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
• • 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
  • A24D1/00—Cigars; Cigarettes
  • A24D1/04—Cigars; Cigarettes with mouthpieces or filter-tips
  • A24D1/045—Cigars; Cigarettes with mouthpieces or filter-tips with smoke filter means
• • 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
  • A24D3/0295—Process control means
• • 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
• • 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
  • A24D3/06—Use of materials for tobacco smoke filters
  • A24D3/067—Use of materials for tobacco smoke filters characterised by functional properties

Definitions

• the present invention relates to a filter for a smoking article such as a cigarette.
• Smoke from the combustion of smoking articles is made up of gaseous components and particulate matter, which is commonly referred to as "tar".
• tar gaseous components and particulate matter
• Various types of filter constructions are known in the art for removing undesirable components from the smoke as the consumer draws on the smoking article.
• filter arrangements for smoking articles including composite filters wherein the filter comprises a plurality of separate filter sections with different filtering capacities, and filters comprising different materials such as cellulose acetate and charcoal particles.
• the most common method of introducing ventilating air is by the incorporation of holes in the smoking article filter.
• This approach to reducing the concentration of undesirable components has several associated advantages.
• the smoker continues to receive the desired components and associated taste effects of the smoke.
• the cooler ambient air lowers the temperature of the smoke entering the mouth and throat, producing a more pleasant and agreeable smoking effect.
• the most common method of p ⁇ oviding for the entry of ventilating air into the smoking article is by the provision of small ventilation holes in the form of perforations or conduits through the outer wall of the smoking article.
• the flow rate of air through these ventilation holes into the smoking article is not a linear function of the strength of the draw.
• the proportion of air entering the smoking article via these ventilation holes is reduced as compared with the proportion of smoke from the combustion of the smoking article.
• This phenomenon hereinafter referred to as "the restricted orifice effect" is a consequence of the ventilation holes having a small diameter, typically of the order of less than lmm.
• the restricted orifice effect can be overcome by increasing the diameter of the ventilation holes.
• smoke will undesirably escape through these holes.
• the strength of draw that the consumer is required to impart will be reduced to the detriment of the smoking experience. It is therefore not a simple matter to construct a smoking article having a filter which is not subject to the restricted orifice effect, especially in the case of filters which are required to give a high level of ventilation.
• a filter for use in conjunction with a smoking article, the filter comprising first and second filter passageways operable to impart different filtration efficiencies.
• the filter is arranged so that the amount of smoke passing through one of the passageways relative to the other passageway is controlled by the restricted orifice effect. As the draw is increased, the level of smoke filtration may be increased.
• the restricted orifice effect may be provided by a plurality of holes.
• the holes may be the only means by which smoke is able to pass between the first and second filter passageways.
• the diameter of the holes may be sufficiently small so that with increased dtaw the amount of smoke passing through the holes is increasingly restricted.
• the holes may be between 0.01mm and 2mm in diameter, preferably the holes may be between 0.1mm and lmm in diameter.
• At least one of the passageways may comprise material capable of filtering smoke.
• One of the passageways may comprise a void. Both passageways may comprise material capable of filtering smoke, the first passageway having a lower capacity to filter smoke than the second passageway.
• the amount of smoke that is drawn via the first passageway may be limited by the restricted orifice effect and excess smoke is thus drawn via the second passageway.
• the filter may be ventilated, and this ventilation may be by means of deep vents. Alternatively, the filter may not be ventilated.
• the filter may comprise a plurality of longitudinally abutted filter sections and at least one of these filter sections may be an annular filter section.
• the smoking article to which the filter may be attached may be a cigarette.
• a smoking article comprising a filter and a rod of smokable material.
• Figure 1 is a schematic sectional side elevation view, not to scale, of the filter of an individual filter cigarette according to a first embodiment of the invention
• Figure Ia indicates the route taken by smoke drawn with a low strength through the filter of Figure 1 ,
• Figure Ib indicates the route taken by smoke drawn with a high strength through the filter of Figure 1,
• Figure 2 is a schematic sectional side elevation view, not to scale, of the filter of an individual filter cigarette according to a second embodiment of the invention
• Figure 3 is a schematic sectional side elevation view, not to scale, of an individual filter cigarette according to a third embodiment of the invention.
