Note: Descriptions are shown in the official language in which they were submitted.
08939131CA
SELF-VENTING ADHESIVE PATCH FOR MICROWAVABLE
FOOD PACKAGING BAGS
TECHNICAL FIELD
[0001] The
present disclosure relates to food packaging bags and in particular
to steam venting microwavable flexible packaging bags.
BACKGROUND
[0002]
Flexible packaging bags built with laminated film structures can be used
in microwave ovens to cook or reheat various types of foods. For some food
products
that are raw or pre-cooked the technology required for venting the packaging
bags is
more complex than simple open holes in the bag wall. Some food products
require a
closed system that has a hermetic seal until the time the product is cooked or
reheated
in the microwave. Some global markets require hermetically sealed packaging
regardless of the products.
[0003] Common
microwave steam venting methods use small slits or
perforations in the packages but they are open to the elements at all times
and not
considered hermetically sealed. One of the solutions is to pack food in an
airtight
hermetically sealed package and have the end user puncture the bag with a
sharp
utensil creating a crude steam vent and then heating in the microwave. However
the
variability of steam vent rate can impact the consistency in the cooking of
the food
product. Alternatively the bag may be pre-perforated during manufacturing and
then
cover the opening with a releasable pressure sensitive adhesive patch. The end
user
is then tasked with manipulating or removing the patch before microwaving in
order
to open the steam vent holes.
[0004] Existing
solutions require the end user to ensure venting occurs which
adds variability to the outcome of the microwave cooking process and once the
patch
is removed the package is prone to leaking liquids and sauces when handling
after
cooking. If the vent has not been opened manually the bags may explode under
pressure in the microwave. Other self-venting technologies rely on high
temperatures
to dissolve or melt bonds, seals and fillers, where fillers refer to a porous
material filled
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with something that melts and that is what opens the vent. These solutions do
not
allow the package to be resealed and require a specific temperature to be
achieved
in order to dissolve or melt the bond.
[0005] Accordingly, systems and methods that enable improved venting
of
microwavable food packaging bags remains highly desirable.
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SUMMARY
[0006] One general aspect includes a self-venting adhesive patch made
from
a film material. The self - venting adhesive patch also includes a permanent
stronger
bond adhesive zone applied to a surface of the film material; a releasable
lesser bond
adhesive zone adjacent to the permanent adhesive zone on the surface of the
film
material; and a non-adhesive zone within the permanent adhesive zone on the
surface of the film for covering a vent formed in a microwavable packaging
material
covered by the self-venting adhesive patch, the non-adhesive zone directing
steam
pressure towards the releasable adhesive zone; where a package, formed from
the
microwavable packaging material, vents steam pressure to the self-venting
adhesive
generated during cooking of contents of the package, the steam pressure
expands
the non-adhesive zone and vents into the releasable adhesive zone, allowing
steam
to be vented from the vent, through the releasable lesser bond adhesive zone.
[0007] Implementations may include one or more of the following features.
The
self-venting adhesive patch where the permanent adhesive is a stronger bond
adhesive and the releasable adhesive zone is a lesser bond adhesive. The self-
venting adhesive patch may include a separation zone between the permanent
adhesive zone and the releasable adhesive zone. At least a portion of the
separation
zone may be formed by the permanent stronger bond adhesive zone. The non-
adhesive zone is formed by application of a second film material over a
portion of the
permanent adhesive zone. The adhesives are food grade adhesives or adhesives
suitable for indirect food contact. The vent within the packaging material the
perforations are selected from a group may include: slits, round holes,
semicircular
cuts, cross shaped cuts, v-shaped cuts, needle punches, and laser
perforations. The
adhesive patch is applied to packaging material roll-stock prior to forming a
package
from the flexible packaging material. The adhesive patch is applied to a
formed
package aligned with a perforation in a wall of the formed package. The
releasable
adhesive can partially re-seal to the microwavable packaging material when
cooled
after being heated. The shape of the non-adhesive zone provides proportionally
larger
perimeter length with the permanent adhesive zone than a perimeter length of
the
releasable adhesive zone. The vent is formed by a semi-circular cut. The patch
is
circular. The shape of the non-adhesive zone is triangular shaped. The shape
of the
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08939131CA
non-adhesive zone is bulb shaped. A separation zone is between the permanent
adhesive zone and the releasable adhesive zone. The releasable lesser bond
adhesive zone is formed by a plurality of sub-zones. A method of manufacturing
a
flexible package with an adhesive patch, the method may include: receiving a
rollstock
material; perforating the rollstock material to form a vent opening; applying
a self-
venting adhesive patch to a side of the rollstock over the perforation in the
rollstock
material.
