Nonwoven fabric, air purifier using the same, and method for producing nonwoven fabric

Patent metadata

Field	Value
Publication number	US-2016199765-A1
Application number	US-201514977976-A
Country	US
Kind code	A1
Filing date	Dec 22, 2015
Priority date	Jan 8, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A nonwoven fabric includes a nanofiber. The nanofiber includes a core portion and a sheath portion covering at least a part of a surface of the core portion. The core portion includes a first polymer. The sheath portion includes a second polymer. The second polymer is smaller in polarity than the first polymer.

First claim

What is claimed is:

1 . A nonwoven fabric comprising:
a nanofiber comprising a core portion and a sheath portion covering at least a part of a surface of the core portion, wherein the core portion comprises a first polymer; wherein the sheath portion comprises a second polymer; and wherein the second polymer is smaller in polarity or in dielectric constant than the first polymer.

2 . The nonwoven fabric according to claim 1 , wherein the nanofiber is formed by an electric field spinning method.

3 . The nonwoven fabric according to claim 1 , wherein an amount of the second polymer is 10 to 1,000 parts by mass based on 100 parts by mass of the first polymer.

4 . The nonwoven fabric according to claim 1 , wherein the nanofiber has an exposed portion where at least a part of the surface of the core portion is exposed.

5 . The nonwoven fabric according to claim 4 , wherein in the surface of the core portion, an area of the exposed portion is greater than an area of the sheath portion.

6 . A nonwoven fabric comprising:
a nanofiber comprising a core portion and a sheath portion covering at least a part of a surface of the core portion; wherein the core portion comprises a first polymer; wherein the sheath portion comprises a second polymer; wherein the second polymer is a polyurethane; and wherein the first polymer is a polymer that is higher in hydrolysis resistance than the second polymer.

7 . The nonwoven fabric according to claim 6 , wherein an average of D f /D c that is a ratio of a fiber diameter D f of the nanofiber to a diameter D c of the core portion is 1.4 to 5.

8 . An air purifier, comprising:
a suction portion for gas; an ejection portion for the gas; and the nonwoven fabric according to claim 1 , which is disposed between the suction portion and the ejection portion.

9 . A method for producing a nonwoven fabric, comprising
a first step of preparing a first solution containing a first polymer or a precursor of the first polymer and a second polymer having smaller polarity than the first polymer; and a second step of producing a nanofiber by an electrostatic force from the first solution in a nanofiber-forming space and accumulating the produced nanofiber, thereby forming a nonwoven fabric, wherein the nanofiber comprises a core portion and a sheath portion covering at least a part of a surface of the core portion; wherein the core portion comprises the first polymer; and wherein the sheath portion comprises the second polymer.

10 . The method for producing a nonwoven fabric according to claim 9 , wherein the first step comprises:
a step (a) of preparing a first polymer solution comprising the first polymer and a first solvent for dissolving the first polymer; a step (b) of preparing a second polymer solution comprising the second polymer and a second solvent for dissolving the second polymer therein; a step (c) of mixing the first polymer solution and the second polymer solution; and a step (d) of separating a solution comprising the first polymer and the second polymer as the first solution from a mixture obtained in the step (c).

11 . The method for producing a nonwoven fabric according to claim 10 , wherein the second solvent is smaller in polarity than the first solvent.

12 . The method for producing a nonwoven fabric according to claim 10 , wherein the first polymer comprised in the first polymer solution has plural peaks in a molecular weight distribution.

13 . The method for producing a nonwoven fabric according to claim 9 , wherein a molecular weight distribution width of the first polymer comprised in the first solution is narrower than a molecular weight distribution width of the second polymer.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Motomura Koji
• Yamaguchi Takayoshi
• Yoshioka Yuki

Classifications

• B01D39/1623 Primary

  of synthetic origin · CPC title

• B01D2239/06

  Filter cloth, e.g. knitted, woven non-woven; self-supported material · CPC title

• D04H1/005

  Making three-dimensional articles by consolidation (D04H1/22 takes precedence) · CPC title

• B01D46/00

  Filters or filtering processes specially modified for separating dispersed particles from gases or vapours (filtering elements B01D24/00-B01D35/00; filtering material B01D39/00; their regeneration outside the filters B01D41/00) · CPC title

• B01D39/083

  of organic material · CPC title