U.S. patent application number 11/227124 was filed with the patent office on 2006-01-12 for method and apparatus for producing labeled, plastic foam containers, and product of same.
This patent application is currently assigned to GRUPO CONVERMEX, S.A. DE C.V.. Invention is credited to Benito Alvarez.
Application Number | 20060005917 11/227124 |
Document ID | / |
Family ID | 34426033 |
Filed Date | 2006-01-12 |
United States Patent
Application |
20060005917 |
Kind Code |
A1 |
Alvarez; Benito |
January 12, 2006 |
Method and apparatus for producing labeled, plastic foam
containers, and product of same
Abstract
A method and apparatus for producing labeled, plastic foam
containers, such as a labeled EPS cup uses a heated pocket to
thermally bond a label to a plastic cup. Also described is a
labeled plastic foam container, such as a labeled EPS cup, having
high quality printing capabilities, sufficient stiffness,
acceptable insulation and barrier properties and reduced production
cost.
Inventors: |
Alvarez; Benito; (Puebla
City, MX) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
GRUPO CONVERMEX, S.A. DE
C.V.
|
Family ID: |
34426033 |
Appl. No.: |
11/227124 |
Filed: |
September 16, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/IB04/00351 |
Oct 1, 2004 |
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11227124 |
Sep 16, 2005 |
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60507944 |
Oct 3, 2003 |
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60510519 |
Oct 14, 2003 |
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Current U.S.
Class: |
156/215 ;
156/556; 156/567; 264/46.4; 428/36.5 |
Current CPC
Class: |
B29C 66/71 20130101;
B29C 65/7847 20130101; B29C 66/919 20130101; B29C 66/727 20130101;
B65C 3/14 20130101; Y10T 428/139 20150115; B29C 66/71 20130101;
B29C 66/7486 20130101; B29C 44/14 20130101; Y10T 156/1033 20150115;
B29C 65/48 20130101; Y10T 156/1768 20150115; B29C 66/742 20130101;
B65D 25/36 20130101; B29C 66/71 20130101; B29C 66/7313 20130101;
Y10T 156/1744 20150115; Y10T 428/1393 20150115; B29C 65/7841
20130101; B29C 65/26 20130101; Y10T 156/1771 20150115; B29C 33/04
20130101; B29K 2305/02 20130101; Y10T 428/1352 20150115; B29C 63/22
20130101; B29C 66/8322 20130101; B29C 66/9161 20130101; B29L
2031/744 20130101; Y10T 156/1776 20150115; B29C 65/4815 20130101;
B29C 66/91421 20130101; B29C 66/1122 20130101; B29C 66/53245
20130101; B29C 2795/002 20130101; B29C 65/18 20130101; B29C 66/63
20130101; B29K 2023/12 20130101; B29K 2023/10 20130101; B29K
2023/06 20130101; B65C 9/25 20130101; B65C 3/065 20130101; B29L
2031/7132 20130101; B29C 63/18 20130101; B29K 2105/04 20130101;
B29K 2311/12 20130101; Y10T 428/1376 20150115; B65C 9/02 20130101;
B29C 35/049 20130101; B29C 66/24221 20130101; B29C 66/71
20130101 |
Class at
Publication: |
156/215 ;
156/556; 156/567; 264/046.4; 428/036.5 |
International
Class: |
B65C 3/16 20060101
B65C003/16; B65C 9/00 20060101 B65C009/00; B29D 22/00 20060101
B29D022/00; B29C 67/00 20060101 B29C067/00 |
Claims
1. A method for labeling a plastic foam container comprising:
automatically positioning an unlabeled, preformed plastic foam
container onto a mandrel at a first station; applying a label to an
exterior surface of the plastic foam container at a second station;
directly heating a work piece that defines a cavity that
corresponds substantially in shape to the outer surface of the
plastic foam container; positioning the work piece so that the
cavity substantially surrounds the exterior surface of said plastic
foam container to which the label is applied at a third station;
directly heating the exterior surface of the plastic foam container
to which the label is applied with said cavity as the plastic foam
container is disposed within the cavity, at a temperature and a
time sufficient to bond the label to exterior surface of the
container to provide a resulting labeled, plastic foam container;
and removing the resulting labeled, plastic foam container from the
mandrel.
