Patent Grant
12179953
The present invention refers to an apparatus for making packages intended to house one or more products, which may be of various nature, for example food-type products. The invention also refers to a process of making said packages; the packages comprise a plastic support bearing the product which is sealed by a plastic film. The invention may find application for packaging in general, for vacuum packaging or for packaging under controlled atmosphere.
Several different apparatuses and related methods/processes are known for packaging articles like food products positioned on a support and then closed by a closure film.
In particular, packaging systems are known wherein a continuous plastic “bottom” film is unrolled along a machine working direction and subjected to thermoforming thereby defining a continuous precursor body having a plurality of cavities. The cavities in the precursor body receive corresponding products and are sealed by a top plastic film fed parallel to and above the precursor body to make a plurality of packages: the bottom and top plastic films are then cut to create separate finished packages.
In an alternative solution, a cutting station, placed upstream with respect to a thermoforming station, cuts discrete portions from a plastic “bottom” film and moves the film sheets to the thermoforming station; thermoformed supports obtained by the thermoforming station, which may be in the form of trays or flat supports, are then transferred to the subsequent packaging station where each tray or support is closed by a top plastic film.
In yet another alternative, preformed trays are moved on a transfer device to a packaging station. A film roll feeds a top plastic film which moves parallel and above the transfer device: the top plastic film is positioned in the packaging station where it is sealed to the underlying trays.
In the above solutions, the packaging station may be designed to contemporaneously process a plurality of trays or supports positioned according to one or more rows in order to maximize productivity. Consequently, at each packaging cycle, the top plastic film needs to cover one or more rows of trays/supports hosted in the packaging station, which means that, at each packaging cycle, a long piece of top plastic film is pulled and unwind from a supply roll in order to cover and seal all trays/support present in the packaging station. Due to the need of sealing a number of trays/supports in each single cycle (for example packaging machines may have packaging stations hosting two or more rows of trays/support with up to 5 or more trays per row) the length of film to be pulled and positioned above the trays/supports in the packaging station may be very long: for example longer than 1 m.
On the other hand, thin plastic films used as top closure films deviate from a perfectly straight configuration due to inherent inaccuracy in the film manufacturing processes currently adopted, or to other factors such as deformation imposed during winding/unwinding of the film, internal stresses in the film structure, etcetera. As a matter of fact, plastic films used as top closure films may present deviations from a straight configuration of the order of 30 or more mm every 10 linear meters, thus conferring an overall ‘sneaky’ configuration to the plastic film. This results in problems when a relatively long strip of film is pulled from the feed roll and moved to cover one or more rows of tray/supports in the packaging station: in fact, if the pulled film strip presents a ‘snaky’ configuration it may deviate from the supports/trays perimeter and thus be unable to perfectly close all trays. On the other hand, the only way today known to cope with the above problem is to use films much larger than the effective total width of the trays/supports rows to be covered, with evident waste of material and with the need to then trim the excess of film possibly present on the sealed trays/support.
The object of the present invention is to solve at least one of the drawbacks and/or limitations of the prior art.
A first object of the invention is to provide a packaging apparatus and process, which while solving the described drawbacks also guarantees a high production yield.
Another object of the invention is to provide a packaging apparatus and process characterized by high production speed and reduced material scrap.
A further object of this invention is that of providing an apparatus and a process capable of processing a plurality of trays/supports in a same cycle guaranteeing perfect sealing of all trays/supports.
An additional object is that of providing a process and an apparatus for packaging products capable of improving positioning of the top closing film onto the trays or supports.
Furthermore, an ancillary object of the invention is that of offering a packaging apparatus and a packaging process suitable to form ermetically closed packages or packages under vacuum (i.e., vacuum skin packages) or packages under controlled atmosphere.
One or more of the above objects are substantially reached by a packaging process and/or by a packaging apparatus according to one or more of the appended claims.
Aspects of the invention are here below described.
A 1st aspect concerns a process of packaging, the process comprising the following steps:
In a 2nd aspect according to the 1st aspect fixing the selected unrolled portion (7) of the top closure film (3) to the plurality of supports present in the packaging station is achieved by heat sealing the selected portion of the top closure film to the plurality of supports present in the packaging station and in particular positioned at said lower tool loading area (20).
In a 3rd aspect according to any one of the preceding aspects the number of aligned supports (11) in each row of supports (R) is greater than the number of support rows (R) present in the lower tool loading area (20).
In a 4th aspect according to any one of the preceding aspects the support loading area (20) extends more along the alignment direction (D) than perpendicularly to the alignment direction (D).
In a 5th aspect according to any one of the preceding aspects the support loading area (20) extends along the alignment direction (D) at least 1.5 times, preferably at least twice, than perpendicularly to the alignment direction (D).
In a 6th aspect according to any one of the preceding aspects the supports (7) are positioned at the lower tool loading area (20) in correspondence of one or more rows of seats (R′) comprising seats (21) aligned along the alignment direction (D).
In a 7th aspect according to the preceding aspect each row of seats (R′) comprises 3 or more seats (21) thus defining a respective row of supports (R) having 3 or more supports (11).
In a 8th aspect according to any one of the preceding two aspects each row of seats (R′) comprises 5 or more seats (21) thus forming a respective row of supports (R) having 5 or more supports (11).
In a 9th aspect according to any one of the preceding three aspects, wherein the lower tool (18), at the lower tool loading area (20), has a plurality of parallel rows of seats (R′) aligned along the alignment direction (D) and receives said supports (11) positioned according to said rows of supports (R).
In a 10th aspect according to any one of the preceding four aspects the number of seats (21) on each row of seats (R′) is at least twice the number of rows of seats (R′) present in the lower tool loading area (20).
In a 11th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area is of rectangular shape.
In a 12th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has:
In a 13th aspect according to any one of the preceding aspects each one of the supports (11) is a tray having a base wall, a side wall emerging from the base wall and a top flange delimiting a top aperture of the tray and emerging radially from the base wall.
In a 14th aspect according to the preceding aspect the flange has a rectangular external perimeter with two opposite first sides directed parallel to said alignment direction and two opposite second sides directed perpendicular to said alignment direction (D), wherein the width (W) of the selected unrolled portion transferred inside the packaging station and above the supports is at least equal to the measure of one first side times the number of supports present in each row, and wherein length (L) of the selected unrolled portion transferred inside the packaging station and above the supports is at least equal to the measure of one second side times the number of rows of supports present in the packaging station.
In a 15th aspect according to any one of aspects from the 1st to the 12th each one of the supports (11) is a flat support having a rectangular external perimeter with two opposite first sides directed parallel to said alignment direction and two opposite second sides directed perpendicular to said alignment direction (D), wherein the width (W) of the selected unrolled portion transferred inside the packaging station and above the supports is at least equal to the measure of one first side times the number of supports present in each row, and wherein length (L) of the selected unrolled portion transferred inside the packaging station and above the supports is at least equal to the measure of one second side times the number of rows of supports present in the packaging station.
