U.S. patent application number 09/461313 was filed with the patent office on 2002-07-18 for lids for closing off containers.
Invention is credited to JUD, WILFRIED.
Application Number | 20020094415 09/461313 |
Document ID | / |
Family ID | 8236488 |
Filed Date | 2002-07-18 |
United States Patent
Application |
20020094415 |
Kind Code |
A1 |
JUD, WILFRIED |
July 18, 2002 |
LIDS FOR CLOSING OFF CONTAINERS
Abstract
Lids, for example lids for machine-lidding of e.g. beakers,
dishes, menu dishes, goblets, small packages etc., containing a
substrate material featuring, with respect to a container on which
the lids are used, a smooth outward facing surface bearing
printing. On the inward facing side of the lid is a sealing layer
deposited by extrusion laminate coating. The sealing layer exhibits
on the free surface embossing with a depth of roughness of up to 50
.mu.m. The embossing is transferred to the sealing layer in the
form of a roughness pattern on the cooling roll on depositing the
laminate coating of the substrate material and extruded sealing
layer. The free side of the substrate material is smooth and
exhibits no embossing. Printing on the free surface is therefore of
higher quality. The extruded sealing layer on the substrate
material exhibits embossing on the free side. If the lids are drawn
from a stack of lids, for example in a filling machine, the
embossing allows them to be separated individually. The lids are
suitable for closing off containers using a sealing seam in which
the lids contain a substrate material featuring, with respect to a
container on which the lids are used, outward facing printing and
an inward facing sealing layer.
Inventors: |
JUD, WILFRIED; (SINGEN,
DE) |
Correspondence
Address: |
FISHER CHRISTEN & SABOL
SUITE 1401
1725 K STREET NW
WASHINGTON
DC
20006
|
Family ID: |
8236488 |
Appl. No.: |
09/461313 |
Filed: |
December 15, 1999 |
Current U.S.
Class: |
428/141 |
Current CPC
Class: |
Y10T 428/24413 20150115;
B32B 27/302 20130101; B32B 2323/10 20130101; Y10T 428/28 20150115;
Y10T 428/24802 20150115; B65D 77/2024 20130101; B32B 15/08
20130101; B32B 2367/00 20130101; B32B 27/36 20130101; B32B 2323/04
20130101; Y10T 428/24612 20150115; Y10T 428/2495 20150115; Y10T
428/24405 20150115; Y10T 428/24479 20150115; B32B 23/08 20130101;
B32B 27/32 20130101; Y10T 428/24843 20150115; Y10T 428/2843
20150115; B32B 27/00 20130101; B32B 2435/02 20130101; Y10T
428/24364 20150115; B32B 27/08 20130101; Y10T 428/24355 20150115;
B32B 2325/00 20130101; B32B 2377/00 20130101; Y10T 428/2817
20150115; B32B 27/34 20130101 |
Class at
Publication: |
428/141 |
International
Class: |
B32B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 1998 |
EP |
98811233.0 |
Claims
1. Lids for closing off containers using a sealing seam in which
the lids contain a substrate material featuring, with respect to a
container on which the lids are used, outward facing printing and
an inward facing sealing layer, characterised in that, the sealing
layer on the free surface exhibits embossing with a depth of
roughness of up to -50 .mu.m and the free surface of the substrate
material showing the printing is smooth and is not embossed.
2. Lids according to claim 1, characterised in that the depth of
roughness is 3 to 30 .mu.m, usefully 3 to 20 .mu.m, advantageously
5 to 10 .mu.m.
3. Lids according to claim 1, characterised in that the sealing
layer is an extrusion layer.
4. Lids according to claim 1, characterised in that the sealing
layer is a co-extrusion layer.
5. Lids according to claim 1, characterised in that the sealing
layer is a co-extrusion layer contains a bonding agent and/or a
primer and a sealable thermoplastic.
