Method for producing a packaging material, and packaging material

Abstract

The invention relates to a method for producing a packaging material comprising at least one relief-like structured layer (1), wherein the method comprises the following steps: (a) providing a base material (2), which base material (2) is paper, (b) plastically shaping the base material (2) by means of an embossing device to form the structured layer (1), wherein: the embossing device comprises multiple embossing sections (4) so that the structured layer (1) has multiple shaped regions (3) formed by the embossing sections; the base material (2) is paper having an elongation at break in the machine direction of at least 5% and an elongation at break in the transverse direction of at least 5%; the shaping in step (b) is carried out at a temperature between 10°C and 40°C; and the base material (2) has a water content between 5% and 9% during shaping in step b). The invention also relates to a shipping material per se.

Description

[0001] METHOD FOR PRODUCING A PACKAGING MATERIAL AND PACKAGING MATERIAL

[0002] The present invention relates to a method for producing a packaging material and to a packaging material as such.

[0003] Packaging materials are known in the art, for example, for mailing goods. Typically, either cardboard boxes or shipping envelopes, with or without cushioning material, are used here. The latter are primarily used for packaging and shipping smaller items that do not require a large amount of packaging. Padded shipping envelopes typically consist of a paper sleeve and a layer of bubble wrap, which is made of a plastic material. The sleeve provides privacy and stability, while the bubble wrap provides a good cushioning effect without significantly increasing the volume of the package.

[0004] Due to efforts to reduce the amount of plastic in packaging materials, a replacement for bubble wrap would be desirable, but so far no materials are known that offer comparable properties and can still be produced in the most energy-efficient way possible. An alternative to the aforementioned shipping envelopes is the use of cardboard packaging, which is padded with, for example, crumpled paper or other plastic-free cushioning materials. However, this significantly increases the shipping volume, which in turn has a negative impact on the energy consumption during transport, so that the positive effect of omitting the plastic material is at least partially relativized. It would therefore be desirable to create a process that allows the production of plastic-free packaging materials that have similar cushioning properties to bubble wrap while still being thin.The production should also be able to take place with the addition of as little energy as possible, in particular without any energy in the form of steam and / or heat.

[0005] An object of the present invention can therefore be seen in achieving this goal. In particular, an object of the present invention can be seen in providing a method for producing a packaging material that has reduced energy consumption compared to the prior art and is plastic-free. A further object of the invention can be seen in providing a corresponding packaging material as such.

[0006] The invention therefore particularly relates to a method for producing a packaging material having at least one structural layer with an embossed structure. The structural layer can be used as such as a packaging material, but it can also be used in a layered composite.

[0007] The process preferably uses paper, in particular kraft paper, as the base material. In the process according to the invention, the base material is subjected to plastic deformation in a known manner. The deformation takes place in particular by means of an embossing device which has a plurality of embossing sections and is configured such that, after deformation, the base material has a plurality of shaped regions formed by the embossing sections. Different devices can be provided to form the shaped regions, for example two counter-rotating embossing rollers or two corresponding embossing plates between which the base material is introduced, subjected to compression, and thereby deformed. In particular, full contact pressing of the base material takes place in the embossing device.For this purpose, the embossed sections can be formed by a die section and a geometrically corresponding male section, wherein during forming, each male section is transformed into a corresponding die section, and the base material to be formed is arranged between the two sections. Completely unexpectedly and surprisingly, it has now been discovered within the scope of the present invention that a packaging material suitable for achieving the above-mentioned objectives can be produced by plastically forming paper as the base material. The forming can take place essentially without external heat input, in particular when the base material is paper that has an elongation at break in the machine direction (MD) of at least 5% and an elongation at break in the transverse direction (CD) of at least 5%. The elongation at break can be determined, for example, according to the ISO 1924-3:2005 standard.

[0008] In specific embodiments of the invention, the base material may have an elongation at break of at least 8% in the machine direction and / or in the transverse direction.

[0009] In a preferred embodiment, the base material has an elongation at break of at least 9% in the machine direction and / or in the transverse direction.

