U.S. patent application number 10/393087 was filed with the patent office on 2004-08-19 for retortable light excluding container and methods of using same.
Invention is credited to Barca, John G., Gamel, Melissa J., Harp, Douglas A., Macauley, R. Peter, Stokesbury, Elwood L., Yuan, Jay Z..
Application Number | 20040161558 10/393087 |
Document ID | / |
Family ID | 33096744 |
Filed Date | 2004-08-19 |
United States Patent
Application |
20040161558 |
Kind Code |
A1 |
Gamel, Melissa J. ; et
al. |
August 19, 2004 |
Retortable light excluding container and methods of using same
Abstract
A container includes a gripping groove and a panel structure
that allows it to withstand retort or heat sterilization of a low
acid liquid nutritional product contained therein. The container
can be formed of a multilayer material that has titanium dioxide
and iron oxide in an intermediate regrind layer and in at least one
of its inner and outer layers. The titanium dioxide and iron oxide
are provided together in the same meltable pellets, which are used
for forming the container.
Inventors: |
Gamel, Melissa J.;
(Delaware, OH) ; Macauley, R. Peter; (Westerville,
OH) ; Stokesbury, Elwood L.; (Westerville, OH)
; Harp, Douglas A.; (Westerville, OH) ; Barca,
John G.; (Dublin, OH) ; Yuan, Jay Z.; (Mason,
OH) |
Correspondence
Address: |
STEVEN F. WEINSTOCK
ABBOTT LABORATORIES
100 ABBOTT PARK ROAD
DEPT. 377/AP6A
ABBOTT PARK
IL
60064-6008
US
|
Family ID: |
33096744 |
Appl. No.: |
10/393087 |
Filed: |
March 20, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10393087 |
Mar 20, 2003 |
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29175332 |
Feb 3, 2003 |
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29175332 |
Feb 3, 2003 |
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29175310 |
Feb 3, 2003 |
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Current U.S.
Class: |
428/35.7 ;
428/500 |
Current CPC
Class: |
B65D 1/0215 20130101;
B32B 2439/60 20130101; B32B 27/20 20130101; B32B 2272/00 20130101;
B32B 2307/306 20130101; B32B 2264/102 20130101; B32B 27/32
20130101; B65D 23/102 20130101; Y10T 428/31855 20150401; Y10T
428/1352 20150115 |
Class at
Publication: |
428/035.7 ;
428/500 |
International
Class: |
B65D 001/00 |
Claims
What is claimed is:
1. A multilayer material comprising: an inner layer; an outer
layer; a regrind layer disposed between the inner layer and the
outer layer; wherein the regrind layer and at least one of the
outer layer and the inner layer contain titanium dioxide and iron
oxide.
2. A multilayer material according to claim 1, wherein the outer
layer contains titanium dioxide and iron oxide.
3. A multilayer material in accordance with claim 1, wherein the
inner layer and the outer layer contain titanium dioxide and iron
oxide.
4. A multilayer material in accordance with claim 1, wherein the
inner layer comprises an ethylene-polypropylene copolymer.
5. A multilayer material in accordance with claim 1, wherein the
outer layer comprises an ethylene-polypropylene copolymer.
6. A multilayer material in accordance with claim 1, wherein the
inner layer and the outer layer include an identical
ethylene-polypropylene copolymer.
7. A multilayer material in accordance with claim 1, further
comprising an oxygen barrier layer, a first adhesive layer, and a
second adhesive layer, the first adhesive layer constructed to bond
the oxygen barrier layer to an outer surface of the regrind layer
and the second adhesive layer constructed to bond the oxygen
barrier layer to an inner surface of the outer layer.
8. A multilayer material in accordance with claim 7, wherein the
oxygen barrier layer is constructed from a material comprising
ethylene vinyl alcohol.
