U.S. patent application number 11/262867 was filed with the patent office on 2007-05-03 for multiple portion packaging tray and method of making same.
Invention is credited to Christopher John Colavito, Patrick Lee O'Brien, Roy Lester Smith, Michael W. Worstell.
Application Number | 20070095719 11/262867 |
Document ID | / |
Family ID | 37994856 |
Filed Date | 2007-05-03 |
United States Patent
Application |
20070095719 |
Kind Code |
A1 |
Colavito; Christopher John ;
et al. |
May 3, 2007 |
Multiple portion packaging tray and method of making same
Abstract
A multiple portion packaging tray comprising a plurality of
pliable polymer containers configured in an array, each comprising
a receptacle and an integral peripheral flange extending from the
receptacle, the flanges integrally connecting adjacent containers
to one another along perforation lines comprising a series of
alternating openings and land areas wherein the land areas are
sized so that the containers are separated by tearing apart the
flanges without propagating cracks across the flanges. The method
of making a multiple portion packaging tray in a former comprising
a form station and a separate trim station comprising the steps of
thermoforming the multiple portion packaging tray and cutting the
perimeter and perforation lines of the multiple portion packaging
tray to create a series of alternating openings and land areas.
Inventors: |
Colavito; Christopher John;
(Newport News, VA) ; Smith; Roy Lester;
(Williamsburg, VA) ; O'Brien; Patrick Lee;
(Yorktown, VA) ; Worstell; Michael W.;
(Williamsburg, VA) |
Correspondence
Address: |
SUTHERLAND ASBILL & BRENNAN LLP
999 PEACHTREE STREET, N.E.
ATLANTA
GA
30309
US
|
Family ID: |
37994856 |
Appl. No.: |
11/262867 |
Filed: |
October 31, 2005 |
Current U.S.
Class: |
206/561 |
Current CPC
Class: |
B65D 1/30 20130101; B31D
5/0021 20130101 |
Class at
Publication: |
206/561 |
International
Class: |
B65D 1/34 20060101
B65D001/34 |
Claims
1. A multiple portion packaging tray comprising a plurality of
pliable polymer containers configured in an array and each
comprising a receptacle and an integral peripheral flange extending
from the receptacle, the flanges integrally connecting adjacent
ones of the containers to one another along perforation lines in
the flanges having a series of alternating openings and land areas,
wherein the land areas are sized so that the containers are
separable by tearing apart the flanges without propagating cracks
across the flanges.
2. The multiple portion packaging tray as in claim 1 wherein the
pliable polymer containers comprise a polyolefin.
3. The multiple portion packaging tray as in claim 2 wherein the
polyolefin is polypropylene.
4. The multiple portion packaging tray as in claim 2 wherein the
polyolefin is high density polyethylene or low density
polyethylene.
5. The multiple portion packaging tray as in claim 2 wherein the
pliable polymer containers comprise a coextruded sheet comprising
the polyolefin.
6. The multiple portion packaging tray as in claim 1 wherein each
perforation line has a longitudinal direction and the length of
each land area in the longitudinal direction of the respective
perforation line ranges from about 15 mils to about 32 mils.
7. The multiple portion packaging tray as in claim 1 wherein each
perforation line has a longitudinal direction and the length of
each land area in the longitudinal direction of the respective
perforation line ranges from about 18 mils to about 22 mils.
8. The multiple portion packaging tray as in claim 1 wherein each
perforation line has a longitudinal direction and the length of
each land area in the longitudinal direction of the respective
perforation lines is about 20 mils.
9. The multiple portion packaging tray as in claim 1 wherein the
land areas have a thickness from about 3 mils to about 40 mils.
10. The multiple portion packaging tray as in claim 1 wherein the
land areas have a thickness from about 5 mils to about 30 mils.
11. The multiple portion packaging tray as in claim 1 wherein the
flanges have channels and the perforation lines are formed in the
channels so that the thickness of the land areas is less than the
thickness of the flanges outside of the channels.
12. The multiple portion packaging tray as in claim 1 wherein the
containers are made by thermoforming a pliable polymer sheet.