• Figure 4 is a schematic sectional side elevation view, not to scale, of an individual filter cigarette according to a fourth embodiment of the invention.
• Described herein is a filter for a smoking article which is arranged to utilise the restricted orifice effect to manipulate the passage of smoke and the level of smoke filtration.
• high resistance section is intended to refer to a section of material possessing a high capacity to resist the passage of smoke. This material is also capable of efficiently filtering the undesirable components from smoke, for example, by virtue of having a high density.
• high resistance section high filtration efficiency material
• high resistance material high resistance material
• low resistance section low filtration efficiency material
• low resistance material low resistance material and similar terms are used to refer to a section of material (or a void) possessing a low (or absent) capacity to resist the passage of smoke and a low (or absent) efficiency for filtering smoke
• high or “higher” and “low” or “lower” are intended to reflect the density, resistance, or filtration efficiency of the materials relative to one another; that is, the high resistance section simply has a higher resistance than the low resistance section, although in fact it may possess a low capacity to resist smoke in comparison to other filter materials known in the art.
• the low resistance section may actually possess a relatively high absolute capacity to resist smoke.
• FIG. 1 One embodiment of a smoking article incorporating a filter is shown in Figure 1 in which the smoking article is a cigarette comprising a rod of smokable material 1 (shown partially) and a filter 2.
• the filter comprises filter material 3 which is composed of a high resistance material (shaded).
• the filter is composed of a first section of filter material 3a and a second section of filter material 3b, the two sections being arranged in a longitudinally abutting relationship.
• the section of filter material 3a at the distal end 4 of the filter (away from the mouth end) has substantially the same diameter as the rod of smokable material 1. This is to ensure that all of the smoke drawn along the rod of smokable material 1 enters the filter material 3a.
• the section of filter material 3b at the mouth proximal end 5 of the filter has a reduced diameter and thus a cavity 6 exists between the filter material 3 and the tipping paper 9 which circumscribes the filter 2 of the smoking article.
• This cavity 6 forms a low resistance section.
• the length of this cavity 6 may be equivalent to 10 — 90% of the total length of the filter .2.
• the cavity is 20 - 80% of the total length of the filter.
• the cavity is 30 — 70% of the total length of the filter. More preferably the cavity is 40 — 60% of the total length of the filter.
• the cavity is most preferably 50% of the total length of the filter.
• the mouth proximal end filter section 3b is circumscribed with non-porous phigwrap 7, and a non-porous annular ring member 27 separates the distal end filter section 3a and the cavity 6.
• This annular ring 27 is non-porous with the exception of a series of small perforations 8.
• the perforations 8 are preferably between 0.01mm and 2mm in diameter, more preferably the perforations are between 0.1mm and lmm in diameter.
• smoke is drawn into the mouth from the filter material 3 (the high resistance section) from a first passageway I that is defined within the tubular plug wrap 7 and also via the cavity 6 (the low resistance section) which provides a concentric, second passageway II.
• Smoke passing to the user's mouth along the first passageway I undergoes a greater amount of filtration than smoke that passes to the mouth through the second passageway II.
• Figure Ia illustrates the situation of the smoker drawing on the smoking article with a low strength of draw, i.e. low negative pressure created by the user sucking on the filter.
• smoke is drawn through the filter material 3 along the first passageway I within the tubular plug wrap 7. Additionally, some smoke is drawn from the filter material 3 through the perforations 8 and into the cavity 6 as result of negative pressure produced by drawing on the mouthpiece.
• the smoke is subject to a lower level of filtration than smoke that reaches the user along the first passageway.
• the restricted orifice effect imposes a limit on the amount of smoke that is able to pass through the perforations 8 and enter the second passageway that extends through the cavity 6.
