San Diego —
Electrolux has built a prototype refrigerator using bioplastics.
"But we still have a lot to learn about these materials," said Marco Garilli, innovation expert at Electrolux, in an interview at the 2018 NatureWorks Innovation Takes Root Conference in San Diego.
In the interests of sustainability, he said, Electrolux is also exploring the use of recycled plastics and potential use of bioplastics for durable applications.
Prototype developmentThe initial experimental steps were taken in 2011, but it was not until Electrolux came into contact with NatureWorks LLC that a more structured approach was adopted. The Electrolux Global Connectivity & Technology Center (GC&T) embarked on an ongoing collaboration with NatureWorks.
Over the past several years, GC&T has explored and tested how bioplastics can be applied in Electrolux products and packaging. Together with the Electrolux purchasing and R&D departments for food preservation, the decision was made to develop a prototype refrigerator in which all visible parts were made of bioplastic.
The end product had to meet all the requirements and specifications of a conventional refrigerator, as well as being able to be recycled at the end of life, in order to fit within the concept of the circular economy.
"We looked at all the different plastics used in the refrigerator to see whether they could be replaced," Garilli said. "It became obvious that wherever ABS had been used, this could be replaced by Ingeo PLA. In fact, all the styrenes could be replaced by PLA. We evaluated all the components one by one and found that the shelves, for example, could easily be made of PLA. Instead of using [high impact] PS for the inner liner, we used 20 percent [acrylic] and 80 percent PLA.
"NatureWorks worked closely with us on the development of specific grades for the project," said Garilli, adding that there were a number of challenges that needed to be addressed, such as the low softening temperature of PLA and the fact that it is slightly less transparent than the styrenic materials. Mold shrinkage was another problem that needed to be solved, while another issue was cost.
SurprisesWhen asked about the advantages to using a bioplastic over a conventional plastic, the first thing Garilli pointed to was the environmental benefit calculated by using Ingeo PLA.
"Looking at the plastics used, this prototype refrigerator had a carbon footprint that was 83 percent smaller than when using petroleum-based plastics. Per fridge, this was 22 percent smaller," he said.
However, there were also benefits relating to the properties, chemical and mechanical, of the bioplastic itself.
"When it came to producing the refrigerator liners, which are big thermoformed products, the issue of distortion arises," he said. "There were basically two choices: We could produce the liners by thermoforming extruded amorphous PLA sheet, or we could opt for a PMMA/PLA multilayer liner. As the latter was a known solution, it made sense to use it and to go for a 100 percent PLA solution later, if it worked."
The first surprise was how well it worked.
"During thermoforming, the material is stretched, which results in tension. When using HIPS, a sheet with a thickness of minimally 3.5 millimeters is required to avoid distortion issues. ... We were excited to find that with PLA, this was far more uniform, making it possible to reduce the layer thickness to 1.2 millimeters, which not only meant that less material was used, but also that the weight of the liner was reduced," Frank Diodato, NatureWorks business director, said.
For now, Electrolux has put the project on hold until the time is right for a product launch. According to Garilli, the market will develop, but "when and how this develops depends on various factors, including the interest from the market."
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