GB2390078A

GB2390078A - Easy-open bag with valve filling mean

Info

Publication number: GB2390078A
Application number: GB0314442A
Authority: GB
Inventors: Ian John Smith; John Joseph Dermot Griffiths; Patrick Thomas Connelly; Paul Stuart Brassington
Original assignee: Flexipol Packaging Ltd
Current assignee: Flexipol Packaging Ltd
Priority date: 2002-06-20
Filing date: 2003-06-20
Publication date: 2003-12-31
Anticipated expiration: 2023-06-20
Also published as: WO2004000670A1; AU2003253086A1; GB0314442D0; GB2390078B; GB0214226D0

Abstract

A plastics bag 10 for food storage comprises two walls 12, 14 joined along their sides, and a mouth 16 in one wall 12, covered by a closure flap 18. The closure flap is attached to a face of the bag in at least two regions 20, 24, one on either side of the mouth, and can either be peelably attached to the face in one of the regions, or provided with lines of weakness, to allow access to the mouth. The bag is provided with an access means for filling, comprising an incision 64 in the front wall 12 and a corresponding incision 62 in the closure flap, with a plastics sealing web 66 joined to the front wall and disposed between the two incisions. A third region of attachment 22 may also be provided. The mouth 16 may be a line of weakness which can be ruptured to form a mouth. The bag may incorporate gussets at either end to allow for the volume of contents.

Description

Improvements in Valve Sacks The present invention relates to bags and

sacks, and especially to plastic bags and sacks which are adapted for use with flowable products such as powders and 5 granular materials. The bags of the invention combine a closure which is easily opened when desired to provide access to the contents of the bag and which closure avoids contamination of the contents of the bag during opening. The bags of the invention have wide application for products in powdery or granular or like form, including, for example, masterbatches, pharmaceutical products ingredients and 10 precursors, pet and animal foods, prepared and partially prepared food products and food ingredients for human consumption and horticultural and agricultural products.

Many conventional closures require, for example, cutting of the plastic material of the bag or of stitching which closes the bag in order to gain access to the interior.

Constructions of this type are inherently open to the danger of leaving shards of cut 15 material in the bag contents. This sort of contamination is unacceptable, especially where the bags are used for food use or use with products in the pharmaceutical industry. The bags of the invention combine a closure which avoids the above contamination problems with the ability to fill the bag with the flowable product through a filling nozzle without disturbing the closure.

A closure which avoids contamination of the contents of the bag whilst being easily openable is described in GB 2 339 187. The bag described in this reference is provided with a completely open end through which the bag can be filled, the open end being subsequently sealed. The present invention seelcs to provide a bag which 25 has the easily openable advantages of the closure described in GB 2 339 187 and which is adapted for filling with a Plowable material by means of a filling pipe or nozzle. According to a first aspect of the present invention there is provided a plastic bag 30 comprising: first and second walls forming respective front and rear faces of the bag; a first closed end and a second closed end; a mouth for access on opening of the bag to the interior of the bag;

a closure flap, overlying and closing the mouth and having a first attached region which is peelably attached to the front face such that at least a portion of the closure flap may be peeled away from the front face across the peelably attached region to reveal the mouth, and a second attached region spaced from the peelably S attached region in which second region the closure flap is also attached to the front face; a filling region comprising a first incision formed in the closure flap and a second incision formed in the first wall, a plastic sealing web disposed between the closure flap and the first wall and, with respect to the closure flap, between the first 10 and second regions, the sealing web at least partially covering the second incision and being displaceable by an implement penetrating the first incision to reveal the .. second Incision.

According to a second aspect of the invention there is provided a plastic bag 15 comprising: first and second walls forming respective front and rear faces of the bag; a first closed end and a second closed end; a mouth for access on opening of the bag to the interior of the bag; a closure flap, overlying and closing the mouth and having a first region 20 which is attached to the front face, the closure flap including at least one line of weakness defining a tearable portion of the flap which does not include any part of the region which is attached to the front face and which portion can be opened by tearing along the line of weakness to reveal the mouth of the bag; and a second attached region spaced from the tearable portion region in which second region the 25 closure flap is also attached to the front face; and a filling region comprising a first incision formed in the closure flap and a second incision formed in the first wall, a plastic sealing web disposed between the closure flap and the first wall and, with respect to the closure flap, between the first and second regions, the sealing web at least partially covering the second incision 30 and being displaceable by an implement penetrating the first incision to reveal the second incision.

