WO2013072860A2

WO2013072860A2 - Pouch, apparatus and method

Info

Publication number: WO2013072860A2
Application number: PCT/IB2012/056421
Authority: WO
Inventors: Bernhard Lang; Marco MURELLI; Riccardo ZAMMORI
Original assignee: Safta S.P.A.
Priority date: 2011-11-15
Filing date: 2012-11-14
Publication date: 2013-05-23
Also published as: WO2013072860A3; ITMO20110289A1

Abstract

An easy-opening pouch (1) is formed by joining together two multilayered sheets (15) along respective edges (7, 8, 9, 10) such that the multilayered sheets (15) form the walls of the pouch. On the multilayered sheets (15), each of which comprises at least one external layer (2) and one internal layer (6), an opening portion (14) is defined in which at least one notch (11; 11'; 11") is made on at least one of the edge (8, 9). The pouch (1) is provided with a plurality of incisions (12) that are rectilinear, continuous and/or discontinuous and parallel to one another made by a laser beam on the external layer (2) and/or on the internal layer (6). The number of the incisions (12) and the mutual distance (d) thereof are such that the notch (11; 11'; 11") is always substantially aligned on at least one incision (12). The invention further relates to an apparatus and a method for making a plurality of incisions by laser technology on one or more layers of a multilayered sheet.

Description

Pouch, apparatus and method

The invention relates to a pouch provided with easy-opening made by thermowelding together two multilayered sheets and provided with a plurality of incisions made on at least one layer of the aforesaid two sheets by laser technology.

The invention also relates to an apparatus and a method for making a plurality of incisions by laser technology on one or more layers of a sheet of multilayered material, for example for packaging.

In the packaging industry, in particular in the field of flexible pouches for food products, pouches with an easy-opening are known - and are becoming increasingly widespread. Known pouches, made with the technologies available at the moment, are packaged in the form of bags or sachets made by joining together two sheets of multilayered material, each comprising two or more layers and forming the walls of the aforesaid pouch. For example, the sheets of multilayered material that form the walls of the pouch can each comprise three layers: one external layer made of plastic material, an intermediate aluminium layer, and an internal layer made of plastic material, which can be even different from the material of the external layer. The multilayered sheets are welded together along the edge, for example at three sides of the perimeter, such as to leave only one side open, where a mouth is defined through which the product to be packaged can be introduced inside the pouch. Once the pouch has been filled, the multilayered sheets are also welded at the side of the mouth, such as to close the pouch.

Known pouches may comprise one or more intended opening lines that are weakening lines in which material is removed from one or more layers of the multilayered sheet. In particular, these intended opening lines can be obtained by mechanical removing means, for example abrasive means, which makes incisions in the outermost layer of the multilayered sheet. The incisions can be through incisions or may only partially affect the thickness of this layer.

These incisions extend transversely through the entire width of the pouch in such a manner as to join two opposite sides thereof. The incisions are made in an intended opening portion near the mouth of the pouch. On the two opposite sides between which the aforesaid incisions extend, two notches are made - one for each side - that act as opening promoting means. A user can in fact open the pouch by acting on the notch from which then the tearing propagates along the incisions made in the aforesaid intended opening portion.

One drawback of the known pouches provided with the aforesaid incisions is that the aesthetic appearance thereof is ruined as these incisions appears substantially as if they were damage suffered by the material forming the pouch. This is very serious as it could to persuade the consumer not to buy the pouch as he may question about the conservation quality of the product contained therein.

Further, if the materials are printed materials, the aforesaid incisions detract from the quality of the printed item and in some cases from the legibility of the parts containing wording or messages.

Also, a drawback of the apparatuses for making these pouches of known type is that they have significantly high maintenance costs.

It is further known to make one or more incisions, which are parallel to and spaced apart from one another, by laser technology on a layer of a multilayered sheet in such a manner as to make incision lines that defines a tearing strip that can be removed by the user for opening the pouch and that extend through the entire depth of the layer in which the incisions have been made.

A method is also known for making two straight and parallel incisions by laser on a multilayered pouch that define a tearing strip that can be removed by the user to open the pouch. The incisions are spaced apart by a certain distance in such a manner as to have a tearing strip that is sufficiently wide as to enable the pouch to be opened.

