WO2015197636A1

WO2015197636A1 - Moisture control sachet

Info

Publication number: WO2015197636A1
Application number: PCT/EP2015/064142
Authority: WO
Inventors: David IBBITSON
Original assignee: Essentra Packaging & Security Limited
Priority date: 2014-06-24
Filing date: 2015-06-23
Publication date: 2015-12-30
Also published as: GB2527532A; GB201411214D0

Abstract

The present application describes a moisture control sachet having a packet with a predetermined moisture vapour transmission rate and a moisture absorbent pad disposed therein.

Description

MOISTURE CONTROL SACHET

This invention relates to a moisture control product for product packaging which is capable of controlling the moisture levels of the atmosphere within the packaging. In particular, but not exclusively, the invention relates to a moisture control sachet which is capable of controlling the transmission of moisture between the moisture absorbent pad and the atmosphere outside the sachet.

It may be desirable to control the moisture content (or humidity) of the atmosphere in which perishable products are stored in order to prevent them from deteriorating. For example, in order to prevent tobacco from drying out it is beneficial to store it in an atmosphere that is not too dry. In another example, in order to prevent biscuits from going stale it is beneficial to store them in an atmosphere that is not too moist. Perishable products, such as tobacco and food, are often stored in a sealed container in an attempt to keep them fresh. However, the seal on such containers is never perfect, particularly if the containers are disposable. Therefore, over time, the perishable product may either dry out, or absorb water and become damp. It is known for consumers to attempt to control the moisture levels in product packages containing tobacco by adding e.g. potato, orange or apple peel to the package. The effectiveness of this approach is questionable. However, in recognition of the need to control moisture levels in product packaging, a number of moisture control devices and systems have been proposed which facilitate the transfer (release or absorption) of moisture to/from product packaging.

For example, it is known to provide a moisture control pad comprising a water absorbent layer which is capable of controlling the humidity of the atmosphere within the packaging. The water absorbent layer can be wetted by a user such that, in use, water evaporates from the surface so as to humidify (i.e. provide moisture to) the atmosphere within the packaging. The moisture control pad may therefore be used to prevent a product from drying out. In another arrangement, the water absorbent layer is provided to dry, or dehumidify the atmosphere within the packaging (i.e. absorb water from the atmosphere). The moisture control pad may therefore be used to prevent a product from absorbing water. A moisture control pad comprising a water absorbent layer is the subject of an earlier patent application by the same applicant entitled "Moisture Control Label" and having publication number: WO2014/076488. The entire content of WO2014/076488 is hereby incorporated into the present disclosure by way of reference thereto.

The arrangement disclosed in WO2014/076488 whilst satisfactory, suffers from a number of problems. In the case of the moisture control pad being used to provide moisture to a product such as tobacco, and due to the fact that an end user is responsible for wetting the pad, the precise amount of water ultimately added to the pad can vary. Furthermore, in order to maintain the amount of water held within the pad at an optimum level, the user is expected to re-wet the pad periodically. The required frequency of re-wetting depends on one or more variable factors, such as how often the product packaging is opened.

A further problem suffered by this prior arrangement is that the product or substance contained within the may come into direct contact with the hydrated pad.

It is therefore desirable to provide a means for controlling the moisture content of the atmosphere within product packaging which alleviates the aforementioned problems. It is particularly, though not exclusively desirable to be able to provide moisture to the atmosphere within product packaging at a rate which is controllable and more consistent over time, and with less reliance on user interaction. According to a first aspect of the invention there is provided a moisture control sachet for controlling the humidity of the atmosphere within product packaging, comprising: a packet which is permeable to water vapour and a water absorbent pad disposed within the packet, wherein the packet has an opening through which the water absorbent pad can pass.

The packet, or pouch, has an opening through which the water absorbent pad can pass, to allow the pad to be removed, wetted and replaced. Thus, a user removes the water absorbent pad from the pouch, hydrates it, and the replaces the wetted pad within the packet to provide a moisture control system for an item of product packaging. The packet having the wetted water absorbent pad disposed therein is deposited within the interior of the product packaging. The packet may be adhered to an inside surface of the product packaging, such as an inside wall or underneath the lid of the product packaging.

