JPH06211239A - Packing container with belt-shaped opening means - Google Patents

Abstract

PURPOSE: To provide a package container that is provided with a seal opener, composed of plastic coated packaging material, equipped with a sealing fin laterally extending on the container wall, buried under the sealing fin with unsealing strip of laminated material, and that draws apart the sealing fin that has closed the container wall and exposes a corresponding spout when tearing off the unsealing strip. CONSTITUTION: An unsealing strip 10 has an inner layer, a sealable plastic outer coating and an intermediate layer 16 disposed between the inner layer and sealable plastic outer coating. In order to ease unsealing of the packaging container, the intermediate layer of the unsealing strip 10 consists of a material with a nature that makes the bonding strength between all material layers contained in the unsealing strip 10 and mutually facing plastic coating of packaging material in the sealing fin 3 greater than the inner adhesive bonding strength of the intermediate layer so that adhesive layer exfoliation is produced in the intermediate layer of the unsealing strip 10 when it is torn off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening device for a packaging container made of a plastic coating material, of the type having a sealing fin extending laterally on the container wall, the packaging material layer facing each other in the sealing fin. Plastic coatings of each other are joined together as a sealing joint or seam, and a layer of wrapping material is fitted along at least a portion of the sealing fin to an opening strip embedded in the sealing fin, the strip being a plastic of packaging material. An opening device which is a laminated material having an inner layer sandwiched between outer material layers hermetically bonded to the material.

[0002]

BACKGROUND OF THE INVENTION In the field of packaging industry and technology, there is a one-time disposable packaging container or carton formed by a plastic coated packaging material for packaging and carrying liquid food products such as milk, juice, wine and the like. Often used. The exact structure of such packaging material depends on the product to be packaged, but usually the body or carrier layer of paper or cardboard or cardboards which gives the package the required rigidity and shape stability and the packaging container. In addition to being liquid-tight, it also has a thermoplastic, preferably polythene outer coating which can give the packaging a permanent, desired final shape by so-called heat sealing.

[0003] Disposable packaging containers, as now envisioned, are modern and streamlined packaging that have generally been able to be molded, filled and sealed using strips or prefabricated dough materials. Manufactured by machine. For example, Tetra Brik (R) type packaging containers are manufactured from a strip of material, which is first transformed into a tube by joining the longitudinal edges thereof to one another in a longitudinal overlap joint or seam. The tube is then filled with the required contents and then divided into closed packaging units by repeating the transverse seal along the mutually spaced transverse tube sections below the level of the contents of the tube. It Subsequent additional folding and sealing operations result in a special cushion-like wrapping with the required geometrical final shape (in this particular case, a parallelepiped), at which time the packaging container Double-walled triangular flaps develop in the corners. Of these flaps, both flaps in the upper corner are folded down and sealed against the adjacent vertical wall, while both flaps in the lower corner are folded against the flat bottom wall of the packaging container. And sealed.

The above-mentioned conventional parallelepiped packaging container thus has two sealing fins due to the lateral sealing of the tubes, in which the facing material layers of the packaging material are mutually melted by surface melting. To form a sealing seam joined inwardly to. In this example, one of these two sealing seams is located on the flat top wall of the packaging container, across which it is folded and sealed towards the side wall of the packaging container. From one end to the other, while the other sealing fin is correspondingly located on the bottom wall of the packaging, traverses this wall and from the tips of the two lower corner flaps folded towards the bottom wall of the packaging. It will extend to the tip. Further, the packaging has a longitudinal sealing seam forming a portion of the longitudinally overlapping seams of the tube formed as described above, and this at a point between the corner hangers of the upper and lower end walls of the packaging, respectively. It intersects with the horizontal sealing fin.

What is required of disposable packaging containers of the type described above is that not only is the packaged product protected as well as possible, but it is also easy to handle during transport and use. That is. To facilitate the handling of the packaging container during use,
It is often necessary to provide some type of unsealing device to facilitate access to the contents of the package and to easily guide its discharge from the packaging container as a single stream. To be done.

In the above-mentioned Tetra Brik (R) type packaging container, one of the two upper triangular corner hanging pieces is generally used as a spout, and the packaging container itself normally releases the corner hanging piece. Lifted from a position folded down toward the side wall of the packaging container and tearing or cutting the sealing fin extending over the flap to form a conduit communicating with the interior of the packaging container.

[0007] There is some difficulty in separating the triangular flaps along a pre-provided tear indicator or hole, and the cutting of the sealing fins presupposes the use of some type of tool, such packaging To solve the problem of opening the container, it has been proposed in the past to use tear threads or tear strips, for example as described in Swedish patent specification 402,899. In such an example, the tear thread or tear strip is located within the sealing fin from the tip of the triangular corner flap that serves as the spout so that it is accessible from the outside of the packaging container. It is embedded in a sealing fin to extend at the intersection with the overlapping seam. When the packaging container is to be opened, the part of the tearing thread or the tearing strip that can be approached from the outside is pulled upward and rearward, whereby the sealing seam in the sealing fin between the intersection and the triangular corner hanging piece is cut. So that a corresponding spout is formed.