2. The method of claim 1, wherein automatically positioning an
unlabeled, preformed plastic foam container includes automatically
loading said unlabeled, preformed plastic foam containers with an
indexing turrent.
3. The method of claim 1, wherein the cavity is heated to a
temperature in a range of about 135.degree. C. to about 150.degree.
C.
4. The method of claim 1, wherein the cavity is heated with heating
elements that are in thermal contact with the surface of the
cavity.
5. The method of claim 1, wherein the cavity is heated by applying
steam to the cavity.
6. The method of claim 1, further comprising applying pressure to
the exterior surface to which the label is applied with the
cavity.
7. The method of claim 1, wherein the work piece comprises a metal
cylinder that is positioned to move relative to the mandrel onto
which the cup is positioned.
8. The method of claim I, wherein the mandrel is provided on a
rotating turret that moves the mandrel successively to the first
station at which the plastic foam container is placed on the
mandrel, the second station at which the label is applied to the
plastic foam container, and the third station at which the cavity
is positioned to surround exterior surface of the plastic foam
container to which the label is applied.
9. The method of claim 8, wherein the work piece comprises a metal
cylinder that is positioned at the third station to move relative
to the mandrel onto which the plastic foam container is
positioned.
10. The method of claim 1, wherein the label is affixed to said
plastic foam container with at least one of a thermal agent, a hot
melt, or a plastic coating.
11. The method of claim 10, wherein the plastic coating comprises
at least one of polyethylene or polypropylene.
12. The method of claim 1, wherein the plastic foam container,
prior to application of the label, has a density of less than 0.8
g/cm.sup.3.
13. The method of claim 12, wherein the plastic foam container,
prior to application of the label, has a density in the range of
about 0.041 to 0.076 g/cm.sup.3.
14. The method of claim 12, wherein the resulting labeled, plastic
foam container has an overall density in the range of
0.05720-0.1888 g/cm.sup.3.
15. The method of claim 1, wherein the label comprises at least one
of paper, aluminum or plastic film.
16. The method of claim 1, wherein said plastic foam container is a
cup.
17. The method of claim 16, wherein the plastic foam cup comprises
EPS.
18. A labeled, plastic foam container manufactured according to the
method of claim 1.
19. An apparatus for labeling a plastic foam container comprising:
means for automatically positioning a preformed plastic foam
container onto a mandrel at a first station; means for applying a
label to an exterior surface of the plastic foam container at a
second station; a work piece that defines a cavity, said work piece
being movable relative to the mandrel at a third station so that
the cavity substantially surrounds and heats the plastic foam
container at the exterior surface to which the label is applied,
wherein said work piece is configured to be directly heated to a
temperature sufficient to bond the label to exterior surface of the
container to provide a resulting labeled, plastic foam container;
and means for removing the resulting labeled, plastic foam
container from the mandrel.
20. The method of claim 1, wherein the means for automatically
positioning an unlabeled, preformed plastic foam container includes
an indexing turret configured to automatically load said unlabeled,
preformed plastic foam containers at the first station.
21. The apparatus of claim 19, wherein the work piece comprises a
metal cylinder that is adapted to move relative to the mandrel onto
which the container is positioned when the mandrel is at the third
station.
22. A machine for labeling plastic, foam containers comprising: a
rotatable turret having a plurality of mandrels attached thereto,
the turret being driven to rotate the mandrills to a plurality of
stations, wherein the mandrels are configured to receive a plastic
foam container; a container feeder provided at a first station to
feed an unlabeled, preformed plastic foam container onto a mandrel,
a sleeve transfer device provided at a second station being
configured to wrap and affix a label to a plastic foam container on
one of the mandrels; and a work piece defining a cavity provided at
a third station, the cavity being configured to be positioned over
the outer surface of a plastic foam container on one of the
mandrels, so as to substantially surround the exterior surface to
which the label is applied, wherein the cavity is configured to be
directly heated to a temperature sufficient to bond the label to
the plastic foam container.
23. The machine of claim 22, wherein the cavity is heated to a
temperature in a range of about 135.degree. C. to about 150.degree.
C.
24. The machine of claim 22, wherein the cavity is heated with
heating elements that are in thermal contact with the surface of
the cavity.