Preferably in these aspects of the invention, on respectively peeling back the peelable portion of the closure flap or tearing back the tearable portion, the front face remains substantially functionally intact 5 Preferably, the mouth comprises a slit formed in the first wall.

In a particularly preferred arrangement the closure flap is further attached to the front face in a third region, the first and third regions being disposed on respective sides of the mouth and the third region being disposed between the mouth and the second 10 attached region.

In another preferred arrangement, the sealing web is coextensive in width with the first side wall. Preferably the sealing web is attached to the front face at or adjacent the second attached region.

Preferably the first incision comprises a cut in the closure flap substantially parallel to the end of the bag. The second incision may be a cut in the form of a straight line, or a V-shaped incision, or intersecting straight incisions, forming an X shape, or the second incision may be a curved or arcuate incision, or three incisions joined at their 20 ends to form a C or U shape. The first and/or second incisions may initially be in the form of a line, or lines, of weakness which are ruptured or torn to form the incision.

In a particularly preferred embodiment of the invention, the bag is constructed to provide a flat stable base at one or both ends on which the bag can stand without 25 support when filled with it contents. In this embodiment, the first and/or second closed end comprises in a first, folded, configuration: a base panel, connected on opposing sides thereof to respective end edges of the first and second walls; a first fold formed in the base panel, substantially coextensive with the width of 30 the walls and substantially parallel to the end edges, said fold dividing the base panel into first and second panel leaves, the first fold and the panel leaves lying between said walls with the external faces of the panel leaves towards each other; and

seal lines along which the first and second walls are respectively joined to the base panel, one of said seal lines extending from each end of the first fold to each end edge at a point spaced, with respect to the width of the bag, from the respective end of the first fold.

s Preferably the seal lines are heat seals. Preferably also, the sealing web partially overlies the panel leaves.

The bag with this construction may alternatively be defined in its expanded 10 configuration in which the first and/or second closed end comprises: a generally rectangular base portion having opposed side edges connected to and co-extensive with respective end edge portions of the first and second walls, and opposed end edges; and generally triangular end wall portions each depending along a base side thereof 15 from a respective end edge of the base panel, having an apex positioned in use above the base panel and having side edges extending between the apex and respective corners of the base portion along which side edges of the triangular end wall portions the first and second walls are joined respectively to said end wall portions.

In another variation of the invention the first wall comprises a line of weakness which is ruptured to provide the mouth.

Where the closure flap is peelably attached to the front face, the closure flap 25 preferably includes one or more lines of weakness along which the closure flap may be torn, said lines of weakness defining the portion of the closure flap which may be peeled away to reveal the mouth.

For a better understanding of the invention and to show how the same may be carried 30 into effect, reference will now be made, by way of example only, to the following drawings in which: Figure 1 a is a schematic plan view of a bag according to the invention;

Figure lb is a schematic plan view of a preferred variation of the bag of I Figure la; Figure lc is a schematic plan view of another variation of the bag of Figure la; 5 Figure 2a is a schematic section through the bag of Figure la; Figure 2b is a schematic section along the line II-II through the bag of Figure lb; Figure 2c is a detail of Figure 2b on an enlarged scale; Figure 3 illustrates a base part of the bag in an expanded condition; 10 Figure 4 is a schematic section through an alternative embodiment of the bag according to the invention; and Figure 5 is a partially cut-away plan view of a bag according to the invention similar to that of Figure la.

15 Referring now in particular to Figures la and 2a, the bag (10) of the invention i comprises a front wall ( 12) and a rear wall (14). The front wall ( 12) and the rear 5 wall (14) are joined together along their side edges (26), such as by a heat weld. In one possible variation, the front and rear walls (12), (14) are formed integrally from a tube, the walls (12), (14) then being continuous with no actual joint between them.

20 End edges (28) of the walls (12), (14) are also closed. The closure at end edges (28) may be a simple adhesive or heat seal as in Figure 2a or may be a more complex structure as described below with reference to Figures 2b and 2c.

