Note: Descriptions are shown in the official language in which they were submitted.
W092/0~085 2 0 9 1 7 7 0 PCT/CA91/00340
Closure for a Cont~i n~r
FIELD OF TB INVENTION
This invention relates to a closure for a
container, and more particularly, but not exclusively,
relates to a two-piece enclosure for a glass bottle.
Rl~c~rrt~uND OF THE INVENTION
At the present time, at least in Canada, most
milk and other dairy products are sold in disposable
cont~i ners, eg. cardboard cartons or plastic bags. In
some areas, reusable glass bottles are used, but this is
a relatively small part of the whole market. Nonetheless,
in view of the increasing environmental concerns regarding
disposable packaging, the use of the glass bottles for
milk and other dairy products is increasing rapidly,
currently, at an annual rate of approximately 25%.
A problem arises with providing a simple and
economical closure for glass milk bottles. A variety of
different closures are known. One type with which the
applicant is familiar and currently produces is formed
from a paper foil laminate. A cap is a disk form cut from
laminate and then crimped around the neck of a milk
bottle. It thus forms a top, circular, closure portion,
with a shirt portion depending downwardly. The skirt
portion is crimped against the neck of the bottle. In a
variant, a cardboard disk is mounted to the top of the
closure. The top of the closure is then dished down
inside the neck of the bottle, so that the cardboard disk
is within the neck of the bottle.
Whilst this type of closure is relatively simple
and economical, it suffers from a number of disadvantages.
First, it does not provide any true evidence of tampering
with the container. It is conceivable that someone could
remove the closure, and somehow tamper or interfere with
the contents of the bottle, and then replace the closure.
Further, whilst in normal use, the closure can be replaced
after it has been opened, it does not provide wholly
satisfactory resealing of the bottle by simply being
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placed on it.
It is desirable that a closure for a glass milk
bottle, and other containers, should meet two
requirements. First, it should provide clear tamper
evidence, of any tampering of the bottle or its contents,
which preferably should be readily externally visible.
This then enables a consumer in a store to immediately
ascertain whether the bottle has been tampered with or
not, without the necessity for removing any external cap
or cover member. Secondly, the closure should enable the
bottle or other container to be satisfactorily resealed,
so that where only part of the contents are used, it can
be resealed and retain the remaining contents in good
condition.
Further, for a two-part closure, i.e. one which
includes an inner seal effecting a primary closure of the
cont~iner and a secondary outer cap or closure, it is
desirable to have some means to prevent caps being
switched between different bottles or cont~iners. For
example, for dairy products, it is known for unscrupulous
consumers to switch caps between products of different
price, eg. 2% milk and cream, in order to be able to
purchase the more expensive product at a lower price.
There are a wide variety of conventional tamper-
evident closures on the market. These are generallyunsuitable for glass bottles. Many of these are in the
form of plastic-moulded caps. In one common design, a
screw cap is secured to a ring by a number of small,
radial spokes. The ring engages part of the bottle so
that when the cap is unscrewed the spokes shear, thereby
giving an indication that the container has been opened.
This cannot be used on glass milk bottles, since they do
not include a screw thread, and since the tolerances
obt~in~hle with glass would not permit the cover to always
securely engage the bottle.
Another design employs a collar connected to a
cap by an annular strip, which extends through slightly
W092/OS085 2 0 917 ~ O PCT/CA91/00~0
less than a full circle, to leave the cap secured to the
collar by a short connecting strip. The strip is provided
with tab, to enable it to be removed, thereby largely
detaching the cap from the collar. The cap can then be
hinged upwardly to open the bottle, whilst rer~i n i ng
attached to the collar at one edge. Yet another design is
a simple plastic cap with a pull ring. Such arrangements
again require fairly tight tolerances on the bottle neck,
and this is not readily or routinely achieved with a glass
milk bottle.
