Aerosol-Generating Article Wrapper Comprising Heat Sensitive Indication Means

Abstract

A wrapper 10 for an aerosol-generating article includes at least one coated surface area and at least one non-coated surface area, wherein the coating of the at least one coated surface area of the wrapper is heat-sensitive, wherein the coating indicates heat application by a permanent color change. An aerosol generating article includes such a wrapper. A method for producing an aerosol generating article includes such a wrapper by printing a polymer on parts of the wrapper by flexography.

Claims

1. A wrapper for an aerosol-generating article comprising at least one coated surface area coated with a heat-sensitive coating arranged for indicating heat application by permanent color change and at least one non-coated surface area, wherein the heat-sensitive coating provides indication of a heat application by a permanent difference of brightness of the at least one coated surface area, wherein the difference of brightness measured according to ISO 2469 after heating is at least 1%.

2. The wrapper according to claim 1, wherein: the difference of brightness measured according to ISO 2469 after heating is at least 2%.

3. The wrapper according to claim 1, wherein: the heat-sensitive coating provides indication of heat application after heat application by a temperature of at least 150° C.

4. The wrapper according to claim 1, wherein: the heat-sensitive coating comprises a polymer, wherein the polymer is at least one of EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, or any other film forming polymer.

5. The wrapper according to claim 1, wherein: the heat-sensitive coating provides indication of heat application after heat application of at least 3 minutes.

6. The wrapper according to claim 1, wherein: the heat-sensitive coating is provided in the at least one coated surface area in an amount of 0.5 to 20 g/m.sup.2.

7. The wrapper according to claim 1, wherein: a difference between opacity according to ISO 2471 of the at least one coated surface area and the at least one non-coated surface area of the wrapper when the wrapper is not heat-treated is less than 3%.

8. The wrapper according to claim 1, wherein: a difference between opacity according to ISO 2471 of the at least one coated surface area and the at least one non-coated surface are of the wrapper when the wrapper is heat-treated is less than 3%, after heat application by a temperature of at least 150° C.

9. An aerosol-generating article comprising the wrapper according to claim 1.

10. The aerosol-generating article according to claim 9, further comprising: an aerosol-generating substrate, wherein the aerosol-generating substrate is wrapped in the wrapper.

11. The aerosol-generating article according to claim 9, wherein: the heat-sensitive coating of the wrapper indicates heat application through color change after heat application of at least 3 minutes.

12. A method for producing an aerosol-generating article comprising a wrapper, wherein the wrapper comprises at least one coated surface area and at least one non-coated surface area, the method comprising: applying by flexography a heat-sensitive coating of the at least one coated surface area, wherein the heat-sensitive coating is configured to provide indication of a heat application by a permanent difference of brightness of the at least one coated surface area, wherein the difference of brightness measured according to ISO 2469 after heating is at least 1%.

13. The method according to claim 12, wherein: the heat-sensitive coating comprises a polymer, wherein the polymer is at least one of EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, or any other film forming polymer.

14. The method according to claim 12, further comprising: drying the heat-sensitive coating after application to the wrapper.

15. The method according to claim 12, wherein: the heat-sensitive coating is provided in the at least one coated surface area in an amount of 0.5 to 20 g/m.sup.2.

16. The wrapper according to claim 1, wherein: the difference of brightness measured according to ISO 2469 after heating is at least 3%.

17. The wrapper according to claim 1, wherein: the heat-sensitive coating provides indication of heat application after heat application by a temperature in a range from 170 to 250° C.

18. The wrapper according to claim 1, wherein: the heat-sensitive coating provides indication of heat application after heat application of between 5 and 10 minutes.

19. The wrapper according to claim 1, wherein: the heat-sensitive coating is provided in the at least one coated surface area in an amount of 4 to 10 g/m.sup.2.

20. The wrapper according to claim 1, wherein: a difference between opacity according to ISO 2471 of the at least one coated surface area and the at least one non-coated surface area of the wrapper when the wrapper is not heat-treated is less than 1%.

Description

DESCRIPTION OF THE APPENDED DRAWINGS

[0032] Further advantages, objectives and features of the present invention will be described, by way of example only, in the following description with reference to the appended figures. In the figures, like components in different embodiments can exhibit the same reference symbols.

[0033] The figures show:

[0034] FIG. 1a an image of a used (left) and a not-used (right) aerosol-generating article;

[0035] FIG. 1b an image of a possible form of the coated surface of a wrapper;

[0036] FIG. 2a a detailed image of a possible form of the coated surface on a wrapper prior heat application;

[0037] FIG. 2b the detailed image of a possible form of the coated surface on a wrapper of FIG. 2a after heat application with two circular heat applicators;

[0038] FIG. 3a-3g detailed images of possible forms of the coated surface on a wrapper after heat application with a circular heat applicator.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0039] FIG. 1a shows an image of two aerosol-generating articles 1a, 1b, each surrounded by a wrapper 10 with coated 11 and non-coated 12 surface areas according to the invention. The wrapper 10 surrounds the lateral area of a cylinder 2 (geometrically in more detail: a right circular cylinder) made of tobacco (not shown).

[0040] The wrapper 10 is partially, namely in the coated areas 11, coated with a heat sensitive coating 13. In the illustrated embodiment, this coating is applied in parallel stripes onto the wrapper 10, which is then wound around the tobacco cylinder 2. In this curved form of the wrapper 10, the coated areas 11 surround the cylinder along its circumferential direction.

