Smoking article with modified smoke delivery
A smoking article (10) comprises a tobacco rod (12) wrapped with a paper wrapper (14), and a patch (16) of material between the tobacco rod and the paper wrapper that extends along the tobacco rod from or near the mouth end (B) to an intermediate point along the rod. The patch has a structure such that it provides a path for smoke from tobacco upstream of the patch to the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch, thus delivering smoke from the upstream part of the tobacco rod to the smoker more efficiently. The patch may also increase the static burn rate of the latter part of the smoking article.
The present invention relates to a smoking article with modified smoke delivery.
Smoking articles such as cigarettes comprise a rod of smokable material such as tobacco which is tightly wrapped in a paper wrapper (cigarette paper). A filter unit comprising one or more filter components may be joined to the wrapped tobacco rod using a tipping paper. For a uniform composition of tobacco rod, the smoke that is delivered through the tobacco rod from the burning tobacco, for any given puffing regime, is determined by three main factors: the amount of air drawn in through the coal during puffing (which depends upon the level of ventilation through the cigarette paper); the filtration of the smoke through the remaining unburnt part of the tobacco rod; and the speed of burn of the tobacco rod between puffs (smoulder rate). The smoke delivery from any single puff thus depends on the length of tobacco rod remaining, and for a standard puff volume taken from the end of the rod, will result in increased smoke delivery as the tobacco rod shortens.
The structure of the filter unit and any ventilation included therein (plus any ventilation that may be provided in the tipping paper) will modify the actual smoke/air combination delivered to the smoker. Hence, the features of the filter unit and the ventilation are typically adjusted to provide different brands of smoking article with different smoking properties as regards smoke delivery.
However, the structure of the tobacco rod also plays a part in the delivery of smoke to the smoker, owing to the passage of the smoke through the unburnt portion of the tobacco. Modification of the tobacco rod structure away from a uniform composition can therefore be used to further tailor smoke delivery.
SUMMARY OF THE INVENTIONAccordingly, a first aspect of the present invention is directed to a smoking article comprising: a tobacco rod; a paper wrapper encircling the tobacco rod; and a patch of material positioned between the tobacco rod and the paper wrapper and extending longitudinally along the tobacco rod from an intermediate point along the tobacco rod towards a mouth end of the tobacco rod, the material having a structure such that the patch provides a path for smoke from tobacco upstream of the patch to the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch.
This structure modifies the smoke flow compared to an equivalent smoking article without a such a patch. Smoke generated from tobacco in the first portion of the tobacco rod is provided with a preferential low resistance path through the smoking article when the smoker draws on the smoking article, so the smoke is delivered more efficiently. This improves the quality of the smoking experience for the smoker. An additional effect is also provided by the patch. The introduction of an open-structured material into the smoking article increases the static burn rate of the smoking article over the portion including the patch. The smoker can thus take fewer puffs from the second portion of the smoking article, thus receiving less smoke and a correspondingly reduced amount of the residues that can accumulate in the tobacco from the consumption of the first portion of the smoking article.
The length and position of the patch can be selected to provide the desired proportion of enhanced smoke delivery and reduced smoke delivery. For example, the patch may extend longitudinally from the intermediate point to the mouth end of the tobacco rod. Alternatively, the patch may extend longitudinally from the intermediate point to a second point between the intermediate point and the mouth end. The second point may be between 1% and 40% of the total length of the tobacco rod from the mouth end. A range of patch lengths are suitable, so that, for example, the patch may extend longitudinally over substantially 10% to 90% of the total length of the tobacco rod, or over substantially 40% to 80% of the total length of the tobacco rod.
The patch may extend substantially around the whole circumference of the tobacco rod. Alternatively, the patch may comprise one or more portions of material disposed around the circumference of the tobacco rod. These options can be chosen as desired to tailor the degree of smoke flow modification given by the patch.
A variety of combustible materials may be used for the patch. Any such material that provides the required low impedance smoke flow patch is suitable. The material may be chosen according to its structure with the aim of providing a particular level of smoke flow resistance, for example. In some embodiments, the patch may comprise a foam material.
In other embodiments, the patch may comprise a corrugated material having corrugations that extend substantially longitudinally along the tobacco rod. Various structures of corrugated material may be employed. For example, the corrugated material may have a laminate structure comprising a corrugated layer and a non-corrugated layer. The non-corrugated layer may be positioned between the tobacco rod and the corrugated layer, or between the corrugated layer and the paper wrapper. Alternatively, the corrugated material may have a laminate structure comprising a corrugated layer sandwiched between two non-corrugated layers. Also, a corrugated layer may be used alone with no non-corrugated layers.
