U.S. patent application number 11/989430 was filed with the patent office on 2010-11-04 for reclosable microwave-suitable packaging.
Invention is credited to Friedrich Kastner, Gyula Madai, Stefan Zoister.
Application Number | 20100276327 11/989430 |
Document ID | / |
Family ID | 37562084 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100276327 |
Kind Code |
A1 |
Kastner; Friedrich ; et
al. |
November 4, 2010 |
Reclosable Microwave-Suitable Packaging
Abstract
The invention relates to a packaging suited for heating in
microwave ovens, ovens or double boilers, which is comprised of a
multilayer film material having at least one area that is rendered
permeable when an internal pressure generated by the microwave
heating is exceeded. The invention is characterized in that this
area is formed by a microperforation that is covered by a label or
by a hot stamping film or by a varnish coating.
Inventors: |
Kastner; Friedrich;
(Grieskirchen, AT) ; Zoister; Stefan; (Perg,
AT) ; Madai; Gyula; (Budapest, HU) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
1030 15th Street, N.W.,, Suite 400 East
Washington
DC
20005-1503
US
|
Family ID: |
37562084 |
Appl. No.: |
11/989430 |
Filed: |
July 26, 2006 |
PCT Filed: |
July 26, 2006 |
PCT NO: |
PCT/EP2006/007345 |
371 Date: |
February 27, 2008 |
Current U.S.
Class: |
206/459.5 |
Current CPC
Class: |
B65D 2205/02 20130101;
B65D 2205/025 20130101; B65D 77/225 20130101; B65D 81/3461
20130101; B65D 2581/345 20130101 |
Class at
Publication: |
206/459.5 |
International
Class: |
B65D 90/00 20060101
B65D090/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2005 |
AT |
A 1257/2005 |
Claims
1) Packaging suitable for heating in the microwave, oven, or water
bath consisting of a multi-layered film material having at least
one area which becomes permeable when the internal pressure
produced by the microwave heating is exceeded characterized by this
area being produced by a microperforation covered by a label, hot
stamping film, or a varnish coating.
2) Packaging in accordance with claim 1 characterized by the
microperforated area having, for example, the shape of a circle,
rectangle, square, trapezoid, triangle, an ellipsis or
semi-ellipsis, but also the shape of specific marks, symbols,
letters, text, and the like.
3) Packaging in accordance with one of claims 1 or 2 characterized
by the microperforation being shaped like a circle, a slit, a
rectangle, a square, and the like.
4) Packaging in accordance with one of claims 1 to 2 characterized
by the microperforation being shaped like a logo.
5) Packaging in accordance with one of claims 1 or 2 characterized
by the microperforated area having a varnish coating based on a
mixture or a polyester acrylate, or epoxyacrylate colophonium,
acrylate, alkyde, melamine, PVA, PVC, isocynate, urethane systems,
butadiene, a styrene system, or their copolymers.
6) Packaging in accordance with claim 3 characterized by the
varnish coating, the label, or the hot stamping film containing an
energy-absorbing additive.
7) Packaging in accordance with one of claims 1 to 4 characterized
by intermediate layers being provided between the external and
internal layers.
8) Packaging in accordance with claim 5 characterized by the
intermediate layers being barrier layers, absorber layers, browning
layers, [layers which provide] flexibility, or strength, or
rigidity, and/or printed layers.
9) Packaging in accordance with one of claims 1 to 6 characterized
by the side of the interior layer facing the interior space of the
packaging having an absorber layer which is fixed in place by a
membrane with a rupture site.
10) Packaging in accordance with one of claims 1 to 7 characterized
by different markings being applied to the area of the
microperforation which show a definite change in the optical image
after the valve is opened.
11) Film material for the manufacture of packagings in accordance
with one of claims 1 to 8.
Description
[0001] The inventions relates to a packaging for foodstuffs,
ready-to-serve meals, animal feed, non-food products like cold-hot
packs, packaged refreshing towels, detergents, cleaning agents, and
the like which is suitable to be used in a microwave, oven, or in a
water bath.
[0002] Foodstuffs or ready-to-serve meals are known which are
heated in their packaging, in particular in a microwave, or an
oven, or a water bath.
[0003] Packagings are understood to mean rigid, semi-rigid, or
flexible packagings.
[0004] On account of the expansion of the contents and of air and
gases associated with the heating up, such packagings tend to
rupture or burst.
[0005] To a limited degree, this danger can be reduced by using
packagings which definitely have larger dimensions than the volume
of the contents.
[0006] Furthermore, the water contained in the contents is
converted to steam during heating. This steam cannot escape from
the usual sealed packagings, or only with difficulty; therefore,
ready-to-serve meals cannot be heated in such a way that they are
crispy.
[0007] From EP 661 219 B1 a packaging is known which has a
multi-layer structure. In this structure, the exterior layer and
the interior layer can be non-heat fused together with one another.
