Note: Descriptions are shown in the official language in which they were submitted.
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CLOSED MULTI-LAYER PACKAGING AND PACKAGING MATERIAL
FIELD OF THE INVENTION
The present invention relates to closed, and in particular -
sterile, multi layer packaging that is generally rectangular in
shape and made from at least one multi-layer strip shaped into
a tube having overlapping longitudinal margins that are sealed
to each other in fluid-tight manner, the multi-layer strip
comprising from the inside towards the outside of the
packaging: an inside layer of thermoadhesive thermoplastic
material, optionally a gas and light barrier film together with
a layer for bonding it to the following layer, a support layer
made of a relatively rigid material such as card, and
optionally a thin covering layer of thermoadhesive thermo-
plastic material, the terminal portion of the inside layer of ~-
the "inside" margin of the two longitudinal margins of said
multi-la~er strip being folded outwards a~d rearwards and being ;~
heat-sealable to the inside layer of the "outside" other
longi*udinal marginO ~ -
BACKGROUND OF THE INVENTION
In this type of prior art packaging as described, for
example, in European patent No. 0 124 772, one of the
longitudinal margins of the multi-layer strip is partially cut
down from its outside face through about one half of its ~
thickness, such that there remains a portion of the thickness :
of the card support layer together with the layers beneath the
cut down portion of the card, which layers include the inside
layer o thermoadhesive thermoplastic material. In -this case,
one-half of the cut-down portion of the longitudinal margin is
folded outwards and onto itself in such a manner that the
inside layer co~es into alignment with the outside layer of
said margin and can be heat sealed directly to the inside layer
of the "outside" other margin of the tube-shaped multi-layer
strip. In order to ensure good sealing at the junction between
the two longitudinal margins of the multi-layer strip, the
cutting down and the folding of the cut-down portion must be
performed with high accuracy, and the outside margin must not
only overlie the folded-over portion of the cut-down portion
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but it must also overlie the adjacent zone of the inside
margin. Given the thicknesses of the layers in question and
the speed at which packaging is fabricated, it is very
difficult or impossible to satisfy this requirement for
accuracy, and it often happens that because of faulty sealing
between the outside margin of the cut-down folded-over portion
of the inside margin, the cut-down card is e~posed to moisture
by the liquid substance contained inside said packaging. The
cut-down edge or margin of ths card support layer thus comes
directly into contact with the liquid such that said layer of
card swells by degrees and this swelling leads to localized
destruction of the seal between the two superposed margins,
thereby destroying the fluid-tightness of the packaging.
Proposals are made in European patent No. 0 006 259 to
fabricate rectangular packaging by using a multi-layer strip
whose margins are not cut down, and to cover the junction zone
of the two longitudinal margins of the strip inside the '~
packaging with a sealing tape so as to prevent the liquid
coming into contact with the bare edge of the card layer, with
the thermoplastic sealing tape adhering in fluid-tight manner
to the inside face of the packaging, and m~re precisely to the
inside face of the inside longitudinal margin, and to the
inside face of a zone of the strip immediately adjacent to the ~-
outside margin and overlying the inside margin so as to leave a
kind o longitudinal channel between the edge of the inside
margin and the adjacent zone of -the outside margin of the tube-
shaped packaging strip.
Manipulating this sealing strip inside the tube having
ovexlapping lonyitudinal margins is complicated, as is applying
the tape against the inside face of the packaging. In addition,
the slightest sealing fault associated with this sealing tape
renders the entire channel and thus the entirs layer of card
accessible to moisture from the packaged material.
American patent No. 4 589 591 proposes folding onto itself
the inside margin of the multi-layer strip that is shaped into
a tube and heat-sealing the outside margin with its inside
layer of thermoplastic material on a part of the inside layer
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of the folded-over portion of the inside margin and on an
adjacent part of the card layer belonging to the non-folded
over portion of said inside margin, with the junction zone
between the two longitudinal margins being at a distance from ;
the fold zone of the inside margin. This technique initially
prevents moisture from the liquid contained inside the
packaging reaching the card layer. However, the fold in the
inside margin gives rise to a thick rim which is difficult to
heat-seal onto the outside margin and it leaves tubular gaps
parallel to the longi-tudinal margins, so outside moisture can
penetrate into these gaps and cause the card to swell until it
breaks the heat seal between the two margins. In addition,
folding the inside margin and sealing the outside margin onto a
non-folded portion of ths inside margin means that a wider
15 strip must be provided and gives rise to wasted quantities of ~ ~
multi-layer strip for a given volume of packaging. ~ - i
An object of the present invention is to eliminate these
drawbacks, or at least to attenuate th~m.
