HRP20010157A2 - Packaging wrapper - Google Patents

Description

This invention relates to a wrapping package, suitable for use with an article to be wrapped, consisting of a film that can be cut into special sheets intended for closure by folding around the article to be wrapped.

Without being limited thereto, this invention particularly relates to the field of wrapping confectionery and chocolate products or other food items such as, for example, soup cubes.

Generally, the articles are individually wrapped in pre-printed rectangular film of the appropriate size and shape, and the individually wrapped articles can then be bulk packed into a bag of the appropriate size. The article to be wrapped, which is, for example, parallelepipedal in shape, is placed, according to the usual method of wrapping, in the middle of the reverse side, that is, the unprinted side of the rectangular sheet. Then the two longitudinal sides are folded up (or down, depending on the position of the article and the type of wrapping machine), perpendicular to the longitudinal sides of the article. After that, the sides are folded vertically upwards along the two transverse sides of the article and their upper edges are folded flat over the upper side of the article, with the fact that these two last operations are certainly carried out through gradual and curved folding operations with the longitudinal sides already raised up. Wrapping is completed by folding the upper edges (which in the meantime have taken the form of trapezoidal tops) of the longitudinal sides, one over the other, over the upper side of the article.

It should be noted, however, that depending on the shape of the product being wrapped and the nature of the wrapping machine, another folding sequence of the wrapping sheets is also possible, with this folding sequence taking place in a precise configuration of the folding lines. That configuration of the fold lines of the wrapping sheets always remains the same for the same article to be wrapped using the same wrapping method.

Here there is a significant problem of holding the folded pages at the end of the wrapping operation so that the wrapper remains closed. This can be ensured only at the expense of a specially selected film used as the bottom layer, which must have appropriate mechanical properties such as flexibility and, in particular, a pronounced tendency not to return to its initial position after folding the sheets during wrapping.

This problem is particularly expressed when wrapping small-sized articles such as confectionery products such as sweets, pralines, lollipops, sugar sticks, chocolate-covered sticks, etc. or such as soup cubes.

One of the known solutions is the selection of special backing layers that are known for their flexibility, such as wax paper, cellophane, aluminum laminates or alternatively synthetic films that contain an appropriate amount of additives that increase the flexibility of this backing layer.

This solution, however, rather narrows the possible choice of films used as wrapping paper substrates or significantly increases their cost.

There are also known materials for wrapping certain articles, such as soup cubes, in which the wrapping film is closed by joining. For this purpose, the wrapping sheets on their right side, i.e. the side that is on the outside of the article to be wrapped, are coated with a structure for hot glue, which is adapted in configuration to match the configuration of the folds that occur during wrapping.

The disadvantage of this wrapping process is that the wrapping machine must be specially adapted to this process in the sense that it must have a heat source. In addition, if this heat source consists of heating plates, the joining can only be achieved on perfectly flat surfaces of the article being wrapped and, in addition to the time required for welding, requires a relatively high pressure that a certain number of products are not able to withstand.

Another disadvantage is that this wrapping process is completely unsuitable for wrapping articles that are sensitive to heat, especially chocolate products, and does not allow the selection of a wrapping substrate that is resistant to low temperatures.

Patent application EP-0,870,695 proposes a wrapping sheet for closing by folding around an article, the right side of which, i.e. the side that will be on the outside of the article, is coated with a cold adhesive structure arranged in such a configuration that the adhesive coated areas are on top when the sheet is wrapped around the article. These glue-coated areas secure the folded parts when the wrapping material has the peculiarity of not securing the folded ends well. These sheets, however, are coated with a thermal adhesive varnish that keeps the package closed and has the above-mentioned disadvantage. This sheet also has the disadvantage that the reverse side must have non-adhesive strips in order for the film to be unwound from the roll.

Document EP 0 225 987 describes a wrapping film which has on its right side and on its wrong side areas covered with cold adhesive coatings, in particular two longitudinal strips, one on the right side and one on the reverse side. In order for this film to be stored in the form of a roll, these different adhesive areas must be arranged in such a way that they do not come on top of each other when winding on the roller, because such a superposition could cause these different areas to stick to each other and thus make it impossible to unwind the film with roller. However, this limitation related to the layout of the adhesive rollers. However, this limitation on the arrangement of the adhesive regions entails corresponding limitations on the folding configuration and on the wrapping process.

In fact, the two documents mentioned above have the same objective, that is to enable the adhesive areas on the film to hold the folded ends and to arrange them in such a way that the film can be stored in a rolled state. The problem is actually, as described here below, that if the film has self-adhesive areas on the reverse side and on the right side, then when winding the film onto the roller, some of these adhesive areas are at risk of being on top of each other on the roller and stick to each other, which would make it impossible to unroll the film from the roller.