It is also desirable that any primary or inner
seal for the container or bottle should be readily
removable, and should be capable of simple and economic
manufac~ure and mounting on the container. It is well
known t. provide a foil closure seal to the neck of a
contAiner, although this is not routinely done with glass
bottles since it is difficult to obtain an adhesive that
provides a good seal to glass. Nany such closures are
provided with some sort of tab to facilitate removal of
the foil. Where an outer cap is provided, the tab is
usually folded over on top of the main body of the foil,
so as not to interfere with screw threads, etc. which
secure the cap to the bottle neck.
Patent No. 4,155,439 discusses in detail the
production of a foil closure with a folded pull tab. As
this patent shows, complex machinery is required to form
the closure and fit it to the container. A circular table
or platform is provided, in which the containers are
placed. The table is then rotated, to move each container
through numerous different stations. At each station, a
different operation is performed. The closure itself is
stamped fr~m a strip of foil, and then the tab has to be
folded UF ~n top of the main portion of the closure. This
requires a complex sequence or operation. To set up such
machinery for a particular production run is time
consuming and expensive.
It is should also be noted that additional
W092/05085 PCT/CA91/00~0
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problems are also encountered with such a technique.
Firstly, the presence of the inwardly folded tab can
affect the sealing by means of induction heating.
Induction heating relies upon the generation of currents
to heat the foil. The presence of the tab affects the
electrical properties locally, and can result in improper
sealing. As discussed in an article by Bill Zito in the
August, 1986 issue of Food and Drug Packaging, the current
tends to follow the actual periphery of the tab. Also,
the folded tab can stick to the inside of the cap, which
then requires a silicon liner or the like. The induction
sealing technique further relies upon the fact that the
foil closure is pressed against the neck of the container
by the cap. For the folded tab, there may not be even
pressure applied to the foil closure which again can
result in an imperfect sealing.
With such a folded tab, there is no external
evidence of any tampering with the container, so that
strictly a consumer needs to remove the screw cap or the
like to ascertain that the inner seal is intact. Further,
there is nothing to prevent a consumer switching caps
between containers or bottles.
As mentioned above, it is commonly known to
provide a foil closure with some sort of tab extending out
from the neck of the container, to facilitate removal of
the foil. Further, instead of folding the tab on top of
the main body of the seal, it is known to leave it
exten~ing down between the neck of the bottle and the cap.
U.S. patents 3,032,325 and 4,209,126 both show a tab which
is thus sandwiched between the side wall of the cap and a
bottle neck.
It has further been recognized that, where a
foil inner seal or the like is provided in combination
with a secondary, exterior cap, then to a casual
purchaser, there is no clear indication that the inner
seal is intact and has not been tampered with. Indeed, a
purchaser of a product may not discover that the seal is
W092/0508~ 2 ~ 91 7 7 0 PCT/CA91/00340
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broken until they come to open and use the product. Thus,
U.S. patents 4,576,297 and 4,579,240 show a cap bonded to
an inner seal in such a manner that removal of the cap
alone ruptures the seal. The cap itself is transparent or
translucent, so that a purchaser or first user can check
to see that the inner seal is intact. As soon as the cap
is removed, the bond between the cap and the inner seal at
least is ruptured, thereby providing an indication that
the cap at least has been removed or tampered with.
European published applications 109592 and
0111900 similarly provide an indication that a cap has
been removed or tampered with, so that a purchaser or user
can check the integrity of the primary seal, without
having to remove the cap. European published application
lS 109,592 further relies upon a colour change to provide
such an indication.
However, all these earlier patents rely on a
relatively complex combination between the cap and the
inner seal. Further, they do not provide any tab or the
like for removing the inner seal. Whilst the bond between
the cap and the inner seal may be ruptured, to provide the
necessary indication of cap removal or displacement, this
does not necessarily remove the inner seal. Accordingly,
the user is still left with the problem of detaching the
inner seal from the neck of the container.
Summary of the Present Invention
In accordance with the present invention, there
is provided a closure for a cont~inçr, the closure
comprising: an inner sealing member, which comprises a
membrane having a main portion for securing to the neck of
a container and a tab extending out from the main portion;
an outer cap, for enclosing the inner seal on the neck of
the contain~r, and including a top wall and a depending
wall for enclosing the neck of the container, with the tab
ext~n~ing down against an inner surface of the depending
wall; and adhesive means bonding the tab to the depending
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209177 6 -
wall, whereby the outer cap cannot be removed without
rupturing the adhesive means.
