CZ20011015A3 - Packaging material - Google Patents

Description

- 1 - 178852 / ΉΚ άοοή- 401S ~

Packaging material

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material that is suitable for packaging articles and consists of a packaging film which is divided into separate sheets to be closed by folding around the packaged product.

Without being limited by the field of application, the invention is more concerned with the field of packaging confectionery and chocolate products or other food products such as soup cubes.

BACKGROUND OF THE INVENTION The articles are generally individually wrapped in a rectangular sheet of preprinted wrapping film of a suitable size and shape, which in turn can be loosely placed in a packaging bag of appropriate size. For example, a packaged product having, for example, a parallelepiped shape is positioned in the middle of the back side, i.e., the unprinted side of the rectangular, wrapping film sheet, according to a conventional packaging method. The two longitudinal sides are then bent vertically upwards (or downwards, according to the position of the product and the type of packaging machine) about both longitudinal sides of the article. Thereafter, the lateral sides of the two sides of the article are bent vertically and their upper edges fold flat around the top surface of the article, the latter two operations being necessarily performed by gradual and oblique bending, with the pre-bent long sides. The package is completed by folding the upper edges (which in the meantime will form themselves, around the trapezoidal flaps), longitudinally over the top surfaces of the article. It should be noted, however, that depending on the shape of the packaged product and the type of packaging machine, another sequence of bending operations of the wrapping film is possible, where this sequence of bending operations takes place according to precisely defined folding lines. This bending line arrangement, wrapping film always remains the same for the same product packaged in the same packaging manner. A major problem that arises here, > is to keep the bends at the end of the wrapping so that the wrapper remains closed. This bending maintenance can only be ensured at the cost of a special choice of film used as a substrate, which must exhibit suitable mechanical properties, such as flexibility, and in particular a strong tendency not to return to its initial position after bending the wrapping sheet sheet during packaging.

This problem is particularly evident in the packaging of small products such as confectionery, such as candies, truffles, lollipops, candy, chocolate bars, etc., or soup cubes.

A known solution is to select a substrate particularly known for its flexible, such as paraffin paper, cellophane, aluminum laminates, or even synthetic films, containing a suitable amount of additive to enhance the flexibility of the substrate.

However, this solution significantly reduces the choice of foil used as a base for packaging or significantly increases the cost.

Also known are packaging films for. various products, such as soup cubes, where sealing is ensured by gluing. For this purpose, the foil has a heat-sealing layer on the front side, i.e. from the outside of the packaged article, the arrangement of which is adapted to the arrangement of the folds formed during packaging.

This method of packaging brings a disadvantage in that. that the machine must be specially adapted to this method to the extent that a heat source is required. Furthermore, if the heat source is formed by heating plates, the bonding can only be carried out on perfectly planar surfaces of the packaged product, and a relatively significant pressure is required, in addition to the time required to carry out the welding, which cannot withstand a number of products.

Another disadvantage is that this method of packaging is completely unsuitable for packaging. heat-sensitive products, in particular chocolate products, and does not allow the selection of a substrate for packaging having poor temperature resistance. EP-A-0 870 695 proposes a packaging film intended to be enclosed around a product, the front of which, outside the product, has a cold-sealing layer disposed in such an arrangement that the adhesive regions overlap. folding the wrapping film around the product.

Therefore, these adhesive areas provide bending retention when the wrapping film material has such a property that. does not maintain these bends. This. however, the wrapping film is provided with a hot-sealing coating which keeps the wrapping film closed and which has the above-mentioned drawbacks. Furthermore, this wrapping film has the further disadvantage that the back side must include anti-adhesive tapes to allow the film to be unwound from the bobbin.

EP 0 225 987 discloses a packaging film having a cold-sealing adhesive region on the front and rear sides, namely two longitudinal strips on the front side and on the rear side, respectively. In order to form this film in a wound form on the spool, these different adhesive areas must be positioned so that they do not overlap during winding. Such an overlap would in fact cause the various regions to stick together and prevent the film from unwinding from the spool. However, this limitation with respect to the location of the adhesive areas includes limitations corresponding to the bend arrangements and packaging methods. «· · · · · · · · · · · · · · · · · · · · · · · ·

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In fact, the above-mentioned publications pursue the same objectives, namely to apply adhesive areas to the film, to maintain bends, and to provide the film to be wound on a spool. The problem is that as described below, if the film contains two self-adhesive regions on the back and on the front when it is wound on a spool, there is a risk that some of these adhesive areas will be two. adjacent windings are overlapped on the coil, and mutually. stuck, which would prevent the film from unwinding from the reel.

