EP3720306B1

EP3720306B1 - Tobacco smoke filter

Info

Publication number: EP3720306B1
Application number: EP18819033.4A
Authority: EP
Inventors: Patrick MEREDITH; Sudirman WIDIARTO; Paul Morris; Robert WHIFFEN; Harismal NATANEGARA; Michael GREGG; Arief RAHMAN
Original assignee: Filtrona Pte Ltd
Current assignee: Filtrona Pte Ltd
Priority date: 2017-12-08
Filing date: 2018-12-06
Publication date: 2025-08-27
Anticipated expiration: 2038-12-06
Also published as: WO2019110715A1; KR20200096280A; RU2020120025A3; JP2021505166A; GB201720490D0; TW201924548A; CN111432667A; EP3720306A1; RU2020120025A

Description

The present invention relates to a method of production of tobacco smoke filter, especially for cigarettes.
Combined Performance Superior (CPS) tobacco smoke filters are well known. These comprise a filtering core and two wrappers, an inner wrapper and an outer wrapper. The inner wrapper is subjected to an embossing process whereby it is grooved or corrugated over part of its length. This results in the production of channels. Each filter will include a length of grooved inner wrapper ("flutes") and non-grooved inner wrapper ("bars"). These filters have the advantage of providing enhanced filtration efficiency and allowing for use of lower pressure drop to achieve the same filtration efficiency. In addition, the embossed inner wrapper may provide a distinctive end appearance which can be used as an anti-counterfeiting measure.
Tobacco smoke filters which contain an additive release vessel, e.g. a frangible capsule, are also well known. The additive may be a flavouring agent. The smoker applies pressure to the filter to break the capsule thereby resulting in the release of the flavouring agent.
WO2012042199 discloses a tobacco smoke filter comprising an additive vessel spaced longitudinally from a first end of the core. CN102669817 teaches a tobacco smoke filter element comprising solid capsules including flavour agents. GB2490728 discloses a smoking filter comprising one or more additive release components containing additives. WO2011039302 refers to a smoking article filter comprising an additive material and a control apparatus configured to control the access of external air to the additive material.
WO2016012447 discloses a method of forming a filter rod of separated filter material fibres by gathering the filter material fibres along a process path and introducing an additive (such as a capsule) into the gathered filtering material, and then applying a single wrapper around the filter material fibres to form a filter rod. EP3178332 teaches a filter manufacturing machine. WO2007135414 discloses a method for making a tobacco smoke filter which comprises an air-permeable axially extending core.
Inclusion of a capsule or capsules into a CPS filter is highly desirable, providing enhanced filtration performance while also allowing for flavour delivery on demand to the user. Current methods of combination of a CPS filter with a capsule would require the separate production of a CPS filter element and a capsule containing filter element; these would be joined to produce a dual segment filter (e.g. with a common outer wrapper). Such a filter lacks a single unitary core of tobacco smoke filtering material. This method does not allow for provision of a capsule in register with the flute portion of the CPS filter.
Multi-segment filters such as dual segment filters are formed from two of more segments of filtering material. Single segment filters are formed from a single unitary section of filtering material. Multi-segment filters (e.g. dual segment filters) are more costly to produce than single segment filters because of the requirement to make the various segments of filtering material by separate processes and subsequently correctly arrange and abut the different segments to form the multi-segment filter rod.
There is therefore a need for filter that combines the features of a CPS filter with a capsule in a single element filter, i.e. a filter which includes a single unitary core of filtering material. Such a filter would allow for a single pass production process and improved production efficiency.
There is provided a (e.g. single segment) tobacco smoke filter or filter element comprising a longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material, a first (e.g. at least partially corrugated e.g. air permeable) wrapper around the core, and a second wrapper around the first wrapper, the first wrapper defining at least with (e.g. between itself and) the second wrapper at least one (e.g. peripheral) channel extending longitudinally of the filter or filter element, wherein the (or each) longitudinally extending channel extends less than the full length of the filter or filter element such that a longitudinally extending portion of the filter or filter element is free of longitudinally extending channels; the filter or filter element further comprising at least one additive release vessel (e.g. a capsule e.g. a frangible capsule).
The longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material is a single unitary core of tobacco smoke filtering material. In other words the core is formed from one section of filtering material, rather than separate sections e.g. abutted against each other. The filter or filter element comprising a single unitary core of tobacco smoke filtering material is produced more efficiently via a single pass production process. Further, it is possible to position the additive release vessel at a specified position, allowing for on demand flavour delivery to the smoker. An additive release vessel can be positioned in register with the region of the filter or filter element that is free of channels, which provides enhanced flavour release (or enhanced smoking sensation) to the smoker. The filter or filter element may be incorporated into a multi-segment filter as a single segment. This would allow for an increase in the number of features that could be incorporated into the multi-segment filter. A filter element may be joined with a filter element containing a particulate additive e.g. activated carbon granules, allowing for enhanced filtration and on demand flavour delivery to the user. Current methods known in the art involve spraying the flavourant (e.g. menthol) onto tobacco smoke filtering material that includes carbon. This does not allow for on demand release of the flavourant combined with the enhanced filtration properties of carbon. Current methods know in the art also fail to combine additive release vessels and carbon filtration with peripheral longitudinally extending channels which allow for further enhanced filtration.
The first wrapper defines at least with (e.g. between itself and) the second wrapper at least one (e.g. peripheral) channel extending longitudinally of the filter or filter element, wherein the (or each) longitudinally extending channel extends less than the full length of the filter or filter element such that a longitudinally extending portion of the filter or filter element is free of longitudinally extending channels. Preferably there may be 5 or more longitudinally extending channels, for example 5 to 25 longitudinally extending channels, for example 9 to 20 longitudinally extending channels. A filter or filter element of around 20-25 mm circumference may include, for example, 14 to 20 longitudinally extending channels. A filter or filter element of around 16-17 mm circumference may include, for example, 9 to 14 longitudinally extending channels.
The first wrapper is a paper wrapper or an air permeable wrapper. The first wrapper may be an air permeable filtering paper (e.g. corrugated air permeable filtering paper) or a wrapper of cellulose acetate (e.g. corrugated air permeable cellulose acetate). The weight of the inner wrapper may be from 50 grams per square meter to 100 grams per square meter, e.g. 80 grams per square meter.
