Note: Descriptions are shown in the official language in which they were submitted.
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A CHILD RESISTANT CARTON PACKAGE
The invention relates to a child resistant carton package, the package
comprising an
outer sleeve of fiber-based material, an insert that can be slidingly drawn
out from
the sleeve, the insert carrying the packaged product, and a locking mechanism
between the sleeve and the insert, for preventing a child from drawing the
insert out
of the sleeve. Furthermore, the invention covers use of specific fiber-based
boards
for such carton packages.
Consumer packages for pharmaceutical or other products posing a risk for small
children must be designed so as to hinder an easy access by a child to the
contents
of the package. In box type packages consisting of a sleeve and a sliding
insert that
can be pulled out of the sleeve this has been achieved by locking mechanisms
dimensioned so as to require the hand of an average adult for their ready
operation.
There are standards for child resistance defining tests such packages should
pass so
as to be acceptable to the market, most notably the international standard ISO
8317.
Child-proof pharmaceutical packages with locking means have been manufactured
of plastics, but more recently also paperboard and cardboard have been
introduced
or suggested as materials for such packages.
EP 1 002 744 Al describes a two piece paperboard package with a child
resistant
locking system arranged between an inner paperboard slide card housing a
product
and an outer paperboard sleeve. For locking the pieces the system has a tab in
the
inner slide coming into contact with a shoulder on the inside of the sleeve.
Releasing the parts takes place by pressing a release button. The paperboard
used is
described as being within the thickness range of 0.2 to 0.7 mm and usually has
clay
coating either on one side surface or on both sides. The coating is taught to
provide
a high degree of smoothness and superior graphic print surface.
A weakness in the mechanism according to EP 1 002 744 A1 is pointed out in WO
02/38454 A1, namely the locking system being dependent on selection of a
sufficiently thick material for the outer sleeve. A material that is too thin
can put the
locking security at risk. The teachings in WO 02/38454 A1 are for an improved
structure in order to achieve locking that is secure and resistant to wear in
repeated
use even if a thin cardboard material is used.
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2
More specifically, the child resistant package described in WO 02/38454 A1
comprises an outer sleeve and a slidable insert made by folding and gluing of
sheets
of cardboard and is provided with a locking system therebetween. The sleeve is
provided on its inside with a catch tab and an operating tab arranged
consecutively
in the sliding direction of the insert beside the opposite side walls of the
sleeve. The
insert is provided with locking tabs, similarly beside its opposite side
walls. For
being made of cardboard the tabs in the sleeve and in the insert are flexible.
As the
insert is pushed into the sleeve the locking tabs slide under the catch tabs
and end
up under the operating tabs. However, the two catch tabs have a downward
inclination in the sliding direction so that they will engage with the locking
tabs to
prevent the sleeve from being drawn out. To open the package the user has to
press
with one hand's fingers the operating tabs against the locking tabs through
tw~
holes in the sleeve, to release the locking tabs from the engagement and thus
allow
withdrawal of the insert from the sleeve by the other hand.
In a previous, so far unpublished international application PCT/SE02/01600
owned
by the present applicant there is described an improved locking system for a
two-
part paperboard package for pharmaceuticals etc. A specific feature of said
package
is the location of the holes for releasing the locking mechanism in the
opposite
edges or side walls of the outer sleeve. Generally the teachings aim at
simplifying
the structure and making it easier to manufacture.
A further prior art two-part carton package for pharmaceuticals is described
in US
6 491 211 B 1. The outer carton is taught to be formed of a blank of any
suitable
material, paperboard of sulfate, clay-coated newsback or recycled paperboard,
having a thickness of 0.008 to 0.028 inch (about 0.2 to 0.7 mm), being
specifically
preferred.
