ES2618327T3 - Bag to collect organic waste or food - Google Patents

Abstract

A bag (1) for collecting organic compostable waste of the type with a lower base (4) and side walls (AF), which can be mounted from a preform (2) of paper material, folded and glued, said preform having a lower line (7), intended to form the lower base (4) of said bag (1), which comprises in its interior a lower flap (3) that can be moved between a non-operative position, in which said lower flap ( 3) is located substantially parallel to said side walls (AF), and an operative position, in which said lower flap (3) is substantially parallel to said lower base (4), when said bag is in an upright configuration, characterized because said bottom flap (3) is made of an absorbent and compostable material, and because said bottom line (7) of the preform (2) has a number of stages, so that the bottom base (4) of said bag (1) ) is of the "flat bottom" type in which dic It has bottom flap and the bag itself are biodegradable and compostable.

Description

DESCRIPTION

Bag to collect organic waste or food

Field of the Invention

The present invention is about a bag for collecting organic waste or food, in particular it is about a highly biodegradable bag for collecting compostable waste. 5

Background of the invention

In many countries, the rules on waste collection and disposal allow the organic portion to be isolated so that it is subjected to additional disposal procedures that reduce its impact on the environment or make it possible to recycle it or use it in different technical fields . For example, the organic fraction of urban waste collected separately or organic waste from agricultural and industrial activities 10 is subjected to a procedure called "composting." Composting can be defined as the procedure by which natural decomposition is controlled, accelerated and optimized, to which any organic substance is subjected by the effect of the microbial flora normally present in the environment. In other words, composting is an aerobic process of a biological decomposition of organic substances that takes place under controlled conditions and allows a biologically stable product called "compost" to be obtained. The compost obtained from urban organic waste collected (or preselected) separately contains an amount of humus, microbial flora and fertilizer elements, such as to allow its use for agricultural purposes, for example as fertilizer in nurseries or for crops in general. Compost can also be obtained from wastes that are not collected (or not preselected) separately, created properly, to be used in sectors other than agriculture, for example as filler material for environmental recovery, or to cover Daily landfills.

To obtain a high quality compost (stable and that has good fertilizer characteristics), it is necessary that the bag or the bag used to collect organic waste is also biodegradable, and to favor the natural process of decomposition of the waste.

Among the containers traditionally used for waste collection are bags made of 25 plastic polymers. One of the most used materials for this purpose is polyethylene. Disadvantageously, although resistant, elastic bags are not biodegradable and their removal is difficult and expensive. In other words, bags of this type are very polluting for the environment. In addition, the bags made of plastic material are not breathable, that is, they are not permeable to air and, thus, hinder the circulation of oxygen to the wastes they contain, which tend to rot quickly, with the consequent formation of unpleasant odors. For these reasons, plastic bags are not suitable for collecting compostable organic waste.

In the field of separate collection of compostable organic waste, bags and bags obtained from biodegradable raw materials, for example corn starch, have recently been provided on the market. Traditional containers of this type are widely used in the home for the collection of organic waste 35, for example kitchen scraps, leaves or other plant material, etc. As a compostable waste, corn starch is subjected to natural decomposition and thus does not pollute the environment. Disadvantageously, the air permeability of this type of bag / bag is low. For this reason, the amount of air that, under normal use of the bag, interacts with the waste it contains is minimal and the waste is often subjected to rapid decomposition (rot) that produces unpleasant odors. This inconvenient aspect 40 also has important implications for the quality of the compost obtained from the collected waste. In fact, too rapid decomposition of the waste in the bag can have a negative influence on the phases of the composting procedure after the collection of the waste, and can lead to the formation of a low quality compost. Another problem associated with the production and use of this type of bag and bag is in the fact that the corn starch polymer (or the biodegradable material used alternatively) is hot extruded, usually with synthetic polymers that increase its mechanical characteristics but that are not biodegradable. In fact, normally the corn starch polymer, as such (i.e. considered itself), does not allow the containers or bags to be manufactured with sufficient strength for use in the collection of organic waste, which may even have a specific weight quite high. Thus, starch usually binds with plastic polymers, for example polyethylene, which have suitable mechanical properties that are not subjected to natural decomposition and which, once released into the environment, are configured as polluting substances. In addition, corn starch is degradable in contact with liquids released by organic waste and, therefore, traditional bags made of this material can be subject to breakage if the waste contains considerable amounts of water (for example, consider fruit). For some time now it has been felt the need to have 55 organic waste containers that are completely biodegradable, very breathable and, at the same time, resistant.

