This article originally appeared in the November 2018 issue of Resource Recycling. Subscribe today for access to all print content.
Vehicles destined for recycling today incorporate more plastic than scrapped cars of yesteryear, but almost none of the plastic is being recycled in the U.S.
Scrap workers pull off valuable auto parts for reuse, and magnets separate metals from shredded vehicles. But plastics typically take a ride straight to the landfill.
“Right now, virtually none of it is being collected,” said Kim Holmes of the Plastics Industry Association. “Really, auto recovery is being driven by the metals, not the plastics.”
A project spearheaded by her group is intended to help alter the equation by targeting bumpers from end-of-life autos.
Holmes, Sanjay Dutta of Geo-Tech Polymers and David Wagger of the Institute of Scrap Recycling Industries (ISRI) spoke about the ongoing auto plastics project during the Plastics Recycling Conference in earlier this year in Nashville, Tenn.
The focus was on the End-Of-Life Vehicle Recycling Project, which concluded its first phase in November 2017. On Feb. 20, the Plastics Industry Association released a project report detailing the initial outcomes of the effort.
‘Picking’ a feedstock
A lot of automotive components are plastic, but identifying the best parts to target – and the best methods for collecting them – took research.
Holmes, vice president of sustainability at the Plastics Industry Association, noted that manufacturers are increasingly using plastics in vehicles, both to achieve design freedoms and to reduce vehicle weights to meet higher fuel-efficiency standards. Today’s typical car uses about 250 pounds of plastic – “high-value, high-performance plastics,” Holmes specified.
Wagger, chief scientist and director of environmental management for ISRI, said he ran numbers for 1995 and 2014 model-year vehicles. Over that span, plastics and polymer composites went from making up about 6.5 percent of the typical vehicle weight to 8.2 percent. In all, he estimates about 1 million to 2 million metric tons of auto plastics that could theoretically be recycled are disposed of each year in the U.S.
In searching for points at which to collect plastics from end-of-life vehicles, two opportunities present themselves: pick the intact parts off a vehicle sitting in a yard, or sort the plastics from auto shredder residue (ASR), which is a mix of fluff leftover after the vehicles have been shredded and the valuable metals extracted.
“Some of that [ASR] recovery is happening in Europe, but no one here in the U.S. has the capability to be sorting that material, so that would be a very big barrier to overcome to get a good project going,” Holmes said. “So we thought, ‘Well, what about whole parts?’”
Wagger noted the benefit of this approach is it avoids damage to the polymers caused by powerful auto shredders as well as yield losses, separation challenges and regulatory issues. “Now you have really high-quality material that’s effectively very clean that can be further processed,” he said.
But the stakeholders bumped into a big question: Which parts to target? Just considering the exterior of vehicles, many plastic components emerge as possibilities: hood and trunk lids, light covers, mirror cases, fenders, doors, bumpers, grills and others.
To help determine a direction forward, the Plastics Industry Association employed the help of its Transportation and Industrial Plastics (TIP) group, which is made up of representatives of automakers, resin suppliers, recycling companies and more. The TIP group went through the exercise of identifying every plastic component on a vehicle before it began narrowing the list.
Using two criteria, large size and little variability, they landed on bumpers. The average vehicle has about 20 pounds of bumper plastic on it, and it’s a homogenous source, mostly made up of thermoplastic polyolefins (TPO), Holmes said. (Some older vehicles use urethane bumpers, but they’re visibly very different from TPO ones, she noted.) TPO bumpers are made of modified polypropylenes with expensive rubber packages, which give them special impact and durability qualities.
Wagger noted that bumpers were also an attractive choice because they’re on the outside of the vehicle, making them possible to remove even if a vehicle has been flattened. He estimates about 100,000 metric tons of TPO bumpers are sent to scrap yards in the U.S. each year.
Picking bumpers isn’t without its challenges, however.
Removing them is labor intensive, Wagger noted, and there are important downstream logistical considerations. He also noted that removing a bumper is new for an industry used to shredding vehicles. “It’s very … out of normal business practice to try to pull off a bumper,” he said.