These two writings seek to solve this problem by various means. EP-0 870 '695 foresees the use of cold-adhesive adhesive-only areas on the front side. Therefore, there is no danger of overlapping during winding. On the other hand, in order to solve the problem of keeping the bends, this file envisages a hot-adhesive coating on the back which leads to the aforementioned disadvantages.

EP-0 225 987, on the other hand, is looking for a special adhesive, cold backing layer for the back side with respect to the layers on the front and vice versa, so that during the winding two adjacent windings are arranged side by side and there is no overlap. However, this solution imposes limitations on the packaging methods in that it is necessary to determine the bending arrangement according to the location of the adhesive areas, although it is the opposite of what is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel package that allows the choice of film to be significantly expanded and which makes it possible to adjust the film to a reel without any restriction on the packaging method.

To achieve this goal, according to the invention, a packaging material according to claim 1 is created. The Applicant has surprisingly discovered that pre-at least partial coating of a film used as a wrapping material with a precisely cold-glued layer allows for bending to exhibit excellent bending retention. the wrapping film by bending, while at the same time allowing the film to be wound onto the spool.

This fact, and the fact that the substance used as an adhesive layer exhibits little or no adhesion to a smooth surface or to a surface adapted for this purpose, but, on the other hand, exhibits good adhesion when applied to itself, which is the case in bending. Thus, bending maintenance is simply ensured by lightly compressing and offsetting certain areas of the adhesive layers, and this is achieved without additional accessories than those needed to bend the package.

Cold bonding according to the invention is understood to mean bonding which occurs immediately by simple contact at a temperature of about 0 to 50 ° C. In fact, the temperature is not a critical parameter when it comes to bonding with an adhesive layer for cold bonding and has practically no effect on the quality of the adhesive bond obtained. Thus, bonding can be achieved without any additional heat, at ambient ambient temperature in which the packaging unit is located.

In fact, the adhesive layers have been previously used for cold bonding, especially on the. which are not subjected to deformation or are subject to only minor deformations. In fact, considerable blocking problems due to the adhesive properties of the cold-adhesive adhesive layer in all applications of this cold-adhesive adhesive layer to the non-planar substrate can be expected.

Accordingly, the present invention allows for the use of cheaper films and exhibits better properties (stiffness, printing capability, · · · · · ♦ · · ♦ · · • · · · · · · · · · · · ··· *····) The aesthetic appearance for the packaging of products is not limited as to the shape of the products.

As far as the use of rigid foils is concerned, it should be noted that so far rigid foils for packaging have not been used, which must be closed by bending. These films have. a very low bending retention capacity.

Regarding the problem of adjusting the winding film to the spool, compared to the solutions in the two prior art publications, this application creates a completely different solution, which has been impossible until now, and which is to tolerate the misalignment of different adhesive areas when it is the film to be wound on a spool. To this end, the invention provides for the selection of a well-defined, cold-adhesive adhesive layer, which is what is defined in the " controlled adhesion ", i.e., adhesion strength sufficiently strong for the purpose of this case, but insufficient to prevent repeated peeling. Thus, the film may be unwound several times from the storage spool, without excessive resistance, even from the inner winding where the compression is normally higher. Obviously, this solution offers significant advantages over the solutions proposed in the aforementioned documents, within the limits where the same adhesive can be provided everywhere (i.e., more than for hot bonding) and where adhesive areas can be provided at the desired locations depending on the shape of the packaged product and the bending sequence.

According to a preferred embodiment, the backsheet region of the adhesive layer comprises two "W" shaped strip structures along two opposing sides of the wrapping film, one strip along the third side of the wrapping film, and between the two "W '" and two regions at two corners of the fourth side of the wrapping film. - 7 - - 7 - · · · · · · · · · · · · · Adhesive-coated tapes placed according to the bend arrangement may have a width of about 4 mm. \ T mm.

The structure of the adhesive tape strips may be of various shapes depending on the packaged product and depending on the bending sequence. ,

In addition to the tape structure along the bends being performed, each sheet of wrapping film may comprise a tape with an adhesive layer along the edge of the third side. This strip is located on the flap which at the end of the packaging method will be folded first on the base of the packaged product. and will provide bonding to the flap that will be folded last. In addition, each sheet of wrapping film may comprise additional adhesive regions to allow the tab to be adhered to last to the base of the packaged article, and thereby contribute to maintaining the wrapping condition.

