Darren Dodd, Service and Marketing Director at Selig, asks how sustainable are your packaging seals?
The recent shift of Coca-Cola to tethering caps on disposable PET bottles of their iconic soft drinks shows how much packaging design is on the move.
With the environmental agenda challenging packaging designers to rethink everything, even the way containers are sealed is under the spotlight. Here’s what every company who uses packaging seals in their production process needs to be aware of.
Packaging seal successes
A well-sealed product means shelf-life expansion, reduced wastage, and tamper evidence possibilities. These are three of the main reasons that a sealing method known as ‘induction heat sealing’ has grown in both size and importance across the globe over the past few decades. In fact, think about opening any food or vitamin jar and most of your consumers will have come across such a seal.
Its popularity as a sealing method has increased even more in recent years, thanks to the growth of ecommerce. Producers have moved to induction heat sealing to overcome increasing leakage issues, and many international shipping companies now require the use of induction liners on liquid products to protect their distribution channels.
All change?
However, despite induction heat sealing being able to meet the challenges presented by many wide and varied distribution networks, environmental pressures are driving a shift in the materials used in the liners. At present, many induction heat seal liners used on bottles and jars are made from multiple materials. They can be recycled using chemical recycling but need to be separated from the container to allow the full package to be fed into the recycle stream.
With this in mind, there is growing demand for common materials for the container and the seal, to ensure it can be recycled as a whole. To do this, the humble liner is being re-envisioned. The challenge is now on to develop liners that are simpler, more recyclable and contain more recycled content, whilst also continuing to protect consumers from spoilage and leakage.
Responding to the challenge
Selig is working with customers to improve recyclability in a number of ways:
First matching liners with the products they are being supplied in, so that no residual foreign material is left on the container or cap. Taking coffee as an example, more and more producers are opting to switch the board back liner – which is found in the coffee’s plastic cap – with a plastic one that matches the cap, so it doesn’t contaminate the recycling stream.
Secondly, the way that the liner seal separates from the container is being adjusted to ensure that clean removal is possible. This makes the container easier to recycle, without contamination, as well as the cap.
Thirdly, Selig is working to take the recycling concept a step further, aiming to develop ways to help create a ‘mono-material whole product’. This means creating PE liners for PE bottles, PET liners for PET bottles etc. However, developing ‘mono-material whole products’ that include a liner, aren’t as straightforward as they sound, particularly because laminated liners offer specific sealing and production line speed benefits that end users and producers alike have come to expect.
As can be seen, it looks like retailers, producers and packaging manufacturers will still have to navigate a range of challenges when it comes to deciding where the boundary lines are for packaging recycling and functionality. However, with consumer pressure for sustainable solutions continually on the rise, the stakes are high and the risk of failure costly – even when it comes to the humble sealed liner.
