Heat shrinkage apparatus and device for packaging, and packaging line and process using the same

Abstract

A heat-shrinking device (1) and apparatus (30) are described, which are configured to heat-shrink selected portions of a container (100) (such as a bag or pouch) made of heat-shrinkable plastic film. The described device and apparatus are configured to selectively heat-shrink the main portion of the container in which a product is contained, or the end portion of the same container. A packaging production line including one or more of the heat-shrinking devices (1) and apparatus (30), and optionally including a vacuum station, is also described. Furthermore, the process for heat-shrinking selected portions of the container (100) and the associated packaging process are described.

Description

Technical Field

[0001] This invention relates to heat shrink equipment and / or heat shrink apparatus for packaging. It also relates to heat shrink processes used in the packaging field. The heat shrink equipment, apparatus, and processes described and claimed herein can be used to heat shrink packaging bags or pouches, or other containers made of or comprising heat shrinkable plastic film materials; said containers, such as bags or pouches, are intended to contain products, such as food products. The invention also relates to packaging processes and packaging production lines using heat shrinkable plastic film materials. In particular, packaging production lines and packaging processes can use the mentioned shrink equipment and / or heat shrink apparatus to manufacture packaging made of or comprising heat shrinkable plastic film materials. The invention can have applications forming packaging in which most of the gas inside the packaging has been vented. In possible variations, the invention can find applications in vacuum packaging. Background Technology

[0002] In the food packaging industry, plastic film is used to form packaging. Plastic film wraps and protects products, and also allows consumers to see the product and thus visually assess its characteristics, such as size, shape, and quality. Plastic packaging used in food packaging often consists of containers in the form of bags or pouches made of plastic material, into which products such as food are inserted. The plastic containers are then sealed.

[0003] In the above context, heat-shrinkable plastic film materials have been widely used because of their ability to provide a durable shell for products, while typically reducing the amount of plastic material required to form the packaging, and thus reducing waste when the packaging needs to be disposed of after perforation.

[0004] On the other hand, known packaging processes and systems that use heat-shrinkable plastic film materials to wrap products often result in packaging that lacks aesthetic appeal and / or does not allow for the acceptance of printed materials.

[0005] Furthermore, known processes and systems using heat-shrinkable materials are often complex to implement and require additional operations, such as puncturing and then sealing the treated packaging to expel any gases that may be contained within the packaging during shrinkage.

[0006] In addition, known shrink-wrap techniques often use water to shrink the packaging, which inherently requires very complex and bulky equipment.

[0007] Additionally, known shrinkage equipment and processes cannot shrink selected portions of the treated packaging.

[0008] Additionally, known systems and processes, particularly those using shrinkable plastic wrapping, do not provide efficient solutions for creating easy-open features on packaging, thus resulting in complex solutions or the production of packaging that may be difficult to open.

[0009] Finally, known systems and processes, especially those using shrinkable plastic wrap, do not offer efficient solutions for automating the application of labels to packaging. Summary of the Invention

[0010] The purpose of this invention

[0011] The object of this invention is to overcome one or more of the disadvantages and / or limitations of the prior art described above. Auxiliary objectives of this invention are indicated below.

[0012] The purpose of this invention is to provide a new heat shrinking device and / or a new heat shrinking apparatus and a simplified design process for efficiently shrinking films of packaging in the process of forming, such as bags or pouches or other containers.

[0013] Another object of the present invention is to provide a new heat shrinking device and / or a new heat shrinking apparatus and / or a new heat shrinking process that can efficiently shrink packaging in formation, thereby avoiding the need for additional operations, such as puncturing the film.

[0014] Another objective is to provide a new heat shrinking device and / or a new heat shrinking apparatus and / or a new heat shrinking process suitable for handling and heat shrinking selected portions of a given package.

[0015] An additional object of the present invention is to make new heat shrinking equipment and / or new heat shrinking devices and / or new heat shrinking processes available, which are capable of efficiently venting at least a portion of the gas from inside the container being processed.

[0016] Another object of the present invention is to provide a new heat shrinking device and / or a new heat shrinking apparatus and / or a new heat shrinking process, which can be combined with equipment / processes for vacuuming packaging in formation, thereby creating a streamlined packaging production line.

[0017] Another object of the present invention is to implement new shrink equipment and / or new heat shrink devices and processes in a highly efficient manner in packaging production lines and packaging processes.

[0018] Furthermore, the aim is to provide a packaging production line and process that can use a reduced amount of plastic to form packages, for example, in the form of plastic bags or pouches, while ensuring efficient and robust packaging.

[0019] Another object of the present invention is a packaging production line and process that can form packaging with a simple and cost-effective structure.

[0020] An additional objective is to provide a packaging production line and process capable of producing packaging with improved aesthetic properties and providing a generally smooth surface suitable for carrying printed materials, pictures, images, and the like.

[0021] Furthermore, the auxiliary objective is to provide a packaging production line and process in which the application of labels is facilitated and automated.

[0022] Finally, another auxiliary objective is to provide a packaging production line and process configured to form an easy-open feature on the packaging. Summary of the Invention

[0024] One or more of the above objectives are substantially achieved by heat shrinking equipment, heat shrinking apparatus, and / or heat shrinking process according to any of the appended corresponding claims. One or more of the above objectives are also achieved by packaging production lines and packaging processes according to one or more of the accompanying drawings.

[0025] The various aspects of the present invention are disclosed below.

[0026] The first aspect relates to a heat-shrinking apparatus configured for processing containers made of or comprising heat-shrinkable plastic film, the containers having a main portion therein for containing a product, an end portion having at least one orifice allowing gas to escape from the container, and an intermediate portion connecting the main portion and the end portion.

[0027] The shrinking device includes:

[0028] - An inlet used to receive containers to be processed.

[0029] - An outlet used to deliver the processed containers.

[0030] - A heat treatment zone between the inlet and outlet, configured as the main part of the container to be heat-shrink processed.

[0031] - A heat protection zone extends adjacent to the heat treatment zone and is configured to receive the end portion of each container.

[0032] In the second aspect according to the first aspect, the heat protection zone is connected to the heat treatment zone via one or more openings extending between the heat treatment zone and the heat protection zone.

[0033] In a third aspect according to the second aspect, the one or more openings include a longitudinal opening extending along the heat treatment zone and configured to receive at least the middle portion of each processed container, such that during operation of the heat shrink apparatus, the main portion of each processed container is received in the heat treatment zone while the end portions of each processed container remain outside the heat treatment zone, wherein the middle portion of each container passes through the longitudinal opening; or

[0034] The one or more openings include a plurality of discrete openings formed along the heat treatment zone, and each opening is configured to receive at least the middle portion of the corresponding processed container, such that during operation of the heat shrinking device, the main portion of each processed container is received in the heat treatment zone while the end portion of each processed container remains outside the heat treatment zone, wherein the middle portion of each container passes through the corresponding discrete opening.

[0035] In the fourth aspect according to any of the foregoing aspects, the device is configured to maintain the heat treatment zone at the shrinkage temperature and the heat protection zone at a temperature below the shrinkage temperature, optionally at a temperature at least 30°C below the shrinkage temperature, and more optionally at a temperature at least 50°C below the shrinkage temperature.

[0036] In the fifth aspect according to any of the foregoing aspects, the heat treatment zone includes at least one heater, which is configured to maintain the heat treatment zone at a shrinkage temperature above 130°C, optionally between 130°C and 180°C during operation of the equipment.

[0037] In the sixth aspect according to any of the foregoing aspects, the heat treatment zone includes a plurality of independently controllable heaters, optionally from 2 to 5 independently controllable heaters, said plurality of independently controllable heaters being distributed along the heat treatment zone and defining corresponding plurality of independently thermally controllable successive longitudinal sections.

[0038] In a seventh aspect according to either the fifth or sixth aspect, the heat treatment zone includes one or more temperature sensors and a control unit communicatively connected to the one or more temperature sensors and one or more heaters, wherein the control unit is configured to:

[0039] - Receive temperature signals from each of the one or more temperature sensors, and

[0040] - Control one or more heaters based on the one or more temperature signals and one or more reference values.

[0041] In the eighth aspect according to the fifth, sixth, or seventh aspect, the heater includes a heat source and a fan that blows air toward the heat source.

[0042] In a sub-aspect of this aspect, each heater is configured to direct hot air in the heat treatment zone, for example, via appropriate channels leading to nozzles distributed on the top portion and one or more sides of the heat treatment zone, thereby directing the hot air from above and from one or more sides toward the container being treated.

[0043] In aspect 9 according to any of the foregoing aspects, during the operation of the equipment, the thermal protection zone is configured to be maintained at a temperature below 100°C, particularly below 90°C.

[0044] According to the 10th aspect of any of the foregoing aspects, one or more thermal insulators are positioned at the periphery of the heat treatment zone, and said thermal insulators include at least one thermal insulating wall between the heat protection zone and the heat treatment zone.

[0045] In a sub-aspect of this aspect, at least one thermal insulation wall defines one or more openings between the thermal protection zone and the heat treatment zone.

[0046] In the 11th aspect according to any of the foregoing aspects, the thermal protection zone includes a cooling structure defining an elongated seat, optionally in the form of an elongated flat channel, configured to receive the end portion of each container and having a proximal side terminating at the one or more longitudinal openings.

[0047] In either of the 11th and 10th aspects, the thermally insulating wall is located between the cooling structure and the heat treatment zone.

[0048] In the 12th aspect according to the preceding aspect, the thermal protection zone includes at least one active cooler configured to act on the cooling structure during operation of the equipment to keep the elongated seat of the thermal protection zone at a temperature at least 30°C below the contraction temperature, and more optionally at a temperature at least 50°C below the contraction temperature.

[0049] Optionally, the thermal protection structure includes multiple coolers, more preferably from 2 to 5 coolers, which are distributed along the thermal protection zone and are independently controllable.

[0050] In the 13th aspect according to the 12th aspect, each active cooler is configured to cool at least one cooling structure.

[0051] In the 14th aspect according to the 12th or 13th aspect, each active cooler includes a cooling fan and / or a liquid cooling system, the cooling fan being configured to blow air toward the cooling structure, the liquid cooling system having a coolant circuit for coolant circulating inside or adjacent to the cooling structure, and a cold source associated with the coolant circuit.

[0052] In a 15th aspect according to aspect 12, 13, or 14, the device includes one or more auxiliary temperature sensors operating in a thermal protection zone and a control unit communicatively connected to the one or more auxiliary temperature sensors and one or more active coolers, wherein the control unit is configured to:

[0053] - Receive auxiliary temperature signals from each of the one or more auxiliary temperature sensors, and

[0054] - Control one or more coolers based on the one or more auxiliary temperature signals and one or more corresponding reference values.

[0055] In the 16th aspect according to any of the foregoing aspects from 2 to 15, the device includes a tunnel defining or containing a heat treatment zone, the one or more longitudinal openings being defined at the longitudinal side of the tunnel.

[0056] In aspect 17 of the preceding aspect, the thermal protection zone is located adjacent to the one or more longitudinal openings and inside the tunnel.

[0057] In accordance with aspect 18 of the preceding aspect, the walls of the tunnel facing at least the thermal protection zone, particularly the sidewalls, are formed of thermally insulating material.

[0058] In an optional aspect of this aspect, all walls of the defined heat treatment zone of the tunnel are made of thermally insulating material so as to thermally insulate the heat treatment zone from the heat protection zone.

[0059] In the 19th aspect according to any of the foregoing aspects from 2 to 18, the device includes opposing insulating walls configured to define at least a portion of a heat-protected area, the opposing insulating walls defining an elongated channel, optionally an elongated flat channel, the elongated channel being configured to receive the end portion of each container and having a proximal side terminating at the one or more longitudinal openings and a distal side in fluid communication with the atmosphere outside the heat-treated area.

[0060] In the 20th aspect, which is combined with any of the aforementioned aspects in conjunction with the first alternative to the third aspect, the longitudinal opening is in the form of a longitudinal slit, particularly a longitudinal and straight slit extending from the inlet to the outlet of the heat shrinking equipment.

