Inner shell and mask including same

1. An inner shell, which is provided to maintain a shape of a mask and formed in a cup shape, the inner shell comprising:

a circumferential part forming an edge;

a curved part formed in an arch shape from an inner side of the circumferential part; and

a plurality of ribs formed to radially protrude from a peak area of the curved part toward the circumferential part,

wherein the circumferential part, the curved part, and the ribs are integrally formed as a sheet member formed of a porous material, and wherein one end of each of the plurality of ribs is formed to come into contact with ends of the other ribs at an inner portion of the peak area.

2. The inner shell of claim 1 , wherein the plurality of ribs are formed such that the ribs formed at a left side and the ribs formed at a right side are symmetrical with respect to a vertical central line of the inner shell.

3. The inner shell of claim 1 , wherein the plurality of ribs are formed such that the ribs formed at an upper side and the ribs formed at a lower side are symmetrical with respect to a horizontal central line of the inner shell.

4. The inner shell of claim 1 , wherein the circumferential part, the curved part, and the ribs are formed by hot-pressing the sheet member.

5. The inner shell of claim 1 , wherein:

concave parts are formed between the plurality of ribs; and

the concave parts are provided such that a width thereof progressively increases toward the circumferential part.

6. The inner shell of claim 1 , wherein the sheet member comprises a non-woven fabric.

7. The inner shell of claim 6 , wherein the non-woven fabric is formed of polyester short fibers.

8. The inner shell of claim 1 , wherein a thickness of each rib is in a range of 0.5 mm to 1.5 mm.

9. A mask comprising:

an inner shell of claim 1 ; and

a filter structure coupled to an outer surface of the inner shell.

10. The mask of claim 9 , further comprising a strap coupled to the filter structure.

11. The mask of claim 9 , wherein a circumferential part of the filter structure is coupled to the circumferential part of the inner shell.

12. The mask of claim 11 , wherein the circumferential part of the filter structure is heat welded or ultrasonically welded to the circumferential part of the inner shell.

13. The mask of claim 9 , wherein the filter structure comprises a filter layer and a cover web coupled to an outer surface of the filter layer.

14. The mask of claim 13 , wherein the cover web is further disposed on an inner surface of the filter layer.

15. The mask of claim 9 , further comprising a face adhesion part coupled to the circumferential part of the inner shell, wherein the face adhesion part is adapted to adhere to a user's face.

16. The mask of claim 9 , wherein the plurality of ribs of the inner shell are formed such that the ribs formed at a left side and the ribs formed at a right side are symmetrical with respect to a vertical central line of the inner shell.

17. The mask of claim 9 , wherein the plurality of ribs of the inner shell are formed such that the ribs formed at an upper side and the ribs formed at a lower side are symmetrical with respect to a horizontal central line of the inner shell.

18. The mask of claim 9 , wherein the circumferential part, the curved part, and the ribs of the inner shell are formed by hot-pressing the sheet member.

19. The mask of claim 9 , wherein:

concave parts are formed between the plurality of ribs of the inner shell; and

the concave parts are provided such that a width thereof progressively increases toward the circumferential part of the inner shell.

20. The mask of claim 9 , wherein the sheet member of the inner shell comprises a non-woven fabric.