Note: Descriptions are shown in the official language in which they were submitted.
CA 02471233 2004-06-17
- 1 -
Technical Field
The present invention relates to method of
manufacturing a gas displacement package and a sealing
packaging container and the package.
Background Art
Hitherto, it is general that individual
households buy foodstuff and cook them to eat.
Recently, however, for the intention of effecting
housework simply, life style is increased in which
households buy food products, which are previously
cooked in a food processing room or a central kitchen
of a supermarket or the like, at supermarkets or
convenience stores to eat at home. In the cooked food
field, developments of not only contents but also
packages with various sizes or shapes have been greatly
effected in order to provide best displays by changing
shapes and designs of the packages.
Especially, in a deli field, unlike a
conventicnal sales manner in which one kind of food
product is sold in large quantity, food products cooked
by many cooking methods are divided into small portions
for more variation and sold so that consumers can
choose the products as desired. Thus, for clerks of
delis at supermarkets or convenience stores, it becomes
CA 02471233 2004-06-17
- 2 -
a problem that cumbersome and complication required for
changing devices at the time of packaging various kinds
of food products in small quantity, reduction in
production efficiency caused by the complicated
changing, and complicated control of packaging machine
parts for respective packages for various kinds of food
products in small quantity.
On the other hand, it is in trend that cooked
food products in which original flavors of ingredients
are utilized are desired, but food products with
reduced food additives soon become rotten and have
short product cycles. This causes problems of need of
many hands or reduction in a yield of food processing.
As a method of preserving products for a long
period, gas displacement packaging is known that
preserves food products under an inert gas atmosphere
to increase a distance of product distribution, reduce
products that have fallen out of date, and increase
production efficiency. As an example of such gas
displacement packaging, JP-A-9-295677 discloses a gas
filling packaging method in which a gas filling
packaging tray is used that includes a tray on which a
substance is placed and a lid that covers the tray, the
lid having a gas blow-in inlet on a top thereof and a
gas outlet therearound, to cover the entire tray with a
heat-shrinkable film having a gas barrier property.
This method allows gas to be blown in through the gas
inlet and exhausted through the outlet around the lid,
CA 02471233 2004-06-17
- 3 -
thus allowing air remaining in the tray covered by the
lid to be displaced by gas.
JP-A-4-189721 discloses a method in which
there is provided an insulating base plate having a
heating element at an edge of a hole opened in a plate,
a container is placed with a flange of the container
applied to the heating element, and then filled with
contents, subjected to gas displacement in a vacuum
chamber, and covered with a lid, and after conveyed by
a conveyer, a pressing plate is lowered from above the
container to perform heat bonding of the container and
the lid with a die of a heated seal device.
Further, JP-A-61-103 discloses a method in
which a container made of a synthetic resin sheet is
filled with contents, an opening of the container is
covered with a sealing film or sheet, and then the
entire opening of the container is thermally pressed
from an upper surface of the sealing film or sheet by a
heat roll to thermally bond a periphery of the opening.
However, the method represented by JP-A-9-
295677 is a method in which the gas is simply flushed
into the package through the gas blow-in inlet at the
top of the lid, and the air is exhausted through the
gas outlet, thus a rate of displacement when the gas
displaces the air in a space in the package is low, and
depending on shapes of the contents, oxygen contained
in the contents cannot be sometimes displaced by the
displacement gas. The entire package is covered with
CA 02471233 2004-06-17
- 4 -
the heat-shrinkable film having the gas barrier
property, thus cutouts of the gas blow-in inlet at the
top of the lid or the gas outlet tend to break the film
to cause leakage of the filled gas. Besides, because
of double packaging of the container and the film, the
number of packaging materials are lot, causing a
problem of increase in entrepreneur's bearing of cost
based on the Container and Package Recycling Law.
On the other hand, the gas displacement
method disclosed in JP-A-4-189721 requires the heat
element corresponding to each of various containers
with different sues or designs. This requires a seal
die resistant to pressure that accommodates changes in
atmospheric pressure in the chamber, and such a
dedicated seal die for each container is expensive to
manufacture.
The method disclosed in JP-A-61-103 causes
thermal deformation of the sealing film or sheet when
the sealing film c>r sheet is thermally pressed on the
opening of the container by the heat roll. When the
content protrudes beyond the depth of the container,
there are problems that the content is pressed by the
top film, or the films overlap to each other at flange
of the container to make wrinkles and cause foreign
matters to be mixed into through clearances. In
addition, like the above described example, this method
has a problem that, for containers with different
shapes, heating dies corresponding to the shapes have
CA 02471233 2004-06-17
- 5 -
to be provided.
The present invention has an object to
provide a method of manufacturing a gas displacement
package and a sealing package that allows air in a
space and a content in the package to be displaced by
gas at a high rate of displacement, complies with the
Container and Package Recycling Law, and facilitates
changes in shapes and sizes of the package.
Disclosure of the Invention
A method of manufacturing a gas displacement
package according to the present invention is
characterized in that a container comprises a
receptacle and a Lid, the receptacle and the lid are
overlapped each other at respective edge portions to
cover a top of the receptacle, the overlapped portions
are sealed with a band tape, the container has a hole,
air in the container is expelled through the hole and
displaced by gas other than air, and then the hole is
sealingly closed.
It is preferable that the container is made
of plastic.
It is preferable that the container, the band
tape and an adhesive label have a gas barrier property.
It is preferable that the receptacle and the
lid have at their edge portions flanges including
horizontal portions horizontally extending from
openings, substantial vertical portions vertically
CA 02471233 2004-06-17
- 6 -
extending from ends of the horizontal portions, and
ridges at boundaries between the horizontal and
vertical portions, and among the vertical portions of
the flanges, the vertical portion located inside with
respect to the container is longer than the vertical
portion located outside with respect to the container,
the inside vertical portion has a step at a portion in
contact with an end of the outside vertical portion,
and the band tape is adhered over the step for sealing.
It is preferable that the hole for gas
displacement is provided on a top surface of the lid.
It is preferable that the vertical portions
of the flanges vertically extend downwards from the
horizontal portions.
A packaging container according to the
present invention is characterized in that a receptacle
and a lid have at their edge portions flanges including
horizontal portions horizontally extending from
openings, and sub.>tantial vertical surfaces vertically
extending from ends of the horizontal portions, and
among the flanges, the vertical portion located inside
with respect to tre container is longer than the
vertical portion located outside with respect to the
container, and the inside vertical portion has a step
at a portion in contact with an end of the outside
vertical portion.
A ridge of the lid and/or the ridge of the
receptacle may have recesses formed in such a manner
CA 02471233 2004-06-17
7
that the vertical portion is dented inwardly and the
horizontal portion is dented downwardly.
The packaging container may have a
reinforcing surface that extends outwardly and
horizontally from, the end of the inside vertical
portion.
The present invention provides also a package
obtained by the above-described method of manufacturing
a gas displacement package.
Brief Description of the Drawings
Fig. 1 is a perspective view of a container
and a lid.
Fig. 2 _Ls a perspective view of the container
and the lid overlapped each other.
Fig. 3 is a sectional view of the container
and the lid overlapped each other.
Fig. 4 t>hows a flange of a receptacle in Fig.
l, in which Fig. 4(a) is a plan view and Fig. 4(b) is a
front view.
Fig. 5 illustrates a recess shape in a
horizontal portion and a vertical portion shown in Fig.
4, in which Fig. 5(a) shows a triangle in the
horizontal portion, Fig. 5(b) shows a semicircle or a
semi-ellipse in the horizontal portion, and Fig. 5(c)
shows a trapezoid in the horizontal portion.
Fig. 6 is a perspective view of a
configuration example with a step and a reinforcing
CA 02471233 2004-06-17
_ g
surface formed in a configuration shown in Fig. 3(a).
Fig. 7 is a plan view of a part of the flange
of the receptacle shown in Fig. 6.
Fig. 8 shows examples of shapes of a hole and
an adhesive label.
Fig. 9 is perspective views of a gas
displacement method according to the present invention.
