Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2~253
~091/10~93 PCT/AU91/0001;
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S Field of the Invention
This invention relates to an improved packaging
method and relates particularly but not exclusively, to a . :~
packaging method for red meats~
Description of Prior Art
Hitherto there have been many proposals for the
packaging of perishable goods such as foodstuffs and in ~
particular red meats. Certain examples are disclosed in ~.S. : ~ ;
patènt specification nos. 4,685,274, 4,840,271 and published ;~
PCT patent specification no. PCT/AU87/00297 and PCT patent
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W091/105g3 PCT/A~91/0001~ ;
specification PCT/AU87/00243. The inventor herein is the
inventor in respect o~ the aforementioned - ~-
patents/applications. The subject matter of the published
specifications relating to the a~orementioned
5 patents/applications is hereby incorporated by reference.
In the aforementioned specifications there is
disclosed the use of a plastics material base, goods on the
base, a plastics material flexible web which skin packs or
partially skin packs the goods to the base and a lid over the
l0 base. The base and the lid are substantially gas impervious
whilst the flexible web is gas permeable. A gas for enhancing
preser~ation of the packaged goods is provided in a space
between the lid and the flexlble web. In use, the gas
permeates the flexible web and enhances preservation of the
15 packaged goods.
It has been found desirable to provide a slightly
different type of packaging where the goods are packaged
together with a desired gas, such as N2 substantially with all
unwanted gases removed. To exclude substantially, all of the
20 unwanted gases presents considerable difficulty particularly
in commercial production environment where considerable
packaging throughput is required. This desired gas is
re~erred to as inert in the food packaging arts because it
does not substantially affect the goods and keeps bacteria
25 growth to a minimum. Other gases than N2 can be used such as
CO2, SO2, S2O3, and others, all known for enhancing
preservation. An appropriate one or more of these gases is
chosen to suite the goods which are packed. The goods, such
as red meats, are expected to discolour with time. The
30 packaging is then processed as by opening or rupturing the lid
so that oxygen or other suitable gas can contact the skin
packaging web and permeate that web to attempt to restore an
original colour to the packaged goods.
If unwanted gas such as 2 remains in the packaging
35 with the lid, red meat will discolour dark brown with time.
Thus, the unwanted gas such as 2 should be substantially
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WO ga/~osg3 pcr/Ausl/oools
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excluded from the packaging until restoration o~ the colour is
required. The method also enables a lid larger than the base
to be applied so the overhang of the lid can be gripped to
permit peeling of the lid off the base to allow a gas such as
5 2 to then permeate the remaining inner skin lid to attempt to
restore the original colour.
Objects and Statement of Invention
Accordingly, it is an object of the present
invention to provide improved methods for producing such
10 packaging.
Therefore in accordance with a first broad aspect of
the present invention there may be provided a method of
packaging goods comprising providing a base,
placing goods over said base,
placing an inner skin lid over said goods,
placing an outer lid ~ver said inner skin lid,
sealing said inner skin lid to said base in at least
partial skin packing relation to said goods to hold said goods
to said base,
causing said inner skin lid to be urged relatively
towards the under surface of said outer lid to displace
unwanted gas by reducing gas pressure therebetween,
and thereafter,
sealing said outer lid relative to said inner skin
25 lid and said base whilst in the urged condition, said inner
skin lid being of a material to allow a required gas to
pe~meate said inner skin lid when said outer lid is removed,
ruptured or opened, ~,
said base and said outer lid being of material which
30 will substantially inhibit undersired gas to contact said
goods.
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WO 9l/10593 PCT/AU9l/000
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Most preferably, the method also involves
introducing a desired gas between said inner skin lid and said
outer lid prior to sealing said outer lid relative to said
inner skin lid so there is a space therebetween which contains
5 said desired gas,
sealing said outer lid relative to said inner skin
lid and said base.
Most preferably said outer lid is sealed over said
inner skin lid so said outer lid is removable or is openable
10 without rupturing of said inner skin lid to allow a further
desired gas to permeate said inner skin lid and contact said
goods.
Most preferably the outer lid overhangs the
outermost periphery of said base and said inner skin lid to
15 permit easy gripping for subsequent peeling off of said outer
lid.