In further embodiments, the patch may comprise an embossed material having indentations that extend substantially longitudinally along the tobacco rod, or a grooved material having grooves that extend substantially longitudinally along the tobacco rod, or a fibrous sheet material.
The patch may comprise at least one burn-enhancer to increase the static burn rate of the smoking article over the length comprising the patch. This can be used to tailor the static burn rate and consequently the number of puffs that can be taken from the latter part of the smoking article.
The patch may have a different colour from the paper wrapper and/or the tobacco rod. This allows detection of the patch by an optical defect detection system, sometimes used to provide quality control during smoking article manufacture.
The tobacco rod may have a reduced weight of tobacco per unit length under the patch compared to upstream of the patch. This both provides space to accommodate the patch, and further increases the static burn rate of the portion of the smoking article that includes the patch. Any suitable method can be employed to provide such a tobacco rod. For example, the reduced weight may be created by trimming tobacco from the outside of the tobacco rod, or by trimming tobacco from a tobacco bead from which the tobacco rod is to be cut.
The smoking article may further comprise a filter unit attached to the mouth end of the tobacco rod. The filter unit may be provided with one or more ventilation holes.
A second aspect of the present invention is directed to a method of fabricating a smoking article comprising: providing a rod of tobacco; disposing a patch of material over the rod of tobacco such that the patch extends longitudinally along the rod from an intermediate point along the rod towards a mouth end of the rod, the material having a structure and the patch being oriented such that, in the completed smoking article, the patch provides a path for smoke from tobacco upstream of the patch towards the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch to an intermediate position along the rod; and wrapping a paper wrapper around the rod.
Disposing the patch of material may comprise positioning the patch on the rod of tobacco before wrapping the paper wrapper around the rod. Alternatively, disposing the patch of material may comprise adhering the patch to an inner surface of the paper wrapper before wrapping the paper wrapper around the rod.
The method may comprise: trimming tobacco from the outside of the rod of tobacco over an area where the patch is to be disposed, thereby creating a reduced weight of tobacco per unit length; and disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed. Alternatively, the method may comprise trimming tobacco from the outside of a bead of tobacco over an area where the patch is to be disposed, thereby creating the reduced weight; cutting a rod of tobacco from the bead; and disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed.
For a better understanding of the invention and to show how the same may be carried into effect reference is now made by way of example to the accompanying drawings in which:
The present invention aims to provide a smoking article such as a cigarette that delivers smoke to the smoker with improved efficiency for a first portion of the smoking article, and also generates less smoke than a conventional smoking article from all or part of the remainder of the smoking article. To address this, a patch of material that allows a more free passage of smoke therethrough than does the tobacco of the smoking article is positioned under part of the outer wrapping paper of the smoking article.
In accordance with the invention, the smoking article 10 is modified from the conventional design by the inclusion of a patch 16 of material arranged between the tobacco rod 12 and the paper wrapper 14. The patch extends from the mouth end B (in this example) in a longitudinal direction along the tobacco rod to a point intermediate between the mouth end B and the end A intended to be lit. The patch is highly porous to the flow of air and smoke in a direction along the length of the smoking article (and hence will typically be formed from a material with a relatively open structure or be constructed so that the patch itself provides as open structure), so that it offers a path for smoke generated by the lit end of the smoking article and drawn through the smoking article during smoking that is less resistive to the flow of smoke than a path through the tobacco that is overlain by the patch. Hence, smoke produced by burning tobacco from the part of the tobacco rod upstream of the patch has a more free passage to the mouth end through the patch material than through the tobacco.
When the burn line of the lit smoking article 10 reaches the patch 16, the open structure of the patch increases the static burn rate or smoulder rate of the smoking article (this being the rate at which material of the smoking article burns away in the absence of puffs by the smoker). This reduces the number of puffs that can be taken from the second portion of the smoking article (the portion including the patch), so that the overall amount of smoke delivered to the smoker from the second portion is reduced compared to that delivered from a conventional smoking article without a patch. This is beneficial in that a larger amount of the residues from the first upstream portion of the smoking article that accumulate in the tobacco of the downstream portion is burnt away and a smaller amount delivered to the smoker.
The increased burn rate given by the open structure of the patch 16 can be further enhanced by providing the material from which the patch is fabricated with one or more burn enhancers. These are substances that increase the rate of burning of a material to which they are applied (as a surface layer or by impregnation, for example). The amount and type of burn enhancer can be chosen in conjunction with the types of patch material, tobacco and paper wrapper to provide a desired burn rate Suitable burn enhancers include citrates, such as sodium or potassium citrate. Burn rate additives such as sodium or potassium salts, acetate and tartrate, mono-ammonium phosphate, and di-sodium hydrogen phosphate, sodium and potassium citrate and sodium acetate may also be used, as may any burn enhancers/additives known to those skilled in the art.