9. A container for a light-sensitive product, said container
comprising: an inner layer; an outer layer having an inner surface;
a regrind layer disposed between said inner layer and said outer
layer, said regrind layer having an outer surface; a first adhesive
layer disposed adjacent said outer surface of said regrind layer; a
second adhesive layer disposed adjacent said inner surface of said
outer layer; an oxygen barrier layer disposed between said first
adhesive layer and said second adhesive layer, said first and
second adhesive layers constructed to bond said oxygen barrier
layer to said regrind layer and to said outer layer, respectively;
said outer layer containing titanium dioxide and iron oxide; and
said regrind layer containing titanium dioxide and iron oxide.
10. A container according to claim 9, wherein the inner layer
contains titanium dioxide and iron oxide.
11. A container in accordance with claim 9, wherein the titanium
dioxide and iron oxide are provided together in common meltable
resin pellets and extrusion blow molded to form the retortable
container
12. A multilayer material in accordance with claim 9, wherein the
inner layer and the outer layer include an identical
ethylene-polypropylene copolymer.
13. A retortable plastic bottle comprising: a multilayer material
that defines a side wall, a bottom wall, and an open top; the
multilayer material comprising an inner layer, an outer layer, and
a regrind layer disposed between the inner layer and the outer
layer, wherein the regrind layer and at least one of the outer
layer and the inner layer contain titanium dioxide and iron oxide;
the side wall including an upper portion having a convex dome shape
and terminating at an upper end in a finish adapted to be
hermetically sealed by a cap, a lower portion joined to the bottom
wall, and an intermediate portion disposed between the upper
portion and the lower portion; the intermediate portion of the side
wall defining an arcuate annular gripping groove; and the lower
portion being substantially cylindrical at upper and lower ends
thereof and including between the substantially cylindrical upper
and lower ends a panel structure comprising a plurality of
vertically elongated rectangular indentations separated by a
corresponding plurality of longitudinal beams members each having
an arcuate lateral cross section.
14. A container in accordance with claim 13, wherein each of the
rectangular indentations includes a centrally located raised island
that has a vertically elongated generally rectangular base,
opposing inwardly sloped side walls, and opposing inwardly sloped
end walls.
15. A container in accordance with claim 13, wherein the gripping
groove has a radius of approximately 0.3 inches-0.5 inches (7.62
mm-12.70 mm).
16. A container in accordance with claim 15, wherein the gripping
groove has a radius of approximately 0.328 inches (8.33 mm).
17. A method of packaging a low acid liquid nutritional product
comprising the steps of: forming a container of comprising: a side
wall, a bottom wall, and an open top; the side wall including an
upper portion having a convex dome shape and terminating at an
upper end in a finish adapted to be hermetically sealed by a cap, a
lower portion joined to the bottom wall, and an intermediate
portion disposed between the upper portion and the lower portion;
the intermediate portion of the side wall defining an arcuate
annular gripping groove; and the lower portion of the side wall
being substantially cylindrical at upper and lower ends thereof and
including between the substantially cylindrical upper and lower
ends a panel structure comprising a plurality of vertically
elongated rectangular indentations separated by a corresponding
plurality of longitudinal beams members; providing a cap adapted to
sealingly mate with the finish of the container; sterilizing the
container and the cap; filling the container with a low acid liquid
nutritional product; hermetically sealing the open top of the
filled container with the cap; and heat sterilizing the sealed
container in a retort process.
18. A method of packaging a low acid liquid nutritional product in
accordance with claim 17, wherein the step of forming the container
of comprises co-extrusion blow molding a multilayer material that
defines the side wall, the bottom wall, and the open top; the
multilayer material comprising an inner layer, an outer layer, and
a regrind layer disposed between the inner layer and the outer
layer, wherein the regrind layer and at least one of the outer
layer and the inner layer contain titanium dioxide and iron
oxide.
19. A method of packaging a low acid nutritional product in
accordance with claim 17, wherein the retort process is carried out
at temperature of at least 120.degree. C.
