Patent ID: 11877609
Assignee: EVIT GLOBAL CO., LTD.
Field: Chemical engineering (Chemistry)
Classification: CPC A  B  C | IPC A  C

Claim 4:
5. A mask sheet used for a face mask; the mask sheet comprising:
a first layer grouping located on a side of the mask sheet proximate a wearer's face, the first layer grouping comprising at least a first layer having a central portion and an edge portion, and a second layer having a central portion and an edge portion;
an ePTFE membrane having a central portion and an edge portion; and
a second layer grouping located on a side of the mask sheet opposite a wearer's face, the second layer grouping comprising at least a third layer having a central portion and an edge portion, and a fourth layer having a central portion and an edge portion;
wherein:
the ePTFE membrane is disposed between the first layer grouping and the second layer grouping;
the edge portions of the first layer, the second layer, the ePTFE membrane, the third layer, and the fourth layer are mutually bonded; and
the first layer, the second layer, the third layer, and the fourth layer are each independently formed from a material selected from the group consisting of: polypropylene (PP) and polyethylene terephthalate (PET).