These two documents seek to solve this problem using different means. Document EP-0 870 695 offers areas with cold adhesive coatings only on the right side. That's why there is no danger of mutual superposition during winding. In contrast, in order to enable a solution to the problem of fixing the folded ends, this document provides for a thermal bonding varnish on the reverse side, which leads to the aforementioned disadvantages.

Document EP-0 225 987, on the contrary, opts for a special arrangement of the areas with the cold bonding coating on the reverse side with respect to that on the right side or vice versa, so that during winding the coatings of two touching turns are arranged next to each other and not superposition occurs. This solution, however, dictates limitations on the wrapping process inasmuch as the folding configuration must be designed according to the location of the adhesive areas, when exactly the opposite is desired.

Therefore, the object of this invention is to offer a new packaging that enables a much wider choice of film to be used and to enable the film to be stored on the roll without any restrictions regarding the wrapping method.

In order to achieve this goal, the present invention provides a wrapping package according to Claim 1.

The applicant company suddenly discovered that at least partially pre-coating the film used as wrapping packaging with a specific cold adhesive coating allows, once the wrapping sheet is closed by folding, to obtain folds that can be very strong, and also allows the film to be stored on roller.

The fact is that the substance used as an adhesive coating hardly or not at all adheres to a smooth surface or to a surface treated for this purpose, but that, on the contrary, it exhibits good adhesion when applied to itself, which occurs during folding. The folds are therefore simply fixed by applying light pressure and mutual superposition of certain areas coated with cold glue, and this can be achieved without any other aids than those required for folding the envelope.

According to the present invention, cold bonding means bonding that occurs immediately by simple contact at a temperature between approximately 0 and 50ºC. In fact, temperature is not a critical parameter for gluing using a cold gluing coating and has practically no effect on the quality of the gluing achieved. Therefore, gluing can be achieved without the need to apply additional heat, at the temperature of the room where the wrapping unit is located.

In fact, until now, cold bonding coatings were used primarily in layers on a substrate that shows little or no deformation. This means that with any application of this cold bond coating on a substrate that is not completely flat, major blocking problems can be expected due to the self-adhesive properties of the cold bond coating.

That is why the present invention enables the use of films that are cheaper and show better properties (strength, possibility of printing on them, aesthetic appearance) for wrapping articles, without any restrictions regarding the shape of said articles.

With regard to the application of rigid films, it will be noted that the use of rigid films for packaging to be glued by folding has hitherto been avoided. The reason for this is that these rigid films have a very low ability to hold the flap in place.

In relation to the problem of storing the film on the roll and compared to the solutions recommended in the two documents illustrating the state of the art, the existing application provides a completely different solution that was considered impossible until now, which consists in tolerating the mutual superposition of certain adhesive areas when the film is stored on roller. To this end, the present invention contemplates the selection of a precise cold bonding coating that possesses what the application calls "controlled adhesion," that is, adhesion that is strong enough for the required needs, but not strong enough to resist re-peeling. Thus, the film can be unwound from the roller several times without excessive resistance, even in the case of the innermost revolutions, where the tension is normally higher. This solution certainly offers considerable advantages over the solutions offered in the previously mentioned documents insofar as the same glue (and therefore not hot glue) can be applied everywhere and that the adhesive areas can be obtained at the desired points depending on the shape of the product to be wrapped and the wrapping sequence .

According to a more favorable embodiment, the structure of the adhesive coated areas consists of, on the right side, two W-shaped strip structures along two opposite sides of the wrapping sheet, one strip along the third side of the sheet and between the two W-shaped structures, and two areas on two corners on the fourth side of the arch.

Tapes with an adhesive coating stacked according to the folding configuration can have a row width of 4 mm.

The configuration of the structure of the tape with an adhesive coating can have varying shapes depending on the article to be wrapped and the folding sequence.

In addition to the strip structure along the future folds, each film has an adhesive coating along the length of one edge of the third side. This tape will be on the tip, which, at the end of the wrapping process, will be the first to be folded over the base of the article being wrapped and will adhere to the tip which will be the last to be folded. Each wrapping sheet may also have special areas of adhesive coating which enable the last overlapping tip to adhere to the base of the wrapped article and thus play its part in tightly sealing the wrap.

