Non-woven electret fibrous webs and methods of making same

Patent metadata

Field	Value
Publication number	US-9802187-B2
Application number	US-201214125329-A
Country	US
Kind code	B2
Filing date	Jun 27, 2012
Priority date	Jun 30, 2011
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A non-woven electret fibrous web for electrostatic adsorption and odor elimination and the preparation process thereof. In certain exemplary embodiments, the non-woven electret fibrous web includes a multiplicity of electret fibers, at least one of a plurality of photo-catalytic fibers or a plurality of multi-component fibers; and optionally, at least one of a plurality of chemically-active particulates, a plurality of carbon-based fibers, or a plurality of mono-component thermoplastic fibers. In other exemplary embodiments, carding and cross-lapping or air-laying processes are disclosed for making nonwoven fibrous webs including electret fibers and one or more of photocatalytic fibers, chemically-active particulates, multi-component fibers, mono-component thermoplastic fibers, or carbon-based fibers. In some exemplary embodiments, exemplary non-woven electret fibrous webs of the disclosure exhibit superior gas permeation characteristics, high adsorption characteristics for airborne contaminants, as well as an odor elimination function.

First claim

The invention claimed is:

1. A non-woven electret fibrous web comprising:
a single layer including a plurality of randomly oriented discrete fibers, the fibers including:
a plurality of electret fibers;
a plurality of photo-catalytic fibers;
a plurality of multi-component fibers; and optionally,
at least one of a plurality of chemically-active particulates, a plurality of carbon-based fibers or a plurality of mono-component thermoplastic fibers.

2. The non-woven electret fibrous web of claim 1 comprising a plurality of photo-catalytic fibers, wherein the weight ratio of the electret fibers to the photo-catalytic fibers is 1:19 to 19:1.

3. The non-woven electret fibrous web of claim 1 comprising a plurality of multi-component fibers, wherein the weight percentage of the multi-component fibers in the non-woven electret fibrous web is greater than 0% and less than 10% by weight, based on the total weight of the non-woven electret fibrous web.

4. The non-woven electret fibrous web of claim 1 comprising a plurality of chemically-active particulates in the form of granulated activated carbon, wherein the weight percentage of the chemically-active particulates is from 10% to 60% by weight, based on the total weight of the non-woven electret fibrous web, optionally wherein the non-woven electret fibrous web is pleated.

5. The non-woven electret fibrous web of claim 1 , wherein the non-woven electret fibrous web further comprises a plurality of carbon-based fibers selected from a bamboo charcoal fiber and a coconut charcoal fiber, wherein the weight percentage of the carbon-based fibers in the non-woven electret fibrous web is 30 to 85% by weight, the weight percentage of the electret fibers in the non-woven electret fibrous web is 10 to 60% by weight, the weight percentage of the chemically-active particulates if present in the non-woven electret fibrous web is 10% to 60% by weight, and the weight percentage of the photo-catalytic fibers if present in the non-woven electret fibrous web is 5 to 20% by weight, based on the total weight of the non-woven electret fibrous web.

6. The non-woven electret fibrous web of claim 1 , wherein the non-woven electret fibrous web further comprises a plurality of mono-component thermoplastic fibers, wherein the weight percentage of the mono-component thermoplastic fibers in the non-woven electret fibrous web is 5 to 30% by weight, the weight percentage of the electret fibers in the non-woven electret fibrous web is 5 to 60% by weight, the weight percentage of the carbon-based fibers if present in the non-woven electret fibrous web is 30 to 85% by weight, the weight percentage of the photo-catalytic fibers if present in the non-woven electret fibrous web is 5% to 80% by weight, and the weight percentage of the chemically-active particulates if present in the non-woven electret fibrous web is 10% to 60% by weight, based on the total weight of the non-woven electret fibrous web.

7. The non-woven electret fibrous web of claim 1 , wherein the electret fibers are comprised of dielectric (co)polymeric fibers that have been subjected to an electrostatic charging process.

8. The non-woven electret fibrous web of claim 1 , wherein the photo-catalytic fibers are selected from honey comb photo-catalytic fibers, synthetic fibers coated with nano-grade photo-catalytic particulates, and combinations thereof.

9. The non-woven electret fibrous web of claim 1 , wherein the electret fibers have lengths of 10-100 nm, and cross sections that are circular or rectangular.

