FILM FOR EASY-OPEN PACKAGING

Abstract

Film strip (1) for wrapping food or pharma products, packaging made thereof and a process for manufacturing said packaging. The film strip (1) is made of a flexible and foldable composite film comprising a continuous protection layer (70) and on one outermost side of the composite film at least partly a sealing layer (11) which forms at least on one end part (12, 14) a sealing band (5, 6), wherein one sealing band (5) is further spaced apart from the corresponding end face (15) than the other one (6). The composite film comprises further at least one polymer layer (11, 70, 72) having at least one weakening line (40), wherein the weakening line/s start/s from the end face (15) whose sealing band (5) is further spaced apart from the corresponding end face (15) than the other sealing band (6), the weakening line/s extend/s further through said end part (14) and along the whole longitudinal extension B1 of the adjacent sealing band (5) or through the polymer film (11, 70, 72) lying above the whole longitudinal extension B1 of the sealing band (5) and further extend/s continuously into at least a part of said polymer layer (11, 70, 72) adjacent to said area of or above said sealing band (5) in the direction of the first end face (13).

Claims

1. Film strip (1) for wrapping food or pharma products, the film strip (1) has a width W between its two parallel longitudinal sides (3) and a length L between its two opposite lying end faces (13, 15) wherein adjacent to each end face (13, 15) the film strip (1) features an end part (12, 14), the film strip (1) is made of a flexible and foldable composite film comprising a continuous protection layer (70) and on one outermost side of the composite film at least partly a sealing layer (11) which forms at least on one end part (12, 14) of the film strip (1) a sealing band (5, 6) between the longitudinal sides (3) of the film strip (1), wherein each sealing band (5, 6) has a predefined length (B1, B2), wherein one sealing band (5) is further spaced apart from the corresponding end face (15) than the other one (6) if two sealing bands are provided and in case of only one sealing band, it is spaced apart from the corresponding end face (15), characterised in that the composite film comprises at least one polymer layer (11, 70, 72) having at least one weakening line (40), wherein the weakening line/s start/s from the end face (15) whose sealing band (5) is further spaced apart from the corresponding end face (15) than the other one (6), or in case where only one sealing band is provided, each weakening line (40) starts from the end face (15) of the end part (14) comprising said sealing band (5), extends further through said end part (14) and along the whole longitudinal extension B1 of the adjacent sealing band (5) or through the polymer film (70, 72) lying above the whole longitudinal extension B1 of the sealing band (5) and further extend/s continuously into at least a part of said polymer layer (11, 70, 72) adjacent to said area of or above said sealing band (5) in the direction of the first end face (13).

2. Film strip (1) according to claim 1, characterised in that each weakening line (40) is a straight line extending from the end face (15) whose adjacent sealing band (5) is further spaced apart from the corresponding end face (15) than the other sealing band (6) from the other end face (13), wherein the weakening line includes an acute angle to said end face (15).

3. Film strip (1) according to claim 1, characterised in that each weakening line (40) starts from the end face (15) whose adjacent sealing band (5) is further spaced apart from the corresponding end face (15) than the other sealing band (6) from the other end face (13), wherein the weakening line (40) extends perpendicularly to the end face (15) in an area between said end face (15) and said sealing band (5) and extends further in a continuous straight line arranged in an acute angle to said end face (15).

4. Film strip (1) according to claim 1, characterised in that the at least one polymer layer (11, 72) featuring the weakening line/s (40) is an oriented polymer film.

5. Film strip (1) according to claim 1, characterised in that the polymer film (11, 72) featuring the weakening line/s (40) is made of polyester, polyethylene 2,5-furandicarboxylate (PEF), polyethylene (PE), polypropylene (PP), polyamide (PA) or polymer-coated paper.

6. Film strip according to claim 1, characterised in that at least one sealing band (5, 6) has at least two sealing zones (20, 30) with different sealing performance, wherein one zone (30) providing a strong sealing strength and the other one is a weak zone (20) providing a low sealing strength.