The first (e.g. air permeable) wrapper has longitudinally extending corrugations which define the longitudinally extending channels at least with (e.g. between itself and) the second wrapper. The first wrapper may be (e.g. at least partially) corrugated, the corrugations providing (defining) [e.g. together with the second wrapper] 5 or more longitudinally extending channels, for example 5 to 25 longitudinally extending channels, for example 9 to 20 longitudinally extending channels. A filter or filter element of around 20-25 mm circumference may include, for example, 14 to 20 longitudinally extending channels (provided by the corrugations). A filter or filter element of around 15-17 mm circumference may include, for example, 9 to 14 longitudinally extending channels (provided by the corrugations). Herein the term corrugated includes the meaning shaped into folds including parallel and alternating ridges and grooves. This incorporation of channels into the filter or filter element allows for improved filtration performance (e.g. improved tar retention) compared to conventional mono acetate filters with the same pressure drop.
The filter or filter element may have a circumference from 10 mm to 30 mm, superslim filters or filter elements of 16 mm.
The (or each) portion of the filter which includes longitudinally extending channels (e.g. around the periphery of the filter) (e.g. which includes corrugations) is referred to herein as a flute or fluted portion. The (or each) part or portion of the filter which does not include longitudinally extending channels (e.g. around the periphery of the filter) is referred to herein as a bar or bar portion.
The filter or filter element comprises at least one channel extending longitudinally from a first end of the filter or filter element, wherein the second end of the filter or filter element is free from longitudinally extending channels. This example may include a flute portion at one end of the filter and a bar portion at the other end of the filter. This configuration may give a more desirable end appearance. Positioning of a flute portion at an end visible to the user allows for visual differentiation between products, for example visual differentiation between products comprising no additive release vessel and products comprising one additive release vessel.
The corrugated first wrapper may be coloured (e.g. green) providing further visual differentiation. The first wrapper may include a pigment. The first wrapper includes a pigment that provides a colour that substantially contrasts to the colour of the tobacco smoke filtering material and/or the second wrapper. The colour of the wrapper may be used to identify the flavour provided by the additive release vessel. The use of a coloured first wrapper may also be used as an anti-counterfeiting measure.
The filter or filter element comprises at least one channel extending longitudinally from the upstream end of the filter or filter element, and at least one channel extending longitudinally from the downstream end of the filter or filter element, and a central portion of the filter or filter element that is free of longitudinally extending channels. This example may include a flute portion at each end and a single central bar portion.
The filter or filter element comprises at least one channel extending longitudinally of the filter or filter element and which extends only part of the filter or filter element length, located in the central portion of the filter or filter element such that the (or a) longitudinally extending channel does not extend from either the upstream or downstream ends of the filter or filter element. This example may include a bar portion at each end and a single central flute portion. This will provide the enhanced filtration performance associated with the presence of longitudinally channels but will not affect end appearance.
The length of each longitudinally extending channel is 2mm or greater, it may be between 2.5mm and 23mm between 3mm and 15mm, or between 3.5mm and 9mm. If the filter has flutes at either end the longitudinally extending channel or channels extending from one end (upstream or downstream) may be a different length to those extending from the other end, or they may be the same length. The longitudinally extending channels at both ends of the filter may be between 7 and 8mm long. The longitudinally extending channels at both ends of the filters may be between 3 and 4mm long, for example 3.75mm long. Provision of longitudinally extending channels of these dimensions means that the performance of the filter (tar retention etc) should be acceptable.
The filter or filter element includes only one additive release vessel (that is, the filter or filter element preferably includes a single additive release vessel, rather than two or more additive release vessels). The filter or filter element may include two or more additive release vessels.
The filter or filter element may comprises at least one additive release vessel in register with the (or a) longitudinally extending portion of the filter or filter element that is free of longitudinally extending channels. The filter or filter element may include only one additive release vessel (that is, the filter or filter element may include a single additive release vessel, rather than two or more additive release vessels). The filter or filter element may include only one additive release vessel, wherein the additive release vessel is in register with the (or a) longitudinally extending portion of the filter or filter element that is free of longitudinally extending channels. This example may include a filter or filter element comprising a flute portion at one end and a bar portion at the other wherein there is an additive release vessel in register with the bar portion. The positioning of an additive release vessel in register with the bar portion supplies a greater yield of flavourant to the user compared to positioning of the additive release vessel in register with the flute portion. Positioning of the additive release vessel in the bar portion is used to provide the user with a higher amount of flavourant. Further, the tobacco smoke filtering material may contain an additive, for example a flavourant to provide the user with an initial yield of flavourant. An additive release vessel may be used to increase the yield of flavourant, allowing the user to vary the smoking experience e.g. provide a boost of flavour during smoking. A second additive release vessel may be used to further increase the yield of flavourant, again allowing the user the vary the smoking experience, e.g. provide a further boost of flavour. The flavourants used in the filtering material and additive release vessel(s) may all be the same flavour, or they may be different flavours (e.g. complimentary flavours).
There is provided a (e.g. single segment) tobacco smoke filter or filter element comprising a longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material, a first (e.g. at least partially corrugates e.g. air permeable) wrapper around the core, and a second wrapper around the first wrapper, the first wrapper defining at least with (e.g. between itself and) the second wrapper at least one (e.g. peripheral) channel extending longitudinally of the filter or filter element, wherein the (or each) longitudinally extending channel extends less than the full length of the filter or filter element such that a longitudinally extending portion of the filter or filter element is free of longitudinally extending channels; the filter or filter element further comprising only one (single) additive release vessel, wherein the (single) additive release vessel is in register with the longitudinally extending portion of the filter or filter element that is free of longitudinally extending channels, wherein the additive release vessel is a capsule and contains an additive in the form of a flavourant. This example may include a filter or filter element comprising a flute portion at one end and a bar portion at the other wherein there is an additive release vessel in register with the bar portion (see e.g. Fig 1, Fig 3). The positioning of an additive release vessel in register with the bar portion supplies a greater yield of flavourant to the user compared to positioning of the additive release vessel in register with the flute portion (Example 4). Positioning of the additive release vessel in the bar portion may be used to provide the user with a higher amount of flavourant. The filter or filter element may comprise at least one additive release vessel in register with the (or a) longitudinally extending portion of the filter or filter element that comprises longitudinally extending channels. The filter or filter element may include only one additive release vessel, wherein the additive release vessel is in register with the (or a) longitudinally extending portion of the filter or filter element that comprises longitudinally extending channels. This example may include a filter or filter element comprising a flute portion at one end and a bar portion at the other wherein there is an additive release vessel in register with the flute portion. The positioning of an additive release vessel in register with the flute portion supplies a lower yield of flavourant to the user compared to positioning of the additive release vessel in register with the bar portion. Positioning of the additive release vessel in register with the flute portion may be used to provide the user with a lower amount of flavourant.
