EA017412B1 - Filter including randomly-oriented fibers for reduction of particle breakthrough - Google Patents

Abstract

Provided is a cigarette filter (10) and method of making the filter. The filter (10) includes an adsorbent (12) dispersed within the filter (10) and a downstream plug (16) of randomly-oriented fibers (14). The randomly-oriented fibers (14) mechanically capture adsorbent particles entrained in tobacco smoke. One or more plugs (25) of axially-oriented fibers (30) may also be located upstream or downstream or both of the adsorbent (12), and are included in an amount sufficient to adjust the length of the filter (10).

Description

SUMMARY OF THE INVENTION

A filter assembly for a smoking article with reduced breakthrough of adsorbent particles is provided. The filter assembly contains an adsorbent including particles that can be captured by the smoke contained in the filter and a plug containing randomly oriented fibers. A plug containing randomly oriented fibers provides reduced breakthrough of adsorbent particles.

In a preferred embodiment, the filter assembly is a stub-gap-plug filter. Most preferably, a randomly oriented fiber plug is located downstream of the adsorbent. Preferably, the randomly oriented fiber plug is located directly downstream of the adsorbent.

In an embodiment, a plug of axially oriented fibers is located upstream of the adsorbent. In another embodiment, an axially oriented fiber plug is located downstream of the adsorbent.

In a preferred embodiment, the filter assembly comprises a plug of randomly oriented fibers from about 3 to about 10 mm long. One or more axially oriented fiber plugs may be added to adjust the length of the filter. However, in an embodiment, axially oriented fibers may not be included in the filter.

In a preferred embodiment, the filter assembly mechanically reduces the outflow of adsorbent particles.

A smoking article comprising a filter assembly that reduces or eliminates the breakthrough of adsorbent particles into the mainstream smoke is also provided.

In a preferred embodiment, the smoking article comprises a tobacco rod and a filter assembly. Preferably, the filter unit is a filter of the type plug-gap-plug, and the gap is filled with adsorbent. In one preferred embodiment, a randomly oriented fiber plug is located upstream of the gap (behind the cavity) filled with adsorbent. In one preferred embodiment, the tobacco rod comprises tobacco material and a wrapper. Preferably, the filter assembly is attached to one end of the tobacco rod with cigarette paper.

Also provided is a method of manufacturing a filter assembly for smoking articles, which reduces or eliminates the breakthrough of adsorbent particles in tobacco smoke.

In a preferred embodiment, the method includes filling the cavity of the filter assembly of the plug-gap-plug-gap type with an adsorbent, the cavity being limited to a plug of randomly oriented fibers and a plug of cellulose acetate. In another embodiment, the cellulose acetate plug is a plug of axially oriented fibers.

The proposed method of manufacturing a filter includes the arrangement of double plugs from axially oriented fibers with gaps between them; placing stubs containing randomly oriented fibers between the two stubs so as to form cavities at the front and rear ends of each second of the double stubs; placing an adsorbent containing particles that may be captured by smoke in said cavities; and cutting every second of these double plugs of axially oriented fibers with the formation of double filter nodes. The method may further include attaching a tobacco rod to each end of the double filter nodes and cutting the double filter nodes in the center to form finished cigarettes.

Brief Description of the Drawings

FIG. 1 - filter type plug-gap-plug for a smoking product of the prior art.

FIG. 2 is an embodiment of a plug-to-span-plug filter comprising a plug of randomly oriented fibers.

FIG. 3 is a second embodiment of a plug-to-span-plug filter, comprising a plug of randomly oriented fibers.

FIG. 4 is a third embodiment of a plug-to-span-plug filter, comprising a plug of randomly oriented fibers.

FIG. 5 shows a smoking article partially without a wrapper, comprising a plug-type filter, a plug-gap, comprising a plug of randomly oriented fibers.

