What is Activated Clay?

What is Activated Clay?
Published On:November 19, 2021 Revised On:February 13, 2024

Desiccants are hygroscopic substances that remove moisture from the air within a sealed environment, protecting packaged goods from humidity-induced damage such as mould, corrosion, and spoilage. Their application spans various industries, including electronics, pharmaceuticals, food, and textiles. By absorbing and holding particulate water, desiccants help preserve product quality, performance, and shelf life during storage and transport.

Understanding Activated Clay

Activated clay desiccant, montmorillonite clay, is a naturally occurring mineral derived from bentonite clay. It consists mainly of aluminium phyllosilicates mixed with small amounts of other minerals, such as calcium, magnesium, and iron, contributing to its characteristic high adsorption capacity.

The “activation” process involves heating the clay to remove any inherent moisture, increasing its porosity and surface area, thereby enhancing its ability to absorb moisture. Unlike silica gel, another common desiccant, activated clay is affordable and can adsorb moisture at a wider range of temperatures, making it a versatile choice for various packaging needs.

Properties and Mechanism

Activated clay is characterised by its natural mineral composition, primarily montmorillonite. This mineral is known for its layered structure, which contributes to its high surface area and porosity—key attributes for effective moisture adsorption.

Physically, activated clay appears as small, granular particles that can vary in size, depending on the application. Chemically, it is stable and inert, so it does not react with the products it protects. This stability is crucial for food and pharmaceutical packaging applications, where chemical reactivity could be a concern. Its adsorption capacity is affected by temperature and relative humidity, performing best in environments with high relative humidity levels.

The moisture adsorption process of activated clay desiccants is primarily physical, relying on the capillary action of the clay’s porous structure. When exposed to humid air, water molecules are drawn into the spaces between the layers of the clay particles. This process is facilitated by the surface charge of the clay particles, which attracts the polar water molecules. Unlike chemical adsorption, the water is not chemically bound to the clay, allowing for moisture release under certain conditions, such as elevated temperatures, which can be used to regenerate the desiccant for reuse.

Benefits of Using Activated Clay

Cost-effectiveness and Affordability: One of the benefits of activated clay desiccant is its cost-effectiveness. Compared to other desiccants like silica gel or molecular sieves, activated clay is generally more affordable due to the abundance and availability of the raw materials from which it is made.

Environmental Sustainability: These desiccants are derived from naturally occurring bentonite clay, making them more environmentally friendly than synthetic desiccants. They do not contain chemicals that could harm the environment when disposed of, making them a more sustainable choice for companies committed to reducing their ecological footprint.

High Moisture Absorption Rates: While they are particularly efficient in high humidity conditions, their ability to absorb moisture without becoming too quickly saturated allows them to maintain protective atmospheres over extended periods. This high moisture absorption rate ensures that products remain dry and undamaged, regardless of external conditions during storage or transit.

Reusability and Regeneration: When the desiccant reaches its moisture capacity, it can often be regenerated by heating, driving off the absorbed water and restoring its drying capacity. This process can be repeated multiple times, extending the life of the desiccant and further enhancing its cost-effectiveness. The ability to regenerate activated clay desiccants reduces waste and contributes to more sustainable packaging practices.

Applications of Clay Desiccant

Electronics and Electrical: Moisture is a significant threat to electronics and electrical components, potentially causing corrosion, short circuits, and other damage that can impair functionality. Activated clay desiccants are commonly used in packaging to absorb excess moisture and protect sensitive components during storage and transport. Their ability to maintain a dry environment ensures that electronic products reach consumers in optimal condition, enhancing reliability and extending product life.

Food and Pharmaceutical Packaging: In the food and pharmaceutical industries, controlling humidity is crucial to prevent spoilage, maintain efficacy, and extend shelf life. Activated clay desiccants help control moisture within the packaging, preventing mould growth, bacteria, and other contaminants. Their natural composition makes them a safe choice for direct contact with food and drugs, ensuring that these products remain dry, fresh, and safe for consumption over extended periods.

Leather Goods and Textiles: Leather goods and textiles are particularly susceptible to damage from excess moisture, leading to mould growth, fading, and deterioration of material quality. Activated clay desiccants are used in the packaging of these products to absorb humidity, preserving their quality, appearance, and texture. By maintaining a controlled environment, activated clay helps ensure that leather and textile products remain pristine.

