Field of the Invention

The present invention flexible polymer bags that are commonly in use as bin liners, carrier bags, or in similar applications.

Background to the Invention

Bin liners and similar flexible polymer bags are well known. In the context of the present invention a flexible polymer bag will be understood to consist of a flexible polymer bag that is open at an upper end and sealed at a lower end. They may or may not have handles or a drawstring to facilitate closing of the bag after use. They are generally formed of a relatively thin and flexible polymer. The specific polymer and thickness of the polymer are generally selected based on the specific intended use of the bag. For example, thicker bags may be provided for larger bins or for use with waste that is more likely to tear a bag, such as garden waste.

Often, flexible polymer bags are formed as a continuous roll of bags. A weld line across the width of the bag is provided to seal the lower end of the bag and a cut line or perforation line is provided adjacent the weld line to form the top of the adjacent bag. A single bag may be removed from the roll by tearing along the perforation line.

One method of forming flexible polymer bags is as follows. A polyethylene ring is blown into a bubble that is then collapsed into a flat tube. Rollers then pull the flat tube. The flat tube is then welded across its width to seal each bag at a lower end and perforation lines are provided adjacent the weld. This is only one method of forming flexible polymer bags and is provided as an example only. Flexible polymer bags may also be formed individually and/or from alternative materials. The person skilled in the art will be aware of various different methods of forming flexible polymer bags and all such methods may be used in the present invention unless the claims indicate otherwise. Generally, in use, bin bags are positioned within a bin and the upper end of the bag is folded over the upper end of the bin and a bin lid is then placed on top of the bin to hold the bag in position whilst the bin is in use. As set out above, the bin bag may have handles to allow the full bag to be lifted and tied. However, all such bags can be difficult to remove from the bin, may not hold in position in the bin effectively. Draw strings do overcome these issues to a certain extent but the additional cost of forming draw strings can be significant due to the additional materials and processing steps required.

In light of the above, there is a need for improved bin bags that are simple to manufacture and that overcome the shortcomings of existing bin bags.

Summary of the Invention

The present invention provides a flexible polymer bag that is open at a first end and welded closed at a second end, wherein two pointed ears are provided at opposing lateral sides of the first end of the bag, characterized in that: each of the pointed ears is formed of at least two layers and comprises a weld feature that welds all of the layers of the ear together; and the pointed ears are wider at a proximal end than at a distal end.

As will be readily understood, the first end of the bag will generally be the upper end of the bag when it is in use. For example, when used as a liner for a bin the first end will be located at the upper end of the bin and the second end will be located at the lower end of the bin.

The pointed ears of a bag according to the present invention may be long enough to allow a user to tie the ears in a knot, preferably a double-knot, and thereby secure the contents of the bag. The present invention is advantageous in that the welding of the ears provides extra strength and allows lifting of the bag to be carried out more easily, particularly when the bag is full and single ply ears might tear. Further, the welding of the ears offers a restriction of the opening at the first end of the bag to provide better grip when used in a bin. In particular, a bag according to the present invention may grip the upper end of a bin better than a bag according to the prior art. The upper end of a bag according to the present invention is excellent at gripping bins of all shapes, including cylindrical bins, bins with square or rectangular upper ends, and/or bins that narrow towards their base.

Whilst the bag of the present invention is excellent for use as a bin bag, bags according to the present invention may be used for any purpose for which polymer bags are suitable. This includes but is not limited to freezer bags, carrier bags, and sandwich bags. A bag according to the present invention may of any suitable size for its intended use.

A bag according to the present invention may be made of suitable polymer that can be formed into a flexible bag and welded. Suitable polymers include but are not limited to polyethylene, biodegradable polymers, or any other equivalent material. Generally, a bag according to the present material will be made of a single homogeneous polymeric material as this is the most cost-effective and simple way to manufacture the bag. However, in embodiments of the invention two or more different polymers may be used for different parts or layers of the bag. Advantageously in embodiments of the invention one or more of the polymers used to manufacture a bag according to the present invention may be partly or wholly recycled.

A bag according to the present invention may be formed in the same manner as bags according to the prior art with walls formed of a single layer of polymer. In such embodiments the ears will be formed of two layers of polymer, each formed from an opposing wall of the bag. Alternatively, bags according to the present invention may by multi-layer and have walls formed of two, three, or more layers of polymer. In such embodiments the ears will generally be formed of each of the layers of the polymer. The exception to this is embodiments in which additional layers do not extend to the ears. For example, if an additional layer is provided away from the ears to reinforce a portion of the bag away from the ears then the ears may comprise fewer layers than the bag. In all embodiments of the invention the ears will be welded completely through each layer of each ear. That is, the weld feature will extend through each layer of an ear.

The weld feature of the invention may be a heat weld formed by melting the layers of the polymer together. This may be done in any manner apparent to the person skilled in the art, for example IR welding, ultrasonic welding, hot gas welding, or heat press welding. Any method that acts to weld the layers of polymer together may be utilized.

