PAPER BAG AND ITS USE

Description

[0001] The invention relates to a bag for moist and biologically active bulk materials, such as potting soil. Commercially available potting soil typically has a residual moisture content in the range of 20-25% by weight and is a biologically active and organic material, which places special demands on the packaging.

[0002] The packaging of potting soil in plastic bags, especially those made of polyethylene (PE), is already well-known. Due to their plastic composition, such bags are not environmentally friendly, which is becoming increasingly undesirable.

[0003] Paper bags for packaging dry bulk goods are also known. To manufacture such bags, single- or multi-layered paper webs are typically formed into a continuous tube in a so-called tube-forming machine and separated into tube sections of suitable length, from which the bag is then formed, for example, by means of a cross-fold or block-fold bottom. During bag production, the paper is glued at suitable points to fix the bag's shape. However, the paper bags known at this time are unsuitable for packaging moist bulk goods, among other reasons because moisture from the contents penetrates the bag material and the glued joints, impairing the bag's strength and stability.

[0004] Publication CN 108 657 592 A describes a paper packaging bag for UV-curing ink with a UV-light-shielding layer. Publication WO 2015 / 169424 A1 describes a paper bag and an adhesive for its manufacture, the adhesive being a starch-containing aqueous solution with an additional adhesive added.

[0005] Against this background, the object of the present invention is to propose an environmentally friendly paper bag for moist potting soil and similar bulk materials, which ensures a sufficiently stable and easy-to-handle package. In this context, a paper bag for packaging, transporting, and storing bulk materials with a residual moisture content in the range of 20–25% by weight is preferred, in which the properties of the contents are preserved as well as possible and, for example, mold growth or drying out is prevented.

[0006] According to the invention, the problem is solved by a paper bag according to claim 1. Advantageous embodiments are set out in the dependent claims.

[0007] The paper bag according to the invention is formed from a tubular piece comprising at least two layers of paper. Advantageously, the paper bag is made of exactly two or exactly three layers of paper. In the bag according to the invention, the bonding of the bag material typically required in bag production is carried out with a biodegradable adhesive. This makes the bag more environmentally friendly overall. According to the invention, the innermost paper layer of the tubular piece has a water-repellent coating on its outer surface facing away from the inside of the bag. This coating can preferably be a PE coating. At least one paper layer has a darkening, preferably black, coloration on at least its inner surface facing the inside of the bag. In this context, "darkening" refers to any coloration that makes the paper darker compared to its natural color.For example, dark or black ink can be printed on the inside of a paper layer to create a darkening effect. Advantageously, the darkening ink can be applied to the inside of the innermost paper layer, the one in contact with the contents.

[0008] The sack according to the invention provides an environmentally friendly and stable packaging solution for moist bulk goods such as potting soil. In particular, it is possible to keep the plastic content below 5%, so that the sack can be declared as a pure paper sack according to the relevant regulations. The dark or black printing on the inside of a paper layer prevents or significantly reduces biological activity in the contents. This dark or black printing prevents light from penetrating the interior of the sack. As a result, biological activity in the contents, which is stimulated by light, is reduced. The effect is similar to covering biological material stored outdoors with black silage film. This also reduces the biological activity of the covered material.Applying the water-repellent coating to the outside of the innermost paper layer eliminates the need for a similar coating on the inside. This allows the inner layer to be bonded with conventional biodegradable adhesive. Otherwise, a potentially non-biodegradable specialty adhesive would be required. The water-repellent coating on the outside of the innermost paper layer prevents significant moisture from penetrating from the inside into the outer paper layers. This keeps the outer paper layers dry, ensuring the bag's strength and stability. Thus, the uncoated inner surface of the innermost layer allows for good bag sealing, while the coating on the outside prevents moisture from penetrating the outer layers.Furthermore, the water-repellent coating prevents water from penetrating the bag's interior and the contents. This prevents the contents from becoming more saturated than when filled. Overall, this prevents both drying out and excessive saturation of the contents. The result is a stable and environmentally friendly paper bag for packaging, storing, and transporting potting soil and similarly moist bulk materials, maintaining a stable residual moisture level over typical periods and preventing other adverse changes to the contents.

[0009] The bag according to the invention has a cross or block bottom at one end of the hose section.

