In the packaging field is the reduction of the dew point inside the packaging or container to eliminate humidity or guarantee preservation of qualities and properties of use of the product packed. Desiccant bag is an example of product absorbing humidity inside the packaging.

In physical chemistry absorption is the incorporation of a substance in one state into another of a different state (e.g. liquids being absorbed by a solid or gases being absorbed by a liquid).

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In the field of packaging protection we can use adsorbtion to define:

- the diffusion of VCI molecules inside the packaging

- the humidity attraction process from the raw material, like for example unpacked argile or silicagel

Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface.

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In the protective packaging sector we can speak of adsorption to define:

- the phenomenon of diffusion of VCI molecules in the packaging

- the process of moisture attraction by raw materials, such as clay or unpackaged silica gel

In the chemical-physical field, adsorption is generally a particular type of absorption that occurs only at the surface.

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Bentonite is a clayey mineral made of montmorillonite, calcium or sodium. In the packaging field bentonite is used as desiccant in bags of non-woven tissue to eliminate humidity inside packagings.

Propasecard desiccant indicators are free from Cobalt chloride.

Cobalt chloride is the cobalt salt of hydrochloric acid.

At room temperature it appears as a pink odorless solid. When heated, it undergoes partial dehydration taking on a blue-violet color. It is a carcinogenic, harmful, allergenic compound that is dangerous for the environment.

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The formation of condensate, or condensation (also called liquefaction), is the phase transition from the gaseous phase to the liquid phase of a substance. This transformation can be performed at constant temperature, by compression if the gas temperature is below the critical temperature, or by cooling with an external source or by adiabatic expansion; in any case, the condensation operation is exothermic.

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Propagroup product range for humidity protection also includes a specified desiccant to be used inside container, PROPADRY.

An intermodal container or freight container is a reusable transport and storage unit for moving products and raw materials between locations or countries; the terms container or box may be used on their own within the context of shipping.

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A desiccant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately well-sealed container. Commonly encountered pre-packaged desiccants are solids, and work through absorption or adsorption of water, or a combination of the two. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. Pre-packaged desiccant is most commonly used to remove excessive humidity that would normally degrade or even destroy products sensitive to moisture. Drierite, Silica gel, calcium sulfate, calcium chloride, montmorillonite clay, and molecular sieves are commonly used as desiccants.

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Desiccant clay is the commonly used name for calcium bentonite (montmorillonite), a naturally occurring material that is chemically inert, non-corrosive and composed mainly of calcium and magnesium alumino silicates.

Desiccant clay is the commonly used name to define calcium bentonite (montmorillonite), a naturally occurring material that is chemically inert, non-corrosive and composed mainly of calcium and magnesium aluminum silicates.

Humidity is the measure of the amount of water vapor present in the atmosphere (or generally in an air mass).
Relative humidity, in particular, indicates the percentage ratio between the amount of vapor contained by an air mass and the maximum amount (i.e., at saturation) that the air volume can contain under the same temperature and pressure conditions. At the dew point temperature, relative humidity is by definition 100%. Relative humidity is a parameter given by the ratio between absolute humidity and saturation humidity. It is independent of temperature and gives an idea of the saturation rate of atmospheric vapor, and the repercussions on evapotranspiration phenomena of crops. The saturation deficit is given by the difference between absolute humidity and saturation humidity.

Molecular sieves are materials that can separate molecules based on size. This capability is based on the presence in the material of tiny pores of exact and uniform size, with a diameter between 3 and 10 Å depending on the material. Molecular sieves have a very high surface area within the pores (600-700 m2/g). Molecules larger than the pores cannot enter the material. Molecules small enough to penetrate through the pores can enter the material; generally polar molecules are adsorbed on the internal surface of the pores and remain trapped, while apolar molecules are not retained. The most commonly used materials as molecular sieves are aluminosilicates and in particular zeolites, both natural and synthetic. Other materials such as aluminophosphates or polymeric cyanocomplexes have a porous structure in principle suitable as molecular sieves, but so far have not been used in technical applications.

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Silica gel is most commonly encountered in everyday life as beads packed in a vapor-permeable plastic. In this form, it is used as a desiccant to control local humidity in order to avoid spoilage or degradation of some goods. Because of poisonous dopants (see below) and their very high absorption of moisture, sílica gel packets usually bear warnings for the user not to eat the contents. If consumed, the pure silica gel is unlikely to cause acute or chronic illness, but would be problematic nonetheless. Food-grade desiccant should not include any poisons which would cause long-term harm to humans if consumed in the quantities normally included with the items of food.

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In many items, moisture encourages the growth of mold and spoilage. Condensation may also damage other items like electronics and may speed the decomposition of chemicals, such as those in vitamin pills. Through the inclusion of silica gel packets, these items can be preserved longer.

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