Method for the production of a coated packaging material

Abstract

The invention relates to a method for producing a coated packaging material (10), in particular a laminate, comprising at least the steps of: providing a cellulose-containing substrate (12) having a first surface (14) and a second surface (16) opposite the first surface (14); coating at least part of a surface region of the first surface (14) of the substrate (12) with at least one sealable substance (18) by means of a printing process, wherein the sealable substance (18) is applied in a pattern, leaving regions (20) not covered with the sealable substance (18); and coating at least part of a surface region of the second surface (16) of the substrate (12) with at least one barrier layer (22) by means of a printing process. The invention also relates to a packaging material and to a packaging which at least partly comprises a packaging material (10).

Description

[0001] Method for producing a coated packaging material

[0002] Description

[0003] The invention relates to a method for producing a coated packaging material, a coated packaging material and a packaging made from such a packaging material.

[0004] Cellulose-based packaging materials are useful in a wide variety of applications. For example, these papers and boards are suitable for the production of gift wrap, packaging cartons, and other types of packaging. Often, it is necessary to provide the packaging material with one or more so-called barrier layers. These serve to protect the packaged goods against potentially harmful environmental influences. Furthermore, it is very often necessary for barrier papers or boards used as packaging materials to be sealable on one or both sides. This sealability ensures a secure seal of the packaged goods, which is crucial for the safe storage of packaged food, for example, in food packaging.

[0005] A disadvantage of known barrier papers and boards, as well as their manufacturing processes, is that the standard coating process with double-sided, full-surface sealing drastically impairs the recycling process ("deinking"). Rewetting the fibers of the cellulosic substrate and thus their recycling are extremely difficult. A double-sided, closed coating of fiber-containing materials (paper / board) therefore reduces the percentage of recyclability of packaging materials in conventional deinking processes. WO 2024 / 025693 A1 discloses multilayer paper-based packaging films that comprise, in addition to the paper component, a polymer film and a patterned, sealable material. The paper-based packaging films can contain additional materials, such as adhesive and / or barrier material. The barrier material can be located between the paper component and the polymer film.The adhesive can attach the polymer film or the barrier material, if present, to the paper component. The recyclability of these well-known packaging films is ensured by a paper content of > 80% by weight. However, a disadvantage of these packaging films is the use of a polymer film as the carrier material. The polymer film must be applied over the entire surface in a separate process step. This slows down the manufacturing process, and the full-surface application of the polymer film to the paper substrate also limits the design and application possibilities of this well-known packaging film.

[0006] The object of the present invention is to improve a generic method for producing a coated packaging material such that, on the one hand, it can be operated at a high process speed and, on the other hand, it produces highly recyclable packaging materials with a wide range of possible uses. Further objects of the present invention are to provide a coated packaging material that can be produced cost-effectively and is highly recyclable, as well as to provide a packaging that consists at least partially of such a packaging material.

