TECHNICAL FIELD

The present invention relates to the technical field of packaging. It relates more particularly to the technical field of the packaging of products in a flexible package, formed by heat-sealing from a sheet of material.

Such packages are generally used for food products such as crisps, cereals, seeds, and many other bulk food products in the form of powder, particles or small items. Such packages may also be used for many other products, in the food industry (compotes, other liquid or pasty products) or in other industrial fields (e.g. for pharmaceutical or medicinal technical applications).

Such packages are also used, for example, to package small quantities of a product such as individual doses of sugar, freeze-dried coffee, concentrated milk. They are also used to pack small quantities of sweets, or for the individual packaging of small cakes and cookies. Such small packages, when they have an elongated shape, are often called "stick packs". Larger packages, e.g. for crisps or cereals, are often called "pillow pouch".

The invention thus relates to packages hereafter designated by the expression "soft container(s)". This expression relates, in the present document, to many types of packages obtained by heat-sealing of at least one sheet of laminate material, such as stick packs, and more generally to flexible containers or wrappers, also sometime called pouches.

BACKGROUND OF THE INVENTION

Toform such packages, one (or several) sheets of a material are folded or assembled to form a volume, e.g. a pouch, adapted to receive a product to be packaged. Assembly (if required), and closure of the package are performed by thermo-sealing (also called heat sealing). Usually, the sheets of material used to form such packages are multi-layer sheets, also called "laminates" or sheets of laminate material. They can comprise, by way of example:

- An outer layer, which will form the outer surface of the package, made of Polyethylene terephthalate (PET),

- A middle layer, made of aluminum,

- An inner layer, which will form the inner surface of the package, made of Polyethylene (PE).

Laminate materials also comprise, in the present document, co-extruded multilayer materials or coated paper, or any other multi-layered material suitable for forming a soft container by heat sealing.

More particularly a package can be formed as follows. A laminate goes through a so- called forming machine. In the forming machine, the laminate is folded into the shape of a tube. The adjacent edges of the sheet forming the tube are heat-sealed to close the wall of the tube. This is performed by a so-called side seal bar, which presses the adjacent edges of the laminates each other and heats them so that they are bound by welding of their respective inner layers.

The tube then passes between sealing jaws, also called sealing bars. The sealing jaws are brought together. They deform the tube of laminate material to press two opposite walls of said tube to form, by heat-sealing, a transversal sealing strip. Significant heat is applied by the jaws to the sealing strip, which has the effect of welding the inner layer at this location.

This achieves a complete seal without the need for adhesives

Optionally, the sealing jaws may also cut the so-formed sealed strips, to separate individual containers. More particularly, the sealing jaws may be configured to form two parallel sealing strips. Separation of the containers may be perform by cutting between the so formed two parallel sealing strips. Alternatively, a device distinct from the sealing jaws can be used for cutting. Known embodiments provide the possibility of cutting only some of the sealing strips to provide groups of soft containers linked to each other at the location of the uncut sealing strips.

The sealing jaws apply heat on the laminate from its outer side, i.e. on the outer layer of the laminate, to finally heat and thus seal the inner layer of the laminate. The material must therefore allow heat to pass through its thickness.

The heat transmission that is needed to obtain good sealing is hard to obtain. Indeed, in the area of the adjacent edges of the sheet of laminate material welded to form the tube, the heat must pass through four layers of laminate material. In addition, the excess thickness created in this zone by the superposition of four layers of laminated material creates variations in thickness between the sealing jaws. These variations in thickness, also called "thickness jumps" impair the transmission of heat by conduction from the sealing jaws to the inner layer.

As the material cannot be heated beyond a certain temperature because it would damage it, it follows that the speed of the packaging line is often limited by this sealing step by the sealing jaws. Beyond a certain speed of production line, a quality problem of the packages can arise, in particular because their closing by welding can present defects.

Furthermore, laminates composed of different materials have the important drawback that they are difficult to recycle.

An alternative to standard multi-material laminates are polyolefin laminates. Polyolefin laminates can be mechanically recycled. However, they also have drawbacks, in particular for use in large scale, high speed, production lines.

The polyolefin laminates are thicker than comparable multi-material laminates to ensure equivalent barrier properties and mechanical properties.