20. A method of packaging a low acid liquid nutritional product in
accordance with claim 18, wherein the retort process is carried out
at temperature of approximately 126.1 to 127.2.degree. C.
21. A method of protecting a light sensitive liquid nutritional
product comprising the steps of: mixing a plurality of meltable
color pellets with a base material, each of the color pellets
containing both titanium dioxide and iron oxide; heating the color
pellets and the base material; and molding the heated and mixed
color pellets and base material to form a layer of a container
adapted to hold a light sensitive liquid nutritional product.
22. A method of protecting a light sensitive liquid nutritional
product according to claim 21, wherein the molding step is
accomplished by extrusion blow molding and the layer formed is an
outer layer of the container.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 29/175,332 entitled Container and Cap, filed
Feb. 3, 2003, which is a continuation-in-part of U.S. patent
application Ser. No. 29/175,310 entitled Container, filed on filed
Feb. 3, 2003.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to the field of
containers, and more particularly to a retortable light excluding
plastic container for use with light sensitive low acid liquid
nutritional products.
[0003] Low acid liquid food products generally contain nutrients
that are light and temperature sensitive. Examples of such liquid
foods are nutritional products for infants and nutritious products
for persons having specific medical conditions or dietary needs. As
used herein and in the claims a "low acid liquid nutritional
product" is a liquid nutritional product, other than alcoholic
beverages, with a finished equilibrium pH of greater than 4.6.
While high acid nutritional products, such as fruit juices and the
like, can be cooked and then "hot-filled" into sterile containers
in an aseptic filling enclosure; low acid liquid nutritional
products must be placed in a sterile container, sealed and then
made commercially sterile using a conventional heat and pressure
retort process. This post-filling pressurized heat sterilization is
often carried out in a batch mode with temperatures in the range of
approximately 120-130 degrees Celsius or Centigrade (.degree. C.),
which is approximately 248-266 degrees Fahrenheit (.degree. F.).
However, prolonged exposure to high temperatures during retort or
prolonged exposure to light can result in damage to the biological
activity of the nutrients in the product.
[0004] For example, low acid liquid nutritional products typically
contain nutrients, including but not limited to vitamins such as
vitamin B2 (riboflavin) and vitamin A, that are sensitive to light.
Exposure of such food products to light can result not only in
damage to the biological activity of these nutrients, but also to
the taste or other characteristics of the products. This presents a
particular challenge in the packaging of food products, including
medical and pediatric nutritional products, because such products
are subject to labeling requirements that require that the
nutritional contents, e.g., vitamin contents, of the food product
be specifically identified. In those cases in which the listed
nutritional contents are sensitive to light, there may be a
reduction in the amount or activity of one or more of the
nutritional contents of the product over time due to light
exposure, thereby causing the food product to be out of compliance
with its labeling. In such a situation, it may be necessary to
reduce the shelf life of the food product, and thus increase the
cost of the food product. Alternatively, it may be necessary to
increase volume of the nutritional contents of the product, for
example, by way of vitamin fortification, which also increases the
cost of the food product. It is preferable that a light-protective
package be provided so that the nutritional contents of the product
remain within the ranges specified in the labeling, thereby
providing a longer shelf life for the product.
[0005] Metal cans have conventionally been the preferred means for
containing low acid liquid nutritional products in order to provide
the needed opaqueness, vitamin protection and hermeticity. However,
metal cans are typically not resealable and their weight adds to
shipping costs. Metal cans are not resiliently deformable and
customers may perceive a dented metal can to indicate a "defective
product" that should be returned to the manufacturer, even when the
contents are actually unharmed. Some manufacturers have tried
relative simple cylindrical-shaped plastic cans, but such cans
often distort as a result of the retort process. In addition to the
customer perception problem discussed above, permanent plastic
container distortion and the resulting shape variances lead to
handling problems for the manufacturer during later packaging
operations, which are often highly automated.