Moreover, a connecting part is provided through which the exterior
layer is connected to an interior layer by a connecting part and an
area in which the exterior layer is not connected to the interior
layer so that a communicating passage is formed which has an outlet
opening to the exterior space.
[0008] The interior side is designed with aids which connect the
interior space with the communicating passage. The outlet opening
has an adhesive layer which opens when a specific pressure in the
interior space of the packaging is exceeded.
[0009] As a result, a specific excess pressure is guaranteed in the
packaging when it is heated in the microwave. In addition, a
controlled escape of the excess pressure is guaranteed from a
specific value on.
[0010] From WO 03/051745 a packaging of an unopened heatable
material, in particular heatable in a microwave, is known which has
at least one sealing area which becomes permeable locally when a
specific internal pressure is exceeded, this sealing area having at
least one passage section which forms a control valve for the
packaging contents, and which is designed as a channel-like
passage, and which includes a point facing the interior of the
packaging, this point preferably being sealed.
[0011] A disadvantage of this valve design is that the valve is not
only opened from the interior by excess pressure induced during
heating but is also easily opened as a result of mechanical
pressure. Furthermore, the dimensions of the passage channel cannot
be designed precisely. Moreover, the possibility exists that during
manufacture, autoclaving, sterilization, storage, or heating,
contents migrate from the packaging into the valve pushing open the
valve prematurely and exiting into the surrounding space of the
microwave oven. However, it is also possible that the valve become
clogged with the infiltrating contents and the steam cannot escape
to the required degree. In addition, the valve must be located in
the area of a sealing seam and cannot be placed freely in another
area of the film.
[0012] From WO 04/13015 A a packaging is known which has an
absorber to absorb the moisture escaping during heating, which
allows for the preparation of crispy food. Without a valve through
which the excess steam can escape, however, the absorber is used up
too quickly.
[0013] None of these packagings can be resealed once they are
opened and, therefore, cannot be stored, for example in the
refrigerator, after having been opened and part of the contents
removed.
[0014] The purpose of the invention was to make available a
packaging suitable for heating in the microwave, oven, or water
bath in which, on the one hand, it is possible to develop a
specific excess pressure and to allow the steam to escape in a
controlled manner and it is possible to cook the food with
steam.
[0015] Therefore, the object of the invention is a packaging
suitable for heating in the microwave, oven, or water bath
consisting of a multi-layer film material having at least one area
which becomes permeable when an internal pressure produced by the
heating is exceeded characterized by this area being formed by a
microperforation which is covered by a hot stamping film or a
varnish coating.
[0016] The microperforation can be produced in the film material by
means of needles or a laser beam.
[0017] The shape of the microperforated area can vary and, for
example, be a circle, rectangle, square, trapezoid, triangle, an
ellipsis or semi-ellipsis but also be shaped like specific marks,
symbols, lines, letters, text, and the like.
[0018] The shape of the microperforation can be a circle, slit,
rectangle, square, and the like.
[0019] The arrangement of the circles, slits, rectangles, or
squares and the like of the microperforation can, if appropriate,
form a logo and the like.
[0020] In this regard the dimensions of the microperforation can be
10 .mu.m to 1.5 mm in length and/or width, preferably 50 .mu.m to 1
mm. If necessary, a further film can be laminated--at least in the
microperforated area--over a varnish or adhesive varnish which
softens when exposed to heat, this further film having
mircroperforations offset to the first microperforations.
[0021] This results in a temporally and locally offset opening of
the microperforated valve.
[0022] The microperforated valve can be placed at any spot on the
packaging.
[0023] The microperforated area is covered with an adhesive label,
a hot stamping film and/or a varnish coating.
[0024] The varnish coating can be a watery as well as solid varnish
systems, in particular also a varnish system based on polyester
acrylate or epoxyacrylate colophonium, acrylate, alkyde, melamine,
PVA, PVC, isocynate, urethane systems, butadiene, a styrene system,
or their copolymers, which can be hardened conventionally or
reactively (by chemical or radiation hardening).
[0025] If necessary, the varnish or the label covering the
microperforation, the hot stamping film or varnish coating also
contains energy-absorbing additives, like metallic additives,
graphite, energy-absorbing pigments or particles and the like. In
particular, particles and pigments are considered whose molecular
components resonate and are set into thermal vibration as a result
of the incident microwave radiation or with which currents are
induced by the incident microwave radiation.
[0026] These include especially pigments or particles which contain
molecular water, like water glass or zeolites. Furthermore, known
conductive polymers can also be used.
[0027] The varnish coating can be applied to the microperforated
area by known coating or printing processes, by gravure printing,
flexographic printing, screen printing, offset printing, digital
printing, smooth rolling, half-tone or line screen processes--in
each case running in the same direction or in the opposite
direction--curtain coating and the like.