According to one aspect of the present invention, the bonding achieved by the mutual superposition of the cold bonding coating strips is not irreversible, as it must allow the film to be unrolled when it is packed and wrapped around the roller, without the risk of tearing the film. In other words, it is necessary to choose an adhesive coating that corresponds to the nature of the substrate on which it is applied, so that, on the one hand, it will adhere to itself weakly enough to allow the film to be unrolled from the roller and, on the other hand, strong enough to allow an almost hermetic closure packaging. One could talk about controlled adhesion here. The advantage of this controlled adhesion is also that the packaging can be opened and closed again several times without a significant reduction in the quality of adhesion.

As mentioned earlier, one of the good sides of this invention is that it allows the application of a wide range of possibilities with regard to the nature of the substrate being used. Examples of suitable films are plastic films with a thickness of about 10 to 100 microns made of extruded and oriented polypropylene, of formed polypropylene, of polyester, of polyethylene, of extruded and oriented polyamide or of formed polyamide.

In accordance with the present invention, it is also possible to use a paper substrate (glossy or coated). In general, any backing material or flexible wrapping material may be suitable as a backing according to the present invention. These different substrates can consist of only one layer, of a metallized single layer or of several laminated and/or coextruded layers.

The general rule is that pressure-sensitive adhesives are mixtures based on natural and/or synthetic rubber combined with modified cellophanes, phenolformaldehyde resins or hydrocarbon resins (waxes). In addition to rubber, it is possible to use polymers based on styrene, (meth)acrylic acid or vinyl ether, alone or in combination, and also in combination with resins. Finally, the use of silicone resins is also possible. It is best to apply mixtures containing mixtures of natural and synthetic rubbers and copolymers of (meth)acrylic acid and styrene.

In accordance with the present invention, cold adhesive coatings are applied to substrates in amounts of approximately 1 to 5 g/m2.

Cold adhesive coatings can be applied in the form of a solution, spray or even in a molten state.

Other significant features and properties of this invention will become apparent from the detailed description of a series of embodiments in the remainder of this text, with the help of illustrations, with reference to the attached drawings, where:

Figure 1 shows the right side embodiment of the wrapping sheet;

Figures 2 to 8 illustrate a sequential sequence of one example of candy wrapping using the sheets of Figure 1;

Figure 10 shows the right side of the embodiment of Figure 1 replaced by an adhesive structure on the reverse side;

Figure 11 shows a cross-section, on a larger scale, through one example of the design according to Figure 10, and

Figure 12 shows a simplified alternative form of the embodiment shown in Figure 10.

Fig. 1 depicts the real side, or printed side, of the wrapping sheet 20 after the sheet has been cut from the film unwound from the roll (not shown) in the direction indicated by arrow A in the figure.

A cold adhesive coating is applied to the structure 22 which is adapted to match the configuration of the fold lines during wrapping, an example of which will be described later; in the case of Fig. 1 there are two strip structures 24, 26, row width ± 4 mm, roughly W-shaped, along two opposite sides of the sheet 20, and a strip 28 along the third side between the two lateral W-shaped structures. the one on which the strip 28 is located, there are also, in the corner areas, two coatings with a cold adhesive coating 30 and 32. Compared to the original film on the roll, the strips 24, 26 are located along the longitudinal edges, while the strip 28 is transverse. On the roller, these different strips of adhesive coating are located on the outside of the roller spin.

Sheet 20 in Figure 1 can be prepared by placing a thin printed layer or finish (for example, product 10-612205-4 MX41 from SIEGWERCK) on the right side of a 25 micron thick oriented polypropylene film, which may or may not be metallized, in order to improve adhesion of printing ink. The film is then printed using techniques known per se, such as, for example, heliographic or flexographic printing or alternatively offset printing. A protective varnish known per se is placed over the print. Cold adhesive coating structures 22 are then applied to this varnish, according to the pattern shown in Figure 1. This application can also be carried out using printing techniques known per se.

The product IP7905 or IP7936 from the SWALE company can be used as a cold adhesive coating, which will be applied, for example, in an amount of 3 g/m2. It is an adhesive coating that sticks to itself. In other words, this coating does not adhere to the untreated smooth reverse side of the film, which allows the film to be easily stored and packaged in roll form without any problems when unwinding from the roll. This adhesive coating also has the property of having a low coefficient of friction (COF) to metal, which is of the order of 0.2 to 0.6, while the usual COF to metal is of the order of 1 to 1.5. Such a low coefficient of friction reduces the risk of jamming and sticking to the box.

The operation of wrapping an approximately parallelepiped shaped candy using the sheet 20 of Figure 1 will now be described with reference to Figures 2 through 8. The sheet is placed over the candy with the reverse or raw side facing the candy so that the strip 28 and the opposite side with the adhesive areas 30 and 32 are in in the longitudinal direction of the candy, and W-shaped structures in the transverse direction of the candy. The sides of the ark 20 are then folded down over the longitudinal sides of the alktis, as shown in Figure 2.

