BE1030529B1 - VACUUM PACKAGING AND METHOD OF VACUUM PACKAGING - Google Patents

Abstract

A package that packs a product under vacuum, preferably a cushion-type package, formed by a polymer film, the polymer film comprising: an outer film layer and an inner film layer. The outer film layer is a first polyethylene film layer. The inner film layer is a thermally sealable second polyethylene film layer with different thermal properties than the first polyethylene film layer. The package is provided with at least one opening on one side thereof, wherein this opening is designed for vacuum packaging and is closed by at least one closing element.

Description

N N BE2022/5368

VACUUM PACKAGING AND METHOD OF VACUUM PACKAGING

TECHNICAL FIELD

The invention relates to vacuum packaging and vacuum packaging methods.

Special embodiments relate to vacuum packaging using polymer films.

BACKGROUND

In the field of packaging, there is an increasing need for packaging that is more recyclable. This is especially true for packaging made mainly from polymers, which by nature usually come from fossil raw materials. Such increased recyclability offers clear benefits as the packaging will waste fewer resources and, at the end of its life, will not simply end up as waste to be landfilled or incinerated for energy recovery. In the case of polymer-based packaging, all or part of the packaging can be made of polymer films. However, polymer films are usually made of several layers of polymers of different classes, which drastically complicates the polymer sorting and recycling process. It would therefore be advantageous to have packaging with improved recyclability, while still allowing for widespread adoption of packaging technologies such as vacuum packaging. Furthermore, using vacuum packaging, filled flexible packaging can easily be stacked directly for transport eliminating the need for secondary packaging, e.g. corrugated cardboard boxes, reduces and contributes to a reduced use of packaging materials.

Indeed, in state-of-the-art solutions, polymer films for polymer-based packaging are based on a multi-layer composition, where each layer has different properties regarding flexibility, puncture resistance, tear resistance, barrier properties, seal application temperature, seal integrity , stretchability, etc. Each of the layers that make up the film also has a different role that affects the mechanical requirements for the respective layer, and therefore the chemical composition of the respective layer. These different compositions influence the suitability of the polymer-based packaging for recycling. So, there is a need to properly address this eligibility

RESUME

The purpose of embodiments of the invention is to provide a package and method of vacuum packaging that allows increased recyclability of the package and reduced use of waste material when these filled packages are shipped.

According to a first aspect of the invention, a package is provided that packs a product under vacuum, preferably a pillow-type package. The packaging is formed by a polymer film. The polymer film includes: an outer film layer and an inner film layer. The outer film layer is a first polyethylene film layer. The inner film layer is a thermally sealable second polyethylene film layer with different thermal properties than the first polyethylene film layer. For example, the seal initiation temperature of the inner film layer can be between 105°C and 115°C and the seal initiation temperature of the outer film layer can be between 125°C and 135°C. The packaging is provided with at least one opening on one side thereof. The at least one opening is designed for vacuum packaging and to be closed by at least one closing element.

By having a package with two layers of polymer material of the same class, i.e. a mono-material package, the overall composition of the material that makes up the package is more uniform. And the more uniform a material is, the easier it can be recycled. Depending on the embodiment, the different layers of the polymer film can be laminated or coextruded together.

At the same time, the product packaged in the packaging must be protected from the environment of the packaging to prevent deterioration due to, for example, moisture absorption or oxidation. The packaging must also prevent the packaged product from spilling out of the packaging.

Typically, the individually taken packaging has a mainly rectangular shape.

To achieve that shape, the polymer film can first be sealed along one longitudinal edge to define a tube, then sealed at a lower edge, filled, and finally sealed at an upper edge. Alternatively, the packaging can also be achieved by starting from a tubular polymer film that is fed into a vertical form-fill-seal (VFFS) machine to be sealed at a bottom edge, filled and finally sealed at a top edge . The inner film layer is therefore designed to allow sealing. Conventional heat sealing is accomplished by locally applying heat for a specified period of time and with a specified pressure to the polymer layers at the sealing site. However, when the inner film layer is heated above its seal initiation temperature, the outer film layer which is also exposed to the local applied heat preferably has a temperature lower than its seal initiation temperature. Therefore, it is important that the first polyethylene film layer and the second polyethylene film layer have different thermal properties. More specifically, the seal initiation temperature of the second polyethylene film layer is preferably significantly below the seal initiation temperature of the first polyethylene film layer. For example, the seal initiation temperature of the inner film layer may be between 105°C and 115°C and the seal initiation temperature of the outer film layer may be between 125°C and 135°C.

Furthermore, to achieve vacuum in the package, at least one opening is provided.

The placement of the at least one opening on the side of the packaging is particularly suitable for removing the air in the packaging in a horizontal position of the packaging.

This way, the packages can easily be placed on their side for palletization and transport. After all, vacuuming the flexible packaging often "fixes" the shape of the flexible packaging around the packaged product and determines its load. By allowing vacuum extraction of the packaging in a horizontal position, the packaging can be more easily stacked on pallets and thus increases transport safety.