The filter or filter element may comprise at least one additive release vessel in register with a portion of the filter or filter element wherein the (or a) longitudinally extending portion of the filter or filter element that comprises longitudinally extending channels meets the (or a) longitudinally extending portion of the filter or filter element that is free from longitudinally extending channels. The filter or filter element may include only one additive release vessel, wherein the additive release vessel is in register with a portion of the filter or filter element wherein the (or a) longitudinally extending portion of the filter or filter element that comprises longitudinally extending channels meets the (or a) longitudinally extending portion of the filter or filter element that is free from longitudinally extending channels. This example may include a filter or filter element comprising a flute portion at one end and a bar portion at the other wherein there is an additive release vessel in register with the point where the flute portion and bar portion meet.
It may be that the filter or filter element comprises two additive release vessels. If there are two additive release vessel, one additive release vessel may be in register with the (or a) longitudinally extending portion of the filter or filter element that is free from longitudinally extending channels and one additive release vessel may be in register with the (or a) longitudinally extending portion of the filter or filter element that comprises longitudinally extending channels. Including two additive release vessels in the filter allows the user is able to vary the amount of flavourant they receive and increase the amount of flavourant they received compared to a single additive release vessel. The user may break one additive release vessel at the beginning of smoking and one additive release vessel during smoking, allowing the user to vary the smoking experience e.g. provide a boost of flavour during smoking.
It may be the filter or filter element comprises two or more additive release vessels. The additive release vessels may contain the same flavourant, or different flavourants. When they contain different flavourants, the positioning of the additive release vessels in the filter or filter element can be used to provide the user with an optimal combination of flavours. The increased yield of flavourant associated with positioning an additive release vessel in register with a bar portion of the filter or filter element can be used to provide an optimal balance of flavour with an additive release vessel in register with the flute portion.
The (or each) additive release vessel (e.g. a capsule e.g. a frangible capsule) is fully enclosed within the longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material. This means that the additive release vessel (e.g. a capsule) is not visible (to the smoker) at the mouth or buccal end of the filter or filter element, or at the mouth end of a cigarette including a filter. At least one end of the longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material has a uniform appearance.
The additive release vessel may be a capsule, for example a frangible capsule which includes an additive in the form of a flavourant.
The additive release vessel (e.g. a capsule e.g. a frangible capsule) and/or the tobacco smoke filtering material may contain one or more additives, such as a flavourant and/or a liquid, solid or other material, such as activated carbon, e.g. to aid smoke filtration. The additive release vessel and/or tobacco smoke filtering material may further contain stimulants, water, tobacco extracts, smoke altering chemicals and/or agents to promote degradation of the filter. The use of additive containing capsules in filters is well known in the art. The flavourant may be any flavourant known or suitable for use in a smoking article such as a cigarette, for example menthol, spearmint, peppermint, fenugreek, clove etc. Preferably the flavouring agent is or comprises menthol. The additive release vessel (capsule) may comprise more than one flavouring agent (and may provide blends of different flavours, which may or may not include menthol).The filter or filter element may include additive in the form of flavourant [e.g. in the additive release vessel [(e.g. frangible) capsule]], wherein the amount of additive (e.g. including a flavourant) is less than 35mg (per filter/filter element). The filter or filter element may include additive in the form of flavourant [e.g. in the additive release vessel [(e.g. frangible) capsule]], wherein the amount of additive (e.g. including a flavourant) is 5 to 30 mg, for example 15 to 25 mg, for example 10 to 25 mg, for example 10 to 20mg (per filter/filter element).The additive release vessel [(e.g. frangible) capsule] may be of width (when measured at its broadest point in a direction across the filter, that is perpendicular to the direction in which the longitudinally extending core extends) 2 to 5mm, e.g. 2.5 to 4mm, e.g. 2.5 to 3.9mm, e.g. 3.0 to 3.8mm, e.g. 3.2 to 3.7 mm, e.g. 3.35 or 3.5 mm. The additive release vessel [(e.g. frangible) capsule] may include less than 35mg flavourant. The additive release vessel [(e.g. frangible) capsule] may include from 5 to 30 mg, for example 7 to 25 mg, for example 10 to 25 mg, for example 10 to 20 mg flavourant. The filter or filter element may be of length 10 to 30 mm, e.g. 14 to 27 mm, e.g. 17 to 25 mm.
The longitudinally extending (e.g. substantially cylindrical) core comprises tobacco smoke filtering material. The tobacco smoke filtering material may be, for example, any of those materials (usually filamentary, fibrous, web or extruded) which are conventionally employed for tobacco smoke filter manufacture. The tobacco smoke filtering material may be, for example, natural or synthetic filamentary tow, e.g. of cotton or plastics such as polyethylene or polypropylene, or cellulose acetate filamentary tow. It may comprise, for example, natural or synthetic staple fibres, cotton wool, a web material such as paper (usually creped), an (e.g. synthetic) non-woven material, and/or an extruded material (e.g. starch, synthetic foams, extruded foams). The filamentary material may have a filament denier of 2.0 or greater, for example 2.0 to 5.0. The filamentary material may have a total denier of 9,000 to 40,000, for example 30,000. The filtering material may be cellulose acetate tow (e.g. in the form of a cellulose acetate filamentary tow, for example 3.0 Y 30,000 tow). The filtering material may be cellulose acetate to which a plasticiser has been applied (e.g. plasticised filamentary tow). Triacetin is, as is well known in the art, and typically applied to cellulose acetate filters as a plasticiser (e.g. at around 6-8% w/w).
The application discloses double and higher length filter rods and filter element rods, include a plurality of filter rods and filter element rods joined end to end.
According to the present invention in a further aspect there is provided a method of tobacco smoke filter or filter element production (e.g. a method of production of tobacco smoke filters or filter elements as defined in the attached claims) wherein a train of tobacco smoke filtering material is continuously advanced longitudinally, the advancing filtering material is gathered towards rod shape, and the gathered advancing filtering material is shaped to and secured in rod form to provide a continuous rod (of a plurality of filters or filter elements);

