing main pressure bonding at a temperature of 120°C or higher and a pressure of 10 atmospheres or higher.

Two methods are industrially adopted for the above preliminary crimping method: the nip roller method and the vacuum method. Although the latter vacuum method is more complicated,
It is widely used because of its features such as the ability to easily perform pre-pressing of curved laminated glass.

The vacuum method uses an interlayer film cut in the same way between two glass plates cut to the desired size and shape.
The laminate sandwiching the PVB sheet is placed in an airtight flexible bag generally called a rubber bag, or a ring called a rubber ring is placed between the laminate. After attaching it to the surrounding area, the pressure is reduced to remove the air contained between the interlayer film and the glass plate to prevent the generation of bubbles, and the glass and interlayer film are attached by heating to 80 to 100 degrees Celsius. Conventionally, when heating the above, a rubber bag, etc. containing the laminate was used.
Heating was done with hot air at 100-140°C, which caused a lot of heat loss and required a long time for heating and cooling. Furthermore, since the rubber bags are constantly exposed to high-temperature air, the rubber deteriorates easily, resulting in a short lifespan of the rubber bags.

In addition, the lower the temperature of the laminate until sufficient deaeration is performed, the better, preferably 25°C or less, but
It was difficult to maintain an appropriate temperature using conventional methods.

The present inventor has arrived at the present invention as a result of intensive research to solve the problems of the conventional method described above.The purpose of the present invention is to vacuum laminated glass with a PVB sheet as an interlayer film. When manufacturing using the pre-press bonding method, it prevents the generation of air bubbles between the interlayer film and the glass plate, reduces heat loss, and
An object of the present invention is to provide a method for improving heating efficiency.

The above object of the present invention is to connect a rubber bag charged with a laminate made of PVB sheets sandwiched between glass plates or a rubber ring attached to the laminate to a vacuum system, and then set the temperature to 25°C or less. After immersing the laminated body in a liquid bath and degassing it under reduced pressure, the laminate is immersed in liquid baths set at multiple different temperatures and the temperature is gradually raised to 85℃ to 100℃ to complete the pre-press bonding. This is achieved by a method characterized in that the temperature of the laminate is lowered by immersing the laminate in a liquid bath in the reverse order of the above.

A water tank is suitable as the liquid tank used for heating and cooling the laminate from the standpoint of cleaning, maintenance, etc. of the rubber bags, but other liquid heat media such as silicone oil, mineral oil, etc. may also be used.

The temperature of the first liquid bath should be below 25°C, preferably in the range of 10°C to 20°C, to prevent the unevenness formed on the surface of the PVB sheet from being crushed by pressure and interfering with degassing. It is appropriate to set

Next, 1 to 2 tanks with a liquid temperature of 35℃ to 70℃
Install the liquid tank of the tank, and finally install the last liquid tank in which the temperature of the liquid is set in the range of 80°C to 100°C, preferably 85°C to 95°C. If the intermediate liquid tank is omitted, the glass plate may be damaged due to rapid temperature rise. If there are two liquid tanks installed in the middle, the liquid temperature should be 35℃~45℃ and 60℃~
It is preferable to set it at 70℃.

For preliminary crimping, the laminate is placed in a rubber bag or fitted with a rubber ring, connected to a vacuum system, immersed in the first liquid layer, and degassed by reducing the pressure. After sufficient deaeration, the laminate is sequentially transferred to another liquid layer and heated while maintaining the reduced pressure. After immersing in the last liquid bath to complete the preliminary pressure bonding, the laminate is immersed in the liquid bath in the reverse order to lower the temperature. In this case, the laminate is taken out without being immersed in the first liquid bath whose temperature is set below 25°C.

According to the method of the present invention, the heat capacity of liquid, especially water, is large and the heat conduction with the laminate is good.
The heating and cooling time, that is, the so-called cycle time, can be shortened compared to conventional methods. In addition, since depressurization can be started at a low temperature and the laminate can be heated uniformly by stirring the liquid, there are fewer bubbles remaining in the manufactured laminated glass, improving yield and quality.

Furthermore, since the laminate moves back and forth through the heating liquid tank, heat loss can be minimized. In addition, since the operating temperature is lower than that of conventional methods, and because the rubber is immersed in liquid at high temperatures, there is almost no deterioration of the rubber, and the usable time can be dramatically extended. Therefore, the industrial utility value of the method of the present invention is extremely large.

Next, a more specific explanation will be given based on an example.

Example A piece of square clear float glass with a side length of 30 cm and a thickness of 3 mm was cut into the above shape.
Six laminates sandwiching 0.76mm thick PVB sheets,
It was placed in a square rubber bag with a side of 1 m and made of a 1.5 mm thick rubber sheet.

The first step was to set the water temperature to 15℃ using the above rubber bag.
The inside of the rubber bag was immersed in a water tank to reduce the pressure.

After 5 minutes, while maintaining the reduced pressure, it was immersed in a second water tank whose water temperature was set to 40° C. for 3 minutes. Subsequently, 65
After being immersed in a third water tank whose water temperature was set at 90°C for 3 minutes, it was immersed in a fourth water tank whose water temperature was set at 90°C for 5 minutes to complete the preliminary pressure bonding. The rubber bag was then immersed in a third water tank for 3 minutes, and then in a second water tank for 3 minutes. Thereafter, the laminate that had undergone preliminary crimping was taken out from the rubber bag.

Next, only the rubber bag was immersed in the first water tank for 1 minute to cool it, and then the next laminate was placed into the rubber bag.

The time required for one preliminary crimping was 23 minutes. Further, the above process was repeated 20 times, but it took 480 minutes. According to the conventional method, it took 440 minutes to repeat 10 times.

Furthermore, of the amount of heat required for heating, most of the amount of heat required to raise the temperature of the rubber bag containing the laminate from 40°C to 90°C can be recovered during the cooling process, reducing heat loss. Ta.

The laminated glass that had been subjected to the preliminary pressure bonding was subjected to main pressure bonding using a normal method, and the resulting laminated glass was well degassed and no air bubbles were observed.

In addition, all of the samples passed the boiling test specified in JIS R3205.

Claims (1)

[Claims] 1. When manufacturing laminated glass having a plasticized polyvinyl butyral sheet as an interlayer film using a vacuum pre-press bonding method, a rubber bag charged with a laminate formed by sandwiching the above plasticized polyvinyl butyral sheet between glass plates, or the above laminate. The rubber ring worn on the body was connected to a decompression system, and then immersed in a liquid bath set at a temperature of 25°C or less to degas it under reduced pressure.Then, the above-mentioned laminate was placed in liquid baths set at multiple different temperatures. After completion of preliminary pressure bonding by immersing and raising the temperature stepwise to 85°C to 100°C, the laminate is immersed in the plurality of liquid baths in the reverse order to lower the temperature of the laminate. A method characterized by causing