Binder eliminates itch from fiberglass liners

Littleton, CO--Fiberglass liners offer a wide variety of advantages for vehicles. They can reduce transmission of engine noise, improve cabin acoustics, and enhance thermal performance. Unfortunately, fiberglass liners can also cause itch and skin irritation for assembly line workers.

Now, however, engineers at Schuller International, Inc., have created a fiberglass liner material that solves thatproblem. Known as AroLite(R) DX, it reduces and, in many cases, eliminates, skin irritation.

Key to the new liner material is the development of a specially designed binder that enhances elasticity of the glass fibers without damaging acoustical or thermal properties. To apply the binder, the manufacturer places the fibers, which measure 5 to 7 microns in diameter, in a high-velocity air stream, then it sprays the binder onto the fibers.

Like other conventional fiberglass liners, AroLite DX employs a phenol formaldehyde-based binder. But the new binder departs from the conventional in its use of a proprietary latex additive, which coats the glass fibers. During use, the latex coating provides the fibers with greater elasticity, thus allowing them to bend more readily. This elasticity results in less shattering of the fiberglass, which, in turn, results in less skin irritation.

Schuller engineers say that the latex additive also reduces skin irritation in another way: It emits less dust. In tests, they found that binder dust causes as much skin irritation as shattered fibers. "That was an eye opener for us," notes Joseph Rumiesz, a business development manager for Schuller. "We had always assumed that glass was the sole cause of itch and skin irritation. But by modifying the binder we cut down on dust, and learned we could reduce skin irritation."

One of the keys to the material's success is the fact that it reduces the skin irritation problem without altering the material's acoustical or thermal performance. Schuller engineers say that the latex mixed well with the other binder components and, as a result, it did not necessitate an increase in the amount of binder material. If it had, the extra binder could have reduced the performance benefits of the fiberglass liner. "If you add too much binder, you close off the air spaces in the product and it affects acoustic and thermal behavior," Rumiesz explains.

Schuller engineers tried more than a hundred different additives during a four-year period before settling on the latex. Many, Rumiesz says, could not stand up to the heat applied during the AroLite DX curing process. Engineers also took pains to find an additive compatible with phenol formaldehyde. Phenol formaldehyde has been used for several years as an alternative to high-TMA (trimethylamine) products, which emit an undesirable odor when subjected to high humidity or moisture.

AroLite DX's combination of characteristics is expected to appeal to engineeers working on a wide array of applications. Those include cabin and underhood applications in automotive and off-road vehicles. "It isn't so much what the latex additive does, as what it doesn't do," says Edward G. Livesay, Schuller business manager for OEM automotive. "It solves the itch and irritation problem without compromising material performance."

Additional details...Contact Edward G. Livesay, Schuller International, Inc., 10100 W. Ute Ave. (80127), P.O. Box 625005, Littleton, CO 80162, (303) 978-3147.