PacDry Primary Desiccant
Montmorillonite Clay · US MIL-D-3464E Compliant · Available in 6 Unit Sizes
What is PacDry?
PacDry is a primary desiccant manufactured from Montmorillonite, a naturally occurring clay mineral. It is supplied by DunLash Systems as a single-component, chemically inert desiccant packaged in non-woven paper sachets.
PacDry is sized and rated in International Standard Desiccant Units (ISDU) in compliance with US MIL-D-3464E — the military-grade desiccant specification used internationally for packaging and storage applications.
Primary desiccants like PacDry are designed for use inside primary packaging — instrument cases, electronics packaging, pharmaceutical containers, ammunition boxes, toolkits, sealed storage boxes, and any application where moisture control inside a small, enclosed space is required.
They are used alongside container desiccants, such as DunLash Ultra, rather than as a replacement for them.
Clay Moisture Control for Packaging and Cargo
PacDry clay desiccants provide reliable moisture absorption inside sealed packaging and small enclosed spaces. They help protect moisture-sensitive products from humidity, condensation, corrosion, mould, packaging damage, and product deterioration during storage and transport.
Because PacDry is chemically inert and manufactured from Montmorillonite clay, it is a practical option for customers requiring cost-effective, mineral-based moisture control across industrial, commercial, export, and specialist packaging applications.
Features of PacDry Primary Desiccants
- Manufactured from Montmorillonite clay
- Single-component, chemically inert desiccant
- Packaged in non-woven paper sachets
- US MIL-D-3464E compliant
- Sized in International Standard Desiccant Units
- Available from ½ unit to 16 unit sizes
Benefits of PacDry Primary Desiccants
- Protects moisture-sensitive goods in sealed packaging
- Helps prevent corrosion, mould, and humidity-related damage
- Suitable for small enclosed spaces and primary packaging
- Supports high-standard commercial and military-grade applications
- Helps reduce product damage, claims, and packaging failures
PacDry Technical Specifications
| Specification | PacDry |
|---|---|
| Composition | Montmorillonite clay, single component, naturally occurring |
| Form | Chemically inert granules in non-woven paper sachet |
| Compliance standard | US MIL-D-3464E — Dehydrating Agents, Bagged, Activated |
| Sizing basis | International Standard Desiccant Units, ISDU |
| 1 ISDU definition | Absorbs 6ml water at 25°C / 40% RH; or 3ml at 25°C / 20% RH |
| 1-unit weight | 36g to 40g of Montmorillonite |
| Packaging | Non-woven paper sachet |
Available PacDry Unit Sizes
| Unit Size | Approx. Weight | Sachet Size | Qty per Carton |
|---|---|---|---|
| ½ unit | Approx. 20g | 85 x 60mm | 600 per carton |
| 1 unit | Approx. 40g | 100 x 90mm | 400 per carton |
| 2 units | Approx. 80g | 130 x 90mm | 200 per carton |
| 4 units | Approx. 160g | 190 x 90mm | 120 per carton |
| 8 units | Approx. 320g | 135 x 190mm | 60 per carton |
| 16 units | Approx. 640g | 180 x 220mm | 32 per carton |
How Desiccant Units are Calculated
The ISDU, or International Standard Desiccant Unit, system makes it straightforward to calculate how much PacDry is needed for a given application. Each desiccant unit is defined by its absorption capacity, not its weight. This allows different desiccant types and manufacturers to be compared on a consistent basis.
One unit of PacDry absorbs a minimum of 6ml of water vapour when exposed to air at 25°C and 40% relative humidity, or 3ml at 25°C and 20% relative humidity. For applications requiring higher absorption capacity, larger sachet sizes, such as 2, 4, 8, or 16 units, provide proportionally greater capacity in a single sachet.
Contact DunLash for guidance on the correct PacDry unit size and quantity for your specific packaging volume, product type, and storage environment.
Applications for PacDry Primary Desiccant
- Electronics packaging — prevents moisture damage to PCBs, sensors, and components during storage and export
- Instrument and tool cases — maintains dry conditions for precision instruments, measuring equipment, and professional tools
- Pharmaceutical and medical packaging — where moisture control is a product stability requirement
- Firearms and ammunition packaging — military and commercial applications requiring MIL-D-3464E compliant desiccants
- Agricultural seed packaging — preventing moisture uptake during storage and shipment
- Automotive parts packaging — protecting metal components, bearings, and sensors in sealed export packaging
- Museum and archival storage — protecting documents, artefacts, and sensitive materials
- Food-grade sealed packaging — dried goods, supplements, and shelf-stable products requiring moisture control
PacDry vs DunLash Ultra — Choosing the Right Product
PacDry and DunLash Ultra serve different moisture control functions and are often used together in the same shipment.
| Comparison | PacDry Primary Desiccant | DunLash Ultra Container Desiccant |
|---|---|---|
| Application | Inside primary packaging and small enclosed spaces | Inside 20ft and 40ft shipping containers |
| Desiccant type | Montmorillonite clay | Calcium chloride, CaCl₂ |
| Standard | US MIL-D-3464E | SGS compliant and FCC approved |
| Typical size | ½ to 16 ISDU units | 750g hanging container desiccant bag |
| Best for | Product packaging, instrument cases, sealed boxes, small enclosed spaces | Container-level moisture protection during freight and storage |
Why Choose DunLash PacDry Clay Desiccants?
DunLash supplies PacDry as a high-quality primary desiccant for packaging, cargo, storage, and specialist moisture control applications. PacDry supports customers who need a chemically inert, clay-based desiccant that meets recognised specification standards and is available in multiple unit sizes.
Whether you require desiccants for electronics, instruments, sealed cartons, pharmaceutical packaging, military-grade applications, or moisture-sensitive export products, DunLash can help specify the correct PacDry unit size and quantity.
For container-level protection, DunLash also supplies DunLash Ultra container desiccants. These products can be used together where both primary packaging and container-level moisture protection are required.
Contact DunLash to order PacDry primary desiccants or discuss the right desiccant specification for your packaging requirements.
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PacDry FAQs
Is PacDry safe to use with food products?
PacDry is a chemically inert clay desiccant and does not leach chemicals. However, for specific food-contact applications, verify compliance requirements with DunLash. For container-level food cargo protection, DunLash Ultra with its FCC approval is the recommended product.
Can PacDry be reactivated and reused?
Montmorillonite clay desiccants can technically be reactivated by heating to drive off absorbed moisture. However, for commercial cargo protection applications, single-use sachets are recommended to ensure consistent performance and avoid contamination. DunLash supplies PacDry in sealed cartons for single-use applications.
What is the difference between MIL-D-3464E and standard silica gel desiccants?
MIL-D-3464E is a US military specification that sets minimum absorption requirements and packaging standards for desiccants used in military and high-standard commercial applications. Silica gel desiccants may also meet MIL-D-3464E but must be tested and certified against this specification to claim compliance. PacDry meets this standard.
What is PacDry used for?
PacDry is used for moisture control inside primary packaging and small enclosed spaces, including electronics packaging, instrument cases, toolkits, sealed cartons, pharmaceutical packaging, ammunition boxes, automotive parts packaging, and archival storage.
Is PacDry the same as a container desiccant?
No. PacDry is a primary desiccant designed for smaller enclosed spaces and product-level packaging. Container desiccants, such as DunLash Ultra, are designed for larger enclosed spaces such as 20ft and 40ft shipping containers.
Contact DunLash to order PacDry primary desiccants in any unit size or to discuss the right desiccant specification for your packaging requirements.
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