An additional type of containers traditionally used for the collection of organic waste is bags / bags made of paper, for example of the type obtained from a preform folded and glued properly. The

Bags / bags made of paper material are normally available in a folded configuration, that is, they are sold in flat configuration, and the user opens the bag or bag, giving it an upright configuration for use. Advantageously, the bags and bags made of paper material, for example paper or cardboard, have a considerable perspiration capacity and favor the passage of air into the wastes they contain in considerably larger quantities than in the bags made of plastic, or with polymers based on cornstarch. This feature allows the unleashing of a progressive process of oxidation of waste and, therefore, favors the controlled decomposition of waste without rotting in a short time. For these reasons, the final compost obtained when the waste is collected in paper bags is of high quality. In addition, the high air permeability of paper bags minimizes the formation of unpleasant odors, a phenomenon that is easily found in the use of containers made of plastic or 10 polymers based on cornstarch. A non-negligible problem presented by paper bags is their poor mechanical resistance in the presence of liquids. In fact, the liquids released by the waste collected in these bags are quickly absorbed by the paper material, which weakens and tends to collapse. In these cases it is difficult to maintain the integrity of the bags during handling. Paper bags are manufactured, in general, from preforms folded and glued properly. Liquids 15 released by the wastes contained in a paper bag often act as glue solvents; that is, they weaken the point at which the bag is glued, which may fail, with the consequent rupture of the bag.

Paper bags or bags are often used for shopping, that is, to transport fresh food from supermarkets and food stores. Disadvantageously, bags made of paper, cardboard or similar paper material do not guarantee the endurance if the food they contain has a lot of weight. twenty

The German utility model DE 6605916U discloses a bag according to the preamble of claim 1, the bag being used as a shopping paper bag provided with a paper flap intended to cooperate with the bottom base to increase the maximum load that You can hold the bag. The flap is provided on the preform, during the manufacture of the bag. Once the bag is raised, the flap can be rotated from a vertical position to a horizontal configuration. 25

WO 89/10311 discloses a recycled paper bag for collecting wet organic wastes to be treated as compost. The bag is equipped with an internal insert made of an absorbent material, intended to collect the liquids released by the waste. A suitable material is clay, for example bentonite.

The objective of the present invention is to provide a container in the form of a bag or bag for collecting 30 organic wastes, in particular for collecting compostable organic wastes, which overcomes in a simple and efficient manner the disadvantages of traditional bags / bags, which at the same Time is cheap and easy to use.

A further object of the present invention is to provide a bag for collecting organic waste, in particular for collecting compostable organic waste, which is biodegradable, resistant and very permeable to air. 35

A further objective of the present invention is to provide a bag for collecting compostable organic wastes, in particular for the selective collection of said wastes, which favors the correct activation of the respective composting process.

A further objective of the present invention is to provide a bag for the selective collection of compostable organic wastes that is resistant to liquids released by the same wastes. 40

Another objective of the present invention is to provide a bag for the selective collection of compostable organic wastes that minimizes the formation of unpleasant odors due to the decomposition process of the waste it contains.

Summary of the invention

These and other objectives are achieved by the present invention, which relates to a bag for collecting waste or containing food according to claim 1.

The term "bottom flap" is used to identify any element that has a suitable way to overlap, at least in part, with the bottom base, or bottom, of the bag. Preferably, the bottom flap has a flat shape, for example it can be a sheet shaped properly.

Advantageously, the bag according to the present invention is provided, inside, with a bottom flap that can be turned from a non-operative position, in which the bottom flap is substantially vertical and parallel to the side walls of the bag in an upright configuration (open bag), to be taken to an operative position, in which the bottom flap is placed substantially horizontal, parallel to the bottom base of the bag, so as to increase its resistance.

The user can fold down the bottom flap to an operative position, so that it overlaps, at least in part, with the bottom base of the bag itself, forming a type of double bottom for the bag. In this way it is possible to increase the resistance of the base (bottom) of the bag and of the bag in general. In other words, thanks to the presence of the bottom flap at the base of the bag it is possible to increase the weight of the content compared to that normally contemplated for traditional bags / bags. 5

The bottom flap can simply be inserted inside the bag, for example during its production, or it can be placed inside the bag and anchored thereto to prevent it from coming out or prevent unwanted movements inside the bag. Preferably, the bottom flap is inserted into the bag and anchored thereto by means of one or more tail points on a side wall. The fixing is of a separable type, that is, it must be possible to easily separate the bottom flap from the inner surface of the bag to fold it down on the bottom.

