GB2202823A

GB2202823A - Improvements in or relating to containers

Info

Publication number: GB2202823A
Application number: GB08706983A
Authority: GB
Inventors: Milton Thomas Morton
Original assignee: MARDON WRAPPINGS Ltd
Current assignee: MARDON WRAPPINGS Ltd
Priority date: 1987-03-24
Filing date: 1987-03-24
Publication date: 1988-10-05
Anticipated expiration: 2007-03-24
Also published as: GB8706983D0; GB2202823B

Abstract

A tamper evident container e.g. bag, is formed of sheet material and has an opening (9) in the sheet material to provide access to the interior of the container. Film material (20) is attached to the sheet material adjacent to the opening (9) and a flap portion (4) of the container is adhered (8) to the film material (20) to close the opening (9). The tear strength of the film material (20) is less than the bond strength of the adhesive (8) so that attempts to pull apart the flap portion (4) and the film material (20) cause tearing of the film material (20). The adhesive (8) may be provided on the flap portion and/ or on the film material (20), and covered by a release masking tape (7). The film material (20) may be micro perforated and printed with a solvent soluble dye, or said dye may be provided on the bag wall beneath the film material (20), so that if the adhesive (8) is treated with a solvent staining will become visible. <IMAGE>

Description

IìrJ2vOf"'~'iTS IN OR ?-ftTATINC TO CO's1AI;.RS This invention relates to containers and is concerned with containers which exhibit a visible indication if an attempt has been made to gain access to the contents of the container.

It is known for banking establishments and the like to use containers for transmitting specified sums of money from one department to another The system operated by the establishment is ordinarily such that it can readily ascertain if such a container is stolen in transit. Ordinarily, however it is not readily possible to ascertain whether the container has been opened in transit and then resealed after some of the money has been removed With a view to overcoming this problem, tamper evident containers have been devised wherein any attempt to gain access to the interior of the container is visibly apparent.

It is also known to use containers for storing personal belongings in prison establishments and the like in such a manner that it is visibly apparent if any attempt has been made to open the container and steal some or all of the belongings It is an object of the present invention to provide a container which provides a novel indication of attempted opening.

According to the present invention there is provided a container formed of sheet material and having an opening to enable access to be gained to the interior of the container, the container including a flap portion~, film material attached to the sheet material adjacent the opening and adhesive for adhering the flap portion to said film material to close the opening wherein the tear strength of the film material is less than the bond strength of the adhesive.

Any attempt to gain access to the interior of the closed @@@@@@@@@@ by lifting up the flap portion will result in rf.Jfle o, the film material and this makes it visibly apparent that said attempt has been made.

The film material may be formed of any suitable plastics material and may be attached to the sheet material by means of an adhesive. Preferably, however, the film material is heat sealed to the sheet material.

Any suitable adhesive, such as a hot melt adhesive or a solvent soluble adhesive may be used.

The adhesive may be coated onto a masking tape which has been treated with a release agent and which is adhered to said flap portion or to said film material by the adhesive In this case, in use the masking tape is removed to expose the adhesive and the flap portion and the film material are then superposed so that they become adhered together by means of the adhesive. In accordance with a particularly preferred embodiment, adhesive may be provided on both the flap portion and the film material in order to improve the adhesive bond.

A solvent soluble dye may be located between the film material and the sheet material so that, if any attempt is made to treat the adhesive bonding the flap portion to the film material with a solvent to gain access to the container, staining will occur and provide a further indication of-attempted entry. In order to facilitate this, the film portion may be micro perforated A similar effect can be obtained-by printing the film portion with solvent soluble dye.

The container may be formed by superimposing portions of the sheet material and joining the same around their edges If desired security printing or coded seals may be provided at the edges to make it evident if access to the contai1ler has boon g --d by citing the edges and subsequently resealing 4-'iem.

Similarly, security printing may be provided in the vicinity of the opening of the container.

Any suitable sheet material may be used to form the container such as paper cardboard, thermoplastic plastics film, and combinations of the same.

The container is useful in any fields where tamper evident containers are needed such as in banking establishments, prison establishments1 retailing hospitals, examining boards, forensic laboratories, government departments, and the like.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying drawings in which: Figure 1 is a plan view of an open container in accordance with the present invention, Figure 2 is a section through the container of Figure 1 along the line II-II but with the container in its closed configuration and the thickness dimensions greatly exaggerated, and Figures 3 to 7 show in diagrammatic form the steps involved in producing the container of Figures 1 and 2.

Referring to Figures 1 to 7, the container is in the form-of a bag formed of flexible thermoplasticplastics material such as polyethylene. A solvent soluble dye--is applied to a longitudinally extending region of a continuous length of the thermoplastic plastics material.

