An Aerosol-Generating Article with Reduced Visual Defects

Description

The present invention is directed to an aerosol generating article comprising a filter and an aerosol generating rod with reduced visual defects.

Smoking articles such as cigarettes are consumer goods produced in large quantities. They usually comprise a tobacco rod formed by wrapping tobacco cut filler with a paper-based wrapper in a longitudinally extending substantially cylindrical rod. Beyond their primary tobacco wrapping function, paper based smoking article wrappers also often form a communication support for manufacturers and may comprise various printed designs, colors and/or markings (watermarks, embossing etc. . . . ), which may form part of branding features allowing consumers to recognize products among others. Thus, it is highly appreciated to provide an appealing appearance of the cigarette paper. Contaminations of the visible paper surface should be avoided to provide premium appearance of the cigarettes and/or the cigarette paper.

In the following the terms “smoking article” and “cigarette” are used synonymously. In the last years so-called “heat not burn” devices became more popular. In such devices a flavour source is not burnt but heated to generate an aerosol, which can be consumed by a user. The substrate from which the aerosol is generated, often comprises tobacco. The substrate is often provided in form of an exchangeable cartridge to be inserted in an aerosol generating device. Similar to conventional smoking articles as cigarettes, in these cartridges, the tobacco is often hold in place by a cigarette paper/wrapper. Some embodiments of the invention are only described for a cigarette or a cigarette paper. However, these embodiments should be considered to be applicable and disclosed also for any other aerosol generating article and/or aerosol generating article wrapper.

Many smoking articles comprise liquids. Some liquids like menthol are added as flavouring agents. The taste or properties of the aerosol can further be modified by liquids. Some of these liquids can give the aerosol a smoother taste. Examples for such liquids are fatty acids, fatty acid esters, polypropylene glycol (PPG), polypropylene glycol glyceryl ether and polyethylene glycol (PEG). Furthermore, water from different sources may be present. Especially natural products like tobacco may contain water if not sufficiently dried.

A disadvantage of liquids in the filter segment is, that even with best average amount of application, due to standard deviation of raw materials and production process, residual liquids move from the filter to an adjacent tobacco compartment and extract coloring substance from the tobacco. These coloring substances are then transported to the wrapper and cause an ugly stain of the tobacco wrapper.

In the past it has been tried to prevent such staining by coating the tobacco or the wrapper. or to make the wrapper repellent against the liquid. However, these additional coating agents often cause negative taste impact or machine trouble such as paper dust.

US 2017/332694 A1 discloses a method for manufacturing a wrapped endless rod of substantially flat continuous material.

Thus, it is an object of the invention to provide an aerosol generating article comprising a visible cigarette paper or wrapper having an appealing appearance even in case liquids are present in the aerosol generating article.

It has been found that these problems could be overcome by an aerosol-generating article comprising a filter and an aerosol generating rod; the filter comprising at least one filter segment comprising a filter media containing liquid additive and at least one filter wrapper extending from a first end to a second end of the filter for wrapping the filter media; the aerosol generating rod comprising an aerosol generating substrate and a substrate wrapper for wrapping the aerosol generating substrate, wherein the filter and the aerosol generating rod are combined together with an outer wrapper which partially overlaps with the filter wrapper and the substrate wrapper and wherein the filter wrapper and the substrate wrapper are adjacent at the first end of the filter; wherein the filter wrapper is formed as a tubular element and comprises a wrapper seam extending along a longitudinal direction of the article and the seam being formed of a sealed overlapping region of the filter wrapper, wherein the filter wrapper has no anchor adhesive with the filter media which extends up to the first end of the filter.

An aerosol generating article according to the present invention comprises a filter and an aerosol generating rod. The filter comprises at least one filter segment. The filter segment comprises a filter media, which contains a liquid additive and at least one filter wrapper. The filter wrapper can be for example a plug wrap. The terms “filter wrapper” and “plug wrap” are both used within the specification of the invention. However, all features disclosed for the special embodiment of a plug wrap should be understood to be also disclosed for any filter wrapper if not specified differently. The filter wrapper extends from a first end to a second end of the filter for wrapping the filter media.

The aerosol generating rod comprises an aerosol generating substrate and a substrate wrapper. The substrate wrapper can be for example a tobacco paper. The terms “substrate wrapper” and “tobacco paper” are both used within the specification of the invention. However, all features disclosed for the special embodiment of a tobacco paper should be understood to be also disclosed for any substrate wrapper if not specified differently. The substrate wrapper is wrapping the aerosol generating substrate.