According to a preferred embodiment, the outer film layer and the inner film layer comprise >85.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the respective first polyethylene film layer and the second polyethylene film layer.

In this way, a large part of the polymer material that makes up the polymer film of the packaging is made from a polymer of the same class. Suitability for the recyclability of the packaging is therefore assured.

According to a preferred embodiment, the outer film layer has a thickness between 8um and 50um, preferably between 10um and 40um, more preferably between 10um and 30um.

In this way, a small amount of material is used for the outer film layer, limiting the potential waste of raw materials, while still ensuring mechanical strength.

According to a preferred embodiment, the inner film layer has a thickness between 60um and 150um.

In this way an appropriate thickness for the inner film layer is achieved, so that the strength of the closure and the integrity of the package are maintained.

According to an exemplary embodiment, the outer film layer is a machine direction oriented polyethylene (MDOPE) film layer.

It is noted that MDOPE film layers can be manufactured from various grades of high-density PE (HDPE) and/or grades or blends of medium-density PE (MDPE) and linear low-density PE (LLDPE).

In this way, the thickness of the outer film layer is reduced while still achieving mechanical properties for the film layer that are better than those of a conventional polyethylene film layer of a comparable thickness produced via processes such as casting extrusion or blown film extrusion without orientation stretching. In the production of a machine direction oriented polyethylene film, the initial thickness is greater than the final thickness and the film is subjected to an orientation process at temperatures lower than the melting temperature of the polyethylene material. Such orientation causes the film to stretch, reducing its thickness. Depending on the embodiment, the outer film layer can be subjected to a mono or bi-directional orientation process.

According to a preferred embodiment, the inner film layer is a PE/EVOH/PE, a PE/SiOx, a PF/AIOx, or a metallized PE film layer, preferably a PE/EVOH/PE film layer.

In this way, the inner film layer includes enhanced oxygen and migration barrier properties to protect the packaged product, such as a food product, from spoilage.

Examples are fat oxidation, loss of aroma and unwanted migration and contamination from the outside air into the packaging.

According to an exemplary embodiment, the polymer film is a laminated film or a coextruded film.

In this way, the adhesion of the different film layers ensures better mechanical properties of the polymer film. The laminate can be formed using an adhesive layer between the outer film layer and the inner film layer. The adhesive layer can be a solvent-based adhesive or a solvent-free adhesive, for example a polyurethane-based adhesive. The laminate can be formed by applying the adhesive layer to either the inner film layer or the outer film layer, contacting the inner film layer and the outer film layer, and applying a contact pressure.

According to a further embodiment, the adhesive can be a hot-melt adhesive that is applied as an adhesive layer in molten form. The hot melt adhesive may be a thermoplastic material with adhesion capabilities to both the inner film layer and the outer film layer, for example a polyethylene-based material.

Alternatively, the polymer film can be prepared by a water-cooled co-extrusion blowing process, an air-cooled co-extrusion blowing process, a co-extrusion T-die process, a dry lamination process or an extrusion lamination process.

According to an exemplary embodiment, the package further comprises an intermediate film layer between the outer film layer and the inner film layer. The intermediate film layer is a third polyethylene film layer, preferably a coextruded PE/EVOH/PE film layer.

Depending on the embodiments, the intermediate film layer has a thickness between 8um and 50um, preferably between 10um and 40um, more preferably between 104m and 30um.

In this way the packaging retains its suitability for recycling. By adding this polymer interlayer, the polymer film has improved mechanical properties, such as a larger closing window, puncture resistance, tear resistance, and environmental barrier properties.

According to a preferred embodiment, the intermediate film layer comprises 285.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the third polyethylene film layer.

As noted above, having a high fraction of polymer material of the same class that composes the polymer film from which the packaging is made improves its recycling suitability.

According to an exemplary embodiment, the opening is formed by laser cutting.

In this way the at least one opening can be formed with greater precision. In addition, sharp edges can be obtained at the cutting surface, reducing the risk of tearing the material during vacuuming of the package.

Depending on the embodiment, the opening can be provided in the polymer film in sheet or roll condition before the film is formed into a tube, after the film is formed into a tube, or after the film is filled with the product. In the most favorable embodiment, the opening is made when the polymer film is in the sheet or roll state.

In addition, the opening is shaped in such a way that it is preferably located in the middle of the side of the package. This allows a more uniform vacuuming of the package.

According to an exemplary embodiment, the opening comprises an opening with a rounded edge.

Preferably, the at least one opening has a substantially oval-shaped opening.

In this way, cracks in the package due to a sharp angle change in the shape of the at least one opening are reduced. Depending on embodiments, the at least one opening can be one opening or several, preferably one opening.

According to an exemplary embodiment, the at least one opening has a longest dimension (L) between 1mm and 20mm, preferably between 5mm and 18mm, more preferably between 8mm and 15mm.

In this way, the influence of the opening on the structural integrity of the package is limited. In addition, the longest dimension of the opening is preferably smaller than the shortest dimension of an individual unit of the packaged product, so that this individual unit of the product cannot escape from the package during vacuuming.