[0007] The objects are achieved according to the invention by a method having the features of patent claim 1, by a packaging material having the features of patent claim 15 and by a packaging according to claim 18. Advantageous embodiments with expedient further developments of the invention are specified in the respective subclaims, wherein advantageous embodiments of each aspect of the invention are to be regarded as advantageous embodiments of the respective other aspects of the invention and vice versa.A first aspect of the invention relates to a method for producing a coated packaging material, comprising at least the following method steps: providing a cellulose-containing substrate having a first surface and a second surface opposite the first surface, coating at least part of a surface region of the first surface of the substrate with at least one sealable substance by means of a printing method, wherein the sealable substance is applied in a patterned manner while leaving areas not covered with the sealable substance, and coating at least part of a surface region of the second surface of the substrate with at least one barrier layer by means of a printing method.By using printing processes for coating both the first and second surfaces of the cellulose-containing substrate, the process according to the invention can be carried out at high speed. Time-consuming intermediate steps, such as applying a polymer film by lamination, are no longer necessary. Furthermore, the patterned application of the sealable substance, while leaving areas on the first surface not covered with the sealable substance, ensures that the fibers of the cellulose-containing substrate can be effectively rehydrated during a recycling process for the packaging material. This results in a high percentage (> 95%) of recyclability of the packaging materials produced using the process according to the invention in conventional deinking processes.The cellulosic substrate can be coated or uncoated paper, coated or uncoated board, or coated or uncoated cardboard or corrugated board. The basis weight / grammage of the cellulosic substrate is between 15 g / m². 2 and 450 g / m 2 . Below values ​​between 15 g / m 2 and 450 g / m 2 In particular, grammages of 15 g / m 2 , 20 g / m 2 , 30 g / m 2 , 40 g / m 2 , 50 g / m 2 , 60 g / m 2 , 70 g / m 2 , 80 g / m 2 , 90 g / m 2 , 100 g / m 2 , 110 g / m 2 , 120 g / m 2 , 130 g / m 2 , 140 g / m 2 , 150 g / m 2 , 160 g / m 2 , 170 g / m 2 , 180 g / m 2 , 190 g / m 2 , 200 g / m 2 , 210 g / m 2 , 220 g / m 2 , 230 g / m 2 , 240 g / m 2 , 250 g / m 2 , 260 g / m 2 , 270 g / m 2, 280 g / m 2 , 290 g / m 2 , 300 g / m 2 , 310 g / m 2 , 320 g / m 2 , 330 g / m 2 , 340 g / m 2 , 350 g / m 2 , 360 g / m 2 , 370 g / m 2 , 380 g / m 2 , 390 g / m 2 , 400 g / m 2 , 410 g / m 2 , 420 g / m 2 , 430 g / m 2 , 440 g / m 2 , 450 g / m 2 and corresponding intermediate values. Furthermore, the cellulose-containing substrate can contain at least 10% by weight of recycled cellulose fibers based on the total weight of the substrate. The use of recycled fibers advantageously reduces the consumption of virgin cellulose fibers and thus increases the sustainability of the packaging material produced in this way.

[0008] In further advantageous embodiments of the method according to the invention, the first surface is a surface of the substrate facing away from the product to be packaged with the packaging material. However, it is also possible for the first surface to be a surface of the substrate facing the product to be packaged with the packaging material. This means that the first surface can form an outer or inner surface of the substrate. The inner surface is facing or closer to the product to be packaged or the already packaged product.

[0009] Furthermore, it is possible that when coating the first surface approximately 20 - 90% of the area of ​​the first surface is covered with the sealable substance. Between 20% and 90% is understood to mean values ​​of 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% and corresponding intermediate values. Surprisingly, it has been found that this is sufficient to ensure secure sealing of the packaging material or the goods packaged with it. Since the surface is not completely sealed, the recyclability of the packaging material produced in this way is not impaired. This particularly applies to the possibility of rewetting the fibers of the cellulosic substrate. It is also possible for the second surface to be coated with the barrier layer over its entire surface or part of its area.Even a full-surface coating of the second surface does not impair the recyclability described above, since the first surface provides a pathway for rewetting of the substrate. If the barrier layer is also only applied to partial areas of the second surface, rewetting of the substrate can also occur via the second surface. The type of barrier coating and its application depend on the requirements of the packaging material. The barrier layer can be water- and / or moisture- and / or vapor- and / or grease- and / or oil- and / or gas-repellent. In addition, the barrier layer can provide aroma protection for the packaged product, in particular a food product. Inorganic and / or organic materials known from the prior art are suitable for use in or as a barrier layer.For example, polyethylene (PE) coatings can be used. Polyethylene coatings provide a good moisture barrier. Polyester (PET) coatings also provide a barrier against moisture and gas penetration. Wax-based coatings consist of waxes such as paraffin or carnauba wax and are used for grease-repellent or grease-resistant coatings. Metal coatings are also conceivable as barrier layers. Aluminum coatings, for example, create a very good barrier against moisture, oxygen, light, and aromas. Silicone coatings are also known, which provide a good barrier against moisture and can also be heat-resistant. Other barrier coatings are conceivable and can be applied to the cellulose-containing substrate to coat the packaging material according to the invention according to the method of the invention.These barrier coatings can be used individually or in combination to achieve the desired barrier properties, depending on the requirements of the packaging material. Finally, it is possible for at least the outer, near-surface barrier layer, if at least two different barrier layers are present, to be sealable. This advantageously ensures a secure seal of the packaging produced using the packaging material. In particular, with appropriate folding of the packaging material, the first surface can form a strong bond with the second surface via the respective sealable sections of the two surfaces.

[0010] In further advantageous embodiments of the method according to the invention, at least two different sealable substances are applied to different surface areas when coating the first surface. However, it is also possible for at least two different barrier layers to be applied to different surface areas and / or one above the other in addition to or instead of coating the second surface. Advantageously, the type and distribution of the sealable substances and the barrier layers can be varied depending on the requirements of the packaging material.