The filter and the aerosol generating rod are combined together with an outer wrapper. The outer wrapper can be for example a tipping paper. The terms “outer wrapper” and “tipping paper” are both used within the specification of the invention. However, all features disclosed for the special embodiment of a tipping paper should be understood to be also disclosed for any outer wrapper. if not specified differently.

The outer wrapper partially overlaps with the filter wrapper and the substrate wrapper. The filter wrapper and the substrate wrapper are adjacent at the first end of the filter. The filter wrapper is formed as a tubular element and comprises a wrapper seam extending along a longitudinal direction of the article. The seam is formed of a sealed overlapping region of the filter wrapper. A further essential feature of the aerosol generating article according to the present invention is that the filter wrapper has no anchor adhesive with the filter media which extends up to the first end of the filter.

With such an aerosol generating article diffusion of liquids from the filter to the adjacent tobacco compartment is reduced or even prevented. Accordingly, no coloring substance can be extracted from the tobacco, which when transported to the wrapper, could cause an ugly stain of the tobacco wrapper. Surprisingly, diffusion of liquids could be drastically reduced if an adhesive of the filter wrapper does not extend up to the first end of the filter. It seems that a line of adhesive extending up to the first end of the filter would serve as a promoter for any diffusion of liquids to leak to the substrate wrapper and stain it. By shortening the promoter line and preferably providing at least one gap in the proximity of the first end of the filter, staining could be reduced or even prevented.

In a preferred embodiment of the aerosol generating article no anchor adhesive with the filter media is closer to the first end of the filter than 0.2 mm, preferably not closer than 0.4 mm, preferably not closer than 0.8 mm, more preferably not closer than 0.8 mm, more preferably not closer than 1 mm, most preferably not closer than 3 mm. It has been found that a distance between the first end and the anchor adhesive is sufficient to inhibit moisture transfer between the filter segment and the aerosol generating rod. However, the contact surface of the adhesive is still big enough to secure the filter wrapper.

In a preferred embodiment of the aerosol generating article, the filter wrapper is anchored to the filter media by at least one discontinuous anchor portion, preferably discontinuous anchor portions of adhesive starting at a distance from the first end of the filter in the longitudinal direction. Thus, the adhesive provides secure bonding of the wrapper ends, but does not promote diffusion of liquids till the first end of the filter from which the liquid can pass over to the aerosol generating rod.

In a preferred embodiment of the aerosol generating article, the filter wrapper is anchored to the filter media by one anchor portion which extends in both a longitudinal direction of the article and a circumferential direction of the article and wherein the length of extension if the longitudinal direction is higher than the length of extension in the circumferential direction. Alternatively or additionally, the filter medial is anchored by a plurality of anchor portions which extend in a longitudinal direction and possibly also in circumferential direction of the article and wherein the length of the extension of the plurality of anchor portions is higher than length of extension of the same in the circumferential direction. This privileged arrangement along the longitudinal direction of the article further reduces the risk of staining by limiting the diffusion of liquid towards the circumference of the article.

In a preferred embodiment of the aerosol generating article the filter wrapper is anchored to the filter media by anchor dots of adhesive starting a distance from the first end of the filter in the longitudinal direction. Preferably the anchor dots of adhesive are arranged along a line which extends along the longitudinal direction of the filter from its first end to its opposite second end. It has been found that dots of an adhesive could be applied easily by known devices. Furthermore, less adhesive is consumed when provided as dots instead of a continuous line. Thus, the anchor portion could be generated at low costs. A further advantage of dots is that they could be applied to be separated from each other. Thus, diffusion of liquids is not only prevented in the region next to the first end of the filter but even remote from its first end, every gap between adjacent dots can be considered as barrier, which hinders or at least slow down diffusion of liquids along the longitudinal direction of the filter towards its first end.

In a preferred embodiment of the aerosol generating article the filter wrapper is anchored to the filter media by a non-straight but continuous layer of anchor adhesive starting at a distance from the first end of the filter wrapper in the longitudinal direction. The curved layout results in an extended path compared to a straight line. Thus, diffusion of liquids along the longitudinal direction of the filter towards its first end is slowed down. Furthermore, it has been found that tight curves result in local deceleration of the diffusion along the curved path. This could be explained by locally increased moisture in the area of the curves. This effect also slows down the diffusion of liquids along the longitudinal direction of the filter towards its first end.

In a preferred embodiment of the aerosol generating article the filter wrapper is anchored to the filter media by a spirally shaped or multiple-ring shaped layer of anchor adhesive. These both geometries have been found advantageous, since they also provide the effect mentioned above. The spirally shaped geometry of the anchor adhesive further extends the length of the line of the anchor adhesive. Thus, the relative speed of diffusion along the longitudinal direction of the filter towards its first end is reduced. The multiple-ring shaped geometry of the anchor adhesive provides circles along which the diffusion is promoted.

