HK1040227A1 - Packaging wrapper - Google Patents

Abstract

The confectionery packaging has a separable film with detachable sections (20) to enclose the article (34). At least rear face of a film section is coated for cold sealing (22) at least partially around the periphery of the film. The larger parts of the sealed zones are superposed after folding to mutually adhere.

Description

Packaging material

The present invention relates to a packaging material for use with an article to be packaged, which packaging material is formed from a film that can be cut into individual packaging pieces for wrapping around the article to be packaged by folding.

Without being limited thereto, the invention also relates in particular to the field of packaging of confectionery and chocolate products and other consumer products, such as soup solids.

Typically, the articles are individually wrapped in a pre-printed rectangular film of appropriate shape and size, and the individually wrapped articles are then weight packed in a suitably sized bag. According to one common packaging method, the article to be packaged, for example in the shape of a parallelepiped, is placed in the centre of the opposite, i.e. unprinted, face of a rectangular packaging sheet. The two longitudinal faces are then raised vertically (or depressed depending on the orientation of the article and the type of packaging machine) so as to face the longitudinal faces of the article. The two transverse faces are then raised vertically so as to face the transverse faces of the article and the upper edges of these faces are flattened on the upper bottom of the article, this two-part operation being carried out by successive oblique folding of the previously raised longitudinal faces. By pressing the upper edges of the longitudinal faces, which in this case are trapezoidal tongues, one against the other against the upper surface of the article.

It should be noted, however, that other folding sequences of the packaging sheet are possible, depending on the shape of the product to be packaged and on the nature of the packaging machine, these folding sequences being carried out according to the arrangement of the folding lines already determined. The arrangement of the fold lines of the wrapping sheet is always the same for the same articles wrapped in the same wrapping method.

An important problem posed here is that of maintaining the fold at the end of the packaging operation, in order to bring the package into a closed condition. The folding is only ensured by the particular choice of film used, the substrate of which should have suitable mechanical properties, such as foldability, in particular without a significant tendency to return to its original position after folding of the packaging sheet during packaging.

This problem is particularly manifested when packaging small-sized articles such as confectionery products, e.g. candies, sugar coated almonds, lollipops, maltose, chocolate bars and the like, or solid soup bases.

Known solutions are to select a particular substrate with good folding properties, such as waxed paper, cellophane, aluminium foil or synthetic films containing a certain amount of additives that improve the folding properties of the substrate.

However, this approach greatly limits the possibilities of selecting films for use as packaging materials, or greatly increases the cost.

It is also known that the packing closure of certain articles, such as packed sheets of soup solids, is ensured by gluing. The front side of the packaging sheet, i.e. the outer side of the articles to be packaged, therefore comprises a structure of heat-seal coating, the arrangement of which is adapted to the folding arrangement to be achieved during packaging.

A disadvantage of this packaging method is that the packaging machine must be specially adapted to this method, requiring a heat source. In addition, if the heat source consists of heating plates, the adhesion can only be carried out on a perfectly flat surface of the article to be packaged and, in addition to the time required for welding, a relatively large pressure is required, which some products cannot withstand.

Another disadvantage is that this packaging method is not at all suitable for packaging items sensitive to heat, in particular chocolate products, and does not allow the selection of a packaging substrate resistant to temperature differences.

Patent application EP-0870695 proposes a packaging sheet closed by folding around the article, the front side of which, i.e. the surface located on the outside of the article, has a structure of a cold seal coating, the arrangement of which is such that the regions of the seal coating overlap one another by folding the packaging sheet around the article. These seal coating areas thus ensure that the fold is maintained when the material of the packaging sheet does not have fold-maintaining properties. However, such packaging sheets are provided with a layer of heat-adhesive lacquer, which keeps the packaging sheet closed and has the above-mentioned disadvantages. In addition, the packaging sheet has the disadvantage that the reverse side should have some anti-adhesive tape in order to be able to unwind a roll of film.

The object of the present invention is to propose a new packaging material which allows a wide selection of films to be used and which allows the films to be stored in rolls.