wherein additive release vessels (e.g. a capsule e.g. a frangible capsule) are inserted into the gathered advancing filtering material as it is shaped to and secured in rod form; and wherein a first inner wrapper and a second outer wrapper are applied around the gathered advancing filtering material as it is shaped to and secured in rod form (e.g. as or after the additive release vessels are inserted into the gathered advancing filtering material);
the inner wrapper including profiled (e.g. corrugated) portions spaced longitudinally between flat portions, the profiled (e.g. corrugated) portions of the first wrapper defining, with the second wrapper, channels extending longitudinally of the rod, such that the continuous rod (of a plurality of filters or filter elements) includes portions which include longitudinally extending channels separated by portions which do not include longitudinally extending channels, wherein the additive release vessels (e.g. a capsule e.g. a frangible capsule) are inserted into the gathered advancing filtering material in register with flat portions of the first wrapper. Preferably the application of the first inner wrapper and the second outer wrapper around the gathered advancing filtering material shapes the gathered advancing filtering material and secures it in rod form. The continuous rod may be cut to form single filters of filter elements or multiple product rods each comprising a plurality of filters or filter elements. The continuous rod may be cut in register with a profiled portion of the first wrapper (in which case the cut end will expose the longitudinally extending channels) or in register with a flat portion of the first wrapper (in which case the cut end will not expose the longitudinally extending channels).