Preferably, the tab extends around the depending
wall and includes a second, end portion extending upwardly
against the depending side wall, with the adhesive bonding
that second, end portion to the cap.
For some configurations of bottle neck and cap,
it may be possible to effectively remove the outer cap by
a hinging action about the tab, thereby not causing the
tab to be detached from the wall of the cap. In such a
case, it is preferred to provide two tabs, which
advantageously are generally diametrically located, with
both tabs secured to the outer wall of the cap. Then the
cap cannot be removed without detaching at least one of
the tabs.
Preferably, the adhesive means bonds the tab to
an exterior layer of the outer surface of the cap wall,
which has a first colour. The adhesive means is strong
enough to cause at least a portion of this exterior layer
to be detached from an underlying interior layer having a
second colour, contrasting with the first colour. This
then provides a clear colour indication of detachment of
the tab, since detachment of the tab detaches a portion of
that exterior layer to reveal at least a portion of the
underlying interior layer of different colour.
Brief Description of the Drawing Figures
For better underst~n~ing of the present
invention, and to show more clearly how it may be carried
into effect, reference will now be made, by way of
example, to the accompanying drawings, in which:
Figure l is a perspective view of a cap in
accordance with the present invention mounted on a neck of
a bottle;
Figure 2 is a perspective view, similar to
Figure l, showing detachment of the tab from the cap;
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Figure 3 is a perspective, exploded view,
showing removal of the cap from the inner seal and neck of
the contA;ner;
Figure 4 is a perspective view, similar to
Figure 3, showing detachment of the inner seal from the
bottle neck;
Figure 5 is a vertical sectional view through
the cap, inner seal and neck combination shown in Figure
l;
Figure 6 is a sectional view, similar to Figure
5 showing a cap and inner seal combination with two tabs;
and
Figures 7, 8 and 9 are perspective views similar
to Figure 1 of alternative embodiments of the invention.
Descriptions of the Preferred Embodiments
Referring to Figures 1 and 5, which show the cap
and inner seal completely intact, the neck of the bottle
is generally indicated by the reference 1. Bonded to this
neck 1 is a metal foil inner seal 2.
In known manner, the foil inner seal 2 has a
layer of hot melt adhesive, or any other sort of adhesive
4, on its underside. This layer of adhesive 4 bonds the
foil 2 to the neck 1.
Extending out to one side, the inner seal 2
includes a tab 6.
The cap 8 is formed from a thick paperboard in
two pieces. Thus it is formed from a circular portion 10
that forms a depending wall enclosing the neck 1, and a
top circular part 12 forming a top wall. The cap 8 is a
snug or tight fit on the neck 1.
The tab 6 has a first portion 7 extending down
between neck 1 and cap 8. The tab 6 then extends down
below the bottom of the depending wall 10 and is then
folded back upwards to form an upwardly extending exposed
tab portion 14.
~Oql'~1~
The foil inner seal 2 with the tab 6 is cut from
a foil sheet pre-coated with the adhesive 4, so that this
adhesive layer also extends along the underside of the tab
6, but it is not activated to cause it to bond to any
other element.
The uppermost part 16 of the upwardly extending
tab portion 14 may be folded back as indicated, to form a
gripping portion. Alternatively, this folded back portion
may be omitted. This folded uppermost part 16 could be
bonded together simply by the adhesive 4 on its facing
inner surfaces.
The depending wall 10 at least of the cap 8 has
an exterior paper layer 18, that is bonded to an interior
layer 20, as shown in Figure 2. The exterior paper layer
18 is provided with a first colour, which is contrasting
to the second colour of the interior layer 20, to provide
a clear indication of rupture or detachment of the tab 6
from the cap 8, as detailed below. For a plastic cap, the
main body could form the inner layer, with the outer layer
being a separate layer or finish applied to the cap.