The proposed filter is configured to be included in a smoking article, such as a filter cigarette. The filter contains filter material that contains randomly oriented fibers. Particles of adsorbent or fragments of particles of the adsorbent can be carried away by the mainstream smoke and escape through the mouthpiece end of the cigarette (i.e., particles may break through

- 1 017412 filter). Randomly oriented fibers mechanically trap such adsorbent particles, removing them from the mainstream smoke stream.

As used herein, the smoke-carried particles encompass microspheres, granules, dust, and finely divided fractions. powders and similar adsorbent particles. having a size of from about 0.1 to about 10 microns, which can be carried away by the mainstream smoke.

As used herein, the terms randomly oriented fibers, a randomly oriented fiber end cap, and randomly oriented fibers describe woven and non-woven fibers, including tangled continuous yarns oriented in different directions that are not substantially parallel to the direction of the mainstream smoke passing through the smoking article . In contrast, the axially oriented fibers in the filter plug are substantially parallel to the direction of the mainstream smoke and are formed into a continuous bundle, continuing in the axial direction with minimal entanglement. Randomly oriented fibers, randomly oriented fibers and randomly oriented stubs also describe non-woven materials that can be made using dry or wet spinning processes, including point bonding, spunbond production method, needle-punched material, non-woven material, suspension in water, etc. . A detailed description of the manufacturing methods for the manufacture of randomly oriented fiber tobacco rods can be found in US Pat. Nos. 3,111,702, 4,540,625 and 5,817,159, the disclosures of which are incorporated herein by reference.

Preferably, the filter is configured to be included in the filter cigarette. Cigarette filters are made in various designs. Typically, cigarette filters contain four main components: a filter tow, such as a bundle of cellulose acetate fibers or paper, which make up the bulk of the filter; a plasticizer (i.e., a softener added to bind the filter fibers together into a continuous filter rod); a cap wrapper (i.e., a paper wrapper that is used to hold the filter material) and adhesive used to attach the cap wrapper to a continuous filter rod.

Filter rods for manufacturing cigarette filters that can be attached to tobacco rods (e.g., cigarette paper) to produce filter cigarettes can be made by forming a bundle or bundle of filter material into a rod using a filter rod making device. Typically, the filter rod contains up to thirty thousand threads of filter material. The preferred filter material used to form the filter rod is cellulose acetate, which is a cellulose ester.

A plasticizer or a binder, such as triacetin, is added to the tow before being fed into the filter rod manufacturing apparatus. In addition, the tourniquet can be loosened and loosened, or flattened, usually by applying tension to the tourniquet and passing it over jets of air. A flattened tow may be passed through a funnel or other constricting device, and then through a hole of a certain shape to form a filter rod.

A plasticizer that can be added to the bundle during or after flattening can enhance the binding of the threads to each other at their intersection points when the bundle is connected. Thus, the addition of a plasticizer can increase the strength of the filter rod formed from the tow. The plasticizer may also have filtration properties. The properties of the finished filter rod (e.g., filtration efficiency, strength, dimensional stability, etc.) can be improved by curing (e.g., heating) the plasticizer.

For the manufacture of the filter can be used in various designs. Examples of filter structures include, but are not limited to, a single filter, a double filter, a triple filter, a cavity filter, a in-depth filter, a free flow filter, or combinations thereof. Single filters typically contain a cellulose acetate tow or cellulose paper materials. Single cellulose filters or paper filters can be effective tar and / or nicotine filters. Double filters typically contain a cellulose acetate mouthpiece end and a segment of pure cellulose or cellulose acetate. The length and pressure drop of the segments in the double filter can be adjusted to provide the desired filtration (i.e. adsorption and / or adsorption) and tightening resistance (CTO).

