WASHINGTON-Two renowned rubber scientists-one Malaysian, one Russian-have jointly invented a rubber recycling process they claim devulcanizes rubber to the point where it regains 75 percent of its virgin properties. One of them, B.C. Sekhar, has founded STI Corp. Sdn. Bhd., based in Malaysia, to market the patented ``De-Link'' recycling process and ``DeVulc'' recycled rubber.
STI's U.S. subsidiary, STI-K Polymers America Inc., signed an agreement Feb. 2 with Baker Rubber Co., a major crumb rubber producer, to form a joint venture to produce DeVulc.
That operation will use existing space in Baker Rubber's South Bend, Ind., plant, but will require some additional STI-K equipment.
By April 1, STI also plans to open a plant in Malaysia that will produce 1,000 tons of the De-Link chemical reactant-enough to devulcanize 20,000 tons of rubber- each month.
The De-Link reactant is made of chemicals already in common use throughout the rubber industry, according to Mr. Sekhar. ``The chemistry was there all the time, staring us in the face,'' he said in a telephone interview from Kuala Lum-pur, Malaysia.
Mr. Sekhar, former chairman of the Malaysian Rubber Research and Development Board, said the development of the De-Link process was an outgrowth of his 30-year association with Vitaly Kormer, chairman of the Synthetic Rubber Producers Association in Russia, who also helped develop an early devulcanization process.
``The Russian method was effective, but the chemicals were toxic and degraded the rubber,'' Mr. Sekhar said. ``The question was how best to devulcanize rubber without anything toxic.''
In the process Messrs. Sekhar and Kormer developed, De-Link reactant is added to crumb rubber at ambient temperatures on a conventional open mill. The resulting DeVulc can be used either on its own or compounded with a wide range of natural and synthetic rubbers, and revulcanized using conventional methods.
``We're shifting the process backwards from vulcanization to a virtually devulcanized product,'' said Kok-Kee Hon, vice president of technical services and marketing for STI-K Polymers America, based in Washington. ``The product is not wholly devulcanized, because you can't cut every link. But there's an enormous difference between traditional reclaim and our DeVulc.''
Although STI executives see applications for DeVulc in various blends throughout rubber product manufacturing, the most immediate market for the product will be in industrial molded and extruded goods, according to Frederic W. Siesseger, president of STI-K Polymers America.
``We estimate there's a market of at least 500,000 tons in the U.S. that's immediately available for DeVulc,'' he said. Flooring, hoses, belts and molded goods are among the product lines STI can move into quickly, he added.
The company also hopes to supply the tire market eventually, but it will take some effort to overcome the ingrained prejudice in that industry against reclaimed rubber, Mr. Siesseger said.
``People have been led to believe that devulcanization can't be done,'' he said. ``Our biggest market obstacle will be to show people that it can.''
Tests performed in England indicate that tire compounds can contain up to 40 percent DeVulc without loss of virgin properties, according to Mr. Siesseger. This compares with the 1 percent or less of traditional reclaim that can be used before quality suffers.
Rubber product makers can expect to lower their costs significantly by using DeVulc-particularly important, Mr. Siesseger noted, in an industry where markets are mature, profit margins low and the cost of virgin materials is skyrocketing. ``We can really help them improve their profit margins,'' he said.