Classifications

• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
  • A24D3/04—Tobacco smoke filters characterised by their shape or structure
  • A24D3/043—Tobacco smoke filters characterised by their shape or structure with ventilation means, e.g. air dilution
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
  • A24D3/02—Manufacture of tobacco smoke filters
  • A24D3/0275—Manufacture of tobacco smoke filters for filters with special features
  • A24D3/0279—Manufacture of tobacco smoke filters for filters with special features with tubes
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
  • A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
  • A24D3/04—Tobacco smoke filters characterised by their shape or structure
  • A24D3/045—Tobacco smoke filters characterised by their shape or structure with smoke acceleration means, e.g. impact-filters

Definitions

• the present invention relates to an improved filter for smoking articles and to smoking articles incorporating such a filter. More particularly, it relates to a filter for a cigarette.
• the bandwidth of a smoking article is a measurement ratio between the tar delivery of a cigarette smoked under testing conditions of the International Standards Organization (ISO) versus the tar delivery of the same cigarette smoked in other, usually more intense conditions.
• ISO International Standards Organization
• ISO testing conditions involve the smoking of a cigarette wherein the puff volume is 35 mL, the puff duration is two seconds, and the interval between puffs is 60 seconds. More intense smoking conditions may include an increase in puff volume, an increase in puff duration, a decrease in time between puffs, or some combination of these changes.
• a lower bandwidth corresponds to a decreased variance in the amount of smoke constituents delivered by a cigarette when smoked under ISO conditions and by the same cigarette smoked under more intense smoking conditions.
• the puff profile of a cigarette is the delivery of smoke constituents per puff recorded against puff number.
• a puff profile having reduced variance between puffs, i.e., a relatively flat puff profile, is one in which the delivery of smoke constituents is more consistent in each puff during smoking.
• TPM Total Particulate Matter
• This increase in particulate matter in later puffs is caused by a number of factors, including a decrease in filtration efficiency of the tobacco rod, a decreased level of ventilation of the tobacco rod through the cigarette paper — both of which result from the length of the tobacco rod being reduced during smoking — and an increased smoke particulate phase constituent potential of the tobacco rod due to the deposition of smoke particulate phase constituents from the earlier puffs onto the rod.
• the ratio of smoke constituents between the first to last puffs in a cigarette varies based on a number of product design characteristics, including the total smoke constituent yield for that product. Typically, ratios of between 2 and 4 for "full flavor” products (having more thanlO mg TPM), between 3 and 5 for “lights” (5-10mg TPM), and between 4 and 6 for “ultra lights” (less than 5mg TPM) are achieved under ISO machine smoking conditions. The higher levels of ventilation used in the "light” and “ultra light” products cause the ratio to increase even as the products' smoke constituent yields decrease.
• the invention comprises a filter for smoking articles having at least two different sections.
• a first section comprises an inner area and a surrounding area, the inner area and the surrounding area comprising a smoke flow path and an area of relatively smoke impervious material.
• the relatively smoke impervious material has increased flow resistance when compared to the smoke flow resistance of the smoke flow path.
• the smoke flow path and the relatively smoke impervious material are arranged in a core and annulus configuration, with the smoke flow path forming the core.
• the smoke flow path forms the annulus and the relatively smoke impervious material forms the core of the first section.
• the second section comprises a smoke impaction zone in axial alignment with the smoke flow path of the first section.
• the second section of the filter may comprise a core comprising high pressure drop filter material and an annulus comprising a lower pressure drop material than the core or vice versa.
• the first and second sections are spaced apart from one another by means of an intervening gap.
• the filter is designed such that the smoke flow path of the first section is axially aligned with the core of the second section.
• the core of the second section is made of high pressure drop filter material when compared to the filter material of the annulus of the second section.
• smoke exits the smoke flow path of the first section such that a large portion of the smoke — especially the heavier smoke constituents — impact on the high pressure drop core of the second section.
• a plug of relatively smoke impervious material may be located in the second section in axial alignment with the exit of the smoke flow path of the first section such that a large portion of the smoke — especially the heavier smoke constituents — impact on the plug of relatively smoke impervious material on the second section. Impaction filtration occurs when smoke particles hit a material and are retained by it, thus in the embodiments described above, smoke components impacting on the smoke impaction zone of the second section will be retained thereby.
• the invention further comprises ventilation holes circumscribing the second section or circumscribing the space or gap between the first and second section.
• Ventilation may be provided by means known to the skilled artisan, such as laser or mechanical perforation.
• the filter may further comprise additional sections.
• the additional filter sections may comprise conventional filtration material such as, for example, cellulose acetate, polypropylene or paper.
• the additional filter sections may alternatively or additionally comprise carbonaceous material for example, activated charcoal, resin material for example, amberlite, duolite or the like, and/or catalytic material.
• the present invention further provides a smoking article comprising a rod of smokable material, a wrapper circumscribing the rod of smokable material, and a filter according to the present invention attached to the rod of smokable material.
• the first section of the filter according to the invention is preferably adjacent to the rod of smokable material of the smoking article at a first end and is spaced from the second section of the filter at an opposed end.
• the filter of the present invention and the rod of smokable material may be interattached by any means known in the art such as, for example, a tipping wrapper.
• the tipping wrapper may circumscribe the filter along its length and overlap with the rod of smokable material.
• the tipping wrapper may be attached to the wrapper of the rod of smokable material by conventional means, for example, by adhesive.
• the filter and the rod of smokable material are preferably in co-axial alignment with one another.
• the filter may comprise one or more additional filter segments.
• the additional filter segment(s) may be located between the rod of smokable material and the first filter section, and/or may be located at the mouth end of the second filter section.
• Fig. 1 is a perspective view of a cigarette with selected portions shown in cut-away; and Fig. 2 is a cross-section of an embodiment of the cigarette shown in Fig. 1;
• Fig. 3 is a cross-section of another embodiment of the cigarette shown in Fig. 1;
• Fig. 4 is a perspective view of another embodiment of the cigarette shown in Fig.l ;
