What is a silica gel desiccant?
The main component of the silica gel desiccant is silica, an amorphous machine made of sodium silicate and sulfuric acid in silica. It is washed or processed by minerals found in nature to become granular or beaded.
Its structure is very similar to a sponge. It consists of interconnected pores that form a capillary adsorption system with a large surface area that absorbs and retains moisture. At a humidity of 100%, it can adsorb and condense moisture equivalent to 40% of its own weight.
The average pore size of the silica gel desiccant is 24 angstroms (Angstrom; is a unit of length, 1 angstrom = 10 minus ten square meters, is a unit of length smaller than nanometers, 1 angstrom = 0.1 nanometer length unit) It can absorb moisture even when the temperature is higher than 105 °C, but when the temperature is higher than 38 °C, its moisture absorption rate begins to decrease, its optimal moisture absorption state is 21 ° C -32 ° C, even if the relative humidity is 60% higher - At 90%, the relative humidity in the container can also be maintained at 40%.
Because silica gel desiccant is chemically safe, highly safe, non-toxic and non-corrosive, it is approved by the US FDA for use in the food and pharmaceutical industries. Silicone desiccant has a wide selection of packaging materials, generally OPP/PE, PET/PE film, non-woven fabric, composite paper and so on.
What is the indicator silica gel desiccant?
The silica gel desiccant is a combination of silica gel particles or granules and cobalt chloride (a heavy metal salt). Cobalt chloride has a dark blue color. When it is from a dry state to a hygroscopic saturation state, its color changes from dark blue to purple. Usually when the moisture absorption exceeds 8% of its own weight, its color will change completely, which means that the desiccant needs to be replaced.
The silica gel desiccant is usually used for products that are sensitive to moisture. This makes it easy to check and adjust. It can visually indicate the performance of our products. However, because it contains cobalt chloride, it cannot be used in the food and pharmaceutical industry. Generally, 10% of the indicator silica gel can be mixed in the desiccant for two reasons. One is that 10% of the indicator silica gel desiccant is sufficient to show the change of color; the other is that the price of the silica gel desiccant is higher.