EP2874510A2

EP2874510A2 - Tobacco smoke filter

Info

Publication number: EP2874510A2
Application number: EP13741698.8A
Authority: EP
Inventors: Ronald Paul MORRIS; Roy Alingalan; Ahmad Fashihul Lisan
Original assignee: Essentra Filter Products Development Co Pte Ltd
Current assignee: Filtrona Development Co Pte Ltd
Priority date: 2012-07-18
Filing date: 2013-07-16
Publication date: 2015-05-27
Also published as: WO2014012917A2; JP2015522285A; GB201212822D0; CN104780792A; WO2014012917A3; CN104780792B; JP6417325B2

Abstract

The present invention provides a tobacco smoke filter or filter element having a fixed length comprising a wrapper engaged around a downstream core of tobacco smoke filtering material and a further core longitudinally aligned therewith; wherein the further core is reversibly moveable relative to the wrapper along the longitudinal axis of the filter.

Description

Tobacco Smoke Filter

The present invention relates to tobacco smoke filters and filter elements, e.g. for smoking articles such as cigarettes.

The concept of a filter cigarette in which the smoker can adjust the filter to alter the smoking experience is well-known. For example, the smoker can break a frangible capsule within the filter to release flavour, or divert smoke or air through different pathways that, for example, contain different filter or flavour materials. Many of these concepts operate by enabling the smoker to change the level of filter ventilation, thereby altering the strength or concentration of the smoke drawn in. One such example is disclosed in US 4646763. This filter was featured on the Philip Morris brand 'Concord'. This product, together with many designs that adjust the level of ventilation, is operated by a rotational mechanism in which the smoker turns one filter component whilst another component remains stationary.

Adjustable filters that are operated by longitudinal movement instigated by the smoker are also known. One example is disclosed in GB 2194427, assigned to Cigarette Components Ltd. In this product, there is a central filter element that can be moved to be in register with, or out of registration with, an outer ventilating sleeve thereby enabling the level of ventilation to be changed. The product also features a mouth end co-axial filter element in which the central core component is not adhered to the surrounding annulus. In operation, the smoker pushes in the central core component of the mouth end element which in turn moves (in a manner analogous to a piston connecting rod driving a piston) the central filter element out of register with the ventilation holes, thereby increasing the level of ventilation. However, this product suffers from a number of shortcomings: (a) the position of the movable central component may alter accidentally, e.g. during transportation, so the smoking characteristics would not be as expected, and the smoker would be unaware of this because the internal filter structure is obscured by opaque plugwrap tipping paper; (b) the adjustment is not reversible - i.e. after the central element has been moved by means of the central core component, it cannot be returned to its original position should the smoker wish to readjust the product; (c) the downstream core can accidentally be ejected out of the filter, e.g. through vibration or chewing on the filter; and (d) the product requires reasonable dexterity by the consumer in use.

More recently, WO 201 1/121325 and WO 201 1/121327 (BAT) have been published, both of which discuss numerous concepts for filters adjustable in the longitudinal direction. However, these entail movement of the filter relative to the tobacco rod - i.e. the overall length of the smoking article would tend to change as a result of the adjustment. The present invention provides for an adjustable filter cigarette that overcomes the aforementioned shortcomings of the prior art. The level of adjustment is (or may be) visible to the smoker; the adjustment is reversible; there is no inadvertent ejection of filter components; it is simple to use; and there is no filter or cigarette length change as a result of the adjustment. Furthermore, the filter/filter element/filter cigarette of the invention is straightforward to assemble using conventional cigarette filter materials and manufacturing technologies.

According to the present invention there is provided a tobacco smoke filter or filter element having a fixed length (i.e. a fixed-length filter or filter element) comprising a wrapper (e.g. an outer wrapper) engaged around a downstream (e.g. longitudinally extending, e.g. substantially cylindrical) core of tobacco smoke filtering material and a further (e.g. longitudinally extending, e.g. substantially cylindrical) core (e.g. of tobacco smoke filtering material) longitudinally aligned therewith; wherein the further core is reversibly moveable (e.g. reversibly adjustable, reversibly slidable) relative to the wrapper along (e.g. up and down) the longitudinal axis of the filter.

