The invention relates to the domain of flexible packagings, typically bags. These bags are formed from single or multilayer strip materials, partly or entirely composed of plastic films.
It is particularly applicable to the opening of bags, when opening includes tearing of the strip material forming the bag, the strip material forming the bag being chosen from among hand tearable materials.
Commercially available bags are already known made from plastic films that can be torn during a first opening.
In general, these, bags have an opening zone typically near the top including a tear starting point or notch, typically in a “V” shape, so as to concentrate the tearing energy at a local point and thus start tearing the material from which the bag is made with a minimum manual force.
Opening of the bag requires experience in the use of a tear starting point, and such bags are usually difficult if not impossible to open by applying a manual force anywhere else than at the tear starting point, which guarantees the integrity of the bag throughout its life.
In the case of easily tearable materials, an opening method commonly called “Tircell” ®, typically composed of a striplet with mechanical properties stronger than the properties of the material to be torn, is fixed to the material to be torn, and comprising a free end at which the striplet can be pulled manually so that the said material can be torn.
Other preliminary cutting techniques are known that tend to locally weaken a material, for example by laser, in order to facilitate opening or tearing of a plastic film.
Problems that Arise
Firstly, in the case of tear-opening bags from a tear starting point, it is observed that the nature of the tear is often random.
Moreover, the tear can propagate in a given direction on one of the faces or walls of the bag, while it might propagate in a completely different direction on the other face or facing panel.
This is all very annoying, because a random propagation of the tear in the bag can purely and simply destroy the bag.
Moreover, in bag applications, there is no economic known tearable material in which the tear propagates in a predetermined manner or along a straight-line.
Furthermore, since the materials from which bags are made have increasingly high mechanical properties, a “Tircell”® type opening means would not be suitable, and in any case its production cost is relatively high. Moreover, since some existing bags may be sterilized, this opening means located outside the film to be torn would not be suitable for heat treatments such as sterilization.
Moreover, firstly the presence of a free end introduces a much greater risk of accidental opening than the presence of a tear starting point, and secondly it requires special and therefore expensive manufacturing means.
For formation of pre-cut lines, it is known firstly that they require expensive equipment, and secondly that they are difficult to use in that high precision and a uniform cut depth are necessary, and the final result may be that the material is mechanically weakened over a considerable width which can make it more difficult to maintain integrity of the packaging throughout its life.
Therefore, the applicant has attempted to find a more efficient and reliable means with greater industrial productivity to solve problems arising with the state of the art, particularly by the use of a laser.
According to the invention, packaging of a product, typically in the form of a bag, forms a container comprising two sidewalls, a bottom and a filling opening, that can be closed after the product has been packaged in the said packaging, the said container being formed from a hand tearable material typically made of a plastic strip, and comprising a first opening area containing a tear starting point typically formed on one edge of the said container in order to open the said packaging for the first time after it has been filled and sealed, the said edge typically being formed by sealing the edges of the two sidewalls.
This packaging is characterised in that, in the said first opening area:
This combination of means a) to c) provides a means of solving all problems arising with the state of the art.
The applicant has observed firstly that the presence of a first stiffening element can form a sort of barrier delimiting two zones (the so-called upper part and the so-called lower part) such that a tear initiated in one zone will not propagate to the other zone, while choosing higher mechanical characteristics for the stiffening element than for the material forming the packaging, particularly its resistance to tearing. Thus, since the tear is typically initiated in the upper part rather than in the lower part forming the part of the packaging containing the packaged product, this means guarantees integrity of the lower part, thus eliminating the risk of the product been spilled when the bag is opened.
Secondly, the applicant has observed that problems that arise when the bag is opened can be restricted by also using a guide means in order to “direct” the tear—the tear being formed starting from a tear starting point close to the said first stiffening element in the upper part or at the limit between the upper and lower parts—without it being necessary to assign a precisely predetermined or determined trajectory to the tear, the purpose being that the final consumer can open the bag in a single gesture and without the need for any accessory whatsoever, so as to obtain the simply required result.