• Fig. 5 is a perspective view of yet another embodiment of the cigarette shown in Fig. 1;
• Fig. 6 is a graphical representation of the effectiveness of several embodiments of the invention in reducing total particulate matter
• Fig. 7 is a graphical representation of the effectiveness of one embodiment of the invention in reducing bandwidth.
• the invention comprises a cigarette filter 1 and a cigarette 3 designed to reduce the delivery bandwidth of a cigarette in use.
• the cigarette 3 comprises a tobacco section 18 and a filter 1.
• the filter 1 comprises a first section 2 comprising an inner area 4 and a first surrounding area 6.
• the first section 2 is on the end of the cigarette 3 nearest to the tobacco section 18.
• the diameter of the inner area 4 is preferably between 0.5 and 3.0 mm and between 5 and 10 mm in length. It will be understood that the length of the smoke flow path will be determined by the length of the filter; the length of the smoke flow path of the first section, however, will be equal to the length of the first section.
• the inner area 4 and the surrounding area 6 should comprise a smoke flow path and an area that is relatively impervious to smoke.
• the inner area 4 is the smoke flow path and the surrounding area 6 is impervious to smoke.
• the smoke travels through the smoke flow path 4 and exits the cigarette at a high velocity.
• the smoke flow path can be formed by the surrounding area 6 with the inner area 4 being formed of smoke impervious material.
• the smoke flow path 4 can take on a number of different embodiments.
• the smoke flow path 4 can comprise a tube 30, as shown in Fig. 2, or a lower pressure drop material 40 — such as cellulose acetate — than that of the surrounding area 6, as shown in Fig. 3.
• the filter 1 further comprises an axially aligned second section 8 comprising a core 10 circumscribed by an a ⁇ nulus 12.
• the inner core 10 of the second section 8 is axially aligned with the inner area 4 of the first section 2.
• the filter 1 further comprises a space or gap 14 situated between the first section 2 and the second section 8.
• the gap 14 can be in the range of 0.0001 mm to 4 mm in length, but in various embodiments of the invention may be in the range of 0.1 - 3.8 mm, or in the range of 0.5 - 3.5 mm, or in the range of 1 - 3 mm, or in the range of 1.5 - 2.5 mm, and in one particular embodiment of the invention is about 2 mm. If the gap is too wide, the heavier smoke constituents will diffuse within the gap 14 between the first and second filter sections before impacting the second section 8, which would negatively impact the performance of the filter 1. Along with the rest of the filter 1, the gap 14 is wrapped in plug wrap and attached to the rest of the cigarette with conventional tipping paper.
• Either the core 10 or the annulus 12 of the second section 8 must form an impaction zone of relatively smoke impervious material. If the smoke flow path in the first section is the inner area 4, then the impaction zone of the second section 8 will be in the region of the core 10.
• the smoke impaction section can extend along the whole length of the second section 8, as shown in Figs. 1-3, or as shown in Figure 4, it can be a small disc 32 of smoke impervious material attached to the end of a regular filter section 34. In the embodiment shown in Figure 4, smoke would diffuse behind the smoke impervious material, but the heavier smoke constituents would first be removed by their impaction on the small disc 32.
• the impaction zone of the second section 8 will be in the region of the annulus 12. As shown in Figs. 1-3, this can be an annulus 12 of relatively impervious material along the whole length of the second section 8, or it could be an annular disc 36 of the same material affixed to the end of the regular filter section 34, as shown in Fig. 5.
• the diameter of the outer annulus 12 is preferably 40% of the total diameter of the filter 1, but the filter will function properly, however, as long as the core 10 is wider than the exit diameter of the smoke flow path of the first section 2.
• the annulus 12 acts as the impaction zone, its width should be bigger than that of the smoke flow path formed by the surrounding area 6.
• the length of the second section 8 can be any length to make up the desired total length of the filter 1, and it is usually about 5 to 50 mm.
• the second section 8 is generally the mouth end of the cigarette filter.
• the filter 1 further comprises ventilation holes 20, which can be positioned in either the second section 8 or the gap 14.
• the filter 1 reduces the delivery bandwidth in two different ways. Firstly, when the cigarette is being smoked, the smoke passes through the smoke flow path of the first section 2 and enters the gap 14 at high velocity. Due to the short distance between the filter sections 2, 8 and the high velocity at which the smoke travels, most of the smoke particles do not disperse before impacting and sticking on the high pressure drop material of the second section 8 opposite the smoke flow path of the first section 2. The heavier smoke particles disperse less than the lighter particles, which leads to less total particulate matter leaving the cigarette. The harder the puff on the cigarette, the less dispersion of the smoke occurs, and the more filtering that takes place.
• the second way that bandwidth is reduced involves the use of ventilation holes.
• the tube 4 in the first section 2 progressively fills with particulate smoke constituents, which increases the resistance to smoke flowing through the tube 4. This increases the pressure drop through the first section 2, which causes more diluting air to be pulled through the ventilation holes 20 when the smoker inhales.
• the diluting air enters the gap 14 or the second section 8 through ventilation holes 20 circumscribing the second section 8 or the gap 14. This further concentrates the smoke in the middle of the gap 14, thereby causing most of the smoke to impact the core 10, which in the preferred embodiment comprises the impaction area of the second section 8.
• Example A and B the first and second sections were 11 and 14 mm in length, respectively, and there was a 2 mm gap between the sections.
• Example C and D the first section was 11 mm long and the second section was 16 mm long, and the gap between the two sections was 0.001 mm.
• AU of Examples A, B, C, and D had a tube in the first section with an internal diameter of 2 mm.
• the annulus of the second section was made of high pressure drop material, whereas in Examples
• the annulus of the second section was made of lower pressure drop material.
• Table 2 and Fig. 7 show the reduction in bandwidth that occurs when one embodiment of the invention — Example D — is smoked under various conditions. The more extreme the conditions, the better Example D performs compared to the control cigarette. At ISO conditions (puff volume of 35 mL, puff duration of 2 seconds, puff interval of 60 seconds), the difference between the amounts of particulate matter is relatively small. But as the overall intensity of the puffs increases, the effectiveness of the filter of the invention improves, as is demonstrated by the large difference in TPM between the control and Example D. TABLE 2 -Delivery of TPM at ISO and Other Conditions
• the various embodiments of the invention have a measurable beneficial effect on decreasing the bandwidth, decreasing the TPM, and smoothing out the puff profile of a cigarette as it is smoked. It is apparent that the location of the high pressure drop material and the width of the gap will modify the performance of the invention while still using concepts of the present invention. Such variations are deemed to fall within the bounds of the present application.

