Note: Descriptions are shown in the official language in which they were submitted.
329~76
TAMPER EVIDENT ENVELOPE CLOSURE SYSTEM
FIELI~ OF THE INVENTION
This invention pertains to security envelopes and more
~ particularly to such envelopes that ara desi~ned to reveal
; 5 attempts to open the same and to reveal that the same have been
opened and resealed.
BACKGROUND OF THE INVENTION
Security envelopes have been been manuFactured from plastic
polymer ~ilms with special closure devices intended to reveal
tamper~ng. Sensitive in~ormation, whether stock sacurities,
money or whatever, are commonly shipped by courier or special
messenger in such envelopes. Those envelopes are commo~ly sealcd
by a strip of hot melt adhesive that has been applied along with
a release liner to one edge o~ the envelope opening during their
manufacture. To seal such an envelope, the release ltner ts
pulled away and the envelope ~lap folded down 1nto contact with
the exposed strip of tacky hot melt adhesive. Because the hot
melt adhesive remains tacky under normal environmental
conditions, and because the polymer packaging film is quits
flextble and easily distorted, it had been thought that any
tampering would be sasily self-evident. As an added precaution,
special devices were added, such as special printed desi~ns
applied to ths closure portion of the envelope that would
visually reveal stretching or distortion if the adhesive seal
were tampered with. Other tamper-revealing devlces have been
employed also. The essential element, however, has been tha use
of a hot melt adhesive tape strip in combinatlon with a flexible
plastic polymer film envelope because of the ease with which suGh
~; envalopes cowld be manufactured and because of the ease with
~hich such envelopes could be firmly sealed.
~ It has come as quite a shock to the envelope manuf~cturers
;~ and their customers, therefore, to di~.cover that clever thieves
and tamperers have discovered relative easy methods to opan these
~ hot melt adhesive sealed envelopes and reseal them wtthout
':
~'7
"
.' . .
' . ~ : ' .
~329176
`:
detectlon. A common technique ls to freeze the sealed envelope
adheslve strlp, such as by applylng dry ice or spraying wlth Freon
from a spray can. By freezing the adheslve strip, the envelope
closure flap can be carefully prled up away from the frozen
adhesive; the adheslve in effect looses lt~ grlp on the smooth
~, ~
~ fllm of the envelope. Careful attentlon to thls detall will leave
,,
; the frozen adheslve strlp lntact. To reseal the envelope the
adheslve strlp ls merely warmed to room temperature, at whlch
polnt lt becomes tacky agaln, and the closure flap is slmply
reapplled to the adhesive strlp. Other technlques have also been
used that result ln ~eparatlon of the adhesIve from the cover flap
~; ln an undetected way. Thls revelatlon resulted ln the bottom
dropplng out of the market for such envelopes.
. ~,
SUMMARY OF THE INVENTION
.
A prlmary ob~ect of the present lnventlon ls to provlde
.
~:;
a tamper evldent envelope wlth a closure system that cannot be
~- breached without the breach becomlng apparent. A further ob~ect
- ls to provlde such a closure system that lncludes a mechanlcal, or
structural, component that would reveal tamperlng, as opposed to
prlntlng applled to the envelope fll~.
The invention provldes an envelope comprlsing front and
rear panels sealed about thelr slde and bottom edges to form an
open-topped configuratlon; an appendage secured to one of sald
panels at a level below the opening into the envelope opening and
.;
extending across the panel, ~ald appendage having a wldth that is
~ubstantlally equal to the dlstance between the opposing side
.,
~ edges of the envelope and having a length sufficient for the
,.,
"~
" ,.
.~ ,. .. ..
, . ,
;-, .
.. . .
: ' ;
` 132~176
2a
appendage to functlon as a closure flap that can be folded over
the envelope and æecured to the other of sald panels at a level
below the envelope opening; and a band of adhesive adhered to and
extendlng across sald appendage at a mld-reglon thereof whereby,
when sald appendage ls folded over and across sald envelope
openlng ln a closure relatlonship thereto, said adhesive band wlll
contact both panels ad~acent said openlng and extend across said
. . .
envelope openlng whereby the folding of sai.d appendage ln a
closure relationshlp wlll result ln adheslve materlal adhered to
,.
both panels ad~acent the opening and adhered to ltself across the
envelope opening as well as to ~ald appendage.