One end of the front wall (12) is covered by a closure flap (18). The front wall (12) 25 includes a mouth (16) which lies below the closure flap (18) and is therefore indicated in Figure la by a dotted line. The mouth (16) may take the form of a line of weakness in the front wall (12) which is ruptured when required to form the mouth (16). The closure flap (18) is attached to the front face of front wall (12) in regions (20), (22) and (24) and hence provides a closure for the mouth (16). Region (22) is 30 optional, but is preferably present. In regions (22) and (24) the closure flap (18) is preferably permanently attached to the front wall( 12) such as by a heat weld or by

permanent adhesive. Permanent adhesive is preferred. As an alternative a non-

permanent adhesive such as a peelable adhesive could be used for regions (22), (24).

Region (20) comprises a region in which the closure flap (18) is attached to the front 5 face ofthe front wall (12) by means such that a user can grasp the leading edge (30) of the closure flap (18) and peel the closure flap (18) away from the front wall (12), leaving the front wall (12) functionally intact. The front wall (12) may be distorted by the peeling away of the closure flap (18) but is not substantially torn or ruptured.

By peeling back the closure flap (18) the mouth (16) is exposed so that the user may 10 gain access to the contents in the interior of the bag. The region (20) may in general be provided by any suitable means such as a peelable adhesive or a peelable heat weld or seal. A peelable adhesive is much preferred. As can be seen from Figure 5, the region 20 may comprise two or more lines of peeleble adhesive. The region (20) of peelable adhesive may be such as to allow the closure flap (18) to be re- adhered to 15 the front wall (12) after it has been peeled away. When present, the region (22) will preferably act to limit the extent to which the closure flap (18) may be peeled back.

In some constructions, the peelable region (20) may not extend across the whole width of the front wall (12). Thus, the closure flap (18) may be provided with lines of weakness (32) extending from the leading edge (30) towards the mouth (16) along 20 which the closure flap may be torn. In this case it is necessary only for the region (20a) bounded by the lines of weakness to be peelably attached to the front wall (12).

Outside this region (20a), the closure flap (18) may be attached to the front wall by any suitable means, such as peelable or non-peelable adhesive or a permanent heat seal or weld.

The lines of weakness (32) may preferably be straight and substantially parallel to side edges (26) as illustrated in Figure la, or may take other forms. The lines of weakness (32) may be at an angle to the side edges (26), or may be curved. A single line of weakness having a curved path with its ends near the mouth (16) and 30 extending through the peelably attached region (20a) is a further alternative. In this case, the line of weakness need not extend to the leading edge (30). In another form, the line of weakness may comprise a series of connected straight or curved lines

beginning near the mouth (16) towards one side edge of the closure flap (18), extending through the peelably attached region (20a) and back to the mouth ( 16) towards the other side edge of the closure flap (18).

5 By means of the above construction, an effective closure is provided over the mouth of the bag by means of which the contents of the bag are safely and securely retained within the bag. Importantly, the closure can be opened without the need for any cutting or (other than specifically along the lines of weakness) any tearing steps which might generate shards of plastic or other material which could contaminate the 10 contents of the bag. In the Figures, the closure flap (18) is shown positioned towards one end ofthe bag. This is not essential and in principle the closure flap (18) (and associated structures below the closure flap (18) such as the mouth (16) and peelable region (20)) may be positioned anywhere on the front wall (12). Positioning of the closure flap (18) toward one end of the bag is nevertheless preferred Figure 1 c illustrates a variation of the construction shown in Figures la and 2a which does not require the use of a peelable region for displacement of the closure flap (18) to reveal the mouth ( 16) In the embodiment illustrated in Figure 1 c. The closure flap includes at least one line of weakness (38) which divides the closure flap into 20 first and second regions (34), (36). In the region (34) the closure flap (18) is attached to the front face of first wall (12) by suitable means such as a permanent adhesive or heat weld or seal. It is not necessary for the closure flap ( 18) to be attached throughout the whole of the region (34), provided only that an effective closure is achieved. For example, the closure flap ( 18) may be attached only around 25 the boundaries of the region (34), shown as 34' and 34" in Figure lo. Region 34" may typically be an adhesive region. Regions 34' may typically be heat welds. In region (36), the closure flap (18) is not attached at all to the front face of first wall (12). Thus, the portion (36) ofthe closure flap (18) defined by the lines of weakness (38) can be torn back along the lines of weakness (38) to reveal the mouth, the 30 portion (34) remaining attached to the front wall (12). This construction therefore achieves the same effect in use as the construction in Figures la and 2a, but does not need the peelable adhesive region (20). The construction of Figures la and 2a is

nevertheless preferred for reasons including ease of manufacture of the bag. The construction of the remainder of the bag of Figure to can be the same as described in respect of Figures la and 2a (or Figures lb and 2b described below).