[0011] In further advantageous embodiments of the method according to the invention, a printing process from the group consisting of flexographic printing, planographic printing, gravure printing, digital printing, screen printing, embossed printing, and / or offset printing is used to coat the first and second surfaces. By using printing processes for coating both the first and second surfaces of the cellulose-containing substrate, the method according to the invention can be carried out at high speed. Furthermore, the type of printing process can be adapted to the respective requirements of the packaging material to be produced, so that the method according to the invention has a wide range of applications. The term "printing process" also includes application processes from the printing industry, such as roller coating, pour-on coating, slotted nozzle coating, and / or curtain coating.The same applies to so-called coating processes, in which the substance is applied in particular by means of a doctor blade, blade and / or film press.

[0012] Furthermore, it has proven advantageous for the manufacturing process if the viscosity of the sealable substance and the viscosity of the barrier layer are adapted to the type of printing process used, at least during the respective coating process.

[0013] In further advantageous embodiments of the method according to the invention, the sealable substance consists of monomers or polymers having sealing properties, in particular polypropylene (PP), polyethylene (PE), polyester (PET), polyamide, polystyrene (PS), acrylates or a mixture thereof, ethyl vinyl acetate (EVA), biopolymers, or wax-based substances. The type of sealable substance can be varied depending on the requirements of the packaging material. The sealable material can be a cold- or heat-sealable material. The cold-seal material can comprise mixtures containing acrylates and / or adhesives. The heat-sealable material can comprise, for example, a heat-sealing lacquer or a hot-melt adhesive.

[0014] A second aspect of the invention relates to a packaging material comprising a cellulose-containing substrate having a first surface and a second surface opposite the first surface, at least one sealable substance applied in a patterned manner to at least part of a surface area of ​​the first surface of the substrate by means of a printing process, leaving areas not covered with the sealable substance, and at least one barrier layer applied to at least part of a surface area of ​​the second surface of the substrate by means of a printing process. By using printing processes for coating both the first and the second surface of the cellulose-containing substrate, the packaging material according to the invention can be produced cost-effectively at high speed.Time-consuming intermediate steps, such as applying a polymer film by lamination, are no longer necessary. Furthermore, the patterned application of the sealable substance, while leaving areas on the first surface not covered with the sealable substance, ensures that the fibers of the cellulosic substrate can be effectively rehydrated during a recycling process for the packaging material. This results in a high percentage (> 95%) of recyclability of the packaging material according to the invention in conventional deinking processes. The cellulosic substrate can be coated or uncoated paper, coated or uncoated board, or coated or uncoated cardboard or corrugated board. The basis weight / grammage of the cellulosic substrate is between 15 g / m². 2 and 450 g / m 2 . Below values ​​between 15 g / m 2 and 450 g / m 2werden insbesondere Grammaturen von 15, g / m 2 , 20 g / m 2 , 30 g / m 2 , 40 g / m 2 , 50 g / m 2 , 60 g / m 2 , 70 g / m 2 , 80 g / m 2 , 90 g / m 2 , 100 g / m 2 , 110 g / m 2 , 120 g / m 2 , 130 g / m 2 , 140 g / m 2 , 150 g / m 2 , 160 g / m 2 , 170 g / m 2 , 180 g / m 2 , 190 g / m 2 , 200 g / m 2 , 210 g / m 2 , 220 g / m 2 , 230 g / m 2 , 240 g / m 2 , 250 g / m 2 , 260 g / m 2 , 270 g / m 2 , 280 g / m 2 , 290 g / m 2 , 300 g / m 2 , 310 g / m 2 , 320 g / m 2 , 330 g / m 2 , 340 g / m 2 , 350 g / m 2 , 360 g / m 2 , 370 g / m 2 , 380 g / m 2 , 390 g / m 2 , 400 g / m 2 , 410 g / m 2 , 420 g / m 2 , 430 g / m 2 , 440 g / m 2, 450 g / m 2 and corresponding intermediate values. Furthermore, the cellulose-containing substrate can contain at least 10% by weight of recycled cellulose fibers based on the total weight of the substrate. The use of recycled fibers advantageously reduces the consumption of virgin cellulose fibers and thus increases the sustainability of the packaging material produced in this way.