7. Film strip according to claim 6, characterised in that the weak zone (20) is covered with a sealant varnish suitable for peeling.

8. Film strip according to claim 6, characterised in that the weak zone (20) of the sealing layer (11) is a cohesively breaking sealing layer.

9. Film strip according to claim 6, characterised in that the sealing band/s is/are made of a sealant varnish having different thicknesses in the zone (30) providing the strong sealing strength and in the weak zone/s (20).

10. Film strip according to claim 6, characterised in that the weakening line/s extend through at least one of the weak zones (20) of the sealing band (5).

11. Packaging made of a film strip (1) according to claim 1 for wrapping a food or pharma product, a first and a second end part (12, 14) of the film strip (1) are joined together by a sealing means in a junction or sealing area (25) defined by the sealing band/s (5, 6) with one of said end parts (14) overlying the other one (12) of said end parts (12, 14) defining the outer surface of said packaging, wherein the second end part (14) comprising the sealing band (5) that is further spaced apart from the corresponding end face (15) than the other one (6), or in case that only one sealing band (5) is provided, the second end part (14) comprising said sealing band (5) lies on top of the other first end part (12), wherein the area between the end face (15) of the second end part (14) and the adjacent sealing band (5) of the outer lying second end part (14) defines a junction-free zone providing a tear tab (50), wherein the sealing area (25) comprises a zone (30) providing a strong sealing strength and a weak zone (20) providing a lower sealing strength compared to that of the strong zone (30), characterised in that the weakening line/s of said polymer layer (11, 72) start/s from the end face (15) of the second end part (14), extend/s continuously through the junction-free zone and through the whole longitudinal extension of the weak zone (20) and further extend/s into at least a part of said polymer layer adjacent to said sealing zone (25) between the first and second end parts (12, 14).

12. Packaging according to claim 11, characterized in that the weakening line/s (40) extend along the whole border area of the weak zone at the junction zone between the weak (20) and the strong zone (30).

13. Packaging according to claim 11, characterized in that the outer lying second end part (14) is peelable from the subjacent end part (12) within the weak zone (20).

14. Packaging according to claim 11, characterized in that the packaging or wrapping (60) comprises a fin seal (26) showing an inside-inside seal, wherein the inner layer of the film strip (1) directed to the inside of the packaging (60) comprises at least partly the sealing layer (11) and in that the first end part (12) of said film strip (1) is folded back providing a sealing surface made of the sealing layer (11), the second end part (14) of the film strip (1) is sealed onto the folded back part (10) of the first end part (12), wherein the fin seal comprises at least one weak zone (20) having a low sealing strength, wherein the second end part (14) of the film strip (1) extends over the fin seal and the folded back part (10) of the first end part (12) to form the tear tab (50).

15. Packaging according to claim 11, characterized in that the packaging or wrapping (60) comprises a lap seal (27) showing an inside-outside seal, wherein the inner layer of the film strip (1) directed to the inside of the packaging (60) comprises at least partly the sealing layer (11), and in that the second end part (14) of the film strip (1) comprises said sealing layer (11) and is sealed onto the outside of the first end part (12) of the film strip (1), wherein the lap seal (27) comprises at least one weak zone (20) having a low sealing strength, wherein the second end part (14) of the film strip (1) extends over the lap seal (27) to form the tear tab (50).

16. Packaging according to claim 11, characterized in that the packaging (60) has a hermetically sealed inside.

17. A method for manufacturing a packaging according to claim 11 for wrapping a food or pharma product, characterized in that it includes the following steps: (a) providing a film strip (1) having two opposite end parts (12, 14) according to one of claims 1 to 10, (b) folding a second end part (14) of the film strip (1) over a first end part (12) of the film strip (1) in a manner that the distance between the outer end face (15) of the second end part (14) to the sealing area (25) is greater than the distance between the outer end face (13) of the first end part (12) to the sealing area (25), and at least a part of the sealing area (25) comprises a weak sealing zone (20) providing a sealing strength that allows the two sealed end parts (12, 14) to be peeled from one another, and that said sealing area (25) comprises the at least one weakening line (40), the weakening line (40) running continuously from the end face (15) of the second end part (14) of the film strip (1) through the whole longitudinal extension of the week zone (20) of the sealing area (25), and into at least a part of the film strip (1) adjacent to said sealing zone (25) in the direction of the first end part (12). (c) sealing the first and second end parts (12, 14) together wherein the free end face (15) of the second end part (14) of the film strip (1) extends over the sealing area (25) for providing a tear tab (50).