6. Lids according to claim 5, characterised in that the sealing
layer contains sealable thermoplastics from the polyolefin series,
preferably polyethylenes or polypropylenes, copolymers or
terpolymers of ethylene or polyester or polystyroles or polyamides
or their copolymers or terpolymers.
7. Lids according to claim 1, characterised in that the substrate
material contains non-embossed thermoplastics or a non-embossed
cellophane or a non-embossed cellulose-containing material or a
non-embossed metal foil or a combination of these materials.
8. Lids according to claim 7, characterised in that the substrate
material containing a combination of at least one thermoplastic
and/or a cellophane and/or a cellulose-containing material and/or a
metal foil in the form of a multi-layer non-embossed composite
material.
9. Lids according to claim 8, characterised in that the substrate
material contains a barrier layer against gases, vapours and
moisture in the form of a ceramic layer or a metallised layer or a
plastic film or a metal foil.
10. Lids according to claim 8, characterised in that the sealing
layer exhibits a weight per unit area of 30 g/m.sup.2 and less,
usefully from 2 to 20 g/m.sup.2, advantageously from 2 to 15
g/m.sup.2, in particular from 5 to 10 g/m.sup.2.
11. Lids according to claim 10, characterised in that the sealing
layer is a co-extrudate containing a bonding agent in the form of
an extrusion layer having a weight per unit area of 2 to 10
g/m.sup.2, usefully from 2 to 8 g/m.sup.2, and an extrusion layer
of thermoplastic having a weight per unit area of 3 to 25
g/m.sup.2, in particular from 5 to 10 g/m.sup.2.
12. Process for manufacturing lids for closing off containers using
a sealing seam, where the lids contain a substrate material
featuring, with respect to a container on which the lids are used,
an outward facing printing and an inward facing sealing layer,
characterised in that, the substrate material is coated via an
extrusion coating or co-extrusion coating with an extrusion layer
or co-extrusion layer forming the sealing layer, and the coated
substrate material is passed between a pressure roll and a cooling
roll while being put under pressure, whereby the substrate material
faces the pressure roll and the extrusion layer or co-extrusion
layer faces the cooling roll, and the configuration of the surface
of the cooling roll transfers to the extrusion layer or
co-extrusion layer as a reverse image forming an embossed sealing
layer.
13. Process for manufacturing lids according to claim 12,
characterised in that the cooling layer exhibits as surface
configuration a roughness pattern having a depth of roughness of up
to 50 .mu.m, usefully from 3 to 30 .parallel.m, advantageously from
3 to 20 .mu.m, in particular 5 to 10 .mu.m.
Description
[0001] The present invention relates to lids for closing off
containers using a sealing seam in which the lids contain a
substrate material featuring, with respect to a container on which
the lids are used, outward facing printing and an inward facing
sealing layer.
[0002] It is known to provide containers such as deep drawn or
stretch drawn containers with a ring-shaped shoulder at their
opening and to lid such containers, in particular after filling,
such that the lid lies over the whole of the shoulder and e.g. by
sealing or adhesive bonding, to attach the lid permanently and in
an air-tight manner to the shoulder.
[0003] The lids are e.g. stamped out of an endless strip of lid
material and stacked. The stacks of lids are fed to a packaging
machine and the individual or unstacked lids continuously sealed on
to the already filled containers. The lids--already featuring a
sealing layer--are sealed onto the shoulder region of the container
at the edge of the container using a sealing tool. The separation
or unstacking of the lids from the stacks is not always reliably
performed by the packaging machine as the stacked lids may stick to
each other. It is possible to prevent the lids from sticking
together, for example by embossing the lid material. Embossed
patterns on the lid material, however, have a negative effect on
the printed image on the outside of the lid.
[0004] The lid material can be of various different materials
depending on the requirements in question. Typical examples of lid
material are metal foils which may be coated with plastic on one or
both sides. Other lid materials contain or comprise of plastics in
the form of mono-films or multilayer laminates. Further lid
materials can be of cellulose-containing materials such as
cellophane or paper. Also Laminates of metal foil and plastic films
are employed. In order to seal the lid material to the edge of the
container, the lid material is provided over the whole of its
surface with a sealing layer such as an organic coating or sealing
film, whereby the sealing layer is deposited at least on the side
of the finished packaging facing the inside i.e. facing the
interior of the container.
