Field of the Invention

The present invention relates to a tobacco pouch which can be used to store tobacco for long periods of time.

Background to the Invention

Tobacco for roll-your-own or make-your-own smoking items is typically stored in a sealed pouch made from a metallised or non-metallised material. An example of such a pouch comprises a closure strip that seals the tobacco content for transport and which can be broken by a user to access the contents when necessary.

One problem associated with using sealed pouches (particularly pouches made from a metallised material) to store tobacco is that when the pouches of tobacco are stored at higher temperatures, for example in warm climates, the tobacco tends to generate a bad odour over extended periods of time (e.g., over a few months). Therefore, when a consumer opens a pouch which has been stored under such conditions, the bad odour reveals itself and this results in an unpleasant smoking experience. Therefore, there is a need to provide a pouch (particularly a pouch made from a metallised material) for storing tobacco such that, even if it is stored at higher temperatures, the tobacco does not develop a bad odour. Of course, it is also desirable for the production of such a modified pouch to be simple, reliable and cost-effective. Summary of the Invention

A first aspect of the invention provides a method of producing a pouch containing a fibrous material, wherein the pouch comprises a pocket having a mouth for providing access to the interior of the pocket; and a closure strip extending along the mouth, and wherein the method comprises the steps of: providing said pouch (which can be, for example, formed from a sheet of material); filling the pocket with a fibrous material via the mouth; and sealing the closure strip such that at least one channel is retained to allow for fluid communication between the interior and exterior of the pocket. Preferably, the closure strip is not resealable.

A second aspect of the invention provides pouch for containing a fibrous material, obtainable by the above-mentioned method.

A third aspect of the invention provides a heater bar for use in the method according to the first aspect.

Description of the Drawings

Figure 1 illustrates a pouch according to the prior art wherein the closure strip is completely sealed all the way across its opening such that fluid cannot exchange between the interior and exterior of the pouch.

Figure 2 illustrates a pouch according to the invention comprising a channel in the closure strip which allows for fluid communication between the interior and exterior of the pouch.

Figure 3 illustrates a pouch according to the invention comprising two channels in the closure strip.

Figure 4 illustrates a cross-section of a pouch according to the invention. Figure 5 illustrates a modified heater bar which is used in the method according to the invention to seal the pouches.

Figures 6 to 1 1 illustrate several comparisons between the pouch according to the invention and a known tobacco pouch.

Detailed Description of the Invention

Figure 1 shows a known tobacco metallised pouch 1 with a seal 4 that extends across the mouth 3. The pouch 1 has a flap 6 that a user can fold over the mouth 3. It is believed that in a completely sealed pouch with no channels, such as the pouch 1 shown in Figure 1 , oxygen content decreases and carbon dioxide content increases on storage, which in turn gives rise to the tobacco generating a bad odour. The present inventors have found that this is attributed to the fact that tobacco pouches are typically made from material having low gas permeability. The present inventors have found that this effect is increased in warmer climates (i.e. above 27 °C) where the pouch is exposed to higher temperatures for extended periods. Therefore, the present inventors have found that by controlling the oxygen and carbon dioxide content within the pouch, the tobacco contained therein remains fresher for longer such that it can be stored over extended periods of time.

Figures 2 to 4 depict a pouch 1 for containing tobacco, having a closure strip 4 across the mouth 3 of the pouch wherein the mouth 3 is used to provide access to the pocket 2 where the tobacco is contained. The closure strip 4 is sealed such that a channel 5 is retained. The channel 5 allows for fluid communication between the interior and exterior of the pocket 2 which contains the tobacco. In Figure 3, an alternative embodiment of the present invention is depicted wherein the closure strip 4 comprises two channels 5.

In Figures 2 and 3, the channels 5 are shown to be positioned towards one end of the closure strip 4. However, the channels 5 can be positioned anywhere along the closure strip 4. Preferably, the closure strip 4 comprises at least one channel 5, although the closure strip 4 may comprise at least two channels 5 or at least three or five channels 5. Preferably, where the closure strip 4 contains only one channel 5, the channel 5 is positioned towards one end of the closure strip 4.