[0006] U.S. Pat. No. 5,750,226 to Macauley, et al. discloses a
bottle designed to provide protection for light-sensitive products
contained therein. U.S. Pat. No. 5,750,226 is incorporated herein
by reference, in its entirety. Macauley, et al. disclose a bottle
having a multi-layered wall structure. The wall includes inner and
outer layers of food grade polypropylene, a regrind layer
positioned between the inner and outer layers of food grade
polypropylene, and a pair of high temperature adhesive layers. The
wall further includes oxygen barrier layer. The adhesive layers
serve to bond the other layers to the barrier layer. Titanium
dioxide (TiO.sub.2) is incorporated into the food grade
polypropylene layers and into the regrind layer in order to reduce
light transmission through the wall. The titanium dioxide imparts a
white color to each layer in which it is present.
[0007] Titanium dioxide is an inert material that can be used in
both retort and aseptic packaging techniques. Titanium dioxide is a
reflective material, i.e., it works by reflecting light away from
the contents of the product. Although titanium dioxide effectively
reflects light having a wavelength above approximately 500
nanometers, it has been found that some light having a wavelength
below 500 nanometers is reflected when a bottle wall contains
relatively high amounts of titanium dioxide. However, as discussed
in U.S. Pat. No. 5,750,226, high concentrations of titanium dioxide
can create significant problems in the manufacturing of plastic
containers. In addition, it can be difficult to achieve high
titanium dioxide concentrations in relatively thin container
walls.
[0008] Thus, there is a need for an improved plastic container and
method for packaging a low acid liquid nutritional product. A
primary objective of this invention is to meet that need.
[0009] Another objective of this invention is the provision of a
container capable of withstanding heat sterilization in a retort
process at temperatures of approximately 120-130.degree. C.
(248-266.degree. F.) without significant permanent deformation.
[0010] Another objective of this invention is the provision of a
material for enhancing the light excluding properties of a
container for low acid liquid nutritional products.
[0011] Another objective of this invention is to reduce the
percentage by weight of titanium dioxide required in a container so
as to reduce cost, process variability, and wear on tooling, yet
maintain or enhance the light excluding characteristics of the
container.
[0012] Another objective of this invention is to provide a
container that is aesthetically pleasing, as well as easy for
automated packaging equipment and consumers to handle.
[0013] These and other objectives will be apparent to one skilled
in the art upon studying the drawings, description and claims that
follow.
SUMMARY OF THE INVENTION
[0014] The present invention relates to the field of retortable
containers in general, and more particularly to a plastic container
for use in packaging light sensitive low acid liquid nutritional
products.
[0015] A first aspect of the present invention is that the
container can be constructed of a light excluding multilayer
material that includes an inner layer, an outer layer, and a
regrind layer disposed therebetween. The regrind layer and at least
one of the inner and outer layers contain titanium dioxide and iron
oxide. Optionally, oxygen barrier and adhesive layers can be
included if desired.
[0016] A second aspect of the present invention is that container
is formed with a side wall and bottom wall configuration that
allows it to withstand the retort process. The side wall includes
upper, intermediate and lower portions. The upper portion has a
convex dome shape, the intermediate portion includes a gripping
groove that makes it easier to grasp the container, and the lower
portion includes a panel structure defined by a plurality of
vertically elongated substantially rectangular indentations
separated by a corresponding plurality of longitudinal beams.
Optionally, the indentations can include centrally located raised
islands therein. The bottom wall can include centrally located
primary and secondary recesses that further contribute to the
container's capability to withstand the retort process.
[0017] A third aspect of the present invention is the provision of
a new method of packaging a low acid liquid nutritional product.
The method includes the steps of forming the container as described
herein, providing a cap to sealingly mate with the finish of the
container, sterilizing the container and cap, filling the container
with the low acid liquid nutritional product, hermetically sealing
the filled container with the cap, and then heat sterilizing the
sealed container in a retort process.
