Tear-open strip for packaging and method for producing tear-open strip - Patents.com

Abstract

The present invention relates to a tear-open strip (10) for a package (28), comprising a layer system (12) having a paper substrate (14) and an adhesive layer (16) disposed on a first side of the paper substrate (14), the adhesive layer (16) having, at least in predetermined areas, a non-flat surface structure including relative protuberances (20) and relative recesses (22). The present invention further relates to a method for producing such a tear-open strip (10).

Description

[Technical field]

[0001] The present invention relates to a tear-open strip for packaging, to a method for producing such a tear-open strip, as well as to a packaging provided with such a tear-open strip.

[0002] Tear strips for packaging are known in the prior art and serve to facilitate the opening of sealed packages. However, today, tear strips are mainly made of plastic, which is problematic for environmental protection and recycling reasons. Therefore, first attempts have already been made to produce paper-based compostable or biodegradable tear strips.

[0003] However, a drawback of this paper-based tear-open strip is that it exhibits significantly inferior tear-opening behavior to conventional plastic-based tear-open strips, as the paper-based tear-open strips often tear when opened and the package is often not opened or only partially opened.

[0004] It is therefore an object of the present invention to provide a paper-based tear-open strip with improved tear-opening behavior. A further object is to provide a method for producing such a tear-open strip. Finally, it is a further object to provide a package with such a tear-open strip.

[0005] This problem is solved according to the invention by a tear-open strip with the features of claim 1, a method for producing such a tear-open strip with the features of claim 9, and a packaging according to claim 15. Advantageous configurations with expedient developments are recited in the dependent claims, advantageous configurations of each inventive aspect being to be regarded as advantageous configurations of the respective further inventive aspects.

[0006] A first aspect of the invention relates to a tear-open strip for packaging, comprising a layer system with a paper substrate and an adhesive layer arranged on a first side of the paper substrate. An improved tear-open behavior is obtained according to the invention because the adhesive layer has, at least in certain areas, a non-flat surface structure comprising relative ridges and relative depressions. In other words, according to the invention, a paper-based tear-open strip is provided in which the adhesive layer has, in certain areas or over the entire surface, a non-flat surface structure comprising relative ridges ("high points") and relative depressions (valleys, cells). Without wishing to be bound by this theory, the inventors postulate that an improved tear-open behavior is achieved by this non-flat surface structure, because this allows the tear-open strip to be locally adhered to the assigned package with different strengths, since the depressions or valleys result in localized weakening of the adhesion, while the ridges or high points result in a closer material-connecting bond and thus a more solid adhesion. In this case, the paper-based tear strip is prevented from being strongly adhered and torn off when the package is torn open by the local weakening of the adhesive bond. At the same time, however, the ridges ensure that an overall excessively weak bond to the assigned package is prevented. Preferably, the adhesive layer has 20 to 100 ridges per square centimeter of paper substrate. 40 to 60, in particular about 50 ridges per square centimeter, are particularly suitable. The adhesive layer may essentially consist of one or more suitable adhesives, possibly containing additives. For example, adhesives based on poly(meth)acrylates, natural or synthetic rubbers and / or sealing lacquers can be used. In general, "one" should be read as an indefinite article within the scope of the present disclosure, i.e., always as "at least one", unless expressly stated to the contrary. Conversely, "one" may also be understood as "only one".

[0007] In an advantageous configuration of the invention, it is envisaged that the paper substrate is compostable and / or biodegradable, thereby achieving an improved environmental balance. Alternatively or additionally, the paper substrate is preferably 80 g / m 2 ~200g / m 2 , especially 100 g / m 2 ~140g / m 2 , especially about 120 g / m 2 It is assumed that the paper substrate has a basis weight of 100 N / 15 mm. This ensures sufficient stability of the paper substrate and thus favorable sealing and tear-opening behavior of the tear-opening strip in the main use cases and embodiments. Particularly preferably, the adhesive application amount per unit area of ​​the paper substrate is selected depending on or as a function of the basis weight of the paper substrate, where for higher basis weights, generally higher application amounts per unit area are selected. This ensures, on the one hand, a secure closure of the package and, on the other hand, a secure tear-opening behavior of the tear-opening strip without pre-breaking or tearing. Alternatively or additionally, the paper substrate has a stability of at least 75 N / 15 mm, preferably at least 110 N / 15 mm, in the main direction of extension and / or a thickness of 100 μm to 250 μm, in particular 150 μm to 200 μm, which ensures favorable sealing and tear-opening behavior of the tear-opening strip. By main direction of extension is understood the direction of the longest extension of the tear-open strip, ie the extension along which tear-open of the assigned package usually takes place.

