WO2008056035A1

WO2008056035A1 - Group package for sheet material and method for manufacturing the group package

Info

Publication number: WO2008056035A1
Application number: PCT/FI2007/050601
Authority: WO
Inventors: Matti SIPILÄ; Jarmo Järvinen
Original assignee: Upm-Kymmene Corporation
Priority date: 2006-11-10
Filing date: 2007-11-08
Publication date: 2008-05-15
Also published as: RU2401230C1; FI20065710A0; EP2117958A4; FI122251B; CN101588972A; EP2117958A1; CN101588972B; FI20065710A; US20100001050A1; JP2010509146A

Abstract

This invention relates to a group package (1) for sheet material such as printing and photocopy paper, and a method for manufacturing the protective wrap of the group package and the group package itself. In the group package (1), a number of paper bundles (Ia) wrapped in their own ream wraps (2a) consisting of at least a base paper layer (19a), are placed within a shared protective wrap (2). The material of the protective wrap (2) and of the wrap (2a) of the paper bundles (Ia) is formed by adding plastic, a polymer mixture or another suitable material to one or both of the materials, in suitable quantities to make the combined water vapour transmission rate (WVTR) of the protective wrap (2) and the wrap (2a) less than approx. 50 g/m2/d, as calculated according to the ISO 2528:1995 standard.

Description

GROUP PACKAGE FOR SHEET MATERIAL AND METHOD FOR MANUFACTURING THE GROUP PACKAGE

This invention relates to a group package for sheet material such as printing and photocopy paper, as described in the preamble to claim 1, and a method for manufacturing the group package and the wrapping materials used in connection with the group package, as described in the preamble to claim 11.

In known technology, office paper provided in sheet form, such as A4-sized photocopy and printing paper, is usually packaged in corrugated board boxes, each box containing five paper bundles wrapped in individual paper wrappings. Each paper bundle, known as a ream wrap, contains 500 A4-sized sheets of paper. A corrugated board box provides office paper with good protection during transport, but is problematic due to its cost and to the space taken up by the empty box before it is disposed of or recycled. In addition the box has a lid, tied down with a thin plastic band that in practice also acts as a carry handle. A problem with using a plastic band is how to dispose of it, and the fact that a thin plastic band is very uncomfortable for carrying the box, due to the weight of the five ream wraps contained in the box.

To address these drawbacks, alternative group package solutions have been developed for office paper. Packages have been created for example out of different wrapping papers that are wrapped around the ream wraps. The challenge with these kinds of wrappings is how to make the packages durable enough to withstand possible impacts during transport and storage. In addition, the package should protect the papers inside the ream wraps from moisture. Some of the critical strength properties of the wrapping are pulling resistance, tensile strain and bursting strength. There are known paper types that fulfil these strength criteria well enough to be used as wrappings for example in grouped ream wrap packages. The problem is that these paper types do not provide sufficient protection against moisture. Therefore in prior art the wrapping is coated with a plastic layer that provides moisture protection. Additionally, the plastic layer further enhances the wrapping's strength properties. The plastic layer can consist for example of a PE, PET or similar film, added onto the paper in a separate extruder.

A problem with plastic-coated wrappings is that due to their plastic content they are not as environmentally friendly as those without plastic. Further, the recycling costs of plastic-coated papers according to known technology are in most countries significantly higher than those of paper without plastic. Another problem is that the plastic coating requires a separate extruder and work phase, which increases costs and takes time.

The object of this invention is to remove the problems described above and achieve insofar as possible, an inexpensive group package for office paper, where little or no plastic is used, but which still protects the paper sheets well. In addition the object is to create a group package that is easy to carry and in which the weight is distributed evenly, for example onto both hands. Furthermore, the purpose of the invention is to achieve an affordable, quick and reliable method for producing the wrap materials for the grouped office paper bundle, as well as the group package itself. The group package described in the invention is characterised by what is disclosed in the characterisation part of claim 1. Similarly, the method described in the invention is characterised by what is disclosed in the characterisation part of claim 11. Other embodiments of the invention are characterised by what is disclosed in the other claims.