It is not essential to provide the two layers
with different colours. Instead, they could be the same
colour, with detachment of part of the exterior layer
being shown by the tear line or fibre texture.
Adhesive portion 22 is provided, as a securing
means, bonding a lowermost part 17 of the tab portion 14
to the exterior paper layer 18, as shown in Figure 5. This
adhesive 22 is an approximately rectangular patch of
adhesive and has a bond strength-greater than that between
the interior and exterior layers 18 and 20. Further, since
the tab 6 is a metal foil, the adhesive portion 22 will
preferentially cause the layers 18, 20 to detach, when the
tab 6 is pulled away from the depending wall 10.
In use, the cap 8 is provided with the inner
seal 2 already located in position against its top wall
12. The tab 6 is provided folded around the depending wall
Q 92~ SU~5 rl I UTE SHEET
W092/05085 2 ~ ~1 7 7 0 PCT/CA91/00340
_ g _
10 and bonded by the adhesive at 22 to form a complete
closure 3.
A bottler or other installer of the closures 3
fills individual bottles or cont~iners, fits the cap
assembly or closure 3 to the neck 1 of the bottle or other
container, and then causes the adhesive 4 to bond the foil
inner seal to the neck 1.
Where, as is preferred, a hot melt adhesive 4
and a metal foil inner seal 2 are provided, then this is
achieved by induction heating, in known manner. The cap
assembly 3 is then installed as shown in Figure 5.
In this configuration, the cap 8 cannot be
detached, without rupturing the connection between the cap
8 and the tab 6. Accordingly, it should not be possible
for any unscrupulous person to in any way tamper with the
cap assembly 3 or the contents of the bottle or other
container.
Another advantage of the attachment between the
seal 2 and the cap 8 is that unscrupulous or dishonest
purchasers cannot switch caps 8 between different
containers. Thus, in the dairy industry it is anticipated
that certain such purchasers may switch caps between high
and low priced products, with the intention of purchasing
the higher valued product, for the price of the lower one.
To open the container, a user first grips the
doubled over uppermost gripping part 16 of the tab 6 and
pulls it downwards, shown in Figure 2. The adhesive
portion 22, as mentioned, then detaches a portion of the
exterior layer 18, thereby revealing a portion of the
interior layer 20, giving a clear indication that the seal
has been broken. This is indicated in Figure 2.
The cap 8 can then be removed, as shown in
Figure 3. The whole tab 6 can then be grasped and lifted
to remove the complete inner seal, as indicated in Figure
4.
Figure 4 also indicates, at 24, that part of the
adhesive layer 4 may remain on the lip 26 of the neck 1,
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the lip 26 being the actual surface to which the adhesive
bonds. Whether or not such an adhesive layer 24 re~i n~
will depend upon the characteristics of the adhesive layer
4 and its relative bond strengths to the inner seal 2 and
the lip 26.
After opening of the bottle or container, the
foil inner seal 2 can be discarded, and the cap 8 can be
refitted, to effect reclosure of the bottle or container
for a short period. For example, in the case of dairy
products, the bottle can be reclosed until the contents
have been entirely used.
For some configurations of cap 8 and neck 1, it
may be possible to detach the cap by hinging action,
without actually detaching the tab 6 from the cap 8. To
guard against this, as shown in Figure 6, two tabs 6, 9
can be provided. The tab 9 is essentially a mirror image
of the tab 6, provided diametrically opposite to the tab
6. Then, in order to remove the cap 8, it will be
necessary to detach at least one of the tabs 6, 9 thereby
giving a clear, external visual indication that the cap
has been detached and possibly the container tampered
with.
With regard to preferred materials, the
depending wall or circular portion 10 of the cap 8 is
formed by helically winding two or more papers of various
thicknesses. The other two plys would be approximately 15
point board, with the outer layer forming the interior
layer 20. It would then be covered by an outer ply of
thinner material, forming the exterior paper layer 18.
The top wall 12 is formed from 20 point paper
board.