[0010] The process specifically provides for the plastic forming of the base material to take place at a temperature between 10°C and 40°C. The absolute water content of the base material during forming can be between 5% and 20%. In particular, the absolute water content of the base material during forming can be between 5% and 15%, in special embodiments between 5% and 12% or between 5% and 9%. Adjustment of the water content by spraying, atomizing, printing, or other suitable means is possible.

[0011] The absolute water content in % can particularly refer to the weight percent relative to the dry mass of the base material. The absolute water content can also be referred to as absolute moisture.

[0012] The process is preferably carried out in an industrial embossing device. The embossing device can comprise, for example, a machine frame and a conveyor system for supplying and removing the base material. The base material can be provided in roll form. Optionally, other devices, such as a cutting station, can be connected to the embossing device.

[0013] The process according to the invention provides, on the one hand, a plastic-free packaging material and, on the other hand, enables considerable energy savings compared to the production of conventional forming processes for paper-based materials, which are usually carried out at high temperatures and high water contents.

[0014] Further advantages of the present invention may be:

[0015] - Independence from fossil fuels

[0016] - no use of raw materials from fossil sources

[0017] - reduced equipment requirements in the production plant due to the elimination of the heating / steam system

[0018] - reduced investment expenditure on new equipment

[0019] - reduced footprint of new plants

[0020] - reduced energy requirements for the transport of products packaged with the packaging materials according to the invention

[0021] - no paper-plastic composites and therefore easier recycling

[0022] In the context of the present invention, "external heat supply" specifically means that no additional or intentional heat supply occurs. The embossing device or the embossing areas typically heat up slightly during operation, but this is not considered "external heat supply" within the meaning of the present invention.

[0023] In the method according to the invention, the temperature at which the forming takes place can in particular be the temperature which the surface of the embossed areas has during the forming step.

[0024] Before the forming step, the base material can be essentially flat. For example, it can be rolled material that is processed in the method according to the invention. In particular, a structural layer can be produced in which the base material is permanently plastically deformed.

[0025] The embossing device can comprise embossing plates, allowing flatbed embossing. Alternatively, the embossing device can comprise embossing rollers, allowing rotary roller embossing.

[0026] The geometry of the embossed areas is not particularly restricted. For example, they can be designed so that the embossed sections have a knob-shaped geometry, particularly hemispherical or spherical segments. However, the embossed areas can also be prismatic, truncated pyramid-shaped, or truncated cone-shaped.

[0027] Embossed areas or formed areas in the structural layer can be directly adjacent to one another, but flat areas can also be arranged between them in which the base material is not subjected to any forming.

[0028] The molded areas can have a depth of between 1 mm and 20 mm, in particular between 5 mm and 20 mm. The depth is, in particular, the maximum dimension of the molded areas in the thickness direction of the structural layer. The molded areas can form extensions that protrude essentially orthogonally from the surface plane of the structural layer.

[0029] Where applicable, the burst strength of the base material is at least 380 Pa. Where applicable, the burst strength of the base material is between 380 kPa and 1000 kPa. The burst strength can be determined, for example, according to the ISO 2758:2014 standard.

[0030] Where appropriate, the tensile fracture energy of the base material in the machine direction is at least 150 J / m 2 , in particular at least 200 J / m 2 , preferably at least 400 J / m 2 Where appropriate, the tensile fracture energy of the base material in the transverse direction is at least 150 J / m 2, in particular at least 200 J / m 2 , preferably at least 300 J / m 2 The tensile fracture energy of the base material in the machine direction can be between 150 J / m 2 and 600 J / m 2 The tensile fracture energy of the base material in the transverse direction can be between 150 J / m 2 and 500 J / m 2 lay.

[0031] Tensile energy absorption can be determined, for example, according to ISO 1924-3:2005.

[0032] Optionally, the tensile strength of the base material in the machine direction is at least 5.0 kN / m, in particular at least 7.0 kN / m, preferably at least 10 kN / m or at least 13 kN / m. Optionally, the tensile strength of the base material in the transverse direction is at least 3.0 kN / m, in particular at least 5.0 kN / m, preferably at least 6.0 kN / m.