Overall, therefore, a smoking article provided with a patch according to the invention has increased smoke delivery from a first portion of the tobacco rod and decreased smoke delivery from a second portion of the tobacco rod, compared to an equivalent smoking article without a patch.
Also, the patch need not extend all the way to the mouth end of the smoking article. A patch that terminates short of the mouth end will still provide the above-described effects of increased smoke delivery from the portion upstream of the patch and decreased smoke delivery from the portion including the patch. The remaining portion downstream of the patch will provide smoke delivery corresponding to that from a conventional smoking article with no patch. Any spacing between the patch and mouth end may be chosen, to give the desired overall balance between the three types of smoke delivery. For example, the patch may extend from an intermediate upstream point along the tobacco rod to a point in the range 1% to 40% of the total length of the tobacco rod from the mouth end.
To provide the maximum smoke delivery modification effect for a given length of patch, the patch should extend around the full circumference of the tobacco rod.
Further variation in the amount of smoke delivery modification can be provided by using a patch 16 that does not extend all the way around the tobacco rod 12. In such an embodiment, the patch 16 comprises one or more separate portions of patch material. For more than one portion, the portions are spaced apart around the circumference of the tobacco rod 12. For even burning of the smoking article, the portions can be symmetrically spaced around the circumference.
The patch can be fabricated from any material that has appropriate combustion and compositional properties for inclusion in a smoking article and which provides the required low resistance passage for smoke propagation. Materials which inherently have the desired structure can be used, such as a fibrous sheet material having a sufficiently open structure. The fibrous sheet material may be cellulosic sheet material or tobacco-containing sheet material such as reconstituted tobacco sheet material or tobacco substitute sheet material, for example. Alternatively, materials can be specifically fabricated so as to have a suitable open structure.
For example, a foamed material can be used, wherein the bubbles formed in the foaming process provide an open structure and a substantially free path for smoke. Examples of suitable foamed materials are extruded tobacco reconstituted materials and foamed band-cast tobacco sheet.
In other embodiments, the patch may comprise corrugated material, such as corrugated paper or cardboard. By arranging the corrugations or ridges/troughs in the material to run lengthwise along the tobacco rod, a plurality of parallel longitudinal open passages are provided around the circumference of the tobacco rod. A number of configurations of corrugated material can be used.
Patch materials fabricated to have a similar structure to corrugated material may also be used, for example a pair of flat layers having a plurality of parallel ribs extending between the layers. When the patch is applied to the tobacco rod, the ribs run longitudinally along the length of the rod, and extend radially between the two flat layers. The term “corrugated material” is intended to include structurally similar patch materials that provide a plurality of parallel longitudinal smoke paths.
Alternatively, embossed material may be used for the patch, having a pattern of indentations embossed into its surface and arranged to provide paths along the length of the patch when positioned in the smoking article. The indentations may be substantially straight and arranged parallel to the length of the tobacco rod, providing a structure largely equivalent to a single-sided corrugated patch. Alternatively, the indentations may be curved, or straight but arranged at an angle to the length of the tobacco rod. Such configurations provide smoke paths that are longer than the longitudinal extent of the patch, which can be used to further modify the smoke delivery from the tobacco upstream of the patch.
A similar effect to embossed material can be achieved by using a grooved material, by arranging the grooves to provide paths for smoke upstream of the patch.
The patch may be coloured to assist recognition by defect detection systems commonly employed during smoking article manufacture to identify completed or partially completed smoking articles that have one or more missing or defective components. Such detection systems may be optical systems that monitor the amount of light at one or more wavelengths that is transmitted by or reflected from various components. Thus, if the patch is a different colour from the tobacco and/from the paper wrapper, its presence or absence from the completed smoking article can be determined using an optical detection system.
In many examples, in order to provide a useful level of modification to the smoke delivery, the patch will have a thickness that is much greater than the typical thickness of a standard paper wrapper (cigarette paper). The thickness of the patch may be between 5 and 50 times the thickness of the paper wrapper, for example. This corresponds to a patch with a thickness substantially in the range 0.2 mm to 2 mm. During fabrication of the smoking article, the patch may be positioned around the tobacco rod before the paper wrapper is applied, or the patch may be adhered to the paper wrapper before the latter is wrapped around the tobacco rod (in a similar manner to the technique described in WO 2005/082180 for providing a web of adsorbent material and flavourant under the wrapper of a smoking article). In either case, to achieve a substantially constant diameter along the length of the smoking article, the tobacco under the patch will be compressed. The tobacco in the upstream portion of the tobacco rod will therefore be less dense than the tobacco in the downstream portion of the tobacco rod. This will further affect both the relative resistance to smoke flow offered by the tobacco and the patch, and the static burn rate of the second portion of the smoking article.