The inner seal 2 is formed from an aluminum foil
having a thickness of 50 microns (2 thousandths of an
inch). Adhesive layer 4 is preferably a hot melt adhesive,
specially adapted for bonding to a glass surface, such as
a surlyn-based adhesive.
W092/05085 2 ~ ~1 7 7 0 PCT/CA91/00340
As an alternative, instead of the two-part cap
8, a unitary plastic, moulded cap could be provided.
It is possible for the tab to only extend down
between the bottle neck and the depending side wall of the
cap to be sufficiently transparent or translucent for the
tab to be visible through it. The tab would then be
bonded to an inner surface of the depending side wall of
the cap. This configuration would be visible through the
cap side wall, so again there would be externally visible
evidence of any tampering with the closure, i.e.
separation of the tab from the cap side wall would be
visible through the cap side wall.
Reference will now be made Figures 7, 8 and 9
and which show alternative embodiments of the present
invention. In these drawings, like parts are given the
same reference numerals as in the earlier embodiments.
Referring to Figure 7, to provide an enhanced
degree of security, the upwardly exten~ing tab portion 14
is additionally secured by a security strip 30. This
strip 30 is generally rectangular and includes lines 32
providing lines of weakness between ends of the security
strip 30 and a central portion thereof. The lines 32
could be perforations or lines _ut partially through the
strip 30.
The ends of the security strip 30 are bonded by
patches of adhesive (not shown) to the cap 8.
In use, when the user grasps the upwardly
extending tab portion 14 and pulls it away from cap 8,
this ruptures the lines 32. Preferably, the security
strip 30 has a surface colour which is different from the
colour of the main body of the strip 30, to provide a
clear visual indication of any such rupturing.
The central part of the strip 30 could either be
secured to the tab portion 14 by a patch of adhesivej or
it could be free.
Figure 8 shows an alternative embodiment having
a security strip generally designated by the reference 34.
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Here, the security strip 34 does not have any lines 32,
and is bonded by adhesive both to the upwardly extending
tab portion 14, and at either end to the wall of the cap
8. Again, the adhesive portions are not shown as such.
When the tab portion 14 is pulled away from cap 8, the
security portion 34 is detached with it. Consequently,
the ends of the security portion 34 separate from the cap
8. Again, it is preferred that for the adhesive at the
ends of the security strip 34 to remove surface portions
of the cap wall having a different colour from the
underlining material of the cap. This again provides a
clear visual indication of any tampering with the
contAiner.
Figure 9 shows yet another embodiment of
security strip, here denoted by reference 36. This
security strip 36 is a continuous strip or ring around the
periphery of the cap 8. It need not be attached to all
points but it is attached at a sufficient number of
points, by adhesive patches, that it cannot be removed to
enable the upwardly exten~ing tab portion 14 to be
detached. Thus, strip 36 could be attached at, for
example, four equally spaced portions around the periphery
of the cap 8, with or without being attached to the
upwardly extending tab portion 14.
Again, Figure 9 also shows an extended tab
portion 14, indicated at 14a. It is preferable for the
tab to present a portion above any security strip that is
suitably sized for gripping between the thumb and
forefinger.
When the exten~ tab portion 14a is gripped and
pulled downwa~ds, it will rupture the security strip 36,
again providing an indication of any tampering. The strip
36 should be a contrasting colour to the wall of the cap
8, to provide a clear visual indication of any such
tampering.
In the embodiments of Figures 8 and 9, as for
the Figure 7 embodiment, the adhesive portion 22 could be
W092/OS085 PCT/CA91/00~0
2~91770
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omitted or included as desired. It is preferred for
security strip to be secured by adhesive to the upwardly
extending tab portion 14, to prevent the portion 14 from
being slid from underneath the security strip. This might
enable someone to tamper with the container or contents,
reclose it and slide the tab portion 14 back under the
security strip.
A variety of materials could be used for the
security strip 30, 34 and 36. They could be formed from
paper or like materials of alternatively formed from a
plastic film. In the latter case, the film could be at
least partially transparent.