[0008] Further advantages are obtained by the first and / or second side of the paper substrate being embossed and / or bleached and / or colored and / or printed, which allows the tear-open strip to be particularly easily adapted visually and / or functionally to various required profiles. For example, with an embossed paper substrate, better anti-adhesive properties of the non-adhesive second side can be achieved.

[0009] In a further advantageous configuration of the present invention, it is provided that the adhesive layer is applied to the first side over the entire surface or in a certain section. In other words, it is provided that the entire surface of the paper substrate is provided with an adhesive layer or that only one or more surface areas are provided with an adhesive layer. This allows the adhesive behavior and the tear-open behavior to be controlled. Advantageous tear-open behavior is alternatively or additionally provided when the adhesive layer is 15 g / m 2 ~60g / m 2 , especially 20 g / m 2 ~30g / m 2 In another embodiment, a particularly uniform tear-open behavior is achieved by the adhesive layer having a regular surface structure, in particular dot structures and / or wave structures and / or line structures and / or pyramidal structures and / or truncated pyramidal structures and / or hexagonal structures and / or line structures with cells and / or ball-cap structures. The projections and recesses of the surface structure thus have regularly arranged structural elements, which may be provided with only one structural element type or with two or more structural element types. In the case of several structural element types, these structural element types may generally have the same or different volumes.

[0010] A further improved tear-open behavior is obtained because the surface structure of the adhesive layer has periodic structural elements at least in certain regions, and at least one extension vector of the periodicity of these structural elements is preferably arranged obliquely to the main extension direction of the paper substrate. In other words, the extension vector of the periodicity of the structural elements is not parallel or coaxial to the main extension direction of the paper substrate, but is arranged at an angle position that is not 0° or 180°. In this case, the forces that occur during tear-opening of the tear-open strip are advantageously deflected and distributed better, so that the tear-open strip is particularly reliably prevented from breaking.

[0011] In another advantageous embodiment of the invention, a separating layer is arranged on the second side of the paper substrate over the entire surface or in selected sections, the coating weight of the separating layer being preferably less than 0.1 g / m 2~2.0g / m 2 , especially 0.2 g / m 2 ~1.0g / m 2 It is assumed that the tear strip is preferably formed of a silicone-based material, which can be used to reliably prevent the tear strip from blocking or adhering to itself, for example when winding up. The separating layer can be formed on a silicone basis, in which case it is also possible to provide a further separating layer which is essentially based on polyacrylates, carbamates, polyvinyl ether waxes or other suitable compounds and mixtures thereof.

[0012] Alternatively or additionally, it has been shown to be advantageous to arrange a separation strip on the side of the adhesive layer opposite the paper substrate. This also provides a means for preventing blocking or adhesion of the tear strip itself or the assigned package to undesired areas. The separation strip can be, for example, a separation film or a separation paper, for example silicone paper.

[0013] In another embodiment, advantageous storage or advantageous transport of the tear-open strip is achieved in that the tear-open strip is wound on a bobbin, preferably by traverse winding, and / or is configured as a record-wound bobbin.

[0014] A second aspect of the invention relates to a method for producing a tear-open strip for packaging, which comprises applying an adhesive layer onto a first side of a paper substrate to produce a layer system. Improved tear-open behavior is obtained according to the invention by producing the adhesive layer to have a non-flat surface structure, at least in certain areas, which comprises relative elevations and relative depressions. The resulting advantages are clear from the description of the first aspect of the invention, in which case advantageous configurations of the first aspect of the invention can also be considered as advantageous configurations of the second aspect of the invention. Conversely, advantageous configurations of the second aspect of the invention can also be considered as advantageous configurations of the first aspect of the invention. After production, the tear-open strip can be wound by traverse winding onto a bobbin which allows large working lengths of up to 40,000 m or more, typically between 10,000 m and 20,000 m. Alternatively, the tear-open strip can be configured as a record-wound bobbin.

