Tackified And Non-Tackified Nonwovens Of Controlled Stiffness And Retained Foldability

• US 20080120954A1
• Filed: 11/08/2007
• Published: 05/29/2008
• Est. Priority Date: 05/16/2006
• Status: Abandoned Application

• Current Assignee: Polyester Fibers, LLC
• Original Assignee: Polyester Fibers, LLC
• Inventors: Peart, Christopher B., Nance, Nathaniel J., DUELLO, Leonard E., Hawkins, Thomas D.
• Application Number:
  US11/937,245
• Publication Number:
  US 20080120954A1
• Time in Patent Office: Days
• US Class Current: 55/528
• CPC Class Codes: B01D 2239/0216 Bicomponent or multicomponent fibres
• CPC Class Codes: B01D 39/163 sintered or bonded
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 442/60 Nonwoven fabric [i.e., nonwoven strand or fiber material]

Abstract

The present disclosure relates generally to a nonwoven filtration media comprising a bonded mix of different, discontinuous, thermoplastic resin fibers and optionally discontinuous cellulosic fibers. In some embodiments a tackifier is added to the nonwoven filtration media to provide a sticky or adhesive surface on the fibers. The nonwoven media has an advantageous combination of stiffness, foldability, efficiency and the ability to retain a fold. The nonwoven media can be thermally bonded during the production process. The advantageous combination of mechanical properties allow the disclosed nonwoven media to accept and retain folds and pleats better than some conventional filtration materials while the mix of different fibers provides desirable filtration properties.

Claims

1. A tackified air filtration media comprising a thermally bonded nonwoven web comprising a generally homogeneous mixture of fiber types, the web comprising about 10% to about 90% by weight of a first type of fibers having a length of about 0.6 cm to about 20 cm, the fibers including a first fiber portion extending substantially continuously along the length of each fiber and comprising a first thermoplastic polymeric material having a first melting point and a second fiber portion extending substantially continuously along the length of each fiber and defining at least a portion of a fiber exterior surface, the second fiber portion comprising a second thermoplastic polymeric material having a second melting point lower than the first melting point, and about 10% to about 90% by weight of a second type of fibers having a length of about 0.6 cm to about 20 cm;

the media having a basis weight in the range of about 90 gsm to about 370 gsm;

a thickness of about 1.0 mm to about 6.4 mm;

a Frazier permeability of about 150 CFM/square foot to about 1000 CFM/square foot; and

a combination of MD Gurley stiffness and LED score results selected from one of the following ranges;

2. The tackified air filtration media of claim 1, wherein the first thermoplastic polymeric material is polyester.

3. The tackified air filtration media of claim 1 being a single layer.

4. The tackified air filtration media of claim 1, wherein the first thermoplastic polymeric material is polyester and the second thermoplastic polymeric material is polyester.

5. The tackified air filtration media of claim 1, further comprising kenaf fibers having a length of about 0.6 cm to about 20 cm.

6. The tackified air filtration media of claim 1, comprising about 1.5% to about 15% of the tackifier on fibers of the air filtration media.

7. The tackified air filtration media of claim 1, wherein one fiber type has a denier in the range of about 0.9 to about 6 and the other fiber type has a denier in the range of about 8 to about 45.

8. The tackified air filtration media of claim 1, further being a self supporting media.

9. The tackified air filtration media of claim 1, having a MD Gurley stiffness over 1700.

10. The tackified air filtration media of claim 1, wherein:

the first fiber type is selected from at least one of about 10% to about 85% 4 denier conjugate fibers comprising polyester first and second fiber portions or about 10% to about 85% 15 denier conjugate fibers comprising polyester first and second fiber portions;

the second fiber type is selected from at least one of about 5% to about 30% monocomponent polyester fibers having a denier in the range of about 0.9 to about 45;

about 15% to about 50% 3 denier chargeable polypropylene fibers;

about 15% to about 30% polyester/cotton blend fibers;

or about 15% to about 35% cellulosic fibers;

at least one fiber type has a denier greater than 10; and

about 1.5% to about 6% tackifier.

11. The tackified air filtration media of claim 1 further comprising a cured, non-fibrous binder resin between the fiber types.

12. The tackified air filtration media of claim 1 having a combination of Gurley stiffness and LED score results selected from one of the following ranges:

13. A method of making a tackified air filtration media comprising:

forming a fiber mixture, comprising about 10% to about 90% by weight of a first type of fibers having a length of about 0.6 cm to about 20 cm, the fibers including a first fiber portion extending substantially continuously along the length of each fiber and comprising a first thermoplastic polymeric material having a first melting point and a second fiber portion extending substantially continuously along the length of each fiber and defining at least a portion of a fiber exterior surface, the second fiber portion comprising a second thermoplastic polymeric material having a second melting point lower than the first melting point, and about 10% to about 90% by weight of a second type of fibers having a length of about 0.6 cm to about 20 cm;

forming the fiber mixture into a nonwoven matt;

bonding the fibers in the nonwoven matt, the bonded nonwoven matt having a basis weight in the range of about 90 gsm to about 370 gsm;

a thickness of about 1.0 mm to about 6.4 mm;

a Frazier permeability of about 150 CFM/square foot to about 1000 CFM/square foot; and

a combination of MD Gurley stiffness and LED score results selected from one of the following ranges;

14. The method of claim 13 wherein the step of forming comprises carding the fiber mixture to form the nonwoven matt.

15. The method of claim 13 wherein the step of forming comprises carding the fiber mixture to form a web and cross lapping the web to form the nonwoven matt.

16. The method of claim 13 wherein the step of bonding comprises thermal bonding of the fibers in the nonwoven matt.

17. The method of claim 13 wherein the step of applying comprises spraying a tackifier on a surface of the bonded nonwoven matt.

18. The method of claim 13 further comprising the step of folding the media to form a self supporting structure.

19. A non-tackified air filtration media comprising a thermally bonded nonwoven web comprising a generally homogeneous mixture of fiber types, the web comprising about 30% to about 90% by weight of a first type of fibers having a length of about 0.6 cm to about 20 cm, the fibers including a first fiber portion extending substantially continuously along the length of each fiber and comprising a first thermoplastic polymeric material having a first melting point and a second fiber portion extending substantially continuously along the length of each fiber and defining at least a portion of a fiber exterior surface, the second fiber portion comprising a second thermoplastic polymeric material having a second melting point lower than the first melting point, and about 5% to about 70% by weight of a second type of fibers having a length of about 0.6 cm to about 20 cm;

the media having a basis weight in the range of about 90 gsm to about 370 gsm;

a thickness of about 1.0 mm to about 6.4 mm;

a Frazier permeability of about 45,000 LSM to about 260,000 LSM; and

a combination of Gurley stiffness and LED score results selected from one of the following ranges;

20. The non-tackified air filtration media of claim 19, wherein one fiber type has a denier less than about 6 and the other fiber type has a denier greater than about 8.