The bag according to the present invention is made of paper or cardboard. Preferably, the bag is made of recycled paper, which has, for example, a weight of 80 g / m2.

The bag is made of a material that is at least partially breathable, that is at least partially permeable to air, so as to favor the aeration of the waste collected in the bag or the aeration of the food transported therein. Paper and cardboard can be suitable materials for the purpose. Air permeability allows the activation of the oxidation processes necessary for the waste composting process and helps to slow down the natural fermentation / ripening of fresh foods. Preferably, the bag itself is biodegradable, that is, the paper or cardboard from which the bag is made is very biodegradable. The material of the bag can be chosen so that it is compostable in a normal cycle 20 of composting of collected waste. In other words, the material of the bag is preferably compostable in a time corresponding to the definitive decomposition of the organic waste it contains.

Since the bag is at least partially breathable, any waste it contains is not subject to rapid rotting, such as that produced when bags made of cornstarch or plastic bags are used. On the contrary, the aeration of the wastes activates slower processes of oxidation and decomposition than those provided by the traditional bags mentioned above. Accordingly, the bag according to the present invention makes it possible to minimize the formation of unpleasant odors.

The bottom flap can be made of different materials depending on the final use of the bag.

If the bag is to be used as a shopping bag to transport fresh food, the bottom flap can be made of cardboard, which has, for example, a thickness of 0.5 mm, which is thick enough to support heavy food in cooperation with the bottom base of the bag.

If the bag is intended to collect waste, especially compostable organic waste (normally collected separately from other household waste), the bottom flap is made of absorbent material. For example, the bottom flap is made of paper or cardboard that weighs between 150 and 180 g / m2. Alternatively, the bottom flap can be made of a spongy material. This feature is particularly advantageous, since this type of waste normally releases liquids that would wet the surfaces of the bag, weakening it. In particular, the function of the lower flap is to avoid, or at least limit, the contact between the liquids released by the wastes and the adhesive substance normally used to glue together the preforms with which the paper bags are normally manufactured. Thanks to the absorbent capacity of the bottom flap, the bottom surfaces of the bag and the glue points at the bottom base of the bag, that is to say the glue points used to form the bottom of the bag from a preform, They are protected against the solvent effect of liquids. Compared to traditional paper bags / bags, liquid resistance is maximized. The bottom flap, as it is absorbent, is also biodegradable and compostable. This means that the entire bag can be completely biodegradable. The formation of unpleasant odors is further limited by the fact that the liquids released by the wastes are absorbed, at least partially, by the lower flap.

The bag can be applied in various sectors related to the collection of food and / or waste. Therefore, the bag can be made with variable dimensions, that is to say with suitable capacities for the different uses, for example with capacities between 8 liters and 120 liters.

The bag, according to the present invention, has a number of advantages over traditional bags / bags. In fact, it allows a greater supply of air to the material it contains compared to that supplied by plastic or corn starch bags, with obvious advantages in reducing unpleasant odors. In addition, the bag according to the present invention has a greater resistance than traditional paper bags, both in terms of the weight of the material contained in the bag and the presence of liquids. These characteristics allow the bag according to the invention to be used effectively to contain food and, above all, to collect organic waste. In particular, since the bag and the bottom flap inside can be made of a compostable material, the bag is suitable for the selective collection of urban organic waste, such as those collected at home, in restaurants, in markets , etc.

The bag according to the present invention allows a high quality compost to be obtained. It is a known fact that the best compost of organic vegetable wastes is obtained, which decompose rapidly, giving rise to a humus rich in fertilizing elements. The bag according to the invention is made of paper material, so it is rich in vegetable fibers. In particular, paper or cardboard is rich in lignin. The presence of these vegetable fibers, and in particular of lignin, allows the optimization of the quality of the compost that can be obtained using the bag.

