All About Flexible Barrier Materials

Types of Materials

Whether your task is to protect cultural heritage items like paintings or tapestries from environmental damage, to extend the shelf life of food items, or or prevent corrosion on a piece of equipment being export shipped; choosing the correct material is a critical aspect of protective flexible packaging. At Heritage Packaging, choosing the proper material for your application is our specialty.

As a converting company, we typically work with flexible packaging materials that are classified as either mono-layer blown films, co-extruded blown films, or multi-layered laminated materials.

• Mono-layer blown films look like a typical clear poly bag. They are made by melting a particular resin, or multiple resins and additives, then forcing that melted blend of ingredients through an extrusion dye, and blowing up the extruded material into a tubular film that gets flattened and wound onto a core.

• Co-extruded blown films are made in a similar manner but with two or more blends being extruded simultaneously into the tubular configuration. When looking under a microscope, the film has clearly distinguishable layers. These co-ex films offer greater barrier properties than mono-layered films.

• Multi-layered laminate materials are a combination of two or more pre-manufactured films or other material, like foil, paper, TYVEK, Polyester, or  NYLON, that are bonded to one another by either adhesive, polyethylene, or a solvent. Laminated structures currently offer the highest level of barrier protection over the two flown film categories- more layers mean a more robust material with a higher barrier.

There are hundreds of different flexible packaging materials available within these categories. Among them, some are additionally categorized as Mil-Spec materials. 

Mil-Spec materials can be mono-layer film, co-ex film, or multi-layered laminations. Still, to be certified as a Mil-Spec material, the manufacturer must submit the film for government testing against a specific performance standard. If approved, it’s awarded inclusion on the Qualified Products List for that standard. (i.e. MIL-PRF 131, MIL-PRF 121, etc.) 

Any structure that is submitted for testing and approved can then be printed with the necessary Mil-Spec nomenclature and sold as Mil-Spec material, but the manufacturer can also elect to forgo that printing and sell the material for strictly commercial applications.

Whether or not a Mil-Spec material is required depends on your application’s specifications. Unless specified for a commercial application, there are often other comparable options available; however, Mil-Spec materials CAN be used for commercial applications if desired.

Laminate Structure

Multi-layered laminates often look alike but are NOT the same. Their strengths are determined by the layers that make up the laminate, and each layer serves a specific purpose in keeping desirable elements in a package (like flavor, aroma, or a controlled atmosphere), and undesirable elements out (like moisture vapor, oxygen, or other harmful elements).

A typical film/foil/poly laminate is made up of five layers:

1. Exterior Strength Layer

2. Adhesive or Extrudate

3. Barrier Foil

4. Adhesive or Extrudate

5. LLDPE Polyethelyne Sealant Layer

Marvelseal®, CadPak N, and CadPak P are all examples of multi-layered laminates like this.

Stronger film/foil/poly laminates include extra strength-layers. The layers may include:

1. Exterior Strength Layer

2. Adhesive or Extrudate

3. Barrier Foil

4. Adhesive or Extrudate

5. Buried Strength Layer

6. Adhesive or Extrudate

7. LLDPE Sealant Layer

Examples of laminates with extra strength-layers are PBN7 and VF-45.

The Wrong Barrier Material

The wrong material can damage your products or goods. Not all laminates are suitable for the same application, and it’s important to consider the qualities of what you’ll be protecting and/or preserving before choosing what material to use. 

Consider these things when choosing a barrier material:

• Will the material off-gas?

  • If yes, will the off-gassing damage the tangible item?

• Has lab testing been conducted on the material?

  • If not, has the material been widely used in other industries for tangible items with a similar makeup?

• Does the material provide enough barrier to the surrounding environment?

  • Remember, there are sometimes a variety of barrier materials that are suitable for protecting your items. It is important to learn about multiple materials, so you can make an informed decision about how much of a barrier is required.

• Is the material robust enough for the given application?

  • Some items with sharp corners will require a more puncture-resistant material, while other tangible items are so delicate that a stronger material, combined with other features like a vacuum pull, could destroy the contents. This is partially why highly customized packaging solutions are imperative to preserving critical products and goods.

Now that you know a little more about flexible barrier materials, we hope you feel confident choosing the right flexible packaging solution for your application.

Have more questions or want to know more about the products we manufacture using materials like the ones discussed today? Send us an email or visit heritagepackaging.com/quote to speak with our team of packaging experts.