CN112998312A

CN112998312A - Tobacco smoke filter

Info

Publication number: CN112998312A
Application number: CN202110183396.8A
Authority: CN
Inventors: 艾哈迈德·法希胡尔·利桑; 保罗·罗纳德·莫里斯
Original assignee: Essentra Filter Products Development Co Pte Ltd
Current assignee: Essentra Filter Products Development Co Pte Ltd
Priority date: 2015-08-03
Filing date: 2015-08-03
Publication date: 2021-06-22
Anticipated expiration: 2035-08-03
Also published as: CN106387993B; CN106387993A; CN112998312B; WO2017021422A1

Abstract

A method of producing a (e.g. fluted) tobacco smoke filter or filter element comprising the steps of: longitudinally advancing a continuous stream of dual filter rods, wherein the dual filter rods in the longitudinally advancing stream are longitudinally spaced apart from one another, each dual filter rod comprising a longitudinally extending core of tobacco smoke filtering material, and wherein each dual filter rod comprises a first base rod at a first end of the dual filter rod, a second base rod at a second end of the dual filter rod, and a third base rod positioned longitudinally between the first and second base rods; providing a common wrap around a continuous stream of dual filter rods to provide a product rod comprising a plurality of wrapped dual filter rods spaced longitudinally from one another within the product rod; severing the product rod at a position half way along the third base rod; and/or cutting the product rod at a position halfway the space between the dual filter rods.

Description

Tobacco smoke filter

The present application is a divisional application of an application having an application date of 2015, 8/3, application number of 201510479274.8 and a name of "tobacco smoke filter".

Technical Field

The present invention relates to tobacco smoke filters and filter elements for tobacco products such as cigarettes.

Background

There has been increasing commercial interest in recent years in the use of "shaped filters", i.e. tobacco smoke filters comprising one or more elements which extend longitudinally with respect to (e.g. extend longitudinally through; extend longitudinally along) a core of tobacco smoke filtering material, such elements being visible at the mouth end of the filter as threads or extruded elements. One advantage of shaped filters over standard tobacco smoke filters is that they provide a unique mouth end appearance, which is useful for branding and anti-counterfeiting purposes.

However, there is a problem in that only elements having a symmetrical cross-section can be incorporated in a shaped filter using existing manufacturing methods. This is because tobacco smoke filters are typically manufactured by a process comprising the steps of:

providing a multiple filter rod (e.g., a dual filter rod) comprising two longitudinally extending cores of filter material placed end-to-end in mirror image relationship;

attaching a cigarette to each end of the filter rod; and

the dual filter rod is cut at half its length to provide two separate cigarettes.

This method can be used with a dual filter rod comprising an element visible at the mouth end of the filter. However, if the cross-sectional shape of the elements is asymmetric, the shapes of the elements at the mouth ends of two filters produced by this method will be mirror images of each other. This is clearly unsatisfactory for branding and anti-counterfeiting purposes, as one filter will have the correct image (e.g. logo) and the other filter will have the incorrect image (mirror image).

It is therefore desirable to provide a method of manufacturing filters/filter elements in which the mouth end appearance of all the filters/filter elements formed by the method is the same, even where the elements extending longitudinally of the filter rod have an asymmetric cross-section (the term "asymmetric" herein, as in for example an asymmetric cross-section, meaning a trans-symmetric).

The present application provides a new method of making a fluted tobacco smoke filter or filter element that meets this need, and provides a filter/filter element that has the same, rather than a mirrored, end appearance regardless of the cross-section of the extruded element. Thus, a larger variety of element cross-sectional shapes can be used in the method than in methods previously known in the art, making the method particularly useful for branding and anti-counterfeiting purposes.

Recess filters are well known in the tobacco industry. It is typically manufactured by wrapping a continuous stream of filter segments at spaced intervals in a relatively stiff plug wrap. Recess filters are obtained by cutting the filter flow in regions where no filter elements are present-the stiff plug wrap provides sufficient rigidity to enable the manufacture and use of tobacco products without crushing the exposed paper end of the filter. Recess filters provide additional distinctions in end appearance as well as filter performance.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a method of manufacturing (e.g. fluted) tobacco smoke filters or filter elements;

the method comprises the following steps:

longitudinally advancing a continuous stream of dual filter rods, wherein the dual filter rods in the longitudinally advancing stream are longitudinally spaced apart from one another, each dual filter rod comprising a longitudinally extending core of tobacco smoke filtering material, and wherein each dual filter rod comprises a first base rod at a first end of the dual filter rod, a second base rod at a second end of the dual filter rod, and a third base rod positioned longitudinally between the first and second base rods; providing a common wrapper around the continuous stream of dual filter rods to provide a product rod comprising a plurality of wrapped dual filter rods spaced longitudinally from one another within the product rod; cutting off the product rod at a position aligned with a half of the third base rod; and/or cutting the product rod in a position aligned at one half of the space between the dual filter rods.

