| 摘要 |
There is provided a face mask (10) having a mask portion that is extensible and retractable in at least one direction to improve the overall comfort and fit of the mask. The mask portion (22) may be a composite of several materials or layers (44, 46, 48, 50) joined by any conventional process, provided that the composite is extensible and retractable. At least one of the materials and/or layers (46) has properties of stretch and recovery that are imparted to the mask portion to render the mask portion extensible and retractable overall. |
