The present invention relates to packaging having a structure which enables its contents to be kept moist, and particularly, but not exclusively to a container for use with tobacco products.

The tobacco in products such as cigarettes, cigars and loose tobacco for pipe smoking or roll-your-own cigarettes is prone to drying out both during the pre-use storage period and particularly after the product packaging has been opened. This is undesirable, since tobacco becomes less palatable as it dries.

Expensive cigars are generally stored in specially designed humidors specifically to address this problem by keeping the cigars at a desired level of humidity to prevent drying. A more rudimentary approach is often used by consumers of loose tobacco; a piece of apple of potato peel placed in the tobacco pouch or tin can help to keep the tobacco moist or can re-moisten tobacco that has become too dry. However, this method may not be considered hygienic, and may taint the tobacco with unwanted scents or flavours.

Various humidification devices and moisture dispensers have therefore been proposed for use with tobacco products, in particular for use in tobacco pouches and tins and cigarette packs. Typically, the devices comprise a source of moisture that can emit water vapour which is surrounded by a permeable enclosure such as a housing, casing, layer or pouch which keeps the moisture source separate from the tobacco but allows the water vapour to be transmitted to the tobacco. The moisture source is often some form of water-absorbent medium such as cotton wool, blotting paper, sponge, florists' foam, or polyacrylamide gel or crystals, which is soaked with water or salt solution. The permeable enclosure may be rigid or flexible, and may be made permeable by the provision of perforations or apertures therein, or may be an inherently permeable membrane material.

As these humidification devices and moisture dispensers are designed as objects to be inserted into a tobacco container, they may become easily lost in everyday use. In addition, the objects are generally in direct contact with the tobacco itself, which may hinder the distribution of moisture to all parts of the tobacco, and cause inconvenience to a consumer needing to separate the object from the tobacco when taking it from the container.

A solution to this problem has been to incorporate a means of providing humidification into the tobacco packaging itself. However, this can lead to undesirable packaging shapes and sizes. In addition, such objects may have a relatively localised humidifying effect, with strong humidification obtained close to the moisture source, but a weaker effect observed further away from the source.

United Kingdom Patent specification GB 1,369,992 discloses tobacco packaging having a moisture-containing layer enclosed between a polypropylene outer film and a polystyrene inner film, so that the moisture can humidify the tobacco through the polystyrene film.

German Utility Model DE 8,715,315 discloses a structure in which an attachment can be fixed to an inner layer of a packet having a fabric-covered moisture layer, the moisture transferable to tobacco in the packet through perforations in the fabric.

An aim of the present invention is to provide a container for tobacco products having a structure which permits case of use, and which provides effective humidification to its contents. It will be appreciated, however, that the container of the present invention is equally useful for storming non-tobacco products where humidification is required.

According to an aspect of the present invention, there is provided packaging having a laminate structure comprising first and second polymeric layers and a moisture-containing layer interposed between the polymeric layers, the moisture-containing layer arranged to transfer moisture to the interior of a container formed by the packaging.

A laminate design can be light and flexibly and enables the packaging to be rolled or folded and to be carried and stored easily as a result. In addition, the laminate structure means that moisture can be distributed across a layer of the packaging rather than being localised, so that the shape of the packaging is more convenient for a consumer, with no associated loss in humidifying effect. The laminate design can also be reinforced with resilient material for use in packages where it is important to protect the shape of its contents, such as cigarettes.

A portion of the first polymeric layer may be removable so as to expose a corresponding portion of the moisture-containing layer to the interior of the container.

The removable portions may have the form of a tear-off strip, which is defined by a weakened perimeter in the first layer, and is easily removed so as to enable moisture to migrate from the moisture-containing layer to the contents of the container.

The packaging may comprise a plurality of tear-off strips, and the moisture-containing layer may contain a plurality of partitions corresponding to the tear-off strips in the first layer. This enables finer control of the humidifying effect provided by the packaging as moisture can be controllably exposed to the contents of the container throughout the lifetime of the packaging contents.