18. A method according to claim 17, wherein the sealing area (25) comprises a zone (30) providing a strong sealing strength and a weak zone (20) providing a lower sealing strength, characterized in that the different sealing strengths of the strong and weak sealing zones (20, 30) is created by the application of different sealing parameters, wherein the sealing zone (30) having the higher sealing strength is made by applying a higher sealing temperature and/or a higher sealing pressure and/or a longer sealing time compared to the sealing parameters used for the sealing zone (20) having weak sealing properties suitable for opening the packaging (60) by peeling the second (14) from the first end part (12) of the film strip (1).

19. A method according to claim 17, wherein the sealing surfaces of the first and/or second end parts (12, 14) are modified to have a different surface textures in the weak zone (20) and in the zone (30) providing a strong sealing strength.

Description

[0051] The invention will now be described by way of examples and with reference to the accompanying drawings in which:

[0052] FIG. 1 shows schematically a top view onto an inventive film strip;

[0053] FIG. 2 shows schematically a cross section through a composite film of the inventive film strip;

[0054] FIG. 3 shows schematically a topview onto the junction or sealing zone of an inventive packaging;

[0055] FIG. 4 shows schematically a topview onto an opened packaging having a fin seal between the sealed opposite end parts of a film strip;

[0056] FIG. 5 shows a cross-section through the packaging shown in FIG. 4;

[0057] FIG. 6 is a perspective view of the packaging shown in FIGS. 4 and 5 in a closed state enclosing a packaged product;

[0058] FIG. 7 is a perspective view of the packaging shown in FIGS. 4 and 5 in an open state;

[0059] FIG. 8 shows schematically a topview of a packaging having a fin seal between the sealed opposed end parts of a film strip having two parallel weakening lines surrounding the packaging to the full extent.

[0060] FIG. 9 is a perspective view of the packaging shown in FIG. 8 in a closed state enclosing a packaged product;

[0061] FIG. 10 is a perspective view of the packaging shown in FIG. 8 in a partially open state;

[0062] FIG. 11 shows schematically a topview onto a closed packaging having a lap seal between the sealed opposed end parts of an inventive film strip;

[0063] FIG. 12 shows a cross-section through the packaging shown in FIG. 11.

[0064] FIG. 1 shows a top view onto a film strip 1 having a width W between its two parallel longitudinal sides 3 and a length L between its two opposite lying end faces 13, 15, wherein adjacent to each end face 13, 15 the film strip 1 features an end part 12, 14. Each end part 12, 14 of the film strip 1 has a sealing band 5, 6 between the longitudinal sides 3 of the film strip 1, wherein the sealing layer 11 in FIG. 1 is only present in said sealing bands 5, 6. Each sealing band 5, 6 has a predefined length B1, B2, wherein the sealing band 5 is further spaced apart from the corresponding end face 15 than the other one 6. The film strip 1 shown in FIG. 1 has at least two transparent polymer layers on top of the sealing bands 5, 6, thus allowing to see the polymer layer having two weakening lines 40A, 40B. The polymer layer having the weakening lines 40A, 40B may be the outermost layer lying opposite to the sealing layer 11, wherein the continuous protection layer is an intermediate layer. On the other hand, the polymer layer having the weakening lines may be an intermediate layer and the continuous protection layer may be the outermost layer lying opposite to the sealing layer.

