PADUA, Italy—The growing trend toward the use of silica in tires may be forced to slow due to shortages of the material, according to a top supplier. Unless tire companies better communicate their anticipated need for these reinforcing materials to their suppliers, the necessary investments will not be made in new capacity to keep pace with demand, said Martin Hess, European business manager for the carbon black and silica business of the newly formed Degussa-Huels A.G., speaking at a recent world carbon black conference in Padua.
The benefits of tread compounds with better rolling resistance, wet grip and abrasion resistance means silica is being used in tires for original equipment fitment, modern winter tires and all-season tires, Mr. Hess said.
``By 2005, 85 percent of car tires will contain silica,'' he said, adding that Degussa-Huels sees the silica ratio in some OEM green tires rising to 65 percent by rubber weight.
Truck tires use only a small amount of silica, 15 percent, and this is not predicted to rise because silica compounds show weakness in abrasion resistance. But there is a challenge for carbon black suppliers to reduce rolling resistance in truck tires, Mr. Hess said.
In addition to silica in passenger car tires, a further 8,000 tons a year go into truck tire treads to increase cut and tear resistance. The most conservative projection is that this will stay the same or rise to 10,000 tons annually. But if silica takes the same place in truck tire treads that it does in passenger cars, then a maximum of an extra 100,000 tons per year would be used in Europe alone, he said.
If North America and Japan develop in the same way as Europe, global demand for silica in tires could rise to 800,000 tons a year by 2005, Mr. Hess said.
However, there are two reasons why this isn't likely to happen.
One is that sufficient silica capacity simply does not exist. The other is that advanced fillers—anything that is not an ASTM carbon black—will be competing with silica for this market, he said.
Other reasons why silica use in green tires has not taken off in the U.S. include: U.S. driving conditions—bigger cars, long straight roads, lower speeds—and low gasoline prices mean less incentive to develop high-performance tires as do winter tires with low rolling resistance and good wet/ice grip.
Run-flat tires also are an important development. ``I have every confidence that in 10 years time from now, we will not see spare tires in new cars,'' Mr. Hess said.
Another speaker, Robert Goldberg of New Vernon Associates, indicated that successful commercialization of run-flat tires—and hence complete elimination of the need for spare tires—could reduce carbon black demand by 6 to 7 percent, a ``worst-case scenario.''
But Mr. Goldberg also pointed out that run-flats contain more carbon black and wear faster than standard tires, so that four run-flats may contain more carbon black than four conventional tires and a spare tire.