Because of the properties of the material itself and because of the required thickness of the polyolefin laminates, heat transfers within the polyolefin laminates are slower than within a multi-material laminate (i.e. from the outer side of the packaging, where heat is applied, to the inner side of the packaging, where enough heat must be applied to ensure sealing). A longer dwell time, i.e. sealing time, is needed in the sealing jaws.

Thanks to the properties of some of their layers (e.g. the PET and/or aluminium layer) the multi-material laminates are stable at higher sealing temperatures than polyolefin laminates. Therefore, polyolefin laminates cannot be heated to a temperature as high as multi-material laminates.

All this leads to a slower production speed when poly olefin laminates are used, in particular because the step of sealing by the sealing jaws is generally the step which limits the speed of the packaging line, as explained above.

In addition to the material composition, the format and shape of the formed pouches can further influence the above-described heat transmission issue. This is for example the case for so called "gusseted pouch". Gusseted pouches comprise gussets, i.e. material added to a flexible pouch to create more space and strengthen its structure. This however increases the number of "thickness jumps" along the seal, which impair heat transmission.

It is an object of the invention to provide a device and a method for the production of soft packages from sheets of laminate material, which allow the speed of the packaging line not to be limited by the step of sealing by the sealing jaws (and finally to speed-up the packaging line), and/or which allow use of sheets of material having worse heat transfer properties or heat stability properties than usually used multi-material laminate, such as poly olefin laminates, without limiting the packaging speed.

SUMMARY OF THE INVENTION

The invention thus relates to a device for forming a soft container from a sheet of laminate material when the sheet of laminate material passes through said device. The device comprises a dispensing system configured to supply the sheet of laminate material to a former, a former which is configured to fold the sheet of laminate material into a longitudinal tube shape by placing opposite edges of the sheet of laminate material in an adjacent position, a side seal bar which is configured to weld the adjacent edges of the sheet of laminate material which is folded into a tube-shape, and sealing means configured to press the tube formed by the sheet of laminate material and to form transversal sealing strips, thereby forming a closed volume of the soft container between two successive sealing strips. The device according to the present invention comprises a heating device configured to heat the sheet of laminate material upstream the sealing means without contact to the product.

The heating device makes it possible to heat the laminate material before it reaches the sealing means. The amount of energy that has to be brought to the sheet of laminate material by the sealing means to induce sealing and fluid tightness (by welding, i.e. by partial fusion and then solidification of the inner layer of the sheet of laminate material) is thus lower than when the sheet of laminate material is cold (i.e. at ambient temperature or so) when it reaches the means.

Compared to the prior art, this makes it possible to reduce the sealing time or dwell time in the sealing means, or, for a same sealing time: to use a thicker sheet of laminate material, and/or to use a sheet of laminate material having a lower heat conductivity from its outer layer to its inner layer, and/or to use a sheet of laminate material having a lower thermal stability, and/or to lower or to maintain the temperature of the sealing means to obtain sealing, and/or to lower the pressure applied by the sealing means, thereby addressing the risk of deformation of the container.

Lastly, this makes it possible to use a mechanically recyclable sheet of laminate material, such as a polyolefin laminate, while keeping a same high production (i.e. packaging) speed. 1. The heating device is preferably configured to heat the sheet of laminate material by convection or radiation. The heating device can comprise a heating chamber, the sheet of laminate material folded into a tube shape passing through or next to the heating chamber. Preferably, this is done without contact with the filling product. The heating device can comprise a hot air blower and a duct between the hot air blower and the heating chamber, such that the heating chamber may be fed with hot air by the hot air blower. The heating chamber can comprise at least one heating resistor. The heating device can be configured to generate air heated to a temperature comprised for example between 70°C and 100°C around or next to the sheet of laminate material folded into a longitudinal tube shape.

Many types of heating devices can be used in the invention. Creating at least one heating chamber partially or around the tube-shaped folded sheet of laminate material is an efficient way to heat it, with little energy loss. Convenient and efficient heating is achieved thanks to hot air blowing around the laminate material. The heating temperature is preferably chosen to be near but under the melting temperature of the inner layer of the laminate material. In addition, the melting temperature must not significantly impact the barrier and optical properties of the material.

The heating device can be configured to heat the sheet of laminate material between the side seal device and the sealing means. Heating the laminate just before the sealing means provides an optimal thermal energy supply. Above all, it makes it possible not to increase the coefficient of friction of the laminate material (which increases with its temperature) too early, which would create friction in the packaging machine that would impair the passage of the laminate material and could damage the laminate material. Generally, on Vertical Form Fill Seal machines, heating is carried out in an area in which the friction coefficient is not of importance to machinability.