However, it has been found that this prior art method of unpacking using threads or strips is not always satisfactory. The main reason for this is that the thread or strip rarely cuts the sealing seam directly, cutting between the paper material and the plastic coating on one side of the material layer, thus exposing the paper or cardboard layer of the packaging material, This is because the package contents come into contact with the exposed absorptive fiber surface to make it soaked in water and lose its rigidity.

[0009] As another conventional technique for solving the problems associated with the opening of a packaging container of the type currently under consideration, there is, for example, European Patent Application No. 0083441. In this case, the unsealing device consists of a strip of laminated material, which is embedded in a sealing fin and which, in part, has a high tensile strength and tear resistance, such as oriented polyester, nylon or metal foil. It comprises an inner layer and a heat-sealing plastic material, preferably polythene, which is partly arranged on both sides of said inner layer. In such a case, the tear strip, similar to the tear string or tear strip described above, extends from the tip of the corner flap, which acts as a spout, to a point past the intersection of the sealing fin and the vertical overlap seam of the packaging container. The portion of the sealing fin that fits the strip is tightly sealed to the opposing thermoplastic coating of the packaging container. From a sealing point of view, the material of the inner layer of the tear strip is either incompatible with the thermoplastic coating on its outer side, or not at all, so that the inner layer of the tear strip has some type of adhesion. Subjected to a force-improving pretreatment, so-called primed and / or selected a suitable sealing temperature, the required sealing strength between the inner layer of the tear strip and its thermoplastic outer coating, That is, binding is allowed to occur. What is needed in this example is that the sealing strength between the inner layer of the tear strip and its thermoplastic outer coating is such that the thermoplastic outer coating of the tear strip and the packaging material itself. It is weaker than the sealing strength at the same time, and at the same time, it has a large sealing strength to prevent accidental delamination of the opening strip when the packaging container receives an external force during its normal transportation and handling. It is that you are.

Unpacking a packaging container having a laminated tear strip of the type described above is such that when the tear strip tears the sealing fin, the interfacial layer between the inner layer and the thermoplastic outer coating is delaminated and teared. It is based on the idea that both thermoplastic outer coatings are left adhered to the packaging material in the area of the pouring spout that is now formed, while at the same time exposing the inner layer which has been exposed. A problem associated with tear strips by this conventional technique is that it is practically difficult to optimize the bond strength between the inner layer of the tear strip and its thermoplastic outer coating, And to adjust the adhesive pretreatment or undercoating and / or the adhesive strength of the inner layer of the tear strip to prevent accidental delamination of the tear strip due to too low a bond strength. Temperature selection is often required, which inevitably results in excessive bond strength between the inner layer and the thermoplastic outer coating. With this, the tear strip becomes difficult to tear unless a large tensile force is applied, and / or the tear of the tear strip often causes tear of the thermoplastic inner coating of the packaging material itself, This will expose the fibrous layer of packaging material in the area of the spout.

[0011] Swedish patent specification 459,916 describes another prior art unsealing principle using laminated unsealing strips, which is similar to the one described above in terms of tensile strength and tear resistance. It has an inner layer of superior material, preferably polyester, and an outer coating of sealable plastic material, preferably polythene. In such a case, the adhesive strength of all material layers contained within the tear strip is deliberate to allow its tearing without causing delamination between the layers within the tear strip. It has been raised. Instead, to ensure that the tearing of the tear strip takes place without requiring the use of excessive physical force, a fibrous layer of packaging material at the part of the sealing fin corresponding to said strip. And a sealing-weakening agent, such as water glass, is placed so as to be located between the thermoplastic inner coatings, thereby weakening the sealing strength between the packaging material layers, and the thermoplastic outer coating of the tear strip. And the thermoplastic inner coating of the packaging material has a bond strength greater than the bond strength between the fibrous layer of the packaging material and the thermoplastic inner coating. Tearing the tear strip thus also tears the plastic coating in the sealing-weakening zone of the sealing fin, which tears the tear strip accordingly, and at the same time the fiber layer impregnated at least partially with water glass is the area of the spout. It is exposed inside. For successful operation, the opening device is premised on that at least most of the exposed fiber surface is impregnated with a water glass film which resists moisture and liquids, but in practice The requirements are difficult to meet, and the fiber surface is usually unprotected after the tear strip is torn.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel type of unsealing device in which the aforementioned drawbacks are effectively eliminated.