[0033] The tensile strength of the base material in the machine direction may, if appropriate, be between 5.0 kN / m and 20 kN / m. The tensile strength of the base material in the transverse direction may, if appropriate, be between 3.0 kN / m and 10.0 kN / m.

[0034] Tensile strength can be determined, for example, according to ISO 1924-3:2005.

[0035] Optionally, the tear resistance of the base material in the machine direction is at least 500 mN, in particular at least 700 mN, preferably at least 1000 mN or at least 1200 mN. Optionally, the tear resistance of the base material in the transverse direction is at least 500 mN, in particular at least 700 mN, preferably at least 1000 mN or at least 1200 mN or even at least 2000 mN. Optionally, the tear resistance of the base material in the machine direction and / or in the transverse direction is between 500 mN and 2500 mN.

[0036] Tear strength can be determined, for example, according to ISO 1974:2012. The basis weight of the base material may be between 50 g / m 2 and 180 g / m 2 In particular, the grammage of the base material is at least 80 g / m 2 . The grammage can be determined, for example, according to the ISO 536:2012 standard.

[0037] The structural layer produced in a process according to the invention can be used as a packaging material without further processing steps. However, additional steps can be provided in which the structural layer is further processed to form a packaging material.

[0038] For example, a flat layer consisting of the base material can be bonded to a structural layer to form a flat layer-structural layer composite. In such a flat layer-structural layer composite, the molded areas on one side of the structural layer can be bonded to the flat layer via an adhesive. Optionally provided flat areas can also be bonded to a flat layer.

[0039] A flat layer-structure layer composite can optionally be bonded to another flat layer on the side where the structural layer is exposed. Several flat layer-structure layer composites, each consisting of a flat layer and a structural layer, can also be bonded together. For example, the following layer sequences can be formed in a method according to the invention: PS; PSP; PSPSP; PSPSPSP, where P denotes a flat layer and S a structural layer.

[0040] The adhesive for producing a flat layer-structural layer composite can be selected from one or more of the following adhesives: water-based adhesive; solvent-based adhesive; solvent-free adhesive; starch-based adhesive; protein-based adhesive; polymer dispersion adhesive;

[0041] Polymer solvent adhesive; resin adhesive; electron beam-activated adhesive; hot-melt adhesive; reactive adhesive, especially two-component reactive adhesive. Adhesives that do not require heat for curing or solidification can be advantageous.

[0042] Further steps may be required to create a packaging material, such as printing, folding, cutting, bending, and gluing.

[0043] In particular, the invention also relates to a packaging material produced by a method according to the invention. A packaging material can consist of or comprise a structural layer. The structural layer, in turn, can be formed from a base material.

[0044] It can be provided that the base material is kraft paper with an elongation at break in the machine direction of at least 5% and an elongation at break in the transverse direction of at least 5%, wherein the structural layer has a plurality of forming regions. The base material can have the properties described in connection with the method according to the invention.

[0045] The packaging material may be in the form of a box, a shipping bag or other packaging.

[0046] The invention particularly relates to a method for producing a packaging material with at least one relief-like structural layer, the method comprising the following steps:

[0047] - Providing a base material, wherein the base material is paper, in particular kraft paper,

[0048] - plastically forming the base material with an embossing device to form the structural layer, wherein the embossing device has a plurality of embossed sections, so that the structural layer has a plurality of shaped areas formed by the embossed sections,

[0049] It is preferably provided that the base material has an elongation at break in the machine direction of at least 5%, in particular at least 8%, and an elongation at break in the transverse direction of at least 5%, in particular at least 8%, that the forming takes place at a temperature of between 10°C and 40°C, and that the base material has an absolute water content of between 5% and 20%, in particular between 5% and 9%, during forming.

[0050] Where appropriate, the bursting strength of the base material shall be at least 380 kPa or between 380 kPa and 00 kPa.

[0051] Where appropriate, it is intended that the tensile fracture energy of the base material in the machine direction is at least 150 J / m 2 , in particular at least 200 J / m 2 , and that the tensile fracture energy of the base material in the transverse direction is at least 150 J / m 2 , in particular at least 200 J / m 2 , amounts.

