[0001] The present invention relates to a foodstuff base, intended particularly for consumer
packages of meat, and which is made from fibre-based material formed into a basin.
[0002] A general way of packaging foodstuffs in consumer packages to be sold in supermarkets
is to place a product on a base formed into a basin and then to enclose it with a
transparent plastic film. Foamed plastic has usually been used as the material for
the base. A drawback of plastic is however that it is nearly undecomposable in dumping
areas. In addition, plastic lacks any absorption ability, which is a drawback in packages
of such foodstuffs from which liquid is extracted. Particularly for packages of fresh
meat, a plastic base is unappropriate.
[0003] The absorption problem has been avoided in a foodstuff base known in the art, in
which two layers of expanded polystyrene have been placed on top of each other, the
upper one of which being perforated, and wherebetween an absorption layer made of
paper or other fibre material has been inserted. The essentially plastic base is not,
however, biodegradable.
[0004] The biodegradability requirement is met by a prior art foodstuff base pressed from
mass by so-called egg-cell technique, typically composed of fibres and microwaxes.
Such base is excellently appropriate for packages intended for fruit and other dry
foodstuffs. On the contrary, from moist foodstuffs said base absorbs water, as a result
of which the base becomes soft, loses its strength and becomes unattractive. Endeavours
have been made to reduce the wettability of a base pressed from such mass by means
of various adhesives, but for instance for packages of fresh meat, no success has
been achieved when trying to provide a well functioning base material.
[0005] The object of the present invention is to provide a fibre-based foodstuff base in
which the above-mentioned drawbacks of the bases known in the art have been eliminated.
A special aim is to produce a compostable, absorbable base which is appropriate for
packaging fresh meat extracting meat fluid. Characteristic of the base of the invention
is that it comprises a laminated structure, including an upper paper or carton layer
provided with a non-adhering, liquid-permeable surface, a block layer thereunder made
of polymer and impermeable to any liquid, and a lower carton layer thereunder forming
a stiffener.
[0006] In a base of the invention, the upper paper or carton layer serves as an absorption
layer to absorb liquid extracting from a produce, such as meat, into itself so that
no liquid remains lying unattractively on the base. The blocking layer made from polymer
and located under the absorption layer in turn prevents penetration of the liquid
deeper into the base structure. The second carton layer underneath the block layer
thus remains dry, and, on the whole, the package remains, despite the absorption of
liquid, rigid and esthetically immaculate. The material of the base of the invention
is recyclable, it can be destroyed by burning and being composed of disintegratable
polymer layers, it becomes decomposed in composts and dumping sites.
[0007] A requirement set for the surface of the base according to the invention is that
it allows liquid therethrough to absorb into the absorption layer made of paper or
carton and that no moist foodstuff such as fresh meat will adhere to it. Alternatives
in the design are either sealing by calendering the surface of the upper paper or
carton layer acting as the absorption layer or providing said surface with polymer
coating with liquid-permeable apertures or pores. With either of the ways a surface
can be provided, which, as regards non-adherence, corresponds to state of art plastic
foodstuff bases.
[0008] A porous, liquid permeable polymer coating can be provided using a so small amount
of polymer that it is simply not enough to create a uniform, impermeable coating film.
For instance, in a film which contains about 1 to 10 g/m², preferably about 5 to 10
g/m², of polyethylene, micropores are left which suffice to allow liquid to be absorbed
in the absorption layer. Alternatively, the polymer coating can be applied on the
base intentionally so that the coating film will not be uniform but liquid permeable
spots are left therein. The coated and uncoated areas of the base may in such instance
have a regular shape, e.g. so that the openings in the coating are mutually of the
same size and at a regular spaces from one another, or so that the coating is applied
on the base as raster-like pads mutually of same size and at regular distance from
each other. In order to provide non-adherence, the coating should, however, cover
at least 10 per cent, preferably about 30%, most preferably at least 50% of the surface
area of the base.
[0009] According to an advantageous embodiment of the invention, the openings without any
polymer coating on the surface of the base are continued into the carton layer underneath,
penetrating it as far as to the polymer block layer. Herewith, the contact surface
between the liquid and the carton layer can be increased and in that way absorption
intensified, without having to reduce the proportion of the polymer-coated area on
the base surface.