[0065] One weakening line 40A runs in a straight line at an acute angle to the end face 15 starting from the outer edge or end face 15 of the end part 14, extends through the end part 14 including the longitudinal extension B1 of the sealing band 5 and further extends into a part of said polymer layer of the film strip 1 in the direction of the second sealing band 6. A second weakening line 40B first runs perpendicular to the end face 15 in an area between the end face 15 and the sealing band 5 and then runs above the longitudinal extension of the sealing band 5 and further into the polymer film of the film strip 1 lying between the two opposite sealing bands 5, 6 in a straight line having an acute angle with said end face 15.

[0066] FIG. 2 shows schematically a cross section of a preferred composite film used for the inventive film strip 1. The composite film has a sealing layer 11 and an outer protection layer 70 as well as an intermediate polymer layer comprising the weakening line/s. Alternatively, layer 70 may comprise the weakening line/s and layer 72 may be the continuous protection layer. As a further alternative, the sealing layer may be a continuous protection layer and the outermost layer and/or the intermediate layer may comprise the weakening line/s.

[0067] FIG. 3 shows a topview onto a junction or sealing zone 25 of a flexible film strip 1 having a sealing zone 20, called weak zone 20, providing a weak sealing strength and a sealing zone 30 providing a strong sealing strength. The film strip 1 has two opposite lying end parts 12, 14 and shows two parallel weakening lines 40 starting from the outer edge 15 of the second end part 14, passing the weak zone 20 and continue in the direction of the first end part 12 of the film strip 1.

[0068] FIG. 4 shows a topview onto an opened packaging 60 made of a flexible film strip 1 having two opposite lying end parts 12, 14. The sealing layer 11 comprises a sealing area 25 having two zones 20, 30 with different sealing performance wherein the zone 30 provides a strong sealing strength and the other one is a weak zone 20 providing a low sealing strength. The package 60 presented in FIG. 4 has a fin seal 26 showing an inside-inside seal, wherein the inner layer of the flexible film strip 1 directed to the inside of the packaging 60 comprises a sealing layer 11. The first end part 12 of said film strip 1 is folded back providing a fold edge 9 and a folded back part 10 that serves as sealing surface made of the sealing layer 11. The first and second end parts 12, 14 of the film strip 1 form an overlapping zone comprising a sealing area 25, 26. The second end part 14 of the film strip 1 is sealed onto the folded back part 10 of the first end part 12. The second end part 14 of the film strip 1 extends over the sealing area 25 and the folded back part 10 of the first end part 12, i.e. the outer edge 15 of the second end part 14 of the film strip 1 overlaps the outer edge 13 of the first end part 12 and the sealing area 25, 26 to form a tear tab 50. The packaging shown in FIG. 4 features a single weakening line 40 wherein said weakening line 40 is in the form of a straight line enclosing an acute angle with the outer edge 15 of the second end part 14 of the film strip 1. The weakening line 40 extends from the outer edge 15 of the second end part 14 through the weak zone 20 of the sealing area 25, 26 into the flexible film strip 1 adjacent to the weak zone 20, i.e. into the part of the film strip 1 adjacent to the weak zone 20 lying opposite to the second end face 15. Consequently, the second end part 14 teared back along the weakening line 40 has the form of a triangle and uncovers an access zone 45 for a packaged product.

[0069] FIG. 5 shows a cross-section through the packaging presented in FIG. 4. The packaging 60 comprises a fin seal 26 and the first end part 12 is folded back. The outer edge 15 of the second end part 14 (upper end) extends over the outer edge 13 of the folded back portion 10 of the first end part 12 and provides a tear tab 50. The part of the second end part 14 overlapping the folded back part 10 of the first end part 12 defines the sealing area 25, 26. FIG. 5 shows clearly that the distance between the outer lying edge 15 of the second end part 14 to the sealing area 25 is greater than the distance between the inner lying outer edge 13 of the first end part 12 to the sealing area 25, 26.