Further, in the prior art, the adjacent incisions made with laser technology cannot be too near one another because otherwise the power density - i.e. the energy per surface unit - is too high and local fusion of the material occurs. This is to be avoided because it may compromise both the opening of the pouch and the aesthetic appearance thereof.

One drawback of known pouches having the aforesaid incisions made by laser technology is that they require rather high initial opening force. Initial opening force is defined as the force that the user has to exert to start tearing of the pouch. As, for the reasons set out above, the adjacent incisions cannot be too close to one another, known pouches typically have notches that are not aligned on any incision. This is due to intrinsic reasons linked to the pouch-making process because the notches are made by a different machine from the machine that forms the reel of multilayered film. It is understood that the movement of the reel from one machine to the other causes the loss of spatial references, which means that the notches are not exactly in the desired position, i.e. in the position in which they are aligned on an incision.

The lack of alignment of the opening promoting means (i.e. the notches) on the intended opening lines (i.e. the incisions) significantly increases the initial opening force required from the user.

A drawback of known laser apparatuses and methods for making an easy-opening of the pouch is that a linear tearing (for example substantially horizontal) and an even tearing of the pouch are not assured. Consequently, easy-opening pouches of known type made with laser technology have an opening that is not effective inasmuch as the tearing of the sheet can propagate in an uncontrolled manner.

This is a serious drawback if it is considered that currently consumers and the market increasingly require pouches that meet certain aesthetic and functional requirements, including in fact that the pouch be opened by a substantially rectilinear tearing and that the pouch can be opened easily by a user exerting little force.

Another drawback of known laser apparatuses and methods is that they are not very flexible inasmuch as it is not possible to adjust the operation of the apparatus in function of the type of incision that it is desired to obtain and the type of pouch being processed. Easy-opening pouches are further known that are made by joining two multilayered sheets that form the walls thereof and are devoid of the intended opening lines. In these pouches one of more layers of material of each of the two multilayered sheets are made of a (known) polymer material, the molecular chains of which are all substantially oriented in the same direction, which then becomes the direction in which a user can open the pouch. The opening of the pouch is thus ensured by the presence of the so-called mono- axially oriented polymeric layer, the thickness of which has to be considerably greater than that of the other layers that form the pouch to ensure that the latter opens correctly. One drawback of this type of pouch that is devoid of intended opening lines is that there is no guarantee that the pouch opens in a linear and rectilinear manner, which may compromise the aesthetic appearance of the pouch.

Further, another advantage of this pouches is that they has the limit that the thickness of the layers that form the multilayered sheets thereof have to conform to precise reciprocal proportions in such a manner that the thickness of the mono-axially oriented layer is much greater than the sum of the thicknesses of the other layers, otherwise it is no longer possible to open the pouch.

One object of the invention is to provide an easy-opening pouch made from sheets of multilayered material and provided with a plurality of incisions made on at least one layer of the aforesaid sheets by laser technology.

A further object is to obtain cheap pouches that are provided with a simple and reliable opening system.

A still further object is to ensure that the pouch is opened by substantially rectilinear tearing.

Another object is to ensure that the pouch can be opened easily by a user exerting a reduced force. Another object of the invention is to improve known apparatuses and methods to make easy-opening pouches by laser technology.

Another object is to provide a laser apparatus that enables a plurality of incisions to be made on at least one layer of a sheet of multilayered material, for example for packaging. Still another object is to provide a method for making a pouch provided with a plurality of incisions made by laser technology.

According to the invention, a pouch is provided as defined in claim 1.

According to the invention an apparatus is also provided as defined in claim 14.

According to the invention a method is also provided as defined in claim 21.

The invention can be better understood and implemented with reference to the attached drawings, which shown embodiments thereof by way of non-limiting example, in which:

Figure 1 is a perspective view of an easy-opening pouch according to the invention;

Figure l a is an enlargement of a detail of Figure 1 ;

Figure lb is a version of the enlarged detail of Figure l a;

Figure 2 is a top plan view of the pouch in Figure 1 ;

Figure 3 is a partial and enlarged schematic cross section of the pouch in Figure 1 according to the line of section I II- III in Figure 2;

Figure 4 is a view like the one in Figure 2 in which a tolerance zone T is shown in which incisions can be made on the side edges of the pouch;

Figure 4a is an enlarged detail of Figure 4;

Figure 4b is a detail of a pouch made according to the prior art;

Figure 5 is a schematic perspective view of a laser apparatus for making incisions on the pouch of Figure 1.