SUMMARY OF THE INVENTION
This object is achieved by the fact that in the junction
zone either between two heat-sealed longitudinal margins of the
same multi-layer strip or between a longitudinal margin of a
first multi-layer strip and a longitudinal margin of a second
multi-layer strip, the terminal portion of the inside layer of
thermoplastic material of the "inside" longitudinal margin
situated on the inside of the packaging is formed by a
protective flap which projects from said inside margin over a
short but sufficient distance from the superposed and aligned
edges of the other layers or films of the same margin, and is
folded outwards so as to overlie the edges of said other layers
or films in fluid-tight manner and also overlie an adjacent
marginal zone of the outside face, of said strip and adhere
thereto, and in that the "outside" other margin of the strip is
heat-sealed to the outside facei of the inside margin, the
*olded-over portion of the flap extending the thermoplastic
inside layer o the inside margin and heat sealed to the
outside face thereof being interposed between the thermoplastic
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inside layer of the outside margin and said outside face of
said inside margin, said flap adhering in fluid-tight manner to
each of said margins.
By virtue of this design, the edge of the layer of card ~-
is directly covered by the protective flap which simultaneously
cont-ributes to improving the junction between the inside margin
and the outside marginO All harmful gaps are eliminated from
the zone where the flap is folded and from the width of the
overlap zone, and the thickness thereof is kept down to the
strict minimum required for providing long-lasting fluid-tight
sealing.
The present invention also relates to a packaging material
in the form of a multi-layer strip comprising an "inside" layer
of thermoadhesive thermoplastic material for subsequently
constituting the inside face of the packaging, and a support
layer of card adhering to the insid~ layer either directly or
else indirectly via a light and fluid barrier layer and an
adhesive layer between said support layer and said barrier
layer, and optionally also comprising an outside covering layer
20 of thermoadhesive thermoplastic material. ~
Packaging material in the form of a multi-layer strip of ;~-
this type has longitudinal margins at which the various layers
of the strip are apparent (see European patent No. 0 006 259),
or are poorly protected (European patent 0 124 772, US patent
4 589 591). As a result, within a relatively short period of
time, the portion of the card layer lying in the junction zone
between the t~70 longitudinal margins is in danger of coming
into contact with external moisture or with moisture from the
liquid contained inside the packaging, and the resulting
swelling of the card causes the fluid-tightness of the
packaging to be broken.
An object of the present invention is to eliminate this
drawback.
To this end, the inside layer of the multi-layer strip is
extended laterally along at least one side so as to form a
protective flap which pro~jects beyond the superposed lateral
edges o all the other layers of said strip by a suffiaient
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distance to be capable of being folded over said superposed
edges to overlie in fluid-tight manner both said edgas and a ` ~
marginal zone of the outside face of said strip, which zone ~ - -
subsequently has the other margin of the same strip or one of ~ -
the margins of a second multi-layer strip applied thereagainst.