[0005] The lid material also serves as a substrate for information
and advertising. For that reason the lid material is generally
provided with printing on its outside. The printing may be on the
uppermost layer facing outwards on the finished container i.e. so
called first form printing. The printing may also be covered over
by a protective lacquer or a protective film, or the uppermost
layer may be of transparent material and bear the printing as a
reverse image in the form of counter-printing. The printed images
may be single or multi-coloured and may be deposited in a printing
machine.
[0006] Application of an embossed image is a disadvantage with
known lid materials. The embossing is necessary in order that the
lids manufactured from the lid material in stacks can be fed to the
packaging machine, and that the lids can even be separated piece
for piece from the stack and sealed onto the container. As the lid
material has to be embossed, the finished lid is at a disadvantage
to reproduce the desired image.
[0007] The object of the present invention is to overcome this
disadvantage and to propose a lid that can be separated into
individual lids from a stack of lids, yet reproduces with high
quality the image on its surface.
[0008] That objective is achieved by way of the invention in that
the sealing layer on the free surface exhibits embossing with a
depth of roughness of up to 50 .mu.m and the free surface of the
substrate material showing the printing is smooth and is not
embossed.
[0009] The depth of roughness is e.g. from 3 to 30 .mu.m, usefully
3 to 20 .mu.m and advantageously 5 to 10 .mu.m. The depth of
roughness is in particular not greater than the thickness of the
sealing layer.
[0010] The sealing layer may be an extrusion layer or a
co-extrusion layer.
[0011] The sealing layer may contain a co-extrusion layer of a
bonding agent and/or a primer and a seal-able thermoplastic. The
bonding agent and/or primer lie on the substrate material and the
sealable thermoplastic on the bonding agent and/or primer.
[0012] The sealing layer exhibits e.g. a weight per unit area of 30
g/m.sup.2 and less, usefully from 2 g/m.sup.2 to 20 g/m.sup.2,
advantageously from 2 g/m.sup.2 to 15 g/m.sup.2, in particular from
5 g/m.sup.2 to 10 g/m.sup.2.
[0013] The sealing layer may be e.g. a co-extrudate with a bonding
agent as extrusion layer having a weight per unit area of 2 to 10
g/m.sup.2, usefully from 2 g/m.sup.2 to 8 g/m.sup.2, and an
extrusion layer of a thermoplastic having a weight per unit area of
3 to 25 g/m.sup.2, in particular from 5 g/m.sup.2 to 10
g/m.sup.2.
[0014] The substrate material may be a monofilm of plastic or a
multilayer composite made up of two or more plastic layers or a
metal foil or a multilayer composite of at least one metal foil and
at least one plastic film. The substrate material may also be
comprised of a cellulose-containing material or contain a
cellulose-containing material. The cellulose-containing material
may be coated on one or both sides with a plastic layer or be
metallised or may exhibit on one side a plastic layer and a
metallised layer on the other side. The plastics of the substrate
material may be e.g. polyolefins such as polyethylenes or
polypropylenes, polyamides, polyethylene-terephthalates or
polyvinylchlorides. Steel or aluminium e.g. may be used as metal
foils. Cellulose-containing materials that may be used are e.g.
papers or semi-cardboard. Further substrate materials are e.g.
cellophane. The substrate material may have a thickness e.g. of 12
to 500 .mu.m, whereby the substrate materials in the form of
plastic films or metal foils or metal foils and plastic films are
preferably 12 to 150 .mu.m thick, while lid materials containing
cellulose-containing materials are e.g. 40 to 500 .mu.m thick. The
substrate materials are in particular flexible to such an extent
that they can be coiled into rolls.