To address these additional effects, it is proposed according to a further embodiment that the width of the tobacco rod be reduced under the patch, to give a reduced weight of tobacco per unit length under the patch compared to upstream of the patch. This can be achieved by removing some tobacco from the tobacco rod, for example by using one or more trimmer (ecreteur) discs (such as are conventionally used to size, shape and tidy the tobacco bead in smoking article manufacture) to cut away a portion of tobacco from the continuous bead of tobacco from which the rods are cut.
Thus far, the smoking articles described herein have comprised tobacco rods, wrapping papers and patches, thus providing filterless smoking articles. In such a case, a colour or other distinguishing mark or feature may be applied to the outside of the wrapper at the mouth end of the finished smoking article, to assist the consumer in correctly identifying the mouth end before smoking. Alternatively, the tobacco rods may be provided with filter units to provide filter-tipped smoking articles in the conventional manner, wherein a filter unit is joined to the mouth end of a wrapped tobacco rod by a tipping paper. The filter unit may have any configuration, including single component or multiple component, and may or may not be provided with ventilation such as a circumferential row or zone of ventilation holes made by on-line laser machining or provided by pre-perforations. Thus, the term “smoking article” as used herein is intended to include filterless smoking articles comprising a tobacco rod with no filter unit, filter-tipped smoking articles comprising a tobacco rod with an attached filter unit, and tobacco rods without filters but to which a filter unit may be attached by a later fabrication stage to form a filter-tipped smoking article.
The term “tobacco” as used herein is intended to be understood as including smokable material in general, including tobacco material (such as stem, lamina, tobacco dust, cut tobacco and expanded tobacco), reconstituted tobacco and substitute tobacco materials.
Claims
1. A smoking article comprising:
- a tobacco rod;
- a wrapper around the tobacco rod; and
- a patch of material positioned between the tobacco rod and the wrapper and extending longitudinally along the tobacco rod from an intermediate point along the tobacco rod towards a mouth end of the tobacco rod, the material having structure such that the patch provides a path for smoke from tobacco upstream of the patch towards the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch, and wherein the patch comprises at least one burn-enhancer to increase the static burn rate of the smoking article over the length comprising the patch.
2. The smoking article according to claim 1, wherein the patch extends longitudinally from the intermediate point to the mouth end of the tobacco rod.
3. The smoking article according to claim 1, wherein the patch extends longitudinally from the intermediate point to a second point between the intermediate point and the mouth end.
4. The smoking article according to claim 3, wherein the second point is between 1% and 40% of the total length of the tobacco rod from the mouth end.
5. The smoking article according to claim 1, wherein the patch extends longitudinally over substantially 10% to 90% of the total length of the tobacco rod.
6. The smoking article according to claim 5, wherein the patch extends longitudinally over substantially 40% to 80% of the total length of the tobacco rod.
7. The smoking article according to claim 1, wherein the patch extends substantially around the whole circumference of the tobacco rod.
8. The smoking article according to claim 1, wherein the patch comprises one or more portions of material disposed around the circumference of the tobacco rod.
9. The smoking article according to claim 1, wherein the patch comprises a foam material.
10. The smoking article according to claim 1, wherein the patch comprises a corrugated material having corrugations that extend substantially longitudinally along the tobacco rod.
11. The smoking article according to claim 10, wherein the corrugated material has a laminate structure comprising a corrugated layer and a non-corrugated layer.
12. The smoking article according to claim 11, wherein the non-corrugated layer is positioned between the tobacco rod and the corrugated layer.
13. The smoking article according to claim 49, wherein the non-corrugated layer is positioned between the corrugated layer and the paper wrapper.
14. The smoking article according to claim 10, wherein the corrugated material has a laminate structure comprising a corrugated layer sandwiched between two noncorrugated layers.
5. The smoking article according to claim 1, wherein the patch comprises an embossed material having indentations that extend substantially longitudinally along the tobacco rod.
16. The smoking article according to claim 1, wherein the patch comprises a grooved material having grooves that extend substantially longitudinally along the tobacco rod.
17. The smoking article according to claim 1, wherein the patch comprises a fibrous sheet material.
18. The smoking article according to claim 1, wherein the patch has a color different from the wrapper and the tobacco rod.
19. The smoking article according to claim 1, wherein the tobacco rod has a reduced weight of tobacco per unit length under the patch compared to upstream of the patch.
