Demand for mono-materials in packaging has been growing as the industry moves from a linear to a circular economy. We spoke to Lorena Rodríguez, researcher at the Functional Printing and Coatings Department of AIMPLAS, and asked her about challenges and possible solutions.

-Have you observed a growth in the use of mono-materials in the packaging industry, and if so, what do you think lies behind that growth?

Nowadays, there is a paradigm change, from a linear to a circular economy, to ensure there’s enough food, water and prosperity in 2050. The aim is to ensure healthy and safe living and working conditions, and cause less harm to the environment, and it has been shown bad plastic packaging management it is one of the major factors contributors to the environment damage.

According to the European Strategy for plastics in circular economy, in 2030 all plastic packaging must be recyclable. Taking this into consideration, the packaging industry is making great efforts to reach the 2030 date with completely recyclable packaging structures to reduce the environmental damage caused plastic could do.

A few years ago, the 70% of the packaging structures were multilayer structures, because ‘there isn´t a single material with the desired properties’ the packaging should have for its final application. Nowadays, it has been necessary to change packaging structures to mono-material that can be recycled and thus comply with the guidelines set by the EC for the 2030.

-What, in your opinion, are the sustainability benefits of mono-materials?

Mono-materials structures benefits are based on their recyclability. Mono-material packaging can be collected and enter a waste management flow to obtain raw material from a residue for a different application, thus contributing to the circular economy.

-What are the challenges and limitations of mono-materials for packaging applications?

Mono-material structures for packaging application challenges are based on the improvement of their properties, i.e. mechanical and barrier properties.

Other materials commonly used in the mono-material packaging structures like adhesives and coating need to have functional properties apart from their basic properties. In the case of adhesives and coating there is a big challenge to improve the barrier properties.

-Can you talk about innovations that have managed to address that issue?

Innovation is based on solving the limitation the materials show. In the case of mono-materials, mechanical properties or sealability have to be improved in order to be used in the ‘mechanical property layer’ or in the ‘thermosealed layer’ in a multilayer mono-material structure.

In the case of the coatings and adhesives, the main innovations are based on improvement of the barrier properties, O2 ad H2O. This improvement in the barrier property in coating and adhesive are related to simplifying multilayer packaging structures, and the improvement of mono-material packaging structures.