Laminated nonwoven fabric, air purifier, and manufacturing method of laminated nonwoven fabric

1. A laminated nonwoven fabric comprising:

a first nonwoven fabric containing charged first fibers;

a second nonwoven fabric laminated on the first nonwoven fabric and containing second fibers;

an adhesive; and

a third nonwoven fabric laminated on the second nonwoven fabric and containing third fibers,

wherein a fiber diameter of the first fibers is greater than a fiber diameter of the second fibers,

wherein the first nonwoven fabric has a first surface and a second surface facing the second nonwoven fabric on an opposite side to the first surface,

wherein the second nonwoven fabric has a first surface facing the first nonwoven fabric and a second surface opposite to the first surface of the second nonwoven fabric,

the third nonwoven fabric is laminated on the second surface of the second nonwoven fabric, and

the adhesive is present in a first region spanning a first distance d 1 from the second surface of the first nonwoven fabric and the adhesive is present in a second region spanning a second distance d 2 from the first surface of the second nonwoven fabric, and the second distance d 2 is longer than the first distance d 1 .

2. The laminated nonwoven fabric according to claim 1 ,

wherein porosity of the third nonwoven fabric is greater than porosity of the first nonwoven fabric.

3. The laminated nonwoven fabric according to claim 2 ,

wherein the porosity of the first nonwoven fabric is in a range from 60% to 95% by volume, inclusive.

4. The laminated nonwoven fabric according to claim 1 ,

wherein a ratio d 1 /T 1 of the distance d 1 with respect to a thickness T 1 of the first nonwoven fabric is in a range from 0.1 to 0.5, inclusive.

5. The laminated nonwoven fabric according to claim 1 ,

wherein a thickness of the first nonwoven fabric is in a range from 100 μm to 500 μm, inclusive,

wherein a thickness of the second nonwoven fabric is in a range from 0.5 μm to 10 μm, inclusive, and

wherein a thickness of the third nonwoven fabric is in a range from 150 μm to 500 μm, inclusive.

6. The laminated nonwoven fabric according to claim 1 ,

wherein the fiber diameter of the second nonwoven fabric is more than 0 μm and less than 1 μm.

7. An air purifier comprising:

a sucker of a gas;

a discharger of the gas; and

the laminated nonwoven fabric according to claim 1 disposed between the sucker and the discharger,

wherein the first nonwoven fabric has a first surface and a second surface facing the second nonwoven fabric on an opposite side to the first surface, and the first surface faces the sucker.

8. A manufacturing method of a laminated nonwoven fabric, comprising:

preparing a first nonwoven fabric containing charged first fibers;

preparing a raw material liquid containing a raw material resin as a raw material of second fibers and a solvent dissolving the raw material resin;

preparing a third nonwoven fabric containing third fibers;

spraying the raw material liquid onto the third nonwoven fabric so that the second fibers are generated from the raw material liquid, and forming a second nonwoven fabric by accumulating the second fibers on the third nonwoven fabric;

spraying a solid adhesive onto a first surface of the second nonwoven fabric, the first surface being opposite to a second surface facing the third nonwoven fabric;

melting the solid adhesive sprayed onto the first surface; and

laminating the first nonwoven fabric on the first surface of the second nonwoven fabric having the melted adhesive.

9. A manufacturing method of the laminated nonwoven fabric according to claim 8 , wherein the adhesive is present in a first region spanning a first distance d 1 from the second surface of the first nonwoven fabric and the adhesive is present in a second region spanning a second distance d 2 from the first surface of the second nonwoven fabric, after the laminating, and the second distance d 2 is longer than the first distance d 1 .

10. The laminated nonwoven fabric according to claim 1 , wherein the second fibers of the second nonwoven fabric are not charged.