Brief description of the drawings

Additional aspects and advantages of the present invention will be more apparent by means of the following description, provided as an illustrative, but not limiting example, with reference to the accompanying schematic drawings, in which:

- Figure 1 is a perspective view of a bag according to the present invention in a first configuration;

- Figure 1A is a side view of the bag shown in Figure 1;

- Figure 1B is a perspective view of a bag according to the present invention in a second configuration; fifteen

- Figure 2 is a plan view of a first preform for the production of a bag according to the present invention;

- Figure 3 is a plan view of a second preform for the production of a bag according to the present invention;

- Figure 4 is a plan view of a third preform for the production of a bag according to an alternative embodiment, which is not part of the present invention;

 25

- Figure 5 is a plan view of a fourth preform for the production of a bag according to an alternative embodiment, which is not part of the present invention.

Detailed description of the invention

With reference to Figure 1, a bag 1 according to the present invention is illustrated. Bag 1 has a capacity of approximately 8 liters and is intended for separate collection of compostable waste. The bag 1 is 30 of the type with an open mouth and is shaped from a preform (shown in Figure 2). In general, bag 1 may have different capacities; that is, it can be manufactured with capacities of 10 liters, 50 liters, 100 liters, 120 liters, etc., depending on the different uses for which the bag, or bag, is provided. For example, the bag 1 according to the present invention may be manufactured with a capacity of 120 liters to collect waste in supermarkets, in fresh food stores, in animal husbandry centers, in greenhouses, etc. 35

The bag 1 comprises a body 2, composed of a plurality of side walls A-F and a bottom base 4, and a bottom flap 3 housed inside.

The number, dimensions and arrangement of the side walls depend on the type of preform used to make the bag 1. Figure 2 illustrates a possible embodiment of a preform suitable for the purpose, in which the vertical fold lines 5 identify the Side walls AF of the bag 1. Therefore, the bag 1 is obtained from a preform folded properly, folded and glued according to a technique known in the field of the production of bags and bags. The bag 1 is initially formed in a flattened configuration, ie folded, as shown in Figure 1A. The user can open bag 1; that is, put it in an upright configuration for use. The bag 1 shown in Figure 1 is in an open or upright configuration; that is to say, the bag has been given substantially its maximum dimensions by folding it along the vertical fold lines 45 (or pre-folded lines).

The bag 1 is made of paper material, for example cardboard or paper suitable for food. Preferably, the bag 1 is made of recycled paper, with a low heavy metal content, which has a weight between 50 and 100 g / m2. More preferably, the bag 1 is made of recycled paper that has a weight of approximately 80 g / m2 and is biodegradable in a composting cycle. This feature is particularly useful if bag 1 is used to collect compostable waste. In fact, in a single cycle a composting of both the bag 1 and the waste it contains is obtained, with evident positive effects in relation to the care of the environment. A normal composting cycle begins with the natural oxidation of organic waste in bag 1 and ends with the formation of compost, a biologically stable product rich in humus, microbial flora and fertilizer elements. The initial phase of the cycle takes place during the collection of waste by the user, while the subsequent and final phases are carried out at special sites operated by waste disposal companies according to national laws.

In order to favor the exchange of air towards the contents of the bag 1, whether it is waste or fresh food such as, for example, fruit and vegetables, the paper material chosen to make the bag 1 is at least partially air permeable, that is to say, breathable at least in part. This feature allows the activation of the process of oxidation of wastes or the activation of a minimum aeration of food, with obvious advantages in relation to its conservation. Therefore, the bag 1 according to the present invention can be used, advantageously, both for collecting waste and for containing food. On the contrary, traditional plastic bags (polyethylene) and those made of corn starch are not breathable or have low air permeability and, therefore, favor the rotting of waste and the formation of unpleasant odors.

The presence of the bottom flap 3 allows the problems encountered in the use of traditional paper bags to be overcome. The bottom flap 3 is an element that has such a shape that it overlaps, at least in part, 10 with the bottom base 4 of the bag 1 to increase its mechanical strength and protect any glue point of the preform 2 in the base 4 In Figure 1 the preform 3 is a substantially flat element of rectangular shape. The bottom flap 3 is inserted into the folded flattened bag 1. Thus, the bottom flap 3 is initially placed in an intermediate position between the walls A and D of the bag 1, parallel to them, as shown in Figure 1A. fifteen

