KR20240040763A - Tear-release strips and methods for manufacturing tear-release strips for packaging - Google Patents

Abstract

The invention relates to a tear-release strip (10) for packaging (28) comprising a paper substrate (14) and a layer system (12) with an adhesive layer (16) arranged on a first side of the paper substrate (14). . The adhesive layer 16 has an uneven surface structure with relative elevations 20 and relative depressions 22 in at least some areas. The invention also relates to a method for manufacturing such tear-release strips (10).

Description

Tear-release strips and methods for manufacturing tear-release strips for packaging

The present invention relates to tear-open strips for packaging, methods for making such tear-open strips, and packaging having such tear-open strips.

Tear-release strips for packaging are known in the prior art and serve to facilitate opening of sealed packaging. However, tear-release strips are currently mainly composed of plastic, which poses environmental protection and recycling problems. Thus, there have already been first attempts to produce paper-based compostable or biodegradable tear-release strips.

However, this situation is considered disadvantageous in that these paper-based tear-release strips exhibit substantially inferior opening behavior to previous plastic-based tear-release strips, which are difficult to open by tearing. This is because the packaging is often torn and not partially opened or only partially opened.

Accordingly, the object of the present invention is to provide a paper-based tear-open strip with improved tear-open behavior. A further object is to provide a method for manufacturing such tear-release strips. Finally, a further object is to provide packaging with such a tear-release strip.

According to the invention, this object is solved by a tear-release strip with the features of claim 1, a method for producing such a tear-release strip with the features of claim 9, as well as packaging according to claim 15. Configurations with convenient deployment are described in the dependent claims, and advantageous configurations of each inventive aspect are to be regarded as advantageous configurations of each other inventive aspect.

A first aspect of the invention is a tear-release strip for packaging comprising a layer system comprising a paper substrate and an adhesive layer arranged on the first side of the paper substrate. It's about. According to the invention, improved tear-opening behavior is achieved in that the adhesive layer comprises an uneven surface structure with relative elevations and relative depressions in at least some areas. That is, according to the present invention, a paper-based tear-release strip is provided, wherein the adhesive layer has relative elevations (“peaks”) and relative depressions (valleys, wells) in some areas or in a complete manner. )) and has an uneven surface structure. Without wishing to be bound by this theory, the inventors assume that the improved tear-open behavior is achieved by an uneven surface structure, since the tear-release strip may adhere differently and strongly locally to the associated packaging. This is because depressions or valleys locally weaken the adhesion, while ridges or peaks result in a tighter and more robust bonding connection, resulting in a more robust adhesion. When the package is torn open, local weakening of the adhesive joints prevents the paper-based tear-release strips from sticking too tightly and tearing. However, the ridges at the same time reliably prevent a general weakening of the adhesion to the relevant packaging. Preferably, the adhesive layer comprises 20 to 100 ridges per square centimeter of the paper substrate. 40 to 60 ridges, especially about 50 ridges per square centimeter, are particularly preferred. Basically, the adhesive layer may consist of one or more suitable adhesives and may optionally contain additives. For example, adhesives based on poly(meth)acrylate, natural or synthetic rubber and/or sealing wax may be used. In general, “a/one” should be construed as an indefinite article within the scope of the present disclosure, and therefore should always be construed as “at least a/at least one” without explicit indication to the contrary. Conversely, “a/one” can also be understood as “only a/only one.”

In an advantageous configuration of the invention, it is provided that the paper substrate is compostable and/or biodegradable. This achieves improved environmental balance. Alternatively or additionally, the paper substrate may have a weight of 80 g/m2 to 200 g/m2, especially 100 g/m2. Provided is a mass of the compound ranging from about 140 g/m2, especially about 120 g/m2. This ensures sufficient stability of the paper substrate and thus advantageous sealing and tear-opening behavior of the tear-release strip for most application cases and embodiments. Particularly preferably, the application amount of adhesive per unit area of the paper substrate is selected depending on or as a function of the mass of the compound of the paper substrate, with generally higher application amounts per unit area being selected for higher masses of the compound. In this way, reliable closing of the packaging on the one hand and reliable tear-opening behavior without premature tearing or decomposition of the tear-opening strip on the other can be ensured. Alternatively or additionally, in that it has a stability of at least 75 N/15 mm, preferably at least 110 N/15 mm, in the direction of main extension of the paper substrate, and/or a thickness of 100 μm to 250 μm, especially 150 μm to 200 μm. Favorable sealing and opening behavior of the tear-release strip is ensured. The main direction of extension means the direction of the longest extension of the opened strip, i.e. the direction of extension in which the associated packaging is generally torn and opened.