25. The machine of claim 22, wherein the cavity is heated by
applying steam to the cavity.
26. The machine of claim 22, wherein the cavity is configured to
apply pressure to the exterior surface to which the outer surface
of a plastic foam container on one of the mandrels.
27. The machine of claim 22, wherein the cavity is formed within a
metal cylinder that is positioned to move relative to the
turret.
28. A labeled plastic foam container comprising: an inner plastic
foam portion having a density of less than 0.8 g/cm.sup.3; an outer
sleeve that adheres to an outer surface of said inner plastic foam
portion, the outer sleeve having an outwardly facing surface to
which is applied print or graphical designs, the outer sleeve
providing stiffness to the inner portion.
29. The labeled plastic foam container, wherein the resulting
labeled, plastic foam container has an overall density in the range
of 0.05720-0.1888 g/cm.sup.3.
30. The labeled plastic foam container, wherein the inner plastic
foam portion defines a cup shape with a lip portion, bottom
portion, and sidewall.
31. The labeled plastic foam container according to claim 30,
wherein the inner plastic foam portion comprises EPS.
32. The labeled plastic foam container according to claim 28,
wherein the outer sleeve comprises one of a metal foil, a plastic
film or a paper sleeve.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of Application
PCT/IB2004/003517, filed Oct. 1, 2004, which application claims the
benefit under 35 USC 119(e) of U.S. application Ser. No.
60/507,944, filed Oct. 3, 2003, U.S. application Ser. No.
60/510,519, filed Oct. 14, 2003. The respective disclosures of each
of these related application are incorporated herein by reference
in their entireties.
FIELD OF THE INVENTION
[0002] This invention relates to a method and apparatus for
producing labeled, plastic foam containers, such as, for example, a
labeled expanded polystyrene cup. It further relates to a labeled,
plastic foam container, such as a labeled expanded polystyrene
cup.
BACKGROUND OF THE INVENTION
[0003] Plastic foam containers, such as cups and other receptacles
are widely used. Such containers can be made from different
materials, including expanded polystyrene (EPS). Plastic foam
containers, such as those made of EPS, are relatively inexpensive
and have excellent insulating properties for holding both hot and
cold fluids. Plastic foam containers, however, typically have poor
printing capabilities. That is, it is difficult to apply print or
graphical designs directly to the surface of plastic foam
containers, such as EPS containers.
[0004] In order to improve aesthetics and other properties, it is
desirable to apply a label to a plastic foam container. Traditional
labeling devices suffer from certain limitations. For example, it
is often complicated to apply labels to foam containers with
conical surfaces, such as cups. It is particularly difficult to
cover substantially the entire outer surface of such a container,
such as the entire outer wall of a cup. It is also difficult to
achieve proper and consistent bonding between the label and the
cup.
[0005] It is therefore desirable to provide a process for forming a
labeled plastic foam container in which: (1) labels are applied at
sufficiently high speed; and (2) good bonding is obtained between
the container and the label. In the latter case improving the
bonding between the foam container and the label includes avoiding
poor bonding, for example, from formation of air bubbles or loose
edges; avoiding loose labels wrapped to the labeled foam container;
and avoiding deformation on the geometries of the labeled foam
container.
SUMMARY OF THE INVENTION
[0006] According to one aspect of the invention, a method for
labeling a plastic foam container, includes: providing an unlabeled
plastic foam container, made of, for example, EPS; positioning the
plastic foam container onto a mandrel; applying a label to an
exterior surface of the plastic foam container as the plastic foam
container is positioned on the mandrel; positioning a cavity that
corresponds substantially in shape to the outer surface of the
plastic foam container relative to the mandrel onto which the
container is positioned so as to substantially surround the
exterior surface to which the label is applied; heating the plastic
foam container at the exterior surface to which the label is
applied with the cavity being at a sufficient temperature and for a
time sufficient to bond the label to exterior surface of the
container to provide a resulting labeled, plastic foam container;
and removing the resulting labeled, plastic foam container from the
mandrel. In a preferred embodiment, the plastic foam container is a
plastic foam cup.
