Method and apparatus for manufacture of smoking article filter assembly including electrostatically charged fibers

Patent metadata

Field	Value
Publication number	US-9788572-B2
Application number	US-201313969904-A
Country	US
Kind code	B2
Filing date	Aug 19, 2013
Priority date	Oct 9, 2009
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Provided are a method and apparatus for making a cigarette filter assembly for potentially reducing particle breakthrough. The method includes forming a lofty porous network of charge retaining polymer fibers by mechanical, chemical or thermal bonding of the fibers, wrapping the lofty porous network in a cylindrical or tubular shape with optional mediating filter fibers in a filter paper to form a filter plug while maintaining the lofty structure. 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. The apparatus handles the lofty media with minimal crushing, for example, by spacing apart delivery rolls equipped with protrusions to punch, push, and/or pull the lofty media ahead for high speed operation.

First claim

We claim:

1. An apparatus for manufacturing a filter assembly for a smoking article comprising:
a source of lofty porous network of charge retaining polymer fibers for forming into a filter rod having a pressure drop;
first and second rollers to move the lofty porous network through a gap defined between faces of the first and second rollers to a wrapping unit, wherein the first and second rollers move the lofty porous network through the gap without substantially crushing the lofty porous network;
a wrapping unit to pre-form a filter wrap into a cylindrical tube for surrounding the lofty porous network to form the filter rod, wherein the lofty porous network is pulled into the preformed cylindrical tube to fill the pre-formed tube with the lofty porous network;
a charging unit to charge the charge retaining polymer fibers before or after passing the first and second rollers or the wrapping unit; and
a cutting unit to cut the filled preformed cylindrical tube to a predetermined length.

2. The apparatus of claim 1 , wherein the first roller and/or second roller comprises one or more protrusions on the roller face.

3. The apparatus of claim 2 , wherein the protrusions are one of spikes, teeth, screw threads, grooves, abrasive particles, mesas, beads, bristles and a combination thereof to move the lofty porous network at a high speed between about 100 and 600 m/min with minimal crushing.

4. The apparatus of claim 1 , further comprising:
a garniture unit to form the lofty porous network into a filter rod before the wrapping unit; and
an airjet unit to move the lofty porous network of charge retaining polymer fibers to the garniture unit,
wherein the charging unit charges the fibers before or after the garniture unit or the cutting unit.

5. The apparatus of claim 4 , wherein:
(a) the filter rod is cut into lengths before charging one or more fibers of the charge retaining polymer;
(b) the filter rod is cut into lengths and each cut filter rod is attached to a tobacco rod before charging the one or more fibers of charge retaining polymer;
(c) the filter rod is cut into lengths and each cut filter rod is joined with at least one other filter section before charging the one or more fibers of charge retaining polymer; or
(d) the filter rod is cut into lengths, each cut filter rod is joined with at least one other filter section and each joined filter rod is attached to a tobacco rod before charging the one or more fibers of charge retaining polymer.

6. The apparatus of claim 1 , further comprising a cigarette assembly unit to join segments of the wrapped filter rod to one or more tobacco rods, wherein the charging unit charges the charge retaining polymer fibers before or after the cigarette assembly unit.

7. The apparatus of claim 6 , wherein the lofty porous network is arranged downstream of a sorbent including smoke entrainable sorbent particles in the filter wrap to form a composite filter.

8. The apparatus of claim 1 , wherein the charge retaining polymer fibers are selected from the group consisting of a polyethylene, polypropylene, polyvinylidene difluoride, polytetrafluoroethylene, nylon, polyester, polyamide and combinations thereof.

9. The apparatus of claim 1 , wherein the lofty porous network is shaped into a tubular structure, the tubular structure is wrapped with the filter wrap, wherein a trailing end of the filter wrap overlaps a leading edge of the filter wrap wrapped on the tubular structure, and adhesive is applied where the filter wrap overlaps upon itself.

10. The apparatus of claim 1 , wherein the charging unit charges one or more fibers of the charge retaining polymer by tribo-electrification charging, corona charging, electron beam charging, ion beam charging, radiation charging, boundary charging and combinations thereof.

11. The apparatus of claim 1 , wherein one or more fibers of the charge retaining polymer are formed into a lofty porous network by at least one of:
(a) gathering the one or more fibers in a bundle of randomly oriented fibers;
(b) gathering the one or more fibers in a bundle of randomly oriented fibers and one of mechanically bonding, needle punching, hydroentangling, chemically bonding, bonding with adhesives, bonding with latex resin, bonding with hot melt adhesive, thermally bonding, partial melt bonding of fibers, bonding on a heated calender roll, bonding newly formed fibers while still hot and a combination thereof to form the lofty porous network;
(c) gathering the fibers in a bundle of axially oriented fibers;
(d) adding mediating filter fibers;
(e) adding mediating filter fibers which are woven or non-woven fibers of polyester, cellulose acetate or a combination thereof;
(f) adding mediating filter fibers wherein the lofty porous network comprises one of a continuous woven media, a continuous non-woven media, and a combination thereof;
(g) crimping to form a charge retaining tow band of the lofty porous network.

12. The apparatus of claim 1 , wherein the lofty porous network comprises a continuous woven media, a continuous non-woven media, or combination thereof.

13. The apparatus of claim 1 , further comprising a slitting unit to slit the lofty porous network is slit into a desired width, wherein a tow band in a filter rod forming unit is replaced with the lofty porous network having the desired width.

14. The apparatus of claim 1 , wherein the cutting unit cuts the lofty porous network into cylindrical segments; and
the segments of lofty porous network are supplied to a cigarette filter combiner unit wherein the cylindrical segments of porous network are assembled as sections in a cigarette filter.

15. The apparatus of claim 1 , further comprising:
a tool that:
threads through the cylindrical tube;
hooks the lofty porous network; and
moves the lofty porous network into the cylindrical tube and fills the cylindrical tube with the lofty porous network.

16. The apparatus of claim 1 , wherein 2-up plugs of filter material are placed in spaced apart relationship to form a 4-up filter assembly;
plugs including the lofty porous network are placed between the 2-up plugs such that cavities are formed at upstream and downstream ends of every other 2-up plug;
a sorbent including smoke entrainable sorbent particles is placed in the cavities; and
the 4-up filter assembly is cut centrally to form 2-up filter assemblies.

17. The apparatus of claim 16 , wherein a tobacco rod is attached to each end of the 2-up filter assemblies to make a smoking article.

18. The apparatus of claim 17 , wherein said 2-up filter assemblies are cut centrally to form complete cigarettes.

19. An apparatus for manufacturing a filter assembly for a smoking article comprising:
a source of lofty porous network of charge retaining polymer fibers for forming into a filter rod having a pressure drop;
first and second rollers to move the lofty porous network through a gap defined between faces of the first and second rollers to a wrapping unit, wherein the first and second rollers move the lofty porous network through the gap without substantially crushing the lofty porous network;
a wrapping unit to surround the lofty porous network with a filter wrap to form the filter rod;
a charging unit to charge the charge retaining polymer fibers before or after passing the first and second rollers or the wrapping unit; and
a slitting unit to slit the lofty porous network into a desired width, wherein a tow band in a filter rod forming unit is replaced with the lofty porous network having the desired width

Assignees

• Philip Morris Usa Inc

Inventors

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

Classifications

• A24D3/063

  of the fibers · CPC title

• A24D3/02 Primary

  Manufacture of tobacco smoke filters · CPC title

• A24D3/163

  Carbon · CPC title

• A24D3/04

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

• A24D3/0204

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