Fig. 10 is a perspective view of a receptacle
used in the examples.
Fig. 11 is a perspective view of a lid used
in the examples.
Fig. 12 is a perspective view of the
receptacle and the lid used in the examples overlapped
each other.
Fig. 13 is a perspective view of sealing with
a band tape in the examples.
Fig. 14 is a perspective view in which the
ridges of the receptacle and the lid are overlapped and
sealed with the band tape.
Fig. 15;a) is a perspective view in which the
overlapped ridges of the receptacle and the lid are
sealed with the band tape in a clockwise direction, and
sealing has been completed with an end of the band tape
being not adhered to the receptacle and the lid, Fig.
15(b) is a perspective view in which the end of the
band tape not adhered to the receptacle and the lid is
being pulled for unsealing, and Fig. 15(c) is a
schematic diagram of ends of the band tape in Fig.
CA 02471233 2004-06-17
_ g _
15(a) overlapped each other, seen from the above.
Fig. 1Ei shows an example in which the same
receptacle and the lid as shown in Fig. 15 are used and
a cutout is formed at a side along the length of the
band tape. Fig. 16(a) is a perspective view in which
the band tape with the cutout is used, and sealing has
been completed, Fig. 16(b) is a perspective view in
which the ends of the band tape are being pulled to
cause cutting at the cutout of the band tape for
unsealing, and Fig. 16(c) is a schematic diagram of the
ends of the band tape in Fig. 16(a), seen from the
above. and
Fig. 17 shows an example in which the same
receptacle and the lid as shown in Fig. 15 are used and
a cut tape is provided in parallel with the length of
the band tape and at the center of the width of the
band tape. Fig. 1.7(a) is a perspective view in which
the band tape with the cut tape in parallel with the
length is used, and sealing has been completed, and
Fig. 17(b) is a perspective view in which an end of the
cut tape of the band tape is being pulled to separate
the band tape into two at the center by the cut tape
(upper and lower sides of the separated band tape are
still attached to the receptacle and the lid) for
unsealing the container.
Best Mode for carrying out the Invention
Now, preferred embodiments of the present
CA 02471233 2004-06-17
- 10 -
invention will be described in detail. First, a
container used in the present invention will be
described.
The container of the present invention
includes a receptacle and a lid, which may be made of
any materials. For example, the materials may include
plastic, metal, wood, paper, etc. alone, or lamination
of such materials. The lid of the present invention is
shaped to cover a top of the receptacle, and may be
made of the same materials as the receptacle. In
particular, plastic is preferable because it is clear
and allows a content to be visible, has a high gloss, a
good appearance, and a good fractional recovery system
in disposing of. A gas barrier plastic described later
is more preferable in view of preventing gas
dispersion. In order to display the container such
that it looks as if it contains a large volume of
content, it is preferable to form the receptacle to
have a smaller height than the lid covering the top. A
shape of an opening of the receptacle according to the
present invention may be a circle, a polygon such as a
triangle, a box (rectangle, square), or a rhombus, or
an indefinite shape such as an ellipse, or a curve.
The container is used in such a manner that
it is sealed with the band tape, that is, the band tape
is adhered over both edges of the receptacle and the
lid.
An overlapping portions of the receptacle and
CA 02471233 2004-06-17
- 11 -
the lid of the pz-esent invention means a portion at
which edges of the openings of the receptacle and the
lid overlap each other to close. The shapes of the
edges may be linear or curved, or may be along or not
along the shape of the receptacle as long as both edges
can overlap each other to close. The overlapping
portion is not necessarily provided at the entire edges
as long as the container can be sealed when the band
tape is adhered, but is preferably provided at an
entire periphery. Parts of the receptacle and the lid
may be joined via a hinge.
In order to efficiently and mechanically
perform sealing, and to keep stiffness of the
container, it is preferable that the overlapping
portion has flanges and they are shapes to be
overlapped at the flanges. With the flanges, attaching
the band tape to ends of the flanges, that is, ends of
vertical portions easily provides a stable seal.
The flanges refer to entire portions
extending from the edges of the openings of the
receptacle and the lid, and correspond to brim portions
at which the receptacle and the lid overlap each other
(for example, reference numeral 11 and 21 in Fig. 1).
The flanges comprise horizontal portions (reference
numeral 12 and 22 in Fig. 1), vertical portions
(reference numeral 13 and 23 in Fig. 11, and ridges at
boundaries between the horizontal and vertical portions
(reference numeral 14 and 24 in Fig. 1;.
CA 02471233 2004-06-17
- 12 -
The horizontal portions are surfaces
substantially horizontally extending from the edges of
the openings of the receptacle and the lid. The
horizontal portions may be tilted or have slight
variations in thicknesses of materials as long as they
are substantially horizontal.
The vertical portions (reference numeral 13
and 23 in Fig. 1) are surfaces substantially vertically
extending from the horizontal portions. The vertical
portions may be tilted as long as they are
substantially vertical. The direction of the extending
may be upwardly or downwardly from the horizontal
portion, or the vertical portion of the lid may be
extended upwardly and the vertical portion of the
receptacle may be extended downwardly. It is
preferable, however, both the vertical portions of the
receptacle and the lid extend downwardly because with
such structure, dust and litter hardly enter from the
overlapped portions.
As described above, providing the flange with
the vertical portion allows the band tape to be stably
attached to the vertical portion even when mechanically
attached using an attachment device etc. At this time,
it is preferable to provide a difference between
lengths of the vertical portions of the lid and the
receptacle because the band tape can be attached over
both ends of the flanges and attached even to corners
of the container without wrinkles. Especially, when an
CA 02471233 2004-06-17
- 13 -
attachment device that operates at high speeds is used
for attaching, it. is effective that the vertical
portion which is inside the container is longer than
the vertical portion which is outside the container.
Specifically, when the vertical portions are extended
downwardly from the horizontal portions, the vertical
portion of the receptacle is formed to be longer than
the vertical portion of the lid, while when the
vertical portions are extended upwardly from the
horizontal portions, the vertical portion of the lid is
formed to be longer than the vertical portion of the
receptacle. This shape of the container causes no
wrinkles of the b<~nd tape at the corners of the
container, and no reduction in sealing performance.
When sealing is carried out by using a packaging
device, even if shape or size of the container is
changed, it is possible to cope with such change only
by changing the width of the band tape or attaching
position of the band tape set in the packaging device,
thus eliminating t:he need for providing sealing parts
for each container.
Further, when the longer vertical portion is
provided with a step (reference numeral 81 in Fig. 6)
having a depth enough to accommodate a thickness of the
shorter vertical portion, the vertical portions become
flat to allow the band tape to be attached in a flat
manner, thus facilitating work, increasing strength as
a package, and facilitating handling of the package.
CA 02471233 2004-06-17
- 14 -
The vertical portion may have a length such
that the band tape can be attached over the portion,
and the length is not limited, but is preferably 2 mm
to 35 mm because the lid and the receptacle are not
easily displaced when the tape is attached, thus
facilitating attachment of the tape, increasing
stiffness of the flange, and improving the appearance.
The length is more preferably 3 mm to 30 mm, and
further preferably 4 mm to 25 mm.
If the vertical portions of the receptacle
and the lid are extended in opposite directions, it is
preferable to provide a recess or a projection for
positioning at the flange. Any locations or sizes may
be possible as long as the receptacle and the lid are
not displaced when the band tape is attached to the
boundary between t=he lid and the receptacle. The
recess or the projection is preferably provided near
the opening of the container, especially at corners
inside the receptacle in view of appearance or ease of
taking out the content. It is also preferable to
provide a recess at the horizontal portion of the
receptacle and a projection at the horizontal portion
of the lid.
Further, it is preferable to form a recess
(reference numeral 15 in Fig. 1) at the flange in order
to increase strength of the flange. This eliminates
the possibility of deformation of the flange by an
external force applied when the band tape is attached,
CA 02471233 2004-06-17
- 15 -
and prevents reduction in the appearance or sealing
performance caused by the deformation.