It will be appreciated that by cutting the product rod in register with a position half of each third base rod and cutting the product rod in register with a position half of each space between the dual filter rods, the product rod will be cut into individual recess filter/filter components for subsequent use. Alternatively, a dual filter product rod is obtained by first cutting the product rod in alignment with a position half way up the third base rod and cutting the product rod in alignment with a position half way up the next third base rod in the stream, which is the next dual filter rod (see fig. 5 a). The dual filter product rod may then be cut off aligned at a position half way along its length to provide two recess filter/filter elements for subsequent use. Typically the dual filter product rod will be attached to the tobacco housing (e.g. by ring tipping) at each end before final cutting (aligning the position at half the length of the dual filter product rod to which the tobacco housing has been attached) to provide two groove filter cigarettes. It will be appreciated that these methods are within the aspects of the invention defined above.

The first base rod preferably comprises a first longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; and a dual filter rod first element extending longitudinally with respect to (the first) core of tobacco smoke filtering material (e.g. extending longitudinally through the core of tobacco smoke filtering material; extending longitudinally along the core of tobacco smoke filtering material), the first element being visible at a first end of the dual filter rod. The second base rod preferably comprises a second longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; and a dual filter rod second element extending longitudinally with respect to the (second) core of tobacco smoke filtering material (e.g. extending longitudinally through the core of tobacco smoke filtering material; extending longitudinally along the core of tobacco smoke filtering material), the second element being visible at the second end of the dual filter rod. The cross-section of the first element (extending longitudinally with respect to the first core of tobacco smoke filtering material) as seen at the first end of the dual filter rod is preferably a mirror image of the cross-section of the second element (extending longitudinally with respect to the first core of tobacco smoke filtering material) as seen at the second end of the dual filter rod. The third base rod preferably comprises a third longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material. The third basebar is preferably a basebar as is well known in the art (e.g., a monoacetate basebar without wraps). The cross-sections of the first (longitudinally extending) element and the second (longitudinally extending) element are preferably asymmetric.

The dual filter rod may include one or more additional base rods (i.e., a fourth base rod, a fifth base rod, a sixth base rod, or more) positioned longitudinally between the first base rod and the second base rod.

It will be appreciated that the present method produces two tobacco smoke filter/filter elements having the same mouthpiece appearance, even where the longitudinally extending elements have an asymmetric cross-section. As best shown in fig. 5a, 7 and 8, the present method can provide a dual filter product rod. In a subsequent filter cigarette production process, the dual filter product rod may be attached to the tobacco housing at each end (e.g. by ring tipping) prior to final cutting (aligning the position at half the length of the dual filter product rod to which the tobacco housing has been attached) to provide two recess filter cigarettes. As can be observed in figure 5a, the asymmetric cross-sections of the two elements in the dual filter product rod are mirror images of each other, so that when the final cut for providing two recess filter cigarettes is made, the cigarettes are oriented in the same direction (by turning one cigarette in the plane in which the cut is made), the asymmetric cross-sections that can be seen at the ends of the cigarettes are the same.

The first (longitudinally extending) element visible at the first end of the dual filter rod is preferably a pressing element and/or the second (longitudinally extending) element visible at the second end of the dual filter rod is preferably a pressing element.

The dual filter rods in continuous flow are preferably aligned such that the longitudinal axis of their cylindrical cores is oriented along the longitudinal direction of the flow. The dual filter rods in the longitudinally advancing flow are preferably longitudinally spaced from each other (i.e., each dual filter rod is longitudinally spaced from the next dual filter rod along the continuous flow).

The tobacco smoke filtering material (used in aspects of the invention) may be, for example, any of those materials commonly used in tobacco smoke filter products (typically filamentary, fibrous, mesh or extruded materials). The filter material may be a natural or synthetic, for example, cotton or plastic, such as polyethylene or polypropylene, filamentary tow, or cellulose acetate filamentary tow. The filter material may be, for example, natural or synthetic staple fibers, raw cotton, web materials such as paper (typically pleated filter paper) and synthetic nonwovens, and extruded materials (e.g., starch, synthetic foam). It will be appreciated that the tobacco smoke filtering material used for each of the first, second and third (and fourth) base rods may be the same as or different from the filtering material used in any other base rod.

The longitudinally extending (e.g. extruded) element(s) for the filter rod may comprise a thermoplastic polymer, for example cellulose acetate, polyethylene, polypropylene, polylactic acid, polyester or mixtures thereof. Preferably, the element extending longitudinally with respect to the filter rod comprises cellulose acetate. Processes for preparing cellulose acetate powders are known (see for example US 4228246). Cellulose ester particles are commercially available from Rotuba Extruder, Linden, N.J., under the trademark "Naturacell". The cellulose ester particles can be converted into elements. The longitudinally extending elements (e.g. comprising extruded thermoplastic polymers such as extruded cellulose acetate) in respect of the filter rod may also comprise a plasticiser (such as triacetin). The amount of plasticizer in the element may be from 7% to 42% by weight of the element, for example from 15.1% to 35% by weight of the element. It should be understood that the elements for each of the first and second base rods may be the same as or different from the elements used in the other base rod.

The first, second and third base bars according to the present invention may be made as continuous bars, as is well known in the art. The continuous rod is cut into finite lengths for subsequent use (i.e., composition to form a dual filter rod) as it continuously issues from the production machine outlet. The cut may be cut into base rods as defined and described above, or first cut into double or higher (typically four or six times) lengths for subsequent use. The first base rod, the second base rod and the third base rod may be combined to form a dual filter rod by methods known in the art.

