Mulching film

Abstract

The disclosure relates to a mulching film (2) comprising a base material (1), wherein the base material (1) is made of mechanically and / or chemically processed cellulose fibers derived from wood, rags, grasses or other vegetable sources, wherein the mulching film (2) is partially provided with a reinforcement layer (3), which reinforcement layer (3) has a disintegration time determined in accordance with DIN EN 13432:2000-12 of between 6 months and 18 months, in particular of between 9 months to 15 months. The disclosure also relates to a use of said mulching film.

Description

[0001] Mulching film

[0002] The present invention relates to a mulching film, a use of a mulching film as well as an arrangement of a mulching film on a soil surface.

[0003] In the prior art is has been known to cover soil areas designated for specific purposes, such as agriculture, horticulture, and forestry, with mulching films made of plastics. The intention behind using such mulching films is that growth of pest plants on the covered soil areas can be prevented, whereas the crop plants are allowed to penetrate the mulching film through specifically provided openings, which enables their substantially unimpaired growth. A further advantage provided by mulching films is that the covered soil areas are kept moist, as evaporation of water from the soil surface is hindered by the presence of the film.

[0004] A particular prerequisite for mulching films is that the materials exhibit sufficient strength in both dry and wet state so that the films can withstand the forces exerted on them during their lifetime, which is typically one growth season. For fixation, the mulching films are typically placed on the designated soil surface in the form of elongated strips. The edge areas of these strips are then covered by soil material to weigh the film to the ground. This way, no additional fixation means are required. Commercially available devices for laying out mulching films typically also apply this principle. Different plastics materials have been the materials of choice in the past due to their beneficial properties for the desired purpose, such as tear resistance, water resistance, and durability.

[0005] However, in recent years, many concerns have come up with respect to the use of plastics materials. In particular, the widespread use of non-renewable sources and the limited degradability of these materials have raised considerable concerns. Additionally, governmental regulations and elevated environmental awareness have brought up the need for substitute materials.

[0006] In the attempt to overcome the above-mentioned drawbacks of the prior art, it has been found that mulching films can also be produced from paper without using plastics, especially if certain limitations with regards to the mechanical properties of the paper are met. While these films are durable when not covered by soil, quick degradation has been observed to occur in areas of the film, which are covered by soil material. Thus, alternative ways of fixation have to be used, which do not involve covering the films with soil material. This leads to the drawback that additional fixation means are required and / or that conventional devices for laying out mulching films cannot be used.

[0007] An object of the present invention can therefore be seen in overcoming this conflict of interests between plastics-based and paper-based mulching films. A particular object can be seen in providing a mulching film, which allows for reduced environmental impact. A further object can be seen in providing an environmentally friendly mulching film, which can be laid out using conventional devices and / or which can be partially covered by soil material without exhibiting problems due to degradation of the material.

[0008] The present inventors have now surprisingly found that a combination of a base material made of processed cellulose fibers and a reinforcement layer applied to the base layer may solve the above objects, in particular if the reinforcement layer has a certain disintegration time.

[0009] It may specifically be provided that the reinforcement layer is only applied to certain areas of the base material. Those areas may particularly be those parts of the mulching film, which are covered by soil when fixing the film to the ground. In the case of a generally elongate, e.g., strip-shaped, mulching film, the reinforcement layer is therefore particularly provided in the longitudinal edge areas of the film, while it does not cover the central portion of the film.

[0010] Typically, the disintegration time of the reinforcement layer is between 6 months and 18 months. This is a period sufficient to provide usability of the mulching film during a complete growth season. However, the reinforcement layer will degrade after the growth season, such that removal of the mulching film after use is not required. The disintegration time as used herein is typically determined under specific conditions, such as in accordance with DIN EN 13432:2000-12. Those conditions typically approximately reflect the durability of the reinforcement layer when covered by soil.

[0011] The disintegration time of the base material is typically lower than the disintegration time of the reinforcement layer. In areas covered by soil, the base material will therefore degrade quicker than the reinforcement layer. However, this does not limit usability of the mulching film. The reinforcement layer will impart mechanical stability to the mulching film, even after the base material has undergone complete disintegration in those parts of the film, which are provided with the reinforcement layer.