Each of the tear-off strips may have a different size, so that for example a large strip can be removed when the container contains a large amount of product, and smaller strips are successively removed as the product is used up.

The packaging may further comprise a one-way semi-permeable layer between the first polymeric layer and the moisture-containing layer to prevent migration of moisture from the interior of the container to the moisture-containing layer but to enable migration of moisture from the moisture-containing layer to the interior of the container. This avoids contamination of the moisture in the moisture-containing layer through elements associated with the product contained in the container, without reducing the humidifying effect.

The first polymeric layer may itself be a one-way semi-permeable layer or a porous layer, so that the moisture-containing layer can maintain the container and its contents at a desired moisture level without any consumer interaction, such as removal of portions of the laminate material.

The first and/or second polymeric layers may be formed from a material selected from: polyethylene, polypropylene, polystyrene, polyethylene terephthalate and polyactic acid.

The moisture-containing layer may comprise a moisture-containing element impregnated with water. The moisture-containing element may be formed from a material selected from: paper, micro-crystalline cellulose, ispaghula husk, saturated silica gel, rice, starch gels, pectins, natural sponge, synthetic sponge, clay materials, gelatine, agar, cellulosic gum, and alginates. If the moisture-containing element is paper, it may have a matrix form, comprising polyacrylamide crystals.

The first and second polymeric layers may be waterproof to prevent contamination of the product in the container from the environment.

The packaging may contain a humidity indicator, to provide guidance to a consumer as to when portions of the first layer should be removed to expose the moisture to the interior of the container.

The packaging may be used with tobacco products or smoking articles. As used herein, the term "smoking article" includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products. The term "tobacco product" refers to any item made in, or sold by the tobacco industry, typically including a) cigarettes, cigarillos, cigars, tobacco for pipes or for roll-your-own cigarettes, (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes); and b) non-smoking products incorporating tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes such as snuff, snus, hard tobacco, and heat-not-burn products. This list is not intended to be exclusive, but merely illustrates a range of products which are made and sold in the tobacco industry.

Embodiments of the present invention will now be described by way of example only, with reference to the following drawings, of which:

• Figure 1 shows an example of a tobacco pouch;
• Figure 2 shows the laminate structure of the packaging used to form the tobacco pouch of Figure 1, according to an embodiment of the invention;
• Figure 3 shows an example of a tear-off strip in the first polyethylene layer of the laminate structure of Figure 2;
• Figure 4 shows the portion of the first polyethylene layer of Figure 3 with the tear-off strip removed;
• Figure 5 shows the position of the tear-off strip of Figure 3 in the interior of a tobacco pouch according to the present invention;
• Figure 6 shows a further embodiment of the interior of a tobacco pouch according to the present invention;
• Figure 7 shows a further embodiment of the laminate structure of a tobacco pouch according to the present invention;
• Figure 8 shows a further embodiment of the interior of a tobacco pouch according to the present invention;
• Figure 9 shows a hinged-lid packet according to a further embodiment of the invention; and
• Figure 10 shows a hinged-lid packet according to a further embodiment of the invention.

Figure 1 shows an example of a tobacco pouch 1. The pouch 1 has a containing portion 2 in which tobacco 3 is stored, and has a flap 4 which can be used to close the pouch 1. The flap 4 contains an adhesive portion 5 which enables the pouch 1 to be resealed after use, although it will be appreciated that various mechanisms may be used in order to close the pouch 1 after use, all of which are applicable to the present invention.

The pouch 1 is flexible which enables it to be folded or rolled, and is substantially waterproof.

Figure 2 shows a cross section, taken along the line XY through the rear wall of the pouch 1 shown in Figure 1, which illustrates the structure of the packaging material which is used according to an embodiment of the present invention. The pouch wall has a laminate structure which comprises first and second polymeric layers 6, 8, and a moisture-containing layer 7 interposed between the first and second layers 6, 8.

In this embodiment, the polymeric materials are polyethylene. The first polyethylene layer 6 forms the interior of the pouch 1, and the second polyethylene layer 8 forms the exterior of the pouch 1. The polyethylene layers 6, 8 are waterproof, so that all of the moisture in the moisture-containing layer 7 is confined to the laminate structure.