The additive release vessels (e.g. a capsule e.g. a frangible capsule) are inserted into the gathered advancing filtering material in register with flat portions of the first wrapper as the advancing filtering material is shaped to and secured in rod form (so the additive release vessels are in register with flat portions of the first wrapper). The applicants have found that this method (see Example 3) is efficient and can be run for at least eight hour with acceptable levels of wastage.
The invention provides a method of making a tobacco smoke filter which comprises providing an air-permeable axially extending core, forming around the core a first wrapper of air-permeable material and enwrapping a second wrapper around the wrapped core, the first wrapper defining at least with the second wrapper at least one channel extending longitudinally of the filter, wherein the (or each) longitudinal extending channel extends less than the full length of the filter such that a longitudinally extending portion of the filter is free of longitudinally extending channels, wherein the filter is formed as a continuous rod of a plurality of filters, and wherein the step (or steps) of cutting the continuous rod to form individual filters is arranged so the cut ends form the upstream end of the filter and the downstream end of the filter. Additive release vessels (e.g. a capsule e.g. a frangible capsule) are inserted into the filter or filter elements by methods known in the art. The filters or filter elements produced comprise a unitary core of tobacco filtering material.
The longitudinally extending channels of filters/elements of the invention produced by the claimed method may have a larger cross sectional area compared to conventional CPA and CPF filters of similar diameter that are known in the art, which may have associated benefits in terms of visual appearance (anti-counterfeiting measure). In an example, a filter or filter element of around 20-25 mm circumference may include longitudinally extending channels (provided by the corrugations) having area 5.5 to 7.5 mm², for example 6.5 mm². This is a larger area than a CPF or CPA filter of similar circumference (CPF channel area 4 mm², CPA filter area 5mm²). In another example, a filter or filter element of around 15-17 mm circumference may include longitudinally extending channels (provided by the corrugations) having area 4.5 to 6.5 mm², for example 5 mm². This is a larger area than a CPF or CPA filter of similar circumference (CPF channel area 3 mm², CPA filter area 4mm²).
The method of production of the present invention allows for use of standard cellulose acetate tow items. It will be appreciated that other materials that are well known in the art may be used to form the tobacco smoke filter material, first wrapper, second wrapper and additive release vessel.
The applicants have found that by locating the bar region in the centre of the filter, rather than at one end, the filter will always be cut at both ends in a fluted region. The bar length will not be affected by variation in cutting, and the performance (e.g. the pressure drop) of the final filter will be more consistent.