[0008] One general aspect includes a method of manufacturing an
adhesive
patch for application to a microwaveable package. The method of manufacturing
also
includes applying a permanent adhesive to a film material in a permanent
adhesive
zone; applying a releasable adhesive to the film material adjacent to the
permanent
adhesive in a releasable adhesive zone, where a non-adhesive zone is formed
within
the permanent adhesive zone which allows the releasable adhesive zone to
release
from microwavable package when steam pressure is released from moisture in
food
contents within the microwavable package.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Further features and advantages of the present disclosure will
become
apparent from the following detailed description, taken in combination with
the
appended drawings, in which:
FIG. 1 shows a representation of microwavable packaging bag having a self-
venting
adhesive patch;
FIG. 2 shows a top view of the self-venting adhesive patch;
FIG. 3 shows a side view of the self-venting adhesive patch while venting;
FIG. 4 shows a representation of a pillow packaging bag having a self-venting
adhesive patch;
FIG. 5 shows a representation of a bottom gusset stand-up pouch bag having a
self-
venting adhesive patch;
FIG. 6 shows a representation of roll-stock having self-venting adhesive
patches
applied thereon;
FIG. 7 shows a method of manufacturing a flexible packaging bag having a self-
venting adhesive patch; and
FIG. 8 shows a top view of an alternative venting adhesive patch.
[0010] It will be noted that throughout the appended drawings, like
features are
identified by like reference numerals.
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DETAILED DESCRIPTION
[0011] Embodiments are described below, by way of example only, with
reference to Figs. 1-8.
[0012] Implementations may include one or more of the following
features. The
method where the adhesive patch is applied to roll-stock material for forming
the
flexible packaging material.
[0013] A self-venting adhesive patch is disclosed for "microwave in
bag"
applications. The self-venting adhesive patch covers a steam vent opening in
microwavable food packaging bag and lifts away from the opening during
cooking.
The patch provides a self-venting solution for a hermetically sealed bag
without
requiring end user involvement in removing the patch or opening the vent prior
to
cooking. A portion of the patch remains anchored to the package at all times.
The
patch can be pre-applied to film, applied to a premade package during bag
making or
integrated inline at the packer and applied to the film web during packing.
The patches
can be applied in any location on the film web covering a vent opening in the
film.
[0014] FIG. 1 shows a representation of microwavable packaging bag
having
a self-venting adhesive patch 100. The patch 100 can be made from film
material
with at least two different adhesive zones which adhere to a side 104 of a
packaging
bag 102. The package made from a laminated structure is sealed along the edges
of
the package 106. The food product can be placed within the bag through an
opening
108 which is then sealed. The patch 100 can be clear, colored, opaque or
printed
with color ink or text.
[0015] FIG. 2 shows a top view of the self-venting adhesive patch
100. The
self-venting patch 100 comprises a permanent (stronger bond) adhesive zone 210
meant to keep the patch in place and anchored to the bag. The characteristics
of this
adhesive allows it to stay adhered to the package under high pressure and
temperatures during heating. A releasable (lesser bond) adhesive zone 220 that
is
intended to release from the package when under pressure due to heating. The
characteristics of this adhesive allows it to lift away only when exposed to
steam
pressure in a microwave. The adhesives will partially re-adhere to package
after
cooking, providing a semi-sealed package and prevent leaks of liquids or
sauces.
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Adhesives are designed to withstand exposure to cold, heat, oils, fats, and
liquids for
frozen food products and typical range of environments from packing, freezing
and
heating. The adhesives are food grade or suitable for indirect food contact.
The two
different adhesive zones can be defined by the size of the zones using the
same
adhesive, different types of adhesives in each zone, or the size and types of
adhesives in each zone. The permanent (stronger bond) adhesive zone 210 may be
same adhesive as the releasable (lesser bond) adhesive zone 220 however more
adhesive may be utilized in a pattern providing lesser bond strength.
[0016] A non-adhesive zone 212 of the patch 100 covers a small
opening 204
formed in a bag by a slit/perforations on rollstock film. The non-adhesive
zone 212
can vary in shape and function for directing the flow of steam pressure and
varying
the vent release times. In the embodiment shown the non-adhesive zone 212 is
provided in a generally triangular shape, having two sides adjacent the non-
adhesive
zone 212 and one side adjacent to the lesser bond zone 220. The holes or slits
204
can be formed in a variety of ways depending on the steam venting or cooking
requirements. Openings in the bags can be formed in many shapes and
configurations and include but not limited to slits, round holes, semicircular
cuts, cross
shaped cuts, v-shaped cuts, needle punches, laser perforations etc. Depending
on
the food product application and customer requirements a separation zone 230
between the releasable adhesive area (lesser bond) zone 220 and permanent
adhesive zone (stronger bond) zone 210 can provide a stronger hermetic seal
and/or
allow pressure to build further before vent release. Varying the width of this
threshold
area is a simple way to control pressure levels inside the package by changing
the
time for vent release. Some situations may require a longer time period under
pressure for desired cooking results.
[0017] The separation zone 230 separates during product heating and
lift due
to steam pressure. The separation zone 230 may utilize the same adhesive as
permanent (stronger bond) adhesive zone with a lesser quantity as the
permanent
adhesive zone 210 in a narrow band that the steam has to break through to get
to the
releasable adhesive. The band can be ruptured due to the pressure of the
venting
to provide a hermetic seal prior to heating. Alternatively the separation zone
may be
sufficiently narrow to enable steam pressure to cause separation or rupture of
the
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stronger bond adhesive in the narrow zone. The separation zone 230 may
alternatively be defined by the absence of an adhesive, partial use of the
adhesive,
intermittent use of the adhesive, or use of a different type of adhesive or by
the
placement of another layer of patch material. As pressure increases the
separation
zone 230 will lift from the packaging material opening a portion 222. The
separation
zone 230 and the releasable adhesive area zone may comprise multiple or
plurality
of zone locations along or around the non-adhesive zone 212.
