Note: Descriptions are shown in the official language in which they were submitted.
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PACKAGE AND PACKAGING METHOD
TECHNICAL FIELD
This invention relates to a packaging method and package, and in
particular a package for free-flowing material such as powder, granulated
material or larger particulate material.
BACKGROUND ART
The nature of the method and package of this invention make it
applicable to the packaging of a free-flowing material. The term "free-
flowing material" is used hereinafter to include any solid material in a free-
flowing form, from fine powders to granular material, to larger particulate
material such as tablets, capsules, nuts, sweets, and the like. However, it
will be appreciated that the invention is primarily directed at the packaging
of
products for which vacuum packaging is necessary or desirable for hygiene
and product preservation reasons and/or to facilitate packaging in a form
suitable for bulk transportation.
There are many products which need to be packaged in a substantially
sealed environment. In the process of such packaging, air or an inert gas
employed during the packaging process may be trapped with the product-in
the sealed package. This is particularly the case with the packaging of free-
flowing material, such as milk powders, flour, pigments, cement and the like,
and also with packaging at high speed.
Trapped air or gas in a sealed flexible package causes difficulties when
a plurality of packages are stacked for storage or transportation purposes.
One problem is the instability which the trapped air or gas creates in the
stacked packages. A secondary problem is the risk of bursting of packages
under compression. A third problem is possible oxidation of product.
In addition, any trapped air or gas adds to the volume of a package
which adds to the cost of transportation where that cost is measured by
volume rather than weight.
Packages made of paper~may provide the required permeability to allow
the escape of trapped air or gases, but they do not provide the protection
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from contamination required with certain products such as milk powders, flour
and other food products. They are also vulnerable to damage through
moisture or extremes of temperature.
Composite packages involving two or more layers of different
materials, including paper and plastics have been employed, but such
composite packages can be costly to produce and dispose of.
Valved plastic bags are also known in which the package is filled with
a powder or granulated product through a valve sealed in a side of the
package. However, air or gases may still be sealed in the package once the
valve is closed.
A further known method of dealing with trapped air or gases in
packages has been to provide perforations through parts of the package walls.
Unfortunately, however, perforations provide the opportunity for
contamination, and may only be suitable for solid or granular product which
will not escape through or block the perforations.
Milk powder is an example of a product generally packaged in high
volumes and therefore requires fast and efficient packaging.
Using conventional methods, milk powder, for example, is packaged in
flexible bags. Typically, these bags are made of at least two layers, an
external layer of craft paper (which may in fact be 3 or 4-ply) and an
internal
layer of a plastics material. The loose milk powder in such a package has a
relatively low density in view of the quantity of air trapped in the bags.
Thus,
considerable space is taken up in shipping containers and other transport
media when the packaged milk powder is transported. This leads to
considerable cost in freight charges. Understandably, these costs reflect
adversely on the economics of exporting milk powder.
Again because of the relatively low density of the packaged product,
and inappropriate shaping of the containers, the conventional bags or
containers once packed are not rigid which means that they cannot be
efficiently stacked together for transportation:
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Furthermore, in conventional packages the inner plastics layer is
generally bonded in some way to the outer paper layer or layers. This results
in problems in recycling of used packages, and such packages may not be
approved by regulatory bodies in some countries.
There is also a perception that paper is less hygienic than plastics
material, having a negative influence on potential buyers of product packaged
in packages having a paper outer covering.
From a marketing point of view, it is also a negative factor with
conventional packaging that the packages are generally of a non-uniform
shape, resulting in poor presentation of the product, difficulties in
handling,
and possible difficulties in clear labelling.
Another particular problem associated with the packaging of milk
powder is that it is an extremely dusty product and this creates difficulties
in
thermoforming and vacuum sealing of packages containing milk powder.
Thus, it is an object of the present invention to provide a package and
a method of packaging to reduce or overcome at least some of the
abovementioned problems, or to at least provide the public with a useful
alternative.
Other objects of the present invention may become apparent from the
following description which is given by way of example only.
DISCLOSURE OF INVENTION
According to one aspect of the present invention there is provided a
method of packaging a free-flowing material, said method including the steps
of:
- filling or partially filling a first container with a free-flowing
material, said first container of substantially impermeable material
but having at least one gas-permeable portion seaiingly engaged or
integrally formed with the substantially impermeable portion;
- closing said first container;
- applying a vacuum to the first container through said one or more
gas-permeable portions; and
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- sealing said first container.
In one preferred form, the first container may be sealed by the
application of closure means over the or each gas-permeable portion.
Alternatively, or additionally, the first container may be sealed by being
sealed within a second container of substantially impermeable material.
In a preferred form, the vacuum may be applied to the second
container before sealing.
