Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D77/00—Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks or bags
  • B65D77/22—Details
  • B65D77/225—Pressure relief-valves incorporated in a container wall, e.g. valves comprising at least one elastic element
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B70/00—Making flexible containers, e.g. envelopes or bags
  • B31B70/74—Auxiliary operations
  • B31B70/81—Forming or attaching accessories, e.g. opening devices, closures or tear strings
  • B31B70/84—Forming or attaching means for filling or dispensing contents, e.g. valves or spouts
  • B31B70/85—Applying patches or flexible valve inserts, e.g. applying film-like valves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D1/00—Multiple-step processes for making flat articles ; Making flat articles
  • B31D1/02—Multiple-step processes for making flat articles ; Making flat articles the articles being labels or tags
  • B31D1/021—Making adhesive labels having a multilayered structure, e.g. provided on carrier webs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
  • B31D1/00—Multiple-step processes for making flat articles ; Making flat articles
  • B31D1/02—Multiple-step processes for making flat articles ; Making flat articles the articles being labels or tags
  • B31D1/026—Cutting or perforating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D2205/00—Venting means
  • B65D2205/02—Venting holes
  • B65D2205/025—Venting holes having a removable label, sticker or adhesive foil covering the hole

Definitions

• the present description relates to an adhesive valve, in particular to an adhesive and flexible valve which can be applied on incisions or openings made on airtight containers, for example containers for food to be heated, with the purpose of releasing gases which develop in them.
• the present description relates also to a sheet and a food container comprising said adhesive valve, as well as a process for manufacturing this adhesive valve or sheet.
• European patent 2275252 describes an adhesive valve which comprises a flexible label having at least one lower surface provided with an adhesive, in which a flexible membrane is applied to the lower surface of the flexible label, is completely covered by the flexible label and has a substantially non adhesive lower surface.
• One or more incisions are made in the flexible label astride the geometrical projection of the perimeter of the flexible membrane to act as exhaust valve for gases.
• the gas flow of the exhaust is very influenced by the type of adhesive used to fix the valve to the container, so that if the adhesive is too strong it will be difficult that the label lifts itself at the incisions, while if it is too weak there will be the risk that the valve does not correctly exert its closing function.
• WO 2015/111015 Al describes a similar adhesive valve, in which the flexible membrane is always completely covered by the flexible label but is provided with incisions that intersect incisions obtained in the flexible label.
• US 2927722 discloses an adhesive valve with a flexible label free of openings, so that pressurized gases must overcome the adhesive force of the label to flow outward, resulting in manufacturing, operation and reliability problems of the adhesive valve.
• adhesive valves known from these publications have a non-entirely optimal working, namely they have a release of gas bigger or smaller than the one expected according to the dimensions and the shape of the flexible label and the flexible membrane, when they are pulled or folded, in particular due to the swelling or the flexion of the sheet on which they are applied.
• Object of the present description is therefore to provide an adhesive valve free from such drawbacks. Said object is achieved with an adhesive valve, a sheet, a container and a process, whose main characteristics are specified in the claims.
• the adhesive valve allows to adjust the flow of gas through the incision in the sheet on which the adhesive valve is applied and the incision of the flexible label which releases the gases.
• the insert acts as a shutter, which slightly rises and/or is compressed in presence of gas under pressure to create a passage of gas between the incisions of the sheet and the flexible label, even when this sheet is pulled or folded.
• the adhesive valve may comprise a non-stick layer and/or a flexible membrane which improve the separation of the flexible label from the sheet in presence of gas under pressure and that can present a tapered shape in order to guide the gases towards the incision of the flexible label.
• valve and the sheet according to the present description may be fabricated with a relatively simple, inexpensive and fast process, preferably with a series production.
• Figure 1 shows a top view of a first embodiment of the adhesive valve disposed on a support
• Figure 2 shows a bottom view of the adhesive valve of Figure 1 without the support
