TECHNICAL FIELD The present description relates to a laminated material for packaging, in particular for food use. The present description also relates to a process for manufacturing such a laminated material.

FRAMEWORK OF THE DESCRIPTION

A known laminated material is provided with two layers of plastic material joined by a pressure adhesive also known as PSA (Pressure-Sensitive Adhesive), which adhesive allows the separation of a tongue obtained by cutting one of the two layers.

Such laminated material can be used to close a container, as for example described in WO 2015/145338 Al, and be provided with an incision also made in the second layer by means of a laser die-cutter, in which case it is necessary to use a layer which is optically opaque to the laser to avoid making the same incision in both materials. However, such an opaque layer prevents a product contained in a packaging formed by this material from being seen through the laminated material.

US 2005/276525 Al and WO 2011/032064 Al disclose a laminated material according to the preamble of claim 4, which may be tampered by malicious persons who want to open the opening formed in the layers of the laminated material, remove part of the product contained in a packaging comprising the laminated material and closing this opening.

SUMMARY OF THE DESCRIPTION

Object of the present description is therefore to provide a laminated material free from such drawbacks of US 2005/276525 Al and WO 2011/032064 Al . Said object is achieved with a laminated material and a manufacturing process whose main characteristics are specified in the attached claims. Thanks to the particular shape and mutual arrangement of the incisions made in the two layers, the laminated material according to the present description can be advantageously used for food packaging which can be easily opened and closed, even several times, during use. Moreover, during the first opening of such a packaging, the portion of material laminated near the interruption of the second incision is torn in a controlled manner, so as to show openings due to possible tampering of the packaging itself.

In particular, such openings are obtained by means of mechanical die-cutters, so as to be able to employ substantially transparent layers which allow the vision of a product through the resulting laminated material .

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features of the laminated material and of the process according to the present description will become evident to those skilled in the art from the following detailed and non-limiting description of an embodiment thereof with reference to the attached drawings in which:

- Figure 1 shows a top view of the laminated material;

- Figure 2 shows detail II of Figure 1;

- Figure 3 shows a rear view of the detail of Figure 2;

- Figure 4 shows the enlarged section IV-IV of Figure 3;

- Figure 5 shows a schematic view of the process for manufacturing the laminated material of Figure 1. EXEMPLARY EMBODFMENTS

With reference to Figures 1 to 4, it is seen that the laminated material according to the present description comprises at least one first layer 1 or outer layer, which is suitable to be directed towards the outside of a packaging, for example a bag or a tub (not shown in the figures). The first layer 1 is joined to at least one second layer 2 or inner layer, suitable to be facing the packaging, by means of at least one adhesive layer 3 arranged between the layers 1, 2, so as to form a sheet of laminated material, preferably continuous to be wound on a roll. The width and/or the length of the first layer 1 are substantially equal respectively to the width and/or the length of the second layer 2. The first layer 1 and/or the second layer 2 preferably comprise at least one film of plastic material, for example polypropylene, having a thickness comprised between 10 and 40 microns, while the adhesive 3 is preferably a pressure adhesive which allows both the separation of the first layer 1 from the second layer 2 by manual traction and their subsequent adhesion by pressing the first layer 1 on the second layer 2, and/or vice versa. Preferably, the first layer 1, the second layer 2 and the adhesive 3 are substantially transparent, so that the resulting laminated material is substantially transparent.

At least one first tongue-shaped incision 4, in particular U-shaped or V-shaped, is formed in the first layer 1, so as to form in the first layer 1 a tongue-shaped portion la which can be separated from the second layer 2 while keeping the remaining portion lb of the first layer 1 joined to the second layer 2. At least one end of the first incision 4 is provided with a curl 5.

