[0001] The invention relates to a new absorbent pad for use in the packaging of food products,
to the process for the manufacture thereof, to its use in the manufacture of food
packages and to the packages thus obtainable.
BACKGROUND OF THE INVENTION
[0002] It is common practice in retail stores to display certain types of foods, such as
meat, poultry and some vegetables, in individually wrapped containers. Examples of
such containers are trays overwrapped by a transparent plastic film and transparent
bags. The use of these types of packages offers the advantage to the consumer of seeing
and inspecting the packaged product. However, in the case of liquid containing products,
such as meat or poultry, the liquids exuded from the food can create a negative visual
impression on the consumer. Furthermore, the presence of these liquids in direct contact
with the food product may promote the growth of bacteria inside the package. These
problems have been generally overcome by the use of absorbent pads, which are introduced
in the package between the product and the bottom of the container.
[0003] Several absorbent pads have been proposed which comprise a mat of an absorbent material
enclosed between two sheets of plastic material, which are sealed along their edges.
For instance, US Patent 5,055,332 and US Patent 6,270,873 both disclose absorbent
pads for food products including an upper and lower plastic film, at least one of
which is perforated, and an intermediate absorbent layer. However, these types of
absorbent pads have some disadvantages. The absorbed liquid is visible through the
plastic sheet of the pad partly due to the perforations and, unless it is glued to
the bottom of the container, the pad tends to stick to the packaged product creating
a negative impression on the consumer who has to manually remove it. A possible way
to eliminate the latter problem is described in FR-A-2,687,381, which discloses a
mat of absorbent material held in place at the bottom of a packaging container by
means of a film of plastic material glued to the bottom of the container, the film
being preferably perforated. All these types of pad are sometimes difficult to handle
in automatic padding operations, their excessive flexibility making it difficult to
correctly position the pad in a container, such as a tray or a bag.
[0004] A way to solve some of the problems outlined above is described in DE 90 13 898.8U,
which discloses an absorbent pad, covering only part of the bottom of the tray, comprising
two plies, one of an absorbent material and the other of a water-impermeable support,
made of a material chosen from the group of PE, PP or PS which is preferably foamed
and with a thickness comprised from 120 to 300 µm. The water-impermeable support covers
completely the absorbent material hiding the absorbed liquid from the sight of the
consumer. Furthermore the support and the absorbent layer are sealed or glued to each
other and to the bottom of the tray to avoid any displacement. However this solution
has two main drawbacks. First of all, with such an arrangement when the tray is in
a vertical or inclined position the absorption of the liquids exuded by the product
is limited, depending on how smaller is the pad with respect to the tray bottom, and
therefore the liquid tends to pool in the corner of the tray with obvious disadvantages.
Secondly, since the pad is bound to the bottom of the tray through the absorbent material,
once this has absorbed the liquids exuded from the product, it swells causing the
detachment of the pad. An improved technical solution with respect to DE 90 13 898.8U
is proposed by EP-A-609,184, which discloses an absorbent pad comprising two plies,
i.e, a layer of an absorbent material laid on the bottom of a tray separated from
the product by a support, said pad forming with the sides of the tray a drain encircling
the pad. Said pad can be either glued to the bottom of the tray or it can be secured
by a series of clips protruding from the sides of the tray. Similarly, FR-A-2,749,567
discloses a tray having an internal ledge which is profiled to present an overhang
projecting over the base of the tray to form a structure which grips and centres a
pad of absorbent material on the base of the tray. The above-mentioned solutions involve
the use of special moulds for producing a tray with suitable clips requiring additional
expenses in the manufacturing of the tray.
[0005] The need therefore still exists for a pad, which suitably absorbs and hides the drip
and that can be easily manufactured and handled in automatic padding operations.
[0006] A first objective of the present invention is therefore to provide an absorbent pad
that may efficiently absorb and hide from the sight of the consumer any type of liquid
present in a food package.
[0007] Another objective is to provide a pad that can be conveniently handled and positioned
during packaging operations.
[0008] Still another objective of the invention is to provide a pad that can be reliably
secured to a container without requiring special moulding tools for the preparation
of the container, thus avoiding the risk of removing the pad together with the product.
SUMMARY OF THE INVENTION
[0009] A first object of the present invention is a rigid or semi-rigid absorbent pad comprising
a rigid or semi-rigid support made of a liquid impermeable material having two flat
opposing surfaces, and a mat of liquid absorbent material laminated over only one
of the surfaces of the rigid or semi-rigid support, characterized in that,
- the mat of liquid absorbent material has a surface smaller in size than that of the
rigid or semi-rigid support thus leaving exposed a portion of the surface of the support
onto which it is laminated, and
- means are present in said exposed portion of the surface of the support to bind the
pad to the container,
provided said means do not encircle the mat of liquid absorbing material in a continuous
manner.
[0010] A second object of the present invention is a process for the manufacture of a pad
according to a preferred embodiment of the present invention.
[0011] A third object of the present invention is a composite web for the production of
an absorbent pad according to the present invention, said composite web being wound
into a roll.
[0012] A further object of the present invention is a food package comprising an absorbent
pad according to the present invention and a container.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
Fig. 1 is a perspective view of a pad of the present invention;
Fig. 2 is a representative schematic of a process line for making a pad according
to one embodiment of the present invention;
Fig. 3 is a representative schematic of a process line for making a pad according
to a further embodiment of the present invention;
Fig. 4 is a top view of a package of the present invention;
Fig. 5 is a section along the line I-I in Figure 4.
DETAILED DESCRIPTION OF THE INVENTION
[0014] According to a first aspect of the invention there is provided an absorbent pad comprising
a rigid or semi-rigid support made of a liquid impermeable material having two flat
opposing surfaces, and a mat of liquid absorbent material laminated over only one
of the surfaces of the rigid or semi-rigid support, characterized in that,
- the mat of liquid absorbent material has a surface smaller in size than that of the
rigid or semi-rigid support thus leaving exposed a portion of the surface of the support
onto which it is laminated, and
- means are present in said exposed portion of the surface of the support to bind the
pad to a container,
provided said means do not encircle the mat of liquid absorbing material in a continuous
manner.
