Desiccant Pouches (Technical Information)

Desiccant Pouches (Technical Information)

Desiccant is a substance that is very hygroscopic (adsorbs moisture from the air) in nature. There are different kinds of such desiccants available, however, only a few would serve your purpose.

We have our “Eco-desiccant” (Silica Gel, Clay Desiccant, Heavy Duty Desiccant) which is one of the most efficient desiccants available in the market.

Multitech Desiccant Pouches are an ideal solution for helping to protect your valuable products from moisture damage. These desiccant pouches are designed to absorb moisture from the air and keep your products safe and dry. They are easy to use and come in a variety of sizes and shapes to suit a variety of applications.

Why Desiccants?

The shipping products around the world come across different temperatures & humidity conditions. These variations cause damage to cargo due to moisture. Please note, every year thousands of containerized cargos are damaged by moisture problems. Metal parts arrive corroded, cardboard boxes mould & wet, food commodities are found to be unfit for consumption.

The root cause of moisture damage in container transport is the simple fact that warm air can hold more moisture than cold air i.e. when temperature decreases the moisture in air gets condensed to water molecules. It’s like a dew grass in the morning after a cool summer night as an example. Thus when the temperature in the container changes, damaging moisture conditions arises. The only remedy is to keep the air inside the container & inside packages dry. These desiccants controls the moisture level in the containers, crates, boxes & so on.

Moisture damage happens even where there is no condensation. Many grades of steel will start to corrode at a relative humidity of about 70%. Mould growth could begin after even a short period of over 80%. The fungus growth on wood material is due to this moisture in the container.

The only remedy is to keep the air inside the container dry. The first thing to do is to ensure that the cargo and all the packaging are as dry as possible. A wet container floor or some pallets stored in the rain may be enough to ruin a cargo.

No container is airtight whatever you do, it will “breathe” as a result of temperature cycles. When the air inside the container cools, the pressure drops. Air and moisture moves in from the outside to equalize the pressure. The opposite happen when the air inside the container heats up, but it is easy to show how a repeating cycle of breathing can cause a build up of moisture inside the container, especially if there is absorbing packing materials. Using a container with good seals and vents taped shut will slow down, but not stop- the “container breathing”.

Packaging and wrapping the goods in plastic foil will not necessarily help. Moisture migrates quite quickly through most types of plastic foil. Even if a moisture proof foil is used, there could still be a problem since the sealed package then in effect becomes a “mini-container” subject to the same processes as the container.

What causes condensation in your container?

  • Significant temperature variations – i.e. crossing the equator and day-night temperature fluctuations.
  • When container temperature rises, air expands and absorbs free moisture molecules from all possible sources i.e. container floor, wooden pallets & wooden packaging material, from outside of container as no container is air tight.
  • When the container temperature drops, the air contracts and deposits the heavier water molecules, known as condensation.
  • This process of warming and cooling can repeat itself several times during a voyage which causes this damaging condensation cycle.
  • The only remedy for such problem is to use container desiccants.
  • If above product is not used, the damage to your product can be to the extent as shown in above photographs.

Important Technical information

The following sources must be taken into consideration with regard to sweat formation in the container :

  • the water vapor content of the air in the container.
  • the water vapor content of the air supplied by ventilation.
  • the water content of the cargo.
  • the water content of packaging, accompanying material and dunnage.
  • rainfall during loading.
  • penetration from outside where containers are damaged.

Temperature & water vapor content of the air Mollier h/x diagram.

Some fundamental product information issues need to be brought to mind for the following explanations.

Air always contains a certain proportion of water vapor, approx. 3 g/m³ in cold, dry air, as much as 30 g/m³ in warm, humid air. This is only a small proportion, amounting to at most 3% of the mass of the air, but has a considerable meteorological impact, as is clear from the day to day changes in the weather.

Decisively, the atmosphere can only contain a certain quantity of water vapor, the saturation content, which is dependent upon temperature. The hotter is the air, the more water vapor it may contain.

Once the saturation content is reached, no further water can evaporate. Relative humidity is now 100%. A relative humidity of 60% means that air contains 60% of the saturation content.

