Title "Packaging for the containment and storage of solid fuel and its manufacturing process".

DESCRIPTION

This patent application relates to a flexible, biodegradable package for containing and storing solid fuel, particularly but not exclusively solid fuel in the form of pellets.

A method for making said packaging is also the subject matter of this patent application.

Field of application

The invention which is the subject matter of the present patent application is applied in the manufacture of flexible packages suitable for containing solid fuel material, preferably but not exclusively in granular form or in the form of pellets.

In particular, the invention which is the subject matter of the present patent application finds application in the field of making flexible packages capable of being sealed once the contents have been inserted in granular form or in the form of pellets.

State of the art

Conventionally, flexible packaging for solid fuels, also known as 'sack containers', essentially consists of plastic packages which, once emptied, are to be disposed of as reusable plastic material after appropriate treatment.

Typically, the plastic material from which flexible containers suitable for the contents in granular form or pellets are made is predominantly PE Polyethylene with thicknesses varying indicatively between 50 microns and 100 microns and obtained by means of well- known packaging techniques.

Regardless of the plastic material from which these packages are made, typically these packages must guarantee, in addition to flexibility, also sufficient strength to be able to fulfil the task of containers for products with a specific weight or sufficient strength to be filled, without breakage, for a specific volume. Conventionally, according to known art, bag-type packages are manufactured by means of appropriate devices and sealed once filling machines have inserted the contents, so that they can then be transported and delivered to the end user.

The main disadvantage of the known solutions lies in the fact that the material from which the sack-type confections suitable for containing material in the form of granules or pellets are made, once emptied, are destined to be disposed of as plastic material and thus only reusable after eventual treatment or only recyclable after appropriate processing.

An example of a type of unsealed bag type known to the state of the art is described in document EP3109179.

In the case of the aforementioned document, the bag has a substantially quadrangular shape with an opening at the top for access from the outside to the contents.

The invention described in document EP3109179 is conventionally made of plastic material and has the drawbacks already described.

In the state of the art, solutions are known for the realisation of containers made of biodegradable material particularly intended to contain material in granular form and/or pellets.

For example, document CN112832272 describes a biodegradable pack made of mineral fibre fabric suitably stitched to make a regular flat parallelepiped.

The type of pack described in document CN112832272 finds application in the field of forestry and in particular is suitable for the containment of plants that require a continuous exchange with the external environment, in particular with regard to the maintenance of the humidity of the roots and the soil in which the roots are sunk. Consequently, the material from which the container is made must allow if not facilitate the exchange between the contents and the environment, an exchange which, in the case of, for example, solid fuel in the form of pellets, would have to be avoided. Therefore, the solution described in the above-mentioned document cannot be adopted in the case of the intention to make bags for contents that are sensitive to external environmental conditions. Document EP3757295 describes a bag made of wire basically consisting of a mineral fibre coated with a sheath of biodegradable material. The invention described in document EP3757295 basically describes a net pack for the containment of discrete elements Such a pack can be used for protection, in the form of filters, or for transport, e.g. in hydraulic engineering, coastal protection or civil engineering, in particular road construction.

As described in the aforementioned document, the pack is filled with a material, e.g. sand, cement or stones, and can be unloaded and placed in the desired position depending on its use. In the respective position, the filled pack can serve to protect or weigh down an object, e.g. under water. In addition, the filled pack can be used to straighten, e.g. to lay pipes on an originally uneven surface.

Document CN204197560 describes a pack for transferring fuel in the form of biomass from one place to another, said pack being made of fabric.

The invention described in document CN204197560 therefore consists of a pack with an upper opening, exclusively for transferring material from one place to another, made of fabric and therefore not suitable for storing the material until it is used.

The invention described in EP3757295 cannot therefore be used for the production of pellet bags or alike as it is inherently designed for continuous exchange between contents and the environment outside the pack.

Also known in the state of the art are shopping bags and alike, which are made of biodegradable material and are intended to contain products, predominantly foodstuffs.

Conventionally, this type of packaging is equipped with a pair of handles and has an upper opening and is therefore not suitable for the purpose of the present patent application.

Also known in the art are bag-type packs made of biodegradable material that are closed at the base and have an upper opening without handles.

This type of biodegradable packaging is known to be intended for the delivery of wet waste and, once filled, is closed manually by means of string-type ties or the like. Due to the characteristic intended use, the breaking strength of this type of packaging is conditioned by the relative weight of the contents - the wet fraction to be delivered - and is therefore not feasible when filling with solid fuel is required.

Furthermore, the need to produce a manual closure by means of string or the like significantly conditions the tightness of the pack itself as well as preventing it from being stacked as the pressure of one pack on the other would inevitably lead to the pack breaking and the contents being lost.

Document W09822282 "PACKAGING ARTICLE" describes the realisation of a packaging of the bellows bag type suitable for containing bulk products.

According to the Description, the invention described in document W09822282 relates to the realisation of a packaging of the gusseted bag type made of multilayer film realised in plastic material, said packaging has being realised by heat sealing the multilayer film. According to document W09822282, the gusseted bag has strength characteristics derived from the plastic material in which it is made and commonly known in the plastic packaging industry.

