Method and coating layer application device for applying a coating layer to a packaging material - Patents.com

Abstract

1. A method for applying a coating layer to a cellulose packaging material, the method comprising: providing a cellulose layer having a first side and a second side; providing a moving endless surface having a grid zone having a plurality of recesses; loading a predetermined amount of coating layer material into the plurality of recesses of the grid zone; retaining a predetermined amount of coating layer material in the plurality of recesses; contacting the grid zone with the first side of the cellulose layer; applying the predetermined amount of coating layer material from the plurality of recesses to the first side of the cellulose layer; and forming a coating layer on the first side of the cellulose layer using the predetermined amount of coating layer material.

Description

[Technical field]

[0001] The present invention relates to a method for applying a coating layer to a cellulosic packaging material in order to set the moisture vapor transmission rate of the packaging material. The present invention further relates to a grid roller for use in the method. The present invention also relates to an apparatus for applying a coating layer for setting the moisture vapor transmission rate of a cellulosic packaging material. [Background technology]

[0002] A first known technique for applying a coating layer to a cellulose packaging material consists of spraying a coating layer material onto the cellulose packaging material. Herein, a spray installation is used that comprises one or more spray nozzles directed towards the cellulose packaging material. The spray installation conveys the coating layer material to the spray nozzle under pressure. The spray nozzle then sprays the coating layer material onto the cellulose packaging material to form a coating layer. In other words, the spray nozzle sprays the coating layer material onto the cellulose packaging material. The spraying of the coating layer material requires that the coating layer material has a low viscosity, which means that the coating layer material must be flowable. The coating layer material must have a viscosity that corresponds, for example, to the viscosity of water under normal conditions. Such coating layer materials are expensive and difficult to manufacture. Such spray installations are more complex, require more maintenance and have a relatively limited productivity compared to the subsequent second technique. This second known technique involves the use of a rotary printing machine with a rotatable cylinder. The cylinder is partially immersed in a container containing the coating layer material. The cylinder then rotates about its axis, whereby it takes up the coating layer material from the container in a continuous manner. The pressing cylinder is then used to press the cellulose packaging material against the rotatable cylinder, whereby the coating layer material is applied to the cellulose packaging material. The productivity of this second technique is considerably higher than the first technique, since the cellulose packaging material is conveyed along the rotatable cylinder at a higher speed. However, the amount of coating layer material applied can hardly be set. Moreover, such rotary presses can only be controlled to a limited extent. Reducing the pressure of the pressing cylinder against the paper therefore leads to irregularities in the coating layer on the final cellulose packaging material. A further disadvantage of rotary presses is the impossibility of applying a specific amount of coating layer material in a predetermined manner. Summary of the Invention

[0003] An object of the present invention is to provide a method for applying a coating layer to a cellulosic packaging material in order to set the moisture permeability of the packaging material with improved control. A second object of the present invention is to provide an apparatus for applying a coating layer with improved control.

[0004] According to a first aspect, the invention relates to this purpose a method for applying a coating layer to a cellulosic packaging material with the aim of setting the moisture vapor transmission rate of the packaging material, comprising: providing a cellulose layer having a first surface and a second surface; providing a moving endless surface including a grid zone having a plurality of recesses; - incorporating a quantity of coating layer material into a plurality of recesses in a grid zone; - retaining a quantity of coating layer material in a plurality of recesses; - contacting the grid zone with a first side of the cellulose layer; - applying a quantity of coating layer material to a first surface of the cellulose layer from a plurality of recesses; - forming a coating layer on the first surface of the cellulose layer with a predetermined amount of coating layer material.

[0005] The recesses of the grid zone take up a predefined amount of coating layer material, for example by capillary action in the recesses, then retain this amount of coating layer material and apply it to the cellulose layer, so that the amount of coating layer material applied to the cellulose layer is always known. Furthermore, the amount of coating layer material can be predetermined. This is possible by changing the size of the recesses of the grid zone. This therefore also means that the amount of coating layer material can always be pre-changed and thus controlled. Furthermore, the moisture permeability of the packaging material can also be controlled in an optimal manner hereby.

[0006] The grid zone preferably comprises a first grid zone portion and a second grid zone portion, the first grid zone portion and the second grid zone portion each comprising a plurality of first recesses and a plurality of second recesses, the plurality of first recesses and the plurality of second recesses respectively capturing, retaining and applying a first predetermined amount of coating layer material and a second predetermined amount of coating layer material, the first predetermined amount of coating layer material being different from the second predetermined amount of coating layer material. Cellulose packaging materials are used in all kinds of forms and applications. After forming a coating layer on the cellulose packaging material, these packaging materials are typically formed according to the application of the cellulose packaging material. Thus, a bread bag can be formed, for example, by folding the cellulose packaging material and then gluing it to the corresponding side. However, the coating layer interferes with the adhesiveness of the cellulose packaging material, thereby causing the mutually bonded cellulose packaging materials to loosen. This has a negative effect on the quality of the final assembled packaging material. A grid zone having a first and a second grid zone portion, each of which takes up, retains and applies a respective amount of coating layer material, has the advantage that the amount of coating layer material in each grid zone portion is controllable, for example according to the intended purpose of the packaging material. This allows the amount of coating layer material applied to be controlled locally according to the intended purpose of the cellulosic packaging material. Thus, for example, significantly more coating layer material can be taken up, retained and applied in the first grid zone portion than in the second grid zone portion, and vice versa. According to the above example, the coating layer adheres better where less coating layer material is locally applied. Based on the above, it will be clear that according to the preferred embodiment, the controllability is further improved.

[0007] The moving endless surface is preferably further provided with a blank zone on the first side of the cellulose layer where no coating layer material is applied, thereby allowing the creation of a zone on the cellulose packaging material where adhesion is optimal.

[0008] The dimensions of the plurality of recesses are preferably such that the coating layer has a thickness of 10 to 12 g / m 2 More preferably, it is in the range of 8 to 10 g / m 2 Most preferably, in the range of 1 to 8 g / m 2 The dimensions are such that the coating layer has a weight in the range of 1 to 5 g / m. Research by the present inventors has shown that the moisture permeability of the coating layer is S-shaped proportional to the amount of coating layer material applied. 2 A coating layer having a weight of 10-12 g / m2 has acceptable moisture permeability and optimal adhesion properties. It will be apparent that the amount of coating layer will also depend on the type of cellulose layer, as further described below. Such a coating layer is also less expensive compared to coating layers in which more coating layer material is applied. The inventors have found that a coating layer having a weight of 10-12 g / m2 has acceptable moisture permeability and optimal adhesion properties. 2 It has further been found that a coating layer having a weight of 10 to 12 g / m approaches the minimum moisture permeability in an asymptotic manner. Thus, the optimum moisture permeability is between 10 and 12 g / m 2 The optimum moisture permeability is achieved when a coating layer having a weight of 12 g / m is applied. 2 It is understood to mean that application of a coating layer having a weight exceeding this will have little positive effect on the moisture vapor transmission rate.

