Insulating glass, as a building energy saving material, is widely used because of its good thermal and sound insulation properties. At the same time, the quality requirements of insulating glass are getting higher and higher. It is understood that the biggest quality problem of insulating glass is the condensation of the air layer in use, and the reason for the condensation of the air layer is that the dew point of the air layer rises during 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 is reduced to reduce the surface temperature of the glass to the dew point in the dry air layer, the surface of the dry air layer will produce dew or frost. The condensation or frost on the inner surface of the glass will affect the performance of the insulating glass. If the air layer does not condensation above minus 40 ° C, the hollow glass will not appear in the process of air condensation.

1. Analysis of the causes of dew point rise

The dew point of insulating glass refers to the temperature when the humidity of the air sealed in the air layer reaches saturation. Below this temperature, water vapor in the air layer condenses into liquid water. The higher the content of water that can be extruded, the higher the dew point temperature of the air, when the inner surface temperature of the glass is lower than the dew point of the air in the air layer, the moisture in the air will dew or frost on the inner surface of the glass.

The dew point rise of insulating glass is caused by the outside water entering the air layer and not being absorbed by the desiccant. There are three reasons that may cause the dew point to rise:

(1) There are bubbles in the sealant memory, causing air moisture to enter.

(2) Water vapor diffuses into the air layer through the polymer.

(3) The effective adsorption capacity of desiccant is low.

Second, insulating glass dew point control measures

(1) Strictly control the humidity of the production environment

The production environment mainly affects the adsorption capacity and residual adsorption capacity of desiccant.

(2) Reduce the diffusion of water through the polymer

Mainly by selecting a sealant with low permeability coefficient and determining a reasonable sealing thickness, the internal and external temperature difference of the insulating glass is reduced (that is, the production is controlled within a certain temperature range without making the temperature range too large).

(3) Reduce the production process time

Minimize the time of contact between the desiccant and the atmosphere, reduce the loss of adsorption capacity and make the desiccant have a higher adsorption capacity.

(4) Select the appropriate aluminum profile

The air conduction gap of the fine pores should be small to reduce the water absorption of the molecular sieve during operation.

(5) Select the appropriate desiccant

Choose desiccant with high adsorption rate and long lasting.

It is believed that the quality of insulating glass will be obviously controlled through the control of various links such as material selection, processing, and environment.