[0015] The substrate material may also exhibit a barrier layer
against gases, vapours and moisture. Barrier layers may be--in
addition to the above mentioned metal foils--be e.g. of plastics
such as polyvinyliden-chloride or ethyl-vinyl-alcohol, or may be a
layer of ceramic material such as the oxides or nitrides of silicon
or aluminium, deposited in a vacuum deposition process onto a
substrate film as a thin layer e.g. in the thickness range of 10 to
500 nanometers. Examples of further barrier layers are metal layers
e.g. of aluminium deposited on the substrate by sputtering.
[0016] Printing may be provided on the side of the lid which on the
finished container is the outward facing side. Such printing may be
advertising, competition or information in word form and/or
imageform. The printing of the substrate material may be performed
using all known printing methods such as e.g. typographic, offset,
flexo, screen, heliographic and copper-plate printing. The choice
as to which printing method is to be used depends on the quality of
printing desired, on the prevailing technical aspects and the size
of series to be printed. Preferred is flexo-printing (also known as
aniline or rubber printing) and intaglio printing such as
copper-plate, or helio printing. The printing on the outside of the
substrate may be protected additionally e.g. by coating over with a
protective lacquer or, using a laminating agent or an adhesive, a
transparent film--e.g. of polyethylene-terephthal- ate, polyamide,
polyolefins such as polyethylene or polypropylene or a cellophane
layer which, however, in general in order to protect the printed
image is printed on by counter-printing--may be laminated onto the
substrate material. The printing may take place on the substrate
material or after depositing the sealing layer.
[0017] The non-printed material--as with the printed substrate
material--is in particular smooth and non-embossed or exhibits a
smooth surface without embossing. As a result the printing quality
is unimpaired.
[0018] The sealing layer may contain or comprise a thermoplastic,
for example from the series of polyolefins, preferably
polyethylenes or polypropylenes or copolymers or terpolymers of
ethylene e.g. copolymers or terpolymers of ethylene and acrylic
acid (EAA, ethyl acrylic acid), of ethylene and acrylic esters such
as methacrylate (EMA), ethyl acrylate (EAA) or butylacrylate
(EnBA), of ethylene and vinylacetates (EVA), of ethylene and
methacrylic acid (EMMA), of ethylene and ethylacrylate and acrylic
acid (EAEAA) or ionomer resins, alone or in mixture form. The
sealing layer may also contain one of the aforementioned
thermoplastics and bonding agent or primer, for example from the
polyester or vinylpolymer series. The sealing layers may contain or
be made of e.g. polyesters or polyamides or their copolymers or
terpolymers.
[0019] The present invention relates also to a process for
manufacturing lids for closing off containers by means of a sealing
seam, where the lid with reference to a container on which the lid
is employed, contains a substrate material with outward facing
printing and an inward facing sealing layer.
[0020] The process may be performed in such a manner that the
substrate material is coated, via extrusion coating or co-extrusion
coating, with an extrusion layer (extrusion film) or co-extrusion
layer (co-extrusion film) forming the sealing layer, and the coated
substrate material is passed between a pressure roll and a cooling
roll while being put under pressure, whereby the substrate material
faces the pressure roll and the extrusion layer or co-extrusion
layer faces the cooling roll, and the configuration of the surface
of the cooling roll transfers to the extrusion layer or
co-extrusion layer i.e. the sealing layer as a reverse image. For
example the substrate material is uncoiled from a roll as an
endless strip and passed over a pressure roll. The film or films of
the sealing layer are produced in one or more extruder nozzles in
the region of the pressure roll. In order to improve mutual
adhesion, the substrate material and/or the extrusion layer or
layers may be subjected to flame, plasma, corona or ozone
treatment. Under the action of gravity the extruded film or films
make contact with the substrate material running continuously over
the pressure roll. The contact surface of the pressure roll is
essentially smooth i.e. in particular not embossed and without any
roughness structure. The cooling roll is provided in the device as
counter roll to the pressure roll. The surface of the cooling roll
is embossed. The substrate material coated with the extruded film
or films passes between the pressure roll and the embossed cooling
roll. The surface of the pressure roll is smooth or without
embossing or the like and supports the substrate material, the free
surface of which also remains smooth while the cooling roll
transfers its image onto the solidifying extrusion film i.e. the
sealing layer. The result is a lid material one side of which, the
substrate material and printed side, is smooth and non-embossed
while the other side viz., the sealing layer side, exhibits a
roughness pattern or embossing. In other words the lid material or
the lid according to the invention therefrom exhibits one on top of
the other as the case may be, a protective lacquer or a protective
film, printing and/or counter-printing, the actual substrate
material and finally the sealing layer comprising a layer of
thermoplastic or a layer of bonding agent and/or primer and a layer
of thermoplastic, where the free surface of the layer of
thermoplastic exhibits the roughness pattern Used as a lid, the
sealing layer in particular faces the interior of the container and
the printing faces out. By employing stamping or cutting methods,
the individual lids can be made from the lid material which can be
coiled into roll form. The lids may then be stacked for e.g. use in
a filling machine.