[0061] In aspect 21, which is based on any of the foregoing aspects, the heat treatment zone extends horizontally.

[0062] In aspect 22 according to any aspect of aspect 21, the heat protection zone extends horizontally and is directly adjacent to the heat treatment zone.

[0063] In aspect 23 according to any of the foregoing aspects from 3 to 22, the device includes at least a pair of opposing belts having straight belt extensions facing each other, the straight belt extensions operating at or defining the one or more longitudinal openings.

[0064] In aspect 24 of the preceding aspect, each pair of opposing bands includes:

[0065] - Two opposing bands, wherein one of the bands has a wavy outer profile with grooves, and the two bands have straight extensions facing each other, the straight extensions being configured to contact but not seal the middle portion of each container being processed; or

[0066] - Two opposing strips, each having a wavy outer profile with grooves, and straight extensions facing each other, the straight extensions being configured to contact but not seal the middle portion of each container being processed; or

[0067] - Two opposing strips, each with a smooth outer contour, the outer contours of the mutually facing straight extensions of the two strips forming a gap to receive, without sealing, the middle portion of each processed container.

[0068] In aspect 25 according to aspect 23 or 24, each pair of opposing belts comprises two drive belts.

[0069] In aspect 26 according to any of the foregoing aspects, the device includes: an adjuster for adjusting the size, particularly the thickness, of one or more longitudinal openings, and / or

[0070] Another regulator, which operates on one or both of the opposing belts in each pair, adjusts the size of the gap formed by the mutually facing extensions of the two belts forming each pair, or the physical pressure between the mutually facing extensions of the two belts forming each pair.

[0071] In aspect 27 according to any of the foregoing aspects, the heat treatment zone includes a support structure configured to support the main portion of each treated container during movement from the inlet to the outlet of the heat shrinking equipment.

[0072] In any aspect of this concept, the support structure includes:

[0073] - Multiple adjacent rollers positioned at intervals along the heat treatment zone, or

[0074] - Multiple adjacent driven rollers positioned at intervals along the heat treatment zone, or

[0075] - Insert a driven roller with an idle roller positioned along the heat treatment zone.

[0076] - A sliding plane extending along the heat-treated zone, or

[0077] - A conveyor belt extending along the heat treatment zone.

[0078] In aspect 28 of the preceding aspect, the support structure has spaced-apart through openings or passages for allowing the passage of hot air from one or more heaters, said one or more heaters being located below the support structure and configured to also guide air from below the support structure toward the container being processed, such that the hot air can also impinge on the underside of the container being processed.

[0079] According to aspect 29 of any of the foregoing aspects, the container is a bag or pouch made of a heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions, ranging from 2% to 80%, optionally in both the longitudinal and transverse directions, ranging from 5% to 60%, and more optionally in both the longitudinal and transverse directions, ranging from 10% to 40%.

[0080] The 30th aspect relates to a process for heat-shrinking selected portions of a container made of or comprising a heat-shrinkable plastic film, said container being of a type having the following:

[0081] -It houses the main part of the product.

[0082] - An end portion having at least one orifice allowing gas to escape from the container, and

[0083] -The middle section connecting the main part and the end part,

[0084] The process includes:

[0085] - Heat shrink the main parts of each container, and

[0086] - During the heat shrinkage of the main part, the end portions of each container are not heat-shrinked or the heat shrinkage of the end portions of each container is significantly less than that of the main part.

[0087] In aspect 31 of aspect 30, heat shrinking the main portion of each container includes ensuring that the main portion of each container is at least above the shrinkage temperature, and

[0088] The end portions of each container are not heat-shrinkable or are made to shrink by a significantly smaller degree than the main portions, including placing the end portions of each container at a temperature below the shrinkage temperature, optionally at a temperature at least 30°C below the shrinkage temperature, and more optionally at a temperature at least 50°C below the shrinkage temperature.

[0089] The 32nd aspect relates to a process for heat-shrinking selected portions of a container made of a heat-shrinkable plastic film, said container being of a type having the following:

[0090] -It houses the main part of the product.

[0091] - An end portion having at least one orifice allowing gas to escape from the container, and

[0092] -The middle section connecting the main part and the end part,

[0093] The process includes:

[0094] - Ensure that the main body of each container is at least above the shrinkage temperature used for heat shrinking the main body of each container, and

[0095] - Meanwhile, during the heat shrinking of the main part, the end portion of each container is kept at a temperature below the shrinking temperature, optionally at a temperature at least 30°C below the shrinking temperature, and more optionally at a temperature at least 50°C below the shrinking temperature.

[0096] In aspect 33, according to any of the foregoing aspects from 30 to 32, heat shrinking the main portion of each container includes bringing the main portion of each container above 130°C, optionally between 130°C and 180°C.

[0097] In aspect 34 according to any aspect of aspect 33, during the thermal shrinkage of the main part of each container, the corresponding end part is maintained at a temperature below 100°C, particularly below 90°C.

[0098] In aspect 35, which is based on any of the foregoing aspects from 30 to 34, the process uses a heat shrinking device based on any of the foregoing aspects from 1 to 29.

[0099] The 36th aspect relates to a process for heat-shrinking selected portions of a container made of a heat-shrinkable plastic film, said container being of a type having the following:

[0100] -It houses the main part of the product.

[0101] - An end portion having at least one orifice allowing gas to escape from the container, and

[0102] -The middle section connecting the main part and the end part,

[0103] The process uses a shrinkage device according to any one of the foregoing aspects from 1 to 29.

[0104] In aspect 37 according to aspect 35 or 36, the containers are fed into the equipment inlet, wherein the main portion of each container is received in a heat treatment zone, and wherein the end portion of each container is received in a heat protection zone.

[0105] In aspect 38 according to aspect 35, 36 or 37, the container is moved from the inlet to the outlet, and wherein heating and thermal shrinkage of the main portion of each container occurs while the main portion travels along the heat treatment zone and while the end portion of each container travels along the heat protection zone.

[0106] In aspect 39, which is based on any of the foregoing aspects from 35 to 38, during the thermal shrinkage of the main portion, the middle portion of each treated container extends through one or more openings.

[0107] In aspect 40, according to any of the foregoing aspects from 35 to 39, the main portion of each heat-shrinkable container includes maintaining a heat-treated zone at one of the shrinkage temperatures, one of the shrinkage temperatures being above 130°C, optionally included between 130°C and 180°C, while simultaneously maintaining a heat-protected zone at a temperature below the shrinkage temperature, optionally at a temperature at least 30°C below the shrinkage temperature, and more optionally at a temperature at least 50°C below the shrinkage temperature.

[0108] In aspect 41, which is based on any of the aforementioned aspects from 30 to 40, hot air is used to heat the heat treatment zone.

[0109] In aspect 42, which is based on any of the foregoing aspects from 30 to 41, the thermal protection zone is cooled using coolant and / or cooling air.

[0110] In aspect 43 according to any of the foregoing aspects from 30 to 42, wherein at least during the heat shrinking of the main portion, the container undergoes continuous movement along one / the heat shrinking device, optionally at a constant speed.

[0111] In aspect 44, according to any of the foregoing aspects from 30 to 43, during the heat shrinkage of the main portion of each container, the main portion contracts and contacts the surface of the product, thereby forming a plastic skin on and around the same product, and causing air to escape from the interior of the main portion through the intermediate portion and out of the container.

[0112] In aspect 45, according to any of the foregoing aspects from 30 to 44, the one or more openings are sized such that during heating of the main portion of each container, the air inside the main portion initially causes the main portion to expand, and then thermal contraction causes the main portion to shrink and contact the surface of the product, thereby forming a plastic skin on and around the same product, thereby causing air to escape from the interior of the main portion and out of the container via the intermediate portion.

[0113] In aspect 46, according to any of the foregoing aspects from 30 to 45, during the thermal contraction of the main portion of each container, no vacuum is applied at the end of each container, such that gas is discharged from the main portion of each container only by means of the thermal contraction effect of the gas being expelled from the same main portion of the orifice.

[0114] In aspect 47 according to any of the foregoing aspects from 30 to 46, the process uses the apparatus according to any of the foregoing aspects from 23 to 27, wherein the middle portion of each container is captured between the mutually opposing straight extensions of the / each pair of straps.

[0115] In aspect 48 of the preceding aspect, the opposing straight extensions of each pair of strips contact the surface of the middle portion of each container and compress the surface, without causing obstruction of gas exiting from the main portion of each container via the middle portion.

[0116] In aspect 49, according to any of the foregoing aspects from 30 to 48, the container is a bag or pouch made of heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions, in the range of 2% to 80%, optionally in both the longitudinal and transverse directions, in the range of 5% to 60%, and more optionally in both the longitudinal and transverse directions, in the range of 10% to 40%.

[0117] The 50th aspect relates to a heat-shrinking apparatus for processing containers made of or comprising heat-shrinkable plastic film, the containers having a main portion therein for receiving a product, an end portion not occupied by the product, and an intermediate portion connecting the main portion and the end portion.

[0118] The device includes:

[0119] - A pair of opposing shrink bands, each shrink band having an operating extension facing the opposing shrink band, wherein the operating extensions have corresponding outer surfaces defining a gap between the corresponding outer surfaces, the gap being configured to receive the end portion of each container to be processed;

[0120] - A heater, which is associated with at least one of the shrink belts and is configured to bring the outer surface of at least one operating extension to a shrinkage temperature, optionally included between 130°C and 180°C, such that the end portion of each processed container passing through the gap is thermally shrunk.

[0121] In aspect 51 of the preceding aspect, the heat shrink apparatus includes a corresponding belt heater associated with each shrink belt and configured to bring the outer surfaces of the two operating extensions at least at a shrinkage temperature between 130°C and 180°C, such that the end portion of each processed container passing through the gap is heat-shrinked.

[0122] In aspect 52 according to aspect 50 or 51, the heat shrink apparatus includes a flattening body associated with each shrink band and configured to maintain at least a portion of the outer surface of the flattened extension flat.

[0123] In aspect 53 of the preceding aspect, the flattening body is positioned downstream of the belt heater associated with the same belt, relative to the direction of movement of the container being processed, which is given by the opposing shrinkage belt.

[0124] In aspect 54, according to any of the foregoing aspects from 50 to 53, each of the operating extensions is a straight extension having a corresponding outer surface, which is a flat surface.

[0125] In aspect 55, which is based on any of the foregoing aspects from 50 to 54, the gap is a planar gap of constant thickness.

[0126] In aspect 56, according to any of the foregoing aspects from 50 to 55, each shrinkage belt is an annular belt engaged between at least the respective drive pulley and the respective driven pulley.

[0127] In aspect 57 according to any of the foregoing aspects from 50 to 56, a heater associated with each shrink band is housed within a ring defined by each respective band and is configured to heat the inner surface of the respective shrink band, optionally by direct contact.

[0128] In aspect 58 of the preceding aspect, the heater associated with each shrink band is configured to heat by directly contacting the inner surface of the operating extension of the respective shrink band.

[0129] In aspect 59 according to any of the foregoing aspects from 52 to 58, the flattening body associated with each shrinkage band is housed within a ring defined by each respective band and is configured to directly contact the inner surface of the respective shrinkage band.

[0130] In aspect 60, which is based on any of the foregoing aspects from 50 to 59, the thickness of the gap is included between 0.1 mm and 2.0 mm, optionally between 0.3 mm and 1.0 mm.

[0131] In aspect 61, which is based on any of the foregoing aspects from 50 to 60, the width of each shrink band is included between 20 mm and 60 mm, optionally between 30 mm and 50 mm.

[0132] In aspect 62 according to any of the foregoing aspects from 50 to 61, the heat shrink apparatus includes a pair of rollers that operate downstream of opposing shrink belts relative to the direction of movement of the containers being processed, which is given by opposing shrink belts, the pair of rollers cooperating to define a gap therebetween for receiving the end portion of each container to be processed.

[0133] In aspect 63 according to any of the foregoing aspects from 50 to 62, the heat shrink apparatus includes a sealer configured to form a heat-sealing strip on the end portion of each bag being processed, thereby airtightly sealing each container being processed.

