WO2000000047A1

WO2000000047A1 - Low delivery cigarette and filter

Info

Publication number: WO2000000047A1
Application number: PCT/US1999/014791
Authority: WO
Inventors: Charles R. Lambert, Jr.; Martin T. Garthaffner; Donald E. Laslie; Duane C. Wilder
Original assignee: Philip Morris Products SA; PHILIP MORRIS PRODUCTS Inc
Current assignee: Philip Morris Products SA; PHILIP MORRIS PRODUCTS Inc
Priority date: 1998-06-30
Filing date: 1999-06-30
Publication date: 2000-01-06
Anticipated expiration: 2000-12-30
Also published as: AU4847399A; WO2000000047A9

Abstract

A cigarette comprising a tobacco rod (3) and filter tipping (4), the filter tipping (4) including a band of laser perforations at a downstream location (48) and a second band of perforations at an upstream location (42), the second band (42) comprising an outer band of laser perforations in a tipping paper (50) in a superposed relation with a zone of plug perforations at the upstream location (52).

Description

LOW DELIVERY CIGARETTE AND FILTER

Field of Invention

The present invention relates to filter cigarettes, and more particularly, to filter cigarettes having elevated levels of ventilation.

Background of the Invention

Consumer preferences and regulatory pressures have created market movements toward ever higher levels of ventilation in cigarettes.

Ventilation in a cigarette is the dilution of mainstream smoke with air from the surrounding environment. The degree of ventilation is understood to be the proportional part of puff volume which is attributable to air passing through the filter wrapper of the cigarette during a puff. It is typically measured as a percentile of a standard, 1 ,050 cc per minute rate of drawn flow.

Methods of effecting filter dilution have included the selection of a tipping paper having a desired level of permeability, which is typically described in terms of CORESTA units. Perforation of the tipping paper has been used to achieve additional ventilation in many cigarette designs.

One method of establishing perforations employs an on-line laser to burn ventilation holes circumferentially about one or more locations along the filter of cigarettes as the cigarettes pass through the latter portions of a tipping machine. Such arrangements are exemplified by the Hauni Laser System provided in the Max or Max S tipping machines sold by Hauni Maschinenbau of Hamburg, Germany.

Preferably, the on-line laser is of sufficient power and time pulse to effect a pre-determined number of holes, with a capacity to controllably and consistently provide up to 40 to 50% ventilation at typical cigarette manufacturing speeds. To achieve even greater ventilation levels, laser power must be increased or the tipping machine speed must be reduced, so as to provide the lasers sufficient time to burn larger and/or a greater number of holes. However, larger lasers demand greater safety precautions and capital outlay. The alternative, slowing down the machines, is inimical to cigarette manufacturing efficiency and is therefore a very unattractive proposition.

Another method of effecting filter ventilation utilizes pre-perforated plug wrap or in the alternative pin perforated, wrapped filter plugs. Both of these known techniques are difficult to achieve at ventilation levels of 40 or more. Additionally, the pre-perforated technique usually requires employment of a porous plug wrap, which itself adds cost and presents additional operational problems. Porous plug wraps usually tear more easily than less porous or non-porous types. Also, porous plug wraps tend to expand with a filter plug as its tow cures. Accordingly, it is more difficult to control filter diameter with porous plug wrap. It is also more absorbent of moisture and glue which can exacerbate spotting problems in the final product. Additionally, the acts of pre-perforating a tipping paper and mechanically pin perforating a filter plug removes material at or about the region of perforation such that physical degradation of the tipping paper and/or filter plug may occur if extreme levels of ventilation were attempted with such techniques alone. Objects and Summary of the Invention

Accordingly, an object of the present invention is to provide a cigarette and cigarette filter providing extreme ventilation percentiles without creating difficulties or compromising product integrity. Another object of the present invention is to provide a novel cigarette and cigarette filter construction which achieves high ventilation levels, above 60%, precisely and at high cigarette manufacturing speeds.

Yet another object of the present invention is to achieve a highly ventilated cigarette and cigarette filter which achieves a predominant portion of the total ventilation through the most controllable ventilation technique. Still another object of the present invention is to achieve a novel cigarette and cigarette filter which features extreme ventilation without compromising structural integrity of the cigarette.

