Fully recyclable barrier-coated cardboard packaging

Cardboard mono-packaging is perfect for a circular economy as it can be fully recycled in the waste paper cycle. However, if cardboard is coated with a polyethylene (PE) barrier layer, its recyclability is reduced. STI Group supports an alternative option: using special varnish as a barrier coating, which helps to reduce plastic use and maximise recyclability.

Packaging often requires a grease or moisture barrier, particularly when designed to contain food. With cardboard packaging, this barrier is traditionally achieved by applying a thin coating of polyethylene (PE). Consumers often do not recognise at first glance that their cardboard packaging contains a plastic component, but it will certainly be identified at the recycling plant. The PE coating and all the cardboard fibres adhering to it will be sieved out and ‘thermally recycled’ – i.e. incinerated. Potentially recyclable cardboard is therefore being lost along with residual PE waste.

Modern water-soluble barriers that do not reduce cardboard recyclability can be used for food packaging; even if coloured and even if in direct contact with the food. This prompted STI Group to develop its TO GO packaging for fat-containing foods, based on a sustainable barrier varnish instead of PE lining. The varnish enables the inside of the pack to be branded attractively, is naturally food-safe, and is fully recyclable – as demonstrated by TU Darmstadt, using PTS RH021/97 Cat.1 for packaging recyclability.

‘Modern sustainable barriers are helping us to expand the range of applications for fibre-based packaging,’ explains Jakob Rinninger, CEO of packaging manufacturer STI Group. ‘Our approach is based on driving the circular economy and it complements our customers’ sustainability goals of reducing or eliminating the plastic content of fibre-based packaging. We have partnered with our coating supplier WEILBURGER Graphics to develop a monomaterial solution that is suitable for frozen or TO GO products. Both these segments are characterised by above-average growth, so we see great potential for more sustainable packaging solutions that are fully recyclable.’

Developments in the raw materials markets could lead to even greater demand for this innovative type of barrier coating because it is applied as part of the printing process. So, as well as offering improved recyclability, it shortens delivery times. It also allows STI Group customers to access a wider range of cardboard materials for their packaging designs, rather than being restricted to specific PE-coated board qualities.

Innovation booster Circular Innovation

Maximising packaging recyclability by using renewable monomaterial solutions, while educating consumers to make better choices is part of STI Group’s Circular Innovation ethos. Its holistic, strategic approach drives more sustainable packaging development and manufacturing methods. An interdisciplinary team evaluates each new idea in the context of a circular economy and brings effective innovations to market: this move to replace PE coatings with fully recyclable varnish is just one example.

For more information go to www.sti-group.com.

Written by Kevin Gambrill