The packet advantageously provides a physical barrier between the water absorbent pad and the atmosphere within the product packaging. This is beneficial since the wetted pad does not come into direct contact with a substance contained within the product packaging. Moreover, since the packet is permeable to water vapour, moisture can still be transmitted through the packet between the moisture absorbent pad and the atmosphere within the product packaging.

The packet preferably exhibits a predetermined moisture vapour transmission rate (MVTR). Thus, the packet is advantageously capable of controlling the rate of transmission of water vapour through the packet, e.g. from the water absorbent pad to the atmosphere of the product packaging in the case of a product or substance which benefits from being stored within a relatively moist atmosphere, or from the atmosphere of the product packaging to the water absorbent pad in the case of a product or substance which benefits from being stored in a relatively dry atmosphere.

The MVTR of the packet determines how long the pad will be able to maintain a required level of hydration or moisture within the atmosphere of the product packaging. Thus, by controlling the rate of transmission of water vapour from the pad to the atmosphere of the product packaging it is possible to maintain the moisture level within a preferred range over a period of time. This alleviates the need for repeated consumer interaction and reduces the frequency at which the pad needs to be rewet by an end user.

Optionally, the packet is formed of a film. The moisture control sachet may optionally comprise a packet formed of a cellulose film or a regenerated cellulose film.

Optionally, the regenerated cellulose film is provided with a coating. The coating(s) applied to the film may determine the moisture vapour transmission rate of the packet.

Some examples of MVTR rates for coated/uncoated plastic films are as follows:

Film type MVTR (g/m2.24hrs) 38deg C 90% RH

Heat Sealable BOPP 5

1 Side acrylic 1 Side PVdC BOPP 3.6 Uncoated Cellulose Film 1600

Semi-permeable Nitrocellulose PVdC 900

PVdC coated Cellulose Film 10 Where RH is the relative humidity.

Some possible coatings which may be applied to packaging films include acrylic, PVdC and Nitrocellulose. All of these coatings will tend to lower the MVTR of any film. In the case of a BOPP film the coatings will have a relatively small affect on the MVTR due to the fact that BOPP has a very low MVTR rate to start with. In the case of cellulose film, a more dramatic reduction in the MVTR can be achieved by the addition of a coating to the film. For example, the MVTR of an uncoated cellulose film is around 1600, the MVTR of a cellulose film coated with nitrocellulose is around 900 and the MVTR of a cellulose film coated with PVdC is around 10.

The use of a film, in particular a regenerated cellulose film, offers many advantages such as ease of manufacture, low cost, biocompatibility and biodegradability. For example, it is advantageous for the packet to be formed from two films which are bonded together in such a way as to form a cavity between the two sheets into which the water absorbent pad is received. For example, a packet may be formed of two films of a similar shape and size which are bonded together at the edge portions thereof leaving a gap to form the opening to allow access to the interior cavity formed between the two films. By changing the area and properties of the coating applied to the cellulose film, it is possible to vary the moisture vapour transmission rate MVTR of the packet and, thus, to control the rate at which moisture is provided to, or removed from, the atmosphere within product packaging. It is therefore possible according to certain embodiments of the invention for the moisture level inside the packaging to be maintained within a particular range. Thus, it is possible to select the MVTR of the packet in accordance with the moisture level range appropriate for the particular substance to be contained within the packaging.

Optionally, the packet may be formed of a film, such as a polypropylene film or a BOPP film, provided with a plurality of perforations which are capable of allowing water vapour to be transmitted through the film. Optionally, the size and the spacing of the perforations determines the moisture vapour transmission rate (MVTR) of the packet. The perforations may be micro perforations.

The microperforations can be achieved either through hot or cold mechanical needles, electrostatic discharge, laser perforation, flame perforation or punching perforation. Typical hole sizes would range from 60 - 125 microns up to 5 mm depending on method used.

