Laminated glass is a widely used glass in the field of architectural glass, which is also known as safety glass. Laminated glass, as the name suggests, is composed of multiple layers of glass, in addition to the glass, the remaining is the sandwich in the middle of the glass, usually there are three kinds of sandwich: EVA, PVB, SGP.

SGP intermediate membrane:

SGP stands for ionic intermediate membrane (Sentryglass Plus), which is a high-performance sandwich material developed by DuPont Company. Its high performance is reflected in:

1, excellent mechanical properties, high strength. Under the same thickness, the bearing capacity of SGP sandwich is twice that of PVB. Under the same load and thickness, the bending deflection of SGP laminated glass is one quarter of that of PVB.

2. Tear strength. At the same thickness, the tearing strength of PVB adhesive film is 5 times that of PVB, and it can also be glued to the glass in the case of tearing, and will not make the whole glass drop.

3, strong stability, moisture resistance. SGP film is colorless and transparent, UV resistant, after long-term sun and rain, it is not easy to turn yellow, yellowing coefficient < 1.5, while the yellowing coefficient of PVB sandwich film is 6~12. Therefore, SGP is the favorite of ultra-white laminated glass. Although the production process of SGP is close to that of PVB, the terminal price is high, so it is not widely used in China and its awareness is low.

EVA sandwich film:

EVA stands for ethylene-vinyl acetate copolymer. Because of its strong water resistance and corrosion resistance, it is widely used in packaging film, functional shed film, foam shoe material, hot melt adhesive, wire and cable and toys and other fields, China usually uses EVA as sole material.

EVA is also used as the sandwich of laminated glass, its high cost performance, compared with PVB, SGP, EVA fluidity is better, the melting temperature is low, the temperature can be processed when it reaches about 110℃. Its full set of production equipment needs about 100,000 yuan.

The membrane of EVA has good fluidity, and can be used in the membrane for wire clamping, clamping and other processes to make beautiful decorative glass with patterns and patterns. EVA has good water resistance, but the ability to resist ultraviolet light is weak, long-term sun is easy to yellow and black, so it is mainly used for indoor partition.

PVB sandwich film

PVB layer is believed to be one of the more familiar names. PVB is also a widely used sandwich material for architectural glass and automotive glass. The storage process and processing method of PVB interlayer are more complicated than EVA, and the requirements for temperature and humidity are higher. PVB processing requires the temperature to be controlled between 18℃-23℃, the relative humidity to be controlled at 18-23%, PVB to maintain 0.4%-0.6% moisture content, through the process of preheating rolling or vacuuming is the use of autoclaved heat preservation pressure

Autoclave temperature: 120-130℃, pressure: 1.0-1.3MPa, time: 30-60min. PVB complete production equipment needs about 1 million funds, which is difficult for small businesses. In a few years ago, mainly to foreign Dupont, Shou Nuo, water and other manufacturers, domestic PVB is mainly recycled materials for secondary processing, but the quality stability is not very good. In recent years, domestic PVB manufacturers are also gradually developing. PVB has good safety, sound insulation, transparency and UV resistance, but PVB water resistance is not good, long-term in a humid environment is easy to open and fall off.