[0018] A fourth aspect of the present invention is the provision of
a new method of protecting a light sensitive nutritional product.
The method includes the steps of mixing a plurality of meltable
color pellets, each containing both titanium dioxide and iron
oxide, with a base material, heating the color pellets and the base
material, and molding the heated and mixed color pellets and base
material to form a layer of a container adapted to hold a light
sensitive liquid nutritional product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a front elevational view of a bottle or container
constructed in accordance with the present invention.
[0020] FIG. 2 is a right side elevational view of the container of
FIG. 1.
[0021] FIG. 3 is a rear elevational view of the container of FIG.
1.
[0022] FIG. 4 is a top plan view of the container of FIG. 1.
[0023] FIG. 5 is a bottom plan view of the container of FIG. 1.
[0024] FIG. 6 is an enlarged fragmentary cross-sectional view taken
along line 6-6 in FIG. 2 and shows a container wall material
constructed in accordance with one embodiment of the present
invention.
[0025] FIG. 6A is an enlarged fragmentary cross-sectional view
similar to FIG. 6 and shows another embodiment of the present
invention.
DETAILED DESCRIPTION
[0026] The container or bottle of the present invention is
generally designated in the figures by the reference numeral 10.
The container 10 is particularly suitable for use in packaging and
refrigerated or non-refrigerated storage of medical and pediatric
nutritional products such as the products manufactured and sold by
Abbott Laboratories through its Ross Products Division. The light
barrier characteristics of container 10, as described in detail
herein, provided enhanced protection for the nutritional contents,
e.g., vitamin contents, of such products. However, it is to be
understood that container 10 of the present invention can be used
in the packaging (by retort or otherwise) and storage of other
light sensitive products without departing from the scope of the
present invention.
[0027] The semi-rigid container 10, which is illustrated in FIGS.
1-5, has a hollow body constructed from a multi-layered wall
material 12. As best seen in FIG. 6, the wall material has an outer
layer 14, an inner layer 16, and a regrind layer 18 disposed
between the outer layer 14 and the inner layer 16. In an embodiment
of the present invention in which container 10 is constructed to
contain a food product, one of ordinary skill in the art will
appreciate that outer layer 14 and inner layer 16 can be
constructed of plastic, preferably a heat set food grade plastic.
More preferably, the layers 14, 16 are preferably constructed of
random copolymers containing polypropylene.
[0028] It is preferred, but not required, to construct outer layer
14 and inner layer 16 of the same identical material. Although many
food grade plastic materials will suffice, the base or virgin
material for the inner and outer layers is most preferably an
ethylene-polypropylene random copolymer available from ExxonMobil
Chemical Company of Houston, Tex., U.S.A. under the trade
designation PP-9122. The ExxonMobil PP-9122 material (hereinafter
PP) comes in the form of a plurality of meltable resin pellets,
preferably of substantially uniform chemical composition.
[0029] A plurality of meltable resin colorant pellets of
substantially uniform chemical composition are mixed, melted, and
molded with the virgin PP material to form the outer and/or inner
layers 14, 16. The colorant pellets are manufactured by the Ferro
Corporation of Independence, Ohio, U.S.A. under the trade
designation FERRO CH 010742FLB. The colorant pellets include both
titanium dioxide (TiO.sub.2) and iron oxide (FeO.sub.2) in a common
pellet, i.e., the same pellet. The titanium dioxide lends a white
hue to the colorant pellet and the iron oxide adds a slight amount
of black hue, such that overall the colorant pellet has a
substantially white or very light grayish hue.
[0030] Thus, outer layer 14 and/or inner layer 16 in the exemplary
embodiment of the present invention may contain light barrier
additives such as titanium dioxide and iron oxide. The presence of
titanium dioxide and iron oxide in outer layer 14 imparts a
substantially white color to outer layer 14 that is aesthetically
pleasing, thereby making multi-layered material 12 useful in the
manufacture of containers for consumer products. Similarly, the
presence of titanium dioxide and iron oxide in inner layer 16
imparts a substantially white or grayish color to inner layer 16.