[0052] Where appropriate, it is provided that the tensile strength of the base material in the machine direction is at least 5.0 kN / m, in particular at least 7.0 kN / m, and that the tensile strength of the base material in the transverse direction is at least 3.0 kN / m, in particular at least 5.0 kN / m.

[0053] Where appropriate, it is provided that the tear resistance of the base material in the machine direction is at least 500 mN, in particular at least 700 mN, and that the tear resistance of the base material in the transverse direction is at least 500 mN, in particular at least 700 mN.

[0054] Where appropriate, it is intended that the base material is essentially flat before forming.

[0055] Where appropriate, it is provided that the embossing sections are formed by a die section and a male section that can be inserted or is inserted into the die section.

[0056] Optionally, the embossing device comprises two embossing rollers, with the male die sections arranged on the first embossing roller and the female die sections arranged on the second embossing roller, or the embossing device comprises two embossing plates, with the male die sections arranged on the first embossing plate and the female die sections arranged on the second embossing plate. Optionally, the embossing sections are separated by flat sections, so that adjacent forming regions of the formed base material are separated from one another by flat sections.

[0057] Where appropriate, it is provided that the shaped areas, in particular relative to the flat areas, have a depth of between 1 mm and 20 mm.

[0058] Where appropriate, it is provided that the shaped regions have a geometry selected from the following list: spherical segment-shaped, prismatic, truncated pyramid-shaped, truncated conical-shaped, wherein the shaped regions are preferably spherical segment-shaped.

[0059] If necessary, it is provided that flat areas are arranged between adjacent forming areas in the machine direction and in the transverse direction of the base material.

[0060] Where appropriate, the procedure may include the following further steps:

[0061] - Providing a substantially flat planar layer formed from the base material, and

[0062] - connecting the structural layer obtained in step with the planar layer to obtain a planar layer-structural layer composite.

[0063] Where appropriate, it is provided that the planar layer is connected to planar areas of the structural layer and / or that the planar layer is connected to shaped areas of the structural layer.

[0064] If necessary, it is provided that the resulting flat layer-structure layer composite is connected to another flat layer and / or another structure layer.

[0065] Where appropriate, an adhesive selected from one or more of the following is used to bond layers: water-based adhesive; electron beam-activated adhesive; hot-melt adhesive; reactive adhesive, in particular a two-component reactive adhesive.

[0066] If necessary, it is provided that an envelope, in particular an envelope or a shipping packaging, is formed from the structural layer and / or the flat layer-structural layer composite.

[0067] The invention also relates in particular to a packaging material, in particular obtained in a process having one or more of the features mentioned here, comprising or consisting of a structural layer consisting of a base material, wherein the base material is kraft paper with an elongation at break in the machine direction of at least 5% and with an elongation at break in the transverse direction of at least 5%, wherein the structural layer has a plurality of embossed shaped areas.

[0068] Where appropriate, adjacent mold areas are separated from each other by plan areas.

[0069] Further features of the invention emerge from the patent claims, the figures and the description of the embodiment.

[0070] The invention is explained in detail below using an exemplary embodiment. This embodiment merely serves to illustrate advantageous aspects of the invention and is not intended to limit the scope of protection defined by the patent claims.

[0071] They show:

[0072] Fig. 1 is an illustration of a forming step according to an embodiment of a method according to the invention;

[0073] Fig. 2 is a schematic detailed view of a structural layer obtained by a method according to the invention;

[0074] Fig. 3 is a schematic representation of a portion of the packaging material from Fig. 2; and Fig. 4 is a schematic detailed view of a planar layer-structure layer composite obtained by a method according to the invention.

[0075] Unless otherwise stated, the figures show the following features: structural layer 1, base material 2, forming area 3, embossing section 4, die section 5, male die section 6, flat section 7, embossing roller 8, first embossing roller 8', second embossing roller 8". Flat area 9, depth 10, machine direction 11, flat layer 12, flat layer-structural layer composite 13, adhesive area 14, width 15, transverse direction 16.

