Reclosable Packaging
20180170642 ยท 2018-06-21
Inventors
Cpc classification
B65D75/5838
PERFORMING OPERATIONS; TRANSPORTING
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
International classification
B65D75/58
PERFORMING OPERATIONS; TRANSPORTING
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
B65D77/20
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The present invention is related to a reclosable packaging container comprising a flexible laminate with a build-in opening and reclose feature in the form of a flap, said laminate comprising an inner structure and an outer structure adhesively joined face-to-face by a permanent adhesive, a pattern of pressure-sensitive adhesive being integrated between said inner structure and said outer structure, the pressure-sensitive adhesive being entirely covered by the permanent adhesive, a marginal region delineated by inner and outer score lines comprises the pressure-sensitive adhesive overlaying the permanent adhesive in an imprint region of reduced permanent adhesive thickness, the cumulative thicknesses of the pressure-sensitive adhesive and of the permanent adhesive in the imprint region being substantially the same as the thickness of the permanent adhesive outside this region.
Claims
1. A reclosable packaging container comprising a flexible laminate with a build-in opening and reclose feature (1), said laminate comprising an inner structure (9) and an outer (8) structure, adhesively joined face-to-face by a permanent adhesive (3), a pattern of pressure-sensitive adhesive (2) being integrated between said inner (9) and outer (8) structures, the pressure-sensitive adhesive (2) being entirely covered by the permanent adhesive (3), the outer structure (8) forming the outer surface of the container and the inner structure (9) forming the inner surface of the container, the outer structure (8) comprising an outer flap portion delimited by a scoring line (5) through the outer structure, and an inner structure comprising an inner flap portion delimited by a scoring line (6) through the inner structure, the inner score line (6) and the outer score line (5) creating an opening into the container when the flap portions are peeled back, a marginal region (25) of the outer flap portion extending beyond an edge of the inner flap portion and overlying an underlying surface of the inner structure (9), the inner and outer flap portions being joined with the permanent adhesive (3) and the pressure-sensitive adhesive (2) being disposed between the marginal region (25) of the outer flap portion and the underlying surface of the inner structure (9) for attaching and re-attaching, in use, the outer flap portion to the underlying surface, the permanent adhesive (3) comprising one or more imprints (24) reducing the thickness of the permanent adhesive (3) in the region where the pattern of pressure-sensitive adhesive (2) is located, the added thicknesses of the pressure-sensitive adhesive (2) and of the permanent adhesive (3) in the imprint region (24) being substantially the same as the thickness of the permanent adhesive (3) outside the imprint region (24).
2. The reclosable packaging container as in claim 1, wherein one of the inner or outer structures (8,9) of the laminate additionally comprises a pattern of release coating (4) in an opening-initiation zone (7) adjacent to the pressure-sensitive adhesive pattern (2), said release coating (4) being entirely covered by the permanent adhesive (3) within the imprint region (24) of permanent adhesive (3), the added thicknesses of the release coating (4) and of the permanent adhesive (3) in the imprint region (24) being substantially the same as the thickness of the permanent adhesive (3) outside the imprint region (24).
3. The reclosable packaging container as in claim 2, wherein the release-coating layer (4) is thinner than the pattern-applied pressure-sensitive adhesive (2).
4. The reclosable packaging container as claim 1, wherein one of the outer or inner structures (8,9) has a greater affinity for bonding to the pressure-sensitive adhesive (2) such that the pressure-sensitive adhesive (2) remain entirely with one of the outer or inner structures (8,9) when the flap portions are peeled back.
5. The reclosable packaging container as in claim 1, wherein the longitudinal edges of the outer structure (8) substantially coincide with the longitudinal edges of the inner structure (9).
6. The reclosable packaging container as in claim 1, wherein the outer structure (8) includes a layer that is reverse-printed on a surface of the layer facing the inner structure (9).
7. The reclosable packaging container as in claim 1, wherein the inner structure (9) includes a layer of heat-sealable material (20).
8. The reclosable packaging container as in claim 1, wherein the inner structure (9) includes a barrier layer (10) providing a barrier against passage of at least one of moisture and oxygen.
9. The reclosable packaging container as in claim 8, wherein the barrier layer (10) comprises a metallized polymer film (21).
10. The reclosable packaging container as in claim 1, wherein the outer structure (8) comprises a layer of polyethylene terephthalate and the inner structure (9) comprises a multi-layer web comprising a metallized polymer film (21) and a polymeric sealant layer.
11. The reclosable packaging container as in claim 10, wherein the metallized polymer film (21) comprises metallized oriented polypropylene.