[0009] Contacting the grid zone with the first side of the cellulose layer preferably includes pressing the first side of the cellulose layer against the grid zone of the moving endless surface, which improves the transfer of coating layer material from the grid zone to the cellulose layer, and thus the coating layer is applied in an improved manner.

[0010] The pressing is preferably carried out by means of a pressing cylinder, which is considered to be preferable since it allows the coating layer to penetrate even further into the cellulose layer.

[0011] The application of the amount of coating layer material to the first side of the cellulose layer is preferably interrupted. This has a positive effect on the further processing of the cellulose layer. Thus, the cellulose layer is, for example, better foldable or adhesive at the location of the interruption.

[0012] The interruption in application of the coating layer to the first side of the cellulose layer preferably comprises an interruption in contacting a grid zone with the first side of the cellulose layer. The interruption in contacting the grid zone ensures that no coating layer material is applied to the cellulose layer, thereby optimally controlling the quality of the final cellulose layer. The interruption in contacting is further preferably performed using a hopper mechanism movably connecting the press cylinder to a camshaft, the camshaft being configured to translate its rotational movement into an up and down movement of the hopper mechanism, whereby contact between the cellulose layer and the moving endless surface is interrupted.

[0013] The coating layer preferably comprises an oily compound such as paraffin or vegetable oil, for example palm oil or soybean oil or mixtures thereof are preferably used.

[0014] The coating layer is preferably applied in a pattern. The pattern of the coating layer preferably comprises repeating elements. The repeating elements preferably have a zero-dimensional or one-dimensional form, such as dots, lines, circles, etc. The repeating elements can furthermore have other forms, such as zigzag lines, step shapes, sine shapes, rectangles, squares, triangles, etc. It is furthermore preferred that the repeating elements have a fixed width. It is furthermore preferred that the repeating elements are arranged at a uniform mutual distance, thereby resulting in a pattern of lines and intermediate regions. It is furthermore preferred that the vertical distance between the repeating elements is at most four times greater than the width of the repeating elements. It is furthermore preferred that the vertical distance is at most three times or at most two times the width of the repeating elements.

[0015] Loading the quantity of coating layer material into the plurality of recesses of the grid zone preferably includes loading the coating layer material into the recesses in a capillary manner.

[0016] The cellulosic packaging material is preferably a food, such as bread, baked goods, vegetables, fruit, cheese, or meat, or a non-food cellulosic packaging material.

[0017] The moving endless surface is preferably a grid roller.

[0018] The coating layer is 15 to 200 g / m 2 / day, preferably 15 to 180 g / m 2 / day, more preferably 15 to 150 g / m 2 / day, and even more preferably 15 to 120 g / m 2 / day. The moisture permeability is measured according to DIN 53-122-1 at 25°C and 75% relative humidity. The moisture permeability is also known in the art as MVTR (moisture vapour transmission rate). This low moisture permeability is achieved by passing a cellulose layer through a cellulose fiber layer at a moisture permeability of about 15 g / m 2 This makes it an effective alternative to conventional plastics, which have a vapor permeability rate of 100 / day, making it preferable. The further reduction in MVTR appears to be partly related to the fact that the coating layer does not penetrate all the way through the cellulose layer. By penetrating into the cellulose layer, the oil apparently creates hydrophobic pores through which vapor can diffuse and not adhere to the previously hydrophilic cellulose.

[0019] The method preferably further comprises providing a further moving endless surface comprising a grid zone having a plurality of recesses, incorporating a predetermined amount of coating layer material in the plurality of recesses of the grid zone of the further moving endless surface, retaining a predetermined amount of coating layer material in the plurality of recesses of the further moving endless surface, contacting the grid zone with the second side of the cellulose layer, applying the predetermined amount of coating layer material from the plurality of recesses of the further moving endless surface to the second side of the cellulose layer, and forming a further coating layer on the second side of the cellulose layer using the predetermined amount of coating layer material.

[0020] According to a second aspect, the present invention relates to this purpose to a coating layer application device for setting the moisture permeability of a cellulose packaging material, comprising a moving endless surface for applying a coating layer to a cellulose packaging material comprising a cellulose layer having a first side and a second side, the cellulose layer moving in a movement direction through the coating layer application device, the moving endless surface comprising a grid zone having a plurality of recesses, the plurality of recesses being - incorporating a quantity of coating layer material into a plurality of recesses in the grid zone; - configured to hold a quantity of coating layer material in a plurality of recesses; the moving endless surface is positionable adjacent to / in contact with the first side of the cellulose layer, - applying a quantity of coating layer material to the first surface of the cellulose layer from a plurality of recesses; and - further configured to form a coating layer on the first side of the cellulose layer with a predetermined amount of coating layer material.

[0021] Those skilled in the art will appreciate that similar advantages and objectives apply, mutatis mutandis, to the present method and corresponding coating layer application apparatus.

[0022] The grid zone preferably comprises a first grid zone portion and a second grid zone portion, the first grid zone portion and the second grid zone portion each comprising a plurality of first recesses and a plurality of second recesses, the first plurality of recesses and the second plurality of recesses each capturing, retaining and applying a first predetermined amount of coating layer material and a second predetermined amount of coating layer material, respectively, the first predetermined amount of coating layer material being different from the second predetermined amount of coating layer material.

[0023] The coating layer application device is preferably configured to interrupt the application of the coating layer, viewed transversely to the direction of movement of the cellulose layer.

[0024] Preferably, the moving endless surface is further provided with a blank zone on the first side of the cellulose layer where no coating layer material is applied.

[0025] The dimensions of the recesses are preferably such that the coating layer is 10 to 12 g / m 2 More preferably, the range is 8 to 10 g / m 2 and most preferably in the range of 1 to 8 g / m 2 The dimensions are such that the weight is in the range of

[0026] The coating layer application device preferably comprises a pressure cylinder configured to press the cellulose layer against the surface of the moving endless surface to achieve contact between the cellulose layer and the grid zone.

[0027] Preferably herein, the coating layer application device is configured to interrupt contact between the cellulose layer and the grid roller.

[0028] The coating layer application device preferably includes a hopper mechanism movably connecting the pressing cylinder to a camshaft, the camshaft being configured to convert its rotational motion into an up and down motion of the hopper mechanism, thereby interrupting contact between the cellulose layer and the grid roller.