Optionally, the packet comprises closing means to allow the opening to be closed. The closing means may comprise a reseal portion.

Thus, after replacing the wetted pad into the packet, a user can close the packet such that the moisture is held within the packet. Thus the primary, and preferably the only, way for moisture to escape the packet is by transmission through the walls of the water vapour permeable packet itself.

Optionally, the reseal portion is provided on a flap of the packet which can be folded over the opening in order to close the opening, the reseal portion being arranged to allow the flap to be adhered to a portion of the packet.

Thus, after replacing the wetted pad inside the packet, the consumer will fold the flap over the opening and apply pressure to the reseal portion in order to adhere the flap closed over the opening. This advantageously results in a completely sealed moisture control sachet wherein the transmission of water vapour between the pad and the atmosphere outside the sachet is controlled and determined by the MVTR of the packet.

Optionally, the water absorbent pad comprises a fibrous pad. Optionally, the fibrous pad comprises polyolefin fibres.

In a particularly preferred embodiment the moisture absorbent pad comprises a polyolefin non-woven pad and the packet comprises regenerated cellulose film with at least one coating applied thereto, the coating having properties which determine, at least to some extent, the rate of moisture transmission through the film. Thus, certain embodiments combine two very different materials - the polyolefin pad and the cellulose film - which are typically used for quite different purposes, in order to provide a controlled moisture delivery system which benefits from the individual properties of those materials.

Optionally, the packet is provided with an adhesive portion, such as a reseal adhesive, on an outer surface thereof to allow the packet to be adhered to an interior surface of the product packaging. The adhesive portion may optionally comprise a pressure sensitive adhesive.

The water absorbent pad may comprise a fibrous pad or layer. The fibrous pad or layer may be woven or non-woven (such as a mat) and may comprise polymer fibres. The fibrous pad may comprise polyolefin fibres and/or polyethylene terephthalate (PET) fibres and/or polyethylene (PE) fibres and/or nylon fibres and/or polyvinyl chloride (PVC) fibres and/or polylactic acid (PLA) fibres. In other embodiments the water absorbent pad may comprise cellulose and/or paper and/or cotton. The water absorbent pad may be porous. The water absorbent pad may comprise a hydrophilic material. The hydrophilic material may comprise a hydrogel. The water absorbent pad may comprise a sponge material. The water absorbent pad may be a continuous layer.

The water absorbent pad may only be capable of absorbing less than 10ml, less than 8ml, less than 6ml, less than 4ml, less than 3ml, less than 2ml or less than 1 ml of water. Further, the water absorbent pad may be capable of absorbing greater than 0ml, greater than 0.1 ml, greater than 0.2ml, greater than 0.3ml, greater than 0.4ml, or greater than 0.5ml of water. The water absorbent pad may be capable of absorbing at least 0.6ml of water. The water absorbent pad may be capable of absorbing between 0.2-2ml, 0.3-1.5ml, 0.4-1 ml or 0.5-0.8ml of water.

The water absorbent pad or layer may have a thickness of less than 5mm, less than 4mm, less than 3mm or less than 2mm. The water absorbent pad may have a thickness of at least 0.1 mm, at least 0.2mm, at least 0.4mm, at least 0.6mm, at least 0.8mm or at least 1 mm. The water absorbent pad may have a thickness of between 0.1 mm-5mm, 0.2mm-4mm, 0.3mm-3mm, 0.5mm-2mm, or 0.7mm-1 .8mm.