[0076] Fig. 1 shows an illustration of a forming step according to an embodiment of a method according to the invention. The flat base material 2 was introduced into an embossing device and embossed using two embossing rollers 8. The embossing rollers 8 are each equipped with a plurality of embossing sections 4, with the first embossing roller 8' having die sections 5 and the second embossing roller 8" having male sections 6. Flat sections 7 are arranged between the embossing sections 4, within which no forming or embossing of the base material 2 takes place.

[0077] The forming process thus produced a structural layer 1 which has shaped sections 3 corresponding to the embossing sections 4 on the embossing rollers 8.

[0078] The forming in this process took place at a temperature of about 33°C (average surface temperature of the embossing rollers 8) and the base material 2 had a water content of about 6% of the dry mass.

[0079] In this exemplary embodiment, six base materials with different property profiles were compared, which are listed in Tables 1-6 below. Tables 1-5 show base materials according to the invention, and Table 6 shows a comparison base material that is not according to the invention. Table 1: Properties of the first base material made of unbleached pulp

[0080] Table 2: Properties of the second base material made of unbleached pulp

[0081] Table 3: Properties of the third base material made of unbleached pulp

[0082] Table 4: Properties of the fourth base material made of bleached pulp

[0083] Table 5: Properties of the fifth base material made of bleached pulp Table 6: Properties of a comparative base material (not according to the invention)

[0084] A structural layer 1 was obtained from the base materials according to the invention, in which the base material 2 is permanently plastically deformed. The structural layer 1, which was obtained according to the exemplary embodiments, is shown schematically in detail in Fig. 2.

[0085] The structural layer 1 has a plurality of mutually arranged molding regions 3, which in this embodiment are spherical segment-shaped. The width 15 of each molding region 3 is approximately 20 mm, and the depth 10 is approximately 10 mm. Flat sections 9 are arranged between the molding regions 3, in which the base material 2 has not been plastically deformed.

[0086] As can be seen in Fig. 3, the forming regions 3 are arranged in a regular pattern that runs along the transverse direction 16 and along the machine direction 11 of the base material 2.

[0087] It should be noted that structural layer 1 can already be used as a packaging material as such, but further processing steps may also be required. The comparative base material from Table 6 did not allow sufficient plastic deformation to be used as a packaging material. In particular, tearing during the forming process and insufficient dimensional stability of the formed areas were observed.

[0088] Of the base materials according to the invention, those from Tables 1 and 3 are particularly noteworthy, with the base material from Table 1 showing very good suitability for the process according to the invention and the base material from Table 3 showing excellent suitability for the process according to the invention.

[0089] Fig. 4 shows a schematic detailed view of an embodiment of a packaging material according to the invention, which is a three-layer flat layer-structure layer composite 13.

[0090] To form this flat layer-structure layer composite 13, the structural layer 1 was bonded to a flat layer 12 on its top and bottom sides according to the exemplary embodiment described above. The flat layers 12 also consisted of the base material 2, and a water-free adhesive was used as the adhesive. In other embodiments, a water-based adhesive, such as a dispersion adhesive, can also be used. The adhesive areas 14 are located at the contact points between the adjacent layers.

[0091] Such a flat layer-structure layer composite 13 can be used to form a shipping envelope or the like.

Claims

Patent claims 1. A method for producing a packaging material with at least one relief-like structural layer (1), the method comprising the following steps: a. providing a base material (2), the base material (2) being paper, in particular kraft paper, b.plastically forming the base material (2) with an embossing device for forming the structural layer (1), wherein the embossing device has a plurality of embossing sections (4), so that the structural layer (1) has a plurality of forming regions (3) formed by the embossing sections, characterized in that the base material (2) has an elongation at break in the machine direction of at least 5%, in particular at least 8%, and an elongation at break in the transverse direction of at least 5%, in particular at least 8%, that the forming in step (b) takes place at a temperature of between 10°C and 40°C, and that the base material (2) has an absolute water content of between 5% and 20%, in particular between 5% and 9%, during the forming in step (b).