Preferably the wrapper (e.g. outer wrapper) includes a region of ventilation.

Preferably the wrapper (e.g. outer wrapper) includes a region of ventilation comprising at least one ring or annulus of ventilation holes around the circumference of the filter/filter element.

The wrapper (e.g. outer wrapper) is preferably transparent, as discussed below.

The further core is reversibly moveable (e.g. reversibly adjustable, reversibly slidable) in both directions along the longitudinal axis of the filter. The further core is reversibly moveable between (may be moved to and from) positions where it is in register (e.g. blocking register), or partially in register (e.g. blocking register) with a, or the, region of ventilation, and positions where it is not in register (e.g. blocking register) with a, or the, region of ventilation. This means that the smoker may reversibly adjust the further core so it does not block the ventilation, or partially or wholly blocks the ventilation, by sliding the further core along the longitudinal axis of the filter, and thereby alter the ventilation and thus smoking experience.

According to the present invention in an aspect there is provided a tobacco smoke filter or filter element comprising:

a downstream (e.g. longitudinally extending, e.g. substantially cylindrical) core of tobacco smoke filtering material;

an upstream (e.g. longitudinally extending, e.g. substantially cylindrical) core of tobacco smoke filtering material spaced longitudinally (upstream)of the downstream core; a wrapper (e.g. an outer wrapper) engaged around and joining the spaced upstream and downstream cores; and

a further (e.g. longitudinally extending, e.g. substantially cylindrical) core (e.g. of tobacco smoke filtering material) located between, and longitudinally aligned with, the downstream and upstream cores;

wherein the further core is reversibly moveable (e.g. reversibly adjustable, reversibly slidable)between the spaced upstream and downstream cores along (e.g. in both directions e.g. up and down) the longitudinal axis of the filter (e.g. relative to the wrapper).

The further core is moveable (e.g. reversibly moveable, reversibly adjustable, reversibly slidable) by (the smoker) pushing or pinching on the e.g. outer) wrapper, for example in a manner analogous to the ejection of Roll-Your-Own filter elements from a 'Pop-a-Tip' product, as is well known in the art.

Preferably the tobacco smoke filter or filter element has a fixed length (i.e. is a fixed- length filter or filter element).

Herein the term "downstream" means towards the end of the filter/filter element/filter cigarette which is closest to the mouth of the smoker of a filter cigarette (e.g. when the filter/filter element is attached to a tobacco envelope in a filter cigarette). The term

"upstream" means towards the end of the filter/filter element which is closest to the tobacco envelope of the filter cigarette (e.g. when the filter/filter element is attached to a tobacco envelope in a filter cigarette). Herein the terms "fixed length" and "fixed-length filter or filter element" means the filter/filter element (and any smoking article such as filter cigarette to which it is attached) has an end to end measurement (extent) along the longitudinal axis which is fixed, that is, does not change (e.g. when the filter is adjusted e.g. by moving the further core). Herein, the term "reversibly" (in reversibly moveable, reversibly adjustable, reversibly slidable) means that, once moved, slid or adjusted, the further core may be moved (slid, adjusted) again such that it may be returned to its original position (e.g. it can be moved back to its original position should the smoker wish to readjust the product again, or if it has moved out of position for some reason).

Preferably the filter or filter element includes a region of ventilation (e.g. includes ventilation holes), between the spaced upstream and downstream cores. Preferably the region of ventilation is located towards the upstream core or towards the downstream core. Preferably the region of ventilation comprises at least one ring or annulus of ventilation holes around the circumference of the filter/filter element (between the spaced upstream and downstream cores). Preferably the wrapper (e.g. outer wrapper) includes the region of ventilation. Preferably the wrapper (e.g. outer wrapper) includes a region of ventilation comprising at least one ring or annulus of ventilation holes around the circumference of the filter filter element between the spaced upstream and downstream cores.

