Bag with Zipper Closure and Side Folds and Method for Making such a Bag

Abstract

There is disclosed a bag (101) with a zipper closure and a method for making such a bag. The bag is formed of a first (102) and a second (103) superposed flat side and folded side pieces (104) disposed between the flat sides of the bag and welded to edge areas at the side edges of the flat sides. The bag includes interacting zipper parts (114) in the form of a male part (120) and a female part (119) connected with each their flat side and extending from side edge to side edge. In order to achieve the largest possible opening of the bag, the folded side edges are extending from the bottom edge of the bag to the top edge of the bag. In the side pieces a thinning of material (123) is established in an area next to the areas in the flat sides where the zipper parts are disposed. Thus, the side pieces in the thinned area will have a material thickness enabling the male and female parts to engage each other while at the same time the material of the side pieces is clamped there between.

Claims

1. A bag (101) with a zipper closure, wherein the bag is formed of: a first (102) and a second (103) superposed flat side formed of a first plastic film and folded side pieces (104) formed of a second plastic film and which are disposed between the flat sides (102,103) of the bag and welded to edge areas (106) at the side edges of the flat sides (102,103), the bag including interacting zipper parts (116,117) in the form of a male part (117) and a female part (116) connected with each their flat side (102,103) and extending from side edge (107) to side edge (107) of the bag (101), wherein the folded side pieces (104) extend from the bottom edge of the bag to the top edge of the bag, and wherein in the side pieces (104) a thinning (115) of material is established in an area opposite to the zipper parts disposed on the flat sides (102,103), such that the side pieces (104) in the thinned area have a material thickness enabling the male and female parts (117,116) to engage each other while at the same time the material of the side pieces is clamped there between, and wherein the second plastic film (121) comprising the thinning (115) is made of a multi-layered film where the film layers form a reduced material thickness (123) at the thinning (115).

2. A bag according to claim 1, wherein the zipper parts are strip-shaped, and wherein the male part has a projection, and that the female part is made of two resilient legs forming a concavity adapted to receive the projection of the male part and the folded side pieces when the projection of the male part is pressed in between the legs of the female part.

3. A bag according to claim 1, wherein the side pieces in the area opposite the thinned parts have a thickness between 5 and 25 m, preferably between 10 and 20 m.

4. A bag according to claim 1, wherein the flat sides and the side pieces are formed of a plastic film with a thickness between 50 and 200 m, preferably between 80 and 120 m.

5. A bag according to claim 1, wherein the superposed first and second flat side are made of multi-layered films, that at least the outermost layers of the first and second flat sides facing each other are made of a weldable plastic material, and wherein at least the outermost layers of the side pieces facing the flat sides are made of a weldable plastic material.

6. A bag according to claim 5, wherein at least the outermost layers of the first and the second flat sides facing away from each other are made of a non-weldable plastic material.

7. A bag according to claim 5, wherein the weldable material is PE or PP, and that the non-weldable plastic material is PET, OPA or OPP.

8. A bag according to claim 1, wherein the zipper parts are welded or glued to the flat sides.

9. A bag according to claim 1, wherein the thinning is formed by forming the side pieces of the bag of an extruded web with the thinning produced by extrusion.

10. A bag according to claim 1, wherein the bag is also provided with a folded bottom.

11. A method for making a bag (101) with a zipper closure, the bag being formed of a first and a second flat side (102,103) that are mutually superposed, and side pieces (104) that are inserted and folded between the flat sides (102,103) of the bag and welded to edge areas (106) at the side edges of the flat sides, the bag including interacting zipper parts (116,117) in the form of a male part (117) and a female part (116) connected with each their flat side and extending from side edge (107) to side edge (107) of the bag (101), wherein the method comprises steps of providing the first and the second flat side (102,103), superposing the flat sides and providing zipper parts (116,117) and placing these on the flat sides (102,103), and disposing folded side pieces (104) between the flat sides extending from the bottom edge of the bag to the top edge of the bag, that in the side pieces, prior to placing the zipper parts (116,117), a thinning (115) of material is established in an area opposite to the zipper parts provided on the flat sides such that the side pieces in the thinned area are imparted a material thickness that enables the male and female parts to engage each other while at the same time the material of the side pieces (104) is clamped there between, and wherein the second plastic film (121) comprising the thinning (115) is made of a multi-layered film where the film layers form a reduced material thickness (123) at the thinning (115).

