Moisture Regulating Element for Use In Packaging

Abstract

A moisture-regulating element for use in packaging is claimed, which comprises a layer of pulp fibres and optionally further layers, characterized in that the element contains means which are able to regulate the moisture content.

The moisture-regulating element may be used in packaging for the transport and other storage of moisture-sensitive products or can serve as such, in order to store these products under optimal moisture conditions.

Claims

1-15. (canceled)

16. A method comprising regulating the moisture level in a package comprising using a moisture regulating element in the package, the moisture regulating element comprising a layer of pulp fibres characterized in that the layer of pulp fibres is substantially built up from a loose filling of pulp fibres loosened in an air stream to provide a plurality of first areas of pulp fibres comprising loose, airlaid pulp fibers and plurality of second areas comprising compacted, airlaid pulp fibers connected to one another in an adhesive free or binder free manner, in which one of the plurality of second areas is present between and connects the plurality of first areas, wherein the layer further comprises solid material disposed on the pulp fibers of the first areas and the second areas, in which each of the disposed solid material and the pulp fibers of the first areas and the second areas are positioned in the layer to adsorb and to release moisture to regulate moisture content in a the package comprising the element, wherein the solid material present on the pulp fibres in each of the first areas and the second areas to regulate the moisture content and is selected from the group consisting of inorganic salts, sugars, starches or modified starch products, alkali and alkaline earth metal salts of alcohols, silicates and mixtures thereof, and wherein the solid material upon contact with the air can draw moisture from the air or give up moisture to the air to regulate the moisture level in the package.

17. The method of claim 16, further comprising configuring the inorganic salts to be selected from the group consisting of sodium chloride, potassium chloride, zinc chloride, sodium carbonate, potassium carbonate, sodium sulphate, potassium sulphate, sodium nitrate, potassium nitrate, sodium hydroxide, potassium hydroxide, calcium chloride and calcium oxide.

18. The method of claim 16, further comprising configuring the sugars to be selected from the group consisting of fructose, glucose and saccharose.

19. The method of claim 16, further comprising configuring the alkali and alkaline earth metal salts of alcohols to be an alcoholate of glycerine or an alcoholate of glycerol.

20. The method of claim 16, further comprising configuring the silicate to be a silica gel, zeolite, kaolin or bentonite.

21. The method of claim 16, further comprising configuring the moisture regulating element with a base layer arranged above or below the layer of pulp fibres.

22. The method of claim 16, further comprising configuring the moisture regulating element with a cover layer arranged on a side opposite the base layer.

23. The method of claim 22, further comprising on configuring the base layer and the covering layer to be a same or different and to each be a nonwoven or tissue.

24. The method of claim 22, further comprising configuring the moisture regulating element with an additional layer arranged on the base layer or the cover layer.

25. The method of claim 24, further comprising configuring the additional layer to be a same or different material as the base layer or the cover layer, wherein the additional layer comprises one of cotton, a nonwoven or perforated film.

26. The method of claim 16, further comprising pressing the airlaid pulp fibers using pressure and heat to provide the pressed areas.

Description

[0021] The element according to the invention will be explained in more detail below by using an exemplary embodiment and with reference to the drawing, in which:

[0022] FIG. 1 shows a greatly enlarged partial section through the element,

[0023] FIG. 2 shows a greatly enlarged partial section through a multilayer element,

[0024] FIG. 3 shows a greatly enlarged section through a further multilayer element,

[0025] FIG. 4 shows a partial section through a packaging.

[0026] FIG. 1 shows a partial section through the moisture-regulating element 12 according to the invention. This element has a layer 1 which has a high proportion of pulp fibres 2, in which moisture-binding means 3 are incorporated. The layer 1 forms the core of the element 12.