A further advantage arises in that the first and/or second side of the paper substrate is embossed and/or bleached and/or dyed and/or printed. Thereby, the tear-release strip can be easily adapted, especially optically and/or functionally, to different requirement profiles. For example, an embossed paper substrate can influence better non-adhesive properties of the non-adhesive second side.

In a further advantageous configuration of the invention, it is provided that the adhesive layer is applied over the entire first side or partially. That is, either the entire surface of the paper substrate is provided with an adhesive layer or only one or more surface areas are provided. This allows control of adhesion and tear-opening behavior. Alternatively or additionally, advantageous tear-opening behavior is achieved in that the adhesive layer has an application weight of 15 g/m 2 to 60 g/m 2 , in particular 20 g/m 2 to 30 g/m 2 . In a further configuration, the adhesive layer has a regular surface structure, in particular a dot structure and/or a wave structure and/or a line structure and/or a pyramid structure and/or a truncated pyramid. Advantageous tear-opening behavior is achieved in that it has a truncated pyramid structure and/or a hexagonal structure and/or a line structure with wells and/or a calotte structure. Accordingly, the ridges and depressions of the surface structure comprise regularly arranged structural elements, where only a single structural element type or two or more structural element types may be present. For multiple structural element types, they can usually have identical or different volumes.

A further improved tear-opening behavior arises in that the surface structure of the adhesive layer comprises, at least in some areas, periodic structural elements, wherein at least one extension vector of the periodicity of the structural elements is preferably It is arranged obliquely with respect to the main extending direction of the substrate. That is, the extension vectors of the periodicity of the structural elements are not arranged parallel or coaxial, but are provided at angular positions other than 0° and 180°, respectively, with respect to the main extension direction of the paper substrate. When tearing open the tear-release strip, the forces generated therein are advantageously deflected and better distributed, so that tear-opening of the tear-release strip is particularly reliably prevented.

In a further advantageous configuration of the invention, it is provided that the separation layer is arranged over the entire second side of the paper substrate or in several zones, wherein the applied weight of the separation layer is preferably between 0.1 g/m 2 and 2.0 g/m 2 , especially 0.2 g/m2 to 1.0 g/m2. This reliably prevents the tear-release strip from clogging or sticking to itself, for example when winding up. The separation layer may be formed on the basis of silicone, other separation layers based on polyacrylate, carbamate, polyvinyl ether wax or other suitable compounds, as well as mixtures thereof. may also be provided by default.

Alternatively or additionally, it has proven advantageous for the separating strips to be arranged on the side of the adhesive layer opposite the paper substrate. This also offers the possibility of preventing the tear-release strip from clogging or sticking to undesirable areas of itself or the associated packaging. For example, the separation strip may be a separation foil or a separation paper, for example silicone paper.

In a further configuration, advantageous storage or advantageous transportation of the tear-open strip is achieved in that it is preferably wound on reels with traversing windings and/or packaged as a flat reel.

A second aspect of the invention relates to a method for producing tear-release strips for packaging, wherein a layer system is produced in which an adhesive layer is applied to the first side of a paper substrate. According to the invention, improved tear-opening behavior is achieved in that an adhesive layer is produced which has an uneven surface structure with relative elevations and relative depressions at least in some areas. The advantages arising from this can be obtained from the description of the first inventive aspect, where advantageous configurations of the first inventive aspect are regarded as advantageous configurations of the second inventive aspect. Conversely, advantageous configurations of the second aspect of the invention should also be considered advantageous configurations of the first aspect of the invention. After production, the tear-open strips can be wound onto reels using transversal windings, which allows large operating lengths of up to 40,000 m or longer, typically 10,000 - 20,000 m. Alternatively, tear-release strips may be packaged in flat reels.