It is noted that the evacuation of air from the package can be carried out directly through the opening, or, alternatively, after at least one valve has been fitted into the opening using an adhesive or by welding.

According to a preferred embodiment, the at least one opening has a shortest dimension (w) between 1 and 10 mm, preferably between 1 and 8 mm.

In this way, the evacuation of air from the package through the at least one opening is not hindered and can be achieved relatively quickly, preferably in a time period of less than 10 seconds.

Depending on embodiments, the evacuation of air from the package through the at least one opening can be carried out manually or in an automatic manner, preferably in an automatic manner.

According to an exemplary embodiment, the at least one closing element comprises a sticker designed to seal the at least one opening.

In this way the at least one opening can be sealed in a simple manner. The sticker has an adhesive layer on the side that faces the packaging to ensure the adhesive strength of the sticker on the packaging. Preferably, the sticker has a round shape and a diameter of at least 100 mm, to prevent air from entering from the opening, in particular through the creation of air tunnels. Preferably, the sticker comprises >85.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the sticker.

In one embodiment at least one valve is provided on the at least one opening; the at least one valve is then sealed in the at least one opening. The valve may be self-closing after removal of the vacuum machine. In addition, a sticker can be applied over the at least one valve.

According to a preferred embodiment, the package has a first and a second side. The first side is sealed to the second side along at least one edge seal of the first and second sides. The at least one opening is provided in one of the first and the second sides

In this way, because the package has two sides, the horizontal laying of the package is simplified, as well as the use of a machine for vacuuming through the at least one opening. Laying down horizontally for vacuuming is also beneficial for products whose individual units are in the millimeter range and above and which have gaps.

According to an exemplary embodiment, the package has a lengthwise and a widthwise direction.

The at least one edge seal comprises a longitudinal edge seal, a lower edge seal in the width direction and an upper edge seal in the width direction.

In this way a cushion-type packaging is obtained that can be processed in a simple manner. When the polymer film is formed as a tube, a top edge seal of a currently filled package can be performed simultaneously with a bottom edge seal of the next package in line. In addition, the cutting between the upper edge seal and the lower edge seal can take place simultaneously with the sealing to separate the currently filled package from the next package.

According to a preferred embodiment, the lower edge seal and the upper edge seal both have a seal strength greater than 30N/15mm, preferably greater than 40N/15mm, more preferably greater than 50N/15mm, most preferably greater than 60N/15mm .

In addition, the longitudinal edge seal may have a sealing strength greater than 30 N/15mm, preferably greater than 40 N/15mm, more preferably greater than 50 N/15mm, most preferably greater than 60 N/15mm .

In this way, high sealing strength is achieved, which prevents the package from being unintentionally opened from the lower edge seal or the upper edge seal during transport, handling or the shelf life of the pallet. The skilled person will understand that the same advantages apply to the longitudinal edge seal.

According to an exemplary embodiment, the first side and the second side both have a side length (Ls) between 200mm and 800mm, preferably between 400mm and 700mm, and have a side width (ws) between 100mm and 500mm, preferably between 300mm and 500mm.

According to a preferred embodiment, the package contains a load between 3kg and 30kg, preferably between 5kg and 25kg.

According to an exemplary embodiment, the packaged product in the package is particles, preferably foodstuffs, for example chocolate drops. More specifically, the particles may have a disc-shaped shape with a diameter between 28 mm and 35 mm and a height between 4 mm and 8 mm. The skilled person will understand that the at least one opening is so large that the particles cannot pass through the at least one opening before or during vacuuming.

Particles are substances that are neither gaseous, liquid nor powdery, but which can be divided into a large number of individual units whose size can be of the order of millimeters and more.

According to a preferred embodiment, the polymer film has a puncture resistance of greater than 3N, preferably greater than 5N, and still greater than 10N.

This way, products with sharp edges can still be packaged safely and under vacuum.

When packaging these products, it is important that no perforation occurs, neither during the packaging process nor during the shelf life of the product, including transport and use of the packaging. If perforation occurs, the product is exposed to the environment and will therefore suffer a loss of quality. This must be avoided.

Those skilled in the art will understand that the technical considerations and advantages described above for packaging embodiments also apply to the corresponding method for vacuum sealing packaging embodiments described below, mutatis mutandis.

According to a second aspect of the invention, a method is provided for packaging particles, preferably foodstuffs, in a package. The method comprises the steps of: - providing a tube made of a polymer film with at least one opening, wherein the polymer film is adapted to form the package and comprises an outer film layer and an inner film layer, the outer film layer being a first polyethylene film layer and the inner film layer is a thermally sealable second polyethylene film layer with different thermal properties than the first polyethylene film layer; - forming a bottom edge seal of the package by sealing opposing portions of the inner film layer; - filling the package with the particles from a top direction; - forming an upper edge seal of the package above the filled particles by sealing opposing parts of the inner film layer; - optionally, move the packaging from a vertical to a horizontal position; - vacuuming the package through the at least one opening; - closing the at least one opening.

