The end starts at the beginning
Intelligent sorting with digital watermarks
Unfortunately, plastics and foams are all too often still incinerated or even sent to landfill. Where products are recycled, this is usually done through mechanical recycling. Under this system, the plastic waste is initially separated by the consumers, before being sorted by type of plastic, washed, melted down and then processed into recycled materials. These recycled materials are then used as the starting materials for new products and replace plastics made from new materials. Waste can only be fully sorted if we as consumers first separate our waste properly. Innovative technologies such as developing and using digital watermarks on plastic packaging are playing an increasingly vital role in making this sorting process more efficient. It is already clear that digital watermarks will be essential on the packaging market and in Europe’s sorting facilities in the future when it comes to recycling.
Since 2017, we have been involved in the HolyGrail project as part of our work with the Ellen MacArthur Foundation. As a partner of the HolyGrail 2.0 Initiative, managed by the European Brands Association (AIM), Greiner Packaging supports the use of digital watermarks in the designs of various packaging systems: Greiner Packaging employees develop intelligent K3® packaging that makes digital sorting at facilities easier. Crucially, this more precise sorting also improves the quality of the recycled materials. However, it requires corresponding technical innovations at the sorting facilities.
Yet as difficult as implementing this is, how this intelligent digital sorting works is simple: If the plastic packaging ends up at a sorting facility after being used, disposed of and collected, high-resolution cameras detect the digital watermarks of the different types of plastic. The various codes are read and the packaging is automatically sent to the right sorting stream depending on the properties of the product. This ensures that flows of waste are strictly separated by type and ensures high-quality recycled materials, in turn contributing to better efficiency and sustainability in the value chain.
Turning our backs on black waste
Continuing to increase packaging recycling rates requires packaging solutions targeting recyclability that are developed from the start of the product’s life onwards. However, the “design for recycling” concept is being put to the test primarily for black plastic packaging. This is because the dye used means that optic sensors at the waste sorting plants cannot correctly identify and sort black products.
The carbon black masterbatches cannot be detected under the sorting plant’s near infrared module (NIR), which is responsible for ensuring that products are correctly sorted. Accordingly, the plastics cannot be assigned to the right group of waste. To address this shortcoming, together with partners we developed an innovative solution for black plastic packaging that is fully recyclable. Its slogan is “carbon free”. The new packaging material uses an alternative black dye that does not contain soot particles and can therefore be detected.
The German Cyclos-HTP Institute, which specializes in the classification, assessment and certification of product recyclability, has already confirmed that the soot-free black dye is effective for plain plastic bottles. Tests conducted by our customer Henkel also found that bottles that had been dyed black using this method are fully identifiable after removing the perforated sleeve and can therefore be sorted into the right group of waste and then reused.
For more successful chemicals recycling
There is no change to the chemical structure of the plastics during mechanical recycling. Chemical recycling, by contrast, takes exactly the opposite approach and is therefore an important addition to mechanical recycling. It makes it possible to recycle plastics that cannot yet be recycled or at least not satisfactorily. This includes waste made out of different plastics or that contain impurities and plastics that cannot be efficiently sorted. Chemical recycling helps reduce the share of plastic waste that ends up at landfill or being incinerated. It may also result in new products that meet the highest quality standards.
Research has already been going on for years into chemical recycling processes such as pyrolysis and gasification as potential alternatives to simply burning plastics. These processes are not cost-efficient, which is why there has not yet been a major breakthrough. Given this, our goal is to do everything we can to ensure that chemical recycling does not remain merely a theoretical concept and instead makes its way into practice, allowing this form of recycling to play a part in helping create a functioning circular economy.
Asa Kelly (Greiner Bio-One)
Quality Control Technician
CHASE – research cooperation for more recycling quality
New sustainable business requires new thinking and research in different sustainability categories. Here research cooperations between industry and science are becoming increasingly important. This is particularly true in respect to chemical recycling. In Austria, the so-called COMET centers promote such research cooperation. In 2019, the CHASE competence center was opened, with Greiner as a cooperation partner. The research focus at CHASE is the need the chemical industry has to develop more agile, more flexible and more synergistic production methods, while at the same time reducing its carbon footprint, energy consumption and waste production. Currently CHASE is examining how high-quality recycled materials can be gained, despite a wide range of different plastic products, materials and processes. CHASE is collecting data knowledge along the entire process chain, so as to allow a holistic quality control. For Greiner, the results from this research mean that flawless products can be manufactured, also independently of the quality of the recycled materials.
Food packaging: Ending the recycling impasse
The devil is in the detail – including and in particular for chemical recycling. The use of recycled materials in new packaging is subject to very strict quality standards and a zero tolerance policy towards material contamination of any kind by the European Food Safety Authority (EFSA). This means that only a very small portion of mechanically recycled waste is suitable for being made into new food packaging material. This applies particularly to heavily contaminated plastic waste.
One alternative for particularly heavily contaminated plastic waste would be to use chemical recycling. Using current technology, however, this is possible only with very high-quality waste. To break this recycling impasse and have the greatest possible impact on sustainability, Greiner Packaging’s GPOil project is taking an entirely new approach, starting with waste that is of a very low quality but available cheaply and in large quantities around the world. From this material, which has not yet been recyclable, and which is generally incinerated in cement or waste processing plants, we are attempting to produce food-grade material, i.e. high-quality raw material which can be reused for food packaging. Together with partners in the Upper Austrian consortium for raw material procurement and processing, we are currently developing the necessary production and processing technology. The objective of this innovation is to cover our annual recycled materials requirements of more than 20,000 tonnes, thus making another decisive step in the direction of the circular economy.
From foam into oil, gas, coke and electrical power
Chemical recycling of foam compounds for mattresses, padding and technical foams is also related to as yet unsolved technical challenges. The general difficulty is that polyurethane (PUR), the starting material for foams, is very difficult to melt and to break down into its initial components. Various PUR mixtures and organic impurities resulting from use make chemical recycling more difficult. However, together with our partner institute at Trier University, we have made progress in developing a process for hydrothermal carbonization (HTC) on a laboratory scale. Further development projects in the chemical recycling area are ongoing. After all, in HTC, particles similar to coal are formed, which are well suited as starting material for thermochemical conversion processing (pyrolysis). For the pyrolysis oil as well as the pyrolysis coke and gas gained in this way, there would be application possibilities in the petrochemical and industry (tires, rubber production, pigment pastes), in the form of activated carbon or in generating electricity using gas engines. Here too we will establish further development steps over the next few years, ensuing, together with our partners, that chemical recycling of foams is a markable and sustainable disposal option.