[0029] The coating layer preferably comprises an oily compound such as paraffin or vegetable oil.

[0030] The coating layer is preferably applied in a pattern.

[0031] The plurality of recesses preferably take up the coating layer material in a capillary manner.

[0032] The cellulosic packaging material is preferably a bread packaging material for bread bags.

[0033] The moving endless surface is preferably a grid roller.

[0034] The coating layer is 15 to 200 g / m 2 / day, preferably 15 to 180 g / m 2 / day, more preferably 15 to 150 g / m 2 / day, and even more preferably 15 to 120 g / m 2 It is preferable that the water vapor permeability is 1 / day.

[0035] The coating layer application device preferably comprises a coating layer material compartment containing a volume of coating layer material, the grid roller being partially immersed in the volume of coating layer material.

[0036] The coating layer application device preferably comprises a further moving endless surface including a grid zone having a plurality of recesses configured to take up a predetermined amount of coating layer material in the plurality of recesses of the grid zone of the further moving endless surface and to retain a predetermined amount of coating layer material in the plurality of recesses of the further moving endless surface, the further moving endless surface being positionable adjacent to the second side of the cellulose layer (10) and further configured to apply a predetermined amount of coating layer material from the plurality of recesses to the second side of the cellulose layer (10) and to form a further coating layer on the second side of the cellulose layer (10) using the predetermined amount of coating layer material.

[0037] According to a third aspect, the present invention provides a grid roller for use in the above-mentioned method, and optionally in the above-mentioned apparatus, the grid roller having a surface provided at least in part with grid zones comprising a plurality of recesses configured to take up respective predetermined amounts of coating layer material and then apply the coating layer material to the cellulose layer.

[0038] According to a fourth aspect, the present invention provides a cellulosic packaging material, in which a coating layer for setting the moisture vapor transmission rate of the packaging material is applied according to the method described above, preferably using the apparatus described above.

[0039] According to a fifth aspect, the present invention provides a cellulosic packaging for food products, such as bread, baked goods, vegetables, fruit, cheese, meat, fish, or non-food products, the cellulosic packaging being made from the cellulosic packaging material described above. [Brief description of the drawings]

[0040] The above and other advantageous features and objects of the present invention will become more apparent and the invention will be better understood by reference to the following detailed description when read in conjunction with the accompanying drawings. [Figure 1] FIG. 2 illustrates a perspective view of a moving endless surface having grid zones according to one embodiment. [Diagram 2] FIG. 2 is a perspective view of the moving endless surface and pressure cylinder of FIG. 1; [Diagram 3] FIG. 2 is a schematic diagram of a grid zone having first and second grid zone portions and a cellulose layer with a corresponding coating layer according to an exemplary embodiment. [Figure 4] FIG. 2 illustrates a perspective view of a hopper mechanism, according to one embodiment. [Diagram 5] FIG. 13 is a schematic diagram of a grid zone having first and second grid zone portions and a cellulose layer with a corresponding coating layer according to a further exemplary embodiment. [Figure 6A] FIG. 2 is a schematic diagram of a method for applying a coating layer according to a preferred embodiment. [Figure 6B] FIG. 2 is a cross-sectional side view of a coating layer application apparatus according to a preferred embodiment. [Figure 7] A1, A2, B1, B2 are perspective views of cellulose packaging produced from cellulose packaging material having a coating layer applied according to the method shown in FIG. 6A and / or using the apparatus shown in FIG. 6B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The invention will now be explained further on the basis of exemplary embodiments shown in the drawings.

[0042] The same or similar elements are designated by the same reference numbers in the drawings.

[0043] Figure 1 is a schematic perspective view of a moving endless surface 35 according to a preferred embodiment. The moving endless surface 35 comprises a grid zone 36 having a plurality of recesses 37. Figure 1 further shows that a cellulose layer 10 is provided on the moving endless surface 35, and that a coating layer 20 is applied to the cellulose layer 10.

[0044] The cellulose layer 10 has a first side, visible in Figure 1, and a second side (not shown). The cellulose layer 10 is intended to function as a cellulose packaging material, such as a packaging material for bread, baked goods, vegetables, fruits, cheese, meat, fish, or non-food products. The packaging material is preferably intended to form a cellulose package 100, as shown in Figures 7A1, 7A2, 7B1, and 7B2. In a preferred embodiment, the cellulose layer 10 is substantially formed by a combination of long and short cellulose fibers.

[0045] The cellulose layer 10 is fed to a moving endless surface 35. In the preferred embodiment shown, the moving endless surface 35 is a roller. The roller comprises a grid zone 36 having a plurality of recesses 37. Thus, a grid roller 30 is shown in the figures. However, one skilled in the art will appreciate that a conveyor belt can be constructed in a similar manner instead of or in addition to the grid roller 30.

[0046] The recesses 37 are configured to take up the coating layer material. The recesses 37 are preferably depressions in the moving endless surface. In other words, the recesses are formed by hollowing out the surface. The recesses 37 therefore extend in a direction away from the surface. The recesses have an inlet opening at the location of the surface through which the coating layer material can be taken up, the recesses preferably only having one inlet opening. The recesses can include a bottom located at a distance from the surface, for example 1 mm from the surface. The recesses can also be formed by forming upright walls on the surface, but recesses formed in this way are more difficult to produce than hollowing out the surface and also carry the risk of damaging the cellulose layer to be treated. Hollowing out the recesses can be carried out, for example, with the aid of a laser engraving device. The walls can be arranged in a grid on the surface, for example to form grid zones. The recesses are described further below. The coating layer material preferably comprises an oily compound, such as paraffin or vegetable oil. It is preferred to apply a coating layer based on vegetable components, in particular vegetable oils such as palm oil, sunflower oil, etc. In this way, a cellulose packaging material is obtained that is substantially completely recyclable or otherwise compostable. In this way, furthermore, there is no risk of mineral oil coming into contact with bread or any other foodstuffs in the bag. The vegetable oil preferably comprises a modified vegetable oil having a melting point higher than 40°C, preferably higher than 50°C, even more preferably higher than 55°C or 60°C. An oil with a melting point this high ensures that the coating layer on the cellulose layer is in a solid state at room temperature. It will be clear to the skilled person that the melting point of the modified vegetable oil can be set or selected according to the intended use of the cellulose layer or packaging material thus obtained. Thus, a cellulose layer having a coating layer that comprises a modified oil with a very high melting temperature, for example sunflower oil with a melting point of 70°C, is suitable for example to be produced or stored in an environment where the temperature can be very high, for example at 45°C, an example of which is used as a packaging material for heated snacks.The vegetable oil is preferably selected from the group consisting of palm oil, soybean oil, sunflower oil, olive oil, almond oil, argan oil, avocado oil, borage oil or starflower oil, grape seed oil, hemp seed oil, jatropha oil, cottonseed oil, coconut oil, canola oil, linseed oil, macadamia oil, corn oil, palm kernel oil, peanut oil or groundnut oil, rapeseed oil, rice germ oil or rice bran oil, safflower oil, sesame oil, wheat germ oil, evening primrose oil, walnut oil and castor oil, or mixtures thereof. The vegetable oil is more preferably palm oil or sunflower oil, or a mixture of palm oil and sunflower oil.

