Roll assembly for producing non-destructive embossed barrier paper for air-tight and water-vapor-tight sealing of packages and corresponding method

Abstract

The present invention relates to a roll assembly for producing a non-destructive embossed barrier paper for air-tight and water-vapor-tight sealing of cigarette packages, in particular for use as an inner liner, the roll assembly having a first embossing roll and a second embossing roll, a nip being formed between the first embossing roll and the second embossing roll for feeding and embossing the barrier paper, at least one of the embossing rolls having a plurality of embossing elements, the embossing elements having, on their upper surface, edges surrounding the embossing elements and having an edge radius of 1 μm to 1000 μm. The present invention also relates to a method for producing a non-destructive embossed barrier paper for air-tight and water-vapor-tight sealing of cigarette packages, in particular for use as an inner liner.

Description

[Technical field]

[0001] The present invention relates to a roll assembly for producing a non-destructive embossed barrier paper for air-tight and water vapor-tight sealing of the package, particularly for use as an inner liner for cigarette packages, the roll assembly having a first embossing roll and a second embossing roll, a nip being formed between the first embossing roll and the second embossing roll to feed and emboss the barrier paper, at least one of the embossing rolls having a plurality of embossing elements.

[0002] For example, a cigarette package usually includes the following components: A cardboard package designed with a corresponding brand layout serves as a container for holding a number of cigarettes; The cigarettes are directly wrapped in an inner liner, which is located together with the cigarettes in the cardboard package; This inner liner is used in particular for simultaneous bulk-filling of carton packages with a number of cigarettes; The cardboard package is covered on the outside by a transparent plastic film, which serves to preserve the taste and freshness of the tobacco product. In the wake of growing environmental awareness and the growing demand for plastic-free product packaging, there is also a need in the tobacco industry for cigarette packages that contain as little plastic as possible. One solution is to transfer the function of the plastic film to the cardboard package or to the inner liner, so as to completely eliminate the plastic film. For this purpose, the cardboard package and / or the inner liner can be composed of a barrier paper, which shields the cigarettes wrapped therein against external environmental influences. At the same time, as legislation becomes more and more stringent, manufacturers are required to print warning and impact images on an ever-increasing scale on cigarette and tobacco packages. This focuses on alternative surfaces on cigarette packages where brand-specific text and / or symbols can be applied. However, embossing methods known from the prior art destroy the fibers and barrier layers to achieve the required element height for the material to be embossed. Thus, there is a need for an embossing process to emboss barrier paper, especially for its use in tobacco packages.

[0003] It is therefore an object of the present invention to provide a roll assembly which allows the introduction of embossing into barrier paper without destroying the barrier function of the barrier paper.

[0004] The object is achieved by means of the features of the independent claims.

[0005] It is therefore provided that the embossing elements each have edges that run around the embossing element at their upper surface with an edge radius between 1 μm and 1000 μm. Preferably, the edges may have an edge radius of more than 10 μm. Particularly preferably, the edges may have an edge radius of more than 100 μm. By providing an edge radius that is not too small, destruction of the barrier layer of the barrier paper can be effectively prevented. The embossing elements can all have the same height or depth. Furthermore, the embossing elements can have a flat surface within the peripheral edge. The barrier paper can necessarily have two layers, the two layers being a paper layer or base paper composed of paper fibers and a lacquer layer or sealing coating that serves to create the barrier properties. In addition, the barrier paper can have a printing coating, which gives the barrier paper particularly good printing properties. The barrier properties can be designed to be aroma barrier, fat barrier, MOSH / MOAH barrier, oxygen barrier, UV barrier and / or water barrier. Furthermore, the barrier paper or especially the barrier layer may be heat-sealable. The diameter of the embossing roll may be up to 2 m. The width of the embossing roll may be up to 6 m. The upper surface of the embossing projection may be provided by a surface facing substantially away from the roll surface. In the case of stepped embossing projections, each surface of each step of the embossing projection within the meaning of the present application may have a separate edge surrounding the respective surface. The peripheral edges may also have different radii along their length, provided that they are larger than the minimum radius required for non-destructive embossing. The upper surface of the recess may be realised by a peripheral edge, which is necessarily at the level of the roll surface and runs around the recess. In the case of stepped recesses, each peripheral edge of each step of the recess within the meaning of the present application may have a separate edge surrounding the respective recess step. The peripheral edges may also have different radii along their length, provided that they are larger than the minimum radius required for non-destructive embossing.It may further be provided that the edges surrounding the embossed protrusions at the level of the roll surface or the edges surrounding the recesses at the level of the recess base have a radius of 1 μm to 1000 μm.For example, the inner package may be an inner liner for a cigarette package.