The channel 5 can be from 1 .0 % to 12.5 % of the length of the closure strip 4, preferably from 3.0 % to 9.0 %, most preferably from 3.5 % to 7.0 %. When the closure strip 4 comprises at least two (or more) channels, the total channel opening is from 1 .0 % to 12.5 % of the length of the closure strip 4, preferably from 3.0 % to 9.0 %, most preferably from 3.5 % to 7.0 %. The channel 5 can be from 2 mm to 10 mm of the closure strip 4.

Preferably, where the closure strip 4 comprises only one channel 5, the channel is from 3 mm to 7 mm, and more preferably it is 5 mm. When the closure strip 4 comprises at least two (or more) channels, the total channel opening is from 3 mm to 7 mm, and preferably 5 mm.

Preferably, the length of the closure strip 4 is from 65 mm to 145 mm. Most preferably, the length of the closure strip is from 70 mm to 80 mm, from 1 10 mm to 120 mm or from 130 mm to 140 mm. As shown in Figure 4, the pouch 1 may further comprise a flap 6 which extends from the mouth 3 which is capable of folding over the pocket 2. When the pouch 1 is closed, the flap 6 is turned over against the pocket 2 of the pouch 1 and may be detachably connected with an adhesive.

The pouch can be formed from a sheet or film of a thermoplastic material such as a polyolefin, e.g. polyethylene. However, the pouch is preferably made of a metallised material comprising oriented polypropylene (OPP), polyethylene terephthalate (PET), metallised polyethylene terephthalate (MPET), polyethylene (PE) or any combination thereof. Preferably, the pouch is made of a material comprising OPP, MPET and PE or PET, MPET and PE. The advantage associated with using a metallised material over a non-metallised material is that the tobacco is kept moist for longer periods of time. The pouch material typically has an oxygen transmission rate (OTR) in the range of from 1 to 800 cm ³ /m ² /24h/1 atm, preferably from 1 to 400 cm ³ /m ² /24h/1 atm, most preferably from 1 to 200 cm ³ /m ² /24h/1 atm. OTR values can be calculated according to the standard method ASTM D3985. In addition, the pouch material typically has a water vapour transmission rate (WVTR) of from 0.1 to 4 g/m ² /day, preferably from 0.2 to 3.5 g/m ² /day. WVTR values can be calculated according to the standard method ASTM F1249.

The method according to the present invention can comprise forming the pouch from a sheet of material, wherein the material is as described above. The pouch is conventionally formed from a rectangular sheet of material which is folded over itself and welded together at the edges to form a pocket where the tobacco is to be kept. A portion of the rectangular sheet extending beyond the mouth of the pocket forms a flap capable of folding over the pocket. A strip of heat activatable glue is then placed along the mouth of the pocket thereby forming a strip capable of being closed.

Once the pouch has been formed from the sheet of material, the pocket of the pouch is filled with tobacco via the mouth. After filling of the pouch with tobacco, the closure strip is then sealed such that at least one channel is retained to allow for fluid communication between the interior and exterior of the pocket of the pouch; for example, to allow for the exchange of oxygen and carbon dioxide between the interior and exterior of the pocket of the pouch. Preferably, the closure strip comprises heat activatable glue such that when the closure strip is heated, the glue is activated thereby providing a seal. The closure strip comprising the heat activatable glue can be heated using a metal heater bar 8 as shown in Figure 5 which, when pressed against the closure strip, activates the glue. In a preferred embodiment, the closure strip is not resealable.

It can be seen from Figure 5 that the heater bar 8 comprises a recess 9 such that when pressed against the closure strip, a portion of the closure strip comprising the heat activatable glue is not heated. This portion which is not (or less) heated gives rise to the channel allowing for fluid communication between the interior and exterior of the pouch. For example, if a channel of 5 mm of the closure strip is required, the recess will be 5 mm in width. In an alternative embodiment (not depicted), the heater bar may comprise more than one recess if more than one channel is required.

