Film bag

Abstract

A film bag has a pair of longitudinally extending film face panels having longitudinal edges and first and second folded film gussets having longitudinal edges welded at longitudinal seams to respective longitudinal edges of the face panels and formed with two spaced throughgoing cuts forming a handle loop. A separate film inner liner panel lies against an inner face of the first gusset, extends a full transverse width of the first gusset, and is fixed at the longitudinal welds of the first gusset to the front panels so that the liner prevents leakage from the bag through the cuts.

Claims

1. A film bag comprising: a pair of longitudinally extending film face panels having longitudinal edges and transversely extending end edges; first and second folded film gussets having longitudinal edges and transversely extending end edges; longitudinal welds forming longitudinal seams between the longitudinal edges of the film gussets and the respective longitudinal edges of the face panels, the first gusset having between the respective longitudinal seams two spaced throughgoing cuts forming a handle loop; transverse welds forming transverse seams between the transverse end edges of the film gussets and the transverse end edges of the face panels; and a separate film inner liner panel longitudinally coextensive and transversely coextensive with and lying only against an inner face of the first gusset, extending a full transverse width between the longitudinal edges of the first gusset and a full longitudinal length between the transverse end edges of the first gusset, and fixed at the longitudinal and transverse welds of the first gusset to the face panels, whereby the liner prevents leakage from the bag through the cuts.

2. The film bag defined in claim 1, wherein the face panels and the second gusset are each formed by a single-layer plastic film.

3. The film bag defined in claim 1, wherein the first gusset is of the same plastic film as the face panels and second gusset.

4. The film bag defined in claim 1, wherein the cuts and the handle loop extend longitudinally.

5. The film bag defined in claim 4, wherein perforation lines extend longitudinally outward from ends of the cuts.

6. The film bag defined in claim 4, wherein the first gusset panel is formed by a plurality of film layers and the lining panel is formed of a polyolefin.

7. The film bag defined in claim 6, wherein the inner layer is polyethylene.

8. The film bag defined in claim 6, further comprising: a reinforcing layer between the inner layer and outer layer and connected to the handle loop.

9. The film bag defined in claim 1, further comprising: a transversely extending reclosable fastener in one of the face panels.

10. The film bag defined in claim 1, wherein the liner is between the first gusset and the face panels at the longitudinal and transverse seams.

11. The film bag defined in claim 1, wherein the film inner liner panel is fixed to the first gusset only at the respective longitudinal and transverse seams.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

(2) FIG. 1 is a perspective view of a side-gusset bag according to the invention;

(3) FIG. 2 is a vertical cross-section through the side-gusset bag according to the invention in the region of a handle loop;

(4) FIG. 2A is a large-scale view of the detail indicated at IIA in FIG. 2;

(5) FIG. 3 is a section like FIG. 2 for an alternative embodiment of the film bag;

(6) FIG. 3A is a large-scale view of the detail indicated at IIIA in FIG. 3;

(7) FIG. 4 is a schematic diagram showing the manufacture of the film bag;

(8) FIG. 5 is a large-scale diagram illustrating some of the steps for creating a strip comprising an outer film and an inner film; and

(9) FIG. 6 is a cross-section through the strip shown in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

(10) As seen in FIG. 1 a film bag comprises two face panels 1, a first side gusset 2, and a second side gusset 3 (FIG. 2 only). The side gussets 2 and 3 are between the two face panels 1 and are attached to the face panels 1 by longitudinal welds 4. The first side gusset 2 has a handle loop 6 formed by straight and parallel longitudinal cuts 5, and the hole formed by the handle loop 6 is covered on the inner side of the first gusset 2 by a separate inner lining film 7. Thus the handle loop 6 is actually an integral raised rectangular piece of the side gusset 2. At each longitudinal end, the panels 1 and gussets 2 and 3 are sealed together at a single transverse weld 18.

(11) FIG. 1 furthermore shows that the cuts 5 are extended at each end as longitudinally extending perforation lines 8 at the ends of the handle loop 6. These perforation lines 8 are intended to ensure there is no uncontrolled transverse tearing when an excessive load is placed on the handle loop 6.

