US tire group "optimistic" over search for 6PPD alternatives

Washington – The US Tire Manufacturers Association (USTMA) believes global collaborations will identify alternatives to 6PPD anti-degradants used to protect tire-rubber materials.

In a hearing at the US Senate environment and public works committee on 31 July, USTMA reported on joint efforts among 30 global tire makers to replace the anti-ozonant - identifed as a hazard to certain aquatic life.

The programme has completed analysis work on seven prospective alternatives identified from 60 substances, according to the association.

“We are optimistic that we will have identified one or more possible alternatives that hold promise to replace or materially reduce 6PPD in motor vehicle tires,” said USTMA.

However, this assessment is subject to future performance testing to ensure comparable tire safety and performance, the industry body emphasised.

According to USTMA, additional toxicity testing may need to be performed to satisfy regulatory requirements and to fill important data gaps.

In addition to the efforts conducted by the consortium, USTMA highlighted other projects with local authorities and chemicals suppliers to find 6PPD alternatives.

6PPD, it noted, is “exceptional” in ensuring tire and passenger safety and has been used for decades: protecting the components of the tire from attack by ozone and oxygen.

However, over the recent years, some researches have raised concerns over a 6PPD transformation product, 6PPD-quinone (6PPDQ), which can impact aquatic life, particularly salmon.

USTMA added that it was adopting a wholistic approach towards addressing the issue, noting that "finding and implementing alternatives to 6PPD, while still complying with safety standards, will take time."

In the meantime, continued the submission, there are "things that can be done now to reduce 6PPD and 6PPDQ in the environment.” 

These measures, it said, include: street-sweeping in urban areas; using rubber-modified asphalt and permeable pavement surfaces that reduce tire abrasion; maintaining appropriate tire inflation; and mitigating stormwater impacts.