[0010] Advantageously, an inner gusset is inserted into the bottom of the bag, which is typically located at the bottom when carried, to reinforce it. It is particularly advantageous with a cross-shaped or block bottom if the inner gusset is glued into the open bottom fold as a sheet-like layer of material. Preferably, the inner gusset is also made of paper to achieve a high level of environmental friendliness. Furthermore, it is preferred according to the invention that the inner gusset is provided with a water-repellent coating, preferably a PE coating, on its outer surface facing away from the inside of the bag. This prevents material layers located outside the inner gusset from becoming damp from the inside, even in the bottom area. A water-repellent coating can be omitted on the inner surface of the inner gusset facing the inside of the bag, thus allowing for good bonding with biodegradable adhesive.In particular, this method allows the inner flap to be glued over a larger area, with its side lacking a water-repellent coating, to the inner surface of the innermost paper layer, which also lacks a water-repellent coating. This results in a particularly strong bottom seal that meets the stability requirements of the moist and heavy contents. It is further preferred that the inner flap has a darkening, preferably black, color on its inner surface facing the inside of the bag to better prevent light penetration at the bottom. The darkening color can be achieved by printing with dark or black ink.

[0011] Advantageously, the biodegradable adhesive contains starch glue, preferably potato starch glue. Starch glue, especially potato starch glue, is a relatively inexpensive adhesive that ensures good adhesion to paper. In a particularly preferred embodiment, the biodegradable adhesive consists entirely of pure starch glue. In another preferred embodiment, a moisture-stable bonding additive, preferably a dispersion adhesive, is added to the biodegradable adhesive. Starch glue has the disadvantage that it dissolves to a certain extent when exposed to moisture or water, thus reducing the strength of the bond. This can be counteracted by adding a moisture-stable bonding additive. A moisture-stable bonding additive is understood to be an additive whose adhesive effect is not affected by moisture or is only minimally affected.Such a moisture-resistant adhesive additive can, for example, be added to a starch-based dispersion adhesive. It is particularly advantageous when the moisture-resistant additive is added to the biodegradable adhesive at a rate of no more than 10%, and preferably no more than 7%. With such a proportion, the amount of non-biodegradable adhesive can be kept low. Furthermore, such an addition is sufficient to maintain good adhesion even if the bond becomes damp.

[0012] In another advantageous embodiment, the adhesive areas of the bag material do not have any coatings that reduce adhesive adhesion. Typically, for example, water-repellent coatings lead to a reduced adhesive effect of starch glue. Therefore, in a preferred embodiment, the adhesive areas of the bag material are not provided with such coatings that reduce adhesive adhesion. The absence of adhesive areas allows the remaining areas of the affected surfaces to be provided with a water-repellent and / or other type of coating, e.g., the inside of the innermost layer of material.

[0013] In another embodiment, adhesive areas of the bag material that are coated with a substance that reduces adhesive adhesion are bonded with a water-resistant adhesive component. Water-resistant adhesives typically achieve good adhesion even on water-repellent coated surfaces. Therefore, it is particularly advantageous to use such adhesive components in water-repellent coated areas.

[0014] In another preferred embodiment, the inside of the innermost paper layer and / or the inside of the inner flap is treated with a fungicide. This prevents mold growth in the bag material and the contents.

[0015] This is advantageously a natural fungicide. Applying an antimicrobial substance is also beneficial.

[0016] In another preferred embodiment, the inside of the innermost paper layer and / or the inside of the inner strip is provided with an alkaline coating. Potting soil is often acidic, i.e., has a pH value below 7. The acid contained in potting soil can attack or decompose the sack paper. According to the invention, this can be counteracted by an alkaline coating on the inside of the innermost paper layer. The alkaline coating can be applied, for example, by brushing. An alkaline coating with chalk or lime is also possible, e.g., by printing an aqueous chalk solution onto the inside of the innermost paper layer. Particularly preferably, the inside of the innermost paper layer is provided with a darkening color, treated with a preferably natural fungicide, and coated with an antimicrobial and alkaline finish.Alternatively, the darkening color can also be applied to the inside of a more outer layer of material.

[0017] In another preferred embodiment, water-repellent paper coatings are designed as plastic-free coatings. Oils or fats, for example, are suitable as such plastic-free coatings. With such plastic-free water-repellent coatings, greater environmental friendliness of the bags according to the invention can be achieved. Advantageously, the water-repellent paper coatings can also be biodegradable, compostable, and / or recyclable.

[0018] It is particularly preferred that the bag according to the invention, in addition to the layers of paper, does not contain any layers of material made of any other material. The bag according to the invention is particularly preferably designed as a two-layer bag made of two layers of paper or as a three-layer bag made of three layers of paper. The two-layer bag provides a material-saving, environmentally friendly paper bag, while the three-layer paper bag offers greater strength and stability.

[0019] In another preferred embodiment, all material layers of the bag are made of paper or similarly biodegradable materials.