However, the moisture is caught inside the rings or by the annulus formed by the anchor adhesive. This also results in decelerated diffusion of the diffusion of the liquid along the longitudinal direction of the filter towards its first end.

In a preferred embodiment of the aerosol generating article the liquid additive in filter media contains an oily and/or flavour substance. These liquids can be used to change the taste or properties of the aerosol. For example, some liquids can give the aerosol a smoother taste.

In a preferred embodiment of the aerosol generating article the liquid additive in filter media is in an amount (per filter) of at least 1 mg, preferably between 1 and 50 mg, more preferably between 10 and 20 mg. these amounts have been found to be suitable to improve the taste or properties of the aerosol when passing through the filter.

In a preferred embodiment of the aerosol generating article the liquid additive is selected from a group comprising an alcohol, a fatty acid, a fatty acid ester, a polyether polymer, an essential oil, and combinations thereof. More preferably a liquid is selected from a group comprising polypropylene glycol (PPG), polypropylene glycol glyceryl ether, polybutylene glycol, diglycerin, sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polyethylene glycol, caprylyl glycol and combinations thereof. At least some of these substances are suitable to reduce the amount of phenols from the aerosol, which results in a smoother taste for the user.

In a preferred embodiment of the aerosol generating article the filter media comprises paper and/or other natural cellulose fibre. It has been found that filter media comprising paper and/or other natural cellulose fibre are especially suitable since the diffusion of moisture through these media is slow. Accordingly, if diffusion along the adhesive to the first end of the filter segment is not possible or very slow because the anchor portions of adhesive starting at a distance from the first end, the entire diffusion of liquids from the filter segment to the aerosol generating substrate will not be possible or very slow.

In a preferred embodiment of the aerosol generating article the filter wrapper is free of hydrophobic or oleophobic coating. Since diffusion of liquids through the filter material can usually be controlled, the wrapper has been considered to be important to control moisture diffusion. Thus, attempts have been made to reduce diffusion of liquids from the filter segment to the aerosol generating substrate by applying a hydrophobic or oleophobic coating to the wrapper. However, these coatings provide disadvantages, since they can have negative effects on the taste of the aerosol. The present invention offers a different way to prevent or slow down diffusion of liquid. It is possible and preferred to provide the filter wrapper without a hydrophobic or oleophobic coating. Thus the taste of the aerosol is not negatively affected by the coating of the wrapper.

In a preferred embodiment of the aerosol generating article is a combustible article or a heat-not-burn article for being heated in an electrically aerosol generating device. Thus, the aerosol generating article can be preferably provided as traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco or as an aerosol substrate for a so-called “heat-not-burn” device. Devices of this type generate an aerosol and/or vapor by heating a solid aerosol substrate, typically comprising tobacco, to a temperature typically in the range 200° C. to 350° C.

Experiments have been performed to evaluate the advantages of aerosol generating articles according to the present invention (line 2) with respect to aerosol generating articles according to the prior art (line 1). The aerosol generating articles according to the prior art comprise a filter with an anchor glue extending up to the very first end of the filter next to the aerosol generating substrate. In contrast thereto the anchor glue in the aerosol generating articles according to the present invention (line 2) does not extend up to the very first end of the filter next to the aerosol generating substrate.

As shown in Table 1, when stored 200 aerosol generating articles according to the prior art at “normal conditions” (22° C. and 60% relative humidity (RH)), staining of the tipping paper (TP) was observed at 14 rods which is equal to 7% of all rods. In contrast thereto staining was only observed for a single aerosol generating article according to the present invention (equal to 0.5%), when stored at the same conditions. Staining of the cigarette paper (CP) was not observed for any aerosol generating article when stored at these conditions.

When stored at so-called “climate conditions” (35° C. and 40% relative humidity (RH)), staining of the tipping paper (TP) was observed at 18 rods of the aerosol generating articles according to the prior art. This corresponds to 9% of all rods. In contrast thereto staining was only observed for 6 rods of aerosol generating articles according to the present invention (equal to 3%), when stored at the same conditions. Staining of the cigarette paper (CP) was not observed for any aerosol generating article when stored at these conditions.

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 figure. In the figure, like components in different embodiments can exhibit the same reference symbols.

The figures show:

FIG. 1a-1d a schematic illustration of different embodiments of wrapper seam arrangements in an overlapping region of the filter wrapper of an aerosol-generating article; and

FIG. 2 photographs of different staining of the tipping paper.

