A sticky solution: how using adhesives to create alternative packaging is helping to reduce plastic waste

The volume of plastic waste produced globally is set to triple by 2060, according to a new report from the Organisation for Economic Co-operation and Development (OECD), which warns that radical action will be needed to curtail the mountains of plastic piling up across the world.

Everyone involved in the plastics chain, from packaging manufacturers to consumers, will need to play their part. As David Attenborough says: “If we start doing those small steps that are easily achievable, we can before long really have an effect.”

The figures are stark. Single-use plastics, mostly used in product packaging, are used once then thrown away and account for half of the 400m tonnes of plastic waste produced globally each year. Less than 10% of plastics are recycled, with much of the waste heading for landfill, littering the oceans and threatening wildlife. The race is on to find alternative forms of packaging and to improve recycling.

But “simply demonising plastic is not the answer”, says Matthias Schaefer, corporate director of global packaging engineering for the Adhesive Technologies business unit at the multinational Henkel. “There is no silver bullet to this problem. Plastic will continue to play an important role in packaging for some time to come as it is lightweight and extends the shelf life of food, among others. But we urgently need to find alternative packaging materials and make plastic packaging easier to recycle. I don’t believe we have a plastics crisis so much as a waste crisis,” he says.

Schaefer points out that much of the crisis stems from a lack of recycling infrastructure in developing nations. While plastic recycling is low globally, it has advanced strongly in recent years in developed countries. The UK is estimated to have recycled 51% of its plastic waste in 2020, so is still short of the industry goal of 70% by 2025. And globally there is even further to go.

Companies such as Henkel, the chemical and consumer goods company behind familiar names such as Schwarzkopf, Loctite and Pritt, recognise this – and, in Henkel’s case, finds itself combatting the plastic waste issue on two fronts: it is working to reduce plastic and designing for more recyclability in its consumer brands businesses while needing to innovate solutions for customers as a supplier.

Henkel spokespeople Matthias Schaefer (left) and Philippe Blank (right)
Henkel spokespeople Matthias Schaefer (left) and Philippe Blank (right)

So it’s a sticky problem – and it may have a sticky solution. Philippe Blank, circular economy lead for Adhesive Technologies at Henkel, says there are a wealth of ways that Henkel’s adhesive technologies can use its expertise to help.

Henkel has created a glue-based alternative to the shrink-wrap plastic used to hold boxes in place on warehouse pallets. Thin, adhesive strips are placed on each box of product so that they can stick to each other on the pallet and hold fast. That has the potential to save thousands of tonnes of plastic wrapping.

Another recent innovation is the KeelClip, a cardboard alternative to the classic plastic rings or shrink wrap used to hold together multipacks of cans, such as beer. KeelClip has been developed in cooperation with Graphic Packaging International (GPI) and uses Henkel technology.

Then there is surface treatment technology for enhancing paper to give it similar qualities to plastic – this includes adding functional barriers and coatings to make paper grease and liquid resistant. Despite adding this layer, the paper remains recyclable in existing paper recycling processes. This is an example of Henkel’s EPIX technology, a portfolio of materials that make paper more suitable for packaging in place of plastic.

A major problem in recycling is packaging that is made from a variety of materials. Lightweight flexible packaging often consists of several layers made from different plastic types, for instance a polyethylene (PE) layer, a polyethylene terephthalate (Pet) layer, and sometimes an aluminium layer to protect the product and extend its shelf life. “Given its valuable properties, flexible packaging will remain an important packaging solution,” says Blank. “But we need to improve the design by moving towards mono-material construction, yet keeping the advantages of today’s flexible packaging. Such a move will simplify the recycling process.”

And the industry is already moving to single-material packaging, but this may involved six or seven layers of PE that must be laminated together using adhesives. “We make much of that adhesive and here it is important to build on the right chemistry – even though the adhesive only makes up 5% of the weight, it can still pollute the recycling process when the product is melted into pellets,” says Blank.

“That is where we have solutions that are improving the recycling quality by building on the right chemistry in the adhesives to make them compatible with the recycling process.”

Another approach to improve the circularity of flexible packaging is debonding, where Henkel and its partners are actively developing optimised adhesives for advanced recycling processes to separate these various layers. Recovering the materials in essentially their original form (be it PE or PET) allows for recycling of high-quality materials. These can then be used again in, for example, food packaging.

Epix mailer at door - Henkel has launched its EPIX technology, a portfolio of materials that make paper more suitable for packaging in place of plastic.
Henkel’s EPIX technology makes paper more suitable for packaging in place of plastic – and it can still be recycled

Henkel has also developed an alternative to bubble mailers, the envelopes with inner plastic bubbles that protect the contents in the post. Combining paper and plastic makes them hard to recycle as the two products interfere with recycling for each. Henkel’s solution has been to replace the bubble plastic with a cushioning technology that protects goods and is recyclable in the standard paper stream.

The multitude of innovations seen at Henkel are just part of the picture when it comes to solving the issues facing the world. Tackling the triple planetary crisis of global warming, biodiversity loss and waste means balancing the impact of plastic across all three. While plastic waste may add to the waste mountain and threaten biodiversity in ocean environments, plastic generally has advantages. In packaging, they keep food safe and fresh, thus reducing waste, and are lightweight to transport, saving fuel and cutting greenhouse gas emissions.

“What we are trying to do is look at the bottom line. Circularity plays a major role and we need to adapt to reality and to develop the recycling infrastructure, and do everything we can to create new ways of doing things,” says Blank.

Schaefer adds: “To solve this problem, we are all going to have to change our habits. Businesses will need to create recyclable packaging, local authorities will need to provide the recycling infrastructure and consumers will have to choose the right bins for each piece of waste. This will require a combined effort.”

Find out more about how Henkel is aiming to transform its business by moving to a circular economy through science and innovation