A different type of pharmaceutical packages are press-through or blister packs
comprising a plastics sheet with flexible bubbles and a sheet of rupturable
aluminium foil attached to the plastics sheet. The pills contained in the
compartments or blisters between the sheets are removed by pressing, so as to
force
them through the rupturing foil. In EP 0 771 737 B 1 there is described a
blister
pack, which is made child resistant by providing it with a backing sheet that
cannot
be ruptured, the backing sheet comprising a heat seal layer, a foil layer, a
layer of
polyester of other strong polymer material and an outer paper layer for
printing. The
backing sheet has a nearly invisible score cut as an opening feature to let
the
package be opened by peeling off of the backing sheet, use of the opening
feature
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requiring the cognitive skills of an adult, in contrast to that of a child not
being able
to use it. WO 03/066323 A1 further describes a laminate for child-resistant
blister
packs comprising a heat seal layer, a tear-resistant polymer layer and a
paperboard
substrate for printing. The laminate is provided with areas of controlled
weakness to
direct opening of the package according to instructions, which are easily
followed
by an adult but not by a child.
As a material for disposable consumer packages fiber-based board is generally
preferable to plastics, due to lower material or manufacturing costs and
environmental aspects. However, as carton packages have been subjected to
child
safety tests by the present applicant it has unexpectedly turned out that in
spite of
the advances made, such packages still easily fail to fulfil the requirements.
While
the prior art so far has concentrated on improving the locking mechanism, to
add its
structural rigidity and wear-resistance and to make it resistant to a child's
tampering, the tests reveal that the weak point is no more the design of the
locking
mechanism but rather the material itself. Whether for curiosity or any other
reason,
a child can all too easily open a board package and gain access to its
contents
simply by tearing it apart.
A feature apt to trigger a child's interest in the package is the holes or
other
accessories required by the locking mechanism. However, rather than from the
holes, a child would tear the sleeve starting from the insert opening or the
seals,
where the material will lose integrity and break off.
The object of the invention is thus to provide a carton package of fiber-based
material for pharmaceuticals etc. that overcomes the structural weakness
problem
discussed above. In particular, the invention has the object of providing a
package
which better prevents the access of children to the contents by modification
of the
fiber-based material used for the package. Thereby a package with improved
child
resistance may be obtained while substantially preserving the advantages of
paperboard or cardboard materials in comparison with the all-plastic packages
as
used in the prior art.
The invention has in particular the object of providing added strength for the
package without any need to change its overall design and manufacture, so that
the
improvement is easy to put into practice and, except the material, does not
increase
the manufacturing costs of the package.
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According to the invention the above objects are achieved through a child
resistant
two-part carton package for a pharmaceutical product or other products that
might
be dangerous for children, which has an outer sleeve that is made of board
reinforced with extrusion coated polymer to increase its resistance to
tearing.
The reinforcement may be a layer of tough polymer coated onto the fiber-based
board. Suitable coating polymers for use in the invention are those selected
from the
group consisting of polyester, polyamide, polypropene and polycarbonate,
polyesters being preferred, and among them, polyethylene terephtalate (PET)
being
particularly preferred.
The board may have a polymer coating on one side thereof, this side then being
used for the outer side of the sleeve. A polymer coating covering the outside
of the
sleeve prevents a child from wetting and tearing the material with her teeth.
However, the board is preferably provided on both sides thereof with a coating
layer of a tough polymer. In either case the coating polymer may be used to
form
the heat seals needed to hold the sleeve folded from a blank of the coated
board
together.
More preferably, the board is provided with a multilayer coating comprising an
inner reinforcement layer of a tough polymer such as PET and an outer heat
seal
layer of polyolefin. Such multilayer coating can be on one side or,
preferably, on
both sides of the board. The adjacent layers can be brought to the board
simultaneously by coextrusion.
In a carton package according to the invention not only the sleeve but also
the insert
can be made of board coated with a reinforcement layer of tough polymer.
Especially the end face of the insert closing the open end of the sleeve
advantageously has a polymer coating so that the outside of the package has a
similar polymer reinforcement throughout. Preferably the insert is made of the
same
polymer extrusion coated board as the outer sleeve.
The reinforced board used especially for the outer sleeve of the carton
package may
have such a structure that it delaminates under a sufficient tearing force
subjected to
3 5 its raw cutting edge. It has been found that even in case of such a
rupture the inner
material layers, including a polymer coating on the inside, together with the
heat
sealings may hold the package closed and thus succeed in preventing the child
to
get access to its contents.
