Patent Application
20250196446
The invention generally relates to packaging technology. More particularly, it is related to methods and apparatuses for attaching a protective strip over a longitudinal sealing.
Today, roll-fed packaging machines are commonly used for producing packages holding liquid food products. An advantage of using roll-fed packaging machines is speed. By continuously feed packaging material, folding this into a tube, filling food product into the tube, and sealing and cutting the tube in a lower end, food packages can be produced at impressive speed, e.g. 30 000 packages per hour. In addition to the impressive speed of roll-fed packaging machines, by having the food product held in the tube, unwanted microorganisms can efficiently be hindered from coming in contact with the food product. In this way it is made possible to produce so-called aseptic packages, that is, packages that can hold food products, such as UHT-treated milk, for several months in room temperature.
To achieve packages that can protect the food product for several months, several aspects must be considered. For instance, microorganisms should be hindered from coming in contact with the food product and sun light should be blocked out from reaching the food product, since this may deteriorate the food product. In addition, measures should be made for assuring that the packages can stand for several months. For instance, for carton packages, a protective strip, sometimes referred to as longitudinal sealing (LS) strip, can be applied inside the tube over the longitudinal sealing to provide for that the food product is hindered from coming in contact with a carton layer of the packaging material, thereby avoiding that this is dissolved by the food product.
Applying the protective strip onto the inside of the tube is today common practice for roll-fed carton packaging machines. To apply the protective strip, usually a polymer-based strip, this and the packaging material is first heated such that the protective strip and an inner plastic layer of the packaging material melt, and, secondly, the two are pressed together such that they adhere to each other.
To provide for that the protective strip adheres to both sides of the longitudinal sealing, part of the protective strip can first be attached to a first longitudinal edge of a web of packaging material and once this has been formed into the tube, the other part of the protective strip can be attached to the inside of the tube such that the joint of the tube, that is, the longitudinal sealing, is covered by the protective strip from an inside of the tube.
Even though application of protective strips has been used for many years and the technology behind has been developed and refined over the years, there is a need to further improve this process. For instance, by applying heat to melt the inner plastic layer of the packaging material, the packaging material is affected. By being able to reduce the impact of heat on the packaging material during the protective strip application, the risk that the packaging material is affected to the extent that defective packages are produced can be reduced. In addition, by being able to control this process in more detail, less heat is needed, which is positive from an environmental standpoint. Further, it is made possible to reduce the thickness of the different layers of the packaging material as well as the thickness of the protective strip, which is also environmentally beneficial.
It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to present a protective strip application process providing reliable adherence of the strip while reducing a risk of overheating the packaging material. A further object is to provide for that less material is needed for providing food safe packages.
According to a first aspect, it is provided a method for producing packages holding a food product, said method comprising
An advantage of heating the web by the first flow and the strip via the second flow is that individual heating of the two can be achieved. This provides for that a risk of over-heating can be reduced, resulting in that a risk of blisters being formed in the packaging material can be reduced, and that a risk of delamination in the packaging material can be reduced.
The individual heating also comes with the benefit that the strip and the web can be optimized for the sake of the strip application process individually. As an effect, it is made possible to use less material and/or material with lower carbon footprint, but still provide reliable food packages.
The first flow of heated air may have a first temperature, and the second flow of heated air has a second temperature, wherein the first temperature may be adjusted in accordance with properties of the packaging material, and the second temperature may be adjusted in accordance with properties of the protective strip.
The first temperature may be in the range 50 to 90 degrees Celsius and/or the second temperature may be in the range 70 to 250 degrees Celsius.
The first flow of heated air provided via the first nozzle may be directed in a first flow direction and the second flow of heated air provided via the second nozzle may be directed in a second flow direction, and the first and second flow directions may be diverted at least 90 degrees.
By having the first and second flow directions diverted 90 degrees or more, it is made possible to ensure individual heating of the web and the strip.
The first flow of heated air has a first volumetric flow rate, and the second flow of heated air has a second volumetric flow rate, wherein the first volumetric flow rate may be adjusted in accordance with properties of the packaging material, and the second volumetric flow rate may be adjusted in accordance with properties of the protective strip.
An advantage with having different volumetric flow rates in the first and second nozzle is that the heated air may be supplied from the same source, but that different heating is achieved by different volumetric flow rates.
The web of packaging material may further comprise a barrier layer arranged between the outer protective layer and the inner protective layer, wherein the barrier layer may provide for that oxygen is hindered from passing through the packaging material into the food product, wherein the first temperature of the first flow and/or the first volumetric flow rate may be adjusted such that negative impact on the barrier layer is prevented.