As will become clear in the reminder of the description of the invention, the combination of means a) to c) may be applicable to all types of bags including sterilisable bags, the extra cost for its application being negligible or very low depending on the precise nature of the chosen stiffening element and the guide means.
a to 15c relate to the invention.
a, 1c, 1d, 2a, 2c, 3a, 4a, 6, 9, 10 and 12a are diagrammatic views of rectangular bags (1) with a side view of a wall (2)—to illustrate the relative position of the said stiffening element (5), the said tear starting point (4), and the presence of the said guide means (6).
a, 1d, 2a, 3a, 4a and 5 relate to bags (1) with an unsealed filling opening (13) and therefore ready to be filled, while
b, 2b, 3b, 3c and 4b show sections through sidewalls (2, 2′) of bags (1) at the said first stiffening element (5) and possibly at the said guide means (6).
a to 1c relate to a first embodiment of the invention in which the stiffening element (5) is a thread (50), and in which the said guide means (6) is formed by the use of an oriented material (60)—symbolized by “O=>” and by the sealed edge (14).
a represents the bag (1) before being filled.
b is a section along A-A in
c shows the bag (1) after it has been filled and closed.
d, corresponding to
a to 2c relate to another embodiment of the invention in which the stiffening element (5) is a (50) and in which the said guide means (6) is composed of a thread forming the said second stiffening element (61).
a shows the bag (1) before being filled.
b is a section along A-A in
c shows the bag (1) after it has been filled and closed.
a to 3c relate to other embodiments of the invention.
a shows a bag (1) in which the filling opening (13) covers the entire section of the bag, while the said top part (11) corresponding to the part of the bag torn the first time that it is opened is only in the right corner of the bag.
According to
According to
a is similar to
b is a section along A-A in
a to 8 diagrammatically illustrate two embodiments for manufacturing the strip material (7) in the form of a reel (72) designed to form the bags (1) with the insertion of the stiffening element (5) and the guide means (6) composed of a thread (50).
According to
a shows a perspective view of the strip material (7), the threads (50) being parallel to the machine direction MD of the material. As a simple example, the dashed lines (71) diagrammatically show the cutting out shape of the walls (2, 2′) in order to form the bags (1).
b shows a cross-sectional view before the two layers (70) are brought together with the threads (50) placed between them to form a strip material (7), as shown diagrammatically in the sectional view in
a shows a bag (1) in which the said stiffening element (1) and the said second stiffening element (61) are formed by a label (55) that could be printed and/or metallic, comprising a line of weakness (550) forming the said partition line, and provided with tear starting points (4) at its ends.
b shows a vertical cross-section through the bag according to
Unlike
a to 15c illustrate manufacturing of a strip material (7) in which the stiffening element (5) is a thread (50) arranged in the transverse direction TD, perpendicular to the machine direction MD.
a shows a diagrammatic view of a longitudinal section perpendicular to the strip material (7) to be made, showing a device for gluing two films (70) using an adhesive (73), a thread (50) being deposited over the entire width of the strip at regular intervals so as to obtain a material according to
According to a first embodiment of the invention, the said guide means (6) may be formed by:
This embodiment has been illustrated in
According to a second embodiment of the invention, the said guide means (6) may include a second stiffening element (61) on each sidewall (2, 2′) and typically in parallel, forming a secondary barrier to the tear, typically parallel to the said first stiffening element forming the said main barrier, the said tear starting point being located between the said main and secondary barriers so as to maintain the said tear between the said first stiffening element and the said second stiffening element during the said first opening.
The said first and second stiffening elements forming the said main and secondary barriers are preferably identical, continuous, parallel and separated by a distance typically varying from 1 to 20 mm, and preferably from 2 to 10 mm; they may possibly form a thread (50), a striplet (52) or a label (55) fixed to the said face and having a line of weakness (520, 550) typically obtained by making a preliminary mechanical cut or a laser cut, the said striplet or label on one face (2) facing the said striplet on the other face (2′).
This embodiment has been illustrated in
Note also that the two types of guide means can be combined, as illustrated in
As illustrated in all the figures, the said partition line, which generally runs along or is coincident with the line formed by the first stiffening element (5), may be a line forming a complete separation between the said upper part (11) and lower part (12). This arrangement is usually more practical or aesthetic, but it is absolutely not compulsory.
It is often advantageous if this partition line is a transverse line, so as to ensure that the said bag can be fully opened, as illustrated for example on
The nature, mechanical characteristics or thickness of the said first stiffening element (5, 50, 51, 52, 53, 54, 55) forming the said barrier should be chosen such that the propagation energy of the said tear is typically at least 20% higher at the crossing of the said main barrier (5′) than in the strip material (7) without the stiffening element. But in particular, when the first stiffening element (5) or the second stiffening element (61) are formed by the incorporation of an add-on element (thread, striplet, etc.), the propagation energy of the tear at the crossing of the said main barrier (5′) including the said first stiffening element (5) or the secondary barrier comprising the said second stiffening element (61), may be much higher, at least twice as high, or even five times as high or even more in some cases, than the propagation energy of the tear in the strip material itself, such that it becomes almost impossible for the tear to deviate from the “track” assigned to it in the design of the said packaging, the first time that it is opened.