12. The reclosable packaging container as in claim 1, wherein the flexible laminate with a build-in opening and reclose feature (1) is a lid.
13. A method for making the flexible laminate of the packaging container as in claim 1, said laminate having a built-in opening and reclose feature (1), said method comprising the steps of: pattern-applying a pressure-sensitive adhesive (2) onto one surface of the inner or outer structure (8,9); applying a permanent adhesive (3) onto the entire surface of the inner or outer structure (8,9), the layer of permanent adhesive (3) comprising one or more imprints (24) where the permanent adhesive (3) has a lower thickness for the location of the pressure-sensitive adhesive pattern (2), the added thicknesses of the pressure-sensitive adhesive (2) and of the permanent adhesive (3) in the imprint region (24) being substantially the same as the thickness of the permanent adhesive (3) outside the imprint region (24); scoring the inner and outer structures (8,9) by a scoring station (15) before or after adhesively joining the inner structure (9) to the outer structure (8) face to face via the permanent adhesive (3) to form the laminate, an outer score line (5) being formed through the thickness of the outer structure (8) in registration with the outer perimeter of the pressure-sensitive adhesive (2), and an inner score line (6) being formed through the thickness of the inner structure (9) in registration with the inner perimeter of the pressure-sensitive adhesive (2), the marginal region (25) of the outer opening portion between the outer and inner score lines (5,6) being attached to an underlying surface of the inner structure (9) via the pressure-sensitive (2).
14. The method as in claim 13, comprising the additional step of pattern-applying a release coating (4) in an opening-initiation zone (7) adjacent to the pressure-sensitive adhesive pattern (2) on one of the outer or inner structures (8,9), said release coating (4) being entirely covered by the permanent adhesive (3) within the imprint region (24), the added thicknesses of the release coating (4) and of the permanent adhesive (3) in the imprint region (24) being substantially the same as the thickness of the permanent adhesive (3) outside the imprint region (24).
15. The method as in claim 13, further comprising the step of treating one surface of the outer or inner structure (8,9) with a corona or flame treatment to increase the bonding affinity with the pressure-sensitive adhesive (2) such that the pressure-sensitive adhesive (2) tends to remain adhered to the treated surface when the opening portions are peeled back.
16. The method as in claim 13, wherein the inner structure (9) comprises a continuous web drawn from a first supply roll and wherein the outer structure (8) comprises a continuous web drawn from a second supply roll, the inner structure (9) being advanced to adhesive and optionally release-coating application stations (16,17,18) where the permanent adhesive layer (3) is applied on the entire surface, the layer of permanent adhesive (3) comprising imprint regions (24) for the location of the pressure-sensitive adhesive (2) and optionally the release coating (4), the pressure-sensitive adhesive (2) and optionally the release coating (4) then being applied on the imprint regions (24), the inner and outer structures (8,9) are then adhesively joined in the laminating station (13).
17. The method as in any of claim 13, wherein the adhesive and optionally release-coating layer application stations (16,17,18) apply layer of permanent adhesive (3) comprising imprints (24) in register with said pressure-sensitive adhesive pattern (2) and optionally release-coating pattern (4) in a recurring design spaced apart along a length of the inner or the outer structure (8,9) by an index distance substantially corresponding to a package dimension of the packaging container to be produced with the packaging laminate.
18. The method as in claim 17, wherein the scoring station (15) forms the score lines at intervals spaced apart along the outer and inner structure, or along the laminate by said index distance.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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KEY
[0054] 1. Build-in opening and reclose feature [0055] 2. Pattern-applied pressure-sensitive adhesive (PSA) [0056] 3. Permanent adhesive (PA) [0057] 4. Release-coating layer for the opening initiation [0058] 5. Scoring line of the outer structure [0059] 6. Scoring line of the inner structure [0060] 7. Opening initiation (dead zone) [0061] 8. Outer structure of the laminate [0062] 9. Inner structure of the laminate [0063] 10. Barrier layer [0064] 11. Seal layer [0065] 12. Printed layer [0066] 13. Lamination station [0067] 14. Oven [0068] 15. Scoring station (laser, kiss cutting . . . ) with eye mark/scoring coordination [0069] 16. PSA applicator [0070] 17. PA applicator [0071] 18. Release layer applicator [0072] 19. Support film [0073] 20. Heat sealable material (lacquer or sealable polymer) [0074] 21. Metallized polymer film [0075] 22. Metal foil [0076] 23. Ink [0077] 24. Imprint region [0078] 25. Marginal region
DESCRIPTION OF THE INVENTION
[0079] The present invention discloses a flexible packaging container formed by a laminate having a built-in opening and reclose feature 1, the laminate comprising a two-part structure, namely an outer structure 8 joined in face-to-face relation with an inner structure 9. The adjectives inner and outer are related to the position in the packaging container, the inner structure 9 being in contact with the content of the packaging container and the outer structure 8 being in contact with the environment. Inner and outer structures can also be named first and second structures of the laminate.