The benefit of the solution according to the invention is that the group package according to the invention is very cheap and quick to produce. Another benefit is that the packaging material has high bursting and tear resistance, so the group package protects well the paper bundles placed inside it and wrapped inside separate wrap papers. A further benefit is the fact that the group package and the ream wrap papers inside it can be produced of the same paper. Another benefit is that the invention facilitates the lifting of the group package using two hands, which distributes the load evenly between both hands. Thanks to suitably shaped carry handles or similar devices, the weight does not strain the hands in the way that previously used thin plastic strips do. A further benefit is that the packaging material is available in reels, which minimises the amount of wastage. Another benefit is that the wrapping uses very little or no plastic, which makes it environmentally friendly and cheap to recycle. Another benefit is that the wrapping is very resistant to moisture, even though there is no separate plastic layer. Similarly, when using wraps coated with a suitable layer, seams are easy to fuse using heat sealing or ultrasound. Another benefit is that the wrap is provided with at least one opening strip, which makes the wrap easier to open. A further benefit of a group package equipped with an opening strip is the fact that once open, the empty package can be used as a neat bag for other folded packages or other materials to be taken for recycling. Another benefit is that because the opening strip is placed at a suitable distance from the end of the group package, the ends of the separate bundles inside the group package are easy to see once the group package is open, so they are easy to remove from it.

Below, the invention is described in detail using application examples, by referring to the appended figures, in which

Figure 1 shows a group package according to the invention viewed diagonally from the side, Figure 2 shows a group package according to Figure 1, viewed diagonally from the side and with one end removed from the opening strip onwards, Figure 3 shows a group package according to Figure 1, viewed diagonally from the side before the end folds are glued down,

Figure 4 shows an embodiment of the invention viewed diagonally from the side, Figure 5 shows the carrying method for group packages according to Figures 1 and 4, viewed diagonally from the side,

Figure 6 shows a typical layer structure for the protective wrap according to the invention, in simplified and enlarged form, Figure 7 shows a second layer structure for the protective wrap according to the invention, in simplified and enlarged form, Figure 8 shows a third layer structure for the protective wrap according to the invention, in simplified and enlarged form,

Figure 9 shows a second embodiment of the invention viewed diagonally from the side, Figure 10 shows a third embodiment of the invention viewed diagonally from the side, Figure 11 shows a further embodiment of the invention viewed diagonally from the side, and Figure 12 shows one more embodiment of the invention viewed diagonally from the side.

Figures 1 and 2 display a group package 1 according to the invention. Office paper bundles Ia, for example the size of a ream wrap, containing A4-sized paper sheets, are packed into a group package 1 that forms a protective package 2 made out of strong protective wrapping. Each paper bundle Ia is additionally wrapped in its own paper-like wrap 2a. The group package is made out of a reel-based wrap, which is pulled directly off the reel during packaging and cut off at the correct length, after which the protective wrap 2 is rolled around a set of for example five horizontally piled, separate paper bundles Ia, such that the top, bottom and both long sides of the group package form a continuous wrapper, in which the back end 22 of the protective wrap 2 overlaps the forward end of the wrap by a suitable amount and is glued down by its inner surface to the outer surface of the forward end. The hidden forward end of the wrap 2 is indicated here and in other figures using a dashed line. The back end 22 of the wrap 2 is placed suitably on top of the group package, essentially close to one of its long corners. At each end of the group package there are at least outer folds 3 and 4 and inner folds 5 and 6, which folds are placed at least partially overlapping. The folds at the ends form a strengthened protection for the ends of the office paper sheets in the package, where even a small accident could easily cause damage to several sheets.

In the group package in Figure 1, the external folds 3 and 4 at the ends of the group package are glued using for example hot glue to each other and at least to the outer surface of the upper inner fold 5, such that at least the lower edges of the outer folds 3 and 4 are separate from the outer surfaces of the inner folds 5 and 6. Thus a downward-opening lifting gap 7 is left between the outer folds 3 and 4 and the inner folds 5 and 6, which gap can be expanded outward from the end of the group package 1 so that the person lifting the package can fit several fingers into the lifting gap 7 from below, while the lower edges of the outer folds 3 and 4 act as a support .