The water absorbent pad may have an area (in plan view) of less than 100cm², less than 80cm², less than 60cm², less than 40cm², less than 20cm², less than 10cm², or less than 8cm². The water absorbent pad may have an area (in plan view) of greater than 0.1 cm², greater than 0.2cm², greater than 0.5cm², greater than 1 cm², greater than 1 .5cm², greater than 2cm², greater than 3cm², greater than 4cm², greater than 5cm², greater than 6cm², or greater than 7cm². The water absorbent pad may have an area (in plan view) of between 0.2-20cm², 0.5-15cm², 1.5-10cm², or 3-8cm². The water absorbent pad may have a density of less than 1 g/cm³, less than 0.9g/cm³, less than 0.8g/cm³, less than 0.7g/cm³, less than 0.6g/cm³, less than 0.5g/cm³, less than 0.4g/cm³, less than 0.3g/cm³, or less than 0.2g/cm³. The water absorbent pad may have a density of greater than 0.01 g/cm³, greater than 0.02g/cm³, greater than 0.03g/cm³, greater than 0.04g/cm³, greater than 0.05g/cm³, greater than 0.06g/cm³, greater than 0.07g/cm³, greater than 0.08g/cm³, greater than 0.09g/cm³, or greater than 0.1 g/cm³. The water absorbent pad may have a density of between 0.01 -1 g/cm³, 0.02- 0.9g/cm³, 0.03-0.8g/cm³, 0.05-0.7g/cm³, 0.08-0.5g/cm³, 0.09-0.3g/cm³, or 0.1 -0.2g/cm³.

The water absorbent pad may further comprise a base layer to which a water absorbent layer is adhered to (either directly or indirectly) on a front side. The base layer may be a uniform layer of material or may be a laminate structure. The base layer may be larger than the water absorbent layer such that a display region extends beyond the periphery of the water absorbent layer. Use instructions and/or commercial graphics may be provided on the display region of the base layer. The water absorbent layer may be located centrally with respect to the base layer. The base layer and/or the water absorbent layer may be circular, square, triangular or any suitable shape. If circular, the base layer and water absorbent layer may be concentric with one another.

The base layer may have a thickness of at least Ι Ομηη, at least 25μη"ΐ, at least δθμηη, at least 75μηι or at least Ι ΟΟμηη. The base layer may have a thickness of less than 1 mm, less than 0.5mm, less than 0.25mm, or less than 0.15mm. The base layer may have a thickness of between 10μη-ι-1000μη-ι, 20μΓΤΐ-700μη-ι, 50μΓΤΐ-500μη-ι, 60-250μη-ι, or 80μηΊ-150μΓΤΐ. The base layer may comprise polypropylene. The base layer may comprise mono- oriented polypropylene. The base layer may comprise polyethylene terephthalate (PET), polyethylene (PE) or polyvinyl chloride (PVC).

The water absorbent layer may be adhered to the base layer with a pressure sensitive adhesive, for example. The adhesive layer may comprise a pressure sensitive adhesive. According to a second aspect of the invention there is provided a moisture delivery system for delivering moisture to the atmosphere inside an item of product packaging, the system comprising a moisture permeable barrier and a water absorbent pad, wherein the moisture permeable barrier is capable of controlling the rate of

transmission of moisture from the water absorbent pad to the atmosphere inside the packaging.

Optionally, the water absorbent pad comprises a hydrophilic material. Optionally, the water absorbent pad comprises a hydrogel.

According to a third aspect of the invention there is provided a moisture permeable packet having an opening to allow access to the interior of the packet, the moisture permeable packet having a predetermined moisture vapour transmission rate.

The moisture permeable packet is for the moisture control sachet according to an embodiment of the first aspect. Optionally, the moisture permeable packet is formed of a cellulose film having one or more coatings selected so as to control the MVTR of the packet.

According to a fourth aspect of the invention there is provided a method of

manufacturing a moisture control sachet according to an embodiment of the first aspect, or a moisture delivery system according to an embodiment of the second aspect or a moisture permeable packet according to an embodiment of the third aspect.

According to a fifth aspect of the invention there is provided product packaging having a moisture control sachet according to an embodiment of the first aspect, or a moisture delivery system according to an embodiment of the second aspect or a moisture permeable packet according to an embodiment of the third aspect.