In particular, document W09822282 describes a type of packaging in which there is a single bottom seal to create a "gusset pack" type configuration that is not suitable for containing material intended for storage prior to its use.

Document EP1153743 "BIODEGRADABLE BAG" describes a bag made of biodegradable material that can be heat-sealed at low temperature, that does not develop ripple effects from the heat of the heat sealing process, and that presents transparency and degradability in the natural environment. In particular, the invention described in Document EP1153743 relates to the manufacture of a biodegradable bag comprising a laminate whose main component is a polymer of the polylactic acid family and a film whose main component is an aliphatic polyester having a crystallising heat of fusion D Hm (J/g) of 45£ D Hm£ 55.

According to the invention described in EP1153743, thermowelding is conventionally a welding method in which flaps of material are overlapped and joined together by heat and pressure, conventionally by means of heating rods or the like.

According to the invention described in EP1153743, the construction of a container made of polylactic acid has the disadvantage that this material, transformed into a film, is not particularly resistant to impact. If the polylactic acid is mixed with other polyesters, this improves the impact resistance, but the resulting material has further disadvantages in the form of elongation to the point of rupture when exposed to temperatures moderately above room temperature, as well as reduced strength at the heat-sealing points. The solution proposed and described in document EP1153743 is therefore that of a packaging material that can be heat-sealed without the material itself changing its structure during the heat sealing process, and at the same time be sufficiently resistant even at temperatures above room temperature.

The solution described in document EP1153743 is therefore to couple a polylactic acid film to an aliphatic polyester film, obtaining a laminate having a polylactic acid surface and the opposite aliphatic polyester surface, and to perform the thermowelding exclusively on the aliphatic polyester surfaces of two overlapping laminates so that the polylactic acid surfaces of said overlapping laminates are external and not involved in the thermowelding process.

In particular, in order to obtain the solution described in document EP1153743, the film must have a biaxial orientation, i.e. it must exhibit stretchability characteristics in both longitudinal and lateral directions.

Document EP1153743 sets forth a series of conventionally known methods for obtaining said condition as well as a series of conventionally known methods for obtaining the laminate by bonding between the polyester film and the polylactic acid film.

According to document EP1153743, the product obtained consists of a pouch made of a biaxially oriented laminate consisting of an inner film of aliphatic polyester and an outer film of polylactic acid, said pouch being welded at the bottom and sides and having a hinge at the top. The invention described in document EP1153743 therefore relates to the realisation of a packaging for presents has an inner layer in the form of a film the main component of which is an aliphatic polyester so that in the sealing step by melting the aliphatic polyester film, the melting temperature is lower than the melting point of the polymer of the polylactic acid family in the outer layer. The solution described in EP1153743 involves a process of making the laminate and a process of making two side heat seals and a bottom heat seal which is particularly complex and costly in a context of making packaging for material intended for storage.

The task of the invention which is the subject-matter of the present patent application is therefore to realise a bag-type packaging suitable for the storage and containment of solid fuel, particularly but not exclusively pellets, which has performances of robustness and insulation from the external environment quite similar to the known packaging, and which is made of a biodegradable material and realised according to a specific process.

A further task of the invention which is the subject-matter of the present patent application is to make a biodegradable bag-type packaging suitable for the storage and containment of solid fuel, particularly but not exclusively made of pellets and sealable in the absence of components that compromise its biodegradability.

A further task of the invention which is the subject of this patent application is to make a biodegradable bag type packaging suitable for storing and containing solid fuel, particularly but not exclusively in the form of pellets, which in the case of overlapping of more than one bag containing the usual fuel maintains the sealed condition of the contents, preventing their leakage.

Brief description of the figures

Fig 1: Example view of the film from which the patent-applied pack is made;

Fig 2: Illustrative view of a first stage of making the patent application package;

Fig 3: Example view of the intermediate obtained from the first stage of realisation of the patent application package; Fig 4: Example front view of the intermediate obtained from the second stage of realisation of the packaging covered by the present patent application;

Fig 5: Example front view of the intermediate obtained from the second stage of making the packaging subject of the present patent application;

Fig 6: Example view of the intermediate following the filling stage; Fig 7: Example view of the first front surface of the flexible solid fuel packaging according to the invention of the present patent application;

Fig 7.a: Example view of the second front surface of the flexible packaging for solid fuel according to the invention of the present patent application;

Fig 8: Exemplary embodiment of the stages for making the package according to the invention of the present patent application. Detailed description of the invention

With reference to the appended Figures, the flexible packaging for solid fuel, particularly but not exclusively pellets, of the sack type is indicated by numeral 9.

According to the invention which is the subject matter of the present patent application, the flexible packaging for solid fuel, particularly but not exclusively pellets (9, Fig 7, Fig 7.a) is made of biodegradable material having specific characteristics in terms of robustness and insulation comparable to known containers, overcoming the disadvantages of the state of the art with regard to the disposal of the packaging once the contents have been emptied. According to the invention subject matter of the present patent application, the package (9) has a first surface (9.1, Fig 7) and a second surface (9.2, Fig 7.a), a lower closed surface (6, Fig 7, Fig 7.a) and an upper closed surface (7, Fig 7, Fig 7.a).