[0007] Preferably, the cavity is heated to a temperature in a range
of about 135.degree. C. to about 150.degree. C. Heating may be
accomplished by providing heating elements within the cavity.
Alternatively, steam may be applied to the exterior of the cavity
and/or input into the cavity.
[0008] According another feature of the invention, the cavity is
used to apply pressure to the exterior surface to which the label
is applied.
[0009] According to yet another feature of the invention, the
cavity is formed within a metal cylinder that is positioned to move
relative to the mandrel onto which the foam plastic container is
positioned.
[0010] According to still another feature of the invention, the
mandrel is provided on a rotating turret that moves the mandrel
successively to: a first station at which the plastic foam
container is placed on the mandrel; a second station at which the
label is applied to the plastic foam container; and a third station
at which the cavity is positioned to surround exterior surface of
the plastic foam container to which the label is applied.
[0011] According to another feature of the invention, the label is
affixed with at least one of a thermal agent, a hot melt, and/or a
plastic coating. The plastic coating may comprise one or more of
polyethylene, polypropylene, and any other suitable polymer or
co-polymer or mixtures thereof.
[0012] According to another aspect of the invention, a machine for
labeling plastic, foam containers comprises: a rotatable turret
having a plurality of mandrels attached thereto. The turret is
driven to rotate the mandrills to a plurality of stations, wherein
the mandrels are configured to receive a plastic foam container,
preferably from a cup feeder provided at a first station. The
mandrels may be further configured to affix a label to a plastic
foam container on one of the mandrels, preferably from a sleeve
transfer device at a second station. The mandrels may be further
configured to be received within a cavity that is so configured to
be positioned over the outer surface of a plastic foam container
that is placed on one of the mandrels, so as to substantially
surround the exterior surface to which the label is applied at a
third station.
[0013] According to another aspect of the invention, the method and
apparatus according to the invention are used to manufacture
labeled, plastic foam containers, wherein the label has good
printing characteristics. Preferably, the label is formed of at
least one of paper, aluminum or plastic film, and mixtures thereof.
The person having ordinary skill in the art would understand the
types of suitable materials for use in the label for the labeled
foam containers according to the present invention.
[0014] According to a feature of the invention, a plastic foam
container made according to a method or machine of the invention,
prior to labeling, has relatively low density and stiffness, but
after application of the label, has an overall stiffness and
density that is comparable to similarly sized conventional foam
containers. Preferably, the plastic foam container, prior to
application of the label, has a density of less than 0.8
g/cm.sup.3. More preferably, the plastic foam container, prior to
application of the label, has a density in the range of about 0.041
to 0.076 g/cm.sup.3. Preferably, the resulting labeled, plastic
foam container has an overall density in the range of
0.05720-0.1888 g/cm.sup.3.
[0015] According to another aspect of the invention, a labeled
plastic foam container has an inner plastic foam portion having a
density of less than 0.8 g/cm.sup.3, and an outer sleeve that
adheres to an outer surface of said inner plastic foam portion. The
outer sleeve has an outwardly facing surface to which is applied
print or graphical designs, the outer sleeve providing stiffness to
the inner portion. The label may be applied made according to a
method or machine of the invention, prior to labeling, has
relatively low density and stiffness, but after application of the
label, has an overall stiffness and density that is comparable to
similarly sized conventional foam containers.
[0016] According to a feature of the invention, the inner plastic
foam portion defines a cup shape with a lip portion, bottom
portion, and sidewall. Preferably, the inner plastic foam portion
comprises EPS.
[0017] The stiffness obtained by the combination of plastic foam
and label materials permits the use of substantially less EPS resin
in comparison with a standard plastic foam container of comparable
(or even less) volume capacity. The particular combination of a
lower resin content, such as EPS resin, combined with a sleeve
providing improved rigidity results in a container having a
significantly lower cost than prior containers made out of paper
and/or plastic. The outer sleeve dramatically improves printability
in comparison to standard foam containers. This may result in
particular by using a pre-printed label. Further, the container
according to the invention further provides comparable or improved
stiffness, barrier properties and insulation in comparison with
comparable sized-containers.
[0018] Other features and advantages of the invention will be
apparent from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In the drawings:
[0020] FIG. 1 is a schematic view of a machine for labeling a
plastic foam container in accordance with a first embodiment of the
invention.