[0006] It may be provided that at least one embossing roll having a plurality of embossing elements is designed as a male type, the embossing elements extending away from the roll surface as embossing protrusions. It may further be provided that at least one embossing roll having a plurality of embossing elements is designed as a female type, the embossing elements extending as recesses into the roll surface.

[0007] The embossing elements can all have the same height or depth. The embossing elements can instead have a stepped profile, where each step has a peripheral edge with an edge radius of 1 μm to more than 1000 μm. The embossing elements can also have any free shape, provided that they do not exceed a certain embossing height and none of the edge radii are smaller than 1 μm to 1000 μm. This can apply to embossed protrusions and equally to recesses.

[0008] It may also be provided that the back roll of the embossing roll having a plurality of embossing elements has a smooth roll surface having no embossing elements, the roll surface of the back roll being made of steel or an elastic material such as rubber or plastic.

[0009] It may further be provided that the back roll of the embossing roll having a plurality of embossing protrusions is designed as a female mold, the back roll having a plurality of recesses made in the roll surface, the recesses being arranged complementary to the embossing protrusions extending away from the roll surface. The recesses may in particular be designed complementary to the embossing protrusions, so that the embossing protrusions can be precisely engaged in the respective recesses.

[0010] It may further be provided that the back roll of the embossing roll having a plurality of embossing protrusions is designed as a male type, the back roll having a plurality of embossing protrusions extending away from the roll surface, the plurality of embossing protrusions being arranged complementary to the recesses extending into the roll surface. The embossing protrusions may in particular be designed complementary to the embossing protrusions, so that they can precisely engage in the respective recesses.

[0011] It may be provided that the embossing height and / or embossing depth of the embossing elements is at most 200 μm. It may be provided that the embossing height and / or embossing depth of the embossing elements is at most 150 μm. It may be provided that the embossing height and / or embossing depth of the embossing elements is at most 100 μm. The embossing elements may have a flat upper surface. The embossing elements may also have a structured surface with a highest protrusion or deepest recess of at most 200 μm. The embossing elements may in particular have lateral surfaces that extend vertically away from the roll surface. In the case of recesses, they may also have side walls that extend vertically into the roll surface. The side walls of the recesses and / or the side walls of the embossing protrusions may further be angled such that the side walls of the embossing protrusions have an angle of more than 90° to the roll surface and the side walls of the recesses have an angle of less than 90° to the roll surface. It may also be provided that the embossing elements are attached.

[0012] In addition, the first embossing roll and / or the second embossing roll may have an average roughness Rz of 1 to 50 μm.

[0013] It may be provided that each of the embossing elements has a length of more than 0.1 mm in the axial direction of the embossing roll. It may also be provided that each of the embossing elements has a width of more than 0.1 mm in the circumferential direction of the embossing roll. It may also be provided that each of the embossing elements has a length of more than 0.2 mm in the axial direction of the embossing roll. It may also be provided that each of the embossing elements has a width of more than 0.2 mm in the circumferential direction of the embossing roll. Particularly preferably, it may be provided that each of the embossing elements has a length of more than 0.3 mm in the axial direction of the embossing roll. It may also be provided that each of the embossing elements has a width of more than 0.3 mm in the circumferential direction of the embossing roll. The embossing elements may be circular, rectangular, oval, etc., or may have a more complex shape, such as a letter, symbol, or trademark. By providing embossing elements with a minimum size, the surface pressure applied to the material to be embossed can be adjusted and preconfigured to a material-dependent maximum value.

[0014] The invention further relates to a method for producing a non-destructive embossed barrier paper for air-tight and water-vapor-tight sealing of packages, in particular for use as inner packaging, with a roll assembly as claimed in any one of claims 1 to 10, the method comprising the steps of feeding a barrier web to a nip of the roll assembly and forming an embossed pattern in the barrier paper as the barrier web is fed through the nip.

[0015] The method may provide that the barrier paper has a fibre thickness of at most 100 μm. Further, it may be provided that the barrier paper has a fibre length of at most 3 mm.

[0016] The barrier paper may have a paper thickness of 20 μm to 500 μm. Further, the barrier paper may be provided to have a weight of 10 GSM to 800 GSM.

