NZ214302A - Plastics bag with pressure-sensitive adhesive to seal closure flap against lip edge - Google Patents

Description

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PATENTS FORM NOt 5 Fee No. 1 & 4:$145.00 PATENTS ACT 1953 COMPLETE SPECIFICATION TITLE: "SECURITY BAG" We TRIGON PACKAGING SYSTEMS (NZ) LIMITED a New Zealand company of Corner Avalon Drive and F ore man Road, Hamilton, New Zealand. hereby declare the Invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 214302 This invention relates to a security bag.

It is known to provide security bags of synthetic plastics film material each comprising front and rear panels one of which has a flap which is foldable onto an outer surface of the other panel to close the bag and in which there is provided pressure sensitive contact adhesive for uniting the folded flap with the adjacent surface of the other panel.

It has been found that by carefully applying a solvent under the flap when bonded to the adjacent surface, the effect of the adhesive can be neutralised permitting the flap to be separated from the adjacent surface.

The bags are therefore not tamper evident because, after having applied solvent to the adhesive of a bag to nullify the effect thereof and thereby open the bag, contents may be removed and the flap re-united with the opposite facing surface of the bag by means of fresh pressure sensitive adhesive subsequently applied to the flap and/or the portion of the surface subsequently covered by the flap.

It is desirable, therefore, to provide a bag which cannot be opened without severing the material of the bag.

According to the present invention, there is provided a bag comprising front and rear panels one of which has an outwardly turned lip extending adjacent an opening of the bag and the other of which has a flap foldable onto the lip and pressure sensitive adhesive for uniting the flap to the lip and to an outer surface of the panel having the lip, the arrangement being such that, when the flap is peeled from the said outer surface, the lip remains united with the flap.

The adhesive may be provided in two portions wherein one of the portions is located so as to unite the flap with the lip and the other of the portions is located so as to unite the lip with the said outer surface of the panel having the lip.

The flap may be provided with a weakened portion. 2 14302 The weakened portion may comprise a row of slits.

The flap may be provided with an extended portion adapted to be separated from the flap.

The material of the bag may be adapted to receive indicia. " ijf' The material may be adapted to receive indicia by having located thereon an indicia receiving zone extending from the flap to the extended portion.

The material may be a co-extruded thermoplastic material a surface of which is ^ capable of receiving indicia thereon.

The flap may be a component additional to material comprising the panels.

A surface of the material may be treated with a substance for receiving a component having a pressure sensitive adhesive thereon for uniting with the surface.

Following is a description, by way of example only and with reference to the accompanying drawings, of one method of carrying the invention into effect.

In the drawings:- Fiqure 1: is a diagrammatic perspective view of the rear of one embodiment of a bag in accordance with the present invention, the bag being in an open unused condition, Figure 2: is a perspective view of the front of the bag when in an open unused condition, and Figure 3; is a perspective view of the rear of the bag when in a closed condition. Referring to the drawings, there is shown a bag 10 comprising a sheet of synthetic 2 14302 plastics film material which is folded at 11 to provide a front panel 12 and a rear panel 13, the panels being welded one to another in spaced parallel side welds 14, 15, extending at right angles to the fold 11. The material is folded such that the front panel extends beyond the rear panel in a longitudinal direction of the side welds 14, 15 to provide an extended portion 16, and the material is provided with a pair of spaced parallel rows of slits 17, 18 extending transversely of the extended portion 16 and substantially parallel to the fold 11. The portion extending from the row of slits 18 to an edge of the extended portion 16 remote from the fold 11 defines a tear off strip 19.

A portion of the rear panel 13 remote from the fold 11 is folded outwardly upon itself to provide a transversely extending lip 20 which is united with an outer surface of the rear panel 13 by a strip of pressure sensitive contact adhesive 21 extending transversely of the rear panel 13.