Further, the flange may have a fitting
thread. The fitting thread means a shape having
grooves for fitting the receptacle to the lid at the
ridges of the receptacle and the lid. The provid;_ng
manner of the fitting thread is roughly divided into
three kinds: outer fitting, inner fitting, and inner
and outer fitting. The outer fitting is a structure
not requiring high accuracy of a mold for forming the
container, and is inexpensive and easy. On the other
hand, the inner fitting requires higher accuracy of the
mold in forming the container in comparison with the
outer fitting, and is expensive, but when the content
is deli substances containing juice, it can prevent
leakage of the juice out of the container. Further,
the inner and outer fitting requires high accuracy of
the mold .in forming the container, and is very
expensive, but is the highest level fitting that
provides high fitting strength at a fitting portion and
prevents separation of the lid from the receptacle even
when some impact is applied.
The packaging container has a hole. The hole
has to be a channel through which gas flows into and
out of the packaging container which the receptacle and
the lid are sealed, and is different from a clearance
between a receptacle and a lid in a prior art gas
displacement method using a chamber. A size or a shape
CA 02471233 2004-06-17
- 16 -
of the hole, or -the number of holes may be such that
the gas can flow into and out of the packaging
container. The hole is preferably provided on the lid
in view of ease of closing the hole after the gas
displacement or preventing leakage of the content, and
more preferably on the top of the lid.
An opening area of the hole is preferably 0.3
to 3 cm~ with respect to a volume of the content of 1000
cm3 in the packaging container.
The opening shape of the hole may be such
that the gas can flow into and out of the packaging
container. For example, the opening shapes of the hole
may include a cutout shape having a complete opening
such as a square (A in Fig 8), a rectangle (B in Fig.
8), a rounded rectangle (C in Fig. 8), a polygon (D in
Fig. 8), a circle (E in Fig. 8), a semi-circle (F in
Fig. 8), an ellipse (G in Fig. 8), a semi-ellipse (H in
Fig. 8), a star (I in Fig. 8), and an indefinite shape
(J in Fig. 8), or a cutout shape having an incomplete
opening such as a quasi-horseshoe shape (O in Fig. 8),
a V shape (P in F=ig. 8), a U shape (Q in Fig. 8), a C
shape (R in Fig. 8), and an indefinite shape (S in Fig.
8). These cutout shapes are preferable because they
cause no cuttings in boring the hole in the lid.
An area of the cutout hole is represented by
the largest area when a tongue in the cutout is folded
to open the hole. The opening area of the hole differs
depending on the volumes of the contents. However, if
CA 02471233 2004-06-17
- l~ -
the opening area of the hole is 0.3 cm' smaller with
respect to the volume of the content of 1000 cm~3 in the
packaging container, resistance when air or the desired
gas flows in or out of the packaging container through
the hole becomes large because a large amount of gas
moves in and out of the packaging container in a short
time when the chamber is deaerated or the packaging
container is filled with a desired gas. Due to such
resistance, a difference in atmospheric pressure
between the inside and the outside of the packaging
container is resulted and sometimes deformation of the
packaging container occurs.
If an opening area of the hole goes over 3
cm2, the deaeration and the gas displacement can be
performed easily, but it is needed to enlarge an area
of the adhesive label for closing the hole. This
sometimes compromises the appearance of the packaging
container, and reduces mechanical strength of the
opening of the adhesive label attached over the hole.
Thus, the opening area of the hole is preferably 0.3 to
3 cm2, more preferably 0.4 to 2.8 cmy', and further
preferably 0.6 to 2.5 cmz.
The number of holes is preferably as small as
possible such that the holes are closed by one adhesive
label, in view of ease of closing the holes and
appearance of the packaging container. However, even
in a case where a large number of holes are provided,
by collectively providing a plurality of small holes at
CA 02471233 2004-06-17
- 18 -
one place, it is possible to close the small holes by
one adhesive label, so that mechanical strength of the
adhesive label is increased. Accordingly, this is
preferable.
Usually, the hole is created in a different
process from the forming, and an example of creating
the hole will be described. First, a plastic sheet is
thermally molten, and formed in conformity with a mold,
and sheet-like continuous formed products are pressed
and cut out by a cutting blade called a cutting die.
As a methods of closing the hole, various
methods such as attaching the adhesive label or filling
the hole can be considered, but closing the hole by the
adhesive label is preferable in view of the appearance
of the container and convenience. More preferably, a
print may be made on the adhesive label for product
differentiation. Materials for the adhesive label will
be described later.
Now, the present invention will be described
below with reference to the drawings.
Fig. 1 shows a perspective view of an
embodiment of a packaging container according to the
present invention. In the drawing, reference numeral
10 denotes a receptacle; 11, flange; 12, horizontal
portion; 13, vertical portion; 14, ridge; 15, recess;
20, lid; 21, flange; 22, horizontal portion; 23,
vertical portion; 24, ridge; 40, hole; and 50, adhesive
label.
CA 02471233 2004-06-17
- 19 -
The packaging container comprises the
receptacle 10 and the lid 20, and the receptacle 10 has
the flange 11 at an opening, and the lid 20 has the
flange 21 that is overlapped on the flange 11. Fig. 2
is a perspective view showing a state in which a
content is put in the receptacle 10 of the packaging
container, the lid 20 is placed on the receptacle 10,
and the vertical portions are sealed with a band tape.
In the drawing, reference numeral 30 denotes the band
tape; 40, hole; and 50, adhesive label.
The flange 11 of the receptacle 10 has the
horizontal porticn 12 hor~_zontally extending from a
periphery of the opening of the receptacle 10, and the
vertical portion 13 vertically extending from an end of
the horizontal portion 12. The flange 21 has the
horizontal portion 22 and the vertical portion 23
correspondingly to the flange 11. The receptacle has,
at part of the ridge 14, the recess 15 formed in such a
manner that the vertical portion 13 is dented inwardly
and the horizontal portion 12 is dented downwardly.
Likewise, a recess may be formed on the flange 21 of
the lid in such a manner that the vertical portion 23
is dented inwardly and the horizontal portion 22 is
dented upwardly at the ridge 24 formed by the
horizontal portion 22 and the vertical portion 23. The
recess 15 is provided in order to increase stiffness of
the flange 11, and may be provided at a portion other
than corners of the flange, but may be provided on the
CA 02471233 2004-06-17
- 20 -
corners as desired. The number of recesses 15 is not
limited.
Fig. 3 shows an example of the flanges 11,
12. Fig. 3(a) is a partial enlarged sectional view
taken along a line A-A' in Fig. l, and shows an example
in which the vertical portions 13, 23 are vertically
and downwardly e~:tended from the ends of the horizontal
portions 12, 22. In this configuration, the vertical
portion 13 of the receptacle 10 placed inside is formed
to be longer than the vertical portion 23 of the lid
20. Fig. 3(b) shows an example in which the above
described inner and outer fitting is provided in the
example of Fig. 3(a). A protrusion 17 and a groove 27
fitting over the protrusion 17 are formed in the
horizontal portions 12, 22 of the receptacle 10 and the
lid 20 in parallel to the peripheries of the openings
to strengthen the flanges 11, 21.
Fig. 9 is enlarged views of the flange 11 of
the receptacle 10 shown in Fig. 1. Fig. 4(a) is a plan
view of the flange (a top view of the horizontal
portion), and Fig. 4(b) is a front view of the flange
(a front view of the vertical portion). The dotted
line in the front view of Fig. 4(b) indicates a
position to which the vertical portior_ of the lid
overlaps.