In a 16th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area is a transversal, full-width, elongated strip of the top closure film.
In a 17th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has width (W) significantly greater than the respective length (L), this latter measured perpendicular to said width (W).
In a 18th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has width (W) at least twice the respective length (L), this latter measured perpendicular to said width (W).
In a 19th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has width (W) at least 3 times the respective length (L), this latter measured perpendicular to said width (W).
In a 20th aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has width (W) at least 5 times the respective length (L), this latter measured perpendicular to said width (W).
In a 21st aspect according to any one of the preceding aspects the selected unrolled portion (7) of the top closure film transferred inside the packaging station and above the lower tool loading area has width (W) at least 10 times the respective length (L), this latter measured perpendicular to said width (W).
In a 22nd aspect according to any one of the preceding aspects the process comprises repeating at intervals a packaging cycle comprising at least the following steps:
In a 23rd aspect according to any one of the preceding aspects the process comprises repeating at intervals a packaging cycle comprising at least the following steps:
In a 24th aspect according to any one of the preceding aspects the process comprises a cutting procedure executed at a cutting station (9) operatively interposed between the supplying station (1) and the transfer device (10), wherein the cutting station receives the top closure film and separates from it said selected unrolled portion (7) before it is transferred inside the packaging station (8).
In a 25th aspect according to any the preceding aspect the cutting procedure comprises to transversally separate the selected unrolled portion (7) from the top closure film (3), forming a separated unrolled portion, divided from the rest of the closure film coming from the feed roll, in the form of a unitary strip having the same width (W) of the top closure film.
In a 26th aspect according to any one of the preceding aspects from the 1st to the 24th the cutting procedure comprises to transversally separate said selected unrolled portion (7) from the top closure film (3) and longitudinally divide the closure film at said selected unrolled portion, forming a separated unrolled portion constituted by a plurality of longitudinally separated and transversally adjacent distinct film sheets (7a).
In a 27th aspect according to any one of the preceding three aspects the separated unrolled portion (7) is sized exactly to cover all supports (11) of a same row of supports (R) present in the packaging station (8) and to cover all rows of supports present in the packaging station (8).
In a 28th aspect according to any one of the preceding four aspects the separated unrolled portion (7) once transferred into the sealing station is engaged to the underlying supports (11) present in the lower tool load area (20) such that each one of the supports (11) is heat sealed to a respective part of the separated unrolled portion (7) or to a respective one of the distinct film sheets (7a).
In a 29th aspect according to any one of the preceding aspects the width of the top closure film (3), measured parallel to said unwinding axis (A), and thus the width (W) of each selected unrolled portion (7), is at least 450 mm.
In a 30th aspect according to any one of the preceding aspects the width of the top closure film (3), measured parallel to said unwinding axis (A), and thus the width (W) of each selected unrolled portion (7), is at least at least 600 mm.
In a 31st aspect according to any one of the preceding aspects the width of the top closure film (3), measured parallel to said unwinding axis (A), and thus the width (W) of each selected unrolled portion (7), is at least at least 1000 mm.
In a 32nd aspect according to any one of the preceding aspects the width of the top closure film (3), measured parallel to said unwinding axis (A), and thus the width (W) of each selected unrolled portion (7), is 1200 mm.
In a 33rd aspect according to any one of the preceding aspects the top closure film (3) is a plastic film.
In a 34th aspect according to any one of the preceding aspects the top plastic film (3) is an extruded mono or multilayer plastic film.
In a 35th aspect according to any one of the preceding aspects the top closure film (3) has a thickness comprised between 10 and 200 μm.
In a 36th aspect according to any one of the preceding aspects the step of transferring comprises:
In a 37th aspect according to the preceding aspect the active surface of the transfer body (40) is flat.
In a 38th aspect according to any one of the preceding two aspects wherein the active surface of the transfer body (40) keeps the selected unrolled portion in position under a suction force exerted by sucking air through a plurality of suction holes (41) present on said active surface and connected to a vacuum source (42).
In a 39th aspect according to any one of the preceding three aspects wherein the active surface of the transfer body (40) keeps the selected unrolled portion (7) while moving the transfer body (40) from the cutting station (9) to the packaging station (8) and until releasing under the action of a suction force exerted by sucking air through a plurality of suction holes (41) present on said active surface and connected to a vacuum source (42).
In a 40th aspect according to any one of the preceding aspects wherein transferring comprises grasping the leading edge (7b) of the selected unrolled portion (7) and moving this latter from a pick up zone outside the packaging station into the packaging station and above the lower tool loading area.
In a 41st aspect according to any one of the preceding aspects wherein transferring the unrolled selected portion (7) into the packaging station (8) is effected without grasping opposite longitudinal side borders of said selected unrolled portion.
In a 42nd aspect according to any one of the preceding aspects wherein transferring the unrolled selected portion (7) from the cutting station into the packaging station is effected without grasping opposite longitudinal side borders of said selected unrolled portion.
In a 43rd aspect according to any one of the preceding aspects wherein transferring the unrolled selected portion (7) into the packaging station is effected without using conveying elements such as pincers grasping the longitudinal side borders of said selected unrolled portion.
In a 44th aspect according to any one of the preceding aspects wherein transferring the unrolled selected portion (7) from the cutting station into the packaging station is effected without using conveying elements such as pincers grasping the longitudinal side borders of said selected unrolled portion.
A 45th aspect concerns a packaging apparatus (100) comprising:
In a 46th aspect according to the preceding aspect the lower tool loading area is configured such that the number of supports (11) in each row of supports (R) is greater than the number of rows of supports (R) in the same lower tool loading area.
In a 47th aspect according to any one of the preceding two aspects the support loading area (20) extends more along the alignment direction (D) than perpendicularly to the alignment direction (D).
In a 48th aspect according to any one of the preceding three aspects the lower tool (18), at the lower tool loading area (20), has one or more rows of seats (R′) aligned along the alignment direction (D) and configured for receiving said supports (11) positioned according to said one or more rows of supports (R).
In a 49th aspect according to the preceding aspect each row of seats (R′) comprises 3 or more aligned seats (21).
In a 49th aspect according to the preceding aspect each row of seats (R′) comprises 5 or more, aligned seats (21).
In a 50th aspect according to any one of the preceding three aspects the lower tool (18), at the lower tool loading area (20), has a plurality of parallel rows of seats (R′) aligned along the alignment direction (D) and configured for receiving said supports (11) positioned according to said rows of supports (R); and
In a 51st aspect according to any one of the preceding aspects from the 45th to the 50th the transfer device (10) is configured to:
In a 52nd aspect according to the preceding aspect wherein the transfer device (10) is configured to act on, and transfer above the lower tool loading area (20), one selected unrolled portion (7) of said top closure film (3) having width (W) at least twice the respective length (L).