According to a further aspect of the present invention, there is provided a dual filter rod comprising a first base rod at a first end of the dual filter rod, a second base rod at a second end of the dual filter rod, and a third base rod positioned longitudinally between the first and second base rods (and abutting each of the first and second base rods);

wherein the first base rod comprises a first longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; and a first element extending longitudinally with respect to (e.g. extending longitudinally through; extending longitudinally along) the first core, wherein the first element is visible at the first end of the dual filter rod; and is

Wherein the second base rod comprises a second longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; and a second longitudinally extending element extending longitudinally with respect to (e.g. extending longitudinally through; extending longitudinally along) the second core, wherein the second element is visible at the second end of the dual filter rod; and is

Wherein the cross-section of the first element visible at the first end of the duplex filter rod is a mirror image of the cross-section of the second element visible at the second end of the duplex filter rod.

Preferably, the dual filter rod further comprises a wrap (engaged around the base rod), wherein a first end of the wrap extends beyond the first end of the dual filter rod to define a first (e.g. tubular) cavity (or groove) at the first end of the dual filter rod, and a second end of the wrap extends beyond the second end of the dual filter rod to define a second (e.g. tubular) cavity (or groove) at the second end of the dual filter rod. Preferably, the cross-section of the first and second elements is asymmetric.

The dual filter rod may include one or more additional base rods (i.e., a fourth base rod, a fifth base rod, a sixth base rod, or more base rods) positioned longitudinally between the first base rod and the second base rod.

According to a further aspect of the present invention, there is provided a dual filter product rod comprising:

a first base rod comprising a first longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material, and a first element extending longitudinally with respect to (e.g. extending longitudinally through; extending longitudinally along) the first core of tobacco smoke filtering material;

a second base rod comprising a second longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material, and a second element extending longitudinally with respect to (e.g. extending longitudinally through; extending longitudinally along) the second core of tobacco smoke filtering material;

a third base rod comprising a third longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; the third base rod abuts against the first base rod at one end;

a fourth base rod comprising a fourth longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; the fourth base rod abuts against the second base rod at one end; and

a wrap; wherein

An end portion of the first base rod not abutting the third base rod (that is, an end portion of the first base rod opposite to the third base rod) is longitudinally spaced apart from an end portion of the second base rod not abutting the fourth base rod (that is, an end portion of the second base rod opposite to the fourth base rod); and the wrap is engaged around (and encircles) the third, first, second and fourth base bars so as to define a wrapped central cavity between the first and second base bars.

Preferably, the cross-section of the first and second elements is asymmetric.

Preferably, the (e.g. asymmetric) cross-section of the first element (e.g. at the end of the first base rod not abutting the third base rod) is a mirror image of the (e.g. asymmetric) cross-section of the second element (e.g. at the end of the second base rod not abutting the fourth base rod).

It will be appreciated that a dual filter product rod according to this aspect of the invention may be attached to the tobacco housing at each end (for example by ring end tipping) and then cut aligned to a position at half of the central cavity to provide a two fluted filter cigarette. The recess or cavity is formed (defined) by that part of the wrap which overhangs the end of the first/second base bar after the wrapper has been cut.

The dual filter product rod may include one or more additional base rods. In a preferred embodiment, one (or more) additional base rods are positioned between the first and third base rods and one (or more) additional base rods are positioned between the second and fourth base rods.

In another preferred embodiment, one (or more) additional base rods abut to the end of the third base rod not abutting the first base rod; and one (or more) additional base rods abut to the end of the fourth base rod not abutting the second base rod.

According to a further aspect of the invention, there is provided a product rod comprising a plurality (e.g. two, four, six, etc.) of dual filter rods longitudinally spaced from one another, wherein each dual filter rod comprises a longitudinally extending core of tobacco smoke filtering material, and wherein each dual filter rod comprises a first base rod at a first end of the dual filter rod, a second base rod at a second end of the dual filter rod, a third base rod located longitudinally between the first and second base rods; wherein the common wrap is engaged around (and encircles) the plurality of dual filter rods such that adjacent dual filter rods define a wrapped cavity therebetween. It will be appreciated that the common wrap rod defines a wrapped cavity between each pair of adjacent dual filter rods.

According to a further aspect of the invention, there is provided a filter or filter element comprising a longitudinally extending (e.g. substantially cylindrical) core of tobacco smoke filtering material; and an element extending longitudinally with respect to the core (e.g. extending longitudinally through the core of tobacco smoke filtering material; extending longitudinally along the core of tobacco smoke filtering material), wherein the element is visible at least at a first end of the filter or filter element, and wherein the element has an asymmetric cross-section.

Preferably, the filter or filter element further comprises a wrap (engaged around the core), wherein a first end of the wrap extends beyond a first end of the longitudinally extending core of filter material about which the wrap is engaged to define a (e.g. tubular) cavity or "groove" at the first end of that core of filter material. The second end of the wrap may be substantially flush with the second end of the longitudinally extending core of filter material about which the wrap is joined. Preferably, the (longitudinally extending) element is a press element. The longitudinally extending core of tobacco smoke filtering material may comprise a first core of tobacco smoke filtering material (e.g. located at a first end of the filter element), the first core comprising an element extending longitudinally with respect to the core, the element being visible at the first end of the filter element; and a second core of tobacco smoke filtering material (which may not include elements extending longitudinally with respect to the core). The second core may be located at an end of the first core opposite the end at which the first end of the filter element is visible.

