The basic and first step in plastic recycling is the initial sorting. The more pollution and indigestible material that goes to the next step, the more expensive and more complicated it becomes to produce a raw material that can be used for new products. It is then necessary to make greater use of purification measures as well as new additives.
The Chalmers project Recycling of collected plastic from packaging will study both how to develop the sorting step and how the plastic can be upgraded through modifications in the later stages of the recycling process. Based on the results, there is an expectation to be able to develop guidelines for the formation of new products, for example adapted process parameters for extrusion and injection molding.
Technical capability will give the industry confidence in the use of recycled plastic
When it comes to the sorting process there is an interest in studying the purity of the plastic. Initially, the focus will be on so-called near-infra-red (NIR) technology, which is a technique where you can determinate which polymers the collected products consist of. The plan is to collaborate with Swedish Plastic Recycling in Motala, which is one of Europe's largest and most modern sorting plants. Other supplementary sorting techniques, in addition to NIR technology, may also be included in the study.
After the plastic is sorted, there will also be studies on the continued treatment in order to further improve the quality and predictability. Based on detailed studies, guidelines will be drawn up for suitable processes and process parameters for the production of suitable granules that can be used as raw material by industry.
– By reducing the uncertainty about the technical ability of recyclable materials, our expectation is that this project will lead to greater confidence in recycled plastic materials," says project manager Professor Antal Boldizar.
The project also includes production of some selected products in so-called demonstrators. The work with demonstrators will include detailed process studies, mainly of advantageous process parameters in both extrusion and injection molding with regard to microstructure and functional properties of the products. Examples of interesting functional properties are mechanical and thermal properties, shape accuracy, tolerances, surface character and durability.
By 2030, in Sweden, all plastic packaging shall consist of renewable or recycled material
As the collection and sorting of plastic packaging increases in society, it is becoming increasingly important to develop the market for recycled plastic. The organization Swedish food retailer federation recently presented a roadmap where plastic packaging will be produced from renewable or recycled raw material before the end of 2030. Therefore, setting standards and quality standards for both sorted plastic waste and recycled plastic are important industrial issues.