10. The non-woven electret fibrous web of claim 1 , wherein the photo-catalytic fibers have lengths of 10-100 nm and fineness values of 0.5-20 deniers.

11. The non-woven electret fibrous web of claim 1 , wherein the mono-component thermoplastic fibers are selected from a polyethylene terephthalate (PET) mono-component thermoplastic fiber, a polyethylene (PE) mono-component thermoplastic fiber, or a poly lactic acid (PLA) mono-component thermoplastic fiber.

12. The non-woven electret fibrous web of claim 1 , wherein the non-woven electret fibrous web has a Basis Weight of 40 to 250 gsm.

13. A process for preparing the non-woven electret fibrous web according to claim 1 , comprising the steps of:
subjecting the electret fibers that are present, the photo-catalytic fibers that are present, the multi-component fibers that are present, the mono-component thermoplastic fibers if present, the plurality of chemically-active particulates if present, and the carbon-based fibers if present, to the following treatments to form the non-woven electret fibrous web:
opening the fibers that are present,
mixing the fibers that are present,
delivering the fibers that are present and the chemically-active particulates that are present to a feeding device,
then forming the non-woven electret fibrous web from the fibers that are present and the chemically-active particulates that are present by at least one of carding and cross-lapping or air-laying, and
thereafter bonding the formed non-woven electret fibrous web, optionally wherein the bonded non-woven electret fibrous web has a Basis Weight of 40 to 250 gsm.

14. The process according to claim 13 , wherein forming the non-woven electret fibrous web by carding and cross-lapping further comprises the steps of:
delivering the fibers that are present into a coarse opening apparatus to coarsely open the fibers;
then delivering the coarsely opened fibers to a mixing apparatus to mechanically mix the fibers;
then subjecting the mechanically mixed fibers to a fine opening treatment;
then introducing the treated fibers into a feeding device for feeding the fibers uniformly;
then feeding the treated fibers to a carding machine for forming a substantially uniform non-woven electret fibrous web;
then subjecting the substantially uniform non-woven electret fibrous web to a cross-lapping process; and
then subjecting the cross-lapped non-woven electret fibrous web to a needle punching process.

15. The process according of claim 13 , wherein forming the non-woven electret fibrous web by air-laying further comprises the steps of:
delivering the fibers that are present into a coarse opening apparatus to coarsely open the fibers;
then delivering the coarsely opened fibers to a mixing apparatus to mechanically mix the fibers;
then subjecting the mechanically mixed fibers to a fine opening treatment;
then introducing the treated fibers into a feeding device for feeding the treated fibers uniformly;
then feeding the treated fibers to an air-laying machine to form a substantially uniform non-woven electret fibrous web; and
then subjecting the substantially uniform non-woven electret fibrous web to a needle punching process.

16. The process according to claim 13 , comprising the steps of:
delivering the fibers that are present into a coarse opening apparatus to coarsely open the fibers;
then delivering the coarsely opened fibers to a mixing apparatus to mechanically mix the fibers;
then subjecting the mechanically mixed fibers to a fine opening treatment;

then introducing the treated fibers into a feeding device for feeding the treated fibers substantially uniformly;
then feeding the treated fibers to a carding machine to produce a substantially uniform non-woven electret fibrous web;
then subjecting the substantially uniform non-woven electret fibrous web to a cross-lapping process; and
then subjecting the cross-lapped non-woven electret fibrous web to a through-air bonding process.

17. The process according to claim 13 , comprising the steps of:
de

Assignees

• Fu Xiaoshuan
• Chen Rui
• Xu Qiang
• Le Normand Jean
• Both Hendrik
• Wu Tien T
• Fox Andrew R
• 3M Innovative Properties Co

Inventors

• Fu Xiaoshuan
• Chen Rui
• Xu Qiang
• Le Normand Jean
• Both Hendrik
• Wu Tien T
• Fox Andrew R

Classifications

• B01J35/39

  Photocatalytic properties · CPC title

• B01J35/45

  Nanoparticles · CPC title

• D04H1/43832

  side-by-side · CPC title

• D04H1/4383

  sea-island · CPC title

• D04H1/43835

  Mixed fibres, e.g. at least two chemically different fibres or fibre blends · CPC title