According to an exemplary embodiment, the vacuum drawing step is performed on a substantially horizontally filled package.

In this way, the distribution of the product over the length of the package before vacuuming is almost even, which simplifies the handling and subsequent palletization of the package.

According to a preferred embodiment, the method further comprises the steps of: - after the step of forming an upper edge seal, cutting the filled package from the tube to obtain a first filled package under vacuum, and repeating the steps of filling and forming an upper edge seal to obtain multiple filled packages; - stacking the multiple filled packages on a pallet in layers, whereby adjacent filled packages of the stacked multiple filled packages are in direct contact.

In this way, additional material, such as corrugated cardboard boxes to package individual or multiple filled packages, can be avoided. The described method thus makes it possible to reduce the production of waste material after shipment of the packages, while packing more product weight per individual pallet.

In a preferred embodiment, the different layers of packaging on the pallet are separated by anti-slip sheets made of paper, to improve the overall stability of the load on the pallet. In addition, a PE stretch film can be used to wrap around the stack of filled packages, further stabilizing the load on the pallet. Alternatively, the different layers of packaging can be secured together with glue.

According to an exemplary embodiment, the step of closing the at least one opening comprises providing at least one closing element, preferably a sticker, over the at least one opening.

According to a preferred embodiment, a vacuum level corresponding to a maximum absolute pressure of 600mbar, preferably a vacuum level corresponding to a maximum absolute pressure of 400mbar, is obtained during the step of vacuuming the package.

In this way, an evacuation of the air is carried out below a predetermined acceptable threshold, so that the damage to the packaged product by the remaining air in the package is limited.

According to an exemplary embodiment, the at least one opening is provided by cutting, preferably laser cutting.

According to a preferred embodiment, the package is filled with a load of particles between 5 kg and 25 kg, preferably between 10 kg and 20 kg.

According to an exemplary embodiment, the dimensions of at least one opening are smaller than the dimensions of a particle of the particles.

BRIEF DESCRIPTION OF THE FIGURES

These and other aspects of the present invention will now be described in more detail with reference to the accompanying drawings which show a presently preferred embodiment.

Like numbers refer to like features in the drawings.

Figures 1A-1B show schematic cross-sections of a polymer film for packaging according to various exemplary embodiments of the invention;

Figures 2A-2B illustrate schematic top views of packages according to further exemplary embodiments of the invention;

Figure 3 shows a flowchart of a method for vacuum packaging particles in a package according to exemplary embodiments of the invention.

DESCRIPTION OF THE EMBODIMENTS

Figures 1A-1B schematically show cross-sections of a polymer film for packaging according to various exemplary embodiments of the present invention.

The aim of the invention is to provide a package that packs a product under vacuum. The packaging is formed by a polymer film 1.1°.

In the embodiment of Fig. 1A, the polymer film 1 comprises an outer film layer 10 and an inner film layer 20. The outer film layer 10 and the inner film layer 20 have different thermal properties. More specifically, the outer film layer 10 and the inner film layer 20 may have different seal initiation temperatures, with the seal initiation temperature of the inner film layer 20 being lower than the seal initiation temperature of the outer film layer 10. For example, the seal initiation temperature of the inner film layer 20 may be between 105° C and 115°C, and the seal initiation temperature of the outer film layer 10 is between 125°C and 135°C.

Both the outer film layer 10 and the inner film layer 20 are polyethylene film layers. The outer film layer 10 is hereinafter referred to as the first polyethylene film layer and the two terms may be used interchangeably. The inner film layer 20 is hereinafter referred to as the second polyethylene film layer and the two terms may be used interchangeably. The inner film layer 20 is thermally sealable. In other words, when an area is locally heated, the heated area of the inner film layer 20 will melt, allowing another area of overlapping inner film layer 20 to adhere after cooling.

The first polyethylene film layer 10 and the second polyethylene film layer 20 together form the polymer film 1 by being laminated together or by being co-extruded together. Preferably, the laminate can be formed using an adhesive layer between the first polyethylene film layer 10 and the second polyethylene film layer 20. The adhesive layer can be a solvent-based adhesive or a solvent-free adhesive, for example a polyurethane-based adhesive. The laminate can be formed by applying the adhesive layer to one of the first polyethylene film layer 10 or the second polyethylene film layer 20, contacting the first polyethylene film layer 10 and the second polyethylene film layer 20, and applying a contact pressure. In another embodiment, the adhesive layer can be a hot melt adhesive that is applied as an adhesive layer in molten form. The hot melt adhesive may be a thermoplastic material with adhesion capabilities to both the first polyethylene film layer 10 and the second polyethylene film layer 20, for example a polyethylene based material. Alternatively, the polymer film can be prepared by a water-cooled coextrusion inflation process, an air-cooled coextrusion inflation process, a coextrusion T-die (T-die in English) process, a dry lamination process or an extrusion lamination process.