When multi-layered material 12 is used in the packaging of food
products, it may be desirable to provide a substantially
white-colored inner wall in order to provide an aesthetically
pleasing appearance to the interior of the package. Thus, when a
customer looks into the interior of the package, he/she will see a
light grayish inner wall surrounding the product contained in the
package. The multilayer material is free of an interlayer of black
pigment compound resin disposed between the regrind layer 18 and
one of the inner layer 16 and the outer layer 14. This reduces the
complexity and cost of the material.
[0031] Of course, the thickness of outer layer 14 and inner layer
16 respectively can vary depending on the packaging needs
encountered. However, the U.S. Code of Federal Regulations calls
for inner layer 16 to have a minimum thickness of approximately
0.002 inches (0.0508 mm) when container 10 is used to contain a
food product. In an exemplary embodiment of the present invention,
inner layer 16 has a minimum thickness of approximately 0.002
inches (0.0508 mm), while outer layer 14 has a minimum thickness of
approximately 0.002 inches (0.0508 mm).
[0032] Regrind layer 18 can be constructed from a variety of
materials. For example, up to approximately sixty percent (60%) by
weight of the regrind layer 18 can be constructed from material
re-ground from the trim waste of the bottle blow operation used to
form the container 10 of this example. The balance of the regrind
layer can include virgin PP materials and optionally up to
approximately three percent (3%) by weight of EVALCA GF-20, which
is used a scrubber, filtering or purifying agent.
[0033] Of course, the regrind layer 18 includes the titanium
dioxide and iron oxide colorants contributed by the re-ground
material. The colorant pellets described above can also be added to
the virgin PP materials added to the regrind, as necessary to
maintain the desired equilibrium colorant level in the regrind
layer 18. Because the colorant pellet includes both the titanium
dioxide and iron oxide colorants in a relatively fixed amount or
ratio and only one colorant pellet is used, rather than separate
pellets for TiO.sub.2 and FeO.sub.2 respectively, the amount of
colorant to add to the regrind layer 18 to achieve the desired
steady state equilibrium level is easier to calculate. The mixing
process and the resulting color of the inner and outer layers are
easier to control because one less factor is variable. One
unexpected result is that the total amount of abrasive titanium
dioxide used in the container 10 can actually be reduced to less
than five percent (5%) by weight, and more preferably to
approximately 3.5%.
[0034] Also in this exemplary embodiment, regrind layer 18 has a
minimum thickness of approximately 0.007 inches (0.1778 mm). The
overall minimum thickness of the container 10 is approximately
0.015 inches (0.381 mm). One of ordinary skill in the art will
appreciate that other wall thicknesses are possible without
departing from the scope of the present invention.
[0035] Multi-layered wall material 12 may optionally include an
oxygen barrier layer 24, as depicted in FIG. 6A. Oxygen barrier
layer 24 can be constructed of a variety of materials that are
known to provide oxygen barrier characteristics, e.g., ethylene
vinyl alcohol (EVOH) and nylons. In one embodiment of the present
invention, oxygen barrier layer 24 is constructed of an ethylene
vinyl alcohol EVOH copolymer resin. The EVOH resin is preferably
EVALCA EVAL LC F101-AZ, available from EVAL Company of America
(EVALCA), a subsidiary of Kuraray Co. Ltd. of Japan. The barrier
layer preferably has a minimum continuous thickness of
approximately 0.0005 inches (0.0127 mm). However, it can be
appreciated that the thickness of the oxygen barrier layer 24 may
vary without departing from the scope of the present invention. For
example, oxygen barrier layer 24 can have a thickness of
approximately 0.0002 inches-0.002 inches (0.00508 mm-0.0508
mm).
