Stop Container Rain Before It Reaches Your Cargo
Clariant Container Dri® II is a high-performance calcium chloride cargo desiccant that absorbs up to 300% of its own weight in moisture — locking it in a thick, no-spill gel that keeps shipments dry from loading dock to delivery.
The Problem: Container Rain Is Costing Shippers Millions
Every day, millions of shipping containers cross oceans — and a meaningful percentage of them arrive with damaged cargo. The culprit isn't rough seas or mishandling. It's moisture.
When a container is loaded in a humid environment, the air inside holds a significant amount of water vapor. As the container moves into colder climates, encounters a cold front, or cycles through overnight temperature drops, the interior walls cool down. If that surface temperature falls below the dew point — the temperature at which the air can no longer hold its moisture — condensation forms on the walls and ceiling of the container and drips onto whatever's below. Shippers call this "container rain," and it causes caking of powders, corrosion of metal parts, mold on agricultural and food products, peeling labels, warping of wood, and general packaging deterioration. It repeats with every weather change over a multi-week voyage.
One industry analysis put moisture damage at roughly 12% of affected container loads — in a 1,000-container example at $25,000 per container, that's $3 million in cargo loss. For shippers of sensitive goods, the math for prevention is straightforward.
How Container Dri® II Works
Most desiccants focus on reducing relative humidity. Container Dri® II does something more targeted: it actively lowers the dew point temperature inside the container, keeping it consistently below the container's surface temperature. When there's no dew point crossing, there's no condensation — and no container rain.
The active ingredient is calcium chloride, a compound that absorbs moisture far more aggressively than traditional silica gel — especially at the high humidity levels common in tropical shipping corridors. As it absorbs, the calcium chloride transforms from granules into a thick, stable gel that locks moisture in place. There's no liquid to spill, no risk of dripping onto cargo, and no re-release of moisture as temperatures fluctuate. Under the most demanding conditions (95% relative humidity at 40°C), a single 125-gram bag absorbs approximately 500 grams of water — more than 400% of its own weight.
The Federation of Cocoa Commerce's guidelines for container shipping of cocoa beans specifically recommend calcium chloride desiccant at a minimum loading of 65%. Container Dri® II meets or exceeds that threshold, and its absorption advantage over silica gel is particularly pronounced at the high-humidity conditions where protection matters most.
Configurations
Container Dri® II is available in multiple formats engineered for different loading situations. Royco stocks several configurations — contact us if you're not sure which format fits your shipment.
Pole format (500g, 750g): A rigid hanging desiccant designed to suspend from the eye hooks inside a shipping container. Positioning the desiccant high in the container — near the ceiling, where warm humid air collects — makes this the most effective placement for dew point control over a long voyage.
Container Dri® II Plus (1,500g): Large-format bags with integrated carabiners that clip directly to container eye hooks. Fewer pieces to handle at loading: 3 bags for a 20-foot container, 6 bags for a 40-foot container. Good choice when installation speed matters or when shipment quantities are high enough that bag count becomes a logistics factor. (Download Installation Instructions)
Hard-shell pack: A rigid-shell format that can be suspended or surface-mounted inside a container. The shell protects the desiccant from physical contact with cargo and makes removal straightforward at the destination.
Individual bags with adhesive backing (125g, 140g): Flat bag format with peel-and-stick adhesive strips for direct attachment to container or pallet sidewalls. Works well as a primary solution for smaller shipments or as supplemental protection around specific cargo areas within a larger container.
Adhesive strip format: A wall-mount strip configuration for applications where hanging desiccant isn't practical. Compatible with metal, wood, and corrugated surfaces. (Download Installation Instructions)
Blanket format: A flat desiccant blanket that adheres directly to cargo surfaces or cardboard slipsheets for uniform coverage across flat pallet loads of sensitive goods.
What It Protects
Container Dri® II is non-toxic, Dimethyl Fumarate (DMF) free, and meets FDA specifications for direct contact with food and pharmaceutical products. It is used across a wide range of cargo categories: agricultural goods including coffee and cocoa beans, canned and packaged food, pharmaceuticals and nutraceuticals, electronic components, automotive parts, powders and bulk chemicals, furniture and wood products, glass and ceramics, machinery and metal parts, and general manufactured goods. For defense and government contractors, it is appropriate for use in any container shipment where moisture protection is specified but no military packaging specification governs the desiccant format itself.
Why Calcium Chloride — Not Silica Gel
This comes up often enough that it's worth addressing directly. Silica gel has been the default cargo desiccant for decades, and it works adequately in moderate conditions. But it has two meaningful limitations for container shipping.
First, silica gel's absorption capacity tops out at roughly 20–30% of its own weight under typical conditions. Calcium chloride absorbs 300% or more — a substantial performance difference when you're trying to maintain dew point control across a six-week ocean voyage.
Second, silica gel physically adsorbs water vapor and can release it again when temperatures rise. Over the repeated temperature cycles of a trans-oceanic voyage, this means silica gel may be re-releasing moisture into the container at exactly the moments when condensation risk is highest. Calcium chloride chemically absorbs moisture into a stable gel that doesn't release. Once it's absorbed, it stays absorbed.
The performance gap between the two technologies is most significant at the high humidity conditions that make container rain a real risk in the first place — which is precisely when you need the desiccant to work hardest.
Sustainability
Container Dri® II carries the Clariant EcoTain® label, awarded to products that demonstrate outstanding sustainability advantages across their full lifecycle. For organizations with responsible procurement programs or ESG reporting requirements, this provides a third-party sustainability credential for your desiccant specification. The product is non-toxic and approved for disposal with normal industrial waste — no special waste stream or hazardous materials handling required at the destination port.
Installation and Disposal
Installation is straightforward regardless of format. Carabiner and pole formats clip directly to container eye hooks; adhesive formats peel and stick to the wall surface. Most configurations take under two minutes to install per bag. When the voyage is complete, fully saturated bags contain a solid gel and can be disposed of with regular industrial solid waste. No special handling, no HAZMAT designation, no additional disposal cost.
Get the Right Configuration for Your Shipment
The correct type and quantity of Container Dri® II depends on your container size, cargo type, voyage duration, and the humidity conditions at your origin port. Our team at Royco can help you work through those variables and get you a fast quote on the right product in the right quantity.
Call us at 1-800-677-6926 or email sales@roycopackaging.com
We'll try our best to respond same day.
Container Dri® is a registered trademark of Clariant, registered in many countries. Royco Packaging, Inc. is an authorized distributor.