In a 53rd aspect according to the preceding aspect wherein the transfer device (10) is configured to act on, and transfer above the lower tool loading area (20), one selected unrolled portion (7) of said top closure film (3) having width (W) at least 3 times the respective length (L).
In a 54th aspect according to the preceding aspect wherein the transfer device (10) is configured to act on, and transfer above the lower tool loading area (20), one selected unrolled portion (7) of said top closure film (3) having width (W) at least 5 times the respective length (L).
In a 55th aspect according to the preceding aspect wherein the transfer device (10) is configured to act on, and transfer above the lower tool loading area (20), one selected unrolled portion (7) of said top closure film (3) having width (W) at least 10 times, the respective length (L).
In a 56th aspect according to any one of the preceding aspects from the 45th to the 55th wherein the transfer device (10) is configured to:
In a 57th aspect according to any one of the preceding aspects from the 45th to the 56th wherein the transfer device (10) is configured to:
In a 58th aspect according to any one of the preceding aspects from the 45th to the 57th the packaging apparatus (100) comprises a control unit (50) communicatively connected to the packaging station (8) and to the transfer device (10).
In a 59th aspect according to the preceding aspect the control unit is configured to execute the steps of the process of any one of the aspects from the 1st to the 44th.
In a 60th aspect according to any one of the preceding two aspects the control unit (50) is configured to execute a packaging cycle comprising at least the following steps:
In a 61st aspect according to any one of the preceding aspects from the 45th to the 60th the film supplying station (1) is configured to engage said at least one feed roll (2) for rotation about the respective unwinding axis (A) which is parallel to said predetermined alignment direction (D).
In a 62nd aspect according to any one of the preceding aspects from the 45th to the 61st the packaging apparatus further comprises a cutting station (9) operatively interposed between the film supplying station (1) and the transfer device (10).
In a 63rd aspect according to the preceding aspect the cutting station is communicatively connected to and controlled by the control unit.
In a 64th aspect according to any one of the preceding two aspects the cutting station (9) is configured to transversally separate the selected unrolled portion (7) from the top closure film (3), forming a separated unrolled portion, divided from the rest of the closure film coming from the feed roll, in the form of a unitary strip having the same width (W) of the top closure film (3).
In a 65th aspect according to any one of the preceding aspects 62nd or 63rd the cutting station (9) is configured to transversally separate said selected unrolled portion (7) from the top closure film (3) and longitudinally divide the closure film (3) at said selected unrolled portion (7), forming a separated unrolled portion constituted by a plurality of longitudinally separated and transversally adjacent distinct film sheets (7a).
In a 66th aspect according to any one of the preceding aspects from the 45th to the 65th the film supplying station (1) engages one feed roll (2) providing the top closure film (3) of width (W), measured parallel to said unwinding axis (A), of at least 450 mm.
In a 67th aspect according to any one of the preceding aspects from the 45th to the 66th the film supplying station (1) engages one feed roll (2) providing the top closure film (3) of width (W), measured parallel to said unwinding axis (A), of at least 600 mm.
In a 68th aspect according to any one of the preceding aspects from the 45th to the 67th the film supplying station (1) engages one feed roll (2) providing the top closure film (3) of width (W), measured parallel to said unwinding axis (A), of at least 1000 mm.
In a 69th aspect according to any one of the preceding aspects from the 45th to the 68th the film supplying station (1) engages one feed roll (2) providing the top closure film (3) of width (W), measured parallel to said unwinding axis (A), of above 1200 mm.
In a 70th aspect according to any one of the preceding aspects from the 45th to the 69th the film supplying station (1) engages one feed roll (2) providing the top closure film (3) wherein the top closure film is a plastic film.
In a 71st aspect according to the preceding aspect wherein the top closure film has a thickness comprised between 10 and 200 μm.
In a 72nd aspect according to any one of the preceding aspects from the 62nd to the 71st the transfer device (10) comprises a transfer plate (40), optionally having a plurality of suction holes connected to a vacuum source, configured to move the separated unrolled portion or a/the plurality of distinct film sheets (5) from the cutting station (9) to the packaging station (30).
In a 73rd aspect according to any one of the preceding aspects from the 62nd to the 72nd the transfer device (10) comprises a transfer plate (40), having a plurality of suction holes connected to a vacuum source, configured to move the separated unrolled portion or a/the plurality of distinct film sheets (5) from the cutting station (9) to the packaging station (30).
In a 74th aspect according to any one of the preceding aspects from the 45th to the 73rd the transfer device (10) comprises one or more pincers acting on the leading edge (7b) of the selected unrolled portion from the cutting station (9) to the packaging station (30).
In a 75th aspect according to any one of the preceding aspects from the 45th to the 74th the apparatus (100) has no means for grasping opposite longitudinal side borders of said selected unrolled portion, in particular no conveying elements such as pincers grasping the longitudinal side borders of said selected unrolled portion are present and operate for transferring the unrolled selected portion (7) from the cutting station into the packaging station.
In a 76th aspect according to any one of aspects from the 1st to the 44th the packaging process uses the apparatus according to any one of aspects from the 45th to the 75th.
In a 77th aspect according to any one of aspects from the 45th to the 75th the packaging apparatus (100) is configured to execute the packaging process according to any one of aspects from the 1st to the 44th.
Embodiments and aspects of the invention are described herein below, with reference to the accompanying drawings, which are provided for exemplifying and non-limitative purpose, in which:
It should be noted that in the present detailed description, corresponding parts illustrated in the various figures are indicated with the same reference numerals. The figures could illustrate the object of the invention by means of non-scale representations; therefore, parts and components shown in the figures relating to the object of the invention could only concern schematic representations.
The terms upstream and downstream refer to a direction of advancement of a package—or of a support for making said package—along a predetermined path defined starting from a starting or forming station of a support for said package, through a packaging station and then up to a packaging unloading station.
Although certain aspects of the invention may find application for packaging a product into a packaging solely formed of one or more plastic films, the following description will mainly refer to packaging of a product positioned on a support to which a plastic film is heat sealed. Note the product may be a food product or not.
As used herein support means either a substantially flat element onto which a product is placed, or a container (alternatively referred to as tray) of the type having a base wall, a side wall and a top rim radially emerging from the side wall, the container defining a volume into which the product is positioned.
The trays or supports may have a rectangular shape or any other suitable shape, such as round, square, elliptical etcetera, and may be formed either while the packaging process takes place, e.g. at a thermoforming station of the packaging apparatus, or they may be manufactured beforehand and then fed to the packaging apparatus.
When used herein ‘selected unrolled portion’ refers to a portion of the top closure film which is unrolled from the top closure film feed roll and which extends across the full width of the top closure film. The selected unrolled portion presents same width (measured perpendicular to the direction of flow of the top closure film and thus parallel to the unwinding axis) of the top closure film and length smaller than its width. In general, the selected unrolled portion has the shape of a rectangular strip with the long side being the width and the short side being the length.
