The one-hour Webinar covered the more technical topics of how to work on circularity via debonding adhesives on demand and chemical recycling of plastics
Following our first successful live online session about collaboration and benchmarking data, Afera continued the 64th Annual Conference kickoff with a second Session on the more technical angles of how to work with circularity: creating new possibilities for debonding-on-demand and using hydrocracking to turn to feedstock the huge chunk of plastics in the value chain that are not yet recycled. Afera Strategist and Session Moderator Bert van Loon observed that we are talking about creating efficiency in the debonding and repurposing process, and if not there, then in the chemical recycling process further down the line. Over 80 tape professionals participated in the hour-long interactive seminar.
Hydrocracking technologies and their potential for circularity
By Felix Bobbink, co-founder and CEO of Plastogaz
How do we close the loop with chemical recycling?
What do we do with the value chains of today that are still too linear or semi-circular—the ones which have a huge gap because of the materials which cannot be properly recycled? This gap could be worth €30 billion by 2030. Plastogaz develops (and would like to license) catalytic technologies for the transformation of waste plastic materials into value-added products (new raw materials) in an attempt to close the loop. Based in Switzerland, Plastogaz is an Ecole Polytechnique Fédérale de Lausanne (EPFL) spin-off company founded in 2020 by 4 experts in sustainable chemistry and catalysis.
When it comes to plastics or chemicals in general towards circularity, there are 2 main areas that are being explored: bio-sourcing plastics or chemicals (e.g. the Plastogaz founders have worked on biomass refining or CO₂ valorisation) or creating a circular economy from the crude feedstock working back to the building blocks (e.g. what Plastogaz does with plastic waste hydrocracking, which they believe is the most promising avenue).
Hydrocracking involves converting the feedstock (e.g. a mixture of plastics) in the presence of a catalyst (a material which enables chemical transformation) and hydrogen. The result is that the plastics are very nicely cut into shorter hydrocarbons. The point of hydrocracking is that contrary to pyrolysis, you can control the selectivity of the process by finely tuning the process conditions and catalyst, deciding when to stop the hydrocracking. Short hydrocarbons are used as precursors to polyolefins.
Their chemical recycling process was demonstrated on a laboratory scale (100g), and pilot operations at industrially relevant quantities are scheduled. Complex materials such as tape have been successfully transformed into the high-quality, clear liquid product of naphtha – as opposed to a dark oil worth more as fuel than in material applications. Naphtha can be used in downstream chemical processes towards the synthesis of new polyolefins. Mr. Bobbink explained how the composition of glues and additives used in tapes influences process efficiency (i.e. whether pre-processing is required), potentially aiding in redesigning tapes towards chemical recycling. Testing ultimately determines how well a material or mix of materials will work in hydrocracking.
How do adhesives react to hydrocracking?
Depending on the chemical structure of adhesives or molecules in general, they react under certain process conditions. In hydrocracking, you need to reach a temperature of about 350˚C, at which Mr. Bobbink suspects some adhesives will start to decompose. The products of the decomposition may deactivate the catalyst. The mechanism of deactivation is being investigated so that the process can be improved. Mr. Bobbink’s ambition is for hydrocracking to work on all types of adhesives.
In innovation, circularity and sustainability, can you have your pure IP even if you need the help of many stakeholders early in the process of creating your technology business?
Yes, but this works when the core business of each of the parties is not exactly the same. Mr. Van Loon noted that Afera is trying to facilitate this kind of collaboration, in which everyone can benefit, while ensuring the protection of individual interests.
Do we know which solution at which cost delivers which contribution to recyclability and circularity?
Mr. Bobbink said his academic background is in biomass and CO₂ valorisation methods for making chemicals. He and his team have calculated a preliminary life cycle analysis for their process as well as financial models on the technology at scale. You have to achieve a good balance between sustainability and profitability using the hydrocracking technology. Knowing today what solutions will deliver the largest contributions in the future is challenging. For example, bioplastics appear very promising, but they make up 1% of the market share, an amount which is actually quite small. This means that even if it were profitable, the logistics of sourcing so much biomass to fill the gap are really difficult. So, according to Mr. Bobbink, this is an open question and explains why there are so many people working on all aspects of recyclability and circularity.
About Felix Bobbink
Dr. Felix Bobbink holds a PhD in catalysis from the Ecole Polytechnique Fédérale de Lausanne. Throughout his scientific career, he has studied the transformation of waste feedstock (ocean biomass, CO₂, plastic waste) into value-added products. After completing his PhD, he founded Plastogaz as an EPFL spin-off, where he is currently CEO.