[0010] In a foodstuff base according to the invention, especially in one intended for consumer
packages of fresh meat, the quantity of polymer coating may vary e.g. in the range
1 to 30 g/m², preferably 5 to 30 g/m², the weight of the upper paper or carton layer
being e.g. in the range 20 to 400 g/m², preferably 60 to 400 g/m², and most preferably
about 200 g/m², the weight of the liquid-impermeable block layer, which can be of
the same polymer material as the coating, varying e.g. from 5 to 30 g/m², preferably
10 to 30 g/m², and the weight of the lower carton layer, serving as the stiffener,
may vary e.g. in the range 200 to 400 g/m², preferably about 200 g/m². Especially
for a large-size base, even more massive carton layers can advantageously be used.
[0011] The invention is described below more in detail with the aid of examples, by referring
to the accompanying drawing, in which
- Fig. 1
- presents a basin-like foodstuff base in oblique top view,
- Fig. 2
- presents a base design according to the invention, in which the base bottom is calendered,
- Fig. 3
- presents another base design according to the invention, in which the base is provided
with thin polymer coating,
- Fig. 4
- presents a further base design according to the invention, in which the base surface
includes openings penetrating the polymer layer and the carton layer thereunder, section
IV-IV from Fig. 5,
- Fig. 5
- presents the base of Fig. 4 in top view,
- Fig. 6
- presents a base design according to the invention provided with polymer coating as
pads separated in raster-like fashion from each other, section VI-VI of Fig. 7, and
- Fig. 7
- presents the base of Fig. 6 in top view.
[0012] The foodstuff base 1 presented in Fig. 1, which is particularly intended for consumer
packages of fresh meat for sale especially in supermarkets, has been produced from
a fibre-based, laminated sheet material formed by pressing into a basin. The base
1 comprises a substantially uniform bottom 2 and obliquely upward directed margins
3.
[0013] Fig. 2 presents an example of the layer structure of the material of base 1 as shown
in Fig. 1. The structure comprises an upper carton layer 5 calendered on surface 4,
thereunder a block layer 6 made of polymer, and lowermost a lower carton layer 7.
The layers 5 and 7 may be made of an ordinary carton manufactured in a carton-making
machine, the weight thereof being advantageously about 200 g/m². The weight of the
block layer 6, which can be water-impermeable, is e.g. 15 g/m², and as the material
thereof, e.g. polyethylene, polypropylene, polyethylene terephtalate as well as various
varnishes can be considered, such acrylate-based varnishes (e.g. varnish No. 42988
produced by Roymal Inc. or DC 2000 and DC 2001 products by Dussek Campbell Ltd.) and
styrene varnishes. The surface 4 of the upper carton layer 5 has with the aid of calendering
accomplished with heat and pressure been so sealed that a product entering against
the surface, such as fresh meat, will not readily adhere thereto. The calendered surface
is, however, sufficiently porous so that the meat fluid extracting from the meat,
being mostly water, is enabled to absorb into the upper carton layer 5 acting as the
absorption layer. The polymer block layer 6 prevents water from absorbing into the
lower carton layer 7 which therefore remains dry and supported by which the base remains
rigid in use.
[0014] The embodiment of the invention presented in Fig. 3 differs from the one shown in
Fig. 2 only in that instead of calendering the surface of the upper carton layer 5,
the base material has been provided with thin polymer coating layer 8. The weight
of the coating layer 8 is 1 to 10 g/m², and the same materials are suitable for its
material as in the block layer 6. In addition, from among appropriate coating materials,
acrylate varnish Rebarco EP 716 by Company Raisio Yhtymä can be mentioned as an example.
Coating layer 8 can be applied on the carton 5 as aqueous or dissolvent dispersion
from which the intermediate agent is removed after application by evaporation. The
essential feature is that micropores are left in the thin coating layer 8 through
which liquid extracted from the packaged product, such as meat fluid, is enabled to
absorb into the carton layer 5 thereunder.
[0015] Figs. 4 and 5 present an embodiment of the invention in which, deviating from Fig.
3, the polymer coating layer 8 is thicker, advantageously about the same thickness
as the block layer 6. The mass of the coating layer 8 is now about 10 to 30 g/m².