Figure 1 also has a dashed line indicating the opening strip 23, glued to the inner surface of the protective wrap 2 before the wrap is cut-off. Thus the opening strip 23 is essentially the same length or suitably longer than the protective wrap 2. The opening strip 23 is placed at a suitable horizontal distance from the end of the group package 1. A suitable distance is for example 1-4 cm, which leaves the ends of the paper ream wraps Ia inside the group package 1 suitably visible after the protective wrap 2 is opened, as shown in Figure 2. This makes the ream wraps Ia easier to remove from the group package. At the end of the opening strip 23, in line with the end 22 of the protective wrap 2, the edge of the protective wrap 2 is cut open such that at each side of the opening strip 23 there is a suitably long incision 24, lengthwise in line with the opening strip 23. This makes it easy to get hold of the end of the opening strip 23, and the protective wrap 2 can be torn open right around the group package 1. The material of the opening strip 23 can vary, but it is always sufficiently strong and essentially inelastic or very slightly elastic. The opening strip 23, hidden inside the protective wrap 2, is shown using a dashed line in Figure 1. The other figures, on the other hand, in which the opening strip 23 is visible, only display the end of the opening strip, which end is equipped with incisions 24.

Figure 2 shows a group package 1 according to the invention, opened at the opening strip 23 such that the topmost paper ream wrap Ia has been removed and the second ream wrap Ia has been pulled out of the group package 1 somewhat.

Figure 3 shows an implementation of the method according to the invention for producing a group package 1 according to the invention. The beginning of the work cycle can be a situation at which the products to be packed together in the group package are positioned ready for making the group package, i.e. for instance the paper bundles Ia are stacked in a pile of five ream wraps. The width of the wrapping that forms the protective wrap 2 according to the invention is designed to be greater by the desired amount than the length of the paper bundles Ia. The wrapping that forms the protective wrap 2 is taken directly off a reel and pulled along its width to be underneath the paper bundles Ia. An initial wrapping is conducted by wrapping the wrap 2 around the paper bundles Ia such that on at least one of the long sides of the group package 1, the back end of the protective wrap overlaps the forward end of the protective wrap. The back end of the protective wrap is optimally placed at the edge between two long ends, for instance at the edge between the top side and the front side, as shown in Figure 3. In the figures, the right-hand side of the group package acts as the front side.

When the reel-based protective wrap is cut into the correct length and wrapped around the paper bundles Ia, the end folds are formed by pressing the upper inner fold 5 downwards against the end of the group package 1. Similarly, the lower inner fold 6 is pressed upwards against the end of the group package 1. When the inner folds 5 and 6 are pressed against the end of the group package, the outer folds 3 and 4 are formed at the same time by folding the parts of the protective wrap 2 that exceed the length of the paper bundles at the vertical ends until they are doubled on top of each other, essentially forming two triangular folds. In order to ensure that the outer folds 3 and 4 overlap in their final position, the length by which the protective wrap exceeds the length of the paper bundles, on both sides of the group package, must be more than half of the width of the paper bundles. Length here refers to the long edge of for example A4 sheets, and width to their short edge. After making the folds, the outer folds 3 and 4 are glued at each end of the group package 1 at least to one of the inner folds 5 and β, and, if necessary, also to each other.

In packages with no carry handle, at each end of the group package 1, the outer folds 3 and 4 are glued to form a lifting gap 7 that allows the carrying and lifting of the group package 1, where the lower edge of the lifting gap 7 acts as the support for lifting and carrying.

In the solution shown in Figure 3, an essentially horizontal glue seam that acts as an attachment seam 8 is spread onto the outer surface of the upper inner fold 5, close to the lower edge of the inner fold 5, essentially along the whole width of the fold 5. Similarly, an essentially vertical glue seam that acts as an attachment seam 9 is spread on the inner surface of the outer fold 4, close to the outer end of the fold 4. After spreading the glue, the outer fold 3 that is further to the inside is pressed against the inner folds 5 and 6, after which the topmost outer fold 4 is pressed against the other outer fold 3 and the inner folds 5 and 6. This forms the group package 1 according to Figure 1, in which a lifting gap 7 is left at the lower edge of the outer folds 3 and 4 for lifting and carrying the group package. Thanks to the gluing method, there is a similar lifting gap at the top edge of the outer folds 3 and 4, which means that the group package can also be lifted when it is upside down.