With reference to Figures fiom 1 to 4 there is shown an easy-opening pouch 1 made by joining together by themiowelding two sheets of flexible multilayered material 15. The sheets 15, which define the walls of the pouch 1 , are joined along respective edges to form the pouch 1 , which is shaped as a bag or sachet. In particular, the sheets 15 are joined along two side edges 8, 9, an upper edge 10 at which a mouth zone of the pouch 1 is defined, and a bottom zone 7, which can enable the pouch 1 to remain in a vertical position when it is resting on a plane. The pouch 1 according to the invention is therefore a pouch of the so-called "stand-up" type.

It is understood that the teachings of the present invention can also be used for making pouches different from the aforesaid type, in particular even pouches shaped as envelopes, which are thus not enable to remain in a vertical position when they are resting on a plane. As is visible from the section in Figure 3, each sheet of multilayered material 15 may comprise, for example, three layers that are joined together by adhesive layers that are interposed therebetween. In particular, the embodiment shown comprises in sequence (from the outside to the inside) one external layer 2 made of polyester, one adhesive layer 3 (for example resin or the like), a layer 4 made of a material having the property of being substantially totally impermeable to gases and/or water vapour (such as, by way of non- limiting example: aluminium, EVOH, PVDC, etc.) and for this reason called "barrier layer", another adhesive layer 5, and one internal layer 6 made of one or more type of polypropylene (PP).

The external layer 2 may have a thickness comprised between 3 and 36 micron, the barrier layer 4 may have a thickness comprised between 3 and 45 micron and the internal layer 6 may have a thickness comprised between 12 and 200 micron, preferably between 50 and 80 micron.

In one embodiment that is not shown each multilayered sheet 15 may comprise only two layers, being, for example, devoid of the barrier layer 4.

In another embodiment that is not shown each multilayered sheet 15 can on the other hand comprise four layers, in which one of the internal layers is a barrier layer and the other internal layer is made of a material that bestows on the pouch better mechanical properties such as, by way of non-limiting example, polyamide.

In a further embodiment that is not shown, the number of layers of each multilayered sheet 15 can be further greater (than four) to bestow specific properties on the pouch. In a further embodiment that is not shown, the two sheets 15 that form the pouch 1 can have different layers from one another, both in number and composition.

In another embodiment that is not shown the internal layer 6 of each of the two sheets 15 that form the pouch 1 can be made of a polymeric material provided with great stiffness, where by stiffness the intrinsic property of the material is meant that is defined as the measurement of the resistance provided by an elastic body to deformation and to flexure. Examples of these materials with great stiffness can be: polyester, PVC, cellophane, polystyrene, polycarbonate, in addition to various types of mono-axially oriented polypropylene and bi-axially oriented polypropylene, various types of mono-axially oriented polyethylene and bi-axially oriented polyethylene in which the orientation of the chains of molecules in at least one direction is substantially parallel to the direction defined by the upper edge 10.

The internal layer 6 made of a polymeric material provided with great stiffness (in general the aforesaid mono-axially and/or bi-axially oriented polypropylene and polyethylene) is particularly advantageous if the thickness of the internal layer 6 is less than or the same as 70 micron. In fact, when the layers 2, 4, 6 that form the sheets 15 have an overall reduced thickness, it is preferable for the external layer 6 to be made of one of these materials, which, owing to the great stiffness thereof - bestows good mechanical and structural properties on the pouch 1.

On each of the two side edges 8, 9 of each sheet 15 a notch, for example a V-shaped notch 1 1 , is made near the upper edge 10. The two notches 1 1 are made in an opening portion 14 of the pouch 1 in suitable positions of the side edges 8 and 9 in such a manner that they substantially face one another. The opening portion 14 is defined near the mouth of the pouch 1 , i.e. near the upper edge 10. The notches 1 1 are made inside a tolerance zone T (Figure 4), shown enlarged in Figure 4a. The notches 1 1 are made by a cutting machine supplied with a multilayered reel from which the sheets 15 are obtained. The movement of the multilayered reel from the machine that makes the reel to the cutting machine inevitably generates positioning and/or machining tolerances. Due to this, the notches 1 1 will not be exactly in the intended or desired position but are by contrast comprised within a tolerance zone T that may typically have a width that is equal to about three millimetres.

