PVB lamination process and parameter recommendations

First, the cutting, cleaning and processing of glass

When cutting, the original side of the cut should be suitable to obtain a good edge stripping effect, the size should be accurate, and no difference of more than 2mm is allowed, so as to avoid the generation of bubbles due to the uneven edges. After cutting, the edge of the glass should be ground, and then cleaned with a washing machine. After cleaning, no impurities such as oil and dirt remain on the surface of the glass. The final stage of cleaning must be washed with demineralized water to avoid the change of waste due to low adhesion. After cleaning The glass is dried and placed at room temperature before use.

Second, the film

In the desired splicing chamber, after the glass is laid flat, the intermediate film is spread flat on the glass and another glass is placed. Use a knife to trim and cut the intermediate film. When trimming, the intermediate film should not be pulled to avoid the deformation of the intermediate film. The remaining amount of the outer film of the glass should be 2-5mm. When trimming, the blade should not be in contact with the glass to avoid the glass produced. The particles cause bubbles to form at the edges after processing.

Third, pre-pressure exhaust

The combined glass must be pre-pressed and vented, and the residual air between the glass and the intermediate film interface can be discharged, and good sealing can be performed before high pressure molding. Pre-pressing and exhausting are divided into two methods:

Rolling exhaust method

The combined glass is preheated, enters the roller press, is squeezed by the first roller, enters the incubator, and is pressed by the second roller, and the process is completed by exhausting and sealing. After the second roller is rolled, a full circle of transparent tape should be placed around the clip to seal the edge to prevent the gas in the autoclave from flowing back to generate bubbles. Other parts may have evenly distributed opaque parts. The single thermostat/double set of rubber roller process requires that the glass surface temperature must be strictly controlled, neither the temperature is too high, the sealing edge is too early, the internal gas cannot be discharged; Low, the edge is not complete, creating a backflow bubble. Suggestion: After the preheated glass is preheated, the surface temperature is 25~40°C. The gap of the first rubber roller should be about 1mm smaller than the total thickness of the laminated glass, and the pressure is 0.2~0.5MPa. The gap of the second rubber roller should be about 2mm smaller than the total thickness of the glass, and the pressure is 0.3-0.5MPa. When entering the second roll, the glass surface temperature must be strictly controlled at 60-80 °C. Prepare the required glass at the time of production, and carry out as continuous and uninterrupted as possible, avoiding the temperature change of the incubator due to the long interval, and the glass surface temperature cannot be accurately controlled.

2. Thermal vacuum pre-pressure exhaust method

The sealed glass is placed in a vacuum bag or surrounded by a vacuum apron, and the air in the interface of the glass/PVB intermediate film is discharged and sealed by a pressure difference by cold drawing and hot drawing. Suggestion: The vacuum degree of vacuum is above 650mmHg, the cold drawing temperature is below 25°C, the cold drawing time is above 15 minutes; the surface temperature of glass should reach 70-120°C during hot pumping, and the time is more than 30 minutes.

High pressure forming

The pre-pressed and ventilated clip glass is placed vertically on the bracket, and the adjacent clip glass spacing is greater than 5 mm. After the glass enters the kettle, the kettle door is sealed, and the temperature is raised first, so that the temperature of the kettle reaches 45 ° C, and then heated and pressurized at the same time. The heating rate was controlled at 5 ° C / min, and the pressurization speed was controlled at 0.06 MPa / min. When the temperature reaches 120-140 ° C and the pressure reaches 1.0--1.5 MPa, the holding pressure is started for 30-60 minutes. Then, when the pressure is lowered to 45 ° C, the pressure is released to atmospheric pressure, that is, the high pressure molding process is completed, and the final desired glass product is obtained. The temperature at the time of pressurization and pressure relief must be strictly controlled to avoid the generation of bubbles at the edge of the glass.