The Trays or Supports
The tray or support may be made of a single layer or, preferably, of a multi-layer polymeric material. In case of a single layer material suitable polymers are for instance polystyrene, polypropylene, polyesters, high density polyethylene, poly(lactic acid), PVC and the like, either foamed or solid.
In an option, the tray or support may provided with gas barrier properties. As used herein such term refers to a film or sheet of material which has an oxygen transmission rate of less than 200 cm3/m2-day-bar, less than 150 cm3/m2-day-bar, less than 100 cm3/m2-day-bar as measured according to ASTM D-3985 at 23° C. and 0% relative humidity.
Suitable materials for gas barrier monolayer thermoplastic trays are for instance polyesters, polyamides and the like.
In case the tray or support is made of a multi-layer material, suitable polymers are for instance ethylene homo- and co-polymers, propylene homo- and co-polymers, polyamides, polystyrene, polyesters, poly(lactic acid), PVC and the like. Part of the multi-layer material can be solid and part can be foamed.
For example, the tray or support may comprises at least one layer of a foamed polymeric material chosen from the group consisting of polystyrene, polypropylene, polyesters and the like.
The multi-layer material may be produced either by co-extrusion of all the layers using co-extrusion techniques or by glue- or heat-lamination of, for instance, a rigid foamed or solid substrate with a thin film, usually called “liner”. The thin film may be laminated either on the side of the tray or support in contact with the product P or on the side facing away from the product P or on both sides. In the latter case the films laminated on the two sides of the tray may be the same or different. A layer of an oxygen barrier material, for instance (ethylene-co-vinyl alcohol) copolymer, is optionally present to increase the shelf-life of the packaged product P.
Gas barrier polymers that may be employed for the gas barrier layer are PVDC, EVOH, polyamides, polyesters and blends thereof. The thickness of the gas barrier layer will be set in order to provide the tray with an oxygen transmission rate suitable for the specific packaged product.
The tray or support may also comprise a heat sealable layer. Generally, the heat-sealable layer will be selected among the polyolefins, such as ethylene homo- or co-polymers, propylene homo- or co-polymers, ethylene/vinyl acetate copolymers, ionomers, and the homo- and co-polyesters, e.g. PETG, a glycol-modified polyethylene terephthalate.
Additional layers, such as adhesive layers, to better adhere the gas-barrier layer to the adjacent layers, may be present in the gas barrier material for the tray and are preferably present depending in particular on the specific resins used for the gas barrier layer.
In case of a multilayer material used to form the tray or support, part of this structure may be foamed and part may be un-foamed. For instance, the tray may comprise (from the outermost layer to the innermost food-contact layer) one or more structural layers, typically of a material such as foam polystyrene, foam polyester or foam polypropylene, or a cast sheet of e.g. polypropylene, polystyrene, poly(vinyl chloride), polyester or cardboard; a gas barrier layer and a heat-sealable layer.
The tray or supports may be obtained from a sheet of foamed polymeric material having a film comprising at least one oxygen barrier layer and at least one surface sealing layer laminated onto the side facing the packaged product, so that the surface sealing layer of the film is the food contact layer the tray. A second film, either barrier or non-barrier, may be laminated on the outer surface of the tray or support.
Specific formulations are used for food products which require heating in conventional or microwave oven before consumption. The surface of the container in contact with the product, i.e. the surface involved in the formation of the seal with the lidding film, may comprise a polyester resin. For instance the container can be made of a cardboard coated with a polyester or it can be integrally made of a polyester resin. Examples of suitable containers for the package of the invention are CPET, APET or APET/CPET containers. Such container can be either foamed or not-foamed.
The Film or Film Material Applied to Trays or Supports to Form a Package
Film or film material (also indicated as top film or top closure film) is applied to the tray/support to form a lid onto the tray/support (e.g., for MAP—modified atmosphere packaging) or a skin associated to the tray or support and matching the contour of the product.
The film for skin applications may be made of a flexible multi-layer material comprising at least a first outer heat-sealable layer, an optional gas barrier layer and a second outer heat-resistant layer. The outer heat-sealable layer may comprise a polymer capable of welding to the inner surface of the supports carrying the products to be packaged, such as for instance ethylene homo- or co-polymers, like LDPE, ethylene/alpha-olefin copolymers, ethylene/acrylic acid copolymers, ethylene/methacrylic acid copolymers, and ethylene/vinyl acetate copolymers, ionomers, co-polyesters, e.g. PETG. The optional gas barrier layer preferably comprises oxygen impermeable resins like PVDC, EVOH, polyamides and blends of EVOH and polyamides. The outer heat-resistant layer may be made of ethylene homo- or copolymers, ethylene/cyclic-olefin copolymers, such as ethylene/norbornene copolymers, propylene homo- or co-polymers, ionomers, (co)polyesters, (co)polyamides. The film may also comprise other layers such as adhesive layers or bulk layers to increase thickness of the film and improve its abuse and deep drawn properties. Particularly used bulk layers are ionomers, ethylene/vinyl acetate copolymers, polyamides and polyesters. In all the film layers, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-block agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linking inhibitors, cross-linking enhancers, UV absorbers, odor absorbers, oxygen scavengers, bactericides, antistatic agents and the like additives known to those skilled in the art of packaging films.
One or more layers of the film can be cross-linked to improve the strength of the film and/or its heat resistance. Cross-linking may be achieved by using chemical additives or by subjecting the film layers to an energetic radiation treatment. The films for skin packaging are typically manufactured in order to show low shrink when heated during the packaging cycle. Those films usually shrink less than 15% at 160° C., more frequently lower than 10%, even more frequently lower than 8% in both the longitudinal and transversal direction (ASTM D2732). The films usually have a thickness comprised between 20 microns and 200 microns, more frequently between 40 and 180 microns and even more frequently between 50 microns and 150 microns.
On the other hand, in case the film is used for creating a lid on the tray/support, the film material may be obtained by co-extrusion or lamination processes. Lid films may have a symmetrical or asymmetrical structure and can be monolayer or multilayer. The multilayer films have at least 2, more frequently at least 5, even more frequently at least 7 layers. The total thickness of the film may vary frequently from 3 to 100 micron, in particular from 5 to 50 micron, even more frequently from 10 to 30 micron. The films may be optionally cross-linked. Cross-linking may be carried out by irradiation with high energy electrons at a suitable dosage level as known in the art. The lid films described above may be heat shrinkable or heat-set. The heat shrinkable films typically show free shrink value at 120° C. measured according to ASTM D2732 in the range of from 2 to 80%, more frequently from 5 to 60%, even more frequently from 10 to 40% in both the longitudinal and transverse direction. The heat-set films usually have free shrink values lower than 10% at 120° C., preferably lower than 5% in both the longitudinal and transversal direction (ASTM D 2732). Lid films usually comprise at least a heat sealable layer and an outer skin layer, which is generally made up of heat resistant polymers or polyolefin. The sealing layer typically comprises a heat-sealable polyolefin which in turn comprises a single polyolefin or a blend of two or more polyolefins such as polyethylene or polypropylene or a blend thereof. The sealing layer can be further provided with antifog properties by incorporating one or more antifog additives into its composition or by coating or spraying one or more antifog additives onto the surface of the sealing layer by technical means well known in the art. The sealing layer may further comprise one or more plasticisers. The skin layer may comprises polyesters, polyamides or polyolefin. In some structures, a blend of polyamide and polyester can advantageously be used for the skin layer. In some cases, the lid films comprise a barrier layer. Barrier films typically have an OTR (evaluated at 23° C. and 0% according to ASTM D-3985) below 100 cm3/(m2·day·atm) and more frequently below 80 cm3/(m2·day·atm). The barrier layer is usually made of a thermoplastic resin selected among a saponified or hydrolyzed product of ethylene-vinyl acetate copolymer (EVOH), an amorphous polyamide and a vinyl-vinylidene chloride and their admixtures. Some materials comprise an EVOH barrier layer, sandwiched between two polyamide layers. The skin layer typically comprises polyesters, polyamides or polyolefin.
