Desiccant Types

Author: Wisepac  

Raw material of absorbent

The absorbent is a type of material capable of absorbing water vapor. It can absorb the water vapor in the external environment through the physical or chemical methods and lock it, so as to realize the dry and moisture resistance purposes. At present, the widely used absorbents for dry and moisture resistance mainly comprise: montmorillonite, active mine, silica gel, molecular sieve, calcium chloride.


1. Brief introduction: Montmorillonite is also named as microcrystalline kaolinite, which is the desired mineral of bentonite mine. Due to different causes of formation, metallogenic environment, origins, montmorillonites in the world appear different colors such as white, light gray, pink, light green, etc. and the forms are irregular, which can be processed into spherical state. Due to its crystal structure and molecular composition, it is free of toxicity and harm and can be naturally degraded. In addition, it has strong adsorbability and cation exchange performance, enabling it to be widely used in the absorbent 

2. Characteristics:
a. It is manufactured through the drying, breaking and sieving of natural bentonite and can be naturally degraded. It is a natural environmental friendly product and free of toxicity and harm.
b. When the relative humidity is below 20%, the moisture absorption is superior to silica gel and the cost is lower.

3. Performance index:

Item name Index Typical data of Wisepac

Water content(180℃)



Specific resistance(s/m)



PH value



Stacking density(g/l)



Qualified rate of particle size



Water soluble matter




20% RH



40% RH



4. Table of hydroscopicity of montmorillonite (25℃ RH10%-90%):

 Silica gel

1. Brief introduction: the main component of silica gel is an amorphous silica, transparent or milky irregular particle or spherical solid.It features open-type porous structure and can absorb many substances due to its strong adsorbability. It is a high-performance active adsorbent.
2. Characteristics:
a. Free of toxicity and odor, stable chemical property. Can not react with any other substances except strong alkali and hydrofluoric acid.It is adsorption material for desiccant accepted by FDA can directly contact with drug and food. It is safety and reliable.
b. The silica gel has strong adsorption capacity under various conditions.
3. Performance indexes:

Item name Index Typical data of Wisepac

Water content



PH value



Specific resistance(Ω.㎝)



Stacking density(g/L)



Qualified rate of particle size



4.Chart of Absorption Capacity(25℃ RH10%-90%):

Indication silica gel: 
1. Brief introduction: the indication silica gel mainly comprises blue silica gel and orange silica gel, wherein the orange silica gel comprises changing orange to green and changing orange to white. The color-variable silica gel has the same performance of white silica gel. After moisture absorption, the color variation is useful to observe the wet state.
2.Performance Indices:

Item Criteria Wisepac Typical Value

Moisture Content



Bulk Density(g/L)



Qualified Granules



Unit Absorption Capacity








 The adsorbent of container

1. Brief introduction and characteristics: the adsorbent of container adopts the unique formulation, whose main component is calcium chloride. Under 25°C and 90% humidity, the moisture absorption capacity can reach 280%, and the adsorbent will become gel after complete moisture absorption without reverse osmosis. Combined with this adsorbent and Wisepac compound membrane nonwoven cloth, the package can not be broken due to its strong strength.

2.Chart of Absorption Capacity(25℃ RH10%-90%):


 Active mineral

1. Brief introduction: the active mineral desiccant is formed through the activation treatment of attapulgite and has better moisture adsorption ability than montmorillonite. Due to the chloride ion content, it can not directly contact with food, drug, metal, etc.
2. Characteristics: The moisture adsorption capacity under high humidity is good. 
3. 活矿性能指标:

Item Criteria Wisepac Typical Value

Moisture Content(180±5℃)、%



Unit Absorption Capacity




PH Value



Bulk Densityg/L



Qualified Granules



4. Chart of Absorption Capacity(25℃ RH10%-90%):

 Molecular sieve

1. Brief introduction: it is a crystalline aluminosilicate compound which contains neat and uniform pore channel in the crystal structure. The hole diameter is molecular level, which only allow the molecule smaller than this hole diameter to enter; therefore, the molecules in mixture shall be sieved as per diameter, which is consequently named as molecular sieve. 
2. Characteristics:
a. When the humidity is extremely low, the water vapor in environment can still be absorbed greatly and the environmental humidity can be effectively controlled.
b. The moisture adsorption speed is extremely fast, large quantity of water vapor can be absorbed within extremely short time.
3.Performance Indices :

Item Criteria Wisepac Typical Value

Moisture Content(550±5℃)



Unit Absorption Capacity




19.3(4A) 21.6(13X)




21.5(4A) 23.8(13X)

4.Chart of Absorption Capacity(25℃ RH10%-90%):