Engineering Insights: Start Testing Sustainable Plastics Now to Meet Future Demand
According to Todd Stevens, Senior Technical Development Engineer at M. Holland, demand for sustainable plastics like biopolymers and post-consumer recycled (PCR) plastics is “burgeoning.” Todd has worked with PCR and biopolymers since the late 1980s and, until now, efforts to increase adoption have mostly failed.
“I’ve seen three different waves of PCR adoption and they’ve all lost their momentum. This time it’s different,” Todd confirmed. “You can’t ignore sustainable plastics anymore. There is so much more public support for sustainable products and more legislation in the works that will mandate its use. These are just the early innings of a long game.”
Today, some states have regulations requiring a minimum amount of recycled content in products — like California’s Assembly Bill 793 — that are expected to impact plastics manufacturers. As these regulations continue to gain popularity, plastics processors should start testing alternate materials now to improve the sustainability of their products in advance of new requirements and increased demand.
Testing Sustainable Plastics
“When your customers begin to ask about sustainability, it’s an indication that testing should have begun yesterday,” Todd said. “It takes time to perfect plastics processing when switching from a virgin material to a sustainable one, such as PCR. The physical properties of the finished part may be inferior when fully substituting sustainable for virgin, so changes in material selection may be required.”
Biopolymers and recycled plastics can often be partially substituted in the same applications as virgin materials without affecting the integrity of the product. Post industrial recycling (PIR) feedstocks can also be explored if PCR is not an option, allowing processors to take what is essentially scrap and convert it into viable products.
Todd and M. Holland’s team of technical development engineers work with customers during the sustainable material testing process.
“We receive many PCR and sustainable product requests and that’s very encouraging. But because recycled and bioplastic materials are inherently different from their virgin counterparts, the qualification process can be somewhat arduous” Todd said. “Extensive processing, product performance and multi-lot validation studies increase the prospect for success.”
The biggest challenge for PCR substitution is that product purity is not 100% and lot-to-lot inconsistencies can make it difficult to adjust. If you’re ready to begin testing, Todd recommends setting realistic goals to maintain performance and processability. Finding the right mix of virgin and recycled material will require more experimentation than processors expect.
Processors that set out to incorporate small amounts of PCR are able convert to a new formulation on a more immediate basis. Others, who want a higher level of PCR incorporated or have more challenging product specifications, could require years to completely the transition to a new formulation. For a high level of incorporation, processors and their customers need to be all-in on sustainable plastics for the long run.
“On the first try, you’ll likely find that recycled material doesn’t meet your quality standards or performance expectations.” Todd explained. “As you continue to work with sustainable materials and become more familiar with the process, you can increase the amount of material used, but I recommend a less than 25% inclusion rate to start.”
Sustainability by Design
If sustainable plastics are not a fit for your business now but you still want to meet emerging customer demands, consider how you might improve the recyclability of your products instead. Processors can design for recycling by consciously modeling their products to ensure the best recyclability and quality of their recyclate by following set industry guidelines.
“Plastics, more specifically thermoplastics, are inherently sustainable. They can be recycled many times,” said Todd. “In their virgin forms, polyethylene and polypropylene are the most recyclable, while polyvinyl chloride (PVC) and polystyrene (PS) are less recyclable.” If virgin resin is required but sustainability is still the goal, Todd recommends creating products using only one recyclable resin. “Simplified mono-material structures, such as all polyethylene or all polypropylene, can replace multi-material structures to immensely increase potential recyclability.”
Acknowledging the Limitations of Sustainable Plastics
While incorporating sustainable plastics is a worthwhile and sometimes necessary goal, the materials available for processing today do have limitations:
Capacity
Recycled plastic feedstock production increased more than four times between 2000 and 2020 but still accounts for only 6% of total plastics production, according to the Organization for Economic Co-operation and Development. One hurdle to increasing PCR volume is material collection.
“Current PCR plastic streams are not entirely efficient in separating materials,” Todd explained. “Even small amounts of contamination can destroy the value of a PCR product, and lot-to-lot variations in melt index, viscosity and density can result in a finished product that is inconsistent and inferior in physical properties to a comparable virgin resin.”
Some chemical and oil companies have pledged to increase supply and improve the consistency of recycled plastics through new chemical or advanced recycling plants. Companies focused on mechanical recycling plastic for feedstock are also emerging. Blue Polymers is one example of how organizations are investing in plastics recycling. The company’s advanced sorting process is designed to produce PCR with consistent quality from lot to lot. Until these dedicated recycling facilities are fully operational in the U.S.; however, capacity will continue to limit the amount of PCR on the market.
“There are a lot of challenges ahead, but emerging closed-loop recycling facilities should address many of the deficiencies of the current supply, including inconsistency, and make enough product to be economically competitive,” Todd said.
Applications
Though brand and consumer demand for sustainable materials is high, some applications may not be a good fit for recycled plastic or biopolymers. Rigid and flexible plastic products that do not require a letter of non-objection (LNO) from the U.S. Food and Drug Administration, such as industrial packaging, are the easiest to convert from virgin plastic to recycled plastic or biopolymers. Some coextruded products and less engineered injection molded parts can also be good applications to incorporate sustainable materials, according to Todd. Direct food-contact and medical applications, however, will require much more development before they can fully transition to sustainable materials.
Engineering Insights: Practical Plastics Solutions
M. Holland is committed to enabling a more sustainable future for plastics. Technical development engineers like Todd are available to provide expert guidance on the adoption of sustainable plastics and more. Explore M. Holland’s Sustainability group and line card to learn more and subscribe to receive the latest news and insights.
Disclaimer: The information provided in this post is intended solely for general guidance. Outcomes vary based on individual circumstances, and M. Holland Company, LLC does not ensure a specific result. Clients shall use their own independent skills and expertise when testing any application of technical support. M. Holland is not responsible and will not be liable for any discrepancies between expected and actual outcomes. M. HOLLAND DISCLAIMS ALL WARRANTIES, WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY OR FITNESS OF A PRODUCT FOR A PARTICULAR PURPOSE.
Todd has 27 years of plastics experience in technical service, applications development and market/business development. In his position with M. Holland, he reviews customers’ project requirements and makes technical recommendations based on his extensive knowledge of thermoplastic manufacturing processes. Todd holds a Bachelor of Science degree in Plastics Engineering from the University of Massachusetts at Lowell.