[0015] As used herein, the phrase "rigid or semi-rigid" refers to a material that does not
deform, bend or loose its shape when deprived of support.
[0016] Preferably the rigid or semi-rigid support of liquid impermeable material employed
for the pad of the present invention is made of one or more layers of a thermoplastic
material chosen from the group comprising polyolefins, polyesters, polystyrenes, PVC,
poly(lactic acid) and the like materials.
[0017] Suitable polyolefins include ethylene homo- and co-polymers and propylene homo- and
co-polymers. As used herein, the term "copolymer" refers to a polymer derived from
two or more types of monomers, and includes terpolymers. Ethylene homopolymers include
high density polyethylene (HDPE) and low density polyethylene (LDPE). Ethylene copolymers
include ethylene/alpha-olefin copolymers and ethylene/unsaturated ester copolymers.
Ethylene/alpha-olefin copolymers generally include copolymers of ethylene and one
or more comonomers selected from C
3 to C
20 alpha-olefins, such as 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene
and the like.
[0018] Ethylene/alpha-olefin copolymers generally have a density in the range of from about
0.86 to about 0.94 g/cc. The term linear low density polyethylene (LLDPE) is generally
understood to include that group of ethylene/alpha-olefin copolymers which fall into
the density range of about 0.915 to about 0.94 g/cc and particularly about 0.915 to
about 0.925 g/cc. Sometimes linear polyethylene in the density range from about 0.926
to about 0.94 is referred to as linear medium density polyethylene (LMDPE). Lower
density ethylene/alpha-olefin copolymers may be referred to as very low density polyethylene
(VLDPE) and ultra-low density polyethylene (ULDPE). Ethylene/alfa-olefin copolymers
may be obtained by either heterogeneous or homogeneous polymerization processes. Heterogeneous
processes afford products with relatively wide molecular weight distribution (M
w/M
n greater than 3.0) and composition distribution. Heterogeneous copolymers typically
contain a relatively wide variety of main chain lengths and comonomer percentages.
On the other hand, homogeneous processes afford products with relatively narrow molecular
weight distribution (M
w/M
n less than 3.0) and composition distribution. Homogeneous polymers are structurally
different from heterogeneous polymers, in that homogeneous polymers exhibit a relatively
even sequencing of comonomers within a chain, a mirroring of sequence distribution
in all chains, and a similarity of length of all chains. Heterogeneous polymers may
be prepared, for instance, with Ziegler-Natta catalysts. On the other hand, homogeneous
polymers are typically prepared using metallocene or other single-site catalysts.
[0019] Another useful ethylene copolymer is ethylene/unsaturated ester copolymer, which
is the copolymer of ethylene and one or more unsaturated ester monomers. Useful unsaturated
esters include vinyl esters of aliphatic carboxylic acids, where the esters have from
4 to 12 carbon atoms, such as vinyl acetate, and alkyl esters of acrylic or methacrylic
acid, where the esters have from 4 to 12 carbon atoms.
[0020] Useful propylene copolymers include propylene/ethylene copolymers (EPC), which are
copolymers of propylene and ethylene having a majority weight percent content of propylene,
and propylene/ethylene/butene terpolymers (EPB), which are copolymers of propylene,
ethylene and 1-butene.
[0021] As used herein the term "polyesters" refers to polymers obtained by the polycondensation
reaction of dicarboxylic acids with dihydroxy alcohols. Suitable dicarboxylic acids
are, for instance, terephtalic acid, isophtalic acid, 2,6-naphthalene dicarboxylic
acid and the like. Suitable dihydroxy alcohols are for instance ethylene glycol, diethylene
glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of useful
polyesters include poly(ethylene 2,6-naphtalate), poly(ethylene terephtalate), and
copolyesters obtained by reacting one or more dicarboxylic acids with one or more
dihydroxy alcohols.
[0022] As used herein the term "polystyrenes" refers to homo- and co-polymers of styrene.
Useful styrene copolymers include styrene/butadiene rubbers (SBR), styrene/butadiene
block copolymers (SBS), styrene/ethylene/butadiene copolymers (SEBS), styrene/isoprene
block copolymers (SIS) and the like.
[0023] Typically, the rigid or semi-rigid support of the liquid impermeable material has
a thickness comprised between 100 microns to 5 mm, preferably from 200 microns to
4 mm, and even more preferably from more than 250 microns to 3 mm. Thicknesses lower
than 100 microns, e.g. down to 50, 60, 70, 80, 90 microns, may also be employed, depending
on the modulus of the particular resins used, but in most cases they would not offer
a sufficient rigidity for a reliable handling and positioning of the pad in automatic
padding operations. Thicknesses higher than 5 mm would make the cost of the pad excessive
without providing beneficial effects.
[0024] In one embodiment of the present invention the rigid or semi-rigid support of the
pad is an extruded monolayer material. Preferably the support is foamed or contains
inorganic fillers, such as talc, TiO
2, calcium carbonate and the like, so to be rendered opaque, therefore hiding the absorbed
liquid from the sight of the consumer.
[0025] In a preferred embodiment of the present invention the rigid or semi-rigid support
of the pad consists of at least two layers: an upper layer, which is in contact with
the product in the final package, that confers rigidity to the support and a lower
layer, which is bound to the mat of liquid absorbent material. Typically the upper
layer is thicker than the lower layer, the ratio of the two thicknesses depending
on the modulus of the plastic materials employed. Preferably the upper layer of the
support is foamed or contains inorganic fillers, such as talc, TiO
2 and the like. Even more preferably, the upper layer of the support is made of the
same material as the container with which it forms the final package, therefore not
only hiding the absorbed liquid but also being indistinguishable from the container
at first sight.