The tobacco smoke filtering material (used in filters, filter elements, dual filter product rods, etc. according to aspects of the invention) may be any of those materials (typically filamentary, fibrous, mesh or extruded) such as are commonly used in tobacco smoke filter products. The filter material may be a natural or synthetic, for example, cotton or plastic, such as polyethylene or polypropylene, filamentary tow, or cellulose acetate filamentary tow. The filter material may be, for example, natural or synthetic staple fibers, raw cotton, web materials such as paper (typically pleated filter paper) and synthetic nonwovens, and extruded materials (e.g., starch, synthetic foam).

The longitudinally extending (e.g., extruded) elements with respect to the core/filter rod may comprise a thermoplastic polymer, such as cellulose acetate, polyethylene, polypropylene, polylactic acid, polyester, or mixtures thereof. Preferably, the element extending longitudinally with respect to the core/filter rod comprises cellulose acetate. Processes for preparing cellulose acetate powders are known (see for example US 4228246). Cellulose ester particles are commercially available from Rotuba Extruder, N.J., under the trademark "Naturacell". The cellulose ester particles can be converted into elements. The longitudinally extending elements (e.g., comprising extruded thermoplastic polymers such as extruded cellulose acetate) with respect to the core/filter rod may also comprise a plasticizer (such as triacetin). The amount of plasticizer in the element can be from 7% to 42% by weight of the element, for example from 15.1% to 35% by weight of the element.

According to a further aspect of the present invention, there is provided a method of manufacturing a dual filter rod, or a dual filter product rod, or a product rod comprising a plurality (e.g. two, four, six, etc.) of dual filter rods, or a product comprising a plurality (e.g. two, four, six, etc.) of dual filter product rods;

the method comprises the following steps:

longitudinally advancing a continuous stream of dual filter rods, wherein the dual filter rods in the longitudinally advancing stream are longitudinally spaced apart from one another, each dual filter rod comprising a longitudinally extending core of tobacco smoke filtering material, and wherein each dual filter rod comprises: a first base rod located at a first end of the dual filter rod; a second base rod located at a second end of the dual filter rod; and a third base rod positioned longitudinally between the first and second base rods; providing a common wrap around the continuous stream of dual filter rods to provide a product rod comprising a plurality of wrapped dual filter rods spaced longitudinally from one another within the product rod; cutting off the product rod at a position aligned with a half of the third base rod; and/or cutting the product rod in a position aligned at one half of the space between the dual filter rods.

A dual filter product rod is obtained by cutting the product rod in alignment with a position half way up the third base rod and in alignment with a position half way up the next third base rod in the stream, which is located in the next dual filter rod (see figure 5 a). The dual filter product rod may then be cut at a position aligned at half the length of the dual filter product rod to provide two recess filter/filter elements for subsequent use. Typically, the dual filter product rod will be attached to the tobacco housing at each end (e.g. by ring tipping) before final cutting (aligning the position at half the length of the dual filter product rod to which the tobacco housing has been attached) to provide a cigarette with two fluted filters. It should be understood that these methods are within the above-defined aspects of the invention.

The third (and fourth, if present) base rod according to the invention may be, for example, a Combined Performance Filter (CPF) base rod (for example, a base rod such as disclosed in GB 2133269). CPF-based rods are characterized by an inner liner with embossed grooves over a portion of its length and have the advantage of providing increased filtration efficiency and/or lower pressure drop compared to standard cellulose acetate filters. In a less preferred embodiment, the first and second base rods may be CPF base rods to provide a unique end appearance.

The first and second base bars preferably have a length of from 5mm to 20mm, for example from 7.5mm to 15 mm. The third and fourth base bars according to the invention preferably have a length of from 5 to 40mm, for example from 10 to 20 mm.

The tobacco smoke filter of the present invention may have a length of from 15mm to 80mm, for example from 17mm to 35mm, for example from 20mm to 30 mm. The groove portion of the filter end (i.e. the length of the end of the wrapper to define the cavity at the end of the filter (e.g. mouth end) extending beyond the end of the core where the wrapper engages) may have a length of 3mm to 10mm, and most preferably 4mm to 6 mm. The longitudinally extending core of tobacco smoke filtering material may have a length of 10mm to 80mm, for example 14mm to 27mm, for example 17mm to 25 mm. The tobacco smoke filter may have a circumference of 14mm to 28mm, for example 16mm to 26mm, for example 16mm to 17mm or 24mm to 25 mm. The final filter cigarette may be ventilated or unventilated and have any circumference range conventionally used in smoking products (e.g., circumferences of c.14mm to c.28mm).