[0020] Advantageously, the bag according to the invention is fully compostable and / or recyclable. Such a bag can, for example, be disposed of by the consumer directly in an environmentally friendly manner on their own home compost heap.

[0021] In a further preferred embodiment, the sack according to the invention is designed as a three-layer paper sack, wherein the outermost and innermost layers of material are provided with a water-repellent coating on their outer surface. The middle layer of such a sack can be made of particularly strong kraft paper. In such a sack construction, the strength and stability of the sack are primarily provided by the middle layer of material, while the coatings on the innermost and outermost layers of material ensure that the middle layer does not become damp or soaked through from the outside or inside and thus lose stability. Advantageously, the darkening color can be applied to the inside of the middle layer.

[0022] The sack according to the invention can be designed as a sack with only one bottom, which is open at the top and is filled through this opening. After filling, the opening can be closed, for example, by sewing or gluing.

[0023] In another preferred embodiment, in addition to the existing bottom, a further bottom can be formed at the other end of the hose section, so that the bag has two opposing bottoms. Advantageously, a valve for filling the bag can be inserted into one of the bottoms. An internal locking mechanism can also be inserted into the other bottom.

[0024] The invention also includes the use of a paper bag for packaging potting soil or similarly moist bulk materials. According to a widely held view in the field, moist bulk materials cannot be packaged in paper bags because the moisture of the contents soaks through the paper bags, thus preventing sufficient stability. Within the scope of the invention, it has been found that, contrary to this widely held view, it is nevertheless possible to reliably package moist bulk materials such as potting soil in paper bags. According to the invention, the invention includes the use of a paper bag according to any one of claims 1 to 11 for packaging potting soil or similarly moist bulk materials.

[0025] Exemplary embodiments of the invention are explained in more detail with reference to the following figures. These show: Fig. 1: The basic structure of a two-layer hose section for the production of a bag according to the invention. Fig. 2:A two-layer tube piece for the production of a bag according to the invention. Fig. 3: The open cross bottom of a bag according to the invention with an inserted inner bar. Fig. 4: An inner bolt with adhesive contour Fig. 5: A two-layered bag open at the top according to the invention Fig. 6: A two-layer bag according to the invention with two opposing bottoms, the upper one of which is designed as a valve bottom. Fig. 7: A three-layer tube section for the production of a bag according to the invention. Fig. 8: A three-layer bag open at the top according to the invention

[0026] Figure 1 shows the basic structure of a two-layer hose section 15 for the production of the in Figure 5 and 6 shown bags according to the invention 10. The in Figure 1The shown tube section 15 is formed from an inner layer 20 and an outer layer 30 made of paper, the inner layer 20 having an outer surface 22 facing away from the inside of the bag and an inner surface 24 facing the inside of the bag. The outer layer 30 has an outer surface 32 facing away from the inside of the bag and an inner surface 34 facing the inside of the bag. As shown in Figure 2 As illustrated, in this embodiment the outer surface 22 of the inner layer 20 is fully covered with a water-repellent PE coating, which is in Figure 2 is shown with lined hatching. The inner surface 24 of the inner layer 20 is coated with an alkaline substance and a fungicide, as shown in Figure 2 depicted with diagonally crossed hatching. The inner side 34 of the outer layer 30 is printed with black ink, as shown in Figure 2depicted with vertically and horizontally crossed hatching. In an alternative embodiment, the alkaline coating on the inner side 24 of inner layer 20 can be omitted. In this embodiment, the inner side 24 of inner layer 20 can be printed with black ink, either additionally or instead of the inner side 34 of outer layer 30.

[0027] Figure 3 Figure 1 shows the open cross bottom 40 of a bag according to the invention, into which an inner bar 50 is inserted. The inner side 54 of the inner bar 50, which rests on the open cross bottom 40 and faces the interior of the bag, is in Figure 4Illustrated. On the diagonally cross-hatched inner surface 54, the inner flap is provided with an alkaline coating and additionally with a fungicide to prevent acid corrosion and mold growth in the contents and the bag material. Furthermore, the inner surface 54 is provided with a frame-shaped adhesive contour 56 to glue the inner flap 50 into the open cross bottom 40 of the bag 10 according to the invention. On the outer surface 52 facing away from the inside of the bag, the inner flap 50 is provided with a water-repellent coating, which is Fig. 3 is depicted in diagonally lined hatching.

[0028] Figure 5Figure 1 shows a two-layer bag 10 according to the invention with a closed cross bottom 40 as a base. The bag is open at the top 41 opposite the bottom for filling. After the bag 10 is filled with potting soil, the open top 41 can be closed by sewing. The inner layer 20 of the paper bag 10 is provided with an alkaline coating and a fungicide on its inner surface 24 and with a water-repellent PE coating on its outer surface 22. The inner layer 20 and the outer layer 30 are made of paper. The outer layer 30 is printed black on its inner surface 34. The outer surface 32 of the outer layer 30 can also be printed and / or coated, e.g., with a PE coating.