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Alternatively, specific measures can be taken to reinforce the cut edges at
least on
the outside of the outer sleeve so that delamination, i.e. peeling off of an
outer
material layer, is prevented in the first place. Skiving and folding of the
edges of a
5 polymer coated board, application of glue to the cut edges, or covering the
edges
with a protecive film may be mentioned as examples of such techniques.
A carton package according to the invention may be constructed so that the
sleeve
comprises four longitudinal side walls parallel to the sliding direction of
the insert,
a rear wall, and an open end to let the insert be drawn out of the sleeve, and
that the
locking mechanism comprises a first stop tab in the sleeve, the first stop tab
extending from a first to a second of the longitudinal walls and being at
least partly
separated from the first longitudinal wall and the second longitudinal wall,
and a
first locking edge provided in the insert, the insert being prevented, upon
contact of
the first locking edge with the first stop tab, from moving out of the sleeve,
while
the first locking edge can, through elastic deforming of a part of the insert
by a user,
be moved so that its movement past the first stop tab is made possible.
For operation of the locking mechanism the outer sleeve may have one or more
holes permitting release of the locking by the user's finger.
The invention also comprises use of polymer extrusion coated board for a child
resistant carton package for a dangerous product such as a pharmaceutical, the
package comprising an outer sleeve, a slidable insert and a locking mechanism
between the outer sleeve and the insert.
The coated board for use according to the invention is as already described. A
board
coated on both sides with a reinforcing tough polymer, such as PET, and a heat
sealing polymer such as polyolefin is thus preferred.
Such a board reinforced with an extruded polymer coating may be used for the
outer sleeve as well as for the slidable insert and would then also form the
locking
mechanism parts of the carton package.
The board base for use in the invention may be kraft board of a weight in the
interval 170 to 500 g/m2, preferably 200 to 300 g/ma. The extruded coating
layers of
PET or other suitable tough polymer may have a weight of 30 to 100 g/m2,
preferably 40 to 60 g/m2. The extruded outer heat seal layers of polyolefin
such as
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low density polyethylene (LDPE) or polypropene (PP) may be of a weight of 15
to
60 g/m2, preferably 20 to 40 g/m2. The coated board is used for the outer
sleeve or
the insert or both, the polymer coating reinforcing the board by way of
increasing
its tearing strength, with benefit to at least 2000 mN and preferably more
than 2500
mN according to standard SCAN-P 11:96.
The invention will be described in detail below with reference to the
drawings, in
which
- Fig. 1 shows a perspective view of a package according to an embodiment of
the invention,
- Fig. 2 shows another perspective view of the package in Fig. 1,
- Fig. 3 shows a manufacturing blank for a part of the package in Fig. 1,
- Fig. 4 shows a perspective view of a part of the package which has been
manufactured from the manufacturing blank in Fig. 3, certain concealed parts
being
marked by broken lines,
- Fig. 5 shows in perspective a cut-out part of the part in Fig. 4,
- Fig. 6 shows a perspective view of a part of the package in Fig. 1,
- Fig. 7 shows a manufacturing blank for the part in Fig. 6,
- Fig. 8 shows a transverse section of a part of the package in Figs 1 and 2,
- Fig. 9 shows as a schematic cross-section a material applicable for the
package according to Figs 1 - 8,
- Fig. 10 shows as a schematic cross-section another material applicable for
packages according to the invention,
- Fig. 11 is a cross-section XI - XI from Fig. 2, showing in a schematic
manner
the material used in the package according to Figs 1 - 8,
- Fig. 12 shows a bottom view of the package corresponding to that in Fig. 1
and
having shielded cutting edges at the seams,
- Fig. 13 shows in cross-section a skived edge portion of a blank for a part
of a
package according to the invention,
- Fig. 14 is a cross-section XIV - XIV from Fig. 12, showing a seam area of
the
package formed by use of the blank in Fig. 13, the seam comprising the skived
edge
portion,
- Fig. 15 corresponds to Fig. 12, showing in a bottom view a variation of the
package according to the invention,
- Fig. 16 shows a bottom view of a further variation of the package according
to
the invention, and
- Fig. 17 shows a part of a still further variation of the package according
to the
invention.