Metal Parts and Machinery: Rust and corrosion are common concerns when storing and shipping metal parts and machinery, especially under varying environmental conditions. Activated clay desiccants effectively absorb moisture from the air, protecting metal surfaces from the corrosive effects of humidity. Their use in packaging metal parts and machinery is critical for preventing rust, ensuring that components remain functional and maintain their structural integrity over time.

Selection and Sizing for Packaging

The effectiveness of activated clay desiccant in protecting products from moisture-related damage heavily depends on selecting the appropriate type and amount for specific packaging applications. This selection process involves considering various factors, including the product’s moisture sensitivity, the packaging’s volume, and the environmental conditions it will encounter. Proper calculation and strategic placement of the desiccant are crucial for optimal moisture control.

Factors Influencing the Choice of Desiccant

  • Moisture Sensitivity of the Product: The inherent moisture sensitivity of the product being packaged is a primary consideration. For example, electronics, pharmaceuticals, and food products have different tolerance levels for humidity. The more sensitive a product is to moisture, the greater the need for a desiccant with high moisture absorption capacity.
  • Packaging Volume: The size of the packaging space directly influences the amount of desiccant needed. A larger volume requires more desiccant to effectively absorb moisture and maintain the desired humidity level within the packaging.
  • Environmental Conditions: The external environmental conditions, including temperature, humidity levels, and the duration of exposure during storage and transit, also play a critical role. Packages exposed to higher humidity levels or fluctuating temperatures may require more desiccant to compensate for increased moisture intrusion.

Calculating the Required Amount

The amount of activated clay desiccant needed for a particular packaging application can be estimated through a basic calculation considering the abovementioned factors. While specific calculations may vary depending on the desiccant manufacturer’s guidelines, a general approach is as follows:

  1. Determine the Total Volume of the Packaging: Calculate the internal volume of the packaging container in cubic feet or cubic meters.
  2. Assess the Moisture Intrusion Level: Estimate the potential moisture intrusion based on the packaging material, seal integrity, and expected environmental conditions. This can be categorised as low, medium, or high.
  3. Select the Desiccant Factor: Manufacturers typically provide a desiccant factor, expressed in grams per cubic foot or cubic meter, based on the moisture intrusion level and the product’s moisture sensitivity.
  4. Calculate the Required Desiccant Amount: Multiply the total volume of the packaging by the desiccant factor to determine the total amount of desiccant needed.

Placement and Integration

Effective moisture control also depends on the strategic placement and integration of the desiccant within the packaging design:

  • Accessibility: Place the desiccant where it can easily absorb moisture, typically near air inlets or areas prone to moisture accumulation.
  • Protection: Ensure the desiccant is placed in a way that does not interfere with the product or become compromised during shipping and handling. Desiccant sachets or packets should be secured to prevent shifting and damage.
  • Integration: Consider integrating desiccant materials into the packaging design, such as desiccant liners or pads, to maximise space efficiency and moisture absorption effectiveness.

Types of Packaging

  • Pouches: Activated clay is often packaged in small, permeable desiccant pouches made from materials like Tyvek, non-woven fabric, or paper. These pouches allow moisture to pass through and be absorbed by the clay while keeping the desiccant contained and preventing direct contact with the product. Pouches are available in a range of sizes to accommodate different packaging volumes and moisture control needs.
  • Canisters: For applications requiring a more robust solution, activated clay desiccants can be packed into rigid canisters. These canisters are typically made of plastic and feature a perforated design that allows air to circulate through the desiccant material. Canisters are commonly used in pharmaceutical bottles, dietary supplement packaging, and other applications where limited space and moisture control are critical.


The utilisation of activated clay desiccant in packaging plays a pivotal role in safeguarding a wide array of products against the detrimental effects of moisture. This natural, cost-effective solution offers unparalleled benefits, ensuring that goods remain dry, intact, and preserved from the point of manufacture through to delivery to the end consumer. The importance of activated clay desiccant spans various industries, from electronics and pharmaceuticals to food, textiles, and metal parts, providing a versatile and reliable method for moisture control.

At Stream Peak Vietnam, we specialise in high-quality activated clay desiccants. Our production process for clay desiccant bags is certified under ISO 9001 and ISO 14001 standards, reflecting our commitment to quality and environmental management. We ensure the reliability of our products through daily quality assessments conducted in our in-house laboratory. For further information or to discuss your packaging needs, our team of packaging engineers is readily available to assist you.

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