[0026] Preferably the lower layer is made of a material chosen from the group of polyolefins,
suitable for binding with the mat of liquid absorbent material. Preferred materials
are copolymers of ethylene and unsaturated esters, such esters of aliphatic carboxylic
acids and alkyl esters of acrylic or methacrylic acid, more preferably vinyl acetate.
Other layers can be present between said upper and lower layers. For instance a tie
layer might be employed to improve the adhesion between the upper and the lower layer
or additional layers might be employed to modulate the mechanical properties of the
whole support. The support can be produced either by extrusion, co-extrusion or by
heat- or glue-lamination.
[0027] Non-limiting examples of suitable supports for the pad of the present invention,
particularly in conjunction with foamed polystyrene trays, are laminates of a foamed
polystyrene sheet (having a thickness between 0.5 to 2 mm) with a multilayer film
comprising an ethylene/vinyl acetate copolymer outer layer, that is the layer that
will be bonded to the absorbent mat, and another outer layer comprising a polymeric
material that could be easily heat-laminated to the foamed polystyrene sheet, such
as a linear low or very low density polyethylene, an anhydride modified linear low
or very low density polyethylene, a styrene-butadiene block copolymer, a styrene-butadiene
rubber or mixtures thereof. The thickness of said film heat-laminated to the foamed
polystyrene sheet may typically range between 20 microns to 100 microns.
[0028] Suitable absorbent mats for the pad of the present invention comprise fibers or fiber
assemblies made, for instance, of cellulose pulp, rayon, naturally occurring materials,
synthetic fibers with hydrophilic surface treatments and the like. Such fibers are
typically arranged in the form of fluff wadding, tissue, paper or non-woven sheet
material. Preferably the absorbent mat is composed of an airlaid or dry-formed web
of fibers, which can be bonded either by addition of a latex spray or by softening
or partially melting thermoplastic fibers present in the web. Preferably super-absorbent
polymers are added to the fiber core. As used herein the term "super-absorbent polymer"
refers to one or more hydrocolloid materials capable of absorbing many times their
dry weight of water. In a preferred embodiment, the absorbent mat of the present invention
is made of a material chosen from the group of super-absorbent non-woven materials.
Examples of preferred non-woven super-absorbent materials are the ones produced and
sold by Buckeye Technologies Inc. having a water absorption capacity from about 500
to 7000 g/sqm, preferably from about 700 to 4500 g/sqm, and even more preferably from
about 800 to 3000 g/sqm.
[0029] Said absorbent mat may cover from about 50 % to about 95 %, preferably from about
60 % to about 90 %, and even more preferably from about 70 to about 85 % of the total
surface of the support.
[0030] In the preferred embodiment of the invention, illustrated in Figure 1, the absorbent
mat is laminated to the support 11 as a strip 12 having the same size of the support,
along one of the axes of the support itself, and a size which is from about 50 % to
about 95 %, preferably from about 60 % to about 90 %, and even more preferably from
about 70 to about 85 % of that of the support along the other axis, preferably leaving
two areas of the support uncovered by the absorbent material, said areas forming two
parallel stripes 13a and 13b along the edges of the support, one on each side of the
absorbent mat.
[0031] On the surface of the support that is not covered by the absorbent material (13a
and 13b), there are provided means to bind the pad to the tray.
[0032] In one embodiment this may be achieved by one or more spots of glue that can be applied
just before the tray-padding step. Examples of suitable glues are hot melt adhesives,
i.e. solvent-free thermoplastics-based adhesives that, when heated and in liquid form
(typically above 80°C), are capable of effectively wetting substrate surfaces and
that, after cooling and solidifying adhere firmly to those surfaces. Suitable hot-melt
adhesives are the ones sold by Sealock Ltd, UK under the trade name Sealock H 1125.
[0033] In another embodiment the spots can be of a material that can be applied at an early
stage, in the pad manufacturing process, and be activated, by heat, pressure, or any
other suitable way, at the tray padding stage. Examples of suitable materials are
e.g. pressure sensitive adhesives, energy-curable adhesives, heat-activated adhesives
and the like. The term "pressure sensitive adhesives" refers to adhesives that adhere
to the surfaces of most materials under only light pressure. Typically, pressure-sensitive
adhesives are based on natural and synthetic rubbers in conjunction with modified
rosins or hydrocarbon resins. In addition to rubber, polyacrylates, polymethacrylates,
poly(vinyl ethers) and polyisobutylenes are also used frequently. The term "energy-curable
adhesives" refers to solvent-free adhesive compositions, containing only reactive
low molecular weight, unsaturated resins which can be cured through the use of radiant
energy (electron beam or ultraviolet). The term "heat-activated adhesive" refers to
adhesive materials, which are made sticky by the use of heat and pressure. Suitable
heat-activated adhesives are polyvinylacetate, ethylene-vinyl acetate copolymers,
PVC, polyacrylates, polymethacrylates and many rubber-resin compositions.
[0034] Preferably, instead of spots of adhesive material, the stripes of support surface
void of any absorbent material (13a and 13b) comprise a continuous layer of an adhesive.
Suitable adhesives are for example pressure sensitive adhesives, hot melt adhesives
or heat-activated adhesives.
[0035] The pad of the present invention offers several advantages over the pads of the prior
art: the adhesive spots or stripes are not affected by the absorption of liquid by
the mat of absorbent material and therefore the pad is tightly and reliably secured
to the bottom of the container for the whole life of the end package. At the same
time, the contact between the mat of liquid absorbing material and the liquid is possible
along the sides of the pad, indicated as 14 and 15 in Figure 1, which are not glued
to the bottom of the container.
[0036] The pad of the present invention can be easily obtained by laminating a preformed
support of a size suitable for the desired use to a preformed mat of absorbing material
smaller in size. Alternatively it can be obtained by laminating discrete mats of absorbing
material to a web of support and then suitably cutting the obtained laminate to get
pads of the desired size. Still alternatively the pad of the present invention can
also be obtained by laminating one or more continuous strips of absorbing material
to a web of support material and then cutting the obtained laminate so as to obtain
a pad, such as that illustrated in Fig. 1, where the mat of absorbing material has
the same size of the support in one direction, e.g. the longitudinal direction, while
it is smaller in the other direction, e.g. the transversal direction.