[0013]

According to the invention, according to the invention, an opening device as described above, wherein the opening strip has an intermediate layer between its inner layer and each corresponding outer layer, The adhesive bond strength between all material layers in which the material of the intermediate layer is contained in the tear strip and between the outer layer of the tear strip and the plastic coating of the packaging material is It is characterized in that it is made larger than the adhesive bond strength.

The opening device according to the invention is therefore based on the principle that a complete delamination takes place in one material layer contained in the opening strip, which is contrary to the opening device according to the prior art described above. In the first case, the tear strip causes delamination between the two material layers contained therein, in the latter case the two material layers contained within the packaging material, namely the fibrous layer and the thermoplastic material. Peeling occurs between the cover and the cover, and the tear strip itself is torn as it is without peeling.

Internal to one of the material layers of the tear strip,
Or the fact that an adhesive delamination occurs means that in particular the tear strip according to the invention is removed without causing damage to the packaging material itself in the opening zone, and the fibrous layer of the packaging material is its durable, intact. The tear strip is well protected by the thermoplastic coating of and tears the tear strip, even if there is some over-protection, by the part of the material layer that has internal or adhesive delamination of the tear strip. Even afterwards, it remains adhered to the thermoplastic coating of the packaging material and at the same time easily adjusts the internal or adhesive bond strength of the peelable interlayer of the tear strip to exert excessive tensile force The advantage of this is that the tear strip can be easily torn without any further effort.

According to a preferred embodiment of the invention, the adhesively debondable intermediate layer of the tear strip is a physical mixture of polythene and polybutene, ie both of the abovementioned components,
It comprises a mixture that is physically mixed with each other without the addition of other elements that cause chemical interactions or structural bonds between them. The proportion of each component contained in the interlayer is determined by the required adhesive bond strength of the material, and in the case of the present invention the above-mentioned optimum required between accidental opening and artificial opening. Are selected to satisfy According to the invention, the proportion of polybutene in the intermediate layer should be a value between 10% and 50% by weight, which means that an intermediate layer with a polybutene content of 10% by weight or less is delaminated. This is because the tensile force required for is extremely large, and on the contrary, in the intermediate layer having a content of more than 50%, delamination is likely to occur, and there is a risk of accidental opening of the packaging container. According to the invention, a particularly preferred intermediate layer has a polybutene content of approximately 25% by weight.

[0017]

EXAMPLE A packaging container 1 shown in FIGS. 1 and 2 is of the above-mentioned Tetra Bruk (R) type. The packaging container 1 has an overlapping vertical sealing seam 2 and a sealing fin 3, which extends along an upper end wall 4 of the packaging container 1. As shown, the packaging has a triangular, double-walled flap 5, which serves as a spout or spout, in FIG. 1 the triangular flap is broken, and the side wall 6 of the packaging, That is, when the hanging piece 5 is folded downward, it is partially lifted from the side wall that seals the packaging container.

At the intersection 7 of the longitudinal seam and the transverse sealing fin 3, the edges of the overlapping material are cut obliquely along the area 8 and at the intersection 7 a part 9 of the tear strip 10 embedded in the fin 3. Is protruding. The projecting strip portion 9 is suitably designed as a pull ring or pull hole, or as a member with it, which makes it easier to pull the strip.

As shown partially in FIGS. 3 and 4, which are enlarged cross-sectional views of the packaging container 1 taken along lines I-I and II-II, respectively, the packaging container 1 is a body of paper or cardboard or It is formed by a packaging stack consisting of a carrier layer 11 and a thin outer coating 12, 13 of thermoplastic material, preferably polythene. A strip 10 is located between the mutually facing material layers of the sealing fin 3, which strip extends from the tip 5a of a triangular corner flap 5 having a double wall to the longitudinal seam 2 and the sealing fin 3. Along the area extending to the intersection 7 of the strip 10, the strip 10 embedded in the sealing fin can be brought into close proximity thereto by the projecting portion 9, preferably in the form of a ring or loop thereof.

In the illustrated example, the strip 10 of laminated material has an inner layer 14 of a high tensile strength plastic material, preferably polyester, and an outer layer 15 of a sealable material, preferably polythene. ing. Further strip 1
0 is hermetically bonded to the surrounding material layer of the sealing fin 3 by surface melting between its plastic outer coating 15 and the plastic inner coating 12 of the material layer.