12. A method according to claim 11, wherein the superposed flat sides are made of multi-layered films, that at least the outermost layers of the first and second flat sides facing each other are made of a weldable plastic material, and that at least the outermost layers of the side pieces facing the flat sides are made of a weldable plastic material.

13. A method according to claim 11, wherein at least the outermost layers of the first and the second flat sides facing away from each other are made of a non-weldable plastic material.

14. A method according to claim 12, wherein the weldable material is PE or PP, and that the non-weldable plastic material is PET, OPA or OPP.

15. A method according to claim 11, wherein the bags are made in continuous webs where the zipper parts are applied in long strip-like webs, and that the webs are cut so as to form individual bag items wherein the zipper parts extend between the side edges of the bags.

Description

DESCRIPTION OF THE DRAWING

[0044] The invention will now be explained in more detail with reference to the accompanying schematic drawing, wherein

[0045] FIGS. 1 and 2 show a plan view and a top view, respectively of a prior art bag;

[0046] FIGS. 3 and 4 show views corresponding to FIGS. 1 and 2 of a bag according to the invention;

[0047] FIGS. 5A and 5B show sectional views on the line V-V in FIG. 3 with the bag in open and closed condition, respectively;

[0048] FIG. 6 shows a schematic view of a film web for use in making the side pieces;

[0049] FIG. 7 shows an item cut from the film web shown in FIG. 6 for use in formation of the side pieces;

[0050] FIG. 8 shows a presentation in principle where the items shown in FIG. 7 are disposed between the two film webs for forming flat sides and side faces of the bag item; and

[0051] FIG. 9 shows a schematic view corresponding to FIG. 6 of an alternative film web for use in making the side pieces.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0052] In the description, identical or corresponding elements will be provided with the same designations, however such that the embodiment associated with the invention will have designations of the prior art embodiment but added 100. A prior art bag 1 shown in FIGS. 1 and 2 will therefore be designated as the bag 101 in FIGS. 3 and 4 that show a bag according to the invention.

[0053] In FIGS. 1 and 2 is seen a bag 1 according to prior art. The bag 1 is formed of a first flat side 2 and a second flat side 3. Folded side pieces 4 are disposed between the two flat sides. Broken lines 5 in FIG. 1 illustrate a folding that at the same time indicates the extension of the folded side pieces 4. The side pieces 4 are welded to the flat sides 2, 3 in edge areas 6 adjacent to the side edges 7 of the flat sides. At the bottom, the bag is provided with a folded bottom piece 8, and the extension of the latter is shown by the broken line 9 indicating the folding of the folded bottom piece 8. The bottom piece 8 is welded also to the flat sides at an edge area 10 adjacent to the lower side edge 11 of the bag.

[0054] At the upper side edge 12 of the bag is provided an opening 13 (see FIG. 2).

[0055] The bag 1 is provided with a zipper 14 running in parallel with the upper side edge 12 of the bag surrounding the opening 13. The zipper 14 runs between two opposing side edges 7 of the bag.

[0056] The zipper is formed of strip-shaped zipper parts 116 and 117, which will be explained in more detail with reference to FIGS. 5A and 5B.

[0057] In FIG. 1 is seen that the side folds 4 have an upper oblique edge 5 located at a position under the zipper 14. A film strip 16 covers the upper end of the side pieces 4, gluing the latter to one of the flat sides 2, 3 of the bag in order to ensure a tight closure of the bag.

[0058] In FIG. 2, the bag 1 shown in FIG. 1 is seen from above when opened. Therefore it appears that the opening 13 is lenticular, extending between the two direct weldings of the flat sides 2, 3 in the edge areas 6.

[0059] Irrespectively that the bag 1 at a position under the zipper 14 is provided with folded side pieces 4, which enables increased volume and a larger cross-section of the bag, the bag will have the shape appearing on FIG. 2 in the opening 13.

[0060] A bag 101 according to the invention is shown in FIGS. 3 and 4. This bag differs primarily in that the folded side pieces 104 extend over the entire height of the bag, up to the top edge 112 surrounding the opening 113 of the bag. Moreover, the side pieces 104 are modified by formation of a thinning 115, as explained below. Broken lines 105 in FIG. 3 illustrate a folding which at the same time indicates the extension of the folded side pieces 104.