The Plastics Industry Association partnered with the Auto Recyclers of America (ARA), which represents auto salvage yards. The Plastics Industry Association created an economic pro forma spreadsheet, allowing salvage yards to plug in the number of vehicles processed annually, average labor costs, number of bumpers pulled per hour, estimated price per pound paid by plastic reclaimers, transportation costs, and methods of preparation (loose, baled or shredded) to determine whether pulling bumpers might be a financial winner or loser for them.
The biggest variable is likely to be transportation, Holmes said. The key to success in that realm will be getting sufficient densities to make transportation to the reclaimer cost effective.
For the project, ARA identified an auto salvage yard in Binghamton, N.Y. as a candidate to test bumper recovery, according to the Plastics Industry Association’s report recapping the project. That company, Gary’s U-Pull It, hosted a project kick-off event and tour in July 2016.
Within a few months, staff at Gary’s U-Pull It recovered about 4,500 pounds of bumpers, which were baled and delivered to Geo-Tech Polymers in fall 2016.
Processing the plastic
Geo-Tech is a Waverly, Ohio-based reclaimer that provides a variety of services and handles multiple resins, including TPO. Among the technologies it employs is a patented process for removing coatings and inks on plastic items.
The TPO bumpers Geo-Tech received as part of the project were split into two batches: those undergoing paint removal before pelletization and those shredded and left with the paint intact.
The company already had experience recycling post-industrial TPO bumper scrap. Dutta, CEO of the company, said the key step in the post-consumer bumper project was the preparation of material, including remo val of metal clips, nylon and other contamination. If those tasks are done correctly, the company can return the TPO to a near-virgin state, he said.
Geo-Tech experienced “growing pains” with the project, including difficulties in unloading un-baled bumpers from a semi-truck trailer at the processing facility. “We had a truck show up with loose TPO bumpers, so we were literally carrying one bumper out at a time,” Dutta said. “And it was not in the same shape. … Some of it was crushed. Some of them were just literally yanked out and came in different shapes.” The unloading alone took his staff four hours; it should have taken five minutes, he said.
When loads came in baled, it was more manageable unloading and sending bumpers into the shredding process, he said.
After pelletizing the TPO, Geo-Tech performed preliminary testing of the plastic’s properties. It found the plastic “had desirable physical properties, including high strength, low moisture and high resistance,” according to the project report.
Geo-Tech also compared the result of the post-consumer TPO with that of post-industrial TPO it processes. The results were similar. For example, ash content for the post-consumer plastic was 20 percent, compared to 19 percent for post-industrial bumper plastic. With regard to the melt flow index, the post-consumer plastic measured 15 grams per 10 minutes, compared to 16 grams per 10 minutes with post-industrial plastic.
‘Plastic ninja’ jumps in
Next, the TPO was further analyzed by Midland Compounding and Consulting (MCC) of Midland, Mich. Described by Holmes as a “plastic ninja,” MCC has facilities to research recycled resin uses in various applications. The company sells into the automotive, defense, industrial materials, office furniture, packaging, sporting goods and textiles sectors.
For this project, MCC compounded and tested a number of different TPO bumper streams, including pellet from Geo-Tech’s process. MCC injection-molded the plastic and tested its physical, mechanical and rheological properties, comparing the results with BMW specifications. Based on the study, MCC saw good potential for the Geo-Tech sample.
MCC then compared the Geo-Tech sample with a different batch of post-consumer TPO bumper plastic provided by Ajax, Ontario reclaimer Post Plastics. The Post Plastics sample, which consisted of shredded plastic with the paint left intact, showed higher strength and impact resistance than the Geo-Tech batch. “A primary contributing factor to the differences in mechanical properties could be due to the additional heat history of the pelletized Geo-Tech material,” according to the project report.
But the Post Plastics batch would be limited by its visual characteristics. MCC molded both samples into plaques. The plaque from Post Plastics’ shredded, painted plastic had an uneven surface appearance, limiting it to non-visible utility applications, the project report concludes.