In particular, the first surface (9.1, Fig 7) of the package (9) has an overlapping area (4, Fig 3, Fig 6, Fig 7) of the right (2.1 Fig 1, Fig 2, Fig 3) and left (2.2 Fig 1, Fig 2, Fig 3) side ends of a film (1) made of biodegradable material. According to the invention which is the subject matter of the present patent application, the lower closed surface (6, Fig 2, Fig 4, Fig 6, Fig 7, Fig 7.a) is made by overlapping the lower flaps (3.1,3.2 Fig 3) of the film (1) made of biodegradable material and the upper closed surface (7, Fig 7, Fig 7.a) is made by overlapping the upper flaps (4.1,4.2, Fig 3) of the film (1) made of biodegradable material.

In a preferred, but not exclusive, embodiment, the association of the right (2.1) and left (2.2) side ends of the film (1) made of biodegradable material to realise the overlapping area (4) present on the first surface (9.1) of the package (9), the closure at the base by association of the lower flaps (3.1, 3.2) to realise the lower closed surface (6) of the package (9) and the closure by association of the upper flaps (4.1, 4.2) to realise the upper closed surface (7) is carried out by thermoforming under heat at a temperature £ 130°C and in the absence of glues or resins or adhesives.

According to the invention which is the subject matter of the present patent application, the film (1, Fig. 1) made of biodegradable material with which the package (9) described is made, is obtained by extrusion of biodegradable thermoplastic compount which in turn is obtained by mixing biodegradable polyesters.

In particular, the film (1) of biodegradable material obtained has a thickness of between 100 microns and 120 microns. The technical characteristics of the biodegradable film from which the package (9) covered by the present patent application is made are shown in Table 1.

Table 1

Description of the process for making the packaging According to the invention which is the subject matter of this patent application, the package (9) described is made according to the steps detailed below.

First step: Making the film from biodegradable material.

Referring to Fig 1 and Fig 8, the biodegradable polystyrene mixture (20, Fig 8) is suitably processed and by extrusion a flat biodegradable film (1, Fig 1, Fig 8) is obtained, which is subsequently wound onto a reel and subsequently processed by a common device for making sack-type confections.

Second step: realisation of the intermediate pack configuration. A portion of film (1), previously cut, is reversibly wound to a cylindrical body (5, Fig 2, Fig 8) so that the right side end (2.2, Fig 2, Fig 3) and the left side end (2.1, Fig 2, Fig 3) can overlap and can be reciprocally associated to make an intermediate pack configuration (1.1, Fig 3) having a substantially cylindrical configuration having side surfaces (9.1, 9.2) and open top and bottom ends.

By association of the lower flaps (3.1,3.2) created by the reversible wrapping of the foil (1) to the cylindrical body (5), a closure at the base (6) of the intermediate configuration (1.1) is obtained. Once the cylindrical body (5) is removed, a configuration of the intermediate package (1.1, Fig 5) is obtained which has a closed lower surface (6) and an open upper surface.

Third stage: filling

With reference to Fig 6 and Fig 6, the intermediate pack configuration is then filled with a predetermined amount of solid fuel.

Fourth stage: upper closure

With reference to Fig 7, Fig 7.a and Fig 8, once the predetermined amount of solid fuel has been placed in the intermediate pack configuration (1.1), the upper closure is made by combining the upper flaps (4.1,4.2) to create the final pack configuration (9).

The flexible package (9) for solid fuel obtained according to the process described above is therefore constituted by an intermediate configuration (1.1) constituted, in turn, by a film (1) with flat development in biodegradable material whose lateral ends (2.1,2.2) are reciprocally and irreversibly associated in a longitudinal sense to create an association area (4), said association area (4) being realised only on a front surface (Fig. 3,4) of said intermediate (1. 1) while on the opposite surface (Fig 5) the intermediate (1.1) presents a seamless surface exclusively formed by the film (1) and whose lower ends (3.1,3.2) and upper ends (4.1,4.2) are associated in a transverse direction to create two distinct association areas (6,7) parallel to and transverse to the association area (4).

The flexible packaging (9) for solid fuel thus obtained is therefore substantially made of biodegradable material, presenting performance characteristics, in terms of robustness, insulation from the external environment and resistance to breakage, comparable to a flexible packaging made of plastic material, being however manageable as biodegradable waste once the packaging function has been fulfilled.

In a preferential, but not exclusive, form of realisation, on the surface of the pack realised as described, it is possible to realise a microperforation in order to allow the escape of any moisture present in the content. The creation of microperforations on the entire surface of the pack thus realised also allows a friction effect in the case of a series of overlapping packs, such as to counteract a reciprocal sliding effect of the packs placed one on top of the other. The pack realised as described above can also be characterised by prints reproduced on the lateral surfaces, these prints being made with biodegradable inks in order to maintain the uniqueness of the product thus realised.