FIGURE 1 shows a perspective view, not to scale, with parts broken away, of a filter;
FIGURE 2 shows a perspective view, not to scale, with parts broken away, of a filter;
FIGURE 3 shows a schematic cross-sectional view of the filter illustrated in Figure 1 when cut along its longitudinal axis.
FIGURE 4 shows schematic cross-sectional views of three examples where the capsule position and/or number of capsules has been varied.

Example 1

In Figure 1, a filter 1 comprises a longitudinally extending cylindrical core 2 of tobacco smoke filtering material in the form of cellulose acetate tow (filament denier of 3.0, total denier of 30,000). Surrounding the core 2 is a first wrapper 3 of air-permeable filter paper (basis weight 80 gsm) which has been embossed to provide corrugations along part of its length. A second wrapper 4 of non-corrugated air-permeable filter paper (27 gsm basis weight) is wrapped around the first wrapper 3. The first wrapper 3 is embossed to provide corrugations over approximately half of its length such that it is corrugated towards one end 1a of the filter 1 and smooth at a second end 1b of the filter 1. The corrugated part of the first wrapper 3 towards end 1a defines, between itself and the non-corrugated second wrapper 4, twenty four channels 5a that extend longitudinally of the filter around the periphery of the core (i.e. peripheral channels). The tobacco filtering core 2 surface conforms to the corrugations in the first wrapper 3. The corrugated first wrapper 3 is corrugated over only part of its length such that the longitudinally extending channels 5a extend less than the full length of the filter so that a longitudinally extending portion 6 of the filter 1 is free of longitudinally extending channels. The filter also contains a frangible capsule 9 which includes a menthol flavouring agent. Capsule 9 is fully enclosed within the core 2 of the tobacco smoke filtering material and is not visible, although the approximate position in register with portion 6 of the filter (without channels) is shown by a dotted circle.
The portion of the filter 7 that includes longitudinally extending channels 5a around the periphery of the filter may be referred to as a flute or fluted portion. The portion 6 of the filter that does not include longitudinally extending channels around the periphery of the filter may be referred to as a bar or bar portion.
Figure 3 illustrates a schematic cross-sectional view of Figure 1 when cut along the filter's longitudinal axis. It can be seen that capsule 9 is in register with the portion of the filter 6 which does not include longitudinally extending peripheral channels 5a.
The filter 1 may be joined to a wrapped tobacco rod to form a cigarette, by methods well known in the art. The filter may, for example, be joined to the wrapped tobacco rod by ring tipping [which engages around just the adjacent ends of the (wrapped) filter and rod to leave much of the filter wrap exposed]. The filter may, for example, be joined by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod). If the bar portion of the filter 1 is joined to the tobacco rod, the flute portion of the filter will be visible at the mouth end of the cigarette. This can be used as an anti-counterfeiting measure. The first wrapper 3 may be coloured (i.e. may include a pigment). For example, the first wrapper 3 may be coloured green so as to contrast with the colour of the tobacco smoke filtering material (which is generally white). This colour further differentiates the filter for anti-counterfeiting purposes and may serve to identify the flavour. If the flute portion of filter 1 is joined to the tobacco rod, the bar portion of filter 1 will be positioned at the mouth end of the cigarette. This provides the usual cigarette appearance but with the enhanced filtration properties that are associated with the channels present.