2. Method according to claim 1, characterized in that the bursting strength of the base material (2) is at least 380 kPa or is between 380 kPa and 1000 kPa.

3. Method according to claim 1 or 2, characterized in that the tensile fracture energy of the base material (2) in the machine direction is at least 150 J / m 2 , in particular at least 200 J / m 2 , and that the tensile fracture energy of the base material (2) in the transverse direction is at least 150 J / m 2 , in particular at least 200 J / m 2 , amounts.

4. Method according to one of claims 1 to 3, characterized in that the tensile strength of the base material (2) in the machine direction is at least 5.0 kN / m, in particular at least 7.0 kN / m, and that the tensile strength of the base material (2) in the transverse direction is at least 3.0 kN / m, in particular at least 5.0 kN / m.

5. Method according to one of claims 1 to 4, characterized in that the tear resistance of the base material (2) in the machine direction is at least 500 mN, in particular at least 700 mN, and in that the tear resistance of the base material (2) in the transverse direction is at least 500 mN, in particular at least 700 mN.

6. Method according to one of claims 1 to 5, characterized in that the base material (1) is substantially flat before the forming in step (b).

7. Method according to one of claims 1 to 6, characterized in that the embossing sections (4) are formed by a die section (5) and a male section (6) which can be inserted or is inserted into the die section (5).

8. The method according to claim 7, characterized in that the embossing device comprises two embossing rollers (8), wherein the male portions (6) are arranged on the first embossing roller (8') and the female portions (5) are arranged on the second embossing roller (8"), or that the embossing device comprises two embossing plates, wherein the male portions (6) are arranged on the first embossing plate and the female portions (5) are arranged on the second embossing plate.

9. Method according to one of claims 1 to 8, characterized in that the embossed sections (4) are separated by flat sections (7), so that adjacent forming regions (3) of the formed base material (2) are separated from one another by flat regions (9).

10. Method according to one of claims 1 to 9, characterized in that the shaped areas (3), in particular relative to the flat areas (4), have a depth (10) of between 1 mm and 20 mm.

11. Method according to one of claims 1 to 10, characterized in that the shaped regions (3) have a geometry selected from the following list: spherical segment-shaped, prismatic, truncated pyramid-shaped, truncated conical-shaped, wherein the shaped regions (3) are preferably spherical segment-shaped.

12. Method according to one of claims 1 to 11, characterized in that flat regions (9) are arranged between adjacent forming regions (3) in the machine direction (11) and in the transverse direction of the base material (2).

13. Method according to one of claims 1 to 12, characterized in that the method comprises the following further steps: c. Providing a substantially planar planar layer (12) formed from the base material (2), and d. Joining the structural layer (1) obtained in step (b) to the planar layer (12) to obtain a planar layer-structural layer composite (13).

14. Method according to claim 13, characterized in that the planar layer (12) is connected to planar regions (9) of the structural layer (1), and / or that the planar layer (12) is connected to shaped regions (3) of the structural layer (1).

15. The method according to claim 13 or 14, characterized in that the planar layer-structured layer composite (13) obtained in step (d) is connected to a further planar layer (12) and / or to a further structural layer (1).

16. Method according to one of claims 13 to 15, characterized in that an adhesive selected from one or more of the following is used to bond layers: water-based adhesive; electron beam-activatable adhesive; hot-melt adhesive; reactive adhesive, in particular 2-component reactive adhesive.

17. Method according to one of claims 1 to 16, characterized in that an envelope, in particular a letter envelope or a shipping packaging, is formed from the structural layer (1) and / or from the flat layer-structural layer composite (13).

18. Packaging material, in particular obtained in a process according to one of claims 1 to 17, comprising or consisting of a structural layer (1) consisting of a base material, wherein the base material (2) Kraft paper having an elongation at break in the machine direction of at least 5% and an elongation at break in the transverse direction of at least 5%, wherein the structural layer (1) has a plurality of embossed shaped areas (3).

19. Packaging material according to claim 18, characterized in that adjacent shaped areas (3) are separated from one another by flat areas (9).

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