The further core is reversibly moveable (e.g. reversibly adjustable, reversibly slidable) in both directions along the longitudinal axis of the filter(between the spaced upstream and downstream cores). The further core is reversibly moveable between (may be moved to and from)positions where it is in register (e.g. blocking register), or partially in register (e.g. blocking register) with a, or the, region of ventilation, and positions where it is not in register (e.g. blocking register) with a, or the, region of ventilation. This means that the smoker may reversibly adjust the further core so it does not block the ventilation, or partially or wholly blocks the ventilation, by sliding the further core between the spaced upstream and downstream cores, and thereby alter the ventilation and thus smoking experience.

Preferably the wrapper (e.g. outer wrapper) is transparent. It will be appreciated that a transparent wrapper (e.g. outer wrapper) has the advantage that the smoker can clearly see the position of the further (moveable) core of tobacco smoke filtering material in relation to the regions of ventilation(and the spaced upstream and downstream cores). The wrapper (e.g. outer wrapper) may be formed from any suitable transparent material. The wrapper (e.g. outer wrapper) may be, for example, orientated polypropylene, biaxially orientated polypropylene or cellophane. Polypropylene is preferred because it tends to be stiffer and less prone to shrinkage during heat treatment processes. Preferably, the wrapper (e.g. outer wrapper) is resilient such that it retains or substantially retains its original shape after being squeezed. It will be appreciated a non-transparent wrapper (e.g. outer wrapper) may be used according to the invention (for example the wrapper may be a paper, e.g. a plugwrap), although the benefits associated with the smoker being able to see the position of the movable further core will be lost.

The upstream core and/or the downstream core may be adhered to the

wrapper(e.g. outer wrapper). Preferably the upstream core and the downstream core are adhered to the wrapper, e.g. by adhesive. Preferably the adhesive is a hot melt adhesive or an emulsion-based (e.g. EVA, PVA or PVOH) adhesive. The adhesive may be applied by a spray system. The adhesive is preferably disposed (e.g. exclusively) in a localised area or localised areas (e.g. as a discrete patches or portions). The adhesive is preferably disposed (e.g. exclusively) in a localised area or localised areas (e.g. as a discrete patches or portions) positioned between the wrapper and the downstream core and/or the upstream core (if present). Preferably adhesive is not present on the inner surface of the wrapper in the region between the spaced upstream and downstream cores (so longitudinal movement of the further core relative to the wrapper is not hindered by adhesive on the wrapper). Preferably the further (e.g. longitudinally extending, e.g. substantially cylindrical) core comprises a tobacco smoke filtering material.

The downstream filtering core, the further filtering core and the upstream filtering core (if present)may comprise a tobacco smoke filtering material. The tobacco smoke filtering materials for the cores may be the same or different. The tobacco smoke filtering material may be for example any of those materials (usually filamentary, fibrous, web or extruded) conventionally employed for tobacco smoke filter manufacture. The filtering material may be natural or synthetic filamentary tow, e.g. of cotton or plastics such as polyethylene or polypropylene, or cellulose acetate filamentary tow. It may be, for example, natural or synthetic staple fibres, cotton wool, web material such as paper (usually creped) and (e.g. synthetic) non-wovens, and extruded material (e.g. starch, synthetic foams, extruded foams). The filtering material may be cellulose acetate.

The downstream filtering core, the further filtering core and the upstream filtering core (if present) may each include a core wrapper engaged around the (e.g. longitudinally extending, substantially cylindrical) core. The wrapper may be a paper, e.g. plugwrap paper.

The downstream filtering core, the further filtering core and the upstream filtering core (if present) may each include additive, e.g. particulate additive, e.g. activated carbon.

