Recycled plastic bags and wraps are often made into new bags or plastic lumber, but preliminary research by the Plastics Industry Association shows there could be "further opportunities to extract value from these streams" of mixed polyethylene films.
The trade association has completed the first phase of what's being called the New End Markets Opportunities (NEMO) Project for Film.
Plastic bags collected at retail locations are typically made from high and low density PE, with some level of contamination, explained Kim Holmes, the association's vice president of sustainability.
That material is usually made into either new bags or plastic lumber.
But a goal of the project is to determine ways to strip out processing costs and find new end markets, Holmes said.
The effort comes as the American Chemistry Council, the U.S. Environmental Protection Agency and the Sustainable Packaging Coalition have been working together to double the collection and recycling of PE film to 2 billion pounds by 2020.
"I have no doubt they will they will succeed. It's a fantastic program. It became very apparent that in order for that to be successful, we needed to explore new end markets," Holmes said.
So NEMO for Film has gathered representatives from about 45 companies to consider new ways to handle recycled film.
"We knew that in order for this to be successful, we had to look at the most cost-efficient processing of this material," Holmes said.
Researchers decided to process recyclables that were sorted only for non-plastic contaminants and make pellets directly from that material. Skipping optical sorting, washing, drying, extrusion and filtration lowered costs.
"We've tested a number of different samples under different processing conditions. We've been very surprised by the quality of the material. It's quite functional material," Holmes said.
The medium density PE contains small amounts of other plastics.
"What you get in the blend is a mid-density profile. ... That said, there is some multilayer material that is inadvertently put in there. We wanted a real-world snapshot of what this material would look like without extensive processing," Holmes said.
Researchers are studying appropriate end markets for the material, including agricultural, building and construction, industrial film and rotational molding applications.
"This process has really helped accelerate analysis of materials for potential end users," she said.
A second phase, currently underway, wants to replicate the findings of the initial work. A third phase will be a hard push to develop additional end markets.
Another surprising potential market could be use as a binder in asphalt, Holmes said. Reclaimed plastic has been used as such in other countries, but not in the United States. Preliminary analysis shows the addition of PE to asphalt improves the temperature failure rate. "It actually could have some value-added properties," Holmes said.