[0047] The recess 37 also allows the use of coating layer materials with high viscosity. In comparison to known systems that typically use coating layer materials with low viscosity, for example 1 mPa.s or less, the recess 37 allows the use of coating layer materials with high viscosity. The viscosity of the coating layer material is preferably in the range of 10 to 500 mPa.s. As an example, a comparison can be made between known systems using coating layer materials with a viscosity similar to or less than that of water, and the recess 37 allowing the use of coating layer materials with a viscosity similar to or more than that of honey. The inventors have found that the dangerous situation in which the coating layer material starts to swell during the rotation of the endless surface 35 is reduced to a considerable extent. This is because the swirling creates a dangerous situation in which the coating layer material splashes out of the container. The increase in viscosity opposes the swirling of the coating layer material, thereby making the method and the device for applying the coating layer safer.

[0048] The uptake of the coating layer material into the recesses 37 is preferably performed in a capillary manner. The coating layer material is sucked into the recesses 37 from the coating layer material container by capillary action. In other words, the recesses 37 suck the coating layer material from the coating layer material container into the respective cavities. The uptake of the coating layer material is considered in more detail with reference to FIG. 6. Alternatively or additionally, the coating layer material can be brought to a location in the recesses 37 via a groove in the moving endless surface. Alternatively or additionally, the coating layer material can be poured onto the recesses.

[0049] The recesses 37 are arranged on the surface of the grid roller 30. The recesses 37 can have different shapes and can also differ from each other. Thus, the recesses 37 can have a pyramidal shape, for example a single-sided or tetrahedral (not shown). Alternatively or in combination, the recesses can be spherical, cylindrical or hexahedral recesses (not shown). The dimensions of the recesses 37 determine the amount of coating layer material that is taken up. Thus, the dimensions of the recesses are determined so that the coating layer is 10-12 g / m 2 More preferably, it is in the range of 8 to 10 g / m 2 Most preferably, in the range of 1 to 8 g / m 2 The dimensions of the recesses are preferably selected depending on the coating layer material to be applied. Research by the inventors has shown that the moisture permeability is S-shaped proportional to the amount of coating layer material applied. S-shaped proportional is understood to mean that the moisture permeability of the cellulose packaging material follows an S-shaped progression as a function of the amount of coating layer material applied. More specifically, S-shaped is understood to mean a logistic function. Thus, the moisture permeability is preferably selected depending on the amount of coating layer material applied. 2 A coating layer having a weight of 200 g / m 2 / day. Note that the moisture permeability is highly dependent on the type of cellulose layer and coating layer material. 2The coating layer having a weight of 10-12 g / m further has a relatively good adhesive property against moisture vapor transmission. Such a coating layer is also cheaper compared to a coating layer in which more coating layer material is applied. Furthermore, it is clear that these properties depend on the type of cellulose layer, the amount of coating layer and the type of coating layer, and that they have a mutual effect on each other. The inventor has found that a coating layer having a weight of 10-12 g / m 2 It has further been found that a coating layer having a weight of 10 to 12 g / m approaches the minimum moisture permeability in an asymptotic manner. Thus, the optimum moisture permeability is between 10 and 12 g / m 2 The optimum moisture permeability is achieved when a coating layer having a weight of 12 g / m is applied. 2 It is understood that applying a coating layer having a weight exceeding 1 g / m2 has little positive effect on the moisture permeability and is more expensive. Surprisingly, the present inventors have found that the dimensions of the recesses are 1 to 8 g / m2. 2 It has been found that such packaging materials have the most suitable combination of properties, both commercially and qualitatively, when they correspond to a coating layer having a weight of 1 g / m2. It is further noted that the coating layers can be applied to one or both sides of the paper in the same or different amounts. Thus, 2 of coating layer material can be applied to the first side, for example, at 10 g / m 2 can be applied to the second side. Alternatively, 10 g / m 2 Assuming that the coating layer material is applied as a whole, 5 g / m 2 It is also possible to apply a coating layer material of 10 g / m2 to each side of the cellulose material. 2 It has been shown that it is more efficient to provide a coating layer material of 15 to 200 g / m2 on only one side. 2 / day, preferably 15 to 180 g / m 2 / day, more preferably 15 to 150 g / m 2 / day, and even more preferably 15 to 120 g / m 2 / day, the vapor permeability being measured according to DIN 53-122-1 at 25°C and 75% relative humidity. This low vapor permeability allows the paper bag to have a vapor transmission rate of about 15 g / m 2 This makes it an effective alternative to conventional plastic bread bags, which have a vapor permeability of 10 ...

[0050] The recesses 37 together form a grid zone 36. The recesses 37 are preferably applied in a repeating pattern on the surface 35 of the grid roller 30. The recesses in the grid zone 36 preferably have the same configuration. This allows for a uniform application of the coating layer across the entire dimension of the grid zone. The grid zone is discussed in more detail with reference to FIG. 3.

[0051] The grid roller 30 is movable about the axis of the grid roller 30 when viewed in the longitudinal direction of the grid roller 30. In other words, a moving endless surface is formed by rotating the grid roller 30 about its axis A. Thus, as shown in Figure 6, the grid roller can pick up, hold and apply the coating layer material to the cellulose layer in one revolution about its axis A.

[0052] FIG. 1 further shows that the grid zone 36 is in contact with the first side of the cellulose layer 10. By contacting the cellulose layer 10 with the grid zone 36, a predetermined amount of coating layer material is applied to the first side from the plurality of recesses 37. Thus, the coating layer 20 is formed on the first side of the cellulose layer 10, and the amount of coating layer material used for the coating layer 20 is advantageously known in advance. The coating layer 20 is preferably applied to the more closed side of the paper. It is further noted that the device can also be utilized to apply a coating layer to cardboard. Cardboard is also a cellulose layer that can be fed. Typically, one side of the cardboard is provided with a coating where the cardboard absorbs little or no coating layer material. However, the coating layer material can be applied to the other side of the cardboard in an efficient manner, as described above.