The lnventlon al80 provldes a process of manufacturlng a
tamper evldent envelope comprlsing the steps of providlng a stock
,;.
of envelope panel materlal, provlding a stock of closure flap
materlal, formlng the envelope panel materlal lnto ~uxtaposed
,~
envelope panels wlth a closed end bottom and an Gpen top, applylng
a band of adheslve materlal lengthwlse along ~ald flap materlal,
r,,
~ securing the flap materlal to one of sald panels ad~acent the open
,.'A,, top at a location whereby the adheslve band extends from one panel
1 20 outward and has a sufflclent width to be capable of belng folded
., .
acrogs the open top and secured to the opposlte panel, and
severlng the comblned flap and envelope stock to provide dlscrete
open top bags, whereln the severed closure flap has a length
,..
~`; substantlally equal to the width of the envelope.
..~.
Y~ Durlng the manufacturln~ process, the opposed sldes of
~ the envelope are ~uxtaposed ~uch that the edges that define the
......
~, envelope openlng are even wlth one another. A cover ~lap ls
~ .
'
''', ' ' ~ '~ ' ~ `
. ~: ; . .
. . .
:' ~ ~ ., . -
-` ~329176
2b
secured to one slde of the envelope at a locatlon lnward of the
openlng (l.e. toward the closed ~nd). During the manufacturlng
process, a band of hot melt adheslve i5 applled to the lnner
surface of the cover flap at a location whlch will overlap the
envelope openlng when the cover flap is folded lnto seallng
engagement with the envelope. The adhesive band is covered with a
releare tape rtrlp whlch wlll be removed when the
:,
, .
~ B
, . . .
, ~
.~ . .
.. . .
~. , .
`` ~ 32917~
envslope ie to be sealed. When the release tape is removed, and
the cover flap applied in envelope-seallng engagement, the
adhesive band will be so positioned that adhesive will be pre~ent
on opposite sides of the envelope body, adjacent the opening, and
across the envelope opening itself. In cros~-section, tha
~ adhesive band, as applied to tha envelope opening, will appear
- channal-shaped. Consequently, ths adhesive will bond to itself,
- across the top of the envelope opening, as well as bond to the
envelope body adjacent to the envelope opening. Consequently,
the cover flap seal will comprise a channel-shaped band of
adhesive sealing the opening in adhesive-to-adhesive contact and
adhesive-to-film contact on both sides of the envelope opening.
Any attempt to tamper with this closure system, such as by
atte~pt~ing to separate the cover flap film from the adhesive band
or by separating the envelope body ~rom the adhesive band, will
not be disguiseable. Wh1le it might be possible to separate the
film-adhesive bonding contact on oither side of the envelope
opening, it will not be possible to separate the adhasive-to-
adhesive bonding contact across ths opening itself wtthout
rupturing the adhesive band. Thus1 any tampering will be self-
evidant by examining the closure.
RIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of an envelope in
`~ accordance with one poss1ble embodimant of the present invention;
Figure ~ ts a diagrammatic view of the envelope flap in open
position in accordance with one possible embodiment o~ the
present invention; and
~` Figure 3 i~ a diagramAtic view of the envelope ~lap in
closed position illustrating the channel-shaped con~uration of
the sealed adhesivs band; and
Figure 4 is a diagramat1c view of the envelope flap torn
away from its closure position with the channël-~hapad adhesive
band remaining in its sealed condition across the envelope
openirl8-
~,,
~ 35 DETAILED DESCRIPTION OF THE INVENTION
,;,
,,
. .
... .
'
1329~7t~
Attempts to tampor with security envelopes are becomingincreasingly sophisticated. The tools of a would be tamperer can
include the use of dry ice, Freon from a spray can, a knife, a
chem1cal such as a solvent or corrosive agent or heat. The
disadvantayes with a number of security bags is that the above-
mentioned methods can be used without giving evidence of
tampering. Dry ice or Freon causes the adhesive to lose its
adhesive strength, thus the envelope can be easily opened and the
adhesive warmed to seal the envelope again, knives can cut the
adhesive, again giving no evidence of tampering. Likewise the
sof~ening o~ the adhasive through the use of solvents, corrosive
agents or heat can be done in a manner such that the bag can be
opaned and resealed after evaporat;on of the solvent or cooling
of the adhesive.