Alternatively, the vacuum may be applied in two stages, first to the
first container through the one or more gas-permeable portions, and
subsequently to the second container, with the first container enclosed, prior
to sealing of the second container.
In a further preferred form, the method may further include the step of
positioning the first container in a forming box prior to filling, to enable
form
filling.
According to a further aspect of the present invention, there is -
provided a package of free-flowing material under vacuum, said package
including a first container predominantly of a substantially impermeable
material but having at least one gas-permeable portion sealingly engaged or
integrally formed with said substantially impermeable material, and closure
means adapted to seal the or each gas-permeable portion and retain a vacuum
within the package.
In one preferred form, the closure means may include one or more
stickers of substantially impermeable material sealingly engaged over the or
each gas-permeable portion.
Alternatively, or in addition, the closure means may include a second
container of substantially impermeable material about said first container,
and
sealing the vacuum within the package.
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In one preferred form, the package may include a first vacuum in the
first container, sealed by the application of one or more stickers of
substantially impermeable material sealingly engaged over the or each gas-
' permeable portion, and a separate vacuum retained in the second container.
' In a preferred form of package, the or each gas-permeable portion may
comprise a longitudinal strip or patch of gas-permeable material, sealed at
its
edges to the substantially impermeable material.
Other aspects of the present invention may become apparent from the
following description which is given by way of example only and with
reference to the accompanying drawings in which:
BRIEF DESCRIPTION OF DRAWINGS
Fi4ure 1:
Shows a perspective view of a package of the present invention, cut
away in one corner;
Fi4ure 2:
Shows a perspective view of an inner container of the present
invention in one form;
Figures 3A - 3C: -
Show perspective views of alternative embodiments of an inner
container of the present invention;
FiQUres 4A - 4C:
Show diagrammatic cross-sectional views of a packaging method used
in one embodiment of the present invention.
Fi4ures 5 - 9
Show schematic diagrams of apparatus of the present invention, in one
preferred embodiment, employed in the production of a package of the
invention.
DETAILED DESCRIPTION OF INVENTION
With reference to Figure 1, a package 1 of the present invention in one
embodiment comprises an inner container 2 and an outer container 3, the
inner container 2 having a gas permeable portion 4 and a substantially
impermeable portion 5. Ends 6 of the inner container and ends 7 of the outer
container are sealed, a vacuum having been applied to the outer container 3
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prior to sealing of one end of that container. It will be appreciated that the
seals on the outer container may be oriented differently, for example
longitudinally on one or both sides or faces of the package, depending on the
method of sealing the outer container employed.
With reference to Figures 2 and 3, the majority of the inner container 2
is of the substantially impermeable material, for example an impermeable,
flexible plastics material, such as 60 micron gas barrier plastic. The gas
permeable portion 4 may be in the form of a longitudinal strip, as in Figure
2,
in the form of a patch or patches, as in Figures 3B, 3C., or in the form of a
block section, as in Figure 3A. It will be appreciated that these are but
examples of the positioning of the gas permeable portion, an important factor
being that in production of the package at least a part of the gas permeable
portion will be adjacent the site of application of the vacuum.
From the point of view of convenience of manufacture, it will be
appreciated that the embodiment of the inner container 2 of Figure 2 may be
produced from a tube of material having a longitudinal strip of the gas
permeable material sealed to the substantially impermeable material along its
edges 8. Similarly, the embodiments of Figure 3B, 3C may also be formed
from tubular material with the gas permeable portions comprising patches-
sealingly engaged in or over punched out portions of the substantially
impermeable material at intervals along the length of the tube, determined
according to the size of the packages required.
The gas permeable portion of the inner container 2 has properties
enabling the applied vacuum to be transferred to the inner part of the inner
container 2, whilst prohibiting the transfer of any material contents from the
inner container 2 to the outer container 3. In addition, the gas-permeable
portion will preclude the passage of micro-organisms into the first container.
Ideally, it or they would allow the efflux but riot the influx of air or gas.
Without intending to limit the scope of the term permeable material, examples
may include gas-permeable plastics, paper or textile.
The degree of permabil'rty of the gas-permeable portion or. portions will
be dependent on the nature of the substantially impermeable portion, the type
of sealing employed and the nature of the product packaged.
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The impermeable and permeable portions may be sealed together by
welding, and each portion is therefore preferably made from a thermoplastics
material.
In an alternative embodiment, an inner container of the present
invention may be formed from laminated layers of plastics material, one or
more layers omitted in at least parts of the package to provide the gas-
permeable portion or portions. In such an embodiment, the substantially
impermeable and gas-permeable portions would be integrally formed rather
than sealed together.
