Air separation glass molecular sieve:

1. The role of molecular sieve in insulating glass

We all know that even if the doors and windows in the past were double-decker, then in winter (north)

Frost will appear. It is produced due to the saturation of water content in the air into water when the temperature change decreases. The water molecules thus resolved attach to the inside of the window to form frost. Then, after the hollow glass is put into the molecular sieve, after being sealed with glue, the molecular sieve will adsorb the water molecules in the glass interlayer (up to several ppm). In this way, no frost will form. At the same time, due to the reduction of mesons, it can also play a better role in thermal insulation.

2、 about the choice of molecular sieve

According to the description in the first part, we know that the insulating glass is composed of

Part glue (butyl, polysulfide) seal. No matter what kind of glue air has a certain permeability, so we must choose a molecular sieve with a high adsorption value. In other words, even if air penetrates, the molecular sieve can absorb more water molecules. Make it reach a certain dew point. When the molecular sieve adsorption reaches a certain value, when the dew point decreases with the entry of air, the hollow glass will dew. This period of time is called the service life of insulating glass, so when choosing a molecular sieve, you must choose a product with a high adsorption value. The molecular sieve adsorption value and falling powder are contradictory, and the large powder will also affect the transparency of insulating glass.

3. Testing of molecular sieves

Adsorption heat (heating) Take 25ml water to measure the temperature. Take 25g molecular sieve into water to measure temperature

degree. The temperature difference between the two is the temperature rise, the standard is 30 degrees. Generally, an increase in temperature indicates that the adsorption value is high.

1. Powder falling degree: Take 5g molecular sieve into 100ml water, shake it evenly, and put it into the turbidity meter for detection. Read the number as turbidity. The requirement is less than 50ppm. If there is no turbidity meter, the molecular sieve can be brought to a certain height to be exposed to the sun, and no dust is better.

Therefore, when choosing a molecular sieve, it is better to look at the smaller powder. Then the good molecular sieve mentioned above is the large adsorption value and small powder fall.

In addition, hollow glass molecular sieve has 3A and 4A (because 4A is low in price), the pore size of 3A molecular sieve is about 3.2-3.3A. (1A = 810 cm). The 4A aperture is 4.2-4.7A. Among them: the diameter of water molecule is 2.8A. So it can play a role in adsorbing water molecules 3A and 4A. The molecular diameter of nitrogen in the air is 3.6A, so that 3A will not adsorb nitrogen; and 4A can adsorb nitrogen. Then, due to the characteristics of molecular sieve, it is adsorbed in cold and regenerated in heat. Therefore, when using 4A molecular sieve, the molecular sieve will continue to adsorb nitrogen in the interlayer when the temperature is lower than the temperature of the lamination after lamination. This will cause the negative pressure hollow glass to appear concave; when the temperature is higher than the lamination temperature, the nitrogen adsorbed in the 4A molecular sieve cavity will be released, and the hollow glass will appear convex, so that people will not visually Well, and the temperature changes 24 hours a day, so that means the insulating glass also changes. This will accelerate the fatigue of the fixing glue (polysulfide) and sealant (butyl) and shorten its service life.

In addition, in order to prolong the service life, in addition to choosing a good molecular sieve, we must also choose a good hollow glue.