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For its general structure the package shown in Figures 1 - ~ is described in
PCT/SE02/01600, which is hereby incorporated by reference in the present
disclosure. Further examples of package structures with locking mechanisms
applicable in connection with the present invention may be found in WO 02/3454
A1, the latter publication being also incorporated by reference in the present
disclosure.
Figure 1 shows a package 1 according to a preferred embodiment of the
invention.
The package comprises an outer sleeve 2 of essentially parallelepipedal shape,
and
an insert 3 intended to hold the contents of the package. The sleeve 2 and the
insert
3 are preferably produced by folding and heat sealing blanks made of extrusion
coated cardboard material (see below). The insert 3 can be inserted into and
withdrawn from the sleeve 2 in a sliding direction S, indicated by a double
arrow in
Fig. 1, through an opening 4 in the sleeve 2. Fig. 1 shows the package 1 in
the
completely inserted state of the insert. Fig. 2 shows the package 1 in a
partly
withdrawn state of the insert 3, access to the contents of the package being
possible.
The sleeve 2 comprises four longitudinal walls which are essentially parallel
to the
sliding direction S. The longitudinal walls are an upper wall 2a, a lower wall
2b, a
first side wall 2c and a second side wall 2d, the upper wall 2a and the first
side wall
2c being visible in Figs 1 and 2.
At the opening 4, the side walls 2c, 2d each have gripping notches 5, at each
of
which the insert 3 can be gripped by a finger in order to be drawn out. The
width of
the package is preferably adapted so that the insert 3 can be gripped only by
people
who have sufficiently large hands for this. This means that small children
cannot
reach across the width of the package with a thumb/forefinger grip in order to
draw
the insert 3 out.
At one end, the insert 3 preferably has a beam-like part 6 which is produced
by
folding an insert blank (see below). The beam has such stiffiiess that it is
impossible
or extremely difficult for a child to deform the end of the insert and in this
way
reach the contents of the package.
At the opening 4, the sleeve 2 preferably has two tabs which are folded
inwards
essentially parallel to the upper wall 2a and the lower wall 2b, respectively,
(see
below). This means that an upper and a lower edge at the opening 4 are
reinforced,
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making it impossible or difficult for children to tear open the sleeve 2 at
these edges
in order to reach the contents of the package.
Fig. 3 shows a sleeve blank 2' made of extrusion coated cardboard, which is
formed
into the sleeve 2 by folding and heat sealing. As can be seen in Fig. 3, the
sleeve
blank 2' comprises the two tabs 21, 22 which, as mentioned above, reinforce
the
opening 4 of the sleeve by being folded inwards essentially parallel to the
upper
wall 2a and the lower wall 2b, respectively.
The sleeve blank 2' comprises a first portion 2a' intended to form the upper
wall 2a
of the sleeve and a second portion 2b' intended to form the lower wall 2b of
the
sleeve. A third portion 2c' and a fourth portion 2c" are intended to form the
first
side wall 2c of the sleeve, the fourth portion 2c" being intended to be
positioned
inside the third portion 2c'. In a corresponding way, a fifth portion 2d' and
a sixth
portion 2d" are intended to form the second side wall 2d of the sleeve.
A seventh portion 7a' and an eighth portion 7b' are intended to form a first
stop tab
7a and a second stop tab 7b, respectively, which act to bring about locking of
the
insert 3 in the sleeve 2, which is described in greater detail below. As can
be seen in
Fig. 3, the portions 7a', 7b' which are to form stop tabs have an essentially
triangular shape, one of the points of the triangle being located at a free
longitudinal
edge on the fourth portion 2c" and the sixth portion 2d", respectively. The
seventh
portion 7a' and the eighth portion 7b' proj ect outside the free longitudinal
edge on
the fourth portion 2c" and the sixth portion 2d", respectively, and they are
intended
to be folded at respective lines 7a", 7b" inside said free edges.
Alternatively, the portions which are to form stop tabs can have a shape other
than
triangular, for example rectangular.