[0134] In aspect 64 of the preceding aspect, the seal is optionally associated with one or more rollers in the form of a heated circumferential feature on the outer surface of one of the rollers, or optionally associated with one of the opposing belts in the form of a heated feature on the outer surface of one or both opposing shrinkage belts.

[0135] In aspect 65, according to any of the foregoing aspects from 50 to 64, the container is a bag or pouch made of a heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions, in the range of 2% to 80%, optionally in both the longitudinal and transverse directions, in the range of 5% to 60%, and more optionally in both the longitudinal and transverse directions, in the range of 10% to 40%.

[0136] Aspect 66 relates to a process for heat-shrinking selected portions of a container made of or comprising a heat-shrinkable plastic film, said container being of a type having the following:

[0137] -It houses the main part of the product.

[0138] - The end portion not occupied by the product, and

[0139] -The middle section connecting the main part and the end part,

[0140] The process includes:

[0141] - Heat shrink the end portion of each container, and

[0142] - During the heat shrinkage of the end portion, the end portion of each container is not heat-shrinked or the heat shrinkage of the end portion of each container is significantly less than that of the main portion.

[0143] The 67th aspect relates to a process for heat-shrinking selected portions of a container made of a heat-shrinkable plastic film, said container being of a type having the following:

[0144] -It houses the main part of the product.

[0145] - The end portion not occupied by the product, and

[0146] -The middle section connecting the main part and the end part,

[0147] The process includes:

[0148] - Ensure that the end portion of each container is at least above the shrinkage temperature used for heat shrinking the end portion of each container, and

[0149] - During the heat shrinkage of the end portion, the main part of each container is kept at a temperature below the shrinkage temperature, optionally at a temperature at least 30°C below the shrinkage temperature, and more optionally at a temperature at least 50°C below the shrinkage temperature.

[0150] In aspect 68, according to any of the foregoing aspects from 66 to 67, heat shrinking the end portion of each container includes bringing the end portion of each container above 130°C, optionally between 130°C and 180°C.

[0151] In aspect 69 of the preceding aspect, during the thermal shrinkage of the end portion of each container, the corresponding main portion is maintained at a temperature below 100°C, particularly below 90°C.

[0152] In aspect 70, which is based on any of the foregoing aspects from 66 to 69, the process uses a heat shrinking device based on any of the foregoing aspects from 50 to 65.

[0153] The 71st aspect relates to a process for heat-shrinking selected portions of a container made of a heat-shrinkable plastic film, said container being of a type having the following:

[0154] -It houses the main part of the product.

[0155] - The end portion not occupied by the product, and

[0156] -The middle section connecting the main part and the end part,

[0157] The process uses a heat shrink device from any of the aforementioned aspects, ranging from 50 to 65.

[0158] In aspect 72 according to aspect 70 or 71, the end portion of each processed container is inserted into the gap defined by the shrink band and is thermally shrunk while traveling within the gap.

[0159] In aspect 73 according to any of the foregoing aspects from 70 to 73, each corresponding belt heater associated with each shrinkage belt is operated to bring the outer surfaces of the two operating extensions at least to a shrinkage temperature included between 130°C and 180°C, such that the end portion of each processed container passing through the gap is thermally shrunk.

[0160] In aspect 74, according to any of the foregoing aspects from 70 to 73, the end portion of each container contacts the outer surface of the flat extension and is flattened by the outer surface of the flat extension as it travels through the gap.

[0161] In aspect 75, according to any of the foregoing aspects from 70 to 74, the process includes squeezing the end portion of each processed container between a pair of rollers operating downstream of opposing shrink belts relative to the direction of movement of the processed container given by opposing shrink belts.

[0162] In aspect 76 according to any of the foregoing aspects from 70 to 75, the process includes forming a heat-sealing strip on the end portion of each processed container using the shrink tape, thereby airtightly sealing each processed container.

[0163] In aspect 77, according to any of the foregoing aspects from 75 to 76, the process includes forming a heat-sealing strip on the end portion of each bag being processed using the pair of rollers, thereby sealing each processed container airtightly.

[0164] In aspect 78, according to any of the foregoing aspects from 66 to 77, the process includes adjusting the size of the gap before processing the container.

[0165] In aspect 79, according to any of the foregoing aspects from 66 to 78, the container is a bag or pouch made of a heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions, in the range of 2% to 80%, optionally in both the longitudinal and transverse directions, in the range of 5% to 60%, and more optionally in both the longitudinal and transverse directions, in the range of 10% to 40%.

[0166] Aspect 80 relates to a packaging production line, comprising:

[0167] - A loader for a container made of or comprising a heat-shrinkable plastic film, the container having a main portion therein for receiving a product, an end portion having at least one orifice allowing gas to escape from the container, and an intermediate portion connecting the main portion and the end portion; and

[0168] -A heat shrinking device according to any one of the aspects from 1 to 29,

[0169] The loader is configured to supply the containers to the heat shrinking device, and the heat shrinking device is configured to heat shrink the main part of each container.

[0170] In aspect 81 of the preceding aspect, the loader is configured to supply the containers to the heat shrink apparatus in the form of interconnected containers or in the form of a series of separate containers.

[0171] In aspect 82 according to aspect 80 or 81, the loader includes:

[0172] - A conveyor, configured to advance the product to be packaged along an operating path.

[0173] - A film supply device configured to supply heat-shrinkable plastic film along an operating path and position the film around the product to form a near-tubular structure that accommodates the product to be packaged and is provided with longitudinal openings.

[0174] - A transverse sealer configured to form a sealing strip transverse to the formation of a plurality of said containers, each of which contains a corresponding product.

[0175] In aspect 83 according to aspect 80 or 81, the packaging production line includes a heat shrink device according to any of the aforementioned aspects from 50 to 65.

[0176] In aspect 84 of the preceding aspect, the heat shrinking device is positioned downstream of and adjacent to the heat shrinking equipment, and is configured to receive the container having a heat shrinkable main portion, and to heat shrink the end portion of each container being processed.

[0177] In aspect 85 of the preceding aspect, the heat shrink apparatus is further configured to form a heat-sealing strip across the end portion of each container being processed, so as to airtightly seal the opening and form a closed package.

[0178] In aspect 86 according to any of the foregoing aspects from 80 to 83, the packaging production line includes a vacuum station configured to receive the end portions of the containers being processed and to draw gas from each container via the orifice.

[0179] In aspect 87 of the preceding aspect, the vacuum station is located downstream of and adjacent to the heat shrinking equipment, and is configured to receive the container having a heat-shrinkable main portion from the heat shrinking equipment.

[0180] In aspect 88, according to any of the foregoing aspects from 86 to 87, the vacuum station is configured to apply a lower pressure to the end portion of the container being processed than the pressure present inside the main portion, thereby drawing gas from each container via the orifice.

[0181] In aspect 89, according to any of the foregoing aspects from 86 to 88, a vacuum station is operatively positioned between the heat shrinking equipment and the heat shrinking apparatus, and is configured to deliver a vacuum container having a heat shrinking main part to the heat shrinking apparatus.

[0182] In aspect 90, according to any of the foregoing aspects from 86 to 89, the vacuum station includes a heat sealer configured to form a heat seal strip across the end portion of each container being processed to hermetically seal the opening and form a closed package.

[0183] In aspect 91, according to any of the foregoing aspects from 86 to 90, the vacuum station comprises:

[0184] - A slender vacuum chamber with a slender opening extending along the vacuum chamber.

[0185] - A vacuum source, configured to provide an internal vacuum pressure to the vacuum chamber that is lower than the ambient pressure outside the chamber.

[0186] - A conveyor that supports the main part of the container being processed and is configured to move the container being processed relative to a vacuum chamber. The container to be emptied is positioned such that during the relative movement of each container relative to the vacuum chamber, the end portion of each container moves relative to the vacuum chamber, and the main part of each container moves relative to the outside of the vacuum chamber, with the middle portion passing through and moving relative to the elongated opening.

[0187] According to aspect 92 of the preceding aspect, the vacuum station includes:

[0188] - A first guide strip, which is arranged along the length of the elongated opening and configured to have an outer surface that contacts the end portion of each container being processed, wherein the outer surface of the first guide strip is optionally provided with a wavy shape including grooves, and

[0189] - A second guide strip, which is arranged along the length of the elongated opening, opposite to the first guide strip, and configured with a corresponding outer surface that contacts the end portion of each container being processed, wherein the outer surface of the first guide strip is optionally provided with a wavy shape including grooves.

[0190] In aspect 93 according to aspect 91 or 92, the vacuum chamber includes a first sub-chamber and a second sub-chamber, wherein a vacuum station is configured to provide a first pressure to the first sub-chamber and to provide a second pressure to the second sub-chamber that is different from the first pressure and optionally lower than the first pressure, and wherein the first pressure has an absolute pressure value lower than ambient pressure.

[0191] In aspect 94, according to any of the foregoing aspects from 80 to 93, the packaging production line includes a cutting station configured to laterally cut interconnected containers and form a plurality of separate containers, wherein the cutting station operates downstream of a heat shrinking device, particularly downstream of a heat shrinking unit.

[0192] In aspect 95, according to any of the foregoing aspects from 80 to 94, the packaging production line includes a forming station configured to form an easy-open feature, optionally a notch or a weakening line, at one of the outer perimeter boundaries of each container being processed, wherein the forming station operates downstream of the heat shrinking equipment, particularly downstream of the heat shrinking apparatus.

[0193] In aspect 96 according to any of the foregoing aspects from 80 to 95, the packaging production line includes a redirection station configured to orient each processed container such that its end portion is oriented toward the container movement direction downstream of the redirection station, wherein the redirection operates downstream of the heat shrinking equipment, particularly downstream of the heat shrinking device.

[0194] In aspect 97, according to any of the foregoing aspects from 80 to 96, the packaging production line includes a heat shrink trimmer that operates downstream of the heat shrink equipment, particularly downstream of the heat shrink apparatus, and is configured to direct hot air, optionally at a temperature included between 130°C and 180°C, at least toward the middle portion of each container being processed.

[0195] In aspect 98 of the preceding aspect, the heat shrink trimmer includes two opposing hot air blowers configured to act on opposite sides of the middle portion of each processed container, wherein the two blowers are independently controlled to bend the end portion of each processed container.

[0196] In aspect 99 according to any of the foregoing aspects from 80 to 98, the packaging production line includes a labeling station configured to apply at least one label to each processed container, optionally to the end portion of each processed container, the labeling station operating downstream of a heat shrinking device, particularly downstream of the heat shrinking unit and the repositioning station.

[0197] Aspect 100 relates to a packaging process, including:

[0198] - Provides a plurality of containers made of or comprising a heat-shrinkable plastic film, said containers having a main portion therein for containing products, an end portion having at least one orifice allowing gas to escape from the container, and an intermediate portion connecting the main portion and the end portion.

[0199] - Perform a process on the container to heat shrink selected portions of the container according to any one of the foregoing aspects from 30 to 49, thereby forming a partially shrunken container having the heat-shrunken main portion that contains the product.

[0200] In aspect 101 of the preceding aspect, the process includes providing the plurality of containers by forming a plurality of plastic containers from a heat-shrinkable plastic film, wherein the forming includes:

[0201] - Proceed the heat-shrinkable plastic film along the operating path.

[0202] - Allow the product to be packaged to move along the operating path along with the plastic film.

[0203] - Before forming the container, a plastic film is positioned around the product. The plastic film is a continuous plastic film shaped into a nearly tubular membrane structure to receive the product.

[0204] - Transverse heat-sealing strips, oriented transversely to the direction of the plastic film along the operating path, are formed on a nearly tubular membrane structure to form the plurality of containers arranged sequentially.

[0205] In the 102nd aspect according to the preceding aspect, the nearly tubular structure has longitudinal openings, optionally longitudinal side openings, and wherein the containers formed from the nearly tubular structure are in the form of interconnected containers, or, if a cutting sub-step occurs, in the form of a series of separate containers.

