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Molecular sieve is a synthetic hydrated silicate aluminate (zeolite) or natural zeolite with the function of screening moleculars. Its pore size is similar to general molecular size, which can be controlled by different processing technology. Only molecules with diameters smaller than the aperture are allowed in. Besides adsorbing water gas, it can also adsorb other gases.
According to the ratio of silicon to aluminum and crystal structure, molecular sieve can be divided into A type, X type, Y type, etc. According to the pore size of molecular sieve, molecular sieve can be divided into 3A molecular sieve, 4A molecular sieve and 5A molecular sieve. Among them, 3A molecular sieve will be used more in the hollow glass.
The effective pore size of 3A molecular sieve is about 3A. The effective pore size of 4A molecular sieve is about 4A. The radius of water molecule is less than the aperture of 3A molecular sieve, which can be adsorbed by 3A molecular sieve. However, the molecular radius of oxygen and nitrogen is larger than the aperture of 3A molecular sieve, and can not be adsorbed by 3A molecular sieve. However, 4A molecular sieve can adsorb water, oxygen, nitrogen, and even more inclined to adsorb larger polarity of nitrogen.
It should be noted that nitrogen adsorbed by 4A molecular sieve is very sensitive to temperature changes. For example, 250ml 4A molecular sieve can release more than 700ml gas from room temperature to 70℃. And the 3A molecular sieve will be less than 50ml.
As a desiccant for insulating glass, when the external temperature rises, 4A molecular sieve will release adsorbed nitrogen and oxygen, resulting in internal pressure of insulating glass greater than external pressure. Then insulating glass will convex. When the external temperature is reduced, 4A molecular sieve will absorb nitrogen and oxygen again, so that the external pressure is greater than the internal pressure of hollow glass. Hollow glass will concave or recover. This "breathing phenomenon" of inhaling and releasing air will greatly reduce the service life of insulating glass. Experience shows that the service life of insulating glass using 4A molecular sieve is only a quarter of that of 3A molecular sieve.
Select high-quality molecular sieve raw materials. At low humidity, it has advantages of great hygroscopic ability and strong thermal stability and others. Although there are many kinds of molecular sieve, theory and practice have proved that only 3A molecular sieve desiccant which does not adsorb air is suitable for insulating glass!
The raw materials and products of Naike molecular sieve desiccant have been very mature, and the products have been tested and recognized by our customers. In the future, we will continue to improve our research and development and innovation ability, and bring better products. If you have any need, please feel free to consult us online.