Printing packages with light

Can we make food packaging more sustainable? Sterre Bakker (TU/e) recently published her results in journal ACS Applied Optical Materials. In collaboration with BASF, she looked at waterborne coatings that change colour when illuminated with UV-light, so-called photoresponsive coatings. She tried to make environmentally friendly waterborne coatings on paperboard, suitable for packaging. Is it possible to make such a coating, and use it to print optical patterns on the packages?

Sterre used waterborne coatings, as they can be more environmentally friendly. The use of waterborne coatings allows the emission of harmful volatile compounds to be greatly reduced. The use of photoresponsive waterborne coatings, however, has been studied less extensively so far.

In her publication, Sterre shows the results of two different methods of making a photoresponsive waterborne coating. It turns out that both methods are suitable for creating a coating that allow the print of optical coatings like images or text. These patterns fade over time; how long the pattern lasts, depends on how it is stored. When stored at room temperature the pattern lasts a few hours, but when stored in the freezer, it lasts up to several weeks.

Sterre’s results show that it is possible to make waterborne coatings that can be printed on using UV light. These coatings can be used in, for example, packaging of frozen foods, showing how long food has been stored at a certain temperature. Additionally, the coating showed good water barrier properties, which can come in quite handy when making food packaging!

At 27 January, Sterre will defend her thesis. We wish her good luck in the final part of her PhD trajectory, and of course during her defence!