Fine fibers made from polymer crosslinked with resinous aldehyde composition

• US 9,587,328 B2
• Filed: 09/21/2012
• Issued: 03/07/2017
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Shenoy, Suresh L., Chung, Hoo Young, Weik, Thomas M.
• Primary Examiner(s): Bass, Dirk
• Application Number:
  US13/624,064
• Publication Number:
  US 20130068687A1
• Time in Patent Office: 1,628 Days
• Field of Search: 210/504, 428/378
• US Class Current: 1/1
• CPC Class Codes: B01D 2239/0233 Island-in-sea
• CPC Class Codes: B01D 2239/0618 Non-woven
• CPC Class Codes: B01D 2239/0622 Melt-blown
• CPC Class Codes: B01D 2239/0627 Spun-bonded
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material
• CPC Class Codes: B01D 2239/1291 Other parameters
• CPC Class Codes: B01D 39/163 sintered or bonded
• CPC Class Codes: D01D 5/0038 the fibre formed by solvent evaporation, i.e. dry electro-spinning
• CPC Class Codes: D01F 6/50 of polyalcohols, polyacetals or polyketals
• CPC Class Codes: D01F 6/90 of polyamides
• CPC Class Codes: D01F 6/94 of other polycondensation products
• CPC Class Codes: D01F 8/02 from cellulose, cellulose derivatives, or proteins
• CPC Class Codes: D01F 8/06 with at least one polyolefin as constituent
• CPC Class Codes: D01F 8/12 with at least one polyamide as constituent
• CPC Class Codes: D01F 8/16 with at least one other macromolecular compound obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds as constituent
• CPC Class Codes: D10B 2505/04 Filters
• CPC Class Codes: Y10T 428/2938 Coating on discrete and individual rods, strands or filaments

Abstract

A fine fiber can be made having a structure with an axial core and a coating layer. The fiber can have a polymer core and one or two layers surrounding the core. The fine fiber can be made from a polymer material and a resinous aldehyde (e.g., melamine-aldehyde) composition such that the general structure of the fiber has a polymer core surrounded by at least a layer of the resinous aldehyde composition.

Claims

1. A fine fiber comprising a core phase and a coating phase;

wherein the core phase comprises a polymer and the coating phase comprises a resinous aldehyde composition;

wherein at least a portion of the polymer is crosslinked by the resinous aldehyde composition;

wherein the resinous aldehyde composition is present in an amount of greater than or equal to 40 parts per weight per 100 parts per weight of the polymer and less than or equal to 100 parts by weight per 100 parts by weight of the polymer; and

further wherein the fine fiber does not include polyvinyl alcohol crosslinked with melamine-formaldehyde.

2. The fine fiber of claim 1 which is prepared from a resinous aldehyde composition comprising reactive alkoxy groups and a polymer comprising active hydrogen groups, wherein the molar ratio of resinous aldehyde composition to polymer is such that the molar ratio of reactive alkoxy groups to active hydrogen groups is greater than 10:

100.

3. The fine fiber of claim 2 wherein the active hydrogen groups comprise amido or amino groups.

4. The fine fiber of claim 1 comprising two phases, wherein the core phase comprises a mixture of the polymer and the resinous aldehyde composition.

5. The fine fiber of claim 1 comprising three phases, wherein the core phase comprises the polymer, the coating phase comprises the resinous aldehyde composition, and a transition phase comprises a mixture of the polymer and the resinous aldehyde composition.

6. The fine fiber of claim 1 wherein the polymer comprises a nylon.

7. The fine fiber of claim 6 wherein the nylon comprises nylon-6, nylon-6,6, nylon-6,10, mixtures or copolymers thereof.

8. The fine fiber of claim 7 wherein the nylon comprises nylon-6-6,6-6,10.

9. The fine fiber of claim 1 wherein the polymer comprises a polyvinyl butyral, an ethylene co-vinyl alcohol co-polymer, or a mixture thereof.

10. The fine fiber of claim 1 wherein the polymer comprises a cellulose derivative selected from the group consisting of ethyl cellulose, hydroxyl ethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, and mixtures thereof.

11. The fine fiber of claim 1 wherein the polymer comprises a poly(meth)acrylic acid homopolymer or copolymer.

12. The fine fiber of claim 11 wherein the polymer comprises a styrene-(meth)acrylic acid copolymer.

13. The fine fiber of claim 1 wherein the polymer comprises a poly(maleic anhydride) homopolymer or copolymer.

14. The fine fiber of claim 13 wherein the polymer comprises a styrene-maleic anhydride copolymer.

15. The fine fiber of claim 1 wherein the resinous aldehyde composition comprises a resinous formaldehyde composition.

16. The fine fiber of claim 15 wherein the resinous formaldehyde composition comprises a resinous melamine-formaldehyde composition.

17. The fine fiber of claim 1 wherein the resinous aldehyde composition comprises a melamine-aldehyde composition;

and wherein the aldehyde comprises formaldehyde, acetaldehyde, butyraldehyde, isobutyraldehyde, or mixtures thereof.

18. The fine fiber of claim 1 wherein the resinous aldehyde composition comprises a condensation product of urea and an aldehyde, a condensation product of phenol and an aldehyde, a condensation product of melamine and an aldehyde, or a mixture thereof.

19. The fine fiber of claim 1 wherein the resinous aldehyde composition comprises a condensation product of benzoguanamine and an aldehyde, a condensation product of glycoluril and an aldehyde, or a mixture thereof.

22. A filter media comprising a filtration substrate and a layer comprising a plurality of fine fibers of claim 1 disposed on the substrate.

23. The filter media of claim 22 wherein the fine fiber layer has a thickness of 0.05 μ

to 30 μ

.

24. The filter media of claim 22 wherein the filtration substrate is a non-woven substrate.

25. The filter media of claim 22 wherein the fine fiber layer is an electrospun layer and the filtration substrate comprises a cellulosic or synthetic nonwoven.

26. The filter media of claim 25 wherein the filtration substrate comprises a polyester nonwoven, a polyolefin nonwoven, or a blended nonwoven thereof.

27. The filter media of claim 26 wherein the filtration substrate comprises polypropylene nonwoven.

28. The filter media of claim 22 wherein the filtration substrate comprises a spunbonded or melt-blown support.

29. A filter element comprising a fine fiber filter media of claim 22.

20. A fine fiber comprising a core phase and a coating phase;

wherein the core phase comprises nylon and the coating phase comprises a resinous melamine-aldehyde composition;

wherein at least a portion of the nylon is crosslinked by the resinous melamine-aldehyde composition; and

further wherein the fine fiber is prepared from a resinous melamine-aldehyde composition in an amount of greater than 40 parts by weight per 100 parts by weight of the nylon and less than or equal to 100 parts by weight per 100 parts by weight of the polymer.

21. The fine fiber of claim 20 wherein the core phase further comprises a nonreactive polymer.

30. A fine fiber prepared by a method comprising

preparing a solution comprising a polymer and a resinous aldehyde composition;

and

electrospinning the solution to form the fine fiber, wherein

the fine fiber comprises a core phase and a coating phase,

the core phase comprises the polymer and the coating phase comprises the resinous aldehyde composition,

at least a portion of the polymer is crosslinked by the resinous aldehyde composition,

the resinous aldehyde composition is present in an amount of greater than or equal to 40 parts per weight per 100 parts per weight of the polymer and less than or equal to 100 parts by weight per 100 parts by weight of the polymer, and

the fine fiber does not include polyvinyl alcohol crosslinked with melamine-formaldehyde.