The next operation consists of folding the middle part of each side of the sheets with structures 24 and 26 down over the side surfaces of the candy 34, as shown in Figure 3. This operation is performed by folding the longitudinal sides of the sheets 20 over the diagonal fold lines 36 and 38. As visible in Figure 3, the two W-shaped structures 24 and 26 (26 is not visible in Figure 3) of the adhesive coating are stacked so that the two outer arms of the W-shaped structures go along the fold lines 36, 38 and that the inner part in the form of letter V fits the transverse side of candy 34.

The operation that follows consists of folding down, on each side of the candy 34, the two folds bounded by the fold lines 36 and 38 inwardly in the direction of arrows 1 and 2 in Figure 3. By this operation, the outer strips of the W-shaped structure of the adhesive coating, that ie the strips running along the fold lines 36 and 38, are placed over the inner V-shaped strips, resulting in the configuration shown in Figure 4. This folding sequence is apparently the same on both longitudinal sides of the candy. Given that all the strips of the two W-shaped structures 24 and 26 are completely superimposed and that the applied cold adhesive coating adheres perfectly to itself, the configuration in Figure 4 represents a stable configuration and perfectly secures the flaps made so far.

The next folding sequence is shown in Figure 5, and consists in folding the lower parts of the previously folded and downwardly folded side flaps to the bottom side of the candy 34. This operation is performed by folding the longitudinal sides along the diagonal folding lines 40, 42, 44, 46, which the longitudinal sides turn into trapezoidal peaks 48, 50. The result of this folding can be clearly seen in Figure 6, which shows the appearance from the bottom side and from the side that was not visible in the previous pictures.

It should also be noted here that the two cold-adhesive coating regions 30 and 32 are folded in such a way that their inner beveled edges (see also Fig. 1) run along the fold lines 40 and 42 of the tip 48, as seen in Fig. 6.

Figures 7 and 8 show the last stages of wrapping. First, the tip 50, on which the adhesive coating strip 28 is located, is folded down to the inside as shown in Figure 7. Then, the other tip 48 is folded down to the tip 50 to achieve the configuration in Figure 8.

When the tip 48 is folded down, the two adhesive coated areas 30 and 32 are partially positioned one above the other and partially attached to the adhesive tape 28 of the tip 50. As a result, since the tip 48 adheres to itself and to the tip 50, the configuration with Figure 8 shows a stable configuration with all flaps firmly secured in place.

However, it should be noted that when the tip 48 is folded down onto the tip 50, the adhesive strip 28 adheres only at its ends to the adhesive areas 30 and 32. They are opposite each other, and its center will contact the reverse side of the tip 48, to which it will not stick. In other words, while the ark of Figure 1 provides packaging that closes tightly and permanently, it does not allow for hermetic closure.

All wrapping sequences described below are performed automatically by the wrapping machine. In this context, it is important to note that the proposed wrapping sheets are suitable for existing wrapping machines without any need for modification or adaptation. However, it should be noted that the envelope described below is only one example of a particular machine's folding configuration. Other machines can perform folding operations according to different configurations of folding lines. As is the case here, the pattern of adhesive structures in Figure 1 will have to be adjusted to match the configuration of the fold lines produced by the folding machine, as the reverse is more difficult to do.

Figure 10 shows a more convenient embodiment of the wrapping sheet according to the present invention and generally indicated by the numeral 56.

And again, oriented propylene film can be used, which is printed as needed, preferably after applying the base layer. Next, non-stick coating 60 is applied to the entire right side. Suitable non-stick products consisting of mixtures of polyamide resin and polyethylene wax (for example, products 10-609345-3P from SIEGWERCK and 994404-X from SICPA) are applied in an amount of 1, 5 g/m2. Patterns 22 of cold tack similar to those in Figure 1 are then applied to this layer. Then, a strip of dry-type cold tack is applied to the reverse side, more or less between areas 30 and 32 of the real side, as shown by dashed lines at 58. When the sheet 56 is used for wrapping as described in Figures 2 through 8, the adhesive tape 58 at the end of the wrapping operation (see Figure 7) will be on the inside of the tip 48 and, when that tip is folded, will adhere to the adhesive tape 28 of the tip 50 so that the end result would be a practically hermetically sealed envelope.

When the film according to Figure 10 is stored in the form of a roll, the adhesive strips 58 on the reverse side are completely in contact with the non-adhesive spread 60 on the right side, to which they do not adhere. However, as the unwinding progresses, and after a certain number of unwindings, the strips 58 will come into contact with the adhesive strips 28. Then, due to the selection of the nature of the adhesive of the strips 28 and 58 and their controlled adhesion, it will also be possible to peel and unwind the film from the roller, without causing the film to move and without significantly reducing the adhesive properties of tapes 28 and 58.

