Filtration materials using fiber blends that contain strategically shaped fibers and/or charge control agents

• US 10,571,137 B2
• Filed: 03/17/2017
• Issued: 02/25/2020
• Est. Priority Date: 10/25/2010
• Status: Active Grant

• Current Assignee: Swm Luxembourg SARL (Mativ Holdings, Inc.)
• Original Assignee: DelStar Technologies Incorporated (Mativ Holdings, Inc.)
• Inventors: Chapman, Rick L.
• Primary Examiner(s): Orlando, Amber R
• Assistant Examiner(s): Turner, Sonji
• Application Number:
  US15/461,976
• Publication Number:
  US 20170189914A1
• Time in Patent Office: 1,075 Days
• CPC Class Codes: B01D 2239/0435 Electret apparatus incorporating such gas filtering material B01D46/0032
• CPC Class Codes: B01D 2239/0492 on fibres
• CPC Class Codes: B01D 2239/0627 Spun-bonded
• CPC Class Codes: B01D 2239/10 Filtering material manufacturing
• CPC Class Codes: B01D 2239/1233 Fibre diameter
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 46/0032 using electrostatic forces to remove particles, e.g. electret filters
• CPC Class Codes: B03C 3/28 Plant or installations without electricity supply, e.g. using electrets
• CPC Class Codes: D01D 5/06 Wet spinning methods D01D5/0046 takes precedence
• CPC Class Codes: D01D 5/253 with a non-circular cross section; Spinnerette packs therefor D01D5/38 takes precedence
• CPC Class Codes: D01F 1/00 General methods for the manufacture of artificial filaments or the like
• CPC Class Codes: D01F 1/09 for making electroconductive or anti-static filaments
• CPC Class Codes: D01F 1/10 Other agents for modifying properties
• CPC Class Codes: D01F 6/06 from polypropylene
• CPC Class Codes: D01F 6/38 comprising unsaturated nitriles as the major constituent
• CPC Class Codes: D04H 3/018 characterised by the shape
• CPC Class Codes: D06M 13/00 Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds D06M10/00, D06M14/00 take precedence; treatment with complexes of organic amines with inorganic substances D06M11/59; Such treatment combined with mechanical treatment
• CPC Class Codes: F24F 8/10 by separation, e.g. by filtering
• CPC Class Codes: F24F 8/192 by electrical means, e.g. by applying electrostatic fields or high voltages

Abstract

A filtration material comprising a blend of polypropylene and acrylic fibers of round, flat, dog bone, oval or kidney bean shape in any size from 0.08 to 3.3 Dtex. A preferred blend contains about 50 weight percent polypropylene fibers and about 50 weight percent acrylic fibers. The fibers can be blended ranging from 90:10 to 10:90 polypropylene to acrylic. The shape contains 25 weight percent round, flat, oval, dog bone and kidney bean shapes. The fiber blend contains 25 weight percent of at least one size between 0.08 and 3.3 Dtex. Electret fibers incorporated within these blends have 0.02 to 33 weight percent of a charge control agent. These fibers can be used in producing electret material by corona or triboelectric charging methods.

Claims

1. An electret gas filter media, the filter media comprising:

a plurality of non-woven fibers;

at least some of said non-woven fibers are acrylic fibers, at least some of said acrylic fibers are formed by a wet spinning process with a dog bone shaped cross section, and at least some of said acrylic fibers are formed by a dry spinning process and are three dimensionally crimped; and

further comprising about 0.5% to about 2% wax or other lubricant by weight on outer surfaces of at least some of said non-woven fibers.

2. The filter media in accordance with claim 1, wherein the filter media further comprises polypropylene fibers.

3. The filter media in accordance with claim 2, wherein at least some of the polypropylene fibers have a dog bone shaped cross section.

4. The filter media in accordance with claim 1, wherein a charge control agent or lubricant is disposed on the outer surfaces of at least some of the non-woven fibers.

5. An electret gas filter media, the filter media comprising:

a plurality of non-woven fibers, at least some of said non-woven fibers are polypropylene fibers with a non-round cross section, at least some of said polypropylene fibers having a dog bone shaped cross section; and

at least some of said non-woven fibers are acrylic fibers, at least some of said acrylic fibers being formed by a wet spinning process and having a dog bone shaped cross section, and at least some of said acrylic fibers being formed by a dry spinning process and are three dimensionally crimped.

6. The filter media in accordance with claim 5, wherein a ratio of the polypropylene fibers to the acrylic fibers is in a range from about 90:

10 to about 10;

90.

7. The filter media in accordance with claim 5, further comprising a charge control agent or lubricant disposed on outer surfaces of at least some of the non-woven fibers.

8. The filter media in accordance with claim 7, wherein said charge control agent or lubricant is selected from the group consisting of organic wax, non-organic wax and PVDF.

9. An electret gas filter media, the filter media comprising:

a plurality of non-woven fibers;

at least some of said non-woven fibers are polypropylene fibers,

at least some of said non-woven fibers are acrylic fibers formed by a wet spinning process and having a non-round shaped cross section; and

at least some of said non-woven fibers are acrylic fibers formed by a dry spinning process and having a dog bone shaped cross section, and further being three dimensionally crimped.

10. The filter media in accordance with claim 9, wherein a ratio of the polypropylene fibers to the acrylic fibers is in a range from about 90:

10 to about 10;

90.

11. The filter media in accordance with claim 10, further comprising a charge control agent or lubricant disposed on outer surfaces of at least some of the non-woven fibers.

12. The filter media in accordance with claim 10, wherein the polypropylene fibers have a non-round shaped cross section.

13. The filter media in accordance with claim 10, wherein the polypropylene fibers have a round cross section.