5 Referring now to Figures lb and 2b, these Figures show a preferred variation of the bag of the invention which is constructed to allow the bag to stand stably, when filled on one or other of its ends. The bag of Figures lb and 2b includes a front wall (12), a rear wall (14) as in Figures I a,2a and lo. The bag further includes one or two base panels (40). Two base panels (40) are shown in Figures lb and 2b, so that the bag 10 may stand stably on either end. The front wall (12) and rear wall (14) have bottom end edges (28) and are joined to the base panels (40) along folds (42) at the base end edges (28). The base panels (40) include a fold (44), indicated by a dotted line in Figure lb, by means of which the panel (40) is divided into two equal halves or panel leaves (46a, 46b) which then lie between the front and rear walls (12), (14). At the 15 ends of fold (M), that is at points X, the front and rear walls (12), (14) are joined to each other and to the base panel (40) by suitable means. Heat welding is preferred.

Adhesive is an alternative. Side edges (26) may similarly be joined to the corresponding side edges of the base panel or the side edges (26) and the side edges of the base panel may all be joined together in a single join. The latter construction 20 is preferred for ease of manufacturing. In this case a single heat weld adjacent the side edges may be used to join all the layers together (that is, the front and rear walls (12), (14) and the two panel leaves (46a, 46b)). Further joins (48, 50, 52, 54) are made between the front wall (12) and the adjacent part of the base panel (40).

Corresponding joins (48', 50', 52', 54') are made between the rear wall (14) and the 25 adjacent part of the base panel (40), these not being visible in Figurelb. These joins take the form of seal lines extending from the respective ends of the fold (44) to the base end edge (28) of the respective wall (12), (14). It may be noted that these joins (48, 48', 50, 50', 52, 52', 54, 54') join the front or rear wall (12), (14) to the base panel (30) but do not join the respective panel leaves (46a, 46b) together. The joins 30 (48, 48', 50, 50', 52, 52', 54, 54') are also preferably heat seals.

When the bag is filled, the product within the bag causes the bag to expand from the folded condition as manufactured which is illustrated in Figures lb and 2b to an expanded configuration. The expanded configuration of the base of the bag is illustrated in Figure 3. If the construction described above is provided at both ends 5 of the bag, the "top" end adjacent the closure flap is expanded similarly. To achieve the expanded configuration, the end points Y of the seal lines (48, 48', 50, 50') (52, 52' 54, 54') on the base end edges (28) of the walls (12), (14) are urged outwardly by the bag contents as the bag is filled. This causes a part of the base panel (40) to be opened out into a flat rectangular base portion (56) of which the four points Y form 10 the corners. End parts of the base panel (40) then form upstanding triangular end wall portions (58a, 58b) defined by points Y-X-Y and marginal parts or the walls (12), (14) are curved around to form the remainder ofthe end walls (60). The flat rectangular base portion allows the bag to stand stably and unsupported when filled with product.

Figure 4 illustrates a further variation of the bags of the invention in which the closure flap (18) depends from, and is preferably formed integrally with, the second wall (14). The end of the closure flap (18) forms a fold (70) by means of which it is connected to the second wall (14). Seals (72), (74) may provided respectively 20 sealing the closure flap( l 8) to the first side wall and sealing the first side wall to the second side wall. Other constructional details of the embodiment of Figure 4 correspond to those of Figures 1 and 2.

From the above it can be appreciated that the bags of the invention are supplied from 25 the manufacturer to the user in an essentially closed condition. For the avoidance of doubt, it is noted that it is not intended that the bags be filled with their contents by peeling/tearing back the closure flap (18) to fill through the mouth (16), thereby disturbing the closure. It is a particular advantage of the bags of the invention that the closure over the mouth remains undisturbed until it is required to remove 30 contents from the bag. To this end, the bag is provided with entirely separate means by which it can be filled without disturbing the closure over the mouth. These means provide relatively easy access for a filing pipe or nozzle to the interior of the bag and

also provide an effective seal for the bag after it has been filled with its contents.

The filling means can thus be regarded as acting as a valve. These means are essentially similar in all the embodiments illustrated in Figure l ac, 2a and 2b and will therefore be described with particular reference to Figures 1 a and 2a.