[0037] Said alternative process is particularly advantageous industrially as it is a continuous
process that allows controlling the amount of scrap generated and possibly to generate
scrap that can completely be recycled.
[0038] A second object of the present invention is therefore a process for the preparation
of an absorbent pad according to the present invention, comprising the steps of:
- providing a rigid or semi-rigid web of a liquid impermeable mono or multi-layer material
having a width in the transversal direction equal to that of the final pad or to a
multiple thereof,
- longitudinally laminating at least one stripe of liquid absorbent material onto the
rigid or semi-rigid web, said stripe of liquid absorbent material having a width in
the transversal direction inferior than the width of the final pad, in such a way
that each final pad will have at least one edge which only comprises the rigid or
semi-rigid support and is void of any absorbent material and where means for binding
the pad to the container can be applied, and
- cutting the composite web into single pads.
[0039] In a first embodiment of the above process the composite web is converted into the
single pads at the end of the laminating step by a series of transverse and, as the
case maybe, longitudinal cuts.
[0040] Cutting can be done simultaneously in both the longitudinal and transversal direction
or first in one direction and then in the other, by using any known means in the art,
for instance a blade, a heated knife or a laser beam.
[0041] In a second embodiment the composite web is wound into a roll and the conversion
into the single pads is performed at a later stage at the pad manufacturing facility
or right before the packaging operations take place at the food packaging facility.
[0042] If the composite web contains more than one stripe of liquid absorbent material laminated
onto the rigid or semi-rigid web, so that longitudinal cuts are anyway required to
obtain single pads, in a third embodiment said composite web will be cut only longitudinally
at the pad manufacturing facility and each of the thus obtained "single" webs will
be wound into a roll and converted into the single pads by transversal cuts at a later
stage, for instance at the food packaging facility. Alternatively the longitudinal
cuts to convert the composite "multiple" web into the corresponding number of "single"
webs may be carried out by suitably slitting a roll of the "multiple" composite web.
[0043] A further specific object of the present invention is therefore a composite web of
a rigid or semi-rigid web of a liquid impermeable mono or multi-layer material with
longitudinally laminated thereto at least one stripe of liquid absorbent material,
wherein the size and respective positioning of the rigid or semi-rigid web and of
the stripes is such that said composite web can be converted into the final pads of
the invention, each one of them having at least one edge which only comprises the
rigid or semi-rigid support and is void of any absorbent material, by a series of
transverse and possibly longitudinal cuts, said composite web being wound into a roll.
[0044] The liquid absorbent material can be either heat- or glue-laminated onto the rigid
or semi-rigid sheet of liquid impermeable material.
[0045] When the stripe or stripes of absorbent material are glue-laminated to the support
web, preferably a layer of a suitable adhesive is coated either on the stripe of absorbing
material or onto the support web, before or at the time of lamination. When the adhesive
is coated onto the support web, it is preferably distributed at least on the surface
thereof that will be covered by the stripe(s). More preferably however a surface larger
than that covered by the stripe will be coated so that no separate additional step
will then be required to apply to the exposed portion of the surface of the support
means for binding the pad to the container, as the adhesive layer on the surface of
the support web that is not involved in the glue lamination of the stripe(s) will
represent a suitable mean for binding the pad to the container. Preferably the glue
is selected from the group of hot-melt or pressure sensitive adhesives.
[0046] When the stripe or stripes of absorbent material are heat-laminated to the support
web, the liquid impermeable sheet preferably comprises as an outer layer a heat-activated
adhesive, so that the portion of the surface of the support not covered by the liquid
absorbent material will represent a suitable mean for binding the pad to the container.
Preferably, the heat- activated adhesive is made of a material chosen from the group
of ethylene-vinyl acetate copolymers, copolymers of ethylene and alkyl esters of acrylic
or methacrylic acid, styrene/isoprene block copolymers, styrene/butadiene block copolymers
and blends thereof.
[0047] The process for obtaining the pad according to the first embodiment of the present
invention is schematically described in Figure 2. Foamed polystyrene sheet web 31
is unwound from foamed polystyrene roll 32 and fed to a glue applying station 33 that
applies a layer of suitable adhesive onto the surface of foamed polystyrene web 31.
Foamed polystyrene web 31 is then fed to lamination station 34. The stripe or stripes
of absorbing material 40 are unwound from absorbent material roll or rolls 41 and
also fed to laminating station 34 where they are laminated to foamed polystyrene web
31. The composite web 50 is then fed to a diamond-shaped punch press 35 that forms
the rounded edges 26 in the pad showed in Figure 4, needed to conform the pad to the
bottom of the tray. Composite web 50 is then fed to a cutting station 36 that cuts
the web in single pads 10. The diamond-shaped fragments that are cut out from composite
web 50 consist of foamed polystyrene material coated with a thin layer of adhesive
that can be recycled in the foamed polystyrene sheet manufacturing cycle without any
further treatment. Thus the pad manufacturing process of the present invention provides
a simple and continuous process that allows generating scrap that can be completely
recycled and eliminates the problem of producing scrap of expensive and non-recyclable
liquid absorbent material.
[0048] The process for obtaining the pad according to the third embodiment of the present
invention is schematically described in Figure 3. Foamed polystyrene sheet web 31
is unwound from foamed polystyrene roll 32 and fed to a glue applying station 33 that
applies a layer of suitable adhesive onto the surface of foamed polystyrene web 31.
Foamed polystyrene web 31 is then fed to lamination station 34. The stripe or stripes
of absorbing material 40 are unwound from absorbent material roll or rolls 41 and
also fed to laminating station 34 where they are laminated to foamed polystyrene web
31. The composite web 50 is then fed to a cutting station 135 that longitudinally
cuts the web in single webs 51, which are then individually wound into separate rolls
52. Rolls 52 are then cut transversely into single pads 10 by means of a cutting device
136.
