AKRON-The University of Akron and National Feedscrew, a Massillon, Ohio, manufacturer of extrusion equipment and tire presses, have developed a process of devulcanizing scrap tires through the use of ultrasonic sound waves. ``It's very exciting technology, and it does work,'' said Paul Roberson, vice president of product development for National Feedscrew.
The technology involves blasting 10- to 16-mesh scrap tire crumbs with ultrasonic waves to break the chemical bonds that form during the curing process.
Professor Avraam I. Isayev, director of the University of Akron's Molding Technology Center, called the technology ``impressive.''
``We started with two pounds an hour, three years ago. Now, we can make 100 pounds an hour,'' said Mr. Isayev, who is heading the research.
National Feedscrew is now building equipment that would accommodate about 300 pounds an hour, according to Mr. Isayev.
The patented process, which uses no chemicals, subjects scrap tire crumbs to elevated temperatures and pressures and pounds them with a dose of ultrasonic waves. The waves break the carbon-sulfur and sulfur-sulfur bonds in a matter of milliseconds, according to Mr. Isayev.
The process can be used to recycle many different rubber compounds, including those with silicon, although the research is focused on scrap tires, Mr. Isayev said. The amount of heat, pressure and ultrasonic waves applied to the rubber can be very different, depending on the structure of the compound, he said.
It would be feasible to make the process commercially available within a year, Mr. Roberson said.
``I think we are ready to go into (business) development now,'' added Mr. Isayev. ``One can do research and at the same time go into business development.
``It will be cost-effective because as we scale up, the cost will go down. We started, maybe, at $6 a pound, and we may be able to get down to 20 cents (per pound).''
However, Michael Blumenthal, executive director of the Scrap Tire Management Council, believes the recycled material may have restricted applications and may not be able to be used in tires and belts.
``I have serious doubts that the end product has any valued use,'' he said.
But Mr. Roberson contends the University of Akron scientists have proven the process to be commercially usable.
``You can put this material back into products for use in some critical applications,'' said Mr. Isayev. ``We have seen that already.''
The recycled rubber would have to be mixed with natural rubber to make a new tire. ``But you have to develop the technology to the level where you are comfortable doing that,'' he said.
``In the meantime, there are a lot of interesting uses, such as gaskets or mud flaps,'' said Mr. Isayev, noting that companies already have sent material to him to be devulcanized.
``They send their garbage and try to find out if they can incorporate it into their product. Some of them are very happy with the initial results; others want us to do more experiments,'' he said.
National Feedscrew, which builds the equipment for the process, owns the exclusive license for both the equipment and the process, and plans to sell the recycled material, according to Mr. Roberson. ``We feel this is the one that's going to be outlasting everyone else's technology.''