When the sleeve blank is folded, the fourth portion 2c" and the sixth portion
2d"
are folded so that their free longitudinal edges are positioned at the
connection
between the upper wall 2a and the first side wall 2c and the second side wall
2d,
respectively, of the sleeve. The seventh portion 7a' and the eighth portion
7b' are
then folded so that they are positioned at an angle to the upper wall 2a and
the first
side wall 2c and the second side wall 2d, respectively, of the sleeve; they
then form
the first stop tab 7a and, respectively, the second stop tab 7b. Each stop tab
is
therefore connected to the respective side wall and forms an angle in relation
to the
same by bearing against the upper wall.
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Fig. 4 shows the folded-together and heat sealed sleeve with certain concealed
parts
marked by broken lines. The first stop tab 7a and the second stop tab 7b are
located
on the inside of the sleeve, in respective corners formed by the upper wall
2a, and
the first side wall 2c and the second side wall 2d, respectively. The first
stop tab 7a
and the second stop tab 7b are also located at a distance from a rear wall 2e
of the
sleeve 2.
Fig. 5 shows, for the sake of clarity, a part of the sleeve 2 cut out, in
perspective at
an angle from below. The second stop tab 7b extends from the inside of the
second
side wall 2d to the inside of the upper wall 2a. The stop tab 7b therefore
extends at
an angle to the walls 2a, 2d of the sleeve so that at least a part of it is
located in a
part of the area for the movement of the insert 3 in the sliding direction S.
As
described in greater detail below, the stop tab 7b acts by contact with the
insert 3 in
order to prevent the latter from being drawn out of the sleeve 2. The fact
that the
stop tab 7b extends inside the walls of the sleeve and is separated from these
ensures that its functioning is not sensitive to wear of the same after
repeated use.
Furthermore, a solution is achieved, in which the stop tab is separated from
the
sleeve walls without a means, such as a projecting part, intended especially
for the
purpose being required.
As can be seen in Fig. 5, the stop tab 7b is also angled in relation to the
sliding
direction S of the insert 3, so that that part of the stop tab located closest
to the
opening 4 of the sleeve is located closer to the sleeve walls 2a, 2d than the
other
parts of the stop tab. By virtue of this, when the insert is inserted into the
sleeve,
parts of the insert 3 intended for locking, which are described in greater
detail
below, can, by elastic deformation on contact with the stop tab 7b, pass the
latter
and "snap" back after passing. This design of the stop tab 7b also means that
it is
very strong and can withstand great forces when attempts are made to draw it
out
without an unlocking manoeuvre as described below.
Fig. 6 shows the insert 3, and Fig. 7 shows a blank 3' for manufacturing an
insert by
means of folding and if appropriate heat sealing. The insert blank comprises
portions 6' for making the beam 6 mentioned above.
The insert 3 comprises a bottom part 3a, a first side part 3b and a second
side part
3c. In the inserted state of the insert, the side parts 3b, 3c are located
essentially
parallel to and next to the side walls 2c, 2d of the sleeve 2. The side parts
3b, 3c
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extend essentially in the sliding direction S, intended for the insert, in the
sleeve 2.
They are connected to the bottom part 3a and are oriented essentially at right
angles
thereto.
5 Each side part 3b, 3c has a notch 8a, 8b. At the notches, a first locking
edge 9a and
a second locking edge 9b are formed, respectively. In the inserted state of
the insert,
the locking edges 9a, 9b are located slightly closer to the rear wall 2e of
the sleeve
than the stop tabs 7a, 7b, and, if attempts are made to draw the insert out of
the
sleeve, this is prevented by virtue of the side parts 3b, 3c coming into
contact, in the
10 area of the locking edges 9a, 9b, with the first stop tab 7a and the second
stop tab
7b, respectively.
As can be seen in Fig. 3, the sleeve blank 2' has holes 10a', 10b', referred
to as
outer holes 10a', 10b' below, on the third portion 2c' and the fifth portion
2d', and
holes 10a", 10b", referred to as inner holes 10a", 10b" below, on the fourth
portion 2c" and the sixth portion 2d". The inner holes 10a", 10b" are each
covered by a flap 101 which, at an essentially straight edge of the respective
inner
hole, is connected to the sleeve blank so that the flap is pivotable about the
straight
edge.
