MULTI-SEGMENT COMPONENT WITH INTUMESCENT COATING

Abstract

A multi-segment component for an aerosol-generating article is provided, the multi-segment component including: a combustible heat source; an aerosol-forming substrate downstream of the combustible heat source; and a wrapper circumscribing a rear portion of the combustible heat source and at least a front portion of the aerosol-forming substrate, a front portion of the combustible heat source extending beyond the wrapper so that the front portion of the combustible heat source is exposed during use; and an intumescent coating on all or part of the front portion of the combustible heat source, the intumescent coating being configured to form a heat insulating layer on the front portion of the combustible heat source in response to heating by the combustible heat source.

Claims

1.-13. (canceled)

14. A multi-segment component for an aerosol-generating article, the multi-segment component comprising: a combustible heat source; an aerosol-forming substrate downstream of the combustible heat source; and a wrapper circumscribing a rear portion of the combustible heat source and at least a front portion of the aerosol-forming substrate, wherein a front portion of the combustible heat source extends beyond the wrapper so that the front portion of the combustible heat source is exposed during use; and an intumescent coating on all or part of the front portion of the combustible heat source, the intumescent coating being configured to form a heat insulating layer on the front portion of the combustible heat source in response to heating by the combustible heat source.

15. The multi-segment component according to claim 14, wherein the intumescent coating is provided on substantially an entire outer surface of the front portion of the combustible heat source.

16. The multi-segment component according to claim 14, wherein the intumescent coating is provided in a discontinuous pattern on the front portion of the combustible heat source.

17. The multi-segment component according to claim 16, wherein the discontinuous pattern comprises one or more lines, rings, dots, or other discrete geometric shapes of intumescent material, or any combination thereof.

18. The multi-segment component according to claim 14, wherein the intumescent coating is provided only on the front portion of the combustible heat source.

19. The multi-segment component according to claim 14, wherein the intumescent coating is provided on substantially an entire length of the combustible heat source.

20. The multi-segment component according to claim 19, wherein the intumescent coating comprises a first intumescent coating on the front portion of the combustible heat source, and a second intumescent coating on the rear portion of the combustible heat source, and wherein the first and the second intumescent coatings are formed from different intumescent materials.

21. The multi-segment component according to claim 14, wherein the intumescent coating has an expansion ratio of at least about 1.5:1, when heated from 20 degrees Celsius to 700 degrees Celsius at 1 atmosphere of pressure.

22. The multi-segment component according to claim 14, wherein the intumescent coating has an expansion ratio of from about 1.5:1 to about 8:1, when heated from 20 degrees Celsius to 700 degrees Celsius at 1 atmosphere of pressure.

23. The multi-segment component according to claim 14, wherein the intumescent coating has a thickness of from about 100 micrometres to about 2 millimetres.

24. The multi-segment component according to claim 14, wherein the intumescent coating has a thickness of from about 200 micrometres to about 1 millimetre.

25. The multi-segment component according to claim 14, wherein the heat insulating layer formed by the intumescent coating is porous.

26. The multi-segment component according to claim 14, wherein the front portion of the combustible heat source has a length of at least 25 percent of a total length of the combustible heat source.

27. The multi-segment component according to claim 14, wherein the wrapper comprises one or more layers of heat-conductive material.

28. An aerosol-generating article comprising a multi-segment component according to claim 14, and a mouthpiece disposed downstream of the multi-segment component.

Description

[0164] The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

[0165] FIG. 1 shows a schematic longitudinal cross-sectional view of an aerosol-generating article having a multi-segment component according to a first embodiment of the invention;

[0166] FIG. 2 shows a schematic longitudinal cross-sectional view of an aerosol-generating article having a multi-segment component according to a second embodiment of the invention;

[0167] FIG. 3 shows a schematic longitudinal cross-sectional view of an aerosol-generating article having a multi-segment component according to a third embodiment of the invention;

[0168] FIG. 4 shows a schematic longitudinal cross-sectional view of an aerosol-generating article having a multi-segment component according to a fourth embodiment of the invention;

[0169] FIG. 5 shows a schematic longitudinal cross-sectional view of an aerosol-generating article having a multi-segment component according to a fifth embodiment of the invention;

[0170] FIGS. 6 to 9 show schematic longitudinal views of combustible heat sources comprising an intumescent coating on at least the front portion of a combustible heat source, for use in a multi-segment component according to the present invention.

[0171] The aerosol-generating article 2 according to the first embodiment of the invention shown in FIG. 1 comprises a multi-component segment 50 and a mouthpiece 18 downstream of the multi-component segment 50. The multi-component segment 50 comprises a blind combustible heat source 4 having a front face 6 and an opposed rear face 8, an aerosol-forming substrate 10 and a transfer element 12. The multi-component segment 50 further comprises an aerosol-cooling element 14 and a spacer element 16 disposed downstream of the aerosol-forming substrate 10.

