NZ239741A - Closure system for plastic bags; closed interlocking edge profiles give visual tamper indication - Google Patents

Description

2 4 P.F.5 Code 1050 Fee $260 NEW ZEALAND PATENTS ACT 1953 No. 239741/241336 Priority Date: 10 September 1991 and 17 January 1992 COMPLETE SPECIFICATION IMPROVEMENTS IN OR RELATING TO PACKAGING WE MINIGRIP FLEXIBLE PACKAGING LIMITED of 6 Ron Driver Place, East Tamaki, Auckland, New Zealand, a New Zealand company, do hereby declare the invention for which WE pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statements 1- \ 10SEPws$ 23974 241336 This invention relates to security packs and more particularly to pilfer evident receptacles such as envelopes, packs and bags.

Pilfer evident receptacles such as envelopes, packs and bags are often utilised in the transportation of securities be they documents, money and/or other valuables. Known security receptacles are generally either in the form of rigid containers or flexible bags, 10 pouches or envelopes. The latter are often manufactured from plastics film material and include an adhesive strip which must be fractured to open the bag or envelope. Experience has shown that these can be tampered with by, for example, chemically altering the structure of the 15 adhesive by lowering its temperature, such action releasing the bond provided thereby. A further disadvantage with such devices is one of cost, in that, opening requires damaging the receptacle to the ext'eniw'^V that further use even as a non-pilfer evident receptacle j ' is impractical. =\ 2 'l .. , ^ o ,.4 • f- t V V •* ;A first object of this invention is to provide a pilfer evident closure suitable for incorporation in or attachment to bags, envelopes or similar receptacles, 25 adapted to be resealable by way of engageable closure elements, and manufactured from plastics film enabling ;3 ;its utilisation for security purposes. ;In forming receptacles in the nature of plastic bags or envelopes incorporating engageable closure elements 5 manufactured by blowing plastics film typically the receptacles are fabricated by forming transverse seals, which become the sides of the bags, and severing the parent film adjacent those seals to form individual bags. The engageable elements may be either integrally formed 10 with the bag material or moulded separately and subsequently affixed to the film. It is considered desirable, if not essential, that when severing takes place that the engageable elements be engaged with one another as otherwise following severing the engageable 15 elements may be mis-aligned and may not function correctly. It follows that when manufacturing pilfer evident receptacles utilising engageable but irreversible interlocking elements such an approach is not suitable and a further object of this invention is to overcome ;} ;20 this problem. ;Yet a further object of this invention is to provide a pilfer evident receptacle generally in the nature of an envelope or pouch manufactured from plastics film which 25 following use as a pilfer evident receptacle will still be suitable for use as a conventional recloseable bag. ;# 23 9 7 4 1' /2k 1 5 3 ;According to a first aspect of this invention there is provided a pilfer evident receptacle characterised by an only opening thereto being sealably closeable by a pair of elongate irreversible interlocking profiles one along 5 each side of the opening, at least one of the profiles being disposed adjacent to or incorporating a pilfer evident means the integrity of which is irreparably altered with either complete disengagement or part disengagement of the profiles from one another resulting 10 in a visually evident violation of the integrity of the interlocking. ;According to a second aspect of this invention there is provided a method of manufacturing pilfer evident 15 receptacles by transversely severing at intervals receptacle elements from a parent tube of blown plastics film integrally incorporating a pair of elongate engageable interlockable profiles extruded longitudinally with the film and longitudinally slitting the film to 20 form an opening to the receptacle characterised in that the film also includes a pair of irreversibly interlockable profiles disposed inwardly of and adjacently parallel to the engageable interlockable profiles. ;25 ;According to a third aspect of this invention there is ;1 L> FEB W ;provided a pilfer evident receptacles closure comprising a pair of elongate irreversible interlocking profiles adapted to be affixed one along each side of an only opening of a receptacle, either complete disengagement or part disengagement of the profiles from one another resulting in a visually evident violation on the integrity of the interlocking therebetween. ;In further describing the invention reference is made to the accompanying drawings (Fig 1 to Fig 4) being fragmented cross-sectional views of various preferred embodiments each figure including optional features. ;A pilfer evident receptacle 3 is preferably in the form of an envelope, pouch or similar device fabricated from plastics film material. In a simplest of forms a receptacle bag 3 of conventional shape is formed by blowing plastics film to have an opening 4 extending across the full width of an upper end thereof. Pilfer evident interlocking profiles 5 and 6 are provided one along each side of the bag opening 4 to provide pilfer evident sealing of the bag as described in more detail hereafter. In the forms depicted in Figs 1, 3 and 4 the profiles 5 and 6 are formed as integral components of the bag 3 however as an alternative, as depicted in Fic 2, they can be formed as separate elements which are r ;1 4 FEB 1994 ;. RECEIVED ;23 9 7 4 f / 24 13 ;subsequently attached to separately formed bag film. ;In a first form of the invention the structure and geometry of the male profile 5 and female profile 6 provides that an irreversible interlock is formed with engagement of the profiles together. Figs 1, 3 and 4 depict a structure where the profiles 5 and 6 are integrally moulded with the bag 3 material. Fig 2 depicts a structure where the profiles are separately moulded and subsequently affixed to the bag 3 material. The heads 9 of the male profiles 5 are "over-sized" relative to the engaging members 10 and become entrapped therein following entry. To disengage the profiles 5 and 6 and/or open an associated bag 3 fracturing of one or both of the profiles 5 or 6 and/or the bag 3 is necessary to obtain access