[0015] In an advantageous configuration of the invention, it is provided for the paper substrate to be provided with an uneven surface structure before the application of the adhesive layer and / or for the adhesive layer to be produced with an uneven surface structure. That is to say, as a rule, the uneven surface structure of the adhesive layer is obtained in that the adhesive layer itself is applied correspondingly unevenly onto a paper substrate having a uniform surface at least in certain regions. However, alternatively or additionally, it may also be provided for the paper substrate to first be provided with an uneven surface at least in certain regions, and then the adhesive layer is applied uniformly or unevenly onto the paper substrate. In this case, basically, the first side and / or the second side of the paper substrate may have an uneven surface. In this case, a smooth paper substrate can usually be coated more easily than a rough or structured paper substrate.

[0016] In a further advantageous embodiment of the invention, it is provided that the adhesive layer is applied to the paper substrate by an anilox roll, in particular a hatching roll, so that the adhesive layer can be applied to the paper substrate with a defined local metering of adhesive, and thus a defined surface structure with defined ridges and recesses can be produced. In addition to the geometry of the structural elements that form the surface structure, the local application volume of the adhesive layer can also be precisely controlled by a suitable selection of the cells or ridges of the anilox roll.

[0017] Further advantages are obtained by providing the second side of the paper substrate with a printing layer and / or a separation layer. By means of a printing layer, the visual impression of the tear-tear strip can be adapted. Furthermore, the tear-tear strip can thereby be provided with symbols or use instructions. The printing can generally be carried out by intaglio, flexographic, offset, laser, inkjet or other suitable printing methods. The inks can be based on nitrocellulose (NC), polyurethane (PU), polyvinyl chloride (PVC), polyvinyl butyral (PVB) or other binders. The separation layer prevents undesired adhesion of the tear-tear strip, for example to itself.

[0018] In this case, it has been found to be further advantageous if a paint layer is applied between the printing layer and the separating layer, since in this way the printing layer can be particularly easily protected against damage and, if necessary, an additional improved visual impression can be achieved.

[0019] By cutting the tear-open strip into strips, preferably by shear cutting, the width of the tear-open strip can be adapted to various applications, and the tear-open strip may initially be produced to have several times this width, which facilitates the coating process to form the layer system. Preferably, the tear-open strip has a width of 2 mm to 15 mm, in particular 4 mm to 8 mm, after cutting.

[0020] The third aspect of the present invention relates to a package comprising at least one tear-open strip formed as in the first aspect of the present invention and / or produced by the method according to the second aspect of the present invention. The advantages resulting from this are clear from the description of the first and second aspects of the present invention, in which case advantageous configurations of the first and second aspects of the present invention can also be considered as advantageous configurations of the third aspect of the present invention. Conversely, advantageous configurations of the third aspect of the present invention can also be considered as advantageous configurations of the first and second aspects of the present invention. The package can preferably be formed to be fully compostable or biodegradable. Furthermore, the package can comprise two or more tear-open strips.

[0021] Further features of the invention are described in the claims, the drawings and the description of the drawings. The features and combinations of features mentioned above in this specification and the features and combinations mentioned below in the description of the drawings and / or shown only in the drawings can be used in other combinations without departing from the scope of the invention, not only in the respective combinations shown. Thus, embodiments that are not explicitly shown and described in the drawings, but which are obvious and can be formed from the described embodiments by combinations of separate features, should also be considered to be included or disclosed by the present invention. Also, embodiments and combinations of features should be considered to be disclosed, and therefore these embodiments and combinations of features do not have all the features of the originally described independent claims. Moreover, particularly the above-mentioned embodiments should be considered to have disclosed embodiments and combinations of features that are more than or different from the combinations of features described in the recitation of the claims. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view showing a tear-open strip according to the present invention; [Diagram 2] 1 shows a schematic partial plan view of a tear-open strip according to the invention during application of the adhesive layer; [Diagram 3] FIG. 2 is a perspective view showing a schematic view of a tear-open strip bobbin. [Figure 4] FIG. 2 is a plan view showing a package having a tear-open strip disposed thereon. [Diagram 5] FIG. 5 is an enlarged view of detail V shown in FIG. 4.

[0023] 1 shows a schematic cross-sectional view of a tear-open strip 10 according to the invention, which in this embodiment comprises a layer system 12 having a paper substrate 14, an adhesive layer 16 arranged on a first side of the paper substrate 14 and essentially a separating layer 18, which is optionally arranged on a second side of the paper substrate 14. From this cross-sectional view it can be seen that the adhesive layer 16 has a non-flat surface structure with a corrugated structure consisting of relative ridges 20 and relative recesses 22.