These and other objects of the present invention are achieved by providing a cigarette having a circumferential row of laser generated ventilation holes at a downstream location along its filter, together with a ventilation arrangement at an upstream location along its filter comprising a pin perforated filter plug enwrapped in a tipping paper having a region of pre-perforations superposing the pin perforated portion of the filter plug. The laser ventilation holes are configured to provide a majority portion of the total ventilation so that the contribution of ventilation at the upstream location is less than that of the downstream location. The arrangement also improves mixing of the mainstream smoke with the air drawn into the cigarette from the ventilating portions of the filter. By such arrangement, extreme levels of ventilation are achievable

(60 to 95%) using known and readily available manufacturing techniques without significant capital expenditures. The cigarette filter is also manufacturable at currently preferred manufacturing speeds. Brief Description of the Drawing

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the preferred embodiments when considered in conjunction with the accompanying drawing, wherein:

Fig. 1 is a first preferred embodiment of a recessed, dual plug, highly ventilated cigarette shown in cross-section;

Fig. 2 is a partially unraveled perspective view of the cigarette shown in Fig. 1 ; Fig. 3 is a cross-sectional view of a 4-up filter rod used in the construction of the preferred embodiment of the present invention; and

Fig. 4 is a side view of an alternate embodiment of the inventon.

Detailed Description of the Preferred Embodiments

"Upstream" and "downstream" directions as used in the description which follows are considered relative to the direction of mainstream smoke as it is drawn through filter tipping during a draw upon a cigarette.

The preferred embodiment of the present invention provides a cigarette 2 which is configured to deliver upon its smoking a low tar delivery level of between approximately 1 milligram of tar to 5 milligrams, more preferably in the range of approximately 1 milligram to 3 milligrams as measured by established FTC procedures of early 1998 (FTC tar is total particulate matter minus nicotine and water content). In order to do so, air ventilation is provided in the filter tipping 4 at a first, downstream location 32 and at a second upstream location 34 such that dilution levels are achieved at grand total dilution percentile levels of 65-70%, preferably with only a 5% variation amongst a manufactured batch of cigarettes. Such elevated levels of ventilation (and even greater, up to 90%) are achievable with practice of the present invention as exemplified with the details provided in the preferred embodiment as shown in Figs. 1 and 2. The cigarette 2 constructed in accordance with the preferred embodiment of the present invention comprises a tobacco rod 3 and a filter tipping 4. The tobacco rod portion 3 preferably comprises a column of shredded tobacco 7, either blended or a varietal tobacco as is typically found today in commercially available cigarette products. The tobacco rod 3 is wrapped within a paper wrapper 6.

Preferably, the filter tipping 4 comprises a cellulose acetate filter plug 20 that is spaced apart from the free end 22 of the tipping 4 so as to define a recess 24 within the filter tipping 4 adjacent the free end 22. Preferably, a second charcoal-laden filter plug 26 is interposed between the first filter plug 20 and the tobacco rod 3, and the two filter plugs 20 and 26 are combined together with a non-porous mouthpiece paper 36. Preferably, the filter tipping 4 includes a zone of pin perforations 42 at an upstream location 34 along the first, downstream filter plug 20. Preferably, the zone of pin perforations 42 extends 6 to 8 mm, beginning approximately 12 mm from the free end 22 of the filter tipping 4 and extending to a location approximately 18 mm from the free end 22 of the filter tipping 4. Other zone widths might be utilized instead. The pin perforating operation preferably creates a field of irregular perforation holes 28 extending through the mouthpiece paper 36 and the plug wrap 28 of the first filter plug 20.

Preferably, the tipping paper 10 is provided with one or more rows of off-line laser perforations ("microperfs") 50 at a location along that portion of the tipping paper 10 which at least partially superposes the zone of pin perforations 42 on the first plug 20. Each row of off-line laser perforations typically will include approximately thirty (30) to forty (40) perforation holes 50, depending upon the nature of the selected laser pulse. Such can be achieved by pre-perforating the tipping paper at 30 to 50 holes per inch of paper, more preferably at 35-45 holes per inch. Preferably, the band of pin perforations 42 have a band width of approximately 6 to 8 mm which facilitates alignment of the row or rows of laser perforated holes 50 in the tipping paper 10 with the zone of pin perforations 42.

Accordingly, ventilation is communicated from outside the first filter plug 20 to within the first filter plug 20 at the upstream location 34 through the row of off-line laser perforations 50 of the tipping paper 10 and the band of pin perforations 42.