In an embodiment that is not shown, the opening portion 14 (and thus the notches 1 1 ) may be defined in any other zone of the sheets 15, for example a middle zone (substantially equidistant from the upper edge 10 and from the bottom edge 7) or near the bottom edge 7.

In the opening portion 14 between the notches 1 1 a plurality of incisions 12 (Figures 2 and 3) extend that are substantially parallel to the upper edge 10. In the embodiment shown the plurality of incisions 12 comprises seven incisions that are parallel to one another, which are not generally visible on the pouch 1 to the naked eye.

As is more clearly visible in the enlargements in Figure l a and 4a, the tip of the "V" of the notch 1 1 faces the plurality of incisions 12, and is in particular positioned at any incision of the plurality of incisions 12 in such a manner that the notch 1 1 is aligned on one incision 12 (as shown by the dashed line of Figures l a and by the arrows in Figure 4a). Thus, owing to the extremely reduced distance between two adjacent incisions (as will be explained in greater detail below), also the fact that the position of the notches 1 1 can vary within the tolerance zone T does not compromise the alignment of a notch to a respective incision.

By way of example, in Figure 4a a notch 1 1 ' is shown that has the tip of the "V" aligned on the second incision (starting from the top edge 10 of the pouch) of the plurality of incisions 12, a notch 1 1 is shown having the tip of the "V" aligned on the fourth incision of the plurality of incisions 12 and a notch 1 1 " is shown having the tip of the "V" aligned on the sixth incision of the plurality of incisions 12. In other words, the fact that adjacent incisions 12 are so close to one another guarantees that the notches 1 1 , 1 1 ', 1 1 " are substantially always aligned on an incision of the plurality of incisions. This occurs for any position of the notch 1 1 , 1 1 ', 1 1 " inside the tolerance zone T. Also if a notch 1 1 , 1 1 ' and 1 1 " is not exactly aligned on an incision 12 (as on the other hand shown in Figure 4a), it would be at such a short distance from the latter that in practice it is possible to state that a notch 1 1 , 1 , 1 1 " is substantially always aligned on an incision 12.

The alignment between the tip of the "V" of the notch 1 1 , 1 Γ, 1 1 " and (any) one incision of the plurality of incisions 12 ensures that the pouch is opened in a substantially rectilinear manner with a limited initial opening force required from the user.

This enables a serious drawback of known pouches to be overcome in which, as shown in the enlarged detail of Figure 4b, the tip of the V-shaped notch and the incision line nearest thereto can be at a certain distance from one another. As said, the lack of alignment between the notch and the incision line means that the user has to exert a significant initial opening force.

The opposite notches 1 1 on the two side edges 8, 9 can face two opposite ends of the same incision 12 but can also face different incisions 12, for example two adjacent incisions. Also in this case the pouch is opened in a substantially rectilinear manner requiring a reduced force from the user.

In the same manner the notches 1 1 made on the two sheets 15 to be coupled together can face the same incision 12, but also different incisions, for example two incisions that are adjacent to one another.

The enlargement of Figure lb shows an embodiment of the pouch 1 in which some incisions 12 and the notches 1 1 made on the two sheets 15 forming the pouch 1 are not in exactly corresponding positions. In fact, the plurality of incisions 12 and the notches 1 1 of the rear sheet 15 (shown by dashed lines) are slightly staggered in relation to those of the front sheet 15, as shown by the arrows F.

In general, the plurality of incisions 12 may comprise a number of incisions comprised between two and eleven, in particular between five and nine. In the shown embodiment the plurality of incisions 12 comprises, by way of non-limiting example, seven incisions. The adjacent incisions 12 can be spaced apart from one another by a distance comprised between 30 micron and 10 mm, in particular comprised between 50 micron and 1.3 mm, for example equal to 0.5 mm.

The incisions are made in the external layer 2 and affect the whole thickness thereof. In other words, the maximum depth of the incision is substantially equal to the thickness of the external layer 2. The incisions 12 made on the outer layer 2 (visible to the user) enable the layers 6, 4 of the pouch itself not to be weakened, whilst not detracting from the aesthetic appearance thereof, which layers 6, 4 giving to the pouch 1 the desired mechanical and structural properties, in particular if the internal layer 6 is made of a very stiff material like those listed above.