According to a preferred embodiment of the invention, the sealing means are sealing jaws. The sealing jaws are configured to form the sealing strips by heat sealing. According to alternative embodiment, ultrasonic-welding means, vibration-welding means, or laser-welding means can be used.

The invention also relates to a system comprising the device as above described and a sheet of laminate material, wherein the laminate material is a polyolefin based laminate.

Polyolefin laminate can be recycled, while current laminate material used to form soft containers such as stick packs and pouches cannot be recycled or is difficult to recycle. Polyolefins provide a better working window (heat stability profile and sealing temperature). The device allow use of Homopolymer (also sometimes called monopolymer) laminates. Those laminates provides a better material purity for recycling. The polyolefin laminate can have a thickness for example comprised between 50 micrometers and 1500 micrometers, preferably 70 micrometers and 100 micrometers.

Such thickness provides, with a polyolefin laminate, adequate barrier properties. Polyolefin laminate with such thickness is one of the best alternative in terms of barrier properties to the current standard laminate material used to form soft containers.

The polyolefin laminate can comprise: an outer layer of oriented polypropylene (e.g. OPP 12), and an inner layer of polyethylene (e.g. PE 50).

The polyolefin laminate can further comprise a middle layer of monoaxially-oriented polypropylene (e.g. MOPP15).

The polyolefin laminate can alternatively be a monomaterial PE laminate or a monomaterial PP (polypropylene) laminate.

The laminate material can alternatively be a coated paper. Such coated paper may comprise an approximately 80 microns thick paper layer with a HDPE (High Density Polyethylene) coating or an acrylic coating to improve sealing and seal. Acrylic coating is preferred.

In fact, many types of coatings can be used in the present invention to obtain a coated paper as laminate material. A liquid coating can be used. Liquid coatings comprise aqueous dispersions of any kind of polymers. Such coating is applied in liquid form on a paper substrate, and is then dried to form a sealant layer.

Alternatively, coated paper can be obtained by extrusion coating, i.e. by application of molten plastics on a paper substrate.

For example, the following polymers can be used: polyethylene (PE), polypropylene (PP), Ethylene vinyl alcohol (EVOH), P-Hydroxystyrene (PHS, or4-vinylphenol), Polyethylene terephthalate (PET), PET-g (glucose modified PET).

Coated paper is recyclable by pulping which allows the cellulose to be separated from the coating material.

These example materials have been successfully tested by the applicant. Many other laminate materials can be used. The laminate material used in the invention is however preferably easily recyclable. The device provided in the invention also beneficially increases tightness on current laminates (laminates commonly used to date to form packages).

Generally, the laminate materials have an outer layer and optionally a middle layer that protect the contained product from air and optionally from light, and an inner layer that can easily melt to weld on itself. It must generally be suitable for food contact.

The invention also relates to a method for packaging a product in a soft container comprising the steps of:

• providing a system as above described;

• folding the sheet of laminate material into a longitudinal tube shape by placing opposite edges of the sheet of laminate material in an adjacent position,

• welding by heat sealing the adjacent edges of the sheet which is folded into a tube shape,

• introducing the product into the so formed tube, the product falling on a previously formed transversal sealing strip forming a bottom of the formed soft container;

• making the sheet of laminate material (1) folded into a tube shape progress through the device for forming a soft container of a given length, and • closing the soft container by forming a transversal sealing strip.

This method makes it possible to package a product, preferably a food product such as for example crisps, cereals, seeds, sugar, sweets, freeze-dried coffee any food product in the form of powder, grain or particles, cakes, cookies, compotes, liquid or pasty food products, at high speed and/or with an easy to recycle material. The method can also be used to package any other products, such as medical products, or technical products.

BRIEF DESCRIPTION OF THE DRAWINGS

- Figure 1 is a schematic three-dimensional view of a device for forming a soft container from a sheet of a laminate material, according to the state of the art;

- Figure 2 is a schematic three-dimensional view of a device for forming a soft container from a sheet of a laminate material according to an embodiment of the invention;

- Figure 3 is a schematic three-dimensional view of the device of Figure 2 in operation;

- Figure 4 is a diagram which illustrates the principle and the interest of the invention.