According to one aspect of the present invention, the adhesion achieved by overlapping the tapes with the cold-sealing adhesive layer is not irreversible, since it must allow the film to unwind when the film is adapted and deposited on the reel without the risk of breaking it. In other words, it is necessary to select an adhesive layer depending on the type of substrate to which it is applied, on the one hand its self-adherence to itself is weak enough to allow unwinding of the wrapping film from the spool and to be strong enough to provide a quasi-hermetic closing the package. Thus, controlled adhesion can be discussed. This controlled adhesion has the advantage, among other things, that the package can be opened and closed several times without significantly reducing the quality of the adhesion.

As mentioned above, one of the advantages of the present invention is that it allows for a wide range of possibilities in terms of the type of substrate used. Examples of suitable substrates are plastic films of about 10 to 100 microns thick, extruded, and polypropylene, polypropylene, of polypropylene in the form of extrudates. cast foil, polyester, polyethylene, extruded and oriented polyamide, or polyamide cast foil.

It is also possible according to the invention to use a substrate of paper (glazed or coated). Generally speaking, each backing material or each flexible packaging material may be suitable as a backing according to the present invention. These various substrates may consist of a single layer, a single metallized layer or a plurality of layered layers and / or coextruded layers.

Generally speaking, pressure-sensitive adhesives are compounds based on natural and / or synthetic rubber, associated with modified cellophane, phenol-formaldehyde resins or hydrocarbon resins (waxes). In addition to rubbers, polymers based on styrenes, (meth) acrylic acid or vinyl ethers are used widely, alone or in combination, as well as in combination with resins. In particular, compounds containing mixtures of natural and synthetic rubber and copolymers of (meth) acrylic acid and styrene are used.

According to the present invention, the cold adhesive layers are applied to the substrates in an amount of about 1 to 5 g / m 2. The cold-bonding layers may be applied in the form of a solution / dispersion or even in a molten state. List of drawings in the drawing

Further features and features of the invention will be apparent from the following detailed description of several preferred embodiments, with the aid of the accompanying drawing, in which: Figure 1 shows the front side of one embodiment of a wrapping sheet, in Figures 2 to 8; · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 9 · Fig. 10 shows the sequential sequence of the candy wrapping operation of the wrapping sheet of Fig. 1; Fig. 10 shows the front side of the exemplary embodiment of Fig. 1 with the backing adhesive structure; 10, and FIG. 12 shows a simplified embodiment of the embodiment of FIG. 10.

Fig. 1 shows the front side or printed side of the wrapping sheet 20, after being cut off from a film unwound from a deposition spool (not shown), in the direction shown by arrow A.

The cold-sealing adhesive layer is disposed within the structure 22, which is adapted to the fold lines I formed in the packaging, an example of which will be described below. In the case of FIG. 1, there are two strip structures 2A and 295, about 4 mm wide, approximately " W ", along opposite sides of wrapping sheet 20, and strip 20 along the third side of wrapping sheet 20, between two side sheets "W" structures. Also, on the opposite side to the strip 28, there are two adhesive regions 30 and 32 in the region of the corners for cold bonding. Because of the film initially deposited on the spool, the ribbons 24 and 26 are positioned along the longitudinal edges, while the strip 28 is positioned transversely. On the spool, these various adhesive tape tapes on the front side are located on the outside of the various coil windings. ·

The packaging film sheet 20 of Figure 1 can be produced by depositing a thin printed layer or base coat (e.g., SIEGWERCK's 10-612205-4 MX41) to improve ink adhesion to the front of the film. · 25 micron-oriented, polypropylene, metallised or non-metallised oriented polypropylene. The coating is applied by a printing technique known per se, for example by heliographic or flexographic technique, or by offset printing. A protective lacquer is also applied to the printing, which is also known per se. Cold-bonding layer structures 22, according to the pattern shown in FIG. 1, are applied to the lacquer. This deposition can also be accomplished by printing techniques known per se.

SWALE's IP7905 or IP7936 can be applied to the cold-bonding layer, for example 3g / m 2. This is an adhesive layer which adheres only to itself. In other words, this layer does not adhere to the untreated smooth back of the film, which allows. so that the foil is simply stored and adapted to the coil without any unwinding problem. Moreover, this adhesive layer is of such a quality that it has a low coefficient of friction (COF) on the metal, which is in the range of 0.2 to 0.6, while this coefficient of friction (COF) on the metal. it is normally in the range of 1 to 1.5. This low, coefficient of friction reduces the risk of creasing and sticking to the bent box.