[0206] In aspect 103 according to any one of the foregoing aspects from 100 to 102, the process includes performing a process of heat shrinking selected portions of the container according to any one of the foregoing aspects from 66 to 79 on the partially shrunken container, thereby obtaining a container having both a main portion and an end portion that have been heat shrunken.

[0207] In aspect 104 according to any of the foregoing aspects from 100 to 103, the process includes forming a heat-sealing strip across the end portion of each container being processed to hermetically seal the opening and form a closed package.

[0208] In aspect 105 according to any of the foregoing aspects from 100 to 104, the process includes receiving the container at a vacuum station and extracting gas from each container via the orifice by applying a vacuum from the outside of each end portion.

[0209] In aspect 106 of the preceding aspect, the steps of receiving the container and extracting gas at the vacuum station occur after the main part of the container containing the product has been heat-shrinked.

[0210] In aspect 107 according to aspect 105 or 106, the steps of receiving the container and extracting gas at the vacuum station occur before the end portion of the container is heat-shrinked.

[0211] In aspect 108, according to any of the aforementioned aspects from 105 to 107, the vacuum station applies a pressure lower than that present inside the main part to the end portion of the container being processed, thereby drawing gas from each container through the orifice.

[0212] In aspect 109, according to any of the aforementioned aspects from 105 to 108, the vacuum station forms a vacuum container having a thermally shrinkable main portion.

[0213] In aspect 110, according to any of the foregoing aspects from 105 to 109, the vacuum station includes a heat sealer that forms a heat seal strip across the end portion of each container being processed to hermetically seal the opening and form a closed package.

[0214] In aspect 111 according to any of the foregoing aspects from 105 to 110, the vacuum station includes a heat sealer that forms a heat seal strip perpendicular to the end portion of each container being processed to hermetically seal the opening and form a closed package.

[0215] In aspect 112, according to any of the foregoing aspects from 105 to 111, the vacuum station comprises:

[0216] - A slender vacuum chamber with a slender opening extending along the vacuum chamber.

[0217] - A vacuum source that provides an internal vacuum pressure to the vacuum chamber, wherein the internal vacuum pressure is lower than the ambient pressure outside the vacuum chamber.

[0218] - A conveyor that supports the main part of the container being processed and moves the container being processed relative to a vacuum chamber. The container to be emptied is positioned such that during the relative movement of each container relative to the vacuum chamber, the end portion of each container moves relative to the vacuum chamber, and the main part of each container moves relative to the outside of the vacuum chamber, with the middle portion passing through and moving relative to the elongated opening.

[0219] In aspect 113 according to any of the foregoing aspects from 100 to 112, containers are interconnected, and wherein a cutting station laterally cuts the interconnected containers and forms a plurality of separate containers, wherein the cutting occurs after the main portion of the container containing the product has been heat-shrinked, and optionally after the end portion of the container has also been heat-shrinked.

[0220] In aspect 114 according to any of the foregoing aspects from 100 to 113, the process includes forming an easy-open feature, optionally a cut, notch, or weakening line, at one of the peripheral boundaries of each container being processed, wherein the formation of the easy-open feature occurs after the main portion of the container containing the product has been heat-shrinked, optionally after the end portion of the container has also been heat-shrinked.

[0221] In aspect 115 according to any of the foregoing aspects from 100 to 114, the process includes redirecting each processed container such that its end portion extends forward from the main portion toward the direction of container movement, wherein the redirection occurs after the main portion of the container containing the product has been heat-shrinked, optionally after the end portion of the container has also been heat-shrinked.

[0222] In aspect 116 according to any of the foregoing aspects from 100 to 115, the process includes a heat shrink trimming step that occurs after the main portion of the container containing the product has been heat-shrinked and after the end portion of the container has also been heat-shrinked, the heat shrink trimming step including directing hot air, optionally hot air at a temperature included between 130°C and 180°C, at least toward the middle portion of each container being processed.

[0223] In aspect 117 of the preceding aspect, the heat shrink trimming step uses two opposing hot air blowers acting on opposite sides of the end portion of each container being treated, wherein the two blowers are independently controlled and cause controlled bending of the end portion of each container being treated by guiding the respective hot air jets in a differentiated manner.

[0224] In aspect 118 according to any of the foregoing aspects from 100 to 117, the process includes applying at least one label to each of the processed containers, optionally to the end portion of each of the processed containers, wherein the labeling occurs after the main portion of the container containing the product has been heat-shrinked, optionally after the end portion of the container has also been heat-shrinked.

[0225] In aspect 119, according to any of the foregoing aspects from 100 to 118, the container is a bag or pouch made of a heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions, in the range of 2% to 80%, optionally in both the longitudinal and transverse directions, in the range of 5% to 60%, and more optionally in both the longitudinal and transverse directions, in the range of 10% to 40%.

[0226] In aspect 120, which is based on any of the foregoing aspects from 100 to 119, the process uses a packaging production line based on any of the foregoing aspects from 80 to 99.

[0227] Aspect 121 relates to an airtight sealed package obtained by using the process of any of the aforementioned aspects from 30 to 49.

[0228] Aspect 122 relates to an airtight sealed package obtained by using the process of any of the aforementioned aspects from 66 to 79.

[0229] Aspect 123 relates to airtight sealed packaging obtained by using any of the processes of the foregoing aspects from 100 to 120. Attached Figure Description

[0230] Some embodiments and aspects of the invention are described below with reference to the accompanying drawings, which are provided for illustrative purposes only and therefore for non-limiting purposes, wherein:

[0231] Figure 1 This is a schematic perspective view of a first packaging production line according to various aspects of the present invention;

[0232] Figure 2 This is a schematic perspective view of a second packaging production line according to various aspects of the present invention;

[0233] Figure 3 This is a cross-section of the heat shrink equipment, which is... Figure 1 Part of the packaging production line, and Figure 2 In the packaging production line;

[0234] Figure 4 yes Figure 3 Longitudinal cross section of the heat shrink equipment;

[0235] Figure 5 It shows Figure 3 A magnified view of the circular portion of the device;

[0236] Figure 6 It shows Figure 4 A magnified view of the circular portion of the device;

[0237] Figure 7 Is Figure 2 In the packaging production line Figure 3 A schematic perspective view of the vacuum station operating downstream of the equipment;

[0238] Figure 8 This is a schematic perspective view of a heat shrink device, which is... Figure 1 Part of the packaging production line and Figure 2 In the packaging production line;

[0239] Figure 9 This is a schematic perspective view showing another operator station, which may exist in... Figure 1 Packaging production line and Figure 2 In the packaging production line. Detailed Implementation

[0240] Agreement

[0241] It should be noted that in this detailed description, corresponding parts illustrated in the various figures are indicated by the same reference numerals. The figures may be shown to illustrate the purpose of the invention by means of non-scale representation; therefore, the parts and components illustrated in the figures relating to the purpose of the invention may be associated with schematic representation only.

[0242] The terms “upstream” and “downstream” refer to the direction of travel of containers or packages being processed along a predetermined operational path.

[0243] definition

[0244] product

[0245] The term Product P refers to any kind of article or combination of articles. For example, a product can be a food product and can be in solid, liquid, or gel form, that is, in two or more of the polymeric states mentioned above. In the food sector, products can include: meat, fish, cheese, processed meat, and various kinds of prepared and frozen meals.

[0246] Control Unit

[0247] The heat shrink equipment, heat shrink apparatus, and packaging production line described herein include at least one control unit 200, which is designed to control some or all of the steps of the process for making packaging described and claimed herein. The control unit may be a single unit or may consist of multiple different control units, such as at least one control unit associated with device 1, at least one control unit associated with device 30, and at least one control unit managing a controller for production line 50. Of course, different configurations are contemplated depending on design choices and operational needs. The term "control unit" refers to an electronic component that may include at least one of the following: a digital processor (e.g., including at least one selected from the group consisting of CPU, GPU, GPGPU), a memory (or multiple memories), analog circuitry, or a combination of one or more digital processing units and one or more analog circuitry. The control unit may be "configured" or "programmed" to perform certain steps: this can be done by any means that allows the control unit to be configured or programmed. For example, in the case where the control unit includes one or more CPUs and one or more memories, one or more programs may be stored in an appropriate group of memories connected to one or more CPUs; the one or more programs contain instructions that, when executed by one or more 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, the control unit circuitry may be designed to include circuitry configured to process electrical signals in use to perform steps associated with the control unit. The control unit may include (e.g., a microprocessor-type) one or more digital units, or one or more analog units, or a suitable combination of digital and analog units; the control unit may be configured to coordinate all actions necessary for executing instructions and instruction sets.

[0248] membrane

[0249] The films used to form the containers (e.g., bags or pouches) and packaging of the present invention are made of plastic materials, particularly polymeric materials; the films are, for example, flexible single-layer or multi-layer materials including at least one external heat-weldable layer. In the case of multi-layer films, the films may include an optional gas barrier layer and one or more protective layers.

[0250] In the currently preferred option, the film is a heat-shrinkable plastic film, which exhibits free shrinkage values ​​(measured in oil according to ASTM D2732) at 120°C in both the longitudinal and transverse directions, ranging from 2% to 80%, optionally from 5% to 60%, and particularly from 10% to 40%. As used herein, the terms "heat-shrinkable," "heat-shrinkable," and the like refer to the tendency of the film to shrink when heat is applied, such that the size of the film decreases when it is unconstrained.

[0251] The thickness of the plastic film material is preferably between 10 and 60 μm, optionally between 15 and 45 μm. In one example, the thickness of the plastic film material is between 20 and 35 μm and is heat-shrinkable, as shown by the free shrinkage values ​​indicated above.

[0252] While any plastic film of the above thickness, optionally made of a shrinkable material having the above shrinkage properties, would be sufficient to implement the claimed invention, suitable exemplary materials are disclosed in the following disclosures, which are incorporated herein by reference: EP2477813, EP2805821, EP1140493, EP987103, EP881966, EP801096.

[0253] Detailed description

[0254] Heat shrinkage device for the main part 101 of heat treatment container 100 1

[0255] exist Figure 3 and 4 In the accompanying drawings, heat shrink equipment according to various aspects of the invention is indicated by reference numeral 1. Heat shrink equipment 1 is adapted to process a container 100 having a main portion 101 therein containing the product P, and having at least one opening 102a (particularly an end opening – see...) that allows gas to escape from the container. Figure 5The container 100 comprises the end portion 102 and the intermediate portion 103 connecting the main portion and the end portion. The containers disclosed herein are of the type made of or comprising heat-shrinkable plastic film: in particular, container 100 may be a bag or pouch made entirely of heat-shrinkable plastic film material. For example, the container is a bag or pouch made of heat-shrinkable plastic film, wherein the heat-shrinkable plastic film used to make each container shows a free shrinkage value at 120°C, in both the longitudinal and transverse directions, ranging from 2% to 80% (values ​​measured in oil according to ASTM D2732). According to the currently preferred variant, the heat-shrinkable plastic film used to make each container shows a free shrinkage value at 120°C, in both the longitudinal and transverse directions, ranging from 5% to 60% or in both the longitudinal and transverse directions, ranging from 10% to 40% (values ​​measured in oil according to ASTM D2732).

[0256] Shrinkage equipment 1 includes an inlet 2 for receiving containers to be processed and an outlet 3 for delivering the processed containers. Heat treatment zone 4 (see...) Figure 3 The heat treatment zone 4 is defined between the inlet and outlet: it is configured to heat shrink the main portion 101 of the container being treated. In practice, the heat treatment zone 4 receives only the main portion 101 of the container 100 being treated and is configured to direct heat substantially only to the main portion of the container. For this purpose, the heat shrinking device 1 includes a heat protection zone 5 extending adjacent to the heat treatment zone 4 and configured to receive the end portion 102 of each container and to protect the end portion from heat from the heat treatment zone 4, such that the end portion 102 of each container 100 is not heat-shrinked or at most minimally heat-shrinked to a degree significantly less than the heat shrinkage applied to the main portion 101.

[0257] In other words, the heat shrinking device 1 is capable of selectively heat shrinking only or substantially only the main part 101 of each container being processed.