A size of the recess 15 depends on a size or
strength of the flange 11, but when in general the
receptacle is used as a packaging container for food
CA 02471233 2004-06-17
- 21 -
products, it is preferable that the recess 15 may be a
rectangle in the horizontal portion 12 and the vertical
portion 13 as shown in Fig. 4. In this case, it is
preferable that a width (W) of the recess 15 is 1 to 20
mm, a distance (t~) between adjacent recesses 15 is 3 to
20 mm, and a depth from the vertical portion 13 is set
such that a clearance (d) remaining in a width (D) of
the horizontal potion 12 is 1 mm or more and 1/5 to
4/5 of the width (D). A depth (T) from the horizontal
portion 12 is set such that a clearance (t) between the
recess 15 and the end of the vertical portion 23 of the
flange 21 of the lid 20 indicated by t:he dotted line is
0.5 mm or more and 1/2 or less of a width (H) of the
vertical portion 13. A relationship between a width
(H) of the vertical portion 13 and the depth (T) is set
such that (H-T) leaves an enough width to attach the
band tape. When the recess 15 is provided on the
flange 21 of the lid 20, in the above-described
setting, the term "flange 11" may by replaced by the
term "flange 21".
The shape of the recess 15 may be, besides
the rectangles in the horizontal portion 12 and the
vertical portion 1_3 as shown in Figs. 1 and 4, a
triangle as shown in Fig. 5(a), a semi-circle or a
semi-ellipse as shown in Fig. 5(b), or a trapezoid as
shown in Fig. 5(c) in the horizontal portion 12. In
addition, in the case shown in Fig. 5(a), a top angle
(8) in the horizontal portion 12 is preferably 20 to
CA 02471233 2004-06-17
- 22 -
150°, and in the case shown in Fig. 5(c), a width (w) of
a top side is preferably 1 to 18 mm. In either case,
it is preferable that a depth from the vertical portion
13 is set such that a clearance (d) remaining in the
width (D) of the horizontal portion 12 is 1 mm or more
and 1/5 to 4/5 of: the width (D) . Further, a width (yV)
in the vertical portion 13, a distance (S) between the
adjacent recesses. 15, and a depth from the horizontal
portion 12 are the same as in the rectangle shown in
Fig. 4 (a) .
In the packaging container, in order to
prevent the lid 20 from slipping off the receptacle 10,
one of the flanges 11, 21 of the receptacle 10 and the
lid 20 may have a protrusion extending toward the
other, and the other of the flanges 11, 21 may have a
recess receiving the protrusion.
Fig. 6 shows an application example of the
receptacle shown in Figs. 3(a) and 3(b), in which a
step 81 extending outwardly in a horizontal direction
is formed on the vertical portion 13 at a position
below the end of the vertical portion 23, and a
reinforcing surface 82 extending outwardly in the
horizontal direction from the end of the vertical
portion 13 is formed. Fig. 7 is a partial plan view of
the flange of the receptacle shown in Fig. 6. A width
(p1) of the step ~31 is preferably within ~2 mm of a
thickness of the vertical portion 13 of the flange 11
of the lid 20. By providing the step 81, a step, which
CA 02471233 2004-06-17
- 23 -
is formed on a surface of the band tape by the end of
the vertical portion 23 when the band tape is attached,
is made to be gentler, thus improving the appearance.
The step 81 is preferably placed near the vertical
portion 23 of the lid 20, and more preferably within 2
mm from the end of the Vertical portion 23. A width
(p2) of the reinforcing surface 82 is preferably set
within 1 to 2 mm because a width less than 0.5 mm
insufficiently increases the stiffness, and a width
more than 2 mm compromises the appearance.
It is preferable that when the receptacle and
the lid of the present invention are made of
thermoplastic resin, a resin sheet previously created
is formed by a kr_own thermoforming method (such as air
pressure forming, vacuum forming, vacuum air pressure
forming).
When the receptacle and the lid are formed
from the resin sheet, any resins that are generally
used for receptacle and lids may be used. For example,
thermoplastic resins include a polyethylene resin, a
polypropylene resin, a polystyrene resin, a
methacrylate resin, a polyvinyl chloride resin, a
polycarbonate resin, a cellulose acetate resin, and the
like. When a gas barrier property is required,
thermoplastic resins include a polyamide resin, a
polyethylene terephthalate resin, a polybutylene
terephthalate resin, an ethylene-vinyl alcohol
copolymer resin (hVOH), and the like. The receptacle
CA 02471233 2004-06-17
- 24 -
and the lid are made of a single layer sheet or a
multilayer sheet made of such resins. Methods for
forming a multilayer include coextruding, various kinds
of laminating, etc. and may be appropriately selected.
The sheet used in the present invention may
be made of a material having the gas barrier property
in accordance with need.
The band tape in the present invention will
now be described. The band tape in the present
invention is a shape elongated with a width, and can
seal the packaging container by being attached over
flange surfaces extending from the receptacle and the
lid. The band tape has an adhesive on a surface to be
brought into contact with the packaging container. As
long as the receptacle and the lid can be sealed
without any clearances (tightly sealed) by the
adhesive, the band tape may have a constant width or a
varying width.
Materials for the band tape may include a
single layer or a multilayer of paper, metal thin
films, and resin, but materials including metal such as
a metal thin film or a metallized film are not
preferable in view of preventing spark caused by
electron collision in heating by a microwave oven, and
the same material as the packaging container is
preferable in view of fractional recovery. A gas
barrier resin is further preferable in order to prevent
gas dispersion from the clearance between the lid and
CA 02471233 2004-06-17
- 25 -
the receptacle.
The gas barrier band tape may be made of, for
example, two layers of a gas barrier base layer and an
adhesive layer.
The gas barrier base layer may be provided
with a gas barrier resin or a resin layer having a
laminated inorganic substance. As the resin layer
having a laminated inorganic substance, for example, a
resin layer can be considered in which an inorganic
substance of silica and/or alumina is vapor deposited
on a low density polyethylene resin layer, of which gas
barrier property is poor, to provide gas barrier
properties.
The gas barrier base layer preferably has an
amount of transmission of carbon dioxide gas of 1.0 to
4935.0 ml/mG/day MPa, an amount of transmission of
oxygen gas of 1.0 to 3948.0 ml/mz/day/MPa, and an amount
of transmission of nitrogen gas of 1.0 to 1480.5
ml/m'/day/MPa, more preferably has an amount of
transmission of carbon dioxide gas of 10.0 to 4500.0
ml/m''/day MPa, an amount of transmission of oxygen gas
of 10.0 to 2500.0 ml/mV/day/MPa, and an amount of
transmission of nitrogen gas of 10.0 to 1300.0
ml/m'/day/MPa, and further preferably has an amount of
transmission of carbon dioxide gas of 20.0 to 4000.0
ml/mz/day MPa, an amount of transmission of oxygen gas
of 20.0 to 1300.0 ml/mrlday/MPa, and an amount of
transmission of nitrogen gas of 20.0 to 1000.0
CA 02471233 2004-06-17
- 26 -
ml/m'/day/MPa. More preferably, the gas barrier base
layer has an amount of transmission of carbon dioxide
gas of 20.0 to 1000.0 ml/m'/day MPa, an amount of
transmission of oxygen gas of 20.0 to 300.0
ml/m'/day/MPa, and an amount of transmission of nitrogen
gas of 20.0 to 250.0 ml/m'-/day/MPa.