[0070] FIG. 6 is a perspective view of the packaging shown in FIGS. 4 and 5 in a closed state enclosing a packaged product. The weakening line 40 starts at the outer edge 15 of the second end part 14 (upper end of the film strip 1) and runs further in the polymer layer having the weakening line 40 to the end of the upper surface of the packaging 60. The sealing area 25 features on the left of the weakening line a zone 30 having a strong sealing strength. On the right side of the weakening line 40 the sealing area 25 consists of a zone 20 having a weak sealing strength.

[0071] FIG. 7 is a perspective view of the packaging shown in FIGS. 4 and 5 in an open state, i.e. after tearing off the second end part 14 of the film strip 1 along the weakening line 40. The teared off part of the second end part 14 reveals the outer edge 13 of the first end part 12 of the film strip 1. FIG. 7 also shows the large extension of the second end part 14 from the outer edge 13 of the first end part 12 thus creating a large tear tab 50.

[0072] FIG. 8 shows a topview onto a packaging 60 made of a flexible film strip 1 having two opposite lying end parts 12, 14. The sealing layer 11 comprises a sealing area 25 having two zones 20, 30 with different sealing performance wherein the zone 30 provides a strong sealing strength and weak zone 20 provides a low sealing strength. The package shown in FIG. 8 has a fin seal 26 showing an inside-inside seal, wherein the inner layer of the flexible film strip 1 directed to the inside of the packaging 60 comprises a sealing layer 11. The first end part 12 of said film strip 1 is folded back providing a fold edge 9 and a folded back part 10 that serves as sealing surface made of the sealing layer 11. The second end part 14 of the film strip 1 extends over the sealed folded back part 10 of the first end part 12 forming a free lying end of the second end part 14 forming a tear tab 50. The packaging of FIG. 8 features two parallel weakening lines 40 surrounding the whole cross-section of the packaging, wherein the weakening lines 40 enclose an acute angle with the outer edge 15 of the second end part 14 of the film strip 1. The two weakening lines 40 enclose a tear strip 42. The weakening lines 40 extends from the outer edge 15 of the second end part 14 through the weak zone 20 of the sealing area 25, 26 and end in the first end part 12 of the film strip 1. The outer edge 15 of the second end part 14 features at the start of each weakening line 40 a notch 55 as opening aid. The packaging shown in FIG. 8 allows a full transverse side as access zone 45 for a packaged product, e.g. a chocolate bar wrapped by said film strip 1 in a direction parallel to the outer edges 13, 15 of the end parts 12, 14.

[0073] FIG. 9 is a perspective view of the packaging 60 shown in FIG. 8 in a closed state enclosing a packaged product. The weakening lines 40 start at the outer edge 15 of the second end part 14 (upper end of the film strip 1) and surround the whole cross-section of the packaging.

[0074] FIG. 10 is a perspective view of the packaging shown in FIG. 8 in a partially open state, i.e. after tearing off partly the strip 42 between the two weakening lines 40. The teared off strip 42 of the second end part 14 reveals the outer edge 13 of the first end part 12 of the film strip 1. FIG. 8 also shows the large extension of the second end part 14 from the outer edge 13 of the first end part 12 thus creating a large tear tab 50.

[0075] FIG. 11 shows schematically a topview onto a closed packaging 60 having a lap seal 27 between the two opposite lying end parts 12, 14 of a film strip 1. The sealing is performed between the inner sealing layer of the second end part 14 and the outer surface of the first end part 12, wherein the second end part 14 of the film strip 1 overlaps the outer surface of the first end part 12 of the film strip 1. The sealing area 25, 27 between the two opposite lying end parts 12, 14 has two zones 20, 30 with different sealing performance wherein the one zone 30 provides a strong sealing strength and the other one is a weak zone 20 providing a low sealing strength. The second end part 14 of the film strip 1 extends over the sealing area 25, 27, i.e. the outer edge 15 of the second end part 14 of the film strip 1 overlaps the outer edge 13 of the first end part 12 and the sealing area 25, 27 to form a tear tab 50. The packaging shown in FIG. 11 features a single weakening line 40 surrounding the whole cross-section of the packaging 60. The weakening line 40 extends from a notch 55 as opening aid at the outer edge 15 of the second end part 14 and runs through the weak zone 20 of the sealing area 25 and surrounds the whole cross-section of the packaging 60 to end in the first end part 12 of the film strip 1. Consequently, the packaging 60 shown in FIG. 11 allows a full transverse side as access zone 45 for a packaged product, e.g. a chocolate bar wrapped by said film strip 1 in a direction parallel to the outer edges 13, 15 of the end parts 12, 14.