[0258] The heat protection zone 5 is connected via one or more openings 6 extending between the heat treatment zone 4 and the heat protection zone 5 (see...). Figure 5 Connected to the heat treatment zone 4: In this way, each of the containers 100 being treated can allow the corresponding main portion 101 to travel in the heat treatment zone 4, the corresponding intermediate portion 103 across one or more of the aforementioned openings 6, while the end portion 102 remains protected by the heat protection zone 5 and travels within the heat protection zone 5.

[0259] Note that, depending on the variant, the one or more openings 6 may include a single longitudinal opening extending along the entire heat treatment zone and positioned between the heat treatment zone 4 and the heat protection zone 5: the single longitudinal opening may be, for example, in the form of a longitudinal slit or a thin and elongated opening, configured to receive at least the middle portion of each processed container, such that during operation of the heat shrink apparatus, the main portion 101 of each processed container 100 is received in the heat treatment zone 4, while the end portion 102 of each processed container remains outside the heat treatment zone 4, wherein the middle portion of each container passes through the longitudinal opening 6.

[0260] In an alternative variant, the device may present a plurality of discrete openings 6 formed along the heat treatment zone, and each discrete opening 6 is configured to receive the middle portion 103 of the corresponding processed container 100, such that during operation of the heat shrinking device, the main portion 101 of each processed container is received in the heat treatment zone 4, while the end portion 102 of each processed container remains outside the heat treatment zone, wherein the middle portion of each container passes through the corresponding discrete opening 6.

[0261] To properly support the containers 100 being treated during heat treatment, the heat treatment zone 4 also includes a support structure 20 configured to support the main portion 101 of each container being treated during movement from the inlet 2 to the outlet 3 of the heat shrink equipment 1. Figure 4 As shown, the support structure 20 can be formed, for example, by a plurality of adjacent rollers 21 (e.g., idle rollers having axes of rotation orthogonal to the direction of container movement in zone 4), the plurality of adjacent rollers 21 being spaced apart along the heat treatment zone and displaceable along a closed path by a chain mechanism 22 operating at each end of the rollers 21, the closed path including a top segment extending from the inlet 2 to the outlet 3. Alternatively, the support structure 20 may include idle rollers and driven rollers, or all driven rollers, spaced apart along the heat treatment zone. Of course, other alternative designs for the support structure 20 (not shown) are conceivable, such as a simple sliding plane extending along the heat treatment zone, or a conveyor belt extending along the heat treatment zone and actively driving the main portion of the container being treated. In the case of using driven devices, such as one or more driven rollers or one or more conveyor belts, these driven devices are controlled by the control unit 200 and synchronized with the movement of a pair of belts acting on the middle portion of the package being treated (as will be explained further below).

[0262] According to one aspect, the device 1 is configured to maintain the heat treatment zone 4 at a sufficiently high shrinkage temperature to cause the membrane material used to form the container 100 to thermally shrink, while maintaining the heat protection zone 5 at a temperature sufficiently below the membrane shrinkage temperature: for example, in the currently preferred option, the device 1 is configured to maintain the heat protection zone at a temperature at least 30°C below the shrinkage temperature, and optionally at a temperature at least 50°C below the shrinkage temperature.

[0263] More specifically, the heat treatment zone 4 includes at least one heater 7, which is configured during operation of the device to maintain the heat treatment zone at a shrinkage temperature above 130°C, optionally between 130°C and 180°C, and more preferably in the range of 160 ± 10°C. The temperature range maintained in the heat treatment zone 4 depends on the material of the membrane used for the container 100 and can be set by a user on a user interface 201 associated with a control unit 200, which is operatively connected to and controls the one or more heaters 7. In the illustrated example, the device, and particularly the heat treatment zone, includes multiple independently controllable heaters 7 (e.g., controllable by the control unit 200): in possible implementations, two to five or even more independently controllable heaters 7 can be used, distributed along the longitudinal extension of the heat treatment zone 4, such as... Figure 4 As shown, this defines a plurality of corresponding independent, thermally controllable, successive longitudinal sections 4a of the heat treatment zone 4. In the example shown, the heat treatment zone also has one or more temperature sensors 8 distributed along the heat treatment zone: the control unit 200 is communicatively connected to the one or more temperature sensors 8 and the one or more heaters 7. Specifically, the control unit 200 is configured to:

[0264] - Receive temperature signals from each of the one or more temperature sensors 8, and

[0265] - Control one or more heaters 7 based on the one or more temperature signals and one or more reference values.

[0266] Specifically, the control unit 200 is configured to control one or more heaters 7 based on the one or more temperature signals and one or more reference values ​​in order to maintain the temperature of the heat treatment zone within a set temperature range of above 130°C, optionally included between 130°C and 180°C, and more optionally within 160±10°C.

[0267] From a structural perspective, each of the heaters 7 includes a heat source 7a (e.g., a resistor or IR heat source, or others) and one or more fans 7b, which are configured, for example, to blow air onto the heat source and guide hot air within the heat treatment zone via appropriate channels leading to nozzles 7c distributed on the top portion and one or more sides of the heat treatment zone 4. Figure 4 As shown, hot air is thus guided toward the container being processed from both above and one or more sides. According to an additional aspect, the aforementioned support structure 20 has spaced-apart through-holes or passages 23 for hot air from the heater 7 (this is evident in the case where the support surface is formed by rollers, and also in the case where the support surface is defined by a conveyor or sliding plane, multiple through-holes may be distributed along the support surface), the heater 7 is conveniently positioned below the support structure 20, and is configured to also guide air toward the container being processed from below the support structure, so that the hot air can also impact the underside of the container being processed. In this manner, the heat treatment zone is uniformly heated, and the main portion 101 of the container is uniformly processed using hot air, thus performing efficient heat shrinkage using hot air without the use of any liquid.

[0268] As for the heat protection zone 5, the equipment 1 is configured during operation (i.e., when the container 100 is processed and its main parts are heat-treated and shrunk in the heat treatment zone 4) to keep the heat protection zone 5 at a temperature below 100°C, especially below 90°C.

[0269] To protect the heat protection zone 5 from the heat generated in the heat treatment zone, one or more thermal insulators 9 define the heat treatment zone 4, and in particular in the form of one or more thermally insulating walls positioned at the periphery of the heat treatment zone. The thermal insulator 9 includes at least one thermally insulating wall or partition 10, which is located precisely between the heat protection zone 5 and the heat treatment zone, and defines one or more openings 6. Figure 5 As shown, two adjacent thermally insulating walls or partitions 10 may exist at one or more openings 6 on opposite sides of the same opening(s). The thermally protected area 5 of the attached example also includes a cooling structure 11 defining an elongated seat 12. Figure 5The elongated seat 12, for example, can be in the form of an elongated, flat channel, configured to receive the end portion 102 of each processed container: the seat 12 has a proximal side 12a terminating at the one or more longitudinal openings 6 for receiving the end portion of the container. In the example shown, the thermally insulating wall 10 is located between the cooling structure 11 on the side near the heat treatment zone 4 and the same heat treatment zone 4, such that, on the one hand, the wall 10 provides an insulating effect, and on the other hand, the cooling structure further acts to cool the received end portion 102. The cooling structure 11 can be formed of one or more longitudinal extensions made of a thermally conductive material (such as metal, particularly aluminum) and can be provided with heat dissipation features, such as protruding cooling fins. Figure 3 and 6 As shown, the thermal protection zone includes at least one active cooler 13, which is configured to act on the cooling structure 11 during operation of the device 1 to maintain the elongated seat 12 of the thermal protection zone at a temperature at least 30°C below the contraction temperature, and more optionally at least 50°C below the contraction temperature. For example, the thermal protection structure 5 may have multiple coolers, such as two to five coolers, distributed along the thermal protection zone and independently controllable by the control unit 200.

[0270] Each cooler 13 may be configured to cool at least the aforementioned cooling structure and may include, for this purpose, a cooling fan 13a and / or a liquid cooling system, the cooling fan 13a being configured to blow cool air toward the cooling structure 11, the liquid cooling system having a coolant source (not shown) and an associated coolant circuit 13b, the coolant circuit 13b circulating within or adjacent to the cooling structure 11 via suitable pipes or channels.

[0271] According to another aspect, the thermal protection zone may further include one or more auxiliary temperature sensors 14 operating at the thermal protection zone: in this case, the control unit 200 will be communicatively connected to the one or more auxiliary temperature sensors 14 and the one or more active coolers 13, and will be configured to:

[0272] - Receive auxiliary temperature signals from each of the one or more auxiliary temperature sensors 14, and

[0273] - Control one or more coolers 13 based on the one or more auxiliary temperature signals and one or more corresponding reference values ​​to, for example, maintain the temperature in the longitudinal seat of the cooling structure at least 30°C, optionally 50°C, lower than the shrinkage temperature, and thus avoid thermal shrinkage of the end portion 102 of the package being processed.

[0274] In the examples of the accompanying figures, the shrinkage device 1 includes a tunnel 15 (preferably formed from one or more insulating walls 16) defining or containing a heat treatment zone and an optional heat protection zone 4: as can be seen, one or more longitudinal openings are defined, for example, on the longitudinal side of the tunnel facing the heat protection zone 5. Furthermore, the heat protection zone is positioned adjacent to one or more longitudinal openings and may extend along one side of the tunnel. In the currently preferred variant, all walls of the tunnel are made of insulating material. The aforementioned longitudinal openings 6 are, for example, in the form of longitudinal slits, particularly longitudinal and straight slits, through walls 10 that extend in the tunnel and from the inlet to the outlet of the heat shrinkage device, separating the heat treatment zone from the heat protection zone.

[0275] Note that although in the example described herein the heat treatment zone and the heat protection zone extend horizontally, this does not exclude the heat shrink equipment 1 and therefore the heat treatment zone 4 and the heat protection zone 5 can be inclined or vertical, in which case the container moves from the inlet to the outlet along a non-horizontal path.

[0276] According to another aspect, a pair of opposing strips 17 have mutually facing straight strip extensions 17a that operate corresponding to the one or more openings 6. In practice, one or more openings 6 may be formed on the wall 10 between the heat treatment zone and the heat protection zone, and the two strips 17 may be placed adjacent to the one or more openings 6 and the wall 10, or alternatively, the openings may be directly defined by the mutually facing strip extensions of the two cooperating and opposing strips 17. (See from...) Figure 6 As can be seen, the two opposing belts are annular belts engaged with two or more corresponding pulleys 18, at least one of which is a driven pulley.

[0277] The opposing bands of each pair are designed according to one of the following alternatives:

[0278] - The pair of opposing belts 17 comprises two belts, one of which has a wavy outer profile provided with a groove 19; in this case, the two belts have mutually facing straight extensions configured to contact each other without sealing the middle portion of each processed container: in fact, the outer surfaces of the two belts contact the opposing outer surfaces of the middle portion of each processed container in operation, thereby facilitating transport and precise control of the containers during processing; on the other hand, the groove on one of the outer surfaces of the belts defines an air escaping channel 19a through which air / gas contained within the main portion of each container can be vented; or

[0279] - The pair of opposing bands 17 includes two opposing bands, wherein these two bands ( Figure 6 The examples shown all have a wavy outer profile with grooves 19; in this case, the two strips have mutually facing straight extensions 17a, which are configured to contact the middle portion of each processed container without sealing it: in fact, the outer surfaces of the two strips contact the opposing outer surfaces of the middle portion of each processed container in operation, thereby facilitating transport and precise control of the containers during processing; on the other hand, the grooves 19 on each of the outer surfaces of the two strips define an air escaping channel 19a through which air / gas contained within the main portion of each container can be vented; or

[0280] - The pair of opposing strips comprises two opposing strips, both of which have smooth outer contours; in this case, during operation, the outer contours of the mutually facing straight extensions of the two strips form a gap, which is used to receive, but not seal, the middle portion of each processed container; note that the strip surfaces at the straight extensions can contact the opposing side surfaces of the end portions of each processed package, however, without creating enough pressure on the end portions to seal them, but instead allowing the air / gas contained in the main part of each package to escape through the interior of the end portions to the orifice of the container.