As described above, the further (e.g. longitudinally extending, e.g. substantially cylindrical) core may comprise a tobacco smoke filtering material. Preferably the tobacco smoke filtering material is cellulose acetate. The further (e.g. longitudinally extending, e.g. substantially cylindrical) core may include a further core wrapper.e.g. plugwrap, e.g. non- permeable plugwrap, engaged around the core. The further core may be a non-wrapped substantially cylindrical core of cellulose acetate, for example such as a non wrapped acetate ( WA) filter segment such as is well known in the art. It will be appreciated that a wrapped further core may have an increased blocking effect on the ventilation, especially if the wrapper is non-permeable. The applicants have found that a non wrapped cellulose acetate filter is readily slidable along the length of the filter by the consumer, and is less likely to be deformed as a result of a 'pinching' action by consumers.

The tobacco smoke filter or filter element may include a flavouring agent. One or more of the downstream filtering core, the further filtering core, and the upstream filtering core (if present) may include a flavouring agent. The flavouring agent may be any flavouring agent known for use in tobacco smoke filters or filter elements. For example, the flavouring agent may be menthol, spearmint, peppermint, nutmeg, cinnamon, clove, lemon, chocolate, peach, strawberry, vanilla etc. The agent may contain nicotine or a salt or derivative thereof. Preferably the flavouring agent is menthol. If more than one core includes flavouring agent, the flavouring agents may be the same or different.

One or more of the downstream filtering core, the further filtering core, and the upstream filtering core (if present) may optionally be coloured or tinted (e.g. using appropriate dyes or pigments, preferably those with regulatory approval for use in food contact applications) and/or may include a coloured or tinted wrapper (e.g. coloured using appropriate dyes or pigments, preferably those with regulatory approval for use in food contact applications). The (or each) core may be of, or have a wrapper of, a contrasting colour to the tobacco smoke filtering material. The dye or pigment may preferably be any colour which contrasts with the (e.g. white) tobacco smoke filtering material, for example green, blue, red, orange etc. Each core may be of the same colour, or a different colour, to the other core(s). The use of coloured cores, especially with a transparent (outer) wrapper, provides a product filter, element or rod with a distinctive appearance that is useful for anti-counterfeit purposes.

The tobacco smoke filter or filter element may be of length 12 to 40 mm, e.g. 17 to 35 mm, e.g. 20 to 30 mm.

The tobacco smoke filter (or filter element) may be of circumference 14 to 28 mm, for example 16 to 26mm, for example 16 to 17 mm or 24 to 25 mm. The circumference of the inner face of the wrapper and the outer circumference of the further core (filtering plug) are preferably dimensioned such that there is a snug fit between the two, e.g. such that the further core (filtering plug) may be slid along the longitudinal axis of the filter relative to the wrapper by the application of force to the wrapper, but will not slide without the application of such force (so it will not be liable to move inadvertently during transport or when being drawn on by the smoker). For a further (e.g. longitudinally extending, e.g. substantially cylindrical) core that has a plugwrap (further core wrapper), the circumference of further (e.g. longitudinally extending, e.g. substantially cylindrical) core will preferably be around 0.25mm less than the circumference of the outer, e.g. transparent, wrapper. For a non- wrapped further (e.g. longitudinally extending, e.g. substantially cylindrical) core the circumference may be slightly greater, e.g. around 0.25mm, than that of the outer wrapper.

In a filter cigarette according to the invention, a filter of the invention (or a filter which includes a filter element of the invention) is joined to a wrapped tobacco rod with one end of the filter towards the tobacco. The filter may 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], for example transparent ring tipping. The filter may be joined by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod), in which case the full tipping overwrap is preferably transparent. The filter, filter element or filter cigarette according to the invention may be ventilated by methods well known in the art, e.g. by use of a pre-perforated or air- permeable outer wrapper (e.g. transparent wrapper), and/or laser perforation of the outer wrapper (e.g. transparent wrapper) and, if present, (e.g. transparent) tipping overwrap. A ventilating full tipping overwrap may likewise be inherently air-permeable or provided with ventilation holes, and in ventilated products where both outer wrapper (e.g. transparent wrapper)and tipping overwrap are present ventilation through the overwrap will usually (and preferably) be in register with that through the plugwrap. Ventilation holes through the filter outer wrapper (e.g. transparent wrapper), or through a tipping overwrap, or through both simultaneously, may be made by laser perforation during filter or filter cigarette production, as is well known in the art.