The ga:~ barrier base layer resin preferably
has an amount of transmission of oxygen gas of 1.0 to
1974.0 ml/m'/day/MPa. Gas barrier base layer resins may
include, for example, a single layer or a multilayer of
a resin compound that is composed exclusively of at
least one of the followings: a polyolefin resin (PO)
such as a polyethylene resin (HDPE, L:LDPE, etc.), a
polypropylene resin (PP), a polybutene-1 resin (PB),
and a poly-4-methylpentene-1 resin; a polyolefin
modified resin (PO modified resin) such as an ethylene-
vinyl acetate copolymer resin (EVA), an ethylene-methyl
methacrylate copolymer resin (EMA etc.), an ethylene-
vinyl alcohol copolymer resin (EVOH etc.); a polyester
resin (PEST) containing in part an aromatic component
such as a polyethylene terephthalate (including
modification) resin (PET etc.), or a polybutylene
terephthalate (including modification) resin (PBT
etc.), or containing an aliphatic component such as a
polylactic acid resin, or a polyglycol. acid resin; a
chlorine resin such as a polyvinylidene chloride resin
(PVDC), or a polyvinyl chloride resin (PVC); an alpha
olefin-carbon monoxide copolymer resin (including a
CA 02471233 2004-06-17
- 27 -
hydrogenated resin thereof); an alpha olefin (ethylene
etc.)-styrene copolymer resin (including a hydrogenated
resin thereof); <~n ethylene-cyclic hydrocarbon compound
copolymer resin (including a hydrogenated resin
thereof); a poly<~mide resin (Ny); and a caprolactone
resin, or laminat=ion of resins different from the
layers, or a drawn or undrawn tape made of these
resins. In particular, the polyester resin (PEST)
containing in part the aromatic component such as the
polyethylene resin (especially HDPE), the polypropylene
resin (PP), the ethylene-vinyl alcohol copolymer resin
(EVOH etc.), the polyamide resin (Ny), the polyethylene
terephthalate (including modification) resin (PET
etc.), or the polybutylene terephthalate (including
modification) resin (PBT etc.), or containing the
aliphatic component such as the polylactic acid resin,
or the polyglycol acid resin are preferable in view of
heat resistance and the gas barrier property. Known
additives, for example, an antioxidant, a light
stabilizer, an antistatic agent, an anti-fogging agent,
a coloring agent, or a lubricant may be mixed, or known
surface treatments, for example, a corona discharge
treatment, a flame treatment, an irradiation treatment
of electron and plasma, an ion etching treatment, or a
gas barrier coating treatment of vinylidene chloride
etc. may be performed.
The thicJkness of the gas barrier base layer
differs depending on amounts of transmission of oxygen
CA 02471233 2004-06-17
- 28 -
gas of the resin to be used, and a preferable thickness
is such that the amount of transmission of oxygen gas
is 1.0 to 1974.0 ml/m'/day/MPa. For example, in the
case of the ethylene-vinyl alcohol copolymer resin
(EVOH) that has a small amount of transmission of
oxygen gas, a required amount of transmission of oxygen
gas can be reached in some ~~m in view of the amount of
transmission of oxygen gas, but the resin has low
stiffness as the band tape, thus may be laminated with
other resins having stiffness. Such resins include,
for example, the polypropylene resin (PP). For the gas
barrier base layer made of lamination of PP and EVOH,
the amount of transmission of oxygen gas is preferably
1.0 to 1974.0 m1/m'/day/MPa, and the thickness of the
gas barrier base layer is preferably 15 to 100 ~m in
view of stiffness of the band tape. The thickness is
more preferably 20 to 90 Vim, and further preferably 25
to 85 Vim.
Adhesion in the present invention means
bonding of the band tape, and the receptacle and the
lid. Adhesion strength can be appropriately selected,
and typical adhesives are of a solvent type, a hot melt
type, a reactive type, etc. However, any adhesives can
be used, and when the content is a food product,
adhesives that comply with the Food Sanitation Law are
preferably used. The adhesives include, for example, a
rubber adhesive, an acrylic adhesive, a vinyl ether
adhesive, a silicone adhesive, or a resin compound that
CA 02471233 2004-06-17
- 29 -
is composed exclusively of at least one of them. In
view of ease of setting desired adhesive strength, the
rubber adhesive, the acrylic adhesive, and the vinyl
ether adhesive are preferable, and the rubber adhesive
and the acrylic adhesive are more preferable. In view
of reduced solvent extracts and reduced impurities, the
acrylic adhesive is further preferable.
The adhesives may contain known additives,
for example, an antioxidant, a light stabilizer, an
antistatic agent, an anti-fogging agent, or a coloring
agent, without cc>mpromising the advantage of the
present invention. In order to produce partial
separation between the gas barrier base layer and the
adhesive layer of the adhesive label. for gas
I5 displacement packaging and sealing, a silicon print
having a separation effect is previously made on the
gas barrier base layer, and so-called a tampering
prevention print may be made in which the adhesive
layer is separated from the gas barrier base layer, and
remains on the receptacle and the lid to which the
adhesive layer adheres.
The rubber adhesive may include, for example,
at least one adhesive elastomer selected from a natural
rubber exclusively composed of cis-1,4-polyisoprene; a
synthetic rubber exclusively composed of a styrene-
butadiene rubber (SBR), poly isobutylene, butyl rubber,
etc.; or a block .rubber exclusively composed of a
styrene-butadiene-styrene copolymer rubber (SBS),
CA 02471233 2004-06-17
- 30 -
styrene-isoprene-styrene copolymer rubber (SIS), etc.,
mixed with an adhesive attaching agent such as a rosin
resin, a terpene resin, a petroleum resin, or a
chroman-indene resin that is a thermoplastic resin of
an amorphous oligomer (middle molecule weight copolymer
more than a dimmer) having a molecular weight of some
hundreds to about: ten thousands in liquid or solid at
room temperature, and a softener such as mineral oil,
liquid polybutene, liquid polyisobutylene, liquid
polyacrylic ester, etc.
The acrylic adhesive may include, for
example, an adhesive reactant of a main monomer that
provides adhesion such as acrylic acid alkyl ester that
is a homopolymer generally with low Tg; a comonomer
that can be copolymerized with the main monomer and
provide cohesiveness to increase Tg, such as acrylic
acid ester of a lower alkyl group, methacrylic acid
alkyl ester, vinyl acetate, styrene, acrylonitrile; a
monomer containing a carboxyl group such as acrylic
acid or methacrylic acid (acrylate etc.); and a monomer
containing a functional group that provides adhesion
and becomes a crosslinking point such as a hydroxyl
group, an epoxy g:=pup, or an amino group, mixed with
the adhesive attaching agent, the softener, etc. in
some cases.
The vinyl ether adhesive may include, for
example, a homopolymer such as vinyl methyl ether,
vinyl ethyl ether, or vinyl isobutyl ether, or a
CA 02471233 2004-06-17
- 31 -
copolymer (an adhesive elastomer) with acrylate, mixed
with the adhesive attaching agent, the softener, etc.
in some cases.
The silicone adhesive may include, for
example, a polymer (or an adhesive elastomer) having a
residual silanol group (SiOH) at a terminal of a
polymer chain such as polydimethyl siloxane or
polydimethyl diphenyl siloxane with a high molecule
weight, mixed with the adhesive attaching agent, the
softener, etc.
The synthetic rubber adhesive or the acrylic
adhesive are preferable because the adhesive strength
can be set in a wide range in view of the gas barrier
property, especially the gas displacement packaging,
I5 and in view of food sanitation.
The adhesive strength is preferably 0.1 to 15
N/cm in a measuring method by a 180 degrees peeling
test of JIS-2-023'7 in view of adhesive strength in
adhesion and peeling strength in peeling. The adhesive
strength is more preferably 0.2 to 13 N/cm, and further
preferably 0.3 to 12 N/cm.
The thickness of the adhesive layer differs
depending on adhesives to be used, but the adhesive
strength may be 0.1 to 15N/cm and does not depend on
the thickness of the adhesive layer. For example, in
the case of the rubber adhesive or the acrylic
adhesive, the thickness of the adhesive layer is
preferably 3 to 70 Etm in view of the adhesive strength.
CA 02471233 2004-06-17
- 32 -
The thickness is more preferably 5 to 60 hum, and
further preferably 8 to 55 Vim.
The band tape preferably has a certain degree
of strength and elongation in view of mechanical
suitability when the tape is attached by a machine. In
a measurement based on an adhesive tape test of JIS-2-
0237, tensile strength is preferably 10 to 120 N/10 mm,
more preferably 20 to 110 N/10 mm, and further
preferably 25 to 95 N/10 mm. The band tape itself
preferably has flexibility in order for the band tape
to be adhered to the corners of the receptacle and the
lid without any gas dispersion area (clearance) such as
wrinkles. In an elasticity measurement of a 100 mm
long band tape (10 mm wide) under a condition of
tensile rate of 5 mm/min, the elasticity is 3 to 150
kg/mm~, more preferably 5 to 130 kg/mm~, further
preferably 7 to 110 kg/mm', in view of an adhesion state
of the band tape to the receptacle and the lid.