[0281] In all the above variations, device 1 may include an adjuster for adjusting the size, and particularly the thickness, of one or more longitudinal openings 6. In possible options, additional adjusters may also be present, operating on one or both of the opposing belts in each pair of belts to adjust the size of the gap or pressure entity between the mutually facing extensions of the two belts forming each pair.

[0282] In this way, the size of one or more openings and / or the gaps between the conveyor belts can be adapted to the specific container being processed, and thus to the actual thickness of the membrane used, thereby adjusting the resistance to the air / gas passage provided by the end portion of each container. This can facilitate initial bubbling of the main portion during heat treatment in the heat treatment zone, which can initially expand due to the expansion of the gas contained therein (because, at least in the presence of the inlet and outlet orifices of the equipment, the gas inside the heat treatment zone but outside the container may easily escape to the external environment) and due to the resistance to the air passage provided by the end portion of each container, and then, as the contraction effect and associated forces increase, the main portion significantly contracts, thereby expelling most of the gas contained in the main portion of the container.

[0283] The process of using the main part 101 of the heat shrink container 100 of the equipment 1

[0284] Another aspect of the invention relates to a process for heat-shrinking selected portions of the container 100: specifically, the process uses device 1 and allows for the heat shrinking of the main portion 101 of each processed container 100, while substantially not heat-shrinking the end portions 102 of the same container, or making the heat shrinkage of the end portions of each container significantly less than that of the main portion. During the process, the container 100 is fed into device inlet 2, wherein the main portion 101 of each container is received in heat treatment zone 4, and wherein the end portion 102 of each container is received in heat protection zone 5. The movement of the container is continuous at a given and speed (greater than zero, preferably constant). Of course, discontinuous, stepwise movement is not excluded. The movement of the container may be imparted by a support structure or by a drive portion operating downstream of device 1.

[0285] Therefore, the container moves from the inlet 2 to the outlet 3: heating and thermal shrinkage of the main part 101 of each container occur as the main part travels along the heat treatment zone 4 and as the end part 102 of each container travels along the heat protection zone 5.

[0286] Heat shrinkage of the main portion 101 of each container occurs when the main portion of each container is inside the heat treatment zone 4 of the equipment 1 and reaches at least above the shrinkage temperature that causes the membrane material forming the main portion to shrink. Simultaneously, the end portion 102 of each container is maintained outside the heat treatment zone and sufficiently insulated from the heat treatment zone such that the end portion does not undergo heat shrinkage (or only undergoes minimal heat shrinkage significantly less than that on the main portion), and the end portion is continuously maintained at a temperature below the shrinkage temperature, optionally at least 30°C below the shrinkage temperature, and more optionally at least 50°C below the shrinkage temperature.

[0287] More specifically, the apparatus 1 is controlled such that the heat treatment zone 4 is heated to a temperature above 130°C, optionally between 130°C and 180°C, for the main portion of each container, while the heat protection zone maintains the corresponding end portion of each container at a temperature below 100°C, particularly below 90°C. As described above, one or more heaters 7 of the apparatus 1 are activated, and the heat treatment zone 4 is heated using hot air, which is then delivered to the main portion 101, thereby determining heat shrinkage without the use of liquid.

[0288] During the heat shrinking of the main section 101, the middle section 103 of each processed container extends through one or more openings 6 (and, if present, between opposing bands 17 of the device 1) and the end section 102 is positioned within the cooling structure 11 of the aforementioned heat treatment zone 4. During the heat treatment of the main section 101 of the container, i.e., when the heat treatment zone 4 is heated using hot air, the heat treatment zone can be cooled using coolant and / or cooling air acting on the cooling structure 11 that houses the end section of the container.

[0289] During the heat shrinkage of the main portion 101 of each container, the main portion contracts and contacts the surface of the product, thereby forming a plastic skin on and around the same product, and causing air to escape from the interior of the main portion via the intermediate portion 103 and out of the container 100 via the orifice 102a. One or more openings 6 are sized such that during the heating of the main portion 101 of each container, initially, the air inside the main portion causes it to expand (due to air passage resistance provided by the intermediate and end portions of each container positioned in the openings 6 and optionally between the bands 17); then the heat shrinkage generates a contraction force on the film of the main portion 101, causing each main portion to contract and contact the surface of the product, thereby forming a plastic skin on and around the same product, and also causing air to escape from the interior of the main portion via the intermediate portion and out of the container.

[0290] It should be noted that, according to the currently preferred option, no vacuum is applied at the end portion 102 or orifice 102a of each container during the thermal shrinkage of the main portion 101 of each container: in other words, the gas is evacuated from the main portion 101 of each container only by the thermal shrinkage effect of the gas being pushed out of the same main portion of the orifice 102, and no active action is required by a vacuum chamber or similar vacuum device operating at the orifice 102a of the end portion 102.

[0291] In the examples shown in the accompanying figures, the middle portion 103 of each container is also trapped between the opposing straight extensions 17a of the pair of bands 17, which contact and compress the surface of the middle portion of each container without causing overall blockage of gas exiting from the main portion of each container via the middle portion. The bands effectively facilitate precise control of the positioning of the end portions of the processed containers and also help drive the containers from the inlet to the outlet while keeping the escape passage 19a open for gas venting.

[0292] Therefore, the process and apparatus 1 described above allow for efficient venting of air from the main portion of the package being treated, and also allow for the stretching of the film at the main portion with the resulting positive aesthetic effect, as the main portion of the package copies the contained product as a skin and remains wrinkle-free or substantially wrinkle-free. Furthermore, since the end portions are not heat-treated, there is no risk of adhesion to the inner surface of the end portions, and thus gas can be reliably vented throughout the process without the need to apply a vacuum from the outside of the package.

[0293] Heat shrink device 30 for the end portion 102 of the heat treatment container 100

[0294] Another aspect of the present invention relates to, for example Figure 8 The heat shrink apparatus 30, shown in detail, is used to process the container 100 and is suitable for heat treatment, specifically for heat shrinking the end portion 102 not occupied by the product in the container 100. The apparatus 30 can be used, for example, with the device 1 described above, and specifically can be operated on containers already processed by the device 1 to heat shrink the end portion 102 of the container, which, as discussed above, has not been heat-treated by the device 1.

[0295] like Figure 8 As shown, the device 30 includes a pair of opposing shrink bands 31: each shrink band 31 has an operating extension 31a facing a corresponding operating extension of the opposing shrink band and forming a gap 32. More precisely, the operating extensions 31a have corresponding outer surfaces that face each other and define the aforementioned gap 32 therebetween. The gap extends along the mutually facing extensions 31a of the bands and is configured to receive the end portion 102 of each container 100 to be processed.

[0296] A belt heater 33 is associated with at least one of the shrink wraps. In a currently preferred option, the belt heater 33 is associated with each shrink wrap 31. Each belt heater 33 is configured to bring the outer surface of the operating extension 31a of the corresponding belt 31 to a shrinkage temperature sufficient to cause thermal shrinkage of the film forming the end portion of the treated package. According to one aspect, each belt heater 33 is configured to bring the outer surface of the operating extension of the corresponding belt to a shrinkage temperature between 130°C and 180°C, such that the end portion of each treated container passing through the gap is thermally shrinked.

[0297] The heat shrink apparatus 30 further includes a flattening body 34 associated with one or two shrink bands 31 and configured to maintain at least a portion of the outer surface of the flattened extension flat. The flattening body 34 may be a body of a thermally conductive material (such as metal, particularly aluminum) and is positioned downstream of a belt heater 33 associated with the same band 31 relative to the direction of movement A of the container being processed, imparted by the opposing shrink bands. Each flattening body 34 has a flat effective surface 34a acting on a corresponding operating extension 31a of the corresponding shrink band 31.

[0298] As shown in the figures, each of the operating extensions 31a is a straight extension with a corresponding outer surface, which is a flat surface, and the gap 32 is optionally a planar gap of constant thickness: the thickness of the gap may be included between 0.1 mm and 2.0 mm, optionally between 0.3 mm and 1.0 mm.

[0299] More specifically, each shrinkage belt 31 is an annular belt engaged between at least a corresponding drive pulley 35 and a corresponding driven pulley 36: each shrinkage belt 31 has a particularly large width, and specifically, the width of each shrinkage belt is included between 20 mm and 60 mm, optionally between 30 mm and 50 mm, thereby enabling efficient heat treatment of relatively large end portions.

[0300] A heater 33 associated with each shrink band is housed within a ring defined by each corresponding annular shrink band 31 and is configured to heat the corresponding shrink band by direct contact with the inner surface of the respective shrink band, and in particular the inner surface of the operating extension of the respective shrink band. Furthermore, a flattening body 34 associated with each shrink band is also housed within a ring defined by each corresponding annular band and is configured to directly contact the inner surface of the respective shrink band.

[0301] The heat shrink apparatus 30 may also include a pair of rollers 37 that operate downstream of the opposing shrink belt 31 relative to the direction of movement A of the container 100 being processed, which is given by the opposing shrink belt: the pair of rollers 37 cooperate to define a gap therebetween for receiving the end portion 102 of each processed container and for further squeezing the end portion of the processed container to minimize any wrinkles.

[0302] Finally, the device 30 may include a sealer 38 configured to form a heat-sealing strip on the end portion of each processed bag, thereby providing an airtight seal to each processed container. The sealer 38 may be separate from the components (belt and rollers), or it may be, for example, in the form of a heated circumferential feature on the outer surface of one or both rollers 37 (see...). Figure 8The heating feature is associated with one or more rollers, or optionally with one of the opposing belts in the form of a heating feature on the outer surface of one or two opposing shrink belts. The heating feature on the roller or shrink belt can be independently heated to a temperature sufficient to cause a sealing strip to form across the end portion of the package being processed. The above components of the device 30, namely the belt and associated drive pulley, heater and roller, and sealer (if present), can be controlled by the control unit 200 or by a dedicated controller of the device 30.

[0303] The process of using heat shrink device 30 to heat treat the end portion 102 of container 100.

[0304] Another aspect of the invention relates to a process for heat-shrinking selected portions of the aforementioned containers, specifically the end portions 102 not occupied by the product. The heat treatment process of the end portions 102 of the containers can be performed using the aforementioned heat-shrinking apparatus 30, and includes heat-shrinking the end portions 102 of each container: particularly, during the heat shrinking of the end portions 102 of the treated containers 100, the main portions 101 of the same container are not heat-shrinked, or in any case, the degree of heat shrinkage of the main portions 101 of the same container is significantly less than that of the end portions.

[0305] According to this process, the end portion 102 of each processed container is inserted into the gap 32 defined by the shrink band 31 of the heat shrink device 30. Figure 8 And as it travels within the gap, it thermally shrinks. For this purpose, each corresponding belt heater 33 associated with each shrinkage belt is operated to bring the outer surfaces of the two operating extensions 31a to at least a shrinkage temperature between 130°C and 180°C, such that the end portion 102 of each processed container passing through the gap 32 is also brought to the shrinkage temperature and thus thermally shrinks.

[0306] According to one aspect, the end portion 102 of each container is placed in contact with and flattened by the outer surface of the flattening extension 31a as it travels through the gap 32 between the two shrinking belts of the device 30, also due to the movement on the belt of the flattening body 34. The process may also include a step of squeezing the end portion of each processed container between the aforementioned pair of rollers 37 operating downstream of the opposing shrinking belts 31.

[0307] The process may also provide the use of the shrink tape to form a heat-sealing strip on the end portion of each processed container, thereby airtightly sealing each processed container. Alternatively or additionally, the process may provide the use of the pair of rollers to form a heat-sealing strip or additional heat-sealing strip on the end portion of each processed bag, thereby airtightly sealing each processed container.

[0308] During the aforementioned process, and while the end portions of each container are brought to temperatures above the shrinkage temperature, resulting in thermal shrinkage of the same end portion, the main portion of each container is maintained at a temperature below the shrinkage temperature, optionally at least 30°C below the shrinkage temperature, and more preferably at least 50°C below the shrinkage temperature. For example, the end portions of each container may be brought to temperatures above 130°C, optionally between 130°C and 180°C, while the corresponding main portions are maintained at temperatures below 100°C, particularly below 90°C.

