| 摘要 |
Herein are disclosed face masks that are provided in a generally flat configuration and are capable of being expanded to a cup-shaped configuration. Such masks comprise at least one porous layer that comprises at least one pleat and that is capable of being expanded by at least partially unfolding the at least one pleat. The mask further comprises at least one stiffening element that comprises at least one engaging feature. Upon expanding the porous layer, the engaging feature engages with the porous layer so as to enhance the ability of the mask to maintain the expanded, cup-shaped configuration. |
