ES Gel Container Desiccant Strips with Calcium Chloride

ES Gel Container Desiccants

ES Gel is a strip of sachets in a nonwoven sheath, with a hook for hanging inside the container. The modified starch in the filling binds the calcium chloride solution into a gel.

• Active substance: 60% calcium chloride (CAS 10043-52-4) with modified starch
• Design: strip of 6 sachets of 125 g each in a nonwoven sheath, with hook
• Filling weight: 750 g
• Sachet material: Tyvek® and PE/PP laminate
• Dimensions with sheath: 1140 x 145 x 20 mm plus 80 mm hook
• Absorption capacity: up to 360% of the filling weight, i.e. up to 2.7 l of water per strip (23 °C, 95% relative humidity, 42 days)
• Packaging: 12 strips per carton, strips in plastic bags
• Shelf life: 24 months in the original, unopened packaging

The absorption capacity was measured at 23 °C and 95% relative humidity over 42 days. In a container, the amount of water absorbed depends on air temperature and humidity, transit time, the type of cargo and the packaging used.

Comparison of Filling and Design

All three container desiccants we supply work on the basis of calcium chloride. In ES K and ES Clay, the filling is bentonite clay impregnated with calcium chloride, with ES K containing more of it. Water is bound in the granules, which do not swell after saturation. In ES Gel, calcium chloride is not carried on a mineral support but is the main component of the filling, and modified starch binds its solution into a gel that is retained in the sachet.

The absorption values in the table come from measurements under different conditions, so they cannot be used to compare the products directly or to calculate the number of units for a container.

Absorption Capacity of ES Gel over Time

ES Gel absorbs water gradually. At 23 °C and 95% relative humidity, the absorption capacity is 134% of the filling weight after 7 days, 300% after 28 days and 358% after 42 days. In this measurement, the absorption capacity was still increasing between day 28 and day 42. The amount of water absorbed in a container depends on the transport conditions.

Which Desiccant to Choose

For most shipments, we recommend ES Gel: the smallest number of units is needed per container, and the desiccant is also designed for routes of up to 60 days. ES Clay is used for transit times of up to 30 days, mainly in 20′ containers with low-moisture cargo. ES K is designed for routes of up to 60 days with high-value goods and where the strength of the bag matters.

How Many ES Gel Desiccants Does a Container Need?

The number of desiccants depends on the container size, the type of cargo, the packaging used, and the transit time and conditions. For dosage purposes, moisture-releasing cargo means goods that contain moisture and release it during transport: food and agricultural commodities such as grain, flour, coffee, cocoa, sugar or nuts, as well as fresh wood and goods on which mould has previously appeared. Low-moisture cargo includes, for example, metal, machinery, plastics, electronics, furniture and products made of dry wood.

The values in the tables apply to cargo in tight packaging, without wooden pallets and crates, on a route through a temperate climate. One strip is a complete ES Gel unit of 6 sachets; the total filling weight is given in brackets.

20′ container

40′ and 40′ HC container

Transit time covers the period from loading to unloading, including waiting time in ports. For transit times over 60 days, we calculate the quantity for the specific shipment.

More desiccants are required for low-moisture cargo on wooden pallets, in crates or in cartons, for routes through the tropics and across the equator, in the rainy or monsoon season, for containers carried on deck, when loading in rain and when the container floor is wet. For a transit time of up to 30 days, this means up to 11 strips for low-moisture cargo and up to 16 strips for moisture-releasing cargo in a 20′ container, and up to 20 and 28 strips respectively in a 40′ container. The quantities given are a starting point; the shipper should confirm that they suit the specific cargo.

Installation in the Container

Take the strips out of the plastic bag immediately before installation, because the desiccant starts binding moisture as soon as it comes into contact with air. Distribute them evenly on both side walls and near the doors, and hang them vertically on the hooks in the upper part of the walls, at least 25 mm from the cargo. Do not place the desiccants on the container floor.

Container Rain and Cargo Sweat in Shipping Containers

Moisture in a container may come from the air, pallets, packaging, auxiliary materials and the cargo itself. During sea freight, the container passes through changing temperature and humidity conditions. When the walls and ceiling of the container become cooler than the air inside, water vapour may condense on them.

This is how the phenomenon known as container rain occurs: water droplets forming on cold container surfaces may fall onto the cargo. Moisture also condenses directly on the goods when they are cooler than the surrounding air. This is known as cargo sweat. This increases the risk of wet cartons, corrosion of metal parts, mould growth and damage to the transported goods.

ES Gel desiccants reduce the amount of water vapour in the air inside the container and thereby limit the risk of condensation.