[0021] FIG. 2 is a top view of the labeling machine in accordance
with a first embodiment of the present invention showing the
location of the mandrels on the turret.
[0022] FIG. 3 is a cross-sectional view of a labeling machine in
accordance with a first embodiment, illustrating a device having a
heated cavity positioned above a mandrel.
[0023] FIG. 4 is a side perspective view of a labeling machine in
accordance with a first embodiment of the present invention.
[0024] FIG. 5 is a side perspective view of a labeling machine in
accordance with a first embodiment of the present invention.
[0025] FIG. 6 is a top perspective view of a sleeve transfer device
in accordance with a first embodiment of the present invention.
[0026] FIG. 7 is a perspective view of a labeled, plastic foam
container made in accordance with one embodiment of the
invention.
[0027] FIG. 8 is a cross-sectional view of a labeled plastic foam
container, wherein the foam wall of the container has reduced wall
thickness.
[0028] FIG. 9 is a cross-sectional view of a labeled plastic foam
container, wherein the foam wall of the container has reduced
density.
[0029] FIG. 10 is an illustrative cross-sectional view of a
standard foam container with optional label.
[0030] FIGS. 11A-11C are graphical, comparative representation of
the densities of plastic foam containers and labeled plastic foam
containers.
[0031] FIGS. 12A-12H are images of containers according to the
present invention having various graphical indicia printed
thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] The following describes machines for labeling plastic foam
containers, and a process for using such machines, in accordance
with various embodiments of the present invention. It should be
appreciated, however, that the following description is intended to
be merely exemplary of the various features of the invention and
should not limit the proper scope of the appended claims.
[0033] FIG. 1 is a schematic view of a machine 10 for forming a
labeled plastic foam container 15 in accordance with a first
embodiment of the invention. As illustrated, the machine 10
includes a turret 12 having a plurality of mandrels 14 attached
thereto. Each mandrel 14 has a tapered shape and is configured to
receive a plastic foam container 17, which is preferably an EPS
cup.
[0034] The turret 12 of this example is driven by a shaft 16, which
is operatively connected to an index drive 18, of a type
conventionally known in the art. The index drive 18 rotates the
turret 12 by 90 degrees so as to precisely align the mandrels 14 at
each of the stations 20, 22, 24, 26 as illustrated in FIG. 2, which
illustrates a top view of the labeling machine in accordance with a
first embodiment of the present invention showing the location of
the mandrels 14 on the turret 12. While four stations are shown, it
will be appreciated that a any number of stations may be provided
in the machine 10.
[0035] As illustrated in FIG. 1, at a first station 20 unlabeled
plastic foam containers 17 are placed onto the mandrels 14 from the
cup dispensing apparatus 19 via an actuator 28. The cup dispensing
apparatus may include a rotating turret that automatically loads
the unlabeled plastic foam containers 17 onto the mandrels 14. At a
second station 22, the label 13 is applied to the plastic foam
container 17 as discussed in more detail below. At a third station
24, the label 13 is bonded to the plastic foam container 17 to form
the labeled plastic foam container 15. The labeled plastic foam
container 15 is removed from the mandrel 14 at a fourth station
26.
[0036] Reference is now made to FIG. 3. At a third station 24,
there is provided a work piece 30, formed as a metal cylinder. The
work piece 30 attaches to a vertical shaft 31 which is driven
pneumatically, according to techniques known in the art, to raise
and lower as illustrated in FIGS. 1 and 3. In accordance with one
feature of the invention, the work piece 30 has a cavity or pocket
32 formed within it. In this embodiment, the open end of the cavity
faces downward toward the turret 12.
[0037] The cavity or pocket 32 has a tapered shape, configured to
conform to the outer dimensions of a plastic foam container
disposed on a mandrel 14. The cavity or pocket 32 is configured in
conformance with the shape of the mandrels 14. As illustrated in
FIGS. 1 and 3, a pneumatic piston drives the cavity vertically
(upward and downward in this view) toward an opposing mandrel 14
disposed beneath the cavity 32.