In some packaging applications, the lid films do not comprise any barrier layer. Such films usually comprise one or more polyolefin are herein defined.
Non-barrier films typically have an OTR (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) from 100 cm3/(m2·day·atm) up to 10000 cm3/(m2·day·atm), more typically up to 6000 cm3/(m2·day·atm).
Peculiar compositions polyester-based are those used for tray lidding of ready-meals packages. For these films, the polyester resins can make up at least 50%, 60%, 70%, 80%, 90% by weight of the film. These films are typically used in combination with polyester-based supports.
For instance the container can be made of a cardboard coated with a polyester or it can be integrally made of a polyester resin. Examples of suitable containers for the package are CPET, APET or APET/CPET containers, either foamed or not-foamed.
Usually, biaxially oriented PET are used as the lid film due to its high thermal stability at standard food heating/cooking temperatures. Often biaxially oriented polyester films are heat-set, i.e. non-heat-shrinkable. To improve the heat-sealability of the PET lidding film to the container a heat-sealable layer of a lower melting material is usually provided on the film. The heat-sealable layer may be coextruded with the PET base layer (as disclosed in EP-A-1,529,797 and WO2007/093495) or it may be solvent- or extrusion-coated over the base film (as disclosed in U.S. Pat. No. 2,762,720 and EP-A-1,252,008).
Particularly in the case of fresh red meat packages, twin lidding film comprising an inner, oxygen-permeable, and an outer, oxygen-impermeable, lidding film are advantageously used. The combination of these two films significantly prevents the meat discoloration also when the packaged meat extends upwardly with respect to the height of the tray walls, which is the most critical situation in barrier packaging of fresh meat.
These films are described for example in EP1848635 and EP0690012, the disclosures of which are herein incorporated by reference.
The lid film can be monolayer. Typical composition of monolayer films comprise polyesters as herein defined and their blends or polyolefins as herein defined and their blends.
In all the film layers herein described, the polymer components may contain appropriate amounts of additives normally included in such compositions. Some of these additives are preferably included in the outer layers or in one of the outer layers, while some others are preferably added to inner layers. These additives include slip and anti-block agents such as talc, waxes, silica, and the like, antioxidants, stabilizers, plasticizers, fillers, pigments and dyes, cross-linking inhibitors, cross-linking enhancers, UV absorbers, odor absorbers, oxygen scavengers, bactericides, antistatic agents, anti-fog agents or compositions, and the like additives known to those skilled in the art of packaging films.
The films suitable for lidding application can advantageously be perforated, in order to allow the packaged food to breath.
Those films may be perforated by using different technologies available in the art, through laser or mechanical means such as rolls provided with several needles.
The number of perforations per unit area of the film and their dimensions affect the gas permeability of the film.
Microperforated films are usually characterized by OTR value (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) from 2500 cm3/(m2·day·atm) up to 1000000 cm3/(m2·day·atm).
Macroperforated films are usually characterized by OTR (evaluated at 23° C. and 0% R.H. according to ASTM D-3985) higher than 1000000 cm3/(m2·day·atm).
Furthermore, the films herein described for lidding applications can be formulated to provide strong or peelable sealing onto the support. A method of measuring the force of a peelable seal, herein referred to as “peel force” is described in ASTM F-88-00. Acceptable peel force values fare in the range from 100 g/25 mm to 850 g/25 mm, from 150 g/25 mm to 800 g/25 mm, from 200 g/25 mm to 700 g/25 mm.
The desired seal strength is achieved specifically designing the tray and the lid formulations.
In general, one or more layers of the lid film can be printed, in order to provide useful information to the consumer, a pleasing image and/or trademark or other advertising information to enhance the retail sale of the packaged product.
The film may be printed by any suitable method, such as rotary screen, gravure or flexographic techniques mas known in the art.
PVDC is any vinylidene chloride copolymers wherein a major amount of the copolymer comprises vinylidene chloride and a minor amount of the copolymer comprises one or more unsaturated monomers copolymerisable therewith, typically vinyl chloride, and alkyl acrylates or methacrylates (e.g. methyl acrylate or methacrylate) and the blends thereof in different proportions. Generally a PVDC barrier layer will contain plasticisers and/or stabilizers as known in the art.
As used herein, the term EVOH includes saponified or hydrolyzed ethylene-vinyl acetate copolymers, and refers to ethylene/vinyl alcohol copolymers having an ethylene comonomer content preferably comprised from about 28 to about 48 mole %, more preferably, from about 32 to about 44 mole % ethylene, and even more preferably, and a saponification degree of at least 85%, preferably at least 90%.
The term “polyamides” as used herein is intended to refer to both homo- and co- or ter-polyamides. This term specifically includes aliphatic polyamides or co-polyamides, e.g., polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 69, polyamide 610, polyamide 612, copolyamide 6/9, copolyamide 6/10, copolyamide 6/12, copolyamide 6/66, copolyamide 6/69, aromatic and partially aromatic polyamides or co-polyamides, such as polyamide 61, polyamide 6I/6T, polyamide MXD6, polyamide MXD6/MXDI, and blends thereof.
As used herein, the term “copolymer” refers to a polymer derived from two or more types of monomers, and includes terpolymers. Ethylene homopolymers include high density polyethylene (HDPE) and low density polyethylene (LDPE). Ethylene copolymers include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers. Ethylene/alpha-olefin copolymers generally include copolymers of ethylene and one or more comonomers selected from alpha-olefins having from 3 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like.
Ethylene/alpha-olefin copolymers generally have a density in the range of from about 0.86 to about 0.94 g/cm3. The term linear low density polyethylene (LLDPE) is generally understood to include that group of ethylene/alpha-olefin copolymers which fall into the density range of about 0.915 to about 0.94 g/cm3 and particularly about 0.915 to about 0.925 g/cm3. Sometimes linear polyethylene in the density range from about 0.926 to about 0.94 g/cm3 is referred to as linear medium density polyethylene (LMDPE). Lower density ethylene/alpha-olefin copolymers may be referred to as very low density polyethylene (VLDPE) and ultra-low density polyethylene (ULDPE). Ethylene/alpha-olefin copolymers may be obtained by either heterogeneous or homogeneous polymerization processes.