[0024] The illustrated tear-open strip 10 is compostable and / or biodegradable. Typically, the paper substrate 14 is cellulose-based. However, other types of paper may be provided, for example PET fiber-based paper. The basis weight of the paper substrate 14 is between 90 and 200 g / m 2 , e.g. 120g / m 2 The paper substrate 14 may be white or bleached, unbleached or colored. It may also be envisaged that the paper substrate 14 is printed on one or both sides. The paper substrate 14 has a high mechanical stability of at least 75 N / 15 mm, in particular at least 110 N / 15 mm or more, in the main extension direction H (see FIG. 2) or in the running direction. As shown in FIG. 1, the paper substrate 14 is smooth in order to allow good coverage. In principle, however, it may also be envisaged that the first and / or second side of the paper substrate 14 has a structured surface, on which the adhesive layer 16 and / or the separating layer 18 are applied. By embossing the paper substrate 14, better anti-adhesive properties of the non-adhesive second side can often be achieved.

[0025] The adhesive layer 16 is applied over the entire surface of the first side of the paper substrate 14 in this case, although it is also possible to apply only certain areas. As can be seen from FIG. 2, which shows a schematic partial plan view of the tear-open strip 10 according to the invention during application of the adhesive layer 16, the structured surface of the adhesive layer 16 has a regular linear or corrugated structure formed as structural elements by lines or waves formed by the ridges 20. The illustrated corrugated or linear structure can be produced, for example, by corresponding gravure of a coating cylinder, for example a hatching roll. FIG. 2 further shows that the linear structure with the ridges 20 and the depressions 22 is formed regularly, since these lines are repeated periodically on the surface of the paper substrate 14. In addition, the extension vector V of the periodicity of the linear structural elements is arranged obliquely with respect to the main extension direction H of the paper substrate 14. In other words, the lines or ridges 20 do not extend perpendicularly or parallel to the main extension direction H, but diagonally. Basically, instead of linear or wavy surface structures, other regular or irregular surface structures (patterns) may also be produced.

[0026] For the adhesive layer 16, polyacrylate-based adhesives, natural or synthetic rubber or sealing lacquers can be used. The adhesive application is typically between 15 and 60 g / m 2 In particular, it is in the range of 20 to 30 g / m 2 It is.

[0027] The separating layer 18 may also be applied over the entire surface or only to selected surface areas of the paper substrate 14. The separating layer 18 is typically silicone-based, although other separating means may also be used, typically based on, for example, polyacrylate, carbamate or polyvinyl ether waxes. The coating weight of the separating layer 18 is typically between 0.1 and 2.0 g / m 2 In particular, the range of 0.2 to 1.0 g / m 2 is in the range.

[0028] Alternatively, the release layer 18 can be omitted and instead the adhesive layer 16 can be covered with a release film (not shown) or paper, such as silicone paper.

[0029] Optionally, the paper substrate 14 can be printed, in particular on the non-adhesive side. If a separation layer 18 is provided, printing is preferably carried out directly on the paper substrate 14 before applying the separation layer 18. Printing can be carried out by intaglio, flexography, offset printing or another printing method. The inks can be based on NC, PU, ​​PVC, PVB or other binders. Optionally, an additional paint coating (not shown) can be applied between the printing layer and the separation layer 18. The layer structure of the layer system 12 is in this case adhesive layer 16 - paper substrate 14 - printing layer - paint layer - separation layer 18.

[0030] FIG. 3 shows a schematic perspective view of a tear-open strip bobbin 26. The tear-open strip 10 is wound for this purpose on a core 24. Preferably, the tear-open strip 10 is wound in this case in a traverse winding, which allows large working lengths of up to 40,000 m, typically between 10,000 m and 20,000 m. Alternatively, the tear-open strip 10 may be configured as a record-wound bobbin. The tear-open strip 10 can be cut into thinner strips. Typical strip widths for a typical package 28 are approximately 2 to 15 mm, in particular 4 to 8 mm. The cutting is typically performed by shear cutting, although other types of cutting or separation are also possible.

[0031] Figure 4 shows a plan view of an unfolded package 28, on which another embodiment of a tear-open strip 10 according to the invention is arranged. Figure 4 is explained together with Figure 5, which shows an enlarged view of detail V. In particular, Figure 5 shows that the adhesive layer 16 in this case has a regular dot pattern of dot-like raised portions 20 and corresponding recesses 22.