13. The method of making a multiple portion packaging tray in a
former comprising a form station and separate trim station
comprising the steps of: thermoforming a pliable polymer sheet in a
form station to create the multiple portion packaging tray
comprising a plurality of pliable polymer containers configured in
an array and each comprising a receptacle and an integral
peripheral flange extending from the receptacle, the flanges
integrally connecting adjacent ones of the containers to one
another; and cutting the flanges in the trim station to form
perforation lines having a series of alternating openings and land
areas.
14. The method as in claim 13 wherein the step of cutting comprises
cutting the flanges with steel rule knives to trim the containers
and cutting the flanges along the perforation lines with notched
steel rule knives to form the open areas.
15. The method as in claim 14 wherein the notches of the notched
steel rule knives have a length that ranges from about 15 mils to
about 32 mils.
16. The method as in claim 14 wherein the notches of the notched
steel rule knives have a length that ranges from about 18 mils to
about 22 mils.
17. The method as in claim 14 wherein the notches of the notched
steel rule knives have a length of about 20 mils.
18. The method as in claim 13 wherein the pliable polymer
containers comprise a polyolefin.
19. The method as in claim 19 wherein the polyolefin is
polypropylene.
20. The method as in claim 19 wherein the polyolefin is high
density polyethylene or low density polyethylene.
21. The method as in claim 19 wherein the pliable polymer
containers comprise a coextruded sheet comprising the polyolefin.
Description
FIELD OF INVENTION
[0001] This invention relates to plastic containers for use in
packaging. In particular, this invention relates to packaging
comprising an array of separably connected plastic containers that
are easily separated and methods of making such containers.
BACKGROUND OF INVENTION
[0002] Use of single serve plastic containers is well known in the
food product industry. These single serve containers are sometimes
manufactured and sold in a multiple portion packaging tray
comprising an array of separable containers. The containers are
generally connected to one another along their flanges and may be
broken apart by breaking the connection at the flanges. These
containers work well when made of a relatively brittle plastic. Use
of less brittle or more pliable polymers makes the containers more
difficult to break apart. For some foods, brittle plastics, such as
polystyrene, cannot provide the necessary protection and a high
moisture barrier polymer is needed, such as polypropylene or
polyethylene. Polypropylene and polyethylene are also generally
lower cost materials than polystyrene. Traditionally, single serve
packages made from polyolefins include secondary packaging, such as
a cardboard sleeve, to form a multiple portion package. Connecting
individual containers to form a multiple portion packaging without
the use of secondary packaging, however, would deliver a
substantial cost benefit. Accordingly, there is a need for an array
of separably connected plastic containers made from less brittle
and more pliable polymers.
[0003] Containers in the form of an array of separably connected
plastic containers are typically formed from thermoforming
processes well known to those of skill in the art. Examples of such
thermoforming methods include solid phase pressure forming, melt
phase forming, plug assist, vacuum forming, and drape forming.
After thermoforming, the containers are transferred to a separate
trim station, outside of the thermoforming station, to trim the
containers.
SUMMARY OF INVENTION
[0004] This invention addresses the above-described need by
providing a multiple portion packaging tray comprising a plurality
of pliable polymer containers configured in an array. Each pliable
polymer container comprises a receptacle and an integral peripheral
flange extending from the receptacle, the flanges integrally
connecting adjacent containers.
[0005] More particularly, this invention comprises perforation
lines in the flanges as a means to easily separate the containers.
The perforation lines comprise a series of alternating openings and
land areas wherein the land areas are sized so that the containers
are easily separated by tearing apart the flanges without
propagating cracks across the flanges or compromising the
containers' integrity and at the same time are robust enough to
survive normal handling in a distribution process with out
separating incidentally.
[0006] In addition, this invention encompasses a method for making
a multiple portion packaging tray comprising a plurality of pliable
polymer containers configured in an array. This method is performed
in a former comprising a form station and a separate trim station
and comprises the steps of thermoforming a pliable polymer sheet in
the form station to create the multiple portion packaging tray and
cutting the flanges in the trim station to form perforation lines
having a series of alternating openings and land areas.