Further, in the case where t:he band tape is
attached to the packaging container to seal the entire
periphery, seal is realized by overlapping the band
tape once wound around the packaging container on a
front end thereof (Fig. 158c}}. When the band tape
once wound around the packaging container is overlapped
on the front end of the band tape, a slight clearance
is sometimes created along the width of the band tape
depending on the thickness of the front end of the band
tape. To fill the clearance, sealing performance may
CA 02471233 2004-06-17
- 33 -
be increased by smoothing the band tape with a spatula
to move the adhesive layer, or covering the band tape
with a hot melt agent, or various gas barrier films.
The bared tape 30 may have a function of easy
opening. For example, the band tape is provided with a
narrow portion such as a cutout (Fig. 16). Upon
opening, the band tape is broken at the narrow portion.
Alternatively, the band tape is provided with a string-
like cut tape 60 in parallel with the length of the
band tape at a center of the width of the band tape
(Fig. 17). Upon opening, the band tape sealing the
flanges of the receptacle and the lid is separated into
two at the center by the cut tape 60 (upper and lower
ends of the separated band tape are still attached to
the receptacle and the lid) to easily open the package.
With these structure, the packaging container can be
easily opened.
The adh~°sive label will be described. The
adhesive label preferably contains a c~as barrier
material. The hole is closed by the label to seal so
as to prevent a desired gas in the packaging container
from being dispersed. Thus, the adhesive label
requires tight contact with the receptacle and the lid.
The adhesive label may only require tight contact,
which may be any of sealing, bonding, ar adhesion.
The adhesive strength of the adhesive label
may be appropriately selected, and the kind or the
amount of application of the adhesive may be selected
CA 02471233 2004-06-17
- 34 -
depending on desired adhesive strength. The same
adhesives as used for the band tape may be used, but
for use of cooking by a microwave oven, an adhesive
label using an adhesive of the water or organic solvent
type or the hot melt type that has a tendency to reduce
the adhesive strength with increase in temperature in
the packaging container is preferable in view of
preventing water vapor blowout caused by increase in
internal pressure of the packaging container resulting
from heating by the microwave oven. The adhesive of
the water or organic solvent type or the hot melt type
are more preferable since they have safety in food
sanitation. The adhesive label can have any shapes as
long as it can close the hole, regardless of opening
shape of the hole. For example, the shapes may include
a square (A in Fig 8), a rectangle (B in Fig. 8), a
rounded rectangle (C in Fig. 8), a polygon (D in Fig.
8), a circle (E in Fig. 8), a semi-circle (F in Fig.
8), an ellipse (G in Fig. 8), a semi-ellipse (H in Fig.
8), a star (I in Fig. 8), and an indefinite shape (J in
Fig. 8), and a circle (K in Fig. 8), a rectangle (L in
Fig. 8), and an ellipse (I in Fig. 8) with a tab. For
the lid made of the resin sheet, uneven portions may be
created near the hole to increase stiffness of the lid
when the adhesive label is attached.
Materials of the adhesive label may include a
single layer or a multilayer of paper, metal thin
films, or resin, but materials including metal such as
CA 02471233 2004-06-17
- 35 -
a metal thin film or a metallized film are not
preferable in view of preventing spark caused by
electron collision in heating by a microwave oven, and
the same material as the packaging container is
preferable in view of fractional recovery. A gas
barrier resin is further preferable in order to prevent
gas dispersion.
The material having the gas barrier property,
the configuration, the thickness, and the performance
may be the same as described above with respect to the
band tape.
The adhesive strength of the adhesive tape is
preferably 0.1 to 10 N/cm in a measur-ing method by a
180 degrees peeling test at 25°C of JLS-Z-0237 (the 180
degrees peeling test of JIS-Z-0237: a 25 mm wide tape
is attached to a stainless plate, one end of the tape
is peeled off from the test plate toward the other end
in a 180 degrees direction at a peeling rate of 300
m/min, and a force required for the peeling is measured
and used), in view of the adhesive strength upon
adhesion and the peeling strength upon peeling. The
adhesive strength is preferably 0.2 to 9.5 N/cm, and
more preferably 0.3 to 7.5 N/cm. A measured value by
the 180 degrees peeling test at 80°C is preferably lower
than a measured value by the 180 degrees peeling test
at 25°C in view of the adhesive label automatically
peeling off by the increase in the internal pressure of
the packaging container. The measured value by the 180
CA 02471233 2004-06-17
- 36 -
degrees peeling test at 25°C is preferably 0.1 to 8 N/cm
in view of the adhesive strength upon adhesion and the
peeling strength upon peeling. The measured value is
more preferably 0.2 to 7.5 N/cm, and further preferably
0.3 to 5.5 N/cm.
The thickness of the adhesive layer differs
depending on the adhesives to be used, but the adhesive
strength may be 0.1 to 10N/cm in the measuring method
by the 180 degrees peeling test at 25°C, and does not
depend on the thickness of the adhesive layer. For
example, in the case of the rubber adhesive or the
acrylic adhesive, the thickness of the adhesive layer
is preferably 2 to 10 ~m in view of the adhesive
strength. The thickness is more preferably 3 to 90 Vim,
and further preferably 5 to 85 ~tm.
The gas barrier adhesive label has a certain
degree of strength in view of preventing breakage
caused by externa~ puncture. In a measurement based on
Article 10 of the Japan Agriculture Standard, puncture
strength is preferably 2.0 N and more, more preferably
2.5 N and more, arid further preferably 3.0 N and more.
Further, the adhesive label may have a tab for ease of
opening. For example, it is preferable in view of
prevention of blowout in heating the packaging
container that the adhesive label has a semi-circular
tab which is pulled up from the lid to easily open the
packaging container for ease of opening.
Main contents of the packaging container are
CA 02471233 2004-06-17
- 37 -
cooked food products, for example, delis (boiled,
baked, steamed, or fried foods) or boxed meals sold at
supermarkets or convenience stores.
Now, a packaging method according to the
present invention will be described.
The packaging method according to the present
invention is a ga.s displacement sealing method in which
the hole 40 is used to perform deaeraticn and gas
displacement in a chamber, and the hole is closed after
the gas displacement. Thus, gas in a space or the
content in the packaging container is displaced by a
desired gas. Specifically, after deaerating the
chamber, gas displacement is performed by an inert gas,
thereby causing deaeration and gas displacement in the
packaging container via the hole provided on the
container. The deaeration and the gas displacement in
the chamber substantially eliminate a difference in
atmospheric pressures between the inside of the
packaging container and the inside of the chamber (the
outside of the packaging container) to prevent the
packaging containE>_r from being crushed by the
difference in the atmospheric pressures.
The gas displacement means that air in the
packaging container is displaced by a desired gas,
which contributes to increase in shelf life of the
contents and to prevent color variation of the product.
For example, holding food products in an inert gas
atmosphere contributes to (1) preventing oxidation of
CA 02471233 2004-06-17
- 38 -
oil and fat content, (2) preserving active ingredients
such as Vitamins, (3) preventing rot caused by
development of mold, bacteria, or yeast, (4) preventing
discoloration and fading, and (5) preventing loss of
flavor, etc. Further, displacement by a gas such as
carbon dioxide having bacteriostasis can sometimes
increase the shelf life of the contents.
Any gases generally known can be used in the
present invention. For example, nitrogen, carbon
dioxide, oxygen, argon, etc. can be used alone or in
combination thereof. Ozone or natural and synthetic
antibacterial substances (for example, hinokitiol)
generally known as bactericide for mo_Ld, bacteria, or
yeast may be used.
As a method of deaeration and gas
displacement in the chamber, a general chamber type gas
displacement method can be used. Generally known gas
displacement methods are of the chamber type and the
gas flushing type. Fig. 9 shows a chamber type gas
displacement method according to the present invention.