The moisture-containing layer 7 is made from paper, which has been impregnated with water during the manufacture of the pouch. In this embodiment, the paper layer has been impregnated with 10g of water, and the pouch is intended to hold approximately 50g of tobacco.

Figure 3 shows a plan view of an area 9 of the first polyethylene layer 6 of the pouch 1, which forms the pouch's interior. A portion of the layer comprises a tear-off strip 10, which is defined by a weakened perimeter 11 (through, for example, small perforations), and a tab portion 12 enabling the tear-off strip 10 to be removed from the layer 6 when pulled.

Figure 4 shows a plan view of the same area 9 of the first polyethylene layer 6 of the pouch 1 as shown in Figure 3, with the tear-off strip 10 removed. The moisture-containing layer 7 is exposed where the first polyethylene layer 6 has been removed.

When a portion of the first polyethylene layer 6 has been removed, a corresponding portion of the moisture-containing layer 7 is exposed to the interior of the pouch 1. The moisture in the moisture-containing layer 7 is then free to migrate to the interior of the pouch 1, where it can hydrate the tobacco 3 stored in the containing portion 2.

Figure 5 shows an example of the position of the tear-off strip 10 in the interior of the pouch 1 in this embodiment, although it will be appreciated that the invention is not limited to this arrangement, and the strip 10 can be arranged in any preferred location or orientation, horizontally or vertically or at an angle with respect to a dimension of the pouch 1. The strip should preferably be positioned so that it is not too close the opening of the pouch 1, so as to avoid unnecessary loss of moisture to the environment when the flap 4 is open. A number of differently shaped strips can also be used, such as rectangular or circular, or a more complex pattern. The tab portion 12 should be easy for a consumer to access, and should be positioned so that if the pouch 1 is rolled or folded after use, the migration of water from the exposed portion of the moisture-containing layer 7 to the tobacco 3 is not unnecessarily hindered, so that a strong humidifying effect can be achieved.

The moisture-containing layer 7 can be formed from any material which is capable of storing, holding or otherwise providing a quantity or reservoir of moisturising liquid such as water, and releasing the water as a vapour, preferably at room temperature. Water is a particularly convenient substance for the moisturising of tobacco, but other substances with suitable properties for the necessary storage and vapour release can be used. The paper layer described above preferably has the form of a matrix, in which crystals or granules of polyacrylamide can be incorporated.

A further example of a material suitable for the moisture-releasing layer 7 is one or more alginates. These materials are linear copolymers produced by various brown algae including seaweed (such as giant kelp) and bacteria (such as Azotobacter species), which are insoluble in water but absorb water very quickly. Alginates are fully biocompatible and are used in consumable products, so are a particularly attractive option for tobacco storage.

Further examples of suitable materials are micro-crystalline cellulose, ispaghula husk, saturated silica gel, rice, starch gels, pectins, natural sponge, synthetic sponge, clay materials such as sepolite and bentonite, gelatine, agar and modified cellulosic gum. Combinations of these materials may also be used. A gel may be configured to release moisture at a controlled rate, and may also be adapted to release heat as well as moisture.

However, the invention is not limited to these particular examples of materials for the moisture-containing layer. Any material which has the necessary properties to allow it to absorb an adequate amount of liquid such as water and then release the liquid as vapour by evaporation can be used.

A selection of a moisture-containing material can be made which is appropriate to the particular application of the pouch 1. Where the pouch 1 is intended to be folded or rolled, structural flexibility may be an important factor, and so the more rigid materials can be avoided. Conversely, where structural rigidity is preferred, for storage of cigarettes or pre-rolled tobacco for example, a more resilient material can be selected for the laminate structure.

If water is used to provide the moisture, it need not be plain water. An aqueous salt solution may be used instead which can give control over the evaporation by determining the humidity of the surrounding environment below which the water vapour will be released. Other non-volatile liquid ingredients such as glycerol (glycerine) or propylene glycol may alternatively be used; these also control evaporation of the water.