In the finished state of the sleeve 3, the first side wall 2c and the second
side wall
2d comprise parts of the third and the fourth portion 2c', 2c", and the fifth
and the
sixth portion 2d', 2d", respectively. In this regard, the third portion 2c'
and the fifth
portion 2d' are located outside the fourth portion 2c" and the sixth portion
2d",
respectively. The flaps 101 and the outer holes 10a', 10b' are adapted in
terms of
size so that the flaps 101 extend outside the area of the respective outer
hole 10a',
10b' so that they are pivotable only inwards in the package. The flaps are
then
prevented from being moved outside the package and in this way being damaged.
As can be seen in Figs 1, 2 and 4, the inner holes 10a", 10b" and the outer
holes
10a', 10b' form, in the finished folded sleeve 2, a first hole 10a and a
second hole
lOb in the first side wall 2c and the second side wall 2d, respectively. The
package
is adapted so that a user can grip across the package with a thumb/forefinger
grip.
The user can then press a finger on each of the holes 10a, lOb in order to
move the
flaps 101 inwards and, on the inside of the sleeve, to press the side parts
3b, 3c of
the insert so that these, at least in the area of the locking edges, are
deformed
elastically so that they are inclined inwards in the sleeve 2, which can be
seen in
Fig. 8 (where only one side part 3c is shown). The locking edges 9a, 9b are
then
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11
moved away from the side walls 2c, 2d of the sleeve. In this way, the locking
edges
9a, 9b come to lie, seen in the sliding direction S of the insert 3, outside
the area of
the extent of the stop tabs 7a, 7b, and the insert can, by means of a
thumb/forefinger
grip at the gripping notches 5 (described above with reference to Figs 1 and
2) with
the other hand of the user, be drawn out of the sleeve.
The width of the package is preferably adapted so that people with small
hands, for
example children, cannot reach across the package with thumb and forefinger in
order to manoeuvre the locking by the locking edges 9a, 9b. Opening of the
package therefore requires the use of two hands of the size of those of a
normal
adult.
The design of parts intended for locking in longitudinal side parts of the
insert
results in a strong construction, and thus in combination with a reinforced
board a
reduced risk of the insert being drawn out by force, for example by a child.
Fig. 9 is a schematic cross-section of a coated board applicable for the
carton
package described above with reference to Figs 1 - 8. The coated board would
form
the blanks shown in Figs 3 and 7, and thereby the entire package, i.e. the
sleeve and
the insert, and thus also the locking mechanism which is part of the sleeve as
described.
The coated packaging board 11 of Fig. 9 comprises a board base 12, which is
preferably a multilayer kraft board of a weight in the interval 170 to 500
g/m2,
preferably 200 to 300 g/m2. On both sides of the kraft board base 12 there is
an
extruded layer 13 of tough polymer, preferably polyethylene terephtalate
(PET),
each PET layer having a weight of 30 to 100 g/m~, preferably 40 to 60 g/ma.
The
multilayer structure may be symmetrical with respect to the board base 12, the
PET
layers on opposite sides of the board base then having similar coating weight.
The coated board 11 shown in Fig. 10 differs from that shown in Fig 9.
principally
in that there is an extruded polymer coating layer 13 only on one side of the
board
base 12. The material and weight of the board base may be as above, and the
single
polymer layer preferably is a PET layer having a weight of 30 to 100 g/m2,
preferably 40 to 60 g/m2. In making the package the PET coated side of the
board
would be used to form the outer surface of the sleeve and the insert.
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12
Fig. 11 shows the coated board 11 preferably used for the package described in
Figs
1 - 8. The coated board of Fig. 11 corresponds to that shown and described in
connection with Fig. 9 above, but has an outer heat seal polymer layer 14,
preferably of LDPE, on both sides thereof. Each of the LDPE layers 14 has a
weight
of 15 - 60 g/m2, preferably 20 - 40 g/m2. The PET and LDPE layers 13, 14 may
be
brought to the fibrous board base 12 at a single manufacturing step by
coextrusion.