To achieve this object, the invention proposes a packaging material for packaging articles, in particular food products, consisting of a film stored in a roll, which can be cut transversely into individual packaging webs folded around the articles to be closed, characterized in that each packaging web of the film has a band of cold-seal coating at least along the transverse edge of the packaging web, ensuring a controlled adhesion of the packaging web to itself and a sufficiently strong adhesion to maintain the package closed, but not so strong as to hinder the unwinding of the film roll.

The film preferably has a cold seal coating band on each packaging sheet along each transverse edge, one coating band on the front side of the packaging sheet and the other on the back side of the packaging sheet.

The applicant has surprisingly found that at least partial pre-coating of the film used in the packaging material with a defined cold seal coating allows good fold retention properties of the packaging sheet after folding closed and also allows the film to be packaged in rolls.

The fact is that the substances used as sealing coatings have little or no adhesion on smooth surfaces or surfaces treated therewith, but on the contrary have good adhesion when applied to the coating itself, as is the case when folded. The retention of the fold is thus ensured simply by a slight pressure and the mutual overlapping of some of the sealing coating areas, without the need for additional attachment means other than those required for the folding of the package.

According to the invention, cold sealing is a sealing which is accomplished immediately by simple contact at a temperature of 0-50 ℃. In practical cases, temperature is not a critical parameter for the seal obtained with a cold seal coating, nor does it actually affect the quality of the seal. The sealing does not need to provide supplementary heat and can be performed at the ambient temperature of the space in which the packaging unit is located.

Indeed, to date, cold seal coatings have been layered on substrates with little or no distortion. In fact, it may be expected that the use of cold seal coatings on an uneven substrate can cause serious clogging problems due to the self-adhesive properties of the cold seal coating.

Therefore, the present invention can package an article using a film which is less expensive and has better properties (hardness, printability, aesthetic properties) without limitation to the shape of the article.

With regard to the use of rigid films, it is pointed out that, up to now, the use of rigid films has always been avoided with packages that need to be closed by folding. In fact, the ability of these stiff films to remain folded is very low.

When preparing a roll of film for packaging, one surface of the film is covered with a seal coating and an anti-seal coating can be applied to the other surface to prevent adhesion from contact between the surface covering the seal coating and the other surface when the film is rolled. However, it is noted that there is a so-called "dry" cold seal coating, which is not required when used with certain substrates such as polypropylene films. Both methods may also be used within the scope of the present invention.

According to an advantageous embodiment, the structure of the sealing coating zone comprises two W-shaped band structures along opposite sides of the packaging sheet, one band along the third side of the packaging sheet and between the two W-shaped structures, and two zones in two corners of the fourth side of the packaging sheet.

The width of the sealing coating band distributed according to the folding position may be about 4 mm.

The arrangement of the closure coating band structure may take a variety of different forms depending on the article to be packaged and the folding sequence.

In addition to the tape structure along the fold to be effected, each packaging sheet may have a band of closure coating along the edges of the three sides of the third strip. The strip is placed on a tongue which, at the end of the packaging process, is first pressed against the bottom surface of the article to be packaged and ensures adhesion to the last folded tongue. In addition, each packaging sheet of the packaging film includes additional regions of a seal coating that can adhere to the tongue that is ultimately pressed against the bottom surface of the packaged article, thus helping to maintain the package in a closed condition.

According to another embodiment, a band of cold seal coating, called "soft", can be provided along the edge of the last pressing tongue at the end of the packaging operation. Such a coating, in contrast to the dry coating discussed above, may be adhered to the smooth surface of the reverse side of the packaging sheet. Such a soft sealing coating ensures a good adhesion between the two longitudinal tongues folded over at the end of the packaging operation, so that a sealed package is achieved, improved preservation of the packaged article and reduced influence of factors such as moisture, odour, dust and other factors on the article.