The filling means according to the invention comprises three parts, namely, an incision (62) in the front wall (12) of the bag, a correspondingly placed incision (64) in the closure flap (18) and a sealing web (66) disposed between the closure flap (18) and the front wall (12) which separates the two incisions (62), (64)so that they are 10 not normally in direct communication with each other. In other words, sealing web (66) is positioned to lie directly above the incision (62) in the front wall (12) and at least partially covering the incision (62) and incision (64) in the closure flap (18) is positioned to lie above both the incision (62) and the sealing web (66). Incision (64) in closure flap (18) need not be directly above incision (62) in front wall (12), but the 15 incisions (62), (64) must be sufficiently closely spaced to allow access to the interior of the bag by a filling pipe or nozzle, as described below.

Incision (62) in the closure flap (18) is preferably a straight line generally parallel to the end edge (28). Incision (64) in the front wall (12) is preferably a single straight 20 line at an angle with respect to the end edge (28), as shown by way of example in Figure l c. Typically the incision (64) will be at an angle of about 30 to about 60 with respect to the end edge (28). In an alternative construction, the incision (64) comprises two lines meeting at an angle (preferably an acute angle) thus forming a "V" shape and providing a triangular flap depending along the base of the triangle 25 from the remainder of the front face. The triangular flap is thus displaceable by the filling nozzle in use to gain access to the interior of the bag. Other types of incision are also possible, such as an X-shaped, C-shaped, U-shaped or arcuate incision.

Sealing web (66) is preferably made from relatively lightweight plastic film and is 30 preferably coextensive with the width of the bag. The web (66)is preferably attached to the front wall (12) at the side edges (26) of the bag. This is conveniently achieved by heat welding the side edges of the web (66) in the same weld which

joins the side edges (26) of the bag together. Sealing web (66) is also preferably attached to the front wall (12) along its top edge (68), suitably by an adhesive (68a).

Most preferably, the sealing web (66) is not attached to the front wall (12) at any other point. Although the sealing web (66) has been described as extending across 5 the full width of the front wall (12) this is for convenience of manufacture and is not essential to the invention. It is essential only that the sealing web (66) is of sufficient size that it at least partially covers the incision (62) in the front wall (12) and is attached in such a way that it may be displaced to reveal the incision (62) and subsequently returned substantially to its initial position. In the embodiment of 10 Figures lb and 2b, the sealing web (66) may be attached to the adjacent panel leaf (46a, 46b) by means of the respective seal line (48, 48', 5O,50').

In use of the bag of the invention, the intended contents of the bag are provided in Plowable form to a filling pipe or nozzle (hereinafter, filling nozzle). The filling 15 nozzle is inserted through the incision (64) in the closure flap (18) and is used to displace (with the possible assistance of the operator's hand) the sealing web (66) by its edge (66a) to reveal the incision (62) in the front wall (12). The filling nozzle can then be inserted through the incision (62) into the interior of the bag. The bag is filled with the Plowable contents through the filling nozzle. When the bag has been 20 filled to the desired extent, the filling nozzle is withdrawn and the sealing web returns substantially to its initial state covering the incision (62), which also closes.

An effective closure which retains the Plowable contents within the bag is thereby provided. This closure is made on withdrawal of the filling nozzle, is not unduly complex to produce, is inherently reliable and does not require any separate step to 25 provide a closure after filling. For example, it is not necessary to heat seal any orifice which has been used for the filling of the bag. However, should it be desired it is possible to apply a heat seal to the region around the incision (64) in the closure flap, so that the incision (64) is effectively closed, such heat sealing being possible without affecting the opening of the bag by means of closure flap (18).

The present invention is adapted for use with bags of a variety of sizes and purposes.

The bags are particularly well adapted for use in food manufacture and processing,

but other uses are not precluded. A typical bag might have a length of about 1 OOOmm and a width of about SOOmm. The closure flap would then have a depth of about 250mm with the sealing web having a depth of about lOOmm. These dimensions are for example only and the actual size of the bag and its components is 5 entirely selectable in accordance with the intended use. The size of the first and second incisions is selectable in accordance with the size of the filling nozzle with which they are intended to co-operate in use. Typically, Me incision in the closure flap might have a length of about 1 OOmrn with the distance between the ends of the lines of the V-shaped incision in the front wall being also about lOOrnm.