All figures except for
The said thread (50) may be a textile thread made of a natural, artificial or synthetic material, or a metallic wire, the said thread or wire having a fracture strength equal to at least 0.5 N.
Similarly, the said striplet (51) may be a paper or metal striplet, or a single layer or multilayer plastic striplet, possibly printed.
As illustrated in
But as illustrated in
Advantageously, particularly aesthetically, the said strip material (7) may be a multilayer material, the said first stiffening element (5, 50, 51) being inserted between two layers (70) of the said multilayer material, the two layers possibly being different or identical.
The said strip material (7) may comprise at least one extruded thermoplastic layer (70) or at least two coextruded thermoplastic layers (70), or at least two layers (70) made of a complexed strip material, the said stiffening element typically being oriented in the “machine” direction MD of the strip material (70) as illustrated in
The packaging according to the invention may typically be formed either from two strip materials (7) that may be identical or different, by cutting the two materials into strips, each forming a sidewall (2, 2′) of the said packaging, and sealing of the edges to form a sealed edge (3), or from a single strip material by folding, sealing and cutting, one side of the said packaging forming a fold (15).
The said sealing may typically be heat sealing consisting of compression of the edges, particularly such that each end of the said stiffening element (5, 50, 51) is coated by the said strip material (7) by local creep of the said strip material, so as not to damage the leak tightness of the packaging.
According to the invention, the said strip material (7) may be chosen from among, or may include, one or several of the following materials: paper, metallic sheet typically made of aluminium, film or a layer of PET, PA, PP, PE in one or two directions, possibly metallised, the said material being between 20 and 200 μm thick, the said strip material being a material with 1 to 5 layers (70).
When PE is used, a tearable PE preferably at least 60 μm thick will be used.
According to one variant of the invention, the packaging may comprise an add-on bottom (18), so that a package can be obtained with an upright station.
As also shown in
One particular purpose of the invention is a bag, typically with rectangular sides (2, 2′) made of a multilayer material, typically including 2 to 4 layers, the said first stiffening element of each face (2, 2′) facing the other and being composed of a textile thread, typically made of PET or PA, parallel to the said opening (13) and typically at a distance from this edge equal to between 5 mm and 30 mm such that the said upper part (11) has a relatively small surface area compared with the said lower part, typically less than 0.2 times the surface area of the said lower part.
Depending on the case, this type of bag may have its filling opening (13) in the said upper part, as illustrated on most of the bags shown in the figures or in the said lower part (12) as illustrated in
Like the second stiffening element (61), the said first stiffening element (5) may also be located on the inner and/or outer face of the said wall (2, 2′). Thus, the invention can also be used to obtain all sorts of combinations depending on which of the two faces is considered, the first stiffening element (5) or the second stiffening element (61). If necessary, it is also possible to accumulate several embodiments for the first stiffening element (5) and for the guide means (6) as a function of technical, aesthetic, production and usage requirements.
The first stiffening element (5), and possibly the said guide means, may be composed of or may include a striplet (51, 52), for example in the form of a typically extruded profile like that illustrated in
In this case, it may be advantageous for the said striplet (51, 52) to also include a closing means, the striplet on one face typically comprising a closing element cooperating with a complementary closing element facing it on the other side, the said closing means typically being of the “ZIP” type located below the said first stiffening element in the said lower part (12).
But moreover, and independently of the stiffening element, the packaging according to the invention may include a closing means, one face (2) typically including a closing element cooperating with a complementary closing element facing it on the other side (2′), the said closing means typically being of the “ZIP” type located below the said first stiffening element in the said lower part (12).
Another purpose of the invention consists of a process for manufacturing a package according to the invention in which:
According to another variant embodiment of the invention:
According to another variant embodiment of the invention:
Regardless of which variant embodiment of the invention is used, the said first stiffening element (5) and possibly the said second stiffening element (61) may be coated typically with glue or adhesive such that they are absolutely fixed to the said strip material (7) and that there is no risk of delamination and no risk of the package losing its seal or the permeability of the package being increased.
Usually, the materials used to make the first stiffening element (5) and the second stiffening element (61) are compatible with the materials forming the said strip material (7), but if an appropriate choice of the glue or adhesive is made, it is virtually possible to make any type of first stiffening element (5) and second stiffening element (61) bond to the said strip material (7).