[0049] Further advantages of the pad of the present invention can be easily appreciated
when said pad is used in conjunction with certain types of food packaging containers,
such as rigid trays. Foamed polystyrene trays, for instance, are widely used in the
packaging of meats and poultry and generally require the addition of an absorbent
pad to remove the juices exuded from the products. The use of the pad of the preferred
embodiment of the invention, described in Fig. 1, would result in a particularly appealing
and convenient final package. The rigid foamed polystyrene support of the pad would
allow the pad to blend in with the bottom of the tray and be almost invisible to the
eye of the consumer. Furthermore, the foamed polystyrene support would effectively
hide the colour imparted to the absorbent material by the absorbed juices. The pad
would also be tightly secured to the bottom of the tray thanks to the means provided
on the stripes adjacent to the absorbent mat. Therefore, a fourth object of the present
invention is a package comprising the absorbent pad of the present invention and a
container.
[0050] Suitable containers can be pouches, bags or trays made of mono- or multi- layer thermoplastic
materials. In a preferred embodiment of the present invention the container is a tray
made of plastic material. Suitable plastic materials for the container are PVC, polypropylene,
polyesters, poly(lactic acid) and foamed polystyrene. In another embodiment of the
present invention the inner surface of the container is provided with a gas barrier
composite film made of plastic material. In an even preferred embodiment of the present
invention, when the container is a tray the rigid or semi-rigid liquid impermeable
support of the absorbent pad, is made of the same material as the tray and has the
same shape and size of the bottom of the tray, so that it snugly fits the bottom of
the tray, completely covering the liquid absorbed by the pad.
[0051] The package 60 of the preferred embodiment is represented by way of example in Figures
4 and 5. A rectangular tray-shaped container 20 made of foamed polystyrene comprises
a base wall 21 completely covered by absorbent pad 10, a continuous, tapered side
wall 22 upstanding therefrom and an outwardly extending peripheral rim 23. The inner
surface of the tray is provided with a gas barrier composite film 24.
[0052] The absorbent pad 10 comprises a rigid or semi-rigid support 11 and a mat of liquid
absorbent material 12. The support 11 is made of the same foamed polystyrene sheet
as the tray and has the same size and shape as the tray base wall 21, including the
rounded edges 26 at the corners of the tray. The mat of liquid absorbent material
12 is smaller than support 11 along the transversal direction leaving two areas of
the support 11 adjacent to the side walls of the tray 23 uncovered by the absorbent
material and provided with two means 30 for binding pad 10 to the base wall 21 of
container 20.
1. A rigid or semi-rigid absorbent pad (10) suitable for the packaging of food products,
said pad comprising:
- a rigid or semi-rigid support (11) made of a liquid impermeable material having
two flat opposing surfaces, and
- a mat of liquid absorbent material (12) laminated over one of the surfaces of the
rigid or semi-rigid support,
wherein
- the mat of liquid absorbent material (12) has a surface smaller in size than that
of the rigid or semi-rigid support (11) thus leaving exposed a portion (13) of the
surface of the support onto which it is laminated; and
- means (30) are present in said exposed portion (13) of the surface of the support
(11) to bind the pad to a container,
provided said means (30) do not encircle the mat of liquid absorbing material (12)
in a continuous manner.
2. A pad (10) according to Claim 1 wherein the rigid or semi-rigid support (11) consists
of one or more layers of a thermoplastic material chosen from the group comprising
polyolefins, polyesters, polystyrenes, PVC, poly(lactic acid) and the like materials.
3. A pad (10) according to Claim 1 wherein the mat of liquid absorbent material (12)
covers from about 50 % to about 95 %, preferably from about 60 % to about 90 %, and
even more preferably from about 70 to about 85 % of the total surface of the support
(11).
4. A pad (10) according to Claim 1 wherein the liquid absorbent material (12) has a water
absorption capacity from about 500 to 7000 g/sqm, preferably from about 700 to 4500
g/sqm, and even more preferably from about 800 to 3000 g/sqm.
5. A pad (10) according to Claim 1 wherein the liquid absorbent material (12) is chosen
from the group comprising super-absorbent non-woven materials.
6. A process for the preparation of a pad (10), comprising the steps of:
- providing a rigid or semi-rigid web of a liquid impermeable mono or multi-layer
material (11) having a width in the transversal direction equal to that of the final
pad (10) or to a multiple thereof,
- longitudinally laminating at least one stripe of liquid absorbent material (12)
onto the rigid or semi-rigid web (11), said stripe of liquid absorbent material having
a width in the transversal direction inferior than the width of the final pad,
- optionally winding the obtained composite web (50) into a roll; and
- cutting the obtained composite web (50) transversely and, if more than one stripe
of absorbing material is laminated onto the support web, longitudinally, to generate
the single pads, in such a way that each pad has at least one edge which only comprises
the rigid or semi-rigid support (11) and is void of any absorbent material (12);
- applying means (30) for binding the pad to a container in the area of the support
(11) void of absorbent material.
7. The process of claim 6 wherein, if more than one stripe of absorbing material (12)
is laminated onto the support web (11), the composite web (50) is firstly cut longitudinally
into "single" webs (51), in such a way that each single web (51) of composite material
has at least one edge which only comprises the rigid or semi-rigid support (11) and
is void of any absorbent material (12), then optionally wound into individual rolls
(52) and then cut transversely to generate the single pads (10).
8. The process of claim 6 wherein the means (30) are applied as one or more spots of
glue.
9. The process of claim 6 wherein the stripe(s) of liquid absorbing material (12) are
glue-laminated to the support web (11), and the adhesive is coated onto the support
web over a surface larger than that covered by the stripe(s) so that the adhesive
layer on the surface of the support web that is not involved in the glue lamination
of the stripe(s) will provide means (30) for binding the pad (10) to a container.
10. The process of claim 9 where the glue is selected from the group of hot-melt or pressure
sensitive adhesives.