Claims

1. A plastic bag comprising: first and second walls forming respective front and rear faces of the bag; 5 a first closed end and a second closed end; a mouth for access on opening of the bag to the interior of the bag; a closure flap, overlying and closing the mouth and having a first attached region which is peelably attached to the front face such that at least a portion of the closure flap may be peeled away from the front face across the peelably attached 10 region to reveal the mouth; and a second attached region spaced from the peelably attached region in which second region the closure flap is also attached to the front face; a filling region comprising a first incision formed in the closure flap and a second incision formed in the first wall, a plastic sealing web disposed between the 15 closure flap and the first wall and, with respect to the closure flap, between the first and second regions, the sealing web at least partially covering the second incision and being displaceable by an implement penetrating the first incision to reveal the .. second incision.

20

2. A plastic bag comprising: first and second walls forming respective front and rear faces of the bag; a first closed end and a second closed end; a mouth for access on opening of the bag to the interior of the bag; a closure flap, overlying and closing the mouth and having a first region 25 which is attached to the front face, the closure flap including at least one line of weakness defining a tearable portion of the flap which does not include any part of the region which is attached to the front face and which portion can be opened by tearing along the line of weakness to reveal the mouth of the bag; and a second attached region spaced from the tearable portion region in which second region the 30 closure flap is also attached to the front face; and a filling region comprising a first incision formed in the closure flap and a second incision formed in the first wall, a plastic sealing web disposed between the

closure flap and the first wall and, with respect to the closure flap, between the first and second regions, the sealing web at least partially covering the second incision and being displaceable by an implement penetrating the first incision to reveal the second incision.

3. A plastic bag as claimed in claim l or 2 wherein the mouth comprises a slit formed in the first wall.

4. A plastic bag as claimed in claim 3 wherein the closure flap is further 10 attached to the front face in a third region, the first and third regions being disposed on respective sides of the mouth and the third region being disposed between the mouth and the second attached region.

5. A plastic bag as claimed in any preceding claim wherein the sealing web is 15 coextensive with width of the first side wall.

6. A plastic bag as claimed in any preceding claim wherein the sealing web is attached to the front face at or adjacent the second attached region.

20

7. A plastic bag as claimed in any preceding claim wherein the first incision comprises a cut in the closure flap substantially parallel to the end of the bag.

8. A plastic bag as claimed in any preceding claim wherein the second incision comprises a V-shaped incision.

9. A plastic bag as claimed in any preceding claim wherein the first and/or second closed end comprises in a first, folded, configuration, a base panel, connected on opposing sides thereof to respective end edges of the first and second walls, a first fold formed in the base panel, substantially coextensive with the width of the 30 walls and substantially parallel to the end edges, said fold dividing the base panel into first and second panel leaves, the first fold and the panel leaves lying between said walls with the external faces of the panel leaves towards each other, and

seal lines along which the first and second walls are respectively joined to the base I panel, one of said seal lines extending from each end of the first fold to each end edge at a point spaced, with respect to the width of the bag, from the respective end of the first fold.

10. A plastic bag as claimed in claim 9 wherein the seal lines are heat seals.

11. A plastic bag as claimed in claim 9 or claim 10 wherein the sealing web partially overlies the panel leaves.

12. A plastic bag as claimed in any of claims 1 to 8 wherein the first and/or second closed end comprises in a second, expanded configuration a generally rectangular base portion having opposed side edges connected to and co extensive with respective end edge portions of the first and second walls, and 15 opposed end edges, generally triangular end wall portions each depending along a base side thereof from a respective end edge of the base panel, having an apex positioned in use above the base panel and having side edges extending between the apex and respective corners of the base portion along which side edges of the triangular end wall portions the 20 first and second walls are joined respectively to said end wall portions.

13. A plastic bag as claimed in any preceding claim wherein the first wall comprises a line of weakness which is ruptured to provide the mouth.

25

14. A plastic bag as claimed in any preceding claim wherein where the closure flap is peelably attached to the front face, the closure flap includes one or more lines of weakness along which the closure flap may be torn, said lines of weakness defining the portion of the closure flap which may be peeled away to reveal the mouth.;

15. A plastic bag substantially as hereinbefore defined with reference to any of Figures la, lb, lo, 2a, 2b, 2c and 3 to 5.