[0038] According to a feature of the invention, the
cylindrically-shaped work piece 30 that includes the cavity 32 is
heated so that it can be used to bond a label to a plastic foam
container disposed on a the mandrel 14. In this example, the work
piece 30 is connected to a steam inlet line 34. Steam is fed
through the steam inlet line 34 to the interior 36 of the
cylindrically-shaped piece 30, by which the inner surface 35 of the
cavity 32 may be rapidly heated. Application of steam may be
controlled automatically for example, with a controller actuated
valve (not shown) and steam condensate is removed via steam
condensate line 38. While it has been found that steam heating
provides many advantages, particularly rapid heating, other
techniques for heating the cavity are possible, such as electric or
gas heaters, or other heating elements. Such devices can be adapted
to achieve similar results but will, of course, typically involve
different energy costs and yields. It has been found that the use
of steam is particularly advantageous for use with EPS containers
due to its efficiency. Further, steam is typically used in
manufacturing EPS containers and is therefore readily
available.
[0039] Optionally, the work piece 30 may be configured to be driven
downward to apply pressure to a plastic foam container 17 and label
13 disposed on the mandrel 14. Pressure may be applied mechanically
or by air pressure. It has been found that application of pressure
promotes quicker and more homogenous bonding between the label 13
and the foam container 17. Further, it has been found that heat
transfer to bond containers to the labels 13 is improved by using
air pressure or mechanical pressure inside the pocket.
[0040] At a fourth station 26, labeled foam containers 15 are
removed from the turret 14. Removal may be accomplished by
techniques well known in the art, such as, for example,
suction.
[0041] Reference is now made to FIGS. 4, 5 and 6. The sleeve
transfer device 40 inserts the label 13 onto the unlabeled plastic
foam cup 17 that has already been placed on the mandrel 14 at the
first station 20. The mechanism illustrated in the figure is
conformed for a rotating table 44 driven from an index device 45
having, for example, four positions. The index device 45 is driven
by an electric drive 46 which may include a gear box 47. The index
device 45 may have four positions. At the 90.degree. position,
unfolded labels 13 are wrapped in a mandrel 42 by two cone shaped
revolving wings 41, 43. The sleeve is held to the mandrel 42 by a
vacuum and the seam of the label 13 is formed. The rotating table
44 is then moved to the 180.degree. position for cooling the labels
13 and then moved to the 270.degree. position where vacuum is
turned off and the label 13 is released from the mandrel 42 to the
transfer pocket 48 horizontally. The label 13 is affixed to the
transfer pocket 48 by vacuum and moved by a pneumatic linear
cylinder 51 to rotate the label 13 90.degree. so as to position the
label 13 over the mandrel 14 at the second station 22 for applying
the label 13 to the foam container 17. The vacuum in the transfer
pocket 48 is turned off to deliver the label 13 to the foam
container 17 in the second station 22.
[0042] In operation, an unlabeled plastic foam cup, preferably made
of EPS, is placed on a mandrel 14 at the first station 20. The
turret 12 indexes by 90 degrees, forwarding the unlabeled container
17 to the second station 22, at which a label 13 is applied to an
exterior surface of the plastic foam container 17 to form the
labeled foam container 15. The turret 12 indexes an additional 90
degrees, forwarding the plastic foam container with the unbonded
label 13 to the third station 24. At the third station, the heated
cavity 32 is lowered over the mandrel 14 onto which the foamed
container 17 is positioned, so as to substantially surround the
exterior surface to which the label 13 is applied. The cavity 32
heats the plastic foam container 17 at the exterior surface to
which the label 13 is applied, at a temperature and a time
sufficient to bond the label to exterior surface of the foamed
container 17 to form the labeled foam container 15. The resulting
labeled, plastic foam container 15 is indexed to the fourth station
26, at which it is removed from the turret 12 and the mandrel
14.
[0043] Preferably, the cavity 32 is heated to a temperature in a
range of about 135.degree. C. to about 150.degree. C. It has been
found that heating above 170.degree. C. is not preferred, as higher
temperatures tend deform the container shape and geometry, although
temperature ranges will vary depending on the composition of the
container, as well as the label and any bonding agent that are
used.
[0044] Preferably, the label 13 is affixed with at least one of a
thermal agent, a hot melt, and a plastic coating. The plastic
coating may comprise one or more of polyethylene, polypropylene,
and any other suitable polymer or co-polymer or mixtures
thereof.
