1、Cutting, cleaning and processing
The cutting trace along the original side should be proper in order to get a well peeling effect. The size should be precise. Errors should be no more than 2mm lest the ragged side brings bubbles. After cutting the glass side should be rubbed and then cleaned by washing piece. after cleaning there should not be greasy leftover on the glass. the endgame of cleaning needs softening water to rinse in case it should become wasted for lacking cohesive force. the clean glass can only be used after it is terrified and cooled to normal temperature.
In a qualified glass-lamination room(temperature:20-25C,Humidity:25%), the laminating room should be clean, workers wear static-free clothes. The PVB film should be kept 24 hours in laminating room before lamination, when lamination, spread out the film on a layer of the glass, leave about 2-3mm edges outside the glass layers. overlapping, stretching, and touching directly the PVB film is prohibited.
Put the warmed-up laminated glass into a calendar press; after the first rolling, put it into a thermo slated container; after the second rolling, seal a transparent band around the laminated glass which well seals the edge in case the all in high pressure autoclave should stream back and cause bubbles. Nontransparent areas distributed evenly in the other parts are allowable. This technique of using single thermo-stated container and double rubber roller squeezer requires strictly-controlled temperature on the surface of the glass it can neither be too high. In this case it makes the edge sealing too early to allow the interior air exhaust successfully, nor too low, in this case it makes the edge sealing imperfect which causes back-steaming bubbles. Suggestion: keep the surface temperature of the laminated glass at 20-40C,the mill clearance of the first rubber-rollers should be about 1.50mm less than the laminated glass thickness and the pressure is 0.20-0.50Mpa. the second roller squeezing process should be about 2mm less than the laminated glass thickness, and the pressure is 0.40-0.70Mpa. In the second roller squeezing the surface temperature of the laminated glass must be strictly controlled within 50-70C. when manufacturing, prepare all the glass in advance and try the best to do the process continuously and avoid long waiting time intervals, in case the temperature in the thermo-stated container changes too violently so that the surface temperature cannot be controlled precisely. It lead to bubbles during pre-pressing process.
4、Vacuum Pre-press Process
Put the laminated glass into a vacuum bed or vacuum rubber gasket. With cool pumping 2-15 minutes, heating up to 95-105C and keeping 20-45 minutes, the vacuum bag or vacuum rubber gasket must not be taken out until cooling the temperature down to 60C,decompression vacuum degree is beyond 650mmHg during the whole pre-pressing exhaust process.
5、High-pressure finished product process
Put the laminated glass which have been exhausted upright on the bracket, leaving the distance between the bordering glasses be more than 5mm. Seal the door after glasses are put in the thermo container, first raise the temperature to 45C then raise the temperature and pressure at the same time. During the first stage, keep the temperature at 90C,pressure0.60Mpa,when the temperature reaches 125-135C and pressure reaches 1.10-1.25Mpa,then keep them the same for 30-60minutes;after that, Keep the pressure and lower the temperature to 45C,then lower pressure to atmospheric pressure, this finishes the high pressure process and finally get the product of laminated glass. the temperature must be controlled strictly when raising and lowering pressure in case of generating air bubbles in the edge of the glass interlayer.