Example 2

In Figure 2, a filter 101 comprises a longitudinally extending cylindrical core 102 of tobacco smoke filtering material in the form of cellulose acetate tow (filament denier of 3.0, total denier of 30,000). Surrounding the core 102 is a first wrapper 103 of air-permeable filter paper (basis weight 80 gsm) which has been embossed to provide corrugations along part of its length. A second wrapper 104 of non-corrugated air-permeable filter paper (27 gsm basis weight) is wrapped around the first wrapper 103. The first wrapper 103 is embossed to provide corrugations over approximately half of its length such that it is corrugated towards one end 101a of the filter 101 and smooth at a second end 101b of the filter 101. The corrugated part of the first wrapper 103 towards end 101a defines, between itself and the non-corrugated second wrapper 104, twenty four channels 105a that extend longitudinally of the filter around the periphery of the core (i.e. peripheral channels). The tobacco filtering core 102 surface conforms to the corrugations in the first wrapper 103. The corrugated first wrapper 103 is corrugated over only part of its length such that the longitudinally extending channels 105a extend less than the full length of the filter so that a longitudinally extending portion 106 of the filter 101 is free of longitudinally extending channels (and a longitudinally extending portion 107 of the filter includes longitudinally extending channels 105a). The filter also contains a frangible capsule 109 which includes a menthol flavouring agent. Capsule 109 is fully enclosed within the core 102 of the tobacco smoke filtering material and is not visible, although the approximate position in register with portion 107 of the filter (which includes longitudinally extending channels 105a) is shown by a dotted circle.
The portion of the filter 107 that includes longitudinally extending channels 105a around the periphery of the filter may be referred to as a flute or fluted portion. The portion 106 of the filter that does not include longitudinally extending channels around the periphery of the filter may be referred to as a bar or bar portion.
It will be appreciated that the filter 101 may be joined to a wrapped tobacco rod to form a cigarette, by methods well known in the art. The filter may, for example, be joined to the wrapped tobacco rod by ring tipping [which engages around just the adjacent ends of the (wrapped) filter and rod to leave much of the filter wrap exposed]. The filter may, for example, be joined by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod). If the bar portion of the filter 101 is joined to the tobacco rod, the flute portion of the filter will be visible at the mouth end of the cigarette. This can be used as an anti-counterfeiting measure. The first wrapper 103 may be coloured (i.e. may include a pigment). For example, the first wrapper 103 may be coloured green so as to contrast with the colour of the tobacco smoke filtering material (which is generally white). This colour further differentiates the filter for anti-counterfeiting purposes and may serve to identify the flavour. If the flute portion of filter 101 is joined to the tobacco rod, the bar portion of filter 101 will be positioned at the mouth end of the cigarette. This provides the usual cigarette appearance but with the enhanced filtration properties that are associated with the channels present.