Another useful ethylene copolymer is an ethylene/unsaturated ester copolymer, which is the copolymer of ethylene and one or more unsaturated ester monomers. Useful unsaturated esters include vinyl esters of aliphatic carboxylic acids, where the esters have from 4 to 12 carbon atoms, such as vinyl acetate, and alkyl esters of acrylic or methacrylic acid, where the esters have from 4 to 12 carbon atoms.
Ionomers are copolymers of an ethylene and an unsaturated monocarboxylic acid having the carboxylic acid neutralized by a metal ion, such as zinc or, preferably, sodium.
Useful propylene copolymers include propylene/ethylene copolymers, which are copolymers of propylene and ethylene having a majority weight percent content of propylene, and propylene/ethylene/butene terpolymers, which are copolymers of propylene, ethylene and 1-butene.
As used herein, the term “polyolefin” refers to any polymerized olefin, which can be linear, branched, cyclic, aliphatic, aromatic, substituted, or unsubstituted. More specifically, included in the term polyolefin are homo-polymers of olefin, co-polymers of olefin, co-polymers of an olefin and an non-olefinic co-monomer co-polymerizable with the olefin, such as vinyl monomers, modified polymers thereof, and the like. Specific examples include polyethylene homo-polymer, polypropylene homo-polymer, polybutene homo-polymer, ethylene-alpha-olefin co-polymer, propylene-alpha-olefin co-polymer, butene-alpha-olefin co-polymer, ethylene-unsaturated ester co-polymer, ethylene-unsaturated acid co-polymer, (e.g. ethylene-ethyl acrylate co-polymer, ethylene-butyl acrylate co-polymer, ethylene-methyl acrylate co-polymer, ethylene-acrylic acid co-polymer, and ethylene-methacrylic acid co-polymer), ethylene-vinyl acetate copolymer, ionomer resin, polymethylpentene, etc.
The term “polyester” is used herein to refer to both homo- and co-polyesters, wherein homo-polyesters are defined as polymers obtained from the condensation of one dicarboxylic acid with one diol and co-polyesters are defined as polymers obtained from the condensation of one or more dicarboxylic acids with one or more diols. Suitable polyester resins are, for instance, polyesters of ethylene glycol and terephthalic acid, i.e. poly(ethylene terephthalate) (PET). Preference is given to polyesters which contain ethylene units and include, based on the dicarboxylate units, at least 90 mol %, more preferably at least 95 mol %, of terephthalate units. The remaining monomer units are selected from other dicarboxylic acids or diols. Suitable other aromatic dicarboxylic acids are preferably isophthalic acid, phthalic acid, 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid. Of the cycloaliphatic dicarboxylic acids, mention should be made of cyclohexanedicarboxylic acids (in particular cyclohexane-1,4-dicarboxylic acid). Of the aliphatic dicarboxylic acids, the (C3-Ci9)alkanedioic acids are particularly suitable, in particular succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable diols are, for example aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2,2-dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol, optionally heteroatom-containing diols having one or more rings.
Co-polyester resins derived from one or more dicarboxylic acid(s) or their lower alkyl (up to 14 carbon atoms) diesters with one or more glycol(s), particularly an aliphatic or cycloaliphatic glycol may also be used as the polyester resins for the base film.
Suitable dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, or 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, adipic acid, azelaic acid, suberic acid or pimelic acid. Suitable glycol(s) include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,5-pentane diol, 2,2-dimethyl-1,3-propane diol, neopentyl glycol and 1,6-hexane diol, and cycloaliphatic diols such as 1,4-cyclohexanedimethanol and 1,4-cyclohexane diol. Examples of such copolyesters are (i) copolyesters of azelaic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; (ii) copolyesters of adipic acid and terephthalic acid with an aliphatic glycol, preferably ethylene glycol; and (iii) copolyesters of sebacic acid and terephthalic acid with an aliphatic glycol, preferably butylene glycol; (iv) co-polyesters of ethylene glycol, terephthalic acid and isophthalic acid. Suitable amorphous co-polyesters are those derived from an aliphatic diol and a cycloaliphatic diol with one or more, dicarboxylic acid(s), preferably an aromatic dicarboxylic acid. Typical amorphous copolyesters include co-polyesters of terephthalic acid with an aliphatic diol and a cycloaliphatic diol, especially ethylene glycol and 1,4-cyclohexanedimethanol.
Product
The term product P refers to an article or a composite of articles of any kind. For example, the product may be of a foodstuff type and be in the solid, liquid or gel state, i.e. in the form of two or more of the aforementioned aggregation states.
In the food sector, the product can include: meat, fish, cheese, treated meats, prepared and frozen meals of various kinds.
Control Unit
The packaging apparatus described and claimed herein may include one or more control units, designed to control the operations performed by the apparatus. The control unit can evidently be only one or be formed by a plurality of distinct control units according to the design choices and operational needs.
The term control unit means an electronic component which can comprise at least one of: a digital processor (for example comprising at least one selected in the group between: CPU, GPU, GPGPU), a memory (or memories), an analog circuit, or a combination of one or more digital processing units with one or more analog circuits. The control unit can be “configured” or “programmed” to perform some steps: this may be done in practice by any means that allows you to configure or program the control unit. For example, in the case of a control unit comprising one or more CPUs and one or more memories, one or more programs can be stored in appropriate memory banks connected to the CPU or to the CPUs; the program or programs contain instructions which, when executed by the CPU or the CPUs, program or configure the control unit to perform the operations described in relation to the control unit. Alternatively, if the control unit is or includes analog circuitry, then the control unit circuit may be designed to include configured circuitry in use to process electrical signals so as to perform the steps related to control unit. The control unit may comprise one or more digital units, for example of the microprocessor type, or one or more analog units, or a suitable combination of digital and analog units; the control unit can be configured to coordinate all the actions necessary for executing an instruction and instruction sets.
Actuator
The term actuator means any device capable of causing movement on a body, for example behind the control unit (reception by the actuator of a command sent by the control unit). The actuator can be of an electric, pneumatic, mechanical (for example with a spring) type, or of another type.
With reference to the attached figures it is described a packaging apparatus 100, which comprises a film supplying station 1 presenting a feed roll 2 configured to turn around a respective unwinding axis A to unroll consecutive portions of a top closure film 3.
In accordance with an aspect, the width W of the top closure film 3, measured parallel to the unwinding axis A is at least 450 mm, optionally at least 600 mm, more optionally at least 1000 mm, even more optionally above 1200 mm.
In term of materials, the top closure film is a plastic film, in particular an extruded mono or multilayer plastic film as disclosed in the above dedicated section and may have a thickness comprised between 10 and 200 μm.