11. The process of claim 6 wherein the stripe(s) of liquid absorbent material (12) are
heat-laminated to the support web and the liquid impermeable sheet (11) comprises
an outer layer of a heat-activated adhesive, so that the portion (13) of the surface
of the support not covered by the liquid absorbent material (12) will represent a
suitable mean (30) for binding the pad (10) to a container.
12. The process according to claim 11 where the heat-activated adhesive is made of a material
chosen from the group of ethylene-vinyl acetate copolymers, copolymers of ethylene
and alkyl esters of acrylic or methacrylic acid, styrene/isoprene block copolymers,
styrene/butadiene block copolymers.
13. A process for the preparation of a roll of absorbent composite material (52) for the
production of pads (10) according to claim 1 comprising the steps of providing a rigid
or semi-rigid web of a liquid impermeable mono or multi-layer material (11) having
a width in the transversal direction equal to that of the final pad (10) or to a multiple
thereof; longitudinally laminating at least one stripe of liquid absorbent material
(12) onto the rigid or semi-rigid web (11), said stripe of liquid absorbent material
having a width in the transversal direction inferior than the width of the final pad;
if more than one stripe of absorbing material (12) is laminated onto the support web
(11), cutting the web longitudinally into "single" webs (51), in such a way that each
single web (51) of composite material has at least one edge which only comprises the
rigid or semi-rigid support (11) and is void of any absorbent material (12); winding
each single web (51) into an individual roll (52).
14. A package (60) comprising an absorbent pad (10) according to claim 1 and a container
(20).
15. The package (60) of claim 14 wherein the container (20) is a tray made of a thermoplastic
material.
16. The package (60) of claim 15 wherein the liquid impermeable support (11) of the pad
(10) according to claim 1 and the tray (20) are made of the same plastic material.
17. The package (60) of claim 15 wherein the plastic material is chosen from the group
of PVC, polypropylene, polyesters, poly(lactic acid) and foamed polystyrene.
18. The package (60) according to claim 15 wherein the absorbent pad (10) has the same
size and shape of the bottom of the tray (20).
1. Steifes oder halbsteifes Absorbenskissen (10), das zum Verpacken von Nahrungsmittelprodukten
geeignet ist, welches
- einen steifen oder halbsteifen Träger (11), der aus flüssigkeitsundurchlässigem
Material mit zwei flachen, gegenüberliegenden Oberflächen hergestellt ist, und
- eine Matte aus Flüssigkeitsabsorbensmaterial (12) umfasst, die über eine der Oberflächen
des steifen oder halbsteifen Trägers laminiert ist,
wobei
- die Matte aus Flüssigkeitsabsorbensmaterial (12) eine kleinere Oberfläche als jene
des steifen oder halbsteifen Trägers (11) hat, wodurch ein Teil (13) der Oberfläche
des Trägers, auf den sie laminiert ist, frei liegt, und
- in dem frei liegenden Teil (13) der Oberfläche des Trägers (11) Mittel (30) vorhanden
sind, um das Kissen an einen Behälter zu binden,
mit der Maßgabe, dass die Mittel (30) die Matte aus Flüssigkeitsabsorbensmaterial
(12) nicht in einer kontinuierlichen Weise umschließen.
2. Kissen (10) nach Anspruch 1, bei dem der steife oder halbsteife Träger (11) aus einer
oder mehreren Schichten eines thermoplastischen Materials besteht, das aus der Gruppe
ausgewählt ist, die Polyolefine, Polyester, Polystyrole, PVC, Poly(milchsäure) und
ähnliche Materialien umfasst.
3. Kissen (10) nach Anspruch 1, bei dem die Matte aus Flüssigkeitsabsorbensmaterial (12)
etwa 50 % bis etwa 95 %, vorzugsweise etwa 60 % bis etwa 90 % und insbesondere etwa
70 % bis etwa 85 % der Gesamtoberfläche des Trägers (11) bedeckt.
4. Kissen (10) nach Anspruch 1, bei dem das Flüssigkeitsabsorbensmaterial (12) eine Wasserabsorptionskapazität
von etwa 500 bis 7000 g/m2, vorzugsweise etwa 700 bis 4500 g/m2 und insbesondere etwa 800 bis 3000 g/m2 hat.
5. Kissen (10) nach Anspruch 1, bei dem das Flüssigkeitsabsorbensmaterial (12) ausgewählt
ist aus der Gruppe, die Superabsorbens-Vliesmaterialien umfasst.
6. Verfahren zur Herstellung eines Kissens (10), bei dem
- eine steife oder halbsteife Bahn aus flüssigkeitsundurchlässigem, ein- oder mehrschichtigem
Material (11) mit einer Breite in Querrichtung bereitgestellt wird, die derjenigen
des fertigen Kissens (10) oder einem Vielfachen davon entspricht,
- mindestens ein Streifen aus Flüssigkeitsabsorbensmaterial (12) in Längsrichtung
auf die steife oder halbsteife Bahn (11) laminiert wird, wobei der Streifen aus Flüssigkeitsabsorbensmaterial
eine Breite in der Querrichtung hat, die kleiner als die Breite des fertigen Kissens
ist,
- die erhaltene Verbundbahn (50) gegebenenfalls zu einer Rolle aufgewickelt wird,
und
- die erhaltene Verbundbahn (50) quer geschnitten wird, und, falls mehr als ein Streifen
Absorbensmaterial auf die Trägerbahn laminiert worden ist, längs geschnitten wird,
um die Einzelkissen in einer derartigen Weise zu erzeugen, dass jedes Kissen mindestens
einen Rand aufweist, der nur den steifen oder halbsteifen Träger (11) umfasst und
frei von irgendwelchem Absorbensmaterial (12) ist,
- Mittel (30) zum Binden des Kissens an einen Behälter in dem Bereich des Trägers
(11) angebracht werden, der frei von Absorbensmaterial ist.
