Material, Design for Recycling, Circular Economy, Sustainability, Recycling

r-PS in a circular economy

22/07/2021 | 3 min read
Tobias Strasser

With its goal to include as much recycled material as possible in its products by 2025, Greiner Packaging believes in material diversity. Much of the afternoon of the first of its virtual Innovation Days was devoted to different materials, including r-PET, r-PP, and bio-waste materials. Here we review a session about the opportunities created by recycled polystyrene (r-PS).

The future of food contact: circular polystyrene

Tobias Strasser, Managing Director of Greiner Packaging Switzerland, and Jens Kathmann, Secretary General at Styrenics Circular Solutions (SCS), discussed how extending closed loop food contact recycling beyond PET bottles to new food grade applications using recycled polystyrene (r-PS) is now achievable.

“Styrenics Circular Solutions works on unlocking polystyrene’s unique potential for full circularity – by deploying game-changing technologies and solutions. Food grade quality recycled polystyrene delivers all the processing and environmental advantages of polystyrene, with the added value of being a fully circular polymer with a favorable ecological footprint.” said Jens Kathmann

“Polystyrene is well known and has multiple applications for food packaging and food contact. When recycled, it can be easily sorted into its different types and precise sorting allows for tight control of properties of the recyclate for intended applications.”

He explained the process for developing post-consumer PS feedstock for dairy applications.

Starting with the sorting of PS packaging waste, the objective is to separate non-food contact white HIPS (High Impact Polystyrene). With screening and the application of near-infra-red (NIR) technology, 97% can become food-contact white HIPS. By adding intelligent sorting technologies, this can be improved to 99% food-contact white HIPS.

This process takes waste out of the environment, and moves us away from the old linear ‘take, make’ principle, and towards a circular, closed loop approach.

Jens Kathmann, Secretary General at Styrenics Circular Solutions (SCS)

He then described the three main low-energy PS plastic-to-plastic recycling technologies used by SCS to create closed loop PS recycling for food contact quality material, and commented that all of them have a significantly lower CO2 footprint compared to virgin production and incineration. Food contact mechanical recycling is already well known and similar to the process used for PET; Dissolution is an environmental-friendly process which enables the purification of mixed plastics by selective dissolution,

producing high quality recyclate; and depolymerization enables virgin quality r-PS, resulting in material which can be chemically recycled over and over again.

SCS performed successful challenge tests with the super-cleaning technologies of NGR and Gneuss, which confirmed polystyrene as highly recyclable to food grade standards via mechanical recycling. Following the excellent challenge test results, a first application for EU authorization of mechanically recycled polystyrene as food contact material has been filed. Generally, EFSA has six months after receiving the valid application to adopt its opinion and first questions have already been received.

With the same processing behavior as virgin polystyrene in extrusion, form, fill & seal (FFS), r-PS is a confirmed drop-in solution for converters and brand owners.

Polystyrene’s intrinsic capacity for full circularity

“The message: ‘Move to Zero. Zero Waste. Zero CO2. Powered by styrenics’, refers to polystyrene’s unique food contact closed loop recyclability and its very favorable environmental footprint proven by a Life Cycle Analysis of food contact r-PS,” he said and then handed over to Tobias Strasser who presented the success of a recent product trial using r-PS.

Excellent progress has been made in fulfilling polystyrene’s intrinsic capacity for full circularity. We can now confirm r-PS as a drop-in solution for yogurt cups. In processing, it behaves like virgin material with no adjustments needed, and with the same productivity of the equipment. It has the same look, feel, and snapability, with no smell or taste effect on the yogurt.

Tobias Strasser, Managing Director of Greiner Packaging Switzerland

“We have already successfully used r-PS to make yogurt cup multipacks. Working with M-Industry – part of Switzerland’s largest retailer Migros – and the country’s largest dairy company ELSA-Mifroma Group, our K3® cardboard-plastic combination now uses 100% mechanically recycled PS with 100% recycled cardboard, for the first time.”

“The filling process of r-PS yogurt cups at ELSA went smoothly without changing any parameters. The r-PS yogurt cup has the same properties, look and feel as if it was made with virgin PS, and passed all tests: from shelf-life and logistics, to sensory tests, where none of those involved noticed any sensory difference as a result of using the new r-PS material.”

“While we are seeking European approvals with EFSA, we are also in progress with gaining authority here in Switzerland. With positive opinions, we are sure that we can soon go onto the market with this product.”


Watch the full live session here!

Please note: In order to watch the live session you need to login (and register) first; registration is still possible, even though the event is over.

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