Any dual rod, dual filter product rod, filter or filter element according to the present invention may include additives (e.g., activated carbon) and/or flavorants (e.g., menthol, peppermint oil). The flavoring agent may be contained in one or more containers (e.g., one or more capsules, such as one or more breakable capsules). The additive and/or flavourant may be included in the first base rod and/or the second base rod and/or the third base rod, for example in an element of the first base rod or the second base rod that extends longitudinally with respect to the core of tobacco smoke filtering material, or in the tobacco smoke filtering material itself. The additives and/or flavourants may be added by techniques known in the cigarette filter manufacturing industry, for example by directional spraying. In another example, the tobacco smoke filter may comprise (e.g. in the first, second or third base rod) a breakable capsule containing a flavouring agent. The additives and/or flavorants may alter or enhance the smoking experience. However, in other examples, the filter or filter element does not include a flavorant or a flavoring agent.

The wrap may be paper, for example plug wrap, for example hard plug wrap. The wrap may be a porous wrap or a non-porous wrap. The wrap may be a porous wrap up to 32k Cu or a non-porous wrap. The wrap may be paper having a basis weight of from about 40 grams per square meter to about 120 grams per square meter. For example, for recess filters having a standard (c.24mm to c.25mm) circumference, the wrap may have a basis weight of from about 80 grams per square meter to about 120 grams per square meter, for example a basis weight of about 100 grams per square meter. For fine or ultra-fine recess filters (e.g. down to a circumference of about 16mm to 17mm), the wrap may be plugwrap having a lower basis weight, e.g. about 50 grams per square meter.

Cigarettes comprising filters or filter elements as described herein are also envisaged to be within the scope of the invention.

In the filter cigarette according to the invention, the filter of the invention (or a filter comprising the filter element of the invention) (or a filter manufactured by the method according to the invention, or a filter comprising the filter element manufactured by the method according to the invention) is connected to the wrapped tobacco rod with one end of the filter towards the tobacco leaf. The filter may be attached to the wrapped tobacco rod, for example by ring tipping (which engages around only the adjacent ends of the (wrapped) filter and rod, leaving most of the filter wrap exposed) or more preferably by a full tipped overwrap (which engages around the full filter length and the adjacent end of the tobacco rod). The cigarette may include a tipping overwrap (e.g. a tipping paper) along with the outer wrap of the filter to provide a desired (e.g. further increased) stiffness to the final fluted filter cigarette.

Any filter or filter cigarette according to the invention may be unventilated or may be ventilated by methods known in the art, for example by laser perforation using a pre-perforated or air permeable wrap (plug wrap), and/or wrap (plug wrap) and laser perforation of the tipping overwrap. Ventilation of a fully tipping overwrap may likewise be breathable in nature or provided with ventilation holes, and in ventilated products where both tipping wrappers and tipping overwraps are present, ventilation through the overwrap is generally aligned with ventilation through the tipping wrapper. Ventilation holes through the tipping wrapper, through the tipping overwrap, or through both, may be made by laser perforation during filter production or during filter cigarette production.

According to a further aspect of the present invention there is provided a multi-rod comprising a plurality (e.g. two, four, six, etc.) of dual filter rods connected end-to-end in mirror image relationship as described above and/or herein.

Drawings

The invention will now be described with reference to the following examples and the accompanying drawings, in which:

FIG. 1 is a perspective view of a cut-away portion of a first base rod according to one aspect of the present invention;

FIG. 2 is a perspective view of a cut-away portion of a second base rod according to an aspect of the present invention;

FIG. 3 is a perspective view of a cut-away portion of a third base rod according to an aspect of the present invention;

FIG. 4 is a perspective view of a cut-away portion of a dual filter rod according to an aspect of the present invention;

FIG. 5 is a perspective view of a cut-away portion of a dual filter rod according to an aspect of the present invention;

FIG. 5a is a perspective view of a cut-away portion of a dual filter rod according to an aspect of the present invention;

figure 6 is a perspective view of a cut-away portion of a tobacco smoke filter according to an aspect of the present invention;

FIG. 7 is a perspective view of a cut-away portion of a product rod in the form of a continuous stream of dual filter rods in accordance with an aspect of the present invention;

figure 8 shows an apparatus for manufacturing the dual filter rod shown in figures 4 and 5 and the tobacco smoke filter of figure 6 according to an example of the method of the present invention.

Detailed Description

Fig. 1 is a perspective view of a cut-away portion of a first base rod 1 a. The first base rod 1a comprises a longitudinally extending generally cylindrical core 2a of tobacco smoke filtering material. The generally cylindrical core 2a is in the form of a cylindrical cellulose acetate plug having a length of 10mm and a circumference of about 25 mm. The generally cylindrical core 2a is made of cellulose acetate tow which has been gathered and compressed into the form of a rod by methods well known in the art. The first base rod 1a further comprises a first continuous extruded element 3a formed of extruded cellulose acetate, which first continuous extruded element 3a extends longitudinally through the substantially cylindrical core 2a, such that one end of the element 3a can be seen at the first end 4a of the base rod. The element 3a of continuous extruded cellulose acetate has an e-shaped cross-section and extends through the body of the rod 1a from one end to the other so that there is an e-shaped logo which can be seen at the first end 4a of the base rod. It will be appreciated that the e-shape is reversed at the other end of the base rod. The first base rod 1a may be manufactured by the method disclosed in WO 2011/058319. Methods for making extruded grade cellulose acetate powders are known (see, for example, US 4228246). Extruded grade cellulose ester particles are commercially available from Rotuba Extruders, Inc. of Linden, N.J., under the trademark "Naturacell". Extrusion grade cellulose acetate particles are converted into extruded elements by methods well known in the art (see, e.g., WO2011/058319) and encapsulated within a base rod by the methods.