Since disturbances of the barrier layer could result in loss of quality of the food produced held in the package, measures should be taken to assure that the integrity of barrier layers is maintained. By heating the strip and the web individually in combination with that the first flow and/or the first volumetric flow rate is chosen such that the barrier layer is not impaired, and it is made possible to produce packages with good quality and yet provide an individually adjusted heating of the strip.
The first and second temperature and/or the first and second volumetric flow rate may be set based on measured humidity level, measured pressure and/or measured temperature in surrounding air.
An advantage of taking into account the humidity level, the pressure and/or the temperature of the surrounding air is that the heating of the strip and/or the web can be dynamically set based on the specific conditions provided at the place of the heating arrangement. Thus, by both individually heat the strip and the web and also adjust based on the measurements made on the surrounding air, an even more reliable heating can be achieved with even less negative effects on the packaging material.
According to a second aspect, it is provided an apparatus for producing package holding a food product, said apparatus comprising
The same features and advantages as presented above with respect to the first aspect also applies to this second aspect.
The first flow of heated air may have a first temperature and the second flow of heated air may have a second temperature, wherein the first temperature may be adjusted in accordance with properties of the packaging material, and the second temperature may be adjusted in accordance with properties of the protective strip.
The first flow of heated air provided via the first nozzle may be directed in a first flow direction and the second flow of heated air provided via the second nozzle may be directed in a second flow direction, and the first and second flow directions may be diverted at least 90 degrees.
The first flow of heated air may have a first volumetric flow rate, and the second flow of heated air may have a second volumetric flow rate, wherein the first volumetric flow rate may be adjusted in accordance with properties of the packaging material, and the second volumetric flow rate may be adjusted in accordance with properties of the protective strip.
The web of packaging material may further comprise a barrier layer arranged between the outer protective layer and the inner protective layer, wherein the barrier layer may provide for that oxygen is hindered from passing through the packaging material into the food product, wherein the first temperature of the first flow and/or the first volumetric flow rate may be adjusted to prevent negative impact on the barrier layer as well as on the packages produced.
The first and second temperature and/or the first and second volumetric flow rate may be set based on measured humidity level in surrounding air, measured pressure and/or measured temperature in surrounding air.
According to a third aspect, it is provided a kit of parts arranged to be mounted onto an existing filling machine, said existing filling machine comprising
The same features and advantages as presented above with respect to the first and second aspect also applies to this third aspect.
According to a fourth aspect, it is provided a method for preparing a web of packaging material and a protective strip before attaching these to each other, said method comprising
An advantage with this fourth aspect is that the risk of overheating the packaging material, thereby potentially causing blisters and/or delamination, can be reduced. It is also made possible to use less material in the web and/or the strip since the heating of the two can be fine-tuned more in detail when having information the packaging material and the protective strip material, respectively.
The information can be restricted to materials being used, but it is also possible to include production data for the protective strip material and/or the packaging material, i.e. weighing in production parameters.
Still other objectives, features, aspects and advantages of the invention will appear from the following detailed description as well as from the drawings.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which
In order to form a package 110 from the tube 106 filled with food product FP, a transversal sealing can be made in a lower end of the tube by using a transversal sealing arrangement 112. Generally, this arrangement 112 has two main functions; 1) providing the transversal sealing, i.e. welding two opposite sides of the tube together such that the product in a lower part of the tube, placed downward the sealing arrangement, is separated from the product in the tube placed upward the sealing arrangement, and 2) cutting off the lower part of the tube such that the package 110 is formed. Alternatively, instead of providing the transversal sealing and cutting off the lower part in one and the same arrangement 112 as illustrated, the step of cutting off the lower part may be made in a subsequent step by a different piece of equipment, or by the consumer if the packages are intended to be sold in a multi-pack.
To provide for that the food product FP is hindered from coming in contact with a raw edge of the packaging material PM, a protective strip 200 may be applied onto to the web 102 as illustrated in
As illustrated in
When the tube 102 is formed in the longitudinal sealing arrangement 104, the web 102, which may comprise an inner protective layer 300, an outer protective layer 302 and a cellulose-based mid-layer 304, can be folded such that the first longitudinal edge section 208 of the web 102 is placed inside a second longitudinal edge section 306 of the web 102, i.e. placed radially inwards, as illustrated by way of example in
In the longitudinal sealing arrangement 104, a second longitudinal edge section 312 of the strip 200 can be attached to the web 102 such the food product FP is hindered from coming into contact with the cellulose-based mid-layer 304. More particularly, an inside surface 314 of the second longitudinal edge section 312 of the strip 200 can be attached to an outside surface 318 of a mid-section 316 of the web 102, wherein the mid-section 316 is placed between the first and second longitudinal edge sections 208, 306 of the web 102.