A strip of thin polyethylene film 20 provided with small perforations is then applied to the dyed region and heat sealed thereto by heat seals 21 The 3). The tear strength of t?'i"3 film 20 is less than the bond strength of the subse'ucntly applied adhesive 8. The bag is produced by folding longitudinally the continuous length of thermoplastic plastics material (after it has been optionally printed as appropriate), into a J-form wherein it includes a first portion 1 folded longitudinally at 2 so as to be superposed on part of a second portion 3 so as to leave a flap portion 4 exposed (Fig. 3). ,The first portion 1 is heat sealed to the second portion 3 by a longitudinally extending heat seal denoted by reference numeral 5 (Fig. 4).Thereafter, a longitudinally extending region 6 of the-flap portion 4. which region is generally parallel to the heat seal 5, is subjected to a corona discharge to improve its adhesion characteristics provided in that region (Fig. 5).

A masking tape 7 formed of a base film of thermoplastic plastics material and coated with a silicone resin release agent is then coated with a hot melt adhesive 8. The adhesive may be synthetic rubber based pressure sensitive hot melt adhesive of the type known under the designation-089-2505 and marketed by National Adhesives and Resins Limited. This is a pale beige odourless material of 1008 solids content.

It has a viscosity (Brookfield Thermosel) at 120 C of about 63000 cps and its viscosity at 200 C is about 3500 cps. The adhesive 8 may be applied at a temperature-of -from about 150 C-to 180 C to the masking tape 7 by meansof, for example; a hot melt slot coater.

The thus coated masking tape is then adhered to the region 6 of the flap portion 4 which had been treated by the corona discharge so that it adheres thereto by means of the adhesive layer 8 (Fig. 6).

Thereafter, the first portion 1 is provided with a lollf3itudinally extending cut 9 5 een the film 20 and the heat seal 5 and this cut 9 serves as the opening to the container proper. Also, a further longitudinal line of perforations 10 is provided in the flap portion 4 equidistant between the heat seal 5 and the masking tape 7 (Fig. 7).

The continuous length of film material is then cut transversely using a double heat sealing device comprising two pairs -heat sealing jaws between which is located a cutting blade so that the material is cut into adjacent transverse portions wherein-each of the transverse portions has heat sealed edges 12 Each of these transverse portions constitutes a bag and if desired, each transverse portion may be given a sequential number for security purposes.

In use, articles are inserted into the interior 11 of the bag through the cut 9. Then, when it is desired to seal the bag, the masking tape 7 is removed from the adhesive layer 8 and the flap portion 4 is folded over~the first portion 1 (perforations 10 constituting the fold line) so that the layer 8 is superposed over the film 20 and the cut 9 as shown in Figure 2 and adheres portion 1 and film 20 together.

The interior 11 of the bag is thus completely sealed.

-- In the event that any unauthorised person-attempts to gain access to the interior 11 by applying a solvent for the adhesive-8,.-the solvent-will pass through the:perforations--i-n-the-film-20 and cause visible sta-ining between-the-first portion of the sheet material and the film 20. Moreover, if an attempt is made to gain access by pulling the flap portion 4 and portion 1 apart, the film 20 will tend to tear and provide a visible indication of attempted entry If desired, the inner marginal area of the bag adjacent to heat seals 12 may be provided with security printing i.e. printed characters very close to the seals 12 to that any attempt to gain access to the interior 11 by cutting off the seals 12 and subsequently resealing them will be immediately apparent.

Claims

Claims:

1. A container formed of sheet material and having an opening to enable access to be gained to the interior of the container, the container including a flap portion, film material attached to the sheet material adjacent the opening and adhesive for adhering the flap portion to said film material to close the opening wherein the tear strength of the film material is less than the bond strength of the adhesive.

2. A container as claimed in claim 1 wherein the film material is attached to the sheet material by means of an adhesive.

3. A container as claimed in claim 1 wherein the film material is heat sealed to the sheet material.

4. A container as claimed in claim 1, 2 or 3 wherein the adhesive for adhering the flap portion to said film material is a hot melt adhesive.

5. A container as claimed in claim 1, 2 or 3 wherein the adhesive for adhering the flap portion to said film material is a solvent soluble adhesive.

6. A container as claimed in any one of the preceding claims wherein the adhesive is coated onto a masking tape which has been treated with a release agent and which is adhered to said flap portion or to said film material by the adhesive.

7. A container as claimed in any one of the preceding claims wherein the adhesive for adhering the flap portion to said film material is provided on both the flap portion and the film material.

8. A container as claimed in any preceding claim wherein a solvent soluble dye is located between the film material and the sheet material.

9. A container as claimed in claim 8 wherein the film material is perforated in the vicinity of the dye.

10. A container as claimed in any one of claims 1 to 7 wherein the film material is printed with solvent soluble dye.

11. A container as claimed in any preceding claim which is formed by superimposing portions of the sheet material and joining the same around their edges.

12. A container as claimed in any preceding claim wherein the edges of the container are provided with security printing or coded seals.

13. A container substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.