Fig. 2 is a perspective view of a cut-away portion of the second base rod 1 b. The second base rod 1b comprises a longitudinally extending generally cylindrical core 2b of tobacco smoke filtering material. The generally cylindrical core 2b is in the form of a cylindrical cellulose acetate plug having a length of 10mm and a circumference of about 25 mm. The generally cylindrical core 2b is made from cellulose acetate tow which has been gathered and compressed into the form of a rod by methods well known in the art. The second base rod 1b further comprises a second longitudinally extending element 3b formed of extruded cellulose acetate, the second longitudinally extending element 3b extending longitudinally through the substantially cylindrical core 2b such that one end of the element 3b can be seen at the second end 4b of the base rod. The continuous extruded cellulose acetate element 3b has an e-shaped cross-section and extends through the body of the rod 1b from one end to the other so that there is an e-shaped logo which can be seen at the second end 4b of the base rod. It will be appreciated that the e-shape is reversed at the other end of the base rod. The second base rod 1b may be manufactured by the method disclosed in WO 2011/058319. Methods for making extruded grade cellulose acetate powders are known (see, for example, US 4228246). Extruded grade cellulose ester particles are commercially available from Rotuba Extruders, Inc. of Linden, N.J., under the trademark "Naturacell". Extruded grade cellulose acetate particles are converted into extruded elements by methods well known in the art (see, e.g., WO2011/058319) and encapsulated within a base rod by the methods. It will be appreciated that the bar 1b is virtually identical to the bar 1a after being turned 180 degrees about a plane perpendicular to its longitudinal axis located halfway along its length.

Fig. 3 is a perspective view of a cut-away portion of the third base rod 1 c. The third base rod 1c comprises a longitudinally extending generally cylindrical core 2c of tobacco smoke filtering material. The generally cylindrical core 2c is in the form of a cylindrical cellulose acetate plug of length 20mm and circumference of about 25 mm. The generally cylindrical core 2c is made from cellulose acetate tow which has been gathered and compressed into the form of a rod by methods well known in the art.

Fig. 4 is a perspective view of a cut-away portion of a dual filter rod 10 according to another aspect of the present invention. The dual filter rod comprises a central third base rod 1c (e.g. the third base rod according to fig. 3). The central third base rod 1c abuts at its first end 101a to the second end 101b of the first base rod 1a (e.g. the base rod according to fig. 1). The first base rod 1a comprises a first longitudinally extending element 3a, which first longitudinally extending element 3a shows an e-shaped cross-section as can be seen at the first end 4a of the base rod 1 a. The central base rod also abuts at its second end 101c to a first end 101d of a second base rod 1b (e.g. a base rod according to fig. 2). The second base rod 1b comprises a second longitudinally extending element 3b, which second longitudinally extending element 3b shows an inverted e-shape as can be seen at the second end 4b of the base rod 1 b.

Fig. 5 is a perspective view of a cut-away portion of a dual filter rod 10 according to another aspect of the present invention. The dual filter rod comprises a central third base rod 1c (e.g. the third base rod according to fig. 3). The central third base rod 1c abuts at its first end 101a to the second end 101b of the first base rod 1a (e.g. the base rod according to fig. 1). The first base rod 1a comprises a first longitudinally extending element 3a, which can be seen at the first end 4a of the base rod 1a, which first longitudinally extending element 3a shows an e-shaped cross-section, which can be seen at the first end 4a of the base rod 1a (and the dual filter rod 10). Central thirdThe base rod also abuts at its second end 101c to a first end 101d of a second base rod 1b (e.g. a base rod according to fig. 2). The second base rod 1b comprises a second longitudinally extending element 3b, which can be seen at the second end 4b of the base rod 1b, which second longitudinally extending element 3b shows an inverted e-shape, which can be seen at the second end 4b of the base rod 1b (and the dual filter rod 10). Around the dual filter rod 10 is joined a double filter rod consisting of a base weight of 100g/m²The wrappage made of the heavy filter stick coil paper. The first end 14 of the wrap 13 extends beyond the first end 11 of the dual filter rod 10 and the second end 15 of the wrap 13 extends beyond the second end 12 of the dual filter rod 10 such that a tubular cavity or "groove" is provided at both ends 11, 12 of the dual filter rod 10.