[0027] The pulp fibres 2 are compacted in the embossed areas 4 and in this way are connected to one another. In the embodiment illustrated here, the embossed areas 4 are located opposite one another on the upper and lower side, so that in the respective embossed area 4 only a narrow web of interconnected pulp mass remains. The other areas of the layer 1, arranged between the respective embossed areas 4, exhibit looser pulp layering. An intimate connection between the pulp fibres 2 does not exist in these areas.

[0028] The adsorption behaviour and the retention capacity of moisture is determined by the layer 1 made of pulp fibres 2 and the moisture-binding means 3 used and, if appropriate, further materials which can be incorporated in the layer 1. In the embodiment illustrated here, the layer 1 in the embossed areas 4 has the shape of truncated pyramids or truncated cones; the angle of the slopes formed should preferably lie between 10° and 45°.

[0029] Bulk material that is presently available inexpensively can be used as pulp material for the fibrous web 1. Use is preferably made of what is known as fluff-pulp, which is distinguished by a very good binding behaviour, which improves the mechanical strength of the element with respect to vertical tensile forces.

[0030] During the production of the element according to the invention, first of all a web material is produced, which is then cut to the desired size. For the production of the web material in a continuous process, the fibrous web later forming the layer 1 is produced from a loose filling of fibres 2 loosened in the air stream and made of defibered pulp (wood pulp) and the moisture-binding means 3 and, if appropriate, further incorporated materials. For the production of a standardized, defiberized product, recourse can be had to renewable wood raw materials available on the market.

[0031] The loose pulp filling process as a starting product for the layer 1 permits dry processing of the pulp fibres 2 and therefore, during the subsequent embossing of the multilayer web between two structured rolls, very good compaction of the pulp fibres in the discrete embossed areas 4. Outside these embossed areas 4, the fibres lie loosely on one another, which influences the behaviour of the incorporated moisture-binding means to the effect that the moisture does not impair the predefined binding capability according to the binding capacity (hygroscopicity), moreover, as a result of the loose layering of the fibres between the respective embossed areas, the flexibility of the element 1 is improved and, when the element 1 is used in packaging, it serves simultaneously as a protection against shocks, etc. for the product to be packaged. The element according to the invention can be used as an inlay in foodstuffs packaging, for example for convenience products, bread, sausage products including meatballs.

[0032] The production of the element according to the invention is carried out preferable from web material, which is fabricated in a continuous process. In air-assisted layering, firstly the pulp fibres 2 and the means 3 able to bind moisture and, if appropriate, further additives for binding the layer 1 are laid. Then, the production of the embossed areas 4 is carried out in a calender having two structured calender rolls. A possible production method is disclosed, for example, in European Patent 1 032 342.

[0033] Depending on how thick the finished web is intended to be, it is also possible to lay a plurality of layers made of pulp fibres 2 and means 3 and, if appropriate, further additives over one another and then to introduce them into the calender in order to obtain the embossed areas 4. In this way, the moisture-binding means is incorporated layer by layer in the web. A homogenous distribution is achieved if the moisture-binding means are processed together with the pulp fibres, that is to say distributed uniformly in the pulp fibres, to form web material.

[0034] A multilayer web 5, as illustrated in FIG. 2, can be produced, for example, by a covering layer 6 or a base layer 7 being used first as a carrier layer. The loose filling of pulp fibres 2 and the moisture-binding means 3 is then applied to this carrier layer 6 or 7 in the air stream. This arrangement made of carrier layer and loose filling is then led jointly through the structured rolls of the calender. Alternatively, the other of the two layers 6, 7, which is therefore not already a carrier layer, can also be laid on the pulp layer 1 previously, that is to say before the final leading through the calender.

[0035] The two layers 6 and 7 can also be applied subsequently, if appropriate with further layers, in a manner known per se. If the further layers are applied subsequently, they can have any desired surface structure, for example be smooth.

[0036] The embodiment illustrated in FIG. 2 shows a total of 3 layers, specifically a web assembled from the layers 6, 1 and 7.