The weld feature of the invention may extend completely across a width of the ear or may extend only partially across the ear. The weld feature may consist of a welded line, a welded area, one or more spot welds, a weld surrounding an aperture, or any other weld feature that acts to weld the layers of the bag together. In embodiments of the invention the weld feature is a triangular weld patch. Such a triangular weld patch may cover substantially all of the distal portion of an ear.

In embodiments of the invention one or both ears may comprise a weld feature that extends completely across a width of the ear. Alternatively or additionally, one or both ears may comprise one or more weld feature that are a spot weld. That is, one or more spot welds may be provided on one or both ears. Alternatively or additionally, one or both ears may have a weld feature wherein substantially the whole of a distal portion of each ear is welded.

In embodiments of the invention the weld feature may be provided in an distal portion of the ear only, such that a proximal portion of the ears remains unwelded and the layers of the proximal portion are separate. In such embodiments a proximal portion of an ear may consist of 10% 20%, 30%, 40%, 50%, 60%, 70%, or 80% of the height of the ear. In embodiments of the invention substantially the entirety of the upper portion of an ear may be welded.

The first end of a bag according to the present invention may be curved between the two ears. For example, the first end of the bag may have a shape that consists of a single curve that extends from the proximal end of each ear to a lower point part-way between the ears. This may be a parabolic curve or any other suitable curve. This shape has been found to be particularly advantageous as it allows simple tying of the ears together. A curved shape also facilitates usage of the bag in a bin or in other similar uses. As an alternative to a curve, the first end of the bag between the two ears may have any other shape that extends to a lower point part-way between the ears, for example a V-shape or a shape comprising one or more linear and/or curved sections.

A bag according to the present invention may have a rounded second end. Having a rounded second end is advantageous in that it avoids wasted areas of material at the second end when the bag is in use: the rounded second end conforming better to receptacles in which the bag may be used. In embodiments of the present invention the rounded shape of the second end of the bag may conform to a curved shape of the first end of the bag. This can be advantageous as it allows the easier manufacture of the bags: the second end of one bag may be formed immediately adjacent to the first end of an adjacent bag on a production line and/or the bags can nest into one another. For example, if the bags are formed in a contiguous in the manner of the prior art the weld of the second end of a bag may be formed immediately adjacent a cut line that forms the first end of the bag. Forming bags in this manner minimises waste material as none of the material is thrown away.

A cut line forming the first end of the bag may be extend completely across the with of a bag and completely through all layers of the bag. Alternatively, a perforation line may be provided that keeps the first end of a bag connected to the second end of an immediately adjacent bag and allows a user to easily separate the bags by tearing along the perforation line. As will be readily understood, in such embodiments the shape of the first end of a bag may conform to the shape of the second end of an immediately adjacent bag.

In order to facilitate tying or carrying of the bag one or more punch holes may be provided through one or both pointed ears. If a punch hole is provided in an ear, part or all of the circumference of the punch hole may consist of a weld feature. A bag according to the present invention may further comprise an internal gusset for reinforcing the bag when in use.

The present invention also provides a contiguous line of two or more flexible bags according to any preceding claim, wherein a first end of each flexible bag is formed immediately adjacent to, and has a corresponding shape to, a second end of an adjacent flexible bag. Such a contiguous line may be formed in the same manner as bags according to the prior art, as described above in the background section of the application, or in any other manner apparent to the person skilled in the art.

As discussed above, in a contiguous line of flexible bags the shape of a first end of each flexible bag may also define the shape of the second end of an immediately adjacent bag. The shapes of the bags may be designed on that basis. For example, the first end of each flexible bag may have a parabolic shape or a U-shape or any other suitable shape that defines both the two pointed ears of a first end of a first bag and a rounded shape of the second end of an immediately adjacent bag. This can be achieved by an appropriately positioned cut or perforation cut line in the contiguous line of flexible bags.

A perforation cut line can be formed in any manner apparent to the person skilled in the art. Perforations of a perforation cut line may be substantially uniform or may have variable spacing and/or length of cuts along a width of a bag. For example, a perforation cut line may have variable spacing and/or length of cuts at laterally outer sides as compared to a laterally central portion.

A contiguous line of bags according to the present invention may be provided as a roll or in any other appropriate form.

Further features and advantages of the present invention will be apparent from the embodiments shown in the Figures and shown below. Drawings

Figure 1 shows an individual bag according to a first embodiment of a bag according to the present invention;

Figure 2 shows a contiguous roll of bags according to the first embodiment of the present invention;

Figure 3 shows an individual bag according to the present invention with its pointed ears tied in a knot;

Figure 4 shows part of a first end of a second embodiment of a bag according to the present invention;

Figure 5 shows part of a first end of a third embodiment of a bag according to the present invention;

Figure 6 shows a fourth embodiment of a bag according to the present invention;

Figure 7 shows the first embodiment of a bag according to the present invention in position in a bin;

Figure 8 shows a fifth embodiment of a bag according to the present invention in position in a bin;

Figure 9 shows the fourth embodiment of a bag according to the present invention opened out;

Figure 10 shows part of a first end of a sixth embodiment of a bag according to the present invention;

Figure 11 shows the first embodiment of the present invention opened out; and

Figure 12 shows a seventh embodiment of a bag according to the present invention.