• Figure 3 shows a top view of a sheet comprising the adhesive valve of Figure 1;
• Figure 4 shows section IV-IV of figure 3;
• Figure 6 shows the cross-section of a sheet comprising a second embodiment of the adhesive valve
• Figure 7 shows the sheet of Figure 6 during use
• Figure 8 shows the cross-section of a sheet comprising a third embodiment of the adhesive valve
• Figure 9 shows the sheet of Figure 8 during use
• Figure 10 shows a schematic view of the manufacturing process of the first embodiment of the adhesive valve
• Figure 11 shows a schematic view of the manufacturing process of the second embodiment of the adhesive valve
• Figure 12 shows a schematic view of the manufacturing process of the third embodiment of the adhesive valve
• the adhesive valve according to a first embodiment comprises in a known way at least one flexible label 1 with two surfaces and at least one lower surface la provided with adhesive. At least one flexible membrane 2 with two surfaces can be applied under the lower surface la of the flexible label 1 and in turn has a substantially non-adhesive lower surface 2a, namely a surface which is not provided with adhesive or is anyway substantially less adherent than the lower surface la of the flexible label 1 provided with adhesive.
• the upper surface of the flexible membrane 2 in contact with the lower surface la of the flexible label 1 is substantially non-adhesive.
• the flexible membrane 2 is preferably obtained through die cutting of a support 3, in sheet or tape, of the same material, which has a greater extension than the flexible label 1 and on which one or more flexible labels 1 of the same kind are applied and arranged on at least one row.
• the flexible label or labels 1 may be obtained through die cutting of a sheet or tape of greater dimensions having a surface provided with adhesive, in which the exceeding portion, namely the one which does not comprise the label or labels 1, is removed after the application of the same on the support 3.
• the flexible label 1 and the flexible membrane 2 may be obtained from a film of plastic material suitable to enter in contact with food, belonging in particular to the group composed of polypropylene (for example having a thickness comprised between 35 and 60 micron), polyester (for example having a thickness comprised between 25 and 45 micron) or plastic materials with equivalent characteristics.
• the film of the flexible label 1 may be formed from a laminate of the same plastic materials and/or from a polyamide film (with a thickness comprised between 10 and 20 micron), or a laminate PE-Evoh-PE.
• One or both surfaces of the flexible membrane 2 are treated with a material preferably compatible with a food use, which is suitable to make it non-adherent or adherent to a limited extent, in particular silicone or Vaseline oil.
• the adhesive layer applied to the lower surface la of the flexible label 1 may be a Pressure Sensitive Adhesive (PSA), in particular a water-based or UV-reticulating acrylic adhesive, an acrylic adhesive with an organic solvent or a silicone-based adhesive for high temperatures (up to 250 °C).
• PSA Pressure Sensitive Adhesive
• the flexible label 1 is shaped with at least one incision lb so as to connect the two surfaces of the flexible label 1.
• the incision lb may be linear or curved or, as in the present embodiment, closed, so as to define at least one opening, for example a substantially circular hole with a diameter not greater than 1 mm, in the flexible label 1, so that at least one portion 2c of the upper surface of the flexible membrane 2 is not covered by the flexible label 1.
• the incision lb forms a recess on the edge of the flexible label 1, so that one portion of the perimeter of the flexible label 1 passes over the flexible membrane 2 and this portion divides then the flexible membrane 2 in a portion 2c not covered by the flexible label 1 and at least one remaining portion covered by the flexible label 1.
• the area of the portion of the flexible membrane 2 covered by the flexible label is preferably larger than the area of the portion 2c of the flexible membrane 2 not covered by the flexible label 1.
• the flexible label 1 may have a substantially polygonal and/or curvilinear form, for example squared with rounded corners provided with anti -tampering cuts lc.
• the flexible label 1 extends preferably on an area x mm wide and y mm long, with x and y comprised between 20 and 30, in particular 25.
• the flexible membrane 2 preferably has a substantially polygonal and/or curvilinear shape, for example partially rectangular, namely with three substantially perpendicular sides with rounded corners and with a fourth side substantially semicircular, so that the flexible membrane 2 may have a tapered shape towards the incision lb in the flexible label 1.