The filter may be attached to the tobacco rod to form a filter cigarette. In the manufacture of cigarettes, the cut filler composition can be combined with other cigarette additives and fed to a cigarette making machine to produce a tobacco column, which is then wrapped in tissue paper to form a tobacco rod that is cut into pieces and possibly glued to filter. The resulting cigarettes can be made with the desired characteristics using standard or modified methods and equipment for making cigarettes. Cigarettes can be in the length range from about 50 to about 120 mm. The circumference is usually from about 15 to about 30 mm, preferably about 25 mm. The packing density of the tobacco is usually in the range from about 100 to about 300 mg / cm ³ and

- 2 017412 preferably from about 150 to about 275 mg / cm ³ .

The cut tobacco filler is usually in the form of pieces or strips cut in width in the range of about 1/10 to about 1/20 inch or even about 1/40 inch (about 2.5 to about 1.3 mm, or even about 0, 6 mm). The length of the strips is in the range of about 0.25 to about 3 inches (between about 6.4 and about 76 mm). Cigarettes may additionally contain one or more flavorings or other additives (for example, flammable additives, combustion modifiers, colorants, binders, etc.).

Any suitable tobacco blend may be used as a filler. Examples of suitable types of tobacco materials include fire-dried tobacco, Burley, Bright, Maryland or Oriental tobaccos, rare or specialty tobaccos and mixtures thereof. The tobacco material may be provided in the form of tobacco leaf, processed tobacco materials, such as expanded or expanded tobacco, processed tobacco stems, such as cut-rolled or cut-expanded blooms, reconstituted tobacco materials or mixtures thereof. Tobacco may also contain tobacco substitutes.

The term mainstream smoke means a mixture of gases passing through a tobacco rod and exiting through the mouthpiece end of a filter, i.e. smoke coming out or drawn from the mouthpiece end of a cigarette while smoking a cigarette. The mainstream smoke contains smoke that is drawn through a burning area as well as through a paper wrapper of a cigarette. The term sidestream smoke refers to smoke generated during static combustion.

Carbon filters 105 of the stub-span-plug type of the prior art as shown in FIG. 1 comprise a layer 115 of adsorbent 112, such as activated carbon, between axially oriented fiber plugs 130. Typically axially oriented fibers are cellulose acetate fibers. Without being bound by theory, it is believed that when smoke is drawn in by a smoker through a filter, some particles carried away by smoke, dust, fine fractions or their combinations can penetrate the channels between individual fibers, migrate along the fibers, which leads to the breakthrough of adsorbent particles through the cigarette filter. In one preferred embodiment, a stub-gap-stub filter 105 is attached to the tobacco rod 160, which is wrapped with brown paper 170 to form a smoking article 100. Mouthpiece paper 165 surrounds the filter 105 and the portion of the tobacco rod 160.

The proposed filter assembly of a smoking article potentially reduces and / or prevents breakthrough of adsorbent particles by improving the mechanical trapping of smoke-entrained particles.

In one preferred embodiment, the filter assembly 10 is a stub-gap-plug filter assembly. Such a filter assembly 10 is shown in FIG. 2. Preferably, a portion of the adsorbent 12 containing smoke-entrained particles is located in the inner cavity 15 of the filter 10, and a plug 16 of randomly oriented fibers 14 is located to reduce the breakthrough of the adsorbent particles downstream of the mainstream smoke through the filter assembly 10. In theory, since the fibers 14 are not axially aligned, the adsorbent particles do not pass along the channels between the fibers or along the fibers, thereby reducing or preventing the adsorbent particles from breaking into the mainstream smoke.

The adsorbent and / or fumes carried by the smoke may be any absorbent material. Examples of adsorbents include molecular sieves, such as zeolites, silicas, silicates, aluminas, carbons (e.g., activated carbon), or combinations thereof. The preferred adsorbent is activated carbon. Preferably, the filter assembly contains from about 30 to about 200 mg of this adsorbent.

Activated carbon means any porous form of coal with a large surface area. Activated carbon can be obtained by heat treatment of any suitable carbon source. Activation treatment typically increases porosity, and activated carbon can be provided with a wide range of pore sizes, or the pore size can be controlled to provide the desired pore size distribution.

