| 摘要 |
PURPOSE: To obtain a non-contaminating fluorocarbon fiber filter which is substantially permanently whitened. CONSTITUTION: This process for reducing the level of extractables, whitening, and rendering a porous material non-contaminating, where the porous material is comprised of bonded fluorocarbon fibers and a fluorocarbon chemical binder. The thermal bleaching process includes exposing the material for at least several hours to a vigorously agitated oxygen-containing atmosphere maintained at a temperature of at least about 204 deg.C. |