A portion lc (shown with dashed lines in Figures 1 to 3) of the first layer 1 which is not in contact with the adhesive layer 3 is arranged around at least one portion of the first incision 4 of the first layer 1, in particular a portion of the first layer 1 corresponding to the tip of the tongue-shaped portion la. Such portion lc can be made by not applying the adhesive 3 in the region 6 between the two layers 1, 2 corresponding to this portion, as in the present embodiment, or by arranging a septum (not shown in the figures) having the same contour of this region 6 or of the portion lc between the first layer 1 and the adhesive layer 3. Such portion lc has, for example, a substantially semicircular or lunette shape, preferably with at least one peninsula Id facing the tip of the first incision 4, namely of the tongue-shaped portion la. Said peninsula Id is thus in contact with the adhesive 3 and helps to keep the tip of the tongue-shaped portion la of the first layer 1 joined to the second layer 2, despite the portion lc without adhesive of the first layer 1. At least one second tongue-shaped incision 7, in particular U-shaped or V-shaped, is formed in the second layer 2, so as to form in the second layer 2 a tongue-shaped portion 2a which can be separated from the second layer 2 while keeping joined to the first layer 1 the remaining portion 2b of the second layer 2. At least one end of the second incision 7 is provided with a curl 8. The second incision 7 is separated from the portion lc of the first layer 1 which is not in contact with the layer of adhesive 3.

The second incision 7 is surrounded at least partially by the first incision 4, and/or the tongue-shaped portion la of the first layer 1 completely encloses the tongue-shaped portion 2a of the second layer 2, and/or the tips of the tongue-shaped portions la, 2a of the layers 1, 2 are oriented in the same direction D, which also acts as a symmetry axis for these portions la, 2a, and/or the ends of the first incision 4 and of the second incision 7 are arranged along axes Al, A2 substantially parallel to each other and/or substantially perpendicular to said direction D.

The second incision 7 has at least one interruption 9, in particular at the tip of the tongue-shaped portion 2a, where the incision 7 has two substantially rectilinear portions 7a which extend towards the inside of the tongue-shaped portion 2a. A third incision 10, concave-shaped towards the tip of the tongue-shaped portion 2a, is preferably arranged beside the free ends of the two portions 7a of the second incision 7, in a substantially transverse position with respect to these portions 7a.

Figure 4 shows also the tongue-shaped portion la of the first layer 1, which, when pulled by a user, separates from the remaining portion lb of the first layer 1 and carries with itself the tongue-shaped portion 2b of the second layer 2, which is joined by the adhesive 3 to the portion la of the first layer 1. During this separation the portion of the second layer 2 arranged between the ends of the substantially rectilinear portions 7a and the third incision 10 is torn, so as to act as a tamper indicator.

Referring to Figure 5, it is seen that in a first operating step of the manufacturing process the first layer 1 preferably wound on a first roller 11 is pulled in the direction of the arrows towards one or more first auxiliary rollers 12 which apply on one side of the first layer 1 the adhesive layer 3 taken by a first auxiliary roller 12 from a tank 13. The first auxiliary roller 12 which takes the adhesive 3 from the tank 13 has a cavity having a shape corresponding to the shape of the portion lc of the first layer 1 which is not in contact with the adhesive 3. In alternative embodiments, the adhesive 3 can be applied by a rotogravure or flexographic process, with devices and methods similar to those used for rotogravure or flexographic printing.

The first layer 1 provided with adhesive 3 is then joined to the second layer 2, preferably wound on a second roller 14, by second auxiliary rollers 15, so as to obtain a laminated material 16 which can be wound on a third roller 17. Before being wound on the third roller 17, at least one mechanical die-cutter, in particular a roller die-cutter 18, forms the first incision 4 in the first layer 1 and/or the second incision 7 in the second layer 2. The roller die-cutter 18 can also form the third incision 10 in the second layer 2, as well as further first, second and third incisions.

In a subsequent step, not shown in the figures, the laminated material 16 can be taken from the third roller 17 and cut to obtain a plurality of sheets, each provided at least with first and second incisions, which can be used to make packaging for food, for example as a cover of a container in which the second layer 2 is joined to the edge of this container, in particular by adhesive or heat-sealing.

Any variations or additions may be made by those skilled in the art to the embodiment described and illustrated herein while remaining within the scope of the following claims. In particular, further embodiments may include the technical features of one of the following claims with the addition of one or more technical features described in the text or illustrated in the drawings, taken singularly or in any mutual combination.