20. The smoking article according to claim 19, wherein the reduced weight is created by trimming tobacco from the outside of the tobacco rod.
21. The smoking article according to claim 19, wherein the reduced weight is created by trimming tobacco from a tobacco bead from which the tobacco rod is to be cut.
22. The smoking article according to claim 1, wherein the smoking article further comprises a filter unit attached to the mouth end of the tobacco rod.
23. The smoking article according to claim 22, wherein the filter unit is provided with one or more ventilation holes.
24. A method of fabricating a smoking article comprising:
- providing a rod of tobacco;
- disposing a patch of material over the rod of tobacco such that the patch extends longitudinally along the rod from an intermediate point along the rod towards a mouth end of the rod, the material having a structure and the patch being oriented such that, in the completed smoking article, the patch provides a path for smoke from tobacco upstream of the patch towards the mouth end that has less resistance to smoke flow than a path through the tobacco under the patch, wherein the patch comprises at least one burn-enhancer to increase the static burn rate of the smoking article over the length comprising the patch; and
- wrapping a wrapper around the rod.
25. The method according to claim 24, wherein disposing the patch of material comprises positioning the patch on the rod of tobacco before wrapping the wrapper around the rod.
26. The method according to claim 50, wherein disposing the patch of material comprises adhering the patch to an inner surface of the paper wrapper before wrapping the wrapper around the rod.
27. The method according to claim 24, wherein the patch extends longitudinally from the intermediate point to the mouth end of the rod of tobacco.
28. The method according to claim 24, wherein the patch extends longitudinally from the intermediate point to a second point between the intermediate point and the mouth end.
29. The method according to claim 28, wherein the second point is between 1% and 40% of the total length of the rod of tobacco from the mouth end.
30. The method according to claim 24, wherein the patch extends longitudinally over substantially 10% to 90% of the total length of the rod.
31. The method according to claim 30, wherein the patch extends longitudinally over substantially 40% to 80% of the total length of the rod.
32. The method according to claim 24, wherein the patch extends substantially around the whole circumference of the rod of tobacco.
33. The method according to claim 24, wherein the patch comprises one or more portions of material disposed around the circumference of the rod of tobacco.
34. The method according to claim 24, wherein the patch comprises a foam material.
35. The method according to claim 50, wherein the patch comprises a corrugated material having corrugations, the patch being disposed such that the corrugations extend substantially longitudinally along the rod of tobacco.
36. The method according to claim 35, wherein the corrugated material has a laminate structure comprising a corrugated layer and a non-corrugated layer.
37. The method according to claim 36, wherein the patch is disposed such that the non-corrugated layer is positioned between the tobacco rod and the corrugated layer.
38. The method according to claim 36, wherein the patch is disposed such that the noncorrugated layer is positioned between the corrugated layer and the paper wrapper.
39. The method according to claim 35, wherein the corrugated material has a laminate structure comprising a corrugated layer sandwiched between two noncorrugated layers.
40. The method according to claim 24, wherein the patch comprises an embossed material, the patch disposed such that indentations in the material extend substantially longitudinally along the rod of tobacco.
41. The method according to claim 24, wherein the patch comprises a grooved material, the patch disposed such that the grooves extend substantially longitudinally along the rod of tobacco.
42. The method according to claim 24, wherein the patch comprises a fibrous sheet material.
43. The method according to claim 50, wherein the patch has a color different from the paper wrapper and the rod of tobacco.
44. The method according to claim 24, wherein the rod of tobacco has a reduced weight of tobacco per unit length under the patch compared to upstream of the patch.
45. The method according to claim 24, further comprising:
- trimming tobacco from outside of the rod of tobacco over an area where the patch is to be disposed, thereby creating a reduced weight; and
- disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed.
46. The method according to claim 24, further comprising:
- trimming tobacco from outside of a bead of tobacco over an area where the patch is to be disposed, thereby creating a reduced weight;
- cutting a rod of tobacco from the bead; and
- disposing the patch over the rod of tobacco so that the patch covers the area from which tobacco has been trimmed.
47. The method according to claim 24, further comprising attaching a filter unit to the smoking article.
48. The method according to claim 47, wherein the filter unit is provided with one or more ventilation holes.
49. The smoking article according to claim 11, wherein the wrapper is a paper wrapper.
50. The method according to claim 24, wherein the wrapper is a paper wrapper.
Type: Application
Filed: Sep 18, 2008
Publication Date: Nov 4, 2010
Inventor: Richard Fiebelkorn (Southampton)
Application Number: 12/678,485
International Classification: A24C 1/26 (20060101); A24D 1/02 (20060101);