Thus, the means required for sealing the edges of the
inside margin of the packaging are already partially attached
to the multi-layer s~rip, thereby significantly facilitating
fabrication of the final packaging.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described by way of
example with reference -to the accompanying drawings, in which:
Figure 1 is a perspective view of closed packaging made
from at leas-t one multi-layer strip, with a portion of the
15 strip being shown having its layers separated from one another; ;- -
Figure 2 is a diagrammatic elevation view in cross-section
through a first embodiment of the packaging material;
Figure 3 is a diagrammatic elevation view in cross-section
through packaging while it is being fabricated from a single
multi-layer strip material as shown in Figure 2;
Figure 4 is a diagrammatic elevation view in cross-section
through packaging made from a single multi-layer strip as shown
in Figure 2, this view showing more particularly the junction
zone between two longitudinal margins of said strip; ~
Figure 5 is a diagrammatic elevation view in cross-section ;~-
through packaging made from two multi-layer strips of the type
shown in Figure 1;
Figure 6 is a diagrammatic elevation view in cross-section
through packaging made from two multi-layer strips one of which
(to the right in the figure) is a conventional multi-layer
strip while the other one is a multi-layer strip as shown in
one or other of Figures 8 and 9;
Figures 7 to 9 are diagra~natic elevation views through
various different embodiments of a single multi-layer strip:
and
Figures 10 and 11 are diagrammatic elevation views through
two embodiments of a set of two multi-layer strips adhering to
each other via their inside layers.
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DETAILED DESCRIPTION
The closed multi-layer packaging of the present
description has a sterile inside face and is generally
rectangular in overall shape, or is similar in shape~ This
type of packaging is made from at least one multi~layer strip
or from two multi-layer strips whose margins overlap and are
bonded together in fluid-tight manner. Methods of fabricating
packaging of this type which is filled while it is being
fabricated are widely known, e.g. *rom French patents Nos. -
1 192 6g7 and 1 198 792, from Swiss patent No. 621 744, and
from European patents Nos. 0 083 131 and 0 302 413, to name but
a few, so the present description is limited to the essential
features of the present invention.
~s can be seen in Figure 1, the packaging material from
which rectangular packages 1 are made and filled with a liquid
and/or semi-liquid substance of varying degrees of viscosity
while the packaging is being fabricated and prior to final
sealing comprises at least one multi-layer strip 2 comprising
from the inside towards the outside of the package 1: an inside
layer 3 of thermoadhesive thermoplastic material such as
polyethylene; an optional barrier film or layer 4 which is gas-
tight and lightproof such as aluminum foil or the like,
together with a thermoadhesive bonding layer 5 for establishing
a secure bond with the following layer 6 which is a support
layer made of a material such as card that is relatively stiff
but capable of being folded; plus an optional thin covering
layer 7 made of thermoadhesive thermoplastic material such as
polyethlene.
Naturally, the composition of the multi-layer strip 2 is
30 not limited to that described above by way of example, -
particularly since the invention does not relate to a multi-
layer strip of a given composition but relates to a multi-layer
strip which includes a thermoplastic inside layer 3 and a
support layer 6, with the number and nature of other layers in
the strip 2 being variable, depending on re~lirements ~see
Figure 2).
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As can be seen in the drawings, and in particular in
Figures 2 to 7, the inside layer 3 projects laterall~ from at -;
least one side so as to form a pro-tective flap 8 running along ~ ~ -
the entire length of the multi-layer strip 2 and projecting
beyond the lateral edges (or sides of the margins) 9 of all the
other superposed layers 4, 5, 6, and 7 of said strip 2 by a
distance d which is sufficient to enable it to be folded back
over said superposed edges 9 so as to cover said edge 9 and a
marginal zone lOa o~ the outside face 10 of said strip 2 in
10 sealed manner, which marginal zone lOa subsequently has the ;
other margin 2b of the same strip 2 (Figures 3 and 4) or one
(e.g. 102a) of the longitudinal margins (102a, 102b) of a
second multi-layer strip 102 (Figures 5, 6) applied
thereagainst in ~luid-tight manner by heat-sealing.
Figure 3 shows a tube 11 formed from a single multi-layer
strip 2 with the major portion of the periphery of the tube 11
being represented diagra~natically by dashed lines. In this ~ :
case, the inside face of the flap 8 extending the inside layer
3 along one of the sides of the strip 2 beyond the edges 9 of
the other layers 4 to 7 is heat-sealed in the softened state
under the action of determined pressure P against the inside ,;, ,
face of the inside layer 3 of the other margin 2b of the same
multi-layer strip 2 so that the longitudinally-extending edge
of the flap 8 comes into alignment with the edges of the other
25 margin 2b of the strip 2 (Figure 3). The following operation :~
in ~abrication of the packaging 1 consists in folding the
assem~led flap 8 and margin 2b over the entire width d of the
flap 8 around the bare edges 9 of the first margin 2a of the !~
strip 2 without leaving any ga~ between said flap 8 iand said
edges 9, and in heat-sealing the flap 8 over at least a portion
of its width d and preferably over its entire width d to the -
adjacent marginal zone lOa on the outside face 10 of said strip
2 (see Figure 4, for example). This provides a permanent and
fluid-tight bond between the two margins (e.g. 2a, 2b) of a
35 single strip 2 or of two strips 2 and 102 while simultaneously ~
protecting the support layer 6 against any edge-on ~ -
infiltration of dampness.