[0012] In contrast, in those areas of the mulching film, which are not covered by soil, the base material will typically degrade slower. Therefore, the base material can usually retain its mechanical integrity over a complete growth season, if not covered by soil.

[0013] The mulching film may be suitable for a mulching period of at least three months, preferably of at least four, five, or six months. This particularly means that the base material can withstand environmental conditions like rain and wind for such period without undergoing excessive degradation, if it is not covered by soil.

[0014] The reinforcement layer may provided at least in a fixing portion of the mulching film. The fixing portion typically is the part of the mulching film, which is covered by soil material when the mulching film is weighed to the ground. If the mulching film is an elongate material, there may be two fixing portions running in lengthwise direction, or in other words parallel to the longitudinal edges, of the mulching film. The reinforcement layer may then be provided in the form of two separate lanes, each of the lanes being arranged in one of the fixing portions. The two lanes will typically be interspersed by an area of base material, which is not covered by the reinforcement layer. The lanes typically have a greater width than the fixing portions.

[0015] The width of one lane may be less than 30%, in particular less than 25%, of the width of the mulching film. The width of one lane may be more than 5%, in particular more than 10%, of the width of the mulching film.

[0016] Generally, the areas of the base material covered by the reinforcement layer should extend beyond the fixing portion(s) of the mulching film. In other words, a connection portion may be provided, which is not intended to be covered by soil material, but which is provided with the reinforcement layer. Thus, despite degradation of the base material due coverage with soil material, a link between the reinforcement layer and the base material will be retained.

[0017] Typically, it is provided that in all areas of the film, which comprise the reinforcement layer, also base material is provided. This way, a multi-layer structure with at least two layers may be formed. However, embodiments where areas of the film are only provided with the reinforcement layer, i.e., as a single-layer structure, are also disclosed. For example, the fixing portion may partially or completely comprise the reinforcement layer without base material. In specific embodiments, it may be provided that an overlap between base material and reinforcement layer is only present in a connection portion or in connection portions.

[0018] In a specific embodiment, wherein the mulching film has an elongate shape, two fixing portions may run in lengthwise direction of the mulching film. The fixing portions may extend from the edges or from near the edges of the mulching film towards the center of the mulching film. The fixing portions are typically intended by be covered by soil material. The fixing portions may be neighbored by connection portions, which also run in lengthwise direction of the mulching film and in particular parallel to the fixing portions. The connection portions may also be provided with the reinforcement layer. Additionally, a central portion may be provided between the connection portions, where no reinforcement layer is provided. Typically, neither the connection portions nor the central portion is intended to be covered by soil material.

[0019] The mulching film may have a length of at least 5 m, but the length may also be at least 100 m, or at least 500 m.

[0020] The reinforcement layer may beneficially be made of or comprise a natural material, such as natural fibers. In a specific embodiment, the reinforcement layer may be a net material and / or a net fabric. The net may be formed of yam from natural fibers, such as flax fibers.

[0021] The connection between the reinforcement layer and the base material may be established by any suitable adhesive, in particular by an adhesive, which is essentially insoluble in water.

[0022] The mulching film of the invention may be plastics-free. The term “plastics-free” particularly describes the fact that the mulching film does not contain synthetic or semisynthetic polymers. Materials that contain traces of plastics are covered by the term “plastics-free”.

[0023] The mulching film may be composed of only two layers, namely the base material and the reinforcement layer. A “layer” particularly relates to a part of the film having substantially uniform composition at least in the thickness direction of the film. The term “thickness direction” may refer to an orientation that runs transverse to the main plane of extension of the film.

[0024] The base material may be paper, in particular Kraft paper. The base material may be microcrepped paper or microcrepped Kraft paper.

[0025] Further optional features of the base material are described below. These may lead to improved function of the mulching film, as they may impart the base material with beneficial characteristics, especially in areas of the film, which are not covered by the reinforcement layer. One or a selection of two or more of these features may be provided in the base material.

[0026] The base material may have a tensile energy absorption (TEA) in machine direction (MD) of at least 100 J / m2, in particular of between 250 J / m2and 400 J / m2The tensile energy absorption of the mulching film may particularly be determined in accordance with ISO 1924-3:2005. The tensile energy absorption (TEA) in cross direction (CD) of the mulching film may bet at least 100 J / m2.