[0017] In particular, it may be provided that the embossed pattern has an embossing height of at most 50 μm. In addition to providing a minimum radius at the embossed edge and realizing a minimum size of the embossing elements, providing a maximum embossing height may be an effective measure to avoid damaging the barrier function of the barrier paper. Furthermore, it may be provided that the roll adjustment is provided to strictly correspond to the paper thickness of the barrier paper used, so that in the areas of the embossing roll that do not have embossing elements, no compression of the paper web takes place, but the barrier paper is merely deformed or compressed in the areas of the embossing elements. In the event that the desired embossed pattern will have a particularly long embossing height, it may be provided that a barrier paper with a thicker barrier or varnish layer is used. It may thus be provided that the thickness of the barrier layer and thus the roll adjustment can be set to the desired embossing height of the embossing pattern.

[0018] It can also be provided that the barrier paper is guided through the nip so that the barrier layer faces away from the embossing projections and towards a back roll designed as a smooth roll or as a female roll.

[0019] Exemplary embodiments of the present invention are described with reference to the following drawings. [Brief description of the drawings]

[0020] [Figure 1] 1 illustrates a top plan view of an embodiment of a roll assembly in accordance with the present invention. [Diagram 2] 1 shows a detailed view of the recesses in the embossing roll designed as a female mold. [Diagram 3] FIG. 2 shows a detailed view of the embossing protrusions in the embossing roll designed as a male mold. [Figure 4] FIG. 2 shows a side view of the embossed barrier paper. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The plan view of an embodiment of a roll assembly 1 according to the invention shown in Figure 1 has a first embossing roll 3 shown at the top of the figure and a second embossing roll 4 shown at the bottom of the figure. In the embodiment shown, the first embossing roll 3 has a plurality of embossing elements in the form of embossing protrusions 7, which have different shapes and sizes and on their top surface each have a minimum radius R of between 1 μm and 1000 μm. K In a corresponding manner, the second embossing roll 4 in the embodiment shown has a plurality of embossing elements in the form of depressions 9, which are also complementary to the embossing protrusions 7 of the first embossing roll 3, but have a different shape and size. The embossing elements shown each have a width B in the circumferential direction Y of at least 0.1 mm. P and a length L in the axial direction X of at least 0.1 mm P Each of the recesses 9 also has a minimum radius R of 1 μm to 1000 μm on the plane of the roll surface 8. K Both embossing rolls 3, 4 have a peripheral edge 6 having a surface roughness R of 1 to 50 μm. Z Both rolls 3, 4 are arranged in an axial direction X relative to each other such that they form a nip 5 between them. This means that, by adjustable roll adjustment, both embossing rolls 3, 4 are arranged parallel to each other and aligned relative to each other such that the embossing protrusions 7 can engage in corresponding complementary recesses 9 when the barrier paper 2 is fed through the nip 5. Both embossing rolls 3, 4 are driven in opposite rotational directions Y.

[0022] FIG. 2 illustrates a detailed view of the recesses 9 in the embossing roll 4 designed as a female mold, as shown in FIG. 1. The recesses 9 shown have an embossing depth T of up to 200 μm in the radial direction Z of the embossing roll 4. P and a length L of at least 0.1 mm in the axial direction X P The side walls of the recesses are perpendicular to the roll surface 8.K It can be seen that the edge 6 surrounding the recess 9 in the plane of the roll surface 8 having a radius of 0.1 mm provides a relatively smooth transition between the sidewall of the recess 9 and the roll surface 8. In contrast, the edge at the base of the recess has a sharper radius.

[0023] FIG. 3 shows a detailed view of the embossing projections 7 of the embossing roll 3 designed as a male from FIG. 1. The embossing projections 7 shown have an embossing height H of up to 200 μm in the radial direction Z of the embossing roll 3. P and a length L of at least 0.1 mm in the axial direction X P , and the sides of the embossing protrusions 7 are aligned perpendicular to the roll surface 8 as in the recesses 9 in FIG. 2. The embossing protrusions 7 have a flat upper surface. A minimum radius R of 1 μm to 1000 μm K It can be seen that the edge 6 surrounding the embossing protrusion 7 at its upper surface 7 having a radius of 0.1 mm provides a relatively smooth transition between the side of the embossing protrusion 7 and the upper surface of the embossing protrusion 7. In contrast, the edge surrounding the embossing protrusion 7 in the plane of the roll surface 8 has a sharper radius on the underside of the embossing protrusion 7.