DETAILED DESCRIPTION

For a complete understanding of the present invention and the advantages thereof, reference is made to the following detailed description of the invention.

It should be appreciated that various embodiments of the present invention can be combined with other embodiments of the invention and are merely illustrative of the specific ways to make and use the invention and do not limit the scope of the invention when taken into consideration with the claims and the following detailed description.

As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to".

The invention is further described with reference to the illustrated example embodiments. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples. Figure 1 represents a device for forming a soft container from a sheet of a laminate material, according to the state of the art.

The device comprises a dispensing system for dispensing the sheet of laminated material 1. The sheet of laminate material 1 can have the form of a roll 2. The device comprises a reel 3 and guides 4 making it possible to supply the sheet of laminated material to the machine with a desired orientation and mechanical tension. In known devices, e.g. for forming stick packs, the sheet of laminated material dispensed by the dispensing system is cut longitudinally into several sheets of smaller width which can be each considered individually as a sheet of laminate material 1.

The device comprise a former 5, also called "forming shoulder" The former 5 folds the sheet of laminate material 1 into a tubular shape. To achieve this, the sheet slides along a domed member 6 formed around a filling tube 7.

Sufficient space for the passage of the sheet of laminate material 1 is provided between the domed member 6 and the filling tube 7.

The domed member 6 further comprises convergent guide surfaces 8, which places the two lateral edges 9 of the sheet of laminated material adjacent, in contact with one another. A tube is thus formed around the filling tube 7 by the sheet of laminated material 1.

The filling tube 7 extends under the domed member 6 (as shown in Figure 2). The tube of laminate material slides along the filling tube 7.

The adjacent edges of the sheet forming the tube are heat sealed together to close the wall of the tube of laminate material. This is performed in a side seal bar 9 which presses the adjacent lateral edges 9 of the sheet of laminate material 1 against each other and heats them so that they are bound by welding of their respective inner layers. Alternatively, the adjacent edges can be placed to overlap, and the inner layer of the above layer is sealed to the outer surface of the other edge to form a so called "lap seal".

The filling tube7 allows the product to be packaged to be introduced into the tube formed by the laminated sheet of material constituting the pack to be filled. This filling is carried out, in the represented example, by a funnel 11 situated in the upper part of the filling tube 7.

In order to form a container the tube formed by the sheet of laminated material must be closed , at its bottom and its top, in a direction transverse to the direction of the filling tube, of the tube formed by the sheet, and of the edges 9 of the sheet. The closure at the bottom of the soft container is formed by heat-sealing during the closure at the top of the previously formed soft container, as explained below.

In order to achieve this closure, the tube formed by the sheet of laminate material passes between sealing means. In the represented preferred embodiment, the sealing means are sealing jaws 12 (also called sealing bars). The sealing jaws 12, which are brought to high temperature, compress the tube formed by the sheet of laminated material 1. The sealing jaws 12 thus deform the tube of laminate material 1 so as to lay it flat. Two opposite walls of the tube of laminate material are thus pressed against each other. The inner layer of the sheet of laminate material 1 which is pressed between the sealing jaws melts at least partially so as to form a weld strip or sealing strip which closes the tube.

In the example shown here the sealing jaws 12 each have two parallel sealing portions located one above the other.

The upper sealing portion 13 of the sealing jaws 12 closes the bottom of the container currently being formed (before it is filled by introduction of product via the filling tube 7), while the lower sealing portion 14 of the sealing jaws closes the top of the previously formed container 15. Thus, the sealing jaws are configured to form two parallel sealing strips 17. The top part of the previous package and the bottom part of the next package are therefore closed simultaneously.

A slot 16 is formed between the upper sealing portion 13 and the lower sealing portion 14 of the sealing jaws 12. This slot 16 is configured for the passage of a cutting device for the separation of the containers. Separation of the soft containers may be perform by cutting between the so formed two parallel sealing strips. According to other embodiments, the cutting device could be a separate device. As explained above, a difficulty with this system consists in correctly closing the soft containers, in particular in the thick zone 18 of the containers, where the adjacent edges 9 of the sheet of laminate material 1 are folded down. This locally forms four layers of laminate material between the sealing jaws 12.

Furthermore, the thick zone 18 creates thickness variations (which may be called "thickness jumps") in the zones to be welded to close the container. Such variations in thickness impair a good transmission of heat between the sealing jaws 12.