[0080] At least one of both structures (8,9) comprises a pattern-applied pressure-sensitive adhesive 2 and a permanent adhesive 3 on its entire surface. Once both structures (8,9) are joined by lamination, the patterned pressure-sensitive adhesive 3 is entirely covered by the permanent adhesive 3. In the region covered by both adhesives, the pressure-sensitive adhesive 2 overlays a thinner layer of permanent adhesive 3, said permanent adhesive layer 3 comprising an imprint 24 in order to avoid an extra thickness in this specific region. The global thickness of the PSA 2 added to the thickness of the permanent adhesive 3 is substantially the same as the thickness of the permanent adhesive 3 outside the PSA pattern region (outside the imprint region 24). This avoids the formation of a bump on the reel of laminate.
[0081] The inner and outer structures (8,9) of the laminate includes usual lamination structures. The outer structure generally exhibits a printable polymer layer, sometimes associated to a paper layer. Reverse printing is often preferred. Barrier layer 10 such as oriented polyamide (OPA) or EVOH, aluminium foils and the like are usual constituents. The inner structure 9 often comprises a polyolefin seal layer, sometimes associated to support layer, among them oriented polymers like OPP, OPA, OPET, . . . . Substantially all combinations are possible and well known by those skilled in the art.
[0082] The number of constituents of a laminate are mainly governed by their specific function in the laminate, by lamination facilities and by price considerations. Technically, almost all combinations are possible.
[0083] A score line, defined here as a line of weakness or a trough cut, is formed in the outer structure (outer score line 5) to define an outer opening portion and an inner line of weakness or a trough cut is formed in the inner structure (inner score line 6) to define an inner opening portion. The outer and inner opening portions are attached to each other by a permanent adhesive 3, except in the marginal region 25 that extends beyond the peripheral edge of the inner opening portion between the outer and inner cut or weakening lines, where a PSA pattern is applied and superposed on the thinner permanent adhesive within an imprint 24.
[0084] Since the permanent adhesive 3 covers the entire surface of one of the outer or inner structures (8,9), the PSA pattern 2 is covered by the permanent adhesive 3. In the region where the PSA 2 is pattern applied and optionally the release-coating layer 4 is applied, the permanent adhesive comprises an imprint wherein the thickness of the permanent adhesive is reduced in order to avoid an extra thickness in this specific region. The thickness of the PSA 2 added to the thickness of the permanent adhesive 3 is substantially the same as the thickness of the permanent adhesive 3 outside the PSA pattern zone and outside the optional release-coating zone. As shown in
[0085] As far as the outer and inner opening portions are connected by a permanent adhesive 3, they can be lifted out of the plane of the build-in opening as a flap, thereby creating an opening through the packaging structure defined by the inner line of weakness (see
[0086] After a first opening, the flap created by the connection of the inner and outer portions can be reclosed by adhering the marginal region 25 of the outer opening portion to the underlying portion of the inner structure 9 via the pressure-sensitive adhesive 2. This pressure-sensitive adhesive 2 can be positioned on the outer or the inner structure (8,9), both positions having their advantages and drawbacks. Positioned on the inner structure 9, the PSA is often rapidly contaminated by the content of the package, such as confectionary articles or biscuits, etc. Positioned on the outer structure 8, the PSA 2 is possibly passivized by finger contact. The choice of the position of the PSA 2 is therefore conditioned by the content of the packaging and the requirements of the end-user.
[0087] The manufacturing processes of the present invention are shown in
[0088] In one embodiment of the invention depicted in
[0089] In another embodiment of the invention depicted in
[0090] In an additional embodiment depicted in
[0091] The outer and inner structures (8,9) are preferably supplied from rolls and have substantially the same width. Once laminated face to face, both structures form a laminate that is a continuous web to be supplied to the final packaging station.
[0092] One or both of the inner and outer structures (8,9) or the adhesively assembled laminate are then scored at a scoring station 15 where an outer score line 5 is formed through the thickness of the outer structure 8 in registration with the outer perimeter of the pattern-applied pressure-sensitive adhesive 2 and possibly release-coating layer 4 if an opening initiation 7 is present, and an inner score line 6 is formed through the thickness of the inner structure 9 in registration with the inner perimeter of the pressure-sensitive adhesive layer 2. The score lines (5,6) can be formed by laser scoring, die cutting or kiss cutting, or any other available method well-known in the art. Various scoring positions are disclosed in
[0093] To maintain the outer and inner score lines (5,6) in registration around the PSA and release layer pattern (outer and inner perimeters of both), the scoring operation is synchronized with the advancement of the laminate by means of an optical sensor detecting an eye mark sequence on the laminate, whose location in relation to the pressure-sensitive adhesive 2 and release-coating layer 4 pattern is known.