7. Verfahren nach Anspruch 6, bei dem, wenn mehr als ein Streifen Absorbensmaterial (12)
auf die Trägerbahn (11) laminiert wird, die Verbundbahn (50) zuerst in Längsrichtung
in einer derartigen Weise zu "Einzelbahnen" geschnitten wird, dass jede Einzelbahn
(51) des Verbundmaterials mindestens einen Rand aufweist, der nur den steifen oder
halbsteifen Träger (11) umfasst und frei von irgendwelchem Absorbensmaterial (12)
ist, danach gegebenenfalls zu individuellen Rollen (52) aufgewickelt wird und danach
quer geschnitten wird, um die Einzelkissen (10) zu erzeugen.
8. Verfahren nach Anspruch 6, bei dem die Mittel (30) als einer oder mehrere Klebstoffpunkte
aufgebracht werden.
9. Verfahren nach Anspruch 6, bei dem der Streifen/die Streifen aus Flüssigkeitsabsorbensmaterial
(12) an die Trägerbahn (11) klebelaminiert werden und der Klebstoff als Beschichtung
auf die Trägerbahn über eine Oberfläche aufgebracht wird, die größer als diejenige
ist, die von dem Streifen/den Streifen bedeckt wird, so dass die Klebstoffschicht
auf der Oberfläche der Trägerbahn, die nicht an der Klebelaminierung des Streifens/der
Streifen beteiligt ist, Mittel (30) zum Binden des Kissens (10) an einen Behälter
bereitstellt.
10. Verfahren nach Anspruch 9, bei dem der Klebstoff ausgewählt ist aus der Gruppe bestehend
aus Heißschmelz- oder Haftklebstoffen.
11. Verfahren nach Anspruch 6, bei dem der Streifen/die Streifen aus Flüssigkeitsabsorbensmaterial
(12) an die Trägerbahn wärmelaminiert werden und die flüssigkeitsundurchlässige Lage
(11) eine äußere Schicht eines wärmeaktivierten Klebstoffs umfasst, so dass der Teil
(13) der Oberfläche des Trägers, der nicht von dem Flüssigkeitsabsorbensmaterial (12)
bedeckt ist, ein geeignetes Mittel (30) zum Binden des Kissens (10) an einen Behälter
darstellt.
12. Verfahren nach Anspruch 11, bei dem der wärmeaktivierte Klebstoff aus einem Material
ausgewählt aus der Gruppe von Ethylen-Vinylacetat-Copolymeren, Copolymeren von Ethylen
und Alkylestern von Acryl- oder Methacrylsäure, Styrol/Isopren-Blockcopolymeren, Styrol/Butadien-Blockcopolymeren
hergestellt ist.
13. Verfahren zur Herstellung einer Rolle Absorbensverbundmaterial (52) zur Herstellung
von Kissen (10) nach Anspruch 1, bei dem eine steife oder halbsteife Bahn eines flüssigkeitsundurchlässigen,
ein- oder mehrschichtigen Materials (11) mit einer Breite in Querrichtung gleich derjenigen
des fertigen Kissens (10) oder einem Vielfachen davon bereitgestellt wird, in Längsrichtung
mindestens ein Streifen Flüssigkeitsabsorbensmaterial (12) auf die steife oder halbsteife
Bahn (11) laminiert wird, wobei der Streifen des Flüssigkeitsabsorbensmaterials eine
Breite in Querrichtung hat, die kleiner als die Breite des fertigen Kissens ist, wobei,
wenn mehr als ein Streifen Absorbensmaterial (12) auf die Trägerbahn (11) laminiert
wird, die Bahn in Längsrichtung in einer derartigen Weise zu "Einzelbahnen" (51) geschnitten
wird, dass jede Einzelbahn (51) aus Verbundmaterial mindestens einen Rand aufweist,
der nur den steifen oder halbsteifen Träger (11) umfasst und frei von irgendwelchem
Absorbensmaterial (12) ist, und jede Einzelbahn (51) zu einer individuellen Rolle
(52) aufgewickelt wird.
14. Verpackung (60), die ein Absorbenskissen (10) nach Anspruch 1 und einen Behälter (20)
umfasst.
15. Verpackung (60) nach Anspruch 14, wobei der Behälter (20) ein aus thermoplastischem
Material hergestelltes Tablett ist.
16. Verpackung (60) nach Anspruch 15, bei der der flüssigkeitsundurchlässige Träger (11)
des Kissens (10) gemäß Anspruch 1 und das Tablett (20) aus dem gleichen Kunststoffmaterial
hergestellt sind.
17. Verpackung (60) nach Anspruch 15, bei der das Kunststoffmaterial ausgewählt ist aus
der Gruppe von PVC, Polypropylen, Polyestern, Poly(milchsäure) und geschäumtem Polystyrol.
18. Verpackung (60) nach Anspruch 15, bei dem das Absorbenskissen (10) die gleiche Größe
und Form wie der Boden des Tabletts (20) hat.
1. Tampon absorbant rigide ou semi-rigide (10) approprié pour l'emballage de produits
alimentaires, ledit tampon comprenant:
- un support rigide ou semi-rigide (11) constitué d'un matériau imperméable aux liquides
présentant deux surfaces opposées planes, et
- un matelas de matériau absorbant les liquides (12) stratifié sur une des surfaces
du support rigide ou semi-rigide,
dans lequel
- le matelas de matériau absorbant les liquides (12) a une surface inférieure en taille
à celle du support rigide ou semi-rigide (11) laissant ainsi exposée une portion (13)
de la surface du support sur laquelle il est stratifié, et
- des moyens (30) sont présents dans ladite portion exposée (13) de la surface du
support (11) pour lier le tampon à un conteneur,
à condition que lesdits moyens (30) n'encerclent pas le matelas de matériau absorbant
les liquides (12) de manière continue.
2. Tampon (10) selon la revendication 1, dans lequel le support rigide ou semi-rigide
(11) consiste en une ou plusieurs couches d'un matériau thermoplastique choisi dans
le groupe comprenant les poly(oléfines), les poly(esters), les poly(styrènes), le
PVC, le poly(acide lactique) et des matériaux similaires.