According to a preferred configuration, the axis of rotation A of the feed roll 2 is arranged horizontally, in particular parallel to the ground. The supplying station 1 may have an electric motor 4 connected to the feed roll 2 and configured to put into rotation the feed roll 2 around the unwinding axis A, in order to unroll, in a controlled manner, subsequent portions of plastic film 3. The electric motor 4 may be connected to the feed roll 2 through a gear train, in order to reduce the angular speed of the motor 4 and increase the applied torque. Of course, it is not excluded that the feed roll 2 may also not be motorized, and for example either be free to rotate or be braked, for example under the action of a friction brake. The top closure film 3 is progressively unrolled and preferably moved about a number of rollers 5 having the task to impose a prescribed path to the film 3 and to maintain a proper film tension. The unrolled portions of top closure film are driven, e.g. via conventional means such as motorized rollers or pincers, to a film pick up zone 6 where, at each packaging cycle, a selected unrolled portion 7 of the top closure film 3 is picked up and transferred inside a packaging station 8 of the apparatus 100. At the pick-up zone 6, in accordance with certain embodiments for example shown in
In general, the apparatus comprises a transfer device 10 (including one single transport device or a plurality of cooperating transport devices), which is responsible for picking a selected unrolled portion of the top closure film either from the cutting station (see examples of
In this connection, the apparatus 100 comprises a support feed station 12 where empty supports 11 are loaded on a first conveyor 13, for example a conveyor belt onto which the supports 11 may be located or a conveyor provided with a sliding surface receiving the supports and cross pieces pushing the supports, or a conveyor having a top side provide with appropriately shaped seats for receiving the supports, or a conveyor of yet another nature. The support feed station 12 may include a support dispenser automatically depositing supports in the appropriate location of the first conveyor or it may simply comprise one or more posts where operators manually load the supports 11. Downstream the support feed station 12, a product loading station 15 operates where either one or more operators provide for loading of the products P in the respective supports 11 positioned on the first conveyor or where one or more automated product dispensing devices deliver one or more products or product dosages P into or above each one of the supports travelling on the first conveyor 13. The first conveyor 13 may be designed to transport the product loaded supports 11 inside the packaging station 8 or, alternatively, an appropriate transfer mechanism 17 operates between the downstream end 13a of the first conveyor 13 and the packaging station 8, in order to pick from the first conveyor 13 one or more arriving product loaded supports 11 and move them in an appropriate location inside the packaging station 8 where the product loaded supports will receive the top closure film 3 and form closed packages. The transfer mechanism 17 may for example include two side bars operative on opposite sides of a row of supports. The opposite bar may present shaped cavities facing the supports to receive the sides of the supports: the bars may be actuated back and forth from the downstream end of the conveyor to inside of the packaging station and vice-versa in order to properly load this the packaging station with an adequate number of supports at each packaging cycle. Alternatively, the transfer mechanism may include robotized arms which pick the supports and displace them in the appropriate location inside the packaging station. Other transfer systems may however be envisaged without departing from the scope of the present disclosure. As shown in the drawings, the packaging station 8 comprises a lower tool 18 and an upper tool 19 cooperating with the lower tool: the supports 11 are positioned at a lower tool loading area 20 which is designed to receive the supports 11 served either by the first conveyor 13 of by the transfer mechanism 17. In accordance with one aspect, the supports 11 are positioned in the lower tool loading area 20 according to one or more parallel rows of supports (each row of supports is indicated with R in the attached drawings): each row R of supports includes a plurality of supports aligned along a predetermined alignment direction D, while the number of aligned supports 11 in each row R of supports is greater than the number of rows R of supports in the lower tool loading area 20. For example the lower tool loading area 20 may be designed to receive one row of 3 supports, or one row with 4 or more supports (see
Again with reference to the drawings, and as already mentioned, the lower tool loading area 20 has a plurality of parallel rows R′ of seats 21 aligned along the alignment direction D: each one of the supports 11 is positioned in one respective seat 21 thus forming rows of aligned supports; the seats 21 may for example be dedicated areas on the top side of the lower tool, or indents in the top side of the lower tool counter-shaped to the support perimeter of the support each seat needs to receive. The top closure film is unrolled from the feed roll 2 and moved to the pick-up zone 6 where the selected unrolled portion 7 arrives and is taken by the transfer device 10, which acts on the selected unrolled portion 7 of the top closure film and brings it inside the packaging station 8. Basically, at each packaging cycle, each selected unrolled portion 7 is therefore transported by the transfer device 10 inside the packaging station 8 in order to then close a plurality of product loaded supports positioned inside the same packaging station. The selected unrolled portion 7 of the top closure film is transferred inside the packaging station 8 and positioned above the lower tool loading area 20, with the width W of each unrolled portion aligned to the alignment direction D of the rows R and R′ (respectively of supports and seats) in the lower tool loading area 20.
In practice, the selected the selected unrolled portion 7 of the top closure film transferred inside the packaging station 8 and above the lower tool loading area 20 is a plastic strip of rectangular shape and has width W sufficient to cover the extension along the alignment direction D of all supports 11 present in the packaging station: said in other words the selected unrolled portion 7 is a widthwise extending strip of the top closure film 3 which is longer in width than in length and which is moved onto the one or more rows of supports 11 with its width W aligned with the direction of alignment D of the row(s) of supports/seats.
The length L of each selected unrolled portion 7 transported inside the packaging station 8 (note the length L is measured perpendicular to the width W of the same selected unrolled portion) is sufficient to cover the extension, perpendicular to said alignment direction D of the lower tool loading area 20 and thus of all supports present in the packaging station. In the embodiments shown it is also to be noted that the film supplying station 1 engages in rotation the feed roll 2 about the respective unwinding axis A which is parallel to the predetermined alignment direction D.
In an embodiment, each one of the supports 11 may be in the form of a tray (see
Although the attached figures show supports 11 in the form of trays with lateral wall and flange, the supports 11 may alternatively be flat. In case of flat supports, each support 11 may have (analogously to the external perimeter of the flange described above) a rectangular external perimeter with two opposite first sides and two opposite second sides meeting the first sides at corner regions of the flat support: in this case, the supports are positioned in the packaging station with the two opposite first sides directed parallel to the alignment direction D and with the two opposite second sides directed perpendicular to the alignment direction D. The width W of the selected unrolled portion transferred inside the packaging station and above the supports is at least equal to the measure of one first side (of the support external perimeter) multiplied by the number of supports present in each row, so as to cover the extension of the supports positioned in the lower tool loading area (see e.g.