• a tampered shape in the flexible membrane 2 comprises thus a substantially semicircular tapered portion joined to a non-tapered, substantially rectangular, portion.
• the flexible membrane 2 may have a different tapered shape, for example substantially pentagonal or triangular.
• the flexible membrane 2 may comprise at least one incision 2b which connects the two surfaces of the flexible membrane 2 and is covered by the flexible label 1.
• the incision 2b has in particular a closed form, so as to form for example a substantially circular opening in the flexible membrane 2.
• the incision 2b may be rectilinear or form in the flexible membrane 2 a tongue-shaped portion that may be separated from the remaining portion of the flexible membrane 2.
• the incision 2b in the flexible membrane 2 does not cross the incision lb of the flexible label 1.
• An insert 4 is arranged under the lower surface lb of the flexible label 1, between the flexible label 1 and the flexible membrane 2, so as to at least partially cover the incision 2b, namely the opening defined by this incision, of the flexible membrane 2.
• the insert 4 is solid and may be made of a substantially rigid material, for example a plastic material, with a thickness comprised between 12 and 120 micron, or a flexible and/or compressible material, for example in a non-woven fabric, with a basic weight comprised between 20 and 100 g/m 2 .
• the insert 4 may have a substantially rectangular form, for example with three sides substantially parallel to the three substantially perpendicular sides of the flexible membrane 2.
• the minimum distance d between the incision lb of the flexible label 1 and the insert 4 may be comprised between 2 and 5 mm.
• the lower surface la of the flexible label 1 may be joined to the upper surface of a sheet 5 thanks to the adhesive applied to the lower surface la, so that the flexible membrane 2 results arranged between the flexible label 1 and the sheet 5.
• the sheet 5 is in particular a sheet suitable for closing or form a food container, for example a sheet of plastic material which can be used to form a bag or be hot-welded onto the edges of a rigid tub.
• the sheet 5 comprises at least one incision 5a which connects the two surfaces of the sheet 5 and can be covered by the adhesive valve.
• the incision 5a of the sheet 5 at least partially overlaps the incision 2b of the flexible membrane 2 and/or the insert 4, so as to connect the insert 4 to the surface of the sheet 5 opposite to the adhesive valve.
• the incision 5a on the sheet 5 may be linear, curved or closed, so that the portion of the sheet 5 surrounded by the incision 5a may be removed and form an opening, for example substantially circular.
• the incision 5a in the sheet 5 can be arched, so as to form a tongue-shaped portion which can bend towards the adhesive valve or towards the opposite side.
• the flexible label 1 can adhere again to the flexible membrane 2, thereby closing the passage of gases 6 between the sheet 5 and the flexible label 1, in particular thanks to the elasticity of the materials and to electrostatic forces and/or Van der Waals forces that arise between the flexible membrane 2 and the flexible label 1.
• Figure 6 shows a second embodiment which comprises a layer 7 of a non-stick material, for example liquid silicone, applied on the sheet 5 and dried before applying the adhesive valve, which is similar to the valve of the first embodiment but does not comprise the flexible membrane 2, which is substituted by the non-stick layer 7.
• the non-stick layer 7 has substantially the same arrangement and extension of the flexible membrane 2 of the first embodiment and it is not present, namely forms an opening 7a, where the incision 5a is made in the sheet 5, so as to leave it open.
• Figure 8 shows a third embodiment which comprises a layer 8 of non-stick material, for example liquid silicone, applied to the lower surface la of the adhesive valve 1 and dried before applying the adhesive valve, which is for the rest similar to the second embodiment, namely preferably without the flexible membrane 2 and with the non-stick layer 8 which has substantially the same arrangement and extension of the flexible membrane 2 of the first embodiment.
• the insert 4 is thus arranged between the flexible label 1 and the sheet 5 and can be joined to the flexible label 1 through a portion Id of the flexible label 1 provided with adhesive and not covered by the non-stick layer 8.
• the gases 6 in the container lift and/or compress the insert 4, creating a passage between the non-stick layer 8 and the sheet 5, so that these gases 6 flow towards the outside of the container through the incision 5a of the sheet 5, the space comprised between the non-stick-layer 8 and the sheet 5 and the incision lb of the flexible label 1.
• the flexible membrane 2 of the first embodiment may be arranged like the non-stick layer 8 in the third embodiment, namely between the flexible label 1 and the insert 4.