Depending on the case, and particularly when the said first stiffening element (5) and the second stiffening element (61) are inserted between the layers of strip material (7), the thickness ER of the said first stiffening element (5) and/or second stiffening element (61) will be chosen to be typically thin compared with the thickness of the strip material (7) EB—for example four times thinner or even 8 times thinner (10 μM vs 80 μm).
On the other hand, for example when a striplet (51, 52) or a label (55) is used, its thickness may be approximately equal to the thickness of the strip material, if necessary.
Advantageously, the said first stiffening element (5) and the said second stiffening element (61) may advantageously be identical and be formed simultaneously, in which case the strip material (7) may or may not be oriented.
Usually, the said strip material (7) may be chosen from among the following multilayer materials: PET/PP, PET/Al/PP, PET/Al/OPA/PP, PET/Al/PE, PET/Al/OPA/PE, PET/OPA/Al/PP, PET/OPA/Al/PE, PET/PE, OPP/PE, OPP/PP, OPP/OPP, OPA/PP, OPA/PE, where “Al” (also denoted “alu” or “ALU” in the figures) denotes a thin aluminium sheet, typically thinner than 20 μm, in which OPP and OPA denote oriented PP and oriented PA respectively, and “/” symbolically denotes separation between distinct layers.
According to the invention, the said strip material can also be supplied, and after the said container has been formed, the said product (8) can be packaged in the said container and the said package can be closed, typically before forming the said thinner tear starting point (4) and cutting out the said container, so as to use the so-called FFS (Form-Fill-Seal) process.
In this case, the said supplied strip material may include the said first stiffening element (5) oriented along the transverse direction TD, perpendicular to the machine direction MD of unwinding of the said strip material.
According to one variant of the process, the said supplied strip material does not include the said first stiffening element (5), the said first stiffening element (5) and the said guide means (6) may be formed or applied onto the faces (2) and (2′) if necessary when using the said FFS process.
According to the invention, the said first stiffening element (5)—and possibly the said guide means (6) if necessary—may be a striplet applied to the inside of the said container such that nothing is visible from the outside, and/or such that the external surface of the bag is smooth.
Another purpose of the invention consists of the strip material or the film (7) that will implement the process according to the invention. This material or film that will be used on automatic FFS type filling machines includes the said first stiffening element (5) and possibly the said guide means, the said first stiffening element (5) and possibly the said guide means being oriented in the machine direction MD or in the transverse direction TD.
As already mentioned, this film can be obtained using different technologies including complexing. The stiffening element (5) and the guide means are typically introduced during lamination, preferably between the two films forming the layers (70). According to one method, their positioning within the width of the strip material is adjustable, and the function will be obtained in the longitudinal direction or the machine direction MD. Obviously, as many stiffening elements or guide means as are necessary can be introduced over the width of the strip material (7) in order to:
The principle diagram in
The invention is used for applications in packaging of all types of products, for example for food products, cosmetics and household cleaning products.
Example Embodiments
All figures show example embodiments of bags (1).
The strip materials (7) used in the manufacturing tests are 12 μm/9 μm/90 μm thick PET/Al/PP, PET/Al/OPA/PP as shown in FIGS. 12 to 14, and 80 μm thick PET/PE and PEBD.
The first stiffening element (50) and the second stiffening element (61) consist of a 13 strand PA6/6 nylon thread, the diameter of each strand being 10 μm.
When completing layers (70) according to
Sterilisable bags were also made.
Tests were carried out using a metal wire or an “anti-theft” striplet designed to provide an alert, typically by triggering a siren, in the case of a fraudulent crossing between the gateways associated with cash tills in shops, as the first stiffening element (50).
Reclosable bags were also made using a 40 μm thick and 20 mm wide aluminium striplet as the first stiffening element (5) on each face, by incorporating a “ZIP” type closure.
All the manufactured bags were tested by a panel of persons representing “average consumers” opening the bags normally without taking any special care as they would in everyday life at home.
The results clearly showed that the tear propagates in a controlled and direct manner using the means according to the invention.
The invention has very many advantages.
Firstly, it divulges a new type of packaging that maintains its integrity the first time it is opened.
It also divulges a large number of ways in which the invention can be implemented.
It also divulges possibilities of simultaneously incorporating other functions in the packaging (reclosing, detection, etc.).
Finally, it may be used at no significant extra cost, depending on the embodiment.
List of Marks
Number | Date | Country | Kind |
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01/15383 | Nov 2001 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR02/03966 | 11/20/2002 | WO |