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As mentioned above, in the finished packaging 1, the
protective flap 8 overlies the outside face 10 of the inside
margin 2a of the tube 11 and of the resulting packaging 1,
covering a marginal zone lOa whose width corresponds (ignoring
the thickness of the layers 4 to 7) to the width of the zone
over which the inside margin 2a and the outside margin 2b are
heat-sealed together. Naturallyr the flap 8 is itself heat
sealed to the outside face 10 of the inside margin 2a of the
tube 11 or of the packaging 1 over at least a portion of the
overlaid marginal zone. The protective flap 8 preferably
overlies the outside ~ace 10 of the inside margin 2a o the
tube 11 over the entire marginal zone lOa having the outside
margin 2b o~ the tube ll or of the packaging 1 overlying it,
and it is heat-sealed over the entire marginal zone lOa both to
the outside face 10 of the inside margin 2a and to the inside
layer 3 of the outside margin 2b of the multi-layer strip 2.
In general, -the term "inside margin" designates that or
those margins of a multi-layer strip whose outside face 10, lOa -
is partially overlaid by the protective flap 8 and which is/are
20 to be found inside the packaging 1 or tube 11, while the term ~
"outside margin" designates that or those margins o a multi- ~ -
layer strip not including the protective flap and to be found
on the outside of the packaging 1 or of the tube 11.
As can be seen in Figures 8 and 9, the multi-layer strip 2
has an inside layer 3 which projects laterally along both sides
so as to form two protective flaps 8 and 108, each of which
projects beyond the superposed lateral edges 9 and 109 on the
same side and corresponding to all of the other layers ~ to 7
of said strip, with the flap extending a distance d which is
sufficient to enable it to be folded over said superposed edges
9 or 109 and to enable it to overlie in sealed manner both said
edges 9 or 109 and a marginal zone lOa or llOa of the outside
face 10 of said strip 2.
In this case, the pac~aging 1 or tube 11 is made using
this irst multi-layer strip 2 and using a conventional second
multi-layer strip 102, i.e. a strip 102 that does not include
protective flaps, with one (102a) of the two "outside" margins
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(102a, 102b) thereof being heat~sealed via its inside layer 103
to the flap 8 after the flap has been folded into place, and
being bonded thereby to the outside face 10 of the first inside
margin 2a of the first strip 2, while the other outside margin
102 is heat-sealed in the same manner to the flap 108 and via
the folded-over portion thereto to the outside face 10 of the
other inside margin 2a' of the first multi-layer layer strip 2
(Figure 6). -
As can also be seen in Figure 9, the width 2L of the
multi-layer strip 2 between its two margins (edges 9 and 109),
i.e. its width not counting the protective flaps 8 and 108, is
twice the width L of a strip as used for making packaging 1
from a single strip. The type of multi-layer strip as shown in
Figure g may be split on a vertical plane 13 into two separate '~
15 strips each having one protective flap, as in -the example of ~ `
Figure 2. ~ -
In order to avoid recourse to chemical sterilization of
the inside layer 3 of the multi-laye~ strip, it is possible in
conventional manner to sterilize said layer 3 including its
flap(s) 8 and/or 108 during hot extrusion thereof and to cover
the face that is subsequently on the inside of the packaging 1 ~ `~
with a peel-off protective sheet 14 whose face adjacent to said
inside layer 13 is likewise sterile. Like the inside layer,
the peel off sheet may be made of a thermoplastic material of `
25 the polyethylene type (Figures 7 and 8). -;
Figure 5 shows packaging 1 or a tube 11 made from two
multilayers strips 2 and 102. The first inside margin 2a of
the first strip 2 includes the flap 8 which is folded outward~
in the above-described manner and which is heat-sealed onto the
30 marginal portion lOa of the outside ace 10. The inside layer ~-
3 at the outside margin 102b of the second multi-layer strip ;
102 (which margin 102b does not have a flap) is also heat- ~
sealed to said flap 8. In similar manner to the first strip 2, ;;
the inside margin 102a of the second strip 102 is provided with
a flap 108 extending the inside layer 103, and after being
folded round the edges 109 of the corresponding margin this flap
is heat-sealed to the outside face 110 of the second strip 102,
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after previously being heat-sealed, e.g. by foldiny, to the
inside layer 3 of the outside margin 2b of the first strip 2.