In one embodiment, the first polyethylene film layer 10 comprises 285.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the first polyethylene film layer. In addition, the first polyethylene film layer 10 may be a machine direction-oriented polyethylene film layer. In the production of a machine direction oriented polyethylene film, the starting thickness is greater than the final thickness and the film is subjected to an orientation process at temperatures below the melting temperature of the polyethylene material. Such orientation causes the film to stretch, reducing its thickness. Depending on the embodiment, the first polyethylene film layer 10 can be subjected to an orientation process in one or two directions.

The first polyethylene film 10 may have a first thickness tl, viewed in the plane of the section. The first thickness tl can be between 8um and 50um, preferably between 10um and 40um, more preferably between 10um and 304m.

Similar to the first polyethylene film layer 10, the second polyethylene film layer 20 comprises, in one embodiment, >85.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the second polyethylene film layer 20.

In addition, the second polyethylene film layer 20 can be a PE/EVOH/PE, a PE/SiOx, a

PE/AIOx, or a metallized PE film layer, preferably a PE/EVOH/PE film layer. The second polyethylene film layer 20 may have a second thickness t2, viewed in the plane of the section. The second thickness t2 can be between 60um and 150um.

Fig. 1B differs from the above-described embodiment of Fig. 1A only in that the polymer film 1' further comprises an intermediate film layer 30' between an outer film layer 10' and an inner film layer 20'. The intermediate film layer 30' is referred to as a third polyethylene film layer and the two terms may be used interchangeably. In one embodiment, the third polyethylene film layer 30' comprises 285.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene relative to the weight of the third polyethylene film layer 30. '. In addition, the third polyethylene film layer 30' can be a

PE/EVOH/PE film layer. The intermediate film layer 30' may have a third thickness t3', viewed in the plane of the section. The third thickness £3' can be between 8um and 50um, preferably between 10um and 40um, more preferably between 10um and 30um.

Figures 2A-2B illustrate schematic top views of packages according to further exemplary embodiments of the present invention. The packages in the embodiment of Fig. 2A-2B are formed by a polymer film as described with reference to Fig. 1A or Fig. 1B. The embodiment shown in Fig.2B is the preferred embodiment of the invention.

In both embodiments of Fig. 2A-2B, the package 100 has a first side 110 and a second side 120. The first side 110 is sealed to the second side 120 along at least one edge seal 50, 60, 115 of the first side 110 and the second side 120. More specifically, the at least one edge seal 50, 60, 115 is obtained by locally heating a sealing area at the location where a seal is required to a temperature above the seal initiation temperature of an inner film layer containing the polymer film composes. The sealing zone is defined by an overlap of a first part of the inner film layer belonging to the first side 110 and a second part of the inner film layer belonging to the second side 120.

In another embodiment, the first side 110 is sealed to the second side 120 along three edge seals 50, 60, 115 of the first side 110 and the second side 120.

In the embodiments of Figs. 2A-2B, the package has a substantially rectangular shape. Those skilled in the art will understand that this form is by way of example only and that other forms of packaging can also be used and adapted to the advantages and benefits of the present invention. The package 100 of Fig. 2A-2B has a lengthwise and a widthwise direction. The at least one edge seal of Fig. 2A-2B includes three edge seals 50, 60, 115: a longitudinal edge seal 115 in the longitudinal direction, a lower edge seal 50 in the width direction, and an upper edge seal 60 in the width direction, opposite the lower edge seal. The longitudinal edge seal 115 is preferably located substantially centrally with respect to the second side 120.

In the examples of Fig. 2A-2B, the polymer sheet is folded in half and sealed lengthwise with the edge seal 115 to form a tube.

The lower edge seal 50 and the upper edge seal 60 both have a seal strength of greater than 30N/15mm, preferably greater than 40N/15mm, more preferably greater than 50N/15mm, and most preferably greater than 60N/15mm. 15mm. The longitudinal edge seal 115 also has a sealing strength above 30N/15mm, preferably above 40N/15mm, more preferably above 50N/15mm, most preferably above 60N/15mm.

The first side 110 and the second side 120 both have a side length Ls between 200mm and

800mm, preferably between 400mm and 700mm, and have a side width probably between 100mm and 500mm, preferably between 300mm and 500mm.

The package 100, after being filled and fully sealed, can hold a load between 3kg and 30kg, preferably between 5kg and 25kg. It is also important that products with sharp edges can still be safely and vacuum packed. It would be detrimental to the packaging of these products if a perforation were to occur through the polymer material, either during the packaging process, the supply chain or during the shelf life of the product. In the case of perforation, the product will be exposed to the environment and therefore susceptible to degradation. To prevent this, the polymer film can have a puncture resistance of greater than 3N, preferably greater than 5N, and even greater than ION.

At least one opening 40, 40' is provided in one of the first side 110 and the second side 120, in the first side 110 in the embodiment of Fig. 2A-2B. The at least one opening 40, 40' is formed by laser cutting to obtain sharp edges on the cutting surface, thereby reducing the risk of material tearing during vacuuming of the package. In another embodiment, at least one opening can be obtained by physically piercing, thermally piercing and/or punching a hole. Furthermore, the at least one opening 40, 40' may comprise an opening with a rounded edge.