[0172] The blind combustible heat source 4 is a blind carbonaceous combustible heat source and is located at the distal end of the aerosol-generating article 2. As shown in FIG. 1, a non-combustible substantially air impermeable barrier 22 in the form of a disc of aluminium foil is provided between the rear face 8 of the blind combustible heat source 4 and the aerosol-forming substrate 10. The barrier 22 is applied to the rear face 8 of the blind combustible heat source 4 by pressing the disc of aluminium foil onto the rear face 8 of the blind combustible heat source 4 and abuts the rear face 8 of the combustible carbonaceous heat source 4 and the aerosol-forming substrate 10.

[0173] In other embodiments of the invention (not shown), the non-combustible substantially air impermeable barrier 22 between the rear face 8 of the blind combustible heat source 4 and the aerosol-forming substrate 10 may be omitted.

[0174] The aerosol-forming substrate 10 is located immediately downstream of the barrier 22 applied to the rear face 8 of the blind combustible heat source 4. The aerosol-forming substrate 10 comprises a cylindrical plug of homogenised tobacco-based material 24 including an aerosol former such as, for example, glycerine, wrapped in plug wrap 26.

[0175] The transfer element 12 is located immediately downstream of the aerosol-forming substrate 10 and comprises a cylindrical open-ended hollow cellulose acetate tube 28.

[0176] The aerosol-cooling element 14 is located immediately downstream of the transfer element 12 and comprises a gathered sheet of biodegradable polymeric material such as, for example, polylactic acid.

[0177] The spacer element 16 is located immediately downstream of the aerosol-cooling element 14 and comprises a cylindrical open-ended hollow paper or cardboard tube 30.

[0178] The mouthpiece 18 is located immediately downstream of the spacer element 16. As shown in FIG. 1, the mouthpiece 18 is located at the proximal end of the aerosol-generating article 2 and comprises a cylindrical plug of suitable filtration material 32 such as, for example, cellulose acetate tow of very low filtration efficiency, wrapped in filter plug wrap 34.

[0179] As shown in FIG. 1, the aerosol-generating article 2 further comprises a single heat-conducting element 36 of suitable material such as, for example, aluminium foil, overlying a rear portion of the blind combustible heat source 4 and a front portion of the aerosol-forming substrate 10. In this embodiment, the single heat-conducting element 36 does not overlie any of the transfer element 12.

[0180] In other embodiments of the invention (not shown), the single heat-conducting element 36 may overlying a rear portion of the blind combustible heat source 4 and the entire length of the aerosol-forming substrate 10 and the entire length of the transfer element 12.

[0181] In other embodiments of the invention (not shown), the transfer element 12 may extend beyond the single heat-conducting element 36 in the downstream direction. That is the single heat-conducting element 36 may overlie only a front portion of the transfer element 12.

[0182] The single heat-conducting element 36 is circumscribed by a wrapper 38 of heat-insulative sheet material such as, for example, cigarette paper, of low air permeability, which is wrapped around the aerosol-forming substrate 10, transfer element 12 and a rear portion of the blind combustible heat source 4 to form a multi-segment component 50 of the aerosol-generating article 2.

[0183] The aerosol-cooling element 14, spacer element 16 may be circumscribed by a further wrapper (not shown). Alternatively, the aerosol-cooling element 14, spacer element 16 and mouthpiece 18 may be individual segments that are held together and connected to the multi-segment component 50 by the outer wrapper 20.

[0184] In other embodiments (not shown) the wrapper 38 may extend downstream of the transfer element 12 to circumscribe other components of the aerosol-generating article 2, such as the aerosol-cooling element 14 and the spacer element 16 which are then incorporated into the multi-segment component. The mouthpiece 18 may then be connected at the downstream end of the multi-segment component by outer wrapper 20, or by an additional wrapper or a band of tipping paper (not shown).

[0185] In the aerosol-generating article 2 according to the first embodiment of the invention shown in FIG. 1, the single heat-conducting element 36 and the wrapper 38 extend to approximately the same position on the blind combustible heat source 4 in the upstream direction such that the upstream ends of the single heat-conducting element 36 and the wrapper 38 are substantially aligned over the blind combustible heat source 4.

[0186] The portion of the blind combustible heat source 4 circumscribed by the wrapper 38 may be referred to as the rear portion of the combustible heat source 4. The portion of the combustible heat source 4 which extends beyond the wrapper 38 so that it is exposed during use may be referred to as the front portion of the combustible heat source 4

[0187] It will be appreciated that in other embodiments of the invention (not shown), the wrapper 38 may extend beyond the single heat-conducting element 36 in the upstream direction.

