Enhancing the Disintegration and/or Degradation of a Smoking Article

Abstract

A filter (2) for a smoking article (1) is provided by the present invention, the filter comprising a vehicle containing a liquid capable of enhancing the disintegration and/or dispersibility of the smoking article. A method of enhancing the disintegration and/or degradation of a smoking article is also provided, wherein the smoking article comprises a vehicle containing a liquid capable of enhancing the disintegration and/or degradation of the smoking article.

Description

The invention relates to enhancing the disintegration and/or degradation of used smoking articles, and particularly, but not exclusively, to enhancing the disintegration and/or degradation of the filter of such smoking articles.

A problem with currently available tobacco smoke filters, particularly cigarette filters, is that they can be difficult to dispose of after use.

During smoking most of the tobacco rod and its circumscribing paper wrapper are converted to gases and ash in an incineration process. The remaining components of the spent smoking article include a small portion of ash, part of the original tobacco rod and wrapper, and the filter which is made up of the filter plug, plugwrap, and tipping paper wrapped about the tobacco rod and filter. There are also adhesives present that secure these components together. Spent smoking articles are generally completely dissociated into their individual constituent parts within a relatively short period of time when exposed to moisture, and/or mechanical abrasion. The individual components of the spent smoking articles are thus subsequently able to disperse and degrade.

The plug of filter material, however, typically does not readily disperse or degrade. With limited exceptions, filters are presently formed from highly crimped cellulose acetate fibres bonded at their contact points using plasticizers to provide a significant volume of interstitial space for the passage of smoke. The bonded contact points of such filter elements degrade very slowly under normal environmental conditions. The cellulose acetate fibres are themselves generally poorly biodegradable.

Despite the developments to date towards improving the biodegradability of filter plugs, there is interest in improved techniques for producing filters having an enhanced biodegradation rate. At the same time, there is also a need to retain the filtration chemistry, smoke characteristics and consumer acceptability provided by currently available smoking article filters.

In order to produce smoking articles, including filter cigarettes, which are more easily disintegrated or dispersed and are more biodegradable, it is desirable to provide a smoking article displaying a relatively rapid dissociation of the individual components of the spent smoking article followed by a good rate of dispersion and biodegradation of the individual components. In other words, increasing the rate of dissociation of a spent smoking article enhances the rate of degradation by increasing the exposure of the individual components to natural elements such as moisture, sunlight, mechanical abrasion, and aerobic biodegradation.

One approach that has previously been used to improve the dissociation of spent smoking article filters involves the incorporation of water expandable gels in the filter material to swell the filter upon contact with moisture and thereby break open the filter tipping paper to expose the filter material to the elements.

It has also been suggested to manufacture the components of a smoking article filter, including the filtration material, the filter plugwrap, and the tipping paper, from a moisture disintegrative paper. The use of water soluble adhesives for securing the filter plug and tipping paper wrappings is also known.

All of these approaches to improving the degradation of smoking article filters require the presence of water, such as moisture from rain, snow, dew, or residual moisture from those elements, for example, moist soil. However, in arid countries with little rainfall, such approaches are unlikely to be effective.

A further problem is that the cellulose acetate tow commonly used as filter material is not readily degradable or biodegradable. Thus, despite efforts to promote the dissociation of the spent smoking article, the filter material itself will not subsequently degrade. Therefore, much of the effort expended to reduce the environmental burden of spent smoking articles or to make such spent smoking articles more environmentally compatible has been directed to improving the biodegradability of the cellulose acetate fibres. Water soluble polymers have been used instead of triacetin which solvent bonds the cellulose acetate fibres typically used to make filters. Alternatively, soluble polymeric materials such as polyvinyl alcohol and ethylene vinyl alcohol copolymers may be used in place of cellulose acetate. Meanwhile, a tobacco smoke filter made of a creped paper manufactured from a wood pulp sheet and a tobacco filter made from a regenerated cellulose fibre bundle are also known. Compared with a filter comprising a cellulose acetate fibre bundle, these filters disintegrate slightly more readily when exposed to moisture.

While there are clearly environmentally preferable alternatives to cellulose acetate, degradability again generally depends on the presence of moisture, which as mentioned previously, may be scarce in some areas.