The extended portion 16 has applied to a rear surface thereof a strip of pressure sensitive contact adhesive 22 which extends transversely of the extended portion 16 and in a direction from a location adjacent the fold of the lip 20 to a location adjacent the row of slits 18. The adhesive 22 is covered by a backing strip 23, coated with a release substance, such as silicone, on a surface thereof which contacts the adhesive 22.

A front surface of the extended portion 16 has printed thereon two identical numbers 24, 25 located on opposite sides of the row of slits 18. The front surface of the extended portion 16 also has printed thereon a stripe 26 on which information can be written, the stripe 26 extending across the rows of slits 17, 18.

In use, articles are inserted in the bag 10 by, or under the supervision of, a person authorised to do so. The authorised person signs his or her signature on the stripe 26 so that the signature extends across the rows of slits 17, 18. The tear off strip 19 is then severed from the extended portion 16, along the row of slits 18 and the tear off strip 19, bearing a portion of the signature written on the stripe 26, is stored.

I14JU- The remaining portion of the extended portion 16 extending beyond the lip 20 in a direction away from the fold 11 comprises a flap 27 bearing the adhesive 22 on a rear surface thereof and the backing strip 23 covering the adhesive 22.

The backing strip 23 is peeled from the adhesive 22 on the flap 27 and the backing strip 23 is peeled from the portion 21 of the adhesive 20 thereby exposing the portion 21 of the adhesive, the lip 20 still being united with an opposite facing surface of the rear panel 13 by the remaining portion of the adhesive 20.

The flap 27 then is folded rearwardly onto the lip 20 with a result that the adhesive 22 on the flap 27 unites with the lip 20 whereby the flap 27 is sealed to the lip 20 and to the outer surface of the rear panel 13 thereby effecting closure of the bag 10 and enveloping the contents therein.

The bag 10 subsequently is opened by severing the material of the bag 10 in a direction substantially parallel and adjacent to the fold 11, as indicated in figure 3.

If an attempt is made to open the bag 10 by lifting the flap 27 from the outer surface of the rear panel 13, the dual adhesive bonding of the flap 27 with the lip 20 and of the lip 20 with the outer surface of the rear panel 13, enhances resistance to the lifting force with a result that the material of the bag 10 bridging the slits of the row 17 is severed.

Since it is difficult to align the material of the bag 10 to reconstitute the row of slits 17, any attempt to replace the severed portion of the flap 27 after pilferage of the contents of the bag would be apparent.

Preferably, however, the bond between the flap 27 and the lip 20 is greater than between the lip 20 and the outer surface of the rear panel 13.

If, therefore, the flap 27 is lifted from the outer surface of the rear panel 13, the lifting action still would not result in peeling of the flap 27 from the lip 20 and 2 14302 opening of the bag 10. Such differential bonding may be achieved by using three ply co-extruded plastics film material whereby the surfaces of the flap 27 and the lip 20 which will unite with one another, provide a more substantial bond with the adhesive 22 than the opposite facing surface of the lip 20 and the rear panel 13 bonded by the adhesive 21. Alternatively, the adhesives 21 and 22 may be different so as to provide differential bonding of the respective surfaces.

Apart from being resistant to a force lifting the flap 27 from the outer surface of the rear panel 13, the bag 10 is resistant to application of solvent if used to attempt to open the bag 10 at the flap 27. If a solvent is deposited between the flap 27 and the adjacent outer surface of the rear panel 13, the solvent may neutralise the bonding effect of the adhesive 21 uniting the lip 20 with the remaining portion of the rear panel 13 but, due to the more effective bond between the flap 27 and the lip 20, the solvent will not break down the adhesive 22. In consequence, it may be possible, using a solvent, to peel the flap 27 from the outer surface of the rear panel 13 but such action would not result in opening of the bag 10.