In addition to the outer protective layer 300, which may be a polymer-based layer arranged to protect the cellulose-based mid-layer 304 from e.g. moisture, and the inner protective layer 302, which also may be a polymer-based layer, but arranged to protect the mid-layer 304 from the food product FP, the packaging material PM may comprise a barrier layer 320. A barrier layer may be an Aluminum foil, but it may also be e.g. a polymer-based layer and/or a barrier-coated film. A barrier layer 320, or a combination of such layers, serves for that oxygen is hindered from reaching the food product FP held in the packages 110.
As illustrated in
A problem that may arise when using induction heating, as illustrated in
Another unwanted affect that may be arise in the packaging material PM during the strip application process is that blisters are formed, pointed to by striped arrows in
The problem with the delamination and the blisters are that the packaging material PM is weakened and that food protecting properties of this may be deteriorate once the strip 200 has been applied. This may be less of a problem if the layers of the packaging material PM are even more deteriorated by e.g. the transversal sealing process performed in the transversal sealing arrangement 112, but as more efficient and well-controlled processes are provided in e.g. the transversal sealing arrangement 112 it has been found that the effects of the packaging material PM caused by the strip application also should be considered and taken into account for.
To reduce any negative effects on the packaging material PM that may be caused as an effect of the strip application process, it has been found that an air heating arrangement 900 as generally illustrated in
By having individual temperatures, T1 for the first flow 90 and T2 for the second flow 904, it is made possible to provide sufficient heating for achieving melting of strip 200 and the web 102, respectively, such that the two can be adhered together reliably, at the same time as the risk of overheating, thereby causing blisters and delamination, can be held low. In addition to individually set the first and second temperatures T1, T2, also a first and a second volume flow rate VFR1, VFR2, may be set individually. Thus, instead of having different temperatures, it may be possible to achieve different heating by having different volume flow rates.
Even though not illustrated, by measuring humidity, temperature and/or pressure in surrounding air 910, this may be taken into account when setting the first and second temperatures T1, T2 and/or the first and second volume flow rates VFR1, VFR2.
As illustrated, the first flow 904 may be directed in a first flow direction FD1 and the second flow 904 may be directed in a second flow direction FD2. By having these directions diverted 90 degrees or more, it is made possible to reduce a risk that the web 102 is heated by the second flow 908 or a risk that the strip 200 is heated by the first flow 904, thereby ensuring adequate individual heating of the two.
A mounting bracket 1000 can be provided such that the air heating arrangement 900 can easily be attached to the packaging machine 100. An advantage of having the air heating arrangement 900 placed on an outside of the packaging machine 100 and having the mounting bracket 1000, or other similar arrangement for providing easy installation, is that upgrading of existing filling machines is facilitated. An additional advantage of having the air heating arrangement 900 placed on the outside of the packaging machine 100 is that heating of the protective strip 200 and the web 102 can be monitored by an operator easily.
In a first step 1202, the web 102 can be provided, and in a second step 1204, the protective strip 200 can be provided.
In a third step 1206, the first longitudinal edge section 208 of the inside surface 214 of the web 102 can be heated by applying the first flow 904 of heated air via the first nozzle 902.
In a fourth step 1208, the first longitudinal edge section 212 of the inside surface 210 of the protective strip 200 can be heated by applying the second flow 908 of heated air via the second nozzle 906.
In a fifth step 1210, the outside surface 210 of the first longitudinal edge section 212 of the protective strip 200 can be attached onto the inside surface 214 of the first longitudinal edge section 212 of the web 102.
In a sixth step 1212, the tube 106 can be formed from the web 102 of packaging material (PM) by directing the first longitudinal edge section 208 of the web 102 inside the second longitudinal edge section 306 of the web 102.
In a seventh step 1214, the outside surface 308 of the first longitudinal edge section 208 can be attached onto the inside surface 310 of the second longitudinal edge section 306.
In an eighth step 1216, the inside surface 314 of the second longitudinal section 312 of the protective strip 200 can be attached onto the outside surface 318 of the mid-section 316 of the web 102, wherein the mid-section 316 can be placed between the first and second edge sections 208, 306, thereby providing for that the food product (FP) can be hindered from coming into contact with the cellulose-based mid-layer 304 of the packaging material (PM).
In a ninth step 1218, the food product (FP) can be filled into the tube 106.
In a tenth step 1220, the tube 106 can be transversally sealed in transversal sealing sections 114 in a lower end of the tube 106.
In an eleventh step 1222, the tube 106 can be cut in the transversal sealing sections 114 such that the packages 110 are formed.
Even though described in a particular order, the different steps may also be performed in other orders and also some of the steps may be performed in parallel, e.g. the web and the protective strip may be heated in parallel.
Even though described in a particular order, the different steps may also be performed in other orders and also some of the steps may be performed in parallel, e.g. the web and the protective strip may be heated in parallel.
From the description above follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22169797.2 | Apr 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/059911 | 4/17/2023 | WO |