Figure 4 shows a different gluing method also included in the concept of the invention. In this solution, the innermost outer fold 3 is glued, after being folded, by its inner surface to the outer surface of the inner fold 5, with a glue seam acting as an attachment seam 10, essentially placed close and parallel to the upper edge of the fold 3. Similarly, the outermost outer fold 4, which is folded over outer fold 3, is glued, after being folded, to the outer surfaces of inner fold 5 and outer fold 3, using a glue seam acting as an attachment seam 11 and another glue seam 12 acting as a continuation of the other attachment seam. This gluing method leaves a lifting gap 7 only at the lower edge of the outer folds 3 and 4, so the group package must be the right way up before being lifted.

Figure 5 shows a method for lifting and carrying a group package 1 produced in the ways listed above, by the lower edge of the outer folds 3 and 4, where the lifting gap 7 allows fingers to be inserted between the outer folds 3 and 4 and the inner folds 5 and 6. Thanks to the attachment seams 8 and 9 or 10-12, the group package's protective wrap 2 can withstand the lifting and carrying of the package. Figures 6-8 show some typical layer solutions for the protective wrap according to the invention. The wrapping that forms the protective wrap 2 according to the invention, and the wrap 2a of the paper bundles Ia, or at least one of these wraps must fulfil certain requirements related to at least protectiveness, bursting strength, tear resistance, gluability and printability . In addition the wrapping that forms the protective wrap 2 and/or the wrap 2a of the paper bundles Ia must protect the contents of the package from moisture. One beneficial embodiment of the invention makes both the protective wrap 2 and the wrap 2a of the paper bundles Ia hydrophobic, i.e. water-repellent. Thus the material of the wrap forming the protective wrap 2 for the group package 1 and the material of the wrap 2a around the paper bundles Ia can for example be formed such that the base layer 19 of the protective wrap 2 and the base layer 19a of the wrap 2a around the paper bundles Ia are made of paper, to which an additive is added during production as online coating in the paper machine' s coating section, which additive consists of plastic, a polymer mixture or a similar suitable material 20 that slows down moisture absorption, in a suitable quantity that the total water vapour transmission rate (WVTR) of the protective wrap 2 and the wrap 2a, calculated according to the ISO 2528:1995 standard, is less than approximately 50 g/m /d, preferably a maximum of approx. 30 g/m²/d and favourably a maximum of 10 g/m²/d. Such polymers or polymer mixtures added during the paper' s production process are for example latex compounds and various mineral mixtures.

According to one of the embodiments of the invention, the wrapping that forms the protective package 2 and/or the wrap 2a of the paper bundles Ia is smooth, so that it can be coated in plastic more easily. In this case the wraps are coated at least on one side with a plastic film using a separate extruder, as is done in some known solutions. Thanks to the smoothness of the paper, less plastic has to be used than before. Suitable plastic films for this purpose include polyethylene (PE) films, polyethylene terephthalate (PET) films and polypropylene (PP) films.

A further embodiment of the invention consists of the combination of the two embodiments described above. In this solution, the wrapping of the protective wrap 2 and the wrap 2a of the paper bundles Ia consist of paper to which a polymer mixture or similar material has been added during production in the paper machine's coating section, after which a plastic film is added to the paper in a separate extruder.

The end result in each of the three embodiments of the invention described above is a protective wrap 2 of the group package 1 and a wrap 2a of the paper bundles Ia, in which the total quantity of plastic is essentially less than 10% of the total weight of the wraps. Favourably, the total quantity of plastic is a maximum of approx. 5% of the protective wrap' s 2 and the paper bundle wrap' s 2a total own weight. This makes the protective wrap and the ream wrap environmentally friendly and more recyclable, with reduced recycling costs.