[0021] The cooling roll preferably exhibits as surface
configuration a surface roughness pattern having a roughness depth
of up to 50 .mu.m, usefully from 3 to 30 .mu.m, advantageously from
3 to 20 .mu.m and in particular from 5 to 10 .mu.m.
[0022] The roughness pattern on the cooling roll may e.g. be
created by grinding, spark erosion, embossing, blasting with hard
materials etc. The roughness pattern should to advantage not exceed
a depth of roughness which is greater than the thickness of the
sealing layer. This means that the roughness pattern should not
penetrate the sealing layer and the embossing should also not be
transferred to the substrate material. The roughness pattern on the
cooling roll may take any form and may be a random pattern of
recesses in the surface, it may be a worm-shaped embossing,
damask-like embossing, line-shaped, stroke or dot-like pattern
etc.
[0023] The lids according to the invention of a substrate material
with--referring to containers on which the lids are used--outward
facing printing and inward facing sealing layer, find application
in the closure of containers that have a shoulder region, the lids
being attached via the sealing layer to the container in the
shoulder region. Such containers are e.g. deep drawn or stretch
drawn or cast, such as injection moulded, containers, or otherwise
shaped containers the opening in which feature a fiat ring-shaped
shoulder. The containers are lidded, in particular after filling,
and viz., such that the lid lies over the whole of the shoulder and
is attached to the shoulder in an air-tight manner e.g. by sealing
or adhesive bonding. Such beakers, dishes, menu-dishes e.g. such
with a plurality of compartments, goblets, small forms of packaging
etc. may be employed for packaging foodstuffs of all kinds such as
e.g. milk products, in particular yoghurt, cream for whipping, sour
milk, sour cream, coffee cream, ready made meals, of salads or
semi-conserved or fully conserved foodstuffs, precooked or
otherwise prepared meals, drinks such as fruit juices and vegetable
juices, drinking water etc.
[0024] The lids in question may be sealed to the rim of the
container by means of the sealing layer. The strength of the seal
can be adjusted by appropriate choice of sealing tool, the sealing
pressure and the sealing temperature. Aids to tearing may be
provided e.g. in the form of weaker sealed regions at the seam, or
by means of zigzag shaped edges to the sealing seams. Instead of
sealing via the sealing layer, the bonding may be effected using an
adhesive such as a contact adhesive or an adhesive that bonds under
the action of heat and/or pressure.
[0025] The lid material presented here has the advantage that e.g.
in order to create the sealing layer in the form of an extrusion
layer or co-extruded layer, it is not necessary to employ solvents
that have to be vaporised and recovered or destroyed. The embossing
at the sealing seam prevents the lids from sticking together on
being separated from the stack. As a result, the stacked lids
according to the invention having one smooth side and one embossed
side may be used reliably in packaging machines.
[0026] The finished lids may also feature a tear-off or gripping
flap and/or weakness, e.g. in the form of perforations or tearing
notches which make it easier to open the container on removing the
lid.
* * * * *