Instead of laying strips of adhesive spread in a generally rectangular shape, as shown in the pictures, it is possible to make oval bindings. This allows gradual separation, with less risk of tearing when opening the wrapper or when unrolling the filling from the roller.

Figure 11 is a cross-section, in an enlarged ratio, through the thickness of an example sheet of the embodiment as in Figure 10. In this favorable embodiment, there are different layers, labeled A - F, with A being the real side and F being the reverse side:

A: adhesive spread based on latex, applied in quantities of 2-4 g/m2, product IP 7985 of SWALE company,

B: PVB (polyvinylbutynal) varnish, product WO 48825 of the SWALE company with wax additives and non-stick properties for coating layer F, and applied in quantities of 0.7 - 1.3 g/m2,

C: color printing using PVB ink, Dynavin series, manufactured by SWALE and applied in an amount of 2-3 g/m2,

D: water base layer, type 200970 produced by SWALE, applied in amounts of 0.4 - 0.8 g/m2,

E: co-extruded oriented propylene film type BEZ, supplier VIBAC, 30 μ thick and composed of:

E1: metallization layer with a thickness of 0.2 - 0.4 μ

E2: 1.5 μ thick co-extruded layer consisting of a mixture of copolymers and homopolymers

E3: homopolymeric cores with a thickness of 27 μ

E4: homopolymeric coextruded layer with non-adhesive properties for layer A,

F: cold adhesive latex-based spread, applied in quantities of 2 - 4 g/m2, product IP 7983 of the SWALE company.

The resulting film can be unwound and wrapped up to 10 times on a roller without losing the adhesive properties necessary to create a tightly closed wrap.

Figure 12 shows a simplified alternative form of the embodiment of Figure 10. In this alternative form, the sheet 62 simply has, on the reverse side, along one of the edges (transverse edge with respect to the film on the roll before cutting), a tape 64 with a cold adhesive coating corresponding to strip 58 of Figure 10 and, along the opposite side, on the right side, another strip 66 with cold adhesive, which corresponds to strip 28 of Figure 10. The construction of the film can be as described above with reference to Figure 11. Two strips 64 and 65 are shown, by way of illustration, and as mentioned earlier, in an oval shape, for easy separation when unrolling from the roller.

In other words, in this alternative form of Figure 10, the structure 24, 26, 30, 32 of the adhesive coating of Figure 10 is not used. This alternative form can be applied when the practically hermetic closure allowed by the embodiment of Figure 10 is not required and when the closure along the fold lines not glued. In contrast, the final wrapping stage consisting of the superimposition of the adhesive regions 64 and 66 enables the previously performed folds to be held in place when the wrapping is performed by a box-folding type machine, i.e. when all the folds mentioned in connection with Figures 3 to 6 are performed. practically at the same time.

Claims (4)

1. Packaging for wrapping, intended for packaging an article (34), especially a food product, with the fact that this packaging is obtained from a film that is kept wound, in the longitudinal direction, on a roller and that can be cut transversely into special sheets (56, 62 ) intended for closing by folding around the article (34), indicated by the fact that on this film there is, on each sheet (56, 62), along its transverse edge, a strip of cold adhesive spread (28), (58), (64), ( 66), with the fact that one of the strips (28), (66) is on the right side, and the other (58), (64) on the reverse side of the film, with the said strips (28), (58), (64 ), (66) by mutual superposition after the last stage of folding, they keep the packaging finally closed and by the fact that the mutual adhesion of said strips (28), (58), (64), (66) is a controlled adhesion that is strong enough to keep the envelope closed but not enough it greatly interferes with the unwinding of the film from its roller when there is mutual contact, in the wrapped state of the roll, between the tape (28), (66) for example this side and strips (58), (64) on the reverse side. 2. Packaging according to Claim 1, characterized in that on the right side of each sheet there are areas with cold adhesive coatings (22) at least partially distributed along three sides of the periphery of the sheet (56) in such a configuration that most of these adhesive coated areas are superimposed when the sheet is wrapped around the article, blinding and holding the flaps in place around said article. 3. Packaging according to any one of Claims 1 and 2, indicated by the fact that the adhesive spread of the strips (58), (64) of the adhesive spread on the right side is applied in the form of an oval strip. 4. Packaging according to any of Claims 1 to 3, characterized by the fact that on each sheet (56), (62) there is, over the entire right side, a non-sticky spread (60) which is applied before the sticky spread of the area with cold sticky spread