Moisture Barrier Bags: Components and Function

Moisture Barrier Bags: Components and Function
Published On:April 14, 2022 Revised On:September 27, 2023

When transporting fragile medical equipment, food, medicines, or electronics, shipping goods is vulnerable to damage caused by jostling, rolling, shock, bumping, and other factors. Furthermore, suppose the cargo is going overseas. In that case, it may be subject to corrosion, dust, oxidisation, and various other pollutants that can impact everything from the performance of electronics to the “freshness” of food products.

Many businesses use alternatives such as foam inserts or corrugated boxes with corrugated cardboard walls to safeguard their shipment. For an extra layer of security while shipping by sea, whether locally or internationally, it will be beneficial for shippers to use the following:

What are Moisture Barrier Bags?

Unlike air barriers, which slow the movement of air, the purpose of a moisture barrier bag or vapour barrier bag is to block the movement of water vapour. A Moisture Barrier Bag in the packing and shipping industry inhibits condensation, preventing moisture from accumulating on the product. They are available in roll or bag form and customisable to different needs.


  • Protecting hygroscopic products against damage caused by moisture and corrosion.
  • Shielding atmospherically sensitive items from the environment outside the package.
  • Lowering expenses since less desiccant is used results in lower total shipping weight for products. Items are also more likely to arrive in good condition, saving businesses time and money to replace them, resulting in customer satisfaction.
  • Eliminating the need to re-dry goods.
  • Preventing the transmission of odours.
  • Reducing the possibility of product leakage, which means that the cleanliness of the outer packing is optimal – this also allows businesses to reuse any outer containers used for storage and transportation.
  • Perfect for use in any anti-static application.

Typical Applications and Industries:

  • Fine Powders
  • Raw Ingredients
  • Dehydrated / Freeze-Dried Foods
  • Food Supplements
  • Pharmaceutical Products
  • Excipients & Active Ingredients
  • Electronics / Microprocessors
  • Fine Art & Antiques Preservation
  • Drying Packaging

Components and Functionality

Moisture Barrier Bags (MBB) shield products from moisture and static electricity. This protection is enhanced by two key components: desiccants, which absorb internal moisture, and Humidity Indicator Cards (HICs), which indicate moisture levels inside the bag. This article explains how MBBs, desiccants, and HICs function together for effective moisture control.

  1. Moisture Barrier Bags (MBB) function by enclosing a device with a metal or plastic cover that prevents moisture vapour from entering the bag. The bag also protects against static electricity (ESD).
  2. Desiccant is a drying agent packed in a porous pouch to allow moisture to pass through and be absorbed. Therefore, it absorbs moisture vapour (humidity) from the air that remains within the barrier bag after being sealed. The water vapour that enters the bag will be absorbed as well. Even when fully saturated with moisture vapour, desiccant remains dry to the touch.
  3. Humidity Indicator Cards (HICs) are printed with moisture-sensitive dots that change colour from blue to pink in response to different humidity levels. The humidity inside barrier bags may be measured using the HIC. When the bag is opened, the card is checked to ensure it is dry inside. This implies that the barrier bag and desiccant were properly functioning.

Types of Moisture Barrier Bags

Foil Moisture Barrier BagsThese are one of the most popular types of moisture barrier bags. They are made of Mylar, which protects contents from oxygen and moisture damage. They can have a resealable zipper, are lightweight, and protect the contents from light, moisture, and air damage. Due to its high-quality construction, this protective packaging solution resists punctures and rips.

Kraft Foil Moisture Barrier Bags: They have a stronger structure and a layer of Kraft paper and foil to preserve their contents. These bags will also protect the contents from moisture, vapour, and light. They are greaseproof, so they are an excellent choice for businesses that want to use them in an environment prone to grease damage. This is a dependable and effective protective packaging option if severe corrosive damage is concerned.

Static Shield Moisture Barrier Bags: Protect against electrostatic discharges and moisture. It may be the best option for a variety of items.

How to Choose the Moisture Barrier Bags

When looking for the right packaging, there are several aspects to consider:

  • Thickness & Material
  • Special Features Proper Sizing
  • The Specifications of Your Product

These factors depend on the product and the storage conditions for the duration. Furthermore, several products on the market appear identical yet have very different barrier qualities.

1. Material selection

There are a variety of film constructions to satisfy the needs of the business’s goods based on the amount of oxygen, light, and moisture that can safely expose their product. When choosing packaging, it is important to analyse these considerations and how the product will be preserved. The idea is to select a material that provides enough barriers to appropriately protect the goods without spending too much money on unnecessary films.

Industries such as food, pharmaceutical, biomedical, and electronics all require this type of packaging. In-process components, medicinal goods, dehydrated/freeze-dried food products, and other products susceptible to moisture or oxidation are examples of products that will benefit greatly.

2. Product Compatibility

The material used should be chosen based on the product to be packaged. For example, strong chemicals and fine powders have highly precise requirements for the film’s inner layer. Chemicals, as well as natural components like lemon, include compounds that can react with certain films.

Along with establishing product compatibility, the product must also have the capacity to be sealed using a sealer machine, as certain products create a residue that makes heat sealing difficult. Fine powders and greasy products are examples of such items. Therefore, the most effective option is a film with an advanced inner layer capable of sealing right through substances/residues for such objects.


From safeguarding sensitive electronic components to preserving the freshness of perishable goods, these bags play a pivotal role in many sectors. Their multi-layered design, tailored to offer resistance against environmental adversities like humidity, dust, and electrostatic discharge, underscores the profound understanding of various products’ challenges during storage and transit.

Moisture barrier bags are the ideal choice for packages shipped by sea to protect items from the humid sea environment, ensuring that items arrive just as they left. Stream Peak supplies customized moisture barrier Bags (MBB). We provide high-quality bags designed to prevent moisture and static electricity intrusion. We also offer complementary components like desiccant packs and humidity indicator cards (HICs) for enhanced moisture control. Contact us for an appointment with our engineers for a no-obligation packaging consultation.