Additionally, or alternatively, the moisture-releasing element may also contain one or more water-soluble additives that can be carried through the one-way membrane by the water vapour and hence delivered to the tobacco. These may include flavourants and fragrances. For example, a moisture-releasing element containing menthol can be used to impart a menthol flavour and smell to the tobacco. Vanilla, coffee and other flavours may be similarly provided. In this way, the consumer has a mechanism for flavouring a tobacco product with a flavour of their choice.

The tear-off strip 10 in the first polyethylene layer 6 is designed so that it has a shape and position in the tobacco pouch 1 such that the humidifying effects of the moisture-containing layer can be optimised. For example, in Figure 5, it is shown positioned so that it is not in direct contact with the tobacco 3, so that a good distribution of the humidifying effect can be achieved.

One of the main factors which must be taken into consideration for optimising the humidifying effect is the time period over which the effect is to be observed. Preferably this is designed to coincide with the period of use of the tobacco product 3 in the pouch 1, so that tobacco 3 can be kept moist until all of it has been used up. However, excessive amounts of moisture in the laminate structure should be avoided if the weight of the pouch 1 is to be reduced and flexibility increased.

For the embodiment described above, 10g of water in the moisture-containing layer 7 is sufficient to hydrate approximately 50g of tobacco over a period of use by a moderate smoker, via an opening in the first polyethylene layer 6 of approximately 2.5cm.

The length of time of the humidifying effect can be controlled by a number of factors. Firstly, the amount of water incorporated into the laminate structure can be controlled during the manufacture of the tobacco pouch 1 so as to correspond to a particular pouch size, or expected rate of drying of the products. Secondly, the amount of the moisture-containing layer 7 which is exposed to the interior of the pouch can be controlled in a number of ways, as described below.

In a further embodiment of the present invention, shown in Figure 6, a plurality of tear-off strips 13a, 13b, 13c is incorporated into the first polyethylene layer 6 of the pouch 1. Each strip can be individually peeled from the laminate structure in the same way as described above, and so a consumer can peel off each strip at convenient times. For example, a strip can be torn off every two days in order to obtain a renewed humidifying effect in the pouch 1.

Each individual tear-off strip 13a, 13b, 13c can be of a different size (not shown). As an example, a large tear-off strip can be arranged as the first strip to be removed in the lifetime of the tobacco product 3, when there is the most tobacco contained within the pouch 1. Successively smaller strips can then be torn off over time, to provide an additional, but smaller, moisture effect as the amount of tobacco remaining 3 in the pouch 1 reduces.

As an alternative to tear-off strips, perforations can be made in the first polyethylene layer at predetermined locations and covered with removable cover portions adhered to the polymeric material around the perforation. These cover portions could then be removed in the same way as the tear-off strips described above, in order to expose the moisture-containing layer to the tobacco product. As a further alternative to tear-off strips, re-sealable strips can be used which could be re-applied to the first polyethylene layer as desired in order to seal the moisture-containing layer. This would enable a consumer to have more control of the humidifying effect provided by the moisture-retaining layer. For example, as tobacco products are used, it may no longer be necessary to provide the same level of humidification as that provided when the pouch was full.

In a further embodiment, shown in Figure 7, the laminate structure of the pouch comprises a further layer 14 between the moisture-containing layer 7 and the first polyethylene layer 6. This further layer is a one-way semi-permeable membrane 14 which enables water vapour to migrate from the moisture-containing layer 7 to the tobacco products 3 in the pouch 1, but prevents the water vapour migrating in the reverse direction. This is advantageous in applications where it is desirable to keep the moisture-containing layer 7 free from contaminants which could be picked up from the environment and later released to the tobacco 3.

An advantage of using a semi-permeable layer of this form is that it prevents the moisture-containing layer 7 from re-absorbing moisture from the tobacco product 3 after most of the water in the paper layer has already been released (for example after removal of a tear-off strip), which could otherwise dry out the tobacco 3. The inability of the moisture-containing layer 7 to re-absorb water in this embodiment means that it cannot take up the flavor of the tobacco, which could otherwise be undesirable. In addition, the membrane 14 prevents the paper in the moisture-containing layer 7 taking up any form of brown staining.