In an alternative and preferred embodiment, instead of having the recess on the heater bar, a recess is located along the closure strip which may comprise the heat activatable glue. In this alternative embodiment, the term "recess" is to be understood as a portion of the closure strip deprived from heat activatable glue. Thus in this embodiment, instead of modifying the heater bar so as not to completely seal the pouch, the modification is made to the closure strip; i.e., where the heat activatable glue is deposited along the closure strip so that at least one air channel can be formed. Thus, instead of modifying the machine used to close the pouches, it is possible to use non sealed pouches with a closure strip where the heat activatable glue is not deposited continuously along the closure strip so that at least one air channel can be formed, i.e., the channel is formed at the position where no adhesive is present along the closure. Once the closure strip is sealed, it can be opened by a consumer by applying a force to either side of the pocket. However, when the seal has been broken, it cannot be resealed. Examples

Tobacco Moisture Content

The moisture content of tobacco in a metallised pouch of the present invention (as depicted in Figure 2) having a channel of 5 mm in the closure strip (1 15 mm long) was analysed over a period of six months. In addition, and by way of comparison, the moisture content of tobacco in a completely sealed metallised pouch was analysed over the same period. Tobacco moisture content was measured at 22°C/60%RH and 27°C/47%FtH using a Borgwaldt F21 instrument.

Figures 6 and 7 show that the moisture content of the tobacco in the sealed metallised pouch and the pouch according to the invention remains between the moisture tolerance levels for tobacco under both conditions.

Oxygen Content

The oxygen content within a metallised pouch of the present invention (as depicted in Figure 2) containing tobacco and having a channel of 5 mm in the closure strip was analysed over a period of six months. In addition, and by way of comparison, the oxygen content within a completely sealed metallised pouch containing tobacco was analysed over the same period. The oxygen content was measured at 22°C/60%FtH and 27°C/47%FtH using a PBI Dansensor Checkpoint Handled Gas Analyser. It can be seen, from Figures 8 and 9, that oxygen content decreases more rapidly at 27°C/47%FtH than at 22°C/60%FtH when the pouch is completely sealed. However, it can be seen that the oxygen content within a pouch according to the invention remains consistent over the six-month period. Carbon Dioxide Content

The carbon dioxide content within a metallised pouch of the present invention (as depicted in Figure 2) containing tobacco and having a channel of 5 mm in the closure strip was analysed over a period of six months. In addition, and by way of comparison, the carbon dioxide content within a completely sealed metallised pouch containing tobacco was analysed over the same period. The carbon dioxide content was measured at 22°C/60%RH and 27°C/47%RH using a PBI Dansensor Checkpoint Handled Gas Analyser.

It can be seen from Figures 10 and 1 1 that the carbon dioxide content steadily increases over the six-month period. However, it can also be seen that the carbon dioxide content within a pouch according to the invention remains constant and low throughout the six-month period.

Summary of results

It has been found that in warmer conditions, tobacco stored for long periods of time within a pouch according to the invention does not exhibit a bad aroma in comparison to tobacco stored over the same period of time within a completely sealed pouch, where the tobacco generates an unacceptable "rotten fruit" aroma.

It is believed that the unacceptable aroma is a direct result of a lack of oxygen and generation of carbon dioxide within the pouch containing tobacco. As can be seen from Figures 8 to 1 1 , the pouch of the invention maintains an ideal aerobic environment for the tobacco and therefore the unacceptable aroma does not arise. In contrast, in the completely sealed pouch, the oxygen content in the pouch decreases rapidly to zero and the carbon dioxide content increases steadily (these trends are enhanced at higher temperatures and lower humidity) resulting in an anaerobic environment and therefore generation of the aforementioned unacceptable aroma.