[0027] The tensile strength of the base material in the machine direction may range between 6.5 and 9.0 kN / m and / or the tensile strength of the base material in the transverse direction may range between 4.5 and 7.0 kN / m. The tensile strength may particularly be determined in accordance with ISO 1924-3:2005.

[0028] The stretch at break of the base material in the machine direction may range between 6.0 and 11 % and / or the stretch at break of the base material in the transverse direction may range between 6.0 to 12 %. The stretch at break may particularly be determined in accordance with ISO 1924-3:2005.

[0029] The wet tensile strength of the base material in the machine direction may range between 1.6 and 2.7 kN / m. The wet tensile strength may particularly be determined in accordance with ISO 3781 :2011 .

[0030] The tear strength of the base material in both machine and transverse direction may range between 800 and 1700 mN. The tear strength may particularly be determined in accordance with ISO 1974:2012.

[0031] The base material may contain a wet strength agent in the range of between 1.5 and 6.5 kg / t paper atro. The wet strength agent may particularly be or comprise polyamidoamine-epichlorohydrine (PAAE). Moreover, it can be envisaged that the base material comprises between 2.0 and 4.0 kg / t paper atro of starch and / or a starch derivative, preferably cationic starch. The base material may contain a sizing agent in a content of between 0.5 and 2.0 kg / t paper atro.

[0032] The base material may have a basis weight of between 50 and 150 g / m2in accordance with ISO 536:2019.

[0033] The base material may have a tensile energy absorption index in machine direction of between 3.0 and 5.0 J / g. The base material may have a tensile energy absorption index in transverse direction of between 3.0 and 5.0 J / g. The tensile energy absorption index may be determined in accordance with ISO 1924-3:2005.

[0034] The base material may have a tensile energy absorption ratio MD / CD of between 1 .0 and 2.0.

[0035] The base material may have a tensile index in machine direction of between 70 and 120 kNm / kg. The base material may have a tensile index in transverse direction of between 40 and 90 kNm / kg. The tensile index may be determined in accordance with ISO 1924- 3:2005.

[0036] The base material may have a tear index in machine direction of between 8.0 and 12.0 Nm2 / kg. The mulching film may have a tear index in transverse direction of between 12.0 and 18.0 Nm2 / kg. The tear index may be determined in accordance with ISO 1974:2012.

[0037] The base material may have a Gurley value of between 3 s and 50 s. The Gurley value may be determined in accordance with ISO 5636-5:2013.

[0038] The base material may have a Cobb 60s value on the wire side of between 15 and 35 g / m2. The base material may have a Cobb 60s value on the upper side of between 15 and 35 g / m2. The base material may have an average Cobb 60s value of between 15 and 35 g / m2.

[0039] The base material may have a Cobb 60s value of at most 35 g / m2. The base material may have a Cobb 1800s value of at most 70 g / m2. The base material may have a Cobb 1800s value of between 20 g / m2and 70 g / m2. The base material may have an average Cobb 1800s value of between 20 g / m2and 70 g / m2.

[0040] The Cobb value may be determined in accordance with ISO 535:2014.

[0041] The base material may have a formation of between 60 and 90.

[0042] The base material may have a wet tensile index in machine direction of between 15 and 35 kNm / kg. The wet tensile index may be determined in accordance with ISO 3781 :2011.

[0043] The base material may have a burst index on the wire side of between 6.0 and 9.0 mN / kg. The base material may have a burst index on the upper side of between 6.0 and 9.0 mN / kg. The mulching film may have an average burst index of between 6.0 and 9.0 mN / kg. The burst index may be determined in accordance with ISO 2758:2014.

[0044] The base material may have a thickness of between 100 and 150 pm. The thickness may be determined in accordance with ISO 534:2011 .

[0045] The base material may have a bending stiffness in machine direction of between 60 and 100 mN. The base material may have a bending stiffness in transverse direction of between 50 and 90 mN. The bending stiffness may be determined in accordance with ISO 2493-1 :2010. The bending stiffness may be determined at a bending length of 10 mm and at a bending angle of 15°.