In other words, in the junction zones, each of the two
strips 2, 102 includes an inside layer 3, 103 along a first
margin designed to constitute an inside margin 2a, 102a of the
packaging 1, which inside layer 3, 103 is extended laterally by
means of a protective flap 8, 108 that is folded outwards so as
to overlie the edges 9, 109 of the other layers 4, 5, 6, and 7
of said strip in sealed manner and also overlie a marginal zone
adjacent to the outside face 10, 110 of said strip and adhere
thereto. The second margin 2b, 102b of each strip 2, 102
overlies the adjacent first margin 102a, 2a of the other strip
102, 2 and it is heat-sealed to the inside layer 103, 3 thereof
via the folded-over portion of the flap 8, 108 overlying said
15 first margin 2a, 102a of the other strip (2, 102). i
The packaging may be made up from two multi-layer strips
2, 102 with a first margin on a first strip being heat-sealed
onto one of the margins of the second strip and with the second
margin being heat-sealed to the other margin of said second
strip. In this case, the first strip 2 includes two lateral
margins 2a, 2a' each of which is covered by one of the margins
102a, 102b of the second strip 102, and the inside layer 3 of
the first strip 2 is extended laterally along both sides by
respective protective flaps 8 and 108 each of which is folded
outwards to o~erlia the edges of the other layers of said first
strip 2 in sealed manner and also to ove-rlie an ad~acent
marginal zone of the outside ace 10 of said first strip 2 and
to adhere thereto. Each of the margins 102a and 102b of the
second strip 102 overlying a corresponding margin of the first
strip 2 is heat-sealed via its inside layer 103 onto the
folded-over portion of the corresponding edge 8, 108 of the
adjacent ma-rgin 2a, 2a' of said first strip 2.
In packaging material of the invention, the peel-off
protective sheet may be constituted by the inside layer 103 of
~ second multi-layer strip 102. In one case, an intermediate
film of silicone wax or similar material 15 is interposed
bet~een the inside layer 3 of the first multi-layer strip 2 and
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the inside layer 103 of -the second multi~layer strip 102, with -
the intermediate film 15 being constituted in such a manner
that it remains attached to one or other of the inside layers
3, 103 during peeling and moves off the surface thereof under
the effect of pressure during the heat-sealing operation
( FigurP. 10 ) . , ,
In another embodiment of the packaging material, the peel~
off protective sheet may be constituted by the inside layer 103
of a second multi-layer strip 102 which adheres directly in ~ -
10 peel-off manner to the inside layer 3 of the irst multi-layer ~ ~`
strip 2, with each of the inside layers 3 and 103 being
constituted by a polyolefin, and in particular by heat-sealable
grafted polyethylene. It should be observed that when the two
multi-layer strips 2 and 102 are stuck together in peel-apart ~;
manner, it is advantageous for them to be superposed in offset
manner so that the protective flap 8 or 108 of each strip is
supported by the stiff portion of the other multi-layer strip.
This packaging material is made continuously by extrusion and
by gluing thermoplastic layers on non-thermoplastic layers `,
(card or aluminum foil), it being understood that the two
inside layers are extruded separately and brought together
after extrusion but while they are still sufficiently hot.
They may also be extruded separately at slightly different
temperatures (e.g. with a temperature difference of 20C to
25 30C) and brought together immediately after being extruded ~
separately. ;
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