In light of the above, at least one embodiment of the invention provides a smoking article having enhanced disintegration, dispersion and/or degradation. In particular, at least one embodiment of the invention provides a filter for a smoking article which is capable of degrading in the absence of environmental water.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a filter for a smoking article is provided which comprises a vehicle containing a liquid capable of enhancing the disintegration and/or degradation of the smoking article.

The vehicle, which can be a capsule, may be broken or otherwise actuated to release the liquid immediately prior to disposal of the smoking article, or may be broken or otherwise actuated at a later time following disposal. Generally the vehicle is arranged to be actuated to release the liquid after the smoking article has been smoked.

The vehicle can be arranged to be actuated by a longitudinal or bending force acting on the filter, such that, for instance, the action of ‘stubbing out’ the smoking article acts to release the liquid. The process of actuation of the vehicle to release the liquid may substantially deform the filter.

The liquid may enhance the degradation of the smoking article in one or more of the following ways. Firstly, the various components of the smoking article may be induced by the liquid to dissociate, resulting in their increased exposure to the environment and accelerated dispersion and biodegradation. Secondly, the degradation of one or more of the components of the smoking article may be directly enhanced by the liquid. For example, the filter may comprise a filter material which may be degraded by the liquid carried in the vehicle. Thus, for instance, when a capsule containing the liquid is broken, the liquid is released, and the degradation of the filter material is enhanced.

According to a second aspect of the present invention, a smoking article comprising a filter as described herein is provided.

According to a third aspect of the present invention, the use of a capsule containing a liquid for enhancing the disintegration and/or degradation of a smoking article is provided.

According to a fourth aspect of the present invention, a method of enhancing the disintegration and/or degradation of a smoking article is provided wherein the smoking article comprises a capsule containing a liquid capable of enhancing the disintegration and/or degradation of the smoking article.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is made to the accompanying schematic drawings which each illustrate a longitudinal cross-section of an individual filter cigarette comprising a filter according to embodiments of the invention (not to scale).

FIG. 1 shows a filter according to one embodiment of the present invention.

FIG. 2 shows a filter according to an alternative embodiment of the present invention.

DETAILED DESCRIPTION

The present invention provides a filter for use in a smoking article, comprising a vehicle containing a liquid capable of enhancing the disintegration, dispersion and/or degradation of the smoking article. The vehicle is preferably resistant to manipulation during use of the smoking article, and is intended to be actuated upon disposal of the smoking article to release the liquid contents into the filter. The disintegration and degradation of the filter may occur directly, for example, by the dissolution or dispersion of one or more of the components of the filter, such as the filter material, in the liquid. Alternatively, the enhancement of degradation may be indirect, for example, as a result of increased environmental exposure resulting from the accelerated dissociation of the filter by the liquid.

FIG. 1 shows a smoking article 1 comprising a filter 2. The filter 2 comprises two sections of substantially cylindrical filter plug 3, separated by a cavity 6. The filter plug and cavity are wrapped in a plugwrap 4. A capsule 5 comprising a liquid is situated within the cavity 6 of the filter 2. The smoking article further comprises a cylindrical rod of smokeable material 7 aligned with the filter 2 such that the end of the smokeable material rod 7 abuts the end of the filter 2. The rod is wrapped in a paper wrapper 8, and is joined to the filter 2 by tipping paper 9 in a conventional manner.

FIG. 2 shows an alternative embodiment in which corresponding features have the same reference numerals. This embodiment differs from that shown in FIG. 1 in that the capsule 15 is elongate in shape. In addition, rather than being positioned with a cavity within the filter 2, the capsule 15 is embedded within the material of the filter plug 13.

The liquid held within the capsule is capable of enhancing the degradation of the smoking article. Consequently, the selection of the liquid is dependent upon the composition of the materials comprising the remainder of the smoking article and vice-versa. In a preferred embodiment of the invention, the liquid is water and various components of the smoking article are water-dispersible or wet-degradable to some extent as outlined below. In this way, the degradation of the smoking article is enhanced relative to an identical smoking article lacking a water-containing capsule.

In the embodiment shown in the FIG. 2, the capsule 15 is enclosed within the filter material 13. In some embodiments, the filter may be a composite filter comprising multiple filter segments. For example, the filter shown in FIG. 1 comprises two sections of filter material 3 separated by a cavity 6, which contains the capsule. In further embodiments, the capsule may be located in a cavity formed between the filter material and the rod of smokeable material, or the filter may comprise more than two filter sections, and may even include multiple cavities.

In the embodiments shown in the figures, the smoking article comprises a single capsule. In alternative embodiments, however, more than one capsule may be used, and in such embodiments, the capsules will generally be held within a cavity section formed in a multi-section filter.

The capsule may be inserted into the filter using any suitable method, and various methods of capsule insertion will be known to the skilled person. Suitable apparatus may, for example, include a means for supplying a continuous stream of filter material from a source of such material (e.g., a bale, bobbin, or the like). The apparatus may further include a capsule insertion unit for inserting or depositing the individual capsules at predetermined intervals within the filter material. The filter material having capsules deposited therein may then be received into a rod-making means for providing a continuous rod which may subsequently be subdivided into the desired length at predetermined intervals to form the individual filters of the invention.

Generally, prior art disclosures of capsules for use in smoking article filters are concerned with providing encapsulation methods aimed at releasing the encapsulated material before smoking occurs. The capsules are designed to resist breakage only during transport and storage, when the filter is not generally subject to significant external pressure. The capsule is subsequently intended to be ruptured immediately prior to use of the smoking article, and since this is the first exposure of the smoking article to significant manipulation and external pressure, the capsule is not necessarily required to be particularly robust.

In contrast, capsules for use in the invention are intended to be broken after the smoking article has been smoked, and thus are preferably capable of tolerating a significant degree of manipulation as the smoking article is smoked. Consequently, the capsule of the present invention should be more robust than those generally described in the prior art. It is important that the capsule is not accidentally ruptured before the smoking article is ready to be discarded. Such premature rupture could lead to the filtration characteristics of the smoking article being changed and deliveries being thereby altered compared to what is expected.

On the other hand, it is important that the capsule is not overly robust as it should be easily breakable after smoking ceases, during the manual extinguishing process or ‘stubbing out’. The capsule for use in the present invention may, for example, have a crush strength of between 1.5 and 2.5 kp, preferably between 1.7 and 2 kp.

The capsule may be designed and inserted into the filter in such a way that the capacity to rupture is dependent upon the nature of the pressure exerted. Pressure exerted by the user during smoking will predominantly be exerted by the fingers and mouth to the circumferential surface of the smoking article (“transverse” pressure). In some embodiments of the invention, the capsule is to be relatively resistant to transverse pressure to prevent premature rupture. On the other hand, the stubbing out process is likely to involve the application of “longitudinal” pressure along the length of the smoking article, and consequently the capsule should demonstrate a relatively reduced resistance to breakage in response to longitudinal pressure.

This directional capsule resilience may be achieved in a number of ways. For example, the capsule may be elliptical or ovoid and consequently demonstrate an increased resistance to rupture when pressure is exerted in one direction versus another. Alternatively, directional resilience may be achieved using a capsule which has been specifically strengthened in certain areas. Such a capsule may be produced, for example, having an increased shell thickness in selected areas. Naturally, a similar effect may be achieved by weakening the capsule wall in certain areas, to facilitate breakage or rupture in response to force being applied in a particular manner or direction.

The stubbing out process can also involve bending of the filter. Therefore, in some embodiments the capsule is designed to demonstrate increased susceptibility to rupture when the filter is bent or buckled. For example, a long cylindrical capsule may be used which may be ruptured by being snapped. Such elongate capsules will be positioned longitudinally within the filter, so that they are easily bent and ruptured when the filter of the smoking article is stubbed out and bent.

Various means of encapsulating substances, particularly liquids, for release in smoking article filters are known, and are generally suitable for use in the invention. Clearly, one of the primary considerations is that the capsule should generally be resistant to the degrading action of the intended contents. The capsule should also comprise material which has a melting point above the temperature of the smoke within the filter.

The capsule may exhibit brittleness under stress and/or may comprise a line of weakness, such as a scored line, a brittle point, or a weak section. Alternatively, a piercing means may be incorporated within the filter.

In preferred embodiments, the capsule is constructed from a frangible material. In one embodiment the capsule is composed of a low solubility, high molecular weight polyvinyl alcohol. A number of suitable alternative materials are known, and by way of example, capsules typically utilized in the pharmaceutical industry may be used. Such capsules may be gelatin based, for example, or may be formed from a polymeric material, such as modified cellulose. One type of modified cellulose which may be used is hydroxypropylmethyl cellulose. Many biodegradable materials are known which may be suitable for use in the production of capsules and these include high molecular weight polyethylene glycols, polylactic acid, plastarch material, polycaprolactone, polyglycolide, a polyhydroxyalkanoate such as poly-3-hydroxybutytate, and zein-derived bioplastics.

Alternatively, the capsule may comprise a length of thin-walled glass tubing, the ends of which may be sealed by heating or with a material capable of withstanding manual handling prior to and during smoking, yet which can be fractured after smoking. Other suitable materials include thin-walled aluminium tubing or hollow foodstuff material, such as, for example, pasta, or extruded hollow tubing of reconstituted tobacco material. The inner walls of the capsule material may advantageously be coated with a varnish or waterproof material, such as silicone, to preserve the rigidity of the capsule material by preventing absorption of, or degradation by, the liquid contents over a prolonged period.

The capsule may alternatively be comprised of a wax, resin, natural or synthetic gum, latex or plastic material which retains its shape and strength at room temperature and at smoking temperature but which fractures to release the liquid contents upon pressure applied to extinguish the smoking article. Examples of suitable waxes include beeswax, candelilla, carnauba, Shellac wax, caranday, sugarcane wax, myrtle wax and petroleum wax.

Suitable resins include epoxy resins, terpene resins, petroleum resins, ester gum, phenolic resins and rosin based resins. Preferred gums include gum arabic, locust bean, guar, alginates, carrageenan and pectin.

Preferably the substances comprising the capsule have no effect on the taste of the mainstream smoke as smoking occurs.

The capsule may be formed in a variety of physical formations including singular part or multipart capsules, large capsules, small capsules, microcapsules, etc. A number of different capsule configurations are suitable for use in the invention; for example, the capsule may be generally spherical (as shown in FIG. 1), ovoid, ellipsoidal (as shown in FIG. 2), cylindrical, or may approximate to a polygonal prism in shape.

The capsule may be coloured. For example, the capsule may comprise a colouring agent. The colouring agent may be used to render more easily the location of the capsule within the filter during the manufacturing process. Alternatively or additionally, the colouring agent may provide an interesting and attractive appearance to the smoking article, particularly if the capsule or capsules are intended to be only partially enclosed within the filter material, or if the tipping paper is intended to have a transparent window portion.

Alternatively or in addition, the liquid held in the capsule may be coloured. This would give the user an additional, visual indication that the liquid has been successfully released and that degradation of the spent smoking article will be enhanced. A coloured liquid also has the added benefit that it could act as an indicator when the capsule is accidentally ruptured before smoking. The colour would be a warning to the smoker that the smoking article has been damaged and should not be smoked.

The size of the capsule is clearly dependent on the volume of liquid required, but consideration should be given to the fact that the presence of the capsule in the filter should not have an adverse effect on the filtration or draw characteristics of the filter.

In one preferred embodiment, the capsule is 5 mm in diameter. Generally, the diameter of the capsule may be up to 80% of the diameter of the smoking article. Preferably the capsule diameter is up to 70%, up to 60%, or up to 50% of the diameter of the smoking article. For example, the diameter of the capsule may be between 2 and 7 mm, and preferably the diameter is between 4 and 6 mm.

The capsule should be large enough to accommodate sufficient contents to enhance the degradation of the smoking article. The volume required will vary according to the nature of the liquid held within the capsule, the composition of the remainder of the smoking article and the associated capacity of the liquid to enhance the degradation of the smoking article. The volume of the capsule may be up to 60%, up to 50%, up to 40%, or up to 30% of the total volume of the filter. The requirement for a large volume of liquid should be balanced, however, with the need to retain sufficient filter material within the filter to provide the required degree of filtration.

While it is preferable for the volume of the capsule to be as large as possible, as the size of the capsule is increased, the risk of premature breakage of the capsule is also increased. Furthermore, the larger the capsule, the greater is the obstruction to the smoke flow path. Consequently, to accommodate the required amount of liquid, it may be preferable for the filter to comprise two, three, four or more capsules. Multiple capsules may be positioned, for example, at regularly spaced intervals along the length of the filter. Alternatively, multiple capsules may be situated as a cluster within the filter, for example within a cavity formed between two sections of filter material.

Alternatively, long cylindrical or ellipsoidal capsules (or tubes) may be used, having a length equal to a significant proportion of the length of the filter, or even equal to the entire length of the filter. Such capsules may be up to 5 mm in diameter.

Multiple capsules may be used comprising different liquids.

In some embodiments, the capsule or capsules may be further encapsulated in a second capsule, or a sheath, or the like. This may allow greater protection from accidental or premature breakage, or incidental leakage. In this way, single wall or multi-wall capsules may be used to tailor capsule stability, strength, rupture resistance, processing ease in filter making, etc.

The capsule may be manufactured using any suitable method, the method of manufacture of the capsule clearly being dependent on the precise composition and make-up required. Various methods of capsule manufacture will be known to the skilled person, including techniques such as co-extrusion, spin coating, coacervation, interfacial polymerization, solvent evaporation, and annular jet forming.

In some embodiments in which the capsule is a seamless capsule, the capsule may be produced using a co-extrusion process. The co-extrusion process is a synchronous extrusion of the two liquids that will subsequently form the shell and the capsule contents (or “core”). The first (co-extrusion) step involves forming a droplet having the liquid core material inside the liquid shell material. After the co-extrusion step, the “capsule” is solidified by cooling or by immersion in a curing agent, for example. The capsules may then be subjected to various treatments, such as washing, removal of surplus liquid, colouring, application of additional coatings, etc.

Alternatively, an annular jet forming technique may be used. This method utilises two concentric jets to eject an inner jet of liquid core material and an outer jet of liquid shell material. The fluid stream breaks into droplets and the liquid shell material solidifies by phase transition induced by the presence of cross-linking ions, pH differences, temperature changes, etc.

In some embodiments in which the capsule comprises a wax capsule, the capsule may be formed, for example, by a method comprising freezing a solution of the liquid core material until small crystals are formed. According to this method, the crystals are then dropped into molten wax and removed by spatula after a wax coat has formed around the cold crystals. The frozen core material gradually becomes liquid as the coated capsule reaches room temperature.

In alternative embodiments, the capsule may be manufactured in situ. For example, in embodiments in which the capsule comprises a long cylindrical capsule extending the entire length of the filter, the capsule may be constructed by crimping a continuous tube into filter-length fragments as part of the filter manufacturing process.

The liquid held within the capsule may be any liquid capable of enhancing the degradation of one or more of the materials comprising the remainder of the smoking article. Clearly the nature of the liquid is dependent upon the composition of the materials of the smoking article and vice-versa.

The disintegration and/or degradation of the smoking article may be enhanced in one or more of the following ways. Firstly, the dissociation of the smoking article may be enhanced, resulting in the individual components having greatly increased exposure to the environment and thus being susceptible to accelerated degradation. Secondly, the degradation of one or more of the individual components may be directly enhanced, for example one or more of the components may be soluble or otherwise reactive with the liquid held within the capsule.

Smoking articles generally comprise a number of different papers (tipping paper, plugwrap, and tobacco wrapping paper) which bind the various components of the smoking article and hold them together. In some embodiments, the dispersion of the adhesive which binds these papers, and/or the papers themselves is enhanced by the action of the liquid in the capsule. In one preferred embodiment the liquid is water, the adhesive is a water-soluble or a water-dispersible adhesive, and the plugwrap and tipping papers comprise moisture disintegrative papers. Thus, when the capsule is ruptured, the water acts on the adhesive, the plugwrap, and the tipping paper, enhancing the dissociation of the smoking article and accelerating the environmental degradation of the various components of the smoking article.

There are a number of means by which the liquid may enhance the degradation of the smoking article. When the capsule is ruptured, the liquid is released and is able to migrate throughout the smoking article. In some embodiments, the liquid held within the capsule is an aqueous solution, and one or more of the remaining components of the smoking article are in some way water-degradable, for example, composed of water-soluble or water-dispersible material. In one embodiment, the liquid within the capsule is water, and the filter material is a water-soluble or water-dispersible material, such as polyvinyl alcohol.

In alternative embodiments, other liquids may be used in the capsule, and clearly the selection of liquid to be used is dependent on the composition of the other components of the smoking article.

Generally the preferred liquids for use in the capsule are aqueous solutions, and the most preferred liquid is water. Weak acidic or basic solutions may be used. In general, any liquid may be used that is not potentially toxic or harmful to the user. In case of the accidental premature breakage of the capsule, it is also important that none of the other components of the smoking article degrade to yield products which are potentially toxic or harmful to the user.

The liquid may be coloured. This may serve as a visible indication that the capsule has been ruptured, which may be important for two reasons. Firstly, this will inform the user if the capsule is prematurely broken, thus alerting the user that the smoking article should not be smoked. Secondly, when the user is attempting to break the capsule, this will serve as confirmation to the user that the capsule has indeed been satisfactorily ruptured. The interesting possibility of observing a coloured liquid may also serve as an incentive to encourage users to break the capsule upon disposal of the smoking article.

In some embodiments, the degradation of the smoking article is enhanced by means of a chemical reaction between the liquid and one or more of the remaining components of the smoking article, such as the filter material. The chemical contained within the capsule may be selected to react specifically with the particular component of the smoking article. Alternatively, the chemical may show a less selective capacity to chemically react with and degrade the smoking article, for example the chemical may be a weakly acidic solution.

The filter may comprise two or more capsules containing different liquids. The different liquids may react together or otherwise combine to form a liquid capable of enhancing the degradation of the smoking article. Alternatively, different components of the smoking article may be subject to degradation by different liquids.

In some embodiments, the capsule contains a solution which acts as an attractant to microorganisms, insects, or other organisms. Thus, the rate of degradation of the smoking article is effectively enhanced by the action of the living organisms.

According to these embodiments, the capsule may contain an environmentally acceptable aqueous solution of, for example, glucose (or other sugar solution), salt (as a saline solution), or starch (as a thin corn starch syrup). The skilled person will be aware that in all of these embodiments the selection of the materials comprising the reminder of the smoking article is important to promote the action of the microorganisms.

The capsule is intended to be ruptured upon disposal of the smoking article, and frequently, spent smoking articles are associated with undesired odours. Therefore, in addition to the degrading action, the liquid may additionally possess deodorising qualities. Alternatively, individual degrading and deodorising liquids may be incorporated into the filter in separate capsules, to be ruptured simultaneously.

The deodorising agent may be a neutralising agent or a masking agent, or be a combination of neutralising and masking agents.

Preferred deodorisers include 2-trans-3,7-dimethyl-2,6-octadien-8-ol (often known as geraniol), 1-carvone, 1-carveol, terpinyl acetate, geranyl propionate, citronellyl butyrate, citral, cis-3-hexenol, triacetin, benzyl benzoate, acetone, safrole, terpinyl propionate, methyl salicylate, hexyl cinnamic aldehyde, isopropyl alcohol, triethylglycol diacetate (TEGDA), OdorGone™, methyl cinnamaldehyde, linalyl propionate, acetic acid, citronellal, citronellyl formate, geranyl formate and linalool. Mixtures of these compounds are also suitable. Many other masking agents, such as perfumes, e.g. essential oils used in pot pourri, are also suitable compounds for use in the present invention.

The filter material used in the filters of the vast majority of currently available smoking articles is composed of cellulose acetate fibres and does not readily disintegrate or biodegrade.

The filter material of one embodiment of the invention is composed of polyvinyl alcohol. Polyvinyl alcohol is commercially available as a thermoplastic, water soluble, solid polymer that is relatively inexpensive and non-toxic. Polyvinyl alcohol is unique in being the only biodegradable, carbon-carbon backbone polymer capable of complete biodegradation under environmental conditions. Thus, in the embodiment shown, when the spent smoking article is discarded, the user ruptures the capsule, for example by squeezing the filter, or by stepping on the spent smoking article. This releases the water contained within the capsule, which migrates throughout the filter, and promotes the degradation of the polyvinyl alcohol filter material.

In alternative embodiments, other water-degradable substances may be used, such as starch, ethylene vinyl alcohol copolymers, polylactic acid, creped paper manufactured from a wood pulp sheet, or a regenerated cellulose fibre bundle.

As described above, the liquid may not act to dissolve the filter material, but may enhance the degradation of the smoking article via some other mechanism. For example, in some embodiments, the filter material may be cellulose acetate which has been manufactured using a water-soluble plasticizer to bind the cellulose acetate fibres. According to these embodiments, the liquid may be water, and other components, such as the plugwrap, tipping paper, and/or adhesive, may also preferably be water-soluble or water-dispersible. Consequently, rupture of the capsule results in dissociation of the components of the filter, including dispersion or dissolution of the plasticizer. As a result, the cellulose acetate fibres are no longer bound to one another and the filter material disintegrates and the individual cellulose acetate fibres are able to disperse. As an alternative to the use of a water-soluble plasticizer, non-woven or loose processed cellulose acetate fibres may be used.

In embodiments in which the liquid promotes the dissociation of the components of the smoking article, the filter may further comprise a material or powder which is capable of expansion upon the action of the liquid. In this way, rupture of the capsule results in expansion of this substance and consequent rupture of the filter. Suitable materials capable of expansion will be known to the skilled person. For example, materials which will swell upon contact with water include carboxymethyl cellulose, water-dispersible starch, chemically modified starch, and super absorbent polymers such as a cross-linked copolymer of acrylic acid and sodium acrylate or a cross-linked copolymer of acrylamide and potassium acrylate. These materials may be incorporated into the filter, for example in powder form, and will swell when exposed to water, for example water from the capsule of the invention. The swelling action physically separates the components of the filter, enhancing disintegration of the structure and dispersion of the components.

In other embodiments, the liquid may be an aqueous solution comprising biological agents capable of degrading the cellulose, such as cellulase enzymes.

In some embodiments, the filter material may comprise paper. The liquid may be water, which will not dissolve paper but will nevertheless enhance its disintegration and degradation.

Filter materials may be used which are not biodegradable per se but may be disintegrated or converted into a biodegradable form by the action of a particular chemical held within the capsule.

Many smoking articles are configured to entrain a flavourant within the smoke that is drawn along the smoking article by the user. This is frequently achieved by the incorporation of flavourant-containing capsules within the smoking article filter. In such smoking articles, encapsulation prevents the volatile flavourant from evaporating prematurely, with the capsule being ruptured to release the flavourant prior to use of the smoking article. This method of flavouring smoking articles is not obviously compatible with the degradable smoking articles described herein, however. This is due to the abundance of capsules that would be required in the filter, and the fact that the flavourant capsules should be ruptured prior to smoking, whereas the capsules of degrading liquid should be broken upon disposal of the spent smoking article.

Consequently, in some embodiments of the present invention, the filter may comprise a thread passing along a longitudinal axis of the filter from the tobacco rod end to the mouth end. According to these embodiments, the threads are loaded with aromatic or flavourant material. Thus, as smoke is drawn along the smoking article, flavourant held within the thread becomes entrained in the smoke. The use of a flavourant-enriched thread also provides a simple means of incorporating flavourant into the smoking article filter, requiring minimal modification of the manufacturing process.

As used herein, the term “flavour”, “flavouring”, and “flavourant” refer to materials which may be used to create a desired taste or aroma. Preferred flavourants include extracts (e.g., licorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint, peppermint, lavender, cardamon, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger, anise, coriander, coffee, or a mint oil from any species of the genus Mentha), flavour masking agents, bitterness receptor site blockers, receptor site enhancers, sweeteners (e.g., sucralose, acesulfame potassium, aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose, sorbitol, or mannitol), and other additives such as chlorophyll, minerals, botanicals, or breath freshening agents. They may be imitation, synthetic or natural ingredients or blends thereof.

The preferred material for the manufacture of the thread is cotton, although other materials such as cellulose acetate and rayon, or natural materials such as plant fibres, may also be used. According to these embodiments, the liquid held within the capsule may be capable of degrading the flavourant-enriched thread.

In some preferred embodiments of the present invention, moisture disintegrative papers are used as the plugwrap, tobacco wrapping paper and tipping paper. Thus when the capsule is ruptured, water is released, and the degradation of the paper wrappers is enhanced, promoting the dissociation of the smoking article.

In alternative embodiments, one or more of the papers used in the smoking article may not be disintegrated by water, but may be otherwise biodegradable. In other embodiments, one or more of the papers are not biodegradable per se but may be disintegrated by the action of a particular chemical held within the capsule, such as a weakly acidic solution, for example.

In order to produce an unusual visual effect, in some embodiments, the filter comprises a transparent window which allows visualisation of the filter material and/or capsule within the filter. In some such embodiments, the capsule is held in a cavity formed between two pieces of filter material and the transparent window is aligned with the cavity section of the filter material. In this way the user is provided with the unusual effect of being able to visualise the capsule within the filter, and this may serve as a reminder to break the capsule once the smoking article has been smoked. To produce the effect of a transparent window, the tipping paper may comprise a single piece of transparent material, which can be, but is not limited to, one of polypropylene, polyvinyl chloride (PVC), cellulose acetate film, polyethylene terephthalate (PET), polyethylene oxide (PEOX), polyethylene, cellophane, Natureflex™, polylactic acid, plastarch material, polycaprolactone, polyglycolide, a polyhydroxyalkanoate such as poly-3-hydroxybutyrate, and zein-derived bioplastics. The tipping paper has an opaque coating on certain portions to leave a transparent uncoated section which defines the window. Since the material will be in contact with moisture from the user's mouth and fingers, the transparent material used is either insoluble, or is treated with a water-resistant external coating. According to these embodiments comprising a transparent material, the liquid held within the capsule may be capable of degrading the transparent material.

Adhesive is generally used to bond the seams of the plugwrap, tipping paper, and cigarette paper of a smoking article. In preferred embodiments of the invention, water-soluble or water-dispersible adhesives are used. Water released from the capsule when it is ruptured causes loss of the bonding between the various components of the smoking article, resulting in the individual components having greatly increased exposure to the environment, and thus being susceptible to accelerated disintegration and biodegradation.

The preferred water soluble adhesives for the seam adhesives are liquid starch adhesives. Hot melt adhesives, or EVA and PVA adhesives may also be used.

In some embodiments, one or more of the adhesives used are not water soluble. In this case, a solvent is held within the capsule which acts to soften or solubilise the adhesive, promoting disintegration of the smoking article.

Although the vehicle containing the liquid capable of enhancing the disintegration and/or dispersion of the smoking article has been generally described above as being a capsule, other fluid-containing vehicles can be used. For instance, pockets or pouches formed directly within a filter material or from a separate material such as polyethylene could be used, to be ruptured once the smoking article has been smoked. Also, a sponge-like porous material such as a foamed plastic polymer could be used to contain the fluid, which could be released via a squeezing or twisting action once the smoking article has been smoked. Other suitable fluid-containing arrangements would be evident to those skilled in the art.

Above is described what is believed to be the preferred embodiment of the invention. However, those skilled in the art will recognise that changes and modifications may be made without departing from the scope of the invention a defined in the claims.

Claims

1. A filter for a smoking article comprising a vehicle containing a liquid capable of enhancing at least one of disintegration and degradation of the smoking article, and wherein the filter comprises filter material which is soluble, swellable or dispersible in water.

2. The filter according to claim 1, wherein the liquid is capable of enhancing dispersion of the smoking article.

3. The filter according to claim 1, wherein the vehicle comprises a capsule.

4. The filter according to claim 1, wherein the vehicle is arranged to be actuated to release the liquid after the smoking article has been smoked.

5. The filter according to claim 4, wherein the vehicle is arranged to be actuated by a longitudinal or bending force acting on the filter.

6. The filter according to claim 4, wherein actuating the vehicle to release the liquid substantially deforms the filter.

7. The filter according to claim 1, wherein the liquid enhances dissociation of components of the filter.

8. The filter according to claim 1, wherein the liquid is an aqueous solution.

9. The filter according to claim 8, wherein the liquid is water.

10. The filter according to claim 1, wherein the filter material is polyvinyl alcohol.

11. The filter according to claim 1, wherein the filter comprises a plugwrap, tipping paper and adhesive, and wherein one or more of these is soluble, swellable or dispersible in water.

12. The filter according to claim 1, wherein the vehicle comprises a biodegradable material.

13. The filter according to claim 1, wherein the vehicle comprises a capsule having a crush strength of greater than 1.7 kp.

14. The filter according to claim 1, wherein the vehicle comprises a capsule having a volume of no more than about 50% of the total volume of the filter.

15. (canceled)

16. A smoking article comprising a filter, said filter comprising a vehicle containing a liquid capable of enhancing at least one of disintegration and degradation of the smoking article, and wherein the filter comprises filter material which is soluble, swellable or dispersible in water.

17. (canceled)

18. A method of enhancing at least one of disintegration and degradation of a smoking article wherein the smoking article comprises a filter and a vehicle containing a liquid capable of enhancing at least one of the disintegration and degradation of the smoking article, and wherein the filter comprises filter material which is soluble, swellable or dispersible in water.