The chamber type gas displacement method according to
the present invention is a method in which the
packaging container, of which the receptacle 10 and the
lid 20 (hole 40) are sealed with the band tape 30, is
placed in the space in the chamber (reference numeral
70 in Fig. 9), the whole of the air in the chamber is
expelled to be vacuum once (B in Fig. 9), and then a
desired gas is fed into the chamber under Vacuum for
CA 02471233 2004-06-17
- 39 -
gas displacement. The adhesive label 50 is attached to
the hole 40 of the lid 20 in the chamber to seal the
space in the packaging container (C in Fig. 9).
Generally, the chamber type gas displacement
method can provide a high rate of gas displacement and
reliable gas displacement, while the gas flushing type
gas displacement method tends to provide a low rate of
gas displacement though it is simple and inexpensive.
The gas displacement method according to the present
invention is cf the chamber type described above, and
the air in the space and the contents in the packaging
container is reliably displaced by gas to increase the
shelf life of the content and to prevent discoloration
of the product, thereby allowing displacement in the
packaging container at the high rate.
An example of a sealing method of sealing a
packaging container comprising the receptacle and the
lid with a band tape according to the present invention
will be described with reference to the drawings. A
rectangular receptacle (Fig. 10) and a lid (Fig. 11)
are used and ridges of the receptacle and the lid (Fig.
12) overlap each other, and the ridges are sealed with
the band tape (Fig. 13). Fig. 13 is a perspective view
showing a state in which the overlapping ridges of the
receptacle and the lid are being sealed in a clockwise
direction with the band tape. Fig. 14 is a perspective
view showing a state in which the overlapping ridges of
the receptacle and the lid have been sealed with the
CA 02471233 2004-06-17
- 40 -
band tape. The bonding direction of the band tape may
be in the clockwise direction as shown or in the
counterclockwise direction, as long as the overlapping
ridges of the receptacle and the lid can be sealed with
the band tape. As described above, the receptacle and
the lid are sealed with the band tape, therefore
receptacles and lids of any shapes can be sealed with
the band tape. Thus, this sealing method is excellent.
An example of ease of opening will be
described with reference to Figs 15, 16, and 17. Figs
15, 16, and 17 show a process of causing only the
ridges of the rectangular receptacle and lid to overlap
each other, and sealing the receptacle and the lid with
the band tape having adhesion. The band tape in Figs
15, 16, and 17 is attached so as to achieve the ease of
opening, or the band tape itself is formed to achieve
the ease of opening.
Example: shown in Figs 15, 16, and 17 will be
described in detail. Fig. 15(a) is a perspective view
showing a state in which the overlapping ridges of the
rectangular receptacle and lid are sealed in the
clockwise direction with the band tape, and sealing has
been completed with a rear end of the band tape being
not adhered to the receptacle and the lid. Fig. 15(b)
is a perspective view showing a state in which the rear
end of the band tape not adhered to the receptacle and
the lid is being pulled for opening. Fig. 15(c) is a
schematic diagram of ends of the band tape in Fig.
CA 02471233 2004-06-17
- 41 -
15(a) overlapping each other, seen from the above. As
methods for giving no adhesive only to the rear end of
the tape as described above, there are a method in
which a circumferential dimension of the packaging
container is previously measured, and only an
overlapping portion of the tape is not coated with an
adhesive, and a method in which a band tape across
which an adhesive is applied is used, and adhesive
surfaces at the rear end of the tape only are attached
to each other. The latter method is simple and
preferable. Fig. 16 shows an example in which the same
receptacle and the lid as the example shown in Fig. 15
are used and a cutout at a side along the length of the
band tape is provided. Like the example shown in Fig.
15, Fig. 16(a) is a perspective view showing a state in
which the band tape with the cutout is used, and
sealing has been completed. Fig. 16(b) is a
perspective view showing a state in which the rear end
of the band tape is being pulled to cause breakage at
the cutout of the band tape for opening. Fig. 16(c) is
a schematic diagram of the ends of the band tape in
Fig. 16(a), seen from the above. As described above,
pulling the rear end causes the band tape to be cut
from the cutout near the rear end of the band tape,
thereby facilitating opening. The cutout of the band
tape may be created at part of the side of the band
tape as shown in fig. 16, or may be created across the
side or at both sides as long as the tape is cut when
CA 02471233 2004-06-17
- 42 -
pulled. Fig. 17 shows an example in which the same
receptacle and the lid as shown in Fig. 15 are used and
a cut tape is provided in parallel with the length of
the band tape at the center along the width of the band
tape. Like Fig. 15, Fig. 17(a) is a perspective view
showing a state in which the band tape with the cut
tape 60 in parallel with the length is used, and
sealing has been completed. Fig. 17(b) is a
perspective view showing a state in which a rear end of
the cut tape of the band tape with the cut tape in
parallel with the length is being pulled to separate
the band tape into two at the center by the cut tape
(upper and lower ends of the separated band tape are
still attached to the receptacle and the lid) for
opening the packaging container. The method in which
the cut tape is provide in parallel with the length of
the band tape at t:he center of the width of the band
tape, and the band tape sealing the ridges of the
receptacle and the lid is separated into two at the
center by the cut tape to easily open the packaging
container is preferable in view of ease of opening. A
color of the cut tape may be differed from a color of
the band tape for clarity.
Now, measuring methods and examples will be
described in detail.
(1) Measuring an amount of transmission of
oxygen gas
An amount of transmission of oxygen gas was
CA 02471233 2004-06-17
- 43 -
measured in accordance with ASTM-D-3985 (at a
measurement temperature of 23°C).
(2) Measuring a percentage of oxygen
composition in a space in a packaging container
A percentage of oxygen composition in a space
in a packaging container at 23°C and 50% RH was measured
using Checkpoint manufactured by PBI-Dansensor A/S.
G(good): The percentage of oxygen composition
in the space in the packaging container after ten days
is less than lo.
M(moderate): The percentage of oxygen
composition in th~? space in the packaging container
after ten days is to or more and less than 20.
P(poor): The percentage of oxygen composition
in the space in the packaging container after ten days
is 20 or more.
(3) Cooking hamburgers
Minced beef and pork (5:5) of 1 kg and 2
middle size eggs were kneaded to become viscous while
being cooled to 5°C or less, and then 0.3 kg fried onion
and 0.12 kg bread crumbs were added and further
kneaded. The kneaded materials were divided into 120 g
portions, shaped into an oval shape, placed in a 120°C
oven and heated until a central temperature reaches 70°C
to cook hamburgers.
(4) Measuring a preservation temperature
A temperature was measured for every 10
minutes using Button Type Cool Memory manufactured by
CA 02471233 2004-06-17
- 44 -
Sanyo Electric Co., Ltd. A cooked food product was
packaged, and then preserved in Open Showcase EA-MS
manufactured by Mitsubishi Electric Corporation (at a
preservation temperature of 15°C).
(5) Measuring general viable cell count
A hamburger of 1 g was successively diluted
with up to ten parts of water, and diluted sample
solutions were prepared. Two deep petri dishes were
provided for each dilution stage, and each diluted
sample solution was poured into each dish by 1 ml. A
standard agar medium of 15 ml that is previously
subjected to high pressure steam sterilization and then
held at about 45°C: was aseptically poured into each
dish, calmly mixed such that the diluted sample
solution and the medium immediately mixed well, and
calmly left until the medium completely solidified.
The operation from pouring the diluted sample solution
into the dish to mixing with the medium was finished
within 20 minutes, and when the medium solidified, the
dish was inverted, a surface of the medium was dried
for 30 minutes in an incubator to perform cultivation
at 35°C for 48 hours. Then, the number of development
colonies on a plate in which 30 to 300 cells developed
was measured, the numbers of colonies on two plates
were averaged and multiplied by multiples of dilution
to determine viable cell count for the food product of
1 g.