Figure 5a is a perspective view of a cut-away portion of a dual filter product rod 1000 according to another aspect of the present invention. The dual filter rod 1000 includes: a first base rod 1a, the first base rod 1a comprising a first longitudinally extending generally cylindrical core 2a of tobacco smoke filtering material and a first element 3a (as shown in figure 1) extending longitudinally through the first core 2a of tobacco smoke filtering material; a second base rod 1b, the second base rod 1b comprising a second longitudinally extending generally cylindrical core 2b of tobacco smoke filtering material and a second element 3b (as shown in figure 2) extending longitudinally through the second core 2b of tobacco smoke filtering material; a third base rod 1c, the third base rod 1c comprising a third longitudinally extending substantially cylindrical core 2c (as shown in figure 3) of tobacco smoke filtering material, the third base rod 1c abutting at one end 101c to the first base rod 1 a; and a fourth base rod 1d, the fourth base rod 1d comprising a fourth longitudinally extending substantially cylindrical core 2d of tobacco smoke filtering material, the fourth base rod 1d being abutted to the second base rod 1b at one end 101 e. It will be appreciated that the fourth base bar is identical to the third base bar (i.e. identical to the bar of figure 3). The dual filter product rod comprises a basis weight of 100g/m²The wrap 13 of (a). As shown in fig. 5a, the end 4a of the first base bar 1a not abutting to the third base bar 1c is longitudinally spaced apart from the end 4b of the second base bar 1b not abutting to the fourth base bar 1 d. The wrap 13 is engaged around the third base rod 1c, the first base rod 1a, the second base rod 1b and the fourth base rod 1d, thereby defining a wrapped wrap between the first base rod 1a and the second base rod 1bThe central cavity 50.

As can be observed from the figure, the asymmetric e-shape (cross-section) of the first element at the end 4a (the end of the first base rod not attached to the third base rod) is a mirror image of the inverted e-shape (cross-section) of the second base rod at the end 4b not attached to the fourth base rod.

It will be appreciated that a dual filter product rod 1000 according to this aspect of the invention may be attached to a tobacco outer shell at each end (e.g. by endless end tipping) and subsequently cut aligned to a position half way up the central cavity 50, thereby providing two fluted filter cigarettes. The portion of the wrap overhanging the end of the first/second base bar after the wrap is cut forms (defines) a groove or cavity. As can be observed in figure 5a, the asymmetric cross-sections of the two elements in the dual filter product rod are mirror images of each other, so that when the final cut to provide two fluted filter cigarettes is made and the two cigarettes are oriented in the same direction (by turning one cigarette in the plane in which the cut is made), the e-shapes that can be seen at the ends of the two cigarettes are the same.

Figure 6 is a perspective view, partially cut away, of a tobacco smoke filter according to yet another aspect of the present invention. The filter comprises a longitudinally extending (e.g. generally cylindrical) core 16 of tobacco smoke filtering material, the longitudinally extending core 16 comprising a first (or second) base rod 1a/1b and a third base rod 1c (manufactured by the method described above) as shown in figure 1 or figure 2. The first or second base rod 1a, 1b comprises a longitudinally extending generally cylindrical core 2a/2b of tobacco smoke filtering material and an element 3a/3b extending longitudinally with respect to the core 2a/2b, the element 3a/3b being visible at a first end 4a/4b of the filter 16. The elements 3a/3b extending longitudinally with respect to the core 2a/2b have an asymmetric e-shaped cross-section. The tobacco smoke filter 16 also includes a basis weight of 100g/m²The wrap 13 surrounding the cylindrical core such that a first end 14 of the wrap 13 extends beyond a first end 17 of the core 2a/2b of filter material of the first or second base rod 1a, 1b about which the wrap 13 is joined, so as to be at the first end of the core 2a/2b of filter materialA tubular cavity or "groove" 18 is defined at 17. The second end 15 of the wrap 13 is substantially flush with the second end 19 of the core 2c of filter material (the second end 19 of the core 16) of the third base rod 1c about which the wrap 13 is joined.

It will be appreciated that the asymmetric e-shape of the component 3a/3b can be seen at the first end of the filter or filter component. Preferably, the (longitudinally extending) element is a press element. It will be appreciated that the longitudinally extending core of tobacco smoke filtering material comprises: a first core of tobacco smoke material (e.g. at a first end of the filter element), the first core comprising an element 3a/3b extending longitudinally about the core, the element 3a/3b being visible at the first end of the filter element; and a second core of tobacco smoke filtering material (the second core in this example not including elements extending longitudinally with respect to the core). The second core (here 1c) may be located at the opposite end to that of the first core where the first end of the filter element is visible.

Fig. 7 is a perspective view of a cut-away portion of the product rod 20. The product rod 20 includes a plurality of dual filter rods 10 spaced longitudinally from one another. Each dual filter rod 10 comprises a longitudinally extending generally cylindrical core 2 of tobacco smoke filtering material and comprises a first base rod 1a at a first end 4a of the dual filter rod 10, a second base rod 1b at a second end 4b of the dual filter rod 10, a third base rod 1c located longitudinally between the first and second base rods 1a, 1 b. A common wrap 13 is engaged around (and encircles) the plurality of dual filter rods 10 to define a wrapped cavity between adjacent dual filter rods in the product rod.

The product bar 20 may be produced by a method comprising the steps of:

advancing a continuous stream of dual filter rods 10 in a longitudinal direction 21, wherein the dual filter rods 10 in the longitudinally advancing stream are longitudinally spaced from one another, each dual filter rod comprising a longitudinally extending generally cylindrical core 2 of tobacco smoke filtering material; and

a common wrap 13 is provided around the continuous stream of dual filter rods 10. The filter 16 of fig. 6 may be produced by the following additional steps:

cutting the product rod 20 in alignment with a position 22 in one half of the third base rod; and

the product rod 20 is cut off in a position 23 aligned at one half of the space between the dual filter rods 10.