[0015] In further advantageous embodiments of the method according to the invention, the first surface is a surface of the substrate facing away from the product to be packaged with the packaging material. However, it is also possible for the first surface to be a surface of the substrate facing the product to be packaged with the packaging material. This means that the first surface can form an outer or inner surface of the substrate. The inner surface is facing or closer to the product to be packaged or the already packaged product.

[0016] Furthermore, it is possible for approximately 20-90% of the area of ​​the first surface of the substrate to be covered with the sealable substance. Coverage between 20% and 90% refers in particular to values ​​of 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and corresponding intermediate values. Surprisingly, it has been found that this is sufficient to ensure secure sealing of the packaging material or the goods packaged therein. Since the surface is not completely sealed, the recyclability of the packaging material produced in this way is not impaired. This particularly applies to the possibility of rewetting the fibers of the cellulosic substrate.

[0017] Further features and their advantages can be found in the descriptions of the first aspect of the invention, whereby advantageous embodiments of the first aspect of the invention are to be regarded as advantageous embodiments of the second aspect of the invention, and vice versa. The packaging material according to the invention is produced, in particular, by a method according to the first aspect of the invention.

[0018] A third aspect of the invention relates to packaging comprising at least one packaging material that is obtainable and / or obtained by a method according to the first aspect of the invention and / or formed according to the second aspect of the invention. This ensures improved recyclability of the packaging material or the packaging. The packaging can be designed, for example, as food packaging, in particular as packaging for solid foods, as packaging for sweets or as beverage packaging for liquid foods, as packaging for tobacco products, as gift or outer packaging, as carrier packaging, etc.

[0019] Further features and their advantages can be found in the descriptions of the first and second aspects of the invention, wherein advantageous embodiments of the first and second aspects of the invention are to be regarded as advantageous embodiments of the third aspect of the invention and vice versa.

[0020] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combination specified, but also in other combinations without departing from the scope of the invention. Thus, embodiments are also to be considered encompassed and disclosed by the invention that are not explicitly shown and explained in the figures, but which emerge and can be generated through separate combinations of features from the explained embodiments. Embodiments and combinations of features are also to be considered disclosed that therefore do not have all the features of an originally formulated independent claim.

[0021] Figure 1 is a schematic sectional view of the packaging material according to the invention according to one embodiment; and

[0022] Figures 2 to 5 show schematically illustrated top views of packaging materials according to the invention in various further embodiments. Figure 1 shows a schematic side sectional view of a packaging material 10 according to a first exemplary embodiment. The packaging material 10 comprises a cellulose-containing substrate 12, which has a first surface 14 facing away from a packaged item (not shown) and a second surface 16 facing the packaged item. In the illustrated exemplary embodiment, the first surface 14 is an outer side of the substrate 12, and the second surface 16 is an inner side of the substrate 12. In the present exemplary embodiment, the substrate 12 is uncoated paper with a basis weight of approximately 100 g / m 2A sealable substance 18 is applied to the outer side or first surface 14 of the substrate 12 by means of a printing process, wherein the sealable substance 18 is applied in a patterned manner, leaving areas 20 not covered with the sealable substance 18 (see also Figs. 2 to 5). A barrier layer 22 is also applied to the second surface 16 or inner side of the substrate 12 by means of a printing process. In the illustrated embodiment, both the sealable substance 18 and the barrier layer 22 were applied by means of a screen printing process. The barrier layer 22 can be water- and / or moisture- and / or vapor- and / or grease- and / or oil- and / or gas-repellent. In addition, the barrier layer 22 can provide aroma protection for the packaged product, in particular a food product.

[0023] The sealable substance 18 on the first surface 14 enables sealing of the packaging material 10 or the packaging produced with the packaging material 10. In the illustrated embodiment, the sealable substance 18 is a cold-sealable material.

[0024] Figures 2 to 5 show schematic top views of packaging materials 10 according to further embodiments. The embodiments differ in particular in the different, patterned application of the sealable substance 18 to the first surface 14 of the substrate 12. It can be seen that the sealable substance 18 is applied in a wide variety of patterns, shapes, and densities. The type of pattern as well as the distribution on the first surface 14 is determined by the requirements of the packaging material 10. Figure 3, for example, shows three different application patterns of the sealable substance 18, the density distribution of which on the first surface 14 also ranges between 1% and almost 95%. Advantageously, approximately 20-90% of the area of ​​the first surface 14 is covered with the sealable substance 18.The type of pattern is diverse and can consist of single or multiple lines, dots, circles, polygons, diamonds, honeycombs, grids or combinations thereof.