[0188] The aerosol-generating article 2 comprises one or more air inlets 38 around the periphery of the aerosol-forming substrate 10.

[0189] As shown in FIG. 1, a circumferential arrangement of air inlets 40 is provided in the plug wrap 26 of the aerosol-forming substrate 10, the wrapper 38 and the single heat-conducting element 36 to admit cool air (shown by dotted arrows in FIG. 1) into the aerosol-forming substrate 10.

[0190] The aerosol-generating article 2 further comprises an intumescent coating 42 provided on the combustible heat source 4. In the embodiment shown in FIG. 1, the intumescent coating 42 is provided on substantially the entire length of the combustible heat source 4. The intumescent coating 42 is provided on substantially the entire outer surface of the combustible heat source 4. The intumescent coating 42 is not provided on the front end face of the combustible heat source 4. In this embodiment, on the rear portion of the combustible heat source 4, the intumescent coating 42 is arranged on an inner surface of the heat-conducting element 36 such that it is indirect contact with the combustible heat source 4. In other examples (not shown), the intumescent coating 42 may be in contact with the rear portion of the combustible heat source 4 indirectly, for example via the heat-conducting element 36. The intumescent coating 42 circumscribes the combustible heat source 4 and is arranged to expand in response to heat from the combustible heat source 4. The intumescent coating 42 is formed from an intumescent inorganic glue. Suitable intumescent inorganic glues include sodium silicate glues, such as those available from PQ Corporation of Malvern, Pa., US.

[0191] The multi-segment component 50 may further comprise a removable cap (not shown) at its distal end and directly adjacent to the heat source 4. For example, the removable cap may comprise a central portion including a desiccant, such as glycerine, to absorb moisture as compared to the heat source, which is wrapped in a portion of one or both of the outer wrapper 20 and the wrapper 38 and connected to the rest of that wrapper along a line of weakness comprising a plurality of perforations in the wrapper. In such examples, to use the aerosol-generating article, the user removes the removable cap by transversely compressing the cap by pinching it between thumb and finger. By compressing the cap, sufficient force is provided to the line of weakness to locally break the wrapper by which the cap is connected. The user then removes the cap by twisting the cap to break the remaining portion of the line of weakness. When the cap is removed the heat source is partially exposed which enables the user to light the aerosol-generating article.

[0192] In use, a user ignites the blind combustible heat source 4 of the aerosol-generating article 2 according to the first embodiment of the invention and then draws on the mouthpiece 18. When a user draws on the mouthpiece 18, air (shown by dotted arrows in FIG. 1) is drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the air inlets 40.

[0193] The front portion of the aerosol-forming substrate 10 is heated by conduction through the rear face 8 of the blind combustible heat source 4 and the barrier 22.

[0194] The heating of the aerosol-forming substrate 10 by conduction releases glycerine and other volatile and semi-volatile compounds from the plug of homogenised tobacco-based material 24. The compounds released from the aerosol-forming substrate 10 form an aerosol that is entrained in the air drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the air inlets 40 as it flows through the aerosol-forming substrate 10. The drawn air and entrained aerosol (shown by dashed arrows in FIG. 1) pass downstream through the transfer element 12, aerosol-cooling element 14 and spacer element 16, where they cool and condense. The cooled drawn air and entrained aerosol pass downstream through the mouthpiece 18 and are delivered to the user through the proximal end of the aerosol-generating article 2 according to the first embodiment of the invention. The non-combustible substantially air impermeable barrier 22 on the rear face 8 of the blind combustible heat source 4 isolates the blind combustible heat source 4 from air drawn through the aerosol-generating article 2 such that, in use, air drawn through the aerosol-generating article 2 does not come into direct contact with the blind combustible heat source 4.

[0195] During heating of the intumescent coating 42 by the combustible heat source 4, the intumescent coating 42 expands. The expanded intumescent coating 42 provides a heat insulating layer on the outer surface of the combustible heat source 4. This reduces the temperature of the external surface of the aerosol-generating article 2 and facilitates a reduction in the potential risk of heat damage to adjacent materials caused by improper handling of the aerosol-generating article 2.

[0196] The intumescent coating 42 has an unexpanded thickness of from about 0.1 mm to about 2 mm and has an expansion ratio of from about 1.5:1 to about 8:1.

[0197] Features of further embodiments of the invention, described below, which are the same as features described above in relation to the first embodiment of the invention shown in FIG. 1, are identified using common reference numerals.