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• Cigarettes, Filters, And Manufacturing Of Filters (AREA)

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Publications (1)

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ID=36141949

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Cited By (17)

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Citations (7)

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• 2006
  • 2006-02-16 GB GBGB0603126.4A patent/GB0603126D0/en not_active Ceased
• 2007
  • 2007-01-19 WO PCT/GB2007/000155 patent/WO2007093757A1/en active Search and Examination
  • 2007-01-19 UA UAA200811171A patent/UA91407C2/ru unknown
  • 2007-01-19 AT AT07704936T patent/ATE516716T1/de not_active IP Right Cessation
  • 2007-01-19 PL PL07704936T patent/PL1983852T3/pl unknown
  • 2007-01-19 BR BRPI0707756-4A patent/BRPI0707756A2/pt not_active IP Right Cessation
  • 2007-01-19 AU AU2007216341A patent/AU2007216341B2/en not_active Ceased
  • 2007-01-19 ES ES07704936T patent/ES2370008T3/es active Active
  • 2007-01-19 MY MYPI20083016A patent/MY159363A/en unknown
  • 2007-01-19 JP JP2008554833A patent/JP2009526540A/ja active Pending
  • 2007-01-19 EP EP07704936A patent/EP1983852B1/en not_active Not-in-force
  • 2007-01-19 RU RU2008136759/21A patent/RU2421110C2/ru not_active IP Right Cessation
  • 2007-01-19 MX MX2008010505A patent/MX2008010505A/es active IP Right Grant
  • 2007-01-19 CA CA002642521A patent/CA2642521A1/en not_active Abandoned
  • 2007-01-19 US US12/279,535 patent/US20090314303A1/en not_active Abandoned
  • 2007-01-19 KR KR1020087022579A patent/KR20080094731A/ko not_active Application Discontinuation
  • 2007-01-19 CN CN2007800054048A patent/CN101384185B/zh not_active Expired - Fee Related
  • 2007-02-02 TW TW096103895A patent/TWI399181B/zh not_active IP Right Cessation
  • 2007-02-14 AR ARP070100640A patent/AR059453A1/es not_active Application Discontinuation
• 2008
  • 2008-08-05 ZA ZA200806787A patent/ZA200806787B/xx unknown

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