A filter cigarette (or filter/filter element) may have, for example, from 20% to 95% ventilation when the further core is not in register (e.g. blocking register) with the (region of) ventilation. A filter cigarette (or filter/filter element) may have, for example, from 0% to 40% ventilation when the further core is in register (e.g. blocking register) with the (region of) ventilation. It will be understood that the level of ventilation of any filter/filter cigarette will be greater when the further core is not in register (e.g. blocking register) with the (region of) ventilation (because e.g. the ventilation holes are open). The concept of ventilation is well known in the art and means the proportion (%) of air which is drawn through the mouth end which is drawn in through ventilation. For example, if 50mL of air is drawn through the mouth end of a filter cigarette having a ventilation of 60%, 30ml_ (60%) comes through ventilation, and 20ml_ (40%) is drawn through the tobacco end of the cigarette.

According to the invention in a further aspect there is provided a multiple rod comprising a plurality (e.g. 2, 4, 6 etc.) of filters (or filter elements) as described above and/or herein integrally joined end-to-end in a mirror image relationship.

The present invention will now be illustrated with reference to the following

Examples and the attached drawings in which FIGURE 1 schematically illustrates a filter according to a first embodiment of the invention; and FIGURE 2 schematically illustrates a filter according to a different embodiment of the invention.

FIGURE Ishowsa filter 10 according to a first embodiment of the invention. The filter 10 includes a transparent wrapper (e.g. an outer wrapper) 5 engaged around a downstream longitudinally extending, substantially cylindrical, core of tobacco smoke filtering material 1 and a further longitudinally extending, substantially cylindrical, core of tobacco smoke filtering material 2 longitudinally aligned therewith, wherein the further core 2 is moveable relative to the wrapper 5 along the longitudinal axis of the filter.

Thus, the filter includes a downstream longitudinally extending, substantially cylindrical, core 1 of tobacco smoke filtering material in the form of a cellulose acetate plug; and an upstream longitudinally extending, substantially cylindrical, core 4 of tobacco smoke filtering material (also in the form of a cellulose acetate plug), which is spaced longitudinally upstream of the downstream core. The filter includes a transparent wrapper 5 which is engaged around and joins the spaced upstream core 1 and downstream core 4. The spaced upstream core 1 and downstream core 4are secured in place on the radially inner face of the wrapper by EVA or other suitable anchorage adhesive. The EVA may be selectively applied using a spray pulse system such that anchoring adhesive is located between wrapper 5 and cores 1 , 4, but is not present on the radially inner face of the wrapper between the spaced upstream core 1 and downstream core 4. Transparent wrapper 5 of polypropylene includes a region of ventilation 6 between the spaced upstream core 1 and downstream core 4. The region of ventilation 6 is towards the upstream end of the region between spaced upstream core 1 and downstream core 4(i.e. is close to upstream core 4). The region of ventilation comprises three rings 7 of ventilation holes around the circumference of the filter/filter element.

The filter 10 includes a further longitudinally extending, substantially cylindrical, core 2 of tobacco smoke filtering material located between, and longitudinally aligned with, the downstream and upstream cores, in the form of a cellulose acetate filter element wrapped with a further non-porous paper core wrapper (further core wrapper not shown). It will be appreciated that no anchorage adhesive is present between the inner face of the wrapper 5 and the outer face of further core 2.

The tobacco smoke filter is of length 30mm and circumference around 25 mm. The circumference of the inner face of the wrapper 5 and the outer circumference of the further core (filtering plug) 2 are dimensioned such that there is a snug fit between the inner face of the wrapper 5 and the outer circumference of the further core 2; the circumference of core 2 is around 0.25mm less than the circumference of wrapper 5. This means that the further core 2 may be slid along the longitudinal axis of the filter relative to the wrapper 105 by the application of force to the wrapper (see below), but will not slide without the application of such force (so it will not be liable to move inadvertently during transport or when being drawn on by the smoker).