Referring to Figures 2 to 8, a substantially parallelepiped-shaped, substantially parallelepiped packaging operation will be described. 20 of the wrapping film of FIG. 1. This sheet 20 is placed on the bottom 34 with its back side or untreated side facing the candy 34 so that the tape 28 and the opposite side with the adhesive regions 30 and 32 are positioned in the longitudinal direction of the candy 34, and "W " were placed in the transverse direction of candy 34. The sides of the wrapping sheet 20 are then folded down over the longitudinal walls of the candy .34, as shown in FIG. 2. - 11 - 11 - • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · In the following operation, the central area of each side of the wrapping sheet 20 is bent, the sidewall structures 24 and 26 of the candy 34 as shown in FIG. 3. This operation is performed by bending, with the longitudinal sides of the wrapping sheet 20 following the oblique bending lines 30 and 38. As can be seen in FIG. 3, the two " W " (wherein the structure 26 is not visible in FIG. 3) with the adhesive layer are positioned so that the two outer members of these structures in the " W " extending along fold lines 36 and 3 * 8, and that the " V " was placed on the side of candy 34. In the following operation, two sides of the film 34 are bent from each side of the candy 34, defined by fold lines 36 and 38, in the direction of arrows 1 and 2 in FIG. a " W " adhesive layer, i.e., these strips extend along fold lines 36 and 38, on " V " and the result is an arrangement as shown in FIG. 4. It will be appreciated that this bending sequence extends on both sides of the candy 34. Provided that all the tapes of both the " W " and that the used cold-sealing adhesive layer adheres perfectly to itself, the arrangement of FIG. 4 being a stable arrangement with perfect maintenance of the hinges previously performed. The following bending sequence is shown in FIG. 5 and bends the lower side wall portions that have been bent and folded to the underside of the candy 34. This operation is performed by bending, with longitudinal sides following the oblique fold lines 40, 42, 4, 46, which deform the longitudinal sides of the trapezoidal flap 48, 50. The result of this bending sequence is clearly shown in FIG. 6, which is a bottom and side view covered in the preceding figures. • · · «······ * · · ···· · · · tli # ·· · · ·····

It should be noted that both the cold-sealing areas 30 and 32 are positioned such that their oblique inner edges (see also FIG. 1) extend along the fold lines 40 and 42 of the tab 40 as shown in FIG. 6.

FIG. 7 and 8 show the last stage of packaging. First, the tab 50 provided with the adhesive tape 28 is folded on the inside as shown in Fig. 7. The second tab 48 is then folded onto the tab 50 to form the arrangement of Fig. 8.

When the flap 48 is folded, the two adhesive regions 30 and 32 are partially overlapped and are applied to the tab 28 with the flap adhesive layer 50. As a result, the flap 84 adheres to itself and to the flap 50 that Fig. 8 is a stable arrangement with good maintenance of all bends.

It should be noted, however, that when the flap 48 is folded onto the flap 50, the adhesive layer 20 adheres only with its overlaps to the adhesive regions 30 and 32. In contrast, the middle portion thereof contacts the back of the flap 48 to which it does not adhere. In other words, if the wrapping sheet 20 of FIG. 1 provides a stable and durable wrapping, it does not provide a sealed wrap.

Each package sequence described below is performed automatically in a packaging machine. In this context, it is important to note that the designed wrapping sheets 20 are suitable for existing packaging machines without the need for any modification or adaptation. It should be noted, however, that the packaging described below is merely an example of a bending arrangement on a designated machine. On other machines, bending can be performed according to different bending line arrangements. In this case, it would be appropriate to adapt the pattern of the adhesive structures shown in FIG. 1 to arrange the structure of the adhesive structures. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · The bending lines performed by the bending machine, the opposite of which would be more difficult.

FIG. 10 shows a preferred embodiment of the sheet " 56 packaging films according to the present invention. Again, a foil of oriented polypropylene can be used, which is suitably printed, possibly after application of a primer. An antiadhesive layer 6CL is then applied to the entire front surface. Suitable antiadhesive articles consist of a blend of polyamide resin and polyethylene wax (e.g., SIEGWERCK and 994404-X SICPA products 10-609345-3P) deposited at 1.5 g / m 2. A cold-bonding adhesive pattern 22 is then applied to this layer, the same as that of FIG. 1. A backing 58 is then coated with a cold-adhesive adhesive layer, approximately between the 30th and 32nd front regions. as shown in FIG. 10 with a dashed line. When the wrapping sheet 56 of the wrapping described in FIGS. 2 to 8 is used, the adhesive layer 58 will be placed at the end of the wrapping operation (see FIG. 7) on the inside of the tab 48 and, after folding, adheres to the tape 20 with the adhesive layer of the flap 50 to form a quasi-hermetic package.