Figure 6 shows the layer structure of one of the protective wraps 2 and/or paper bundle Ia wraps 2a according to the invention, simplified to show only the essential layers. In addition, the thicknesses of the layers are not to scale. The base of the wrap 2, 2a is formed by a base paper layer 19, 19a, more simply called the paper layer 19, 19a. Depending on the type of paper, the paper layer 19, 19a can have one or more layers. Only one layer is shown in the figure for simplicity. On top of the paper layer 19, 19a is a printing ink layer 18, which covers the surface of the paper layer 19, 19a at least partially. On the other side of the paper layer 19, 19a is a polymer layer added during the paper's production as online coating, or a similar layer 20 that slows down the penetration of moisture. .

Figure 7 has a similar structure to that in Figure 6, but the layer of polymer or similar material 20 that slows down the penetration of moisture is placed in between the printing ink layer 18 and the paper layer 19. Therefore the printing is done onto layer 20, which must be suitable for printing. In addition, an essentially thin plastic film 25, such as a PE, PET or PP film, has been added to the wrap 2,

2a in an extruder.

Figure 8 shows the layer structure of a third embodiment of the protective wraps 2 and/or paper bundle Ia wraps 2a according to the invention, simplified to show only the essential layers. In addition, the thicknesses of the layers are not to scale. The layer structure is similar to that in Figure 6. In this structure, a surface layer 21 is added to the top of the base paper layer 19, 19a, which surface layer can be fused using heat or ultrasound. In this case, instead of using separate glue, all previously mentioned seams that were glued, can be fused by heat sealing or ultrasound. The printing ink layer 18 does not have to go over the seams that will be fused.

In all of the layer structures in the abovementioned embodiments, and all other layer structures according to the invention not shown in the appended figures, the materials and thicknesses of the layers of the wrap are selected so that the total quantity of plastic in the different layers is a maximum of 10% of the individual total weight of the protective wrap 2 and the wrap 2a of the paper bundles Ia, and favourably a maximum of approx. 5%.

The layering and, particularly, the thickness of the protective wrap 2 and the wrap 2a of the paper bundles Ia can be used to regulate how resistant the paper bundles inside the group package 1 are to blows and impacts from the outside. At least the thickness of the protective wrap 2 should be such that the weight of the wrap is in the range 60-250 g/m². Depending on the wrap material, a suitable thickness range, expressed in weight, is 80-160 g/m². The thickness can suitably also be such that the weight is 120- 150 g/m².

In order for the protective wrap 2 to withstand the handling of group packages, the material of the wrap must have a suitable bursting strength and a tear resistance of at least 1200 mN, preferably even higher. Similarly, the adhesiveness of the glue should be at least 15 Dennisons or greater.

Figures 9-12 show different kinds of carry handle solutions for the group package 1 according to the invention. Although the group package can be lifted using two hands at the ends of the package as described above, sometimes it is easier to handle the package using purpose-made carry handles. Sometimes it is also necessary to handle the package with just one hand.

Figure 9 shows a group package 1 according to the invention, with a separate carry handle 13 at each end of the package. The strip-shaped, suitably enforced carry handle 13 is glued at each end of the package in between the outer folds 3 and 4 and the inner folds 5 and 6.

Similarly, Figure 10 shows a group package 1 according to the invention, with a separate carry handle 14 at the top of the package. The carry handle 14 is made for example out of fibre-reinforced paper laminate, and glued at the ends to each end of the group package 1, for example so that the glue seam is placed between the inside of the handle and all of the package's end folds 3-6. In addition, the carry handle 14 can be glued along a short distance to the top of the group package 1 at the ends of the package. This creates a durable and easy-to-use carry handle solution.

Figure 11 shows a similar handle solution to that in Figure 10, but in this embodiment a strip-shaped carry handle 15 is placed crosswise across the group package 1 and glued at the ends to the sides of the package. For increased durability, the carry handle 15 can be glued along a short distance to the wrap at the top of the package, starting from the upper edges of the package.

The carry handles 14, 15 described in Figures 10 and 11 can also be made to surround the whole group package 1, being glued for example at the bottom of the package so that the handle will not disappear. In such a case the carry handle also supports the load, which means that the wrapping that forms the protective wrap 2 can be thinner than that used in solutions where the handle is glued to the wrap or ones where the package is lifted by the wrap's end folds.

