GB2145997A - Tamperproof bag - Google Patents

Abstract

A substantially tamperproof bag, for example for bank notes, has overlying walls 12, 13 of synthetic plastics with an open end for insertion of goods. At least one wall has at or adjacent the open end an adhesive portion 18 temporarily covered by a peelable strip 20, at least part of the adhesive portion being overlaid by the opposite wall before the bag is sealed. The adhesive is selected so that, when the peelable strip is removed and the bag sealed, the package so formed can only be opened with destruction or distortion of the synthetic plastics. <IMAGE>

Description

SPECIFICATION Bags This invention relates to bags and is particularly concerned with security bags such as those intended to contain bank notes.

Bank note bags, made of a synthetic plastics material such as polyethylene are commonly used in banks for the movement of bundles of notes. Such bags are filled with a predetermined number of notes and the bag sealed by the bank, for example by heat sealing, before its transfer elsewhere. The bag is not opened until at its final destination and access to the contents is only possible by rupturing the plastics material. Tampering with the filled bags is thus prevented as, once ruptured, the bag cannot be satisfactorily resealed. Further security measures to discourage tampering may also be taken, such as the application of "micro-security printing" to the sides and ends of the bags to ensure detection if an attempt should be made to cut a side or end of the bag and then reseal it.

The bank must have special equipment such as a heat sealer in order to close each bag efficiently once it has received its complement of bank notes.

This adds to the bank's costs in using such bags and it also means that the bag filling can only take place at a station adjacent to a heat sealing device.

The present invention seeks to overcome these difficulties.

According to this invention we provide a bag, intended in use to provide a tamperproof package, the bag being formed of overlying walls of synthetic plastics material and having an open end for insertion of goods to be packaged, at least one wall having at or adjacent the open end an adhesive portion temporarily protected by a strip of peelable material, at least part of the adhesive portion being overlaid by the opposite wall before the bag is used and the adhesive being a selected so that, when the peelable strip is removed and the bag sealed by causing the adhesive to seal against the opposite bag wall, the package so formed cannot be opened along the seal without destruction or distortion of the synthetic plastics material.

Preferably the adhesive portion on one wall extends beyond the opposite wall at the open end of the bag so that when the peelable strip is removed a second seal can be formed by folding over the extension onto the outside of the opposite wall, to give double seal-security.

The adhesive may suitably be of a material such as Steratape 103/F (supplied by Sterling Adhesive Materials Limited). The peelable strip may be of any suitable release paper or the like.

Preferably the bag has a length greater than its width with the two walls being formed from a single strip of plastics material folded in such a manner that one end of the bag is constituted by a fold of the strip and the other, open end, by the ends of the strip, the walls being sealed together by seals adjacent their longer side edges. Such bags may conveniently be manufactured as described and claimed in our Patent Specification No. 2009707B.

Preferably the wall seals are spaced from the side edges and the skirts so formed bear micro-security printing. Preferably micro-security printing is also provided adjacent the open end of the bag, where in use a seal will be formed.

As a further preferred feature, to give improved security to the closed bag, micro-perforations may be applied to the bag on or adjacent the ends of the walls which effect the seal. Such micro-perforations weakens the material covered by the adhesive so that any attempt to tamper with the seal would destruct the bag material.

The invention will now be described by way of example with reference to the accompanying drawing in which Figures 1 and 2 are respectively a plan view of the bag and a section on the line ll-ll of Figure 1; and Figures 3 and 4 are modifications of the section shown in Figure 2.

The bag shown in Figures 1 and 2 is made of a single strip of polyethylene film which is folded on itself to form two overlying walls 12, 13. One end of the bag is therefore formed by the fold at 14 while the other, open, end is formed by the ends of the strips. The walls are heat-sealed together along lines 15, 16 which are parallel to, but spaced from the side edges, i.e. the longer edges, of the walls, narrow skirts 17 remaining between the seal lines 15 and 16 and the side edges.

When the bag is intended to receive a bundle of bank notes, the length of the bag between the end 14 and the open end, and the width of the bag between the seal lines 15 and 16 are somewhat greater than the corresponding dimensions of the bank notes for which the bag is intended, so that a bundle of notes can be conveniently inserted in the bag. To facilitate the reception of such a bundle the end 14 may be made with a gusset (not shown).