As can be seen in Fig 1 , the transparent wrapper 5 (which is engaged around and joins the spaced upstream core 1 and downstream core 4) defines a cavity 3 between the downstream end of upstream core 4 and the upstream end of further core 2.

The filter 10 is joined to a wrapped tobacco rod 9 with the upstream core 4 towards the tobacco. The filter 10 is joined to the wrapped tobacco rod 9 by ring tipping [which engages around just the adjacent ends of the (wrapped) filter and rod to leave much of the transparent wrapper 5 exposed], by methods which are well known in the art. In an alternative embodiment, the filter may be joined by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod 9), in which case the full tipping overwrap is preferably transparent.

The further core 2 is reversibly moveable (slidable) relative to the wrapper between the upstream and downstream cores 1 , 4 along the longitudinal axis of the filter. As shown in Figure 1 , further core 2 is in the downstream position, i.e. abutting downstream core 1. In this position, ventilating air can enter the filter through the rings 7 of ventilation holes and pass through cores 1 and 2. When the smoker pushes on or pinches the outside of the filter 10, on the outer face of wrapper 5 approximately in the region between downstream core 1 and further core 2, the smoker can adjust the location of further core 2 by sliding it upstream along the longitudinal axis of the filter to a desired position in the region between cores 1 and 4. The smoker may slide the further core 2 to a position where it is in blocking register, or partially in blocking register, with one or more of rings 7 of ventilation holes, such that further core partially or wholly blocks the ventilation, to thereby alter the ventilation and thus smoking experience. In other words, the smoker is able to 'block' some or all of the rows of ventilation holes because ventilating air cannot pass through the non-porous further core wrapper on the further core 2. It will be appreciated that there may still be some leakage of air into the filter; it is not the objective of the invention to create an airtight seal. When further core 2 is slid to an upstream position, the pressure drop and filtration characteristics of the filter will differ compared to when further core 2 is in the downstream position shown in Figure 1 , as will be appreciated by those skilled in the art. It will be appreciated that the movement of the further core 2 is reversible; the smoker may slide the further core 2 longitudinally relative to the wrapper to a different position, or back to the original position, in a similar manner by pushing on or pinching the outside of the filter in the region of further core 2.

The wrapper (e.g. outer wrapper) 5 is resilient such that it retains or substantially retains its original shape after being squeezed.

The tobacco smoke filter 10 (and the overall filter cigarette to which it is attached ) has a fixed length. In other words the filter 10(and the cigarette to which it is attached) has an end to end measurement along the longitudinal axis which is fixed, and does not change (e.g. when the filter is adjusted by the smoker by moving the further core 2).

FIGURE 2 shows a filter 100 according to a further embodiment of the invention. The filter 100 includes a transparent wrapper (e.g. an outer wrapper) 105 engaged around a downstream longitudinally extending, substantially cylindrical, core of tobacco smoke filtering material 101 and a further longitudinally extending, substantially cylindrical, core of tobacco smoke filtering material 102 longitudinally aligned therewith; wherein the further core 102 is moveable relative to the wrapper 105 along the longitudinal axis of the filter.

Thus, the filter includes a downstream core 101 of tobacco smoke filtering material in the form of a cellulose acetate plug; and an upstream longitudinally extending, substantially cylindrical, core 104 of tobacco smoke filtering material (also in the form of a cellulose acetate plug), which is spaced longitudinally upstream of the downstream core. The filter includes a transparent wrapper 105 which is engaged around and joins the spaced upstream core 101 and downstream core 104. The spaced upstream core 101 and downstream core 104are secured in place on the radially inner face of the wrapper by EVA or other suitable anchorage adhesive. The EVA may be selectively applied using a spray pulse system such that anchoring adhesive is located between wrapper 105 and cores 101 , 104, but is not present on the radially inner face of the wrapper between the spaced upstream core 101 and downstream core 104. Transparent wrapper 105 of polypropylene includes a region of ventilation 106 between the spaced upstream core 101 and

downstream core 104. The region of ventilation 106 is towards the downstream end of the region between the spaced upstream core 101 and downstream core 104 (i.e. is close to downstream core 101). The region of ventilation comprises three rings 107 of ventilation holes around the circumference of the filter/filter element.

