As a building energy-saving material, insulating glass is widely used because of its good thermal and acoustic insulation properties. The biggest quality problem of insulating glass is that the air layer condenses in use, and the reason for the air layer condensation is that the dew point of the air layer rises in the process of use. Therefore, controlling the dew point of insulating glass is the key to controlling the quality of insulating glass.
During the use of insulating glass, when the ambient temperature drops to the point where the surface temperature of the glass drops to the dew point in the dry air layer, condensation or frost will form on the surface of the dry air layer. The performance of insulating glass is affected by condensation or frost on the inner surface of the glass. If it is ensured that the air layer does not condense at minus 40℃, the insulating glass will not condense in the air layer during use.
Analysis of the reasons for the rise of the Dew point
The dew point of insulating glass refers to the temperature when the air humidity in the air layer reaches saturation. Below this temperature, water vapor in the air layer condenses into liquid water. It can be deduced that 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 moisture in the air will condense or frost on the inner surface of the glass.
The dew point rise of the insulating glass is caused by the external moisture entering the air layer without being absorbed by the desiccant.
Three reasons may cause the dew point rise:
1) The sealant memory has bubbles, resulting in air moisture.
2) Water and gas can diffuse into the air layer through the polymer.
3) The effective adsorption capacity of the desiccant is low.
Insulating glass dew point control measures
1) Strictly control the temperature of the production environment
The production environment mainly affects the adsorption capacity and residual adsorption capacity.
2) Reduce the diffusion of water through the polymer
It mainly depends on choosing a sealant with a low permeability coefficient, determining a reasonable sealing thickness, and reducing the temperature difference between the inside and outside of the insulating glass (that is, controlling the production within a certain temperature range and not making the temperature range too large).
3) Reduce production process time
Minimize the time that the desiccant is in contact with the atmosphere and reduce the loss of adsorption capacity so that the desiccant has a higher adsorption capacity.
4) Choose the right aluminum profile
The air-guiding slit of the pores should be small to reduce the water absorption rate of the molecular sieve during the operation.
5) Choose the right desiccant
Choose a desiccant with a high adsorption rate and long-lasting.