SELF-ADHESIVE LABEL VALVE

Abstract

Self-adhesive label valves are disclosed having release chimneys in correspondence of a plurality of intersection cuts in a membrane-island of film (tape) carrier (C) with cuts made in the overlying self-adhesive label made of polymeric film (E) with an adhesive layer. All are inscribed within (i.e. inside) the perimeter of the membrane-island, and are destined to overlie so as to occlude pre-formed release openings in the packaging film of heatable food, and ensure in an outstandingly reliable manner a gradual release of vapors while heating, without causing an undesirable collapse of the packaging film.

Claims

1. Self-adhesive label-valve (EV), alignedly applicable on the outer surface of a flexible packaging film of heatable food for sealing one or more openings (S) in the film for discharging vapors under pressure during the heating, defined by punching a laminated multilayer of at least a tape carrier (C), from which the label-valves may be taken individually, of a polymer suitable for packaging foods, having an anti-adherent coupling surface, and of a polymeric tape (E) with a pressure activated adhesive layer on the coupling surface, said label-valve comprising an island-membrane having a size adapted to overlie and occlude said opening/openings (S) through the film of the package, the perimeter of which is defined by the punching impression of the sole tape carrier (C), and the definition perimeter of the self-adhesive label around the geometrical projection of the area of the underlying island-membrane is defined by the punching impression of the sole polymeric tape (E) with adhesive layer together with one or more cuts, wherein said cuts are inscribed in the perimeter of the geometrical projection of the area of said underlying island-membrane; and at least one or more cuts are defined by the punching impression of the sole tape or film carrier (C) inside the definition perimeter of the island-membrane and intersect the geometrical projection of said cut/cuts of the overlying tape or film (E) with adhesive layer.

2. Self-adhesive label-valve (EV) according to claim 1, wherein said cut or cuts defined by the punching impression of said island-membrane of tape or film carrier (C) intersecting the geometrical projection of said cut or cuts (3) of the above tape or film (E) with layer of adhesive, do not intersect any release opening (S) through the underlying film of the package.

3. Self-adhesive label-valve (EV) according to claim 1, further comprising a plurality of cuts, proofs of tampering, through the tape or film with adhesive layer (E) in a geometric area bordered by the perimeter of the label-valve and by the perimeter of the underlying island-membrane of tape or film carrier.

4. Self-adhesive label-valve (EV) of claim 1, wherein said tape carrier (C) is of a material selected from to the group consisting of polypropylene having a thickness of between 35 and 60 m, polyester having a thickness of between 25 and 45 m and paper of a thickness of between 20 and 500 m, with a coupling surface of the film or tape carrier (C) treated with a silicone based material.

5. Self-adhesive label-valve (EV) of claim 1, wherein said tape (E) of polymer suitable for packaging food having on the coupling surface a layer of pressure activated adhesive, is made of a material selected from the group consisting of polypropylene having a thickness of between 35 and 60 m, polyester having a thickness of between 25 and 45 m and laminated multilayers of one or both materials with a film of polyamide or Evoh having a thickness of between 10 and 20 m.

6. Self-adhesive label-valve (EV) of claim 1, wherein said pressure activated adhesive is a water based acrylic or with an organic or silicone solvent adhesive.

Description

[0015] FIG. 1 shows in a schematic way the application of self-adhesive valve labels of the present invention onto a film for packaging products in heat-sealed packages.

[0016] FIG. 2 illustrates an example of the geometric coordination of the cuts made respectively on the tape or sheet carrier and on the self-adhesive tape or sheet and intersecting with each other, according to the present invention.

[0017] FIG. 3 shows an alternative example of the layout of the cuts intersecting in the anti-adherent island-membrane and in the overlying self-adhesive material of the label-valve.

[0018] FIGS. 4 to 11 show alternative layout examples of the cuts intersecting respectively formed in the anti-adherent island-membrane and in the overlying self-adhesive material of the label-valve, and their coordination with respect to the footprints of the release openings pre-formed in an underlying film packaging products heated in heat-sealed packages.