Perspectives on (the future of) debonding
By Maxime Olive, innovation and industrial property manager, debonding expert at Rescoll
Mr. Olive described the strategies and potential solutions for the current trend of debonding applications, which include maintenance, end-of-life, temporary fixing and ecodesign. With such European Directives as those covering end-of-life vehicles, electronics and consumer goods over the last 20 years, regulatory pressure on how goods are disposed of has accelerated the need for recycling, especially of new and widespread dissimilar assemblies and coated materials. Easier maintenance and recovery of parts are also desired to extend product lifespan and to close the loop in manufacturing.
Debonding/stripping-on-command, which Mr. Olive says is actually a paradox, offers options to engineers and designers for materials assembly, but there are several requirements of a debondable adhesive that are not easily met: It must be similar in processing and service to the standard adhesive used for the application, and it must debond easily, quickly and cleanly. So the challenge is finding a compromise between durability and the release function. Debonding of standard adhesives is mainly based on thermal degradation of the adhesive, cutting of the adhesive, use of solvents and a combination of these methods, which can be time-consuming, invasive/damaging to the substrates, toxic to handlers and complex. There is a clear need for easy, quick and reliable debonding techniques based on switchable adhesives.
So far, different technical approaches have been developed for debonding an adhesive on command: through either modifying resins with intrinsic debonding features (modified backbone) or adding specific fillers/additives to the adhesive. Nitto and tesa both make products with expandable agents (as described in some of their patents), and Mr. Olive recommends additional academic reading on examples of both approaches.
Rescoll has developed its own patented, thermally triggered debonding primer called INDAR. It is compatible with all adhesives without affecting their high mechanical properties during service life, but once thermally triggered on-demand, the primer activation of the adhesive allows for an easy and clean disassembly. An acceptable test margin of ageing and environmental conditions confirms INDAR’s performance. It has worked well, for example, on the debonding of composite foil fixed to the steel frame of the engine of a SEAir boat and in many other uses in the automotive, aeronautical, electronics and fashion industries. INDAR is limited to a range of thickness of several microns, so working on a nanometre scale would be really challenging. Rescoll is also involved in the “DECOAT” European Project (HORIZON 2020 Research and Innovation Programme) to remove topcoats and top layers from materials such as plastics, foams and textiles for easier recycling.
Still little is known about adhesion and durability of high-performance adhesives. Access to information on debonding is limited as there are few products on the market, and keywords are misleading (e.g. “debonding” often stands for “delamination”). Adhesives may be considered for applications where the lack of reversibility is not possible. This also goes for coated materials, such as plastics, at end-of-life. Strategies and incentive for debonding/stripping-on-demand depend on product value and service life in addition to end-of-life. In most cases, working on easy separation and reuse of similar materials has more impact than working on biobased materials.
About Maxime Olive
With 16 years of experience in the adhesive industry, Mr. Olive started out at Rescoll as R&D engineer. He specialises in formulation issues and debonding-on-demand strategies. From 2010 to 2015, he was team manager of the sustainable chemistry department at Rescoll. Mr. Olive’s activities range from adhesive dismantling strategies to smart adhesives formulations. Since 2015, he has been IP and innovation manager at Rescoll.
How are Plastogaz and Rescoll theoretically linked?
Mr. Olive said that if you take bonding assemblies, different substrates will denote different waste streams for recycling or reuse. But if you first use a debonding technology on the market to separate products, you can provide waste for a new stream for Plastogaz, for example. Dissimilar assemblies can be complex, so Plastogaz’s hydrocracking technology can be made easier if they have a well-controlled waste stream that begins upstream with a good debonding technology.
For recycling, the idea is to remove impurities from the surfaces of the substrates. When they trigger the primer, there is very little residue on the substrate, and this is easy to wash away. For nonporous substrates, such as glass, composite and metals, they can become so clean after being primed and washed that you cannot tell the difference between a new and refurbished substrate. But the quality and value of the parts of the article may determine the business case for debonding it. Plastogaz’s hydrocracking technology (or another destructive method) typically comes in when the quality of the substrate has been decreased or compromised to an extent to which you cannot reuse the parts.
The business cases of recycling: One of the upcoming foci of regulatory pressure in Europe is tacking non-intentionally added microplastics. How do you see your technologies in light of this?
Mr. Bobbink said the idea of Plastogaz’s technology is to bring low-quality plastics back to high-quality. These high-quality plastics should release fewer microplastics than when the quality is lower. But he feels this question is more related to microfiltration than hydrocracking technology. Mr. Olive said that through his debonding technology, it is possible to avoid the release of offending plastics, because we can separate and send them into their correct waste streams for recycling.
The following sponsors of this year’s Conference were thanked for their support:
Mr. Bobbink’s presentation can be downloaded here. Mr. Olive’s presentation can be downloaded here. The recording of the Session can be accessed here using password (no spaces before or after): B1W^0.8z