Photos courtesy of Dow
Last year, we were approached by the Ocean Conservancy, with whom we have a longstanding relationship, with a request—help us clean up the oceans in a more environmentally friendly way.
Each year, the Ocean Conservancy organizes and hosts the International Coastal Cleanup, through which volunteers collect marine debris from the world’s beaches. In 2017, the Ocean Conservancy wanted to take its efforts a step further by using bags made from recycled-content material for its trash collection. There were recycled-content bag options available on the market then—just like there are now—but we at Dow Packaging and Specialty Plastics decided to go one step further with this opportunity, in a way that we could only do successfully through collaboration with other industry groups.
As a longstanding supporter of the Ocean Conservancy for more than 30 years and member of its Trash Free Seas Alliance, we knew we had the right resources, technology and most importantly, likeminded groups to develop bags for the International Coastal Cleanup that would help difficult-to-recycle plastics enter the recycling stream.
We decided to take industrial scrap, otherwise destined for landfill, and extend its life by using the material to create the new trash bags. Together with flexible packaging manufacturer and FTA member Bemis Company, Inc., and Canada-based converter and bag manufacturer Polykar, Inc., we used a new Dow technology to reclaim previously non-recycled plastic barrier films, the type of packaging used in food packaging. Although the process of recycling plastic films isn’t new, the process of recycling these kinds of barrier films is.
A Strong Collaboration
No one company can tackle all of the different aspects of plastic recovery and recycling. To truly address the environmental challenges society faces, collaboration is essential. The public and private sectors must come together to find solutions for global issues like cleaning up marine debris.
Testing and using a new technology to manufacture 300,000 recycled-content trash bags for the Trash Free Seas Alliance would be no different. Once we determined we could use our RETAIN technology to overcome the challenges associated with recycling multilayered plastic films, while also tackling the marine debris issue, we reached out to likeminded industry leaders who could provide solutions to the remaining elements of the project—reclaiming the scrap and recycling it to manufacture the bags.
According to the Ocean Conservancy, by using the bags the organization distributed (and in some locations, locally supplied bags), International Coastal Cleanup volunteers removed more than 18 million pounds of trash from almost 15,000 miles of coast around the world during the September 2017 cleanup.
Dow turned to Bemis and Polykar to help bring the project to fruition. Both companies share our vision for the future, where valuable resources are reclaimed from goods after they are used, and then recycled or reused as many times as possible. And both companies have actively sought to address post-industrial waste challenges: Bemis uses its specialty packaging to extend the life of packaged food and reduce both food waste and excess packaging, and Polykar manufactures lines of compostable and recycled-content plastic bags.
To create the bags for this project, Bemis recovered the previously non-recycled barrier film plastic scrap and delivered that material to Polykar’s recycling facility. Polykar combined the reclaimed plastics with RETAIN in its recycling machines to create recycled plastic resin, and then used the reclaimed resins to manufacture the bags.
Realities of Plastic Recycling
As a flexible packaging manufacturer, Bemis produces a wide range of films. Some of those films can be recycled easily, while others present difficulties within normal recycling streams. Improving their sustainability performance is a major goal for Bemis, so the opportunity to reclaim more scrap and recycle was of great interest to company leaders.
To produce the bags and make the biggest positive impact possible, we chose to reclaim scrap barrier films—films designed with thin layers of a barrier polymer, in this case ethylene vinyl alcohol (EVOH)—meant to keep oxygen out, flavor and aroma in, and contents fresh. This added layer is essential to reducing food waste and ensuring the continued quality of the food it’s protecting, such as meat, cheese and nuts. These barrier polymers, and the “barrier films” into which they are made, are frequently used in consumer packaging, from the films on top of microwave dinners to the plastic bags that contain shredded cheese.
Consumers are familiar with the simple and established process of recycling standard, single-polymer plastic films. They’re accustomed to recycling milk jugs, water bottles and other solid plastic items by tossing them in a bin at home. Even polyethylene shopping bags and other polyethylene films, like case wrap from bottled water or paper towel overwrap, are recyclable by returning them to the bins at the front of most grocery stores. But post-industrial packaging with barrier polymers like EVOH are difficult to recycle because when different polymers are combined, the end result is a plastic mixture with poor physical properties or poor appearance. Films made from incompatible polymers might easily rip or break instead of stretching, and fail to produce consistent results.
Difficult-to-Recycle Plastic Material
The key to making the barrier films work for recycling is using a compatibilizer technology. The different polymer layers that make up barrier film require a chemical with a very specific composition, molecular weight and flow behavior to allow for the correct mixing during recycling. It seems simple enough to just add a compatibilizer to a mix of plastic, put it into the recycling machines and turn out plastic resins, because it is fairly easy to describe and understand. But the specific chemistry and physical characteristics involved with compatibilizing polyethylene and EVOH can be complex.
What makes a compatibilizer so essential is that without it, barrier film scraps cannot be recycled into a useful product. Without it, the recycled plastic wouldn’t have sufficient physical and optical properties for optimal performance, and it would be difficult to maintain the uniformity of the recycled plastic or the toughness of traditional polyethylene. For the ocean cleanup trash bags made with recycled content, RETAIN technology ensured the trash bags made from recycled products have the same puncture strength, tear resistance and impact strength as what you’d buy at a store.
Manufacturing the Bags
Polykar manufactures several lines of compostable and recycled-content trash bags for consumer and industrial use, and produced the ocean cleanup bags for this project. The company contributed its expertise in recycled plastic manufacturing to combine the precise amount of RETAIN and the scrap barrier films, and feed the proper mixture into its equipment, which produced the recycled material for the bags.
To truly address the environmental challenges that society faces, collaboration is essential.
The collaboration produced 300,000 recycled-content trash bags from post-industrial scrap and demonstrated the potential for a new technology to give millions of pounds of post-industrial barrier film scrap a second chance at life. Dow, Bemis and Polykar reclaimed films that wouldn’t typically be able to be recycled, and created bags without compromising performance, aesthetics and processing efficiency. The technology provides unprecedented opportunity to develop even more sustainable solutions for plastic packaging.
Sustainable Society
The collaboration between Dow, Bemis and Polykar was a success. The bags used in the coastal cleanup didn’t just make an impact by cleaning the world’s beaches; by using recycled plastic resins instead of new material, they also extended the lifecycle for barrier film scrap that was otherwise destined for a landfill and reduced the need to use virgin plastic to produce the bags.
According to the Ocean Conservancy, by using the bags the organization distributed (and in some locations, locally supplied bags), International Coastal Cleanup volunteers removed more than 18 million pounds of trash from almost 15,000 miles of coast around the world during the September 2017 cleanup. The newly created recycled-content bags performed as well as typical plastic bags when holding typical cleanup items, such as cigarette butts, plastic bottles and caps, food wrappers and takeaway containers. Although we didn’t have the foresight to manufacture a bag big enough for the piano one lucky volunteer discovered on the beach, this collaborative project was still a huge success.
About the Author: Jeff Wooster is the global sustainability director for Dow Packaging and Specialty Plastics. In this role, he collaborates with the entire value chain to promote and improve the sustainability value of plastic packaging. Jeff has more than 25 years of experience with Dow. Throughout his career, he has had various roles in different segments of the business including research, technical service and development, and marketing and sales. He has developed and implemented new technology for various application areas, such as stretch film, heavy duty shipping sacks and fresh-cut produce packaging. Jeff received a Bachelor’s of Science in chemical engineering from Iowa State University of Science and Technology, and lives in Houston, TX.