Figure 12 shows a carry handle solution in which a strip- shaped handle 16 is placed crosswise across the group package 1 and glued at the ends to the top of the package. The attachments are strengthened with a reinforcement tag 17, which tag has a hole in the middle for the carry handle 16 to pass through. The reinforcement tag 17 is glued to the top of the group package so that it covers the ends of the carry handle 16.

Those skilled in the art will see that the invention is not limited to the example given above, but can be varied within the scope of the patent claims given below. Thus the protective wrap does not have to come off a reel for the production of the group package, but can be in ready-cut sheets. Further, those skilled in the art will see that the wrapping of the protective wrap around the group package can be done in many different ways, as can the gluing of the folds at the ends of the package.

Those skilled in the art will also see that various different carry handles from those presented above can be attached to the group package according to the invention. The whole group package can for example be surrounded by a separate reinforced paper band that is used similarly to the plastic strips that are commonly applied. The width of the paper band makes the group package more pleasant to handle, however. In this solution, the protective wrap can be thinner and weaker than in the abovementioned solutions, because the wrap itself does not bear any load when the group package is lifted or carried. The carry handle can be paper and/or plastic.

Further, those skilled in the art will see that instead of a wrap, other kinds of protective structures than those mentioned above can be used. For example wraps consisting of nonwoven fabric or other similar thin protective materials can be used in the solution according to the invention.

Further, those skilled in the art will see that the group package according to the invention is suitable for many other package types than a group package for five separate paper bundles. There can be for instance 2-5 paper bundles that are wrapped together into one group package.

Those skilled in the art will also see that the thicknesses and weights of the papers used for the protective wrap can differ from those listed above.

Further, it is evident to those skilled in the art that instead of a paper-based protective wrap, the group package can consist of a protective wrap made out of corrugated board or a similar material. In this case the water vapour transmission rate must also be chosen so that the protective wrap and the paper bundles' wraps added together form a suitable barrier.

Those skilled in the art will also see that the wrapping materials do not have to contain any plastic, if substances that make the material sufficiently hydrophobic are added for example to the base paper layer at the time of the paper's production.

Those skilled in the art will also see that the paper sheets can be wrapped in more protective layers than the abovementioned two layers formed by the paper bundles' wraps and the group package's protective wrap or box. There can be for example three, four or more protective layers. A single protective layer is enough if its strength and water repellence are good enough.

Claims

PATENT CLAIMS

1. A group package (1) for sheet material such as printing and photocopy paper, in which group package (1) a number of paper bundles (Ia) wrapped in their own wrap (2a) consisting at least of a base paper layer (19a) , are placed inside a shared protective wrap (2), and in which plastic, a polymer mixture or another suitable material that slows down the penetration of moisture is added at least to the base paper layer (19a) of the wrap (2a) , characterised in that the material of the protective wrap (2) and the material of the wrap (2a) used for the paper bundles (Ia) is formed by adding plastic, polymer mixture or another suitable material to both wrap materials such quantities that the water vapour transmission rate (WVTR) of the protective wrap (2) and the wrap (2a) in common is less than approximately 50 g/m²/d, as calculated according to the ISO 2528:1995 standard.

2. A group package (1) for sheet material such as printing and photocopy paper, in which group package (1) a number of paper bundles (Ia) wrapped in their own wrap (2a) consisting at least of a base paper layer (19a) , are placed inside a shared protective wrap (2) , consisting at least of a base paper layer (19), in which package plastic, a polymer mixture or another suitable material that slows down the penetration of moisture is added at least to the base paper layer (19a) of the wrap (2a) , characterised in that the material of the protective wrap (2) and the material of the wrap (2a) used for the paper bundles (Ia) are formed by adding plastic, polymer mixture or another suitable material to both wrap materials' base paper layers (19, 19a) such quantities that the water vapour transmission rate (WVTR) of the protective wrap (2) and the wrap (2a) in common is less than approximately 50 g/m²/d, as calculated according to the ISO 2528:1995 standard.

3. A group package (1) according to claims 1 or 2, characterised in that the total water vapour transmission rate of the protective wrap (2) and the wrap (2a) , as calculated according to the ISO 2528:1995 standard, is a maximum of approx. 30 g/m²/d and favourably a maximum of approximately 10 g/m²/d.