However, the adhesion between the "soft" coating and the opposing smooth surface of the film should be reversible, as it should allow the film to unroll when packaged and stored in a roll. In other words, the "soft" hermetic coating should be selected according to the nature of the coated substrate, on the one hand so that its adhesion on the opposite side of the substrate is weak enough to enable the packaging film to be unwound from the roll, and on the other hand so that it is strong enough to ensure that the package is almost sealed. And thus may be referred to as controlled adhesion. In addition, such controlled adhesion has the advantage that the package can be opened and closed multiple times without a significant reduction in the quality of the seal.

As indicated previously, one advantage of the present invention is that it has a wide range of possibilities in terms of the nature of the substrate used. Examples of suitable substrates are: a plastic film of 10 to 100 microns, such as oriented extruded polypropylene, polypropylene in the form of a cast film, polyester, polyethylene, oriented extruded polyamide or polyamide in the form of a cast film.

According to the invention, it is also possible to use a paper (sized or coated) substrate. In general, all support materials or flexible packaging materials are suitable as substrates for the present invention. These different substrates may constitute a single layer, a single metal layer, or layered and/or coextruded layers.

The choice of cold seal coating has no critical features. As long as the cold seal coating is "soft", pressure sensitive adhesives are contemplated, which are permanently bonded substances that adhere immediately to the surface of most materials under a relatively low simple pressure.

According to the general rule, pressure-sensitive adhesives are natural and/or elastomer-based compounds in connection with modified cellophane, phenol-formaldehyde resins or hydrocarbon resins (waxes). In addition to rubbers, polymers based on styrene, (meth) acrylic acid or vinyl esters, alone or mixed, are widely used in combination with resins. Finally, silicone resins may also be used. It is preferred to use a compound comprising a mixture of natural and synthetic rubbers and a copolymer of (meth) acrylic acid and styrene.

According to the inventionMing, according to 5 g/m²A cold seal coating is applied to the substrate.

The cold seal coating may be applied in solution, discrete, or even molten state.

Other features of the present invention will become apparent from the following detailed description of embodiments thereof, which proceeds with reference to the accompanying drawings, in which:

figure 1 shows the front of a first embodiment of the packaging sheet of the invention;

figures 2-8 show a sequence for packaging a piece of candy with the packaging sheet of figure 1;

figure 9 shows the front of a second embodiment of the packaging sheet of the invention;

figure 10 shows the front of a third embodiment of the packaging sheet of the invention;

figure 11 shows an enlarged section through the embodiment shown in figure 10;

figure 12 is a simplified variant of the embodiment shown in figure 10.

Fig. 1 shows the front, or print, side of a packaging sheet 20 cut from a film unwound from a storage roll (not shown) in the direction indicated by arrow a.

An example of a package in which the structure 22 is adapted to the arrangement of the fold lines during packaging is described below in terms of the cold seal coating applied to the structure 22. in the case of figure 1, there are two band structures 24, 26 of approximately W-shape and of width + -4 mm along two opposite edges of the packaging sheet 20 and a band 28 between the two W-shaped transverse structures along the third edge of the packaging sheet. On the side opposite the band 28, there are two areas of cold seal coating 30 and 32 in the corner areas. The tapes 24, 26 are distributed along the longitudinal edges, whereas the tape 28 is transverse, in contrast to the original film stored on the roll. These different strips of closure coating on the front face are located on the outside of the roll at different wraps of the roll.

The packaging sheet 20 of fig. 1 may be prepared as follows: a thin printed layer or primer (e.g. product 10-612205-4MX41 from SIEGWERCK) is applied to the front side of a 25 micron thick metallized or unmetallized oriented polypropylene film to improve the adhesion of the printing ink. The film is then printed using known techniques such as photomechanical or flexographic printing and offset printing. A layer of well-known protective lacquer is placed on the printed layer. A cold seal coating arrangement 22 is applied to the protective lacquer in the manner shown in figure 1. This deposition can also be carried out using known printing techniques.