[0024] Figure 4 shows a side view of a barrier paper 2 that has been embossed by the method according to the invention. It comprises a paper layer 11 and an overlying barrier layer 12. The paper layer 11 comprises a plurality of paper fibres 13, the plurality of paper fibres 13 having a fibre length L of up to 3mm. F and a fiber thickness D of up to 100 μm F The combined thickness or paper thickness S of the barrier paper 2 composed of the paper layer 11 and the barrier layer 12 P is between 20 μm and 500 μm. On the top surface of the barrier paper 2, i.e. on the side of the barrier layer 12, the barrier paper 2 has an embossed pattern 10, which is formed from a plurality of individual elements spaced apart from each other in the axial direction X, as shown. The height H of the embossed pattern PM is a maximum of 50 μm.

[0025] The features of the invention disclosed in the above description, in the drawings and in the claims can be essential for the implementation of the invention both individually and in any combination. [Explanation of symbols]

[0026] 1 Roll Assembly 2. Barrier Paper 3 First embossing roll 4 Second embossing roll 5 Nip 6. Edge 7 Embossed convex part 8 Roll Surface 9 Recess 10 Embossed Patterns 11 paper layer 12 Barrier layer 13 Paper Fibers X-axis direction Y circumferential direction Z radial direction H P Embossing Height H PM Embossed pattern height T P Embossing Depth L P Length of embossing element B P Embossing element width D F Fiber Thickness L F Fiber Length R K Edge Radius R z Average roughness S P Paper Thickness

Claims

1. 1. A roll assembly for producing a non-destructive embossed barrier paper for airtight and water vapor tight sealing of packages, in particular for use as an inner package, comprising: a first embossing roll; a second embossing roll; a nip is formed between the first embossing roll and the second embossing roll through which the barrier paper is fed and embossed; at least one of the embossing rolls has a plurality of embossing elements; The embossing elements have an edge radius (R Ｋ ) having an edge surrounding the embossing element; The roll assembly.

2. 2. The roll assembly of claim 1, wherein at least one of the embossing rolls having the plurality of embossing elements is designed as a male roll, the embossing elements extending away from the surface of the roll as embossing protrusions.

3. 10. The roll assembly of claim 1, wherein at least one of the embossing rolls having the plurality of embossing elements is designed as a female roll, the embossing elements extending as recesses into the surface of the roll.

4. 2. The roll assembly of claim 1, wherein the backing roll of the embossing roll having the plurality of embossing elements has a smooth roll surface without embossing elements, and the roll surface of the backing roll is made of an elastic material such as steel or rubber.

5. 3. The roll assembly of claim 2, wherein the backing roll of the embossing roll having the plurality of embossing protrusions is designed as a female mold, and the backing roll has a plurality of recesses formed in the roll surface of the backing roll, the recesses being positioned complementary to the embossing protrusions extending away from the roll surface of the embossing roll.

6. 4. The roll assembly of claim 3, wherein the backing roll of the embossing roll having the plurality of recesses is designed as a male type, and the backing roll has a plurality of embossing protrusions extending away from the roll surface of the backing roll, the protrusions being positioned complementary to the recesses extending into the roll surface of the embossing roll.

7. The embossing height (H Ｐ ) and / or embossing depth (T Ｐ 2. The roll assembly of claim 1, wherein the thickness of the first and second electrodes is at most 200 μm.

8. The first embossing roll and / or the second embossing roll have an average surface roughness (R ｚ 10. The roll assembly of claim 1, wherein

9. The embossing elements in the axial direction (X) of the embossing roll each have a length (L Ｐ 10. The roll assembly of claim 1, wherein

10. The embossing elements in the circumferential direction (Y) of the embossing roll each have a width (B Ｐ 10. The roll assembly of claim 1, wherein

11. 11. A method for producing a non-destructive embossed barrier paper for airtight and water vapor tight sealing of cigarette packages, in particular for use as an inner liner, with a roll assembly according to any one of claims 1 to 10, comprising: feeding a barrier web through the nip of the roll assembly; forming an embossed pattern in the barrier web as it is fed through the nip; The method comprising:

12. The barrier paper has a fiber thickness (D Ｆ 12. The method of claim 11 , wherein

13. The barrier paper has a fiber length (L Ｆ 12. The method of claim 11 , wherein

14. The thickness of the barrier paper (S Ｐ 12. The method of claim 11, wherein the thickness of the first electrode is 20 μm to 500 μm.

15. The embossed pattern has an embossing height (H) of up to 50 μm. ＰＭ 12. The method of claim 11 , wherein

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