Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THF INYENTION
This invention relates generally to the art of packaging and
more particularly to the art of producing a package by forming a pocket
in a sheet of wrapping material, placing a product in the pocket, and
sealing the material to enclose the product.
Various methods have heretofore been used for forming packages.
The one commonly used method requires prefabricated, heat shrinkable
bags or pouches and a filling operation which is followed by subsequent
evacuating, closing of the bag and then shrinking the bag about the
product if desired.
U. S. Patent No. 3,956,867 to Kastulus Utz et al describes the
formation of a shrinkable pouch in a first foil, putting the co~modity
to be packed into the space between the pouch and a second foil, sealing
both foils together and shrinking the first foil in the area of the
pouch.
Another method known in the art as skin packaging is shown in
U. S. Patent No. 3,736,721 issued to Robert 0. Wolfelsperger which shows
a film drawn into a cavity and held there while the product is placed in
the film cavity after which the cavity is evacuated and the vacuum
released so that the single sheet collapses around the product making a
peripheral seal.
Various approaches have been taken in an attempt to provide
improved methods for producing display packages. ~ne of the better
known is a blister type package, for example, U. S. Patent No. 3,776,375
to Howard A. Rohdin wh;ch shows preforming a blister enclosure from a
un;tary p;ece of plastic sheet material by forming the enclosure in two
opposed mating sections integrally joined along a fold line which traverses
the base portion. Flanges are formed along the free edges of each of
the two sections to provide means for securing them together around the
product to be packaged.
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~he present invention provides a new process and package in
which the advantages o~ skin, bubble, and bag packaging are incorporated
into a single package. With this invention the simplicity and economics
are even greater than those of skin packaging. As in bubble packaging
and bag packaging the present packaging method can be employed w;thout
first making a substantial investment in packaging eguipment. In addition,
th;s process produces a package in which the prsduct may selectively
project from znd be visible from either one or all sides of the finished
package and yet be covered completely by a protective pocket of plastic
D film.
SUMMARY OF THE INYEN~ION
In one aspect of the present invention, a product or artîcl,~
or a plurality of products or ar$;cles are enclosed in a wrapping material;
e.g., therm~plastic film or paper, by the steps which comprise forming a
S pocket or cavity in a sheet of the material, placing a product in the
pocket, folding the resultant flange portions of the sheet so that the
flange portions ~f the film sheets are in a face-to-face relationship9
and bond7ng at least portions of the flanges together. In another
embodiment the pocket may be evacuated prior to completing the seal.
' Another aspect of the invention comprises fonming a heat
shrinkable pocket and then subsequent to evacuating the pocket, shrinking
the pocket about the product.
In another aspect, the present invent;on provides a package
having a product or article enclosed within a thermoplastic film which
tightly conforms to the shape of the product and which film is seamless
for at least one half of the periphery of the product, the film extending
beyond the periphery of a portion of the product to form an extension or
flange of twc layers of film bonded together.
Still another aspect of the invention comprises forming a
3n means on the package for displaying the packaged product.
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The invention may be better understood by reference to the
drawings described below and the following description.
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BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which are appended hereto and ~ade a part of
this disc70sure:
Figure 1 is a diagrammatic representation of a preferred
embodiment of the process of this invention; and
Figures 2a, 2b, and 2c are top plan views illustrating the
step by step formation of the package,
Figures 3a, 3b and 3c are corresponding side views of Figures
2a, 2b and 2c respectively;
Figure 4 is a view in perspective of a package constructed in
accordance with this invention.
DETAILED DESCRIPTION
Figure 1 schematically illustrates the process steps of producing
an evacuated package. A web 2 of a sheet of wrapping material; e.g~,
paper but preferably a flexible thermoplastic film, is advanced forward
from a supply roll 4, a pocket 6 is formed in the transversely center
portion of the material and pr:oduct 8 is placed in the formed pocket.
The pocket may be formed by any effective means; e.g., heat is appl;ed
and the center portion is stretched by positive or negative pressure to
form a pocket. The film forming the pocket may be heat shrinkable
provided the heat and degree of stretch are selected to cause orientation
in the film. One or more products or articles are then placed into the
pocket. The material is center hlded so that the flat flange portions
10 of the material surrounding the pocket are in a face-to-face relationship
and the sides of the sheet mater;al are bonded or heat sealed together
along seals 14. In many instances the top edges are also sealed.