Preferably, each of the filter plugs 20 and 26 are provided with a porous plug wrap 28 and 29 respectively, although in practice of the present invention, non-porous plug wraps might be used in the alternative. The filter plugs 20 and 26 are combined together preferably with the non-porous mouthpiece paper 36 whose elevated basis weight is sufficient for establishing the aforementioned recess 24 at the free end of the tipping 22 with the desired resistance to collapse. Preferably, the mouthpiece paper 36 has a basis weight in the range of 90 to 140 grams per square meter, more preferably in the range of 110 to 130 grams per square meter. Referring now also to Fig. 3, preferably, during manufacturing operations, a succession of the filter plugs 20 and 26 are repetitively combined in a repeated mutual relation within a continuous ribbon of the mouthpiece paper 36 so as to form a continuous rod which includes spaces corresponding to the recesses 24 in the final filter tipping 4. Preferably, the rod is repetitively cut into individual filter rods 43 usually in a four-up configuration as shown in Fig. 3.

Once the plugs 20 and 26 have been combined within the mouthpiece paper 36, the filter assembly undergoes a pin perforation operation at each of the locations 47 corresponding to the downstream location 34 along the first plugs 20, preferably at a perforating station along the filter rod forming operation or preferably after the four-up rod 43 is formed. The tipping machine then executes the step of attaching the combined plugs 20 and 26 to a tobacco rod 3 by axially aligning the filter and tobacco rod components and wrapping same with the tipping paper 10 such that the one or more rows of micro-perforations 50 overlap the respective zone of pin perforations 42.

In the alternative, the second filter plug 26 may be a charcoal-free cellulose acetate plug or made an integral part of the first filter plug 20. Whereas the tipping 4 of preferred embodiment as shown in Fig. 2 comprises a combined charcoal filter, the present invention is workable with a host of alternative plug constructions, including single-plug, plug-space- plug, or any of the various forms of coaxial plugs, whether they are with or without recesses. Additionally, all of the perforations need not be placed about the first filter plug 20.

Preferably, the band of pin perforations 42 are created utilizing technique and machinery used typically in the cigarette industry, as described in U.S. Patent No. 4,665,930 to Arthur et al. Typically such devices and processes move plug assemblies along a transfer path defined by one or more drums while interposing a rack of pins along the transfer path such that the pins impinge upon the filter assemblies.

Preferably, the row(s) of laser per orations 50 provided along the tipping paper 10 is established using known automated techniques such as is taught in U.S. Patent No. 5,341 ,824 to Fletcher et al. Once combined and pin-perforated, the filter assembly is attached to the tobacco rod 3 with the tipping paper 10 in accordance with the established practices in the cigarette manufacturing industry as previously described. Thereupon, the cigarette is passed along an on-line laser system such the system provided in Hauni Max and Hauni Max S tipping machines. Preferably, the power setting and pulse time is set at the on-line laser system so as to establish a 30% to 60% ventilation level with the laser perforated band 46, more preferably in the range of 40 to 60%. Preferably, the band of laser perforations 46 comprises a single row of eight to twenty holes 48, more preferably approximately ten holes, that are burned by laser through the tipping paper 10, the mouthpiece paper 36 and the plug wrap 28 of the first filter 20. The holes 48 are preferably positioned at approximately 10 millimeters or more from the free end 22 of the filter tipping 4, yet downstream of the pin perforations 42. Fewer or a greater number of laser perforation holes 48 may be employed, depending upon whether a lesser or greater amount of ventilation is desired, or as laser performance limitations may require. However, in the practice of the present invention, the band 46 of laser holes 48 are located at the downstream location 32 closer to the free end 22 of the filter tipping 4 than the row of off-line laser-perforations 50. Preferably, the laser output is adjusted to provide the desired percentile amount of ventilation desired from the row of downstream laser perforations 46, preferably up to 50 percentile points of ventilation. Preferably, the laser perforations 46 are sized such that they provide approximately 60 to 80% of the grand total of ventilation, more preferably at or about 70% of the grand total.