In the manufacture of the package 1 the polymer coating layers 13, 14 are used
to
form the heat seals as required in the sleeve and in the insert. Fig. 12 shows
the
bottom side of the sleeve 2 comprising two parallel seams 15, in which two
opposite edges of the sleeve blank 2' have been brought to overlap with the
lower
wall portion 2b'. In the case of the boards 11 with polymer coatings on both
sides
as shown in Figs 9 and 11 the coating layers 13 or 14 on the overlapped parts
of the
blank are fused together by means of heat sufficient to melt the polymer. In
the case
of the singly coated board of Fig. 10 the overlapped parts are sealed by
melting the
single polymer layer 13 on one part to attach it to the adjacent uncoated
board
surface of the other part.
Figs. 13 and 14 show as a further embodiment of the invention protection of a
seam
15 of the outer sleeve 2 against delamination of the coated board.
Delamination
starting from an exposed seam 15 on the outside of the package is one of the
possible ways of disruption the package may suffer in children's hands.
Delamination could occur either by the polymer coating peeling off from the
board
base or between adjacent layers of a multilayer fibrous board.
In Fig. 13 an edge portion 16 of a blank 2', which is made of a coated board
11 as
shown in Fig. 11 and has the design as shown in Fig. 3, has been skived from
one
side of the blank, to reduce its thickness approximately to a half. It should
be
understood that such skiving is carried out particularly for the parts of the
blank 2'
forming exposed seam edges 15 on the outside of the finished sleeve 2.
In Fig. 14 such a seam is shown between overlapped parts 17, 18 of the blank
2' of
Fig. 13 as it has been folded and heat sealed to form the sleeve 2. The part
17
having the skived edge portion 16 is the outer board part at the seam, lying
on the
outside of the sleeve, more particularly in its bottom as the blank 2' and the
sleeve 2
have the configurations as seen in Figs 3 and 8, respectively.
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As seen in Fig. 14 the skived edge portion 16 of the outer board part 17 with
reduced material thickness has been bent twofold, the outside coating layers
thus
enclosing the fibrous board base 12 at the seam edge 15 and extending to lie
against
the outside coating layers of the inner board part 18. The seam between the
parts 17,
18 has been produced by heat sealing the adjacent heat seal layers 14, 14'
within an
area denoted as 19 in Fig. 14, the outer heat seal layer 14° of the
inner part 18 being
fused together with parts of the inner as well as the folded outer heat seal
layer 14
of the outer part 17. If desired, an adhesive may be applied to the raw board
base 12
surface produced by the skiving so as to provide inner structural strength for
the
fold.
An alternative manner of shielding the seams 15 against delamination would be
application of glue on the cut raw edges thereof, so as to close the pores in
the
fibrous board base 12. Preferably such gluing would be carried out for any cut
edge
portions exposed to the outside of the package 1.
In the embodiment shown in Fig. 15 the edge portions of the blank 2' forming
the
seams 15 have been extended to bring the cutting edges into a protective
contact
with each other, to make them resist tampering and the risk of delamination.
Fig. 16 shows as a further embodiment shielding of the raw cut edges at the
seams
15 as well as around the holes 10 of the sleeve 2 by covering them with an
adhered
protection film 20 of a tough plastic material. According to Fig. 17 similar
protective film 20 has been applied around the opening part 4 of the outer
sleeve 2,
to shield the cut edges 21 thereof against tampering and delamination.
Otherwise
the material for the sleeve 2 may be any one of those described in connection
with
Figs. 9 - 11.
Example
A coated board was prepared by using packaging board of grade Cupforma Classic
by Stora Enso, having a weight of 210 g/m2, as board base. This board was
extrusion coated on one side or on both sides thereof with a PET layer of a
weight
50 glm2. The tearing strengths measured according to the standard SCAN-P 11:96
are presented in the following table:
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TABLE
Coating on Coating on
both sides one side Uncoated
Tearing strength m.d. (mN) 3114 2724 1902
Tearing strength c.d. (mN) 3083 2904 1924
m.d. = machine direction
c.d. = cross-machine direction
A package according to Figs 1 - 8, made by gluing of a packaging board grade
with
a weight of 250 g/ma and having a PET coating layer of 50 g/m2 on both sides
thereof, was subject to a successful pilot child resistance test according to
standard
ISO 8317. For comparison, a similarly designed package manufactured of a
packaging board grade with a weight of 315 g/m2 and without the PET coating
layers failed in a corresponding test.