It is an obJect of the present invention to provide a
tamper-evident security envelope which addresses the above
problems. Further objects and advantages will become apparent in
the following description which is given by way of example.
According to ons aspect of the present invention there is
provided an envelope comprising a front panel and a rear panel,
an appendage in the form o~ a closur~ ~lap secured to one side of
the envelope. The edges o~ the front and rear panels alcng one
end, the upper end as depicted in Figure 1, are even with one
another and define the opening into the envelope. A band of
adhesive is applied to the envelope flap at a position such that
the adhesive band will extend across the envelope oepning when
the flap is placed in a closure position. The bag is preferably
manufactured from any one of a number of plastics film, such as
high density polyethylene and may be manufactured frem a laminate
or co-extrusion having inner layers of plastics and an outer
~. layer of mica-filled or impregnated high density polyethylene.
`~ Essentially, the envelope is secured by the adherence of the
adhesive across ths envelope opening. The band of adhesive, when
the ~lap is closed9 is doubled back onto itself across the
envelope opening and a~heres to itself as well as adhering to the
,, .
. .
. .
:`
':
; ~ , .~,
.
.
,
132917B
side panels adjacent the opening. To enter the envelope through
its opening, the sealed adhasive channet must be tcrn away from
the opentng, thus making a forced entry obvious through the
distortion or tearing of the adhesive closure.
It is envisaged that the adhesive may bc si~uated on a clear
flap at the opening of the envelope~ the flap acting as a means
- of holding, regtstering and protecting the adhesive. If the
adhesive closure ts breached, as by attempting to freeze it and
pry it away from the envelope oepning, and then resealed, the
broken or tern adhasive channel will be evident through-the clear
flap. A preferred adhesive is of the pressure-sensitive hot melt
type which is applied to the flap at appropriate locattons in
liquid form at elevated temperatures and which becomes tacky, and
hence self-adhesive, at room temperatures. Suitable such
adhesives include the ethylene copolymer based famtly of hot melt
adhesives. If dry ice or Freon is applied to the adhesive, the
adhesive would solidify and lose most of tts strength. The flap
can then easily be peeled off the envelope thus exposing the hot
melt adhesive. However, envelope integrity is maintalned as the
-~ 20 band of adhesiva is fused to itself across the top of the
oepntng. In this frozen state tho britkle adhesive can ba easily
shattered and the envelope entered, but such entry would be
obvious from the appearance of the adhesive channel.
Attempts to enter the bag by cutting though the adhesive
25 would be difficult as it is envisaged that the adhesive may ``
extend to the edges of the panels thus giving nothing to grasp.
With reference to the drawings there is provided an
envelope, generally indicatad by arrow 1 comprising a front panel
~-~` 2 and a rear panel 3. The envelope closure flap generally
indicated by arrow 8 comprises clear polyethylane and may be
attached to the bag via a 1mm strip of hot melt adhesive or heat
sealed to the rear panel 3 as shown at 9, along the inner end of
~`~ the flap 8. Adhesive band 10, of hot melt adhesive, may be
secured as shown tn Fi~ure 1 onto the flap ~ and axtend to the
rl 35 edge ther~of. When the flap is attached as in Figure 1 the band
.
..
.. . .. ...
~;,
'
~ , . . . ..
,
^ ~3291~6
is wide enough to extend from one panel, across the envelope
opening to the other panel. The band 10 is approximately 30mm
wide and consists of a contiguous layer of hot melt adhesive
havin~ a thickness of about 1mm.
To protecit the hot melt pressure-sensitive band 10, a
backing strip of release paper would be applied to cover the
band during the manufacturing process. To use the envelope, the
operator would insert the appropriate material into the
envelope, remove the cover or backing strip to expose the
adhasive band 10 on the flap 8, and fold the flap over the
opening of the bag and seal the ~lap to both panels 2 a~d 3.