Openings 9 have been made in the coating layer 8, extending through the upper carton
layer 5 serving as absorption layer, into the polymer block layer 6. The openings
9 are round in shape, being about 1 to 5 mm in diameter, preferably 3 to 4mm, and
they have been arranged in the base material in regular longitudinal and transverse
rows as shown in Fig. 5, at about 1 cm mutual spaces. The openings 9 lead liquid extracted
from a packaged product through the otherwise liquid-impermeable coating layer 8 into
the absorbing carton layer 5. It is enough, with a view to the invention, that there
are openings 9 in the area of the bottom 2 of the base 1, although, when producing
bases by cutting and pressing from homogenous sheet material already provided with
openings therein, the pattern produced by openings may, of course, cover also the
marginal areas 3 of the base.
[0016] In the application of the invention presented in Figs. 6 and 7 the polymer coating
is applied on the surface of the base material as pads 10 separated in raster-like
fashion from each other. As regards the other layers 5,6,7 of the material, this embodiment
corresponds to that presented in Fig. 3. The pads 10 are round, about 1 to 10 cm in
diameter, and as shown in Fig. 7, they are placed as regular longitudinal and transverse
rows on the surface of the upper carton layer serving as the absorption layer. The
size and mutual distances of the pads 10 are so selected that they cover at least
about 30%, preferably at least 50% of the surface of the base. The polymer material
of the pads prevents now the product, such as fresh meat, from adhering onto the surface
of the base at the same time as the liquid extracting from the product is enabled
to penetrate between the pads and absorb into the carton absorption layer 5 thereunder.
The polymer coating used in pads may, depending on the production technique, cover
either the bottom 2 of the base or the base surface in its entirety.
[0017] It is obvious to a person skilled in the art that various embodiments of the invention
are not confined to the examples presented above, and they may vary within the scope
of the accompanying claims. For instance, the embodiment as in Fig. 4 can be modified
so that the apertures 9 are arranged only in the polymer coating layer 8, without
continuing into the paper or carton absorption layer 5 thereunder. This is advantageous
particularly if the absorption layer 5 is made of paper, in other words, it is substantially
thinner than that in Fig. 4. The apertures 9 of the coating layer 8 can be made with
perforated polymer film laminated onto the surface of the base material which is otherwise
finished at the same time as the material is pressed into a basin. The holes in the
film maintain their shape during lamination and form on the surface of the finished
base the desired water-permeable apertures. It is furthermore possible to add more
layers on the laminated base materials presented, such as paper to be attached to
the base bottom for printing.
1. A foodstuff base (1), which is especially intended for consumer packages of meat and
is comprised of fibre-based material formed into a basin, is characterized in that
the base comprises a layer structure including an upper paper or carton layer (5)
provided with non-adhering, liquid-permeable surface (4,8,10), thereunder a liquid-impermeable
block layer (6) made of polymer, and under said layer a lower carton layer (7) producing
a stiffener.
2. Foodstuff base according to lcaim 1, characterized in that the surface (4) of the
upper paper or carton layer is calendered to be non-adhering.
3. Foodstuff base according to claim 1, characterized in that the upper paper or carton
layer (5) is provided with polymer coating (8,10) provided with liquid-permeable apertures
(9) or pores.
4. Foodstuff layer according to claim 3, characterized in that the upper paper or carton
layer (5) has about 1 to 10 g/m² of coating essentially as a uniform layer (8) provided
with micropores.
5. Foodstuff base according to claim 3, characterized in that the coating (8) has apertures
(9) with a diameter of about 1 to 5 mm, preferably about 3 to 4 mm.
6. Foodstuff base according to claim 5, characterized in that the apertures (9) of the
coating also penetrate the carton layer (5) thereunder.
7. Foodstuff base according to claim 3, characterized in that the polymer coating is
applied on a paper or carton layer (5) as pads (10) separated in raster-like fashion
from each other.
8. Foodstuff base according to any one of claims 5 to 7, characterized in that the coating
(8,10) covers at least about 30%, preferably at least about 50% of the paper or carton
layer (5) underneath.
9. Foodstuff base according to any one of claims 5 to 8, characterized in that the liquid-permeable
polymer coating (8,10) covers the area of the basin bottom (2).
10. Foodstuff base according to any one of claims 3 to 9, characterized in that the weight
of the polymer coating (8,10) is about 1 to 30 g/m², the weight of the upper paper
or carton layer (5) is about 20 to 400 g/m², of the block layer (6) being about 5
to 30 g/m², and the weight of the lower carton layer (7) being about 200 to 400 g/m².