A package 1 of the present invention may have a preformed shape, for
example a brick-shape to facilitate bulk packaging. It will be appreciated
that
the shaping of a package may be achieved by shaping of the inner 2 and/or
outer container 3, for example, by thermoforming or through the application of
pressure.
The outer container 3 may be made of any material that is gas
impermeable so as to retain the vacuum applied. It is preferably a material
which is structurally strong and yet flexible, such as a plastics material, so
as
to provide protection for the inner container 2. The material of the outer-
container may include some material such as nylon to enhance the strength.
It may also include mylar as a gas barrier. And it may optionally be of a
material, or it may include a barrier layer, which protects photosensitive
product, for example it may include a UV barrier.
It will be appreciated that no sealing is required between the inner
container 2 and the outer container 3. Thus, the outer container may be
easily pealed off the inner container, for simple recycling or disposal. Once
the product has been removed from the inner container, then that too can be
separately recycled or disposed of.
In the above description, reference is made to the vacuum being
applied within the outer container, and being transferred through to the inner
container via the gas-permeable portion or portions. For some products, and
particularly where hygiene requirements are stringent, it is envisaged that
the
gas-permeable portion or portions of the inner container may themselves be
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sealed prior to the inner container being placed in the outer container. Thus,
a
vacuum may be applied to the inner container, a sticker or the like sealingly
engaged over the or each gas-permeable portion, and the vacuum-sealed inner
container than subsequently vacuum sealed within the outer container. With
this configuration, the outer container may be stripped off the product_and
disposed of without interfering with the integrity of the product in the inner
container.
The packages described above, when formed and vacuum-packed, for
example, in a rectilinear block, are more conveniently and efficiently
transportable, since the volume of packaged product is reduced and the
stability of stacked packages is increased.
For some products, for example, those for which there are no hygiene
issues, or less stringent hygiene issues, inner containers alone, in
particular
embodiments, may be suitable for packaging. In such packaging, the gas-
permeable portion or portions are configured in such a way that when a
plurality of the packages are stacked one on top of the other, any air or gas
trapped in a package can escape through the gas-permeable portion or
portions, thus facilitating the stability of a stack of packages. The gas-
permeable portions would preferably be a longitudinal strip or strips
extending
over the ends of a package (as in Figure 2j, a patch or patches at the ends of
the package (as in Figure 3B) or strips or patches on the sides of the
package.
fn such configurations, at least a part of the gas-permeable portion or
portions
are clear of any surface of the package which forms a contact surface with
adjacent packages in a stack of packages.
It will be appreciated that a package in this form, when closed, is
secure from contamination by micro-organisms, whilst the gas-permeable
portion enables the elimination of air or gas under pressure without breaking
the package seal or seals, or the weld between the substantially impermeable
and gas-permeable portions.
A package of the present invention has particular application in the
packaging of powdered materials, such as milk powder, protein concentrates,
pharmaceutical products, alum, fertilisers and the like, where there can be a
substantial amount of air trapped in the product during packaging. However,
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these packages will also have potential application for the packaging of other
granulated or solids material, where there is a likelihood of air or gas being
trapped in the package during packaging.
The method of producing packages according to the present invention
will now be described, by way of examples, with reference to the
embodiments shown in the Figures.
Example 1
Two rolls of tubular material are provided. The first roll is for
forming the inner container 2, and comprises mainly impermeable
material with a longitudinal strip or patches of gas permeable material.
The second roll is of impermeable material and is for forming the outer
container. It will be appreciated that the tubular material for the inner
container may be preformed, or separate rolls of the gas permeable and
impermeable materials may be sealed together to form the tube in the
packaging machine itself.
A first end of a length of tubular material for the first roll is
sealed and the product to be packaged is fed in to the open inner -
container, for example through a conventional hopper-type feed. The
second end of the inner container is then sealed. The closed inner
container is then positioned in a length of the tubular impermeable
material from the second roll, one end of which is sealed. The second
end of the outer container 3 is then closed about a snorkel and a
vacuum is applied causing the walls of the outer container and the
inner container to contact one another, and drawing a vacuum on the
inner container through at least a part of the gas permeable portion
adjacent the point of application of the vacuum. The second end of
the outer container 3 is then sealed.
It will be appreciated that the package may have a preformed
shape defined by preformed shaping of the inner and/or outer
container, or it may be shaped during the packaging and vacuuming
process.
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Example 2
Referring to Figure 4, an alternative method of applying the
outer container 3 may be by thermoforming. The application of
thermoforming enables the use in some embodiments of an easy-peel
layer on the external packaging of the milk powder.
In this embodiment standard thermoforming machinery may be
set up with a bottom layer of gas impermeable film in a standard
thermoforming cavity. The filled and closed inner container is placed
into this thermoforming cavity. The cavity is then indexed to a
thermoforming hood in order to apply a vacuum to the inner container
and provide a sealed gas impermeable outer container.