The filter 100 includes a further longitudinally extending, substantially cylindrical, core 102 of tobacco smoke filtering material located between, and longitudinally aligned with, the downstream and upstream cores, in the form of a cellulose acetate filter element wrapped with a further non-porous paper core wrapper (further core wrapper not shown). It will be appreciated that no anchorage adhesive is present between the inner face of the wrapper 105 and the outer face of further core 102.

As seen in Fig 2, the transparent wrapper 105 (which is engaged around and joins the spaced upstream core 101 and downstream core 104) defines a cavity 103 between the downstream end of further core 2 and the upstream end of downstream core 1.

The filter 100 is joined to a wrapped tobacco rod 109 with the upstream core 104 towards the tobacco. The filter 100 is 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 transparent wrapper 105 exposed], by methods which are well known in the art. In an alternative embodiment, the filter may be joined by a full tipping overwrap (which engages around the full filter length and the adjacent end of the tobacco rod 109), in which case the full tipping overwrap is preferably transparent.

The further core 102 is reversibly moveable (slidable) relative to the wrapper (within the cavity 103) in both directions along the longitudinal axis of the filter. As shown in Figure 2, further core 102 is in the upstream position, i.e. abutting upstream core 104. In this position, ventilating air can enter the filter through the rings 107 of ventilation holes and pass through core101 to the smoker. When the smoker pushes on or pinches the outside of the filter 100, on the outer face of wrapper 105 approximately in the region between upstream core 104 and further core 102, the smoker can adjust the location of further corel 02 by sliding it downstream along the longitudinal axis of the filter to a desired position in the region between cores 101 and 104. The smoker may slide the further core 102 to a position where it is in blocking register, or partially in blocking register, with one or more of rings 107 of ventilation holes, such that further core partially or wholly blocks the ventilation, to thereby alter the ventilation and thus smoking experience. In other words, the smoker is able to 'block' some or all of the rows of ventilation holes because ventilating air cannot pass through the non-porous further core wrapper on the further core. It will be appreciated that there may still be some leakage of air into the filter; it is not the objective of the invention to create an airtight seal. When further corel 02 is slid to a downstream position, the pressure drop and filtration characteristics of the filter will differ compared to when further core 102 is in the upstream position shown in Figure 2, as will be appreciated by those skilled in the art. It will be appreciated that the movement of the further core 102 is reversible; the smoker may slide the further core 102 to a different position, or back to the original position, in a similar manner by pushing on or pinching the outside of the filter in the region of further core 102.

The wrapper (e.g. outer wrapper) 105 is resilient such that it retains or substantially retains its original shape after being squeezed.

The tobacco smoke filter 100 (and the overall filter cigarette to which it is attached) has a fixed length. In other words the filter 100(and the cigarette to which it is attached) has an end to end measurement along the longitudinal axis which is fixed, and does not change (e.g. when the filter is adjusted by the smoker by moving the further core).

It will be appreciated that filters such as those illustrated in Figures 1 and 2 may be made by methods well known in the art, by for example by longitudinally advancing a continuous flow of component filter rods (arranged appropriately, e.g. with component rods which will form the upstream and downstream cores spaced form each other with further cores located therebetween) to a wrapping garniture where a continuously advancing outer wrapper of transparent polypropylene is wrapped around the longitudinally advancing flow of component filter rods and fixed using a lapped and stuck seam (as is well known). An EVA anchoring adhesive may be applied to the longitudinally advancing wrapper to hold the filter rods which will ultimately form the upstream and downstream cores in place on/in the plugwrap. The anchoring adhesive is applied, for example, by a pulse spray method, to the inner surface of the advancing wrapper exclusively in localised areas/patches corresponding to those regions where component rods which will form upstream and downstream cores will be present, immediately before the wrapper enters the wrapping garniture of the cigarette filter making machine. The advancing wrapper is then applied to the filtering cores by the garniture whereby the localised areas of adhesive on the inner surface of the transparent wrapper come into contact with the component rods which will form upstream and downstream cores to form a cohesive bond between the wrapper and these component rods. It will be appreciated that anchoring adhesive is not applied to the inner surface of the wrapper in areas which will not come into contact with the component rods which will form the upstream and downstream cores. In other words anchoring adhesive is not applied to the inner surface of the transparent wrapper in areas which correspond to spaces between upstream and downstream cores, where the further cores are located (so the further cores are not fixed in place).