[0046] The base material may have a Bendtsen roughness on the wire side of between 700 and 1200 ml / min. The base material may have a Bendtsen roughness on the upper side of between 1200 and 1700 ml / min. The Bendtsen roughness may be determined in accordance with ISO 8791 -2:2013.

[0047] The base material may have a static friction coefficient on the wire side of between 0.3 and 0.7. The mulching film may have a static friction coefficient on the upper side of between 0.3 and 0.7. The static friction coefficient may be determined in accordance with ISO 15359:1999.

[0048] The base material may have a density of between 500 and 1000 kg / m3.

[0049] The base material may have a dynamic friction coefficient on the wire side of between 0.3 and 0.7. The base material may have a dynamic friction coefficient on the upper side of between 0.3 and 0.7. The dynamic friction coefficient may be determined in accordance with ISO 15359:1999.

[0050] The present description further relates to an arrangement of a mulching film on a soil surface.

[0051] In such arrangement, the fixing portion of the mulching film may be covered with soil material. A connection portion of the mulching film, neighboring the fixing portion, may not be covered with soil material, while the connection portion is still provided with the reinforcement layer. A further portion of the mulching film, in particular a central portion thereof, may not be covered by soil material. In the arrangement, plants may be provided in the further portion, in particular the central portion, of the mulching film.

[0052] The mulching film may be provided with two separate lanes of reinforcement layer, each lane being located in the area of a longitudinal edge of the film.

[0053] The width of the fixing portion, i.e., the width of the area of the mulching film covered by soil material, may be less than the width of the lane. In other words, the lanes or the area of the mulching film where the lanes are located, may be partially covered with soil material, such that a connection portion is provided, which is not covered by soil material.

[0054] A mulching film comprising a base material is described, wherein the base material is made of mechanically and / or chemically processed cellulose fibers derived from wood, rags, grasses or other vegetable sources. It may be provided that the mulching film is partially provided with a reinforcement layer, which reinforcement layer has a disintegration time determined in accordance with DIN EN 13432:2000-12 of between 6 months and 18 months, in particular of between 9 months to 15 months.

[0055] It may be provided that the reinforcement layer is provided in a fixing portion of the mulching film.

[0056] It may be provided that the disintegration time of the reinforcement layer is longer than the disintegration time of the base material, wherein the disintegration time of the base material preferably is below 3 months determined in accordance with DIN EN 13432:2000-12.

[0057] It may be provided that the reinforcement layer is provided as two separate lanes, which lanes run in the longitudinal direction of extension of the mulching film.

[0058] It may be provided that each lane has a width of between 20 cm and 50 cm, which width extends from a longitudinal edge of the base material to the center of the base material.

[0059] It may be provided that each lane has a width of between 10% and 25% of the width of the mulching film, which width extends from a longitudinal edge of the base material towards the center of the base material.

[0060] It may be provided that a central portion of the base material is uncovered by the reinforcement layer, which central portion lies between the two lanes.

[0061] It may be provided that the reinforcement layer is a net material with a mesh size of up to 30 mm.

[0062] It may be provided that the reinforcement layer comprises or is made of natural fibers, such as flax fibers.

[0063] It may be provided that the mulching film has a width of between 60 cm and 240 cm. It may be provided that the base material is uncoated and / or in that the base material is paper, in particular Kraft paper.

[0064] A use of a mulching film for covering a soil surface, in particular in an area of interest for agriculture, horticulture, and / or forestry, is also disclosed.

[0065] Further disclosed is an arrangement of a mulching film on a soil surface, wherein the mulching film is attached to the soil surface by soil partially covering the upper surface of the mulching film.

[0066] It may be provided that the mulching film is covered with soil exclusively in at least one fixing portion of the mulching film, which is provided with the reinforcement layer.

[0067] It may be provided that the mulching film is provided with a connection portion, which connection portion is not covered with soil, and which connection portion is arranged adjacent to the fixing portion.

[0068] It may be provided that the mulching film is provided with planting holes, which planting holes preferably arranged in an area of the mulching film, which is not provided with a reinforcement layer.

[0069] Further features can be derived from the patent claims, the drawings and the description of the exemplary embodiment. In the following, the items disclosed herein will be described in detail by making reference to a specific embodiment of the mulching film. This description is not intended to limit the scope of protection of the patent claims.