[0019] Referring to the figures, the island-membrane 4 of the anti-adherent film carrier C of the multilayer film subjected to punching from a first side and after from the opposite side according to the process illustrated in the prior Italian Patent No 1394981 in the name of the same applicant, may be of a material belonging to the group composed of polypropylene (for example of a thickness comprised between about 35 and 60 m), polyester (for example of a thickness comprised between about 25 and 45 m), polymeric materials with equivalent characteristics or paper of a thickness comprised between 20 and 500 m. The coupling surface of the tape carrier C from which the label-valve EV having the island-membrane 4 defined by punching the same tape carrier C, is commonly treated with silicone for determining its anti-adherence properties. The film E with pressure-activated adhesive layer of the laminated multilayer, in which the adhesive labels are defined by punching may be of a material belonging to the group composed of polypropylene (PPE) (for example of a thickness comprised between 35 and 65 m), polyester (PET) (for example of a thickness comprised between about 25 and 45 m or of another material with equivalent properties), or laminated multilayers of the same plastic materials or of one of them with a film of polyamide (of a thickness comprised for example between 10 and 20 m), or a laminated multilayer PE-Evoh-PE.

[0020] The layer of adhesive applied on the coupling face of the film E for defining the adhesive labels of the multilayer may be a common water-based acrylic or a UV crosslinking or acrylic with organic solvent adhesive, or a silicone-based adhesive for high temperatures (up to 250 C.).

[0021] Referring to FIG. 1, the label-valves EV may be singularly taken by common holding means with suction cups, or automatically applied by means of labeling machines, by separating them from the carrier tape of anti-adherent film, each carrying therewith an island-membrane 4 of anti-adherent film C of tape carrier, defined by punching the same tape carrier, in correspondence of a relatively small area, more or less centered in respect to the definition area of the overlying label of film E, with an adhesive layer on the coupling face.

[0022] The same holding means thus apply the label-valve EV precisely (alignedly) above a pre-shaped release opening in the feed film of a machine for packaging products destined to be heated in the same sealed packaging.

[0023] In the scheme shown in FIG. 1, the release opening pre-shaped in the packaging film consists of four cuts for as many circumferential arches, through which vapors under pressure generated by heating the content of the packaging could flow.

[0024] FIG. 2 shows the punching scheme of the laminated multilayer tape of anti-adherent film carrier C and of the film E with pressure-activated adhesive layer, in two distinct steps: from one side and from the opposite side of the laminated multilayer.

[0025] The anti-adherent film carrier C of the multilayer is punching according to the engraving impression shown at the left, defining an island-membrane 4 of an anti-adherent film carrier C that in the shown example has a circular perimeter, and an inner cut 6 i.e. inscribed in the circular perimeter of definition of the island-membrane 4.

[0026] The film E with the pressure activated adhesive layer is punched according to the engraving impression shown at the side of the first impression, defining the perimeter 2 of definition of the self-adhesive label of film E with the pressure activated adhesive layer, that in the example has a squared perimeter, and two inclined cuts 3 that by superposition are inscribed in (internal) the geometrical projection of the definition perimeter of the undelaying island-membrane 4 of anti-adherent film carrier C, and intersect the cut 6 in two points.

[0027] Optionally, in the sole film E also cuts 5 may be made along the definition perimeter as shown or, as an alternative, short arched cuts distributed along the perimetric region may be made, so as to constitute effective integrity proofs (because they cause irreversible distortions of the adhesive label in case of tampering).

[0028] FIG. 3 shows another exemplary layout of the respective punched impressions of the anti-adherent film carrier C and of the film E with a pressure activated adhesive layer of the tape of laminated multilayer.

[0029] In this embodiment two points of intersection between cuts, respectively in the self-adhesive film E of the self-adhesive label-valve EV and in the underlying island-membrane 4 of anti-adherent film carrier C, are realized by intersection of pairs of cuts formed through the respective films E and C.

[0030] Figures from 4 to 11 show alternative exemplary layouts of intersecting cuts, through which effective release chimneys are made for vapors under pressure formed in the island-membrane 4 of anti-adherent film carrier C and in the overlying self-adhesive film E of the label-valve EV, and their disposition in respect to the geometrical projection of release openings S, pre-shaped in an underlying film for packaging products that may be heated in thermo-sealed packages.

[0031] Preferably, the cut or cuts 6 formed in the island-membrane 4 of film (tape) carrier destined to overlie and shut one or more release openings present in the underlying packaging film, do not intersect any release hole or cut S made through the underlying packaging film.

[0032] The realization of these release chimneys in a plurality of intersection points of cuts 6 in the island-membrane 4 of film (tape) carrier with cuts in the overlying self-adhesive label, all inscribed (i.e. inside) in the perimeter of the island-membrane 4, ensures in an extraordinarily reliable manner the prolonged release of vapors while heating the content of the sealed packaging, without provoking an undesirable collapse of the packaging film that, by contrast, could occasionally occur with the previously used punching geometries as a consequence of a too delayed and abrupt opening of the label-valve.