[0032] The parameter values ​​described herein for defining the process and measurement conditions for characterizing the unique properties of the subject matter of the present invention can be considered to be within the scope of the present invention even within ranges of deviation based on, for example, measurement error, systematic error, metrology error, DIN tolerances, etc. [Explanation of symbols]

[0033] 10 Tear-off strip 12-layer system 14 Paper base material 16 Adhesive layer 18 Separation layer 20 Ridge 22 Recess 24 cores 26 Tear-opening strip bobbin 28 Packaging H Main direction of extension V extension vector

Claims

1. A tear-open strip (10) for a packaging (28), comprising a layer system (12) having a paper substrate (14) and an adhesive layer (16) disposed on a first surface of the paper substrate (14). In the tear-open strip, the adhesive layer (16) has a non-planar surface structure including relative protrusions (20) and relative recesses (22) at least in a predetermined region, characterized in that the tear-open strip (10).

2. The paper base material (14) is compostable and / or biodegradable, and / or the paper base material (14) has a basis weight of 80 g / m ２ to 200 g / m ２ , particularly 100 g / m ２ to 140 g / m ２ , and / or the paper base material (14) has a stability of at least 75 N / 15 mm, preferably at least 110 N / 15 mm in the main extension direction (H), and / or has a thickness of 100 μm to 250 μm, particularly 150 μm to 200 μm. The tear-open sealing tape (10) according to claim 1.

3. The first surface and / or the second surface of the paper substrate (14) is embossed and / or bleached and / or colored and / or printed, the tear-open strip (10) according to Claim 1.

4. The adhesive layer (16) is adhered to the entire surface or a predetermined section of the first surface, and / or the adhesive layer (16) has a coating weight of 15 g / m ２ to 60 g / m ２ , particularly 20 g / m ２ to 30 g / m ２ , and / or the adhesive layer (16) has a regular surface structure, particularly a dot structure and / or a corrugated structure and / or a linear structure and / or a pyramid structure and / or a truncated pyramid structure and / or a hexagonal structure and / or a linear structure with cells and / or a spherical crown structure. The tear-openable strip (10) according to claim 1.

5. The surface structure of the adhesive layer (16) has periodic structural elements at least in a predetermined region, and a periodic extension vector (V) of the structural elements is preferably disposed obliquely with respect to a main extension direction (H) of the paper substrate (14), the tear-open strip (10) according to Claim 4.

6. On the second surface of the paper substrate (14), a release layer (18) is disposed over the entire surface or in a predetermined section, and the coating weight of the release layer (18) is preferably 0.1 g / m ２ ~2.0 g / m ２ , particularly 0.2 g / m ２ ~1.0 g / m ２ The tear-openable sealing tape (10) according to claim 1, which is such.

7. A separation strip is disposed on a surface of the adhesive layer (16) opposite to the paper substrate (14), the tear-open strip (10) according to Claim 1.

8. The tear-open strip is wound around a bobbin (26), preferably by traverse winding, and / or is configured as a record winding bobbin, the tear-open strip (10) according to Claim 1.

9. A method for manufacturing a tear-open strip (10) for a packaging (28), comprising manufacturing a layer system (12) by applying an adhesive layer (16) on a first surface of a paper substrate (14). In the method, the adhesive layer (16) is manufactured to have a non-planar surface structure including relative protrusions (20) and relative recesses (22) at least in a predetermined region, characterized in that the method.

10. A non-planar surface structure is provided on the paper substrate (14) before the application of the adhesive layer (16), and / or the non-planar surface structure is generated on the adhesive layer (16), the method according to Claim 9.

11. The adhesive layer (16) is applied on the paper substrate (14) by an anilox roll, particularly a hatching roll, the method according to Claim 9.

12. A printing layer and / or a separation layer (18) is provided on a second surface of the paper substrate (14), the method according to Claim 9.

13. The method according to claim 12, wherein a paint layer is applied between the printing layer and the separation layer (18).

14. The method according to claim 9, wherein the tear-open strip (10) is cut into a plurality of strips, preferably by shear cutting, the strips preferably having a width of from 2 mm to 15 mm, in particular from 4 mm to 8 mm.

15. A packaging (28) comprising at least one tear-open strip (10) formed as claimed in any one of claims 1 to 8 and / or produced by the method according to any one of claims 9 to 14.

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