Figure 4A illustrates the first stage in the thermoforming
process. In this stage an inner container 11 filled with product 12 is
placed into a thermoforming cavity 13. The cavity 13 is lined with a
gas impermeable plastics layer 14. The cavity 13 is then indexed
forward to where a thermoforming hood 15 (see Figure 4B) is
positioned. At this stage a vacuum is applied to the cavity 13 causing
air to leave the contents 12 of the inner container 11, via the gas -
permeable portion or portions (not shown).
This application of a vacuum also causes the inner container 1 1
to settle below the top of the cavity 13, to form a substantially block-
like shape (see Figure 4C).
Examale 3
This Example is described with reference to Figures 5 to 9.
Referring to Figure 5, a web of material 51 from which the inner
container is formed is opened up and the end cuffed over an open end
53 of a forming box 52. Means 66 are provided to separate a sealed
end of the inner container 54 from the rest of the web 51.
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A blow/suck operation, employing an air inletloutlet 55, is used
to first inflate and then invert the inner container 54 into the forming
box 52.
Moving to Figure 6, the forming box 52 is then rotated to a
' vertical position, and the product to be packaged is introduced to the
inner container 54 via hopper 56. The cuff 64 of the inner container
54 is then released and this end of the inner container 54 is sealed by
sealing means 67.
Turning to Figures 7 and 8, the forming box 52 is rotated to the
horizontal and supported by carriage 59. A lid 65, which may form
part of the carriage, is closed over the open end 53 of the forming box
52 (see Figure 8).
One side 57 of the forming box 52 includes slots or perforations
(not shown) at a central part. This side 57 now forms an upper
surface of the forming box 52. The inner container 54 within the
forming box 52 is configured such that the permeable portion or
portions are on the side of the inner container 54 adjacent this side 57
of the forming box 52.
With the closed forming box 52 supported by carriage 59, rams
60 are positioned above side 57 of the forming box 52. This side 57 is
a false side, moveable in and out, such that the thickness of the
forming box 52 may be reduced by the application of pressure to this
side 57.
The forming box 52, with its inner container 54 and contents, is
subjected to vibration on the carriage 59 and pressure from the rams
60 to expel air and form the shape of the inner container 54 within the
forming box 52. A vacuum is then applied through the
slotted/perforated central part of the side 57 of the forming box 52,
drawing any remaining air or gases from the inner container 54 through
the gas-permeable portion or portions.
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With reference to Figure 9, the lid 65 then removed and the
formed inner container 61 is removed from the forming box 52.
As the formed inner container 61 is removed, a sticker or
stickers may be applied over the or each gas-permeable portion_to sea!
the inner container. Alternatively, the formed inner container 61 may
be transported to the outer container sealing apparatus 62 via suction
means (e.g. one or more suction cups) which continue to apply a
vacuum to the inner container via the gas-permeable portion or
portions.
The formed inner container 61 is then positioned in an outer
container 68 of substantially impermeable material, a snorkel 63
inserted into the outer container 68, a vacuum is applied to the outer
container 68 and this container is then sealed.
Alternatively, the outer container may be applied by flow
wrapping, with a vacuum applied within the outer container during the
flow wrapping process.
It will be appreciated that this example differs from example 2,
primarily in that the primary shape of the package is formed on the
inner container rather than the outer container. It also differs in the
optional application of a sticker or stickers over the gas-permeable
portions) to provide for additional sealing of the product in the package
as a whole. '
It will be appreciated that the method and package of the present
invention has particular application in the packaging of powdered materials
such as milk powder, protein concentrates, pharmaceutical products, alum,
fertilisers and the like, although it also has potential application for other
free-
flowing solids material such as granular material.
Thus, the method and package of the present invention provides an
efficient means for packaging of powder or granulated products. The
application of a vacuum substantially increases the density of the contents of
the inner container resulting in a reduced volume of the packaged products
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and a more conveniently shaped package for easier handling, stacking and
bulk transportation, thus providing the opportunity to considerably reduce
freight costs:
Since the inner and outer containers are readily separable, recycling of
' the packaging material is facilitated. The use of an outer layer of plastics
material improves the mechanical strength and hygiene of the pack in
comparison with packages employing an outer layer of paper. Furthermore,
because of the substantially rigid form, and regular size and shape of
packages of the present invention, printing and labelling is facilitated, with
the
result that package presentation is improved.
Where in the foregoing description reference has been made to
specific components or integers of the invention having known equivalents
then such equivalents are herein incorporated as if individually set forth.
Although this invention has been described by way of example and
with reference to possible embodiments thereof it is to be understood that
modifications or improvements may be made thereto without departing from
the scope or spirit of the invention, as defined in the following claims.