• the remaining smoke is thus drawn into the mouth though the first passageway described above which exclusively comprises the high resistance filter material 3.
• the proportion of smoke that passes along the first passageway as compared with the second passageway increases with increasing draw and thus overall, the smoke drawn by the user is subject to an increased level of filtration with increasing draw.
• a means of supporting the tipping paper 9 at the proximal end 5 of the filter material 3 is provided.
• a band of corrugated paper 10 encapsulates a portion of the length of the mouth proximal section of filter material 3b and is arranged so that a series of substantially longitudinal channels 11 are formed.
• the outermost circumference of the corrugated wrapper 10 is substantially the same as the circumference of both the tobacco rod 1 and the distal end section of filter material 3a.
• the low resistance section is not in the form of a single circumferential cavity, but instead a plurality of low resistance sections may exist.
• An example of such an arrangement is shown in Figure 2, in which the filter material 3 is shaped to provide multiple grooves or channels 28.
• smoke is only able to pass from the filter material (the high resistance section) to the grooves (the low resistance sections) via a series of small holes 29 in a non-porous plug wrap 30 that provides an otherwise non-porous interface between the sections of high and low resistance.
• the restricted orifice effect imposes a limit on the rate at which smoke may pass from the high resistance section to the low resistance section when the user draws on the smoking article.
• the low resistance section is not peripheral to the high resistance section, but is encapsulated by it.
• the high resistance section is a cylindrical section of filter material 12, extending the entire length of the filter 13, and having a diameter substantially the same as the diameter of the rod of smokable material 14.
• the low resistance section is a conical-shaped cavity 15 cut into the mouth end of the filter material 12.
• the length of this cavity 15 may be equivalent to 10 - 90% of the total length of the filter 13.
• the cavity is 20 — 80% of the total length of the filter.
• the cavity is 30 — 70% of the total length of the filter. More preferably the cavity is 40 - 60% of the total length of the filter.
• the cavity is most preferably 50% of the total length of the filter.
• the inner surface of the conic cavity is covered in a non-porous coating 16. This may be achieved, for example, by inserting a pre-formed cone, of a non-porous material such as plastic that has been pre-perforated with holes, directly into the end of the filter material.
• the non-porous lining 16 of the cavity is characterised by one or more bands of perforations 17.
• the perforations 17 are preferably between 0.01mm and 2mm in diameter, more preferably the perforations are between 0.1mm and lmm in diameter.
• the cavity 15 in the mouth end of the filter is not conic but may be substantially cylindrical, or indeed any other suitable shape.
• the restricted orifice effect is harnessed to limit the passage of smoke from low resistance section to high resistance section.
• FIG. 4 Another embodiment is shown in Figure 4 in which the filter arrangement shown in Figure 1 is abutted to the rod of smokable material in a longitudinally reversed orientation.
• the mouth distal end of the filter material 18 (the high resistance section) has a diameter which is less than that of the rod of smokable material 19.
• a cavity 20 (low resistance section) exists between the filter material 18 and the tipping paper 21. Smoke may therefore become drawn from the rod of smokable material 19 into either high resistance section 18 ot low resistance section 20.
• the filter material 18 is covered in a non-porous plug wrap 22.
• an annular ring 28 is situated which is non-porous except for a series of small perforations 23.
• the perforations 23 are preferably between 0.01mm and 2mm in diameter, more preferably the perforations are between 0.1mm and lmm in diameter.
• a means of supporting the tipping paper 21 about the cavity 20 comprising a band of corrugated paper 24 that encapsulates a portion of the length of the filter material 18 and arranged so that a series of substantially longitudinal channels 25 are formed.
• the outermost circumference of the corrugated wrapper 24 is substantially the same as the circumference of the rod of smokable material 19.
• the low resistance section need not be a cavity but can comprise a second filter material which has a lower resistance than the filter material comprising the high resistance section.
• the smoke is subject to an increased total level of filtration as compared with an arrangement where the low resistance section is simply a cavity.