[0309] Finally, according to another aspect, the process may provide (typically at the beginning of the process) a step of adjusting the size of the gap 32 before processing the container so that the gap is adapted to the membrane thickness of the container being processed.

[0310] Packaging production line 50 for producing sealed and heat-shrinkable packaging.

[0311] exist Figure 1 and Figure 2 The diagram illustrates a corresponding packaging production line 50 according to the first and second examples. Each packaging production line 50 aims to form a closed and heat-shrinkable package 110 starting from a heat-shrinkable film 51. The formed package 110 can be a bag or pouch, and in particular can be made of a heat-shrinkable plastic film showing a free shrinkage value (measured in oil according to ASTM D2732) at 120°C, in both the longitudinal and transverse directions ranging from 2% to 80%, optionally in both the longitudinal and transverse directions ranging from 5% to 60%, and more optionally in both the longitudinal and transverse directions ranging from 10% to 40%.

[0312] Figure 1 and Figure 2 The packaging production line 50 includes a loader 52 for containers 100: as already discussed, the containers have a main portion 101 therein for receiving product P, an end portion 102 having at least one orifice allowing gas to escape from the container, and an intermediate portion 103 connecting the main portion and the end portion. The production line 50 includes the aforementioned heat shrinking device 30 located downstream of and adjacent to the loader 52; the loader is configured to supply the containers 100 to the heat shrinking device 30, which is configured to heat shrink the main portion 101 of each container, as explained above.

[0313] Note that the loader 52 is configured to load the container 100 in the form of interconnected containers (e.g., Figure 1 and Figure 2 (As shown) or supplied to the heat shrink equipment in the form of a series of separate containers.

[0314] In detail, Figure 1 and Figure 2 The loader 52 of the production line includes a conveyor 53 and a film supply device 54. The conveyor 53 is configured to advance the product P to be packaged along an operating path, and the film supply device 54 is configured to supply a heat-shrinkable plastic film 51 along the operating path and position the film 51 around the product P to form a nearly tubular structure 55 that accommodates the product P to be packaged. The cross-section of the nearly tubular structure 55 can be substantially C, U, or V-shaped, and in any case forms longitudinal orifices 55a defined by the opposing longitudinal boundaries of the film 51. To obtain the nearly tubular structure 55, the film 51 can be supplied in the form of a flat film from a film source 54 including a feed roller 54a. The flat film 51 is bent by itself by a film forming device or bending device 56 to give the film the desired nearly tubular shape. Of course, it is not excluded that the film is supplied directly in a nearly tubular form from an extruder or other film supply device, or supplied in a tubular form and then opened along a longitudinal line to form a nearly tubular film structure.

[0315] The loader 52 also includes a transverse seal 57 configured to form a sealing strip 58 transverse to the nearly tubular structure 55, thereby forming a plurality of the aforementioned containers 100, each of which contains a corresponding product at a main portion 101 and has an end portion 102 with an opening, such as an open end. As mentioned above, the containers 100 can be disconnected from each other, or, as is currently preferred, supplied to the aforementioned heat shrink apparatus 1 as an interconnected chain of open containers. Once the heat shrink apparatus has processed the heat shrink of the main portion 101 of the processed container 100, the container leaving the apparatus 1 can be processed by the heat shrink unit 30, which is also Figure 1 and Figure 2 It is part of the production line.

[0316] exist Figure 1 In an alternative, the container 100 having the heat-shrinkable body portion 101 leaves the equipment 1 and goes directly to the heat-shrinkable device 30, which is located downstream of and adjacent to the heat-shrinkable equipment 1 and is configured to receive the container 100 having the heat-shrinkable body portion 101 and heat-shrink the end portion 102 of each processed container.

[0317] According to a possible variation, the heat shrink device 30 can also be configured to form a heat-sealing strip (e.g., perpendicular to the sealing strip 58) across the end portion of each container being processed to airtightly seal the opening 102a and form a closed package.

[0318] exist Figure 2In a variant, the packaging production line 50 includes a vacuum station 60 configured to receive the end portion 102 of the containers being processed and to draw gas from each container via the orifice 102a.

[0319] To be more detailed, Figure 2 The vacuum station 60 of the production line is located downstream of and adjacent to the heat shrinking equipment 1, and is configured to receive the container 100 with the heat shrinking main part 101 from the heat shrinking equipment 1.

[0320] Vacuum station 60 applies a pressure lower than that present inside the main part to the end portion 102 of the container being processed, thereby drawing gas from each container 100 through the orifice 102a and evacuating the container 100.

[0321] To be more detailed, and refer to Figure 2 and Figure 7 , Figure 2 The vacuum station 60 of the production line is operatively positioned between the heat shrinking equipment 100 and the heat shrinking device 30, and is configured to deliver vacuum containers, which have the main parts for heat shrinking and vacuuming, to the heat shrinking device 30. The device 30 then forces these containers 100 and heat shrinks their end portions 102 as described above.

[0322] It should also be noted that the vacuum station 60 may include its own heat sealer 61, which may include, for example, heat seal tape or heat seal wheel or other heat seal device, configured to form a heat seal strip across the end portion of each container being processed to hermetically seal the opening and form a closed and vacuum-sealed package.

[0323] like Figure 7 As shown, the vacuum station 60 of the example disclosed herein includes an elongated vacuum chamber 62 having an elongated opening 63 extending along the vacuum chamber, a vacuum source 64 configured to provide an internal vacuum pressure lower than the external ambient pressure to the vacuum chamber 62, and a conveyor 65 supporting the main portion of the container 100 being processed. In practice, the conveyor 65 may be a conveyor belt or other type of conveyor and is configured to move the container 100 being processed relative to the vacuum chamber, as indicated by arrow B: the containers to be emptied are positioned such that during the relative movement of each container 100 relative to the vacuum chamber 62, the end portion 102 of each container moves relative to the vacuum chamber 62, and the main portion 101 of each container moves relative to the outside of the vacuum chamber (and is located on the conveyor 65), wherein the middle portion 103 of each processed container passes through and moves relative to the elongated opening 63.

[0324] To facilitate driving and precise positioning of the end portion of each container, the vacuum station may include a first guide belt 66 arranged along the length of an elongated opening 63 and configured to contact the outer surface of the end portion of each processed container. Optionally, the outer surface of the first guide belt 66 is provided with a wavy shape including grooves. The vacuum station also has a second guide belt 67 arranged along the same length of the elongated opening 63, opposite to the first guide belt 66, and configured to contact the corresponding outer surface of the end portion of each processed container. The outer surface of the first guide belt may also optionally be provided with a wavy shape including grooves. The first and second drive belts 66, 67 are annular belts, and their movement is controlled by the control unit 200 or another controller of the production line 50, and synchronized with the movement of the conveyor 65 supporting the main portion of the containers.

[0325] According to another aspect, the vacuum chamber 62 may include at least a first sub-chamber 62a and a second sub-chamber 62b (a third or more other sub-chambers 62c may be provided): in this case, the vacuum station 60 may be configured to provide a first pressure (typically lower than the atmospheric pressure present outside the vacuum station) to the first sub-chamber 62a and a second pressure different from the first pressure and optionally lower than the first pressure to the second sub-chamber 62b, so as to maximize the flexibility of the vacuum station and the ability to extract gas from the container being processed.

[0326] Note that, in addition to or in place of sealer 61, in the absence of a separate sealer for the vacuum station and device 30, a separate sealing station may be located downstream of the vacuum station or device 30, the separate sealing station being configured to heat seal the end portion of each container (e.g., by forming one or more sealing strips transverse to the end portion) and thus form a closed package.

[0327] Figure 1 and Figure 2 The production line may also include a cutting station 70 (see also...) Figure 9 The cutting station 70 is configured to laterally cut the interconnected containers 100 and form a plurality of separate containers: the cutting station 70 operates downstream of and immediately adjacent to the heat shrinking device 1 or downstream of and immediately adjacent to the vacuum station 60 (if present), or, in the currently preferred option, downstream of the heat shrinking device 30 (see [link to relevant documentation]). Figure 1 and Figure 2 ).

[0328] According to another aspect, Figure 1 and Figure 2 The production line may also include forming station 80 (in Figure 1 , Figure 2 and Figure 9(Illustrated schematically) The forming station 80 is configured to form an easy-open feature: the easy-open feature may be a cut, notch, or weakening line formed at one of the peripheral boundaries of each processed container 100, for example, at the end portion 102 of each container. The forming station 80 operates either downstream of and immediately adjacent to the heat shrinking device 1, or downstream of and immediately adjacent to the vacuum station 60 (if present), or, in the currently preferred option, downstream of the heat shrinking device 30, for example, before or after the cutting station 70, or even at the cutting station 70.

[0329] like Figure 1 , 2 As shown in Figure 9, the packaging production line 50 may further include a redirection station 90 configured to orient each processed container 100 such that its end portion 102 is oriented toward the direction of movement of containers downstream of the same redirection station: in the example shown, the redirection station 90 guides the containers laterally relative to the operating path of containers upstream of the redirection station 90. In a currently preferred option, the redirection station 90 operates downstream of the heat shrink unit 30, and particularly downstream of the cutting station 70, to act on containers that are no longer interconnected.

[0330] In the example shown, the packaging production line 50 also includes a heat shrink trimmer 91 operating downstream of the heat shrink equipment 1, particularly downstream of the heat shrink unit 30. The heat shrink trimmer 91 may be located, for example, upstream of and adjacent to a redirection station 90 (if present). The heat shrink trimmer 91 is configured to direct hot air (optionally hot air at a temperature between 130°C and 180°C) at least toward the middle portion 103 of each container being processed, to substantially also heat shrink the middle portion that may not have been properly shrunk at the preceding station. The heat shrink trimmer 91 optionally includes two opposing hot air blowers 92 configured to act on opposite sides of the middle portion of each container being processed: the two blowers are independently controlled, for example, by a control unit 200, and are capable of controlling the curvature of the end portion of each container being processed.

[0331] at last, Figure 1 and Figure 2The production line may also include a labeling station 95 configured to apply at least one label 96 to each processed container; specifically, the labeling station 95 may be adapted to apply the label 96 to the end portion of each processed container; the labeling station 95 operates downstream of the heat shrinking unit 1, particularly downstream of the heat shrinking unit 30, and downstream of the redirection station 90 (if present). The labeling station includes a label feed roller 97, a guide roller or other guiding device 98 configured to drive and position the adhesive label 96 arriving at the labeling station on the portion of interest of each container, and a waste roller 99 for receiving a support layer 96a carrying the applied label 96.

[0332] Packaging process for using packaging production line 50 to produce closed and heat-shrink packaging.

[0333] Another aspect of the present invention relates to the use of the above-described production line 50, for example... Figure 1 Packaging production line or Figure 2 The packaging process of the packaging production line.

[0334] The process provides for forming or receiving a plurality of containers 100 of the type described above, i.e. made of heat-shrinkable plastic film, and having a main portion 101 therein for containing product P, an end portion 102 having at least one opening 102a that allows air to escape from the container, and an intermediate portion 103 connecting the main portion and the end portion.

[0335] In an alternative, the interconnected or separate preformed containers 100 of the above type can be supplied directly to the heat shrink equipment 1.

[0336] exist Figure 1 and Figure 2 In another alternative shown, the process provides in-line formation of container 100. Container formation can occur at the aforementioned loader 52 and can include:

[0337] - Proceed the heat-shrinkable plastic film 51 along the operating path.

[0338] - Ensure the product P to be packaged moves along the operating path along with the plastic film.

[0339] - Before forming container 100, a plastic film 51 is positioned around the product, the plastic film being a continuous plastic film shaped into a nearly tubular membrane structure 55 for receiving product P, the products P being appropriately spaced apart from each other in the longitudinal direction of product movement on conveyor 53.

[0340] - Transverse heat-sealing strips 58, oriented transversely to the direction in which the plastic film travels along the operating path, are formed on a nearly tubular membrane structure 55 to form the plurality of containers 100 that are arranged sequentially (and interconnected at the strips 58 in the example shown).