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Brief Description o the Drawings
In order that the invention can be more clearly
ascertained examples of preferred embodiments will now be
20 described with reference to the accompanying drawings ~;
wherein:-
Figure 1 is a side cross-sectional view of one
example of packaging in accordance with the present invention;
Figure 2 is a side cross-sectional view of a known
25 pre-pack skin packaging station used in a method in accordance
with the present invéntion:
Figure 3 is a side cross-sectional view taken
through apparatus used for producing the packaging shown in
figure l;
Figure 4 is a side cross-sectional view of a third
example of packaging in accordance with the present invention; ~-
and
Figure 5 i~ a side cross-sectional view taken
through apparatus used for producing the packaging shown in
35 figure 4.
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NO 91/105g3 PCT/AU9l/00015
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Detailed Descriptlon of Preferred Embodiments
Referring firstly to figure 1, there is shown a
plastics material base 1 made from a substantially gas
impervious material such as PVC. The base 1 is generally
5 rectangular in configuration and has a generally cup-shaped
depression with a peripherally extending lip 3. Goods 5 are
placed over the base 1 so that they are received in the
cup-shaped depression. A lid 7 is applied over the base 1 and
is sealed completely around the peripheral lip 3 by a
10 continuous seal 9. The seal 9 may be effected by a heat
sealing process known in this art, such as by an impulse heat
sealing process. Typically the lid 7 can be of PVC or other
suitable plastics material. An inner flexible skin lid 11 is
provided between the lid 7 and the base 3. The inner skin lid
15 11 is produced from a highly flexible plastics material which
is selected to allow a desired gas to permeate said inner skin `
lid 11. The gas may assist in maintaining bacteria growth to a
minimum or may be a gas which will assist maintenance of an
original colour of the packaged goods. In the case of red
20 meats, it is known they will turn dark brown in time owing to
the depletion of oxygen from the blood. The original red
colour can be at least partially restored by exposing the meat
to oxygen. Thus, in one exampie, the inner skin lid 11 may be
pervious to oxygen. The lid 7 overhangs the periphery of the
25 base 1, preferably all the way around its perimeter to permit
peeling off from the base.
Thus, in the case of red meats which are packaged in
the packaging shown in figure 1, the base 1 and the lid 7 will
be substantially gas impervious. Thus, the contents of the
30 package will be subject to the gas environment therein which
can be chosen for its preservation of the meat. The meat
will, in time, turn dark brown. By removing the lid 7 by
grasping the overhang or by opening the lid 7 by providing-an
~aperture in the lid 7 or~by other means, the original red
35 colour of the meat can be at-least partially restored as a.
required gas such as oxygen in the atmosphere which will then
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WO~1/10593 PCT/AU91/00015
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contact be inner ~in lid ll and will then permeate the inner
skin lid ll and contac~ the goods 5. A typical example of a
plastics material for the inner skin lid ll is a low density
polyethylene. Other plastics material having the desired gas
5 barrier and/or permeability charactexistics may be employed as
would be apparent to a person skilled in the packaging arts.
In certain cases it may be necessary to provide multi-layered
webs of plastics material for each o~ the base l, the lid 7
and the inner skin lid ll in order to obtain the desired gas
l0 barrier properties and the desired gas permeability properties
whilst permitting all of the plastics materials to be bonded
to one another. In the case where the lid 7 is to be peeled
from the base l whilst leaving the inner skin lid ll intact,
it is particularly preferred that each of the base lj the lid
15 7 and the inner skin lid ll be made from multi-layered webs of
plastics materials. In this case, the necessary adhesion
between the base l and the inner skin lid ll, and the inner
skin lid ll and the lid 7 can be appropriately chosen to allow
easy separation of the lid 7. Suitable plastics materials are
20 as follows:- -
Base l ........ UPVC/adhesive/LDPE ;
Lid 7 ......... Nylon/adhesive/LDPE plus a ;
contaminant such as Suryln
(Trade Mark) ~ ~
The contaminant is blended in small quantities with ~'
the LDPE to reduce the resultant bonding qualities of lid 7.
Inner lid ll .. LDPE
.. : . .