to the interior of the bag 3. ;A first variation of the invention incorporates within one or both of the profiles 5 and 6 a frangible feature. For example a weakened or break line 11 may be formed at the base of the stem of the male profile 5. Thus with opening the weakened line 11 will tend to fracture before either the parent bag 3 or the profiles 5 or 6 fracture. ;This frangible opening provides the benefit of easier opening without impairing the pilfer evident requirements of the bag 3. ;r ;j H FED 1994 ;I HuCEiVED ;23 9 7 4 1 ;24 ;Referring to the variation depicted in Fig 3 a similar result can be achieved by providing a degree of incompatibility (as to be of limited strength) between, the materials of the profiles 5 and 6 and, the material of the bag 3. Thus the weakened zone is the limited bond between the profiles 5 and 6 and the bag 3 material such that delamination will tend to occur when opening is attempted. ;This weakening can also be provided in the bag 3 material. For example, as depicted, preferably the bag 3 includes a flap 17 extending beyond the profiles 5 and 6. A perforated line 13 can be included in the flap 17 adjacent the profiles 5 and 6. Efforts to open the profiles 5 and 6 by pulling on the flap 17 will cause fracture along the perforated line 13. ;In a further variation one or other of the profiles 5 or 6 and/or the adjacent material of the bag 3 can incorporate a colouring. With engagement of the profiles 5 and 6 an apparent change in colour can be created. For example the profile 5 can be coloured yellow and the profile 6 coloured blue. With engagement the two colours produce a third colour, in this case, green. This colour set or change is disturbed with attempted disengagement ;1 4 FEB 1994 ;. RECEIVED ;^ 9 74 11 /24 i of the profiles 5 or 6 to thus indicate possible tampering. ;In yet a further variation the material and/or extrusion characteristics of the profiles 5 and 6 may be altered to provide a similar result. For example, fillers or additives may be added to the material of one or both of the profiles 5 or 6 to increase the brittleness thereof. As a consequence the profiles 5 and 6 are more likely to fracture before disengagement is achieved. A similar result can be achieved by varying the extrusion characteristics to alter the elongation and tensile properties of one or both of the profiles 5 and 6. ;In a further variation a hot melt adhesive 12 can be provided between the limbs of the female profile 6. With engagement the male profile 5 contacts the adhesive 12 and additional irreversible interlocking is achieved. Preferably the adhesive 12 is laid while molten between the profiles 6 during production and has a high surface "tack" allowing an instant bond. ;Referring in particular to Fig 1 in an alternative embodiment a receptacle bag 3 is manufactured with one profile (as depicted the female profile 6) on the outside of the bag 3 film and one profile (as depicted the male— ;'23 9 74 1 /24 } 35 ;profile 5) on the inside of the bag 3 film during the blow moulding process. In moulding the closure elements 5 and 6 are disposed in radially spaced apart relationship about the periphery of the bag 3 film tube. ;5 Preferably in forming a bottom 14 to a bag 3 the bottom 14 is disposed further from the closure element 5 disposed on the inside of the bag 3 then the closure element 6 disposed on the outside of the bag 3. Thus a flap 20 or overlap is formed associated with the closure 10 element 5 on the inside of the bag 3. Closure of the bag 3 requires the flap 20 to be folded back on itself to bring the closure element 5 in engageable alignment with the closure element 6. ;15 Preferably the receptacle bags 3 of this invention include engageable clojure elements 7 and 8. The engageable elements 7 and 8 are included inwardly of the profiles 5 and 6 in substantially the same way as utilised for conventional non-pilfer evident receptacles. ;20 These engageable elements provide a dual function. First, the preferred form of opening bag 3 is by severing in the region indicated by arrow 15, that is between the disengageable elements 7, 8 and the irreversibly engaged elements 5, 6. Thus the bag 3 can subsequently be.. ;25 utilised as a conventional recloseable bag. Their second role is to maintain, during fabrication, alignment-of ..the ;TO;'.-.05 ;1 li FEB m ;. n::c~:ViED ;23 9 74 1^24 , ;irreversible engageable closure elements 5 and 6 to overcome the alignment problem referred to in the preamble of this specification. They may be formed as completely separate elements disposed, for example, in adjacent parallel relationship to the non-disengageable elements. ;A non-stick strip 16 of plastics film may be provided between the closure elements 5 and 6 to prevent inadvertent closure thereof. Where adhesive 12 is included the strip 16 also serves to protect contamination of the adhesive 12, the strip 16 preferably being formed from a silicon coated high density polyethylene. ;Referring to Fig 4, it will be appreciated by those skilled in the art that the profiles 5 and 6 can take a multitude of forms to achieve the irreversible interlock therebetween. Thus as a further example as depicted in Fig 4 the male profile 5 is bordered by lips 18 which, with engagement, straddle the profile 6 to further strengthen the interlock between the elements. ;In yet a further alternative embodiment (not depicted) the engageable elements 7 and 8 and the irreversible elements 5 and 6 may be combined. For example, a double ;1h FEB TO ;»23 9 7 4 f/to 1 ;headed (one equivalent to element 7 and one equivalent to element 5) projecting element can be appropriately disposed relative to a captivating element which acts as both elements 8 and 6. An outer or first insertable head of the projecting element may be disengageably retained in the captivating element enabling the closure to be "re-opened". An inner of the ends may be irreversibly engageable with the captivating element thus with further insertion of the projecting element an irreversible captivation is achieved. In addition and/or conversely the captivating element may be of two stages and a single headed projecting element provided. As previously mentioned part insertion provides a disengageable relationship whereas full insertion interlocks the elements permanently together at least to the extent of evidence of disengagement resulting with disengagement. ;~rH0 ;I *> F£3 m 2 J 97 41/^®^ \ ^ ' MAn j'a^4 "*:V'?i* >i \»"''.