Referring particularly to Fig. 1 , randomly, the row of pre-perforated holes 50 superpose various members of the holes 52 provided along the zone of pin perforation 42 so as to permit draw of ventilating air into that upstream location 34 along the filter tipping 4. A cognizable portion of the holes 50 along the band of pre-perforations 50 in the tipping paper do not coincide with any particular hole 52 of the band of pin perforations 42 and are consequently at least partially occluded. This randomness is acceptable at lower levels of ventilation at region 34 to produce a desired target ventilation in the range of 20 to 40 percentile points of ventilation with acceptable precision. Again, the present invention assures that ventilation at the upstream location 32 is maintained within these lower limits by the downstream placement of the more precisely controlled laser perforations 48 which in effect provide a short circuit between the upstream location 32 and the source of underpressure (the smoker's draw) adjacent the free end 22 of the tipping 4. Preferably, the laser perforation holes 48 are sized so as to provide a predominant fraction of the total target ventilation which in the preferred embodiment is preferably approximately a 50% to 60% ventilation contribution of the laser ventilation holes 50 out of a grand total target ventilation of approximately 65 to 90% ventilation. Not wishing to be bound by theory, the presence and downstream relation of the on-line laser per orations 48 are believed to promote a more even distribution of mainstream smoke across the filter, as opposed to having the mainstream smoke concentrate centrally as it passes through the filter. This transverse dispersion is believed to improve sensorial perceptions during puffs.

For lower deliveries, such as a 1 mg delivery cigarette by way of non- limiting example, the number of on-line laser perforations holes may be increased, preferably to 12, and, as shown in Fig. 4, a second row of laser pre-perforations 50' are added to the tipping paper in superposing relation to the pin perforations 42 so as to establish first and second rows of laser pre-perforations 50, 50'. Such arrangements can achieve elevated levels of ventilation in ranges above 75% ventilation.

It is to be understood that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. For example, laser perforation techniques instead of pin perforation may be employed to establish a zone of plug perforations 42' about the filter plug 20 at a location corresponding to the upstream location 34 (Fig. 3). Various forms of mouthpiece paper might be employed other than what has been specifically described herein. The scope of the invention is indicated by the appended claims rather than by the foregoing descriptions and all changes in variations which fall within the meaning and range of the claims are intended to be embraced therein.

Claims

Claims:

1. A cigarette comprising a tobacco rod and filter tipping, said filter tipping including an upstream location and a downstream location along said filter tipping, said downstream location more proximate to a free end of said filter tipping, said cigarette comprising: a band of laser perforations at said downstream location; a second band of perforations at said upstream location, said second band comprising a row of pre-perforations in a tipping paper and a zone of plug perforations, said row of pre-perforations of said tipping paper at least partially superposing said band of plug perforations; said downstream laser perforations configured to provide a greater amount of ventilation than said second band of perforations at said upstream location.

2. The cigarette as claimed in claim 1 wherein said filter provides a total ventilation in the range of approximately 65-90%; and said ventilation contribution at said downstream location is in the range of approximately 40 to 60%.

3. The cigarette as claimed in claim 1 , wherein said filter tipping comprises a recess portion adjacent said free end, a first filter plug adjacent said recess, a second filter plug interposed between said first filter plug and said tobacco rod, said filter tipping further comprising a mouthpiece paper disposed about said first filter plug and defining said recess, said filter tipping further comprising a tipping paper disposed about said mouthpiece paper, said laser perforations at said downstream location being into said tipping paper, said mouthpiece paper and said first plug, said plug perforations being located about said first filter plug at said upstream location and into said mouthpiece paper and said first filter plug, said row of pre-perforations being through said tipping paper in superposing relation to said plug perforations.

4. The cigarette as claimed in claim 3, wherein said plug perforations are pin perforations, and said pre-perforations comprise a single row of off- line laser perforations.

5. The cigarette as claimed in claim 4, wherein said mouthpiece paper has a basis weight in the range of 90 to 140 grams per square meter.

6. The cigarette as claimed in claim 5, wherein said second filter plug includes particles.

7. The cigarette as claimed in claim 6, wherein said particles include charcoal particles.

8. The cigarette as claimed in claim 3, wherein said plug perforations are pin perforations, and said pre-perforations comprise two rows of off-line laser perforations.

9. The cigarette as claimed in claim 8, wherein said mouthpiece paper has a basis weight in the range of 90 to 140 grams per square meter.

10. The cigarette as claimed in claim 9, wherein said second filter plug includes particles.

11. The cigarette as claimed in claim 10, wherein said particles include charcoal particles.