Typically the base l is of a thickness from about 50
microns to l000 microns. Thus, the base l can be
30 substantially ri~id. If desired the base l may be
manufactured rom a multi-layer material including a barrier
layer and a foamed polystyrene layer and accordingly it may
have a thickness of about l000 to 3000 microns. ;The inner
skin lid ll may have a thickness from l0 to l00 microns. ;The
35 lid 7 may have a thickness of between about 20 microns to l000
microns. Thus, the lid 7 may be substantially rigid also. If ~
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WO91/]0593 PCT/AU91/00~1
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- desired, the lid 7 may be manufactured from a multi-layer
foamed polystyrene with a barrier layer or from other cheap
plastics such as recycled polyester. It should be appreciated
that the lid 7 is not normally exposed to a purchasing
5 consumer. In practice the package will be supplied to a
retail outlet and stored until required to be displayed on
sales shelves. When the product is to be displayed, the lid 7
can be removed or opened or punctured to allow the necessary
gas to then permeate the inner skin lid ll. Thus, under
lO certain conditions the lid 7 will not be seen by the
purchasing public.
The above examples of plastics materials and their
thickness ranges is not to be considered exhaustive but merely
exemplary of certain plastics and the thickness ranges which
15 are suitable.
In the embodiment of figure l, it can be seen that
the goods 5 are firmly contacted by the inner skin lid ll and
that the inner skin lid ll closely follows the contour of the
lid 7. In practice it is proposed that in this embodiment the
20 lid 7 and the inner skin lid ll be in close contact so it will
appear that there is only a single lid. It is to be noted
that the seal 9 is substantially uniform in width through the
lid 7, the inner skin lid ll and the lip 3. Thus, when the
lid 7 is removed from the base l by peeling it therefrom, the `
25 peeling action will not rupture the inner skin lid ll which is
of relatively thinner and weaker plastics material than that
of the lid 7 or the base 3. This is because the interface
between the adjacent layers of the lid 7, the inner skin~lid
ll and the base 3 at the seal 9 will permit the peeling action
30 whilst supporting that portion of the inner skin lid ll
forming the seal 9 by the relatively more rigid peripheral lip
3. In addition, the bonding of the seal 9 between the lid 7
and the inner skin lid ll is weaker than the bonding between
the inner skin lid Il and the base 3.
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WO91/10593 PCT/AU91/0001
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In the construction shown in figure l the packaying
holds the goods 5 firmly to the base l. Typically, the base
l, goods 5 and inner skin lid ll are formed as a pre-pack by
known skin packing te~hniques and outer lid 7 applied over the
5 pre-pack.
In the embodiment shown in figure 2 there is shown a
typical skin packaging apparatus for producing skin packed
goods. Here there is provided a lower chamber 2 and an upper
chamber 4. The lower chamber 2 and the upper chamber 4 can be
lO closed and sealed together and gas, such as atmosphere,
evacuated from the closed chamber parts. A platen 6 within
the closed chamber parts 2 and 4 can then be lowered to enable ~ -
sealing of the inner skin lid ll to the base l with the goods
5 therebetween. It is noted that the goods 5 are above the
15 upper peripheral lip of the base l and thus there will be a
degree of stretching of the lid ll over the goods 5. An
electric heating strip 8 on the chamber part 2 extends
continuously around the package where a seal is required
between the base l and the lid ll. When the platen:6 is
20 lowered the heat.ing strip 8 can be electrically activated so
that there will be heat sealing and bonding of the inner skin -~
lid ll to the base l. When the chamber parts 2 and 4 are `~;
opened, atmospheric pressure causes the inner skin lid ll to
tightly urge on to the goods 5 and at least partially skin
25 pack the goods 5 to the base l. Thus, the goods 5 will be
held tightly to the base l. I desired, before sealing of the
inner skin lid ll to the base l, a desired gas can be
introduced into the closed chamber parts 2 and 4 to replace
atmospheric gas so that a desired gas will be retained between
30 the base l and the inner skin lid ll. This gas should be at a
pressure less than atmospheric so that when the chamber parts
2 and 4, are opened the inner skin lid ll will at least
partially skin pack the goods 5 to the base l so that the
goods 5 cannot move around on the base l. Such apparatus is
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- ~O9l/10593 PCr/AU91/0001;
g
considered well known in the packaging arts. The inner skin
lid 11 may be preheated by means not shown to assist in the
pa~tial skin packing.
Referring now to figure 3, there is shown apparatus
5 for producing the packaging of figure 1. The apparatus has a
lower chamber part 13 and an upper chamber part 15. The lower
chamber part 13 has a cavity 17 of a size to neatly receive a
pre-pack base 1 and inner skin lid 11. The upper chamber part
15 has a cavity 19 in which is provided a movable intermediate
10 chamber part 21. The upper and lower chamber parts 13 and 15
are relatively movable towards and away from each other to
effect opening and closing and to permi~ insertion and removal
of the lid 7, and the pre-pack base 1 and inner skin lid 11. . . .
