Barrier Coatings Can Unlock Reams of Possibilities In Flexible Paper Packaging

The solution to the many challenges posed by plastic replacement can only be found by innovative barrier coatings. Image courtesy of Parkside.

By Steve Halford, Product Development Technologist at Parkside

So much of the modern packaging industry’s focus is on reducing plastic use.

This is not without good reason. Today’s packaging market is subject to tightening legislation across the world, aimed at cutting the amount of plastic packaging waste that is produced. Measures like the EU’s Packaging and Packaging Waste Regulations (PPWR), India’s single-use plastic ban, and the single-use plastic bans of varying scope that are spreading across several U.S.[1] are becoming more widespread, and broader in scope, as the plastic waste crisis continues to grow.

These measures are carried out with the broad support of consumers around the world, with a recent Ipsos study finding 87% of people agree it’s important to reduce the amount of plastic produced globally, while the same number say that types of plastic that can’t easily be recycled should be banned.

This sounds simple in theory, but the reality is more complex. And the solution to the many challenges posed by plastic replacement can only be found by innovative barrier coatings.

The Uncomfortable Truth about Plastics

An unfortunate truth that the packaging industry has to deal with is that plastic is a highly functional barrier material. It is light weight, low-cost, durable and can be used to create a hermetic seal. All of these attributes ensure it can help prolong the shelf life of perishable food like fresh meat, dairy and produce when incorporated into packaging.

Replacing all of these properties at once is difficult, and the challenges involved in doing so mean that plastic will likely always play some role in the global supply chain. This is a good thing, as while the world’s plastic problem is severe, and does need to be addressed, in terms of carbon emissions it pales in comparison to the global food waste crisis.

UN data estimates that roughly a third of all food produced worldwide is wasted, and up to 10% of global greenhouse gas emissions are the result of producing food that is never eaten. [2] Just 1kg of food waste sent to landfill produces the same number of emissions as 25,000 500ml plastic bottles.[3] Packaging’s main role is to prevent waste by protecting and preserving its contents through the supply chain, not to generate waste itself. All of this means that replacing a plastic pack with an alternative that does not perform adequately through the supply chain can be counter intuitive.

Lightweighted, flexible materials use fewer materials and are more efficient to transport through the supply chain than rigid plastic packages. Image courtesy of Parkside.

A Double-Edged Sword

As a result, reducing plastic in packaging is something of a double-edged sword that requires careful consideration when handling. Paper makes for the obvious choice when looking for a replacement material, as while it does not naturally possess many of the qualities that make plastic such an effective packaging material, it can acquire similar properties through innovative lamination and barrier coating techniques and materials.

Another option is to look at lightweighted, flexible materials rather than rigid packs, which inherently use fewer materials and are more efficient to transport through the supply chain. Flexible paper laminates therefore present a promising solution for many businesses, as they combine material reduction and logistical efficiency with plastic replacement.

It is important that this is achieved without compromising the recyclability of paper. Paper’s high recycling rates[4] make it an attractive choice for brands and packers looking to reduce the overall environmental impact of their portfolios, so adopting paper material that is treated with non-recyclable flexible plastics is a suboptimal solution.

Overcoming Barriers with Barrier Coatings

One viable solution is to use flexible paper treated with a vapour deposition of aluminum. This creates a metallized barrier against oxygen, water vapor, and grease without impacting the recyclability of the pack, as the relative amount of aluminum used is tiny.

Advancements in water-based barrier coatings also mean that the performance of recyclable and compostable flexible packaging has improved dramatically over recent years. This has unlocked new and exciting applications for recyclable and compostable solutions that simply would not have been possible previously.

For example, we developed a solution using a water-based barrier coating that inhibits the formation of ice crystals when frozen. As packaging naturally thaws and refreezes on its journey through the cold chain, the presence of ice crystals can degrade the performance of the grease and moisture barrier coating layers. By repelling ice crystals, these barriers remain intact, enabling the creation of functional, freezable, fully recyclable paper flexible packaging for challenging applications like seafood.

Layered barrier coatings can also be combined with heat seal coatings to help improve efficiency on the packing line. This can be used to create bags and pouches that seal neatly on form, fill, and seal lines, reducing production defects and waste.

As barrier innovation continues to drive improvements in the functionality of paper packaging, the global supply chain’s reliance on plastic to protect goods lessens. Step by step, and pack by pack, improvements in barrier coatings will unlock new possibilities in the fight against plastic waste.

About the Author

Steve Halford is a Product Development Technologist at Parkside. Parkside is an innovative packaging solutions provider specializing in compostable, recyclable, paper-based and innovative plastic flexible packaging solutions for the food, personal care, household care and tobacco sectors. Established for over 40 years, the company is a global supplier. Learn more at www.parksideflex.com.

References

1. https://becompostable.com/advocacy/united-states-legislative-map/
2. https://www.unep.org/resources/report/unep-food-waste-index-report-2021
3. https://www.zerowastescotland.org.uk/resources/rankin-turning-lens-true-impact-food-waste
4. https://www.afandpa.org/news/2023/us-paper-and-cardboard-recycling-rates-continue-hold-strong-2022