[0029] Figure 6 shows a variant of a bag 10 according to the invention, in which a cross bottom is also formed on the upper side 41 opposite the base 40, into which a valve 42 is inserted for filling the bag.

[0030] Figure 7 shows a three-layer tube section 15 for the production of a three-layer bag 10 according to the invention, which is in Figure 8 This is illustrated in more detail below. The inner layer 20 has an alkaline coating and a fungicide on its inner surface 24. Furthermore, the inner layer 20 and the outer layer 30 each have a water-repellent PE coating on their outer surfaces 22 and 32, respectively. Between the inner layer 20 and the outer layer 30 of the bag is the intermediate layer 25, which consists of paper printed in black on its inner surface 27. This additional layer of material, compared to a two-layer bag, increases the bag's stability and strength. In an alternative design, the alkaline coating on the inner surface 24 of the inner layer 20 can be omitted.

[0031] The paper bag according to the invention allows moist potting soil to be packaged in an environmentally friendly and easy-to-handle manner, while maintaining the product properties of the potting soil for relevant periods of several weeks to months. In particular, the black printing on the inside reduces light-induced biological activity in the potting soil. The fungicide applied to the inside prevents mold growth in the potting soil and also in the bag material. The water-repellent PE coating on the outside of the inner layer prevents the potting soil from drying out and also prevents the penetration of additional moisture from the outside, which would make the potting soil heavier. By preventing water from escaping the potting soil, the outer layer of the bag material can also be kept dry and stable.

Claims

1. A paper bag (10) for potting soil or comparable moist bulk materials, formed from a tubular piece (15) comprising at least two paper layers (20, 25, 30), wherein at one end of the tubular piece the bag (10) has a cross bottom or block bottom (40), wherein the bonds of the bag (10) are formed with biodegradable adhesive, characterized in that the innermost paper layer (20) of the tubular piece (15) has a water-repellent coating, preferably a PE coating, on its outer face (22), and at least one of the paper layers (20, 25, 30) has a darkening, preferably black colouring at least one its inner face (24, 27, 34).

2. The paper bag according to the foregoing claim, characterized in that an inner lining (50) preferably formed of paper is inserted into the bottom (40), wherein the inner lining (50) is provided with a water-repellent coating, preferably a PE coating, on the outer face (52) facing away from the interior of the bag and / or the inner lining has a darkening, preferably black colouring at least on its inner face (54) facing the interior of the bag.

3. The paper bag according to one of the foregoing claims, characterized in that the biodegradable adhesive contains starch glue, preferably potato starch glue, and / or a moisture-stable bonding additive, preferably dispersion glue, is admixed to the biodegradable adhesive.

4. The paper bag according to the foregoing claim, characterized in that the moisture-stable bonding additive is admixed to the biodegradable adhesive with a content of not more than 10% by weight, preferably not more than 7% by weight.

5. The paper bag according to one of the foregoing claims, characterized in that the bonding regions of the bag material have no coatings reducing the adhesion and / or are bonded with a water-resistant adhesive component.

6. The paper bag according to one of the foregoing claims, characterized in that the inner face (24) of the innermost paper layer (20) and / or the inner face (54) of the inner lining (50) in contact with the filling material are treated with a preferably natural fungicide and / or an antimicrobially acting substance and / or are provided with an alkaline application.

7. The paper bag according to one of the foregoing claims, characterized in that the water-repellent paper coatings are implemented as free of plastic, biodegradable, compostable and / or recyclable coatings.

8. The paper bag according to one of the foregoing claims, characterized in that all material layers (20, 25, 30) of the bag consist of paper and / or comparable biodegradable materials.

9. The paper bag according to one of the foregoing claims, characterized in that the bag is fully compostable and / or recyclable.

10. The paper bag according to one of the foregoing claims, characterized in that the bag is formed as a three-layer paper bag, wherein the outermost material layer (30) is preferably provided on its outer face with a water-repellent, biodegradable, compostable and / or recyclable coating.

11. The paper bag according to one of the foregoing claims, characterized in that the bag is closed at one end of the tubular piece by suture or a bottom is formed at both ends of the tubular piece, preferably a cross bottom or block bottom, wherein preferably a valve is inserted in one bottom for filling the bag.

12. Use of a paper bag according to one of claims 1 - 11 for packaging potting soil or similar moist bulk materials.