| 摘要 |
Improved filtration medium comprises at least two individual, separate and distinct layers of melt blown fibers, the layers being arranged in face-to-face contact. The two-layered filtration medium has better particulate filtration efficiency (for particles 0.8 micron in diameter and larger) than that provided by a single layer of the same melt blown fibers having a basis weight equivalent to the combined basis weight of the two individual layers. The improved filtration medium is useful in the manufacture of face masks, especially face masks for medical or surgical use. |
