Filter medium for liquid filter and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-2016136584-A1
Application number	US-201615000347-A
Country	US
Kind code	A1
Filing date	Jan 19, 2016
Priority date	Aug 6, 2013
Publication date	May 19, 2016
Grant date	—

Abstract

Provided are filter media for liquid filters and a method of manufacturing the same, in which a thin filter layer is formed and the content of nanofibers weighs light, by laminating a low weight nanofiber web on a porous nonwoven fabric, and thus a less differential pressure is applied before and after filtering, to thereby increase a pass flow rate. The filter medium includes: a porous support that plays a strength support role; and a nanofiber web that is laminated on one side of the porous support and is made of nanofibers of a polymer material, in which the nanofiber web comprises fine pores of a three-dimensional structure, through which a liquid to be treated passes, wherein content of the nanofibers is less than 5 gsm.

First claim

1 . A filter medium for liquid filters, the filter medium comprising:
a porous support that plays a strength support role; and a nanofiber web that is laminated on one side of the porous support and is made of nanofibers of a polymer material, in which the nanofiber web comprises fine pores of a three-dimensional structure, through which a liquid to be treated passes, wherein content of the nanofibers is less than 5 gsm.

2 . The filter medium of claim 1 , wherein the content of the nanofibers is set to range from 2 to 3 gsm.

3 . The filter medium of claim 1 , wherein thickness of the nanofiber web is set to range from 2 to 6 μm, and a pore size thereof is set to 0.2 to 3 μm.

4 . The filter medium of claim 1 , wherein diameter of the nanofibers is set to range from 100 to 800 nm.

5 . The filter medium of claim 4 , wherein diameter of the nanofibers is set to range from 150 to 300 nm.

6 . The filter medium of claim 1 , wherein the porous support is a nonwoven fabric.

7 . The filter medium of claim 6 , wherein the nonwoven fabric is made of a PP/PE nonwoven fabric in which PE is coated on an outer periphery of a PP fiber as a core, wherein the PP/PE nonwoven fabric is combined with the nanofibers by melting a PE coating portion coated on an outside of the PP fiber, and wherein the PP fiber maintains a porous structure.

8 . The filter medium of claim 6 , wherein the nonwoven fabric is made of a PET (polyethyleneterephthalate) nonwoven fabric in which a low melting point PET is coated on an outer periphery of a regular PET fiber as a core, wherein the PET nonwoven fabric is combined with the nanofibers by melting the low melting point PET coated on the outer periphery of the regular PET fiber, and wherein the regular PET fiber maintains a porous structure.

9 . The filter medium of claim 1 , wherein the nanofibers are configured so that ion exchange resin particles are dispersed inside or on the surfaces of the nanofibers.

10 . The filter medium of claim 8 , wherein the ion exchange resin particles are particles of a porous organic polymer with an ion exchange capacity or particles of a copolymer of polystyrene and divinylbenzene.

11 . A method of manufacturing a filter medium of liquid filters, the method comprising:
electrospinning a spinning solution that is formed by mixing a polymer material with a solvent on a transfer sheet, thereby forming a nanofiber web having fine pores of a three-dimensional structure; performing a primary calendering process of combining the nanofibers and simultaneously adjusting pore sizes and thicknesses of the nanofiber web; and performing a secondary calendering process of laminating the nanofiber web having undergone the first calendaring process on a porous support to thus form the filter medium.

12 . The method of claim 11 , wherein the primary calendering process is performed at a higher temperature than that of the secondary calendering process.

13 . The method of claim 12 , wherein the primary calendering process is set at a temperature capable of combining the nanofibers to form a nanofiber web, and wherein the secondary calendering process is set at a temperature identical to a melting point of a coating portion having the melting point lower than that of a core of a double core fiber forming a porous support, in which the coating portion is melted and combined with the nanofibers.

14 . The method of claim 13 , wherein the porous support is a PP/PE nonwoven fabric in which PE fiber is coated on an outer periphery of a PP fiber as a core, or a PET (polyethyleneterephthalate) nonwoven fabric in which low melting point PET is coated on an outer periphery of a regular PET fiber as a core.

15 . The method of claim 11 , further comprising preheating the porous support at a temperature lower than that of the secondary calendering process before executing the secondary calendaring process.

16 . The method of claim 11 , wherein the transfer sheet is any one of paper, a nonwoven fabric made of a polymeric material that is not dissolved by the solvent contained in the spinning solution, and a polyolefin-based film.

17 . The method of claim 11 , wherein thickness of the nanofiber web is set to range from 2 to 6 μm, and a pore size thereof is set to 0.2 to 3 μm.

18 . The method of claim 11 , wherein content of the nanofibers is less than 5 gsm.

19 . The method of claim 11 , wherein the spinning solution further comprises ion exchange resin particles or Ag salts, in which the nanofibers are configured so that the ion exchange resin particles or the Ag metal salts are dispersed inside or on the surfaces of the nanofibers.

Assignees

• Amogreentech Co Ltd

Inventors

• Hwang Jun Sik
• Seo In Yong

Classifications

• B01D2325/42

  Ion-exchange membranes · CPC title

• B32B5/08

  the fibres or filaments of a layer being of different substances {, e.g. conjugate fibres, mixture of different fibres} · CPC title

• B01D2239/0654

  Support layers · CPC title

• B32B2262/0276

  Polyester fibres · CPC title

• B32B2264/0228

  Vinyl resin particles, e.g. polyvinyl acetate, polyvinyl alcohol polymers or ethylene-vinyl acetate copolymers · CPC title