In one embodiment of the invention that is not shown the incisions 12 affect the thickness of the external layer 2 only partially.

In one embodiment of the invention that is not shown the plurality of incisions 12 can be made on the internal layer 6 of both the aforesaid multilayered sheets 15, i.e. on the internal layer 6 in contact with the product 13. Similarly to the embodiment shown, also in this embodiment the incisions 12 can be in a number comprised between two and eleven and can extend in depth for the entire thickness of the internal layer 6, or only for part thereof. In this case the internal layer 6 is not made of one of the materials listed above.

In another embodiment of the invention that is not shown the incisions 12 can be made on both the external layer 2. and on the internal layer 6 and also in this case they can extend through the entire thickness of these layers, or only for part thereof.

In a further embodiment of the invention that is not shown the pouch 1 may comprise incisions 12 made on the external layer 2 of one of the two sheets 15, and other incisions 12 made on the internal layer 6 of the other sheet 15.

In another embodiment of the invention that is not shown, the incisions 12 can be made only in one of the two sheets 15 that form the pouch 1 (or on the external layer 2 thereof, or on the internal layer 6 thereof).

An advantage of the invention is to provide an easy-opening pouch 1 provided with a plurality of incisions 12 made on at least one layer 2, 6 by laser technology.

Another advantage is to have an effective opening of the pouch 1 owing to the presence of a plurality of incisions 12 that extend parallel to one another at an extremely reduced distance from one another. This enables the pouch 1 to be opened easily even if the incisions 12 or the notches 1 1 made on the two coupled multilayered sheets 15 do not precisely face one another. In this case, in fact, tearing of the multilayered sheet 15 spreads from the notches 1 1 along the incisions 12 of the two coupled sheets 15 nearest the notches 1 1 . This is possible owing to the extremely reduced distance d between the incisions 12, which means that the notches 1 1 are substantially always almost aligned on one of the incisions 12. This enables the initial opening force of the pouch to be reduced significantly. Experimental tests have revealed that to open a pouch according to the invention an initial opening force suffices that is about 15% less than the initial opening force required to open known pouches having laser incisions.

Further, owing to the reduced distance d at least one of the incisions 12 made on a multilayered sheet 15 is always substantially superimposed on at least one of the incisions 12 of the other multilayered sheet 15 joined to the aforesaid sheet. Further, even if the remaining incisions 12 were not exactly superimposed on the corresponding incisions 12 of the other sheet 15, they would be staggered by a minimum distance, which does not affect neither the linear tearing during opening, nor the force to be exerted by the user. Owing to this, an easy opening of the pouch 1 is obtained which is pleasant from the aesthetic point of view, even if the tearing spreads along an incision 12 of a multilayered sheet 15, and along another incision (that is not superimposed on the aforesaid incision) of the other multilayered sheet 15 joined to the aforesaid sheet.

A further advantage is that the pouch 1 is opened in a substantially linear manner along the direction in which the incisions 12 extend and does not therefore spoil either the aesthetic appearances of the pouch 1 , or the functional features thereof. This is possible owing to the distance d, which being so reduced causes that even if the tearing spreads from one incision 12 to an incision adjacent thereto, this is not visible to the naked eye. Also, owing to this, in an initial opening step the tearing moving from the notch 1 1 to one of the incisions 12 nearest thereto does not deviate from a linear pattern in a manner that is visible to the naked eye.

Still another advantage is that the pouch 1 is cheap and easy to open.

Another advantage is that the incisions 12 permit easy-opening of the pouch without compromising the hermetic seal thereof.

Another advantage is that the incisions 12 do not spoil the aesthetic appearance of the pouch 1 , which is not damaged even after it has been opened. The zone in which the tear spreads is in fact substantially devoid of significant surface defects.

It should be noted that in the embodiment in which the pouch 1 comprises an internal layer 6 made of a material with a great stiffness (for example a mono-axially oriented polymer), the force required from the operator to open the pouch 1 is even less precisely because, whilst the easy-opening of the pouch 1 is ensured by the plurality of incisions 12, the pouch, which may in this case have a very reduced overall thickness of the sheets 15, has improved mechanical and structural properties.

The plurality of incisions 12 is made by an apparatus 20, shown in Figure 5 and disclosed below, operating with laser technology. The apparatus 20 comprises an optical unit 21 provided with a plurality of elements that are of known type and are not therefore disclosed here in detail and is arranged for receiving at least one main laser beam 30. The latter can come directly from a laser source (which is not shown) or can be obtained by dividing in turn a laser beam coming from a source.