For cold seal coating, products IP7905 or IP7936 from SWALE corporation may be used, for example, in terms of 3 g/m²The process is carried out. This is a seal coating which is only self-adhesive. In other words, the coating does not adhere to the untreated smooth surface of the reverse side of the film, which makes it easy to store and package the film in roll form, and unrolling does not present any problems. In addition, such sealing coatings have a low coefficient of friction (COF) for metals, on the order of 0.2 to 0.6, and a COF for metals of typically 1 to 1.5. This low coefficient of friction reduces the risk of jamming and sticking to the box to be folded.

The operation of wrapping a piece of candy substantially in the shape of a parallelepiped with the wrapping sheet of fig. 1 will now be described with reference to fig. 2 to 8. The packaging sheet is placed on the candy with the opposite or untreated side facing the candy so that the band 28 and the opposite side with the adhesive areas 30 and 32 are in the longitudinal direction of the candy and the W-shaped configuration is in the transverse direction of the candy. The edges of wrapping sheet 20 are folded over the longitudinal surface of the candy as shown in fig. 2.

The next operation is to fold each central region of the wrapped sheet with sides of formations 24 and 26 over the lateral surfaces of confectionery 34 with formations 24 and 26 as shown in figure 3. This is accomplished by folding the longitudinal edges of the wrapping sheet 20 along oblique fold lines 36 and 38. As can be seen in fig. 3, the two W-shaped structures 24 and 26(26 not visible in fig. 3) of the seal coating are positioned so that the two outer arms of the W-structures extend along fold lines 36, 38 and the interior of the V-shape lies against the lateral edges of the candy 34.

The next operation is to fold the two corners defined by fold lines 36, 38 inwardly in the direction of arrows 1, 2 in fig. 3 from each side of the confectionery 34. This operation places the outer band of the W-shaped closure coating structure, i.e., the bands along fold lines 36 and 38, on the inner V-shaped band and into the position shown in fig. 4. The folding sequence on both sides of the candy is obviously the same. As long as all the strips of the two W-shaped structures 24 and 26 are completely coincident and the cold seal coating used is completely self-adhesive, the arrangement of fig. 4 is a stable arrangement and the fold achieved so far is completely retained.

The following folding sequence is shown in fig. 5, namely folding the lower portion of the previously folded side flap over the lower surface of the candy 34. This is achieved by folding the longitudinal edges along oblique fold lines 40, 42, 44, 46 which turn the longitudinal edges into trapezoidal tongues 48, 50. The result of this folding sequence is best seen in fig. 6, which is a bottom view and a view of the hidden surface in the above figures.

It is also noted here that as can be seen in fig. 6, the two regions 30, 32 of cold seal coating are positioned so that their inward sloping edges (see fig. 1) extend along the fold lines 40 and 42 of the tab 48.

Fig. 7, 8 show the final stages of packaging. First, the tab 50 with the closure coating band 28 is folded over the inner surface as shown in fig. 7. The second tab 48 is then folded over the tab 50 to close the figure 8 shape.

When the tab 48 is folded, the two closure coating areas 30 and 3 overlap and partially adhere to the adhesive strip 28 of the tab 50. As a result, the arrangement of fig. 8 is a stable arrangement as long as the flap 48 is glued to itself and to the flap 50, and all folds are well maintained.

It should be noted, however, that adhesive strip 28 only adheres to adhesive regions 30 and 32 by its ends when tab 48 is pressed against tab 50. Instead, its central portion is in contact with the opposite side of the tongue 48 and is not bonded thereto. In other words, if the packaging sheet of fig. 1 guarantees a stable and permanently closed package, it does not guarantee a seal.

All the above-mentioned packaging sequences are carried out automatically on one packaging machine. In this context it is pointed out that the proposed packaging sheet is suitable for use in existing packaging machines without any modification. It should be noted that the above-described package is only one example of a definite way of folding by a machine. Other machines may fold at different fold line locations. In this case, it is necessary to adapt the model of the adhesive structure shown in fig. 1 to the structure of the folding lines effected by the folding machine, which in turn requires that the folding machine be adapted to the model of the adhesive structure more difficult.

A second embodiment of the invention will now be described with reference to figure 9, the packaging sheet being indicated generally at 52.

