Composite sheet and absorbent article using the composite sheet

1. A composite sheet, comprising:

a film sheet having a plurality of openings and/or a plurality of slits; and

a fiber aggregate layered on a first side of the film sheet,

wherein

the fiber aggregate includes a plurality of projecting regions that project to a second side of the film sheet opposite to the first side, through the plurality of openings and/or the plurality of slits, each of the projecting regions including a base portion,

the film sheet includes a groove disposed between a pair of adjacent projecting regions among the plurality of projecting regions and having

a bottom

two branches both extending from the bottom in a projecting direction of the projecting regions and covering at least a portion of the base portion of one of the adjacent projecting regions, and the projecting regions are disposed in a staggered manner.

2. The composite sheet according to claim 1 , wherein the groove extends in a straight line or in a curved line in a predetermined direction.

3. The composite sheet according to claim 2 , wherein

the film sheet comprises two grooves extending side by side in the predetermined direction and between said two adjacent projecting regions, and

each of the grooves extends in the curved line in the predetermined direction.

4. The composite sheet according to claim 1 , further comprising another fiber aggregate including cellulosic fiber and disposed on said fiber aggregate, said film sheet being arranged between said fiber aggregates.

5. An absorbent article, comprising:

a top sheet that is at least partially liquid permeable, and includes the composite sheet according to claim 1 in at least a portion thereof;

a back sheet that is liquid impermeable; and

an absorbent core, which is liquid retentive, disposed between the top sheet and the back sheet,

wherein the plurality of projecting regions faces toward the absorbent core.

6. An absorbent article of an elongated shape, comprising:

a top sheet that is at least partially liquid permeable;

a back sheet that is liquid impermeable;

an absorbent core, which is liquid retentive, disposed between the top sheet and the back sheet; and

a second sheet that is at least partially liquid permeable and disposed between the top sheet and the absorbent core, and includes the composite sheet according to claim 1 in at least a portion thereof,

wherein

the plurality of projecting regions faces toward the absorbent core.

7. The absorbent article according to claim 6 , wherein

the fiber aggregate of the composite sheet has a first portion in direct contact with the groove and a second portion free of direct contact with the groove, and

the first portion of the fiber aggregate is in direct contact with a lower side of the top sheet.

8. The composite sheet according to claim 1 , wherein each of the projecting regions includes a communicating hole on an apex or on a side face thereof.

9. The composite sheet according to claim 1 , wherein a distance between said two adjacent projecting regions in a first direction is from −5 to 10 mm, and

a negative value of the distance indicates that the adjacent projecting regions overlap each other without a gap when viewed from a second direction orthogonal to the first direction.

10. The composite sheet according to claim 1 , wherein the groove continuously extends in a predetermined direction and along the plurality of projecting regions arranged in the predetermined direction.

11. The composite sheet according to claim 1 , wherein two grooves are arranged between said pair of adjacent projecting regions.

12. The composite sheet according to claim 11 , wherein said two grooves between said two adjacent projecting regions are separated from each other and are not formed in one piece.

13. A method of manufacturing a composite sheet, said method comprising:

disposing a substantially fiber aggregate on a first side of a film sheet to define a composite sheet; and

pushing the composite sheet by a predetermined projecting region forming device from the first side of the film sheet toward a second side of the film sheet, said second side being opposite to the first side, to form a plurality of projecting regions projecting from the second side of the film sheet

wherein the predetermined projecting region forming device includes

a first member having a plurality of openings that are disposed in a staggered manner; and

a second member having a plurality of projections that correspond to the plurality of openings and are disposed in the staggered manner to form the projecting regions arranged in the staggered manner.

14. The method according to claim 13 , wherein,

the first member has a flat surface or a curved surface with the plurality of openings, and

the second member has a flat surface or a curved surface with the plurality of projections

the flat surface or the curved surface of the second member faces toward the flat surface or the curved surface of the first member, and

the film sheet faces toward the first member and the fiber aggregate faces toward the second member,

the composite sheet is tucked between the first member and the second member such that at least one of the plurality of projections of the second member engages with at least one of the plurality of openings of the first member, so as to form the plurality of projecting regions.

15. The method according to claim 14 , wherein a draw ratio caused by the projections is higher than an elasticity of the film sheet in a direction between the first side and the second side.

16. The method according to claim 13 , wherein the film sheet is a low-elasticity film sheet.

17. A method of manufacturing an absorbent article, comprising

providing a sheet which has a portion that includes the composite sheet manufactured according to the method of claim 13 , and

providing an absorbent core below the composite sheet in a thickness direction thereof, wherein the film sheet of the composite sheet faces toward the absorbent core.