[0070] In the drawings:

[0071] Fig. 1 shows a schematic perspective view of a soil area covered with a mulching film;

[0072] Fig. 2 shows a schematic side view of a mulching film; and

[0073] Fig. 3 shows a schematic top view of the mulching film of Fig. 2.

[0074] Except indicated otherwise, the drawings show the following features: Base material 1 ; mulching film 2; reinforcement layer 3; fixing portion 4; lane 5; longitudinal direction of extension 6 (of the mulching film 2); width 7 (of a lane 5); longitudinal edge 8; center 9; central portion 10 (of the base material 1 ); width 11 (of the mulching film 2); soil surface 12; soil 13; connection portion 14; planting hole 15; ridge 16.

[0075] Fig. 1 shows a schematic perspective view of an arrangement of a mulching film 2 on a soil area. The soil surface 12 has an undulated structure, which is covered by the mulching film 2. At the peak of the undulated structure, planting holes 15 are provided in the mulching film 2, through which the surface parts of plants can penetrate, which are planted in this area.

[0076] The longitudinal direction of extension 6 of the mulching film 2 runs essentially parallel to the peak of the undulated structure on the soil surface 12. It covers a length of more than 50 m.

[0077] The mulching film 2 is fixed using two ridges 16 of soil 13, which ridges 16 cover the mulching film 2 from above in fixing portions 4. In other words, the soil 13 weighs the mulching film 2 to the ground. The fixing portions 4 run in the longitudinal direction of extension 6 of the mulching film 2 and extend from the longitudinal edges 8 of the mulching film 2 towards its center 9. The fixing portions 4 are neighbored by connection portions 14. The detailed structure of the mulching film 2 will be described below by making reference to Figs. 2 and 3.

[0078] The arrangement shown in Fig. 1 can be obtained by conventional devices for laying out common mulching films made from plastics.

[0079] Detailed views of the mulching film 2 are shown in Figs. 2 and 3, wherein Fig. 2 shows a sectional side view and Fig. 3 shows a top view of the mulching film 2. It should be noted that the drawings are not to scale.

[0080] The mulching film 2 has a two-layer structure, formed by a base material 1 and two lanes 5 of a reinforcement layer 3. The lanes 5 have a width 7, which extends from one longitudinal edge 8 of the base material 1 to the center 9 of the base material 1 . Between the two lanes 5, a central portion 10 is provided, where no reinforcement layer 3 is arranged.

[0081] Each lane 5 of the reinforcement layer 3 provides a fixing portion 4 and a connection portion 14, wherein the fixing portion 4 is intended to be covered by soil 13, and wherein the connection portion 14 is not intended to be covered by soil 13, as depicted in Fig. 1 . This way, degradation of the base material 1 when covered by soil will not have a negative influence on the fixation of the mulching film 2, as in the connection portion 14, the base material 1 will still be intact.

[0082] Between the two lanes 5, a central portion 10 is provided, which is arranged around the center 9 of the mulching film 2. In the central portion 10, the mulching film 2 is only formed by the base material 1 , without being covered by the reinforcement layer 3.

[0083] In this exemplary embodiment, the mulching film 1 has a width 11 of approximately 130 cm, and each of the lanes 5 has a width 7 of approximately 30 cm. In the arrangement of Fig. 1 , the fixing portions 4 each have a width of approximately 25 cm.

[0084] The base material 1 of the mulching film 2 according to this embodiment is Kraft paper. The profile of characteristics of the Kraft paper is shown in Table 1 below.

[0085] Table 1: Parameters of the base material of the exemplary mulching film

[0086] The base material 1 has a disintegration time determined in accordance with DIN EN 13432:2000-12 of approximately two months. Therefore, it will degrade quickly when covered by soil 13 and it will not be usable during a whole cultivation period of typical crops. However, when not covered by soil 13, i.e., in the connection portions 14 and in the central portion 10, the base material 1 will be widely resistant to environmental impact, such as wind and rain, and it will retain its integrity over a cultivation period of several months.