Each of the lower, upper and intermediate chamber parts 13, 15
15 and 21 is movable by suitable rams or air bag mean~ known in
the packaging art. Accordingly, details have not been shown.
It is to be noted that the lower chamber part 13 has .
a forward face 23 whilst the upper chamber part has a forward
face 25 which sealingly mates with forward face 23.: The
20 intermediate chamber part 21 has a forward face 27 which mates :
with forward face 23.
In use of the apparatus, a pre-pack base 1 and inner
skin lid 11 is provided in the cavity 17 in the lower chamber
part 13. Optional heating means (not shown) can be provided
25 to heat inner skin lid 11 to a suitable processing
temperature. The outer lid 7 is then placed over the inner ~
skin lid 11 and each assumes the positions as shown. Suitable : `
guide pins (not shown) or other means (not shown) can be used ~.
to hold the packaging components in the desired positions. . :
30 The upper and lower chamber parts 13 and 15 are then closed..or
at least partially closed. The intermediate chamber part 21 ~ :
is then brought down towards a fully closed position with the
lower chamber part 13 but not to a sealing position where the
outer lid 7,-will be held sealed closed.with the-inner skin
35 lid 11. Air is-then exhausted through.air exhaust..29 to a ~-
pressure less than that under the inner skin lid 11 in the
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WO91/10593 PCT/AU91/00015
-- 10 -- ,
pre-pack. This, in turn, will cause the flexible inner skin
lid 11 to expand radially outwardly and push against the
innermost surface of outer lid 7 to, in turn, push outer lid 7
against the under surface 31 of the intermediate chamber part
5 21. This is because there will be a greater gas pressure
within the package than in the chamber causing that gas to
expand. The expansion of the inner skin lid 11 in this manner
will displace substantially all the air or gas such as 2
between the inner skin lid 11 and the outer lid 7 thus,
10 effecting close mating relationship of the inner skin lid 11
with the outer lid 7. The heating of the inner skin lid 11 by
the heating means (not shown) to a temperature for processing
will assist in the inner skin 11 moving in this manner.
The expansion of the inner skin lid 11 to the outer
15 lid 7 is limited by the shape and size of the undersurface 31
of the intermediate chamber part 21. Thus, good control can
be achieved over the ~xpansion and movement of the outer lid 7
and inner skin lid 11 by appropriate shaping of undersurface
31.
Desirably, the outer lid 7 is sized to neatly fit
over the inner skin lid 11 so that the goods 5 are still at
least partially held to base 1 during this outer expansion.
The undersurface of the intermediate chamber part 21 is
thereto sized and spaced from the lower chamber part 13 to
25 privde this result. ;~
Follow~g the exhausting of gas from air exhaust 29,
then the intermediate chamber part 21 is relatively moved with
lower chamber part 13 to effect sealing of the outer lid 7 to
inner skin lid 11 to the lip 3 of the base 1. An electric
30 heat impulse sealing strip 35 of known construction is
providèd in the lower chamber part 13 and, extends
continuously around the Iip 3 so that when activated it can
effect such sealing. Pressure is maintained between the- `
-intermediate chamber part 21 and the--lower chamber part l3
35 during'the sealing-process. In-the embodiment shown this seal
coincides with the seal on the pre-pack.
2~ 253
.VO 91/10593 ~ PCT/AU91/0001;
Seal means 37 are shown in the lower chamber part 13
and upper chamber part 15 to effect good air or gas sealing
between the lower chamber part 13 and upper chamber part 15
when this is required. The seal means 37 can be a rubber-like
5 material which extends peripherally around the forward faces -
25 and 23 of the respective upper chamber part 15 and lower
chamber part 13.
Following the sealing of the outer lid 7 to the
inner skin lid 11 to the base 1, the upper chamber part 15,
10 lower chamber part 13 and intermediate chamber part 21 can be
opened so that the packaging will be exposed to atmospheric
pressure. The outer lid 7 and the inner skin lid 11 will then
collapse slightly under atmospheric pressure and thereby
tightly hold the goods 5 to the base 1 within the packaging.
15 The packaging can then be removed from the chamber parts 13,
15 and 21.