[0045] Various labels 13 may be used with the invention. These
include, for example, polypropylene and polyethylene films, paper,
coated papers, aluminum or plastic film, and metallic laminations.
Preferably, the label has good printing characteristics to provide
improved aesthetic appearance. The person having ordinary skill in
the art would understand the types of suitable materials for use in
the label for the labeled foam containers according to the present
invention.
[0046] It will be appreciated that systems according to the
invention may be modified in many ways. For example, while the
machine 10 has been described with reference to the above figures
with the mandrels being disposed horizontally with respect to their
longitudinal axes, i.e., in a vertical orientation. It should be
understood that the machine can be configured such that the
mandrels may be disposed vertically with respect to their
longitudinal axes, i.e., in a horizontal orientation.
[0047] One advantage to the invention is its speed and accuracy.
Embodiments have been constructed by modification of conventional
machines used to manufacture paper cups. Such machines are
particularly suited for high-speed manufacturing, in which a paper
cut-out is wrapped to forms the sides of a container and a bottom
portion is formed. The container is then disposed in a cavity with
its upper portion exposed so the rim may be formed. Conventionally,
however, the cavity used for forming the rim of a paper cup, is not
heated.
[0048] As noted above, application of air or mechanical pressure
enhances heat transfer, thus increasing machine and process speed.
The optimal amount of pressure differs depending on, for example,
the size of the cup/container needed to be labeled. Further, the
amount of pressure is limited to a point where the cup/container
can be partially collapsed and deformed.
[0049] It has been found that, in comparison with conventional
labeling machines, the present invention is better suited to
applying a label to a greater surface area. This is particularly
true for containers, such as cups, having conical surfaces.
[0050] More particularly, trials conducted with the present
invention have demonstrated that the present invention provides
improved bonding in comparison with conventional labeling systems,
when applied to EPS cups. In particular, the cups made with the
invention exhibit good bonding characteristics.
[0051] According to a preferred feature, the invention ma be used
to manufacture a labeled foam cup with excellent aesthetic
appearance, while maintaining acceptable cost, stiffness, and
barrier characteristics.
[0052] FIG. 7 is a perspective view of a container according to the
invention, which is a cup 200 in this particular example. The cup
200 comprises an inner portion 204 made of a plastic foam, such as
EPS. The inner portion 204 defines the shape of the cup 200,
including a lip 210, bottom 212 and sidewall 215. Affixed to the
inner portion 214 is an outer sleeve 216, which in this particular
example comprises a paper label with stylized indicia "Cafe" 218
Although a cup is shown, it will be appreciated that other types of
containers, such as soup bowls, cartons or other containers, may
also be provided.
[0053] The paper label 216 has excellent printability in comparison
with standard foam products. While a paper label is illustrated in
this example, the sleeve according to the invention may comprise
other suitable materials known in the art, such as metal foils or
plastic films. Preferably, containers according to the invention
utilize paper and/or plastic films of basis weights that range:
17.5 g/m.sup.2 up to 200 g/m.sup.2.
[0054] The label 216 is bonded to the inner foam portion 214 using
a thermo-adhesive according to standard techniques known in the
art. Other bonding agents may be used, including thermal activated
agents, hot melts, plastic coatings (such as polyethylene,
polypropylene, and other polymers) and other agents known in the
art. It is noted that the particular bonding agent used may
increase the overall stiffness and performance of the
container.
[0055] According to a feature of the invention that the amount of
plastic resin used in the foam portion to which a label is affixed
is significantly less than standard, comparably sized and shaped
plastic foam containers. This is achieved by lowering the density
of the foam portion to which the label is affixed. Alternatively,
the foam portion to which the label is affixed may have smaller
thickness than standard, comparably sized and shaped plastic foam
containers.
[0056] FIG. 8 is a cross-sectional view of a cup according to an
embodiment of the invention. As illustrated, the plastic foam wall
portion 215 to which the label 216 is affixed has a thickness W1.
It also has a density .rho.. In this example, W1 is much thinner
than the thickness W3 of the wall of a conventional foam cup, such
as shown in FIG. 10.