The ends of the walls 12 and 13 do not exactly overlie one another. Instead the end of wall 12 projects beyond the end of wall 13 to provide a lip 18. The lip 18 and adjacent portion of wall 12 overlaid by wall 13 up to the line marked 19 in Figure 1 is coated with a suitable adhesive. To protect the adhesive until it is to be used to seal the bag, it is covered with a peelable strip 20. Once the bank notes are in position, the strip 20 can be readily removed to expose the adhesive and the edges of walls 12 and 13 at the open end of the bag squeezed together to seal them. The projecting lip 18 can be folded over so that its adhesive seals onto the outside of wall 13, thus forming a second seal on top of the previous seal.

If an attempt is made to open the bag after sealing the polyethylene will distort and/or tear and the seal cannot be opened cleanly and then resealed.

Thus bags can only be opened at the end of their use and cannot be tampered with and resealed in the meantime.

Other security precautions may have been applied to the bags. Thus during manufacture of the bag, micro-security printing may be applied adjacent the seal lines 15, 16 suitably on the skirts 17 and at the mouth of the bag so that any illicit opening and resealing of the bag will be immedi ately discernible because of removal and/or distortion of the printed skirts. Alternatively, "codedseals" may be applied at 15 and 16, i.e. wording or other coding is embossed in the film by the sealing rollers. The double seal at the mouth of the bag makes it impossible to open the bag without tearing and distorting the seals in such a way that tampering will be obvious. As a further security precaution, the lip 18 and adjacent portion of wall 12 up to line 19 plus that portion of wall 13 which will seal against wall 12 in use, are provided with micro-perforations to weaken the polyethylene.

This increases the destruction of the polyethylene if any attempt is made to tamper with the sealed bag.

The bags may conveniently be manufactured by the procedure described in our Patent Specification No. 2009707B where two strings of bags are made from a single extruded tube of plastics.

The adhesive is suitably applied already held to the peelable strip so that adhesive and strip are applied in a single operation.

In the form of bag shown in Figure 3, there is no lip 18 and the adhesive and peelable strip 20 on wall 12 are entirely overlaid by wall 13. After insertion of the bank notes the bag is simply sealed by squeezing together the two walls. To avoid any difficulty in registering the open ends of the bag when it is full of bank notes, in the form of bag shown in Figure 4 the adhesive and peelable strip are positioned on wall 12 somewhat spaced from the open end of the bag. Thus when the walls are squeezed together there is no danger of the adhesive portion being out of alignment with a portion of the opposite wall and not producing an effective seal.

It will be seen that the above described bags are very easy to use for the bank as no special equipment is needed to close the bags and they can be easily closed whenever and wherever necessary.

Claims (7)

1. A bag, intended in use to provide a tamperproof package, the bag being formed of overlying walls of synthetic plastics material and having an open end for insertion of goods to be packaged, at least one wall having at or adjacent the open end an adhesive portion temporarily protected by a strip of peelable material, at least part of the adhesive portion being overlaid by the opposite wall before the bag is used and the adhesive being selected so that, when the peelable strip is removed and the bag sealed by causing the adhesive to seal against the opposite bag wall, the package so formed cannot be opened along the seal without destruction or distortion of the synthetic plastics material.

2. A bag according to claim 1 wherein the adhesive portion on one wall extends beyond the opposite wall at the open end of the bag so that, when the peelable strip is removed, a second seal can be formed by folding over the extension onto the outside of the opposite wall to give double seal security.

3. A bag according to claim 1 or 2 wherein the bag has a length greater than its width with the two walls being formed from a single strip of plastics material folded in such a manner that one end of the bag is constituted by a fold of the strip and the other open end by the ends of the strip, the walls being sealed together by seals adjacent their longer side edges.

4. A bag according to claim 3, wherein the wall seals are spaced from the side edges and the skirts so formed bear micro-security printing.

5. A bag according to any one of the preceding claims wherein micro-security printing is provided adjacent the open end of the bag, where in use a seal will be formed.

6. A bag according to any one of the preceding claims wherein micro-perforations are applied to the bag on or adjacent the ends of the walls which effect the seal.

7. A bag intended in use to provide a tamperproof package, substantially as shown in the accompanying drawings and described herein with reference thereto.