[0036] In the embodiment shown in FIG. 6A, an inner surface of
outer layer 14 is bonded to oxygen barrier layer 24 by way of first
adhesive layer 20. An outer surface of regrind layer 18 is bonded
to the opposite side of oxygen barrier layer 24 by way of second
adhesive layer 22. Thus, oxygen barrier layer 24 is disposed
between the outer layer 14 and the regrind layer 18. Placement of
the oxygen barrier layer 24 in this position protects layer 24 from
moisture that may render it ineffective. In addition, placement of
the oxygen barrier layer 24 in this position moves the adhesive
layers 20, 22 farther away from the contents of container 10. It
will be appreciated that placing the adhesive layers 20, 22 farther
away from the contents of container 10 is desirable in those cases
in which interaction between the adhesive and the contents may be
detrimental to the contents of container 10. One of ordinary skill
in the art will recognize that oxygen barrier layer 24 can have
other positions relative to inner layer 16, regrind layer 18, and
outer layer 14.
[0037] First and second adhesive layers 20, 22 can be constructed
of a variety of known adhesive materials known to be useful in
bonding materials of the type included in multi-layered wall
material 12. For example, first and second adhesive layers 20, 22
can be constructed from polyolefin, e.g., a polyolefin layer having
a minimum thickness of approximately 0.0001 inches (0.00254 mm). In
the preferred embodiment, the first and second adhesive layers are
constructed of MITSUI ADMER QB-520A, available in meltable pellet
form from Mitsui Chemicals America, Inc. of Purchase, New York,
U.S.A. The minimum values for thickness of the outer, inner, and
regrind layers are as stated above and a minimum overall wall
thickness for the container 10 of approximately 0.015 inches (0.381
mm) is still preferred in the embodiment illustrated in FIG. 6A.
The container 10 of this embodiment has been found to be suitable
for containing approximately eight ounces of low acid nutritional
product and withstands heat sterilization, up to 130.degree. C.
(266.degree. F.), in a conventional retort process without
substantial permanent deformation.
[0038] The container 10 of this invention is co-extrusion blow
molded in a conventional manner, with the materials for the layers
being provided in re-ground or pellet form as described above,
mixed, heated and delivered to the appropriate extrusion passages
of a multi-station blow wheel molding machine. After molding, the
containers are trimmed of excess material or flash and faced to
provide the required finish 26 for a hermetic seal by a mating
threaded cap or closure. The cap is not shown here but is disclosed
in German et al. U.S. Pat. No. 6,276,543, which is incorporated by
reference herein.
[0039] The present invention provides a method of packaging a low
acid liquid nutritional product that is unique and advantageous
over prior methods. The method includes the steps of forming the
container 10 with the structural features described below,
providing a cap adapted to sealingly mate with the finish of the
container, sterilizing the container and the cap, filling the
container with a low acid liquid nutritional product, hermetically
sealing the open top of the filled container with the cap, and heat
sterilizing the sealed container in a retort process. For example,
in the case of a container 10 filled with 8 fluid ounces (237 mL)
of ENSURE.RTM. liquid nutritional product made by the Ross Products
Division of Abbott Laboratories, the retort process is carried out
as follows. The filled and sealed containers are heated for
approximately 13 minutes from ambient room temperature to
sterilizing temperature of approximately 126.degree. C.
(260.degree. F.). The sterilizing temperature is held for
approximately 6 minutes. The peak pressure at the end of the dwell
period is approximately 2.48 bar (36 psig). After the dwell, there
is a cooling period of approximately 20 minutes. Advantageously the
retort process can be carried out at temperature of at least
120.degree. C. (248.degree. F.), more advantageously up to
approximately 130.degree. C. (266.degree. F.), and most preferably
approximately 126.1 to 127.2.degree. C. (259-262.degree. F.). The
method can utilize a single layer material or the multilayer
material and the co-extrusion blow molding process described
above.