[0094] In case of laser cutting, the depth and width of the score line can be adjusted by regulating the power output of the beam and the residence time of a given spot on the film surface. These parameters are selected in combination with the material to be scored. Some materials are more receptive than others to laser energysee for instance U.S. Pat. No. 3,909,582 and U.S. Pat. No. 5,158,499 giving extensive information on laser-cutting technology.
[0095] Furthermore, various combinations of mechanical and laser scoring are possible. One possibility is for instance to laser-score one side of the laminate and to mechanically cut the other side if one of both structures is not laser-scorable, for instance in the case of a non-absorbing seal layer, such as polyethylene without reflective barrier layer behind.
[0096] The adhesives can be applied using any suitable equipment and technique known in the art such as gravure roll for instance. Since the permanent adhesive 3 is applied on the entire surface of at least one part of the laminate, the thickness of the permanent adhesive 3 in the location of the pressure-sensitive adhesive 2 and the release-coating layer 4 is lower than the thickness of permanent adhesive 3 outside the PSA 2 and release-coating layer 4. This thinner part of the permanent adhesive 3 defines an imprint 24. The imprint 24 is located in such a manner that the thickness of the superposed PSA 2/release-coating layer 4 and permanent adhesive 3 remains substantially the same as the thickness of the permanent adhesive 3 outside the location of the PSA 2 and release-coating layer 4 pattern.
[0097] In the final laminate, the outer opening portion bonded by the permanent adhesive 3 to the inner opening portion is peelable from the underlying surface of the inner structure 9 allowing both portions to be peeled back and to create a reclosable opening. The marginal region 24 formed between the outer and inner score lines (5,6) on the outer opening portion, is re-attachable to an underlying surface of the inner structure 9 by the pressure-sensitive adhesive 2.
[0098] The inner structure 9 of the laminate comprises one or more of a sealant or support layer(s) (19,20) forming the inner surface of the laminate. Sealant layers are well known in the art and comprise heat-seal material such as heat-seal lacquer, LDPE, HDPE, EVA, polypropylene, polyolefin copolymers in general, ionomers or cold-seal materials.
[0099] The inner and outer structures (8,9) can also comprise one or more barrier layer(s) 10 known in the art such as metallized polyolefin films, for instance metallized oriented polypropylene (oPP), ethylene vinyl alcohol copolymer (EVOH), oriented polyamide (oPA). Other possibilities are ceramic-coated films like AlOx or SiOxcoated polymer films or aluminium foil.
[0100] The outer structure comprises one or more of the following layers: [0101] oriented polypropylene (oPP, 15-40 m); [0102] high-density polyethylene (HDPE, 15 to 40 m); [0103] polystyrene (PS, 15-40 m); [0104] oriented polyamide (oPA, 10-40 m); [0105] polyester such as polyethylene terephthalate (PET, 10 to 40 m); [0106] paper.
The outer layer of the outer structure 8 can be printed outside or reverse-printed.
[0107] All the layers of the inside or outside structures (8,9) can be laminated by means of adhesives or coextruded with possible tie layer if necessary. The methods for all possible combinations are known in the art. Some of the preferred structures are represented in
[0108] In the lamination process, the outer structure 8 is provided from a supply roll to a print station for printing graphics and/or indicia on it (not shown). This can be achieved by means of a rotogravure printer. In a preferred embodiment of the invention, the outer structure 8 includes a transparent PET layer that is reverse-printed, which means that the inks are applied to the surface of the PET layer, which is subsequently laminated to another structure, the inks are visible through the first structure by transparency (see
[0109] The surface of the outer structure 8 can be treated by corona discharge or flame treatment just prior to printing in the print station or even in an earlier production step. The corona treatment is typically used in the art to render the surface more receptive to the inks and/or to increase the affinity of the surface to the pressure-sensitive adhesive 2 and to the release-coating layer 4 that is subsequently pattern-applied to the surface (see
[0110] After the optional corona and printing operation, the inner and outer structures (8,9) are submitted to application stations of permanent adhesive 3, pressure-sensitive adhesive 2 and release coating 4 in various orders depending on the chosen embodiments.