Claims

1. A tobacco smoke filter or filter element having a fixed length comprising a wrapper engaged around a downstream core of tobacco smoke filtering material and a further core longitudinally aligned therewith; wherein the further core is reversibly moveable relative to the wrapper along the longitudinal axis of the filter.

2. A tobacco smoke filter or filter element comprising:

a downstream core of tobacco smoke filtering material;

an upstream core of tobacco smoke filtering material spaced longitudinally of the downstream core;

a wrapper engaged around and joining the spaced upstream and downstream cores; and

a further core located between, and longitudinally aligned with, the downstream and upstream cores;

wherein the further core is reversibly moveable between the spaced upstream and downstream cores along the longitudinal axis of the filter.

3. A tobacco smoke filter or filter element according to claim 2 including a region of ventilation between the spaced upstream and downstream cores.

4. A tobacco smoke filter or filter element according to any preceding claim wherein the wrapper includes a region of ventilation.

5. A tobacco smoke filter or filter element according to claim 3 or claim 4 wherein the region of ventilation comprises at least one ring or annulus of ventilation holes around the circumference of the filter/filter element.

6. A tobacco smoke filter or filter element according to any preceding claim wherein the wrapper is transparent.

7. A tobacco smoke filter or filter element according to any preceding claim wherein the wrapper comprises polypropylene, for example orientated polypropylene, biaxially orientated polypropylene; or cellophane.

8. A tobacco smoke filter or filter element according to any preceding claim wherein the downstream core and/or upstream core (if present) are adhered to the wrapper.

9. A tobacco smoke filter or filter element according to any preceding claim wherein the further core comprises a tobacco smoke filtering material.

10. A tobacco smoke filter or filter element according to any preceding claim wherein the tobacco smoke filtering material for each core is individually selected from a natural or synthetic filamentary tow, e.g. of cotton or plastics such as polyethylene or polypropylene, or cellulose acetate filamentary tow; a natural or synthetic staple fibre; cotton wool; web material such as paper (usually creped) and (e.g. synthetic) non-wovens; and extruded material (e.g. starch, synthetic foams, extruded foams).

11. A tobacco smoke filter or filter element according to any preceding claim wherein one or more of the downstream filtering core, the further filtering core and the upstream filtering core (if present) includes a flavouring agent.

12. A tobacco smoke filter or filter element according to any preceding claim wherein one or more of the downstream filtering core, the further filtering core and the upstream filtering core (if present) is coloured or tinted, and/or includes a coloured or tinted wrapper.

13. A tobacco smoke filter or filter element according to any preceding claim wherein one or more of the downstream filtering core, the further filtering core and the upstream filtering core (if present) includes an additive.

14. A tobacco smoke filter or filter element according to any preceding claim wherein the further core is moved by the smoker by pushing or pinching on the wrapper,

15. A tobacco smoke filter or filter element substantially as hereinbefore described with reference to Figure 1 or Figure 2.

16. A filter cigarette comprising a filter according to any preceding claim, or a filter which includes a filter element according to any claim, joined to a wrapped tobacco rod.

17. A filter cigarette according to claim 16 wherein filter is joined to the wrapped tobacco rod by ring tipping or a transparent full tipping overwrap.

18. A multiple rod comprising a plurality of filters or filter elements according to any of claims 1 to 15 integrally joined end-to-end in a mirror image relationship.