Laminated glass products are made of float glass, toughened glass, heat reinforced glass, colored glaze glass, heat reflection glass, LOW-E glass and so on. Before processing, glass should be selected according to the internal control standard of laminated glass south glass, requiring no wave tendons, stones, scratches, edge collapse, and the smoothness of tempered glass should be checked. Because of the uneven glass and the existence of wave reinforcement, in the process of pressing will make the glass and film can not be bonded, and easy to form bubbles in the wave reinforcement and uneven.
The main component of laminated glass PVB film is polyvinyl butyral, which is the condensation product of polyvinyl alcohol and butyral. The plasticizer used in PVB film can improve the softness of the film and increase the elongation of the film without affecting the tensile strength, thus improving the impact resistance and penetration resistance of laminated glass at low temperature. The bonding principle of laminated glass is that the OH of PVB film combines with the O in the glass and has the bonding force.
The bonding effect is generated by the exchange and mechanical connection between the water molecules on the glass surface and the electrons of the water molecules in the film. The purity of the washing water has a certain effect on the bonding property, and impurities in the water will reduce the bonding property. The mechanical strength of laminated glass largely depends on the moisture content of PVB film, but it is not the lower the moisture content of the film, the better. Moisture control of film is very important in laminated glass production. When the moisture content is too little, the film is very brittle, the strength of the laminated glass decreases significantly, so that when the glass is impacted can be broken down. When the moisture content is high, the adhesive force between the film and the glass is reduced and leads to degumming and foaming in use. Generally, the moisture content of the film for building glass is between 0.3% and 0.6%. In this range the film bonds tightly to the glass.