[0341] The nearly tubular structure 55 has a longitudinal orifice 55a, optionally a longitudinal side orifice, and the containers formed from the nearly tubular structure are in the form of interconnected containers, or, if a cutting sub-step occurs, in the form of a series of separate containers.

[0342] Regardless of how the aforementioned open container is obtained, the process then provides a process of performing heat shrinking of the main portion 101 of the container on the container using heat shrinking equipment 1, and subsequently performing heat shrinking of the end portion 102 of the treated container using heat shrinking device 30.

[0343] Once the container has been heat-shrinked at the end portion 102, the process forms a heat-sealing strip across the end portion of each container being processed to airtightly seal the opening and form a closed package 110.

[0344] Note that sealing the container using a sealer that forms a heat-sealing strip can also occur before the heat shrinkage of the end portion or after evacuation at vacuum station 60 (when the latter is present). Figure 2 (Variations).

[0345] exist Figure 2 In the variant of the production line shown, the containers that leave the equipment 1 and thus have heat-shrinkable main parts 101 are processed at the aforementioned vacuum station 60, where gas is extracted from each container 100 via the orifice 102a by applying a vacuum from the outside of each end part 102.

[0346] like Figure 2 As shown, the steps of receiving the container and extracting gas at the vacuum station 60 preferably occur after the main part 101 of the container containing product P has been heat-shrinked and before the end part 102 of the heat-shrinkable container.

[0347] Vacuum station 60 applies a pressure lower than that present inside the main part to the end portion 102 of the container being processed, thereby drawing gas from each container through the orifice and forming a vacuum container with a thermally shrinkable main part.

[0348] Vacuum station 60 can be combined with the above. Figure 2 The type of packaging production line described. In one option, vacuum station 60 may include its own heat sealer 61, which forms a heat seal strip across the end portion of each container being processed to hermetically seal the opening and form a closed package.

[0349] Containers 100 or sealed packages 110 leaving vacuum station 60 arrive at shrink unit 30, where their ends are heat-shrinked. Then, if the containers or sealed packages are still interconnected, they arrive at cutting station 70, which laterally cuts the interconnected containers to form multiple separate containers.

[0350] Subsequently, either simultaneously with or before cutting, a step is provided (at forming station 80) to form an easy-open feature, optionally a cut or notch, or a weakening line at one of the outer boundaries of each container being processed: for example, the easy-open feature may be formed after the main part of the container containing the product has been heat-shrinked, optionally after the end part of the container has also been heat-shrinked.

[0351] In the example shown, by Figure 1 and Figure 2 The process of implementing the production line also includes the step of redirecting each container being processed so that its end portion extends forward from the main portion toward the direction of movement of the container: in the example shown, the redirection occurs at redirection station 90, after the end portion 102 of the container has been heat-shrinked and before labeling.

[0352] According to another aspect, the process may provide a heat-shrink trimming step, which occurs after the main portion 101 of the container containing the product has been heat-shrinked and after the end portion 102 of the container has also been heat-shrinked; the heat-shrink trimming step (operated at trimming station 91) includes directing hot air, optionally hot air at a temperature between 130°C and 180°C, at least toward the middle portion of each container being treated. Specifically, the heat-shrink trimming step may use two opposing hot air blowers 92 acting on opposite sides of the end portion of each container being treated: the two blowers are independently controlled and cause controlled bending of the end portion of each container or closed package by differentially directing the respective hot air jets.

[0353] Finally, the process may provide the application of at least one label 96 (at labeling station 95) to each of the treated containers or packages, particularly to the end portion of each treated closed package; the labeling occurs after the end portion of the container has been heat-shrinked.

[0354] The aforementioned production line and process allow for the production of hermetically sealed packaging (e.g., hermetically sealed bags) which has reduced gas content, improved aesthetic properties due to the absence of wrinkles in the main parts of the packaging, and reduced use of film material.

[0355] Although Figure 1 and Figure 2 In this context, production line 50 and the related packaging process utilize both equipment 1 and apparatus 30, but the possibility of production lines without equipment 1 or apparatus 30 is not excluded: for example, Figure 1 The production line may not have one of equipment 1 or device 30, and Figure 2 The production line may not have one of the devices 1 or 30, and therefore only a part of the heat shrink container.

Claims

1. A packaging process, comprising: - Provide a plurality of containers (100) made of or comprising a heat-shrinkable plastic film (51), the containers (100) having a main portion (101) therein for containing a product (P), an end portion (102) having at least one orifice (102a) for allowing gas to escape from the container (100), and an intermediate portion (103) connecting the main portion (101) and the end portion (102). - Performing a process of heat-shrinking a first selected portion of the container (100) on the container (100) to form a partially shrunken container (100) having a heat-shrunken main portion (101) for containing a product (P), wherein the process of heat-shrinking the first selected portion of the container (100) includes: - Heat shrink the main part (101) of each container (100), and - During the heat shrinkage of the main part (101), the end portion (102) of each container (100) is not heat-shrinked, or the degree of heat shrinkage of the end portion (102) of each container (100) is significantly less than that of the main part (101), and - Performing a process on a second selected portion of the heat-shrinkable container (100) on the partially shrunken container (100) to obtain a container (100) having both a main portion (101) and an end portion (102) that have been heat-shrunken, wherein the process for the second selected portion of the heat-shrinkable container (100) includes: - Heat shrink the end portion (102) of each container (100), and - During the heat shrinking of the end portion (102), the main portion (101) of each container (100) is not heat-shrinked or the heat shrinking degree of the main portion (101) of each container (100) is significantly less than that of the end portion (102).

2. The process of claim 1, wherein, Providing the plurality of containers (100) is achieved by forming a plurality of plastic containers (100) from a heat-shrinkable plastic film (51), wherein the forming includes: - Proceed the heat-shrinkable plastic film (51) along the operating path, - Proceed along the operating path with the product to be packaged (P) and the plastic film (51). - Before forming the container (100), a plastic film (51) is positioned around the product (P), the plastic film (51) being a continuous plastic film (51) shaped into a nearly tubular membrane structure (55) to receive the product (P). - A transverse heat-sealing strip (58) oriented transversely to the direction of the plastic film (51) along the operating path is formed on a nearly tubular membrane structure (55) to form the plurality of containers (100) arranged in succession.

3. The process of claim 2, wherein, The near-tubular structure (55) has longitudinal openings (102a), and the containers (100) formed from the near-tubular structure (55) are in the form of interconnected containers (100), or in the form of a series of separate containers (100) if a cutting sub-step occurs.

4. The process according to claim 1, comprising forming a heat-sealing strip (58) across the end portion (102) of each processed container (100) to hermetically seal the opening (102a) and form a closed package (110).

5. The process according to claim 1, comprising receiving the container (100) at a vacuum station (60) and extracting gas from each container (100) via the orifice (102a) by applying a vacuum from the outside of each end portion (102).

6. The process of claim 5, wherein, The steps of receiving the container (100) and extracting the gas at the vacuum station (60) occur after the main part (101) of the container (100) containing the product (P) has been heat-shrinked.

7. The process of claim 5, wherein, The steps of receiving the container (100) and extracting the gas at the vacuum station (60) occur before the end portion (102) of the heat-shrinkable container (100).

8. The process according to claim 5, wherein, The vacuum station (60) applies a pressure lower than that present inside the main part (101) to the end portion (102) of the container (100) being processed, thereby drawing gas from each container (100) through the orifice (102a).

9. The process according to claim 5, wherein, The vacuum station (60) forms a vacuum-sealed container (100) with a thermally shrinkable main part (101).

10. The process according to claim 5, wherein, The vacuum station (60) includes a heat sealer (61) that forms a heat seal strip (58) across the end portion (102) of each processed container (100) to airtightly seal the opening (102a) and form a closed package (110).

11. The process according to claim 5, wherein, The vacuum station (60) includes: - An elongated vacuum chamber (62) having an elongated opening (63) extending along the vacuum chamber (62). - A vacuum source (64) provides an internal vacuum pressure for the vacuum chamber (62), the internal vacuum pressure being lower than the ambient pressure outside the vacuum chamber (62). - A conveyor that supports the main part (101) of the container (100) being processed and moves the container (100) being processed relative to a vacuum chamber (62). The containers (100) to be emptied are positioned such that during the relative movement of each container (100) relative to the vacuum chamber (62), the end part (102) of each container (100) moves relative to each other within the vacuum chamber (62), and the main part (101) of each container (100) moves relative to each other outside the vacuum chamber (62), and the middle part (103) passes through an elongated opening (63) and moves relative to each other along the elongated opening (63).

12. The process according to any one of claims 1-11, wherein, The containers (100) are interconnected, and wherein a cutting station (70) laterally cuts the interconnected containers (100) and forms a plurality of separate containers (100), wherein the cutting occurs after the main portion (101) of the container (100) containing the product (P) has been heat-shrinked.

13. The process according to claim 12, wherein, The cutting occurs after the end portion (102) of the container (100) has also been heat-shrinked.

14. The process according to any one of claims 1-11, comprising forming an easy-open feature at one of the outer perimeter boundaries of each processed container (100), wherein, The easy-open feature is formed after the main part (101) of the container (100) containing the product (P) has been heat-shrinked.

15. The process according to claim 14, wherein, The easy-open feature is formed after the end portion (102) of the container (100) has also been heat-shrinked.

16. The process according to claim 14, wherein, Easy-to-open features include cuts, notches, or weakened lines.

17. The process according to claim 16, wherein, The easy-open feature is formed after the end portion (102) of the container (100) has also been heat-shrinked.

18. The process according to any one of claims 1-11, comprising redirecting each processed container (100) such that its end portion (102) extends forward from the main portion (101) toward the direction of container movement, wherein, The redirection of each processed container (100) occurs after the main part (101) of the container (100) containing the product (P) has been heat-shrinked.

19. The process according to claim 18, wherein, Redirecting each processed container (100) occurs after the end portion (102) of the container (100) has also been heat-shrinked.

20. The process according to any one of claims 1-11, comprising a heat shrink trimming step, said heat shrink trimming step occurring after the main portion (101) of the container (100) containing the product (P) has been heat-shrinked and after the end portion (102) of the container (100) has also been heat-shrinked, said heat shrink trimming step comprising directing hot air, at least toward the middle portion (103) of each container being processed.

21. The process according to claim 20, wherein, The heat shrink trimming step includes guiding the hot air at a temperature between 130°C and 180°C.

22. The process according to claim 20, wherein, The heat shrink trimming step uses two opposing hot air blowers (92) that act on opposite sides of the end portion (102) of each treated container, wherein the two blowers (92) are independently controlled and cause controlled bending of the end portion (102) of each treated container (100) by guiding the corresponding hot air jets in a differentiated manner.

23. The process according to any one of claims 1-11, comprising applying at least one label (96) to each processed container (100), wherein, Labeling occurs after the main part (101) of the container (100) containing the product (P) has been heat-shrinked.

24. The process according to claim 23, wherein, Applying at least one label (96) to each processed container (100) includes applying at least one label (96) to the end portion (102) of each processed container.

25. The process according to claim 23, wherein, Labeling occurs after the end portion (102) of the container (100) has also been heat-shrinked.

26. The process according to any one of claims 1-11, wherein, The container (100) is a bag or pouch made of heat-shrinkable plastic film (51), wherein the heat-shrinkable plastic film (51) used to make each container (100) shows free shrinkage values ​​in oil ranging from 2% to 80% in both the longitudinal and transverse directions at 120°C.

27. The process according to any one of claims 1-11, wherein, The container (100) is a bag or pouch made of heat-shrinkable plastic film (51), wherein the heat-shrinkable plastic film (51) used to make each container (100) shows free shrinkage values ​​in both the longitudinal and transverse directions at 120°C in the range of 5% to 60%, as measured in oil according to ASTM D2732.

28. The process according to any one of claims 1-11, wherein, The container (100) is a bag or pouch made of heat-shrinkable plastic film (51), wherein the heat-shrinkable plastic film (51) used to make each container (100) shows free shrinkage values ​​in oil ranging from 10% to 40% in both the longitudinal and transverse directions at 120°C.

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