A PET industry program to develop new uses for hard-to-recycle bottles has found its largest potential application to date in an unlikely place - the bottom of a coal mine.
The National Association for PET Container Resources in Charlotte, N.C., said the mining industry has developed technology to use uncleaned recycled PET as an adhesive to support steel rods that hold up mine shafts.
The application came about as part of work done by NAPCOR's Top Bottle project.
Jennmar Corp. of Pittsburgh, one of the largest makers of roof-support systems for mines, plans to retrofit five of its plants to use the technology, according to Mike Schedler, NAPCOR vice president of technology.
Jennmar did not respond to an interview request, but Schedler said the technology uses injection molding equipment to make PET coverings for parts of the steel rods.
When the steel rods are vibrated in the mine shaft, the PET-based coverings help adhere the rods to the rock walls, he said.
Schedler said the company did not want to talk in detail about the process, which has been tested by the Mine Safety and Health Administration. The technology was developed by Terrasimco Inc. in Martinsburg, W.Va., and licensed to Jennmar.
The application is potentially significant for the PET recycling industry, Schedler said, because it uses dirty packaging that does not have to be cleaned. The technology can work with any mix of PET bottles, he said, and produces a stronger adhesion when caps and labels made from polyolefins are left in the stew.
``There isn't any mixture of post-consumer ground bottles that hasn't been successful,'' he said.
But it remains to be seen whether it will produce significant volumes.
NAPCOR said Jennmar could use about 15 million pounds of PET by the end of 2005. Schedler called that a conservative figure because it is only a small portion of the existing market for mine-support rods.
NAPCOR's Top Bottle project is designed to find new uses for PET bottles, for things like juices and alcohol, that have barrier layers or unusual colors, and that have proved challenging to some recyclers. The materials cost recyclers money to remove, but they don't often have markets for it.
The Top Bottle project has found markets for about 40 million pounds in new uses thus far, including the potential 15 million from Jennmar, he said. This is the first application NAPCOR has been able to talk about, he said.
The project has found applications for an additional 20 million to 30 million pounds of material each year in existing products that have switched to using the motley mix of barriers and colors Top Bottle focuses on, he said.