Examples 1 to 6
CA 02471233 2004-06-17
- 45 -
An undrawn barrier multilayer film was
attached to a polypropylene resin sheet with filler for
a receptacle, and a polystyrene resin sheet for a lid,
using a polyurethane dry laminate adhesive to form a
multilayer resin sheet. The multilayer resin sheet was
thermoformed into shapes shown in Figs. 10 (the
receptacle), 11 (the lid), and 12 (the lid placed on
the receptacle). The lid was formed with a C-shaped
hole having a 25 cm diameter on a top thereof by a
punch after forming and before drawing a formed
product. Substantially vertical flanges of the
receptacle and the lid were sealed with a band tape
shown in the examples. The volume in a packaging
container was 800 cm3. The packaging container is
subjected to vacuum and gas displacement using a
chamber, air in the packaging container was displaced
by a high purity nitrogen gas (purity 99.990), the C-
shaped hole on the lid was sealed with a circular
adhesive label having a 35 cm diameter shown in the
examples, and then., gas composition in the packaging
container was measured immediately after sealing, one
day after the sealing, and 10 days after the sealing.
The conditions and results will be shown in Table 1.
Further, a hamburger as an example of a food product
was placed in the packaging container with the volume
of 800 cmJ used in the examples of the packaging
container, and a mixed gas of carbon dioxide and
nitrogen (1:1) was used to perform vacuum type gas
CA 02471233 2004-06-17
- 46 -
displacement packaging. Some samples prepared as
described above were provided and preserved for a week
at various temperatures to determine general viable
cell count at certain times. The general viable cell
count was determined for random samples selected from
some samples provided under the same conditions. The
conditions and the results will be shown in Table 1.
Comparative example 1
The same experiment as the examples was
conducted except for using a polypropylene resin sheet
with filler for the receptacle, and a polystyrene resin
sheet for the lid. The conditions and the results will
be shown in Table 1.
According to the present invention, the gas
displacement is performed after the deaeration in the
chamber, thus the air in the space and the content in
the packaging container can be displaced by gas at a
high rate of displacement in comparison with the gas
flush type gas di~;placement method. Seal packaging
requires no heat-shrinkable film, thus reducing the
number of packaging materials to be used, and
entrepreneur's bearing of cost based on the Container
and Package Recycling Law. Further, the overlapping
ridges of the receptacle and the lid can be sealed with
the band tape to enclose the packaging container, so
that even if the shape or the size of the packaging
containers changes when performing packaging by using a
device, a height of the band tape may be only adjusted
CA 02471233 2004-06-17
- 47 -
to match a height of the overlapping ridges of the
receptacle and the lid. There is no :need for selecting
materials for the plastic package, and opening is
extremely easy.
CA 02471233 2004-06-17
- 48 -
Table 1
ExampleExampleExampleExample ExampleExampleComparative
I 2 3 4 5 6
example
1
MuISilayer
film
Layer OutermostPP N1' NY NY NY PP
layer
configu-
CoextrusionCoextrusionCoextrusionCoextrusionCoextrusionCoextrusion
ration Thickness7 5 5 5 5 7
(Itm)
InternalAdhesiveEVOH EVOFI EVOH EVOH Adhesive
layer layer layer
CoextrusionCoextrusionC'oextrusionCoextrusionCoextrusionCoextrusion
Thickness5 5 S S S 5
(pm)
InternalEVOH NY NY NY NY EVOH
layer
(.'oextrusionCoextrusionCoextrusionCoextrusionCoextrusionCoextrusion
Thickness6 5 5 5 5 G
(gym)
InternalAdhesiveAdhesiveAdhesiveAdhesiveAdhesiveAdhesive
layer layer layer layer layer layer layer
CuextrusionCoextrusionCoextrusionCoextrusionCoextrusionCoextrusion
Thickness5 5 5 5 5 5
(pm)
InternalPP PP PS LL EVA PP
layer
(laminateCoextrusionCoextrusion( oextrusionCoextrusionCoextrusionCoextrusion
surface)
Thickness(pm)7 30 30 30 30 7
Thickness 30 50 5(1 50 Sll 3U
of
multilayer
film
(pm)
Adhesive UrethaneUrethaneUrethaneUrethaneUrethaneUrethane
layer
(dry
laminate)
Thickness 5 5 5 5 5 5
(pm)
Resin PP fillerPP fillerPP tillerPP fillerPP fillerYP fillerPP
filler
sheet
for
container
Draw Undr;twnllndrawnUndrawnUndrawn UndrawnUndrawnUndrawn
ratio
Length
to
width
Thickness(Itm) 450 450 450 450 450 450 450
02TR Less Less Less Less Less Less SOUU
mllmilD/MPa than than than than then than or
10 10 lU IO 10 10 more
Mulfilayer
film
LayerOutermostPP NY N1' NY NY Nl'
layer
cuntigu-
CoextrusionCoextrusionC'oextrusionCoextrusionCoextrusionCoextrusion
rationThickness7 5 S 5 5 5
(pm)
Internal:ldhesivelayerEVOFI EVOII EVOlI EVOlI EVOH
layer
CoextrusiunCoextrusionCoextrusionCoextrusionCoextrusionCoextrusion
Thickness5 5 5 5 5 5
(pm)
InternalEVOH NY NY NY NY NY
layer
CoextrusionCoextrusionCoextrusionCoextrusionCoextrusionCoextrusion
Thickness6 5 5 5 5 5
(pm)
InternalAdhesiveAdhesiveAdhesiveAdhesiveAdhesiveAdhesive
layer layer layer Payer layer layer layer
ThicknessCoextrusionCoextrusionCoextrusionCoextrusionCuextrusionCoextrusion
(pm)
5 5 5 5 5 5
InfernalPP PP PS LL EVA EVA
layer
(laminateCoextrusionCoextrusionCoextrusionCoextrusionCoextrusionCoextrusiun
surface)
Thickness7 30 30 30 30 30
(Itm)
Thickness 30 Sll 50 50 50 SU
of
multilayer
tihn
(Itm)
Adhesive UrethaneUrethaneUrethaneUrethaneUrethaneUrethane
layer
(dry
laminate)
Thickness ~ 5 5 5 5 5
(um)
Resin OPS OPS OPS OPS OPS OPS OPS
sheet
for
lid
Drawratio 4x4 4x4 4x4 4x4 4x4 4x4 4x4
Length
towidth
Thickness(pm) 250 250 250 250 250 25U 250
02TR Less Less Less Less Less Less 5000
ml/m'/D/MPa than than than than than than or
10 10 10 10 10 111 more
Band Fitm NY NY PP/EVOH/fPYY/EVOH1PPPP/EVOH1PPPPIEVOH1PPNl'
tape
Thickness30 30 30 30 30 30 30
(ltm)
Adhesive Synthetic Synthetic Synthetic
Acrylic Acrylic Acrylic Acrylic
Amount 25 rubber 25 rubber ~5 rubber 25
of coating
(g/m') 35 25 25
Adhesive Film PET PET PET PET PE'f PE'f PET
label
Thickness(wm)75 50 75 5U 75 75 75
AdhesiveAcrylicAcrylicAcrylicAcrylic AcrylicAcrylicAcrylic
Amount 25 25 25 25 25 25 25
of coating
(g/m
)
Concentration ImmediatelyG G G G G G (:
of after
oxygen sealing
in
package
One day G G G G G G M
later
Ten daysG G G G G G P
later
General Immediately1.1 1.1 1.1 1.1 x 1.1 1.1 1.1
viable after x 10' x 10' x 10' 10' x 10' x 10' x 10'
cell
count One day 4.4 4.3 7.4 2.4 x 3.4 2.4 6.4
later x l0_' x lU' x lU' l0' x IU' x 10' x 10'
Three 3.2 2.2 3.8 3.2 x 3.~ 3.6 2.2
days x 10~ x 10' x 10' 10~ x 10' x 10~ x 10'
later ~ I +
Seven 6.3 6.7 S.9 4.5 x S.3 S.2 8.3
davs x 10' x 10' x 10' 10' x 10' x IU' x 10"
later
PP: Propylene resin NY: Nylon resin EVOH: Ethylene-vinyl acetate copolymer
saponified resin
LL: Linear polyethylene resin EVA: Ethylene-vinyl acetate copolymer resin
Adhesive layer: Malefic acid modified polyolefin resin PS: Polystyrene resin