The optical unit 21 comprises diffractive means 28 of known type (schematised in Figure 5 as a plurality of lenses) to divide the main laser beam 30 into a plurality of laser beams 3 1. The optical unit 21 is assembled such as to enable the arrangement of the optics of the diffractive means 28 to be changed rapidly by an operator in such a way as to modify consequently the mutual distance d between two adjacent incisions 12 and simultaneously to modify the number of laser beams 31 into which the main laser beam 30 is divided. The diffractive means 28 is associated with a diffractive element 22 of said optical unit 21 that is shaped like a drawer and received in a housing 23 made in said optical unit 21 having a shape that is complementary to the diffractive element 22. The housing 23 can receive a plurality of diffractive elements 22 one at a time that are interchangeable with one another (one of which is shown already inserted into the optical unit 21 in Figure 4), each of these elements being provided with respective diffractive means 28. The operator can thus insert and remove rapidly the diffractive element 22 inside the housing 23 choosing each time the diffractive element 22 provided with the diffractive means 28 that enables the desired number of beams 31 to be obtained.

Further, the optical unit 21 comprises adjusting means 24 acting on the arrangement of the optics of the diffractive means 28 in such a manner as to vary the mutual distance (linear and/or angular) between the aforesaid laser beams 3 1 exiting the optical unit 21 . In particular, the adjusting means 24 comprises an adjustable element 25, for example a knurled ring nut, provided with a graduated reading scale, such that the operator can set precisely the desired distance between the laser beams 3 1 simply by rotating this element as indicated by the arrow R.

Downstream of the optical unit 21 , the apparatus 20 comprises a focussing unit 26 arranged for focussing the aforesaid laser beams 31 exiting the optical unit 21 . The focussing unit 26 typically comprises only one lens 27. The lens 27 can have a focal length that is comprised between approximately 2.5 cm and 12.5 cm.

Owing to the lens 27 from the focussing unit 26 focussed beams 32 exit that are provided with an appropriate power density that will then cut the layer of sheet 1 in a substantially punctiform manner to make the incisions 12. The focussing unit 26 can be adjusted in such a manner as to obtain the focus of the laser beams 3 1 that is most appropriate to the incision that is being made. In order to do so, it is possible to move and/or rotate the lens 27, or, alternatively, move the focussing unit 26 in such a manner as to move it towards or away from the multilayered sheet 15 being processed by a suitable quantity along the direction indicated by the arrow A.

In one embodiment that is not shown the focussing unit 26 comprises a plurality of lenses 27.

In Figure 5, for the sake of clarity only three laser beams 31 and three focussed beams 32 are shown. The apparatus 20 can nevertheless operate in such a manner as to obtain a number of focussed beams 32 comprised between two and eleven. For example, in order to make the pouch 1 shown in Figures 2 and 3 that has seven incisions, the apparatus 20 is configured in such a manner as to emit, downstream of the focussing unit 26, seven focussed beams 32 that, by cutting the external layer 2 of the multilayered sheet 15, make the seven incisions 12.

Both the optical unit 21 and the focussing unit 26 may comprise connections (that are not shown) to deliver to the interior thereof air and/or inert gas in order to protect the optics. The apparatus 20 can be comprised in an automatic machine that is not shown that is arranged along the processing line that makes the pouch 1 .

In particular, the automatic machine can be a cutting machine that receives the incoming continuous multilayered sheet unwound from a reel and cuts the continuous multilayered sheet to make the walls that will form the pouch 1 once they will be thermowelded together along the edges. The incisions 12 are made on suitable position of the continuous multilayered sheet before the machine cuts the sheet.

Alternatively, the automatic machine can be a coupling machine that couples together the multilayered sheets 15 cut previously from the cutting machine in such a manner as to form the pouch 1. In this case, the apparatus 20 makes the incisions 12 on each of the two multilayered sheets 15 in suitable positions in such a manner that corresponding incisions of the two coupled sheet 15 substantially face one another once the pouch 1 is formed. The operation of the apparatus 20, which is also an object of the present invention, is disclosed below.