In a preferred embodiment, the coal is in the form of granules and the like. Preferably, the carbon in the preferred embodiment is activated carbon with a larger surface area, for example, coconut shell coal with a typical A8TM size (sieve mesh size) used in the cigarette industry or less . Particularly preferred activated carbon is offered by the companies P1CA I8A, 1ps., Tti1y og Sop5ss. | Ispess5. New Mexico. Activated carbon can also be made by carbonization of coal, wood, resin, peat, cellulose fibers, lignite and olive seeds. Carbonization is usually performed at elevated temperatures, for example, 400-1000 ° C in an atmosphere of inert gases, followed by activation (i.e. calcining calcination) under conditions of reduction or oxidation.

In a preferred embodiment, the activated carbon may be in the form of spherical particles. In other embodiments, activated carbon may be in the form of granules, fibers, or a combination thereof. Preferably, the activated carbon is made with the possibility of adsorption of the components of the main stream of smoke, in particular gas phases, including aldehydes, ketones and

- 3 017412 other volatile organic compounds, in particular 1,3-butadiene, acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, toluene, styrene, acetaldehyde and hydrogen cyanide.

In other embodiments, carbon may be in the form of coal on a tow, carbon paper, or a combination thereof.

Most preferably, activated carbon contains granular particles in the size range from about 100 microns to about 5 mm. In an embodiment, the activated carbon particles have an average size of from about 0.2 to about 2 mm (for example, about 200, 500, 1000, or 2000 microns).

The spherical particles of activated carbon contained in the filter assembly preferably have a size in the range of 0.20 to about 0.70 mm, as described in US Application 2003/0154 993, the contents of which are incorporated herein by reference in their entirety.

Preferably, the activated carbon has any desired pore size distribution that includes pores such as micropores, mesopores and macropores. The term microporous mainly refers to materials with a pore size of about 20 angstroms or less, while the term mesopores mainly refers to materials with a pore size of about 20-500 angstroms.

In an embodiment, activated carbon may be selected with an appropriate surface area for preferred adsorption or adsorption, or both for the target smoke components. For example, a preferred activated carbon typically has a surface area of greater than about 50 m ² / g (for example, at least about 100, 200, 500, 1000 or 2000 m ² / g). Typically, the absorbent capacity of activated carbon increases with increasing surface area. In addition, surface area usually increases with decreasing particle size. However, when used as a medium for cigarette filters, coal particles with a small pore size may be packed too tightly together to allow smoke to flow through the filter with the desired drag resistance (CTO) when smoking. On the other hand, if the particle size is too large, the surface area may not be sufficient to provide the required degree of filtration. Therefore, such factors can be taken into account when choosing coal particles suitable for filtering the main stream or sidestream smoke, or both at the same time.

Preferably, at least a part, if not all of the adsorbent, contains flavoring or is otherwise impregnated with flavoring, so that the adsorbent can not only remove one or more components of the smoke gas phase from the smoke, but also add flavor to the mainstream smoke stream. For example, a flavor may be added to activated carbon by applying a flavor to a batch of activated carbon in a tumbling drum (toggle switch) or, alternatively, in a bed of fluidized material with nitrogen as a fluidizing agent, and the flavor may then be sprayed onto carbon in that layer.

Preferably, the randomly oriented fibers are cellulose acetate fibers. In another embodiment, the randomly oriented fibers are polyester, polypropylene, and the like. In an embodiment, the randomly oriented fibers can be woven and / or non-woven when the fibers are randomly connected together.

In a preferred embodiment, the fibers are Υ-shaped. In another embodiment, the fibers may have a half-open shape or cross-section with an open cavity, for example, as the fibers described in US patent 6919105, US patent 6913784, and / or US patent 6907885, the contents of which are incorporated into this description by reference.