It should be noted that the inner skin lid 11 is
sheet like - without openings or holes - so it can be skin
wrapped over goods 5 on the base 1, and so it can, inturn, be
20 inflated up against the undersurface of outer lid 7. Thus,
whilst the inner skin lid 7 is gas permeable, it is only gas
permeable over an extended period of time, and it is not
freely gas permeable to the extent as could be experienced
with a gauze or mesh like web~
The outer lid 7 can then, if required, be subject to
heat to relieve any thPrmal or other stress therein caused by
the packaging proaess.
Typically a machine could be provided which
manufactures packing of the type disclosed by producing the
30 packaging in a continuous elongate web. In this connection
there would be first elongate web in which bases 1 are
provided, a ~urther elongate web from which inner skin lids 11
are provided as pre-packs, and a further elongate web from
which lids 7 are provided. When the packaging exlts from the
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W091/10593 PCT/AU91/000l~
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chamber parts 13, 15 and 31, the individual packages can be
cut from the continuous elongate webs of packaging material by
a suitable cutting means.
In use, the outer lid 7 can be peeled from the base
5 1 whilst leaving the inner skin lid 11 intact and sealed to
the base 1 around the seal 9. The required gas for red meats,
such as 2 in normal atmosphere, can then permeate the inner
skin lid 11 to contact the meat. The remaining pre-pack
comprising the base 1 and the inner skin lid 11 represents a
10 pleasing package to an intending purchaser. Suitable
advertising material may be printed on either or both of the
base 1 or the inner skin lid 11. Typically, the inner skin
lid 11 is of a clear transparent material so the contents can
be viewed easily.
Referring now to figure 4 there is shown a variation
of the packaging shown in figure 1 where like components have
the same numerical designations. In this embodiment the
packaging is produced in the same manner as in the previous
embodiment but before sealing of lid 7 to the base a desired -
20 gas is provided in a space 39 which is then produced between
the outer lid 7 and the inner skin lid 11. In other words,
substantially all the gas between inner skin 11 and outer lid ;
7 is excluded by expansion of the inner skin lid 11 to the
undersurface of outer lid 7 as described and then a desired
~5 gas is forced between the inner skin 11 and outer lid 7. The
desired gas can permeate the inner skin lid 11 to contact the
goods to enhance preservation. The inflation of outer lid 7 -
relative to inner skin lid 11 with such gas will assist in
providing shock absorption properties to the package to
30 inhibit against rupture of outer lid 7, particularly when a
large number of such packages are carted in stacks or -
packages.
In this embodiment the gas provided in the space 39
can be provided by means of plate means- which forms a gas
35 flushing member of the type disclosed in the aforementioned -
U.S. specification 4,685,274. In this case the gas flushing
h l~ S L,~
WO 9l/10593 PCT/AU91/0~1;
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me~ber will be placed between the outer lid 7 and the inner
skin lid 11 and so that the ~orward face 27 on the
intermediate chamber part 21 can pass between a central
opening in the gas flushing member to effect sealing by the
5 impulse sealing strip 35. A diagrammatic sketch of the gas
flushing member is shown in figure 5 in combination with the
chamber parts 13, 15 and 21 shown in fiqure 3. In this
embodiment the gas flushing member is shown by numeral 41 and
comprises a plate with a rectangular shaped central opening 43
10 which corresponds to the shape of the required package. The
gas flushing member 41 has a chamber 45 through which a
desired gas can be emitted to pass through a gas outlet
opening 47 . Thus, when the upper chamber part 15 and lower
chamber 13 close-they close on the faces of the gas flushing
15 member 41. When the intermediate chamber part 21 closes on ~ -
the lower chamber part 13 it passes through the opening 43.
The gas which is passed through the opening 47 is then -
provided between the inner skin lid 11 and the outer lid 7.
When sealing takes place on closing of the intermediate
20 chamber part 21 with the lower chamber part 13 the gas whic~ `
has passed through the opening 47 is then sealed in the space
39 between the outer lid 7 and the lid 11. This desired gas
can be chosen for permeating the inner skin lid 11 with time
for enhancing preservation of the goods. Typically the gas
25 can be N2 or other known gas or gases which can enhance
keeping of the red meat. The gas should be at a pressure
greater than the pressure under inner skin lid 11 so inner
skin lid 11 will be urged thereby into at least partial skin
packing relation with the goods 5. Desirably the gas is at a
30 pressure slightly less than atmosphere pressure.
Modifications may be made to the present invention
as would be aparent to persons skilled in the packaging art. `~
These and other modifications may be made without departing
from the ambit of the invention, the nature of which is to be
35 determined from the foregoing description.
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