In general, the bottom flap can simply be inserted into the bag 1, without any particular link with the body 2 of the bag, or it can be fixed to at least part of the inner surface of the bag 1. In Figures 1 and 1A it is possible to see that the bottom flap 3 partially overlaps the wall D. In particular, in the embodiment shown, the bottom flap 3 is fixed permanently to the wall D of the bag 1, especially it is glued to the bottom surface Internal of this wall. In figure 2, the reference number 6 indicates the line along which the flap 3 is glued to the wall D. The union obtained in this way allows the lower flap 3 to be fixed in a stable position, avoiding that moves from one place to another inside the bag 1 or leaves the bag. It is important that the joint between the bottom flap 3 and the inner surface of the bag be easily separated by the user when preparing the bag 1 for use. In fact, the bottom flap 3 has the characteristic that it can be folded down on the bottom 4 of the bag 1 to adopt an "operational" position 25 substantially parallel to the bottom 4 of the open bag 1. In other words, once that the user has opened the bag 1, taking it to the upright configuration shown in figure 1, the bottom flap 3 can be easily rotated in the direction indicated by the arrows R, breaking the glue points, so that it overlaps with the base bottom (bottom) 4. For this reason, the gluing of the bottom flap 3 must be such that it allows a simple separation of the surfaces without risking damage to the bottom flap 3 or the bag 1. 30

It will be apparent to the person skilled in the art that the anchoring of the lower flap 3 to the inner surface of the bag 1 can be carried out in different ways, equivalent to gluing; for example, by sewing or tabs.

Once it has been folded down on the bottom 4 of the open bag 1, the bottom flap 3 is configured as a double bottom for the same bag. Figure 1B shows the bag 1 with the bottom flap 3 folded down to form a double bottom type. 35

It is evident that the lower flap 3 allows to increase the mechanical resistance of the bag 1, avoiding the mentioned limits shown by the paper bags / bags in relation to the weight of the goods they contain. Thus, in general, the bag 1 according to the present invention has the advantage of allowing a heavier load to be contained than is possible with traditional paper bags / bags of the same type.

In general, the bottom flap 3 can be made of different materials, depending on the applications for which the bag is provided. For example, if the bag 1 is used as a shopping bag, the bottom flap 3 can be made of thick cardboard (1 or 2 mm) or plastic. If the bag 1 is used to collect compostable organic waste, the bottom flap 3 is made of a biodegradable material.

In the example shown in Figures 1-2, bag 1 is used to collect compostable organic wastes, such as collected separately in households in the populations where the respective disposal service is provided. For this application, the bottom flap 3 is made of a material that, in addition to increasing the strength of the bottom base 4, is also absorbent. This feature is particularly advantageous because organic waste normally releases liquids that are easily absorbed by bag 1, with its consequent deterioration. The lower flap 3 absorbs at least part of the liquids released by the wastes, thus minimizing absorption by means of the bag 1, with evident positive effects in relation to the resistance and duration of the same bag 1 In other words, being in the operating position shown in Figure 1B (horizontal and at least partially overlapping with the bottom 4), the bottom flap 3 has the dual function of cooperating with the bottom base 4 to support the contents of the bag. 1 and absorb any liquid released inside the bag 1. In this way it is possible to protect the gluing points (indicated schematically with X in Figure 2) used to form the bottom base 4. Normally, in fact, the glues used To make 55 paper bags, they are soluble in the water present in the liquids released by the waste. This problem has greatly limited the dissemination of paper bags in the organic waste collection sector. The absorption of the liquids by the bottom flap 3 also helps to minimize the formation of unpleasant odors for as long as the waste remains inside the bag.

An absorbent and, at the same time, compostable material suitable for manufacturing the bottom flap 3 is paper (or cardboard), for example of the same type mentioned above in relation to the bag 1. In the case of the bottom flap 3, to increase its strength, the weight of the paper may be heavier than that used for bag 1, for example approximately 150-180 g / m2.

Figures 1; 1A, 1 B and 2 show the bag 1 with a flat bottom 4. In other words, the bottom base 4 of the bag 5 shown is of the type known in the art with the name "flat bottom". It will be apparent to the person skilled in the art that the bag 1 can also be made with other types of bottom, depending on the end use of the bag.

Figures 3-5 show schematically different preforms 2 for the production of the bag 1, which differ in the part provided to form the lower base 4. In particular, the preform 2 in Figure 3 is similar to the preform shown in Figure 2, but differs from it in the different conformation of the lower line 7 which has a greater number of "stages". In this way, it is possible to increase the surface area and maximize the resistance of the bottom 4.