[0111] The embodiment described in
[0112] The embodiment described in
[0113] The embodiment described in
[0114] All possible applying combinations can of course be contemplated for the permanent adhesive 3, pressure-sensitive adhesive 2 and release-coating layer 4. Instead of applying the release-coating layer 4 and PSA pattern 2 on the inner structure 9, they could be applied to the outer structure 8 and the permanent adhesive on the inner structure 9. All of them could also be applied to the outer structure 8. The chosen option is irrelevant as long as no extra thickness is created by the overlapping of the PSA/release layer and the permanent adhesive imprint 24. An extra thickness would lead to an undesirable bump or mark on the reel of laminate.
[0115] Pressure-sensitive adhesives 2 are also called permanent tacky adhesives and are well known in the art. Pressure-sensitive adhesives 2 can globally be based on latex emulsions (natural rubber, chloroprene, butyl, polybutadiene, isoprene, neoprene . . . ). They can also comprise acrylic adhesives, styrene copolymers (SIS/SBS) and others . . . . Pressure-sensitive adhesives form viscoelastic bonds that are permanently tacky and adhere under simple finger pressure.
[0116] The adhesive and release-coating layer 4 applying stations (16,17,18) are complemented by drying means such as ovens or infra-red heater for instance, allowing the applied adhesives to be in good condition for the next manufacture step (lamination or additional application of adhesives or release-coating layer).
[0117] The packaging container of the invention comprising the laminates with a build-in open and reclose feature made as in the invention provides a tamper-evidence function because it is very difficult to replace the opening portions after initial opening exactly on the same place as before the opening. When the outer layer of the outer structure 8 is printed, in particular if it is reverse printed, it is almost impossible to achieve perfect registration of the printed matter across the score line when reclosing the package.
[0118] The packages as in the invention not only encompass flow packs or pouches (
EXAMPLES
Example 1
[0119] Example 1 corresponds to the embodiments shown in
[0120] Duplex Structure
[0121] A first structure of a white pigmented, oriented polypropylene film (WTD from Treofan Germany GmbH & Co. KG) is printed by means of solvent containing polyvinylbutyral colors (PVB from Siegwerk Druckfarben AG & Co. KGaA). A protection layer of polyamide (Release lacquer 10-609345-3 of Siegwerk Druckfarben AG & Co. KGaA) is then applied on the printed surface. A pressure-sensitive acrylic adhesive (Acronal DS 3556 from BASF) and the same release lacquer is then pattern applied on the virgin side (not printed side) of the polypropylene film.
[0122] In the same working step, a second structure of a metallized foamed polypropylene film (QCM from Treofan Germany GmbH & Co. KG) is covered on its entire surface with a solvent containing permanent polyurethane adhesive (Adcote 563 EA/Catalyst F from Dow Chemical Company). On the future positions of the release lacquer and the PSA pattern, the permanent adhesive layer is thinner than outside of these positions (imprints).
[0123] The first and the second structure are then adhesive laminated to create a duplex structure. On the backside of the metallized foamed polypropylene, a further cold seal (Naturlex Kautschuk EmulsionCold seal S 8085 von Sun Chemical) is pattern applied for the cross and longitudinal seal of the future pack (not represented)
[0124] Laser Perforation (ROFIN-BAASEL Lasertech Equipment)
[0125] The laser perforation of the duplex structure can performed according to numerous embodiments among which some are represented in
[0126] The chosen process essentially depends on the available aging conditions (availability of ovens) and on the available laser equipment.
[0127] Preferred embodiments are: [0128] aging for a few days before a laser cut is performed exline first on one side and then on the second side of the duplex structure; [0129] cut inline on both sides of the duplex laminate structure; [0130] separately cut inline the first and second structure before both structures are adhesive laminated to a duplex structure [0131] cut inline one of both structures before the adhesive lamination of both structures followed by the adhesive lamination step and then by the cut of the second structure.
[0132] After laser cut of the duplex structure to create the build-in opening and reclose feature for the reclosable packaging of the present invention, the duplex structure is cut into the right width and wound on rolls with the printed layer oriented outside.
Example 2
[0133] In Example 2, Example 1 was reproduced with the same adhesives and release lacquer but all applied on the first structure as shown in
Example 3
[0134] In Example 3, Example 1 was reproduced with the same adhesives and release lacquer all applied on the first structure after application of the permanent adhesive on the entire surface as shown in
[0135] All examples can additionally be equipped on the duplex structure with a cold seal on specific positions to seal the finished pack. The used cold seal is S 8085 of Sun Chemical. (This step is not represented in the figures.)
[0136] Physical Properties
[0137] The build-in opening and reclose feature shows first opening force values between 0.5 and 1.5N/15 mm according to ASTM F904:98R08 (former DIN 53357).