Insulating glass has been widely used in buildings as an energy-saving transparent structural part of building exterior walls, and has many applications in other industries such as trains, airplanes, refrigeration equipment, greenhouses and other industries. Due to insufficient attention to the sealing of insulating glass in the production process, it is very easy to cause the sealing failure of the insulating glass and lose the energy-saving performance of the insulating glass.

The direct reason that affects the effective use time of insulating glass is the speed at which moisture converges in the middle layer. There are many factors that affect the speed of moisture gathering in the middle layer, such as material properties, manufacturing processes and control, installation methods, and environmental aging. The dew point of hollow glass refers to the temperature when the humidity of the air sealed in the air layer reaches a saturated state. When the temperature is lower than this temperature, the water vapor in the air layer will condense into liquid or solid water.

The higher the water content, the higher the dew point temperature of the air. When the temperature of the inner surface of the glass is lower than the dew point of the air in the air layer, the water vapor in the air in the hollow cavity will accumulate in the hollow cavity of the hollow glass, causing the dew point to rise. When the ambient temperature drops and the temperature of the inner surface of the glass is lower than the dew point of the air layer, the moisture in the air layer will cause condensation or frost on the inner surface of the glass (condensation when the temperature of the inner surface of the glass is higher than 0°C, lower than 0 ℃ frost). Due to condensation or frost on the inner surface of the glass, it will seriously affect the perspective of the insulating glass and reduce the insulating effect of the insulating glass. At the same time, long-term condensation will cause mildew on the inner surface of the glass or white spots due to alkali , Which seriously affects the use of insulating glass. The national standard GBT 11944-2012 "Insulating Glass" stipulates that the dew point temperature of hollow glass is <-40℃. The increase in the dew point of hollow glass is mainly caused by the fact that external moisture enters the air layer and cannot be absorbed by the desiccant.

To increase the service life of insulating glass and extend the effective use time to meet the standard requirements, it should be controlled from material selection, processing and manufacturing, structural design and installation.