Antimicrobial nonwoven polyamides with zinc content

Patent metadata

Field	Value
Publication number	US-11758909-B2
Application number	US-201916719308-A
Country	US
Kind code	B2
Filing date	Dec 18, 2019
Priority date	Dec 18, 2018
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

The present disclosure relates to a nonwoven polyamide structure having antimicrobial properties comprising: nonwoven polyamide fibers comprising less than 4000 ppm zinc dispersed within the nonwoven polyamide fibers; and less than 2000 ppm phosphorus. The fibers have an average fiber diameter of less than 25 microns; and the polyamide structure demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

First claim

We claim:

1. A nonwoven polyamide structure having antimicrobial properties comprising:
nonwoven polyamide fibers comprising a polyamide composition comprising:
less than 4000 ppm zinc dispersed within the nonwoven polyamide fibers; and
less than 2000 ppm phosphorus,
wherein the fibers have an average fiber diameter of less than 20 microns;
wherein the zinc is provided via a zinc compound and the phosphorus is provided via a phosphorus compound different from the zinc compound; and
wherein the polyamide structure demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

2. The nonwoven polyamide structure of claim 1 , wherein the weight ratio of the zinc to the phosphorus is at least 1.3:1; or less than 0.64:1.

3. The nonwoven polyamide structure of claim 1 , wherein the relative viscosity of the polyamide composition is less than 100.

4. The nonwoven polyamide structure of claim 1 , wherein the polyamide composition comprises less than 3100 ppm of zinc, wherein the polyamide composition comprises a delusterant including at least a portion of the phosphorus, and wherein the polyamide demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

5. The nonwoven polyamide structure of claim 1 , wherein no more than 20% of the fibers have a diameter of greater than 700 nanometers.

6. The nonwoven polyamide structure of claim 1 , wherein the polyamide comprises nylon 66 or nylon 6/66.

7. Antimicrobial fibers having antimicrobial properties comprising:
a polymer;
less than 4000 ppm zinc dispersed within the polymer; and
less than 2000 ppm phosphorus,
wherein the fibers have an average fiber diameter of less than 20 microns;
wherein the zinc is provided via a zinc compound and the phosphorus is provided via a phosphorus compound different from the zinc compound; and
wherein the antimicrobial fibers demonstrate a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

8. The antimicrobial fibers of claim 7 , wherein the weight ratio of zinc to phosphorus is: at least 1.3:1; or less than 0.64:1.

9. The antimicrobial fibers of claim 7 , wherein the antimicrobial fibers comprise less than 3100 ppm of zinc.

10. The antimicrobial fibers of claim 7 , wherein the antimicrobial fibers have a zinc retention greater than 70% as measured by a dye bath test.

11. The antimicrobial fibers of claim 7 , wherein the antimicrobial fibers comprise less than 3200 ppm of zinc, wherein the antimicrobial fibers comprise a delusterant including at least a portion of the phosphorus, and wherein the antimicrobial fibers demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

12. The antimicrobial fibers of claim 7 , wherein the antimicrobial fibers comprise nylon 66 or nylon 6/66.

13. A process for preparing an antimicrobial nonwoven polyamide structure having permanent antimicrobial properties, the process comprising:
preparing precursor polyamide comprising an aqueous monomer solution;
dispersing less than 4000 ppm zinc within the precursor polyamide;
dispersing less than 2000 ppm phosphorus within the precursor polyamide;
wherein the zinc is provided via a zinc compound and the phosphorus is provided via a phosphorus compound different from the zinc compound;
polymerizing the precursor polyamide to form a polyamide composition;
spinning the polyamide composition to form antimicrobial polyamide fibers; and
forming the antimicrobial polyamide fibers into the antimicrobial nonwoven structure having a fiber diameter of less than 20 microns; and
wherein the polyamide structure demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

14. The process of claim 13 , wherein the antimicrobial nonwoven polyamides have a zinc retention greater than 70% as measured by a dye bath test.

15. The process of claim 13 , wherein the weight ratio of zinc to phosphorus is: at least 1.3:1 or less than 0.64:1.

16. The process of claim 13 , wherein the polyamide is melt spun by way of melt blowing through a die into a high velocity gaseous stream.

17. A process for preparing an antimicrobial nonwoven polyamide structure having antimicrobial properties, the process comprising:
preparing a formulation comprising a polyamide, less than 4000 ppm zinc dispersed within the polyamide; and less than 2000 ppm phosphorus dispersed within the polyamide, wherein the zinc is provided via a zinc compound and the phosphorus is provided via a phosphorus compound different from the zinc compound;
spinning the formulation to form antimicrobial polyamide fibers having a fiber diameter c less than 20 microns; and
forming the antimicrobial polyamide fibers into antimicrobial nonwoven polyamide structure;
wherein the fibers were spun using a die pressure less than 275 psig; and
wherein the polyamide structure demonstrates a Staphylococcus Aureus reduction of at least 90%, as measured by ISO 20743-13.

Assignees

• Ascend Performance Mat Operations Llc

Inventors

• Osborn Scott E
• Yung Wai-Shing
• Ortega Albert

Classifications

• D01F1/103 Primary

  Agents inhibiting growth of microorganisms · CPC title

• D04H1/4334 Primary

  Polyamides · CPC title

• A01N57/00 Primary

  Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds · CPC title

• D01F6/60

  from polyamides (from polyamino acids or polypeptides D01F6/68) · CPC title

• D04H3/009

  Condensation or reaction polymers · CPC title