An aspect of the invention provides that the selected unrolled portion 7 of the top closure film 3 transferred inside the packaging station and above the lower tool loading area 20 is a transversal, full-width, elongated strip of the top closure film. In particular, the selected unrolled portion 7 of the top closure film 3 transferred inside the packaging station 8 has width W significantly greater than the respective length L (measured perpendicular to said width W). For example, the width W of each selected unrolled portion of the top closure film transferred inside the packaging station may be at least twice or 3 times, or at least 5 times, or at least 10 times the respective length L. In practice, using relatively large width feed rolls 2 and thus relatively large width top closure films 3, it is possible with the width W of each selected portion 7 to cover the longitudinal extension (along direction D) of the whole lower tool loading area 20 (or the extension of row(s) of supports), thus being able at each packaging cycle to use a relatively short length of top closure film thereby solving in a simple manner all the drawbacks of the prior art.
Going in further detail, the apparatus and process according to aspect of the invention provide for repeating at intervals a packaging cycle comprising at least the following steps. The apparatus has in this regard a control unit 50 configured to execute the packaging cycle and at this purpose connected with the packaging station 8, the transfer device 10, and the other components described above. The packaging cycle comprises configuring the packaging station 8 in an open configuration, where the upper and lower tools 18 and 19 are spaced apart the one from the other, and with the packaging station in the open configuration positioning the supports 11, with at least a product loaded thereon, in the packaging station. Again with the packaging station in the open configuration the unrolled portion 7 is transferred into the packaging station 8 and above the lower tool loading area 20.
As discussed above, these steps may be executed under the control of the control unit 50 which may appropriately coordinate one or more actuators 30 acting on the packaging station to bring it in the open configuration, the first conveyor 13 and/or the transfer mechanism 17 to move the product loaded supports 11 in position in the lower tool loading area 20, and the above described transfer device 10 to move the selected unrolled portion 7 in the desired position above the product loaded supports.
Then, the packaging cycle provides for configuring the packaging station 8 in a closed configuration, wherein the upper and lower tools 18 and 19 are approached to each other. With the packaging station in the closed configuration, the top closure film 3 is fixed to the supports, in the selected unrolled portion 7 of the top closure film is heat sealed to the supports 11. As discussed above, these step may be executed under the control of the control unit 50, which may appropriately command a heater 31 present inside the packaging station (typically on the upper tool) to heat at least a peripheral band of the selected unrolled portion and to bring it against the underlying supports 11 in order to achieve heat sealing between the two.
In accordance with one possible variant of the invention, the apparatus and process may provide for a cutting procedure (see for example
The cutting station 9, which is also connected and governed by the control unit 50 in coordination with the other parts of the apparatus described above, may transversally separate the selected unrolled portion 7 from the top closure film forming a single unitary separated unrolled portion, which is divided from the rest of the closure film 3 extending upstream the separated unrolled portion and coming from the feed roll 2. The separated unrolled portion 7 is in the form of a unitary strip having the same width W of the top closure film and a length L sensibly smaller than its width W. Alternatively, the cutting station 9 may be configured to both transversally separate said selected unrolled portion 7 from the top closure film and to also longitudinally divide the closure film 3 in correspondence of the same selected unrolled portion 7. In this way the separated unrolled portion 7 is divided from the rest of the top closure film 3 (which remains connected to the feed roll 2) and is constituted by a plurality of longitudinally separated and transversally adjacent distinct film sheets 7a (see
The separated unrolled portion 7 (see
Going now back to the transfer of the selected unrolled portion 7 into the packaging station, it is noted that the transfer device 10 used for effecting the transfer of the selected film portion 7 from the pick-up zone 6 to the packaging station 8 may comprise a transfer body 40, for example in the form of a plate or in any case of a relatively small thickness body, able to travel back and forth between the cutting station and the packaging station. The step of transferring the selected unrolled portion 7, after separation of this latter from the rest of the top closure film by the cutting station 9, provides for positioning the selected unrolled portion on a continuous active surface 40a of the transfer body: in the examples shown the active surface 40a is a top surface of the transfer body 40 which may be flat, slightly convex or slightly concave, and which keeps the selected unrolled portion 7 in position (also during the transfer displacement) under the constant action of a suction force exerted by sucking air through a plurality of suction holes 41 present on the same active surface 40a and connected to a vacuum source 42, this latter being controlled by the mentioned control unit 50. Then, with the packaging station 8 in the open configuration, the transferring step of the process provides for moving the transfer body 40 and thus the selected unrolled portion 7 (which has been just severed from the rest of the top closure film 3) from the cutting station 9 to the packaging station 8, underneath the upper tool 19, and for releasing the selected unrolled portion from the active surface of the transfer body, once the transfer body is just below and in proximity of the upper tool. The release may be controlled by the control unit 50 which is configured to command the vacuum source 42 to stop sucking air from the suction holes 41 or which may vent the suction holes 41 to the atmosphere by action of an appropriate valve system 43. The unrolled portion released by the transfer body 40 is then captured by a lower surface 19a of the upper tool 19, which may also be provided with a respective number of suction holes 19b connected to a vacuum source (which may be the same vacuum source 42 or another vacuum source 45) under the control of the control unit. At this point the transfer body 10 may be controlled to return to the cutting station 9. The described motion of the transfer body is controlled by the control unit commanding one or more actuators 46 acting on the transfer body 10 and controllably connected with the control unit. The control unit 10 is configured to synchronize the action by the cutting unit, the intervention of the vacuum sources, the opening/closing of the packaging station, the movement of the transfer body, the movement of the first conveyor and of the transfer mechanism, such as the apparatus 100 performs the described steps in the appropriate sequence as described without interference among the various moving parts.
In accordance with an alternative solution, the selected unrolled portion 7 is not transversally severed and separated from the rest of the top closing film 3 before being transferred into the packaging station 8. In this case there is no cutting unit between the film supply assembly 1 and the packaging station 8. Of course the transferring of the selected unrolled portion may take place as above described. On the other hand, in accordance with an alternative, which is for example shown in
In an auxiliary yet particularly advantageous aspect, the step of transferring the unrolled selected portion into the packaging station 8 is effected without grasping opposite longitudinal side borders of the selected unrolled portion: in other words, the selected unrolled portion is either transferred using the transfer body 40 or using the travelling pincers 46 described above: this means that there are no conveying elements such as pincers, or rollers or other means touching or grasping the longitudinal side borders of said selected unrolled portion. This not only avoids to damage the top closure film side borders, but saves a relatively large quantity of top closure film material because any means intervening on the side borders necessarily takes a band on each side of the top closure film which then cannot be used for closing the supports.
Once the packaging cycle is finished and the supports 11 have been closed by the selected unrolled portions of the closure film 3, the packaging station 8 moves to the open configuration and a further transfer mechanism 48 may extract the packaged products PP and move them onto a second conveyor 49 which may be opposite to the first conveyor 13 (as shown in the figures) or which may travel orthogonal to the first conveyor. In case of need, a package severing station 51 comprising one or more blades 52 may operate downstream the packaging station 8 to separate the packaged products the one from the other.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20167364 | Mar 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/057633 | 3/24/2021 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/197978 | 10/7/2021 | WO | A |
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| 20230132274 A1 | Apr 2023 | US |