Before driving the apparatus 20, in function of the number of incisions 12 that it is desired to make on the external layer 2 (or on the internal layer 6), the operator inserts into the optical unit 21 the diffractive element 22 having the suitable optics to enable the diffractive means 28 to divide the main laser beam 30 into the desired number of laser beams 31 .

Further, in function of the distance that it is desired to have between the two adjacent incisions 12, the operator acts on the adjusting means 24 (in particular on the graduated ring nut 25) to set the outlet distance of the laser beams 3 1. Subsequently, the operator positions the focussing unit 26 in a defined configuration, either by adjusting the position of the lens/lenses 27, or by moving the focussing unit 26 along the direction A.

At this point it is possible to drive the apparatus 20, thus obtaining the desired number of focussed beams 32 (at the desired distance d from one another) starting with a single main laser beam 30.

An advantage of the invention is to provide an apparatus 20 and a method that enable incisions 12 to be made on a layer 2, 6 of a flexible multilayered sheet 15, in particular a multilayered sheet 15 for packaging.

Another advantage is that the apparatus 20 can be adjusted in a simple and fast manner from an operator by choosing the suitable diffractive element 22 and by adjusting the adjusting means 24, 25 accordingly.

In this manner, the operator can obtain a desired number of focussed laser beams 32 comprised between two and eleven spaced apart by a desired distance d from one another comprised between 30 micron and 10 mm, in particular comprised between 50 micron and 1 .3 mm.

A further advantage of the apparatus 20 is the fact that it enables the power per sheet surface units of the focussed laser beams 32 to be controlled effectively in such a manner as not to melt the cut layer 2, 6 locally and to control simultaneously the depth of the incisions 12.

Still another advantage of the apparatus 20 is the fact that, as it is able to make a plurality of incisions 12 that are very near and parallel one another (as said, even up to eleven incisions separated from one another by 30 micron), further enables possible position tolerances to be compensated between the incisions of the two mutually coupled sheets, and permits possible position tolerances of the notches 1 1 to be compensated, in such a manner as to ensure easy opening of the pouch.

Still a further advantage is that the apparatus 20 is cheap, as it can operate with a very reduced expenditure of energy (which is necessary to the laser to make the incisions 12) and does not require frequent and expensive maintenance.

Further versions and/or additions to what has been disclosed and/or to what has been shown in the attached drawings are possible.

Claims

1. Easy-opening pouch (1) formed by joining together two multilayered sheets (15) along respective edges (7, 8, 9, 10) such that said sheets (15) form the walls of said pouch (1), said multilayered sheets (15) each comprising at least one external layer (2) and one internal layer (6); said pouch (1) comprising on at least one of said sheets (15) an opening portion (14) in which at least one notch (11; 11'; 11") is made on at least one of said mutually opposite respective edges (8, 9), said pouch (1) being characterised in that a plurality of incisions (12) is provided that are substantially rectilinear, continuous and/or discontinuous, parallel to one another and made by a laser beam onto said external layer (2) and/or said internal layer (6), and in that the number of said incisions (12) and the mutual distance (d) thereof are such that said notch (11; 1 Γ; 11 ^"') is always substantially aligned on at least one incision (12) of said plurality of incisions (12).

2. Pouch according to claim 1, wherein said distance (d) is comprised between 0.03 mm and 10 mm.

3. Pouch according to claim 2, wherein said distance (d) is comprised between 0.05 mm and 1.3 mm.

4. Pouch according to claim 3, wherein said distance (d) is equal to about 0.5 mm.

5. Pouch according to any preceding claim, wherein said plurality of incisions comprises a number of incisions (12) comprised between two and eleven.

6. Pouch according to claim 5, wherein said plurality of incisions comprises a number of incisions (12) comprised between five and nine.

7. Pouch according to claim 6, wherein said plurality of incisions (12) comprises a number of incisions equal to seven.

8. Pouch according to any preceding claim, wherein said edges comprise two side edges (8, 9), an upper edge (10) and a bottom edge (7); said opening portion (14) being defined near said upper edge (10).

9. Pouch according to claim 8, wherein on each of said side edges (8, 9) at said opening portion (14) a notch (11; 11 '; 11" ) is obtained in a tolerance zone (T) of said side edges (8, 9) in such a manner that said notches (11; 1Γ; 11 ') are substantially aligned on one another.

