Flexible packaging (also known as pouches or bags) have recently become popular in many industries that package foods, beverages, medicines, personal care products, and chemicals due to their lower cost and consumer perceived environmental benefits vs traditional rigid container packaging.
Pouches and bags are composed of lightweight materials, often a combination of polyethylene (PE), aluminum, nylon, PET, polypropylene (PP), or paper. Most pouch materials will have one to three barrier layers depending on the product being held.
Pouches can also be upgraded with many enhancements like re-closable zippers, 1 way valves, tear notches, hang holes, and spouts depending on the product characteristics or functional demands.
The characteristics of each film choice for flexible packaging are below. It will help you choose the right material for your product application.
Mono-layer materials are made out of a single layer of polyethylene that varies in caliper depending on the performance demands of the pouch. This plastic will typically be up to 50 microns thick.
A stand-up pouch or any package made out of one single-layer of plastic is easier and cheaper to produce and transport. Since it is made out of one type of plastic it can be recycled much more readily than two/three layer pouches or rigid packaging.
However, a mono-layer pouch is best suited for a product that does not require a lot of barrier protection, such as a bag of granola or nuts.
A 2-ply material has an inner layer of polyethylene and outer layer of typically paper, aluminum, PET, or Nylon. Typically, 2-ply pouches are up to 100 microns thick, but could vary depending on the product.
The inside layer is specifically designed to seal as well as protect the product from air, moisture, and odors. The outside layer is usually specified for barrier performance, durability, or product appearance.
Compared to mono-layer pouch, a two-ply is more expensive to use but more durable. It is also typically not as recyclable as a mono-layer pouch as multiple materials are combined into one product and would need to be separated prior to recycling.
A 3-ply material is a composite laminate that consists of an inner, middle, and outer layer.
Typically, the inside layer consists of PE for sealing, the middle layer is made with aluminum nylon or paper for barrier or appearance, and the outer layer formed with PET for a glossy laminated finish look.
3-ply material shows good durability and strength with typical thicknesses in excess of 190 microns. This material is often used in high barrier applications, such as with chemicals to avoid leakage or contact with air.
Due to its multiple barriers and a complicated manufacturing process, 3-ply is the most expensive material.
Pouches can have added functionality for ease of use or for product requirements.
Below are the most common options that can be added to your packaging.
Zippers are commonly used in flexible packaging materials since they allow consumers to access and reclose products at their own pace, preserving the quality of the product. This also eliminates the need to transfer the product contents into another container for storage.
A degassing valve allows air, carbon dioxide, or other gas pressure to escape from a package without allowing external moisture or oxygen to enter. A valve is useful for products sensitive to oxygen, moisture, or off-gas that could explode in a completely sealed package.
Tear notches are designed to be easy to tear open with a small slit or cut at the end of the closure seal. This will allow for consumers to easily identify where and how to open a pouch package.
A hang hole is a circular hole or sombrero-shaped opening in the top of the pouch material, usually in the middle. It enables your pouch to hang from a display hook for maximum visibility to the consumer. Hang holes are commonly used on small or lightweight products.
Pouches are increasingly being used with spouts for the characteristics of a bottle without the weight of plastic normally used.
Packaging made out of flexible materials can offer the same functionality as many other formats of packages like bottles, but uses far less resources and is in some level more environmentally friendly.
There are many considerations to take when selecting a pouch material, but by reviewing your product characteristics, its weight, and the amount of protection needed as well as any functional requirements you can have an excellent package you can depend on.
For a quick reference on pouch materials refer to the chart below.
Material
Cost
Barrier
Weight Durability
Shelf Presence
Caliper
Mono-Layer
$
Basic
Low
High
50 microns
2-Ply
$$
Medium
Medium
High
100 microns
3-Ply
$$$
High
High
High
190+ microns
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