In an advantageous arrangement of the invention, it is provided that the paper substrate is provided with an uneven surface structure before applying the adhesive layer and/or that the uneven surface structure is created in the adhesive layer. Thus, an uneven surface structure of the adhesive layer can be achieved in that the adhesive layer itself is applied correspondingly unevenly to a paper substrate, which generally has a uniform surface in at least some areas. However, alternatively or additionally, it may be provided that the paper substrate is first provided with a non-uniform surface at least in some areas, and then the adhesive layer is applied uniformly or non-uniformly to the paper substrate. Here, the first side and/or the second side of the paper substrate may generally have a non-uniform surface. Here, soft paper substrates are generally simpler to coat than rough or structured substrates.

In a further advantageous configuration of the invention, it is provided that the adhesive layer is applied to the paper substrate by an anilox roll, in particular a hachure roll. This allows applying an adhesive layer to a paper substrate with a defined local adhesive dosage thereby creating a defined surface structure with predetermined elevations and depressions. In addition to the geometry of the structural element or elements forming the surface structure, the local application volume of the adhesive layer can be precisely controlled by appropriate selection of the wells and ridges of the anilox roll, respectively.

A further advantage arises in that the paper substrate is provided with a printing layer and/or a separation layer on the second side. With the help of the printing layer, the visual impression of the tear-release strip can be adjusted. Additionally, the tear-release strip may be provided with symbols or indications of use. Printing may generally be performed by gravure printing, flexographic printing, offset printing, laser printing, inkjet printing or other suitable printing methods. Printing inks may be based on nitrocellulose (NC), polyurethane (PU), polyvinylchloride (PVC), polyvinyl butyral (PVB), or other binders. . The separation layer prevents the tear-release strip from sticking undesirably to itself, for example.

Here, it is added that it is advantageous if a varnish layer is applied between the printing layer and the separating layer, since in this way the printing layer is particularly simply protected against damage and optionally a further improved visual impression can be provided. It has been proven.

Given that the tear-release strip is cut into multiple strips, preferably by scissors cuts, the width of the tear-release strip can be adjusted to suit different application purposes, and the manufacture of the tear-release strip first begins with this width. It can be carried out in multiples of , which facilitates the coating process or the layer system formation process. Preferably, the tear-open strip has a width after cutting of 2 mm to 15 mm, especially 4 mm to 8 mm.

A third aspect of the invention relates to packaging comprising at least one tear-release strip formed according to the first aspect of the invention and/or produced by a method according to the second aspect of the invention. The advantages resulting from this can be obtained from the description of the first and second aspects of the invention, where advantageous configurations of the first and second aspects of the invention are to be regarded as advantageous configurations of the third aspect of the invention. Conversely, advantageous configurations of the third inventive aspect should also be considered advantageous configurations of the first and second inventive aspects. Preferably, the packaging can be configured to be fully compostable or biodegradable. Additionally, the package may include two or more tear-release strips.

Additional features of the invention will become apparent from the claims, drawings and description of the drawings. The features and combinations of features mentioned in the above description, as well as the features and combinations of features mentioned only in the drawing description and/or drawings below, can be used not only in the respective designated combinations but also in other combinations without departing from the scope of the present invention. . Accordingly, implementations should also be considered to be encompassed and disclosed by the invention, which may arise and be created from combinations of features not explicitly shown or described in the drawings but separate from the described implementations. Implementations and functional combinations should also be considered disclosed and therefore do not include all of the functionality of the originally written independent claims. Additionally, implementations and functional combinations should be considered as specifically disclosed by the above-described implementations, which extend beyond or depart from the functional combinations described in connection with the claims. The following is displayed:

1 is a schematic cross-sectional view of a tear-release strip according to the invention;
Figure 2 is a schematic partial top view of a tear-open strip according to the invention during application of the adhesive layer;
Figure 3 is a schematic perspective view of a tear-open strip reel;
Figure 4 is a top view of the package with the tear-release strips arranged;
Figure 5 is an enlarged view of detail V shown in Figure 4.

Figure 1 shows a schematic cross-section of a tear-release strip 10 according to the invention. The tear-release strip 10 comprises a layer system 12 , in this case a paper substrate 14 , an adhesive layer 16 arranged on a first side of the paper substrate 14 and a layer of the paper substrate 14 . It comprises an essentially optional separating layer 18 arranged on the second side. The cross-section shows that the adhesive layer 16 includes an uneven surface structure with a wave-like structure of relative elevations 20 and relative depressions 22.