10. Pouch according to claim 9, wherein said plurality of incisions (12) extends in said opening portion (14) between said notches (11; 1Γ; 1 ) substantially parallel to said upper edge (10) and to said bottom edge (7).

1 1. Pouch according to any preceding claim, wherein said incisions (12) have a maximum depth that is equal to the thickness of said external layer (2) and/or of said internal layer (6).

12. Pouch according to any preceding claim, wherein said plurality of incisions ( 12) and said at least one notch ( 1 1 ; 1 Γ; 1 1 ") are made in the respective opening portion ( 14) of said two multilayered sheet ( 15) joined together to form said easy- opening pouch ( 1 ).

13. Pouch according to any preceding claim, wherein said internal layer (6) is made of a material provided with great stiffness, chosen in a group comprising: polyester, PVC, cellophane, polystyrene, polycarbonate, various types of mono-axially oriented and bi-axially oriented polypropylene, various types of mono-axially oriented and bi-axially oriented polyethylene in which the orientation of the chains of molecules in at least one direction is substantially parallel to the direction defined by said upper edge ( 10).

14. Apparatus (20) for making a plurality of incisions (12) on one or more layers (2, 6) of a sheet of multilayered material ( 15) comprising:

an optical unit (21 ) provided with diffractive means (28) arranged for dividing a main laser beam (30) entering said optical unit (21 ) into a plurality of laser beams (31 );

a focussing unit (26) provided with one or more lenses (27) arranged for focussing said plurality of laser beams (3 1 ) entering said focussing unit (26) to obtain a plurality of focussed beams (32);

characterised in that said optical unit (21 ) comprises adjusting means (24) acting on the arrangement of said diffractive means (28) in such a manner as to vary a reciprocal distance between said plurality of laser beams (31 ) exiting said optical unit (21 ).

15. Apparatus according to claim 14, wherein said adjusting means (24) comprises an adjustable element (25) provided with a graduated reading scale that can be rotated to adjust said mutual distance.

16. Apparatus according to claim 14, or 15, wherein said diffractive means (28) is associated with a diffractive element (22) of said optical unit (21 ) that is removably received in a housing (23) made in said optical unit (21 ).

17. Apparatus according to claim 16, wherein said optical unit (21 ) comprises a plurality of said diffractive elements (22) that are interchangeable between one another, each provided with respective diffractive means (28), by replacing which it is possible to obtain the desired number of laser beams (3 1 ).

18. Apparatus according to any one of claims 14 to 17, wherein said focussing unit (26) can be moved in a direction (A) towards and away from said sheet of multilayered material (15) and/or said one or more lenses (27) can be moved and/or rotated to obtain the desired focussing of said focussed beams (32).

19. Apparatus according to any one of claims 1 1 to 18, wherein said one or more lenses have a focal length comprised between approximately 2.5 cm and 12.5 cm.

20. Apparatus according to any one of claims 14 to 19, wherein said focussing unit (26) is positioned downstream of said optical unit (21 ).

21 . Method for making a plurality of continuous incisions (12) on one or more layers (2, 6) of a sheet of multilayered material ( 15) comprising the steps of:

dividing a main laser beam (30) entering a optical unit (21 ) in a plurality of laser beams (31 ) by diffractive means (28) of said optical unit (21 );

focussing said plurality of laser beams (31 ) entering a focussing unit (26) to obtain a plurality of focussed beams (32) by one or more lenses (27) of said focussing unit (26);

cut one or more layers (2, 6) of said multilayered sheet ( 15) with said focussed beams (32);

characterised in that adjusting the arrangement of said diffractive means (28) it is provided by adjusting means (24) in such a manner as to vary a mutual distance between said plurality of laser beams (31 ) exiting said optical unit (21 ).

22. Method according to claim 21 , wherein said adjusting comprises rotating an adjustable element (25) provided with a graduated scale.

23. Method according to claim 21 , or 22, wherein replacing a diffractive element (22) of said optical unit (21 ) is provided with which said diffractive means (28) is associated with another interchangeable diffractive element (22) with which respective diffractive means (28) is associated, in such a manner as to obtain the desired number of laser beams (31 ).

24. Method according to any one of claims 21 to 23, wherein moving said focussing unit (26) in a direction (A) towards and/or away from said multilayered sheet ( 15) and/or moving and/or rotating said one or more lenses (27) to obtain the desired focussing of said focussed beams (32) is provided.