The represented example pouch is a pillow pouch. In such example, along each sealing strips there is a two layer zone, a four layer zone (thick zone 18) and a two layer zone. In a gusseted pouch, the situation is even more complex and unfavorable for heat transmission, as along each sealing strips there is a four layer zone (due to a first side gusset), a two layer zone, a four layer zone (thick zone 18) a two layer zone, and a four layer zone (due to a second side gusset). Because heat transmission is difficult in the four layer zones, in the thickness jumps areas, and in two layer zones situated between four layer zones (in such case, the pressure applied by the sealing jaws is reduces in the two layer zone), and because the temperature of the sealing jaws is limited by the heat stability of the material used to form the containers, the speed of the packaging device and of the packaging line comprising this device is often limited by this sealing step for closing the containers.

In addition, the use of thicker materials, in particular easy to recycle materials, will require an even longer sealing time, which is not acceptable in an industrial process. Moreover, the envisaged easy to recycle materials are not as thermally stable as the materials commonly used so that it is not possible to heat them to the usually used high temperatures.

Figure 2 represents a device for forming a soft container from a sheet of a laminate material according to an embodiment of the invention. The device represented in Figure 2 is substantially identical to that represented in Figure 1, so that the above description of the device of Figure 1 applies to the device of Figure 2. The device of Figure 2 however differs from that of Figure 1 in that it comprise a heating device 19, which is described hereafter in detail.

In Figure 2, the device is shown while the laminated sheet of material 1 is not fully engaged on the filling tube 7. The lower part of the filling tube 7 is thus visible.

In the represented example embodiment, the heating device 19 substantially comprises two parts. The heating device 19 thus comprises a heating chamber 20. The heating system 19 also comprises a heat generator 21. The heat generator 21 produces, in the represented example, hot air. The heat generator 21 is connected fluidically to the heating chamber 20.

Hot air is thus transported from the heat generator 21 to the heating chamber 20.

The heating chamber 20 is located between the lower portion of the filling tube 7 and the sealing jaws 12.

The heating chamber 20 has an inlet 22 and an outlet 23. The heating chamber 20 is configured to be traversed by the tube formed by the sheet of laminate material 1, downstream of the forming machine 5 and the filling tube 7. This is shown in Figure 3.

The heating chamber 20 aims to provide thermal energy to the tube of laminate material that passes through it. This supply of thermal energy is carried out upstream of the sealing jaws. The laminate material is thus pre-heated before it reaches the sealing jaws 12. Consequently, the amount of energy to be brought to the material by the sealing jaws to obtain a good closure of the container is reduced.

The heating chamber 20 can for example have a cylindrical shape or a frustoconical shape. Such a shape is particularly well suited to obtain a good distribution of heat. The heating chamber can nevertheless have many other shapes.

The use of a heating chamber is optional in the invention. Nevertheless, the following aspects are important.

The supply of thermal energy must be made without contact if possible, that is to say by convection or radiation. Thus, at least the following heating technologies can be used: hot air heating, radiant heating, laser heating and any other contactless heating technology. For example, heating resistors can be provided in the heating chamber in alternative or complement to the introduction of hot air into the chamber.

Indeed the materials used to make soft containers have a coefficient of friction which increases very significantly when they are heated.

If the material was heated by conduction (i.e. by contact with a heating element), it would rub strongly on the heating element and it could be deformed or damaged. In addition, a strong force would be necessary to advance the material over the heating element.

It is also for this reason that the place in the device for forming soft containers where the pre-heating is carried out in the invention is important.

Preheating must be carried out before the tube of laminated materials reaches the sealing jaws 12. However, preheating must preferably be carried out after the laminated material tube has left the filling tube 7. Otherwise, the material would rub strongly along the filling tube 7. It would also rub on wheels provided for advancing the material along the filling tube 7.

Thanks to the heating means used in the invention, when the laminated material reaches the sealing jaws (as shown in Figure 3) it has been heated.

The principles implemented in the invention are summarized in Figure 4. Figure 4 is a diagram, which schematically represents the energy required to obtain a good seal during the manufacture of a soft container. Figure 4 is a diagram of principle which does not correspond exactly to physical reality but which illustrates in a simple way the parameters used when sealing the containers.

In Figure 4 there are shown two triangles. Each corner of those triangle corresponds to an important parameter in the sealing of a flexible container.