[0061] Particularly clearly appearing on FIG. 4, the folded side pieces 104 are welded at the edge areas 106. When opening the bag, the folded side pieces 104 will be unfolded as illustrated in FIG. 4. The opening 113 of the bag hereby appears with a largely rectangular cross-section. The opening 113 will therefore be substantially larger than the opening 13 shown in FIG. 2.

[0062] A thinning 115 is formed in the side pieces 104 at the location of the zipper 114. This thinning 115 appears more clearly on FIGS. 5-8.

[0063] FIGS. 5A and 5B show the situation of the zipper 114 in open and closed condition, respectively.

[0064] The zipper 114 consists of the zipper parts 116 and 117. The zipper element 116 is a female part. A cross-section of a strip-shaped element is shown. The female part has to resilient legs 118 surrounding a concavity 119. The male part 117 is also strip-shaped, having a strip-shaped projection 120 intended for reception in the concavity 119.

[0065] As illustrated in FIGS. 5A and 5B, the folded side pieces 104 in the area at the zipper are superposed each other such that there are two folded parts of a side piece opposite the zipper 114. The thinning 115 is located opposite the two zipper parts 116 and 117.

[0066] When the zipper parts 116 and 117 are brought to engage as illustrated in FIG. 5B, the two thin material layers from the side pieces 104 will be clamped within the concavity 119 and secured by the engagement of the projection 120. Due to the resiliency of the legs 118, the additional material thickness located opposite the side pieces can be accommodated in the zipper.

[0067] FIG. 6 illustrates a film web 121 in which a thinning 115 is formed. The arrow 122 indicates the direction of producing the web. The web is made by extrusion in a flat nozzle such that the thinning 115 appears in the film web 121 during the making thereof. It appears here that the material thickness 123 at the thinning is significantly smaller than the material thickness 124 of the film web 121. The thinning 115 appears as a recess with a material thickness 124 at each side of the thinning 115. The web can alternatively be made as a multi-layered film where the film layers form a reduced material thickness 123 at the thinning.

[0068] The material thickness opposite the thinning will typically be between 5 and 25 m, preferably between 10 and 20 m. The material thickness of the plastic film will typically be between 50 and 200 m, preferably between 80 and 120 m.

[0069] FIG. 7 shows an item 125 cut from the material web 121 and then folded for forming a tubular shape with the thinning 115 disposed externally of the tubular shape.

[0070] FIG. 8 illustrates how the tubular items 125 are disposed between a first film web 126 and a second film web 127 that are used for forming the first and the second bag sides 102 and 103, respectively.

[0071] The items 125 will thus be squeezed flat when the film webs 126 and 127 are joined. Then, cutting at cutting lines marked by the broken lines 128 is performed. An item will thus constitute a side piece formed in a bag which is made by a method described in principle in U.S. Pat. No. 6,796,932.

[0072] In FIG. 8 appears one zipper element 117 fastened to the film web 127 at a position before the items 125 are applied. The zipper element 116 will be placed at the bottom side of the film web 126.

[0073] When the items 125 are placed between the two film webs, the two outwardly facing thinnings 115 will therefore be disposed opposite the position of the zipper parts 116, 117.

[0074] Alternatively, it is possible to have thinnings 115 at the opposite side of the film webs.

[0075] The making of the bags takes place by moving the film webs in the direction indicated by the arrow 129.

[0076] It is noted that FIG. 8 only illustrates part of the production process as reference incidentally is made to the description of the principle of a production process given in U.S. Pat. No. 6,796,932.

[0077] FIG. 9 illustrates an alternative film web 121 in which a thinning 115 is formed. The arrow 122 indicates the direction of producing the web. The web is made by extrusion in a flat nozzle such that the thinning 115 appears in the film web 121 during the making thereof. It appears here that the material thickness 123 at the thinning is significantly smaller than the material thickness 124 of the film web 121. The thinning 115 appears as an edge area with a material thickness 124 only at one side of the thinning 115. The web can alternatively be made as a multi-layered film where the film layers form a reduced material thickness 123 at the thinning.