Features of each of the above described aspects are applicable to any of the other aspects. Embodiments of the invention may comprise any combination of the features and/or limitations referred to herein, except combinations of features that are mutually exclusive. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, the accompanying drawings in which: Figure 1 schematically shows a plan view of an example of a moisture control sachet;

Figure 2 schematically shows a cross sectional view through an example of a moisture control sachet; Figures 3A to 3D schematically show the application of water to an example moisture control sachet;

Figure 4 schematically shows a moisture control sachet in conjunction with a product tin; and

Figure 5 shows product packaging having a moisture control sachet.

Figures 1 and 2 shows a moisture control sachet 10 for controlling the moisture levels of the atmosphere within an item of product packaging. Figure 1 schematically shows a plan view of the moisture control sachet 10. Figure 2 schematically shows a cross sectional view through the moisture control sachet 10. The moisture control sachet comprises a packet 12 having disposed therein a moisture absorbent pad 14 as indicated by the dashed lines. The packet is provided with an opening 16 through which the water absorbent pad can pass.

Moisture is capable of being transmitted through the packet 12, either from the surrounding atmosphere to the moisture absorbent pad 14, thereby acting as a dehumidifier, or from the moisture absorbent pad 14 to the surrounding atmosphere, thereby acting as a humidifier. In this embodiment the packet is formed of a regenerated cellulose film. One or more coatings, which may comprise acrylic, PVdC, or nitrocellulose to name a few, applied to the film are selected to control the rate at which moisture is capable of being transmitted through the packet, i.e. the MVTR. In this embodiment the moisture absorbent pad comprises a polyolefin nonwoven moisture pad. In this embodiment, the packet 12 and the moisture absorbent pad are substantially rectangular in shape. The packet dimensions are approximately 50mm by 30mm. The thickness of the moisture absorbent pad is of the order of a few mm. It should be appreciated that various other shapes and dimensions could alternatively be used and that the dimensions and the shape of the packet will be at least partially determined by the package size and space allowed and by the amount of water that needs to be imparted per day and for how long. The packet is formed of two thin film layers which are substantially the same shape and size. The two thin film layers are bonded, heat sealed or laminated together along three edge portions 18, leaving the fourth edge portion open for access to the interior of the resultant packet.

In the case of the moisture control sachet being for providing moisture to an atmosphere in order to prevent a product, such as tobacco from drying out, an end- user or consumer removes the pad 14 from the packet 12 via the opening 16 and applies water to wet the pad. Preferably, a consumer applies sufficient water to saturate the pad. The wetted pad is then replaced within the packet 12 via the opening 16 and the moisture control sachet is placed within the item of product packaging.

Figure 3 illustrates schematically the application of water to moisture control sachet 20 according to a second embodiment of the invention. The moisture control sachet comprises a packet 22 shown in Figure 3A and a moisture absorbent pad 24 shown in Figure 3B. In order to act as a humidifier for product packaging, the moisture absorbent pad 24 is saturated with water and returned to the packet via the opening 26. The packet 22 comprises a flap 21 which is capable of being folded over the opening 26 in order to close the opening. A resealable adhesive strip 23 is provided which adheres to the surface of the packet when the flap is folded over, thereby securing the flap in a closed position whereby the opening is closed and the packet is sealed on all sides as shown schematically in Figure 3D. In this configuration, the packet provides a controlled environment for the moisture absorbent pad whereby water vapour can only reach the atmosphere surrounding the sachet via the walls of the packet itself. Thus, the rate of moisture vapour transmission from the pad to the atmosphere surrounding the sachet is substantially determined by the MVTR of the packet. Figure 4 schematically shows the use of a moisture control sachet 10 in conjunction with product packaging. The product packaging comprises a tin 30 which is intended to store loose (or rolling) tobacco. The moisture control sachet 10 is similar to the moisture control sachet shown in Figure 3 and comprises a flap for closing the packet. The moisture control sachet of Figure 4 also comprises an adhesive patch 25 on the side of the packet opposite to the side on which the reseal strip 23 adheres to. This allows the moisture control sachet to be adhered to the underside of the lid 32 of the tin 30.