[0007] Other objects, features, and advantages of this invention
will be apparent from the following detailed description, drawings,
and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a plan view of an array of separably connected
plastic containers in accordance with an embodiment of this
invention.
[0009] FIG. 2a is a partial elevation view of the embodiment in
FIG. 1 illustrating a perforation line.
[0010] FIG. 2b is a partial plan view of the embodiment in FIG. 1
illustrating a perforation line along its longitudinal length.
[0011] FIG. 3 is a schematic representation of a system of making
an array of separably connected plastic containers in accordance
with an embodiment of this invention.
[0012] FIG. 4 is an exploded schematic representation of a trim
station used in the embodiment illustrated in FIG. 3.
[0013] FIGS. 5a and 5b are elevation views of notched steel rule
knives used in the embodiment illustrated in FIG. 3.
DETAILED DESCRIPTION
[0014] As summarized above, this invention encompasses a multiple
portion packaging tray comprising a plurality of pliable polymer
containers configured in an array. Such containers are frequently
used to package individual servings of food products, although
other uses are well known in the art. The containers are easily
separable from the multiple portion packaging tray through the
exertion of tensile force by hand. Embodiments of this invention
are described in detail below and illustrated in FIGS. 1-5.
[0015] A multiple portion packaging tray 10 made in accordance with
an embodiment of this invention is illustrated in FIG. 1. The
multiple portion packaging tray 10 comprises a plurality of pliable
polymer containers 12 configured in an array. The individual
containers 12 comprise receptacles such as cups 14 surrounded by
peripheral flanges 16. The flanges 16 integrally connect adjacent
containers 12 to one another. The flanges 16 comprise perforation
lines 18 wherein the perforation lines provide a means to easily
separate the individual containers 12 from the multiple portion
packaging tray 10. The perforation lines 18 may be formed within
channels 19 formed in the flanges 16, as shown in FIGS. 1, 2a and
2b, or directly in non-channeled flanges. The channels 19 can be
formed by any suitable means including but not limited to coining,
and the like. The perforation lines 18 comprise a series of
alternating openings 20 and land areas 22. The land areas 22 are
sized so that the individual containers 12 are easily separated by
tearing apart the flanges 16 at the tear lines 18 using tensile
forces without propagating cracks across the flanges 16. Desirably,
the land areas 22 can be easily pulled apart by hand yet are strong
enough to survive normal handling and shipping. The perforation
lines 18 extend along the flanges 16 in a longitudinal direction D
as illustrated in FIG. 2b. The length L of the land areas 22 in the
longitudinal direction D of the perforation lines 18 preferably
ranges from about 15 mils to about 32 mils, more preferably from
about 18 mils to about 22 mils. The length L of the land areas 22
in the longitudinal direction D of the perforation lines 18 is most
preferably about 20 mils.
[0016] The multiple portion packaging tray 10 preferably comprises
a pliable polymer material which is desirable in some packaging
applications. For example, polyolefins are suitable pliable polymer
materials for forming the packaging tray 10. Preferred polyolefins
include polypropylene, high density polyethylene, and low density
polyethylene. The most preferable polyolefin is polypropylene. The
pliable polymers also may be coextruded with other materials. For
example, polypropylene may be coextruded with ethylene vinyl
alcohol by using ethylene vinyl acetate based tie layers for
adhesion to the polypropylene. Other pliable polymer materials are
also suitable.
[0017] The thickness T of the pliable polymer can vary and is
preferably at least 3 mils and desirably ranges from 3 mils to
about 40 mils, and more desirable ranges from about 5 mils to about
30 mils. As illustrated in another embodiment in FIG. 2a, the
flanges 16 may be coined to form channels 19 so that the material
thickness t at the perforation lines 18 is less than or equal to
that of the remaining portion of the flanges.
[0018] The method of making the multiple portion packaging tray 10
is illustrated in FIG. 3. The multiple portion packaging tray 10
can be made using any suitable polymer sheet or film forming
process, but is desirably made using a thermoforming process 24.