Figure 4 shows a portion of a preform 2 for the formation of a bag 1 having a "square bottom". The reference number 8 indicates the fold lines to form the bottom. Figure 5 refers to a portion of a preform 2 to form a bag 1 with a "cross bottom." Also in this case, the number 8 of 15 reference indicates the fold lines for the bottom.

The bag 1 according to the present invention is simple to manufacture, since it can be obtained from the preform 2 according to known techniques, and is economical, since the bottom flap 3 can be made with minimal costs. The problems that can be found using traditional containers are easily overcome. In fact, the bag 1 is air permeable, resistant to the weight of the content, resistant to any liquid released at the bottom 4 and 20 is biodegradable. In the collection of compostable organic waste, the air permeability of the bag 1 allows the activation of normal oxidation processes, minimizing the risks of rapid spoilage of the waste and, therefore, allows the minimization of odor formation unpleasant generated by the rapid decomposition of organic material. Therefore, the compost that can be obtained from the waste collected using bag 1 is a high quality compost. Thanks to the presence of the bottom flap 3, the bag 25 1 offers greater resistance to the weight of the content than that found in traditional paper bags. In addition, the absorbent capacity of the lower flap 3 minimizes the risks of rupture of the bag 1 due to the action of the liquids released by the wastes and, at the same time, reduces the formation of unpleasant odors developed by those liquids.

The paper or cardboard used to form the bag 1 contains lignin, a natural fiber that is particularly effective for obtaining a high quality compost.

The bag 1 can be made of highly biodegradable materials, if not completely biodegradable, unlike bags made of corn starch. In fact, the presence of the bottom flap 3 allows to obtain bags 1 that are sufficiently resistant for the collection of organic waste without the need to add plastic materials to increase its resistance. 35

For the reasons listed above, bag 1 is particularly suitable both for collecting organic waste and for containing fresh food. However, its use is not limited to these sectors, for example the stock market could be used in general commercial fields, in the nursery sector, etc.

Claims (9)

1. A bag (1) for collecting organic compostable waste of the type with a lower base (4) and side walls (AF), which can be mounted from a preform (2) of paper material, folded and glued, having said preforms a bottom line (7), intended to form the bottom base (4) of said bag (1), which comprises inside a bottom flap (3) that can be moved between a non-operative position, in which said flap 5 bottom (3) is located substantially parallel to said side walls (AF), and an operating position, in which said bottom flap (3) is substantially parallel to said bottom base (4), when said bag is in a configuration upright, characterized in that said lower flap (3) is made of an absorbent and compostable material, and that said lower line (7) of the preform (2) has a number of stages, so that the lower base (4) of said bag (1) is of the “flat bottom” type in l to which said bottom flap and the bag 10 itself are biodegradable and compostable. 2. A bag according to claim 1, characterized in that said lower flap in said operative position overlaps at least partially with said lower base to act as an element that supports the contents of the bag. 3. A bag according to any one of the preceding claims, characterized in that said lower flap 15 is detachably fixed to at least a part of the bag. 4. A bag according to claim 3, characterized in that said lower flap is at least partially glued to a side wall of the bag. 5. A bag according to claim 3 or 4, characterized in that said lower flap can be transformed into said lower base of the bag, from the non-operative position. twenty A bag according to any one of the preceding claims, characterized in that said lower flap (3) is made of paper material. 7. A bag according to any one of the preceding claims, characterized in that said lower flap and the bag itself are made, at least partially, of recycled paper. A bag according to any one of the preceding claims, characterized in that it is made of a material at least partially permeable to air. 9. A method for collecting organic material from compostable waste with a bag, characterized in that said bag comprises a lower base (4) and side walls (AF), which can be mounted from a preform (2) of folded paper material and glued, said preform having a bottom line (7), provided to form the bottom base (4) of said bag (1), which comprises inside a bottom flap (3) that can be moved between a non-operative position , wherein said lower flap (3) is located substantially parallel to said side walls (AF), and an operational position, wherein said lower flap (3) is substantially parallel to said lower base (4), when said bag It is in an upright configuration, characterized in that said lower flap (3) is made of absorbent and compostable material, and that said lower line (7) of the preform (2) has a number of stages, so that the lower base ( 4) of said bag (1) is of the type "flat bottom", wherein said bottom flap and the bag itself are biodegradable and compostable.