• the entire filter can be encapsulated by non-porous tipping paper that may be provided with a circumferential band of perforations which permit diluting air to pass into the filter material comprising the high resistance section.
• tipping paper may be perforated before (p re-perforated; PP) or after cigarette construction, and perforations may be introduced via an array of pins or using an on machine laser (OML) system.
• OML on machine laser
• the perforations in the tipping paper and/ or the plug wrap of the filter are manufactured using PP or OML technology and consequently do not penetrate substantially into the filter material comprising the high resistance section.
• the tipping paper perforations comprise deep vents, which may be manufactured by DVOML, via alternative suitable methods, and which extend substantially towards the diametric centre of the filter material comprising the high resistance section.
• deep vents diluting air is drawn into the centre of the filter and this has the effect of modifying the flow of smoke drawn from the rod of smokable material.
• the perforations 26 comprise deep vents
• air drawn through these holes will enter the filter material 3 close to the diametric centre of the filter material. This will have the effect of concentrating the smoke drawn from the rod of smokable material 1 into a diametrically peripheral zone of the filter material 3.
• the mixture of smoke and ventilating air exiting the filter material via the perforations 8 therefore contains a higher proportion of smoke than is the case when the perforations 26 only penetrate the tipping paper 9.
• the filter need not be ventilated, or may be ventilated by alternative means, such as via an area of porous tipping paper and plug wrap.
• the filter material comprising the sections of high and/ or low resistance comprises a plurality of abutted filter sections made of similar or different materials.
• Each of the filter sections may consist of one or a combination of cellulose acetate, polypropylene, paper or any other suitable material.
• the filter section(s) may alternatively or additionally comprise carbonaceous material, for example, activated charcoal, a resin material such as amberlite or duolite, and/ or catalytic material.
• one or more of the filter sections may comprise an annular filter section.
• the annulus may be a cavity or may be composed of filter material with a lower resistance, thus the annulus comprises the low resistance section.
• the filter is constructed from a plurality of filter sections and one or more annular sections are used wherein the annulus comprises the high resistance section.
• the filter material may be shaped by heat moulding, embossing, crimping or any other suitable method.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Cigarettes, Filters, And Manufacturing Of Filters (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Families Citing this family (10)

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• 2008
  • 2008-07-24 GB GBGB0813567.5A patent/GB0813567D0/en not_active Ceased
• 2009
  • 2009-07-23 AU AU2009275329A patent/AU2009275329B2/en not_active Expired - Fee Related
  • 2009-07-23 CN CN2009801288545A patent/CN102105073A/zh active Pending
  • 2009-07-23 BR BRPI0916539A patent/BRPI0916539A2/pt not_active IP Right Cessation
  • 2009-07-23 AR ARP090102811A patent/AR074708A1/es not_active Application Discontinuation
  • 2009-07-23 RU RU2011106362/12A patent/RU2011106362A/ru unknown
  • 2009-07-23 US US13/055,437 patent/US20110186063A1/en not_active Abandoned
  • 2009-07-23 EP EP09785382A patent/EP2328432A1/en not_active Withdrawn
  • 2009-07-23 WO PCT/GB2009/050908 patent/WO2010010397A1/en active Application Filing
  • 2009-07-23 MX MX2011000453A patent/MX2011000453A/es not_active Application Discontinuation
  • 2009-07-23 UA UAA201101829A patent/UA100435C2/ru unknown
  • 2009-07-23 KR KR1020117004364A patent/KR20110038700A/ko not_active Application Discontinuation
  • 2009-07-23 JP JP2011519244A patent/JP2011528900A/ja not_active Ceased
  • 2009-07-23 CA CA2731233A patent/CA2731233A1/en not_active Abandoned
• 2011
  • 2011-01-13 CL CL2011000081A patent/CL2011000081A1/es unknown
  • 2011-01-21 ZA ZA2011/00572A patent/ZA201100572B/en unknown

Non-Patent Citations (1)

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