The one-way semi-permeable membrane 14 may comprise a reverse osmosis membrane, such as a synthetic dialysis membrane or other food-grade pharmaceutical membrane. Suitable membrane materials include cellulose acetate, polysulphones or polyvinylfluoride. However, any material with the desired property of one-way transmission of vapour from the moisture-releasing element may be used.

In an alternative embodiment, however, instead of using a one way semi-permeable membrane 14, a porous or fully permeable bidirectional membrane may be used instead. This embodiment would be particularly applicable to situations in which tobacco is to be transferred between a number of environments of different humidities, so that flexibility in the direction of moisture transfer is desirable. By allowing the moisture to be transferred from the tobacco to the moisture-containing layer 7 in humid conditions, excessive dampening of the tobacco can be avoided, whereas in dry conditions, the equilibrium of the system would shift so that moisture would be transferred to the tobacco to keep it at a desired moisture level.

The selection between the use of a one way semi-permeable membrane and a fully permeable membrane can therefore be made based on the intended use of the packaging.

The laminate structure of Figures 2 and 7 can be applied to the tobacco pouch 1 in its entirety, in other words of all of the walls of the pouch or just to specific parts such as the front and back faces of a substantially flat pouch. The design can be made with regard to the desired flexibility and weight of the packaging, and also the amount of tobacco 3 to be stored and its expected rate of use. For example, the moisture-containing layer can be designed to extend through all parts of the pouch walls, are can be confined to a limited area, with the pouch walls only formed of the polymeric material in areas where there is no moisture-containing layer.

When a portion of the moisture-containing layer 7 is exposed to the tobacco product, water is drawn along the paper layer to the exposed portion by osmosis as it evaporates into the pouch 1. Consequently, water can be drawn from all parts of the pouch 1 to reach a relatively small portion corresponding to a tear-off strip 12. In an alternative embodiment, however, the moisture-containing layer 7 can be partitioned to correspond to each of a plurality of tear-off strips 13a, 13b, 13c, so that as each strip is removed, the only water which is available to migrate to the tobacco 3 is that contained within a corresponding partitioned portion of the moisture-retaining layer 7. This arrangement may be effective where the rate of use of tobacco 3 is expected to be small, so that the humidifying effect can be controlled and prolonged accordingly.

The second polyethylene layer 8 can be printed so as to contain the branding of the manufacturer and product information. The paper in the moisture-containing layer 7 is preferably coloured white, to provide a suitable backing to the second polyethylene layer 8, and to prevent tobacco stains on the first polyethylene layer 6 being visible through to the outside of the pouch 1.

The tobacco pouch 1 according to embodiments of the present invention can be manufactured with a portion of the first polyethylene layer 6 already removed, so that a corresponding portion of the moisture-retaining layer 7 is exposed to the tobacco 3 at an initial stage. This enables tobacco 3 to be kept moist during shipping, or storage in a retail outlet prior to use.

In a further embodiment of the present invention, a humidity indicator can be included in the tobacco pouch 1, to provide guidance to a consumer. This may be particularly useful where the pouch 1 contains a plurality of tear-off strips 13a, 13b, 13c, as guidance can be given as to when individual strips should be removed. The indicator can be any type of compact humidity measuring device or sensor that gives a visual indication of the humidity level. A convenient example is a cardboard or paper device comprising one or more sensor areas of water-sensitive material that absorbs moisture from the atmosphere and changes colour according to whether humidity is above or below some threshold value. A range of sensor areas having different threshold values may be provided, to give a visual humidity scale from which the consumer can make a decision as to whether his tobacco product is sufficiently moist.