The at least one opening 40, 40' may be formed in the polymer film 100 in a sheet or roll form before it is formed into a tube, after it is formed into a tube, or after it is filled with the product. In the most advantageous preferred embodiment, the opening 40, 40' is made when the polymer film 100 is in sheet or roll form.

In Fig. 2A, the at least one opening 40 consists of three circular openings describing an equilateral triangular shape. The opening 40 of Fig. 2A is located in the widthwise direction in the middle of the first side 110 and in the longitudinal direction near the upper edge seal 60. In the preferred embodiment of FIG. 2B, the opening 40' consists of a single oval opening. The opening 40' is located in the center of the first side 110, both widthwise and lengthwise, opposite the longitudinal edge seal 115. This allows for a more even vacuuming of the package. 100. The oval-shaped opening of the at least one opening 40' is oriented in the longitudinal direction of the package 100.

The at least one opening 40' of Fig. 2B has a longest dimension Lo between 1mm and 20mm, preferably between 5mm and 18mm, more preferably between 8mm and 15mm. Also, the at least one opening 40' of Fig. 2B has a shortest dimension wo between 1mm and 10mm, preferably between 1mm and 8mm.

The product packaged in the package 100 comprises particles, preferably foodstuffs such as chocolate drops. It is advisable that the dimensions of the at least one opening 40, 40' are smaller than the dimensions of a particle, i.e. an individual unit, of the particles, so that the product is not evacuated through the vacuum opening or blocks it when extracting air during vacuuming. More specifically, the particles may be formed as a disc shape with a diameter between 28mm and 35mm and a height between 4mm and 8mm. The skilled person will understand that, in general, the at least one opening is so large that the particles cannot pass through the at least one opening during vacuuming.

After vacuuming, at least one opening 40, 40' is closed with at least one closing element 45, 45'. In the embodiment of Figures 2A-2B, the at least one closing element 45, 45' comprises a sticker designed to seal the at least one opening 40, 40'. In another embodiment, at least one valve can be provided at the at least one opening 40, 40' and sealed within the at least one opening 40, 40' using an adhesive or welding to secure it to the polymer film. The valve can be self-closing after vacuuming, but can also be covered with a sticker. The sticker that forms part of at least one closing element 45, 45' is provided with an adhesive layer that faces the package 100, to guarantee the adhesive force of the sticker on the package 100. Preferably, the at least one closing element 45, 45" has a round shape and a diameter of at least 100 mm, to prevent air from being sucked in from at least one opening 40, 40'. Preferably, the sticker for >85, 40' 0% by weight, preferably >90.0% by weight, preferably >95.0% by weight, polyethylene based on the weight of the sticker.

The skilled person will understand that the sticker in at least one closure element 45, 45' is not limited by a particular shape and can be a rectangular sticker 45 as shown in

Fig.2A or a circular sticker as shown in Fig.2B, for example.

Figure 3 shows a flowchart of a method for vacuum packaging particles in a package according to an exemplary embodiment of the present invention. The resulting package is similar to the embodiment of packages shown in Fig. 2A-2B.

The first step S10 of the method involves stretching a tube made of a polymer film with at least one opening. The tube may be provided by a forming and sealing machine adapted to form the polymer film into the shape of a tube from a roll of polymer film, and to seal the formed tube in the longitudinal direction.

This tube is then fed to a subsequent machine that seals and fills the package. Preferably, a VFFS machine is used to form the tube in line prior to a sealing step (for a bottom edge seal and/or a top edge seal of the package) and a package filling step.

The polymer film used is similar to the polymer films shown in Figures 1A-1B. The polymer film is adapted to form the package and comprises an outer film layer and an inner film layer. The outer film layer is a first polyethylene film layer and the inner film layer is a thermally sealable second polyethylene film layer with different thermal properties than the first polyethylene film layer. The tube may be formed with a single polymer film that is folded in half to form opposing portions of the inner film layer, and sealed with a longitudinal longitudinal edge seal.

In the first step S10 of the method, at least one opening can be obtained by physically piercing the polymer film, thermally piercing, cutting, for example by means of laser cutting, and/or by punching a hole in the polymer film. In the embodiment of Fig. 3, the opening can be provided in the polymer film in a sheet or roll form before it is formed into a tube, or after a polymer tube has been obtained from at least one sheet of polymer film. The dimensions of at least one opening are smaller than the dimensions of a particle of the particles.

The second step S11 of the method involves forming a bottom edge seal of the package by sealing opposing portions of the inner film layer. Forming the lower edge seal is performed by locally heating the polymer tube over its entire width at a temperature above the seal initiation temperature of the inner film layer and below the seal initiation temperature of the outer film layer.

In the next step S12, the method includes filling the package with the particles from a top direction. For practical reasons, when the polymer tube is applied in the first step S10, it is laid from a top direction around a substantially cylindrical tube. The polymer tube will then continue along the length of the tube. The second step

S11 is performed by a sealing clamp that follows the end of the pipe, underneath.