The lower the relative humidity, the more intensively does water vapor adsorption proceed, so bringing about a drying action.

One clear parameter which indicates the risk of sweat formation is the dew point temperature of the air. This is the temperature at which the water vapor contained in the air reaches its saturation content and, if cooling continues, condensation occurs.

If the dew point temperature is known, it is possible to estimate the risk of sweat. The interrelationships between these variables are presented in diagrams. Fig. 1 shows a Mollier h/x diagram which is very well suited to such conversions.

The temperature values, i.e. air and dew point temperature, can be read from the Y-axis, while the mixture ratio x (g/kg) can be read from the X-axis. The mixture ratio x states how much water vapor one kilogram of dry air contains.

The curves running from the bottom left to the top right indicate the relative humidity in 10% increments. The bottom curve applies to a humidity of 100% and is thus known as the saturation curve. The position of a given mass of air within these coordinates must always be defined by at least two values, one of which should always be the air temperature. The second coordinate is then determined by the mixture ratio x, relative humidity or by the dew point.

The following three examples show how, starting from the known values, the others are determined. All the points from which the results are read off are indicated with an arrow in the Figure.




Example 1:

The air temperature t = 15°C and

relative humidity f = 70% are known;

Root : the mixture ratio x and dew point.

Result : x = 7.3 g/kg = 9.5°C

Example 2:

The air temperature t = 20°C and

mixture ratio x = 10 g/kg are known;

Root : relative humidity f and dew point.

Result : f = 69% = 14.1°C


Example 3:

The air temperature t = 18°C and

dew point = 4°C are known;

Root : relative humidity f and mixture ratio x.

Result : f = 39% x = 5.0 g/kg

Product Details

We are the manufacturers of “Eco-desiccants” having manufacturing facilities in Pune. “Eco-desiccant” is environmental friendly moisture adsorbing material having vigorousadsorption capacity over large temperature range i.e. it removes moisture from air very aggressively.

  • It contains highly activated clay which is chemically inert & non-corrosive.
  • It adsorbs moisture without changing the physical shape of the particles.
  • It contains montmorillonite clay along with mixture of other additives so as to make ithighly absorbing material.
  • It has a very high capacity adsorption of moisture compared to any other desiccant.
  • More over, it is totally non- toxic. The adsorption capacity is min 70% at RH 99% & 25°.
  • It can be disposed off very easily after use.
  • The clay desiccant pouchesare made up of a very special material “NW fabric / Spun bounded fabric”, which ensures very good breathing for themoistures vapors so as to ensure maximum efficiency of desiccant. Such fabric material does not allowthe water molecules to move out of pouches. Thus once water vapors are absorbed byclay desiccant, it does not allow water to go out of pouches. This is full proof protection of your goods till thetime it reaches the end destination.
  • The results is a tough durablesheet structured with an impressive combination of properties for packagingopportunities. It has excellent tear resistance.
  • It is available in various sizes from 5 gm pouch to 1.5 Kg pouch.
  • Our product meets to International Standards like Mil-D-3464 E.

The big size pouches ( 1Kg- 1.5 Kg) are called as “Eco-desiccant Container dry pouches”.

Container Dry pouches has a large adsorption area as water can be adsorbed from bothsides of the bag. This results in a very high adsorption rate.

The adsorption characteristics of Clay + additives provide Container dry with a superioradsorption capacity, even at low humidity levels, and the ability to effectively protect cargothroughout the entire voyage.

A high equilibrium moisture adsorption capacity of more than 70% at 99% RH.(25°C)ensures that the goods will be protected for a longer period over transportation time fromthe fluctuations of temperature and humidity conditions of the container.

We can also supply high capacity adsorption Heavy duty Desiccant pouches, which has adsorption capacity up to more than 300%. This is the one-time solution for many issues.

Pouches / Quantity needed

The number / quantity may vary depending on the length of the voyage, the range oftemperatures encountered, and the type of cargo protected, free air space in container,nature of packaging material used (wooden pallets, corrugated boxes) etc. However, oncase-to-case basis we can advise suitably to customers based on our experience.


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