A packaging sheet, for example, oriented propylene, is prepared and printed, as in the case of fig. 1, with a layer of cold seal coating structure 22 applied thereto. Only a "soft" cold seal coating tape 54 is then applied to the adhesive tape 28. To do this, products 22-392 or 22-263 from the company CRODA can be used, in the range of 3 g/m²And (4) coating. The tackiness of tape 28 acts as a "primer" for the "soft" tackiness of tape 54.

The "soft" tackiness of the strip 54 is characterized by the ability to not only self-adhere, but also adhere to the untreated smooth surface of the opposite side of the packaging sheet 52. As a result, when the packaging sheet 52 is used in a packaging operation according to fig. 2-8, and the package is completed, the opposite side of the tab 48 will adhere to the adhesive strip 54 of the tab 50 when the tab 48 is pressed against the tab 50 (see fig. 7, 8) and its adhesive strip 54. Hereby is achieved a package which not only holds the folds well, but is also almost sealed.

According to another aspect of the invention, the "soft" seal coating is chosen to have a controlled adhesion, more precisely an adhesion sufficient to guarantee the hermeticity of the package, but insufficient to make the adhesion irreversible. In other words, the adhesive strip 54 should be able to be peeled off from the smooth surface of the packaging sheet 52 without difficulty. This allows the film to be stored in roll form without risk of rupture when unrolled.

Fig. 10 shows a third embodiment of a packaging sheet of the present invention, indicated generally at 56.

An oriented polypropylene film can be reused and printed by suitable means after a "primer" has been applied. A release coating 60 is then applied over the entire front surface. Suitable release products consist of a mixture of polyamide resin and polyethylene wax (e.g. 10-609345-3P from SIEGWERCK and 994404-X from SICPA) in an amount of 1.5 g/m²And (4) coating. The coating is then coated with the same cold seal coating pattern 22 as in fig. 1. And a dry cold seal coating tape, indicated by dashed lines at 58, is applied to the reverse side, approximately between the 30 and 32 regions of the front side. When the packaging sheet 56 is used in the package shown in fig. 2-8, the adhesive strip 58 will be located inside the tab 48 at the end of the packaging operation (see fig. 7), and when the tab 48 is folded, the adhesive strip 58 will adhere to the adhesive strip 28 of the tab 50 to close the package almost hermetically.

When the film of FIG. 10 is stored in roll form, the reverse adhesive tape 58 is generally in contact with the positive anti-tack coating 60, but does not adhere thereto. However, as the film is rolled up, and after a certain number of turns, the opposite adhesive strip 58 comes into contact with the front adhesive strip 28. This time, it is still possible to lift and unwind the roll of film due to the selection of the adhesive properties of the tape 58 and its controlled adhesion.

It should be noted that to facilitate unwinding of the stored film in rolls, the front face of the packaging sheet 52 of fig. 9 may still be provided with an anti-sealant coating similar to that of fig. 10.

Instead of a generally rectangular band of closure coating as shown, an oval band may be provided. This allows for a gradual tearing when opening the package or cutting the web of film with less risk of tearing.

Fig. 11 is an enlarged section through the thickness of the packaging sheet of the embodiment of fig. 10. In this example, the composition of the various layers marked a-F is as follows, layer a being the front side and layer F being the back side:

a: latex-based "soft" seal coatings in the range of 2-4 g/m²Coating, product IP7985 from SWALE corporation;

b: PVB (polyvinyl butylene) lacquer, product WO48825 from SWALE, with wax additives and having anti-adhesive properties for coatings on the F layer, in the range from 0.7 to 1.3 g/m²Coating;

c: color printing with DYNAVIN series PVB from SWALE at 2-3 g/m²The use is carried out;

d: SWALE 200970 type water "bottom layer" in a ratio of 0.4-0.8 g/m²The use is carried out;

e: a BEZ type co-extruded oriented polypropylene film supplied by VIBAC, 30 microns thick, having the following composition:

e1: plating a metal layer, 0.02-0.04 micron;

e2: a co-extruded layer, 1.5 microns, made of a blend of co-polymer and mono-polymer;

e3: single polymer core layer, 27 microns;

e4: a single polymer co-extruded layer having adhesion resistance to layer a.