When the Plastics Industry Association staff got the first preview of the properties of the Geo-Tech plastics, they were “pretty astounded,” Holmes said. Companies are already out there recycling post-industrial TPO bumpers, so there’s a good understanding about how that material performs. The quality of the post-consumer material processed by Geo-Tech nearly matched that post-industrial quality.
“We thought to ourselves, ‘How is that possible?’ I mean, these bumpers have been in use for at least a decade, exposed to sun, salt, solvents,” Holmes said. “And the only thing we can surmise is the paint does such a good job protecting the polymer.”
The testing continues. Spartanburg, S.C.-based Milliken and Co. expressed interest in mixing its additives with the TPO bumper plastics. Earlier this year, the company supplied three Deltamax modifier additives and began analyzing how they affected melt flow and izod impact ratings. Initial results, which showed clear shifts in the plastic’s properties, were presented at the Plastics Recycling Conference.
Finding a home
The properties of the post-consumer TPO pellet made that plastic good enough to go into at least one auto application.
MCC was asked by an automaker to provide a sample of recycled TPO for a secondary mud flap for a small-volume vehicle. It submitted the paint-stripped TPO pellets from Geo-Tech. The plastic was molded in February 2017 and given initial approval by an injection molding company that produces parts for vehicles.
“They are pleased enough with the cost savings and the performance of the material that they’re looking for other opportunities on the vehicle,” Holmes said.
Potential applications for the recycled TPO material are wide, because they meet or exceed standards for a number of applications. Additionally, because they already contain the valuable rubber package – a significant cost for makers of virgin TPO – they can be priced competitively to prime plastics, Holmes noted.
Based on his research, Dutta said he sees potential uses for the recycled TPO in a number of industries: consumer products, transportation, construction, decorative products and seasonal items.
Toyota, a member of the Plastic Industry Association’s TIP group, also tested the recycled TPO bumper plastic. A sample of Geo-Tech’s pellets was shipped to Toyota Motor North America’s large research-and-development center in Ann Arbor, Mich. There, the plastic was molded and tested, and the results were compared with the company’s TPO parts specifications. Ultimately, the samples failed, falling short in a couple of measures of strength. But according to the project report, Toyota team members still saw potential for its use in non-automotive applications.
And that’s where a different effort showed success. West Des Moines, Iowa-molding company i2Tech created pallets from the recycled TPO plastics. Looking for an alternative feedstock to create pallets for a customer, i2Tech processed two samples provided by Geo-Tech: paint-removed pellets and shredded plastic with paint.
“Both TPO samples processed much better than the material currently being used for this customer,” the project report states.
The pellets performed without issue. Using them, i2Tech made both one-time-use pallets and more-robust racking pallets. But the shredded TPO was less consistent and presented processing challenges, including smoking and liquid oozing.
Additional applications may be on the way. Holmes said the recycled TPO is being considered for large-volume uses in ATVs and UTVs (utility task vehicles). A manufacturer is currently looking at a potential direct drop-in replacement for virgin plastic, Holmes said.
“We could be talking about a million pounds a month of demand,” she said. “None of this would be made possible if we didn’t have the physical data and the pellets ready to go and put in their hands. So we are accelerating their evaluation of the material and the opportunities.”
heading into next phase
The Plastics Industry Association is well into the second phase of the project. Earlier this year, two of ISRI’s auto-recycling members sent three shipments of bumpers to reclaimers Geo-Tech, ACI and Ultra-Poly for processing. The bales were prepared in accordance with ISRI’s “Post Consumer TPO Plastic Automotive Bumper Covers” specification, which was released in mid-2016. Holmes said test results are coming back for those batches. Details on them will be included in a phase two report to be released soon.
As part of its future work on the project, the Plastics Industry Association plans to dive deeper into potential end markets, leveraging the power of the group’s own members and their supply chain networks. The hope is to make the bumper project a stepping stone into recovery of other auto plastics, she said. That was a point Wagger also emphasized.
“I think an important part of this opportunity is it could demonstrate the feasibility of recycling other automotive plastics,” he said. “It could bootstrap those other recycling opportunities.”
Jared Paben is associate editor of Resource Recycling and can be contacted at [email protected].