3. Tampon (10) selon la revendication 1, dans lequel le matelas de matériau absorbant
les liquides (12) couvre d'environ 50 % à environ 95 %, de préférence d'environ 60
% à environ 90 %, et de manière encore plus préférée d'environ 70 à environ 85 % de
la surface totale du support (11).
4. Tampon (10) selon la revendication 1, dans lequel le matériau absorbant les liquides
(12) a une capacité d'absorption d'eau d'environ 500 à 7 000 g/m2, de préférence d'environ 700 à 4 500 g/m2, et de manière encore plus préférée d'environ 800 à 3 000 g/m2.
5. Tampon (10) selon la revendication 1, dans lequel le matériau absorbant les liquides
(12) est choisi dans le groupe comprenant des matériaux non tissés super absorbants.
6. Procédé de préparation d'un tampon (10), comprenant les étapes consistant à:
- fournir une toile rigide ou semi-rigide d'un matériau mono ou multicouche imperméable
aux liquides (11) ayant une largeur dans la direction transversale égale à celle du
tampon final (10) ou à un multiple de celle-ci,
- stratifier longitudinalement au moins une bande de matériau absorbant les liquides
(12) sur la toile rigide ou semi-rigide (11), ladite bande de matériau absorbant les
liquides ayant une largeur dans la direction transversale inférieure à la largeur
du tampon final,
- facultativement enrouler la toile composite obtenue (50) en un rouleau, et
- découper la toile composite obtenue (50) transversalement et, si plus d'une bande
de matériau absorbant est stratifiée sur la toile de support, longitudinalement, pour
générer les tampons uniques, de telle sorte que chaque tampon a au moins un bord qui
comprend uniquement le support rigide ou semi-rigide (11) et qui est dépourvu de tout
matériau absorbant (12),
- appliquer des moyens (30) pour lier le tampon à un conteneur dans la zone du support
(11) dépourvue de matériau absorbant.
7. Procédé selon la revendication 6, dans lequel, si plus d'une bande de matériau absorbant
(12) est stratifiée sur la toile de support (11), la toile composite (50) est d'abord
découpée longitudinalement en toiles « uniques » (51), de telle sorte que chaque toile
unique (51) de matériau composite a au moins un bord qui comprend uniquement le support
rigide ou semi-rigide (11) et est dépourvu de tout matériau absorbant (12), puis est
facultativement enroulée en rouleaux individuels (52) puis découpée transversalement
pour générer les tampons uniques (10).
8. Procédé selon la revendication 6, dans lequel les moyens (30) sont appliqués sous
forme d'un ou plusieurs points de colle.
9. Procédé selon la revendication 6, dans lequel la ou les bande(s) de matériau absorbant
les liquides (12) sont stratifiées-collées à la toile de support (11), et l'adhésif
est déposé sur la toile de support sur une surface supérieure à celle couverte par
la ou les bande(s) de sorte que la couche adhésive sur la surface de la toile de support
qui n'est pas impliquée dans la stratification à la colle de la ou des bande(s) formera
les moyens (30) pour lier le tampon (10) à un conteneur.
10. Procédé selon la revendication 9, dans lequel la colle est choisie dans le groupe
des adhésifs thermocollants ou autocollants.
11. Procédé selon la revendication 6, dans lequel la ou les bande(s) de matériau absorbant
les liquides (12) sont stratifiées à chaud sur la toile de support et la feuille imperméable
aux liquides (11) comprend une couche externe d'un adhésif activé à chaud, de sorte
que la portion (13) de la surface du support non couverte par le matériau absorbant
les liquides (12) représentera un moyen (30) approprié pour lier le tampon (10) à
un conteneur.
12. Procédé selon la revendication 11, où l'adhésif activé à chaud est constitué d'un
matériau choisi dans le groupe des copolymères d'éthylène-acétate de vinyle, des copolymères
d'éthylène et des alkyl esters d'acide acrylique ou méthacrylique, des copolymères
à blocs de styrène/isoprène, des copolymères à blocs de styrène/butadiène.
13. Procédé de préparation d'un rouleau de matériau composite absorbant (52) pour la production
de tampons (10) selon la revendication 1, comprenant les étapes consistant à fournir
une toile rigide ou semi-rigide d'un matériau mono ou multicouche imperméable aux
liquides (11) ayant une largeur dans la direction transversale égale à celle du tampon
final (10) ou à un multiple de celle-ci; stratifier longitudinalement au moins une
bande de matériau absorbant les liquides (12) sur la toile rigide ou semi-rigide (11),
ladite bande de matériau absorbant les liquides ayant une largeur dans la direction
transversale inférieure à la largeur du tampon final; si plus d'une bande de matériau
absorbant (12) est stratifiée sur la toile de support (11), découper la toile longitudinalement
en toiles « uniques » (51), de telle sorte que chaque toile unique (51) de matériau
composite a au moins un bord qui comprend uniquement le support rigide ou semi-rigide
(11) et est dépourvu de tout matériau absorbant (12); enrouler chaque toile unique
(51) en un rouleau individuel (52).
14. Emballage (60) comprenant un tampon absorbant (10) selon la revendication 1 et un
conteneur (20).
15. Emballage (60) selon la revendication 14, dans lequel le conteneur (20) est un plateau
constitué d'un matériau thermoplastique.
16. Emballage (60) selon la revendication 15, dans lequel le support imperméable aux liquides
(11) du tampon (10) selon la revendication 1 et le plateau (20) sont constitués de
la même matière plastique.
17. Emballage (60) selon la revendication 15, dans lequel la matière plastique est choisie
dans le groupe du PVC, du poly(propylène), de poly(esters), du poly(acide lactique)
et du poly(styrène) en mousse.
18. Emballage (60) selon la revendication 15, dans lequel le tampon absorbant (10) a la
même taille et la même forme que le fond du plateau (20).