Desiccant is very common in daily life. Usually, you can buy some nut food bags, which have desiccant. The purpose of desiccant is to reduce the humidity of the product and prevent the product from being deteriorated by moisture, thus affecting the quality of the product. Taste. Although the role of the desiccant is to absorb the humidity of the air in the product, the principle of use and materials are different. There are two types according to chemistry and physics:
Chemical drying agent:
Calcium chloride desiccant
Calcium chloride is mainly made of high-quality calcium carbonate and hydrochloric acid as raw materials. It has been refined by reaction synthesis, filtration, evaporation, concentration and drying. It is often used as a calcium fortifier, chelating agent, curing agent and desiccant in the food industry. In addition, it is also used as a desiccant for gases. It can be used to dry neutral, alkaline or acid gases and is used as a dehydrating agent for the production of ethers, alcohols, propylene resins, etc. Calcium chloride is mostly porous, granular or honeycomb material, odorless, slightly bitter taste, soluble in water and colorless.
2. Quicklime desiccant
Its main component is calcium oxide, which achieves water absorption by chemical reaction, can dry neutral or alkaline gas, and is irreversible. The most common is the use of such desiccants in “snow cakes”. In addition, it is also often used in electrical appliances, leather, clothing, shoes, tea, etc., but since the quicklime is a strong alkali, it is very corrosive, and when the eyes of the elderly and children are injured, it is gradually becoming Was eliminated.
Silica gel desiccant
The main component is silica, which is granulated or beaded by natural minerals. As a desiccant, its microporous structure has a good affinity for water molecules. The most suitable moisture absorption environment for silica gel is room temperature (20~32 °C) and high humidity (60~90%), which can reduce the relative humidity of the environment to about 40%. Silica gel desiccant has the characteristics of colorless, odorless and non-toxic, stable in chemical properties and better in moisture absorption performance. Widely used in instruments, instruments, leather, luggage, food, textiles, equipment and so on. Its role is to control the relative humidity of the environment during storage and transportation to prevent moisture, mildew and rust. It is worth noting that this is the only approved desiccant in the EU.
3. Clay (montmorillonite) desiccant
Appearance shape as a gray ball, most suitable for moisture absorption in the following environment below 50 °C. If the temperature is higher than 50 ° C, the degree of “water release” of the clay is greater than the degree of “water absorption”. But the advantage of clay is that it is cheap. The desiccant is widely used in medical health care, food packaging, optical instruments, electronic products, military products and civilian products. Because it uses pure natural raw material bentonite, it has the characteristics of strong adsorption, fast adsorption, colorless, non-toxic, no environmental pollution and no contact corrosion. It is environmentally friendly, colorless and non-toxic, has no damage to human body, and has good adsorption performance. Adsorption activity, static dehumidification and odor removal.
Post time: Dec-18-2020