Claims (12)

WHAT WE CLAIM IS:

1. A pilfer evident receptacle characterised by an only opening thereto being sealably closeable by a pair of elongate irreversibly interlockable profiles one along each side of the opening, either complete disengagement or part disengagement of the profiles from one another resulting in a visually evident violation of the integrity of the interlocking.

2. A pilfer evident receptacle as claimed in claim 1 including a pair of elongate re-engageable interlockable profiles inwardly of and adjacently parallel to the irreversibly interlockable profiles.

3. A pilfer evident receptacle as claimed in either claim 1 or claim 2 wherein a first of the irreversibly interlockable profiles is engageable between the arms of a second of the irreversibly interlockable profiles and an adhesive is provided between the arms of the second profile.

4. A pilfer evident receptacle as claimed in any one of the preceding claims wherein the receptacle includes flaps extending beyond the irreversibly interlockable profiles and a weakened line is provided in at least one of the flaps adjacent to the profile associated 13 23 24 therewith.

5. A pilfer evident receptacle as claimed in any one of the preceding claims wherein a removable strip is provided between the irreversibly interlockable profiles to prevent inadvertent closure thereof.

6. A pilfer evident receptacle as claimed in any one of the preceding claims wherein the irreversibly 10 interlockable profiles are moulded separately from the material of the receptacle and subsequently mounted thereto by bonding.

7. A pilfer evident receptacle as claimed in any one of 15 the preceding claims wherein the irreversibly interlockable profiles are moulded to have less strength^ than the associated receptacle such that they tend to fracture with attempted opening. > 2 / ^ 20 8. A pilfer evident receptacle as claimed in any one of the claims 1 to 6 inclusive wherein the mounting bond of one or both of the irreversibly interlockable profiles to a receptacle is of a limited strength whereby attempted opening of these profiles tends to fracture the bond. 25 10

. C't £ / J J- 14 * * * 239741/ ^ t a * § ' 2-41536? 5 ? W/1R ;gg4 r. <s % ^ <*• •-

9. A pilfer evident receptacle closure comprising a pair of elongate irreversibly interlockable profiles adapted for affixing along each side of an only opening of a receptacle, at least one of the profiles being disposed adjacent to or incorporating a pilfer evident means the integrity of which is irreparably altered with either complete disengagement or part disengagement of the profiles from one another resulting in a visually evident violation of the integrity of the interlocking.

10. A method of manufacturing pilfer evident receptacles by transversely severing at intervals receptacle elements from a parent tube of blown plastics film integrally incorporating a pair of elongate re-engageable 15 interlockable elements extruded longitudinally with the film and longitudinally slitting the film to form an opening to the receptacle characterised in that the film also includes a pair of irreversibly interlockable profiles disposed inwardly of and adjacently parallel to 20 the re-engageable interlockable elements.

11. A pilfer evident receptacle substantially as herein described with reference to the accompanying drawings. ^3 9 7 4 1'/ ^

12. A method of manufacturing pilfer evident receptacles substantially as herein described with reference to the accompanying drawings. MINIGRIP FLEXIBLE PACKAGING LIMITED 1 FEB m