[0198] An aerosol-generating article according to a second embodiment of the invention is shown in FIG. 2. In the second embodiment, the intumescent coating comprises a first intumescent coating 43 provided on a front portion of the combustible heat source 4, and a second intumescent coating 44 provided on a rear portion of the combustible heat source 4. Together, the first 43 and second 44 intumescent coatings are provided on substantially the entire outer surface of the combustible heat source 4. As a result, the substantially the entire outer surface of the combustible heat source 4 is provided with an intumescent coating 43, 44. The first 43 and second 44 intumescent coatings are formed from different intumescent materials. The material used in the first intumescent coating 43 is selected to optimise the heat insulating properties of the first intumescent coating 43, while the material used in the second intumescent coating 44 is selected to optimise the adhesive or retentive properties of the second intumescent coating so as to securely fix the combustible heat source in place.

[0199] An aerosol-generating article according to a third embodiment of the invention is shown in FIG. 3. In the third embodiment, the intumescent coating comprises a first intumescent coating 43 provided on a front portion of the combustible heat source 4 and a second intumescent coating 44 provided on a rear portion of the combustible heat source 4. The first intumescent coating 43 is provided in a discontinuous pattern, for example, as a series of rings about the circumferential surface of the front portion of the combustible heat source 4. As in the second embodiment, the first 43 and second 44 intumescent coatings are formed from different materials and the second intumescent coating 44 is provided on substantially the entire outer surface of the rear portion of the combustible heat source 4.

[0200] An aerosol-generating article according to a fourth embodiment of the invention is shown in FIG. 4. In the fourth embodiment, an intumescent coating 42 is provided on both the front portion of the combustible heat source 4 and the rear portion of the combustible heat source 4. The intumescent coating 42 is provided on substantially the entire outer surface of the rear portion of the combustible heat source 4. The intumescent coating 42 is provided in a discontinuous pattern on the front portion of the combustible heat source 4.

[0201] An aerosol-generating article according to a fifth embodiment of the invention is shown in FIG. 5. In the fifth embodiment, an intumescent coating 42 is provided on only the front portion of the combustible heat source 4. The intumescent coating 42 is provided on substantially the entire outer surface of the front portion of the combustible heat source 4. The rear portion of the combustible heat source 4 is not provided with an intumescent coating. Instead, the single heat-conducting element 36 is in direct contact with the rear portion of the combustible heat source 4.

[0202] FIGS. 6 to 9 show combustible heat sources for use in a multi-segment component according to the present invention.

[0203] In the embodiment shown in FIG. 6, an intumescent coating 42 is provided on only the front portion of a combustible heat source 4. The intumescent coating 42 is provided on substantially the entire outer surface of the front portion of the combustible heat source 4. The rear portion of the combustible heat source 4 is not provided with an intumescent coating. The intumescent coating 42 is provided as a continuous layer. The intumescent coating 42 is not provided on substantially the entire length of the combustible heat source 4.

[0204] In the embodiments shown in FIGS. 7 to 9, an intumescent coating 42 is provided as a discontinuous pattern on substantially the entire outer surface of the front portion of the combustible heat source 4.

[0205] In the embodiments shown in FIG. 7, an intumescent coating 42 is provided as a series of parallel stripes. In FIGS. 7a and 7b, the intumescent coating 42 is provided on only the front portion of the combustible heat source 4. The intumescent coating 42 is not provided on substantially the entire length of the combustible heat source 4. In FIG. 7a, the intumescent coating 42 is provided as a series of longitudinal parallel stripes. In FIG. 7b, the intumescent coating 42 is provided as a series of transverse parallel stripes.

[0206] In FIG. 7c, an intumescent coating 42 is provided as a series of longitudinal stripes along the entire length of the combustible heat source 4. In FIG. 7c, the intumescent coating is provided in a discontinuous pattern on substantially the entire outer surface of the front portion of the combustible heat source, and on substantially the entire length of the combustible heat source.

[0207] In the embodiment shown in FIG. 8, an intumescent coating 42 is provided as a series of dots on the front portion of the combustible heat source 4. The rear portion of the combustible heat source 4 is not provided with an intumescent coating. The intumescent coating 42 is not provided on substantially the entire length of the combustible heat source 4.

[0208] In the embodiment shown in FIG. 9, an intumescent coating 42 is provided on both the front portion and the rear portion of a combustible heat source 4. The intumescent coating 42 is provided in a grid pattern. The intumescent coating 42 is provided on substantially the entire length of the combustible heat source 4. The intumescent coating 42 is provided on substantially the entire outer surface of the combustible heat source 4.

[0209] The specific embodiments and examples described above illustrate but do not limit the invention. It is to be understood that other embodiments of the invention may be made and the specific embodiments and examples described herein are not exhaustive.