F: dry cold seal coating based on latex in the range of 2-4 g/m²Coated, product IP7983 from SWALE.

A film constructed in this way enables a roll to be unwound and wound up 10 times without losing the adhesive properties required to form a closed package.

Figure 12 shows a simplified variant of the embodiment of figure 10. In this variant, the wrapping sheet 62 has only one band 64 of cold seal coating along one edge (transverse compared to the web before cutting) on the reverse side, corresponding to the band 58 of fig. 10, and another band 66 of cold seal coating on the obverse side of the opposite edge, corresponding to the band 28 of fig. 10. The packaging sheet may be constituted as described above with reference to fig. 11. By way of example, as previously indicated, the two bands 64 and 66 are oval in shape to facilitate tearing when unwinding the roll.

In other words, the closure coating structure 24, 26, 30, 32 of fig. 10 is not used in this variation of fig. 10. This variation may be used when an almost sealed closure and a non-sealed closure along the fold line that can be achieved by the embodiment of fig. 9 and 10 is not required. Conversely, when the packaging is effected in a box-folding machine, i.e., the folds described with reference to fig. 3-6 are completed at approximately the same time, the final stage of the packaging consisting of the overlapping of the closure coating strips 64 and 66 may retain the previously completed fold.

In addition, for the embodiment of fig. 9, a simplified variant similar to the one described above may also be provided.

Claims (9)

1. Packaging material for packaging an article (34), in particular a food product, consisting of a film which can be stored in rolls and can be cut into individual packaging sheets (20,52,56,62) for closing around the article (34) by folding, characterized in that each packaging sheet (20,52,56,62) of the film has a band of cold-seal coating at least along the transverse edges of the packaging sheet, ensuring a controlled self-adhesion of the packaging sheet which is sufficient to maintain the closure of the package, but insufficient to prevent the film from unwinding from the roll.

2. The packaging material of claim 1, wherein on each packaging sheet (20,52,56,62) of film there is a band (64,66) of cold seal coating along the transverse edges of the packaging sheet, one band (66) being on the front side of the packaging sheet and the other (64) being on the reverse side.

3. The packaging material of claim 1, wherein the front face of each packaging panel includes a plurality of cold seal coating areas (22) at least partially disposed about three peripheral edges of the packaging panel (20,52,56) and configured such that a substantial portion of the seal coating areas overlap and adhere to each other after the packaging panel is folded about the article and maintain the fold about the article.

4. A packaging material according to claim 3, wherein at least a central region of the fourth side is free of a seal coating and a region (54) of a soft cold seal coating is located on the front face of each packaging sheet (52) at least partially corresponding to the seal coating (22) of one of the three sides of the packaging sheet opposite the central region of the fourth side which is free of a seal coating.

5. A wrapping material according to claim 3, characterized in that each wrapping sheet (56) of said film comprises at least one dry cold seal coating zone (58) for overlapping at least partially on a band (28) of cold seal coating zones (22) of the front face of the wrapping sheet after the wrapping sheet is folded.

6. A packaging material as claimed in claim 5, wherein said region (58) of the cold seal coating on the opposite side of each packaging sheet (56) corresponds at least partially to the central region of the fourth side without the seal coating.

7. Packaging material according to one of claims 1-6, characterised in that the sealing coating of the sealing coating band (54,58,64,66) is applied as an oval band.

8. Packaging material according to claim 5 or 6, characterized in that the entire front face of each packaging sheet (52,56) comprises an anti-seal coating (60) applied before the application of the cold seal coating zone (22).

9. Packaging material according to one of claims 2,5 or 6, characterized in that the entire reverse side of each packaging sheet (56,62) comprises an anti-adhesive layer (E4) co-extruded in the matrix of the packaging sheet (56, 62).