Example 3

The filter or filter element according to the present invention (e.g. that of Figures 1 and 2) may be produced in the following manner. The methods and machinery are well known in the art. The filter is produced using a modified mono acetate filter machine (known in the art). The machine requires a CPS kit and a Capsule Inserter kit that are known in the art. The filters are produced via the production of a multiple length rod. The machine tow processing is set to form a longitudinally extending unitary rod of cellulose acetate tow. The machine is then set to feed in air-permeable filter paper and perform embossing on the air-permeable filter paper resulting in the registration of the flute (embossed, corrugated) portions and the bar portions on the filters. The capsule inserter kit is then set to insert capsules into the cellulose acetate tow at defined positions. By using different change parts for the Capsule Inserter kit capsules may be inserted at the bar portion, flute portion or at the join of a bar and flute portion. A filter containing two capsules may also be produced. The step (or steps) of cutting the continuous rod to form individual filters is arranged so the cut ends form the upstream end of the filter and the downstream end of the filter. The method allows for the features of the filter to be customisable to requirement, e.g. the capsule position, flute orientation and colour of the plug wrap can all be varied with ease.

Example 4

An experiment was performed in order to measure the affect that capsule position had on the menthol yield the cigarette user received. Four filter embodiments A to D were tested. The filters were made by the method of Example 3. All filters tested comprised a bar portion at one end, a flute portion at the other end and at least one capsule containing menthol additive. It was envisaged that the flute end of the filter is the end that would be in register with the user's mouth. Menthol yield was therefore measured from the flute end. Filter A is a filter according to Figure 1 and was tested without crushing the single capsule. Filter B is a filter according to Figure 1 comprising a single capsule in register with the bar portion that was crushed to release the menthol additive prior to testing. A cross-sectional view of filter B is shown in Figure 4. Filter C is a filter according to Figure 3 comprising a single capsule in register with the flute portion that was crushed prior to testing. A cross-sectional view of filter C has been shown in Figure 4. Filter D comprised a single capsule in register with the bar portion and a single capsule in register with the flute portion. Both capsules were crushed prior to testing. A cross-sectional view of filter D has been shown in Figure 4.
The menthol retention data for each filter was measured by methods well known in the art. The measurements were repeated four times for each filter embodiment. The results have been illustrated in Tables 1 to 4. The pad measurement data indicates the yield of menthol in the smoke. The average menthol smoke yield for the filters has been summarised in the Tables 1 to 4. Table 1

Uncrushed (Filter A) Menthol on pad / mg Menthol in filter / mg

1 0.004 5.81

2 0.004 4.79

3 0.004 2.53

4 0.004 5.51

Average 0.004 4.66

Table 2

Crushed in bar (Filter B) Menthol on pad / mg Menthol in filter / mg

1 0.94 6.25

2 0.91 6.11

3 0.91 4.97

4 1.03 7.89

Average 0.95 6.31

Table 3

Crushed in flute (filter C) Menthol on pad / mg Menthol in filter / mg

1 0.88 7.32

2 0.83 6.90

3 0.87 7.99

4 0.89 6.14

Average 0.87 7.09

Table 4

Both crushed (filter D) Menthol on pad / mg Menthol in filter / mg

1 1.57 8.43

2 1.51 8.27

3 1.45 8.52

4 1.62 8.31

Average 1.54 8.38
The menthol yield in the smoke is higher when the crushed capsule is positioned in register with the bar portion. Without wanting to be bound by theory, it is thought that the flutes allow by-passing of the smoke to the mouth end and thus less menthol is retained in the cellulose acetate filter material. Further, crushing one capsule in the bar portion and one capsule in the flute portion (Filter D) does not equal the yield that would be obtained by adding together the menthol yield data for filters B and C. The variety of menthol smoke yields obtained indicates that the flavour yield may be varied depending on the capsule position.

Claims

A method of tobacco smoke filter or filter element production wherein a train of tobacco smoke filtering material is continuously advanced longitudinally, the advancing filtering material is gathered towards rod shape, and the gathered advancing filtering material is shaped to and secured in rod form to provide a continuous rod;
wherein additive release vessels are inserted into the gathered advancing filtering material as it is shaped to and secured in rod form; and

wherein a first inner wrapper and a second outer wrapper are applied around the gathered advancing filtering material as it is shaped to and secured in rod form;

the inner wrapper including profiled portions spaced longitudinally between flat portions, the profiled portions of the first wrapper defining, with the second wrapper, channels extending longitudinally of the rod, such that the continuous rod includes portions which include longitudinally extending channels separated by portions which do not include longitudinally extending channels, wherein the additive release vessels are inserted into the gathered advancing filtering material in register with flat portions of the first wrapper.