Suitable thermoforming methods include solid phase pressure
forming, melt phase forming, plug assist, vacuum forming, and drape
forming. The thermoforming process 24 occurs in a former 28
comprising a form station 30 and a separate trim station 32. A
pliable polymer sheet 26 is indexed through the form station 30 to
create the formed multiple portion packaging tray 10 using
thermoforming methods known to those skilled in the art. Desirably,
the mold temperature of the former 28 is controlled using cold
water flow through internal channels in the mold to quench the
formed multiple portion packaging tray 10 so that there is
crystallization of the polymer. The cooling process is well known
to those of skill in the art.
[0019] The trim station 32, illustrated in an exploded schematic in
FIG. 4, comprises steel rule knives 40 to cut the perimeter of the
formed multiple portion packaging tray 10. The trim station 32
further comprises notched steel rule knives 42a and 42b, best shown
in FIGS. 5a and 5b to create a series of alternating openings 20
and land areas 22 in the longitudinal direction of the respective
tear lines 18. As illustrated in FIG. 5, the notched knives 42a and
42b comprise standard straight blade steel rule knife material with
notches 44a and 44b sized to create land areas of a predetermined
size so that the individual containers 12 are easily separated by
tearing apart the flanges 16 at the perforation lines 18 without
propagating cracks across the flanges 16. The perimeter knives 40
can also have small notches to create tabs attaching the multiple
portion packaging tray 10 to the polymer sheet 26. The steel knives
40 and 42a and 42b touch a striker plate 46 to trim the perimeter
of the multiple portion packaging tray 10 and to create the
openings 20 and land areas 22 of the perforation lines 18. In
another embodiment, the trim station 32 further comprises a punch
and die system, well known to those of skill in the art, at the
points where the individual containers 12 meet on the multiple
portion packaging trays 10. The cutting by the steel knives 40 and
42a and 42b and punch and die system may be done simultaneously or
in separate steps.
[0020] The multiple portion packaging trays 10 may be indexed to a
stacking station 36 where the perimeter tabs are broken by pushing
the array of containers 10 through the sheet 26 to a stacking
chamber where they are counted and pushed to a packaging station
38.
[0021] The present invention is further illustrated by the
following example, which is not to be construed in any way as
imposing limitations upon the scope thereof. On the contrary, it is
to be clearly understood that resort may be had to various other
embodiments, modifications, and equivalents thereof which, after
reading the description therein, may suggestion themselves to those
skilled in the art without departing from the spirit of the present
invention and/or the scope of the appended claims.
EXAMPLE
[0022] A 30 mil 100% polypropylene sheet is used to make a multiple
portion packaging tray. The polypropylene sheet is heated to
160.degree. C. as it indexes through an oven into the form station
at 4 second cycles. In the form station, the hot sheet may be
formed using a variety of methods. The formed multiple portion
packaging tray leaves the forming station, still attached to the
sheet. The formed multiple portion packaging tray enters the trim
station approximately 8 seconds after leaving the forming station.
At the trim station, a lower platen moves up to the sheet level to
capture the individual containers in a die plate. An upper platen
containing steel rule knives, notched steel rule knives, and
punches moves downward until it just touches the die plate and
trims the perimeter of the multiple portion packaging tray as well
as forms the tear lines in the flanges with alternating opening and
land areas. The notches of the notched steel rule knives are
desirably 20 mils in length. The upper and lower platens return to
their initial positions and the multiple portion packaging tray
proceeds to the stacking station. In the stacking station, a ram
below sheet level pushes the multiple portion packaging tray up
through the sheet, separating the multiple portion packaging tray
from the sheet, and feeds the multiple portion packaging tray into
a stacking chamber. The multiple portion packaging trays are
collected in the stacking chamber and pushed onto a conveyor for
packing.
[0023] It should be understood that the foregoing relates to
particular embodiments of the present invention, and that numerous
changes may be made therein without departing from the scope of the
invention as defined from the following claims.
* * * * *