In a further embodiment of the present invention, shown in Figure 8, the first polyethylene layer 6 itself contains a semi-permeable one-way membrane portion 15 which enables water vapour to migrate from the moisture-containing layer 7 to the tobacco products 3 in the pouch 1, but prevents the water vapour migrating in the reverse direction. By forming the semi-permeable portion 15 in the first polyethylene layer 6 itself, a reduction in the size and weight of the packaging can be achieved by avoiding the need to form an additional semi-permeable layer over the first polyethylene layer 6. As described above, the one way semi-permeable membrane may be substituted for a porous/permeable membrane where desired.

The permeable/semi-permeable portion 15 of the polyethylene layer 6 may be of any appropriate size, depending on the desired exposure of moisture to the products 3 of the pouch 1. The portion 15 may form the whole of the interior of the pouch 1 where a higher degree of moisture transfer is required.

By using such a permeable/semi-permeable portion, the moisture-containing layer can maintain the pouch and its contents at a desired moisture level without any consumer interaction, such as removal of portions of the laminate material.

It is possible to use a plurality of semi-permeable or permeable/porous portions in the pouch, distributed evenly across the interior of the pouch 1 or localised in a particular region, such as the centre, in order to maximise the efficiency of the moisture transfer. It is also possible to use a combination of semi-permeable, permeable/porous portions and removable tear-off strips 10 (as described in the embodiments above), in order to provide a base level of humidification which does not require user control, but to provide an option of a "top-up" humidifying effect, through removal of the tear-off strips, to be used in drier conditions. Below the tear-off strip 10 can either be moisture-containing layer 7 or a membrane 14 in contact with the moisture-containing layer 7 as described in the embodiments above.

The first and second polyethylene layers 6, 8 need not be made of the same material as each other. The materials are typically plastics materials, and polypropylene, polystyrene, polyethylene terephthalate and polyactic acid may be used as an alternative to polyethylene. Preferably, the outer layer of the tobacco pouch 1 should be recyclable and/or biodegradable, while preventing the release of moisture from the moisture-containing layer to the environment. The inner layer of the tobacco pouch should be easy to arrange into tear-off strips, which are sufficiently strongly connected with the interior layer so as to present a watertight seal to the moisture-containing layer 7 when not removed, but which can be separated along perforated perimeters 11 or pre-formed lines or weakness without excessive force.

Where the tobacco product which is to be contained by the packaging is of the form of a cigarette, or cigar, rather than as loose tobacco, the pouch described above can form an inner shell 17 in a package 16 having a rigid outer frame 18, for example as shown in Figure 9. The walls of the outer frame 18 of the packet could be manufactured from a stiff, resilient material such as cardboard or plastic or a similar material demonstrating the rigidity required for a hinged-lid packet, for example, as shown in Figure 9, so as to protect its contents. The inner shell 17 is inserted into the outer frame 18 during the manufacturing process, and may either be secured to the outer frame 18 by an adhesive, or could be partially or fully removable from the outer frame 18 during use to facilitate removal of tear-off strips 19 (shown at the upper portion of the inner shell 17 by way of example only), or control by the user of the humidifying effects described above. In Figure 9, the inner shell 17 is shown partially extending from the opened hinged-lid package 16.

In an alternative embodiment, the laminate packaging structure of the invention could be used as either a portion, or all of the outer frame 20 of a hinged-lid cigarette packet or case as shown in Figure 10, where there is no inner shell. The second polyethylene layer 8 would, in this embodiment, form the outer packaging, while the first polyethylene layer 6 would be exposed to the cigarettes contained by the packaging, in the same way as described above. The moisture-containing layer 7 could be exposed by removal of a tear-off strip 21, but a membrane may be used as described above The polyethylene layers 6, 8 in addition to demonstrating the required resistances and permeabilities to moisture, could be reinforced with resilient material suitable for maintaining the packaging shape required to protect the contents of the packet.

It will be appreciated that the laminate structure of the packaging described can be formed into a number of different containers, such as flexible bag-like pouches, and more rigid pouches such as bags, cases or hinged-lid packets for cigarettes, cigars, cigarillos and the like, the moisture-transfer operation from the laminate structure being present in each.

It will be also appreciated that the packaging of the present invention can be used to store any product which requires hydration during storage, and not just tobacco.