As shown in FIG. 2, the mouthpiece end 20 of the filter assembly 10 preferably comprises a plug 16 made of randomly oriented fibers 14. Preferably, the plug 16 is located downstream of the adsorbent 12 contained in the cavity 15 to prevent the movement of adsorbent particles from about 0.1 to about 10 μm in size through the channels between fibers and / or migration along the fibers, as in the filter nodes of the prior art using axially oriented fibers. In a preferred embodiment, the plug 25 of the axially oriented fibers 30 is located upstream of the adsorbent 12.

When smoking, the smoke is drawn first through the plug 25 of the axially oriented fibers 30, through the adsorbent 12 and further downstream through the plug 16 from the randomly oriented fibers 14. Due to the random orientation of the fibers of the plug 16 located further downstream, the adsorbent particles cannot pass through the channels between the fibers and / or migrate along the fibers, which leads to the mechanical capture of adsorbent particles carried away by the mainstream smoke.

In another embodiment shown in FIG. 3, the filter assembly 10 comprises a portion of the adsorbent 12 in the cavity 15. On each side of the portion of the adsorbent 12 lies a plug 16 of randomly oriented fibers 14.

In another embodiment, as shown in FIG. 4, the filter assembly 10 comprises a cavity 15 filled with adsorbent 12. Preferably, a cap 16 of randomly oriented fibers 14 is located directly behind a cavity 15 filled with adsorbent 12. Preferably, a cap 25 of axially oriented fibers 30 is located directly in front of the cavity 15. Also, another similar one is preferable. the plug 25 of the axially oriented fibers 30 is also located directly behind the plug 16 of the randomly oriented fibers 14.

- 4 017412

As shown in FIG. 5, the filter assembly 10 is configured to be included in the smoking article 50.

The term smoking article includes cigarettes, cigars, pipes and cigarillos. Unconventional cigarettes, such as cigarettes for electric smoking systems, as described in US Pat. No. 6,026,820 assigned to several patent holders; 5,988,176; 5915387 and 5499636 are also mainly included in the definition of smoking articles or cigarettes.

Preferably, the smoking article is a cigarette. The cigarette may contain tobacco material and a filter. In an embodiment, the cigarette may also contain at least one sorbent. A traditional cigarette usually contains two parts - a tobacco containing part, sometimes called a tobacco rod, and a filtering part - i.e. a filter that may be called a filtration zone. Mouthpiece paper typically surrounds a filter that forms the mouthpiece end of a cigarette.

Mouthpiece paper is applied to the tobacco rod to hold the filter and tobacco rod together. The tobacco core or tobacco-containing element of the cigarette comprises a paper wrapper in which tobacco is wrapped, and an adhesive holding the edges of the paper wrapper together. The tobacco rod has a first end that is permanently attached to the filter, and a second end that is ignited or heated for smoking tobacco. When the tobacco rod is ignited or heated for smoking, smoke passes from the ignited end upstream to the end of the tobacco rod filter and downstream through the filter.

The following is an example to illustrate filter embodiments, which however does not imply a limitation on the scope of the invention to these embodiments.

Example 1

A 6 mm cellulose acetate plug containing randomly oriented cellulose acetate fibers is located downstream of a cavity filled with 110 mg of activated carbon to create a filter.

Using filters made as in Example 1 and a control filter of the plug-gap-plug type made of two plugs of axially oriented cellulose acetate fibers, the possibility of breakthrough of activated carbon particles was measured under dry inhalation conditions without burning using a particle counter scattering light laser (Me1-Ope laser particle counter, model 237B: Iasi I11ga Lpa1u11S8, Richmond, CA).

When testing filters for a breakthrough of coal particles, a particle counter scattering laser light was placed near the cigarette holder, combined with the air flow through the cigarette.