[0076] FIG. 12 shows a cross-section trough the packaging shown in FIG. 11. The package comprises a lap seal 27. The outer edge 15 of the second end part 14 (upper end) extends over the outer edge 13 of the first end part 12 and the sealing area (25, 27) and provides a tear tab 50.

[0077] The sealing strength of a number of different layer structures of the composite film has been measured. The test results are presented in Table 1. The composite structure shown in table 1 indicate the layer structure from outside to the inside, i.e. to the sealing layer. Furthermore, the thickness of the corresponding layer has been indicated after the material. The corresponding composite films have been folded and the two end parts of the composite film have been sealed together. Fin and lap seals have been tested. The sealing bar had a predefined temperature and has been pressed onto the sealing area of the composite film with a predefined pressure for a predefined duration (sealing time). The tests have been performed by heating only one side of the sealing means, i.e. the sealing bar, if in table 1 the heated sides is indicated with 1. If in table 1 the heated sides is indicated with 2, the counterpart of the sealing bar has been heated too. Tests have been performed with a sealing bar having a flat sealing surface as well as with a sealing bar having a corrugated sealing surface. The sealing strength has been measured by measuring the peel strength.

[0078] Only test no. 11 has been done using a lap seal showing an inside-outside seal. Test numbers 1 to 10 and 12 to 16 concern a fin seal showing an inside-inside seal.

TABLE-US-00001 TABLE 1 Sealing Sealing sealing heated sealing bar Seal/peel Test composite structure: temperature pressure time sides profile strength subject of the Test no. [ ] [ C.] [N/cm2] [sec] [ ] [ ] [N/15 mm] [ ] 1 Alu9/PET12/sealing varnish 1 (3.2 g/m2) 120 50 0.5 1 flat 1.21 weak seal 2 Alu9/PET12/sealing varnish 1 (3.2 g/m2) 150 50 0.5 2 flat 0.92 weak seal 3 OPP30/PE30/sealing varnish 2 (2.0 g/m2) 120 50 0.5 1 flat 2.70 weak seal 4 PET12/PE40 selaing varnish 3 (1.8 g/m2) 120 50 0.5 1 flat 4.17 weak seal 5 PET12/PE40 120 50 0.5 1 flat 36.03 strong seal 6 PET12/HDPE50 peelable 150 50 0.5 2 flat 6.19 weak seal 7 PET12/HDPE50 peelable 150 50 0.5 2 corrugated 9.65 strong seal 8 PET12/HDPE50 peelable 150 50 1 2 corrugated 9.25 strong seal 9 PET12/HDPE50 peelable 190 50 1 2 corrugated 19.97 strong seal 10 OPP30/Met.OPP35/sealing varnish 2 (2.0 g/m2) 150 50 0.5 2 flat 3.70 weak seal 11 OPP30/Met.OPP35/sealing varnish 2 (2.0 g/m2) 120 50 0.5 2 flat 1.73 weak seal 12 OPP30/Met.OPP35 150 50 0.5 2 flat 5.11 strong seal 13 Alu7/sealable PET23 150 50 0.5 2 flat 13.27 strong seal 14 Alu7/sealable PET23/sealing varnish 2 (2.8 g/m2) 150 50 0.5 2 flat 2.84 weak seal 15 Alu7/sealable PET23/sealing varnish 2 (2.8 g/m2) 120 50 0.5 1 flat 3.01 weak seal 16 Alu7/sealable PET23/sealing varnish 1 (3.2 g/m2) 120 50 0.5 1 flat 2.46 weak seal