When the film of FIG. 10 stored on a spool, there are tapes. 58 with an adhesive layer on the back generally in contact with the anti-adhesive layer 6 'on the back side of which it does not adhere. However, the adhesive strips 58 are. however, during unwinding and after several counts, they also get into. contact with the adhesive tape 28. In this case, by selecting the type of adhesive for the tapes 28 and 58, and its controlled adhesion, there is also the possibility of peeling off and unwinding the film from the reel, without moving the film, and without significantly reducing the adhesive properties of the tapes 28 and 58. » * * · ···· ·····

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Instead of providing the tapes with an adhesive layer having generally,. a rectangular shape, as shown in the figures, can be used with strips of oval shape. This arrangement allows for gradual release, with a lower risk of tearing, when the package is opened or when the film is unwound from the bobbin.

FIG. 11 shows an enlarged embodiment of the film 56 of the wrapping film of FIG. 10 in an enlarged scale and in cross-section. In this example of the preferred embodiment, different layers are formed, denoted by the letters A to F, wherein the layer A forms the front side and the layer F back: A: latex-based adhesive layer applied at 2 to 4 g / m2, product IP 7985 by SWALE, B: varnish PVB (polyvinyl butynal), product WO 48825-SWALE. with wax admixtures and anti-adhesive properties, fd coating F and applied at 0.7 to 1.3 g / m2, C: color printing with PVB color, Dynavin series, coated with SWALE and applied at 2 to 3 g / m2 , D: primer, mass - aqueous solution, type 200970 from SWALE deposited in a quantity of 0.4 to 0.8 g / m2, E: foil of oriented polypropylene, coextruded, type BEZ, provided from VIBAC, thickness 30 μ and consisting of:

El: metallised layers 0.02 to 0.04 μ, E2: coextruded layers of 1.5 μ, composed of a mixture of copolymers and homopolymers, E3: homopolymer cores of 27 μ, E4: coextruded layers homopolymers with anti-adhesive properties for layer A. F: latex-based cold-sealing adhesive layer, applied at 2 to 4 g / m 2, of product IP 7983 to SWALE. - 15 - · * ·· · · · · · · · · · · · · · ·

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The film thus formed can be unwound and wound up to ten times on the spool and the spool, without losing the adhesive properties required to form the closed package.

FIG. 12 shows a simplified variant of FIG. 10. In this variant, the wrapping film sheet 62 comprises simply on the back side, a portion of the edges (transverse to the film wound on the spool, before cutting it), a strip 64 with a cold-sealing layer corresponding to the strip 58 of FIG. at the opposite edge of the front, another cold-sealing tape 66 corresponds to the ribbon 28 of FIG. 10. The wrapping film 62 may be as described in FIG. 11. Both tapes 64 and 66 have been shown for expelling, and as indicated above, are in an ovoid shape to facilitate release when unwinding from the spool. In other words, in this variant of FIG. 10, the adhesive layer structure of FIG. 10 is not used. 24, 26, 30, 32. This variant can be used when a quasi-hermetically sealed closure is not required. Fig. 10, and when the closure along the fold lines is not sealed. In contrast, the last stage of the packaging formed by the overlapping of the adhesive regions 54, 66 allows the pre-formed bends to be maintained when packaging is performed in a bent box machine, i.e. when all the bends shown in FIGS.

Claims (4)

16 P A T E C O N T R O P O R E 1. Packaging material for the treatment of products (34),. especially food products > recovered from the film being wound in the longitudinal direction on the spool and transversely divided into separate sheets (56, 62) and intended to be closed by bending around the article (34), wherein the film comprises on each sheet (56, 62 ), along each transverse edge, tapes (28), (58), (64), 66) with a cold adhesive adhesive layer, where one strip (28), (66) is located on the front side and the second strip (58) ), (64) on the back side of the sheet, wherein the strips (28), (58), (64), 66) are secured by overlapping the final closure of the package after the last bending sequence, the mutual adhesion between said strips (28) , (58), (64), 66) is a controlled adhesion sufficient to maintain closure of the package but insufficient to interrupt the unwinding of the film from its bobbin, when in contact with each other in a wound state between the strip (28), (66) at the front side and strap (58), (64) on the back side. Packaging material according to claim 1, characterized in that the front side of each sheet comprises areas (22) of a cold-sealing adhesive layer positioned at least partially along three sides at the edge of the sheet (56), in such an arrangement that most of these areas are offset after bending the sheet around the article, adhering to each other and keeping the bends around the article. Packaging material according to Claim 1 or 2, characterized in that the adhesive layer of the adhesive layer strips (58) (64) is arranged on the rear side in the form of an oval strip. ·· ·· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Packaging material according to claims 1 to 3, characterized in that each sheet (56, 62) comprises on its entire front side an anti-adhesive layer (60) which is applied upstream of the adhesive layer of the adhesive-layer regions for cold bonding.