[0053] FIG. 2 is a perspective view of the grid roller 30 of FIG. 1, where a pressing cylinder 50 presses the cellulose layer 10 against the grid zone and / or against the grid roller 30. This is preferred since the applied coating layer 20 thereby penetrates further into the cellulose layer. FIG. 2 further shows that the cellulose layer 10 can be fed to the grid roller 30 in different ways. Thus, the cellulose layer 10 can be fed at an angle to the grid roller 30 or to the pressing cylinder 50. The cellulose layer 10 can be fed, for example, at an angle of 90° or at an angle of 45° to the horizontal plane. The cellulose layer 10 fed at an angle of 90° shares a larger contact surface with the pressing cylinder 50. The cellulose layer 10 is fed from a downstream direction. Then the coating layer is applied and the cellulose layer 10 is discharged at an angle. Herein, the cellulose layer 10 is prevented from sagging on the grid roller 30, whereby the coating layer can be applied in an optimal manner. Furthermore, this also allows the coating layer application device to be constructed more compactly.

[0054] 3 shows a grid roller 30 provided with a grid zone 36 having a first grid zone portion 36a and a second grid zone portion 36b. For illustrative purposes, an unrolled top view of the outer surface of the grid roller 30 is further shown. As well as the unrolled outer surface, the cellulose layer 10 is shown with a coating layer obtained by contacting the cellulose layer 10 with the illustrated grid zone. The coating layer comprises a first coating layer zone 20a and a second coating layer zone 20b similar to the first grid zone portion 36a and the second grid zone portion 36b, respectively.

[0055] The first and second grid zone portions 36a, 36b each comprise a plurality of first recesses and a plurality of second recesses for capturing, retaining and applying a first and a second predetermined amount of coating layer material, respectively. In the illustrated preferred embodiment, the first grid zone portion 36a includes more recesses than the second grid zone portion 36b. This is illustrated based on a square grid shown in the figure, and it will be apparent that there are more squares in the first grid zone portion 36a than in the second grid zone portion 36b. By varying the number of recesses, the amount of coating layer material captured, retained and applied can be controlled.

[0056] Thus, the first grid zone portion 36a takes up a first predetermined amount of coating layer material and then applies it to the cellulose layer, so that the first coating layer zone 20a is formed according to the first predetermined amount of coating layer material. Similarly as before, the second grid zone portion 36b applies a second predetermined amount of coating layer material to the cellulose layer 10, so that the second coating layer zone 20b is formed. The amount of coating layer material applied is indicated based on the amount of lines in the respective coating layer zones 20a, 20b. It will be clear that the first predetermined amount of coating layer material is therefore different from the second predetermined amount of coating layer material.

[0057] The first and second recesses are further configured to take up, retain and apply a first and second predetermined amount of coating layer material, respectively. As mentioned above, the first predetermined amount of coating layer material is different from the second predetermined amount of coating layer material. Another way of controlling the amount of coating layer material taken up, retained and applied is realized by changing the size and / or shape of the recesses. As a result, the predetermined amount of coating layer material for each recess, and therefore for each grid zone portion 36a, 36b, can be adjusted by increasing or decreasing the size of the recesses. It will be clear that both the size of the recesses and the number of recesses have an influence on the amount of coating layer material taken up, retained and applied. On the one hand, it will be clear that the amount of coating layer material applied as a coating layer is always known in advance. On the other hand, it will be clear that the moisture permeability of the final cellulose packaging material can be controlled hereby. In the illustrated embodiment of FIG. 3, the first grid zone portion 36a applies more coating layer material to the cellulose layer 10 than the second grid zone portion 36b. Thus, the coating layer at the position of the first coating layer zone 20a contains more coating layer material than the coating layer at the position of the second coating layer zone 20b. Thus, the coating layer at the position of the first coating layer zone 20a is less moisture permeable than the coating layer at the position of the second coating layer zone 20b. As mentioned above, such an embodiment is advantageous because the cellulose layer can be bonded in an optimal manner at the position of the second coating layer zone 20b and the moisture permeability is minimal at the position of the first coating layer zone 20a. Thus, the cellulose packaging material contains optimal properties for further processing and functioning according to the intended purpose. Therefore, based on the above, a person skilled in the art will understand that the amount of coating material can be controlled in different ways. On the one hand, the amount of coating layer material can be controlled using the dimensions and / or the shape of the recesses. On the other hand, the amount of coating layer material can be controlled by changing the number of recesses.It will furthermore be clear that controlling the amount of coating layer material is also possible by a combination of controlling the size and number of the recesses. According to a preferred embodiment, the recesses are arranged on the grid roller along a number of rows. A row is formed, for example, by a number of recesses located in the same line, the line being parallel to the axis of the grid roller 30 and extending between the two outer ends of the grid roller 30. A row comprises a number of recesses. It will be clear that the number of recesses per row depends on the size of the grid roller. To be able to better quantify the number of recesses, in the present application reference is made to the number of recesses per running centimeter, abbreviated LPCM, as seen along the outer surface of the grid roller. Preferably, a minimum of 8 recesses per running centimeter, i.e. 8 LPCMs, are arranged. Preferably, a maximum of 240 recesses per running centimeter, i.e. 240 LPCMs, are arranged. As mentioned above, the size and / or the form of the recesses can be modified in order to control the amount of coating layer material applied. The recesses are preferably a minimum of 3 cm of applied coating layer material per square meter of the cellulose layer 10. 3 In other words, the recess preferably has a total volume of at least 5 cm 3 / m 2 According to one embodiment, the grid roller has 240 LPCMs, i.e. 240 recesses per centimeter of travel, which are a minimum of 3 cm 3 / m 2 of joint volume, more preferably a minimum of 5 cm 3 / m 2 The inventors have determined that in such a preferred embodiment, the junction volume is at most 9 cm 3 / m 2 According to a further preferred embodiment, the grid roller has a minimum length of 40 cm 3 / m 2 of joint volume, more preferably a minimum of 70 cm 3 / m 2 The inventors have determined that in such a preferred embodiment, the junction volume is up to 120 cm3 / m 2 It has been found that the number of recesses also limits their size in practice. Thus, it will be clear that a grid roller with 240 LPCMs has smaller recesses compared to a grid roller with 8 LPCMs when the same amount of coating layer material has to be applied. According to further exemplary embodiments, the grid roller comprises 30, 60, 80, 100 or 140 LPCMs. According to preferred embodiments, the recesses of grid rollers with 30, 60, 80, 100 or 140 LPCMs have a minimum bond volume of 15 cm2, respectively. 3 / cm 2 , 11cm 3 / cm 2 , 8cm 3 / cm 2 , 5.5cm 3 / cm 2 , 4cm 3 / cm 2 and preferably each has a minimum of 40 cm 3 / cm 2 , 17cm 3 / cm 2 , 13cm 3 / cm 2 , 12cm 3 / cm 2 , 8cm 3 / cm 2 Each has a minimum volume of 40 cm 3 / cm 2 , 17cm 3 / cm 2 , 13cm 3 / cm 2 , 12cm 3 / cm 2 , 8cm 3 / cm 2 For example, a grid roller having 30, 60, 80, 100, or 140 LPCMs each has a weight of 13.5 g / m 2 , 8g / m 2 , 5g / m 2 , 4.3g / m 2 , 3.5g / m 2 is applied to the cellulose layer.