(12) As indicated in the cross-section of FIG. 2, the inner film 7 extends transversely and longitudinally in the region of the handle loop 6 across the entire width and length of the first side gusset 2. The inner film 7 is accordingly attached to both the face panels 1 at the longitudinal and transverse welds 4 and 18. The first side gusset 2 is thus formed by an outer film 9 and the inner lining film 7, the cuts 5 only passing through the outer film 9 so that the inner lining film 7 ensures a tightly sealed closure at the handle loop 6, preventing leakage from the bag. Since the inner lining film 7 on the first side gusset 2 extends across the entire width and the entire length of this side gusset 2 a reliable seal is achieved without transitions or additional welds.

(13) FIG. 2 also shows that both front walls 1 and the outer film 9 of the second side gusset 3 are each made of only one film. A multilayer film is preferably used for the two face panels 1, the outer film 9 of the second side gusset 2 and all of the first side gusset 1 and has an inner weldable layer 10 on the inside of the film bag and an outer non-weldable layer 11 on the opposite side. The non-weldable layer 11 does not fuse, unlike the weldable layer 10, when the longitudinal and transverse welds 4 and 18 are made. The weldable layer can be made, in particular, of a polyolefin such as, for example, polyethylene (PE). A polyester such as polyethylene terephthalate (PET), or a biaxially oriented polypropylene (BO-PP) can be used for the non-weldable layer.

(14) FIG. 3 shows a variant of the film bag in which a reinforcement film 12 is provided between the inner lining film 7 and the outer film 9. The reinforcement film 12 is cut through together with the outer film 9 so as to form an inner layer on the loop 6 and increase the load-carrying capacity of the handle loop 6. Sealing accordingly continues to be effected by the inner lining film 7 that in this embodiment also extends across the entire length and width of the first side gusset 2.

(15) This film bag is made by a method wherein a web comprising multiple successive bag blanks is cut transversely to subdivide it longitudinally into the finished film bags. Such a method is disclosed in FIG. 4 of U.S. Pat. No. 7,775,957, which is herewith incorporated by reference.

(16) Initially, a first film web 13 from which one of the face panels 1 will subsequently be created is fed in a longitudinal feed direction P. A strip formed into a circular-section tube with the lengthwise edges of the strip upward and slightly spaced is fed transversely to and laid on the web 13, then cut off, leaving short tubular sections 14 of the strip lying atop the strip 14. FIG. 4 shows how the cut-off sections 14 of the strip are applied at a uniform longitudinal spacing and extending transversely to the direction P on the first film web 13. If the intent is to provide the film bags with a reclosable fastener 15, it is applied before a second film web 16 is laid on top of the first film web 13 and the strip sections 14.

(17) Subsequently, pairs of the longitudinal welds 4 are made perpendicular to the direction P on the diameter of each tubular section 14 so as to weld the strip sections 14 both to the second film web 16 at the folded-over edges and also to the first film web 13 on the opposite side.

(18) The webs 13 and 16 as well as the tube sections 14 are then cut through transversely of the direction P between each pair of the welds 4 so that individual film bags are separated from the webs 13 and 16 thus welded together sandwiching the strip sections 14. The cut is made at the centers of the strip sections 14, thereby creating the two side gussets 2 and 3 of successive film bags from respective halves of one folded strip section 14.

(19) According to the invention, the strip sections 14 are created from the above-described outer film 9 and inner lining film 7. As indicated in FIG. 5, the outer film 9 is fed and provided with the cuts 5 to create the handle loops 6. The inner lining film 7 is half as wide as the outer film 9 laminated to it so that only the first side gusset 2 is reinforced with the inner lining film 7 and the part of the section 14 forming the second side gusset 1.

(20) If the first gusset 2 of the embodiment of FIG. 3 is to be optionally provided with the reinforcement film 12, this film 12 is applied to the outer film 9 before the inner lining film 7 is fed in. In order to increase the carrying capacity of the handle loop 6, the inner lining film 7 and the outer film 9 can be attached to each other by longitudinal welds 17 (FIG. 5). The edges are then folded downward onto the strip section 14.

(21) FIG. 6 shows a cross-section through the strip section 14 thus created without the reinforcement film 12. If such strip sections 14 are used in the FIG. 4 process to make film bags, only one of the two side gussets 2 of the film bags has the handle loop 6.