It is desirable to prevent tobacco stored within the tin 30 from drying out as this can be detrimental to the quality of the tobacco. Therefore, the moisture control sachet 10 with wetted moisture absorbent pad 12 is applied to the underside of the tin lid 32 so that it is disposed within the tin when the lid is placed on the base of the tin. In another arrangement, the moisture control sachet 10 with wetted moisture absorbent pad is simply returned to the tin with the loose tobacco. Figure 5 schematically shows two further examples of product packaging, both typically used to store loose or rolling tobacco. Figure 5A shows a pouch 40 and the inclusion of a moisture control sachet 10 adhered to an inner surface of the pouch. Figure 5B shows a bag 50 also provided with a moisture control sachet which has been adhered to an inner wall of the bag. After purchasing a product contained in packaging as shown in Figures 5A or 5Bor as shown in Figure 4, for example, a user will remove the moisture control sachet which is disposed amongst the substance stored within the packaging. The user will remove the moisture absorbent pad from the packet and wet the pad. Once the pad has been wet, it is returned to the packet. A user then removes a protective release layer which is provided over an adhesive patch provided on the moisture control sachet and presses the moisture control sachet to an inner wall of the pouch or bag or to the underside of the tine lid 32 in order to adhere the moisture control sachet to the interior of the product packaging.

Claims

CLAIMS:

1 . A moisture control sachet for controlling the humidity of the atmosphere within product packaging, comprising:

a packet which is permeable to water vapour; and

a water absorbent pad disposed within the packet;

wherein the packet has an opening through which the water absorbent pad can pass.

2. A moisture control sachet as claimed in claim 1 wherein the packet exhibits a predetermined moisture vapour transmission rate.

3. A moisture control sachet as claimed in claim 1 or 2, wherein the packet is formed of a film.

4. A moisture control sachet as claimed in claim 3, wherein the packet is formed of cellulose film.

5. A moisture control sachet as claimed in claim 4, wherein the regenerated cellulose film is provided with a coating which determines the moisture vapour transmission rate of the packet.

6. A moisture control sachet as claimed in claim 5, wherein the coating may comprise one or more of: nitro-cellulose, PVdC and Acrylic

7. A moisture control sachet as claimed in claim 4, wherein the film is provided with a plurality of perforations, wherein the size and the spacing of the perforations determines the moisture vapour transmission rate (MVTR) of the packet.

8. A moisture control pouch as claimed in claim 7, wherein the perforations are between 60 microns and 0.5mm in size.

9. A moisture control sachet as claimed in any preceding claim, wherein the packet comprises closing means to allow the opening to be closed.

10. A moisture control sachet as claimed in any preceding claim, wherein the closing means comprises a reseal portion.

1 1 . A moisture control sachet as claimed in claim 10, wherein the reseal portion is provided on a flap of the packet which can be folded over the opening in order to close the opening, the reseal portion being arranged to allow the flap to be adhered to a portion of the packet.

12. A moisture control sachet as claimed in any preceding claim, wherein the water absorbent pad comprises a fibrous pad.

13. A moisture control sachet as claimed in claim 12, wherein the fibrous pad comprises polyolefin fibres.

14. A moisture control sachet as claimed in any preceding claim, wherein the water absorbent pad comprises a hydrophilic material.

15. A moisture control sachet as claimed in claim 14, wherein the hydrophilic material comprises a hydrogel.

16. A moisture control sachet as claimed in any preceding claim, wherein the packet is provided with an adhesive portion on an outer surface thereof to allow the packet to be adhered to an interior surface of the product packaging.

17. A moisture permeable packet having an opening to allow access to the interior of the packet, the moisture permeable packet having a predetermined moisture vapour transmission rate.

18. Product packaging comprising a moisture control sachet as claimed in any one of claims 1 to 15.

19. A moisture control sachet or product packaging substantially as described herein with reference to the accompanying drawings.