[0028] When heated in the microwave, the varnish layer, the
adhesive layer of the label, or the hot stamping film over the
microperforated area becomes brittle and, therefore, permeable; the
steam produced can escape.
[0029] Cooling of the packaging results in the microperforation
being resealed by the cooling varnish.
[0030] In addition, the microperforation can be resealed by
mechanical pressure, for example by pressing the adhesive label on
the microperforation again. In this regard the label can be
equipped with an adhesive coating which adheres firmly in a
specific area outside of the microperforation during heating but
loosens in the area of the microperforation during heating. When
cooled, this adhesive coating becomes capable of adhering again,
and the label can be reconnected to the film by means of mechanical
pressure.
[0031] Consequently, the packaging can be resealed and, for
example, stored until it is used again, if necessary under
refrigeration.
[0032] The film material of the packaging consists of two or more
layers.
[0033] The external layer preferably consists of a film made of
plastic, for example polyester, like oriented PET, amorphous PET,
polyolefines, like polypropylene, cast PP, blown, stretched,
biaxially stretched PP films, or polyethylene, polystyrene,
polycarbonate, cellophane, polyamide, polyvinylchloride, or their
copolymers. However, co-extruded or laminated plastic composite
films or composites with paper can be used. Moreover, it is
possible to use coated films, biologically degradable films,
aluminium foils, and the like. The thickness of the external layer
is preferably 8-200 .mu.m.
[0034] The inner layer preferably consists of a sealable medium,
for example of plastic films made from polyolefines, like
polyethylene, polypropylene, from EVOH, EVA, and/or their
copolymers or terpolymers, polystyrene, polycarbonate, cellophane,
polyamide, polyvinylchloride. However, the inner layer can also be
produced by an extrusion coating or varnishing the external film
with one of the plastics named.
[0035] The thickness of the inner layer is preferably 0.5-100
.mu.m.
[0036] If necessary, intermediate layers can be situated between
the external and internal layers. Such intermediate layers can be,
for example, barrier layers, like aluminium oxide layers or
silicone oxide layers, organic barrier layers, like polyamide
layers, absorber layers, for example gas absorber layers, like
O.sup.2, CO.sup.2 absorber layers, water-vapour-absorber layers,
ethylene absorber layers, imprinted layers, layers which provide
increased flexibility, or strength, or stiffness, and the like.
[0037] The entire laminar composite of the inventive packaging can,
if necessary, comprise several intermediate layers and combinations
of these intermediate layers, in which case the layers either
adhere well to each other or can be connected to one another by
adhesive aids, like adhesive agents.
[0038] In order to identify the opening of the microperforated
valve, a marking can be applied around this area on the film
material and covering material which clearly changes its appearance
upon the area becoming permeable.
[0039] For example, two differently coloured markings can be
applied which produce a mixed colour in the covered state. After
the valve is opened, the two layers separate and the pure colours
appear.
[0040] Furthermore, in order to identify the opening of the valve,
partial information can be applied to the separating layers which
then becomes comprehensible information after the valve is opened,
for example text, e.g. "open" and the like. This can be done using
auxiliary layers with different adhesive strengths.
[0041] In addition, one or more absorber layers for the water
vapour resulting during heating can be provided on the side of the
interior layer facing the interior of the packaging. For example,
hydrophilic polymers, like EVA, polymers with high zeolite
loadings, silica gel, fleece or fabrics which have embedded
hydrophilic polymers, fleece or fabrics coated with zeolite are
considered as such absorber layers.
[0042] In one embodiment the absorber layer can be applied on the
interior layer using pressure processes.
[0043] However, the absorber layer can also be fixed to the
interior layer with a thin sealing layer or membrane. The fixing
layer or the membrane can have a rupture point. When a specific
pressure is exceeded in the packaging, the membrane expands and
tears open at the rupture site, as a result of which the absorber
layer is exposed and the resulting water vapour can be
absorbed.
[0044] Under such a membrane, perhaps additional membranes,
aromatic materials, for example smoked materials or the like, can
be present in place of the absorber layer which are then released
by the opening of the membrane when a specific pressure is
exceeded.
[0045] In order to produce a characteristic aroma, aromatic
materials in capsules can also be placed in the valve area and
released when the valve opens.
[0046] Moreover, the packaging can have an opening aid, preferably
resealable, for example a laser perforation, a tear string, in
which case this opening can then be reclosed by applying a
label.
[0047] When applying a laser perforation, both the microperforation
of the valve as well as the opening aid can be applied by
modulating the laser energy in an operational cycle.
[0048] However, zipper-like or sliding-closure-like devices, which
are resealable, are also opening options.
[0049] The packaging can be designed in the shape of a bag, a
purse, a stand-up bag, a tray, a sachet, a pouch, or of a sealing
film for containers.
* * * * *