Filter rod including electrostatically charged fibers

Patent metadata

Field	Value
Publication number	US-10226070-B2
Application number	US-201715704332-A
Country	US
Kind code	B2
Filing date	Sep 14, 2017
Priority date	Oct 9, 2009
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A filter rod comprises a core of cellulose acetate fibers surrounded by a lofty porous network of charge retaining polymer fibers. The charge retaining fibers can be charged to attract and hold particles from such sources as particulate matter from sorbents (preventing break-through), and smoke constituents while having a suitable pressure drop.

First claim

We claim:

1. A filter rod for a smoking article, comprising:
a core of cellulose acetate fibers;
a lofty porous network of charge retaining polymer fibers surrounding the core of cellulose acetate fibers;
a filter wrap surrounding the lofty porous network
wherein the lofty porous network includes mediating fibers of non-charge retaining fibers.

2. The filter rod of claim 1 , wherein the lofty porous network has an airspace of 20% to 40% by volume, 40% to 60% by volume, 60% to 80% by volume, or 80% to 95% by volume and the lofty porous network contains solid or liquid flavorant.

3. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polyethylene fibers.

4. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polypropylene fibers.

5. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polyvinylidene difluoride fibers.

6. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polytetrafluoroethylene fibers.

7. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged nylon fibers.

8. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polyester fibers.

9. The filter rod of claim 1 , wherein the charge retaining polymer comprises electrostatically charged polyamide fibers.

10. The filter rod of claim 1 , wherein the mediating fibers are non-charged polyester fibers.

11. The filter rod of claim 1 , wherein the mediating fibers are cellulose acetate fibers.

12. The filter rod of claim 1 , wherein the mediating fibers are bonded to the charge retaining polymer fibers.

13. The filter rod of claim 12 , wherein the mediating fibers are thermally bonded to the charge retaining polymer fibers.

14. The filter rod of claim 1 , wherein the charge retaining polymer fibers have a random orientation.

15. The filter rod of claim 1 , wherein the charge retaining polymer fibers are electrostatically charged.

16. A filter assembly comprising the filter rod of claim 1 and an upstream sorbent.

17. The filter assembly of claim 16 , wherein the sorbent comprises activated carbon and a plug of axially oriented cellulose acetate fibers is upstream of the activated carbon.

18. The filter assembly of claim 16 , wherein the sorbent comprises particles, granules, beads or fibers of activated carbon located in a cavity and a plug of axially oriented cellulose acetate fibers is upstream of the cavity.

19. The filter assembly of claim 16 , wherein the sorbent comprises activated carbon particles in a plug of filter material, the charge retaining polymer fibers having permanent electrostatic charges effective to capture activated carbon particles entrained in mainstream smoke passing through the lofty porous network.

Assignees

• Philip Morris Usa Inc

Inventors

• Yang Szu-Sung
• Xue Lixin L
• Chang Jing C

Classifications

• A24D3/04

  Tobacco smoke filters characterised by their shape or structure · CPC title

• A24D3/063

  of the fibers · CPC title

• A24D3/02 Primary

  Manufacture of tobacco smoke filters · CPC title

• A24D3/0204

  Preliminary operations before the filter rod forming process, e.g. crimping, blooming (A24D3/0275 takes precedence) · CPC title

• A24D3/163

  Carbon · CPC title