Because the band ie wide enou~h to extend across the openlng,
sealing the envelope as described causes the adhesive from e~ich
from separate locations on the single band to contact one
another at the envelope opening. Consequently, the adhesive in
the band adheres to both the adjacent panel 2 or 3 and to
itself.
An additional strip or strips 11 of hot rnelt adhesive may be
applied to the outer edge portion of flap 8 so that the free end
of the flap may be secured to the snvelope front panel 2 when the
flap is sealed to close the envalope. The additional adhesive
strip or strips would be protected with a covering of release
;.j paper, also, which would be removed when the envelope was to be
~;' sealed. Actually, the same release paper strip usad to protect
the adhesive closure band 10 could be extend to cover the strips
11 .
Any attempt to braach the bag's opening and then reseal the
i bag will become apparent because the adhesive channel will have
been torn and distorted. Even freaezing the hot melt adhesive of
the band 10 will not prevent damage to the adhesiive strip. As
an additional security feature, the closure flap 8 is perforated
cross~wise at 12 near the outer edge of the adhesive band lO.
,i~, This perforated line 12 provides a mechainically-weakened line
~` that would rupture first if access to the envelope's contents
were attempted by tearing or liflng the outer edge of the closure
. ~
.,
.
''.'~'
.
". , ,
. ~ . . ..
.,, ~ :,, ,
~ ~'' '' ' '': -
,'`,''~ . .
1329~7~
strip 8 beyond that required to clear the outer sealing strips
11. The perforated line ~s pra~erably provlded as a series of
short, narrow, longitudinal cuts through the closure strip
material. During the manufacturing process, closure strip stock
5 would be perforated, as by running it acros~ a perforating whsel,
to provide the perforated line 12. Providing the resultin~ cuts
would not entail the removal of any material so that the adges of
the material at the edges of the cuts would abut. Then the
adhesive bands tO and 11 would be applied to the face of the
10 strip 8 in the locations shown. The band 10 would be applied to
the closure strip 8 such that the outer edge of the band would
extend beyond the perforated line 12. Consequently, if an
attempt were made to gain access to a sealed envolope by lifting
the free outer edge of the strip 8, the strip 8 would tear along
15 the weakened, perforated line 12, thereby evidencing the attempt
to open. A strip of release paper would be applied to the face
; of the closure strip stock, leaving the envelope jo1nder adhesive
strip 9 exposed. The closure strip stock would then be applied
to envelope stock in a continuous process with the adhssive band
20 9 being rollsd onto the envelope stock to adher the closure strip
b stock to the envelope stock. The combined stock then would be
severed into discreke bags, or completed envelope~ each with its
own discrete attached closure flap, to complete the manufacturing
process. During the manufacturing process, sheet envelope stock
^~ 25 would be folded back on itsel~ to provide the envelopo panels 2
and 3, prior to the application of the closure strip stock.
Then, during the severance of the combined stock in~o discrete
bags, or just prior thereto, tha ~ide edges of the overlapped
envelope stock would be heat-sealed together to form the three-
; 30 sided, open-topped bags illustrated in the Figures upon
completion of the severing step.
- As a further measure, a s~milar perforated line could by
provided near the inner edge of the band 10, so that the band
~ inner edge would axtend beyond this additional perforated line~
s 35 As in the case of the function of per~orated line 12, this
~`
.
:,.
,~ , .... .
:
- ,
132~17~
- additional parforated line, located underneath but near the inner
edge of band 10, would be torn by the lifting of the inner edge
of the closuro strip for the purpose of opening the envelope.
While the preferred embodiment of the invention has been
described herein, variations in the design may be made. The
scope of the invention, therefore, is only to be limited by the
claims appended herato.
The embodimants of the invention in which an exclusive
property is claimod are defined as follows:
1 0
:'.
~ 15
. .
.. ... .
~.,.
~ .
'
,,'.
,.~ .
~',.
~,.
. . .
~: 30
~,
,,.,~,
., ,
.. 35
i:
,~i
.,:.
.
' ' . . .
,