FIG. 1a shows a schematic illustration of a wrapper seam arrangement in an overlapping region of the filter wrapper of an aerosol-generating article as it is known from the prior art. The aerosol generating article 1 comprises a filter 2 and an aerosol generating rod 6. The filter 2 and the aerosol generating rod 6 are arranged next to each other along the longitudinal direction of the aerosol generating article 1. They are held together by an outer wrapper (not shown) which partially overlaps with a filter wrapper and the substrate wrapper (not shown). The filter wrapper surrounds the filter material. The ends of the filter wrapper are attached to each other by a seam 4 extending along a longitudinal direction of the article. The seam 4 is formed by a sealed overlapping region of the filter wrapper. The seam of the filter wrapper extends up to the first end of the filter 2, adjacent to the aerosol generating rod 6.

By diffusion a liquid 3 can migrate along the seam 4 from any position in the filter up to the first end of the filter 2, adjacent to the aerosol generating rod 6.

FIG. 1b shows a schematic illustration of a single drop of liquid 3 on a surface of the filter material 2. The size of the drop 3 is limited since migration and diffusion through the filter material 2 is limited. The liquid 3 does not migrate filter up to the first end of the filter 2, adjacent to the aerosol generating rod 6 if no seam is present.

FIG. 1c shows a schematic illustration of a wrapper seam arrangement in an overlapping region of the filter wrapper of an embodiment of the aerosol-generating article according to the present invention. Similar to the aerosol generating article 1 as shown in FIG. 1a, the aerosol generating article 1 comprises a filter 2 and an aerosol generating rod 6. The filter 2 and the aerosol generating rod 6 are arranged next to each other along the longitudinal direction of the aerosol generating article 1. They are held together by an outer wrapper (not shown) which partially overlaps with a filter wrapper and the substrate wrapper (not shown). The filter wrapper surrounds the filter material 2. The ends of the filter wrapper are attached to each other by a seam 4. The seam is formed by an anchor adhesive arranged in overlapping circles (or ovals). However, the seam does not extend up to the first end of the filter 2, adjacent to the aerosol generating rod 6.

Due to the geometry of the seam and the different concentration of the anchor adhesive in different regions of the filter wrapper, the migration and diffusion of the liquid is limited. The liquid tends to be concentrated in regions of high anchor adhesive concentration, whereas in regions with low anchor adhesive concentration or absence of the anchor adhesive, the concentration of the liquid 3 is low.

Since the seam and/or the anchor adhesive does not extend up to the first end of the filter 2, adjacent to the aerosol generating rod 6, the concentration of the liquid in this region is very low and no liquid can migrate from the filter to the aerosol generating rod 6. Accordingly, the liquid is not able to extract coloring substances from the aerosol generating substrate which—upon migration to the surface of the aerosol generating rod 6 or the surrounding tipping pater—could cause staining of the paper.

FIG. 1d shows a schematic illustration of a wrapper seam arrangement in an overlapping region of the filter wrapper of a further embodiment of the aerosol-generating article according to the present invention. Similar to the aerosol generating article 1 as shown in FIG. 1c, the ends of the filter wrapper are attached to each other by a seam 4. However, the seam is formed by an anchor adhesive arranged as several dots distant with respect to each other. None of these dots extend up to the first end of the filter 2, adjacent to the aerosol generating rod 6.

A liquid 3 present in the filter material 2 will remain in high concentration in a region surrounding a dot of the anchor adhesive. Depending on the spacing between two neighboring dots, migration of the liquid from one dot to the next dot is very limited.

Since no dots of the anchor adhesive are arranged in a region next to the first end of the filter 2, adjacent to the aerosol generating rod 6, the concentration of the liquid in this region is very low and no liquid can migrate from the filter to the aerosol generating rod 6. As described above with respect to the arrangement shown in FIG. 1c, the liquid is not able to come in contact to the aerosol generating substrate for extracting coloring substances which could cause staining of the paper.

FIG. 2 shows photographs of different staining of the tipping paper. In the left photograph, staining is very prominent and extends to the cigarette paper (CP). In the photograph shown on the right, staining is only present on the tipping paper (TP). It has been found that staining mostly occurs in rings.

LIST OF REFERENCE SYMBOLS

• • 1 aerosol-generating article,
  • 2 filter, filter material,
  • 3 liquid, drop, polypropylene glycol,
  • 4 seam, anchor glue, ring, circle, dot,
  • 6 aerosol-generating material, aerosol-generating rod.