[0040] Referring to FIGS. 1-5, the container 10 of this invention
has a bottom wall 28 and a side wall 30, preferably of
substantially uniform thickness, joined to the bottom wall 28 to
define an open top 32. The side wall 30 has an upper portion 34, an
intermediate portion 36, and a lower portion 38. The upper portion
34 has a convex dome shape and terminates at its upper end in a
neck and the bottle finish 26. The intermediate portion 36 defines
an arcuate annular gripping groove 40 that allows the user to
easily grasp the container 10 with the thumb and index or
forefinger of one hand. A full radius of approximately 0.3 to 0.5
inches (7.62 mm-12.7 mm), and more preferably approximately 0.328
inches (8.33 mm), defines the gripping groove 40. Most users can
comfortably grasp the container 10 by engaging the groove 40 with
any one of their other fingers, too. The groove 40 also provides a
strong structural hoop for evenly transferring and/or resisting the
stresses encountered during the retort process.
[0041] The lower portion 38 has upper and lower ends or end
portions 42, 44 respectively that are substantially cylindrical and
a panel structure 46 therebetween. The panel structure 46 includes
a plurality of vertically elongated, more preferably rectangular,
indentations 48 separated by a corresponding plurality of
longitudinal beam members 50. Each of the beam members 50 has an
arcuate, more preferably circular, lateral cross section that
blends smoothly with the substantially cylindrical upper and lower
end portions 42, 44. In the preferred embodiment shown, there are
six identical opposing indentations 48 separated by six identical
opposing beam members 50.
[0042] Each of the indentations 48 has a raised island therein.
Preferably the island is centrally located within the perimeter of
the indentation 48 and has a substantially rectangular base. The
islands 52A, 52B, and 52C have different shapes depending on their
location. One pair of opposing islands 52A has identical opposing
sides 54A and identical ends 56A that slope inwardly in a
four-sided pyramidal manner toward a substantially rectangular flat
plateau 58A at the top of the island 52A. One of the opposing
islands 52A has a substantially flat recessed area 59, which allows
excess flash material left from the ejector pin in the mold to be
ground off without adversely impacting the strength or outermost
profile of the container 10. Another pair of opposing islands 52B
has opposing sides 54B, 54B' and mirror image ends 56B, 56B' that
slope inwardly toward a substantially rectangular flat plateau 58B.
However, side 54B slopes inwardly at a steeper angle than side
54B'. Thus, side 54B' has a greater surface area than side 54B.
Another pair of opposing islands 52C is constructed such that each
island 52C is a mirror image of the adjacent island 52B. Thus, the
resulting pyramidal structures 52C are skewed in the opposite
direction of the islands 52B and have sides 54C, 54C', ends 56C,
56C' and a plateau 58C. Each of the indentations 48 includes a
sloped planar surface 60 that extends outwardly and downwardly at
an acute angle from the bottom of the indentation to join the lower
end portion 44.
[0043] As best seen in FIG. 5, the bottom wall 28 of the container
10 also has a configuration that contributes resistance to
permanent deformation. The bottom wall configuration is disclosed
in U.S. Pat. No. 5,269,437, which is assigned to Abbott
Laboratories and incorporated in its entirety by reference herein.
In the preferred embodiment, the bottom wall 28 includes a circular
or conical primary recess 61 and a substantially flat elliptical
secondary recess 62, which are both centrally disposed. The
secondary recess 62 has a major axis and a minor axis. The distance
across the secondary recess 62 along the major axis divided by the
distance across the secondary recess 62 along the minor axis is
greater than one but not greater than three. A substantially flat
circular annular ring 64 or resting surface surrounds the recesses
61, 62. The bottom wall 28 slopes upwardly and inwardly along the
primary recess 61 to join the secondary recess 62 and the ring
64.
[0044] Although the present invention has been described herein
with respect to certain exemplary and preferred embodiments, one of
ordinary skill in the art will appreciate that various
modifications can be made to the multilayer material, the container
formed therefrom, and the packaging process without departing from
the scope of the invention, which is defined in the appended
claims.
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