[0018] Specific design elements such as shape/measurements of the no-
adhesive area 212, and the shape/measurements of the patch can be tailored for
specific cooking needs, and is not limited to the example presented here. The
patch
may be formed in a number of shapes, for example circular, rectangular,
triangular
etc. The dimensions of the patch and the adhesive zones and non-adhesive zones
may be variable depending on venting requirements. The patch may for example
be
1" in diameter although the dimensions may vary. However different shapes and
.. zones can be utilized as would be understood by a person of skill in the
art, the shape
and orientation will depend on the type of bag, product being cooked, filling,
venting
and handling requirements. For example, the vent may be positioned towards the
top
of the package to reduce leakage of liquids when handled after cooking. The
non-
adhesive zone 212 can be absent of adhesive or substantially lack adhesive
compared to the other adhesive zones of the patch.
[0019] FIG. 3 show a side view of the self-venting adhesive patch
while venting
is occurring. As the food within the packaging bag is heated by a microwave,
steam
pressure 300 vents through openings in the packaging material 104 applying
pressure
to the non-adhesive zone 212. As the non-adhesive zone 212 lifts, the
separation
zone 230 will also open and allow steam to move towards the releasable lesser
bond
adhesive zone 220 causing it to lift from the surface of the packaging
material 104
enabling release of the steam 300. As the contents of the package cools and
the
steam pressure lowers, the separation zone 230 and/or the releasable adhesive
zone
220 can partially reseal to the packaging material surface 104.
[0020] FIG. 4 shows a representation of a pillow packaging bag 400 having
the
self-venting adhesive patch 100. The patch 100 may be placed on portion 402,
such
as a fin seal 404 up the middle of the bag 400. The patch 100 can be
positioned on
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a front panel or one or more of the two back panels (either side of the fin
seal). The
vent typically goes on one of the two back panels and the bag goes in the
microwave
face down such that the vent is positioned upright during cooking.
[0021] FIG. 5 shows a representation of a bottom gusset stand up
pouch bag
having the self-venting adhesive patch 100. The three-side bag having sealed
sides
portions 504 and bottom portion 506 to enable the bag 500 to stand up for
filling
through opening 510. The opening 510 of the bag is sealed once contents are
placed
in the bag 500. The vent 100 can be positioned at the top portion of the bag
500 to
allow the steam to vent upwards.
[0022] As shown in Figure 6, the patches such as self-venting patch 100 can
be pre-applied on a rollstock product 600 (provided in roll form) with
perforations made
on the exterior of the rollstock product 600. The customer forms, fills and
seals the
package created from the rollstock product 600 in their packing facility or
patches
100a, 100b can be applied inline on film web running on pre-made bag making
machines or packer's form fill seal machines.
[0023] FIG. 7 shows a method 700 of manufacturing a flexible
packaging bag
having an adhesive patch. A rollstock material is received for forming the
flexible
packaging bag (702). The rollstock is made of laminated film structures for
"microwave in bag" applications. The rollstock is cut or perforated to provide
an
opening (704) through the surface of the material. Each patch is aligned with
the
rollstock (706) and a patch is applied (708) to the material. The patch is
applied by
pressure sensitive adhesive. The rollstock is then utilized to form a package
(710)
with the patch being placed on the exterior of the package. The bag can then
be filled
(712) and then sealed (714). Alternatively, the self-venting adhesive patch
100 can
be applied over a perforating/cut in the packaging bag after it is
manufactured.
[0024] FIG. 8 shows a top view of an alternative embodiment of self-
venting
adhesive patch 800. The self-venting patch 800 comprises a permanent (stronger
bond) adhesive zone 810 that keeps the patch 800 in place and anchored to the
bag.
A releasable (lesser bond) adhesive zone 820 is intended to release from the
package
when under pressure due to heating. A non-adhesive zone 812 is provided in a
bulb
shape or elliptical shape that covers the opening 204 formed in the bag by a
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slit/perforations on roll-stock film. A smaller portion of the non-adhesive
zone 812 is
directed towards the releasable (lesser bond) adhesive zone 820. A separation
zone
830 can be provided between the permanent adhesive zone 810 and the lesser
adhesive zone 820. The separation zone 830, and entry to the lesser adhesive
zone
820, presents a proportionally lesser or shorter perimeter length than the
perimeter of
the permanent adhesive zone 810.
[0025] It would be appreciated by one of ordinary skill in the art
that the system
and components shown in Figures 1-8 may include components not shown in the
drawings. For simplicity and clarity of the illustration, elements in the
figures are not
necessarily to scale, are only schematic and are non-limiting of the elements
structures. It will be apparent to persons skilled in the art that a number of
variations
and modifications can be made without departing from the scope of the
invention as
defined in the claims.
Date Recue/Date Received 2022-02-04
