2 Best insulating glass sealant selection
Insulating glass sealant selection. During the use of insulating glass, it is always facing the influence of external water vapor penetration, wind and rain, ultraviolet radiation, temperature difference, and air pressure, wind load and other external forces. The combined effect of various environmental factors makes the insulating glass face a relatively harsh environment. Therefore, the sealant must have the properties of watertightness, airtightness, radiation resistance, temperature difference resistance, and moisture resistance. Choosing high-quality sealant is one of the prerequisites for improving the service life of insulating glass.
Selection of insulating glass sealant
At present, the sealing and laminating process in the production of insulating glass adopts double-pass sealing technology.
The first seal uses hot-melt butyl sealant (butyl sealant for short). Butyl sealant has extremely low water vapor permeability, which can effectively prevent external water vapor from entering the hollow glass cavity, and at the same time prevent inert gas from escaping from the cavity, so that the insulating glass maintains a long-term energy-saving effect. Therefore, one seal plays a decisive role in the airtightness of insulating glass.
Butyl sealant itself cannot be completely cured, its cohesive strength and bonding strength are relatively low, its elasticity is very small, and its ability to prevent glass dislocation is very weak. Therefore, butyl glue cannot complete the assembly of insulating glass independently, and the insulating glass must be sealed twice to assemble a structurally stable insulating glass unit.
The second seal usually uses silicone sealant, and a few also use polysulfide sealant or polyurethane sealant. The second insulating glass sealant must have excellent strength, elasticity and adhesion to the glass. At the same time, the second sealant should also have good resistance to natural aging such as high and low temperature changes, high humidity and ultraviolet radiation.
After the insulating glass is bonded and sealed with the second insulating glass sealant, a structurally stable insulating glass unit is formed. The second sealant can protect the first sealed butyl glue from dislocation, debonding and other damage phenomena, and assist the butyl glue in airtightness.
Compared with the first sealed butyl glue, the water vapor permeability of the second sealant such as silicone sealant is relatively high. If there is no first sealed butyl glue, the insulating glass is not airtight if it relies solely on the second seal. Therefore, the double-pass sealing of insulating glass is indispensable. Without any one of the seals, the quality and function of the insulating glass cannot be discussed.