[0057] FIG. 9 is a cross-sectional view of a cup according to
another embodiment of the invention. In this example, the plastic
foam wall portion 215' has a thickness W2 that is comparable to the
thickness W3 of a standard foam cup, such as shown in FIG. 10.
However the cup of FIG. 9 has a density .rho.2 that is less than
the density .rho.3 of a standard foam cup, such as shown in FIG.
10.
[0058] Although a thin walled cup and a low density foam cup are
shown as separate embodiments, it should be understood that a cup
according to the invention may combine these features.
[0059] FIG. 10 is a cross-sectional view of a standard foam cup.
The foam cup of FIG. 10 has a similar capacity and inner shape as
the cups of FIGS. 8 and 9. Affixed to the walls is an optional
label 216. The wall 214 of the standard foam cup has a thickness W2
and a density .rho.2.
[0060] Due to the smaller relative density and/or the smaller
relative thickness, of the portion that is covered by the outer
sleeve, containers according to the invention utilizes less resin
than a comparably sized and shaped standard foam container.
[0061] Experimentally, comparisons have been performed between
various containers according to the invention and comparable
conventional containers. It has been found that an effective range
of densities for the wall of the inner foam portion of a labeled,
molded foam containers according to the invention (having
capacities of from 4 ounces to 175 ounces) is less than about 0.08
g/cm.sup.3, or more preferably, about 0.0410 to 0.0759 g/cm.sup.3.
In comparison, a 10 ounce cup made by Autonational, identified
above, has a density of about 0.1200-0.1460 g/cm.sup.3, as measured
with the label removed. Accordingly, even relatively larger
containers according to the present invention have a substantially
lower foam density and thus require a substantially lower amount of
foam resin.
[0062] As shown below, thinner or less dense foam containers with
no outer sleeve have significantly reduced overall rigidity.
Thinner or less dense foam containers are also more susceptible to
permeation by materials in the container. It has been found,
however, that the use of appropriate outer sleeve compensates for
the reduction in rigidity and improves barrier properties. The
provision of a sleeve comprised of suitable material, such as
paper, provides for improved printability.
[0063] Experiments have been performed with various containers that
include a molded foam portion, over which a label or sleeve is
applied. As noted above, it has been found that containers with
acceptable properties have an inner foam portion (i.e., the without
the label or sleeve) having densities in the range of 0.0410-0.0579
g/cm.sup.3. By provision of the label sleeve, the finished
containers overall have densities of 0.0572-0.1888 g/cm.sup.3,
which are comparable to standard foam cups that are more expensive
due to their use of more resin. These measurements were made on a
range of containers with varying capacity using a standard density
measurement kit YDK 01LP sold by Sartorious AG. The results are
depicted in FIGS. 11A-11C.
[0064] As noted above, different types of labels may be applied in
connection with containers according to the invention. By way of
illustration, FIGS. 12A-12H illustrate cups having molded foam
inner portions and various types of labels. FIG. 12A illustrates a
plastic foam cup with 300 g/m.sup.2 paper or board label. FIG. 12B
illustrates a plastic foam cup with a polypropylene label. FIG. 12C
illustrates a plastic foam soup container with couche (type of
paper) and polyethylene 1 sided coated paper label. FIG. 12D
illustrates a plastic foam cup with paper bonded with a first
thermal agent. FIG. 12E illustrates a plastic foam cup with a paper
label, varnish and a thermal agent. FIG. 12F illustrates a plastic
foam cup with a polypropylene film label and adhesive. FIGS. 12G
and 12H illustrate other samples according to the present
invention.
[0065] From the foregoing description, it should be apparent to
those skilled in the art that the present invention provide labeled
containers/cups having the following advantages: cost efficiency;
high quality printing capabilities; sufficient stiffness;
insulation and barrier properties; minimum amount of raw materials;
and efficient stacking. In particular the present invention
provides substantial cost savings through the use of lower amounts
of resin in comparison with standard foam containers that provide
comparable performance.
[0066] Although the invention has been described in reference to
specific embodiments and examples, it will be appreciated by those
skilled in the art that the present invention can be embodied in
other forms without departing from the spirit and scope of the
invention. The presently disclosed embodiments should therefore be
considered in all respects illustrative and not restrictive.
* * * * *