4. A group package (1) according to claims 1, 2 or 3, characterised in that the protective wrap (2) and the wrap (2a) contain a maximum of approximately five per cent of their own total weight in plastic.

5. A group package (1) according to claims 2, 3 or 4, characterised in that the protective wrap (2) consists of an essentially similar, paper-like and pliable wrapping to that of the wraps (2a) of the paper bundles (Ia) .

β. A group package (1) according to any of the claims above, characterised in that plastic, a polymer mixture or another similar material that slows down the penetration of moisture is added at least to the wrap (2a) of the paper bundles (Ia) using the online method during the production of the wrap (2a) in a paper machine.

7. A group package (1) according to any of the claims 2-6 above, characterised in that the wrapping that forms the group package's (1) protective wrap (2) is taken directly from a reel and wrapped at least once around the long sides of the group package (1) , and that on the inner surface of the protective wrap, at least close to one end of the group package (1) , there is an opening strip (23) , essentially the same length as the protective wrap and placed lengthwise along the protective wrap.

8. A group package (1) according to any of the claims 2-7 above, characterised in that at the ends of the group package (1), the edges of the protective wrap of the package are folded creating folds (3-6) so that at least one outer fold (3, 4) is attached to one inner fold (5, 6) .

9. A group package (1) according to any of the claims 2-8 above, characterised in that a lifting gap (7) is formed between the outer folds (3, 4) and the inner folds (5, 6), and in that the lower edges of the outer folds (3, 4) are designed to work as lifting supports.

10. A group package (1) according to any of the claims above, characterised in that at least one separate carry handle (13, 14, 15, 16) is attached to the protective wrap (2) of the group package (1) .

11. A method for producing the protective wrap (2) for a group package (1) of sheet material such as printing and photocopy paper, and/or the wraps (2a) for the paper bundles

(Ia) to be packed in the group package (1) , characterised in that in producing the material of the protective wrap (2) and/or the material of the wrap (2a) , plastic, a polymer mixture or another suitable material is added to the base paper layer (19, 19a) of the material using online technology in a paper machine, in suitable quantities to make the combined water vapour transmission rate (WVTR) of the protective wrap (2) and the wrap (2a) of the finished group package (1) less than approx. 50 g/m²/d, as calculated according to the ISO 2528:1995 standard.

12. A method according to claim 11, characterised in that in producing the material of the protective wrap (2) and/or the material of the wrap (2a) , plastic, a polymer mixture or another suitable material is added to the base paper layer

(19, 19a) of the material using online technology in a paper machine, in suitable quantities to make the combined water vapour transmission rate (WVTR) of the protective wrap (2) and the wrap (2a) of the finished group package (1) a maximum of approx. 30 g/m²/d, favourably a maximum of approx. 10 g/m²/d.

13. A method according to claims 11 or 12, characterised in that in producing the material of the protective wrap (2) and/or the material of the wrap (2a) , plastic, a polymer mixture or another suitable material is added to the base paper layer (19, 19a) of the material using online technology in a paper machine, in suitable quantities that the materials (2, 2a) contain a maximum of approx. five per cent of their own total weight in plastic.

14. A method according to any of the claims 11-13 above, characterised in that the group package is formed out of essentially strong and durable reel-based wrapping material, which is cut into the correct length at the beginning of the packaging process and which forms the protective wrap (2) , which is placed centrally along its width on top of the paper bundles to be packed, and in that an initial wrapping is done by wrapping the protective wrap around the office paper bundles (Ia), after which the wrap's end folds are formed by pressing the inner folds (5, 6) against the end of the group package (1), formed by the end surfaces of the paper bundles, and the outer folds (3, 4) are formed by folding the parts of the protective wrap that exceed the length of the paper bundles at the vertical ends to form essentially two triangular folds, and that after the folds are made, the outer folds (3, 4) are attached at the ends of the group package (1) at least to one of the inner folds (5, 6) and, if necessary, also to each other.

15. A method according to claim 14, characterised in that the group package (1) is produced out of reel-based, essentially strong and durable wrapping material that forms a protective wrap (2) , which wrapping material is wrapped directly off the reel around the office paper, and in that the folds (3, 4) at the ends of the group package form supports that act as carry handles .