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Water-based adhesive for a zero-waste economy

A new technology that reduces dependence on polymers and volatile organic compounds and increases recyclability of bottles and their labels.

Reducing dependence on VOC-based adhesives

Adhesives are materials used in many manufactured products. Adhesives contain not only polymers, but other chemicals that may be harmful or hazardous such as volatile organic compounds (VOCs).

The dependence on VOC-based adhesives has significant environmental detriments. There are also risks posed by flammability and toxicity.

Water-based adhesives are an environmentally friendly alternative to conventional solvent-based adhesives. But they might struggle to retain adhesive propoerties in humid conditions. And it can be difficult to recover previously bnded materials through reusing or recycling.

 

A water-based reversible adhesive

A positively charged polymeric (polycationic) material will adhere to a negatively charged one (polyanionic) until a suitable change in pH occurs. Previous demonstrations of this phenomenon were not scalable and required advanced synthesis processes.

We have developed a water-based and reversible adhesive.

It works through emulsion polymerisation, consisting of two separate formulations: one containing a polycation and the other a polyanion.

Emulsion polymerisation allows the use of inexpensive commodity materials. It is scalable, and is already used in industrial processes.

The mechanism of adhesion is simple. One surface is coated with the polycationic emulsion. A second surface is coted with the polyanionic emulsion. When both surfaces come into contact, electrostatic adhesion occurs and the emulsions dry. After drying, adhesion is retained in water, and it only fails when the local pH changes.

Applications

An adhesive showing these characteristics is critical for recyclable products, particularly bottles and their labels.

Currently, plastic bottle de-labelling involves several steps. Friction, large volumes of water, and compressed air are all used.

Due to unreliable adhesive removal which subsequently makes labels unrecyclable, waste labels are primarily landfilled. This contributes to land and water pollution, further emphasising the need for a new technology.

Other industries such as packaging or e-waste requiring dismantling and repurposing of parts could also use this adhesive.

 

More information and contact

If you'd like to know more about this technology, this blog delves into its transformative potential, explores its origins, and outlines future development plans.

Find out more about the researchers who developed the glue:

Contact

To dicuss this technology please contact: