HK1140112A1 - Low sidestream smoke cigarette with combustible paper having modified ash characteristics - Google Patents

Abstract

A low sidestream smoke cigarette comprises a conventional tobacco rod, and a combustible treatment paper having a sidestream smoke treatment composition. The treatment composition comprises in combination, an oxygen storage and donor metal oxide oxidation catalyst and an essentially non-combustible particulate adjunct for said catalyst. Improvements are made in the treatment composition and/or the addition of metal oxides or carbonates thereto to improve ash characteristics.

Description

Low sidestream smoke cigarette made with combustible paper having improved ash characteristics

This application is a divisional application of PCT International application No. 03805997.5, entitled "Low sidestream Smoke cigarette made from combustible paper with improved ash characteristics", filed in China at 9/14.2004 (International publication No.: WO03/077687, International application date: 3/14.2003).

Technical Field

The present invention relates to cigarettes and other smoking articles that reduce sidestream smoke when combusted. More particularly, the present invention relates to cigarette paper, cigarette wrapper, or wrapper for a cigar or similar smoking article that provides improved ash while reducing visible sidestream smoke.

Background

Efforts have been made to reduce or eliminate sidestream smoke when burning a cigarette. Applicants have developed various sidestream smoke control systems for cigarettes, such as those described in Canadian patent Nos. 2054735 and 2057962, U.S. patent Nos. 5462073 and 5709228, and published PCT applications WO96/22031, WO98/16125 and WO 99/53778.

Other sidestream smoke control systems have also been developed using filter materials or sorbent materials in the tobacco, filter or wrapper. Examples of this are found in U.S. Pat. Nos. 2755207, 4108151 and 4225636, European patent application Nos. 0740907 and 0251254, WO97/27831 and WO 99/53778. U.S. patent No. 2755207 discloses a low sidestream smoke cigarette paper. The wrapper produces substantially no unpleasant components when burned. The cigarette paper is a cellulosic material in fibrous form. It is intimately mixed with a finely divided, ore-type siliceous catalyst material. The wrapper is substantially non-combustible and substantially maintains a constant fire resistance when the wrapper is combusted, and it acts like a catalyst in improving the combustion of the paper. Suitable siliceous catalysts include acid-treated clays, heat-treated montmorillonites, and natural and synthetic silicates containing certain relatively mobile hydrogen atoms. Suitable mixed silica oxides include silica oxides with alumina, zirconia, titania, chromia, magnesia. Other silicas include silica-alumina in a 9: 1 weight ratio of silica to alumina.

U.S. patent No. 4108151 discloses the use of gamma alumina filler in cigarette paper, which selectively reduces the organic vapor phase component upon combustion of tobacco. To reduce organic vapour phase constituents in tobacco smoke, at least 50% by weight of alumina filler is present in the wrapper. As a result, visible sidestream smoke emitted from a burning cigarette is reduced. The best known gamma alumina is activated alumina, which is finely ground to pass through a 300 mesh screen.

Us patent 4225636 discloses the use of carbon in cigarette paper to reduce the organic vapour phase constituents and total particulate matter formed in the side smoke. In addition, the carbon results in a substantial reduction in the visible side smoke emanating from a burning cigarette. Activated carbon is the preferred carbon source. The use of activated carbon resulted in a slight reduction in visible side smoke. Up to 50% finely divided carbon may be used in the wrapper. The carbon coated paper can be used as an inner wrapper for a conventional cigarette and tobacco rod combination.

European patent application No. 0740907, published 11/6/1996, discloses the use of zeolites in tobacco of cigarettes to modify the characteristics of the mainstream smoke, particularly to remove certain tars from the mainstream smoke. As zeolite is provided to the tobacco, it also significantly alters the lateral smoke characteristics. The zeolite used has a particle size of 0.5nm to 1.2 nm.

European patent application No. 0251254 describes the use of high specific surface area fillers in cigarette paper. Said fillers generally having a specific surface area of at least 20m²Crystals per g and solids. The fillers are preferably peroxides, carbonates, phosphates, sulfates, aluminates and silicates. It is taught that porous fillers such as zeolites are not preferred in cigarette paper and function similarly to conventional chalk.

Published PCT patent application No. WO97/27831 describes the use of dealuminate zeolites to absorb polar liquids or gases formed from non-polar or weakly polar molecules. An effective amount of powdered dealuminate zeolite may be mixed in the cigarette paper to reduce carbon monoxide in the side smoke. The dealumination step of the aluminous zeolite imparts hydrophobicity to the zeolite so as to affect absorption and removal of non-polar and weakly polar molecules that occur even in the presence of water.

Published PCT patent application WO99/53778 describes a treatment for non-combustible paper sheets to reduce side-to-side smoke emissions. The paper sheet is used as an envelope paper and is widely used as a conventional cigarette paper for a conventional cigarette. The wrapper has a very high porosity to allow the cigarette to burn at or near the normal natural burn rate while reducing visible side smoke emissions. The non-combustible wrapper comprises non-combustible ceramic fibres, non-combustible activated carbon fibres and other standard materials commonly used in the manufacture of cigarette paper. The encapsulating paper also includes a zeolite or other similar sorbent material and an oxygen donor/oxygen storage metal oxide oxidation catalyst. Although the non-combustible wrapping paper provides acceptable side smoke control, the burnt tube remains after combustion due to the non-combustibility of the wrapping paper.

U.S. patent nos. 4433697 and 4915117 describe the incorporation of ceramic fibers during the manufacture of cigarette paper. U.S. patent No. 4433697 discloses the presence of at least 1% by weight of certain ceramic fibers in a paper furnish in combination with a filler of magnesium oxide and/or magnesium hydroxide to reduce the lateral smoke visible from a burning cigarette. In a conventional paper machine a furnish consisting of fibrous pulp, ceramic fibres and fillers is used to make paper. The ceramic fibers may be selected from the group consisting of polycrystalline alumina, alumino-silicates, and amorphous alumina. Magnesium hydroxide or magnesium oxide fillers are used and they are coated on or applied to the fibrous sheet.

U.S. patent No. 4915117 describes a non-combustible sheet material for retaining tobacco. The sheet is formed of a ceramic material which does not produce smoke when burned. The ceramic sheet comprises a woven or non-woven fabric of ceramic fibers or a mixture of paper and ceramic that thermally decomposes at high temperatures. The ceramic fibers may be selected from inorganic fibers such as silica fibers, silica-alumina fibers, zirconia fibers, or aluminoborosilicate and glass fibers. The ceramic sheet is formed by bonding these materials with an inorganic binder such as silica gel or alumina gel. The diameter of the fibers is preferably 1 to 10 microns.

Published PCT patent application No. WO01/41590 describes the use of ceramic materials in cigarette wrapper paper to reduce side-effects. The ceramic filler incorporated in the cigarette wrapper using the adhesive has a diameter of 2 to 90 μm. The ceramic filler has a predetermined shape, including spherical or substantially spherical, elliptical or substantially elliptical or another irregular shape. The ceramic filler may be alumina, silica, boro-alumino-silicate, silicon carbide, stabilized or unstabilized zirconia, zircon, garnet, feldspar, and the like. The ceramic filler comprises greater than 40% by weight of the cigarette wrapper based on the weight of dry material of the papermaking stock used to produce the cigarette wrapper. The binders may be those of alginates, gums, celluloses, pectins, starches or salts of metals of group I or II of the periodic table. The wrapping paper typically has a porosity of less than 200 Coresta units, preferably from 2 to 100 Coresta units. The density of the wrapping paper is 0.5-3.0g/cm³. The wrapper is preferably used as a porous non-smoking article having a porosity of about 12000 Coresta unitsThe outer wrapping of the tobacco rod of the filter tip.

To reduce sidestream smoke sol gels, particularly those made from magnesium aluminate, calcium aluminate, titania, zircon and alumina, have been applied to conventional cigarette paper as described in canadian patent 1180968 and canadian patent application 2010575. Canadian patent 1180968 discloses the application of magnesium hydroxide in the form of an amorphous gel as a filler component of cigarette paper to improve the appearance of ash and reduce sidestream smoke. The magnesium hydroxide gel is coated on or applied to a sheet of cigarette paper. Canadian patent application No. 2010575, describes the use of gels produced by solution gelation or sol-gel processes to control the burning of the wrapper of a tobacco product. The wrapper is effective to reduce visible side-on smoke emissions. The metal oxide as a sol-gel may be an oxide of aluminum, titanium, zirconium, sodium, potassium or calcium.

Published german patent application DE 3508127 describes a novel cigarette which produces a spark burst when smoked. This is achieved by adding a particulate rare earth metal mixture (in the form of cerium ferrite or silicon-cerium) to the cigarette paper. When a cigarette is smoked, particularly in dark spaces, the burning cigarette emits a spark that produces a bright effect. The cerium ferrite particles incorporated into the cigarette paper typically have a particle size of about 20 μm.

The catalyst may also be applied directly to the cigarette paper as described in canadian patent 604895 and U.S. patent 5386838. Canadian patent 604895 describes the use of platinum, osmium, iridium, palladium, rhodium and ruthenium in cigarette paper. These metals act as oxidation catalysts to treat the vapors emanating from the paper wrapper when burned. The optimum catalytic effect can be provided by the metallic palladium. The metal particles in a suitable medium are dispersed onto the paper-wrapped side before it is applied to the cigarette.

Us patent No. 5386838 describes the use of a sol solution comprising a mixture of iron and magnesium as a smoke suppressant composition. The smoke suppressant composition is prepared by co-precipitating iron and iron from an aqueous solution in the presence of a baseMagnesium. The iron magnesium composition exhibits a temperature of up to about 100m when heated to a temperature of between 100 ℃ and about 500 ℃²A/g of about 225m²Surface area in g. The iron magnesium composition may be added to the pulp used to make the smoke suppression cigarette paper. The iron-magnesium composition acts as a significant oxidation catalyst and reduces the amount of smoke generated when burning a cigarette. The catalyst can also be used in tobacco, for example, as described in U.S. patent No. 4248251, palladium (either in metallic form or in the form of a salt thereof) can be applied to tobacco. The presence of palladium in tobacco reduces polycyclic aromatic hydrocarbons in mainstream smoke. Palladium is used with an inorganic salt or a nitrogen-containing acid or nitrous acid. Such nitrates include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, lanthanum, cerium, neodymium, europium, gadolinium, terbium, dysprosium, erbium, scandium, manganese, iron, rhodium, palladium, copper, zinc, aluminum, gallium, tin, bismuth, hydrates thereof, and mixtures thereof. The catalyst may also be used in a mouthpiece to reduce sidestream smoke as described in published PCT application WO 98/16125.

U.S. patent No. 6228799 describes a composition comprising cerium oxide and zirconium oxide in particulate form and having a particle size generally in excess of 35m²High surface area in g. The composition is prepared by co-precipitating cerium and zirconium from solution at high temperature, then separating and drying at a temperature between 80-300 ℃, and then calcining at a temperature between 200-1200 ℃.

The catalytic materials that have been used in cigarettes are aerosol-type, which do not produce sidestream and mainstream smoke per se, but may instead be flavoured aerosols. Examples of such aerosol cigarettes include those described in U.S. patent nos. 5040551, 5137034 and 5944025, which use a catalyst to provide the heat necessary to form the aerosol. Such catalyst systems include oxides of cerium, palladium or platinum.

The prior art has focused on various sidestream smoke control systems, but none of them has focused on combustible wrappers that burn like normal cigarettes without significantly affecting the taste of the cigarette, and whose ash content is acceptable.

Disclosure of Invention

In accordance with various aspects of the present invention, there is provided cigarette paper, cigarette wrapper, cigar or other similar smoking article wrapper for reducing visible sidestream smoke and improving ash content for cigars or other similar smoking articles.

In accordance with one aspect of the invention, in a low sidestream smoke cigarette having a conventional tobacco rod and a combustible treatment paper, said treatment paper having a low sidestream smoke treatment composition comprising an oxygen storage and donor metal oxide oxidation catalyst and a substantially non-combustible, finely divided particulate additive for said catalyst, the improvement comprising the use of a solid solution of a particulate mixed metal oxide as said catalyst and said additive.

The oxygen storage and donor/metal oxide oxidation catalyst as part of the solid solution is preferably selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide and mixtures thereof. The additive, which is also part of a solid solution, is preferably a metal oxide selected from the group consisting of zirconia, alumina, magnesia, titania and mixtures thereof.

The solid solution of mixed metal oxides may further comprise a solid solution metal catalyst selected from the group consisting of palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide, and mixtures thereof. Preferred mixed oxides of solid solutions are cerium/lanthanum mixed oxides, cerium/zirconium/lanthanum mixed oxides, cerium/zirconium/praseodymium mixed oxides, cerium/zirconium/lanthanum/praseodymium mixed oxides, cerium/zirconium/neodymium mixed oxides and mixtures thereof.

In accordance with another aspect of the invention, a low sidestream smoke cigarette having a conventional tobacco rod and a combustible treatment paper, wherein the combustible treatment paper has a sidestream smoke treatment composition comprising an oxygen storage and donor/metal oxide oxidation catalyst, a substantially non-combustible additive for said catalyst and a metal oxide for modifying ash characteristics.

According to yet another aspect of the invention, the additive may include a mixed metal oxide or carbonate filler used with the zeolite-based material. The preferred amount of zeolite-based material is about 0.1% to 35% by total dry weight of the composition, although this amount may be higher. The mixture of metal oxides may include zirconium oxide, tin oxide, titanium oxide, aluminum oxide, cerium oxide, tin oxide, iron oxide, manganese oxide, zirconium carbonate, magnesium carbonate, and mixtures thereof. The metal oxide may be of various surface areas, and most preferably may be as low as about 5-15m²Low surface area per gram, also up to about 20m²A high surface area of at least g. The ceria hydrate sol can be applied to an additive, e.g., a metal oxide, to provide increased catalytic activity.

According to yet another aspect of the present invention, the oxygen storage and donor/metal oxide oxidation catalyst preferably comprises lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, and mixtures thereof. Noble metal and transition metal type catalysts may also be included, such as palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide, and mixtures thereof. These catalysts may also be immobilized on additives or ash modifying materials or as part of a solid solution of mixed oxides.

The sidestream smoke treatment composition may be incorporated into the combustible treatment paper, coated onto the combustible treatment paper, impregnated into the treatment paper, or a combination of the various steps described above to apply the sidestream smoke treatment composition. The treated paper may be double-ply and of the same or different composition. One type of double wrap paper may be conventional paper. In addition, one double wrap paper may have a composition directed primarily to sidestream smoke reduction, while another double wrap paper includes a composition directed for ash modification.

According to yet another aspect of the invention, a low sidestream smoke cigarette comprises a conventional tobacco rod and a combustible treatment paper having a sidestream smoke treatment composition. The treatment composition comprises an oxygen storage and donor/metal oxide oxidation catalyst and a substantially non-combustible high surface area sorbent additive which is added to said treatment catalyst.

For convenience of description, whenever the term cigarette is used, it will of course include not only smoked cigarettes but also any form of wrapped smoking tobacco product, such as cigars and the like. Whenever the term treatment paper is used, it includes, of course, combustible wrapping paper that may be used for cigarettes, cigars, etc. The wrapper may be used as a single wrap or a multiple wrap. The wrapper may be used as a base layer of cigarette paper or as a conventional over-wrapped cigarette paper for a cigarette. The treatment paper may include as its substrate a conventional cigarette paper or similar combustible product having a wide range of porosity. Conventional tobacco rods include tobacco components commonly used in smoking cigarettes. These tobacco rods can be distinguished from the tobacco components of smoke cigarettes.

Drawings

Preferred embodiments of the invention are illustrated in the drawings, in which:

figure 1 is a schematic illustration of a spray process for applying a treatment composition to cigarette paper;

figure 2 is a schematic illustration of the extrusion of a film of the treatment composition onto cigarette paper;

figure 3 is a schematic illustration of roll coating the treatment composition onto cigarette paper;

figure 4 is a schematic illustration of the impregnation of a coating of the treatment composition into the cigarette paper;

figure 5 is a schematic illustration of the mixing of the treatment composition with the pulp in the manufacture of cigarette paper;

FIG. 6 is a perspective view of a tobacco rod having the treatment paper of the present invention therein;

FIG. 7 is an alternative embodiment of FIG. 6;

FIG. 8 is a perspective view of a tobacco rod applied to the tobacco rod with the treatment composition sandwiched between two layers of cigarette paper; and

figure 9 is a perspective view of a double wrap paper for tobacco filaments wherein the treatment paper is applied to the outside of a conventional cigarette paper.

Detailed Description

In accordance with one aspect of the present invention, a sidestream smoke treatment composition provides a desirable degree of visible sidestream smoke control while at the same time providing ash of desirable characteristics. The sidestream smoke treatment composition of the present invention comprises: oxygen storage and donor/metal oxide oxidation catalysts for use with non-combustible, finely divided porous particulate additives for the catalyst. As taught in applicant's U.S. patent application No. 09/954432 filed 2001, 9/18, it has now been unexpectedly found that these two components, when used by themselves or with other components, provide an unexpected and very surprising degree of visual sidestream smoke control. It has now been found that with certain types of catalyst materials and/or additives, ash characteristics, such as appearance, can sometimes be reduced to acceptable levels due to, for example, discoloration, delamination, and sloughing. The manufacture of compositions according to the present invention has been improved, particularly the manufacture of catalysts and/or additives that improve ash characteristics, providing acceptable appearance, acceptable strength, integrity, and reducing or eliminating ash fallout, delamination, and the like.

The additive may be any suitable substantially non-combustible, finely divided particulate material which does not affect the taste of the mainstream smoke and which does not emit undesirable odours in the sidestream vapours. The particulate material is physically stable at the high temperatures of burning cigarette coal. The additive may have a particle size of typically less than 20m²Low surface area per g, preferably 1m²/g-15m²G, most preferably 3m²/g-10m²(ii) in terms of/g. Of course, as a low surface area material, the particles are finely divided and generally not porous. However, e.g. low surface area increases to more than 20m²In terms of/g, the particles may, of course, generally be porous. Conversely, the additive may also have a particle size generally greater than 20m²A high surface area in g at which the particulate material is porous. The porous additive may have an average diameter of less than 100 nm: (). More preferably, the pores have a size of less than 20 nm: () And most preferably the pores have a diameter of 0.5nm-10nm (5-) Average diameter of (2). In the case of zeolite-based materials, the average diameter of the pores is about 0.5-1.3nm (5-)。

The particulate additive may have an average particle size of less than about 30 μm, more preferably less than about 20 μm, and most preferably from about 1 μm to 10 μm. The non-combustible material may be various porous clays commonly used in the manufacture of cigarette paper, such as bentonite clays or treated clays having a high surface area. Non-combustible materials that may also be used include ground porous carbon fibers and particles. Various oxides and/or carbonates may also be used, such as porous monolithic mineral-based materials, e.g., zirconia, titania, magnesia, alumina, ceria, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate, and mixtures thereof, metal oxide fibers, such as zirconium fibers, and other ceramics, such as milled porous ceramic fibers, and mixtures thereof. In the case of cerium oxide, it has been found that it can act as a finely divided additive and as an oxygen storage and oxygen donor/metal oxide oxidation catalyst. Other additive materials include high surface area materials such as activated carbon and zeolites.

The additive may also include a sorptive material which is a non-combustible, inorganic finely divided particulate, such as molecular sieves including zeolites, and may also include amorphous materials such as silica gel/alumina, zirconia, zirconium hydroxide, and the like. Zeolites such as silicalite, faujasite X, Y and L zeolite, beta zeolite, mordenite and ZSM zeolite are suitable. Preferred zeolites include hydrophobic zeolites and slightly hydrophobic zeolites which have an affinity for such hydrophobic and slightly hydrophobic organic compounds of sidestream smoke, whereby water vapour is avoided. The zeolite material provides a highly porous structure that is capable of selectively sorbing and sorbing components of sidestream smoke. The highly porous structure typically includes macropores in the particle and micropores separated from the macropores. It is believed that at the elevated temperatures of a burning cigarette in the presence of cerium oxide and other suitable oxidation catalysts, the components trapped in the macropores and micropores can be converted to oxidized compounds which either continue to be trapped in the sorbent material or are released as invisible gases with sufficiently low tar and nicotine content that the sidestream is invisible or at a low desirable level.

The zeolitic material may be characterized by the following formula: m_mM’_nM“_p[aAlO₂·bSiO₂·c T O₂]

Wherein

M is a monovalent cation of the group consisting of,

m 'is a divalent cation, and M' is a divalent cation,

m 'is a trivalent cation, and M' is a trivalent cation,

a. b, c, n, m and p are numbers reflecting the stoichiometric ratio,

c. m, n or p may also be zero,

al and Si are tetrahedrally coordinated Al and Si atoms, and

t is a tetrahedrally coordinated metal atom capable of substituting Al or Si,

wherein the zeolite or zeolite-like material has a b/a ratio of about 5 to 300 and a pore size of about 0.5 to 1.3nm (5-)。

Preferred zeolites of the above formula are those having the particular formula: faujasite ((Na)₂，Ca，Mg)₂₉[Al₅₈Si₁₃₄O₃₈₄]·240H₂O; cubic), beta-zeolite (Na)_n[Al_nSi_64-nO₁₂₈]N is less than 7; squares), mordenite (Na)₈[Al₈Si₄₀O₉₆]·24H₂O; orthogonal), ZSM zeolite (Na)_n[Al_nSi_96-nO₁₉₂]～16H₂O, and n < 27; orthogonal), and mixtures thereof.

Obviously, various grades of sorbent material can be used. This is true for sorption gradients of zeolites which are typically selective sorbents such as high boiling point materials, medium boiling point materials and low boiling point materials. This can result in the layers of the zeolite composition preferably having cerium oxide or other suitable catalyst of interest throughout the layers. These layers are then bonded to the wrapper of the tobacco rod by the use of an adhesive or bonding agent such as polyvinyl acetate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch and casein or soy protein, and mixtures thereof.

The oxygen donor/storage metal oxide oxidation catalyst may be selected from transition metal oxides, rare earth metal oxides (such as scandium, yttrium, lanthanite metal species, i.e., lanthanum), and mixtures thereof. It will be appreciated that the catalyst may be in the form of its metal oxide or a metal oxide precursor thereof which is converted to a metal oxide to fulfil its catalytic activity at the elevated temperatures of the burning cigarette. The transition metal oxides may be selected from the group consisting of oxides of metals of groups IVB, VB, VIB, VIIB, VIIIB and IB of the periodic table and mixtures thereof. Preferred metals from the transition metal group are oxides of iron, copper, silver, manganese, titanium, zirconium, vanadium, and tungsten and preferred metals from the rare earth elements are lanthanite metals such as oxides of lanthanum, cerium, praseodymium, and mixtures thereof. For example, cerium may be used in a mixture with one of the transition metal elements, such as a Ce/Zr mixed oxide. Obviously, other metal oxide oxidation catalysts may be used with the oxygen storage and donor type catalysts. Such other metal catalysts include noble metals and metals from groups IIA, IVA and mixtures thereof. Examples include palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide, and mixtures thereof.

The cerium catalyst precursor may be in the form of a cerium salt, such as cerium nitrate or other dispersible cerium forms, such as cerium sol made from cerium oxide hydrate or also known as cerium hydroxide, which is applied to the sorbent material in solution or sol form or as a coating to paper and then converted to cerium oxide to function as a catalyst at the high temperatures of the burning cigarette. Of course, the sol may be a low nitrate ceria hydrate sol. For the purposes of describing the present invention, the term catalyst is used to include any catalyst precursor.

A catalyst such as cerium oxide is used with the additive material. It has been found that the ability to control sidestream smoke is greatly diminished when the two materials are used separately or spaced apart from one another, with non-adjacent layers. Although in various arrangements of cerium, the ability to control certain sidestream smoke can be achieved. Preferably, the catalyst is substantially adjacent to the additive material. This can be achieved by blending the particulate catalyst with the additive material in a mixture, using an additive layer in contact with the catalyst layer, coating the catalyst on the surface of the additive, or impregnating the catalyst into an additive precursor or onto its porous surface, thereby resulting in the desired and unexpected sidestream smoke control performance. It should be understood that many other ingredients may be added to the mixture of the oxygen storage and donor metal oxide oxidation catalyst and the additive. Additional additives may be used to further increase sidestream smoke control or to modify other characteristics of the cigarette. Such additional additives may be mixed with the treatment agent or used elsewhere in the cigarette structure, although providing such additives must not negatively impact the ability of the treatment composition to treat sidestream smoke.

The composition may be formulated in a variety of ways to achieve co-mixing of the cerium with the sorbent material. For example, the sorbent material may be sprayed with cerium or impregnated with a cerium material in a solution of a cerium salt such as cerium nitrate or cerium oxide hydrate sol. Cerium oxide may be prepared as a fine separated powder, which is mixed with a fine powder of a sorbent material. It is particularly preferred that the catalyst powder have an average particle size of less than about 30 μm, more preferably less than 20 μm, most preferably from about 1.0 to 10 μm, and even more preferably from 6 to 10 μm to ensure complete mixing and blending of the materials.

As a general guide for selecting the particle size and surface area of the catalyst, one skilled in the art will recognize that the catalyst selected should have a surface area that will provide sites for catalyst activity for the migration of sidestream smoke components. This may result in catalyst particle sizes of greater than 30 μm in certain embodiments, provided that the catalyst particles are suitably distributed to effect the requisite degree of oxidation of sidestream smoke components.

It has now been surprisingly found that cerium oxide, particularly high surface area cerium oxide, is a relatively metal-poor oxide that functions as both an oxygen storage and donor catalyst and additive in accordance with the present invention. The porous cerium oxide particles can be produced to have a high surface area and an average particle diameter required as an additive. Cerium oxide is applied to the cigarette paper in a first amount as a catalyst and in a second amount as an additive in the treatment composition. Such amounts of cerium oxide generally correspond to the sum of the amounts for the catalyst and for the additive constructed according to another aspect of the present invention. In addition, high surface area ceria can be used with additives such as zeolites or other high surface area metals (e.g., zirconia or zirconium hydroxide).

Cerium can be formulated as a solution dispersion such as a cerium oxide sol or the like and applied to a sorbent material such as a zeolite. And then dried and burned to form a solid fixed on the surface of the sorbent material. When the cerium oxide particles are immobilized on the surface of an additive, such as a zeolite, the average particle size may be less than about 1.0 μm. The relative amount of cerium oxide immobilized on the zeolite can be from about 1% to 75% by weight based on the total equivalent amount of cerium oxide included with the zeolite. The preferred relative amount of cerium oxide immobilized on the zeolite can range from about 1% to 70% by weight based on the total equivalent amount of inclusion cerium oxide and zeolite.

A possible method for manufacturing a cerium oxide hybrid product immobilized on a zeolite is described in published application No. 60/318878, having application date 2001, 9 and 14, filed by the United states patent officeMaking metal oxide coated microporous materialsThe contents of which are incorporated herein by reference.

The process generally involves producing a catalytic ceria coated zeolite particle material having at least 1 wt.% of ceria coated on the outer surface of the zeolite particle, based on the total equivalent amount of the inclusion ceria and zeolite. In one aspect, the method generally comprises the steps of:

i) mixing an amount of a colloidal dispersion of cerium oxide hydrate sufficient to provide greater than 20% by weight cerium oxide when heated in step ii) with a compatible zeolite particulate material having an average pore diameter of less thanThereby leaving the colloidal dispersion at an outer surface location of the zeolite; and

ii) first heat treating the slurry at a temperature below about 200 ℃ and, second, fixing the resultant cerium oxide on the outer surface of the zeolite particulate material at a temperature above about 400 ℃ to form free-flowing bulk particles.

Certain combinations of treatment compositions can result in the appearance of ash that is considered unacceptable. Off-specification ash appearance characteristics include delamination, flaking, dirt, oily appearance and color. It has been taught that various ash modifiers can be added to paper to improve ash appearance. Such ash modifiers include metal oxides and/or carbonates such as zirconia, titania, magnesia, alumina, ceria, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate, and mixtures thereof.

It has now been found that treatment compositions can be required to be modified to improve ash characteristics. Such modification may include selection of the type of oxygen donor/storage catalyst and additives in particulate chemical or physical form. In particular, to modify the colour of the ash to make it more white or grey rather than dark charcoal, it has been found appropriate to reduce the amount of zeolite-based material as an additive. The amount of reduction in the zeolite-based material based on the dry weight of the paper is preferably less than 35 wt%, more preferably less than 25 wt%, most preferably less than 15 wt%. It is now clear that other types of fillers must be added to compensate for the reduced amount of zeolite-based additives. Suitable alternative metal oxides and/or carbonates include zirconia, titania, magnesia, alumina, ceria, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate, and mixtures thereof. A low/high surface area cerium/zirconium mixed oxide is preferred as the solid solution. Such additives may be prepared, for example, by co-precipitating a zirconium species and a cerium species, drying the precipitate, and then burning to form a crystalline solid solution product of high surface area ceria and zirconia. The ratio of ceria to zirconia in the crystal structure may be in the range of about 5: 95 to 95: 5. Further, this ratio may range from about 20: 80 to 80: 20, and the most preferred ratio may range from about 50: 50 to 80: 20. This material in its high surface area form also has catalytic properties and also provides oxygen storage and donor properties (where zirconia acts as an additive to ceria).

In terms of catalyst selection, it has also been found that the combination with cerium oxide contributes to a better ash appearance. For example, cerium oxide may be deposited on high surface area cerium oxide, cerium oxide hydrate deposited on high surface area cerium/zirconium oxide, and cerium oxide hydrate deposited and dried on high surface area cerium oxide particles. Also, the foregoing noble metal or transition metal type oxidation catalyst may be mixed with a cerium-based material such as palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide, and mixtures thereof.

Mixed metal oxide solid solutions are particularly preferred as oxygen donor catalysts due to the lighter ash color of the modified catalyst. The solid solution of mixed metal oxides includes an oxygen donor/storage oxidation catalyst and an additive. Preferred metal oxides as oxygen donor/storage materials in solid solution include lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, and mixtures thereof. Preferred metal oxides as additives include zirconia, alumina, magnesia, titania and mixtures thereof. Examples of such solid solutions include cerium/lanthanum mixed oxides, cerium/zirconium/lanthanum mixed oxides, cerium/zirconium/praseodymium mixed oxides, cerium/zirconium/lanthanum/praseodymium mixed oxides, cerium/zirconium/neodymium mixed oxides, and mixtures thereof. Solid solutions of these and other mixed oxides are readily available as commercial grade catalysts and are available from any of a number of catalyst suppliers. Other materials that may be substituted for solid solutions, such as cerium/zirconium mixed oxide solid solutions, include zirconia, alumina, magnesia, titania. Other solid solutions and mixed oxides contemplated for the present invention include cerium/aluminum mixed oxides, cerium/magnesium mixed oxides, cerium/titanium mixed oxides.

The oxidation catalyst, which may be included in solid solution, is usually present in trace amounts. Such catalysts include palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide, and mixtures thereof. They are typically included in solid solution at less than 1% by weight of the total solid solution. A preferred mixture and solid solution with traces of other oxidation catalysts is a mixture of the above catalyst with a cerium/zirconium mixed oxide solid solution. Preferably, the above-mentioned oxidation catalysts are included in solid solution either individually or as a mixture thereof. Nevertheless, in addition to this, the above-mentioned catalyst or a mixture thereof may also be applied to the surface of the cerium/zirconium mixed oxide solid solution particulate material.

The versatile solid solution of mixed oxides includes ceria/zirconia/magnesia/titania, wherein the ceria comprises between about 5% and about 75% of the solid solution.

It has also been found that the coating on the particle encapsulating paper is effective in improving ash characteristics. As previously mentioned, the treatment composition may be incorporated or coated onto an envelope paper, which is the bottom envelope paper of the tobacco rod. As noted above, one way to improve ash is to reduce the amount of sorptive additives such as zeolites and substitutes (and thus selected oxides). In addition, it has been found that, particularly with single wrap papers having a treatment composition added thereto, the calcium carbonate coating on the exterior of the wrap paper greatly improves the ash characteristics from an appearance standpoint. Quite surprisingly, the coating of particulate calcium carbonate serves to improve the ash characteristics thereof. Perhaps calcium carbonate chemically or physically binds the ingredients in the paper to produce a more uniform and mildly gray ash. The particulate calcium carbonate may be formulated as a slurry with a suitable binder as a coating on the encapsulating paper. Suitable binders include those typically used to coat calcium carbonate onto the encapsulating material, such as polyvinyl alcohol, starch, carboxymethyl cellulose (CMC), casein, soy protein, adhesive clays, and other suitable binders or gums. The particulate calcium carbonate has a particle size associated with its use as a filler in cigarette paper in manufacture. Therefore, the particle size is generally less than 10 μm and preferably about 3 μm. Nevertheless, certain grades of calcium carbonate having a particle size below 1 μm may also be used.

The surprising activity of the sidestream smoke treatment composition enables it to be used in cigarette papers of various porosities. It has also been found that the composition does not have to be applied to a wrapper having just a high porosity. The treatment composition works well in papers having a low porosity of about 0.5 to a very high porosity of about 1000 Ceresta units. Preferred porosities are typically below 200 Ceresta units, and most preferred porosities are typically about 15-60 Ceresta units. It is appreciated that paper is used as a two-layer or multi-layer encapsulation. The paper can be used as an outer wrap on a cigarette having a conventional cigarette paper. It is also noted that depending on the porosity, certain mixtures of catalyst and additive may be better used than others.

The composition can simply be sprayed onto one or both sides of the cigarette paper and absorbed into the paper. As shown in FIG. 1, the paper 10 is transported in the direction of arrow 12. The treatment composition 14 is sprayed as a slurry by the nozzle 16 onto the paper 10 to form a coating 18, and the coating 18 is dried onto the paper. In addition, the composition can be extruded as a film onto the surface of paper and used as single or multi-layer wrapping paper. As shown in fig. 2, the film coating apparatus 20 contains a treatment composition 14 in a slurry. The film mixer 20 lays a film 22 on the paper 10, and the paper 10 is conveyed in the direction of the arrow 12. The film is dried to form a coating 24 on the paper 10. With these arrangements, it is quite surprising that visible sidestream smoke from a burning cigarette actually disappears. The treatment composition may be applied to the exterior of the wrapper of a conventional cigarette.

The coating may be achieved by a roller applicator 26, as shown in FIG. 3. The treatment composition 14 is applied as a layer 28 on a roll 30. The doctor blade 32 determines the thickness of the ply 34, which is then fed onto the paper 10, which is transported in the direction of arrow 12. The layer is then dried to form a coating 36 on the paper 10.

Impregnation is achieved by using the roll coater 24 of fig. 4 and the resulting layer 36 is passed with the paper 10 in the direction of arrow 12 through rolls 38 and 40, the rolls 38 and 40 forcing the layer of material to the paper 10, thereby incorporating the impregnated components of the treatment composition into the paper.

Those skilled in the artIt will also be appreciated that various other coating methods, including transfer coating and the like, may be used to make the treated paper of the present invention. Mylar in spin coating^TMA sheet or other suitable continuous sheet can be used to transfer the coating composition from Mylar^TMThe sheet is transferred to the wrapper paper surface. This type of transfer coating is effective when the substrate sheet may not be readily accepted by the composition-coating roll due to the physical strength characteristics of the paper or similar material.

Alternatively, the treatment composition is added during the papermaking process. The composition may be introduced into the paper furnish as a slurry. Referring to fig. 5, the treatment composition in the furnish 42 is agitated by an agitator 44 to form a slurry in a holding tank 46. The slurry is transferred in a conventional papermaking manner and laid up in layers 48 on a moving conveyor belt 50 to form a finished cigarette paper 52. Thereby incorporating the treatment composition into the final paper product.

Yet another alternative is to sandwich the treatment composition between paper layers to form a double wrap wrapped on the tobacco rod. For example, the composition may be applied to the interior of the outer paper and/or the exterior of the inner paper, such as by the spraying process shown in fig. 1. Once the two papers are applied to the tobacco rod, the composition as a layer is sandwiched between the two papers. Each paper may be half the thickness of a conventional cigarette paper so that the double wrap does not significantly increase the diameter of the cigarette, thereby allowing the cigarette maker to be conveniently manufactured.

Referring to FIG. 6, the tobacco rod 54 has, for example, the cigarette paper 10 with the coating 18 on the outer surface of the paper being wrapped around the cigarette paper 10. Conversely, as shown in figure 7, the cigarette paper 10 may be applied with the coating 18 on the inner surface of the paper adjacent the tobacco rod 54.

Yet another alternative, as shown in figure 8, is to sandwich the coating 18 between the cigarette papers 56 and 58. The papers 56 and 58 and the intermediate dope 18 may be formed into a single cigarette wrapper that is applied to the tobacco rod 54. An alternative method is shown in figure 9 in which the tobacco rod 54 is enveloped by a conventional cigarette paper 60. On the conventional cigarette paper 60 is the cigarette paper 52 of figure 5 with the treatment composition therein. It is also contemplated that the paper 52 with the treatment composition incorporated therein is applied directly to the tobacco rod 54.

In yet another alternative of the invention, different combinations of sidestream smoke treatment paper may be provided in a double wrap construction, for example the coated paper of figure 7 may be used as the inner layer of paper and a different paper may be used to wrap the outer layer of paper with a double wrap (the double wrap may be conventional paper). The inner paper may also be paper having a treatment composition added thereto, such as the paper shown in fig. 9. The inner paper can be designed to provide sidestream smoke reduction by including all the necessary components of the composition such as the oxygen storage and donor metal oxide oxidation catalyst and non-combustible additives for the catalyst. Preferred examples of this type of combination include high surface area cerium/zirconium mixed oxides and zeolites and may optionally be enhanced with an oxidation catalyst such as platinum or palladium. In the double encapsulation system, the amount of zeolite may exceed 30% and a preferred range is, for example, 50% to 60% by weight.

The outer layer of the dual layer encapsulation may have different compositions and be designed to modify the ash to achieve the desired characteristics. For example, the outer paper can be designed to not only enhance ash appearance but also to improve the burn rate of the cigarette and minimize, if not eliminate, sparkle upon smoking of the cigarette. The outer layer may comprise, for example, a metal oxide such as a low surface area ceria, a ceria/zirconia solid solution, alumina, zirconia, titania, tin oxide, and the like. Alternatively, the cerium oxide hydrate may be coated on the metal oxide material of the outer layer to ensure the presence of sufficient oxygen to support combustion of the outer layer of the cigarette. The two layers, when combined into a double layer envelope, provide effective control of visible sidestream smoke. The adjacent papers burn uniformly to produce the desired ash, while the outer paper can serve to reduce or eliminate the uninterrupted sparkle caused by the highly reactive oxygen donor material.

A feature of the double wrap of the present invention is to provide significant flexibility to low sidestream smoke cigarette design. The individual sheets of the dual wrap design have the selected treatment composition impregnated, coated or contained in the individual sheets. The optional sheet having the treatment composition contained therein may also be coated with the same or different treatment composition to further increase sidestream smoke control and/or ash modification. To demonstrate such flexibility in designing low sidestream smoke cigarettes, exemplary treatment compositions for the inner and outer layers of paper are as follows:

outer paper

i) High surface area cerium/zirconium mixed oxide (75: 25) + low surface area zirconium oxide;

ii) high surface area alumina coated with cerium hydrate;

iii) low surface area alumina coated with cerium hydrate;

iv) high surface area zirconia coated with cerium hydrate;

v) high surface area cerium/zirconium mixed oxides (25: 75).

Inner layer paper

i) High surface area cerium/zirconium mixed oxide (75: 25) enhanced with palladium catalyst plus zeolite enhanced with palladium catalyst;

ii) a high surface area cerium/zirconium mixed oxide (75: 25) + zeolite reinforced with a palladium catalyst;

iii) a high surface area cerium/zirconium mixed oxide (75: 25) + zeolite, where the cerium/zirconium mixed oxide is enhanced with a palladium catalyst;

iv) high surface area cerium/zirconium mixed oxides (75: 25) + zeolites, where the cerium/zirconium mixed oxides are enhanced with platinum and tin catalysts;

these various compositions for the outer and inner layers may be mixed in various mixtures to provide sidestream smoke control and ash modification.

The preferred mixture for the outer paper is a solid solution of a high surface area cerium/zirconium mixed oxide (75: 25) and cerium oxide. The preferred composition for the inner paper is a high surface area cerium/zirconium mixed oxide (75: 25) enhanced with a palladium catalyst plus a solid solution of zeolite enhanced with a palladium catalyst. The outer paper has a coating formulation with 25% of a high surface area cerium/zirconium mixed oxide and 75% of a low surface area zirconium oxide on a dry weight basis. The inner paper has, on a dry weight basis, about 44% high surface area cerium/zirconium mixed oxide and 56% zeolite, both reinforced with palladium.

Those skilled in the art will appreciate that the above-described methods of providing a sidestream smoke treatment composition in or for use in a desired wrapper may be varied by varying the loading and the number of wrappers used on the tobacco rod. For example, two or more papers having different amounts of the composition on both sides of the paper can be used such that the loading on one side is reduced, thereby making application of the coating easier.

With any one such combination, it has now surprisingly been found that visible sidestream smoke has in fact been eliminated. At the same time, the cigarette paper exhibits conventional ash characteristics. It has been particularly surprising to find that simply applying the composition to the exterior of the wrapper reduces the visible sidestream smoke to a barely detectable level.

Various processing aids and mixtures thereof may be desirable to more easily specifically apply the treatment composition, depending on the manner in which the composition is used and applied to the cigarette. Such processing aids include laminating aids such as polyvinyl alcohol, starch, carboxymethylcellulose (CMC), casein or soy protein and other types of glues that may be used, various types of adhesive clays, inert fibrous materials such as zirconium fibers and zirconium/cerium fibers, such as those filed on 9/13/2001 and entitled "adhesive bonding agentZirconium/metal oxidation Biological fiberWhich is hereby incorporated by reference herein, is described in U.S. patent application No. 60/318614.

Penetrants may also be used to carry the composition into the paper. Suitable diluents such as water may also be used to dilute the composition so that it can be sprayed, curtain coated, air knife coated, rod coated, blade coated, stamp coated, dip coated, roll coated, slot die coated, transfer coated, and the like onto conventional cigarette paper.

The desired amount of treatment composition to be applied to the wrapper or to the wrapper, etc. is preferably about 2.5g/m²To about 125g/m². Most preferably about 2.5g/m²To about 100g/m². When expressed in weight percent, the paper may contain about 10 weight percent and preferably about 10% to 400 weight percent of the treatment composition. Although these loadings are in terms of cigarette paper, it will be apparent to those skilled in the art that these total loadings can be applied to two or more layers of paper.

The sidestream smoke reducing composition is typically applied as a water slurry side of the composition. The composition of the dry composition that can be slurried may vary depending on its application as a paper coating, potting or impregnation, etc. For example, the charged formulation may contain about 10% to 33% by weight of the cerium-based catalyst, 20% to 62% by weight of the additive, and 10% to 75% by weight of the ash modifier. Alternatively, the formulation may contain about 10% to 25% by weight of a cerium-based catalyst, 40% to 55% by weight of an additive, and 20% to 50% by weight of a non-additivated zeolite.

The slurry can be loaded into the furnish of a papermaking process or coated onto paper by various methods of coating or impregnated into paper by various impregnation methods. The particle size of the catalyst and additive of the slurry is in the range of about 1 μm to about 30 μm and most preferably about 1 μm to about 10 μm. The relative amount of catalyst mixed into the additive may be in the range of about 1% to 75% cerium, more preferably about 10% to 70%, and even more preferably about 20% to 70%, based on the weight of the total equivalent of catalyst and additive. Less than 1% of other catalysts, such as noble metal catalysts, may be fixed into the additive.

While the preferred embodiments of the present invention have been illustrated in detail, those skilled in the art will understand how to make various modifications without departing from the spirit of the invention or the scope of the appended claims.

Claims (38)

1. A low sidestream smoke cigarette comprising a conventional tobacco rod and a combustible treatment paper, wherein the combustible treatment paper has a sidestream smoke treatment composition, said treatment composition comprising an oxygen storage and donor metal oxide oxidation catalyst, a non-combustible particulate additive for said catalyst and a metal oxide and/or carbonate for modifying ash characteristics.

2. A low sidestream smoke cigarette comprising a conventional tobacco rod and a combustible treatment paper having a sidestream smoke treatment composition, said treatment composition comprising an oxygen storage and donor metal oxide oxidation catalyst, a non-combustible high surface area additive for the catalyst contained in said treatment paper, and a calcium carbonate coating on the outer surface of said treatment paper to improve ash characteristics.

3. A low sidestream smoke cigarette of claim 1 or 2, wherein said catalyst is selected from the group consisting of: a transition metal element oxide selected from oxides of group VB, VIB, VIIB, VIII and IB metals and mixtures thereof; rare earth metal oxides and mixtures thereof; and mixtures of the transition metal oxides and rare earth metal oxides.

4. A low sidestream smoke cigarette of claim 1 or 2, wherein said catalyst is a mixture of transition metal oxides and rare earth metal oxides, said transition metal oxides being selected from the group consisting of oxides of group IVB, VB, VIB, VIIB, VIII and IB metals and mixtures thereof.

5. A low sidestream smoke cigarette of claim 3, wherein said rare earth metal oxide is selected from the group consisting of oxides of scandium, yttrium, lanthanide metals and mixtures thereof.

6. A low sidestream smoke cigarette of claim 4, wherein said rare earth metal oxide is selected from the group consisting of oxides of scandium, yttrium, lanthanide metals and mixtures thereof.

7. A low sidestream smoke cigarette of claim 5 or 6, wherein said lanthanide metal oxide is selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide and mixtures thereof.

8. A low sidestream smoke cigarette of claim 1 or 2, wherein said adjunct is selected from the group consisting of clays, non-combustible milled fibres, monolithic mineral based materials, non-combustible carbon, zeolites and mixtures thereof.

9. A low sidestream smoke cigarette of claim 8, wherein said adjunct is a support for an oxidation catalyst selected from the group consisting of palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide and mixtures thereof.

10. A low sidestream smoke cigarette of claim 1 or 2, wherein said adjunct is a high surface area particulate.

11. A low sidestream smoke cigarette of claim 10, wherein said particulate adjunct is a zeolite based material in an amount of from 0.1% to 60% by weight based on total dry composition weight.

12. A low sidestream smoke cigarette of claim 1 or 2, wherein said adjunct is a support for a ceria sol applied thereto and dried.

13. A low sidestream smoke cigarette of claim 1 or 2, wherein said adjunct is a high surface area cerium oxide.

14. A low sidestream smoke cigarette of claim 1 or 2, wherein said adjunct is selected from the group consisting of zirconia, titania, magnesia, alumina, ceria, titania, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate and mixtures thereof, metal oxide fibres and milled porous ceramic fibres and mixtures thereof.

15. A low sidestream smoke cigarette of claim 1 or 2, wherein said oxygen storage and donor/metal oxide oxidation catalyst and additives therefor are a solid solution of mixed metal oxides.

16. A low sidestream smoke cigarette of claim 15, wherein said solid solution of mixed metal oxides further comprises an oxidation catalyst selected from the group consisting of palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide and mixtures thereof.

17. A low sidestream smoke cigarette of claim 15, wherein the adjunct is selected from the group consisting of zirconia, alumina, magnesia, titania and mixtures thereof.

18. A low sidestream smoke cigarette of claim 15, wherein said solid solution of mixed metal oxides is selected from the group consisting of cerium/lanthanum mixed oxides, cerium/zirconium mixed oxides, cerium/aluminum mixed oxides, cerium/magnesium mixed oxides, cerium/titanium mixed oxides, cerium/zirconium/lanthanum mixed oxides, cerium/zirconium/lanthanum mixed oxides, cerium/zirconium/praseodymium mixed oxides, cerium/zirconium/lanthanum/praseodymium mixed oxides, cerium/zirconium/neodymium mixed oxides and mixtures thereof.

19. A low sidestream smoke cigarette of claim 15, wherein said solid solution is a high surface area porous b particles.

20. A low sidestream smoke cigarette of claim 15, wherein said solid solution is a low surface area particulate.

21. A low sidestream smoke cigarette of claim 15, wherein said solid solution is a high surface area cerium/zirconium mixed oxide.

22. A low sidestream smoke cigarette of claim 21, wherein said cerium/zirconium mixed oxide is in a ratio of from 5: 95 to 95: 5.

23. A low sidestream smoke cigarette of claim 21, wherein an oxidation catalyst selected from the group consisting of palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide and mixtures thereof is either included in said solid solution of said cerium/zirconium mixed oxide or applied to the surface of said solid solution of cerium/zirconium mixed oxide.

24. A low sidestream smoke cigarette of claim 21, wherein said cerium/zirconium mixed oxide has a particle size greater than 1 μm.

25. A low sidestream smoke cigarette of claim 24, wherein said cerium/zirconium mixed oxide has a particle size of less than 30 μm.

26. A low sidestream smoke cigarette of claim 25, wherein said ratio is 75: 25 and said particle size is from 6 μm to 10 μm.

27. A low sidestream smoke cigarette of claim 1 or 2, wherein said treatment composition is 2.5g/m²To 125g/m²Is incorporated into the treated paper.

28. A low sidestream smoke cigarette of claim 1 or 2, wherein said treatment composition is coated on said treatment paper.

29. A low sidestream smoke cigarette of claim 1, wherein said ash modifying metal oxide and/or carbonate is selected from the group consisting of zirconium oxide, titanium oxide, magnesium oxide, aluminum oxide, cerium oxide, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate and mixtures thereof.

30. A low sidestream smoke cigarette of claim 29, wherein said ash modifying metal oxide and/or carbonate is zirconium oxide.

31. A low sidestream smoke cigarette of claim 1 or 2, wherein said oxygen storage and donor metal oxide oxidation catalyst is a porous particulate solid solution of cerium/zirconium mixed oxide.

32. A low sidestream smoke cigarette of claim 31, wherein said porous particulate solid solution of cerium/zirconium mixed oxide is a mixed oxide high surface area material.

33. A low sidestream smoke cigarette of claim 31, wherein zirconia and/or zeolite is used in admixture with said cerium/zirconium mixed oxide.

34. A low sidestream smoke cigarette of claim 33, wherein an oxidation catalyst is used with said cerium/zirconium metal oxide, zirconium oxide and/or zeolite.

35. A low sidestream smoke cigarette of claim 34, wherein said oxidation catalyst is selected from the group consisting of palladium, platinum, rhodium, tin oxide, copper oxide, iron oxide, manganese oxide and mixtures thereof, and the selected oxidation catalyst is either incorporated in said solid solution of the cerium/zirconium mixed oxide or applied to the surface of the particulate cerium/zirconium mixed oxide, zirconium oxide and/or zeolite.

36. A low sidestream smoke cigarette of claim 1, wherein said treatment composition is applied to the wrapper as a coating, said coating composition comprising a metal oxide or carbonate selected from the group consisting of zirconia, titania, magnesia, alumina, ceria, tin oxide, iron oxide, manganese oxide, calcium carbonate, zirconium carbonate, magnesium carbonate and mixtures thereof.

37. A low sidestream smoke cigarette of claim 1, wherein said combustible treatment paper comprises an inner and an outer paper sheet, said inner paper sheet comprising said treatment composition for reducing sidestream smoke, said outer paper sheet comprising a treatment composition for improving ash characteristics.

38. A low sidestream smoke cigarette of claim 1 or 2, wherein said catalyst is a precursor of said catalyst.