Various embodiments of bags 1 according to the present invention are shown in the Figures and described below. Unless otherwise indicated by context or in the claims any feature of any of the embodiments of the invention can be included in any other embodiment of the invention. The description of the embodiments not intended to be limiting. The invention is defined in the claims. Figure 1 shows a first embodiment of a bag 1 according to the present invention. The bag 1 is formed of a flat tube of flexible polyethylene and is open at a first end 2 and sealed at a second end 3. The second end 3 of the bag 1 is curved. Two pointed ears 4 are provided at opposing lateral sides of the first end of the bag. Each of the pointed ears 4 is formed of two layers of polyethylene and are wider at a proximal end 5 than at a distal end 6. A distal portion 7 of each ear 4 is welded together such that the two layers of the bag 1 are securely welded to one another. The welded distal portion 7 of each ear 4 is generally indicated in the ear by shading. However, it is to be understood that this is for clarity only, the welded portions of bags 1 according to the present invention will not be significantly darker than unwelded portions.

As shown in Figure 2, the bag 1 of Figure 1 may be formed as a contiguous line of bags and provided as a roll 8. A perforation line 9 is provided to define the upper end 2 of each bag 1. A weld line 10 is provided to seal the second end 3 of each bag. Individual bags 1 can be removed from the roll 8 by tearing along the perforation line. As can be seen in the Figure, the shape of the first end 2 of a first bag 1 conforms to the shape of the second end 3 of an immediately adjacent bag 1. This is because the perforation line 9 defines the shape of both the first end 3 of the first bag and the second end 3 of the immediately adjacent bag.

Figure 3 shows a bag 1 according to Figure 1 and Figure 2 tied in a knot 11 after use. This is achieved by tying the ears 4 of a bag in a knot 11, preferably a double knot, to close the first end 2 of the bag 1. The second end of the bag 3 remains sealed.

The bag 1 of Figures 1 to 3 is advantageous in that it provides handles for the bag when it is in use. Conforming the first end 2 of one bag 1 to the second end 3 of an immediately adjacent bag eliminates the need to remove large handle cut outs that traditional carrier bag necessitate. The ears 4 can be used to tie the bag in a knot 11 as shown in Figure 3. Further the welding of the ears 4 improves the resilience of the handles and allows the bag to conform better to the upper end of a bin, as described below. In particular, welding the ears 4 provides a slight throat restriction/grip around the rim of a bin. The rounded second end 3 of the bag allows the bag 1 to conform better to the bottom of a bin when in use without wasted corners. Figure 11 shows the bag of 1 to 3 opened out.

The welded portions 7 of the bags 1 can be achieved using a welding bar (not shown) and can be welded at the same time as the weld line 10 in a single process.

Figures 4, 5, 10, and 12 show alternative embodiments of bags 1 according to the present invention. Only one lateral side of the first end 2 of the bag 1 is shown in these Figures. However, it is to be understood that these bags 1 are laterally symmetrical and the second end 3 of the bags 1 is substantially as shown in Figures 1 to 3.

The bag 1 of Figure 4 has an aperture 12 formed through each of the ears 4. The apertures 12 are welded around an outer circumference to weld the layers of the ears together such that the grip/restriction functionality and the handles remain reinforced. The apertures 12 can also allow the ears 4 to be tied in a knot more easily. The bag 1 of Figure 5 is substantially the same as the bag of Figure 4. However, the weld 7 is only provided in a horseshoe shape around the aperture 12.

The bag of Figure 10 also has an aperture 12 formed through each of the ears 4. However, unlike the embodiment of Figures 4 and 5, the aperture is simply provided through a lower end of a welded portion 7 of the ear 4. The welded portion 7 is the same as and provided in the same manner as in the embodiments of Figures 1 to 3. The additional aperture 12 facilitates the ears 4 being tied in knots and can help mount the bag 1 in bins 14, as described below.

The bag of Figure 12 has a cutaway portion 15 provided immediately below the welded portion 7 at a laterally outerside. This functions in the same manner as the aperture 12 of the embodiment of Figure 10 as it facilitates the ears being tied in knots and/or the carrying of the bag 1. Figure 6 shows a fourth embodiment of a bag 1 according to the present invention. The bag 1 is substantially the same as the bag 1 of Figure 1 with the exception that folded portions 13 are provide at each lateral side of the bag 1. This reinforces the lateral sides of the bag 1 and the ears 4 and also provides greater capacity for the bag 1 as the folded portions 13 can expand when the bag is in use. The ears 4 of this embodiment comprise four layers and, as such, are more robust than in other embodiments. Figure 9 shows the bag 1 opened out to show the greater volume of the bag when it is expanded.

Figure 7 shows the first embodiment of a bag 1 according to the present invention, as shown in Figures 1 to 3, in use in a bin 14. The bag 1 is placed within the bin 14 and the ears 4 are folded over the upper end of the bin in the manner shown in the Figures the welded portions 7 of the ears provide a restriction to the first end of the bag 1 and help the bag 1 stay in position and not fall down the bin 14 when in use. The bag 1 of Figure 8 further comprises apertures 12 that an be used to mount the bag 1 on protrusions 15 of the bag 1.