After the polymer tube has moved along the tube for a predetermined distance (the length of the package) after step S11, step S12 is performed. The conduit is then used in step S12 to funnel the product from the top direction, which will stack over the formed bottom edge seal. The package can be filled in step S12 with a particle load of between 5kg and 25kg, preferably between 10kg and 20kg.

After filling the package, the method step S13 includes forming an upper edge seal of the package above the filled particulate mass by sealing opposing portions of the inner film layer. To achieve this, the same sealing clamp can be used as in step S11. More specifically, the sealing clamp can simultaneously seal the top edge of the current package and the bottom edge of a subsequent package. In an alternative embodiment, the polymer tube is pre-cut into pieces of a predetermined length (the length of the package) and the top edge seal of the current package and the bottom edge seal of the next package are formed in separate steps. In yet another embodiment, the package is preformed and only the top edge seal needs to be formed after filling the package.

The method then comprises step S15, vacuuming the package through the at least one opening. The vacuuming step S15 can be performed on a substantially horizontally filled package by moving the filled and sealed package from a vertical position to a horizontal position. This distributes the packaged particles more evenly along the length of the package, which simplifies the subsequent handling and palletizing process. In addition, the air contained in the interstices between the individual units (particles) of the particles can be evacuated more easily. A vacuum of at least 600mbar, preferably at least 400mbar, can be achieved during the vacuuming step S15 of the package.

Finally, the method includes closing the opening S16. The step of closing S16 the at least one opening may comprise applying at least one closing element, preferably a sticker, over the at least one opening. In an alternative embodiment, at least one valve can be provided at the opening and sealed within the opening.

The at least one valve may be self-closing upon removal of a machine used for step S15. Those skilled in the art will appreciate that, depending on the embodiment, at least one valve can be sealed in the opening and added to the polymer film in sheet or roll form already, or can be sealed inline in the opening prior to step S10, or inline between step S14 and step S15.

In the embodiment of Fig. 3, in case the polymer tube is provided, after the step of forming S13 the top seal, the method may further include the step of cutting S14 the filled package from the polymer tube to obtain a first filled package under vacuum, and repeating the steps of filling S12 and forming a top seal at S13 to obtain multiple filled packages.

Once filled particle packages have been obtained by vacuum packaging, they are stacked in a final step S20 of the method. Those skilled in the art will understand that this step is optional and not necessarily necessary for forming and filling the package.

The stacking step S20 involves stacking a number of filled packages on a pallet in a layered manner, wherein adjacent filled packages of the stacked number of filled packages are in direct contact with each other. This is made possible by placing the packages horizontally prior to vacuuming through the at least one opening provided on the side of the package.

Preferably, the different layers of packaging on the pallet are separated by non-slip sheets of paper, to improve the overall stability of the load on the pallet. In addition, a PE stretch film can be used to wrap around the stack of filled packages, further stabilizing the load on the pallet. Alternatively, the different layers of packaging can be secured together with glue.

Although the principles of the invention have been set forth above in connection with specific embodiments, it is to be understood that this description is given by way of example only and not as a limitation on the scope of protection defined by the appended claims.

Claims (30)