[0058] It will be clear that the position of the grid zone portions 36a, 36b must be set according to the intended purpose of the cellulose packaging material. Furthermore, it will be clear that further grid zone portions, for example a third grid zone portion (not shown), may be provided. The third grid zone portion may thus be applied with an amount of coating layer material that is, for example, between the amount of the first grid zone portion and the amount of the second grid zone portion. As mentioned above, the coating layer hardens when it dries. When the coating layer dries and the cellulose packaging material is then folded, cracks appear in the coating layer. These cracks are moisture permeable, which may cause leakage in the cellulose packaging material at the crack location. By applying an intermediate amount of coating layer material at the fold location, for example the third grid zone portion, relative to the first and second grid zones, the possibility of the coating layer cracking is reduced and, ultimately, moisture is stopped. The cellulose packaging material may thus be optimally produced according to its intended purpose.

[0059] 4 shows a perspective view of a grid roller 30 according to a further preferred embodiment. The cellulose layer 10 is pressed against the grid zone 36 of the grid roller 30 using a pressing cylinder 50. Pressing the cellulose layer 10 against the grid zone 36 allows the coating layer material to be applied in an advantageous manner.

[0060] The pressing cylinder 50 is rotatable about an axis (not shown) and, in the illustrated embodiment, is movable in the height direction. Specifically, the pressing cylinder 50 is movably connected to a camshaft 70 via a hopper mechanism 60.

[0061] The camshaft 70 is rotatable about an axis C. The camshaft 70 includes an eccentric camshaft portion 71. The eccentric camshaft portion 71 extends eccentrically outward from an outer surface of the camshaft 70. The eccentric camshaft portion 71 rotates with the camshaft 70. The camshaft 70 is preferably drivable by an actuator, such as a servo motor.

[0062] According to the illustrated embodiment, the hopper mechanism 60 includes a frame 61. The pressing cylinder 50 is mounted on the frame 61 for rotation about an axis B. The frame 61 is further connected to the camshaft 70 via a tilt mechanism. The tilt mechanism includes a tilt bar 62. The tilt bar 62 is tiltable about a tilt axis 63 and includes two tilt bar arms extending in two opposite directions from the tilt axis 63. A first arm of the tilt bar 62 is connected to the frame 61. A second arm of the tilt bar 62 extends to a position below the camshaft section and to a position in the plane of motion of the camshaft section 71. By rotating the camshaft 70, the camshaft section 71 serves as a stop surface for moving the second arm downwards during its rotation. The downward movement of the second arm rotates the tilt bar about the tilt axis 63, which causes the first arm to move upwards. The upward movement of the first arm then lifts the frame 61 upward, thereby finally lifting the pressing cylinder 50. Lifting the pressing cylinder breaks the contact between the cellulose layer and the grid roller 30. In other words, the rotational movement of the camshaft 70 is converted into an up-down movement of the hopper mechanism, thereby interrupting the contact between the cellulose layer and the moving endless surface. It will be clear that the up-down movement is only temporary due to the eccentric camshaft portion, i.e. the interruption is realized as long as the camshaft portion 71 contacts the first arm of the tilt bar 62. Such a camshaft and hopper mechanism can be integrated retroactively and in a relatively simple manner into existing coating layer application devices. Moreover, by providing multiple camshaft portions, the frequency of interruption can be further controlled. The first camshaft portion and the second camshaft portion can, for example, be oriented at right angles to each other. The contact moment between the camshaft portion and the second arm of the tilt bar is at least partially determined by the rotational speed of the camshaft. The frequency of interruption can therefore be controlled by adjusting the mutual angles between the different camshaft sections.

[0063] It will be further clear to the skilled person that there are different ways of breaking the contact between the cellulose layer 10 and the grid roller 30. Thus, it has been found that the interruption can also be achieved by interrupting the grid zone 36, in that for example the grid roller 30 is provided with a blank zone in which no coating layer material is applied to the cellulose layer 10.

[0064] 5 shows a grid roller provided with a blank zone 36c. The grid zone 36 is further shown for illustrative purposes as an unrolled top view of the outer surface of the grid roller 30. The cellulose layer 10 with a coating layer obtained by contacting the cellulose layer 10 with the illustrated grid zone is also shown as is the unrolled outer surface.

[0065] In other words, Figure 5 shows the result of interrupting the application of the coating layer 10. When the application is interrupted, a zone 20c is created on the cellulose layer where no coating material is present. The zone 20c where no coating layer material is present strengthens to a great extent the adhesive connection that has been or will be applied thereto. The strengthened adhesive connection allows the cellulose packaging material to be used for more, larger and / or heavier products.

[0066] Figures 3 and 5 further show that the coating layer 10 is preferably applied in a pattern. The pattern of the coating layer preferably comprises repeating elements. The repeating elements are even more preferably at a uniform distance from each other, thereby resulting in a pattern of lines and intermediate areas. It is even more preferred that the perpendicular distance between the repeating elements is at most four times greater than the width of the repeating elements. It is even more preferred that the perpendicular distance is at most three times or at most two times the width of the repeating elements. It has further been found that when applying a coating layer with a uniform pattern, such as the pattern of parallel lines at a uniform mutual distance shown in Figure 5, the lines nevertheless do not have a completely uniform width after application of the coating layer. In other words, the lines have a small variation. This effect is particularly achieved in somewhat rough types of paper, such as for example unbleached paper with a high proportion of long fibers. Such types of paper typically have a surface roughness of 100-250 mL / min (ISO8791-2) on the first side, such as 150-200 mL / min. Such slight variations give the appearance that the pattern is actually located in the paper, rather than on top of it. Watermarks can also be placed in this manner instead of and / or in addition to regularly repeating elements.