Figure 8 shows an apparatus according to the present invention for making the dual filter rod shown in figures 4, 5 and 5a and the tobacco smoke filter of figure 6 using conventional cigarette filter making machinery.

As shown in fig. 8, a first feed hopper 501 discharges a single pre-formed longitudinally extending substantially cylindrical first base rod 1a as described in fig. 1 into a continuous stream. The second feed hopper 502 provides a single pre-formed, longitudinally extending, substantially cylindrical second base rod 1b as described in fig. 2 into a continuous flow. The third feed hopper 503 provides a single, preformed, substantially cylindrical third base rod 1c as described in fig. 3 into a continuous flow. The continuous stream of base rods advances longitudinally along direction 510. The three feed hoppers release the base rod at the same rate as each other. The three feeder hoppers are arranged such that the third feeder hopper 503 is located between the first feeder hopper 501 and the second feeder hopper 502, so that the third base bar 1c is arranged in a continuous flow between the first base bar 1a and the second base bar 1 b.

The rods are picked up by the collation drum 520 in such a way that the collation drum 520 "pushes" the rods so that each first base rod 1a in the advancing stream is positioned with the second end 101b of the first base rod 1a abutting the first end 101a of the third base rod 1c and the second end 101c of the third base rod 1c abutting the first end 101d of the second base rod 1b to form a dual filter rod 10 so that there is a space between the first end 4a of the first base rod 1a of any given dual filter rod 10 and the second end 4b of the second base rod 1b of an adjacent dual filter rod 10.

As shown in fig. 8, a longitudinally advancing flow enters the fitment 530 where it is entrained onto a longitudinally advancing wrap substrate in the form of a sheet of paper having a basis weight of 80 gsm. The streams are arranged on a longitudinally advancing wrap substrate 13 in the following order-first base rod 1a + third base rod 1c + second base rod 1b + cavity + first base rod 1a etc. -to form a continuous wrapped product rod 20 comprising a plurality of dual filter rods 10 as shown in figure 7.

Subsequently, the continuous wrapped product rod 20 may be cut (by a rotary knife or the like). The continuous wrapped product rod 20 may be cut aligned at a position halfway through the third base rod 1c and/or the continuous wrapped product rod 20 may be cut aligned at a position halfway through the space 24 between the dual filter rods 10, thereby forming a dual filter rod 10 according to fig. 5, or a dual filter rod 1000 according to fig. 5a, or a filter 16 according to fig. 6. It will therefore be appreciated that if it is desired to provide a dual filter product rod 1000, or according to figure 5a, the wrapped product rod may be severed in register with a position at half of the third base rod 1c and cut again in register with a position at half of the next third base rod 1c in the stream to provide a dual filter product rod 1000.

Claims

1. A method of producing a tobacco smoke filter element, the method comprising the steps of:

longitudinally advancing a continuous stream of dual filter rods, wherein the dual filter rods in the longitudinally advancing stream are longitudinally spaced apart from one another, each dual filter rod comprising a longitudinally extending core of tobacco smoke filtering material, and wherein each dual filter rod comprises:

a first base rod located at a first end of the dual filter rod;

a second base rod located at a second end of the dual filter rod; and

a third base rod positioned longitudinally between the first base rod and the second base rod;

providing a common wrap around the continuous flow of dual filter rods to provide a product rod comprising a plurality of wrapped dual filter rods spaced longitudinally from one another within the product rod;

cutting said product rod at a position half way along the third base rod; and/or

Cutting said product rods at a location half way through the space between the dual filter rods; wherein the content of the first and second substances,

the first base rod includes: a first longitudinally extending core of tobacco smoke filtering material; and a first element extending longitudinally with respect to the first longitudinally extending core of tobacco smoke filtering material, the first element being visible at the first end of the dual filter rod; and

the second base rod includes: a second longitudinally extending core of tobacco smoke filtering material; and a second element extending longitudinally with respect to the second longitudinally extending core of tobacco smoke filtering material, the second element being visible at the second end of the dual filter rod;

wherein the cross-section of the first element visible at the first end of the dual filter rod is a mirror image of the cross-section of the second element visible at the second end of the dual filter rod.

2. The method of claim 1, wherein the cross-section of the first element and the cross-section of the second element are asymmetric.

3. A method according to claim 1 or 2, wherein the first element visible at the first end of the dual filter rod is a squeeze element and/or the second element visible at the second end of the dual filter is a squeeze element.

4. A method according to claim 1 or 2, wherein the common wrap comprises a basis weight of 40g/m²To 120g/m²The hard filter stick coil paper.

5. A method according to claim 1 or 2, wherein the dual filter rod comprises one or more additional base rods positioned longitudinally between the first and second base rods.

6. A method of producing a fluted tobacco smoke filter element according to any one of claims 1 to 4.

7. A filter cigarette comprising:

a filter comprising a filter element made by the method of any of claims 1 to 6, wherein the filter rod is connected to a wrapped tobacco rod in such a way that one end of the filter faces the tobacco.