[0037] The lowest layer is used as a base material and a layer is applied as an upper layer. The covering layer 6 has the advantage that the product to be packaged does not come directly into contact with the pulp fibres and the means adsorbing the liquid or moisture-regulating means, resp.

[0038] Suitable as a base material and also as a covering layer 6 are, in particular, those materials through which the water vapour can pass but which are impermeable to the moisture-binding/-regulating means incorporated. Examples of suitable materials are nonwoven-like materials and tissue based on plastic or cellulose.

[0039] The edges 14 of the element may be open or closed.

[0040] FIG. 3 shows an element according to the invention which has the same structure as the element from FIG. 2 but is surrounded by further layers 8 and 9. These further layers 8 and 9 can be larger than the layer 1 and/or the layers 6 and 7 possibly arranged thereon. The layers 8 and 9 can be the same or different and are used to match the properties of the element to the specific requirements of the products to be stored. These further layers can be connected to one another without the layer 1 and the layers 6 and 7 possibly arranged thereon also being gripped. These two layers form a sheath for the element. They can be made of textile, nonwoven-like or film-like material or tissue; at least one layer of such a sheath should be permeable to the moisture. The layers 8 and 9 are preferably chosen from cotton, nonwoven and/or perforated film.

[0041] In a possible embodiment one of the further layers 8 or 9 is impermeable for moisture. In such embodiment the layer 9 directed to the product may be permeable for moisture/liquid and the layer 8 directed to the package is liquid-impermeable. This embodiment prevents that liquid passes from the bottom of the package back to the product in case the capacity of the inventive element 12 is exceeded and due to the weight of the product 12 the liquid is squeezed out of the element 12 and collected at the bottom of package.

[0042] FIG. 4 shows a foodstuffs packaging comprising lower shell 10 and lid 11, into which an element 12 according to the invention has been inserted. The stored product 13 is laid on the element 12 and the packaging is closed by the lid 11.

[0043] A packaging illustrated in FIG. 4 was used to investigate the influence of the element according to the invention on the shelf life of stored foodstuffs. To this end, the element according to the invention was inserted into a packaging; for the purpose of comparison an element with an identical structure but without moisture-binding means was inserted. Different foodstuffs were stored in this packaging over a number of days; the visual appearance of these foodstuffs was compared.

TABLE-US-00001 Storage Visual appearance period According to the Stored foodstuff (days) invention Comparison Rolls 12 Slightly shrunk Clear signs of mould Rolls 17 Dry Completely affected by mould Toast 12 Unchanged Slight mould spots Toast 6 Dry and hard Completely surrounded by mould Fresh cheese 15 No condensation Considerable amounts of condensation Hard cheese 15 No condensation Considerable amounts of condensation Sandwich 2 No condensation, Bread very damp and bread not soggy soggy

[0044] As the above illustration makes clear, the shelf life of foodstuffs could be improved considerably.

[0045] The reduction in moisture and condensation not only leads to a prolongation of the shelf life, in addition the sensory impression of the foodstuffs is considerably better. Not only the appearance of the products but the storage after some days was still very good as compared with the conventionally stored foodstuffs, in addition the tactile properties were very much better, for example the bread which was used for the sandwiches was not soggy, as compared with the conventionally stored product.

[0046] In the case of fresh cheese, hard cheese, a considerable improvement in the visual properties can be observed. In the case of these products, only the sensory change was studied; a prolongation of the shelf life whilst maintaining optimal visual properties is also possible.

[0047] For ease of reference the following list of reference symbols is provided. [0048] 1 Layer [0049] 2 Pulp fibres [0050] 3 Moisture-binding means [0051] 4 Embossed area [0052] 5 Multilayer web [0053] 6 Covering layer [0054] 7 Base layer [0055] 8, 9 Further layer [0056] 10 Lower shell [0057] 11 Lid [0058] 12 Element according to the invention [0059] 13 Stored product [0060] 14 Edge