[0067] Figure 6A shows a method 1000 for applying a coating layer to a cellulosic packaging material for the purpose of setting the moisture vapor transmission rate of the packaging material. Figure 6B shows the method 1000 in a coating layer application device according to a preferred embodiment.

[0068] In a first step, the method includes a step 1100 of providing a cellulose layer 10 having a first side and a second side. As already shown in Figures 1, 2 and 4, the cellulose layer 10 can be fed in a number of ways and from a number of directions. The method further includes a step 1200 of providing a moving endless surface including a grid zone having a number of recesses. In the illustrated embodiment, the moving endless surface is a grid roller 30. The grid roller 30 is at least partially immersed in a container for the coating layer material. Here, the grid roller 30 takes up a predetermined amount of the coating layer material in the number of recesses of the grid zone in 1300. The taking up of the coating layer material is performed through the inlet openings of the recesses 37, i.e. at the surface. Then, in 1400, a predetermined amount of the coating layer material is held in the number of recesses. Optionally, a blade 80 is provided, the peripheral edge of which is placed against or substantially against the outer surface of the grid roller 30 in order to scrape off excess portions of the entrained coating layer material from the outer surface. The grid zone is then brought into contact with the first surface of the cellulose layer 10 at 1500. In FIG. 6B, the grid zone is brought into contact via the lower surface of the cellulose layer. However, it will be clear that the grid zone can also be located on the upper surface of the cellulose layer. At 1600, a predetermined amount of coating layer material is applied from the recesses when the cellulose layer is brought into contact with the grid zone. Thus, in other words, the coating layer material also leaves the recesses through the inlet openings of the recesses. Thus, the entrainment of the coating layer material into the recesses and the application of the coating layer material from the recesses are performed via the same surface of the recesses, i.e. at the surface location. This results in the formation of a coating layer on the cellulose layer 10 with a predetermined amount of coating layer material at 1700.

[0069] Thanks to the above-mentioned improved controllability of the application of the coating layer material, the method and the device allow existing devices to be utilized in a more flexible way. Thus, the coating layer material can be kept in the device and applied at a lower temperature, for example 120°C. This advantage is based on the insight that the coating layer material emits a very unpleasant odor at high temperatures, for example 150°C. By keeping the coating layer material at a lower temperature, preferably at a maximum of 130°C, more preferably at a maximum of 120°C, the area around the device becomes more accessible and comfortable. Furthermore, less energy is required to heat the coating layer material to 120°C compared to 150°C. The improved application of the coating layer material also gives the user more freedom to use different pressures, for example more pressure or less pressure, compared to known systems or devices.

[0070] Also, an improved application of the coating layer material can be used to apply a predetermined amount of coating layer material to the second side. A predetermined amount of coating layer material can be applied to both the first and second sides of the cellulose layer 10. In other words, a predetermined amount of coating layer material can be applied to the first and / or second sides of the cellulose layer. For this purpose, a first moving endless surface as shown in FIG. 1 can be provided and a second moving endless surface (not shown) can be provided. The first moving endless surface 35 can, for example, apply the coating layer material to the first side as described above. The second endless surface (not shown) is provided to apply a predetermined amount of coating layer material to the second side. The amount of coating layer material applied by the first moving endless surface on one side and by the second moving endless surface on the other side is not necessarily the same. The first and second moving endless surfaces can, for example, be provided with different grid zones from each other. It is noted that the type of coating layer material on the first and second sides can be different. Thus, experiments have shown that an oil-based coating layer material can be provided on a first surface and a water-based material on a second surface. The second moving endless surface is preferably located downstream of the first moving endless surface, as viewed in the direction of motion of the coating layer 10.

[0071] 7A1, 7A2, 7B1, and 7B2 show perspective views of a cellulose package 100 made from a cellulose packaging material having a coating layer 20 applied using the method 1000 shown in FIGS. 6A and 6B.

[0072] Figures 7A1 and 7A2 show the front and back sides of a cellulose packaging formed from a cellulose packaging material. The packaging shown in Figures 7A1 and 7A2 is a bag with a coating layer 20a on the inside of the bag. As mentioned above, the method allows the coating layer material not to be applied to a portion of the packaging material. The zone 20c where the coating layer material is not present significantly strengthens the adhesive connection that has been or will be applied thereto. The zone 20c allows the cellulose packaging material to be glued to itself or to a further packaging material. In the preferred embodiment shown, the zone 20c provides improved adhesion and thus reinforces the bottom, thus forming a bag with a strong bottom. Figures 7B1 and 7B2 show the front and back sides of a cellulose packaging formed from a cellulose packaging material. Similar to Figures 7A1 and 7A2, Figures 7B1 and 7B2 show a bag. However, Figures 7A1, 7A2 and 7B1, 7B2 differ in that the coating layer 20a is arranged on the outside of the bag in Figures 7B1 and 7B2. It will be clear to those skilled in the art that further packaging, such as, for example, cardboard boxes for cakes, pastries or hamburgers, holders such as coffee cup holders or, for example, carrier trays for eggs, can be manufactured from the cellulose packaging material made according to the above-mentioned method. It will be further clear that the coating layer can be applied both inside and outside the bag in the illustrated context of Figures 7A1, 7A2, 7B1, 7B2.

[0073] Based on the above description, a person skilled in the art will understand that the present invention can be embodied in different ways and based on different principles. The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments and drawings are purely illustrative and merely serve to deepen the understanding of the present invention. Therefore, the present invention is not limited to the embodiments described herein, but is defined in the claims.

Claims

1. A method (1000) for applying a coating layer to a cellulose packaging material for the purpose of setting the moisture vapor transmission rate of said material, said method comprising the steps of: - providing (1100) a cellulose layer (10) having a first surface and a second surface; - providing (1200) a moving endless surface (35) comprising a grid zone (36) having a number of recesses (37); - incorporating (1300) a quantity of coating layer material into a number of recesses (37) of said grid zone (36); - retaining (1400) said amount of coating layer material in said plurality of recesses (37); - contacting (1500) said grid zone (36) with a first side of said cellulose layer (10); - applying (1600) said amount of coating layer material from said plurality of recesses (37) onto a first side of said cellulose layer (10); - forming (1700) a coating layer (20) on a first side of said cellulose layer (10) using said amount of coating layer material; A method comprising:

2. 2. The method of claim 1, wherein the grid zone (36) comprises a first grid zone portion (36a) and a second grid zone portion (36b), the first grid zone portion (36a) and the second grid zone portion (36b) comprising a plurality of first recesses and a plurality of second recesses, respectively, the plurality of first recesses and the plurality of second recesses capturing, retaining and applying a first predetermined amount of coating layer material and a second predetermined amount of coating layer material, respectively, the first predetermined amount of coating layer material being different from the second predetermined amount of coating layer material.