The tear-release strip 10 shown is compostable and/or biodegradable. Typically, the paper substrate 14 is formed based on cellulose. However, other paper types (e.g. PET fiber based paper) may also be available. The mass of the compound of the paper substrate 14 is 90 to 200 g/m 2 , for example 120 g/m 2 . The paper substrate 14 may be white, bleached, unbleached, or dyed. Similarly, the paper substrate 14 may be provided printed on one or both sides. The paper substrate 14 has a high mechanical stability in the main direction of extension H (see Figure 2) or in the operating direction of at least 75 N/15 mm, in particular at least 110 N/15 mm or more. As can be seen in Figure 1, the paper substrate 14 is smooth, allowing for excellent coating capabilities. However, it can also be provided that the paper substrate 14 basically comprises a structured surface on the first and/or second side to which the adhesive layer 16 and/or the separation layer 18 are applied. By embossing the paper substrate 14, better non-stick properties of the non-adhesive second side can often be achieved.

In this case, the adhesive layer 16 is applied to the entire first surface of the paper substrate 14, but is basically applicable only to some areas. As can be seen in Figure 2, which shows a schematic and partial top 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 regular lines or waves. It includes a structure formed by lines or waves formed by the ridges 20 as structural elements. The wave or line structures shown can be produced, for example, by corresponding gravure of a coating cylinder, for example by a Hachure roll. Additionally, as can be seen in FIG. 2 , the line structure with elevations 20 and depressions 22 is formed regularly because the lines are periodically repeated on the surface of the paper substrate 14 . Additionally, the extension vector V of the periodicity of the line structural elements is arranged obliquely with respect to the main extension direction H of the paper substrate 14 . That is, the lines or ridges 20 do not extend perpendicular or parallel to the main extension direction H, but extend diagonally. However, instead of the basic line-shaped or wave-shaped surface structure, other regular or irregular surface structures (patterns) can also be created.

As the adhesive layer 16, polyacrylate-based adhesive, natural or synthetic rubber, or sealing wax can be used. The adhesive application range is generally between 15 and 60 g/m2, especially 20 to 30 g/m2.

Separation layer 18 may also be applied to the entire paper substrate 14 or only to specific surface areas. The separating layer 18 is usually based on silicone, but other separating agents are based for example on polyacrylates, carbamates or polyvinyl ether waxes. It can also be used generally. The applied weight of the separation layer 18 is normally in the range of 0.1 to 2.0 g/m2, especially 0.2 to 1.0 g/m2.

Alternatively, the separation layer 18 may be omitted and the adhesive layer 16 may instead be covered with a separation foil (not shown) or a separation paper, for example silicone paper.

Alternatively, the paper substrate 14 may be printed, especially on a non-adhesive side. If a separation layer 18 is provided, printing is preferably performed directly on the paper substrate 14 prior to coating with the separation layer 18. Printing may be performed by gravure printing, flexographic printing, offset printing or other printing methods. Printing inks can be based on NC, PU, PVC, PVB or other binders. Optionally, an additional varnish coating (not shown) may be applied between the print layer and the separation layer 18. In this case, the layer composition of the layer system 12 will be adhesive layer 16 - paper substrate 14 - printing layer - varnish layer - separation layer 18.

Figure 3 shows a schematic perspective view of the tear-open strip reel 26. Here, the tear-open strip (10) is wound around the core (24). Here, the tear-open strip 10 is preferably wound in transverse turns, allowing large operating lengths of up to 40,000 m (typically 10,000-20,000 m). Alternatively, the tear-release strip 10 may be packaged as a flat reel. The tear-open strip 10 can be cut into narrower strips. Typical strip widths for the most common packaging 28 are about 2 to 15 mm, especially 4 to 8 mm. Cutting is usually done with scissors, but other cutting or separating types are also possible.

Figure 4 shows a top view of the unfolded packaging 28 on which a further embodiment of the tear-release strip 10 according to the invention is arranged. Figure 4 is schematically explained with Figure 5, showing an enlarged representation of detail V. In particular, it can be seen in Figure 5 that the adhesive layer 16 has a regular dot pattern of dot-shaped elevations 20 and corresponding depressions 22 in the present case.