[0087] The reinforcement layer 3 of this exemplary embodiment is formed from a net fabric composed of yam from linen fibers with a mesh size of approximately 10 x 10 mm. The reinforcement layer 3 is connected to the base material 1 using water-insoluble adhesive. The disintegration time of the net fabric determined in accordance with DIN EN 13432:2000-12 is approximately ten months. Therefore, the reinforcement layer 3 will only slowly degrade when covered by soil 13 and it will last for a whole cultivation period of typical crops.

[0088] Due to the short disintegration time of the base material 1 , the area of base material 1 , which is arranged in the fixing portions 4 will quickly lose its integrity, such that only the reinforcement layer 3 will remain. In the connection portions 14, the base material 1 will degrade slowly and therefore the connection between the base material 1 and the reinforcement layer 3 will be retained. Thus, the central portion 10 of the base material 1 will be held on the soil surface 12 by means of the remaining reinforcement layer 3, which is covered by the ridge 16 of soil.

[0089] When the crops have been harvested, the mulching film 2 can be worked into the soil and allowed to disintegrate until the next crops are planted. This way, no removal and disposal of the mulching film 2 is required.

Claims

Claims1. A mulching film comprising a base material (1 ), wherein the base material (1 ) is made of mechanically and / or chemically processed cellulose fibers derived from wood, rags, grasses or other vegetable sources, characterized in that the mulching film (2) is partially provided with a reinforcement layer (3), which reinforcement layer (3) has a disintegration time determined in accordance with DIN EN 13432:2000-12 of between 6 months and 18 months, in particular of between 9 months to 15 months.

2. Mulching film according to claim 1 , characterized in that the reinforcement layer (3) is provided in a fixing portion (4) of the mulching film.

3. Mulching film according to claim 1 or 2, characterized in that the disintegration time of the reinforcement layer (3) is longer than the disintegration time of the base material (1 ), wherein the disintegration time of the base material (1 ) preferably is below 3 months determined in accordance with DIN EN 13432:2000-12.

4. Mulching film according to any of claims 1 to 3, characterized in that the reinforcement layer (3) is provided as two separate lanes (5), which lanes (5) run in the longitudinal direction of extension (6) of the mulching film (2).

5. Mulching film according to claim 4, characterized- in that each lane (5) has a width (7) of between 20 cm and 50 cm, which width (7) extends from a longitudinal edge (8) of the base material (1 ) to the center (9) of the base material (1 ), and / or- in that each lane (5) has a width (7) of between 10% and 25% of the width of the mulching film (2), which width (7) extends from a longitudinal edge (8) of the base material (1 ) towards the center (9) of the base material (1 ).

6. Mulching film according to claim 4 or 5, characterized in that a central portion (10) of the base material (1 ) is uncovered by the reinforcement layer (3), which central portion (10) lies between the two lanes (5).

7. Mulching film according to any of claims 1 to 6, characterized in that the reinforcement layer (3) is a net material with a mesh size of up to 30 mm.

8. Mulching film according to any of claims 1 to 7, characterized in that the reinforcement layer (3) comprises or is made of natural fibers, such as flax fibers.

9. Mulching film according to any of claims 1 to 8, characterized in that the mulching film (2) has a width (11) of between 60 cm and 240 cm.

10. Mulching film according to any of claims 1 to 9, characterized in that the base material (1 ) is uncoated and / or in that the base material (1 ) is paper, in particular Kraft paper.

11. A use of a mulching film according to any of claims 1 to 10 for covering a soil surface (12), in particular in an area of interest for agriculture, horticulture, and / or forestry.

12. An arrangement of a mulching film (2) according to any of claims 1 to 10 on a soil surface (12), wherein the mulching film (2) is attached to the soil surface (12) by soil (13) partially covering the upper surface of the mulching film (2).

13. Arrangement according to claim 12, characterized in that the mulching film is covered with soil (13) exclusively in at least one fixing portion (4) of the mulching film (2), which is provided with the reinforcement layer (3).

14. Arrangement according to claim 13, characterized in that the mulching film is provided with a connection portion (14), which connection portion (14) is not covered with soil (13), and which connection portion (14) is arranged adjacent to the fixing portion (4).

15. Arrangement according to any of claims 12 to 14, characterized in that the mulching film (3) is provided with planting holes (15), which planting holes (15) preferably arranged in an area of the mulching film (3), which is not provided with a reinforcement layer (3).

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