[0041] On the left side of FIG. 1a a used aerosol-generating article 1a is shown. In contrast thereto, the aerosol-generating article 1b on the right side is not used. While the coating 13 is merely slightly visible prior usage of the aerosol generating article 1b (right), the local coating 13 is clearly visible after usage (left). Since the coating 13 indicates heat treatment by a permanent colour change, the stripes along the circumference of the tobacco stick 1 appear during usage. Thus, even in the case that the aerosol-generating article 1 and/or the wrapper 10 is not burnt during consumption of the tobacco and/or usage of the aerosol generating article 1, the usage is clearly indicated. This indicator prevents confusion and repeated usage of a single aerosol generating article 1. The samples illustrated in FIG. 1a are made by using commercially available aerosol-generating articles, which have been wrapped with a wrapper 10 according to an embodiment of the invention. The aerosol-generating article shown on the left in FIG. 1a has been treated by a smoking device, which simulates usage/consumption by a user.

[0042] FIG. 1b shows a further embodiment of the wrapper 10. The pattern 14 of the coated areas 11 are stripes. Thus, such a cigarette paper 10 or a very similar cigarette paper 10 could have been used for production of the aerosol-generating article 1 as shown in FIG. 1a. A base paper was coated locally with a polymer. In this embodiment, a polymer was used, which was previously used in the tobacco industry as glue for attaching overlapping ends of a cigarette paper onto each other. The application was performed by printing, in this case by flexography. The polymer was applied at an amount of about 6 g/m.sup.2 per printed area. In this embodiment about 43% (preferably between 40-50%) of the total upper surface of the (base) paper 10 was coated with the polymer.

[0043] In the embodiment of the wrapper 10 shown in FIG. 1b, the opacity of the coated 11 and the non-coated 12 area was measured. The difference between the measured opacity of these areas was very low. The opacity of the coated area 11 was determined to be 74.9% and the opacity of the non-coated area 12 was measured to be 75.6%.

[0044] FIG. 2a shows a detailed image of a possible form of the coated surface 13 on a wrapper 10 prior heat application. This sample was made based on a paper available from the company Miguel y Costas Group. In the illustrated embodiment the coating 13 is applied in a pattern 14 that forms letters on the substrate. Since a white or transparent polymer was used, the coating 13 is merely visible prior heat application. However, depending on the angle of light falling on the coating 13, it might be recognizable because of its glossiness.

[0045] FIG. 2b shows the same cut-out of a wrapper as shown in FIG. 2a. However, the cut-out shown in FIG. 2b is locally heated. For heat application, two circular heat sources (not shown) have been used. The heat-treated areas of the wrapper 10 are visible because the base paper as well as the coating 13 has changed its colour. However, the paper and the coating 13 have changed to different colours. Thus, the letters 14 become clearly visible. It should be noticed that the angle of light has been changed with respect to the illustration of FIG. 2b. At this angle, the glossiness of the coating 13 is not visible any more. Thus, the pattern 14 could not be seen or only be assumed in some non-heat-treated areas. In contrast thereto, the pattern is visible because of the different colours in the heat-treated areas.

[0046] FIG. 3a-3g illustrate the effect of different heat treatments. All FIGS. 3a-3g show detailed images of possible forms of the coated surface on a wrapper after heat application with a circular heat applicator. Also these samples were prepared based on the same paper available from the company Miguel y Costas Group. The treatment time and/or treatment temperature differs between the illustrated samples. The wrapper shown in FIGS. 3a and 3b have both been treated with a temperature of about 250° C. The wrapper shown in FIG. 3a has been treated for 60 seconds, while the wrapper shown in FIG. 3b was treated for 300 seconds. It could be seen that the pattern is not yet clearly visible after treatment of only 60 seconds (FIG. 3a) at this temperature. However, a longer treatment of 600 seconds initiates a significant colour change and the pattern 14 (letters) becomes visible.

[0047] After treatment of the wrapper 10 with a heat applicator of 300° C. the pattern will already be visible after a treatment of only 30 seconds (FIG. 3c). However, longer treatments of 60 seconds (FIG. 3d) and 300 seconds (FIG. 3e) further increase the visibility. In FIG. 3e it could be seen that due to thermal radiation, also the surrounding areas of the wrapper 10 get brownish and the circular pattern of the heat applicator is inhomogeneous.

[0048] FIGS. 3f and 3g show the wrapper 10 after its treatment with a heat applicator of 350° C. The pattern could already be seen after a treatment of only 30 seconds (FIG. 3f) as well as after 60 seconds (FIG. 3g). However, both wrappers are locally burnt.

[0049] The polymer used for the coating as shown in FIGS. 3a-3g was EVA having a viscosity of 600 mPAs at 20° C. The solid content was 48% (w/w) and the application temperature was between 15 and 25° C. No colour change was visible for this polymer after heat treatment of 200° C. or below.

[0050] The applicant reserves his right to claim all features disclosed in the application document as being an essential feature of the invention, as long as they are new, individually or in combination, in view of the prior art. Furthermore, it is noted that in the figures features are described, which can be advantageous individually. Someone skilled in the art will directly recognize that a specific feature being disclosed in a figure can be advantageous also without the adoption of further features from this figure. Furthermore, someone skilled in the art will recognize that advantages can evolve from a combination of diverse features being disclosed in one or various figures.

LIST OF REFERENCE SYMBOLS

[0051] 1 aerosol-generating article, [0052] 1a used aerosol-generating article, [0053] 1b unused aerosol-generating article, [0054] 2 cylinder [0055] 10 wrapper [0056] 11 coated surface area [0057] 12 non-coated surface area [0058] 13 coating [0059] 14 pattern