• a tape 11 preferably wound around a bobbin 12, is pulled in the direction of the arrows by one or more first auxiliary rollers 13.
• the tape 11 comprises a first layer 14 of the same material of the flexible labels 1 mentioned above, which is joined through at least one adhesive layer to a second layer 15 of the same material of the flexible membranes 2 and the support 3 above mentioned.
• a first auxiliary roller 13 divides the first layer 14 from the second layer 15, which are pulled separately by other auxiliary rollers 13.
• the first layer 14 of the tape 11 is provided with a series of inserts 4 arranged at regular distances one after the other on the adhesive surface of the first layer 14, oriented upwards, by an applicator 16 which takes these inserts 4 from an auxiliary tape 17 released by an auxiliary bobbin 18 and then wound around another auxiliary bobbin 19.
• the first layer 14 is then provided with a series of incisions lb placed at the same regular distances between the inserts 4 by a punching machine 20, for example a laser punching machine, with the aid of a sensor 21 suitable to detect the position of an insert 4 on the first layer 14, so that the distance d between an insert 4 and the adjacent incision lb is maintained.
• the incisions lb in the first layer 14 may be made before applying the inserts 4.
• the second layer 15 of the tape 11 is provided with a series of incisions 2b by a punching machine 22, for example a laser punching machine, after which it is joined again to the first layer 14 by one or more second auxiliary rollers 23, with the inserts 4 arranged between the first layer 14 and the second layer 15.
• a punching machine 22 for example a laser punching machine
• the first layer 14 of the tape 11 is therefore die cut by a first mechanic die cutter, in particular a roller die cutter 24, to form in the first layer 14 a series of flexible labels 1 according to the present description around the inserts 4, with possible removal of the material in excess (not shown in the figure).
• the second layer 15 of the tape 11 is die cut by a second mechanical die cutter, in particular a roller die cutter 25, to form a series of flexible membranes 2 according to the present description in the second layer 15 and to form the support 3 which surrounds them.
• the tape 11 comprising the support 3 with a series of above-mentioned adhesive valves, which are formed by a flexible label 1, a flexible membrane 2 and an insert 4 arranged between the flexible label 1 and the flexible membrane 2, is thus wound around a bobbin 26.
• the tape 11 may be drawn from the bobbin 26 and used in a labeler to draw the adhesive valves arranged on this tape 11, detach them from the support 3 and apply them in above described way on at least one incision 5a of a sheet 5 which can be used to manufacture packages for food use, for examples as cover of a container in which the sheet 5 is joined onto the edge of this container, in particular through adhesive or heat-sealing.
• a first layer 31 of the same material of the adhesive layer 1 is drawn from a bobbin 32 and provided with adhesive by an applicator 33, for example a spray applicator.
• the first layer 31 may already be provided with an adhesive surface protected by a non-stick layer which is removed before use.
• the first layer 31 is then provided with a series of inserts 4 and of incisions lb arranged at regular distances one after the other, as in the first embodiment.
• a sheet 5 is drawn from a bobbin 34 and is provided with a series on non-stick layers 7 at regular distances by an applicator 35, for example a spray applicator, and with a series of incisions 5a by a punching machine 36, for example a laser punching machine.
• the sheet 5 is thus joined again to the first layer 31 by one or more second auxiliary rollers 37, with the inserts 4 arranged between the first layer 31 and the sheet 5.
• the first layer 31 is thus die cut by a first mechanical die cutter, in particular a roller mechanical die cutter 38, to form in the first layer 31 a series of flexible labels 1 according to the present description around the inserts 4, with possible removal of the material in excess (not shown in the figure).
• the sheet 5 comprising a series of above- mentioned adhesive valves, which are formed by a flexible label 1, a non-stick layer 7 and an insert 4 arranged between the flexible label 1 and the sheet 5, is then wound around a bobbin 39.
• the sheet 5 may be drawn from the bobbin 39 and used for example to manufacture packages for food use.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Preparation And Processing Of Foods (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (2)

Cited By (2)

Citations (5)

• 2017
  • 2017-05-22 IT IT102017000055238A patent/IT201700055238A1/it unknown
• 2018
  • 2018-05-18 WO PCT/IB2018/053526 patent/WO2018215900A1/en active Application Filing

Patent Citations (5)

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