A first corner corresponds to the temperature of the sealing jaws.

A second corner corresponds to the pressure applied by the sealing jaws A third corner corresponds to the time required for sealing

The area of the triangle corresponds to the total energy necessary for sealing which must be brought to the location of the sealing jaws. What ultimately matters to obtain a good seal is this total amount of energy. The total amount of energy that is necessary depends on the laminated material used. It depends in particular on the thickness and the constitution of the laminated material.

The isosceles triangle corresponds to the situation according to the state of the art, namely the sealing of a flexible container formed from a conventional laminated material.

The other triangle represented in Figure 4 corresponds to the situation when one wishes to use another laminated material, for example based on polyolefin. It is considered for this illustration presented in Figure 4 that the thermal conductivity of the material does not change compared to the reference situation. The thermal stability of this material being lower than that of the materials generally used, the temperature of the sealing jaws must be lower compared to the reference situation. The pressure applied by the jaws depending on the mechanical constitution of the machine cannot be changed. In addition, too much pressure could damage the material of the soft container. As the total necessary energy represented by the area of the triangle must be maintained the only parameter on which it is possible to vary is the duration of the sealing, which must therefore be increased.

In order to reduce the sealing time to the nominal time necessary in the reference situation (isosceles triangle), it is therefore necessary to supply, by other means than by the sealing jaws, the energy represented by the hatched area of Figure 4. This energy supply is achieved by the heating means provided in the invention.

Thus, the preheating provided in the invention can make it possible to reduce the sealing time, and/or to reduce the temperature of the sealing jaws and/or to maintain these parameters when a less thermally conductive material is used. The invention is therefore of interest both for the manufacture of flexible containers with the materials currently used and with new materials, in particular easy to recycle materials. For example, the applicant has obtained the following experimental results, with a standard laminate material comprising an outer layer of PET12, a middle layer of Aluminum 7, and an inner layer of PE70, having a total thickness of around 89 pm.

Tests have been conducted with several sealing jaw temperatures with and without energy input by a heating system. The heating system used for the tests is a hot air device. It brings into a heating chamber air at 100 degrees with a flow rate of 500 liters per minute.

During these tests, the maximum production speed was determined allowing 100% of correctly sealed containers to be obtained.

With a sealing jaw temperature of 100 degrees Celsius, a maximum of five units per minute can be obtained without energy supplied by the heating system and eight units per minute can be obtained when energy is supplied by the heating system.

With a sealing jaw temperature of 110 degrees Celsius, a maximum of sixteen units per minute can be obtained without energy supplied by the heating system and twenty- three units per minute can be obtained when energy is supplied by the heating system.

With a sealing jaw temperature of 120 degrees Celsius, a maximum of twenty-eight units per minute can be obtained without energy supplied by the heating system and thirty- five units per minute can be obtained when energy is supplied by the heating system.

With a sealing jaw temperature of 130 degrees Celsius, a maximum of thirty-three units per minute can be obtained without energy supplied by the heating system and forty- five units per minute can be obtained when energy is supplied by the heating system.

A productivity gain of roughly around 40% can thus be achieved.

The invention thus allows for example use of a material such as a laminate comprising an outer layer of oriented polypropylene, a middle layer of monoaxially- oriented polypropylene, and an inner layer of polyethylene, to form a flexible container, with a production speed equal to or higher than the production speed obtained with a machine without a heating system and a standard laminate material as used in the above described tests. Successful tests have been performed with a laminate material comprising: - an outer layer of OPP 12 (Oriented Polypropylene 12), - a middle layer of MOPP 15 (Mono Oriented Polypropylene 15), and

- an inner layer of PE 50 (Polyethylene 50).

The invention may also be of particular interest for two-layer laminate materials.

It should be appreciated that various embodiments of apparatuses can be built according to the present invention.

Various configurations of heating system can be used. The parameters used in the invention must obviously be adapted according to the laminated materials used to form the container but also in some cases to the product to be packaged. For example, chocolate cannot be packaged at high temperature. In other embodiments, the invention provides a method for packaging a product in a soft container using the above-described device.

The invention thus provides an improvement to devices and methods for obtaining a soft container by heat sealing. It improves the productivity of a packaging line. It also makes it possible to use easy to recycle materials in industrial packaging lines. It allows in particular polyolefin based laminate materials to be used.