Additive in new adhesive removes sticky residue on recyclable materials

The adhesive contains thionolactone which makes up 0.25 per cent of the composition. This additive allows the adhesive to be dissolved in the recycling process, which has not been possible until now. According to the University, labels can also be detached up to 10 times faster compared to a non-degradable adhesive. The team’s work is detailed in Angewandte Chemie. 

In a statement, Professor Joseph Keddie, leader of the Soft Matter Physics laboratory at Surrey University and fellow of the Surrey Institute for Sustainability, said:  "Adhesives are made from a  network of chain-like polymer molecules, irreversibly linked together, which leads to the residue build-up we see left behind when recycling materials such as glass and cardboard. 

"The problem of network residues is frustrating on an industrial scale and consequences of insoluble adhesives on the quality of recycled products are of even greater concern. Our solution offers the promise of less challenging and more cost-effective recycling. 

"Our additive creates what we call degradable thioester connections in the polymer network and provides an innovative solution to making recycling processes  residue free." 

Dr Peter Roth, senior lecturer of Polymer Chemistry at Surrey University, and fellow of the Surrey Institute for Sustainability added: "While other degradable adhesives exist, there are none which resemble what is currently used industry-wide in their chemical make-up. We are proving it is possible to use similar adhesives and show that a simple additive has the potential to increase the quality of recycled materials such as glass and cardboard. 

"The next steps would be to look at the commercial viability of this additive, as well as look at the sustainability impact."  

So far, the adhesive has been tested on glass, steel, plastic and paper, including cardboard.