The strip 10 has an intermediate layer 16 between the inner layer 14 and each corresponding thermoplastic outer coating 15 in order to facilitate the separation of the strip 10 when the packaging container is opened.
The material of this intermediate layer is such that the adhesive bond strength between all the material layers contained in the tear strip and between the outer layer of the tear strip and the plastic coating 12 of the packaging material is such that in the interlayer 16. It has the property of being considerably larger than the internal adhesive bond strength. In the illustrated embodiment, the intermediate layer 16 consisting of a physical mixture of polythene and polybutene comprises 10% by weight.
To 50% by weight, preferably about 25% by weight of polybutene. The intermediate layer 16 is extruded in a state where no structural or chemical bond is generated between the two components contained in the mixture. By mixing polybutene in the intermediate layer 16 in a mixing ratio as described above, all of the materials contained in the tear strip are bonded and the tear strip is placed in the portion of the sealing fin that fits the strip. It can be tightly sealed to the thermoplastic inner coating 12 of the packaging material and its bond strength can be substantially greater than the inner adhesive bond strength of the intermediate layer 16.

In case of opening the packaging container 1, FIG.
And operate in the order shown in FIG. First, the double-walled triangular corner flap 5 that is sealed against the side wall 6 is lifted so that the flap is substantially flush with the upper end wall 4 of the packaging container as shown in FIG. Then the freely projecting end 9
Is gripped at the intersection 7 of the vertical sealing seam 2 and the horizontal sealing fin 3 of the packaging container, and the end portion 1 has a large pulling force due to the inner adhesive bond strength of the intermediate layer 16 by the end portion.
0 towards the top rearward, to the right in FIG. 2, so that the tear strip strips the layers within each intermediate layer 16 so that the spout 17 is exposed. As can be seen from FIG. 4, the tear-away tear strip now comprises an inner layer 14 and associated portions 16 'of the peeled intermediate layer 16 on either side thereof, while the remaining portion of this layer is tear-open. With the thermoplastic outer coating 15 on the strip, it remains adhered to the packaging material left in the area of the spout 17.

According to the experiment, since the unsealing strip 10 is embedded in the packaging container 1 according to the present invention, there is a risk that the unsealing strip 10 may be peeled off or confused without applying an excessive force. It became clear that it could be opened easily without it. It should be noted that this unsealing method can be carried out without fear of exposing any part of the absorbent paper or cardboard fibers of the packaging material to the unsealing area.

The present invention is not limited to the embodiments shown and described above, but various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 shows an upper part of an unopened packaging container with an opening device according to the invention.

FIG. 2 is a diagram showing a packaging container in the opening process.

3 is a cross-sectional view of the packaging container of FIG. 1 taken along line I-I.

4 is a cross-sectional view of the packaging container of FIG. 2 taken along line II-II.

[Explanation of symbols]

 1 Packaging Container 2 Sealed Seam 3 Sealed Fin 5 Hanging Piece 7 Intersection 10 Opening Strip Piece 11 Carrier Layer 12, 13 Outer Cover 14 Inner Layer 15 Outer Layer

Claims (7)

[Claims] 1. An opening device for a packaging container (1) made of a plastic-coated packaging material, which is used as a container wall (4).
Having a sealing fin (3) extending laterally above, the plastic coatings (12) of the facing packaging material layers in the sealing fin are joined to one another as a sealing seam, said packaging material layer being at least of the sealing fins. An outer layer (15) of material that fits along a portion of the tear strip (10) embedded in the sealing fin, the tear strip sealingly adhered to the plastic coating (12) of the packaging material. In an opening device consisting of an inner layer (14) sandwiched between two), said opening strip (10) is between its inner layer (14) and each corresponding outer layer (15). An intermediate layer (16) in which the material of the intermediate layer is between all material layers contained within the tear strip and between the outer layer (15) of the tear strip and the plastic coating (12) of the packaging material. The adhesive bond strength between the intermediate layer (16)
An opening device having a property of being greater than the inner adhesive bond strength of the above. 2. The opening device according to claim 1, wherein the intermediate layer (16) of the opening strip (10) comprises a physical mixture of polythene and polybutene. 3. The intermediate layer (16) of the tear strip (10) is 1
The opening device according to claim 2, comprising between 0% and 50% by weight of polybutene. 4. The plastic coating (12) of the packaging material and the outer layer (15) of the tear strip consist of polythene, and the tear strip (10) comprises a plastic coating (12) of the packaging material and the strip. 4. An unsealing device as claimed in claim 2 or 3, which is connected to the packaging material layer by surface fusion with the outer layer of the unsealing strip in the area of the part of the sealing fin (3) which is fitted with 5. The unsealing device as claimed in claim 1, wherein the inner layer (14) of the unsealing strip is made of a material having high tensile strength and tear resistance. 6. The unsealing device according to claim 5, wherein the inner layer (14) of the unsealing strip is made of polyester, polypropylene or oriented polypropylene, preferably polyester. 7. The opening device according to claim 6, wherein the inner layer (14) of the tear strip is subbed to provide good adhesion between the inner layer and the corresponding intermediate layers (16). .