CONCLUSIONS 1. A package that packs a product under vacuum, preferably a cushion-type package, formed by a polymer film, the polymer film comprising: - an outer film layer (10,107), wherein the outer film layer (10,10) is a first polyethylene film layer ; and - an inner film layer (20.20”), wherein the inner film layer (20.20”) is a thermally sealable second polyethylene film layer with different thermal properties than the first polyethylene film layer; - Wherein the outer film layer (10, 10°) and the inner film layer (20,20') comprise 290.0% by weight of polyethylene with respect to the weight of the first polyethylene film layer and the second polyethylene film layer respectively, wherein the packaging (100 ) is provided with at least one opening (40, 40") on a side thereof, which opening (40, 40") is designed for vacuum packaging and is closed by at least one closing element (45, 45"). The package according to claim 1, wherein the outer film layer (10, 10") and the inner film layer (20, 20") comprise >95.0% by weight, polyethylene with respect to the weight of the first polyethylene film layer and, respectively the second polyethylene film layer. The package according to claim 1 or 2, wherein the outer film layer (10, 10") has a thickness between 8um and 50um, preferably between 10um and 40um, more preferably between 10um and 30um. The package according to any one of the preceding claims, wherein the inner film layer (20, 20") has a thickness between 60um and 150um. The package according to any one of the preceding claims, wherein the outer film layer (10, 10") is a machine direction oriented polyethylene film layer. The packaging according to any one of the preceding claims, wherein the inner film layer (20, 20") is a PE/EVOH/PE, a PE/SiOx, a PE/AIOx, or a metallized PE film layer, preferably a PE/EVOH /PE film layer. The package according to any one of the preceding claims, wherein the polymer film is a laminated film or a co-extruded film. The package according to any one of the preceding claims, further comprising an intermediate film layer (30°) between the outer film layer (10') and the inner film layer (20"), wherein the intermediate film layer (30°) is a third polyethylene film layer, preferably a coextruded PE/EVOH/PE film layer. The package according to the previous claim, wherein the intermediate film layer (30") comprises 285.0% by weight, preferably >90.0% by weight, more preferably >95.0% by weight, polyethylene with respect to the weight of the third polyethylene film layer. The package according to claims 8 or 9, wherein the intermediate film layer (30") has a thickness between 8um and 50um, preferably between 10um and 40um, more preferably between 104m and 30um. The package according to any one of the preceding claims, wherein the at least one opening (40, 40") is formed by laser cutting. The package according to any one of the preceding claims, wherein the at least one opening (40, 40") comprises an opening with a rounded edge, wherein the at least one opening (40, 40") preferably comprises a substantially oval-shaped opening. The package according to any one of the preceding claims, wherein the at least one opening (40') has a longest dimension (L) between 1mm and 20mm, preferably between 5mm and 18mm, more preferably between 8mm and 15mm. The package according to any one of the preceding claims, wherein the at least one opening (40') has a shortest dimension (w) between 1 mm and 10 mm, preferably between 1 mm and 8 mm. The package according to any one of the preceding claims, wherein the at least one closing element (45, 45") comprises a sticker adapted to seal the at least one opening (40, 40"). The package according to any one of the preceding claims, wherein the package (100) has a first side (110) and a second side (120), the first side (110) being sealed to the second side (120) along at least one edge seal of the first and second sides, wherein the at least one opening (40, 40") is provided in one of the first side (110) and the second side (120). The package according to the previous claim, wherein the package has a longitudinal direction and a width direction, and wherein the at least one edge seal is a longitudinal edge seal (115) in the longitudinal direction, a lower edge seal (50) in the width direction, and an upper edge seal (50) in the width direction (60) in the width direction. The package according to the previous claim, wherein the lower edge seal (50) and the upper edge seal (60) both have a seal strength greater than 30N/15mm, preferably greater than 40N/15mm, more preferably greater than 50N/15mm, most preferably greater than 60N/15mm. The packaging according to any of claims 16-18, wherein the first side (110) and the second side (120) both have a side length (Ls) between 200mm and 800mm, preferably between 400mm and 700mm, and a side width (ws ) have between 100mm and 500mm, preferably between 300mm and 500mm. The package according to any one of the preceding claims, wherein the package (100) contains a load between 3kg and 30kg, preferably between 5kg and 25kg. The package according to any one of the preceding claims, wherein the product packaged in the package (100) are particles, preferably from foodstuffs. The package according to any one of the preceding claims, wherein the polymer film has a puncture resistance greater than 3N, preferably greater than 5N, and even greater than ION. 23. A method for packaging particles, preferably foodstuffs, in a package, comprising the steps of: - providing (S10) a tube made of a polymer film with at least one opening (40, 40"), wherein the polymer film is adapted to form the package (100) and comprises an outer film layer (10) and an inner film layer (20), wherein the outer film layer (10) is a first polyethylene film layer and the inner film layer (20) is a thermally sealable second polyethylene film layer has different thermal properties than the first polyethylene film layer, where the outer film layer (10, 10") and the inner film layer (20,20") comprise >90.0 wt% polyethylene with respect to the weight of respectively the first polyethylene film layer and the second polyethylene film layer; - forming (S11) a lower edge seal (50) of the package by sealing opposing portions of the inner film layer (20); - filling (S12) the package (100) with the particles from an upper direction; - forming (S13) an upper edge seal (60) of the package above the filled particles by sealing opposing parts of the inner film layer (20); - optionally, move the packaging from a vertical to a horizontal position; - vacuuming (S15) the package (100) via the at least one opening (40, 40"); - closing (S16) the at least one opening (40, 40"). The method according to the previous claim, wherein the step of vacuuming (S15) is performed on a filled package (100) in a substantially horizontal position. The method according to claim 23 or 24, wherein the method further comprises: - after the step of forming (S13) an upper edge seal (60), cutting (S14) the filled package from the tube to form a first filled package under vacuum, and repeating the steps of filling (S12) and forming (S13) an upper edge seal to obtain a plurality of filled packages (100); - stacking (S20) the multiple filled packages (100) on a pallet in layers, whereby adjacent filled packages of the stacked multiple filled packages (100) are in direct contact. The method according to any one of claims 23 to 25, wherein the step of closing (S16) the at least one opening (40, 40") is providing at least one closing element (45, 45"), preferably a sticker, over at least one opening (40, 40"). The method according to any one of claims 23-26, wherein a negative pressure of at least 600 mbar, preferably at least 400 mbar, is obtained during the step of vacuuming (S15) the package (100). The method according to any of claims 23-27, wherein the at least one opening (40, 40") is provided by cutting, preferably laser cutting. The method according to any one of claims 23-28, wherein the package (100) is filled (S12) with a load of particles between 5 kg and 25 kg, preferably between 10 kg and 20 kg. The method according to any one of claims 23-29, wherein the dimensions of at least one opening are smaller than the dimensions of a particle of the particles.