3. 3. The method according to claim 1 or 2, wherein the moving endless surface (35) is further provided with a blank zone on the first side of the cellulose layer (10) where no coating layer material is applied.

4. The dimensions of the plurality of recesses are such that the coating layer has a thickness of 10 to 12 g / m ２ More preferably, it is in the range of 8 to 10 g / m ２ and most preferably in the range of 1 to 8 g / m ２ The method of claim 1 , wherein the substrate is dimensioned to have a weight in the range of

5. 2. The method of claim 1, wherein contacting the grid zone (36) with the first side of the cellulose layer (10) comprises pressing the first side of the cellulose layer (10) against a grid zone (36) of the moving endless surface.

6. The method of claim 5, further comprising interrupting the application of the quantity of coating layer material to the first side of the cellulose layer (10).

7. 7. The method of claim 6, wherein interrupting application of the coating layer to the first side of the cellulose layer (10) comprises interrupting contact of the grid zone (36) with the first side of the cellulose layer (10).

8. 8. The method according to claim 6 or 7, wherein interrupting the application of the quantity of coating layer material to the first side of the cellulose layer is performed using a hopper mechanism (60) movably connecting the press cylinder to a camshaft (70), the camshaft (70) being configured to translate its rotational movement into an up and down movement of the hopper mechanism, whereby contact between the cellulose layer and the moving endless surface is interrupted.

9. The method of claim 1 , wherein the coating layer comprises an oily compound, such as paraffin or vegetable oil.

10. The method of claim 1 , wherein the coating layer is applied in a pattern.

11. The method of claim 1 , wherein loading the quantity of coating layer material into a plurality of recesses (37) of the grid zone (36) comprises loading the coating layer material into the recesses in a capillary manner.

12. The coating layer has a thickness of 15 to 200 g / m ２ / day, preferably 15 to 180 g / m ２ / day, more preferably 15 to 150 g / m ２ / day, and even more preferably 15 to 120 g / m ２ The method of claim 1, having a moisture permeability of 100 / day.

13. - providing a further moving endless surface with a grid zone having a plurality of recesses, - incorporating a quantity of coating layer material into a number of recesses in a grid zone of said further moving endless surface; - holding said amount of coating layer material in a number of recesses of said further moving endless surface; - contacting said grid zone with the second face of said cellulose layer; - applying said amount of coating layer material onto a second side of said cellulose layer from a plurality of recesses of said further moving endless surface; - forming a further coating layer on a second side of the cellulose layer using said amount of coating layer material; The method of claim 1 further comprising:

14. 1. A coating layer application device for setting the moisture permeability of a cellulose packaging material, the coating layer application device comprising a moving endless surface (35) for applying a coating layer to the cellulose packaging material, the cellulose packaging material comprising a cellulose layer having a first side and a second side, the cellulose layer moving in a direction of movement through the coating layer application device, the moving endless surface (35) comprising a grid zone (36) having a plurality of recesses (37), the plurality of recesses (37) being: - incorporating a quantity of coating layer material into a number of recesses (37) of said grid zone (36); - holding said amount of coating layer material in said plurality of recesses (37); It is structured as follows: the moving endless surface is positionable adjacent to a first side of the cellulose layer (10); and - applying said amount of coating layer material onto a first side of said cellulose layer (10) from said plurality of recesses (37); - forming a coating layer (20) on a first side of said cellulose layer (10) using said amount of coating layer material; The coating layer application device further comprises:

15. 15. The coating layer application apparatus of claim 14, wherein the grid zone (36) comprises a first grid zone portion (36a) and a second grid zone portion (36b), the first grid zone portion (36a) and the second grid zone portion (36b) comprising a plurality of first recesses and a plurality of second recesses, respectively, the plurality of first recesses and the plurality of second recesses capturing, retaining and applying a first predetermined amount of coating layer material and a second predetermined amount of coating layer material, respectively, the first predetermined amount of coating layer material being different from the second predetermined amount of coating layer material.

16. 16. The coating layer application device according to claim 15, wherein the moving endless surface (35) is further provided with a blank zone in which no coating layer material is applied to the first side of the cellulose layer (10).

17. The size of the recess is such that the coating layer is 10 to 12 g / m ２ More preferably, it is in the range of 8 to 10 g / m ２ and most preferably in the range of 1 to 8 g / m ２ 15. The coating layer applicator of claim 14, dimensioned to have a weight in the range of

18. 18. The coating layer application device according to any one of claims 14 to 17, further comprising a pressing cylinder (50) configured to press the cellulose layer against a surface of the moving endless surface (35) to achieve contact between the cellulose layer and the grid zone.

19. The coating layer application apparatus of claim 18, further comprising a hopper mechanism (60) movably connecting the pressure cylinder to a camshaft (70), the camshaft (70) configured to convert its rotational motion into up and down motion of the hopper mechanism, thereby interrupting contact between the cellulose layer and the grid zone.

20. 16. The coating layer application apparatus of claim 15, wherein the moving endless surface is a grid roller.

21. The coating layer application apparatus of claim 15, further comprising a coating layer material compartment containing a volume of coating layer material, and the grid roller is partially immersed in the volume of coating layer material.

22. The coating layer application apparatus further comprising a further moving endless surface having a grid zone having a plurality of recesses, the plurality of recesses being: - incorporating a quantity of coating layer material into a number of recesses in a grid zone of said further moving endless surface, - holding said amount of coating layer material in a number of recesses in said further moving endless surface It is structured as follows: the further moving endless surface is positionable adjacent to the second face of the cellulose layer (10); and - applying said amount of coating layer material from said plurality of recesses onto the second side of said cellulose layer (10); - forming a further coating layer on the second side of said cellulose layer (10) using said amount of coating layer material; The coating layer application apparatus of claim 14, further configured to:

23. A grid roller for use as a moving endless surface in the method of claim 1, optionally in the apparatus of claim 14, said grid roller having a surface at least partially provided with grid zones comprising a plurality of recesses configured to take up respective predetermined amounts of coating layer material and then apply said coating layer material to the cellulose layer.

24. 15. A cellulose packaging material, wherein a coating layer for setting the moisture permeability of said cellulose packaging material is applied according to the method of claim 1, preferably by means of an apparatus according to claim 14.

25. 25. A cellulosic packaging (100) for food products, such as bread, baked goods, vegetables, fruits, cheese, or meat, or non-food products, said cellulosic packaging integrally manufactured from the cellulosic packaging material of claim 24.

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