Moisture can turn a promising shipment into a disaster. It is one of the primary invisible enemies in industrial logistics and storage, capable of causing irreversible damage to a wide range of products. From metal corrosion to electronic failures, exposure to moisture seriously compromises the quality and functionality of goods.
Did you know that a relative humidity (RH) level above 40% inside packaging can lead to corrosion and mould within days?
Thankfully, desiccant bags offer an effective solution. They act as protectors by absorbing excess moisture, ensuring that your products reach their destination in perfect condition, free from unpleasant surprises. In our previous blog post on how to prevent moisture damage using desiccant bags, we explored their functionality and benefits.
In this guide, we’ll delve into the different types and formats designed for the most demanding industrial applications. We’ll show you how these small yet powerful desiccants can make the difference between a successful shipment and a costly setback.
Types of desiccant bags
There are several types of desiccant bags, each designed to suit the specific conditions and needs of different industries. Selecting the right type depends on factors such as ambient humidity, the type of product being protected, and the length of exposure to moisture.
Bentonite clay bags
Bentonite clay is a natural desiccant widely used for its high absorption capacity in low to moderate humidity conditions. It is chemically inert and non-corrosive, making it a safe option for various industrial sectors. Additionally, it is a cost-effective solution, ideal for businesses looking to balance efficiency and cost.
This desiccant can absorb up to 30% of its weight in water vapour, making it effective in applications where there are no significant temperature fluctuations. Its absorption capacity is gradual and stable until saturation. Compared to silica gel desiccants, bentonite performs better in environments with an RH of up to 35%.
However, its absorption ability may be reduced at temperatures above 50°C, so it’s not the best choice for extreme conditions.
Another advantage of bentonite clay is its sustainability. As a 100% natural resource, it is an eco-friendly option that can be safely disposed of in the environment after use.
Typical applications
Bentonite clay desiccant bags are widely used to protect industrial parts, machinery, electronic components, textiles, military products, and medical equipment.
One consideration is that they can release fine dust, so they are not recommended for use with delicate optical equipment, such as cameras, binoculars, microscopes, or fragile materials that could be affected by dust residue.
Sustainability
After use, the desiccant can be safely disposed of in the environment, though the packaging must be discarded appropriately in waste bins.
Silica Gel bags
Silica gel desiccant bags are one of the most widely used solutions for controlling moisture. This synthetic desiccant is notable for its high absorption capacity.
It can absorb up to 40% of its weight in water vapour without altering its physical structure, allowing it to maintain a high level of absorption even in environments with higher RH.
Silica gel is non-corrosive, non-toxic, and dust-free, making it a clean and safe option for protecting sensitive products. While its cost is higher compared to other desiccants, its effectiveness and characteristics justify the investment.
Typical applications
Silica gel desiccant bags are widely used in industrial packaging, as well as for the protection of electronic equipment, pharmaceutical products, textiles, and leather goods.
Bentonite clay vs Silica Gel
Bentonite desiccants tend to be more cost-effective, making them the preferred choice especially for most industrial applications.
VCI desiccant bags
VCI (volatile corrosion inhibitor) desiccant bags offer dual protection for metal products. In addition to absorbing moisture, these bags release VCI molecules that adhere to the surface of metals, forming an invisible layer that prevents corrosion.
This protection is particularly useful for products exposed to prolonged or fluctuating humidity, such as during sea transport or storage in uncontrolled environments.
VCI bags are often used in combination with other VCI materials to reinforce the protection of high-value metal products.
Typical applications
VCI desiccant bags are commonly used in industries such as automotive, steel, and technology sectors. They are particularly effective for storing and transporting high-value metal components that require additional anti-corrosive protection.
Container desiccant bags
“Container rain”, a phenomenon caused by internal condensation, is one of the leading causes of claims in goods transportation. This condition is effectively controlled with the use of container desiccant bags, designed to prevent large-scale moisture damage.
These are large bags with a much higher absorption capacity than standard desiccant bags. They can absorb significant amounts of water, making them ideal for conditions of high RH and constant condensation risk.
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Occasionally, RH levels inside containers can reach 100% due to sharp temperature changes.
These bags are made from a mixture of calcium chloride and a plant-based thickener, providing a high moisture retention capacity. Calcium chloride is significantly more effective and potent compared to other absorbent materials, such as silica gel. However, it is important to note that calcium chloride is not inert and is classified as an irritant, so these bags are intended exclusively for industrial use.
Container desiccants activate when humidity levels exceed 40%, a point at which phenomena like mould, corrosion, and condensation can begin to appear. Their absorption capacity increases exponentially with RH levels, and they can absorb over 240% of their weight in water vapour.
Typical applications
These bags are particularly useful for maritime transport, large warehouses, and routes with prolonged exposure to high-humidity conditions. They are placed inside containers, either hung or above pallets, ensuring effective moisture protection throughout the journey.
Desiccant formats
Desiccant bags come in various formats, designed to adapt to different types of packaging and protection needs. Below are the most common formats.
- Single bags: This is the most standard and versatile format. The bags are placed directly inside the packaging, ensuring even distribution to absorb moisture throughout the environment. Loose bags are ideal for both individually packed items and larger volumes, making them suitable for a wide range of industrial sectors.
- Desiccant chains: These consist of a series of bags linked together in a chain. This format is ideal for placement inside long packages or for covering spaces linearly, such as along a row of products or the sides of a container. Chains allow for an even distribution of desiccants across a larger area, ensuring consistent protection against moisture.
- Adhesive bags: These bags come with an adhesive backing that allows them to be fixed securely inside the packaging. This format ensures that the bags stay in place during transport or storage, preventing them from moving around. Adhesive bags are particularly useful in packaging where space is limited or where order must be maintained during handling.
- Desiccant panels: These are large sheets of desiccant bags that are laid horizontally, for example, over a pallet or on top of goods within a container. These “blankets” are designed to cover large areas and absorb moisture in wide spaces. This format is common in container transport, where moisture can pose a significant problem, and a large-volume solution is required to protect goods during transit.
- Large bags for containers: These bags are designed for large-scale applications, particularly in maritime containers or large warehouses. They have a much higher absorption capacity than standard desiccant bags and are made to absorb substantial amounts of moisture in extreme conditions. Typically placed on the walls or ceiling of containers, they protect goods throughout the entire journey.
These various formats allow businesses to select the best solution for their specific needs, whether for small, delicate items or large industrial loads requiring long-term protection.
In summary, desiccant bags play a crucial role in protecting products from moisture damage, a critical risk in industrial logistics and storage. The variety of desiccants available – such as bentonite clay, silica gel, and VCI bags – allow businesses to address specific needs based on the type of goods, environmental conditions, and exposure time. Each offers unique advantages, from sustainability and low cost to advanced absorption capabilities and large-scale protection against corrosion.
Selecting the right desiccant optimises the supply chain while reinforcing the quality and safety of the product. Understanding the different formats and applications ensures that moisture control solutions are both efficient and cost-effective, contributing to a safe and sustainable logistics process.
We equip your products with top-tier protection, ensuring their quality with specialised desiccant bags. Get in touch now and see the difference!