The parameter values specified in the document to define the process and measurement conditions for characterizing the specific properties of the subject matter of the invention shall be determined within the range of deviations caused by, for example, measurement errors, systematic errors, weighing errors, DIN tolerances, etc. considered to be within scope.

10 Tear-opening strips
12 layer system
14 Paper substrate
16 adhesive layer
18 separation layer
20 ridges
22 depression
24 cores
26 tear-open strip reel
28 packaging
H main extension direction
V extension vector

Claims (15)

Packaging comprising a layer system (12) comprising a paper substrate (14) and an adhesive layer (16) arranged on a first side of the paper substrate (14) 28) In the tear-open strip (10),
The tear-open strip, characterized in that the adhesive layer (16) comprises an uneven surface structure with relative elevations (20) and relative depressions (22) at least in some areas. (10). According to claim 1,
The paper substrate 14 is compostable and/or biodegradable and/or the paper substrate 14 contains a compound of 80 g/m2 to 200 g/m2, especially 100 g/m2 to 140 g/m2. and/or the paper substrate 14 has a stability of at least 75 N/15 mm, preferably at least 110 N/15 mm, and/or between 100 μm and 250 μm in the main direction of extension (H). Tear-open strip (10), characterized in particular by having a thickness of 150 μm to 200 μm. The method of claim 1 or 2,
Characterized in that the first and/or second side of the paper substrate (14) is embossed and/or bleached and/or dyed and/or printed. Opening strip (10). The method according to any one of claims 1 to 3,
The adhesive layer (16) is applied over the entire first side or in several zones and/or the adhesive layer (16) has an application weight of 15 g/m2 to 60 g/m2, in particular 20 g/m2 to 30 g/m2, and /or the adhesive layer 16 has a regular surface structure, in particular a dot structure and/or a wave structure and/or a line structure and/or a pyramid structure and/or A tear-open strip, characterized in that it comprises a truncated pyramid structure and/or a hexagonal structure and/or a line structure with wells and/or a calotte structure. (10). According to claim 4,
The surface structure of the adhesive layer 16 comprises, at least in some areas, a periodic structural element, the periodicity of which at least one extension vector V preferably corresponds to the paper substrate 14 The tear-open strip (10), characterized in that it is arranged obliquely with respect to the main direction of extension (H). The method according to any one of claims 1 to 5,
The separation layer 18 is arranged over the entire second side of the paper substrate 14 or in several zones, the applied weight of the separation layer 18 preferably being between 0.1 g/m2 and 2.0 g/m2, especially Tear-release strip (10), characterized in that 0.2 g/m2 to 1.0 g/m2. The method according to any one of claims 1 to 6,
Tear-release strip (10), characterized in that a separation strip is arranged on the side of the adhesive layer (16) opposite the paper substrate (14). The method according to any one of claims 1 to 7,
Tear-open strip (10), characterized in that it is wound on a reel (26), preferably using a traversing winding, and/or packaged in a flat reel. A method for producing a tear-release strip (10) for packaging (28), wherein a layer system (12) is produced in which an adhesive layer (16) is applied to the first side of a paper substrate (14), comprising:
Characterized in that the adhesive layer (16) is produced with an uneven surface structure with relative elevations (20) and relative depressions (22) at least in some areas. According to clause 9,
The method, characterized in that the paper substrate (14) is provided with an uneven surface structure before applying the adhesive layer (16) and/or an uneven surface structure is produced in the adhesive layer (16). According to claim 9 or 10,
Characterized in that the adhesive layer (16) is applied to the paper substrate (14) by an anilox roll, in particular a hachure roll. The method according to any one of claims 9 to 11,
Characterized in that the paper substrate (14) is provided with a printing layer and/or a separation layer (18) on the second side. According to claim 12,
Characterized in that a varnish layer is applied between the printing layer and the separation layer (18). The method according to any one of claims 9 to 13,
Characterized in that the tear-open strip (10) is cut into multiple strips, preferably by scissors cut, the strips having a width preferably between 2 mm and 15 mm, in particular between 4 mm and 8 mm. . Comprising at least one tear-open strip (10) formed according to any one of claims 1 to 8 and/or produced by a method according to any one of claims 1 to 14. Packaging (28).