[0025] The parameter values ​​specified in the documents for defining process and measurement conditions for characterizing specific properties of the subject matter of the invention are to be considered as being included within the scope of the invention, even in the event of deviations - for example due to measurement errors, system errors, weighing errors, DIN tolerances and the like.

Claims

Patent claims 1 . A method for producing a coated packaging material (10), in particular a laminate, comprising at least the steps: Providing a cellulosic substrate (12) having a first surface (14) and a second surface (16) opposite the first surface (14); Coating at least part of a surface area of ​​the first surface (14) of the substrate (12) with at least one sealable substance (18) by means of a printing process, wherein the sealable substance (18) is applied in a patterned manner while leaving areas (20) not covered with the sealable substance (18); and Coating at least a part of a surface region of the second surface (16) of the substrate (12) with at least one barrier layer (22) by means of a printing process.

2. Method according to claim 1, characterized in that the first surface (14) is a surface of the substrate (12) facing away from a product to be packaged with the packaging material (10) or that the first surface (14) is a surface of the substrate (12) facing towards a product to be packaged with the packaging material (10).

3. Method according to claim 1 or 2, characterized in that when coating the first surface (14) approximately 20 - 90% of the area of ​​the first surface (14) is covered with the sealable substance (18).

4. Method according to one of the preceding claims, characterized in that the coating of the second surface (16) with the barrier layer (22) takes place over the entire area or part of the area.

5. Method according to one of the preceding claims, characterized in that the barrier layer (22) is sealable.

6. Method according to one of the preceding claims, characterized in that when coating the first surface (14) at least two different sealable substances (18) are applied in different surface areas and / or that when coating the second surface (16) at least two different barrier layers (22) are applied in different surface areas and / or one above the other.

7. Method according to claim 6, characterized in that at least the outer, near-surface barrier layer of the at least two different barrier layers (22) is sealable.

8. Method according to one of the preceding claims, characterized in that for coating the first and second surfaces (14, 16) a printing method from the group consisting of flexographic printing, planographic printing, gravure printing, digital printing, screen printing, embossed printing and / or offset printing and / or an application method from the group consisting of roller application, pour-on application, slit nozzle application and / or curtain coating is used.

9. Method according to one of the preceding claims, characterized in that the viscosity of the sealable substance (18) and the barrier layer (22) is adapted to the type of printing process used, at least during the respective coating process.

10. Method according to one of the preceding claims, characterized in that the barrier layer (22) is designed to be water- and / or moisture- and / or vapor- and / or grease- and / or oil- and / or gas-repellent.

11. Method according to one of the preceding claims, characterized in that the sealable substance (18) consists of monomers or polymers having sealing properties, in particular polypropylene (PP), polyethylene (PE), polyester (PET), polyamide, polystyrene (PS), acrylates or a mixture thereof, of ethyl vinyl acetate (EVA), biopolymers or wax-based substances.

12. Method according to one of the preceding claims, characterized in that the cellulose-containing substrate (12) is paper, cardboard or corrugated cardboard.

13. Method according to one of the preceding claims, characterized in that the cellulose-containing substrate (12) has a grammage of between 15 g / m 2 and 450 g / m 2 has.

14. Method according to one of the preceding claims, characterized in that the cellulose-containing substrate (12) has a proportion of recycled cellulose fibers of at least 10 wt.% based on the total weight of the substrate (12).

15. Packaging material (10) comprising a cellulose-containing substrate (12) having a first surface (14) and a second surface (16) opposite the first surface (14), at least one sealable substance (18) which is applied in a pattern-like manner to at least part of a surface region of the first surface (14) of the substrate (12) by means of a printing process, leaving areas (20) not covered with the sealable substance (18), and at least one barrier layer (22) which is applied to at least part of a surface region of the second surface (16) of the substrate (12) by means of a printing process.

16. Packaging material according to claim 15, characterized in that the first surface (14) is a surface of the substrate (12) facing away from a product to be packaged with the packaging material (10) or that the first surface (14) is a surface of the substrate (12) facing towards a product to be packaged with the packaging material (10).

17. Packaging material (10) according to claim 15 or 16 and manufactured according to one of claims 1 to 14.

18. Packaging which at least partially comprises a packaging material (10) which is obtainable and / or obtained by a method according to one of claims 1 to 14.

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