However, if it is desirable to evacuate or gas flush the air fro~ the
~a package, it will preferably take place prior to sealing the top edge.
A simplified step of evacuating is illustrated using a continuous vacuum
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in chamber 16; howeYer, it is to be understood that any suitable means
for evacuating ~r gas flushing the pocket may be employed. If the film
of the pocket has been oriented and ;t is desired to shrink it, any
suitable means may be used including contact with hot air or hot water
for shrinking the pocket about the product or products when desired;
i.e., heat can be applied to the pocket inside the vacuum chamber 16
causing the stretched pocket to shrink about the product which can be
performed subsequent to evacuation or performed simultaneously with
evacuatiun. Further, for the sake of simplicity, the process is shown
drawing a sheet of material 2 horizontally forward from a supply roll 4
and after forminq and filling the pocket, folding the sheet upwardly so
that the flat portions of the sheet are in a face-to-face relationship7
heat sealing the sides together and evacuating the pocket through the
open top 18, closing the top with heat seal 20 and then shrinking the
pocket about the product. The successively formed packages may or may
not be subsequently severed from the continuous web of material. Illustrated
in Figure l, a cut is made to form an individual evacuated package 24.
As stated hereinbefore, Figures 2a through 2c (top view) and
corresponding Figures 3a through 3c (side view) show the forming stages
of a sheet of film to produce an evacuated package with a product contained
therein. Figures 2a and 3a show a product 8 in pocket 6 formed in a
sheet of film 2. Figures 2b and 3b illustrate the package with the flat
flange portions of the film in a face-to-face relationship with the
sides bonded together along seals 14. Figures 2c and 3c show an evacuated
package 24 with pocket 6 shrunk about product 8.
As shown in Figure 4" a package 24 with a product or article 8
contained in thermoplastic film which covers and tightly cnnforms to the
product. The film extends beyond the product, to form a flang2 or
extension 10 adjacent only a portion of the product.
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The heretofore described package can easily be a package for
displaying all sides of a product contained therein by using a transparent
wrapping material such as transparent thenmoplastic film. Further, by
bonding or sealing the sides and top of the flat, face-to-face portions
of the film a distance inwardly from the edges of the package to allow
for tabs 26 which are not bonded or sealed together provides a border
outside of the evacuated area for aperture or apertures 28 for hanging
the package to display the packaged product on one or all sides.
EXAMPLE s
The following example illustrates the method of packaging a
food product utilizing a laminated film. It has been found that the use
of a laminated sheet of film having a layer impermeable to oxygen, a
flexible film layer read;ly heat sealable and a third support layer has
been particularly advantageous in providing a shelf-stable food product.
However, in this respect, it should be understood that the following
example is merely illustrative of the present invention and should not
be construed as limited thereto.
A laminated film sheet as above described was clamped and heat
applied to the center portion thereof.The heated portion was vacuum
Formed to form an oriented pocket. The sheet of film was clamped so
that the inner surface of the pocket was the heat sealable layer. A
piece of meat was placed in the pocket, the sheet o~ film then centerfolded
so that the flat portions of the sheet were in a faee-to-face relationship
and sealed on two sides. The partially sealed package was then evacuated
through the opening at the top and a final top seal made to form a
hermetically sealed package. The pocket was shrunk tight to the product
by immersing the package in hot water thereby providing a package without
any folds or pleats which are potential problem areas since they are
locations which can present leakage and contamination problems.
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The principles of the present invention are not limited solely
to packaging food products, although due to the hermetic sealing conditions
readily established during packaging, the presenk method is particularly
adapted for food product packaging. However, any products or articles
may be packaged using the present method. Furthermore, the novel method
of the present invention can be employed for the fabrications of packages
with a wide variety of wrapping materials, including thermoplastic
polymeric materials Instead of heat sealing, the top and side edges
can be glued together with a suitable adhesive.
O Since it is obvious that various changes and modifications can
be made in the above-description without departing from the nature and
spirit thereof, this invention is not restricted thereto except as set
forth in the appended claims.
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