It will be appreciated that a security bag in accordance with the present invention may be provided using different combinations of the features specified above. For example, a film material which is easily severed, such as polyethylene, may be used with a slip additive. The material may be stored such that the slip additive migrates to the surface of the material which will constitute the outer surface of the rear panel 13 of bags 10 made from the material. In consequence, the surface embodies a greater percentage of slip additive than the opposite surface of the material which will receive the adhesive 22 which will unite the flaps 27 and the lips 20 of the respective bags 10. The effectiveness of a bond between two surfaces united by adhesive varies inversely with the greater the percentage of slip additive present at the or each surface. In such a case, it is possible that the row of slits 17 may be omitted since the material is easily severable.

Alternatively, if stronger material is used or material which comprises a plurality of layers of different characteristics is used, the row of perforations 16 is likely to be necessary as is possible treatment of one or both of the opposite facing surfaces of 2 3 4302 the material such as by subjecting the material to electric corona discharge to ensure effective and/or differential bonding of the adhesive 20 and/or 22 with the surface or surfaces in contact therewith.

It will also be appreciated that the tear off strip 19 and the stripe 26 provide added security features. The tear off strip 19, in being provided with a number identical with the number on the bag, can be traced to identify the authorised person who signed the stripe 26 and removed the tear off strip 19. Furthermore, the fact that a signature is written across the rows of slits 17, 18 not only provides a security feature in that difficulty would be experienced in perfectly realigning portions of a signature in reconstituting the row of slits 17, but also a fraudulently prepared tear off strip 19 is unlikely to be perfectly matched with a bag 10 such that a portion of a signature on the fraudulently prepared tear off strip 19 would correspond with a portion of a signature on the bag 10.

Furthermore it will be appreciated that the flap 27 having the tear off strip 19 may be an additional component which is united with the front panel 12 by means of adhesive or heat seal. The flap 27 may be of transparent material and the tear off strip 19 may also be of transparent material.

It will also be appreciated that an outer surface of the bag 10 may be treated with a substance for receiving a component, such as a postal stamp, having a pressure sensitive adhesive thereon for uniting with the surface. 214302

Claims (11)

WHAT WE CLAIM IS;

1. A baq comprising front and rear panels one of which has an outwardly turned lip extending adjacent an opening of the bag and the other of which has a flap foldable onto the lip and pressure sensitive adhesive for uniting the flap to the lip and to an outer surface of the panel having the lip, the arrangement being such that, when the flap is peeled from the said outer surface, the lip remains united with the flap.

2. A bag as claimed in claim 1 wherein the adhesive is provided in two portions, one of the portions beinq located so as to unite the flap with the lip and the other of the portions being located so as to unite the lip with the said outer surface of the panel having the lip.

3. A baq as claimed in claim 2 wherein at least one of the panels is provided with a weakened portion.

4. A bag as claimed in claim 3 wherein the weakened portion comprises a row of slits.

5. A bag as claimed in any one of the preceding claims wherein the flap is provided with an extended portion adapted to be separated from the flap.

6. A bag as claimed in any one of the preceding claims wherein material of the bag is adapted to receive indicia.

7. A bag as claimed in claim 6 wherein the material is adapted to receive indicia by having located thereon an indicia receiving zone extending from the flap to the extended portion.

8. A bag as claimed in any one of the preceding claims-Jadierejn material of the bag is co-extruded thermoplastics material a surface of which is capable ofl receiving indicia thereon. / 'v ^'v\ -iltfy?''- £'v -v--. .-. --T . . *... .„. ■* *-c *•■ '•" -v ""* ' ^-.-^^'.MSf 2 14302

9. A bag as claimed in any one of the preceding claims wherein a surface of material of the bag is treated with a substance for receiving a component having a pressure sensitive adhesive thereon for uniting with the surface. _yj

10. A bag as claimed in any one of the preceding claims wherein the flap is a component additional to material comprising the panels.

11. A bag substantially as hereinbefore described and as illustrated in the accompanying drawings. TRJGON PACKAGING SYSTEMS (NZ) LIMITED by their Attorneys BARRY V. JAMES A ASSOCIATES -9-