The filter was inserted into the cigarette filter holder to a depth of approximately 9 ± 1 mm and under machine tightening in non-burning conditions (dry tightening) using 55 ml / tightening; tightening time 2 s; 12 puffs profile / cigarette .______________________________________________

Breakthrough particle number (particle size> 0.3 μm)

Average one hundred Filter one Filter 2 Filter 3 Filter 4 Filter 5 Filter 6 Filter 7 Filter 8 Test No. 1 251 522 351 167 47 22 31 86 fifty 38 Test 2 198 384 187 53 47 51 54 40 78 64 The control 1097 255 1010 1429 1155 1102 1087 738 1395 1395

The table shows the test results and a comparison of filters made in accordance with example 1 (tests No. 1 and 2) with traditional filters of the type plug-gap-plug with a cavity filled with activated carbon and a plug of axially oriented cellulose acetate fibers located further upstream and downstream relative to activated carbon (control).

Test No. 1 of filters made according to Example 1, containing randomly oriented cellulose acetate fibers, showed an average breakthrough of coal particles of about 251 particles per cigarette. The breakthrough of particles ranged from about 22 particles to about 351 particles per cigarette, which is a significant decrease relative to cigarette control filters.

Test No. 2 filters, performed according to example 1, showed an average breakthrough of coal particles of approximately 198 particles per cigarette. The breakthrough of particles ranged from about 40 particles to about 187 particles per cigarette, which is a significant reduction compared to control cigarette filters.

In contrast, a control filter, not containing randomly oriented cellulose acetate fibers, showed an average breakthrough of coal particles of about 1097 particles per cigarette. Thus, it is obvious that the use of randomly oriented cellulose acetate fibers in the filter significantly reduces the breakthrough of coal particles during smoking.

It is understood that the foregoing description are preferred embodiments.

- 5 017412 and therefore, is just an example of products and methods for their manufacture. It should be understood that changes and modifications of various embodiments in the light of the above knowledge are obvious to a person skilled in this field. Accordingly, alternative embodiments may be practiced without departing from the spirit and scope of the appended claims.

Claims (9)

1. A filter assembly (10) for a smoking article, comprising an adsorbent (12), including adsorbent particles that can be trapped in smoke; a plug (16) located downstream of the adsorbent (12) and containing randomly oriented fibers (14) in such a way that a reduced breakthrough of the adsorbent particles is provided. 2. The filter assembly (10) according to claim 1, in which the plug (16) containing randomly oriented fibers has a length of from about 3 to about 10 mm. 3. The filter assembly (10) according to claim 1 or 2, wherein the plug (16) of randomly oriented fibers (14) contains one or more kinds of fibers selected from randomly oriented fibers of cellulose acetate, polyester and polypropylene. 4. The filter assembly (10) according to any preceding claim, wherein the adsorbent (12) comprises one or more of charcoal on a tow, carbon paper, spherical coal, granular coal, coal particles, and the like. in the cavity. 5. The filter unit (10) according to any preceding paragraph, which is a filter of the type plug-gap-plug in which the adsorbent (12) contains spherical coal located in the gap, and the plug (16) of randomly oriented fibers (12) contains randomly oriented cellulose acetate fibers included in the filter type stub gap-stub downstream. 6. The filter assembly (10) according to any preceding paragraph, comprising at least one plug (25) of axially oriented fibers (30) located at least in front of and behind the adsorbent (12), said at least one plug (25) of axially oriented fibers inserted into one or more filter segments included in the filter assembly in an amount sufficient to adjust the length of the filter assembly. 7. The filter assembly (10) according to any preceding claim, wherein the adsorbent (12) is selected from the group consisting of a molecular sieve, coal, and a combination thereof. 8. A cigarette comprising a filter assembly attached to a tobacco rod according to any preceding claim, wherein the outer surface of the plug containing randomly oriented fibers is in contact with cigarette paper attaching the filter assembly to the tobacco rod. 9. A method of manufacturing a filter, including the arrangement of double plugs from axially oriented fibers with gaps between them; placing plugs containing randomly oriented fibers between the double plugs so as to form cavities at the front and rear ends of each second of the double plugs; placing an adsorbent containing particles that can be captured by smoke into said cavities and cutting every second of said double plugs from axially oriented fibers to form double filter assemblies.